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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.
21

Seleção de modelos através de um teste de hipótese genuinamente Bayesiano: misturas de normais multivariadas e hipóteses separadas / Model selection by a genuinely Bayesian significance test: Multivariate normal mixtures and separated hypotheses

Lauretto, Marcelo de Souza 03 October 2007 (has links)
Nesta tese propomos o Full Bayesian Significance Test (FBST), apresentado por Pereira e Stern em 1999, para análise de modelos de misturas de normais multivariadas. Estendemos o conceito de modelos de misturas para explorar outro problema clássico em Estatística, o problema de modelos separados. Nas duas propostas, realizamos experimentos numéricos inspirados em problemas biológicos importantes: o problema de classificação não supervisionada de genes baseada em seus níveis de expressão, e o problema da discriminação entre os modelos Weibull e Gompertz - distribuições clássicas em análise de sobrevivência. / In this thesis we propose the Full Bayesian Significance Test (FBST) as a tool for multivariate normal mixture models. We extend the fundamental mixture concepts to another important problem in Statistics, the problem of separate models. In both methods, we perform numerical experiments based on important biological problems: the unsupervised classification of genes based on their expression profiles, and the problem of deciding between the Weibull and Gompertz models - two classical distributions widely used in survival analysis.
22

Etude d’un système de stockage de chaleur thermochimique avec réacteur séparé / Design and analysis of a thermochemical heat storage process with separated reactor

Farcot, Lauren 09 March 2018 (has links)
Les systèmes de stockage thermochimique s’avèrent être de bonnes alternatives aux technologies actuelles pour le stockage saisonnier ou intersaisonnier de la chaleur, car l’énergie est stockée sous forme d’un potentiel chimique et donc, il n’y a pas de pertes thermiques pendant la durée de stockage. Un grand nombre d’études a été mené sur le développement de réacteurs thermochimiques intégrés au système de stockage, et peu d’étude ont été menées sur les technologies de réacteur séparé du réservoir de stockage. Ces dernières présentent cependant l’avantage, entre autres, de dissocier la puissance thermique du réacteur et la capacité de stockage de l’installation, ce qui permettrait d’augmenter la densité de stockage.Cette étude se penche sur le développement d’un réacteur thermochimique à lit mobile fonctionnant avec des sels hydratés sous air humide, adapté à des applications aux réseaux de chaleur. Un prototype de réacteur, développé et construit durant cette étude, a permis d’analyser le fonctionnement du réacteur. Cette étude a, entre autres, mis en évidence l’impact des passages préférentiels de l’air sur les performances du réacteur (température et puissance), ainsi que l’importance du titre de vapeur de l’air à l’entrée du réacteur sur ces performances. Il apparaît également que la circulation du solide abaisse sensiblement le point d’équilibre atteint par la réaction.De plus, deux modèles mathématiques ont été développés : un modèle analytique 1D et un modèle 2D prenant en compte les phénomènes de transfert de matière et de chaleur au sein de la zone réactive. Le modèle 2D, validé avec les résultats expérimentaux, a été exploité à l’aide du logiciel de simulation par éléments finis COMSOL Multiphysics afin de mener une étude théorique sur le fonctionnement et les performances du réacteur. Cette étude numérique a porté sur l’influence des conditions opératoires (débit et taux d’humidité de l’air, vitesse du solide) sur les performances et le rendement du système et a permis la comparaison des réacteurs à lit mobile par rapport aux réacteurs à lit fixes, communément développés pour des applications de stockage thermochimique. Cette étude a montré l’importance de la régulation de la vitesse du solide pour l’optimisation des performances du réacteur à lit mobile.L’ensemble de cette étude a permis de mettre en évidence les avantages et les limitations d’un réacteur à lit mobile pour des applications de stockage thermochimique / Thermochemical storage systems prove to be good alternatives to current technologies for seasonal or inter-seasonal storage of heat, because energy is stored as a chemical potential and therefore, there is no heat loss during the storage period. Nowadays, a large number of studies have been conducted on the development of thermochemical reactor integrated in the storage system, andlittle study has been conducted on reactor technologies separated from the storage system. The latter, however, have the advantage, among others, of separating the thermal power produced or consumed and the storage capacity of the installation, which would increase the storage density.This study investigates the development of a moving-bed thermochemical reactor operating with hydrated salts and humid air cross-flow, suitable for district heating applications. A reactor prototype, developed and built during this study, allowed to analyze the functioning of the reactor. This study has, among others, highlighted the impact of the preferential air flow path on the reactorperformances (temperature and power), as well as the importance of the air humidity at the reactor inlet on these performances.In addition, two mathematical models have been developed : a 1D analytical model and a 2D model taking into account the heat and mass transfer phenomena within the reactive area. The 2D model, validated with the experimental results, was exploited using the finite element simulation software COMSOL Multiphysics to conduct a theoretical study on the functioning and the performances of the reactor. This numerical study focused on the influence of operating conditions (air flow rate and moisture content, solid flow rate) on the performances and the efficiency of the system and allowed the comparison of moving bed reactor over fixed bed reactors, commonly developed for thermochemical storage applications. This study has shown the importance of solid velocity control for optimizing the performances of the moving bed reactor.This study has highlighted the advantages and limitations of moving bed reactors for thermochemical storage applications
23

