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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.
51

Zdravotně technické a plynovodní instalace v tělocvičně / The Sanitation installations and gas installations in a gym

Křoustek, Jiří January 2013 (has links)
The thesis deals with the topic of the Sanitation installations and gas installations in a gym. The core element of the theoretical part is the water saving while using the economical fixture in the building. The following point is the financial estimation. The thesis also deals with various options of solving the scheduled specialisation. Here, the two ways of proportioning and two ways of mixing the hot water for taking a shower are described in detail. The project part is trying to solve the sanitary technical and gas pipeline in a gym in the chosen version.
52

Unsteady flow conditions at dam bottom outlet works due to air entrainment during gate closure : Berg River dam model

Vos, Adele 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: A trial closure of the emergency gate of the Berg River Dam was undertaken by the Trans- Caledon Tunnel Authority (TCTA) on 12 June 2008. The air vent downstream of the emergency gate was designed to introduce air to mitigate the negative pressures that were expected in the conduit during emergency gate operations. The emergency gate has to close when the radial gate at the downstream end of the outlet conduit fails. Contrary to the theoretical design, the measured air vent velocities in the field indicated that, while the emergency gate was closing, very large volumes of air were apparently continuously being released from the air vent, commencing when the gate was about 30% closed (i.e. 70% open). This is in contrast to what the design intended, namely that air should have been drawn into the vent. This thesis is concerned with the testing of a 1:14.066 physical model representing the outlet works and air vent of the Berg River Dam as a means to determine the reasons for the release of large volumes of air from the air vent during the trial closure in 2008. It also seeks solutions to mitigate the excessive airflow from the air vent. It was concluded that the air velocity in the air vent was independent of the rate of closure of the emergency gate, but to increase with increasing water head. The problem at the Berg River Dam was determined to be one of air blowback. Modifications were made to the configuration of the model in order to determine whether the configuration of the outlet works caused air to be released from the air vent. It was determined that the downward sloping roof at the outlet of the conduit, used to accommodate the radial gate chamber, was the cause of the air blowback phenomenon. An additional air vent was fitted directly onto the conduit at the constriction was found to be ineffective in reducing the air blowback. It was concluded that there are no rational structural change that can prevent or inhibit a recurrence of the blowback phenomenon in the Berg River Dam outlet conduit. The recommendation follows that the outlet conduit should not be constricted by any structural or mechanism further downstream in the conduit. / AFRIKAANSE OPSOMMING: ʼn Toetssluiting van die noodsluis van die Bergrivierdam is op 12 Junie 2008 deur die TCTA (Trans-Caledon Tunnel Authority) uitgevoer. Die lugskag stroomaf van die noodsluis is ontwerp om lug in te voer om die verwagte negatiewe drukke tydens die noodsluissluiting te beperk. Die noodsluis moet sluit indien die radiaalsluis aan die einde van die uitlaatpyp sou faal. In teenstelling met die teoretiese ontwerp, het die gemete lugsnelhede in die lugskag in die veld aangedui dat groot volumes lug voortdurend uit die lugskag vrygelaat word wanneer die noodsluis ongeveer 30% toe is (dit wil sê 70% oop). Dit is in teenstelling met die ontwerp, want die lugskag is ontwerp vir die insuig van lug. Hierdie tesis het ten doel om die redes vir die vrylating van groot volumes lug uit die lugskag vas te stel met behulp van ʼn 1:14.066 fisiese skaalmodel van die uitlaatwerke en lugskag van die Bergrivierdam soos getoets tydens die inwydingstoetssluiting in 2008. Die toetse op die model het getoon dat die lugsnelheid in die lugskag onafhankik van die sluistoemaak tyd is, maar verhoog met die toename in die watervlak. Die Bergrivier dam probleem was bepaal as die van lug terugslag. Die model is gewysig ten einde te bepaal of die spesifieke samestelling van die uitlaatwerke die oorsaak van die vrystelling van lug uit die lugskag is. Die analises en verandering aan die uitleg toon aan dat die skuins afwaartse dak van die uitlaattonnel om die radiaalsluiskamer te huisves die rede was vir die vrylating van die lug uit die lugskag. ‘n Addisionele lugskag was gebou in die dak van die uitlaattonnel reg bo die sametrekking, maar was oneffektief om die terug vloei van lug te verminder. Die gevolgtrekking is dat daar geen rasionele strukturele verandering aangebring kan word aan die Bergrivier dam om die vrystelling van lug uit die lugskag te verhoed of te verminder nie. ’n Aanbeveling vir toekomstige ontwerpe is dus dat die uitlaattonnel nie beperkend by die uitlaatend moet wees nie.
53

