An artificial neural network (ANN) method was developed for solving boundary value problems (BVPs) on an arbitrary irregular domain in such a manner that all Dirichlet and/or Neuman boundary conditions (BCs) are automatically satisfied. Exact satisfaction of BCs is not available with traditional numerical solution techniques such as the finite element method (FEM). The ANN is trained by reducing error in the given differential equation (DE) at certain points within the domain. Selection of these points is significantly simpler than the often difficult definition of meshes for the FEM. The approximate solution is continuous and differentiable, and can be evaluated at any location in the domain independent of the set of points used for training. The continuous solution eliminates interpolation required of discrete solutions produced by the FEM. Reducing error in the DE at a particular location in the domain does not necessarily imply improvement in the approximate solution there. A theorem was developed, proving that the solution will improve whenever error in the DE is reduced at all locations in the domain during training. The actual training of ANNs reasonably approximates the assumptions required by the proof. This dissertation offers a significant contribution to the field by developing a method for solving BVPs where all BCs are automatically satisfied. It had already been established in the literature that such automatic BC satisfaction is beneficial when solving problems on rectangular domains, but this dissertation presents the first method applying the technique to irregular domain shapes. This was accomplished by developing an innovative length factor. Length factors ensure BC satisfaction extrapolate the values at Dirichlet boundaries into the domain, providing a solid starting point for ANN training to begin. The resulting method has been successful at solving even nonlinear and non-homogenous BVPs to accuracy sufficient for typical engineering applications.

In this work, ultrafine-grained (UFG) Al-5wt%Zn alloy was produced by equal channel angular extrusion (ECAE). The microstructure evolution during ECAE and the mechanical properties of the UFG Al-Zn alloy were investigated. In order to identify the effect of Zn in the Al-Zn alloy, pure aluminum (4N, 99.99%) was also studied for comparison. The grains of the Al-Zn alloy could be refined effectively by increasing the ECAE passes. However, as the ECAE passes increased, the microhardness increased initially but maintained constant after 4 ECAE passes. The dislocation density within grain interior was decreased gradually with increasing ECAE passes. After being processed to twelve ECAE passes, the UFG Al-Zn alloy exhibited 53.7% of the grain boundaries being high angle grain boundaries (HAGBs). The UFG Al-5wt%Zn alloy exhibits superior tensile strength and elongation as compared with pure aluminum fabricated by the same ECAE process. Experimental results indicated that adding Zn in aluminum alloy could provide solid-solution strengthening and considerable enhancement in tensile ductility which might be related to an improved post-uniform elongation (PUE). The strain rate sensitivity (SRS) of the UFG Al-Zn alloy also increased with increasing the ECAE passes, which might be related to the fine grain size and the contribution of grain boundary sliding. The activation volume of the UFG Al-Zn alloy was in the range of 32b3~76b3, and the pure aluminum was in the range of 57b3~122b3. Because of the small value of the activation volume, it is suggested that the controlling mechanism for dislocation glide in the UFG Al-Zn alloy might be related to the generation and absorption of dislocations in grain boundary, as well as the interaction between dislocations and solute Zn atoms in the grain boundary.

