Дисертації з теми "Ceramic studies"
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1
Long-Hwu, Keh. "Fracture studies of metal/ceramic laminates." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390495.
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2
Basaran, Yanki. "Studies On The Development Of Magnetoelectric Ceramic Composites." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609612/index.pdf.
Повний текст джерелаАнотація:
The aim of this thesis work was to develop magnetoelectric (ME) composites consisting of piezoelectric and magnetostrictive components. The piezoelectric constituent was selected as a PZT ceramic modified by strontium, bismuth and manganese. The magnetostrictive phase was nickel ferrite (NF) ceramic doped by cobalt, copper and manganese. The properties of component phases were optimized in order to enhance the ME effect in the composite.
In the first part of the thesis, effects of sintering temperature on the dielectric and piezoelectric properties of PZT and on the electrical and magnetic properties of NF ceramics were investigated in the temperature range covered from 1150 to 1250 °C. The best piezoelectric properties in PZT were attained at 1250 °
C. At this sintering temperature, values of piezoelectric strain coefficient, dielectric constant, and electromechanical coupling coefficient were 434 pC/N, 1320 and 0.48, respectively. NF ceramics showed poor densification
80 %TD was attained at 1250 °
C. In order to obtain higher densities in ferrites, Bi2O3 was used as a sintering aid. Addition of Bi2O3 enhanced densification up to 97 %TD, and improved electrical and magnetic properties of ferrites. Highest DC-resistivity of 1.15*10^8 ohm-cm and highest magnetostriction of ~26 ppm were attained in NF ceramics doped with 1 wt% Bi2O3. In the second part of the thesis, ME composites were manufactured either as bulk composites or as laminated composites. The efficiency of different composite types was evaluated in terms of voltage output in response to the applied magnetic field. Higher outputs were observed in laminated composites.
3
Akhtar, Mohammad Javed. "Experimental and theoretical studies of electronic ceramic oxides." Thesis, Keele University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292723.
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4
Gong, Yuze. "Wear Studies on Silicon Carbide Whisker Reinforced Alumina." Thesis, KTH, Materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35923.
Повний текст джерелаАнотація:
Wear and biological response to wear debrisof artificial joints remain the major concerns in total hip arthroplasty (THA) [1].Silicon carbide reinforced alumina, Al2O3-SiCw,can be considered as a candidate for hip implants due to its high hardnessand toughness, aswell as chemical inertness. In this study, thewear and friction properties of Al2O3-SiCw areinvestigated by pin-on-disc experiments, with Hank’s Buffered Salt Solution(HBSS) as lubricant. Comparisons with BIOLOX®delta,the most commonly used ceramic in THA, under the same test conditions are made as well.
5
Daley, Chrysanna R. "The Ceramic Body: Concepts of Violence, Nature, and Gender." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/scripps_theses/784.
Повний текст джерелаАнотація:
This thesis is an exploration of the connection between women and nature, specifically the violence that has been inflicted upon them both and how it is interrelated. I positioned my research within the field of Ecofeminism, which critiques the language we (as a Western culture) use to associate women with nature and vice-versa. Traditionally, women are more often associated with nature than men are, and the environment is personified as “Mother Nature”. I argue that uncritically gendering nature as “female” is problematic because of the associations we typically make between the two, and the expectations and values we assign to them based on this association. Nature is historically viewed as inferior to civilization, and women as inferior to men: they are supposedly giving, nurturing, and passive, as opposed to taking, empowered, and active. While the assumption that women are inherently more "connected" to nature is harmful and perpetuates these stereotypes, there is truth in that women, and in fact all oppressed groups (based on race, sexuality, class, ability, etc), share with nature the common history of subordination and inflicted violence by the hegemony.
6
Lyons, Jed S. "Micromechanical studies of crack growth in ceramic matrix composite." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/16086.
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7
Constable, Christopher Paul. "Raman microscopic studies of PVD deposited hard ceramic coatings." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19498/.
Повний текст джерелаАнотація:
PVD hard ceramic coatings grown via the combined cathodic arc/unbalance magnetron deposition process were studied using Raman microscopy. Characteristic spectra from binary, multicomponent, multilayered and superlattice coatings were acquired to gain knowledge of the solid-state physics associated with Raman scattering from polycrystalline PVD coatings and to compile a comprehensive spectral database. Defect-induced first order scattering mechanisms were observed which gave rise to two pronounced groups of bands related to the acoustical (150-300cm[-1]) and optical (400-750cm[-1]) parts of the phonon spectrum. Evidence was gathered to support the theory that the optic modes were mainly due to the vibrations of the lighter elements and the acoustic modes due to the vibrations of the heavier elements within the lattice. A study into the deformation and disordering on the Raman spectral bands of PVD coatings was performed. TiAIN and TiZrN coatings were intentionally damaged via scratching methods. These scratches were then analysed by Raman mapping, both across and along, and a detailed spectral interpretation performed. Band broadening occurred which was related to "phonon relaxation mechanisms" as a direct result of the breaking up of coating grains resulting in a larger proportion of grain boundaries per-unit-volume. A direct correlation of the amount of damage with band width was observed. Band shifts were also found to occur which were due to the stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of "droplets", a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets. Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved successful. This was then expanded to real wear situations in which tools were monitored after 3,6,12,64,120 and 130 minutes-in-cut. A PCA chemometrics model able to distinguish between component layers and oxides was developed. Raman microscopy was found to provide structural and compositional information on oxide scales formed on the surfaces of heat-treated coatings. Wear debris, generated as a consequence of sliding wear tests on various coatings, was also found to be primarily oxide products. The comparison of the oxide types within the debris to those formed on the surface of the same coating statically oxidised, facilitated a contact temperature during sliding to be estimated. Raman microscopy, owing to the piezo-spectroscopic effect, is sensitive to stress levels. The application of Raman microscopy for the determination of residual compressive stresses within PVD coatings was evaluated. TiAlN/VN superlattice coatings with engineered stresses ranging -3 to -11.3 GPa were deposited onto SS and HSS substrates. Subsequent Raman measurements found a correlation coefficient of 0.996 between Raman band position and stress (determined via XRD methods). In addition, there was also a similar correlation coefficient observed between hardness and Raman shift (cm-1). The application of mechanical stresses on a TiAlCrN coating via a stress rig was investigated and tensile and compressive shifts were observed.
8
Hampton, J. Holly D. "Experimental and theoretical studies of the filtration of ceramic suspensions." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70346.
Повний текст джерелаАнотація:
The filtration mechanics of the slip casting and filter pressing ceramic forming processes are analyzed so that better control can be achieved over these processes. The rheological behaviour of alumina suspensions with different solids loadings, particle size distributions and amounts of deflocculant as well as the effects that these suspensions have on the filtration process were studied.During slip casting the formation of the filter cake occurs as a result of the capillary suction pressure of the pores in the plaster of Paris molds. Therefore, the mold microstructure, density, permeability, suction pressure and the effects that these mold properties have on the filtration process are analyzed as a function of the plaster/water ratio used to form the molds.
