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1
Karlkvist, Tommy. "Design and Development of Mineral Structure Specific Collectors in Flotation." Licentiate thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18421.
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The success of mineral flotation processes depends on the hydrophobization of the surface for the desired mineral particles whilst keeping, or making, all other minerals hydrophilic. This is achieved by adding several reagents to the flotation pulp to adsorb selectively at the mineral/water interface. The reagents (surface active agents) which selectively adsorbs on minerals to be floated are called collectors. It is realized that many of these commonly used reagents are highly toxic and often potential threats to the environment. Use of many of theseconventional chemicals will therefore be restricted soon and must eventually be stopped. An immediate effort is necessary to develop alternative eco-friendly reagents in order to continue to extract valuable minerals from ores. In addition, with the steady depletion of high grade, relatively easy to process ores, the mineral industry is confronted with a challenging task of finding more efficient techniques so as to exploit low grade, complex and disseminated typeof ore deposits and old tailing dumps. The development of new selective and environmentally acceptable substances containing almost tailor-made reagents is thus inevitable for sustainability. Several known chelating agents have been appropriately modified to make those behave as selective flotation collectors with some degree of success. The problem is that almost all of the chelating groups form complexes with almost all of the transition and many non-transition metals. As a consequence, absolute selectivity does not exist. Besides beingunsatisfactory from a scientific viewpoint, it assumes that the metal ion specificity observed for a functional group in bulk aqueous system would remain valid during surface chelation at the interface, while in actual practice, the specificity based on metal ion is neither valid nor useful where the cations participating in the complexation reactions are the same, for example separation among the calcium minerals.It is clear that a selective reagent should be based on the reagent interactions not merely with the metal ion on the surface, but with the whole surface. It is more appropriate to design reagents having functional groups so spaced that those are compatible with the relative positions of the metal ion sites available on the surface, that is, to design not just metalspecificbut structure-specific reagents. The understandings of molecular interactions involved in the recognition of surfaces by organic molecules in biomineralization process suggest the possibility of reagents specific to the crystal structure. These understandings have been successfully applied to the rational design and synthesis of molecules either for the control of crystal morphology or to inhibitcrystal growth processes through the recognition of specific crystal surfaces. The idea of molecules consisting of two groups having appropriate spacing between them to achieve structural compatibility during interaction with surface exhibit structure-specificity is of direct relevance to the reagents selectivity in flotation processes. The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying spacing between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant withthe same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite, calcite and fluorite mineral surfaces was studied using Hallimond tube flotation, ζ-potential and FTIR measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much moreselective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ-potential and infrared spectroscopy data. Our investigation revealed that it is possible to design and develop mineral specific reagents in flotation.<br>Godkänd; 2014; 20140430 (andbra); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Tommy Karlkvist Ämne: Mineralteknik/Mineral Processing Uppsats: Design and Development of Mineral Structure Specific Collectors in Flotation Examinator: Professor Kota Hanumantha Rao, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: PhD, Principal Scientist Beena Rai, Tata Research Development and Design Centre, Pune, India Tid: Fredag den 13 juni 2014 kl 10.00 Plats: F531, Luleå tekniska universitet
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Niedzwiecki, Lukasz. "Energy requirements for comminution of fibrous materials - qualitative chipping model." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-12298.
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This paper aims to derive qualitative model for energy requirements for wood chipping process. There is relationship shown between energy requirements and properties of biomass, which is quite variable material. Relationship between comminution machinery and energy necessary for the process is highlighted. Derivation of the model is focused on chipping but in general it’s possible, to make it available both for different types of biomass (f. ex. agricultural residues) or for different type of comminution machinery (f. ex. hammermills) just by using different material properties adjusted to machinery mechanics. Properties used in derivation are mend to be easy to measure. Model is mend to be used as a base for quantitative model that, thanks to measurements performed on real comminution machinery and using wood with known properties, could give answers for two important questions: Would hypothetical changes in desired size of output material increase total system efficiency, taking into consideration lowest efficiency of combustion process (i. ex. higher amounts of unburned fuel)? How to optimise comminution as an operation in biofuel supply chain, with respect to energy used for the process?
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Blanchard, Jeffrey Allen 1974. "Specific gas sensing using zirconia amperometric oxygen sensors." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/278662.
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An analytical model for the specific gas detection of oxygen, carbon dioxide, and water vapor using zirconia amperometric oxygen sensors has been developed. Sensors of this type have been designed, fabricated, and tested using planar ceramic technology. Furthermore, an experimental setup has been designed and constructed for sensor characterization. This testbed can accurately control gas partial pressures as well as the total system pressure over a wide range of flow rates. Extensive effort has been put into design and construction of this testbed to ensure accurate scientific measurements. Special attention has been paid to ensuring that the apparatus is leak-tight from air to ensure accurate measurements at low oxygen partial pressures. Results of the experimentation for oxygen detection as well as the detection of carbon dioxide and water vapor are presented. The effects of electronic conduction in the zirconia electrolyte at low oxygen partial pressures are examined. Possible applications of the sensor, as well as suggestions for further research are discussed.
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Mohammed, K. A. "Low temperature specific heat measurements of crystalline and amorphous magnetic materials." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356096.
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Goh, Tee Yong. "Olefin/paraffin separation using task-specific materials based on ionic liquids." Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.726635.
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The separation of light olefins/paraffins, which is one important process in industry, is usually carried out using cryogenic distillation that heavily depends on the difference of the various components’ boiling points and volatilities. Nevertheless, the close boiling point between an olefin and its corresponding paraffin is an absolute challenge for this process, and hence low temperature (e.g. -13 to -30 °C) and high pressure (e.g. 20-25 bar) are required. It is therefore energy intensive, resulting high cost for the separation processes (e.g. more than $500 million for ethylene unit). Thus, the aims of this project are not only to discover alternative methods to separate light olefin and paraffin mixtures, but also to substitute the conventional energy and cost intensive separation process.The selected alternatives must have the ability to achieve high selectivity in the olefin/paraffin separation, and, more importantly, consume less energy and have lower costs compared to the traditional methods used in industry (e.g. distillations). As a result, in this project ionic liquids are studied in order to improve the separation process of olefin/paraffin thanks to their ability to selectively solubilise olefins. Transition metals such as silver, which is able to form electron donor/acceptor complexes with olefins have also been chosen to be investigated, with the intention of improving the selectivity of the separation. It is important that an alternative technology will focus on solving present existing dilemma of separation processes; which are the issues of operating temperature and pressure, solvent losses as well as the stability of the chosen transition metal.
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Klein, Katherine. "Electromagnetic properties of high specific surface minerals." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20699.
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Nyeanchi, Emmanuel Bongkiyung. "Resistivity and specific heat capacity of high Tc superconductors and magnetic materials." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239591.
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Cachinho, Sandra C. P. "The potential of materials to initiate events in innate and specific immunity pathways." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526953.
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Leigh, Nigel Royston. "Specific heat measurements on chevrel phase materials exhibiting coexistence of superconductivity and magnetism." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3849/.
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A probe for measuring the specific heat of superconductors at low temperatures and in high magnetic fields has been built and commissioned. The probe has been tested using the relaxation method on samples of copper and the accuracy of the data is 1.3 % between 5 K and 30 K, data taken using the long range pulse method has a resolution of 10 mK. Specific heat measurements have been performed on members of the series (Pb(_1)-(_x))Cu(_1.8x)Mo(_6)S(_8), (Sn(_1-x))Eu(_x)Mo(_6)S(_8) and (Pb(_1-x)M(_x))Mo(_6)S(_8) where M = Gd and Eu, from 3 K up to 30 K and in magnetic fields up to 15 T. Additional results from resistivity, susceptibility, magnetisation. X-ray diffraction, transmission electron microscopy and electron dispersive-ray measurements are also presented. These data have been compared to results from other authors and are analysed in terms of the BCS and GLAG theories of superconductivity and the magnetic properties of these materials. The mean field model has been used to calculate numerically the magnetic contribution to the specific heat (cm) of both ferromagnetic and antiferromagnetic systems as a function of temperature and applied field both above and below the ordering temperature. In addition an approximate analytic form for the magnetisation has been used to calculate Cm above the ordering temperature. Expressions have been derived for the saturation value of the peak in C(_m): C(^sat)(_m) = 1.1245n(_cell)RJI(J+1) and the temperature dependence of the peak with applied field ȡ(μ(_o)H(_ext))/ȡT(_peak)=6.540/g(_J)(J+1). They allow the simple calculation of the values of J and g(_J)(J + 1) from specific heat data. The magnetic contribution to the specific heat of the samples (Sn(_0.65)Eu(0.35)Mo(_6)S(_8)) and (Sn(0.50)Eu(_0.50)Mo(_6)S(_8)) have been modelled using these calculations and excellent agreement is found by considering the magnetic ions as free ions. The sample is accurately modelled by including an additional minority phase (Gd(_2)S(_3)). The approximate expressions have also been used to analyse data on high temperature superconductors producing values of J and g(_J)}{J + 1) consistent with a doublet ground state. The properties of Chevrel phase materials have been determined as a function of doping level. The critical temperature is degraded by doping but an increase in the critical current density is observed in the series (Pb(_1-x)Cu(_1-8x)Mo(_6)S(_8) for very low levels of doping. Increases of up to 28 % in the upper critical field, that are probably due to the compensation effect and an increase in the normal state resistivity, are also observed in the series (Sn(_1-x)Eu(_x)Mo(_6)S(_8)) at high levels of doping and in the series (Pb(_1-x)Gd(_x)Mo(_6)s(_8) for low levels of doping.
