Дисертації з теми "Materials science as a profession"
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Biggers, Mandy Sue. "Elementary teachers' ideas about, planning for, and implementation of learner-directed and teacher-directed inquiry: a mixed methods study." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/2438.
Повний текст джерелаBarker, Joanna. "Evaluating clinical competence in a health science profession." Thesis, Barker, Joanna (1987) Evaluating clinical competence in a health science profession. PhD thesis, Murdoch University, 1987. https://researchrepository.murdoch.edu.au/id/eprint/52158/.
Повний текст джерелаRose, Sharon L. "Isaac Asimov's Profession : a Burkeian criticism." Virtual Press, 1990. http://liblink.bsu.edu/uhtbin/catkey/722234.
Повний текст джерелаDepartment of Speech Communication
Rigné, Eva Marie. "Profession, science and state : Psychology in Sweden 1968-1990." Doctoral thesis, Sociologiska institutionen, Göteborgs universitet, Göteborg, Sweden, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51556.
Повний текст джерелаRigné, E. M. "Profession, science and State : psychology in Sweden, 1968-1990 /." Göteborg : Göteborg university, 2002. http://catalogue.bnf.fr/ark:/12148/cb39070067b.
Повний текст джерелаNyström, Alexandra, and Felix Dürango. "Optimization of Assembly Material Feeding : at Electrolux Professional AB." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42325.
Повний текст джерелаMutlu, Neset. "The Design And Development Of An Online Professional Development Material For Science And Technology Teachers On Assessment And Evaluation." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615179/index.pdf.
Повний текст джерелаperceptions and attitudes towards prototypes, semi-structured interview schedule, Internet Tutorial Attitude Questionnaire, and a Checklist for Product Evaluation was conducted to 21 science and technology teachers in total. These data were analyzed using both qualitative and quantitative methods to reveal considerations of science and technology teachers about these prototypes and to make adjustments on these prototypes accordingly. In second part, final version of this material was evaluated. In this phase, researcher used self-efficacy questionnaire about alternative assessment and evaluation methods and a checklist for material validation. These instruments were administered both before and after use of final version of online professional development material. Descriptive data analysis was conducted to reveal differences in participants&rsquo
perceived-knowledge, beliefs, and applications about alternative assessment and evaluation methods after use of online professional development material. Research results disclosed participants&rsquo
beliefs and attitudes towards content, design and usability issues of online professional development material. Besides, validation of online professional development material revealed positive changes in participants&rsquo
perceived-knowledge, their classroom practices, self-efficacy beliefs and their perceptions about appropriateness of alternative assessment methods&rsquo
usage in classroom.
Ogwuda, Olisanwendu Ikechukwuka. "Materials science appraisal of recycled construction materials for roadways." Thesis, Abertay University, 2007. https://rke.abertay.ac.uk/en/studentTheses/70d295b3-60d9-427e-a012-c9cc05ac83e1.
Повний текст джерелаSwedling, Daniel. "Gränslandet mellan byråkrati och profession : Samarbetet i sjukpenningärenden." Thesis, Uppsala universitet, Statsvetenskapliga institutionen, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446684.
Повний текст джерелаForclaz, A. "Variational methods in materials science." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249532.
Повний текст джерелаRouet-Leduc, Bertrand. "Machine learning for materials science." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267987.
Повний текст джерелаHartmann, Markus. "Lattice models in materials science." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2006. http://dx.doi.org/10.18452/15432.
Повний текст джерелаThis thesis presents the results of investigations on three independent research topics of modern biophysical and materials science research: substitutional diffusion in binary alloys, the remodelling process in trabecular bone and the prediction of mechanical properties of self assembling, amphiphilic bilayers. The basic description of all three projects is based on lattice models, a highly successful class of models that are used in several fields of modern physics to describe physical processes. For the diffusional process in alloys, which on a microscopic scale manifests in a discrete site exchange between one atom and a neighbouring vacancy, it was investigated how this microscopic description can be reconciled with a macroscopic continuum model. For the investigations on remodelling of trabecular bone, the architecture of bone was mapped onto a lattice and the local mechanical state of each element was determined by a simplified mechanical model. A stochastic description was chosen to model the time evolution of the system, relating the probability of bone formation and resorption, respectively, to the local volume changes of the bone elements. It was shown that a non-linear remodelling law is a better candidate to describe the remodelling process in real bone than a linear one. Furthermore, applying the model to osteoporosis - a wide spread bone disease - it was shown that in the features attributed to osteoporosis one has to distinguish between normal ageing of bone''s architecture and additional changes that stem from pathological alterations in the regulatory system. A simple concept was introduced to model the mechanical properties of self-assembled membranes. The molecules forming the membrane are assumed to occupy a triangular lattice, nearest neighbours are connected by linear elastic springs. It was shown that the bending rigidity exhibits a pronounced concentration dependence, varying over orders of magnitude in a narrow concentration regime.
