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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Validation of the F-18 high alpha research vehicle flight control and avionics systems modifications

The verification and validation process is a critical portion of the development of a flight system. Verification, the steps taken to assure the system meets the design specification, has become a reasonably understood and straightforward process. Validation is the method used to ensure that the system design meets the needs of the project. As systems become more integrated and more critical in their functions, the validation process becomes more complex and important. The tests, tools, and techniques which are being used for the validation of the high alpha research vehicle (HARV) turning vane control system (TVCS) are discussed and the problems and their solutions are documented. The emphasis of this paper is on the validation of integrated system.

Chacon, Vince↗
NASA NTRS1991

Contributions to the implementation of the Arakawa-Schubert cumulus parameterization in the GLA GCM

The roles of the Critical Cloud Work Function (CCWF) data set and the upper and lower bounds on entrainment by cumulus plumes in the Arakawa-Schubert cumulus parameterization (ASCP) in the GLA GCM (Geller et al., 1988) were investigated in two sets of experiments. It was found that the horizontal and vertical distribution of cumulus heating can be altered in ASCP by adjusting these parameters. These changes can have a strong influence on the vertical structure of condensation heating, water vapor distribution, temperature, and rainfall. The CCWF is an important limiting parameter that controls the onset of different cloud types; increasing the threshold values of CCWF for all clouds tends to concentrate the rainfall into a narrower ITCZ and affects the rainfall during the initial adjustment period.

Sud, Y. C.↗
NASA NTRS1990

Validation of the F-18 high alpha research vehicle flight control and avionics systems modifications

The verification and validation process is a critical portion of the development of a flight system. Verification, the steps taken to assure the system meets the design specification, has become a reasonably understood and straightforward process. Validation is the method used to ensure that the system design meets the needs of the project. As systems become more integrated and more critical in their functions, the validation process becomes more complex and important. The tests, tools, and techniques which are being used for the validation of the high alpha research vehicle (HARV) turning valve control system (TVCS) are discussed, and their solutions are documented. The emphasis of this paper is on the validation of integrated systems.

Chacon, Vince↗
NASA NTRS1993

ACE: A distributed system to manage large data archives

Competitive pressures in the oil and gas industry are requiring a much tighter integration of technical data into E and P business processes. The development of new systems to accommodate this business need must comprehend the significant numbers of large, complex data objects which the industry generates. The life cycle of the data objects is a four phase progression from data acquisition, to data processing, through data interpretation, and ending finally with data archival. In order to implement a cost effect system which provides an efficient conversion from data to information and allows effective use of this information, an organization must consider the technical data management requirements in all four phases. A set of technical issues which may differ in each phase must be addressed to insure an overall successful development strategy. The technical issues include standardized data formats and media for data acquisition, data management during processing, plus networks, applications software, and GUI's for interpretation of the processed data. Mass storage hardware and software is required to provide cost effective storage and retrieval during the latter three stages as well as long term archival. Mobil Oil Corporation's Exploration and Producing Technical Center (MEPTEC) has addressed the technical and cost issues of designing, building, and implementing an Advanced Computing Environment (ACE) to support the petroleum E and P function, which is critical to the corporation's continued success. Mobile views ACE as a cost effective solution which can give Mobile a competitive edge as well as a viable technical solution.

Daily, Mike I.↗
NASA NTRS2000

Separating the from the Imagined: Flight Research at the NACA and NASA, 1915-1998

One of the most important, but under-appreciated, aspects of the NACA/NASA mission is its aeronautical R&D efforts. Within a short time of the first flight of the Wright brothers in 1903, the United States government recognized the importance of fostering development in the new and critical field of aeronautics. NASA's predecessor, the National Advisory Committee for Aeronautics (NACA), was chartered by Congress in 1915 specifically "to supervise and direct the scientific study of the problems of flight, with a view to their practical solution. " This became an enormously important government research and development activity for the next half century, materially enhancing the development of aeronautics 'in America. The results of the NACA's research appeared in more than 16,000 research reports of one type or another, distributed widely for the benefit of all. Many of the reports documenting R&D conducted under NACA auspices are still being used today. Since the creation of NASA in 1958, the critical R&D function has continued but is not well known. This work documents the historical R&D program of the agency by focusing on flight research.

