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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Untersuchung von Tetrachloroaluminatschmelzen als potentielle Wärmetransportflüssigkeiten in Solarkraftwerken

Asztalos, Annifrid 09 May 2018 (has links)
Um die Wirtschaftlichkeit von Solarkraftwerken zu verbessern, sollte geprüft werden, inwieweit eine geschmolzene Mischung aus Natriumchlorid und Aluminiumchlorid als Wärmetransportflüssigkeit in Frage kommt. Aufgrund der Hydrolyseempfindlichkeit solcher Schmelzen kommt es durch Einwirkung von Wasser zur Bildung von Chlorwasserstoff sowie Aluminiumoxidchloriden, die in einem geschlossenen System zu einem Druckanstieg bzw. Ausfällungen führen können. Der Gesamtdruck über schwach basischen NaCl-AlCl3-Schmelzen wird durch eine hohe HCl-Löslichkeit herabgesetzt, sodass aus der Bilanz heraus ein Hydrolysegrad von ca. 50 % angenommen werden kann. Für die wassermengenabhängige Verfolgung des Druckes diente eine statische Methode mit einem Drucksensor. Der Oxidgehalt wurde voltammetrisch durch Titration mit TaCl5 und die HCl-Löslichkeit durch eine Elutionsmethode ermittelt. Für Informationen zum Lösungszustand der Hydrolyseprodukte wurden 1H- und 27Al-NMR-Spektren von hydrolysierten Schmelzen aufgenommen.
32

The Strucplot Framework: Visualizing Multi-way Contingency Tables with vcd

Hornik, Kurt, Zeileis, Achim, Meyer, David 10 1900 (has links) (PDF)
This paper describes the "strucplot" framework for the visualization of multi-way contingency tables. Strucplot displays include hierarchical conditional plots such as mosaic, association, and sieve plots, and can be combined into more complex, specialized plots for visualizing conditional independence, GLMs, and the results of independence tests. The framework's modular design allows flexible customization of the plots' graphical appearance, including shading, labeling, spacing, and legend, by means of "graphical appearance control" functions. The framework is provided by the R package vcd.
33

The effects of crude glycerol, dried distillers grains with solubles, Ractopamine HCl, NutriDense corn, and feeder adjustment on growing and finishing pig performance

Duttlinger, Alan William January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Joel M. DeRouchey / A total of 6,858 pigs were used in 6 experiments to evaluate the effects of crude glycerol, dried distillers grains with solubles (DDGS), Ractopamine HCl (RAC), NutriDense corn, and feeder adjustment on growing and finishing pig performance. In Exp. 1, pigs were fed diets with 0, 2.5, or 5% crude glycerol with 0 or 20% DDGS. Adding DDGS increased ADFI and decreased G:F with no differences for pigs fed glycerol. Neither glycerol nor DDGS affected any carcass characteristics. Pigs fed DDGS had increased iodine value in carcass fat. In Exp. 2, pigs were fed diets with 0 or 5% glycerol with 0 or 7.5 ppm RAC. Feeding RAC increased ADG and G:F and decreased ADFI while glycerol tended to improve G:F. Ractopamine HCl improved carcass traits. Loin chop drip loss worsened when glycerol and RAC were added separately, however, drip loss decreased when the combination of both were fed. Glycerol did not affect loin characteristics. Neither RAC nor glycerol influenced iodine value of carcass fat. Exp. 3 and 4 were conducted to determine the 4th limiting amino acid in diets containing NutriDense corn. In Exp. 3, pigs fed the positive control and the diet with added Ile, Trp, and Val (in combination) had greater ADG. Pigs fed added Ile or Trp had greater ADG than pigs fed the negative control indicates these amino acids were co-4th limiting for 37 to 59 kg pigs. In Exp. 4, pigs fed the positive control, added Trp, or the combination of added Ile, Trp and Val had greater ADG then pigs fed the negative control or pigs fed either Ile or Val indicates these amino acids were co-4th limiting for 77 to 100 kg pigs. Exp. 5 and 6 evaluated feeder adjustment on growth performance of finishing pigs. In Exp. 5, reducing feeder opening decreased ADFI. In Exp. 6, pigs were fed at three feeder opening and either a corn-soybean meal or byproduct-based diet. Diet type did not affect pig performance. Widening feeder openings increased ADG and ADFI. Feeder setting tended to influence G:F with the best G:F at the intermediate opening.
34

Elucidating the corrosion performance of type 316L stainless steel product storage cans

