• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 7
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Assessment of injury risks associated with wearing the enhanced combat helmet and night vision goggle - driver: frontal vehicle collision study

Nakaza, Edward Takeshi, Safety Science, Faculty of Science, UNSW January 2007 (has links)
The requirement to operate vehicles in low light and/or night environments whilst wearing night vision goggle (NVG) systems has become increasingly common during military operations. There is very limited research investigating injury risks associated with these systems during ground vehicle collisions. This study examined the injury risks associated with wearing the Australian Defence Force - Enhanced Combat Helmet (ECH) and NVG system, in frontal vehicle collisions. This project consisted of two components: (1) crash tests using a sled and (2) numerical simulations of impacts. Four dynamic sled tests were conducted using a 50th percentile, male, Hybrid III dummy positioned on a rigid seat. Frontal impact tests were performed at a 40 km/h change in velocity (*v) and 20 g deceleration. The test configurations were as follows: (a) Base; (no helmet or additional equipment); (b) ECH; and, (c) ECH and NVG. Condition (c) was carried out twice, to determine repeatability. The sled test protocols were reconstructed precisely with the numerical simulation package MADYMO and the simulations were shown to correlate well with the experimental results. Using this validated model, four parametric studies were undertaken to assess the influence of counterweights, seat cushion, seatbelt pre-tensioner, and the vehicle's *v and acceleration on injury risks. The study found that neck loads were within acceptable limits, with the exception of the neck extension moment, which was exceeded for all NVG conditions. Based on the parametric studies, no major improvements were observed in the neck extension moments with the use of counterweights or a seat cushion. In contrast the use of a seatbelt pre-tensioner was observed to decrease greatly this neck injury risk in certain scenarios. The study also identified that a *v of 15 km/h and peak acceleration of up to 14 g were required to keep the neck extension moment below the prescribed injury criteria. However, the high neck extension moment values may have been partially attributable to the stiff Hybrid III neck. This study identified a possible injury mechanism for soldiers using the ECH and NVG system during specific impact scenarios. The method applied in this project was designed to be repeatable.
2

Assessment of injury risks associated with wearing the enhanced combat helmet and night vision goggle - driver: frontal vehicle collision study

Nakaza, Edward Takeshi, Safety Science, Faculty of Science, UNSW January 2007 (has links)
The requirement to operate vehicles in low light and/or night environments whilst wearing night vision goggle (NVG) systems has become increasingly common during military operations. There is very limited research investigating injury risks associated with these systems during ground vehicle collisions. This study examined the injury risks associated with wearing the Australian Defence Force - Enhanced Combat Helmet (ECH) and NVG system, in frontal vehicle collisions. This project consisted of two components: (1) crash tests using a sled and (2) numerical simulations of impacts. Four dynamic sled tests were conducted using a 50th percentile, male, Hybrid III dummy positioned on a rigid seat. Frontal impact tests were performed at a 40 km/h change in velocity (*v) and 20 g deceleration. The test configurations were as follows: (a) Base; (no helmet or additional equipment); (b) ECH; and, (c) ECH and NVG. Condition (c) was carried out twice, to determine repeatability. The sled test protocols were reconstructed precisely with the numerical simulation package MADYMO and the simulations were shown to correlate well with the experimental results. Using this validated model, four parametric studies were undertaken to assess the influence of counterweights, seat cushion, seatbelt pre-tensioner, and the vehicle's *v and acceleration on injury risks. The study found that neck loads were within acceptable limits, with the exception of the neck extension moment, which was exceeded for all NVG conditions. Based on the parametric studies, no major improvements were observed in the neck extension moments with the use of counterweights or a seat cushion. In contrast the use of a seatbelt pre-tensioner was observed to decrease greatly this neck injury risk in certain scenarios. The study also identified that a *v of 15 km/h and peak acceleration of up to 14 g were required to keep the neck extension moment below the prescribed injury criteria. However, the high neck extension moment values may have been partially attributable to the stiff Hybrid III neck. This study identified a possible injury mechanism for soldiers using the ECH and NVG system during specific impact scenarios. The method applied in this project was designed to be repeatable.
3

En jämförelse mellan två termiska saneringsmetoder : Elektrisk konduktiv uppvärmning och Elektrisk resistivitetsuppvärmning utifrån genomförda projekt i Sverige samt Nordamerika

