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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

Ray, Asit K.↗
NASA NTRS1981

Advanced development: Fuels

The solar thermal fuels and chemicals program at Jet Propulsion Laboratory are described. High technology is developed and applied to displace fossil fuel (oil) use in the production/processing of valuable fuels and chemicals. The technical and economic feasibility is demonstrated to extent that enables the industry to participate and commercialize the product. A representative process, namely Furfural production with a bottoming of acetone, butanol and ethanol, is described. Experimental data from all solar production of furfural is discussed. Estimates are given to show the attractiveness of this process, considering its flexibility to be adaptable to dishes, troughs or central receivers. Peat, lignite and low rank coal processing, heavy oil stripping and innovative technologies for process diagnostics and control are mentioned as examples of current projects under intensive development.

Ramohalli, K.↗
NASA NTRS1981

The CELSS program - An overview of its structure and use of computer modelling

NASA has initiated a research program, CELSS, directed at the acquisition of the knowledge and technology required for the development of an autonomous, regenerative life support system. The program is structured to promote effective, cooperative research in fundamental, applied and engineering science. The initial research thrusts involve investigations into problems of food production, waste processing and system control and integration. In the area of food production both conventional, higher plant-based processes as well as chemosynthetic food production technologies are being investigated. Alternative waste processing procedures, both biological and physicochemical, are being examined. Computer based modelling as an aid to design and analysis is an integral part of the approach to system control and management. A mass balance model depicting the flow of elemental mass in a conceptualized closed, regenerative life support system is described.

Averner, M. M.↗
NASA NTRS1993

Fuel-rich catalytic combustion of a high density fuel

Fuel-rich catalytic combustion (ER is greater than 4) of the high density fuel exo-tetrahydrocyclopentadiene (JP-10) was studied over the equivalence ratio range 5.0 to 7.6, which yielded combustion temperatures of 1220 to 1120 K. The process produced soot-free gaseous products similar to those obtained with iso-octane and jet-A in previous studies. The measured combustion temperature agreed well with that calculated assuming soot was not a combustion product. The process raised the effective hydrogen/carbon (H/C) ratio from 1.6 to over 2.0, thus significantly improving the combustion properties of the fuel. At an equivalence ratio near 5.0, about 80 percent of the initial fuel carbon was in light gaseous products and about 20 percent in larger condensable molecules. Fuel-rich catalytic combustion has now been studied for three fuels with H/C ratios of 2.25 (iso-octane), 1.92 (jet-A), and 1.6 (JP-10). A comparison of the product distribution of these fuels shows that, in general, the measured concentrations of the combustion products were monotonic functions of the H/C ratio with the exception of hydrogen and ethylene. In these cases, data for JP-10 fell between iso-octane and jet-A rather than beyond jet-A. It is suggested that the ring cross-linking structure of JP-10 may be responsible for this behavior. All the fuels studied showed that the largest amounts of small hydrocarbon molecules and the smallest amounts of large condensable molecules occurred at the lower equivalence ratios. This corresponds to the highest combustion temperatures used in these studies. Although higher temperatures may improve this mix, the temperature is limited. First, the life of the present catalyst would be greatly shortened when operated at temperatures of 1300 K or greater. Second, fuel-rich catalytic combustion does not produce soot because the combustion temperatures used in the experiments were well below the threshold temperature (1350 K) for the formation of soot. Increasing the temperature above this value would remove the soot-free nature of the process. Since all the fuels studied show a similar breakdown of the primary fuel into smaller molecular combustion products, this technique can be applied to all hydrocarbon fuels.

Brabbs, Theodore A.↗
NASA NTRS1990

CELSS research and development program

Research in Controlled Ecological Life Support Systems (CELSS) conducted by NASA indicate that plant based systems are feasible candidates for human support in space. Ames has responsibility for research and development, systems integration and control, and space flight experiment portions of the CELSS program. Important areas for development of new methods and technologies are biomass production, waste processing, water purification, air revitalization, and food processing. For the plant system, the approach was to identify the flexibility and response time for the food, water, and oxygen production, and carbon dioxide consumption processes. Tremendous increases in productivity, compared with terrestrial agriculture, were realized. Waste processing research emphasizes recycle (transformation) of human wastes, trash, and inedible biomass to forms usable as inputs to the plant production system. Efforts to improve efficiency of the plant system, select new CELSS crops for a balanced diet, and initiate closed system research with the Crop Growth Research Chambers continue. The System Control and Integration program goal is to insure orchestrated system operation of the biological, physical, and chemical operation of the biological, physical, and chemical component processors of the CELSS. Space flight studies are planned to verify adequate operation of the system in reduced gravity or microgravity environments.