Gorn, Michael H.↗
NASA NTRS2001

Monolithic THz Frequency Multipliers

Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.

Erickson, N. R.↗
NASA NTRS1997

Callosally projecting neurons in the macaque monkey V1/V2 border are enriched in nonphosphorylated neurofilament protein

Previous immunohistochemical studies combined with retrograde tracing in macaque monkeys have demonstrated that corticocortical projections can be differentiated by their content of neurofilament protein. The present study analyzed the distribution of nonphosphorylated neurofilament protein in callosally projecting neurons located at the V1/V2 border. All of the retrogradely labeled neurons were located in layer III at the V1/V2 border and at an immediately adjacent zone of area V2. A quantitative analysis showed that the vast majority (almost 95%) of these interhemispheric projection neurons contain neurofilament protein immunoreactivity. This observation differs from data obtained in other sets of callosal connections, including homotypical interhemispheric projections in the prefrontal, temporal, and parietal association cortices, that were found to contain uniformly low proportions of neurofilament protein-immunoreactive neurons. Comparably, highly variable proportions of neurofilament protein-containing neurons have been reported in intrahemispheric corticocortical pathways, including feedforward and feedback visual connections. These results indicate that neurofilament protein is a prominent neurochemical feature that identifies a particular population of interhemispheric projection neurons at the V1/V2 border and suggest that this biochemical attribute may be critical for the function of this subset of callosal neurons.

Non-NASA Center↗
NASA NTRS1995

Hydroxycinnamic acid-derived polymers constitute the polyaromatic domain of suberin

Suberin is an abundant, complex, intractable, plant cell wall polymeric network that forms both protective and wound-healing layers. Its function is, therefore, critical to the survival of all vascular plants. Its chemical structure and biosynthesis are poorly defined, although it is known to consist of both aromatic and aliphatic domains. While the composition of the aliphatic component has been fairly well characterized, that of the phenolic component has not. Using a combination of specific carbon-13 labeling techniques, and in situ solid state 13C NMR spectroscopic analysis, we now provide the first direct evidence for the nature of the phenolic domain of suberin and report here that it is almost exclusively comprised of a covalently linked, hydroxycinnamic acid-derived polymeric matrix.

NASA Discipline Plant Biology↗
NASA NTRS1994

Results of a Formal Methods Demonstration Project

This paper describes the results of a cooperative study conducted by a team of researchers in formal methods at three NASA Centers to demonstrate FM techniques and to tailor them to critical NASA software systems. This pilot project applied FM to an existing critical software subsystem, the Shuttle's Jet Select subsystem (Phase I of an ongoing study). The present study shows that FM can be used successfully to uncover hidden issues in a highly critical and mature Functional Subsystem Software Requirements (FSSR) specification which are very difficult to discover by traditional means.

formal methods computer system specification compu↗
NASA NTRS2006

Validation (not just verification) of Deep Space Missions

ion & Validation (V&V) is a widely recognized and critical systems engineering function. However, the often used definition 'Verification proves the design is right; validation proves it is the right design' is rather vague. And while Verification is a reasonably well standardized systems engineering process, Validation is a far more abstract concept and the rigor and scope applied to it varies widely between organizations and individuals. This is reflected in the findings in recent Mishap Reports for several NASA missions, in which shortfalls in Validation (not just Verification) were cited as root- or contributing-factors in catastrophic mission loss. Furthermore, although there is strong agreement in the community that Test is the preferred method for V&V, many people equate 'V&V' with 'Test', such that Analysis and Modeling aren't given comparable attention. Another strong motivator is a realization that the rapid growth in complexity of deep-space missions (particularly Planetary Landers and Space Observatories given their inherent unknowns) is placing greater demands on systems engineers to 'get it right' with Validation.

