The mechanism of explosive emission excitation in thermionic energy conversion processes

Science.gov (United States)

Bulyga, A. V.

A study has been made of the mechanism of explosive electron emission in vacuum thermionic converters induced by thermionic currents in the case of the anomalous Richardson effect. The latter is associated with a spotted emitting surface and temperature fluctuations. In order to account for one of the components of the electrode potential difference, it is proposed that allowance be made for the difference between the polarization signal velocity in a dense metal electron gas and that in the electron-ion gas of the electrode gap. Ways to achieve explosive emission in real thermionic converters are discussed.

SP-100 thermionic technology program annual integrated technical progress report for the period ending September 30, 1984

International Nuclear Information System (INIS)

Holland, J.W.

1984-11-01

The thermionic technology program addresses the feasibility issues of a seven-year-life thermionic fuel element (TFE) for the SP-100 Thermionic Reactor Space Power System. These issues relate to the extension of TFE lifetime from three to seven years, one of the SP-100 requirements. The technology to support three-year lifetimes was demonstrated in the earlier TFE development program conducted in the late-1960s and 1970s. Primary life-limiting factors were recognized to be thermionic emitter dimensional increases due to swelling of the nuclear fuel and electrical structural damage from fast neutrons. The 1984-85 technology program is investigating the fueled emitter and insulator lifetime issues, both experimentally and analytically. The goal is to analytically project the lifetime of the fueled emitter and insulator and to experimentally verify these projection methods. In 1984, the efforts were largely devoted to the design and building of fueled emitters for irradiation in 1985, validation of fuel-emitter models, development of irradiation-resistant metal-ceramic seal and sheath insulator, modeling of insulator lifetime, and development of wide-spread, high-performance thermionic converters

The Thermionic System Evaluation Test (TSET): Descriptions, limitations, and the involvement of the space nuclear power community

International Nuclear Information System (INIS)

Morris, D.B.

1993-01-01

Project and test planning for the Thermionic System Evaluation Test (TSET) Project began in August 1990. Since the formalization of the contract agreement two years ago, the TOPAZ-II testing hardware was delivered in May 1992. In the months since the delivery of the test hardware, Russians and Americans working side-by-side installed the equipment and are preparing to begin testing in early 1993. The procurement of the Russian TOPAZ-II unfueled thermionic space nuclear power system (SNP) provides a unique opportunity to understand a complete thermionic system and enhances the possibility for further study of this type of power conversion for space applications. This paper will describe the program and test article, facility and test article limitations, and how the government and industry are encouraged to be involved in the program

Thermionic emission from monolayer graphene, sheath formation and its feasibility towards thermionic converters

Science.gov (United States)

Misra, Shikha; Upadhyay Kahaly, M.; Mishra, S. K.

2017-02-01

A formalism describing the thermionic emission from a single layer graphene sheet operating at a finite temperature and the consequent formation of the thermionic sheath in its proximity has been established. The formulation takes account of two dimensional densities of state configuration, Fermi-Dirac (f-d) statistics of the electron energy distribution, Fowler's treatment of electron emission, and Poisson's equation. The thermionic current estimates based on the present analysis is found to be in reasonably good agreement with experimental observations (Zhu et al., Nano Res. 07, 1 (2014)). The analysis has further been simplified for the case where f-d statistics of an electron energy distribution converges to Maxwellian distribution. By using this formulation, the steady state sheath features, viz., spatial dependence of the surface potential and electron density structure in the thermionic sheath are derived and illustrated graphically for graphene parameters; the electron density in the sheath is seen to diminish within ˜10 s of Debye lengths. By utilizing the graphene based cathode in configuring a thermionic converter (TC), an appropriate operating regime in achieving the efficient energy conversion has been identified. A TC configured with the graphene based cathode (operating at ˜1200 K/work function 4.74 V) along with the metallic anode (operating at ˜400 K/ work function 2.0 V) is predicted to display ˜56% of the input thermal flux into the electrical energy, which infers approximately ˜84% of the Carnot efficiency.

Radioisotope thermionic converters for space applications

International Nuclear Information System (INIS)

Miskolczy, G.; Lieb, D.P.

1990-01-01

The recent history of radioisotope thermionics is reviewed, with emphasis on the U.S. programs, and the prospects for the future are assessed. In radioisotope thermionic converters the emitter heat is generated by the decay of a radioactive isotope. The thermionic converter emitter is mounted directly on a capsule containing the isotope. The rest of the capsule is generally insulated to reduce thermal loss. The development of isotope-fueled thermionic power systems for space application has been pursued since the late 1950's. The U.S. effort was concentrated on modular systems with alpha emitters as the isotope heat source. In the SNAP-13 program, the heat sources were Cerium isotopes and each module produced about 100 watts. The converters were planar diodes and the capsule was insulated with multi-foil insulation

High Efficiency Thermionics (HET-IV) and Converter Advancement (CAP) programs. Final reports

Energy Technology Data Exchange (ETDEWEB)

Geller, C.B.; Murray, C.S.; Riley, D.R. [Bettis Atomic Power Lab., West Mifflin, PA (United States); Desplat, J.L.; Hansen, L.K.; Hatch, G.L.; McVey, J.B.; Rasor, N.S. [Rasor Associates, Inc., Sunnyvale, CA (United States)

1996-04-01

This report contains the final report of the High Efficiency Thermionics (HET-IV) Program, Attachment A, performed at Rasor Associates, Inc. (RAI); and the final report of the Converter Advancement Program (CAP), performed at the Bettis Atomic Power Laboratory, Attachment B. The phenomenology of cesium-oxygen thermionic converters was elucidated in these programs, and the factors that had prevented the achievement of stable, enhanced cesium-oxygen converter performance for the previous thirty years were identified. Based on these discoveries, cesium-oxygen vapor sources were developed that achieved stable performance with factor-of-two improvements in power density and thermal efficiency, relative to conventional, cesium-only ignited mode thermionic converters. Key achievements of the HET-IV/CAP programs are as follows: a new technique for measuring minute traces of oxygen in cesium atmospheres; the determination of the proper range of oxygen partial pressures for optimum converter performance--10{sup {minus}7} to 10{sup {minus}9} torr; the discovery, and analysis of the cesium-oxygen liquid migration and compositional segregation phenomena; the successful use of capillary forces to contain the migration phenomenon; the use of differential heating to control compositional segregation, and induce vapor circulation; the development of mechanically and chemically stable, porous reservoir structures; the development of precise, in situ oxygen charging methods; stable improvements in emitter performance, up to effective emitter bare work functions of 5.4 eV; stable improvements in barrier index, to value below 1.8 Volts; the development of detailed microscopic models for cesium-oxygen reservoir dynamics and collector work function behavior; and the discovery of new relationships between electrode geometry and Schock Instability.

Hybrid thermionic-photovoltaic converter

Energy Technology Data Exchange (ETDEWEB)

Datas, A. [Instituto de Energía Solar, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

2016-04-04

A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligible electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ∼1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.

Thermionic energy conversion heat - electric power; Termojonisk energiomvandling vaerme-elektrisk energi

Energy Technology Data Exchange (ETDEWEB)

Holmlid, L; Svensson, R [Gothenburg Univ. and Chalmers Univ. of Technology (Sweden)

1993-09-15

Research and development related to Thermionic Energy Converters (TEC) in Holland and Sweden is directed towards terrestrial applications, while the development work in Russia and the US primarily is directed towards thermionic nuclear reactor for use in space. We have during the project continued our work on the utilization of the so called Rydberg matter in converters. Our patented construction has very good (low) values of the barrier index (figure of merit for the converter), probably the lowest ones ever measured. International patents have been applied for as well. We can summarize the achievements of the project such that solutions to practically all the problems related to the inner function of thermionic converters have been found. During this year a large number of studies have been carried out concerning the properties of the Rydberg matter in the TEC, and related to the highly excited states of Cs which exist in the TEC, partially in cooperation with an American research company. An international conference within the TEC field has been arranged in Gothenburg. Two Ph.D. theses are also under completion within the project

Isotopic Thermionic Generator

International Nuclear Information System (INIS)

Clemot, M.; Devin, B.; Durand, J.P.

1967-01-01

This report describes the general design of a thermionic direct conversion space generator. The power source used is a radioisotope. Two radioisotopes are considered: Pu 238 and Cm 244. The system is made up of a heat pipe concentrating the thermal flux from the isotope to the emitter, and of a second heat pipe evacuating the waste heat from the collector to the outer wall used as radiating panel. Calculations are given in the particular case of a 100 electrical watts output power. (authors) [fr

High power densities from high-temperature material interactions. [in thermionic energy conversion and metallic fluid heat pipes

Science.gov (United States)

Morris, J. F.

1981-01-01

Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs), offering unique advantages in terrestrial and space energy processing by virtue of operating on working-fluid vaporization/condensation cycles that accept great thermal power densities at high temperatures, share complex materials problems. Simplified equations are presented that verify and solve such problems, suggesting the possibility of cost-effective applications in the near term for TEC and MFHP devices. Among the problems discussed are: the limitation of alkali-metal corrosion, protection against hot external gases, external and internal vaporization, interfacial reactions and diffusion, expansion coefficient matching, and creep deformation.

Photon enhanced thermionic emission

Science.gov (United States)

Schwede, Jared; Melosh, Nicholas; Shen, Zhixun

2014-10-07

Photon Enhanced Thermionic Emission (PETE) is exploited to provide improved efficiency for radiant energy conversion. A hot (greater than 200.degree. C.) semiconductor cathode is illuminated such that it emits electrons. Because the cathode is hot, significantly more electrons are emitted than would be emitted from a room temperature (or colder) cathode under the same illumination conditions. As a result of this increased electron emission, the energy conversion efficiency can be significantly increased relative to a conventional photovoltaic device. In PETE, the cathode electrons can be (and typically are) thermalized with respect to the cathode. As a result, PETE does not rely on emission of non-thermalized electrons, and is significantly easier to implement than hot-carrier emission approaches.

Solid-State Thermionic Nuclear Power for Megawatt Propulsion, Planetary Surface and Commercial Power Project

Data.gov (United States)

National Aeronautics and Space Administration — Thermionic (TI) power conversion is a promising technology first investigated for power conversion in the 1960’s, and of renewed interest due to modern...

Development of a high temperature solar receiver for high-efficient thermionic conversion systems; Fukugo netsuden henkan system yo chokoon taiyo junetsuki no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Umeoka, T; Naito, H; Yugami, H; Arashi, H [Tohoku University, Sendai (Japan). Faculty of Engineering

1996-10-27

For thermionic conversion systems (TIC) using concentrated sunlight as heat source, the newly developed solar receiver was tested. Concentrated sunlight aims at the inner surface of the cavity type solar receiver. The emitter of TIC installed in the rear of the solar receiver is uniformly heated over 1700K by thermal radiation from the rear of the solar receiver, emitting thermion. Electric power is generated by collecting the thermion by collector. Mo is used as emitter material, however, because of poor heat absorption of Mo, high-absorptive TiC is used for heat absorption surface to heat Mo by thermal conduction from high-temperature TiC. Functionally gradient material (FGM) with an intermediate layer of gradient TiC/Mo ratios between TiC and Mo is used as emitter material. The emitter is thus uniformly heated at high temperatures of 1723{plus_minus}12K. As a result, the developed solar receiver is applicable to heat the emitter of TIC. Heat flux measurement at the graphite cavity clarified that cavity temperature of as high as 1780K and heat flow of 50W/cm{sup 2} are obtained at 4.7kW in input. 6 figs.

Beta Radiation Enhanced Thermionic Emission from Diamond Thin Films

Directory of Open Access Journals (Sweden)

Alex Croot

2017-11-01

Full Text Available Diamond-based thermionic emission devices could provide a means to produce clean and renewable energy through direct heat-to-electrical energy conversion. Hindering progress of the technology are the thermionic output current and threshold temperature of the emitter cathode. In this report, we study the effects on thermionic emission caused by in situ exposure of the diamond cathode to beta radiation. Nitrogen-doped diamond thin films were grown by microwave plasma chemical vapor deposition on molybdenum substrates. The hydrogen-terminated nanocrystalline diamond was studied using a vacuum diode setup with a 63Ni beta radiation source-embedded anode, which produced a 2.7-fold increase in emission current compared to a 59Ni-embedded control. The emission threshold temperature was also examined to further assess the enhancement of thermionic emission, with 63Ni lowering the threshold temperature by an average of 58 ± 11 °C compared to the 59Ni control. Various mechanisms for the enhancement are discussed, with a satisfactory explanation remaining elusive. Nevertheless, one possibility is discussed involving excitation of preexisting conduction band electrons that may skew their energy distribution toward higher energies.

Heat-pipe thermionic reactor concept

DEFF Research Database (Denmark)

Storm Pedersen, E.

1967-01-01

Main components are reactor core, heat pipe, thermionic converter, secondary cooling system, and waste heat radiator; thermal power generated in reactor core is transported by heat pipes to thermionic converters located outside reactor core behind radiation shield; thermionic emitters are in direct...

Advantages and implications of U233 fueled thermionic space power energy conversion

International Nuclear Information System (INIS)

Terrell, C.W.

1992-01-01

In this paper two recent analyses are reported which demonstrate advantages of a U233 fueled thermionic fuel element (TFE) compared to 93 w/o U235, and that application (mission) has broad latitude in how space power reactor systems could or should be optimized. A reference thermionic reactor system was selected to provide the basis for the fuel comparisons. Both oxide and metal fuel forms were compared. Of special interest was to estimate the efficiencies of the four fuel forms to produce electrical power. A figure of merit (FOM) was defined which is directly proportional to the electrical average electrical power produced is proportional to the electrical power produced per unit uranium mass. In a TFE the average electrical power produced is proportional to the emitter surface area (Esa), hence the ratio Esa/Mu was selected as the FOM. Results indicate that the choice of fuel type and form leads to wide variations in critical and system masses FOM values, and system total power

Photophysics of fullerenes: Thermionic emission

International Nuclear Information System (INIS)

Compton, R.N.; Tuinman, A.A.; Huang, J.

1996-01-01

Multiphoton ionization of fullerenes using long-pulse length lasers occurs mainly through vibrational autoionization. In many cases the laser ionization can be described as thermionic in analogy to the boiling off of electrons from a filament. Thermionic emission manifests itself as a delayed emission of electrons following pulsed laser excitation. Klots has employed quasiequilibrium theory to calculate rate constants for thermionic emission from fullerenes which seem to quantitatively account for the observed delayed emission times and the measured electron energy distributions. The theory of Klots also accounts for the thermionic emission of C 60 excited by a low power CW Argon Ion laser. Recently Klots and Compton have reviewed the evidence for thermionic emission from small aggregates where mention was also made of experiments designed to determine the effects of externally applied electric fields on thermionic emission rates. The authors have measured the fullerene ion intensity as a function of the applied electric field and normalized this signal to that produced by single photon ionization of an atom in order to correct for all collection efficiency artifacts. The increase in fullerene ion signal relative to that of Cs + is attributed to field enhanced thermionic emission. From the slope of the Schottky plot they obtain a temperature of approximately 1,000 K. This temperature is comparable to but smaller than that estimated from measurements of the electron kinetic energies. This result for field enhanced thermionic emission is discussed further by Klots and Compton. Thermionic emission from neutral clusters has long been known for autodetachment from highly excited negative ions. Similarly, electron attachment to C 60 in the energy range from 8 to 12 eV results in C 60 anions with lifetimes in the range of microseconds. Quasiequilibrium theory (QET) calculations are in reasonable accord with these measurements

Photophysics of fullerenes: Thermionic emission

Energy Technology Data Exchange (ETDEWEB)

Compton, R.N. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States); Tuinman, A.A. [Univ. of Tennessee, Knoxville, TN (United States); Huang, J. [Ames Lab., IA (United States)

1996-09-01

Multiphoton ionization of fullerenes using long-pulse length lasers occurs mainly through vibrational autoionization. In many cases the laser ionization can be described as thermionic in analogy to the boiling off of electrons from a filament. Thermionic emission manifests itself as a delayed emission of electrons following pulsed laser excitation. Klots has employed quasiequilibrium theory to calculate rate constants for thermionic emission from fullerenes which seem to quantitatively account for the observed delayed emission times and the measured electron energy distributions. The theory of Klots also accounts for the thermionic emission of C{sub 60} excited by a low power CW Argon Ion laser. Recently Klots and Compton have reviewed the evidence for thermionic emission from small aggregates where mention was also made of experiments designed to determine the effects of externally applied electric fields on thermionic emission rates. The authors have measured the fullerene ion intensity as a function of the applied electric field and normalized this signal to that produced by single photon ionization of an atom in order to correct for all collection efficiency artifacts. The increase in fullerene ion signal relative to that of Cs{sup +} is attributed to field enhanced thermionic emission. From the slope of the Schottky plot they obtain a temperature of approximately 1,000 K. This temperature is comparable to but smaller than that estimated from measurements of the electron kinetic energies. This result for field enhanced thermionic emission is discussed further by Klots and Compton. Thermionic emission from neutral clusters has long been known for autodetachment from highly excited negative ions. Similarly, electron attachment to C{sub 60} in the energy range from 8 to 12 eV results in C{sub 60} anions with lifetimes in the range of microseconds. Quasiequilibrium theory (QET) calculations are in reasonable accord with these measurements.

Advanced thermionic reactor systems design code

International Nuclear Information System (INIS)

Lewis, B.R.; Pawlowski, R.A.; Greek, K.J.; Klein, A.C.

1991-01-01

An overall systems design code is under development to model an advanced in-core thermionic nuclear reactor system for space applications at power levels of 10 to 50 kWe. The design code is written in an object-oriented programming environment that allows the use of a series of design modules, each of which is responsible for the determination of specific system parameters. The code modules include a neutronics and core criticality module, a core thermal hydraulics module, a thermionic fuel element performance module, a radiation shielding module, a module for waste heat transfer and rejection, and modules for power conditioning and control. The neutronics and core criticality module determines critical core size, core lifetime, and shutdown margins using the criticality calculation capability of the Monte Carlo Neutron and Photon Transport Code System (MCNP). The remaining modules utilize results of the MCNP analysis along with FORTRAN programming to predict the overall system performance

Thermionic system evaluated test (TSET) facility description

Science.gov (United States)

Fairchild, Jerry F.; Koonmen, James P.; Thome, Frank V.

1992-01-01

A consortium of US agencies are involved in the Thermionic System Evaluation Test (TSET) which is being supported by the Strategic Defense Initiative Organization (SDIO). The project is a ground test of an unfueled Soviet TOPAZ-II in-core thermionic space reactor powered by electrical heat. It is part of the United States' national thermionic space nuclear power program. It will be tested in Albuquerque, New Mexico at the New Mexico Engineering Research Institute complex by the Phillips Laboratoty, Sandia National Laboratories, Los Alamos National Laboratory, and the University of New Mexico. One of TSET's many objectives is to demonstrate that the US can operate and test a complete space nuclear power system, in the electrical heater configuration, at a low cost. Great efforts have been made to help reduce facility costs during the first phase of this project. These costs include structural, mechanical, and electrical modifications to the existing facility as well as the installation of additional emergency systems to mitigate the effects of utility power losses and alkali metal fires.

System modeling and reactor design studies of the Advanced Thermionic Initiative space nuclear reactor

International Nuclear Information System (INIS)

Lee, H.H.; Abdul-Hamid, S.; Klein, A.C.

1996-01-01

In-core thermionic space reactor design concepts that operate at a nominal power output range of 20 to 50 kW(electric) are described. Details of the neutronic, thermionic, thermal hydraulics, and shielding performance are presented. Because of the strong absorption of thermal neutrons by natural tungsten and the large amount of natural tungsten within the reactor core, two designs are considered. An overall system design code has been developed at Oregon State University to model advanced in-core thermionic energy conversion-based nuclear reactor systems for space applications. The results show that the driverless single-cell Advanced Thermionic Initiative (ATI) configuration, which does not have driver fuel rods, proved to be more efficient than the driven core, which has driver rods. The results also show that the inclusion of the true axial and radial power distribution decrease the overall conversion efficiency. The flattening of the radial power distribution by three different methods would lead to a higher efficiency. The results show that only one TFE works at the optimum emitter temperature; all other TFEs are off the optimum performance and result in a 40% decrease of the efficiency of the overall system. The true axial profile is significantly different as there is a considerable amount of neutron leakage out of the top and bottom of the reactor. The analysis reveals that the axial power profile actually has a chopped cosine shape. For this axial profile, the reactor core overall efficiency for the driverless ATI reactor version is found to be 5.84% with a total electrical power of 21.92 kW(electric). By considering the true axial power profile instead of the uniform power profile, each TFE loses ∼80 W(electric)

Isotopic Thermionic Generator; Generateur thermoionique isotopique

Energy Technology Data Exchange (ETDEWEB)

Clemot, M; Devin, B; Durand, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

This report describes the general design of a thermionic direct conversion space generator. The power source used is a radioisotope. Two radioisotopes are considered: Pu 238 and Cm 244. The system is made up of a heat pipe concentrating the thermal flux from the isotope to the emitter, and of a second heat pipe evacuating the waste heat from the collector to the outer wall used as radiating panel. Calculations are given in the particular case of a 100 electrical watts output power. (authors) [French] Ce rapport decrit la structure d'un generateur spatial d'electricite a conversion directe du type thermoionique. La source d'energie est un radioisotope. Deux isotopes sont envisages: le Pu 238 et le Cm 244. Le systeme comporte pour l'emetteur un caloduc concentreur de flux thermique et pour le collecteur, un caloduc evacuateur vers l'enveloppe du generateur utilise, en panneau rayonnant. Les calculs ont ete conduits dans le cas particulier d'une puissance convertie de 100 watts electriques. (auteurs)

High-efficiency AlxGa1-xAs/GaAs cathode for photon-enhanced thermionic emission solar energy converters

Science.gov (United States)

Feng, Cheng; Zhang, Yijun; Qian, Yunsheng; Wang, Ziheng; Liu, Jian; Chang, Benkang; Shi, Feng; Jiao, Gangcheng

2018-04-01

A theoretical emission model for AlxGa1-xAs/GaAs cathode with complex structure based on photon-enhanced thermionic emission is developed by utilizing one-dimensional steady-state continuity equations. The cathode structure comprises a graded-composition AlxGa1-xAs window layer and an exponential-doping GaAs absorber layer. In the deduced model, the physical properties changing with the Al composition are taken into consideration. Simulated current-voltage characteristics are presented and some important factors affecting the conversion efficiency are also illustrated. Compared with the graded-composition and uniform-doping cathode structure, and the uniform-composition and uniform-doping cathode structure, the graded-composition and exponential-doping cathode structure can effectively improve the conversion efficiency, which is ascribed to the twofold built-in electric fields. More strikingly, this graded bandgap structure is especially suitable for photon-enhanced thermionic emission devices since a higher conversion efficiency can be achieved at a lower temperature.

Thermionics basic principles of electronics

CERN Document Server

Jenkins, J; Ashhurst, W

2013-01-01

Basic Principles of Electronics, Volume I : Thermionics serves as a textbook for students in physics. It focuses on thermionic devices. The book covers topics on electron dynamics, electron emission, and the themionic vacuum diode and triode. Power amplifiers, oscillators, and electronic measuring equipment are studied as well. The text will be of great use to physics and electronics students, and inventors.

High temperature cogeneration with thermionic burners

International Nuclear Information System (INIS)

Fitzpatrick, G.O.; Britt, E.J.; Dick, R.S.

1981-01-01

The thermionic cogeneration combustor was conceived to meet industrial requirements for high-temperature direct heat, typically in the form of gas at temperatures from 800 to 1900 K, while at the same time supplying electricity. The thermionic combustor is entirely self-contained, with heat from the combustion region absorbed by the emitters of thermionic converters to be converted to electric power and the high-temperature reject heat from the converters used to preheat the air used for combustion. Depending on the temperature of the process gas produced, energy savings of around 10% with respect to that used to produce the same amount of electricity and heat without cogeneration are possible with present technology, and savings of up to 20% may be possible with advanced converters. Possible thermionic combustor designs currently under investigation include a configuration in which heat is collected by heat pipes lining the periphery of the combustion region, and a fire-tube converter in which combustion occurs within the cylindrical emitter of each converter. Preliminary component tests of these designs have been encouraging

High temperature cogeneration with thermionic burners

Science.gov (United States)

Fitzpatrick, G. O.; Britt, E. J.; Dick, R. S.

The thermionic cogeneration combustor was conceived to meet industrial requirements for high-temperature direct heat, typically in the form of gas at temperatures from 800 to 1900 K, while at the same time supplying electricity. The thermionic combustor is entirely self-contained, with heat from the combustion region absorbed by the emitters of thermionic converters to be converted to electric power and the high-temperature reject heat from the converters used to preheat the air used for combustion. Depending on the temperature of the process gas produced, energy savings of around 10% with respect to that used to produce the same amount of electricity and heat without cogeneration are possible with present technology, and savings of up to 20% may be possible with advanced converters. Possible thermionic combustor designs currently under investigation include a configuration in which heat is collected by heat pipes lining the periphery of the combustion region, and a fire-tube converter in which combustion occurs within the cylindrical emitter of each converter. Preliminary component tests of these designs have been encouraging.

Comparative assessment of out-of-core nuclear thermionic power systems

International Nuclear Information System (INIS)

Estabrook, W.C.; Koenig, D.R.; Prickett, W.Z.

1975-01-01

The hardware selections available for fabrication of a nuclear electric propulsion stage for planetary exploration were explored. The investigation was centered around a heat-pipe-cooled, fast-spectrum nuclear reactor for an out-of-core power conversion system with sufficient detail for comparison with the in-core system studies completed previously. A survey of competing power conversion systems still indicated that the modular reliability of thermionic converters makes them the desirable choice to provide the 240-kWe end-of-life power for at least 20,000 full power hours. The electrical energy will be used to operate a number of mercury ion bombardment thrusters with a specific impulse in the range of about 4,000-5,000 seconds. (Author)

Thermionic detector with multiple layered ionization source

International Nuclear Information System (INIS)

Patterson, P. L.

1985-01-01

Method and apparatus for analyzing specific chemical substances in a gaseous environment comprises a thermionic source formed of multiple layers of ceramic material composition, an electrical current instrumentality for heating the thermionic source to operating temperatures in the range of 100 0 C. to 1000 0 C., an instrumentality for exposing the surface of the thermionic source to contact with the specific chemical substances for the purpose of forming gas phase ionization of the substances by a process of electrical charge emission from the surface, a collector electrode disposed adjacent to the thermiomic source, an instrumentality for biasing the thermionic source at an electrical potential which causes the gas phase ions to move toward the collector, and an instrumentality for measuring the ion current arriving at the collector. The thermionic source is constructed of a metallic heater element molded inside a sub-layer of hardened ceramic cement material impregnated with a metallic compound additive which is non-corrosive to the heater element during operation. The sub-layer is further covered by a surface-layer formed of hardened ceramic cement material impregnated with an alkali metal compound in a manner that eliminates corrosive contact of the alkali compounds with the heater element. The sub-layer further protects the heater element from contact with gas environments which may be corrosive. The specific ionization of different chemical substances is varied over a wide range by changing the composition and temperature of the thermionic source, and by changing the composition of the gas environment

Thermionic nuclear reactor with internal heat distribution and multiple duct cooling

Science.gov (United States)

Fisher, C.R.; Perry, L.W. Jr.

1975-11-01

A Thermionic Nuclear Reactor is described having multiple ribbon-like coolant ducts passing through the core, intertwined among the thermionic fuel elements to provide independent cooling paths. Heat pipes are disposed in the core between and adjacent to the thermionic fuel elements and the ribbon ducting, for the purpose of more uniformly distributing the heat of fission among the thermionic fuel elements and the ducts.

Thermionic cogeneration burner design

Science.gov (United States)

Miskolczy, G.; Goodale, D.; Moffat, A. L.; Morgan, D. T.

Since thermionic converters receive heat at very high temperatures (approximately 1800 K) and reject heat at moderately high temperatures (approximately 800 K), they are useful for cogeneration applications involving high temperature processes. The electric power from thermionic converters is produced as a high amperage, low-voltage direct current. An ideal cogeneration application would be to utilize the reject heat at the collector temperature and the electricity without power conditioning. A cogeneration application in the edible oil industry fulfills both of these requirements since both direct heat and hydrogen gas are required in the hydrogenation of the oils. In this application, the low-voltage direct current would be used in a hydrogen electrolyzer.

Thermionic reactors for space nuclear power

Science.gov (United States)

Homeyer, W. G.; Merrill, M. H.; Holland, J. W.; Fisher, C. R.; Allen, D. T.

1985-01-01

Thermionic reactor designs for a variety of space power applications spanning the range from 5 kWe to 3 MWe are described. In all of these reactors, nuclear heat is converted directly to electrical energy in thermionic fuel elements (TFEs). A circulating reactor coolant carries heat from the core of TFEs directly to a heat rejection radiator system. The recent design of a thermionic reactor to meet the SP-100 requirements is emphasized. Design studies of reactors at other power levels show that the same TFE can be used over a broad range in power, and that design modifications can extend the range to many megawatts. The design of the SP-100 TFE is similar to that of TFEs operated successfully in test reactors, but with design improvements to extend the operating lifetime to seven years.

A new concept of thermionic converter

International Nuclear Information System (INIS)

Musa, G.

1978-10-01

The parameters of a new type of thermionic converter which has a number of concentric electrodes, is computed. The obtained theoretical efficiency of this new type of converter is nearly the efficiency of the ideal thermionic converter. The obtained results are explained by the reduction of the radiation loss from the emitter due to the electrode configuration. Efficiencies as high as 20% are expected from this type of converter now in construction. (author)

Development of a thermionic-reactor space-power system. Final summary report

International Nuclear Information System (INIS)

1973-01-01

Initial experimental work led to the award of the first AEC thermionic contract on May 1, 1962, for the development of fission heated thermionic cells with an operating life of 10,000 hours or more. Two types of converters were fabricated: (1) electrically heated, and (2) fission heated where the fuel was either uranium carbide or uranium oxide. Competition between GGA and GE was climaxed on July 1, 1970 by the award to GGA of a contract to develop an in-core thermionic reactor. This report is divided into the following: thermionic research, materials technology, thermionic fuel element development, reactor technology, and systems technology

Thermionic phenomena the collected works of Irving Langmuir

CERN Document Server

Suits, C Guy

1961-01-01

Thermionic Phenomena is the third volume of the series entitled The Collected Works of Irving Langmuir. This volume compiles articles written during the 1920's and early 1930's, the period when the science of thermionics is beginning to be of importance. This text is divided into two parts. The first part discusses vacuum pumps, specifically examining the effect of space charge and residual gases on thermionic currents in high vacuum. This part also explains fundamental phenomena in electron tubes having tungsten cathodes and the use of high-power vacuum tubes. The second part of this text loo

Work function and surface stability of tungsten-based thermionic electron emission cathodes

Science.gov (United States)

Jacobs, Ryan; Morgan, Dane; Booske, John

2017-11-01

Materials that exhibit a low work function and therefore easily emit electrons into vacuum form the basis of electronic devices used in applications ranging from satellite communications to thermionic energy conversion. W-Ba-O is the canonical materials system that functions as the thermionic electron emitter commercially used in a range of high-power electron devices. However, the work functions, surface stability, and kinetic characteristics of a polycrystalline W emitter surface are still not well understood or characterized. In this study, we examined the work function and surface stability of the eight lowest index surfaces of the W-Ba-O system using density functional theory methods. We found that under the typical thermionic cathode operating conditions of high temperature and low oxygen partial pressure, the most stable surface adsorbates are Ba-O species with compositions in the range of Ba0.125O-Ba0.25O per surface W atom, with O passivating all dangling W bonds and Ba creating work function-lowering surface dipoles. Wulff construction analysis reveals that the presence of O and Ba significantly alters the surface energetics and changes the proportions of surface facets present under equilibrium conditions. Analysis of previously published data on W sintering kinetics suggests that fine W particles in the size range of 100-500 nm may be at or near equilibrium during cathode synthesis and thus may exhibit surface orientation fractions well described by the calculated Wulff construction.

