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At least 361 records · Page 20

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 8: Open-cycle MHD

Electric power plant costs and efficiencies are presented for three basic open-cycle MHD systems: (1) direct coal fired system, (2) a system with a separately fired air heater, and (3) a system burning low-Btu gas from an integrated gasifier. Power plant designs were developed corresponding to the basic cases with variation of major parameters for which major system components were sized and costed. Flow diagrams describing each design are presented. A discussion of the limitations of each design is made within the framework of the assumptions made.

Hoover, D. Q.↗

Crop water-stress assessment using an airborne thermal scanner

An airborne thermal scanner was used to measure the temperature of a wheat crop canopy in Phoenix, Arizona. The results indicate that canopy temperatures acquired about an hour and a half past solar noon were well correlated with presunrise plant water tension, a parameter directly related to plant growth and development. Pseudo-colored thermal images reading directly in stress degree days, a unit indicative of crop irrigation needs and yield potential, were produced. The aircraft data showed significant within-field canopy temperature variability, indicating the superiority of the synoptic view provided by aircraft over localized ground measurements. The standard deviation between airborne and ground-acquired canopy temperatures was 2 C or less.

Millard, J. P.↗

Airborne thermography for crop water stress assessment

Aircraft overflights to obtain canopy temperatures of six differentially irrigated plots of durum wheat were made at Phoenix, Arizona on 1 and 29 April 1976. The data were acquired by a Texas Instruments model RS-25 infrared line scanner operating in the 8 to 14 micrometer bandpass region. Concurrently, plant water tension was measured on the ground with the Scholander pressure bomb technique. The results indicated that canopy temperatures acquired by aircraft about an hour and a half past solar noon correlated well with presunrise plant water tension - a parameter directly related to plant growth and development. The aircraft data also showed significant within-field canopy temperature variability, indicating the superiority of the synoptic view provided by aircraft over the more spotty view obtained by ground-operated infrared thermometers.

Millard, J. P.↗

Evaluation of the ECAS open cycle MHD power plant design

The Energy Conversion Alternatives Study (ECAS) MHD/steam power plant is described. The NASA critical evaluation of the design is summarized. Performance of the MHD plant is compared to that of the other type ECAS plant designs on the basis of efficiency and the 30-year levelized cost of electricity. Techniques to improve the plant design and the potential performance of lower technology plants requiring shorter development time and lower development cost are then discussed.

Seikel, G. R.↗

Solar parabolic dish thermal power systems - Technology and applications

Activities of two projects at JPL in support of DOE's Small Power Systems Program are reported. These two projects are the Point-Focusing Distributed Receiver (PFDR) Technology Project and the Point-Focusing Thermal and Electric Applications (PFTEA) Project. The PFDR Technology Project's major activity is developing the technology of solar concentrators, receivers and power conversion subsystems suitable for parabolic dish or point-focusing distributed receiver power systems. Other PFDR activities include system integration and cost estimation under mass production, as well as the testing of the hardware. The PFTEA Project's first major activity is applications analysis, that is seeking ways to introduce PFDR systems into appropriate user sectors. The second activity is systems engineering and development wherein power plant systems are analyzed for specific applications. The third activity is the installation of a series of engineering experiments in various user environments to obtain actual operating experience

Lucas, J. W.↗

A universal model for estimating wheat yields

A universal wheat yield model applicable to both fall- and spring-planted wheat was developed to show separate and joint effects of weather and culture on yields. Data from state experiment stations in a wide range of climates in the U.S. Great Plains were used to build basic relationships among yields, weather, and culture. The application of the model on a macroclimatic scale in the U.S., the U.S.S.R., and India is discussed along with potential improvements.

Feyerherm, A. M.↗

Coal liquefaction processes and development requirements analysis for synthetic fuels production

Focus of the study is on: (1) developing a technical and programmatic data base on direct and indirect liquefaction processes which have potential for commercialization during the 1980's and beyond, and (2) performing analyses to assess technology readiness and development trends, development requirements, commercial plant costs, and projected synthetic fuel costs. Numerous data sources and references were used as the basis for the analysis results and information presented.

