Teses / dissertações: "Physical and chemical characterizations"

1

Kavanagh, Debbie M. "Chemical and physical characterization of clay bodies". Thesis, Aston University, 2001. http://publications.aston.ac.uk/9643/.

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Suitable methods for the assessment of the effect of freeze-thaw action upon ceramic tiles have been determined. The results obtained have been shown to be reproducible with some work in this area still warranted. The analysis of Whichford Potteries clays via a variety of analytical techniques has shown them to be a complex mix of both clay and non-clay minerals. 57Fe Mössbauer spectroscopy has highlighted the presence of both small and large particleα-Fe203, removable via acid washing. 19F MAS NMR has demonstrated that the raw Whichford Pottery clays examined have negligible fluorine content. This is unlikely to be detrimental to ceramic wares during the heating process. A unique technique was used for the identification of fluorine in solid-state systems. The exchange of various cations into Wyoming Bentonite clay by microwave methodology did not show the appearance of five co-ordinate aluminium when examined by 27Al MAS NMR. The appearance of Qo silicate was linked to an increase in the amount of tetrahedrally bound aluminium in the silicate framework. This is formed as a result of the heating process. The analysis of two Chinese clays and two Chinese clay raw materials has highlighted a possible link between the two. These have also been shown to be a mix of both clay and non-clay minerals. Layered double hydroxides formed by conventional and microwave methods exhibited interesting characteristics. The main differences between the samples examined were not found to be solely attributable to the differences between microwave and conventional methods but more attributable to different experimental conditions used.

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2

Fracasso, Guido <1960&gt. "Synthesis and Physical-Chemical characterization of Metallic Nanoparticles". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2895/2/Fracasso_Guido_tesi.pdf.

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The stabilization of nanoparticles against their irreversible particle aggregation and oxidation reactions. is a requirement for further advancement in nanoparticle science and technology. For this reason the research aim on this topic focuses on the synthesis of various metal nanoparticles protected with monolayers containing different reactive head groups and functional tail groups. In this work cuprous bromide nanocrystals haave been synthetized with a diameter of about 20 nanometers according to a new sybthetic method adding dropwise ascorbic acid to a water solution of lithium bromide and cupric chloride under continuous stirring and nitrogen flux. Butane thiolate Cu protected nanoparticles have been synthetized according to three different syntesys methods. Their morphologies appear related to the physicochemical conditions during the synthesis and to the dispersing medium used to prepare the sample. Synthesis method II allows to obtain stable nanoparticles of 1-2 nm in size both isolated and forming clusters. Nanoparticle cluster formation was enhanced as water was used as dispersing medium probably due to the idrophobic nature of the butanethiolate layers coating the nanoparticle surface. Synthesis methods I and III lead to large unstable spherical nanoparticles with size ranging between 20 to 50 nm. These nanoparticles appeared in the TEM micrograph with the same morphology independently on the dispersing medium used in the sample preparation. The stability and dimensions of the copper nanoparticles appear inversely related. Using the same methods above described for the butanethiolate protected copper nanoparticles 4-methylbenzenethiol protected copper nanoparticles have been prepared. Diffractometric and spectroscopic data reveal that decomposition processes didn’t occur in both the 4-methylbenzenethiol copper protected nanoparticles precipitates from formic acid and from water in a period of time six month long. Se anticarcinogenic effects by multiple mechanisms have been extensively investigated and documented and Se is defined a genuine nutritional cancer-protecting element and a significant protective effect of Se against major forms of cancer. Furthermore phloroglucinol was found to possess cytoprotective effects against oxidative stress, thanks to reactive oxygen species (ROS) which are associated with cells and tissue damages and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. The goal of our work has been to set up a new method to synthesize in mild conditions amorphous Se nanopaticles surface capped with phloroglucinol, which is used during synthesis as reducing agent to obtain stable Se nanoparticles in ethanol, performing the synergies offered by the specific anticarcinogenic properties of Se and the antioxiding ones of phloroalucinol. We have synthesized selenium nanoparticles protected by phenolic molecules chemically bonded to their surface. The phenol molecules coating the nanoparticles surfaces form low ordered arrays as can be seen from the wider shape of the absorptions in the FT-IR spectrum with respect to those appearing in that of crystalline phenol. On the other hand, metallic nanoparticles with unique optical properties, facile surface chemistry and appropriate size scale are generating much enthusiasm in nanomedicine. In fact Au nanoparticles has immense potential for both cancer diagnosis and therapy. Especially Au nanoparticles efficiently convert the strongly adsorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. According to the about, metal nanoparticles-HA nanocrystals composites should have tremendous potential in novel methods for therapy of cancer. 11 mercaptoundecanoic surface protected Au4Ag1 nanoparticles adsorbed on nanometric apathyte crystals we have successfully prepared like an anticancer nanoparticles deliver system utilizing biomimetic hydroxyapatyte nanocrystals as deliver agents. Furthermore natural chrysotile, formed by densely packed bundles of multiwalled hollow nanotubes, is a mineral very suitable for nanowires preparation when their inner nanometer-sized cavity is filled with a proper material. Bundles of chrysotile nanotubes can then behave as host systems, where their large interchannel separation is actually expected to prevent the interaction between individual guest metallic nanoparticles and act as a confining barrier. Chrysotile nanotubes have been filled with molten metals such as Hg, Pb, Sn, semimetals, Bi, Te, Se, and with semiconductor materials such as InSb, CdSe, GaAs, and InP using both high-pressure techniques and metal-organic chemical vapor deposition. Under hydrothermal conditions chrysotile nanocrystals have been synthesized as a single phase and can be utilized as a very suitable for nanowires preparation filling their inner nanometer-sized cavity with metallic nanoparticles. In this research work we have synthesized and characterized Stoichiometric synthetic chrysotile nanotubes have been partially filled with bi and monometallic highly monodispersed nanoparticles with diameters ranging from 1,7 to 5,5 nm depending on the core composition (Au, Au4Ag1, Au1Ag4, Ag). In the case of 4 methylbenzenethiol protected silver nanoparticles, the filling was carried out by convection and capillarity effect at room temperature and pressure using a suitable organic solvent. We have obtained new interesting nanowires constituted of metallic nanoparticles filled in inorganic nanotubes with a inner cavity of 7 nm and an isolating wall with a thick ranging from 7 to 21 nm.

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3

Fracasso, Guido <1960&gt. "Synthesis and Physical-Chemical characterization of Metallic Nanoparticles". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2895/.

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The stabilization of nanoparticles against their irreversible particle aggregation and oxidation reactions. is a requirement for further advancement in nanoparticle science and technology. For this reason the research aim on this topic focuses on the synthesis of various metal nanoparticles protected with monolayers containing different reactive head groups and functional tail groups. In this work cuprous bromide nanocrystals haave been synthetized with a diameter of about 20 nanometers according to a new sybthetic method adding dropwise ascorbic acid to a water solution of lithium bromide and cupric chloride under continuous stirring and nitrogen flux. Butane thiolate Cu protected nanoparticles have been synthetized according to three different syntesys methods. Their morphologies appear related to the physicochemical conditions during the synthesis and to the dispersing medium used to prepare the sample. Synthesis method II allows to obtain stable nanoparticles of 1-2 nm in size both isolated and forming clusters. Nanoparticle cluster formation was enhanced as water was used as dispersing medium probably due to the idrophobic nature of the butanethiolate layers coating the nanoparticle surface. Synthesis methods I and III lead to large unstable spherical nanoparticles with size ranging between 20 to 50 nm. These nanoparticles appeared in the TEM micrograph with the same morphology independently on the dispersing medium used in the sample preparation. The stability and dimensions of the copper nanoparticles appear inversely related. Using the same methods above described for the butanethiolate protected copper nanoparticles 4-methylbenzenethiol protected copper nanoparticles have been prepared. Diffractometric and spectroscopic data reveal that decomposition processes didn’t occur in both the 4-methylbenzenethiol copper protected nanoparticles precipitates from formic acid and from water in a period of time six month long. Se anticarcinogenic effects by multiple mechanisms have been extensively investigated and documented and Se is defined a genuine nutritional cancer-protecting element and a significant protective effect of Se against major forms of cancer. Furthermore phloroglucinol was found to possess cytoprotective effects against oxidative stress, thanks to reactive oxygen species (ROS) which are associated with cells and tissue damages and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. The goal of our work has been to set up a new method to synthesize in mild conditions amorphous Se nanopaticles surface capped with phloroglucinol, which is used during synthesis as reducing agent to obtain stable Se nanoparticles in ethanol, performing the synergies offered by the specific anticarcinogenic properties of Se and the antioxiding ones of phloroalucinol. We have synthesized selenium nanoparticles protected by phenolic molecules chemically bonded to their surface. The phenol molecules coating the nanoparticles surfaces form low ordered arrays as can be seen from the wider shape of the absorptions in the FT-IR spectrum with respect to those appearing in that of crystalline phenol. On the other hand, metallic nanoparticles with unique optical properties, facile surface chemistry and appropriate size scale are generating much enthusiasm in nanomedicine. In fact Au nanoparticles has immense potential for both cancer diagnosis and therapy. Especially Au nanoparticles efficiently convert the strongly adsorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. According to the about, metal nanoparticles-HA nanocrystals composites should have tremendous potential in novel methods for therapy of cancer. 11 mercaptoundecanoic surface protected Au4Ag1 nanoparticles adsorbed on nanometric apathyte crystals we have successfully prepared like an anticancer nanoparticles deliver system utilizing biomimetic hydroxyapatyte nanocrystals as deliver agents. Furthermore natural chrysotile, formed by densely packed bundles of multiwalled hollow nanotubes, is a mineral very suitable for nanowires preparation when their inner nanometer-sized cavity is filled with a proper material. Bundles of chrysotile nanotubes can then behave as host systems, where their large interchannel separation is actually expected to prevent the interaction between individual guest metallic nanoparticles and act as a confining barrier. Chrysotile nanotubes have been filled with molten metals such as Hg, Pb, Sn, semimetals, Bi, Te, Se, and with semiconductor materials such as InSb, CdSe, GaAs, and InP using both high-pressure techniques and metal-organic chemical vapor deposition. Under hydrothermal conditions chrysotile nanocrystals have been synthesized as a single phase and can be utilized as a very suitable for nanowires preparation filling their inner nanometer-sized cavity with metallic nanoparticles. In this research work we have synthesized and characterized Stoichiometric synthetic chrysotile nanotubes have been partially filled with bi and monometallic highly monodispersed nanoparticles with diameters ranging from 1,7 to 5,5 nm depending on the core composition (Au, Au4Ag1, Au1Ag4, Ag). In the case of 4 methylbenzenethiol protected silver nanoparticles, the filling was carried out by convection and capillarity effect at room temperature and pressure using a suitable organic solvent. We have obtained new interesting nanowires constituted of metallic nanoparticles filled in inorganic nanotubes with a inner cavity of 7 nm and an isolating wall with a thick ranging from 7 to 21 nm.