HEAT Sensor: Harsh Environment Adaptable Thermionic Sensor

Energy Technology Data Exchange (ETDEWEB)

Limb, Scott J. [Palo Alto Research Center, Palo Alto, CA (United States)

2016-05-31

This document is the final report for the “HARSH ENVIRONMENT ADAPTABLE THERMIONIC SENSOR” project under NETL’s Crosscutting contract DE-FE0013062. This report addresses sensors that can be made with thermionic thin films along with the required high temperature hermetic packaging process. These sensors can be placed in harsh high temperature environments and potentially be wireless and self-powered.

Negative space charge effects in photon-enhanced thermionic emission solar converters

International Nuclear Information System (INIS)

Segev, G.; Weisman, D.; Rosenwaks, Y.; Kribus, A.

2015-01-01

In thermionic energy converters, electrons in the gap between electrodes form a negative space charge and inhibit the emission of additional electrons, causing a significant reduction in conversion efficiency. However, in Photon Enhanced Thermionic Emission (PETE) solar energy converters, electrons that are reflected by the electric field in the gap return to the cathode with energy above the conduction band minimum. These electrons first occupy the conduction band from which they can be reemitted. This form of electron recycling makes PETE converters less susceptible to negative space charge loss. While the negative space charge effect was studied extensively in thermionic converters, modeling its effect in PETE converters does not account for important issues such as this form of electron recycling, nor the cathode thermal energy balance. Here, we investigate the space charge effect in PETE solar converters accounting for electron recycling, with full coupling of the cathode and gap models, and addressing conservation of both electric and thermal energy. The analysis shows that the negative space charge loss is lower than previously reported, allowing somewhat larger gaps compared to previous predictions. For a converter with a specific gap, there is an optimal solar flux concentration. The optimal solar flux concentration, the cathode temperature, and the efficiency all increase with smaller gaps. For example, for a gap of 3 μm the maximum efficiency is 38% and the optimal flux concentration is 628, while for a gap of 5 μm the maximum efficiency is 31% and optimal flux concentration is 163

Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating. [coal combustion product environments

Science.gov (United States)

Morris, J. F.

1980-01-01

Applied research-and-technology (ART) work reveals that optimal thermionic energy conversion (TEC) with approximately 1000 K to approximately 1100 K collectors is possible using well established tungsten electrodes. Such TEC with 1800 K emitters could approach 26.6% efficiency at 27.4 W/sq cm with approximately 1000 K collectors and 21.7% at 22.6 W/sq cm with approximately 1100 K collectors. These performances require 1.5 and 1.7 eV collector work functions (not the 1 eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approximately 0.9 to approximately 6 torr cesium pressures with 1600 K to 1900 K emitters. Because higher heat-rejection temperatures for TEC allow greater collector work functions, interelectrode loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the TEC-ART approaches to reduced interelectrode losses. These solutions will provide very effective TEC to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal and to use it well.

Thermionic integrated circuit technology for high power space applications

International Nuclear Information System (INIS)

Yadavalli, S.R.

1984-01-01

Thermionic triode and integrated circuit technology is in its infancy and it is emerging. The Thermionic triode can operate at relatively high voltages (up to 2000V) and at least tens of amperes. These devices, including their use in integrated circuitry, operate at high temperatures (800 0 C) and are very tolerant to nuclear and other radiations. These properties can be very useful in large space power applications such as that represented by the SP-100 system which uses a nuclear reactor. This paper presents an assessment of the application of thermionic integrated circuitry with space nuclear power system technology. A comparison is made with conventional semiconductor circuitry considering a dissipative shunt regulator for SP-100 type nuclear power system rated at 100 kW. The particular advantages of thermionic circuitry are significant reductions in size and mass of heat dissipation and radiation shield subsystems

A50-kW(el) solar energy thermionic power generator for spacecraft

International Nuclear Information System (INIS)

Sahin, S.

1978-01-01

The technical limits of thermionic reactors in space craft and the potentials of solar energy thermionic converters are discussed. The technical design of a solar energy thermionic generator for 50 kW(el) as a secondary energy source in unmanned space craft is presented. (GG) [de

Nanoscale Materials and Architectures for Energy Conversion

Energy Technology Data Exchange (ETDEWEB)

Grulke, Eric A. [Univ. of Kentucky, Lexington, KY (United States); Sunkara, Mahendra K. [University of Louisville, KY (United States)

2011-05-25

The Kentucky EPSCoR Program supported an inter-university, multidisciplinary energy-related research cluster studying nanomaterials for converting solar radiation and residual thermal energy to electrical energy and hydrogen. It created a collaborative center of excellence based on research expertise in nanomaterials, architectures, and their synthesis. The project strengthened and improved the collaboration between the University of Louisville, the University of Kentucky, and NREL. The cluster hired a new faculty member for ultra-fast transient spectroscopy, and enabled the mentoring of one research scientist, two postdoctoral scholars and ten graduate students. Work was accomplished with three focused cluster projects: organic and photoelectrochemical solar cells, solar fuels, and thermionic energy conversion.

Biomass Thermochemical Conversion Program: 1986 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1987-01-01

Wood and crop residues constitute a vast majority of the biomass feedstocks available for conversion, and thermochemical processes are well suited for conversion of these materials. Thermochemical conversion processes can generate a variety of products such as gasoline hydrocarbon fuels, natural gas substitutes, or heat energy for electric power generation. The US Department of Energy is sponsoring research on biomass conversion technologies through its Biomass Thermochemical Conversion Program. Pacific Northwest Laboratory has been designated the Technical Field Management Office for the Biomass Thermochemical Conversion Program with overall responsibility for the Program. This report briefly describes the Thermochemical Conversion Program structure and summarizes the activities and major accomplishments during fiscal year 1986. 88 refs., 31 figs., 5 tabs.

Biomass thermochemical conversion program: 1987 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1988-01-01

The objective of the Biomass Thermochemical Conversion Program is to generate a base of scientific data and conversion process information that will lead to establishment of cost-effective processes for conversion of biomass resources into clean fuels. To accomplish this objective, in fiscal year 1987 the Thermochemical Conversion Program sponsored research activities in the following four areas: Liquid Hydrocarbon Fuels Technology; Gasification Technology; Direct Combustion Technology; Program Support Activities. In this report an overview of the Thermochemical Conversion Program is presented. Specific research projects are then described. Major accomplishments for 1987 are summarized.

Transient and steady-state analyses of an electrically heated Topaz-II Thermionic Fuel Element

International Nuclear Information System (INIS)

El-Genk, M.S.; Xue, H.

1992-01-01

Transient and steady-state analyses of electrically heated, Thermionic Fuel Elements (TFEs) for Topaz-II space power system are performed. The calculated emitter and collector temperatures, load electric power and conversion efficiency are in good agreement with reported data. In this paper the effects or Cs pressure, thermal power input, and load resistance on the steady-state performance of the TFE are also investigated. In addition, the thermal response of the ZrH moderator during a startup transient and following a change in the thermal power input is examined

Biomass thermochemical conversion program. 1985 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1986-01-01

Wood and crop residues constitute a vast majority of the biomass feedstocks available for conversion, and thermochemical processes are well suited for conversion of these materials. The US Department of Energy (DOE) is sponsoring research on this conversion technology for renewable energy through its Biomass Thermochemical Conversion Program. The Program is part of DOE's Biofuels and Municipal Waste Technology Division, Office of Renewable Technologies. This report briefly describes the Thermochemical Conversion Program structure and summarizes the activities and major accomplishments during fiscal year 1985. 32 figs., 4 tabs.

U.S. Domestic Reactor Conversion Programs

International Nuclear Information System (INIS)

Woolstenhulme, Eric

2008-01-01

The Conversion Projects Include: the revision of the facilities safety basis documents and supporting analysis, the fabrication of new LEU fuel, the change-out of the reactor core, and the removal of the used HEU fuel (by INL University Fuels Program or DOE-NE). The major entities involved are: the U.S. Nuclear Regulatory Commission, the University reactor department, the fuel and hardware fabricators, the Spent fuel receipt facilities, the Spent fuel shipping services, and the U.S. Department of Energy and their subcontractors. Three major Reactor Conversion Program milestones have been accomplished since 2006: the conversion of the TRIGA reactor at Texas A and M University Nuclear Science Center, the conversion of the University of Florida Training Reactor, and the conversion of the Purdue University Reactor. Four Reactor Conversion Program milestones yet to be accomplished in 2008 and 2009: the Washington State University Nuclear Radiation Center reactor, the Oregon State University TRIGA Reactor, the University of Wisconsin Nuclear Reactor, and the Neutron Radiography Reactor Facility. NNSA is committed to doing things cheaper, better, smarter, safer through a 'Lessons Learned' process. The conversion team assessed each major activity grouping: Project Initiation, Conversion Proposal Development, Fuel Fabrication and Hardware, Core Conversion, and Spent Nuclear Fuel Removal. Issues were identified and recommendations were given

A NEW THERMIONIC RF ELECTRON GUN FOR SYNCHROTRON LIGHT SOURCES

Energy Technology Data Exchange (ETDEWEB)

Kutsaev, Sergey; Agustsson, R.; Hartzell, J; Murokh, A.; Nassiri, A.; Savin, E.; Smirnov, A.V.; Smirnov, A. Yu; Sun, Y.; Verma, A; Waldschmidt, Geoff; Zholents, A.

2017-06-02

A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source at Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity and report the progress towards high power tests of the cathode assembly of the new gun.

Thermodynamics of photon-enhanced thermionic emission solar cells

International Nuclear Information System (INIS)

Reck, Kasper; Hansen, Ole

2014-01-01

Photon-enhanced thermionic emission (PETE) cells in which direct photon energy as well as thermal energy can be harvested have recently been suggested as a new candidate for high efficiency solar cells. Here, we present an analytic thermodynamical model for evaluation of the efficiency of PETE solar cells including an analysis of the entropy production due to thermionic emission of general validity. The model is applied to find the maximum efficiency of a PETE cell for given cathode and anode work functions and temperatures

The direct conversion of heat into electricity in reactors

International Nuclear Information System (INIS)

Devin, B.; Bliaux, J.; Lesueur, R.

1964-01-01

The direct conversion of heat into electricity by thermionic emission in an atomic reactor has been studied with the triple aim of its utilisation: as an energy source for a space device, at the head of a conventional conversion system in power installations, or finally in association with the thermoelectric conversion in very low power installations. The laboratory experiments were mainly orientated towards the electron extraction of metals and compounds and their behaviour at high temperatures. Converters furnishing up to 50 amps at 0. 4 volts with an efficiency close to 10 p. 100 have been constructed in the laboratory; the emitters were heated by electron bombardment and were composed of tungsten covered with an uranium carbide deposit or molybdenum covered with cesium. The main aspects of the coupling between the converter and the reactor have been covered from the point of view of electronics: the influence of the mismatching of the load on the temperature of the emitter and the influence of thermal flux density on the temperature of the emitter and the stability of the converter. Converters using uranium carbide as the electron emitter have been tested in reactors. Tests have been made under dynamic conditions in order to determine the dynamic characteristics. The load matching curves have been constructed and the overall performances of several cells coupled in such a way as to form a reactor rod have been deduced. This information is fundamental to the design of a control system for a thermionic conversion reactor. The problems associated with the reliability of thermionic converters connected in series in the same reactor rod have been examined theoretically. Finally, the absorption isotherms have been drawn at the ambient temperatures for krypton and xenon on activated carbon with the aim of investigating the escape of fission products in a converter. (author) [fr

Materials for thermionic energy converters

NARCIS (Netherlands)

Wolff, L.R.; Hermans, J.M.; Adriaansen, J.K.M.; Gubbels, G.H.M.; Vincenzini, P.

1987-01-01

This paper deals with the design and construction of a combustion heated Thermionic Energy Converter (TEC). Main components of this TEC are: 1. A ''Hot Shell'' protecting the TEC from the combustion environment 2. A ''Ceramic Seal'' electrically insulating the emitter from the collector 3. A

Thermionic refrigeration at CNT-CNT junctions

Science.gov (United States)

Li, C.; Pipe, K. P.

2016-10-01

Monte Carlo (MC) simulation is used to study carrier energy relaxation following thermionic emission at the junction of two van der Waals bonded single-walled carbon nanotubes (SWCNTs). An energy-dependent transmission probability gives rise to energy filtering at the junction, which is predicted to increase the average electron transport energy by as much as 0.115 eV, leading to an effective Seebeck coefficient of 386 μV/K. MC results predict a long energy relaxation length (˜8 μm) for hot electrons crossing the junction into the barrier SWCNT. For SWCNTs of optimal length, an analytical transport model is used to show that thermionic cooling can outweigh parasitic heat conduction due to high SWCNT thermal conductivity, leading to a significant cooling capacity (2.4 × 106 W/cm2).

Thermionics. A bibliography with abstracts. Search period covered: 1970--Apr 1975. [190 references

Energy Technology Data Exchange (ETDEWEB)

Grooms, D.W.

1975-04-01

Research on thermionic power generation, power plant design, converter design, and basic research on thermionic materials are cited in the bibliography. Spacecraft applications are included. (Contains 190 abstracts).

Photocathode operation of a thermionic RF gun

International Nuclear Information System (INIS)

Thorin, S.; Cutic, N.; Lindau, F.; Werin, S.; Curbis, F.

2009-01-01

The thermionic RF gun using a BaO cathode at the MAX-lab linac injector has been successfully commissioned for additional operation as a photocathode gun. By retaining the BaO cathode, lowering the temperature below thermal emission and illuminating it with a UV (263 nm) 9 ps laser pulse a reduced emittance and enhanced emission control has been achieved. Measurements show a normalised emittance of 5.5 mm mrad at 200 pC charge and a maximum quantum efficiency of 1.1x10 -4 . The gun is now routinely switched between storage ring injections in thermionic mode and providing a beam for the MAX-lab test FEL in photocathode mode.

maximum conversion efficiency of thermionic heat to electricity

African Journals Online (AJOL)

DJFLEX

Dushman constant ... Several attempts on the direct conversion of heat to electricity ... The net current density in the system is equal to jE – jC , which gets over the potential barrier. jE and jC are given by the Richardson-. Dushman equation as. │. ⌋.

Graphene for thermoelectronic solar energy conversion

Science.gov (United States)

De, Dilip K.; Olukunle, Olawole C.

2017-08-01

Graphene is a high temperature material which can stand temperature as high as 4600 K in vacuum. Even though its work function is high (4.6 eV) the thermionic emission current density at such temperature is very high. Graphene is a wonderful material whose work function can be engineered as desired. Kwon et al41 reported a chemical approach to reduce work function of graphene using K2CO3, Li2CO3, Rb2CO3, Cs2CO3. The work functions are reported to be 3.7 eV, 3.8 eV, 3.5 eV and 3.4 eV. Even though they did not report the high temperature tolerance of such alkali metal carbonate doped graphene, their works open a great promise for use of pure graphene and doped graphene as emitter (cathode) and collector (anode) in a solar thermionic energy converter. This paper discusses the dynamics of solar energy conversion to electrical energy using thermionic energy converter with graphene as emitter and collector. We have considered parabolic mirror concentrator to focus solar energy onto the emitter to achieve temperature around 4300 K. Our theoretical calculations and the modelling show that efficiency as high as 55% can easily be achieved if space-charge problem can be reduced and the collector can be cooled to certain proper temperature. We have discussed methods of controlling the associated space-charge problems. Richardson-Dushman equation modified by the authors have been used in this modelling. Such solar energy conversion would reduce the dependence on silicon solar panel and has great potential for future applications.

Energy conversion options for ARIES-III - A conceptual D-3He tokamak reactor

International Nuclear Information System (INIS)

Santarius, J.F.; Blanchard, J.P.; Emmert, G.A.; Sviatoslavsky, I.N.; Wittenberg, L.J.; Ghoneim, N.M.; Hasan, M.Z.; Mau, T.K.; Greenspan, E.; Herring, J.S.; Kernbichler, W.; Klein, A.C.; Miley, G.H.; Miller, R.L.; Peng, Y.K.M.

1989-01-01

The potential for highly efficient conversion of fusion power to electricity provides one motivation for investigating D- 3 He fusion reactors. This stems from: (1) the large fraction of D- 3 He power produced in the forms of charged particles and synchrotron radiation which are amenable to direct conversion, and (2) the low neutron fluence and lack of tritium breeding constraints, which increase design flexibility. The design team for a conceptual D- 3 He tokamak reactor, ARIES-III, has investigated numerous energy conversion options at a scoping level in attempting to realize high efficiency. The energy conversion systems have been studied in the context of their use on one or more of three versions of a D- 3 He tokamak: a first stability regime device, a second stability regime device, and a spherical torus. The set of energy conversion options investigated includes bootstrap current conversion, compression-expansion cycles, direct electrodynamic conversion, electrostatic direct conversion, internal electric generator, liquid metal heat engine blanket, liquid metal MHD, plasma MHD, radiation boiler, scrape-off layer thermoelectric, synchrotron radiation conversion by rectennas, synchrotron radiation conversion by thermal cycles, thermionic/AMTEC/thermal systems, and traveling wave conversion. The original set of options is briefly discussed, and those selected for further study are described in more detail. The four selected are liquid metal MHD, plasma MHD, rectenna conversion, and direct electrodynamic conversion. Thermionic energy conversion is being considered, and some options may require a thermal cycle in parallel or series. 17 refs., 3 figs., 1 tab

Progress in radiation immune thermionic integrated circuits

International Nuclear Information System (INIS)

Lynn, D.K.; McCormick, J.B.

1985-08-01

This report describes the results of a program directed at evaluating the thermionic integrated circuit (TIC) technology for applicability to military systems. Previous programs under the sponsorship of the Department of Energy, Office of Basic Energy Sciences, have developed an initial TIC technology base and demonstrated operation in high-temperature and high-radiation environments. The program described in this report has two parts: (1) a technical portion in which experiments and analyses were conducted to refine perceptions of near-term as well as ultimate performance levels of the TIC technology and (2) an applications portion in which the technical conclusions were to be evaluated against potential military applications. This report draws several conclusions that strongly suggest that (1) useful radiation-hard/high-temperature operable integrated circuits can be developed using the TIC technology; (2) because of their ability to survive and operate in hostile environments, a variety of potential military applications have been projected for this technology; and (3) based on the above two conclusions, an aggressive TIC development program should be initiated to provide the designers of future systems with integrated circuits and devices with the unique features of the TICs

Progress in radiation immune thermionic integrated circuits

Energy Technology Data Exchange (ETDEWEB)

Lynn, D.K.; McCormick, J.B. (comps.)

1985-08-01

This report describes the results of a program directed at evaluating the thermionic integrated circuit (TIC) technology for applicability to military systems. Previous programs under the sponsorship of the Department of Energy, Office of Basic Energy Sciences, have developed an initial TIC technology base and demonstrated operation in high-temperature and high-radiation environments. The program described in this report has two parts: (1) a technical portion in which experiments and analyses were conducted to refine perceptions of near-term as well as ultimate performance levels of the TIC technology and (2) an applications portion in which the technical conclusions were to be evaluated against potential military applications. This report draws several conclusions that strongly suggest that (1) useful radiation-hard/high-temperature operable integrated circuits can be developed using the TIC technology; (2) because of their ability to survive and operate in hostile environments, a variety of potential military applications have been projected for this technology; and (3) based on the above two conclusions, an aggressive TIC development program should be initiated to provide the designers of future systems with integrated circuits and devices with the unique features of the TICs.

Thermionic integrated circuits: electronics for hostile environments

International Nuclear Information System (INIS)

Lynn, D.K.; McCormick, J.B.; MacRoberts, M.D.J.; Wilde, D.K.; Dooley, G.R.; Brown, D.R.

1985-01-01

Thermionic integrated circuits combine vacuum tube technology with integrated circuit techniques to form integrated vacuum triode circuits. These circuits are capable of extended operation in both high-temperature and high-radiation environments

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1981-10-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

CID thermionic gun system

International Nuclear Information System (INIS)

Koontz, R.F.

1982-01-01

A new high-current thermionic gun has been installed on the CID injector at SLAC and brought into operation. The gun and pulser system generate three nanosecond pulses of about six amps peak which, when bunched in the subharmonic buncher system, produce in excess of 10 11 electrons in a single S-band accelerated bunch. Preliminary operation of the gun is described, and details of the avalanche cathode drive pulser are presented

Development of a thermionic magnicon amplifier at 11.4 GHz. Technical progress report, 16 May 1994--31 December 1995

International Nuclear Information System (INIS)

Gold, S.H.; Fliflet, A.W.; Manheimer, W.M.

1995-01-01

This is a progress report on a four-year research program entitled 'Development of a Thermionic Magnicon Amplifier at 11.4 GHz', which is under way in the Plasma Physics Division of the Naval Research Laboratory (NRL) under Interagency Agreement DE-AI02-94ER40681. This report covers the period 16 May 1994 through 31 December 1995. The magnicon is an advanced microwave tube with potential application to future high gradient linear accelerators such as TeV colliders. Under this program, NRL plans to build and test a thermionic magnicon amplifier tube powered by a 500 kV, 200 A, 10 Hz modulator with a 1 μsec pulse. However, the experiments that were carried out during the period covered by this report were driven by a single-shot Marx generator, and the electron beam was produced from a graphite plasma cathode

New features of the MAX IV thermionic pre-injector

Energy Technology Data Exchange (ETDEWEB)

Andersson, J., E-mail: joel.andersson@maxiv.lu.se; Olsson, D., E-mail: david.olsson@maxiv.lu.se; Curbis, F.; Malmgren, L.; Werin, S.

2017-05-21

The MAX IV facility in Lund, Sweden consists of two storage rings for production of synchrotron radiation. The smaller 1.5 GeV ring is presently under construction, while the larger 3 GeV ring is being commissioned. Both rings will be operating with top-up injections from a full-energy injector. During injection, the electron beam is first delivered to the main injector from a thermionic pre-injector which consists of a thermionic RF gun, a chopper system, and an energy filter. In order to reduce losses of high-energy electrons along the injector and in the rings, the electron beam provided by the thermionic pre-injector should have the correct time structure and energy distribution. In this paper, the design of the MAX IV thermionic pre-injector with all its sub components is presented. The electron beam delivered by the pre-injector and its dependence on parameters such as optics, cathode temperature, and RF power are studied. Measurements are here compared with simulation results obtained by particle tracking and electromagnetic codes. The chopper system is described in detail, and different driving schemes that optimize the injection efficiency for the two storage rings are investigated. During operation, it was discovered that the structure of the beam delivered by the gun is affected by mode beating between the accelerating and a low-order mode. This mode beating is also studied in detail. Finally, initial measurements of the electron beam delivered to the 3 GeV ring during commissioning are presented.

Thermionic Power Cell To Harness Heat Energies for Geothermal Applications

Science.gov (United States)

Manohara, Harish; Mojarradi, Mohammad; Greer, Harold F.

2011-01-01

A unit thermionic power cell (TPC) concept has been developed that converts natural heat found in high-temperature environments (460 to 700 C) into electrical power for in situ instruments and electronics. Thermionic emission of electrons occurs when an emitter filament is heated to gwhite hot h temperatures (>1,000 C) allowing electrons to overcome the potential barrier and emit into the vacuum. These electrons are then collected by an anode, and transported to the external circuit for energy storage.

Dexter - A one-dimensional code for calculating thermionic performance of long converters.

Science.gov (United States)

Sawyer, C. D.

1971-01-01

This paper describes a versatile code for computing the coupled thermionic electric-thermal performance of long thermionic converters in which the temperature and voltage variations cannot be neglected. The code is capable of accounting for a variety of external electrical connection schemes, coolant flow paths and converter failures by partial shorting. Example problem solutions are given.

Evaluation of precision in measurements of uranium isotope ratio by thermionic mass spectrometry

International Nuclear Information System (INIS)

Moraes, N.M.P. de; Rodrigues, C.

1977-01-01

The parameters which affect the precision and accuracy of uranium isotopic ratios measurements by thermionic mass spectrometry are discussed. A statistical designed program for the analysis of the internal and external variances are presented. It was done an application of this statistical methods, in order to get mass discrimination factor, and its standard mean deviation, by using some results already published for 235 U/ 238 U ratio in NBS uranium samples, and natural uranium [pt

DEXTER: A one-dimensional code for calculating thermionic performance of long converters

Science.gov (United States)

Sawyer, C. D.

1971-01-01

A versatile code is described for computing the coupled thermionic electric-thermal performance of long thermionic converters in which the temperature and voltage variations cannot be neglected. The code is capable of accounting for a variety of external electrical connection schemes, coolant flow paths and converter failures by partial shorting. Example problem solutions are included along with a user's manual.

Evidence for cluster shape effects on the kinetic energy spectrum in thermionic emission.

Science.gov (United States)

Calvo, F; Lépine, F; Baguenard, B; Pagliarulo, F; Concina, B; Bordas, C; Parneix, P

2007-11-28

Experimental kinetic energy release distributions obtained for the thermionic emission from C(n) (-) clusters, 10theory, these different features are analyzed and interpreted as the consequence of contrasting shapes in the daughter clusters; linear and nonlinear isomers have clearly distinct signatures. These results provide a novel indirect structural probe for atomic clusters associated with their thermionic emission spectra.

On thermionic emission from plasma-facing components in tokamak-relevant conditions.

Czech Academy of Sciences Publication Activity Database

Komm, Michael; Ratynskaia, S.; Tolias, P.; Cavalier, Jordan; Dejarnac, Renaud; Gunn, J. P.; Podolník, Aleš

2017-01-01

Roč. 59, č. 9 (2017), č. článku 094002. ISSN 0741-3335 R&D Projects: GA ČR(CZ) GA16-14228S; GA MŠk(CZ) 8D15001 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : thermionic * PIC * tungsten * tokamak * thermionic emission * plasma facing components * particle-in-cell Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.392, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6587/aa78c4/pdf

Energy Conversion and Storage Program

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1992-03-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Thermionic combustor application to combined gas and steam turbine power plants

Science.gov (United States)

Miskolczy, G.; Wang, C. C.; Lieb, D. P.; Margulies, A. E.; Fusegni, L. J.; Lovell, B. J.

A design for the insertion of thermionic converters into the wall of a conventional combustor to produce electricity in a topping cycle is described, and a study for applications in gas and steam generators of 70 and 30 MW is evaluated for engineering and economic feasibility. Waste heat from the thermionic elements is used to preheat the combustor air; the heat absorbed by the elements plus further quenching of the exhaust gases with ammonia is projected to reduce NO(x) emissions to acceptable levels. Schematics, flow diagrams, and components of a computer model for cost projections are provided. It was found that temperatures around the emitters must be maintained above 1,600 K, with maximum efficiency and allowable temperature at 1,800 K, while collectors generate maximally at 950 K, with a corresponding work function of 1.5 eV. Cost sensitive studies indicate an installed price of $475/kW for the topping cycle, with improvements in thermionic converter characteristics bringing the cost to $375/kW at a busbar figure of 500 mills/kWh.

Thermionic combustor application to combined gas and steam turbine power plants

International Nuclear Information System (INIS)

Miskolczy, G.; Wang, C.C.; Lieb, D.P.

1981-01-01

A design for the insertion of thermionic converters into the wall of a conventional combustor to produce electricity in a topping cycle is described, and a study for applications in gas and steam generators of 70 and 30 MW is evaluated for engineering and economic feasibility. Waste heat from the thermionic elements is used to preheat the combustor air, the heat absorbed by the elements plus further quenching of the exhaust gases with ammonia is projected to reduce NO(x) emissions to acceptable levels. Schematics, flow diagrams, and components of a computer model for cost projections are provided. It was found that temperatures around the emitters must be maintained above 1,600 K, with maximum efficiency and allowable temperature at 1,800 K, while collectors generate maximally at 950 K, with a corresponding work function of 1.5 eV. Cost sensitive studies indicate an installed price of $475/kW for the topping cycle, with improvements in thermionic converter characteristics bringing the cost to $375/kW at a busbar figure of 500 mills/kWh

Biomass Thermochemical Conversion Program. 1984 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1985-01-01

The objective of the program is to generate scientific data and conversion process information that will lead to establishment of cost-effective process for converting biomass resources into clean fuels. The goal of the program is to develop the data base for biomass thermal conversion by investigating the fundamental aspects of conversion technologies and by exploring those parameters that are critical to the conversion processes. The research activities can be divided into: (1) gasification technology; (2) liquid fuels technology; (3) direct combustion technology; and (4) program support activities. These activities are described in detail in this report. Outstanding accomplishments during fiscal year 1984 include: (1) successful operation of 3-MW combustor/gas turbine system; (2) successful extended term operation of an indirectly heated, dual bed gasifier for producing medium-Btu gas; (3) determination that oxygen requirements for medium-Btu gasification of biomass in a pressurized, fluidized bed gasifier are low; (4) established interdependence of temperature and residence times on biomass pyrolysis oil yields; and (5) determination of preliminary technical feasibility of thermally gasifying high moisture biomass feedstocks. A bibliography of 1984 publications is included. 26 figs., 1 tab.

The HOR core conversion program development and licensing experiences

International Nuclear Information System (INIS)

Vries, J.W. de; Gibcus, H.P.M.; Leege, P.F.A. de

1997-01-01

This paper deals with the experiences in the development of a fuel conversion program for a 2 MW university type research reactor, the HOR. It gives an overview of the technical and administrative aspects concerning the fuel conversion program development since the eighties, including the safety review and licensing process. The overall final safety report was submitted in 1995, together with the environmental impact report, and a licence application was submitted accordingly. The licence permitting the conversion was issued in 1996, coming into force at the beginning of this year, although an appeal case is still pending. At the moment the necessary preparations for starting the actual conversion of the HOR are made. The general program characteristics are addressed. (author)

Cesium-plasma-conductivity enhancement in the advanced thermionic energy converter. Final report

International Nuclear Information System (INIS)

Manikopoulos, C.N.

Two methods of plasma conductivity enhancement in a cesium vapor thermionic energy converter have been studied. The first involved resonance photoabsorption of several cesium lines and the second utilized cesium plasma sustenance by application of microwave power. An extensive study of ionization processes in a cesium discharge in the presence of resonance ionization was made. Calculations were made of expected percentage excitation levels for several cesium resonance transitions for different values of neutral density and temperature as well as incident radiation power levels. The results of some of these computations were tabulated. Several ionization schemes were considered. A number of cesium transitions were investigated in the range of 799 to 870 nanometers for four different cesium reservoir temperatures, 467, 511, 550 and 591 K. The related absorption coefficients of the radiation lines in the plasma were deduced and tabulated. The resulting plasma conductivity increase was recorded and the associated ionization enhancement was deduced. A microwave cavity was built where the emitter and collector of a simple thermionic converter made up two of the cavity walls and resonant microwave power was externally applied. The I-V characteristics of the thermionic converter were studied under several microwave power levels in the range of 0 to 2 watts. Significant shifts to higher currents were observed as the microwave power levels were raised. In conclusion, both methods show promise as auxiliary ionization mechanisms for the thermionic energy converter, especially at low emitter temperatures

Thermodynamics of photon-enhanced thermionic emission solar cells

DEFF Research Database (Denmark)

Reck, Kasper; Hansen, Ole

2014-01-01

Photon-enhanced thermionic emission (PETE) cells in which direct photon energy as well as thermal energy can be harvested have recently been suggested as a new candidate for high efficiency solar cells. Here, we present an analytic thermodynamical model for evaluation of the efficiency of PETE...

