5,441 research outputs found
Cryogenic Insulation System
This invention relates to reusable, low density, high temperature cryogenic foam insulation systems and the process for their manufacture. A pacing technology for liquid hydrogen fueled, high speed aircraft is the development of a fully reusable, flight weight cryogenic insulation system for propellant tank structures. In the invention cryogenic foam insulation is adhesively bonded to the outer wall of the fuel tank structure. The cryogenic insulation consists of square sheets fabricated from an array of abutting square blocks. Each block consists of a sheet of glass cloth adhesively bonded between two layers of polymethacrylimide foam. Each block is wrapped in a vapor impermeable membrane, such as Kapton(R) aluminum Kapton(R), to provide a vapor barrier. Very beneficial results can be obtained by employing the present invention in conjunction with fibrous insulation and an outer aeroshell, a hot fuselage structure with an internal thermal protection system
Effect of Excess Dietary Crude Protein from Corn Gluten Meal or Soybean Meal on Reproductive Function of Beef Cows Consuming Low Quality Forage
Coproducts of the ethanol industry are a concentrated package of crude protein (CP) which can be fed to beef cows in conjunction with low quality forage to make economical diets that meets nutrient requirements. With this pairing, having excess dietary CP is likely; however the effects of these excessive CP diets on beef cow reproduction have not been made clear. In addition, the effects of excess dietary CP from feedstuffs that differ in rumen degradability are not known. In the present study, we studied the effects of diets containing 150% of metabolizable protein (MP) requirements from a moderately high (corn gluten meal) or low (soybean meal) rumen undegradable protein (RUP) fraction on reproductive function around the time of ovulation. We observed that excess dietary RUP enhanced dominant follicle growth and ovulatory parameters, while excess dietary rumen degradable protein (RDP) improved circulating progesterone concentration post ovulation. Based on these data, source of CP when fed to excess may have differential impacts on reproductive function in mature beef cows. However, the mechanisms by which these physiological alterations occur are unknown at this time. Thus, more research is warranted to elucidate how source and amount of CP, when supplemented in low quality forage-based diets, may influence reproductive function in beef cows
Covariability in the Monthly Mean Convective and Radiative Diurnal Cycles in the Amazon
The diurnal cycle of convective clouds greatly influences the radiative energy balance in convectively active regions of Earth, through both direct presence, and the production of anvil and stratiform clouds. Previous studies show that the frequency and properties of convective clouds can vary on monthly timescales as a result of variability in the monthly mean atmospheric state. Furthermore, the radiative budget in convectively active regions also varies by up to 7 Wm-2 in convectively active regions. These facts suggest that convective clouds connect atmospheric state variability and radiation variability beyond clear sky effects alone. Previous research has identified monthly covariability between the diurnal cycle of CERES-observed top-of-atmosphere radiative fluxes and multiple atmospheric state variables from reanalysis over the Amazon region. ASVs that enhance (reduce) deep convection, such as CAPE (LTS), tend to shift the daily OLR and cloud albedo maxima earlier (later) in the day by 2-3 hr. We first test the analysis method using multiple reanalysis products for both the dry and wet seasons to further investigate the robustness of the preliminary results. We then use CloudSat data as an independent cloud observing system to further evaluate the relationships of cloud properties to variability in radiation and atmospheric states. While CERES can decompose OLR variability into clear sky and cloud effects, it cannot determine what variability in cloud properties lead to variability in the radiative cloud effects. Cloud frequency, cloud top height, and cloud microphysics all contribute to the cloud radiative effect, all of which are observable by CloudSat. In addition, CloudSat can also observe the presence and variability of deep convective cores responsible for the production of anvil clouds. We use these capabilities to determine the covariability of convective cloud properties and the radiative diurnal cycle
The Unprecedented 20162017 Arctic Sea Ice Growth Season: The Crucial Role of Atmospheric Rivers and Longwave Fluxes
The 2016-17 Arctic sea ice growth season (October-March) exhibited the lowest end-of-season sea ice volume and extent of any year since 1979. An analysis of MERRA2 atmospheric reanalysis data and CERES radiative flux data reveals that a record warm and moist Arctic atmosphere supported the reduced sea ice growth through two pathways. First, numerous regional episodes of increased atmospheric temperature and moisture, transported from lower latitudes, increased the cumulative energy input from downwelling longwave surface fluxes. Second, in those same episodes, the efficiency that the atmosphere cooled radiatively to space was reduced, increasing the amount of energy retained in the Arctic atmosphere and reradiated back toward the surface. Overall, the Arctic radiative cooling efficiency shows a decreasing trend since 2000. The results presented highlight the increasing importance of atmospheric forcing on sea ice variability demonstrating that episodic Arctic atmospheric rivers, regions of elevated poleward water vapor transport, and the subsequent surface energy budget response is a critical mechanism actively contributing to the evolution of Arctic sea ice
Effects of Increasing Supplementation of Rumen Undegradable Protein on Plasma Essential Amino Acid Concentrations in Beef Cows Consuming Low Quality Forage
