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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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Fracasso, Guido <1960>. "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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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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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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Vereš, Ján, Štefan Jakabský, and 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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Vereš, Ján, Štefan Jakabský, and 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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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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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 JANEIROCOORDENAÇÃO 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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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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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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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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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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Marchetti, Marco <1980>. "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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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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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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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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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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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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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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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(InXGa 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 XS2-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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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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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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Merkel, Marcel Patrick [Verfasser], and 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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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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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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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, 2015There 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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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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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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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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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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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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Diesch, Jovana-Maria [Verfasser]. "Stationary in-situ measurements of aerosols, gaseous pollutants and meteorology : chemical and physical characterization of natural and anthropogenic sources / Jovana-Maria Diesch." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1051349524/34.
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Ab, Rani Mohd Azri. "Synthesis, characterization and physical-chemical properties of room temperature ionic liquids with a variety of cations, paired with bis(trifluoromethylsulfonyl)imide anion." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/10475.
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This thesis contains two main parts: synthesis of ionic liquids and their precursors, and measurement of the physical-chemical properties of the ionic liquids synthesized. The first part describes a study of the successful synthesis of 22 ionic liquids and their precursors, including 12 novel compounds ([RC1im][X] and [RC1pyrr][X] where R=C4, C5, C2OC2C1, SiOSiC1, (SiO)2SiC1, X=Cl, NTf2). In this study a reliable and rigorous method for the synthesis of ionic liquids in a good yield and high quality was developed. The ionic liquids synthesized contained a variety of cations containing alkyl, ether, disiloxane and trisiloxane side chains. All the ionic liquids contained the bis(trifluoromethylsulfonyl) imide anion. The second part of the project was the study of the physical-chemical properties of the ionic liquids synthesized. Understanding these physical-chemical properties is required before any applications can proceed. The polarity, density, thermal stability, viscosity, conductivity and diffusion coefficients of the ionic liquids were measured and described. The Kamlet-Taft [Symbol appears here. To view, please open pdf attachment] values of the ionic liquids are dominated by the nature of cations whereas the β values are controlled by the nature of the anion. The polarizability values, π* were lowered by having siloxane side chains in comparison to alkyl and ether side chains. Ionic liquids with an ether side chain showed the highest density of those studied. The thermal stabilities of the ionic liquids followed the order alkane > ether > disiloxane > trisiloxane substituent. From a transport property point of view, it can be concluded that the less viscous the ionic liquids, the faster the movement and higher the diffusion coefficient of the ions.
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Erdog, Asli. "Characterization Of Liposomal Celecoxib Formulation As A Drug Delivery System In Colorectal Cancer Cell Lines." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614271/index.pdf.
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Colorectal carcinoma (CRC) is one of the most common cancers and is the leading
cause of cancer deaths in much of the developed world. Owing to the high
incidence of drug resistance and potential toxic effects of chemotherapy drugs,
much research is currently underway to design better strategies for smart drug
delivery systems. Cyclooxygenase-2 (COX-2) pathway is associated with poor
prognosis in colon carcinomas. The selective COX-2 inhibitor drug Celecoxib
(CLX) has been shown to posses COX-2 independent anti-carcinogenic effects in
addition to inhibition of prostaglandins synthesis. The aim of the presented thesis
was to develop a liposomal delivery system for CLX and to evaluate functional
effects in CRC cell lines. Starting with multilamellar vesicles capable of CLX
encapsulation and retention, nano sized liposomes were prepared and characterized
in vitro. The optimum composition was determined as 10:1 DSPC: Cholesterol molar ratio and Polyethylene glycol (PEG) grafting at 2% of phospholipids. The
extent of cellular association of PEGylated liposome formulation was analyzed
quantitatively and cellular localization was analyzed qualitatively. We detected that
CLX loaded PEGylated liposomes inhibited proliferation and cellular motility of
cancer cells in a 2D model system. Our results showed that, Epidermal Growth
Factor Receptor (EGFR) targeted CLX loaded immunoliposomes were extremely
cytotoxic in cancer cells with high EGFR expression but not in cells devoid of
EGFR expression. This delivery system may pioneer studies that may potentially
circumvent the harmful systemic side effects of cancer preventive and
chemotherapy drugs as well as allow the use of targeted combinatorial therapies.
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Olsen, Aric Alan. "Discharge Monitoring, Chemical Characterization, and Source Identification of Springs Along the East Side of Southern Cache Valley, Utah." DigitalCommons@USU, 2007. https://digitalcommons.usu.edu/etd/6760.
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Discharge monitoring and water sampling of springs in the southeastern portion of Cache Valley, Utah was performed in order to determine recharge sources and the cause of decreasing flows for some springs. The discharges of 43 springs were measured monthly from May or June of 2005 through March of 2006. Water samples from 36 of these springs plus an additional 10 were analyzed for major ions and trace metals. Twenty-one of the springs were analyzed for deuterium and oxygen-18 and 10 of these were analyzed for tritium. The springs were divided into groups based on when they had their peak discharge. Peak discharges in the summer months suggest recharge from excess irrigation water and/or canal water, whereas peak discharges in winter months suggest recharge from rivers, and peak discharges in spring months suggest recharge by precipitation and/or river water recharge. Multiple discharge peaks suggest multiple recharge sources. The chemical data collected in the study were compared with data from previous investigations to determine potential spring sources, including: shallow ground water, deep ground water, irrigation (river/canal) water, and precipitation. Spring water is characterized by calcium, magnesium, and bicarbonate, similar to deep ground water and river water. However, most of the 21 springs analyzed for deuterium and oxygen-18 displayed an evaporative signature; thus, chemically, the shallow, unconfined aquifer that recharges these springs appears to be recharged in part by excess irrigation water and/or canal water. Several of the springs have high chloride levels indicating the shallow, unconfined aquifer recharging those springs has surface runoff infiltrating into it. Because of the evaporative signature in the stable isotopes, the similarity of major ion and trace metal values, and the discharge trends observed throughout the year, it seems unlikely that the springs are directly connected hydraulically with the deep, confined aquifer, from which most of the wells in the valley withdraw their water. Thus, the recent drought, rather than increased pumping, probably has been responsible for decreases in spring discharges.
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Semprini, Simone. "Mechanical and chemical-physical characterization of sandstone from the Phoenician-Punic necropolis of Tharros (Sardinia, Italy) with the aim of its conservation and strengthening." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
The archaeological site of Tharros, located in the province of Oristano in Sardinia, annually hosts about 106,000 visitors.
The site consists of an archaeological area already accessible by tourists and a Punic necropolis object of excavations for several decades, which has brought to light archaeological artifact of great cultural value. To fully exploit the archaeological site of Tharros, the necropolis should be at the disposal of the tourist interest. For this reason, the idea of a conservation project arose, aimed at making this area of the site accessible.
The study derives from the need to improve the knowledge about the characteristics of the sandstone in which the necropolis is carved, as such sandstone suffers from structural problems and natural weathering.
In DICAM Laboratories, in Bologna, mechanical characterization tests were performed to identify the compressive and tensile strength of the stone. Preliminary fracture mechanics tests were also carried out. Regarding the chemical-physical characterization, capillarity absorption test, X-ray diffraction (XRD), Ion Chromatography, Mercury Intrusion Porosimetry (MIP) and Calcimetry test were performed.
Finally, a study on the effectiveness of ethyl silicate consolidant (TEOS) on Tharros sandstone was carried out, in terms of mechanical properties and colour variation.
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Hewage, Dilrukshi C. "SPECTROSCOPIC CHARACTERIZATION OF LANTHANUM-MEDIATED HYDROCARBON ACTIVATION." UKnowledge, 2015. http://uknowledge.uky.edu/chemistry_etds/54.
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Lanthanum (La)-promoted hydrocarbon activation reactions were carried out in a laser vaporization metal cluster beam source. Reaction products were identified by time-of-flight mass spectrometry, and the approximate ionization thresholds of La-hydrocarbon complexes were located with photoionization efficiency spectroscopy. The accurate ionization energies and vibrational frequencies of the La complexes were measured using mass analyzed threshold ionization (MATI) spectroscopy. Their molecular structures and electronic states were investigated by combing the MATI spectroscopic measurements with quantum chemical and Franck-Condon factor calculations.
In this dissertation, La-mediated C-H and C-C bond activation reactions were investigated for several small alkynes (acetylene, propyne) and alkenes (propene, 1,3-butadiene, 1-butene). The C-H bond activation was observed for both alkynes and alkenes and the C-C bond activation for alkenes. The metal-hydrocarbon intermediates formed by the C-H or C-C bond cleavage reacted further with one or more parent hydrocarbon molecules to produce larger species by C-C bond coupling reactions. Structural isomers of the intermediates and products were identified within an energy range of several kilocalories per mole. Reaction pathways for the intermediate and product formations were studied by theoretical calculations.
The ground electron configuration of La atom is 4d16s2.Upon the hydrocarbon coordination, La atom is excited to a 4d26s1 configuration to facilitate the formation of two La-C bonds. After the metal-hydrocarbon complex formation, only one electron is left in the 6s orbital of the metal center. Therefore, the most stable electronic state of the La complexes studied in this work is in a doublet spin state. Ionization of the doublet state yields a preferred singlet ion state. Although La is in the formal oxidation state of +2, the ionization energies of the metal-complexes are significantly lower than that of the free atom. This observation suggests that the concept of the formal oxidation state widely used in chemistry textbooks is not useful in predicting the change of the ionization energy of a metal atom upon ligation. Moreover, ionization has a very small effect on the geometry of the hydrocarbon fragment in each complex but significantly reduces the La-C distances as a result of an additional charge interaction.
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Sayin, Esen. "In-vitro Characterization Of A Novel Cdte-cds/2mpa-dmsa Quantum Dot." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613629/index.pdf.
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Quantum dots (QDs) are increasingly attracting attention in recent years due to their potential in biological imaging and drug delivery applications. Despite their significant advantages over organic dyes and fluorescent proteins, cytotoxicity is still a major problem in live-cell QD labeling.
In this work, in-vitro characterization of a novel CdTe/2MPA quantum dot capped with CdS-DMSA was conducted on human cervical cancer (HeLa) and mouse fibroblast (NIH/3T3) cell lines. Biocompatibility of this novel particle was evaluated in comparison to a commercial quantum dot (Qdot 565) and various QDs with CdTe core.
Cytotoxicity of quantum dots was investigated using XTT and proliferation assays. Cellular internalization and localization of particles were studied using confocal laser scanning microscopy. For quantitative determination of internalization and intracellular QD stability, we also performed uptake and cadmium release assays.
Optimal cell imaging concentration with CdTe-CdS/2MPA-DMSA was determined as 10-50 ug/mL in HeLa cells. Localization of the internalized QD particles was observed in the perinuclear region of the cells. XTT and proliferation assays provided identical viability results for the tested QDs. CdS-DMSA capping increased cytocompatibility of CdTe/2MPA by 15% in NIH/3T3 cells. Biocompatibility of this capped particle was further increased by 3-folds
with pegylation. For pegylated CdTe-CdS/2MPA-DMSA and commercial Qdot 565, we have not observed QD-related cytotoxicity on NIH/3T3 cells following
24-hr QD exposure at 50 ug/mL. Our in-vitro characterization studies indicate that CdTe-CdS/2MPA-DMSA is a promising live-cell imaging probe which can be effectively excited in the visible range of the electromagnetic spectrum.
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Silva, Mariane Capellari Leite da. "Caracterização físico-química de SiC sintetizado pelo processo Acheson a partir de diferentes fontes de SiO2." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-06052015-165740/.
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Atualmente, há uma forte demanda por cerâmicas como materiais estruturais para substituição de metais e ligas de elevada dureza e para uso em ambientes hostis. Dentre as famílias das cerâmicas estruturais, o SiC se destaca devido ao seu conjunto de propriedades: alta resistência à oxidação/corrosão, elevada resistência à abrasão, elevada condutividade térmica, baixa massa específica, elevada dureza, boa resistência ao choque térmico e manutenção da maioria destas propriedades em temperaturas elevadas. O processo Acheson se caracteriza, industrialmente, como o principal processo de síntese do SiC, consistindo em dois eletrodos sólidos, conectados a pó de grafite compactado, circundados por uma mistura de sílica e coque, em que o aquecimento é realizado eletricamente entre temperaturas de 2200 a 2600 oC [SOMIYA, 1991]. A formação do SiC é dependente da pressão parcial dos gases, da temperatura, do tamanho de grão dos reagentes, das propriedades individuais de cada grão, assim como da área de contato e do grau de mistura entre SiO2 e C [LINDSTAD, 2002]. O SiC produzido pelo processo Acheson contém impurezas como Al, Fe, Ti, Na, provindas da matéria-prima, que durante a síntese têm seu comportamento influenciado pela variação de temperatura. Partículas metálicas ou carbetos dessas impurezas estão distribuídos na matriz de SiC, sendo encontrados à medida que a temperatura diminui, com exceção do Al que se encontra em solução sólida com o SiC, substituindo os átomos de Si na rede cristalina [WEIMER, 1997]. Os objetivos deste trabalho se concentraram na caracterização e avaliação da influência da matéria-prima e das condições de processo no SiC obtido pelo processo Acheson. Podendo-se observar, através das análises químicas, mineralógicas e microestruturais, que a distribuição das impurezas, ao longo da secção transversal do SiC, é independente da matéria-prima precursora, sendo que estas se concentram nas regiões mais distantes do núcleo de grafite, porém seus teores são superiores para o SiC sintetizado a partir de uma matéria-prima menos pura, as quais ainda apresentaram temperatura de início do processo de oxidação do SiC pelo menos 50 oC menor, quando comparado ao SiC sinterizados a partir de matérias-primas com maior grau de pureza.Currently, there is a strong demand for ceramics as structural materials to replace metals and alloys with high hardness for use in hostile environments. Among structural ceramics families, silicon carbide stands out due to its unique properties combination: high corrosion/oxidation resistance, high abrasion resistance, low density, high hardness, high thermal conductivity, good thermal shock resistance and maintenance of the majority of these properties at elevated temperatures. The Acheson process is industrially the main synthesis process of silicon carbide, consisting of two solid electrodes connected to compacted graphite powder, surrounded by a mixture of silica and petroleum coke, wherein the heating is performed electrically between 2200 to 2600 oC [SOMIYA, 1991]. The formation of SiC depends on the partial pressure of gases, temperature, reactants grain size, the properties of each individual grain as well as the contact area and the degree of mixing between SiO2 and C [LIDSTAD, 2002]. The SiC produced by the Acheson process contains impurities from the raw materials, such as Al, Fe, Ti and Na, which during the synthesis are influenced by the temperature gradient. Metal or carbides particles of these impurities are distributed in SiC matrix, being found as the temperature decreases, with exception of Al that forms solid solution with SiC by replacing the Si atoms in the crystal lattice [WEIMER, 1997]. The objectives of this work was the characterization and evaluation of the influence of raw materials and process conditions on the behavior of silicon carbide synthesized by Acheson process. It was observed, through chemical, mineralogical and microstructural analyzes, that the distribution of impurities along the cross section of synthesized SiC is independent of the raw material precursor, and these are concentrated in the most distant regions of the graphite core, but its contents are superior to SiC synthesized from a less pure raw material, which also showed a change in the beginning of the SiC oxidation process, at least 50 ° C lower, than the synthesized SiC from raw material with higher purity.