Thermionic emission of cermets made of refractory carbides

International Nuclear Information System (INIS)

Samsonow, G.W.; Bogomol, I.W.; Ochremtschuk, L.N.; Podtschernjajewa, I.A.; Fomenko, W.S.

1975-01-01

In order to improve the resistance to thermal variations of refractory carbides having good behavior for thermionic emission, they have been combined with transition metals d. Thermionic emission was studied with cermets in compact samples. Following systems were examined: TiC-Nb, TiC-Mo, TiC-W, ZrC-Nb, ZrC-Mo, ZrC-W, WC-Mo with compositions of: 75% M 1 C-25% M 2 , 50%M 1 C-50%M 2 , 25%M 1 C-75%M 2 . When following the variation of electron emission energy phi versus the composition, it appears that in the range of mixed crystals (M 1 M 2 )C, phi decreases and the resistance to thermal variations of these phases is higher than that of individual carbides. The study of obtained cermets shows that their resistance to thermal variations is largely superior to the one of starting carbides; TiC and ZrC carbides, combined with molybdenum and tungsten support the highest number of thermic cycles

Gridded thermionic gun and integral superconducting ballistic bunch compression cavity

Energy Technology Data Exchange (ETDEWEB)

Schultheiss, Thomas [Advanced Energy Systems, Inc., Medford, NY (United States)

2015-11-16

Electron-Ion colliders such as the Medium energy Electron Ion Collider (MEIC) being developed by JLAB require high current electrons with low energy spread for electron cooling of the collider ring. Accelerator techniques for improving bunch charge, average current, emittance, and energy spread are required for Energy Recovery Linacs (ERLs) and Circulator Rings (CR) for next generation colliders for nuclear physics experiments. Example candidates include thermionic-cathode electron guns with RF accelerating structures. Thermionic cathodes are known to produce high currents and have excellent lifetime. The success of the IR and THz Free-Electron Laser (FEL) designed and installed by Advanced Energy Systems at the Fritz Haber Institute (FHI) of the Max Planck Society in Berlin [1,2] demonstrates that gridded thermionic cathodes and rf systems be considered for next generation collider technology. In Phase 1 Advanced Energy Systems (AES) developed and analyzed a design concept using a superconducting cavity pair and gridded thermionic cathode. Analysis included Beam Dynamics and thermal analysis to show that a design of this type is feasible. The latest design goals for the MEIC electron cooler were for electron bunches of 420 pC at a frequency of 952.6 MHz with a magnetic field on the cathode of 2kG. This field magnetizes the beam imparting angular momentum that provides for helical motion of the electrons in the cooling solenoid. The helical motion increases the interaction time and improves the cooling efficiency. A coil positioned around the cathode providing 2kG field was developed. Beam dynamics simulations were run to develop the particle dynamics near the cathode and grid. Lloyd Young added capability to Tstep to include space charge effects between two plates and include image charge effects from the grid. He also added new pepper-pot geometry capability to account for honeycomb grids. These additions were used to develop the beam dynamics for this gun. The

NASA-OAST photovoltaic energy conversion program

Science.gov (United States)

Mullin, J. P.; Loria, J. C.

1984-01-01

The NASA program in photovoltaic energy conversion research is discussed. Solar cells, solar arrays, gallium arsenides, space station and spacecraft power supplies, and state of the art devices are discussed.

NASA-OAST program in photovoltaic energy conversion

Science.gov (United States)

Mullin, J. P.; Flood, D. J.

1982-01-01

The NASA program in photovoltaic energy conversion includes research and technology development efforts on solar cells, blankets, and arrays. The overall objectives are to increase conversion efficiency, reduce mass, reduce cost, and increase operating life. The potential growth of space power requirements in the future presents a major challenge to the current state of technology in space photovoltaic systems.

Energy Conversion & Storage Program, 1993 annual report

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1994-06-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: production of new synthetic fuels; development of high-performance rechargeable batteries and fuel cells; development of high-efficiency thermochemical processes for energy conversion; characterization of complex chemical processes and chemical species; and the study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

Review and summary of Solar Thermal Conversion Program planning assistance

Energy Technology Data Exchange (ETDEWEB)

1975-06-01

The Solar Thermal Conversion Program comprises a major part of the national solar energy program which must be continuously reviewed and modified where necessary. Modifications are typically required to reflect technical achievements and uncertainties which arise from within the program or from other technical programs, changes in budgets available for supporting the program as well as internal program funding priorities, changing goals such as through acceleration or stretch-out of the program schedule, significant organizational changes involving responsible governmental agencies, the introduction of new project management support contractors, and required budget or schedule changes occurring within individual projects that make up the Solar Thermal Conversion Program. The Aerospace Corporation has provided data to assist in planning, review, coordination, and documentation of the overall Solar Thermal Conversion Program. The Solar Thermal Conversion Program Plan is described in detail. Sections 2.0 through 5.0 cover the discussion and detail planning covering the objectives, justification, basic and alternative plans, budgets, and schedules for the Solar Thermal sub-unit portion of the Solar Electric Applications effort. Appendices B1, B2, and B3 include the March 21, March 28, and April 5, 1975, Program Plan submissions of the complete Solar Electric Applications effort. In Appendix B the Solar Thermal, Solar Photovoltaic, Wind Energy, and Ocean Thermal sub-unit texts have been condensed and formatted for integration in the overall ERDA budget package. (WHK)

X-Band Thermionic Cathode RF Gun at UTNL

CERN Document Server

Fukasawa, Atsushi; Dobashi, Katsuhiro; Ebina, Futaro; Hayano, Hitoshi; Higo, Toshiyasu; Kaneyasu, Tatsuo; Matsuo, Kennichi; Ogino, Haruyuki; Sakae, Hisaharu; Sakamoto, Fumito; Uesaka, Mitsuru; Urakawa, Junji

2005-01-01

The X-band (11.424 GHz) linac for compact Compton scattering hard X-ray source are under construction at Nuclear Engineering Research Laboratory, University of Tokyo. This linac designed to accelerate up to 35 MeV, and this electron beam will be used to produce hard X-ray by colliding with laser. It consists of a thermionic cathode RF gun, an alpha magnet, and a traveling wave tube. The gun has 3.5 cells (unloaded Q is 8250) and will be operated at pi-mode. A dispenser cathode is introduced. Since the energy spread of the beam from the gun is predicted to be broad due to the continuous emission from the thermionic cathode, a slit is placed in the alpha magnet to eliminate low energy electrons. The simulation on the injector shows the beam energy 2.9 MeV, the charge 23 pC/bunch, and the emittance less than 10 mm.mrad. The experiment on the gun is planed in the beginning of 2005, and the details will be discussed on the spot.

Thermionic cogeneration burner assessment study. Third quarterly technical progress report, April-June, 1983

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

The specific tasks of this study are to mathematically model the thermionic cogeneration burner, experimentally confirm the projected energy flows in a thermal mock-up, make a cost estimate of the burner, including manufacturing, installation and maintenance, review industries in general and determine what groups of industries would be able to use the electrical power generated in the process, select one or more industries out of those for an in-depth study, including determination of the performance required for a thermionic cogeneration system to be competitive in that industry. Progress is reported. (WHK)

The 20 year evolution of an energy conversion course at the United States Military Academy

International Nuclear Information System (INIS)

Bailey, Margaret; Oezer Arnas, A.; Potter, Robert; Samples, Jerry W.

2004-01-01

Over the past several years, an energy conversion course offered by the Mechanical Engineering Program at the United States Military Academy in West Point, New York, has evolved into a cohesive series of lessons addressing three general topical areas: advanced thermodynamics, advanced mechanical system analysis, and direct energy conversion systems. Mechanical engineering majors enroll in Energy Conversion Systems (ME 472) during the fall semester of their senior year as an advanced elective. ME 472 builds directly on the material covered in Thermodynamics (EM 301) taken during the student's junior year. In the first segment of ME 472, the students study advanced thermodynamic topics including exergy and combustion analyses. The students then analyze various mechanical systems including refrigeration systems, internal combustion engines, boilers, and fossil fuel fired steam and gas turbine combined power plants. Exergetic efficiencies of various equipment and systems are determined. The final portion of the course covers direct energy conversion technology, including fuel cells, photovoltaics, thermoelectricity, thermionics and magnetohydrodynamics. Supplemental lessons on energy storage, semi-conductors and nonreactive energy sources (such as solar collectors, wind turbines, and hydroelectric plants) are included here. This paper discusses the evolution of ME 472 since its inception and explains the motivations for the course's progress

Energy Conversion and Storage Requirements for Hybrid Electric Aircraft

Science.gov (United States)

Misra, Ajay

2016-01-01

Among various options for reducing greenhouse gases in future large commercial aircraft, hybrid electric option holds significant promise. In the hybrid electric aircraft concept, gas turbine engine is used in combination with an energy storage system to drive the fan that propels the aircraft, with gas turbine engine being used for certain segments of the flight cycle and energy storage system being used for other segments. The paper will provide an overview of various energy conversion and storage options for hybrid electric aircraft. Such options may include fuel cells, batteries, super capacitors, multifunctional structures with energy storage capability, thermoelectric, thermionic or a combination of any of these options. The energy conversion and storage requirements for hybrid electric aircraft will be presented. The role of materials in energy conversion and storage systems for hybrid electric aircraft will be discussed.

Processes of preparation, deposition and analysis of thermionic emissive substances

International Nuclear Information System (INIS)

Romao, B.M. Verdelli; Muraro Junior, A.; Tessaroto, L.A.B.; Takahashi, J.

1992-09-01

This paper shows the results of the optimization of the process of preparation and deposition of thermionic emissive substances that are used in the oxide-cathodes which are utilized in the gun of the IEAv linear electron accelerator. (author). 5 refs., 5 figs

Non-equilibrium thermionic electron emission for metals at high temperatures

Science.gov (United States)

Domenech-Garret, J. L.; Tierno, S. P.; Conde, L.

2015-08-01

Stationary thermionic electron emission currents from heated metals are compared against an analytical expression derived using a non-equilibrium quantum kappa energy distribution for the electrons. The latter depends on the temperature decreasing parameter κ ( T ) , which decreases with increasing temperature and can be estimated from raw experimental data and characterizes the departure of the electron energy spectrum from equilibrium Fermi-Dirac statistics. The calculations accurately predict the measured thermionic emission currents for both high and moderate temperature ranges. The Richardson-Dushman law governs electron emission for large values of kappa or equivalently, moderate metal temperatures. The high energy tail in the electron energy distribution function that develops at higher temperatures or lower kappa values increases the emission currents well over the predictions of the classical expression. This also permits the quantitative estimation of the departure of the metal electrons from the equilibrium Fermi-Dirac statistics.

Thermionic reactor power conditioner design for nuclear electric propulsion.

Science.gov (United States)

Jacobsen, A. S.; Tasca, D. M.

1971-01-01

Consideration of the effects of various thermionic reactor parameters and requirements upon spacecraft power conditioning design. A basic spacecraft is defined using nuclear electric propulsion, requiring approximately 120 kWe. The interrelationships of reactor operating characteristics and power conditioning requirements are discussed and evaluated, and the effects on power conditioner design and performance are presented.

Energy conversion & storage program. 1995 annual report

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1996-06-01

The 1995 annual report discusses laboratory activities in the Energy Conversion and Storage (EC&S) Program. The report is divided into three categories: electrochemistry, chemical applications, and material applications. Research performed in each category during 1995 is described. Specific research topics relate to the development of high-performance rechargeable batteries and fuel cells, the development of high-efficiency thermochemical processes for energy conversion, the characterization of new chemical processes and complex chemical species, and the study and application of novel materials related to energy conversion and transmission. Research projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials and deposition technologies, and advanced methods of analysis.

Thermionic vacuum arc (TVA) technique for magnesium thin film deposition

Energy Technology Data Exchange (ETDEWEB)

Balbag, M.Z., E-mail: zbalbag@ogu.edu.t [Eskisehir Osmangazi University, Education Faculty, Primary Education, Meselik Campus, Eskisehir 26480 (Turkey); Pat, S.; Ozkan, M.; Ekem, N. [Eskisehir Osmangazi University, Art and Science Faculty, Physics Department, Eskisehir 26480 (Turkey); Musa, G. [Ovidius University, Physics Department, Constanta (Romania)

2010-08-15

In this study, magnesium thin films were deposited on glass substrate by the Thermionic Vacuum Arc (TVA) technique for the first time. We present a different technique for deposition of high-quality magnesium thin films. By means of this technique, the production of films is achieved by condensing the plasma of anode material generated using Thermionic Vacuum Arc (TVA) under high vacuum conditions onto the surface to be coated. The crystal orientation and morphology of the deposited films were investigated by using XRD, EDX, SEM and AFM. The aim of this study is to search the use of TVA technique to coat magnesium thin films and to determine some of the physical properties of the films generated. Furthermore, this study will contribute to the scientific studies which search the thin films of magnesium or the compounds containing magnesium. In future, this study will be preliminary work to entirely produce magnesium diboride (MgB{sub 2}) superconductor thin film with the TVA technique.

Review and analysis of the 1980-1989 biomass thermochemical conversion program

Energy Technology Data Exchange (ETDEWEB)

Stevens, D.J.

1994-09-01

In the period between 1980 and 1989, the U.S. Department of Energy (DOE) sponsored research and development projects through its Biomass Thermochemical Conversion (BTC) Program. Thermochemical conversion technologies use elevated temperatures to convert biomass into more useful forms of energy such as fuel gases or transportation fuels. The BTC Program included a wide range of biomass conversion projects in the areas of gasification, pyrolysis, liquefaction, and combustion. This work formed the basis of the present DOE research and development efforts on advanced liquid fuel and power generation systems. At the beginning of Fiscal Year 1989, the management of the BTC Program was transferred from Pacific Northwest Laboratory (PNL) to National Renewable Energy Laboratory (NREL, formerly Solar Energy Research Institute). This document presents a summary of the research which was performed under the BTC Program during the 1981-1989 time frame. The document consists of an analysis of the research projects which were funded by the BTC Program and a bibliography of published documents. This work will help ensure that information from PNL`s BTC Program is available to those interested in biomass conversion technologies. The background of the BTC Program is discussed in the first chapter of this report. In addition, a brief summary of other related biomass research and development programs funded by the U.S. Department of Energy and others is presented with references where additional information can be found. The remaining chapters of the report present a detailed summary of the research projects which were funded by the BTC Program. The progress which was made on each project is summarized, the overall impact on biomass conversion is discussed, and selected references are provided.

Highly-Efficient Thermoelectronic Conversion of Heat and Solar Radiation to Electric Power

OpenAIRE

Meir, Stefan

2013-01-01

Thermionic energy conversion has long been a candidate to convert solar radiation and the combustion heat of fossil fuels into electricity at high efficiencies. However, the formation of electron space charges has prevented the widespread use of the principle since its was first suggested in 1915. In this work, a novel mechanism to suppress the effects of the space charge was investigated: the acceleration of electrons in a special configuration of electric and magnetic fields. This work d...

3-D simulation study for a thermionic RF gun using an FDTD method

Energy Technology Data Exchange (ETDEWEB)

Hama, H. E-mail: hama@lns.tohoku.ac.jp; Hinode, F.; Shinto, K.; Miyamoto, A.; Tanaka, T

2004-08-01

Beam dynamics in a thermionic RF gun for a new pre-injector in a future synchrotron radiation facility at Tohoku university has been studied by developing a 3-D Maxwell's equation solver. Backbombardment (BB) effect on a cathode, which is a crucial problem for performance of the thermionic RF gun, has been investigated. It is found that an external dipole magnetic field applying around the cathode is effective to reduce high-energy backstreaming electrons from the accelerating cell. However, the low-energy electrons coming back from the first cell inevitably hit the cathode, so that characteristics of the cathode material seems to be crucial for reduction of the BB effect.

A thermionic energy converter with a molybdenum-alumina cermet emitter

NARCIS (Netherlands)

Gubbels, G.H.M.; Wolff, L.R.; Metselaar, R.

1990-01-01

A study is made of the properties of cermets as electrode materials for thermionic energy converters. For thermodynamic reasons it is expected that all cermets composed of pure Mo and refractory oxides have the same bare work function. From data on the work function of Mo in an oxygen atmosphere

The direct conversion of heat into electricity in reactors; Conversion directe de la chaleur en electricite dans les piles

Energy Technology Data Exchange (ETDEWEB)

Devin, B; Bliaux, J; Lesueur, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The direct conversion of heat into electricity by thermionic emission in an atomic reactor has been studied with the triple aim of its utilisation: as an energy source for a space device, at the head of a conventional conversion system in power installations, or finally in association with the thermoelectric conversion in very low power installations. The laboratory experiments were mainly orientated towards the electron extraction of metals and compounds and their behaviour at high temperatures. Converters furnishing up to 50 amps at 0. 4 volts with an efficiency close to 10 p. 100 have been constructed in the laboratory; the emitters were heated by electron bombardment and were composed of tungsten covered with an uranium carbide deposit or molybdenum covered with cesium. The main aspects of the coupling between the converter and the reactor have been covered from the point of view of electronics: the influence of the mismatching of the load on the temperature of the emitter and the influence of thermal flux density on the temperature of the emitter and the stability of the converter. Converters using uranium carbide as the electron emitter have been tested in reactors. Tests have been made under dynamic conditions in order to determine the dynamic characteristics. The load matching curves have been constructed and the overall performances of several cells coupled in such a way as to form a reactor rod have been deduced. This information is fundamental to the design of a control system for a thermionic conversion reactor. The problems associated with the reliability of thermionic converters connected in series in the same reactor rod have been examined theoretically. Finally, the absorption isotherms have been drawn at the ambient temperatures for krypton and xenon on activated carbon with the aim of investigating the escape of fission products in a converter. (author) [French] La conversion directe de chaleur en electricite par emission thermionique dans une

The US plutonium materials conversion program in Russia

International Nuclear Information System (INIS)

Zygmunt, S.J.; Mason, C.F.V.; Hahn, W.K.

2000-01-01

Progress has been made in Russia towards the conversion of weapons-grade plutonium (w-Pu) into plutonium oxide (PuO 2 ) suitable for further manufacture into mixed oxide (MOX) fuels. This program was started in 1998 in response to US proliferation concerns and the acknowledged international need to decrease the available weapons-grade Pu. A similar agenda is being followed in the US to address disposition of US surplus weapons-grade Pu. In Russia a conversion process has been selected and a site proposed. This paper discusses the present state of the program in support of this future operating facility that will process up to 5 metric tons of plutonium a year. (authors)

TFE Verification Program: Semiannual report for the period ending March 31, 1987

International Nuclear Information System (INIS)

1987-04-01

The objective of the TFE program is to demonstrate the technological readiness of a thermionic fuel element suitable for use as the basic element in a thermionic reactor with electric power output in the .5 to 5.0 MWe range, with a full-power life of 7 years. This report summarizes the technical results obtained in this program. Information presented here contains evaluated test data, designs, and experimental results

The Sloping Land Conversion Program in China

DEFF Research Database (Denmark)

Liu, Zhen

conversion program. Our results show that SLCP works as a valid external policy intervention on rural livelihood diversification. In addition, the findings demonstrate that there exist heterogeneous effects of SLCP implementation on livelihood diversification across different rural income groups. The lower...

75 FR 8391 - Assisted Living Conversion Program (ALCP) and Emergency Capital Repair Program (ECRP)

Science.gov (United States)

2010-02-24

... Conversion Program (ALCP) provides funding for the physical costs of converting some or all the units of an... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5376-N-10] Assisted Living Conversion... rehabilitate, modernize, or retrofit aging structure, common areas, or individual dwelling units through the...

Control for nuclear thermionic power source

International Nuclear Information System (INIS)

Fletcher, J.C.; Sawyer, C.D.

1978-01-01

A control for a power source is described which includes nuclear fuel interspersed with thermionic converters, including a power regulator that maintains a substantially constant output voltage to a variable load, and a control circuit that drives a neutron flux regulator in accordance with the current supplied to the power regulator and the neutron flux density in the region of the converters. The control circuit generates a control signal which is the difference between the neutron flux density and a linear fucntion of the current, and which drives the neutron regulator in a direction to decrease or increase the neutron flux according to the polarity of the control signal

Development of integrated thermionic circuits for high-temperature applications

International Nuclear Information System (INIS)

McCormick, J.B.; Wilde, D.; Depp, S.; Hamilton, D.J.; Kerwin, W.; Derouin, C.; Roybal, L.; Dooley, R.

1981-01-01

A class of devices known as integrated thermionic circuits (ITC) capable of extended operation in ambient temperatures up to 500 0 C is described. The evolution of the ITC concept is discussed. A set of practical design and performance equations is demonstrated. Recent experimental results are discussed in which both devices and simple circuits have successfully operated in 500 0 C environments for extended periods of time

Design study on an independently-tunable-cells thermionic RF gun

International Nuclear Information System (INIS)

Hama, H.; Tanaka, T.; Hinode, F.; Kawai, M.

2006-01-01

Characteristics of a thermionic RF gun have been studied by a 3-D simulation code developed using an FDTD (Finite Difference Time Domain) method as a Maxwell's equations solver. The gun is consists of two independent power feeding cavities, so that we call it independently-tunable-cells (ITC)'-RF gun. The first cell is the cathode cell and the second one is an accelerating cell. The ITC gun can be operated at various modes of different RF-power ratio and phase between two cavities. Simulation study shows a velocity-bunching like effect may be occurred in the gun, so that the short pulse beam from the thermionic RF gun is a better candidate to produce the coherent THz synchrotron radiation. Expected bunch length with a total charge of ∼20 pC (1% energy width from the top energy) is around 200 fs (fwhm). Even the beam energy extracted from the gun is varied by which the input powers are changed, almost same shape of the longitudinal phase space can be produced by tuning the phase. (author)

A thermionic energy converter with A molybdenum alumina cermet emitter

NARCIS (Netherlands)

Gubbels, G.H.M.; Wolff, L.R.; Metselaar, R.; Yogi Goswami, D.

1988-01-01

The I-V characteristics of a thermionic converter equipped with a Mo-1w/o AI203 emitter and a Mo collector were measured. The conditions were varied over a limited range without, as well as with Cs. Work functions of Mo as well as Mo-1w/o AI203 were determined. Measurements were carried out in a

SYNCOM: A general syntax conversion language and computer program

International Nuclear Information System (INIS)

Bindon, D.C.

1972-09-01

The problems of syntax conversion are discussed and the reasons given for the choice of the Interpretive method. A full description is given of the SYNCON language and computer program together with brief details of some programs written in the language. (author)

Photovoltaic and thermal energy conversion for solar powered satellites

Science.gov (United States)

Von Tiesenhausen, G. F.

1976-01-01

A summary is provided concerning the most important aspects of present investigations related to a use of solar power satellites (SPS) as a future source of terrestrial energy. General SPS characteristics are briefly considered, early work is reviewed, and a description of current investigations is presented. System options presently under study include a photovoltaic array, a thermionic system, and a closed Brayton cycle. Attention is given to system reference options, basic building blocks, questions of system analysis and engineering, photovoltaic conversion, and the utility interface. It is concluded that an SPS may be cost effective compared to terrestrial systems by 1995.

Communication: IR spectroscopy of neutral transition metal clusters through thermionic emission

NARCIS (Netherlands)

Lapoutre, V. J. F.; Haertelt, M.; Meijer, G.; Fielicke, A.; Bakker, J. M.

2013-01-01

The resonant multiple photon excitation of neutral niobium clusters using tunable infrared (IR) radiation leads to thermionic emission. By measuring the mass-resolved ionization yield as a function of IR wavenumber species selective IR spectra are obtained for Nb-n (n = 5-20) over the 200-350 cm(-1)

Energy Conversion and Storage Program. 1990 annual report

Energy Technology Data Exchange (ETDEWEB)

Cairns, E.J.

1992-03-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Surface properties of ceramic/metal composite materials for thermionic converter applications

International Nuclear Information System (INIS)

Davis, P.R.; Bozack, M.J.; Swanson, L.W.

1983-01-01

Ceramic/metal composite electrode materials are of interest for thermionic energy conversion (TEC) applications for several reasons. These materials consist of submicron metal fibers or islands in an oxide matrix and therefore provide a basis for fabricating finely structured electrodes, with projecting or recessed metallic regions for more efficient electron emission or collection. Furthermore, evaporation and surface diffusion of matrix oxides may provide oxygen enhancement of cesium adsorption and work function lowering at both the collecting and emitting electrode surfaces of the TEC. Finally, the high work function oxide matrix or oxide-metal interfaces may provide efficient surface ionization of cesium for space-charge reduction in the device. The authors are investigating two types of ceramic/metal composite materials. One type is a directionally solidified eutectic consisting of a bulk oxide matrix such as UO 2 or stabilized ZrO 2 with parallel metal fibers (W) running through the oxide being exposed at the surface by cutting perpendicular to the fiber direction. The second type of material, called a surface eutectic, consists of a refractory substrate (Mo) with a thin layer of deposited and segregated material (Mo-Cr 2 O 3 -A1 2 O 3 ) on the surface. The final configuration of this layer is an oxide matrix with metallic islands scattered throughout

Beam emittance measurement from CERN thermionic guns

International Nuclear Information System (INIS)

Kester, O.; Rao, R.; Rinolfi, L.

1992-01-01

In the LEP Injector Linacs (LIL) a thermionic gun provides electron beams with different peak intensities at an energy of 80 keV. The beam emittances were estimated from the EGUN programme. Since the gun is of triode type, the main contribution to the emittance comes from the grid. The simulation programme does not model the real geometry by assuming a cylindrical symmetry, while the grid does not have such symmetry. A Gun Test Facility (GTF), allowing emittance measurements, based on the 3-gradients-method was installed. The experimental results are presented. (author) 6 refs.; 6 figs

A PVTC system integrating photon-enhanced thermionic emission and methane reforming for efficient solar power generation

Institute of Scientific and Technical Information of China (English)

Wenjia Li; Hongsheng Wang; Yong Hao

2017-01-01

A new photovoltaic-thermochemical (PVTC) conceptual system integrating photon-enhanced thermionic emission (PETE) and methane steam reforming is proposed.Major novelty of the system lies in its potential adaptivity to primary fuels (e.g.methane) and high efficiencies of photovoltaic and thermochemical power generation,both of which result from its operation at much elevated temperatures (700-1000 ℃)compared with conventional photovoltaic-thermal (PVT) systems.Analysis shows that an overall power generation efficiency of 45.3％ and a net solar-to-electric efficiency of 39.1％ could be reached at an operating temperature of 750 ℃,after considering major losses during solar energy capture and conversion processes.The system is also featured by high solar share (37％) in the total power output,as well as high energy storage capability and very low CO2 emissions,both enabled by the integration of methane reforming with photovoltaic generation at high temperatures.

Small ex-core heat pipe thermionic reactor concept (SEHPTR)

International Nuclear Information System (INIS)

Jacox, M.G.; Bennett, R.G.; Lundberg, L.B.; Miller, B.G.; Drexler, R.L.

1991-01-01

The Idaho National Engineering Laboratory (INEL) has developed an innovative space nuclear power concept with unique features and significant advantages for both Defense and Civilian space missions. The Small Ex-core Heat Pipe Thermionic Reactor (SEHPTR) concept was developed in response to Air Force needs for space nuclear power in the range of 10 to 40 kilowatts. This paper describes the SEHPTR concept and discusses the key technical issues and advantages of such a system

76 FR 52006 - Announcement of Funding Awards for the Assisted Living Conversion Program; Fiscal Year 2009

Science.gov (United States)

2011-08-19

... Year 2009 Assisted Living Conversion Program Arizona Phoenix, Kivel Manor, $3,292,367, 15 units... Awards for the Assisted Living Conversion Program; Fiscal Year 2009 AGENCY: Office of the Assistant... funding under the Notice of Funding Availability (NOFA) for the Assisted Living Conversion Program (ALCP...

Thermionic field emission in gold nitride Schottky nanodiodes

Science.gov (United States)

Spyropoulos-Antonakakis, N.; Sarantopoulou, E.; Kollia, Z.; Samardžija, Z.; Kobe, S.; Cefalas, A. C.

2012-11-01

We report on the thermionic field emission and charge transport properties of gold nitride nanodomains grown by pulsed laser deposition with a molecular fluorine laser at 157 nm. The nanodomains are sandwiched between the metallic tip of a conductive atomic force microscope and a thin gold layer forming thus a metal-semiconductor-metal junction. Although the limited existing data in the literature indicate that gold nitride was synthesized previously with low efficiency, poor stability, and metallic character; in this work, it is shown that gold nitride nanodomains exhibit semiconducting behavior and the metal-semiconductor-metal contact can be modeled with the back-to-back Schottky barrier model. From the experimental I-V curves, the main charge carrier transport process is found to be thermionic field emission via electron tunneling. The rectifying, near symmetric and asymmetric current response of nanocontacts is related to the effective contact area of the gold nitride nanodomains with the metals. A lower limit for the majority charge carriers concentration at the boundaries of nanodomains is also established using the full depletion approximation, as nanodomains with thickness as low as 6 nm were found to be conductive. Current rectification and charge memory effects are also observed in "quite small" conductive nanodomains (6-10 nm) due to stored charges. Indeed, charges near the surface are identified as inversion domains in the phase shift mapping performed with electrostatic force microscopy and are attributed to charge trapping at the boundaries of the nanodomains.

Thermionic Properties of Carbon Based Nanomaterials Produced by Microhollow Cathode PECVD

Science.gov (United States)

Haase, John R.; Wolinksy, Jason J.; Bailey, Paul S.; George, Jeffrey A.; Go, David B.

2015-01-01

Thermionic emission is the process in which materials at sufficiently high temperature spontaneously emit electrons. This process occurs when electrons in a material gain sufficient thermal energy from heating to overcome the material's potential barrier, referred to as the work function. For most bulk materials very high temperatures (greater than 1500 K) are needed to produce appreciable emission. Carbon-based nanomaterials have shown significant promise as emission materials because of their low work functions, nanoscale geometry, and negative electron affinity. One method of producing these materials is through the process known as microhollow cathode PECVD. In a microhollow cathode plasma, high energy electrons oscillate at very high energies through the Pendel effect. These high energy electrons create numerous radical species and the technique has been shown to be an effective method of growing carbon based nanomaterials. In this work, we explore the thermionic emission properties of carbon based nanomaterials produced by microhollow cathode PECVD under a variety of synthesis conditions. Initial studies demonstrate measureable current at low temperatures (approximately 800 K) and work functions (approximately 3.3 eV) for these materials.

THERMIONIC EMISSION ENHANCEMENT FROM CESIUM COATED RHENIUM IN ELECTRIC FIELDS

Energy Technology Data Exchange (ETDEWEB)

de Steese, J. G.; Zollweg, R. J.

1963-04-15

The plasma-anode technique was used to observe anomalously high thermionic emission from a rhenium surface with small cesium coverage, where the work function of the composite surface is greater than the ionization potential of cesium. Data suggest that emission enhancement is caused by increased cesium coverage because of cesiumion trapping near the emitter surface under the influence of an ion-rich sheath. (auth)

Nano-textured W shows improvement of thermionic emission properties

Energy Technology Data Exchange (ETDEWEB)

Barmina, E.V.; Serkov, A.A.; Shafeev, G.A. [General Physics Institute of the Russian Academy of Sciences, Wave Research Center of A.M. Prokhorov, Moscow (Russian Federation); Stratakis, E. [Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, (IESL-FORTH), Heraklion (Greece); University of Crete, Materials Science and Technology Department, Heraklion (Greece); Fotakis, C. [Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, (IESL-FORTH), Heraklion (Greece); University of Crete, Physics Department, Heraklion (Greece); Stolyarov, V.N.; Stolyarov, I.N. [Roentgenprom, Protvino, Moscow (Russian Federation)

2012-01-15

Laser-assisted nano-texturing of W substrates cathodes via ablation in liquid environment is experimentally realized. Two laser sources are used, either a Ti:sapphire femtosecond laser or a Nd:YAG laser with pulse duration of 350 ps. Laser exposure of W results in the formation of hemi-spherical nanostructures situated on top of periodic ripples. Nano-textured thermionic W cathode demonstrates the decrease of the efficient work function by 0.3 eV compared to pristine surface. (orig.)

