3,334 research outputs found

    Reclamation Laws and Costs of Strip Mined Land in North Dakota

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    Coal is becoming more important as a source of energy. There are16 billion tons of economically surface minable coal in North Dakota underlying 700,000 acres. The state has a comprehensive reclamation law; mining cannot be undertaken unless reclamation can be successfully completed. This report presents an overview of reclamation legislation passed in North Dakota, and estimates of reclamation costs are given.Resource /Energy Economics and Policy,

    Nonresident Hunters in North Dakota: Characteristics, Expenditures, Harvest

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    This study was initiated when a need for data on nonresident hunter expenditures and activities was identified in a departmental research effort considering alternative uses of wetlands. Also, nonresident hunting license sales are an important source of revenue for the North Dakota State Game and Fish Department. In 1976, 7.5 percent of the hunters in the state were nonresidents, but nonresident license sales accounted for 27 percent of all state hunting license revenue. The data in this report fill a void that existed in estimating the economic significance of all hunting in North Dakota since a similar study dealing with resident hunters was conducted in the department in 1973.Resource /Energy Economics and Policy,

    Economic Impact of Flooding on Agricultural Production in Northeast Central North Dakota

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    The Devils Lake Basin is a closed basin in which a number of damaging floods have been recorded in recent decades. Flooding occurs in the spring as a result of snowmelt and in the summer as a result of severe summer rainstorms. The main flood problem in the Basin is damage to agricultural land and crops. This report presents a procedure for estimating flood damages in the Basin and preliminary flood damage estimates are given. Also included are selected statistics on wetland and drainage in the Devils Lake Basin.Production Economics, Resource /Energy Economics and Policy,

    Fault motions at the Baldwin Hills Reservoir site

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    A distinction is made between the damaging potential of rapid fault motions associated with earthquakes and those having a relatively slow creep type motion. Information is given on nonseismic movements that have been occurring on faults passing through the Baldwin Hills Reservoir during the past 10 years. The relationship between those faults and the Inglewood fault system is described, and correlations are presented with local elevation changes, horizontal ground movements, and seismic activity. Comparisons are made with similar slow fault motions occurring at other places in California, and attention is drawn to the potential damaging effects of such movements

    The Environment for Application Software Integration and Execution (EASIE), version 1.0. Volume 2: Program integration guide

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    The Environment for Application Software Integration and Execution, EASIE, provides a methodology and a set of software utility programs to ease the task of coordinating engineering design and analysis codes. EASIE was designed to meet the needs of conceptual design engineers that face the task of integrating many stand-alone engineering analysis programs. Using EASIE, programs are integrated through a relational data base management system. In volume 2, the use of a SYSTEM LIBRARY PROCESSOR is used to construct a DATA DICTIONARY describing all relations defined in the data base, and a TEMPLATE LIBRARY. A TEMPLATE is a description of all subsets of relations (including conditional selection criteria and sorting specifications) to be accessed as input or output for a given application. Together, these form the SYSTEM LIBRARY which is used to automatically produce the data base schema, FORTRAN subroutines to retrieve/store data from/to the data base, and instructions to a generic REVIEWER program providing review/modification of data for a given template. Automation of these functions eliminates much of the tedious, error prone work required by the usual approach to data base integration

    Mechanical properties of several neat polymer matrix materials and unidirectional carbon fiber-reinforced composites