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Carlegrim, Elin. "Preparation and characterization of an organic-based magnet." Licentiate thesis, Norrköping : Department of Science and Technology, Linköping University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10426.
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Amouroux, Julien. "Procédé de croissance et caractérisation avancée de nanocristaux de silicium pour une intégration dans les mémoires non-volatiles." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4766/document.
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De par leurs performances et leur fiabilité, la technologie Flash constitue, à l'heure actuelle, la référence en matière de mémoire non volatile. Cependant, ces mémoires étant en passe d'atteindre leurs limites de miniaturisation, plusieurs dispositifs alternatifs sont actuellement envisagés par les industriels du secteur, de manière à anticiper les demandes du marché ces prochaines années.Depuis 2003, des études ont été menées sur le remplacement de la grille flottante en silicium polycristallin des mémoires Flash par des nanocristaux. La modication du flot de procédés d'une mémoire à nanocristaux permet une réduction des coûts de fabrication, une amélioration de la fiabilité et une miniaturisation des dispositifs. L'intégration des nanocristaux dans une cellule mémoire de type Flash constitue donc un challenge pour l'industrie afin de repousser les limites de miniaturisation de cette architecture mémoire basée sur le transistor MOS, dispositif historique de l'industrie des semiconducteurs.Ce manuscrit présente les résultats de ma thèse qui porte sur les procédés de croissance de nanocristaux de silicium et leur caractérisation morphologique en vue d'une intégration dans des mémoires non volatiles.Les objectifs de la thèse sont :- Le transfert du procédé de fabrication des nanocristaux de silicium du CEA LETI vers l'usine de STMicroelectronics à Rousset ;- L'intégration des nanocristaux dans une cellule mémoire non-volatile ;- L'optimisation des procédés de fabrication en vue d'une industrialisation ;- Le développement d'outils de caractérisation de la chaîne de procédés ;- L'étude physique et physico-chimique avancée des nanocristaux de siliciumBy their performance and reliability, Flash technology is, today, the reference in nonvolatile memory . However, these memories being on track to reach their miniaturization limits , several alternative devices are currently being considered by the industrial sector, to anticipate market demands in the coming years .Since 2003, studies have been conducted on the replacement of the polysilicon floating gate by silicon nanocrystals in flash memory with nanocrystals to sustain this memory technology memory. Process flow modifications for nanocrystal integration allows a reduction of manufacturing costs, improving of reliability and miniaturization of devices . Integration of nanocrystals in a flash-like memory cell is therefore a challenge for the industry to extend the limits of miniaturization of the memory architecture based on the MOS transistor, historical device of the semiconductor industry.This manuscript presents the results of my thesis on the silicon nanocrystals growth process and morphological characterization for integration in a nonvolatile memory. The objectives of the thesis are :- Transfer of the manufacturing process of the silicon nanocrystals growth from CEA LETI plant to STMicroelectronics Rousset ;- Integration of nanocrystals in a non-volatile memory cell;- Optimization of manufacturing processes for industrialization ;- Development of tools to characterize the process chain ;- Physical and physico-chemical study of advanced silicon nanocrystals . and morphological characterization for integration in a nonvolatile memory
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Werner, Katharina [Verfasser], and Wolfgang [Akademischer Betreuer] Stolz. "Chemical vapor deposition and physical characterization of gallium, and carbon-related structures on Si (001) and GaP/Si (001) templates for the growth of graphene layers / Katharina Werner. Betreuer: Wolfgang Stolz." Marburg : Philipps-Universität Marburg, 2015. http://d-nb.info/1080298444/34.
