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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.
181

Visuell hierarki och läsmönster : en studie om kontrast, storlek och positionering

Sova, Jemi, Karim, Bobby January 2013 (has links)
Syftet med denna uppsats är att identifiera den mest effektiva egenskapen av en text eller sida för att uppnå visuell hierarki, som är ett verktyg för att få det önskade flödet av uppmärksamhet i en sida eller webbsida genom att ge vissa element en viss vikt i kontrast, storlek och placering. Vi vill ge en möjlighet för vidare forskning snarare än att ge en slutsats som ger ett slutgiltigt svar på frågeställningarna. Det finns fler sätt att manipulera text för att uppnå önskad visuell hierarki men vi valde de vanligaste. Detta arbete är baserat på ett experiment som görs på 50 deltagare med ett onlinefrågeformulär och tre självgjorda bilder där vi kan utvärdera resultaten, jämföra dem med andra teorier och beräkna den mest effektiva uppmärksamhetsgivaren. Vi har också utvecklat en hypotes om vad resultatet kommer att visa. Vår studie föreslår att kontrasten i färg kan vara den viktigaste faktorn för att uppnå och upprätthålla visuell hierarki. / The purpose of this paper is to identify the most effective property of a text or a page to achieve visual hierarchy, which is a tool for getting the desired flow of attention in a page or a web page by giving certain elements a degree of weight in contrast, size and positioning.We want to give an opportunity for further research rather than an absolute conclusion of how it really is. There are more ways to manipulate text to achieve the desired visual hierarchy but we choose the most common. This paper is based on an experiment involving 50 participants with an online questionnaire and three self-made pictures where we will evaluate the results, compare them with other theories and calculate the most effective enhancer of attention. We have also developed a hypothesis on what the results will show. Our study proposes that contrast in color might be the most important factor to achieve and maintain visual hierarchy.
182

Experimentellt vidareutvecklad modell för dimensionering av skadebegränsandeåtgärder mot RSV-penetration vid ammunitionsröjning / Experimentally developed model for the design of protective measures againstshaped charge jet penetration during EOD operations

Johnsson, Fredrik January 2014 (has links)
Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten. Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd. Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts. Härefter har Monte Carlo-simulering använts för att analysera den sammanlagda inverkan som dessa fel kan ge. Resultatet har legat till grund för att bestämma modellens säkerhetsmarginal. Militär nytta innebär att modellen skall kunna tillämpas fältmässigt, med korta tidsförhållanden och utan tillgång till avancerade beräkningshjälpmedel. Detta har lett fram till att ett enkelt diagram inkluderats i det kompletta dimensioneringsverktyget. Verktyget föreslås införas i regelverk och utbildningssystem för att avhjälpa den brist som råder idag. / During the clearance of shaped charge ammunition, explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jet. In this thesis a calculation model, previously suggested by the author, is developed further. The aim is to create a tool that can be applied to EOD operations. Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions. Furthermore, a sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction. By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the effect these errors can cause. The simulation results have then been the used to determine the model´s margin of safety. Military utility implies that it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in the comprehensive design tool. It is proposed that the tool is implemented in regulations and curricula in order to remedy today’s lack of decision support.
183

ADVANCED RANGE TELEMETRY (ARTM) TIER I COMPATIBLE DEMODULATOR TESTING AND RESULTS

Temple, Kip 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The Nova HYPERMOD demodulator operates in three modes, the classic pulse-code modulation/frequency modulation (PCM/FM), sometimes known as continuous phase frequency shift keying (CPFSK) mode, shaped offset quadrature phase shift keying (SOQPSK) mode, and continuous phase modulation (CPM) mode. Of interest to this paper is SOQPSK mode which is a waveform similar to the Advanced Range Telemetry (ARTM) Tier I waveform, Feher’s Quadrature Phase Shift Keying, B version (FQPSK-B) revision (Rev) A1. Also considered is another variant, FQPSK-JR. This paper will outline the cross compatibility and resynchronization speed of these waveforms based upon ARTM-adopted demodulator performance tests. The results of these laboratory tests comparing the HYPERMOD demodulator, the enhanced Tier I demodulator, and the current Tier I reference demodulator, both from RF Networks, will be presented.
184

