Sankt Gallen, Univ., Diss., 2003.

FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Neste trabalho, estudamos conceitos de geometria algébrica relacionados a teoria de códigos de Goppa algebricos geometricos (códigos AG). Vimos como o cálculo do semi- grupo de Weierstrass pode ser aplicado na obtencao dos parâmetros de certos cádigos AG. Em particular, calculamos o semigrupo de Weierstrass em dois pontos da curva Xq2r dada pela equacao afim yq + y = xq+1 sobre Fq2r, onde r e um inteiro positivo ímpar e q á uma potencia de um numero primo, e construímos um cádigo AG bipontual sobre Xq2r, cujos parâmetros relativos sao melhores que cádigos AG pontuais comparâveis tambem construídos sobre esta curva. A principal referencia deste trabalho foi [8]. / In this work we study basics concepts of the algebraic geometry related to Algebraic Geometric Goppa codes theory (AG codes). We have seen how the calculation of the Weierstrass semigroup can be applied in obtaining the parameters of certain AG codes. In particular, we calculated the Weierstrass semigroup at two points on the curve Xq2r defined by afim equation yq + y = xq +1 over Fq2r, where r is a positive odd integer and q is a prime power, and construct a two-point AG code over Xq2r whose relative parameters are better than comparable one-point AG code. The main reference of this work was [8]. / Dissertação (Mestrado)

La Réduction Catalytique Sélective des NOx par NH3 est un procédé efficace de dépollution des gaz. Cependant, pour une application sur véhicules Diesel, l'activité à basse température (175-250°C, phase de démarrage du véhicule) reste limitée. De plus, les catalyseurs de NH3-SCR sont sensibles au rapport NO2/NOx, avec un optimum pour NO2/NOx = 0,5. Or, à basse température, la proportion de NO2 est faible car le catalyseur d’oxydation (DOC) placé en amont est également peu actif. L'éthanol (EtOH) est un autre réducteur possible, principalement avec des catalyseurs Ag/Al2O3. Ce système présente également d'une activité limitée à basse température, bien que l'oxydation de EtOH s'accompagne de la formation de NO2. Dans ces travaux, l'association de EtOH et NH3 pour la SCR de NO sur catalyseur Ag/Al2O3 a été étudié. Un effet de synergie a été obtenu, avec un gain important d'activité à basse température. Ce gain ne provient pas directement d'une réaction entre NH3 et EtOH ou ses sous-produits d'oxydation (CH3CHO, CO…), ni uniquement grâce à la réaction entre NO2 (formé par réaction de NO avec EtOH) et NH3. La caractérisation des espèces adsorbées par IRTF et des tests de (H2+NH3)-SCR ont permis de conclure que les espèces H*, provenant de la déshydrogénation de l'éthanol, réagissent avec les NOx pour conduire à des espèces HNOx très réactives avec NH3.Finalement, la mise en œuvre d'un double-lit (2%Ag/Al2O3 + catalyseur de NH3-SCR), afin d'utiliser NH3, NO et NO2 restants, a permis d'obtenir une conversion NOx comprise entre 46 et 95% entre 175 et 250°C. Ce système permet donc une conversion des NOx élevée à basse température en s'affranchissant du NO2 procuré par le DOC. / The NOx Selective Catalytic Reduction is an efficient process for exhaust gas treatment. However, for Diesel vehicles, the activity at low temperature (175-250°C, starting phase of vehicles) remains limited. In addition, the NH3-SCR catalysts are sensitive to the NO2/NOx ratio, with an optimum for NO2/NOx = 0.5. Unfortunately, at low temperature, the proportion of NO2 is low because the oxidation catalyst (DOC) placed upstream is also weakly efficient.Ethanol (EtOH) is another possible reductant, mainly associated with Ag/Al2O3 catalysts. This system also has a limited activity at low temperature, although the oxidation of EtOH is accompanied by NO2 formation. In this work, the association of EtOH and NH3 for the SCR of NO on a Ag/Al2O3 catalyst was studied. A synergistic effect was obtained, with a high gain of conversion at low temperature. This gain neither results from a reaction between NH3 and EtOH or its oxidation by-products (CH3CHO, CO…), nor only by the reaction between NO2 (formed by reaction of NO with EtOH) and NH3. Characterization of adsorbed species by FTIR and (H2+NH3)-SCR experiments led to the conclusion that H* species, resulting from ethanol dehydrogenation, react with NOx to yield HNOx species highly reactive with NH3.Finally, in order to use the remaining NH3, NO and NO2, the use of a dual bed (2%Ag/Al2O3 + NH3-SCR catalyst) allowed a NOx conversion between 46 and 95% from 175 to 250°C. This system consequently allows a high NOx conversion at low temperature, avoiding the NO2 lack at low temperature (low DOC activity).

