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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.
21

A first principles study of the thermodynamics of phase separating systems -The examples RhPd and AlZn-

Johansson, Jimmy January 2009 (has links)
A screened GPM approach in an EMTO-CPA framework was investigated in order to study its ability of describing transition temperatures in phase separating systems, i. e. systems giving either a random or a cluster structure depending on the temperature and the relative concentration of the ingoing atoms of the binary alloy used for the study. A motivation for the study is that the method works well for ordering systems, i. e. systems giving either a random or ordered structure dependent on the temperature and the relative concentration of the components in the binary alloy. Thereby is it of interest to find out the methods capacity in phase separating systems. The so called GPM potentials derived in the approach were applied in statistical Monte Carlo simulations for this purpose. The systems chosen for the investigation were the RhPd and the AlZn binary alloy systems. For both systems the method showed acceptable accuracy when properties as lattice parameter and mixing enthalpy were calculated. The quality of the derived GPM potentials has also been checked by calculating ordering energy for different ordered structures; directly from first principles calculations and from the GPM approach. The results were in acceptable agreement and thereby indicating that the GPM potentials were reliable. The transition temperatures in the RhPd phase diagram, derived by the statistical Monte Carlo simulations showed anyway deviation from experimental results. The error in the predictions might be due to the existing concentration dependencies in the GPM potentials.The conclusion from this study is that the Monte Carlo scheme might be inconvenient in order to handle the concentration dependencies seen in the GPM potentials.
22

Hash Families and Cover-Free Families with Cryptographic Applications

Zaverucha, Gregory 22 September 2010 (has links)
This thesis is focused on hash families and cover-free families and their application to problems in cryptography. We present new necessary conditions for generalized separating hash families, and provide new explicit constructions. We then consider three cryptographic applications of hash families and cover-free families. We provide a stronger de nition of anonymity in the context of shared symmetric key primitives and give a new scheme with improved anonymity properties. Second, we observe that nding the invalid signatures in a set of digital signatures that fails batch veri cation is a group testing problem, then apply and compare many group testing algorithms to solve this problem e ciently. In particular, we apply group testing algorithms based on cover-free families. Finally, we construct a one-time signature scheme based on cover-free families with short signatures.
23

Hash Families and Cover-Free Families with Cryptographic Applications

Zaverucha, Gregory 22 September 2010 (has links)
This thesis is focused on hash families and cover-free families and their application to problems in cryptography. We present new necessary conditions for generalized separating hash families, and provide new explicit constructions. We then consider three cryptographic applications of hash families and cover-free families. We provide a stronger de nition of anonymity in the context of shared symmetric key primitives and give a new scheme with improved anonymity properties. Second, we observe that nding the invalid signatures in a set of digital signatures that fails batch veri cation is a group testing problem, then apply and compare many group testing algorithms to solve this problem e ciently. In particular, we apply group testing algorithms based on cover-free families. Finally, we construct a one-time signature scheme based on cover-free families with short signatures.
24

Exploring persons’ experiences of keeping in touch with loved ones who have died

Upright, Christine Margaret 04 September 2009 (has links)
This descriptive, exploratory study framed within Parse’s theory of humanbecoming, addressed the research question: What is the meaning of persons’ experiences of keeping in touch with their loved ones who have died. Seven persons described their experiences of keeping in touch with their loved ones who had died. Study themes in the language of the participants were treasured events and signs give rise to lasting comfort while constant yet changing bonds come with turmoil and tranquility amid unfolding strength and confidence. Interpreted in the language of the researcher, study findings were written as cherished ciphers and occurrences engender solace as enduring-shifting ties abide with ease unease amid fortifying expansion. Study themes were linked primarily with theoretical concepts of valuing imaging, connecting-separating, and transforming. Findings were discussed in light of relevant literature, and possibilities for nursing practice, education, policy, and further research were offered.
25

Integrating farming and wastewater management : a system perspective /

Tidåker, Pernilla, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.
26

Preparação de membranas tubulares compósitas e sua avaliação na separação de emulsão óleo/água: utilização e reutilização.