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Velay, Xavier. "Analysis of the conform process : a specific form of aluminium extrusion." Thesis, Bournemouth University, 2004. http://eprints.bournemouth.ac.uk/432/.
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Since the Conform process was patented 30 years ago, there have only been approximately 200 machines sold worldwide. Given that Conform competes economically with conventional extrusion and is also reported to be a more energy efficient process, it is surprising that the use of Conform is not more widespread in today's increasingly environmentally conscious and high-production focussed world. One explanation for this is likely to be due to the fact that there is still limited knowledge of the thermo-mechanical behaviour of the workpiece during extrusion. Furthermore, for the aluminium industry, there are still issues remaining regarding the production of flash and the quality of the extrudate in terms of mechanical properties. This study provides the reader with the findings of the research and experimental work undertaken by the author, his co-workers and fellow specialists, in the field of aluminium extrusion including Conform. The experimental work includes both laboratory experiments performed with a direct extrusion press and an experimental machine set up to replicate the Conform process. The experimental work is also simulated using finite element modelling techniques. The results from these analyses are then validated by comparing industrial and experimental data. The finite element analyses are enhanced by using parallel processing technology and user sub-routines. The author proposes new models to allow for the study of the different sub-processes in Conform. These include the coining of the feedstock, formation of the upset zone, extrusion of the flash, the filling-up of the expansion chamber / feeder plate and the extrusion of the extrudate. The author also investigates methods which predict microstructure and surface cracks in the extrudate. The author suggests innovative techniques to improve the efficiency of finite element analysis in metal forming. Finally the author recommends procedures for the study of structural integrity and the optimisation of the tooling used in Conform.
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Lebold, Timo, Julia Blechinger, Lea Mühlstein, et al. "Mesopore functionalization as highly specific tool for the control of single molecule dynamics in silica materials: Mesopore functionalization as highly specific tool for the control ofsingle molecule dynamics in silica materials." Diffusion fundamentals 6 (2007) 65, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14243.
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Olsson, Birgitta. "Teaching Materials within Program Specific Courses Promoting Integration with English at Upper Secondary School." Thesis, Högskolan i Gävle, Avdelningen för humaniora, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-12235.
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Beranek, Maggi Marie. "The influence of surface integrin binding patterns on specific biomaterial-cell interations [i.e., interactions] a dissertation /." San Antonio : UTHSC, 2008. http://proquest.umi.com.libproxy.uthscsa.edu/pqdweb?did=1588776891&sid=1&Fmt=2&clientId=70986&RQT=309&VName=PQD.
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Chan, Sen Ki. "Development and characterization of functionalized magnetic nanoparticle-based method for species-specific genomic DNA extraction /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CBME%202008%20CHAN.
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Avsejs, Luke Andrei. "The organic geochemistry and compound specific radiocarbon dating of peat and other sedimentary materials." Thesis, University of Bristol, 2001. http://hdl.handle.net/1983/ca4a9987-e6ea-415f-8320-5f00eba984a6.
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Sanguinet, William Charles. "Various extensions in the theory of dynamic materials with a specific focus on the checkerboard geometry." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-dissertations/243.
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This work is a numerical and analytical study of wave motion through dynamic materials (DM). This work focuses on showing several results that greatly extend the applicability of the checkerboard focusing effect. First, it is shown that it is possible to simultaneously focus dilatation and shear waves propagating through a linear elastic checkerboard structure. Next, it is shown that the focusing effect found for the original €œperfect€� checkerboard extends to the case of the checkerboard with smooth transitions between materials, this is termed a functionally graded (FG) checkerboard. With the additional assumption of a linear transition region, it is shown that there is a region of existence for limit cycles that takes the shape of a parallelogram in (m,n)-space. Similar to the perfect case, this is termed a €œplateau€� region. This shows that the robustness of the characteristic focusing effect is preserved even when the interfaces between materials are relaxed. Lastly, by using finite volume methods with limiting and adaptive mesh refinement, it is shown that energy accumulation is present for the functionally graded checkerboard as well as for the checkerboard with non-matching wave impedances. The main contribution of this work was to show that the characteristic focusing effect is highly robust and exists even under much more general assumptions than originally made. Furthermore, it provides a tool to assist future material engineers in constructing such structures. To this effect, exact bounds are given regarding how much the original perfect checkerboard structure can be spoiled before losing the expected characteristic focusing behavior.
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Kenney, Floyd E. "Biosensor Production By Conjugation Of HSA-Specific Peptide To Functionalized Nanotube Fiber." Youngstown State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525360589515967.
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Tarawhiti, Nancy Waireana. "The Development of a Certified Nursing Assistant English for Specific Purposes Curriculum: Teaching Materials and Methods." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd967.pdf.
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Lebold, Timo, Julia Blechinger, Lea Mühlstein, et al. "Mesopore functionalization as highly specific tool for the control of single molecule dynamics in silica materials." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194043.
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Panagiotopoulou, Maria. "Organic-inorganic composite materials for specific recognition and optical detection of environmental, food and biomedical analytes." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2315/document.
