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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

Electrically Anisotropic Layered Perovskite Single Crystal

Li, Ting-You 04 1900 (has links)
Organic-inorganic hybrid perovskites (OIHPs), which are promising materials for electronic and optoelectronic applications (1-10), have made into layered organic-inorganic hybrid perovskites (LOIHPs). These LOIHPs have been applied to thin-film transistors, solar cells and tunable wavelength phosphors (11-18). It is known that devices fabricated with single crystal exhibit the superior performance, which makes the growth of large-sized single crystals critical for future device applications (19-23). However, the difficulty in growing large-sized LOIHPs single crystal with superior electrical properties limits their practical applications. Here, we report a method to grow the centimeter-scaled LOIHP single crystal of [(HOC2H4NH3)2PbI4], demonstrating the potentials in mass production. After that, we reveal anisotropic electrical and optoelectronic properties which proved the carrier propagating along inorganic framework. The carrier mobility of in-inorganic-plane (in-plane) devices shows the average value of 45 cm2 V–1 s–1 which is about 100 times greater than the record of LOIHP devices (15), showing the importance of single crystal in device application. Moreover, the LOIHP single crystals show its ultra-short carrier lifetime of 42.7 ps and photoluminescence quantum efficiency (PLQE) of 25.4 %. We expect this report to be a start of LOIHPs for advanced applications in which the anisotropic properties are needed (24-25), and meets the demand of high-speed applications and fast-response applications.
2

Human resource development : an investigation into the nature and extent of training and development in the Saudi private manufacturing sector

Albahussain, Sami Abdullah M. A. January 2000 (has links)
This research explores the nature and extent of training and development (TD) provision, as well as top managers' and TD personnel's attitudes towards the TD function within the medium and large-size private manufacturing organisations of Saudi Arabia. Extensive details of the TD situation are provided and assessed for their adequacy, covering among other elements a descriptive analysis of the main characteristics of the organisations concerned, an evaluation of their TD plans and policies, and a review of their budget allocation and funding. The research then proceeds to describe and discuss the extent to which such organisations are applying a systems approach to TD, both in terms of its design and implementation. Thereafter, the main factors impeding the effectiveness of TD programmes are examined, followed by a consideration of the future challenges that are likely to increase the importance of TD for the organisations in question. The research has adopted a mainly descriptive approach and uses both quantitative and qualitative analytical methods. The required data were gathered through a combination of semi-structural interviews with a number of top managers, and survey questionnaires addressed to the persons responsible for TD within the targeted organisations. The sampling strategy was disproportional stratified random sampling. In total 16 senior executives, 132 medium-size organisations and 94 large-size organisations took part in the study. The findings reveal that although attitudes towards the value of TD are generally favourable, in practice in the majority of cases TD is under-resourced, unplanned and patchy, hardly the ideal features of a systematic model of TD that will enable private manufacturing business to successfully meet the challenges of the future ahead. The research ends with a number of specific and practical recommendations intended to improve the effectiveness of TD in the private manufacturing sector of the Kingdom of Saudi Arabia, as well as a number of suggestions for further research.
3

Dimensionamento dos sistemas de esgotos sanitários de grande porte via redução de custos / Design of the large sewer networks through costs reduction

Carlos Augusto de Carvalho Magalhães 10 August 1995 (has links)
A proposta do modelo computacional (DIMREDE) para dimensionamento de redes coletoras de esgotos sanitários de grande porte, a partir de um traçado conhecido, fundamenta-se na sua importância sanitária e ambiental, e na necessidade de minimizar os custos totais de tais sistemas. O modelo é destinado a microcomputadores, atendendo, portanto, aos requisitos de portabilidade. As redes de esgoto são projetadas para o regime de escoamento livre, embora em alguns casos, seja necessária a introdução de estações elevatórias em determinados pontos do sistema. O modelo prevê a incorporação dessas elevatórias, quando necessário, adicionando os respectivos custos no cômputo dos custos totais. As funções de custos utilizadas são baseadas em dados de redes executadas por companhias de saneamento do país. O DIMREDE permite também que, a equação governante da hidráulica de Hazen-Williams modificada, seja empregada. Trata-se de uma expressão que contempla fatores como a lâmina e velocidade de escoamento, diâmetro, declividade, material empregado no revestimento do conduto e viscosidade do fluido, na determinação do coeficiente de rugosidade, apresentando, desta forma, resultados mais condizentes com a realidade. / A computational model (DIMREDE) is proposed for design of large sewer networks whose layouts whose layouts are defined, based on their sanitary and environmental importance, as well as the costs minimization. The model is designed for microcomputers satisfying the portability criterion. In spite of the sewer networks being designed under free flow, many times the introduction of pump stations in such systems is necessary. The model evaluates costs of pump stations as part of the total cost function in terms of sewer networks already implemented by sanitation companies in Brazil. The DIMREDE program employs the modified Hazen-Williams equation for the system hydraulics, admiting that factors like depth, velocity, diameter, slope, lining material and fluid viscosity be considered in the determination of the coefficient of roughness, for obtaining more realistic results.
4

