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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.
81

Superfícies super-hidrofóbicas obtidas através de microestruturas litografadas. / Superhydrophobic surfaces obtained by microstructures lithographed.

Oliveira, Márcio Roberto da Silva 07 October 2011 (has links)
Aqui apresentamos um modelo teórico para superfícies super-hidrofóbicas que são formadas por superfícies contendo padrões periódicos na forma de microcavidades. Com este modelo obtivemos a relação ideal entre profundidade e diâmetro das cavidades para que a superfície manifeste seu caráter super-hidrofóbico. Assim, fabricamos superfícies em PDMS (popular silicone) capazes de produzir ângulos de contato elevados. Produzimos amostras contendo microcavidades específicas (paralelepípedas, hexagonais e cilíndricas) as quais foram microfabricadas por litografia de feixes de elétrons e caracterizadas por Microscopia Eletrônica de Varredura (MEV), Microscopia de Força Atômica (AFM), e medidas de ângulo de contato. Os padrões das microcavidades das superfícies produzidas seguiram as considerações da teoria e as medidas dos ângulos de contato de avanço e recesso mostram boa concordância com as previsões do modelo. Portanto, podemos afirmar que a teoria aqui descrita permite projetar superfícies altamente hidrofóbicas. / Here we present a theoretical model for super-hydrophobic surfaces formed by surfaces containing periodic patterns in the form of microcavities. With this model we obtained the ideal relationship between depth and diameter of the cavities so that the surface expresses a super-hydrophobic character. Thus manufacture of PDMS surfaces (with known silicone) is capable of producing high contact angles. We produced samples containing specific microcavities (parallelepipeds, hexagonal and cylindrical) which have been microfabricated by electron beam lithography and characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements. The patterns of the surfaces of the cavities produced following the considerations of theory and measurements of advancing and recending contact angles show good agreement with the model predictions. Therefore, we can attest that the theory described here allows the design of highly hydrophobic surfaces.
82

秘密社會之動員: 1796-1805年白蓮敎運動之個案硏究. / Mi mi she hui zhi dong yuan: 1796-1805 nian Bailian jiao yun dong zhi ge an yan jiu.

January 1991 (has links)
朱耀光. / Thesis (M.A.)--香港中文大學, 1991. / Manuscript (computer printout). / Includes bibliographical references (leaves 152-163). / Zhu Yaoguang. / Thesis (M.A.)--Xianggang Zhong wen da xue, 1991. / 序言 --- p.i / 撮要 --- p.iv / Chapter 第一篇 --- 十九世紀中國:一個巨型的社會現象 / Chapter 第一章 --- 導論 --- p.1 / Chapter 第二章 --- 秘密社會之定義及類型 --- p.4 / Chapter 第三章 --- 十九世紀中國秘密社會運動 --- p.11 / Chapter 第二篇 --- 研究秘密社會運動之方法與理論 / Chapter 第四章 --- 研究方法 --- p.16 / Chapter 一. --- 資料來源 / Chapter 二. --- 個案分析 / Chapter 第五章 --- 社會運動之理論 --- p.21 / Chapter 一. --- 宏觀角度:運動之興起 / Chapter 1. --- 滿漢矛盾理論 / Chapter 2. --- 階级鬥爭理論 / Chapter 3. --- 政治效率理論 / Chapter 4. --- 救贖信仰理論 / Chapter 二. --- 微觀角度:個人之參與 / Chapter 1. --- 政治動機理論 / Chapter 2. --- 本土政治理論 / Chapter 三. --- 資源動員之分析架構 / Chapter 第三篇 --- 中國秘密社會之動員:白蓮教運動之個案硏究 / Chapter 第六章 --- 十九世紀中國秘密社會之動員模式 --- p.48 / Chapter 一. --- 结構性資源之分配模式 / Chapter 二. --- 秘密社會之組織性資源 / Chapter 三. --- 秘密社會之催發性資源 / Chapter 第七章 --- 白蓮教運動之歴史背景 --- p.73 / Chapter 一. --- 發展源流 / Chapter 二. --- 意識形態 / Chapter 三. --- 組織結構 / Chapter 第八章 --- 1796´ؤ1805年白蓮教運動之個案分析 --- p.79 / Chapter 一. --- 資源動員之過程 / Chapter 1. --- 運動的冒起:資源之累積 / Chapter 2. --- 運動的擴張:資源之競爭 / Chapter 3. --- 運動的回落:資源之轉化 / Chapter 4. --- 運動的沉寂:資源之喪失 / Chapter 二. --- 社會後果之分析 / Chapter 1. --- 資源管理模式之調整 / Chapter 2. --- 資源分配模式之調整 / Chapter 三. --- 小結 / Chapter 第九章 --- 總結 --- p.139 / Chapter 一. --- 研究成果之撮要 / Chapter 二. --- 硏究成果之反思 / 注釋 --- p.149 / 參考書目 --- p.163
83

