Dissertations / Theses: 'HDVs'

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Ter, Vehn Anton. "Longitudinal Control Design for Autonomous HDVs." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-261709.

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Autonomous vehicles are evolving from a futuristic dream to current realityas technology becomes more and more mature. However, their presence on thehighways will demands precise control over lateral and longitudinal positioning.This thesis, completed at Scania Group AB in Södertälje, mainly focuses on thedesign of longitudinal controllers for trajectory tracking without compromisingalready mature control solutions. To this end, a virtual vehicle is created toextrapolate where the vehicle is supposed to be in time, and its position andvelocity are used as reference inputs. Then, two different control strategies (aPD controller and a lead compensator) based on position error and velocityerror are developed. A breaking algorithm is also developed to use servicebrakes on an Heavy-duty vehicle effectively. Numerical studies highlight thatthe proposed controllers exhibit excellent performance while tracking both positionand velocity trajectories. The proposed controllers are examined in threedifferent test cases: varying velocity, executing lane changes, and driving in anenvironment with significant changes in topology. In all test cases, the positionerror is less than 1m, while the velocity error is less than 0.5m/s. Comparedto the existing controller, developed in Scania Group AB, these controllers improvethe tracking performance significantly. Also, both controllers improverobustness against lateral changes and exogenous forces.
I och med att forskningen mot det första autonoma fordonet fortgår, såhar många komplexa problem fått lösningar och uppmärksamheten har väntsmot andra problem. Detta examensarbete, utfört på Scania gruppenAB i Södertälje,utforskade longitudinella regulatorer som minimerar positionsfel ochhastighetsfel för lastbilar, genom att implementera en två regulatorer i kaskad,en som styr på positionsfel och en som styr på hastighetsfel. Det autonoma fordonssystemetutnyttjade path following, vars system modifierades för att skapaett virtuellt fordon som följer hastighetsprofilen perfekt och möjlighetgör trajectorytracking istället. De två regulatorer som implementerades var en PDregulator samt en fasavancerade regulator. Regulatorerna utvärderades i treolika test: Varierande hastighet, byte at körfält samt körning på väg med varierandetopologi. En bromsalgoritm var även implementerad för att se till attbromsarna används sparsamt men effektivt. Resultatet blev att båda regulatorernaförsäkrade att lastbilen kan minimera felet i hastighet och position, medett största fel på 1m i position och 0.5m i hastighet i alla test. Regulatorernavar även robusta mot laterella förändringar samt utomstående krafter.

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Badia, Canal Jordi. "Fuel Saving Potentials of HDVs through Platooning based on Real GPS Traces." Thesis, KTH, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145341.

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In the last years, the increase of the fuel price and the need to reduce the greenhouse gas emissions have triggered the research on lowering the fuel consumption within the transport sector. The research not only involves the development of more efficient engines but also the exploration of new transportation paradigms. One promising approach is to create vehicle platoons, i.e. convoys of vehicles driving close to each other. Vehicles driving close behind benefit from the reduction of the air drag and hence their overall fuel consumptions are reduced. This work focuses on studying platoons of heavy-duty vehicles (HDVs). More specifically, the work analyzes real position data of an HDV fleet from one manufacturer. The objective is to determine the potentials to reduce the fuel consumption of the fleet through platoon formations, using low sampled GPS traces obtained from the fleet management system. Map matching and path inference algorithms have been developed to reconstruct the path of the vehicles on a given road network. The reconstructed paths are used to analyze the vehicles’ positions and inter-vehicle distances. Results show that the vehicles are widely spread. The average distance to the closest vehicle is greater than 20km, which limits the platoon opportunities. Although with limited platoon opportunities, potential fuel savings up to 0.14% of the whole fleet’s consumption have been obtained. Results suggest that fuel savings can be largely improved if the density of vehicles in the road network is increased.

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Silva, Fernández Simón Yeco. "Photometric Redshifts in the HDFS." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/133104.

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Magíster en Ciencias, Mención Astronomía
Se presenta fotometría óptica en 11 bandas medias a partir de observaciones realizadas con el telescopio de 2.2m en LSO (WFI) sobre un campo de ~30'×30' deg extendido en el Hubble Deep Field-South (EHDF-S), el cual es uno de los campos que contiene información en multibandas como parte del Multiwavelength Survey by Yale-Chile (MUSYC). Este campo tiene una gran cantidad de datos públicos y datos auxiliares en bandas UV, óptico, infrarrojo cercano e infrarrojo lejano. Se determinaron aperturas óptimas para fotometría de alta precisión para diversas fuentes y brillos. Se proporcionan incertezas en magnitud a través de una técnica mejorada que considera correlaciones a mayor y menor escala en el ruido. Se incluyen datos auxiliares en el óptico a partir del catálogo de MUSYC en bandas UBVRIz ' hasta una magnitud total de R=25 (AB), además de datos en infrarrojo cercano JHK de dos campos de 10 '× 10' deg con profundidades de J~22.5, H~21.5 y K~21 (5σ; Vega). Se creó un catálogo fotométrico de ~62.000 galaxias detectadas en la imagen BVR de MUSYC. Se miden redshifts fotométricos mediante el código EAzY y se compara con ~500 fuentes identificadas espectroscópicamente con la finalidad de probar la precisión y desempeño de los filtros en bandas medias. Los redshifts fotométricos resultaron más confiables para R<24 cuando la muestra contiene ~12.000 galaxias, particularmente en 0.1 < z < 1.2, región de sampleo en el óptico de características como el quiebre de Balmer. La precisión de los redshifts fotométricos en Δz/(1+z) es de 0.029, lo cual es comparable a estudios recientes con un mejoramiento del 20%. Estos valores se degradan en calidad para galaxias más débiles o cuando se utilizan menos bandas. Como demostración de la calidad de los resultados, se derivan tipos espectrales de las fuentes, luego se construyen funciones de luminosidad para comparar con trabajos similares, y así confirmar la fuerte dependencia de las SEDs con la densidad numérica de fuentes. Se incorporan datos observacionales en radio en el HDFS del Australia Telescopio Hubble Deep Field-South para estudiar en detalle su población. Este proyecto realizó observaciones en cuatro longitudes de onda, 20, 11, 6 y 3 cm y alcanza una sensibilidad en rms alrededor de 10 μJy para cada longitud de onda. Utilizando una muestra de 227 fuentes en radio seleccionadas, se realiza una clasificación detallada de la población en AGNs (-loud de radio (9%) y -quiet (46%)), galaxias con formación estelar (SFG; 39%), y galaxias normales (6%), usando los redshifts fotométricos, información en multibanda, un template combinado quasares, índices espectrales, las SEDs derivadas y la dependencia redshift luminosidad. Se confirman los resultados recientes sobre la disribución de AGNs y SFGs. Asimismo las LFs muestran consistencia para las fuentes en radio para z~1.0. Los resultados obtenidos siguen la tendencia de los trabajos previos de los últimos 4 a 5 años en la distribución de las fuentes de radio, y sugiere nuevas metodologías en torno a la caracterizacón la población en radio.

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Alzahrani, Ahmed. "The operational and safety effects of heavy duty vehicles platooning." UNF Digital Commons, 2019. https://digitalcommons.unf.edu/etd/881.

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Abstract Although researchers have studied the effects of platooning, most of the work done so far has focused on fuel consumption. There are a few studies that have targeted the impact of platooning on the highway operations and safety. This thesis focuses on the impact of heavy-duty vehicles (HDVs) platooning on highway characteristics. Specifically, this study aims at evaluating the effects of platooning of HDVs on capacity, safety, and CO2 emissions. This study is based on a hypothetical model that was created using the VISSIM software. VISSIM is a powerful simulation software designed to mimic the field traffic flow conditions. For model validity, the model outputs were compared with recommended values from guidelines such as the Highway Capacity Manual (HCM) (Transportation Research Board, 2016). VISSIM was used to obtain the simulation results regarding capacity. However, in addition to VISSIM, two other software packages were used to obtain outputs that cannot be assessed in VISSIM. MOVES and SSAM are two simulation software packages that were used for emission and safety metrics, respectively. Both software packages depended on input from VISSIM for analysis. It was found that with the presence of HDVs in the model, the capacity, the emission of CO2, and the safety of the roadway would improve positively. A capacity of 4200 PCE/h/ln could be achieved when there are enough HDVs in platoons. Furthermore, more than 3% of the traffic flow emission of CO2 reduction is possible when 100% of the HDVs used in the model are in platoons. In addition to that, a reduction of more than 75% of the total number of conflicts might be obtained. Furthermore, with the analysis of the full factorial method and the Design of Experiment (DOE) conducted by using Excel and Minitab respectively, it was possible to investigate the impact of the platoons’ factors on the highway parameters. Most of these factors affect the parameters significantly. However, the change in the desired speed was found to insignificantly affect the highway parameters, due to the high penetration rate. Keywords: VISSIM, MOVES, SSAM, COM-interface, HDVs, Platooning, Number of Conflicts

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Careres, Gutierrez Franco Jesus. "Towards an S3-based, DataNode-lessimplementation of HDFS." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291125.

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The relevance of data processing and analysis today cannot be overstated. The convergence of several technological advancements has fostered the proliferation of systems and infrastructure that together support the generation, transmission, and storage of nearly 15,000 exabytes of digital, analyzabledata. The Hadoop Distributed File System (HDFS) is an open source system designed to leverage the storage capacity of thousands of servers, and is the file system component of an entire ecosystem of tools to transform and analyze massive data sets. While HDFS is used by organizations of all sizes, smaller ones are not as well-suited to organically grow their clusters to accommodate their ever-expanding data sets and processing needs. This is because larger clusters are concomitant with higher investment in servers, greater rates of failures to recover from, and the need to allocate moreresources in maintenance and administration tasks. This poses a potential limitation down the road for organizations, and it might even deter some from venturing into the data world altogether. This thesis addresses this matter by presenting a novel implementation of HopsFS, an already improved version of HDFS, that requires no user-managed data servers. Instead, it relies on S3, a leading object storage service, for all its user-data storage needs. We compared the performance of both S3-based and regular clusters and found that such architecture is not only feasible, but also perfectly viable in terms of read and write throughputs, in some cases even outperforming its original counterpart. Furthermore, our solution provides first-class elasticity, reliability, and availability, all while being remarkably more affordable.
Relevansen av databehandling och analys idag kan inte överdrivas. Konvergensen av flera tekniska framsteg har främjat spridningen av system och infrastruk-tur som tillsammans stöder generering, överföring och lagring av nästan 15,000 exabyte digitala, analyserbara data. Hadoop Distributed File System (HDFS) är ett öppen källkodssystem som är utformat för att utnyttja lagringskapaciteten hos tusentals servrar och är filsystemkomponenten i ett helt ekosystem av verktyg för att omvandla och analysera massiva datamängder. HDFS används av organisationer i alla storlekar, men mindre är inte lika lämpade för att organiskt växa sina kluster för att tillgodose deras ständigt växande datamängder och behandlingsbehov. Detta beror på att större kluster är samtidigt med högre investeringar i servrar, större misslyckanden att återhämta sig från och behovet av att avsätta mer resurser i underhålls- och administrationsuppgifter. Detta utgör en potentiell begränsning på vägen för organisationer, och det kan till och med avskräcka en del från att våga sig helt in i datavärlden. Denna avhandling behandlar denna fråga genom att presentera en ny implementering av HopsFS, en redan förbättrad version av HDFS, som inte kräver några användarhanterade dataservrar. Istället förlitar sig det på S3, en ledande objektlagringstjänst, för alla dess användardata lagringsbehov. Vi jämförde prestandan för både S3-baserade och vanliga kluster och fann att sådan arkitektur inte bara är möjlig, utan också helt livskraftig när det gäller läs- och skrivgenomströmningar, i vissa fall till och med bättre än dess ursprungliga motsvarighet. Dessutom ger vår lösning förstklassig elasticitet, tillförlitlighet och tillgänglighet, samtidigt som den är anmärkningsvärt billigare.

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Caceres, Gutierrez Franco Jesus. "Towards an S3-based, DataNode-less implementation of HDFS." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291125.

