The development of Smart Grid and an increased emphasis on Wide Area Measurement, Automation, Protection and Control (WAMPAC) has lead to the substantial increase in the development and use of Synchrophasor Systems. The Department of Energy having realized its importance in the Power System has encouraged its deployment through the Smart Grid Investment Grant. With many utilities beginning to implement a large number of PMUs over their respective power systems, Phasor Data Concentrators (PDCs) play a crucial part in accurately relaying data from the point of measurement to the operators at the control center. The current Synchrophasor standard, IEEE C37.118-2005 covers adequately the steady state characterization of PMUs but does not specify requirements for PDCs. Having recognized the need for such a standard for PDCs, the North American Synchrophasor Initiative (NASPI) has developed a guide outlining some of its objectives, functions and tests requirements. Virginia Tech has developed a PDC Test System under these guidelines and as per the requirements of the PJM Synchrophasor Systems Deployment Project. This thesis focuses on the testing tools developed and the procedures implemented in the Virginia Tech PDC Test System. / Master of Science

Chemistry of intermetallic bonded diamond is studied. The impact resistance and energies of intermetallic bonded diamond is compared to current poly crystalline diamond compacts. IBD’s are found to have high standards of hardness and have more impact energies absorbed. Intermetallic bonded diamond composite comprises of diamond particles dispersed in Tungsten carbide using Nickel aluminide (Ni3Al) as binder. In previous research conducted on IBD’s, diamonds are successfully dispersed in intermetallic alloy of nickel aluminide and processed at 1350°C such that diamond particles remain intact without forming graphite. Composites are formed by milling, pressing the intermetallic binder and diamond particles and sintering at high temperature conditions.

Plasmacytoid dendritic cells (pDCs) are important in innate and adaptive immune responses against viral infections, producing remarkable levels of type I interferon as well as other immunomodulatory cytokines. In vitro, pDCs can control replication of human immunodeficiency virus (HIV). Following natural challenge with simian immunodeficiency virus (SIV), PDCs infiltrate the vaginal mucosa. Despite this, pDCs are unable to prevent systemic dissemination of virus. To understand pDC activation immediately following HIV exposure, cytokine production and maturation of pDCs in response to HIV and a variety of other stimuli was compared. PDCs were found to respond suboptimally to HIV compared to other stimuli, with delayed interferon-alpha production, delayed maturation, and decreased production of inflammatory cytokines. Furthermore, HIV induced inhibitory signaling pathways in pDCs, suggesting subversion of the pDC response by HIV. Finally, different stimuli induced different early and late cytokine profiles, highlighting the complex and stimuli-dependant nature of the pDC response.

Plasmacytoid dendritic cells (pDCs) are important in innate and adaptive immune responses against viral infections, producing remarkable levels of type I interferon as well as other immunomodulatory cytokines. In vitro, pDCs can control replication of human immunodeficiency virus (HIV). Following natural challenge with simian immunodeficiency virus (SIV), PDCs infiltrate the vaginal mucosa. Despite this, pDCs are unable to prevent systemic dissemination of virus. To understand pDC activation immediately following HIV exposure, cytokine production and maturation of pDCs in response to HIV and a variety of other stimuli was compared. PDCs were found to respond suboptimally to HIV compared to other stimuli, with delayed interferon-alpha production, delayed maturation, and decreased production of inflammatory cytokines. Furthermore, HIV induced inhibitory signaling pathways in pDCs, suggesting subversion of the pDC response by HIV. Finally, different stimuli induced different early and late cytokine profiles, highlighting the complex and stimuli-dependant nature of the pDC response.

