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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.
61

In-Vitro Drug Delivery and Corrosion Study of Polymer Coated Nitinol Stents

Tan, Aoyong 28 April 2021 (has links)
No description available.
62

Identifying New Customers Using Machine Learning : A case study on B2B-sales in the Swedish IT-consulting sector / Identifiering av nya kunder med hjälp av maskininlärning : En fallstudie om B2B-försäljning i den svenska IT-konsultsektorn

Norlin, Patrik, Paulsrud, Viktor January 2017 (has links)
In this thesis, we examine machine learning as a tool for predicting new cus- tomers in a B2B-sales context. Using only publicly available information, we try to solve the problem using two different approaches: 1) a naive clustering based classifier built on K-means and 2) PU-learning with a random forests- adapter. We test these models with different sets of features and evaluate them using statistical measures and a discussion of the business implications. Our main findings conclude that the PU-learning could produce results that are satisfactorily for the purpose of improving the sales process, with the best case of being 4.8 times better than a random baseline classifier. However, the clustering based classifier was not good enough, producing only marginally better results than a random classifier in its best case. We also find that us- ing more variables improved the models, even in high-dimensional spaces with over 60 variables.
63

Managing the implementation of sustainable polyurethane (PU) coating for functional wear

Tasnime, Zarin, Buckley, Christine January 2023 (has links)
The purpose of this study is to explore the practical implementation of a commercially available sustainable alternative to conventional polyurethane (PU) textile coating for functional outerwear garments with protection from rain and snow. In addition, this study will identify the key consideration areas which should be taken into account during the managerial decision-making process of implementing the sustainable PU coating. This study employed an exploratory research design which used both quantitative and qualitative research methods to support in answering the research questions. The qualitative and quantitative research methods were applied respectively through semi-structured interviews and sample development trials. The research design began with a systematic literature review (SLR), then semi-structured interviews were conducted prior to sample development, then an experimental sample development was conducted, and lastly, additional semi-structured interviews were conducted subsequent to sample development. The findings revealed that the key consideration areas which should be taken into account during the managerial decision-making process of implementing a sustainable PU coating include chemical sustainability, legislative regulations, supplier capabilities, product quality and performance, purchase price, and lead time. Water-based PU coating was identified as a viable sustainable alternative to conventional PU coating for the application on textiles. Out of the three selected chemical suppliers, chemical supplier 1 was recommended by the researchers to the collaborating Swedish fashion brand as they were successful in producing a water-based PU coating which fulfilled all performance and key consideration area requirements. This research study contributes to furthering the development of water-based PU coating in the textile and apparel industry by developing a comprehensive implementation process from a practical managerial perspective.
64

The Transcription Factor PU.1 is Enriched At Inflammatory Bowel Disease Risk Loci in CD56+ Cells

Yaqoob, Fazeela January 2017 (has links)
No description available.
65

The Importance of Maintaining PU.1 Expression Levels During Hematopoiesis

Houston, Isaac Benjamin 08 October 2007 (has links)
No description available.
66

Processing and Properties of SBR-PU Bilayer and Blend Composite Films Reinforced with Multilayered Nano-Graphene Sheets

Holliday, Nathan 28 June 2016 (has links)
No description available.
67

Development of Applicable Benchmark Experiments for (Th,Pu)O2 Power Reactor Designs Using TSUNAMI Analysis

Langton, Stephanie E. January 2013 (has links)
<p>When simulating reactor physics experiments, uncertainties in nuclear data result in a bias between simulated and experimental values. For new reactor designs or for power reactor designs the bias can be estimated using a set of experiments. How- ever, the experiments used to estimate the bias must be applicable to the power reactor design of interest. Similarity studies can be performed to ensure this is the case. Here, potential experiments in the ZED-2 heavy water critical facility at Chalk River Laboratories were developed that would be applicable to the multiplication factor bias calculation of three thoria plutonia fuelled power reactor designs. The power reactor designs that were analyzed were the CANDU 6 with 37-element fuel bundles and 43-element fuel bundles, and a Canadian SCWR design with 78- element fuel assemblies. The power reactors were simulated using the code package SCALE 6.1 under burnup conditions that were determined using the lattice code DRAGON 3.06H and the diffusion code DONJON 3.02A. The intermediate results from DRAGON and DONJON were used to compare the benefits of various reactor designs. Various critical core configurations were then simulated in the ZED-2 re- actor using the SCALE 6.1 package. The similarities between the potential ZED-2 reactor experiments and the power reactors were analyzed. These results were used to design a set of experiments having sufficiently high completeness that they can be used as part of a bias calculation using the generalized linear least squares method. To do so a methodology was developed to guide the experiment set design process in which the fuel type, lattice arrangements, and coolant type are modified and the effects on the sensitivity coverage analyzed. A set of six experiments was designed for which all of the power reactor designs had a completeness of 0.7 or higher.</p> / Master of Applied Science (MASc)
68

