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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.
1

Inertia wave breakdown : experiments in a precessing cylinder

Manasseh, Richard January 1991 (has links)
No description available.
2

The effects of the increased use of plastics in automobiles on the technology and economics of automobile recycling in Europe

Seidl, Klaus S. January 1995 (has links)
No description available.
3

Experimental and theoretical investigations of the hydraulic shock phenomenon

Ramachandran, Paramsothynathan January 1995 (has links)
No description available.
4

Fuel Level Estimation for Heavy Vehicles using a Kalman Filter

Wallebäck, Peter January 2008 (has links)
The object with this project is to develop a more accurate way to measure the level in the fuel tank in Scaniavehicles. The level should be displayed for the driver and a warning system be implemented to make the driveraware if the fuel level is too low. Furthermore a main goal is to develop an estimation of the distance that thevehicle could travel before refueling is needed.The fuel level estimation system is modeled using Matlab Simulink and simulated with measurement datacollected from real driving scenarios. After evaluating the system it is implemented in one of the electricalcontrol units located on a test vehicle which communicates with other systems. After implementation more testsare performed with the test vehicle to verify that the same functionality achieved during simulations is achievedusing the system implemented in a vehicle.The fuel level estimated with a KF (Kalman filter) that uses fuel consumption and level measurement results ingood performance. A more stable level estimate is achieved and a negative elevation of the estimate most of thetime, as a result of fuel use. Compared to the method Scania vehicles estimate their fuel level with today thenew level estimate is more steady and not that easily affected by fuel movements. The KF is more demanding interms of memory allocation, processor speed and inputs needed, which has to be considered when comparingboth methods. Another disadvantage with the KF is that it is dependent on the samples from the fuel levelsensor to get an initial estimate during startup.Furthermore the KF is easily expanded with more inputs that use information from other sensors on other parts of the vehicle.
5

Fuel Level Estimation for Heavy Vehicles using a Kalman Filter

Wallebäck, Peter January 2008 (has links)
<p>The object with this project is to develop a more accurate way to measure the level in the fuel tank in Scaniavehicles. The level should be displayed for the driver and a warning system be implemented to make the driveraware if the fuel level is too low. Furthermore a main goal is to develop an estimation of the distance that thevehicle could travel before refueling is needed.The fuel level estimation system is modeled using Matlab Simulink and simulated with measurement datacollected from real driving scenarios. After evaluating the system it is implemented in one of the electricalcontrol units located on a test vehicle which communicates with other systems. After implementation more testsare performed with the test vehicle to verify that the same functionality achieved during simulations is achievedusing the system implemented in a vehicle.The fuel level estimated with a KF (Kalman filter) that uses fuel consumption and level measurement results ingood performance. A more stable level estimate is achieved and a negative elevation of the estimate most of thetime, as a result of fuel use. Compared to the method Scania vehicles estimate their fuel level with today thenew level estimate is more steady and not that easily affected by fuel movements. The KF is more demanding interms of memory allocation, processor speed and inputs needed, which has to be considered when comparingboth methods. Another disadvantage with the KF is that it is dependent on the samples from the fuel levelsensor to get an initial estimate during startup.Furthermore the KF is easily expanded with more inputs that use information from other sensors on other parts of the vehicle.</p>
6

Characterization of mechanical properties of advanced polymeric systems evaluated for a cryotank environment

Pavlick, Matthew Michael 05 1900 (has links)
No description available.
7

Detection of Surface Corrosion by Ultrasonic Backscattering

Retaureau, Ghislain J. 22 May 2006 (has links)
Corrosion often occurs in the inner aluminum lining of the HB-53 helicopter external fuel tank, resulting in fuel leaks. This project centers on developing an in-situ ultrasonic inspection technique to detect corroded areas inside the fuel tank. Due to the complexity of the composite structure of the tank, the ultrasonic inspection is carried out from inside the tank using a monostatic backscattering technique. The backscattered field contains information related to the insonified surface properties (surface roughness scales). Numerical predictions are implemented with a simplified model of backscattered intensity (Ogilvy, 1991). Experimental results are obtained on artificially corroded plates, and on the actual fuel tank of the HB-53 helicopter. Signal processing techniques (Envelope Correlation and Inverse Technique) are used to detect corroded surfaces with data obtained with a focused 10 MHz pulsed transducer.
8