Maguire, John F. "Contributions to materials science and engineering." Thesis, Ulster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515891.
Повний текст джерелаStoleriu, Iulian. "Integro-differential equations in materials science." Thesis, University of Strathclyde, 2001. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21413.
Повний текст джерелаSchuster, Kristen M. "A Sequential Exploratory Mixed Methods Study of Carnegie Libraries and the Library Profession, 1900-1910." Thesis, University of Missouri - Columbia, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10629018.
Повний текст джерелаAndrew Carnegie’s philanthropy made it possible for thousands of communities in the United States (U.S) to build free public libraries. Contemporary scholarship in library and information science (LIS) that deals with Carnegie’s philanthropy tends to place emphasis on generalized historical ideals associated with the construction of public libraries. As a result, it often fails to critically inquire into the relationships between the work performed by librarians and assumptions about the cultural value of Carnegie libraries. This dissertation investigates broad trends in library history in order to better understand the particular experiences of fifteen Midwestern communities that built public libraries with Andrew Carnegie’s money in the first decade of 20 th century. Mixed methods research supports the synthesis of broad qualitative data with specific quantitative data, which supports assessments of primary sources in relation to scholarship about the library profession and Carnegie’s philanthropy. Comparing and contrasting findings from two distinct data sets makes it possible to discuss idiosyncrasies architectural trends and to better understand the role professional rhetoric played in their development within a specific geographic region (the Midwest).
Jansson, Hampus. "Journalistikens professionalisering och mediernas demokratiska roll? : En studie av journalistyrket som profession." Thesis, Linnéuniversitetet, Institutionen för statsvetenskap (ST), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65321.
Повний текст джерелаAl-Rashed, Wael E. R. "Kuwait's tax reformation, its alternatives and impact on a developing accounting profession." Thesis, University of Hull, 1989. http://hydra.hull.ac.uk/resources/hull:3573.
Повний текст джерелаBauer, Uwe Ph D. Massachusetts Institute of Technology. "Voltage programmable materials." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/98317.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 211-223).
The physical and chemical properties of nanoscale materials derive largely from structure and composition at interfaces. The possibility to electrically modify these interfacial characteristics would provide a powerful means to control material properties. Of particular recent scientific and technological interest are metal/metal-oxide bilayers, in which properties as varied as catalytic activity, charge and spin transport, ionic exchange, mechanical behavior, thermal conductivity, and magnetism all depend sensitively on oxygen stoichiometry and defect structure at the metal/metal-oxide interface. The possibility to dynamically control interface characteristics through electric-field-induced oxygen transport and electrochemical interface reactions paves the way towards voltage control of these properties in solid-state devices. Here, we focus on ferromagnetic metal/metal-oxide bilayers that exhibit strong perpendicular magnetic anisotropy derived from interfacial oxygen hybridization. In these materials, we directly observe, in situ voltage-driven oxygen migration at room temperature and show that electrical switching of the interfacial oxidation state allows for voltage control of magnetic properties to an extent never before achieved through conventional magneto-electric coupling mechanisms. By engineering the electrode and metal-oxide layers for efficient ionic exchange and transport, we improve the response time by six orders of magnitude and switch perpendicular magnetic anisotropy at the millisecond timescale. Based on this magneto-ionic coupling mechanism we demonstrate a printer-like system to reversible pattern magnetic properties and realize a prototype nonvolatile memory device in which voltage-controlled domain wall traps facilitate electrical bit selection in a magnetic nanowire register. Moreover, we report on voltage control over electronic transport properties in the same bilayer structures and show that solid-state switching of interface oxygen chemistry provides a path towards voltage-gating the wide range of phenomena governed by metal/oxide interfaces.
by Uwe Bauer.
Ph. D.
Bryan, David Jeffrey. "Development of a Burn-Resistant Titanium Alloy Through the Laser Deposition of Elementally Blended Powders." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391597767.
Повний текст джерелаVempati, Vamsi Krishna. "ISOTHERMAL DEFORMATION AND MODELING OF Ti-6Al-4V." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341865463.
Повний текст джерелаLevkulich, Nathan Charles. "An Experimental Investigation of Residual Stress Development during Selective Laser Melting of Ti-6Al-4V." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1515112797193544.
Повний текст джерелаYang, Jianping. "Synthesis and Characterizations of Lithium Aluminum Titanium Phosphate (Li1+xAlxTi2-x(PO4)3) Solid Electrolytes for All-Solid-State Li-ion Batteries." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright151550285784082.
Повний текст джерелаWang, Menghong. "Degradation of Photovoltaic Packaging Materials and Power Output of Photovoltaic Systems: Scaling up Materials Science with Data Science." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1595416965256375.
Повний текст джерелаLópez, Conesa Lluís. "Advanced TEM imaging tools for materials science." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/395195.