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4

Wang, Junwei. "Chemical doping of metal oxide nanomaterials and characterization of their physical-chemical properties". Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1333829935.

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5

Bouvet-Marchand, Agathe. "Syntheses, preparations and physico-chemical characterizations of functional hybrid thin layers". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0338.

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Pour répondre aux défis de la science, des matériaux toujours plus performants sont nécessaires. Néanmoins, les plastiques ou les métaux ne suffisent pas à eux seuls à apporter une solution aux problématiques actuelles qui exigent des matériaux peu coûteux, facilement mis en forme, industrialisables et aux propriétés variées (conductivité électronique, transparence, auto-nettoyant, anti-corrosif etc.). En revanche, l'association plastique-métal ou "hybride" semble s'imposer ces dernières années comme une voie prometteuse. En effet, dans ces matériaux, les propriétés des deux composés ne font pas que s'additionner mais une synergie se forme conduisant à des propriétés uniques. Atteindre un tel effet synergétique n'est cependant pas aisé et nécessite de contrôler avec précision les interactions entre le plastique et le métal. Lors de cette thèse, des revêtements hybrides de très faible épaisseurs (du nanomètre ou micromètre) ont été préparés pour répondre à des problématiques variées. Des matériaux destinés à être utilisés dans des capteurs de reconnaissance digitale de très haute résolution, à encapsuler des milieux biologiques pour leur observation en microscopie, à collecter un signal électrique ou encore dédiés à protéger des écrans de l'eau ont été élaborés. Afin de répondre aux cahiers des charges de ces différentes applications, des molécules spécifiques ont été synthétisées dans chaque cas pour permettre une bonne interaction avec les composants inorganiques et leur assemblage en un matériau a été minutieusement ajusté pour conduire aux propriétés souhaitées
To face the technical challenges of our time, more and more performing materials are needed. However, neither plastic nor metals are sufficient to answer the different current problematic that require materials to be cheap, easily processable, industrializable with oustanding properties (electronic conductivity, transparency, self-cleaning, anti-corrosive etc.). These last years, the association plastic-metal or "hybrid" appears to be a promising route. Indeed, in these materials, not only properties of the plastic and metal are added but a synergy happens leading to unique properties. However, reaching this synergetic effect is not a straightforward task and an accurate control of the interaction between the two counterparts is crucial. During this Ph.D, thin hybrid films (from nanometer to micrometer) were prepared to answer various industrial and academic problematic. Materials dedicated to be used in fingerprint-sensor with very high resolution, to encapsulate biological media for electronic microscopy analysis, to collect an electrical signal or prevent water degradation on screens were elaborated. In order to answer the specific requirements of these different applications, particular molecules were designed to enable a good interaction with the inorganic components and their assembly was carefully adjusted to obtain the desired properties in the resulting material

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6

Bouvet-Marchand, Agathe. "Syntheses, preparations and physico-chemical characterizations of functional hybrid thin layers". Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0338.

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Pour répondre aux défis de la science, des matériaux toujours plus performants sont nécessaires. Néanmoins, les plastiques ou les métaux ne suffisent pas à eux seuls à apporter une solution aux problématiques actuelles qui exigent des matériaux peu coûteux, facilement mis en forme, industrialisables et aux propriétés variées (conductivité électronique, transparence, auto-nettoyant, anti-corrosif etc.). En revanche, l'association plastique-métal ou "hybride" semble s'imposer ces dernières années comme une voie prometteuse. En effet, dans ces matériaux, les propriétés des deux composés ne font pas que s'additionner mais une synergie se forme conduisant à des propriétés uniques. Atteindre un tel effet synergétique n'est cependant pas aisé et nécessite de contrôler avec précision les interactions entre le plastique et le métal. Lors de cette thèse, des revêtements hybrides de très faible épaisseurs (du nanomètre ou micromètre) ont été préparés pour répondre à des problématiques variées. Des matériaux destinés à être utilisés dans des capteurs de reconnaissance digitale de très haute résolution, à encapsuler des milieux biologiques pour leur observation en microscopie, à collecter un signal électrique ou encore dédiés à protéger des écrans de l'eau ont été élaborés. Afin de répondre aux cahiers des charges de ces différentes applications, des molécules spécifiques ont été synthétisées dans chaque cas pour permettre une bonne interaction avec les composants inorganiques et leur assemblage en un matériau a été minutieusement ajusté pour conduire aux propriétés souhaitées
To face the technical challenges of our time, more and more performing materials are needed. However, neither plastic nor metals are sufficient to answer the different current problematic that require materials to be cheap, easily processable, industrializable with oustanding properties (electronic conductivity, transparency, self-cleaning, anti-corrosive etc.). These last years, the association plastic-metal or "hybrid" appears to be a promising route. Indeed, in these materials, not only properties of the plastic and metal are added but a synergy happens leading to unique properties. However, reaching this synergetic effect is not a straightforward task and an accurate control of the interaction between the two counterparts is crucial. During this Ph.D, thin hybrid films (from nanometer to micrometer) were prepared to answer various industrial and academic problematic. Materials dedicated to be used in fingerprint-sensor with very high resolution, to encapsulate biological media for electronic microscopy analysis, to collect an electrical signal or prevent water degradation on screens were elaborated. In order to answer the specific requirements of these different applications, particular molecules were designed to enable a good interaction with the inorganic components and their assembly was carefully adjusted to obtain the desired properties in the resulting material

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7

Brooker, Michael R. "Physical and Chemical Characterization of Self-Developing Agricultural Floodplains". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1513778530623727.

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8

Vereš, Ján, Štefan Jakabský e Vladimír Šepelák. "Chemical, physical, morphological and structural characterization of blast furnace sludge". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188184.

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9

Vereš, Ján, Štefan Jakabský e Vladimír Šepelák. "Chemical, physical, morphological and structural characterization of blast furnace sludge". Diffusion fundamentals 12 (2010) 88, 2010. https://ul.qucosa.de/id/qucosa%3A13909.

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10

RISI, GIULIA. "PHYSICAL-CHEMICAL CHARACTERIZATION OF POLYSACCHARIDES AND THEIR INTERACTION WITH PROTEINS". Doctoral thesis, Università degli studi di Pavia, 2020. http://hdl.handle.net/11571/1318349.

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I glicosamminoglicani sono polisaccaridi lineari ad alta densità di carica negativa, caratteristica che permette loro di interagire facilmente con proteine e grazie a questa interazione sono in grado di svolgere importanti funzioni biologiche oltre che di esercitare attività farmacologiche; ad esempio leparina grazie alla sua interazione specifica con la proteina antitrombina è uno dei più potenti e utilizzati farmaci anticoagulanti. Il presente lavoro di tesi si propone di caratterizzare principalmente glicosamminoglicani e loro miscele, seguendo due linee di ricerca. La prima linea di ricerca, oggetto dei primi due anni di dottorato, è consistita nello studio, validazione e ottimizzazione di metodi cromatografici per esclusione dimensionale volti alla valutazione della distribuzione di peso molecolare di campioni di eparina a diversa lunghezza di catena e provenienti da differenti sorgenti animali (primo anno), e di miscele di eparina e dermatan solfato (secondo anno). Questo studio nasce considerando la natura eterogena e polidispersa dei polisaccaridi, per i quali la distribuzione del peso molecolare ricopre un ruolo fondamentale nella loro applicabilità in campo farmacologico; da qui, la necessità di avere metodiche in grado di valutare questo parametro il più correttamente possibile. A tale scopo sono stati presi in considerazione e sono stati comparati sia metodi richiedenti una classica calibrazione convenzionale, consistenti nella costruzione di una curva di calibrazione con un set di standard certificati, e conseguente ottenimento di una distribuzione dei pesi molecolari relativa alla curva, sia metodi assoluti che richiedono un detector come il Light Scattering che non necessita di alcuna calibrazione delle colonne cromatografiche utilizzate e valuta il peso molecolare dallo scattering delle particelle in soluzione. La seconda linea di ricerca, sviluppata lungo tutti e tre gli anni di dottorato, ruota attorno alla caratterizzazione chimico-fisica del complesso eparina/fattore piastrinico 4 (PF4), causa di uno dei peggiori effetti collaterali associati alla terapia con eparina, la Trombocitopenia eparina-indotta (HIT). Poiché tale complesso è influenzato sia dalla lunghezza di catena delleparina, sia dalla sua carica superficiale, le due principali tecniche utilizzate per studiarlo sono state la Spettroscopia di Correlazione Fotonica (PCS) e la valutazione del Potenziale Zeta, sviluppando ed ottimizzando dei metodi basati sulla titolazione di una concentrazione fissa di PF4 con diverse concentrazioni di eparina volti non solo allottenimento di una indicazione sul rapporto proteina/eparina (PHR) considerabile massimo per la formazione di un complesso riconoscibile da quegli anticorpi scatenanti HIT, ma anche in grado di discriminare tra eparine a diversa lunghezza di catena (primo anno). Tali metodiche sono state poi validate anche per miscele più complesse e per polisaccaridi non appartenenti alla famiglia dei glicosamminoglicani (terzo anno). Infine, è stata ottenuta una prima valutazione dei parametri termodinamici dellinterazione eparina/PF4 mediante Titolazione Calorimetrica Isotermica (ITC) volta allo sviluppo di un metodo in grado di distinguere eparine a diversa lunghezza di catena (secondo anno), tecnica ripresa anche per la valutazione termodinamica di polisaccaridi non appartenenti alla famiglia dei glicosamminoglicani (terzo anno).

