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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Winds on Mars during the Viking season - Predictions based on a general circulation model with topography

The Arakawa-Mintz general circulation model of the earth has been applied to Mars at the season of the Viking Lander mission. Allowance has been made for the effects of the large Martian topography. The calculated wind fields exhibit significant zonally symmetric, topographically forced, and diurnal tidal components. Average wind speeds of 20-25 m/sec were found at three possible landing sites, with wind speeds occasionally reaching values as much as a factor of 2 larger than these average values. If buffering by CO2 adsorbed in the regolith can be neglected, a pressure decline of about 0.8 mb is expected over the first two months of operation of the first lander.

Pollack, J. B.↗
NASA NTRS1976

Emission spectrometric arcing procedure with minimal effect of chemical form of sample

This paper describes a study of matrix effects related to the chemical form of materials analyzed. The study was made using an arc in argon buffered with silver chloride. The effect of chemical form was minimal for a variety of metals, oxides, and carbides representing the most refractory compounds and thermally stable metal-containing molecules. Among these, only four of the most refractory materials known showed significant emission depressions due to incomplete volatilization in the arc system. These results are discussed in terms of vapor pressure of the solid materials placed on the anodes and dissociation reactions of the molecules in the gaseous environment.

Gordon, W. A.↗
NASA NTRS1976

Hardware additions to microprocessor architecture aid software development

An address trap (breakpoint) mechanism and last-in-first-out (LIFO) address stack are suggested as two additions to the basic microprocessor architecture whose functions are solely to aid the programmer. These devices provide the programmer with the ability to specify address breakpoints and to trace program execution back through N instructions, where N is the depth of the stack. Both devices, plus interface logic and buffering, have been designed for an INTEL 8080-based system using approximately 25 integrated-circuit packages.

Sievers, M. W.↗
NASA NTRS1976

Electrophoretic characterization of aldehyde-fixed red blood cells, kidney cells, lynphocytes and chamber coatings

Ground-based electrokinetic data on the electrophoresis flight experiment to be flown on the Apollo-Soyuz Test Project experiment MA-011 are stipulated. Aldehyde-fixed red blood cells, embryonic kidney cells and lymphocytes were evaluated by analytical particle electrophoresis. The results which aided in the interpretation of the final analysis of the MA-011 experiment are documented. The electrophoresis chamber surface modifications, the buffer, and the material used in the column system are also discussed.

Source record↗
NASA NTRS1976

Continuous-flow electrophoretic separator for biologicals

In the near absence of gravity, a continuous-flow type of electrophoretic separator can be operated with a much thicker separation chamber than is possible under 1 g conditions. This should permit either better resolution or shorter separation time per unit of sample. An apparatus to perform experiments on sounding rockets is under development and will be described. The electrophoresis cell is 5 mm thick by 5 cm wide with 10 cm long electrodes. It is supplied with buffer, sample, and coolant at about 4 C through the use of a passive refrigerant system. UV sample detection and provision for recovery and cold storage of up to 50 sample fractions are now being added to the basic unit. A wide range of operating conditions are electronically programmable into the unit, even up to a short time before flight, and a further range of some parameters can be achieved by exchanging power supplies and by changing gears in the motor drive units of the pump. The preliminary results of some separation studies on various biological products using a commercially available electrophoretic separator are also presented.

Mccreight, L. R.↗
NASA NTRS1977

Electrophoresis experiment. Experiment MA-014

A continuous free-flow electrophoresis study was conducted during the Apollo-Soyuz Test Project Mission to investigate and evaluate the increase in sample flow rate and sample resolution achievable in space. The electrophoresis equipment was designed for the separation of four mixtures of biological cells with variable sample flow rates, buffer flow rates, and electric field gradients. Separation quality was assessed by measuring the light from a quartz lamp through the electrophoresis channel and onto a photodiode system. The data evaluation indicates that all monitored systems operated correctly during the experiment. The optical system produced a light that was too bright to discern true cell distributions, but final analysis of scientific data by computer processing shows the expected distribution of separated cells.

