5,412 research outputs found
Fabrication of cooled, graphite-lined structures
Improved method of fabricating cooled graphite-lined thrust chamber has been developed. Layer of nickel is electrodeposited onto outer surface of machined and contoured graphite liner. Coolant passages are machined into nickel layer, filled with wax, outer shell electroformed over this, and wax removed. Tests in flox/methane rocket engine were completely successful
Experimental validation of a landing-dynamics computer program for legged spacecraft landers
Validation of a landing-dynamics computer program has been accomplished by comparing analytical data with data from a limited experimental program. Agreement obtained established the subject landing-dynamics computer program as a reliable design tool for legged spacecraft landers
A study of the cornering forces generated by aircraft tires on a tilted, free-swiveling nose gear
An experimental investigation was conducted to study the effect of various parameters on the cornering forces produced by a rolling aircraft tire installed on a tilted, free-swiveling nose gear. The parameters studied included tilt angle, trial, tire inflation pressure, rake angle, vertical load, and whether or not a twin tire configuration corotates. These parameters were evaluated by measuring the cornering force produced by an aircraft tire installed on the nose gear of a modified vehicle as it was towed slowly. Cornering force coefficient increased with increasing tilt angle. Increasing trial or rake angle decreased the magnitude of the cornering force coefficient. Tire inflation pressure had no effect on the cornering force coefficient. Increasing vertical load decreased the cornering force coefficient. When the tires of a twin tire system rotated independently, the cornering force coefficients were the same as those for the single-tire configuration. When the twin tire system was made to corotate, however, the cornering force coefficients increased significantly
Technology requirements for an orbiting fuel depot: A necessary element of a space infrastructure
Advanced planning within NASA has identified several bold space exploration initiatives. The successful implementation of these missions will require a supporting space infrastructure which would include a fuel depot, an orbiting facility to store, transfer and process large quantities of cryogenic fluids. In order to adequately plan the technology development programs required to enable the construction and operation of a fuel depot, a multidisciplinary workshop was convened to assess critical technologies and their state of maturity. Since technology requirements depend strongly on the depot design assumptions, several depot concepts are presented with their effect on criticality ratings. Over 70 depot-related technology areas are addressed
Variations in the richness of children's interests and experiences in literature.
Thesis (Ed.M.)--Boston Universit
The First Lunar Ranging Constraints on Gravity Sector SME Parameters
We present the first constraints on pure-gravity sector Standard-Model
Extension (SME) parameters using Lunar Laser Ranging (LLR). LLR measures the
round trip travel time of light between the Earth and the Moon. With 34+ years
of LLR data, we have constrained six independent linear combinations of SME
parameters at the level of to . There is no evidence for
Lorentz violation in the LLR dataset.Comment: 7 pages, presented at the Fourth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, August 200
Fabrication of large tungsten structures by chemical vapor deposition
Process is accomplished by reducing tungsten hexafluoride with hydrogen. Metallic tungsten of essentially 100 percent purity and density is produced and built up as dense deposit on heated mandrel assembly. Process variations are building up, sealing or bonding refractory metals at temperatures below transition temperatures of base metal substrates
An evaluation of the IDEEA™ activity monitor for estimating energy expenditure
Peer reviewedPublisher PD
Beneficial effects of exercise: shifting the focus from body weight to other markers of health
Background: Exercise is widely promoted as a method of weight management, while the other health benefits are often ignored. The purpose of this study was to examine whether exercise-induced improvements in health are influenced by changes in body weight. Methods: Fifty-eight sedentary overweight/obese men and women (BMI 31.8 (SD 4.5) kg/m2) participated in a 12-week supervised aerobic exercise intervention (70% heart rate max, five times a week, 500 kcal per session). Body composition, anthropometric parameters, aerobic capacity, blood pressure and acute psychological response to exercise were measured at weeks 0 and 12. Results: The mean reduction in body weight was −3.3 (3.63) kg (p<0.01). However, 26 of the 58 participants failed to attain the predicted weight loss estimated from individuals’ exercise-induced energy expenditure. Their mean weight loss was only −0.9 (1.8) kg (p<0.01). Despite attaining a lower-than-predicted weight reduction, these individuals experienced significant increases in aerobic capacity (6.3 (6.0) ml/kg/min; p<0.01), and a decreased systolic (−6.00 (11.5) mm Hg; p<0.05) and diastolic blood pressure (−3.9 (5.8) mm Hg; p<0.01), waist circumference (−3.7 (2.7) cm; p<0.01) and resting heart rate (−4.8 (8.9) bpm, p<0.001). In addition, these individuals experienced an acute exercise-induced increase in positive mood. Conclusions: These data demonstrate that significant and meaningful health benefits can be achieved even in the presence of lower-than-expected exercise-induced weight loss. A less successful reduction in body weight does not undermine the beneficial effects of aerobic exercise. From a public health perspective, exercise should be encouraged and the emphasis on weight loss reduced
A Bachelor\u27s Thesis in Architecture
In the year of 1975, the ultimate student population of the University of New Mexico shall have been reached; 25,000 students will be in daily attendance. The central campus will be a beehive of activity. The Master Plans which have been put forth in an attempt at directing the growth of UNM have not taken into consideration the impact of this growth upon the surrounding city
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