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Cette thèse décrit l'état de l'art des sondes et nanoparticules fluorescents traditionnels utilisés en imagerie de fluorescence ainsi que le développement de nouveaux nanomatériaux à base de polymère à empreinte moléculaire, aussi dénommé ‘anticorps plastique’, pour le ciblage et la bioimagerie. En biologie et en médecine, il y a un besoin constant de diagnostiquer diverses maladies pour leur éventuel traitement et prévention. Une distribution anormale et un taux élévé de glycosylation (e.g. acides hyaluronique et sialique) à la surface ou dans les cellules sont indicateurs d’une infection ou d’un cancer. Généralement, l’imagerie par fluorescence permet de visualiser, localiser et quantifier les biomarqueurs de pathologie mais à l’heure actuelle, il n’existe pas d’outil analytique fiable pour cibler spécifiquement les molécules de glycosylation car les anticorps et les lectines vendus dans le commerce ont une faible affinité et sélectivité vis-à-vis de ces cibles. Dans ce contexte, les polymères à empreintes moléculaires (MIPs) pourraient apporter une solution. Les MIPs sont des récepteurs synthétiques possédant des affinités et sélectivités comparables à ceux des anticorps, mais exhibant une stabilité physique, thermique et chimique bien plus accrue. De plus, leur fabrication est peu coûteuse et ne nécessite pas de tuer des animaux comme pour l’obtention des anticorps biologiques. Dans cette thèse, nous avons optimisé et synthétisé des MIPs biocompatibles pour leur utilisation en bioimagerie afin de détecter et quantifier l’acide hyaluronique et l’acide sialique sur les cellules et les tissus de peau humaine. L’acide glucuronique, une composante de l’acide hyaluronique et l’acide N-acétylneuraminique, l’acide sialique le plus commun, ont été utilisés comme molécules ‘patron’, générant des MIPs très sélectifs envers leur cible en milieu aqueux. Deux types de nanoparticules de MIPs fluorescents ont été synthétisés: (1) en incorporant un colorant rhodamine polymérisable dans la solution de pré-polymérisation et (2) en encapsulant des boîtes quantiques InP/ZnS générant ainsi des MIPs de type cœur-coquille. Pour cela, nous avons adopté une stratégie innovante qui consiste à synthétiser les coquilles de MIPs directement autour des boîtes quantiques en utilisant l’énergie de l’onde fluorescente émise par l’excitation des points quantiques, pour initier la polymérisation. Un protocole d'immunocoloration standard a ensuite été optimisé afin d’imager des kératinocytes humains fixés et vivants ainsi que des tissus de peau, par microscopie à épifluorescence et confocale. Les résultats étaient similaires à ceux obtenus par la méthode de référence utilisant une protéine biotinylée reconnaissant l'acide hyaluronique. L'imagerie multiplex en combinant deux MIPs couplés à deux couleurs de boîtes quantiques et l’imagerie des cellules cancéreuses ont également été démontrées. Bien que les MIPs n’étaient pas cytotoxiques aux concentrations utilisées pour la bioimagerie, la toxicité des différentes composantes du MIP pourrait être un frein à leur utilisation dans le domaine biomédical. Afin de rendre ces MIPs plus ‘inoffensifs’, nous avons supprimé l’amorceur de polymérisation, une molécule considérée comme toxique. Les MIPs ont été synthétisés en employant des monomères qui s’auto-initient sous l’effet de l’UV ou de la chaleur. La spécificité et la sélectivité des MIPs obtenus étaient similaires à ceux préparés avec des amorceurs. En conclusion, cette thèse décrit la première utilisation des MIPs comme anticorps synthétique pour la bioimagerie de fluorescence. Ce travail ouvre la voie à de nouvelles applications en détection, diagnostique et thérapie par des MIPs<br>This thesis describes the state of the art in nanomaterials-based targeted bioimaging and introduces molecularly imprinted polymers, also termed ‘plastic antibodies’ as novel biorecognition agents for labeling and imaging of cells and tissues. In fundamental biology and medical diagnostics, there is a constant need to localize and quantify specific molecular targets. Abnormal glycosylation levels or distributions of hyaluronan or sialic acids on cells are indicators of infection or malignancy. In general, bioimaging with fluorescent probes enables the localization and qualitative or quantitative determination of these pathological biomarkers. However, no reliable tools for the recognition of glycosylation sites on proteins exist, because the commercially available antibodies or lectins have poor affinity and selectivity for these targets. In this context, tailor-made molecularly imprinted polymers (MIPs) are promising synthetic receptor materials since they present a series of advantages over their natural counterparts such as the ease and low cost of preparation and their physical and chemical stability. Thus, MIPs could provide a robust and specific imaging tool for revealing the location/distribution, time of appearance and structure of glycosylation sites on/in cells, which would lead to a better insight of the tremendously diverse biological processes in which these molecules are involved. Herein, we describe the synthesis of water-compatible MIPs for the molecular imaging of hyaluronan and sialylation sites on cells and tissues. Since molecular imprinting of entire biomacromolecules like oligosaccharides is challenging, we opted for what is commonly called the ‘epitope approach’, which was inspired by nature. The monosaccharides, glucuronic acid and N-acetylneuraminic acid were imprinted, and the resulting MIPs were able to bind these molecules when present and accessible on the terminal unit of hyaluronan and sialylation sites. Fluorescent MIPs were synthesized as rhodamine-labeled nanoparticles and as MIP-coated InP/ZnS core-shell quantum dot (QD) particles. For the coating of the QDs, a novel versatile solubilization and functionalization strategy was proposed, which consists of creating polymer shells directly on QDs by photopolymerization using the particles as individual internal light sources. A standard immunostaining protocol was then successfully adapted for the application of the fluorescently labeled MIPs to image fixed and living human keratinocytes and skin tissues, by epifluorescence and confocal fluorescence microscopy. The results were comparable to those obtained with a reference method where staining was done with a biotinylated hyaluronic acid binding protein. Multiplexed and cancer cell imaging were also performed, demonstrating the potential of molecularly imprinted polymers as a versatile biolabeling and bioimaging tool. Although the MIPs were not cytotoxic at the concentrations used for bioimaging, in order to render them generally applicable in biomedicine, where toxicity of the polymerization precursors is a matter of concern, we suppressed the initiator, a toxic chemical. Initiator-free MIPs were thus synthesized by using monomers that can self-initiate under UV irradiation or heat. The specificity and selectivity of the obtained MIPs were as good as the ones prepared with initiators. In conclusion, we have demonstrated for the first time the great potential of MIPs as synthetic antibody mimics for bioimaging. The possibility to associate other functionalities such as QDs and additionally attach drugs to the same material appears rather straightforward due to the synthetic polymeric nature of MIPs, which paves the way to new potential applications in theranostics
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Kock, Jeffrey Wayne. "Physical and Mechanical Properties of Chicken Feather Materials." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10555.
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Materials derived from chicken feathers could be used advantageously in composite building material applications. Such applications could potentially consume the five billion pounds of feathers produced annually as a by-product of the U.S. poultry industry. To aid the development of successful applications for chicken feather materials (CFM), the physical and mechanical properties of processed CFM have been characterized in this research. Results describing the moisture content, aspect ratio, apparent specific gravity, chemical durability, Youngs modulus, and tensile strength for processed CFM and specifically their fiber and quill components are presented herein. Processed chicken feather fiber and quill samples were found to have similar moisture contents in the range of 16 - 20%. The aspect ratio (i.e., length/diameter) of samples were found to be in the range of 30 - 50, and the fiber material was found to have a larger aspect ratio than the quill material. A comparison with values in the literature suggests that different processing regimes produce CFM with higher aspect ratios. Samples were found to have apparent specific gravities in the range of 0.7 - 1.2, with the fiber material having a higher apparent specific gravity than the quill material. A comparison with values in the literature suggests that apparent specific gravity results vary with fiber length and approach the value for keratin as fiber length decreases and internal voids become increasingly accessible. Chemical durability results showed that CFM rapidly degrade in highly alkaline (pH=12.4) environments and are, thus, likely incompatible with cement-based materials without special treatment. The Youngs modulus of processed chicken feather materials was found to be in the range of 3 - greater than 50 GPa and, thus, comparable to the Youngs moduli of other natural fibers. The tensile strength of oven-dried samples was found to be in the range of 10 - greater than 70 MPa. In agreement with results in the literature, the fiber material was found to have a greater tensile strength than the quill material. Finally, a simplified approach for comparing the effective Youngs moduli and effective tensile strengths of various processed CFM samples was introduced.
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Lang, Brian E. "Specific Heat and Thermodynamic Properties of Metallic Systems: Instrumentation and Analysis." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/785.
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A small-scale adiabatic calorimeter has been constructed as part of a larger project to study nano-particles and to facilitate specific heat measurements on samples where it is difficult to obtain enough material to run on the current large-scale adiabatic apparatus. This calorimeter is designed to measure sample sizes of less than 0.8 cc over a temperature range from 13 K to 350 K. Specific heat results on copper, sapphire, and benzoic acid show the accuracy of the measurements to be better than ±0.4% for temperatures higher than 50 K. The reproducibility of these measurements is generally better than ±0.25%. Experimental specific heat data was collected on this new apparatus for synthetic akaganeite, β-FeOOH, for samples with varying degrees of hydration. Our results yield values for Δ_0^298.15S°m of 79.94 ±0.20 J•K^-1•mol^-1 and 85.33 ±0.021 J•K^-1•mol^-1 for samples of β-FeOOH0.551H2O and β-FeOOH0.652H2O, respectively. From this data, we were able to determine the standard molar entropy for bare β-FeOOH, as Δ_0^298.15S°m = 53.8 ±3.3 J•K^-1•mol^-1, based on subtractions of the estimated contribution of water from the hydrated species. Additionally, the specific heats of α-uranium, titanium diboride, and lithium flouride have been measured on a low-temperature, semi-adiabatic calorimeter down to 0.5 K. For the α-uranium, the specific heat of a polycrystalline sample was compared to that of a single crystal, and it was found that there was a significant difference in the specific heats, which has been attributed to microstrain in the polycrystal. The third law entropy for the polycrystal at 298.15 K, Δ_0^298.15S°m, calculated from these heat capacities is 50.21 ±0.1 J•K^-1•mol^-1, which is good in agreement with previously published values of polycrystal samples. For the single crystal Δ_0^298.15S°m, calculated using the thermodynamic microstrain model, is 49.02 ±0.2 J•K^-1•mol^-1. The low-temperature specific heats of titanium diboride and lithium fluoride have been measured from 0.5 K to 30 K as part of a larger project in the construction of a neutron spectrometer. For this application, the measured specific heats were used to extrapolate the specific heats down to 0.1 K with lattice, electronic, and Schottky equations for the respective samples. The resultant specific heat values at 0.1 K for TiB2 and 6LiF are 4.08E-4 ±0.27E-4 J•K^-1•mol^-1 and 9.19E-9 ±0.15E-9 J•K^-1•mol^-1, respectively.
