Use of magnetic sails for advanced exploration missions

The magnetic sail, or magsail, is a field effect device which interacts with the ambient solar wind or interstellar medium over a considerable volume of space to generate drag and lift forces. Two theories describing the method of thrust generation are analyzed and data results are presented. The techniques for maintaining superconductor temperatures in interplanetary space are analyzed and low risk options presented. Comparisons are presented showing mission performance differences between currently proposed spacecraft using chemical and electric propulsion systems, and a Magsail propelled spacecraft capable of generating an average thrust of 250 Newtons at a radius of one A.U. The magsail also provides unique capabilities for interstellar missions, in that at relativistic speeds the magnetic field would ionize and deflect the interstellar medium producing a large drag force. This would make it an ideal brake for decelerating a spacecraft from relativistic speeds and then maneuvering within the target star system

A mean-removed variation of weighted universal vector quantization for image coding

Weighted universal vector quantization uses traditional codeword design techniques to design locally optimal multi-codebook systems. Application of this technique to a sequence of medical images produces a 10.3 dB improvement over standard full search vector quantization followed by entropy coding at the cost of increased complexity. In this proposed variation each codebook in the system is given a mean or 'prediction' value which is subtracted from all supervectors that map to the given codebook. The chosen codebook's codewords are then used to encode the resulting residuals. Application of the mean-removed system to the medical data set achieves up to 0.5 dB improvement at no rate expense

Coal Resources of the Springfield Coal Bed in Western Kentucky

Historically, the Springfield (Western Kentucky No. 9) coal bed has been the leading source of production in the Western Kentucky Coal Field. The Springfield coal is known for its lateral continuity in terms of both thickness and coal quality. It is estimated to have the largest original and remaining resource in the Western Kentucky Coal Field (Greb and others, 1992)

Portable Computers Used in Respiratory Care Charting

journal articleBiomedical Informatic

Microwave spectra of C2H4⋅H2O and isotopomers

The rotational spectrum of the ethylene‐water complex has been reexamined using Fourier‐transform microwave spectroscopy. Several new transitions were observed in the spectrum of the normal isotopic species. All the transitions were split into doublets with a 3:1 relative intensity ratio. Additionally, the spectra of C2H4⋅HDO, C2H4⋅D2O, C2H4⋅H218O, C2H4⋅H217O, cis‐CHD=CHD⋅H2O, trans‐CHD=CHD⋅H2O, 1,1‐CD2=CH2⋅H2O, and CHD=CH2⋅H2O were measured. Splitting patterns and relative intensities of the tunneling doublets of the isotopomers are consistent with a high‐barrier tunneling pathway which exchanges the two water hydrogen atoms. A second, low‐barrier internal rotation of the water about the hydrogen bond is proposed to explain anomalous dipole moment and 17O nuclear quadrupole coupling results.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70059/2/JCPSA6-98-2-791-1.pd

Computer Charting: An Evaluation of a Respiratory Care Computer System

journal articleBiomedical Informatic

Coal Availability in Western Kentucky

Fourteen quadrangles in five separate areas of the Western Kentucky Coal Field were studied to determine what factors affect the availability of coal for mining. Each study area consisted of at least two adjacent 7.5-minute quadrangles in order to account for the geologic variability across broad distances in western Kentucky, and determine how this variability affects availability. Areas both north and south of the Rough Creek Fault System were selected to measure the effect of different geologic, structural, and overburden settings on coal availability. The study emphasized the coals occurring stratigraphically between the Springfield and the Baker. About 90 percent of western Kentucky coal resources is associated with only six beds, and one bed, the Springfield (W. Ky. No. 9), constitutes 25 percent of the entire estimate. Seventy percent of the resource is greater than 56 in. thick. Most mining in the Western Kentucky Coal Field is currently by underground methods; only 25 percent is by surface mining. A geographic information system (GIS) was used to estimate tonnages. Point data were obtained from over 5,000 drill-hole and geophysical-log descriptions, and included coal thickness, parting thickness, elevation, and stratigraphic position. Outcrops were digitized from U.S. Geological Survey (USGS) 7.5-minute geologic quadrangle maps, and land-use restrictions from USGS 7.5-minute topographic quadrangle maps. Mined-out areas were obtained from the Kentucky Department of Mines and Minerals, and locations of oil and gas wells from the Kentucky Geological Survey. A digital elevation model was obtained from the U.S. Geological Survey. Land-use restrictions can apply to both surface and deep mining. Technological restrictions in this study generally apply only to deep mining, and include barriers around existing mines, mining within 40 vertical feet of a seam, active oil and gas wells, coal too thin for current underground mining methods (less than 28 in.), and small mine blocks. Many technological restrictions in western Kentucky could be overcome if the relatively low profit margins in the region increased. Tonnage estimates for each bed are reported by categories of coal thickness, overburden thickness, and reliability of the estimate. Thickness categories used in this study are 14 to 28 in., 28 to 42 in., and greater than 42. in. Overburden categories are surface-mineable, deep-mineable, and too deep to mine with current technology. Reliability categories, based on distance from coal-thickness measurements, are measured (within % mi of a data point), indicated (between % and % mi), inferred (between % and 3 mi), and hypothetical (beyond 3 mi). Total original resources for the assessed coals in the 14 studied quadrangles are estimated at 5.55 billion tons (BT). Almost half this total is accounted for by the Springfield coal, and nearly a quarter by the Baker. About 77 percent of the coal is considered deep-mineable. A total of 1.084 BT, or 20 percent of he original resource, has been mined out or lost to mining. Thus, 4 BT, or 80 percent of original resources, remain. The average amount of restricted coal is 26 percent of original resources, and 88 percent of this restricted amount is by technological factors. The most important technological restriction was coal too thin to mine. Small interburden thickness between two mineable seams is a key factor in some areas; other locally important factors are mine barriers and small mine blocks. The average availability of coal in the 14 studied quadrangles is 54 percent. The results by quadrangle range from 9 to 91 percent, which confirms the necessity of studying larger areas. Deep-mineable coal between 28 and 42 in. thick and surface-mineable coal between 14 and 28 in. thick is considered available, but uneconomic. The uneconomic resources account for 14 percent of the original resource, leaving 40 percent of the coal that is both available and economic

Analytical two-center integrals over Slater geminal functions

We present analytical formulas for the calculation of the two-center two-electron integrals in the basis of Slater geminals and products of Slater orbitals. Our derivation starts with establishing a inhomogeneous fourth-order ordinary differential equation that is obeyed by the master integral, the simplest integral with inverse powers of all interparticle distances. To solve this equation it was necessary to introduce a new family of special functions which are defined through their series expansions around regular singular points of the differential equation. To increase the power of the interparticle distances under the sign of the integral we developed a family of open-ended recursion relations. A handful of special cases of the integrals is also analysed with some remarks on simplifications that occur. Additionally, we present some numerical examples of the master integral that validate the usefulness and correctness of the key equations derived in this paper. In particular, we compare our results with the calculations based on the series expansion of the exp(-\gamma r12) term in the master integral.Comment: 28 pages, 0 figures, 7 table

Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets

The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed