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1
Pereira, Thereza Mylene de Moura. "Caracteriza??o t?rmica (TG/DTG, DTA, DSC, DSC-fotovisual) de Horm?nios bioid?nticos (estriol estradiol)". Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13478.
Testo completoAbstract (sommario):
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Previous issue date: 2013-03-22Bioidentical hormones are defined as compounds that have exactly the same chemical and molecular structure as hormones that are produced in the human body. It is believed that the use of hormones may be safer and more effective than the non-bioidentical hormones, because binding to receptors in the organism would be similar to the endogenous hormone. Bioidentical estrogens have been used in menopausal women, as an alternative to traditional hormone replacement therapy. Thermal data of these hormones are scarce in literature. Thermal analysis comprises a group of techniques that allows evaluating the physical-chemistry properties of a drug, while the drug is subjected to a controlled temperature programming. The thermal techniques are used in pharmaceutical studies for characterization of drugs, purity determination, polymorphism identification, compatibility and evaluation of stability. This study aims to characterize the bioidentical hormones estradiol and estriol through thermal techniques TG/DTG, DTA, DSC, DSC-photovisual. By the TG curves analysis was possible to calculated kinetic parameters for the samples. The kinetic data showed that there is good correlation in the different models used. For both estradiol and estriol, was found zero order reaction, which enabled the construction of the vapor pressure curves. Data from DTA and DSC curves of melting point and purity are the same of literature, showed relation with DSC-photovisual results. The analysis DTA curves showed the fusion event had the best linearity for both hormones. In the evaluation of possible degradation products, the analysis of the infrared shows no degradation products in the solid state
Horm?nios bioid?nticos s?o compostos que t?m exatamente a mesma estrutura qu?mica e molecular dos horm?nios end?genos humanos. Acredita-se que a utiliza??o desses horm?nios pode ser mais segura e eficaz que os horm?nios n?o-bioid?nticos, pois a liga??o aos receptores no organismo se daria de forma semelhante aos horm?nios end?genos. Estrog?nios bioid?nticos v?m sendo utilizado, em mulheres na menopausa, como uma alternativa ? terapia de reposi??o hormonal tradicional. Dados t?rmicos desses horm?nios s?o escassos na literatura. A an?lise t?rmica ? um conjunto de t?cnicas que possibilita medir as propriedades f?sico-qu?micas de uma subst?ncia em fun??o da temperatura. As t?cnicas t?rmicas v?m sendo utilizadas na ?rea farmac?utica em diversas aplica??es, como na caracteriza??o de f?rmacos, determina??o do grau de pureza, identifica??o de polimorfismo, estudos de estabilidade e compatibilidade. Este trabalho tem como objetivo a caracteriza??o dos horm?nios bioid?nticos estradiol e estriol atrav?s das t?cnicas t?rmicas TG/DTG, DTA, DSC, DSC-fotovisual. A partir da an?lise das curvas TG, foi poss?vel calcular os par?metros cin?ticos para as amostras. Os dados cin?ticos mostraram boa correla??o entre os diferentes modelos empregados. Tanto para o estradiol como para o estriol, foi encontrada ordem zero de rea??o, o que possibilitou a constru??o das curvas de press?o de vapor. Dados das curvas DSC e DTA sobre ponto de fus?o e pureza s?o condizentes com a literatura, sendo poss?vel correlacionar estes resultados com o DSC-fotovisual. As an?lises das curvas DTA mostraram o evento de fus?o como o de melhor linearidade para os dois horm?nios. Na avalia??o dos poss?veis produtos de degrada??o, a an?lise do infravermelho mostra que n?o houve produtos de degrada??o no estado s?lido
2
Kopecký, Jan. "Určení kinetických parametrů reakcí pomocí DSC měření". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378413.
Testo completoAbstract (sommario):
The master thesis deals with DSC measurments a calculation of kinetic parameters. In the theoretical part, iron alotropy is briefly described, followed by a description of the DSC analysis itself. The thesis also includes division and derivation of isoconversional methods for calculating the activation energy. In the experimental part, a series of measurments is perfomed on pure iron prepared by Cold Spray method. In the paper the influence of deformation on the Curie temperature of the magnetic transformation in -Fe and transformation > is investigated. The activation energy is calculated for transformation > for different degrees of deformation. The degree of deformation is monitored by channeling contrast.
3
Hoffman, Roland. "Measuring ΔH Using DSC, TGA & DTA". TopSCHOLAR®, 1990. https://digitalcommons.wku.edu/theses/2500.
Testo completoAbstract (sommario):
The purpose of this study was to obtain greater accuracy in the measurement of the heat of reaction by combining data from various thermal analysis techniques. Conventional equations that calculate heat of reaction are limited because they do not take in to account mass change. Therefore, an enhanced equation was developed to integrate mass (weight) change to provide greater accuracy. The path chosen to implement this new equation employed simultaneous Thermogravimetric / Differential Thermal Analysis (TG/DTA) that could provide both ΔT and weight data simultaneously. Computer programs were written in C and Pascal languages to provide communication capabilities between computers and to calculate heat of reaction using various equations. This included a qualitative to quantitative (ΔT to ΔH) conversion which was performed to the DTA data file to which the enhanced equation was applied. Various samples were used to test and monitor the performance of the developed equations.
4
Černý, Štěpán. "Využití multi-echo sekvencí pro DSC-MRI". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242109.
Testo completoAbstract (sommario):
The task of this thesis is to study the subject of perfusion analysis based on dynamic imaging with T2/T2* contrast. The focus was on the acquisition commonly used for DSC-MRI and especially in the acquisition pulse sequences that use images with different echo time, so called Multi-echo sequence. Principles of dynamic measurement by magnetic resonance imaging, the role of contrast agents and their influence on the relaxation times are described. It also describes the problems perfusion analysis, measurement and mathematical modeling parameters entering to the convolution dependency for getting perfusion parametersIn the experimental part is developed automatic algorithm to gain curves relaxation time T2 *. Next, the synthetic data are created and tested robustness estimate perfusion parameters against noise. In the next phase of work there are compared real scanned objects with using a conversion with T2 * and free of T2*. In the last phase of work is compared influence of length of used echo times on concentration curves and after perfusion analysis influence on resulting perfusion parameters.
5
Kuběnová, Monika. "Hodnocení homogenity ingotů slitiny Ni-Ti metodou DSC". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216478.
Testo completoAbstract (sommario):
Alloy NiTi with nearequiatomic composition of nickel and titan belongs to a group of metal materials with a shape memory effect (Shape memory alloys). NiTi alloys are a guite attractive materials not only as practical shape memory alloys with hight strenght and ductility but also as those exhibiting unique physical properties. The production of these matrerials is complying with chemical composition. Final charakteristics of alloy are influenced by these bounderies and also by mechanical-heat treatment. This work deal with DSC evaluation of homogenity of ingot structure of NiTi alloy containing 50,8 at.% Ni. The alloy was melted in Y2O3 cricible. In the end the results of DSC method are compared to the microstructure of alloy obtained by SEM and TEM methods.
6
Porto, Dayanne Lopes. "Contribui??es sobre estudos t?rmicos (TG/DTG, DTA, DSC e DSC-Fotovisual) da rifampicina e seus principais produtos de degrada??o". Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13506.
Testo completoAbstract (sommario):
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Previous issue date: 2014-03-24Since its synthesis over 48 years rifampicin has been extensively studied. The literature reports the characterization of thermal events for rifampicin in nitrogen atmosphere, however, no characterization in synthetic air atmosphere. This paper aims to contribute to the thermal study of rifampicin through thermal (TG / DTG, DTA, DSC and DSC - FOTOVISUAL ) and non-thermal (HPLC, XRPD , IR - FTIR , PCA) and its main degradation products ( rifampicin quinone , rifampicin N-oxide 3- formylrifamicin). Rifampicin study was characterized as polymorph form II from techniques DSC, IR and XRPD. TG curves for rifampicin in synthetic air atmosphere showed higher thermal stability than those in N2, when analyzed Ti and Ea. There was characterized as overlapping events melting and recrystallization under N2 with weight loss in the TG curve, suggesting concomitant decomposition. Images DSCFotovisual showed no fusion event and showed darkening of the sample during analysis. The DTA curve in synthetic air atmosphere was visually different from DTA and DSC curves under N2, suggesting the absence of recrystallization and melting or presence only decomposition. The IV - FTIR analysis along with PCA analysis and HPLC and thermal data suggest that rifampicin for their fusion is concomitant decomposition of the sample in N2 and fusion events and recrystallization do not occur in synthetic air atmosphere. Decomposition products studied in an air atmosphere showed no melting event and presented simultaneously to the decomposition initiation of heating after process loss of water and / or solvent, varying the Ti initiating events. The Coats - Redfern , Madsudhanan , Van Krevelen and Herwitz - Mertzger kinetic parameters for samples , through the methods of OZAWA , in an atmosphere of synthetic air and / or N2 rifampicin proved more stable than its degradation products . The kinetic data showed good correlation between the different models employed. In this way we contribute to obtaining information that may assist studies of pharmaceutical compatibility and stability of substances
estudada. H? relatos de estudos focando o desenvolvimento de metodologias anal?ticas, novas aplica??es farmac?uticas, bem como, desenvolvimento de novas formas farmac?uticas. A busca pelo entendimento dascaracter?sticas f?sico-qu?micas das subst?ncias tem auxiliado no desenvolvimento de novos produtos farmac?uticos, com seguran?a, efic?cia e qualidade,fornecendo informa??es ?teis sobre s?ntese e armazenamento. Dentre os produtos de decomposi??o j? conhecidos para rifampicina, temos a rifampicina quinona, rifampicina N-?xido e 3-formilrifampicina, para tais, dados t?rmicos s?o escassos na literatura. As t?cnicas t?rmicas v?m sendo utilizadas na ?rea farmac?utica em diversas aplica??es, como na caracteriza??o de f?rmacos, determina??o do grau de pureza, identifica??o de polimorfismo, estudos de estabilidade, compatibilidade e cin?tica de degrada??o. Este trabalho tem como objetivo contribuir com o estudo t?rmico da rifampicina atrav?s das t?cnicas t?rmicas (TG/DTG, DTA, DSC, DSC-Fotovisual)e n?o t?rmicas, e seus principais produtos de degrada??o (rifampicina quinona, rifampicina N-?xido 3-formilrifamicina). A partir de an?lises DSC, DRX e FTIR foi poss?vel caracterizar a rifampicina estudada como polimorfo II. O conjunto de t?cnicas t?rmicas e n?o t?rmicas auxiliaram a verificar que parte da rifamipicina ? decomposta durante o processo de fus?o, em atmosfera de nitrog?nio, bem como que, os eventos de fus?o e recristaliza??o n?o ocorrem em atmosfera de ar sint?tico passando a amostra diretamente a decomposi??o. Os produtos de decomposi??o estudados, quando em atmosfera de ar, n?o apresentaram evento de fus?o e, apresentaram v?rios passos de decomposi??o, com a ocorr?ncia de eventos exot?rmicos e endot?rmicos. A partir de curvas TG din?micas, foi poss?vel calcular os par?metros cin?ticos para as amostras, atrav?s dos m?todos de OZAWA, Coats-Redfern, Madsudhanan, Van Krevelen e Herwitz-Mertzger, em atmosfera de ar sint?tico e/ou nitrog?nio. Os dados cin?ticos mostraram boa correla??o entre os diferentes modelos empregados. Tanto para rifampicina quanto os produtos de degrada??o estudados, foi caracterizado rea??o de ordem um
7
Gerothanassis, I. P. "Application of a DSc in the School of Chemical Sciences". Thesis, University of East Anglia, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539366.
