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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.
61

The EMF Measurement Of Aluminum Activity In Galvanizing

Jian, Bo-Lin 13 October 2011 (has links)
none
62

Preparation of Inorganic Tubular Membranes and Their Applications in Treatment of Chemical Mechanical Polishing

Li, Cyuan-jia 12 February 2006 (has links)
In this study, the wastewater from oxide chemical mechanical polishing (oxide-CMP) process of semiconductor wafer fabrication was treated by crossflow electro-ultrafiltration with self-prepared tubular inorganic membranes. First of all, a recipe of alumina (72 wt%), bentonite (8 wt%) and water (20 wt%) was determined for the extrusion of green tubes. The porous ceramic green tubes of 200 mm in length thus obtained were subjected to further curing, drying, and sintering processes. The inner and outer radii of the porous ceramic supports were 6.0 mm and 10.0 mm, respectively. Then, nanoscale TiO2 (i.e., the slip) was prepared by sol-gel method. On the tops of porous ceramic supports thin layers of nanoscale TiO2 were applied by the dip-coating method. To analyze the microstructures of tubular inorganic membranes and confirm the nanoscale TiO2 films, a scanning electron microscope equipped with energy-dispersive X-ray analyzer (SEM-EDS) and X-ray diffractometer (XRD) were employed. The self-prepared tubular inorganic composite membranes (TICMs) were futher characterized by permporometry and Kelvin equation to determine their pore size distributions and nominal pore sizes. In addition, through the employment of polyethylene glycol (PEG) of different molecular weights and total organic carbon analysis method, the molecular weight cut-off (MWCO) and tightness coefficient of each TICM was determined. It was found that the self-prepared TICMs were suitable for ultrafiltration applications. In this work, wastewater from the oxide-CMP process of semiconductor wafer fabrication was treated by crossflow electro-ultrafiltration with self- prepared TICMs. The permeate qualities were evaluated. Experimental results have shown that permeate of a higher filtration rate, a turbidity of below 1 NTU, 90% removal of total suspended solids, and a removal efficiency of greater than 80% for soluable silica could be obtained under the conditions of an electric filed strength of 30 V/cm and transmembrane pressure of 5 kgf/cm2. For permeate to meet the feed water requirements for the ultrapure water system, it has to be further treated to lower its silica content to ¡Ø 6 mg/L. Overall speaking, by incorporation of the tubular inorganic composite membranes prepared in this work into the novel electrofiltration treatment module for the treatment of oxide-CMP wastewater would yield permeate suitable for the purpose of reclamation.
63

