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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

Development of an Electrochemical Technique for High-ZTBi2Te3 Thin Film Deposition and Micro Thermoelectric cooler

Zeng, Guo-Yuan 18 July 2005 (has links)
Today¡¦s electronic components draw high levels of power and run at high temperature, which can present overheating problems for engineers and designers. They must find ways to keep the equipment cool or watch them fail prematurely. The conventional thermoelectric devices are high power consµming and slow response. We need more integrated and high performance thermoelectric device. Because of the limit of material characteristics, the figure of art rising with the quality of epitaxial layer. We gave a cheaper and easier fabrication to realized this demand. We present a micro thermoelectric device fabricated by Bi2Te3 electrochemical process. By using rotary cathode electrode, the current density can be well-proportioned. The thermal conduction and resistivity can be optimizing by this design. Also using the MEMS technology with repeated exposure and development of multiple photoresist layers, several different metals (Au, Cr) and thermoelectric materials (Bi2Te3, Sb2Te3) are fabricated. The SiO2 of 0.5µm was grown. Then the 0.3£gm-thick Au on oxidized Si sputtered with a 1£gm thick layer of Cr. And the bottom electrode was patterned by lift-off. Thick positive photoresist with one set of holes developed. Bi2Te3 was deposited by electrochemical deposition. And the Sb2Te3 is growing with the same method. The upper electrode sputtered with thin Au film and pattern by lift-off. Finally, Cr was etched to electrically isolate the bottom interconnects. The area of Bi2Te3 is about 50x50£gm2. And it¡¦s high about 5£gm. The ZT value of Bi2Te3, which is measured and verified to be around 0.0088.
2

Managed pressure drilling techniques and tools

Martin, Matthew Daniel 16 August 2006 (has links)
The economics of drilling offshore wells is important as we drill more wells in deeper water. Drilling-related problems, including stuck pipe, lost circulation, and excessive mud cost, show the need for better drilling technology. If we can solve these problems, the economics of drilling the wells will improve, thus enabling the industry to drill wells that were previously uneconomical. Managed pressure drilling (MPD) is a new technology that enables a driller to more precisely control annular pressures in the wellbore to prevent these drillingrelated problems. This paper traces the history of MPD, showing how different techniques can reduce drilling problems. MPD improves the economics of drilling wells by reducing drilling problems. Further economic studies are necessary to determine exactly how much cost savings MPD can provide in certain situation. Furter research is also necessary on the various MPD techniques to increase their effectiveness.
3

Parents' perceptions of early childhood development in the Langkloof farming communities / S.L.D. Kemmies.

Kemmies, Sharelda Luanshia Davidene January 2013 (has links)
Early childhood development has a lifelong impact on the future of each human being. However, all South Africans do not have equal access to the same quality ECD opportunities and services. As a means to advance knowledge in this regard, this study explores parents' perceptions regarding early childhood development (ECD) and their involvement therein, particularly within the Langkloof farming communities. Furthermore, the objective is to formulate guidelines, which can be applied to promote parents‘ involvement in ECD at home and at the ECD partial care facility the children are enrolled at. For this reason an interpretive, descriptive research design was utilised as methodology, which enables the determination of practical applicability. The data for this study was gathered by means of five focus groups, consisting of not more than eight participants per group. Participants were sampled though a purposeful sampling strategy to ensure that the most informative participants were selected for the study. Gathered data were transcribed and analysed on the basis of the basic qualitative analysis process, incorporating the thematic analysis strategy. The findings of this study indicate that parents have a pertinent understanding of ECD and parental involvement in relation to existing literature on ECD. Participants‘ perceptions complement existing ECD-related literature, indicating that parental involvement in ECD includes a home-centred as well as a facility-centred approach. Participants made reference to their concerns and satisfactions with the ECD services that they are currently receiving. They furthermore made reference to the challenges that prohibit them from optimal parental involvement in the ECD of their children, both at home, as well as at the ECD partial care facilities their children are enrolled at. Participants made suggestions on how they could be supported to address their concerns and challenges in both home-centred and facility-centred approaches in order to enhance parental involvement in their community. In general findings suggest that parents have the skills and are aware of their rights and responsibilities with regard to ECD parental involvement. However, if their insights were to be additionally buttressed in particular ways, their children‘s development in the early years could be enhanced. Based on the findings therefore, this study recommends that governmental departments focus on determining the actual requirements of parents, based on their unique understanding of their circumstances and beliefs by means of practice-based research in less fortunate communities. Furthermore it is recommended that government departments, other role players involved in community-based ECD service delivery and farm owners should play a developmental, empowering and supportive role to assist parents to improve in respect of home-centred, as well as facility-centred parental involvement in ECD. In general the findings of this study therefore suggest that support services to parental involvement in ECD must be individualised based on research and theory and the requirements of parents and children in a specific context. / Thesis (MSW)--North-West University, Potchefstroom Campus, 2013.
4