Athabasca University: Conversion from Traditional Distance Education to Online Courses, Programs and Services

Directory of Open Access Journals (Sweden)

Alan Davis

2001-01-01

Full Text Available In its 30 years of operation, Athabasca University has witnessed the full impact of the growth of online distance education. Its conversion from mixed media course production and telephone/ mail tutoring to a variety of electronic information and communication technologies has been heterogeneous across disciplines and programs. Undergraduate programs in business, computing, and some social science programs have largely led the conversion, and all graduate programs have, since their inception, employed various features of online delivery. The parallel conversion of student services has been equally important to the effectiveness of these processes. The implications of this approach for the quality of offerings, support systems, costing, and the primary mandate of the University (which is to remove barriers, not create them are discussed.

Measuring current emission and work functions of large thermionic cathodes

International Nuclear Information System (INIS)

Fortgang, C.M.

2001-01-01

As one component of the nations Stockpile Stewardship program, Los Alamos National Laboratory is constructing a 20 MeV, 2 kA (with a 4 kA upgrade capability), 3ps induction linac for doing x-ray radiography of explosive devices. The linac is one leg of a facility called the Dual-Axis Radiography Hydrodynamic Test Facility (DARHT). The electron gun is designed to operate at 3.2 MV. The gun is a Pierce type design and uses a 6.5' cathode for 2 kA operation and an 8' cathode for 4 kA operation. We have constructed a small facility called the Cathode Test Stand (CTS) to investigate engineering and physics issues regarding large thermionic dispenser-cathodes. In particular, we have looked at the issues of temperature uniformity on the cathode surface and cathode quality as measured by its work function. We have done thermal imaging of both 8' and 6.5' cathodes. Here we report on measurements of the cathode work function, both the average value and how it vanes across the face of the cathode.

Thermionic system evaluation test (TSET) facility construction: A United States and Russian effort

International Nuclear Information System (INIS)

Wold, S.K.

1993-01-01

The Thermionic System Evaluation Test (TSET) is a ground test of an unfueled Russian TOPAZ-II in-core thermionic space reactor powered by electric heaters. The facility that will be used for testing of the TOPAZ-II systems is located at the New Mexico Engineering Research Institute (NMERI) complex in Albuquerque, NM. The reassembly of the Russian test equipment is the responsibility of International Scientific Products (ISP), a San Jose, CA, company and Inertek, a Russian corporation, with support provided by engineers and technicians from Phillips Laboratory (PL), Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), and the University of New Mexico (UNM). This test is the first test to be performed under the New Mexico Strategic Alliance agreement. This alliance consists of the PL, SNL, LANL, and UNM. The testing is being funded by the Strategic Defense Initiative Organization (SDIO) with the PL responsible for project execution

X-ray Diffraction Studies of the Structure and Thermochemistry of Alkaline-Earth Oxide-Coated Thermionic Cathodes

Science.gov (United States)

Karikari, E. K.; Bassey, E.; Wintucky, Edwin G.

1998-01-01

NASA LeRC has a broad, active cathode technology development program in which both experimental and theoretical studies are being employed to further development of thermionic cathodes for use as electron sources in vacuum devices for communications and other space applications. One important type of thermionic cathode under development is the alkaline-earth oxide-coated (BaO, SrO, CaO) cathode. Significant improvements in the emission characteristics of this cathode have been obtained through modification of the chemical composition and morphology of the oxide coating, with the best result thus far coming from the addition of In2O3 and Sc2O3. Whereas the In2O3 produces a finer, more uniform particle structure, the exact chemical state and role of the Sc2O3 in the emission enhancement is unknown. The purpose of this cooperative agreement is to combine the studies of the surface chemistry and electron emission at NASA LeRC of chemically modified oxide coatings with a study of the thermochemistry and crystal structure using X-ray diffraction equipment and expertise at Clark Atlanta University (CAU). The study at CAU is intended to provide the description and understanding of the structure and thermochemistry needed for further improvement and optimization of the modified coatings. A description of the experimental procedure, preliminary X-ray diffraction test results, together with the design of an ultrahigh vacuum chamber necessary for high temperature thermochemistry studies will be presented.

24 CFR 982.502 - Conversion to voucher program.

Science.gov (United States)

2010-04-01

... Assistance Payment § 982.502 Conversion to voucher program. (a) New HAP contracts. On and after the merger... part, including calculation of the voucher housing assistance payment in accordance with § 982.505... requirements under this part, including calculation of the voucher housing assistance payment in accordance...

A high-brightness thermionic microwave electron gun

Energy Technology Data Exchange (ETDEWEB)

Borland, Michael [Stanford Univ., CA (United States)

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun`s performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ``State-of-the-art`` microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of < 10 π • m_ec • μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10⁹e^- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically < 30 π • m_e • μm.

A high-brightness thermionic microwave electron gun

International Nuclear Information System (INIS)

Borland, M.

1991-02-01

In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ''State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of e c · μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 10 9 e - per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically e · μm

Fermi level splitting and thermionic current improvement in low-dimensional multi-quantum-well (MQW) p-i-n structures

International Nuclear Information System (INIS)

Varonides, Argyrios C.

2006-01-01

Photo-excitation and subsequent thermionic currents are essential components of photo-excited carrier transport in multi-quantum-well photovoltaic (hetero-PV) structures. p-i-n multi-quantum structures are useful probes for a better understanding of PV device properties. Illumination of the intrinsic region of p-i-n multi-structures causes carrier trapping in any of the quantum wells, and subsequent carrier recombination or thermal escape is possible. At the vicinity of a quantum well, we find that the (quasi) Fermi levels undergo an upward split by a small, but non-negligible, energy amount ΔE F in the order of 12 meV. We conclude this fact by comparing the photo-excited carriers trapped in a quantum well, under illumination, to the carrier concentrations under dark. Based on such a prediction, we subsequently relate thermionic current density dependence on Fermi level splitting, concluding that excess thermal currents may increase by a factor of the order of 2. We conclude that illumination causes (a) Fermi level separation and (b) an apparent increase in thermionic currents

Ocean Thermal Energy Conversion (OTEC) program. FY 1977 program summary

Energy Technology Data Exchange (ETDEWEB)

None

1978-01-01

An overview is given of the ongoing research, development, and demonstration efforts. Each of the DOE's Ocean Thermal Energy Conversion projects funded during fiscal year 1977 (October 1, 1976 through September 30, 1977) is described and each project's status as of December 31, 1977 is reflected. These projects are grouped as follows: program support, definition planning, engineering development, engineering test and evaluation, and advanced research and technology. (MHR)

Development of a thermionic magnicon amplifier at 11.4 GHz. Final report for period May 16, 1995 - May 15, 2001

International Nuclear Information System (INIS)

Gold, Steven H.; Fliflet, Arne W.

2001-01-01

This is the final report on the research program ''Development of a Thermionic Magnicon Amplifier at 11.4 GHz,'' which was carried out by the Plasma Physics Division of the Naval Research Laboratory. Its goal was to develop a high-power, frequency-doubling X-band magnicon amplifier, an advanced scanning-beam amplifier, for use in future linear colliders. The final design parameters were 61 MW at 11.424 GHz, 59 dB gain, 59% efficiency, 1 microsecond pulselength and 10 Hz repetition rate. At the conclusion of this program, the magnicon was undergoing high-power conditioning, having already demonstrated high-power operation, phase stability, a linear drive curve, a small operational frequency bandwidth and a spectrally pure, single-mode output

Numerical simulations of the thermionic electron gun for electron-beam welding and micromachining

Czech Academy of Sciences Publication Activity Database

Jánský, Pavel; Zlámal, J.; Lencová, Bohumila; Zobač, Martin; Vlček, Ivan; Radlička, Tomáš

2009-01-01

Roč. 84, č. 2 (2009), s. 357-362 ISSN 0042-207X R&D Projects: GA AV ČR IAA100650805 Institutional research plan: CEZ:AV0Z20650511 Keywords : Numerical simulation * Thermionic emission * Electron gun Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.975, year: 2009

Simple model for the description of a thermionic Cs diode in operation

International Nuclear Information System (INIS)

Tschersich, K.G.

1975-01-01

Because of the small voltage loss in the space between the electrodes, Cs is the most common work medium in thermionic diodes. With the model calculations of the processes in the space between the electrodes, the author aims to explain the formation of Cs ions and the current transport through the electrode gap at these low voltages. (RW/AK) [de

Measures to alleviate the back bombardment effect of thermionic rf electron gun

International Nuclear Information System (INIS)

Huang, Y.; Xie, J.

1991-01-01

Thermionic rf electron gun finds application as a high brightness electron source for rf linacs. However, cathode heating from back-bombardment effect causes a ramp in the macro-pulse beam current and limit the usable pulse width. Three methods: ring cathode, magnetic deflection and laser assisted heating are studied in theory and in experiment. The results of these studies are reported

Theory of thermionic emission from a two-dimensional conductor and its application to a graphene-semiconductor Schottky junction

Science.gov (United States)

Trushin, Maxim

2018-04-01

The standard theory of thermionic emission developed for three-dimensional semiconductors does not apply to two-dimensional materials even for making qualitative predictions because of the vanishing out-of-plane quasiparticle velocity. This study reveals the fundamental origin of the out-of-plane charge carrier motion in a two-dimensional conductor due to the finite quasiparticle lifetime and huge uncertainty of the out-of-plane momentum. The theory is applied to a Schottky junction between graphene and a bulk semiconductor to derive a thermionic constant, which, in contrast to the conventional Richardson constant, is determined by the Schottky barrier height and Fermi level in graphene.

Development of Kabila rocket: A radioisotope heated thermionic plasma rocket engine

Directory of Open Access Journals (Sweden)

Kalomba Mboyi

2015-04-01

Full Text Available A new type of plasma rocket engine, the Kabila rocket, using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is introduced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets. Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions. The self-sufficiency principle is applied by simultaneously heating up the emitting material with the radioisotope decay heat and by powering the different valves of the plasma rocket engine with the same radioisotope decay heat using a radioisotope thermoelectric generator. This rocket engine is then benchmarked against a 1 N hydrazine thruster configuration operated on one of the Pleiades-HR-1 constellation spacecraft. A maximal specific impulse and power saving of respectively 529 s and 32% are achieved with helium as propellant. Its advantages are its power saving capability, high specific impulses and simultaneous ease of storage and restart. It can however be extremely voluminous and potentially hazardous. The Kabila rocket is found to bring great benefits to the existing spacecraft and further research should optimize its geometric characteristics and investigate the physical principals of its operation.

Modeling on a PWR power conversion system with system program

International Nuclear Information System (INIS)

Gao Rui; Yang Yanhua; Lin Meng

2007-01-01

Based on the power conversion system of nuclear and conventional islands of Daya Bay Power Station, this paper models the thermal-hydraulic systems of primary and secondary loops for PWR by using the PWR best-estimate program-RELAP5. To simulate the full-scope power conversion system, not only the traditional basic system models of nuclear island, but also the major system models of conventional island are all considered and modeled. A comparison between the calculated results and the actual data of reactor demonstrates a fine match for Daya Bay Nuclear Power Station, and manifests the feasibility in simulating full-scope power conversion system of PWR by RELAP5 at the same time. (authors)

Nuclear thermionic power plant integration problems

International Nuclear Information System (INIS)

Fraas, A.P.

1967-02-01

The numerous boundary conditions to be met in preparing a well proportioned, properly integrated design for a thermionic cell reactor are discussed with the emphasis on materials and fabrication problems. Pertinent experience with fuel elements, tube header sheets, electric heaters, and pressure vessels is cited to highlight key limitations that have been encountered in structurally similar equipment. A reference design is presented to indicate how one might attempt to satisfy all of the many boundary conditions. The study indicates that it will be difficult to get a reactor core power density greater than about 35 w/cm 3 and that, while it is possible to minimize the ill effects of failures within individual cells by employing series-parallel connections, the study further indicates that there is inherently a high probability of leaks and electrical shorts and arcs within the reactor so that it is doubtful that good reliability can be obtained

The Socioeconomic Assessment of Sloping Land Conversion Program in China

DEFF Research Database (Denmark)

Liu, Zhen

Abstract This thesis mainly focuses on the socioeconomic impact of the largest Ecological Recovery Program ― the Sloping Land Conversion Program (SLCP), also called Grain for Green Program (GFG) in China. The central government initiated this program in 1999 and it was launched nationwide in 2002...... of which support the policy intention of central government according to our own understanding, whereas the effects differ depending on the group, region and period. This research provides a detailed understanding of the treatment effects of the SLCP and thus, contributes to the on-going political debate...

Conversion of research and test reactors to low enriched uranium fuel: technical overview and program status

International Nuclear Information System (INIS)

Roglans-Ribas, J.

2008-01-01

Many of the nuclear research and test reactors worldwide operate with high enriched uranium fuel. In response to worries over the potential use of HEU from research reactors in nuclear weapons, the U.S Department of Energy (DOE) initiated a program - the Reduced Enrichment for Research and Test Reactors (RERTR) - in 1978 to develop the technology necessary to reduce the use of HEU fuel by converting research reactors to low enriched uranium (LEU) fuel. The Reactor Conversion program is currently under the DOE's National Nuclear Security Administration's Global Threat Reduction Initiative (GTRI). 55 of the 129 reactors included in the scope have been already converted to LEU fuel or have shutdown prior to conversion. The major technical activities of the Conversion Program include: (1) the development of advanced LEU fuels; (2) conversion analysis and conversion support; and (3) technology development for the production of Molybdenum-99 (Mo 99 ) with LEU targets. The paper provides an overview of the status of the program, the technical challenges and accomplishments, and the role of international collaborations in the accomplishment of the Conversion Program objectives. Nuclear research and test reactors worldwide have been in operation for over 60 years. Many of these facilities operate with high enriched uranium fuel. In response to increased worries over the potential use of HEU from research reactors in the manufacturing of nuclear weapons, the U.S Department of Energy (DOE) initiated a program - the Reduced Enrichment for Research and Test Reactors (RERTR) - in 1978 to develop the technology necessary to reduce the use of HEU fuel in research reactors by converting them to low enriched uranium (LEU) fuel. The reactor conversion program was initially focused on U.S.-supplied reactors, but in the early 1990s it expanded and began to collaborate with Russian institutes with the objective of converting Russian supplied reactors to the use of LEU fuel.

Prospects for the use of thermionic nuclear power plants for interorbital transfers of space vehicles in near space

International Nuclear Information System (INIS)

Andreev, P.V.; Zhabotinskii, E.E.; Nikonov, A.M.

1993-01-01

In a previous study the authors considered the use of thermionic nuclear power plants with a thermal reactor for interorbital transfers of space vehicles by electrojet propulsion systems (EJPSs), opening up broad prospects for putting payloads into a high orbit with relatively inexpensive means for a launch into a reference orbit, e.g., the Proton launch vehicle. This is of major importance for the commercial use of space technology, in particular, for erecting technological platforms for the production of various materials. In the work reported here the authors continue the study of interorbital transfers and explore the potentialities of thermionic NPPs with a thermal reactor and with a fast reactor. In boosted operation the electrical power of the latter may reach several hundred kilowatts. What type of NPP is desirable for testing an electrojet propulsion system in interorbital transfers from a reference orbit to a high orbit, providing that the time is limited, depends on the class of the launch vehicle characterized by the mass M o that the vehicle can carry into the reference orbit, where radiation safety conditions allow the NPP to be started up. Results of studies are presented that give an idea of the rational choice of type of thermionic NPP for the organization in interorbital transfers

Interactive programs with preschool children bring smiles and conversation to older adults: time-sampling study.

Science.gov (United States)

Morita, Kumiko; Kobayashi, Minako

2013-10-18

Keeping older adults healthy and active is an emerging challenge of an aging society. Despite the importance of personal relationships to their health and well-being, changes in family structure have resulted in a lower frequency of intergenerational interactions. Limited studies have been conducted to compare different interaction style of intergenerational interaction. The present study aimed to compare the changes in visual attention, facial expression, engagement/behaviour, and intergenerational conversation in older adults brought about by a performance-based intergenerational (IG) program and a social-oriented IG program to determine a desirable interaction style for older adults. The subjects of this study were 25 older adults who participated in intergenerational programs with preschool children aged 5 to 6 years at an adult day care centre in Tokyo. We used time sampling to perform a structured observation study. The 25 older participants of intergenerational programs were divided into two groups based on their interaction style: performance-based IG program (children sing songs and dance) and social-oriented IG program (older adults and children play games together). Based on the 5-minute video observation, we compared changes in visual attention, facial expression, engagement/behaviour, and intergenerational conversation between the performance-based and social-oriented IG programs. Constructive behaviour and intergenerational conversation were significantly higher in the social-oriented IG programming group than the performance-based IG programming group (pprogramming group than the performance-based IG programming (pprogramming group than the social-oriented IG programming group (pprograms with preschool children brought smiles and conversation to older adults. The social-oriented IG program allowed older adults to play more roles than the performance-based IG program. The intergenerational programs provide opportunities to fulfil basic human needs and

Thermionic detection of the ionic fragments of continiuum-state pair absorption systems

International Nuclear Information System (INIS)

Hotop, R.; Niemax, K.; Richter, J.; Weber, K.H.

1981-01-01

Using a thermionic diode we have detected the ionic fragments formed by associative ionization and dissociation after continuum-state pair absorption processes in Cs-Cs and Cs-K systems. Assuming an ionization probability of unity of the excited species and calibrating the pair absorption bands by taking into account the known photoionization cross section of the atoms we found excellent agreement with data from classical absorption measurements. (orig.)

Contribution of the anti HIV/AIDS community conversation programs ...

African Journals Online (AJOL)

Background: HIV/AIDS has now been around for about three and half decades since first diagnosed in 1981. If we wish to curb the spread of HIV/AIDS effectively and sustainably, we need to design strategies that help mobilizing communities at large. Anti-HIV/AIDS Community Conversation (CC) Programs are part of ...

Using Multispectral Imaging to Measure Temperature Profiles and Emissivity of Large Thermionic Dispenser, Cathodes

International Nuclear Information System (INIS)

Simmons, D.F.; Fortgang, C.M.; Holtkamp, D.B.

2001-01-01

Thermionic dispenser cathodes are widely used in modern high-power microwave tubes. Use of these cathodes has led to significant improvement in performance. In recent years these cathodes have been used in electron linear accelerators (LINACs), particularly in induction LINACs, such as the Experimental Test Accelerator at Lawrence Livermore National Laboratory and the Relativistic Test Accelerator at Lawrence Berkeley National Laboratory. For induction LINACs, the thermionic dispenser cathode provides greater reproducibility, longer pulse lengths, and lower emittance beams than does a field emission cathode. Los Alamos National Laboratory is fabricating a dual-axis X-ray radiography machine called dual-axis radiograph hydrodynamic test (DARHT). The second axis of DARHT consists of a 2-kA, 20-MeV induction LINAC that uses a 3.2-MeV electron gun with a tungsten thermionic-dispenser cathode. Typically the DARHT cathode current density is 10 A/cm 2 at 1050 C. Under these conditions current density is space-charge limited, which is desirable since current density is independent of temperature. At lower temperature (the temperature-limited regime) there are variations in the local current density due to a nonuniform temperature profile. To obtain the desired uniform current density associated with space-charge limited operation, the coolest area on the cathode must be at a sufficiently high temperature so that the emission is space-charge limited. Consequently, the rest of the cathode is emitting at the same space-charge-limited current density but is at a higher temperature than necessary. Because cathode lifetime is such a strong function of cathode temperature, there is a severe penalty for nonuniformity in the cathode temperature. For example, a temperature increase of 50 C means cathode lifetime will decrease by a factor of at least four. Therefore, we are motivated to measure the temperature profiles of our large-area cathodes

Simulations of thermionic suppression during tungsten transient melting experiments.

Czech Academy of Sciences Publication Activity Database

Komm, Michael; Tolias, P.; Ratynskaia, S.; Dejarnac, Renaud; Gunn, J. P.; Krieger, K.; Podolník, Aleš; Pitts, R.A.; Pánek, Radomír

T170, December (2017), č. článku 014069. ISSN 0031-8949. [PFMC 2017: 16th International Conference on Plasma-Facing Materials and Components for Fusion Applications. Düsseldorf, 16.05.2017-19.05.2017] R&D Projects: GA ČR(CZ) GA16-14228S; GA MŠk(CZ) 8D15001 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : tokamak * thermionic emission * tungsten * melt * plasma-facing component Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 1.3 Physical sciences Impact factor: 1.280, year: 2016 http://iopscience.iop.org/article/10.1088/1402-4896/aa9209

Design and operation of a thermionic converter in air

International Nuclear Information System (INIS)

Horner, M.H.; Begg, L.L.; Smith, J.N. Jr.; Geller, C.B.; Kallnowski, J.E.

1995-01-01

An electrically heated thermionic converter has been designed, built and successfully tested in air. Several unique features were incorporated in this converter: an integral cesium reservoir, innovative ceramic-to-metal seals, a heat rejection system coupling the collector to a low temperature heat sink and an innovative cylindrical heater filament. The converter was operated for extended periods of time with the emitter at about 1900 K. the collector at about 700 K, and a power density of over 2 w(e)/sq. cm. Input power transients were run between 50% and 100% thermal power, at up to 1% per second, without instabilities in performance

Multi-channel pulser for the SLC thermionic electron source

International Nuclear Information System (INIS)

Browne, M.J.; Clendenin, J.E.; Corredoura, P.L.; Jobe, R.K.; Koontz, R.F.; Sodja, J.

1985-01-01

A new pulser developed for the SLC thermionic gun has been operational since September 1984. It consists of two planar triode amplifiers with a common output triode driving the gun cathode to produce two independent pulses of up to 9A with a 3 nsec FWHM pulse width. Three long-pulse amplifiers are also connected to the cathode to produce pulses with widths controllable between 100 nsec and 1.6 μsec. Each amplifier has independent timing and amplitude control through a fiber optic link to the high voltage plane of the gun cathode-grid structure. The pulser and its operating characteristics are described. 15 refs., 3 figs

Synthesis, thermionic emission and magnetic properties of (NdxGd1–x)B6

International Nuclear Information System (INIS)

Bao Li-Hong; Zhang Jiu-Xing; Zhou Shen-Lin; Tegus

2011-01-01

Polycrystalline rare-earth hexaborides (Nd x Gd 1–x )B 6 (x = 0, 0.2, 0.6, 0.8, 1) were prepared by the reactive spark plasma sintering (SPS) method using mixed powder of GdH 2 , NdH 2 and B. The effects of Nd doping on the crystal structure, the grain orientation, the thermionic emission and the magnetic properties of the hexaboride were investigated by X-ray diffraction, electron backscattered diffraction and magnetic measurements. It is found that all the samples sintered by the SPS method exhibit high densities (> 95%) and high values of Vickers hardness (2319 kg/mm 2 ). The values are much higher than those obtained in the traditional method. With the increase of Nd content, the thermionic emission current density increases from 11 to 16.30 A/cm 2 and the magnetic phase transition temperature increases from 5.85 to 7.95 K. Thus, the SPS technique is a suitable method to synthesize the dense rare-earth hexaborides with excellent properties. (interdisciplinary physics and related areas of science and technology)

Reducing Energy Degradation Due to Back-bombardment Effect with Modulated RF Input in S-band Thermionic RF Gun

Science.gov (United States)

Kii, Toshiteru; Nakai, Yoko; Fukui, Toshio; Zen, Heishun; Kusukame, Kohichi; Okawachi, Norihito; Nakano, Masatsugu; Masuda, Kai; Ohgaki, Hideaki; Yoshikawa, Kiyoshi; Yamazaki, Tetsuo

2007-01-01

Energy degradation due to back-bombardment effect is quite serious to produce high-brightness electron beam with long macro-pulse with thermionic rf gun. To avoid the back-bombardment problem, a laser photo cathode is used at many FEL facilities, but usually it costs high and not easy to operate. Thus we have studied long pulse operation of the rf gun with thermionic cathode, which is inexpensive and easy to operate compared to the photocathode rf gun. In this work, to reduce the energy degradation, we controlled input rf power amplitude by controlling pulse forming network of the power modulator for klystron. We have successfully increased the pulse duration up to 4 μs by increasing the rf power from 7.8 MW to 8.5 MW during the macro pulse.

The effect of samarium doping on structure and enhanced thermionic emission properties of lanthanum hexaboride fabricated by spark plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shenlin; Hu, Qianglin [College of Mathematics and Physics, Jinggangshan University, Jian (China); Zhang, Jiuxing; Liu, Danmin [Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing (China); Huang, Qingzhen [NIST Center for Neutron Research, National Institute of Standards and Technology, MD (United States)

2014-03-15

Single-phase polycrystalline solid solutions (La{sub 1-x}Sm{sub x})B{sub 6} (x = 0, 0.2, 0.4, 0.8, 1) are fabricated by spark plasma sintering (SPS). This study demonstrates a systematic investigation of structure-property relationships in Sm-doped LaB{sub 6} ternary rare-earth hexaborides. The microstructure, crystallographic orientation, electrical resistivity, and thermionic emission performance of these compounds are investigated. Analysis of the results indicates that samarium (Sm) doping has a noticeable effect on the structure and performance of lanthanum hexaboride (LaB{sub 6}). The analytical investigation of the electron backscatter diffraction confirms that (La{sub 0.6}Sm{sub 0.4})B{sub 6} exhibits a clear (001) texture that results in a low work function. Work functions are determined by pulsed thermionic diode measurements at 1500-1873 K. The (La{sub 0.6}Sm{sub 0.4})B{sub 6} possesses improved thermionic emission properties compared to LaB{sub 6}. The current density of (La{sub 0.6}Sm{sub 0.4})B{sub 6} is 42.4 A cm{sup -2} at 1873 K, which is 17.5% larger than that of LaB{sub 6}. The values of Φ{sub R} for (La{sub 0.6}Sm{sub 0.4})B{sub 6} and LaB{sub 6} are 1.98 ± 0.03 and 1.67 ± 0.03 eV, respectively. Furthermore, the Sm substitution of lanthanum (La) effectively increases the electrical resistivity. These results reveal that Sm doping lead to significantly enhanced thermionic emission properties of LaB{sub 6}. The compound (La{sub 0.6}Sm{sub 0.4})B{sub 6} appears most promising as a future emitter material. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Design, construction and measurements of an alpha magnet as a solution for compact bunch compressor for the electron beam from Thermionic RF Gun

Science.gov (United States)

Rajabi, A.; Jazini, J.; Fathi, M.; Sharifian, M.; Shokri, B.

2018-03-01

The beam produced by a thermionic RF gun has wide energy spread that makes it unsuitable for direct usage in photon sources. Here in the present work, we optimize the extracted beam from a thermionic RF gun by a compact economical bunch compressor. A compact magnetic bunch compressor (Alpha magnet) is designed and constructed. A comparison between simulation results and experimental measurements shows acceptable conformity. The beam dynamics simulation results show a reduction of the energy spread as well as a compression of length less than 1 ps with 2.3 mm-mrad emittance.

Injection of holes at indium tin oxide/dendrimer interface: An explanation with new theory of thermionic emission at metal/organic interfaces

International Nuclear Information System (INIS)

Peng Yingquan; Lu Feiping

2006-01-01

The traditional theory of thermionic emission at metal/inorganic crystalline semiconductor interfaces is no longer applicable for the interface between a metal and an organic semiconductor. Under the assumption of thermalization of hot carriers in the organic semiconductor near the interface, a theory for thermionic emission of charge carriers at metal/organic semiconductor interfaces is developed. This theory is used to explain the experimental result from Samuel group [J.P.J. Markham, D.W. Samuel, S.-C. Lo, P.L. Burn, M. Weiter, H. Baessler, J. Appl. Phys. 95 (2004) 438] for the injection of holes from indium tin oxide into the dendrimer based on fac-tris(2-phenylpyridyl) iridium(III)

Enhanced Thermionic Emission and Low 1/f Noise in Exfoliated Graphene/GaN Schottky Barrier Diode.

Science.gov (United States)

Kumar, Ashutosh; Kashid, Ranjit; Ghosh, Arindam; Kumar, Vikram; Singh, Rajendra

2016-03-01

Temperature-dependent electrical transport characteristics of exfoliated graphene/GaN Schottky diodes are investigated and compared with conventional Ni/GaN Schottky diodes. The ideality factor of graphene/GaN and Ni/GaN diodes are measured to be 1.33 and 1.51, respectively, which is suggestive of comparatively higher thermionic emission current in graphene/GaN diode. The barrier height values for graphene/GaN diode obtained using thermionic emission model and Richardson plots are found to be 0.60 and 0.72 eV, respectively, which are higher than predicted barrier height ∼0.40 eV as per the Schottky-Mott model. The higher barrier height is attributed to hole doping of graphene due to graphene-Au interaction which shifts the Fermi level in graphene by ∼0.3 eV. The magnitude of flicker noise of graphene/GaN Schottky diode increases up to 175 K followed by its decrease at higher temperatures. This indicates that diffusion currents and barrier inhomogeneities dominate the electronic transport at lower and higher temperatures, respectively. The exfoliated graphene/GaN diode is found to have lower level of barrier inhomogeneities than conventional Ni/GaN diode, as well as earlier reported graphene/GaN diode fabricated using chemical vapor deposited graphene. The lesser barrier inhomogeneities in graphene/GaN diode results in lower flicker noise by 2 orders of magnitude as compared to Ni/GaN diode. Enhanced thermionic emission current, lower level of inhomogeneities, and reduced flicker noise suggests that graphene-GaN Schottky diodes may have the underlying trend for replacing metal-GaN Schottky diodes.

THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun

Energy Technology Data Exchange (ETDEWEB)

Smirnov, Alexei V.; Agustsson, R.; Boucher, S.; Campese, Tara; Chen, Y.C.; Hartzell, Josiah J.; Jocobson, B.T.; Murokh, A.; O' Shea, F.H.; Spranza, E.; Berg, W.; Borland, M.; Dooling, J. C.; Erwin, L.; Lindberg, R. R.; Pasky, S.J.; Sereno, N.; Sun, Y.; Zholents, A.

2017-06-01

Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes including conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.

Impact of the use of low or medium enriched uranium on the masses of space nuclear reactor power systems

International Nuclear Information System (INIS)

1994-12-01

The design process for determining the mass increase for the substitution of low-enriched uranium (LEU) for high-enriched uranium (HEU) in space nuclear reactor systems is an optimization process which must simultaneously consider several variables. This process becomes more complex whenever the reactor core operates on an in-core thermionic power conversion, in which the fissioning of the nuclear fuel is used to directly heat thermionic emitters, with the subsequent elimination of external power conversion equipment. The increased complexity of the optimization process for this type of system is reflected in the work reported herein, where considerably more information has been developed for the moderated in-core thermionic reactors

Analysis of thermionic DC electron gun for 125 MeV linac

International Nuclear Information System (INIS)

Kanno, K.; Sato, Isamu; Sato, K.