During filtration, as the cake thickness increases with casting time, fine particles can be carried along with the filtrate and deposited within the filter cake and/or filter medium thereby clogging and reducing the permeabilities of the porous media. This in turn affects the growth rate as well as the permeability, density and porosity of the cake. Evidence of cake and filter medium clogging was obtained by: (1) SEM analysis of cakes and filter media, (2) surface area measurements of cross-sections of cakes, and (3) measurements of cake thickness as a function of casting time.
A computer model consisting of a network of tubes with a random size distribution has been developed to simulate the filtration process. The model accounts for porous media clogging due to: (1) fine particles depositing on the pore walls and gradually reducing the pore radii and (2) pores trapping particles larger than the pore openings. The network model shows that the permeability of the porous medium is dependent upon its pore size distribution rather than its average pore size. The model also illustrates that minor changes in the pore size distribution due to clogging can significantly affect its permeability and casting rate.
9
Kirkup, Leslie. "Experimental studies on bulk and thick film high Tâ†c superconductors." Thesis, University of the West of Scotland, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236309.
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10
Miyazaki, Kazunari. "Studies on proton-conducting ceramic fuel cells for hydrogen-carrier utilization." Kyoto University, 2020. http://hdl.handle.net/2433/254526.
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11
Sagane, Fumihiro. "Studies on ion transfer at interface between ceramic and liquid electrolytes." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136302.
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12
Tanardi, Cheryl Raditya. "Organically-modified ceramic membranes for solvent nanofiltration : fabrication and transport studies." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS259/document.
Повний текст джерелаАнотація:
La nanofiltration (NF) est un procédé applicable à la récupération des solvants organiques. Une membrane chimiquement stable est alors requise pour résister aux solvants organiques. Cette thèse traite de la préparation de membranes NF chimiquement stables par greffage de substrats céramiques mésoporeux et de l'étude de leurs propriétés de transport des solvants et des solutés. Dans le chapitre 1, l'état de l'art sur les techniques de greffage est présenté ainsi que celui sur le comportement au transport des membranes NF résistantes aux solvants.Dans les chapitres 2 et 6, des membranes d'ultrafiltration en alumine mésoporeuse sont greffées avec des groupements organiques hydrophobes ou hydrophiles. La diminution du diamètre des pores permet ainsi d'accéder à la nanofiltration. Au chapitre 5, un agent couplant est utilisé pour améliorer l'ancrage de ces groupements dans les pores. Ceci réduit cependant la perméabilité aux solvants, en comparaison aux mêmes membranes modifiées avec du polydiméthylsilane (PDMS) mais sans agent couplant. Dans le chapitre 6, la capacité de greffage de poudres d'alumine est mesurée pour des agents de greffage différant par : la masse moléculaire des chaines polyéthylènes glycol (PEG), la nature et le nombre de groupements alcoxy terminaux et la présence ou non de fonctions urée. Ces poudres sont analysés par thermogravimétrie, spectrométrie RMN du 29Si, spectroscopie FTIR, et mesures de surface spécifique. Les densités de greffage estimées varient avec la masse des greffons, la présence de fonctions urée, et le nombre de groupements alcoxy hydrolysables.Le comportement au transport de membranes greffées est étudié dans les chapitres 3, 4 et 6. Dans le chapitre 3, pour des membranes greffées avec du PDMS, ce comportement est décrit en incorporant des termes relatifs à la sorption des solvants dans l'équation Hagen-Poiseuille. Une membrane plus fermée est obtenue lorsque le solvant est fortement adsorbé dans la couche greffée. Dans le chapitre 4, la validité des modèles de rejet de soluté basés sur l'exclusion par la taille est discutée. Une forte influence du diamètre moléculaire du soluté et du rapport de ce diamètre avec celui des pores est observée, indiquant que le mécanisme d'exclusion par la taille est ici vérifié. Trois modèles de rejet sur la base d'exclusion par la taille, à savoir Ferry, Verniory et SHP, sont testés pour prédire, en l'absence de solvant, le rejet des solutés à partir des diamètres de pore mesurés par physisorption de diazote. Pour des colorants et des solutés de type PS ou PEG dans du toluène, les données expérimentales sont bien au-dessus des valeurs prédites par ces modèles. Les résultats suggèrent que le diamètre de pore effectif en présence de solvant fortement adsorbé tel que le toluène est inférieur à celui en l'absence de solvant, une hypothèse étant qu'il n'y a pas d'interactions importantes entre solvant et soluté ou entre le soluté et la surface des pores. Cela peut expliquer un rejet plus élevé des solutés dans des solvants non polaires comme le toluène que dans des solvants polaires tels que l'isopropanol pour les membranes greffées avec du PDMS. Dans le chapitre 6, la perméabilité de membranes greffées avec des PEG est étudiée pour différents solvants (polaires ou non polaires). Une relation linéaire entre le flux et la pression transmembranaire est observée, comme pour les membranes greffées avec du PDMS. Cela indique l'absence de processus induit par des effets de cisaillement dans le fluide en écoulement et variant avec la pression transmembranaire appliquée. Pour le colorant Noir Soudan, une sélectivité supérieure est observée dans l'éthanol que dans l'hexane alors que pour la perméabilité inférieure de l'éthanol est inférieure à celle de l'hexane. Ici aussi, ces phénomènes sont expliqués par la différence de sorption des solvants dans la couche greffée. Les conclusions générales et perspectives de cette étude sont présentées dans le chapitre 7Solvent nanofiltration is a potential technology to recover solvents. For this application, a chemically stable membrane that can endure continuous exposure towards organic solvents is required. This thesis deals with the preparation of chemically stable NF membranes through modification of mesoporous ceramic substrate by means of grafting and studying of their solvent and solute transport properties. In Chapter 1, the background of the grafting technique as well as studies on the SRNF transport behavior found in the literature was presented.In Chapter 2 and 6 of this thesis, mesoporous y-alumina UF membranes were grafted by hydrophobic and hydrophilic organic moieties to decrease the membrane pore diameter of the existing y-alumina UF membrane down to the nanofiltration range. In Chapter 5, the use of coupling agent to couple the grafted moiety forming a polymer network inside the ceramic pores during grafting results in a smaller membrane pore, but at the cost of a lower solvent permeability, when compared with PDMS-grafted alumina membranes where no coupling was applied. In Chapter 6, the grafting performance of γ-Al2O3 powder with various PEG grafting agents having different molecular weights, alkoxy groups, and ureido functionalities were analysed by TGA, 29Si-NMR, FTIR, and BET. The grafting densities are influenced by the molecular weights, the presence of the ureido functionality, and the number of hydrolyzable groups of the grafting agents. The transport behavior of PDMS grafted ceramic membranes and PEG grafted ceramic membranes were studied in Chapter 3, 4, and 6. In Chapter 3, the solvent transport behavior of PDMS grafted ceramic membranes was described by incorporating solvent sorption terms in the Hagen-Pouiseuille equation. A more closed membrane structure is realized when the solvent is strongly sorbed in the grafted moiety. In Chapter 4, the applicability of the existing solute rejection models based on size-exclusion mechanism to describe the solute rejection of membranes towards different types of solvent and solute were assessed. A strong function of rejection behavior with the ratio of the solute diameter versus the membrane pore diameter was observed, indicating that the size-exclusion mechanism may be applicable. Three rejection models based on size-exclusion, namely the Ferry, Verniory, and SHP models were used to predict the rejection of several solutes using pore diameter information from the N2 physisorption measurement when no solvent is present. For dye, PS, and PEG solutes in toluene, the experimental data fall well above the predicted σ for Ferry, Verniory, and SHP model suggesting that the membrane actual pore diameter in the presence of strongly sorbed solvent like toluene is smaller than that when no solvent is present, assuming that there is no important solvent-solute or solute-membrane interaction present in the observed rejection behavior. This may explain the higher rejection of solutes in nonpolar solvents like toluene than that in polar solvents such as isopropanol for PDMS grafted ceramic membranes. In Chapter 6, the permeability behavior of PEG grafted y-alumina membranes with respect to different types of permeating solvent (polar and nonpolar) was studied. A linear relationship between flux and TMP was observed, as was also found for PDMS grafted y-Al2O3 membranes. This indicates the absence of shear-flow induced behaviour in the applied TMP. A higher selectivity of Sudan Black in ethanol than in hexane accompanied by a lower permeability of ethanol than hexane were observed. Here also this phenomenon is explained by the difference in solvent sorption of the grafted moiety for different types of permeating solvents. Finally, the general conclusions and future work are presented in Chapter 7
13
Zhu, Na. "Studies on the synthesis, stability and properties of a new ferroelectric ceramic." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505340.
