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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

AN ANALYSIS INTO THE FUNCTIONING OF THE S. INTERMEDIUS B196 STREPTOCOCCUS INVASION LOCUS / THE STREPTOCOCCUS INVASION LOCUS IN S. INTERMEDIUS B196

Wu, Bryan January 2018 (has links)
The Streptococcus Anginosus Group (SAG) is a group of Gram-positive cocci which require carbon dioxide to grow. They are commensal members of the healthy upper respiratory, gastrointestinal and female urogenital tract; however, they are most commonly known as major pathogens in brain and liver abscesses, forming both mono- and polymicrobial infections. The Streptococcus invasion locus (sil), first identified as a virulence factor in Group A Streptococcus (GAS), has recently been identified in the SAG. The sil locus in GAS is a two component quorum-sensing system composed of three operons: silAB, coding for a two component system; silE/D/CR, coding for an ABC transporter and a signal peptide, and silC, which overlaps silCR on the opposite strand. The presence of exogenous SilCR activates SilA, which in turn upregulates the transcription of the silE/D/CR operon. In the SAG, however, silCR and silED have distinct promoters, and the SAG sil system lacks the silC gene. In this study, I examined the transcriptional dynamics of the sil system in S. intermedius B196. I determined that SilA is the major regulator of the genes in the sil system, being one of the first genes of the system to be expressed, and likely upregulates its own transcription. I also found evidence suggesting that, despite having its own promoter, silCR transcription may still be driven by the silED promoter. I also found evidence that suggests silED may be responsible for the export and/or processing of bacteriocins targeting closely related species or strains. / Thesis / Master of Science (MSc) / The Streptococcus are a group of bacteria known for causing diseases ranging from strep throat to flesh-eating disease; however, many species of Streptococcus are usually non-pathogenic, and live in our bodies without causing harm. One group of these bacteria, the Streptococcus Anginosus Group (SAG), is commonly found in our mouths and gut and usually cause no harm; however, in some cases it can cause infections. How these organisms switch from being nonpathogenic to pathogenic is unknown, but recently a gene network that appears to play a role in infection, the Streptococcus invasion locus (sil), was identified in the SAG. This gene network senses the signals released by other bacteria with the network, and only turns on when enough signal is present. The goal of this study is to examine how the system works in the SAG in order to determine how these bacteria coordinate sil gene expression.
2

Strategická analýza společnosti FABORY ? CZ, s. r. o.

Vojáčková, Alena Bc. January 2007 (has links)
Cílem práce je představit metody a nástroje používané při provádění strategické analýzy podnikatelského subjektu a tyto nástroje dále aplikovat na společnost FABORY ? CZ, s. r. o. V textu se objeví informace o následujících oblastech: analýza makrookolí společnosti (PEST a 4C analýza), analýza odvětví, analýza konkurenčního prostředí (Porterův model pěti sil), interní analýza firmy, SWOT analýza a další metody. V závěru textu jsou prezentovány konkrétní návrhy, které by měly zkoumané společnosti zajistit další růst a rozvoj.
3

Desenvolvimento do campo retrodifusor seletivo de alum?nio e boro em c?lulas solares de sil?cio / Development of the selective back surface field of aluminium and boron in silicon solar cells