Bubenheim, David↗
NASA NTRS1984

Radiometric Calibration and Geocoded Precision Processing of LANDSAT-4 Multispectral Scanner Products by the Canada Centre for Remote Sensing

Inherent in the method used by CCRS for the radiometric calibration of LANDSAT-4 MSS data is the possibility for the user to convert the corrected digital values to the absolute scene radiance of the target under observation. The generation of the constants needed for this final conversion requires both the pre-launch and post-launch radiometric calibration constants as supplied by NASA. Results of some preliminary comparative studies of the radiometric properties of the LANDSAT-4 MSS versus earlier satellites in the LANDSAT series are presented as well as early observations on the stability of the calibration data, within one scene, within one orbit, and over a period of several months. Residual striping in the corrected products is estimated. The method used to perform precision processing of the LANDSAT MSS data for generating geocoded or map compatible LANDSAT MSS products in the Unviersal Transverse Mercator projection is also reviewed. LANDSAT-4 MSS precision processed products are evaluated for geodetic accuracy, and are compared to similar products from the previous LANDSAT satellites to assess the orbit independent registration accuracy.

Murphy, J.↗
NASA NTRS1990

Spallation processes and nuclear interaction products of cosmic rays

Most cosmic-ray nuclei heavier than helium have suffered nuclear collisions in the interstellar gas, with transformation of nuclear composition. The isotopic and elemental composition at the sources has to be inferred from the observed composition near the Earth. The source composition permits tests of current ideas on sites of origin, nucleosynthesis in stars, evolution of stars, the mixing and composition of the interstellar medium and injection processes prior to acceleration. The effects of nuclear spallation, production of radioactive nuclides and the time dependence of their decay provide valuable information on the acceleration and propagation of cosmic rays, their nuclear transformations, and their confinement time in the Galaxy. The formation of spallation products that only decay by electron capture and are relatively long-lived permits an investigation of the nature and density fluctuations (like clouds) of the interstellar medium. Since nuclear collisions yield positrons, antiprotons, gamma rays and neutrinos, we shall discuss these topics briefly.

Non-NASA Center↗
NASA NTRS2019

GeoNEX: A Cloud Gateway for Near Real-time Processing of Geostationary Satellite Products

The emergence of a new generation of geostationary satellite sensors provides land andatmosphere monitoring capabilities similar to MODIS and VIIRS with far greater temporal resolution (5-15 minutes). However, processing such large volume, highly dynamic datasets requires computing capabilities that (1) better support data access and knowledge discovery for scientists; (2) provide resources to enable real-time processing for emergency response (wildfire, smoke, dust, etc.); and (3) provide reliable and scalable services for the broader user community. This paper presents an implementation of GeoNEX (Geostationary NASA-NOAA Earth Exchange) services that integrate scientific algorithms with Amazon Web Services (AWS) to provide near realtime monitoring (~5 minute latency) capability in a hybrid cloud-computing environment. It offers a user-friendly, manageable and extendable interface and benefits from the scalability provided by Amazon Web Services. Four use cases are presented to illustrate how to (1) search and access geostationary data; (2) configure computing infrastructure to enable near real-time processing; (3) disseminate and utilize research results, visualizations, and animations to concurrent users; and (4) use a Jupyter Notebook-like interface for data exploration and rapid prototyping. As an example of (3), the Wildfire Automated Biomass Burning Algorithm (WF_ABBA) was implemented on GOES-16 and -17 data to produce an active fire map every 5 minutes over the conterminous US. Details of the implementation strategies, architectures, and challenges of the use cases are discussed.

