DOCSLIB.ORG

Materials Refining for Solar Array Production on the Moon

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Materials Refining for Solar Array Production on the Moon https://ntrs.nasa.gov/search.jsp?R=20060004126 2019-08-29T21:13:16+00:00Z View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by NASA Technical Reports Server NASA/TM—2005-214014 Materials Refining for Solar Array Production on the Moon Geoffrey A. Landis Glenn Research Center, Cleveland, Ohio December 2005 The NASA STI Program Office . in Profile Since its founding, NASA has been dedicated to • CONFERENCE PUBLICATION. Collected the advancement of aeronautics and space papers from scientific and technical science. The NASA Scientific and Technical conferences, symposia, seminars, or other Information (STI) Program Office plays a key part meetings sponsored or cosponsored by in helping NASA maintain this important role. NASA. The NASA STI Program Office is operated by • SPECIAL PUBLICATION. Scientific, Langley Research Center, the Lead Center for technical, or historical information from NASA’s scientific and technical information. The NASA programs, projects, and missions, NASA STI Program Office provides access to the often concerned with subjects having NASA STI Database, the largest collection of substantial public interest. aeronautical and space science STI in the world. The Program Office is also NASA’s institutional • TECHNICAL TRANSLATION. English- mechanism for disseminating the results of its language translations of foreign scientific research and development activities. These results and technical material pertinent to NASA’s are published by NASA in the NASA STI Report mission. Series, which includes the following report types: Specialized services that complement the STI • TECHNICAL PUBLICATION. Reports of Program Office’s diverse offerings include completed research or a major significant creating custom thesauri, building customized phase of research that present the results of databases, organizing and publishing research NASA programs and include extensive data results . even providing videos. or theoretical analysis. Includes compilations of significant scientific and technical data and For more information about the NASA STI information deemed to be of continuing Program Office, see the following: reference value. NASA’s counterpart of peer- reviewed formal professional papers but • Access the NASA STI Program Home Page has less stringent limitations on manuscript at http://www.sti.nasa.gov length and extent of graphic presentations. • E-mail your question via the Internet to • TECHNICAL MEMORANDUM. Scientific [email protected] and technical findings that are preliminary or of specialized interest, e.g., quick release • Fax your question to the NASA Access reports, working papers, and bibliographies Help Desk at 301–621–0134 that contain minimal annotation. Does not contain extensive analysis. • Telephone the NASA Access Help Desk at 301–621–0390 • CONTRACTOR REPORT. Scientific and technical findings by NASA-sponsored • Write to: contractors and grantees. NASA Access Help Desk NASA Center for AeroSpace Information 7121 Standard Drive Hanover, MD 21076 NASA/TM—2005-214014 Materials Refining for Solar Array Production on the Moon Geoffrey A. Landis Glenn Research Center, Cleveland, Ohio Prepared for the Space and Electric Power for Humanity, the Fourth International Symposium on Space Means for Power Utilities, and the Third Wireless Power Transmission Conference cosponsored by the Canadian Aeronautics and Space Institute (CASI) and the Société des Electriciens et des Electroniciens (SEE) Montreal, Canada, August 24–28, 1997, and 29th Photovoltaic Specialists Conference sponsored by the Institute of Electrical and Electronics Engineers, Electron Devices Society New Orleans, Louisiana, May 18–25, 2002 National Aeronautics and Space Administration Glenn Research Center December 2005 This report contains preliminary findings, subject to revision as analysis proceeds. Available from NASA Center for Aerospace Information National Technical Information Service 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076 Springfield, VA 22100 Available electronically at http://gltrs.grc.nasa.gov Refining Lunar Materials for Solar Array Production on the Moon Geoffrey A. Landis National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 Abstract Silicon, aluminum, and glass are the primary raw materials that will be required for production of solar arrays on the moon. A process sequence is proposed for producing these materials from lunar regolith, consisting of separating the required materials from lunar rock with fluorine. The fluorine is brought to the moon in the form of potassium fluoride, and is liberated from the salt by electrolysis in a eutectic salt melt. Tetrafluorosilane produced by this process is reduced to silicon by a plasma reduction stage; the fluorine salts are reduced to metals by reaction with metallic potassium. Fluorine is recovered from residual MgF and CaF2 by reaction with K2O. 1. Background Oxygen, a major component of rocket fuel and also critical for human life support, is a high priority resource to be produced on the moon. Many processes have been proposed to manufacture oxygen from lunar regolith. In the longer term, sustained