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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.
1

Variações termicas ocorridas na fotoativação de composito em função da comparação de metodos de avaliação / Comparison of different thermal variation analysis methods during composite light-curing

Loureiro, Flávia Helen Furtado 02 September 2007 (has links)
Orientador: Simonides Consani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-08T05:29:08Z (GMT). No. of bitstreams: 1 Loureiro_FlaviaHelenFurtado_M.pdf: 641905 bytes, checksum: 2615b8335b9cf2d7b6a766b05792ef4e (MD5) Previous issue date: 2007 / Resumo: O estudo avaliou o efeito de métodos de avaliação sobre as variações térmicas, em função de diferentes tipos de fotoativação do compósito Filtek Z250. Para o método de avaliação pelo dente foram utilizados 50 incisivos bovinos hígidos, nos quais foram feitos preparos cavitários (2x2x2mm) padronizados a 13mm da junção amelo-cementária. Os dentes foram separados aleatoriamente em 5 grupos (n=10), de acordo com o tipo de fotoativação: 1- luz halógena contínua (700 mW/cm2 por 20s); 2- luz halógena com dupla intensidade (inicial de 100 mW/cm2 por 5s obtida com espaçador, seguido de 700 mW/cm2 por 15s, totalizando 20s); 3- luz halógena intermitente (2s de ativação com 700 mW/cm2 seguido do mesmo tempo pela ausência de luz, totalizando 40s); 4- luz emitida por diodo (400 mW/cm2 por 20s); 5- luz emitida por arco de plasma de xenônio (1450 mW/cm2 por 10s). No método de avaliação pela matriz, a resina composta foi inserida num molde cúbico de silicone (2x2x2mm) apoiado numa base de resina acrílica para servir como guia do termopar. Um disco de dentina (1mm) foi colocado entre o termopar e a resina composta para simular a dentina remanescente do preparo cavitário do método de avaliação pelo dente. O protocolo experimental de fotoativação para o método de avaliação pela matriz foi similar ao método de avaliação pelo dente. As restaurações de ambos os métodos foram realizadas em ambiente controlado (37oC e 40±10% UR) e as temperaturas registradas com termômetro digital acoplado ao termopar tipo-K introduzido no canal radicular, de maneira que ficasse, no método dente, em contato com a dentina da câmara pulpar, correspondente à parede axial do preparo e no método matriz, em contato com o disco de dentina. Os dados foram submetidos à analise de variância e ao teste de Tukey em nível de 5% de probabilidade. A média da variação de temperatura registrada pela técnica da matriz (2.56oC) foi maior e com diferença estatisticamente significante quando comparada à média registrada na técnica do dente (1.17 oC), independente dos demais fatores. Houve diferença estatística significativa entre os fotoativadores quando comparados em cada método de avaliação e em todos os tipos de fotoativação quando os métodos de avaliação foram comparados entre si / Abstract: This study evaluated the effect of different methods of thermal evaluation using Filtek Z250 composite resin with different methods of photoativation. In the method of evaluation with tooth it was used 50 incisors where was prepared standardized cavities (2x2x2mm) 13 mm far from amelo-cementary junction. The teeth were randomly assigned into 5 groups (n=10), according to each light-curing method: 1- continue halogen light ( 700mW/cm2 per 20s); 2- halogen light with a soft-start mode (initial intensity of 100mW/cm2 per 5s obtained with a spacer and 700 mW/cm2 per 15s, totaling 20s); 3-intermittent halogen light (2s at 700 mW/cm2, followed by the same time of light absence, totaling 40s); 4- LED (400 mW/cm2 per 20s); PAC (1450 mW/cm2 per 10s). In the method of evaluation with matrix the resin composites were applied into a cubic elastomer mold (2x2x2mm). This mold was positioned under the acrylic resin base that guide the acess of thermocouple. Between the thermocouple and the composite, a 1.0mm dentine disc was positioned to simulated the remaining dentin of the method of evaluation with tooth. The same experimental protocol of photoativation was used for both methods. All experiments were carried out in a controlled environment (37 degree centigrates and 40±10% relative humidity). The variations of temperature(degree centigrates) were obtained using a digital thermometer attached to a type-k thermocouple, which was inserted into the root canal and in contact to the dentine of the pulp chamber (correspondent to the axial wall of the cavity) or in the matrix in contact with the dentine discs. The data were submitted to a two-way ANOVA and the means were compared by the Tukey's test (5%). The variation of temperature with the matrix technique (2.56 degrees centigrates) was higher and with significant different from the tooth technique (1.17 degrees centigrates), independent of the others factors. There was statistical difference among light cure units inside the same evaluation method and when the methods were compared. / Mestrado / Mestre em Materiais Dentários
2

