Polymer matrix composites reinforced by metal fibers are observed to present an onset of the insulator-to-conductor transition through previous experimental studies. Analytical studies revealed that the percolation threshold occurs when fiber volume fraction reaches the critical value. The numerical study based on Monte Carlo simulations are performed to investigate such a relation. In this work, the conductive fillers are modeled as a three dimensional (3D) network of identical units randomly distributed in the polymer matrix. For the simplest case, straight fibers are used in the simulation. The effects of the aspect ratio and fiber length on the critical volume fraction are also studied. Linearization is made to the logarithm of simulation results. Next, in order to study the effects of emulsion particles and the emulsion particle sizes on the percolation behavior, cubic particles are aligned in the sample model. The gap width to particle size ratio is fixed at 1/10. The calculated critical volume fraction is used in the power-law function to predict the electrical conductivity of the polymer composites. Due to the insensitivity of the thermal conductivity to the percolation threshold, a combination of two empirical equations is used to predict the range of overall thermal conductivity.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references (leaves 182-195). Also available in an electronic version.

1999 Dozier Award Winner / This paper examines critically several key assumptions that have guided many archaeological interpretations of prehistoric mortuary assemblages. It is argued that more sophisticated models of mortuary deposition need to be incorporated into research that attempts to reconstruct community structure and other sociological variables from variation in grave assemblages. To illustrate this point, and to begin to build such models, a study of artifacts deposited in mortuary contexts was conducted by the author in a major urban center in Arizona in 1996. Several different behavioral pathways through which objects enter mortuary contexts are identified in this study, and some general material correlates for each are specified. This study also provides a vehicle for exploring preliminarily how, and to what extent, various forms of mortuary depostion are related to the social identities of the deceased. Finally, a synthetic model is developed which seeks to explain variation in mortuary deposition in terms of behavioral interactions between the living, on the one hand, and the deceased and various classes of material culture, on the other. It is hoped that the general models and material correlates developed through this study can be elaborated by prehistorians to bolster inferences drawn from specific mortuary populations and to explore previously-uncharted realms of mortuary behavior in the past.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

<p> In analyzing the processes involved in neutron radiography, there is a need for a well-defined mathematical structure which can simultaneously be used in practical situations without great difficulty. In this report, the edge-spread function method of analysis is considered in some detail. The basic theory is developed, and both the general and the specific viewpoint are considered, in terms of the mathematical functions used. The usefulness of ESF theory in predicting optical density patterns is illustrated. Specific applications of the theory are developed; in particular, studies of image resolution and unsharpness are undertaken. </p> <p> To determine whether or not ESF methods are a good representation of the physical situation, some alternate methods which consider radiography from a more basic viewpoint are developed. The first of these is a strictly numerical approach, where experimental data is examined without specifying a model for the image formation process; a matrix formulation suitable for characterizing an image is developed. </p> <p> The second alternate method involves the use of Monte Carlo methods; this allows the incorporation of more realistic parameters into the analysis. For example, screen-film separation and object scattering of neutrons, and their effects on the image, are evaluated. Finally, a two-dimensional analysis of a simple problem is considered, with the end result being a confirmation of the usefulness of ESF theory. </p> / Thesis / Master of Engineering (MEngr)

The thesis deals with project management in an advertising agency. It analyzes the current methodology of the agency project management, defines its weak points, and proposes a set of improvements to this methodology. This goal is achieved through analysis of the project management of the agency using the Theory of Constraints methodology and comparison with the methodologies and best practices of the project management in the industry. The first part describes the common project management methodologies, the specifics of the project management in advertising agencies and the Theory of Constraints. The second part analyzes a particular advertising agency using the Theory of Constraints and proposes a set of changes to its methodology, mostly in the area of project planning and project management. The merit and main output of the work consists of the proposed changes to the advertising agency project management methodology.