Testo completo
8
Sprunt, John. "Structural polymorph characterisation using fibre-optic linked FT-Raman-DSC". Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267561.
Testo completoAbstract (sommario):
A low-cost fibre-optic probe was constructed, and used to provide an optical link between an FT-Raman spectrometer and a Differential Scanning Calorimeter (DSC). The resulting Simultaneous Raman-DSC (SRD) method combines the vibrational structural information of FT-Raman spectroscopy with the thermal data of DSC, which is particularly useful for characterisation of samples exhibiting temperature- and thermal conditioning-dependent polymorphic (i. e. structural) changes. The samples chosen for method development and structural study were ammonium nitrate (NH4NO3), the triglyceride sn-1,3-distearoyl-2-oleoyl glycerol (SOS), cocoa butter (which is chiefly composed of a mixture of monounsaturated triglycerides), and some chocolates of differing composition. The bifurcated `6-around-i' parallel fibres probe design allowed Raman spectra to be collected from unencapsulateds amplesi n the normal DSC sample position without extensive mechanical modifications or the use of extra optical components. Method development using the above samples showed that the combined SRD sampling has various effects on collected data. With this probe design, a "glass background" spectrum is superimposed on the Raman spectrum, and must be subtracted using the spectrometer software. At raised temperatures, a thermal emission feature appears in the Raman spectrum at high wavenumber shift. The incident laser light was found to raise sample temperatures by around 1.5-3K. Raman spectra were therefore collected with samples held around 10K below transition onset temperatures. The necessary lack of encapsulation resulted in broadened thermal transitions in DSC heating curves, and potential heat loss due to radiative emission at raised temperatures. However, for samples analysed near room temperature, onset melting points for transitions with the laser off were not significantly altered by SRD sampling. Ammonium nitrate is often irreproducible in it's exact phase transition thermal behaviour. SRD analysis showed the expected phases IV, III, II and I at room temperature and above at normal atmospheric pressure. Raman spectra could then be unambiguously assigned to the respective phases. Comparison with previous literature work allows the spectral changes seen to be interpreted using symmetry-based rationalisations. The triglyceride SOS was found to conform well to the literature thermal behaviour. SRD analysis showed DSC heating curves with onset melting points and features identifying the polymorphs produced as a, , y, ß', ß2 and [il. A literature survey allows the corresponding Raman spectra to be interpreted in the light of structural packing suggestions made by workers using various other analytical techniques. Cocoa butter was successfully prepared in states 3,4,5 and 6 of the six polymorphs known to exist. DSC melting behaviour and heating curve shapes were used to unambiguously relate Raman spectra to the individual polymorphs. Interpretation of Raman spectra was based on the SOS triglyceride SRD results, together with structural packing suggestions from the literature. A selection of chocolate samples were also analysed by SRD. Those with a high cocoa butter content were found to approximate well to the thermal and structural behaviour of pure cocoa butter.
9
Strutz, Jean Carlos 1982, Sérgio Vidal Garcia 1974 Oliveira e Universidade Regional de Blumenau Programa de Pós-Graduação em Engenharia Elétrica. "Conversor CC-CC elevador trifásico controlado digitalmente com DSC 56f8323 /". reponame:Biblioteca Digital de Teses e Dissertações FURB, 2011. http://www.bc.furb.br/docs/DS/2011/351406_1_1.PDF.
Testo completo
10
Casaus, Dana M. "DSC, FTIR and SEM Characterization of As-received Colored Elastomeric Chains". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236179988.
Testo completo
11
Yuan, Shuming. "Optical-DSC for analysis of energy processes in transparent microscopic systems". Access restricted to users with UT Austin EID, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3037031.
Testo completo
12
Li, Hongbo. "FEM analysis with DSC modeling for materials in chip-substrate systems". Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280363.
Testo completoAbstract (sommario):
In electronic packaging, solder joints in surface mount technology are used for not only electrical connections, but mechanical connections as well. Due to the mismatch of the coefficients of thermal expansion of different components in chip-substrate systems, solder joints under thermal cycles could develop thermal stress inside and therefore experience fatigue failure after a certain number of load cycles. In this work, the disturbed state concept (DSC) model, a unified and hierarchical approach to model a variety of materials such as soils, rocks, ceramics, metals, and alloys, was appropriately modified to characterize a 63Sn-37Pb solder. This includes a modified hardening function that eliminates some inconsistency in the HISS-delta0 model when the bonding stress is nonzero, and a different fully adjusted state that is properly assumed from test data on the 63Sn-37Pb solder. A generalized computer procedure was then developed for 3-D constitutive level back prediction with the DSC model. In addition, a modified computer procedure for parameter determination was proposed and implemented to calculate the relative intact stress-strain curve for simple shear test data automatically. The above procedures for parameter determination and back prediction were used to model simple shear tests of the 63Sn-37Pb solder at different temperatures and strain rates. Based on material properties determined from test data at different combinations of temperature and strain rate, constitutive level back predictions were performed for each test data set using (1) specific material properties and (2) temperature and rate dependent material properties. Further, a 3-D DSC FEA (finite element analysis) program was used to simulate the same stress-strain behaviors of solder joints at different temperatures and strain rates. The results from back prediction and 3-D FEA simulation show that the test data have been better characterized by the modified DSC model. Moreover, 2-D and 3-D DSC FEA programs were employed to study the fatigue failure of a 144-Pin PBGA solder ball under cyclic thermomechanical loading. An accelerated-approximate procedure was incorporated into the 3-D FEA program to reduce the computational effort for fatigue analysis. Results of 3-D FEAs show that the 3-D geometry of a solder joint has significant influences on its fatigue life. The comparison of 2-D and 3-D results with the test results for the 144-pin PBGA solder ball indicates the FEA results are consistent with the initiation of failure observed in laboratory test. In addition, failure criteria based on fractional volume were also proposed for 2-D and 3-D FEAs by calibration of the available test results.
13
Maggiolino, Stefano. "Un nuovo dispositivo per analisi microcalorimetriche nel settore biologico: DSC-MEMS". Doctoral thesis, Università degli studi di Trieste, 2008. http://hdl.handle.net/10077/2765.
Testo completoAbstract (sommario):
2006/2007Il seguente lavoro di tesi di dottorato è inerente alla progettazione, modellizazione, caratterizzazione di uno sensore MEMS (Micro Electro Mechanical System) per misure calorimetriche su cellule. Sono stati progettati diversi dispositivi simulandone, in diversi casi, le scelte progettuali atte a migliorare le caratteristiche del sensore. Sono state simulate anche scelte che a causa della tecnologia usata non sono state applicate, ma con tecnologie differenti potrebbero andare a migliorare il sensore. In conclusione tutte le scelte progettuali indagate, ed in alcuni casi anche applicate ad un dispositivo realizzato, si possono suddividere in tre tipologie di scelte: scelta di materiali, scelta di soluzioni tecniche per ridurre la dispersione termica e scelte per incrementare il segnale direttamente dal dispositivo Dopo aver progettato e simulato i dispositivi sono andato studiare un metodo per poter rilevare il segnale elettrico adatto ad acquisire intensità molto basse. Lo studio è partito da semplici amplificatori e poi si è rivolto a metodi atti a minimizzare il rumore come l’amplificatore ad aggancio di frequenza coordinato con l’optical chopper e con l’electrical chopper. Questi sistemi alla fine sono stati studiati in modo tale da ottenere una massimizzazione del segnale. Sono stati caratterizati i dispositivi realizzati, andando a cercare la minima potenza termica sensibile da questi. I risultati sono che utilizzando le tecniche sopra descritte, sono riuscito a misurare potenze dell’ordine dei 25 nW valore molto promettente. I dispositivi sono stati testati anche in liquido e i risultati ottenuti dimostrano che non ci sono effetti di cortocircuitazione tra gli elettrodi e quindi possono essere usati tranquillamente in ambiente acquoso. In conclusione in questo lavoro di dottorato è stato sviluppato un dispositivo atto a misurare potenze termiche erogate dell’ordine di decine di nW, si sono identificati ed ottimizzati processi di self-reparing per ripristinare dispositivi non conformi al progetto, si sono identificate delle metodologie per effettuare la caratterizzazione dei dispositivi applicabili poi in seguito anche alla misura vera e propria, è stato intrapreso lo studio di una ottimizzazione del processo per la fabbricazioni di barriere da fotopolimerizzazione al laser e sono state proposte delle soluzioni, testate solamente via simulazione ad elementi finiti, che garantirebbe degli incrementi sulla intensità del segnale notevoli.