Source record↗

Pilot interaction with automated airborne decision making systems

Progress was made in the three following areas. In the rule-based modeling area, two papers related to identification and significane testing of rule-based models were presented. In the area of operator aiding, research focused on aiding operators in novel failure situations; a discrete control modeling approach to aiding PLANT operators was developed; and a set of guidelines were developed for implementing automation. In the area of flight simulator hardware and software, the hardware will be completed within two months and initial simulation software will then be integrated and tested.

Rouse, W. B.↗

The crop growth research chamber: A ground-based facility for CELSS research

A ground based facility for the study of plant growth and development under stringently controlled environments is being developed by the Closed Ecological Life Support System (CELSS) program at the Ames Research Center. Several Crop Growth Research Chambers (CGRC) and laboratory support equipment provide the core of this facility. The CGRC is a closed (sealed) system with a separate recirculating atmosphere and nutrient delivery systems. The atmospheric environment, hydroponic environment, systems controls, and data acquisition are discussed.

Bubenheim, David L.↗

Wide band fiber-optic communications

A number of optical communication lines are now in use at the Kennedy Space Center (KSC) for the transmission of voice, computer data and video signals. At the present time most of these channels utilize a single carrier wavelength centered near 1300 nm. As a result of previous work the bandwidth capacity of a number of these channels is being increased by transmitting another signal in the 1550 nm region on the same fiber. This is accomplished by means of wavelength division multiplexing (WDM). It is therefore important to understand the bandwidth properties of the installed fiber plant. This work developed new procedures for measuring the bandwidth of fibers in both the 1300nm and 1550nm region. In addition, a preliminary study of fiber links terminating in the Engineering Development Laboratory was completed.

Bates, Harry E.↗

Integrated developmental model of life-support capabilities in wheat

The objective of this project was to develop a model for CO2, O2, H2O, and nitrogen use during the life cycle of wheat. Spreadsheets and accompanying graphs were developed to illustrate plant population reactions to environmental parameters established in the Controlled Ecological Life Support System (CELSS) program at Kennedy Space Center, Fl. The spreadsheets and graphs were produced using validated biomass production chamber (BPC) data from BWT931. Conditions of the BPC during the 83 day plant growth period were as follows: The BPC area is 27.8 m(exp 2), volume is 113 m(exp 3). Temperatures during the 83 day plant growth period ranged from 16.3 to 24.8 C during the light cycle (except for day 69, when the minimum and maximum temperatures were 7.7 C and 7.9 C, respectively) and 14.5 C and 23.6 C during the dark cycle (except for day 49, when the minimum and maximum temperatures were 11.1 C and 11.3 C, respectively). Relative humidity was 85 percent for the first seven days of plant growth, and 70 percent thereafter. The plant leaf canopy area was 10 m(exp 2). Presented is a list and explanation of each spreadsheet and accompanying graph(s), conditions under which the data were collected, and formulas used to obtain each result.

Darnell, R. L.↗

Artificial Soil With Build-In Plant Nutrients

Nutrients contained in sandlike material. Artificial soil provides nutrients to plants during several growing seasons without need to add fertilizer or nutrient solution. When watered, artificial soil slowly releases all materials a plant needs to grow. Developed as medium for growing crops in space. Also used to grow plants on Earth under controlled conditions or even to augment natural soil.

Ming, Douglas W.↗

Effect of microgravity on stress ethylene and carbon dioxide production in sweet clover (Melilotus alba L.)

The study of higher plant growth and development in the microgravity (micro-g) environment continues to be a challenge. This is in part a result of the available flight qualified hardware with restrictive closed gas environments. This point is underscored by considering that gas exchange of seedlings grown in microgravity may be further limited owing to a thicker layer of water wicked onto the roots and to the absence of convective mixing. We hypothesized that seedlings grown under such conditions will experience greater hypoxia in microgravity than at Earth gravity, and thus produce greater stress ethylene. We compared flight and ground samples of sweet clover seedlings grown in the Fluid Processing Apparatus (FPA) during STS-57 and found them to contain extremely high levels of carbon dioxide (CO2) and stress ethylene. There were time dependent increases for both gases, and seedling growth was greatly inhibited. We repeated these experiments aboard STS-60 using modified chambers which increased, by fifty fold, the air available to the developing seedlings. Sweet clover seed germination and subsequent seedling growth to eight days within the FPA modified with a gas permeable membrane is not compromised by the microgravity environment.