Investigations of Pile Foundations in Brownfields

Satyamurthy, Ranjan 20 May 2005 (has links)
"Brownfields" are real estate property with subsurface or surface contamination. The redevelopment of Brownfields is required to clean, improve and protect the environment. Piles foundations are often used in Brownfields to support structures. Regulators are concerned about the environmental safety of pile foundations in Brownfields sites. Piling in Brownfields may lead to transport of contaminants from the contaminated region to the underground aquifers. The purpose of this investigation is to determine the potential for contaminant transport due to pile foundation in Brownfields. This investigation is an extension of previous research conducted at the University of New Orleans and ascertains the potential for contaminant transport from concrete piles of different shape, depth of penetration and method of installation. The results of large scale model tests and Finite Element studies are presented. The investigation indicates the possibility of contamination only in selected cases of piles.
54

Früher und mittelfristiger Verlauf nach Fontan-Operation

Ovrutskiy, Stanislav 22 October 2004 (has links)
Im Rahmen einer vergleichenden retrospektiven Analyse wurden die präoperativen und intraoperativen Einflussfaktoren auf den frühen und mittelfristigen postoperativen Verlauf nach Fontan-Operation untersucht und die Ergebnisse der totalen cavopulmonale Anastomose mit einem intraatrialen lateralen Tunnel (LTFO, n = 25) und mit einem extrakardialen Kunststoff-Konduit (ECFO, n = 25) gegenüber gestellt. Postoperativ wurde nach ECFO ein komplikationsärmerer früher Verlauf mit kürzerer maschineller Beatmung und signifikant geringerer Inzidenz für frühe und mittelfristige Arrhythmien als nach LTFO beobachtet. Im frühen postoperativen Verlauf waren die schnellste Extubation und Entlassung bei den ECFO-Patienten möglich, bei denen keine Kardioplegie verwendet wurde. Unabhängige Risikofaktoren nach multivariater Analyse waren die Dauer der Kardioplegie in Bezug zu den unmittelbaren postoperativen Komplikationen, eine LTFO - sowohl für Tachy- als auch für Bradyarrhythmien - und die Inzision in die cavoatriale Verbindung bei LTFO in Bezug zu Bradyarrhythmien mit der Notwendigkeit einer Schrittmacherimplantation. Durch Vermeidung von Kardioplegie und chirurgischer Schaffung eines lateralen Tunnels sowie Verkürzung des kardiopulmonalen Bypasses bei ECFO werden vor allem die postoperativen Arrhythmien reduziert und es ist wahrscheinlich möglich, den postoperativen Verlauf bei Patienten mit einem durch eine langwierige Zyanose und durch Volumenbelastung vorbeschädigten singulären Ventrikel zu verbessern. Eine prospektive langfristige Vergleichsstudie mit einer größeren Patientenzahl ist notwendig, um die Frage zu beantworten, ob eine signifikante Minderung der spätpostoperativen Komplikationen und eine Verbesserung der Lebenserwartung der Patienten mit univentrikulärer Physiologie durch eine korrekt geplante und optimal durchgeführte extrakardiale Modifikationen der Fontan-Operation erreicht werden kann. / The preoperative and intraoperative risk factors for early and mid-term postoperative course after Fontan operation were analyzed and results after total cavopulmonary connection with lateral intraatrial tunnel (LTFO, n = 25) and with extracardiac conduit (ECFO, n = 25) were compared retrospectively. The early postoperative course after ECFO was better with shorter duration of mechanical ventilation. Lower incidence of arrhythmias was observed after ECFO compared to LTFO both early postoperatively and during mid-term follow-up. Patients after ECFO, in whom cardioplegia was not used intraoperatively, had the shortest duration of mechanical ventilation and of the hospital stay. Multivariate analysis revealed duration of cardioplegia as an independent risk factor for early postoperative complications, LTFO as a risk factor for tachyarrhythmias and incision into the cavoatrial junction during LTFO as a risk factor for the bradyarrhythmias requiring pacemaker implantation. With the avoidance of cardioplegia and intracardiac surgery and shorter cardiopulmonary bypass times during ECFO, postoperative arrhythmias could be reduced. Further, the early postoperative course in patients with univentricular physiology who have had cyanosis and ventricular volume overload for a long time seems to be better after extracardiac modification of Fontan operation. To investigate whether late complications are reduced by optimal extracardiac Fontan operation and whether life expectancy in patients with single ventricle is improved, long-term prospective comparative follow-up studies are needed.
55