Hultenberg, Sten January 2020 (has links)
I nuläget existerar det 85 000 områden i Sverige som är eller misstänks vara kontaminerade. Dessa områden behöver minskas för att miljökvalitetsmålet om en Giftfri miljö ska uppnås. Saneringen kan ske på olika sätt varav schaktsanering är den vanligaste. Det är en ex-situ metod som innebär att föroreningen grävs upp och förflyttas till annan plats där själva reningen sker. En annan metod är termisk in-situ sanering, vilket är när man behandlar föroreningen direkt i marken med hjälp av värme. Inom termisk behandlings brukar metoderna Elektrisk konduktiv uppvärmning (ECH) och Elektrisk resistivitetsuppvärmning (ERH) användas. ECH är en metod som beror på markens elektriska konduktivitet dvs markens förmåga att transportera elektrisk laddning. I behandlingsområdet installeras värmeelement som blir varma och sprider värmen till jorden. På så vis uppnås önskvärd temperatur och föroreningen förångas. Gasen samlas sedan upp vid markytan och renas. ERH är en metod som använder sig av elektrisk resistivitet dvs markens elektriska motståndsförmåga för att alstra värme. Elektroder installeras i behandlingsområdet som skickar ut elektrisk ström till jorden. Marken gör motstånd och värme alstras. Syftet med denna studie är att dels fördjupa sig i hur dessa metoder fungerar och att jämföra dem utifrån tekniska- och ekonomiska aspekter. Kan en av metoderna klassificeras som billigare och effektivare än den andra. En fallstudie genomfördes där sex förorenade områden med klorerande lösningsmedel studerades. Dessutom studerades tidigare undersökningar om metoderna. En statistisk bearbetning genomfördes för att se korrelationen mellan parametrarna. Utvärdering från fallstudien indikerade att det finns en stor skillnad mellan metoderna. Parametrarna: kostnad, energikonsumtion, reningseffektivitet och behandlingstid jämfördes mellan metoderna. Jämförelsen visade på att ERH har en högre kostnad, energikonsumtion och längre behandlingstid än ECH. Reningseffektiviteten är några procent högre för ECH, men båda åstadkommer över 95% rening. Däremot existerar det förutsatta meningar angående vilken metod som har högst energikonsumtion. Enligt tidigare studier påvisas det att ECH kräver mer energi än ERH vilket motsäger denna studie. Det krävs därför ytterligare undersökning för att fastställa det. Slutsatsen är därför att ECH är billigare, effektivare och snabbare än ERH.
4

Mécanismes de mise en place du matériel salifère en Tunisie septentrionale : exemples du Jebel Ech Cheid et des structures voisines

Ben Slama, Mohamed Montassar 06 June 2011 (has links) (PDF)
La structure de Jebel Ech sel Cheid est situé dans la province salifère du Nord de la Tunisie et se trouve au Sud-est du site archéologique Dogga / Téboursouk. Le rifting a commencé depuis la période triasique et s'est poursuivi au cours du Crétacé. Au début du Crétacé, ces structures ont abouti au "diapirisme" et à l'extrusion du sel dans le bassin sédimentaire. Dans les deux flancs du Jebel Ech Cheid, nous avons observé des preuves de la manifestation de la tectonique synsédimentaires tel que : failles normales sellé dans les dépôts albiennes, slumps, olistolithes, remaniements du matériel salifères dans les sédiments barrémiennes et albiennes.... Dans la période Jurassique/Crétacé inférieur la subsidence est importante et elle est lié principalement à l'amorce des mouvements du salifère triasique dans la région du Jebel Ech Cheid. Par la suite, l'épisode extensive majeur est installée depuis l'Aptien jusqu'au Sénonien inférieur. L'architecture du bassin sédimentaire est ordonnancée par des systèmes de failles héritées identifié par l'intermédiaire de profiles sismiques : il s'agit d'un système de rollover synthétique et antithétiques dans le bassin méridionale du corps salifère associé avec le mouvement de la failles de Téboursouk dans le flanc septentrionale.L'architecture du bassin sédimentaire construite aux cours du Mésozoïque été le principale facteur responsable à la naissance de la structure du Jebel Ech Cheid. Ensuite, la phase de compression majeure a été provoquée vers la fin du Crétacé supérieur et atteint son paroxysme à l'Eocène supérieur. Ainsi au cours de l'Oligocène il y a une période d'étirement. Enfin, les mouvements du salifère ont été influencés par les plissements tortoniennes et quaternaires. La délamination et les plissements des sédiments de couverture du matériel salifère a facilité le développement des ailes de sel. La structure salifère du Jebel Ech Cheid a été soumise à des forces compressives asymétriques édifiant des chevauchements sur les bordures, éventuellement renforcé par la gravité en raison de l'orientation des grandes failles normales héritées (NE-SW) et le rôle de la direction principale de compression (NW-SE). Par conséquent, la combinaison des mouvements chevauchement/décrochement dextre a donné naissance à une structure en queue de cheval bien visible dans le bassin de Gafour durant l'épisode du Quaternaire. Ainsi, nous considérons le corps salifère du Jebel Ech Cheid comme un dôme de sel avec des extrusions pulsatiles de sel à l'image d'un "glacier" de sel. Dans une période initiale à l'Aptien supérieur les abords de la structure sont à 451m et le taux d'extrusion de la masse de sel sur le fond de la mer a été calculée avec la méthode de Talbot est de l'ordre de 55,2 mm an-1. Il est également plus de 400 fois plus rapide que la vitesse de sédimentation la plus rapide des sédiments de couverture terminé en moyenne vers les 9 Ma du Barrémien/Aptien. Le dôme de sel a été ensuite enraciné et il a évolué vers une structure complexe qui a été déracinée après les plissements tertiaires et quaternaires. Au Nord de la Tunisie, près de Testour/Slouguia, nous avons conduit de nouvelles observations et révision biostratigraphique. À la lumière de ces apports, il est possible de mieux interpréter la relation entre le sel triasique et les séries mésozoïques encaissantes (T.M.). Auprès de la limite (T.M.), le matériel salifère se trouve remanié dans la série marno-argileuse de l'Albien inférieur. Dans tout le secteur, nous avons noté la quasi-absence du Jurassique. Nous proposons d'interpréter la mise en place du sel triasique de la structure de Chitana-Ed Djebes, d'une manière gravitationnelle dans une marge passive à l'Albien, à l'image des corps salifères de la province salifère du Golf Coast du Mexique. Un schéma rétro-tectonique de la structure salifère Chitana-Ed Djebs montre que cette mise en place s'est effectuée sur une paléo-pente sous-marine. En outre, on établit les indices de l'amorce de l'inversion tectonique post Campanien et son paroxysme de l'Éocène moyen à supérieur. Cette dernière est clairement fossilisée par la discordance de l'Eocène moyen-Lutétien sur les séries albiennes.
5

