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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

A Goddard Multi-Scale Modeling System with Unified Physics

Numerical cloud resolving models (CRMs), which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Recent GEWEX Cloud System Study (GCSS) model comparison projects have indicated that CRMs agree with observations in simulating various types of clouds and cloud systems from different geographic locations. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that Numerical Weather Prediction (NWP) and regional scale model can be run in grid size similar to cloud resolving model through nesting technique. Current and future NASA satellite programs can provide cloud, precipitation, aerosol and other data at very fine spatial and temporal scales. It requires a coupled global circulation model (GCM) and cloud-scale model (termed a szrper-parameterization or multi-scale modeling -framework, MMF) to use these satellite data to improve the understanding of the physical processes that are responsible for the variation in global and regional climate and hydrological systems. The use of a GCM will enable global coverage, and the use of a CRM will allow for better and more sophisticated physical parameterization. NASA satellite and field campaign can provide initial conditions as well as validation through utilizing the Earth Satellite simulators. At Goddard, we have developed a multi-scale modeling system with unified physics. The modeling system consists a coupled GCM-CRM (or MMF); a state-of-the-art weather research forecast model (WRF) and a cloud-resolving model (Goddard Cumulus Ensemble model). In these models, the same microphysical schemes (2ICE, several 3ICE), radiation (including explicitly calculated cloud optical properties), and surface models are applied. In addition, a comprehensive unified Earth Satellite simulator has been developed at GSFC, which is designed to fully utilize the multi-scale modeling system. A brief review of the multi-scale modeling system with unified physics/simulator and examples is presented in this article.

Tao, W.K.↗
NASA NTRS1989

NASA's CFD Validation Program

With computational fluid dynamics (CFD) becoming a productive research and design tool, the requirement to validate CFD codes has grown significantly. NASA had emphasized CFD validation activities since 1986 when a separate work element was formed to fund experimental activities related to validation. NASA's CFD and CFD validation programs are closely coordinated to ensure that experimental data bases are available as soon as possible for validating codes. In response to industry and academic requirements, four levels of experimental research have been defined as part of CFD validation with NASA's Aeronautics Advisory Committee (AAC) support although only the fourth level actually has the detailed information necessary for validating codes. Critical flow physics especially turbulence modeling are key to improved CFD codes. NASA has focused additional resources on transition and turbulence physics to meet these requirements. With improved turbulence models, CFD codes will be more accurate, robust, and efficient. However, with the level of detailed information available from CFD codes, highly accurate and detailed experiments are required to capture the critical information for validating codes. Advanced instrumentation especially non-intrusive instrumentation is required to acquire this information in validation experiments. The CFD validation program is being coordinated and managed to address these critical activities. A list of experiments which are currently being supported at least partially are included.

Satran, Dale R.↗
NASA NTRS2011

Microphysics in the Multi-Scale Modeling Systems with Unified Physics

In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (l) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, the microphysics developments of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the heavy precipitation processes will be presented.

Tao, Wei-Kuo↗
NASA NTRS2003

The Multipole Structure of Earth's STEP Signal

If there is an interaction in physical law which differentially accelerates the test bodies in a STEP satellite, then the di.erent elements that compose the Earth will most likely have source strengths for this interaction which are not proportional to their mass densities. The rotational flattening of Earth and geographical irregularities of our planet's crust then produces a multipole structure for the Equivalence Principle violating force field which differs from the multipole structure of Earth's ordinary gravity field. Measuring these differences yields key information about the new interaction in physical law which is not attainable by solely measuring differences of test body accelerations.