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    The mechanical and physical properties of three neat matrix materials, i.e., PEEK (polyetheretherketone) thermoplastic, Hexcel F155 rubber-toughened epoxy and Hercules 8551-7 rubber-toughened epoxy, were experimentally determined. Twelve unidirectional carbon fiber composites, incorporating matrix materials characterized in this or earlier studies (with one exception; the PISO(sub 2)-TPI matrix itself was not characterized), were also tested. These composite systems included AS4/2220-1, AS4/2220-3, T500/R914, IM6/HX1504, T300/4901A (MDA), T700/4901A (MDA), T300/4901B (MPDA), T700/4901B (MPDA), APC2 (AS4/PEEK, ICI), APC2 (AS4/PEEK, Langley Research Center), AS4/8551-7, and AS4/PISO(sub 2)-TPI. For the neat matrix materials, the tensile, shear, fracture toughness, coefficient of thermal expansion, and coefficient of moisture expansion properties were measured as a function of both temperature and moisture content. For the unidirectional composites, axial and transverse tensile, longitudinal shear, coefficient of thermal expansion, and coefficient of moisture expansion properties were determined, at room temperature and 100 C

    Static tensile and tensile creep testing of four boron nitride coated ceramic fibers at elevated temperatures

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    Six types of uncoated ceramic fibers were static tensile and tensile creep tested at various elevated temperatures. Three types of boron nitride coated fibers were also tested. Room temperature static tensile tests were initially performed on all fibers, at gage lengths of 1, 2, and 4 inches, to determine the magnitude of end effects from the gripping system used. Tests at one elevated temperature, at gage lengths of 8 and 10 inches, were also conducted, to determine end effects at elevated temperatures. Fiber cross sectional shapes and areas were determined using scanning electron microscopy. Creep testing was typically performed for 4 hours, in an air atmosphere

    Exploratory Chandra Observations of the Three Highest Redshift Quasars Known

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    We report on exploratory Chandra observations of the three highest redshift quasars known (z = 5.82, 5.99, and 6.28), all found in the Sloan Digital Sky Survey. These data, combined with a previous XMM-Newton observation of a z = 5.74 quasar, form a complete set of color-selected, z > 5.7 quasars. X-ray emission is detected from all of the quasars at levels that indicate that the X-ray to optical flux ratios of z ~ 6 optically selected quasars are similar to those of lower redshift quasars. The observations demonstrate that it will be feasible to obtain quality X-ray spectra of z ~ 6 quasars with current and future X-ray missions.Comment: 15 pages, ApJL, in press; small revisions to address referee Comment

    Evaluation of Joint Space Width and Narrowing After Isolated Partial Medial Meniscectomy for Degenerative Medial Meniscus Tears

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    BACKGROUND: Few studies have evaluated the effect of existing articular cartilage damage and sex on joint space measurements after isolated degenerative medial meniscus tears. PURPOSE: To determine what factors affected joint space width and narrowing in patients after removal of isolated degenerative medial meniscus tears. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 62 patients (15 women and 47 men) with all ligaments intact, no previous surgery to either knee, and an isolated degenerative medial meniscus tear removed in 1 knee were examined. The mean age at examination was 58.2 years at a mean follow-up of 9.4 years (range, 4-20 years). Subjective results were obtained with the International Knee Documentation Committee (IKDC) knee survey. Radiographs were taken using 45° weightbearing posteroanterior views. Midpoint and perceived minimum joint space width of the medial and lateral compartments of both knees were measured to the nearest 0.1 mm by 2 observers at different times, and they were blinded as to the previous measurements (Pearson intra- and interclass correlations, >0.93). Joint space narrowing was found by calculating the difference in joint space width between knees. Percentage of normal joint space loss was calculated by dividing joint space narrowing by the joint space width in the contralateral knee. Other factors considered were patient sex and Outerbridge grading of articular cartilage. RESULTS: Women had a mean 1.5 mm less normal joint space width than men in the involved and noninvolved knees (P 50% of the normal joint space as measured in the noninjured knee (P = .016). The mean IKDC total score was 66.1 points for women, which was statistically significantly lower than the mean of 82.7 points for men (P < .01). CONCLUSION: Patients undergoing partial medial meniscectomy have greater joint space narrowing and lower subjective scores after surgery if they also have existing Outerbridge grade 3-4 damage. Women have less normal joint space than men, and more women than men experience >50% joint space narrowing after surgery
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