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Schaser, Matt Saxon. "Material Specific Load Combination Factors for Option 2 FAD Curves." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1386078154.
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Koppanooru, Sampat Kumar Reddy. "Estimating Thermal Conductivity and Volumetric Specific Heat of a Functionally Graded Material using Photothermal Radiometry." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062896/.
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Functionally graded materials (FGMs) are inhomogeneous materials in which the material properties vary with respect to space. Research has been done by scientific community in developing techniques like photothermal radiometry (PTR) to measure the thermal conductivity and volumetric heat capacity of FGMs. One of the problems involved in the technique is to solve the inverse problem, i.e., estimating the thermal properties after the frequency scan has been obtained. The present work involves finding the unknown thermal conductivity and volumetric heat capacity of the FGMs by using finite volume method. By taking the flux entering the sample as periodic and solving the discretized 1-D thermal wave field equation at a frequency domain, one can obtain the complex temperatures at the surface of the sample for each frequency. These complex temperatures when solved for a range of frequencies gives the phase vs frequency scan which can then be compared to original frequency scan obtained from the PTR experiment by using a residual function. Brute force and gradient descent optimization methods have been implemented to estimate the unknown thermal conductivity and volumetric specific heat of the FGMs through minimization of the residual function. In general, the spatial composition profile of the FGMs can be approximated by using a smooth curve. Three functional forms namely Arctangent curve, Hermite curve, and Bezier curve are used in approximating the thermal conductivity and volumetric heat capacity distributions in the FGMs. The use of Hermite and Bezier curves gives the flexibility to control the slope of the curve i.e. the thermal property distribution along the thickness of the sample. Two-layered samples with constant thermal properties and three layered samples in which one of the layer has varying thermal properties with respect to thickness are considered. The program is written in Fortran and several test runs are performed. Results obtained are close to the original thermal property values with some deviation based on the stopping criteria used in the gradient descent algorithm. Calculating the gradients at each iteration takes considerable amount of time and if these gradient values are already available, the problem can be solved at a faster rate. One of the methods is extending automatic differentiation to complex numbers and calculating the gradient values ahead; this is left for future work.
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Bhattarai, Bishal. "Ab initio Structure Inversion for Amorphous Materials." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1537349044469989.
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Willey, Tim Vincent. "Design-construction incorporating sustainable materials from environmentally valuable ecosystems : a model for practice developed through site-specific case studies." Thesis, University of Derby, 2004. http://hdl.handle.net/10545/251612.
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Reyes, Catherine Diane. "Collagen- and Fibronectin-Mimetic Integrin-Specific Surfaces That Promote Osseointegration." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11599.
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Cell adhesion to the extracellular matrix through cell-surface integrin receptors is essential to development, wound healing, and tissue remodeling and therefore represents a central theme in the design of bioactive surfaces that successfully interface with the body. This is especially significant in the areas of integrative implant coatings since adhesion triggers signals that regulate cell cycle progression and differentiation in multiple cellular systems. The interactions of osteoblasts with their surrounding extracellular matrix are essential for skeletal development and homeostasis and the maintenance of the mature osteoblastic phenotype. Our objective was to engineer integrin-specific bioactive surfaces that support osteoblastic differentiation and promote osseointegration by mimicking these interactions. We target two specific integrins essential to osteoblast differentiation the type I collagen receptor alpha2beta1 and the fibronectin receptor alpha5beta1. The central hypothesis of this project was that the controlled presentation of type I collagen and fibronectin binding domains onto well-defined substrates would result in integrin-specific bioadhesive surfaces that support osteoblastic differentiation, matrix mineralization, and osseointegration. We have demonstrated that these biomimetic peptides enhance bone formation and mechanical osseointegration on titanium implants in a rat tibia cortical bone model. We have also shown that the presentation of multiple integrin-binding ligands synergize to enhance intracellular signaling and proliferation. Finally, we demonstrate the advantage of the short biomimetic peptides over the native ECM proteins. This research is significant because it addresses current orthopaedic implant limitations by specifically targeting cellular responses that are critical to osteoblastic differentiation and bone formation. This biomolecular approach provides a versatile and robust strategy for developing bioactive surfaces that enhance bone repair and osseointegration of orthopaedic implants.
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Brahmbhatt, H. A., Alexander P. H. Surtees, C. Tierney, et al. "Effect of polymerisation by microwave on the physical properties of molecularly imprinted polymers (MIPs) specific for caffeine." Royal Society of Chemistry, 2020. http://hdl.handle.net/10454/18143.
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Yes<br>Molecularly Imprinted Polymers (MIPs) are a class of polymeric materials that exhibit highly specific recognition properties towards a chosen target. These “smart materials” offer robustness to work in extreme environmental conditions and cost effectiveness; and have shown themselves capable of the affinities/specificities observed of their biomolecular counterparts. Despite this, in many MIP systems heterogeneity generated in the polymerisation process is known to affect the performance. Microwave reactors have been extensively studied in organic chemistry because they can afford fast and well-controlled reactions, and have been used for polymerisation reactions; however, their use for creating MIPs is limited. Here we report a case study of a model MIP system imprinted for caffeine, using microwave initiation. Experimental parameters such as polymerisation time, temperature and applied microwave power have been investigated and compared with polymers prepared by oven and UV irradiation. MIPs have been characterised by BET, SEM, DSC, TGA, NMR, and HPLC for their physical properties and analyte recognition performance. The results suggest that the performance of these polymers correlates to their physical characteristics. These characteristics were significantly influenced by changes in the experimental polymerisation parameters, and the complexity of the component mixture. A series of trends were observed as each parameter was altered, suggesting that the performance of a generated polymer could be possible to predict. As expected, component selection is shown to be a major factor in the success of an imprint using this method, but this also has a significant effect on the quality of resultant polymers suggesting that only certain types of MIPs can be made using microwave irradiation. This work also indicates that the controlled polymerisation conditions offered by microwave reactors could open a promising future in the development of MIPs with more predictable analyte recognition performance, assuming material selection lends itself to this type of initiation.<br>DMU School of Pharmacy undergraduate project scheme for financial support.<br>The full-text of this article will be released for public view at the end of the publisher embargo on 13 Aug 2021.
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Basnayaka, Punya A. "Development of Nanostructured Graphene/Conducting Polymer Composite Materials for Supercapacitor Applications." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4864.
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The developments in mobile/portable electronics and alternative energy vehicles prompted engineers and researchers to develop electrochemical energy storage devices called supercapacitors, as the third generation type capacitors. Most of the research and development on supercapacitors focus on electrode materials, electrolytes and hybridization. Some attempts have been directed towards increasing the energy density by employing electroactive materials, such as metal oxides and conducting polymers (CPs). However, the high cost and toxicity of applicable metal oxides and poor long term stability of CPs paved the way to alternative electrode materials. The electroactive materials with carbon particles in composites have been used substantially to improve the stability of supercapacitors. Furthermore, the use of carbon particles and CPs could significantly reduce the cost of supercapacitor electrodes compared to metal oxides. Recent developments in carbon allotropes, such as carbon nanotubes (CNTs) and especially graphene (G), have found applications in supercapacitors because of their enhanced double layer capacitance due to the large surface area, electrochemical stability, and excellent mechanical and thermal properties.
The main objective of the research presented in this dissertation is to increase the energy density of supercapacitors by the development of nanocomposite materials composed of graphene and different CPs, such as: (a) polyaniline derivatives (polyaniline (PANI), methoxy (-OCH3) aniline (POA) and methyl (-CH3) aniline (POT), (b) poly(3-4 ethylenedioxythiophene) (PEDOT) and (c) polypyrrole (PPy). The research was carried out in two phases, namely, (i) the development and performance evaluation of G-CP (graphene in conducting polymers) electrodes for supercapacitors, and (ii) the fabrication and testing of the coin cell supercapacitors with G-CP electrodes.
