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Non-fusion applications of RF and microwave technology

Description: The processing of materials using rf and/or microwave power is a broad area that has grown significantly in the past few years. The authors have applied rf and microwave technology in the areas of ceramic sintering, plasma processing, and waste processing. The sintering of ceramics in the frequency range of 50 MHz-28 GHz has lead to unique material characteristics compared to materials that have been sintered conventionally. It has been demonstrated that sintering can be achieved in a variety of materials, including alumina, zirconia, silicon carbide, and boron carbide. In the area of plasma processing, progress has been made in the development and understanding of high density plasma sources, including inductively coupled plasma (ICP) sources. The effects of processing conditions on the ion energy distribution at the substrate surface (a critical processing issue) have been determined for a variety of process gases. The relationship between modeling and experiment is being established. Microwave technology has also been applied to the treatment of radioactive and chemical waste. The application of microwaves to the removal of contaminated concrete has been demonstrated. Details of these programs and other potential application areas are discussed.
Date: December 1, 1995
Creator: Caughman, J.B.O.; Baity, F.W.; Bigelow, T.S.; Gardner, W.L.; Hoffman, D.J.; Forrester, S.C. et al.
Partner: UNT Libraries Government Documents Department

Application of microwave solidification technology to radioactive waste

Description: The EPA has declared vitrification to be the Best Available Demonstrated Technology (BDAT) for High Level Radioactive Waste (40 CFR 268.42). Vitrification has been chosen as the method of choice for treating a number of radioactive residues and wastes in the DOE complex. Vitrification offers advantages of waste volume reduction, the ability to handle changing waste forms, and a stable, nonleachable final waste form. Microwave heating is a superior method for vitrification of radioactive wastes. Advantages of microwave heating include: (1) direct waste heating, eliminates need for electrodes, refractories and other consumables; (2) ``in-can`` processing allows for treatment of the material in its final container, (3) a mechanically simple system where the microwaves are generated away from the treatment area and transmitted to the treatment applicator by a wave guide, thus minimizing worker exposure to radiation; (4) easier equipment maintenance; and (5) a high degree of public acceptance.
Date: September 28, 1995
Creator: Harris, M.; Sprenger, G.; Roushey, B.; Fenner, G. & Nieweg, R.
Partner: UNT Libraries Government Documents Department

The use of solid-state NMR techniques for the analysis of water in coal and the effect of different coal drying techniques on the structure and reactivity of coal; Quarterly report, September 1--November 30, 1993

Description: For the research program reported here, different methods of drying are being investigated to determine if drying can be accomplished without destroying coal reactivity toward liquefaction. In an effort to understand the mechanism of water for enhancing coal liquefaction yield, the reactions of D{sub 2}O with the molecular constituents of coal during coal liquefaction are being investigated. This study involves the use of solution-state deuterium NMR, as well as, conventional solution-state {sup 1}H and {sup 13}C NMR analyses of the coal, and the coal liquids and residue from a coal liquefaction process. These D{sub 2}O transfer reactions will be conducted on coals which have been dried by various methods and rehydrated using D{sub 2}O and by successive exchange of H{sub 2}O associated with the coals with D{sub 2}O. The drying methods include thermal, microwave, and chemical dehydration of the coal. The overall objectives of this study are to develop a nuclear magnetic resonance (NMR) method for measuring the water in coal, to measure the changes in coal structure that occur during coal drying, to determine what effect water has on retrograde/condensation reactions, to determine the mechanism by which water may impact coal reactivity toward liquefaction, and to conduct D{sub 2}O exchange studies to ascertain the role of water in coal liquefaction. The objectives for this quarterly report period were (1) to measure the volumetric swelling ratio for thermally- and microwave-dried coals and (2) to conduct preliminary experiments concerning the exchange of water in coal with deuterium oxide (D{sub 2}O).
Date: December 31, 1993
Creator: Netzel, D.A.
Partner: UNT Libraries Government Documents Department

Use of a variable frequency source with a single-mode cavity to process ceramic filaments