Melhoramento genético de Lotus corniculatus visando tolerância à toxidez por alumínio / Lotus corniculatus breeding for tolerance to aluminum toxicity

Santos, Armando Martins dos January 2009 (has links)
Solos ácidos com toxidez por Al são comuns, sendo geralmente destinados à pecuária. A utilização de leguminosas forrageiras adaptadas a esta situação minimizaria o uso de correção de acidez e ainda possibilitaria um aporte de N ao sistema via fixação biológica. A caracterização e a identificação de mecanismos de tolerância ao Al tóxico são os passos iniciais em um programa de seleção e melhoramento visando maior adaptação a esta condição de estresse. Este trabalho objetivou: (i) caracterizar genótipos de cornichão (L. corniculatus), espécies diplóides, inclusive da espécie modelo L. japonicus e linhas endogâmicas recombinantes (LER) de Lotus, quanto à tolerância ao Al tóxico; (ii) identificar o acúmulo de Al e exsudação radicular de ácidos orgânicos nas espécies cultivadas; e (iii) selecionar genótipos com respostas contrastantes ao Al tóxico, comparando-os através de caracteristicas agronômicas e moleculares. Os resultados da caracterização mostraram que as espécies modelo diplóides MG-20 e GIFU, a população UFRGS, e as cvs. San Gabriel e São Gabriel foram as mais produtivas de maneira geral. A população UFRGS apresentou ainda uma grande superioridade em situações de moderada acidez do solo (22,2% de Al), demonstrando um potencial de utilização em regiões onde se realize correção parcial do solo. Das 180 LERs testadas, 24 foram superiores e 39 foram inferiores a espécie modelo GIFU. Com relação à exsudação radicular de ácidos orgânicos, na ausência de Al observaram-se baixos níveis de exudação para todos os genótipos. Já na presença do Al, os resultados mostraram que o genótipo UFRGS, selecionado para tolerância ao Al (UF-T2), apresentou aumento significativo (pelo menos 50% superior) da exudação de ácido oxálico em relação aos demais genótipos, assim como a população UFRGS mostrou-se superior à cv. Draco em todas as avaliações. O resultado de dois ciclos de seleção massal visando tolerância ao Al mostrou incrementos na produção de matéria seca em todas as concentrações de Al testadas, enquanto que a seleção para sensibilidade ao Al pareceu estar relacionada com o baixo vigor das plantas, uma vez que na ausência de Al estes genótipos apresentaram menor acúmulo de matéria seca em relação às populações originais. A grande diversidade observada nos genótipos avaliados pode indicar que mecanismos de tolerância ao Al possam atuar em diferentes intensidades. A exudação de ácido oxálico parece ser um mecanismo que permite a manutenção do crescimento do cornichão em condições de Al tóxico, sendo que a seleção de um genótipo mais tolerante ao Al proporcionou aumentos significativos neste mecanismo de defesa. / Acid soils with aluminum (Al) toxicity are common, being generally destined for cattle livestock. The utilization of forage legumes adapted to this situation would minimize the use of agricultural liming materials and still allow a nitrogen input to the system via biological fixation. The characterization and identification of tolerance mechanisms to toxic Al are the initial steps in a selection and breeding program aiming a greater adaptation to this stress condition. This work was aimed to: (i) characterize cultivated populations of birdsfoot trefoil (tetraploid), model species (diploid) and recombinant inbred lines (RIL) of Lotus, regarding toxic Al tolerance; (ii) identify the accumulation of Al and root exudation of organic acids in the cultivated species; and (iii) select genotypes with contrasting responses to the toxic Al, comparing their morphological and molecular characteristics. The results of the characterization showed that the diploid genotypes, MG-20 and GIFU, and the cultivated UFRGS genotypes, San Gabriel and São Gabriel were the most productive in a general matter. The UFRGS genotype also presented a great superiority in situations of moderate soil acidity (22,2% of Al), demonstrating a utilization potential in regions where partial soil amelioration is done. Of the180 RILs tested, 24 were superior and 39 were inferior to the GIFU genotype. Regarding root exudation of organic acids, in the absence of aluminum, low levels of exudation were observed for all genotypes. However, in the presence of aluminum, the results showed that the UFRGS genotype selected for Al tolerance presented a significant increase (at least 50% higher) of oxalic acid exudation compared to the other genotypes, and the UFRGS genotype proved superior to the Draco genotype in all evaluations. The result of two mass selection cycles aiming Al tolerance showed increments in dry matter production in all of the toxic aluminum concentrations tested, while the selection for Al sensibility seemed to be related to the plants’ low vigor, since in the absence of Al these genotypes presented a lower accumulation of dry matter compared to the original populations. The great diversity observed in the evaluated genotypes may indicate that the Al tolerance mechanisms may act in different intensities. The exudation of oxalic acid is apparently a mechanism that permits the maintenance of the birdsfoot trefoil growth in different conditions of toxic Al, as well as the selection of a more tolerant genotype to aluminum permitted a significant increase in this defense mechanism.
84