Bioethanol, produced from organic waste as a second-generation biofuel, is an important renewable energy source. Here, recalcitrant carbohydrate sources, such as municipal and agricultural waste, and plants grown on land not suitable for food crops, are exploited. The thermophilic, Gram-positive bacterium Geobacillus thermoglucosidasius is naturally very flexible in its growth substrates and produces a variety of fermentation products, including lactate, formate, acetate and ethanol. TMO Renewables Ltd. used metabolic engineering to enhance ethanol production, creating the production strain TM242 (NCIMB 11955 ∆ldh, ∆pfl, pdhup). Ethanol yield has been increased to 82% of the theoretical maximum on glucose and up to 92% of the theoretical maximum on cellobiose. However, this strain still produces acetate, presumably derived from the overproduction of acetyl-CoA through the upregulated pdh gene encoding the pyruvate dehydrogenase complex. An alternative to the mixed fermentation pathway found in G. thermoglucosidasius is to introduce a homoethanologenic pathway. Yeast and a very limited range of mesophilic bacteria use the homoethanol fermentation pathway, which employs pyruvate decarboxylase (PDC) in conjunction with alcohol dehydrogenase (ADH), to convert pyruvate to ethanol. Despite extensive screening, no PDC has yet been identified in a thermophilic organism. Using the thermophile G. thermoglucosidasius as a host platform, we endeavoured to develop a thermophilic version of the homoethanol pathway for use in Geobacillus spp. This Thesis reports the in vitro characterization and crystal structure of one of the most thermostable bacterial PDCs from the mesophile Zymobacter palmae (ZpPDC) and describes strategies to improve expression of active PDC at high growth temperatures. This includes codon harmonization and the successful development of a PET (producer of ethanol) operon. Furthermore, ancestral sequence reconstruction was explored as an alternative engineering approach, but did not yield a PDC more thermostable than ZpPDC. In vitro ZpPDC is most active at 65°C with a denaturation temperature of 70°C, when sourced from a recombinant mesophilic host. Codon harmonization improved detectable PDC activity in G. thermoglucosidasius cultures grown up to 65°C by up to 42%. Pairing this PDC with G. thermoglucosidasius ADH6 produced a PET functional up to 65°C with ethanol yields of 87% of the theoretical maximum on glucose. This increase in yield at temperatures of up to 15°C higher than previously reported for any PDC expressed.

Since 2001 the top international Notebook PC brand firm, Dell, established their Research and Development Center (R&D Center), or called TDC (Taiwan Design Center), in Taiwan, other Notebook PC firms also set up R&D Centers in Taiwan to work closely with Taiwan Notebook PC ODMs. In 2006, Dell has already handed over all the consumer Notebook R&D teams to TDC in Taiwan. Hewlett-Packard (HP) established R&D center in Taiwan in 2002, it is called Product Development Center (PDC) and now has thousands of engineers. The major responsibility of R&D Centers in Taiwan is to cooperate with Notebook PC ODMs to develop and manufacture Notebook PCs. The purpose of this study is to understand how the R&D Center evaluates Notebook PC ODMs and what the key factors are for evaluation from the R&D perspective. This study is taken by the depth of literature review and expert interviews and used AHP to develop a model of the evaluation to select a Notebook PC ODM as the partner to develop a new Notebook PC and mass-produce the products after complete development and validation. On the other hand, it helps Notebook PC ODMs to understand the client's selection criteria and know what the weaknesses are to improve accordingly.

No description available.

Les nanostructures 1D d'AlN promettent des nouvelles applications dans la technologie des semi-conducteurs, des antennes optiques et des résonateurs nanomécaniques. Elles peuvent également aboutir à l'évolution de nouveaux composants d'instrumentation. Cette étude explore deux voies originales pour élaborer des nanofilaments d'AlN en procédant à la mise en forme par électrofilage couplée à un procédé d'élaboration de céramique. Deux stratégies d'élaboration peuvent être considérées selon que le système initial contient de l'oxygène ou non. La maîtrise des conditions de mise en forme (paramètres d'électrofilage) ainsi que l'optimisation des solutions utilisées (teneur en polymère et en précurseur) et des traitements thermiques, ont permis d'obtenir des filaments de taille submicronique (entre 100 nm et 400 nm), ainsi que des tubes d'une grande pureté chimique et stables sous air jusqu'à 550°C. Il est démontré que la qualité des nano-objets d'AlN dépend de leur méthode de fabrication. L'étude basée sur deux méthodes de fabrication, l'une sous air et l'autre sous atmosphère contrôlée, permet de présenter les avantages et les inconvénients de chacune de ces deux approches, la première étant dite « low-cost » par rapport à la seconde / One-dimensional (1D) AlN nanostructures promise the achievement of new applications in semiconductor technology, optical antennas and nanomechanical resonators. They can also lead to the development of new components for instrumentation. This study explores two original methods to elaborate AlN nanofilaments performing shaping by electrospinning, coupled to a process for producing ceramic. Two strategies can be developed depending on whether the initial system contains oxygen or not. The control of the conditions of shaping (electrospinning parameters) and the optimization of the used solutions (polymer content and precursor) and heat treatments, allowed the obtainment of submicron sized filaments (between 100 nm and 400 nm), as well as tubes with a high chemical purity, and stable in air up to 550 °C. It is demonstrated that the quality of the AlN nano-objects depends on their method of elaboration. The study of the two used methods, one in air and the other under controlled atmosphere, can show the advantages and disadvantages of each of these two approaches, the first being "low-cost" comparing to the second