In the first phase, the synthesis of different morphological structures of CPs as well as their composites with graphene was carried out, and the synthesized nanostructures were characterized by different physical, chemical and thermal characterization techniques, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, BET surface area pore size distribution analysis and Thermogravimetric Analysis (TGA). The electrochemical properties of G-CP nanocomposite-based supercapacitors were investigated using Cyclic Voltammetry (CV), galvanostatic charge-discharge and Electrochemical Impedance Spectroscopy (EIS) techniques in different electrolytes, such as acidic (2M H2SO4 and HCl), organic ( 0.2 M LiClO4) and ionic liquid (1M BMIM-PF6) electrolytes.
A comparative study was carried out to investigate the capacitive properties of G-PANI derivatives for supercapacitor applications. The methyl substituted polyaniline with graphene as a nanocomposite (G-POT) exhibited a better capacitance (425 F/g) than the G-PANI or the G-POA nanocomposite due to the electron donating group of G-POT. The relaxation time constants of 0.6, 2.5, and 5s for the G-POT, G-PANI and G-POA nanocomposite-based supercapacitors were calculated from the complex model by using the experimental EIS data.
The specific capacitances of two-electrode system supercapacitor cells were estimated as 425, 400, 380, 305 and 267 F/g for G-POT, G-PANI, G-POA, G-PEDOT and G-PPy, respectively. The improvements in specific capacitance were observed due to the increased surface area with mesoporous nanocomposite structures (5~10 nm pore size distribution) and the pseudocapacitance effect due to the redox properties of the CPs. Further, the operating voltage of G-CP supercapacitors was increased to 3.5 V by employing an ionic liquid electrolyte, compared to 1.5 V operating voltage when aqueous electrolytes were used. On top of the gain in the operating voltage, the graphene nano-filler of the nanocomposite prevented the degradation of the CPs in the long term charging and discharging processes.
In the second phase, after studying the material's chemistry and capacitive properties in three-electrode and two-electrode configuration-based basic electrochemical test cells, coin cell type supercapacitors were fabricated using G-CP nanocomposite electrodes to validate the tested G-CPs as devices. The fabrication process was optimized for the applied force and the number of spacers in crimping the two electrodes together. The pseudocapacitance and double layer capacitance values were extracted by fitting experimental EIS data to a proposed equivalent circuit, and the pseudocapacitive effect was found to be higher with G-PANI derivative nanocomposites than with the other studied G-CP nanocomposites due to the multiple redox states of G-PANI derivatives. The increased specific capacitance, voltage and small relaxation time constants of the G-CPs paved the way for the fabrication of safe, stable and high energy density supercapacitors.
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Rothenbach, Nico [Verfasser], and Heiko [Akademischer Betreuer] Wende. "Femtosecond time-resolved soft X-ray spectroscopy for an element-specific analysis of complex materials / Nico Rothenbach ; Betreuer: Heiko Wende." Duisburg, 2020. http://d-nb.info/1221960261/34.
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Kashoob, Muna. "Evaluating ELT materials, with specific reference to Colleges of Applied Sciences General Foundation Programme in Oman : towards a viable checklist." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/20915/.
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The main question and purpose of this study was to pinpoint a sustainable method on developing an evaluation checklist for teaching materials in the English language programmes. The answer of the main question is rejoined through three sub-questions about the sources for the checklist, identifying the design guidelines and offering a validation method for the developed checklist. Design-based research methodology was utilized through three main phases: analysis and exploration, design and construction and evaluation and reflection where the last phase comprised cycles of formative review of the developed checklist. The participants were purposefully sampled from the six Colleges of Applied Sciences in Oman and other higher education institutions. A report is written after each cycle of formative review (expert review, one –to-one, small group, and field testing) with the recommended changes which led to four revisions and redesigns of the checklist prototype. The results of this study were fourfold. First, a conceptual framework was designed that can be used to develop checklists for the evaluation of teaching materials in the English language programmes. Second, a verified checklist is developed that can be used as both an evaluation & selection instrument as well as a professional development tool. Third, formative review is perceived to be a powerful validation tool for reviewing the developed teaching materials evaluation checklists. Finally, guidelines on how to develop teaching materials evaluation checklists are yielded through the different phases of this study. The use of design-based research facilitated the design and the assessment of the checklist which indicates the necessity of such methodology in the complicated educational milieus with its focus on research, design and setting in unison. Besides the practical results, findings comprised adding new visualization of sources, content and use of teaching materials evaluation checklists. It is concluded that teaching materials evaluation is the main contributor to the students’ progression, the practitioners’ professional development and the success of the English language programmes as a whole.
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Pham, Truong Thuan Nguyen. "Multifunctional materials based on task-specific ionic liquids : from fundamental to next generation of hybrid electrochemical devices and artifical skin." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC218/document.
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Le développement durable nécessite des investissements massifs pour l'exploration et l'utilisation des sources d'énergie renouvelables dans le bilan énergétique. Parmi diverses formes de l’énergie, l'électricité est sans doute la forme la plus souhaitable pour les usages quotidiens. Cependant, en raison de l'intermittence des sources d’énergie renouvelables, l'électricité doit être stockée sous d'autres formes afin de corréler la production éphémère et la consommation en continue. Malgré la présence des systèmes commerciaux de stockage d'énergie, la recherche de nouveaux matériaux et de nouvelles approches pour résoudre ce problème est toujours en cours et attire également une grande attention. Les récents progrès ont poussé la communauté scientifique vers l'utilisation de matériaux à l'échelle nanométrique pour des systèmes de stockage et de conversion de l'énergie. Bien que ces derniers offrent des avantages pour réduire les émissions de gaz à effet de serre, leurs performances sont encore inférieures aux valeurs théoriques. Dans ce contexte, l’ingénierie à l'échelle moléculaire devient cruciale non seulement pour créer un nouveau type d'entités moléculaires mais aussi pour augmenter les performances des matériaux existants. Dans ce contexte, nous proposons d’utiliser une nouvelle famille de matériaux à base de liquides ioniques pour diverses d’applications, comprenant celles dans le domaine énergétique et pour le long terme, dans la fabrication de la peau artificielle, ces objectifs font l’objet de ces travaux de thèse. Cette dissertation est composée de cinq chapitres. Le chapitre 1 présente différents aspects des liquides ioniques (LIs) et des polymères à base de LI décrites dans la littérature. Via ce chapitre, nous envisageons d’atteindre les points suivants : (1) Décrire les utilisations possibles des liquides ioniques en électrochimie ; (2) Discuter des comportements physico-chimiques de ces composés en solution, (3) Montrer l'immobilisation de liquides ioniques (Redox-actifs) sur différents substrats : de couches minces aux polymères et (4) Mettre en évidence les travaux marquant portant sur l’utilisation des polymères ioniques liquides dans diverses applications. Le chapitre 2 présente différentes approches électrochimiques pour l'immobilisation de liquides ioniques rédox à la surface de l'électrode. De plus, les différentes caractéristiques des nouvelles interfaces seront reportées. Le chapitre 3 se concentre sur l'utilisation des polymères LIs comme catalyseurs émergents et comme matrices pour la génération de matériaux hybrides vers l'activation de petites molécules (ORR, OER, HER). Le chapitre 4 étudie la réactivité à l'échelle micro / nanométrique de divers matériaux, y compris les polymères liquides ioniques électro-actifs, en utilisant la microscopie électrochimique à balayage (SECM). Le chapitre 5 présente les résultats préliminaires de la fabrication de substrats flexibles avec des fonctionnalités intéressantes : possibilité de convertir le frottement en électricité et stockage d'énergie en utilisant des liquides ioniques redox polymériques. Ces études ouvrent de nouvelles opportunités pour élaborer des dispositifs flexibles, portables et implantables<br>Increasing demand of energy requires massive investment for exploration and utilization of renewable energy sources in the energy balance. However, due to the intermittence of the current renewable sources, the generated electricity must be stored under other forms to correlate the fleeting production and the continuous consumption. Despite available commercialized systems, seeking for new materials and new approaches for resolving this problem is still matter of interest for scientific researches. Highlighted advancements have recently oriented the community towards the utilization of nanoscale materials for efficient energy storage and conversion. Although the advantages given by existing nanomaterials for diverse applications, especially in the energy field, their performance is still lower than theoretical purposes. Consequently, tailoring the physical-chemical properties at the molecular scale becomes crucial not only for boosting the activities of the existed materials but also for creating a new type of molecular entities for storing and releasing the energy. Accordingly, this PhD work aim to develop new family of materials based on ionic liquid that exhibits a multifunctionality towards energy applications. Our work is based on the knowhow in surface functionalization and material preparation by simple methods to build up electrochemical systems that can be utilized in various applications. Thus, this thesis will report different results obtained by following this direction and is composed of six chapters: Chapter 1 reports an overview of ionic liquid and polymeric ionic liquid. We propose to review the available literature on the redox-IL from solution to immobilized substrates. Through this chapter, we will achieve the following points: (1) Report the possible uses of ionic liquids in electrochemistry; (2) Discuss about the physical-chemical behaviors of these compounds in solution, (3) Show the immobilization of (Redox-active)–ionic liquids onto different substrates: from thin layer to polymer and (4) Highlight recent advances using polymeric ionic liquids for diverse applications. Chapter 2 will be devoted to different electrochemical assisted approaches for the immobilization of (redox)-ionic liquids to the electrode surface. We will focus on generating a thin layer and polymeric film based ionic liquid. Furthermore, the different characteristics of the new interfaces will be reported. Chapter 3 concentrates on the use of the polymer ionic liquid modified electrodes as emerging catalyst and as template for the generation of hybrid materials towards activation of small molecules. Chapter 4 studies the reactivity at micro/nanometer scale of diverse materials, including single layer graphene, polymeric redox – ionic liquid, using the scanning electrochemical microscopy (SECM). Chapter 5 reports the potential applications of redox ionic liquid and focus on providing the preliminary results towards the fabrication of flexible substrates with interesting functionalities: possibility to convert the friction to electricity and energy storage by using polymeric redox ionic liquids. These studies open a new opportunity to elaborate flexible, wearable and implantable devices. Finally, some concluding remarks are given to summarize different results obtained in the previous chapters. Besides, different perspectives will be given by using ionic liquid as main material for developing different energy storage and conversion systems
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Khawaja, Mohamad. "Synthesis and Fabrication of Graphene/Conducting Polymer/Metal Oxide Nanocomposite Materials for Supercapacitor Applications." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5715.
