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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.
381

Solutions of pitfalls on¡§Third Party Logistics¡¨ industry

Chiu, Teng-Yu 31 July 2006 (has links)
According to the author¡¦s professional observations of the 3PL industrial situations and problems, the main issue of this paper is to present real cases providing solutions on 3PL industrial pitfalls. In this paper, the pitfalls of ¡§Third party logistics¡¨ industry actually focus on the ¡§NVOCC¡¨ services, which indicate the vicious competitions of price for these decades. Due to the low entry barrier and low cost requirements; 3PL industry originally is under a keen competitive environment. Plus, because of the different price structure of underlying carrier during the recent decades, for 3PLs, the vicious cycle of NVOCC becomes more and more serious. Therefore, in this paper, author analyzes two practical cases based on existing literature review. The main purpose here is finding out the efficient suggestions of solutions on breaking this vicious cycle of competition by improving the core competitiveness from both internal services offering and external logistic network.
382

Seasonal abundance and control of economically important ticks on a commercial game ranch, Thabazimbi, Limpopo Province.

Schroder, Bradley. January 2012 (has links)
M. Tech. Nature Conservation / Ticks are blood feeding external parasites of mammals, birds, and reptiles throughout the world. Tick infestation is considered to be one of the main constraints to successful game ranching in southern Africa. Several blood parasites are transmitted by ticks and have been incriminated as the cause of death in several wildlife species Ticks thus affect wildlife and domestic animal management worldwide, with approximately 850 species of ticks having been described The aim of the thesis is to collect and describe fully the nature and extent of the tick cohort of a semi-intensive and control free game ranch in the Limpopo Province of South Africa farm and to establish the environmental management effects on tick abundances and species.
383

The future of national flag carriers in developing countries : air Botswana’s privatisation struggle

Molwelwa, Onalenna January 2011 (has links)
<p>The study looked particularly at the operations of national carriers and governments&lsquo / efforts to sustain the airlines&lsquo / operations. Evidence has shown that many countries struggle to maintain operations of their flag carriers, but few countries are willing to completely leave the airlines in the hands of the private sector because of national pride. On the other hand, many of those airlines that get into private hands fail and end up being closed down or go back into state hands. These airlines are also perceived to be development tools, in particular for tourism development which is a predominant economic activity in many developing countries. For this reason, many states do not favour privatisation, even though the perception is that the airline industry is better handled by private businesses. The main conclusion of the study for Botswana is therefore that neither full state ownership nor full privatisation is the solution to addressing the problem of ailing flag carriers. There is no single solution, but a combination of several. A broader global view of national airline operations clearly shows that approaches adopted by many successful national airlines, in both developed and developing countries, is some form of partial privatisation.</p>
384

The history of ticks and tick-borne diseases in cattle in Natal and Zululand (KwaZulu-Natal) from 1896 to the present.

Manamela, David Modikana Solomon. January 2001 (has links)
The main objective oft his dissertation was to identify the causes of the rise of the tick population in KwaZulu-Natal in 1999. After 100 years of intensive chemical tick control, tick numbers remain high and the stock losses caused by tick borne diseases are still significant. In South Africa legislation was introduced to support intensive chemical tick control. Ticks have consistently shown themselves to possess a genetic pool containing the potential to resist a wide range of chemical poisons. The introduction of new chemicals followed by widespread use, has often resulted in the appearance of a tick population resistant to those chemicals. The problem is compounded by the fact that some farmers are also found to be helping ticks to multiply by not following instructions given by the chemical industry on how to use dips. Chemicals which are used to control ticks are also beyond the financial means of many cattle owners especially in resource- poor communities. Apart from the high cost of intensive tick control, the chemicals that are used to destroy ticks are very poisonous, not only to ticks but to the birds which are natural predators of ticks. The negative effects of these chemicals on the environment combined with the high cost of tick control has forced a revision of intensive chemical tick control strategy. There is now a shift to use methods of tick control which are friendly to the environment and affordable to the resource-poor communities. This dissertation provides a historical overview of the problem in KwaZulu-Natal and recommendations on how to deal with the problem in future. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.
385