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Ambati, Jyotrhirmai. "STUDIES ON SILICON NMR CHARACTERIZATION AND KINETIC MODELING OF THE STRUCTURAL EVOLUTION OF SILOXANE-BASED MATERIALS AND THEIR APPLICATIONS IN DRUG DELIVERY AND ADSORPTION." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/203.
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This dissertation presents studies of the synthetic processes and applications of siloxane-based materials. Kinetic investigations of bridged organoalkoxysilanes that are precursors to organic-inorganic hybrid polysilsesquioxanes are a primary focus. Quick gelation despite extensive cyclization is found during the polymerization of bridged silane precursors except for silanes with certain short bridges. This work is an attempt to characterize and understand some of the distinct features of bridged silanes using experimental characterization, kinetic modeling and simulation. In addition to this, the dissertation shows how the properties of siloxane- materials can be engineered for drug delivery and adsorption.
The phase behavior of polymerizing mixtures is first investigated to identify the solutions that favor kinetic characterization. Microphase separation is found to cause gradual loss of NMR signal for certain initial compositions. Distortionless Enhancement by Polarization Transfer 29Si NMR is employed to identify the products of polymerization of some short-bridged silanes under no signal loss conditions. This technique requires knowing indirect 29Si-1H scalar coupling constants which sometimes cannot be measured due to second-order effects. However, the B3LYP density functional method with 6-31G basis set is found to predict accurate 29Si-1H coupling constants of organoalkoxysilanes and siloxanes. The scalar coupling constants thus estimated are employed to resolve non-trivial coupled NMR spectra and quantitative kinetic modeling is performed using the DEPT Si NMR transients. In order to investigate the role of the organic bridging group, the structural evolution of bridged and non-bridged silanes are compared using Monte Carlo simulations. Kinetic and simulation models suggest that cyclization plays a key role right from the onset of polymerization for bridged silanes even more than in non-bridged silanes. The simulations indicate that the carbosiloxane rings formed from short-bridged precursors slow down but do not prevent gelation.
The tuning of siloxane-based materials for adsorption technologies are also discussed here. In the first example, antioxidant enzyme loading is investigated as a means to reduce oxidative stress generated by silica nanoparticle drug carriers. Materials are engineered for promising enzyme loading and protection from proteolysis. Second, the potential of copper sulfate impregnation to enhance adsorption of ammonia by silica is explored by molecular simulation.
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Kokubo, Shinsuke [Verfasser], Philipp [Akademischer Betreuer] Vana, Philipp [Gutachter] Vana, Konrad [Gutachter] Koszinowski, Martin [Gutachter] Suhm, Michael [Gutachter] Buback, Ricardo [Gutachter] Mata, and Florian [Gutachter] Ehlers. "Characterization of Physical and Chemical Properties of Synthetic Polymer using Ion Mobility-Mass Spectrometry / Shinsuke Kokubo ; Gutachter: Philipp Vana, Konrad Koszinowski, Martin Suhm, Michael Buback, Ricardo Mata, Florian Ehlers ; Betreuer: Philipp Vana." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1149959371/34.
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Kokubo, Shinsuke Verfasser], Philipp [Akademischer Betreuer] Vana, Philipp [Gutachter] Vana, Konrad [Gutachter] Koszinowski, Martin [Gutachter] Suhm, Michael [Gutachter] [Buback, Ricardo [Gutachter] Mata, and Florian [Gutachter] Ehlers. "Characterization of Physical and Chemical Properties of Synthetic Polymer using Ion Mobility-Mass Spectrometry / Shinsuke Kokubo ; Gutachter: Philipp Vana, Konrad Koszinowski, Martin Suhm, Michael Buback, Ricardo Mata, Florian Ehlers ; Betreuer: Philipp Vana." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:7-11858/00-1735-0000-0023-3FAC-5-6.
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Ciprandi, Alana. "Caracterização físico-química do leite normal e do leite instável não ácido (LINA)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/115198.