2000-01-01

The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

Analysis of thermionic DC electron gun for 125 MeV linac

Energy Technology Data Exchange (ETDEWEB)

Kanno, K. [Graduate School of Science and Technology, Nihon Univ., Funabashi, Chiba (Japan); Sato, Isamu; Sato, K. [Nihon Univ., Funabashi, Chiba (Japan). Atomic Energy Research Inst] [and others

2000-07-01

The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

Particle Simulations of a Thermionic RF Gun with Gridded Triode Structure for Reduction of Back-Bombardment

CERN Document Server

Kusukame, K; Kii, T; Masuda, K; Nakai, Y; Ohgaki, H; Yamazaki, T; Yoshikawa, K; Zen, H

2005-01-01

Thermionic RF guns show advantageous features compared with photocathode ones such as easy operation and much higher repetition rate of micropulses, both of which are suitable for their application to high average power FELs. They however suffer from the back-bombardment effect [1], i.e., in conventional RF guns, electrons are extracted from cathode also in the latter half of accelerating phase and tend to back-stream to hit the cathode, and as a result the macropulse duration is limited down to severalμsec Against this adverse effect in thermionic RF guns, introduction of the triode structure has been proposed [2], where the accelerating phase and amplitude nearby the cathode can be controlled regardless of the phase of the first accelerating cell in the conventional RF gun. Our one-dimensional particle simulation results predict that the back-bombardment power can be reduced by 99 % only with 30-40 kW RF power fed to the grid in the present triode structure with an optimal phase difference from th...

Performance review of thermionic electron gun developed for RF linear accelerators at RRCAT

International Nuclear Information System (INIS)

Wanmode, Yashwant; Mulchandani, J.; Reddy, T.S.; Bhisikar, A.; Singh, H.G.; Shrivastava, Purushottam

2015-01-01

RRCAT is engaged in development of RF electron linear accelerator for irradiation of industrial and agricultural products. Thermionic electron gun is primary source for this accelerator as beam current in the RF accelerator is modest and thermionic emission is most prevalent option for electron gun development. An electron gun has to meet high cathode emission capability, low filament power, good accessibility for cathode replacement and should provide short time for maintenance. Electron linear accelerator up to beam energy of 10 MeV require electron source of 45-50 keV beam energy and emission current of 1 A. Electron optics of gun and electron beam profile simulations were carried out using CST's particle tracking code and EGUN code. Triode type electron gun of cathode voltage 50 kV pulsed has been designed, developed and integrated with 10 MeV electron linear accelerators at RRCAT. Beam current of more than 600 mA has been measured with faraday cup in the test stand developed for characterizing the electron gun. Two accelerators one is imported and another one developed indigenously has been energized using this electron gun. Beam energy of 5-10 MeV has been achieved with beam current of 250-400 mA by integrating this electron gun with the linear accelerator. This paper reviews the performance of indigenously developed electron gun for both linear accelerators. (author)

Computer code conversion using HISTORIAN

International Nuclear Information System (INIS)

Matsumoto, Kiyoshi; Kumakura, Toshimasa.

1990-09-01

When a computer program written for a computer A is converted for a computer B, in general, the A version source program is rewritten for B version. However, in this way of program conversion, the following inconvenient problems arise. 1) The original statements to be rewritten for B version are lost. 2) If the original statements of the A version rewritten for B version would remain as comment lines, the B version source program becomes quite large. 3) When update directives of the program are mailed from the organization which developed the program or when some modifications are needed for the program, it is difficult to point out the part to be updated or modified in the B version source program. To solve these problems, the conversion method using the general-purpose software management aid system, HISTORIAN, has been introduced. This conversion method makes a large computer code a easy-to-use program for use to update, modify or improve after the conversion. This report describes the planning and procedures of the conversion method and the MELPROG-PWR/MOD1 code conversion from the CRAY version to the JAERI FACOM version as an example. This report would provide useful information for those who develop or introduce large programs. (author)

Design and implementation of a fs-resolved transmission electron microscope based on thermionic gun technology

Energy Technology Data Exchange (ETDEWEB)

Piazza, L., E-mail: luca.piazza@epfl.ch [Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), ICMP, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Masiel, D.J. [Integrated Dynamic Electron Solutions, Inc., 455 Bolero Drive, Danville, CA 94526 (United States); LaGrange, T.; Reed, B.W. [Condensed Matter and Materials Division Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Barwick, B. [Department of Physics, Trinity College, 300 Summit St., Hartford, CT 06106 (United States); Carbone, Fabrizio [Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), ICMP, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

2013-09-23

Highlights: • We present the implementation of a femtosecond-resolved ultrafast TEM. • This is the first ultrafast TEM based on a thermionic gun geometry. • An additional condenser lens has been used to maximize the electron count. • We achieved a time resolution of about 300 fs and an energy resolution of 1 eV. - Abstract: In this paper, the design and implementation of a femtosecond-resolved ultrafast transmission electron microscope is presented, based on a thermionic gun geometry. Utilizing an additional magnetic lens between the electron acceleration and the nominal condenser lens system, a larger percentage of the electrons created at the cathode are delivered to the specimen without degrading temporal, spatial and energy resolution significantly, while at the same time maintaining the femtosecond temporal resolution. Using the photon-induced near field electron microscopy effect (PINEM) on silver nanowires the cross-correlation between the light and electron pulses was measured, showing the impact of the gun settings and initiating laser pulse duration on the electron bunch properties. Tuneable electron pulses between 300 fs and several ps can be obtained, and an overall energy resolution around 1 eV was achieved.

Technical challenges in support of the plutonium materials conversion program in Russia

International Nuclear Information System (INIS)

Mason, C.F.V.; Zygmunt, S.J.; Hahn, W.K.; James, C.A.; Costa, D.A.; Smith, W.H.; Yarbro, S.L.

2000-01-01

The Department of Energy's Plutonium Materials Conversion Program for Russia is designed to assist Russia in defining a path for the destruction of weapons grade plutonium. A similar program is currently defining a program for destruction of US weapons grade plutonium. These two sister programs arose from the September 1998 meeting between President Yeltsin and President Clinton, after which they issued a 'Joint statement of principles for management and disposition of plutonium designated as no longer required for defense purposes'. The US and Russia have each committed to convert 50 metric tons of plutonium from nuclear weapons programs to forms which are unusable for weapons

Status of LEU conversion program at CRNL

International Nuclear Information System (INIS)

Kennedy, I.C.

1991-01-01

After briefly reviewing the salient features of the NRU Reactor at Chalk River Nuclear Laboratories (CRNL), the progress of our LEU fuel development and testing program is described. The results (to date) of full-size prototype fuel-rod irradiations are reviewed, and the status of the new fuel-fabrication facility on the site is updated. Although development work is proceeding on U 3 Si 2 dispersions, all indications so far are that CRNL's U 3 Si fuel is fully acceptable for reactor operation. Fuel rods from the new fabrication shop will be installed in NRU in 1990, and the complete core conversion of NRU to LEU driver fuel is expected by 1991. (orig.)

Program description for the program Fuel program conversion 2011-07-01 - 2015-06-30; Programbeskrivning foer programmet Braensleprogrammet omvandling 2011-07-01 - 2015-06-30

Energy Technology Data Exchange (ETDEWEB)

2011-04-15

The Fuel program conversion is included as one of three programs in a cohesive commitment to increased, sustainable and efficient production and use of indigenous and renewable fuels that are implemented by the Swedish Energy Agency during the period July 1, 2011 - June 30, 2015. The program focuses on increasing knowledge and development of technologies for processing of the fuel feedstock, and conversion to primarily heat and electricity in plants up to about 10 MW. Issues of particular concern is to strengthen competitiveness, efficiency and sustainability in the chain from raw material to end use, and increasing raw material base by developing knowledge and technologies for new materials that are current. The program includes basic and applied research, development and demonstration. Within the sub-area Processing efforts are prioritized which streamline and reduce costs in different types of processing operations. Processing here means not just technology for pelleting and briquetting, but also sub-processes that prepare, dry, handle or process raw materials in other ways. Within the sub-area Conversion to heat and electricity in the range <10 MW, the focus is principally, on one hand increasing the knowledge of the interaction between fuel and combustion plant, and on the other hand to implement results of research in collaboration with users and equipment suppliers. Furthermore, great importance is given to increasing the competitiveness of local heating in the transition from oil to renewable heat supply and the use of new fuel materials and fuels. Questions about the fuel supply from forestry and agriculture, including issues of sustainability, environment and resource use are treated in the two parallel running programs, the Fuel program supply and the Fuel program sustainability

Direct energy conversion - state of the art in 1981

International Nuclear Information System (INIS)

Euler, K.J.

1981-01-01

Contemporary research and development of direct energy conversion (D.E.C.) started about 25 years ago. Having considered possibilities, cost, and advantages, the efforts have become more and more steady during the last decade. It has been recognized that, in most cases, D.E.C. methods will serve only as electricity sources for special application. This is true for radioisotopic generators used in space and submarine technologies, for thermoelectric devices used in air defence and along desert pipelines, and for thermionic convertors used in television satellites. Thus, the goal, to introduce these D.E.C. units in large scale manufacture has not been reached, and will not be reached even in the future. Only magneto-hydrodynamic channels exhibit a certain innovation potential as topping devices in advanced thermal power stations. Fuel cells will not be treated here, solar cells only mentioned briefly. (orig.) [de

The effects of China's Sloping Land Conversion Program on agricultural households

DEFF Research Database (Denmark)

Liu, Zhen; Henningsen, Arne

2016-01-01

In the late 1990s, China aimed to mitigate environmental degradation from agricultural production activities by introducing the world's largest "Payments for Environmental Services" program: the Sloping Land Conversion Program (SLCP). We develop a microeconomic Agricultural Household Model, which...... nonfarm labor supply and total consumption in some regions, these effects could not be observed in others. The recent reduction of the SLCP compensation payment rates generally had negligible effects on agricultural production and off-farm work and only very small effects on household consumption....

Environmental monitoring program design for uranium refining and conversion operations

International Nuclear Information System (INIS)

1984-08-01

The objective of this study was to develop recommendations for the design of environmental monitoring programs at Canadian uranium refining and conversion operations. In order to develop monitoring priorities, chemical and radioactive releases to the air and water were developed for reference uranium refining and conversion facilities. The relative significance of the radioactive releases was evaluated through a pathways analysis which estimated dose to individual members of the critical receptor group. The effects of chemical releases to the environment were assessed by comparing predicted air and water contaminant levels to appropriate standards or guidelines. For the reference facilities studied, the analysis suggested that environmental effects are likely to be dominated by airborne release of both radioactive and nonradioactive contaminants. Uranium was found to be the most important radioactive species released to the air and can serve as an overall indicator of radiological impacts for any of the plants considered. The most important nonradioactive air emission was found to be fluoride (as hydrogen fluoride) from the uranium hexafluoride plant. For the uranium trioxide and uranium dioxide plants, air emissions of oxides of nitrogen were considered to be most important. The study recommendations for the design of an environmental monitoring program are based on consideration of those factors most likely to affect local air and water quality, and human radiation exposure. Site- and facility-specific factors will affect monitoring program design and the selection of components such as sampling media, locations and frequency, and analytical methods

Design study of a low-emittance high-repetition rate thermionic rf gun

Directory of Open Access Journals (Sweden)

A. Opanasenko

2017-05-01

Full Text Available We propose a novel gridless continuous-wave radiofrequency (rf thermionic gun capable of generating nC ns electron bunches with a rms normalized slice emittance close to the thermal level of 0.3 mm mrad. In order to gate the electron emission, an externally heated thermionic cathode is installed into a stripline-loop conductor. Two high-voltage pulses propagating towards each other in the stripline-loop overlap in the cathode region and create a quasielectrostatic field gating the electron emission. The repetition rate of pulses is variable and can reach up to one MHz with modern solid-state pulsers. The stripline attached to a rf gun cavity wall has with the wall a common aperture that allows the electrons to be injected into the rf cavity for further acceleration. Thanks to this innovative gridless design, simulations suggest that the bunch emittance is approximately at the thermal level after the bunch injection into the cavity provided that the geometry of the cathode and aperture are properly designed. Specifically, a concave cathode is adopted to imprint an Ƨ-shaped distribution onto the beam transverse phase-space to compensate for an S-shaped beam distribution created by the spherical aberration of the aperture-cavity region. In order to compensate for the energy spread caused by rf fields of the rf gun cavity, a 3rd harmonic cavity is used. A detailed study of the electrodynamics of the stripline and rf gun cavity as well as the beam optics and bunch dynamics are presented.

The design of a 3 GHz thermionic RF-gun and energy filter for MAX-lab

CERN Document Server

Anderberg, B; Demirkan, M; Eriksson, M; Malmgren, L; Werin, S

2002-01-01

A new pre-injector has been designed for the MAX-laboratory. It consists of an RF-gun and a magnetic energy filter. The newly designed RF-gun geometry will be operated at 3 GHz in the thermionic mode using a BaO cathode. The pre-injector will provide a 2.3 MeV electron beam in 3 ps micro pulses to a new injector system currently under construction.

Low work-function thermionic emission and orbital-motion-limited ion collection at bare-tether cathodic contact

Energy Technology Data Exchange (ETDEWEB)

Chen, Xin, E-mail: xin.chen@upm.es; Sanmartín, J. R., E-mail: juanr.sanmartin@upm.es [Departamento de Física Aplicada, Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros, 3, 28040 Madrid (Spain)

2015-05-15

With a thin coating of low-work-function material, thermionic emission in the cathodic segment of bare tethers might be much greater than orbital-motion-limited (OML) ion collection current. The space charge of the emitted electrons decreases the electric field that accelerates them outwards, and could even reverse it for high enough emission, producing a potential hollow. In this work, at the conditions of high bias and relatively low emission that make the potential monotonic, an asymptotic analysis is carried out, extending the OML ion-collection analysis to investigate the probe response due to electrons emitted by the negatively biased cylindrical probe. At given emission, the space charge effect from emitted electrons increases with decreasing magnitude of negative probe bias. Although emitted electrons present negligible space charge far away from the probe, their effect cannot be neglected in the global analysis for the sheath structure and two thin layers in between sheath and the quasineutral region. The space-charge-limited condition is located. It is found that thermionic emission increases the range of probe radius for OML validity and is greatly more effective than ion collection for cathodic contact of tethers.

Low-temperature thermionics in space nuclear power systems with the safe-type fast reactor

International Nuclear Information System (INIS)

Zrodnikov, A.V.; Yarygin, V.I.; Lazarenko, G.E.; Zabudko, A.N.; Ovcharenko, M.K.; Pyshko, A.P.; Mironov, V.S.; Kuznetsov, R.V.

2007-01-01

The potentialities of the use of the low-temperature thermionic converters (TIC) with the emitter temperature ≤ 1500 K in the space nuclear power system (SNPS) with the SAFE-type (Safe Affordable Fission Engine) fast reactor proposed and developed by common efforts of American experts have been considered. The main directions of the 'SAFE-300-TEG' SNPS (300 kW(thermal)) design update by replacing the thermoelectric converters with the low-temperature high-performance thermionic converters (with the barrier index V B ≤ 1.9 eV and efficiency ≥ 10%) meant for a long-term operation (5 years at least) as the components of the SAFE-300-TIC SNPS for a Lunar base have been discussed. The concept of the SNPS with the SAFE-type fast reactor and low-temperature TICs with specific electric power of about 1.45 W/cm 2 as the components of the SAFE-300-TIC system meeting the Nasa's initial requirements to a Lunar base with the electric power demand of about 30 kW(electrical) for robotic mission has been considered. The results, involving optimization and mass-and-size estimation, show that the SAFE-300-TIC system meets the initial requirements by Nasa to the lunar base power supply. The main directions of the system update aimed at the output electric power increase up to 100 kW(electrical) have also been presented. (authors)

Analysis of instability growth and collisionless relaxation in thermionic converters using 1-D PIC simulations

International Nuclear Information System (INIS)

Kreh, B.B.

1994-12-01

This work investigates the role that the beam-plasma instability may play in a thermionic converter. The traditional assumption of collisionally dominated relaxation is questioned, and the beam-plasma instability is proposed as a possible dominant relaxation mechanism. Theory is developed to describe the beam-plasma instability in the cold-plasma approximation, and the theory is tested with two common Particle-in-Cell (PIC) simulation codes. The theory is first confirmed using an unbounded plasma PIC simulation employing periodic boundary conditions, ES1. The theoretically predicted growth rates are on the order of the plasma frequencies, and ES1 simulations verify these predictions within the order of 1%. For typical conditions encountered in thermionic converters, the resulting growth period is on the order of 7 x 10 -11 seconds. The bounded plasma simulation PDP1 was used to evaluate the influence of finite geometry and the electrode boundaries. For this bounded plasma, a two-stream interaction was supported and resulting in nearly complete thermalization in approximately 5 x 10 -10 seconds. Since the electron-electron collision rate of 10 9 Hz and the electron atom collision rate of 10 7 Hz are significantly slower than the rate of development of these instabilities, the instabilities appear to be an important relaxation mechanism

Conceptual engineering design study of thermionic topping of fossil power plants

Energy Technology Data Exchange (ETDEWEB)

1978-02-15

Primary objectives of this study are to investigate alternative design concepts of thermal coupling of thermionic energy converters (TECs) to the steam cycle and the mechanical and electrical aspects of integrating TEC design into the steam power station. The specific tasks include: (1) evaluate design concepts of TEC topping of solvent refined liquified coal-fired steam power plants, with main emphasis devoted to thermal, mechanical, and electrical design aspects. (2) Develop preliminary conceptual design of a modular TEC assembly. (3) Develop preliminary cost estimates of the design modification to a liquified coal-fired steam power plant with TEC topping. (4) Provide support to Thermo Electron Corporation in planning TEC hardware testing. Results are presented in detail.

Energy balance measurements for the determination of physical and technical operation parameters of thermionic converters

International Nuclear Information System (INIS)

Ritz, K.

1975-01-01

An introduction into the fundamental theoretical principles of the thermionic Cs converter is followed by the set-up of a special measuring converter as proposed by J. Bohdansky which permits the defined setting of the electrode distance under service conditions. Measurements thus carried out present quantitative data on efficiency, on energy transfer between the electrodes by means of radiation and heat transfer, and on the actual collector potential, the latter which surprisingly shows a distance dependency. (orig./GG) [de

Responses and mechanisms of positive electron affinity molecules in the N2 mode of the thermionic ionization detector and the electron-capture detector

International Nuclear Information System (INIS)

Jones, C.S.

1989-01-01

Very little knowledge has been acquired in the past on the mechanistic pathway by which molecules respond in the N 2 mode of the thermionic ionization detector. An attempt is made here to elucidate the response mechanism of the detector. The basic response mechanisms are known for the electron capture detector, and an attempt is made to identify the certain mechanism by which selected molecules respond. The resonance electron capture rate constant has been believed to be temperature independent, and investigations of the temperature dependence of electron capture responses are presented. Mechanisms for the N 2 mode of the thermionic ionization detector have been proposed by examining the detector response to positive electron affinity molecules and by measurement of the ions produced by the detector. Electron capture mechanisms for selected molecules have been proposed by examining their temperature dependent responses in the electron capture detector and negative ion mass spectra of the samples. In studies of the resonance electron capture rate constant, the relative responses of selected positive electron affinity molecules and their temperature dependent responses were investigated. Positive electron affinity did not guarantee large responses in the N 2 mode thermionic ionization detector. High mass ions were measured following ionization of samples in the detector. Responses in the electron capture detector varied with temperature and electron affinity

SOLID STATE ENERGY CONVERSION ALLIANCE (SECA) SOLID OXIDE FUEL CELL PROGRAM

Energy Technology Data Exchange (ETDEWEB)

Unknown

2003-06-01

This report summarizes the progress made during the September 2001-March 2002 reporting period under Cooperative Agreement DE-FC26-01NT41245 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid State Energy Conversion Alliance (SECA) Solid Oxide Fuel Cell Program''. The program focuses on the development of a low-cost, high-performance 3-to-10-kW solid oxide fuel cell (SOFC) system suitable for a broad spectrum of power-generation applications. The overall objective of the program is to demonstrate a modular SOFC system that can be configured to create highly efficient, cost-competitive, and environmentally benign power plants tailored to specific markets. When fully developed, the system will meet the efficiency, performance, life, and cost goals for future commercial power plants.

The LEU target development and conversion program for the MAPLE reactors and new processing facility

International Nuclear Information System (INIS)

Malkoske, G.R.

2002-01-01

Historically, the production of molybdenum-99 in the NRU research reactors at Chalk River, Canada has been extracted from reactor targets employing highly enriched uranium (HEU). A reliable supply of HEU metal from the United States used in the manufacture of targets for the NRU research reactor has been a key factor to enable MDS Nordion to develop a secure supply of medical isotopes for the international nuclear medicine community. The molybdenum extraction process from HEU targets provides predictable, consistent yields for our high-volume molybdenum production process. Each link of the isotope supply chain, from isotope production to ultimate use by the physician, has been established using this proven and established method of HEU target irradiation and processing to extract molybdenum-99. To ensure a continued reliable and timely supply of medical isotopes, MDS Nordion is completing the construction of two MAPLE reactors and a New Processing Facility. The design of the MAPLE facilities was based on an established process developed by Atomic Energy of Canada Ltd. (AECL) - extraction of isotopes from HEU target material. However, in concert with the global trend to utilize low enriched uranium (LEU) in research reactors, MDS Nordion has launched a three phase LEU Target Development and Conversion Program for the MAPLE facilities. Phase 1, the Initial Feasibility Study, which identified the technical issues to convert the MAPLE reactor targets from HEU to LEU for large scale commercial production was reported on at the RERTR- 2000 conference. The second phase of the LEU Target Development and Conversion Program was developed with extensive consultation and involvement of experts knowledgeable in target development, process system design, enriched uranium conversion chemistry and commercial scale reactor operations and molybdenum production. This paper will provide an overview of the Phase 2 Conversion Development Program, report on progress to date, and further

Development and fabrication of insulator seals for thermionic diodes

Science.gov (United States)

Poirier, V. L.

1972-01-01

Eight different types of cermet seals for thermionic diodes were investigated: (1) 1 micron Al2O3 with Nb spheres; (2) 200 A Al2O3 with Nb spheres; (3) 1 micron Al2O3 with Nb 1% Zr spheres; (4) 200 A Al2O3 with Nb 1% Zr spheres; (5) Pure Y2O3 with Nb 1% Zr spheres; (6) Y2O3 3% ZrO2 with Nb 1% Zr spheres; (7) Y2O3 10% ZrO2 with Nb 1% Zr spheres; and (8) ZrO2 12% Y2O3 with Nb 1% Zr spheres. Investigations were made to determine the most favorable fabrication techniques and the effect of the bonding cycle, (length of bonding time and shutdown sequences). The analysis of the seals included tensile test, vacuum test, electrical test and metallurgical examination. At the conclusion of the development phase, 36 seals were fabricated for delivery for evaluation.

City of Rio de Janeiro's Gas Distribution Network Conversion Program; Projeto de conversao do Sistema de Distribuicao de Gas Canalizado do Rio de Janeiro

Energy Technology Data Exchange (ETDEWEB)

Costa Filho, Manoel A.F.; Pallottino, Joao T. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Margalef, Jose M. [Companhia Distribuidora de Gas do Rio de Janeiro (CEG), Rio de Janeiro, RJ (Brazil)

2004-07-01

This paper discusses the Conversion Program of Rio de Janeiro city, from Town Gas to Natural Gas, looking for evaluating its logistic and benefits, highlighting mainly those related to consumer's safety. The Conversion Program is been implemented under Companhia Distribuidora de Gas do Rio de Janeiro (CEG) supervision, with support of Rio de Janeiro State University (UERJ) in service's quality appraisal and conversion technical procedure elaboration and review. This partnership has started in 2001 and 46% of all residential and commercial customers have already been converted up to July 2004. Conversion Program is divided into the following Phases: Design and Planning, Gas Distribution Network Renovation and Adaptation, Revision, Post-Revision, Conversion and Post-Conversion. This Program may serve as model for similar programs, to be developed in other cities where Natural Gas will be distributed, displacing the Liquefied Petroleum Gas (LPG), and it is one contribution to achieve the federal governmental goal of 12%-NG-participation within Brazilian Energetic Matrix in 2010. (author)

Communication: Effects of thermionic-gun parameters on operating modes in ultrafast electron microscopy

Directory of Open Access Journals (Sweden)

Erik Kieft

2015-09-01

Full Text Available Ultrafast electron microscopes with thermionic guns and LaB6 sources can be operated in both the nanosecond, single-shot and femtosecond, single-electron modes. This has been demonstrated with conventional Wehnelt electrodes and absent any applied bias. Here, by conducting simulations using the General Particle Tracer code, we define the electron-gun parameter space within which various modes may be optimized. The properties of interest include electron collection efficiency, temporal and energy spreads, and effects of laser-pulse duration incident on the LaB6 source. We find that collection efficiencies can reach 100% for all modes, despite there being no bias applied to the electrode.

Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element

International Nuclear Information System (INIS)

Wernsman, Bernard

1997-01-01

A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40 kW e space nuclear power system that is similar to the 6 kW e TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V's do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution

Summary of space nuclear reactor power systems, 1983--1992

Energy Technology Data Exchange (ETDEWEB)

Buden, D.

1993-08-11

This report summarizes major developments in the last ten years which have greatly expanded the space nuclear reactor power systems technology base. In the SP-100 program, after a competition between liquid-metal, gas-cooled, thermionic, and heat pipe reactors integrated with various combinations of thermoelectric thermionic, Brayton, Rankine, and Stirling energy conversion systems, three concepts:were selected for further evaluation. In 1985, the high-temperature (1,350 K), lithium-cooled reactor with thermoelectric conversion was selected for full scale development. Since then, significant progress has been achieved including the demonstration of a 7-y-life uranium nitride fuel pin. Progress on the lithium-cooled reactor with thermoelectrics has progressed from a concept, through a generic flight system design, to the design, development, and testing of specific components. Meanwhile, the USSR in 1987--88 orbited a new generation of nuclear power systems beyond the, thermoelectric plants on the RORSAT satellites. The US has continued to advance its own thermionic fuel element development, concentrating on a multicell fuel element configuration. Experimental work has demonstrated a single cell operating time of about 1 1/2-y. Technology advances have also been made in the Stirling engine; an advanced engine that operates at 1,050 K is ready for testing. Additional concepts have been studied and experiments have been performed on a variety of systems to meet changing needs; such as powers of tens-to-hundreds of megawatts and highly survivable systems of tens-of-kilowatts power.

Summary of space nuclear reactor power systems, 1983--1992

International Nuclear Information System (INIS)

Buden, D.

1993-01-01

This report summarizes major developments in the last ten years which have greatly expanded the space nuclear reactor power systems technology base. In the SP-100 program, after a competition between liquid-metal, gas-cooled, thermionic, and heat pipe reactors integrated with various combinations of thermoelectric thermionic, Brayton, Rankine, and Stirling energy conversion systems, three concepts:were selected for further evaluation. In 1985, the high-temperature (1,350 K), lithium-cooled reactor with thermoelectric conversion was selected for full scale development. Since then, significant progress has been achieved including the demonstration of a 7-y-life uranium nitride fuel pin. Progress on the lithium-cooled reactor with thermoelectrics has progressed from a concept, through a generic flight system design, to the design, development, and testing of specific components. Meanwhile, the USSR in 1987--88 orbited a new generation of nuclear power systems beyond the, thermoelectric plants on the RORSAT satellites. The US has continued to advance its own thermionic fuel element development, concentrating on a multicell fuel element configuration. Experimental work has demonstrated a single cell operating time of about 1 1/2-y. Technology advances have also been made in the Stirling engine; an advanced engine that operates at 1,050 K is ready for testing. Additional concepts have been studied and experiments have been performed on a variety of systems to meet changing needs; such as powers of tens-to-hundreds of megawatts and highly survivable systems of tens-of-kilowatts power

Comparison between arc drops in ignited thermionic converters with and without ion reflections at the emitter

International Nuclear Information System (INIS)

Lundgren, L.

1985-01-01

The output performance of two thermionic energy converters is compared. One converter has a normal emitter, working with zero field at the emitter which is close to the optimum working point, and the other has a low work function emitter and ion reflection at the emitter. A simple model of the plasma and the sheaths shows that a converter working with a low work function emitter and ion reflections gives a worse performance than a similar converter with a normal emitter

High performance emitter for thermionic diode obtained by chemical vapor deposition

International Nuclear Information System (INIS)

Faron, R.; Bargues, M.; Durand, J.P.; Gillardeau, J.

1973-01-01

Vapor deposition process conditions presently known for tungsten and molybdenum (specifically the range of high temperatures and low pressures) permit the achievement of high performance thermionic emitters when used with an appropriate technology. One example of this uses the following series of successive vapor deposits, the five last vapor deposits constituting the fabrication of the emitting layer: Mo deposit for the formation of the nuclear fuel mechanical support; Mo deposit, which constitutes the sheath of the nuclear fuel; epitaxed Mo--W alloy deposit; epitaxed tungsten deposit; fine-grained tungsten deposit; and tungsten deposit with surface orientation according to plane (110)W. In accordance with vapor deposition techniques previously developed, such a sequence of deposits can easily be achieved with the same equipment, even without having to take out the part during the course of the process. (U.S.)

Thermionic RF Gun and Linac Pre-Injector for SPEAR3

Energy Technology Data Exchange (ETDEWEB)

Park, S.

2003-08-11

Preparations are underway to upgrade the Spear2 to the third generation light source. Installation of all the subsystems will start in April 2003. Although the Spear3 RF system is entirely different from the present form, the pre-injector gun/linac and booster synchrotron will remain the same even after the upgrade. The thermionic rf gun reliability and stability are to be improved to inject 500 mA of stored current in shortest possible time. When a top-up mode is enforced, where the stored beam decay is replenished to maintain the constant current and thus constant light intensity, the Spear3 will take injection every few minutes. In that case the gun, linac, and booster must stay on at all times. In this report we will describe some improvements made on the gun and linac in the recent past, as well as their present performance and future upgrade to be made.

Generation of multi-branch beam with thermionic gun for the Japan linear collider

International Nuclear Information System (INIS)

Naito, T.; Akemoto, M.; Matsumonto, H.; Urakawa, J.; Yoshioka, M.; Akiyama, H.

1992-01-01

We report on the development of a thermionic gun that is capable of producing multi-bunch beam to be used at the KEK Accelerator Test Facility for the Japan Linear Collider project. Two types of grid pulse generators have been developed. One is an avalanche pulse generator. A Y-646E cathode was successfully operated to generate double-bunch beam with a pulse width shorter than 700 ps, bunch spacing 1.4 ns, and a peak current 4.3 A. The other grid pulse generator is a fast ECL circuit with an RF power amplifier. Generation of 20-pulse trains with 2.1 ns time spacing has been demonstrated. (Author) 4 refs., 6 figs

Government Research and Development Summaries: Nuclear, Te, Ti Project Briefs. Monthly report

International Nuclear Information System (INIS)

1988-01-01

Nuclear, Te, Ti Project Briefs describe the status of all RandD programs submitted to the Power Information Center by the government sponsors in energy conversion from fission, fusion, and radioisotope power sources and other thermal systems that use thermionic systems. These briefs also follow related investigations of plasma dynamics. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes

Observation of Repetition-Rate Dependent Emission From an Un-Gated Thermionic Cathode Rf Gun

Energy Technology Data Exchange (ETDEWEB)

Edelen, J. P.; Sun, Y.; Harris, J.R.; Lewellen, J.W.

