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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

WaterTAP-REFLO models of Solar Still, Solar Still ZLD, Enhanced Evaporation pond results for baseline analysis

This folder contains results from models that were adapted into WaterTAP-REFLO. The files contain inputs and outputs for solar still, solar still ZLD, and enhanced evaporation pond unit process models for 4 different locations in the USA: Phoenix, Miami, Houston, and Baltimore. The WaterTAP-REFLO implementation may be different and thus may have different results. The data structure and content are described in a ReadMe.txt file. For WaterTAP-REFLO documentation and/or contact the developers please see: https://github.com/watertap-org/watertap-reflo.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1989

A comparison of select image-compression algorithms for an electronic still camera

This effort is a study of image-compression algorithms for an electronic still camera. An electronic still camera can record and transmit high-quality images without the use of film, because images are stored digitally in computer memory. However, high-resolution images contain an enormous amount of information, and will strain the camera's data-storage system. Image compression will allow more images to be stored in the camera's memory. For the electronic still camera, a compression algorithm that produces a reconstructed image of high fidelity is most important. Efficiency of the algorithm is the second priority. High fidelity and efficiency are more important than a high compression ratio. Several algorithms were chosen for this study and judged on fidelity, efficiency and compression ratio. The transform method appears to be the best choice. At present, the method is compressing images to a ratio of 5.3:1 and producing high-fidelity reconstructed images.

Nerheim, Rosalee↗
NASA NTRS1973

Parametric analysis of turbulent wall jets in still air.

An examination has been made of all the data available on incompressible (nominally) plane wall jets in still air, supplementing these when necessary with some additional measurements. For a wall jet in still air, the chief mean flow qualities of interest are the maximum velocity, the inner length scale, and a total thickness, in addition to the wall stress. On the basis of the analysis, a (nominally) plane wall jet flow can be divided into an initial region, a fully developed flow region, and a confined wall jet flow region.

Narasimha, R.↗
NASA NTRS1987

Multiscale turbulence effects in supersonic jets exhausting into still air

A modified version of the multiscale turbulence model of Hanjalic has been applied to the problem of supersonic jets exhausting into still air. In particular, the problem of shock-cell decay through turbulent interaction with the mixing layer has been studied for both mildly interacting and strongly resonant jet conditions. The modified Hanjalic model takes into account the nonequilibrium energy transfer between two different turbulent spectral scales. The turbulence model was incorporated into an existing shock-capturing, parabolized Navier-Stokes computational model in order to perform numerical experiments. The results show that the two-scale turbulence model provides significant improvement over one-scale models in the prediction of plume shock structure for underexpanded supersonic (Mach 2) and sonic (Mach 1) jets. For the supersonic jet, excellent agreement with experiment was obtained for the centerline shock-cell pressure decay up to 40 jet radii. For the sonic jet, the agreement with experiment was not so good, but the two-scale model still showed significant improvement over the one-scale model. It is shown that by relating some of the coefficients in the turbulent-transport equations to the relative time scale for transfer of energy between scales the two-scale model can provide predictions that bound the measured shock-cell decay rate for the sonic jet.

Abdol-Hamid, Khaled S.↗
NASA NTRS1994

Learning random networks for compression of still and moving images

Image compression for both still and moving images is an extremely important area of investigation, with numerous applications to videoconferencing, interactive education, home entertainment, and potential applications to earth observations, medical imaging, digital libraries, and many other areas. We describe work on a neural network methodology to compress/decompress still and moving images. We use the 'point-process' type neural network model which is closer to biophysical reality than standard models, and yet is mathematically much more tractable. We currently achieve compression ratios of the order of 120:1 for moving grey-level images, based on a combination of motion detection and compression. The observed signal-to-noise ratio varies from values above 25 to more than 35. The method is computationally fast so that compression and decompression can be carried out in real-time. It uses the adaptive capabilities of a set of neural networks so as to select varying compression ratios in real-time as a function of quality achieved. It also uses a motion detector which will avoid retransmitting portions of the image which have varied little from the previous frame. Further improvements can be achieved by using on-line learning during compression, and by appropriate compensation of nonlinearities in the compression/decompression scheme. We expect to go well beyond the 250:1 compression level for color images with good quality levels.

Gelenbe, Erol↗
NASA NTRS1954

Vertical Descent and Landing Tests of a 0.13-Scale Model of the Convair XFY-1 Vertically Rising Airplane in Still Air, TED No. NACA DE 368

An investigation is being conducted to determine the dynamic stability and control characteristics of a 0.13-scale flying model of Convair XFY-1 vertically rising airplane. This paper presents the results of flight and force tests to determine the stability and control characteristics of the model in vertical descent and landings in still air. The tests indicated that landings, including vertical descent from altitudes representing up to 400 feet for the full-scale airplane and at rates of descent up to 15 or 20 feet per second (full scale), can be performed satisfactorily. Sustained vertical descent in still air probably will be more difficult to perform because of large random trim changes that become greater as the descent velocity is increased. A slight steady head wind or cross wind might be sufficient to eliminate the random trim changes.