Crestani, Thais 07 July 2016 (has links)
Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-10-06T11:11:45Z No. of bitstreams: 1 DIS_THAIS_CRESTANI_COMPLETO.pdf: 3613694 bytes, checksum: 40503ab7961f50b87d67545be969f402 (MD5) / Made available in DSpace on 2016-10-06T11:11:46Z (GMT). No. of bitstreams: 1 DIS_THAIS_CRESTANI_COMPLETO.pdf: 3613694 bytes, checksum: 40503ab7961f50b87d67545be969f402 (MD5) Previous issue date: 2016-07-07 / The typical solar cells of the industry are fabricated in p-type crystalline silicon wafers and have a pn junction at one side and, on the other side, the back surface field (BSF). The objective of this work is to develop solar cells with aluminum and boron selective back surface field to enable the passivation on the rear face with an industrial process. Czochralski p-type silicon wafers of solar grade quality were used. The boron diffusion was performed on the whole back side of the silicon wafers and the aluminum was screen-printed to form the selective back surface field under the metal grid. The boron diffusion temperature and time, the firing temperature of the metal pastes, the percentage of the rear area covered with aluminum and the passivation with SiO2 were evaluated in the electrical parameters. The best boron diffusion temperature was 970 ? C for 20 minutes and firing temperature of the metal pastes was 870 ? C. The solar cell with the highest efficiency were obtained for a rear metal grid with 14 % of the area covered by aluminum. The passivation by SiO2 on both surfaces increased the minority charge carrier diffusion length from 490 ?m to 665 ?m. Consequently, the passivation increased the efficiency from 15.6 % to 16.1 %, as a result of an increasing of the fill factor and the open circuit voltage. The passivation also increased the internal quantum efficiency in the range of violet/blue wavelengths as well as in the near infrared region. / As c?lulas solares t?picas da ind?stria s?o fabricadas em sil?cio cristalino tipo p e possuem uma jun??o pn em uma das faces, e na outra face, ? formado o campo retrodifusor. O objetivo deste trabalho foi desenvolver c?lulas solares com o campo retrodifusor seletivo de alum?nio e boro para possibilitar a passiva??o na face posterior, com processo industrial. Foram utilizadas l?minas de sil?cio Czochralski tipo p, grau solar. A difus?o de boro foi realizada em toda a face posterior da l?mina de sil?cio e por serigrafia foi depositada a pasta de alum?nio para formar o campo retrodifusor seletivo nas trilhas met?licas. Avaliou-se influ?ncia da temperatura e do tempo de difus?o de boro, a temperatura de queima das pastas met?licas, o percentual da ?rea posterior recoberta por alum?nio e a passiva??o com SiO2 nos par?metros el?tricos. A melhor temperatura de difus?o de boro foi de 970 ?C durante 20 minutos e a temperatura de queima das pastas met?licas foi de 870 ?C. A c?lula com maior efici?ncia foi obtida com a malha posterior com ?rea de recobrimento de alum?nio de 14%. A passiva??o com SiO2 em ambas as superf?cies aumentou a efici?ncia e o comprimento de difus?o dos portadores de carga minorit?ria aumentou de 490 ?m para 665 ?m. Com a passiva??o, a efici?ncia aumentou de 15,6 % para 16,1 %, devido ao aumento do fator de forma e da tens?o de circuito aberto. A passiva??o tamb?m aumentou a efici?ncia qu?ntica interna no intervalo de comprimento de onda do violeta/azul bem como na regi?o do infravermelho pr?ximo.
4

Modellering och simulering av hydraulik för användning i hardware-in-the-loop / Modeling and simulation of hydraulics for use in hardware-in-the-loop

Israelsson, Erik January 2012 (has links)
Modeling and simulation is growing ever more important in the development of new products. This thesis describes the use of Hopsan for hydraulic modeling and its use in conjunction with Simulink with the intent of using the model in a hardware-in-the-loop setup. A sensor layer has been created in Simulink to emulate all the internal sensors in a modern forklift. The details of using legacy C-code instead of a hardware MCU for a fully simulated environment, software-in-the-loop has been outlined. There are two major routes one can follow implementing software-in-the-loop, exporting the C-functions to CAPL via a export layer or creating an s-function in Simulink. Of the two the export layer method is the most promising since it is easier handling different execution times in CAPL than in Simulink.
5

Analýza odvětví stavebnictví v ČR

Kubínová, Martina January 2009 (has links)
No description available.
6

Optimalizace pracovních sil / Workforce Optimisation

Pacinda, Štefan January 2011 (has links)
Title: Workforce Optimisation Author: Štefan Pacinda Department / Institute: Department of Theoretical Computer Science and Mathematical Logic (KTIML) Supervisor of the master thesis: doc. RNDr. Roman Barták Ph.D., KTIML Abstract: Workforce management deals with the problem of maintaining productive workforce for example in call centers, hospitals, transportation companies etc. It includes the problem of deciding which skills are necessarily at each given time and how many personnel with given skills is required. These decisions are followed by solving the problem of allocating particular employees to shifts while satisfying the skill demands but also other constraints derived for example from law regulations, trade unions agreements, and individual preferences. This thesis deals with workforce optimization, that is with the optimal assignment of personnel to shifts in order to cover the demand for resources that vary over time. In this paper the solved problem is described in all detail and modeled as mixed integer program. Implementation details are presented and exhaustive analysis and experiments on a real life problem instance are performed to assure that the aims of the work have been met. Keywords: Rostering, Workforce Management, Shift Scheduling
7

Otimiza??o e desenvolvimento de c?lulas solares industriais em substratos de sil?cio multicristalino

