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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Liquid breathing - Prevention of pulmonary arterial-venous shunting during acceleration.

Dependent pulmonary atelectasis, arterial-venous shunting, and downward displacement of the heart caused by the gravitational-inertial force environment were prevented in dogs breathing oxygenated liquid fluorocarbon in a whole-body water-immersion respirator. Partial closure of the major airways during part of the expiratory phase of liquid respiration was a significant problem initially but was minimized in subsequent studies.

Sass, D. J.↗
NASA NTRS1970

The Value of Continued Followup in a Preventive Medicine Program

Continued monitoring of hypertension and cholesterol levels in NASA employees by regularly scheduled medical examinations prevents an increase in employee disability and cardiovascular mortality rates. Adequate therapeutic control for younger hypertensive employees is demonstrated by records on mortality and heart diseases over a period of 28 months. It confirmed the importance of systolic blood pressure as diagnostic tool for the inherent risk factor. The prevalence of additional coronary risk factors among employees with hypercholesterolemia is considerably less than in employees with hypertension.

Villafana, C.↗
NASA NTRS1974

Some practical examples of cavitation erosion and their prevention

The problem of failures caused by cavitation erosion are discussed. The concepts of intensity of erosion, erosion strength, and the time dependence of erosion rate are analyzed. The relation of these parameters to system variables such as pressure and velocity, and to the properties of materials are investigated. Using several examples of actual cavitation erosion, methods of prevention and their limitations are examined.

Conn, A. F.↗
NASA NTRS1975

Chemico-therapeutic approach to prevention of dental caries

The program of chemical preventive dentistry is based primarily upon the development of a procedure for stabilizing stannous fluoride in solution by forcing it into glycerin. New topical fluoride treatment concentrates, fluoride containing gels and prophylaxis pastes, as well as a completely stable stannous fluoride dentifrice are made possible by the development of a rather complicated heat application method to force stannous fluoride into solution in glycerin. That the stannous fluoride is clinically effective in such a preparation is demonstrated briefly on orthodontic patients.

Shannon, I. L.↗
NASA NTRS1975

Prevention of design flaws in multicomputer systems

Multicomputer configurations and redundancy management techniques used in various airborne systems were investigated to determine methods to prevent and/or treat generic design flaws. The findings are intended for use in the design of a computer system for use in the space shuttle orbiter.

Source record↗
NASA NTRS1975

Prevention of thermal bending of multilayered beams and plates

By adding an extra layer to multilayer beams or plates of different isotropic materials, it is possible to prevent the thermal bending of these materials. With the proper selection of thermoelastic properties the curvature produced prior to this addition would be eliminated. Several numerical examples are presented for various temperature distributions. A simple experiment was conducted, involving the addition of a brass strip to a bimetallic strip made of aluminum and steel at room temperature. The trimetal strip was placed in a furnace and remained straight for varying temperatures.

Yang, J. C. S.↗
NASA NTRS1977

Muscular deconditioning and its prevention in space flight

Exercise and exercise devices on Skylab missions prevented muscle loss in spacecrews. It is concluded that muscle in space is no different from muscle on earth; if it is properly nourished and exercised at reasonable load levels, it maintains its function under weightlessness conditions.

Thornton, W. E.↗
NASA NTRS1978

Preventing radio-paging system tieup

Time-delay relay limits message time of emergency radio-paging system, thereby preventing inadvertent tieup. Relay is connected with telephone circuit and permits adjustable message time between 30 and 55 seconds. After that time interval, relay opens, making line free for another paging regardless of what previous caller did with his telephone.

Jasmin, J. P.↗
NASA NTRS1978

The control and prevention of seizures in children, a developmental and environmental approach

The clinical effectiveness of neurophysiological and developmental factors in controlling and preventing seizure mechanisms is detailed. It is shown that as cortical control advances with maturation, it requires increasingly severe environmental adversity to release this residual defensive reflex mechanism. Administration of anticonvulsant drugs is discouraged because of possible undesirable neuronal effects on the very young brain.

Lewinn, E. B.↗
NASA NTRS1980

Ground experiments for finding principles and working out methods for preventing adverse effects of weightlessness on the human organism

A comparative assessment of the effectiveness of different prophylactic procedures to prevent the adverse effects of weightlessness is presented. It is concluded that: physical training is most effective but no single method by itself produces the full effect, and an adjustment of regimes to one another enhances the effect. The approved complex of prophylactic procedures affected basic changes occurring in hypokinesia: deficit of muscular activity, no or reduced BP hydrostatic component, reduced volume of blood circulation, reduced hydration level, and the application of various prophylactic complexes during 49 day antiorthostatic hypodynamia eliminated or reduced the adverse effects of weightlessness in simulation.

Kakurin, L. I.↗
NASA NTRS1954

A Procedure for the Design of Air-Heated Ice-Prevention Systems

A procedure proposed for use in the design of air-heated systems for the continuous prevention of ice formation on airplane components is set forth. Required heat-transfer and air-pressure-loss equations are presented, and methods of selecting appropriate meteorological conditions for flight over specified geographical areas and for the calculation of water-drop-impingement characteristics are suggested. In order to facilitate the design, a simple electrical analogue was devised which solves the complex heat-transfer relationships existing in the thermal-system analysis. The analogue is described and an illustration of its application to design is given.

Neel, C. B.↗
NASA NTRS1982

Overheat Prevention in Solar-Powered Stirling Engines

Proposed controller for solar-powered Stirling engine prevents engine from burning up when energy added by Sun exceeds that withdrawn by load. Head-temperature controller used existing electrical control unit of Stirling engine to regulate power output in response to head temperature. Power out-put is varied so keeps head temperature fairly constant.

Garrigus, W. E.↗
NASA NTRS1983

Preventing Freezeup in Silicon Ribbon Growth

Carefully-shaped heat conductor helps control thermal gradients crucial to growth of single-crystal silicon sheets for solar cells. Ends of die through which silicon sheet is drawn as ribbon from molten silicon. Profiled heat extractor prevents ribbon ends from solidifying prematurely and breaking.

Mackintosh, B.↗
NASA NTRS1981

Wind-tunnel investigation of the tail-spoiler concept for stall-prevention on general aviation airplanes

The longitudinal aerodynamic characteristics of a full scale, single engine general aviation airplane equipped with an angle of attack limiting concept which used a tail mounted spoiler for stall prevention were investigated. The tail spoiler was deployed as a nonlinear function of changes in angle of attack in a narrow angle of attack range immediately preceding the stall angle. Spoiler deployment produced a nose down moment which limited the nose up trim capability of the elevator to an angle of attack below the stall angle of the airplane. The tail spoiler system produced significant increases in longitudinal stability and elevator hinge moments near the stall. The effects of power, flaps, and center of gravity position are also studied.

Satran, D. R.↗
NASA NTRS1981

Method of preventing oxidation of graphite fireproof material

A method of preventing oxidation of graphite fireproof material is given. A blend of 1 to 33 weight parts alumina and 3 to 19 parts of K2O + Na2O in 100 parts of SiO2 is pulverized followed by addition of 5 to 160 parts of silicon carbide powder in 100 parts of the mixture. This is thoroughly blended and coated on the surface of graphite fireproof material.

Yamauchi, S.↗