553 research outputs found

    Wing shape optimization for maximum cross-country speed, with mathematical programming

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    A computer program was developed to calculate numerically the speed and circling polars of an aircraft when the lift and drag characteristics of the wing airfoils are known. The planform of the wing is described by variables which are optimized so that the cross-country speed of the glider is maximum for the particular type of thermal model. Two thermal models are compared and shown that with a greater wing area than now normally used the performance can be increased

    Final Science Reports of the US Experiments Flown on the Russian Biosatellite Cosmos 2229

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    Cosmos 2229 was launched on December 29, 1992, containing a biological payload including two young male rhesus monkeys, insects, amphibians, and cell cultures. The biosatellite was launched from the Plesetsk Cosmodrome in Russia for a mission duration of 11.5 days. The major research objectives were: (1) Study of adaptive response mechanisms of mammals during flight; and (2) Study of physiological mechanisms underlying vestibular, motor system and brain function in primates during early and later adaptation phases. American scientists and their Russian collaborators conducted 11 experiments on this mission which included extensive preflight and postflight studies with rhesus monkeys. Biosamples and data were subsequently transferred to the United States. The U.S. responsibilities for this flight included the development of experiment protocols, the fabrication of some flight instrumentation and experiment-specific ground-based hardware, the conducting of preflight and postflight testing and the analysis of biospecimens and data for the U.S. experiments. A description of the Cosmos 2229 mission is presented in this report including preflight, on-orbit and postflight activities. The flight and ground-based bioinstrumentation which was developed by the U.S. and Russia is also described, along with the associated preflight testing ot the U.S. hardware. Final Science Reports for the experiments are also included

    Vigor, vitality and seed dormancy of Avena sativa cultivars in a long-term experiment

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    Vigor, vitality and seed dormancy of 14 Finnish cultivars of Avena sativa in room temperature were studied in a 22-year laboratory experiment. These parameters were studied by measuring morphological and physical characteristics of seeds and by basic germination and enzymatic tests 1, 4, 6, 11, 16, 21 and 22 years after seed harvesting in 1989. Methylene blue, Congo red and 2,3,5-triphenyltetrazolium chloride (TZ) tests were used to estimate seed quality and changes in vitality over time. Seed vitality clearly decreased in all cultivars during the experiment. The mean vitality declined from 96.3% (one year after harvest) to zero at the end. Vitality according to the TZ test was higher than indicated by the basic germination test. The mean vitality loss was 4.6% per year, but there were clear differences between cultivars. The decrease in vitality correlated with loss in seed weight. Clear signs of deepening dormancy were observed. Seed age is an important factor infl uencing vitality and dormancy. Vitality loss of seeds led to deep dormancy. The appearance, water uptake and imbibition of the seeds remained normal until the end. Ageing, vitality loss and dormancy are concluded to be expressions of genes. It is possible that in the future electronic simulation methods will be developed that will enable accurate estimation of oat seed quality without laboratory tests

    Nitrogen Fertilization and Harvest Management Improve Forage and Crude Protein Content in Crabgrass

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    Crabgrass (Digitaria spp.) is an annual summer grass that can provide high-quality forage, but optimal management strategies are unclear. Our objective was to compare the yield and quality of crabgrass (Mojo and Quick-N-Big) under different nitrogen rates and harvest management. The experimental design was a randomized complete block with five treatments and three replications for each crabgrass variety, totaling fifteen experimental units for both Mojo and Quick-N-Big, in adjacent sites. Treatments were nitrogen rates (0, 100, and 200 lb N/acre) and harvest management (cut once or twice per year) for two growing seasons (2020 and 2021). Total forage accumulation (TFA) increased with nitrogen fertilization for both cultivars. Mojo had the highest TFA in the first year (7000 lb DM/a/yr) while Quick-N-Big TFA was the highest in the second year (7635 lb DM/a/yr). The highest crude protein (CP) content was obtained with the highest N dose, ranging from 10.5 to 13% for both cultivars. Based on these results, N fertilization and harvest management can contribute to improving forage yield and crude protein of crabgrass varieties during the growing season in forage systems

    How Colors Influence Numbers: Photon Statistics of Parametric Downconversion

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    Parametric downconversion (PDC) is a technique of ubiquitous experimental significance in the production of non-classical, photon-number correlated twin beams. Standard theory of PDC as a two-mode squeezing process predicts and homodyne measurements observe a thermal photon number distribution per beam. Recent experiments have obtained conflicting distributions. In this paper, we explain the observation by an a-priori theoretical model solely based on directly accessible physical quantities. We compare our predictions with experimental data and find excellent agreement.Comment: 4 {pages, figures

    Impact of Fertility and Mowing on Crabgrass Quantity and Quality for Hay Production in Southeast Kansas

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    A crabgrass variety trial comparing Quick-N-Big and Mojo crabgrasses was conducted in 2021 at the K-State Experiment Station outside of Columbus, KS. The trial evaluated forage quantity and quality under different fertilization and harvest management practices

    Fertilization Management to Improve Stockpiled Tall Fescue in the Fall

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    In 2019 and 2021, a tall fescue fertility study was conducted at the K-State Experiment Station near Columbus, KS. The purpose of the study was to determine the effect of summer fertilization on forage quality and quantity in stockpiled fescue. If a producer can stockpile high-quality forage for late fall and early winter grazing, protein supplementation may not be necessary for fall calving cows

    Bermudagrass Under Different Fertility and Harvest Management Practices

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    A second year of a bermudagrass fertility study was conducted at the K-State Research and Experiment Station outside of Columbus, KS, in 2021. The purpose of the study was to simulate forage producers’ practices of managing bermudagrass and determine how each practice affected forage production and quality
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