An Electrolytic Method to Form Zirconium Hydride Phases in Zirconium Alloys with Morphologies Similar to Hydrides Formed in Used Nuclear Fuel

Kuhr, Samuel Houston 2012 August 1900 (has links)
An electrolytic cell was designed, built, and tested with several proof-of-concept experiments in which Zircaloy material was charged with hydrogen in order to generate zirconium hydride formations. The Electrolytic Charging with Hydrogen and a Thermal Gradient (ECH-TG) system has the ability to generate static 20°C to 120°C temperatures for a H2SO4 and H2O bath for isothermal experiment conditions. This system was designed to accommodate a molten salt bath in future experiments to achieve higher isothermal temperatures. Additionally, the design accommodates a cartridge heater, which when placed on the inside of the sample tube, can be set at temperatures up to 350 °C and create a thermal gradient across the sample. Finally, a custom LABVIEW VI, L2.vi, was developed to control components and record data during experimentation. This program, along with web cameras and the commercial StirPC software package, enables remote operation for extended periods of time with only minor maintenance during an experiment. While proving the concept for this design, 19 experiments where performed, which form the basis for a future parametric study. Initial results indicate formations of zirconium hydrides which formed rim structures between 8.690 +/- 0.982 μm and 12.365 +/- 0.635 μm thick. These electrolytically produced rims were compared with hydrides formed under a previous vapor diffusion experiment via Scanning Electron Microscope (SEM) imaging and Energy dispersive X-ray Spectroscopy (EDS) analysis. While the existing vapor diffusion method formed gradients of zirconium hydride, it failed to produce the gradient in the correct direction and also failed to create a hydride rim. The successful use of the ECH-TG system to create said rim, and some of the methods used to direct that rim to the OD of the tube can be used for future work with the vapor diffusion method in order to create zirconium hydrides of the correct geometry. The procedures and apparatus created for this project represent a reliable method for creating zirconium hydride rim structures.
6

Analýza součinnosti spojka - pivot na ME 2008 dorostenců v házené / Qualitative analysis of cooperation of back court player and line player on the 9th Men's European Championship in Brno

Václavek, Ondřej January 2011 (has links)
Title: Qualitative analysis of cooperation of back court player and line player on the 9th Men's "18" European Championship in Brno. Objectives: Qualitative analysis of the attacking combinations between back court player and line player on the 9th Men's "18" European Championship 2008 in Brno, finding out the space distribution of these combinations and compare the trend analysis of Men's "18", Men's "20" and Men's European Championship. Methods: Qualitative Analysis of the matches on DVD with using non participating and non structured observing connected with quantitative analysis based on the statistical program Handball Stat. We used own form for recording the observed data. Results: The teams used combination based on passing mostly. The distribution of co-operation probably depended on physical, technical and tactical preparation of the back court players and through that the line player very often co-operated with left and middle back. Key words: handball, combination, co-operation, back court player, line player, qualitative analysis, 9th Men's "18"ECh 2008 Brno
7

Internationalism and Nationalism in Smetana’s <i>Brandenburgers</i> and <i>Libuše</i>

St. Pierre, Kelly M. 12 May 2009 (has links)
No description available.

Page generated in 0.0195 seconds