The increasing clock speed and the further reduction of the feature size in integrated circuits lead to increasing demands on the interconnecting material. Thus an increasing need for a metallization with low electrical resistance and high electromigration endurance exist. Copper can be count as a material with these properties. Since 1998 Copper interconnections are commercially manufactured for integrated circuits. Electromigration is the most lifetime limiting factor in modern integrated circuits. The main the electromigration behavior influencing parameter and especially the influence of the microstructure is unknown. In this work the influence of the grain boundaries and their properties on the electromigration is examined at sputtered (PVD) and electroplated (ECD) Copper interconnects. For this investigation microstructure mappings produced by electron backscatter diffraction (EBSD) are correlated to in-situ electromigration experiments inside the SEM to research the electromigration behavior and the diffusion paths. Microstructure analysis shows big a difference between the two investigated types of interconnects. In both a strong <111> fibre texture is observed, but the PVD Copper shows a stronger texture than the electroplated one. The texture index of the PVD interconnects is 15,9 whereas the ECD lines show an index of 3,9. The frequency densities of the grain boundary misorientation, which is important for the electromigration behavior, are very different for both films. The ECD lines show a fraction of 55% Sigma 3 twin boundaries and 40% high angle grain boundaries. In contrast the PVD interconnects show a fraction of 5% Sigma 3 twin boundaries, 75% high angle grain boundaries and 20% small angle grain boundaries. This shows that a reduction of the high angle grain boundaries is not related to a strong <111> fibre texture. With in-situ experiments correlated to microstructure analysis it is shown, that voiding at high angle grain boundaries occur in the down wind of blocking grains or sites where only Sigma 3 twin boundaries are present. Hillocks were formed at high angle grain boundaries in the upwind of blocking grains or sites where only small angle grain boundaries or Sigma 3 twin boundaries are found. By a statistical evaluation of the in-situ experiments it is shown that more than 50% of the observed electromigration damages could be ascribed clearly to a grain boundary related local mass flux divergence. At strings of high angle grain boundaries voiding at the cathode side and hillock growth at the anode side is shown. The distance between these voids and hillocks is always higher than the Blech length. As the current density increases the distance between these voids and hillocks decreases according to Blech´s law, whereby it´s valid for local divergence is shown. FIB cuts show, that hillocks on PVD lines grow non-epitaxial in contrast to hillocks on ECD lines, which show epitaxial growth. These differences of hillock´s growth may suggest different underlying growth mechanisms. Reliability testing performed on PVD Copper interconnects lead to an activation energy for electromigration of 0,77eV ± 0,07eV. The confidence interval includes reported values for surface and also grain boundary diffusion. This indicates that the electromigration in these experiments is mainly influenced by surface and grain boundary diffusion. In this work the nucleation of voids and hillocks related to the previous analysed microstructure is observed inside the SEM and correlated to high angle grain boundaries and their misorientation angle. The result of this work show that electromigration damage in Copper interconnects is mostly caused by inhomogeneities of the microstructure. In this process the high angle grain boundaries are the main diffusion path. / Mit steigender