Повний текст джерелаLa reducció en l'escala espacial associada a la revolució de la Nanociència i la Nanotecnologia fa necessari comptar amb una sèrie d'eines capaces d'assolir una resolució sense precedents en una gran varietat d'àress, ja no tan sols com a control de qualitat, sinó per tal d'entendre les propietats de la matèria a la nanoescala. La correlació de la configuració estructural, la composició química i les distribucions de càrrega amb les propietats funcionals és imprescindible pel disseny de nous dispositius, tant des de la perspectiva 'top down' (reducció de les dimensions dels dispositius) com de la perspectiva 'bottom up' (fabricació d'estructures complexes a partir de blocs més petits, fins i tot àtoms). La capacitat de la Microscòpia Electrònica de Transmissió (TEM) de proporcionar diferents tipus d'informació amb una alta resolució espacial, situa les tècniques avançades de TEM com a peça clau en el desenvolupament d'aquest camp multidisciplinari i creixent. L'objectiu principal d'aquesta tesi ha estat l'aplicació de tècniques quantitatives d'imatge TEM per la resolució de problemes en ciència dels materials. La tesi cobreix un espectre ampli pel que fa al tipus de materials estudiats i els seus camps d'aplicació. El Capítol 1 presenta una introducció general a la teoria de formació d'imatge aplicada a la microscopia TEM. S'hi exposen els diferents fenòmens d'interacció electró-matèria que són responsables dels diferents tipus de contrast que es poden trobar a les imatges TEM. El Capítol 2 presenta les tècniques experimentals que es faran servir en la caracterització dels materials, en concret la simulació d'imatges d'alta resolució (HRTEM), l'holografia electrònica i l'anàlisi de la fase geomètrica (GPA). S'hi pot trobar una descripció del marc teòric i dels fonaments experimentals, juntament amb un resum dels resultats més recents en aquests camps. Els resultats experimentals s'agrupen en els capítols posteriors segons la dimensionalitat dels sistemes estudiats. En ordre decreixent de dimensionalitat s'hi inclouen: materials massius (3D), capes primes (2D), nanofils (1D) i nanopartícules (1D).
Osorio, Guillén Jorge Mario. "Density Functional Theory in Computational Materials Science." Doctoral thesis, Uppsala University, Department of Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4496.
Повний текст джерелаThe present thesis is concerned to the application of first-principles self-consistent total-energy calculations within the density functional theory on different topics in materials science.
Crystallographic phase-transitions under high-pressure has been study for TiO2, FeI2, Fe3O4, Ti, the heavy alkali metals Cs and Rb, and C3N4. A new high-pressure polymorph of TiO2 has been discovered, this new polymorph has an orthorhombic OI (Pbca) crystal structure, which is predicted theoretically for the pressure range 50 to 100 GPa. Also, the crystal structures of Cs and Rb metals have been studied under high compressions. Our results confirm the recent high-pressure experimental observations of new complex crystal structures for the Cs-III and Rb-III phases. Thus, it is now certain that the famous isostructural phase transition in Cs is rather a new crystallographic phase transition.
The elastic properties of the new superconductor MgB2 and Al-doped MgB2 have been investigated. Values of all independent elastic constants (c11, c12, c13, c33, and c55) as well as bulk moduli in the a and c directions (Ba and Bc respectively) are predicted. Our analysis suggests that the high anisotropy of the calculated elastic moduli is a strong indication that MgB2 should be rather brittle. Al doping decreases the elastic anisotropy of MgB2 in the a and c directions, but, it will not change the brittle behaviour of the material considerably.
The three most relevant battery properties, namely average voltage, energy density and specific energy, as well as the electronic structure of the Li/LixMPO4 systems, where M is either Fe, Mn, or Co have been calculated. The mixing between Fe and Mn in these materials is also examined. Our calculated values for these properties are in good agreement with recent experimental values. Further insight is gained from the electronic density of states of these materials, through which conclusions about the physical properties of the various phases are made.
The electronic and magnetic properties of the dilute magnetic semiconductor Mn-doped ZnO has been calculated. We have found that for an Mn concentration of 5.6%, the ferromagnetic configuration is energetically stable in comparison to the antiferromgnetic one. A half-metallic electronic structure is calculated by the GGA approximation, where Mn ions are in a divalent state leading to a total magnetic moment of 5 μB per Mn atom.
Ghafoor, Naureen. "Materials Science of Multilayer X-ray Mirrors." Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11343.