Повний текст джерелаАнотація:
Recently there has been great interest in a new ferroelectric phase, BaThOs (BT2), due to its high permittivity. The crystal structure and thermal stability of BT2 have been previously characterised but difficulties arose due to the challenging synthesis conditions, particularly that phase-pure BT2 can not be synthesised using a simple, conventional solid-state reaction method. Wet chemical synthesis of this phase has been successful in some cases although accurate and effective experimental methods remain unclear. BT2 can be obtained by quenching the eutectic composition from above 1320 °C and has also been prepared as single crystals grown from melts. This indicates that BT2 may, in fact, be a thermodynamically stable phase over a narrow range of temperatures close to melting, We have therefore started to reinvestigate the BaO-Ti02 phase diagram to determine whether BT2 is thermodynamically stable at high temperatures only and modify the phase diagram. Subsequently, we have researched the electrical properties and the iD-f1uence of dopants on the synthesis process and the electrical properties. The stability range ofBT2 has been identified thus: BT2 is kinetically stable but thermodynamically metastable below 1150 °C; however, BT2 is thermodynamically stable over a narrow range of temperatures between 1220 and 1230 °C; BT2 does not appear at temperatures close to the melting point (- 1325 °C), which agrees with recent phase diagrams; the formation and decomposition kinetics are very temperature dependent, especially at temperatures close to the stability range, 1220 to 1230 °C. Based on the stability of BT2, the BaO-TiOz phase diagram was modified and BT2 was synthesised both below 1150 °C, and between 1220 °C and 1230 °C using solid state reaction for the first time. BT2 ceramic sintered at 1220 °C for 207 hours shows excellent properties: e'max is 190; Tc is 426°C. The e'max value is two orders of magnitude lower than for single crystals along the b-axis, but is higher than for BT2 ceramic synthesised by -sol-gel method with lower sintering temperature. T c is composition-dependent. Tano remains low from room temperature to 400 DC ® 0.09), and are lower than the values for single crystal BT2. A higher sintering temperature (but one which avoids BT2 decomposition) produces a BT2 ceramic with higher a', lower Ea. Iso- and alio-valent dopants on A- and B-sites have an effect on the stability, structure and the electrical properties ofBT2 to different degrees. Ge and Al reduce, but Zr increases, the stable temperature range ofBT2, Ca does not influence it. There is an approximately linear relationship between ionic radius difference and cell volume difference for Ge4+, Sn4+ and Zr4+. a'max values for doped BT2 ceramics range from 30 to 57. All samples are highly insulating. Ge increases Tc ofBT2; Al, Sn, Zr and Nb reduce Te by different amounts; Ca does not change Te. Tano data are low ® 0.007) from room temperature to 400 DC. La- and Nb-doped BT2 obtain a mixture phases with more BT than BT2; they have almost temperature-independent permittivity (-30). BT2 can not be synthesized from BaC03 with Ba6Th7040 (B6T17) and Ba4Ti13030 ( (B4T13) in a solid state reaction. The permittivity for B6T17 and B4T13 are - 46 and - 37, respectively. Tano values for B6T17 and B4T13 are below 0.01 between room temperature and 500 DC.
14
Leach, Matthew J. "Synthesis and multinuclear magnetic resonance studies of some nitrogen-containing ceramic phases." Thesis, Durham University, 1990. http://etheses.dur.ac.uk/6291/.
Повний текст джерелаАнотація:
This Thesis describes the synthesis of a range of sialon ceramic phases, and their characterisation using multinuclear magnetic resonance and powder X-ray diffraction.Sihcon-29 and aluminium-27 MAS NMR spectroscopies have been used in the past on a range of inorganic systems, with considerable success. In this study, they were applied to phases in M-Si-Al-O-N systems, with M=La, Y, Li, Mg and Ca, leading to an improved understanding of the factors affecting chemical shifts and other NMR parameters. It was found that some structural information on, for example, 0/N ordering was not available from (^29)Si and (^27)Al NMR, but could be obtained from studies of other nuclei. Nitrogen-15 and oxygen-17 were selected for further study. The low natural abundances of these nuclei meant that isotopically enriched materials had to be prepared. The synthesis of a-Si(^15)(_3)N(_4), Mg(^17)O and Si(^17)O(_2), and of enriched sialon materials is described, and also (^15)N and (^17)0 MAS NMR studies of many sialon phases. In particular, the (^15)N and (^29)Si spectra of lanthanum new phase, a phase of previously unknown structure, were combined with a Patterson map from powder XRD data to allow the crystal structure of this phase to be determined. Finally, the feasibility of using other nuclei to study ceramic structures has been investigated, and (^9)Be, (^7)Li and (^139)La NMR spectra of several phases are reported.
15
Junior, Gilberto Rocha Santiago. "Studies on the use of aluminum processing residues as raw material ceramic." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2224.
Повний текст джерелаАнотація:
FundaÃÃo de Amparo à Pesquisa do Estado do CearÃOs resÃduos da produÃÃo de aluminio a partir da bauxita, chamados de borra, contÃm uma quantidade razoÃvel daquele metal, justificando seu reaproveitamento. ApÃs a retirada do aluminio em fornos rotatÃrios com sal fundido, resta uma âborra pretaâ, rica em sais solÃveis (50 a 70%), e contendo uma boa quantidade de aluminio (cerca de 5%). Esse material à danoso ao ambiente, exigindo tratamentos e aterros especÃficos. à possÃvel utilizÃ-lo como matÃria-prima para as indÃstrias de cimento e de refratÃrios, devido, principalmente, à elevada quantidade de alumina presente. Este trabalho apresenta resultados preliminares para a utilizaÃÃo da borra preta, apÃs retirada do sal por lavagem, como matÃria-prima cerÃmica. Foram prensadas amostras (26 MPa) e sinterizadas a 1000, 1200 e 1500ÂC. O material foi caracterizado por DifraÃÃo de Raios X, FluorescÃncia de Raios X, AnÃlise TermogravimÃtrica e BET. Foram realizados ensaios de absorÃÃo de Ãgua, retraÃÃo linear, resistÃncia a flexÃo e micro-dureza, para avaliar as propriedades das peÃas obtidas.
