Dissertations / Theses: 'Physico-chemical analyzes'

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Powell, Francis E. "Physico-chemical studies in flow analysis." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/25925.

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The first part of this study was the characterisation of an impinging jet electrode in an amperometric detector; the device having found extensive application in flow injection analysis. A voltammetric study of the detector in the stopped flow mode was carried out and evidence is presented of restricted diffusion imposed by the shallow depth of the cell. In hydrodynamic voltammetry, the detector exhibited a gradual progression from thin-layer to wall jet behaviour as the flow rate increased. This gradation is discussed in terms of a model in which flow in the electrode chamber forms concentric rings, the streamlines being successively perpendicular, oblique and parallel to the electrode. The response of the detector and its associated equipment was studied by two experiments. Firstly, the fidelity of the electrochemical instrumentation and recording system was ascertained from its electronic response to a RC (resistance-capacitance) circuit functioning as a flow injection transport analogue. Secondly, the dynamic response of the electrochemical cell was established from an experiment using a concentration step input delivered through a short, straight manifold. The results indicated that laminar flow in the delivery tube was modified by mixing stages in the cell channel and its connections to produce a final dispersion which defines an effective detection volume of only 7μL. The electronic and cell responses indicate that the total detection system would impose little extra dispersion in a practical flow injection line. In the second part of this study, photometric titrations were carried out in a stirred tank reactor in which the volume changed linearly with time. The general relation for the concentration gradient when the tank is used as a mixing device was examined experimentally under various flow conditions. In particular, the precision of linear concentration gradients was ascertained when peristaltic pumping was employed. These gradients were utilised to titrate analyte within the tank by means of titrant delivered by pump flow with photometric detection in an exit stream. Self-indicating titrations, following changes in the absorbance of analyte, titrant or reaction product, were performed each conforming to theoretical prediction. Due to the external detection system employed, dispersion and transportation lag effects were observed and accounted for.

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Ševčík, Marek. "Vývoj kompozitů na bázi alkalicky aktivovaných matric odolných vůči působení extrémních teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-444262.

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The diploma thesis is focused on the development of composites from alkali activated materials (AAM) and their resistance to extreme temperatures. The theoretical part describes alkaline activation and precursors for the production of AAM. Furthermore, the problem of the effect of extreme temperatures on these materials is described. In the experimental part, the optimal silicate modulus with respect to the properties of AAM was gradually determined, and the effect of extreme temperatures on the AAM matrix was verified. In the next stage, the effect of the filler with respect to the behavior at extreme temperatures was tested and then the final formulation was optimized.

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Díez, Orrite Silvia. "Physico-chemical properties of polymers at interfaces." Doctoral thesis, Universitat Rovira i Virgili, 2002. http://hdl.handle.net/10803/8511.

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A polymer is a large molecule constructed from many smaller structural units called
monomers joined together by covalent bonds. Polymers have existed in natural form
since life began and those such as DNA, RNA, proteins and polysaccharides are some
of the most important macromolecules found in plant and animal life. From the earliest
times, the man has used many of these polymers as materials for providing clothing,
decoration, tools, weapons and other requirements. However, the origins of today's
polymer industry commonly are accepted as being in the nineteenth century when
important discoveries were made concerning to the modification of certain natural
polymers, as cellulose. The use of synthetic and natural polymers as stabilisers for
colloid systems (sols, dispersions, microemulsions, etc.) is becoming more important
everyday in contemporary life. Polymer additives can be applied in preconcentrations
and dehydration of suspensions in mineral processing, purification of wastewater and
even in nutritional and pharmaceutical emulsions being their importance related to the
characteristics of the process and the properties that they show. The present work aims
to develop appropriate numerical and analytical modelling techniques, which can
describe (considering the formation of loops and tails) the structure of a polymeric layer
adsorbed on heterogeneous surfaces; this adsorbed layer is an relevant factor in the
properties showed by this kind of materials. Taking into account this, the methodology
known as Single Chain Mean Field (SCMF) (originally used to study micellar
aggregates and grafted polymers) was modified to apply on polymer adsorption
problems. In this way, it was possible to calculate numerically properties that can be
experimentally measured, such as total monomer volume fraction profiles, loop and tail
volume fraction profiles, adsorbance or the thickness of the adsorbed layer. The
structure of the polymeric layer was examined both for flat and spherical (colloidal
particles) surface geometries. When compared with other well established
methodologies for the numerical simulation of polymeric systems, this new version of
SCMF was found to be more efficient due to the improved sampling of the polymer
chain configuration space.
Thus, SCMF method results, in the case of the adsorption on flat surfaces, compare well
with those obtained either with Monte Carlo simulations or with the method developed
in the 80s by Scheutjens and Fleer (SCF). Due to the lack of studies focusing to polymer
adsorption on colloidal particles, our results have been the first to present quantitative
predictions of the structure of the polymeric layer adsorbed on a spherical surface. Thus,
we have demonstrated the dependence of the adsorbed polymer layer with the size of
the colloidal particle as well as the characteristic lengths that influence on it. Finally, in
this work an analytical approach for the description of polymer-colloidal mixtures has
been developed which compares well with the numerical results obtained from the
SCMF methodology. Furthermore, the analytical approach is able to predict system
behaviours, as for example the formation of gels.
Un polímero es una molécula de grandes dimensiones formada de pequeñas unidades
llamadas monómeros, los cuales se encuentran unidos por medio de enlaces covalentes.
Los polímeros han existido de forma natural desde el comienzo de la vida, y aquellos
como el DNA, RNA o las proteínas son algunos de los polímeros más importantes
encontrados tanto en la vida animal como en la vegetal. Desde siempre el hombre ha
utilizado muchos de estos polímeros como materiales para hacer ropa, decoración,
herramientas, etc. Sin embargo, el origen de la industria de polímeros que conocemos
hoy en día se produjo en el siglo 19, gracias a importantes descubrimientos dentro de la
modificación de ciertos polímeros naturales, como la celulosa. El uso de polímeros
sintéticos y naturales como estabilizadores de sistemas coloidales (dispersiones,
microemulsiones, etc.) juega en nuestros días un papel importante. Los polímeros
utilizados como aditivos, pueden ser aplicados en preconcentraciones y deshidratación
de suspensiones dentro de procesos minerales, tratamiento de aguas residuales e incluso
los podemos encontrar dentro de la industria farmacéutica y alimentaria, donde su
importancia es debida a la procesabilidad y propiedades que ellos exhiben. El trabajo
que se presenta es orientado al desarrollo de técnicas de modelización, tanto analíticas
como computacionales, y su aplicación en la descripción (por medio de la formación de
bucles y colas) de la estructura de la capa de polímeros adsorbida en superficies
heterogéneas, siendo dicha capa de polímeros un factor importante en las propiedades
que este tipo de materiales presentan. Con este propósito, la metodología conocida
como Single Chain Mean Field, utilizada anteriormente tanto para el estudio de
agregados micelares como de polímeros anclados en superficies, ha sido modificada
para describir la adsorción de polímeros en superficies. Así se han podido calcular
numéricamente propiedades medibles experimentalmente como los perfiles de la
fracción en volumen de monómeros totales, además de los pertenecientes a los bucles y
colas, adsorbancia o el espesor de la capa adsorbida, para geometrías de la superficie
absorbente tanto plana como esférica (partículas coloidales). En su comparación con
otras metodologías, ya establecidas para la simulación numérica dentro de la física de
polímeros, la aplicación de esta nueva versión del Single Chain Mean Field (SCMF)
ha resultado ser más eficiente debido a un mejor muestreo del espacio de
configuraciones de las cadenas poliméricas. De este modo, comparando los resultados
obtenidos a partir del SCMF, con aquellos obtenidos mediante técnicas de simulación
Monte Carlo o la teoría desarrollada en los años 80 por Scheutjens y Fleer (SCF), se ha
podido encontrar un buen acuerdo en las propiedades calculadas para el caso de la
adsorción en superficies planas. Debido a la dificultad intrínseca del estudio de la
adsorción en superficies curvadas, nuestros resultados son los primeros que presentan
predicciones cuantitativas sobre la estructura de la capa que se forma sobre una
partícula coloidal. Así hemos podido comprobar la dependencia de la estructura de la
capa de polímeros adsorbidos con el tamaño de la partícula sobre la que se encuentran
adsorbidos además de las longitudes características de las cuales depende. Finalmente,
en este trabajo se ha desarrollado, también, una teoría analítica para la descripción de la
mezcla polímero-coloide. De este modo, los resultados numéricos obtenidos con el
SCMF han podido ser comparados con dicha teoría, obteniendo, de nuevo, un buen
acuerdo y predecir, además, comportamientos colectivos como la formación de geles.

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Ghelawi, Mohamed Ali. "A physico-chemical analysis of irradiated dates (Phoenix dactylifera L.)." Thesis, University of Salford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360402.

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Sarkar, Amit Kumar. "Fullerenes and non-planar graphitic networks : a physico-chemical analysis." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387366.

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Guerreiro, A. "Rational analysis of physico-chemical parameters affecting recognition properties of molecularly imprinted polymers." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/11014.

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Molecularly imprinted polymers (MIPs) are new type of materials with tailor made molecular recognition sites. Despite their enormous potential in separations, sensing and pharmaceutical industry, MIPs have so far failed to achieve significant commercial application. This is in part due to lack of understanding of MIPs at a molecular level, strong binding site heterogeneity and poor compatibility with aqueous solvents. This work is aimed at improving overall MIP performance and quality, with special focus on the improvement of compatibility with aqueous environment. Compatibility with aqueous solvents was achieved by (i) employing a molecular modelling step prior to polynerisation, (ii) by studying the ionic properties of the polymer and (iii) by analysis of the influence of different polymerisation conditions. The study of the pressure and magnetic field effects on polymers allowed us to produce materials with increased stability, lower binding site heterogeneity and higher affinity, as compared to standard imprinted materials. To minimise site heterogeneity imprinted nanoparticles with ca. 90 kDa were produced using a living polymerisation method. The particles with essentially uniform population of binding sites were obtained by employing affinity chromatography with immobilised template. As a model system variety of drugs were imprinted with the polymers being able to discriminate between closely related structural analogues in aqueous media. This work had substantial effect on success of project Pisarro - Piezoelectric Sensing Arrays for Biomolecular Interactions and Gas Monitoring where range of imprinted polymers were designed with high affinity to drugs of abuse. Currently 1 work is in progress aimed at application of these materials in commercial sensors for forensic use.

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Guerreiro, António. "Rational analysis of physico-chemical parameters affecting recognition properties of molecularly imprinted polymers." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/11014.

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Molecularly imprinted polymers (MIPs) are new type of materials with tailor made molecular recognition sites. Despite their enormous potential in separations, sensing and pharmaceutical industry, MIPs have so far failed to achieve significant commercial application. This is in part due to lack of understanding of MIPs at a molecular level, strong binding site heterogeneity and poor compatibility with aqueous solvents. This work is aimed at improving overall MIP performance and quality, with special focus on the improvement of compatibility with aqueous environment. Compatibility with aqueous solvents was achieved by (i) employing a molecular modelling step prior to polynerisation, (ii) by studying the ionic properties of the polymer and (iii) by analysis of the influence of different polymerisation conditions. The study of the pressure and magnetic field effects on polymers allowed us to produce materials with increased stability, lower binding site heterogeneity and higher affinity, as compared to standard imprinted materials. To minimise site heterogeneity imprinted nanoparticles with ca. 90 kDa were produced using a living polymerisation method. The particles with essentially uniform population of binding sites were obtained by employing affinity chromatography with immobilised template. As a model system variety of drugs were imprinted with the polymers being able to discriminate between closely related structural analogues in aqueous media. This work had substantial effect on success of project Pisarro - Piezoelectric Sensing Arrays for Biomolecular Interactions and Gas Monitoring where range of imprinted polymers were designed with high affinity to drugs of abuse. Currently 1 work is in progress aimed at application of these materials in commercial sensors for forensic use.

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Al-Awad, Musaed Naser J. "Physico-chemical analysis of shale-drilling fluid interaction and its application in borehole stability studies." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1368.

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Shale is often the most difficult of all formations to maintain a stable wellbore in when drillincr ::> for oil and gas. Time and money spent overcoming this problem during drilling, together with overall reduced profit margins. has led the oil industry to devote considerable time and effort to solve the problem of unstable boreholes in shales. It has long been established that the moisture adsorption (or desorption) of shale rocks can be controlled by the salinity of drilling fluid. When compacted shale (under constant compaction stress) adsorbs moisture, its total volume increases and swelling strains develop. Developed swelling strains then become an integral part of the effective radial stress acting on the shale formation contributing to borehole failure. A mathematical model has been developed for predicting the swelling behaviour of shale when placed in contact with water under moderate pressures and the effect of the swelling on borehole (in)stability. The model is based on thermodynamic theory which suggests that fluid movement into or out of a shale is driven by an imbalance in the partial molar free energy of the shale and the contacting fluid. Conversion of the free energy of each system (fluid and shale) into "total swelling pressure" made it possible to model transient pressures and strains generated in shale. The analytical solution of the radial diffusivity equation is reduced to a simpler form for the model. The model was validated using equipment and experimental techniques which allow continuous monitoring of shale swelling as function of time and distance from the wetting end. It was found that increasing the compaction stress acting on the shale reduced the rate of swelling, and increasing the hydraulic pressure of the fluid on the shale's wetted surface increased the rate of swelling. This behaviour was adequately described by the model which therefore represents a new method for predicting shale swelling as function of time and radial distance under different environments. Swelling strains are then used to predict related changes in shale mechanical properties (failure criteria) and well (in)stability. Several well-site index tests have been developed to study shale-drilling fluid interaction at wellsite. These index tests can provide input data for the mathematical model. Drilling fluids can be screened for their ability to control shale swelling, thus minimising the risk of well bore instability.

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Porkert, Sebastian. "Physico-Chemical Processes during Reactive Paper Sizing with Alkenyl Succinic Anhydride (ASA)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-219620.

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Sizing (hydrophobization) is one of the most important process steps within the added-value chain of about 1/3rd of the worldwide produced paper & board products. Even though sizing with so-called reactive sizing agents, such as alkenyl succinic anhydride (ASA) was implemented in the paper industry decades ago, there is no total clarity yet about the detailed chemical and physical mechanisms that lead to their performance. Previous research was carried out on the role of different factors influencing the sizing performance, such as bonding between ASA and cellulose, ASA hydrolysis, size revision as well as the most important interactions with stock components, process parameters and additives during the paper making process. However, it was not yet possible to develop a holistic model for the explanation of the sizing performance given in real life application. This thesis describes a novel physico-chemical approach to this problem by including results from previous research and combining these with a wide field of own basic research and a newly developed method that allows tracing back the actual localization of ASA within the sheet structure. The carried out measurements and trial sets for the basic field of research served to evaluate the stock and process parameters that most dominantly influence the sizing performance of ASA. Interactions with additives other than retention aids were not taken into account. The results show that parameters, such as the content of secondary fibers, the degree of refining, the water hardness as well as the suspension conductivity, are of highest significance. The sample sets of the trials with the major impacting parameters were additionally analyzed by a newly developed localization method in order to better understand the main influencing factors. This method is based on optical localization of ASA within the sheet structure by confocal white light microscopy. In order to fulfill the requirements at magnification rates of factor 100 optical zoom, it was necessary to improve the contrast between ASA and cellulose. Therefore, ASA was pretreated with an inert red diazo dye, which does not have any impact on neither the sizing nor the handling properties of ASA. Laboratory hand sheets that were sized with dyed ASA, were analyzed by means of their sizing performance in correlation to measurable ASA agglomerations in the sheet structure. The sizing performance was measured by ultrasonic penetration analysis. The agglomeration behavior of ASA was analyzed automatically by multiple random imaging of a sample area of approx. 8650 µm² with a minimum resolution for particles of 500 nm in size. The gained results were interpreted by full factorial design of experiments (DOE). The trials were carried out with ASA dosages between 0% and 0.8% on laboratory hand sheets, made of 80% bleached eucalyptus short fiber kraft pulp and 20% northern bleached softwood kraft pulp, beaten to SR° 30, produced with a RDA sheet former at a base weight of 100 g/m² oven dry. The results show that there is a defined correlation between the ASA dosage, the sizing performance and the number and area of ASA agglomerates to be found in the sheet structure. It was also possible to show that the agglomeration behavior is highly influenced by external factors like furnish composition and process parameters. This enables a new approach to the explanation of sizing performance, by making it possible to not only examine the performance of the sizing agent, but to closely look at the predominant position where it is located in the sheet structure. These results lead to the explanation that the phenomenon of sizing is by far not a pure chemical process but rather a more physical one. Based on the gained findings it was possible so far to optimize the ASA sizing process in industrial-scale by means of ~ 50% less ASA consumption at a steady degree of sizing and improved physical sheet properties.

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Siegwein, Alexander Martin. "THE EFFECTS OF SOY PROTEIN ISOLATE ADDITION ON THE PHYSICO-CHEMICAL PROPERTIES OF GUMMI CONFECTIONS." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276883276.

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Holderer, Olaf-Notker. "Nano-structural and physico-chemical analysis of Pd-Sn colloidal solutions applied to the metallisation of polymers." Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0023/these.pdf.