Taktrate u. weiter fortschreitender Integrationsdichte in mikroelektr. Schaltungen nehmen d. Anforderungen an d. Metallisierungsmaterial weiter zu. Es besteht d. zunehmende Forderung nach Metallisierungen mit geringem elektrischen Widerstand u. hoher Elektromigra- tionsfestigkeit. Kupfer kann als Material angesehen werden, welches d. Anforderungen erfüllt. Seit 1998 wird Kupfer als Metallisierungsmaterial in höchstintegr. Schaltun- gen eingesetzt. Die Elektromigration (EM) ist der d. Zuver- lässigkeit am meisten begrenzende Faktor in mod. mikro- elektron. Schaltungen. Die Haupteinflußgrößen auf d. Elektromigrationsverhalten u. insbes. d. Einfluß d. Gefüges ist unklar. In d. Arbeit wird an nichtpassivier- ten physikalisch (PVD) u. galvanisch (ECD) abgeschied. Kupferleitbahnen d. Einfluß d. Korngrenzen u. deren Eigenschaften auf d. Elektromigrationsverhalten untersucht. Dazu werden Gefügeanalysen mittels Kikuchi-Rückstreutechnik u. in-situ Elektromigrationsexperimente im Rasterelektron- enmikroskop gekoppelt, um d. Elektromigrationsverhalten u. d. Migrationspfade zu erforschen. Gefügeuntersuchungen zeigen, daß d. untersuchten Leitbahnen sich in ihren Gefügeeigenschaften deutl. unterscheiden. Beide Schichten zeigen e. <111> Fasertextur, wobei d. PVD-Leitbahnen e. deutl. schärfere Textur mit e. Texturfaktor von 15,9 gegenüber den ECD-Leitbahnen d. e. Texturfaktor von 3,9 aufweisen. Die Häufigkeitsverteilungen d. Korngrenz- Misorientierung, sind für d. beiden Schichten unterschiedl. Die ECD-Leitbahnen zeigen e. Anteil von 55% Sigma 3-Korngrenzen und 40% Großwinkelkorngrenzen. Die PVD- Leitbahnen hingegen weisen nur e. Anteil von 5% Sigma 3-Korngrenzen, 75% Großwinkelkorngrenzen u. 20% Kleinwin- kelkorngrenzen auf. Dadurch wird gezeigt, daß e. scharfe <111> Textur keine Reduzierung d. Großwinkelkorngrenzen zur Folge haben muß. Anhand von in-situ Experimenten gekoppelt mit Gefügeanalysen wird gezeigt, daß Porenbildung an Groß- winkelkorngrenzen hinter blockierenden Körnern oder hinter Bereichen auftritt, in d. nur Sigma 3-Korngrenzen o. Kleinwinkelkorngrenzen vorliegen. Hügelbildung tritt an Großwinkelkorngrenzen vor blockierenden Körnern o. Berei- chen auf, in denen nur Kleinwinkelkorngrenzen o. Sigma 3-Korngrenzen vorliegen. Mit e. statist. Auswertung d. in-situ Experimente wird gezeigt, daß mehr als d. Hälfte aller Elektromigrationsschädigungen bei beiden Herstellungsmethoden eindeutig auf e. korngrenzbedingte lokale Divergenz im Massenfluß zurückzuführen sind. An Ketten von Großwinkelkorngrenzen wird verdeutl., daß kathodenseitig Porenbildung und anodenseitig Hügelbildung auftritt. Der Abstand zw. Pore u. Hügel liegt hier immer oberh. d. Blechlänge. Mit zunehmender Stromdichte nimmt d. Pore-Hügel-Abstand entspr. d. Blechtheorie ab, wodurch gezeigt wird, daß d. Blechtheorie auch bei lokalen Flußdivergenzen gilt. FIB-Querschnittsanalysen zeigen, daß Hügel auf PVD-Leitbahnen nicht epitaktisch mit d. darunterliegenden Schicht verwachsen sind im Gegensatz zu Hügeln auf ECD-Leitbahnen, die teilw. e. epitaktische Verwachsung mit d. Leitbahn zeigen. Lebensdauermessungen an PVD-Leitbahnen ergeben e. Aktivierungsenergie von 0,77eV ± 0,07eV. Es ist davon auszugehen, daß das Elektromigrationsverhalten d. hier untersuchten unpassi- vierten Leitbahnen haupts. von Korngrenz- u. von Oberfläch- endiffusion beeinflußt wird. In d. Arbeit wurde zum ersten Mal an Kupferleitbahnen d. Entstehung von eit- bahnschädigungen im Zusammenhang mit dem vorher aufgenomme- nen Gefüge im Rasterelektronenmikroskop direkt beobachtet u. mit d. Korngrenzen u. d. Korngrenzwinkeln in Zusammenhang gebracht. Die Ergebnisse d. Arbeit zeigen, daß Schädigungen durch Elektromigration in Kupferleitbahnen vorw. durch Gefügeinhomogenitäten entstehen. Bei d. Prozeß sind Großwinkelkorngrenzen d. bevorzugte Diffusionspfad.