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O objetivo do presente trabalho foi determinar a ocorrência de leite instável não ácido (LINA), e as características físico-químicas do leite com diferentes graus de estabilidade ao etanol. As coletas foram realizadas no período de janeiro a março de 2013, em um laticínio localizado ao norte do Estado do Rio Grande do Sul. Coletou-se um total de 651 amostras de leite cru, diretamente dos reservatórios dos caminhões na plataforma de recebimento na indústria. As amostras foram armazenadas em temperatura de refrigeração, e foram analisadas em no máximo 6 horas. Foi determinada a composição centesimal das amostras e em seguida, estas foram submetidas às análises físico-químicas de estabilidade ao etanol, pH, capacidade de tamponamento, acidez titulável, fervura e crioscopia. Os resultados obtidos foram utilizados para avaliar as diferenças entre Leite Instável Não-Ácido (LINA) e leite normal, após a estratificação das amostras de leite em dois grupos: LINA (instável ao etanol 72°GL com acidez titulável entre 14 e 18°D) e leite normal (estável na presença de etanol 72°GL e acidez entre 14 e 18°D). As amostras que não se enquadraram nestes 2 grupos foram desconsideradas. Das 592 amostras analisadas, 361 (60,98%) foram classificadas como LINA e 231 (39,02%) como leite normal. Para avaliar o leite com diferentes graus de estabilidade ao etanol, as amostras foram estratificadas em três categorias (estável ao álcool com concentração igual ou menor que 70°GL; entre 72 e 76°GL; e maior que 78°GL). Para ambas as estratificações das amostras, os parâmetros físico-químicos foram testados estatisticamente pelo teste de Kruskal-Wallis, o qual indica se há diferenças estatísticas nos resultados de cada análise entre os grupos. Com os resultados obtidos pode-se concluir que a incidência de LINA na região é elevada (60,97%); e que este leite apresentou estabilidade no teste de fervura, provando a ineficiência de se utilizar somente o teste do etanol para prever a estabilidade térmica das proteínas. Os valores de temperatura e acidez foram maiores em leites instáveis, já a estabilidade ao etanol e o pH se mostrou maior em leites mais estáveis. A capacidade de tamponamento não se mostrou diferente entre os grupos. A composição de sólidos foi maior em leites instáveis, com maior teor de ESD, gordura e proteína. As porções de lactose e os resultados de crioscopia, não apresentaram diferença significativa entre os estratos.The objective of this study was to determine the occurrence and the physicochemical characteristics of milk with different stabilities to ethanol . The collections were made in the period of January to March 2013 in a dairy located in the north of the State of Rio Grande do Sul. It was collected from a total of 651 samples of raw milk (about 150 ml of milk each sample) , which were collected directly from the tanks of trucks on the receiving platform in the industry . The samples were stored at refrigerator temperature and analyzed in the maximum of 6 hours from the collection. The proximate composition of the samples was determined and then they were subjected to the following physico-chemical analysis : stability to ethanol , pH , buffering capacity, titratable acidity , boiling and freezing point.The results were used to: (1) to assess the differences between unstable non-acid milk (UNAM), normal milk , and when the milk samples were stratified into two groups: UNAM ( clot by mixing equal amount of 72° GL ethanol and milk and titratable acidity between 14 and 18 ° D ) and regular milk ( stable in the presence of ethanol and acidity between 14 and 18 ° D ). The remaining samples not classified in these 2 groups were disregarded. Of the 592 samples analyzed, 361 (60.98%) were classified as UNAM and 231 (39.02%) as normal milk. For stability tests to ethanol , pH and acidity and fat, protein and solids nonfat , a significant difference ( p < 0.05 ) was found by Kruskal wallis test between UNAM and normal milk, with UNAM presenting the higher values There was no difference (p > 0.05) for the buffering capacity, freezing point and the amount of lactose. From the obtained results it can be concluded that the incidence of UNAM in the region is high, and that this milk was stable in the boiling test, proving the inefficiency of using only this test to predict the thermal stability of proteins. (2) evaluate the milk differences degrees of stability to ethanol. Milk samples were stratified with respect to the stability of the ethanol in 3 categories (stable to alcohol with concentration equal to or smaller than 70 ° GL , between 72 and 76° GL and greater than 78° GL). Of the total samples tested , 398 (61.14%) samples proved unstable at 72 ° GL alcohol and of these, 6 had acidity above 18°D , making in this way , 392 (60.21%) milk samples characterized as unstable no acid (UNAM). By Kruskal-Wallis test , titratable acidity, pH and temperature on reception showed significant differences (p < 0.05) between groups 1 against groups 2 and 3, the amount of fat , protein and solids nonfat varied significantly between all groups (p <0.05 ), whereas there was no such difference in buffering capacity. Lactose and cryoscopic index were considered statistically equal between groups 1 and 2 (p > 0.05) and different for group 3 (p < 0.05). With the results, we can conclude that there is a high incidence of UNAM in the region studied and that this milk showed no coagulation test in boiling , demonstrating the inefficiency of this test as an indicator of thermal stability.
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Silva, Sandra Lopes da. "NMR in the characterization of heavy residual procedural streams." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13126.
