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NASA NTRS1972

Development of a liquid metal slip ring

A liquid metal slip ring/solar orientation mechanism was designed and a model tested. This was a follow-up of previous efforts for the development of a gallium liquid metal slip ring in which the major problem was the formation and ejection of debris. A number of slip ring design approaches were studied. The probe design concept was fully implemented with detail drawings and a model was successfully tested for dielectric strength, shock vibration, acceleration and operation. The conclusions are that a gallium liquid metal slip ring/solar orientation mechanism is feasible and that the problem of debris formation and ejection has been successfully solved.

Weinberger, S. M.↗

NASA NTRS1993

Tumuli and tubes: Teaching scientific techniques

Planetary and space science is the best way to teach basic chemistry, physics, and math. Einstein once said that 'man is drawn to the mysterious and it is from that that we achieve true art and science.' Planets and the processes that shape them are especially mysterious and fascinating to students, young and old, and because of this planetary geology kindles interest that draws them further into the world of science. At the very least, they are engaged enough to learn how science works, a key ingredient in scientific literacy. A project involving field measurements on Kilauea volcano, Hawaii, by a Geology 101 honors class is described. Hawaii is blessed with spectacular, active, accessible, and relatively safe basaltic eruptions. The study of volcanoes, the landforms they produce, and the processes that operate on and in volcanoes, combined with the study of volcanoes on the other planets, is an excellent way to link aspects of Hawaiian geology to the planets. During the past year we have taken advantage of our setting to organize a NASA field workshop for junior investigators and senior graduate students, made field trips and planetary volcanism the centerpieces of our annual Summer Workshop for Teachers, and led a field trip around Kilauea Volcano during the Challenger Center Faculty Development conference, held on the island of Hawaii last summer. An activity for the honors Geology 101 class (all undergraduates) at the University of Hawaii is presently being planned. Our goal is to give them some hands on experience working on a field project and applying what they have learned to planetary volcanoes. The work will include qualitative observations and quantitative measurements on volcanic lava flows. Follow-up activities will involve data analysis. The trip requires planning (at least 3 months before hand) everything from accommodations and insurance to the actual activities we will be doing. Our goal is to stimulate interest and awareness in the students' surroundings, in this case, volcanoes, and to include planetary applications and how studies of terrestrial geology greatly aids studies of the other planets. Two studies are planned both of which are active research projects being conducted by the authors. These projects, tumuli in pahoehoe flow fileds and lava tube cross-secational areas, are described.

Tatsumura, Michelle J.↗

NASA NTRS1972

Aerospace manpower transfer to small business enterprises

The feasibility of a program to effect transfer of aerospace professional people from the ranks of the unemployed into gainful employment in the small business community was investigated. The effectiveness of accomplishing transfer of technology from the aerospace effort into the private sector through migration of people rather than products or hardware alone was also studied. Two basic methodologies were developed. One involves the matching of ex-aerospace professionals and small companies according to their mutual needs. A training and indoctrination program is aimed at familiarizing the professional with the small company environment, and a program of follow-up counseling is defined. The second methodology incorporates efforts to inform and arouse interest among the nonaerospace business community toward affirmative action programs that will serve mutual self-interests of the individuals, companies, and communities involved.

