11 |
Microgravity survey and 2-D modelling for underground tunnelsNg, Ka-lok, January 2003 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2003. / Also available in print.
|
12 |
Microgravity survey and 2-D modelling for underground tunnels /Ng, Ka-lok, January 2003 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2003.
|
13 |
Gravitational waves from unstable, eccentric and inspiralling compact binary systemsO'Reilly, Rachel Ann January 2002 (has links)
No description available.
|
14 |
Investigation of internal mechanical loss factors of test mass materials for interferometric gravitational wave detectionSneddon, Peter Howard January 2001 (has links)
No description available.
|
15 |
The emergence of gravitational spacesMoolman, Simon 06 February 2015 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. 01 September 2014. / In this thesis I explore the evidence for whether gravity is an emergent phenomenon. I provide a review of black hole thermodynamics and
demonstrate how it provides evidence that gravity is an emergent phe-
nomenon. In addition I provide a review of Jacobson's calculation which
shows how the Einstein eld equations can be interpreted as a thermo-
dynamic equation of state. I then use Jacobson's work and the Seiberg-
Witten map to derive a new gravitational equation of state which shows
what gravity on a non-commutative manifold would look like.
|
16 |
Prediction of offshore gravity from bathymetrySproule, David, Surveying & Spatial Information Systems, Faculty of Engineering, UNSW January 2005 (has links)
The definition of the shape of the geoid is a fundamental objective of geodesy, since it allows for the conversion between orthometric and ellipsoidal height systems. The geoid can be computed from gravity values measured over the surface of the earth, and considerable effort continues to achieve a global coverage of gravity values. One technique that has been very successful in recent years in providing gravity coverage in areas which previously have been too difficult to access is airborne gravimetry. This technique has proved very useful in covering near offshore regions, for example. The coastal regions of Australia are recognised as locations where airborne gravimetry has the potential to fill in missing gravity data. A pilot survey using an airborne gravity meter was undertaken off the north east coast of Australia. In areas that remain unsurveyed it is sometimes useful to fill in the missing gravity data values with predicted gravity values. Previous research has examined the possibility of predicting gravity values from other observed quantities. The best success has been achieved by using the gravity effect calculated from bathymetric information. Often the corresponding isostatic compensation is computed, and the combined bathymetric-isostatic gravity effect is used. However, the type and extent of compensation that exists in any particular region mostly remains unknown. Theoretical considerations indicate that the short wavelength part of the gravity field may be adequately modelled by the gravity effect of the bathymetry alone, without reference to an assumed compensation mechanism. With this in mind, a prediction scheme has been developed which utilises the short wavelength gravity field information implied by the bathymetry, combined with the long wavelength gravity field information from existing observed gravity. This scheme allows the prediction of ???fill-in??? gravity values in areas with limited observed gravity. The prediction technique was used on a test set of data off the east coast of Greenland. The prediction technique was seen to outperform a simple interpolation of gravity values by approximately ten percent. Geoid computations performed with the predicted gravity values indicate that the prediction technique can provide significant improvements in computed geoids.
|
17 |
On the multipole expansion in the computation of gravity anomaliesKim, So Gu 15 April 1971 (has links)
Techniques for computing gravity anomalies by multipole expansions
obtained from surface integrals and volume integrals are derived
together with a vertical line element method. The results are
compared with exact calculation for right rectangular prisms and
right circular cylinders and the effects of block size and separation
between the field point and source body are evaluated.
For sources near field points, the multipole expansion of volume
integrals consistantly yielded more accurate approximations of the
gravity field than either vertical line element or surface integrals.
For a given source, the surface integral method compared to vertical
line elements gives a better approximation of the field. As distance
increases, all three techniques yield accurate gravity values. Improved
estimates of the gravity field can be obtained by subdividing
the source body into small elements and summing the effect of the
elements. The 2nd-order or quadrupole term of the expansions is
dominant for near sources while the 0th-order or monopole term becomes
increasingly important with increasing separation of the source
and field point. / Graduation date: 1971
|
18 |
Interpretation of gravity measurements made in the Cascade Mountains and adjoining basin and range province in central OregonPitts, Gerald Stephen 16 March 1979 (has links)
Graduation date: 1979
|
19 |
Regional gravity of OregonThiruvathukal, John V. 08 November 1967 (has links)
Graduation date: 1968
|
20 |
Cosmology and gravity in the brane worldDent, James Blackman 01 November 2005 (has links)
The cosmology in the Hubble expansion era of the Horava-Witten M-theory
compactified on a Calabi-Yau threefold is studied in the reduction to five-dimensions
where the effects of the Calabi-Yau manifold are summarized by the volume modulus,
and all perturbative potentials are included. Matter on the branes are treated as first
order perturbations of the static vacuum solution, and all equations in the bulk and
all boundary conditions on both end branes are imposed. It is found that for a static
volume modulus and a static fifth dimension, y, one can recover the four dimensional
Robertson-Friedmann-Walker cosmology for relativistic matter on the branes, but not
for non-relativistic matter. For relativistic matter, the Hubble parameter H becomes
independent of y to first order in matter density, and if a consistent solution for nonrelativistic
matter exists it would require H to be y dependent. These results hold also
when an arbitrary number of 5-branes are included in the bulk. The five dimensional
Horava-Witten model is compared with the Randall Sundrum phenomenology with a
scalar field in the bulk where a bulk and brane potential are used so that the vacuum
solutions can be rigorously obtained.(In the Appendix, the difficulty of obtaining
approximate vacuum solutions for other potentials is discussed.) In this case nonrelativistic
matter is accommodated by allowing the distance between the branes to
vary. It is suggested that non-perturbative potentials for the vacuum solution of Horava-Witten theory are needed to remove the inconsistency that non-relativistic
matter creates.
Also considered is the problem of gravitational forces between point particles
on the branes in a Randall-Sundrum (R-S) two brane model with S1/Z2 symmetry.
Matter is assumed to produce a perturbation to the R-S vacuum metric and all the 5D
Einstein equations are solved to linearized order (for arbitrary matter on both branes).
We show that while the gauge condition hi5 = 0, i = 0, 1, 2, 3 can always be achieved
without brane bending, the condition h55 = 0 leads to large brane bending. The static
potential arising from the zero modes and the corrections due to the Kaluza-Klein
(KK) modes are calculated. Gravitational forces on the Planck (y1 = 0) brane recover
Newtonian physics with small KK corrections (in accord with other work). However,
forces on the TeV (y2) brane due to particles on that brane are strongly distorted
by large R-S exponentials, making the model in disagreement with experiment if the
TeV brane is the physical brane.
|
Page generated in 0.2406 seconds