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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Ways of increasing muscular activity by means of isometric muscular exertion

The effect of isometric muscular exertion on the human body was investigated by having subjects perform basic movements in a sitting position in the conventional manner with additional muscle tension at 50% maximum force and at maximum force. The pulse, arterial pressure, skin temperature, respiratory rate, minute respiratory volume and electrical activity of the muscles involved were all measured. Performance of the exercises with maximum muscular exertion for 20 sec and without movement resulted in the greatest shifts in these indices; in the conventional manner substantial changes did not occur; and with isometric muscular exertion with 50% maximum force with and without movement, optimal functional shifts resulted. The latter is recommended for use in industrial exercises for the prevention of hypodynamia. Ten exercises are suggested.

Kovalik, A. V.↗
NASA NTRS1981

Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

Noting that protein synthesis declines in the gastrocnemius 6 hr after immobilization, the study sought to detect an increase of protein synthesis when the limb was freed, and to examine the effects of exercise on the rate of increase. Rats were used as subjects, with their hind legs in plaster of Paris in plantar flexion to eliminate strain on the gastrocnemius. Periods of immobilization were varied and samples of blood from the muscle were taken to track protein synthesis rates for different groups in immobilization and exercise regimens (running and weightlifting). Synthesis rates declined 3.6% during time in the cast, then increased 6.3%/day after the casts were removed. Both running and weightlifting were found to increase the fractional rate of protein formation in the gastrocnemius muscle when compared with contralateral muscles that were not exercised and were used as controls, suggesting that the mechanism controlling protein synthesis in skeletal muscles is rapidly responsive to changes in muscular contractile activity.

Tucker, K. R.↗
NASA NTRS1981

Using sentence combining in technical writing classes

Sentence combining exercises are advanced as a way to teach technical writing style without reliance upon abstractions, from which students do not learn. Such exercises: (1) give students regular writing practice; (2) teach the logic of sentence structure, sentence editing, and punctuation; (3) paragraph development and organization; and (4) rhetorical stance. Typical sentence, paragraph, and discourse level sentence combining exercises are described.

Rosner, M.↗
NASA NTRS1981

Orthostatic fluid-electrolyte and endocrine responses in fainters and nonfainters

The responses to orthostasis of fluid-electrolyte and endocrine indicators in persons subject and not subject to fainting during tilting are investigated, along with the effects of heat acclimatization and physical training on those responses. Plasma volume and electrolytes and plasma vasopressin and renin activity were determined in tilt-table tests conducted before and after an eight-day period of daily heat acclimation during exercise at 50% maximal oxygen uptake at 40 C, or a control period of exercise at 24 C. Half of the 10 subjects in the study, regardless of exercise regime, showed improved orthostatic reactions in the second tilting test, related to increases in post-tilt plasma volume and potassium concentration, particularly in the nonfainters. In the first test, plasma renin activity is observed to increase fivefold and plasma vasopressin 50 times after the transition from the supine to the orthostatic positions; the respective increases were reduced by 50 and 75% in the second test. The fainters also exhibit a greater increase in vasopressin and a lower increase in renin activity upon tilting than the nonfainters. Results indicate the orthostatic-induced vasopressin increase to be related to volume control independent of renin activity.

Shvartz, E.↗
NASA NTRS1982

Effect of physical training in cool and hot environments on +Gz acceleration tolerance in women

Acceleration tolerance, plasma volume, and maximal oxygen uptake were measured in 15 healthy women before and after submaximal isotonic exercise training periods in cool and hot environments. The women were divided on the basis of age, maximal oxygen uptake, and +Gz tolerance into three groups: a group that exercised in heat (40.6 C), a group that exercised at a lower temperature (18.7 C), and a sedentary control group that functioned in the cool environment. There was no significant change in the +Gz tolerance in any group after training, and terminal heart rates were similar within each group. It is concluded that induction of moderate acclimation responses without increases in sweat rate or resting plasma volume has no influence on +Gz acceleration tolerance in women.

Brock, P. J.↗
NASA NTRS1986

Biomedical support of man in space

The effects of G and/or exercise on cardiopulmonary adjustments to stresses are studied. The control of the cardiopulmonary system is examined using simulated microgravity (recumbency, immersion, lower body positive pressure, and 6-deg head-down tilt) and increased acceleration. It is observed that at rest and during exercise in simulated zero-6 environments, the stroke volume and cardiac output are initially increased and then (after prolonged exposure) return to prezero-G levels. Cardiovascular responses to increased gravity (1, 2, and 3 G) at rest and during exercise are analyzed; a decrease in plasma volume resulting in decreases in stroke volume and cardiac output, and an increase in heart rate are detected.