Gallegos, Gregory L.↗

A New Image for the Water Hyacinth

Walt Disney Company activated a sewage treatment plan using NASA technology to create water hyacinths to clean wastewater by absorbing and metabolizing pollutants. Plants have exciting promise as a natural water purification system which can be established at a fraction of the cost of a conventional sewage treatment facility. Harvested plants can be used as fertilizer. They can also be heat-treated to produce consumer energy in the form of methane gas. If an economical method of drying plants can be developed they may find further utility as high protein animal feed.

Source record↗

Changes in Space Food over the Last 45 Years

The space food system has improved over the last 45 years. With the advances for a Moon base, there is a potential that foods in space will be more like home cooked foods. However, until that happens, there will continue to be dehydrated and thermostablized foods providing the bulk of the astronauts food. In order for the astronauts to have adequate macronutrients, a food system must be developed including raising plants and food preparation, both a major challenge given the limited water, volume, and power. The lunar kitchens will be very different, but good food is essential to maintain good health.

Smith, Scott M.↗

Closed-Loop Performance Measures for Flight Controllers Subject to Neutron-Induced Upsets

It has been observed that atmospheric neutrons can produce single event upsets in digital flight control hardware. The phenomenon has been studied extensively at the chip level, and now system level experiments are underway. In this paper analytical closed-loop performance measures for the tracking error are developed for a plant that is stabilized by a recoverable computer system subject to neutron induced upsets. The underlying model is a Markov jump-linear system with process noise. The steady-state tracking error is expressed in terms of a generalized observability Gramian.

Gray, W. Steven↗

Demonstration of Critical Systems for Propellant Production on Mars for Science and Exploration Missions

A Mars hopper has been proposed as a Mars mobility concept that will also demonstrate and advance in-situ resource utilization. The components needed in a Mars propellant production plant have been developed to various levels of technology maturity, but there is little experience with the systems in a Mars environment. Two systems for the acquisition and compression of the thin carbon dioxide atmosphere were designed, assembled, and tested in a Mars environment chamber. A microchannel sorption pump system was able to raise the pressure from 7 Torr to 450 Torr or from 12 Torr to over 700 Torr in two stages. This data now provides information needed to make additional improvements in the sorption pump technology to increase performance, although a system-level analysis might prove that some amount of pre- or post-compression may be a preferred solution. A mini cryofreezer system was also evaluated as an alternative method for carbon dioxide acquisition and compression. Finally, an electrolysis system was tested and successfully demonstrated start-up operation and thermal stability of all components during long-term operation in the chamber.

Linne, Diane L.↗

New Crop Selection

For extended space flight, reliable food supplies are a necessity. Most of the food products consumed by astronauts today are stored for flight via freeze drying. Fresh food is needed to supplement known national deficiencies in the stored food diet (Cooper et al.). This is so because stored foods can lose nutritional value. Fresh food is the answer to the nutritional demands of space flight. Kennedy Space Center's Utilization and Life Sciences Office (UB-A), under the Exploration Research and Technology Program (UB), conducts research on plant growth and development under International Space Station (ISS) conditions. UB-A analyzes the growth responses of leafy greens in microgravity and through the manipulation of environmental conditions (CO2 levels, light intensity, relative humidity, and water delivery). By manipulating growing conditions researchers can optimize food production using minimal/restricted resources. The New Crop Selection experiments are testing the suitability of leafy crops to ISS conditions. Results from this study showed that 'Dragoon' Lettuce and 'Red Russian' Kale have the largest fresh mass.

Bhuiyan, Ruqayah H.↗