A microchannel-based thermal management system for hydrogen storage adsorbent beds

Steigleder, Leif J. 14 June 2012 (has links)
Hydrogen has been shown to be a promising replacement for fossil fuels for use in light duty vehicles because it is a clean, renewable and plentiful resource with a high gravimetric energy density. However, in order to obtain an acceptable volumetric energy density, densification of the hydrogen is required. Adsorptive materials have been shown in the literature to increase volumetric and gravimetric storage densities. A major issue with adsorptive storage is that the adsorption process generates heat and optimal storage conditions are at temperatures below 100 K at pressures up to 50 atm. There is a need to develop heat exchanging architecture that enables adsorbents to be a viable method for hydrogen storage by managing the thermal environment of the storage tank. Based on previous modeling efforts to determine an acceptable bed module height for removal of heat via microchannel cooling plates, a thermal management system has been designed and tested capable of removing the heat of adsorption within adsorbent-filled hydrogen storage tanks. The system uses liquid nitrogen cooling to maintain tank temperatures of below 80 K at 50 atm. System studies show that the microchannel architecture offers a high cooling capacity with about a 6% displacement volume. Simulations and experiments have been conducted to evaluate the design for the cooling capacity, pressure drop, and flow distribution between and across the cooling plates, stress due to the pressurized environment, and thermal stress. Cost models have been developed to demonstrate that the system can be manufactured for a reasonable cost at high production volumes. Experimental results show that the modular system offers an acceptable cooling capacity and pressure drop with good flow distribution while adequately managing thermal stresses during operation. / Graduation date: 2013
9

Experimental characterization and mondeling of hazards, BLEVE and BOILOVER / Etude expérimentale et modélisation de phénomènes aggravants, BLEVE et BOILOVER

Laboureur, Delphine 22 November 2012 (has links)
The present thesis is conducted in the frame of a research project involving the ‘von Karman Institute (VKI Belgium)’ and the ‘Ecole des mines d’Alès (EMA France) with the support of the CEA Gramat. This project is about theoretical study, experimental characterization and modeling of hazards from pressurized or atmospheric reservoirs, containing liquids, flammable or not. <p><p>The objective of this thesis is to study the apparition criteria and the consequences of an accident involving a container of pressure liquefied gas (BLEVE phenomenon) or liquid fuels (Boilover phenomenon). After a bibliographic research on the two phenomena, an experimental study in laboratory scale is conducted and from the results, the phenomena and their hazards are modeled. Small scale experiments are performed in the BABELs facility (Bleve And Boilover ExperimentaL setup) that consists of a cylindrical chamber of 2m diameter and 3m high, with round shape flanges, made out of steel with a rated pressure of 0.5 MPa. It has 3 series of 7 optical accesses, an entrance door, and an optional air venting system. <p><p>A Boilover is a violent ejection of fuel due to the vaporization of a water sublayer, resulting in an enormous fire enlargement and formation of fireball and ground fire. Small scale experiments with cylindrical reservoirs of 0.08 to 0.3m diameter in glass or metal, filled with a mixture of diesel and oil have been performed. Instrumentation of the measurements consists of thermocouples rake, Medtherm radiometers, load cell and CCD or high-speed camera with a fisheye. During the quasi-steady combustion prior the Boilover, the typical variables describing a pool fire like burning rate, flame size, puffing frequency and radiation can be predicted with semi-empirical correlations available in the literature. At Boilover onset, high speed visualizations in glass reservoir show that the growth of one big bubble leads to a boiling front that propagates radially all along the fuel-water interface, ejecting the upper fuel layer and leading to the increase of flame size. LS-PIV technique applied to high-speed camera images shows that the flame enlargement is directly linked to the velocity of the flame.<p><p>A BLEVE (or Boiling Liquid Expanding Vapour Explosion) is an explosion resulting from the catastrophic failure of a vessel containing a liquid at a temperature significantly above its boiling point at normal atmospheric pressure. Small scale experiments are performed with cylinders of 42g of propane, laid horizontally and heated from below by an electrical resistor. A groove of the reservoirs on the upper part allows better reproducibility of the rupture. High speed visualization and shadowgraphy are helping in visualizing the rupture and the content release. Thermocouples and PCB are also used to measure respectively the temperature and the blast wave overpressure. These experiments show that the fluid behavior during rupture differs with the size of the weakened part and therefore with the rupture pressure. The internal pressure measurement showed that the rupture pressure and temperature are supercritical, leading to the definition of a new type of BLEVE since there is no distinction between liquid and vapor phases prior rupture.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
10