Quantum mechanics became a foundation for incessant development of versatile computational methods for analysis of chemical and physical properties of molecules and crystals. A huge progress has been made in the fifield of density functional theory, since nowadays this theory offers the best compromise between precision of results and efficiency fiof computation. The chemical bonding analysis can be easily performed with real space methods based on chemical concepts introduced via partitioning of real space into chemically meaningful domains, since the orbital based approach is not well applicable due to the delocalized nature of plane waves. However the practical usage of those methods often requires a signifificant amount of computational resources. Some methods require the evaluation of so called domain overlap matrices, that is a formidable task for complex and low-symmetry systems. In the present research the author enables the investigation of complex solid compounds with real space chemical bonding indicators by introducing the derivation of the expression for the evaluation of the domain overlap matrix elements from the projected-augmented wave method. The corresponding program module was developed, which is capable to perform the real space chemical bonding analysis with a number of methods, like electron localizability indicators, electron localization function, localization/delocalization indices and domain averaged Fermi hole orbitals. The efficiency and the accuracy of the developed implementation is demonstrated by the comparison with the domain overlap matrix elements evaluation from the full-potential linearized augmented plane wave method on a set of simple compounds with three atoms per primitive cell at most. A set of complex periodic structures is analyzed and the capability of the present implementation to unravel intricate chemical bonding patterns is demonstrated.

Der Gegenstand der vorliegenden Arbeit ist die Simulation von Betonstrukturen beliebiger Geometrie unter überwiegender Zugbelastung. Die Modellierung erfolgt auf Makroebene als Kontinuum und zur Lösung des mechanischen Feldproblems wird die Finite-Elemente-Methode verwendet. Ein neues Materialmodell für Beton und eine Erweiterung der Bruchenergetischen Regularisierung werden vorgestellt. Die Arbeit ist in zwei Teile gegliedert. Im ersten Teil wird ein lokales, anisotropes Schädigungsmodell abgeleitet, wobei als Schädigungsvariable ein symmetrischer Tensor zweiter Stufe gewählt wird. Die Verwendung einer Normalenregel im Raum der dissipativen Kräfte zur Bestimmung der Schädigungsevolution und die Definition der Schädigungsgrenzflächen im Raum der dissipativen Kräfte gewährleisten die Gültigkeit der Hauptsätze der Thermodynamik und des Prinzips der maximalen Dissipationsrate. Vorteilhaft ist die Symmetrie der Materialtangente, die sich aus diesem Vorgehen ergibt. Eine Formulierung mit drei entkoppelten Schädigungsgrenzflächen wird vorgeschlagen. Eine wichtige Forderung bei der Ableitung des Materialmodells war die Verwendung einer möglichst geringen Anzahl von Materialparametern, welche darüber hinaus aus wenigen Standardversuchen bestimmbar sein sollten. Das Schädigungsmodell enthält als Materialparameter den Elastizitätsmodul, die Querdehnzahl, die Zugfestigkeit und die auf eine Einheitsfläche bezogene Bruchenergie. Im zweiten Teil der Arbeit stehen Lokalisierung und Regularisierung im Fokus der Betrachtungen. Aufgrund der lokalen Formulierung des Materialmodells tritt bei Finite-Elemente Simulationen eine Netzabhängigkeit der Simulationsergebnisse auf. Um dieser Problematik zu begegnen und netzunabhängige Simulationen zu erreichen, werden Regularisierungstechniken angewendet. In dieser Arbeit wird die Bruchenergetische Regularisierung eingesetzt, die durch die Einführung einer äquivalenten Breite in ein lokal formuliertes Stoffgesetz gekennzeichnet ist. Die spezielle Wahl eines Wertes für die äquivalente Breite beruht auf der Forderung, dass in der Simulation die korrekte Bruchenergie je Einheitsfläche für den Bruchprozess verbraucht wird, d.h. die Energiedissipation der Realität entspricht. In vorliegender Arbeit wird die neue These aufgestellt, dass die Energiedissipation nur für den Fall korrekt abgebildet wird, wenn die im Stoffgesetz enthaltene äquivalente Breite in jedem Belastungsinkrement der Breite des Bereiches entspricht, in dem in der Simulation Energie dissipiert wird. In einer Simulation wird in den Bereichen Energie dissipiert, in denen die Schädigung im aktuellen Belastungsinkrement zunimmt. In vorliegender