Nano-scale machining, or Nanomachining is a hybrid process in which the total thermal energy necessary to remove atoms from a work-piece surface is applied from external sources. In the current study, the total thermal energy necessary to remove atoms from a work-piece surface is applied from two sources: (1) localized energy from a laser beam focused to a micron-scale spot to preheat the work-piece, and (2) a high-precision electron-beam emitted from the tips of carbon nano-tubes to remove material via evaporation/sublimation. Macro-to-nano scale heat transfer models are discussed for understanding their capability to capture and its application to predict the transient heat transfer mechanism required for nano-machining. In this case, thermal transport mechanism during nano-scale machining involves both phonons (lattice vibrations) and electrons; it is modeled using a parabolic two-step (PTS) model, which accounts for the time lag between these energy carriers. A numerical algorithm is developed for the solution of the PTS model based on explicit and implicit finite-difference methods. Since numerical solution for simulation of nanomachining involves high computational cost in terms of wall clock time consumed, performance comparison over a wide range of numerical techniques has been done to devise an efficient numerical solution procedure. Gauss-Seidel (GS), successive over relaxation (SOR), conjugate gradient (CG), d -form Douglas-Gunn time splitting, and other methods have been used to compare the computational cost involved in these methods. Use of the Douglas-Gunn time splitting in the solution of 3D time-dependent heat transport equations appears to be optimal especially as problem size (number of spatial grid points and/or required number of time steps) becomes large. Parallel computing is implemented to further reduce the wall clock time required for the complete simulation of nanomachining process. Domain decomposition with inter-processor communication using Message Passing Interface (MPI) libraries is adapted for parallel computing. Performance tuning has been implemented for efficient parallelization by overlapping communication with computation. Numerical solution for laser source and electron-beam source with different Gaussian distribution are presented. Performance of the parallel code is tested on four distinct computer cluster architecture. Results obtained for laser source agree well with available experimental data in the literature. The results for electron-beam source are self-consistent; nevertheless, they need to be validated experimentally.

Tato dizertační práce se zabývá modelováním mikrovlnných polovodičových struktur. Stále vyšší pracovní kmitočty komunikačních systémů zvyšují nároky na aktivní prvky a přenosová vedení, realizované zpravidla v monolitické integrované podobě. Přenosová vedení s rozprostřeným zesílením představují perspektivní řešení nejen jako zesilovací prvky, ale také jako aktivní napáječe mikrovlnných antén. V součastné době neexistuje vhodný softwarový nástroj pro jejich efektivní simulaci a návrh. První část této práce je zaměřena na implementaci termodynamické formulace modelu driftu a difuze pro numerickou simulaci transportních procesů polovodičových struktur v komerčním programu COMSOL Multiphysics. Další část je věnována implementaci Gunnova jevu v makroskopické aproximaci a vypracování simulační procedury pro analýzu struktur využívajících tento jev. Poslední část je věnována návrhu a analýze aktivních přenosových vedení a zlepšení jejich vlastností.

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Introduction Estrogen-induced cholestasis is a disease characterized by a failure of bile flow and bile production. It can develop in women after oral contraceptives use, hormone replacement therapy or during pregnancy. The estrogen metabolism is a complex process leading to formation of metabolites with different biological activities. It takes place primarily in the liver (Phase I and Phase II including hydroxylation, methylation, sulfation and glucuronidation). The enzymes from UDP-glucuronosyltransferases family , abbreviated UGT, are responsible for the glucuronidation of estrogens. Aims The objective of my work is to define estrogen metabolism and gene expression of UGT1A1, CYP1A2 and SULT1A1 and characterize cholestatic liver damage in the UGT1A1 deficient rat strain (Gunn rats) compared to rats with normal enzyme activity and try to define possible mechanisms responsible for the liver damage. Methods Adult female Gunn and corresponding heterozygous rats were treated with ethinylestradiol (EE, 5 mg/kg body weight SC) for 5 days, while control rats received propanediol (vehicle). Day six, the animals were sacrificed and plasma and liver tissue were collected for analysis. Markers of cholestasis and liver damage ALP, AST, ALT and bilirubin were determined using an automatic analyzer, total...