Rättsenlighet och ansvarstagande i de ensamkommande flyktingbarnens asylprocess

Tanhan, Nagehan, Özer, Beatrix January 2007 (has links)
<p>Earlier this year the Swedish migration board gave a part of their responsibility for the separated children to those municipalities that have signed an agreement with them, so that the children can get the best handling of their matters and also to lift the heavy pressure of the Swedish migration board. Our aim in this paper is to see how this division is made and which areas of responsibility they have. We want to see how this process is being handled in relation to these children’s rights, the Convention on the Rights of the Child and the Swedish law. To get the best information possible we used a qualitative method. We have in this study used reports written by voluntary organizations and the Swedish migration board. We have also used a few laws and interviewed people that have a central position in handling separated children. The study has shown that the Swedish migration board and the municipalities do not always fulfill the demands that the Convention on the Rights of the Child and the Swedish law require.</p> / <p>Tidigare i år har en del av Migrationsverkets ansvar för de ensamkommande barnen förlagts till kommuner som har skrivit under ett avtal med verket. Detta för att dessa barn ska få den bästa möjliga hanteringen av sina ärenden och för att lyfta på trycket som finns hos Migrationsverket. Vi vill i denna uppsats se hur denna fördelning har gjorts och vilka ansvarsområden som tillhör de olika parterna. Vi vill se hur de sköter denna process i förhållande till barnens rättigheter, barnkonventionen och den svenska lagen. För att få den bästa möjliga informationen har vi använt oss av den kvalitativa metoden. I studien har vi utnyttjat tidigare rapporter från frivilligorganisationer och Migrationsverket, lagar och har även intervjuat personer som har en central roll i hanteringen av de ensamkommande barnen. Studien har visat att Migrationsverket och kommunerna inte alltid uppfyller alla de krav som barnkonventionen och den svenska lagen ställer på dem.</p>
24

Transdermal delivery of 5-Fluorouracil with PheroidTM technology / C.P. van Dyk

Van Dyk, Christina Petronella January 2008 (has links)
Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
25