Arbeit werden die energiedissipierenden Bereiche daher als Pfad der Schädigungsrate bezeichnet. Um Erkenntnisse über die Entwicklung des Pfades der Schädigungsrate über den Belastungsverlauf zu erhalten, wurden umfangreiche Untersuchungen anhand von Simulationen eines beidseitig gekerbten Betonprobekörpers unter kombinierter Zug-Schubbeanspruchung durchgeführt, wobei die gewählten Werte für die äquivalente Breite variiert wurden. Es wurde stets eine Diskretisierung mit linearen Verschiebungselementen verwendet, wobei die Bereiche mit zu erwartender Schädigung feiner und regelmäßig mit Elementen quadratischer Geometrie diskretisiert wurden. Die Ergebnisse der Untersuchungen zeigen, dass die Breite des Pfades der Schädigungsrate abhängig ist von der Schädigung am betrachteten Materialpunkt, dem von Schädigungsrichtung und Elementkante eingeschlossenen Winkel, der Elementgröße und den Materialparametern. Um die geforderte Übereinstimmung von äquivalenter Breite und der Breite des Pfades der Schädigungsrate zu erreichen, werden neue Ansätze für die äquivalente Breite vorgeschlagen, die die erwähnten Einflüsse berücksichtigen. Simulationen unter Verwendung der neuen Ansätze für die äquivalente Breite führen zu einer guten Übereinstimmung von äquivalenter Breite und der Breite des Pfades der Schädigungsrate in der Simulation. Die Ergebnisse der Simulationen, wie z.B. Last-Verformungsbeziehung und Rissverläufe, sind netzunabhängig und stimmen gut mit den experimentellen Beobachtungen überein. Basierend auf den gewonnenen Erkenntnissen wird eine Erweiterung der Bruchenergetischen Regularisierung vorgeschlagen: die Adaptive Bruchenergetische Regularisierung. Im abschließenden Kapitel der Arbeit werden mit der vorgeschlagenen Theorie, dem neuen Schädigungsmodell und der Adaptiven Bruchenergetischen Regularisierung, noch zwei in der Literatur gut dokumentierte Versuche simuliert. Die Simulationsergebnisse entsprechen den experimentellen Beobachtungen. / This doctoral thesis deals with the simulation of predominantly tensile loaded plain concrete structures. Concrete is modeled on the macro level and the Finite Element Method is applied to solve the resulting mechanical field problem. A new material model for concrete based on continuum damage mechanics and an extended regularization technique based on the fracture energy approach are presented. The thesis is subdivided into two parts. In the first part, a local, anisotropic damage model for concrete is derived. This model uses a symmetric second-order tensor as the damage variable, which enables the simulation of orthotropic degradation. The validity of the first and the second law of thermodynamics as well as the validity of the principle of maximum dissipation rate are required. Using a normal rule in the space of the dissipative forces, which are the thermodynamically conjugated variables to the damage variables, and the definition of the loading functions in the space of the dissipative forces guarantee their validity. The suggested formulation contains three decoupled loading functions. A further requirement in the derivation of the model was the minimization of the number of material parameters, which should be determined by a small number of standard experiments. The material parameters of the new damage model are the Young’s modulus, the Poisson’s ratio, the tensile strength and the fracture energy per unit area. The second part of the work focuses on localization and regularization. If a Finite Element simulation is performed using a local material model for concrete, the results of the Finite Element simulation are mesh-dependent. To attain mesh-independent simulations, a regularization technique must be applied. The fracture energy approach, which is characterized by introducing a characteristic length in a locally formulated material model, is used as regularization technique in this work. The choice of a value for the characteristic length is founded by the requirement, that the fracture energy per unit area, which is consumed for the fracture process in the simulation, must be the same as in experiment, i.e. the energy dissipation must be correct. In this dissertation, the new idea is suggested that the correct energy dissipation can be only attained if the characteristic length in the material model coincides in every loading increment with the width of the energy-dissipating zone in the simulation. The energy-dissipating zone in a simulation is formed by the integration points with increasing damage and obtains the name: damage rate path. Detailed