2,531 research outputs found

    Subscale Flight Testing for Aircraft Loss of Control: Accomplishments and Future Directions

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    Subscale flight-testing provides a means to validate both dynamic models and mitigation technologies in the high-risk flight conditions associated with aircraft loss of control. The Airborne Subscale Transport Aircraft Research (AirSTAR) facility was designed to be a flexible and efficient research facility to address this type of flight-testing. Over the last several years (2009-2011) it has been used to perform 58 research flights with an unmanned, remotely-piloted, dynamically-scaled airplane. This paper will present an overview of the facility and its architecture and summarize the experimental data collected. All flights to date have been conducted within visual range of a safety observer. Current plans for the facility include expanding the test volume to altitudes and distances well beyond visual range. The architecture and instrumentation changes associated with this upgrade will also be presented

    Late Summer Planted Oat-Brassica Forage Quality Changes during Winter Grazing

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    Oat, radish, and turnip samples were taken on pivots being grazed from November through January in Clay Center, Nebraska. The objective was to determine how the quality changed throughout the winter. The forage was observed to be high-quality (highly digestibility with moderate CP content). Digestibility did decline over this period but minimal changes in CP content were observed. From early November to early January, the digestibility of oats appeared to decline more (10% unit decline) than turnip and radish leaves (5% unit decrease). However, digestibility (67% IVOMD) and CP content (15%) of oats in early January were still as high as a good quality grass hay. Brassica (radish and turnip) leaves were more similar to a concentrate (81–83% IVOMD and 23–26% CP) even in January. Thus, even though the forage changed color from green to brown after hard freezes, the forage still had good feed value in January

    Make Research Data Public? -- Not Always so Simple: A Dialogue for Statisticians and Science Editors

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    Putting data into the public domain is not the same thing as making those data accessible for intelligent analysis. A distinguished group of editors and experts who were already engaged in one way or another with the issues inherent in making research data public came together with statisticians to initiate a dialogue about policies and practicalities of requiring published research to be accompanied by publication of the research data. This dialogue carried beyond the broad issues of the advisability, the intellectual integrity, the scientific exigencies to the relevance of these issues to statistics as a discipline and the relevance of statistics, from inference to modeling to data exploration, to science and social science policies on these issues.Comment: Published in at http://dx.doi.org/10.1214/10-STS320 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Synchronous vs. asynchronous dynamics of diffusion-controlled reactions

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    An analytical method based on the classical ruin problem is developed to compute the mean reaction time between two walkers undergoing a generalized random walk on a 1d lattice. At each time step, either both walkers diffuse simultaneously with probability pp (synchronous event) or one of them diffuses while the other remains immobile with complementary probability (asynchronous event). Reaction takes place through same site occupation or position exchange. We study the influence of the degree of synchronicity pp of the walkers and the lattice size NN on the global reaction's efficiency. For odd NN, the purely synchronous case (p=1p=1) is always the most effective one, while for even NN, the encounter time is minimized by a combination of synchronous and asynchronous events. This new parity effect is fully confirmed by Monte Carlo simulations on 1d lattices as well as for 2d and 3d lattices. In contrast, the 1d continuum approximation valid for sufficiently large lattices predicts a monotonic increase of the efficiency as a function of pp. The relevance of the model for several research areas is briefly discussed.Comment: 21 pages (including 12 figures and 4 tables), uses revtex4.cls, accepted for publication in Physica

    2018 Establishing groundwater Nitrate / Nitrite levels In Hamilton, Montana & local areaMarch

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    We propose to collect emergent groundwater around Hamilton, using standardized collection methods that include quality and control samples with analysis performed at a certified drinking water testing laboratory (Energy Labs). Nitrate background in natural groundwater systems should contain less that\u27s 1 mg/L nitrates (U.S. Geological Survey) but in our aquifer, nitrates/nitrites should be less than 0.25 mg/L based on previous sampling. We will map the locations of the samples and use local hydrology data to help determine the source and flow direction of the groundwater. Routine testing and reporting of groundwater quality in our community will help protect our health and the economy of our river. Groundwater in sand and gravel aquifers from shallow wells supplies all the Hamilton area drinking water. The aquifers receive recharge from streams and ditches flowing in from he sides of the valley and the shallow aquifers discharge to the Bitterroot River and to ditches that flow past the West and north edge of Hamilton. we plan to collect about a dozen samples in an arc around the down gradient edge of Hamilton from these groundwater discharges. Nitrates are tasteless and odorless, and are often the first sign of deterioration of groundwater quality. Nitrates are a health threat because they can cause blue baby syndrome and may function as initiators of human carcinogenesis. Nitrates are also an environmental threat because they cause eutrophication damage to surface water aquatic environments in the Bitterroot River. High densities of private septic systems, and large acreages that receive fertilizer or that support farm animals are located up gradient to the south and eats of Hamilton. these are probable sources of pollution to shallow groundwater

    Analytical maximum likelihood estimation of stellar magnetic fields

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    The polarised spectrum of stellar radiation encodes valuable information on the conditions of stellar atmospheres and the magnetic fields that permeate them. In this paper, we give explicit expressions to estimate the magnetic field vector and its associated error from the observed Stokes parameters. We study the solar case where specific intensities are observed and then the stellar case, where we receive the polarised flux. In this second case, we concentrate on the explicit expression for the case of a slow rotator with a dipolar magnetic field geometry. Moreover, we also give explicit formulae to retrieve the magnetic field vector from the LSD profiles without assuming mean values for the LSD artificial spectral line. The formulae have been obtained assuming that the spectral lines can be described in the weak field regime and using a maximum likelihood approach. The errors are recovered by means of the hermitian matrix. The bias of the estimators are analysed in depth.Comment: accepted for publication in MNRA

    Effect of Backgrounding System on Steer Performance and Carcass Characteristics

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    The impact of 3 backgrounding systems: grazing corn residue with distillers grains supplementation at 0.86% BW/d, grazing an oats-brassica forage, or feeding a grower ration in a drylot on finishing performance and carcass characteristics were evaluated. Backgrounding phase gains were greatest for steers fed a grower ration in the drylot (3.58 lb/d), intermediate for steers grazing oats-brassica forage and then fed the grower ration for short period (2.65 lb/d), and least for steers grazing corn residue while supplemented distillers grains and then fed the grower ration for short period (2.22 lb/d). These backgrounding treatment differences did not affect ADG during the finishing period (3.73 lb/d). However, the 2 grazing treatments had greater DMI resulting in poorer F:G. Overall, these backgrounding systems did not affect carcass quality. Increased finishing phase cost for the 2 grazing treatments due to poorer F:G, can be off set by less input cost during backgrounding, but ultimately the cost effectiveness is dependent on the production resources and scenarios of each individual producer

    Perceptions of Crop Consultants and Crop Producers on Grazing Corn Residue in Nebraska

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    We conducted a survey to evaluate factors influencing consultant recommendations on grazing and producer grazing practices in Nebraska. Producers who did not graze cited soil compaction, inconvenience (lack of watering and fencing), and lack of access to livestock as major reasons for not grazing. Producers who allowed grazing and consultants who recommended grazing were more likely than those who did not favor grazing to perceive that grazing increased subsequent grain yields. Most consultants and producers reported making decisions on the basis of their personal observations. Findings from the survey can be used for enhanced Extension dissemination and research activities regarding grazing of residues
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