abstract: This dissertation presents research findings regarding the exploitation of localized surface plasmon (LSP) of epitaxial Ag islands as a means to enhance the photoluminescence (PL) of Germanium (Ge) quantum dots (QDs). The first step of this project was to investigate the growth of Ag islands on Si(100). Two distinct families of Ag islands have been observed. “Big islands” are clearly faceted and have basal dimensions in the few hundred nm to μm range with a variety of basal shapes. “Small islands” are not clearly faceted and have basal diameters in the 10s of nm range. Big islands form via a nucleation and growth mechanism, and small islands form via precipitation of Ag contained in a planar layer between the big islands that is thicker than the Stranski-Krastanov layer existing at room-temperature. The pseudodielectric functions of epitaxial Ag islands on Si(100) substrates were investigated with spectroscopic ellipsometry. Comparing the experimental pseudodielectric functions obtained for Si with and without Ag islands clearly identifies a plasmon mode with its dipole moment perpendicular to the surface. This observation is confirmed using a simulation based on the thin island film (TIF) theory. Another mode parallel to the surface may be identified by comparing the experimental pseudodielectric functions with the simulated ones from TIF theory. Additional results suggest that the LSP energy of Ag islands can be tuned from the ultra-violet to the infrared range by an amorphous Si (α-Si) cap layer. Heterostructures were grown that incorporated Ge QDs, an epitaxial Si cap layer and Ag islands grown atop the Si cap layer. Optimum growth conditions for distinct Ge dot ensembles and Si cap layers were obtained. The density of Ag islands grown on the Si cap layer depends on its thickness. Factors contributing to this effect may include the average strain and Ge concentration on the surface of the Si cap layer. The effects of the Ag LSP on the PL of Ge coherent domes were investigated for both α-Si capped and bare Ag islands. For samples with low-doped substrates, the LSPs reduce the Ge dot-related PL when the Si cap layer is below some critical thickness and have no effect on the PL when the Si cap layer is above the critical thickness. For samples grown on highly-doped wafers, the LSP of bare Ag islands enhanced the PL of Ge QDs by ~ 40%. / Dissertation/Thesis / Doctoral Dissertation Physics 2015