Controlled nanostructure fabrication using atomic force microscopy

Sapcharoenkun, Chaweewan January 2013 (has links)
Scanning probe microscopy (SPM) nanolithography has been found to be a powerful and low-cost approach for sub-100 nm patterning. In this thesis, the possibility of using a state-of-the-art SPM system to controllably deposit nanoparticles on patterned Si substrates with high positional control has been explored. These nanoparticles have a range of interesting properties and have been characterised by electron microscopy and scanning probe microscopy. The influence of different deposition parameters on the nanoparticle properties was studied. Contact mode atomic force microscopy (AFM)-based local oxidation nanolithography (LON) was used to oxidise sample surfaces. Two different substrates were studied which were native oxide silicon (Si) and molybdenum (Mo). A number of factors that influence the height and width of the oxide features were investigated in order to achieve the optimal oxidation efficiency. The height and width of the oxide structures were found to be strongly dependent on the applied voltage and scan speed. The tunneling AFM (TUNA) technique was used to measure the ultralow currents flowing between the tip and the sample during the oxidation process. It was found that a threshold voltage for our oxidation experiments was -4.0 ± 1.6 V applied to the tip when fabricating geometric patterns as well as 2.9 ± 1.6 V and 2.8 ± 2.2 V applied to the substrate for nanodot fabrication. In addition, comparisons of nanodot-array patterns produced with different AFM tips were studied. The influence of applied voltage, type of AFM tip and substrate, humidity and ramping time has been studied for dot formation providing a comparison between native oxide Si and Mo surfaces. The nanodot sizes were found to be clearly dependent on the applied voltage, type of substrate, relative humidity and ramping time. Dip-pen nanolithography (DPN) was used to study a direct deposition strategy for gold (Au) nanodot fabrication on a native oxide Si substrate. In this process, hydrogen tetrachloroaurate (HAuCl4) molecules were deposited onto the substrate via a molecular diffusion process, in the absence of electrochemical reactions. This approach allowed for the generation of Au dots on the SiO2 substrate without the need for surface modification or additional electrode structures. The dependence of the size of the Au dots on different „scanning coating‟ (SC) times of AFM tips was studied. A thermal annealing process was used to decompose the generated HAuCl4 molecular dots to leave Au (0) metal dots. A stereomicroscope has been used for preliminary observation of different steps of Au deposition treatments. A scanning electron microscope (SEM) was used to characterise the SC AFM tips both before and after the DPN process. SEM energy-dispersive X-ray spectroscopy (EDS) has provided information about the elemental content of deposited particles for different annealing temperatures. Fountain-pen nanolithography (FPN) has also been used to study nanowriting of HAuCl4 salt and a variety of solvents on a native oxide Si surface. In this technique, a nanopipette was mounted within an AFM to deliver appropriate solutions to the silica substrate. We found that an aqueous Au salt solution was the most suitable ink for depositing gold using the FPN technique. In the case of solvents alone, ethanol and toluene were achieved with depositing onto a SiO2 substrate using the FPN technique.
64

A comparative study of inclinometers and time domain reflectometry for slope movement analysis

Sargent, Lisa M. January 2004 (has links)
Thesis (M.S.)--Ohio University, March, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 73-75).
65

Imobilização de íons ferricianeto sobre eletrodo de ouro e desenvolvimento de um sistema dip-coating para elaboração de eletrodos modificados