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Abstract:

The relevance of data processing and analysis today cannot be overstated. The convergence of several technological advancements has fostered the proliferation of systems and infrastructure that together support the generation, transmission, and storage of nearly 15,000 exabytes of digital, analyzabledata. The Hadoop Distributed File System (HDFS) is an open source system designed to leverage the storage capacity of thousands of servers, and is the file system component of an entire ecosystem of tools to transform and analyze massive data sets. While HDFS is used by organizations of all sizes, smaller ones are not as well-suited to organically grow their clusters to accommodate their ever-expanding data sets and processing needs. This is because larger clusters are concomitant with higher investment in servers, greater rates of failures to recover from, and the need to allocate moreresources in maintenance and administration tasks. This poses a potential limitation down the road for organizations, and it might even deter some from venturing into the data world altogether. This thesis addresses this matter by presenting a novel implementation of HopsFS, an already improved version of HDFS, that requires no user-managed data servers. Instead, it relies on S3, a leading object storage service, for all its user-data storage needs. We compared the performance of both S3-based and regular clusters and found that such architecture is not only feasible, but also perfectly viable in terms of read and write throughputs, in some cases even outperforming its original counterpart. Furthermore, our solution provides first-class elasticity, reliability, and availability, all while being remarkably more affordable.
Relevansen av databehandling och analys idag kan inte överdrivas. Konvergensen av flera tekniska framsteg har främjat spridningen av system och infrastruk-tur som tillsammans stöder generering, överföring och lagring av nästan 15,000 exabyte digitala, analyserbara data. Hadoop Distributed File System (HDFS) är ett öppen källkodssystem som är utformat för att utnyttja lagringskapaciteten hos tusentals servrar och är filsystemkomponenten i ett helt ekosystem av verktyg för att omvandla och analysera massiva datamängder. HDFS används av organisationer i alla storlekar, men mindre är inte lika lämpade för att organiskt växa sina kluster för att tillgodose deras ständigt växande datamängder och behandlingsbehov. Detta beror på att större kluster är samtidigt med högre investeringar i servrar, större misslyckanden att återhämta sig från och behovet av att avsätta mer resurser i underhålls- och administrationsuppgifter. Detta utgör en potentiell begränsning på vägen för organisationer, och det kan till och med avskräcka en del från att våga sig helt in i datavärlden. Denna avhandling behandlar denna fråga genom att presentera en ny implementering av HopsFS, en redan förbättrad version av HDFS, som inte kräver några användarhanterade dataservrar. Istället förlitar sig det på S3, en ledande objektlagringstjänst, för alla dess användardata lagringsbehov. Vi jämförde prestandan för både S3-baserade och vanliga kluster och fann att sådan arkitektur inte bara är möjlig, utan också helt livskraftig när det gäller läs- och skrivgenomströmningar, i vissa fall till och med bättre än dess ursprungliga motsvarighet. Dessutom ger vår lösning förstklassig elasticitet, tillförlitlighet och tillgänglighet, samtidigt som den är anmärkningsvärt billigare.

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Wang, Xiaojing. "Cost- benefit Models for HDV Platooning." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200533.

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Bonds, August. "Hash-based Eventual Consistency to Scale the HDFS Block Report." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-222363.

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The architecture of the distributed hierarchical file system HDFS imposes limitations on its scalability. All metadata is stored in-memory on a single machine, and in practice, this limits the cluster size to about 4000 servers. Larger HDFS clusters must resort to namespace federation which divides the filesystem into isolated volumes and changes the semantics of cross-volume filesystem operations (for example, file move becomes a non-atomic combination of copy and delete). Ideally, organizations want to consolidate their data in as few clusters and namespaces as possible to avoid such issues and increase operating efficiency, utility, and maintenance. HopsFS, a new distribution of HDFS developed at KTH, uses an in-memory distributed database for storing metadata. It scales to 10k nodes and has shown that in principle it can support clusters of at least 15 times the size of traditional non-federated HDFS clusters. However, an eventually consistent data loss protection mechanism in HDFS, called the Block Report protocol, prevents HopsFS from reaching its full potential. This thesis provides a solution to scaling the Block Report protocol for HopsFS that uses an incremental, hash-based eventual consistency mechanism to avoid duplicated work. In the average case, our simulations indicate that the solution can reduce the load on the database by an order of magnitude at the cost of less than 10 percent overhead on file mutations while performing similarly to the old solution in the worst case.
Det distribuerade, hierarkiska filsystemet Apache HDFS arkitektur begränsar dess skalbarhet. All metadata lagras i minnet i ett av klustrets noder, och i praktiken begränsar detta ett HDFS-klusters storlek till ungefär 4000 noder. Större kluster tvingas partitionera filsystemet i isolerade delar, vilket förändrar beteendet vid operationer som korsar partitionens gränser (exempelvis fil-flytter blir ickeatomära kombinationer av kopiera och radera). I idealfallet kan organisationer sammanslå alla sina lagringslösningar i ett och samma filträd för att undvika sådana beteendeförändringar och därför minska administrationen, samt öka användningen av den hårdvara de väljer att behålla. HopsFS är en ny utgåva av Apache HDFS, utvecklad på KTH, som använder en minnesbaserad distribuerad databaslösning för att lagra metadata. Lösningen kan hantera en klusterstorlek på 10000 noder och har visat att det i princip kan stöda klusterstorlekar på upp till femton gånger Apache HDFS. Ett av de hinder som kvarstår för att HopsFS ska kunna nå dessa nivåer är en så-småningom-konsekvent algoritm för dataförlustskydd i Apache HDFS som kallas Block Report. Detta arbete föreslår en lösning för att öka skalbarheten i HDFS Block Report som använder sig av en hash-baserad så-småningom-konsekvent mekanism för att undvika dubbelt arbete. Simuleringar indikerar att den nya lösningen i genomsnitt kan minska trycket på databasen med en hel storleksordning, till en prestandakostnad om mindre än tio procent på filsystemets vanliga operationer, medan databasanvändningen i värsta-fallet är jämförbart med den gamla lösningen.

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Quilfen, Cyril. "Supercritical fluids synthesis, characterization and test of HDS catalysts : Assessment of criticality of metals contained in HDS catalysts." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0405/document.

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Dans un contexte environnemental où les législations concernant la teneur ensoufre présent dans les coupes pétrolières sont de plus en plus drastiques, le développementde nouveaux catalyseurs toujours plus actifs est donc nécessaire. Cette augmentation del´activité catalytique est possible à plusieurs niveaux dont, par exemple, par l´utilisation denouveaux procédés de synthèse tel que l´emploi de la voie fluides supercritiques. Dans unpremier temps, l´objectif est d´étudier les éléments utilisés pour préparer ces catalyseurs afind´avoir une vision plus large des réserves, des utilisations, des possibilités de substitutions…La criticité de ces éléments a donc été évaluée par le biais de plusieurs indicateurs. Dans unsecond temps, la compréhension de la synthèse de catalyseurs d´hydrodésulfuration (HDS) aété étudiée. Pour cela des expériences utilisant différents solvants et précurseurs métalliquesont été suivies via des analyses in situ Raman. Après avoir défini les résultats les plusprobants, le procédé de préparation de catalyseurs HDS assisté par le CO2 supercritique(scCO2) a été optimisé à travers une étude paramétrique. Pour cela, la température, lapression, le solvant d´imprégnation, le ratio entre CO2 et solvant d´imprégnation, le temps deréaction et le chargement en métaux ont été variés. Les matériaux obtenus ont ensuite étéfinement caractérisés (microscopie, DRX, Raman, ICP, microsonde) avant d´être activés parsulfuration et testés dans différentes réactions catalytiques (hydrogénation du toluène,hydrodésulfuration du dibenzothiophène et du 4,6-diméthyldibenzothiophène)
In an environmental context where legislations concerning the sulfur content in oilare increasingly drastic, the research for new and ever more active catalysts is necessary. Thisincrease of the catalytic activity is possible at several levels, for example, with the use of novelsynthetic processes such as the use of the supercritical fluids route. In a first stage, theobjective is to study the elements used to prepare these catalysts in order to have a broaderview of the reserves, the uses, the possibility of substitutions ... The criticality of these elementshas therefore been evaluated by means of several indicators. In a second stage, theunderstanding of the synthesis of hydrodesulfurization catalysts (HDS) was studied. For thispurpose, experiments using different solvents and metallic precursors were followed by in situRaman analyses. After defining the most convincing results, the process for preparing HDScatalysts assisted by supercritical CO2 medium (scCO2) was optimized through a parametricstudy. For this, temperature, pressure, impregnation solvent, ratio of CO2 to impregnationsolvent, reaction time and metal loading were varied. The materials obtained were thencharacterized (microscopy, DRX, Raman, ICP, microprobe) before being activated bysulfidation and tested in various catalytic reactions (hydrogenation of toluene,hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene)

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Hantzer, Sylvain. "Nouveaux matériaux pour la réaction d'hydrodésulfuration (HDS)." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37614274n.

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Hantzer, Sylvain. "Nouveaux materiaux pour la reaction d'hydrodesulfuration (hds)." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13120.

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Nouveau modele de phase active obtenu par interpretation des resultats de rmn du **(59)co et de microscopie electronique haute resolution pour des catalyseurs d'hydrotraitement a base de sulfure de molybdene et de cobalt. Application a d'autres systemes : nire, core, rhre et rhmo. Etude de l'empoisonnement par la porphyrine de catalyseur nimo/al::(2)o::(3)

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Silva, Ilana Mirian Almeida Felipe da. "Soroprevalência da infecção pelos vírus da hepatite B e D em dois municípios da região do Baixo Munim, Maranhão, Brasil." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/22/22133/tde-09012015-112522/.

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As hepatites virais são um grave problema de saúde pública no mundo e no Brasil Taxas variadas de prevalência em diferentes regiões e grupos populacionais têm sido encontradas no país. Além disto, o HDV foi recentemente identificado em uma população do Estado do Maranhão. Neste sentido, o presente estudo teve como objetivo investigar a soroprevalência para HBV e HDV e identificar fatores associados ao vírus da hepatite B, em uma população do Baixo Munim, região rura próxima aos Lençóis Maranhenses, com precário nível de desenvolvimento econômico e social. Em uma população composta de 30.000 indivíduos, obteve-se uma amostra representativa de 1.249 indivíduos residentes nos municípios de Axixá (n=482) e Morros (n=760). Os participantes foram entrevistados com relação a suas caraterísticas sociodemográficas e comportamentais e foram coletadas amostras para a detecção dos marcadores sorológicos: HBsAg, anti-HBc total, anti-HBs e anti HDV total. Para o processamento e análise dos dados, foi utilizado o programa System Requirements for SAS 9.2. Do total de participantes, com idade variando de um a 96 anos (média de 27,4 ± 20,1 anos), 56,2% eram do sexo feminino, sendo que 71,0% eram da cor parda, 63,6% tinham apenas o ensino fundamental e 52,2% viviam com renda abaixo de um salário mínimo. As principais ocupações eram estudantes, agricultores e pescadores. A prevalência global da infecção pelo HBV fo de 41,3% (IC 95%: 38,6 - 44,1). A taxa de indivíduos reativos para HBsAg foi de 0,3% e para o HBsAg associado ao anti-HBc total foi 1,4%, sendo que ambas situações representam infecção atual. A associação do anti-HBc com o anti-HBs indicativo de infecção pregressa, foi verificada em 26,2% dos indivíduos. A presença do anti-HBc isolado foi identificada em 13,4% dos entrevistados. A presença do anti HBs isolado, indicativo de imunidade obtida por vacina, foi encontrada em 26% da população estudada, enquanto que, a porcentagem de indivíduos suscetíveis (ausência de marcadores) foi de 32,7%. Apenas uma amostra, dentre os indivíduos HBsAg reativos, foi reagente ao HDV, representando uma prevalência do anti-HDV total de 4,8%. Com emprego de um modelo de análise multivariada foi identificada associação significativa entre a infecção para hepatite B, residir no município de Morros e ter idade superior a 20 anos. Estes dados epidemiológicos revelam importante índice de infecção pelo HBV e presença do HDV na área estudada, além de demonstrar vulnerabilidade da população com relação a HBV devido a presença de baixa imunidade vacinal e considerável número de indivíduos suscetíveis. Os resultados apontam a necessidade de intensificação de programas de educação em saúde e imunização para a hepatite B, visando, principalmente, a diminuição da chance de transmissão entre crianças e jovens, além da adoção de práticas de controle e monitoramento epidemiológico destas infecções na população estudada
Viral hepatitides are a severe public health problem around the world and in Brazil. Various prevalence rates have been found in different regions and population groups in the country. In addition, recently, HDV has been identified in a population from the State of Maranhão. In that sense, the objective in this study was to investigate the seroprevalence for HBV and HDV and to identify factors associated with the hepatitis B virus in a population from Baixo Munim, a rural region near Lençóis Maranhenses, with precarious economic and social development levels. In a population of 30,000 individuals, a representative sample of 1,249 individuals was obtained, living in Axixá (n=482) and Morros (n=760). The participants were interviewed with regard to their sociodemographic and behavioral characteristics and samples were collected to detect the serological markers: HBsAg, total anti-HBc, anti-HBs and total anti-HDV. To process and analyze the data, the software System Requirements for SAS 9.2 was used. Among the participants, whose ages ranged between one and 96 years (mean 27.4 ± 20.1 years), 56.2% were female, 71.0% mulatto, 63.6% had only finished primary education and 52.2% gained an income of less than one minimum wage. The main occupations were: students, farmers and fishermen. The global prevalence of infection by HBV was 41.3% (95% CI: 38.6 - 44.1). The rate of individuals reactive to HBsAg was 0.3% and for HBsAg associated with total anti-HBc 1.4%. Both situations represent current infection. The association between anti-HBc and anti-HBs, indicating earlier infection, was found in 26.2% of the individuals. The presence of isolated anti-HBc was identified in 13.4% of the interviewees. The presence of isolated anti-HBs, indicating immunity through vaccination, was found in 26% of the study population, while the percentage of susceptible individuals (absence of markers) corresponded to 32.7%. Only one sample among the HBsAg- reactive individuals was reactive to HDV, representing a total anti-HDV prevalence of 4.8%. Using a multivariate analysis model, a significant association was identified between infection by hepatitis B, living in Morros and being over 20 years of age. These epidemiological data reveal an important HBV infection rate and the presence of HDV in the study area, besides demonstrating the population\'s vulnerability to HBV due to the presence of low vaccination immunity and the considerable number of susceptible individuals. The results indicate the need to intensify health education programs and immunization to hepatitis B, mainly aiming to reduce the chance of transmission among children and young people, as well as to adopt control and epidemiological monitoring practices of these infections in the study population

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Magnusson, Andreas. "Evaluation on how to use SystemVerilog as a design and assertion language." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7682.