Повний текст джерелаDenna avhandling behandlar syntes, analys, och materialvetenskap rörande så kallade multilagerspeglar för mjuk röntgenstrålning. Speglarna är lämpade som optiska komponenter för instrument såsom röntgenmikroskop i våglängdsområdet 2,4 nm till 4,4 nm, även kallat vattenfönstret. Tack vare de senaste decenniernas stora teknologiska och vetenskapliga framsteg i att framställa mycket intensiva källor för mjuk röntgenstrålning, såsom tex synkrotronljuskällor, frielektronlasrar, och plasmagenererade källor, är det nu tänkbart att utnyttja denna strålning till nya tillämpningar som tidigare inte varit möjliga. Några exempel är; röntgenmikroskopi av biologiska preparat med upplösning ca 1/100 av det som är möjligt med synligt ljus, fotolitografi av Det finns flera stora utmaningar för att lyckas tillverka multilagerspeglar. Först och främst måste man hitta materialkombinationer som ger upphov till reflektion i mellanytorna mellan materialen men som inte samtidigt absorberar all röntgenstrålning. Dessutom måste materialen gå att belägga på varandra i flera hundra tunna lager, vart och ett endast ca 1 nanometer tjockt, med en ytojämnhet om endast några tiondels nanometer. Den absoluta tjockleks precision i varje I det här arbetet har fyra olika typer av multilagerbeläggningar undersökts: krom/titan (Cr/Ti), krom/skandium (Cr/Sc), nickel/vanadin (Ni/V) samt kromnitrid/skandiumnitrid (CrN/ScN). Materialvalen har baserats på teoretiska beräkningar som visat att dessa materialsystem genererar mycket god reflektans i vattenfönstret. Varje kombination av metaller är optimal för en specifik våglängd och de individuella lagertjocklekarna måste optimeras teoretiskt för varje enskilt För Cr/Sc multilager har vi visat att lagren som beläggs har en oordnad, så kallad amorf, struktur mellan metallatomerna som har sitt ursprung i att multilagrets totala energi kan sänkas om mellanytor mellan kristallint Cr och kristallint Sc kan undvikas. Studier av effekterna av kväveupptag hos Cr/Sc multilagerspeglar under sputtringsprocessen har lett till ökad förståelse av materialsystemet. Till exempel har vi visat att kvävet framförallt binder till de inre regionerna av Sc och inte så mycket till Cr-lagren eller i mellanytorna. Med kväve i strukturen har vi gjort speglar som tål höga temperaturer, vilket är av stor betydelse för tillämpningar baserade högintensiva ljuskällor. Så kallade supergitter, dvs multilager
Osorio, Guillén Jorge Mario. "Density functional theory in computational materials science /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4496.
Повний текст джерелаKapadia, Rasesh Dilranjan. "Applications of NMR imaging in materials science." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055794721.
Повний текст джерелаCARONE, FABIANI FILIPPO. "Adsorbption and scattering phenomena in materials science." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/50846.
Повний текст джерелаLokander, Mattias. "Performance of Magnetorheological Rubber Materials." Doctoral thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31.
Повний текст джерелаMagnetorheological (MR) rubber materials are the solid analogue of magnetorheological fluids; i.e. their rheological properties can be controlled continously, rapidly, and reversibly by an applied magnetic field. They consist of magnetically polarisable particles in an elastomer matrix and they can be made to respond to changes in their environment; hence, they are considered as "smart" materials. Examples of potential applications for these materials are adaptive tuned vibration absorbers, stiffness-tuneable mounts and suspensions, and automotive bushings.
The purpose of this work was to increase the knowledge relating to magnetorheological materials for damping applications. The materials should exhibit a large response to an applied magnetic field, and have good mechanical and long-term properties.
MR rubber materials were made from nitrile, natural and silicone rubber, with irregularly shaped iron particles several micrometres in size. The particles were not aligned by a magnetic field prior to the vulcanisation; hence, the materials can be considered to be isotropic. These materials show a large MR effect, i.e. an increase in the shear modulus when a magnetic field is applied, although the particles are not aligned within the material. This is explained by the low critical particle volume concentration (CPVC) of such particles. Similar behaviour can be obtained with materials containing carbonyl iron, if the particles are aggregated so that they behave like large irregular particles. The iron particle concentration must be very close to the CPVC in order to obtain a large MR effect without alignment of the particles.
The absolute MR effect (MPa) in an isotropic MR rubber material with large irregular iron particles is independent of the matrix material, and the relative MR effect (%) can thus be increased by the addition of plasticisers. However, the obtainable effect is limited by the reinforcement of the particles and by friction between the particles. Therefore, it is very difficult, if not impossible, to achieve an MR effect larger than 60%.
Other ways of increasing the MR effect are to increase the strength of the magnetic field, although the materials saturate magnetically at high field strengths, or to use small strain amplitudes. The strong strain amplitude dependence of the MR effect suggests that MR rubber materials are most suitable for low amplitude applications, such as sound and vibration insulation. Measurements at frequencies within the audible frequency range show that this is a promising application for MR rubber materials.
The incorporation of large amounts of iron into the rubber matrix decreases the oxidative stability dramatically. This is probably due to iron oxides on the surface of the particles, and to the fact that the oxidation rate is enhanced by iron ions, which are able to diffuse into the matrix. Standard antioxidants do not provide sufficient stabilisation for MR rubbers. Thus, proper stabilisation systems have to be found in order for these materials to be successful in applications.