investigations based on simulations of a double-edge notched specimen under mixed-mode loading are performed with varying characteristic lengths in order to obtain information concerning the evolution of the damage rate path during a simulation. All simulations were performed using displacement-based elements with four nodes. The range with expected damage was always finer and regularly discretized. The results of the simulations show that the width of the damage rate path depends on the damage at the specific material point, on the angle between damage direction and element edges, on the element size and on the material parameters. Based on these observations, new approaches for the characteristic length are suggested in order to attain the coincidence of the characteristic length with the width of the damage rate path. Simulations by using the new approaches yield a sufficient coincidence of the characteristic length with the width of the damage rate path. The simulations are mesh-independent and the results of the simulation, like load-displacement curves or crack paths, correspond to the experimental results. Based on all new information concerning the regularization technique, an extension of the fracture energy approach is suggested: the adaptive fracture energy approach. The validity and applicability of the suggested theory, the new anisotropic damage model and the adaptive fracture energy approach, are verified in the final chapter of the work with simulations of two additional experiments, which are well documented in the literature. The results of the simulations correspond to the observations in the experiments.

This thesis develops a Theoretical framework to be applied to future research concerning medieval Japanese Buddhist nuns and their involvements with Buddhist material culture. My efforts at theory production serve as a preliminary attempt at laying a comprehensive Theoretical foundation for a fresh area of inquiry, namely merging the respective studies of Japanese Buddhist nuns with Buddhist material culture. This marks a promising area of study as a corrective to the enduring focus placed upon men by Religious Studies (RS) scholars. Indeed, RS has historically been, and largely continues to be, a field dominated by men. As such, RS research has concentrated upon the male population, both lay and monastic, and has only recently started shifting toward the question of where women were and what they were doing. Additionally, the study of Buddhist material culture is itself a relatively new field. Consequently, there are currently very few English publications exploring women’s involvement with this important aspect of Buddhism. As a means of contextualizing the Theoretical framework ultimately proposed, I first examine the states of the Buddhist Studies subfields of Buddhist nuns and of Buddhist material culture. I subsequently explore the states of theory production within RS and Medieval Japanese Buddhist Studies (MJBS), contending that a distinctive mode of theory (macro ‘capital-T’ Theoretical frameworks and micro ‘lowercase-t’ theoretical models, respectively) is found within each discipline. While I propose only a RS style macro Theoretical framework, I suggest that an ideal foundation for the study of nuns through the lens of material culture will take the form of a Theoretical complex comprised of both a Theoretical framework and a MJBS style theoretical model. Ultimately, I wish to begin the process of laying the groundwork for future research focusing on women and gender within the context of Buddhism and material culture. / Thesis / Master of Arts (MA) / This thesis develops a Theoretical framework to be used in future research about medieval Japanese Buddhist nuns and their involvements with Buddhist material culture (paintings, statues, relics, and so on). This is a preliminary attempt at laying a Theoretical foundation for this fresh area of inquiry. In this endeavour, I am trying to respond to the enduring focus placed upon men by Religious Studies (RS) scholars, as the field has been and largely continues to be dominated by men. Consequently, there are very few English publications exploring Buddhist nuns and material culture, an important aspect of Buddhism. I examine the states of the studies of these topics, and explore two types of theory production distinct to RS and Medieval Japanese Buddhist Studies respectively. Ultimately, I wish to begin the process of laying the groundwork for future research on women and gender within the context of Buddhism and material culture.