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Le revêtement électrochimique de métaux sur des polymères est fréquemment réalisé dans de nombreuses applications industrielles. La surface du polymère doit pour cela subir un traitement d'activation. Dans une première étape, une fine couche de colloi͏̈des palladium-étain est déposée sur le polymère ; elle est suivie d'une étape d'échange qui consiste à échanger des atomes d'étain par des atomes de cuivre pour accroître la conductivité de surface et rendre alors possible l'électrodéposition d'un métal comme le cuivre par exemple. Les colloi͏̈des déposés sont produits dans une suspension acide. Leur taille est voisine de 2 nm et ils sont supposés avoir un cœur constitué d'un alliage Pd-Sn entouré d'une peau riche en étain. Le but de notre étude est d'approfondir la nature physico-chimique des suspensions colloi͏̈dales et des couches adsorbées en surface d'un polymère en combinant plusieurs techniques de caractérisation microstructurales fines comme la diffusion centrale de rayons X (SAXS), la cryo-microscopie électronique, la microscopie électronique à haute résolution (METHR), la spectroscopie de rayons X (EDX) et photoélectrons (XPS), la rétrodiffusion (RBS) et la spectroscopie de pertes d'énergie des électrons transmis (EELS). Les deux premières techniques ont donné des informations sur la valeur et la distribution des tailles des colloi͏̈des ainsi que sur la stabilité des solutions. La nature cristallographique des colloi͏̈des a été appréhendée par METHR tandis que la composition chimique à l'échelle atomique a été obtenue par EELS en mode nano-sonde. C'est ainsi que nous avons validé un enrichissement superficiel en étain des colloi͏̈des. Les analyses des couches déposées en surface des polymères après chacune des étapes du procédé de métallisation, ont permis d'appréhender l'évolution de la nano-structure et de la chimie des couches colloi͏̈dales au cours de leur élaboration
Electrochemical deposition of metals on polymer substrates is a widely used industrial application, for example in surface finishing. The polymer surface requires a pre-treatment in order to get activated. In a first step, a thin layer of palladium-tin nano-colloids is deposited on the surface, followed by a Cu-Sn exchange step, which enhances the conductivity and enables the electrodeposition of metals like Cu. The colloids deposited in the first step from an acid suspension are supposed to have a core, which consists of a Pd-Sn alloy and a stabilising shell of tin. The size of the colloids is ~2 nm. Aim of this study is to get a deeper insight into the nature of the colloidal suspension and the adsorbed surface layers by combining different experimental techniques for a chemical and structural analysis at the nanometer scale, such as small angle X-ray scattering (SAXS), X-ray photoelectron spectroscopy (XPS), Cryo-electron microscopy (Cryo-TEM), high resolution transmission electron microscopy (HRTEM), Rutherford Back-Scattering (RBS) and electron energy loss spectroscopy (EELS). The colloidal solution has been characterised by SAXS and Cryo-TEM, which allowed to determine the size of the colloids and to obtain information on the stability of the solution. The crystallographic structure of the colloids in suspension has been studied with HRTEM. EELS has been used to study the chemical composition of the colloids. By focussing the electron beam to sub-nanometric spot sizes it has been possible to get very local information on the elemental composition of the colloids and to evidence a slight Sn surface enrichment. The analysis of the surface layer after each of the different steps of the plating process allowed determining the nano-structure and chemistry of the adsorbed colloidal layer and its modification during the process

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Kodavali, Swathi Sree. "Physico-chemical properties, and water and oil uptake characteristics of novel, soy-based snacks processed using extrusion." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15055.

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Master of Science
Department of Grain Science and Industry
Sajid Alavi
Extrusion processing and frying are the two most commonly used methods to produce savory snacks. These snacks are mostly starch based and also contain high amounts of fat. Snacking percentage has increased drastically over the past few decades causing many health problems like obesity, hypertension and cardiovascular diseases. The overall objective of this study was to develop novel soy based savory snack that are high in protein and has less fat using both extrusion processing and frying. In the first part of this study both defatted soy (25-75%), wheat flour, monoglycerides (0.375 & 0.75%) and sodium bicarbonate (0 and 0.5%) were used to produce dense extrudates, which mimic the shape of lentils using pilot scale twin screw extruder. The extrudates were soaked in water and fried in corn oil to produced savory snacks. Soy influenced the water absorption during soaking and oil uptake during frying. The water uptake and % fat decreased with increase in soy and the amount of water uptake influenced the % fat absorption in the product. No significant differences were observed in overall acceptability and to summarize the increased protein and dense structure of the products challenge the texture of the products. In the second part of this research, dynamics of water and oil uptake were studied to see the role of texture modifiers like soy protein isolate (4, 8, & 12%), calcium bicarbonate (0.2, 0.4 & 0.6%) and pregelatinized wheat starch (4, 8, & 12%) on texture, water and oil uptake. Descriptive sensory analysis was conducted to study the sensory attributes of the products. Water holding capacity is influenced by the level of % starch addition and the degree of starch degradation during processing. Oil uptakes correlates to that of WHC and is also affected by the degree of gelatinization and crust formation. Degree of starch gelatinization, oil uptake and oil and starch matrix interactions had an impact on hardness. Among SPI, CaCO3 and PGWS, PGWS lowered the product hardness followed by SPI and CaCO3. Descriptive sensory results are similar to experimental results with PGWS samples having lower initial or substantial hardness and more oxidized or heated oil aroma and flavor.

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Boucherie, Nathalie. "La couleur dans la civilisation Nasca : production tinctoriale et picturale." Thesis, Lyon 2, 2014. http://www.theses.fr/2014LYO20041.

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Cette thèse se propose d’étudier de manière approfondie les matières colorantes et les techniques de coloration appliquées aux textiles de la culture Nasca. Cette civilisation préhispanique, sans écriture, s’est développée sur la côte sud du Pérou pendant environ neuf siècles (200 ans av. J.-C. ; 700 ans apr. J.-C.). Parmi sa culture matérielle, les textiles sont abondants et nombre d’entre eux sont de grande finesse avec des décors polychromes. La polychromie avait probablement une signification dans la cosmogonie Nasca et le textile est particulièrement chargé de sens dans la culture andine. Pourtant, les matériaux de la couleur demeurent un sujet encore méconnu dans le domaine textile. Il semblait donc intéressant d’identifier au moyen de méthodes physico-chimiques les matières colorantes utilisées par les artistes textiles Nasca. Pour ce faire, une enquête de terrain a été menée en amont pour récolter et identifier les sources colorantes susceptibles d’avoir été employées. Puis un corpus textile a été constitué avec des textiles inédits, issus de fouilles récentes menées sur les sites de Los Molinos, Estaqueria et Cahuachi, l’ancien centre politico-cérémoniel des Nasca. Quelques tissus d’autres cultures (Topará, Mochica et Nasca drivé) ont aussi été analysés pour établir des comparaisons.Les résultats fournissent de précieuses informations qui caractérisent la production tinctoriale et picturale des textiles Nasca. Au-delà de cet aspect technique, ces données sont utiles pour aborder sous un autre angle des problématiques archéologiques plus complexes notamment lorsque l’attribution culturelle des textiles est inconnue ou discutée, comme ceux de la péninsule de Paracas
This thesis’ aim is to propose an in-depth study of the dye-sources and dyeing and colouring techniques used for textiles in the Nasca civilization. This Pre-Columbian, pre-literate civilization flourished on the southern coast of Peru during some nine centuries (200 BC to 700 AD). In its material culture, textiles are very numerous and many of them are of outstanding quality, with a rich polychromatic ornamentation. Polychromy probably was of great significance among the Nasca and textiles seem to always have been of particular importance in Andean culture. Nevertheless, the material sources of the colours on these dyed and painted textiles have remained a comparatively poorly explored research field. It therefore appeared as a promising, innovative quest to try and identify the colouring matters used by Nasca textile artists, using state-of-the art physico-chemical analytical methods. To this effect, botanical and anthropological field missions were first conducted in order to identify and collect colouring sources that might have been employed by the Nasca dyers and textile painters. A corpus of archaeological textiles was assembled, selecting textiles discovered in the course of recent archaeological excavations on the sites of Los Molinos, Estaqueria and Cahuachi, the latter being the antique political and ceremonial centre of the Nasca civilization. A number of textiles from other cultures (Topará, Mochica and Nasca-derived) were also analyzed to allow comparisons.Our results bring precious new information on the production of dyes and paints on Nasca textiles. Allowing even further prospects than these important technical discoveries, they bring new light into complex archaeological issues, such as the cultural attribution of archaeological textiles whose provenance is unknown or disputed, which is the case for some textiles from the Paracas peninsula

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Birchill, Antony James. "The seasonal cycling and physico-chemical speciation of iron on the Celtic and Hebridean shelf seas." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/10236.

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Shelf seas represent an important source of iron (Fe) to the open ocean. Additionally, shelf seas are highly productive environments which contribute to atmospheric carbon dioxide drawdown and support large fisheries. The work presented in this thesis describes the seasonal cycle of Fe in the Celtic and Hebridean Shelf Seas, and determines the physico-chemical speciation of Fe supplied from oxic margins. The results from repeated field surveys of the central Celtic Sea showed a nutrient type seasonal cycling of dissolved Fe (< 0.2 µm; dFe), which is surprising in a particle rich shelf system, suggesting a balance of scavenging and remineralisation processes. Coincident drawdown of dFe and nitrate (NO3-) was observed during the phytoplankton spring bloom. During the bloom, preferential drawdown of soluble Fe (< 0.02 µm; sFe) over colloidal Fe (0.02-0.2 µm; cFe) indicated greater bioavailability of the soluble fraction. Throughout summer stratification, it is known that NO3- is drawn down to < 0.02 µM in surface waters. This study revealed that both dFe and labile particulate Fe (LpFe) were also seasonally drawn down to < 0.2 nM. Consequently, it is hypothesised that the availability of Fe seasonally co-limits primary production in this region. At depth both dFe and NO3- concentrations increased from spring to autumn, indicating that remineralisation is an important process governing the seasonal cycling of dFe in the central Celtic Sea. In spring, summer and autumn, distinctive intermediate nepheloid layers (INL) were observed emanating from the Celtic Sea shelf slope. The INLs were associated with elevated concentrations of dFe (up to 3.25 ± 0.16 nM) and particulate Fe (up to 315 ± 1.8 nM) indicating that they are a persistent conduit for the supply of Fe to the open ocean. Typically > 15% of particulate Fe was labile and 60-90% of dFe was in the colloidal fraction. Despite being < 50 km from the 200 m isobath, the concentration of dFe was < 0.1 nM in surface waters at several stations. Broadly, the concentration of nutrients in surface waters described an oligotrophic environment where co-limitation between multiple nutrients, including Fe, appears likely. Over the Hebridean shelf break, residual surface NO3- concentrations (5.27 ± 0.79 µM) and very low concentrations of dFe (0.09 ± 0.04 nM) were observed during autumn, implying seasonal Fe limitation. The dFe:NO3- ratio observed is attributed to sub-optimal vertical supply of Fe relative to NO3- from sub-surface waters. In contrast to the shelf break, surface water in coastal regions contained elevated dFe concentrations (1.73 ± 1.16 nM) alongside low NO3-. Seasonal Fe limitation is known to occur in the Irminger and Iceland Basins; therefore, the Hebridean shelf break likely represents the eastern extent of sub-Arctic Atlantic seasonal Fe limitation, thus indicating that the associated weakening of the biological carbon pump exists over a wider region of the sub-Arctic Atlantic than previously recognised. These key findings demonstrate that the availability of Fe to phytoplankton may seasonally reach limiting levels in temperate shelf waters and that oxic margins persistently supply Fe dominated by colloidal and particulate fractions to the ocean.

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Bikoro, Bi Athomo Arsène. "Analyse et valorisation des coproduits de la transformation industrielle de l’Acajou du Gabon (Khaya ivorensis A. Chev)." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3001.

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Au Gabon, la forêt recouvre plus de 85% du territoire soit environ 22 millions d’hectares de forêt ce qui représente un potentiel de plus de 400 millions de m3 de bois exploitables. Pour plus de 400 essences répertoriées exploitables, environ 80 sont exploitées, mais seules 13 font l’objet d’une exploitation à l’échelle industrielle. Le bois massif issu de l’exploitation forestière sous forme de grumes était, jusqu’à 2009, principalement destiné à l’exportation. Cependant depuis cette date, l’Etat Gabonais a décidé de développer son industrie, en imposant aux exploitants forestiers d’effectuer au minimum une première transformation dans le pays.Cette, réforme a conduit à l'augmentation de la transformation locale des grumes, et par conséquent à une hausse de la production de co-produits. Ces derniers représentent environ 50% de la masse initiale des grumes en ce qui concerne le sciage et environ 5% pour le déroulage. Les acteurs de la filière doivent actuellement faire face à une nouvelle problématique : un excès de produits connexes générés par la transformation locale du bois.Cette thèse a ainsi pour objectif général de proposer une démarche permettant de trouver des solutions de valorisation de ces co-produits, dont 85% sont actuellement brulés à ciel ouvert. Les co-produits de la transformation industrielle de l’acajou (Khaya ivorensis A. Chev) du Gabon ont été ainsi étudiés en trois phases. Un premier travail a été réalisé sur la caractérisation physico-chimique des extraits d’écorce, d’aubier et de bois de cœur d’acajou. Nous avons particulièrement travaillé sur les extraits phénoliques, dont les tanins. Ensuite, une voie de valorisation de ces composés a été étudiée : l’élaboration d’un adhésif à base de tanins d’acajou. Enfin, une autre piste de valorisation a été explorée : la mise au point d’un composite bois/plastique avec les co-produits de bois et les déchets issus de bouteilles plastiques.Les résultats des différents travaux effectués ont montré que les tanins d’acajou étaient riches en monomères de fisitinidine et de gallocatéchine. L’absence d’acide gallique sous forme libre a aussi été constatée. Par ailleurs, les colles à base de tanins d’acajou ont montré de bonnes caractéristiques thermiques. Enfin, le composite fabriqué a présenté des propriétés physico-mécaniques intéressantes qui permettent d’envisager une valorisation à plus grande échelle
The Gabon forest covers more than 85% of country, so about 22 million hectares of forest, which represents a potential of more than 400 million m3 of exploitable wood. For more than 400 species listed as exploitable, about 80 are exploitable, but only 13 are exploited on an industrial scale. Solid wood from logging in the form of logs was, until 2009, mainly intended for export. However, since that date, the Gabonese State has decided to develop its industry by requiring loggers to carry out at least a first transformation in the country.This reform has led to an increase in local transformation of logs, and therefore an increase in the production of co-products. The latter represent approximately 50% of initial log mass for sawing and around 5% for peeling. The actors of the sectors thus found themselves with the problem of an excess of products derived from the local processing of wood.General objective of this thesis is to propose an approach that makes it possible to find recovery solutions for these by-products, 85% of which are burnt in the open air.Co-products of the industrial transformation of mahogany (Khaya ivorensis A. Chev) from Gabon were thus studied in three phases. Initial work on the physicochemical characterization of bark, sapwood and heartwood of mahogany extracts has been carried out in general. We have particularly work on phenolic extracts, including tannins. Then, a way of valuing these compounds was studied: development of a tannin-based adhesive with mahogany tannins. Finally, another recovery avenue was explored: development of wood/ plastic composite with wood by-products and waste from plastic bottles.Results of various studies have shown that the mahogany tannins are rich in fisitinidin and gallocatechin monomers. The absence of free form of gallic acid was also noted. In addition, tannin-based adhesives of mahogany have shown good thermal characteristics. Furthermore, the composite has interesting physico-mechanical properties that would allow a possible valorization on a large scale

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Apreutesei, Mihai. "Temperature impact on thermal evolution of advanced PVD ceramic and metallic glass thin films : Physico-chemical and microstructural analysis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0009/document.

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Ces dernières années, les exigences de l'industrie dans le développement de nouveaux matériaux fonctionnels en mesure de résister aux conditions difficiles pendant l'opération d'usinage sont en constante augmentation. Les chercheurs doivent donc trouver de nouvelles solutions pour répondre aux besoins industriels de plus en plus sévères. L’utilisation de revêtement protecteur à la surface de l’outil de coupe est une solution très efficace. Des nouveaux matériaux architecturés sont étudiés pour leurs propriétés mécaniques, physiques et chimiques uniques assurant une résistance aux dégradations de surface dues à la corrosion, l'usure, le frottement; en particulier lorsque ces outils sont utilisés dans des environnements hostiles. Dans le cadre de cette thèse de doctorat, l'influence de la température sur la stabilité structurale de deux types de films minces déposés par PVD a été étudiée. Des films céramiques et de verre métallique ont été envisagés. Afin de préparer et optimiser ces films, le projet s’est axé sur l'étude de l'influence des conditions de dépôt sur les caractéristiques de croissance du film: composition chimique, structure, morphologie, puis sur les changements ultérieurs des principales propriétés des films minces, à savoir la résistance à l’oxydation et à la cristallisation lors de leur utilisation à hautes températures. Une démarche multi-échelle a été développée pour caractériser au mieux les couches. La première partie du travail est liée aux revêtements céramiques à base de CrN pour donner de nouvelles fonctionnalités et améliorer la surface des outils de coupe dans le but essentiel d'accroître leur durée de vie. La seconde partie du manuscrit est dédiée aux films minces de verres métalliques de Zr-Cu préparés par un procédé de co-pulvérisation magnétron PVD. Le but de cette partie consiste en l’étude de la relation entre la structure amorphe de ces films et leurs propriétés mécaniques. La conservation du caractère amorphe de ces films en température présente également un caractère essentiel. Les verres métalliques ont récemment attiré un fort intérêt car ils présentent des propriétés mécaniques intéressantes à température ambiante. Ils présentent, de ce fait, un grand potentiel pour des applications d'ingénierie en raison de leurs caractéristiques mécaniques et physico-chimiques uniques (haute limite élastique, résistance à la corrosion ...). Pour relier les propriétés mécaniques des couches à l’évolution de leurs microstructures, une partie importante de ce travail a porté sur l’observation de l’évolution de la couche au cours du chauffage au moyen de techniques de caractérisation in situ. Les films minces proposés au cours de ce travail peuvent être envisagées pour un large gamme d’application dans l’ingénierie de surface pour protéger les surfaces et améliorer la durée de vie des matériaux
In the recent years the industrial requirements to develop new functional materials able to overcome the severe conditions during machining operation are continuously increasing. Researchers then must find novel solutions to respond to their severe industrial requirements. To coat the tool surface with advanced coatings is the most efficient solution. New nanostructured materials may nowadays exhibit unique mechanical, physical and chemical properties ensuring notable degradation resistance where the surface protection of materials against corrosion, wear, friction or oxidation is a key issue, particularly when operating in hostile environments. Within the scope of this Ph.D. thesis the influence of the temperature on the structural stability of two different PVD ceramic and metallic glass thin films is proposed. The main goal consists in the development of two distinct classes of thin films, with a wide range of properties. In order to prepare these films, the project will be focused on the study on the influence of PVD deposition conditions in the particular film’s growth characteristics: chemical composition, structure, morphology and the subsequent changes in the main properties of the thin films, namely oxidation and crystallization resistance, especially. For that purpose we adopted the multiscale approach. The first part is related to the ceramic CrN-based coatings to give new functionalities and improve the tools’ surface with the primary aim to increase their lifetime. Secondly, new protective materials able to better protect the exposed surfaces against high temperature oxidation have been proposed, namely CrAlN and CrAlYN coatings as will be evidenced in this manuscript. The second part of the manuscript is dedicated to the innovative Zr-Cu thin films metallic glasses prepared by a PVD magnetron co-sputtering method with the objective to investigate the amorphization ability and their structural properties. Their excellent properties at room temperature have recently attracted attention as a new class of materials with great potential for engineering applications due to unique mechanical and physico-chemical characteristics (high elastic strain limit, corrosion resistance…). Finally, an important approach during the course of this thesis was the real time observation of the structure and surface modifications during heating by means of in situ methods. The thin films proposed during the course of the work could be straightforward used as surface engineering solutions to protect and extend the lifetime of the materials and components

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Afrassiabian, Zahra. "Multiscale investigation of caking phenomenon of lactose powders : from physico-chemical aspects to industrial applications." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2475/document.