Aluminum dross from the processing of bauxite ores still contain a reasonable amount of metallic Al. Therefore, it is attractive for many companies to recover the remaining Al from the dross in rotary furnaces usin g molten salts. The residue from this operation, called salt cake, is rich in solubl e salts (50 a 70%), and still contains about 5% Al. This material is harmful to the enviro nment and must be properly treated and disposed. It is possible to use it as a raw material for the cement and refractory industries, due to the high amounts of a lumina present. This work presents preliminary results on the use of a black dross (after salt removal by washing ) for the manufacturing of refractory ceram ics. Test pieces were pressed at 26 MPa and fired at 1000, 1200 e 1500ÂC. The mat erial was characterized by X! ray diffraction and X!ray fluorescency. Water absor ption, linear retraction and microhardness tests were also performed in order to assess the properties of the samples
16
Herrmann, Corey A. "Ceramic analysis of the Tabuchila Complex of the Jama River Valley, Manabi, Ecuador." Thesis, Colorado State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10241321.
Повний текст джерелаАнотація:
Archaeological excavations by the Proyecto Arqueológico-Paleoetnobotánico Río Jama (PAPRJ) in the Jama River Valley of northern Manabí, Ecuador, have established a cultural chronology spanning over three millennia of prehispanic occupation. One of these occupations, the Tabuchila Complex of the Late Formative Period (1000 – 500 BCE), remains poorly understood. Excavations at three sites in the Jama Valley in the 1990s recovered ceramic, lithic, obsidian, paleobotanical, archaeofaunal, and human skeletal remains from Late Formative Tabuchila contexts, with the goal of orienting Late Formative occupation of the northern Manabí region to its contemporaries in western lowland Ecuador.
This study employs modal ceramic analysis to recognize and catalogue formal and stylistic variation within the recovered Tabuchila ceramic assemblage. Through this analysis the Tabuchila assemblage is compared to other studies of Late Formative Chorrera assemblages to understand how Tabuchila represented a regional variant of and contributor to the formation of the Chorrera ceramic tradition. In addition, a sovereignty-based theoretical approach explores how this ceramic assemblage reflects deeper processes of emergent social complexity and early attempts at establishing inequality in northern Manabí’s regional mound center of San Isidro. Results and discussions of the analysis examine a community connected with its Middle and Late Formative contemporaries across the western lowlands and engaged in feasting activity in the vicinity of the central mound of San Isidro.
17
Halverson, Howard Gerhard. "Durability of Ceramic Matrix Composites at Elevated Temperatures: Experimental Studies and Predictive Modeling." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27834.
Повний текст джерелаАнотація:
In this work, the deformation and strength of an oxide/oxide ceramic matrix composite system under stress-rupture conditions were studied both experimentally and analytically. A rupture model for unidirectional composites which incorporates fiber strength statistics, fiber degradation, and matrix damage was derived. The model is based on a micromechanical analysis of the stress state in a fiber near a matrix crack and includes the effects of fiber pullout and global load sharing from broken to unbroken fibers. The parameters required to produce the deformation and lifetime predictions can all be obtained independently of stress-rupture testing through quasi-static tension tests and tests on the individual composite constituents. Thus the model is truly predictive in nature. The predictions from the model were compared to the results of an extensive experimental program. The model captures the trends in steady-state creep and tertiary creep but the lifetime predictions are extremely conservative. The model was further extended to the behavior of cross-ply or woven materials through the use of numeric representations of the fiber stresses as the fibers bridge matrix cracks. Comparison to experiments on woven materials demonstrated the relationship between the behavior of the unidirectional and cross-ply geometries. Finally, an empirical method for predicting the durability of materials which exhibit multiple damage modes is examined and compared to results of accurate Monte Carlo simulations. Such an empirical method is necessary for the durability analysis of large structural members with varying stress and temperature fields over individual components. These analyses typically require the use of finite element methods, but the extensive computations required in micromechanical models render them impractical. The simple method examined in this work, however, is shown to have applicability only over a narrow range of material properties.Ph. D.
18
Kleiman, Shanti Lisa. "Ceramic filter manufacturing in Northern Ghana : water storage and quality control." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67230.
Повний текст джерелаАнотація:
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.Page 6 missing. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 68-70).
In 2009, Pure Home Water (PHW), a Ghana based non-profit organization working to provide affordable and safe drinking water to people in the Northern Region of Ghana, began the construction of a ceramic pot filter (CPF) factory near the city of Tamale. By 2011, the factory had the molds, supplies, and kiln necessary for large-scale filter production, but needed to both increase its own water storage capacity, and to implement quality control standards. This thesis documents elements of PHW's efforts to bring household water treatment and safe storage (HWTS) to scale through local manufacturing of ceramic pot filters. Specifically, it records work done between January and April 2011 to build water infrastructure for the PHW factory and to improve quality control for CPF production. Detailed documentation of the design and construction of an underground water storage system, observations about the iterative process of establishing standardized quality control procedures, and recommendations for additional research, are provided to serve as a practical guide for PHW management and others who may engage in similar work in the future.
by Shanti Lisa Kleiman.
M.Eng.
M.C.P.
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Behebehani, Haider S. J. "Synthesis and thermal studies of boron-containing heterosiloxanes, and their relevance to ceramic formation." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760659.
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Banini, Godsway Kwaku. "Studies of Vickers indentations in ceramic and semiconductor crystals using cathodoluminescence and photoluminescence techniques." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620669.
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Näpänkangas, R. (Ritva). "Fixed metal ceramic prostheses:treatment need, complications and survival of conventional fixed prosthodontics." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514265408.
Повний текст джерелаАнотація:
Abstract
The aims of this study were to evaluate the treatment need of fixed
bridges according to the distribution of pontics in dentition in different
age groups, and to investigate the primary and late complications and
survival of the conventional fixed metal ceramic prostheses, as well as
patients' satisfaction with the prosthetic treatment.
The whole material consisted of the patients treated with fixed metal
ceramic prostheses by undergraduate students at the Institute of Dentistry
during the years 1984 - 1996. There were altogether 772 patients, 460
women (60 %) and 312 men (40 %). Their mean age was 47 years (23 - 81
years). Altogether 944 single metal ceramic crowns and 543 fixed bridges
(1374 abutments and 807 pontics) were prepared.
It can be concluded that the fixed bridges are most often prepared to
replace upper first premolars and lower first molars also in the future.