Green, M. K.↗

NASA NTRS1993

Longitudinal study of astronaut health: Mortality in the years 1959-1991

We conducted a historical cohort study of mortality among 195 astronauts who were exposed to space and medical sources of radiation between 1959 and 1991. Cumulative occupational and medical radiation exposures were obtained from the astronaut radiation exposure history data base. Causes of death were obtained from obligatory death certificates and autopsy reports that were on file in the medical records. A total of 18 deaths occurred during the 32-year follow-up period for which the all-cause standardized mortality ratio (SMR) was 142 (95 percent confidence interval 84 225). There was one cancer death in the buccal cavity and pharynegeal ICD-9 rubric whose occurrence was significantly beyond expectation. Mortality for coronary disease was 59 percent lower than expected (2 deaths; SMR = 41; 95 percent confidence limit 5 147). The crude death rate for 10 occupationally related accidents was 400 deaths per 100,000 person-years, which is an order of magnitude greater than accidental death rates in mining industries. The SMR of 1027 for fatal accidents was significantly beyond expectation (14 deaths; 95 percent confidence limit 561 1723) and was similar to SMRs for accidents among aerial pesticide applications. The 10-year cumulative risk of occupational fatalities based on the exponential, Weibull, Gompertz, and linear-exponential distributions was 10 percent. Mortality from motor vehicle accidents was slightly higher than expected but was not significant (1 death; SMR = 145; 95 percent confidence limit 2 808). Radiation exposures from medical procedures accounted for a majority of cumulative dose when compared with space radiation exposures. The results of the study do not confirm the impression that astronauts are at increased risk of cancer, but this does not obviate the need for further study. Overall, it was found that astronauts are at a health disadvantage as a result of catastrophic accidents.

Peterson, Leif E.↗

NASA NTRS1980

Long-term follow-up of Skylab bone demineralization

The os calcis mineral was measured in the nine Skylab crew members and in eight control subjects, 5 years after the Skylab Program, utilizing a photon absorptiometric technique. These measurements were compared with preflight measurements in an attempt to discover any long-term effects of space flight on the skeletal system. A statistically significant loss of bone mineral was found in the crew members who flew, but caution is urged in the interpretation of this difference. A recommendation to continue studies of this type is made.

Tilton, F. E.↗

NASA NTRS1994

Upward appraisal as a means for improving supervisory performance and promoting process improvement, with long-term implications for organizational change

This study represents the implementation phase of an organizational development project which was initiated last year in the Management Support Division (MSD) at Langley Research Center to diagnose organizational functioning. As a result of MSD survey data from last year's effort, a Quality Action Team was created to address the responses compiled from the MSD Organizational Assessment Questionnaire and Follow-Up Questionnaire. The team was officially named the MSD Employee Relations Improvement Team (MERIT). MERIT's goal was to analyze major concerns generated by the questionnaires and to present feasible solutions to management which would improve supervisory performance, promote process improvement; and ultimately, lead to a better organization. The team met weekly and was very disciplined in following guidelines needed to ensure a fully functioning team. Several TQM tools were used during the team process, including brainstorming and the cause and effect diagram. One of the products produced by MERIT was a 'report card', more formally known as an upward appraisal system, to evaluate supervisory performance in the division office, its three branches, and in teams. Major areas of emphasis on the 47 item report card were those identified by employees through the previously administered questionnaires as needing to be improved; specifically, training, recognition, teamwork, supervision and leadership, and communication. MERIT created an enlarged and modified version of the report card which enabled scores for each individual supervisor to be recorded on a separate form, along with summary results and employee comments. Report card results have been compiled and fed back to the Division Chief and Assistant Division Chief. These individuals will in turn, feed the results back to the remaining supervisors and the team leaders. Although results differ among supervisors, some similarities exist. Communication generally appears to be adequate, which represents an improvement over last year. In contrast, recognition and teamwork are the two major areas where improvement in supervisory performance seems to be most needed. The initial report card results will serve as a baseline against which future performance ratings will be compared. Once supervisors have been presented with their data and given an opportunity to analyze and discus the results, they will be assisted in developing an action plan for improving their performance and work processes. They will be provided with ongoing support from management in following through with the action plan.