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11

Toughchi, Mehrdad Abbasi. "Chemical quality of Iranian tea. Comparison with foreign tea". Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/15091.

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12

Salberg, Alesia C. "Characterization of the Physical and Chemical Networks in Filled Rubber Compounds". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1258383036.

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13

GONTIJO, LAYNE OLIVEIRA DE LUCAS. "PHYSICAL CHEMICAL CHARACTERIZATION OF THE MERCERIZING EFFECT ON PIAÇAVA FIBERS ATTALLEA FUNIFERA". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35995@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
O uso de fibras naturais como reforço em materiais compósitos vem ganhando destaque em diversos setores industriais, principalmente devido às restrições ambientais, que impõem requisitos legais relacionados ao uso de produtos sintéticos, visando a reutilização e substituição de matérias-primas não renováveis. As fibras naturais são biodegradáveis e apresentam propriedades e morfologia muito atraentes. Dentre elas, novas categorias de fibras estão sendo investigadas, como é o caso da fibra de piaçava, oriunda da palmeira Attalea funifera Martius. Sua fibra longa, lisa, resistente e de textura impermeável apresenta propriedades mecânicas semelhantes às fibras de coco, amplamente utilizadas pela indústria. Um dos desafios no uso dessas fibras como reforço em materiais compósitos é melhorar a interação entre a fibra e matriz polimérica, uma vez que as fibras naturais são hidrofílicas e as matrizes são hidrofóbicas, desenvolvendo interfaces fracas. Em alguns casos, tratamentos químicos específicos (por exemplo, o método de mercerização) podem melhorar esta interface, removendo parte da lignina e celulose de fibras, tornando a superfície rugosa compatível com a matriz polimérica. Neste trabalho, vários parâmetros foram avaliados através de MEV, microCT, FTIR e microscopia de varredura laser confocal (CLSM) da fibra de piassava antes e depois da mercerização em solução aquosa de NaOH a 10 por cento em peso. As análises permitiram avaliar que o tratamento alcalino promoveu uma limpeza profunda na superfície das fibras, removendo protrusões de sílicas do vegetal, com aumento do índice de cristalinidade, além de remover frações de lignina, hemicelulose, celulose, ceras e outras impurezas, causando desfibrilação do tecido. Também houve aumento da área superficial, rugosidade e porosidade das fibras após o tratamento químico.
The use of natural fibers to reinforce composite materials has been gaining considerable notice in many industrial fields. This is mainly due to environmental restrictions, which impose legal requirements related to the use of synthetic products, aiming at the reuse and replacement of non-renewable raw materials, which cause less damage to the environment. Natural fibers are biodegradable, renewable resources with very attractive properties and morphology. Among them, new categories of fibers are being investigated, as the case of piassava fiber, from the palm of Attalea funifera Martius. Its long, smooth, sturdy and waterproof textured fiber has similar mechanical properties to the coconut fibers widely used in the industry. One of the challenges in using these fibers as reinforcement in composite materials is to improve the interaction between fiber and polymer matrix, since the natural fibers are hydrophilic and the matrices are hydrophobic, developing weak interfaces. In some cases, specific chemical treatments (eg the mercerization method) can improve this interface by removing part of the lignin and cellulose from fibers, making the rough surface compatible with the polymer matrix. In this work, several parameters were evaluated through MEV, microCT, FTIR and confocal laser scanning microscopy (CLSM) of piassava fibers, before and after mercerization with 10 percent by weight aqueous NaOH solution. The analyzes allowed to evaluate that the alkaline treatment promoted a deep cleaning on the surface of the fibers, removing protrusions of silica from the vegetable, besides removing lignin, hemicellulose, cellulose, waxes and other impurities, causing tissue defibrillation. Also, it was able to increase the surface area, roughness and porosity of the fibers after chemical treatment.

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14

Sandoval, Kathia a. "Physical and Chemical Characterization of Crude Oil-Water Mixtures: Understanding the Effects of Interfacial Process to Chemical Bioavailability". FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2464.

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This work detailed the physical and chemical characterization of oil water mixtures prepared using fresh and weathered Macondo related oils under different conditions of mixing energy/time and in the presence/absence of chemical dispersants. The results indicated that WAFs produced consistent, droplet free solutions for both source and weathered oils with concentration ranges that represented the soluble components of the oil used. Chemically enhanced WAFs prepared with the source oil generated a large amount of micron-size droplets; however the viscosity of the weathered oils were a limiting factor for the preparation of CEWAFs with weathered oils. Droplet size distributions were influenced by the amount of energy in the system and the oil weathering stage, when high energy WAFs were made the increase in weathering of the oil resulted in the formation of smaller droplets that were more stable over time.

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15

Thierry-Jebali, Nicolas. "Caractérisations et modélisations physiques de contacts entre phases métalliques et Nitrure de Gallium semi-conducteur". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00744661.

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Les composés III-N, et le Nitrure de Gallium (GaN) en particulier, sont devenus des matériaux semi conducteurs importants pour l'ensemble de l'humanité. Depuis la fin des années 1990, ils ont permis le développement de composants électroluminescents fiables, diodes LED et diodes laser, qui constituent une solution de remplacement à rendement énergétique amélioré par rapport aux composants à incandescence. Il est possible qu'ils jouent aussi un rôle dans les nouvelles générations de composants pour l'électronique de puissance. Lors du développement des composants, des recherches expérimentales permettent de trouver assez rapidement des solutions pour réaliser les briques technologiques indispensables, mais le temps manque pour comprendre les mécanismes physiques mis en jeu. Nos travaux ont eu pour objectif d'approfondir la compréhension de l'influence de la structure physico-chimique sur les propriétés électriques des contacts ohmiques et Schottky sur GaN de type N.

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16

Sanchez, Javier. "Characterization of activated carbon produced from coffee residues by chemical and physical activation". Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32872.

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Activated carbons are one of the most used adsorbents with lots of applications in many sectors. Activated carbons can be produced from lignocellulosic materials with a large content of carbon. Coffee is the second trade most consumed all over the world; hence their residues can be treated in order to give a value. In order to evaluate the viability of using coffee residues as precursor have been carried out experiments by chemical and physical activation. The chosen chemical was phosphoric acid, a dehydrating chemical widely used in production of activated carbons while steam was selected for a physical activation. In this study have been studied the temperature activation and the concentration of chemical as the main factors. One of the advantages of using a chemical is the lower activation temperature; in this study were selected 500ºC, 600ºC and 700ºC while samples treated by steam were 600ºC, 700ºC and 800ºC. Water is a reactive agent that removes volatile compounds and makes wide pores whereas chemicals create linkages with the carbon and volatile compounds enhancing their porosity. Hence, have been studied the following impregnation concentrations 30%, 40% and 50% in order to evaluate their properties as adsorbents. Isotherms were analysed to determine their surface area and pore size distribution. Also were determined the pore size and pore volume for all samples.

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17

Choo, Hyunwook. "Engineering behavior and characterization of physical-chemical particulate mixtures using geophysical measurement techniques". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52178.

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Natural geomaterials exhibit a wide range in size, physical properties, chemical properties, and mechanical behaviors. Soils that are composed of mixtures of particles with different physical and chemical properties pose a challenge to characterization and quantification of the engineering properties. This study examined the behavior of particulate mixtures composed of differently sized silica particles, mixtures composed of aluminosilicate and organic carbon particles, and mixtures composed of particles with approximately three orders of magnitude difference in particle size. This experimental investigation used elastic, electromagnetic, and thermal waves to characterize and to quantify the small to intermediate strain behavior of the mixtures. The mechanical property of stiffness of mixed materials (e.g. binary mixtures of silica particles and fly ashes with various carbon and biomass contents) was evaluated through the stiffness of active grain contacts, and the stiffness of particles which carry applied load, using the physical concepts of intergranular void ratio and interfine void ratio. Additionally, the change in both contact mode/stiffness and electrical property due to the presence of nano-sized particles (i.e., iron oxides) on the surface of soil grains was evaluated according to applied stress, packing density, iron coating density, and substrate sand particle size. Finally, the biomass fraction and total organic carbon content of mixtures was used to quantify the electrical and thermal conductivities when particulate organic was mixed with aluminosilicate particles.

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18

Malloy, Quentin Gerald James. "Chemical and physical characterization of secondary organic aerosol formation from select agricultural emissions". Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=33&did=1871857121&SrchMode=1&sid=2&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270140114&clientId=48051.