Approche numérique pour le calcul de la matrice de diffusion acoustique : application pour les cas convectifs et non convectifs / A numerical approach for the calculation of the acoustical scattering matrix : application for the convective and the non-convective cases

Kessentini, Ahmed 01 July 2017 (has links)
La propagation acoustique guidée est étudiée dans ce travail. La propagation des ondes acoustiques dans une direction principale est privilégiée. La méthode des éléments finis ondulatoires est donc exploitée pour extraire les nombres d'ondes. Les déformées des différents modes de conduit rigide sont aussi obtenues. Pour des conduits avec des discontinuités d'impédance, la matrice de diffusion peut être calculée à l'aide d'une modélisation par éléments finis de la partie traitée acoustiquement. Une modélisation tridimensionnelle des conduits traités acoustiquement permet une étude de la propagation pour tous les ordres des modes, de leur diffusion et du comportement acoustique des matériaux absorbants. Les réponses forcées de diverses configurations de guides d'ondes aux conditions aux limites imposées sont également calculées. L'étude est finalement étendue à la propagation acoustique dans les guides d'ondes avec un écoulement moyen uniforme. / The guided acoustical propagation is investigated in this work. The propagation of the acoustic waves in a main direction is privileged. A Wave Finite Element method is therefore exploited to extract the wavenumbers. Rigid duct's mode shapes are moreover obtained. For ducts with impedance discontinuities, the scattering matrix can be then calculated through a Finite Element modelling of the lined part. A three dimensional modelling of the lined ducts allows a study of the propagation for the full modes orders, their scattering and the acoustic behaviour of the absorbing materials. The forced responses of various configurations of waveguides with imposed boundary conditions are also calculated. The study is finally extended to the acoustical propagation within waveguides with a uniform mean flow.
56

Étude d'un modèle continu des cordes vocales sous forme de deux poutres bi-articulées : premières simulations

Perrier, Pascal 08 December 1982 (has links) (PDF)
.
57

Characterization of High-PGE Low-Sulphur Mineralization at the Marathon PGE-Cu Deposit, Ontario