2017-06-02

Recent work at Fermilab in collaboration with the Advanced Photon Source and members of other national labs, designed an experiment to study the relationship between the RF repetition rate and the average current per RF pulse. While existing models anticipate a direct relationship between these two parameters we observed an inverse relationship. We believe this is a result of damage to the barium coating on the cathode surface caused by a change in back-bombardment power that is unaccounted for in the existing theories. These observations shed new light on the challenges and fundamental limitations associated with scaling an ungated thermionic cathode RF gun to high average current.

BAESNUM, a conversational computer program for the Bayesian estimation of a parameter by a numerical method

International Nuclear Information System (INIS)

Colombo, A.G.; Jaarsma, R.J.

1982-01-01

This report describes a conversational computer program which, via Bayes' theorem, numerically combines the prior distribution of a parameter with a likelihood function. Any type of prior and likelihood function can be considered. The present version of the program includes six types of prior and employs the binomial likelihood. As input the program requires the law and parameters of the prior distribution and the sample data. As output it gives the posterior distribution as a histogram. The use of the program for estimating the constant failure rate of an item is briefly described

Contributions to the study of positive ion kinetics in gases

International Nuclear Information System (INIS)

Popescu, A.

1978-01-01

Extensive studies on cesium ion kinetics in cesium and cesium-noble gas mixtures were performed. The obtained data are correlated with the measured parameters of the thermionic diodes. The mobility of atomic and molecular cesium ions at low electric fields, including zero electric field, in cesium and cesium krypton mixtures were measured using the time of flight method and a special thermionic ion detector. The atomic ion conversion into molecular ions is theoretically considered in the diffusion equation of the charged particles and the obtained analytical relation is in good agreement with the experimental cesium measured data. The reaction rate of the ion conversion in cesium is considered from these measurements. Measurements on the diffused plasma through the anode (provided with holes) of the cesium thermionic diode supply data on the anode sheath, the ratio of electronic and ionic current, electron temperature and the nature of the cesium ions (atomic or molecular) for various modes of the low voltage arc discharge. The obtained data have been used for the optimization of the thermionic diode parameters, as well as for the development of a new type of device for the detection of impurities in the air. (author)

The influences of noble gas on the volt-ampere characteristics of a thermionic Cs diode

International Nuclear Information System (INIS)

Tschersich, K.G.

1975-10-01

The influence of the distance between electrodes and of the partial pressure of added xenon on the voltage drop in the electrode gap is investigated by measuring current density-voltage curves on plane parallel thermionic test diodes. With unchanged diode parameters, an addition of xenon reduces the voltage drop when the product of Cs vapour pressure and electrode gap is smaller than an optimum value of about 5 x 10 -2 cm.Torr. The xenon influences the mobility and thus the duration of the Cs ions. These procedures are explained and discussed using a relatively simple mathematical model. (GG/LH) [de

Solid State Energy Conversion Alliance (SECA) Solid Oxide Fuel Cell Program

Energy Technology Data Exchange (ETDEWEB)

Nguyen Minh

2006-07-31

This report summarizes the work performed for Phase I (October 2001 - August 2006) under Cooperative Agreement DE-FC26-01NT41245 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled 'Solid State Energy Conversion Alliance (SECA) Solid Oxide Fuel Cell Program'. The program focuses on the development of a low-cost, high-performance 3-to-10-kW solid oxide fuel cell (SOFC) system suitable for a broad spectrum of power-generation applications. During Phase I of the program significant progress has been made in the area of SOFC technology. A high-efficiency low-cost system was designed and supporting technology developed such as fuel processing, controls, thermal management, and power electronics. Phase I culminated in the successful demonstration of a prototype system that achieved a peak efficiency of 41%, a high-volume cost of $724/kW, a peak power of 5.4 kW, and a degradation rate of 1.8% per 500 hours. . An improved prototype system was designed, assembled, and delivered to DOE/NETL at the end of the program. This prototype achieved an extraordinary peak efficiency of 49.6%.

Sexy gene conversions: locating gene conversions on the X-chromosome.

Science.gov (United States)

Lawson, Mark J; Zhang, Liqing

2009-08-01

Gene conversion can have a profound impact on both the short- and long-term evolution of genes and genomes. Here, we examined the gene families that are located on the X-chromosomes of human (Homo sapiens), chimpanzee (Pan troglodytes), mouse (Mus musculus) and rat (Rattus norvegicus) for evidence of gene conversion. We identified seven gene families (WD repeat protein family, Ferritin Heavy Chain family, RAS-related Protein RAB-40 family, Diphosphoinositol polyphosphate phosphohydrolase family, Transcription Elongation Factor A family, LDOC1-related family, Zinc Finger Protein ZIC, and GLI family) that show evidence of gene conversion. Through phylogenetic analyses and synteny evidence, we show that gene conversion has played an important role in the evolution of these gene families and that gene conversion has occurred independently in both primates and rodents. Comparing the results with those of two gene conversion prediction programs (GENECONV and Partimatrix), we found that both GENECONV and Partimatrix have very high false negative rates (i.e. failed to predict gene conversions), which leads to many undetected gene conversions. The combination of phylogenetic analyses with physical synteny evidence exhibits high resolution in the detection of gene conversions.

Sheath insulator final test report, TFE Verification Program

Energy Technology Data Exchange (ETDEWEB)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications.

Sheath insulator final test report, TFE Verification Program

International Nuclear Information System (INIS)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications

Standard guide for establishing a quality assurance program for uranium conversion facilities

CERN Document Server

American Society for Testing and Materials. Philadelphia

2004-01-01

1.1 This guide provides guidance and recommended practices for establishing a comprehensive quality assurance program for uranium conversion facilities. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1.3 The basic elements of a quality assurance program appear in the following order: FUNCTION SECTION Organization 5 Quality Assurance Program 6 Design Control 7 Instructions, Procedures & Drawings 8 Document Control 9 Procurement 10 Identification and Traceability 11 Processes 12 Inspection 13 Control of Measuring and Test Equipment 14 Handling, Storage and Shipping 15 Inspection, Test and Operating Status 16 Control of Nonconforming Items 17 Corrective Actions 18 Quality Assurance Records 19 Audits 20 TABLE 1 NQA-1 Basic Requirements Relat...

Conversion program in Sweden

Energy Technology Data Exchange (ETDEWEB)

Jonsson, E.B. [Studsvik Nuclear AB, Nykoeping (Sweden)

1997-08-01

The conversion of the Swedish 50 MW R2 reactor from HEU to LEU fuel has been successfully accomplished over a 16 cycles long process. The conversion started in January 1991 with the introduction of 6 LEU assemblies in the 8*8 core. The first all LEU core was loaded in March 1993 and physics measurements were performed for the final licensing reports. A total of 142 LEU fuel assemblies have been irradiated up until September 1994 without any fuel incident. The operating licence for the R2 reactor was renewed in mid 1994 taking into account new fuel type. The Swedish Nuclear Inspectorate (SKI) pointed out one crucial problem with the LEU operation, that the back end of the LEU fuel cycle has not yet been solved. For the HEU fuel Sweden had the reprocessing alternative. The country is now relying heavily on the success of the USDOEs Off Site Fuels Policy to take back the spent fuel from the research reactors. They have in the meantime increased their intermediate storage facilities. There is, however, a limit both in time and space for storage of MTR-type of assemblies in water. The penalty of the lower thermal neutron flux in LEU cores has been reduced by improvements of the new irradiation rigs and by fine tuning the core calculations. The Studsvik code package, CASMO-SIMULATE, widely used for ICFM in LWRs has been modified to suit the compact MTR type of core.

Experimental investigation of high temperature high voltage thermionic diode for the space power nuclear reactor

International Nuclear Information System (INIS)

Onufriyev, Valery V.

2001-01-01

It is well known that the rise of arc from the dense glow discharge is connected with the thermion and secondary processes on the cathode surface (Granovsky, 1971; Leob, 1953; Engel, 1935). First model of breakdown of the cathode layer is connected with the increase of the cathode temperature in consequence of the ion bombardment that leads to the grows its thermo-emissive current. Other model shows the main role of the secondary effects on the cathode surface-the increase of the secondary ion emission coefficient--γ i with the grows of glow discharge voltage. But the author of this investigation work of breakdown in Cs vapor (a transmission the glow discharge into self-maintaining arc discharge) discovered the next peculiarity: the value of breakdown voltage is constant when the values of vapor temperature (its pressure p cs ) and cathode temperature T k is constant too (U b =constant with T k =constant and p cs =constant) and it is not a statistical value (Onufryev, Grishin, 1996) (that was observed in gas glow discharges other authors (Granovsky, 1971; Leob, 1953; Engel, 1935)). The investigations of thermion high voltage high temperature diode (its breakdown characteristics in closed state and voltage-current characteristics in disclosed state) showed that the value of the breakdown voltage is depended on the vapor pressure in inter-electrode gap (IEG)-p cs and cathode temperature-T k and is independent on IEG length--Δ ieg . On this base it was settled that the main role in transition of glow discharge to self-maintaining arc discharge plays an ion cathode layer but more exactly--the region of excited atoms--''Aston glow.''

Experimental investigation of high temperature high voltage thermionic diode for the space power nuclear reactor

Science.gov (United States)

Onufriyev, Valery. V.

2001-02-01

It is well known that the rise of arc from the dense glow discharge is connected with the thermion and secondary processes on the cathode surface (Granovsky, 1971; Leob, 1953; Engel, 1935). First model of breakdown of the cathode layer is connected with the increase of the cathode temperature in consequence of the ion bombardment that leads to the grows its thermo-emissive current. Other model shows the main role of the secondary effects on the cathode surface-the increase of the secondary ion emission coefficient-γi with the grows of glow discharge voltage. But the author of this investigation work of breakdown in Cs vapor (a transmission the glow discharge into self-maintaining arc discharge) discovered the next peculiarity: the value of breakdown voltage is constant when the values of vapor temperature (its pressure pcs) and cathode temperature Tk is constant too (Ub=constant with Tk=constant and pcs=constant) and it is not a statistical value (Onufryev, Grishin, 1996) (that was observed in gas glow discharges other authors (Granovsky, 1971; Leob, 1953; Engel, 1935)). The investigations of thermion high voltage high temperature diode (its breakdown characteristics in closed state and voltage-current characteristics in disclosed state) showed that the value of the breakdown voltage is depended on the vapor pressure in inter-electrode gap (IEG)-pcs and cathode temperature-Tk and is independent on IEG length-Δieg. On this base it was settled that the main role in transition of glow discharge to self-maintaining arc discharge plays an ion cathode layer but more exactly-the region of excited atoms-``Aston glow.'' .

Photon-Enhanced Thermionic Emission in Cesiated p-Type and n-Type Silicon

DEFF Research Database (Denmark)

Reck, Kasper; Dionigi, Fabio; Hansen, Ole

2014-01-01

electrons. Efficiencies above 60% have been predicted theoretically for high solar concentration systems. Silicon is an interesting absorber material for high efficiency PETE solar cells, partly due to its mechanical and thermal properties and partly due to its electrical properties, including a close......Photon-enhanced thermionic emission (PETE) is a relatively new concept for high efficiency solar cells that utilize not only the energy of electrons excited across the band gap by photons, as in conventional photovoltaic solar cells, but also the energy usual lost to thermalization of the excited...... to ideal band gap. The work function of silicon is, however, too high for practical PETE implementations. A well-known method for lowering the work function of silicon (and other materials) is to apply approximately a monolayer of cesium to the silicon surface. We present the first measurements of PETE...

The Conversion of Wiswesser Line Notations to Ring Codes. I. The Conversion of Ring Systems

Science.gov (United States)

Granito, Charles E.; And Others

1972-01-01

The computerized conversion of Wiswesser Line Notations to Ring Codes, using a two-part approach, and the set of computer programs generated for the conversion of ring systems are described. (9 references) (Author)

ForConX: A forcefield conversion tool based on XML.

Science.gov (United States)

Lesch, Volker; Diddens, Diddo; Bernardes, Carlos E S; Golub, Benjamin; Dequidt, Alain; Zeindlhofer, Veronika; Sega, Marcello; Schröder, Christian

2017-04-05

The force field conversion from one MD program to another one is exhausting and error-prone. Although single conversion tools from one MD program to another exist not every combination and both directions of conversion are available for the favorite MD programs Amber, Charmm, Dl-Poly, Gromacs, and Lammps. We present here a general tool for the force field conversion on the basis of an XML document. The force field is converted to and from this XML structure facilitating the implementation of new MD programs for the conversion. Furthermore, the XML structure is human readable and can be manipulated before continuing the conversion. We report, as testcases, the conversions of topologies for acetonitrile, dimethylformamide, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate comprising also Urey-Bradley and Ryckaert-Bellemans potentials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The outlook for application of powerful nuclear thermionic reactor -powered space electric jet propulsion engines

International Nuclear Information System (INIS)

Semyonov, Y.P.; Bakanov, Y.A.; Synyavsky, V.V.; Yuditsky, V.D.

1997-01-01

This paper summarizes main study results for application of powerful space electric jet propulsion unit (EJPUs) which is powered by Nuclear Thermionic Power Unit (NTPU). They are combined in Nuclear Power/Propulsion Unit (NPPU) which serves as means of spacecraft equipment power supply and spacecraft movement. Problems the paper deals with are the following: information satellites delivery and their on-orbit power supply during 10-15 years, removal of especially hazardous nuclear wastes, mining of asteroid resources and others. Evaluations on power/time/mass relationship for this type of mission are given. EJPU parameters are compatible with Russian existent or being under development launch vehicle. (author)

Factors influencing success of metal to plastic conversion programs for under-hood applications

Energy Technology Data Exchange (ETDEWEB)

Male, L.J. [Amoco Chemicals Polymers Business Group, Alpharetta, GA (United States); Desai, K.C.

1995-12-31

This paper compares high performance engineering polymers available today for under-hood applications. It includes an example of an end cap showing value-added capabilities such as design for machining and assembly (DFMA), team approach and computer aided engineering being used for a most cost-effective custom molding solution. These techniques should be part of standard design procedure for conversion programs to cope with the challenges of today and tomorrow. (orig./HW)

ANALYTICAL MODELING OF ELECTRON BACK-BOMBARDMENT INDUCED CURRENT INCREASE IN UN-GATED THERMIONIC CATHODE RF GUNS

Energy Technology Data Exchange (ETDEWEB)

Edelen, J. P. [Fermilab; Sun, Y. [Argonne; Harris, J. R. [AFRL, NM; Lewellen, J. W. [Los Alamos Natl. Lab.

2016-09-28

In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, fieldenhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

TFE design package final report, TFE Verification Program

International Nuclear Information System (INIS)

1994-06-01

The program objective is to demonstrate the technology readiness of a TFE suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW(e) range, and a full-power life of 7 years. A TFE for a megawatt class system is described. Only six cells are considered for simplicity; a megawatt class TFE would have many more cells, the exact number dependent on optimization trade studies

Life Testing and Diagnostics of a Planar Out-of-Core Thermionic Converter

Science.gov (United States)

Thayer, Kevin L.; Ramalingam, Mysore L.; Young, Timothy J.; Lamp, Thomas R.

1994-07-01

This paper details the design and performance of an automated computer data acquisition system for a planar, out-of-core thermionic converter with CVD rhenium electrodes. The output characteristics of this converter have been mapped for emitter temperatures ranging from approximately 1700K to 2000K, and life testing of the converter is presently being performed at the design point of operation. An automated data acquisition system has been constructed to facilitate the collection of current density versus output voltage (J-V) and temperature data from the converter throughout the life test. This system minimizes the amount of human interaction necessary during the lifetest to measure and archive the data and present it in a usable form. The task was accomplished using a Macintosh Ilcx computer, two multiple-purpose interface boards, a digital oscilloscope, a sweep generator, and National Instrument's LabVIEW application software package.

Electric strength of metal-ceramic brazed units of thermionic energy converters in cesium vapours

International Nuclear Information System (INIS)

Belousenko, A.P.; Vasilchenko, A.V.; Nikolaev, Y.V.

1989-01-01

The investigation of electric strength characteristics of the hollow metal-ceramic brazed units of thermionic energy converters with the insulator 1 = 10-50 mm from polycrystal aluminum oxide at the temperature T = 450-750 degrees and the cesium vapour pressure P Cs = 10 - 1 -10 3 Pa has been carried out. The experimental dependencies of the break-down voltage of the brazed units on the temperature, parameter P Cs · 1 and the value of surface electric resistance of the insulators are given as well as the empiric equations obtained with the help of experimental data for calculating the break-down voltage. A mechanism of ceramic insulator influence on electric strength characteristics of the cesium gap is investigated. A breakdown model explaining this influence is proposed

Energy conversion and utilization technologies

International Nuclear Information System (INIS)

1988-01-01

The DOE Energy Conversion and Utilization Technologies (ECUT) Program continues its efforts to expand the generic knowledge base in emerging technological areas that support energy conservation initiatives by both the DOE end-use sector programs and US private industry. ECUT addresses specific problems associated with the efficiency limits and capabilities to use alternative fuels in energy conversion and end-use. Research is aimed at understanding and improving techniques, processes, and materials that push the thermodynamic efficiency of energy conversion and usage beyond the state of the art. Research programs cover the following areas: combustion, thermal sciences, materials, catalysis and biocatalysis, and tribology. Six sections describe the status of direct contact heat exchange; the ECUT biocatalysis project; a computerized tribology information system; ceramic surface modification; simulation of internal combustion engine processes; and materials-by-design. These six sections have been indexed separately for inclusion on the database. (CK)

A Computer Program for Modeling the Conversion of Organic Waste to Energy

Directory of Open Access Journals (Sweden)

Pragasen Pillay

2011-11-01

Full Text Available This paper presents a tool for the analysis of conversion of organic waste into energy. The tool is a program that uses waste characterization parameters and mass flow rates at each stage of the waste treatment process to predict the given products. The specific waste treatment process analysed in this paper is anaerobic digestion. The different waste treatment stages of the anaerobic digestion process are: conditioning of input waste, secondary treatment, drying of sludge, conditioning of digestate, treatment of digestate, storage of liquid and solid effluent, disposal of liquid and solid effluents, purification, utilization and storage of combustible gas. The program uses mass balance equations to compute the amount of CH4, NH3, CO2 and H2S produced from anaerobic digestion of organic waste, and hence the energy available. Case studies are also presented.

Optical techniques for electron-beam characterizations on the APS SASE FEL project

International Nuclear Information System (INIS)

Lumpkin, A.H.; Yang, B.X.; Berg, W.J.; White, M.; Lewellen, J.W.; Milton, S.V.

1998-01-01

At the Advanced Photon Source (APS) the injector linac's DC thermionic gun is being supplemented by a low-emittance rf thermionic gun that will support the SASE FEL project. To address the anticipated smaller beam sizes, the standard Chromox beam-profiling screens are being complemented by optical transition radiation (OTR) and Ce-doped YAG single-crystal converters. Direct comparisons of the effective conversion efficiency, spatial resolution, and time response of the three converter screen types have been performed using the DC thermionic gun's beam accelerated to 400 to 650 MeV. An apparent blurring of observed beam size with increasing incident charge areal density in the YAG crystal was observed for the first time. Only the OTR was prompt enough for the few-ps domain micropulse bunch length measurements performed with a stream camera. Initial beam images of the rf-thermionic gun beam have also been obtained

Current transmission and nonlinear effects in un-gated thermionic cathode RF guns

Energy Technology Data Exchange (ETDEWEB)

Edelen, J. P. [Fermilab; Harris, J. R. [Air Force Weapons Lab

2017-05-03

Un-gated thermionic cathode RF guns are well known as a robust source of electrons for many accelerator applications. These sources are in principle scalable to high currents without degradation of the transverse emittance due to control grids but they are also known for being limited by back-bombardment. While back-bombardment presents a significant limitation, there is still a lack of general understanding on how emission over the whole RF period will affect the nature of the beams produced from these guns. In order to improve our understanding of how these guns can be used in general we develop analytical models that predict the transmission efficiency as a function of the design parameters, study how bunch compression and emission enhancement caused by Schottky barrier lowering affect the output current profile in the gun, and study the onset of space-charge limited effects and the resultant virtual cathode formation leading to a modulation in the output current distribution.

Recommended methods for evaluating the benefits of ECUT Program outputs. [Energy Conversion and Utilization

Energy Technology Data Exchange (ETDEWEB)

Levine, L.O.; Winter, C.

1986-03-01

This study was conducted to define and develop techniques that could be used to assess the complete spectrum of positive effects resulting from the Energy Conversion and Utilization Technologies (ECUT) Program activities. These techniques could then be applied to measure the benefits from past ECUT outputs. In addition, the impact of future ECUT outputs could be assessed as part of an ongoing monitoring process, after sufficient time has elapsed to allow their impacts to develop.

Adherence of diamond films on refractory metal substrates for thermionic applications

International Nuclear Information System (INIS)

Tsao, B.H.; Ramalingam, M.L.; Adams, S.F.; Cloyd, J.S.

1991-01-01

Diamond films are currently being considered as electrical insulation material for application in the thermionic fuel element of a power producing nuclear reactor system. The function of the diamond insulator in this application is to electrically isolate the collector of each cell in the TFE from the coolant and outer sheath. Deposition of diamond films on plane surfaces of Si/SiO 2 have already been demonstrated to be quite effective. However, the diamond films on refractory metal surfaces tend to spall off in the process of deposition revealing an inefficient adherence characteristic between the film and the substrate. This paper is geared towards explaining this deficiency by way of selected experimentation and the use of analytical tools to predict uncertainties such as the mismatch in coefficient of expansion, micrographic study of the interface between the film and the substrate and X-ray diffraction spectra. The investigation of the adherence characteristics of several diamond films on Mo and Nb substrates revealed that there was an allowable stress that resulted in the formation of the critical thickness for the diamond film

Thermionic cooling devices based on resonant-tunneling AlGaAs/GaAs heterostructure

Science.gov (United States)

Bescond, M.; Logoteta, D.; Michelini, F.; Cavassilas, N.; Yan, T.; Yangui, A.; Lannoo, M.; Hirakawa, K.

2018-02-01

We study by means of full quantum simulations the operating principle and performance of a semiconductor heterostructure refrigerator combining resonant tunneling filtering and thermionic emission. Our model takes into account the coupling between the electric and thermal currents by self-consistently solving the transport equations within the non-equilibrium Green’s function framework and the heat equation. We show that the device can achieve relatively high cooling power values, while in the considered implementation, the maximum lattice temperature drop is severely limited by the thermal conductivity of the constituting materials. In such an out-of-equilibrium structure, we then emphasize the significant deviation of the phonon temperature from its electronic counterpart which can vary over several hundred Kelvin. The interplay between those two temperatures and the impact on the electrochemical potential is also discussed. Finally, viable options toward an optimization of the device are proposed.

Determination of rare earth elements in high purity rare earth oxides by liquid chromatography, thermionic mass spectrometry and combined liquid chromatography/thermionic mass spectrometry

International Nuclear Information System (INIS)

Stijfhoorn, D.E.; Stray, H.; Hjelmseth, H.

1993-01-01

A high-performance liquid chromatographic (HPLC) method for the determination of rare earth elements in rocks has been modified and used for the determination of rare earth elements (REE) in high purity rare earth oxides. The detection limit was 1-1.5 ng or 2-3 mg/kg when a solution corresponding to 0.5 mg of the rare earth oxide was injected. The REE determination was also carried out by adding a mixture of selected REE isotopes to the sample and analysing the collected HPLC-fractions by mass spectrometry (MS) using a thermionic source. Since the matrix element was not collected, interference from this element during the mass spectrometric analysis was avoided. Detection limits as low as 0.5 mg/kg could then be obtained. Detection limits as low as 0.05 mg/kg were possible by MS without HPLC-pre-separation, but this approach could only be used for those elements that were not affected by the matrix. Commercial samples of high purity Nd 2 O 3 , Gd 2 O 3 and Dy 2 O 3 were analysed in this study, and a comparison of results obtained by HPLC, combined HPLC/MS and direct MS is presented. (Author)

Political Conversation in Everyday Communicative Contexts

Directory of Open Access Journals (Sweden)

Ângela Cristina Salgueiro Marques

2008-10-01

Full Text Available This article looks at forms of interaction and communicative exchanges in discussion groups composed of beneficiaries of a Brazilian income transfer program (Bolsa-Família Program and at how these forms contribute to the deliberative process. Discussion groups are used as a method for showing how everyday conversation and political discussion are interrelated. Our interest is not to analyze this program, but rather represents an attempt to capture and research moments in which group participants establish their own position relative to one another. At such moments, conversations on everyday subjects and personal dramas shift towards attitudes that include taking the risk of expressing dissonant opinions, explaining background assumptions, and producing counter-narratives. Eight discussion groups were established in two Brazilian cities in the Southeastern region: four in Belo Horizonte (MG and four in Campinas (SP. Keywords: everyday conversation; political discussion; deliberative process; discussion groups; poor women.

Effect of the work function and emission of the collector on the parameters of thermionic converters (TC)

International Nuclear Information System (INIS)

Kaibyshev, V.Z.

1986-01-01

In the optimal, relative to the temperature of the collector, state of modern thermionic converters (TC) the emission of the electrons from it has a substantial effect on the voltage drop in the gap. This paper preents an analysis of the boundary conditions at the collector of the TC. Calculations are presented which show that with a constant current the plasma parameters at the boundary with the collector are virtually independent of the emission from the collector right up to vanishing of the potential jump. The optimal regime with respect to temperatuer and work function of the collector is examined. The collector with a nonuniform work function is discussed

Review of some past and present powder metallurgy programs at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Sheinberg, H.

1977-01-01

Powder metallurgy programs at LASL are reviewed. Topics covered include: KIWI reactor fuel elements; Phoebus reactor fuel elements, criticality control and poison plate material, structural composites for fuel element supports, and heat shields for fuel element supports; thermionic emitter reactor uranium carbide--zirconium carbide fuel pins, and molybdenum--uranium oxide fuel pins; laser and electron beam fusion targets; and current work in MHD components

Composite metal-ceramic material for high temperature energy conversion applications

NARCIS (Netherlands)

Wolff, L.R.

1988-01-01

At Eindhoven Universitu of technology a composite metal-ceramic material is being developed. It will serve as a protective confinement for a combustion heated Thermionic Energy Converter (TEC). This protective confinement of 'hot shell' consists of a composite W-TiN-SiC layer structure. The outer

An update on the LEU target development and conversion program for the MAPLE reactors and new processing facility

International Nuclear Information System (INIS)

Malkoske, G.R.; Eng, B.Sc; Eng, P.

2002-01-01

Historically, the production of molybdenum-99 in the NRU research reactors at Chalk River, Canada, has been extracted from reactor targets employing highly enriched uranium (HEU). A reliable supply of HEU metal from the United States used in the manufacture of targets for the NRU research reactor has been a key factor to enable MDS Nordion to develop a secure supply of medical isotopes for the international nuclear medicine community. The molybdenum extraction process from HEU targets provides predictable, consistent yields for our high-volume molybdenum production process. Each link of the isotope supply chain, from isotope production to ultimate use by the physician, has been established using this proven and established method of HEU target irradiation and processing to extract molybdenum-99. To ensure a continued reliable and timely supply of medical isotopes, MDS Nordion is completing the construction of two MAPLE reactors and a New Processing Facility. The design of the MAPLE facilities was based on an established process developed by Atomic Energy of Canada Ltd. (AECL)-extraction of isotopes from HEU target material. However, in concert with the global trend to utilize low enriched uranium (LEU) in research reactors, MDS Nordion has launched a three phase LEU Target Development and Conversion Program for the MAPLE facilities. Phase 1, the Initial Feasibility Study, which identified the technical issues to convert the MAPLE reactor targets from HEU to LEU for large scale commercial production was reported on at the RERTR-2000 conference. The second phase of the LEU Target Development and Conversion Program was developed with extensive consultation and involvement of experts knowledgeable in target development, process system design, enriched uranium conversion chemistry and commercial scale reactor operations and molybdenum production. This paper will provide an overview of the Phase 2 Conversion Development Program, report on progress to date, and further

Mission operations for unmanned nuclear electric propulsion outer planet exploration with a thermionic reactor spacecraft.

Science.gov (United States)

Spera, R. J.; Prickett, W. Z.; Garate, J. A.; Firth, W. L.

1971-01-01

Mission operations are presented for comet rendezvous and outer planet exploration NEP spacecraft employing in-core thermionic reactors for electric power generation. The selected reference missions are the Comet Halley rendezvous and a Jupiter orbiter at 5.9 planet radii, the orbit of the moon Io. The characteristics of the baseline multi-mission NEP spacecraft are presented and its performance in other outer planet missions, such as Saturn and Uranus orbiters and a Neptune flyby, are discussed. Candidate mission operations are defined from spacecraft assembly to mission completion. Pre-launch operations are identified. Shuttle launch and subsequent injection to earth escape by the Centaur D-1T are discussed, as well as power plant startup and the heliocentric mission phases. The sequence and type of operations are basically identical for all missions investigated.

Some properties of low-vapor-pressure braze alloys for thermionic converters

Science.gov (United States)

Bair, V. L.

1978-01-01

Density, dc electrical resistivity, thermal conductivity, and linear thermal expansion are measured for arc-melted rod-shaped samples of binary eutectics of Zr, Hf, Ru, Nb, Ir, Mo, Ta, Os, Re, and W selected as very-low-pressure braze fillers for thermionic converters. The first two properties are measured at 296 K for Zr-21.7 at% Ru, Zr-13 wt% W, Zr-19 wt% W, Zr-22.3 at% Nb, Nb-66.9 at% Ru, Hf-25.3 wt% Re, Zr-25.7 at% Ta, Hf-22.5 at% W, and Nb-35 wt% Mo. The last property is measured from 293 K to 2/3 melting point for specified alloys of different compositions. Resistivities of 0.000055 to 0.000181 ohm-cm are observed with the alloys having resistivities about ten times that of the less resistive constituent metal and about three times that of the more resistive constituent metal, except for Zr-19 wt% W and Nb-35 wt% Mo (greater resistivities). Thermal expansion coefficients vary from 0.000006 to 0.0000105/K. All brazes exhibit linear thermal expansion near that of their constituent metals.

Impact of defense conversion and US response

International Nuclear Information System (INIS)

Montanarelli, N.

1994-01-01

Conversion from military to civilian products due to defense conversion after the end of the Cold War takes a long as 20 years. In USA there are over 50 government programs funded to assist in defence conversion. This paper concentrates on the three major programs that will have the greatest impact on the economy, in the framework of the issues and needs of American industry. Federal government and US industry are making a considerable effort to transform how to do business today. One of the most important emerging themes in the federal program is international competitiveness. Large federal expenditures are made to support research and development that will increase productivity, thereby helping industry in global economic competition. This, in turn will play a key role in absorbing a large quantity od resources affected by the end of the Cold War

IECEC '92; Proceedings of the 27th Intersociety Energy Conversion Engineering Conference, San Diego, CA, Aug. 3-7, 1992. Vols. 1-6

International Nuclear Information System (INIS)

Anon.

