752 research outputs found
Measurements in atmospheric electricity designed to improve launch safety during the Apollo series
Ground test measurements were made during the launches of Apollo 13 and 14 in an effort to better define the electrical characteristics of a large launch vehicle. Of particular concern was the effective electrical length of the vehicle and plume since this parameter markedly affects the likelihood of a lightning stroke being triggered by a launch during disturbed weather conditions. Since no instrumentation could be carried aboard the launch vehicle, the experiments were confined to LF radio noise and electrostatic-field measurements on the ground in the vicinity of the launch pad. The philosophy of the experiment and the instrumentation and layout are described. From the results of the experiment it is concluded that the rocket and exhaust do not produce large-scale shorting of the earth's field out to distances of thousands of feet from the launch pad. There is evidence, however, that the plume does add substantially to the electrical length of the rocket. On this basis, it was recommended that there be no relaxation of launch rules for launches during disturbed weather
The Resonance in the B-P-a Reaction
The yield of alpha particles of range greater than 2 cms. from boron bombarded by protons has been studied as a function of bombarding energy in the range from 100 to 200 ekv, using a thin target, either methyl borate or boron trifluoride at pressures of 1 mm. of Hg. The yield vs. energy curve shows an approximately exponential rise on which is superposed a sharp (half breadth ~ 6 ekv) intense line at 150 ± ekv. There is some indication of a weaker and much broader line at 190 ekv. Number range curves are not yet available, but the appearance of pulses on the oscillograph screen leads us to suppose that the high yield (line) at 150 ekv is due to emission of a homogeneous long-range group
Renal Stone Risk During Space Flight: Assessment and Countermeasure Validation
NASA has focused its future on exploration class missions including the goal of returning to the moon and landing on Mars. With these objectives, humans will experience an extended exposure to the harsh environment of microgravity and the associated negative effects on all the physiological systems of the body. Exposure to microgravity affects human physiology and results in changes to the urinary chemical composition during and after space flight. These changes are associated with an increased risk of renal stone formation. The development of a renal stone would have health consequences for the crewmember and negatively impact the success of the mission. As of January 2007, 15 known symptomatic medical events consistent with urinary calculi have been experienced by 13 U.S. astronauts and Russian cosmonauts. Previous results from both MIR and Shuttle missions have demonstrated an increased risk for renal stone formation. These data have shown decreased urine volume, urinary pH and citrate levels and increased urinary calcium. Citrate, an important urinary inhibitor of calcium-containing renal stones binds with calcium in the urine, thereby reducing the amount of calcium available to form calcium oxalate stones. Urinary citrate also prevents calcium oxalate crystals from aggregating into larger crystals and into renal stones. In addition, citrate makes the urine less acidic which inhibits the development of uric acid stones. Potassium citrate supplementation has been successfully used to treat patients who have formed renal stones. The evaluation of potassium citrate as a countermeasure has been performed during the ISS Expeditions 3-6, 8, 11-13 and is currently in progress during the ISS Expedition 14 mission. Together with the assessment of stone risk and the evaluation of a countermeasure, this investigation provides an educational opportunity to all crewmembers. Individual urinary biochemical profiles are generated and the risk of stone formation is estimated. Increasing fluid intake is recommended to all crewmembers. These results can be used to lower the risk for stone formation through lifestyle, diet changes or therapeutic administration to minimize the risk for stone development. With human presence in microgravity a continuing presence and exploration class missions being planned, maintaining the health and welfare of all crewmembers is critical to the exploration of space
Sports mega-events – three sites of contemporary political contestation
This article discusses the contemporary politics of sports mega-events, involving the Olympic Games and Fédération Internationale de Football Association (FIFA) Men’s Football World Cup Finals as well as other lower ‘order’ sports megas, taking two main forms: the promotional and the protest. There is a politics in, and a politics of, sports mega-events. The former focuses on the internal politics of the organizing bodies, such as the International Olympic Committee and FIFA. This form of politics has been written about elsewhere, and hence, there is no detailed discussion in this article about it. Instead this article offers a brief discussion of the range and number of sports mega-events since 2000, an assessment of the contemporary politics of sports mega-events, a focus on three main sites of political contestation – rights, legacy and labour, and finally, it offers conclusions about research into the politics of sports mega-events
Mapping Planetary Volcanic Deposits: Identifying Vents and Distingushing between Effects of Eruption Conditions and Local Lava Storage and Release on Flow Field Morphology