Siegfeldt, Denise V.↗

NASA NTRS1972

Effects of X-ray irradiation on human spermatogenesis

Direct cell kill and inhibition of mitosis have been suggested as mechanisms to explain the occurrence of absolute sterility following the irradiation of the testes. In order to obtain information on the existence and dose dependency of the mechanisms for man, a controlled study was initiated. Sixty-four men received a single midorgan dose to both of their testes ranging from 7.5 to 400r (f = .95). It was deduced from resulting pre-sterile period and sterile period data that both cell kill and mitosis halting mechanisms were operating. The maximum observed sterile period was 501 days with eventual recovery observed in each individual where the follow-up was complete. Thus man appears to be highly radiosensitive in regard to temporary sterility but quite radioresistant in regard to permanent sterility.

Thorslund, T. W.↗

NASA NTRS1975

Proposed application of lower body negative pressure to cardiology

Potential medical applications are presented of lower body negative pressure to the evaluation and treatment of cardiac patients. The essential features of an LBNP unit and the basic cardiovascular physiology of lower body negative pressure (LBNP) testing are described. Some of the results of previous spaceflight experiences and bedrest studies are summarized. The deconditioning effects of weightlessness experienced by orbiting astronauts are compared with the effects of bedrest restrictions prescribed for convalescing cardiac patients. The potential of LBNP for evaluating both pharmacological and physical activity regimens was examined, particularly in relation to post-myocardial infarction and coronary artery bypass patients. Applications of LBNP to the cardiac catheterization laboratory and the out-patient follow-up of cardiac patients are proposed.

E. V. Schmidt↗

NASA NTRS1988

Electrochemical stability of LiMF6 (M = P, As, Sb) in tetrahydrofuran and sulfolane

The electrochemical stability of LiSbF6 and LiPF6 in aprotic organic solvents has been investigated. Electrochemical studies, conductivity measurements, and open-circuit stability tests were conducted on LiSbF6 in tetrahydrofuran and sulfolane. Cyclic voltammetric studies of SbF6(-) were compared with those of AsF6(-) and PF6(-) anions. Sb(V) was reduced to Sb(III), and then to Sb(0). AsF6(-) was reduced to AsF3, while no reduction of PF6(-) was observed. The reduction products of AsF6(-) and SbF6(-) passivated the glassy carbon electrode, presumably due to LiF precipitation. Peak potentials were observed to shift in the positive direction as a function of concentration. This was accounted for on the basis of a follow-up chemical reaction.

Nanjundiah, C.↗

NASA NTRS1994

An x-ray search for PMS stars in translucent molecular clouds

The work outlined in this paper identifies 108 plausible T Tauri candidates in the regions of two high latitude translucent molecular clouds. Follow-up optical spectroscopy of these candidates is needed to resolve the question of whether or not star formation is present in these clouds. We have recently submitted a proposal to use the Kitt Peak National Observatory 2.1 meter telescope to take medium resolution spectra of the 14 PMS candidate X-ray sources in MBM 40 to determine spectral types and search for indicators of youth (strong Li absorption; H alpha emission) and we will submit a similar proposal to study the X-ray sources in MBM 55. Only spectra will provide an unambiguous determination of their pedigree. As part of an ongoing study of star formation at high galactic latitude we intend to analyze data in the ROSAT archives to investigate the possibility of star formation in all of the high latitude translucent molecular clouds observed. We believe that this project may yield a significant increase in our understanding of the star formation process for low-mass stars and of the nature of the translucent clouds.

Caillault, Jean-Pierre↗

NASA NTRS1992

Taguchi methods in electronics: A case study

Total Quality Management (TQM) is becoming more important as a way to improve productivity. One of the technical aspects of TQM is a system called the Taguchi method. This is an optimization method that, with a few precautions, can reduce test effort by an order of magnitude over conventional techniques. The Taguchi method is specifically designed to minimize a product's sensitivity to uncontrollable system disturbances such as aging, temperature, voltage variations, etc., by simultaneously varying both design and disturbance parameters. The analysis produces an optimum set of design parameters. A 3-day class on the Taguchi method was held at the Marshall Space Flight Center (MSFC) in May 1991. A project was needed as a follow-up after the class was over, and the motor controller was selected at that time. Exactly how to proceed was the subject of discussion for some months. It was not clear exactly what to measure, and design kept getting mixed with optimization. There was even some discussion about why the Taguchi method should be used at all.