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SystemVerilog är det första design och verifieringsspråk som har standardiserats och dess syfte är att bemöta de krav som kommer med den komplexitet dagens chip har. SystemVerilog är en expansion till det hårdvarubeskrivande språket Verilog-2001 och det har en rad bra funktioner för både design och verifiering. För tillfället finns det dock ingen definition på vilka delar av språket som kan användas för konstruktion och verktygstillverkarna kan själva bestämma vad som kan användas för syntes. Detta medför att det finns skillnader vad beträffar vilka delar av språket som stöds. SystemVerilog har även en underklass som underlättar för skrivandet av avancerade assertions, SVA, som öppnar upp för möjligheten för en designer att funktionalitetsverifiera sin design på ett effektivt sätt. SVA bidrar till ökad observerbarhet i konstruktionen och möjliggör användandet av andra verifieringsmetoder som formell verifiering etc. Detta examensarbetes huvuduppgift är att ta reda på hur SystemVerilog kan användas som designspråk och att reda ut hur man kan använda SVA på befintlig VHDL-kod utan att modifiera koden. Andra avsikter med rapporten är att utvärdera mognadsgraden på de verktyg som används för design på avdelningen, med avseende på SystemVerilog, samt att se på skillnader ellan SystemVerilog jämfört med det renodlade verifieringsspråket ’e’.

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Musatoiu, Mihai. "An approach to choosing the right distributed file system : Microsoft DFS vs. Hadoop DFS." Thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-844.

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Context. An important goal of most IT groups is to manage server resources in such a way that their users are provided with fast, reliable and secure access to files. The modern needs of organizations imply that resources are often distributed geographically, asking for new design solutions for the file systems to remain highly available and efficient. This is where distributed file systems (DFSs) come into the picture. A distributed file system (DFS), as opposed to a "classical", local, file system, is accessible across some kind of network and allows clients to access files remotely as if they were stored locally. Objectives. This paper has the goal of comparatively analyzing two distributed file systems, Microsoft DFS (MSDFS) and Hadoop DFS (HDFS). The two systems come from different "worlds" (proprietary - Microsoft DFS - vs. open-source - Hadoop DFS); the abundance of solutions and the variety of choices that exist today make such a comparison more relevant. Methods. The comparative analysis is done on a cluster of 4 computers running dual-installations of Microsoft Windows Server 2012 R2 (the MSDFS environment) and Linux Ubuntu 14.04 (the HDFS environment). The comparison is done on read and write operations on files and sets of files of increasing sizes, as well as on a set of key usage scenarios. Results. Comparative results are produced for reading and writing operations of files of increasing size - 1 MB, 2 MB, 4 MB and so on up to 4096 MB - and of sets of small files (64 KB each) amounting to totals of 128 MB, 256 MB and so on up to 4096 MB. The results expose the behavior of the two DFSs on different types of stressful activities (when the size of the transferred file increases, as well as when the quantity of data is divided into (tens of) thousands of many small files). The behavior in the case of key usage scenarios is observed and analyzed. Conclusions. HDFS performs better at writing large files, while MSDFS is better at writing many small files. At read operations, the two show similar performance, with a slight advantage for MSDFS. In the key usage scenarios, HDFS shows more flexibility, but MSDFS could be the better choice depending on the needs of the users (for example, most of the common functions can be configured through the graphical user interface).

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Su, Shengchen. "Cellular Events During Coccidial Infection in Chickens." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/82505.

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Avian coccidiosis is caused by the intestinal protozoa Eimeria. The parasite's site of infection in the intestine is site specific. Eimeria acervulina mainly affects the duodenum, E. maxima the jejunum, and E. tenella the ceca. Lesions in the intestinal mucosa cause reduced feed efficiency and body weight gain in Eimeria-challenged chickens. My previous studies showed that the growth reduction may be due to changes in expression of digestive enzymes and nutrient transporters in the intestine. This can also lead to diminished intracellular pools of nutrients and inhibit pathogen replication. In this dissertation, further analysis of cellular events was performed. Expression of host defense peptides (HDPs), apoptosis and autophagy related genes were examined in Eimeria challenged broilers. The results showed that upon Eimeria infection, LEAP2 was consistently downregulated in the target tissues, while the avian beta-defensins (AvBDs) showed many variations in expression patterns. Downregulation of LEAP2 may be a mechanism for Eimeria to combat the host defense system, and to promote its survival inside the host cell. The in situ hybridization results showed that LEAP2 was expressed only along the villus in the small intestine and not in the crypt. This is the first time LEAP2 has been localized to epithelial cells of the chicken intestine. Eimeria infection can also induce an anti-apoptotic and anti-autophagy state in the host cells. This condition can be both favorable and unfavorable to parasite survival and replication inside the host cell. A comparison of gene expression between Ross and Eimeria resistant Fayoumi (line M5.1 and M15.2) chickens challenged with Eimeria maxima was conducted. The comparison among different lines of chickens showed differential gene expression patterns in lines with different resistance to Eimeria. The similar body weight reduction indicated that there may not be a significant Eimeria resistant line among the Ross, Fayoumi M5.1 and M15.2 birds. The interaction between Eimeria and the host cell is very complex. Studying the mechanisms behind the changes of gene expression during Eimeria infection may give rise to potential therapeutic targets of coccidiosis.
Ph. D.

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Cui, Xiaoyun. "Dynamics of histone modification in integration of metabolic activity and stress response." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS474.

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Le réchauffement climatique a des effets importants et coûteux sur le climat et la production agricole. Étant sessiles, les plantes ont développé des mécanismes complexes pour percevoir les variations de température et y répondre, ainsi que pour afficher des changements spécifiques dans leur morphologie ou leur développement. Cependant, on sait peu de choses sur le mécanisme de reprogrammation de l'expression génique de la chromatine lors de la réponse de la plante à une température ambiante élevée. Les enzymes de modification de la chromatine nécessitent des produits de métabolisme intermédiaire en tant que substrats ou cofacteurs. Par exemple, les histone acétyltransférases utilisent l’acétyl-CoA en tant que donneur pour l’acétylation de la lysine et les histones déméthylases nécessitent l’a-cétoglutarate (α-KG) en tant que cofacteur. Chez les plantes, l'acétyl-CoA cytosolique est produite par l'ATP-citrate lyase (ACL) et l'α-KG est produite par les isocitrate déshydrogénases (ICDH) par différentes voies métaboliques. Cependant, il reste à déterminer si les fluctuations métaboliques affectent l'activité des enzymes de modification de l'histone et régulent l'expression des gènes lorsque la température ambiante est élevée. Dans ma thèse, j'ai contribué à analyser le rôle des histone désacétylases HDA9, HDA15 et HDA19 d'Arabidopsis dans la réponse thermique des plantes et j'ai étudié l'effet des niveaux d'acétyl-CoA sur l'état d'acétylation des histones chez Arabidopsis et le rôle de la fluctuation de l'α-KG dans le contrôle Activité de la déméthylase JmjC et croissance de la plante et expression génique à température chaude. Dans la première partie de l’étude, des analyses génétiques et moléculaires ont montré que HDA9, HDA15 et HDA19 s’adressent à différents ensembles de gènes et jouent des rôles distincts dans la réponse à la chaleur. D'autre part, nous avons constaté que lorsque le ACL était surexprimé chez les mutants gcn5, le niveau de H3K27ac était augmenté. De plus, la surexpression des ACL complétait partiellement les phénotypes gcn5. Les résultats ont démontré un lien intrinsèque entre les fluctuations de l'acétyl-CoA et les niveaux d'acétylation de l'histone H3K27 chez les plantes. Dans la deuxième partie de ma thèse, nous avons montré que la perte d’ICDH cytosolique entraînait une augmentation des niveaux de H3K4me3 et une augmentation des phénotypes mutants du gène de la déméthylase H3K4me3, JMJ14. Les analyses génétiques ont suggéré que JMJ14 et JMJ15 (une autre déméthylase H3K4me3) fonctionnaient de manière redondante pour réguler l’expression et la croissance de gènes sensibles à la chaleur des plantes et indiquaient que la mutation de cICDH affectait principalement la fonction de JMJ15. Une analyse pangénomique a révélé le rôle essentiel de JMJ14 dans l'établissement de programmes d'activation et de répression géniques de la thermomorphogenèse des plantes. JMJ14 et JMJ15 ont directement réprimé un ensemble de gènes susceptibles de jouer un rôle négatif dans le processus. Les résultats ont montré que la fluctuation des taux de métabolites régulait l'activité de l'histone déméthylase et la réponse des plantes à la chaleur. Pris ensemble, les résultats mettent en évidence l'interaction entre le métabolisme, l'épigénétique et l'adaptation des plantes au changement de l'environnement ambiant
Global warming is having significant and costly effects on the climate and agricultural production. Being sessile, plants have evolved complex mechanisms to perceive and respond to temperature variation and display specific changes in their morphology or development. However, little is known on the chromatin mechanism of gene expression reprogramming during plant response to elevated ambient temperature. Chromatin modification enzymes require intermediary metabolism products as substrates or cofactors. For example, histone acetyltransferases use acetyl-CoA as a donor for lysine acetylation and histone demethylases require α-ketoglutarate (α-KG) as a cofactor. In plants, cytosolic acetyl-CoA is produced by ATP-citrate lyase (ACL) and α-KG is produced by isocitrate dehydrogenases (ICDH) in different metabolic pathways. However, it remains unclear whether metabolic fluctuation affects the activity of histone modification enzymes and regulates gene expression under elevated ambient temperature. In my thesis, I contributed to analyze the roles of Arabidopsis histone deacetylases HDA9, HDA15, and HDA19 in plant thermal response and I studied the effect of acetyl-CoA levels on histone acetylation status in Arabidopsis and the role of α-KG fluctuation in controlling JmjC demethylase activity and plant growth and gene expression under warm temperature. In the first part of the study, genetic and molecular analysis showed that HDA9, HDA15, and HDA19 target to different sets of genes and play distinct roles in responding to warm temperature. On the other hand, we found that when overexpressed ACL in gcn5 mutants, the H3K27ac level was increased. Additionally, ACL overexpression partially complemented the gcn5 phenotypes. The results demonstrated an intrinsic link between acetyl-CoA fluctuation and histone H3K27 acetylation levels in plants. In the second part of my thesis, we showed that loss of cytosolic ICDH resulted in increased H3K4me3 levels and enhanced mutant phenotypes of the H3K4me3 demethylase gene JMJ14. Genetic analysis suggested that JMJ14 and JMJ15 (another H3K4me3 demethylase) functioned redundantly to regulate plant thermal responsive gene expression and growth and indicated the cICDH mutation mainly affected JMJ15 function. Genome-wide analysis revealed an essential role of JMJ14 in establishing both gene activation and repression programs of plant thermomorphogenesis. JMJ14 and JMJ15 directly repressed a set of genes that are likely to play a negative role in the process. The results provided evidence that the fluctuation of metabolites levels regulates histone demethylase activity and plant response to warm temperature. Taken together, the results highlight the interplay between metabolism, epigenetics and plant adaptation to changing the ambient environment

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Pradeep, Aakash. "P2PHDFS: AN IMPLEMENTATION OF STATISTIC MULTIPLEXED COMPUTING ARCHITECTURE IN HADOOP FILE SYSTEM." Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/214757.

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Computer and Information Science
M.S.
The Peer to Peer Hadoop Distributed File System (P2PHDFS) is designed to store and process extremely large-scale data sets reliably. This is a first attempt implementation of the Statistic Multiplexed Computing Architecture concept proposed by Dr. Shi for the existing Hadoop File System (HDFS) to eliminate all single point failures. Unlike HDFS, in P2PHDFS every node is designed to be equal and behaves as a file system server as well as slave, which enable it to attain higher performance and higher reliability at the same time as the infrastructure up scales. Due to the data intensive nature, a full implementation of P2PHDFS must address CAP Theorem challenges. This MS project is only intended as the ground breaking point using only sequential replication at this time.
Temple University--Theses

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Bernard, Julia M., Amber Seidel, Mary Oglesby, and Colleen Pagnan. "Mothers in HDFS Academic Life: When Your Professional Life and Real Life Intertwine." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/5808.