verification↗
NASA NTRS2010

Effects of Short- and Long-Duration Space Flight on Neuromuscular Function

The Functional Task Tests (FTT) is an interdisciplinary study designed to correlate the changes in functional tasks (such as emergency egress, ladder climbing, and hatch opening) with changes in neuromuscular, cardiovascular, and sensorimotor function. One aspect of the FTT, the neuromuscular function test, is used to investigate the neuromuscular component underlying changes in the ability of astronauts to perform functional tasks (representative of critical mission tasks) safely and quickly after flight. PURPOSE: To describe neuromuscular function after short- and long-duration space flight. METHODS: To date, 5 crewmembers on short-duration (10- to 15-day) missions and 3 on long-duration missions have participated. Crewmembers were assessed 30 days before flight, on landing day (short-duration subjects only) and 1, 6, and 30 days after landing. The interpolated twitch technique, which utilizes a combination of maximal voluntary contractions and electrically evoked contractions, was used to assess the maximal voluntary isometric force (MIF) and central activation capacity of the knee extensors. Leg-press and bench-press devices were used to assess MIF and maximal dynamic power of the lower and upper body respectively. Specifically, power was measured during concentric-only ballistic throws of the leg-press sled and bench-press bar loaded to 40% and 30% of MIF respectively. RESULTS: Data are currently being collected from both Shuttle and ISS crewmembers. Emerging data indicate that measures of knee extensor muscle function are decreased with long-duration flight. DISCUSSION: The relationships between flight duration, neural drive, and muscle performance are of particular interest. Ongoing research will add to the current sample size and will focus on defining changes in muscle performance measures after long-duration space flight.

Buxton, Roxanne E.↗
NASA NTRS2013

Individual Differences in the Temporal Profile of Cardiovascular Responses to Head Down Tilt and Orthostatic Stress with and Without Fluid Loading

Susceptibility of healthy astronauts to orthostatic hypotension and presyncope is exacerbated upon return from spaceflight. Hypo-volemia is suspected to play an important role in cardiovascular deconditioning following exposure to spaceflight, which may lead to increased peripheral resistance, attenuated arterial baroreflex, and changes in cardiac function. The effect of altered gravity during space flight and planetary transition on human cardiovascular function is of critical importance to maintenance of astronaut health and safety. A promising countermeasure for post-flight orthostatic intolerance is fluid loading used to restore loss fluid volume by giving crew salt tablets and water prior to re-entry. Eight men and eight women will be tested during two, 6-hour exposures to 6o HDT: 1) fluid loading, 2) no fluid loading. Before and immediately after each HDT, subjects will perform a stand test to assess their orthostatic tolerance. Physiological measures (e.g., ECG, blood pressure, peripheral blood volume) will be continuously monitored while echocardiography measures are recorded at 30-minute intervals during HDT and stand tests. Preliminary results (N=4) clearly show individual differences in responses to this countermeasure and the time course of physiological changes induced by HDT.

Cowings, Patricia↗
NASA NTRS2016

The "Puck" Energetic Charged Particle Detector: Design, Heritage, and Advancements

Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of approximately 10 kiloelectronvolts to several megaelectronvolts. This sensor makes simultaneous angular measurements of electron fluxes from the tens of kiloelectronvolts to about 1 megaelectronvolt. The same measurements can be extended down to approximately 1 kiloelectronvolt per nucleon,with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

Clark, G.↗
NASA NTRS2018

Early Earth and Rocky Extrasolar Planet Characterization

Scientists are currently designing instruments, telescopes, and spacecraft to search for evidence of life beyond Earth. This search for life beyond Earth comes with an expectation to detect life that is different than the life found on modern-day Earth. But scientists will also be expected to provide compelling proof behind any claims that we are not alone. These two expectations are seemingly at odds with each other, because it will be easiest to provide compelling evidence for life when we have a deep understanding of the life we are looking at.The study of Earth history provides a means to reconcile this tension. Different periods of Earth history present us with biospheres that are dramatically different from modern-day Earth, but for which we have abundant data. This informs our understanding of habitability, because of the variety of global chemical and climatic conditions in Earth history for which we know life has thrived. The study of Earth history also informs our understanding of how to detect life; as the global influences of life have completely changed, so have the detectable features of Earth's biosphere.The appreciation of our home planet as a tightly coupled system also provides us top-level lessons for how to search for an even broader set of biospheres with a wider variety of detectable features. The study of Earth history has taught us that life is a both a function of and critical forcing on the planetary environment. Numerical models of these interactions can by driven by our understanding of Earth history, and be validated against the geological and geochemical data. These models can then be applied to a wider variety of planetary conditions. This will help scientists determine what kinds of life are possible, and eventually help them recognize and confirm the presence of life on rocky planets around other stars.