The most usual primary complications related to fixed bridges occurred
during preprosthetic endodontic treatment of abutment teeth and during the
preparation of the root canals. Previous restoration of the prepared tooth
does not have any marked effect on the prognosis of single crowns with
dowels, although anatomically complicated upper lateral incisors and upper
first premolars need special attention in the treatment planning. Patients
were satisfied with aesthetics and function of the fixed metal ceramic
prostheses. Late complications found in clinical examinations were few,
and the survival rate for the fixed metal ceramic bridge prostheses was
calculated to be 84 % after 10 years, long fixed bridges having a lower
survival than the shorter ones.
The treatment need for conventional fixed bridges seems to be highest
among patients over 50 years of age in the future. Age does not influence
the longevity of the fixed prostheses, but basic circumstances of the
mouth, especially low secretion of saliva affected by diseases and/or
medications and high scores of lactobacilli and streptococcus mutans of
the saliva seem to decrease the survival.
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Agrelius, Felicia. "Materializing Trauma: Ceramic Embodiment, Environmental Violence, and the Colonial Legacies Of Mount Baldy." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/scripps_theses/1017.
Повний текст джерелаАнотація:
In this project I argue that trauma is a major component of society. Rather than positioning trauma as an event, I contend that it should be understood as an environmental force. To form this reorientation I look to an actual environment and the ways in which it remembers and responds to systemic violence. Specifically, I track the colonization and exploitation of Mount Baldy, and how natural occurrences such as floods and fires have consistently threatened human development on the mountain. If trauma is both monumentally impactful and an environmental force, then it merits a major rethinking of many of the aspects of human existence that are assumed to be stable. In chapter 1, I move trauma outside of the psychological definitions of the DSM and into a communal and systemic framework. In chapter 2, I use a case study of Mount Baldy to understand how environmental forces react to trauma, which provides a way to imagine how a society or community might collectively operate as a traumatized being. In chapter 3, I undertake a material research process using clay harvested from Mount Baldy. Clay, which mimics characteristics of the human body and is literally a part of the natural environment, connects the embodied nature of trauma for human to the ecological manifestations of trauma. This allows a glimpse at what it might mean to acknowledge trauma as a major component of the human experience.
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Shams, Omar Mohammad Abdulla. "Heat release and performance studies using monolithic ceramic piston caps in a Petter AV1 diesel engine." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293057.
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Vaughan, Sarah J. "A fabric analysis of Late Cypriot Base Ring Ware : studies in ceramic technology, petrology, geochemistry and mineralogy." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281701.
Повний текст джерелаАнотація:
Base Ring Ware is one of the most distinctive and thereby important archaeological hallmarks of the Late Bronze Age in Cyprus. The technical ceramic standards achieved ·inthis ware coupled with its wide. distribution provided a valuable opportunity to study the technological skills of the ancient Cypriot craftsmen as well as to assess the degree of sophistication of their knowledge, and ability to manipulate the local ceramic material resources. By means of standardised macroscopic studies of a large sherd sample of the ware, the range and patterns of production methods were established. These data were then subjected to s ta tis tical clus tering procedures to discover any chronologi'cal, geographical or technical production patterns for the ware. In addition, geochemical analyses were performed on a representative set of sherds to provide a basis for characterising the ware's general geological composition and to determine whether any local variations in the fabric could be identified. For purposes of material comparisons, forty clay samples of various mineralogical types were collected from Cyprus from deposits near the Late Cypriot sites represented by the Base Ring sherds. These clays were also subjected to geochemical analysis and statistical procedures to determine whether any of them could provide useful compositional parallels to the materials of the archaeological samples. The sherds were then examined petrographically and by scanning electron microscopy, microprobe and X-ray diffraction analysis to provide complementary and corroborative data for the geochemical profiles. The Cypriot clay samples were used for manufacturing and firing experiments to compare with Base Ring production techniques, and were subjected to the same analytical procedures as were the sherds. The combined analytical and technical data were then considered for both sherds and clays to determine the degree to which they contributed to a consistent and overall geoiogical characterisation of Base Ring materials and fabrics, and the degree to which they provided important insights into the relative sophistication and regional nature of the Late Cypriot ceramic industry which produced .this remarkable ware
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Kondos, Konstandinos G. "X-ray diffraction and electron microscope studies of yttria stabilzed zirconia (YSZ) ceramic coatings exposed to vanadia." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23814.
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Soriano-Meier, Horacio. "An empirical model to evaluate the adoption of lean production in a craft production environment : the UK ceramic tableware industry." Thesis, Keele University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327652.
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Hacarlioglu, Pelin. "Experimental and Modeling Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29580.
Повний текст джерелаАнотація:
This dissertation describes the preparation of a novel inorganic membrane for hydrogen permeation and its application in a membrane reactor for the study of the methane steam reforming reaction. The investigations include both experimental studies of the membrane permeation mechanism and theoretical modeling of mass transfer through the membrane and simulation of the membrane reactor with 1-D and 2-D models.
A hydrothermally stable and hydrogen selective membrane composed of silica and alumina was successfully prepared on a macroporous alumina support by chemical vapor deposition in an inert atmosphere at high temperature. Before the deposition of the silica-alumina composite, multiple graded layers of alumina were coated on the alumina support with a mean pore size of 100 nm by the sequential application of three boehmite sols with gradually decreasing sol particle sizes of 630, 200 and 40 nm, respectively. The resulting supported composite alumina-silica membrane had high permeability for hydrogen in the order of 10-7 mol m-2 s-1 Pa-1 at 873 K with a H2 /CH4 selectivity of 940 and exhibited much higher stability to water vapor at the high temperature of 873 K. In addition, the same unusual permeance order of Heï¼ H2ï¼ Ne previously observed for the pure silica membrane was also observed for the alumina-silica membrane, indicating that the silica structure did not change much after introduction of the alumina. The permeation of hydrogen and helium through vitreous glass and silica membranes was modeled using ab initio density functional calculations. Comparison of the calculated activation energies to those reported for vitreous glass (20â 40 kJ mol -1) indicated the presence of 5- and 6-membered siloxane rings, consistent with the accepted structure of glass as a disordered form of cristobalite.
The experimental studies of the steam reforming of methane were examined at various temperatures (773-923 K) and pressures (1-20 atm) with a commercial Ni/MgAl2O4 catalyst in a hydrogen selective silica-alumina membrane reactor and compared with a packed bed reactor. One-dimensional and two-dimensional modeling of the membrane rector and the packed bed reactor were performed at the same conditions and their performances were compared with the values obtained in the experimental study. Improved methane conversions and hydrogen yields were obtained in the membrane reactor compared to the packed bed reactor at all temperatures and pressures. From the two modeling studies, it was also found out that the two-dimensional model performed better in the membrane reactor case especially at higher pressures.Ph. D.
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Renzi, Danielle. "Effects of Solids Loadings and Particle Size Distribution on Siphon Ceramic Candle Filters." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3307.
Повний текст джерелаАнотація:
In the rural areas of Madagascar only 29% of the population has access to clean water and 10% has access to improved sanitation. It has been estimated that environmental risk factors, such as inadequate access to clean drinking water and proper sanitation, are responsible for 94% of the diarrheal disease burden. This study was focused on testing a point-of-use technology called the Tulip filter, which is a siphon ceramic candle filter impregnated with silver. The purpose is to assess its feasibility for implementation in rural regions of Madagascar through a laboratory study performed at the University of South Florida.