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Saturnino, David. "Compréhension de la relation entre la structure physico-chimique et l’activité des catalyseurs d’HDS vieillis." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10070.

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L'hydrodésulfuration (HDS) est un procédé majeur du raffinage pétrolier pour enlever le soufre des charges, typiquement avec un catalyseur CoMoS/Al2O3. Pendant un cycle du procédé d'HDS, la désactivation du catalyseur est due à trois causes principales : dépôt de coke, dépôt de métaux et ségrégation de la phase active. L'objectif de ce travail a été l'étude de l'effet du cokage et modifications de la phase active sur la désactivation du catalyseur d'HDS (de type CoMoS/Al2O3) appliqué à l'HDS des gazoles et la recherche des paramètres clés pour l'obtention d'un catalyseur usé comparable à celui issu de raffinerie. Des tests de vieillissement accéléré ont été réalisés avec différentes charges (différentes teneurs en aromatiques), couverture en hydrogène, durée et un pré-traitement de réduction. Après chaque test, les catalyseurs ont été caractérisés en termes de texture (méthodes BET et BJH), coke (Raman, IR, TPO, RPE, ToF-SIMS) et phase active (MET/EDX, XPS, TPR). En termes de texture et coke, une teneur élevée en aromatiques dans la charge et une couverture en hydrogène faible favorisent la formation de coke. Pour augmenter l'organisation du coke par rapport au catalyseur industriel, nous avons proposé un test plus long. En termes de phase active, une longue durée, couverture en hydrogène élevée et une pré-réduction favorisent plus d'hétérogénéité des teneurs en soufre et cobalt de la phase active et la formation d'agglomérats de sulfure de cobalt. La pré-réduction semble être efficace pour simuler l'exposition à des températures élevées pendant un cycle d'HDS, ce qui conduit à la ségrégation de la phase active, une caractéristique d'un catalyseur usé industriellement
Hydrodesulfurization (HDS) is a major process of petroleum refining for sulphur removal, where CoMoS/Al2O3 is the typical catalyst. During the cycle of a HDS process, deactivation of the catalyst is attributed to three main causes: coke deposition (with loss of pore volume), metals deposition and segregation of the active phase. The aim of this work was to study the effect of coking and active phase changes on the deactivation of the HDS catalyst (of CoMoS/Al2O3 type) applied to the HDS of a diesel feed and find the key operating conditions to obtain a spent catalyst comparable to the industrial one. Accelerated aging tests have been performed with different feedstocks (different amounts of aromatics), hydrogen to oil ratio, duration and a pre-reduction treatment. After each test, catalysts have been characterized in terms of texture (BET and BJH methods), coke (Raman, IR, TPO, EPR, ToF-SIMS) and active phase (TEM/EDX, XPS, TPR). In terms of texture and coke, a high amount of aromatics on the feedstock and low hydrogen to oil ratio favor the formation of coke. In order to increase the organization of graphitic coke, we have proposed a longer test. In terms of active phase, a long duration, high hydrogen to oil ratio and a pre-reduction treatment favor loss of dispersion of sulphur and cobalt contents of the active phase and formation of cobalt sulfide agglomerates. Pre-reduction seems to be an effective treatment to simulate the exposure to high temperatures during a HDS cycle which results in segregation of the active phase, a fingerprint of an industrial spent HDS catalyst

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Steiner, Esther Susanne. "OPAC 2.0 mit Web 2.0-Technologie zum Bibliothekskatalog der Zukunft? /." Stuttgart : Hochschule der Medien, 2007. http://opus.bsz-bw.de/hdms/volltexte/2007/624/pdf/steiner_bachelorarbeit.pdf.

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21

Abdou, Chekaraou Mariama. "Variabilité génétique des souches virales HBV et HDV circulant dans la région du Sahara en Afrique et étude de la co-spéciation HBV/HDV." Paris 13, 2010. http://www.theses.fr/2010PA132001.

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L’infection par le virus de l’hépatite B (HBV) constitue en Afrique Subsaharienne un problème de santé publique majeur. Le taux de prévalence de la protéine d’enveloppe du virus, l’antigène HBs (AgHBs) peut atteindre jusqu’à 30% dans certains pays. De plus on estime entre 70 à 100 millions le nombre de porteurs chroniques de l’HBV avec une fréquence de décès annuels de l’ordre de 250 000. Les données concernant l’infection concomitante par le virus de l’hépatite D (HDV) virus satellite de l’HBV, sont très rares car très peu d’études ont été conduites. Les génotypes HBV/E, et l’HBV/A ont été identifiés en Afrique subsaharienne, le génotype D étant cantonné à l’Afrique du Nord. De plus, plusieurs souches recombinantes entre le génotype E et les génotypes, A et D ont aussi été décrit. Concernant l’HDV, 4 génotypes « africains », HDV 5, -6, -7 et -8 ont été caractérisés au laboratoire chez des patients africains immigrés en France, infectés dans leur pays d’origine. Au cours de cette étude nous avons voulu déterminer l’épidémiologie moléculaire des souches HBV et HDV circulant au Niger, et plus généralement dans la région du Sahara (Mali de Mauritanie et du Tchad). Au partir d’une cohorte de donneurs de sang du Niger porteurs de l’AgHBs, nous avons retrouvé que 80% des souches étudiées appartenaient au génotype E. Ces souches présentaient une variabilité génétique significativement plus différente que celle décrite pour les souches HBV/E de la littérature (p<0,005) suggérant une diffusion plus ancienne de l’infection au Niger. De plus, nous avons mis en évidence un nouveau recombinant HBV/D-E entre des souches HBV/D et HBV/E, représentant près de 20% des souches isolées de notre cohorte, présentant des points de cassures précis, situés dans des « points chauds » de recombinaison décrits dans la littérature. Ce recombinant HBV/D-E présentait un taux de divergence dans sa séquence nucléotidique complète de plus de 4% en par rapport aux sous génotypes HBV/D décrits à ce jour. Les analyses phylogénétiques extensives effectuées nous permettent de le classer clairement comme un nouveau sous génotype, nous avons proposé HBV/D8. De même, comme décrits aussi par d’autres équipes, nous avons mis en évidence d’autres recombinants HBV-E/D, à la fois au Niger, mais aussi en Mauritanie avec des profils différents les uns des autres, témoignant de la grande variabilité génétique des souches virales dans la région. En revanche, la prévalence de l’infection Delta au Niger semblait a priori faible. Quatre souches de notre cohorte (7,8%), toutes de génotype HDV-1 ont été isolées. L’étude de la co-spéciation HBV/HDV dans cette région de l’Afrique saharienne (Niger, Mali de Mauritanie et du Tchad) a été entreprise à partir de 82 échantillons de la collection des sérums HDV positifs du laboratoire. Le génotype E était associé à tous les génotypes delta présents HDV-1, -5 et -7. De même, une souche HBV/D était aussi capable de s’associer à l’HDV-1 et -5. Afin de tester si l’enveloppement de HDV par HBV était dépendant ou non des génotypes des souches virales, nous avons mis au point un modèle cellulaire in vitro de co-transfection transitoire de plasmides codant la protéine AgHBs et la grande protéine delta. La méthode de mesure consistait en l’évaluation de la formation de particules pseudo-virales. Les résultats préliminaires obtenus à l’aide de HBV/D co-transfecté avec les génotypes HDV-1, HDV-3, HDV-5 et HDV-6 et HDV-7, montrent que HDV-1, mais pas HDV-5, était enveloppé. Grâce à ce modèle, les études seront poursuivies afin d’analyser la capacité d’enveloppement des différents « génotypes delta africains » par le génotype E
Infection with hepatitis B (HBV) in SubSaharan Africe is an issue of major public health. The prevalence of the envelope protein of the virus, HBs antigen (HBsAg) can reach up to 30% in some countries. In addition it is estimated between 70 to 100 million, the number of chronic carriers of HBV with an annual death rate of about 250 000. Data on coinfection with hepatitis D (HDV) virus satellite of HBV are very rare because very few studies have been conducted. In terms of molecular characterization of HBV and HDV circulating strains, studies, although partial and conducted with a small number of samples, have been reported. Two HBV genotypes, HBV/E, and HBV/A (with its sub genotypes A1, A2, A3, A4 and A5) have been mainly identified in sub-Saharan Africa. Genotype D is confined to North Africa. In addition, several recombinant strains between genotype E and genotypes A and/or D have also been described. Concerning the HDV, 4 "African genotypes", HDV-5, -6, -7 and -8 have been characterized in the laboratory from African patients immigrants in France, who had been infected in their country of origin. Two studies conducted in Gabon confirmed the presence of HDV genotype-7 and -8. In this study we wanted to determine the molecular epidemiology of HBV and HDV strains circulating in Niger and more generally in the Sahara region, in neighboring countries of Mali from Mauritania and Chad. In a cohort from blood donors in Niger HBsAg carriers, we found that 80% of the studied strains belonged to genotype E. These strains showed genetic variability significantly different from that described for HBV/E strains of the literature (p <0. 005) suggesting an ancient diffusion of infection in Niger. Furthermore, we identified a new recombinant HB /D-E between strains HBV/D and HBV / E, representing nearly 20% of strains isolated in our cohort, with the specific breakpoints located in hotspots recombination described elsewhere in the literature. The recombinant HBV/D-E showed a divergence in its complete nucleotide sequence of more than 4% as compared to HBV genotypes /D described to date. The extensive phylogenetic analyses carried out allow us to classify it as clear as a new genotype, we proposed HBV/D8. Similarly, as also described by other teams, we have highlighted other recombinant HBV/E-D, both in Niger, but also in Mauritania with profiles different from each other, reflecting the high genetic variability of viral strains in the region. In contrast, the prevalence of HDV infection in Niger seemed a priori low. Four strains in our cohort (7. 8%), all classified as genotype HDV-1 were isolated. The study of HBV / HDV co-speciation in this region of Saharan Africa (Niger, Mali, Mauritania and Chad) was undertaken from 82 samples from the laboratory collection of HDV positive serum. Genotype E was associated with all delta genotypes found, HDV -1, -5 and -7. Similarly, HBV/D strain was also able to envelope the HDV-1 and -5. To test whether the envelopment of HDV or HBV was dependent or not on genotypes of virus strains, we developed a cellular in vitro model of transient co-transfection of plasmids encoding the HBsAg protein and large delta protein. The measurement method consisted of evaluating the formation of viral like particles. Preliminary results obtained with HBV/D co-transfected with HDV-1, -3, -5, -6, and -7, showed that HDV-1, but not HDV-5, was wrapped. With this model, studies are continuing to analyze the ability of the genotype E to wrapping different "Delta African genotypes"

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22

Gong, Bo. "Raman spectroscopic studies of the hepatitis delta virus (HDV) ribozyme." Cleveland, Ohio : Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1228319219.

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Gong, Bo. "Raman spectroscopic studies of the hepatitis delta virus (HDV) ribozyme." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1228319219.

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24

Peiro, Sajjad Hooman, and Harirbaf Mahmoud Hakimzadeh. "Maintaining Strong Consistency Semantics in a Horizontally Scalable and Highly Available Implementation of HDFS." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127464.

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The Hadoop Distributed Filesystem (HDFS) is the storage layer of Hadoop, scaling to support tens of petabytes of data at companies such as Facebook and Yahoo. One wellknown limitation of HDFS is that its metadata has been stored inmemory on a single node, called the NameNode. To overcome NameNode’s limitations, a distributed file system concept based on HDFS, called KTHFS, was proposed in which NameNode’s metadata are stored on an inmemory replicated distributed database, MySQL Cluster. In this thesis, we show how to store the metadata of HDFS NameNode in an external distributed database while maintaining strong consistency semantics of HDFS for both filesystem operations and primitive HDFS operations. Our implementation supports MySQL Cluster, to store the metadata, although it only supports a readcommitted transaction isolation model. As a readcommitted isolation model cannot guarantee strong consistency, we needed to carefully design how metadata is read and written in MySQL Cluster to ensure our system preserves HDFS’s consistency model and is both deadlock free and highly performant. We developed a transaction model based on taking metadata snapshotting and the careful ordering of database operations. Our model is general enough to support any database providing at least readcommitted isolation level. We evaluate our model and show how HDFS can scale, while maintaining strong consistency, to terabytes of metadata.

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25

Gonzalez, Lorenzo Aldo. "Computational homology applied to discrete objects." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4073/document.