Domagal-Goldman, Shawn D.↗
NASA NTRS2014

SporeSat

Project Overview: SporeSat is a fundamental space biology science space mission to investigate biophysical mechanisms of plant gravity sensing using a "lab-on-a-chip" experimental approach. The unicellular germinating Ceratopteris richardii fern spore will be studied in outer space. Science Objective: SporeSat shall determine gravity thresholds for calcium ion (Ca2+) channel activation in wild-fern spores. Why This is Important: Ion channels are critical to the functioning of biological organisms, including humans. Ion channels are key components of the nervous system as well as cardiac, skeletal, and smooth muscle function, transport of nutrients and ions, T-cell activation, and pancreatic beta-cell insulin release. Ion channels are often the target of the search for new drugs.

Space Biology↗
NASA NTRS2018

San Francisco Bar Pilot Fatigue Study

The purpose of this study was to evaluate the extent of fatigue among San Francisco Bar Pilots (Maritime Pilots) and its potential impact on safety, and to make recommendations concerning how the risk of fatigue could be managed. Information was gathered via a literature review, observations of Bar Pilots at work, surveys, a task analysis, and an analysis of dispatch records.The work of San Francisco Bar Pilots involves an unusual mix of activities and job demands. Their work calls for situational awareness, reasoning, communication, and perceptual abilities comparable to those required by airline pilots and air traffic controllers. Errors can have severe consequences for public safety and the environment, as well as significant financial costs. Fatigue is increasingly recognized as a hazard that must be managed by the transportation industry. The reduced sleep quality and quantity experienced by personnel who work at night, in conjunction with human circadian rhythms can lead to an operationally significant level of cognitive impairment. The cognitive impact of fatigue includes functions that are critical to safe maritime piloting, such as vigilance, judgment, reaction time and communication. The surveys distributed to Bar Pilots did not uncover evidence of widespread fatigue. The survey results also suggested that fatigue was not a major concern of Bar Pilots. Bar Pilots had overall low scores on the subjective fatigue measures used in the survey, and generally assessed the safety risk due to fatigue as low. Compared to air traffic controllers, Bar Pilots gave significantly lower ratings on questions concerning the prevalence and impact of fatigue. The application of fatigue modeling software to Bar Pilot dispatch records identified that in most cases, pilot's cognitive effectiveness was predicted to be acceptable during their duty periods. However, these results could not be verified with objective data.The study identified a number of fatigue issues that deserve attention. These include Bar Pilot work periods that frequently infringe on the circadian low, consecutive work periods without a significant break, consecutive periods of night work, unpredictable work schedules, start time variability, the potential for sleep inertia, and the number of pilots on the board at any given time.

fatigue↗
NASA NTRS2018

Spectral Response and Effective Area Functions of the Hitomi Imaging Instruments

We describe the tools and the underlying methods and principles for generating the spectral response functions for the four imaging instruments that were flown on the Hitomi x-ray astronomy satellite [Soft X-ray Spectrometer, or SXS; Soft X-ray Imager, or SXI, and two Hard X-ray Imagers, or HXI]. In essence, the spectral response function is a temporally and spatially averaged effective area and line-spread-function. For model-fittingx-ray spectra from an instrument, the spectral response function encapsulates the end-to-end physics of the entire system from telescope to detector, and also includes satellite attitude drift, exposure corrections, and in the case of the HXIs, drift in the telescope/detector alignment system. Accuracy in the construction of the spectral response functions is, therefore, critical to maximize the science return from the data.

Yaqoob, Tahir↗
NASA NTRSDate not supplied

Two is One, One is None: A Discussion on Redundancy

Redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the form of a backup or fail-safe. But the topic of redundancy can be a contentious topic; what is too little, too much, and just right may not be readily apparent. This presentation will be a discussion on redundancy situations from different industries as well as the evolving nature of the “best” amount of redundancy.

Redundancy↗