Dimensionamento dos sistemas de esgotos sanitários de grande porte via redução de custos / Design of the large sewer networks through costs reduction

Magalhães, Carlos Augusto de Carvalho 10 August 1995 (has links)
A proposta do modelo computacional (DIMREDE) para dimensionamento de redes coletoras de esgotos sanitários de grande porte, a partir de um traçado conhecido, fundamenta-se na sua importância sanitária e ambiental, e na necessidade de minimizar os custos totais de tais sistemas. O modelo é destinado a microcomputadores, atendendo, portanto, aos requisitos de portabilidade. As redes de esgoto são projetadas para o regime de escoamento livre, embora em alguns casos, seja necessária a introdução de estações elevatórias em determinados pontos do sistema. O modelo prevê a incorporação dessas elevatórias, quando necessário, adicionando os respectivos custos no cômputo dos custos totais. As funções de custos utilizadas são baseadas em dados de redes executadas por companhias de saneamento do país. O DIMREDE permite também que, a equação governante da hidráulica de Hazen-Williams modificada, seja empregada. Trata-se de uma expressão que contempla fatores como a lâmina e velocidade de escoamento, diâmetro, declividade, material empregado no revestimento do conduto e viscosidade do fluido, na determinação do coeficiente de rugosidade, apresentando, desta forma, resultados mais condizentes com a realidade. / A computational model (DIMREDE) is proposed for design of large sewer networks whose layouts whose layouts are defined, based on their sanitary and environmental importance, as well as the costs minimization. The model is designed for microcomputers satisfying the portability criterion. In spite of the sewer networks being designed under free flow, many times the introduction of pump stations in such systems is necessary. The model evaluates costs of pump stations as part of the total cost function in terms of sewer networks already implemented by sanitation companies in Brazil. The DIMREDE program employs the modified Hazen-Williams equation for the system hydraulics, admiting that factors like depth, velocity, diameter, slope, lining material and fluid viscosity be considered in the determination of the coefficient of roughness, for obtaining more realistic results.
5

The Study of Price Forecasting Model for Large Size TFT-LCD Panel

Ko, Ren-Shawn 14 July 2009 (has links)
Larger size TFT-LCD panels, consists of notebook panel, monitor panel, and TV panel, enjoys great growth momentum for years. To fulfill the growing demand, panel makers keep continuous investment for expansion. Therefore, this creates over-supply, under-supply, or balanced supply-demand. Supply and demand decides the price of an item. So does TFT-LCD panel. Through thorough industry historic and forecasted data, complete supply-demand model is built with 2 years forward forecast. The result shows that in the following 2 years the occurrence of oversupply is very possible. However by controlling utilization rate and carefully talking orders, panel makers create shortage-like situation to raise panel price successfully. By the result of this model, accompanied with current global economics situations, some managerial suggestions are given for TFT-LCD makers.
6

Caractéristaion des effets spatiaux dans les grands coeurs RNR : méthodes, outils et études / Characterization of spatial effects in fast reactor large size cores : methods, tools and studies