Description: Rapid feedback control is needed for practical microwave processing of continuous ceramic oxide filaments to regulate the process temperature where the -dielectric properties of the filaments change rapidly with temperature. These dielectric changes can produce large rapid changes in the resonant frequency, the reflectivity, and the power density of the cavity. A broadband traveling wave tube (TWT) amplifier provides a highly versatile process control platform for filament processing. By comparing a RF signal from the cavity to a reference signal from the TWT, phase information can be used in a negative feedback loop to allow the oscillator to track the cavity frequency as it shifts due to the changing dielectric constant in the filaments being heated. By sampling the electric field level in the cavity with a detector, amplitude control can be done to maintain a constant absorbed power in a fiber tow, which is important for controlling the tow heating and temperature. This paper describes the design and testing of feedback controller with mullite rods in a single-mode TE{sub 10n} resonator driven by a commercial TWT.
Date: September 1, 1995
Creator: Vogt, G.J.; Regan, A.H.; Rohlev, A.S. & Curtin, M.T.
Partner: UNT Libraries Government Documents Department

Sintering of ceramics using low frequency rf power

Description: Sintering with low frequency rf power ({approximately}50 MHz) is a new technique with unique capabilities that has been used to sinter a variety of ceramic materials, including zirconia-toughened alumina, alumina, silicon carbide, and boron carbide. Processing with low frequencies offers many advantages compared to processing with conventional microwave frequencies (915 MHz and 2.45 GHz). Because of the longer wavelength, the rf electric field penetrates materials more than microwaves. This effect allows the processing of a wider variety of materials and allows for an increase in the physical size of the material being processed. In addition, the material is heated in a single mode cavity with a uniform electric field, which reduces the occurrence of hot-spot generation and thermal runaway effects. This technique has been used to sinter large crack-free alumina samples (3 inch square) to > 97% density. The sintering and/or annealing of a number of carbide materials has been demonstrated as well, including silicon carbide, boron carbide, tungsten carbide, and titanium carbide.
Date: July 1, 1995
Creator: Caughman, J.B.O.; Hoffman, D.J.; Baity, F.W.; Akerman, M.A.; Forrester, S.C. & Kass, M.D.
Partner: UNT Libraries Government Documents Department

Novel Direct Steelmaking by Combining Microwave, Electric Arc, and Exothermal Heating Technologies

Description: Steel is a basic material broadly used by perhaps every industry and individual. It is critical to our nation's economy and national security. Unfortunately, the American steel industry is losing competitiveness in the world steel production field. There is an urgent need to develop the next generation of steelmaking technology for the American steel industry. Direct steelmaking through the combination of microwave, electric arc, and exothermal heating is a revolutionary change from current steelmaking technology. This technology can produce molten steel directly from a shippable agglomerate, consisting of iron oxide fines, powdered coal, and ground limestone. This technology is projected to eliminate many current intermediate steelmaking steps including coking, pellet sintering, blast furnace (BF) ironmaking, and basic oxygen furnace (BOF) steelmaking. This technology has the potential to (a) save up to 45% of the energy consumed by conventional steelmaking; (b) dramatically reduce the emission of CO{sub 2}, SO{sub 2}, NO{sub x}, VOCs, fine particulates, and air toxics; (c) substantially reduce waste and emission control costs; (d) greatly lower capital cost; and (e) considerably reduce steel production costs. This technology is based on the unique capability of microwaves to rapidly heat steelmaking raw materials to elevated temperature, then rapidly reduce iron oxides to metal by volumetric heating. Microwave heating, augmented with electric arc and exothermal reactions, is capable of producing molten steel. This technology has the components necessary to establish the ''future'' domestic steel industry as a technology leader with a strong economically competitive position in world markets. The project goals were to assess the utilization of a new steelmaking technology for its potential to achieve better overall energy efficiency, minimize pollutants and wastes, lower capital and operating costs, and increase the competitiveness of the U.S. steel industry. The objectives associated with this goal were to (a) generate a solid base ...
Date: March 28, 2005
Creator: Huang, Dr. Xiaodi & Hwang, Dr. J. Y.
Partner: UNT Libraries Government Documents Department

Microwave heating for production of a glass bonded ceramic high-level waste form.