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19

Marchetti, Marco <1980&gt. "Design, synthesis and Chemical-physical characterization of photocatalytic inorganic nanocrystals for technological applications". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5737/2/marchetti_marco_tesi.pdf.

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This work was based on the synthesis and characterization of innovative crystals for biomedical and technological applications. Different types of syntheses were developed in order to obtain crystals with high photocatalytic properties. A hydrothermal synthesis was also processed to correlate the chemical-physical characteristics with synthesis parameters obtaining synthesis of nanoparticles of titanium dioxide with different morphology, size and crystalline phase depending on the variation of the synthesis parameters. Also a synthesis in water at 80 °C temperature and low pressure was developed from which anatase containing a small percentage of brookite nanoparticles were obtained, presenting a high photocatalytic activity. These particles have been used to obtain the microcrystals formed by an inorganic core of hydroxyapatite surface covered by TiO2 nanoparticles. Micrometer material with higher photocatalytic has been produced. The same nanoparticles have been functionalized with resorcinol oxidized in order to increase the photocatalytic efficiency. Photodegradation test results have confirmed this increase. Finally, synthetic nanoparticles with a waterless synthesis using formic acid and octanol, through esterification "in situ" were synthesized. Nanoparticles superficially covered by carboxylic residues able to bind a wide range of molecules to obtain further photocatalytic properties were obtained.

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20

Marchetti, Marco <1980&gt. "Design, synthesis and Chemical-physical characterization of photocatalytic inorganic nanocrystals for technological applications". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5737/.

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This work was based on the synthesis and characterization of innovative crystals for biomedical and technological applications. Different types of syntheses were developed in order to obtain crystals with high photocatalytic properties. A hydrothermal synthesis was also processed to correlate the chemical-physical characteristics with synthesis parameters obtaining synthesis of nanoparticles of titanium dioxide with different morphology, size and crystalline phase depending on the variation of the synthesis parameters. Also a synthesis in water at 80 °C temperature and low pressure was developed from which anatase containing a small percentage of brookite nanoparticles were obtained, presenting a high photocatalytic activity. These particles have been used to obtain the microcrystals formed by an inorganic core of hydroxyapatite surface covered by TiO2 nanoparticles. Micrometer material with higher photocatalytic has been produced. The same nanoparticles have been functionalized with resorcinol oxidized in order to increase the photocatalytic efficiency. Photodegradation test results have confirmed this increase. Finally, synthetic nanoparticles with a waterless synthesis using formic acid and octanol, through esterification "in situ" were synthesized. Nanoparticles superficially covered by carboxylic residues able to bind a wide range of molecules to obtain further photocatalytic properties were obtained.

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21

Barbieri, Sara <1981&gt. "Characterization of Food Products by Chemical, Physical and Sensory Properties: a Combined Approach". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7458/1/Barbieri_Sara_Tesi.pdf.

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The aim of this doctoral dissertation is to show the results of a combined approach related to the characterization of food products by chemical, physical and sensory properties. The two main objectives are the discrimination of food products, according to analytical characteristics (chemical, physical and sensory) and related to compositional and/or technological variables, and the relationship study between the sensory profile and some chemical-physical characteristics used for valorization and quality testing of a food product. The research method leads to investigate the main drivers of the consumer's overall liking. The strategy implemented highlights the effectiveness of sensory and instrumental methodologies in food quality investigation due to the complementary information that they can provide. Some trials are related to the study on sunflower and hazelnut cold-pressed oils, the investigation on the effectiveness of the Flash Gas Chromatography Electronic Nose (FGC E-nose) as a tool to rapidly discriminate among commercial virgin olive oils, the characterization of Taralli, the characterization of different commercial categories of Italian cooked hams, the quality evaluation and consumers’ acceptance of a set of different extra virgin olive oils purchased on the Italian market, and the possible influence of aromatization process on the quality of “flavored olive oils”. The obtained results feature specific sensory attributes and chemical-physical properties that contribute to better defining product characteristics, the perception of food quality and its typicality. These investigations highlight the importance of familiarity with the products and eating habits in the definition of consumer behavior. The findings reveal an important insight for which additional efforts should be addressed towards dissemination of accurate information about the relationship between product composition and sensory characteristics.

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22

Lim, McKenzie C. H. "Chemical and physical characterization of aerosols from the exhaust emissions of motor vehicles". Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16428/1/McKenzie_Lim_Thesis.pdf.

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The number concentration and size distribution of particles in Brisbane have been studied extensively by the researchers at The International Laboratory for Air Quality and Health, Queensland University of Technology (Morawska et al., 1998, 1999a, 1999b). However, the comprehensive studies of chemical compositions of atmospheric particles, especially with regard to the two main classes of pollutants (polycyclic aromatic hydrocarbons and trace elements), that are usually of environmental and health interest, have not been fully undertaken. Therefore, this thesis presents detailed information on polycyclic aromatic hydrocarbons (PAHs) and elemental compositions of vehicle exhausts and of urban air in Brisbane. The levels of polycyclic aromatic hydrocarbons (PAHs) and elements in three of Brisbane's urban sites (Queensland University of Technology, Woolloongabba and ANZ stadium sites) were measured. The most common PAHs found in all sites were naphthalene, phenanthrene, anthracene, fluoranthene, pyrene and chrysene while Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Si, Sn, Sr and Zn were the most common elements detected in the total suspended particles and fine particle (PM2.5). With the aid of multivariate analysis techniques, several outcomes were obtained. For example: -- Major human activities such as vehicular and industrial sources were the most contributing pollution sources in Brisbane. However, these two sources have different influential strength on the compositions of the polycyclic aromatic hydrocarbons and trace inorganic elements found in the urban air. -- Woolloongabba bus platform was the most polluted site on the basis of the elemental and PAH compositions in its air samples while QUT site was the worst polluted site in terms of PM2.5 elemental contents. These results demonstrated that the impact of traffic related pollutants on Brisbane's urban air is significant. This led to the investigations of the direct emissions of pollutants from exhaust vehicular source in the second part of this research work. The exhaust studies included the investigations of PAHs, trace inorganic elements and particles. At the time of the study, the majority of vehicles in Brisbane used low sulfur diesel (LSD) fuel or unleaded petrol (ULP). However, the importance of vehicles using ultra low sulfur diesel (ULSD) and liquefied petroleum gas (LPG) is constantly growing. Therefore, the exhaust emission studies on chassis dynamometer from heavy duty non-catalyst-equipped buses powered by LSD and ULSD with 500 ppm and 50 ppm sulfur contents respectively as well as passenger cars powered by ULP and LPG were explored. The outcomes of such studies are summarized as follows: -- Naphthalene, acenaphthene, acenaphthylene, anthracene, phenanthrene, fluorene, fluoranthene and pyrene were frequently emitted by the buses powered by LSD and ULSD. However, buses powered by ULSD emitted 91% less PAHs than those powered by LSD. On the other hand, Mg, Ca, Cr, Fe, Cu, Zn, Ti, Ni, Pb, Be, P, Se, Ti and Ge were found in measurable quantities in the exhaust of the buses. The emissions of the elements were found to be strongly influenced by the engine driving conditions of the buses and fuel parameters such as sulfur content, fuel density and cetane index. -- Naphthalene, fluorene, phenanthrene, anthracene, pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene were predominantly emitted by ULP and LPG cars. On the average, the total emission factors of PAHs from LPG cars were generally lower than those of ULP cars, but given the large variations in the emission factors of cars powered by the same type of fuel, differences in the emission factors from both car types were statistically insignificant. In general, platinum group elements and many other elements were found in the exhausts of cars powered by both fuels. Emissions of inorganic elements from the cars were dependent on the type and the mileage of the cars. For example, ULP cars generally emitted higher levels of Cu, Mg, Al and Zn while LPG cars emitted higher level of V. In addition, cars with higher mileages were associated with higher emissions of the major elements (Zn, Al, Fe, V and Cu). -- Buses powered by ULSD usually emitted fewer particles, which were generally 31% to 59% lower than those emitted by LSD powered buses. Similarly, cars powered by LPG emitted less particles from those powered by ULP fuel. However, more nanoparticles (those with aerodynamic diameters of less than 50 nm) were emitted by LPG powered cars than their ULP counterparts. Health effect assessment of the exhaust PAHs was evaluated in terms of benzo(a)pyrene toxicity equivalent (BAPeq). The potential toxicities of PAHs emitted by ULSD powered buses were generally lower than those emitted by their LSD counterparts. A similar trend with lower emissions of PAHs from LPG cars than from ULP cars was observed when otherwise identical passenger cars were powered by LPG and ULP fuels. In summary, this thesis has shown that the majority of airborne particles found around Brisbane have anthropogenic origins, particularly vehicle emissions, and that fuel or lubricant formulations and engine operating conditions play important roles in the physical and chemical characteristics of pollutants emitted by vehicles. The implications of these results on worldwide strategies to reduce the environmental and health effects of particles emitted by motor vehicles were discussed. In this regard, direct emission measurements from vehicles powered by LSD, ULSD, ULP and LPG unveiled the relative environmental benefits associated with the use of ULSD in place of LSD to power diesel engines, and of LPG in place of ULP to power passenger cars.

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23

Lim, McKenzie C. H. "Chemical and physical characterization of aerosols from the exhaust emissions of motor vehicles". Queensland University of Technology, 2007. http://eprints.qut.edu.au/16428/.