Rättsenlighet och ansvarstagande i de ensamkommande flyktingbarnens asylprocess

Tanhan, Nagehan, Özer, Beatrix January 2007 (has links)
Earlier this year the Swedish migration board gave a part of their responsibility for the separated children to those municipalities that have signed an agreement with them, so that the children can get the best handling of their matters and also to lift the heavy pressure of the Swedish migration board. Our aim in this paper is to see how this division is made and which areas of responsibility they have. We want to see how this process is being handled in relation to these children’s rights, the Convention on the Rights of the Child and the Swedish law. To get the best information possible we used a qualitative method. We have in this study used reports written by voluntary organizations and the Swedish migration board. We have also used a few laws and interviewed people that have a central position in handling separated children. The study has shown that the Swedish migration board and the municipalities do not always fulfill the demands that the Convention on the Rights of the Child and the Swedish law require. / Tidigare i år har en del av Migrationsverkets ansvar för de ensamkommande barnen förlagts till kommuner som har skrivit under ett avtal med verket. Detta för att dessa barn ska få den bästa möjliga hanteringen av sina ärenden och för att lyfta på trycket som finns hos Migrationsverket. Vi vill i denna uppsats se hur denna fördelning har gjorts och vilka ansvarsområden som tillhör de olika parterna. Vi vill se hur de sköter denna process i förhållande till barnens rättigheter, barnkonventionen och den svenska lagen. För att få den bästa möjliga informationen har vi använt oss av den kvalitativa metoden. I studien har vi utnyttjat tidigare rapporter från frivilligorganisationer och Migrationsverket, lagar och har även intervjuat personer som har en central roll i hanteringen av de ensamkommande barnen. Studien har visat att Migrationsverket och kommunerna inte alltid uppfyller alla de krav som barnkonventionen och den svenska lagen ställer på dem.
26

The Self-Calibration Method for Multiple Systems at the CHARA Array

O'Brien, David P 07 May 2011 (has links)
The self-calibration method, a new interferometric technique using measurements in the K′-band (2.1 μm) at the CHARA Array, has been used to derive orbits for several spectroscopic binaries. This method uses the wide component of a hierarchical triple system to calibrate visibility measurements of the triple’s close binary system through quasi-simultaneous observations of the separated fringe packets of both. Prior to the onset of this project, the reduction of separated fringe packet data had never included the goal of deriving visibilities for both fringe packets, so new data reduction software has been written. Visibilities obtained with separated fringe packet data for the target close binary are run through both Monte Carlo simulations and grid search programs in order to determine the best-fit orbital elements of the close binary. Several targets, with spectral types ranging from O to G and luminosity classesfrom III to V, have been observed in this fashion, and orbits have been derived for the close binaries of eight targets (V819 Her B, Kappa Peg B, Eta Vir A, Eta Ori Aab, 55 UMa A, 13 Ceti A, CHARA 96 Ab, HD 129132 Aa). The derivation of an orbit has allowed for the calculation of the masses of the components in these systems. The magnitude differences between the components can also be derived, provided that the components of the close binary have a magnitude difference of Delta K < 2.5 (CHARA’s limit). Derivation of the orbit also allows for the calculation of the mutual inclination (Phi), which is the angle between the planes of the wide and close orbits. According to data from the Multiple Star Catalog, there are 34 triple systems other than the 8 studied here for which the wide and close systems both have visual orbits. Early formation scenarios for multiple systems predict coplanarity (Phi < 15 degrees), but only 6 of these 42 systems are possibly coplanar. This tendency against coplanarity may suggest that the capture method of multiple system formation is more important than previously believed.
27

Hydroxy cruciforms and bis(hydroxystyryl)benzenes: synthesis, structure, and photophysical properties of novel π-systems

McGrier, Psaras Lamar 15 June 2010 (has links)
This thesis examines the synthesis, photophysical properties, and sensory responses of hydroxy-substituted 1,4-distyryl-2,5-bis(arylethynyl)benzenes (Cruciforms, XFs). These two-dimensional cross-conjugated materials possess spatially separated frontier molecular orbitals (FMOs). This spatial separation allows the HOMO and LUMO to be addressed independently by analytes, which leads to significant changes in their absorption and emission. These properties allow XFs to be utilized for the detection of various analytes. These studies highlight the benefits of utilizing XFs for the development of advanced functional solid state materials for sensory applications.
28

