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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.
41

Utilização de biofiltro aerado submerso no tratamento de efluentes de curtume submetido a processo de pré-tratamentos físico-químico e anaeróbio /

Pereira, Eliane Leonora da Silva. January 2008 (has links)
Orientador: Tsunao Matsumoto / Banca: Dib Gebara / Banca: Maria Lucia Ribeiro / Resumo: Os efluentes de curtume caracterizam-se por possuírem elevadas concentrações de compostos tóxicos, tais como: cromo, amônia, sulfatos e compostos orgânicos de baixa biodegradabilidade, por isso o tratamento desses efluentes é extremamente difícil. O presente trabalho tem como objetivo comparar a eficiência de tratamento de efluentes de curtume de duas linhas experimentais, em escala piloto, compostas por: reator UASB simplificado em forma de "Y" seguido de um Biofiltro Aerado Submerso (BF) e somente um BF, operadas simultaneamente, recebendo o mesmo efluente pré-tratado físico-quimicamente, por meio de um decantador de coluna e um floculador de manta de lodo. As linhas experimentais foram montadas junto à estação de tratamento de efluentes do curtume Fuga Couros Jales Ltda., na cidade de Jales-SP. O monitoramento das linhas de tratamento foi dividido em 4 etapas operacionais distintas: 1aetapa, a partida do sistema experimental, 2a etapa, adição do coagulante sulfato de alumino ferroso, 3a etapa, aumento da taxa de aeração nos BFs e 4a etapa, aumento do TDH nos reatores. Em cada etapa, foram analisados os seguintes parâmetros: alcalinidade total, acidez volátil, cromo total, DBObruta, DQObruta, fósforo total, nitrato e nitrito, nitrogênio total e amoniacal, oxigênio dissolvido, pH, sólidos, sulfato, sulfeto e temperatura. A eficiência média de remoção de DQO e DBO, na linha 1, foi de 66% e 73%, respectivamente. Na linha 2, a eficiência média de remoção de DQO foi de 47% e de DBO foi de 49%. A baixa eficiência de remoção de DQO, nas duas linhas, é devido as elevadas concentrações de sulfato afluentes ao tratamento biológico, resultando numa baixa relação DQO/SO4 2-, cerca de 1,2. Apesar da eficiência de remoção de DBO, na linha 1, estar próxima da porcentagem mínima estipulada na legislação estadual, cerca de 80%, o efluente das duas ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The tanning effluents are characterized for its have high concentrations of toxicity compounds, such as: chromium, ammonia, sulfates and organic compound of low biodegradability, the treatment for those effluents is extremely hard. The present work has as objective compared the tanning effluents treatment efficiency of two lines experimental devices on pilot scale, composed for: line 1 - simplified UASB reactor on "Y" form following the Submerged Aerated Biofilter (BF) and line 2, only the BF reactor were operated simultaneously, receiving the same effluent pre-treated by physic-chemical devices, through a column settler and a sludge blanket flocculator. The experimental devices were installed in the tanning effluents treatment plant of the Fuga Couros Jales Ltd., at the Jales-SP city of. The treatment lines was monitoring on four different operational steps: 1st.step, start-up of the experimental system, 2nd step, addition of the coagulant ferrous aluminum sulfate in the pre-treatment devices, 3rd step, increase of the aeration rate in BFs and 4th step, increase the reactors HDT. On each step, the following parameters were analyzed: total alkalinity, volatile acidity, total chrome, BOD, COD, total phosphorous, nitrate and nitrite, total nitrogen and ammonia, dissolved oxygen, pH, solids, sulfate, sulfide and temperature. The COD and BOD removal efficiency average, in the line 1, was 66% and 73%, respectively. In the line 2, the removal efficiency average of the COD was 47% and the BOD was 49%. This low removal efficiency of COD, at two lines, is due the high sulfate inlet concentrations to the biological treatment, that resulting in a low COD/SO4 2- rate, about 1.2. In spite of the removal BOD efficiency, at line 1, reach the minimum state legislation requisite, about 80%, the effluent of the two treatment lines doesn't attempt the effluents discharges patterns, established by the environmental legislation. / Mestre
42