Sagar, Ambuj Daya. "Materials separation by dielectrophoresis." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14215.
Повний текст джерелаKrasnow, Nicholas Riordan. "Antimicrobial Copper Iodide Materials." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612146.
Повний текст джерелаMalan, Mareta. "Novel materials for VOC analysis." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71646.
Повний текст джерелаENGLISH ABSTRACT: The need to analyse and detect volatile organic compounds (VOCs) at trace levels has led to the development of specialized sample preparation techniques. The requirement for trace analysis of VOCs stems from the negative effects they have on the environmental and human health. Methods for the analysis of non-polar VOCs commonly found as trace contaminants in water and analysis of more polar oxygenated compounds commonly found in zero-VOC water-based paints were developed. Solid phase micro extraction (SPME) was employed and extraction of the majority of the target analytes could be achieved at levels below 0.3 μg.l-1. In an attempt to further improve the detection of these two target analyte groups, novel materials based on poly(dimethyl siloxane) (PDMS) were investigated as possible extraction phases for VOCs, with the focus specifically on the analysis of the polar analytes in paint. Conventional free radical polymerization was used to synthesize poly(methyl methacrylate-graft-poly(dimethyl siloxane) (PMMA-g-PDMS), poly(methacrylic acid)-graft-poly(dimethyl siloxane) (PMAA-g-PDMS), polystyrene-graftpoly( dimethyl siloxane) (PSty-g-PDMS) and poly(butyl acrylate)-graft–poly(dimethyl siloxane) (PBA-g-PDMS). These polymers have a copolymer functionality which presents a series of different polarities. The MMA-g-PDMS and MAA-g-PDMS as well as the homopolymers were electrospun into nanofibers. The low glass transition temperature and molecular weight of the PBAg- PDMS meant that this polymer could not be electrospun. Scanning electron microscopy (SEM) was used to study the fiber morphology of the electrospun fibers and the non-beaded fibers were further investigated. Polyacrylonitrile-graft-poly(dimethyl siloxane) (PAN-g-PDMS) previously synthesized and electrospun by another member of the group were also investigated for use as possible extraction material in volatile analysis. The thermal stability of the nanofibers at 200°C was studied using thermal gravimetric analysis (TGA). This property is important since after the target analytes are extracted using the nanofibers, elevated temperatures are used to thermally desorp the volatile analytes from the extraction materials prior to GC analysis. The PAN-g-PDMS, MMA-g-PDMS and PMMA showed no significant weight loss during thermal evaluation, however, it was observed that the PMMA and PMMA-g-PDMS nanofibers looses their nanostructure and that the PAN-g-PDMS nanofibers changes colour from white to yellow to rust brown. The polymers based on MAA showed weight losses of more than 10% after one hour of exposure to the elevated temperatures, but the nanostructure remained intact. The PAN-g-PDMS, PMAA-g-PDMS and PMAA nanofibers were evaluated as possible extraction materials for VOC analysis. The nanofibers were evaluated using a similar approach to that of stir bar sorptive extraction (SBSE). Headspace sorptive extraction (HSSE) using a commercially available PDMS stir bar and the novel materials were used to evaluate the extraction efficiency of the different materials. The optimized extraction method developed using SPME were employed for the extraction using the nanofibers and PDMS stir bar. It was noted that the nanofibers lose their extraction capabilities during the first extraction/desorption cycle possibly due to thermal degradation therefore each of the materials can only be used in a single extraction. The majority of the non-polar analytes were extracted using the nanofibers at levels of 500 μg.l-1, however it was noted that the commercially available SPME extraction materials and the PDMS stir bar had superior extraction efficiencies for the specific target analytes. In the evaluation of the nanofibers for extraction of the more polar oxygenated analytes it was noted that 2-Ethylhexylacrylate was the only analyte to be extracted by all of the materials. The PAN-g-PDMS extracted three of the four analytes at levels of 100 μg.l-1. At lower analyte concentrations of 10 μg.l-1 only two of the four acrylate compounds were detected using the PAN-g-PDMS nanofibers. Ethyl acrylate was not extracted by any of the novel materials, whereas in SPME using the CAR/PDMS fiber, the LOD was determined to be below 1 μg.l-1. Although these materials were not superior to the commercially available phases, this is only the case for the specific target analytes analyzed.