Ruthart, Ryan January 2013 (has links)
The Marathon PGM-Cu deposit is hosted by the Coldwell alkaline complex, which consists predominantly of gabbro and syenite and was emplaced at 1108 Ma as part of the Mid-Continent Rift System. Mineralization at the Marathon PGM-Cu deposit is hosted by the Two Duck Lake Gabbro (TDLG), a fresh olivine-bearing gabbro. The Marathon deposit contains several zones of mineralization including the Basal Zone, the Main Zone and the W-Horizon. The W-Horizon is a high-grade PGE zone characterized by low S, low Cu/Pd and high Cu/Ni. The sulphide mineral assemblage is predominantly chalcopyrite and bornite. This contrasts with the Main Zone where the dominant sulphide mineral assemblage is chalcopyrite and pyrrhotite. The Main Zone contains higher S, higher Cu/Pd and shows a decrease in Cu/Pd and pyrrhotite/chalcopyrite from base to top. Four drill holes were selected for detailed analysis to characterize the W-Horizon style of mineralization. Detailed petrographic study of the pristine and largely unaltered TDLG shows that wide spread hydrothermal alteration is not responsible for the mineralization. Detailed outcrop mapping shows that the TDLG intruded as a series of multiple intrusions in a dynamic magmatic system. Geochemical studies through the W-Horizon show that the mineralization is not the result of crystallization in a layered intrusion. The results of geochemical assays and electron microprobe analysis of olivine grains show that the chemistry through the TDLG hosting the W-Horizon is erratic. This data supports the TDLG intruding as a series of sills in a dynamic conduit environment. The calculated sulphide metal tenors for the W-Horizon are higher than can be explained by closed system R Factor models. Multistage dissolution upgrading in an open system is examined as the process forming the W-Horizon. This model is able to produce the sulphide metal tenors observed in the W-Horizon. Sulphur loss also affects grades and tenors and was examined through geochemical and petrological data. The change in sulphide mineral assemblage from a pyrrhotite and chalcopyrite (S-rich) to chalcopyrite and bornite (S-poor) supports S-loss. Whole rock S and Se contents are also analyzed to investigate S loss, a lower S/Se indicates that sulphur has been removed from the system. Average S/Se values are ~800 for the W-Horizon, ~1980 for the Main Zone and ~1700 in unmineralized samples. The very low S/Se observed within the W-Horizon supports S-loss. Sulphur loss in a dynamic magmatic conduit system is proposed for the formation of the W-Horizon mineralization. In this model sulphur undersaturated basaltic magma interacted with an immiscible sulphide liquid in a magma conduit, resulting in the dissolution of sulphide into the basaltic melt and PGE enrichment.
58

Adaptation de clones orofaciaux à la morphologie et aux stratégies de contrôle de locuteurs cibles pour l'articulation de la parole