Parents' perceptions of early childhood development in the Langkloof farming communities / S.L.D. Kemmies.

Kemmies, Sharelda Luanshia Davidene January 2013 (has links)
Early childhood development has a lifelong impact on the future of each human being. However, all South Africans do not have equal access to the same quality ECD opportunities and services. As a means to advance knowledge in this regard, this study explores parents' perceptions regarding early childhood development (ECD) and their involvement therein, particularly within the Langkloof farming communities. Furthermore, the objective is to formulate guidelines, which can be applied to promote parents‘ involvement in ECD at home and at the ECD partial care facility the children are enrolled at. For this reason an interpretive, descriptive research design was utilised as methodology, which enables the determination of practical applicability. The data for this study was gathered by means of five focus groups, consisting of not more than eight participants per group. Participants were sampled though a purposeful sampling strategy to ensure that the most informative participants were selected for the study. Gathered data were transcribed and analysed on the basis of the basic qualitative analysis process, incorporating the thematic analysis strategy. The findings of this study indicate that parents have a pertinent understanding of ECD and parental involvement in relation to existing literature on ECD. Participants‘ perceptions complement existing ECD-related literature, indicating that parental involvement in ECD includes a home-centred as well as a facility-centred approach. Participants made reference to their concerns and satisfactions with the ECD services that they are currently receiving. They furthermore made reference to the challenges that prohibit them from optimal parental involvement in the ECD of their children, both at home, as well as at the ECD partial care facilities their children are enrolled at. Participants made suggestions on how they could be supported to address their concerns and challenges in both home-centred and facility-centred approaches in order to enhance parental involvement in their community. In general findings suggest that parents have the skills and are aware of their rights and responsibilities with regard to ECD parental involvement. However, if their insights were to be additionally buttressed in particular ways, their children‘s development in the early years could be enhanced. Based on the findings therefore, this study recommends that governmental departments focus on determining the actual requirements of parents, based on their unique understanding of their circumstances and beliefs by means of practice-based research in less fortunate communities. Furthermore it is recommended that government departments, other role players involved in community-based ECD service delivery and farm owners should play a developmental, empowering and supportive role to assist parents to improve in respect of home-centred, as well as facility-centred parental involvement in ECD. In general the findings of this study therefore suggest that support services to parental involvement in ECD must be individualised based on research and theory and the requirements of parents and children in a specific context. / Thesis (MSW)--North-West University, Potchefstroom Campus, 2013.
5

Contribution à l’élaboration d’un processus d’extraction des architectures logicielles : Méta-modèle, méthode et outil / A contribution to the development of a software architecture extraction process : Meta-model, method and tool