Made available in DSpace on 2014-12-17T15:18:12Z (GMT). No. of bitstreams: 1 LorenaCBL.pdf: 1131500 bytes, checksum: f844b916fb8784c601514bd7da1743b9 (MD5) Previous issue date: 2007-02-26 / The Tetraodontiformes order is composed for about 400 species of fish, distributed in ten families, with circuntropical distribution. The morphologic diversity of each family reflects in, part, the different levels of specialization. This group represents an ancestry after-Perciformes and constitutes the last branch of the diffusion of the Tele?steos, occupying a position of prominence. The phylogenetics relationships of the Tetraodontiformes exist diverse works examining and, in all, these families are recognized as groups brothers, being Diodontidae next to Tetraodontidae and Balistidae next to Monacanthidae. Although it possesss a representative number of species, the works involving of the families Balistidae and Monacanthidae are few exemplary, especially species of oceanic islands. In this work cytogenetic studies in five species had been analyzed Cantherhines macrocerus, Cantherhines pullus (Monacanthidae), Melichthys niger (Balistidae), Sphoeroides testud?neus (Tetraodontidae) and Chilomycterus antennatus (Diodontidae); through conventional coloration, Ag-NORs and C banding. Ahead of the different karyological trends of evolution presented by the Tetraodontiformes, the present work also searched to verify the relation existence enters the total size of the chromosomes with the amount of DNA in these groups of Tetraodontiformes. For such, they had been correlated the total size of the chromosomes of these species, with values of content of available DNA in literature. The cytogenetics analyses for the species C.macrocerusJ C.pullus (Monacanthidae) and M.niger (Balistidae), had disclosed 40 chromosomes, all acrocentrics. All possess only one pair of NORs and pericentromeric heterochromatin. For S.testud?neus the found dyploid number was equal 2n=46, with NF=78 (16m+18sm+8st+4a), while that for C.antennatus it possesss 2n=50, with NF=76 (4m+22st+24a). Both species possess simple NORs and pericentromeric heterochromatin blocks. In M.niger, the presence of positive marking (heterochromatin and NOR) in the secondary constriction in the second chromosomic pair suggesting the occurrence of a rearrangement, possibly a fusing involving these homologous ones, indicating that these events had been important for the establishment of the karyological history of this group. A maintenance of the chromosomic constancy found in the populations of C.macrocerus (Monacanthidae) and S.testudineus (Tetraodontidae) perhaps if must for the aiding of the gene flow through oceanic chains. These data contrast with the differentiated kinds of chromosomes of C.antennatus between the Northeast coast and Southeastern, suggesting that the ecological standards of each species, added to the conditions of the marine environment, can be responsible for the karyological delineation of each species. The found characteristics for the species C.macrocerus, C.pullus, M.niger, S.testudineus and C.antennatus add it the available data for other species of Tetraodontiformes. From the data gotten in the present study, it can be inferred that the DNA content possesss direct relation with the total length of the chromosomes / RESUMO A ordem Tetraodontiformes ? composta por cerca de 400 esp?cies de peixes, distribu?das em dez fam?lias, com distribui??o circuntropical. A diversidade morfol?gica de cada fam?lia reflete em, parte, os diferentes n?veis de especializa??o. Este grupo representa uma linhagem p?s-Perciformes e constitui o ?ltimo ramo da difus?o dos Tele?steos, ocupando uma posi??o filogen?tica de destaque. Nesta ordem encontram-se algumas das esp?cies de peixes mais conhecidas popularmente, os baiacus, fam?lias Diodontidae e Tetraodontidae; e os cangulos, fam?lias Balistidae e Monacanthidae. Existem diversos trabalhos examinando as rela??es filogen?ticas dos Tetraodontiformes e, em todos, estas fam?lias s?o reconhecidas como grupos irm?os, sendo Diodontidae mais pr?ximo de Tetraodontidae e Balistidae mais pr?ximo de Monacanthidae. Embora possua um n?mero representativo de esp?cies, s?o poucos os trabalhos citogen?ticos envolvendo exemplares das fam?lias Balistidae e Monacanthidae, especialmente esp?cies insulares. Neste trabalho foram analisadas citogeneticamente as esp?cies Cantherhines macrocerus, Cantherhines pullus (Monacanthidae), Melichthys niger (Balistidae), Sphoeroides testudineus (Tetraodontidae) e Chilomycterus antennatus (Diodontidae); atrav?s de colora??o convencional, Ag-RONs e bandamento C. Diante das diferentes tend?ncias de evolu??o cariot?picas apresentadas pelos Tetraodontiformes, o presente trabalho tamb?m buscou verificar a exist?ncia de rela??o entre o tamanho total dos cromossomos com a quantidade de DNA nestes grupos de Tetraodontiformes. Para tal, foram correlacionados o tamanho total do complemento hapl?ide destas esp?cies, com valores de conte?do de DNA dispon?veis na literatura. As an?lises citogen?ticas para as esp?cies C.macrocerus, C.pullus (Monacanthidae) e M.niger (Balistidae), revelaram um cari?tipo composto de 40 cromossomos, todos acroc?ntricos. Todas possuem apenas um par de RONs e heterocromatina pericentrom?rica. Para S.testudineus o n?mero dipl?ide encontrado foi igual a 2n=46, com NF=78 (16m+18sm+8st+4a), enquanto que para C.antennatus possui 2n=50, com NF=76 (4m+22st+24a). Ambas esp?cies possuem RONs simples e blocos heterocrom?ticos centrom?ricos. Em M. niger, a presen?a de marca??o positiva (heterocromatina e RON) na constri??o secund?ria no 2?par cromoss?mico em M. niger sugerindo a ocorr?ncia de um rearranjo, possivelmente uma fus?o envolvendo estes hom?logos, indicando que estes eventos foram importantes para o estabelecimento dos cari?tipos deste grupo.A manuten??o da const?ncia cariot?pica encontrada nas popula??es de C. macrocerus (Monacanthidae) e Sphoeroides testudineus (Tetraodontidae) talvez se deva pelo favorecimento do fluxo g?nico atrav?s das correntes oce?nicas. Estes dados contrastam com os cit?tipos diferenciados de C.antennatus entre a costa Nordeste e Sudeste, sugerindo que os padr?es ecol?gicos de cada esp?cie, somados ?s condi??es do meio ambiente marinho, possam ser respons?veis pela delinea??o cariot?opica de cada esp?cie. As caracter?sticas citogen?ticas encontradas para as esp?cies C.macrocerus, C.pullus, M.niger, S.testudineus e C.antennatus somam-se aos dados dispon?veis para outras esp?cies de Tetraodontiformes. A partir dos dados obtidos no presente estudo, pode-se inferir que o conte?do de DNA possui rela??o direta com o comprimento total do genoma

Die SME AG ist das erste Bergbauunternehmen, das seit Jahrzehnten ein neues Erzbergwerk erschließen und in Betrieb nehmen will. Traditionsreiche Bergbauunternehmen haben in der Vergangenheit neue Standorte, auf der Grundlage vorhandener Personalstrukturen, vorhandener Technik und Technologien, erschlossen. Im nachfolgenden Beitrag wird die strategische Herangehensweise der SME AG beschrieben, um zeitnah mit der Gewinnung in der Wolfram-Zinn-Lagerstätte zu beginnen.