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14
Fraga, Rivas Iria. "Study of thermal transitions in polymers by a multifrequency modulated DSC technique". Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/73029.
Testo completoAbstract (sommario):
Differential Scanning Calorimetry (DSC) is one of the most widely used thermal analysis techniques for the study of transitions and relaxation processes
in polymers and also in other materials. It measures the heat flow as a function of time and/or temperature, and determines the energy released or
absorbed by a sample when it is heated (cooled) or maintained at a constant temperature. Its advantages are that it is fast and sensitive, the amount of
sample needed is small (~mg), it could be in the liquid or solid state and the sample preparation is easier than for some other techniques. Nevertheless,
it present some drawbacks, such as not being able to separate different overlapping transitions that happen in the same temperature range, the
difficulty of detecting very weak transitions, or the requirement for multiple experiments to determine heat capacities that increases the experimental
time needed.
Temperature modulated DSC techniques (TMDSC) were introduced in the market more than 16 years ago. In these techniques a periodic temperature
modulation of small amplitude is superimposed on the underlying rate of conventional DSC. This superposition gives two different heating rates: the
underlying and the instantaneous due to the sinusoidal signal, thus permitting a better resolution and sensitivity (in DSC a better resolution gives a
worse sensitivity and vice versa) and the evaluation of the heat capacity in real time. TMDSC is able to determine not only the total heat flow but also its
two individual components usually referred to as “reversing” and “non-reversing”, thus it is possible to separate overlapped transitions. Although
TMDSC offers more information than that available by DSC it also shows some drawbacks as the use of lower underlying heating rates than in
conventional DSC which leads to longer experiments, or the requirement of making a separate scan for each frequency if one wishes to study, for
example, the frequency dependence of a certain phenomenon.
More recently, in 2005, TOPEM, a new technique of TMDSC from Mettler-Toledo, was commercialised. Instead of being based upon a periodic
modulation of the heating rate, as is the situation with other TMDSC techniques, TOPEM uses a stochastic modulation of the heating or cooling rate by
means of random pulses of temperature. This stochastic perturbation introduces a broad frequency spectrum in the response, which implies that
TOPEM is apparently able to determine the complex heat capacity over a range of frequencies in a single scan.
In the present thesis, a detailed description of the bases and operation of TOPEM is presented, showing the differences between the other calorimetric
techniques, DSC and TMDSC. All the parameters which define an experiment and the parameters needed to make an evaluation of the experimental
response are explained.
The glass transition of polycarbonate is selected to make an initial study of the influence of all the different parameters (experimental and calculation) on
the results of an experiment. Different samples are employed and different experiments by TOPEM and ADSC (TMDSC technique specific of Mettler-
Toledo) are performed and compared. The limits and advantages offered by TOPEM are observed and presented here, and with a more profound
understanding of the technique as a result, additional materials and transitions are studied.
In the next part, an epoxy resin with a diamine is selected to be studied. The vitrification during the isothermal cure is studied by TOPEM. The results
are again compared with those obtained by TMDSC and the additional information obtained is analyzed and compared with additional results obtained
from the literature. With the aim to confirm some experimental data observed, a simulation is made with MATLAB to confirm the experimental results. It
is found that the theoretical results not only predict the calorimetric data, but also those obtained from dielectric analysis at higher frequencies which
were extracted from the literature.
In the next part, the same epoxy resin with a diamine is selected. The vitrification and devitrification during the non-isothermal cure is analyzed by
TOPEM. The results obtained permit to construct a CHT diagram (conversion-time-temperature) which characterized the system. As in the previous
case a simulation is made with MATLAB and the theoretical results obtained compare well with the experimental data.
Finally, some preliminary experiments related to other transitions are presented and are planned to be studied in the future.La calorimetría diferencial de barrido (DSC) es una técnica ampliamente utilizada desde el año 1963 en la caracterización térmica de polímeros y otros materiales. En DSC se mide el calor absorbido o emitido por una muestra cuando es sometida a un programa de calentamiento (enfriamiento) o bien es mantenida a una temperatura constante. Sus ventajas es que es una técnica rápida, con gran sensibilidad, no requiere una preparación previa de las muestras, el tamaño de las mismas es pequeño (~mg) y pueden analizarse en estado líquido o sólido. Sin embargo, presenta algunas desventajas: no es posible detectar transiciones muy débiles, ni separar aquellas que aparecen superpuestas en el mismo rango de temperaturas y para la determinación de capacidades caloríficas exige la realización de varios experimentos separados lo que se traduce en un tiempo de experimentación en ocasiones muy largo. Hace 15 años comenzó a comercializarse la calorimetría diferencial de barrido con temperatura modulada (TMDSC). Lo que la diferencia de la calorimetría DSC convencional es que al tipo de barrido utilizado en DSC se superpone una señal periódica sinusoidal de modulación de temperatura de pequeña amplitud. Esta superposición da lugar a dos tipos de velocidad: una es la velocidad base de calentamiento (enfriamiento) y la otra de superposición de la señal modulada, algo que proporciona ciertas ventajas. Por ejemplo ofrece al mismo tiempo una buena resolución y una buena sensibilidad (en DSC la mejora de la sensibilidad lleva asociada pérdida de resolución y viceversa) o la evaluación de la capacidad calorífica a tiempo real. La TMDSC permite separar el flujo de calor total en dos componentes, reversing y non-reversing, permitiendo así separar transiciones que aparezcan superpuestas. Aunque si bien la TMDSC ofrece más información que el DSC convencional también presenta algunas desventajas como son el uso de velocidades más lentas que en DSC lo que implica tiempos de experimentación largos, o la necesidad de hacer un barrido para cada frecuencia en el caso de querer estudiar la dependencia en frecuencias de un determinado fenómeno. En el año 2005, se comenzó a comercializar TOPEM, una técnica también de temperatura modulada de Mettler-Toledo, en la que la modulación de la temperatura en lugar de ser periódica es estocástica, lo que introduce un amplio espectro de frecuencias en la respuesta cuya principal ventaja es que permite analizar la capacidad calorífica de una muestra en un rango de frecuencias realizando sólo un único barrido. En la presente tesis se ofrece una descripción de las bases del funcionamiento de TOPEM, mostrando las diferencias que presenta respecto a las mencionadas técnicas calorimétricas DSC y TMDSC. Se da una explicación detallada de todos parámetros que definen un experimento, así como los necesarios para realizar el cálculo de la respuesta experimental obtenida y otros parámetros importantes a tener en cuenta al utilizar TOPEM. En un primer estudio se selecciona la transición vítrea del policarbonato para comenzar a trabajar con la nueva técnica. Con diferentes muestras y realizando experimentos tanto de TOPEM como de ADSC (nombre de la técnica TMDSC específica de la casa comercial Mettler-Toledo) se comparan los resultados obtenidos con ambas técnicas. Se realiza un minucioso análisis de la influencia de los parámetros experimentales y de evaluación en los resultados obtenidos. Se observan y presentan los límites y ventajas ofrecidos por TOPEM y se establece una metodología de experimentación y evaluación con el fin de trabajar con otros materiales y transiciones. En la siguiente parte, se selecciona una resina epoxi con una diamina, y se aplica la técnica a la vitrificación durante el curado isotermo. Los resultados se comparan con los obtenidos por TMDSC y la información adicional obtenida es analizada y comparada con resultados extraídos de la bibliografía. Con el fin de confirmar algunos datos, se realizó una simulación con MATLAB que además de coincidir con los resultados experimentales previos, también coincide con diferentes resultados obtenidos con análisis dieléctrico a más altas frecuencias. En la siguiente parte, la misma resina epoxi con la diamina es sometida a curados no –isotermos para estudiar su vitrificación y posterior devitrificación. Se comprobaron las ventajas ofrecidas por TOPEM y se construyó un diagrama CHT (conversión-tiempo-temperatura) para caracterizar el sistema. Como en el caso anterior, una simulación realizada con MATLAB predice los resultados obtenidos experimentalmente. Por último, se presentan algunos experimentos previos realizados con diversos materiales en los que se obtienen interesantes resultados para ser ampliados y analizados en el futuro.
15
Gundogar, Sati Asli. "Thermal Characterization And Kinetics Of Crude Oils By Tga And Dsc Methods". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611502/index.pdf.
Testo completoAbstract (sommario):
In recent years, the application of thermal analysis to study the combustion and pyrolysis behavior of fossil fuels has gained a wide acceptance because of its significance for industry and economy. In this thesis, the thermal and kinetic analysis of different origin crude oil samples are performed by two well-known thermal analysis techniques: Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG/DTG). The investigation of combustion and pyrolysis behaviors, kinetic analysis of oil samples and the determination of heating rate effect are the main objectives of this study. Six different crude oils from the Southeastern region of Turkey are analyzed throughout the study. All experiments are performed at different heating rates (5, 10 and 15ºC/min) and air is used for combustion and nitrogen for pyrolysis experiments. In combustion experiments, TGA and DSC techniques indicate that the combustion process of crude oils studied is composed of two main reaction regions. These are low-temperature (LTO) and high-temperature oxidation (HTO) regions. In LTO, huge mass loss occurs (from 69 to 87 %) due to high amount of free moisture and volatile hydrocarbons contained in oil samples. Combustion reactions continue up to 900 K. On DSC curves, two exothermic regions of oxidation regimes are detected. Comparing TG/DTG and DSC curves, it can be understood that the mass loss under combustion is accompanied by exothermic peaks because of the oxidative degradation of crude oil components. As in combustion, two distinct reaction regions are revealed under pyrolysis for all samples. The first region indicates distillation and the second one is due to thermal cracking reactions occur at high temperatures and completed up to 840 K. As expected, lighter crude oils have relatively higher amounts of mass loss in distillation region as compared to heavier ones. Besides, residue amount and burn-out temperatures are higher for heavier oils with higher asphaltene content in cracking region. DSC curves for both reactions show endothermic effects. In combustion and pyrolysis experiments, it is noticed that higher heating rates are resulted in higher reaction regions. Distinguishing peaks of samples shift to higher temperatures with an increase in heating rate. Heat of reaction amount under DSC curves is related to asphaltene content and &
#730
API gravity of crude oils. It is deduced that, when &
#730
API gravity of crude oils decreases, the heat value of this reaction increases. The kinetic parameters are evaluated by different kinetic models and mean activation energies (Em) of samples are obtained. At the end, a correlation is established between Em and &
#730
API gravity of oil samples. It is concluded that heavier oils have higher activation energy and Arrhenius constant values for each reaction region. Besides, it is proved that the activation energy is mostly insensitive to the heating rate.