Valdes, Julian 28 June 2013 (has links) (PDF)
La capacité de production de la parole est apprise et maintenue au moyen d'une boucle de perception-action qui permet aux locuteurs de corriger leur propre production en fonction du retour perceptif reçu. Ce retour est auditif et proprioceptif, mais pas visuel. Ainsi, les sons de parole peuvent être complétés par l'affichage des articulateurs sur l'écran de l'ordinateur, y compris ceux qui sont habituellement cachés tels que la langue ou le voile du palais, ce qui constitue de la parole augmentée. Ce type de système a des applications dans des domaines tels que l'orthophonie, la correction phonétique et l'acquisition du langage. Ce travail a été mené dans le cadre du développement d'un système de retour articulatoire visuel, basé sur la morphologie et les stratégies articulatoires d'un locuteur de référence, qui anime automatiquement une tête parlante 3D à partir du son de la parole. La motivation de cette recherche était d'adapter ce système à plusieurs locuteurs. Ainsi, le double objectif de cette thèse était d'acquérir des connaissances sur la variabilité inter-locuteur, et de proposer des modèles pour adapter un clone de référence, composé de modèles des articulateurs de la parole (lèvres, langue, voile du palais, etc.), à d'autres locuteurs qui peuvent avoir des morphologies et des stratégies articulatoires différentes. Afin de construire des modèles articulatoires pour différents contours du conduit vocal, nous avons d'abord acquis des données qui couvrent l'espace articulatoire dans la langue française. Des Images médio-sagittales obtenues par Résonance Magnétique (IRM) pour onze locuteurs francophones prononçant 63 articulations ont été recueillis. L'un des principaux apports de cette étude est une base de données plus détaillée et plus grande que celles disponibles dans la littérature. Cette base contient, pour plusieurs locuteurs, les tracés de tous les articulateurs du conduit vocal, pour les voyelles et les consonnes, alors que les études précédentes dans la littérature sont principalement basées sur les voyelles. Les contours du conduit vocal visibles dans l'IRM ont été tracés à la main en suivant le même protocole pour tous les locuteurs. Afin d'acquérir de la connaissance sur la variabilité inter-locuteur, nous avons caractérisé nos locuteurs en termes des stratégies articulatoires des différents articulateurs tels que la langue, les lèvres et le voile du palais. Nous avons constaté que chaque locuteur a sa propre stratégie pour produire des sons qui sont considérées comme équivalents du point de vue de la communication parlée. La variabilité de la langue, des lèvres et du voile du palais a été décomposé en une série de mouvements principaux par moyen d'une analyse en composantes principales (ACP). Nous avons remarqué que ces mouvements sont effectués dans des proportions différentes en fonction du locuteur. Par exemple, pour un déplacement donné de la mâchoire, la langue peut globalement se déplacer dans une proportion qui dépend du locuteur. Nous avons également remarqué que la protrusion, l'ouverture des lèvres, l'influence du mouvement de la mâchoire sur les lèvres, et la stratégie articulatoire du voile du palais peuvent également varier en fonction du locuteur. Par exemple, certains locuteurs replient le voile du palais contre la langue pour produire la consonne /ʁ/. Ces résultats constituent également une contribution importante à la connaissance de la variabilité inter-locuteur dans la production de la parole. Afin d'extraire un ensemble de patrons articulatoires communs à différents locuteurs dans la production de la parole (normalisation), nous avons basé notre approche sur des modèles linéaires construits à partir de données articulatoires. Des méthodes de décomposition linéaire multiple ont été appliquées aux contours de la langue, des lèvres et du voile du palais. L'évaluation de nos modèles repose sur deux critères: l'explication de la variance et l'erreur quadratique moyenne. Les modèles ont également été évalués en utilisant une procédure de validation croisée. Le but de l'utilisation de telle procédure était de vérifier la capacité de généralisation des modèles en évaluant leurs performances sur des données qui n'ont pas été utilisées pour leur construction. Afin de modéliser la langue, les lèvres et le voile du palais avec un ensemble commun de composantes pour tous les locuteurs, plusieurs méthodes de décomposition linéaires multiple ont été utilisées et comparées. L'ACP conjointe a donné les meilleurs résultats. En conclusion, nous avons constaté une réduction considérable en termes de nombre de composantes nécessaires lors de l'utilisation d'ACP conjointe, par rapport au nombre total de composantes nécessaires par les modèles ACP individuels de tous les locuteurs. Ces résultats de modélisation constituent une extension importante des études disponibles dans la littérature, à des locuteurs plus nombreux, incluant de plus nombreuses articulations (en particulier les consonnes) et de plus nombreux articulateurs (lèvres, voile du palais).
59

Multiwalled Carbon Nanotube- Poly(2-hydroxyethyl Methacrylate) Composite Conduitfor Peripheral Nerve Repair

Arslantunali, Damla 01 March 2012 (has links) (PDF)
There are different methods used in the surgical treatment of peripheral nerve injury. In this respect, end-to-end surgical reconnection of the damaged nerve ends or autologous nerve grafts are applied as soon as possible after the injury. When autologous tissue transplant is considered, there are some medical devices available generally for relatively short nerve defects. As a solution for this problem, different tissue engineered nerve conduits have been developed. In the current study, a pHEMA hydrogel membranes were designed to mimic the tubular conduits and they were loaded with 1-6% (w/w) multiwalled carbon nanotubes (mwCNTs) to obtain electrical conductivity. The most important reason for the use of CNTs in peripheral nerve injury is their electrical conductivity. Within the context of the study, the degree of swelling, contact angles, electrical conductivity and mechanical properties of the membranes were analyzed. As the amount of mwCNTs were increased, the contact angles, indicating higher hydrophobicity and the electrical conductivity increased. The tensile test of the mwCNT-pHEMA composite membranes showed that the membranes have viscoelastic structure similar to the structure of the soft tissues. The structure of the mwCNT containing pHEMA composite membranes were analyzed with different microscopical techniques such as SEM, CSLM and microCT. MwCNTs on the hydrogels were morphologically similar to the original. SEM micrographs also showed that the mwCNTs were grouped in clumps on hydrogel surfaces. No mwCNT leaching was observed because the mwCNTs were embedded in the hydrogel, therefore, no cytotoxic effect was observed. The pHEMA hydrogels were porous which is suitable for transportation of materials, electrolytes and gas needed for cell nutrition and growth. In the in vitro studies, SHSY5Y neuroblastoma cells were seeded on the membranes to determine the sustainability and effects of the membranes on the cell growth. Electrical potential of 1 and 2 V were used to stimulate the cells. Microscopical examination with SEM and CSLM, and MTT viability assay were used. The SHSY5Y neuroblastoma cells were attached and proliferated on both the composite and the hydrogel membranes. The cells on pHEMA membranes without mwCNTs, however, were not able to survive after application of electrical potential. As a conclusion, use of composite membranes in the treatment of peripheral nerve injury as a nerve conduit is appropriate. Electrical stimulation, however, did not induce the cells to align in contrast to the expected results, indicating potential and current application regime needs to be optimized to obtain the desired results.
60