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La théorie de l'homologie formalise la notion de trou dans un espace. Pour un sous-ensemble de l'espace Euclidien, on définit une séquence de groupes d'homologie, dont leurs rangs sont interprétés comme le nombre de trous de chaque dimension. Ces groupes sont calculables quand l'espace est décrit d'une façon combinatoire, comme c'est le cas pour les complexes simpliciaux ou cubiques. À partir d'un objet discret (un ensemble de pixels, voxels ou leur analogue en dimension supérieure) nous pouvons construire un complexe cubique et donc calculer ses groupes d'homologie.Cette thèse étudie trois approches relatives au calcul de l'homologie sur des objets discrets. En premier lieu, nous introduisons le champ de vecteurs discret homologique, une structure combinatoire généralisant les champs de vecteurs gradients discrets, qui permet de calculer les groupes d'homologie. Cette notion permet de voir la relation entre plusieurs méthodes existantes pour le calcul de l'homologie et révèle également des notions subtiles associés. Nous présentons ensuite un algorithme linéaire pour calculer les nombres de Betti dans un complexe cubique 3D, ce qui peut être utilisé pour les volumes binaires. Enfin, nous présentons deux mesures (l'épaisseur et l'ampleur) associés aux trous d'un objet discret, ce qui permet d'obtenir une signature topologique et géométrique plus intéressante que les simples nombres de Betti. Cette approche fournit aussi quelques heuristiques permettant de localiser les trous, d'obtenir des générateurs d'homologie ou de cohomologie minimaux, d'ouvrir et de fermer les trous
Homology theory formalizes the concept of hole in a space. For a given subspace of the Euclidean space, we define a sequence of homology groups, whose ranks are considered as the number of holes of each dimension. Hence, b0, the rank of the 0-dimensional homology group, is the number of connected components, b1 is the number of tunnels or handles and b2 is the number of cavities. These groups are computable when the space is described in a combinatorial way, as simplicial or cubical complexes are. Given a discrete object (a set of pixels, voxels or their analog in higher dimension) we can build a cubical complex and thus compute its homology groups.This thesis studies three approaches regarding the homology computation of discrete objects. First, we introduce the homological discrete vector field, a combinatorial structure which generalizes the discrete gradient vector field and allows to compute the homology groups. This notion allows to see the relation between different existing methods for computing homology. Next, we present a linear algorithm for computing the Betti numbers of a 3D cubical complex, which can be used for binary volumes. Finally, we introduce two measures (the thickness and the breadth) associated to the holes in a discrete object, which provide a topological and geometric signature more interesting than only the Betti numbers. This approach provides also some heuristics for localizing holes, obtaining minimal homology or cohomology generators, opening and closing holes

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Lévesque, Michel. "Étude du ribozyme SOFA-HDV comme outil moléculaire : application et optimisation." Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6243.

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Les avancées en biologie moléculaire et cellulaire des dernières décennies ont permis de redéfinir le rôle de l’ARN au sein des cellules de tous les domaines du vivant. Initialement cantonné dans un rôle de support transitoire de l’information génétique du génome (ADN) en direction des effecteurs ou molécules actives (protéines et métabolites), l’ARN est maintenant associé à toutes les sphères de la biologie. Les molécules d’ARN peuvent agir autant comme génome (virus), comme molécules adaptatrices (ARNt), comme messager de l’information génétique (ARNm), comme enzyme (ribozyme) ou encore comme molécules régulatrices en cis (riboswitch) ou en trans (miARN). Nous savons aussi que la grande majorité du génome des cellules eucaryotes est transcrite à un moment ou un autre. Ces implications de l’ARN en font une cible de choix pour la recherche en génomique fonctionnelle, ainsi que pour des applications thérapeutiques. C’est pourquoi, depuis la découverte des ARN catalytiques et de l’interférence à l’ARN, beaucoup d’efforts ont été consacrés pour développer un éventail d’outils moléculaires permettant d’inhiber l’expression de gènes d’intérêt. Le défi qui se dessine aujourd’hui est le développement d’outils plus spécifiques et plus efficaces, entre autres parce que la variété d’ARN qu’un inhibiteur peut rencontrer est beaucoup plus grande qu’initialement estimée. De plus, les données recueillies lors d’essais cliniques montrent la nécessité de combiner un très grand potentiel avec une spécificité accrue. Les travaux de cette thèse se concentrent sur un outil moléculaire qui a le potentiel de répondre positivement à ce défi : le ribozyme SOFA-HDV. Mon projet de recherche visait à démontrer le potentiel de cet ARN catalytique pour le ciblage de gènes in cellulo et de développer son application. Tout d’abord, j’ai démontré que le ribozyme SOFA-HDV pouvait être utilisé pour inhiber la fonction d’un ARN in cellulo. Cette étude a également mis en évidence l’usage de ce ribozyme comme agent antiviral, avec le virus de l’hépatite C comme modèle. Le développement de nouvelles thérapies plus performantes avec peu d’effets secondaires demeure un enjeu important. Au moment de publier ces travaux, en plus d’être le premier exemple exhaustif de l’utilisation du ribozyme SOFA-HDV in cellulo, notre étude contenait le plus grand nombre de ribozymes jamais testés contre le VHC en une seule publication. Bien que modeste, l’effet observé démontre que ce ribozyme peut inhiber la réplication d’un virus dans un modèle in cellulo. Nos résultats exposent aussi la différence d’accessibilité entre les ARN de polarités positive et négative du VHC in cellulo. Par la suite, j’ai participé au développement de ribozymes SOFA-HDV ciblant le virus de l'immunodéficience humaine (VIH) dans le cadre d’une collaboration. Parmi les ribozymes testés, nous en avons identifié un dont l’activité catalytique réduit la réplication du VIH de plus de 50 % dans un modèle cellulaire. Dans le cadre de cette étude, nous avons identifié un site hautement favorable pour le ciblage par un ribozyme SOFA-HDV ou par un shARN. Des données suggèrent aussi une spécificité élevée du ribozyme SOFA-HDV. Des tests d’inhibition avec différentes souches du VIH montrent que l’activité du ribozyme est affectée avec un seul mésappariement entre le biosenseur (élément du module SOFA resposable de reconnaissance du substrat) et son site de liaison. Finalement, dans un esprit d’intégration des connaissances recueillies au fil des différents projets impliquant le ribozyme SOFA-HDV, je me suis intéressé à leur processus de sélection pour le ciblage génique. J’ai démontré l’impact de la séquence du biosenseur sur l’activité du ribozyme. J’ai également illustré l’autocoupure possible lorsque la séquence du biosenseur crée un prolongement du bloqueur (élément du module SOFA agissant comme verrou) ainsi que l’impact de la structure du substrat autant au niveau des sites de liaison du domaine de reconnaissance que du biosenseur. Ces nouveaux éléments combinés aux données antérieures sur le ribozyme HDV original m’ont permis d’élaborer une marche à suivre pour la présélection des ribozymes SOFA-HDV selon leur potentiel comme ciseaux moléculaires. En conclusion, ces travaux ont contribué à mettre de l’avant le potentiel du ribozyme SOFA-HDV pour des applications de ciblage de gènes, plus particulièrement pour des cibles virales. De ce fait, il existe maintenant des exemples concrets de l’utilisation de ce ribozyme en cellules humaines. Tout indique que la spécificité du module SOFA est préservée in cellulo et serait avantageusement comparable à d’autres technologies. Globalement, cette thèse devrait rendre l’utilisation du ribozyme SOFA-HDV plus accessible et favoriser son développement comme outil moléculaire.

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Hakimi, Amirmansoor. "Plasma protein profiling for bladder cancer biomarker discovery using UPLC-HDMS^E label-free quantitation." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28260.

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In the UK, bladder cancer is the 4th most common cancer in men and 11th most common in women. In 2010, just over 10,000 new cases were diagnosed and 4,900 deaths were recorded. At their first diagnosis, the majority of bladder cancer patients (75-85%) present with non-muscle invasive disease. In 50-70% of these patients the tumour will recur and in 10-20% of them it will progress to muscle invasive disease. Mass spectrometry based proteomics has been chosen for clinical biomarker discovery due to its ability to perform qualitative and quantitative protein profiling on clinical samples. In total 90 plasma samples were used in this study in two groups of disease and control. An optimised and evaluated UPLC-IMS-DIA-MS^E label-free quantitation method was used for plasma protein profiling. To our knowledge, this is the first report investigating the biomarkers of bladder cancer incorporating label-free quantitation and UPLC-IMS-DIA-MS^E methodology. To assess expression level of proteins of samples in different groups a plan consisting of four data processing packages was used. Each of the packages uses different statistical means by which to identify proteins and/or compare expression levels alteration. Optimisation of the methodology helped in the thorough investigation of the plasma proteome with coverage of up to five orders of magnitude of plasma protein concentration dynamic range. In total, 11 proteins were found as possible markers of diagnosis for bladder cancer. Four of these candidates (afamin, alpha 1-B-glycoprotein, apolipoprotein-A1 and haptoglobin) were previously reported to be urinary markers of bladder cancer. CRP was overexpressed when plasma samples from patients with low grade-Ta tumours were compared to every other sample and may be used as a diagnostic marker. Similarly, afamin and haptoglobin were overexpressed in plasma samples from patients with high grade-high stage tumours when compared to samples from patients with high grade-low stage disease.

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Thunmarker, Josefine. "Återställande efter avhjälpande enligt AB04 : Hur omfattande är ansvaret med hänsyn till HD:s nya tolkningsmodell?" Thesis, Umeå universitet, Juridiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-149833.

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Nyström, Simon, and Joakim Lönnegren. "Processing data sources with big data frameworks." Thesis, KTH, Data- och elektroteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188204.

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Big data is a concept that is expanding rapidly. As more and more data is generatedand garnered, there is an increasing need for efficient solutions that can be utilized to process all this data in attempts to gain value from it. The purpose of this thesis is to find an efficient way to quickly process a large number of relatively small files. More specifically, the purpose is to test two frameworks that can be used for processing big data. The frameworks that are tested against each other are Apache NiFi and Apache Storm. A method is devised in order to, firstly, construct a data flow and secondly, construct a method for testing the performance and scalability of the frameworks running this data flow. The results reveal that Apache Storm is faster than Apache NiFi, at the sort of task that was tested. As the number of nodes included in the tests went up, the performance did not always do the same. This indicates that adding more nodes to a big data processing pipeline, does not always result in a better performing setup and that, sometimes, other measures must be made to heighten the performance.
Big data är ett koncept som växer snabbt. När mer och mer data genereras och samlas in finns det ett ökande behov av effektiva lösningar som kan användas föratt behandla all denna data, i försök att utvinna värde från den. Syftet med detta examensarbete är att hitta ett effektivt sätt att snabbt behandla ett stort antal filer, av relativt liten storlek. Mer specifikt så är det för att testa två ramverk som kan användas vid big data-behandling. De två ramverken som testas mot varandra är Apache NiFi och Apache Storm. En metod beskrivs för att, för det första, konstruera ett dataflöde och, för det andra, konstruera en metod för att testa prestandan och skalbarheten av de ramverk som kör dataflödet. Resultaten avslöjar att Apache Storm är snabbare än NiFi, på den typen av test som gjordes. När antalet noder som var med i testerna ökades, så ökade inte alltid prestandan. Detta visar att en ökning av antalet noder, i en big data-behandlingskedja, inte alltid leder till bättre prestanda och att det ibland krävs andra åtgärder för att öka prestandan.

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Lindström, Robin. "HDV Simulink Real World Model for Testing : A Study on Model Simplicity." Thesis, KTH, Optimeringslära och systemteori, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188915.

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The purpose of this thesis was to investigate the area of model complexity and see what precautions could be made to avoid the generation of complex models. These findings included five principles stated by M. Pidd which were implemented in the development of a new Simulink real world model of a heavy duty vehicle. The developed model was integrated into a hardware-in-the-loop configuration and parameterized and validated by comparing the new model to the previous model in several advanced emergency brake test cases. Additional testing was done to prove the overall robustness and validity of the new model. With an average relative error of 2% compared to measurement data of the previous model and the additional testing considered passed, the new model was deemed valid and representative of a heavy duty vehicle. The study recommends that further simplifications are done in the hardware integration framework, which have not been targeted in this thesis, to reduce the complexity of the overall model further. All and all the new model met the deliveries and due to its less complex structure and maintained validity it was implemented at the REVT department at Scania CV AB.
Syftet med det här examensarbetet var att undersöka ämnet modell komplexitet och se vilka åtgärder som kan vidtas för att undvika skapandet av komplexa modeller. Studien inkluderar fem principer skrivna av M. Pidd vilka implementerades i skapandet av en ny Simulink omvärldsmodell av ett tungt fordon. Den utarbetade modellen integrerades i ett hardware-in-the-loop ramverk och parametriserades och validerades genom att jämföra den nya modellen mot den gamla i ett flertal testfall för den avancerade nödbromsen. Ytterligare tester genomfördes även för att bekräfta hållbarheten och giltigheten hos den nya modellen. Med ett snitt relativt fel på 2 % jämfört med mätdata från den tidigare modellen och godkänt resultat från de ytterligare testerna, ansågs den nya modellen vara en giltig och representativ avbild av ett tungt fordon. Studien rekommenderar att ytterligare förenklingar görs på hårdvaruramverket, som inte har berörts i det här arbetet, för att reducera komplexiteten hos modellen i helhet ytterligare. Överlag så levde modellen upp till alla krav och på grund av dess reducerade komplexa struktur och bibehållna giltighet, implementerades den på REVT avdelningen på Scania CV AB.