AFRIKAANSE OPSOMMING: Die behoefte vir die analiese van vlugtige organiese verbindings (VOS) op spoorvlak, het gelei tot die ontwikkeling van gespesialiseerde monster voorbereidingstegnieke. Die vereiste vir die spoor analiese van die VOS het ontstaan uit die negatiewe uitwerking wat hierdie stowwe het op die omgewing en menslike gesondheid. Metodes vir die analiese van nie-polêre VOS wat algemeen voorkom as spoorkontaminante in water en polêre suurstofryke verbindings wat algemeen voorkom in nul-VOS water-gebaseerde verf was ontwikkel. Soliede fase mikro-ekstraksie (SFME) was gebruik, en die ekstraksie van die meerderheid van die teikenstowwe kon gedoen word op vlakke laer as 0,3 μg.l-1. In 'n poging om die opsporing van hierdie twee teiken analietgroepe verder te verbeter, is nuwe materiale gebaseer op polidimetielsiloksaan (PDMS), ondersoek as moontlik ekstraksiefases vir VOS, met die fokus spesifiek op die analiese van die polêre stowwe in verf. ’n Konvensionele vrye radikaal polimerisasieproses was gebruik om poli (metiel- metakrilaat)-entpoli( dimetielsiloksaan) (PMMA-g-PDMS), poli(metakrilaatsuur)-ent–poli (dimetielsiloksaan) (PMAA-g-PDMS), polistireen-ent-poli(dimetielsiloksaan) (PSty-g-PDMS) en poli(butielakrilaat)- ent-poli(dimetielsiloksaan) (PBA-g-PDMS) te sintetiseer. Hierdie ko-polimere het 'n kopolimeer funksionaliteit wat 'n reeks van verskillende polariteite bied. Die MMA-g-PDMS en MAA-g-PDMS sowel as die homopolimere was ge-elektrospin in orde om nanovesels te vorm. Die lae glasoorgangstemperatuur en molekulêre gewig van die PBA-g-PDMS het beteken dat hierdie polimeer nie elektrospin kon word nie. Skandeerelektronmikroskopie (SEM) was gebruik om die veselmorfologie van die ge-elektrospinde vesels te bestudeer en die nanovesels wat ’n eweredige oppervlak gehad het, was verder ondersoek. Poliakrilonitriel-ent-poli(dimetielsiloksaan) (PAN-g- PDMS) wat voorheen gesintetiseer en ge-elektrospin was deur 'n ander lid van die groep is ook ondersoek vir gebruik as moontlik ekstraksiemateriaal vir die analiese van vlugtige stowwe. Die termiese stabiliteit van die nanovesels was by 200°C bestudeer met behulp van ‘n termiese gravimetriese analiese (TGA) instrument. Hierdie eienskap is belangrik, aangesien die teikenstowwe by hoë temperature van die nanovesels gedesorbeer word voor die GC-analiese. Die PAN-g-PDMS, MMA-g-PDMS en PMMA het geen beduidende gewigsverlies tydens termiese evaluering gehad nie, alhoewel dit egter waargeneem was dat die PMMA en PMMA-g-PDMS nanovesels hulle nanostruktuur verloor en dat die PAN-g-PDMS nanovesels se kleur verander van wit na geel na roesbruin gedurende die termiese analiese. Die polimere wat gebaseer was op MAA het ’n gewigs-verlies van meer as 10% getoon na 'n uur van blootstelling aan die verhoogde temperature, maar die nanostruktuur het ongeskonde gebly. Die PAN-g-PDMS, PMAA-g-PDMS en PMAA nanovesels was geëvalueer as moontlike ekstraksiemateriale vir VOS-analiese. Die nanovesels was geëvalueer met 'n soortgelyke benadering tot dié van “stir bar“ sorpsie ekstraksie (SBSE). Bo-ruimte sorpsie ekstrasie is gebruik om die ekstraksie-doeltreffendheid van die verskillende materiale (kommersiële PDMS en nanovesels) te evalueer. Die geoptimaliseerde ekstraksiemetode ontwikkel in SFME was gebruik vir die ekstraksie van die VOS met die nanovesels en die PDMS “stir bar“. Dit was waargeneem dat die nanovesels hul ekstraksievermoë verloor tydens die eerste ekstraksie/desorpsie siklus, moontlik as gevolg van termiese degradasie dus, kon die materiale slegs ‘n enkele maal gebruik word vir die ekstraksie. Die meerderheid van die nie-polêre stowwe was ge-ëkstraeer deur gebruik te maak van die nanovesels op vlakke van 500 μg.l -1, maar die kommersieel beskikbare SFME ekstraksie materiale en die PDMS “stir bar“ se ekstraksie-doeltreffendheid vir die spesifieke stowwe was beter. In die evaluering van die nanovesels vir die ekstraksie van die meer polêre suurstofryke stowwe was daar waargeneem dat 2- etielheksielakrilaat die enigste analiet was wat ge-ëkstraeer was deur al die materiale. Die PAN-g- PDMS kon drie van die vier polêre stowwe op vlakke van 100 μg.l-1 opspoor. By laer analietkonsentrasies van 10 μg.l-1 kon slegs twee van die vier akrilaat verbindings opgespoor word deur gebruik te maak van hierdie nanovesels. Etielakrilaat was nie ge-ëkstraeer deur enige van die nuwe materiale nie, terwyl in SFME met die gebruik van die CAR/ PDMS vesel, die analiet op vlakke onder 1 μg.l-1 opgespoor kon word. Alhoewel hierdie nuwe materiale nie beter is as die kommersieel beskikbare ekstraksiemateriale nie is dit net die geval vir die spesifieke teiken analietgroepe wat ondersoek was in hierdie studie.
