• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 497
  • 244
  • 116
  • 55
  • 33
  • 23
  • 18
  • 10
  • 8
  • 7
  • 4
  • 4
  • 4
  • 3
  • 3
  • Tagged with
  • 1268
  • 193
  • 163
  • 161
  • 141
  • 132
  • 112
  • 102
  • 102
  • 101
  • 96
  • 90
  • 89
  • 88
  • 79
  • 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.
71

Prospects of lean ignition with the quarter wave coaxial cavity igniter

Pertl, Franz Andreas Johannes, January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xi, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 48-51).
72

A comparative investigation of the root number and canal anatomy of permanent teeth in a Southern Chinese population /

Walker, Richard Thomas. January 1987 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1987.
73

Localization of Near-Surface Anomalies Using Seismic Rayleigh Waves

Xu, Chao Qiang 15 April 2010 (has links)
The presence of subsurface anomalies, such as cavities, faults, unknown tunnels, etc., either natural or man-made, can cause public safety hazards. The detection of these features requires the development of new methods. Seismic Rayleigh surface wave imaging is a relatively new non-destructive testing technique (NDT) which generates subsurface images without drilling boreholes into the ground, and in recent years has been widely used for soil characterization in geotechnical investigations. In the last decade, some researchers have applied the technique to near-surface imaging and showed the possibility and potential for engineering applications. This research presents the development of a technique to process seismic Rayleigh waves to detect and image subsurface anomalies. This study conducted investigations of Rayleigh wave behaviors and developed a new strategy for Rayleigh wave isolation from raw field data. The strategy applies wavelet transforms, instead of the conventional spectral analysis of surface waves (SASW) method, or popular multichannel analysis of surface waves (MASW) techniques, to pair-channel analysis of the isolated Rayleigh wave data for dispersion calculation. Finally, a simple steady inversion technique was applied to yield shear velocity as a function of both depth and distance, and shear velocity field images (SVF), for near surface section display. This research consists of development, computer programming, field tests, data processing and interpretation. Three sites in different scenarios were used for seismic investigations: old mining tunnels in medium dipping coal seams in Stellarton coalfield, mining cavities in steeply dipping gold-bearing veins in West Waverley Gold District and an anomaly in nearly horizontal strata in Liverpool. All these sites are in the province of Nova Scotia, Canada. The results from seismic surface wave technique introduced in this research can be evaluated by field observations, documents and borehole logs. The satisfactory interpretations and success of this investigation shows that this technique is suitable for engineering application for subsurface investigations.
74

The development of a vibrating wire viscometer and a microwave cavity resonator for the measurement of viscosity, dew points, density, and liquid volume fraction at high temperature and pressure.

Kandil, Mohamed E. January 2005 (has links)
This thesis describes the development and testing of two apparatuses; a vibrating wire viscometer to measure the viscosity of fluids over a wide range of temperature and pressure; and a microwave cavity resonator to measure dew points, gas phase densities, and liquid drop out volumes. Viscosity and density of downhole fluids are very important properties as their values can determine the economic viability of a petroleum reservoir. A vibrating wire viscometer has been developed with an electrically insulating tensioning mechanism. It has been used with two wires, of diameters (0.05 and 0.150) mm, to measure the viscosity of methylbenzene and two reference fluids with viscosities of (10 and 100) mPa·s at T = 298 K and p = 0.1 MPa, at temperatures in the range (298 to 373) K and pressures up to 40 MPa, where the viscosity covers the range (0.3 to 100) mPa·s, with a standard uncertainty < 0.6 %. The results differ from literature values by < ±1 %. The results demonstrate that increasing the wire diameter increases the upper operating viscosity range of the vibrating wire viscometer, a result anticipated from the working equations. For the microwave cavity resonator, the method is based on the measurements of the resonance frequency of the lowest order inductive-capacitance mode. The apparatus is capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure the dew pressures of {0.4026CH4 + 0.5974C3H8} at a temperature range from 315 K up to the cricondentherm ˜ 340 K. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that have quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within < ±1 % of the present results at temperature between (315 and 337) K while predictions obtained from the Soave-Redlich-Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K. Densities derived from dielectric permittivity measurements in the gas phase lie within < 0.6 % of the values calculated from the Soave-Redlich-Kwong cubic equation of state and about 1 % from values obtained with the Harvey and Prausnitz correlation based on a mixture reduced density. The calculations with Kiselev and Ely parametric crossover equation of state (based on Patel-Teja EOS) gave deviations < 0.7 %. Liquid volume fractions, in the 2-phase region, were measured from (0.5 to 7) cm3 in a total volume of about 50 cm3 at different isochors. The measured liquid volume fractions differ from values obtained with the Soave-Redlich-Kwong cubic equation of state by between 0 and 3 % at T < 326 K and about 8 % on approach to the critical region. The large deviations observed in the critical region were anticipated because of the known poor performance of the cubic equations of state with regard to the calculation of the liquid density in the vicinity of the critical temperature.
75

Nitrate reduction by oral bacteria : a role in host defence against pathogens?

Li, Hong January 2001 (has links)
No description available.
76

Cavity growth mechanism maps

Perryman, L. J. January 1988 (has links)
No description available.
77

The mechanical principles of cavity preparation for posterior cast gold restorations : to be presented as section A - Review of the literature, section B -Original contribution

Hyde, P. F January 1985 (has links)
Master of Dental Surgery / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au
78

Evaluation of the effects of rotary instrument design on internal line angles of cavity preparations and enamel rod direction relative to different concepts of cavity design

Todescan, Reynaldo, January 1984 (has links)
Thesis (M.S.)--University of Michigan, Ann Arbor, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 101-107). Also issued in print.
79

Cavity ringdown spectroscopy of diatomic molecules

Wong, Mo-yee, January 2006 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
80

Clinical study of immediate polishing of Class II, high-copper amalgam restorations in primary molars

Merickel, Melissa M. January 1983 (has links)
Thesis (M.S.)--University of Michigan, Ann Arbor, 1983. / Typescript (photocopy). Includes bibliographical references (leaves 82-91). Also issued in print.

Page generated in 0.0305 seconds