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Cette thèse porte sur le problème fondamental du mottage des poudres suite aux mécanismes de transition de phase. Le projet vise à étudier l'impact des facteurs intrinsèques (structure moléculaire des matériaux, propriétés physiques et/ou physicochimiques, etc.) ou des facteurs environnementaux (conditions de stockage ou paramètres de procédé) sur la stabilité de la structure des poudres. Plus précisément, notre étude a mis en évidence le rôle prépondérant du phénomène de cristallisation et des transitions entre les différents polymorphes du lactose. L'accent a été mis sur le rôle des phénomènes de cristallisation et de la transition de phase dans l'apparition du mottage des poudres de lactose. Deux cas ont particulièrement retenu notre attention: (1) des poudres de lactose monohydrate contenant une fraction de particules amorphes et (2) des échantillons de poudre anhydre composés des anomères α et β du lactose. Dans les deux cas, le mottage a été induite par l'exposition des échantillons à l'air humide, soit dans un dispositif de sorption dynamique de vapeur (SPS), soit par des tests accélérés utilisant deux appareils conçus et réalisés dans notre laboratoire (CLAIR & OLAF). Nos résultats ont montré que, dans les deux cas, la principale cause de prise en masse était la formation de lactose monohydrate, qui est la forme la plus stable parmi tous les polymorphes de lactose. Cependant, les mécanismes élémentaires, les étapes limites et la cinétique du processus de transformation étaient différents dans chaque cas. Les paramètres les plus déterminants étaient l’humidité relative et la température alors que la pression n’a pas eu d’effet significatif. La résistance mécanique des échantillons mottés était étroitement liée au taux et à la cinétique de cristallisation. Enfin, des simulations numériques basées sur la méthode des éléments discrets (DEM) de la résistance mécanique des échantillons mottés ont été réalisées. Le modèle permet de décrire le comportement des échantillons mottés soumis à des contraintes mécaniques de compression ou de traction
This PhD study focuses on the fundamental problem of powder caking due to phase transition mechanisms. The project aims to study the impact of intrinsic factors (molecular structure of materials, physical and/or physicochemical properties, etc.) or environmental factors (storage conditions or process parameters) on the stability of the structure of powders. More precisely, our study has highlighted the preponderant role of the crystallization phenomenon and the transitions taking place between the different polymorphs of lactose. Emphasis was placed on the role of crystallization phenomena and phase transition on the advent of lactose powder caking. Two cases attracted particular attention: (1) lactose monohydrate powders containing a fraction of amorphous particles and (2) anhydrous powder samples composed of ð and anomers of lactose. In both cases, the caking was induced by exposure of the samples to moist air, either in a Dynamic Vapor Sorption device (SPS) or in accelerated caking tests using two home-made equipment (CLAIR & OLAF). Our results showed that in both cases, the main cause of caking was the formation of lactose monohydrate, which is the most stable form among all lactose polymorphs. However, the elementary mechanisms, the limiting steps and the kinetics of the transformation process were different in each case. The more influencing parameters were the relative humidity and the temperature whereas the pressure has no significant effect. The yield stress of caked samples was closely linked with crystallization extent and kinetics. Finally, numerical simulations based on Discrete Element Method (DEM) of mechanical resistance of caked samples were performed using the "beam model". The model allows describing the behavior of the caked samples subjected to compressive or tractive mechanical stresses

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Souza, Alan Kardec de. "Características microbiológicas, físico-químicas e sensoriais do leite de cabra submetido à pasteurização e ao congelamento comercializados em Alfenas." Universidade Jose do Rosario Vellano, 2012. http://tede2.unifenas.br:8080/jspui/handle/jspui/131.

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Made available in DSpace on 2016-05-02T13:55:33Z (GMT). No. of bitstreams: 1 AlanKardecdeSouza-dissertacao.pdf: 422059 bytes, checksum: ea2c6f1ec1d26f3446d1eeee444a6292 (MD5) Previous issue date: 2012-08-24
Goat's milk is a complete food, rich in proteins, fats, vitamins and minerals. Having very small lipid molecules, it is highly digestible when compared to other types of milk. One of the great challenges for the popularization of goat milk is that many potential consumers reject it because of its odor, flavor and high price when compared to pasteurized cow milk. This study aimed at analyzing the quality of the milk commercialized in Alfenas, MG, Brazil and evaluating the effect of pasteurization and freezing on its microbiological, physico-chemical and sensory characteristics. During 270 days, 3 batches of raw, pasteurized, and pasteurized and frozen goat milk were analyzed. Each batch was assessed every 90 days. The data were submitted to ANOVA and the Tukey test. The results showed that the slow pasteurization was effective in improving the microbiological quality of the milk, while no change was found in freezing it for 90 days. The physico-chemical and sensory characteristics of the milk was not changed by pasteurization and 90-day freezing. It was concluded that the goat milk commercialized in Alfenas, MG, Both pasteurized and pasteurized and frozen, have microbiological, physico-chemical and sensory quality within the standards established by law.
O leite de cabra é um alimento completo, rico em proteínas, gorduras, vitaminas e sais minerais, possui moléculas de gordura de tamanho reduzido, apresentando alta digestibilidade comparado aos demais tipos de leites. Um dos maiores desafios para a popularização do leite de cabra é a grande rejeição por parte do público consumidor em potencial, devido ao forte odor, sabor e preço elevado comparado ao leite de vaca pasteurizado. Este trabalho objetivou analisar a qualidade do leite de cabra comercializado na cidade de Alfenas-MG e avaliar o efeito da pasteurização e do congelamento sobre suas características microbiológicas, físico-químicas e sensoriais. Durante 270 dias, foram realizadas análises microbiológicas, físico-químicas e sensoriais de 3 lotes de leite de cabra cru, pasteurizado e pasteurizado e congelado. Cada lote foi analisado a cada 90 dias. Os dados obtidos foram submetidos à análise de variância e teste de Tukey. Verificou-se que a pasteurização lenta foi eficiente para melhorar a qualidade microbiológica do leite e que o congelamento por 90 dias não a alterou. As características físico-químicas e sensoriais não foram alteradas pela pasteurização e nem após o congelamento por 90 dias. Concluiu-se que o leite de cabra, pasteurizado e pasteurizado e congelado, comercializado na cidade de Alfenas-MG possui qualidade microbiológica, físico-química e sensorial dentro dos padrões estabelecidos pela legislação.

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Zombré, Wendlamita. "Durabilité des matériaux composites dans un environnement Génie Civil : expérimentation multi-échelle et analyse statistique." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1106/document.

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Notre thèse s’insère dans le cadre du projet ANR Micro « Matériaux Innovants Composites pour la Réparation d'Ouvrages : Approche fiabiliste du dimensionnement pour leur requalification et la prédiction de leur durabilité » L'objectif principal de la thèse est d’appréhender le problème de la durabilité par une approche expérimentale phénoménologique multi-échelle et de proposer des modèles de durée de vie au sens probabiliste. Le matériel d’étude est un carbone/époxy bidirectionnel non équilibré en masse (70% /30%) réticulé à l’ambiante et mis en œuvre par moulage au contact. Six vieillissements hygrothermiques obtenus par croisement entre les températures (20°C, 40°C et 60°C) et les humidités (50%, 75% et immersion) à diverses échéances ont été réalisés au cours de l’étude. Après identification des divers indicateurs, nous avons réalisé des analyses physico-chimiques (absorption-désorption, DSC, TMA, Infrarouge, DMA et Tomographie) ainsi qu’un suivi des caractéristiques mécaniques (traction, cisaillement interlaminaire, pull-out et double cisaillement) afin de définir les différents mécanismes de dégradation des propriétés mécaniques et physicochimiques des matrices polymères, des interfaces fibres–matrice, des joints de colle à l’interface composite-structure renforcée au cours du vieillissement pour le système classique Carbone/Epoxy. Ces indicateurs ont été analysés statistiquement afin de valider plus rigoureusement les tendances qui ont été observées. Le suivi des indicateurs mécaniques de performance par le vieillissement accéléré a été réalisé puis comparé à 1 an de vieillissement naturel. L’antagonisme des différents mécanismes de dégradations a été mis en évidence dans le cas de traction simple et du cisaillement interlaminaire. Il ressort que la plastification est le mécanisme qui affecte le plus les performances des composites carbone/époxy. Pour les températures élevées, il semble que la post-réticulation en densifiant le réseau a amélioré les cohésions interfaciales, ce qui a inhibé l’impact de la dégradation thermique sur les performances mécaniques. En comparant avec le vieillissement naturel, on a pu remarquer que le vieillissement en milieu aqueux était plus dégradant de façon générale et accélérait convenablement la dégradation en milieu naturel. En particulier, les tendances observées ne suivent pas des évolutions qui permettent d’apprécier trivialement la chute de performance par des modèles de prédiction. La qualité de l’adhérence composite/béton a été évaluée par des tests d’arrachement. Les fortes disparités entre les résultats rendent les interprétations délicates. Mais il a été mis en évidence que la post-réticulation semblent améliorer la cohésion tandis que la plastification est très néfaste pour la stabilité du joint de colle accélérant de façon excessive la dégradation en comparaison avec le vieillissement naturel. Cette instabilité a également été prouvée par les tests de double cisaillement où le délaminage était observé dès les premières échéances de vieillissement. La dernière partie du travail a consisté à proposer un traitement statistique des données pour valider tout d’abord les tendances observées expérimentalement, apporter plus d’informations et discuter sur le choix des modèles de prédiction. Bien que très apprécié par la communauté, l’utilisation des modèles physiques n’est pas systématique car elle suppose des performances dégénératives, ce qui en pratique n’est pas le cas. Une approche physique a été proposée sur la base de données épurée afin de respecter les conditions d’écriture du modèle. Le modèle choisi pour prédire la résistance ultime en traction est conservateur mais a le mérite d’être utilisable pour des études de fiabilité. L’enrichissement bayésien pourra être utilisé pour démontrer l’avantage qu’il peut conférer dans les études de fiabilité
Our thesis is part of this MICRO project "Innovative Composite Materials for the Repair of Structures: Reliability approach of the dimensioning for their requalification and the prediction of their durability". Final objective of the thesis is to understand the problem of sustainability through a multi-scale phenomenological experimental approach and to propose probabilistic life-time models. So, we defined the methodology of our study, as well as the methods, materials and analysis techniques. The study material is a non-equilibrium (70% / 30%) unbalanced bidirectional carbon / epoxy that is crosslinked at room temperature and made by hand layup process. Six hygrothermal aging obtained by crossing between temperatures (20°C, 40°C and 60°C) and humidities (50%, 75% and immersion) at various times were carried out during the study. After identifying the various indicators, we carried out physicochemical analyzes (absorption-desorption, DSC, TMA, Infrared, DMA and Tomography) as well as a follow-up of the mechanical characteristics (tensile, interlaminar shear, pull-out and double shear). These indicators were analyzed statistically to more rigorously validate the trends that were observed. The monitoring of mechanical performance indicators by accelerated aging was carried out and then compared to 1 year of natural aging. The antagonism of the various mechanisms of damage has been demonstrated in the case of simple traction and interlaminar shear. It appears that plasticization is the mechanism that most affects the performance of carbon / epoxy composites. For high temperatures, it appears that post-cure by densifying the network has improved interfacial cohesion, which has inhibited the impact of thermal degradation on mechanical performance. Comparing with natural aging, it was noted that aging in an aqueous condition was more generally degrading and aqueous conditions accelerated well the degradation in a natural environment. In particular, the trends observed do not follow evolutions that permit to write simplified prediction models. The quality of the composite / concrete adhesion was evaluated by pull-out tests. The strong disparities between the results make the analysis delicate. But it has been shown that the post-cure seems to improve the cohesion whereas the plasticization is very harmful for the stability of the bonded joints accelerating excessively the degradation in comparison to the natural aging. This instability has also been proven by the double shear tests where the delamination was observed from the first maturities of aging. The anchor length is reduced and a time-sensitive model has been proposed for the selected aging condition (60°C-immersion). On the other hand, this plasticization softens the failure due to the increased deformability of the joint. In this environmental condition, the monitoring of the elastic limit stress seems to be a relevant indicator for the monitoring of the durability because it simulates the natural aging with reasonable differences. The last part of our work consisted in the proposal of a statistical treatment of the data in order to validate firstly the trends observed experimentally, to bring more information and to discuss on the choice of the models of prediction. Although, physical model is very appreciated by the community, it is not systematically applicable. Indeed, it assumes degenerative performance, which in practice is not the case. A physical approach has been proposed on the refined database in order to respect the writing conditions of the model (degenerative trends). The model chosen to predict the ultimate tensile strength is conservative but applicable for reliability studies. Bayesian enrichment can be used to demonstrate the advantage it can confer in reliability studies

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Holderer, Olaf-Notker Esnouf Claude. "Nano-structural and physico-chemical analysis of Pd-Sn colloidal solutions applied to the metallisation of polymers alyse nano-structurale et physico-chimique de solutions colloïdales Pd-Sn appliquée à la métallisation des polymères /." [S.l.] : [s.n.], 2002. http://csidoc.insa-lyon.fr/these/2002/holderer/index.html.

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Nyembwe, Patricia. "Sensory and physico-chemical analysis of roasted marama beans [Tylosema esculentum (Burchell) A. Schreiber] with specific focus on compounds that may contribute to bitterness." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/79294.

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Marama bean [Tylosema esculentum (Burchell) A. Schreiber] is an underutilized legume which grows wild in selected part of southern Africa and forms part of the diet for the indigenous population in this area. Marama bean seeds are not eaten raw but after roasting they have a delicious nutty flavour. A bitter taste develops depending on the extent of heating. Heat treatment by roasting marama beans at 150 °C for 20 min inactivates anti-nutritional factors particularly trypsin inhibitor. The bitter taste can limit the utilisation and consumption of this pulse. Research is lacking on the compounds that could be responsible for the bitter taste in marama beans. Different chemicals including phenolic compounds and saponins contribute to bitterness in many edible legumes. An increase in the quantity of the bitter substances in roasted marama bean might contribute to more bitter taste. In this study sensory profiles and potential bitter substances of marama bean cotyledons were investigated as a function of roasting time. Marama beans were roasted at 150 °C for different time periods 20, 25 or 30 min. Three pastes were prepared from the roasted cotyledons; paste20, paste25 and paste 30. Eight samples of water extracts were prepared from full fat and defatted flours from roasted and unroasted marama cotyledons. Descriptive sensory evaluation was conducted with a trained panel to rate the intensity of aroma and flavour attributes of marama pastes and bitterness of water extracts. Marama pastes were subjected to colour measurement, lightness (L*), red/green characteristics (a*) and blue/yellow characteristics (b*). The total phenolic and saponin contents of marama water extracts were determined. The phenolic profile were analysed by reverse phase-high performance liquid chromatography (RP-HPLC). The paste20 was lighter and the least bitter while paste30 was dark-coloured and the most bitter. The water extracts prepared from unroasted flours were rated the least bitter while the water extract prepared from defatted flour made from marama bean roasted for 30 min was the most bitter. Roasting of marama seeds resulted in significant increases in its water soluble phenolic content. The concentration of total phenolics in the seeds roasted for longer time periods was higher. The major extractable phenolic acids present in marama water extracts were found to be gallic and protocatechuic acids, the concentrations of which increased as a function of roasting time and may be the cause of more intense bitterness. Marama beans have saponins content varying from 84.4 mg/100 g in raw flour to 94.9 mg/100 g in roasted flour. The different concentrations of saponins in water extracts prepared from roasted and unroasted marama flour (55-62 mg/L) were higher than the reported bitter threshold value for saponins in water (2-12 mg/L). Thus, saponins in marama beans possibly also contributed to more bitterness. Roasting time and temperature combinations shoud be considered when processing marama beans for food products. At 150 ˚C roasting temperature, marama beans should not be roasted for more than 20 min to avoid bitterness, colour darkening as well as development of a burnt flavour.
Dissertation (MSc)--University of Pretoria, 2014.
Food Science
MSc
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Matlala, Malebo Desnet. "The use of diatoms to indicate water quality in wetlands : A South African perspective / by Malebo D. Matlala." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4410.