Zhu, Fuyou. "Advanced materials for composite armour." Thesis, Queen Mary, University of London, 2009. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1775.
Повний текст джерелаTolley-Stokes, Rebecca, and Carol Smallwood. "Mentoring in Librarianship: Essays on Working with Adults and Students to Further the Profession." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu_books/196.
Повний текст джерелаYoak, Beth A. "Rapid Nailing Method for Joining Materials." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397604720.
Повний текст джерелаNugent, Thomas J. (Thomas Joseph) 1971. "Spherical indentation of magnetostrictive materials." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85369.
Повний текст джерелаChoi, In-Suk Ph D. Massachusetts Institute of Technology. "Indentation of plastically graded materials." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38587.
Повний текст джерелаIncludes bibliographical references (p. 115-126).
The introduction of certain controlled gradients in plastic properties is known to promote resistance to the onset of damage at contact surfaces during some tribological applications. Gradients in composition, microstructure and plastic properties can also be deleterious to contact-damage resistance in some situations. In order to realize such potentially beneficial or deleterious effects of plastic property gradients in tribological applications, it is essential first to develop a comprehensive understanding of the effects of yield strength and strain hardening exponent on frictionless normal indentation. To date, however, systematic studies of plasticity gradient effects on indentation response have not been completed. A comprehensive parametric study of the mechanics of indentation of plastically graded materials is completed in this work by recourse to finite element (FE) computations. On the basis of a large number of detailed computational simulations, a general methodology for assessing instrumented indentation response of plastically graded materials is formulated so that quantitative interpretations of depth-sensing indentation experiments could be performed. The specific case of linear gradient in yield strength is explored in detail.
(cont.) The FE analysis leads to a universal dimensionless function to predict load displacement curves for plastically graded engineering materials. Experimental validation of the analysis is performed by choosing the model system of an electrodeposited nanostructured Ni-W alloy, where the plastic property variation is introduced through a linear variation in grain size with distance through the thickness. The universal dimensionless function is shown to correlate with the shield factor which is used to predict crack behavior at the interface of plastically graded materials. Here in this work a general framework is proposed for the indentation of plastically graded materials based on energetic considerations. Possible mechanisms underlying indentation size effects are also explored including the surface energy terms in the proposed energy based framework so as to rationalize a broad range of experimental observations. Practical implications of the present work are highlighted.
by In-Suk Choi.
Ph.D.
Paramonova, Ekaterina (Ekaterina D. ). "CRUD resistant fuel cladding materials." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82447.
Повний текст джерела"June 2013." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 27-29).
CRUD is a term commonly used to describe deposited corrosion products that form on the surface of fuel cladding rods during the operation of Pressurized Water Reactors (PWR). CRUD has deleterious effects on reactor operation and currently, there is no effective way to mitigate its formation. The Electric Power Research Institute (EPRI) CRUD Resistant Fuel Cladding project has the objective to study the effect of different surface modifications of Zircaloy cladding on the formation of CRUD, and ultimately minimize its effects. This modification will alter the surface chemistry and therefore the CRUD formation rate. The objective of this study was to construct a pool boiling facility at atmospheric pressure and sub-cooled boiling conditions, and test a series of samples in simulated PWR water with a high concentration of nanoparticulate CRUD precursors. After testing, ZrC was the only material out of six that did not develop dark, circular spots, which are hypothesized to be the beginnings of CRUD boiling chimneys. Further testing will be needed to confirm that it is indeed more CRUD resistant, even under realistic PWR conditions in a parallel testing facility.
by Ekaterina Paramonova.
S.B.
Wezenberg, Sander Johannes. "Exploring metallosalen complexes in materials science and catalysis." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/37357.
Повний текст джерелаMetallosalen complexes [salen = N,N’-bis(salicylidene)ethylenediamine] have been well-studied in homogeneous catalysis and lately reveive inceasing interest in materials science and multimetallic catalysis. In view of this, we have explored the potential of Zn(II)-centered salphen [N,N’-bis(salicylidene)phenylenediamine] complexes as a building block in the development of new materials and multimetallic systems. The first chapters of this thesis provide a better understanding of the properties of these complexes and this is followed by application as a chiral sensor and studies of their self-assembly behavior. The last chapters focus on multimetallic metallosalen systems for application in cooperative catalysis using supramolecular and covalent approaches. This thesis illustrates the potential of metallosalen complexes for application in materials science and cooperative catalysis
Nordborg, Anna. "Synthesis and modifications of materials for separation science." Doctoral thesis, Umeå : Department of Chemistry, Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1572.