Krawczyk, Benjamin January 2018 (has links)
Re-processed oxide fuel product from the Thermal Oxide Reprocessing Plant (THORP) is stored in Type 316L stainless steel, using a design of several nested cans, with the outer can providing the safety case containment barrier. The research reported in this PhD thesis aims to support the safety case related to these storage cans, by identifying and characterising susceptible microstructure sites and associated material surface conditions. The overarching goal of this project is to understand the propensity of THORP storage cans towards localised corrosion and Environment Assisted Cracking (EAC) in HCl and chloride-bearing atmospheric environments. The investigation focused on two possible corrosion cases: (1) understanding the effect of surface finishing on material performance in chloride-containing atmospheric environments, and (2) characterising the effects of the HCl aqueous solutions inside the can, with potential formation of HCl vapour. Microstructure investigations were carried out on surface-treated type 316L coupon specimens. The application of aqua blasting resulted in a deformed near-surface microstructure, containing compressive residual stresses to a depth of 100-120 micrometres. Subsequent laser engraving produced a recrystallized surface layer with tensile residual stresses reaching to a depth of 200 micrometres. Changes of surface roughness topography were accompanied by the development of a thick oxide/hydroxide film after laser engraving. Atmospheric exposure revealed similar corrosion attack for all samples, with laser engraving exhibiting the lowest number of corrosion sites, but with the largest average depth of attack. In addition, laser engraving led to atmospheric-induced stress corrosion cracking (AISCC) within two weeks of exposure to 386 ug/cm2 MgCl2-laden droplet deposits, with crack growth rates similar to ground U-bend samples. Strategies to reduce the likelihood of AISCC of laser-engraved components are discussed. The influence of HCl concentration and exposure temperature on the corrosion type and rate of annealed and cold rolled type 316L stainless steel has also been investigated. Cold rolling of up to 20 % reduction was introduced, with potentio-dynamic polarization measurements conducted in 0.01 - 3 M HCl aqueous solution. Results are compared to microstructures immersed under open circuit conditions, and to HCl-laden droplet deposits at temperatures up to 80C. Corrosion type diagrams are introduced to describe the transition between uniform corrosion, mixed-mode uniform with pitting corrosion, and pitting corrosion only, as a function of temperature, HCl concentration, and cold deformation. SCC tests of type 316L stainless steel have been carried out at 110C, by exposing U-Bend samples to HCl-laden droplets and HCl vapour. The humidity of the environment was controlled using defined volume fractions of H2O in a sealed environmental chamber. HCl-laden droplets with chloride deposition densities exceeding 1.5 ug/cm2 led to SCC after 90 minutes of exposure, whereas no corrosion attack was observed for samples with exposure to 0.15 ug/cm2 HCl. Increasing HCl concentrations resulted in fewer, but longer cracks, reaching up-to several hundreds of micrometres in length. HCl vapour exposure was carried out by adding various volumes of HCl solution in a beaker to the sealed test chambers. These HCl vapour tests confirmed a change of corrosion type with HCl concentration, from pitting corrosion with SCC, to the occurrence of uniform corrosion.
35

Influence de la méthode de fabrication de la glace et de son histoire thermique sur ses propriétés de surface. Implications atmosphériques

Chaix, Laurent 03 July 1997 (has links) (PDF)
L'influence de la méthode de préparation de la glace et de son histoire thermique sur la structure de sa surface a été mesurée a 77,15k en utilisant l'adsorption du méthane à 77,15 et 87,1k. Les isothermes d'adsorption du méthane ont été obtenues pour des recouvrements de surface compris entre 0,1 et plusieurs monocouches et entre 10-6 et 10-2 monocouche. Nous avons ainsi pu constater que la méthode de préparation et l'histoire thermique de l'échantillon de glace affectaient ses propriétés d'adsorption à faibles recouvrements ; par contre aucune influence n'a pu être décelée pour des recouvrements de surface superieurs à 0,1 monocouche. Ces différences ont ete attribuées à la présence de faces cristallographiques pouvant adsorber plus fortement le méthane, principalement des faces cristallographiques à indices de miller-bravais eleves. De ces observations nous avons conclu que la structure de la surface de la glace et ses propriétés d'adsorption dépendaient fortement de son mode de formation et de son histoire thermique. Nous avons également entrepris une étude expérimentale de l'adsorption de HCL sur la glace à 195k dans le but de contribuer à la compréhension du mécanisme chimique implique dans la destruction de l'ozone stratosphérique polaire.
36

Removal of Filter Cake Generated by Manganese Tetraoxide Water-based Drilling Fluids