16
Wright, Anthony D. "Publications submitted to the University of Nottingham for the degree of DSc". Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546239.
Testo completo
17
Webber, Glenda Vanessa. "The origin of multiple DSC melting peaks of Fischer-Tropsch hard waxes". Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/11668.
Testo completoAbstract (sommario):
Includes abstract.Includes bibliographical references (leaves 157-163).
The differential scanning calorimetry (DSC) analyses of the Fischer-Tropsch (FT) hard waxes display multiple melting peaks, the origin of which is unknown. The phenomenon is sometimes referred to in the literature, but no attempt has been made to explain its cause. There are a few known causes of melting bimodality in n-alkanes and their mixtures, petroleum waxes and polymers. These are: polymorphism, chain folding and bimodal molecular weight distributions
18
Silva, Teodora Cristina Pires Ferreira Leal da. "Aplicação de calorimetria diferencial de varrimento (DSC) na caracterização de fibras sintéticas". Master's thesis, Universidade de Évora, 2013. http://hdl.handle.net/10174/9725.
Testo completoAbstract (sommario):
Resumo:
Pretendeu-se com este trabalho aplicar a técnica analítica de
Calorimetria Diferencial de Varrimento (DSC) na caracterização de fibras
sintéticas. Apesar de o trabalho ser focalizado em fibras acrílicas e derivados,
foram estudados outros tipos de fibras, sintéticas e naturais. Este estudo foi
complementado com análises em Espectroscopia de Infravermelho (FTIR).
Verificou-se que se conseguiu distinguir as fibras de naturezas diferentes e
nalguns casos entre fibras acrílicas de origens diferentes.
Foi também desenvolvida uma técnica analítica baseada em DSC com o
objectivo de monitorizar o grau de oxidação/estabilização de fibras acrílicas
precursoras na primeira etapa do seu processo de conversão térmica em fibras
de carbono. Esta foi complementada com análises de densidade e às suas
propriedades mecânicas, bem como com ensaios de Índice de Oxigénio
Limitante (LOI).
Verificou-se que, com a extensão da oxidação, aumenta a densidade,
alongamento e a aromatização da fibra oxidada, diminuindo o calor libertado; Abstract:
“Application of Differential Scanning Calorimetry (DSC) for the
Characterization of Synthetic Fibers”
The purpose of this work was to apply the analytical technique of
Differential Scanning Calorimetry (DSC) for the characterization of synthetic
fibers. Although the work is focused on acrylic fibers and derivatives, other
types of synthetic fibers and some fibers of natural origin were also studied.
This study was complemented with analysis by infrared spectroscopy. It was
found that it was possible to distinguish between fibers of different nature and in
some cases from acrylic fibers of different origins.
An analytical technique based on DSC was also developed for the
purpose of monitoring the degree of oxidation / stabilization of acrylic fiber
precursors in the first step of the process of thermal conversion to carbon fibers.
This was complemented with analysis of the mechanical properties of the fibers
and testing of Limiting Oxygen Index.
It was found that, with the extent of oxidation the density, elongation and
aromatization of the oxidized fiber increased, reducing the heat release.
19
Shao, Changming 1959. "Implementation of DSC model for dynamic analysis of soil-structure interaction problems". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282628.
Testo completoAbstract (sommario):
The Disturbed State Concepts (DSC) model, with simplified unloading/reloading formulation, is implemented in a nonlinear dynamic finite element program for porous media named DSC-DYN2D. It can perform static, two phase dynamic and consolidation analysis of soils and soil-structure interaction problems with the DSC model. The model and the computer procedure are verified by back predictions of laboratory tests of clay, steel-clay interfaces as well as a simulation of pile-soil interaction problem. The Disturbed State Concepts have been developed recently as a constitutive modeling approach. In the DSC, the material is assumed to transform continuously and randomly from the relatively intact state to the fully adjusted state under loading. Hence, the observed response of the material is expressed in terms of the response of relatively intact and fully adjusted states. In this dissertation, the Disturbed State Concept constitutive model is developed by using the HiSS model for the relative intact part and the critical state model for the fully adjusted part in the material. The general formulation for implementation is developed. New and simplified unloading/reloading schemes are proposed for cyclic loading. Then the DSC model with the unloading/reloading scheme are implemented in the dynamic finite element program based on the generalized Biot's theory. The procedure for determining the parameters of the DSC model and the unloading/reloading is discussed. The parameters for the steel-clay interface are found from the tests and used for the prediction of the tests. Consolidation and cyclic loading tests from the field load tests on a pile segment were numerically simulated using the finite element program DSC-DYN2D and compared with field measurements and those from the previous analysis with the HiSS model. The DSC predictions show improved agreement with the field behavior of the pile compared to those from the HiSS model. The unloading/reloading models proposed in the study are simple yet give the realistic prediction of unloading and reloading behavior of the geomaterials under cyclic loading. Overall, the computer procedure with the DSC allows improved and realistic simulation of the complex dynamic soil-structure interaction problems.
20
Mahlin, Denny. "Phase Transformations in Solid Pharmaceutical Materials Studied by AFM, ESCA, DSC and SAXS". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4575.
Testo completo
21
Byakova, A. V., V. V. Cherednichenko, A. A. Scheretskiy, A. A. Vlasov e A. I. Yurkova. "Structural Evolution and Phase Transformation in Nanoquasicrystalline Al-Fe-Cr Alloy: DSC Analysis". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34854.
Testo completoAbstract (sommario):
Kinetic parameters for microstructural evolution and phase transformation in water atomized Al-Fe-Cr
based alloy with nominal composition Al94Fe3Cr3 have been examined by means of developed precise method
of DSC technique and confirmed by the results of XRD analysis. Two exothermic reactions including that
with a maximum at 380 – 400 degrees Celsius has been ascribed to dislocation reorganisation and recrystallisation process within the Al matrix although the main exothermic reaction with a maximum around 540 degrees Celsius arose
from decomposition of icosahedral quasicrystalline particles and simultaneous formation of the metastable
Al6Fe phase and more stable crystalline particles compositionally corresponded to the O-Al13Cr2 and
O-Al13Fe4 phases. Activation energy for the main exothermic reaction has been found to be roughly
about 53.1 kJ mol-1 which is significantly smaller than that for the bulk diffusion of either iron or chromium atoms in aluminium and very close to that for the vacancy migration.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34854
22
Nunes, Ronaldo Spezia. "Estudo do comportamento térmico de alguns aditivos alimentares por TG/DTG, DTA e DSC". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-25082009-161837/.
Testo completoAbstract (sommario):
Estudos termoanalíticos de alguns aditivos alimentares da classe dos realçadores de sabor foram desenvolvidos visando avaliar sua estabilidade e resistência durante o preparo de alimentos a quente assim como investigar os eventuais intermediários de decomposição que poderiam resultar destes processos. Os sais foram obtidos de fontes industriais ou sintetizados e submetidos à caracterização por análise elementar, espectrometria vibracional na região do infra-vermelho, termogravimetria/termogravimetria derivada, análise térmica diferencial e em alguns casos, calorimetria exploratória diferencial. Foram estudados o ácido glutâmico e seus sais de amônio, lítio e sódio mono e dissubstituídos. Em todos os casos observou-se uma conversão a piroglutamato após desidratação dos sais monossubstituídos, a qual ocorre via a a-carboxila. A estabilidade térmica destes sais foi da ordem de 190-200 °C. No caso dos sais dissubstituídos de lítio e sódio não houve conversão ao piroglutamato pois as duas carboxilas estão salificadas. Os glutamatos de magnésio, cálcio estrôncio e bário, também foram preparados e investigados quanto ao seu comportamento térmico. Os sais se formaram na estequiometria 2:1 (ligante:metal), apresentando águas de hidratação em número característico e foram estáveis até 190- 200 °C. Finalmente foram estudados os mecanismos de decomposição térmica do inosinato-monofosfato de sódio e do guanilato-monofosfato de sódio, dois nucleotídeos que apresentam a propriedade de realçar o sabor de alimentos. Ambos apresentaram elevado grau de hidratação, para o qual foi possível distinguir mecanismos característicos de desidratação. A decomposição dos sais anidros ocorreu com saída do grupo purínico, seguida da decomposição do restante da molécula e formação de pirofosfato de sódio como resíduo final.Thermal analytical studies of some food addictives of the flavor enhancer class were developed in order to evaluate their stability and resistance to the hot cooking process, as well as to identify the intermediaries of thermal decomposition that could remain at the end of such processes. The salts were obtained from industrial sources or synthesized and characterized by elemental analysis, infra-red spectroscopy, thermogravimetry/derivative thermogravimetry, differential thermal analysis and in some opportunities to differential scanning calorimetry. The glutamic acid and its ammonium, lithium and sodium salts mono and disubstituted were investigated. In all cases a conversion to pyroglutamate has been observed in the free acid and its monosubstituted salts after dehydration. The conversion undergoes by the ?-carboxyl group. The thermal stability was observed to be as high as 190-200 °C. In the case of the lithiu m and sodium dissubstituted salts any conversions to pyroglutamates were observed, once both carboxyl groups were salified. Magnesium, calcium, strontium and barium glutamates has also been synthesized and investigated in relation to its thermal behavior. The salts were formed in the 2:1 stoichiometry (ligand:metal), presenting hydration waters in a characteristic content and showed to be stable up to 190-200 °C. Finally the thermal decomposition mechanisms of dissodium inosinatemonophosphate and dissodium guanilate-monophosphate two nucleotides with flavor enhancement properties in food were also investigated. Both presented high degree of hydration, to which it was possible to propose a water release mechanism. The decomposition of the anhydrous salts occurred with release of the purine group followed by the decomposition of the rest of the molecule generating sodium pyrophosphate as residue.
