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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.
751

The study of organofluorine analysis applied to totaloxidizable precursor (TOP) assay to understand perandpolyfluoroalkyl substances (PFASs)

Ho, Crystal January 2018 (has links)
Per- and polyfluoroalkyl substances (PFASs) are synthetic chemicals which are used in a wide range of applications such as aqueous film forming foam (AFFF) for firefighting, paint, coating and cosmetics. For almost a decade, PFASs have received worldwide attention because of the ubiquitous detection of PFAS in the environment and their bioaccumulative, persistent and give toxic effects on animals and humans. A number of study have shown many unknown organofluorine present in environmental samples. The total oxidizable precursor (TOP) method is an oxidation method to convert any precursor compounds of PFASs into measurable perfluorinated carboxylic acids (PFCAs) or sulfonic acids (PFSAs). The aims of this project are to evaluate if the use of total oxidizable precursor (TOP) assay may help improve the mass balance analysis between the quantifiable PFASs and extractable organofluorine in samples. In this study, three water samples: landfill leachate water, contaminated groundwater and adiluted Sthamex AFFF with tap water were undergone TOP assay to reveal the present of any unidentified precursor compounds. To obtain the extractable organofluorine and quantifiable PFAS levels in the samples, combustion ion chromatography (CIC) and liquid chromatography – tandem mass spectrometry (LC-MS/MS) were used, respectively. Results suggested the presence of unidentified precursor compounds in the samples with the aid of TOP assay reaction. Although after the oxidative conversion, a large portion of unidentified PFASs compounds were still present in the samples. The quantifiable PFASs in the samples were up to 7 % of the EOF; in other word, there were still around 93 % of unidentified compounds present in the samples. Further development of analytical method for characterization or identification of these unknown PFAS compounds is needed.
752

Optimization of energy storage use for solar applications

Ek, Ludvig, Ottosson, Tim January 2018 (has links)
Energy storage systems is very useful to use in solar panel systems to save money, but also tobe more environment-friendly. The project was given by the solar energy companyPerpetuum Automobile (PPAM) and the project is for their customer, the condominiumcompound Ekoxen. The task is to make a energy regulation for Ekoxen's energy storage sothey can save more money. The energy storage primary task is to shave the top-peaks of theconsumption for Ekoxen. Which means that the battery will supply the household instead forthe three-phase grid. This will make the electric bill for Ekoxen cheaper. Thesimulation/analysis of the energy regulation is done in a spreadsheet tool, where one partworks as a Time-of-Use program and the other work as a modbus feature. Time-of-Use is aweb-based program for PV systems with battery storage, where time-periods can be set toaffect the battery behavior. The modbus feature simulates a system where an algorithm can beimplemented. The results will show that the time-periods for charging the battery with theTime-of-Use program needs to be changed two times per year. One time for the summermonths and a second time for the rest of the months. The results will also show that themodbus feature is better on peak shaving than the time-of-use program.
753