Kissel, R.↗

NASA NTRS1977

Application of airborne infrared technology to monitor building heat loss

The application of airborne infrared technology to the requirements for energy conservation in buildings was studied. Quantitative airborne data of the City of Ypsilanti, Michigan, were collected and processed to identify roof temperatures. A thermal scanner was flown at an altitude of 1,200 feet with two thermal bands 8.2-9.3 micrometers and 10.4-12.5 micrometers recorded by an analog system. Calibration was achieved by standard hot and cold plates. Using a thermal model to interpret ceiling insulation status, environmental factors were found to influence the relation between roof temperature and insulation. These include interior and sky temperatures, roofing materials, and the pitch and orientation of the roof. A follow-up mail survey established the ability to identify insulated and uninsulated houses from the airborne infrared data.

Tanis, F. J.↗

NASA NTRS1993

Multiwavelength observations of unidentified high energy gamma ray sources

As was the case for COS B, the majority of high-energy (greater than 100 MeV) gamma-ray sources detected by the EGRET instrument on GRO are not immediately identifiable with cataloged objects at other wavelengths. These persistent gamma-ray sources are, next to the gamma-ray bursts, the least understood objects in the universe. Even a rudimentary understanding of their nature awaits identifications and follow-up work at other wavelengths to tell us what they are. The as yet unidentified sources are potentially the most interesting, since they may represent unrecognized new classes of astronomical objects, such as radio-quiet pulsars or new types of active galactic nuclei (AGN's). This two-year investigation is intended to support the analysis, correlation, and theoretical interpretation of data that we are obtaining at x ray, optical, and radio wavelengths in order to render the gamma-ray data interpretable. According to plan, in the first year concentration was on the identification and study of Geminga. The second year will be devoted to studies of similar unidentified gamma-ray sources which will become available in the first EGRET catalogs. The results obtained so far are presented in the two papers which are reproduced in the Appendix. In these papers, we discuss the pulse profiles of Geminga, the geometry and efficiency of the magnetospheric accelerator, the distance to Geminga, the implications for theories of polar cap heating, the effect of the magnetic field on the surface emission and environment of the neutron star, and possible interpretations of a radio-quiet Geminga. The implications of the other gamma-ray pulsars which were discovered to have high gamma-ray efficiency are also discussed, and the remaining unidentified COS B sources are attributed to a population of efficient gamma-ray sources, some of which may be radio quiet.

Halpern, Jules P.↗

NASA NTRS1992

FNAS/solar flare energetics

We have performed an extensive study of solar flare energy buildup and release, concentrating in two aspects: (1) relationship with 3D field topology and measured electric currents; and (2) flare onset characteristics as determined from combined x ray and ultraviolet observations. We extended our previous studies on the characteristic topology of flaring regions, by following the evolution of an active region over three consecutive days. From comparison with flare observations in x rays and h alpha, we found further support for the hypothesis that flares were triggered by taking place at the separators (3D generalization of and x-type neutral point). Furthermore, we found that emerging in flux at a site within the active regions where no (or little) activity was previously observed, caused the appearance of a secondary separator and thereon continuous triggering of activity at such site. Our topology arguments were then applied to a study of sympathetic activity between two regions within an active complex. Here again we found that interacting field structures along separators and separatrices, which act as pathways for recurrent flaring to spread between the regions, could be used to understand how activity spread to potentially explosive sites with the complex. We also finished our study of flare onset characteristics as determined from combined x ray and ultraviolet observations. Using a quasi-static modeling approach, we find that this phase is characterized by a relatively low level of energy release, 10 exp 26-27 erg/s, which is sufficient to produce 'gentle' evaporation, a shift in the location of the transition zone as compared to pre-flare conditions, and an increase in the temperature and density of coronal loops. All these changes have profound implications on the observed signatures of impulsive phase phenomena, which had been neglected in the past. As a follow-up of this investigation, we now plan to apply our results to the interpretation of high-sensitivity spectroscopic and hard x-ray data currently being gathered by the Yohkoh and Compton Gamma Ray Observatory satellites.