Smith, Charlee C., Jr.↗
NASA NTRS1991

Electronic Still Camera Project on STS-48

On behalf of NASA, the Office of Commercial Programs (OCP) has signed a Technical Exchange Agreement (TEA) with Autometric, Inc. (Autometric) of Alexandria, Virginia. The purpose of this agreement is to evaluate and analyze a high-resolution Electronic Still Camera (ESC) for potential commercial applications. During the mission, Autometric will provide unique photo analysis and hard-copy production. Once the mission is complete, Autometric will furnish NASA with an analysis of the ESC s capabilities. Electronic still photography is a developing technology providing the means by which a hand held camera electronically captures and produces a digital image with resolution approaching film quality. The digital image, stored on removable hard disks or small optical disks, can be converted to a format suitable for downlink transmission, or it can be enhanced using image processing software. The on-orbit ability to enhance or annotate high-resolution images and then downlink these images in real-time will greatly improve Space Shuttle and Space Station capabilities in Earth observations and on-board photo documentation.

Source record↗
DOE OSTI2025

Synthesis of Sandwich-α-Diimine Ligands via Copper-Mediated Stille Coupling

While sandwich diimines have found use in transition metal catalysis, the general method for their preparation has been lacking. Here, this approach utilizes a copper-mediated Stille-type coupling between aryl stannanes and α-diimines bearing 8-bromonaphthylimino group in commercial-grade N,N-dimethylformamide solvent and employs CuI or thiophene-2-carboxylate to promote the reactions. No other additives or bases are required. Electron-poor, electron-rich, heterocyclic, and hindered aryl stannanes can be employed as coupling reagents. Ligand scaffolds derived from structurally diverse α-diketones can be used.

Catalysts↗
DOE OSTI2025

Are humans still necessary? Expanding the discussion

The rise of automation, artificial intelligence (AI), and autonomous systems raises important questions about the future role of humans and the field of human factors/ergonomics in workplaces. This paper builds on Dr. Peter Hancock’s 2023 ‘Are Humans Still Necessary?’ article published in the Ergonomics journal. Using a multi-method approach that included a debate, opinion polling, roundtable discussions, and AI queries, the current effort examined the necessity of human involvement in future work environments. Debate team members presented arguments for and against the need for human workers, considering human factors, technology, and socioeconomic factors. Observations indicate that while AI may handle routine tasks, humans will likely remain essential for complex decision making, creativity, and ethical considerations. The paper advocates for viewing workplace dynamics as collaborative human-AI partnerships rather than competition, highlighting the need for a transdisciplinary approach in which human factors/ergonomics professionals play a vital role in enhancing these relationships.

99 - GENERAL AND MISCELLANEOUS↗
DOE OSTI2023

Why are we still here 80 years later?

The Lab helped end World War II in 1945, but could the Lab survive peace? Join Senior Lab Historian Alan Carr and Historian Nic Lewis as they present “Why we’re still in Business,” examining the role of the Lab once World War II had ended. This presentation, which commemorates the Lab’s 80th anniversary, Carr and Lewis reconsider the popular belief that the Lab nearly ceased to exist after having developed the atomic bombs that helped end war.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2024

General circulation models simulate negative liquid water path–droplet number correlations, but anthropogenic aerosols still increase simulated liquid water path

General circulation models' (GCMs) estimates of the liquid water path adjustment to anthropogenic aerosol emissions differ in sign from other lines of evidence. This reduces confidence in estimates of the effective radiative forcing of the climate by aerosol–cloud interactions (ERFaci). The discrepancy is thought to stem in part from GCMs' inability to represent the turbulence–microphysics interactions in cloud-top entrainment, a mechanism that leads to a reduction in liquid water in response to an anthropogenic increase in aerosols. In the real atmosphere, enhanced cloud-top entrainment is thought to be the dominant adjustment mechanism for liquid water path, weakening the overall ERFaci. We show that the latest generation of GCMs includes models that produce a negative correlation between the present-day cloud droplet number and liquid water path, a key piece of observational evidence supporting liquid water path reduction by anthropogenic aerosols and one that earlier-generation GCMs could not reproduce. However, even in GCMs with this negative correlation, the increase in anthropogenic aerosols from preindustrial to present-day values still leads to an increase in the simulated liquid water path due to the parameterized precipitation suppression mechanism. This adds to the evidence that correlations in the present-day climate are not necessarily causal. We investigate sources of confounding to explain the noncausal correlation between liquid water path and droplet number. These results are a reminder that assessments of climate parameters based on multiple lines of evidence must carefully consider the complementary strengths of different lines when the lines disagree.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1968

Compact solar still Patent

Utilization of solar radiation by solar still for converting salt and brackish water into potable water

Glekas, L. P.↗
NASA NTRS1973

Numerical solution for low-velocity penetration of rigid body into still fluid

A modified marker-and-cell computational method is developed which can be used to study problems related to impact and penetration of a rigid body into a viscous medium. The method has been applied to solving (in two dimensions) the problem of low-velocity penetration of a rigid block into still water. The solution gives the complete pressure and velocity of the flow field so that the force and displacement time histories of the rigid body during the impact and entry phase are evaluated from the boundary stresses imposed by the fluid on the rigid body. Some limited experimental comparisons are also given to demonstrate the feasibility of the computational method.

Cheng, R. Y.-K.↗