MOTA, Joseane Damasceno. 10 April 2018 (has links)
Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-10T16:47:26Z No. of bitstreams: 1 JOSEANE DAMASCENO MOTA - TESE (PPGEQ) 2017.pdf: 3916496 bytes, checksum: b5339c38dab725355adc81c735faac81 (MD5) / Made available in DSpace on 2018-04-10T16:47:27Z (GMT). No. of bitstreams: 1 JOSEANE DAMASCENO MOTA - TESE (PPGEQ) 2017.pdf: 3916496 bytes, checksum: b5339c38dab725355adc81c735faac81 (MD5) Previous issue date: 2017-10-05 / Capes / Neste trabalho foram produzidas membranas tubulares poliméricas (Polietileno de ultra alto peso molecular - PEUAPM) e compósitas (PEUAPM/argila Chocolate B organofílica e PEUAPM/zeólita Mordenita) por sinterização visando sua utilização e reutilização no processo de separação de emulsão óleo/água. O mesmo trata do efeito da incorporação de 1, 3 e 5% em massa de argila Chocolate B organofílica ou zeólita Mordenita e diferentes tempos de sinterização (60, 90 e 120 min) no desempenho de membranas a base de PEUAPM. O PEUAPM foi caracterizado por meio das técnicas de Difratometria de raios X (DRX), Análise Termogravimétrica (TG) e Microscopia Eletrônica de Varredura (MEV). A argila Chocolate B natural e organofílica foi caracterizada por meio das técnicas de DRX, Capacidade de troca catiônica (CTC) Espectroscopia de Infravermelho por Transformada de Fourrier (FTIR), Análise Termogravimétrica (TG), MEV e Espectroscopia de Fluorescência de raios X por Energia Dispersiva (FRX-ED), enquanto que a zeólita Mordenita foi caracterizada por DRX, FRX-ED e MEV. O DRX confirmou que o PEUAPM é um polímero semicristalino, assim como o MEV provou que este é composto basicamente por aglomerados de partículas com tamanhos diferentes. O TG evidenciou que as membranas poderão resistir a variações de temperaturas moderadas sem perder sua integridade estrutural. As técnicas de caracterização (DRX, FTIR, TG) evidenciaram a efetiva intercalação dos cátions quaternários de amônio nas camadas interlamelares da argila. A partir dos resultados obtidos para a síntese de zeólita mordenita confirmou que a sua obtenção foi efetiva com formação da zeólita mordenita em fase pura e cristalina. Foram realizados testes de resistência química, capacidade de absorção de água e porosidade, além de caracterização de DRX e MEV das membranas tubulares poliméricas e compósitas. Os resultados das membranas permitiram inferir que tanto a incorporação de argila Chocolate B quanto da zeólita Mordenita provocaram melhorias nas membranas compósitas, tendo em vista que pelo DRX houve a confirmação do processo de intercalação das cadeias poliméricas entre as camadas da argila Chocolate B organofílica. Quando comparado com os resultados das membranas poliméricas, percebeu-se que as membranas tubulares compósitas apresentaram melhor estabilidade e resistência química e física com testes de capacidade de absorção de água, resistência química e porosidade. Verificou-se que a incorporação da argila Chocolate B organofílica e da zeólita Mordenita ocasionaram o aumento dos fluxos como também um acréscimo no percentual de rejeição (até 90,67%) das membranas quando comparadas com as membranas tubulares poliméricas. O processo de limpeza das membranas reutilizadas provou-se eficiente, com obtenção de mais de 99% de seu fluxo recuperado, assim como mais de 95% de seu potencial de rejeição restaurado. Dessa maneira, as membranas compósitas configuram-se como materiais promissores no tratamento de efluentes oleosos. / In this work, polymeric tubular membranes (PEUAPM) and composites (PEUAPM/ organophilic Chocolate B and PEUAPM/zeolite Mordenite) were produced by sintering for their use and reuse in the oil/water emulsion separation process. The same deals with the effect of the incorporation of 1, 3 and 5% by mass of organophilic Chocolate B clay or Mordenite zeolite and different sintering times (60, 90 and 120 min) in the performance of PEUAPM based membranes. The PEUAPM was characterized by the techniques of X-ray diffraction (XRD), Thermogravimetric Analysis (TG) and Scanning Electron Microscopy (SEM). The natural and organophilic Chocolate B clay was characterized by the techniques of XRD, Cation Exchange (CTC), Infrared Spectroscopy by Fourrier Transform (FTIR), Thermogravimetric (TG), SEM and X-ray Fluorescence Spectroscopy by Energy Dispersive (FRX-ED), while the Mordenite zeolite was characterized by DRX, FRX-ED and MEV. The XRD confirmed that PEUAPM is a semi-crystalline polymer, as well as SEM has proved that it is basically composed of particle agglomerates of different sizes. TG evidenced that membranes will be able to withstand moderate temperature variations without losing their structural integrity. Characterization techniques (XRD, FTIR, TG) evidenced the effective intercalation of the quaternary ammonium cations in the interlamellar layers of the clay. From the results obtained for the synthesis of mordenite zeolite confirmed that its obtaining was effective with formation of pure and crystalline phase mordenite zeolite. Tests of chemical resistance, water absorption capacity and porosity were performed, as well as characterization of XRD and MEV of polymeric and composite tubular membranes. The results of the membranes allowed to infer that both the incorporation of Chocolate B clay and the Mordenite zeolite caused improvements in the composite membranes, considering that by the XRD there was confirmation of the intercalation process of the polymer chains between the layers of the organophilic Chocolate B clay. When compared to the results of the polymer membranes, it was observed that the composite tubular membranes presented better stability and chemical and physical resistance with tests of water absorption capacity, chemical resistance and porosity. The incorporation of the organophilic Chocolate B clay and the Mordenite zeolite resulted in an increase in the fluxes as well as an increase in the rejection percentage (up to 90.67%) of the membranes when compared to the polymeric tubular membranes. The process of cleaning the reused membranes has proved to be efficient, obtaining more than 99% of its recovered flux, as well as more than 95% of its restored rejection potential. In this way, the composite membranes are configured as promising materials in the treatment of oily effluents.
27