Ultra-fast laser heating of nano-films is investigated using 3-D Dual Phase Lag heat transport equation with laser heating at different locations on the metal film. The energy absorption rate, which is used to model femtosecond laser heating, is modified to accommodate for three-dimensional laser heating. A numerical solution based on an explicit finite-difference method is employed to solve the DPL equation. The stability criterion for selecting a time step size is obtained using von Neumann eigenmode analysis, and grid function convergence tests are performed. DPL results are compared with classical diffusion and hyperbolic heat conduction models and significant differences among these three approaches are demonstrated. We also develop an implicit finite-difference scheme of Crank-Nicolson type for solving 1-D and 3-D DPL equations. The proposed numerical technique solves one equation unlike other techniques available in the literature, which split the DPL equation into a system of two equations and then apply discretization. Stability analysis is performed using a von Neumann stability analysis. In 3-D, the discretized equation is solved using delta-form Douglas and Gunn time splitting. The performance of the proposed numerical technique is compared with the numerical techniques available in the literature.

Techn. Universiẗat, Diss., 2002--Dresden.

Since Native American Literature has been established, Native American authors have discussed the influence of the western world on Native traditions and Native identity within their work. Christianity is one of those elements of western cultural influences that shaped remarkably the change of Native traditions under the influence of colonialism. In this dissertation it will be discussed how the influence of Christianity is being written into the novels by Native American writers and which functions are attributed to Christianity in respect to the enforcement of colonial interests and in respect to changes within Native traditions. For this dissertation four authors (D'Arcy McNickle, Paula Gunn Allen, N. Scott Momaday, Louise Erdrich) were chosen whose pieces of work mark a difference in approach. Their novels testify to the contradictory fusion of colonial and missionary goals on the one side and to the possible enrichment of Native customs on the other side. The novels can, therefore, be characterized as an assemble that reaches from total rejection of anything that is assumed to be Christian to an affirmative way of incorporating selective aspects of Christianity to the final denial that there is an evaluation of this historical issue possible. In respect to the method applied, all pieces of literary work are discussed in their usage of Christian literary elements and intertextual references to the Bible and other Christian literary sources. An afterword refers to novels and short stories by further 17 Native American authors who are concerned with the Christian influence on Native traditions in their work as well. The results of the research in the dissertation will then be extended by discussing those pieces of fictional work. / Seit der Etablierung des indianischen Romans im Kanon der amerikanischen Gegenwartsliteratur suchen indianische Schriftsteller nach Wegen, die doppelte Prägung der modernen indianischen Identität durch traditionelle Werte einerseits und westlichen Einfluss andererseits fiktional aufzuarbeiten. Ein Element der westlichen Welt, das die Veränderungen der indianischen Kulturen unter der Einwirkung der Kolonisation maßgeblich mitbestimmt hat, ist die christliche Religion. In der Dissertation wird untersucht, wie das Wirken des Christentums auf das indigene Selbstbild in der US-amerikanischen indianischen Romanliteratur thematisiert wird und welche Funktionen ihm für die Durchsetzung kolonialer Interessen und für den Wandel der indianischen Traditionen im Verlauf der letzten 500 Jahre zuerkannt werden. Für die Fragestellung wurden vier Autorinnen und Autoren ausgewählt (D'Arcy McNickle, Paula Gunn Allen, N. Scott Momaday, Louise Erdrich), deren Romanwerke die Gegensätzlichkeit zwischen der Verquickung kolonialer Interessen mit religiösen Motiven einerseits und der Bereicherung der indianischen Kulturen durch christliche Traditionen andererseits widerspiegeln. Die Romane bilden einen Spannungsbogen von strikter Ablehnung alles Christlichen, über die affirmative Aufnahme christlicher Elemente bis hin zur Pluralisierung der Bewertungsmöglichkeiten bei gleichzeitiger Aufgabe der Bewertungsgewissheit hinsichtlich des christlichen Einflusses. Methodisch wird hierbei folgendermaßen vorgegangen. Die Romane werden auf intertextuelle Verweise zu christlichen literarischen Quellen und insbesondere der Bibel untersucht, um daran die Gestaltung des Untersuchungsgegenstandes zu erörtern. Ein ausführlicher Ausblick verweist auf Romane und Erzählungen weiterer 17 indianischer Autorinnen und Autoren der Gegenwart, um hieran die Ergebnisse der Untersuchung zu präzisieren und zu ergänzen.

