740 research outputs found
Development of an integrated heat pipe-thermal storage system for a solar receiver
The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube
Gamma Ray and Neutron Spectrometer for the Lunar Resource Mapper
One of the early Space Exploration Initiatives will be a lunar orbiter to map the elemental composition of the Moon. This mission will support further lunar exploration and habitation and will provide a valuable dataset for understanding lunar geological processes. The proposed payload will consist of the gamma ray and neutron spectrometers which are discussed, an x ray fluorescence imager, and possibly one or two other instruments
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Membrane heat pipe development for space radiator applications
A self-deploying membrane heat pipe (SMHP) is being designed and fabricated to operate in an in-cabin experiment aboard a STS flight. The heat pipe comprises a mylar membrane with a woven fabric arterial wick and R-11 as the working fluid. Preliminary results indicate that this SMHP design will successfully expand and retract in response to an applied heat load; the retraction force is provided by a constant force spring
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Establishing low-power operating limits for liquid metal heat pipes
Liquid metal heat pipes operated at power throughputs well below their design point for long durations may fail as a result of the working fluid migrating to a cold region within the pipe, freezing there, and hot returning to the evaporator section. Eventually sufficient working fluid inventory may be lost to the cold region to cause a local dry-out condition in the evaporator. A joint experimental and analytical effort between the Air Force Phillips Laboratory and Los Alamos National Laboratory is underway to investigate the phenomena. Experiments include both high temperature liquid metal and low temperature organic heat pipes. To date, a low temperature working fluid has been selected and its performance in a heat pipe validated. Additionally, a low-temperature heat pipe has been fabricated and is presently being tested
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Joint Assessment of Renewable Energy and Water Desalination Research Center (REWDC) Program Capabilities and Facilities In Radioactive Waste Management
The primary goal of this visit was to perform a joint assessment of the Renewable Energy and Water Desalination Center's (REWDC) program in radioactive waste management. The visit represented the fourth technical and scientific interaction with Libya under the DOE/NNSA Sister Laboratory Arrangement. Specific topics addressed during the visit focused on Action Sheet P-05-5, ''Radioactive Waste Management''. The Team, comprised of Mo Bissani (Team Lead), Robert Fischer, Scott Kidd, and Jim Merrigan, consulted with REWDC management and staff. The team collected information, discussed particulars of the technical collaboration and toured the Tajura facility. The tour included the waste treatment facility, waste storage/disposal facility, research reactor facility, hot cells and analytical labs. The assessment team conducted the first phase of Task A for Action Sheet 5, which involved a joint assessment of the Radioactive Waste Management Program. The assessment included review of the facilities dedicated to the management of radioactive waste at the Tourja site, the waste management practices, proposed projects for the facility and potential impacts on waste generation and management
Effect of Strength on Velocity and Power During Back Squat Exercise in Resistance-Trained Men and Women
The purpose was to examine load-velocity and load-power relationships of back squat in resistance-trained men (n = 20, 21.3 ± 1.4 years, 183.0 ± 8.0 cm, 82.6 ± 8.0 kg, 11.5 ± 5.0% total body fat) and women (n = 18; 20.0 ± 1.0 years; 166.5 ± 6.9 cm; 63.9 ± 7.9 kg, 20.3 ± 5.0% body fat). Body composition testing was performed followed by determination of back squat 1 repetition maximum (1RM). After at least 72 hours of recovery, subjects returned to the laboratory and completed 2 repetitions at each of 7 separate loads (30, 40, 50, 60, 70, 80, and 90% 1RM) in a random order. During each repetition, peak and average velocity and power were quantified using a commercially available linear position transducer. Men produced higher absolute peak and average power and velocity at all loads. When power output was normalized for body mass, significant differences remained. However, when normalizing for strength, no significant differences were observed between sexes. Furthermore, when subjects were subdivided into strong and weak groups, those above the median 1RM produced higher peak power, but only at loads greater than 60% 1RM. It was concluded that differences between men and women may be a result of strength rather than biological sex. Furthermore, training for maximal strength may be an appropriate method to augment maximal power output in those athletes who exhibit low levels of strength
Simplifying External Load Data in NCAA Division-I Men\u27s Basketball Competitions: A Principal Component Analysis
The primary purpose was to simplify external load data obtained during Division-I (DI) basketball competitions via principal component analysis (PCA). A secondary purpose was to determine if the PCA results were sensitive to load demands of different positional groups (POS). Data comprised 229 observations obtained from 10 men\u27s basketball athletes participating in NCAA DI competitions. Each athlete donned an inertial measurement unit that was affixed to the same location on their shorts prior to competition. The PCA revealed two factors that possessed eigenvalues \u3e1.0 and explained 81.42% of the total variance. The first factor comprised total decelerations (totDEC, 0.94), average speed (avgSPD, 0.90), total accelerations (totACC, 0.85), total mechanical load (totMECH, 0.84), and total jump load (totJUMP, 0.78). Maximum speed (maxSPD, 0.94) was the lone contributor to the second factor. Based on the PCA, external load variables were included in a multinomial logistic regression that predicted POS (Overall model, p \u3c 0.0001; AUCcenters = 0.93, AUCguards = 0.88, AUCforwards = 0.80), but only maxSPD, totDEC, totJUMP, and totMECH were significant contributors to the model\u27s success (p \u3c 0.0001 for each). Even with the high significance, the model still had some issues differentiating between guards and forwards, as in-game demands often overlap between the two positions. Nevertheless, the PCA was effective at simplifying a large external load dataset collected on NCAA DI men\u27s basketball athletes. These data revealed that maxSPD, totDEC, totJUMP, and totMECH were the most sensitive to positional differences during competitions. To best characterize competition demands, such variables may be used to individualize training and recovery regimens most effectively
Susceptibility of hamsters to clostridium difficile isolates of differing toxinotype
Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD), which caused ~21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative), M68 (toxinotype VIII) and BI-7 (toxinotype III). The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c.) with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT) are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial and toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression
Renewable Energy
This chapter presents an in-depth examination of major renewable energy technologies, including their installed capacity and energy supply in 2009 , the current state of market and technology development, their economic and financial feasibility in 2009 and in the near future,
as well as major issues they may face relative to their sustainability
or implementation. Renewable energy sources have been important for humankind since the beginning of civilization. For centuries, biomass has been used for heating, cooking, steam generation, and power production;
solar energy has been used for heating and drying; geothermal energy has been used for hot water supplies; hydropower, for movement;
and wind energy, for pumping and irrigation. For many decades renewable energy sources have also been used to produce electricity or
other modern energy carriers
EC04-183 Chickpea Production in the High Plains
Chickpea (Cicer arietinum L.) is an annual grainlegume or “pulse crop” that is used extensively for human consumption. The seed of this plant, when dried, is commonly used in soup. Its primary use in the United States is for salad bars, while in the Middle East and India it is more frequently cooked and blended with rice dishes. Major chickpea producers include India, Pakistan, Mexico, Turkey, Canada, and Australia. Chickpea makes up more than 20 percent of world pulse production, behind dry bean and pea. Currently, the United States imports more than 80 percent of its domestic chickpea needs. Since the 1980s, chickpea production has increased rapidly in the northwestern United States. Meanwhile, due to agronomic, processing, and marketing constraints, production in the High Plains has been sporadic and often short-lived. During the past few years, the development of new varieties and the potential for chickpea production under dryland and limited irrigation conditions has generated renewed interest among High Plains producers. With this in mind, the purpose of this publication is to provide information to enhance the potential for successful chickpea production
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