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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

IMAGE EUV Observation of a Radially, Bifurcated Plasmapause: First Observations of a Possible Standing ULF Waveform in the Inner Magnetosphere

We present EUV observations of the plasmasphere-plasmapause from 19:38-22:11 UT on 28 June 2000 characterized by the presence of bifurcated radial enhancements of the He(+) plasma distribution in the nighside sector. These features remain stable throughout the period of observation and are found to co-rotate at 67% of the expected rate. Two-dimensional simulation of the plasmasphere assuming the presence of field lines resonances at L = 1.8 and 2.5 suggest that the organization of the outer plasmasphere and plasmapause is the result convective motion driven by a standing ULF-wave. Preliminary analysis of ground-based magnetometer data provided by the IMAGE magnetometer network during the period of EUV observation indicates the presence of a discrete spectrum of field line resonances extending down to 0.68-mHz.

Adrian, M. L.↗
NASA NTRS2003

Strength, Fracture Toughness, Fatigue, and Standardization Issues of Free-standing Thermal Barrier Coatings

Strength, fracture toughness and fatigue behavior of free-standing thick thermal barrier coatings of plasma-sprayed ZrO2-8wt % Y2O3 were determined at ambient and elevated temperatures in an attempt to establish a database for design. Strength, in conjunction with deformation (stress-strain behavior), was evaluated in tension (uniaxial and trans-thickness), compression, and uniaxial and biaxial flexure; fracture toughness was determined in various load conditions including mode I, mode II, and mixed modes I and II; fatigue or slow crack growth behavior was estimated in cyclic tension and dynamic flexure loading. Effect of sintering was quantified through approaches using strength, fracture toughness, and modulus (constitutive relations) measurements. Standardization issues on test methodology also was presented with a special regard to material's unique constitutive relations.

Choi, Sung R.↗
NASA NTRS2003

In-Space Propulsion: Where We Stand and What's Next

The focus of this paper will be on the three stages of in-space transportation propulsion systems, now commonly referred to as in-space propulsion (ISP); i.e., the transfer of payloads from low-Earth orbits into higher orbits or into trajectories for planetary encounters, including planetary landers and sample return launchers, if required. Functions required at the operational location where ISP must provide thrust for orbit include maintenance, position control, stationkeeping, and spacecraft altitude control; i.e., proper pointing and dynamic stability in inertial space; and the third function set to enable operations at various planetary locations, such as atmospheric entry and capture, descent to the surface and ascent, back to rendezvous orbit. The discussion will concentrate on where ISP stands today and some observations of what might be next in line for new ISP technologies and systems for near-term and future flight applications. The architectural choices that are applicable for ISP will also be described and discussed in detail.

Sackheim, Robert L.↗
NASA NTRS1999

Effects of standing on cerebrovascular resistance in patients with idiopathic orthostatic intolerance

PURPOSE: Patients with idiopathic orthostatic intolerance often have debilitating symptoms on standing that are suggestive of cerebral hypoperfusion despite the absence of orthostatic hypotension. SUBJECTS AND METHODS: We evaluated the effects of graded head-up tilt on cerebral blood flow as determined by transcranial Doppler measurements in 10 patients with idiopathic orthostatic intolerance (nine women, one man, 22 to 47 years) and nine age- and sex-matched control subjects. RESULTS: In patients, mean (+/- SD) arterial pressure at 0 degrees head-up tilt was 90 +/- 11 mm Hg and was well maintained at all tilt angles (90 +/- 11 mm Hg at 75 degrees). In controls, mean arterial pressure was 85 +/- 7 mm Hg at 0 degrees and 82 +/- 11 mm Hg at 75 degrees head-up tilt. There was a substantial decrease in peak velocity with increasing tilt angle in patients (28% +/- 10%) but not in controls (10% +/- 10% at 75 degrees, P <0.001). Similarly, mean velocity decreased 26% +/- 13% in patients and 12% +/- 11% in controls (P = 0.01). With increasing head-up tilt, patients had a significantly greater increase in regional cerebrovascular resistance than controls. CONCLUSIONS: In patients with idiopathic orthostatic intolerance, peak and mean middle cerebral artery blood flow velocity decreased in response to head-up tilt despite well sustained arterial blood pressure. These observations indicate that in this group of patients, regulation of cerebrovascular tone may be impaired and might therefore be a target for therapeutic interventions.

Non-NASA Center↗
NASA NTRS2005

Why do Some Dwarf Novae Stand Still?