Un nombre croissant d'observations suggèrent que les pDC sont fortement impliqués dans le cancer, car les pDC sont recrutés dans des tumeurs solides, tant chez les patients humains que chez les modèles murins et sont généralement en corrélation avec un mauvais pronostique. Les pDC infiltrant les tumeurs présentent souvent un phénotype immature et sont des pauvres producteurs de IFN-I, de cytokines et de chimiokines pro-inflammatoires en réponse à la stimulation TLR, contribuant à l'établissement d'un micro-environnement tumoral immunosuppresseur qui favorise la croissance tumorale. D'autre part, lorsqu'ils sont activés à l'intérieur de la tumeur, les pDC pourraient être capable de générer des réponses immunitaires antitumorales efficaces qui contribueraient à la régression tumorale. Ce double rôle de TA-pDC rend cette population cellulaire d'un grand intérêt pour être ciblée dans l'immunothérapie tumorale. Par conséquent, notre étude est centrée sur l'exploration du rôle de pDC dans l'orchestration des réponses immunitaires antitumorales, visant à déchiffrer les caractéristiques fonctionnelles de pDC dans le micro-environnement de la tumeur.Nos résultats montrent que les pDC sont recrutés dans le micro-environnement de la tumeur TC-1 et B16-OVA, et les pDC infiltrant les tumeurs dans les deux modèles de tumeurs présentent un profil d'activation et d'expression génique distinct par rapport aux pDC purifiés à partir de la rate naïve, ce qui suggère un effet du microenvironnement tumoral dans le phénotype et les fonctions de TC-1 et BDC-OVA infiltrant pDC. En fait, les facteurs solubles sécrétés par les cellules tumorales TC-1 et B16-OVA et présentes dans le micro-environnement de la tumeur sont capables d'affecter fortement les fonctions des pDC, notamment leur capacité à produire IFN-α après la stimulation TLR-9. Parmi les facteurs solubles présents dans le micro-environnement de la tumeur, nos résultats montrent que le TGF-β seul est capable de bloquer la production d'IFN-α, suggérant clairement une influence du TGF-β dans les mécanismes intracellulaires conduisant à la production d'IFN-I par pDC. En outre, notre étude révèle que les effets du TGF-β sur le pDC affectent aussi les capacités de production de l'IFN-I, mais aussi leur capacité à sécréter d'autres cytokines et chimiokines ainsi que leur phénotype. Enfin, l'étude de l'environnement tumoral TC-1 en l'absence de pDC démontre un rôle délétère de cette population dans la croissance de la tumeur et montre une fonction claire de pDC dans l'induction de réponses immunitaires anti-tumorales dépendantes de NK.Les résultats obtenus au cours de cette thèse de doctorat ont mis en évidence le rôle important de la PDC dans le contexte tumoral et ont permis une meilleure compréhension du ciblage de cette population cellulaire contre l'immunothérapie tumorale / A growing number of observations suggest that pDC are highly implicated in cancer, since pDC are recruited into solid tumors, both in human patients and in murine models and generally correlate with a poor clinical outcome. Tumor infiltrating pDC often exhibit an immature phenotype and are poor producers of IFN-I and pro-inflammatory cytokines and chemokines in response to TLR stimulation, contributing to the establishment of an immunosuppressive tumor microenvironment that promotes tumor growth. On the other hand, when activated inside the tumor, pDC could be able to generate efficient anti-tumor immune responses that would contribute to tumor regression. This dual role of TA-pDC renders this cell population of great interest to be targeted in tumor immunotherapy. Hence, our study is centered in exploring the role of pDC in the orchestration of anti-tumor immune responses, aiming to decipher functional characteristics of pDC within the tumor microenvironment. Our results show that pDC are recruited into the TC-1 and B16-OVA tumor microenvironment and tumor infiltrating pDC in both tumor models exhibit a distinct activation and gene expression profile as compared to pDC purified from naïve spleen, suggesting an effect of the tumor microenvironment in the phenotype and functions of TC-1 and B16-OVA infiltrating pDC. In fact, the soluble factors secreted by the TC-1 and B16-OVA tumor cells and present in the tumor microenvironment are able to greatly affect pDC functions, more importantly their ability to produce IFN-α following TLR-9 stimulation. Among the soluble factors present in the tumor microenvironment, our results show that TGF-β alone is able to impair the production of IFN-α, clearly suggesting an influence of TGF-β in the intracellular machinery leading to IFN-I production by pDC. In addition, our study reveals that the effects of TGF-β on pDC are broader affecting not only the IFN-I producing abilities, but also their capacity to secrete other cytokines and chemokines as well as their phenotype. Finally, the study of the TC-1 tumor environment in the absence of pDC demonstrates a deleterious role of this population in the tumor growth and shows a clear function of pDC in the induction of NK-dependent anti-tumor immune responses.The results obtained throughout this PhD thesis highlighted the important role of pDC in the tumoral context and allowed further insight in targeting this cell population to tumor immunotherapy