ALMEIDA JÚNIOR, Pedro Lemos de 27 March 2014 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-08-03T12:52:24Z No. of bitstreams: 1 Pedro Lemos de Almeida Junior.pdf: 3276258 bytes, checksum: 9cfc77040db57e5dc73048d5ce92da67 (MD5) / Made available in DSpace on 2017-08-03T12:52:24Z (GMT). No. of bitstreams: 1 Pedro Lemos de Almeida Junior.pdf: 3276258 bytes, checksum: 9cfc77040db57e5dc73048d5ce92da67 (MD5) Previous issue date: 2014-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The development of multilayer self-assembled films using the Layer Layer (LbL) approach has showed a high efficiency on the fabrication o ultrathin films. The LbL technique have been successfully and increasingly employed on developing new arquitectures for immobilization of enzymes, catalysts, electron mediators and other chemicals on conventional solid electrode surfaces for the development of electrochemical sensors and biosensors. This work followed two main paths: it was proposed the development and application of a new miniaturized dip-coating equipment, named LbL System, for the preparation of multilayers thin films on solid electrodes, and also a new method for the modification of gold electrodes for the immobilization of ferricyanide ions into a silica network, with application for the determination of nitrite ions. The proposed LbL System is automatic and has an embedded microcontroller that simplifies its hardware and software, and also favors its miniaturization. The system makes it possible all the modification process of being carried out automatically without attendance during the operation, only requiring the definition of some parameters by the user. The development of the equipment was based on a new concept of dip-coating, where, the solution flows to a fixed electrode instead of dipping the electrode in the solution, as it happens at all the commercial equipments, making possible to work with microvolumes of reagents and solutions keeping a high reproducibility of the modification process. The proposed new method for immobilization of ferricyanide ions on gold electrodes was based on its affinity with a silica network modified with a spacer containing amine terminal groups, anchored on the surface via silanol groups of the opposite terminal bound to other silanol groups of a self-assembled monolayer previously deposited on the metal. The gold modified electrode presents the voltammetric characteristic reversible signal of the redox pair Fe((III)/Fe(II), showing the maintenance of the Fe(III)/Fe(II) in the molecular arquitecture mounted on the metal surface. The modified electrode presented electrocatalytic activity for the reduction of nitrite ions and was successfully applied on a flow injection analysis system for analyses of natural waters, presenting a linear response range of 1x10-6 to 4x10-5 mol L-1 (r = 0.9995), with a detection limit of 0,53x10-6 mol L-1. / A elaboração de filmes contendo multicamadas automontadas utilizando a técnica camada sobre camada (LbL, do inglês “Layer by Layer”) tem se mostrado um método eficaz para a fabricação de filmes ultrafinos. Filmes LbL vêm sendo crescentemente empregados com sucesso na elaboração de novas arquiteturas para imobilização de enzimas, catalisadores, mediadores de elétrons e outras espécies na superfície de eletrodos sólidos convencionais para elaboração de sensores e biossensores eletroquímicos. Neste trabalho foram propostas duas vertentes. Primeiramente se descreve a fabricação e aplicação de um equipamento microcontrolado, denominado Sistema LbL, para a obtenção de filmes finos multicamadas sobre eletrodos sólidos. Em seguida se propõe um novo método para a modificação de eletrodo de ouro pela imobilização de íons ferricianeto em rede de sílica, com aplicação para determinação de íons nitrito. O Sistema LbL desenvolvido é automatizado e traz consigo um microcontrolador, que simplifica significativamente seu hardware e software, além de possibilitar sua miniaturização. O Sistema permite que todo o processo de modificação da superfície de eletrodos sólidos seja realizado automaticamente e sem requerer assistência durante a operação, cabendo ao usuário apenas a definição prévia de determinados parâmetros. O desenvolvimento do equipamento fundamentou-se em uma nova concepção de sistema dip-coating, em que ao invés de introduzir o eletrodo nas soluções, como realizado nos equipamentos comerciais, leva-se as soluções até o eletrodo, tendo como resultado um método de modificação que utiliza microvolumes de reagentes e soluções, com elevada reprodutibilidade do processo de modificação. O novo método, desenvolvido para imobilização de íons ferricianeto em eletrodo de ouro, baseou-se na afinidade dos íons ferricianeto por uma rede de sílica modificada com um espaçador contendo grupamentos amina terminais ancorado no eletrodo via grupos silanóis do terminal oposto, sendo este previamente fixado no eletrodo por condensação com grupos silanóis de uma monocamada automontada na superfície do ouro. Após a modificação, o eletrodo de ouro passa a apresentar o sinal voltamétrico reversível característico do par redox Fe(III)/Fe(II), demonstrando que a atividade redox é mantida na arquitetura molecular montada sobre a superfície do metal. O eletrodo modificado apresentou atividade eletrocatalítica para a redução de íons nitrito e foi aplicado com sucesso num sistema de análise por injeção em fluxo para análises de águas naturais, apresentando resposta linear na faixa de 1x10-6 a 4x10-5 mol L-1 (r = 0,9995), com limite de detecção de 0,53x10-6 mol L-1.
66

Revista Sintonia: Imprensa e poder político no Amazonas (1939-1943)