Hannig, K. H.↗
NASA NTRS1976

Cerebellar pressor response in the dog

A fastigial pressor response has been elicited in the anesthetized mongrel dog. Stimulation within the rostral portions of this nucleus results in mean arterial pressure rises up to 150 mmHg above control. A proportional tachycardia is simultaneously evoked which may rapidly attain heart rates of 190 beats/min above control levels. Peak tachycardias immediately subside and often the heart rate declines below control values during stimulation while arterial pressure remains elevated. When either the carotid sinuses were isolated by ligation or a bilateral vagotomy was performed, the fastigial tachycardia was sustained. The response could still be attained when submaximal doses of alpha-chloralose anesthesia or high levels of barbiturates (30-40 mg/kg) were given. Both portions of the response result from widespread sympathetic activation; however, buffering of the response through the baroreceptor reflexes is only demonstrated in the cardiac segment of the response.

Dormer, K. J.↗
NASA NTRS1976

Intensified charge coupled devices for ultra low light level imaging

Development of a sensor incorporating a CCD and photocathode for operation in the electron bombarded mode in both a magnetic and an electrostatic focussed, gated configuration is described. Initial format size is 100 x 160 pixels with eventual growth to 400 x 400 pixels. The sensor is part of a digital camera system which includes the low level video conditioning electronics, a camera controller, a high speed buffer memory, and digital recording and display electronics. The memory uses CMOS/SOS and has a capacity of 1.6 Mbits with operating rates of 48 Mbits/sec. Individual frames are co-added to provide wide dynamic range and photometric precision better than 1%. A 4-bit video quantization is used to increase the photon counting detection rate before coincidence losses become serious.

Sobieski, S.↗
NASA NTRS1977

A parametric study of the copper chloride laser

A parametric study of the double-pulsed copper chloride laser is reported. The effects of a wide range of variables on the laser energy density and on three characteristic time intervals (the minimum, maximum, and optimum delay time) between the two electrical-discharge pulses were studied. The geometric variables investigated included a tube diameter of 2.3 to 40 mm and a tube length of 3 to 60 cm. Three buffer gases, helium, neon, and argon, were studied over the pressure range 0.5-50 torr, and the tube temperature was varied from 270 to 500 C. The energy density and voltage of both the dissociation and pumping pulse were varied independently from less than 1 mJ/cu cm at 8.5 kV to over 500 mJ/cu cm at 20 kV. The optimum conditions for maximum laser energy density were found to be with 20 torr neon in a 10-mm by 30-cm tube at 400 C. The maximum energy density obtained was 22 microjoules/cu cm.

Nerheim, N. M.↗
NASA NTRS1977

Addition of HCl to the double-pulse copper chloride laser

Addition of small amounts of hydrogen chloride to the buffer gas of a double-pulse CuCl laser causes an increase in the production of copper atoms in the ground state. A maximum laser energy increase of 15% was observed and the span of delay times for which laser action occurred increased.

Vetter, A. A.↗
NASA NTRS1977

The yield of N/2D/ atoms in the dissociative recombination of NO/+/

The quantum yield or branching ratio of N(2D) atoms formed in the reaction e + NO(+) yields N + O was measured to be 76% plus or minus 6%. Photoionization of buffered nitric oxide by a flash lamp was studied using time-resolved atomic absorption. Atoms were produced both by direct photodissociation and by dissociative recombination, and these two effects were separated by means of SF6 as an electron scavenger.

Kley, D.↗
NASA NTRS1976

Solubility of Cr, Ti, and Al in co-existing olivine, spinel, and liquid at 1 atm

The partitioning of chromium between olivines, spinels and silicate liquids was studied as a function of temperature, oxygen fugacity, and cooling rate between 1175 and 1300 C and redox states near the Fe-FeO buffer. It is found that the weight ratio of Cr2O3 in olivine to that in the liquid increases slightly as oxygen fugacity decreases, but the effect is very small. The cooling experiments showed that the Cr2O3 content does not re-equilibrate with cooling.