FABRICATION AND STUDY OF AC ELECTRO-OSMOTIC MICROPUMPS

Guo, Xin 07 May 2013 (has links)
In this thesis, microelectrode arrays of micropumps have been designed, fabricated and characterized for transporting microfluid by AC electro-osmosis (ACEO). In particular, the 3D stepped electrode design which shows superior performance to others in literature is adopted for making micropumps, and the performance of such devices has been studied and explored. A novel fabrication process has also been developed in the work, realizing 3D stepped electrodes on a flexible substrate, which is suitable for biomedical use, for example glaucoma implant. There are three major contributions to ACEO pumping in the work. First, a novel design of 3D “T-shaped” discrete electrode arrays was made using PolyMUMPs® process. The breakthrough of this work was discretizing the continuous 3D stepped electrodes which were commonly seen in the past research. The “T-shaped” electrodes did not only create ACEO flows on the top surfaces of electrodes but also along the side walls between separated electrodes. Secondly, four 3D stepped electrode arrays were designed, fabricated and tested. It was found from the experiment that PolyMUMPs® ACEO electrodes usually required a higher driving voltage than gold electrodes for operation. It was also noticed that a simulation based on the modified model taking into account the surface oxide of electrodes showed a better agreement with the experimental results. It thus demonstrated the possibility that the surface oxide of electrodes had impact on fluidic pumping. This methodology could also be applied to metal electrodes with a native oxide layer such as titanium and aluminum. Thirdly, a prototype of the ACEO pump with 3D stepped electrode arrays was first time realized on a flexible substrate using Kapton polyimide sheets and packaged with PDMS encapsulants. Comprehensive experimental testing was also conducted to evaluate the mechanical properties as well as the pumping performance. The experimental findings indicated that this fabrication process was a promising method to create flexible ACEO pumps that can be used as medical implants and wearable devices. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-05-06 10:57:48.077
185

Preparation, characterization, and rheological properties of star-shaped poly(ethylene glycol) with a cholane core and study of its effect on red blood cell aggregation

Janvier, Florence January 2009 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
186

Mikroparaziti a plodnost perlooček rodu Daphnia na gradientech v korytovitých přehradních nádržích / Microparasites and fecundity of Daphnia at environmental gradients of canyon-shaped reservoirs

Hubová, Jana January 2015 (has links)
The original aim of my diploma thesis was examination of fixed samples of cladocerans from the Daphnia longispina species complex from reservoirs Vír and Vranov for the presence of 4 groups of microparasites: microsporidia, oomycetes, the protozoan Caullerya mesnili, and the yeast Metschnikowia bicuspidata. The next aim was to determine the effect of parasites on Daphnia fecundity, and determination of their spatial and temporal distribution within reservoirs. From the total number 4452 of examined Daphnia females, however, only 56 individuals were infected. This number was not sufficient for the planned analyses. As I recorded for all examined individuals the clutch size, I thus dealt to a large extent with an alternative issue: the temporal and spatial variation of, and the influence of environmental factors on Daphnia fecundity. Both studied reservoirs are characteristic by canyon-shaped profile that allows formation of environmental gradients on the horizontal as well as vertical axis. The results confirm that reservoir identity, season, and location within the reservoir (or gradient of food supply) have all significant effects on fecundity. During my work I have encountered difficulties associated with determining microparazites from fixed zooplankton samples. The appendix section of my thesis...
187

Caracterização aerodinâmica de edifícios altos com planta em formato de “V” através de análise espectral

