924 research outputs found

    Shock wave compression of iron-silicate garnet

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    Shock wave Hugoniot data have been obtained for almandine-garnet of composition (Fe_(0.79), Mg_(0.14), Ca_(0.04), Mn_(0.03)) Al_2Si_3O_(12) to pressures of >650 kb. The Hugoniot data indicate the onset of a high-pressure phase at 195 ± 20 kb. Equation-of-state systematics and crystal chemical data (stemming largely from analog compounds) suggest that the high-pressure phase occurs in an ‘ilmenitelike’ structure with an initial density of 4.44 ± 0.04 g/cm^3. This value represents an increase of about 6% over the initial garnet density of 4.180 ± 0.005 g/cm^3. The adiabatic bulk modulus K_0^s and its first pressure derivative (∂K^s/∂P)_T were calculated for the high-pressure phase and found to be 3.19 ± 0.39 Mb and 2.6 ± 0.7, respectively. The major source of probable error in these values results from the indicated uncertainty in the initial density of the high-pressure phase. These results strongly suggest that upper mantle minerals are likely to occur in the ilmenite structure over a substantial part of the lower mantle

    Tomato culture in Missouri

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    Caption title.Digitized 2006 AES MoU

    Reduction of blade-vortex interaction noise using higher harmonic pitch control

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    An acoustics test using an aeroelastically scaled rotor was conducted to examine the effectiveness of higher harmonic blade pitch control for the reduction of impulsive blade-vortex interaction (BVI) noise. A four-bladed, 110 in. diameter, articulated rotor model was tested in a heavy gas (Freon-12) medium in Langley's Transonic Dynamics Tunnel. Noise and vibration measurements were made for a range of matched flight conditions, where prescribed (open-loop) higher harmonic pitch was superimposed on the normal (baseline) collective and cyclic trim pitch. For the inflow-microphone noise measurements, advantage was taken of the reverberance in the hard walled tunnel by using a sound power determination approach. Initial findings from on-line data processing for three of the test microphones are reported for a 4/rev (4P) collective pitch control for a range of input amplitudes and phases. By comparing these results to corresponding baseline (no control) conditions, significant noise reductions (4 to 5 dB) were found for low-speed descent conditions, where helicopter BVI noise is most intense. For other rotor flight conditions, the overall noise was found to increase. All cases show increased vibration levels

    Irrigated Alfalfa Variety Performance, 2011-2014; North Logan, Utah

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    Alfalfa is the most important crop in Utah, both in terms of acreage and revenue. Although often overlooked, one of the most critical decisions made in alfalfa production is determining which variety to plant. This fact sheet summarizes dry matter (DM) yields of alfalfa varieties during 4 years at the Utah Agricultural Experiment Station Greenville Farm in North Logan (Cache Co.)

    On-stack replacement, distilled

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    On-stack replacement (OSR) is essential technology for adaptive optimization, allowing changes to code actively executing in a managed runtime. The engineering aspects of OSR are well-known among VM architects, with several implementations available to date. However, OSR is yet to be explored as a general means to transfer execution between related program versions, which can pave the road to unprecedented applications that stretch beyond VMs. We aim at filling this gap with a constructive and provably correct OSR framework, allowing a class of general-purpose transformation functions to yield a special-purpose replacement. We describe and evaluate an implementation of our technique in LLVM. As a novel application of OSR, we present a feasibility study on debugging of optimized code, showing how our techniques can be used to fix variables holding incorrect values at breakpoints due to optimizations

    Nitrogen Fertilization and Glyphosate-Resistant Alfalfa Termination Method Effects on First-Year Silage Corn