Al Mojil, Abdullah Mohammed A. 2010 August 1900 (has links)
Three effective solutions to dissolve the filter cake created by water-based drilling fluids weighted with Mn3O4 particles were developed. Hydrochloric acid at concentration lower than 5 wt% can dissolve most of Mn3O4-based filter cake. Dissolving the filter cake in two-stage treatment of enzyme and organic acid was effective and eliminated the associated drawbacks of using HCl. Finally, combining low and safe concentration of HCl with an organic acid in one-stage treatment was very effective. Hydrochloric acid (10-wt%) dissolved 78 wt% of Mn3O4-based filter cake at 250°F after 28 hours soaking time. However, Chlorine gas was detected during the reaction of 5 to 15-wt% HCl with Mn3O4 particles. At 190°F, 1- and 4-wt% HCl dissolved most Mn3O4 particles (up to 70-wt% solubility). Their reactions with Mn3O4 particles followed Eq. 8 at 190°F, which further confirmed the absence of chlorine gas production at HCl concentrations lower than 5-wt%. EDTA and DTPA at high pH (12) and acetic, propionic, butyric, and gluconic acids at low pH (3-5) showed very low solubilities of Mn3O4 particles. GLDA, citric, oxalic, and tartaric acids produced large amount of white precipitation upon the reactions with Mn3O4 particles. Similarly, DTPA will produce damaging material if used to dissolve Mn3O4-based filter cake in sandstone formation. At 4-wt% acid concentration, lactic, glycolic, and formic acids dissolved Mn3O4 particles up to 76 wt% solubility at 190°F. Malonic acid at lower concentration (2-wt%) dissolved 54 wt% of Mn3O4 particles at 190°F. Manganese tetraoxide particles were covered with polymeric material (starch), which significantly reduced the solubility of filter cake in organic acids. Therefore, there was a need to remove Mn3O4-based filter cake in two-stage treatment. Enzyme-A (10-wt%) and Precursor of lactic acid (12.5-wt%) dissolved 84 wt% of the filter cake. An innovative approach led to complete solubility of Mn3O4 particles when low and safe concentration of HCl (1-wt%) combined with 4-wt% lactic acid at 190°F. HCl (1-wt%) combined with lactic acid (4-wt%), dissolved 85 wt% of the Mn3O4-based filter cake after 18-22 hours soaking time at 250°F in one stage treatment.
37

The Strucplot Framework: Visualizing Multi-way Contingency Tables with vcd

Meyer, David, Zeileis, Achim, Hornik, Kurt January 2005 (has links) (PDF)
This paper describes the `strucplot' framework for the visualization of multi-way contingency tables. Strucplot displays include hierarchical conditional plots such as mosaic, association, and sieve plots, and can be combined into more complex, specialized plots for visualizing conditional independence, GLMs, and the results of independence tests. The framework's modular design allows flexible customization of the plots' graphical appearance, including shading, labeling, spacing, and legend, by means of graphical appearance control (`grapcon') functions. The framework is provided by the R package vcd. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics
38

Caractérisation et simulation de la contamination et de la décontamination moléculaire des containers plastiques (FOUPs) de l'industrie microélectronique

Nguyen, Thi quynh 20 December 2012 (has links) (PDF)
Dans l'industrie des semi-conducteurs, les plaques de silicium sont stockées dans des containers, appelés FOUPs (Front Opening Unified Pod) conçus à base de matériaux polymères (PC, PEEK, COP, PEI). De tels matériaux sont capables de sorber des contaminants moléculaires volatils et de les relarguer ultérieurement en présence de plaques, entraînant de la défectivité. Cette thèse a pour but d'apporter une meilleure connaissance et compréhension de la contamination et décontamination moléculaire des FOUPs au travers de quatre axes d'étude : - La détermination de la nature, des sources et des niveaux des contaminants moléculaires des FOUPs. Les acides HF et HCl, ont été détectés au ppbv - ppmv, et apparaissent comme les contaminants critiques. - L'étude des mécanismes de sorption et dégazage de HF et HCl gazeux dans les polymères. Ils ont été caractérisés par l'établissement, pour la première fois, des coefficients de solubilité (~10-1 m3(STP).m-3. Pa-1) et de diffusion (~ 10-15 m2/s) dans les conditions industrielles (22°C, 40% RH, 1 atm). - L'évaluation expérimentale de l'efficacité du nettoyage des FOUPs par différentes méthodes de décontamination (AUD, DMS, APR) à partir de FOUPs volontairement contaminés en HF. La mise sous vide à 70°C permet de décontaminer partiellement le FOUP du contaminant piégé dans le volume du polymère tandis que le nettoyage humide ou la mise sous vide à froid ne peuvent enlever que la contamination de proche surface du FOUP. - L'établissement d'un modèle de contamination des polymères du FOUP, basé sur les lois de Fick et de Henry et utilisant les coefficients de solubilité et diffusion établis. Ce modèle a été proposé et implémenté sur Comsol Multiphysics. Pour la première fois, le comportement dynamique du contaminant dans l'atmosphère et dans les matériaux du FOUP au cours de différents événements de contamination et de décontamination du FOUP a été déterminé par simulation numérique. Ainsi, les profondeurs de diffusion de la contamination dans les polymères ont été évaluées (de quelques dizaine à centaines de µm 48 h après un événement de contamination) ou encore l'efficacité de décontamination de méthodes de nettoyage a pu être estimée.
39