Ett salt i kulturdebatten : Mångbottnade berättelser om Stockholms stadsteater

Mujkic, Leonora January 2013 (has links)
Stockholms stadsteater (Stockholm’s city theatre) is a public theatre in Stockholm, Sweden. During the last ten years, the theatre has increased its audience by 40 percent, has been called a ”success story” by culture politicians in Stockholm as well as others in the cultural field, and is today the largest theatre in the Nordic countries. At the same time, there is a recurring debate, primarily in the national morning papers’ culture sections, concerning Stockholms stadsteater. The debate often concerns the theatre’s ongoing organizational changes, usually in the form of a constant striving towards a more effective organization, as well as its negative results in the annual employee surveys. Despite usually positive reviews of its productions, Stockholms stadsteater has also been criticized for choosing to set up what by some is considered to be mainstream and commercial productions (for example musicals) at the expense of smaller, more artistic, ones. The main purpose of this study is to analyze different descriptions of Stockholms stadsteater during the years 2004-2013, by using the development of the Swedish cultural policy as background, and institutional organizational theory as the frame of reference. How cultural policy ideas are used in the different stories about Stockholms stadsteater, and the potential conflicts that exist between these different descriptions, is analyzed by using institutional theories about editing, translation and carriers of ideas. The study, based on text analysis and interviews, shows that Stockholms stadsteater is described as a role model and a recipe for success, as well as an effective and modern organization. The theatre is also described as a trademark, as well as part of a defense of democracy and the intrinsic value of culture. The analysis further shows that the different ideas about the theatre are sometimes used – that is, edited and translated – in different ways by different people and in different contexts. It also suggests that the idea of an effective organization can be considered as the main idea in the descriptions of Stockholms stadsteater. In the material studied, the thought of effectiveness is almost always present and something that other ideas often need to relate to in order to be perceived as legitimate. On the other hand, although the idea of effectiveness is important, it can also be controversial. For this reason, it can be edited to fit other cultural policy ideas better. One example is describing the intrinsic value of culture, in this case theatre, as something which is protected by organizations becoming more effective, and thus being able to use their resources to produce more qualitative theatre for more people.
386

Induction of maize wallaby ear disease by Cicadulina bimaculata and its incidental infection by leafhopper A virus / by Felix Ofori

Ofori, Felix January 1984 (has links)
Bibliography: leaves 62-64 / iii, 64 leaves, [16] plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Pathology, 1985
387

Interactions between common vertebrate hosts and the mosquito vectors of Ross River and Barmah Forest viruses in urban Brisbane, South East Queensland, Australia /

Boyd, Ann Marie. January 2004 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2004. / Program shared between two schools. Includes bibliography.
388

Mesure de durée de vie de porteurs minoritaires dans les structures semiconductrices de basse dimensionnalité / Measurement of the lifetime and diffusion length of minority charge carriers in low dimensionality materials