Description: Argonne National Laboratory has developed a ceramic waste form to immobilize the salt waste from electrometallurgical treatment of spent nuclear fuel. The process is being scaled up to produce bodies of 100 Kg or greater. With conventional heating, heat transfer through the starting powder mixture necessitates long process times. Coupling of 2.45 GHz radiation to the starting powders has been demonstrated. The radiation couples most strongly to the salt occluded zeolite powder. The results of these experiments suggest that this ceramic waste form could be produced using microwave heating alone, or by using microwave heating to augment conventional heating.
Date: July 30, 2002
Creator: O'Holleran, T. P.
Partner: UNT Libraries Government Documents Department

Decontamination of Radionuclides from Concrete During and After Thermal Treatment

Description: The objective was to clarify from the theoretical viewpoint the mechanical, diffusional, thermodynamic and electromagnetic aspects of the decontaminations problem, by means of developing a powerful computational model to evaluate the effect of a very rapid heating regime on the on the contaminated concrete walls or slabs. The practical objective was to assess the feasibility of the microwave heating scheme envisaged and determine its suitable parameters such as power and duration. This objective was complementary to, but separate from, the chemical and nuclear aspects of long-time processes that led to the contamination and various conceivable alternative methods of decontamination which were investigated by Dr. Brian Spalding of Oak Ridge National Laboratory, with whom the start-up phase of this project was coordinated.
Date: September 15, 1998
Creator: Bazant, Z. P.
Partner: UNT Libraries Government Documents Department

Microwave processing of ceramics

Description: This paper discusses the following topics on microwave processing of ceramics: Microwave-material interactions; anticipated advantage of microwave sintering; ceramic sintering; and ceramic joining. 24 refs., 4 figs. (LSP)
Date: January 1, 1989
Creator: Katz, J.D.
Partner: UNT Libraries Government Documents Department

Low density inorganic foams fabricated using microwaves

Description: The objective of our work was to determine if high temperature foams could be made using microwave heating; and if so, to investigate some of their properties. Several foams were made and their compressive strengths, tensile strengths and densities were determined. Foams were made of glass, metal-glass, glass-fiber, metal-glass-fiber, and fly ash. The microwave source used was a Litton model 1521 microwave oven which operated at 2.45 GHz and had an output of 700 watts.
Date: January 1, 1985
Creator: Meek, T.T.; Blake, R.D. & Gregory, T.G.
Partner: UNT Libraries Government Documents Department

Microwave sintering of alumina-SiC composites at 2. 45 and 60 GHz

Description: Composites of alumina-10 vol % silicon carbide whiskers were sintered to 70% of theoretical density using both 2.45 and 60 GHz microwave radiation. Further densification was inhibited by formation of a constrained network of whiskers. Alumina-10 vol % silicon carbide platelet composites were sintered to 94% of theoretical density with 2.45 GHz microwaves in less than 20 minutes. 4 refs., 11 figs.
Date: January 1, 1988
Creator: Katz, J.D.; Blake, R.D. & Petrovic, J.J.
Partner: UNT Libraries Government Documents Department

Precision timing and interlocks systems for FEL (free-electron laser) heating experiments on MTX (Microwave Tokamak Experiment)

Description: A new precision timing system has been installed on the Microwave Tokamak Experiment (MTX) at Lawrence Livermore National Laboratory (LLNL). The purpose of the system is to synchronize the tokamak's plasma discharge with a 140-GHz, 2-GW microwave pulse generated by a free-electron laser (FEL). The installation involved modifying the existing sequencer system and adding Digital delay generators, three in-house-designed CAMAC modules and other components. The system controls placement of the 30-ns FEL pulse during the MTX plasma discharge. It also provides precision triggers for the microwave plasma diagnostics. These triggers are distributed over 100-Mbit/s fiber-optic links. The MTX interlock system has been expanded to provide personnel safety during FEL experiments, to protect the FEL and related equipment, and to control the path of the FEL beam starting from the FEL's output, through the beam transport system, and into the tokamak. This paper describes how the existing MTX timing and interlocks systems were upgraded to accommodate these new FEL experiments. 4 refs., 4 figs.
Date: September 20, 1989
Creator: Petersen, D.E. (Lawrence Livermore National Lab., CA (USA))
Partner: UNT Libraries Government Documents Department