Machado, M. E.↗

NASA NTRS1988

Cardiovascular effects of weightlessness and ground-based simulation

A large number of animal and human flight and ground-based studies were conducted to uncover the cardiovascular effects of weightlessness. Findings indicate changes in cardiovascular function during simulations and with spaceflight that lead to compromised function on reambulation and/or return to earth. This altered state termed cardiovascular deconditioning is most clearly manifest when in an erect body state. Hemodynamic parameters inidicate the presence of excessive tachnycardia, hypotension (leading to presyncope in one-third of the subjects), decreased heart volume, decreased plasma and circulating blood volumes and loss of skeletal muscle mass, particularly in the lower limbs. No clinically harmful effects were observed to date, but in-depth follow-ups were limited, as was available physiologic information. Available data concerning the causes for the observed changes indicate significant roles for mechanisms involved with body fluid-volume regulation, altered cardiac function, and the neurohumoral control of the control of the peripheral circulation. Satisfactory measures are not found. Return to preflight state was variable and only slightly dependent on flight duration. Future progress awaits availability of flight durations longer than several weeks.

Sandler, Harold↗

NASA NTRS1987

Rocket experiments and payloads for Super CAMP

The super Cold Arctic Mesopause Project (CAMP) follow-up project in the summer of 1990 is outlined. In situ measurements of appropriate height resolution are needed in the summer mesosphere at high latitudes to investigate structures and formation processes of polar mesospheric clouds. The rocket measurements from the high latitude site Thule AB in Greenland (76.6 N) are decisive for the understanding of the cold Arctic mesopause. Similar rocket measurements from the European ranges Andenes and Esrange (68 to 69 N) are needed to investigate the latitudinal variability of the parameters relevant for the formation, transport, and loss of mesospheric ice particles. An important aspect of Super CAMP is the study of the heterogeneous chemistry, the loss of electrons on aggregates, and the build-up of horizontal and vertical electric fields in the presence of charged ice particles. Instruments, measurements, and purpose are listed.

Kopp, E.↗

NASA NTRS1973

Technical feasibility study for the development of a large capacity wind powered electrical generating system

The engineering feasibility of developing a basic mechanical system necessary for extracting large amounts of power (on the order of 10 to 20 MW) from the wind is considered using the concept of vertical airfoils moving along a closed horizontal track system. Attention is focused on those components necessary for the conversion of wind energy to mechanical energy, although the general characteristics and critical aspects of other components are also considered. The four phases of this program are: (1) Establishment of component specifications and interface requirements for major system components; (2) formulation of alternative sets of conceptual designs for major system components; (3) engineering analysis of various components and systems; and (4) re-examination of basic concept and identification of any desirable follow-up work.

Powe, R. E.↗

NASA NTRS1989

A study of the effects of disk flexibility on the rotordynamics of the space shuttle main engine turbo-pumps

Rotor dynamical analyses are typically performed using rigid disk models. Studies of rotor models in which the effects of disk flexibility were included indicate that is may be an important effect for many systems. This issue is addressed with respect to the Space Shuttle Main Engine high pressure turbo-pumps. Finite element analyses have been performed for a simplified free-free flexible disk rotor model and the modes and frequencies compared to those of a rigid disk model. The simple model was then extended to a more sophisticated HPTOP rotor model and similar results were observed. Equations were developed that are suitable for modifying the current rotordynamical analysis program to account for disk flexibility. Some conclusions are drawn from the results of this work as to the importance of disk flexibility on the HPTOP rotordynamics and some recommendations are given for follow-up research in this area.

Flowers, George T.↗