Vogado, Monique Wesz January 2018 (has links)
Nas últimas décadas, tem-se observado uma forte tendência de edificações cada vez mais altas, esbeltas e flexíveis, o que exigiu novas considerações no cálculo estrutural de edifícios, tornando a ação do vento um elemento de grande relevância nos projetos. Além disso, o denso agrupamento de edificações nos centros de grandes cidades adicionou uma variável para um fenômeno que já era complexo: devido à proximidade, um edifício passa a influenciar o campo aerodinâmico de outros, podendo provocar grandes alterações nas pressões, além de fenômenos dinâmicos difíceis de determinar por métodos analíticos. Instruções normativas, em geral, limitam-se a prédios altos com padrões arquitetônicos regulares, afastando-se da realidade dos projetos construídos na prática, que vêm exibindo geometrias cada vez mais complexas e não convencionais. Este cenário justifica a realização de extensos estudos dentro do tema em questão, a fim de que se obtenha uma melhor compreensão dos fenômenos dinâmicos envolvidos e uma orientação mais abrangente na etapa de pré-dimensionamento da estrutura. Neste contexto, a proposta desta pesquisa consiste em dois estudos de caso, de edifícios construídos no Brasil e ensaiados em túnel de vento, que possuem uma geometria similar (em formato de “V”), mas com dimensões e detalhes arquitetônicos distintos. O objetivo é o de promover uma caracterização aerodinâmica, avaliando os carregamentos atuando global e localmente, tanto para o modelo considerado isolado quanto incluindo as condições de vizinhança. Além das ações, estudou-se o espectro do vento que se aproxima, e determinou-se as funções de admitância aerodinâmica correspondentes. Em ambos os edifícios, verificou-se que a incidência do vento aproximadamente perpendicular a uma das abas corresponde a uma direção crítica em termos de efeitos dinâmicos: os espectros dos carregamentos globais se mostraram muito similares, apresentando picos pronunciados que indicam a possibilidade de desprendimento cadenciado de vórtices; as funções de admitância aerodinâmica também evidenciaram um formato muito semelhante. O estudo em questão oferece um meio de validação para estudos futuros que utilizem modelos de ensaio simplificados, além de servir de referência para uma possível revisão da norma brasileira NBR 6123/1988 – Forças devidas ao vento em edificações, contribuindo com os avanços do conhecimento relativo a efeitos dinâmicos do vento em edifícios altos e irregulares. / In the last decades we observed a strong trend in constructing buildings increasingly tall, slender and flexible, which has asked for new consideration in the structural calculus of buildings, making the wind a relevant element in the design procedures. The grouping of buildings downtown in big cities has added another variable to an already complex phenomenon: due to the proximity, a building influences in the aerodynamic field of others, leading to pressure modifications and dynamic effects hard to determine by analytical methods. Instruction codes, in general, are limited to regular tall buildings, in contrast to the reality of projects built in practice, which have been exhibiting architectonic patterns increasingly complex and unconventional. This scenario justifies extensive studies among aerodynamic of irregular tall buildings, with the purpose of acquiring a better comprehension regarding the dynamic phenomena involved and a more accurate direction on the pre-design phase. In this context, the proposal of this research consists of two case studies about buildings constructed in Brazil and tested in wind tunnel, which have a similar geometry (V-shaped) but different dimensions and architectonic details. The objective is to promote a complete aerodynamic characterization, assessing the loads acting as a whole and also locally, with both isolated and interference conditions. Besides the action, the velocity spectrum of the approaching wind and the corresponding aerodynamic admittance were studied. Either case, it was verified that the wind incidence nearly perpendicular to one of the frontal facades is a critical direction from the perspective of dynamic effects: the spectra of global loads were very similar, with a peak emerging on the graphs, which indicate the possibility of vortex shedding; the admittance function also showed a very close format. This study offers an instrument of validation for future researches that use simplified test models, besides to fit as a reference to a possible revision of the Brazilian code NBR 6123/1988 – Wind load on building structures, contributing to the knowledge advances regarding dynamic effects on irregular tall buildings.
188

Contribuição ao projeto de vigas delgadas de seção \"L\" de concreto pré-moldado / Contribution to the design of precast concrete slender L-shaped beams