Microwave heating and current drive in tokamaks

Description: The use of powerful microwave sources provide unique opportunities for novel and efficient heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. Free- electron lasers and relativistic klystrons are new sources that have a number of technical advantages over conventional, lower-intensity sources; their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. This paper reports on modeling of absorption and current drive, in intense-pulse and quasilinear regimes, and on analysis of parametric instabilities and self-focusing. 16 refs., 2 figs.
Date: August 23, 1988
Creator: Cohen, B.I.; Cohen, R.H.; Kerbel, G.D.; Logan, B.G.; Matsuda, Y.; McCoy, M.G. et al.
Partner: UNT Libraries Government Documents Department

Operational characteristic of a compact microwave ion source

Description: A small microwave ion source has been fabricated from a quartz tube with one end enclosed by a two grid accelerator. The source is also enclosed by a cavity operated at a frequency of 2.45 GHz. Microwave power as high as 500 W can be coupled to the source plasma. The source has been operated with different geometries and for various gases in a cw mode. For hydrogen, ion current density of 200 mA/cm/sup 2/ with atomic ion species concentration as high as 80% has been extracted from the source. It has also been demonstrated that low energy oxygen ion beams (5 to 10 eV) can also be extracted from the source.
Date: March 1, 1986
Creator: Walther, S.R. & Leung, K.N.
Partner: UNT Libraries Government Documents Department

Microwave hybrid heating of alumina filaments

Description: Low loss oxide ceramics filaments are not readily heated to sintering temperatures (>900[degrees]C) by direct microwave heating at 2.45 GHz. Use of high power levels typically yields thermal runaway with catastrophic melting. In other studies, hybrid, or indirect, heating has been successfully applied to processing bulk oxide ceramics. In this work, commercial alumina-based filaments have been indirectly heated to 700[degrees]--900[degrees]C through a lossy carbon coating on the filament tow. Specific filaments can reach higher temperatures by direct coupling after preheating with a lossy coating. The results of microwave hybrid heating in a single mode TE[sub 102] cavity will be described for commercial alumina-based filaments.
Date: January 1, 1993
Creator: Vogt, G.J. & Unruh, W.P.
Partner: UNT Libraries Government Documents Department

Microwave sintering of nanophase ceramics without concomitant grain growth

Description: A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO[sub 2] as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.
Date: April 15, 1991
Creator: Eastman, J.A.; Sickafus, K.E. & Katz, J.D.
Partner: UNT Libraries Government Documents Department

Energy Efficient Microwave Hybrid Processing of Lime for Cement, Steel, and Glass Industries

Description: In this study, the microwave materials interactions were studied through dielectric property measurements, process modeling, and lab scale microwave hybrid calcination tests. Characterization and analysis were performed to evaluate material reactions and energy usage. Processing parameters for laboratory scale and larger scale calcining experiments were developed for MAT limestone calcination. Early stage equipment design concepts were developed, with a focus on microwave post heating treatment. The retrofitting of existing rotary calcine equipment in the lime industry was assessed and found to be feasible. Ceralink sought to address some of the major barriers to the uptake of MAT identified as the need for (1) team approach with end users, technology partners, and equipment manufacturers, (2) modeling that incorporates kiln materials and variations to the design of industrial microwave equipment. This project has furthered the commercialization effort of MAT by working closely with an industrial lime manufacturer to educate them regarding MAT, identifying equipment manufacturer to supply microwave equipment, and developing a sophisticated MAT modeling with WPI, the university partner. MAT was shown to enhance calcining through lower energy consumption and faster reaction rates compared to conventional processing. Laboratory testing concluded that a 23% reduction in energy was possible for calcining small batches (5kg). Scale-up testing indicated that the energy savings increased as a function of load size and 36% energy savings was demonstrated (22 kg). A sophisticated model was developed which combines simultaneous microwave and conventional heating. Continued development of this modeling software could be used for larger scale calcining simulations, which would be a beneficial low-cost tool for exploring equipment design prior to actual building. Based on these findings, estimates for production scale MAT calcining benefits were calculated, assuming uptake of MAT in the US lime industry. This estimate showed that 7.3 TBTU/year could be saved, with reduction of 270 ...
Date: February 10, 2012
Creator: Fall, Morgana L; Yakovlev, Vadim; Sahi, Catherine; Baranova, Inessa; Bowers, Johnney G & Esquenazi , Gibran L
Partner: UNT Libraries Government Documents Department