Terrestrial geologic mapping techniques are regularly used for "photogeologic" mapping of other planets, but these approaches are complicated by the diverse type, areal coverage, and spatial resolution of available data sets. When available, spatially-limited in-situ human and/or robotic surface observations can sometimes introduce a level of detail that is difficult to integrate with regional or global interpretations. To assess best practices for utilizing observations acquired from orbit and on the surface, our team conducted a comparative study of geologic mapping and interpretation techniques. We compared maps generated for the same area in the San Francisco Volcanic Field (SFVF) in northern Arizona using 1) data collected for reconnaissance before and during the 2010 Desert Research And Technology Studies campaign, and 2) during a traditional, terrestrial field geology study. The operations, related results, and direct mapping comparisons are discussed in companion LPSC abstracts [1-3]. Here we present new geologic interpretations for a volcanic cone and related lava flows as derived from all approaches involved in this study. Mapping results indicate a need for caution when interpreting past eruption conditions on other planetary surfaces from orbital data alone
Comparing and Reconciling Traditional Field and Photogeologic Mapping Techniques: Lessons from the San Francisco Volcanic Field, Arizona
Cartographic products and - specifically - geologic maps provide critical assistance for establishing physical and temporal frameworks of planetary surfaces. The technical methods that result in the creation of geologic maps vary depending on how observations are made as well as the overall intent of the final products [1-3]. These methods tend to follow a common linear work flow, including the identification and delineation of spatially and temporally discrete materials (units), the documentation of their primary (emplacement) and secondary (erosional) characteristics, analysis of the relative and absolute age relationships between these materials, and the collation of observations and interpretations into an objective map product. The "objectivity" of a map is critical cross comparison with overlapping maps and topical studies as well as its relevance to scientific posterity. However, the "accuracy" and "correctness" of a geologic map is very subject to debate. This can be evidenced by comparison of existing geologic maps at various scales, particularly those compiled through field- and remote-based mapped efforts. Our study focuses on comparing the fidelity of (1) "Apollo-style" geologic investigations, where typically non-geologist crew members follow static traverse routes established through pre-mission planning, and (2) "traditional" field-based investigations, where geologists are given free rein to observe without preplanned routes. This abstract summarizes the regional geology wherein our study was conducted, presents the geologic map created from traditional field mapping techniques, and offers basic insights into how geologic maps created from different tactics can be reconciled in support of exploratory missions. Additional abstracts [4-6] from this study discuss various exploration and science results of these efforts
Mapping Planetary Volcanic Deposits: Identifying Vents and Distinguishing between Effects of Eruption Conditions and Local Storage and Release on Flow Field Morphology
Terrestrial geologic mapping techniques are regularly used for "photogeologic" mapping of other planets, but these approaches are complicated by the diverse type, areal coverage, and spatial resolution of available data sets. When available, spatially-limited in-situ human and/or robotic surface observations can sometimes introduce a level of detail that is difficult to integrate with regional or global interpretations. To assess best practices for utilizing observations acquired from orbit and on the surface, our team conducted a comparative study of geologic mapping and interpretation techniques. We compared maps generated for the same area in the San Francisco Volcanic Field (SFVF) in northern Arizona using 1) data collected for reconnaissance before and during the 2010 Desert Research And Technology Studies campaign, and 2) during a traditional, terrestrial field geology study. The operations, related results, and direct mapping comparisons are discussed in companion LPSC abstracts. Here we present new geologic interpretations for a volcanic cone and related lava flows as derived from all approaches involved in this study. Mapping results indicate a need for caution when interpreting past eruption conditions on other planetary surfaces from orbital data alone
Impact of Alternative Energy Prices, Tenure Arrangements and Irrigation Technologies on a Typical Texas High Plains Farm
Irrigation is a major contributing factor in crop production on the Texas High Plains. It is responsible for greatly increasing crop production and farm income for the region. Two factors, a declining groundwater supply and increasing production costs, are of primary concern because they impact on farm operations and producer economic viability.
A recursive linear programming model for a typical Texas High Plains irrigated farm was developed to evaluate expected impact of price changes, tenure and new technology. The model includes a Fortran sub-routine that adjusts irrigation factors each year based on the linear programming solution of the previous year. After calculating new pumping energy requirements, well yield, and pumping lift, the Fortran component updates the linear programming model. This procedure continues automatically to the end of a specified planning period or to economic exhaustion of the groundwater, whichever occurs first.
Static applications of the model, in a deep water situation, showed that a natural gas price increase from 2.20 per thousand cubic feet (mcf) would result in reductions in irrigation levels. Irrigation was terminated when the price of natural gas reached about 3.60 per mcf) before short-run adjustments in farm organization began to occur. Under furrow irrigation, irrigation was terminated when the natural gas price reached 0.25 per mcf (from 995 million with 50 percent improved efficiency.
Limitations in borrowing can substantially reduce annual net returns. This analysis suggests that the farmer can economically justify very high costs of borrowing rather than a limitation of funds available for operating expenses
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