Pastore, Marcus Vinícius Filiagi 05 August 2015 (has links)
Esta dissertação tem por objetivo contribuir para o projeto estrutural de vigas delgadas de seção \"L\" de concreto pré-moldado, também conhecidas no Brasil como vigas suporte-peitoril. O projeto deste tipo de viga apresenta uma maior complexidade que o de vigas usuais pela seção transversal assimétrica, carregamento excêntrico e as várias possibilidades de ligações viga-pilar e viga-laje. Em função de sua ligação com a laje, o comportamento deste tipo de viga pode apresentar diferentes modelos: a) com torção de equilíbrio; b) sem torção de equilíbrio; e c) com restrição parcial da rotação da laje. É mostrado que para relações altura da viga/largura da mesa inferior maiores que 2,5, a variação da orientação dos eixos principais de inércia com relação aos eixos vertical e horizontal pode ser desprezada. Além disso, o centro de cisalhamento pode ser considerado situado na linha de centro da alma para grandes relações altura da viga/altura da aba. Também são discutidas as ações e efeitos a serem considerados no projeto de vigas de seção \"L\". Em relação ao estado limite último, é mostrado que os procedimentos de dimensionamento de momento fletor e força cortante não diferem dos outros tipos de vigas de concreto, entretanto, o momento de torção pode ser tratado como flexão de placa por um método recomendado na última revisão do ACI-318. O comportamento da ligação alma/aba é considerado como dente de concreto e os seguintes aspectos de seu dimensionamento são apresentados: cálculo do tirante, cálculo da suspensão, cálculo da armadura longitudinal e verificação da biela crítica. Além disso, é levada em conta a resistência à punção da aba para efeito de forças concentradas. Também são discutidas as considerações para a flexão do peitoril que pode ocorrer pela ação lateral do vento e do impacto de veículos. Em relação ao estado limite de serviço, são apresentadas duas situações exclusivas para vigas de seção \"L\" com peitoril alto e delgado: formação de fissuras na extremidade e deformação lateral excessiva. Por fim, um exemplo de aplicação é desenvolvido para ilustrar particularidades no dimensionamento de vigas delgadas de seção \"L\" de concreto pré-moldado. / This thesis aims to contribute to the structural design of precast concrete slender L-shaped beams, also known as facade beams, spandrel beams, L-shaped edge beams and others. The design of these beams shows a greater complexity than usual concrete beams due to the asymmetric cross section, eccentric loads and the various possibilities for beam-column and beam-slab connections. According to their connection with the slab, the beam behavior can be divided into different models: a) with equilibrium torsion; b) without equilibrium torsion; c) with partial restriction of the slab rotation. It is shown that for height-to-total width ratios larger than 2.5, the variation of the orientation of the principal axes with respect to the vertical and horizontal axes can be neglected. Furthermore, the shear center can be considered located at the web center line for high values of the beam height-to-ledge height ratio. It is also discussed the actions and effects to be considered in the design of L-shaped beams. Regarding the ultimate limit state, it is shown that the bending moment and shear force procedures do not differ from other types of concrete beams, however, the torsion can be treated as plate bending by a recent method recommended in the latest ACI-318 revision. The ledge is considered as dapped end beams and the following aspects of its design are presented: transverse bending; hanger requirements; longitudinal bending and shear strength, including punching shear. It is also discussed the considerations for web flexure that may occur by wind action and lateral vehicle impact. Regarding the serviceability limit state, it is presented two unique situations for precast concrete slender L-shaped beams: crack formation at end regions and excessive lateral deflection. Lastly, an example is developed to illustrate particularities of the precast concrete slender L-shaped beam design.
189

Estados ligados de Majorana em nanodispositivo com ponto quântico acoplado à cadeia de átomos em zigue zague sobre supercondutor topológico. / Connected states of Majorana in nanodispositivo with quantum dot coupled to the string of zigzag atoms over topological superconductor.

BEIRÃO, Antonio Thiago Madeira 11 October 2018 (has links)
Submitted by Luciclea Silva (luci@ufpa.br) on 2018-11-01T17:20:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_EstadosligadosMajorana.pdf: 5157889 bytes, checksum: a697f1a4428dbb52f1b3046f7b793221 (MD5) / Approved for entry into archive by Luciclea Silva (luci@ufpa.br) on 2018-11-01T17:20:40Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_EstadosligadosMajorana.pdf: 5157889 bytes, checksum: a697f1a4428dbb52f1b3046f7b793221 (MD5) / Made available in DSpace on 2018-11-01T17:20:40Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_EstadosligadosMajorana.pdf: 5157889 bytes, checksum: a697f1a4428dbb52f1b3046f7b793221 (MD5) Previous issue date: 2018-10-11 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A pesquisa em física da matéria condensada com isolantes e supercondutores topológicos tem contribuído muito para a caracterização das propriedades de superfície e de modos zero em nanofios. Investigamos teoricamente o transporte de elétrons através do ponto quântico em forma de T (PQ) com um único nível e spinless, conectado a uma cadeia em zigue zague e acoplado a um supercondutor p-wave, utilizando o método analítico recursivo de funções de green no equilíbrio. Este modelo é uma extensão da cadeia de Kitaev para uma rede triangular de tamanho finito com três, quatro e cinco sitios. Observamos que modos zero de Majorana podem ser sintonizados através dos parâmetros de acoplamento do dispositivo e a condutância linear mostra ambos os Estados Ligados de Majorana (MBS) na fase topológica e na fase topológica geral maximamente robusta. Este modelo mais realista permite a detecção de MBS através do controle dos parâmetros que governam o tunelamento eletrônico e pode ser útil para experimentos relevantes. / The research in condensed matter physics with insulators and superconductors topological has contributed greatly to the characterization of the surface properties and modes zero in nanowires. We investigate theoretically, through the recursive Green’s function approach, the electron transport through the T-shaped quantum dot (PQ) with a single level and spinless, connected to a zigue zague chain and coupled to a p-wave superconductor. This model is an extension of the Kitaev chain for a network triangular of finite-size with for three, four, and five sites. We find that the Majorana zero modes can be tuned through the coupling parameters of the device and the linear conductance show both the Majorana Bound States (MBS) in topological phase and in the general topological phase maximally robust. This more realistic model allows the detection of MBS through of the control of the parameters governing the electronic tunneling and can be helpful for relevant experiments. Keywords: Majorana Fermions, recursive Green’s function approach, Kitaev chain, class of electronic nanodevices, Quantum Dot, T-shaped, Qubit, Majorana Bound States (MBS).
190

