I am learning through these lessons. The following document includes my convoluted musings about my work, making process, and body leading up to my thesis exhibition, Avoidance Kitchen. My struggle with my reflected image comes from my struggle with my self-perceived physical image. What does it mean for a piece to disappear, only to find the reflection of someone else's work or body in its place? Is my craft rendered obsolete if all you want to do is take a funny selfie? Is my work unacknowledged if all you see is the sculpture across the room, in reverse? What happens when an object or installation is elevated and ignored within the same space?

Fewer women occupy executive-level positions in U.S. companies compared to the number of men. Antidiscrimination laws have been in place for 30 years to combat the threat to gender equality. The purpose of this descriptive phenomenological study was to examine the lived experiences of executive-level women employed in the manufacturing and service-based industries to explore the persistence of the glass ceiling. Social learning theory provided the framework for the study. Data were collected from semi-structured interviews with 12 executive-level women in the Philadelphia metropolitan area. Data analysis involved hand coding and software coding to identify six themes: discrimination, opportunities, support and choices, advantages, balances, and roles. Findings indicated that discrimination against women being promoted to executive positions still exists. Most participants stated that lack of enforcement of antidiscrimination laws and quota programs could be a hindrance to women being promoted to executive-level positions. Findings may be used to support the promotion of women to executive-level positions in the manufacturing and service-based industries in the Philadelphia metropolitan area.

We propose new theoretical models, which generalize the classical Avrami-Nakamura models. These models are suitable to describe the kinetics of nucleation and growth in transient regime, and/or with overlapping of nucleation and growth. Simulations and predictions were performed for lithium disilicate based on data reported in the literature. One re-examined the limitations of the models currently used to interpret DTA or DSC results, and to extract the relevant kinetic parameters. Glasses and glass-ceramics with molar formulation 0.45SiO2? (0.45-x)MgO?xK2O?0.1(3CaO.P2O5) (0?x?0.090) were prepared, crystallized and studied as potential materials for biomedical applications. Substitution of K+ for Mg2+ were used to prevent devritification on cooling, to adjust the kinetics of crystallization and to modify the in vitro behaviour of resulting biomaterials. The crystallization of the glass frits was studied by DTA, XRD and SEM. Exothermic peaks were detected corresponding to bulk crystallization of whitlockite-type phosphate, Ca9MgK(PO4)7, at approximately 900ºC, and surface crystallization of a predominant forsterite phase (Mg2SiO4) at higher temperatures. XRD also revealed the presence of diopside (CaMgSi2O6 in some samples. The predominant microstructure of the phosphate phase is of the plate-type, seemingly crystallizing by a 2-dimensional growth mechanism. Impedance spectroscopy revealed significant changes in electrical behaviour, associated to crystallization of the phosphate phase. This showed that electrical measurements can be used to study the kinetics of crystallization for cases when DTA or DSC experiments reveal limitations, and to extract estimates of relevant parameters from the dependence of crystallization peak temperature, and its width at half height. In vitro studies of glasses and glass-ceramics in acelular SBF media showed bioactivity and the development of apatite layers The morphology, composition and adhesion of the apatite layer could be changed by substitution of Mg2+ by K+. Apatite layers were deposited on the surface of glass-ceramics of the nominal compositions with x=0 and 0.09, in contact with SBF at 37ºC. The adhesion of the apatite layer was quantified by the scratch test technique, having been related with SBF?s immersion time, with composition and structure of the glass phase, and with the morphology of the crystalline phase of the glass-ceramics. The structure of three glasses (x=0, 0.045 and 0.090) were investigated by MAS-NMR ( 29Si and 31P), showing that the fraction of Q3 structural units increases with the contents of Mg, and that the structure of these glasses includes orthophosphate groups (PO43-) preferentially connected to Ca2+ ions. Mg2+ ions show preference towards the silicate network. Substitution of Mg2+ by K+ allowed one to change the bioactivity. FTIR data revealed octacalcium phosphate precipitation (Ca8H2(PO4)6.5H2O) in the glass without K, while the morphology of the layer acquires the shape of partially superimposed hemispheres, spread over the surface. The glasses with K present a layer of acicular hidroxyapatite, whose crystallinity and needles thickness tend to increase along with K content. / São propostos novos modelos teóricos, que generalizam o modelo clássico de Avrami-Nakamura, apropriados para a cinética de nucleação e de crescimento em regime transiente, e/ou com sobreposição entre o estágio de nucleação e o de crescimento. Foram efectuadas simulações com base em resultados da literatura, reportados para o dissilicato de lítio. Foram examinadas as limitações dos métodos correntemente usados para obter estimativas de parâmetros cinéticos, com base em resultados de ATD. Desenvolveram-se e investigaram-se vidros e materiais vitrocerâmicos susceptíveis de aplicação biomédica com a formulação molar 0.45SiO2?(0.45-x)MgO?xK2O?0.1(3CaO.P2O5) (0?x?0.090), preparados mediante a substituição de Mg2+ por K+. A cristalização das fritas de vidro foi estudada por ATD, DRX e SEM. Foram detectados picos exotérmicos correspondentes à cristalização de fosfato (cristalização em volume) do tipo whitlockite Ca9MgK(PO4)7 a aproximadamente 900ºC, e de forsterite (Mg2SiO4) acompanhada de alguma diopside (CaMgSi2O6; cristalização superficial) a temperaturas superiores. A microestrutura predominante da fase fosfato é do tipo placa, aparentando cristalizar por um mecanismo de crescimento bidimensional. Foi usada espectroscopia de impedâncias para monitorizar a cristalização em condições em que os ensaios de ATD ou de DSC revelam limitações, recorrendo a alterações significativas de propriedades eléctricas associadas à cristalização da fase de fosfato. Os vidros e vidros cerâmicos desenvolvidos revelaram bioactividade em meio acelular in vitro, desenvolvendo camadas apatíticas em SBF. A morfologia, composição e aderência da camada de apatite pôde ser modulada com base na substituição parcial de Mg2+ por K+. Foram depositadas camadas de apatite sobre vidros ceramizados (x=0 e 0.09), em SBF a 37ºC. A adesão da camada de apatite foi quantificada pela técnica de indentação deslizante tendo sido relacionada com o tempo de imersão em SBF, com a composição e estrutura da fase vítrea, e com a morfologia da fase cristalina dos vidros cerâmicos. Foi investigada a estrutura de três vidros (x=0, 0.045 e 0.090) por MAS-RMN (29Si e 31P), verificando-se que nos vidros mais ricos em Mg, a participação da unidade estrutural Q3 é mais significativa, e que a estrutura dos vidros inclui grupos ortofosfato (PO43-) mais próximos de iões Ca2+ do que dos iões Mg2+, sendo estes incorporados preferencialmente na rede de silicato. A substituição parcial de Mg2+ por K+ permitiu ajustar a cristalização dos materiais vitrocerâmicos e modular a bioactividade pretendida. Resultados de FTIR revelaram precipitação de fosfato octacálcico (Ca8H2(PO4)6.5H2O) no vidro sem K, enquanto que a morfologia da camada adquire a forma de hemisférios parcialmente sobrepostos, espalhados sobre a superfície. Os vidros com K apresentam uma camada de hidroxiapatite acicular, cuja cristalinidade e espessura de agulhas tende a aumentar com o teor de K.