Different techniques to evaluate a liquid rumen protected methionine source for dairy cows

Bester, Zeno 23 May 2013 (has links)
Rumen protected methionine has been used in an effort to improve the amino acid composition of metabolisable protein since the early 1960’s. The positive response in dairy cows in terms of milk protein composition and milk production, especially during early lactation has been well documented. Rumen protected methionine supplementation contributes to improving the protein efficiency of the dairy cow which improves the overall productivity of the dairy enterprise. Recently a locally developed liquid rumen protected methionine prototype became available. In our study this product was evaluated through a series of experiments in conjunction with two standard, well known methionnine sources, Smartamine ™ M and unprotected DL-methionine that provided a reference to the relative bioavailability of the liquid rumen protected methionine. In the first of the two studies the effect of methionine supplementation on milk yield, milk composition as well as milk protein composition was evaluated through the milk composition technique. The ability of the liquid rumen protected methionine to elevate blood plasma methionine levels was also evaluated through the blood plasma technique after oral dosing and post ruminal infusion of methionine. The liquid rumen protected methionine prototype induced no response in either milk yield or milk composition. Results suggested that the prototype is either not adequately protected against rumen degradation or it is not available for absorption in the small intestine. The inability of the liquid rumen protected methionine prototype to elevate blood plasma methionine after post ruminal infusion further proved that the product is not available for absorption at this site either. In the event that the product’s mode of action or method of protection caused it not to be detected as pure methionine in the blood, an effect on milk yield would have been expected which was not the case. This product proved to have a very low or no bioavailability in comparison to the well researched and proven Smartamine ™ M. / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Animal and Wildlife Sciences / unrestricted
3

Development of a capital investment framework for a gold mine / M. Clasen

Clasen, Mari January 2011 (has links)
This study was done against the backdrop that executives should carefully consider all the options to manage difficult periods before letting employees go, especially if they are going to rehire employees shortly after the economic recovery. Therefore, the study investigated whether investing in operational development of a plant can be used to increase feasibility, rather than to make across–the–board labour cuts. Two South African mining companies were chosen for this study. They are two investment centres at AngloGold Ashanti, Mine X Ltd. and Mine Z Ltd. The investigating project was done at Mine X to extract gold from the neighbouring Mine Z. Mine X will have access to the minerals 40 years in advance of Mine Z due to insufficient essential infrastructure at Mine Z. The life–time of the project is 18 years (estimated). The main objective of this study is to investigate the feasibility, from Mine X’s point of view, with a deepening project including Mine Z. The most significant aspect will be to determine which investment timeframe decision will gain Mine X a feasible position in terms of economic growth. This will be achieved by the following secondary objectives in making a capital investment decision: 1. To describe the nature and significance of investment decision making. 2. To recognise appropriate capital investment evaluation techniques in conjunction with sensitivity analysis. 3. To apply the techniques and sensitivity analysis in order to make a decision of a possible, feasible investment opportunity at Mine X. 4. To develop a framework to identify the project’s components and associate and access difficulties for Mine X‘s project lifecycle. The feasibility study undertakes multiple scenarios and provides recommendations and a final report, based on the scenario that is the most viable. The following techniques which were identified were used to analyse the feasibility of the project: Net present value, internal rate of return and payback period. All these above techniques will be analysed in three different scenarios, namely: 1. Mine X will stay with its current operations without any new projects. 2. The development project will begin immediately. 3. A six–month delay in development of the project. The study found that the net present value was positive, the internal rate of return was more than the discount rate and the payback period was shorter than the project’s life–time regarding to all three above–mentioned scenarios. The highest net present value is calculated in case the project starts immediately. Both the internal rate of return and the payback period indicated that a six month delay in the project is the most viable. After considering all the facts, the study concluded due to the highest net present value the best feasible recommendation would be to start the project immediately. The value of this study is that it is the first study to investigate the relationship between the viability to delay or to start the investment project immediately in the South African mining industry. This study is also unique, since it takes into account how mining industries world–wide can achieve long–term success through development projects without losing key players, due to impulsive short–term downsizing decisions. / Thesis (M.Com. (Management Accountancy))--North-West University, Potchefstroom Campus, 2012.
4

