Theory of a Higher Order Phase Transition: Superconducting Transition in BKBO

We describe here the properties expected of a higher (with emphasis on the order fourth) order phase transition. The order is identified in the sense first noted by Ehrenfest, namely in terms of the temperature dependence of the ordered state free energy near the phase boundary. We have derived an equation for the phase boundary in terms of the discontinuities in thermodynamic observables, developed a Ginzburg-Landau free energy and studied the thermodynamic and magnetic properties. We also discuss the current status of experiments on $Ba_{0.6}K_{0.4}BiO_3$ and other $BiO_3$ based superconductors, the expectations for parameters and examine alternative explanations of the experimental results.Comment: 18 pages, no figure

Combining a New 3-D Seismic S-Wave Propagation Analysis for Remote Fracture Detection With a Robust Subsurface Microfracture-Based Verification Technique

Fractures within the producing reservoirs at McElroy Field could not be studied with the industry-provided 3C3D seismic data used as a cost-sharing contribution in this study. The signal-to-noise character of the converted-SV data across the targeted reservoirs in these contributed data was not adequate for interpreting azimuth-dependent data effects. After illustrating the low signal quality of the converted-SV data at McElroy Field, the seismic portion of this report abandons the McElroy study site and defers to 3C3D seismic data acquired across a different fractured carbonate reservoir system to illustrate how 3C3D seismic data can provide useful information about fracture systems. Using these latter data, we illustrate how fast-S and slow-S data effects can be analyzed in the prestack domain to recognize fracture azimuth, and then demonstrate how fast-S and slow-S data volumes can be analyzed in the poststack domain to estimate fracture intensity. In the geologic portion of the report, we analyze published regional stress data near McElroy Field and numerous formation multi-imager (FMI) logs acquired across McElroy to develop possible fracture models for the McElroy system. Regional stress data imply a fracture orientation different from the orientations observed in most of the FMI logs. This report culminates Phase 2 of the study, ''Combining a New 3-D Seismic S-Wave Propagation Analysis for Remote Fracture Detection with a Robust Subsurface Microfracture-Based Verification Technique''. Phase 3 will not be initiated because wells were to be drilled in Phase 3 of the project to verify the validity of fracture-orientation maps and fracture-intensity maps produced in Phase 2. Such maps cannot be made across McElroy Field because of the limitations of the available 3C3D seismic data at the depth level of the reservoir target

The use of neutron scattering experiments for studying molecular hydrogen in amorphous hydrogenated carbon

The presence of molecular hydrogen in a-C:H has been demonstrated by a series of neutron scattering experiments. Neutron diffraction gives a peak in the pair correlation function corresponding to the H-H bond distance. Inelastic neutron scattering experiments have shown peaks consistent with the H-2 rotation and stretch, and revealed details of the hydrogen environment

Inelastic neutron scattering of molecular hydrogen in amorphous hydrogenated carbon

We have, by use of inelastic neutron scattering, detected the presence of molecular hydrogen in amorphous hydrogenated car-bon. We have found the hydrogen to be in a high-pressure, asymmetric environment formed by the compressive stresses in the a-C: H films. On comparing two samples, we have also found that the sample with higher molecular hydrogen concentration has a lower total hydrogen composition. This is caused by a higher network density, trapping the molecular hydrogen during network growth