A Comparison Between Self-Cleaning Properties via Rolling Droplets and Condensation on Superhyrophobic Surfaces

Miller, David Leland 01 December 2017 (has links)
Superhydrophobic (SH) surfaces are super water repellent surfaces on which a droplet of water will bead up like a marble and roll off the surface with minimal tilting of the surface. This is caused by the combination of a hydrophobic coating and a rough surface structure. To achieve thermodynamic stability, surface tension of the water pulls the droplet into this shape to minimize the contact area between the droplet and the surface. This creates a high contact angle (CA) between the droplet and the surface and a low sliding angle (SA) of which the droplet begins to roll off the surface. SH surfaces have a variety of potential applications such as drag reduction, anti-icing, improved heat transfer through condensation, and self-cleaning. Numerous reports have been dedicated to exploring the fluid dynamic behavior of water droplets on SH surfaces. This thesis focuses on exploring the self-cleaning properties of SH surfaces. Surfaces contaminated with salt, tobacco, and pollen are cleaned by rolling water droplets over the surface or condensing water on the surface such that when large enough, these droplets roll away due to gravity. SH surfaces explored here are composed of micro-scale or nano-scale rib and cavity structures and are compared with smooth, hydrophobic surfaces with a similar hydrophobic coating. To determine the self-cleaning efficiency of each surface, the CA and SA were measured before and after each surface was cleaned. In this study, it was observed that the presence of each of the three contaminates considered greatly affects the overall hydrophobicity of the surface, as indicated by the CA and SA. Ideally, as the contaminates are removed from the surface, the hydrophobicity of the surface improves to match the hydrophobicity of a clean surface. This is best seen on surfaces contaminated with salt as the CA and SA match that of a clean surface after only two to three water droplets roll over the surface or after the first condensed water droplets roll off the surface. This implies that all the salt particles are removed from the SH surface. Surfaces contaminated with tobacco showed that the hydrophobicity improves to a limited extent when cleaned with rolling water droplets or condensation but never is capable of matching the hydrophobicity of a clean surface. This suggests that only a portion of the tobacco residue is capable of being removed from the surface by either of the two cleaning methods considered in this thesis. Finally, when water came in contact with pollen on the surfaces, it experienced hydrodynamic osmosis leading to cellular bursting. After cellular bursting, the surface behaves as a hydrophilic surface and selfcleaning properties were never observed on any surface contaminated with pollen. Thus, overall this study shows that rolling water droplets over a contaminated surface and condensing water droplets on a contaminated surface are both viable means of utilizing the self-cleaning properties on SH surfaces. For the contaminates considered in this study, the efficiency of the self-cleaning surfaces is shown to be the same for both micro-structured and nano-structured surfaces.
85