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    Tillage type/timing and herbicide application date may change the amount and timing of N mineralization, altering fertilizer N needs for first-year corn (Zea mays L.) following glyphosate [N-(phosphonomethyl)glycine]-resistant (GR) alfalfa (Medicago sativa L.). Studies were conducted in 2012 and 2013 in Utah. Yield, quality, and economic return of silage corn as affected by five tillage type/timings (fall conventional till, spring conventional till, fall strip-till, spring strip-till, and no-till), three herbicide application dates for alfalfa termination (fall, spring, and in-crop), and four N rates (0, 56, 112, and 224 kg ha−1) were evaluated. Silage corn yield and quality following GR alfalfa was economically optimized without N fertilization regardless of tillage type/timing and herbicide application date. Thus, N from decomposing alfalfa can provide the full N requirement of first-year silage corn following GR alfalfa. Estimated animal milk production ha−1 of silage corn was greatest and similar for all herbicide application dates with conventional tillage and spring herbicide application with strip-till and no-till (26–38 Mg milk ha−1), whereas an in-crop herbicide application with strip-till and no-till resulted in the lowest estimated milk production (21–29 Mg milk ha−1). Increased economic return for the in-crop herbicide date by including economics from harvesting the first alfalfa cutting before planting corn mostly offset the reduced economic return of the lower silage corn yield. Therefore, an application of 2,4-D (2,4-dichlorophenoxyacetic acid) and dicamba (3,6-dichloro-2-methoxybenzoic acid) in the fall, spring, or in-crop to control GR alfalfa are good economic options for conventional tillage, strip-till, and no-till systems

    Solar-Terrestrial Coupling Evidenced by Periodic Behavior in Geomagnetic Indexes and the Infrared Energy Budget of the Thermosphere

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    We examine time series of the daily global power (W) radiated by carbon dioxide (at 15 microns) and by nitric oxide (at 5.3 microns) from the Earth s thermosphere between 100 km and 200 km altitude. Also examined is a time series of the daily absorbed solar ultraviolet power in the same altitude region in the wavelength span 0 to 175 nm. The infrared data are derived from the SABER instrument and the solar data are derived from the SEE instrument, both on the NASA TIMED satellite. The time series cover nearly 5 years from 2002 through 2006. The infrared and solar time series exhibit a decrease in radiated and absorbed power consistent with the declining phase of the current 11-year solar cycle. The infrared time series also exhibits high frequency variations that are not evident in the solar power time series. Spectral analysis shows a statistically significant 9-day periodicity in the infrared data but not in the solar data. A very strong 9-day periodicity is also found to exist in the time series of daily A(sub p) and K(sub p) geomagnetic indexes. These 9-day periodicities are linked to the recurrence of coronal holes on the Sun. These results demonstrate a direct coupling between the upper atmosphere of the Sun and the infrared energy budget of the thermosphere

    Multiple locus VNTR analysis highlights that geographical clustering and distribution of Dichelobacter nodosus, the causal agent of footrot in sheep, correlates with inter-country movements

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    Dichelobacter nodosus is a Gram-negative, anaerobic bacterium and the causal agent of footrot in sheep. Multiple locus variable number tandem repeat (VNTR) analysis (MLVA) is a portable technique that involves the identification and enumeration of polymorphic tandem repeats across the genome. The aims of this study were to develop an MLVA scheme for D. nodosus suitable for use as a molecular typing tool, and to apply it to a global collection of isolates. Seventy-seven isolates selected from regions with a long history of footrot (GB, Australia) and regions where footrot has recently been reported (India, Scandinavia), were characterised. From an initial 61 potential VNTR regions, four loci were identified as usable and in combination had the attributes required of a typing method for use in bacterial epidemiology: high discriminatory power (D > 0.95), typeability and reproducibility. Results from the analysis indicate that D. nodosus appears to have evolved via recombinational exchanges and clonal diversification. This has resulted in some clonal complexes that contain isolates from multiple countries and continents; and others that contain isolates from a single geographic location (country or region). The distribution of alleles between countries matches historical accounts of sheep movements, suggesting that the MLVA technique is sufficiently specific and sensitive for an epidemiological investigation of the global distribution of D. nodosus
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