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In a semi-arid country like South Africa, the availability and quality of water has always played an important part in determining not only where people can live, but also their quality of life. The supply of water is also becoming a restriction to the socio-economic development of the country, in terms of both the quality and quantity of what is available. Thus different monitoring techniques should be put in place to help inform the process of conserving this precious commodity and to improve the quality of what is already available. Water quality monitoring has traditionally been by the means of physico-chemical analysis; this has more recently been augmented with the use of biomonitoring techniques. However, since the biota commonly used to indicate aquatic conditions are not always present in wetlands; this study tested the use of diatoms as bio-indicators in wetlands. Diatom samples were collected from thirteen wetlands in the Western Cape Province, and cells from these communities were enumerated and diatom ?based indices were calculated using version 3.1 of OMNIDIA. These indices were useful for indicating water quality conditions when compared to the measured physico-chemical parameters. In addition, most diatom species found were common to those found in riverine environments, making the transfer of ecological optima possible. The objective of the study was to provide a preliminary diatom-based index for wetlands, however, given the relatively small study area and the strong bias towards coastal wetlands it was deemed inadvisable to construct such an index, instead several indices are recommended for interim use until further research that more comprehensively covers wetlands in South Africa has been conducted. It is thus the recommendation of this study that more data is collected for comparison to other wetlands and that in the interim, indices such as SPI be applied for routine biomonitoring of these environments.
Thesis (M.Sc. (Botany))--North-West University, Potchefstroom Campus, 2010.

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23

Essandoh, Ernest. "Structural studies of organic crystals of pharmaceutical relevance : correlation of crystal structure analysis with recognised non-bonded structural motifs in the organic solid state." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4444.

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Pharmaceutical solids tend to exist in different physical forms termed as polymorphs. Issues about pharmaceutical systems are mainly concerned with the active ingredient's physico-chemical stability and bioavailability. The main aim of this study is to investigate the non-bonded interactions in pharmaceutical solids that govern the physical pharmaceutics performance of such materials and through the use of structural techniques and correlation of these results with crystal structural database to establish the presence of physical motifs in selected systems. Structural motifs were identified by the use of single crystal and crystal packing analysis on diverse range of pharma-relevant materials including chalcones, cryptolepines, biguanides and xanthines. These selected systems were validated using functional group and molecular analysis and correlating them to the Cambridge Structural Database. Crystallization studies are done on these selected systems as well as exploiting those using synthetic analogues. A total of 51 crystal structures were investigated including 16 new structure determinations. Addition synthesis of new xanthines to investigate novel intermolecular patterns was also undertaken. The understanding and exploitation of intermolecular interactions involving hydrogen bonds and coordination complexation during packing can be used in the design and synthesis of solid state molecular structures with desired physical and chemical properties.

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24

Hervatin, Heloisa Litholdo. "Avaliação microbiologica e fisico-quimica do polen apicola in natura e desidratado sob diferentes temperaturas." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254730.

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Orientador: Lucia Regina Durrant
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O pólen apícola é a aglutinação do pólen presente nas flores coletados pelas abelhas operarias, e depositados na entrada da colméia. O estudo visou avaliar a qualidade microbiológica e físico-química do pólen IN NATURA e do submetido a diferentes processos de secagem, simulando as condições de processamento do produto comercializado. Também avaliou as amostras adquiridas no comercio do estado de São Paulo. Registrou-se a escassez das pesquisas sobre a qualidade microbiológica do pólen apícola. Primeiramente a pesquisa, analisou amostras de pólen apícola obtidas através de coletores instalados nas colméias pertencentes ao apiário experimental do Pólo Regional de Desenvolvimento Tecnológico dos Agronegócios do Vale do Paraíba, localizado em Pindamonhangaba-SP, pertencente à Agência Paulista de Tecnologia dos Agronegócios. A coleta ocorreu nos intervalos de 24horas, 48horas e 72horas, objetivando a presença e/ou quantidade de microrganismos patogênicos no pólen com relação ao tempo de permanência do produto no campo. As amostras foram congeladas por 48horas, e submetidas a dois processos de secagem (circulação de ar em sistema aberto a 40-42°C e sistema de circulação de ar fechado a 30°C). Foram realizadas as análises físico-químicas para os parâmetros de pH, umidade e atividade de água e as microbiológicas com avaliação de Bacillus cereus, Estafilococos coagulase positiva, coliformes a 45°C, Escherichia coli, Salmonella sp, bolores e leveduras, além de microrganismos sulfitos redutores. Amostras de pólen apícola desidratado foram adquiridas no mercado vajerista do Estado de São Paulo, com registro no Serviço de Inspeção Federal (SIF), submetidas aos mesmos parâmetros. Através dos cálculos estatísticos observaram-se possíveis diferenças e/ou correlações existentes entre os parâmetros analisados (microbiológicos, físico-químicos) para os tratamentos propostos (frequência de coleta e processos de desidratação). Verificou-se que as amostras analisadas, as IN NATURA e as desidratadas, mostraram-se isentas dos principais patógenos como Salmonella sp e Estafilococos coagulase positiva, porém, a população de bolores e leveduras foi relativamente elevada. Podendo concluir que os bolores e leveduras são os parâmetros microbiológicos mais significativos para o pólen apícola, seguido por Bacillus cereus e por bactérias coliformes totais, sendo parâmetros que devem ser introduzidos na legislação; além do processo de desidratação normalmente utilizado para pólen, não reduzir a população fúngica. Com base na Legislação atual para padrões microbiológicos em alimentos, considerando o grupo da granola, todas as amostras analisadas, encontram-se dentro dos padrões estabelecidos. Bolores e leveduras não estão incluídos na Legislação do MAPA. A época do ano teve influência na contaminação de Bolores e Leveduras, paralelamente com o tempo de permanência do pólen no campo, sendo indicada a coleta do material a cada 24horas. Assim os processos de secagem devem ser otimizados para permitirem a obtenção de produto livre de contaminantes microbiológicos; juntamente com a higienização do material nas diferentes etapas de produção e processamento do pólen, com foco na busca de materiais que substituam a madeira que é extremamente porosa, de forma a permitir higienização adequada e satisfatória. Outro parâmetro a ser considerado é a embalagem para o produto que merece atenção de especialistas nesta área
Abstract: The bee pollen is the agglutination of pollen present in flowers collected worker bees, and deposited at the entrance of the hive. The study aimed to evaluate the microbiological quality and physico-chemistry of the pollen in nature and subject to different processes of drying, simulating the processing conditions of the product sold. Also evaluated the samples acquired in the trade of the state. We have registered the scarcity of research on the microbiological quality of bee pollen. First the research, analyzed samples of bee pollen obtained from collectors installed in the experimental apiary hives belonging to the Regional Technology Development Center of Agribusiness of the Paraíba Valley, located in Pindamonhangaba-SP, belonging to the Agency of Technology Agribusiness Paulista. Frequency of collection in intervals of 24 hours, 48 hours and 72 hours, to the presence and/or amount of pathogenic microorganisms in pollen with the time of product in the field. The samples were frozen by 48 hours, and subjected to two drying processes (movement of air in the open system 40-42°C and a system of closed circulation of air at 30°C). Performed the analysis for the physical-chemical parameters of pH, humidity and water activity and with the microbiological assessment of Bacillus cereus, Coagulase positive Staphylococci, coliforms at 45°C, Escherichia coli, Salmonella, molds and yeasts, and micro sulphites reducing. Acquired samples of dried bee pollen market of the State of São Paulo, with registration at the Federal Inspection Service (SIF), subject to the same parameters. Through statistical calculations were observed possible differences and/or correlations between the analyzed parameters (microbiological, physico-chemical) for the proposed treatments (frequency of collection and processes of dehydration). It was found that the samples analyzed, the IN NATURE and dehydrated, were free of major pathogens such as Salmonella and Coagulase positive Staphylococci, however, the population of yeasts and molds is relatively high. May conclude that the yeasts and molds are the most significant microbiological parameters for the bee pollen, followed by Bacillus cereus bacteria and total coliforms, and parameters to be introduced into legislation, in addition to the dehydration process typically used for pollen, is not able to eliminate fungal its population, based on current legislation for microbiological standards in food, considering the group of granola, all the samples, are within the standards set. Yeast and molds are not included in the legislation of the MAP. The time of year influences the contamination of molds and yeasts, along with the time of pollen in the field, being given the collection of material every 24 hours. Thus the process of drying must be optimized to allow the achievement of product free of microbiological contaminants, together with the cleaning of equipment in various stages of production and processing of pollen constantly, with a focus in the search for materials to replace the wood that is extremely porous to enable proper cleaning and satisfactory. Another parameter to be considered is the packaging for the product deserves the attention of specialists in this area
Mestrado
Mestre em Ciência de Alimentos

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25

Carvalho, Catharina Calochi Pires de [UNESP]. "Linguiça cuiabana: histórico e aspectos tecnológicos de fabricação." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/88387.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A linguiça cuiabana tem grande aceitação no município de São José do Rio Preto-SP e regiões adjacentes. Originalmente é constituída de carne bovina (corte traseiro), leite, cebolinha, pimenta bode, pimenta do reino, alho e sal refinado. Atualmente, encontramos no comércio diversos tipos de linguiça cuiabana, diferenciadas por condimentos, queijos, cortes musculares ou por espécies animais (suína, bovina, frango). No presente trabalho, juntamente com seu levantamento histórico, estudaram-se as características tecnológicas/ sensoriais da linguiça cuiabana. Foi realizado o processamento sob condições assépticas, de 4 formulações da linguiça tipo cuiabana, variando a principal matéria-prima utilizada (carne bovina, frango, suína). No processamento, as matérias-primas (bovina, frango e suína) foram cortadas em cubos que, juntamente com outros ingredientes (alho, queijo, pimenta e cebolinha), foram pesados e homogeneizados. A massa resultante foi deixada em repouso sob refrigeração por 24 horas para melhor desenvolvimento do sabor. Após descanso da massa, foi realizado o embutimento em tripas naturais. A partir destas amostras foram realizadas a caracterização do perfil físico-químico e avaliação sob refrigeração, ao longo de 7 dias de armazenamento por meio de análises microbiológicas (coliformes totais e termotolerantes (fecais), clostrídrios sulfito redutores, Salmonella spp., Staphylococcus coagulase positiva), pH, TBA. Por fim, a avaliação sensorial e estatística das diferentes linguiças tipo cuiabana processadas em laboratório. Os resultados mostraram que as variações ao longo do tempo na formulação das linguiças cuiabanas são fatores positivos, ficando evidente que as transformações são bem mais aceitas que a precursora, o que possivelmente ocorreram em função da demanda do mercado.
The cuiabana sausage has wide acceptance in the municipality of Sao Jose do Rio Preto and surrounding regions. Originally, it consisted of beef (cut back), milk, chives, goat pepper, black pepper, garlic and salt. Currently, various types of cuiabana sausage are found in trade and they are distinguished by spices, cheeses, muscle cut or animal species (bovine, chicken and swine). In this paper, along with a historical survey, we studied the technical/ sensory characteristics of cuiabana sausage. Processing was performed under aseptic conditions for 4 formulations of sausage type cuiabana, varying the main raw material (bovine, chicken and swine). In processing, the raw meat (beef, chicken and pork) was cut into cubes, which together with other ingredients (garlic, cheese, pepper and chives), were weighed and homogenized. The resulting mass was subjected to refrigeration for 24 hours in order to develop better. After the dough we rested, the inlay was inserted in natural casings. These samples were used to characterize both the physical-chemical profile and also the evaluation under refrigeration, for over a 7 days-storage in order to assess microbiological contamination (total coliforms and thermotolerant (fecal), sulphite reducing clostrídrios, Salmonella spp. , Staphylococcus coagulase positive), pH, TBA. Finally, the sensory evaluation and statistics of the different types of cuiabana sausage processed in the laboratory were performed. The results showed that changes over time in the formulation of cuiabana sausages are positive factors, demonstrating, thus, that the changes are much more accepted than the precursor, which possibly occurred as a function of market demand.

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26

Bera, Alexandre. "Composição físico-química e nutricional do mel adicionado com própolis." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-03072009-104257/.

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O presente estudo teve, como objetivo principal, a determinação da composição físico-química e nutricional de onze amostras de méis com própolis comercializados no Estado de São Paulo, de acordo com as metodologias analíticas da legislação brasileira vigente (Instrução Normativa nº11 de 20 de outubro de 2000), que segue os métodos preconizados pelos Codex Alimentarius Commission (CAC), 1990 e Association of Official Analytical Chemists (AOAC), 1990). Amostras de mel puro e de própolis foram usadas como referência. Os resultados mostraram que os mesmos métodos usados para o controle de qualidade do mel puro (umidade, HMF, açúcares redutores, sacarose aparente, cinzas, acidez livre, sólidos insolúveis em água) foram adequados para o controle de qualidade do mel com própolis, exceto pela analise de atividade diastásica, que precisou de uma adaptação metodológica. A análise de minerais demonstrou que essas amostras não são fontes de ferro, magnésio, zinco e cálcio. A própolis adicionada ao mel aumentou o seu valor energético comparado com o mel puro. Cinco das onze amostras analisadas não apresentaram, na sua rotulagem, os valores nutricionais como recomenda a legislação. É indicada a necessidade de uma fiscalização mais rigorosa, assim como uma legislação específica para o controle de qualidade destes produtos.
The present work has, as its main objective, to determine the physico-chemical and nutritional composition of commercial samples of propolis added to honey from São Paulo State. Eleven honey-propolis samples were analyzed, according to the methods established by the Brazilian Law (Instrução Normativa n.11 de 20 de outubro de 2000) which recommends the same methods established by Codex Alimentarius Commission (CAC) and the Association of Official Analytical Chemists (AOAC, 1990). The results showed that the same methods used for pure honey quality control (moisture, HMF, reducing sugars, apparent sucrose, ash, free acidity, insoluble solids in water) except for the diastase activity which had to be adapted, can also be used for the honey-propolis quality control. The mineral analyses results showed that the samples were not a good source for iron, magnesium, zinc and calcium. Honey has its energy value enhanced by the addition of propolis if compared with pure honey. As five of the eleven samples analyzed did not have the nutritional values information on the labels as it is mandatory by the Brazilian Legislation, a more rigorous inspection and even a specific law should be established for the quality control of those products.

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27

Eberle, Alexander Richard [Verfasser], and Wolfgang [Akademischer Betreuer] Schmahl. "Growing low-dimensional supramolecular crystals via Organic Solid-Solid Wetting Deposition : physico-chemical basis, structure analysis, and doping of graphene / Alexander Richard Eberle ; Betreuer: Wolfgang Schmahl." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/119342321X/34.

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28

Carvalho, Catharina Calochi Pires de. "Linguiça cuiabana : histórico e aspectos tecnológicos de fabricação /." São José do Rio Preto : [s.n.], 2009. http://hdl.handle.net/11449/88387.

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Resumo: A linguiça cuiabana tem grande aceitação no município de São José do Rio Preto-SP e regiões adjacentes. Originalmente é constituída de carne bovina (corte traseiro), leite, cebolinha, pimenta bode, pimenta do reino, alho e sal refinado. Atualmente, encontramos no comércio diversos tipos de linguiça cuiabana, diferenciadas por condimentos, queijos, cortes musculares ou por espécies animais (suína, bovina, frango). No presente trabalho, juntamente com seu levantamento histórico, estudaram-se as características tecnológicas/ sensoriais da linguiça cuiabana. Foi realizado o processamento sob condições assépticas, de 4 formulações da linguiça tipo cuiabana, variando a principal matéria-prima utilizada (carne bovina, frango, suína). No processamento, as matérias-primas (bovina, frango e suína) foram cortadas em cubos que, juntamente com outros ingredientes (alho, queijo, pimenta e cebolinha), foram pesados e homogeneizados. A massa resultante foi deixada em repouso sob refrigeração por 24 horas para melhor desenvolvimento do sabor. Após descanso da massa, foi realizado o embutimento em tripas naturais. A partir destas amostras foram realizadas a caracterização do perfil físico-químico e avaliação sob refrigeração, ao longo de 7 dias de armazenamento por meio de análises microbiológicas (coliformes totais e termotolerantes (fecais), clostrídrios sulfito redutores, Salmonella spp., Staphylococcus coagulase positiva), pH, TBA. Por fim, a avaliação sensorial e estatística das diferentes linguiças tipo cuiabana processadas em laboratório. Os resultados mostraram que as variações ao longo do tempo na formulação das linguiças cuiabanas são fatores positivos, ficando evidente que as transformações são bem mais aceitas que a precursora, o que possivelmente ocorreram em função da demanda do mercado.
Abstract: The cuiabana sausage has wide acceptance in the municipality of Sao Jose do Rio Preto and surrounding regions. Originally, it consisted of beef (cut back), milk, chives, goat pepper, black pepper, garlic and salt. Currently, various types of cuiabana sausage are found in trade and they are distinguished by spices, cheeses, muscle cut or animal species (bovine, chicken and swine). In this paper, along with a historical survey, we studied the technical/ sensory characteristics of cuiabana sausage. Processing was performed under aseptic conditions for 4 formulations of sausage type cuiabana, varying the main raw material (bovine, chicken and swine). In processing, the raw meat (beef, chicken and pork) was cut into cubes, which together with other ingredients (garlic, cheese, pepper and chives), were weighed and homogenized. The resulting mass was subjected to refrigeration for 24 hours in order to develop better. After the dough we rested, the inlay was inserted in natural casings. These samples were used to characterize both the physical-chemical profile and also the evaluation under refrigeration, for over a 7 days-storage in order to assess microbiological contamination (total coliforms and thermotolerant (fecal), sulphite reducing clostrídrios, Salmonella spp. , Staphylococcus coagulase positive), pH, TBA. Finally, the sensory evaluation and statistics of the different types of cuiabana sausage processed in the laboratory were performed. The results showed that changes over time in the formulation of cuiabana sausages are positive factors, demonstrating, thus, that the changes are much more accepted than the precursor, which possibly occurred as a function of market demand.
Orientador: Pedro Fernando Romanelli
Coorientador: José Francisco Lopes Filho
Banca: Elizeu Antonio Rossi
Banca: Fernando Leite Hoffmann
Mestre

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29

Bairinhas, Marisa Alexandra Vitorino. "Polpas de maçã estabilizadas pela adição de aditivos. Impacto da componente bioactiva." Master's thesis, ISA, 2010. http://hdl.handle.net/10400.5/3083.