The Formulation and Evaluation of Orally Disintegrating Tablets: Diphenhydramine HCl

Chillas, Stephanie M. 28 August 2013 (has links)
No description available.
40

Role of Melatonin, Neuropeptide S and Short Chain Fatty Acids in Regulation of Duodenal Mucosal Barrier Function and Motility

Wan Saudi, Wan Salman January 2015 (has links)
The duodenal epithelium is regularly exposed to HCl, digestive enzymes, bacteria and toxins, and sometimes also to ethanol and drugs. The imbalance of aggressive factors in the intestinal lumen and mucosal barrier function increases the risk of tissue injury and inflammation. The key components of the duodenal barrier function include mucosal permeability, bicarbonate transport and the secretion or absorption of fluids. This thesis aims to elucidate the role of melatonin, neuropeptide S (NPS) and short chain fatty acids (SCFAs) in the regulation of intestinal mucosal barrier function and motility in the anesthetized rat in vivo and in tissues of human origin in vitro. Melatonin was found to reduce ethanol-induced increases in paracellular permeability and motility by a neural pathway within the enteric nervous system involving nicotinic receptors. In response to luminal exposure of ethanol, signs of mild mucosal edema and beginning of desquamation were observed in a few villi only, an effect that was not influenced by melatonin. Melatonin did not modify increases in paracellular permeability in response to luminal acid. NPS decreased basal and ethanol-induced increases in duodenal motility as well as bethanechol stimulated colonic motility in a dose-dependent manner. Furthermore, NPS was shown to inhibit basal duodenal bicarbonate secretion, stimulate mucosal fluid absorption and increase mucosal paracellular permeability. In response to luminal exposure of acid, NPS increased bicarbonate secretion and mucosal paracellular permeability. All effects induced by the administration of NPS were dependent on nitrergic pathways. In rats, administration of NPS increased the tissue protein levels of the inflammatory biomarkers IL-1β and CXCL1. Immunohistochemistry showed that NPS was localized at myenteric nerve cell bodies and fibers, while NPSR1 and nNOS were only confined to the myenteric nerve cell bodies. Perfusing the duodenal segment with the SCFAs acetate or propionate reduced the duodenal mucosal paracellular permeability, decreased transepithelial net fluid secretion and increased bicarbonate secretion. An i.v. infusion of SCFAs reduces mucosal paracellular permeability without any effects on mucosal net fluid flux. However, it significantly decreased bicarbonate secretion. Luminal SCFAs changed the duodenal motility pattern from fasting to feeding motility while i.v. SCFAs was without effect on motility. The systemic administration of glucagon-like peptide-2 (GLP-2) induced increases in mucosal bicarbonate secretion and fluid absorption. An i.v. GLP-2 infusion during a luminal perfusion of SCFAs significantly reduced the duodenal motility. In conclusion, the results in the present thesis show that melatonin, NPS and SCFAs influence the neurohumoral regulation of intestinal mucosal barrier function and motility. Aberrant signaling in response to melatonin, NPS and to luminal fatty acids might be involved in the symptom or the onset of disease related to intestinal dysfunction in humans. / <p>Research funders and strategic development areas:</p><p>- Bengt Ihre Foundation (grant SLS-177521)</p><p>- Socialstyrelsen(grant SLS-176671)</p><p>- Erik, Karin, and Gösta Selanders Foundation</p><p>- Emil and Ragna Börjesson Foundation</p><p>- Uppsala University </p><p>- Ministry of Education of Malaysia</p><p>- Universiti Malaysia Sabah, Malaysia</p>

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