Development of a capital investment framework for a gold mine / M. Clasen

Clasen, Mari January 2011 (has links)
This study was done against the backdrop that executives should carefully consider all the options to manage difficult periods before letting employees go, especially if they are going to rehire employees shortly after the economic recovery. Therefore, the study investigated whether investing in operational development of a plant can be used to increase feasibility, rather than to make across–the–board labour cuts. Two South African mining companies were chosen for this study. They are two investment centres at AngloGold Ashanti, Mine X Ltd. and Mine Z Ltd. The investigating project was done at Mine X to extract gold from the neighbouring Mine Z. Mine X will have access to the minerals 40 years in advance of Mine Z due to insufficient essential infrastructure at Mine Z. The life–time of the project is 18 years (estimated). The main objective of this study is to investigate the feasibility, from Mine X’s point of view, with a deepening project including Mine Z. The most significant aspect will be to determine which investment timeframe decision will gain Mine X a feasible position in terms of economic growth. This will be achieved by the following secondary objectives in making a capital investment decision: 1. To describe the nature and significance of investment decision making. 2. To recognise appropriate capital investment evaluation techniques in conjunction with sensitivity analysis. 3. To apply the techniques and sensitivity analysis in order to make a decision of a possible, feasible investment opportunity at Mine X. 4. To develop a framework to identify the project’s components and associate and access difficulties for Mine X‘s project lifecycle. The feasibility study undertakes multiple scenarios and provides recommendations and a final report, based on the scenario that is the most viable. The following techniques which were identified were used to analyse the feasibility of the project: Net present value, internal rate of return and payback period. All these above techniques will be analysed in three different scenarios, namely: 1. Mine X will stay with its current operations without any new projects. 2. The development project will begin immediately. 3. A six–month delay in development of the project. The study found that the net present value was positive, the internal rate of return was more than the discount rate and the payback period was shorter than the project’s life–time regarding to all three above–mentioned scenarios. The highest net present value is calculated in case the project starts immediately. Both the internal rate of return and the payback period indicated that a six month delay in the project is the most viable. After considering all the facts, the study concluded due to the highest net present value the best feasible recommendation would be to start the project immediately. The value of this study is that it is the first study to investigate the relationship between the viability to delay or to start the investment project immediately in the South African mining industry. This study is also unique, since it takes into account how mining industries world–wide can achieve long–term success through development projects without losing key players, due to impulsive short–term downsizing decisions. / Thesis (M.Com. (Management Accountancy))--North-West University, Potchefstroom Campus, 2012.
5

A software component quality framework

ALVARO, Alexandre 31 January 2009 (has links)
Made available in DSpace on 2014-06-12T15:49:28Z (GMT). No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Um grande desafio da Engenharia de Software Baseada em Componentes (ESBC) é a qualidade dos componentes utilizados em um sistema. A confiabilidade de um sistema baseado em componentes depende da confiabilidade dos componentes dos quais ele é composto. Na ESBC, a busca, seleção e avaliação de componentes de software é considerado um ponto chave para o efetivo desenvolvimento de sistemas baseado em componentes. Até agora a indústria de software tem se concentrado nos aspectos funcionais dos componentes de software, deixando de lado uma das tarefas mais árduas, que é a avaliação de sua qualidade. Se a garantia de qualidade de componentes desenvolvidos in-house é uma tarefa custosa, a garantia da qualidade utilizando componentes desenvolvidos externamente os quais frequentemente não se tem acesso ao código fonte e documentação detalhada se torna um desafio ainda maior. Assim, esta Tese introduz um Framework de Qualidade de Componentes de Software, baseado em módulos bem definidos que se complementam a fim de garantir a qualidade dos componentes de software. Por fim, um estudo experimental foi desenvolvido e executado de modo que se possa analisar a viabilidade do framework proposto
6

An empirical study of capital budgeting evaluation techniques used in firms in the Nelson Mandela Metropole

Bester, Lizel January 2006 (has links)
The first research objective of this dissertation is an empirical study of the capital budgeting process to determine what capital budgeting evaluation techniques are used by firms in the Nelson Mandela Metropole. The second research objective of this dissertation is how the size of the firm impacts on the type of capital budgeting evaluation techniques used. The size of the firm is measured by magnitude of turnover, assets and the number of employees.
7