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CAETANO, Rafael Rodrigues. "O papel do supressor tumoral RBM5 em hepatocarcinoma celular induzido por HDV." Master's thesis, Instituto de Higiene e Medicina Tropical, 2018. http://hdl.handle.net/10362/38537.

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O vírus da hepatite delta (HDV) é um vírus hepatotrópico responsável pela forma mais severa e mortal de hepatite viral. O HDV co-infeta ou super-infeta hepatócitos previamente infetados pelo vírus da hepatite B (HBV), aumentando o risco de desenvolvimento de cirrose, carcinoma hepatocelular (HCC) e hepatite fulminante. A associação clínica entre estes dois vírus explica-se pelo facto do invólucro externo do HDV ser constituído pelas proteínas de superfície do HBV (HBsAgs). O HDV é assim considerado um vírus satélite do HBV. O genoma do HDV, com cerca de 1700 nucleótidos, consiste numa molécula de RNA circular de cadeia simples com polaridade negativa que codifica uma única proteína, o antigénio delta. Devido à sua simplicidade, presume-se que as etapas de transcrição e replicação do HDV estejam intimamente dependentes da maquinaria da célula infetada. Consequentemente, a análise das interações estabelecidas entre o genoma e/ou proteínas do HDV e as proteínas do hospedeiro, assume um elevado interesse dada a possibilidade de virem a ser utilizadas como potenciais novos alvos terapêuticos, que são essenciais dado que até à data não existe nenhuma terapia específica para HDV. Recentemente, o nosso laboratório utilizou o sistema de três híbrido em levedura para identificar proteínas do hospedeiro que interagem com o RNA genómico do HDV. Um dos fatores celulares identificados foi o fator de splicing SF3B155, uma proteína que faz parte do complexo U2snRNP e que é essencial para as etapas iniciais de reconhecimento de locais de splicing nos pre-mRNAs de genes humanos. Partindo da hipótese experimental que o RNA genómico do HDV funciona como um transcrito tóxico que sequestra SF3B155 e desregula o normal funcionamento do splicing alternativo, fomos avaliar o efeito da expressão de HDV no splicing de genes dependentes de SF3B155. Utilizando a linha celular Huh7 como modelo celular humano de infeção de HDV, mostramos que a expressão de HDV promove um conjunto de alterações de splicing no transcrito do gene RBM5 com consequente redução dos níveis proteicos desse fator. O RBM5 é um gene supressor tumoral que codifica um regulador transcricional implicado no controlo da expressão de genes envolvidos em progressão de ciclo celular e apoptose. Dada a redução dos níveis proteicos de RBM5 observados, fomos analisar os níveis de expressão de genes regulados por RBM5, tanto no modelo de células Huh-7 como em hepatócitos primários humanos (PHH) infetados com HDV. Em ambos os modelos utilizados, os resultados por nós obtidos mostraram alterações de expressão num conjunto de genes que incluem oncogenes com papel bem documentado no desenvolvimento e progressão de HCC, como STAT3, CDK2 e DNMT3B por exemplo. Cumulativamente, os resultados descritos neste trabalho mostram que a expressão de HDV em células humanas tem a capacidade de modular o splicing e os níveis transcricionais de diversos genes humanos, alterações essas que podem funcionar como biomarcadores de HCC induzido por HDV e vir a ser alvos favoráveis para futuras intervenções terapêuticas.
The hepatitis delta virus (HDV) is a hepatotropic virus responsible for the most severe and deadly form of viral hepatitis. HDV co-infects or super-infects hepatocytes previously infected with the hepatitis B virus (HBV), increasing the risk of developing cirrhosis, hepatocellular carcinoma and fulminant hepatitis. The clinical association between these two viruses is explained by the fact that the outer envelope of HDV consists of HBV surface proteins (HBsAgs). HDV is thus considered a satellite virus of HBV. The HDV genome is composed of approximately 1700 nucleotides and exists as a negative sense, single stranded, circular RNA molecule which encodes a single protein, the delta antigen. Due to its simplicity, it is assumed that HDV hijacks the host cell machinery to complete its transcription and replication steps. As such, the analysis of the interactions established between the HDV genome and/or proteins and host proteins is of high interest given their potential use as therapeutic targets, which are essential given that there is currently no specific therapy for HDV. Recently, our laboratory used the yeast three-hybrid system to identify host proteins that interact with the HDV genomic RNA. One of the cellular factors we identified was the splicing factor SF3B155, a protein that is part of the U2snRNP complex which is essential for the initial recognition steps of splicing sites in the pre-mRNA of human genes. Based on the experimental hypothesis that HDV genomic RNA functions as a toxic transcript that sequesters SF3B155 and deregulates the normal functioning of alternative splicing, we were able to evaluate the effect of HDV expression on the splicing of SF3B155 dependant genes. Using the Huh-7 cell line as a human cell model for HDV infection, we showed that HDV expression promotes a set of splicing changes in the RBM5 gene transcript with consequent reduction of the protein levels of this factor. RBM5 is a tumour suppressor gene that encodes a transcriptional regulator that controls the expression of genes involved in cell cycle progression and apoptosis. Given the reduction in RBM5 protein levels observed, we analysed the expression levels of RBM5 regulated genes, both in the Huh-7 cell model and in human primary hepatocytes (PHH) infected with HDV. In both models, the results obtained by us have shown expression changes in a set of genes that include well documented oncogenes involved in the development and progression of HCC, such as STAT3, CDK2 and DNMT3B for example. Cumulatively, the results described in this work show that HDV expression in human cells has the ability to modulate splicing and the transcriptional levels of several human genes, which can function as biomarkers for HDV induced HCC and become favourable targets for future therapeutic interventions.

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32

Marino, Paolo. "The surface chemistry of HDGS : The effect of modification on the adhesion of radiation curable coatings." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529447.

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Baubet, Bertrand. "Influence de la morphologie 2D de la phase active sur la sélectivité des catalyseurs sulfures en HDS des essences." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10067.

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Ce travail de thèse étudie l’influence de la morphologie des feuillets de sulfure de molybdène sur la sélectivité des catalyseurs d’hydrotraitement. Les feuillets de phase active présentent en effet deux types de bords appelés « M-edge » et « S-edge » susceptibles de conduire à des réactivités différentes. Le changement de la morphologie 2D des feuillets pourrait modifier les proportions de bords M et S exposés et ainsi les propriétés catalytiques des catalyseurs sulfures. Pour cela, des catalyseurs non promus (Mo) et promus (CoMo), supportés sur alumine ont été préparés par imprégnation à sec puis sulfurés dans des conditions variées (gaz et température). Des tests catalytiques en hydrodésulfuration (HDS) sélective des essences de FCC (sélectivité HDS/HYD) ont ensuite permis d’évaluer l’impact de la morphologie en s’appuyant sur des modèles géométriques construits à partir de calculs DFT et de caractérisations expérimentales (TEM, IR (CO), TPR, XPS). Les résultats obtenus pour les catalyseurs de type Mo semblent ainsi confirmer l’influence de la morphologie 2D sur la sélectivité HDS/HYD, le bord M paraissant être le plus sélectif pour les catalyseurs non promus. Ils mettent également en évidence l’importance de la réductibilité plus ou moins marquée des bords sur les propriétés catalytiques, notamment sur le bord M. Le changement des conditions de sulfuration semble donc affecter la morphologie des particules mais également les propriétés chimiques propres à chaque bord. En ce qui concerne les catalyseurs promus, la variation des conditions de sulfuration semble agir essentiellement au niveau de la répartition du promoteur entre les bords M et S. Cependant, les interactions avec le support paraissent constituer un frein aux effets de promotion. Dans ce contexte, les sulfurations à haute température sous H2S pur permettent d’obtenir des gains significatifs en activité et sélectivité. Ces résultats semblent dus à de faibles interactions avec le support et une décoration privilégiée du bord S qui pourrait favoriser la réaction d’HDS et limiter la réaction d’HYD. Au final, les interprétations effectuées en terme de morphologie 2D tendent à confirmer que ce paramètre peut constituer un axe de développement intéressant pour les catalyseurs d’hydrotraitement. L'optimisation des conditions de sulfuration permettraient bien de faire varier la morphologie et le taux de décoration du promoteur des catalyseurs, améliorant ainsi significativement l'activité et la sélectivité
This thesis examines the influence of the morphology of particles of molybdenum sulfide on selectivity of hydrotreating catalysts. Nanoparticles of active phase present two types of edges called “M-edge” and “S-edge” which may lead to different reactivities. The change in morphology of the 2D sheets could change the proportions of M and S edges exposed and thus the catalytic properties of sulfide catalysts. For this, non-promoted (Mo) and promoted (CoMo) catalysts, supported on alumina were prepared by dry impregnation and sulfide in various conditions (gas and temperature). Catalytic tests in selective hydrodesulfurization (HDS) of FCC gasoline (selectivity HDS /HYD) were then used to assess the impact of the morphology based on geometrical models which were constructed with DFT calculations and experimental characterizations (TEM, IR (CO), TPR, XPS). The results for Mo catalysts seem to confirm the influence of the 2D morphology selectivity HDS / HYD, M-edge appearing to be the most selective for non-promoted catalysts. They also highlight the importance of the reducibility more or less pronounced of the edges on the catalytic properties, especially on the M-edge. The different conditions of sulfidation seem to affect the morphology of the particles but also the specific chemical properties at each edge. Regarding to the promoted catalysts, the different conditions of sulfidation appear to act primarily at the distribution of the promoter between the M and S edges. However, interactions with the carrier appear to constitute an obstacle to promoting effects. In this context, sulfidations at high temperature in pure H2S lead to obtain significant gains in activity and selectivity. These results appear to be due to weak interactions with the carrier and to the presence of the promoter on the S-edge which could promote the HDS reaction and limit the HYD reaction. Finally, the interpretations made in terms of 2D morphology tend to confirm that this parameter can be an interesting line of development for hydrotreating catalysts. Optimization of the sulfidation conditions could effectively allow to vary the morphology and the rate of decoration of promoted catalysts which significantly improve the activity and selectivity

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Lorente, Leal Alberto. "KTHFS Orchestration : PaaS orchestration for Hadoop." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128935.

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Platform as a Service (PaaS) has produced a huge impact on how we can offer easy and scalable software that adapts to the needs of the users. This has allowed the possibility of systems being capable to easily configure themselves upon the demand of the customers. Based on these features, a large interest has emerged to try and offer virtualized Hadoop solutions based on Infrastructure as a Service (IaaS) architectures in order to easily deploy completely functional Hadoop clusters in platforms like Amazon EC2 or OpenStack. Throughout the thesis work, it was studied the possibility of enhancing the capabilities of KTHFS, a modified Hadoop platform in development; to allow automatic configuration of a whole functional cluster on IaaS platforms. In order to achieve this, we will study different proposals of similar PaaS platforms from companies like VMWare or Amazon EC2 and analyze existing node orchestration techniques to configure nodes in cloud providers like Amazon or Openstack and later on automatize this process. This will be the starting point for this work, which will lead to the development of our own orchestration language for KTHFS and two artifacts (i) a simple Web Portal to launch the KTHFS Dashboard in the supported IaaS platforms, (ii) an integrated component in the Dashboard in charge of analyzing a cluster definition file, and initializing the configuration and deployment of a cluster using Chef. Lastly, we discover new issues related to scalability and performance when integrating the new components to the Dashboard. This will force us to analyze solutions in order to optimize the performance of our deployment architecture. This will allow us to reduce the deployment time by introducing a few modifications in the architecture. Finally, we will conclude with some few words about the on-going and future work.

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Blaho, Matúš. "Aplikace pro Big Data." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2018. http://www.nusl.cz/ntk/nusl-385977.

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This work deals with the description and analysis of the Big Data concept and its processing and use in the process of decision support. Suggested processing is based on the MapReduce concept designed for Big Data processing. The theoretical part of this work is largely about the Hadoop system that implements this concept. Its understanding is a key feature for properly designing applications that run within it. The work also contains design for specific Big Data processing applications. In the implementation part of the thesis is a description of Hadoop system management, description of implementation of MapReduce applications and description of their testing over data sets.

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Bhat, Adithya. "RDMA-based Plugin Design and Profiler for Apache and Enterprise Hadoop Distributed File system." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440188090.

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Khandrika, Ananth Viswa Sai Kalyan. "ASHWHIN- Array Storage system on HadoopFS With HDF5 Interface." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524063297966335.

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Hamad, Shaimaa Kamal. "Developmental gene expression of host defense peptides in immune organs and the small intestine of turkey poults (Meleagris gallopavo)." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73056.