Akella, J.↗
NASA NTRS1978

Self-sterilizing canister

Canister, originally conceived for remote sterilization of spacecraft packages, could be used terrestrially to handle samples in biologically hazardous environments. Multiwalled canister includes inner layer of pyrotechnic powder. For sterilization, electrically activated squib ignites powder, raising temperature of outer surface of canister to 230 degrees centigrade for several minutes. Thermal-buffer inner layer prevents inside temperature for exceeding 100 degrees centigrade to protect contents from damage. Samples in field hospitals and other emergency situations could also be handled by equipment.

Yang, L. C.↗
NASA NTRS1978

Investigation of a high speed data handling system for use with multispectral aircraft scanners

A buffer memory data handling technique for use with multispectral aircraft scanners is presented which allows digital data generated at high data rates to be recorded on magnetic tape. A digital memory is used to temporarily store the data for subsequent recording at slower rates during the passive time of the scan line, thereby increasing the maximum data rate recording capability over real-time recording. Three possible implementations are described and the maximum data rate capability is defined in terms of the speed capability of the key hardware components. The maximum data rates can be used to define the maximum ground resolution achievable by a multispectral aircraft scanner using conventional data handling techniques.

Kelly, W. L.↗
NASA NTRS1977

Digital high density (80 Mb/s) tape

Work with a state-of-the-art high density PCM tape recorder reproducer system is described. The tape recorder is designed for 80 Mb/s operation at an overall bit error rate of .00001and for 40 Mb/s operation at .000001. The article describes the process of measuring the error rate. Also detailed is a data rate buffer designed for use in recent radar experiments and generalizable to most potential uses of the recorder system.

Donner, M. D.↗
NASA NTRS1976

Parametric analyses of planned flowing uranium hexafluoride critical experiments

Analytical investigations were conducted to determine preliminary design and operating characteristics of flowing uranium hexafluoride (UF6) gaseous nuclear reactor experiments in which a hybrid core configuration comprised of UF6 gas and a region of solid fuel will be employed. The investigations are part of a planned program to perform a series of experiments of increasing performance, culminating in an approximately 5 MW fissioning uranium plasma experiment. A preliminary design is described for an argon buffer gas confined, UF6 flow loop system for future use in flowing critical experiments. Initial calculations to estimate the operating characteristics of the gaseous fissioning UF6 in a confined flow test at a pressure of 4 atm, indicate temperature increases of approximately 100 and 1000 K in the UF6 may be obtained for total test power levels of 100 kW and 1 MW for test times of 320 and 32 sec, respectively.

Rodgers, R. J.↗
NASA NTRS1976

Plasma core reactor applications

Analytical and experimental investigations were conducted to demonstrate the feasibility of fissioning uranium plasma core reactors and to characterize space and terrestrial applications for such reactors. Uranium hexafluoride fuel is injected into core cavities and confined away from the surface by argon buffer gas injected tangentially from the peripheral walls. Radiant heat transfer calculations were performed for a six-cavity reactor configuration. Axial working fluid channels are located along a fraction of each cavity peripheral wall. Results of calculations for outward-directed radiant energy fluxes corresponding to radiating temperatures of 2000 to 5000 K indicate total operating pressures from 80 to 650 atm, centerline temperatures from 6900 to 30,000 K, and total radiated powers from 25 to 2500 MW, respectively. Applications are described for this type of reactor such as (1) high-thrust, high specific impulse space propulsion, (2) highly efficient systems for generation of electricity, and (3) hydrogen or synthetic fuel production systems using the intense radiant energy fluxes.

Latham, T. S.↗
NASA NTRS1978

Loran-C flight test software

The software package developed for the KIM-1 Micro-System and the Mini-L PLL receiver to simplify taking flight test data is described along with the address and data bus buffers used in the KIM-1 Micro-system. The interface hardware and timing are also presented to describe completely the software programs.

Nickum, J. D.↗