GeoNEX↗
NASA NTRS1973

Mineral oils

The characteristics of lubricants made from mineral oils are discussed. Types and compositions of base stocks are reviewed and the product demands and compositions of typical products are outlined. Processes for commercial production of mineral oils are examined. Tables of data are included to show examples of product types and requirements. A chemical analysis of three types of mineral oils is reported.

Furby, N. W.↗
NASA NTRS1981

Avenues and incentives for commercial use of a low-gravity environment

The scientific and commercial utilization of the low-g environments for materials research and for process and product development is considered. Any products of commercial interest which necessitate processing in space will probably be low volume, high value items. To encourage the commercialization of materials processing in low-g, NASA, in parallel with establishing and demonstrating the scientific/technological precepts for analyzing and using a low-g environment, is establishing the legal and management mechanisms to share in the cost and risk of early commercial ventures, and is now working with commercial firms on a case-by basis to explore applications of this new technology to specific needs of the company.

Brown, R. L.↗
NASA NTRS2001

Space Weathering in the Mercurian Environment

Space weathering processes are known to be important on the Moon. These processes both create the lunar regolith and alter its optical properties. Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will also incur the effects of space weathering. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes and the products of those processes. It should be possible to observe the effects of these differences in Vis (visible)/NIR (near infrared) spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the Fe content of the Mercurian surface. Additional information is contained in the original extended abstract.

Noble, S. K.↗
NASA NTRS2009

A Reference Model for Software and System Inspections. White Paper

Software Quality Assurance (SQA) is an important component of the software development process. SQA processes provide assurance that the software products and processes in the project life cycle conform to their specified requirements by planning, enacting, and performing a set of activities to provide adequate confidence that quality is being built into the software. Typical techniques include: (1) Testing (2) Simulation (3) Model checking (4) Symbolic execution (5) Management reviews (6) Technical reviews (7) Inspections (8) Walk-throughs (9) Audits (10) Analysis (complexity analysis, control flow analysis, algorithmic analysis) (11) Formal method Our work over the last few years has resulted in substantial knowledge about SQA techniques, especially the areas of technical reviews and inspections. But can we apply the same QA techniques to the system development process? If yes, what kind of tailoring do we need before applying them in the system engineering context? If not, what types of QA techniques are actually used at system level? And, is there any room for improvement.) After a brief examination of the system engineering literature (especially focused on NASA and DoD guidance) we found that: (1) System and software development process interact with each other at different phases through development life cycle (2) Reviews are emphasized in both system and software development. (Figl.3). For some reviews (e.g. SRR, PDR, CDR), there are both system versions and software versions. (3) Analysis techniques are emphasized (e.g. Fault Tree Analysis, Preliminary Hazard Analysis) and some details are given about how to apply them. (4) Reviews are expected to use the outputs of the analysis techniques. In other words, these particular analyses are usually conducted in preparation for (before) reviews. The goal of our work is to explore the interaction between the Quality Assurance (QA) techniques at the system level and the software level.

He, Lulu↗
NASA NTRS2006

Manufacturing Precise, Lightweight Paraboloidal Mirrors

A process for fabricating a precise, diffraction- limited, ultra-lightweight, composite- material (matrix/fiber) paraboloidal telescope mirror has been devised. Unlike the traditional process of fabrication of heavier glass-based mirrors, this process involves a minimum of manual steps and subjective judgment. Instead, this process involves objectively controllable, repeatable steps; hence, this process is better suited for mass production. Other processes that have been investigated for fabrication of precise composite-material lightweight mirrors have resulted in print-through of fiber patterns onto reflecting surfaces, and have not provided adequate structural support for maintenance of stable, diffraction-limited surface figures. In contrast, this process does not result in print-through of the fiber pattern onto the reflecting surface and does provide a lightweight, rigid structure capable of maintaining a diffraction-limited surface figure in the face of changing temperature, humidity, and air pressure. The process consists mainly of the following steps: 1. A precise glass mandrel is fabricated by conventional optical grinding and polishing. 2. The mandrel is coated with a release agent and covered with layers of a carbon- fiber composite material. 3. The outer surface of the outer layer of the carbon-fiber composite material is coated with a surfactant chosen to provide for the proper flow of an epoxy resin to be applied subsequently. 4. The mandrel as thus covered is mounted on a temperature-controlled spin table. 5. The table is heated to a suitable temperature and spun at a suitable speed as the epoxy resin is poured onto the coated carbon-fiber composite material. 6. The surface figure of the optic is monitored and adjusted by use of traditional Ronchi, Focault, and interferometric optical measurement techniques while the speed of rotation and the temperature are adjusted to obtain the desired figure. The proper selection of surfactant, speed or rotation, viscosity of the epoxy, and temperature make it possible to obtain the desired diffraction-limited, smooth (1/50th wave) parabolic outer surface, suitable for reflective coating. 7. A reflective coat is applied by use of conventional coating techniques. 8. Once the final figure is set, a lightweight structural foam is applied to the rear of the optic to ensure stability of the figure.