habitation and industrialization of the moon will require the ability to produce other raw materials from lunar materials. It would be desirable to produce industrial materials as a co-product of oxygen production by reduction of lunar regolith. Production of solar arrays on the moon could have many uses for space industrialization (Refs. 1 to 4). This would allow increasing the power available for lunar facilities with a minimum of material required from the Earth. Increased power availability could be useful in ramping up the production of lunar resources (for example, oxygen) or for other industrial-scale operations, such as powering a mass- driver to deliver resources. Lunar production could also be useful for manufacture of solar arrays for other space applications, including satellites and solar-electric propulsion vehicles, since the ∆V of launching from the lunar surface is considerably less than that of launching from the surface of the Earth, and hence lunar-produced solar arrays could be lower in cost than Earth produced arrays. In the longer term, lunar produced solar arrays would be useful for the proposed production of solar power satellites to produce power in orbit for transmission to other users in space, or ultimately for transmission to the Earth's surface (Ref. 3). An alternate version of the orbital power concept is to produce the electricity by solar arrays directly on the lunar surface, using the moon itself as a large-area platform for beaming the power to the Earth (Refs. 4 to 5). These applications have been widely discussed elsewhere. The details of the process of lunar production of solar cells, on the other hand, have been less widely addressed. Earlier work on this subject is in references (Refs. 1 to 4 and 6). This paper will focus on developing workable production systems to reduce the lunar soil and produce the refined feedstock materials for making solar arrays from materials available on the lunar surface, including both the photovoltaic cell, and also the associated electrical connections and structural elements of the array. Table 1 shows the elements present in the lunar soil at abundances of 0.1 percent (by weight) or higher (Refs. 7 to 9). The processing sequence chosen should optimally recycle all reagents and waste products that are not available on the lunar surface. Since the lunar surface comprises oxides, any reduction process chosen to manufacture purified feedstock materials will simultaneously produce oxygen. NASA/TM—2005-214014 1 2. Solar Cell Production 2.1 Lunar Silicon Production Of the many materials used to make solar cells, only silicon is found in abundance on the moon. As shown in figure 1, after oxygen, silicon is the most abundant component of the lunar soil. Fortunately, silicon solar cells have the largest manufacturing base of any of the solar cell materials. For solar array production from lunar materials, the first requirement would be to demonstrate manufacture of relatively pure silicon from lunar resources. Since this is the major mass component of a solar cell, Si production would be the first step to showing solar cell manufacture is possible. In addition, silicon is the main component for glass. For solar cell operation, it is necessary that the silicon produce be of high purity. "Metallurgical grade" silicon is not acceptable. The allowable impurity level depends on the nature of the impurity atoms. Transition metals such as Fe and Cr serve as recombination centers in silicon, as well as nucleating growth defects, and reduce the efficiency if they are present in significant quantities (Ref. 10). Since iron is the highest mass fraction of the lunar soil after silicon and oxygen, it will be necessary that the silicon production process be adaptable to a method to refine and purify the silicon produced. Silicon can be used to produce several kinds of solar cells, including amorphous, polycrystalline, and conventional and unconventional single-crystal silicon cells. 2.1.1 Amorphous Silicon Amorphous silicon solar cells are normally produced by a plasma deposition process exactly like the one proposed below. This will require a small amount of hydrogen to make the electrical properties acceptable (in fact, the material is more accurately labeled amorphous silicon:hydrogen, or a-Si:H). This will also require a substrate or
Load more

Recommended publications
  • Flux Attenuation at Nrel's High-Flux Solar Furnace
    NREL!TP-471-7294 • UC Category: 1303 • DE95000219 Flux Attenuatio t NREL's High-Flux Solar ce Carl E. Bingham Kent L. Scholl Allan A. Lewandowski National Renewable Energy Laboratory Prepared for the ASME/JSME/JSES International Solar Energy Conference, Maui, HI, March 19-24, 1995 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 A national laboratory of the U.S. Department of Energy managed by Midwest Research Institute for the U.S. Department of Energy under Contract No. DE-AC36-83CH10093 October 1994 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government . Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Available to DOE and DOE contractors from: Office of Scientific and Technical Information (OSTI) P.O. Box62 Oak Ridge, TN 37831 Prices available by calling (61 5) 576-84 01 Available to the public from: National Technical Information Service (NTIS) U.S.