Abboud, MIra 27 October 2017 (has links)
Face à la complexité croissante des systèmes logiciels, les architectures logicielles sont apparues comme un allié précieux pour la conception et la maintenance de ces systèmes. Cependant, pour de nombreux systèmes, la représentation de leur architecture n’est pas fiable ; elle est soit indisponible, soit insuffisante ou soit non mise à jour. Pour pallier ce problème qui met en danger la maintenance, l’évolution, la réutilisation et la migration d’un système, l’extraction d’une architecture du système est souvent proposée comme une bonne alternative. L’extraction d’une architecture logicielle est définie comme la science de l’analyse et de la conversion du code source en une architecture logicielle. Cette thèse contribue à apporter une solution au problème d’inexistence d’outil de mesure pour les processus d’extraction d’une architecture logicielle. Ainsi, nous proposons un méta-modèle appelé SArEM qui spécifie les différents processus d’extraction d’une architecture logicielle. Le méta-modèle est basé sur le métamodèle SPEM et couvre les principaux concepts des processus d’extraction d’une architecture logicielle. En outre, nous fournissons un outil qui permet aux architectes de construire leur propre processus, d’interagir avec les sorties générées et de découvrir une architecture logicielle conforme à leurs souhaits. Plus précisément, nous proposons une approche d’extraction d’une architecture logicielle appelée SAD basée sur ECD. SAD consiste à considérer l’extraction d’une architecture logicielle comme un processus de découverte de nouvelles connaissances. Ainsi, notre contribution est articulée autour deux points : le premier point est la suggestion d’un processus générique pour l’extraction d’une architecture logicielle et le second point est l’élaboration d’une extension d’un outil ECD qui supporte l’exécution des processus d’extraction d’une architecture logicielle. / Face to the exponential growth in the size and complexity of software systems, software architectures emerge as a valuable ally for the design and maintenance of these systems. However, for many systems, their architecture representation is not reliable; it might be unavailable, insufficient, or out of date. To overcome this problem that puts the system maintenance, evolution, reuse and migration in danger, the extraction of the system architecture is proposed. The latter is defined as the science of analyzing and converting the source code to a software architecture. The thesis treats the gap of a measurement tool for software architecture extraction processes. We propose a meta-model called SArEM (Software Architecture Extraction Meta-model) that specifies the software architecture extraction processes. The meta-model is based on SPEM meta-model and covers the main concepts of software architecture extraction processes. Furthermore, we provide a manner that allows the architects to build their own process, interact with the generated outputs and discover a software architecture that satisfies them. Specifically, we propose a software architecture extraction approach called SAD (Software Architecture Discovery) based on KDD. SAD consists in considering the extraction of a software architecture as a process of discovering new knowledge. Thus, the contribution is centered on two points: the first point is the suggestion of a generic software architecture extraction process and the second point is the elaboration of a KDD tool extension that supports the execution of software architecture extraction processes.
6

A multi-stakeholder abridged environmentally conscious design approach

O. Connor, Francis Joseph January 2000 (has links)
No description available.
7

Polysaccharide Materials and Sorption Studies of Chloroform and Total Trihalomethanes (TTHMs) in Aqueous Solution

