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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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NASA NTRS1987

Measurement of differential proton spectra onboard the Space Shuttle using a thermoluminescent dosimetry system

An experimental technique that permits the extraction of orbit-averaged, differential energy spectra of trapped radiation belt protons using simple passive detectors is described. An inversion technique is used for the data analysis. The basic principle of the described system is measurement of the energy deposited in six thermoluminescent (TLD) detector assemblies behind various spherical absorbers. The technique has been applied to a detector assembly flown on four Shuttle flights. Although severe restraints were placed on the flight package, the differential energy spectra derived from these measurements are in good agreement with analytical results using a modified trapped proton environment model. The technique shows good promise for measuring the spectra in low inclination orbits where the flux of high energy galactic cosmic rays protons is small. Modifications to the detector assembly to improve the accuracy and to extend the range of the system to higher energies are suggested.

STS-51J Shuttle Project↗

NASA NTRS1987

Spacelab experiments on space motion sickness

Recent research results from ground and flight experiments on motion sickness and space sickness conducted by the Man Vehicle Laboratory are reviewed. New tools developed include a mathematical model for motion sickness, a method for quantitative measurements of skin pallor and blush in ambulatory subjects, and a magnitude estimation technique for ratio scaling of nausea or discomfort. These have been used to experimentally study the time course of skin pallor and subjective symptoms in laboratory motion sickness. In prolonged sickness, subjects become hypersensitive to nauseogenic stimuli. Results of a Spacelab-1 flight experiment are described in which four observers documented the stimulus factors for and the symptoms/signs of space sickness. The clinical character of space sickness differs somewhat from acute laboratory motion sickness. However SL-1 findings support the view that space sickness is fundamentally a motion sickness. Symptoms were subjectively alleviated by head movement restriction, maintenance of a familiar orientation with respect to the visual environment, and wedging between or strapping onto surfaces which provided broad contact cues confirming the absence of body motion.

Flight Experiment↗

NASA NTRS1986

Long term effects of low doses of 56Fe ions on the brain and retina of the mouse: ultrastructural and behavioral studies

Eight month old male C57BL6 mice were exposed without anesthesia to whole-body irradiation in circular holders. The mice were tested for behavioral decrements after 0.5 and 50 rads of Fe particle irradiation at 6 and 12 months post irradiation to obtain long term results. A standard maze was used and the animals were timed for completion thereof. A string test also was administered to the mice, testing their ability to grasp and move along a string to safety. The results from animals exposed to 50 rads were significantly different from [correction of fron] control results to p = < .001 in both systems of testing. The hippocampus (believed to be the location of environmental interaction in the brain) and the retina were examined for ultrastructural changes. The ultrastructural changes were similar to those we found in our Cosmos 782, 936 and in our Argon experiments. The mouse data indicate that iron particles were able to induce long term changes in the central nervous system which lead to behavioral impairment.

NASA Program Space Medicine↗

NASA NTRS1987

Nutrients affecting brain composition and behavior

This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

NASA Program Space Medicine↗

NASA NTRS1987

The preservation of urine samples for determination of renal stone risk factors

A preservation technique for urine specimens before determination of stone risk factors was evaluated. The purpose of these experiments was to prove the effectiveness of the preservatives used to prevent changes in the concentrations of those constituents measured. Measured concentrations in fresh specimens were compared with those in the same specimens after storage with the preservatives. Refrigeration at 4 degrees C up to five days was appropriate in a laboratory setting, as no significant changes in urinary concentrations occurred. Refrigeration, however, did not offer a convenient method for shipping. Chemical preservation was found to be an effective alternative to refrigeration. Thymol prevented changes in concentration of pH, citrate, uric acid, sulfate, sodium, potassium, and cyclic AMP, while a mixture of hydrochloric (HCl) acid and boric acid prevented changes in calcium, magnesium, phosphorus, oxalate, ammonium, and creatinine. Thus, the addition of thymol or HCl/boric acid to urine specimens will prevent significant changes in the concentrations of stone risk factors.

Non-NASA Center↗

NASA NTRS1987

Adaptation of muscle gene expression to changes in contractile activity

A review of the existing literature regarding the effects of different types of physical activities on the gene expression of adult skeletal muscles leads us to conclude that each type of exercise training program has, as a result, a different phenotype, which means that there are multiple mechanisms, each producing a unique phenotype. A portion of the facts which support this position is presented and interpreted here. [Abstract translated from the original French by NASA].