Développement de nouveaux organocatalyseurs pour la synthèse de polyuréthanes / Development of new organocatalysts for the synthesis of polyurethanes

Alsarraf, Jérôme 03 December 2012 (has links)
Depuis leur découverte dans les années 1930, les polyuréthanes (PU) ont connu un essor important et représentent aujourd’hui un marché supérieur à 10 millions de tonnes par an. Ces matériaux sont préparés par réaction de polyaddition d'un polyol sur un polyisocyanate en présence d’un catalyseur. Des complexes organométalliques, notamment à base d’étain, sont communément employés pour accélérer cette réaction. Cependant, leur toxicité et leur nocivité envers l’environnement vont prochainement conduire à leur interdiction. Dans le cadre d’un projet pluridisciplinaire, nos efforts se sont concentrés sur le développement de catalyseurs potentiellement plus respectueux de l’environnement. Nous avons tout d’abord réalisé un criblage d’organocatalyseurs pour la synthèse de carbamates. Cette étude préliminaire a mis en évidence l’efficacité des guanidines bicycliques telles que le 7-méthyl-1,5,7-triazabicyclo[4,4,0]déc-5-ène (MTBD). De nouveaux analogues du MTBD ont été préparés et utilisés comme catalyseurs pour la synthèse de PU. Une étude mécanistique a également été conduite. Elle a permis d’expliquer les comportements catalytiques contrastés d’espèces chimiques pourtant très proches, à l’image du MTBD, du TBD, du DBU et du DBN. Ces travaux ont notamment mis en évidence la nucléophilie du MTBD qui réagit avec deux équivalents d’isocyanate pour former des composés tricycliques originaux. Ces nouveaux hétérocycles présentent des propriétés attrayantes de catalyseurs à effet retard thermo-activables pour la synthèse de PU. / Polyurethanes (PU) constitute an important market, estimated around 10 wt% of the current synthetic polymer production. They are usually prepared by the most straightforward route involving the addition of polyols to polyisocyanates in the presence of a catalyst. Tin based organometallic complexes are the most active catalysts currently in use, but environmental concerns should lead in not too distant a future to a ban of these reagents. In the context of a multidisciplinary project, we focused our efforts on the design of environmentally more acceptable organocatalysts that could advantageously replace metal-based catalysts. A screening of organocatalysts was therefore carried out, from which bicyclic guanidines such as 7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD) emerged as the most efficient. New analogues of MTBD were prepared and successfully used as catalysts for the synthesis of PU. Mechanistic studies were also performed. The catalytic behaviour of structurally similar compound such as MTBD, TBD, DBU or DBN was rationalised. The nucleophilic reaction between MTBD and isocyanates was highlighted and original compounds in which two equivalents of isocyanate are incorporated onto the guanidine scaffold were isolated. These novel heterocycles exhibit appealing thermally-triggered delayed-action catalytic properties for the synthesis of PU.
69

Etude des équilibres de phases en fonction de la température dans le système UO2-PuO2-Pu2O3 pour les céramiques nucléaires aux fortes teneurs en plutonium / Study of phase equilibria in function of temperature in UO2-PuO2-Pu2O3 system for nuclear ceramics with high plutonium contents

Truphemus, Thibaut 28 February 2013 (has links)
Dans la section UO2-PuO2-Pu2O3, les équilibres de phases décrivent un domaine monophasé (U1-y,Puy)O2-x stable pour y<0,20 à 25°C et jusqu'à l'équilibre solide-liquide. Aux teneurs Pu supérieures, ils sont plus complexes avec l'apparition d'une démixtion et la précipitation de phase(s) additionnelle(s). L'objectif de la thèse a consisté à améliorer la représentation du système pour 0,15≤y≤0,65 et 25≤T(°C)≤1500.A 25°C, une lacune de miscibilité composée de deux phases (U1-y,Puy)O2-X a été observée pour y<0,45, dont l'une est de rapport Oxygène/Métal proche de la stœchiométrie et une autre très réduite. Pour la première fois, un domaine triphasé a été caractérisé à teneurs Pu supérieures avec deux phases (U1-y,Puy)O2-X de teneurs proches de y=0,45, et une phase (U1-y,Puy)2O3 comprenant une faible proportion d'uranium solubilisée.L'étude en fonction de la température a démontré que la température de démixtion augmente avec la teneur Pu. Plusieurs représentations ont été établies. A 200°C, les limites d'existence du domaine multiphasé évoluent peu par rapport à 25°C. A 400°C, la démixtion survient à une teneur Pu proche de 0,35, largement inférieure à celle suggérée par la littérature. A 600°C, les résultats précisent les équilibres de phases jusqu'alors très méconnus avec une démixtion apparaissant à partir de y=0,60.L'analyse microstructurale des échantillons a clairement démontré l'impact significatif de la démixtion sur le matériau se traduisant par des fissures au sein des échantillons, d'autant plus nombreuses que la teneur en Pu est élevée. / In the UO2-PuO2-Pu2O3 section, a monophasic (U1-y,Puy)O2-x domain is stable for y<0,20 at 25°C and up to solid-liquid equilibrium. At higher Pu content, phase equilibria are more unclear with a phase separation process. The main objective of this work consisted in upgrading the representation of this system for 0,15≤y≤0,65 and 25≤T(°C)≤1500.At 25°C, a miscibility gap composed by two different (U1-y,Puy)O2-X phases has been observed for y<0,45, with one very closed to stoichiometric state (Oxygen/Metal=2) and one other very reduced. For the first time, a triphasic domain has been characterized at higher Pu contents, with two (U1-y,Puy)O2-X phases near y=0,45 and one (U1-y,Puy)2O3 phase with a low U content inside. Concerning the study in function of temperature, we have demonstrated that phase separation temperature increase when Pu content grows. Several representations have been established. At 200°C, the representation is closed to that at 25°C. At 400°C, the phase separation have been specified at a lower Pu content than that of literature : y=0,35. At 600°C, our results have clarified the section, until then very unclear, with a phase separation appearing at y=0,60.The microstructural analysis has clearly demonstrated the significant impact of the phase separation on the material. Indeed many cracks have been observed in our samples, and quantity of these defects increases when Pu content grows.
70