Pendergast, D. R.↗
NASA NTRS1987

Relationships between coronary heart disease risk factors and serum ionized calcium in Kennedy Space Center Cohort

Kennedy Space Center (KSC) employees are reported to be at high risk for coronary heart disease (CHD). Risk factors for CHD include high serum total cholesterol levels, low levels of high-density lipoprotein cholesterol (HDLC), elevated triglyceride, smoking, inactivity, high blood pressure, being male, and being older. Higher dietary and/or serum calcium Ca(++) may be related to a lower risk for CHD. Fifty men and 37 women participated. Subjects were tested in the morning after fasting 12 hours. Information relative to smoking and exercise habits was obtained; seated blood pressures were measured; and blood drawn. KCS men had higher risk values than KCS women as related to HDLC, triglycerides, systolic blood pressure, and diastolic blood pressure. Smoking and nonsmoking groups did not differ for other risk factors or for serum Ca(++) levels. Exercise and sedentary groups differed in total cholesterol and triglyceride levels. Serum Ca(++) levels were related to age, increasing with age in the sedentary group and decreasing in the exercisers, equally for men and women. It is concluded that these relationships may be significant to the risk of CHD and/or the risk of bone demineralization in an aging population.

Goodwin, Lisa Ann↗
NASA NTRS1986

Operation of the HP2250 with the HP9000 series 200 using PASCAL 3.0

A computer program has been written to provide an interface between the HP Series 200 desktop computers, operating under HP Standard Pascal 3.0, and the HP2250 Data Acquisition and Control System. Pascal 3.0 for the HP9000 desktop computer gives a number of procedures for handling bus communication at various levels. It is necessary, however, to reach the lowest possible level in Pascal to handle the bus protocols required by the HP2250. This makes programming extremely complex since these protocols are not documented. The program described solves those problems and allows the user to immediately program, simply and efficiently, any measurement and control language (MCL/50) application with a few procedure calls. The complete set of procedures is available on a 5 1/4 inch diskette from Cosmic. Included in this group of procedures is an Exerciser which allows the user to exercise his HP2250 interactively. The exerciser operates in a fashion similar to the Series 200 operating system programs, but is adapted to the requirements of the HP2250. The programs on the diskette and the user's manual assume the user is acquainted with both the MCL/50 programming language and HP Standard Pascal 3.0 for the HP series 200 desktop computers.

Perry, John↗
NASA NTRS1990

Experiments and other methods for developing expertise with design of experiments in a classroom setting

The only way to gain genuine expertise in Statistical Process Control (SPC) and the design of experiments (DOX) is with repeated practice, but not on canned problems with dead data sets. Rather, one must negotiate a wide variety of problems each with its own peculiarities and its own constantly changing data. The problems should not be of the type for which there is a single, well-defined answer that can be looked up in a fraternity file or in some text. The problems should match as closely as possible the open-ended types for which there is always an abundance of uncertainty. These are the only kinds that arise in real research, whether that be basic research in academe or engineering research in industry. To gain this kind of experience, either as a professional consultant or as an industrial employee, takes years. Vast amounts of money, not to mention careers, must be put at risk. The purpose here is to outline some realistic simulation-type lab exercises that are so simple and inexpensive to run that the students can repeat them as often as desired at virtually no cost. Simulations also allow the instructor to design problems whose outcomes are as noisy as desired but still predictable within limits. Also the instructor and the students can learn a great deal more from the postmortum conducted after the exercise is completed. One never knows for sure what the true data should have been when dealing only with real life experiments. To add a bit more realism to the exercises, it is sometimes desirable to make the students pay for each experimental result from a make-believe budget allocation for the problem.

Patterson, John W.↗
NASA NTRS1990

Effects of microgravity on rat muscle

It is well known that humans exposed to long term spaceflight experience undesirable progressive muscle weakness and increased fatigability. This problem has prompted the implementation of inflight exercise programs because most investigators believe that the major cause of diminished muscle performance is a combination of disuse and decreased workload. Inflight exercise has improved muscle health, but deficits have persisted, indicating that either the regimens utilized were suboptimal or there existed additional debilitating factors which were not remedied by exercise. Clarification of this question requires an improved understanding of the cellular and molecular basis of spaceflight-induced muscle deterioration. To this end, multiple investigations have been performed on the muscles from rats orbited 5 to 22 days in Cosmos biosatellites and Spacelab-3 (2,4,5,8,10 to 14,16,18,19,21 to 23,25,27,28). The eight Cosmos 1887 investigations examined the structural and biochemical changes in skeletal and cardiac muscles of rats exposed to microgravity for 12.5 days and returned to terrestrial gravity 2.3 days before tissues were collected. Even though interpretation of these results was complicated by the combination of inflight and postflight induced alterations, the consensus is that there is marked heterogeneity in both degree and type of responses from the whole muscle level down to the molecular level. Collectively, the muscle investigations of Cosmos 1887 clearly illustrate the wide diversity of muscle tissue responses to spaceflight. Judging from the summary report of this mission, heterogeneity of responses is not unique to muscle tissue. Elucidating the mechanism underlying this heterogeneity holds the key to explaining adaptation of the organism to prolonged spaceflight.