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Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de Agronomia
Ever since prehistoric times the man has been diversifying their diet and constantly improving the techniques of food preservation. Nowadays advances are such that the consumer can have a variety of foods, with appealing sensory properties, a high nutritional value and contribute fully preserved to their health and well-being. The act of eating is no longer considered a mere caloric intake needed to maintain the metabolic activity of our body, therefore an alliance as arisen between the intake of nutrients of common foods and the functional foods that besides being healthy are also a source of pleasure. Given this growing health concern and the cult of functional food increasingly sought by consumers, the horticultural industry has suffered a major expansion over recent years. The consumption increase of fruit and vegetables is due, among other things, to the greater availability and better preparation of products in the market and also to the greater awareness by consumers of the important relationship between diet and health. The political and economic scenario that results of globalization makes the development of new products a key factor for business competitiveness by imposing a very fast market dynamic. The modern consumer demands innovative products, with convenience and adequate quality. The objective of this dissertation is to create a product that becomes an answer to the needs of the consumers and the food industry, a Fuji apple pulp stabilized by additives, which will provide a greater nutritional value to the product and a longer shelf life. This pulp will be enriched with antioxidants and dietary fiber and will undergo a study on the effects of de incorporation of additives on the bioactive compounds of the product. For this study the pulps will be under freezing conditions (-18ºC) during 36 days. The experiment was developed in several phases, the first one being the base formulation of the product, its constituents, and based on the results it was decided that the formulation would consist of: 5% pineapple, 5% lemon, 3% blackberry and 2% wheat bran. Two pulps were produced, one with apple, pineapple, blackberry and wheat bran; the other with apple, lemon, blackberry and wheat bran. The stabilization of the pulps was achieved through the use of two food additives: ascorbic acid and citric acid; and completed with a freezing process. This represented a second phase of the experiment, the formulation of the additives concentration. Physical, chemical and sensory analyses were carried out in order to achieve the characterization of the product and the acceptance levels of additives. The parameters evaluated during this phase were: CIE Lab colour, the measurements of dry matter, ash content, pH, total soluble solids, mineral content, water activity, fiber content, total phenols, acidity and ascorbic acid content. All the samples were submitted to sensory analyses. The results were statistically treated using RSM methodology through the statistical program Statistica 8.0. The third phase consisted on the optimization of the pulps formulation. The products were submitted to the same kind of characterization plus the study of the role that the fiber incorporation had on the pulps. The final results showed that the addition of 0,6% ascorbic acid and 0,4% citric acid makes it possible to obtain a pulp with better sensory acceptance and also chemically stable. The phenolic and fiber component of the pulps is very high which indicates that this might be a product with functional properties beyond the nutritional value. The fiber incorporation study showed that it enhances the nutritional value of the pulp. The fourth and final phase was the study of the antioxidant capacity of the final product (pulp with Fuji apple, pineapple (5%), blackberry (3%), wheat bran (2%), ascorbic acid (0,6%) and citric acid (0,4%)), which demonstrated the difference between the final pulp, with all its ingredients and a pulp with only one or two chosen ingredients. This allowed to perceive that this experiment culminated with the development of a product chemically safe, with good quality parameters, and functional properties, rich in fiber, mainly hemicelluloses, a component that promotes the regulation of gastrointestinal transit since they are not digestible by the human body. This product is also rich in minerals such as magnesium and potassium, and antioxidants.

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Rocha, Maria Margareth Rolim Martins. "Liofilização como método de agregar valor ao camarão marinho litopenaeus vannamei." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/4092.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The marine shrimp Litopenaeus vannamei is a worldwide cultivated species, which is responsible for almost all the production of marine aquaculture in Brazil. Besides having a high nutritional value, it is also appreciated by consumers and there is the possibility of elaborating value-added products. The aim of this study is to evaluate the quality of the marine shrimp Litopenaeus vannamei in its lyophilizated form, using samples without pre-cooking and pre-cooked ones, and adding to them the tri and polyphospates and EDTA adictives. Experiences were made in order to determin the most adequate form of the shrimps rehydration and the physico-chemical analysis gathering centesimal composition, water activity, colour, water retention capacity, cholesterol level precision, fatty acids, aminoacids, vitamins, minerals, besides the caloric value, microbiological analysis and sensorial analysis. Lyophilization is a drying process in which the water passes from the solid to the vapor state, without going through the liquid state, leading to a decrease of the water activity and the food can be kept in room temperature. In this study, the rehydration was achieved in 2.5 minutes. The results showed that the Lyophilization process did not cause significant differences for water activity, pH and gain of weight in the rehydration. There has been a significantly different number for CRA in the TPF 5%-PC-L (99.99%). Lipids, proteins and ashes presented numbers with significant difference.The pré-cooked shrimps showed greater intensity of colour (62,05 to 71,06 for the angle a* and 19,22 to 32,59 for the angle b*). Phosphorus and Calcium presented figures between 189,06 and 301, 22 mg/100g. Cholesterol varied from 70,06 to 78,44 mg/100g. Fatty Acids with larger incidence were the mono and poliinsaturated. The aminoacids showed significant oscilations. The result of the sensorial analysis showed that the marine shrimp Litopenaeus vannamei lyophilizated is a product with a added value of great acceptation according to the consumers test.
O camarão marinho Litpenaeus vannamei é uma espécie cultivada em todo mundo, sendo responsável por quase toda produção da aquicultura marinha do Brasil. Além de ser um alimento de alto valor nutricional é bastante apreciado pelos consumidores podem ser elaborados produtos com valor agregado. Nesse contexto, de forma a avaliar a qualidade do camarão marinho, Litopenaeus vannamei, foram elaborados produtos sob a forma liofilizada utilizando-se amostras sem pre cozimento e pre cozidas, adicionadas dos aditivos tripolifosfato de sódio e EDTA. Foram realizados ensaios para a determinar a forma mais adequada da reidratação dos camarões e as análises físico-químicas envolvendo composição centesimal, atividade de água, cor, capacidade de retenção de água, determinação do teor de colesterol, ácidos graxos, aminoácidos, vitaminas, minerais, além do valor calórico, análises microbiológicas e analise sensorial. A liofilização, é um processo de secagem onde a água passa do estado sólido para o de vapor, sem passar pelo estado líquido, ocasionando uma redução da atividade de água e o alimento pode ser conservado em temperatura ambiente. No presente estudo a reidratação foi obtida em 2,5 minutos. Os resultados mostraram que o processo de liofilização não causou diferenças significativas para atividade de água, pH e ganho de peso na reidratação. Houve um valor significativamente diferente para CRA no TPF 5%-PC-L (99.99%). Lipídios, proteínas e cinzas apresentaram valores com diferença significativa. Os camarões pré cozidos apresentaram maior intensidade de cor (62,05 a 71,06 para o ângulo a* e 19,22 a 32,59 para o ângulo b*). Fósforo e Cálcio apresentaram valores entre 189,06 a 301, 22 mg/100g. Colesterol variou de 70,06 a 78,44 mg/100g. Os ácidos graxos com maior incidência foram os mono e poliinsaturados. Os aminoácidos apresentaram variações significativas. O resultado da análise sensorial mostrou que o camarão marinho Litopenaeus vannamei é um produto com valor agregado de grande aceitação pelo teste dos consumidores.

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Batista, Raquel de Almeida. "Produção e avaliação sensorial de cerveja com Pinhão (Araucaria angustifolia)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/97/97132/tde-24032015-160430/.

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Cerveja é toda bebida obtida pela fermentação alcoólica do mosto cervejeiro oriundo do malte de cevada e água potável, por ação da levedura, com adição de lúpulo, podendo ainda parte do malte de cevada ser substituído por cereais malteados ou não e por carboidratos de origem vegetal transformados ou não. Nota-se quenas duas últimas décadas tem ocorrido um fenômeno no universo cervejeiro, o crescimento do mercado de cervejas que empregam adjuntos, entre eles os mais comuns como milho e trigo, e os não convencionais, como banana, canela, arroz preto. Visando a adição de características sensoriais diferentes adquiridas por provadores mais exigentes, aliado à redução de custos pela diminuição do uso de malte de cevada, o pinhão surge como alternativa de adjunto para a produção de cerveja. Este adjunto além de possuir conteúdo apropriado de amido, possui uma casca com compostos fenólicos que podem conferir coloração diferenciada ao produto. O principal objetivo desta pesquisa foi produzir uma cerveja utilizando diferentes proporções de malte de cevada e de pinhão de forma a se obter uma bebida alcoólica diferenciada que atenda a expectativa do consumidor. Inicialmente, testes preliminares foram realizados para determinar se a proporção de malte em relação ao pinhão seria suficiente para sacarificar todos os açúcares durante as etapas da mosturação. Após isto formulou-se 6 cervejas com diferentes proporções de pinhão e malte (10:90, 45:55 e 80:20 com e sem casca), em escala de bancada, em Erlenmeyer com capacidade de 2L, contendo 1,2L de mosto a 10,9°P e aquelas duas mais aceitas no teste de aceitação (sensorial) (10% pinhão com casca e 45% pinhão sem casca) foram reproduzidas em escala piloto (em reator com capacidade para 120L, contendo 50L de mosto). Os resultados mostraram que as cervejas produzidas (em escala de bancada) com maior teor de pinhão e com casca obtiveram os menores resultados de teor alcoólico. Isto ocorreu devido à maior concentração de compostos fenólicos presentes na casca de pinhão que são menos assimiláveis pela levedura, tendo a cerveja com 10% pinhão sem casca (em escala de bancada) a que obteve os melhores resultados em conversão em etanol bem como o grau de atenuação aparente(0,61). O aumento da escala de produção de bancada para escala piloto resultou numa diminuição do valor de extratos e teor alcoólico, devido à uma necessidade de maior utilização de água de lavagem (diminuição teor extratos). Para a análise sensorial, as amostras que apresentaram diferença estatísticaem nível de 5% de probabilidade entre si pelo teste t de Student e que foram escolhidas para reprodução em escala piloto foram as de 10% de pinhão com casca e de 45% de pinhão sem casca. Para a escala piloto, a cerveja comercial foi mais aceita em relação às amostras contendo pinhão (tanto para 10% com casca como 45% sem casca), para todos os atributos avaliados (coloração, aroma, gosto, impressão global e intenção de compra). Ainda assim, as cervejas produzidas em escala piloto foram tão bem ou mais aceitas que as mesmas proporções produzidas em escala de bancada, em relação ao parâmetro impressão global.
Beer is all beverage obtained by alcoholic fermentation of brewery wort provided of barley malt and water, with addiction of hop, may also the barley malt used in the elaboration of beer and of hop were substituted by your respective extracts. Part of the barley malt can be substituted by malted cereals or not, and for carbohydrates of vegetal origin transformed or not. This possibilities that the last two decades a phenomenon in the brewery universe, the growth of the beer markets that uses adjuncts besides them the most common as corn and wheat, and the nonconventional, as banana, cinnamon, black rice. Aiming to an addiction of different sensorial characteristics acquired by tasters more exigent, and to the reduction of costs by de diminution of use of barley malt, the \"pinhão\" surges as alternative of adjunct for the beer production. This adjunct besides have an appropriate content of starch, have a barley with phenolic compounds that can contribute for a differentially color to the product. The main objective of this search was produce a beer using different proportions of barley malt and of \"pinhão\" in order to obtain a differentiate alcoholic beverage that attends the expectation of consumer. Initially, preliminary tests were performed to determine the proportion of malt with respect to the pinion would be sufficient to sacarifice all sugars during mashing steps. After this, it was formulated 6 different proportions of \"pinhão\" and malt (10:90, 45:55 e 80:20 with and without bark),in bench scale in Erlenmeyer flasks with capacity 2L, 1,2L of wort containing 10.9 ° P and those two are more acceptable in acceptance test (sensory) (10% \"pinhão\" with bark and 45% \"pinhão\" without bark) were reproduced in pilot scale (in reactor with a capacity of 120L, containing 50L of wort). The results showed that those with higher levels of \"pinhão\" with and without bark had the lowest alcohol content results, probably because of the higher concentration of phenolic compounds that are present in the \"pinhão\" bark that are less assimilable by yeast, having the beer with 10% \"pinhão\" (in stand scale) that obtained the best results in ethanol conversion. The best attenuation degree was when utilized the proportion 10% of \"pinhão\" with barley (0.60). The increase of scale of stand scale for pilot scale results in diminution of value of extracts and alcoholic content, due to an necessity of more utilization of washing water (diminution of content of extracts), having the beer with 10% of \"pinhão\" with barley obtained superiors results compared with 45% without bark, that was shown in stand scale. For the sensorial analysis, in relation to stand scale, the samples that presented statistical differences in level of 5% of probability by the t of Student and was chosen to make in pilot scale was 10% of pinhão with bark and 45% \"pinhão\" without bark.For the pilot scale, the commercial beer was more accepted in relation to the sample containing pinhão (for both cases, with 10% with bark and 45% without bark), for all evaluated attributes (color, aroma, flavor, global impression and intention of buy).However, comparing the stand with pilot scale, it has noticed an increase of the value of global evaluation during sensorial analysis. However, the beer produced in pilot scale was so or more accepted than the same proportions produced in bench scale, in relation to the parameter global impression.

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Machado, Andréa Rosa. "Aspectos físico-químicos de pernis suínos submetidos a tratamentos com ácidos orgânicos e vapor." Universidade do Estado de Santa Catarina, 2009. http://tede.udesc.br/handle/handle/824.

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The main objective of the slaughtering of animals for human consumption is to obtain meat in quantity and with quality. Thus, the meat needs to be within the standards required by current legislation. However, the agroindustry still faces serious problems due to microbiological contamination of carcasses during slaughter and/or processing. Alternatives proposed aiming to decontaminate carcasses during slaughter include treatment with the use of organic acids and/or steam. Such treatments aim to ensure the biological safety of foods and complement the autocontrol programs of industry on a prevention basis, such as hygiene care during the handling of foods and the sanitization of equipment to avoid any type of cross contamination. However, little research has provided conclusive information regarding whether these treatments lead to organoleptic and physico-chemical changes in the pork, which would be completely undesirable in terms of the quality parameters. Thus, this study aims to evaluate the possible physico-chemical changes in pork legs submitted to treatments with organics acids, steam and a combination of the two treatments. Visual and sensory analysis was carried out on the aspect, color, consistency and odor, before and after each treatment, together with physico-chemical analysis in order to determine the pH and the percentage of lipids, proteins, moisture and volatile compounds, also before and after each treatment. The results obtained revealed that the treatments used did not interfere in the attributes of aspect, color, odor and consistency and also did not lead to changes in the physico-chemical properties, with the exception that the treatment using organic acid combined with steam led to a decrease in the pH and increase in the moisture content and volatile compounds in the meat. However, this treatment did not denature the physicochemical quality of the pork, which remained within the standards, and therefore appropriate for human consumption
O abate de animais para o consumo humano tem por objetivo principal a obtenção de carne em quantidade e em qualidade. Para isso, é necessário que a carne esteja dentro dos padrões exigidos pela legislação vigente, porém, as agroindústrias ainda enfrentam sérios problemas com relação à contaminação microbiológica de carcaças durante o abate e/ou processamento. Entre as alternativas propostas visando descontaminar carcaças no abate, tem sido proposto o tratamento com uso de ácidos orgânicos e/ou vapor. Tais tratamentos têm o objetivo de garantir a segurança biológica dos alimentos e complementar os programas de autocontrole das indústrias de caráter preventivo, como os cuidados higiênicos na manipulação dos alimentos e na higienização dos equipamentos evitando todo e qualquer tipo de contaminação cruzada. Porém, poucas pesquisas trazem informações conclusivas sobre o fato desses tratamentos promoverem ou não alterações físico-químicas da carne suína, o que seria totalmente indesejável frente a seus parâmetros de qualidade. Assim sendo, o presente projeto se propôs a avaliar as possíveis alterações físico-químicas de pernis suínos submetidos a tratamentos com ácidos orgânicos, vapor e associação dos dois tratamentos. Sendo realizadas análises visuais e sensoriais de aspecto, coloração, consistência e odor, antes e após cada tratamento, bem como, análises físico-químicas visando determinação do percentual de lipídeos, proteínas, pH, umidade e voláteis, também, antes e após cada tratamento. Os resultados obtidos revelaram que os tratamentos utilizados não interferiram nos atributos aspecto, cor, odor e consistência e, também, não alteraram suas propriedades físico-químicas, sendo que, somente o tratamento de vapor associado aos ácidos orgânicos diminuiu o pH e aumentou o teor de umidade e voláteis da carne, porém, não descaracterizou a qualidade físico-química da carne suína, que permaneceu dentro de seus padrões ideais, apta ao consumo humano

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Pereira, Luzimario Lima. "Análise físico-química de amostras de méis de Apis mellifera e Meliponíneos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-29112010-082905/.