PROPRIEDADES FÍSICAS DE UMA TOPOSSEQUÊNCIA ARGISSOLO-GLEISSOLO / PHYSICAL PROPERTIES OF A TOPOSEQUENCE GLEY-PODZOLIC

Braga, Fabiano de Vargas Arigony 31 March 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The soils of the Central Depression in Rio Grande do Sul consist mainly of mudstones, siltstones and sandstones. The region has dimensions ranging from 40 to 100 m at lower elevations (lowland) predominate Gley soils (shallow, poor drainage). In the plateau predominate Ultisols (deep to very deep and vary in color, as drainage level). The aim of this study was to evaluate the compressive behavior (carrying capacity and susceptibility to compaction) of the soil and influence of loads 25, 50, 100 and 200 kPa in the physical properties and water (CRA and air permeability). The sampling of soil for study was made in a private property located in Santa Maria. Trenches were dug to collect in two profiles located in the floodplain (Haplic Gley soil), two slopes (lower and upper) and one at the top, both Ultisol. In metal rings were collected soil samples with preserved structure for the uniaxial compression test on all horizons of the five different profiles, loads of 25, 50, 100 and 200 kPa in uniaxial press, then were only collected samples of soil surface horizons of the profiles for testing air permeability and water retention curve.. In both times the samples were equilibrated at a voltage of 10 kPa. Were carried out: sieve analysis, organic carbon, density, porosity, macro porosity, compressibility test, air permeability and water retention curve (WRC). The pre-consolidation pressure (σp) had a significant positive correlation with clay and negatively with sand, having no significant correlation with organic carbon (OC), degree of saturation (DS), voids (IV) and density (BD), the IC has had a significant negative correlation only with the Ds. Among the profiles, Gley Soils presented higher carrying capacity than the Argisols. Surface horizons had lower deformation compression curves compared to the subsurface, due to having larger soil density and smaller IV. The deeper horizons (BA, Bt1, Bt2 and Cg) showed higher σp than the surface horizons (A, Ap, A1, A2, B), by having greater amount of clay. The higher the load applied on the samples, higher soil density and porosity. The higher permeability was greater in profiles A, A1 and Ap under loads of 25 and 50 kPa, it produced no adverse effects on the structure. The application of higher loads in the sample changed the soil structure, retaining more water due to the increase of macro porosity. The Gley soils had a higher carrying capacity and are less susceptible to compaction than Argisols. Among Gley soil, profile 2 is less susceptible to compaction than a profile from the Ultisols and susceptibility to compaction of the profile 5 is lower than in profiles 3 and 4. The deeper horizons had higher pre-consolidation pressure (σp) and carrying capacity of the soil surface, because the greatest amount of clay. Loads of 25 and 50 kPa are lower than the values of pressure pre consolidation of horizons and the samples submitted showed no negative effects on the structure and had higher values of permeability. The application of loads 100 and 200 kPa, in the profiles 1.2 (floodplain), 4 (upper slope) and 5 (top) reduced the values of permeability, resulting from the change of the sample. The compacting process of the sample reduced macro porosity and increased total porosity by promoting greater water storage in the highest voltages applied. / Os solos da Depressão Central Gaúcha são constituidos porareia, silte e argila. A região tem cotas entre 40 à 100 m, nas mais baixas (várzea) predominam os Gleissolos e nas coxilhas predominam os Argissolos. O objetivo deste trabalho foi avaliar o comportamento compressivo (capacidade de suporte e susceptibilidade a compactação) do solo, e a influência de cargas 25, 50, 100 e 200kPa nas propriedades físicas e hídricas (curva de retenção de água (CRA) e permeabilidade ao ar (Ka)). As coletas de solo foram feitas em uma propriedade particular em Santa Maria, RS. Foram abertas trincheiras em dois perfis localizados na várzea (Gleissolos Háplicos), dois na encosta (inferior e superior) e um no topo, ambos Argissolo Vermelho. Foram coletadas amostras de solo com estrutura preservada em anéis metálicos para o teste de compressão uniaxial em todos os horizontes dos cinco diferentes perfis, após foram coletados somente amostras dos horizontes superficiais para os testes de Ka e CRA, após aplicadas as cargas de 25, 50, 100 e 200 kPa na prensa uniaxial. Nos dois momentos as amostras foram equilibradas à tensão de 10 kPa. Foram realizadas análise granulométrica, carbono orgânico, densidade, porosidade total, macroporosidade, microporosidade, teste de compressibilidade, Ka e CRA. A pressão de pré-consolidação (σp) teve correlação significativa positiva com a argila e negativa com a areia, não tendo correlação significativa com carbono orgânico (CO), grau de saturação (GS), índice de vazios (IV) e densidade do solo (Ds), o IC teve correlação significativa negativa somente com a Ds. Os Gleissolos apresentaram maior capacidade de suporte do que os Argissolos. Os horizontes superficiais tiveram menor deformação em relação aos subsuperficiais, devido a ter maior Ds e menor IV. Os horizontes mais profundos(BA, Bt1, Bt2 e Cg) apresentaram maior σp que os horizontes superficiais(A, Ap, A1, A2, AB), por terem maior quantidade de argila. Quanto maior a carga aplicada nas amostras, maior a densidade Ds e menos PT, a maior permeabilidade foi nos perfis A, A1 e Ap sob as cargas de 25 e 50 kPa, pois não produziram efeitos negativos na estrutura. A aplicação de maiores cargas na amostra mudou a estrutura do solo, retendo mais água em função do aumento de mircoporos. Os Gleissolos apresentaram maior capacidade de suporte e são menos suscetíveis à compactação do que os Argissolos. Os Gleissolos apresentaram maior capacidade de suporte e são menos suscetíveis à compactação do que os Argissolos. Dentre os Gleissolos, o perfil 2 apresentou menor susceptibilidade a compactação do que o perfil 1 e dentre os Argissolos, a susceptibilidade à compactação do perfil 5 é menor que nos perfis 3 e 4. Os horizontes mais profundos (BA, Bt1, Bt2 e Cg) apresentaram maior (σp) e capacidade de suporte que os horizontes superficiais (A, Ap, A1, A2 e AB) pois tem maior quantidade de argila. Após aplicação das cargas de 100 e 200 kPa, os perfis 1,2, 4 e 5 apresentaram menores valores de Ka, resultado da mudança de estrutura da amostra, diminuindo a macroporosidade e aumentando a microporosidade. A compactação da amostra reduziu a macroporosidade e a porosidade total promovendo um maior armazenamento de água nas maiores tensões aplicadas.
754