NASA Program Space Medicine↗

NASA NTRS1987

Exploring flight crew behaviour

A programme of research into the determinants of flight crew performance in commercial and military aviation is described, along with limitations and advantages associated with the conduct of research in such settings. Preliminary results indicate significant relationships among personality factors, attitudes regarding flight operations, and crew performance. The potential theoretical and applied utility of the research and directions for further research are discussed.

NASA Discipline Space Human Factors↗

NASA NTRS1987

Galactic HZE propagation through the Earth's atmosphere

A comprehensive physical model for galactic heavy ion propagation is presented. The nuclear fragmentation model is a simplified physical model but contains the major processes of importance to galactic ions. Comparison is made to measurements of atmospheric ion fluence and the limitations of these comparisons are discussed.

NASA Discipline Radiation Health↗

NASA NTRS1987

An algorithm for a semiempirical nuclear fragmentation model

In the present paper, an algorithm for HZE (High Charge and Energy) fragmentation based upon a combination of a two step abrasion/ablation model and electromagnetic dissociation is presented. Development of the model and detailed comparison with available experimental data are given elsewhere. The abrasion process accounts for the removal of nuclear matter in the overlap region of the colliding ions. An average transmission factor is used for the projectile and target nuclei at a given impact parameter to account for the finite mean free path in nuclear matter. The ions are treated otherwise on a geometric basis assuming uniform spheres. The ablation process is treated as a single nucleon-evaporation for every 10 MeV of excitation energy as used by Bowman in the original form of the model. The charge distribution of final fragments are calculated according to the Rudstam formula, except for some correction in mass 5, 8 and 9 fragments which show strong structure effects and correspondingly significant deviation from Rudstam's values. The nuclear electromagnetic dissociation is based on the Weizsacker-Williams (WW) method of virtual quanta where due to its simplicity, the virtual photon spectrum for individual multipoles, and finite extent of the charge distribution are not included. Comparisons of the model are made with the available experimental data here and more extensively elsewhere.

NASA Program Space Medicine↗

NASA NTRS1987

Exclusive measurements of mean pion multiplicities in 4He-nucleus reactions from 200 to 800 MeV/nucleon

Mean multiplicities of pi+ and pi- in 4He collisions with C, Cu, and Pb at 200, 600, and 800 MeV/u, and with C and Pb at 400 MeV/u have been measured using the large solid angle detector Diogene. The independence of pion multiplicity on projectile incident energy, target mass and proton multiplicity is studied in comparison with intra-nuclear cascade predictions. The discrepancy between experimental results and theory is pointed out and discussed.

NASA Discipline Radiation Health↗

NASA NTRS1985

The stopping of deuterons in lithium

The interaction of 52 MeV deuterons with lithium was investigated, in view of the optimization of a lithium target for an intense neutron source based on the d-Li stripping reaction. The experimental results are compared with theoretical calculations obtained from an updated version of the Bragg code. This code describes in detail the interaction of charged particles with matter. Within the experimental uncertainties the theoretical results are well reproduced by the experiments.

NASA Program Space Medicine↗

NASA NTRS1986

Performance Evaluation Tests for Environmental Research (PETER): evaluation of 114 measures

The goal of the Performance Evaluation Tests for Environmental Research (PETER) Program was to identify a set of measures of human capabilities for use in the study of environmental and other time-course effects. 114 measures studied in the PETER Program were evaluated and categorized into four groups based upon task stability and task definition. The Recommended category contained 30 measures that clearly obtained total stabilization and had an acceptable level of reliability efficiency. The Acceptable-But-Redundant category contained 15 measures. The 37 measures in the Marginal category, which included an inordinate number of slope and other derived measures, usually had desirable features which were outweighed by faults. The 32 measures in the Unacceptable category had either differential instability or weak reliability efficiency. It is our opinion that the 30 measures in the Recommended category should be given first consideration for environmental research applications. Further, it is recommended that information pertaining to preexperimental practice requirements and stabilized reliabilities should be utilized in repeated-measures environmental studies.