Повний текст джерелаZhu, Bocheng. "Surface initiated polymerisation for applications in materials science." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10858.
Повний текст джерелаBoyaval, Sébastien. "Mathematical modelling and numerical simulation in materials science." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00499254.
Повний текст джерелаAccanoor, Kalyani. "An Overview of the Subject Gateway: Materials Science." Information and Library Network Centre, An IUC of University Grants Commission, Ahmedabad - 380 009, Gujarat (INDIA), 2003. http://hdl.handle.net/10150/105918.
Повний текст джерелаHopkins, Noel Paul. "Abradable coatings : from black art, to materials science." Thesis, Swansea University, 2007. https://cronfa.swan.ac.uk/Record/cronfa42844.
Повний текст джерелаBowerbank, Pat. "The strategic development of a health care organisation : a longitudinal study of the South African physiotherapy profession, 1971 to 2000." Doctoral thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/22077.
Повний текст джерелаThis research focuses specifically on the South African physiotherapy profession, that societal institution which is primarily concerned with health, illness and the physical elements of movement In the human body. Together with South African society as a whole this Institution has experienced monumental changes over the last 30 years. The objective of this research is to describe and critically evaluate the nature, direction and depth of those changes for the South African physiotherapy profession. To this end the research attempts to Identify some of the broad political and societal trends in the macroenvironment, and to contextualise these within the healthcare environment and the physiotherapy profession. The main argument is that social circumstances determine not only the health of the population, but also the health care services and how health care professionals function In society (Benatar, 1997). Health care services and how health care professional's function in society are socially constructed phenomena and therefore there are marked differences in the way health care is delivered from country to country and one political system to another. Over the past decade, management research has increasingly paid attention to the manner in which organisations work to Influence and shape their environments (Lawrence, 1999). A central Issue has become the manner in which organisational environments are constituted, reproduced and transformed through organisational action and relationships.
Ivey, Dorothy Lyle. "Attitudes towards the library and information profession among practising librarians and information workers in the Western Cape." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/15825.
Повний текст джерелаAn investigation was undertaken into the attitudes held by library/information workers towards their profession because it was considered that the strength of these attitudes may affect not only the self-concept and work performance of individuals, but also the quality and dimensions of the support received by the profession from society. The study was conducted in two parts: the literature survey and the empirical investigation. The empirical investigation was limited geographically to the Western Cape region of South Africa.
Jain, Anubhav Ph D. Massachusetts Institute of Technology. "The Materials genome : rapid materials screening for renewable energy using high-throughput density functional theory." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69789.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 204-211).
This thesis relates to the emerging field of high-throughput density functional theory (DFT) computation for materials design and optimization. Although highthroughput DFT is a promising new method for materials discovery, its practical implementation can be difficult. This thesis describes in detail a software infrastructure used to perform over 80,000 DFT computations. Accurately calculating total energies of diverse chemistries is an ongoing effort in the electronic structure community. We describe a method of mixing total energy calculations from different energy functionals (e.g., GGA and GGA+U) so that highthroughput calculations can be more accurately applied over a wide chemical space. Having described methods to perform accurate and rapid DFT calculations, we move next to applications. A first application relates to finding sorbents for Hg gas removal for Integrated Gas Combined Cycle (IGCC) power plants. We demonstrate that rapid computations of amalgamation and oxidation energies can identify the most promising metal sorbents from a candidate list. In the future, more extensive candidate lists might be tested. A second application relates to the design and understanding of Li ion battery cathodes. We compute some properties of about 15,000 virtual cathode materials to identify a new cathode chemistry, Li₉V₃(P₂O₇)₃(PO₄)₂ . This mixed diphosphate-phosphate material was recently synthesized by both our research group and by an outside group. We perform an in-depth computational study of Li₉V₃(P₂O₇)₃(PO₄)₂ and suggest Mo doping as an avenue for its improvement. A major concern for Li ion battery cathodes is safety with respect to 02 release. By examining our large data set of computations on cathode materials, we show that i) safety roughly decreases with increasing voltage and ii) for a given redox couple, polyanion groups reduce safety. These results suggest important limitations for researchers designing high-voltage cathodes. Finally, this thesis describes the beginnings of a highly collaborative 'Materials Genome' web resource to share our calculated results with the general materials community. Through the Materials Genome, we expect that the work presented in this thesis will not only contribute to the applications discussed herein, but help make high-throughput computations accessible to the broader materials community.
by Anubhav Jain.
Ph.D.
Tsai, Tsung-hsun 1961. "Hydrodynamical instability of the mushy layer during directional solidification of ammonium chloride solution in a Hele-Shaw cell." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282278.
Повний текст джерелаHall, Abraham. "Using Freebase, an Automatically Generated Dictionary, and a Classifier to Identify a Person's Profession in Tweets." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5788.
Повний текст джерелаM.S.
Masters
Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science