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This thesis examines the flow of very viscous Newtonian fluids driven by gravity. It is written with concern for specific applications in the optics industry, with emphasis on the slumping of molten glass into a mould, as in the manufacture of optical components, which are in turn used to manufacture ophthalmic lenses. This process is known as thermal replication. However, the work has more general applicability, and disc viscometry, used to determine the viscosity of very viscous fluids, is also considered. In addition, one chapter of the thesis is devoted to the flow of dripping honey, as another example of a very viscous flow to which the model can be applied. The Stokes creeping-flow equations are used to model the very viscous flows of interest. The main solution method is finite elements, and a purpose-written computer program has been developed to solve the creeping-flow equations by this method. The present program is restricted to solving for either two-dimensional or axisymmetric flows but is extendible to three dimensions. In addition, semi-analytic series and asymptotic methods are used for some small portions of the work. The optical applications of this work demand consideration of the topic of computing surface curvature, and therefore second derivatives, from inexact and discrete numerical and experimental data. For this purpose, fitting of B-splines by a least-squares method to coordinate data defining the surface has been used. Much of the work assumes isothermal conditions, but in the context of the accuracy required in optical component manufacture it is also possible that non-isothermal effects will be important. Consequently, this restriction is eventually relaxed and some consideration given to non-isothermal conditions. In order to validate the creeping-flow model and finite-element program, comparisons of numerical simulations with experimental results are performed. A preliminary assessment of the importance of non-isothermal conditions to the thermal-replication process is also made by comparing isothermal and non-isothermal simulations with experimental results. The isothermal model is found to best match the experimental data. / Thesis (Ph.D.)--School of Applied Mathematics, 1998.