Mendonça, Reginaldo Simões 14 May 2015 (has links)
Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-11-13T20:37:01Z No. of bitstreams: 1 Dissertação - Reginaldo Simões Mendonça.pdf: 5377122 bytes, checksum: 4caf228a02be268f2d4fc0695c8bcdb3 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-11-27T19:42:29Z (GMT) No. of bitstreams: 1 Dissertação - Reginaldo Simões Mendonça.pdf: 5377122 bytes, checksum: 4caf228a02be268f2d4fc0695c8bcdb3 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-11-27T19:48:32Z (GMT) No. of bitstreams: 1 Dissertação - Reginaldo Simões Mendonça.pdf: 5377122 bytes, checksum: 4caf228a02be268f2d4fc0695c8bcdb3 (MD5) / Made available in DSpace on 2015-11-27T19:48:32Z (GMT). No. of bitstreams: 1 Dissertação - Reginaldo Simões Mendonça.pdf: 5377122 bytes, checksum: 4caf228a02be268f2d4fc0695c8bcdb3 (MD5) Previous issue date: 2015-05-14 / FAPEAM - Fapeam - Fundação de Amparo à Pesquisa do Estado do Amazonas / This research aims to demonstrate how political advertising in the press was used by Getúlio Vargas in the Amazon as convincing vehicle of the population in search of support for his political project, and as a control mechanism ,established both through diffuse through censorship and performance of the Departamento de Imprensa e Propaganda (DIP), the more directly , with the political persecution of its opponents. In this process, we seek to understand parallel as an important vehicle information, such as Revista Sintonia, established in Manaus by telegraph Rigoberto Costa in 1939 - and whose existence lasted, with interruptions, until 1954 - allied to that propagandism, making it the cornerstone of its publication. The aim was also through the content analysis presented by the magazine check their editorial composition among its 41 copies seeking to understand their intellectual and informative dynamism. / A presente pesquisa tem por objetivo demonstrar como a propaganda política na Imprensa foi utilizada por Getúlio Vargas no Amazonas como veículo de convencimento da população em busca de apoio a seu projeto político, e como mecanismo de controle, estabelecido tanto por meio difuso através da censura e atuação do Departamento de Imprensa e Propaganda (DIP), quanto de forma mais direta, com a perseguição política a seus opositores. Neste processo, busca-se paralelamente compreender como um importante veículo informativo, como a Revista Sintonia, criada em Manaus pelo telegrafista Rigoberto Costa, em 1939 – e cuja existência prolongou-se, com interrupções, até 1954 –, aliou-se a esse propagandismo, fazendo dele a pedra de toque de sua publicação. Buscou-se também através das análises de conteúdo apresentado pela própria revista verificar a sua composição editorial entre os seus 41 exemplares procurando entender seu dinamismo intelectual e informativo.
67

Financiamento das empresas em crise / Financing for distressed companies.

Leonardo Adriano Ribeiro Dias 07 December 2012 (has links)
O presente trabalho tem por finalidade analisar o problema do financiamento das empresas em crise no Brasil e a disciplina a ele conferida pela Lei n. 11.101/05, com enfoque no procedimento de recuperação judicial. Após uma breve análise das diversas causas da crise empresarial e de possíveis medidas saneadoras preliminares, inicia-se a discussão das premissas constitucionais do tratamento das empresas em dificuldade no Brasil e dos objetivos da lei falimentar em geral, para então ingressar nas soluções adotadas pelo direito brasileiro. Em seguida, tem início o escrutínio do tema central proposto, com destaque para seu escopo e importância, além da identificação dos meios, agentes e modalidades relacionados ao financiamento das empresas em dificuldade. Apresentado um sucinto panorama da matéria no direito estrangeiro, investiga-se o tema à luz do ordenamento pátrio, numa abordagem teórica e prática do financiamento das empresas em crise no Brasil e seus limitadores, assim como possíveis alternativas para mitigá-los. O problema é tratado, ainda, sob a perspectiva da governança corporativa e, por derradeiro, vislumbra-se sua eventual adoção na falência, com escoro no princípio da preservação da empresa, passando-se à conclusão. / The present work has the aim of analyzing the problem of financing for distressed companies in Brazil and the discipline granted to it by Law no. 11.101/05, with focus on the judicial reorganization procedure. After a brief analysis of the various causes of corporate crisis and the possible preliminary aid measures, a debate commences on the constitutional premises of the treatment of distressed companies in Brazil and the goals of bankruptcy law in general, after which the solutions adopted by Brazilian Law are examined. Next, the scrutiny of the proposed theme begins, with emphasis on its scope and importance, as well as the identification of the means, participants and categories related to the financing for companies in difficulties. After the presentation of a brief overview of the matter in foreign law, the same is investigated in light of the national legal system, under a theoretical and practical approach of financing for distressed companies in Brazil and its constraints, as well as the possible alternatives to mitigate them. In addition, the problem is treated from the perspective of the corporate governance and, last, a glimpse is taken into its eventual adoption in liquidation processes, with support in the principle of preservation of the company, culminating with the conclusion.
68