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O mel de abelhas é um produto biológico muito complexo, cuja composição varia notavelmente em função da flora visitada pelas abelhas e das condições climáticas e edáficas da região onde foi produzido. Este trabalho teve como objetivos confrontar os resultados das análises físico-químicas entre as amostras de méis produzidos em diferentes localidades do Brasil por Apis mellifera e por Meliponíneos e investigar se o mel produzido por essas abelhas nas suas diferentes regiões de origem apresenta níveis toleráveis de contaminantes inorgânicos. Para tanto, foram avaliadas 56 amostras de méis de A. mellifera e 56 amostras de méis de Meliponíneos dos Estados da Bahia, Minas Gerais, Mato Grosso do Sul, Paraíba, Piauí, Paraná, Santa Catarina e São Paulo, em relação aos seguintes parâmetros: umidade, atividade de água, viscosidade, pH, acidez livre, índice de formol, açúcares redutores, sacarose aparente, teor de cinzas, cor, condutividade elétrica, hidroximetilfurfural, atividade diastásica e metais (Hg+2, Zn+2, Cd+2, Pb+2 e Cu+2). Foi utilizada a técnica de Voltametria de Redissolução Anódica de Pulso Diferencial (DPASV) para quantificar os metais, e métodos convencionais e próprios para mel nas demais análises. Os resultados mostraram que a legislação atual, referente ao mel de A. mellifera, não é adequada para os parâmetros açúcares redutores, umidade e atividade diastásica de algumas espécies de Meliponíneos. Pôdese concluir que as espécies A. mellifera, Tetragonisca angustula, Melipona quadrifasciata, M. scutellaris, M. mandacaia, M. fasciculata, M. subnitida produzem méis com características físico-químicas diferentes e próprias de cada uma delas. Para todas as espécies avaliadas, os níveis de contaminantes inorgânicos encontrados nos méis foram toleráveis à saúde humana. Os méis produzidos por A. mellifera apresentaram variações nas características físico-químicas: atividade de água, viscosidade, acidez livre, índice de formol, açúcares redutores, condutividade elétrica, hidroximetilfurfural, atividade diastásica e o mineral zinco, em função dos diferentes locais onde foram produzidos.
The honeybee is a very complex biological product, whose composition varies markedly depending on the plant visited by the bees and the weather and soil conditions in the region where it was produced. This study aimed to compare the results of physicochemical analysis between the samples of honey produced in different locations in Brazil by Apis mellifera and Meliponid and to investigate whether honey produced by these bees, in different regions of origin, has tolerable levels of inorganic contaminants. To this end, we evaluated 56 samples of honey from A. mellifera and 56 samples of honey from Meliponid from the states of Bahia, Minas Gerais, Mato Grosso do Sul, Paraíba, Piauí, Paraná, Santa Catarina and São Paulo, for the following parameters: moisture content, water activity, viscosity, pH, free acidity, formol index, reducing sugars, apparent sucrose, ash content, color, electrical conductivity, hydroxymethylfurfural, diastase activity and metals (Hg+2, Zn+2, Cd+2, Pb+2 and Cu+2). Differential Pulse Anodic Stripping Voltammetry (DPASV) technique was used to quantify the metals, and, to the other analysis, conventional and suitable methods for honey were used. The results showed that the current legislation, referring to the honey of A. mellifera, is not appropriate for the parameters reducing sugars, moisture content and diastase activity of some species of Meliponid. It was concluded that the species A. mellifera, Tetragonisca angustula, Melipona quadrifasciata, M. scutellaris, M. mandacaia, M. fasciculata, M. subnitida produce honeys with different and specific physico-chemical characteristics. For all species studied, levels of inorganic contaminants found in honey were tolerable to human health. The honey produced by A. mellifera showed variations in physicochemical water activity, viscosity, free acidity, formol index, reducing sugars, electrical conductivity, hydroxymethylfurfural, diastase activity and the mineral zinc, depending on the different locations where they were produced.

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Zanão, Cíntia Fernanda Pedroso. "Características físico-químicas e sensoriais do arroz (Oryza sativa L.) irradiado e o efeito no desenvolvimento de Sitophilus oryzae L." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11141/tde-14092007-135438/.

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O arroz sofre danos principalmente pelo ataque de insetos, causando grandes perdas qualitativas e quantitativas, devido a isso, a presente pesquisa teve como objetivo verificar a viabilidade da radiação gama como método de conservação do arroz (Oryza sativa L.), sua eficiência no controle de uma importante praga de grão armazenado Sitophilus oryzae L. e os efeitos que a irradiação pode apresentar nos grãos irradiados considerando o aspecto sensorial e alteração no amido. As amostras foram constituídas de arroz polido e as doses de radiação gama utilizadas foram 0,5; 1,0; 3,0; e 5,0 kGy, sendo mantidas em temperatura ambiente. Foram realizadas análises da porcentagem de quebra do grão durante o beneficiamento e análise da longevidade e reprodução do gorgulho arroz. Foram realizadas também, as análises da composição centesimal, ácido fítico, conteúdo de amilose aparente e propriedades de pasta dos amidos além das análises para cor (instrumental) em arroz e a aceitabilidade (teste hedônico) visando à determinação da qualidade sensorial do arroz cru e cozido. Verificou-se que a irradiação não alterou de maneira significativa à quebra dos grãos durante o beneficiamento e causou efeito negativo no desenvolvimento dos insetos. A irradiação não alterou de maneira significativa à composição centesimal. Não foi encontrado valor significativo de ácido fítico, devido ao arroz ter sofrido o beneficiamento, retirando a parte externa (farelo) onde contém 85 – 92% de fitatos totais. Foram encontrados valores de 17,33 a 18,44% para conteúdo de amilose aparente, sendo que a irradiação não afetou significativamente a conteúdo de amilose do amido do arroz. Os resultados da propriedade de pasta foram significativamente alterados, ocorrendo à redução da temperatura de pasta, diminuição do tempo para ocorrência do pico viscosidade, redução nos valores de viscosidade máxima e viscosidade final e a tendência de retrogradação se tornou menos acentuada nos amidos com doses crescente de radiação gama. Foram detectadas diferenças estatísticas (p<0,05) no aspecto sensorial entre as amostras irradiadas e não irradiadas, sendo que a amostra irradiada com a dose de 1,0 kGy obteve maiores médias para os atributos sensoriais. Para os resultados encontrados na cor instrumental observou a diferença estatística nos valores b* indicando que o arroz sofreu mudanças de branco para amarelada com o aumento da dose de radiação gama. Conclui-se que o uso da radiação gama, especialmente a dose de 1,0 kGy, mesmo apresentando diferença significativa (p< 0,05) nas propriedades de pasta, proporcionou maior aceitação pelos provadores, não afetou as análises físico-químicas, assegurando maior vida-útil contra o ataque de insetos, desde que não haja reinfestação, sendo portanto a dose recomendável para a conservação do arroz polido.
Rice is exposed to injuries especially due to the attack of insects, which represent great qualitative and quantitative losses. The aim of the present research was to verify the viability of the gamma irradiation as rice (Oryza sativa L.) conservation method; its efficiency in the control of an important pest for stored grains Sitophilus oryzae L. and the effects that irradiation may present in irradiated grains in relation to the sensory aspect and starch alterations. Samples were composed of polished rice and the gamma irradiation dosages used were 0.5; 1.0; 3.0; and 5.0 kGy, and kept at room temperature. Analyses of the grain breakage percentages during processing and the longevity and reproduction of the rice weevil were performed. Analyses of the centesimal composition, phytic acid, apparent amylose content and starch paste properties were also conducted, as well as analyses of the rice color (instrumental) and acceptability (hedonic test), aimed at the determination of the raw and cooked rice sensory quality. It was verified that the gamma irradiation did not change the grain breakage percentage significantly and caused a negative effect on the insect development. Irradiation did not change the centesimal composition significantly. No significant values of phytic acid were found because during rice processing, the outer part (bran) containing 85-92% of total phytates was removed. Values from 17.33 to 18.44% for the apparent amylose content were found, and irradiation did not affect the rice starch amylose content significantly. The paste properties results were significantly changed, where reduction on the paste temperature, decrease on the time for the occurrence of the peak viscosity, reduction on the final viscosity values were observed. The retrogradation tendency became less intense in starches with increasing irradiation dosages. Statistical differences (p<0.05) were detected in the sensory aspect between irradiated and non-irradiated samples, and the sample irradiated with 1.0 kGy obtained the highest means for the sensory attributes. For results obtained for instrumental color, a statistical difference was observed in b* values, indicating that the rice color changed from white to yellowish with increased irradiation dosages. One concluded that the use of the gamma irradiation especially at dosage of 1.0 kGy, even presenting significant difference (p<0.05) in the paste properties, obtained higher acceptance; this irradiation level did not affect the rice physical-chemical analyses and provided longer shelf-life against the attack of insects, being therefore, the recommended dosage for the conservation of the polished rice.

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Silva, Marcus Vinícius Ivo da. "Efeitos do uso do biodiesel sobre propriedades do óleo lubrificante usado em um motor de ignição por compressão." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-02102006-153234/.

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Dentro da seqüência natural de testes para validar o uso do biodiesel (éster etílico) misturado ao óleo diesel em maiores proporções no Brasil, este trabalho teve o objetivo de estudar os efeitos do uso de uma mistura combustível B10 (com concentração de 10% em volume de biodiesel diluído em óleo diesel) na degradação do óleo lubrificante de um motor de ignição por compressão, aspirado, de 1,9 L e de injeção indireta. Acoplado a um dinamômetro, o motor foi submetido à condição de velocidade constante de 2.500 rpm, sob carga variável, e abastecido com três combustíveis diferentes: óleo diesel puro, B10 de biodiesel de soja e B10 de biodiesel de soja e nabo forrageiro. Cada combustível alimentou o motor durante 30 horas. Para determinar a degradação resultante, selecionaram-se as propriedades do óleo lubrificante usado em cada etapa para serem analisadas (viscosidade, contaminação por água e presença de elementos). Os resultados revelaram que o uso de 10% volume dos dois tipos de biodiesel na mistura combustível não causou variação significante na concentração de elementos e nas propriedades físico-químicas do óleo lubrificante.
Adding to an ongoing sequence of tests aimed at validating the use of biodiesel (ethyl ester) mixed with diesel in higher proportions in Brazil, this study was conducted to investigate the effects of utilizing a B10 fuel mixture (10% volume biodiesel diluted in diesel) on the degradation of lubricating oil in an aspirated, indirect-injection, 1.9 L compression-ignition engine. Coupled to a dynamometer, the engine was operated at a constant speed of 2,500 rpm under variable load and run with three types of fuel: pure diesel, B10 soy biodiesel, and B10 soy and fodder turnip biodiesel. Each type of fuel fed the engine for 30 hours. To determine the resulting degradation, selected properties of the lubricating oil used in each run were analyzed (viscosity, contamination by water and presence of elements). The results revealed that the use of a 10% volume of either type of biodiesel in the fuel mixture did not lead to significant variation in the concentration of elements or in the physico-chemical properties of the lubricating oil.

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Freitas, Patricia Antonio de Menezes. "Adsorção de Di-2-piridil cetona saliciloilhidrazona (DPKSH) em sílica-gel." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-08022018-085703/.

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Di-2-piridil cetona saliciloilhidrazona (DPKSH) é uma hidrazona que forma compostos de coordenação com diversos íons metálicos. DPKSH adsorve facilmente em superficies de vidro e pode ser determinado por espectrofotometria. Estudos de adsorção do DPKSH em matrizes de sílica-gel foram efetuados em pHap 1 e 4,7 e meio 3% de etanol (v/v), a (25±1) °C. Massas conhecidas de sílica-gel foram colocadas em contato com soluções de DPKSH em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A concentração de DPKSH adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração residual na solução sobrenadante, ambas obtidas a partir de medidas de absorbância. Estudo cinético permitiu encontrar o tempo adequado de contato sílica/DPKSH para adsorção máxima. Diferentes modelos de isotermas foram aplicados aos dados experimentais. Titulações condutométricas permitiram caracterizar as propriedades ácidas/básicas da sílica e da sílica modificada. Fez-se também um estudo preliminar sobre a retenção de íons Cu(II) na superficie de sílica-gel modificada com DPKSH.
Di-2-pyridyl ketone salicyloy1hydrazone (DPKSH) is a hydrazone that gives sensitive reactions with most of metal ions forming coulored chelates. DPKSH solutions present a visible adsorption onto glass when stored in glass bottles and can be determined by spectrophotometry. The adsorption of DPKSH onto silica gel has been investigated, at (25±l) °C and pHap 1 and 4.7 at aqueous solution containing 3%(v/v) ethanol. Masses well-known of silica gel were placed in contact with known concentration DPKSH solutions, under agitation during certain intervals of time. The quantity of DPKSH adsorbed was calculated considering the difference between the initial DPKSH concentration and the residual one in the sobrenadant solution after achieved the equilibrium, both obtained from absorbance measurements. Kinetic studies allowed to find the optimal rime for the contact silica DPKSH in order to obtain the maximum adsorption. Different models of isotherms were applied to the experimental data. Condutometric titrations led to acid/basic characteristics of silica and modified silica. A preliminary study of Cu(II) ions retention into silica gel surface modified with DPKSH was carried out.

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37

Camborata, Cecilia <1987&gt. "Semi-synthetic bile acids as novel drug candidate in liver diseases: physico-chemical characterization and HPLC-ES-MS/MS methods for their quali-quantitative analysis in different experimental animal models." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6823/.

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The physico-chemical characterization, structure-pharmacokinetic and metabolism studies of new semi synthetic analogues of natural bile acids (BAs) drug candidates have been performed. Recent studies discovered a role of BAs as agonists of FXR and TGR5 receptor, thus opening new therapeutic target for the treatment of liver diseases or metabolic disorders. Up to twenty new semisynthetic analogues have been synthesized and studied in order to find promising novel drugs candidates. In order to define the BAs structure-activity relationship, their main physico-chemical properties (solubility, detergency, lipophilicity and affinity with serum albumin) have been measured with validated analytical methodologies. Their metabolism and biodistribution has been studied in “bile fistula rat”, model where each BA is acutely administered through duodenal and femoral infusion and bile collected at different time interval allowing to define the relationship between structure and intestinal absorption and hepatic uptake ,metabolism and systemic spill-over. One of the studied analogues, 6α-ethyl-3α7α-dihydroxy-5β-cholanic acid, analogue of CDCA (INT 747, Obeticholic Acid (OCA)), recently under approval for the treatment of cholestatic liver diseases, requires additional studies to ensure its safety and lack of toxicity when administered to patients with a strong liver impairment. For this purpose, CCl4 inhalation to rat causing hepatic decompensation (cirrhosis) animal model has been developed and used to define the difference of OCA biodistribution in respect to control animals trying to define whether peripheral tissues might be also exposed as a result of toxic plasma levels of OCA, evaluating also the endogenous BAs biodistribution. An accurate and sensitive HPLC-ES-MS/MS method is developed to identify and quantify all BAs in biological matrices (bile, plasma, urine, liver, kidney, intestinal content and tissue) for which a sample pretreatment have been optimized.

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38

Fernandes, Andrezza Maria. "Efeitos dos níveis de células somáticas sobre a qualidade do leite integral obtido por processo UAT direto." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-17052007-093011/.

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O objetivo do estudo foi avaliar os efeitos da contagem de células somáticas (CCS) sobre características físico-químicas (pH, acidez, composição, cor), microbiológicas, índices de proteólise e lipólise, formação de compostos de Maillard, viscosidade aparente e frações protéicas do leite integral obtido pelo processamento direto de temperatura ultra alta (UAT). O leite cru foi avaliado quanto ao nível de células somáticas (CS) e características físicoquímicas. As amostras de leite foram colhidas em usina de beneficiamento de leite UAT no Estado de São Paulo. O leite cru foi submetido à pasteurização rápida e foi efetuada a esterilização industrial do leite por processo UAT direto, seguido do envase do produto. As análises no leite UAT foram realizadas nos dias 8, 30, 60, 90 e 120 após a fabricação. Quinze lotes de leite UAT foram avaliados para verificar a correlação entre a CCS e as variáveis estudadas. Adicionalmente, os lotes foram categorizados em grupos de baixa, intermediária e alta CCS. No leite cru, houve correlação negativa (r= -0,54, P=0,04) entre CCS e níveis de αS2 e ß-caseína. No leite UAT, o aumento da CCS foi acompanhado de uma diminuição dos níveis de αs1-caseína (r= -0,56, P=0,03) e ß-caseína (r= -0,56, P=0,03) aos 8 dias de armazenamento. No 60º dia após a fabricação a CCS foi correlacionada à diminuição de αS2-caseína (r= -0,69, P=0,005). A CCS exerceu efeito significativo (P=0,02) sobre o componente a*, com maiores (P=0,02) valores para o grupo de alta CCS em relação ao de CCS intermediária, e sobre a ß-caseína (P=0,02), com menores (P=0,03) concentrações no grupo de alta CCS comparado ao de CCS baixa. Os valores de pH, L*, proteína verdadeira e caseína apresentaram diminuição significativa ao longo do armazenamento. Contrariamente, a acidez, o componente a*, os ácidos graxos livres, a viscosidade e a proteólise aumentaram significativamente. A quantidade de caseína em relação à proteína verdadeira foi negativamente correlacionada à CCS no 120º dia de armazenamento. Observou-se redução significativa nas concentrações de frações protéicas durante o armazenamento, com exceção da αS2-caseína. A CCS no leite cru utilizado para a fabricação de leite UAT pode prejudicar a qualidade do produto por possíveis alterações decorrentes da proteólise no final da vida de prateleira.
The aim of this study was to evaluate the effects of somatic cell counts (SCC) on physicochemical characteristics (pH, acidity, composition, color), microbiology, proteolysis and lipolysis indexes, Maillard compound formation, apparent viscosity and protein fractions of whole milk obtained by direct ultra high temperature (UHT) process. The raw milk was analyzed for somatic cell (SC) levels and physico-chemical characteristics. Milk samples were collected in a dairy plant in São Paulo State. Raw milk was submitted to HT-ST pasteurization and industrial sterilization was taken by direct UHT process, followed by the packing. UHT milk analyses were conducted on days 8, 30, 60, 90 and 120 of storage. Fifteen batches of UHT milk were evaluated for correlations between SCC and the parameters studied. Additionally, UHT milks were categorized in selected groups of low, intermediate and high SCC. Raw milk presented a negative correlation (r= -0.54, P=0.04) between CSS and levels of αS2 and ß-casein. In UHT milk, SCC increase was followed by a reduction of αS1-casein (r= -0.56, P=0.03) and ß-casein (r= -0.56, P=0.03) concentrations on the 8th day of storage. On 60th day of storage, SCC was correlated with the reduction (r= -0.69, P=0.005) on αS2-casein concentration. SCC had significant effect on component a* (P=0.02), which values were higher (P=0.02) on high SCC group compared to the intermediate SCC group, and on ß-casein (P=0.02), with lower (P=0.03) concentrations in high SCC group than in low SCC group. Values of pH, L*, true protein and casein presented significant reduction during storage. Conversely, acidity, component a*, free fatty acids, viscosity and proteolysis increased significantly. Casein in relation to true protein was negatively correlated with SCC on 120th day of storage. It was observed a significant reduction on protein fractions concentrations in UHT milk during storage, except for αS2-casein. SCC in raw milk used for UHT milk production may prejudice the quality of the product through alterations caused by proteolysis in the end of shelf life.

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39

Loodts, Vanessa. "Influence of chemical reactions on convective dissolution: a theoretical study." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/242093.

