4,127 research outputs found

    Discovery of Pulsed X-ray Emission from the SMC Transient RX J0117.6-7330

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    We report on the detection of pulsed, broad-band, X-ray emission from the transient source RX J0117.6-7330. The pulse period of 22 seconds is detected by the ROSAT/PSPC instrument in a 1992 Sep 30 - Oct 2 observation and by the CGRO/BATSE instrument during the same epoch. Hard X-ray pulsations are detectable by BATSE for approximately 100 days surrounding the ROSAT observation (1992 Aug 28 - Dec 8). The total directly measured X-ray luminosity during the ROSAT observation is 1.0E38 (d/60 kpc)^2 ergs s-1. The pulse frequency increases rapidly during the outburst, with a peak spin-up rate of 1.2E-10 Hz s-1 and a total frequency change 1.8%. The pulsed percentage is 11.3% from 0.1-2.5 keV, increasing to at least 78% in the 20-70 keV band. These results establish RX J0117.6-7330 as a transient Be binary system.Comment: 17 pages, Latex, aasms, accepted for publication in ApJ Letter

    Estimating ventilation rates of animal houses through CO2 balance

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    Citation: Liu, Z., Powers, W., & Harmon, J. D. (2016). Estimating ventilation rates of animal houses through CO2 balance. Transactions of the Asabe, 59(1), 321-328. doi:10.13031/trans.59.10235The CO2 production rates from various animal species were measured as well as the ventilation rates (VR) in environmental rooms at Michigan State University over the course of 15 studies that considered dietary strategies to alter air emissions, including two dairy cow studies, four steer studies, two swine studies, one Turkey study, four laying hen studies, and two broiler chicken studies. The objectives of this article are to summarize the baseline data on CO2 production from various animal species and determine uncertainties of the CO2 balance approach for estimating VR of animal houses by evaluating the model performance in these studies. In the poultry (broiler, laying hen, and Turkey) and dairy studies, the CO2 production rates per heat production of animals or respiratory quotient (RQ) showed a decreasing trend with increasing animal age or days in milk (DIM). Higher variation in CO2 production rates per heat production of animals were observed in young broiler chicken (<3 weeks) and Turkeys (<10 weeks) and in the dairy cow studies. The modeled and measured CO2 production rates were generally comparable with each other for each species, and the standard deviation of model residuals was about 20% to 30% of the average measured CO2 production rate for each species except dairy cows. By only including data in which the differences between exhaust and inlet CO2 concentrations were larger than 50 ppm, the standard deviations of model residuals were less than 32% of the average measured VR in the broiler, laying hen, swine, and steer studies. Based on the results, when using the CO2 balance approach to estimate VR for broiler, laying hen, swine, and steer operations, a minimum of ten replicate measurements is required to achieve a margin of error less than 20% in modeled VR with 95% confidence. © 2016 American Society of Agricultural and Biological Engineers

    Influences on the organizational implementation of sustainability: an integrative model

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    Multiple forces in the 21st century have propelled businesses into confronting conditions that challenge their own and the world’s sustainability. This paper illuminates the factors influencing companies to implement sustainability practices. It validates an integrative model of the effects that external influences, foundational organization enablers, decision drivers, and inhibitors had on both sustainability implementation and organizational performance. Using data from a worldwide survey of 1514 managers, we showed how external forces for sustainability and support from organizational leaders to create an enabling foundation are likely to translate into decision priorities, implementation of sustainability practices, and perceived performance improvement. We also showed the considerable power of internal inhibiting forces and outlined how they may be overcome. The results point to the steps leaders can take to achieve their environmental, social, and financial goals, as well as to further streams of inquiry

    CO2 Balance and Estimation of Ventilation Rates in Animal Studies

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    The CO 2 emissions were measured in environmental rooms in 15 animal operation studies, including studies of dairy cow, steer, swine, turkey, laying hen and broiler. The objectives of this paper are to summarize CO 2 emission data in these 15 studies;, to investigate the possible diet effect; and to evaluate the performance of the CO 2 balance approach to estimate ventilation rate (VR) of animal houses. Lower CO 2 emissions were observed from steers fed diets containing 60% DDGs as compared to that from steers fed the control diets (0% DDGs). Significant differences in CO2 emissions were observed among different studies for each species of broiler, laying hen, swine, and steer, which could be the result of different management practices, different stages of production, or different weather conditions. In 10 out of the 15 studies, the measured CO2 emissions were significantly larger than the estimated CO2 productions, which could represent the corresponding amount of CO2 generation that was not accounted in the metabolic CO 2 production as well as uncertainties in measurements of CO2 emissions. The overall R2 was 0.97 when treating each of the 15 studies as one data point. The relative differences between measured and estimated VR were in the range of 6.3% to 20.5%. Uncertainties in estimated VR in dairy cow studies were relatively large because the relatively large variations in measured CO2 emissions in these studies were not well represented by the relatively constant estimated CO2 production values
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