Wehr, Gabriela 07 May 2008 (has links)
Made available in DSpace on 2015-04-14T13:58:27Z (GMT). No. of bitstreams: 1 401486.pdf: 2235919 bytes, checksum: 4ff678b49860d16d47ec2e0ccbb3f5b6 (MD5) Previous issue date: 2008-05-07 / O crescimento exponencial do mercado de dispositivos fotovoltaicos e a necessidade de substratos de menor custo tornam o sil?cio multicristalino uma importante op??o para a fabrica??o de c?lulas solares. Esta disserta??o tem como objetivo otimizar e desenvolver as principais etapas de um processo para fabrica??o de c?lulas solares em substrato de sil?cio multicristalino, com a estrutura n+pn+ e 36 cm2 de ?rea. Foram otimizadas, por meio de simula??es, as regi?es dopadas e as malhas de metaliza??o e, experimentalmente, o emissor e as condi??es de queima das pastas met?licas no processo de metaliza??o por serigrafia. De acordo com os resultados obtidos da otimiza??o por simula??es, ? poss?vel obter c?lulas solares com 16,2 % de efici?ncia para altos valores de tempo de vida dos portadores minorit?rios de 100 μs e com regi?o de campo retrodifusor. As efici?ncias de 15,8 %, 14,6 % e 12,1 % podem ser obtidas para o tempo de vida dos minorit?rios de 50 μs, 10 μs e 1 μs, respectivamente, quando a metaliza??o for por serigrafia com malha met?lica com trilhas de 100 μm de largura. Constatou-se que a efici?ncia ? menor, da ordem de 0,3 % a 0,5 %, quando a largura das trilhas da malha de metaliza??o ? aumentada de 100 μm para 200 μm. Tamb?m se verificou que quanto maior a largura das trilhas, maior a profundidade da jun??o e da regi?o do campo retrodifusor para a mesma concentra??o em superf?cie. No processo para a otimiza??o experimental do emissor, obtiveram-se os valores de resist?ncia de folha em fun??o da temperatura da difus?o. A temperatura e o tempo com os quais se obt?m a resist?ncia de folha de 50 Ω/□, selecionada para a fabrica??o de c?lulas solares com metaliza??o por serigrafia, ? de 820?C e 30 minutos. Da an?lise das c?lulas solares fabricadas constatou-se que a temperatura de queima das pastas afeta o desempenho das c?lulas solares, enquanto que a velocidade da esteira praticamente n?o influencia nos par?metros el?tricos das mesmas. As maiores efici?ncias foram encontradas para a temperatura de queima entre 860 ?C e 880 ?C. 16 Tamb?m se verificou que a espessura do filme anti-reflexo influencia o fator de forma e a corrente el?trica das c?lulas solares. A maior efici?ncia alcan?ada foi de 11,5 %, com fator de forma de 0,74, para a temperatura de queima da pasta de 860 ?C, velocidade da esteira de 190 cm/min e dupla camada anti-reflexo de Si3N4 e TiO2.
8

Influ?ncia do ataque anisotr?pico e do processo de queima de pastas met?licas em c?lulas solares industriais

Ly, Moussa 28 June 2011 (has links)
Made available in DSpace on 2015-04-14T13:58:44Z (GMT). No. of bitstreams: 1 434556.pdf: 1369683 bytes, checksum: f99358643c6291a4c1fd0bae8edb9536 (MD5) Previous issue date: 2011-06-28 / O objetivo desta tese ? analisar a influ?ncia do ataque anisotr?pico e do processo de queima de pastas met?licas em c?lulas solares industriais. Para implementar a malha met?lica em c?lulas solares por serigrafia ? realizado um passo t?rmico de queima de pastas met?licas. Durante este processo, a pasta de prata deve perfurar o filme antirreflexo para estabelecer o contato el?trico com a l?mina de sil?cio. Por?m, este processo pode alterar as propriedades do filme antirreflexo e as caracter?sticas el?tricas das c?lulas solares. Para analisar o efeito deste passo t?rmico nos filmes antirreflexo, depositaram-se, por evapora??o em alto v?cuo com canh?o de el?trons, TiO2, Ta2O5 e Si3N4 sobre as l?minas de sil?cio texturadas, com e sem camada passivadora de SiO2 de 10 nm. As espessuras dos filmes foram definidas considerando a reflex?o m?nima em 550 nm e variaram-se a temperatura e velocidade da esteira do forno usado na queima de pastas. Observou-se que a reflet?ncia m?dia aumentou de 0,5% a 1,5% para os filmes de TiO2 e Ta2O5 e de 1,0% a 2,3% para o filme de Si3N4, deslocando a reflet?ncia m?nima para comprimentos de ondas menores. Concluiu-se que devem ser depositados filmes de maior espessura para compensar estas mudan?as na reflet?ncia. Em rela??o ao processo para forma??o de micropir?mides nas superf?cies, o processo foi otimizado usando a reflet?ncia m?dia como par?metro. Para verificar a influ?ncia da espessura do filme de TiO2 nas caracter?sticas el?tricas de c?lulas solares, foram fabricados dispositivos com estrutura n+pn+.
9