    [Show full text]
  • DOE's National Solar Thermal Test Facility
    CSP Program Summit 2016 DOE’s National Solar Thermal Test Facility (NSTTF) April 20, 2016 William Kolb, Subhash L. Shinde SAND2016-3291C Sandia National Laboratories energy.gov/sunshot Concentrating Solar Technologies Dept. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Albuquerque, New Mexico Corporation,CSP a wholly Program owned subsidiary Summit of Lockheed 2016 Martin Corporation, for the U.S. Department of Energy’senergy.gov/sunshot National Nuclear Security Administration under contract DE-AC04-94AL85000. [email protected], (505) 284-2965 Sandia National Laboratories Vision Development Areas • Develop the next-generation CSP technologies to • Power Tower R&D – Reduce the cost and improve the provide dispatchable, clean solar-thermal generated performance of high-temperature receivers and novel electricity at higher conversion efficiencies heliostats • Realize significant reductions in Levelized Cost of • Thermal Storage R&D - Lower the cost of thermal Energy (LCOE) by making fundamental advances in energy storage through analysis of HTF/material power cycles, receivers, thermal storage, and collectors compatibility and performance evaluation of next- to achieve the intent of the SunShot goals by 2020 generation hardware • Optical Materials and Tools - Address identified cost and performance impacts in the optical systems • System Analysis - Develop models and analysis tools that will aid in the evaluation of CSP components and systems • Dish R&D – Develop thermal storage systems for dish-engine
    [Show full text]
  • The History of Solar
    Solar technology isn’t new. Its history spans from the 7th Century B.C. to today. We started out concentrating the sun’s heat with glass and mirrors to light fires. Today, we have everything from solar-powered buildings to solar- powered vehicles. Here you can learn more about the milestones in the Byron Stafford, historical development of solar technology, century by NREL / PIX10730 Byron Stafford, century, and year by year. You can also glimpse the future. NREL / PIX05370 This timeline lists the milestones in the historical development of solar technology from the 7th Century B.C. to the 1200s A.D. 7th Century B.C. Magnifying glass used to concentrate sun’s rays to make fire and to burn ants. 3rd Century B.C. Courtesy of Greeks and Romans use burning mirrors to light torches for religious purposes. New Vision Technologies, Inc./ Images ©2000 NVTech.com 2nd Century B.C. As early as 212 BC, the Greek scientist, Archimedes, used the reflective properties of bronze shields to focus sunlight and to set fire to wooden ships from the Roman Empire which were besieging Syracuse. (Although no proof of such a feat exists, the Greek navy recreated the experiment in 1973 and successfully set fire to a wooden boat at a distance of 50 meters.) 20 A.D. Chinese document use of burning mirrors to light torches for religious purposes. 1st to 4th Century A.D. The famous Roman bathhouses in the first to fourth centuries A.D. had large south facing windows to let in the sun’s warmth.