In this work, electrical transport properties and the maximum current carrying capability of YBa2Cu3O7-[delta] thin films and so called quasi-multilayers are investigated. These samples are prepared with pulsed laser deposition on single-crystalline substrates (SrTiO3) as well as on biaxially textured Ni tapes. The critical current density of coated conductors is limited by small-angle grain boundaries in low magnetic fields, but by the intra-grain pinning properties in higher magnetic fields. Accordingly, these investigations are divided into two parts: In the first part, the limitation of the critical current density by grain-boundaries and grain boundary networks is investigated with the main focus on the influence of geometrical factors such as the conductor width or the grain aspect ratio. In the second part, a possible enhancement of the critical current density due to different doping types (atomar doping using Zn and precipitate doping using BaMO3 where M is a transition metal) will be discussed. Here, not only the irreversibility field but also the pinning behaviour in very low magnetic fields is of interest to better understand the pinning mechanism of thin films. / In der vorliegenden Arbeit werden elektrische Transporteigenschaften und die maximale Stromtragfähigkeit von YBa2Cu3O7-[delta]-Dünnschichten und -Schichtsystemen, die mit Hilfe der gepulsten Laserdeposition sowohl auf einkristallinem Substrat, SrTiO3, als auch auf biaxial texturierten Ni-Bändern deponiert wurden, untersucht. Da in kleinen Magnetfeldern Kleinwinkelkorngrenzen die kritische Stromdichte in Bandleitern begrenzen, in höheren jedoch die Pinningeigenschaften der Körner, gliedern sich diese Untersuchungen in zwei Teile: Im ersten wird die Limitierung der kritischen Stromdichte jc durch Korngrenzen und Korngrenzennetzwerke näher untersucht, wobei besonders Geometrieeinflüsse, wie die Leiterbahnbreite oder das Aspektverhältnis der Körner, interessieren. Im zweiten wird eine mögliche Erhöhung der kritischen Stromdichte durch verschiedene Dotierungen (atomare Dotierung: Zn, Ausscheidungsdotierung: BaMO3, M Metall) erörtert. Dabei ist nicht nur das Irreversibilitätsfeld interessant, sondern auch das Pinningverhalten in sehr kleinen Magnetfeldern, da so die Pinningmechanismen in Dünnschichten besser verstanden werden können.

<p>We investigate a certain epidemics model, with and without noise. Some parameter analysis is performed together with computer simulations. The model was presented in Iacus (2008).</p>

This thesis explores multiscale approaches to describe structural and chemical defects in metals. Particular emphasis is placed on investigating processes involving grain boundaries (GBs) in combination with impurity and vacancy defects. The defects and their interactions are calculated to very high accuracy using density functional theory (DFT) and connected to the macroscopic behavior within the two multiscale formalisms presented here. We begin with a sequential approach to address chemical embrittlement of nickel by sulfur impurities. Effects at both a \(\Sigma 5 (012)\) symmetric tilt GB and in the bulk are studied by considering competing mechanisms for ductile and brittle behavior. For the bulk, this takes the form of Rice’s theory, where the ratio of the surface and unstable stacking energy is used as a measure of ductility. This is generalized to the GB by considering GB sliding (GBS) and intergranular decohesion. Clear evidence that chemical embrittlement of nickel by sulfur is a GB driven effect is found. Next, a concurrent multiscale approach is described. A small region, containing the defects, is treated with Kohn-Sham DFT and coupled to the bulk, described with the embedded atom method. We apply this novel method to elucidate the chemical embrittlement of a copper \(\Sigma 5 (012)\) symmetric tilt GB. Intergranular decohesion for three substitutional impurities, bismuth, lead and silver, is investigated by considering the work of separation \((W_s)\) and the tensile strength \((\sigma_t)\). Bismuth and lead show a significant decrease in \(W_s\) and \(\sigma_t\), consistent with embrittlement, whilst silver has only a minor effect. Then, the concurrent multiscale method is applied to the process of GBS in copper. It is found that the resistance against sliding increases significantly for bismuth, lead and silver impurities. The underlying mechanisms for this increase are found to be dominated by size effects for bismuth and lead. For silver, chemical effects are of greater importance. Similar results are found for the underlying mechanisms of intergranular decohesion. The effect of a mono-vacancy on GBS is studied for copper. The multiscale approach enables improved decoupling of the mono-vacancy. It is found that the monovacancy enhances GBS by 22%. / Engineering and Applied Sciences