2013 March 1900 (has links)
In this research, a series of synthetically engineered copolymers were synthesized containing polysaccharides (e.g., β-cyclodextrin and chitosan) to address the removal of trihalomethanes (THMs) from water environments. There are two main parts in this research thesis: i) the preparation and characterization of polysaccharide-based copolymers; ii) sorption studies of the copolymers with chloroform and total THMs (TTHMs) in aqueous solution. In the first part of this thesis, grafted polyester, polyester and grafted polyamide copolymers were prepared by cross-linking β-cyclodextrin (β-CD) and chitosan (CS) with various cross-linkers, including poly (acrylic acid) (PAA), terephthaloyl (TCl), and sebacoyl chloride (SCl), respectively. The synthesized copolymer materials were characterized by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), elemental (C and H) analyses, and NMR spectroscopy. Nitrogen porosimetry was used to analyze the surface area and pore structure characteristics of the copolymers and starting materials in solid state. The sorption properties of the copolymers in aqueous solution were studied using different dye probes (e.g., p-nitrophenol and methylene blue) by UV–Vis spectrophotometry. The copolymers showed markedly varied interactions with dye probes in accordance with their composition, surface area, and pore structure characteristics. Diverse materials were afforded by variation of the synthetic conditions. The sorption isotherms were evaluated with various isotherm models (e.g., Langmuir, BET, Freundlich and Sips). The Sips isotherm showed the best overall agreement with the experimental results and the sorption parameters provided estimates of the sorbent surface area and the sorption capacity for various copolymers in aqueous solution. The copolymer sorbents display tunable physicochemical properties according to the synthetic conditions. In the second part of this thesis, the direct aqueous injection (DAI) method with gas chromatography (GC) with electron capture or electrolytic conductivity detectors (ECD) enabled quantitative detection of chloroform and TTHMs in water. A preliminary adsorption study and kinetic study of chloroform provided the information to establish the experimental protocol for the sorption study. The sorption parameters were evaluated using the Sips model. The sorption capacity (Qm) values of chloroform for these synthetically engineered copolymers at similar conditions ranged from 0.00335-1.70 mmol/g. The relative ordering of the Qm values was observed: β-CD/PAA 1:5 > SCl-5 > SCl-10 ~ CP-1 > β-CD/PAA 1:10 > CP-5 > AC > β-CD/PAA 1:5 at high mixing speed. An extension of the sorption study for copolymers toward the multi-component THMs in water was carried out. The copolymers showed distinct adsorption capacities to THMs: chloroform (0.0485-0.287 mmol/g); DBCM (0.0712-0.277 mmol/g); BDCM (0.0684-0.387mmol/g); and bromoform (0.0522-1.07 mmol/g). The copolymers exhibited relatively high selectivity toward individual components of THMs due to their variable molecular size and polarizability. The copolymers showed favorable adsorption (e.g., β-CD/PAA 1:5, CP-1) and each type of polysaccharide (e.g., β-CD and CS) copolymers displays great potential for the removal of halomethane-based contaminants.
8

Proactive integration of environmental con-cerns in business operations and organiza-tional structure: ECD&M and EMS : Case studies: Volvo Buses, Trelleborg AB, Kinnarps AB

Gazhilieva, Anna, Pino Avila, Andrea January 2010 (has links)
Over the last decades, industrial development has brought prosperity and wealth together with triggering unintended ecological degradation. Therefore, a modern society has increasingly demanded companies to take responsibilities for the effects of those business activities that have a negative impact on the environment. Among businesses this has increased the interest towards adopting proactive approaches and practices which aim to reduce these negative impacts. Therefore, the topic of proactive integration of environmental concerns into or-ganizational structure and day-to-day operations is highly relevant and deserves to be investigated. The purpose of this thesis is to analyze why and how companies integrate environmental concerns in their business operations and organizational structure as well as to investigate the critical factors that enable such integration. In this thesis, the integrated deductive and inductive research approaches are applied and the qualitative study is selected in order to better understand the motivations, challenges and perceived benefits for companies when proactively integrating environmental concerns into their business operations and organizational framework. Moreover, the multiple cases study of three Swedish manufacturing companies, namely: Volvo Buses, Trelleborg and Kinnarps is selected as the research strategy. By conducting semi-structured in-depth interviews with the environmental managers, there has not been found a generic pattern as for the ways of incorporating environmental concerns into the operational activities and organizational structure. Nevertheless, the evidence of performing environmentally-conscious design and manufacturing (ECD&M) as well as implementing environmental management systems (EMSs) for achieving improvements in material utilization, hazardous waste and emissions reduction, efficient energy consumption and the use of different systems to prevent possible accidents and environmental emergencies have been identified in the studied manufacturing companies. The thesis concludes with the essence of main reasons and benefits from adopting the environmental practices and eco-efficient strategies. Furthermore, the empirical results focus on the tools and methodologies supporting this proactive adoption. Thus, while Design for Environment (DFE) has gained much attention in theory, still only some elements of this methodology are being experienced by studied companies. In line with this, material selection process is recognized in all three organizations as a vital component in product design. As for Life Cycle Assessment (LCA), although is the most reliable method for outlining the environmental performance of products still its use and implementation is disadvantaged by its complexity, comprehensive scope and time-intensive application. The empirical results also show that the focus on products, unlike manufacturing processes and manufacturing facili-ties, is still neglected to a certain degree. Furthermore, products are still not within the main focus of ISO 14001. Consequently, from an environmental point of view, EMS covering a wider scope would be preferable and a more useful tool when striving for a sustainable development. Finally, some critical factors for a successful integration of the environmental concerns in business practices are also identified.
9