Nordtvedt, Kenneth↗
NASA NTRS1982

Atmospheric trace molecule spectroscopy

The Spacelab investigation entitled Atmospheric Trace Molecule Spectroscopy (ATMOS) is designed to obtain fundamental information related to the chemistry and physics of the Earth's upper atmosphere using the techniques of infrared absorption spectroscopy. There are two principal objectives to be met. The first is the determination, on a global scale, of the compositional structure of the upper atmosphere and its spatial variability. The establishment of this variability represents the first step toward determining the characteristic residence times for the upper atmospheric constituents; the magnitudes of their sources and sinks; and, ultimately, an understanding of their effects on the stability of the stratosphere. The second objective is to provide the high-resolution, calibrated spectral information which is essential for the detailed design of advanced instrumentation for subsequent global monitoring of specific species found to be critical to atmospheric stability. This information will be disseminated in the form of a three dimensional atlas of solar absorption spectra obtained over a range of latitudes, longitudes, and altitudes.

Farmer, C. B.↗
NASA NTRS2011

Relationship Between Optimal Gain and Coherence Zone in Flight Simulation

In motion simulation the inertial information generated by the motion platform is most of the times different from the visual information in the simulator displays. This occurs due to the physical limits of the motion platform. However, for small motions that are within the physical limits of the motion platform, one-to-one motion, i.e. visual information equal to inertial information, is possible. It has been shown in previous studies that one-to-one motion is often judged as too strong, causing researchers to lower the inertial amplitude. When trying to measure the optimal inertial gain for a visual amplitude, we found a zone of optimal gains instead of a single value. Such result seems related with the coherence zones that have been measured in flight simulation studies. However, the optimal gain results were never directly related with the coherence zones. In this study we investigated whether the optimal gain measurements are the same as the coherence zone measurements. We also try to infer if the results obtained from the two measurements can be used to differentiate between simulators with different configurations. An experiment was conducted at the NASA Langley Research Center which used both the Cockpit Motion Facility and the Visual Motion Simulator. The results show that the inertial gains obtained with the optimal gain are different than the ones obtained with the coherence zone measurements. The optimal gain is within the coherence zone.The point of mean optimal gain was lower and further away from the one-to-one line than the point of mean coherence. The zone width obtained for the coherence zone measurements was dependent on the visual amplitude and frequency. For the optimal gain, the zone width remained constant when the visual amplitude and frequency were varied. We found no effect of the simulator configuration in both the coherence zone and optimal gain measurements.

Gracio, Bruno Jorge Correia↗
NASA NTRS1988

Human adaptation to isolated and confined environments: Preliminary findings of a seven month Antarctic winter-over human factors study

This field study was conducted during the last decade of an austral winter-over at Palmer Station in the Antarctic. The purpose of the study was to understand temporal patterns in physiological arousal and psychological mood over the course of the mission. The investigators were principally interested in how people adapted over time to chronic and acute stressors, and how people use and modify their built environment. Physiological and psychological data were collected several times a week, and information on behavior and the use of physical facilities was collected monthly. Physiological and psychological data were compared with social changes in the setting toward the development of a sequential model of human-environment transactional relationships. Based on the study results, guidelines for design of future isolated and confined environments (ICEs) included: plan space for items which make people feel at home, provide materials to allow people to personalize their environment, allow for flexible environments, provide areas for visual and auditory privacy, equip areas for socializing and remove them from private areas, and provide facilities for exercise and for projects involving physical activity. The study offers guidelines about patterns of adaption that could be expected in an ICE, discusses how these settings can be programmed to facilitate successful adjustment, and provides information about how to design future ICE habitats to maximize a healthy living environment.

Evans, Gary W.↗
NASA NTRS2008

A Multi-Scale Modeling System with Unified Physics

Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 km, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. In recent years, exponentially increasing computer power has extended cloud-resolving-mode1 integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique.

