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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

Investigation into the origin of cavitation sounds during spinal manipulation

Beffa, Roberto January 1997 (has links)
A dissertation in partial compliance with the requirements for a Master's Degree in Technology in the Department of Chiropractic at Technikon Natal / Cavitation sounds heard during chiropractic adjustments and manipulations to th extension spine are a common phenomena yet their significance is disputed, the mechanism of their production is a matter of speculation, and their origin has never been localized. (Lewit 1978: 4, Grieve 1989; 525) The purpose of this study was to locate the joints which cavitate during the performance of a L5 spinous hook adjustment and a lower sacroiliac adjustment. It was hypothesised that the cavitation sounds would arise from the L4-L5 and L5-S1facets on the side of contact during the L5 hook adjustment., and from the the sacroiliac joint on the side being adjusted during the lower sacroiliac adjustment. It was also hypothesised that the two adjustments would differ significantly in terms of the cavitation sounds produced. Volunteers were screened for agreement with the inclusion criteria. Of these 30 asymptomatic between the ages of 18 and 30 were selected. This was sample was then randomly divided into two groups of, one of which recieved the L5 hook adjustment and the other the lower sacroiliac adjustment. All of the subjects had eight microphones taped to the skin, over the relevant facets and the sacroiliac joints. Radiographic confirmation was used in order to ensure proper positioning of the microphones. The microphones were then connected to filters, amplifiers and a computer which recorded any sound signals registered during the adjustments. / M
52

Investigations expérimentales sur les phénomènes de cavitation et d'atomisation dans les injecteurs diesel

Saliba, Ralph Champoussin, Jean-Claude. January 2006 (has links) (PDF)
Thèse de doctorat : sciences. Thermique et énergétique : Ecully, Ecole centrale de Lyon : 2006. / 91 réf.
53

Investigations expérimentales sur les phénomènes de cavitation et d'atomisation dans les injecteurs diesel

Saliba, Ralph Champoussin, Jean-Claude. January 2006 (has links) (PDF)
Thèse de doctorat : sciences. Thermique et énergétique : Ecully, Ecole centrale de Lyon : 2006. / Titre provenant de l'écran-titre. 91 réf.
54

Modélisation de l'écoulement diphasique dans les injecteurs Diesel

Dumont, Nicolas. Simonin, Olivier. January 2005 (has links)
Reproduction de : Thèse de doctorat : Dynamique des fluides : Toulouse, INPT : 2004. / Titre provenant de l'écran-titre. Bibliogr. 142 réf.
55

A computational method for evaluating cavitating flow between rough surfaces

Harp, Susan R. 05 1900 (has links)
No description available.
56

A NUMERICAL STUDY OF A NEW SPRAY APPLICATOR

Srinivasan, Vedanth 01 January 2006 (has links)
This study focuses on the design and development of a new spray applicator design utilizing effects of imposed pressure oscillations in conjunction with cavitation collapse energy to create distribution of fine droplets. An oscillating horn placed inside the nozzle performing high frequency oscillations is envisioned to provide the necessary pressure perturbations on the exiting liquid jet, while the nozzle geometry design in configured to amplify cavitation process. Initially, a two-zone approach modeling the nozzle interior and exterior in a separate fashion and later, a coupled strategy is proposed. Parametric studies describing the effect of horn stroke length, frequency, its position inside the nozzle in combination with different nozzle designs and liquid flow rates are explored to identify their contribution in obtaining desired cavitation characteristics. In this regard, incorporation of a backward facing step profile within the nozzle shows strong capability of generating the required cavitation and flow field distribution at the nozzle exit. The velocity modulations occuring at the nozzle exit due to oscillating horn structure result in a wide gamut of liquid structures specific to the imposed oscillation frequency and modulation amplitude. The disintegration characteristics of these modulated liquid jets are studied using a Volume-of-Fluid (VOF) interface capturing approach based on finite volume methodology employing an interface compression scheme. VOF methods are validated against experimental results and then subsequently used to study scaling parameters governing the modulated liquid jets. To perform coupled interior-exterior nozzle computations with cavitation, two new cavitation models are presented: First, a model based on Homogeneous Equilibrium assumptions for tracking cavitation events in a compressible framework is presented. Owing to its inability to simulate incompressible cavitating flows, a new cavitation event tracking model based on a Cavitation-Induced-Momentum-Defect (CIMD) correction approach is formulated utilizing a scalar transport model for vapor volume fraction with relevant transport, diffusion and source terms. Validations of both the models against experimental observations are detailed. Coupled internal-external liquid flow computations from the proposed atomizer design using a VOF-CIMD strategy shows strong potential for rapid drop formation in the presence of cavitation effects. A prototype model of a new spray applicator design is presented.
57

The undrained behavior of saturated, dilitant silts /

Rose, Andrew Thomas, January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Also available via the Internet.
58

Simulation numérique des signatures des sources sismiques marines et de leur interaction : application au canon à eau /

Le Mentec, Odile. January 1900 (has links)
Th. univ.--Paris VI--Géophys., 1985. / 1986 d'après la déclaration de dépôt légal. Bibliogr. p. 201-206.
59

Enhanced boiling heat transfer by submerged, vibration induced jets

Tillery, Steven W. January 2004 (has links)
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2004. / Smith, Marc K., Committee Chair ; Glezer, Ari, Committee Member ; Ghiaasiaan, S. Mostafa, Committee Member. Includes bibliographical references.
60

Transducers for measuring acoustic transients

Alcock, Robin D. January 1997 (has links)
This thesis is concerned with the design and development of measuring devices for the characterisation of acoustic transients with high temporal and spatial resolution. Three new techniques are demonstrated characterising acoustic transients generated by Nd-YAG laser (1060nm, 30ns, 55mJ) assisted breakdown of water and air. The first technique demonstrates the use of a high power semiconductor laser in a high speed multiple exposure imaging system. This system developed is capable of illuminating an event with up to 10 pulses of light at a maximum repetition rate of 5MHz, with a timing accuracy of ≈5ns. Each semiconductor laser light pulse has a FWHM duration of 50ns, peak power of 30W, and a wavelength of 860nm. Images of individual acoustic transients are displayed on the same CCD camera frame, and it was found that this is best achieved using a dark field imaging technique such as Schlieren imaging.

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