Modern society’s industrial food system has led to several environmental problems and is compromising the fundamental aspects of agriculture such as fertile soil, biodiversity, and ecosystem services. In addition to this, the food system contributes to economic and social difficulties for actors within the agricultural sector. Hence, the food system requires a deep socio-economic change. Regionalwert AG is among other alternative food networks, an initiative to enhance sustainable agriculture by operating at a regional level. In this study, interviews were conducted with partner companies of Regionalwert AG with the aim to examine what motivates people to engage in alternative food networks, using Regionalwert AG as an exemplary case. A further aim was to examine the partnership between the partner companies and Regionalwert AG. The results were analysed using the study's state of knowledge and the theoretical framework, consisting of alienation theory. The study shows that the informants had unique stories about how they engaged with the network and that the partnership was constructed in three different ways: investment partnership, licensed partnership, and supportive partnership. The motivations that emerged from the study were divided into three themes: (i) economic, social and ideological, (ii) critical approach towards the food system, and (iii) re-connecting people with agriculture. The informants expressed that they want to spread knowledge and awareness about food production and Regionalwert AG makes this financially possible as well as provides a platform to spread the message about the value of food. / Det moderna samhällets industriella livsmedelssystem har lett till flera miljöproblem och det kompromissar fundamentala aspekter inom jordbruket som bördig jord, biodiversitet och ekosystemtjänster. Utöver miljöproblemen bidrar livsmedelssystemet till ekonomiska och sociala svårigheter för aktörer inom jordbrukssektorn. Därav krävs en stor socioekonomisk förändring av livsmedelssystemet. Regionalwert AG är tillsammans med andra alternativa livsmedelsnätverk ett initiativ till att öka hållbart jordbruk genom att verka på en regional nivå. I den här studien, genomfördes intervjuer med partnerföretag till Regionalwert AG med syftet att undersöka vad som motiverar människor att gå med i alternativa livsmedelsnätverk, genom att använda Regionalwert AG som ett exemplifierande fall. Ett ytterligare syfte var att undersöka partnerskapet mellan partnerföretagen och Regionalwert AG. Resultatet analyserades med hjälp av studiens kunskapsläge och teoretiska ramverk, bestående av alienationsteori. Studien visar att informanterna hade unika berättelser om hur de anslöt sig till nätverket och att partnerskapet var konstruerat på tre olika sätt: investerings partnerskap, licensierat partnerskap och stödjande partnerskap. Motivationerna som kom fram genom studien föll under tre teman: (i) ekonomisk, social och ideologisk, (ii) kritisk inställning mot livsmedelssystemet och (iii) återknyta människor med jordbruket. Informanterna uttryckte att de vill sprida kunskap och medvetenhet om matproduktion och Regionalwert AG gör detta finansiellt möjligt samt utgör en plattform för att sprida budskapet om värdet bakom livsmedel.

This diploma thesis summarizes knowledge from the fields of synthesis, characterization and application of titanium dioxide nanotubes and its combination with silver nanoparticles for biomedical purposes. Basic protocols of working with cell cultures and bacteria are also included. Experimental part of this diploma thesis focuses mainly on the synthesis of tubular structures made of titanium dioxide via anodic oxidation of 500nm titanium layer and their subsequent decoration with silver by electrodeposition. Last section of the experimental part is devoted to testing of antibacterial properties of the new material and examining the effect of different silver concentrations on the adhesion of MG-63 cells. All results are compared to reference samples consisting of titanium dioxide nanotubes without silver.

Die SME AG ist das erste Bergbauunternehmen, das seit Jahrzehnten ein neues Erzbergwerk erschließen und in Betrieb nehmen will. Traditionsreiche Bergbauunternehmen haben in der Vergangenheit neue Standorte, auf der Grundlage vorhandener Personalstrukturen, vorhandener Technik und Technologien, erschlossen. Im nachfolgenden Beitrag wird die strategische Herangehensweise der SME AG beschrieben, um zeitnah mit der Gewinnung in der Wolfram-Zinn-Lagerstätte zu beginnen.

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