The effects of pairing a low quality forage with increasing metabolizable protein (MP) supplementation from a moderately abundant rumen undegradable protein (RUP) source (corn gluten meal; 62% RUP) on essential plasma amino acid (AA) concentrations were evaluated in a 60-day trial. Non-pregnant, non-lactating cows (n=24) were offered ad libitum access to cornstalks and fed 1 of 3 isocaloric diets (0.48 NEm/lb) and supplemented primarily with corn gluten meal to provide 100% MP requirements (CON), 125% MP requirements (MP125), or 150% MP requirements (MP150). It was observed that increasing concentrations of MP in the diet from a moderately abundant RUP source increased the percent of essential AA, ketogenic AA, branched-chain AA and urea cycle AA in plasma. Also, as a percent of total AA, glycogenic AA were decreased with increased MP supplementation. Therefore, increasing supplementation of MP can the shift essential AA profiles of beef cows when fed with low quality forage
Restorative Recreation: A Medical Humanities Course Relating Nature Prescription, Avocation, and Creation Care to Human and Ecosystem Health
Although there is increasing awareness of the relationships between ecosystem health, access to and interaction with nature, and human wellness, examples of instructional activities to convey these issues in medical education are limited. To address this need, P.C.S. developed a five week elective course for up to twelve students within a medical humanities curriculum. Students discuss themes covered in multi-media assignments, hike at a regional nature center, and write a final reflection essay. Discussion topics include nature-deficit disorder, nature immersion, nature prescription, creation care, social determinants of nature access and environmental health, and restorative recreation as an avocation. Follow-up surveys containing 4-point Likert questions and open-ended queries to determine student perceptions of the course were conducted for the course over two academic years. Analysis of survey responses show students felt the course met learning objectives and offered a positive and constructive learning environment. Thematic analyses identified the nature hike as a course highlight, and course content, opportunities for reflection, and discussion of how nature relates to human health as notable strengths. The course design should be viewed as adaptive to local ecosystems, environmental concerns, and ethical foundations to improve relevance to students at a given institution
Understanding Climate Feedback Contributions to Surface Warming: TOA Versus Surface Perspective
The global-mean surface temperature has warmed by approximately 1.04oC from 1880-2016, primarily driven by the anthropogenic increase of carbon dioxide (CO2). Since Earths temperature is tied to a multitude of physical processes, the increase of CO2 triggers climate feedbacks that modulate the surface warming response. Thus, to understand the surface warming response to increasing CO2, we must also understand how the different climate feedbacks it triggers modify the surface temperature. Most climate feedback studies evaluate radiative feedbacks using a top-of-atmosphere perspective, but a few use a surface perspective instead. The effects of radiative feedbacks on surface temperature should be insensitive to the perspective chosen; past studies, however, have shown conflicting results between the TOA and surface perspectives
Unmasking the Negative Greenhouse Effect over the Antarctic Plateau
A paradoxical negative greenhouse effect has been found over the Antarctic Plateau, indicating that greenhouse gases enhance energy loss to space. Using 13 years of NASA satellite observations, we verify the existence of the negative greenhouse effect and find that the magnitude and sign of the effect varies seasonally and spectrally. A previous explanation attributes this effect solely to stratospheric CO2; however, we surprisingly find that the negative greenhouse effect is predominantly caused by tropospheric water vapor. A recently developed principle-based concept is used to provide a complete account of the Antarctic Plateaus negative greenhouse effect indicating that it is controlled by the vertical variation of temperature and greenhouse gas absorption. Our findings indicate that unique climatological conditions over the Antarctic Plateaua strong surface-based temperature inversion and scarcity of free tropospheric water vaporcause the negative greenhouse effect
"Intelligent Ensemble" Projections of Precipitation and Surface Radiation in Support of Agricultural Climate Change Adaptation
Earth's climate is changing and will continue to change into the foreseeable future. Expected changes in the climatological distribution of precipitation, surface temperature, and surface solar radiation will significantly impact agriculture. Adaptation strategies are, therefore, required to reduce the agricultural impacts of climate change. Climate change projections of precipitation, surface temperature, and surface solar radiation distributions are necessary input for adaption planning studies. These projections are conventionally constructed from an ensemble of climate model simulations (e.g., the Coupled Model Intercomparison Project 5 (CMIP5)) as an equal weighted average, one model one vote. Each climate model, however, represents the array of climate-relevant physical processes with varying degrees of fidelity influencing the projection of individual climate variables differently. Presented here is a new approach, termed the "Intelligent Ensemble, that constructs climate variable projections by weighting each model according to its ability to represent key physical processes, e.g., precipitation probability distribution. This approach provides added value over the equal weighted average method. Physical process metrics applied in the "Intelligent Ensemble" method are created using a combination of NASA and NOAA satellite and surface-based cloud, radiation, temperature, and precipitation data sets. The "Intelligent Ensemble" method is applied to the RCP4.5 and RCP8.5 anthropogenic climate forcing simulations within the CMIP5 archive to develop a set of climate change scenarios for precipitation, temperature, and surface solar radiation in each USDA Farm Resource Region for use in climate change adaptation studies
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