    [Show full text]
  • Red Feather Solar Furnace
    Red Feather Solar Furnace Preliminary Proposal Nathan Fisher Leann Hernandez Trevor Scott 2020 Project Sponsor: Red Feather Development Group Faculty Advisor: Dr. Trevas Sponsor Mentor: Chuck Vallance Instructor: Dr. Trevas DISCLAIMER This report was prepared by students as part of a university course requirement. While considerable effort has been put into the project, it is not the work of licensed engineers and has not undergone the extensive verification that is common in the profession. The information, data, conclusions, and content of this report should not be relied on or utilized without thorough, independent testing and verification. University faculty members may have been associated with this project as advisors, sponsors, or course instructors, but as such they are not responsible for the accuracy of results or conclusions. i EXECUTIVE SUMMARY The NAU Capstone team is partnered with Red Feather to design a solar furnace. Red Feather is a non-profit organization that helps the Native American people with their housing needs on the reservation. The Native American people used to receive coal from a power plant, but it was recently shut down. In addition, coal is known to cause respiratory illnesses. The NAU Capstone team was tasked with designing a sustainable and lasting solution to their heating problems. A solar furnace was chosen due to these reasons. Multiple customer needs and engineering requirements were considered in designing the solar furnace. The final design was developed from a decision matrix and refined using both engineering computations, as well as a comprehensive analysis of the failure modes of the device. System heat loss, fan optimization, and solar technology were researched to better understand what materials and what configuration would be best for the solar furnace.
    [Show full text]
  • Solar Furnace
    ©2008 - v 4/15 ______________________________________________________________________________________________________________________________________________________________________ 612-0003 (05-040) Solar Furnace Introduction: What is a solar furnace? Methods of concentrating solar energy have existed for millennia, but it was not until 1949 that the first modern solar furnace was constructed in the Pyrenees. Basically, the purpose of a solar furnace is to generate large amounts of heat without fuel. This is possible by using heat generated by the sun and concentrating it. Solar furnaces are generally used for industrial or experimental purposes; some of the largest can generate heat in excess of 3,000 C. These can be used for disposing of hazardous waste, testing thermal properties of materials, power generation, or possibly weaponry. The primary advantages of solar furnaces are the huge heat capabilities, lack of required fuel, and ease of use. Some disadvantages are high cost, and unreliable sunshine. Description: There are two methods usually used for this: parabolic mirrors with a collector at the focal point, or semicircular troughs of mirrors arranged around a central point. Our solar furnace is the former type. It features a plastic parabolic mirror 30cm in diameter, connected to a plastic base by a support shaft. A property of parabolic mirrors is their ability to focus light or other radiation onto a single point, called the focus. This focus is directly over the center of the mirror, and the distance between this point and the center of the mirror is called the focal length. If one were to place an object directly above the center of the mirror at a distance equal to the focal length, it would be subject to much greater radiation than elsewhere.
    [Show full text]
  • Influences of Optical Factors on the Performance of the Solar Furnace
    energies Article Influences of Optical Factors on the Performance of the Solar Furnace Zhiying Cui 1,2,3,4, Fengwu Bai 1,2,3,4,*, Zhifeng Wang 1,2,3,4 and Fuqiang Wang 5 1 Key Laboratory of Solar Thermal Energy and Photovoltaic System, Chinese Academy of Sciences, Beijing 100190, China; [email protected] (Z.C.); [email protected] (Z.W.) 2 Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China 3 University of Chinese Academy of Sciences, Beijing 100049, China 4 Beijing Engineering Research Center of Solar Thermal Power, Beijing 100190, China 5 Harbin Institute of Technology, Weihai 264209, Shandong, China; [email protected] * Correspondence: [email protected] Received: 14 September 2019; Accepted: 12 October 2019; Published: 17 October 2019 Abstract: In this paper, an optical structure design for a solar furnace is described. Based on this configuration, Monte Carlo ray tracing simulations are carried out to analyze the influences of four optical factors on the concentrated solar heat flux distribution. According to the practical mirror shape adjustment approach, the curved surface of concentrator facet is obtained by using the finite element method. Due to the faceted reflector structure, the gaps between the adjacent mirror arrays and the orientations of facets are also considered in the simulation model. It gives the allowable error ranges or restrictions corresponding to the optical factors which individually effect the system in Beijing: The tilt error of heliostat should be less than 4 mrad; the tilt error of the concentrator in the orthogonal directions should be both less than 2 mrad; the concentrator facets with the shape most approaching paraboloid would greatly resolve slope error and layout errors arising in the concentrator.