Modeling of Solid State Transformer for the FREEDM System Demonstration

January 2014 (has links)
abstract: The Solid State Transformer (SST) is an essential component in the FREEDM system. This research focuses on the modeling of the SST and the controller hardware in the loop (CHIL) implementation of the SST for the support of the FREEDM system demonstration. The energy based control strategy for a three-stage SST is analyzed and applied. A simplified average model of the three-stage SST that is suitable for simulation in real time digital simulator (RTDS) has been developed in this study. The model is also useful for general time-domain power system analysis and simulation. The proposed simplified av-erage model has been validated in MATLAB and PLECS. The accuracy of the model has been verified through comparison with the cycle-by-cycle average (CCA) model and de-tailed switching model. These models are also implemented in PSCAD, and a special strategy to implement the phase shift modulation has been proposed to enable the switching model simulation in PSCAD. The implementation of the CHIL test environment of the SST in RTDS is described in this report. The parameter setup of the model has been discussed in detail. One of the dif-ficulties is the choice of the damping factor, which is revealed in this paper. Also the grounding of the system has large impact on the RTDS simulation. Another problem is that the performance of the system is highly dependent on the switch parameters such as voltage and current ratings. Finally, the functionalities of the SST have been realized on the platform. The distributed energy storage interface power injection and reverse power flow have been validated. Some limitations are noticed and discussed through the simulation on RTDS. / Dissertation/Thesis / M.S. Electrical Engineering 2014
43

Análise numérica de pilares de aço isolados e inseridos em paredes em situação de incêndio / Numerical analysis of isolated and embedded on walls steel columns under fire situation

Yagho de Souza Simões 10 April 2018 (has links)
Em um incêndio, pilares de aço inseridos em paredes apresentam uma resposta termoestrutural diferente daqueles isolados, de modo que a compartimentação oferece um aumento de sua resistência ao fogo. Poucos estudos foram desenvolvidos até o presente momento para avaliar o desempenho de pilares em contato com paredes, sendo que aqueles já realizados apresentaram respostas que ainda deixam dúvidas sobre esses elementos. Diante disso, este trabalho propõe analisar, em contexto numérico, o comportamento de pilares de aço isolados e inseridos em paredes sujeitos à ação térmica, a partir do uso do código computacional ABAQUS versão 6.14. A modelagem termoestrutural, considerando a parede somente como elemento de compartimentação, promoveu resultados pouco consistentes, o que leva a concluir que a alvenaria influencia na resposta estrutural de pilares em situação de incêndio. Por essa razão, ao inserir molas que controlam o deslocamento axial das paredes na modelagem numérica, os resultados alcançados passaram a ser mais representativos. Análises complementares a respeito da influência do fator de carga e do nível de rigidez axial e rotacional na resistência ao fogo dos pilares também foram realizadas. Para todos os modelos, constatou-se a influência negativa do fator de carga quando aumentado. Quanto à restrição axial, foi verificado que sua presença possui maior influência na resistência ao fogo em comparação com sua intensidade, uma vez que a elevação desse parâmetro não afetou o tempo crítico dos pilares, para a maior parte dos casos analisados. Em relação à rigidez rotacional, ela se mostrou favorável para a resistência ao fogo. Além do mais, a pesquisa contou com uma avaliação do método simplificado da ABNT NBR 14323:2013 para cálculo da evolução da temperatura em perfis de aço. Concluiu-se que ele apresenta melhores resultados para os pilares com aquecimento uniforme na seção transversal. Por essa razão, foi proposta uma nova metodologia de cálculo de temperatura para pilares em contato com paredes, validada por meio de testes numéricos. / In a fire situation, steel columns embedded on walls demonstrate a different thermo- structural response from those isolated, so that the subdivision offers an increase of its fire resistance. Few studies have been developed in order to evaluate the performance of columns in contact with walls, and those already performed showed results that still leave doubts about these elements. Therefore, this work proposes to analyze, in a numerical context, the behavior of isolated and embedded on walls steel columns in fire using the software ABAQUS 6.14 as a modeling tool. The thermo-structural modeling, considering the wall only as a compartmentation element, has presented poor results, which leads to the conclusion that the masonry has influence on the structural response of columns subjected to fire situation. For this reason, when inserting springs in order to control the axial displacement of the walls in numerical modeling, the obtained results were satisfactory. Further analyzes in respect of the load factor influence and the level of axial and rotational stiffness on the fire resistance of columns were also performed. For all the models, it was verified a negative influence of the load factor when increased. However, when it comes to the axial restriction, it was verified that its presence had more influence in the fire resistance of the structural element despite of its intensity, once the increase of this parameter did not affect the critical time of the columns, for most cases analyzed. In respect to rotational stiffness, it was proven favorable to the fire resistance. In addition, this research employed the simplified method presented in the ABNT NBR 14323: 2013 to calculate the temperature evolution in steel profiles. It was concluded that it presents good results only for the columns with uniform heating in the cross section. For this reason, a new methodology to calculate the temperature of columns in contact with wall was proposed, validated by numerical tests.
44