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The rising energy consumption worldwide is leading to significant increases in energy production with fossil fuels being the major energy source. The negative environmental impact of fossil fuel use and its finite nature requires the use of alternative sources of energy. Solar energy is a clean alternative energy source; however, its intermittent nature is a major impediment that needs to be reduced or eliminated by the development of cost effective energy storage. Thermal storage in tanks filled typically with molten salt at elevated temperatures is widely used in concentrating solar power plants to generate electricity during periods of low daytime solar radiation or night time. Similarly, electrical storage in batteries, etc. is used in conjunction with photovoltaic solar power plants.
Electrochemical supercapacitors can be effectively used for electrical storage, either alone or in a hybrid configuration with batteries, for large scale energy storage as well as in electric vehicles and portable electronics. Unlike batteries’, supercapacitor electrodes can be made of materials that are either less toxic or biodegradable and can provide almost instantaneous power due to their unique charge storage mechanism similar to conventional capacitors found in most electronics. Unfortunately, the same storage mechanism prevents supercapacitors from having high energy density. The purpose of this dissertation is to investigate organic and inorganic electrode materials that can increase the specific capacitance and energy density of supercapacitors. Additionally, certain types of supercapacitor electrode materials store the charges at the electrode/electrolyte interface preventing any deformation of the material and thus increasing its cycle life by two to three orders of magnitude.
Transition metal oxides, layered transition metal chalcogenides, and their composites with graphene and conducting polymers have been synthesized, characterized, and their electrochemical performances evaluated for suitability as electrode materials for supercapacitor applications. Morphology and crystalline structure characterization methods used, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), were used throughout this work. Electrochemical characterization involved cyclic voltammetry (CV), constant current charge and discharge (CCCD), and electrochemical impedance spectroscopy (EIS) in two and three electrode configuration using aqueous and organic electrolytes.
Ruthenium oxide-graphene (RuO2-G) electrodes were tested in the two-electrode cell configuration and exhibit an areal capacitance of 187.5 mF cm-2 in 2M H2SO4 at a RuO2:G ratio of 10:1. Due to RuO2 high toxicity, scarcity, and high cost, manganese oxide-graphene (MnO-G) was used as an alternative but its low specific capacitance remains a major stumbling block.
The electrodes’ mass loading was studied in detail to understand the effects of thickness on the measured specific capacitance. Layered transition metal chalcogenides are structurally similar to graphene but possess different characteristics. Molybdenum sulfide (MoS2) is a two-dimensional material that has lower conductivity than graphene but larger sheet spacing making it easy for other materials to intercalate and form composites such as molybdenum sulfide-polyaniline (MoS2-PANI). MoS2-PANI electrodes, with different thicknesses, were measure in a three-electrode cell configuration resulting in gravimetric capacitance of 203 F g-1 for the thinnest electrode and areal capacitance of 358 mF cm-2 for the thickest electrode; all measurements performed using 1M H2SO4 aqueous electrolyte.
Attempts were also made to reduce the supercapacitor self-discharge by depositing on the electrode a blocking thin layer of barium strontium titanate (BST). The results were rather inconclusive because of the large thickness of the deposited BST layer. However, they strongly suggest that a very thin BST layer could improve the overall capacitance because of the very large dielectric constant of the BST material. Additional work is required to determine its effects on self-discharge.
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Liu, Jianfei. "Selective Deposition of Metallic and Semiconductor Materials onto DNA Templates for Nanofabrication." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3143.
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This work examines the selective deposition of metallic and semiconductor materials onto DNA templates for the fabrication of nanodevices. DNA origami provides a simple and robust method for folding DNA into a variety of shapes and patterns and makes it possible to create the complex templates needed for nanodevices, such as nanoelectronic circuits, plasmonics, and nanosensors. Metallization of DNA origami templates is essential for the fabrication of such nanodevices. In addition, selective deposition of semiconductor materials onto the DNA template is of importance for making many nanodevices such as nanocircuits. Metallization of DNA origami presents several challenges beyond those associated with the metallization of other DNA templates such as λ-DNA. All of these challenges were addressed in this study. DNA origami templates were seeded with Ag and then plated with Au via electroless deposition. Selective continuous metal deposition was achieved, with an average metallized height as small as 32 nm. The structure of T-shaped DNA origami was also retained after metallization. Following the metallization of complete origami, site-specific metallization of branched DNA origami was also demonstrated. To achieve this, staple strands at select locations on origami were replaced with staple strands modified with binding sites at the end. These binding sites then attached to thiolated DNA coated Au nanoparticles through base pairing. The continuous Au nanowires formed at designated sites on DNA origami after Au plating had an average width of 33 nm, with the smallest ones ~20 nm wide. The continuity of nanowires was verified by conductivity tests- the only tests of this nature of which I am aware. Moreover, predesigned sites on "circuit-shaped" DNA origami were successfully metallized. The selective deposition of a variety of materials onto DNA templates for the formation of continuous DNA-templated nanowires was also demonstrated. Specifically, an electroless Ni plating solution was developed to enable the fabrication of uniform and continuous DNA-templated Ni nanowires. Tests showed that these DNA-templated Ni nanowires were conductive. Moreover, continuous DNA-templated Bi2Te3 and/or Te nanowires have been fabricated through galvanic displacement of DNA-templated Ni and Cu nanowires. Altogether, these results represent important progress toward the realization of DNA-templated nanofabrication.
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Herlihy, Kevin Patrick DeSimone Joseph M. "Shape and size specific fabrication, characterization, and application of highly tailored biocompatible hydrogel particles for use in materials and biomedical settings /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2777.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2009.<br>Title from electronic title page (viewed Mar. 10, 2010). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry Polymer and Materials." Discipline: Chemistry; Department/School: Chemistry.
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Eggert, Björn. "Global English and Listening Materials : A Textbook Analysis." Thesis, Karlstad University, Karlstad University, Karlstad University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-4040.