Surface Roughness Effects on Separated and Reattached Turbulent Flows in Open Channel

Ampadu-Mintah, Afua 04 July 2013 (has links)
An experimental research was performed to study the effects of surface roughness on the characteristics of separated and reattached turbulent flows in an open channel. A backward facing step was used to induce flow separation. The rough surfaces comprised wire mesh grit-80 and sand grains of average diameter 1.5 mm. In each experiment, the Reynolds number based on the step height and freestream velocity of approach flow was fixed at 3240 and the Reynolds number based on the approach flow depth and freestream velocity was kept constant at 25130. Particle image velocimetry (PIV) technique was used to measure the flow velocity. The results showed that roughness effects on the mean and turbulent quantities are evident only in the recovery region. Moreover, roughness effects on the flow dynamics are dependent on the specific roughness element.
29

Transdermal delivery of 5-Fluorouracil with PheroidTM technology / C.P. van Dyk

Van Dyk, Christina Petronella January 2008 (has links)
5-Fluorouracil (5FU) is a pyrimidine analogue, indicated for the therapy of proliferative skin diseases such as actinic keratosis (AK), superficial basal cell carcinoma and psoriasis. It has also been used for the treatment of solid tumours like colorectal, breast and liver carcinomas for nearly 40 years. Although 5FU has always been administered parenterally and orally, metabolism is rapid and absorption is erratic. Several severe side-effects are also commonly associated with 5FU therapy, including myelosuppression, hand-foot syndrome and gastrointestinal effects. Seeing that 5FU is an important part of the treatment of several malignant and pre-malignant disorders, it would be advantageous to find a delivery route and delivery system that negate absorption and metabolic variation and decrease side-effects. The transdermal route provides a promising alternative to the above-mentioned conventional delivery routes, solving most of the problems associated with parenteral and oral administration. That being said, the formidable barrier situated in the skin is not easily breached. The stratum corneum, the outermost skin layer, is mostly lipophilic in nature, preventing hydrophilic molecules such as 5FU from entering. 5FU-containing creams and lotions are currently commercially available, but absorption is still very limited. The transdermal absorption from these formulations has been compared to that obtained with the use of new transdermal delivery vehicles, with the newer formulations proving to be promising. It was decided to entrap 5FU in a novel therapeutic system, in the form of the Pheroid™ system, to increase its transdermal penetration. Pheroid™ vesicles are stable spherical structures in a unique, emulsion-like formulation, and fall in the submicron range. The main components of the Pheroid™ system are the ethyl esters of the essential fatty acids linoleic acid and linolenic acid, as well as the cys-form of oleic acid, and water. The formulation is saturated with nitrous oxide (N20). Although Pheroid™ vesicles may resemble other lipid-based vehicles, such as liposomes and micro-emulsions, they are unique in the sense that they have inherent therapeutic qualities as well. The Pheroid™ formulation can be specifically manipulated to yield different types of vesicles, ensuring a fast transport rate, high entrapment efficiency, rapid delivery and stability of the delivery system for a specific drug. In this study, 5FU was entrapped in the Pheroid™ formulation. Transdermal permeation studies were then performed to evaluate the influence of this delivery system on the transdermal flux of 5FU. Vertical Franz diffusion cells were utilised to determine the transdermal penetration of 5FU. Only Caucasian female abdominal skin was used to minimise physiological variables. Diffusion studies were done over 12 hour periods, with the entire receptor phase being withdrawn at predetermined intervals. Samples were analysed using high performance liquid chromatography (HPLC), after which the cumulative concentration of active was plotted against time. The linear portion of this graph represents the flux of 5FU through the skin. It was found that there were differences in the results between formulations containing 5FU in a phosphate buffer solution (PBS)-based Pheroid™ and water-based Pheroid™, though the difference was not statistically significant. The 0.5 % 5FU in water-based Pheroid™ resulted in a significantly bigger yield than the control (1 % 5FU in water) as well as a significant difference to the 1 % 5FU in PBS-based Pheroid™ formulation. In general the water-based Pheroid™ formulations had greater average cumulative concentrations, yields and fluxes than the other formulations. The fluxes obtained with the water-based Pheroid™ formulations also correlated well with a previous study done by Kilian (2004). Thus it can be concluded that the Pheroid™ therapeutic delivery system enhances the transdermal penetration of 5FU. Water-based Pheroid™ formulations proved to be more effective than PBS-based Pheroid™ formulations. It can also be concluded that a 0.5 % 5FU in water-based Pheroid™ formulation can be used instead of a 1 % formulation, because there were no statistically significant differences between the two formulations. This would be advantageous - patient compliance can be enhanced because of a more tolerable formulation with fewer side effects, while manufacturing cost is lowered by using a lower concentration of active. It is recommended that some aspects of the study be investigated further to optimise the transdermal delivery of 5FU using the Pheroid™ therapeutic system. These aspects include optimising the composition of the Pheroid formulation, investigating the entrapment process of 5FU within Pheroid™ spheres, the influence of PBS and water as basis of the Pheroid™ formulation and the amount of 5FU remaining in the epidermis after the 12 hour period of the diffusion study. Keywords: 5-Fluorouracil, Franz diffusion cell, Heat separated epidermis, Skin penetration, Transdermal, Drug delivery system, Pheroid™ / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
30