    [Show full text]
  • Innovative Solar Technology from the Netherlands Visit Us the PV at B4G/B 1S2EC
    September 2011 SEC Hamburg PV Innovative solar technology from the Netherlands Visit us at the PV SEC B4G/B12 Launchingof evaporation cabinet • • • • • • • • • • • • Innovative solar technology from the Netherlands Dutch companies, knowledge institutes the new technical opportunities have led to and government authorities are market opportunities and sales. The Dutch working flat out on new technologies solar industry – present in great numbers and countless innovations in the field during the PV SEC – will demonstrate during of solar power. They are deeds and this event that they are able to transform answers appropriate for the global opportunities into business. push for power transition. They are deeds that will not just shape the There is a lot of positive news to report on future of the Netherlands, but the regarding knowledge, abilities and sales. Like future of the entire world. the funding of Solliance and the installation of the Solliance Industry Board, which you A future in which the Netherlands will can read all about in this magazine. hopefully lead with innovations. In which dependency on fossil fuels will decrease. There is also a part for the Dutch A future in which the Netherlands will government to play in the marketing of globally play a role of crucial importance. new technologies through the creation The potential is there. The Netherlands of an industry-friendly home market does not just have a knowledge institute and the stimulation of innovation. The in the Energieonderzoek Centrum Dutch government increasingly supports Nederland that enjoys global status, test and demonstration projects within it also has companies like OTB Solar, the field of solar power.
    [Show full text]
  • Spectral Beam Splitting for Solar Collectors a Photovoltaic-Thermal Receiver for Linear Solar Concentrators
    Spectral beam splitting for solar collectors A photovoltaic-thermal receiver for linear solar concentrators A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Ahmad Mojiri Master of Science in Engineering, University of New South Wales School of Aerospace Mechanical and Manufacturing Engineering College of Science Engineering and Health RMIT University July, 2016 Declaration I certify that except where due acknowledgement has been made, the work is that of the author alone; the work has not been submitted previously, in whole or in part, to qualify for any other academic award; the content of the thesis is the result of work which has been carried out since the official commencement date of the approved research program; any editorial work, paid or unpaid, carried out by a third party is acknowledged; and, ethics procedures and guidelines have been followed. Ahmad Mojiri July-2016 I would like to dedicate this thesis to my lovely wife, Aza, who unconditionally supported me throughout my PhD. Thank you Aza! Acknowledgements I would like to thank my senior supervisor, Prof. Gary Rosengarten, for his excellent leadership and invaluable technical support. I also thank my co-supervisor, Prof. Kourosh Kalantar-zadeh, for his generous contribution and kind help. I would like to acknowledge the support of Dr Cameron Stanley from RMIT University who contributed to this research by conducting CFD analysis, major support with the experimental rig set-up, uncertainty analysis of the experimental results, and proof reading of the manuscripts. I also acknowledge the support of Dr Vernie Everett, Ms Judith Harvey, Dr Elizabeth Thomsen and prof.
    [Show full text]
  • Solar Electric and Solar Thermal Energy: a Summary of Current Technologies
    Solar Electric and Solar Thermal Energy: A Summary of Current Technologies November, 2014 Tayyebatossadat P. Aghaei Research Associate, Global Energy Network Institute (GENI) [email protected] Under the supervision of and edited by Peter Meisen President, Global Energy Network Institute (GENI) www.geni.org [email protected] (619) 595-0139 1 Table of Contents Abstract ........................................................................................................................................... 5 1 Introduction ............................................................................................................................. 6 1.1 Nature of Solar Energy ........................................................................................................ 6 1.2 History of Solar Energy ....................................................................................................... 7 2 Large-scale Solar Thermal Technology Systems .................................................................... 9 2.1 Flat- plate Collector .................................................................................................................. 9 2.2 Concentrator Collector ............................................................................................................ 12 3 Non-power Plant Applications of Solar Energy .................................................................... 13 3.1 Solar Water Heater .................................................................................................................