Proactive integration of environmental con-cerns in business operations and organiza-tional structure: ECD&M and EMS : Case studies: Volvo Buses, Trelleborg AB, Kinnarps AB

Gazhilieva, Anna, Pino Avila, Andrea January 2010 (has links)
<p>Over the last decades, industrial development has brought prosperity and wealth together with triggering unintended ecological degradation. Therefore, a modern society has increasingly demanded companies to take responsibilities for the effects of those business activities that have a negative impact on the environment. Among businesses this has increased the interest towards adopting proactive approaches and practices which aim to reduce these negative impacts. Therefore, the topic of proactive integration of environmental concerns into or-ganizational structure and day-to-day operations is highly relevant and deserves to be investigated.</p><p>The purpose of this thesis is to analyze why and how companies integrate environmental concerns in their business operations and organizational structure as well as to investigate the critical factors that enable such integration. In this thesis, the integrated deductive and inductive research approaches are applied and the qualitative study is selected in order to better understand the motivations, challenges and perceived benefits for companies when proactively integrating environmental concerns into their business operations and organizational framework. Moreover, the multiple cases study of three Swedish manufacturing companies, namely: Volvo Buses, Trelleborg and Kinnarps is selected as the research strategy. By conducting semi-structured in-depth interviews with the environmental managers, there has not been found a generic pattern as for the ways of incorporating environmental concerns into the operational activities and organizational structure. Nevertheless, the evidence of performing environmentally-conscious design and manufacturing (ECD&M) as well as implementing environmental management systems (EMSs) for achieving improvements in material utilization, hazardous waste and emissions reduction, efficient energy consumption and the use of different systems to prevent possible accidents and environmental emergencies have been identified in the studied manufacturing companies.</p><p>The thesis concludes with the essence of main reasons and benefits from adopting the environmental practices and eco-efficient strategies. Furthermore, the empirical results focus on the tools and methodologies supporting this proactive adoption. Thus, while Design for Environment (DFE) has gained much attention in theory, still only some elements of this methodology are being experienced by studied companies. In line with this, material selection process is recognized in all three organizations as a vital component in product design. As for Life Cycle Assessment (LCA), although is the most reliable method for outlining the environmental performance of products still its use and implementation is disadvantaged by its complexity, comprehensive scope and time-intensive application. The empirical results also show that the focus on products, unlike manufacturing processes and manufacturing facili-ties, is still neglected to a certain degree. Furthermore, products are still not within the main focus of ISO 14001. Consequently, from an environmental point of view, EMS covering a wider scope would be preferable and a more useful tool when striving for a sustainable development. Finally, some critical factors for a successful integration of the environmental concerns in business practices are also identified.</p>
10

