The signed loop approach to the Ising model: foundations and critical point

The signed loop method is a beautiful way to rigorously study the two-dimensional Ising model with no external field. In this paper, we explore the foundations of the method, including details that have so far been neglected or overlooked in the literature. We demonstrate how the method can be applied to the Ising model on the square lattice to derive explicit formal expressions for the free energy density and two-point functions in terms of sums over loops, valid all the way up to the self-dual point. As a corollary, it follows that the self-dual point is critical both for the behaviour of the free energy density, and for the decay of the two-point functions.Comment: 38 pages, 7 figures, with an improved Introduction. The final publication is available at link.springer.co

Spectral Reflectance Measurements of Sulfides at the Planetary Emissivity Laboratory — Analogs for Hollow-Forming Material on Mercury?

We present spectral reflectance measurements at visible and near-infrared wavelengths of fresh and heated samples of MnS, CaS, and MgS, as well as elemental sulfur. We infer that sulfides display a diagnostic feature at or near 0.6 µm

Recording Equipment for Internal Friction Measurements

An apparatus was developed for recording internal friction data in such a manner as to circumvent many of the laborious and time-consuming observations and calculations usually associated with these measurements. An optical lever is used and the passage of the beam across the scale is detected by photoconductive cells. The cells are strategically located so that, when their signals are fed through a multichannel switching circuit to the pens of an operation recorder, a plot of the logarithm of the vibrational amplitude versus the number of cycles is recorded on the chart. From the definitmon of the logarithmic decrement, ( delta ), it can be shown that the slope of this curve is - delta . The apparatus is inexpensive and requires a minimum of maintenance. It has been used for accurate determinations of values of delta from below 0.0001 up to 0.3. (auth

Investigation and evaluation of geopressured-geothermal wells. Final report: Beulah Simon No. 2 Well, Vermilion Parish, Louisiana. Volume II. Analytical data

A compilation of the test data and computer printouts of the various reservoir calculations for the reentry of the Beulah Simon No. 2 well are presented. The data include: bottomhole and surface pressure data, geothermal field test data, pressure buildup model analysis, recombination of produced brine, chemical analyses of brine and gas, and chemical analyses performed by Champion Chemicals, Inc. (MHR

Investigation and evaluation of geopressured-geothermal wells. Fairfax Foster Sutter No. 2 well, St. Mary Parish, Louisiana. Volume I. Completion and testing. Final report

The Fairfax Foster Sutter No. 2 well, located in the East Franklin area of St. Mary Parish, Louisiana, is the first successful test of a geopressured-geothermal aquifer under the Well-of-Opportunity program. The section tested was the MA-6 sand of lower Miocene age which has produced large quantities of gas from the adjacent but structurally separated Garden City field. In the subject well the observed temperature was 270{sup 0}F (132{sup 0}C) and the measured gradient was 0.77 psi/ft. The gross sand thickness was 270 feet, the net sand thickness 190 feet, and the tested interval 58 net feet. The temperatures and pressures encountered approached the limits of the surface-recording bottomhole pressure gauge and particularly the single-conductor cables on which the gauges were run. The objectives of the tests were all accomplished, and data were obtained which will contribute to the overall assessment of the geopressured-geothermal resource of the Upper Gulf of Mexico basin. In general, the gas solubility (22.8 scf/bbl) was as expected for the temperature, pressure, and salinity of the brine. The produced water was more saline than expected (160,000 mg/l). The high concentrations of dissolved solids, coupled with the evolution of CO{sub 2} from these waters during production, created a scaling problem in the tubular goods and surface equipment that will have to be addressed in future tests

Investigation and evaluation of geopressured-geothermal wells. Final report: Beulah Simon No. 2 Well, Vermilion Parish, Louisiana. Volume I. Completion and testing

Geopressured-geothermal (Geo{sup 2}) test operations were conducted at the Beulah Simon No. 2 well site during the period from September through December 1979. The well provided the second geopressured-geothermal test to be completed under the DOE-Gruy Well of Opportunity program. The completion in a geopressured aquifer of Oligocene age at approximately 14,700 feet and the testing of hot salt water from this zone were accomplished without significant difficulty. Some problems were encountered with the wireline and wireline high-pressure lubricator associated with the running of bottomhole instruments. The objectives of the project were all accomplished, and good test data were obtained on the flow rates of gas and water. The gas content was 24 standard cubic feet per stock tank barrel of water. The disposal well accepted the full wellhead stream at temperatures as high as 255{sup 0}F (124{sup 0}C). Over the 10-day flow period the hot brine did not appear to adversely affect the clay minerals in the disposal aquifer. A conclusion from this operation is that presently available wirelines and pressure lubricators are not adaptable for use with uninhibited well fluids under flowing conditions. In addition, this test demonstrated that injection of scale inhibitor down the annulus eliminated scale buildup within the flow string and surface facilities. (MHR

Investigation and evaluation of geopressured-geothermal wells. Final report, Tenneco Fee N No. 1 Well Terrebonne Paris, Louisiana

The reservoir conditions that led to the choice of this well as the fifth well of opportunity are described as well as the attempts to complete the well for high-volume brine production. Individual opinions concerning underlying and conributing causes for the liner failure which aborted the completion attempt are included. (MHR