The study tested the Tulip filters for turbidity, total coliform, and E. coli removal for various types of water. Each filter processed synthetic water classified as control (tap water, <1 >NTU), low turbidity (5-7 NTU), medium turbidity (25-35 NTU), or high turbidity (60-80 NTU). Approximately once every 100 L the filters processed pond water to test coliform removal. Furthermore, the pthesis size distribution was measured to analyze the effectiveness of filter to remove various pthesis sizes. Two of the seven Tulip filters tested had some quality control issues with the glue connecting the ceramic candle to the plastic cap and failed at 350 L.
Of the functioning filters, the turbidity removal ranged from 93% to 98% with none of the 779 samples taken from 4 filters above the WHO recommended 5 NTU for drinking water. The log removal of total coliforms was about 3.90 to 4.16 and achieved an average of 1 CFU/100mL of E. coli in the filtered water. WHO guidelines consider water with 1-10 CFU/100 mL a "low risk" and all but one of the working filters had E. coli and total coliform concentrations within, or below, this range for all samples (n=20 for each filter). The filters also showed an average of 96% removal of pthesiss of all size ranging from 0.5 to 10 µm.
This study finds that the Tulip filter is an appropriate of point-of-use technology that enables rural areas access to "low risk" water, at a low cost and with minimal maintenance. This study also reinforces the importance of adding silver or another biocide to ceramic filters because pthesiss of sizes up to 10 µm are able to pass through the filter. This is particularly a problem because pathogens can range from 0.01 µm to 100 µm.
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Reynoso, Humberto. "Performing Binaries." CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/252.
Повний текст джерелаАнотація:
I take a critical view of sociopolitical and cultural issues dealing with homoeroticism andgay politics. I explore gender theories in order to further understand what it means to bemasculine or feminine and how it affects my placement in society. I use art as a tool forexpressing sexual freedom while questioning traditional sexual identity. I'm interested in exploring ideas of the oppressor and the oppressed, and how power becomes an inevitable force (in every society) that creates a hierarchy, consequently establishing control. But what is power? According to various definitions, power is an entity that possesses and or exercises authority or influence. I want to focus on this idea of exercising authority, which one can argue we need, but why? To prevent chaos or is it to control a society? What about exercising influence? Do we need an influence exercised upon us? Or does that make us subjected to another person's subjective point of views? These are questions that I directly or indirectly ask with my work in relationship to gender, gender roles, and sexual orientation. I am interested in Judith Butler's theory in performing gender, and how in performing gender, one assumes social hierarchy of power depending on what gender we are performing. If I am a man performing as a man then I am treated differently by society than if I am a woman performing as a woman. But what happens if I am a man performing as a man who prefers men as lovers, or a woman who prefers other woman as lovers? In what context is this situation accepted by our society? And is it different for men and women? And why? What does it mean to be a man? What does it mean to be a woman, within the context of performance? Then taking it a step further and argue that we are all performing subjective ideas constructed by social norms.
30
Ozerciyes, Berker. "A Novel Precursor For Synthesis Of Zirconium Tungstate And Preliminary Studies For Nanofiber Production." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610383/index.pdf.
Повний текст джерелаАнотація:
Zirconium tungstate (ZrW2O8) is a ceramic that shows large isotropic negative thermal expansion over a wide range of temperature. This unique property makes it an interesting candidate for applications where thermal expansion mismatch between components constitutes a problem. ZrW2O8 is typically produced by solid-state reaction between zirconium oxide and tungsten oxide at 1200oC. In some studies, ZrW2O8 precursors have been produced from relatively expensive zirconium and tungsten sources. While the origin of negative thermal expansion has been the main focus in the majority of publications, production of particles with controlled size, distribution and morphology has not been studied extensively.
Electrospinning is a simple technique for producing micron/nano sized fibers from polymer solutions. The method can also be used for producing ceramic or polymer/ceramic composite fibers by electrospinning of a mixture of ceramic precursors or ceramic nanoparticles with suitable polymers. Ceramic precursors could be synthesized either by sol-gel or chemical precipitation routes before mixing them with polymer solutions and a final burnout step would be needed, in case the fiber is desired to be composed of the ceramic phase. Electrospinning technique has not been employed to the production of ZrW2O8 ceramic fibers.
In this study a novel precursor for ZrW2O8 from relatively cheaper and abundant starting chemicals, namely zirconium acetate and tungstic acid were used. Experimental details of development of the precursor are presented with a discussion on the effects of solution parameters on the phase purity of the fired product. Besides the solution parameters investigated (i.e. solubility of tungstic acid, adjustment of the stoichiometry, final pH of the solution, ageing time), evolution of the heat treatment protocol was used in the production of phase pure ZrW2O8. Second, the suitability of the developed precursor for producing ZrW2O8 in fiber form was investigated. Preliminary studies involved the adjustment of the viscosity of precursor solution for electrospinning with poly (vinyl alcohol) (PVA). Optimum PVA concentration leading to bead-free nanofiber mats and a method to increase the fiber production rate were reported. The characterization of the products was achieved by SEM and XRD.
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Peabody, Duncan. "Field and Laboratory Comparison of the Hydraulic Performance of Two Ceramic Pot Water Filters." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4199.
Повний текст джерелаАнотація:
Currently 884 million people worldwide are living without access to an improved source of drinking water (WHO/UNICEF, 2011). Piped-water on premises is the ultimate goal of World Health Organization (WHO) due to the ability to treat all of the water and distribute it safely in pressurized pipes. However, Household Water Treatment and Safe Storage (HWTS) is an option for improving the quality of drinking water where that infrastructure is not yet developed, especially where there is a risk of recontamination between point of collection and point of use (Clasen, 2006).
This study analyzed one such HWTS, the ceramic pot water filter. The study compared the hydraulic properties of the FilterPure (FP) and Potters for Peace (PFP) ceramic pot filters through a thirteen-month field study in the Dominican Republic and laboratory studies at the University of South Florida.
In the field study 55 filters were tested for first hour flow rate and hydraulic conductivity. Eight first hour flow rate tests were conducted in the field on one month intervals during months 7- 13. FP filters had an average first hour flow rate of 553 ml/hr and PFP Filters had a first hour flow rate of 395 ml/hr. No significant change in first hour flow rate was observed over time in FP filters. PFP experienced an average increase of 31 ml/hr per month during the seven-month testing period.
Falling head tests were conducted on four filters in the laboratory and the flow rate was modeled to determine hydraulic conductivity. Hydraulic conductivity values for FP filters ranged from k = 0.0495 - 0.0831 cm/hr and for PFP filters ranged from k = 0.0136 - 0.0389 cm/hr.
Eight out of 29 (26%) Potters for Peace filters in the field had first hour flow rates of less than 250 ml/hr by month nine of the study and had to be replaced and removed from the study. In total 24 of 55 (44%) filters (8 FP and 16 PFP) had to be removed from the study due to several reasons discussed in this thesis.