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The number concentration and size distribution of particles in Brisbane have been studied extensively by the researchers at The International Laboratory for Air Quality and Health, Queensland University of Technology (Morawska et al., 1998, 1999a, 1999b). However, the comprehensive studies of chemical compositions of atmospheric particles, especially with regard to the two main classes of pollutants (polycyclic aromatic hydrocarbons and trace elements), that are usually of environmental and health interest, have not been fully undertaken. Therefore, this thesis presents detailed information on polycyclic aromatic hydrocarbons (PAHs) and elemental compositions of vehicle exhausts and of urban air in Brisbane. The levels of polycyclic aromatic hydrocarbons (PAHs) and elements in three of Brisbane's urban sites (Queensland University of Technology, Woolloongabba and ANZ stadium sites) were measured. The most common PAHs found in all sites were naphthalene, phenanthrene, anthracene, fluoranthene, pyrene and chrysene while Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Si, Sn, Sr and Zn were the most common elements detected in the total suspended particles and fine particle (PM2.5). With the aid of multivariate analysis techniques, several outcomes were obtained. For example: -- Major human activities such as vehicular and industrial sources were the most contributing pollution sources in Brisbane. However, these two sources have different influential strength on the compositions of the polycyclic aromatic hydrocarbons and trace inorganic elements found in the urban air. -- Woolloongabba bus platform was the most polluted site on the basis of the elemental and PAH compositions in its air samples while QUT site was the worst polluted site in terms of PM2.5 elemental contents. These results demonstrated that the impact of traffic related pollutants on Brisbane's urban air is significant. This led to the investigations of the direct emissions of pollutants from exhaust vehicular source in the second part of this research work. The exhaust studies included the investigations of PAHs, trace inorganic elements and particles. At the time of the study, the majority of vehicles in Brisbane used low sulfur diesel (LSD) fuel or unleaded petrol (ULP). However, the importance of vehicles using ultra low sulfur diesel (ULSD) and liquefied petroleum gas (LPG) is constantly growing. Therefore, the exhaust emission studies on chassis dynamometer from heavy duty non-catalyst-equipped buses powered by LSD and ULSD with 500 ppm and 50 ppm sulfur contents respectively as well as passenger cars powered by ULP and LPG were explored. The outcomes of such studies are summarized as follows: -- Naphthalene, acenaphthene, acenaphthylene, anthracene, phenanthrene, fluorene, fluoranthene and pyrene were frequently emitted by the buses powered by LSD and ULSD. However, buses powered by ULSD emitted 91% less PAHs than those powered by LSD. On the other hand, Mg, Ca, Cr, Fe, Cu, Zn, Ti, Ni, Pb, Be, P, Se, Ti and Ge were found in measurable quantities in the exhaust of the buses. The emissions of the elements were found to be strongly influenced by the engine driving conditions of the buses and fuel parameters such as sulfur content, fuel density and cetane index. -- Naphthalene, fluorene, phenanthrene, anthracene, pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene were predominantly emitted by ULP and LPG cars. On the average, the total emission factors of PAHs from LPG cars were generally lower than those of ULP cars, but given the large variations in the emission factors of cars powered by the same type of fuel, differences in the emission factors from both car types were statistically insignificant. In general, platinum group elements and many other elements were found in the exhausts of cars powered by both fuels. Emissions of inorganic elements from the cars were dependent on the type and the mileage of the cars. For example, ULP cars generally emitted higher levels of Cu, Mg, Al and Zn while LPG cars emitted higher level of V. In addition, cars with higher mileages were associated with higher emissions of the major elements (Zn, Al, Fe, V and Cu). -- Buses powered by ULSD usually emitted fewer particles, which were generally 31% to 59% lower than those emitted by LSD powered buses. Similarly, cars powered by LPG emitted less particles from those powered by ULP fuel. However, more nanoparticles (those with aerodynamic diameters of less than 50 nm) were emitted by LPG powered cars than their ULP counterparts. Health effect assessment of the exhaust PAHs was evaluated in terms of benzo(a)pyrene toxicity equivalent (BAPeq). The potential toxicities of PAHs emitted by ULSD powered buses were generally lower than those emitted by their LSD counterparts. A similar trend with lower emissions of PAHs from LPG cars than from ULP cars was observed when otherwise identical passenger cars were powered by LPG and ULP fuels. In summary, this thesis has shown that the majority of airborne particles found around Brisbane have anthropogenic origins, particularly vehicle emissions, and that fuel or lubricant formulations and engine operating conditions play important roles in the physical and chemical characteristics of pollutants emitted by vehicles. The implications of these results on worldwide strategies to reduce the environmental and health effects of particles emitted by motor vehicles were discussed. In this regard, direct emission measurements from vehicles powered by LSD, ULSD, ULP and LPG unveiled the relative environmental benefits associated with the use of ULSD in place of LSD to power diesel engines, and of LPG in place of ULP to power passenger cars.

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24

ROSESTOLATO, Davide. "Chemical and Physical Characterization of Electrocatalysts based on Iridium Oxide and prepared by Sol-Gel and Physical Vapor Deposition". Doctoral thesis, Università degli studi di Ferrara, 2014. http://hdl.handle.net/11392/2389035.

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25

Cassity, Kelby Brandan. "CHEMICAL MODIFICATION AND CHARACTERIZATION OF CARBON NANOTUBES". UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/73.

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Carbon nanotubes (CNTs) are a relatively new allotrope of carbon that possess very unique and exciting physical characteristics. However, much is still unknown regarding their physical structure and chemical reactivity. The focus of this dissertation is to utilize the chemical modification of these filamentous carbon structures as a probe to investigate the structure and reactivity of carbon nanotubes. Also discussed is the ability of CNTs, once chemically modified, to interact with specific polymer matrices and how the addition of modified and unmodified CNTs affects the physical properties of these matrices.

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26

Ozkan, Alp. "CO2 splitting in a dielectric barrier discharge plasma: understanding of physical and chemical aspects". Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/239300.

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Le dioxyde de carbone, principal gaz à effet de serre lié aux activités humaines, est considéré comme l’un des gaz les plus problématiques pour notre environnement ces dernières années, principalement à cause du réchauffement climatique qu’il engendre. C’est pour cette raison que l’augmentation de sa teneur dans l’atmosphère nous concerne tous quant aux conséquences futures pour notre planète. Afin de limiter l’émission de CO2, sa conversion en composés à valeur ajoutée présente un grand intérêt et est possible notamment via des procédés plasmas. Plus particulièrement, les décharges à barrière diélectrique (DBD) sont utilisées depuis quelques années pour générer des plasmas froids opérant à pression atmosphérique, principalement pour des applications en traitement de surface, mais également pour le traitement d’effluents gazeux.Lors de cette thèse, nous nous sommes focalisés sur le processus de dissociation du CO2 en CO et O2 via un réacteur DBD à flux continu et avons analysé sa conversion et son efficacité énergétique via différentes études. Celles-ci ont été réalisées grâce à plusieurs méthodes de diagnostic, comme par exemple la spectrométrie de masse utilisée pour déterminer la conversion et l’efficacité du processus, la spectroscopie d’émission optique, l’oscilloscope pour une caractérisation électrique, etc. afin d’avoir une meilleure compréhension du comportement des décharges CO2.Dans un premier temps, nous avons réalisé une étude détaillée d’un plasma CO2 pur où nous avons fait varier différents paramètres, tels que le temps de résidence, la fréquence, la puissance, la pulsation de la haute tension et l’épaisseur et la nature du diélectrique. Le CO2 donne lieu généralement à une décharge filamentaire, consistant en de nombreuses microdécharges réparties au niveau de la zone du plasma. Celles-ci constituent la principale source de réactivité dans une DBD. Un aperçu détaillé de l’aspect physique de ces microdécharges a été réalisé grâce à la caractérisation électrique, permettant de mieux comprendre les propriétés électriques de la décharge et des microdécharges. En effet, nous avons pu déterminer l’importance de la tension présente au niveau du plasma, de l’intensité du courant plasma, du nombre de microdécharges et de leur temps de vie sur l’efficacité du processus de dissociation de CO2.Ensuite, nous avons conclu ce travail avec des études combinant le CO2 en phase plasma avec de l’eau ou du méthane afin de produire des molécules à valeur ajoutée telles que les syngas (CO et H2), mais aussi des hydrocarbures (C2H6, C2H4, C2H2 et CH2O) dans le cas de l’ajout du méthane. A travers ces études, nous avons obtenu une meilleure connaissance de la chimie et de la physique qui ont lieu dans ce type de plasma.
Carbon dioxide appears as one of the most problematic gases for the environment, mostly because it is responsible for global warming. This is why its increasing concentration into the atmosphere, mainly due to anthropogenic activities, is a real concern for planet Earth. In order to prevent the release of large amounts of CO2, its conversion into value-added products is of great interest. In this context, plasma-based treatments using dielectric barrier discharges (DBDs) are nowadays more and more used for the conversion of this gas. In this thesis, we investigated the CO2 splitting process into CO and O2 via a flowing cylindrical DBD and we studied its conversion and energy efficiency by means of several diagnostic methods, such as mass spectrometry to determine the conversion and energy efficiency of the process, optical emission spectroscopy for gas temperature measurements, and an oscilloscope for electrical characterization, in order to obtain a better understanding of the CO2 discharge itself.First, we focused on an extensive experimental study of a pure CO2 plasma where different parameters were varied, such as the gas residence time, the operating frequency, the applied power, the pulsation of the AC signal, the thickness and the nature of the dielectric. CO2 discharges typically exhibit a filamentary behavior, consisting of many microdischarges, which act as the main source of reactivity in a DBD. A detailed insight in the physical aspects was achieved by means of an in-depth electrical characterization, allowing more insight in the electrical properties of the discharge and more specifically in the microdischarges, which are spread out throughout the active zone of the plasma. It was found throughout this work that the plasma voltage, which reflects the electric field and thus determines how the charged particles are accelerated, the plasma current, which reflects the electron density, but also the number of microdischarges and their average lifetime, play an important role in the efficiency of the CO2 dissociation process. It was revealed that the microdischarge number is important as it represents the repartition of the locations of reactivity. Indeed, as the microfilaments are more spread out in the same discharge volume, the probability for the CO2 molecules to pass through the reactor and interact with at least one microdischarge filament becomes more important at a larger number of microfilaments.The second part of the thesis was dedicated to discharges combining CO2 and H2O or CH4, both being hydrogen source molecules. The combined CO2/H2O or CO2/CH4 conversion allows forming value-added products like syngas (CO and H2), but also hydrocarbons (C2H6, C2H4, C2H2 and CH2O), at least in the presence of methane. Throughout this study, we tried to obtain a better knowledge of the chemistry and physic behind these conversion processes.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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27

Kokubo, Shinsuke. "Characterization of Physical and Chemical Properties of Synthetic Polymer using Ion Mobility-Mass Spectrometry". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3FAC-5.