Ungdomar på hem för Vård eller Boende (HVB-hem) har ofta problematiskt beteende och är i behov av skydd, säkerhet och gränssättning. HVB-hem förväntas utifrån lagstiftning bereda ungdomar vård och behandling för att motverka en ogynnsam utveckling. Inspektionen för vård och omsorg (IVO) ansvarar för tillsynen över verksamheterna. Syftet med föreliggande studie var att intervjua personal på HVB-hem och tillsynsmyndigheten IVO för att undersöka deras uppfattning om hur vård och behandling på HVB-hem bör bedrivas. Vidare syftade studien till att urskilja huruvida lagstiftningen kan tolkas på olika sätt och vilka konsekvenser detta får för vården och behandlingen för ungdomar avseende deras behov av gynnsam psykosocial utveckling. För att erhålla data genomfördes fem kvalitativa intervjuer med yrkesverksamma på HVB-hem och en kvalitativ intervju med två tillsynsinspektörer från IVO. Resultatet analyserades utifrån teoretiska begreppen psykosocial utveckling, motivation och gränssättning och visar att ungdomars behov för att utvecklas psykosocialt består av individuell vård, delaktighet, gränssättning samt verktyg att hantera och skydda sig själva. Vidare visar resultatet att det förekommer hinder och möjligheter i personalens handlingsutrymme för att uppnå detta. Personal upplever frustration över hur tillsynen utförs och anser att deras handlingsutrymme begränsas då personalen och IVO har olika syn på lagstiftningen och hur personalen ska behandla den problematik som ungdomar på HVB-hem uppvisar. En problematiserande diskussion förs angående ungdomars problematik, gränssättning och personalens handlingsutrymme i relation till tillsynens utförande och de två olika tolkningarna av lagstiftningen som delvis står i motsättning till varandra. / Youths in Residential Institutions (HVB-home) often have a problematic behavior and are in need of protection, security and boundaries. HVB-homes are through legislation required to provide care and treatment to counteract adverse development among the youth. The Inspection for Health and Care (IVO) supervise the HVB-homes. The purpose of this study was to interview staff at HVB-homes and Inspectors at IVO to investigate their perceptions of how care and treatment should be conducted. Furthermore the aim was to distinguish whether the legislation can be interpreted differently and what consequences this has for the care and the treatment for the youths regarding their needs for positive psychosocial development. To obtain data five qualitative interviews were conducted with professionals at HVB-homes and one with two inspectors at IVO. The result was analyzed according to the theoretical concepts of psychosocial development, motivation and boundaries. The result shows that to develop psychosocial maturity, young people need individual care, empowerment, boundaries and skills to control and protect themselves. Furthermore, it shows occurrences of both obstacles and opportunities in terms of the staff being able to provide the appropriate care for the youth. The staff experience frustration in the execution of the supervision and describe that they interpret the legislation differently from IVO. The staff express that they are unable to handle the youths at HVB-home. A problematizing discussion is conducted regarding the youths’ problems at HVB-homes, need of boundaries and the staffs’ ability to provide appropriate care in relation to the execution of the supervision and the two partly different interpretations of the legislation.

Baigiamajame darbe nagrinėjami nekilnojamojo turto kadastro žemėlapio žemės sklypų ribų topologiniai nesutapimai, atsirandantys dėl riboženklių koordinačių netikslumų. Nagrinėjama bendras ribas turinčių 5 žemės sklypų grupė, kurios ribos nustatytos kadastrinių matavimu metu, valstybinėje koordinačių sistemoje. Matavimais gautos tų pačių riboženklių koordinačių reikšmės nesutapma dydžiu, kuris yra ne didesnis kaip teisės aktais reglamentuojamas leistinas riboženklių nesutapimas. Nesutapimams panaikinti atliekamas žemės sklypų koordinčių optimizavimas genetinio algoritmo metodu. Optimizavimo uždavinui suformuluoti pasirinkta optimizavimo sąlygą ir ribojimų sistema, paremti teisės aktų reikalavimais. Atliekamas nesutampančių koordinačių optimizavimas, rezultatai analizuojami pagal žemės sklypų plotų pokyčius. Darbe pateikiami tyrimo rezultatai ir išvados. Darbą sudaro: įvadas, keturi skyriai, išvados, literatūros sąrašas. Darbo apimtis - 82 p. Teksto be priedų, 25 iliustr., 33 lent., 25 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / In the final work of Master’s degree are analysed topological misalignments between Real Estate Cadastral Map parcel boundaries, that occures due to imprecision of landmark coordinates. The investigation involves a group of 5 parcels with common boundaries, whose cadastral measurements were carried out in the national system of geodetic coordinates. Measured same landmark coordinates, satisfies the required juridical difference between the coordinates of common boundary marks. In order to liquidate misalignments of parcel boundaries, genetic algorithm optimization method of land coordinates is performed. On purpose to develop optimization task, the optimization condition and limitation system were chosen, according to the juridical requirements. The optimization of misaligned coordinates is performed, results of this investigation are analysed by differences of parcel area. Structure: introduction, four sections, conclusions, references. Final work consist of 82 p. text without extras, 25 pictures, 33 tables, 25 bibliographical entries. Appendixes included.