NASA Program Space Medicine↗

NASA NTRS1986

Theoretical contributions to coherent pion production in subthreshold and relativistic heavy-ion collisions

The analytic results from a microscopic calculation for pion production in heavy-ion collisions at intermediate to relativistic energies both above and below pion threshold are presented and the most important terms that contribute to the pion spectrum are determined. The energy dependence and the effects on the pion spectrum due to the various parameters in the theory are examined. The model is applied to coherent pion-production in 16O + 12C collisions.

NASA Discipline Number 22-70↗

NASA NTRS1986

Measurements of n-p correlations in the reaction of relativistic neon with uranium

We report a preliminary measurement of coincident neutron-proton pairs emitted at 45 degrees in the interaction of 400, 530, and 650 MeV/A neon beams incident on uranium. Charged particles were identified by time of flight and momentum, as determined in a magnetic spectrometer. Neutral particles were detected using a thick plastic scintillator, and their time of flight was measured between an entrance scintillator, triggered by a charged particle, and the neutron detector. The scatter plots and contour plots of neutron momentum vs. proton momentum appear to show a slight correlation ridge above an uncorrelated background. The projections of this plane on the n-p momentum difference axis are essentially flat, showing a one standard deviation enhancement for each of the three beams energies. At each beam energy, the calculated momentum correlation function for the neutron-proton pairs is enhanced near zero neutron-proton momentum difference by approximately one standard deviation over the expected value for no correlation. This enhancement is expected to occur as a consequence of the attractive final state interaction between the neutron and proton (i.e., virtual or "singlet" deuterons). The implications of these measurements are discussed.

NASA Program Space Medicine↗

NASA NTRS1986

Assessing fatigue

Despite impressive advances in aircraft technology over the past several decades and an overall decline in the airline accident rate since the introduction of turbine-powered aircraft, flight crew performance problems continue to dominate air transport accident statistics. Researchers have offered many hypotheses to explain this finding, and interest in pilot fatigue has stimulated a large volume of laboratory research. Much of this work, however, is difficult to generalize and to apply to the real world of flight operations, and researchers disagree about the extent and operational significance of fatigue-related reductions in pilot performance. As a result, in 1980 Congress asked the National Aeronautics and Space Administration to undertake a comprehensive research program to assess whether fatigue-related problems are prevalent in long- and short-haul flying. The two major goals of this project are: (1) to assess the psychophysiological effects on pilot performance of flying various types of flight and duty cycles, and (2) to determine the operational significance to flight safety and efficiency of flying these flight and duty cycles.

NASA Discipline Space Human Factors↗

NASA NTRS2001

Modeling and simulation for space medicine operations: preliminary requirements considered

The NASA Space Medicine program is now developing plans for more extensive use of high-fidelity medical simulation systems. The use of simulation is seen as means to more effectively use the limited time available for astronaut medical training. Training systems should be adaptable for use in a variety of training environments, including classrooms or laboratories, space vehicle mockups, analog environments, and in microgravity. Modeling and simulation can also provide the space medicine development program a mechanism for evaluation of other medical technologies under operationally realistic conditions. Systems and procedures need preflight verification with ground-based testing. Traditionally, component testing has been accomplished, but practical means for "human in the loop" verification of patient care systems have been lacking. Medical modeling and simulation technology offer potential means to accomplish such validation work. Initial considerations in the development of functional requirements and design standards for simulation systems for space medicine are discussed.

Non-programmatic↗

NASA NTRS1986

Delta excitations and shell-model information in heavy-ion, charge-exchange reactions

We calculate total cross sections for coherent pion production using localized plane-wave approximations for the shell-structure of valence nucleons that are excited to delta particles in the intermediate state in the (12C, 12B) and (12C, 12N) charge-exchange, heavy-ion reactions. We find comparable agreement to projectile downshift data for 12C(12C, 12B)12N. Then we improve the formalism by replacing the localized plane wave bound states with harmonic oscillator states which are imbedded in a multipole expansion approach and calculate pion differential cross sections to test for the sensitivity of the spectra to the single-particle mass parameter.

NASA Program Space Medicine↗

NASA NTRS1986

Quantum mechanical signature in exclusive coherent pion production

We calculate the coherent production of pions from subthreshold to relativistic energies in heavy-ion collisions using a quantum, microscopic, many-body model. For the first time, in this approach, we use harmonic oscillator wave functions to describe shell-model information. The theoretical quantum mechanical results obtained for the pion spectra represent an important improvement over our previous microscopic, many-body calculations.

NASA Discipline Radiation Health↗