Ce travail de thèse a porté sur le développement de membranes céramiques pour la filtration de colloïdes issus de la corrosion dans le circuit primaire des REP. La voie des polymères précéramiques a été mise en œuvre par la synthèse d’un polyborocarbosilane (PBC) à partir d’allylhydridopolycarbosilane conduisant à une céramique de type SiBC. Des billes de PMMA mono disperses d’une taille de 1,5 et 0,3 µm ont été préparées pour servir d’agent porogène pour créer une porosité contrôlée. Des objets micro-cellulaires 3D de forme circulaire ont été élaborés par pressage uni-axial avec ajout de billes de PMMA commercial pour servir de support macroporeux. Une étude de cristallinité à haute température (> 1000 °C) a été réalisée, montrant son influence sur la stabilité du matériau. La couche sélective a été préparée par dip-coating à partir de différentes formulations de barbotine contenant du PBC et les billes de PMMA élaborées. La stabilité physico-chimique des supports micro-cellulaires a été étudiée grâce à des essais de vieillissement en micro-autoclave en milieu primaire simulé. La résistance à la filtration a été testée grâce à un essai sur un dispositif de filtration connecté à un moyen d’essai de laboratoire permettant de simuler les conditions des REP. / This work has been focused on the development of ceramic membranes for the filtration of colloids resulting from corrosion in the primary loop of PWR. SiBC ceramics were synthesized by the preceramic polymers route from a polyborocarbosilane (PBC) obtained from allylhydridopolycarbosilane. Single-dispersed PMMA beads with a size of 1.5 and 0.3 μm were prepared to be used as a porogen agent to lead to a controlled porosity of the selective layer. 3D micro-cellular objects with a circular shape were developed by uni-axial pressing with the addition of commercial PMMA beads to serve as a macroporous support. A crystallinity study at high temperature (> 1000 ° C) was carried out showing its influence on the stability of the material. The selective layer was prepared by dip-coating from various slurry formulations containing PBC and the prepared PMMA beads. The chemical and physical stability of the microcellular supports was studied by ageing tests in a simulated primary water chemistry. The filtration resistance was tested by means of tests on a filtration device connected to a laboratory loop which simulates the conditions of the PWRs.