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<p></p><p>This paper focuses on listening materials used in English language teaching in Sweden, especially in respect to the concept of global English. Global English could briefly be described as the linguistic, cultural, politic, and economic influence of English in the world. This influence concerns two aspects of English, namely the usage of English as a lingua franca in international communications, as well as the great range of English varieties that are used today. The purpose of this research is to study how varied listening materials are and how, when and why they are used in the classrooms. I conducted a two-part investigation to study these matters. The first part of the investigation focuses on teachers’ usage of listening materials and is based on a questionnaire handed out to five teachers. I found that the teachers varied much in their usage of listening materials. In the second part of the investigation I compare the listening materials provided by two Swedish textbooks on English, one from 1994 and one from 2003. Here I focus on the speakers’ varieties, rate of delivery, and instructions given for listening exercises. I found that both books featured a majority of speakers from the British Isles and America, and very few non-native speakers. The more recent book featured a larger degree of varieties outside the areas of Britain and the USA, as well as a larger degree of American English when dividing the varieties by the time these were spoken. RP (Received Pronunciation) and GA (General American) were also less dominating in the textbook from 2003. The rate of delivery was generally slower in the older textbook. The results from this investigation suggest that some changes seem to have occurred between the publishing of the two books. However, a focus on English as a lingua franca, where the aim is proficiency in efficient cross cultural communication rather than in the English spoken by native speakers, does not seem to have influenced the textbooks studied here. It is difficult to appreciate whether or not changes like these have taken hold in Swedish classrooms, as teachers use many different listening materials and in many different ways.</p><p> </p>
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Shekaran, Asha. "Beta 1 integrins in bone formation during development and engineering integrin-specific hydrogels for enhanced bone healing." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51720.
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Healing large bone defects remains a clinical challenge. While autografts are the gold standard treatment for large bone defects, they are limited by availability and donor site pain. Growth factor treatments such as BMP therapy provide a promising alternative but are expensive and present clinical safety concerns, primarily due to delivery of BMPs at supraphysiological doses. Integrins are ECM receptors which mediate crucial cell functions such as adhesion and differentiation. Therefore, understanding the role of integrins in bone formation and directing desired interactions may enable modulation of host cell functions for therapeutic applications. In this work, beta 1 integrins were deleted in osteolineage cells of transgenic mice at three different stages of differentiation to elucidate their role in bone development. We also engineered bioartificial PEG-based matrices which target the pro-osteogenic alpha 2 beta 1 integrin to promote bone healing. Conditional deletion of beta 1 integrins in osteochondroprogenitor cells under the Twist 2 promoter resulted in severe pre-natal skeletal mineralization defects and embryonic lethality. Targeted deletion of beta 1 integrins in osterix-expressing osteoprogenitors resulted in growth abnormalities, reduced calvarial mineralization, impaired femur development, and tooth defects. However, mice lacking beta 1 integrins in osteocalcin-expressing osteoblasts and osteocytes displayed only a mild skeletal phenotype, indicating that beta 1 integrins play an important role in early skeletal development, but are not required for mature osteoblast function. PEG hydrogels functionalized with the integrin-specific GFOGER ligand enhanced bone regeneration, induced defect bridging in combination with low doses of rhBMP-2 and stimulated improved bone healing compared collagen sponges, which are the clinical standard delivery vector for BMP-2 therapy. These results suggest that treatment with bioartificial integrin-specific PEG hydrogels may be a promising clinical strategy for bone regeneration in large bone defects.
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Bengtsson, Andreas. "Input and Learning Materials : An evaluation of dialogues in textbooks for Learners of Japanese." Thesis, Stockholms universitet, Avdelningen för japanska, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-82797.
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Karlsson, Maria. "Jämställda läromedel? : En studie om framställningen av kvinnor och män i läromedel för Svenska 1." Thesis, Linnéuniversitetet, Institutionen för svenska språket (SV), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-49849.
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The study aims to analyze whether two selected teaching materials intended for Swedish 1 published in 2014 and 2015 reflects the gender equality in Gy11. The study consists of a quantitative analysis and a discourse analysis that focus on how often and in what way women and men are depicted in the teaching material. The analyzed teaching materials are the textbooks Svenska 1 – helt enkelt and Fixa språket 1. The result shows that both books are quantitatively equal since men and women get almost as much space in the text and the image. However, the genders are depicted in different ways and constitute the norm in separate areas. The textbooks can even be said to be heteronormative. The result also shows that both textbooks raise gender equality issues, which should be seen as positive because education, according Gy11, should be characterized by a gender equality perspective.
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Madrid, Lozano Francesc. "Thermal Conductivity and Specific Heat Measurements for Power Electronics Packaging Materials. Effective Thermal Conductivity Steady State and Transient Thermal Parameter Identification Methods." Doctoral thesis, Universitat Autònoma de Barcelona, 2005. http://hdl.handle.net/10803/5348.
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Cora, Omer Necati. "DEVELOPMENT OF RAPID DIE WEAR TEST METHOD FOR ASSESSMENT OF DIE LIFE AND PERFORMANCE IN STAMPING OF ADVANCED/ULTRA HIGH STRENGTH STEEL (A/UHSS) SHEET MATERIALS." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/2003.
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Automotive companies are actively pursuing to increase the use of high-strength-lightweight alloys such as aluminum, magnesium, and advanced/ultra high-strength steels (A/UHSS) in body panel and structural part applications to achieve fuel efficiency while satisfying several environmental and safety concerns. A/UHSS sheet materials with higher strength and crashworthiness capabilities, in comparison to mild steel alloys, are considered as a near-term (i.e., ~5 years) choice of material for body and structural components due to their relatively low cost when compared with other lightweight materials such as aluminum and magnesium. However, A/UHSS materials present an increased level of die wear and springback in stamping operations when compared to the currently used mild steel alloys due to their higher surface hardness and high yield strength levels. In order to prevent the excessive wear effect in stamping dies, various countermeasures have been proposed such as alternative coatings, modified surface enhancements in addition to the use of newer die materials including cast, cold work tool, and powder metallurgical tool steels. In this study, a new die wear test method was developed and tested to provide a cost-effective solution for evaluating various combinations of newly developed die materials, coatings and surfaces accurately and rapidly. A new slider type of test system was developed to replicate the actual stamping conditions including the contact pressure state, sliding velocity level and continuous and fresh contact pairs (blank-die surfaces). Several alternative die materials in coated or uncoated conditions were tested against different AHSS sheet blanks under varying load, sliding velocity circumstances. Prior to and after wear tests, several measurements and tribological examinations were performed to obtain a quantified performance evaluation using commonly adapted wear models. Analyses showed that (1) the rapid wear method is feasible and results in reasonable wear assessments, (2) uncoated die materials are prone to expose severe form wear (galling, scoring, etc.) problems; (3) coated samples are unlikely to experience such excessive wear problems, as expected; (4) almost all of the the recently developed die materials (DC 53, Vancron 40, Vanadis 4) performed better when compared to conventional tool steel material AISI D2, and (5) in terms of coating type, die materials coated with thermal diffusion (TD) and chemical vapor deposition (CVD) coatings performed relatively better compared to other tested coating types; (6) It was seen that wear resistance correlated with substrate hardness.
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Campbell, Christopher. "The Effect of Pressure on Cathode Performance in the Lithium Sulfur Battery." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/312669.
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This study was undertaken to understand the effect of applied pressure on the performance of the lithium sulfur cathode. Compressible carbon based cathodes and novel nickel based cathodes were fabricated. For each cathode, pore volume and void volume were quantified and void fraction was calculated, compression under 0 to 2MPa was measured, and lithium-sulfur cells were assembled and cycled at pressures between 0 and 1MPa. The cathodes studied had void fractions in the range of 0.45 to 0.90. Specific discharge capacities between 200 and 1100 mAh/g under 1MPa were observed in carbon-based cathodes. Nickel-based cathodes showed increased specific discharge capacity of up to 1300 mAh/g, with no degradation of performance under pressure. The high correlation of specific discharge capacity and void fraction, in conjunction with previous work, strongly suggest that the performance of lithium-sulfur cathodes is highly dependent on properties that influence ionic mass transport in the cathode.
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Schlie, Sabrina. "Analysis of cell specific responses to polymers, hydrogels, metals, adhesion ligands, laser-fabricated three-dimensional scaffolds, and topographically-functionalized materials for biomedical applications." Hannover Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1001699750/34.
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Borg, Mathias. "Environmental Assessment of Materials, Components and Buildings Building Specific Considerations, Open-loop Recycling, Variations in Assessment Results and the Usage Phase of Buildings." Doctoral thesis, Stockholm : Tekniska högsk, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3232.