An?lise de filmes antirreflexo de di?xido de tit?nio e nitreto de sil?cio em c?lulas solares P+NN+

Fagundes, Raquel Sanguin? 07 December 2012 (has links)
Made available in DSpace on 2015-04-14T13:58:55Z (GMT). No. of bitstreams: 1 444962.pdf: 1192335 bytes, checksum: 99f2c1e4c50a70affaa97a11bf6d814e (MD5) Previous issue date: 2012-12-07 / In this work we compared the antireflection coatings of titanium dioxide and silicon nitride for p+nn+ solar cell fabrication. This type of solar cell is more stable in the long term compared to n+pp+ cells and allows obtaining higher efficiencies. TiO2 films were produced by evaporation in high vacuum by electron beam and by chemical vapor deposition at atmospheric pressure (APCVD). The silicon nitride antireflection layer was obtained by reactive sputtering and by plasma enhanced chemical vapor deposition (PECVD). The films were deposited on textured silicon wafers and were characterized by measuring the spectral reflectance. Solar cells with these films were fabricated and characterized. The deposited films presented very low weighted reflectance, of around 1.8 % for silicon nitride films and 2.6 % for titanium dioxide ones, for any technique used. The lowest average weighted reflectance was obtained with SiNx:H thin films deposited by PECVD, with (1.93 ? 0.08) %. Concerning the homogeneity of the films, silicon nitride films presented the lowest standard deviation in the average weighted reflectance, of around 4 % relative. A thermal process performed at 840 ?C in a belt furnace modifies the average weighted reflectance of about 0.3 % to 0.6 % absolutes for silicon nitride and TiO2 films, respectively. The p+nn+ solar cells doped with boron and phosphorus and metallized by screen printing reached the highest efficiencies where manufactured by using silicon nitride antireflection coating deposited by PECVD. The maximum efficiency of 13.7 % and an average of (13.5 ? 0.2) %, were achievied mainly because they showed a short circuit current density of around 1 mA/cm2 above that from solar cells with the other films investigated in this work. This difference is attributed not only to a low reflectance but also to a better surface passivation of SiNx:H layer. / Neste trabalho foram comparados os filmes antirreflexo de di?xido de tit?nio e de nitreto de sil?cio para fabrica??o de c?lulas solares p+nn+. Este tipo de c?lula solar ? mais est?vel em longo prazo em rela??o ?s c?lulas n+pp+ e permite a obten??o de maiores efici?ncias. Os filmes de TiO2 foram produzidos por evapora??o em alto v?cuo com canh?o de el?trons e por deposi??o qu?mica em fase vapor a press?o atmosf?rica (APCVD). A camada antirreflexo de nitreto de sil?cio foi obtida por sputtering reativo e por deposi??o qu?mica em fase vapor assistida por plasma (PECVD). Os filmes foram depositados em l?minas de sil?cio texturadas e caracterizados pela medida da reflet?ncia espectral bem como foram fabricadas e caracterizadas c?lulas solares com os filmes. Os filmes depositados apresentaram reflet?ncia m?dia ponderada bastante baixas, da ordem de 1,8 % para filmes de nitreto de sil?cio e de 2,6 % para filmes de ?xido de tit?nio, n?o interessando a t?cnica utilizada. A menor m?dia de reflet?ncia ponderada foi obtida com os filmes de SiNx:H depositados por PECVD, com (1,93 ? 0,08) %. No que se refere a homogeneidade dos filmes, os filmes de nitreto de sil?cio foram os que apresentaram o menor desvio padr?o nas m?dias de reflet?ncia ponderada, da ordem de 4 % relativo. Observou-se que um processo t?rmico realizado a 840 ?C em forno de esteira provocou varia??es na reflet?ncia m?dia ponderada da ordem de 0,3 % a 0,6 % absoluto para filmes de nitreto de sil?cio e de TiO2, respectivamente. As c?lulas solares p+nn+, dopadas com boro e f?sforo e metalizadas por serigrafia que atingiram as maiores efici?ncias foram as fabricadas com nitreto de sil?cio depositado por PECVD, atingindo a efici?ncia m?xima de 13,7 % e m?dia de (13,5 ? 0,2) %, principalmente porque apresentaram uma densidade de corrente de curtocircuito da ordem de 1 mA/cm2 superior a de c?lulas solares com os demais filmes estudados nesta disserta??o. Esta diferen?a foi atribu?da n?o somente a uma menor reflet?ncia mas tamb?m a passiva??o de superf?cie mais eficaz do filme de SiNx:H.
10