Use of polarimetry to measure the current profile in MTX

Description: It is possible in principle to measure the poloidal magnetic field profile, and hence, the profile of the plasma current measuring the change in the polarization of a sequence of microwave beams that pass through the plasma. Actual measurements of the plasma current profile would be very interesting in connection with Lower-Hybrid (or EC) current drive experiments since this would provide direct information on modification of the current profile by the application of rf power. A microwave polarimetry diagnostic on MTX as part of the microwave interferometer is being considered. This diagnostic would be constructed in collaboration with Neville Luhmann and Tony Peebles at UCLA. The diagnostic would utilize the multicord far-infrared interferometer which is designed to operate at a base wavelength of 0.185 mm. This paper reviews the understanding of the physics issues raised by this diagnostic, concurring with Luhmann and Peebles' conclusion that the polarimetry measurements would be easier at longer wavelengths. An increase of only a factor of 2 in the wavelength would make a substantial difference since the signal to be measured goes as lambda/sup 4/. Hence, in this paper operation at longer wavelengths (0.337 mm and 0.447 mm) in addition to operation at 0.119 and 0.185 mm will be considered.
Date: July 14, 1987
Creator: Nevins, W.M.; Hooper, E.B. & Bernstein, I.B.
Partner: UNT Libraries Government Documents Department

Advanced Industrial Materials (AIM) program. Compilation of project summaries and significant accomplishments FY 1996

Description: In many ways, the Advanced Industrial Materials (AIM) Program underwent a major transformation in Fiscal Year 1995 and these changes have continued to the present. When the Program was established in 1990 as the Advanced Industrial Concepts (AIC) Materials Program, the mission was to conduct applied research and development to bring materials and processing technologies from the knowledge derived from basic research to the maturity required for the end use sectors for commercialization. In 1995, the Office of Industrial Technologies (OIT) made radical changes in structure and procedures. All technology development was directed toward the seven {open_quotes}Vision Industries{close_quotes} that use about 80% of industrial energy and generated about 90% of industrial wastes. These are: (1) Aluminum; (2) Chemical; (3) Forest Products; (4) Glass; (5) Metal Casting; (6) Refineries; and (7) Steel. This report is a compilation of project summaries and significant accomplishments on materials.
Date: April 1, 1997
Partner: UNT Libraries Government Documents Department

Department of Energy treatment capabilities for greater-than-Class C low-level radioactive waste

Description: This report provides brief profiles for 26 low-level and high-level waste treatment capabilities available at the Idaho National Engineering Laboratory (INEL), Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Oak Ridge National Laboratory (ORNL), Pacific Northwest Laboratory (PNL), Rocky Flats Plant (RFP), Savannah River Site (SRS), and West Valley Demonstration Plant (WVDP). Six of the treatments have potential use for greater-than-Class C low-level waste (GTCC LLW). They include: (a) the glass ceramic process and (b) the Waste Experimental Reduction Facility incinerator at INEL; (c) the Super Compaction and Repackaging Facility and (d) microwave melting solidification at RFP; (e) the vitrification plant at SRS; and (f) the vitrification plant at WVDP. No individual treatment has the capability to treat all GTCC LLW streams. It is recommended that complete physical and chemical characterizations be performed for each GTCC waste stream, to permit using multiple treatments for GTCC LLW.
Date: January 1, 1995
Creator: Morrell, D.K. & Fischer, D.K.
Partner: UNT Libraries Government Documents Department