Maillot, Maxence 28 September 2016 (has links)
Les réacteurs nucléaires à neutrons rapides sont une solution à long terme pour la production d’énergie car ils valorisent le Plutonium et peuvent utiliser tout le stock de d’Uranium appauvri. Les contraintes actuelles en termes de sûreté requièrent néanmoins des innovations pour favoriser un comportement naturel du cœur lors de transitoires incidentels en augmentant le temps de grâce et la marge à la fusion. Les innovations apportées aux cœurs (hauteur réduite, cœur hétérogène, puissance volumique limitée) induisent un accroissement de la taille des réacteurs. Cette évolution a des conséquences de sûreté essentiellement positives comme la réduction de l’effet de vidange mais d’autres comme la déformation de la nappe de puissance méritent attention. Cette thèse a permis de mieux appréhender ces spécificités au travers du calcul et de l’analyse des harmoniques du flux puis des matrices de fission. Ces études, en soutien au cœur d’ASTRID, ont permis de conforter les options de conception. / The need for energy is a matter of growing concern in the world today, in relation to global climate change. Nuclear energy is of interest because it does not produce greenhouse gases, and it is able to generate a substantial amount of energy at a given time. However, it needs fissile material to operate. Fuel economy is then a sine qua none condition for the development of this energy. Sodium Fast Reactors are a solution for the future of nuclear energy. These reactors are indeed able to use much less Uranium for the same amount of energy released. However, the safety constraints in accordance with todays standards (“forgiving behavior”) require new core designs, which are highly heterogeneous axially and rather flat. Finally, this evolution in reactor design (reduced power density and limited axial height) implies a significant increase in the reactor diameter. It has consequences from both an economic (Pu inventory, vessel size) and operational (power shape stabilization during irradiation) point of view. The understanding of this phenomena is the topic of this PhD.
7

Human resource development: An investigation into the nature and extent of training and development in the Saudi private manufacturing sector.

Albahussain, Sami A.M.A. January 2000 (has links)
This research explores the nature and extent of training and development (TD) provision, as well as top managers' and TD personnel's attitudes towards the TD function within the medium and large-size private manufacturing organisations of Saudi Arabia. Extensive details of the TD situation are provided and assessed for their adequacy, covering among other elements a descriptive analysis of the main characteristics of the organisations concerned, an evaluation of their TD plans and policies, and a review of their budget allocation and funding. The research then proceeds to describe and discuss the extent to which such organisations are applying a systems approach to TD, both in terms of its design and implementation. Thereafter, the main factors impeding the effectiveness of TD programmes are examined, followed by a consideration of the future challenges that are likely to increase the importance of TD for the organisations in question. The research has adopted a mainly descriptive approach and uses both quantitative and qualitative analytical methods. The required data were gathered through a combination of semi-structural interviews with a number of top managers, and survey questionnaires addressed to the persons responsible for TD within the targeted organisations. The sampling strategy was disproportional stratified random sampling. In total 16 senior executives, 132 medium-size organisations and 94 large-size organisations took part in the study. The findings reveal that although attitudes towards the value of TD are generally favourable, in practice in the majority of cases TD is under-resourced, unplanned and patchy, hardly the ideal features of a systematic model of TD that will enable private manufacturing business to successfully meet the challenges of the future ahead. The research ends with a number of specific and practical recommendations intended to improve the effectiveness of TD in the private manufacturing sector of the Kingdom of Saudi Arabia, as well as a number of suggestions for further research. / Government of Saudi Arabia
8

Sistemas de gestão ambiental: um estudo em empresa médio-grande / Environmental management systems: a study in a medium - large size company