Tao, Wei-Kuo↗
NASA NTRS2006

Eta Carinae and the Homunculus: An Astrophysical Laboratory

High spatial resolution spectroscopy with HST/STIS between 1998.0 and 2004.2 has provided much exciting information about the central binary system and the physics of its N-rich, C,O-poor ejecta. Stellar He I profiles, noticeably blue-shifted relative to P Cygni H and Fe II line profiles, originate from the ionized wind region between two massive companions. Changes in profiles of He I singlet and triplet lines provide clues to the excitation mechanisms involved as the hot, UV companion moves in its highly eccentric orbit. For 90% of the 5.54-year period, the spectra of nearby Weigelt blobs and the Little Homunculus include highly excited emission lines of Ar, Ne, and Fe. During the few month-long spectroscopic minimum, these systems are deprived of Lyman continuum. Recombination, plus cooling, occurs. In the skirt region between the bipolar Homunculus, a neutral emission region, devoid of hydrogen emission, glows in Ti II, Fe I, Sr II, Sc II, etc. We find the ejecta to have Ti/Ni abundances nearly 100 times solar, not due to nuclear processing, but due to lack of oxygen. Many metals normally tied up in interstellar dust remain in gaseous phase. Much information is being obtained on the physical processes in these warm N-rich gases, whose excitation varies with time in a predictable pattern. Indeed recent GRB high dispersion spectra include signatures of circumGRB warm gases. This indicates that the early, primordial massive stars have warm massive ejecta reminiscent to that around Eta Carinae.

Gull, Theodore R.↗
NASA NTRS2000

On the Computational Capabilities of Physical Systems: The Impossibility of Infallible Computation - Part 1

In this first of two papers, strong limits on the accuracy of physical computation are established. First it is proven that there cannot be a physical computer C to which one can pose any and all computational tasks concerning the physical universe. Next it is proven that no physical computer C can correctly carry out any computational task in the subset of such tasks that can be posed to C. This result holds whether the computational tasks concern a system that is physically isolated from C, or instead concern a system that is coupled to C. As a particular example, this result means that there cannot be a physical computer that can, for any physical system external to that computer, take the specification of that external system's state as input and then correctly predict its future state before that future state actually occurs; one cannot build a physical computer that can be assured of correctly 'processing information faster than the universe does'. The results also mean that there cannot exist an infallible, general-purpose observation apparatus, and that there cannot be an infallible, general-purpose control apparatus. These results do not rely on systems that are infinite, and/or non-classical, and/or obey chaotic dynamics. They also hold even if one uses an infinitely fast, infinitely dense computer, with computational powers greater than that of a Turing Machine. This generality is a direct consequence of the fact that a novel definition of computation - a definition of 'physical computation' - is needed to address the issues considered in these papers. While this definition does not fit into the traditional Chomsky hierarchy, the mathematical structure and impossibility results associated with it have parallels in the mathematics of the Chomsky hierarchy. The second in this pair of papers presents a preliminary exploration of some of this mathematical structure, including in particular that of prediction complexity, which is a 'physical computation analogue' of algorithmic information complexity. It is proven in that second paper that either the Hamiltonian of our universe proscribes a certain type of computation, or prediction complexity is unique (unlike algorithmic information complexity), in that there is one and only version of it that can be applicable throughout our universe.

Wolpert, David H.↗
NASA NTRS1972

High resolution solar observations from space.

Present ground-based solar observations are limited by the transmission properties of the terrestrial atmosphere, the design of instruments, and the choice of observing locations. Recent improvements in the latter two have made possible observations with MTF around 7% at .5 arc sec and 15% at 1 arc sec. However, the instruments now appear to have been developed as far as the terrestrial atmosphere will permit, and new information will only be determined by space observations. The problems of construction, alignment and thermal control of a very high resolution solar telescope in space are discussed together with various optical systems. The problems of solar physics in which we would expect new information are also discussed, on the basis of recent high-resolution observations from the ground.