Comparison of Authentic and Simplified Texts : A case study of Wuthering Heights

Öhqvist, Åsa January 2016 (has links)
The aim of this essay is to explore in what way Graded Readers are different from authentic texts against the background of English as a Second Language (ESL) and the use of authentic and simplified text in ESL teaching. The material used for this purpose is the authentic text of Wuthering Heights by Emily Brontë and two upper-intermediate Graded Readers from two different publishers. The study uses the software readability-score and manual analysis to examine the texts with regards to lexical choice, language structure and story. The study showed that the Graded Readers are simplified in all aspects studied. Moreover, the Graded Readers differ from each other as well, most notably in the style of the text due to sentence structure and story simplification. This could imply that different authors of Graded Readers adopt different styles when simplifying text and that the grading levels are not comparable between different publishers. / <p>Engelska</p>
45

Advantages and disadvantages with Simplified Technical English : to be used in technical documentation by Swedish export companies

Disborg, Karin January 2007 (has links)
Understanding technical documentation is of vital importance, since instructions and descriptions are given about how technical products are used, maintained and repaired. Because of the increased economic globalization, more and more documentation is both written in English by non-native English writers, and delivered to non-native English readers. More and more documentation is also translated by means of computerized aids. In order to improve comprehension and translatability of technical documentation, controlled languages are created. Controlled languages are subsets of ordinary languages, but with restricted vocabularies and writing rules. The aim of this report is to discuss the advantages and disadvantages for Swedish export companies to use Simplified Technical English (STE), which is a controlled language, for their technical documentation. In this work technical writers are asked about their opinions of STE. Additionally, technical texts written in traditional English are compared with versions written in STE, in order to find out whether texts written in a controlled language are easier to read or not. Within the comparison, the differences between the versions are discussed and a readability measurement is done. The measurement showed that readability in technical documentation is improved by using STE. The writers’ opinions are illuminated in three areas, which are: higher documentation quality, reduced translation costs and reduced production costs.
46

Assessing uplift displacement of buried geotechnical structures in liquefied ground during earthquakes / 液状化地盤中における埋設構造物の浮き上がり量の評価に関する研究

Kang, GiChun 23 March 2010 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15340号 / 工博第3219号 / 新制||工||1485(附属図書館) / 27818 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 井合 進, 教授 岡 二三生, 教授 木村 亮 / 学位規則第4条第1項該当
47

The impact of fire development on design resistance of structures

Eberius, Catrin, Fjällström, Kristin January 2017 (has links)
The current design methods used to determine fire progression and temperature-time development in fire compartments today are being questioned to not give accurate results in large and complex enclosures (larger than 500 m2). The established design methods proposed by Eurocode and used by fire safety engineers today are primarily the standard temperature-time curve and the parametric temperature-time curves. The parametric temperature-time curves are based on the heat and mass balance equations and both methods assume homogenous temperatures and uniform burning. These assumptions are being questioned for use in large enclosures such as open-plan compartments and compartments with multiple floors connected which are typically modern and common building types in today’s society. Today there are no established design methods developed to determine fire progression in large enclosures, but the Improved Travelling Fire Method (iTFM) and the New MT model II are new, alternative design methods which are prospects to become established engineering tools in the future. The iTFM is developed at the University of Edinburgh for travelling fires in large size compartments and the New MT model II is developed by RISE, Research Institutes of Sweden, for large tunnel fires. These two new design methods have been investigated and compared to established methods in a case study. Also localised fires from Eurocode with proposed interpretations by Ulf Wickström has been investigated and compared to the standard temperature-time curve and the parametric temperature-time curves. The new interpretation suggests that the given heat flux boundary conditions in Eurocode are interpreted as adiabatic surface temperatures based on given emissivities and convection heat transfer coefficients according to Eurocode. Through a case study the different methods were compared throughout reference buildings with constant material properties and fire loads, but with varying floor area and height. The result focused on if the new methods have more bearing on reality than the standard fire curve and the parametric temperature-time curves methods when determining fire progression and temperature-time development. Desired benefits with the new methods are to better predict and describe fire development in large enclosures. The referenceIIIbuildings were considered as occupancy class 2 (Vk2) and Br2 buildings with a load bearing fire resistance capacity demand of 30 minutes. This report is an early stage in the process of developing new fire models to improve the fire designing process when working with large compartments. The aim with the new, alternative methods and localised fires with proposed interpretation is to enable them to become engineering tools used by fire safety engineers in the future to create a more efficient and adapted design process. The results differ significantly depending on used method and reference building. The maximum temperatures conducted by the iTFM are in general higher than the standard fire curve and the parametric temperature-time curves. When applying the method to the reference building with high ceiling height and low spread rate the resulting temperatures were lower than the standard fire curve. The fire progression of the New MT model II is highly dependent on opening factor and time until temperature increase starts. In comparison to the parametric fire curves with the same opening factors the New MT model II resulted in considerably faster temperature development and higher temperatures. Localised fires with the new proposed interpretations resulted in adiabatic surface temperatures which were compared to the standard temperature-time curve after 30 minutes of fire and the maximum temperature of the parametric temperature-time curves. The comparison resulted in slightly lower temperatures for the localised fires with the new proposed interpretations compared to the standard temperature-time curve and similar temperatures compared to the parametric temperature-time curves in the case study. The results of the iTFM and the New MT model II differs significantly depending on physical parameters used in the calculation processes. The models are customizable and vary depending on fire scenarios and compartments and could possibly be future alternative methods when designing for fires in large compartments. Further studies and development together with real fire tests would provide the models with better accuracy and continuity. Localised fires with proposed new interpretations are a future prospect to become a future standard method for determination of maximum temperature of member surfaces in fire safety design.
48