Riley, D. A.↗
NASA NTRS1990

An approach to counteracting long-term microgravity-induced muscle atrophy

To find means of alleviating muscle atrophy induced by long-term microgravity, the effects of a 19-week-long heavy-resistance training regime (using either concentric muscle actions only or concentric and eccentric muscle actions) on the strengths of the exercised knee extensor muscle group were investigated in two groups of male human subjects performing two types of training exercises: supine leg press or/and seated knee extension. Results show that a training program in which both the concentric and the eccentric muscle action was performed led to substantially greater increases in maximal muscle strength than when only concentric exercises were performed.

Tesch, P. A.↗
NASA NTRS1992

Training-induced alterations in young and senescent rat diaphragm muscle

The effect of progressive treadmill exercise on oxidative capacity in three specific diaphragm muscle fiber types and on the capillary density of known fiber types was investigated in young (5 month) and senescent (23 months or older) rats. All animals were trained for 1 hr/day, 5 days weekly, for 10 weeks. Measurements of succinate dehydrogenase activity showed significant increases in all three fiber types in both the young and the senescent trained animals, compared with their sedentary controls. Fiber size and capillary density were not affected by exercise or age. The results demonstrate that the senescent costal diaphragm maintains its ability to adapt to an increased metabolic demand brought about by locomotor exercises.

Gosselin, Luc E.↗
NASA NTRS1992

Effect of hindlimb unweighting on tissue blood flow in the rat

This study characterized distribution of blood flow in the rat during hindlimb unweighting (HU), and post-HU standing and exercise. The relationship between reduced hindlimb blood flow and the previously observed elevation in anaerobic metabolism observed with contractile activity in the atrophied soleus muscle was examined (Witzmann et al., 1992). Blood flow was measured during unweighting, normal standing, and running on a treadmill (15 m/min), after 15 days of HU or cage control. For another group blood flow was measured during preexercise treadmill standing and treadmill running. During unweighting, PE standing, and running no difference in soleus blood flow was observed between groups. Muscles composed mainly of fast twitch glycolytic fibers received greater blood flow during chronic unweighting. With exercise blood flow to visceral organs was reduced in control animals, a similar change was not seen in 15 day HU rats. These changes suggest a reduction in the ability of the sympathetic nervous system to distribute cardiac output after chronic HU. A reduction in blood flow to the soleus during exercise was not observed after HU and so does not explain the increased dependence of the atrophied soleus on anerobic energy production during contractile activity.

Mcdonald, K. S.↗
NASA NTRS1992

Fuzzy set approach to quality function deployment: An investigation

The final report of the 1992 NASA/ASEE Summer Faculty Fellowship at the Space Exploration Initiative Office (SEIO) in Langley Research Center is presented. Quality Function Deployment (QFD) is a process, focused on facilitating the integration of the customer's voice in the design and development of a product or service. Various input, in the form of judgements and evaluations, are required during the QFD analyses. All the input variables in these analyses are treated as numeric variables. The purpose of the research was to investigate how QFD analyses can be performed when some or all of the input variables are treated as linguistic variables with values expressed as fuzzy numbers. The reason for this consideration is that human judgement, perception, and cognition are often ambiguous and are better represented as fuzzy numbers. Two approaches for using fuzzy sets in QFD have been proposed. In both cases, all the input variables are considered as linguistic variables with values indicated as linguistic expressions. These expressions are then converted to fuzzy numbers. The difference between the two approaches is due to how the QFD computations are performed with these fuzzy numbers. In Approach 1, the fuzzy numbers are first converted to their equivalent crisp scores and then the QFD computations are performed using these crisp scores. As a result, the output of this approach are crisp numbers, similar to those in traditional QFD. In Approach 2, all the QFD computations are performed with the fuzzy numbers and the output are fuzzy numbers also. Both the approaches have been explained with the help of illustrative examples of QFD application. Approach 2 has also been applied in a QFD application exercise in SEIO, involving a 'mini moon rover' design. The mini moon rover is a proposed tele-operated vehicle that will traverse and perform various tasks, including autonomous operations, on the moon surface. The output of the moon rover application exercise is a ranking of the rover functions so that a subset of these functions can be targeted for design improvement. The illustrative examples and the mini rover application exercise confirm that the proposed approaches for using fuzzy sets in QFD are viable. However, further research is needed to study the various issues involved and to verify/validate the methods proposed.