    [Show full text]
  • Design and Strengthening of the Solar Energy Institute: Technical
    TECHNICAL ASSISTANCE COMPLETION REPORT Division: Energy Division Amount Approved: $225,000 TA 7846-UZB: Design and Strengthening of the Solar Revised Amount: $225,000 Energy Institute Executing Agency: Source of Funding: Amount Undisbursed: Amount Utilized: Ministry of Finance (MOF) Spanish Cooperation Fund $39,205 $185,795 for Technical Assistance1 TA Approval TA Signing Fielding of First TA Completion Date Actual: 30 Date: Date: Consultants: Original: 30 November 2011 November 2012 15 August 15 August September 2011 Account Closing Date Actual: 11 July 2011 2011 Original: 30 November 2011 2013 Description Uzbekistan has among the world’s highest energy and carbon intensities, both over 6 times the world average, requiring energy efficiency and renewable energy (RE). Hydropower is the only RE developed despite the huge potential, particularly that of solar power. Solar research expertise revolved around the Soviet era solar furnace. Modern solar applications and manufacturing were lacking, impeding widespread development. Following the 2010 Annual Meeting in Tashkent, the Government of Uzbekistan (GOU) requested ADB assistance to harness solar power. In May 2011, GOU and ADB signed a Memorandum of Understanding (MOU) to develop two solar technical assistance (TA) projects: this small-scale capacity development TA (S-CDTA) to design the Solar Energy Institute, which was later renamed as the International Solar Energy Institute (ISEI), and build solar capacity; and a $1.5 million policy and advisory TA (PATA 8008) approved in December 2011 to create the enabling policy environment and prepare solar projects. For both TAs, the Executing Agency (EA) was the Ministry of Finance, and the Implementing Agency (IA) was the Scientific Production Association on Solar Physics (Physics Sun).
    [Show full text]
  • Control of a Solar Furnace Using MPC with Integral Action
    Preprint, 11th IFAC Symposium on Dynamics and Control of Process Systems, including Biosystems June 6-8, 2016. NTNU, Trondheim, Norway Control of a Solar Furnace using MPC with Integral Action Bertinho A. Costa ∗ Jo˜ao M. Lemos ∗∗ Emmanuel Guillot ∗∗∗ ∗ INESC-ID/IST, University of Lisbon, Rua Alves Redol, 9 1000-029, Portugal (e-mail: [email protected]). ∗∗ INESC-ID/IST, University of Lisbon, Rua Alves Redol, 9 1000-029, Portugal (e-mail: [email protected]). ∗∗∗ CNRS-PROMES, 7 rue du Four Solaire, 66120 Font Romeu Odeillo, France (e-mail: [email protected]). Abstract: Solar furnaces are devices employed in high temperature material stress tests that use concentrated solar energy. This process has a nonlinear dynamics caused by a fourth power temperature term and by the nonlinear behavior of the shutter. Sun power variability due to weather conditions may affect the operation of a solar furnace if it is not compensated by adjusting the shutter aperture. The contribution of this paper is to explore and to evaluate the application of model predictive control with integral action to a nonlinear process. Off-line identification is employed to characterize the temperature dynamics. This methodology avoids the use of online adaptation mechanisms that may cause stability problems during temperature stress tests that may melt the material sample. The aim is to design a controller with a good performance, able to track the temperature cycling profile without overshooting to avoid melting the material sample. Active cooling is also explored to improve the temperature tracking during the decrease of the temperature profile.
    [Show full text]
  • The Department of Energy's Solar Industrial Program: New Ideas for American Industry
    SERl/TP-250-4256 • UC Category 234 • DE91002197 The Department of Energy's Solar Industrial Program: New Ideas for American Industry John V. Anderson Steven G. Hauser Richard J. Clyne S=�l��--�1 -� �=� Solar Energy Research Institute 1617 Cole Boulevard Golden, Colorado 80401-3393 A Division of Midwest Research Institute Operated for the U.S. Department of Energy um;ler Contract No. DE-AC02-83CH10093 July 1991 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, com­ pleteness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily con­ stitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Printed in the United States of America Available from: National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 Price: Microfiche A01 Printed Copy A02 Codes are used for pricing all publications. The code is determined by the number of pages in the publication. Information pertaining to the pricing codes can be found in the current issue of the following publications which are generally available in most libraries: Energy Research Abstracts (ERA); Govern­ ment Reports Announcements and Index ( GRA and I); Scientific and Technical Abstract Reports (STAR); and publication NTIS-PR-360 available from NTIS at the above address.
    [Show full text]