HODNOCENÍ UŽITKOVÝCH PARAMETRŮ U PLEMEN KAPRA OBECNÉHO A JEJICH KŘÍŽENCŮ / EVALUATE THE PERFORMANCE PARAMETERS OF THE BREEDS OF COMMON CARP AND ITS CROSSBREDS

KŘÍŽ, Michal January 2009 (has links)
The aim of the thesis was to evaluate the performance parameters of the breeds of common carp and its crossbreds by using the top-crossing. On the maternal position the Hungarian synthetic mirror carp line (HSM) was used. On this line, males of HSM, Telč mirror carp (TeL), Northern mirror carp (M72) and Amur mirror carp (AL) were crossed and a hybrid of Ropsha carp (ROP) and Tata carp (TAT) was used as their control group. Rearing of the tested groups was monitored from larval stage until their market size in ponds with a semi-intensive way of management in three localities (2 organisations). In the first year, each tested group was bred individually with internal control group of a different scaly covering phenotype in order to correct the influence of the environment on the weight achieved. In the second and the third year, all the groups were group-labelled and bred together in triplicate (three ponds) localities. In the individual stages of testing, the weight and the survival rate were recorded. Moreover, in the market size stage the biometric measurement and slaughtering value were evaluated. In the overall assessment of the results from all the localities carried out by the ANCOVA procedure, the highest weight at the K3 age was achieved by the hybrid HSM x AL (1413 {$\pm$} 31.5 g; Last square means {$\pm$} S.E.), whose weight was statistically comparable to the other hybrids (HSM x M72 a HSM x TeL). However, it was the only noticeably higher weight in comparison with the HSM (1257 {$\pm$} 31.5 g) with its ordinary heterosis effect of growth on the level of 12.4%. During the third year of testing, the survival ranged from 69.0 % in HSM x Tel to 73.4% in HSM x AL and the values were statistically comparable. The yield parameters (the proportion of the processed body, the proportion of filets with skin and the skinless ones) were similar in all the groups. In the previous periods of testing the results reflected the situation in the market size. As a result, it is concluded that preferably the hybrid HSM x AL could be exploitable in commercial breeding.
755

Životní způsob vrcholového managementu / The Top Manager Lifestyle

STAŇKOVÁ, Dana Maria January 2009 (has links)
No description available.
756

Design and implementation of a prototype home media system for an IP-based settop box / Design och implementation av en mediasystemprototyp för en IP-baserad set-top-box i hemmet

Johansson, Robert Bo January 2004 (has links)
This thesis covers design and implementation of a media system solution for home networks with personal computers and a set-top box. In a home there are effectively two independent media systems with the same purpose: the personal computer and the digital set-top box, with the purpose of delivering digital media in form of audio and video to the consumer. The goal of the thesis work was to implement a solution that bridges the gap between the two systems, so that the user, from the set-top box, can play back media that is actually stored on one or several personal computers. Our solution is based on UPnP technology, which is used for service discovery and control. The choice of UPnP is motivated by an evaluation of discovery protocols, which concludes that UPnP is the most suitable technology in this particular system. Also, an evaluation of suitable transport protocols was done. Here,HTTP was used. For the personal computer, a media server and a graphical user interface for configuring the media server were created. For the set-top box, a media client, and a graphical user interface for browsing the content of the media server, were created. In conclusion, the creation of the prototype was successful and the set-top box was able to playback media that had been shared by the PC on the network.
757

Formalisation of edit operations for structure editors

Holmquist, Johan January 2005 (has links)
Although several systems with structure editors have been built, no model exist to formally describe the edit operations used in such editors. This thesis introduces such a model --- a formalism to describe general structure edit operations for text oriented documents. The model allows free bottom-up editing for any tree-based structural document with a textual content. It can also handle attribute and erroneous structures. Some classes of common structures have been identified and structure editor specifications constructed for them, which can be used and combined in the creation of other structure editors.
758

A pesquisa em tomada de decisão estratégica no alto escalão: evolução e base intelectual do tema / The research on strategic decision making on upper echelons: evolution and intelectual basis of the theme