1992-01-01

The present conference discusses spacecraft power requirements, spacecraft nuclear power reactors, power electronics, aerospace fuel cells and batteries, automated spacecraft power systems and power electronics, small excore heat pipe thermionic reactor technology, spacecraft solar power, thermoelectrics for reactors, high voltage systems, spacecraft static/dynamic conversion component technology, wireless power transmission, isotopic-fueled power systems, and aircraft electric power. Also discussed are alkali-metal thermoelectric converters, advanced heat engine cycles, terrestrial electric propulsion, fuel cells for terrestrial applications, MHD systems, magnetic bearings and flywheels, aquifer thermal storage, superconducting devices, nucler fusion power, marine energy systems, Stirling engine cycle analyses and models, Stirling refrigerators and cryocoolers, efficiency and conservation-related practices, Stirling heat pumps, Stirling cycle solar (terrestrial) energy systems, Stirling engine component technologies, environmental impacts of energy systems, Stirling-based power generation, and Stirling heat transport systems

Conversion of SMART I. Zur Konvertierung von SMART I

Energy Technology Data Exchange (ETDEWEB)

Argyris, J H; Szimmat, J; William, K J [Stuttgart Univ. (TH) (Germany, F.R.). Inst. fuer Statik und Dynamik der Luft- und Raumfahrtkonstruktionen

1977-01-01

The report describes the conversion of the programming system SMART I on CDC, UNIVAC and IBM computers under the BMFT grant RK 21 I/SBB 31. There were four tasks for the development of a machine-independent SMART-version: a) Updating of the CDC source library (ca. 180.000 Fortran statements); b) Conversion into double precision; c) Primary installation on UNIVAC; d) Primary installation on IBM. The conversion of the SMART I program was carried out in cooperation with the consulting firms RIB, Stuttgart, and IKOSS Stuttgart, under the leadership of ISD.

2011 Biomass Program Platform Peer Review: Biochemical Conversion

Energy Technology Data Exchange (ETDEWEB)

Pezzullo, Leslie [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

2012-02-01

This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Biochemical Conversion Platform Review meeting.

2011 Biomass Program Platform Peer Review. Thermochemical Conversion

Energy Technology Data Exchange (ETDEWEB)

Grabowski, Paul E. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

2012-02-01

This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Thermochemical Conversion Platform Review meeting.

IECEC '87; Proceedings of the Twenty-second Intersociety Energy Conversion Engineering Conference, Philadelphia, PA, Aug. 10-14, 1987. Volumes 1, 2, 3, and 4

International Nuclear Information System (INIS)

Anon.

1987-01-01

Papers are presented on space power requirements and issues, space photovoltaic systems, space solar dynamic systems, space thermal systems, manned and unmanned space power systems, thermionics, and thermoelectrics. Also considered are high power devices for space power systems, high power conversion for space power systems, 1-10 kWe nuclear space power sources, 100-kW class nuclear power concepts, space reactor safety, and multimegawatt space nuclear power systems. Other topics include space power systems automation, space kilovolt technology, space power electronics, space lithium and nickel-cadmium batteries, lithium sodium storage, and space fuel cells. Papers are also presented on space nickel hydrogen batteries, alternative energy concepts and fuels, fuel cell technology, flow batteries, high-temperature batteries, energy conservation, battery energy storage, thermal energy storage, heat engines, MHD power systems, nuclear fission, and the Stirling cycle

The LEU target development and conversion program for the MAPLE reactors and new processing facility

International Nuclear Information System (INIS)

Malkoske, G.R.

2003-01-01

The availability of isotope grade, Highly Enriched Uranium (HEU), from the United States for use in the manufacture of targets for molybdenum-99 production in AECL's NRU research reactor has been a key factor to enable MDS Nordion to develop a reliable, secure supply of medical isotopes for the international nuclear medicine community. The molybdenum extraction process from HEU targets is a proven and established method that has reliably produced medical isotopes for several decades. The HEU process provides predictable, consistent yields for our high-volume, molybdenum-99 production. Other medical isotopes such as I-131 and Xe-133, which play an important role in nuclear medicine applications, are also produced from irradiated HEU targets as a by-product of the molybdenum-99 process. To ensure a continued reliable and timely supply of medical isotopes, MDS Nordion is completing the commissioning of two MAPLE reactors and an associated isotope processing facility (the New Processing Facility). The new MAPLE facilities, which will be dedicated exclusively to medical isotope production, will provide an essential contribution to a secure, robust global healthcare system. Design and construction of these facilities has been based on a life cycle management philosophy for the isotope production process. This includes target irradiation, isotope extraction and waste management. The MAPLE reactors will operate with Low Enriched Uranium (LEU) fuel, a significant contribution to the objectives of the RERTR program. The design of the isotope production process in the MAPLE facilities is based on an established process - extraction of isotopes from HEU target material. This is a proven technology that has been demonstrated over more than three decades of operation. However, in support of the RERTR program and in compliance with U.S. legislation, MDS Nordion has undertaken a LEU Target Development and Conversion Program for the MAPLE facilities. This paper will provide an

Measurement and modeling of advanced coal conversion processes

Energy Technology Data Exchange (ETDEWEB)

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. (Advanced Fuel Research, Inc., East Hartford, CT (United States) Brigham Young Univ., Provo, UT (United States))

1991-01-01

The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

Research and Development of a New Field Enhanced Low Temperature Thermionic Cathode that Enables Fluorescent Dimming and Loan Shedding without Auxiliary Cathode Heating

Energy Technology Data Exchange (ETDEWEB)

Feng Jin

2009-01-07

This is the final report for project entitled 'Research and development of a new field enhanced low temperature thermionic cathode that enables fluorescent dimming and load shedding without auxiliary cathode heating', under Agreement Number: DE-FC26-04NT-42329. Under this project, a highly efficient CNT based thermionic cathode was demonstrated. This cathode is capable of emitting electron at a current density two order of magnitude stronger then a typical fluorescent cathode at same temperatures, or capable of emitting at same current density but at temperature about 300 C lower than that of a fluorescent cathode. Detailed fabrication techniques were developed including CVD growth of CNTs and sputter deposition of oxide thin films on CNTs. These are mature technologies that have been widely used in industry for large scale materials processing and device fabrications, thus, with further development work, the techniques developed in this project can be scaled-up in manufacturing environment. The prototype cathodes developed in this project were tested in lighting plasma discharge environment. In many cases, they not only lit and sustain the plasma, but also out perform the fluorescent cathodes in key parameters such like cathode fall voltages. More work will be needed to further evaluate more detailed and longer term performance of the prototype cathode in lighting plasma.

SOLID STATE ENERGY CONVERSION ALLIANCE (SECA) SOLID OXIDE FUEL CELL PROGRAM

Energy Technology Data Exchange (ETDEWEB)

Nguyen Minh; Jim Powers

2003-10-01

This report summarizes the work performed for April 2003--September 2003 reporting period under Cooperative Agreement DE-FC26-01NT41245 for the U.S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid State Energy Conversion Alliance (SECA) Solid oxide Fuel Cell Program''. During this reporting period, the conceptual system design activity was completed. The system design, including strategies for startup, normal operation and shutdown, was defined. Sealant and stack materials for the solid oxide fuel cell (SOFC) stack were identified which are capable of meeting the thermal cycling and degradation requirements. A cell module was tested which achieved a stable performance of 0.238 W/cm{sup 2} at 95% fuel utilization. The external fuel processor design was completed and fabrication begun. Several other advances were made on various aspects of the SOFC system, which are detailed in this report.

Performance evaluation and parametric optimum design of a vacuum thermionic solar cell

International Nuclear Information System (INIS)

Liao, Tianjun; Chen, Xiaohang; Chen, Jincan; Lin, Bihong

2016-01-01

A model of the vacuum thermionic solar cell (VTSC) consisting of a solar concentrator, an emitter, and a collector is proposed, in which the various heat losses including the far- and near-field thermal radiation are taken into account. Formula for the overall efficiency of the system is analytically derived. For given values of the ratio of the front surface area of the absorber to that of the emitter and the vacuum gap between the emitter and the collector, the operating temperatures of the emitter and collector are determined by solving the energy balance equations. The maximum efficiency of the VTSC are calculated for given values of the work functions of the emitter and collector materials, and some key parameters such as the net current density of the VTSC, operating temperatures of the emitter and collector, vacuum gap between the emitter and the collector, and area ratio of the absorber to the emitter are optimally determined. Furthermore, the effects of the work functions and the concentration ratio of the solar irradiation on the performance of the VTSC are discussed and several parametric selection criteria are obtained

Programs that support non-proliferation and defense conversion funded by the US Government

International Nuclear Information System (INIS)

Rutkowski, H.L.

1994-08-01

The proliferation of nuclear, chemical, and biological weapons is a serious problem for international security. Consequently the U.S. government has established an array of programs to fund activities that will inhibit this activity. The problem of proliferation and defense conversion, in general, is quite complicated. The most immediate concern is the actual diversion of weapons materials. In the long term; however, weapons of mass destruction must be destroyed in a safe and environmentally sound manner. Ultimately the solution of the proliferation problem lies in the redirection of the intellectual skills of weapons scientists and engineers to peaceful commercial activities. At the present time the economic conditions in the New Independent States create severe pressure on people with critical weapons knowledge to sell their skills to political entities that are dangerous. There are four programs to be discussed in this paper. The first is the open-quotes Nunn-Lugarclose quotes program which is the largest and is administered by the Department of Defense. Between FY92 and FY94 Congress authorized $1.2B for this activity which is aimed at weapons destruction, storage, and safeguards. The second is the International Science and Technology Center in Moscow and the Science Center about to open in Ukraine. These are joint efforts involving the U.S., the European Community, and Japan to fund projects to prevent proliferation and foster commercial technological activity in Russia, Georgia, and Ukraine. The New Independent States - Industrial Partnering Program is a $35M (FY94) program jointly administered by the Department of Energy and the Department of State

Temperature dependence of photon-enhanced thermionic emission from GaAs surface with nonequilibrium Cs overlayers

Energy Technology Data Exchange (ETDEWEB)

Zhuravlev, A.G. [Rzhanov Institute of Semiconductor Physics, Pr. Lavrentieva, 13, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova, 2, 630090 Novosibirsk (Russian Federation); Alperovich, V.L., E-mail: alper@isp.nsc.ru [Rzhanov Institute of Semiconductor Physics, Pr. Lavrentieva, 13, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova, 2, 630090 Novosibirsk (Russian Federation)

2017-02-15

Highlights: • Electronic properties of Cs/GaAs surface are studied at elevated temperatures. • Heating to ∼100 °C strongly affects photoemission current and surface band bending. • For θ < 0.4 ML photoemission current relaxation is due to band bending. • A spectral proof of the PETE process is obtained at Cs/GaAs thermal cycling. - Abstract: The temperature influence on the Cs/GaAs surface electronic properties, which determine the photon-enhanced thermionic emission (PETE), is studied. It was found that heating to moderate temperatures of about 100 °C leads to substantial changes in the magnitude and shape of Cs coverage dependences of photoemission current and surface band bending, along with the changes of relaxation kinetics after Cs deposition. A spectral proof of the PETE process is obtained under thermal cycling of the Cs/GaAs surface with 0.45 monolayer (ML) of Cs.

Mathematical programming models for the economic design and assessment of wind energy conversion systems

Science.gov (United States)

Reinert, K. A.

The use of linear decision rules (LDR) and chance constrained programming (CCP) to optimize the performance of wind energy conversion clusters coupled to storage systems is described. Storage is modelled by LDR and output by CCP. The linear allocation rule and linear release rule prescribe the size and optimize a storage facility with a bypass. Chance constraints are introduced to explicitly treat reliability in terms of an appropriate value from an inverse cumulative distribution function. Details of deterministic programming structure and a sample problem involving a 500 kW and a 1.5 MW WECS are provided, considering an installed cost of $1/kW. Four demand patterns and three levels of reliability are analyzed for optimizing the generator choice and the storage configuration for base load and peak operating conditions. Deficiencies in ability to predict reliability and to account for serial correlations are noted in the model, which is concluded useful for narrowing WECS design options.

AN ANALYSIS OF STUDENTS’ SPEAKING ABILITY IN ENGLISH CONVERSATION CLUB (ECC PROGRAM AT THE 3rd SEMESTER

Directory of Open Access Journals (Sweden)

M. Fadhly Farhy Abbas

2017-07-01

Full Text Available This research is based on students’ speaking ability who had followed the EnglishConversation Club (ECC program especially for the third semester of English Department. Thepurpose of this study was to analyze the students’ speaking ability at the 3rd semester in the EnglishConversation Club FKIP UNILAK Pekanbaru. The type of the research was mixed method in typeof explanatory design. The number of participant was 53 students. The researcher used twoinstruments, those were test and interview. In analyzing the data, it used in descriptive statistics.The result of the analysis showed that the average score of 3rd semester students’ speaking abilitywas 45.42. It can be concluded that the students’ speaking ability was categorized into failed . Thescore of Standard Deviation was 7.02, Variance was 49.30, and Range was 36 points . It meansthat the students’ speaking ability was homogeneous. According to the Z-Score, it can be seen that49.06% students’ ability was higher than average and 50.94% students ability was below theaverage. In conclusion, the students’ ability in learning speaking English was failed, it had beenaffected by some factors, those were lack of vocabulary, grammar and motivation. It was supportedby the interview, eventhough the students’ perception to English Conversation Club (ECCprogram was positive, but in fact, the students’ frequency to speak English was seldom, they wereless practice speaking English everyday.Keywords : Speaking , English Conversation Club (ECC

Concept of Lunar Energy Park

Science.gov (United States)

Niino, Masayuki; Kisara, Katsuto; Chen, Lidong

1993-10-01

This paper presents a new concept of energy supply system named Lunar Energy Park (LEP) as one of the next-generation clean energy sources. In this concept, electricity is generated by nuclear power plants built on the moon and then transmitted to receiving stations on the earth by laser beam through transporting systems situated in geostationary orbit. The lunar nuclear power plants use a high-efficiency composite energy conversion system consisting of thermionic and thermoelectric generators to change nuclear thermal energy into electricity directly. The nuclear resources are considered to be available from the moon, and nuclear fuel transport from earth to moon is not necessary. Because direct energy conversion systems are employed, the lunar nuclear plants can be operated and controlled by robots and are maintenance-free, and so will cause no pollution to humans. The key technologies for LEP include improvements of conversion efficiency of both thermionic and thermoelectric converters, and developments of laser-beam power transmission technology as well. The details, including the construction of lunar nuclear plants, energy conversion and energy transmission systems, as well as the research plan strategies for this concept are reviewed.

Environmental Development Plan: uranium mining, milling, and conversion

International Nuclear Information System (INIS)

1979-08-01

This Environmental Development Plan (EDP) identifies the planning and management requirements and schedules needed to evaluate and assess the environmental, health, and safety (EH and S) aspects of the uranium mining, milling, and conversion technologies. The plan represents the collective perceptions of EH and S concerns and requirements and knowledge of ongoing research programs of most of the Federal agencies involved in significant EH and S R and D program management, standards setting, or regulatory activities associated with uranium mining, milling, and conversion

TET_2MCNP: A conversion program to implement tetrahearal-mesh models in MCNP

International Nuclear Information System (INIS)

Han, Min Cheol; Yeom, Yeon Soo; Nguyen, Thng Tat; Choi, Chan Soo; Lee, Hyun Su; Kim, Chan Hyeong

2016-01-01

Tetrahedral-mesh geometries can be used in the MCNP code, but the MCNP code accepts only the geometry in the Abaqus input file format; hence, the existing tetrahedral-mesh models first need to be converted to the Abacus input file format to be used in the MCNP code. In the present study, we developed a simple but useful computer program, TET_2MCNP, for converting TetGen-generated tetrahedral-mesh models to the Abacus input file format. TET_2MCNP is written in C++ and contains two components: one for converting a TetGen output file to the Abacus input file and the other for the reverse conversion process. The TET_2MCP program also produces an MCNP input file. Further, the program provides some MCNP-specific functions: the maximum number of elements (i.e., tetrahedrons) per part can be limited, and the material density of each element can be transferred to the MCNP input file. To test the developed program, two tetrahedral-mesh models were generated using TetGen and converted to the Abaqus input file format using TET_2MCNP. Subsequently, the converted files were used in the MCNP code to calculate the object- and organ-averaged absorbed dose in the sphere and phantom, respectively. The results show that the converted models provide, within statistical uncertainties, identical dose values to those obtained using the PHITS code, which uses the original tetrahedral-mesh models produced by the TetGen program. The results show that the developed program can successfully convert TetGen tetrahedral-mesh models to Abacus input files. In the present study, we have developed a computer program, TET_2MCNP, which can be used to convert TetGen-generated tetrahedral-mesh models to the Abaqus input file format for use in the MCNP code. We believe this program will be used by many MCNP users for implementing complex tetrahedral-mesh models, including computational human phantoms, in the MCNP code

Development of a thermionic magnicon amplifier at 11.4 GHz

International Nuclear Information System (INIS)

Gold, S.H.; Hafizi, B.; Fliflet, A.W.; Kinkead, A.K.; True, R.

1997-01-01

The magnicon is a scanning-beam microwave amplifier tube that is being developed as an rf source for the proposed TeV Next Linear Collider. In it, a solid electron beam is spun up to high transverse momentum in a series of deflection cavities containing synchronously rotating TM modes, and then spun down again in an output cavity whose mode is synchronous with that of the deflection cavities. A recent magnicon experiment at NRL, using a ∼ 650 kV, 225 A, 5.5-mm-diam. electron beam produced from a cold cathode driven by a single-shot Marx generator, demonstrated 14 MW (±3 dB) at 11.12 GHz with 105 efficiency in the synchronous magnicon mode, but was limited by plasma loading in the deflection cavities to a regime in which the last cavity of the deflection system (the penultimate cavity) was unstable. A new 11.4 GHz rep-rated thermionic magnicon experiment is being assembled, using an advanced ultra-high-convergence electron gun driven by a 10 Hz, 1.5 microsecond modulator top produce a 500 kV, 210 A, 2-mm diameter electron beam. The magnicon circuit has been optimized for minimum surface rf fields and maximum efficiency, and will be engineered for high temperature bakeout and high vacuum operation. This experiment should begin operation in the Summer of 1997. The predicted power is 60 MW at ∼ 60% efficiency

Energy and cost savings results for advanced technology systems from the Cogeneration Technology Alternatives Study /CTAS/

Science.gov (United States)

Sagerman, G. D.; Barna, G. J.; Burns, R. K.

1979-01-01

The Cogeneration Technology Alternatives Study (CTAS), a program undertaken to identify the most attractive advanced energy conversion systems for industrial cogeneration applications in the 1985-2000 time period, is described, and preliminary results are presented. Two cogeneration options are included in the analysis: a topping application, in which fuel is input to the energy conversion system which generates electricity and waste heat from the conversion system is used to provide heat to the process, and a bottoming application, in which fuel is burned to provide high temperature process heat and waste heat from the process is used as thermal input to the energy conversion system which generates energy. Steam turbines, open and closed cycle gas turbines, combined cycles, diesel engines, Stirling engines, phosphoric acid and molten carbonate fuel cells and thermionics are examined. Expected plant level energy savings, annual energy cost savings, and other results of the economic analysis are given, and the sensitivity of these results to the assumptions concerning fuel prices, price of purchased electricity and the potential effects of regional energy use characteristics is discussed.

Development of a coherent transition radiation-based bunch length monitor with application to the APS RF thermionic gun beam optimization

CERN Document Server

Lumpkin, Alex H; Berg, W J; Borland, M; Happek, U; Lewellen, J W; Sereno, N S

2001-01-01

We report further development of an EPICS-compatible bunch length monitor based on the autocorrelation of coherent transition radiation (CTR). In this case the monitor was used to optimize the beam from the S-band thermionic RF gun on the Advanced Photon Source (APS) linac. Bunch lengths of 400-500 fs (FWHM) were measured in the core of the beam, which corresponded to about 100-A peak current in each micropulse. The dependence of the CTR signal on the square of the beam charge for the beam core was demonstrated. We also report the first use of the beam accelerated to 217 MeV for successful visible wavelength SASE FEL experiments.

Biomass Thermochemical Conversion Program. 1983 Annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1984-08-01

Highlights of progress achieved in the program of thermochemical conversion of biomass into clean fuels during 1983 are summarized. Gasification research projects include: production of a medium-Btu gas without using purified oxygen at Battelle-Columbus Laboratories; high pressure (up to 500 psia) steam-oxygen gasification of biomass in a fluidized bed reactor at IGT; producing synthesis gas via catalytic gasification at PNL; indirect reactor heating methods at the Univ. of Missouri-Rolla and Texas Tech Univ.; improving the reliability, performance, and acceptability of small air-blown gasifiers at Univ. of Florida-Gainesville, Rocky Creek Farm Gasogens, and Cal Recovery Systems. Liquefaction projects include: determination of individual sequential pyrolysis mechanisms at SERI; research at SERI on a unique entrained, ablative fast pyrolysis reactor for supplying the heat fluxes required for fast pyrolysis; work at BNL on rapid pyrolysis of biomass in an atmosphere of methane to increase the yields of olefin and BTX products; research at the Georgia Inst. of Tech. on an entrained rapid pyrolysis reactor to produce higher yields of pyrolysis oil; research on an advanced concept to liquefy very concentrated biomass slurries in an integrated extruder/static mixer reactor at the Univ. of Arizona; and research at PNL on the characterization and upgrading of direct liquefaction oils including research to lower oxygen content and viscosity of the product. Combustion projects include: research on a directly fired wood combustor/gas turbine system at Aerospace Research Corp.; adaptation of Stirling engine external combustion systems to biomass fuels at United Stirling, Inc.; and theoretical modeling and experimental verification of biomass combustion behavior at JPL to increase biomass combustion efficiency and examine the effects of additives on combustion rates. 26 figures, 1 table.

Natural gas conversion program of Rio de Janeiro-Brazil; Projeto de conversao do sistema de distribuicao de gas canalizado na cidade do Rio de Janeiro

Energy Technology Data Exchange (ETDEWEB)

Pallottino, J.T.; Costa Filho, M.A.F.; Guarana, L.F.M.L. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Margalef, J.M. [Companhia Estadual de Gas (CEG), Rio de Janeiro, RJ (Brazil)

2008-07-01

This paper presents the Conversion Project of Rio de Janeiro, Brazil, that converted all customers and the distribution network from Manufactured Gas (MG) to Natural Gas (NG), evaluating its logistic and benefits, highlighting those related to consumer safety. The Conversion Project was executed under the responsibility of CEG with the support of UERJ, specially on the definition and revision of the technical procedures as well as the quality assurance of the project execution. As main advantages followed by MG to NG network conversion, we can note: increasing of gas distribution network capacity and gas network operational condition improvements; elimination of production plant; revision and renovation of gas network; revision and repairing of building gas facilities; augmenting of NG usage; elimination of carbon monoxide as a supplied gas constituent. Conservation condition of most consumer internal gas facilities and ambient ventilation were so critical that conversion program resulted in no measurable accident prevention. The achieved safety level should be maintained through a periodically re-evaluation program of customer's gas facilities and appliances, with special focus on permanent ventilation required for NG safety usage. (author)

Conversion Rate Optimization : Visual Neuro Programming Principles

OpenAIRE

Berezhnaya, Anastasia

2016-01-01

The influence of the world wide web has already spread in every business. Consequently, it has become crucial to develop strong online presence and offer qualified user experience for website visitors. Website optimization undeniably has proved its importance in the recent decade. This research was conducted in order to study the practical application and structure of the stages of the CRO (Conversion Rate Optimization) framework that focuses on the most representative website metric – c...

Online Education: Let's Start the Conversation

Science.gov (United States)

Dixon, Robert J.

2017-01-01

National shortages of school psychologists have started conversations about training, the number of training programs needed, and how to initiate new programs. This article discusses the difficulties associated with traditional training programs for school psychologists and proposes exploring online education and virtual school psychology service…

Characterization of sputter deposited thin film scandate cathodes for miniaturized thermionic converter applications

Science.gov (United States)

Zavadil, Kevin R.; Ruffner, Judith H.; King, Donald B.

1999-01-01

We have successfully developed a method for fabricating scandate-based thermionic emitters in thin film form. The primary goal of our effort is to develop thin film emitters that exhibit low work function, high intrinsic electron emissivity, minimum thermal activation properties and that can be readily incorporated into a microgap converter. Our approach has been to incorporate BaSrO into a Sc2O3 matrix using rf sputtering to produce thin films. Diode testing has shown the resulting films to be electron emissive at temperatures as low as 900 K with current densities of 0.1 mA.cm-2 at 1100 K and saturation voltages. We calculate an approximate maximum work function of 1.8 eV and an apparent emission constant (Richardson's constant, A*) of 36 mA.cm-2.K-2. Film compositional and structural analysis shows that a significant surface and subsurface alkaline earth hydroxide phase can form and probably explains the limited utilization and stability of Ba and its surface complexes. The flexibility inherent in sputter deposition suggests alternate strategies for eliminating undesirable phases and optimizing thin film emitter properties.

Environmental monitoring handbook for coal conversion facilities

Energy Technology Data Exchange (ETDEWEB)

Salk, M.S.; DeCicco, S.G. (eds.)

1978-05-01

The primary objectives of the Department of Energy's (DOE) coal conversion program are to demonstrate the environmental acceptability, technical feasibility, and economic viability of various technologies for gaseous, liquid, and solid fuels from coal. The Environmental Monitoring Handbook for Coal Conversion Facilities will help accomplish the objective of environmental acceptability by guiding the planning and execution of socioeconomic and environmental monitoring programs for demonstration facilities. These programs will provide information adequate to (1) predict, insofar as is possible, the potential impacts of construction and operation of a coal conversion plant, (2) verify the occurrence of these or any other impacts during construction and operation, (3) determine the adequacy of mitigating measures to protect the environment, (4) develop effluent source terms for process discharges, and (5) determine the effectiveness of pollution control equipment. Although useful in a variety of areas, the handbook is intended primarily for contractors who, as industrial partners with DOE, are building coal conversion plants. For the contractor it is a practical guide on (1) the methodology for developing site- and process-specific environmental monitoring programs, (2) state-of-the-art sampling and analytical techniques, and (3) impact analyses.To correspond to the phases of project activity, the subject matter is divided into four stages of monitoring: (1) a reconnaissance or synoptic survey, (2) preconstruction or baseline, (3) construction, and (4) operation, including process monitoring (prepared by Radian Corp., McLean, Va.). For each stage of monitoring, guidelines are given on socioeconomics, aquatic and terrestrial ecology, air quality and meteorology, surface and groundwater quality, geohydrology and soil survey, and surface water hydrology.

Conversational interfaces for task-oriented spoken dialogues: design aspects influencing interaction quality

NARCIS (Netherlands)

Niculescu, A.I.

2011-01-01

This dissertation focuses on the design and evaluation of speech-based conversational interfaces for task-oriented dialogues. Conversational interfaces are software programs enabling interaction with computer devices through natural language dialogue. Even though processing conversational speech is

National Conversion Pilot Project Waste Management Program

International Nuclear Information System (INIS)

Engelmann, G.G.; Simmons, M.S.

1995-01-01

The U.S. Department of Energy facilities are in the process of downsizing. Most plans for downsizing focus on the decontamination and decommissioning of excess production facilities. A different approach for downsizing is taken at Rocky Flats Environmental Technology Site (RFETS), which has four production buildings. These buildings were used for the production of weapons components from uranium and beryllium and contain unique and valuable equipment, such as rolling mills, furnaces, and high-capacity presses, which could be utilized for stage-III metal recycling. The mission of this National Conversion Pilot Project (NCPP) open-quotes is to explore and demonstrate, at the Rocky Flats Environmental Technology Site (RFETS), the feasibility of economic conversion at Department of Energy facilities.close quotes The NCPP has been divided into three stages: 1. Stage I-planning and feasibility determination 2. Stage II-facility cleanup for reuse and operational assessment 3. Stage III-metals recycling. The NCPP has recently been approved to begin stage II. The objective of the NCPP stage II is to prepare the four NCPP buildings for stage III, to remove unwanted equipment, and to decontaminate buildings and essential equipment to levels consistent with those that commercial industrial operations must meet pursuant to applicable Occupational Safety and Health Administration, U.S. Environmental Protection Agency, U.S. Nuclear Regulatory Commission, and state workplace regulations

Status of conversion of NE standards to national consensus standards

International Nuclear Information System (INIS)

Jennings, S.D.

1990-06-01

One major goal of the Nuclear Standards Program is to convert existing NE standards into national consensus standards (where possible). This means that an NE standard in the same subject area using the national consensus process. This report is a summary of the activities that have evolved to effect conversion of NE standards to national consensus standards, and the status of current conversion activities. In some cases, all requirements in an NE standard will not be incorporated into the published national consensus standard because these requirements may be considered too restrictive or too specific for broader application by the nuclear industry. If these requirements are considered necessary for nuclear reactor program applications, the program standard will be revised and issued as a supplement to the national consensus standard. The supplemental program standard will contain only those necessary requirements not reflected by the national consensus standard. Therefore, while complete conversion of program standards may not always be realized, the standards policy has been fully supported in attempting to make maximum use of the national consensus standard. 1 tab

TET{sub 2}MCNP: A conversion program to implement tetrahearal-mesh models in MCNP

Energy Technology Data Exchange (ETDEWEB)

Han, Min Cheol; Yeom, Yeon Soo; Nguyen, Thng Tat; Choi, Chan Soo; Lee, Hyun Su; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

2016-12-15

Tetrahedral-mesh geometries can be used in the MCNP code, but the MCNP code accepts only the geometry in the Abaqus input file format; hence, the existing tetrahedral-mesh models first need to be converted to the Abacus input file format to be used in the MCNP code. In the present study, we developed a simple but useful computer program, TET{sub 2}MCNP, for converting TetGen-generated tetrahedral-mesh models to the Abacus input file format. TET{sub 2}MCNP is written in C++ and contains two components: one for converting a TetGen output file to the Abacus input file and the other for the reverse conversion process. The TET{sub 2}MCP program also produces an MCNP input file. Further, the program provides some MCNP-specific functions: the maximum number of elements (i.e., tetrahedrons) per part can be limited, and the material density of each element can be transferred to the MCNP input file. To test the developed program, two tetrahedral-mesh models were generated using TetGen and converted to the Abaqus input file format using TET{sub 2}MCNP. Subsequently, the converted files were used in the MCNP code to calculate the object- and organ-averaged absorbed dose in the sphere and phantom, respectively. The results show that the converted models provide, within statistical uncertainties, identical dose values to those obtained using the PHITS code, which uses the original tetrahedral-mesh models produced by the TetGen program. The results show that the developed program can successfully convert TetGen tetrahedral-mesh models to Abacus input files. In the present study, we have developed a computer program, TET{sub 2}MCNP, which can be used to convert TetGen-generated tetrahedral-mesh models to the Abaqus input file format for use in the MCNP code. We believe this program will be used by many MCNP users for implementing complex tetrahedral-mesh models, including computational human phantoms, in the MCNP code.

40 CFR Appendix B to Part 72 - Methodology for Conversion of Emissions Limits

Science.gov (United States)

2010-07-01

... site-specific heat rates and capacities to develop conversions for Btu per hour. Standard conversion... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Methodology for Conversion of... Conversion of Emissions Limits For the purposes of the Acid Rain Program, all emissions limits must be...

Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs

Energy Technology Data Exchange (ETDEWEB)

Yoder, G.L.

2005-10-03

This report documents the work performed during the first phase of the National Aeronautics and Space Administration (NASA), National Research Announcement (NRA) Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs. The document includes an optimization of both 100-kW{sub e} and 250-kW{sub e} (at the propulsion unit) Rankine cycle power conversion systems. In order to perform the mass optimization of these systems, several parametric evaluations of different design options were investigated. These options included feed and reheat, vapor superheat levels entering the turbine, three different material types, and multiple heat rejection system designs. The overall masses of these Nb-1%Zr systems are approximately 3100 kg and 6300 kg for the 100- kW{sub e} and 250-kW{sub e} systems, respectively, each with two totally redundant power conversion units, including the mass of the single reactor and shield. Initial conceptual designs for each of the components were developed in order to estimate component masses. In addition, an overall system concept was presented that was designed to fit within the launch envelope of a heavy lift vehicle. A technology development plan is presented in the report that describes the major efforts that are required to reach a technology readiness level of 6. A 10-year development plan was proposed.