As the world shifts and changes, so do its people, and every day, more refugees are forced out-of-place, out of their homelands, and into a foreign and unfamiliar context. Many of these refugees are women, single mothers, who along with their children, are set to face many challenges in the process of re-settling into a new cultural landscape. This project is a study on how the design of an interior can aid in the difficult process of transitioning between lands and cultures. Within it, I explore the making of place through the design of a transitional residence for women and children refugees, set within the dynamic urban landscape of West Broadway in Winnipeg, Manitoba. I proceed through this project through an exploration of four conceptual frameworks and examine the project and its users in relation to movement and migration, to boundaries, to the contact zone, and finally to weaving.

The purpose of this paper is to investigate segregation from an accommodation perspective. The essay questions how the residents of Ronna feel about their neighborhood and what they think of other people's views of their area. Our purpose is to conduct a qualitative study of whether or not individuals experience residential segregation in Ronna. The essay is based on qualitative interviews, which were conducted with five people who have lived in Ronna for at least five years and who define themselves as Assyrians/Syrians. To analyze our empirical data, we have used two theoretical perspectives. One by Westin and Elias &amp; Scotson, which is the theory about social groups - established and outsiders. The second theory explains how ethnic boundaries and enclaves occur. With the support of previous research, we highlight and define the fundamental factors causing segregation. After analyzing our empirical data, we concluded that residential segregation is a broad concept and that there are several factors that lead to segregation. The result of the study indicates that all informants thrive in their neighborhood and feel a solidarity and cohesion with each other. In Ronna the Assyrian/Syrian is a dominant ethnic community which has formed a strong “We” – group in their neighborhood. / Syfte med denna studie är att belysa boendesegregationen i Ronna ur de boendes perspektiv. Med stöd av några teoretiska perspektiv besvaras frågan om hur invånare i Ronna upplever sitt bostadsområde, samt hur de förhåller sig till andras uppfattningar och föreställningar om sitt område.Studiens syfte uppnås genom en kvalitativ studie om individers upplevelser kring boendesegregationen i Ronna. Uppsatsen är uppbyggd utifrån kvalitativa intervjuer, vilka har genomförts med fem personer i åldrarna 30-45 som för närvarande bor i Ronna sedan minst fem år tillbaka, alla dessa individer definierar sig som assyrier/syrianer. För att analysera intervjumaterialet har vi använt oss av två teoretiska perspektiv. Den ena av dessa är det samhällsvetenskapliga forskningsinriktning som studerar sociala grupper - etablerade och outsiders, därefter har denna teori kompletterats med ett ytterligare teoretiskt perspektiv som redogör för hur etniska gränser och enklaver uppstår. Med hjälp av tidigare forskning belysas och definieras olika bakomliggande faktorer som kan orsaka boendesegregation inom ett bostadsområde. Analysen av intervjumaterialet visar att boendesegregation är ett omfattande fenomen där flera faktorer ger upphov till att segregation uppstår. Studieresultatet påvisar att i Ronna är assyrier/syrianer en dominerande folkgrupp som har skapat en stark vi-grupp i sitt bostadsområde. Samtliga informanter trivs bra i sitt bostadsområde, samt känner en stark gemenskap och tillhörighet.