Hot electron confinement in a microwave heated spindle cusp

Description: The Plasma Research Laboratory at the University of Missouri-Columbia was established with awards from the McDonnel Douglas Foundation, ARMCO, Union Electric, Black and Vetch, Kansas City Power and Light, the National Science Foundation, and DOE. The Plasma Research Lab's major effort is the Missouri Magnetic Mirror (MMM or M{sup 3}) Project. The technical goals of MMM have been (1) Diagnostic Development, (2) Plasma Physics in the Cusp geometry, (3) plasma-wall interactions, (4) impurity effects in a steady-state plasma, and (5) Development of Diagnostics for use in harsh plasma processing environments. The other major goal of MMM has remained providing a facility for hands-on training in experimental plasma physics. The major experimental facility of MMM is the MMM Modified Experiment (M4X). Other research efforts in the Plasma Research Laboratory include small efforts in cold fusion, toroidal magnetic confinement, and inertial confinement and a potentially major effort in direct conversion of nuclear energy.
Date: August 1, 1991
Creator: Prelas, M.A.
Partner: UNT Libraries Government Documents Department

Power balance in ELMO Bumpy Torus: bulk electrons and ions in a 37 kW discharge

Description: The power balance of the bulk electrons and ions in discharges with 37 kW of applied microwave power in the ELMO Bumpy Torus (EBT) is examined in a zero-dimensional model using data on the intensity and linewidth of the molecular and atomic hydrogen emission. At least 60% of the applied power is ultimately dissipated by processes involving the neutral particles, including dissociation of molecules, ionization of and radiation from atoms, and heating of cold electrons produced during atomic ionization. The molecular influx rate and the density of atoms are used independently to determine the bulk electron particle confinement time, and an upper bound estimate is made of the diffusional power loss from the bulk plasma electrons. Parameters derived from the basic spectroscopic data presented in this paper include the neutral atom density 2 - 5x10/sup 10/ cm/sup -3/, incident molecular flux 3 - 5x10/sup 15/ cm/sup -2/s/sup -1/, bulk ion temperature approx. =3 eV, and particle confinement time <1.1 ms. The bulk electron energy confinement time is 0.7 ms or less in the standard operating regime. Published data on the nonthermal electron and ion populations in the plasma are used to evaluate approximately the overall energy flow in the discharge. 54 refs.
Date: October 1, 1985
Creator: McNeill, D.H.
Partner: UNT Libraries Government Documents Department

Microwave sintering of titanium diboride

Description: Titanium diboride was heated to high temperatures using microwaves. The highest temperature obtained was 2245/degree/C. Unfortunately, oxidation was a problem, especially at the higher temperatures, although an argon flush and a carbon getter were used. To completely stop oxidation, the oxygen potential must be below 10/sup /minus/18/ atmospheres. Using an argon flush and a carbon getter, titanium diboride was successfully densified to 82% of theoretical without measurable oxidation by heating with microwaves to 1860/degree/C. Density actually decreased upon reaching temperatures above 1860/degree/C due to void formation adjacent to the surface. Void formation is thought to be due to the formation of B/sub 2/O/sub 3/(g) which evolves rapidly above 1860/degree/C because of the loss of a TiO/sub 2/ protective film which melts at this temperature. 9 refs., 12 figs., 2 tabs.
Date: January 1, 1989
Creator: Katz, J.D.; Blake, R.D. & Scherer, C.P.
Partner: UNT Libraries Government Documents Department

Microwave processing of radioactive materials-I

Description: This paper is the first of two papers that reviews the major past and present applications of microwave energy for processing radioactive materials, with particular emphasis on processing radioactive wastes. Microwave heating occurs through the internal friction produced inside a dielectric material when its molecules vibrate in response to an oscillating microwave field. For this presentation, we shall focus on the two FCC-approved microwave frequencies for industrial, scientific, and medical use, 915 and 2450 MHz. Also, because of space limitations, we shall postpone addressing plasma processing of hazardous wastes using microwave energy until a later date. 13 refs., 4 figs.
Date: January 1, 1989
Creator: White, T.L. & Berry, J.B.
Partner: UNT Libraries Government Documents Department