Hermann, Frederick Thomas↗
NASA NTRS2011

CloudSat Reflectivity Data Visualization Inside Hurricanes

We have presented methods to rapidly produce visualization and outreach products from CloudSat data for science and the media These methods combine data from several sources in the product generation process In general, the process can be completely automatic, producing products and notifying potential users

remote science↗
NASA NTRS1995

A synthetic design environment for ship design

Rapid advances in computer science and information system technology have made possible the creation of synthetic design environments (SDE) which use virtual prototypes to increase the efficiency and agility of the design process. This next generation of computer-based design tools will rely heavily on simulation and advanced visualization techniques to enable integrated product and process teams to concurrently conceptualize, design, and test a product and its fabrication processes. This paper summarizes a successful demonstration of the feasibility of using a simulation based design environment in the shipbuilding industry. As computer science and information science technologies have evolved, there have been many attempts to apply and integrate the new capabilities into systems for the improvement of the process of design. We see the benefits of those efforts in the abundance of highly reliable, technologically complex products and services in the modern marketplace. Furthermore, the computer-based technologies have been so cost effective that the improvements embodied in modern products have been accompanied by lowered costs. Today the state-of-the-art in computerized design has advanced so dramatically that the focus is no longer on merely improving design methodology; rather the goal is to revolutionize the entire process by which complex products are conceived, designed, fabricated, tested, deployed, operated, maintained, refurbished and eventually decommissioned. By concurrently addressing all life-cycle issues, the basic decision making process within an enterprise will be improved dramatically, leading to new levels of quality, innovation, efficiency, and customer responsiveness. By integrating functions and people with an enterprise, such systems will change the fundamental way American industries are organized, creating companies that are more competitive, creative, and productive.

Chipman, Richard R.↗
NASA NTRS2011

Ares I-X Range Safety Analyses Overview

Ares I-X was the first test flight of NASA's Constellation Program's Ares I Crew Launch Vehicle designed to provide manned access to low Earth orbit. As a one-time test flight, the Air Force's 45th Space Wing required a series of Range Safety analysis data products to be developed for the specified launch date and mission trajectory prior to granting flight approval on the Eastern Range. The range safety data package is required to ensure that the public, launch area, and launch complex personnel and resources are provided with an acceptable level of safety and that all aspects of prelaunch and launch operations adhere to applicable public laws. The analysis data products, defined in the Air Force Space Command Manual 91-710, Volume 2, consisted of a nominal trajectory, three sigma trajectory envelopes, stage impact footprints, acoustic intensity contours, trajectory turn angles resulting from potential vehicle malfunctions (including flight software failures), characterization of potential debris, and debris impact footprints. These data products were developed under the auspices of the Constellation's Program Launch Constellation Range Safety Panel and its Range Safety Trajectory Working Group with the intent of beginning the framework for the operational vehicle data products and providing programmatic review and oversight. A multi-center NASA team in conjunction with the 45th Space Wing, collaborated within the Trajectory Working Group forum to define the data product development processes, performed the analyses necessary to generate the data products, and performed independent verification and validation of the data products. This paper outlines the Range Safety data requirements and provides an overview of the processes established to develop both the data products and the individual analyses used to develop the data products, and it summarizes the results of the analyses required for the Ares I-X launch.

Starr, Brett R.↗