Mendonça, Paulo Renato 12 November 2014 (has links)
Made available in DSpace on 2016-04-25T16:44:41Z (GMT). No. of bitstreams: 1 Paulo Renato Mendonca.pdf: 4324640 bytes, checksum: 2f1f96a9fa954b97a5aacf6ce9914f8c (MD5) Previous issue date: 2014-11-12 / This study discusses the adoption of dedicated, non-certified Environmental Management Systems (EMS‟s) for medium-large size companies as a way to obtain access to an EMS that could meet fundamental requirements of good environmental management practices and obtain satisfactory environmental and economic results at lower costs. The investigation methodology utilized is a case study of one average-large company that developed and implemented a dedicated, non-certified EMS working since June/2011. The conclusion of the investigations conducted by this study is that medium-large size companies can obtain sastisfactory environmental and economic results by adopting such kind of EMS. The study also makes evident that the results observed are consequence of the consistency of the indicators, administrative practices and structures introduced by the EMS investigated and the good quality of the work and engagement of the company‟s top management towards supporting the continuity of the programs, actions and investments that grant the success of the system. Taking into consideration the importance for the medium-large size companies of reducing costs carried by their EMS management and the commitment of the top management with it, as well as by having in view that such top management engagement could be of different kind and intensity for different companies, it is suggested the extension of this kind of study to other medium-size companies, aiming to verify the results obtained in this case study / O presente trabalho discute a adoção de sistemas de Gestão Ambiental (SGAs) próprios, não certificados, para empresas médio-grandes como via de acesso a um SGA que atenda a quesitos fundamentais das boas práticas de administração ambiental a custos mais baixos e que possa produzir resultados de desempenho ambiental e econômico adequados. A metodologia de investigação empregada é um estudo de caso de uma empresa médio-grande que desenvolveu um SGA próprio não certificado, em operação desde junho de 2011. A conclusão das investigações realizadas é que as empresas médio-grandes poderão obter resultados ambientais e econômicos adequados com a adoção de tais SGAs. Evidenciou-se que os resultados observados são consequência da consistência dos indicadores, das estruturas e práticas administrativas introduzidos pelo SGA pesquisado, aliados à qualidade do trabalho e ao engajamento e comprometimento da alta administração da empresa no sentido de suportar a continuidade dos programas, ações e investimentos que garantam o sucesso do sistema. Tendo em vista a importância para as empresas médio-grandes da redução dos custos com a administração de seus SGAs e do comprometimento da alta administração com o funcionamento do sistema, e considerando-se que tal disposição ao engajamento da alta administração poderá ser de diferentes graus para variadas situações que possam ser encontradas no universo empresarial, sugere-se a extensão e aplicação desta forma de pesquisa a outras empresas médio-grandes que se utilizem de SGAs próprios e não certificados, objetivando a verificação dos resultados obtidos neste estudo de caso
9

Pre-study and Conceptual Design of a Hydrogen Fuel Cell Driven Wheel Loader / Förstudie och Konceptuell Design av en Vätgas Bränslecell-driven Hjullastare

Caspari, Jana, Bernatavicius, Pijus January 2022 (has links)
Volvo Construction Equipment is one of the leading construction machinery manufacturers in the world. To stay amongst the leaders, research and development projects for new technologies are crucial. The most important path of development today is the reduction of emissions produced by these heavy duty vehicles. To tackle this challenge, several technologies are already used in industry. One example are hybrid machines that combine a conventional diesel engine with batteries, resulting in reduced engine size and pollutants. Another option are full battery-electric vehicles, which can reduce the on-site emissions to zero. The electrochemical processes within batteries are however comparable slow and result in long recharge times. A new focus of development within the industry are hybrid systems combining fuel cells and batteries. Since hydrogen can be refueled almost as fast as convenient fuel, it solves the issue of long recharge times. Additionally, the reaction is emission free, since there is no combustion process and the only byproduct that is emitted from the fuel cell is chemically clean water. This thesis aims to propose an architecture and packaging solution to replace the diesel engine in a large size wheel loader with a fuel cell power system. This also includes all respective auxiliary systems, i.e. energy storage, cooling and electric systems. Achieving the same performance as a conventional large size wheel loader as well as keeping the spatial envelope the same are the main objectives of this work. To achieve these goals, an extensive study on the most common drive cycles is carried out to understand the power demand of the machine. After the selection of an energy storage system based on a MATLAB simulation script, a cooling system is modelled and scaled to fulfill the operating requirements of the different components. Eventually, all systems are modeled and installed into the wheel loader in CATIA V5. The study showed, that the new system architecture of the vehicle can be fitted into the existing engine bay with a slight extension of the rear frame and hood. Two power optimized batteries are combined with one fuel cell. Hydrogen tanks with a filling volume of 478 [L] can be installed in the machine, covering 50% of the customer population curve without degradation of performance. This includes one refill of the wheel loader during the day. The performance parameters match the conventional machine up to a high degree, concluding that the conversion of a large size wheel loader into a fuel cell powered wheel loader is feasible.
10

Clothing Preferences of Large-Size Women Who Shop in Large-Size Specialty Stores in the North Dallas Area

Meriwether, Judith 05 1900 (has links)
This study investigated the clothing preferences of large-size women who shopped in selected large-size specialty stores in North Dallas. Questions were asked regarding the respondents' age, employment, income, dress size and degree of fashion-consciousness. Also investigated were preferences regarding apparel and shopping sources. A questionnaire was used to obtain the desired information. Based on the data obtained, it was found that large-size women have certain preferences concerning the clothing they purchase and the sources they shop.

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