C?lulas solares com campo retrodifusor seletivo : passiva??o frontal e posterior com nitreto de sil?cio / Solar cells with back surface field : front and read passivation with silicon nitride

Aquino, J?ssica de 24 January 2017 (has links)
Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-04-07T18:03:32Z No. of bitstreams: 1 DIS_JESSICA_DE_AQUINO_COMPLETO.pdf: 2934640 bytes, checksum: 153da3d44efdfe566dcf3c4a87da1eac (MD5) / Made available in DSpace on 2017-04-07T18:03:32Z (GMT). No. of bitstreams: 1 DIS_JESSICA_DE_AQUINO_COMPLETO.pdf: 2934640 bytes, checksum: 153da3d44efdfe566dcf3c4a87da1eac (MD5) Previous issue date: 2017-01-24 / The majority of silicon solar cells manufactured in an industrial scale is processed in Si-Cz p-type substrates and has the n+pp+ structure. In the last decade, the search for efficiency improvements and fabrication cost reductions has been intensified. Since the cell efficiency is limited by optical losses and surface recombination, the rear and front surface passivation is an alternative for the enhancement of the efficiency. The goal of this dissertation is to develop and analyze solar cells with selective back surface field of boron and aluminum and silicon nitride thin films for the passivation of both surfaces. The silicon nitride thin films were deposited by PECVD (plasma-enhanced chemical vapor deposition), with ratios of silane to ammonia gas flow of 0.875, 1.5 and 2.0, and deposition time of 60 to 100 seconds, adjusted to form the anti-reflection coating. The thickness of the SiNx films, minority carrier lifetime, electrical parameters, minority carrier diffusion length and quantum efficiency were analyzed and compared. The results indicate that the lower the ratio between the silane and ammonia gas flows and the shorter the deposition time, the higher the efficiency of the solar cells manufactured. Due to the passivation, mainly in the front face, caused by the silicon nitride film deposited with the lower ratio of silane and ammonia gas flow and lower deposition time, we observed an increasing oh the internal quantum efficiency, mainly in shorter wavelength. The efficiency reached was 16.0 %, similar to the efficiency of solar cells with aluminium homogeneous back surface field. / A maioria das c?lulas solares de sil?cio fabricadas em escala industrial ? processada em substratos de Si-Cz tipo p e possuem estrutura n+pp+. Na ?ltima d?cada, intensificou-se a busca por melhores efici?ncias e redu??o dos custos de fabrica??o. Como as c?lulas s?o limitadas pelas perdas ?pticas e pela recombina??o nas superf?cies, a passiva??o da superf?cie posterior, al?m da superf?cie frontal, ? uma alternativa para aumentar a efici?ncia dos dispositivos. O objetivo dessa disserta??o ? desenvolver e avaliar c?lulas solares com campo retrodifusor seletivo de boro e alum?nio e passivadas com filme fino de nitreto de sil?cio em ambas as faces. Os filmes de nitreto de sil?cio foram depositados por PECVD (plasmaenhanced chemical vapor deposition) com a raz?o da vaz?o dos gases silano e am?nia de 0,875, 1,5 e 2,0 e tempos de deposi??o de 60 a 100 segundos, ajustados para formar o filme antirreflexo. Analisaram-se e compararam-se a espessura do filme, o tempo de vida dos portadores de carga minorit?rios, os par?metros el?tricos, o comprimento de difus?o e a efici?ncia qu?ntica. Os resultados indicaram que quanto menor a raz?o entre o fluxo dos gases silano e am?nia e menor tempo de deposi??o, maior a efici?ncia das c?lulas solares fabricadas. Devido a maior passiva??o, principalmente na face frontal provocada pelo filme de nitreto de sil?cio depositado com a menor raz?o da vaz?o dos gases silano e am?nia e menor tempo de deposi??o, observou-se um aumento da efici?ncia qu?ntica interna, principalmente para menores comprimentos de onda e alcan?ou-se a efici?ncia de 16,0 %, similar ? efici?ncia das c?lulas solares com emissor homog?neo de alum?nio.

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