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28

Barzegar, HamidReza. "Synthesis and Characterization of Carbon Based One-Dimensional Structures : Tuning Physical and Chemical Properties". Doctoral thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97551.

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Carbon nanostructures have been extensively used in different applications; ranging from electronic and optoelectronic devices to energy conversion. The interest stems from the fact that covalently bonded carbon atoms can form a wide variety of structures with zero-, one- and two-dimensional configuration with different physical properties. For instance, while fullerene molecules (zero-dimensional carbon structures) realize semiconductor behavior, two-dimensional graphene shows metallic behavior with exceptional electron mobility. Moreover the possibility to even further tune these fascinating properties by means of doping, chemical modification and combining carbon based sub-classes into new hybrid structures make the carbon nanostructure even more interesting for practical application. This thesis focuses on synthesizing SWCNT and different C60 one-dimensional structures as well as tuning their properties by means of different chemical and structural modification. The purpose of the study is to have better understanding of the synthesis and modification techniques, which opens for better control over the properties of the product for desired applications. In this thesis carbon nanotubes (CNTs) are grown by chemical vapor deposition (CVD) on iron/cobalt catalyst particles. The effect of catalyst particle size on the diameter of the grown CNTs is systematically studied and in the case of SWCNTs it is shown that the chirality distribution of the grown SWCNTs can be tuned by altering the catalyst particle composition. In further experiments, incorporation of the nitrogen atoms in SWCNTs structures is examined. A correlation between experimental characterization techniques and theoretical calculation enable for precise analysis of different types of nitrogen configuration in SWCNTs structure and in particular their effect on growth termination and electronic properties of SWCNTs are studied. C60 one-dimensional structures are grown through a solution based method known as Liquid-liquid interfacial precipitation (LLIP). By controlling the crystal seed formation at the early stage of the growth the morphology and size of the grown C60 one-dimensional structures where tuned from nanorods to large diameter rods and tubes. We further introduce a facile solution-based method to photo-polymerize the as-grown C60 nanorods, and show that such a method crates a polymeric C60 shell around the nanorods. The polymeric C60 shell exhibits high stability against common hydrophobic C60 solvents, which makes the photo-polymerized nanorods ideal for further solution-based processing. This is practically shown by decoration of both as grown and photo-polymerized nanorods by palladium nanoparticles and comparison between their electrochemical activities. The electrical properties of the C60 nanorods are also examined by utilizing a field effect transistor geometry comprising different C60 nanorods. In the last part of the study a variant of CNT is synthesized in which large diameter, few-walled CNTs spontaneously transform to a collapsed ribbon shape structure, the so called collapsed carbon nanotube (CCNT). By inserting C60 molecules into the duct edges of CCNT a new hybrid structure comprising C60 molecules and CCNT is synthesized and characterized. A further C60 insertion lead to reinflation of CCNTs, which eventually form few-walled CNT completely filled with C60 molecules.

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29

Park, Geunhyung. "Characterization of actuator behaviors of ferrogels obtained from physical and chemical cross-linking methods". [Ames, Iowa : Iowa State University], 2008.

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30

CIMO', Giulia. "CHARACTERIZATION OF CHEMICAL AND PHYSICAL PROPERTIES OF BIOCHAR FOR ENERGY PURPOSES AND ENVIRONMENTAL RESTORATION". Doctoral thesis, Università degli Studi di Palermo, 2014. http://hdl.handle.net/10447/90867.

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Biochar production processes as well as its various applications provide numerous benefits to both environment and economy (Lehmann et al., 2006; Basu, 2010). However, understanding the physicochemical structure of this valuable product has to be improved in order to be able to obtain the aforementioned benefits and to avoid environmental costs. In this study, chicken or poultry manure (PM) was chosen as feedstock for biochar preparation. This biomass is traditionally used by farmers as an effective organic fertilizer (Chan et al., 2008). Indeed, it is considered a valuable source for readily available plant nutrients, such as N, P, K and other micronutrients (Huang et al., 2011). Notwithstanding the advantages of PM for increasing soil fertility, there are food safety and environmental concerns about its application in agricultural sites in its unmodified form (Wilkinson et al., 2003; Chan et al., 2008). In fact, the misuse of chicken manure as fertilizer may result in serious environmental problems (Gay et al., 2003), such as human and animal health risks, odors, and leaching of nitrates 4 and other pollutants into groundwater (Fan et al., 2000). For this reason, conversion of chicken manure to char has been proposed as an attractive methodology to reduce PM volume and weight, and its stink (Shinogi and Kanri, 2003; Popov et al., 2004). Some studies have already examined PM biochar characteristics (Uchimiya et al., 2010). Further studies must be performed to evaluate the possibility to use poultry manure chars either as soil amendments or for remediation purposes in order to avoid environmental damages. As already stressed, char characteristics and properties are greatly affected by pyrolysis process and its parameters (mainly process temperature and residence time). These factors are particularly important in determining the nature of the final product and, consequently, its potential value in terms of carbon sequestration, agronomic performance and/or environmental remediation. The project has two main objectives. Firstly, it aims to report about the changes occurring in the chemical properties and in the physical structure of biochars produced from poultry manure when it is obtained at different pyrolysis temperatures and heating times, and how these changes can influence its agronomic or remediation potential. This topic is discussed in Chapters 3 and 4. The second objective of the project is to investigate the potential of three different kinds of biochars, produced from poultry manure, conifer and poplar wood residues, as adsorbents for inorganic contaminants (i.e., heavy metals) for wastewater treatment. In chapter 5, biochar adsorption qualities are evaluated using kinetic (pseudo-first order, pseudo-second-order), equilibrium and isotherms (Langmuir, Freundlich, Toth and RedlichPeterson) models, used to fit experimental data.

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31

Connors, Sandra André. "Chemical and physical characterization of the degradation of vulcanized natural rubber in the museum environment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36018.pdf.

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32

Popovic, Nevena. "Physical and chemical characterization and upgrading of char derived from scrap tires by ultra fast pyrolysis /". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ54949.pdf.

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Di, Silvio Desire. "Physical-chemical characterization of nanoparticles in relevant biological environments and their interactions with the cell surface". Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/58403/.

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Nanoparticles (NPs) are versatile tools for nanomedicine and tuning features such as material, size and charge, imaging and targeting can be accomplished. However, NPs behaviour in vivo is modified upon interaction with the biological matter and formation of a protein corona (PC) coating the NP. The PC determines the NP biological identity and it is the ultimate interface with the surrounding environment. Therefore, a deep characterization of the NPs in biological media is important to predict adverse effects and improve NPs design. The aim of this thesis was to understand the effect of the PC formation from different biological fluids on NP- membranes interactions. For this purpose, core-shell gold and magnetite NPs coated by poly-maleic anhydride and pegylated were characterized my means of scattering, microscopic and spectroscopic techniques. Such NPs were characterized in serum and PC complexes were isolated. Sucrose-gradient ultracentrifugation (UC) was used guaranteeing quantitative recovery of homogeneous NP PC populations, simultaneously present in situ, and a lower impact on the in situ structures compared to conventional centrifugation protocols. NP interactions with supported lipid bilayers (SLB) were investigated by QCM-D and neutron reflectometry allowing resolving at the sub-nanometer scale any structural reorganization of the SLB upon NP application. Carboxylated NPs generally caused lipid hydration with different mechanisms, while HC NPs compared to in situ NPs and pure FBS had a lower impact on the bilayers possibly indicating a major impact of the soft corona. The last part of the project was focused on the PC evolution during simulated in vitro digestion with NPs. UC was suitable to isolate PC complexes from gastric and intestinal phases and SDS-PAGE and LC-MS suggested a PC ability to protect peptides from digestion degradation. The biological impact of the PC complexes was studied by confocal microscopy on Caco-2 cells revealing cells morphological alterations.

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Merkel, Marcel Patrick [Verfasser], e A. [Akademischer Betreuer] Powell. "Synthesis, characterization and physical/chemical properties of polyoxometalate-based materials / Marcel Patrick Merkel ; Betreuer: A. Powell". Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1205001964/34.

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Wessman, Per. "Physico-Chemical Investigations of, and Characterization of Model Membranes for, Lipid-Peptide Interactions". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-89432.

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Phefadu, Kopano Conferance. "Physico-chemical characterization and spatial variability of soils in the research block at University of Limpopo Experimental Farm". Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1686.