Dokumenthanteringssystem inom byggbranschen / Document handling system within the building trade

Olovsson, Nils-Göran January 2003 (has links)
<p>One of the aims of this report has been to make an inventory of the building trade market to see which document handling systems that are available. The secondary aim was to document the users´ demands on the systems and other demands such as quality assurance. After this, the document handling systems Byggnet and Lotus Notes, which are rather complex systems, have been analysed. Finally a recommendation has been made. </p><p>In the inventory of the marketthe internet has been used because it is there the latest information can be found. This because document handling systems are rather new and there are therefore no other literature written yet. To get the users´ demands on the systems several interviews have been made. </p><p>The result of the inventory is that there are six different document handling systems available today. And the recommendation is that Byggnet is an appropriate system to use.</p>
86

Lotus Firefly : The art of defeating gravity

Ciobanu, Alexandra January 2013 (has links)
How many times have you been dreaming as a child that you run and after a few steps your body detaches off the ground and floats into the air? Most of the leisure activities we cultivate today have deep roots into humankind`s history and are still confined to land. The history of hovering has been inspired by the great comic books sci-fi stories and was illustrated through Star Wars flying vehicles, which have been later translated into jetpacks and hovering bikes. What if you would be stuck somewhere in the middle way between dream and reality? What if this vehicle would be at first available to you in a virtual platform, so that you could train to fly it, and when you would master the art or flying it, you could try the real experience?
87

Dokumenthanteringssystem inom byggbranschen / Document handling system within the building trade

Olovsson, Nils-Göran January 2003 (has links)
One of the aims of this report has been to make an inventory of the building trade market to see which document handling systems that are available. The secondary aim was to document the users´ demands on the systems and other demands such as quality assurance. After this, the document handling systems Byggnet and Lotus Notes, which are rather complex systems, have been analysed. Finally a recommendation has been made. In the inventory of the marketthe internet has been used because it is there the latest information can be found. This because document handling systems are rather new and there are therefore no other literature written yet. To get the users´ demands on the systems several interviews have been made. The result of the inventory is that there are six different document handling systems available today. And the recommendation is that Byggnet is an appropriate system to use.
88

Development of database support for production of doubled haploids

Engerberg, Malin January 2002 (has links)
<p>In this project relational and Lotus Notes database technology are evaluated with regard to their suitability in providing computer-based support in plant breeding in general and specifically in the production of doubled haploids. The two developed databases are compared based on a set of requirements produced together with the DH-group which is the main users of the databases. The results indicate that both Lotus Notes and the relational databases are able to fulfil all needs documented in this project, although both systems have their limitations. An often expressed opinion is that it is difficult to combine biology and databases. The experience gained in this project however suggests that it does not need to be the case in instances where data is not as complicated as often discussed. Observations made during this project indicate that data warehousing with integrated data mining and OLAP tools are surprisingly similar to how the DH-group at Svalöf Weibull works and could be a suitable solution for the production of doubled haploids.</p>
89

Įmonių administravimo ir dokumentų valdymo sistemos internete / Document management and enterprise administration system on the Internet

Jankūnas, Laimonas 28 May 2004 (has links)
This article examines the Internet software design technology using Lotus Notes. Current method is based on architecture decomposition in to separate program logics, data, user interface and graphics layers. The practical value of these methods is revealed – increased performance and product support simplicity.
90

Respiratory adaptations of secondarily aquatic organisms : studies on diving insects and sacred lotus

Matthews, Philip Gordon Douglas. January 2007 (has links)
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, Discipline of Ecological and Evolutionary Biology, 2008. / "December 2007" Bibliography: leaves 117-123. Also available in print form.

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