Lateral Torsional Buckling of Wooden Beams with Mid-Span Lateral Bracing

Hu, Ye January 2016 (has links)
An analytical and numerical investigation is conducted for the lateral torsional buckling analysis of wooden beam with a mid-span lateral brace subjected to symmetrically distributed loading. Two models are developed; one for the case of a rigid brace and another one for the case of a flexible brace. The analytical solutions are based on the principle of stationary potential energy and a Fourier expansion of the buckling displacement fields and bending moments. The validity of both models are verified against 3D finite element analyses in ABAQUS. Where applicable, verifications were also conducted against available solutions from previous studies. Parametric studies were conducted to investigate the effect of geometric and material parameters on the critical moments. The results indicate the presence of two separate groups of potential buckling modes, symmetric and anti-symmetric, with fundamentally different behavioural characteristics. The governing buckling mode is shown to depend on the bracing height, load height and lateral brace stiffness. The study shows that beyond a certain threshold bracing height, the critical moment is governed by the antisymmetric mode of buckling. Also, above a certain optimum bracing stiffness, no increase is observed in the critical moments. The models developed are used to construct a comprehensive database of parametric investigations which are then employed for developing simplified equations for determining the threshold heights, associated critical moments, and optimum stiffness.
49

Ukončování tranzitu při dovozu zboží do ČR / Termination of customs transit for imports to the Czech Republic

Pospíchalová, Veronika January 2014 (has links)
The Master's Thesis is focused on customs transit, especially Common and Community transit. Prerequisites, process and termination are analysed, including simplified procedures. The Master's Thesis puts customs transit within a broader context of international trade and customs procedures, states relevant legislation, underlines risks related to their formulation and proposes solutions. The practical application is written from the point of view of Siemens, for which compliance with rules and regulations is essential and therefore is a good example to illustrate how to resolve the inconsistency of legislation with the business practice.
50

Combined Heuristic and Statistical Methodologies applied to Maneuver Detection in the SST Observation Correlation Process

Mukundan, Arvind January 2020 (has links)
In this project, an algorithm has been proposed to detect a satellite’s maneuver by comparingthe orbital elements observed from the two line element data and the orbital elements propagatedwith the help of Simplified perturbations models. A set of TLE data for an object orbiting Earthcontains a specific set of orbital elements. Simplified perturbation are utilized to propagate theorbital velocity and position vector of the same object. By comparing the results obtained fromboth the methods, the maneuvers of a satellite are detected. This project outlines the workingmethodology and the implementation of the algorithm developed to detect the maneuvers. Thefunctioning of the technique is assessed with reference to two case studies for which the maneuverhistory is available by following the approach employed by Kelecy et al. (2007). The same methodis implemented to detect the orbit controlling maneuvers as well as the fine control maneuvers. Theresults derived from the analysis indicate that the maneuvers which has the magnitude of even aslow as cm/s has been detected when the detection parameters are calibrated properly.

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