The papers published through support of NASA. "Why do Some DwarfNovae Stand Still?" Preliminary results were published in the form of an abstract as part of Joint Discussion 5, at the IAU meeting in Sydney. The complete reference is: Hartley, L. E., Long, K. S., Froning, C.-S., & Drew, J. E. 2003, "The White Dwarf and Accretion Stream in Z Cam", presented as part of Joint Discussion 5, "White Dwarfs: Galactic and Cosmologic Probes, at 25th meeting of the MU, Joint Discussion 5 , 16-17 July 2003, Sydney, Australia Our final results were published in the Astrophysical Journal this year. Hartley, L. E., Long, K. S., Froning, C. S., & Drew, J. E. 2005, "The Far-Ultraviolet Spectrum of Z Camelopardalis in Quiescence and Standstill", ApJ, 623,425.

Sonneborn, George↗
NASA NTRS2002

Evolving circuits in seconds: experiments with a stand-alone board-level evolvable system

The purpose of this paper is twofold: first, to illustrate a stand-alone board-level evolvable system (SABLES) and its performance, and second to illustrate some problems that occur during evolution with real hardware in the loop, or when the intention of the user is not completely reflected in the fitness function.

evolvable hardware FPTA DSP evolutionary algorithm↗
NASA NTRS1994

Stand-alone digital data storage control system including user control interface

A storage control system includes an apparatus and method for user control of a storage interface to operate a storage medium to store data obtained by a real-time data acquisition system. Digital data received in serial format from the data acquisition system is first converted to a parallel format and then provided to the storage interface. The operation of the storage interface is controlled in accordance with instructions based on user control input from a user. Also, a user status output is displayed in accordance with storage data obtained from the storage interface. By allowing the user to control and monitor the operation of the storage interface, a stand-alone, user-controllable data storage system is provided for storing the digital data obtained by a real-time data acquisition system.

Wright, Kenneth D.↗
NASA NTRS2009

Comparison of Computerized Sway Referencing and Standing on a Compliant Surface

Background: By removing vision and altering somatosensory inputs, we can examine the contributions of the vestibular system on balance control. Computerized Dynamic Posturography (CDP) systems accomplish this by using a dynamic plate that moves in proportion to the sway of the subject. A potential alternative to CDP is the use of a compliant foam surface. The goal of this study was to compare postural sway during each condition. Methods: Thirty-two healthy subjects (16 male and 16 female) were tested on a Equitest computerized posturography system and on a 5 inch thick block of foam (NeuroCom International; Clackamas, OR). Subjects performed three trials with their head erect and five trials with dynamic head tilts ( 20 at 0.33Hz) in the anterior-posterior (AP) plane. Subjects were instructed to stand quietly with their arms folded and eyes closed for each trial lasting 20 seconds. The sway in both AP and medial-lateral (ML) planes was calculated for each trial, as well as the total sway path length. Results: In general, AP sway tended to be greater on the Equitest than on foam and greater during the head movement trials than the head erect. The ML sway was consistently higher on foam and did not vary between head erect and moving conditions. Sway path length was consistently greater for head erect trials on foam and tended to be greater for head movement trials on the Equitest. The addition of head movements increases AP sway and the total path length. Conclusions: Based on the increase of sway in the ML direction, it is important to quantify sway in all directions when on a compliant foam surface.

Dean, S. Lance↗
NASA NTRS2006

Fabrication and Characteristics of Free Standing Shaped Pupil Masks for TPF-Coronagraph

Direct imaging and characterization of exo-solar terrestrial planets require coronagraphic instruments capable of suppressing star light to 10-10. Pupil shaping masks have been proposed and designed1 at Princeton University to accomplish such a goal. Based on Princeton designs, free standing (without a substrate) silicon masks have been fabricated with lithographic and deep etching techniques. In this paper, we discuss the fabrication of such masks and present their physical and optical characteristics in relevance to their performance over the visible to near IR bandwidth.

terrestrial planet finder↗
NASA NTRS1951

Control Performance of General Electric Fuel and Torque Regulator Operating on T31-3 Turbine-Propeller Engine in Sea-Level Test Stand

A .General Electric fuel and torque regulator was tested in conjunction with a T31-3 turbine-propeller engine in the sea-level static test stand at the NACA Lewis laboratory. The engine and control were operated over the entire speed range: 11,000 rpm, nominal flight idle, to 13,000 rpm, full power. Steady-state and transient data were recorded and are presented with a description of the four control loops being used in the system. Results of this investigation indicated that single-lever control operation was satisfactory under conditions of test. Transient data presented showed that turbine-outlet temperature did overshoot maximum operating value on acceleration but that the time duration of overshoot did not exceed approximately 1 second. This temperature limiting resulted from a control on fuel flow as a function of engine speed. Speed and torque first reached their desired values 0.4 second from the time of change in power-setting lever position. Maximum speed overshoot was 3 percent.