23
Zhang, Mingqian. "Characterization of commercial linear low-density polyethylenes by TREF, SEC, DSC, and cross-fractionation". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/MQ47123.pdf.
Testo completo
24
Nassu, Renata Tieko. "Estudo do comportamento termico de oleos e gorduras por calorimetria de varredura diferencial : (DSC)". [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254674.
Testo completoAbstract (sommario):
Orientador : Lireny Ap. Guaraldo GonçalvesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-07-19T02:10:23Z (GMT). No. of bitstreams: 1 Nassu_RenataTieko_M.pdf: 2805995 bytes, checksum: 76b34503b54584b01cbb169963479f3d (MD5) Previous issue date: 1994
Resumo: A Calorimetria de Varredura Diferencial (Differentia! Scanning Calorimetry- DSC) vem sendo uma das técnicas mais utilizadas em análise térmica nas últimas décadas. O presente trabalho utiliza o DSC no estudo do comportamento térmico de óleos e gorduras. Analisou-se 14 amostras de óieos e gorduras refinados ou modificados por processos como hidrogenação, fracíonamento e interesterificação, de diferentes origens vegetais (soja, algodão, palma, babassu e palmiste). Determinou-se através das curvas de fusão e cristalização obtidos por DSC, parâmetros como temperaturas (ponto final de fusão e inicial de cristalização, picomáximo e 'bnset') e entalpias de mudança de fase, encontrando-se vaiores e perfiscaracterísticos para cada amostra, de acordo com sua composição de ácidos graxos. Foramencontrados os seguintes vaiores de entaípía de fusão em gorduras refinadas: 47,40; 24,61;79!02;90,57 e 92,94 J/g para os óleos de soja, algodão, palma, babassu e palmiste respectivamente e entalpías de cristalização de -l,81;-19,33;-52,92;-90,88 e -85,01 J/g para amesma ordem de amostras. Os óleos de soja e de aigodão refinados apresentaram os menoresvaiores de temperatura e entalpia, enquanto que os valores máximos para os mesmos parâmetros foram obtidos para a amostra de óleo de palma hidrogenado. Observou-se que ascurvas de DSC são influenciadas de forma significativa por fatores como amostragem, velocidade de aquecimento/resfriamento e temperagem da amostra. Valores de conteúdo de sólidos foram determinados através do cálculo de áreas parciais de curvas de fusão de DSC e comparados com aqueles obtidos pelo método do RMN pulsante, encontrando-se geralmente valores maiores para a técnica do DSC, sendo este fato atribuído a diversos fatores inerentes às amostras e às diferenças entre as próprias técnicas. O DSC demonstrou ser uma técnica rápida para determinação de vários parâmetros , tais como conteúdo de sólidos para óleos e gorduras, temperaturas e entalpias de transição de fase, além de fornecer curvas características de cada amostra
Abstract: Differential Scanning Calorimetry (DSC) has been one of the most popular thermal analysis techniques during the last two decades. The present work shows the utilization of DSC on investigation of the thermal behaviour of oils and fats. 14 samples of refined, hydrogenated, fractioned or interesterified fats of different origins (soybean, cottonseed, palm, babassu and palm kernel) were analyzed. Phase transition, peak and onset temperatures andenthalpies were obtained from DSC heating and cooling curves. Characteristic values andcurves were found for each sample according to its fatty acid composition. Those following fusion enthalpies were found for refined fats: 47.40; 24.61; 79.02; 90.5 and 92.94 J/g (soybean oil, cottonseed oil, palm oil, babassu oil and palm kerne! oil in this order) and -1.81;-19.33; ~52.92;-90.88 and -85.01 J/g crystallization enthalpies at the same order of samples. Refined soybean and cottonseed oils showed the lowest temperatures and enthalpies values while the highest values were obtained for hydrogenated palm oil. It was observed that sampling, scanning rate and sample tempering modified the shape of DSC curves. Solid fat content values were calculated through the partial areas of DSC heating curves. In a comparison with pulse NMR values, DSC values were generally higher than the pNMR ones. Differences between samples and the techniques themselves seems to be responsible for this fact. DSC was shown as a fast technique on solid fat content, characteristic temperatures and phase transitions enthalpies determinations besides giving a characteristic curve of each sample
Mestrado
Mestre em Tecnologia de Alimentos
25
Braga, Carlos Isidoro. "Desenvolvimento de metodologia para análise de DSC em altas taxas de transferência de calor". Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=872.
Testo completoAbstract (sommario):
O presente trabalho tem como objetivo propor uma metodologia de análise térmica pelo uso de calorimetria exploratória diferencial (DSC) com altas razões de aquecimento (razões >36 C.min 1). Para isto, é estabelecida uma metodologia de calibração pelo uso de padrões metálicos de índio, estanho, chumbo e zinco, avaliando-se a linearidade e a simetria do forno de DSC. Diferentes massas de índio, na faixa de 0,570 a 20,9mg, são submetidas a diferentes razões de aquecimento (4 a 324 C.min 1) e os valores experimentais de temperaturas de fusão e de entalpia estão em concordância com a literatura. Os eventos térmicos fusão e cristalização do polipropileno e da poliamida 66 são também estudados, tanto pela metodologia convencional como pela de altas razões de aquecimento. Os resultados experimentais mostram que a metodologia proposta pelo uso de altas razões de aquecimento permite a caracterização de eventos térmicos termodinâmicos tradicionais, como temperatura e entalpia de fusão e cristalização, com maior sensibilidade, resolução, exatidão e em menores períodos de tempo, atendendo as especificações ASTM, com a vantagem de se utilizar equipamentos de DSC já disponíveis nos laboratórios.
26
Ghoshal, Sushanta [Verfasser]. "Study of polymer film formation and their characterization using NMR, XRD and DSC / Sushanta Ghoshal". Aachen : Shaker, 2012. http://d-nb.info/1069044709/34.
Testo completo
27
Laplante, Michelle. "An investigation of the interactions between organic contaminants and various humic acids by DSC analysis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0012/MQ35019.pdf.
Testo completo
28
SANTOS, SAMANTHA FONSECA DOS. "DSC, DMA, XPS, CONTACT ANGLE E AFM ANALYSIS OF DE ACC/PHAMCL THICK FILMS SURFACES". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7887@1.
Testo completoAbstract (sommario):
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONeste trabalho, foram estudadas filmes poliméricos densos formadas por acetato de celulose (AcC) e polihidroxialkanoato de cadeia média PHAmcl, com diferentes concentrações relativas de cada polímero. Os filmes de PHAmcl/DAC foram preparadas a partir de soluções poliméricas, diluídas em dimetil cetona, na qual se realiza uma mistura com agitação contínua. Foram preparadas as amostras: AcC puro, PHAmcl puro e seis misturas com concentrações variando de 2 porcento a 12 porcento (m/v) de PHAmcl em AcC. Medidas de calorimetria diferencial exploratória e análise dinâmica mecânica foram realizadas a fim de se conhecer a miscibilidade das blendas formadas A composição química das superfícies desses filmes foi caracterizada utilizando a técnica de espectroscopia de fotoelétrons induzida por raios-X (XPS). A morfologia e as propriedades mecânicas das amostras foram estudadas com o auxílio da microscopia de força atômica (AFM). Observou-se nas misturas um enriquecimento na superfície de PHAmcl e uma alteração da morfologia para toda a superfície com a incorporação de PHAmcl. Foi observada uma diminuição na dureza com o aumento a concentração de PHAmcl no filmes. Os filmes apresentaram miscibilidade até 10 porcento PHAmcl/90porcentoAcC em volume.
In this work, the study of thick films formed by cellulose acetate and medium chain length polyhydroxyalkanotes with different molar concentration of PHB is presented. The films were prepared by polymeric solutions diluted in dimethil ketone with continued agitation. The solvent evaporation occurs on a glass plate in controlled atmosphere of 300 C. Eight samples were prepared: pure AcC and PHAmcl and mixtures with PHAmcl bulk concentrations in the range of 2 to 12 percent (w/v). Differential scanning calorimetry and dynamic mechanical analysis measurements were performed in order to know the samples miscibility. The surface chemical composition of the samples was characterized by X- ray photoelectron spectroscopy (XPS). The morphology and mechanical properties were studied by atomic force microscopy (AFM). PHAmcl surface enrichment and morphology modification of the films were observed on the whole surface with the increasing of PHAmcl. A decrease in the films hardness was observed for increasing PHAmcl bulk concentration. The films were found to be miscible until 10percentPHAmcl/90percentAcC bulk concentration.
29
Trindade, Nuno Miguel Passarinho. "Stochastic modeling of the thermal and catalytic degradation of polyethylene using simultaneous DSC/TG analysis". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8468.
Testo completoAbstract (sommario):
Dissertação para obtenção do Grau de Mestre em
Engenharia Química e BioquímicaIn the present work a stochastic model to be used for analyzing and predicting experimental data from simultaneous thermogravimetric (TG) and differential scanning calorimetry (DSC) experiments on the thermal and catalytic degradation of high-density polyethylene (HDPE) was developed. Unlike the deterministic models, already developed, with this one it’s possible to compute the mass and energy curves measured by simultaneous TG/DSC assays, as well as to predict the product distribution resulting from primary cracking of the polymer, without using any experimental information. For the stochastic model to predict the mass change as well as the energy involved in the whole process of HDPE pyrolysis, a reliable model for the cracking reaction and a set of vaporization laws suitable to compute the vaporization rates are needed. In order to understand the vaporization process, this was investigated separately from cracking. For that, a set of results from TG/DSC experiments using species that vaporize well before they crack was used to obtain a global correlation between the kinetic parameters for vaporization and the number of C-C bonds in the hydrocarbon chain. The best fitting curves were chosen based on the model ability to superimpose the experimental rates and produce consistent results for heavier hydrocarbons. The model correlations were implemented in the program’s code and allowed the prediction of the vaporization rates. For the determination of the global kinetic parameters of the degradation reaction to use in the stochastic model, a study on how these parameters influence the TG/DSC curves progress was performed varying those parameters in several simulations, comparing them with experimental data from thermal and catalytic (ZSM-5 zeolite) degradation of HDPE and choosing the best fitting. For additional improvements in the DSC stochastic model simulated curves, the thermodynamic parameters were also fitted. Additional molecular simulation studies based on quantum models were performed for a deeper understanding on the reaction mechanism and progress. The prediction of the products distribution was not the main object of the investigation in this work although preliminary results have been obtained which reveal some discrepancies in relation to the experimental data. Therefore, in future investigations, an improvement of this aspect is necessary to have a stochastic model which predicts the whole information needed to characterize HDPE degradation reaction.