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Leinonen, Emma. "Language, Heteronormativity and Gender in EFL Teaching : Inclusion of Non-heteronormative Identities in Swedish EFL Materials and Classroom Practices." Thesis, Stockholms universitet, Engelska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-182669.
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The past few decades have seen a surge in awareness of issues related to both gender and sexual identity, which has shaped our understanding and use of these terms. However, there is a lag between awareness and practical changes, which can also be seen within education; teaching materials and practices change slowly, and the social and linguistic changes that are currently taking place are only partially visible in education. In the present study, gender and sexuality are approached from two perspectives: by analysing two EFL textbooks for upper secondary school and examining inclusive language use and representation of non-heteronormative identities, as well as by identifying attitudes and ideas expressed in interviews with three EFL teachers. The results show that LGBTQ+ representation is still scarce in these two textbooks; even though heterosexuality is not overtly reinforced in lexical choices, non-heteronormative relationships are not included. In addition, gender is still mostly portrayed as a binary, and gender issues are largely linked to male-female equality. In terms of the interviews, a general finding is that the participants are all aware of the importance of including and giving a voice to different gender and sexual identities when planning their teaching. However, deeply rooted traditions and the gender binary still play a role in how LGBTQ+ topics are perceived and addressed. Overall, it appears that teachers display more awareness and active inclusion of non-binary and non-heteronormative identities than what can be found in the textbooks.
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Yang, Hao. "Graphene-based Supercapacitors for Energy Storage Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376918924.
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Schlie, Sabrina [Verfasser]. "Analysis of cell specific responses to polymers, hydrogels, metals, adhesion ligands, laser-fabricated three-dimensional scaffolds, and topographically-functionalized materials for biomedical applications / Sabrina Schlie." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1001699750/34.
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Nordlén, Lisa. "The Journey from Innocence to Experience : Philip Pullman’s His Dark Materials as a female Bildungsroman." Thesis, Högskolan i Gävle, Institutionen för humaniora och samhällsvetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4396.
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In this essay the main aim is to consider Philip Pullman’s trilogy His Dark Materials with its female protagonist as a Bildungsroman. The principal source of the study is Jerome Buckley’s Season of Youth – The Bildungsroman from Dickens to Golding. Buckely’s presentation of the significant characteristics of the Bildungsroman will be applied to Philip Pullman’s His Dark Materials in order to explore if these characteristics are present, modified or not, in the trilogy. The second aim is to investigate how His Dark Materials relates to the patterns of the hero’s journey. In order to approach this question, Joseph Campbell’s work The Hero with a Thousand Faces is applied as a main source. Since most material concerning both the Bildungsroman and the hero’s journey are from a male point of view and concern males, the female perspective will be represented by Susan Fraiman and Linda Wagner who both write about females and the bildung narrative. In the section called The Story of Lyra, the trilogy is summarized briefly in order to give the reader a chance to understand what the trilogy is about. In the conclusion, Lyra’s development and (hero)-journey are discussed. The final claim of the study is that His Dark Materials can be considered a Bildungsroman and the patterns of the hero journey are found in the story about Lyra, but with some differences from her male counterparts.
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Signoret, Charles. "Valorisation de Matières Premières Secondaires (MPS) thermoplastiques en mélange issues de tri spectroscopique en ligne - Projet Mélanie MIR spectral characterization of plastic to enable discrimination in an industrial recycling context: I. Specific case of styrenic polymers MIR spectral characterization of plastic to enable discrimination in an industrial recycling context: II. Specific case of polyolefins." Thesis, IMT Mines Alès, 2019. http://www.theses.fr/2019EMAL0005.
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Les travaux de thèse présentés ici ont pour contexte le recyclage mécanique de polymères issus de DEEE (Déchets d’Equipements Electriques et Electroniques), principalement représentés par les styréniques (HIPS et ABS). Une première partie s’est intéressée à la discrimination de polymères par spectroscopie Infrarouge à Transformée de Fourier (IRTF ou FTIR), l’équivalent statique du MIR-HSI (Imagerie Hyperspectrale en Moyen-Infrarouge) qui pourrait être une réponse au verrou technologique du tri des plastiques sombres. Une quarantaine de références vierges de polymères (certaines vieillies en laboratoire), de charges minérales et de retardateurs de flamme ont été comparés à des gisements réels de DEEE pour établir une méthodologie d’identification, souligner des confusions possibles et mettre en valeur des signaux clefs.La recyclabilité d’ABS et d’HIPS a également été étudiée en reextrudant des échantillons modèles vieillis en conditions naturelles et artificielles à différentes durées. De fortes colorations suivies par photométrie, exclusivement des matières préalablement photooxydées, ont montré une importante réactivité en extrusion des espères formées lors du vieillissement. Les propriétés mécaniques, notamment statique en traction simple, dynamique en choc instrumenté mais également des essais rhéologiques en fondu ont, pour certains illustré la combinaison des deux phénomènes de dégradation.Le dernier aspect de ces travaux a concerné la gestion d’impuretés PP résiduelles au sein d’ABS après tri industriel imparfait. Sur des systèmes modèles, il a été constaté que les propriétés à l’impact commençaient à chuter dès 2% d’impuretés pour atteindre un minimum dès 4%. Des essais de compatibilisation ont permis de sélectionner le PP-g-MA et le SEBS comme agents de compatibilisation intéressants. Une modélisation prédictive des comportements jusqu’à rupture en statique basée sur des analyses morphologiques des mélanges de polymères (MEB et AFM) et des essais de traction instrumentés photomécaniquement a permis d’analyser la sensibilité des propriétés à rupture à la distribution des tailles de nodules de PP inhérente à l’emploi d’un compatibilisant<br>PhD works presented here were performed within the context of mechanical recycling of polymers recovered from WEEE (Waste Electrical and Electronic Equipment), mainly represented by styrenic polymers (HIPS and ABS). A first part focused on polymer discrimination thanks to Fourier-Transform Infrared spectroscopy (FTIR), the static equivalent of MIR-HSI (Mid-Infrared Hyperspectral Imagery) which could represent an answer to the technological obstacle of dark colored plastics sorting. About forty references of virgin polymers (some of them aged in laboratory), mineral fillers and flame retardants were compared to real WEEE waste stocks to establish an identification methodology, to highlight possible confusions and emphasize key signals.Recyclability of ABS and HIPS was studied by extruding model samples aged in both natural and artificial conditions at different durations. Strong discolorations monitored by photometry, exclusively for previously photooxydized materials, showed a strong reactivity during extrusion from species formed during ageing. Mechanical properties, including static ones through tensile tests, dynamic ones in instrumented impact and melted state rheology, showed, for some of them, an interaction between the two degradation phenomena.The last aspect of these works concerned the management of post-sorting residual PP impurities within ABS. With model systems, it was observed that impact properties began to fall at 2w% of impurities to reach a minimum at 4w%. Compatibilization trials lead to the selection of PP-g-MA and SEBS as interesting compatibilizers. Predictive modeling of static behavior towards failure, based on morphological analysis of polymer blends (SEM and AFM) and photomecanically instrumented tensile tests, highlighted the sensitivity of break properties to the distribution of PP nodules sizes under the influence of a compatibilize
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Banjara, Shree Ram. "STUDY OF ADSORPTION OF CARBON DIOXIDE ON CARBON BASED NANO-MATERIALS AND EVALUATION OF ISOSTERIC HEAT, SPECIFIC EFFECTIVE SURFACE AREA AVAILABLE FOR ADSORPTION AND ADSORPTION KINETICS." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/915.
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Single-walled dahlia-like carbon nanohorns treated with H2O2 for 3hrs at 150 ℃ were used as sorbent in a study of CO2 adsorption. This treatment ensures that the nanohorns are open and they have their interior space available for adsorption. Volumetric adsorption measurements on open spherical aggregates of dahlia-like single walled carbon nanohorns were performed at seven different temperatures between 158.66 K and 208.68 K. The waiting time for reaching the equilibrium pressure after adding a dose increased with sorbent loading. Unlike Ne and CF4 adsorption isotherms measured on similar substrate which have two distinct substeps present in the isotherms, the adsorption data for CO2 has a single very broad step present between the lowest coverage and saturation. Results for the loading dependence of the isosteric heat indicate that this quantity depends non-monotonically on the amount of CO2 adsorbed. The effective specific surface area of the open single walled carbon nanohorns sample obtained in this study are compared with the ones obtained with other carbon nanohorn samples; the results clearly indicate that nanohorns are open.