Oppenheimer, Frank L.↗
NASA NTRS2009

Human Research Program Human Health Countermeasures Element Sensorimotor Risk Standing Review Panel (SRP) Final Report

The Sensorimotor Risk Standing Review Panel (SRP) met at the NASA Johnson Space Center on October 4-6, 2009 to discuss the areas of future research targeted by the Human Health Countermeasures (HHC) Element of the Human Research Program (HRP). Using evidence-based knowledge as a background for risks, NASA had identified gaps in knowledge to address those risks. Ongoing and proposed tasks were presented to address the gaps. The charge to the Sensorimotor Risk SRP was to review the gaps, evaluate whether the tasks addressed these gaps and to make recommendations to NASA s HRP Science Management Office regarding the SRP's review. The SRP was requested to evaluate the practicality of the proposed efforts in light of the realistic demands placed on the HRP. In short, all tasks presented in the Integrated Research Plan (IRP) should address specific risks related to the challenges faced by the astronauts as a result of prolonged exposure to microgravity. All tasks proposed to fill the gaps in knowledge should provide applied, translational data necessary to address the specific risks. Several presentations were made to the SRP during the site visit and the SRP spent sufficient time to address the panel charge, either as a group or in separate sessions. The SRP made a final debriefing to the HRP Program Scientist. Taking the evidence and the risk as givens, the SRP reached the following conclusions: 1) the panel is very supportive of and endorses the present activities of the Sensorimotor Risk; and the panel is likewise supportive of the gaps and associated tasks in the IRP; 2) overall, the tasks addressed the gaps in the IRP; 3) there were some gaps and tasks that merit further enhancement and some new gaps/tasks that the SRP recommends.

Peterson, Barry↗
NASA NTRS2009

Human Research Program Human Health Countermeasures Element Nutrition Risk Standing Review Panel

The Nutrition Risk Standing Review Panel (SRP) reviewed and discussed the specific gaps and tasks for the Human Health Countermeasures (HHC) Element related to nutrition identified in the Human Research Program (HRP) Integrated Research Plan. There was general consensus that the described gaps and proposed tasks were critical to future NASA mission success. The SRP acknowledged the high scientific quality of the work currently being undertaken by the Nutritional Biochemistry group under the direction of Dr. Scott Smith. In review of the entire HRP, four new gaps were identified that complement the Element's existing research activities. Given the limitations of ground-based analogs for many of the unique physiological and metabolic alterations in space, future studies are needed to quantify nutritional factors that change during actual space flight. In addition, future tasks should seek to better evaluate the time course of physiological and metabolic alterations during flight to better predict alterations during longer duration missions. Finally, given the recent data suggesting a potential role for increased inflammatory responses during space flight, the role of inflammation needs to be explored in detail, including the development of potential countermeasures and new ground based analogs, if this possibility is confirmed.

Bistrian, Bruce↗
NASA NTRS2009

Human Research Program Human Health Countermeasures Element Bone and Muscle Risk Standing Review Panel (SRP)

The Bone and Muscle Risk Standing Review Panel (SRP) met at the NASA Johnson Space Center (JSC) on October 4-6, 2009 to discuss the areas of current and future research targeted by the Human Health Countermeasures (HHC) Element of the Human Research Program (HRP). Using evidence-based knowledge as a background for identified risks to astronaut health and performance, NASA had identified gaps in knowledge to address those risks. Ongoing and proposed tasks were presented to address the gaps. The charge to the Bone and Muscle Risk SRP was to review the gaps, evaluate whether the tasks addressed these gaps and to make recommendations to NASA s HRP Science Management Office regarding the Panel's review. The Bone and Muscle Risk SRP consisted of scientists who are experts in muscle, bone, or both and could evaluate the existing evidence with sufficient knowledge of the potential effects of long duration exposure to microgravity. More important, although expertise in basic science is important, the SRP was requested to evaluate the practicality of the proposed efforts in light of the realistic demands placed on the HRP. In short, all tasks presented in the Integrated Research Plan (IRP) should address specific questions related to the challenges faced by the astronauts as a result of prolonged exposure to microgravity. All tasks proposed to fill the gaps in knowledge should provide applied, translational data necessary to answer the specific questions. Several presentations were made to the SRP during the site visit and the SRP spent sufficient time to address the panel charge, either as a group or in separate sessions for the Bone and Muscle Risk subgroups. The SRP made a final debriefing to the HRP Program Scientist, Dr. John B. Charles, on October 6, 2009. Taking the evidence and identified risks as givens, the SRP concluded that 1) integration of information should lead to a more comprehensive approach to identifying the gaps, 2) not all tasks addressed the gaps as stated in the IRP, 3) better access should be given to the SRP to existing data to include in its review, and 4) there were some missing gaps and tasks. As a result the SRP recommended 1) combining certain gaps, which in some cases were addressed with identical tasks, 2) additional gaps and tasks to address some of the gaps, 3) deleting some gaps and tasks to better focus the efforts of NASA s HRP in prioritizing their efforts, and 4) prioritizing gaps to address significant issues needing resolution in the short term while maintaining an awareness of long-term goals. The SRP commended the efforts by the HHC Element to integrate knowledge gaps and design tasks to address the higher order questions. This integration did not apply to the Bone and Muscle Risk alone, but the musculoskeletal system as its functions integrate with issues in