Concentração e dispersão do poder político nas organizações coletivas finalísticas. Regime jurídico da companhia aberta integrante do novo mercado da bolsa de valores: o papel decisivo desempenhado pelos instrumentos jurídicos de dissociação entre representatividade política e participação economica de acionistas no âmbito da companhia / Concentration and dispersion of political power in organization: legal regimen of disperted ownership companies in the Brazilian novo market: the separation of ownership and cash-flow rights.

Luís André Negrelli de Moura Azevedo 16 April 2015 (has links)
Ao redor do mundo, a maioria das companhias listadas de grande porte tem acionista controlador, à exceção dos EUA e do RU, em que o comando da atividade empresarial é exercido, de fato, pelos administradores. A conformação de controle dominante em cada país resulta de uma série de fatores, muitos deles de ordem jurídica, os quais levam ao surgimento e permanência de uma dessas variantes, ao mesmo tempo em que parecem inibir o desenvolvimento da estrutura alternativa. A gradativa convergência global dos padrões de propriedade acionária a um denominador comum, aparentemente em curso - dos extremos da dispersão e concentração absolutas para o cenário intermediário dos blocos de participação minoritária relevante detidos por investidores institucionais não tem sido acompanhada de transformações significativas nas estruturas de poder de controle interno dominantes em cada país, as quais, em essência, continuam as mesmas. Isso significa que os fatores (jurídicos, especialmente) que levam à predominância de tais estruturas continuam em atuação, não obstante modificações havidas no grau de dispersão do capital com direito a voto de companhias listadas. Este trabalho visa apresentar um conjunto mais específico de fatores jurídicos que, ao mesmo tempo e de modo decisivo, favorecem a proliferação de uma dentre as duas estruturas de controle consideradas (controle acionário ou gerencial) e inibem o desenvolvimento de outra. Trata-se dos instrumentos jurídicos de dissociação entre representatividade política e participação econômica de acionistas, os quais exercem papel central na conformação do regime jurídico das companhias abertas com elevada dispersão do capital votante, integrantes do Novo Mercado da BVSP. / Most of the large listed companies outside USA and UK have a controlling shareholder. The dominant control structure in each country is the result of multiple determinants, many of them arising from the legal system. The gradual convergence of ownership patterns around the world from the extremes of the total concentration and separation of ownership and control to the intermediate scenario of significant blockholdings held by institutional investors - has not been accompanied by a relevant shift in the control structures in listed companies of most of the countries, specially those in the Brazilian Novo Mercado. This Doctorate Thesis presents a specific subset of legal factors contributing for that outcome: the legal instruments separating voting rights from cashflow rights.
28