Estudo sobre a variação dos parâmetros do Tree Load Balancing Algorithm / Study about the variation of the Tree Load Balancing Algorithm parameters

Raphaloski, Evandro 21 February 2006 (has links)
Em um sistema localmente distribuído, quando diversas tarefas são aleatoriamente submetidas aos computadores de uma determinada rede, onde alguns ficam sobrecarregados e outros permaneçam ociosos, algoritmos de balanceamento de carga podem ser utilizados para homogeneizar e otimizar a alocação de recursos e, conseqüentemente, aumentar o desempenho computacional. Com a evolução dos sistemas distribuídos, houve a necessidade de aprimoramento desses algoritmos, a fim de suportarem sistemas distribuídos altamente escaláveis e possibilitarem o gerenciamento de ambientes heterogêneos. Visando suprir essas necessidades, recentemente foi proposto um algoritmo de balanceamento de carga denominado Tree Load Balancing Algorithm (TLBA). Para avaliar esse algoritmo foram desenvolvidos um simulador e um protótipo. Com as simulações foram comprovados seus benefícios para ambientes distribuídos heterogêneos altamente escaláveis e com o protótipo esses resultados foram validados. Este trabalho apresenta a implementação de um novo simulador, que possibilitou um estudo mais abrangente dos parâmetros de balanceamento de carga do TLBA, com base em amostras estatisticamente geradas e uma maior fidelidade em suas políticas de balanceamento. Suas novas características são simulação em tempo real, visualização da árvore lógica de acordo com as capacidades computacionais relativas, resultados em tabelas, gráficos gerados pelo simulador e estudos aplicados aos diferentes tipos de escalonamento e sistemas / In locally distributed systems, when plenty of tasks are randomically submitted to network computers where certain computers may be heavily loaded, while others lightly loaded, load balancing algorithms may be used on to homogenize and optimize the resources allocation, and hence improve the computer performance. Later on, the distributed systems evolution made necessary the upgrading of these algorithms in order to support the highly scalable distributed systems and handle with the management of the heterogeneous environments. To supply these needs, a new load balancing algorithm called Tree Load Balancing Algorithm (TLBA) has been recently proposed. The evaluation of this algorithm has been done by a simulator and a prototype which were developed for this purpose. The simulations have proved its benefits in highly scalable heterogeneous distributed environments, and with the prototype the results were validated. This work presents the implementation of a new simulator which allows detailed studies of the TLBA parameters, based on the statistically generated samples, and a higher fidelity on the implementation of its load balancing policies. Its new features are the real time simulations, visualization of the logical tree according to computers’ relative capacities, results in tables, graphics generated by the simulator and studies applied to the different types of scheduling and systems
8

Estudo sobre a variação dos parâmetros do Tree Load Balancing Algorithm / Study about the variation of the Tree Load Balancing Algorithm parameters

Evandro Raphaloski 21 February 2006 (has links)
Em um sistema localmente distribuído, quando diversas tarefas são aleatoriamente submetidas aos computadores de uma determinada rede, onde alguns ficam sobrecarregados e outros permaneçam ociosos, algoritmos de balanceamento de carga podem ser utilizados para homogeneizar e otimizar a alocação de recursos e, conseqüentemente, aumentar o desempenho computacional. Com a evolução dos sistemas distribuídos, houve a necessidade de aprimoramento desses algoritmos, a fim de suportarem sistemas distribuídos altamente escaláveis e possibilitarem o gerenciamento de ambientes heterogêneos. Visando suprir essas necessidades, recentemente foi proposto um algoritmo de balanceamento de carga denominado Tree Load Balancing Algorithm (TLBA). Para avaliar esse algoritmo foram desenvolvidos um simulador e um protótipo. Com as simulações foram comprovados seus benefícios para ambientes distribuídos heterogêneos altamente escaláveis e com o protótipo esses resultados foram validados. Este trabalho apresenta a implementação de um novo simulador, que possibilitou um estudo mais abrangente dos parâmetros de balanceamento de carga do TLBA, com base em amostras estatisticamente geradas e uma maior fidelidade em suas políticas de balanceamento. Suas novas características são simulação em tempo real, visualização da árvore lógica de acordo com as capacidades computacionais relativas, resultados em tabelas, gráficos gerados pelo simulador e estudos aplicados aos diferentes tipos de escalonamento e sistemas / In locally distributed systems, when plenty of tasks are randomically submitted to network computers where certain computers may be heavily loaded, while others lightly loaded, load balancing algorithms may be used on to homogenize and optimize the resources allocation, and hence improve the computer performance. Later on, the distributed systems evolution made necessary the upgrading of these algorithms in order to support the highly scalable distributed systems and handle with the management of the heterogeneous environments. To supply these needs, a new load balancing algorithm called Tree Load Balancing Algorithm (TLBA) has been recently proposed. The evaluation of this algorithm has been done by a simulator and a prototype which were developed for this purpose. The simulations have proved its benefits in highly scalable heterogeneous distributed environments, and with the prototype the results were validated. This work presents the implementation of a new simulator which allows detailed studies of the TLBA parameters, based on the statistically generated samples, and a higher fidelity on the implementation of its load balancing policies. Its new features are the real time simulations, visualization of the logical tree according to computers’ relative capacities, results in tables, graphics generated by the simulator and studies applied to the different types of scheduling and systems
9

