227 research outputs found
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Subsurface Devonian and Mississippian Gas Shale Samples Barnett and Smithwick Shales (Fort Worth Basin) and Woodford and Barnett Shales (Delaware Basin) Core Sampling for Measured Vitrinite Reflectance Determination
This report summarizes activities carried out by the Bureau of Economic Geology (BEG) during Fiscal Year (FY) 2007 for the National Coal Resources Data System State Cooperative Program (NCRDS project). The report represents a departure from those prepared in previous years by providing a collection of Devonian-Mississippian and Mississippian gas-shale samples. Approval for this change in sample type was given by the USGS in March 2008. Samples were collected from whole cores of three wells in Wise and San Saba Counties, Fort Worth Basin, North Texas (Fig. 1), and Pecos County, Delaware Basin, West Texas (Fig. 2) for vitrinite-reflectance (Ro) analysis by the USGS. Other study activities include identification of the sampled shales' precise geographic location and their stratigraphic position.Bureau of Economic Geolog
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Subsurface Gas-Shale Samples Of The Upper Devonian And Lower Mississippian Woodford Shale, Permian Basin, West Texas And Southeastern New Mexico: Core Sampling For Measured Vitrinite-Reflectance (Ro) Determination
This report summarizes activities carried out by the Bureau of Economic Geology (BEG) during fiscal year (FY) 2012 for the National Coal Resources Data System State Cooperative Program (NCRDS project). In a continuation of the sampling strategy for measured vitrinite-reflectance (Ro) determination initiated 4 years ago (Hentz and others, 2009) and conducted during the following three years (Hentz and others, 2010, 2011, 2012), this report provides a collection of oil- and gas-shale samples from the oil- and gas-productive Upper Devonian Woodford Shale of the Permian Basin in Texas and New Mexico (Fig. 1).
In FY2009, 2010, and 2011, we provided samples of the Eagle Ford Shale from the San Marcos Arch and Maverick Basin areas, samples of the deeper Pearsall Formation from the Maverick Basin of the eastern part of Texas, and samples of the Smithwick Shale from the Fort Worth Basin of north Texas, respectively. As specified in our work plan for FY2010 through 2014 (Hentz, 2010), this year we have provided samples of the productive Upper Devonian Woodford Shale in the Permian Basin of West Texas and southeastern New Mexico.Bureau of Economic Geolog
Large-Scale Integration of Nanoelectromechanical Systems for Gas Sensing Applications
We have developed arrays of nanomechanical systems (NEMS) by large-scale integration, comprising thousands of individual nanoresonators with densities of up to 6 million NEMS per square centimeter. The individual NEMS devices are electrically coupled using a combined series-parallel configuration that is extremely robust with respect to lithographical defects and mechanical or electrostatic-discharge damage. Given the large number of connected nanoresonators, the arrays are able to handle extremely high input powers (>1 W per array, corresponding to <1 mW per nanoresonator) without excessive heating or deterioration of resonance response. We demonstrate the utility of integrated NEMS arrays as high-performance chemical vapor sensors, detecting a part-per-billion concentration of a chemical warfare simulant within only a 2 s exposure period
Piezoelectric nanoelectromechanical resonators based on aluminum nitride thin films
We demonstrate piezoelectrically actuated, electrically tunable nanomechanical resonators based on multilayers containing a 100-nm-thin aluminum nitride (AlN) layer. Efficient piezoelectric actuation of very high frequency fundamental flexural modes up to ~80 MHz is demonstrated at room temperature. Thermomechanical fluctuations of AlN cantilevers measured by optical interferometry enable calibration of the transduction responsivity and displacement sensitivities of the resonators. Measurements and analyses show that the 100 nm AlN layer employed has an excellent piezoelectric coefficient, d_(31)=2.4 pm/V. Doubly clamped AlN beams exhibit significant frequency tuning behavior with applied dc voltage
Application of organic and mineral fertilizers increases carbon fractions in two classes of aggregates in an integrated crop-livestock system.
Abstract: Application of organic fertilizers of animal origin can increase organic carbon in the soil and increase its content in macroaggregates. This study aimed to evaluate carbon contents and fractions in two classes of soil aggregates in response to the application of organic and mineral fertilizers in an integrated crop-livestock system. The experiment was established in Concórdia, Santa Catarina State, in a Nitossolo Vermelho Eutroférrico típico, (Rhodic Kandiudox according to the WRB system) (0.00-0.05, 0.05-0.10, and 0.10-0.20 m), in an integrated crop-livestock, with corn and soybean in the summer, black oat and rye in the winter, shepherded by sheep. The design used was randomized blocks, with treatments in factorial design (5 × 3 + 1), with four replications, five sources of fertilizers, three rates and the control with no fertilization. Three organic fertilizers were applied: poultry litter, pig manure and compost; and two minerals fertilizers: M1 (formulated according to the composition of the pig slurry) and M2 (adjusted according to the composition of the poultry litter), combined with three applications rates, corresponding to 75, 100 and 150 % of the recommendation for the crop of interest, based on the element with greater demand. Total organic carbon (TOC), particulate (POC) and mineral-associated organic carbon (MAC) contents were determined in two classes of soil aggregates C1 (8.00 to 4.76 mm) and C2 (4.76 to 2.00 mm), in samples collected in the 2018/2020 crop season. Crop yields were determined in every season. The results were analyzed using analysis of variance to compare sources and polynomial regression analysis for fertilizer rates. The soil has high aggregate stability, even so, the use of organic and mineral fertilizers increased aggregation. The poultry litter organic fertilizer increases aggregation, forming largely aggregates with a size of 8.00-4.76 mm, and increases the contents of total fractions of soil organic carbon, providing the system with a more stabilized carbon. In the 0.00-0.05 m layer, organic fertilizers increased the content of total organic carbon. The stabilized fraction (MAC) showed a higher proportion of total soil organic carbon than particulate organic carbon (POC)
The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study
Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3
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