Konstruktionsåtgärd för lutande bränsletank / Konstruktions åtgärder för bränsleexportering vid lutning av bränsletank

Elmashaad, Farook, Abdulmageed, Ammar January 2019 (has links)
Bränsle är en viktig substans för fordon och utan bränsle så är de flesta fordon inte funktionella. I de allra flesta instruktionsböcker för fordon så rekommenderas det att bränslet inte får nå en kritisk låg nivå av bränsle. Då man talar om den kritiska bränslenivån så handlar det om ¼ kvarliggande bränsle. Då bränslet når den kritiska nivån i bränsletanken så kan problem ske och dessa problem är direkt kopplade till bränsletanken och pumpen.     Syftet med denna kandidat examensarbete är att undersöka problemet och det befintliga bränslesystemets konstruktion för att sedan generera en eller fler lösningar till problemet. Då information för detta arbete är begränsad över nätverket så skedde en del intervjuer med verkstan och fordons företag och fabriker såsom Volvo och Scania för att få en bra mängd information som sedan användes som utgångspunkt till arbetet.   För att generera lösningar till problemet med informationen som erhållits av intervjuer och andra källor så användes vissa verktyg och metoder. Då arbetet var begränsad att utföra praktiskt så utfördes den teoretiskt med hjälp av kunskaper från materiallära, hållfasthetsberäkningar, simulations program såsom AutoCAD, NASTRAN, fysik och en mängd andra ingenjörs baserat litteratur för att åstadkomma goda resultat.   Resultat blev en enkel konstruktion som är anpassat för tillverkningen av bränsletankar och som både funkar för cylindriska och rektangulära bränsletankar.   I denna rapport så presenteras resultatet i form av några förslags modeller av ett koncept som anses vara en lämplig lösning för problemet och resultat utfört med konceptet som då visar att konceptet uppfyller en fungerande lösning för det presenterade problemet. Storlek för konstruktionen presenteras i en form av enkla beräknings steg där man utgår ifrån bränsletanks modellen man vill tillämpa konceptet i. / The fuel is an important substance for vehicles and without fuel the most vehicles are not functional. In other words, they cannot move. In all instruction manuals, it is recommended that the fuel should not attain a low level in the fuel tank itself because it could lead to many consequences and these consequences are directly linked to the fuel pump and the engine itself.   The purpose of this bachelor's thesis is to investigate the issues and the existing fuel system design, then generate concepts to solve the problem. The information about the problem is limited on the world wide web, therefore we have been in contact with various truck workshops, vehicle companies and been visiting some of them. Volvo and Scania were at the top of the list. The reason was to get good and reliable information about the fuel tanks and then use it as a starting point.   Using information from interviews and sources helped very much to generate different concepts and solutions to the problem. Also, some tools and methods were very useful to build, chose and evolve the concepts. Note that some work was not performed practically because of limitations, therefore it was theoretically done with help of knowledge from different courses like materials theory, strength of materials calculations, physics, simulation programs like AutoCAD, NASTRAN and other engineering literature to achieve good results.   The result was a simple design adapted for the production of fuel tanks for the manufacture of fuel tanks, which works for both cylindrical and rectangular fuel tanks. In this report, the results are presented in the form of some proposal models and results performed with the concept, which then shows that the concept satisfies a solution to the presented problem. / <p><strong>Presentationerna genomfördes på distans med zoom</strong></p>

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