Glowacki, Julie↗
NASA NTRS2009

Human Research Program Human Health Countermeasures Element Cardiovascular Risks Standing Review Panel (SRP)

The Cardiovascular Risk Standing Review Panel (SRP) evaluated several cardiovascular risks associated with space flight along with the ongoing and emerging plans to study these issues and potentially propose and/or develop countermeasures. The areas of focus included: 1) The risk of cardiac rhythm problems during prolonged space flight, and 2) Issues related to the risk of orthostatic intolerance during re-exposure to gravity. An emerging area of concern is radiation associated vascular injury. The risk of cardiac rhythm disturbances has emerged based on case reports only. No systematic study of this risk has been published. However, concerns about this risk are heightened by the age range of astronauts, the structural changes in the heart that occur during space flight, and the potential shifts in fluids and electrolytes. The current plan is to use prolonged Holter monitor EKG records made as part of the "Integrated Cardiovascular SMO" in space to determine more about the frequency and magnitude of this problem and to link this data to complementary data from the nutrition group on electrolytes. The SRP was supportive of this approach. The SRP also felt that any data related to cardiovascular risk in space should be better coordinated with the medical screening data that all astronauts undergo at regular intervals. Additionally, while there are potential privacy issues related to this suggestion, many of the current barriers to better coordination of experimental and clinical data appear to reflect longstanding cultural traditions at NASA that need rethinking. The risk of orthostatic intolerance during re-exposure to gravity was seen by the SRP as an area supported by a wealth of published physiological evidence. The SRP also felt that moving forward with the planned approach to countermeasures was reasonable and that extensive additional hypothesis testing on the physiology of orthostatic intolerance was not needed at this time. There was support for developing ground based models of limited (e.g. 1/6 th) G environments on Earth that generated a number of ideas for consideration by NASA investigators.

Joyner, Michael↗
NASA NTRS2010

Behavioral Health and Performance (BHP) Standing Review Panel (SRP) Final Report

The first meeting of the Behavioral Health and Performance (BHP) Standing Review Panel (SRP) was held in Houston, TX on November 1-3, 2009. Our task was to assess the Integrated Research Plan (IRP) related to the fields covered in the SRP charge (see section VIII). Having considered and discussed the extensive materials distributed prior to the meeting, and the highly informative briefings by the NASA BHP Human Research Program (HRP) personnel during the site visit, the SRP agreed that the IRP is comprehensive and was developed carefully. Question and answer periods with the presenters were particularly productive and helpful to the SRP. The presenters' willingness to share information and positive responses to the SRP's suggestions were greatly appreciated. Although the IRP and related documents are impressive, the SRP does have a number of recommendations regarding both the overall plan and its component parts.

Suedfeld, Peter↗
NASA NTRS2009

Human Research Program Human Health Countermeasures Element Extravehicular Activity (EVA) Risk Standing Review Panel (SRP)

The Extravehicular Activity (EVA) Risk Standing Review Panel (SRP) was favorably impressed by the operational risk management approach taken by the Human Research Program (HRP) Integrated Research Plan (IRP) to address the stated life sciences issues. The life sciences community at the Johnson Space Center (JSC) seems to be focused on operational risk management. This approach is more likely to provide risk managers with the information they need at the time they need it. Concerning the information provided to the SRP by the EVA Physiology, Systems, and Performance Project (EPSP), it is obvious that a great deal of productive activity is under way. Evaluation of this information was hampered by the fact that it often was not organized in a fashion that reflects the "Gaps and Tasks" approach of the overall Human Health Countermeasures (HHC) effort, and that a substantial proportion of the briefing concerned subjects that, while interesting, are not part of the HHC Element (e.g., the pressurized rover presentation). Additionally, no information was provided on several of the tasks or how they related to work underway or already accomplished. This situation left the SRP having to guess at the efforts and relationship to other elements, and made it hard to easily map the EVA Project efforts currently underway, and the data collected thus far, to the gaps and tasks in the IRP. It seems that integration of the EPSP project into the HHC Element could be improved. Along these lines, we were concerned that our SRP was split off from the other participating SRPs at an early stage in the overall agenda for the meeting. In reality, the concerns of EPSP and other projects share much common ground. For example, the commonality of the concerns of the EVA and exercise physiology groups is obvious, both in terms of what reduced exercise capacity can do to EVA capability, and how the exercise performed during an EVA could contribute to an overall exercise countermeasure prescription.

Norfleet, William↗