Daanoune, Mehdi 03 February 2015 (has links)
La durée de vie des porteurs minoritaires est l'un des principaux paramètres mesurés dans les semi-conducteurs et la décroissance de photoconductivité (PCD) l'une des méthodes les plus largement utilisées pour ce type de mesure. Aujourd'hui, grâce aux divers équipements automatisés, la mesure de durée de vie est devenue une caractérisation de routine qui permet de juger de la qualité d'un matériau dans tous les secteurs utilisant les semi-conducteurs. Cependant, l'utilisation de micro- et nano-matériaux dans l'industrie du photovoltaïque et de la microélectronique requière l'adaptation des techniques existantes (PCD, photoluminescence etc.). En effet, avec la réduction des dimensions (couches ultraminces telles que les couches épitaxiées, couches SOI « silicon on insulator », et nanostructures), l'influence de la surface (états d'interfaces, pièges, etc.) devient prépondérante. La présence des substrats utilisés pour les croissances ou report de couche de ces différentes structures perturbe également les mesures. Ceci rend difficile l'adaptation des méthodes de mesure de durée de vie classiques comme, par exemple, le déclin de photoconductivité. Au cours de cette thèse nous nous sommes attachés à adapter des techniques de caractérisation de durée de vie à des matériaux de faibles dimensions. Nous avons tout d'abord caractérisé des échantillons massifs et des couches épitaxiées d'une épaisseur de l'ordre de la dizaine de micromètres. Nous avons proposé une technique qui consiste à déterminer simultanément la durée de vie en volume et la vitesse de recombinaison en surface des porteurs minoritaires dans d'une couche épitaxiée, à partir de la mesure de l'intensité de photoluminescence. La méthode développée consiste à calculer le rapport de l'intensité de photoluminescence (RPL) mesurée à différentes longueurs d'onde et pour différentes puissances d'excitation. Ces rapports RPL expérimentaux sont ensuite comparés aux rapports RPL simulés, ce qui permet d'évaluer la vitesse de recombinaison en surface et le temps de vie en volume. Nous avons ensuite étudié des couches semi-conductrices ultraminces de l'ordre de la centaine de nanomètres dans des structures de type SOI (silicon on insulator). Après un rappel des méthodes de fabrication et de quelques-unes des utilisations, nous avons analysé les méthodes électriques existantes permettant de déterminer la qualité des substrats SOI. Cela nous a amené à proposer une nouvelle méthode de caractérisation apportant des solutions aux limitations de ces techniques. Cette méthode se base sur une mesure courant-tension sous obscurité et sous éclairement en configuration PSEUDO-MOSFET où le substrat de la structure SOI sert de grille du transistor et deux pointes déposées sur le film de silicium servent de source et drain. Nous avons appliqué cette nouvelle méthode de caractérisation de la durée de vie des porteurs de charge à un substrat SOI et avec l'aide de la simulation numérique, nous avons pu expliquer les phénomènes de recombinaison aux interfaces et extraire les paramètres associés. Enfin, la dernière partie de ce travail de thèse concerne l'étude des nanofils pour des applications photovoltaïques. Dans les nanofils, le rapport surface sur volume augmente considérablement ce qui entraîne une diminution de la durée de vie effective due à l'augmentation de l'influence des surfaces. Le fonctionnement des cellules solaires à base de nanofils que nous avons étudiées est très dépendant de la qualité des interfaces. Nous avons analysé ces cellules grâce à la méthode RRT (« Reverse Recovery Transient ») basée sur la proportionnalité qui existe entre la quantité de charges stockées dans les régions neutres des jonctions pn polarisées et la durée de vie des porteurs minoritaires. Ce type de structure étant assez complexe, nous avons utilisé des simulations numériques pour analyser les phénomènes de recombinaison au sein de la cellule solaire et extraire les densités de défauts aux interfaces. / The minority carrier lifetime is one of the main parameters used to analyse the semiconductors quality and photoconductivity decay (PCD) is one of the most widely used lifetime characterization method. Thanks to the variety of automated equipment that has developed, lifetime measurement has become a routine technique to assess the quality of semiconductors. However, the micro and nano materials used in the photovoltaic and microelectronics industry require an adaptation of the existing methods (PCD, photoluminescence etc.). Indeed, with reduced dimensions (epitaxial layers, SOI “Silicon on Insulator”, nanostructures and nanowires), the influence of the surface (interface states density, traps, etc.) becomes predominant. The presence of the substrates used for the material growth or for the layer transfer can also influence the measures. Consequently traditional methods of lifetime measurement are difficult to apply to low dimensional materials. This thesis is focused on the measurement of minority carrier lifetime in micro and nano materials (bulk, epitaxial layer, silicon on insulator and nanowires) with a special emphasis on the adaptation of the characterization tools to the material thickness. We have studied first bulk samples and epitaxial layers (with thicknesses around 50µm) by photoluminescence. We have developed a method to determine simultaneously the bulk lifetime and the surface recombination velocity using room temperature photoluminescence measurement. The procedure consists in measuring the photoluminescence intensity ratio at different incident laser wavelengths and power. These photoluminescence ratios are then compared with analytical simulations, which allow us to evaluate the surface recombination velocity and the bulk lifetime. We have then investigated SOI (Silicon on insulator) structures with ultrathin semiconductor layers of the order of 100 nanometers. After a brief description of the manufacturing methods and of some of their uses, we have analyzed the existing electrical methods used to evaluate the quality of SOI substrates. This led us to propose a new characterization method to overcome the limitations of these techniques. This method is based on a current-voltage measurement in the dark and under illumination called PSEUDO-MOSFET (the substrate of the SOI structure serves as the transistor gate and the two contact points deposited on the silicon film are used as the source and drain). We applied this new method to characterize the lifetime of a SOI substrate and with the help of numerical simulation, we were able to explain the recombination mechanism associated with interfaces and extract the parameters. Finally, the last chapter concerns the study of nanowires for photovoltaic applications. In the nanowires, the surface to volume ratio greatly increases leading to a decrease of the effective lifetime due to the increased influence of the surfaces. In this chapter, we have studied the minority carrier lifetime in core-shell nanowire-based solar cells under dark conditions with a purely electrical approach called reverse recovery transient (RRT). This method is based on storage time measurement which depends essentially on the amount of stored charges in the biased junction and can be used to calculate the minority carrier lifetime. Numerical simulations have also been done to explain the measurements and to validate the theory and the hypotheses used for parameter extraction.
389