Zirin, H.↗
NASA NTRS1986

Physics through the 1990s: Scientific interfaces and technological applications

The volume examines the scientific interfaces and technological applications of physics. Twelve areas are dealt with: biological physics-biophysics, the brain, and theoretical biology; the physics-chemistry interface-instrumentation, surfaces, neutron and synchrotron radiation, polymers, organic electronic materials; materials science; geophysics-tectonics, the atmosphere and oceans, planets, drilling and seismic exploration, and remote sensing; computational physics-complex systems and applications in basic research; mathematics-field theory and chaos; microelectronics-integrated circuits, miniaturization, future trends; optical information technologies-fiber optics and photonics; instrumentation; physics applications to energy needs and the environment; national security-devices, weapons, and arms control; medical physics-radiology, ultrasonics, MNR, and photonics. An executive summary and many chapters contain recommendations regarding funding, education, industry participation, small-group university research and large facility programs, government agency programs, and computer database needs.

Source record↗
NASA NTRS1993

A catalog of chromospherically active binary stars (second edition)

The catalog contains 206 spectroscopic binary systems with at least one late-type component that shows Ca II H and K emission in its spectrum. These systems include the classical RS CVn binaries and BY Dra binaries. The catalog summarizes information on the photometric, spectroscopic, orbital, and physical properties of the systems as well as space motions and positions. Up to 42 'parameters' for each stellar system are listed followed by the appropriate reference to direct interested colleagues to the original papers. A comprehensive selection of further information for each star is given in the individual notes. In addition, the catalog contains a candidate list of 138 stars that have similar characteristics but are not definitely known binaries or have not had Ca II H and K emission observed.

Strassmeier, K. G.↗
NASA NTRS2010

Using Analog Field Tests To Link and Prepare Science and In-Situ Resource Utilization for Future Space Missions

A major goal of NASA s human exploration program is to learn how to use the resources of space, known as In-Situ Resource Utilization (ISRU), to lower the cost and risk of human space exploration. Successful implementation of ISRU requires detailed knowledge of surface and subsurface materials, minerals, and volatiles that may be present. This same information is required to better understand the physical and geologic composition, structure, origin, and evolution of the Moon, Mars, and other extraterrestrial bodies of interest. It is also important to recognize that while ISRU and science objectives may be similar, the desired method or hardware to achieve the information desired may be drastically different. One method to promote understanding, coordination, and joint development of instruments and operations between Science and ISRU is the use of analog field demonstrations.

Sanders, Gerald B.↗
NASA NTRS1963

Radio Tracking of Mariner II and Its Scientific Implications

Precise two-way Doppler tracking of Mariner II during its 129-day flight to Venus and beyond has provided scientists with basic information that will help further refine physical constants that are important in understanding the solar system and the earth.

MARINER II SPACE PROBE↗
NASA NTRS1972

A proposal for preprocessing, reduction, and selection of visual information in airborne flight simulation

A noncritical empirical detail-by-detail transformation of environmental information into flight display by purely physical methods characterizes the textured visual simulation as indiscernibly identical with the real scene. This method uses image storage, readout, image transformation, and graphic display to present a true color visual flight image to the pilot onboard aircraft in a purely electronic manner, employing analog-hybrid techniques.

Gaertner, K.↗
NASA NTRS1973

Arousal from sleep by noises from aircraft with and without acoustically treated nacelles

The electroencephalographic and behavioral responses during sleep of four subjects, aged 46 to 58 years, to three types of noises were tested over 14 consecutive nights. The stimuli were two DC-8 jet landing noises (each 30 seconds in duration and coming from DC-8 aircraft with and without acoustical treatment on the engine nacelles) and a 4-second burst of pink noise. Each of the noises was tested at nominal intensities of 61 and 79 dBA. Other physical descriptors of the noises were measured or computed. The results indicate that for an equivalent degree of sleep disruption, noise form the jet aircraft with untreated nacelles must be about 6 dBA less intense than the jet with acoustically treated nacelles. Predictions of the effects of noise on sleep appear, tentatively, to attain the highest accuracy when the physical descriptor of noise intensity includes information about the impulsive characteristics of that noise as well as its long-term spectral content.

Lukas, J. S.↗