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Thesis (MSc. (Soil Science)) -- University of Limpopo, 2015
There exists a considerable level of spatial variability in soil physical and chemical properties within the research block; and the soils are generally shallow. Of all the measured parameters, electrical conductivity, Bray-1 P, exchangeable potassium, calcium and sodium as well as extractable iron and zinc showed a huge percent of variation across the field. Soil variability maps indicated the degree of variability within the research block. The spatial variability of the characterized parameters was significant across the research block. A correlation study was conducted to investigate the relationship between the measured soil physical and chemical properties. Regular soil analyses should be conducted to avoid failure/delay of experiments. It is recommended that inputs such as irrigation and fertilizer application must be varied based on varying soil conditions across the research block.
VLIR project 6 leaders

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Gao, Min. "CHEMICAL CHARACTERIZATION OF SOIL ORGANIC MATTER IN AN OLIGOTROPHIC, SUBTROPICAL, FRESHWATER WETLAND SYSTEM: SOURCES, DIAGENESIS AND PRESERVATION". FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/3625.

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Freshwater wetland soils of the Everglades were studied in order to assess present environmental conditions and paleo-environmental changes using organic geochemistry techniques. Organic matter in dominant vegetation, peat and marl soils was characterized by geochemical means. Samples were selected along nutrient and hydrology gradients with the objective to determine the historical sources of organic matter as well as the extent of its preservation. Effective molecular proxies were developed to differentiate the relative input of organic matter from different biological sources to wetland soils. Thus historical vegetation shifts and hydroperiods were reconstructed using those proxies. The data show good correlations with historical water management practices starting at the turn of the century and during the mid 1900’s. Overall, significant shortening of hydroperiods during this period was observed. The soil organic matter (SOM) preservation was assessed through elemental analysis and molecular characterizations of bulk 13C stable isotopes, solid state 13C NMR spectroscopy, UV-Vis spectroscopy, and tetramethyl ammonium hydroxide (TMAH) thermochemolysis-GC/MS. The relationship of the environmental conditions and degradation status of the soil organic matter (SOM) among the sites suggested that both high nutrient levels and long hydroperiod favor organic matter degradation in the soils. This is probably the result of an increase in the microbial activity in the soils which have higher nutrient levels, while longer hydroperiods may enhance physical/chemical degradation processes. The most significant transformations of biomass litter in this environment are controlled by very early physical/chemical processes and once the OM is incorporated into surface soils, the diagenetic change, even over extended periods of time is comparatively minimal, and SOM is relatively well preserved regardless of hydroperiod or nutrient levels. SOM accumulated in peat soils is more prone to continued degradation than the SOM in the marl soils. The latter is presumably stabilized early on through direct air exposure (oxidation) and thus, it is more refractory to further diagenetic transformations such as humification and aromatization reactions.

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Gao, Min. "Chemical characterization of soil organic matter in an oligotrophic, subtropical, freshwatwer wetland system : sources, diagenesis and preservation". FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/3618.

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Freshwater wetland soils of the Everglades were studied in order to assess present environmental conditions and paleo-environmental changes using organic geochemistry techniques. Organic matter in dominant vegetation, peat and marl soils was characterized by geochemical means. Samples were selected along nutrient and hydrology gradients with the objective to determine the historical sources of organic matter as well as the extent of its preservation. Effective molecular proxies were developed to differentiate the relative input of organic matter from different biological sources to wetland soils. Thus historical vegetation shifts and hydroperiods were reconstructed using those proxies. The data show good correlations with historical water management practices starting at the turn of the century and during the mid 1900’s. Overall, significant shortening of hydroperiods during this period was observed. The soil organic matter (SOM) preservation was assessed through elemental analysis and molecular characterizations of bulk 13C stable isotopes, solid state 13C NMR spectroscopy, UV-Vis spectroscopy, and tetramethyl ammonium hydroxide (TMAH) thermochemolysis-GC/MS. The relationship of the environmental conditions and degradation status of the soil organic matter (SOM) among the sites suggested that both high nutrient levels and long hydroperiod favor organic matter degradation in the soils. This is probably the result of an increase in the microbial activity in the soils which have higher nutrient levels, while longer hydroperiods may enhance physical/chemical degradation processes. The most significant transformations of biomass litter in this environment are controlled by very early physical/chemical processes and once the OM is incorporated into surface soils, the diagenetic change, even over extended periods of time is comparatively minimal, and SOM is relatively well preserved regardless of hydroperiod or nutrient levels. SOM accumulated in peat soils is more prone to continued degradation than the SOM in the marl soils. The latter is presumably stabilized early on through direct air exposure (oxidation) and thus, it is more refractory to further diagenetic transformations such as humification and aromatization reactions.

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Panthani, Matthew George. "Colloidal Nanocrystals with Near-infrared Optical Properties| Synthesis, Characterization, and Applications". Thesis, The University of Texas at Austin, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3572875.

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Colloidal nanocrystals with optical properties in the near-infrared (NIR) are of interest for many applications such as photovoltaic (PV) energy conversion, bioimaging, and therapeutics. For PVs and other electronic devices, challenges in using colloidal nanomaterials often deal with the surfaces. Because of the high surface-to-volume ratio of small nanocrystals, surfaces and interfaces play an enhanced role in the properties of nanocrystal films and devices.

Organic ligand-capped CuInSe₂ (CIS) and Cu(In_XGa_1-X)Se2 (CIGS) nanocrystals were synthesized and used as the absorber layer in prototype solar cells. By fabricating devices from spray-coated CuInSe nanocrystals under ambient conditions, solar-to-electric power conversion efficiencies as high as 3.1% were achieved. Many treatments of the nanocrystal films were explored. Although some treatments increased the conductivity of the nanocrystal films, the best devices were from untreated CIS films. By modifying the reaction chemistry, quantum-confined CuInSe_XS_2-X (CISS) nanocrystals were produced. The potential of the CISS nanocrystals for targeted bioimaging was demonstrated via oral delivery to mice and imaging of nanocrystal fluorescence.

The size-dependent photoluminescence of Si nanocrystals was measured. Si nanocrystals supported on graphene were characterized by conventional transmission electron microscopy and spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM). Enhanced imaging contrast and resolution was achieved by using Cs-corrected STEM with a graphene support. In addition, clear imaging of defects and the organic-inorganic interface was enabled by utilizing this technique.

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Zhang, Jin. "Electrodeposition of novel nanostructured and porous materials for advanced applications: synthesis, structural characterization and physical/chemical performance". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/393985.

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Aquesta tesi doctoral comprèn la síntesi electroquímica de materials metàl·lics avançats en dues configuracions diferents, capes poroses i nanofils segmentats. Les capes poroses s’han preparat per electrodeposició fent ús de les bombolles d’hidrogen que es generen durant el procés com a plantilles (sistemes de Ni i Cu-Ni macroporós) i també per electrodeposició en presència del polímer P123 que actua com a plantilla autoorganitzada (Ni nanoporós). Les capes de Cu-Ni presenten una porositat jeràrquica (estan formades per microporus esfèrics i les partes de porus són nanodendrítiques), caràcter superhidrofòbic i propietats ferromagnètiques a temperatura ambient (gràcies a la separació de fases que s’aconsegueix durant el procés de deposició). A més, aquestes capes són electroquímicament actives vers la reacció d’evolució d’hidrogen en medi alcalí, bo i presentant millor resposta que les capes de Cu i Ni poroses preparades en condicions similars. D’altra banda, s’han fabricat nanofils segmentats de CoPt/Cu/Ni i CoPt/Ni amb un control acurat de la llargada dels segments en membranes de policarbonat (PC). Gràcies al fet que els segments de CoPt i Ni presenten propietats ferromagnètiques distintes (l’un és magnèticament dur i l’altre magnèticament tou), es pot aconseguir un alineament antiparal·lel de la magnetització de saturació dels segments si llurs llargades es dissenyen de forma apropiada. Això faria possible minimitzar-ne la seva aglomeració un cop els nanofils fossin alliberats de la membrana de PC. Les troballes experimentals han estat validades mitjançant càlculs analítics. S’han utilitat les capes macroporoses de Cu-Ni i Ni com a matrius per a la fabricació de noves làmines de nanocompòsit, en particular ZnO@CuNi, Al2O3@Ni i Co2FeO4@Ni, mitjançat processos de sol-gel i deposició de capa atòmica (en anglès, ALD). L’ALD permet la formació d’un recobriment conformal de gruix nanomètric en l’esquelet metàl·lic porós. Els nanocompòsits resultants combinen les propietats de la matriu metàl·lica i les del recobriment (fotoluminescència i propietats fotocatalítiques en el cas del ZnO, canvis en la mullabilitat en el cas de Al2O3 i Co2FeO4). Finalment, s’han avaluat les propietats nanomecàniques de films de Ni nanoporós i s’ha vist que existeix una dependència tant del mòdul de Young com del límit d’elasticitat amb la força màxima aplicada durant els assaigs de nanoindentació, atès que aquetes capes presenten una gradació de la porositat en funció del gruix.
This Thesis dissertation covers the electrochemical synthesis of advanced metallic materials in two different configurations, namely porous films and segmented nanowires (NWs). Porous films are prepared by hydrogen bubble-assisted electrodeposition (macroporous Ni and Cu-Ni systems) and self-organized template (block-copolymer P123) assisted electrodeposition (nanoporous Ni). The Cu-Ni films exhibit a hierarchical porosity (they consist of micron-sized roughly spherical pores and nanodendritic walls), superhydrophobic character and ferromagnetic properties at room temperature (due to the occurrence of phase separation during deposition). Furthermore, they are electrocatalytically active toward hydrogen evolution reaction in alkaline media, outperforming pure Cu and Ni porous films prepared under similar conditions. Meanwhile, segmented CoPt/Cu/Ni and CoPt/Ni NWs with controlled segment lengths are prepared by electrodeposition in polycarbonate (PC) membranes. Due to the dissimilar ferromagnetic properties of CoPt and Ni segments (hard- and soft-ferromagnetic character, respectively), it is possible to achieve an antiparallel alignment of the magnetization of the segments if their lengths are properly tuned. This would make it possible to minimize aggregation of the NWs once released from the PC template. These findings have been validated by analytical calculations. The macroporous Cu-Ni and Ni films are used as scaffolds for the fabrication of novel nanocomposite layers, namely ZnO@CuNi, Al2O3@Ni and Co2FeO4@Ni, by applying sol-gel coating and atomic layer deposition techniques. The latter allows a nanometer-thick conformal coating of the metallic host. The resulting nanocomposites combine the properties coming from the metallic matrix and those arising from the coating (photoluminescence and photocatalytic properties in the case of ZnO, changes in the wettability for Al2O3 and Co2FeO4). Finally, the nanomechanical properties of nanoporous Ni films are evaluated and a thickness-dependence of both the Young’s modulus and the yield strength with the maximum applied force during nanoidentation is disclosed, due to the graded porosity of these films.