Föräldrars upplevelse av insatsen föräldrakoordinator.

Aspén-Franzén, Annika January 2014 (has links)
Föräldrakoordination är en barnfokuserad alternativ konfliktlösningsmetod som praktiserats i Sverige sedan 2009. Denna intervjustudie har undersökt separerade föräldrars upplevelse av att få stöd i sitt föräldrasamarbete av en föräldrakoordinator. Intervjuer har genomförts med sju föräldrar som haft insatsen föräldrakoordinator under minst sex månader. Samtliga deltagande föräldrar har flera års erfarenhet av svårlösta konflikter med den andra föräldern och har tidigare provat andra former av konfliktlösningsinsatser. Resultaten visar att föräldrarna upplevt metoden som hjälpsam när det gäller att öka samarbetsförmågan, sänka konfliktnivån och förbättra barnens mående. Flertalet av de intervjuade föräldrarna beskriver att de upplevt att det framförallt varit hjälpsamt att få stöd med att strukturera kommunikationen dem emellan. Att ha tillgång till mer information om de gemensamma barnen har förbättrat såväl föräldraskapet som relationen till barnet. Att slippa sitta i gemensamma samtal, att få göra skriftliga överenskommelser och att föräldrakoordinatorn haft ett tydligt barnfokus i samtalen tas också upp som hjälpsamt. Föräldrarna beskriver att det för att nå dessa resultat är viktigt att föräldrakoordinatorn kan förhålla sig neutral i konflikten. / Parenting Coordination is a child-focused alternative dispute resolution approach practiced in Sweden since 2009. In this interview study separated parents experience of being supported in their parental cooperation by a parenting coordinator have been examined. Interviews have been conducted with seven parents who have had a Parenting Coordinator for at least six months. All participating parents have had several years of experience in an intractable conflict with the other parent, and has previously tried other forms of dispute solving measures. The results show that most parents have experienced that the method has been helpful when it comes to improving co-parenting skills, reducing conflict and improving the well-being of their children. The interviewed parents state that it has been most helpful to get support in structuring the communication with the other parent. Some say that having access to more information regarding common children improves parenting as well as the parent-child relationship. Not having to sit together in shared dialogue, getting help to make written agreements and the Parenting Coordinator having a clear child-focus in meetings are also addressed as helpful. Parents describe that in order to achieve said results it is important that the parenting-coordinator can remain neutral in the conflict.

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