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Mahfouz, Tarek Said. "Construction legal support for differing site conditions (DSC) through statistical modeling and machine learning (ML)". [Ames, Iowa : Iowa State University], 2009.
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Cai, Liuchun. "Molecular structure of (Ga₂S₃)x(GeS₂)₁₋x glasses raman scattering and T-modulated DSC". Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1057759838.
Testo completo
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Alves, Ricardo. "Estudo termoanalítico e de compatibilidade fármaco-excipiente de rifampicina e alguns medicamentos utilizados na terapêutica da tuberculose". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-31032008-162730/.
Testo completoAbstract (sommario):
Este trabalho teve por objetivo aplicar a análise térmica e outras técnicas físico-químicas e analíticas ao desenvolvimento e controle de qualidade de fármacos e medicamentos para tratamento de tuberculose, em especial a rifampicina. A calorimetria exploratória diferencial (DSC), termogravimetria/termogravimetria derivada (TG/DTG), análise elementar, espectrometria de absorção na região do infravermelho (IV) e difratometria de raios X (DRX) foram as principais ferramentas utilizadas. Estas técnicas permitiram: avaliar a estabilidade térmica e o processo de decomposição térmica da rifampicina e dos excipientes, utilizados em formulações farmacêuticas; diferenciar os dois tipos de formas polimórficas; desenvolver estudos para determinação de parâmetros cinéticos e avaliar as possíveis interações entre a rifampicina e excipientes. Os estudos foram desenvolvidos empregando duas amostras de rifampicina, identificadas como polimorfos I e II. Os resultados de análise elementar evidenciaram que ambas as amostras têm a mesma composição e estequiometria (C43H58N4O12), característica do fármaco em questão. Os espectros no IV de ambas as amostras são muito similares, porém apresentam ligeiras diferenças devido às pequenas variações que existem na conformação molecular das formas polimórficas. Essas diferenças são nítidas quando se compara as bandas de absorção dos grupos ansa-OH, furanona e acetil, em ambos os espectros. Os difratogramas de raios X evidenciam que ambas as amostras são cristalinas, porém as distâncias interplanares não são coincidentes confirmando que se trata de duas estruturas distintas. As curvas TG/DTG evidenciaram que o polimorfo I é mais estável termicamente que o polimorfo II. As curvas DSC confirmam o resultado de TG/DTG e permitem diferenciar claramente uma forma polimórfica da outra. A curva DSC do polimorfo II mostra que inicialmente ocorre o processo de fusão seguido de cristalização com a formação do polimorfo I, que simultaneamente se decompõe termicamente. O espectro infravermelho do produto isolado após a recristalização do polimorfo II confirma a conversão ao polimorfo I. A partir dos estudos cinéticos não isotérmicos e isotérmicos por TG foi possível calcular a energia de ativação envolvida na decomposição térmica de cada um dos polimorfos. Os estudos de pré-formulação, empregando misturas físicas na proporção 1:1 fármaco/excipiente, indicaram que há interação entre o polimorfo II e os excipientes PEG 6000 e Lutrol F68. Durante a fusão dos excipientes ocorre à dissolução do fármaco e a conseqüente conversão ao polimorfo I. Os estudos de compatibilidade fármaco-fármaco de rifampicina e isoniazida mostraram que há interação com ambos os polimorfos. Tudo indica que a interação entre as espécies conduz a formação do composto 3-(isonicotinoilhidrazinometil)rifamicina. A avaliação dos perfis termoanalíticos dos produtos comerciais permitiu identificar qual dos polimorfos foi empregado na produção. Foi possível concluir que os ensaios de DSC permitem identificar o tipo de polimorfo de rifampicina utilizado em associações com isoniazida.This work was aimed at implementing the thermal analysis and other physico-chemical and analytical techniques in the development and quality control of drugs and medicines for the treatment of tuberculosis, especially rifampicin. The differential scanning calorimetry (DSC), thermogravimetry/derivative thermogravimetry(TG/DTG), elemental analysis, X-ray diffraction (XRD) and infrared spectrometry (IR) were the main tools used. These techniques allowed to: evaluate thermal stability and the process of thermal decomposition of rifampicin and excipients used in pharmaceutical formulations; distinguish the two types of polymorphic forms; develop studies to establish kinetic parameters and evaluate the possible interactions between rifampicin and excipients. The studies were developed using two rifampicin samples, identified as polymorphs I and II. The elemental analysis results showed that both samples have the same composition and stoichiometry (C43H58N4O12), characteristic of the drug in question. IR spectra of both samples are very similar, but with little differences due to variations in the molecular conformation of polymorphic forms. These differences are clear when the absorption bands of ansa-OH, furanone and acetyl groups are compared in both spectra. XRD patterns showed that the two samples are crystalline and that they are two distinct structures. TG/DTG curves showed that polymorph I is more thermally stable than polymorph II. DSC curves confirm the TG/DTG results and allow to clearly differentiate a polymorphic form of the other. DSC curve of the polymorph II shows that initially occur the melting process, followed by crystallization and formation of polymorph I, which then is thermally decomposed. IR spectrum of the product isolated after recrystallization of polymorph II confirms the conversion to polymorph I. After Isothermal and non-isothermal kinetic studies by TG, it was possible to calculate, in both cases, the activation energy envolved in the thermal decomposition of each polymorph. The pre-formulation studies, using physical mixtures in the proportion 1:1 drug/excipient, indicated that there is interaction between the polymorph II and PEG 6000 and Lutrol F68. The excipients melt and dissolve the drug, which is converted to polymorph I. The drug-drug compatibility studies of rifampicin and isoniazid showed that there is interaction with both polymorphs. It appears that the interaction between the species leads to formation of the 3-(isonicotinylhydrazinmethyl) rifamycin compound. The evaluation of thermoanalytical profiles of commercial products allowed the identification of the polymorph was used in the formulation. It was possible to conclude that DSC tests identify the rifampicin polymorph used in association with isoniazid.
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Perpetuo, Glauco Lini. "Estudo termoanalítico e caracterização no estado sólido da interação química entre cetoprofeno e alguns compostos orgânicos". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-09032016-135907/.
Testo completoAbstract (sommario):
Neste trabalho, foi realizado o estudo termoanalítico e a caracterização no estado sólido da interação química entre o cetoprofeno (CET) e alguns compostos orgânicos (benzamida (BA), picolinamida (PA), nicotinamida (NA), isonicotinamida (INA), pirazinamida (PZA), ácido salícílico (SA) e ácido benzoico (BA)), visando a obtenção de cocristais. A mecanoquímica foi utilizada como método de preparação dos compostos sólidos, e os mesmos foram analisados por calorimetria exploratória diferencial (DSC), espectroscopia de infravermelho com transformadas de Fourier (FTIR), e difração de raios X de pó (XRPD). A escolha dos compostostos orgânicos (co-formadores) foi baseada em suas estruturas moleculares, de modo que aqueles selecionados para esse trabalho possuíssem uma estrutura molecular capaz de possibilitar a formação de síntons moleculares adequados à formação dos cocristais desejados. A análise dos resultados obtidos permitiu verificar que, nas condições experimentais utilizadas, todas as misturas estudadas formaram apenas compostos eutéticos. Entretanto, embora os diagramas de fases e os experimentos de DSC, raios X e FTIR tenham confirmado apenas a obtenção de compostos eutéticos entre o cetoprofeno e os co-formadores estudados, o método do contato de Kofler indicou a formação de um cocristal entre o cetoprofeno e nicotinamida. Assim sendo, o trabalho realizado até agora abre portas para investigações futuras, nomeadamente, com relação aos estudos de termomicroscopia relativos aos demais sistemas estudados neste trabalho.In this work, we performed the thermoanalytical study and characterization at the solid state on the chemical interaction between ketoprofen (CET) and some organic compounds (benzamide (BA), picolinamide (PA), nicotinamide (NA), isonicotinamide (INA), pyrazinamide (PZA), salicylic acid (SA) and benzoic acid (BA)), aimed at obtaining cocrystals. The mechanochemical method was used for the preparation of solid compounds, and they were analyzed by differential scanning calorimetry (DSC), infrared spectroscopy with Fourier transform (FTIR), and X-ray powder difraction (XRPD). The choice of the organic compounds (co-formers) was based on their molecular structures, so that those selected for this work possess a molecular structure able to allow the formation of molecular synthons suitable for cocrystals formation. The analysis of the results has shown that under the experimental conditions used, all systems studied has formed only eutectic compounds. However, although the phase diagrams and DSC experiments, X-ray and FTIR have confirmed obtaining only eutectic compounds between ketoprofen and co-formers studied, the method of contact Kofler has indicated the discovery of a new co-crystal formed between ketoprofen and nicotinamide. Therefore, the work done so far opens the door to future research in particular with regard to thermomicroscopy studies related to other systems studied in this work.
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Fernandes, Roger Gomes. "Efeito do tamanho e forma das partículas na cinética de cristalização de pó de vidro de diopsídeo detectada por DSC". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-12042017-161520/.