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Cromwell, Robert John. ""Where ornament and function are so agreeably combined" consumer choice studies of English ceramic wares at Hudson's Bay Company, Fort Vancouver /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2006. http://proquest.umi.com/login?COPT=REJTPTU0NWQmSU5UPTAmVkVSPTI=&clientId=3739.
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Elsken, Jennifer L. "The Historical Ceramics of Camp Floyd." BYU ScholarsArchive, 2002. https://scholarsarchive.byu.edu/etd/4665.
Повний текст джерелаАнотація:
This thesis is an historical archaeological project involving the classification and analysis of the ceramics found at Camp Floyd, a 19th century military site 40 miles southwest of Salt Lake City, Utah. United States military troops were dispatched to the Utah Territory to establish a Pony Express Station and an Overland Stage Trail, to assert federal authority in the Territories, and to end the ongoing conflict between the federal government and the Church of Jesus Christ of Latter Day Saints. The primary research question concerned the ceramic usage patterns at Camp Floyd as compared to other military sites and non-residential sites of the 19th century. The ceramic assemblage recovered from Camp Floyd was classified using Berge's classification system of historical ceramics. A sample from this collection was analyzed in order to assess social and economic differences between officers' and enlisted men.
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Patrick, Steven Edward. ""I Would Not Begrudge to Give a Few Pounds More": Elite Consumer Choices in the Chesapeake, 1720-1785 The Calvert House Ceramic Assemblage." W&M ScholarWorks, 1990. https://scholarworks.wm.edu/etd/1539625573.
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Yuellig, Amber J. "Fort Walton ceramics in the Perry Collection, Apalachicola Valley, Northwest Florida." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001997.
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Das, Saikat. "FUNDAMENTAL STUDIES OF SURFACTANT TEMPLATED METAL OXIDE MATERIALS SYNTHESIS AND TRANSFORMATION FOR ADSORPTION AND ENERGY APPLICATIONS." UKnowledge, 2015. http://uknowledge.uky.edu/cme_etds/48.
Повний текст джерелаАнотація:
This work addresses fundamental aspects of designing templates and curing conditions for the synthesis of mesoporous metal oxide thin films. The first section addresses selection of cationic-carbohydrate surfactant mixtures to synthesize templated silica thin films for selective adsorption of simple carbohydrates based on molecular imprinting. Nuclear magnetic resonance and fluorescence spectroscopy results suggest a novel structure for mixtures of alkyl glucopyranosides or xylopyranosides with cationic (trimethylammonium) surfactants. Despite thermodynamically favorable mixing, the carbohydrate headgroups in the mixed micelle adopt an inverted configuration with their headgroups in the micelle core, and therefore are inaccessible for molecular imprinting. This orientation occurs even when the alkyl tail length of the carbohydrate surfactant is greater than that of the cationic surfactant, but this limitation can be overcome by introducing a triazole linker to the carbohydrate surfactant. The next section addresses the effects of aging conditions on the structural and chemical evolution of surfactant templated silica thin films. The third section describes the synthesis of carbohydrate/cationic surfactant imprinted silica thin films with orthogonally oriented cylindrical pores by modifying the glass surface with a random copolymer. The last part of the dissertation addresses the effect of pore orientation on the transformation mechanism of block copolymer templated titania thin films during high temperature curing. Mesoporous titania thin films can be used for photochemical and solar cell applications, but doing so requires addressing the tradeoff between loss of mesostructural order and growth of crystallinity during thermal treatment. By using advanced x-ray scattering techniques it has been shown that the titania films with vertically oriented pores can better withstand the anisotropic stress that develops during thermal treatment compare to titania films with mixed pore orientation. For instance, films with parallel or mixed pores can only be heated at 400 °C for a brief time (~10 min) without loss of order, while orthogonally oriented films can be heated at 550 °C or greater for extended time periods (on the order of hours) without significant loss of long-range mesopore structure. Detailed kinetic modeling was applied to enable the comparison of activation energy for mesostructure loss in films as a function of pore orientation and thickness.
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Shaban, Hannah W. "Arab Americanesque." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5899.
Повний текст джерелаАнотація:
Culture, as defined by Edward Said, is a concept of identity selectively curated through imperialism. Through my ceramic practice, I explore what constitutes my cultural identity as a first generation Arab American. My work, primarily influenced by family narrative was initially expressed through investigations in the figure and viewer relationships with my sculpted figures. As my research progressed into Western Imperialism, I began noticing extensive evidence of colonialism’s lasting effects, especially within Western consumer markets. Interest in the writings of Said, works by French Orientalist painters, family memory, and a general displeasure with the plethora of Middle Eastern design used in Western decor culminates into Arab Americanesque; an installation that explores ideas of cultural obfuscation, power, and belonging.
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Livingstone, Smith Alexandre. "Chaîne opératoire de la poterie: références ethnographiques, analyses et reconstitution." Doctoral thesis, Universite Libre de Bruxelles, 2000. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211722.
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Halvarsson, Mio Elias. "And yet here we are." Thesis, Konstfack, Keramik & Glas, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-7785.
Повний текст джерелаАнотація:
This work is about representation and existing. I’m fat and transmasculine. I’m looking for a reflection in my surroundings, culture, in media and art. I can’t find it, so I have to create it myself. Through materialising bodies in clay that describe what fat transmasculine people can look like I aim to give myself and people who are similar to me something we’re lacking. I claim my existence.
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Herlich, Jessica Marie. "Shellfishing, Ceramics, and Gender: Shell Midden Ceramics from the Kiskiak Site." W&M ScholarWorks, 2011. https://scholarworks.wm.edu/etd/1539626649.
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Slaight-Brown, Shannon M. "Restoration." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4890.
Повний текст джерелаАнотація:
The marks I make in clay have different characteristics, and the physical mark of one’s fingertips or visual record of the hand is personal and intimate. This visible activity is the evidence of my constant presence and control within each object. Its repetitive meditation produces a private relief from my persistent anxieties. This exploration for me is not only visual, but also physical. This is the start of my infatuation with the idea of pattern. It has its own discrete visual language and modes of communication; and through my research I am developing a method of intercommunication.
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Datta, Kaustuv. "Structural studies of novel bismuth containing piezoelectric ceramics." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/3902/.