Bernardo Paraiso de Campos Serra 05 June 2013 (has links)
Esta dissertação tem como objetivo conhecer a produção acadêmica sobre tomada de decisão estratégica pelo alto escalão e entender quais as fundamentações teóricas basilares do tema. Metodologicamente, utilizou-se para este fim de pesquisa bibliométrica e bibliográfica de artigos publicados em periódicos internacionais, complementadas pela leitura analítica dos artigos encontrados na pesquisa. Pesquisou-se as principais palavras-chaves relacionadas ao tema na base de dados Web of Science - ISI Web Of Knowledge, utilizando-se de todos os periódicos e anos disponíveis. Procedeu-se então à leitura dos artigos, retirando aqueles que não refletissem o tema pesquisado, obtendo um total final de 277 artigos. Realizou-se uma análise bibliométrica sobre o conteúdo estudado nos artigos de tomada de decisão, identificando os trabalhos mais referenciados, as publicações mais relevantes, e os periódicos da amostra. Efetuou-se também, uma análise de co-citação, mostrando as relações conceituais entre os trabalhos que fundamentam o tema e identificando tendências dos estudos sobre o tema. Com a leitura analítica e a estruturação do conteúdo dos 277 artigos, expôs-se os objetivos, a base teórica utilizada, os objetos de estudo, a natureza e os resultados dos artigos. Foi, assim, possível identificar os principais clusters teóricos sobre o assunto. O primeiro cluster, aborda as características do Top Management Team (TMT) e como estas influenciam a tomada de decisão; o segundo, apresenta como fatores ambientais comprometem a tomada de decisão, juntamente com a exposição de modelos e processos de tomada de decisão; o terceiro, apresenta estudos sobre conflito e consenso na tomada de decisão. A discussão permitiu ilustrar o atual estado do tema e suas lacunas, apresentar sugestões para pesquisa futuras e propor a criação de um curso executivo sobre tomada de decisão. / This thesis aims to evaluate the academic production on strategic decision making in the upper echelons and understand what are the theoretical foundations of the subject. Methodologically, it was used for this purpose a bibliometric and bibliographic research of articles published in international journals, complemented by analytical reading of the articles found in the search. The main keywords related to the topic were searched in the database Web of Science - ISI Web Of Knowledge, using all available journals and years. We then read out the articles by removing those who did not reflect the theme researched, obtaining a final total of 277 items. A bibliometric analysis was conducted on the content studied in the articles of decision making, identifying the most referenced work, the most relevant publications, and journals of the sample. A co-citation analysis was also conducted, showing the conceptual relations between the work underlying the theme and identifying trends of the studies on the theme. With the analytical reading and the structuring of the content of the 277 articles, the objectives were exposed along with, the theoretical basis used, the objects of study, the nature and results of the articles. It was thus possible to identify the main theoretical clusters on the subject. The first cluster, discusses the characteristics of the Top Management Team (TMT) and how they influence decision making, the second shows how environmental factors compromise the decision making, along with the explanatory models and decision-making processes, the third presents studies conflict and consensus in decision making. The discussion permited the illustration of the current state of the subject and its gaps, making suggestions for future research and proposing the creation of an executive course on decision making.
759

Design and implementation of recording functionality for an IP-based set-top box / Design och implementation av inspelningsfunktionalitet för en IP-baserad set-top-box

Gusic, Aner January 2004 (has links)
This theses covers the design and implementation of recording functionality for a set-top box in a home network. An initial investigation is done and possibilities for extending the system to support specific features are presented. Digital TV is becoming more common each day, and soon it will be more widely used than todays analogue standard. At the same time the need for recording TV shows remains the same or is increasing, which is shown by the number of PVR solutions popping up on the market. The goal of this thesis work was to investigate the possibilities for extending an existing set-top box to support common PVR features and, if possible, to implement a prototype. This was supposed to be done in a home network environment with the set-top box as the digital media center. A satisfying solution, covering basic recording functionality is defined and implemented. The solution includes recording to a USB hard drive and to a PC on the local network. On top of this, a graphical user interface is built and some simple benchmarks show the performance of the set-top box with the new functionality.
760

Mobile learning in higher education : Students’ acceptance of mobile learning in three top Chinese universities

Zhu, Qiyao, Hu, Yan, Guo, Wentao January 2012 (has links)
Introduction: Along with the swift spread of 3G and wireless network, wireless technologies are applied in many areas, especially in education. The advent of mobile learning overcomes several limitations and barriers of traditional classroom education. As for higher education in China, mobile learning is in its infancy stage. Understanding end-users’ acceptance of mobile learning is crucial, because new technological advances cannot enhance performance if they are not accepted by end-users. This study focuses on three top Chinese universities and answers the following research questions: How do students perceive mobile devices as a learning tool incorporated in class and what are their attitudes towards mobile learning? What are the motivational factors that affect students’ acceptance of mobile learning? Purpose: The purpose of this study is to test the proposed Technology Acceptance Model (TAM) in explaining students’ acceptance in three top Chinese universities. The goal of this work is to enhance the understanding of user acceptance of incorporating learning into mobile device inside and outside classes. Method: A deductive, theory-testing approach was used in this study. Eleven hypotheses were built based on a literature review and on the proposed TAM model, and were tested using primary data and literature review. Primary data was gathered via semi-structured interviews and questionnaires. The data collected through the questionnaire was analysed by Structural Equation Modeling. Conclusion: Through testing the proposed model, the authors found that students are positive towards mobile learning but they do not have a strong willingness to adopt it. The proposed TAM model can improve the understanding of students’ motivation by suggesting what factors are the most important in enhancing students acceptance of mobile learning.

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