Investigação de fatores sorológicos e genéticos relacionados com a predisposição ao desenvolvimento das formas graves da dengue em Juiz de Fora

Siqueira, Tatiane Ribeiro de 26 February 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-09T14:33:14Z No. of bitstreams: 1 tatianeribeirodesiqueira.pdf: 1746220 bytes, checksum: 01a239ee1ea9876e3d413b78f8f1446b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-09T14:56:33Z (GMT) No. of bitstreams: 1 tatianeribeirodesiqueira.pdf: 1746220 bytes, checksum: 01a239ee1ea9876e3d413b78f8f1446b (MD5) / Made available in DSpace on 2015-12-09T14:56:33Z (GMT). No. of bitstreams: 1 tatianeribeirodesiqueira.pdf: 1746220 bytes, checksum: 01a239ee1ea9876e3d413b78f8f1446b (MD5) Previous issue date: 2015-02-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A infecção por dengue vírus (DENV) tem sido considerada atualmente a mais importante arbovirose no mundo. Até o presente momento foram descritos quatro diferentes sorotipos do DENV: DENV-1, DENV-2, DENV-3 e DENV-4. A infecção pelo DENV pode produzir uma ampla variedade de distúrbios a febre do dengue ou formas graves da doença, como a febre hemorrágica do dengue (FHD) e síndrome do choque do dengue (SCD), onde os quatro sorotipos de DENV podem causar desde uma infecção assintomática até FHD e SCD. A patogênese da FHD/SCD é multifatorial e vários estudos mostram algumas hipóteses para explicar as manifestações mais graves na infecção por DENV: (i) fatores virais, (ii) associação entre FHD/SCD em casos de infecção heterotípica pelo DENV e (iii) fatores do próprio hospedeiro, que poderiam estar relacionados à resposta imune. Estudos que buscam entender o porquê de pacientes com dengue apresentarem diferentes prognósticos são de grande importância para a Saúde Pública. Embora a doença causada por DENV seja considerada um grande problema de saúde pública, ainda não estão disponíveis drogas antivirais e vacinas a fim de tratar ou prevenir a infecção. O combate do vetor tem sido ineficiente, permitindo o aparecimento de novas epidemias. A cidade de Juiz de Fora vem passando por diversas epidemias de dengue nos últimos anos, com o registro de casos graves e óbitos. Diante deste contexto, este trabalho visou investigar os fatores sorológicos e genéticos relacionados com a predisposição ao desenvolvimento das formas graves de dengue em Juiz de Fora. Em setembro e outubro de 2013 e fevereiro e maio de 2014, amostras de sangue total foram coletadas. As amostras foram estudas para estudos de SNPs, pequisa de anticorpos e do DENV. No grupo estudado, foi observada uma soroprevalência de 16,1%. Foram detectados genótipos predisponentes e genótipos protetores de FHD, nos genes FCRIIa, JAK-1 e DCSIGN, em moradores de Juiz de Fora, entretanto, não foi observada associação desses genótipos individualmente e/ou em combinação com a distribuição de gênero, diferentes regiões de Juiz de Fora onde os participantes residiam e relato de apresentação de sintomas de dengue pelos pacientes. Foram detectados três pacientes que apresentaram material genético de DENV. O conhecimento de áreas e pessoas predispostas à FHD constituem informações valiosas do ponto de vista epidemiológico e na estruturação de políticas públicas que visem o controle da dengue. / Dengue virus infection (DENV) is considered the most important arbovirose in the world and the greatest impact on public health. Four different serotypes of DENV: DENV-1, DENV-2, DENV-3 and DENV-4 have been described. DENV infection may produce a wide variety of disorders, dengue fever or severe disease, such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (SCD). Any of the four DENV can cause asymptomatic infection from one to DHF and DSS. The pathogenesis of DHF / DSS is multifactorial and several studies showed some hypotheses to explain the most serious manifestations of infection by DENV: (i) viral factors (ii) secondary infection DENV and (iii) the host factors could be related to exaggerated immune response. Studies trying to understand why dengue patients have different prognoses are of great importance for public health. Although dengue is considered one major public health problem, there are not available antiviral drugs and vaccines to treat or prevent the infection. The vector control has been inefficient, allowing the emergence of new outbreaks. The city of Juiz de Fora has experienced several dengue epidemics in recent years, with the record of serious cases and deaths. Given this context, this study aimed to investigate the serological and genetic factors related to the predisposition to severe forms of dengue in Juiz de Fora. In September/ October 2013 and February to May 14 342 samples of whole blood were collected were collected. Samples were used to investigate the immune response do dengue, SNPs and DENV. In the study group, a seroprevalence of 16.1% was observed. Predisponent and protector genotypes were detected genes FCyRIIa, JAK-1 and DCSIGN in Juiz de Fora residents, however, there was no association of these genotypes individually and / or in combination with the gender distribution, different Juiz de Fora regions where the participants lived and report presentation of dengue symptoms by patients. Three patients were detected with DENV infection, by the time of sample collection.The knowledge of areas and persons who are more prone to have FHD is a valuable information from the epidemiological point of view and the structuring of public policies aimed at controlling dengue.
69