Biosynthetic conduits and cell transplantation for neural repair

Pettersson, Jonas January 2011 (has links)
Spinal cord injury results in complete failure of the central neurons to regenerate and is associated with cyst formation and enlargement of the trauma zone. In contrast to the spinal cord, axons in the injured peripheral nerve have the capacity to undergo some spontaneous regeneration. However, significant post-traumatic loss of nervous tissue causing long nerve gap is one of the main reasons for the poor restoration of function following microsurgical repair of injured nerves. The present thesis investigates the effects of biodegradable conduits prepared from fibrin glue and poly-beta-hydroxybutyrate (PHB) in combination with cultured Schwann cells, mesenchymal stem cells and extracellular matrix molecules on regeneration after spinal cord and peripheral nerve injury in adult rats. At 4-8 weeks after transplantation into the injured spinal cord, the PHB conduit was well integrated into the cavity but regenerating axons were found mainly outside the PHB. When suspension of BrdU-labeled Schwann cells was added to the PHB, regenerating axons filled the conduit and became associated with the implanted cells. Modification of the PHB surface with extracellular matrix molecules significantly increased Schwann cell attachment and proliferation but did not alter axonal regeneration. To improve the labeling technique of the transplanted cells, the efficacy of fluorescent cell tracers Fast Blue, PKH26, Vibrant DiO and Cell Tracker™ Green CMFDA was evaluated. All tested dyes produced very efficient initial labeling of olfactory ensheathing glial cells in culture. The number of Fast Blue-labeled cells remained largely unchanged during the first 4 weeks whereas the number of cells labeled with other tracers was significantly reduced after 2 weeks. After transplantation into the spinal cord, Fast Blue-labeled glial cells survived for 8 weeks but demonstrated very limited migration from the injection sites. Additional immunostaining with glial and neuronal markers demonstrated transfer of the dye from the transplanted cells to the host tissue. In a sciatic nerve injury model, the extent of axonal regeneration through a 10mm gap bridged with tubular PHB conduit was compared with a fibrin glue conduit. At 2 weeks after injury, the fibrin conduit supported similar axonal regeneration and migration of the host Schwann cells compared with the PHB conduit augmented with a diluted fibrin matrix and GFP-labeled Schwann cells or mesenchymal stem cells. The long-term regenerative response was evaluated using retrograde neuronal labeling. The fibrin glue conduit promoted regeneration of 60% of sensory neurons and 52% of motoneurons when compared with the autologous nerve graft. The total number of myelinated axons in the distal nerve stump in the fibrin conduit group reached 86% of the nerve graft control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89%, respectively. When a fibrin conduit was used to bridge a 20mm sciatic nerve gap, the weight of gastrocnemius muscle reached only 43% of the nerve graft control. The morphology of the muscle showed more chaotic appearance and the mean area and diameter of fast type fibers were significantly worse than those of the corresponding 10mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. In summary, these results show that a PHB conduit promotes attachment, proliferation and survival of adult Schwann cells and supports marked axonal growth after transplantation into the injured spinal cord. The data suggest an advantage of the fibrin conduit for the important initial phase of peripheral nerve regeneration and demonstrate potential of the conduit to promote long-term neuronal regeneration and muscle recovery.

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