Probing the galactic halo with ROSAT

We discuss the current status of ROSAT shadowing observations designed to search for emission from million degree gas in the halo of the Milky Way galaxy. Preliminary results indicate that million degree halo gas is observed in the 1/4 keV band in some directions, most notably toward the Draco cloud at (l,b) = (92 deg, +38 deg), but that the halo emission is patchy and highly anisotropic. Our current understanding of this halo emission is based on a small handful of observations which have been analyzed to date. Many more observations are currently being analyzed or are scheduled for observation within the next year, and we expect our understanding of this component of the galactic halo to improve dramatically in the near future

Prediction of vortex shedding from circular and noncircular bodies in subsonic flow

An engineering prediction method and associated computer code VTXCLD are presented which predict nose vortex shedding from circular and noncircular bodies in subsonic flow at angles of attack and roll. The axisymmetric body is represented by point sources and doublets, and noncircular cross sections are transformed to a circle by either analytical or numerical conformal transformations. The leeward vortices are modeled by discrete vortices in crossflow planes along the body; thus, the three-dimensional steady flow problem is reduced to a two-dimensional, unsteady, separated flow problem for solution. Comparison of measured and predicted surface pressure distributions, flowfield surveys, and aerodynamic characteristics are presented for bodies with circular and noncircular cross sectional shapes

Prediction of subsonic vortex shedding from forebodies with chines

An engineering prediction method and associated computer code VTXCHN to predict nose vortex shedding from circular and noncircular forebodies with sharp chine edges in subsonic flow at angles of attack and roll are presented. Axisymmetric bodies are represented by point sources and doublets, and noncircular cross sections are transformed to a circle by either analytical or numerical conformal transformations. The lee side vortex wake is modeled by discrete vortices in crossflow planes along the body; thus the three-dimensional steady flow problem is reduced to a two-dimensional, unsteady, separated flow problem for solution. Comparison of measured and predicted surface pressure distributions, flow field surveys, and aerodynamic characteristics are presented for noncircular bodies alone and forebodies with sharp chines

Structural Geology of Eastern Part of Richmond and Western Part of Naomi Park Quadrangles, Utah-Idaho

The mapped area, which includes the eastern part of the Richmond and the western part of the Naomi peak quadrangles, Utah-Idaho, is located in the central part of northern Utah and southeastern Idaho. It is located along the eastern side of Cache Valley and western side of the Bear River Range. Cache Valley is in the Basin and Range province and the Bear River Range is in the Middle Rocky Mountain province. The mapped area is about 8.6 miles long, in the north-south direction, and 7.8 miles long, in the east-west direction. The Mutual Formation of Precambrian age is the oldest stratigraphic unit exposed in the mapped area. It consists of purple and brown quartzite. The Brigham Formation of Early Cambrian age and the Langston Formation of Middle Cambrian age overlie the Mutual in stratigraphic succession. The Salt Lake Formation of Tertiary age unconformably overlies older rocks; it is also faulted against the Mutual Formation. A major landslide of Precambrian, Cambrian, and Ordovician formations is present in the southern part of the mapped area. It is unconformably overlapped by the Salt Lake Formation. The Lake Bonneville Group of late Pleistocene age is present in Cache Valley and overlaps older rocks along the western side of the Bear River Range. The Precambrian and Cambrian stratigraphic units, except for those of the landslide, dip eastward and form the western flank of the Logan Peak syncline. A small disharmonic asymmetrical anticline, in the Langston and Ute Formations of Cambrian age, indicates eastward movement. Two beddingplane faults locally eliminate the basal Naomi Peak Limestone Member of the Langston Formation. A major normal fault, which is nearly vertical, extends along the base of the Bear River Range. Another normal fault, which is probably nearly vertical, parallels the western edge of the foothills. The folding and bedding-plane thrust faulting involve eastward movement and occurred during the Sevier orogeny. This orogeny began during late Jurassic time and extended into the early part of the Tertiary Period. Basin and Range normal faulting began early in the Tertiary Period. The normal faults produced great relief between Cache Valley and the Bear River Range. The landslide surface is thought to have formed as a west-dipping thrust fault. Reversed movement on this fault, due to removal of support on the valley side, produced the major landslide. (58 pages

Wavelet-Based Audio Embedding & Audio/Video Compression

With the decline in military spending, the United States relies heavily on state side support. Communications has never been more important. High-quality audio and video capabilities are a must. Watermarking, traditionally used for copyright protection, is used in a new and exciting way. An efficient wavelet-based watermarking technique embeds audio information into a video signal. Several highly effective compression techniques are applied to compress the resulting audio/video signal in an embedded fashion. This wavelet-based compression algorithm incorporates bit plane coding, first difference coding, and Huffman coding. To demonstrate the potential of this audio embedding audio/video compression system, an audio signal is embedded into a video signal and the combined signal is compressed. Results show that overall compression rates of 15:1 can be achieved. The video signal is reconstructed with a median PSNR of nearly 33dB. Finally, the audio signal is extracted with out error

Investigation of methods for predicting the aerodynamic characteristics of two-lobed parawings

Accurate methods for predicting longitudinal aerodynamic characteristics of two-lobed conical parawings with leading edge boom

Space shuttle nonmetallic materials age life prediction

The chemiluminescence from samples of polybutadiene, Viton, Teflon, Silicone, PL 731 Adhesive, and SP 296 Boron-Epoxy composite was measured at temperatures from 25 to 150 C. Excellent correlations were obtained between chemiluminescence and temperature. These correlations serve to validate accelerated aging tests (at elevated temperatures) designed to predict service life at lower temperatures. In most cases, smooth or linear correlations were obtained between chemiluminescence and physical properties of purified polymer gums, including the tensile strength, viscosity, and loss tangent. The latter is a complex function of certain polymer properties. Data were obtained with far greater ease by the chemiluminescence technique than by the conventional methods of study. The chemiluminescence from the Teflon (Halon) samples was discovered to arise from trace amounts of impurities, which were undetectable by conventional, destructive analysis of the sample

Entomology

The manuscript of the inaugural address of President Winchell, delivered January, 1879, was unfortunately destroyed by fire, along with the manuscript and printed pages of the whole of the bulletin for 1878. After some delay, the most of the other manuscripts have been reproduced, and are here combined with the bulletin for 1879. The paper of Mr. Mendenhall, read at the February meeting, was consumed with other manuscripts, in the fire that destroyed Brackett\u27s Block. A few extracts from it appeared in the Minneapolis Tribune of February 5th, 1879, and to that the Bulletin is indebted for the following

A study of prediction methods for the high angle-of-attack aerodynamics of straight wings and fighter aircraft

Work is described dealing with two areas which are dominated by the nonlinear effects of vortex flows. The first area concerns the stall/spin characteristics of a general aviation wing with a modified leading edge. The second area concerns the high-angle-of-attack characteristics of high performance military aircraft. For each area, the governing phenomena are described as identified with the aid of existing experimental data. Existing analytical methods are reviewed, and the most promising method for each area used to perform some preliminary calculations. Based on these results, the strengths and weaknesses of the methods are defined, and research programs recommended to improve the methods as a result of better understanding of the flow mechanisms involved