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Studying the coupling between buoyancy-driven instabilities and chemical reactions is not only relevant to fundamental research, but has also recently gained increased interest because of its relevance to CO$_2$ sequestration in subsurface geological zones. This technique aims to limit the emissions of CO$_2$ to the atmosphere, with a view to mitigating climate change. When injected in e.g. a saline aquifer, CO$_2$ dissolves into the brine occupying the geological formation, thereby increasing the density of the aqueous phase. This increase of density upon dissolution leads to a denser fluid boundary layer rich in CO$_2$ on top of less dense fluid in the gravity field, which drives dissolution-driven convection. This process, also called convective dissolution, accelerates the transport of dissolved CO$_2$ to the host phase and thus improves the safety of CO$_2$ sequestration. The same kind of instability can develop in other contexts involving the dissolution of a phase A into a host phase, such as solid dissolution or transfer between partially miscible liquids. In this context, the goal of our thesis is to understand how chemical reactions coupled to dissolution-driven convection affect the dynamics of the dissolving species A in the host solution. To do so, we introduce a general reaction of the type A + B $rightarrow$ C where A, B and C affect the density of the aqueous solution. We theoretically analyze the influence of the relative physical properties of A, B and C on the convective dynamics. Our theoretical analysis uses a reaction-diffusion-convection model for the evolution of solute concentration in a host fluid solvent occupying a porous medium. First, we quantify the characteristic growth rate of the perturbations by using a linear stability analysis. Thereby we show that a chemical reaction can either accelerate or slow down the development of convection, depending on how it modifies the density profile that develops in the reactive solution. In addition, new dynamics are made possible by differential diffusion effects. Then, by analyzing the full nonlinear dynamics with the help of direct numerical simulations, we calculate the dissolution flux into the host phase. In particular, the dissolution flux can be amplified when convection develops earlier, as CO$_2$ is then transported faster away from the interface. Finally, we compare these theoretical and numerical predictions with results of laboratory experiments and discuss the possible implications of this study for CO$_2$ sequestration.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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40

Nazarova, Cherriere Marfa. "Wettability study through x-ray micro-ct pore space imaging in eor applied to lsb recovery process." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3030/document.

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La thèse a pour but d’étudier les effets de changements de mouillabilité de roches dans des conditions d’injections d’eau douce en tant que méthode de récupération d’hydrocarbures. Afin d’identifier le ou les mécanismes à l’origine du gain additionnel de récupération nous avons utilisé un microtomographe RX. Nous avons ainsi imagé les états de saturations finales d’un milieu poreux rempli de saumures et d’huiles. Une fois le drainage primaire réalisé nous avons effectué deux phases d’imbibitions : avec une saumure (récupération secondaire) puis une imbibition d’eau douce (récupération tertiaire). L’analyse de la mouillabilité à l’échelle du pore a permis de mettre en évidence l’effet de la température et de la salinité sur la mouillabilité. Nous avons montré que les changements de mouillages des roches n’étaient pas occasionnées par la seule expansion de la couche électrique en revanche des changements de mouillabilité ont été montrés. Ces changements s’expliquant par des transitions de mouillages de second ordre observées non seulement pour des gouttes d’huiles sur de l’eau mais également sur un substrat en verre. Au final, la mouillabilité en milieux poreux doit être mise en évidence à une échelle sous-Micrométrique ce qui est relativement nouveau dans le domaine pétrolier
The aim of the thesis is to study rock wettability change effects caused by Low Salinity brine injection as tertiary recovery method. To identify the underlying mechanism or mechanisms of additional oil recovery X-Ray imaging technology was applied. We have also imaged the end-Point saturations of filled by brine and water core samples. Once the primary drainage is realized we carried out two phases imbibitions: with high salinity brine (waterflooding) and with low salinity brine (tertiary recovery mode). The wettability analysis at pore scale permitted to put in evidence the thermal and saline effects playing a decisive role in rock wettability. We have showed wettability changes are not caused by only electrical double layer expansion, however wettability changes was shown. These changes are explained by wettability transition of second order and observed not only for oil droplet on brine, but also for oil deposited on glass substrate. Finally, the pore space wettability needs to be evidenced at sub-Micrometric scale that is new for the petroleum domain

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41

Vecchi, Giulia. "Proteomics studies of protein homeostasis and aggregation in ageing and neurodegeneration." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273348.

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Upon ageing, a progressive disruption of protein homeostasis often leads to extensive protein aggregation and neurodegeneration. It is therefore important to study at the proteome level the origins and consequences of such disruption, which so far have remained elusive. Addressing this problem has recently become possible by major advances in mass spectrometry-based (MS) proteomics, which allows the identifications and quantification of thousands of proteins in a variety of biological samples. In the first part of this thesis, I analyse proteome-wide MS data for the nematode worm C. elegans upon ageing, in wild type (WT), long-lived and short-lived mutant strains. By comparing the total abundance and the soluble abundance for nearly 4000 proteins, I provide extensive evidence that proteins are expressed in adult worms at levels close to their solubility limits. With the use of sequence-based prediction tools, I then identify specific physico-chemical properties associated with this age-related protein homeostasis impairment. The results that I obtained reveal that the total intracellular protein content remains constant, in spite of the fact that the proteome undergoes wide remodeling upon ageing, resulting into severe protein homeostasis disruption and widespread protein aggregation. These results suggest a protein-dependent decrease in solubility associated with the protein homeostasis failure. In the second part of the thesis, I determine and classify potential interactions of misfolded protein oligomers with other proteins. This phenomenon is widely believed to give rise to cytotoxicity, although the mechanisms by which this happens are not fully understood. To address this question, I process and analyse MS data from structurally different oligomers (toxic type A and nontoxic type B) of the protein HypF-N, incubated in vitro with proteins extracted from murine cell cultures. I find that more than 2500 proteins are pulled down with the misfolded oligomers. These results indicate that the two types of oligomers interact with the same pool of proteins and differ only in the degree of binding. Functional annotation analysis on the groups reveals a preference of the oligomers to bind proteins in specific biological pathways and categories, including in particular mitochondrial membrane proteins, RNA-binding proteins and molecular chaperones. Overall, in this study I complement the powerful and high-throughput experimental approach of MS proteomics with bioinformatics analyses and prediction algorithms to define the physical, chemical and biological features of protein homeostasis disruption upon ageing and the interactome of misfolded oligomers.

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42

Cano, Cristiane Bonaldi. "Caracterização dos méis monoflorais de eucalipto e laranja do Estado de São Paulo pela análise polínica e físico-química." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-18052015-120358/.

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A caracterização dos méis monoflorais tomou-se uma tendência mundial. Sendo assim, este trabalho apresenta o desenvolvimento e otimização de metodologias para as análises de carboidratos por Cromatografia Líquida de Alta Eficiência (CLAE), para o tipo de montagem da lâmina para a realização do espectro polínico e para a determinação do conteúdo de umidade, com o intuito de caracterizar as amostras de méis monoflorais de eucalipto e laranja de algumas regiões do Estado de São Paulo. Na análise polínica foi empregado o método modificado de Iwama e Melhem (1979) para limpeza dos grãos de pólen, e para a montagem da lâmina foi realizado um estudo de comparação entre o método de Iwama e Melhem (1979) e o método proposto (Louveaux modificado, 1978), através de um teste de duas proporções. No conteúdo de umidade foi realizada a comparação de dois métodos oficiais (AOAC e EHC) através de um planejamento fatorial e um estudo da variabilidade empregando-se um planejamento hierárquico. Para a análise do conteúdo de carboidratos realizou-se a otimização das condições de análise por CLAE, empregando-se um planejamento de misturas e uma análise de regressão linear para curvas de calibração, um teste-t para estudo da recuperação e uma análise de variância (ANOVA) para comparar os conteúdos de carboidratos das duas floradas. Na análise polínica pode se observar que o método proposto (Louveaux modificado) era o mais adequado visto que este apresentava uma maior distribuição das famílias de menor freqüência. Com os espectro polínicos (pólen dominante) das amostras de méis coletadas pode-se classificar os méis como monoflorais de eucalipto e laranja. Através da análise do espectro polínico completo pode-se observar que os méis monoflorais de laranja possuem uma diversificação maior de famílias em relação aos méis monoflorais de eucalipto, sugerindo que estes méis possuem uma maior variação de néctares e grãos de pólen na sua formação, sendo que este fato pode estar relacionado às regiões de cultivo. O planejamento fatorial 22 no conteúdo de umidade sugeriu que as amostras cristalizadas interferem na medida do índice de refração. O emprego do pré-tratamento da amostra (EHC) permitiu uma diminuição nos conteúdos de umidade das amostras cristalizadas. Quando este pré-tratamento foi usado para amostras líquidas não se observaram diferenças significativas no teor de umidade. Pode-se então sugerir que o método refratométrico da Comunidade Européia de Mel (EHC) seria os mais adequados para ser usada nas amostras líquidas e cristalizada. O estudo da variabilidade dos conteúdos de umidade realizado através de um planejamento hierárquico e análise de variância (ANOVA) indicaram que existem diferenças significativas entre as fontes florais e entre as amostras de méis. Foram escolhidas como melhores condições experimentais para a determinação dos carboidratos no mel por CLAE, o uso de coluna de aminopropil de tamanho menor (15,0cm x 4,5cm), e uma temperatura de 32°C na coluna e de 35,5°C para o detector de índice de refração e uma vazão de fluxo de 1,2 mL/min. Para a fase móvel o planejamento em misturas realizado, indicou como melhor fase móvel a mistura 50:10:40(acetonitrila; água; acetato de etila). Ao realizar as curvas de calibração dos carboidratos (glicose, frutose, sacarose, turanose e maltose) pode-se observar que estas eram lineares, com R2ajust altos e precisão aceitáveis para a quantificação dos carboidratos. Foi determinada a capacidade de detecção (0,2 - 0,4%) e capacidade de quantificação (0,7 - 1,3%) para a sacarose, turanose e maltose. O estudo de recuperação média dos carboidratos sugeriu que curvas de calibração poderiam ser utilizadas com confiança para determinar os conteúdos de carboidratos. A avaliação entre as concentrações médias dos carboidratos individuais pela ANOVA e pelo teste-t ao nível de 95% de confiança dos méis monoflorais de eucalipto e laranja, sugeriu que existem diferenças significativas nas concentrações de glicose, sacarose e turanose nas amostras de méis. Desta forma pode-se classificar os méis monoflorais de eucalipto e laranja através do espectro polínico. Conclui-se que as determinações do conteúdo de umidade e carboidratos (glicose, sacarose e turanose) podem se empregados para caracterizar a origem botânica dos méis monoflorais de eucalipto e laranja.
Considering the characterization of monofloral honeys as a worldwide tendency, this study presents the development and optimization of methodologies for carbohydrate analysis by HPLC, the kind of standardization for lamina preparations for pollen analysis and the determination of moisture content in order to characterize eucalyptus and orange monofloral honey samples from some regions in São Paulo State. The modified method of Iwama and Melhem (1979) was employed for pollen analysis pollen cleaning. For lamina preparation it a comparison study was made between the Iwana and Melhem (1979) method and the proposed method (Louveaux modified) through two proportion tests. A comparison for moisture content was made between two official methods (AOAC and EHC) through a factorial desing and a study of variability through hierarchical desings. For the carbohydrate content analysis an optimization of analysis conditions for HPLC was made using mixture desing and a linear regression analysis for calibration curves, a t-test for a recovery study and a variance analysis (ANOVA) to compare the carbohydrate contents of both floral origins. In pollen analysis one can observe that the proposed Louveaux modified method was the most adequate since it showed a bigger distribution of less frequently occcoring families. With the pollen spectrum (dominant pollen) from honey samples, the monoflorals of eucalyptus and orange, can be classified. And by complete pollen spectrum analysis one can observe that orange monofloral honeys contain more diversified families relative to eucalyptus monofloral honeys, suggesting these honeys have a bigger variation of nectars and pollen grains in their formation. This fact can be related to regions of plantation. The factorial desing 22 in moisture content suggests that the crystallized samples interfere in refractive index measurements. The (EHC) sample pre-treatment led to lower moisture contents of crystallized samples. When this pre-treatment was used for liquid samples no significant differences were observed concerning moisture content. Therefore it can be suggested that the EHC refractrometric method is more appropriate to use for liquid and crystallized samples. The study of moisture content variability through hierarchical desing and variance analysis indicates significant differences among floral sources and moisture content of honey samples. The use of a aminopropil column of smaller size (15,0 cm x 4,5 cm) and a temperature of 32 ° C in the column and 35,5 ° C for the refractive index detector and a flow rate of 1.2 ml/min were the best experimental conditions chosen to determine the carbohydrates in honey by HPLC. For the mobile phase the mixture desing indicated that the best combination was 50: 10: 40( acetonitrile, water, ethyl acetate). The calibration curves of the carbohydrates (glucose, fructose, sucrose, turanose, maltose) were linear, with high R2 and had acceptable accuracy for carbohydrate quantification. 80th the detection capacity and quantification capacities were determined the former being (0.2 - 0.4%) and the latter (0.7 - 1.3 %) for sucrose, turanose and maltose. The mean recovery study of carbohydrates suggested that the calibration curves are reliable to determine carbohydrate contents. The evaluation among the mean concentrations of individual carbohydrates by ANOVA and t-test at the 95% confidence level of eucalyptus and orange monofloral honeys suggested that there are significant differences in glucose, sucrose and turanose concentration in these honey samples. In this way eucalyptus and orange monofloral honeys can be classified by the pollen spectrum. Therefore, it was concluded that the eucalyptus and orange monofloral honeys can be classified by moisture content determination and/or carbohydrate (glucose, sucrose and turanose) determination.

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Badía, Valiente José David. "Strategies and analytical procedures for a sustainable plastic waste management. An application to poly (ethylene terephthalate) and polylactide in the packaging sector." Doctoral thesis, Editorial Universitat Politècnica de València, 2011. http://hdl.handle.net/10251/12890.

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El propósito de esta tesis doctoral fue evaluar la influencia de los diferentes procesos de gestión de residuos, tales como la valorización material, energética y biológica de dos poliésteres clave de la industria del embalaje: el actual no-renovable poli (tereftalato de etileno) (PET) y el potencial candidato para sustituirlo en un futuro próximo, la polilactida (PLA) de base renovable. Se utilizaron diversas plantas piloto para simular las condiciones de la degradación sufrida por PET y PLA en el reciclado mecánico, la pirólisis, la combustión y el enterramiento en suelo. Los cambios fueron monitorizados por calorimetría diferencial de barrido (DSC), análisis dinámico-mecánico-térmico (DMTA), análisis termogravimétrico (TGA), espectrometría infrarroja con transformada de Fourier (FTIR), espectroscopia de correlación 2D-IR para el análisis de gases (EGA), espectrometría de masas MALDI-TOF, microscopía electrónica de barrido (SEM), índice de fluidez de masa fundida (MFR), ensayos de tracción e impacto Charpy y viscosimetría. Se han propuesto, desarrollado y aplicado diversas estrategias y procedimientos analíticos para establecer parámetros fiables para ser utilizados como indicadores de la degradación y por tanto controlar la influencia de cada proceso de valorización en la calidad del material. El comportamiento de PET y PLA reciclados mecánicamente se evaluó en base a sus propiedades químicas, microestructurales, mecánicas y térmicas. Se observó una pérdida general de prestaciones de PET y PLA reprocesado una vez y dos veces, respectivamente. Además, las propiedades de los materiales reciclados de PLA fueron mejores en términos relativos a los productos reciclados de PET. Las descomposiciones térmica y termo-oxidativa causadas por los procesos de pirolisis y combustión se evaluaron sobre la estabilidad térmica, gases emitidos y cinéticas de descomposición. Se destaca el uso de la combustión controlada para ambos polímeros, ya que se necesita menos energía para iniciar la descomposición, y la mezcla de gases que se desprenden es más homogénea.
Badía Valiente, JD. (2011). Strategies and analytical procedures for a sustainable plastic waste management. An application to poly (ethylene terephthalate) and polylactide in the packaging sector [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/12890
Palancia

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Mlwilo, Nolasco Anton. "Radiometric characterisation of vineyard soils, Western Cape, South Africa." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6358_1318594333.

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This study is aimed at investigating the feasibility of using the radiometric technique as an alternative to traditional methods for determining soil physico-chemical parameters which are important for terroir characterization. In-situ and ex-situ radiometric analyses of soil from three vineyard blocks of Simonsig Wine Estate in the Stellenbosch district (Western Cape, South Africa) were studied. A mobile MEDUSA gamma-ray detection system comprising a CsI(Na) crystal (length 15 cm, diameter 7 cm) and associated electronics mounted on a portable trolley were used for partial terroir characterisation. Thereafter activity concentrations of 40K, 232Th series and 238U series in soil (top ~30 cm) from the measured MEDUSA spectra (0 â 3 MeV) were extracted by means of the full-spectrum analysis (FSA) method. A lead-shielded HPGe detector was used for analyzing collected soil samples while soil physico-chemical parameters were analysed using standard methods at research and commercial laboratories.

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Klus, Petr 1985. ""The Clever machine"- a computational tool for dataset exploration and prediction." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/482051.

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The purpose of my doctoral studies was to develop an algorithm for large-scale analysis of protein sets. This thesis outlines the methodology and technical work performed as well as relevant biological cases involved in creation of the core algorithm, the cleverMachine (CM), and its extensions multiCleverMachine (mCM) and cleverGO. The CM and mCM provide characterisation and classification of protein groups based on physico-chemical features, along with protein abundance and Gene Ontology annotation information, to perform an accurate data exploration. My method provides both computational and experimental scientists with a comprehensive, easy to use interface for high-throughput protein sequence screening and classification.
El propósito de mis estudios doctorales era desarrollar un algoritmo para el análisis a gran escala de conjuntos de datos de proteínas. Esta tesis describe la metodología, el trabajo técnico desarrollado y los casos biológicos envueltos en la creación del algoritmo principal –el cleverMachine (CM) y sus extensiones multiCleverMachine (mCM) y cleverGO. El CM y mCM permiten la caracterización y clasificación de grupos de proteínas basados en características físico-químicas, junto con la abundancia de proteínas y la anotación de ontología de genes, para así elaborar una exploración de datos correcta. Mi método está compuesto por científicos tanto computacionales como experimentales con una interfaz amplia, fácil de usar para un monitoreo y clasificación de secuencia de proteínas de alto rendimiento.