Testo completoAbstract (sommario):
A variação da densidade de um compacto de partículas de vidro durante o aquecimento pode ser calculada aproximadamente pelo Modelo de Clusters de sinterização de vidros por escoamento viscoso com cristalização superficial concorrente. Nesse modelo, o efeito do formato das partículas é tratado como um fator de correção e determinado como um parâmetro de ajuste a dados experimentais. Portanto, um parâmetro de forma independente do modelo ainda deve ser considerado para que a cinética de sinterização de vidros possa ser precisamente calculada. A cinética de cristalização de vidros em pó também depende do formato das partículas e pode ser determinada através de Calorimetria Diferencial Exploratória (DSC). Assim, o objetivo desse trabalho foi acessar o formato de partículas de vidro através do estudo da cinética de cristalização das mesmas, visando posteriormente usar as informações de formato em cálculos cinéticos de sinterização. Para isso, o pico de cristalização de um compacto de diopsídio vítreo em pó foi determinado por DSC e avaliado em função do formato de partículas considerando diferentes morfologias regulares. A cinética de cristalização foi calculada considerando modelos distintos de cristalização de partículas de vidro com nucleação heterogênea na superfície. Os picos de cristalização foram determinados por DSC para um vidro de diopsídio (\'Ca\'\'O\'.\'Mg\'\'O\'.2\'Si\'\'O IND.2\') de composição próxima à estequiométrica, em amostras com diferentes granulometrias, e taxa de aquecimento de 10°C/min. As curvas experimentais foram comparadas com picos de cristalização calculados para pós de vidro de diopsídio com diferentes formatos regulares e granulometrias. A caracterização do formato das partículas iniciais e da microestrutura de compactos de vidros sinterizados não isotermicamente auxiliou na interpretação dos resultados. Os intervalos de temperatura onde ocorrem os picos de cristalização calculados coincidiram com os experimentais, mas o máximo dos picos variou em função da cinética de cristalização para diferentes formatos de partículas. Para o propósito do presente trabalho, observou-se um bom acordo, porém não perfeito, entre as curvas calculadas e experimentais, demostrando-se que DSC é uma técnica promissora para a caracterização de um fator de forma efetivo para o cálculo da cinética de sinterização de partículas de vidro com cristalização concorrente.The densification rate of glass particle compacts during a temperature rise can approximately be calculated from the so-called Clusters model of sintering with concurrent crystallization, in which the particle shape effect is treated as a correction factor and determined as a fitting parameter. Thus, a model-independent particle shape parameter still has to be considered so that glass sintering kinetics can be precisely calculated. Aiming to access the particle shape effect on the glass sintering kinetics with concurrent crystallization, the crystallization peak of a glass particle compact was determined by Differential Scanning Calorimetry (DSC) and evaluated as a function of particle shape, regarding distinct regular morphologies. The crystallization kinetics was calculated considering distinct models of glass particle phase transformation. Crystals were considered to nucleate heterogeneously on particles surface. The expected DSC crystallization peaks were calculated for glass particles with near-stoichiometric diopside composition (\'Ca\'\'O\'.\'Mg\'\'O\'.2\'Si\'\'O IND.2\') heated up at a constant rate (10°C/min), and compared with the crystallization peak experimentally obtained for diopside glass powders with irregular shape and different granulometries. The characterization of the initial particle shape and the microstructure of non-isothermally sintered glass compacts aided in the interpretation of the results. The calculated crystallization peaks stand in the same temperature range as the experimental one, although the peak maxima vary as a function of crystallization kinetics due to the different particle shapes. For the purposes of the present research, there was a clear agreement, yet not perfect, between the calculated curves and experimental data, showing that DSC is a promise technique to characterize an effective shape factor to assess the glass particle sinter-crystallization kinetics.
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Gul, Kiymet Gizem. "Thermal Characterization And Kinetic Analyis Of Sara Fractions Of Crude Oils By Tga And Dsc Methods". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613614/index.pdf.
Testo completoAbstract (sommario):
In this thesis, four different crude oil samples and their saturate, aromatic and resin fractions were analyzed by two different thermoanalytical methods, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The experiments were performed at three different heating rates (5, 10 and 15 °C/min) under air atmosphere. Same gas flow rate and same pressure were applied to all samples. The aim is to determine the kinetic analysis and combustion behavior of crude oils and their fractions and also determining the effect of heating rate on all samples. For all samples two main reaction regions were observed in thermogravimetry (TG), differential thermogravimetry (DTG) and DSC curves due to the oxidative degradation of crude oil components. It was deduced that the free moisture, volatile hydrocarbons were evaporated from the crude oils, light hydrocarbons were burned and fuel was formed in the first reaction region. The second reaction region was the main combustion region where the fuel was burned. From the TGA curves, it was detected that the heavier fraction, resins, lost considerable amounts of their initial mass, approximately 35%, while saturates lost only approximately 3% of their initial mass in the second reaction region. DSC curves of the samples were also examined and observed that as the sample got heavier, the heat of the reaction increased. Saturates, lightest part of the crude oil fractions, gave minimum heat of reaction. As the heating rate increased, shift of peak temperatures to high values and higher reaction regions were observed. The kinetic analysis of crude oils and their fractions were also performed using different kinetic methods. Activation energies (E), mean activation energies (Emean) and Arrhenius constants were found for crude oils and fractions. It was deduced that the resins gave the highest activation energy and Arrhenius constant for both reaction regions. Moreover, it was encountered that heating rate has no effect on activation energies.
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Wells, David F. "Experimental and computational study of the detection and stability of polymorphs using PXRD, DSC and solubility /". View online ; access limited to URI, 2008. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3314449.
Testo completo
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Mohanty, Chandi P. "Direct Evidence for Topological Phases in Sodium Phosphate Glasses from Raman Scattering, Infrared Reflectance and Modulated DSC". University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535377235070592.
Testo completo
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Hurtado, Centeno Alonso D. "Diseño de un sistema embebido para el monitoreo de señales electrocardiográficas". Bachelor's thesis, Universidad Ricardo Palma, 2012. http://cybertesis.urp.edu.pe/handle/urp/1226.
Testo completoAbstract (sommario):
El presente proyecto de tesis consiste en el diseño de un equipo biomédico, el electrocardiógrafo, que le permite al especialista de la salud ver la evolución de la señal eléctrica emitida por el corazón. Esta señal es adquirida mediante un sistema de acondicionamiento de señales y procesada por un controlador digital de señales, así como también los periféricos que muestra la información procesada. Paralelamente, se puede enviar esta información a una computadora, donde un programa se encargara de visualizar esta señal y almacenarla en una base de datos.
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Moncel, Matthieu. "Analyse thermique avancée pour l’étude et la caractérisation de produits pétroliers complexes tels que les bitumes". Thesis, Nice, 2014. http://www.theses.fr/2014NICE4147.
Testo completoAbstract (sommario):
Au cours de cette thèse, de nouvelles méthodes d’analyse thermique et de traitement des données applicables à l’étude et la caractérisation de produits pétroliers complexes, ont été proposées, afin de mieux caractériser les bitumes. Le bitume, sous-produit de l’industrie pétrolière, est un matériau complexe dont les propriétés et la composition changent au gré des cocktails de pétroles bruts ou des procédés de raffinage. Une connaissance approfondie des propriétés de chaque bitume est donc nécessaire. Les tests mécaniques normés utilisés aujourd’hui pour caractériser le bitume sont insuffisants. Afin de pallier ce problème les techniques de DSC avancées ont été exploitées. Ce travail a porté principalement sur l’étude des trois phénomènes pouvant être observés au cours du chauffage des bitumes: la transition vitreuse, la cristallisation et la fusion. La première partie de ce travail a été consacrée à l’étude de ces trois phénomènes sur des molécules modèles, la diéthanolamine et la triéthanolamine. L’intérêt de la perturbation stochastique de température (TOPEM®) réside notamment dans la possibilité de séparer certains phénomènes se produisant sur un même domaine de températures. La méthodologie développée a ensuite été appliquée aux bitumes afin de mettre en évidence des corrélations entre données DSC (fraction cristallisable, température de transition vitreuse, température et enthalpie de fusion) et données mécaniques. Il a été montré également que la calorimétrie ultra-rapide permet de séparer certains phénomènes grâce à une approche différente mais complémentaire à la perturbation stochastique de température TOPEM®This thesis tackled new methods of thermal analysis and data treatment applicable to the study and characterization of complex petroleum products. The objective was to better characterize bitumen, which, as a by-product of petroleum industry, is a complex material. Its properties and composition are not set and change according to the cocktails of crude oils or to the refining processes. Thorough knowledge of the properties of asphalt is thus necessary to be able to use them in the best conditions. The standardized mechanical tests used today to characterize the asphalt are insufficient. To compensate for this problem, the techniques of advanced DSC were exploited. This work concerned mainly the study of three phenomena which can be observed during the heating of asphalts: glass transition, crystallization, and melting. The first part of this work was dedicated to the study of these three phenomena on model molecules _ the diethanolamine and the triethanolamine _ as they were presenting thermal events in a range of temperatures similar to the one of bitumen. The interest of the stochastic temperature perturbation (TOPEM®) lies in particular in the possibility of separating some phenomena occurring on the same range of temperatures. Thus, thanks to this method, glass transition can be analyzed independently of the enthalpic relaxation or of the crystallization. The developed methodology was then applied to bitumen so as to highlight correlations between DSC data and mechanical data . It was also shown that the ultra-fast calorimetry enables to separate some phenomena thanks to a different but complementary approach of stochastic temperature perturbation TOPEM®
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Zernerová, Alena. "DSC analýza léčiv". Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-272164.
Testo completoAbstract (sommario):
A DSC calorimeter 200 Phox® was used for measurements of thermal behaviour of Tiaprofenic acid, Salicylic acid, Acetylsalicylic acid, Nimesulid, Phenacetine, Phenazone, Propyphenazone, Tribuzone, and Suppository mass Adeps neutralis.
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Bucharová, Veronika. "DSC studium lipidických systémů II". Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-324553.