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Host defense peptides (HDPs) are a large group of small positively charged peptides that play an important role in innate immunity. Their role is more critical at early ages when other components of the immune system have not fully developed. There are three classes of avian HDPs: avian beta defensins (AvBDs), cathelicidins (Cath) and liver-expressed antimicrobial peptide 2 (LEAP-2). The objective was to compare expression of HDPs in male turkey poults at day of hatch (D0), D7, D14, D21 and D28 from the thymus, spleen, bursa, duodenum, jejunum and ileum. The expression of AvBD1, AvBD2, AvBD8, AvBD9, AvBD10, AvBD13, Cath2, Cath3 and LEAP-2 was measured using qPCR (n=6 birds/tissue/age). Data were analyzed by one-way ANOVA and Tukey's test, and significance considered at P ≤ 0.05. AvBDs and Caths exhibited greater expression in immune organs than intestinal tissues, with the greatest expression of AvBDs observed in the spleen. The intestinal tissues showed very low expression of AvBDs except for AvBD10 at D0. Similar to AvBDs, Caths expression in the immune organs was greater than the intestinal tissues with the spleen having the greatest expression among immune organs. Conversely, LEAP-2 showed greater expression in the intestinal tissues than in the immune tissues, which showed very low LEAP-2 expression unlike other HDPs. Understanding the differential expression of HDPs could reveal the innate immune status of poults, and may subsequently allow improvement of their health through appropriate mitigation strategies.
Master of Science

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OKUMA, Shigeru, Tatsuya SUZUKI, YoungWoo KIM, and Tatsuya KATO. "Model Predictive Control of Traffic Flow Based on Hybrid System Modeling." Institute of Electronics, Information and Communication Engineers, 2005. http://hdl.handle.net/2237/14988.

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Kellerman, Daniel. "Application of Internal Competition Kinetics to Probe the Catalytic Strategies of RNA 2’-O-transphosphorylation." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1449150064.

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Shirvani-Dastgerdi, Elham [Verfasser], Frank [Akademischer Betreuer] Tacke, and Jürgen [Akademischer Betreuer] Bernhagen. "Hepatitis B virus (HBV) and delta virus (HDV) interactions : effects of HDV replication on drug resistance, immune escape and HBeAg-negative mutants of HBV / Elham Shirvani-Dastgerdi ; Frank Tacke, Jürgen Bernhagen." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1127051369/34.

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Mourinho, Fabricio Andrade. "Proteção de linhas de transmissão de sistemas VSC-HVDC utilizando limitadores de corrente de falta." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-09052016-134445/.

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Tecnologias HVDC que utilizam conversores do tipo fonte de tensão, o VSC-HVDC, ainda não são completamente difundidas e aplicadas no Brasil, em contraste com outros países que começaram a estudar e empregar este tipo de transmissão. Comparado com o HVDC tradicional, o VSC-HVDC é uma tecnologia de transmissão mais eficiente e pode superar deficiências encontradas na transmissão em corrente contínua convencional. O VSC-HVDC pode ser utilizado de maneira mais eficiente nas novas redes de energia, para alimentar ilhas, integração de geração eólica, renovação das linhas em centros urbanos, aplicações multiterminais e conexão com sistemas fracos. Por se tratar de uma tecnologia recente, o VSC-HVDC ainda não é amplamente adotado e uma das principais limitações da utilização destes sistemas é a sua fragilidade diante faltas na linha de corrente contínua. Neste contexto, limitadores de corrente de falta (LCF) podem ser utilizados para minimizar o impacto das faltas. A ação dos limitadores é benéfica ao sistema durante condições de falta, contudo, ainda assim é necessária a atuação do sistema de proteção para extinguir a condição faltosa. Portanto, este trabalho visa propor e avaliar um novo esquema de proteção que opere de maneira seletiva e confiável para sistemas VSC-HVDC na presença de LCF baseados em materiais supercondutores ou LCF indutivos. Para tanto, foram implementadas quatro funções de proteção tradicionais das linhas em CC, a saber: direcional de corrente, diferencial, sobrecorrente com restrição de tensão e ondas viajantes, e ainda, foi proposta uma nova função de proteção, a de condutância, a qual apresentou o menor tempo de identificação de falta, considerando as faltas mais severas. Adicionalmente, foi avaliado o comportamento destas funções quando o sistema apresenta os LCF em série com a linha. Foi demonstrado que é possível extrair os benefícios dos LCF sem deteriorar a qualidade dos resultados das funções de proteção, o que aumenta a segurança e confiabilidade dos sistemas VSC-HVDC, uma vez que os impactos das faltas são minimizados e as mesmas são identificadas em um curto intervalo de tempo.
HVDC technology based on voltage source converters, VSC-HVDC, are not yet fully disseminated and applied in Brazil, in contrast to other countries that have begun to study and widely employ this type of transmission technology. When compared with traditional HVDC systems, VSC-HVDC systems are more efficient and can overcome the challenges encountered in the conventional direct current transmission. The VSC-HVDC can be used more efficiently in the new energy networks to feed islands, integration of wind generation, renewal of lines in urban centers, multiterminal applications and connection with weak systems. Because it is a recent technology, VSC-HVDC is not yet widely adopted and a major limitation of using these systems is their weakness against faults in the DC line. In this context, fault current limiters (FCL) can be used to minimize the impact of faults. The action of the limiters is beneficial to the system during fault conditions, however, the use of protection schemes to detect the fault and extinguish the faulty condition is still required. Therefore, this work aims to propose and evaluate a new protection scheme operating in selective and reliable way for VSC-HVDC systems in the presence of FCL based in superconductor materials or inductive FCL. To reach such a goal, in this work it has been implemented four traditional DC lines protection functions, namely: directional current, differential, overcurrent with voltage restraint and traveling waves, and also proposed a new protection function, which is based on the conductance. This last protection function has presented the lowest detection time, when considering the most severe faults. In addition, it was evaluated the behavior of these functions when the system presents the FCL in series with the DC line. It has been shown that it is possible to extract the benefits of FCL without deteriorating the quality of the results of the protection functions, which increases the safety and reliability of the VSC-HVDC systems, since the impact of faults is minimized and they are identified in a short time.

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Kulkarni, Kunal Vikas. "Performance Characterization and Improvements of SQL-On-Hadoop Systems." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469147027.

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Larson, Christine M. "Construction and Validation of a Self-Report Measure of Trichotillomania Distress: The Hairpulling Distress and Impairment Scale (HDIS)." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1184697559.

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Isaksson, Jonas. "Förbättringsåtgärder för en ökad talloljeproduktion vid Smurfit Kappa Piteå." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-61823.

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Sodapannan hos Smurfit Kappa Piteå är en av flaskhalsarna i produktionsflödet. Detta har till följd att tjockluten ackumulerar medan resterande lutar minskar, på grund av detta måste övriga enheter tidvis minska produktionen. Sodapannan har dessutom gett en varierad ångproduktion per ts (torrsubstans) lut vilket tros vara relaterat till lutens såpinnehåll, tidigare analyser påvisat stora variationer i avsåpning. Eftersom såpa har högre energivärde än svartlut ligger detta som grund till kopplingen mellan variationen i ångproduktion per ts lut och avsåpningen. Avskild såpa vidareförädlas till tallolja i hartskokeriet, Smurfit Kappa Piteå använder en HDS (hydrodynamisk separator) för att avskilja tallolja från spjälkvätska. Tallolja används bland annat för framställning av biodiesel och de senaste årens intresse för biobränslen har även bidragit med större fokus på talloljetillverkningen vid pappersbruken. Smurfit Kappa Piteå har på senare tid gjort två större förändringar som har en direkt påverkan på talloljeproduktionen. Avsåpningsparken har byggts ut och flödet av spjälkvätska har lagts om till efter avsåpning istället för före avsåpning. Företaget är därför intresserade av en djupare analys för att undersöka hur förändringarna påverkat talloljeproduktionen och vad som kan göras för att ytterligare förbättra den. I detta projekt undersöks förluster av såpa och tallolja till sodapannan, hur förlusterna påverkar ångproduktionen per ts lut samt möjliga förbättringsåtgärder för en ökad talloljeproduktion. För att utreda förlusterna genomfördes en kartering vid tio olika tillfällen där talloljeinnehåll i svartlut samt såpans talloljeinnehåll fastställdes. Från detta erhölls följande resultat; avsåpningens verkningsgrad var cirka 94 % i blandlutssteget och 0 % i mellanlutssteget. Medelutbytet av tallolja i hartskokeriet var 70 %. Resultatet från karteringen analyserades med SIMCA tillsammans med tillgängliga variabler som påverkar avsåpningen, ingen specifik variabel visades påverka avsåpningen i betydande grad. Via en sammanställning av tallolje- och såpförlusterna visades en förbättringspotential för ökad talloljeproduktion på 42 % över HDS:en och 4 % över blandlutssteget vid hypotetiska utbyten på 100 % för vardera enhet. Ur förlusterna beräknades även den extra belastning som erläggs sodapannan och hur ångproduktionen per ts lut varierade med avseende på detta. Variationen i ångproduktion per ts lut gick inte att korrelera till förlorad såpa och tallolja. Vid drift av HDS:en, bidrog dess talloljeförluster med 1,1 % ökning av medelenergi på brännluten samtidigt som förlusten av såpa vid avsåpning bidrog med en medelenergiökning på 0,3 %. Utöver detta undersöktes även talloljeproduktionen med avseende på massaproduktionen för perioden 2010-2016. Från detta kunde en tydlig årstidsvariation urskiljas. Totalutbytet av tallolja från massa hade stigit samtidigt som kvoten löv/barr minskat. De senaste månaderna påvisade ett minskat totalutbyte av tallolja från massan vilket kopplades till omläggning av spjälkvätska till efter avsåpning från att tidigare återinförts före avsåpning.

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Szakal, Andrea L. Bevilacqua Philip C. "The hepatitis delta virus (HDV) ribozyme as a model for RNA catalysis and folding." [University Park, Pa.] : Pennsylvania State University, 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2700/index.html.

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47

Okudan, M. Demet Akçil Ata Utku. "Kobalt ve molibden içeren kullanılmış hidrodesülfürizasyon (HDS) katalizör atıklarına asidik ve alkali liç uygulaması /." Isparta : SDÜ Fen Bilimleri Enstitüsü, 2009. http://tez.sdu.edu.tr/Tezler/TF01245.pdf.

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TSISHKOVSKA, Maryna. "Inibidores de prenilação como uma nova estratégia terapêutica de tratamento da infeção por HDV." Master's thesis, Instituto de Higiene e Medicina Tropical, 2018. http://hdl.handle.net/10362/38538.