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Spencer, Matthew Todd. "New approaches for the chemical and physical characterization of aerosols using a single particle mass spectrometry based technique". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3264603.

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Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed August 2, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

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Buccella, Mauro. "Color masterbatches for polyamide 6 fibers. Optimization of compounding and spinning processes. Physical-chemical characterization of industrial products". Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368973.

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The objective of this work is the investigation of the industrial production process of the Color Masterbatches and of the parameters that influence the pigment dispersion into the polymer matrix. In particular, the project is focused on the production process optimization in order to increase the quality of the final product and to minimize their environmental impact.

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Buccella, Mauro. "Color masterbatches for polyamide 6 fibers. Optimization of compounding and spinning processes. Physical-chemical characterization of industrial products". Doctoral thesis, University of Trento, 2014. http://eprints-phd.biblio.unitn.it/1236/1/PhD_Thesis_-_Eprints_-_Mauro_Buccella.pdf.

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The objective of this work is the investigation of the industrial production process of the Color Masterbatches and of the parameters that influence the pigment dispersion into the polymer matrix. In particular, the project is focused on the production process optimization in order to increase the quality of the final product and to minimize their environmental impact.

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Richards, Paul. "Characterization of the electrical and physical properties of scandium nitride grown using hydride vapor phase epitaxy". Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4090.

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Roy, Choudhury Adarsh. "Defining Black: Characterization of Soot Reactivity with Thermogravimetrical Methods : Definiera svart: Karaktärisering av sotreaktivitet med termogravimetriska metoder". Thesis, KTH, Tillämpad fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-287478.

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Exhaust emissions in a vehicle has to flow through an exhaust aftertreatment in a diesel vehicle. In a diesel engine, the exhaust emissions are treated with Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), and Selective Catalytic Reduction (SCR). Every engine produces a different kind of soot depending on the drive cycle. In this thesis, a study was made on the soot oxidation in DPF so as to reduce the net fuel consumption and hence optimising the engine.This project focuses on DPF, where the soot and ash are trapped on the walls of the filter when the emissions flow through the DPF. Over a period of time, the soot accumulates and causes the pressure inside the filter to increase. To reduce the backpressure due to soot accumulation, soot has to be removed from the filter which is done by a regeneration process in which soot is oxidized. To understand the soot oxidation in the DPF, we study the chemical kinetics of the soot.The soot reacts with NO2, O2, and N2 in a Thermogravimetric Analysis (TGA) instrument, in isothermal conditions. Two soot samples, SORT-1 and FORCED 360 were analyzed with TGA, the rate equations were derived from using Arrhenius type kinetics and the data was processed by MATLAB. The rate at which the soot is oxidized by NO2 and O2 for SORT-1 is higher than for FORCED 360. This trend is observed similarly when both the soot samples react with only O2. When soot oxidation reaction takes place with O2 and NO2 they require a lower temperature of 250 °C-400 °C than compared to samples reacting with only O2 with a temperature of 350 °C - 500 °C. To understand the conditions that affect soot oxidation, the concentration of oxygen was varied and it was found that at higher oxygen concentration the soot oxidized is almost constant. Then soot kinetics were analysed by finding the rate of the reaction, the order of the reaction, and finally the activation energy. The order of the reaction for FORCED 360 and SORT-1 vary and slope of the graph, logarithm of reaction constant vs logarithm of mass shows a non-linearity in the former due to the slower rate of the reaction in SORT-1 than in FORCED 360. The activation energy was found to be 39.3 kJ/mol for SORT-1 and FORCED 360 is 60.8 kJ/mol.
Avgasutsläpp i ett fordon måste strömma genom avgasefterbehandling i ett dieselfordon. I en dieselmotor behandlas avgasutsläppen med dieseloxidationskatalysator (DOC), dieselpartikelfilter (DPF) och selektiv katalytisk reduktion (SCR). Varje motor producerar olika typer av sot beroende på körcykeln. I denna avhandling gjordes en undersökning av sotoxidationen i DPF för att minska nettobränsleförbrukningen och därmed optimera motorn. Detta projekt fokuserar på DPF, där sot och aska fångas på filterväggarna när utsläppen flyter genom dieselpartikelfiltret. Under en tidsperiod ackumuleras sot och får trycket inuti filtret att öka. För att minska mottrycket på grund av sotansamling måste sot avlägsnas från filtret, vilket görs genom en regenereringsprocess där sot oxideras. För att förstå sotoxidationen i DPF studerar vi sotens kemiska kinetik. Sotet reagerar med NO2, O2 och N2 i ett instrument för termogravimetrisk analys (TGA) under isotermiska förhållanden. Två sotprover, SORT-1 och FORCED 360 analyserades med TGA, hastighetsekvationerna härleddes från användning av Arrhenius-typskinetik och data bearbetades av MATLAB. Den hastighet med vilken sot oxideras av NO2 och O2 för SORT-1 är högre än för FORCED 360. Denna trend observeras på liknande sätt när båda sotproverna reagerar med endast O2. När reaktion genom sotoxidation äger rum med O2 och NO2 kräver de en lägre temperatur på 250 ° C - 400 ° C än jämfört med prover som bara reagerar med O2 med en temperatur på 350 ° C - 500 ° C. För att förstå de förhållanden som påverkar sotoxidation varierades syrekoncentrationen och det visade sig att vid högre syrekoncentration var sotet oxiderat nästan konstant. Därefter analyserades sotkinetiken genom att hitta reaktionshastigheten, reaktionsordningen och slutligen aktiveringsenergin. Reaktionsordningen för FORCED 360 och SORT-1 varierar och lutningen i diagrammet, logaritmen för reaktionskonstanten mot logaritmen av massan visar en icke-linjäritet i den tidigare på grund av den långsammare reaktionshastigheten i SORT-1 än i FORCED 360. Aktiveringsenergin konstaterades vara 39,3 kJ / mol för SORT-1 och för FORCED 360, 60,8 kJ / mol.

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Ruiz-Córdova, Sergio S. Webber Elliott Clifford Bayne David Roberge. "Physical-chemical and biological characterization of small streams following intensive forest management practices in the coastal plain of Alabama". Auburn, Ala., 2007. http://repo.lib.auburn.edu/EtdRoot/2007/FALL/Fisheries_and_Allied_Aquacultures/Thesis/Ruiz-cordova_Sergio_36.pdf.

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Unsal, Emre. "Integrated Real Time Studies to Track all Physical and Chemical Changes in Polyimide Film Processing From Casting to Imidization". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1384129535.

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Mitchell, Beth Louise. "Characterization of the Physical, Chemical, and Biological Factors that Control the Fate and Transport of Bacteria through Glacial-Outwash Sediments". Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1164820103.

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Dusek, Ulrike. "Characterization of marine boundary layer aerosol from north Atlantic and European sources : physical and chemical properties and climate forcing parameters /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/10065.

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Arroyo, Molina Javier. "Towards a virtual climate chamber – A physical experimental study". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282848.

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This project focuses on experimentally characterizing one of the tools used at Ericsson AB to test product performance, the climatic chamber. By conducting experiments inside the climate chamber and post processing the data obtained, the airflow inside it can be understood and compared to outdoor experimental data. One of the main sections of this work is to prove the hypothesis: The energy potential of the wind outdoors is greater than indoors, which is shown to be true when comparing values for the integral length scales of the flow, at the same mean wind speed. The second main part of this project is to obtain valuable experimental input that will serve to construct a virtual model of the climate chamber. With the conclusions drawn from the experiments, which involve heat transfer, boundary conditions for the numerical model can be established.
Det här projektet fokuserar på att experimentellt karakterisera ett av verktygen som används i Ericsson AB för att testa produktprestanda - klimatkammaren. Genom att utföra experiment inuti klimatkammaren och efterbehandla de erhållna data, kan man få en förståelse för luftflödet inuti kammaren och jämföra resultat med experimentella data från utomhus. Ett av delmomenten i detta arbete bevisar hypotesen: 'Vindens energipotential är större än inomhus', vilket visar sig vara sant när man jämför värden för flödets integrala längdskalor, med samma medelvärde i vindhastighet. Den andra etappen av detta projekt är att erhålla en värdefull experimentell vägledning som kommer att tjäna till att konstruera en virtuell modell av klimatkammaren. Med slutsatserna från experimenten, som innefattar värmeöverföring, kan gränsvillkor för den numeriska modellen fastställas.

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Teses / dissertações sobre o tema "Physical and chemical characterizations"

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