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Doutoramento em QuímicaThe main objective of this work was to monitor a set of physical-chemical properties of heavy oil procedural streams through nuclear magnetic resonance spectroscopy, in order to propose an analysis procedure and online data processing for process control. Different statistical methods which allow to relate the results obtained by nuclear magnetic resonance spectroscopy with the results obtained by the conventional standard methods during the characterization of the different streams, have been implemented in order to develop models for predicting these same properties. The real-time knowledge of these physical-chemical properties of petroleum fractions is very important for enhancing refinery operations, ensuring technically, economically and environmentally proper refinery operations. The first part of this work involved the determination of many physical-chemical properties, at Matosinhos refinery, by following some standard methods important to evaluate and characterize light vacuum gas oil, heavy vacuum gas oil and fuel oil fractions. Kinematic viscosity, density, sulfur content, flash point, carbon residue, P-value and atmospheric and vacuum distillations were the properties analysed. Besides the analysis by using the standard methods, the same samples were analysed by nuclear magnetic resonance spectroscopy. The second part of this work was related to the application of multivariate statistical methods, which correlate the physical-chemical properties with the quantitative information acquired by nuclear magnetic resonance spectroscopy. Several methods were applied, including principal component analysis, principal component regression, partial least squares and artificial neural networks. Principal component analysis was used to reduce the number of predictive variables and to transform them into new variables, the principal components. These principal components were used as inputs of the principal component regression and artificial neural networks models. For the partial least squares model, the original data was used as input. Taking into account the performance of the develop models, by analysing selected statistical performance indexes, it was possible to conclude that principal component regression lead to worse performances. When applying the partial least squares and artificial neural networks models better results were achieved. However, it was with the artificial neural networks model that better predictions were obtained for almost of the properties analysed. With reference to the results obtained, it was possible to conclude that nuclear magnetic resonance spectroscopy combined with multivariate statistical methods can be used to predict physical-chemical properties of petroleum fractions. It has been shown that this technique can be considered a potential alternative to the conventional standard methods having obtained very promising results.
O principal objetivo deste trabalho foi monitorizar um conjunto de propriedades físico-químicas de correntes processuais pesadas através da espectroscopia de ressonância magnética nuclear, com o intuito de propor um procedimento de análise e processamento de dados em linha para o controlo processual. Vários métodos estatísticos que permitiram relacionar os resultados obtidos por espectroscopia de ressonância magnética nuclear com os resultados obtidos pelos métodos convencionais, aquando da caracterização das diferentes correntes, foram implementados a fim de desenvolver modelos de previsão dessas mesmas propriedades. O conhecimento em tempo real das propriedades físico-químicas dos derivados de petróleo é essencial para otimizar as operações de refinação, garantindo assim operações técnica, económica e ambientalmente adequadas. A primeira parte deste trabalho envolveu a realização de um elevado número de experiências, efetuadas na refinaria de Matosinhos, seguindo métodos convencionais normalizados, importantes para avaliar e caracterizar as correntes de gasóleo de vácuo leve, gasóleo de vácuo pesado e fuel óleo. As propriedades analisadas foram a massa volúmica, viscosidade cinemática, teor em enxofre, ponto de inflamação, resíduo carbonoso, valor P e a destilação atmosférica e de vácuo. Para além da determinação de todas estas propriedades físico-químicas, usando os métodos convencionais, as mesmas amostras foram analisadas por espectroscopia de ressonância magnética nuclear. A segunda parte deste trabalho esteve relacionada com a aplicação de métodos estatísticos multivariáveis que relacionam as propriedades físico-químicas com a informação quantitativa adquirida por espectroscopia de ressonância magnética nuclear. Vários métodos foram aplicados, incluindo a análise por componentes principais, a regressão múltipla por componentes principais, as regressões múltiplas parciais e as redes neuronais artificiais. A análise de componentes principais foi utilizada para reduzir o número de variáveis preditivas e transformá-las em novas variáveis, os componentes principais. Estes componentes principais foram utilizados como variáveis de entrada da regressão múltipla por componentes principais e das redes neuronais artificiais. Na regressão por mínimos quadrados parciais os dados originais foram usados como variáveis de entrada. Tomando em consideração o desempenho dos modelos desenvolvidos, com recurso a parâmetros estatísticos, foi possível concluir que a regressão múltipla por componentes principais contribuiu para piores desempenhos. Melhores desempenhos foram obtidos com a aplicação da regressão por mínimos quadrados parciais e das redes neuronais artificiais. No entanto, foi com os modelos de redes neuronais artificiais que melhores desempenhos foram obtidos em quase todas as propriedades analisadas. Tendo em conta os resultados obtidos, foi possível concluir que a espectroscopia de ressonância magnética nuclear combinada com métodos estatísticos multivariáveis pode ser usada para prever as propriedades físico-químicas de derivados de petróleo. Demonstrou-se que esta técnica pode ser considerada como uma potencial alternativa aos métodos convencionais tendo-se obtido resultados bastantes promissores.
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Sonja, Ivković. "Novi kompleksi nekih 3d metala sa semi-, tiosemi- i S-metilizotiosemikarbazonom piridoksala." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2014. https://www.cris.uns.ac.rs/record.jsf?recordId=85689&source=NDLTD&language=en.