Identificação e análise de fontes de resiliência e fragilidade em empresas de táxi aéreo: estudo de múltiplos casos

Carim Júnior, Guido Cesar January 2010 (has links)
A Engenharia de Resiliência (ER) é um novo paradigma para gestão da segurança o qual, apesar de possuir uma fraca estrutura teórica, vem sendo aplicado em diversos setores. Neste contexto, este trabalho tem como objetivo a identificação de fontes de fragilidade e resiliência em empresas de táxi aéreo. Para essa identificação foram utilizados os seguintes princípios da ER: flexibilidade, consciência, aprendizagem e comprometimento da alta direção. O estudo de caso foi à estratégia de pesquisa adotada, tendo sido investigadas duas empresas de táxi aéreo de pequeno porte. O método de pesquisa envolveu as seguintes etapas: (a) caracterização da empresa sob a perspectiva de três subsistemas que compõem seu sistema sócio-técnico (social, técnico e organização do trabalho); (b) identificação dos constrangimentos e adaptações dos funcionários no desempenho de suas atividades; (c) identificação das fontes de fragilidade e resiliência a partir dos 4 princípios da ER, desdobradas em evidências empíricas conforme a literatura Os resultados mostram que 11 fontes estavam relacionadas à fragilidade da empresa A e 6 da empresa B. Da mesma forma, identificou-se 9 fontes de resiliência na empresa A e na empresa A. Em particular, o objetivo primário da empresa (lucro, no caso de uma das empresas; servir aos proprietários, no caso da outra empresa) revelou-se como uma fonte comum a todas as fontes de resiliência ou fragilidade e quase todas as fontes de resiliência constituíram de ações isoladas dos operadores, revelando a emergência dessas fontes na organização informal das empresas. / Resilience Engineering (RE) is a new safety management paradigm which, in spit of its weak theoretical structure, has been applied in many domains. In this context, this research has a main objective of identifying sources of brittleness and resilience on air taxi carriers. To accomplish this objective, this work used as base the following RE principles: flexibility, conscious, learning, top management commitment. Case study was the research strategy used, which investigated two small air taxi carriers. Research method involved the following steps: (a) air taxi carrier characterization from the tree subsystems that compose socio-technical system (social, technical, work system); (b) employees constraints and adaptations identification during the job; (c) brittleness and resilience source identification from 4 RE principles, unfolded in empirical evidences according to literature. The results show that 11 sources were related to brittleness at company A and 6 at company B. At the same way, 9 sources of resilience were identified at company A and company B. In particular, the main air taxi carrier objective (to profit, in of one them; to serve, to another one) appeared as a common to all sources of brittleness and resiliencies and almost all sources of resilience were constituted of isolated action from operators, revealing resilience source emergence from companies informal organization.
390

CO₂-Laser Induced Hot Electron Magneto-Transport Effects in n-InSb

Moore, Bradley T. 08 1900 (has links)
The effects of optical heating via infrared free carrier absorption on the electron magneto-transport properties of n-InSb at helium temperatures have been studied for the first time. Oscillatory photoconductivity (OPC) type structure is seen in the photon energy dependence of the transport properties. A C0₂ laser (hω = 115 to 135 meV) was used as the optical source. Concentrations between 1 x 10¹⁵ cm⁻³ and 2 x 10¹⁶ cm⁻³ were studied. The conclusions of this study are that the energy relaxation of high energy photoexcited electrons, generated by free carrier absorption of C0₂ laser radiation in degenerate n-InSb at liquid helium temperatures, is by emission of a maximum number of optical phonons, and that this relaxation mechanism produces OPC type structure in the photon energy dependence of the electron temperature of the conduction band electron gas. This structure is seen, therefore, in the transport properties of the sample, including the Shubnikovde Haas effect, the effective absorption coefficient, and the photoconductivity (mobility) response (lower concentrations only). In addition, the highest concentration studied, nₑ = ~2 x 10¹⁶ cm⁻³, sets an experimental lower limit on the concentration at which electron-electron scattering will become the dominant energy relaxation mechanism for the photoexcited electrons, since OPC effects were present in this sample.

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