Infiltration of highly concentrated solutions into unsaturated sand is suspected to be affected by the liquid-gas interfacial tension between the resident water and that of the infiltrating solution. The wetting of non-porous solid surfaces by liquids is commonly quantified by contact angle measurements. However, it is well known that wettability of porous solids cannot be accurately obtained by optical inspection because the liquid is penetrating into the pores of the solid in question. The main objective of this investigation was to find an effective method to measure contact angle in coarse porous media such as sandy soils. In this study, we compare both static and dynamic methods to estimate the contact angle formed by solutions of varying surface tension on silica sands. In addition, the contact angle of the imbibing solutions is estimated in both dry and water-wetted sand. Experiments in this study employed three clear acrylic columns of known volume to determine contact angles using two methods, one static method and one dynamic method. The three acrylic columns were packed with the same mass of each grade of Accusand�� (40/50, 30/40, 20/30, and 12/20 grades respectively) for triplicate measurements. The solutions used in this study included (1) pure water and (2) 5 molal NaNO��� and (3) n-hexane as a reference. The static method estimated contact angles in initially dry sand of 23�� for 40/50 sand, and 30�� to 33�� for 12/20, 20/30, and 30/40 sands, with the same values obtained for both solutions. Contact angles of these solutions observed in the dynamic test, were twice those found in the static test (averaging 45�� and 62�� respectively). In the case of pre-wetted sands, dynamic imbibition with water provided an estimated contact angle of 2��, while the NaNO��� solution yielded 21�� contact. Based on relative surface tensions of water and the 5 molal NaNO���, the Young's equation predicts a contact angle of 25��. These results strongly support recent claims of effective contact angles between these miscible, but contracting, fluids. The observed data suggest that the zero contact angle assumption is a poor one even for clean dry silica sand. In a dynamic system, gravitational forces cannot be ignored in course porous media. An analytical method, used to model imbibition of the solutions into the silica sands, was both accurate and useful for estimating contact angle. / Graduation date: 2002

Aluminum based amorphous metallic glass powders were produced and tested as the anode materials for the lithium ion rechargeable batteries. Ground Al₈₀Ni&#x2081₀La&#x2081₀ was found to have a low first cycle capacity of about 100 Ah/Kg. The considerable amount of intermetallic formed in the amorphous glass makes the aluminum inactive towards the lithium. The ball milled Al₈₈Ni₉Y₃ powders contain pure aluminum crystalline particles in the amorphous matrix and have first cycle capacity of about 500 Ah/Kg. Nevertheless, polarization was caused by oxidation introduced by the ball-milling process. The electrochemical performances of these amorphous metallic glasses need to be further investigated. Their full lithium insertion capacities cannot be confirmed until the compositions and particle size inside the metallic glass anodes, the conformation of the electrodes and the mechanical milling processes are optimized. / Singapore-MIT Alliance (SMA)

Europium-doped-fluorochlorozirconate glass ceramics, known as ZBLAN, were produced in a glove box which has a controlled environment of argon gas. For imaging applications BaCl2 is used instead of BaF2. Their properties after different thermal processing and different amounts of europium-doping were investigated. After annealing the ZBLAN glass, BaCl2 nanoparticles are precipitated in the glass matrix. These glass ceramic storage phosphors are strong candidates for replacing traditional x-ray screen film system and commercial storage phosphors such as Agfa MD-30. Differential scanning calorimetry (DSC) was used to determine the crystallization temperature of the hexagonal phase of BaCl2, and orthorhombic BaCl2 this in turn determines the subsequent annealing temperature. X-ray diffraction (XRD) and photoluminescence (PL) show that the hexagonal phase of BaCl2 was formed upon annealing at temperatures between 250 °C and 280 °C for 5 minutes. The orthorhombic phase of BaCl2, which has storage properties, was formed at higher annealing temperatures, at approximately 290 °C and above. Secondary ion mass spectroscopy (SIMS) was used to determine adsorbed/diffused oxygen content of the glass. The weight loss of fluorine and chlorine is 3-5 % and was determined using ion chromatography (IC). The concentration of other cations was determined using inductively coupled plasma spectroscopy (ICP). Transmission electron microscopy (TEM) was used to take high resolution pictures and verify the composition of BaCl2 nanoparticles. The relative concentration of Eu2+ to Eu3+ of heated EuCl3 and ZBLAN was studied using Mössbauer spectroscopy. The oxidation of Eu2+ to Eu3+ was also observed during the experiment. This study has reinforced the strong potential for application of glass-ceramic storage phosphors for medical imaging.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 258-283).

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.