Estabilidade de radiofármacos sob a influência de variações de umidade relativa

SANTOS, Elaine Vasconcelos dos 23 January 2015 (has links)
Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-02-23T19:02:39Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Elaine Vasconcelos dos Santos.pdf: 5212230 bytes, checksum: 5466df96d7209befd8083f1fce37eff2 (MD5) / Made available in DSpace on 2016-02-23T19:02:39Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Elaine Vasconcelos dos Santos.pdf: 5212230 bytes, checksum: 5466df96d7209befd8083f1fce37eff2 (MD5) Previous issue date: 2015-01-23 / CNPQ / Radiofármacos são traçadores radioativos utilizados na Medicina Nuclear, compostos por um fármaco com afinidade por órgãos ou processos metabólicos específicos e um radionuclídeo. Enquanto retidos no corpo do paciente, podem ser detectados e mapeados fornecendo informações quanto à presença de patologias ou disfunções na área em estudo. Entre os mais utilizados se destacam os radiofármacos marcados com 99mTc e 18F. A cinética de distribuição destes compostos no organismo pode ser afetada em decorrência da influência de fatores ambientais na estabilidade do medicamento. Conforme a legislação sanitária brasileira, estudos de estabilidade devem ser conduzidos e um dos parâmetros a serem avaliados é a umidade relativa. O objetivo deste trabalho foi avaliar o efeito da umidade na estabilidade de radiofármacos marcados com 99mTc e 18F por meio de determinações periódicas da pureza radioquímica e do pH de amostras de Sestamibi-99mTc, ECD-99mTc e FDG-18F. As medições da pureza radioquímica foram feitas por meio de cromatografia em camada delgada utilizando as fases móveis e estacionárias descritas nas bulas dos medicamentos ou em compêndios oficiais. A medida do pH das amostras foi realizada utilizando-se papel indicador de pH. As amostras de radiofármacos marcados com 99mTc foram submetidas a umidades de 20% e 90% e analisadas ao longo de 24h. As amostras de FDG-18F foram submetidas a umidades de 20% a 90% e as análises foram conduzidas por 10 h. Os resultados obtidos para o radiofármaco Sestamibi-99mTc indicaram não haver influência da umidade relativa a que o medicamento foi submetido. Já os resultados obtidos para o ECD-99mTc mostram um perfil de decomposição radiolítica mais acelerado se comparado ao Sestamibi-99mTc, e sugerem a influência de umidades relativas altas (90%) na estabilidade do composto. As amostras de FDG-18F não apresentaram variação significativa dentro da faixa de valores de umidade testados, o radiofármaco manteve-se apto para uso durante todo o período de testes (10h). / Radiopharmaceuticals are radioactive tracers utilized in nuclear medicine and consist of a radionuclide labeled with a drug with affinity for specific organs or metabolic processes. Administered to the patients, radiopharmaceuticals can be detected and mapped providing information about diseases or disorders in the studied area. The most utilized radiopharmaceuticals for diagnostics purposes are those labeled with 99mTc e 18F. The distribution kinetics of those compounds in the body can be affected due to the influence of environmental factors (such as temperature) on the drug stability. According to Brazilian health legislation, stability studies should be conducted taking into account the influence of relative humidity, although there was not found evidences of such influence on radiopharmaceuticals stability. The objective of this study was to evaluate the influence of humidity on the stability of radiopharmaceuticals labeled with 99mTc and 18F through periodic determinations of the radiochemical purity and the pH on Sestamibi-99mTc, ECD- 99mTc and FDG-18F samples. Measurements of radiochemical purity were carried out by means of thin layer chromatography using the mobile and stationary phases described in official compendia or in accordance to the radiopharmaceutical producer instructions. The pH measurement was performed using pH indicator papers. Samples of radiopharmaceuticals labeled with 99mTc were submitted to humidity of 20% and 90% and tested during 24h. FDG-18F samples were submitted to humidity from 20% up to 90% and analyzes were conducted during 10 h. The results for Sestamibi-99mTc radiopharmaceutical indicated no influence of the relative humidity on this drug stability. The results obtained to ECD-99mTc samples showed a faster radiolytic decomposition profile compared to Sestamibi-99mTc, suggesting the influence of high relative humidity (90%) on the stability of this compound. The 18FFDG samples showed no significant variation on their radiochemical purity and pH within the range of humidity tested, remaining suitable for use the time period considered in this study (10h).

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