Since Native American Literature has been established, Native American authors have discussed the influence of the western world on Native traditions and Native identity within their work. Christianity is one of those elements of western cultural influences that shaped remarkably the change of Native traditions under the influence of colonialism. In this dissertation it will be discussed how the influence of Christianity is being written into the novels by Native American writers and which functions are attributed to Christianity in respect to the enforcement of colonial interests and in respect to changes within Native traditions. For this dissertation four authors (D'Arcy McNickle, Paula Gunn Allen, N. Scott Momaday, Louise Erdrich) were chosen whose pieces of work mark a difference in approach. Their novels testify to the contradictory fusion of colonial and missionary goals on the one side and to the possible enrichment of Native customs on the other side. The novels can, therefore, be characterized as an assemble that reaches from total rejection of anything that is assumed to be Christian to an affirmative way of incorporating selective aspects of Christianity to the final denial that there is an evaluation of this historical issue possible. In respect to the method applied, all pieces of literary work are discussed in their usage of Christian literary elements and intertextual references to the Bible and other Christian literary sources. An afterword refers to novels and short stories by further 17 Native American authors who are concerned with the Christian influence on Native traditions in their work as well. The results of the research in the dissertation will then be extended by discussing those pieces of fictional work. / Seit der Etablierung des indianischen Romans im Kanon der amerikanischen Gegenwartsliteratur suchen indianische Schriftsteller nach Wegen, die doppelte Prägung der modernen indianischen Identität durch traditionelle Werte einerseits und westlichen Einfluss andererseits fiktional aufzuarbeiten. Ein Element der westlichen Welt, das die Veränderungen der indianischen Kulturen unter der Einwirkung der Kolonisation maßgeblich mitbestimmt hat, ist die christliche Religion. In der Dissertation wird untersucht, wie das Wirken des Christentums auf das indigene Selbstbild in der US-amerikanischen indianischen Romanliteratur thematisiert wird und welche Funktionen ihm für die Durchsetzung kolonialer Interessen und für den Wandel der indianischen Traditionen im Verlauf der letzten 500 Jahre zuerkannt werden. Für die Fragestellung wurden vier Autorinnen und Autoren ausgewählt (D'Arcy McNickle, Paula Gunn Allen, N. Scott Momaday, Louise Erdrich), deren Romanwerke die Gegensätzlichkeit zwischen der Verquickung kolonialer Interessen mit religiösen Motiven einerseits und der Bereicherung der indianischen Kulturen durch christliche Traditionen andererseits widerspiegeln. Die Romane bilden einen Spannungsbogen von strikter Ablehnung alles Christlichen, über die affirmative Aufnahme christlicher Elemente bis hin zur Pluralisierung der Bewertungsmöglichkeiten bei gleichzeitiger Aufgabe der Bewertungsgewissheit hinsichtlich des christlichen Einflusses. Methodisch wird hierbei folgendermaßen vorgegangen. Die Romane werden auf intertextuelle Verweise zu christlichen literarischen Quellen und insbesondere der Bibel untersucht, um daran die Gestaltung des Untersuchungsgegenstandes zu erörtern. Ein ausführlicher Ausblick verweist auf Romane und Erzählungen weiterer 17 indianischer Autorinnen und Autoren der Gegenwart, um hieran die Ergebnisse der Untersuchung zu präzisieren und zu ergänzen.

Thesis (Ph. D.)--Universität Hamburg, 1993. / Includes bibliographical references (p. 198-212).