Testo completoAbstract (sommario):
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Veronika Bucharová Supervisor: RNDr. Marie Musilová, CSc. Title of diploma thesis: DSC study of lipid systems II This work deals with the interaction of skin lipids and water. The epidermal lipids (especially ceramides and cholesterol) and water create together lamellar structure which is the essence of the skin barrier. To create a lipid layer we used a cholesterol and a synthetic pseudoceramide 14S24 (synthesized at the Department of Inorganic and Organic Chemistry, Faculty of Pharmacy in Hradec Králové). The ratio of these two components is chosen so that the cholesterol in the molten pseudoceramide dissolves and during cooling down doesn't separately crystallize. Samples of this mixture with water and without water were evaluated by using differential scanning calorimetry (DSC). The samples were in high-pressure sample crucibles repeatedly heated up above and below the melting point and congealing of the mixture. We watched the changes of calorimetric characteristic that may be indicative of interaction lipid mixtures with water. We find out that value of heat of melting for inserted water decreases after adding water to mixture of cholesterol and pseudoceramide. It shows on...
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Cheng, Yu-Ming, e 鄭幼民. "Technological Development Trend of DSC Industry". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/83619530657633135501.
Testo completoAbstract (sommario):
碩士國立交通大學
管理學院高階主管管理碩士學程
96
Digital Still Camera is one of the electronic products for general consumers. It integrates optics, photo-electricity, mechanics, electronic, and software technologies. After past years developing, the DSC industry becomes very mature and competitive. However, many key technologies such as CCD and optical lens are still controlled by Japanese venders. The whole marketing is also handled by Japanese venders. After past thirteen years developing, Taiwan becomes the OEM/ODM center for the whole worldwide DSC industry. To compete with others, almost all DSC venders in Taiwan invest more resources in perspective studying for marketing and technology. And hope to get more order from customers earlier. Most of venders forecast the technology trend by purchasing expensive and bad-availability survey report or by judging the unreliable information collected from market by them themselves. Actually, product specification is the easiest gotten document about product technology. We could get many useful information by analyzing the statistics of product specification. The topic of this thesis is to analyze some important specifications by applying technology forecasting for the past historical product specifications to understand the development trend of DSC technology in the future.
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Valentová, Markéta. "STUDIUM DEGRADACE POLYESTEROVÝCH NOSIČŮ LÉČIV METODOU DSC". Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-337410.
Testo completoAbstract (sommario):
Farmaceutická fakulta, Katedra farmaceutické technologie, Hradec Králové, 2014 Vypracovala: Markéta Valentová Školitel: Doc. RNDr. Milan Dittrich, CSc. ABSTRACT STUDY OF POLYESTER DRUG CARRIERS DEGRADATION USING THE DSC METHOD The aim of this work was focused on the study of relations among various parameters of degradation process, such as time-dependent range of glass transition temperature, swelling, erosion, and molar weight decrease. Two model polyesters of two type architectures of polyester molecules were used and monitored during two-week period. In the theoretical part of this diploma thesis are in details described biopolymers with stimulus responsive activity and exploitation of these materials in various biomedical applications in the topic of tissue engineering. The experimental part of this work is directed into the study of molecule degradation parameters, eventually into simulated biodegradation in the in vitro conditions of two different in the type polyesters with the contrast polyester molecule constitution. It was demonstrated that parameter Mn decreases towards the limit values. Between the values of molar weight and glass transition temperature is not Flory-Fox relation in the advanced phase of degradation process. The erosion of the material begins after the lag-time in the dependency...
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Lin, Chien-Chung, e 林建中. "A Generic DSC Software Framework in Handset Device". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/64075782270184318926.
Testo completoAbstract (sommario):
碩士國立交通大學
電機資訊學院碩士在職專班
93
In traditional DSC software in handset device development, developers can spend huge amounts of time developing DSC software in handset device. Based on this premise, we approach this problem by exploring a better method to develop DSC software in handset device easily. In this thesis, we research the basic requirement, design pattern and a program generation methodology to develop generic DSC software framework. Finally, we demonstrate the applicability of the proposed methodology by means of an example application.
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Yo, Jin-Min, e 尤勁旻. "Thermal Decompositions of Dialkyl Peroxides Studied by DSC". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40835864786414617120.
Testo completoAbstract (sommario):
碩士嘉南藥理大學
職業安全衛生系
104
Organic peroxides (ROO-R ') are commonly used in the polymer industry as an initiator for polymerization or a crosslinking agent for polymeric materials and are regarded as the derivatives of hydrogen peroxide (HOOH). Organic peroxide is characterized by the presence of a weak oxygen–oxygen bond (–O–O–) in the molecule resulting in easily decomposed, flammable, and exposable characteristics, making it very sensitive to heat, shock, friction, etc. During the manufacturing process or storage process, if some unexpected process deviation such as heat accumulated, heat or incompatible trace (such as acid, alkali, organic compound or metal ion) occurred, there will be a severe exothermic heat, resulting in decomposition and thermal runaway reactions. Incidents of fires or explosions caused by thermal decompositions of organic peroxides have occurred globally. Dialkyl peroxides (or di-tertiary alkyl) are among the most stable of all the commercially available organic peroxides. When subjected to heat, dialkyl peroxides decompose and generate a pair of alkoxyl radicals, which can initiate the desired reaction. Their stable alkoxy radicals have drawn lots of attention and have been studied by many researchers for their thermal kinetic decomposition behaviors. Although di-tertiary butyl peroxide (DTBP) is one of the most stable dialkyl peroxide and is also recognized as a standard reference material, it has caused a fire due to leakage. In Taiwan, dicumyl peroxide (DCPO) had caused a thermal runaway explosion of a reactor due to a mistaken addition of the catalyst in the manufacturing process. In this study, DSC and a thermal analysis software (For K) were used to study thermal hazards of four dialkyl peroxides (such as di-terbutyl peroxide (DTBP), di-amyl peroxide (DAPO), tertiary butyl cumyl peroxide (TBCP) and dicumyl peroxide (DCPO), etc.). DTBP was used as a standard reference sample in this study to investigate (i) The thermal decomposition mode of dialkyl peroxides (with DTBP as an example); (ii) The effect of heating rate on thermal kinetics of both DTBP and DCPO; (iii) The effect of different substituents on the thermal kinetics of the four dialkyl peroxides. The results show that thermal decomposition behavior of DTBP is a two-stage reaction (Stage: A → B1 → B); Increases in heating rate increases extrapolated onset temperature (Ts), the peak temperature (Tp), and only increases the onset temperature (To) by a little. However, increases in heating rate shows little or no effect on decomposition heat (ΔH), activation energy (Ea) and frequency factor (A) for both DTBP and DCPO. Dialkyl peroxides possessed an average eigenvalue of log A at about 14.3 ± 1.1. This is closely in agreement with log A = 14, which is a common pre-exponential factor for b C–C bond scission rate constant of all alkoxy radicals studied by Fittschen et al.. According to To, the ranking of thermal stability on dialkyl peroxides is determined to be in the following sequence: DCPO < DAPO < DTBP and DCPO < TBCP. Finally, the time to maximum rate (TMRad) of DTBP obtained from both For K and AKTS softwares are fairly close.
46
Gaspar, Daniela Filipa Barreira. "Caracterização de Materiais Cimentícios por TG e DSC". Master's thesis, 2017. http://hdl.handle.net/10362/101391.
Testo completo
47
Ferreira, Carlos Alberto Pereira. "Verilog implementation of the VESA DSC compression algorithm". Master's thesis, 2016. https://hdl.handle.net/10216/89000.
Testo completoAbstract (sommario):
O trabalho consiste em implementar em verilog o Standard de compressão VESA DSC v1.1. O projecto está na fase de teste e optimização para cumprir restrições de timming. É esperado estar concluido nos inicios de Junho. Feito isto será feita uma comparação entre uma abordagem usando ferramentes de síntese de alto nível e a abordagem "manual" (RTL)
48
Ferreira, Carlos Alberto Pereira. "Verilog implementation of the VESA DSC compression algorithm". Dissertação, 2016. https://hdl.handle.net/10216/89000.
Testo completoAbstract (sommario):
O trabalho consiste em implementar em verilog o Standard de compressão VESA DSC v1.1. O projecto está na fase de teste e optimização para cumprir restrições de timming. É esperado estar concluido nos inicios de Junho. Feito isto será feita uma comparação entre uma abordagem usando ferramentes de síntese de alto nível e a abordagem "manual" (RTL)
49
Maršálková, Lucie. "Využití DSC ke stanovení obsahové stejnoměrnosti metronidazolu v čípcích". Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-272195.
Testo completoAbstract (sommario):
The aim of this work is the evaluation of extemporaneously prepared metronidazole-containing suppositories. Content uniformity, dispersion of the active ingredient, and the content in relation to the declared one was examined. The content of the active ingredient was determined by means of DSC. The preparations complied with the test of content uniformity. The content of the active ingredient was lower that the declared one.
50
Yang, Su Wei, e 楊世瑋. "Investigating poly(dimethyl siloxane) membrane and solvents interactions using DSC". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/20233266426115027618.
Testo completoAbstract (sommario):
碩士長庚大學
化工與材料工程研究所
92
The objective of this study was to investigating poly(dimethyl siloxane) membrane and organic solvents interaction using low temperature differential scanning calorimetry(DSC). The organic solvents used include water, cyclohexane, benzene, toluene and m-xylene. The diffusion coeifficients of organic solvents of free state and bound state were calculated vapor and solvent sorption kinetics through gravimetic method. The enthalpy values of solvents and PDMS membranes were determined and the solvent contents of free state were measured by comparing their enthalpy with pure solvent. The maxumim bound amount of solvent in PDMS was in the order cyclohexane > m-xylene > toluene > benzene, as in the reverse of difference in the solubility parameter between solvents and PDMS. Therefore it indicated that solvent content in PDMS was related to its solubility parameter. Its was found that diffusion coeifficient of the free state solvent was one magnitude higher than that in the bound state and the diffusivity was in the order toluene > cyclohexane > benzene > m-xylene. The solvent diffusivity in PDMS depended on the solvent nature, solubility and the penetrant state.