Masud, Abu S. M.↗
NASA NTRS1992

Carotid-cardiac baroreflex response and LBNP tolerance following resistance training

The purpose of this study was to examine the effect of lower body resistance training on cardiovascular control mechanisms and blood pressure maintenance during an orthostatic challenge. Lower body negative pressure (LBNP) tolerance, carotid-cardiac baroreflex function (using neck chamber pressure), and calf compliance were measured in eight healthy males before and after 19 wk of knee extension and leg press training. Resistance training sessions consisted of four or five sets of 6-12 repetitions of each exercise, performed two times per week. Training increased strength 25 +/- 3 (SE) percent (P = 0.0003) and 31 +/- 6 percent (P = 0.0004), respectively, for the leg press and knee extension exercises. Average fiber size in biopsy samples of m. vastus lateralis increased 21 +/- 5 percent (P = 0.0014). Resistance training had no significant effect on LBNP tolerance. However, calf compliance decreased in five of the seven subjects measured, with the group average changing from 4.4 +/- 0.6 ml.mm Hg-1 to 3.9 +/- 0.3 ml.mm Hg-1 (P = 0.3826). The stimulus-response relationship of the carotid-cardiac baroreflex response shifted to the left on the carotid pressure axis as indicated by a reduction of 6 mm Hg in baseline systolic blood pressure (P = 0.0471). In addition, maximum slope increased from 5.4 +/- 1.3 ms.mm Hg-1 before training to 6.6 +/- 1.6 ms.mm Hg-1 after training (P = 0.0141). Our results suggest the possibility that high resistance, lower extremity exercise training can cause a chronic increase in sensitivity and resetting of the carotid-cardiac baroreflex.

Tatro, D. L.↗
NASA NTRS1993

Specification list and function structure for a full-body dynamometer to be used aboard Space Station Freedom

NASA has a need for a machine which can be used as an exercise device and as an instrument to measure an astronaut's muscle performance. The purpose of the exercise device is to work various muscle groups of the astronaut to prevent muscle atrophy, the loss of muscle strength and mass from prolonged exposure to a microgravity environment. The measurement part of the machine will be used to collect data on the strength and power of the astronaut's muscle groups to be used in studies examining the effects of prolonged space inhabitation. The principle device used in this machine to both exercise and measure muscle performance is the dynamometer. The dynamometer converts electrical energy to mechanical energy and mechanical energy to electrical energy or signals. The task of the designer will be to incorporate a dynamometer into a device which can meet all of the needs discussed above. This memorandum has two sections which clarify the design task of producing a full-body dynamometer. The first section is a specification list. The specification list provides the requirements that the designer must meet in his/her design. The second part is a function structure. The function structure shows graphically the flow of material, energy, and information through the machine. These two items will be used by the designer in the design process for the full-body dynamometer.

Mcmahan, Robert↗
NASA NTRS1994

The use of biomechanics in the study of movement in microgravity

As biomechanists interested in the adaptability of the human body to microgravity conditions, it appears that our job is not only to make sure that the astronauts can function adequately in space but also that they can function upon their return to Earth. This is especially significant since many of the projects now being designed at NASA concern themselves with humans performing for up to 3 years in microgravity. While the Extended Duration Orbiter flights may last 30 to 60 days, future flights to Mars using current propulsion technology may last from 2 to 3 years. It is for this range of time that the adaptation process must be studied. Specifically, biomechanists interested in space travel realize that human performance capabilities will change as a result of exposure to microgravity. The role of the biomechanist then is to first understand the nature of the changes realized by the body. These changes include adaptation by the musculoskeletal system, the nervous system, cardiorespiratory system, and the cardiovascular system. As biomechanists, it is also our role to take part in the development of countermeasure programs that involve some form of regular exercise. Exercise countermeasure programs should include a variety of modalities with full knowledge of the loads imposed on the body by these modalities. Any exercise programs that are to be conducted by the astronauts during space travel must consider the fact that the musculoskeletal and neuromuscular systems degrade as a function of flight duration. Additionally, it must be understood that the central nervous system modifies its output in the control of the human body during space flight and most importantly, we must prepare the astronauts for their return to one g.

Gregor, R. J.↗
NASA NTRS1990

Intelligent tutoring using HyperCLIPS

HyperCard is a popular hypertext-like system used for building user interfaces to databases and other applications, and CLIPS is a highly portable government-owned expert system shell. We developed HyperCLIPS in order to fill a gap in the U.S. Army's computer-based instruction tool set; it was conceived as a development environment for building adaptive practical exercises for subject-matter problem-solving, though it is not limited to this approach to tutoring. Once HyperCLIPS was developed, we set out to implement a practical exercise prototype using HyperCLIPS in order to demonstrate the following concepts: learning can be facilitated by doing; student performance evaluation can be done in real-time; and the problems in a practical exercise can be adapted to the individual student's knowledge.

Hill, Randall W., Jr.↗