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46

Ribeiro, Emerson Santos. "Análise da qualidade da água no Rio Catu da Bacia Hidrográfica do Rio Pojuca - Bahia." Universidade Catolica de Salvador, 2011. http://hdl.handle.net/123456730/311.

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No Brasil, ações antrópicas como o lançamento de esgotos, desmatamento de mata ciliar e uso inadequado de defensivos agrícolas, têm causado danos à qualidade ambiental e da água dos rios, sobretudo quando estes rios cortam os grandes centros urbanos. Destaca-se entre as atividades que impactam negativamente estes corpos d’água o lançamento in natura de esgotos domésticos e efluentes industriais. Devido a que quando estes não são tratados, além de degradar a qualidade da água do rio, têm um grande impacto sobre as atividades das comunidades ribeirinhas. O objetivo geral da pesquisa foi analisar e diagnosticar o estado de poluição do Rio Catu no Estado da Bahia e propor medidas para melhorias na qualidade de sua água. A pesquisa constou de um questionário que levantou o uso das comunidades ribeirinhas do Rio Catu, levantamento dos pontos de lançamentos de esgotos industriais e residenciais, através da utilização de GPS e a análise da qualidade da água em 4 pontos do rio em dois períodos em maio e outubro de 2010 . As análises foram realizadas nos laboratórios do SENAI e do Laboratório de Estudos em Meio Ambiente - LEMA da UCSAL, assim como dos cálculos obtidos por meio do Índice de Qualidade de Água (IQA) que são uma forma simples de indicar a qualidade de sistemas hídricos. Neste trabalho é proposta a implementação da ponderação proveniente dos IQAs na metodologia de avaliação de qualidade de águas. Conclui-se que os lançamentos de esgotos e efluentes industriais causam impactos negativos à qualidade da água do Rio Catu, tendo consequências sobre a fauna e a flora do Rio e as comunidades ribeirinhas que precisam do rio para alguma atividade.
In Brazil, human activities such as dumping of sewage, deforestation of riparian vegetation and inappropriate use of pesticides, have caused damage to the environment and water quality of rivers, especially when these rivers cut the large urban centers. The launch of fresh domestic sewage and industrial effluents are among the activities that negatively impact these water bodies. When they are not treated it degrades the quality of river water, and this have a great impact on the activities of coastal communities. The aim of the research was to analyze and diagnose the state of pollution of the River Catu in Bahia and propose measures to improve the quality of the water. The survey consisted of a questionnaire that raised the use of the riverside communities of Rio Catu, a survey that pointed sewage spills from industrial and residential projects, through the use of GPS, and analysis of water quality in four sections of the river in two periods, in May and in October 2010. Analyses were performed in the laboratories of SENAI and Laboratory Studies in Environment - LEMA of UCSAL, as well as of the results obtained through the Water Quality Index (IQA) that are a simple way to indicate the quality of water systems. This paper proposes the implementation of the weighting of IQAS as a methodology to assess water quality. It is concluded that the release of sewage and industrial effluents cause negative impacts to water quality of Rio Catu, having an impact on the flora and fauna of the river and coastal communities that need the river for some activity.

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47

Diagne, Ndeye Wemsy. "Le nettoyage : une étape-clef pour une production durable par procédé à membrane : réflexion sur le lien entre conditions de production et nettoyabilité d'une membrane PES de l'industrie laitière." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-01019725.

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Le nettoyage en place des membranes en industrie agro-alimentaire est une opération cruciale qui, outre les exigences de sécurité sanitaire des installations et des produits traités doit permettre de restaurer les performances de la filtration (sélectivité, flux) en éliminant le colmatage formé pendant l'étape de production. Malheureusement cette étape repose encore sur des bases empiriques et non optimisées. A cause d'un manque de notions fondamentales, elle est encore pressentie comme un frein à l'utilisation massive des procédés membranaires. Une démarche originale a été menée dans le cadre de cette thèse incluant la réflexion sur l'incidence des paramètres hydrodynamiques des conditions de production sur la cohésion du dépôt colmatant et plus particulièrement de sa fraction irréversible, dont la nettoyabilité est étudiée. Pour fonder cette démarche, une étude comparée du colmatage et du nettoyage au flux limite et au flux critique a été réalisée en intégrant le rôle de la physico-chimie et de l'hydrodynamique pendant la phase de production. cette étude s'inscrit dans un cadre d'éco-conception de procédé, avec une analyse de cycle de vie réalisée afin d'estimer l'impact environnemental de l'étape de nettoyage via divers scénarii simplifiés.

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48

Niemczyk, Anna Irena. "Synthesis of a novel crosslinked polyvinylpyrrolidone carriers to enhance the dissolution of poorly-water soluble drugs : studies on the synthesis of novel crosslinked polyvinylpyrrolidone polymers and analysis of their influence on the physico-chemical properties of ibuprofen dispersed within these carriers." Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553143.

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Improving dissolution of poorly-water soluble drugs and hence their bioavailability represents one of the major challenges within pharmaceutical formulation design. Commercial crosslinked polyvinylpyrrolidone (PVP) attracts attention as a drug carrier since it can increase wettability, specific surface area and dissolution rate of poorly-water soluble drugs. Therefore, crosslinked PVP appears to be a promising carrier especially for Biopharmaceutical Classification System (BCS) Class 11 drugs featuring high permeability but poor solubility. The aim of the studies was to synthesize novel crosslinked PVP with extended potential for hydrogen bonding interactions and to evaluate its application as a drug carrier in physical mixtures with ibuprofen (IB). In particular, the thesis seeks to elucidate the nature of IB-PVP interactions, especially in terms hydrogen bonding, drug crystallinity disruption and enhancements in IB dissolution rate. The studies involved synthesis of novel PVP crosslinkers with hydrogen bonding potential. The target structure of the novel crosslinkers was composed of two NVP units which were linked by different lengths of oligo ether chains. The multi-step synthesis of the novel crosslinkers afforded material with an acceptable overall yield of 27%, while in the case of an alternate one-step synthesis the yield did not exceed 9%. A series of free radical polymerisation reactions were carried out affording six novel crosslinked PVP polymers varying in the length of the oligo ether chains ("5 PVP" and "7 PVP") and in the density of crosslinking (the crosslinker content in the feed mixture: 1 wt%, 2.5 wt%, 5 wt%), i.e.: 7 PVP 5%, 7 PVP 2.5%, 7 PVP 1% and 5 PVP 5%, 5 PVP 5%, 5 PVP 5%. Six homogenous physical mixtures of IB (30 wt%) with novel crosslinked PVP polymers and a control mixture containing commercial crosslinked PVP were prepared using a Turbula mixer. FT-IR spectroscopic analysis of the physical mixtures confirmed the presence of hydrogen bonding interactions between IB and all the polymers. The novel PVP polymers with the highest contents of crosslinker were the most effective in disrupting IB crystallinity and in enhancing IB dissolution rate. Increase of the crosslinker contents in the novel PVP could enhance hydrogen bonding interactions which in turn improved the PVP ability to disrupt ibuprofen crystallinity. This subsequently conferred a dissolution rate advantage for physical mixtures IB-PVP over the sample of pure crystalline lB. Notably, the novel crosslinked PVP polymers had greater capacity to disrupt IB crystallinity and improve its dissolution than commercial crosslinked PVP XL 10 (Polyplasdone XL-10, ISP Technologies Inc.).The DSC data showed that the sample IB+7PVP5% had the lowest drug crystallinity (only 30%) and indeed yielded the fastest dissolution rate, while the sample IB+PVPXL 10 with the highest content of crystalline IB (62%) resulted in the lowest IB dissolution. In summary, the studies provide a method of modifying hydrogen bonding potential of crosslinked PVP to improve PVP properties as a carrier of poorly-water soluble drugs, especially in terms of disrupting drugs crystallinity and enhancing their dissolution rate. Improving dissolution of poorly-water soluble drugs and hence their bioavailability represents one of the major challenges within pharmaceutical formulation design. Commercial crosslinked polyvinylpyrrolidone (PVP) attracts attention as a drug carrier since it can increase wettability, specific surface area and dissolution rate of poorly-water soluble drugs. Therefore, crosslinked PVP appears to be a promising carrier especially for Biopharmaceutical Classification System (BCS) Class 11 drugs featuring high permeability but poor solubility. The aim of the studies was to synthesize novel crosslinked PVP with extended potential for hydrogen bonding interactions and to evaluate its application as a drug carrier in physical mixtures with ibuprofen (IB). In particular, the thesis seeks to elucidate the nature of IB-PVP interactions, especially in terms hydrogen bonding, drug crystallinity disruption and enhancements in IB dissolution rate. The studies involved synthesis of novel PVP crosslinkers with hydrogen bonding potential. The target structure of the novel crosslinkers was composed of two NVP units which were linked by different lengths of oligo ether chains. The multi-step synthesis of the novel crosslinkers afforded material with an acceptable overall yield of 27%, while in the case of an alternate one-step synthesis the yield did not exceed 9%. A series of free radical polymerisation reactions were carried out affording six novel crosslinked PVP polymers varying in the length of the oligo ether chains ("5 PVP" and "7 PVP") and in the density of crosslinking (the crosslinker content in the feed mixture: 1 wt%, 2.5 wt%, 5 wt%), i.e.: 7 PVP 5%, 7 PVP 2.5%, 7 PVP 1% and 5 PVP 5%, 5 PVP 5%, 5 PVP 5%. Six homogenous physical mixtures of IB (30 wt%) with novel crosslinked PVP polymers and a control mixture containing commercial crosslinked PVP were prepared using a Turbula mixer. Notably, the novel crosslinked PVP polymers had greater capacity to disrupt IB crystallinity and improve its dissolution than commercial crosslinked PVP XL 10 (Polyplasdone XL-10, ISP Technologies Inc.).The DSC data showed that the sample IB+7PVP5% had the lowest drug crystallinity (only 30%) and indeed yielded the fastest dissolution rate, while the sample IB+PVPXL 10 with the highest content of crystalline IB (62%) resulted in the lowest IB dissolution. In summary, the studies provide a method of modifying hydrogen bonding potential of crosslinked PVP to improve PVP properties as a carrier of poorly-water soluble drugs, especially in terms of disrupting drugs crystallinity and enhancing their dissolution rate.

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49

Barbosa, Fabio Rocha. "DiagnÃstico de Falhas Incipientes a Partir das Propriedades FÃsico-QuÃmicas do Ãleo Isolantes em Transformadores de PotÃncia Como MÃtodo Alternativo Ã AnÃlise de Gases Dissolvidos." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9189.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
O diagnÃstico de falhas incipientes em transformadores de potÃncia imersos em Ãleo estÃ diretamente relacionado Ã avaliaÃÃo das condiÃÃes do sistema de isolamento. Este estudo aborda a relaÃÃo entre os gases dissolvidos no Ãleo e a qualidade do Ãleo mineral isolante utilizado em transformadores de potÃncia. As redes neurais artificiais sÃo utilizadas na abordagem da avaliaÃÃo das condiÃÃes operacionais do Ãleo isolante em transformadores de potÃncia, que Ã caracterizada por um comportamento dinÃmico nÃo-linear. As condiÃÃes de operaÃÃo e a integridade do sistema de isolamento de um transformador de potÃncia podem ser inferidas atravÃs das anÃlises fÃsico-quÃmicas e cromatogrÃficas (AnÃlise de GÃs Dissolvido). Estes ensaios permitem estabelecer procedimentos de operaÃÃo e manutenÃÃo do equipamento e normalmente sÃo realizados simultaneamente. Esta tese de doutorado propÃe um mÃtodo que pode ser usado para extrair informaÃÃes cromatogrÃficas usando as anÃlises fÃsico-quÃmicas atravÃs de redes neurais artificiais. As anÃlises atuais das propriedades fÃsico-quÃmicas fornecem apenas diagnÃstico do estado do Ãleo, o que nÃo permite o diagnÃstico de falhas incipientes. Acredita-se que, as concessionÃrias de energia podem melhorar a confiabilidade na previsÃo de falhas incipientes a um custo menor com este mÃtodo, uma vez que apenas um ensaio Ã necessÃrio. Os resultados mostraram que esta estratÃgia Ã promissora com mÃdia de acertos em diagnÃsticos de falhas maiores que 72%. O objetivo deste trabalho Ã a aplicaÃÃo direta do diagnÃstico de falhas incipientes atravÃs da utilizaÃÃo de propriedades fÃsico-quÃmicas, sem a necessidade de fazer uma cromatografia do Ãleo.
The diagnosis of incipient fault in power transformers immerses in oil are directly related to the assessment of the isolation system conditions. This search is about the relationship between dissolved gases and the quality of the insulating mineral oil used in power transformers. Artificial Neural Networks are used to approach operational conditions assessment issue of the insulating oil in power transformers, which is characterized by a nonlinear dynamic behavior. The operation conditions and integrity of a power transformer can be inferred by analysis of physicochemical and chromatographic (DGA â Dissolved Gas Analysis) profiles of the isolating oil. This tests allow establishing procedures for operating and maintaining the equipment and usually are performed simultaneously. This work proposes a method that can be used to extract chromatographic information using physicochemical analysis through Artificial Neural Networks. The present analysis of physicochemical properties only provide a diagnostic tool for the oil quality, which does not allow the diagnosis of incipient faults. ItÂs believed that, the power utilities could improve reliability in the prediction of incipient failures at a lower cost with this method, since only one test is required. The results show this strategy might be promising with an average accuracy for diagnosis of faults greater than 72%. The purpose of this work is the direct implementation of the diagnosis of incipient faults through the use of physicochemical properties without the need to make an oil chromatography.

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50

Mori, Vânia. "Estudos eletroquímicos envolvendo diferente complexos de amin-rutênio e o ligante NO. Desenvolvimento de eletrodo modificado para análise de óxido nítrico." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-06022018-094507/.

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Neste trabalho foram realizados estudos eletroquímicos com complexos de rutênio do tipo trans-[Ru(NH3)4L1L2]n+, aos quais se coordenam ligantes apropriados visando à modelagem de estruturas capazes de atuar como \"captadoras\" de NO. A síntese e caracterização desses complexos foram feitas pelo grupo de pesquisa do Professor Dr. Douglas Wagner Franco, IQSC-USP. Estes complexos foram adequadamente imobilizados em eletrodos e microeletrodos de ouro com filme de óxido de molibdênio. Com isso, foi desenvolvido um sensor eletroquímico para NO em solução aquosa de tampão fosfato, simulando o pH fisiológico (pH ˜7,4). Os eletrodos modificados foram empregados na quantificação de NO em amostras de albumina bovina com peroxidonitrito na presença de tempo, verificando-se a produção de NO nesse meio. Essas amostras foram fornecidas pela Professora Dra Ohara Augusto, IQ-USP São Paulo. Os estudos referentes os complexos de rutênio visaram principalmente à determinação da velocidade de liberação do NO desses complexos, através do mecanismo EC. Para isso, utilizaram-se duas técnicas eletroquímicas, cronoamperometria de duplo degrau de potencial e voltametria com eletrodo rotativo de disco-anel. Além dos complexos coordenados com o ligante NO foram estudados complexos coordenados com o ligante sulfato. Os resultados obtidos pelas duas técnicas eletroquímicas foram concordantes, e estavam de acordo com o esperado, mediante aos estudos prévios realizados pelo grupo do Professor Dr. Douglas Wagner Franco. As constantes de velocidades encontradas situaram-se - na faixa de 10 a 10-3 s-1. Essas variações estão relacionadas com as propriedades químicas de cada ligante. Outro estudo eletroquímico realizado com a molécula de óxido nítrico em solução de tampão fosfato (pH ˜7,4) foi feito no intuito de determinar a concentração exata de uma solução saturada de NO. Para isso, utilizou-se a técnica de cronamperometria, com eletrodo de trabalho um microeletrodo de platina de raio igual a 25 µm. A concentração da solução saturada de NO, foi de (2,1 ± 0,3) mmolL-1. Os resultados da concentração foram confirmados pelo método clássico titulação volumétrica, no qual obteve-se o valor da concentração de (1,95 ± 0,02) mmolL-1. Esses resultados estão de acordo com resultados descritos na literatura.
The trans-[Ru(NH3)4NOL]3+ (L = 4-NH2py, Him, L-hist, 4-pic, py, 4-Clpy, nia, isn, 4-CNpy and pz) complexes were eletrochemically investigated by using double potencial step chronoamperometry and rotating ring-disc electrode voltammetry. Values for the rate of NO substitution by water molecule ranged from 0.02 s-1 (4-pic) to 0.34 s-1 (pz) at 25ºC. Gold surfaces were modified with an electrochemically deposited layer of non-stoichiometric molybdenum oxides. At these surfaces, trans-[Ru(III)(NH3)4(4pic)SO4]+ complex was incorporated in a controlled way by cycling consecutively the potential in the range +0.50 to -0.25 V at pH ˜ 3. Very reproducible voltammetric curves corresponding to the electrochemical process of the ruthenium complex were obtained, confirming the immobilisation of the material into the molybdenum oxide film. The anodic oxidation of nitric oxide at physiological pH ˜7.4 in phosphate buffer was investigated at the modified electrode containing the molybdenum oxide + trans-[Ru(III)(NH3)4(4pic)SO4]+ complex and an enhancement in the current response was observed compared to the signal at a bare electrode. The rate for NO electrochemical oxidation was dependent on the amount of catalytic ruthenium sites dispersed into the molybdenum oxide film, suggesting the participation of the metallic ion in an out-sphere mechanism. A linear relationship between current signals measured by square wave voltammetry and NO concentration was obtained in the 0 to 10 µM range. The applicability of the modified electrode as a sensor for real-time NO monitoring was also demonstrated.

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Dissertations / Theses on the topic 'Physico-chemical analyzes'

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