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Opisane su sinteze, fizičko-hemijske i strukturne karakteristike kompleksa Cu(II), Co(II), Co(III), Ni(II), Fe(III), Cr(III) Zn(II) i Cd(II) sa PLSC, PLTSC i PLITSC. Dobijene su dve nove protonovane forme liganda PLSC, kao i od ranije poznati neutralna forma PLSC i protonovana forma PLTSC ali u vidu monokristala pogodnih za rentgeno-strukturnu analizu i 37 kompleksa, od čega je 12 okarakterisano rentgeno-strukturnom analizom. U zavisnosti od pH sva tri liganda se mogu koordinovati kao neutralni, mono-, odnosno, dianjoni sa uobičajenim ONO, ONS i ONN setom donorskih atoma, respektivno, pri čemu neutralna i monoanjonska forma liganada postoji u obliku zwitter-jona. U slučaju PLTSC a na primerima dva dimerna kompleksa bakra nađen je i ređi tetradentatni ONSO način koordinacije, tj. učešće i atoma kiseonika hidroksimetil grupe kao mostovnog atoma. Sva tri liganda sa Cu(II), nezavisno od stehiometrije Cu:ligand, daju mono(ligand) komplekse kvadratno-planarne, kvadratno-piramidalne ili oktaedarske strukture, a sa kobaltom mono- i bis(ligand) oktaedarske komplekse. Dobijenim mono(ligand) kompleksima Zn(II) sa sva tri liganda je pripisana najmanje tetra-, odnosno pentakoordinacija, dok je mešovitim PLSC(PLTSC)/NCS i bis(ligand) kompleksima Cr(III), i mono(ligand) kompleksu Fe(III) sa PLTSC pripisuje oktaedarska struktura. Ni(II) sa PLTSC i PLITSC daje mono- i dinuklearne komplekse, dok Cd(II) sa istim ligandima gradi mono(ligand) komplekse. Sva jedinjenja su okarakterisana parcijalnom mikroanalizom, IR-spektrima i konduktometrijskim merenjima, a odabrani kompleksi rentgeno-strukturnom, termogravimetrijskom i toksikološkom analizom.The work describes the syntheses, physico-chemical, structural and antibacterial characteristics of Cu(II), Co(II), Co(III), Zn(II), Ni(II), Fe(III), Cr(III) and Cd(II) complexes with semi-, thiosemi- and S-methylisothiosemicarbazones. The result of the syntheses was 2 new ligand forms and 37 complexes, of which 12 were characterized by X-ray structural analysis. Depending of the pH, all three ligands can be coordinated either as neutral, monoanion, or dianion, using ONO, ONS and ONN set of donor atoms, respectively, whereby the neutral and monoanionic forms of the ligands exist in the form of zwitter-ions. All three ligands form with Cu(II), irrespective of the stoichiometry Cu:ligand, give mono- and dinuclear complexes of square-planar, square-pyramidal and/or octahedral configuration and with cobalt mono- and bis(ligand) octahedral complexes. The obtained mono(ligand) complexes of Zn (II) with all three of ligands is attributed to the at least tetra-, or pentacoordination, while the mono- and bis(ligand) complexes of Cr(III) with PLSC and PLTSC, and mono (ligand)complex of Fe(III) with PLTSC attributable to octahedral structure. Ni(II) with PLTSC and PLITSC forms mono- and binuclear complexes, and Cd(II) with the same ligands forms mono(ligand) complexes. All the compounds were characterized by partial microanalysis, IR spectra and conductometric measurements, while some selected complexes were examined by X-ray structural, thermogravimetric and toxicological analysis.
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Zouharová, Kamila. "Příprava a základní chemická a fyzikální charakterizace biouhlu z pšeničných otrub." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-432668.
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At present, the extraction of biochar and its use is a much-discussed topic in the chemical and research fields. The use of biochar is very often declined in the areas of agriculture, waste management, environmental improvement and the fight against global warming. In addition to these sectors, the topic of biochar is also addressed in the production of bio-diesel and bio-oil. Due to the current use of secondary products during biotechnological processes, the presented theoretical and practical study focused on the issue of obtaining biochar from bran by pyrolysis at different temperatures. Part of the practical part was the extraction of biochar from bran and its subsequent analysis, which could be used to characterize biochar obtained from bran by pyrolysis physically and chemically. The characterization of bran biochar was solved by various analytical methods. These techniques yielded, for example, pH, conductivity, particle distribution, elemental composition of biochar, porosity and content of polycyclic aromatic hydrocarbons. Thanks to this study, the properties of biochar and its possible applications in everyday life were characterized in detail. Given the very promising use of biochar obtained from bran, it can be said that this will be a very desirable topic for the future.