Повний текст джерелаАнотація:
Perovskite-based materials are in the focus of research not only because of their excellent physical properties, but also because their relatively simple structure facilitates the understanding of structure-property relationships, which is crucial for developing novel materials with improved qualities. Recent research in the field of ferroelectric and piezoelectric materials is concerned with the development of eco-friendly lead-free materials. To achieve this goal, it is important to understand the fundamental correlation between the ‘Structure’ and the ‘Property’. In this work, the primary focus has been to elucidate the structural changes occurring as a function of doping in three different systems: (1) BiScO3-PbTiO3 (BS-PT), a recently developed system which has already attracted much interest because of its superior physical properties near the morphotropic phase boundary (MPB); (2) BiScO3-BaTiO3 (BS-BT), which can be considered as a lead-free analogue of the BS-PT family and lastly, (3) Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT), which is a well-known lead-free material at the NBT-rich side of the phase diagram. Powder samples with a range of compositions for each system were prepared following the solid-state synthesis route and were investigated utilizing both neutron and x-ray powder diffraction and dielectric measurements. Detailed crystallographic information was obtained by Rietveld refinement against the neutron powder diffraction data. Structural phase transitions as a function of temperature were determined by nonambient x-ray powder diffraction and compared with the physical properties of the ceramics using high-temperature dielectric measurements. The significant outcomes are: 1. The best model to represent the so-called MPB of xBS-(1-x)PT system is found to be a mixture of a tetragonal and a monoclinic phases from the powder diffraction data. The structure beyond the MPB compositions is in better agreement for a single monoclinic model with the space group Cm than the accepted space group R3m. By contrast, single crystals with compositions around the MPB provide evidence for a model consisting of two primitive monoclinic cells. 2. The lead-free BS-BT system exhibits an extended phase boundary between tetragonal and pseudocubic phases, which can be modelled by a combination of tetragonal and rhombohedral phases. The incorporation of BS into BT also results in the suppression of the two low-temperature phase transitions of BT. 3. Samples with new compositions synthesized in the xNBT-(1-x)BT system demonstrate a rare enhancement in the tetragonality of the unit cell and an increase in the Curie temperature for compositions where x <= 0.40.
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Hilton, Andrew David. "TEM studies of relaxor ferroelectric materials." Thesis, University of Essex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328755.
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Kemp, Kassie Christine. "Pottery Exchange and Interaction at the Crystal River Site (8CI1), Florida." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5971.
Повний текст джерелаАнотація:
The Crystal River site (8CI1) is a Woodland-period mound (ca. 1000 BC to AD 1050) complex located on the west-central Gulf coast of Florida. Links to the Hopewell Interaction Sphere suggest that the people of Crystal River had connections with a broad range of communities, yet little is known concerning the role the site played in local, regional, or long-distance exchange networks. Pottery traditions vary amongst different communities of practice, therefore the level of interaction at Crystal River can be measured by looking at variation in the ceramic assemblage. I combine type/attribute, vessel form and function, gross paste, and chemical analyses to determine the amount of variability present in the pottery assemblage. These analyses show that Crystal River has a high level of ceramic variation with some spatial and temporal patterning. To determine Crystal River’s membership in and potential role within a sphere of interaction, I compare these patterns to three community types with diverse social interfaces. This research suggests that Crystal River may have started out as a homogenous, residential community but through time began to interact with a number of diverse, regionally associated communities drawn to the site for special occasions.
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Kresa, Jakub. "Studie obrábění keramických materiálů broušením." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231435.
Повний текст джерелаАнотація:
This thesis is focused on ceramics materials in terms of their partition, properties, structure, manufacture and methods of their possible machining. The first part of this thesis is devoted to the distribution of ceramics materials, their structure, properties, and methods of production. Currently, ceramics materials are increasingly used in structural (engineering) applications therefore we deal with methods of effective machining of ceramic materials, to achieve part of the required shape, dimensions and surface quality. The evaluation of ceramic grinding test from the point of view of cutting forces and surface quality of the machined faces are presented in the last part of the thesis. The tested materials have been provided by company SEEIF Ceramics a.s.
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Wade, James Matthew. "Calorimetry studies of high temperature superconductors." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363078.
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Medina, Francelys A. Lanagan Michael Thomas. "Impedance spectroscopy studies of silica-titania glasses and glass-ceramics." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/PSUonlyIndex/ETD-4566/index.html.
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Gurkan, Nurdan. "Studies On Interaction Of Electromagnetic Waves With Barium Hexaferrite Ceramics." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609613/index.pdf.
Повний текст джерелаАнотація:
M-type barium hexaferrite powders doped with titanium and/or cobalt have been synthesized according to the stochiometric formulations BaFe(12 –
(4/3)x)TixO19, BaFe12-xCoxO19 , BaFe12-2xTixCoxO19 (x varying from 0 to 1.5 with an increment of 0.5) by the mixed oxide approach. The powders were used to manufacture small ceramic tiles by sintering each composition at 1250 °
C with soaking times ranging from 1 to 16 hours. XRD work revealed formation of the magnetoplumbite crystal structure in all ceramics. The variations in processing parameters led to differences in microstructure and various dielectric and magnetic properties of the ceramic tiles. The interaction of the ceramics with electromagnetic waves was characterized by using a vector network analyzer in the X and Ku bands. The results revealed that, undoped barium hexaferrite ceramics and those doped with low titanium exhibited good microwave absorption properties.
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Kintaka, Yuji. "Studies on transmittance, refractive index, and dispersion of transparent ceramics." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/174980.
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Akhtaruzzaman, Md. "Dielectric studies of some oxide materials, nitride ceramics and glasses." Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6308/.
Повний текст джерелаАнотація:
This thesis is primarily concerned with the evaluation and comparison of the dielectric behaviour of materials which may find application as substrates in microelectronic high-performance packaging. In the introductory chapter the factors governing the choice of the most suitable dielectric substrate for compatibility with silicon technology are reviewed; it is shown that in addition to good dielectric properties the thermal conductivity is important if high power packages are required together with the ability to obtain good matching of thermal expansion coefficients. This is followed by a survey of the present theories of dielectric behaviour with special emphasis on the Universal law of dielectric response and its applicability to oxide and glass ceramics which exhibit hopping conductivity. The experimental methods for the measurement of dielectric parameters are outlined in Chapter 3 which includes an account of techniques developed for studying materials only available as powders. The three substrate systems studied were aluminium oxide, aluminium nitride and glass-on-molybdenum and in the case of the two former materials a range of both pure and impure specimens were examined both in single crystal and sintered polycrystalline form. The detailed experimental results are presented and discussed in the three succeeding chapters for each of the materials in turn; these results include the values of permittivity and dielectric loss, measured over a frequency range of 5 x 10(^2) Hz to 1 x 10(^7) Hz, the temperature variation of permittivity both in the low temperature (85K to 293k) and high temperature (20ºC to about 600ºC) regions and the d.c. and a.c. conductivity in the high temperature range. In their pure form each of these materials would be suitable as a substrate, having permittivities at room temperature of ϵ ' (_s) = 10.2 for polycrystalline Al(_2)(^0)(_3), ϵ' (_s) = 9.2 for polycrystalline AlN (which has a thermal conductivity of about one-hundred times that of alumina) and ϵ' (_s) - 6.5 for glass-on-molybdenum and dielectric losses in the region of tan δ - 10(^-3). The effect of impurities is shown to be very significant leading in all cases to some increase in permittivity and a much larger increase in dielectric loss. The measurements made on powders are given and discussed in Chapter 7. In the studies on the powders used as starting materials for the manufacture of substrates it was shown that by making measurements at low temperature (77K) the effects of intergranular space charge polarization could be overcome yielding information valuable for quality control of impurity content; measurements made on powders of some high temperature oxide superconducting materials are also given. The final chapter, Chapter 8, summarises the overall conclusions of the research and makes some suggestions for future work.