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O vírus da hepatite delta (HDV) é o agente responsável pela forma mais severa e mortal de hepatite viral. O HDV co-infeta ou super-infeta hepatócitos previamente infetados pelo vírus da hepatite B (HBV), aumentando o risco de desenvolvimento de cirrose, carcinoma hepatocelular (CHC) e hepatite fulminante. A associação clínica entre estes dois vírus é justificada pelo facto do invólucro externo do HDV ser constituído pelas proteínas de superfície do HBV (HBsAgs). O genoma do HDV é constituído por uma única molécula de RNA circular de cadeia simples, que codifica uma única proteína, o antigénio delta (HDAg). A ocorrência de um mecanismo de editing do RNA, resulta na expressão de duas formas do HDAg, a pequena (S-HDAg) e a grande (L-HDAg). Estas duas proteínas virais desempenham funções várias no ciclo do HDV, enquanto que o S-HDAg estimula a replicação do RNA viral, o L-HDAg é responsável pela interação com os HBsAgs para formar partículas virais. Tendo em conta a inexistência de uma terapia disponível para a hepatite delta, é essencial o desenvolvimento de novas terapêuticas mais eficazes e seguras. A necessidade de encontrar novas opções terapêuticas levou ao desenvolvimento de fármacos dirigidos a moléculas específicas relevantes no ciclo do vírus delta. Este é o caso do mecanismo de prenilação do L-HDAg, catalisado por enzimas celulares do grupo das farnesil-transferases. Desta forma, inibidores desta enzima celular poderão constituir uma abordagem terapêutica promissora da infeção provocada por HDV. A necessidade de encontrar novas opções terapêuticas, levou-nos a desenvolver um estudo em que se avaliou o potencial terapêutico dos inibidores de farnesil-transferases tais como FTI-277, compostos A e B nas células da linha celular Huh7D12, avaliando o impacto em termos de viabilidade celular e correlacionando a capacidade dos fármacos de intervir nos níveis de expressão do genoma viral do HDV. Avaliamos ainda a ação destes inibidores sobre a expressão de oncogenes associados ao desenvolvimento de CHC. Para tal, as células Huh7D12 foram incubadas com concentrações crescentes de FTI-277, composto A e B durante 48h. A viabilidade celular foi testada utilizando o CellTiter-Blue® Cell Viability Assay Kit e os níveis de expressão do RNA genómico do HDV e de oncogenes (STAT3, NF-kB, PIM1, BMP5, CDK2) através da reação de PCR utilizando um par de primers específicos. A análise dos efeitos em termos de viabilidade celular demonstrou que os compostos A e B são menos tóxicos para as células da linha celular Huh7D12 do que o inibidor comercial FTI-277 face às mesmas concentrações de fármaco. Verificou-se também que os compostos A e B, tal como o fármaco comercial FTI-277, apresentam o mesmo efeito sobre a expressão do RNA genómico do HDV e os oncogenes STAT3 e NF-kB, porém com menor interferência na viabilidade celular, o que pode contribuir para melhorar a eficácia terapêutica com diminuição da toxicidade e dos efeitos secundários. Os resultados obtidos neste trabalho mostraram que os fármacos dirigidos a farnesil-transferases celulares podem constituir uma nova abordagem terapêutica promissora no tratamento da hepatite delta crónica e como supressores de processos cancerígenos.
Hepatitis delta virus (HDV) is the causative agent of one of the most severe forms of viral hepatitis. HDV occurs either coinfection or as superinfection in patients with pre-existing hepatitis B virus (HBV) infection and increases the risk and rapid progression to cirrhosis, hepatocellular carcinoma (CHC) and fulminant liver failure. The clinical association between these two viruses is justified by the fact that the envelope of HDV is composed by hepatitis B surface antigens (HBsAgs). The HDV genome is a circular single-stranded RNA molecule, which encodes a single protein called the delta antigen (HDAg). The occurrence of an RNA editing mechanism results in expression of the two delta antigen isoforms, the small (S-HDAg) and the large (L-HDAg). Both forms of these viral proteins are importante for distinct steps within the HDV life cycle, whereas the S-HDAg supports HDV replication, the L-HDAg interact with HBsAg to assemble new virions. At this time there is no available therapy for hepatitis delta, wich make necessary the development of new, more effective and safe therapies. The need to find new therapeutic options led to the development of drugs targeting specific molecules in the delta virus cycle. This is the case of the prenylation mechanism of L-HDAg, catalyzed by cellular enzymes of the farnesyltransferase group. In this way, inhibitors of this cellular enzyme may constitute a promising therapeutic approach to HDV-induced infection. The need to find safe and efficient therapeutic options, led us to develop a study to evaluate the therapeutic potencial of farnesyltransferase inhibitors, such as the FTI-277, compounds A and B in a Huh7D12 cell line. We evaluated the impact in term of cell viability and correlated the ability of these drugs to intervene in the expression of the HDV viral genome. We also evaluated the action of these inhibitors on the expression of oncogenes associated with the development of CHC. For this purpose, Huh7D12 cells were incubated for 48 hours with rising concentrations of FTI-277, compounds A and B. Cellular viability was assessed by use the CellTiter-Blue® Cell Viability Assay Kit and the expression levels of HDV genomic RNA and oncogenes (STAT3, NF-kB, PIM1, BMP5, CDK2) by the PCR reaction using the specific primers. Analysis of effects in terms of cell viability has shown that compounds A and B are less toxic to cells on Huh7D12 cell line than the commercial inhibitor FTI-277 at the same drug concentrations. Compounds A and B, like the commercial drug FTI-277, have also been shown to have the same effect on the HDV genomic RNA and on the oncogenes STAT3 and NF-kB, but with less interference in cell viability, which may contribute to improving therapeutic efficacy with decreased toxicity and side effects. The results obtained in this work, showed that the farnesyltransferase inhibitors used in this study may constitute a promising new therapeutic approach in the treatment of chronic delta hepatitis and as suppressors of carcinogenic processes.

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49

Antunes, Florence Pereira Novais. "Determinação de propriedades e estruturas de catalisadores de sulfeto de molibdênio suportados em MgO por cálculos ab initio." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/317.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Associada à redução das emissões veiculares, o principal processo de interesse no hidrotratamento é a hidrodessulfurização, HDS, na qual o átomo de enxofre presente nas moléculas organosulfuradas é adsorvido no catalisador e reage com hidrogênio, formando sulfeto de hidrogênio (H2S) e os hidrocarbonetos livres de heteroátomos. As reações de HDS são exotérmicas e irreversíveis, sendo que seu mecanismo envolve reações de hidrogenólise – quebra da ligação CS – e de hidrogenação – saturação das duplas ligações. Existem divergências na literatura sobre o mecanismo dessas reações. O interesse pela área de materiais relacionados às reações deste tipo e à catálise heterogênea está em constante expansão devido à possibilidade de produzir diversos tipos de materiais de grande aplicabilidade e custos menos onerosos. Os estudos sobre HDS buscam o desenvolvimento de catalisadores com maior capacidade para promover uma remoção mais efetiva do enxofre, além de esclarecimentos referentes ao seu mecanismo. Os catalisadores mais comumente usados são compostos que possuem estruturas de MoS2 como fase ativa. Apesar de possuir atividade catalítica na forma mássica, o MoS2 geralmente é suportado em uma superfície com extensa área como suporte, geralmente óxidos, sendo a γalumina a mais utilizada. Existem diversos estudos recentes reportando uso de outros tipos de óxidos, como TiO2, sílica, zeólitas, ZrO2, MgO e óxidos mistos. No presente trabalho, é feita a proposta de dois tipos de estruturas de catalisadores de sulfeto de molibdênio suportados em MgO, através de cálculos ab initio. É de aceitação geral, hoje em dia, que a atividade dos catalisadores de HDS está fundamentalmente ligada à existência de vacâncias aniônicas de enxofre, situadas, predominantemente, nas bordas dos cristalitos da fase ativa, já que o enxofre dos planos basais está muito fortemente ligado para permitir a formação destas vacâncias. Levandose em conta que a formação de vacâncias é uma etapa crucial para HDS, procuramos obter informações estruturais mais precisas que auxiliem no entendimento dessa etapa da reação. Para isso mostramos o estudo da formação de sítios coordenativamente insaturados na borda do sulfeto de molibdênio suportado em MgO. Além disso, discutimos a interação do sulfeto com o suporte, variando o número de camadas de sulfeto e a presença de átomo promotor de cobalto na borda. Com isso, procuramos fornecer informações estruturais de modelos teóricos de MoS2 suportado em MgO utilizando DFT a fim de contribuir com estudos nesse contexto. Para isso, foi calculada a energia de formação de vacâncias, diferença da densidade de cargas eletrônicas, pDOS e análise das cargas de Bader. Concluímos que tanto o suporte quanto o átomo promotor influenciam na formação de vacâncias na borda do sulfeto de molibdênio suportado em MgO. A influência dessas variáveis está em dependência com o tamanho da lamela, proporções de átomos de enxofre de borda e tipo de interação do sulfeto com o suporte. Em geral podemos afirmar que os dois agem de modo a diminuir a energia de formação de vacâncias, contribuindo para a melhora dessa etapa.
With respect to the reduction of pollutant emission of vehicles, the main process of hydrotreatment is the hydrodesulfurization, HDS, in which the sulfur atom of the organosulfur molecules is adsorved on the catalyst and reacts with hydrogen forming hydrogen sulfide (H2S) and heteroatomfree hydrocarbons. The HDS reactions are exothermic and irreversible and their mechanisms involve hydrogenolysis reactions – the break of CS bond – and the hydrogenation – saturation of double bonds. There are many divergences in the literature about the mechanism of these reactions. The interest about these types of reactions and the heterogenous catalysis in the material field is in constant expansion due to the possibility of producing several types of materials with great applicabilities and inferior costs. The studies about HDS seek the development of catalysts with a higher capacity to promote a more effective removal of sulfur besides the elucidation of their mechanisms. The catalysts more commonly used are compounds which possess MoS2 structures as the active phase. Even though it has catalytic activity in the bulk structure, the MoS2 is generally supported on a surface with an extended area, usually oxides such as alumina, which is the most utilized. There are many recent studies γ reporting the use of other types of oxides such as TiO2, silica, zeolites, ZrO2, MgO and mixed oxides. In this present work, a proposition of two types of catalyst structures of molybdenum sulfides supported on MgO is done by means of ab initio calculations. It is commonly accepted nowadays that the activity of HDS catalysts is greatly related to the existence of anionic vacancies of sulfur located majorly on the edges of the active phase, since the sulfurs of the basal planes are strongly bonded to permit the formation of these vacancies. Taking into account that the vacancy formation is a crucial step for HDS, we sought to obtain more precise structural information to assist the understanding of this reaction step. Thereby, we presented the study of the formation of the coordenative unsaturated sites on the edge of the molybdenum sulfide supported on MgO. Moreover, we discussed about the interaction between the sulfide and the support by varying the amount of the sulfide layers and the presence of the cobalt atom on the edge. Thereby, we sought to provide structural information on the theoretical models of MoS2 supported on MgO using DFT in order to contribute with studies in this context. In order to do that, we calculated the energy of the vacancy formation, the difference of the charge densities, pDOS and Bader charge analysis. We concluded that the support and the promoting atoms influence the formation of the vacancies on the edge of the molybdenum supported on MgO. The influence of these variables depends on the size of the layer, the proportions of the sulfur atoms on the edge and the type of the interaction of the sulfide on the support. In short, we can confirm that both act to decrease the energy of the vacancy formation, thus contributing to the improvement of this step.

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50

Zanotello, Tatiane Cristina. "Adição de fósforo (P) em catalisadores NiMo, suportados em γ-Al2O3, Al2O3/TiO2 e TiO2 - efeito na hidrodessulfurização do tiofeno." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/4108.

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Universidade Federal de Sao Carlos
Mo, NiMo or NiMoP HDS catalysts were supported on Al2O3, Al2O3-TiO2 or TiO2. These supports were synthesized via sol-gel and in the case o TiO2 it was used a commercial sample. The active phases were introduced by impregnation. Supports and catalysts in the oxide form were characterized by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectroscopy (DRSUV-Vis), thermogravimetric analyses (TG), temperature-programmed reduction with H2 (TPR-H2), N2 adsorption/desorption, energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF), temperature-programmed desorption of NH3 (TPD-NH3), high resolution transmission electron microscopy (HRTEM) and evaluated at 300°C in the HDS of thiophene, used as a model molecule. Alumina presented a high specific surface area and meso/macroprous characteristics, allowing a high dispersion of the active phases, as was evidenced by XRD and DRSUV-VIS data. A HRTEM image of a NiMo/Al2O3 catalyst showed the presence of crystalline MoS2 whose activity was substantially promoted by the presence of Ni. The NiMo catalysts were active in the HDS of thiophene, however, the activity was enhanced significantly by the incorporation of P. This result corroborates the positive influence of P in the preparation of HDS catalysts. It was suggested that P must participate as promoter in the formation of the NiMoS phase during the sulfidation process of the Ni and Mo oxides. The supported NiMoP catalysts prepared in this work were more active than a commercial NiMoP/ Al2O3 catalyst, with this result validating the preparation procedures used here. The titania addition in the alumina framework led to NiMo catalysts possessing lower activity. That behavior was attributed to the formation of Ni and Mo sulfides without interaction diminishing the generation NiMoS phase, which is highly active in the HDS of sulfured organic compounds.
Catalisadores para hidrodessulfurização (HDS) contendo Mo, NiMo ou NiMo e o aditivo fósforo (P), foram suportados sobre Al2O3, Al2O3-TiO2 ou TiO2. A alumina e a alumina-titânia foram sintetizadas via sol-gel e, no caso da titânia pura, utilizada uma amostra comercial. A introdução dos sais precursores da fase ativa foi realizada via impregnação. Suportes e catalisadores na forma de óxidos foram caracterizados através de difração de raios X (DRX), espectroscopia por refletância difusa no ultravioleta visível (DRSUV-VIS), termogravimetria (TG), redução com hidrogênio à temperatura programada (RTP-H2), adsorção/dessorção de N2, espectroscopia de energia dispersiva de raios X (EDX), fluorescência de raios X (FRX), dessorção de amônia a temperatura programada (TPD-NH3), microscopia eletrônica de transmissão de alta resolução (HRTEM) e avaliados a 300⁰C na HDS do tiofeno. A alumina apresentou uma alta área superficial específica e características meso/macroporosa, possibilitando alta dispersão das fases ativas, conforme evidenciado por DRX e dados de DRSUV-VIS. A imagem de HRTEM do catalisador NiMo/Al2O3 mostrou a presença de MoS2 cuja atividade foi promovida substancialmente pela presença de Ni. Os catalisadores NiMo sobre os suportes utilizados foram ativos no HDS do tiofeno, entretanto, essa atividade foi melhorada pela incorporação de P. Esse resultado ratifica a influência positiva da utilização desse aditivo na preparação de catalisadores de HDS. O fósforo deve atuar como um promotor na formação de espécies NiMoS durante o processo de sulfetação dos óxidos de Mo e Ni. Os catalisadores NiMoP preparados neste trabalho apresentaram atividade específica superior à de um catalisador NiMoP/Al2O3 comercial, o que valida os procedimentos de preparação utilizados no trabalho. A adição de titânia na alumina durante a síntese sol-gel conduziu a catalisadores com menor atividade. Esse resultado foi atribuído à formação de sulfetos de Ni e Mo não interativos, com a consequente diminuição da formação da fase NiMoS de alta atividade no HDS de compostos organo-sulfurados.

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