Triphenylamine-based hole transport materials for perovskite solar cells

Fuentes Pineda, Rosinda January 2018 (has links)
The rapid development in perovskite solar cells (PSC) has generated a tremendous interest in the photovoltaic community. The power conversion efficiency (PCE) of these devices has increased from 3.8% in 2009 to a recent certified efficiency of over 20% which is mainly the product of the remarkable properties of the perovskite absorber material. One of the most important advances occurred with the replacement of the liquid electrolyte with a solid state hole conductor which enhanced PCE values and improved the device stability. Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)- 9,9'-spirobifluorene) is the most common hole transport material in perovskite solar cells. Nevertheless, the poor conductivity, low charge transport and expensive synthetic procedure and purification have limited its commercialisation. Triphenylamines (TPA) like Spiro-OMeTAD are commonly employed due to the easy oxidation of the nitrogen centre and good charge transport. Other triarylamines have similar properties to Spiro-OMeTAD but are easier to synthesise. The aim of this doctoral thesis is to investigate different types of hole transport materials in perovskite solar cells. Three different series of triphenylamine-based HTM were designed, synthesised, characterised and studied their function in perovskite solar cells. A series of five diacetylide-triphenylamine (DATPA) derivatives (Chapter 3) with different alkyl chain length in the para position was successfully synthesised through a five step synthesis procedure. A range of characterisation techniques was carried out on the molecules including; optical, electrochemical, thermal and computational methods. The results show that the new HTMs have desirable optical and electrochemical properties, with absorption in the UV, a reversible redox property and a suitable highest occupied molecular orbital (HOMO) energy level for hole transport. Perovskite solar cell device performances were studied and discussed in detail. This project studied the effect of varying the alkyl chain length on structurally similar triarylamine-based hole transport materials on their thermal, optical, electrochemical and charge transport properties as well as their molecular packing and solar cell parameters, thus providing insightful information on the design of hole transport materials in the future. The methoxy derivative showed the best semiconductive properties with the highest charge mobility, better interfacial charge transfer properties and highest PCE value (5.63%). The use of p-type semiconducting polymers are advantageous over small molecules because of their simple deposition, low cost and reproducibility. Styrenic triarylamines (Chapter 4) were prepared by the Hartwig-Buchwald coupling followed by their radical polymerization. All monomers and polymers were fully characterised through electrochemical, spectroscopic and computational techniques showing suitable HOMO energy levels and desirable optoelectrochemical properties. The properties and performance of these monomers and polymers as HTMs in perovskite solar cells were compared in terms of their structure. Despite the lower efficiencies, the polymers showed superior reproducibility on each of the device parameters in comparison with the monomers and spiro-OMeTAD. Finally, star-shaped structures combine the advantages of both small molecules, like well-defined structures and physical properties, and polymers such as good thermal stability. Two star-shaped triarylamine-based molecules (Chapter 5) were synthesised, fully characterised and their function as hole-transport materials in perovskite solar cells studied. These materials afford a PCE of 13.63% and high reproducibility and device stability. In total this work provided three series of triarylamine-based hole transport materials for perovskite solar cells application and enabled a comparison of the pros and cons of different design structures: small-molecule, polymeric and star-shaped.

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