Příprava tenkostěnných dutých keramických vláken metodou povlakování namáčením / Preparation of thin wall ceramic hollow fibers by dip-coating

Gockert, Radek January 2017 (has links)
Tato diplomová práce se zabývá výrobou ultratenkých keramických dutých vláken pomocí metody povlakování namáčením. Příprava keramických dutých vláken je v současnosti limitována rozměrem vnějšího a vnitřního průměru. Aplikace metody povlakování namáčením pro přípravu ultratenkých dutých je nový a technologicky náročný proces vyžadující volbu vhodné šablony a zároveň zvládnutí kontroly parametrů povlakování. Základními zvolenými materiály s vysokým aplikačním potenciálem jsou hydroxyapatit a oxid titaničitý. Samonosná dutá vlákna s tloušťkou stěny pod 1 m byla úspěšně připravena z obou materiálů. Dále byl také popsán proces povlakování namáčením obětovaných šablon. Tato metoda je unikátní, protože umožňuje produkci ultratenkých keramických dutých vláken s vnitřním průměrem pod 100 m a tloušťkou stěny pod 1 m.
70

Reologické vlastnosti gelů pro Pechiniho syntézy / Rheological properties of gels for Pechini syntheses

Wirthová, Michaela January 2009 (has links)
This work deals with preparation of layers of ceramic materials – perovskites. The introductory part includes general characteristics concerning structure, properties and use of this materials. In details then there is described method of their preparation, namely Pechini´s syntheses, which are most widely used. Optimum molar ratio of components is discussed, in the sense of what compositions lead to creation of perovskite structures. Influence of this parameter on rheological properties of precursory gels is described in the end of the first part of work. In experimental section there are described preparations of gels, which are prepared via reaction between citric acid and ethylene glycol and gels, which are prepared by Pechini´s synthesis. Rheological properties of prepared gels (density, viscosity and surface tension) and besides determination of amount of nitrates in gels are characterized. Temperature dependence of viscosity of gels, that are prepared by reaction of citric acid and ethylene glycol are determined. In final part successful preparations of perovskite layers is shown on ceramic substrate. This layers are observed by means of light optical microscope and scanning electron microscope.

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