Evaluation of Rural Sanitation Alternatives in Nepal Using Decision Support System (DSS) Approach

Rupakheti, Sanjib January 2013 (has links)
A society´s health depends on the access to proper and hygiene sanitation. Half of the population still do not have access to proper sanitation in Nepal; therefore government and non-government organizations are facilitating sanitation access to all the population. Decades ago, open defecation and pit latrines toilet were the only options as sanitation system to the people. But now, various types of toilets system known as dry toilets, septic tanks, centralized sewerage system and biogas integrated toilets are available. Therefore, existing toilet system in rural areas of Nepal needs to be evaluated with respect to environment and long term sustainability. Aim of this study is to find the appropriate toilet system for rural areas of Nepal. This study also discusses how that appropriate toilet system can be promoted based on current scenarios from government level to local level. Generic Multi-Attribute Analysis (GMAA) is used as a decision support tools to evaluate available various toilet alternatives. For which a rural area from Nepal is chosen as study area. GMAA helps in evaluating all the toilet system based on social, technological, environmental and economical aspects. Interpretation between the toilet systems can be made easily with the help of GMAA results. Field questionnaire survey was also carried out in the study area to know user´s understanding of toilet alternatives. Every toilet systems have pro and cons based on different social, technological, environmental and economical aspects. It was found that pit latrines toilet systems are mostly practiced in the rural areas of Nepal. User prefers pit latrines because of its social accepted character and technologically easy in using it. Biogas integrated toilet system came as optimal toilet system though not accessible to all household. It was found that urine and faeces separating toilets are environmentally and economically beneficial. The thesis concludes that appropriate toilet system which is sustainable must be promoted while increasing toilet coverage in Nepal. Urine and faeces separating toilet is found to be appropriate and need to be incorporated in the government goal of increasing toilet coverage.
29

Odpadové hospodárstvo v meste Bratislava / Waste Management in Bratislava

Gömöry, Michal January 2012 (has links)
The thesis deals with waste management in a particular city. It analyzes the level and trying to find opportunities for improvement. Analyzed government in Čunovo and Petržalka, next government in Bratislava and also higher territorial unit into which belongs Bratislava. Looked at the current level of support.Analysis will subjected to public and given internal documents,which are recovered. The results were confronted with a questionnaire research and his results. The company OLO, as the dominant element in city waste management, was also subjected to the research and findings have been recovered. All results were recovered and supplemented by observation Method of shopping centers and their access to sorting waste for visitors. Resulted in the appreciation of of each individual step of research and the actual proposals for improving the situation have been complex. Their combined implementation should be not only to improving waste management,but also to in a cost saving in terms of household. done not only to improve waste hos-ture, but also the financial savings in terms of households.
30

Finding Junctions in Spline-based Road Generation

Nyström, Isak, Darwiche, Danny January 2022 (has links)
Splines are a common mixed-initiative technique for road generation. A designer draws the shape of the curve but the mesh can be procedurally generated along the spline. This relationship improves the workflow of building roads in virtual environments and video games without taking away all of the control of the designer. Whilst this technique is useful when building single roads such as race tracks, it unfortunately struggles when dealing with more complex road networks that feature intersections. These intersections struggle with overlapping meshes and flickering textures without a straightforward solution. This problem significantly limits the usefulness of spline tools when generating roads. This paper aims to solve part of this problem by suggesting a method for detecting intersections in splines that support procedural mesh generation.

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