Influence du potentiel d’oxygène sur la microstructure et l’homogénéité U-Pu des combustibles U1-yPuyO2±x / Influence of the oxygen potential on the microstructure and the homogeneity of fuel U-Pu : U1-yPuyO2±x

Cocollomb, Ségolène 02 December 2013 (has links)
Les phénomènes de diffusion se produisant lors du frittage des oxydes mixtes d’uranium et deplutonium (MOX) dépendent du potentiel d’oxygène de l’atmosphère du four, qui détermine lanature et la concentration des défauts ponctuels dans le matériau. Les travaux de thèse ont porté surune meilleure compréhension de l’influence du potentiel d’oxygène sur la densification, la formationde la solution solide et l’interdiffusion U-Pu lors du frittage des combustibles MOX. Pour cela, unlarge domaine de potentiel d’oxygène a été étudié, entre -600 et -100 kJ.mol-1 à 1700°C, afin demettre en évidence les différents mécanismes diffusionnels et leur impact sur la microstructurelorsqu’on s’éloigne de la composition stoechiométrique i.e. lorsque la concentration en défautsaugmente.Les études ont montré que plus le potentiel d’oxygène augmente, plus la densification du mélange70 % UO2+x + 30 % PuO2 s’effectue à basse température. Lors du chauffage, les oxydes de départ(UO2+x et PuO2-x) densifient dans un premier temps puis la solution solide se forme à une températureplus élevée d’environ 200°C. La solution solide apparaît à plus basse température quand le potentield’oxygène augmente, avec une cinétique de formation plus rapide. L’étude de l’interdiffusion U-Puindique qu’un traitement thermique avec un potentiel d’oxygène supérieur à -150 kJ.mol-1 à 1700°Cpermet d’obtenir un coefficient d’interdiffusion supérieur d’un à deux ordres de grandeur à ceuxobtenus entre -550 et -350 kJ.mol-1 à 1700°C et conduit donc à une homogénéisation U-Pu accrue.Cette étude permet de donner des recommandations sur le choix de l’atmosphère et de proposer uncycle de frittage optimisé en fonction de l’application ou de la caractéristique souhaitée. / Diffusion mechanisms occurring during the sintering of mixed uranium-plutonium oxides (MOX) areaffected by the oxygen potential of the atmosphere, as this latter imposes the nature and theconcentration of point defects in the material. This work is focused on a better knowledge of theinfluence of oxygen potential on densification, solid solution formation and U-Pu interdiffusionduring the sintering of MOX fuels. In this aim, a wide range of oxygen potential was studied, between-600 and -100 kJ.mol-1 at 1700°C, to highlight the various diffusional mechanisms and their impact onthe microstructure as oxygen deviates from stoichiometric composition and the defect concentrationincreases.As oxygen potential increases, the densification of the 70 % UO2+x + 30 % PuO2 mixture occurs at alower temperature. During the heating, the initial oxides (UO2+x et PuO2-x) densify first and then thesolid solution starts forming at about 200°C higher. The solid solution appears at a lowertemperature as the oxygen potential increases, with a faster kinetics of formation. The U-Puinterdiffusion study indicates that a heat treatment with an oxygen potential higher than -150kJ.mol-1 at 1700°C allows to obtain an interdiffusion coefficient higher by one up to two orders ofmagnitude compared with those obtained between -550 and -350 kJ.mol-1 at 1700°C and thereforeleads to an enhanced U-Pu homogenizationThis study enables to make recommendations on the atmosphere choice and to provide an optimizedsintering cycle depending on the desired application or required feature.

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