Environmental Determinants and Choice of Project Evaluation Techniques in US and UK Firms

Smolarski, Jan M. (Jan Mietek) 05 1900 (has links)
The purpose of this dissertation is to develop a theory that helps explain the conditions under which firms select certain project evaluation techniques. This study uses contingency theory to analyze the impact of environmental uncertainty on the choice of project evaluation techniques. In addition to a direct measure of uncertainty, several dimensions of uncertainty are included in this study. These dimensions of uncertainty include control structure, method of financing, foreign assets, method of growth, and product domination. This study also analyzes the use of project evaluation, management science and risk management techniques in US firms over time and in UK firms over time in order to compare to prior research. A comparison of firms in the two countries are also provided. The primary method of data collection was a survey instrument. Data were also collected from annual reports and various other public sources. The variables that appear significant in the choice of project evaluation technique in US firms are environmental uncertainty, control structure, method of financing, foreign assets, and product domination. The variable that appear significant in the choice of project evaluation technique in UK firms is method of financing. US firms favor discounted cash flow techniques although this study detected a slight decrease over time. UK firms continue to use non-discounted cash flow techniques, although the use of discounted cash flow techniques is widespread. There are significant differences between US and UK firms. US firms tend to use discounted cash flow techniques to a greater extent than UK firms. This research makes a significant contribution in attempting to develop a theory explaining the use of project evaluation techniques in firms in the US and UK. In addition, several other developments relating to project evaluation, management science and risk management are discussed. The results of this study can be used by managers in refining and improving their existing project evaluation processes.
10

Définition et test d'un outil d'aide à l'évaluation de systèmes à architecture à base d'agent, par approche à base de connaissances.

Charfi, Selem 15 February 2013 (has links)
Ce mémoire contribue à la thématique de l'évaluation des interfaces utilisateur. Il se base sur deux contributions pour l'évaluation de ces interfaces. La première consiste en un Framework se basant sur trois différentes techniques d'évaluation (le mouchard électronique, le questionnaire et l'inspection des règles ergonomiques). La seconde consiste en deux ensembles de composants graphiques pour la composition d'interfaces graphiques avec les environnements de développement intégral du type WYSIWYG. Le premier ensemble vise à inspecter la présentation statique de l'interface lors de la conception de cette dernière. Cette inspection s'effectue localement par le composant graphique lui-même par rapport à un ensemble de règles ergonomiques. Le second ensemble consiste à l'évaluation de l'interface utilisateur en analysant l'interaction entre l'utilisateur et l'interface. Cet ensemble de composants opère avec un mouchard dédié à cet usage. Une évaluation de ces deux contributions ainsi que des perspectives de recherche concluront ce présent mémoire. / This thesis report is a contribution to the user interface evaluation theme. Our thesis is based mainly on two contributions for user interface evaluation. The first one consists of a Framework dedicated for user interface evaluation. It is based on three evaluation techniques (the electronic informer, the questionnaire and the ergonomic inspection). The second consists of two sets of graphical controls for composing the user interface using WYSIWYG integrated development environment. The thirst set is intended to inspect the user interface static display during the design phase. This inspection is elaborated by the control itself according to ergonomic guidelines. The second set consists in evaluating user interfaces by analyzing the interaction between the user and the interface. This set of controls operates with an electronic informer dedicated to user interface evaluation. An evaluation of these two contributions as well as research perspectives concludes this present report.

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