ECUT: Energy Conversion and Utilization Technologies program. Industry, university and research interest in the US Department of Energy ECUT biocatalysis research activity

Science.gov (United States)

Wilcox, R. E.

1983-01-01

The results of a Research Opportunity Notice (RON) disseminated by the Jet Propulsion Laboratory for the U.S. Department of Energy Conversion and Utilization Technologies (ECUT) Program's Biocatalysis Research Activity are presented. The RON was issued in late April of 1983 and solicited expressions of interest from petrochemical and chemical companies, bioengineering firms, biochemical engineering consultants, private research laboratories, and universities for participating in a federal research program to investigate potential applications of biotechnology in producing chemicals. The RON results indicate that broad interest exists within the nation's industry, universities, and research institutes for the Activity and its planned research and development program.

TFTR power conversion and plasma feedback systems

International Nuclear Information System (INIS)

Neumeyer, C.

1985-01-01

Major components of the Tokamak Fusion Test Reactor (TFTR) power conversion system include 39 thyristor rectifier power supplies, 12 energy storage capacitor banks, and 6 ohmic heating interrupters. These components are connected in various series/parallel configurations to provide controlled pulses of current to the Toroidal Field (TF), Ohmic Heating (OH), Equilibrium (vertical) Field (EF), and Horizontal Field (HF) magnet coil systems. Real-time control of the power conversion system is accomplished by a centralized dedicated computer; local control is minimal. Power supply firing angles, capacitor bank charge and discharge commands, interrupter commands, etc., are all determined and issued by the central computer. Plasma Position and Current Control (PPCC) reference signals to power conversion (OH, EF, HF) are determined by separate analog electronics but invoked through the power conversion computer. Real-time fault sensing of plasma parameters, gas injection, neutral beams, etc., are monitored by a separate Discharge Fault System (DFS) but routed through the power conversion computer for pre-programmed shutdown response

Turning Content into Conversation: How The GLOBE Program is Growing its Brand Online

Science.gov (United States)

Zwerin, R.; Randolph, J. G.; Andersen, T.; Mackaro, J.; Malmberg, J.; Tessendorf, S. A.; Wegner, K.

2012-12-01

Social Media is now a ubiquitous way for individuals, corporations, governments and communities to communicate. However, the same does not hold quite as true for the science community as many science educators, thought leaders and science programs are either reluctant or unable to build and cultivate a meaningful social media strategy. This presentation will show how The GLOBE Program uses social media to disseminate messages, build a meaningful and engaged following and grow a brand on an international scale using a proprietary Inside-Out strategy that leverages social media platforms such as Facebook, LinkedIn, Twitter, YouTube and Blogs to significantly increase influencers on a worldwide scale. In addition, this poster presentation will be interactive, so viewers will be able to touch and feel the social experience. Moreover, GLOBE representatives will be on hand to talk viewers through how they can implement a social media strategy that will allow them to turn their content into meaningful conversation. About The GLOBE Program: GLOBE is a science and education program that connects a network of students, teachers and scientists from around the world to better understand, sustain and improve Earth's environment at local, regional and global scales. By engaging students in hands-on learning of Earth system science, GLOBE is an innovative way for teachers to get students of all ages excited about scientific discovery locally and globally. To date, more than 23 million measurements have been contributed to the GLOBE database, creating meaningful, standardized, global research-quality data sets that can be used in support of student and professional scientific research. Since beginning operations in 1995, over 58,000 trained teachers and 1.5 million students in 112 countries have participated in GLOBE. For more information or to become involved, visit www.globe.gov.

Cost-Effectiveness of Emissions Reduction through Vehicle Repair Compared to CNG Conversion.

Science.gov (United States)

Guenther, Paul L; Lesko, Jon M; Stedman, Donald H

1996-10-01

In return for a temporary waiver from converting five vehicles to operate on compressed natural gas (CNG) for the Denver Clean Fuels program, the University of Denver identified, tested, repaired, and retested nine employee commuter vehicles. The results of the study validated the concept that employer-based identification and repair programs can be carried out in a cost-effective way. On average, each repaired vehicle removed fifty times more carbon monoxide (CO) emissions from Denver air than each CNG conversion. The average cost of each repair was eight times less than the average cost of each conversion. The average fuel economy benefit from the repairs was enough to pay for the average cost of repairs in less than three years of normal driving. When the expected lifetimes of repairs and conversions are included, the targeted repair program appears to be over sixty times more cost-effective as a CO emissions reduction strategy than CNG conversion.

Conversions Rock! Lessons & Worksheets to Build Skills in Equivalent Conversions. Poster/Teaching Guide. Expect the Unexpected with Math[R

Science.gov (United States)

Actuarial Foundation, 2013

2013-01-01

"Welcome to Conversions Rock" is a new math program designed to build and reinforce the important skills of converting fractions, decimals, and percents for students in grades 6-8. Developed by The Actuarial Foundation, this program seeks to provide skill-building, real-world math to help students become successful in the classroom and beyond. [A…

Thermoelectron corporation: From space power to Fortune 500

Science.gov (United States)

Scoville, A. Nancy; Masters, Richard

1995-01-01

ThermoElectron Corporation was founded in 1957 to commercialize thermionic energy conversion technologies. Today the company is a Fortune 500 company with 1993 revenues of 1.2 billion. In this paper the methods ThermoElectron used to achieve this result will be discussed with emphasis on the corporate philosophy.

Analysis of internal conversion coefficients

International Nuclear Information System (INIS)

Coursol, N.; Gorozhankin, V.M.; Yakushev, E.A.; Briancon, C.; Vylov, Ts.

2000-01-01

An extensive database has been assembled that contains the three most widely used sets of calculated internal conversion coefficients (ICC): [Hager R.S., Seltzer E.C., 1968. Internal conversion tables. K-, L-, M-shell Conversion coefficients for Z=30 to Z=103, Nucl. Data Tables A4, 1-237; Band I.M., Trzhaskovskaya M.B., 1978. Tables of gamma-ray internal conversion coefficients for the K-, L- and M-shells, 10≤Z≤104, Special Report of Leningrad Nuclear Physics Institute; Roesel F., Fries H.M., Alder K., Pauli H.C., 1978. Internal conversion coefficients for all atomic shells, At. Data Nucl. Data Tables 21, 91-289] and also includes new Dirac-Fock calculations [Band I.M. and Trzhaskovskaya M.B., 1993. Internal conversion coefficients for low-energy nuclear transitions, At. Data Nucl. Data Tables 55, 43-61]. This database is linked to a computer program to plot ICCs and their combinations (sums and ratios) as a function of Z and energy, as well as relative deviations of ICC or their combinations for any pair of tabulated data. Examples of these analyses are presented for the K-shell and total ICCs of the gamma-ray standards [Hansen H.H., 1985. Evaluation of K-shell and total internal conversion coefficients for some selected nuclear transitions, Eur. Appl. Res. Rept. Nucl. Sci. Tech. 11.6 (4) 777-816] and for the K-shell and total ICCs of high multipolarity transitions (total, K-, L-, M-shells of E3 and M3 and K-shell of M4). Experimental data sets are also compared with the theoretical values of these specific calculations

Transition to chaos in periodically driven thermionic diodes at low pressure

International Nuclear Information System (INIS)

Klinger, T.; Timm, R.; Piel, A.

1992-01-01

The static I(U) characteristic of thermionic diodes at mbar pressures shows a large hysteresis, which describes the transition from the 'anode-glow-mode' (AGM), with essentially negative plasma potential, to the 'temperature-limited-mode' (TLM), with positive plasma potential. Many features of these modes are also found in magnetic-box discharges with filament cathodes at pressures of 10 -2 -10 -1 Pa. Although these two pressure regimes are basically different concerning the transport properties (diffusion vs. free streaming), the elementary processes that establish the AGM in the low pressure regime are very similar to the high pressure regime. Ions are produced in that part of the anode sheath where the potential exceeds the ionization energy. The production rate is enhanced by multiple reflections of electrons between the magnetic fields of the permanent magnet array at the anode and the repulsive potential of the cathode plasma. Although the mean free path for charge exchange or elastic collisions substantially exceeds the anode-cathode distance, some few ions are stopped and trapped within the potential well of the virtual cathode. This accumulation of ions forms a cathodic plasma, which is essentially at cathode potential. Plasma formation in the anode sheath is suppressed as long as the ion production time is larger than the ion transit time through the sheath. These model ideas are supported by 1d-Particle-in-cell simulations using a modified PDP1-code. The AGM is attractive for studies of nonlinear dynamics because of its feedback processes and oscillations, which occur close to the hysteresis point. (author) 7 refs., 3 figs

Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

Science.gov (United States)

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

A search for space energy alternatives

Science.gov (United States)

Gilbreath, W. P.; Billman, K. W.

1978-01-01

This paper takes a look at a number of schemes for converting radiant energy in space to useful energy for man. These schemes are possible alternatives to the currently most studied solar power satellite concept. Possible primary collection and conversion devices discussed include the space particle flux devices, solar windmills, photovoltaic devices, photochemical cells, photoemissive converters, heat engines, dielectric energy conversion, electrostatic generators, plasma solar collectors, and thermionic schemes. Transmission devices reviewed include lasers and masers.

The Finmeccania experience in military conversion

International Nuclear Information System (INIS)

Airaghi, A.; Corsi, C.

1994-01-01

Experience of the Italian aerospace, defense, energy, transportation and automation group Finmeccanica in military conversion is presented. The defence activities represent about 30% of the total turnover. The group involves 100 laboratories, 7000 fully dedicated employees and several centers of excellence. Since defense market is declining, production volumes are smaller, there is a decline in research and development public expenditures and there are less programs. The industry's challenge is how to survive since conversion in principle is not viable and diversification does not defend the high technology content. Some examples are described which show the possibility of convergence from military to commercial requirements

Mechanisms of Ectopic Gene Conversion

Directory of Open Access Journals (Sweden)

P.J. Hastings

2010-11-01

Full Text Available Gene conversion (conversion, the unidirectional transfer of DNA sequence information, occurs as a byproduct of recombinational repair of broken or damaged DNA molecules. Whereas excision repair processes replace damaged DNA by copying the complementary sequence from the undamaged strand of duplex DNA, recombinational mechanisms copy similar sequence, usually in another molecule, to replace the damaged sequence. In mitotic cells the other molecule is usually a sister chromatid, and the repair does not lead to genetic change. Less often a homologous chromosome or homologous sequence in an ectopic position is used. Conversion results from repair in two ways. First, if there was a double-strand gap at the site of a break, homologous sequence will be used as the template for synthesis to fill the gap, thus transferring sequence information in both strands. Second, recombinational repair uses complementary base pairing, and the heteroduplex molecule so formed is a source of conversion, both as heteroduplex and when donor (undamaged template information is retained after correction of mismatched bases in heteroduplex. There are mechanisms that favour the use of sister molecules that must fail before ectopic homology can be used. Meiotic recombination events lead to the formation of crossovers required in meiosis for orderly segregation of pairs of homologous chromosomes. These events result from recombinational repair of programmed double-strand breaks, but in contrast with mitotic recombination, meiotic recombinational events occur predominantly between homologous chromosomes, so that transfer of sequence differences by conversion is very frequent. Transient recombination events that do not form crossovers form both between homologous chromosomes and between regions of ectopic homology, and leave their mark in the occurrence of frequent non-crossover conversion, including ectopic conversion.

Having "The Talk": Youth-Parent Climate Conversations

Science.gov (United States)

Anderson, R. K.; Flora, J. A.; Lertzman, R.; Saphir, M.

2017-12-01

Youth are concerned about climate change. Recent research conducted by the Alliance for Climate Education, in partnership with the Skoll Global Threats Fund, demonstrates that youth have agency within their families regarding climate relevant behaviors, particularly resulting from conversations that rely on listening. In this pilot project, we examined whether youth involved in a year-long climate action program will carry out climate related conversations with their parents, and whether youth who have engaged online with a climate education group, will carry out similar conversations with their parents when asked to do so via SMS. In study one, we used mixed methods to determine if youth participating in a training would carry out a climate conversation with their parents, adhere to guidelines such as reflective listening, and have positive experiences. Further, we investigated to what extent parents would experience the conversation as a positive and impactful event. Parents overall reported a positive experience, and were proud of their child's work. In study two, in a randomized controlled trial conducted entirely via SMS, we investigated whether youth would watch a brief instructional animated video, and have a conversation with a parent. Results showed the majority of youth reported gained confidence in conducting a climate conversation and intended to speak to relatives. Preliminary results indicate when youth can express their climate engagement to a parent using these techniques, they have positive experiences, gain confidence in future engagements and can influence family. The studies highlight the positive impact of climate conversations as well as the potential to scale climate conversations to reach more youth and families.

RF study and 3-D simulations of a side-coupling thermionic RF-gun

International Nuclear Information System (INIS)

Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

2014-01-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012 © . RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance

RF study and 3-D simulations of a side-coupling thermionic RF-gun

Science.gov (United States)

Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

2014-02-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

Modeling transient thermal hydraulic behavior of a thermionic fuel element for nuclear space reactors

International Nuclear Information System (INIS)

Al-Kheliewi, A.S.; Klein, A.C.

1994-01-01

A transient code (TFETC) for determining the temperature distribution throughout the radial and axial positions of a thermionic fuel element (TFE) during changes in operating conditions has been successfully developed and tested. A fully implicit method is used to solve the system of equations for temperatures at each time step. Presently, TFETC has the ability to handle the following transients: startup, loss of flow accidents, and shutdown. The code has been applied to the startup of the ATI single cell configuration which appears to start up and shut down in an orderly and reasonable fashion. No unexpected transient features were observed. The TFE also appears to function robustly under loss of flow accident conditions. It appears hat sufficient time is available to shut the reactor down safely without melting point the fuel. The model shows that during a complete loss of flow accident (without shutdown) the coolant reaches its boiling point in approximately 35 seconds. The fuel may exceed its melting point after this time as the NaK coolant will boil if the reactor is not shut down. For 1/2, 1/3, and 1/4 pump failures, the fuel temperatures never exceed the fuel melting point even if the reactor is not shut down

Research reactor core conversion programmes, Department of Research and Isotopes, International Atomic Energy Agency

International Nuclear Information System (INIS)

Muranaka, R.G.

1985-01-01

In order to put the problem of core conversion into perspective, statistical information on research reactors on a global scale is presented (from IAEA Research reactor Data Base). This paper describes the research reactor core conversion program of the Department of Research and Isotopes. Technical committee Meetings were held on the subject of research reactor core conversion since 1978, and results of these meetings are published in TECDOC-233, TECDOC-324, TECDOC-304. Additional publications are being prepared, several missions of experts have visited countries to discuss and help to plan core conversion programs; training courses and seminars were organised; IAEA has supported attendance of participants from developing countries to RERTR Meetings

Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 1, Overview

Energy Technology Data Exchange (ETDEWEB)

Butner, R.S.; Elliott, D.C.; Sealock, L.J. Jr.; Pyne, J.W.

1988-12-01

Pacific Northwest Laboratory has completed an initial investigation of the effects of physical and chemical properties of biomass feedstocks relative to their performance in biomass energy conversion systems. Both biochemical conversion routes (anaerobic digestion and ethanol fermentation) and thermochemical routes (combustion, pyrolysis, and gasification) were included in the study. Related processes including chemical and physical pretreatment to improve digestibility, and size and density modification processes such as milling and pelletizing were also examined. This overview report provides background and discussion of feedstock and conversion relationships, along with recommendations for future research. The recommendations include (1) coordinate production and conversion research programs; (2) quantify the relationship between feedstock properties and conversion priorities; (3) develop a common framework for evaluating and characterizing biomass feedstocks; (4) include conversion effects as part of the criteria for selecting feedstock breeding programs; and (5) continue emphasis on multiple feedstock/conversion options for biomass energy systems. 9 refs., 3 figs., 2 tabs.

Program Design of JSON to Structured Data Conversion

Directory of Open Access Journals (Sweden)

Da Zhongyue

2017-01-01

Full Text Available With the maturity of structured data storage technology and the increasing demand for enterprise information development, some enterprises need to convert the data storage model of application system from JSON to structured data. A file management system is token as an example to explain how to convert. In this article, it is achieved through the following three parts. First, the structure diagram of data transformation is built. Then, JSON model and structured data model are built. Finally, the conversion of data from JSON to MySQL is realized by using java language.

Planning Document for an NBSR Conversion Safety Analysis Report

Energy Technology Data Exchange (ETDEWEB)

Diamond D. J.; Baek J.; Hanson, A.L.; Cheng, L-Y.; Brown, N.; Cuadra, A.

2013-09-25

The NIST Center for Neutron Research (NCNR) is a reactor-laboratory complex providing the National Institute of Standards and Technology (NIST) and the nation with a world-class facility for the performance of neutron-based research. The heart of this facility is the National Bureau of Standards Reactor (NBSR). The NBSR is a heavy water moderated and cooled reactor operating at 20 MW. It is fueled with high-enriched uranium (HEU) fuel elements. A Global Threat Reduction Initiative (GTRI) program is underway to convert the reactor to low-enriched uranium (LEU) fuel. This program includes the qualification of the proposed fuel, uranium and molybdenum alloy foil clad in an aluminum alloy, and the development of the fabrication techniques. This report is a planning document for the conversion Safety Analysis Report (SAR) that would be submitted to, and approved by, the Nuclear Regulatory Commission (NRC) before the reactor could be converted.This report follows the recommended format and content from the NRC codified in NUREG-1537, “Guidelines for Preparing and Reviewing Applications for the Licensing of Non-power Reactors,” Chapter 18, “Highly Enriched to Low-Enriched Uranium Conversions.” The emphasis herein is on the SAR chapters that require significant changes as a result of conversion, primarily Chapter 4, Reactor Description, and Chapter 13, Safety Analysis. The document provides information on the proposed design for the LEU fuel elements and identifies what information is still missing. This document is intended to assist ongoing fuel development efforts, and to provide a platform for the development of the final conversion SAR. This report contributes directly to the reactor conversion pillar of the GTRI program, but also acts as a boundary condition for the fuel development and fuel fabrication pillars.

Irradiation behaviour of UO2/Mo porous cermets for thermionic converters

International Nuclear Information System (INIS)

Stora, J.P.; Kauffmann, Y.

1975-01-01

Two types of UO 2 Mo porous cernets have been fabricated and irradiated in a Cythere irradiation device. The first cermet is constituted by little bits of dense fuel in which the two constituants are finely dispersed. The whole open porosity is located between the granules. This type of cermet is called breche (33.4vol%UO 2 , 51vol%Mo, 14.8vol%porosity). At the end of the irradiation the burn up was 19000MWd/t(U) and neither swelling of the cermet nor deformation of the can were noted. On the contrary, a shrinkage of the emitter was observed attributed to a fuel densification under irradiation. The second type of cermet is called macrogranule (36vol%UO 2 , 49vol%Mo 15vol%porosity). UO 2 granules of 0.07cm mean diameter are dispersed in the molybdenum matrix. The porosity is regularly distributed all around the UO 2 kernels. The post irradiation metrology shows that the emitter is fairly stable. Only a slight ovalisation of about 0.5% was noted, but the granules of UO 2 were redistributed inside the molybdenum matrix, overlapping the metallic cavity by a condensation-evaporation process. The matrix has crept into the central void and consequently the volume has grown and the whole porosity has increased from about 15% to about 23%. This creeping is due to the fission gas pressure in the molybdenum cavities after 3000 hours of irradiation. In conclusion two types of cermets have shown good behaviour under irradiation and should allow lifetimes of several thousand hours of operation for thermionic fuel elements [fr

Biomass Program 2007 Program Peer Review - Thermochemical Conversion Platform Summary

Energy Technology Data Exchange (ETDEWEB)

none,

2009-10-27

This document discloses the comments provided by a review panel at the U.S. Department of Energy Office of the Biomass Program Peer Review held on November 15-16, 2007 in Baltimore, MD and the Biomass Program Peer Review for the Thermochemical Platform, held on July 9th and 10th in Golden, Colorado.

Pronunciation and Conversation Challenges among Saudi EFL Students

Directory of Open Access Journals (Sweden)

Issa Mohammad Muflih Naser

2018-04-01

Full Text Available This study aims to identify the difficulties of pronunciation and conversation faced by EFL learners who undertook a Preparatory Year Program (PYP in Saudi Arabia, It highlights the main issues in pronunciation and conversations (e.g., textbooks, teaching methods, and students' attitude and motivation and techniques to address these problems. The instruments used in the study were classroom observations and teachers' discussions. The results revealed that firstly, students did not have a sound knowledge of grammar. Secondly, students' outside environment was influenced by their mother tongue. Thirdly, the teaching methods did not suit their proficiency levels. Finally, they were demotivated and thought that they have an impossible mission to improve their English pronunciation and conversation.

Conversion projects program plan WBS 7.4.9. Revision 1

International Nuclear Information System (INIS)

1995-09-01

The mission of Conversion Projects (CP) is to transfer physical, intellectual, human and fiscal resources that advance the Hanford cleanup mission, support new missions, and that may inherently also benefit the economic transition of the region. This implements Function 6.0 of the Hanford Cleanup Technical Baseline

Alternative model of space-charge-limited thermionic current flow through a plasma

Science.gov (United States)

Campanell, M. D.

2018-04-01

It is widely assumed that thermionic current flow through a plasma is limited by a "space-charge-limited" (SCL) cathode sheath that consumes the hot cathode's negative bias and accelerates upstream ions into the cathode. Here, we formulate a fundamentally different current-limited mode. In the "inverse" mode, the potentials of both electrodes are above the plasma potential, so that the plasma ions are confined. The bias is consumed by the anode sheath. There is no potential gradient in the neutral plasma region from resistivity or presheath. The inverse cathode sheath pulls some thermoelectrons back to the cathode, thereby limiting the circuit current. Thermoelectrons entering the zero-field plasma region that undergo collisions may also be sent back to the cathode, further attenuating the circuit current. In planar geometry, the plasma density is shown to vary linearly across the electrode gap. A continuum kinetic planar plasma diode simulation model is set up to compare the properties of current modes with classical, conventional SCL, and inverse cathode sheaths. SCL modes can exist only if charge-exchange collisions are turned off in the potential well of the virtual cathode to prevent ion trapping. With the collisions, the current-limited equilibrium must be inverse. Inverse operating modes should therefore be present or possible in many plasma devices that rely on hot cathodes. Evidence from past experiments is discussed. The inverse mode may offer opportunities to minimize sputtering and power consumption that were not previously explored due to the common assumption of SCL sheaths.

Investigation of barium-calcium aluminate process to manufacture and characterize impregnated thermionic cathode for power microwave devices

International Nuclear Information System (INIS)

Higashi, Cristiane

2006-01-01

In the present work it is described the barium calcium aluminate manufacture processes employed to produce impregnated cathodes to be used in a traveling-wave tube (TWT). The cathodes were developed using a tungsten body impregnated with barium and calcium aluminate with a 5:3:2 proportion (molar). Three different processes were investigated to obtain this material: solid-state reaction, precipitation and crystallization. Thermal analysis, thermogravimetry specifically, supported to determine an adequate preparation procedure (taking into account temperature, time and pyrolysis atmosphere). It was verified that the crystallization showed a better result when compared to those investigated (solid-state reaction and precipitation techniques - formation temperature is about 1000 deg C in hydrogen atmosphere), whereas it presented the lower formation temperature (800 deg C) in oxidizing atmosphere (O 2 ). It was used the practical work function distribution theory (PWFD) of Miram to characterize thermionic impregnated cathode. The PWFD curves were used to characterize the barium-calcium aluminate cathode. PWFD curves shown that the aluminate cathode work function is about 2,00 eV. (author)

Trade study for kWe class space reactors

Science.gov (United States)

Bost, Donald S.

Recent interest by NASA and other government agencies in space reactor power systems with power levels in the 1 to 100 kWe range has prompted a review of earlier space reactor programs, as well as the ongoing SP-100 program, to identify a system that will best fulfill their needs. The candidate reactor types that were reviewed are listed. They are categorized according to the method of heat removal. The five types are: conduction cooled, heat pipe cooled, liquid metal cooled, in-core thermionic and gas cooled. The UZrH moderated reactor coupled with an organic Rankine cycle power conversion system provides an attractive system for multikilowatt, long lived missions. The reactor requires a minimum development because a similar reactor has already flown and the ORC is being developed for use in the Dynamic Isotope Power System (DIPS) and on the Space Station.

Sixth underground coal-conversion symposium

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

The sixth annual underground coal conversion symposium was held at Shangri-la near Afton, Oklahoma, July 13 to 17, 1980. Sessions were developed to: Doe Field Programs, Major Industry Activity, Mathematical Modeling, Laboratory Studies, Environmental Studies, Economics, Instruments and Controls, and General Topics. Fifty-two papers from the proceedings have been entered individually into EDB and ERA. Thirteen papers had been entered previously from other sources. (LTN)

RF study and 3-D simulations of a side-coupling thermionic RF-gun

Energy Technology Data Exchange (ETDEWEB)

Rimjaem, S., E-mail: sakhorn.rimjaem@cmu.ac.th [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand); Kusoljariyakul, K.; Thongbai, C. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand)

2014-02-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012{sup ©}. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

Static and dynamic high power, space nuclear electric generating systems

International Nuclear Information System (INIS)

Wetch, J.R.; Begg, L.L.; Koester, J.K.

1985-01-01

Space nuclear electric generating systems concepts have been assessed for their potential in satisfying future spacecraft high power (several megawatt) requirements. Conceptual designs have been prepared for reactor power systems using the most promising static (thermionic) and the most promising dynamic conversion processes. Component and system layouts, along with system mass and envelope requirements have been made. Key development problems have been identified and the impact of the conversion process selection upon thermal management and upon system and vehicle configuration is addressed. 10 references

Status of LEU fuel development and conversion of NRU

International Nuclear Information System (INIS)

Sears, D.F.; Herbert, L.N.; Vaillancourt, K.D.

1991-01-01

This paper reviews the status of the LEU conversion program and the progress made in the fuel development program over the last year. The results from post-irradiation examinations of prototype NRU fuel rods containing Al-U 3 Si dispersion fuel, and of mini-elements containing Al-U 3 Si 2 dispersion fuel, are presented. (orig.)

77 FR 23273 - Proposed Information Collection; Comment Request: Home Equity Conversion Mortgage Counseling...

Science.gov (United States)

2012-04-18

... Collection; Comment Request: Home Equity Conversion Mortgage Counseling Client Survey AGENCY: Office of the... information: Title of Proposal: Home Equity Conversion Mortgage Counseling Client Survey. OMB Control Number... reverse mortgage counseling. As part of HUD's evaluation of its HECM counseling program, performance...

Effect of yield and price risk on conversion from conventional to organic farming

NARCIS (Netherlands)

Acs, S.; Berentsen, P.B.M.; Huirne, R.B.M.; Asseldonk, van M.A.P.M.

2009-01-01

Although the benefits of organic farming are already well known, the conversion to organic farming does not proceed as the Dutch government expected. In order to investigate the conversion decisions of Dutch arable farms, a discrete stochastic dynamic utility-efficient programming (DUEP) model is

Recommended programming practices to facilitate the portability of science computer programs

International Nuclear Information System (INIS)

Anon.

1983-01-01

This standard recommends programming practices to facilitate the portability of computer programs prepared for scientific and engineering computations. These practices are intended to simplify implementation, conversion, and modification of computer programs

Perspectives for the uranium conversion market

International Nuclear Information System (INIS)

Honaiser, Eduardo H.R.; Melo, Bruno

2007-01-01

Uranium conversion is the last step to be technologically dominated by Brazil in the nuclear fuel cycle. Hence, it has a strategic importance for the Brazilian nuclear project, which is confirmed by the recent investment of the Science and Technology Department on the Brazilian Navy conversion plant project. This paper is an attempt to justify the necessity of the conversion and the Brazilian nuclear fuel cycle projects, as well as identify future steps for the Brazilian nuclear fuel cycle project. The paper objective is achieved performing a qualitative supply-demand balance for the past and the future and analysing the market structure, using the Porter five forces used on industry analysis. Both surveys have shown a promising future for the nuclear fuel industry, including the conversion due to the expected demand increase and reduction of inventories. Furthermore current suppliers have several mechanisms that work as a barrier to new entrants. Under this context, the a fully integrated Brazilian nuclear fuel cycle project is necessary, given the prosperous economical future of the sector and the possible future shortage of nuclear fuel products. Reprocessing and MOX fuel fabrication capabilities are important future steps for the program, given that there is a trend of increase of their use. (author)

Perspectives for the uranium conversion market

Energy Technology Data Exchange (ETDEWEB)

Honaiser, Eduardo H.R.; Melo, Bruno [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)]. E-mail: 213@ctemsp.mar.mil.br

2007-07-01

Uranium conversion is the last step to be technologically dominated by Brazil in the nuclear fuel cycle. Hence, it has a strategic importance for the Brazilian nuclear project, which is confirmed by the recent investment of the Science and Technology Department on the Brazilian Navy conversion plant project. This paper is an attempt to justify the necessity of the conversion and the Brazilian nuclear fuel cycle projects, as well as identify future steps for the Brazilian nuclear fuel cycle project. The paper objective is achieved performing a qualitative supply-demand balance for the past and the future and analysing the market structure, using the Porter five forces used on industry analysis. Both surveys have shown a promising future for the nuclear fuel industry, including the conversion due to the expected demand increase and reduction of inventories. Furthermore current suppliers have several mechanisms that work as a barrier to new entrants. Under this context, the a fully integrated Brazilian nuclear fuel cycle project is necessary, given the prosperous economical future of the sector and the possible future shortage of nuclear fuel products. Reprocessing and MOX fuel fabrication capabilities are important future steps for the program, given that there is a trend of increase of their use. (author)

29th Intersociety energy conversion engineering conference: Technical papers. Part 1

International Nuclear Information System (INIS)

Anon.

1994-01-01

Part 1 of these proceedings contains 96 papers covering the following topics: Aircraft power; Aerospace power systems--Automation; Batteries for aerospace power; Computer modeling of spacecraft systems; Fuel cells for aerospace; Power electronics; Power management and distribution; Space solar power; Space power systems; Solar dynamic ground test demonstrator; Space nuclear systems--Applications; Space nuclear systems--Reactor technology thermionics; Space nuclear systems reactor technology--Thermoelectrics; Space nuclear systems--Bimodal propulsion; Space nuclear systems--Isotopic power; and Space nuclear systems--thermoelectric materials. Most of the papers have been processed separately for inclusion on the data base

Measurement and modeling of advanced coal conversion processes. Annual report, October 1990--September 1991

Energy Technology Data Exchange (ETDEWEB)

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. [Advanced Fuel Research, Inc., East Hartford, CT (United States)]|[Brigham Young Univ., Provo, UT (United States)

1991-12-31

The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

Advanced Radioisotope Power Conversion Technology Research and Development

Science.gov (United States)

Wong, Wayne A.

2004-01-01

NASA's Radioisotope Power Conversion Technology program is developing next generation power conversion technologies that will enable future missions that have requirements that cannot be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power System (RPS) technology. Performance goals of advanced radioisotope power systems include improvement over the state-of-practice General Purpose Heat Source/Radioisotope Thermoelectric Generator by providing significantly higher efficiency to reduce the number of radioisotope fuel modules, and increase specific power (watts/kilogram). Other Advanced RPS goals include safety, long-life, reliability, scalability, multi-mission capability, resistance to radiation, and minimal interference with the scientific payload. NASA has awarded ten contracts in the technology areas of Brayton, Stirling, Thermoelectric, and Thermophotovoltaic power conversion including five development contracts that deal with more mature technologies and five research contracts. The Advanced RPS Systems Assessment Team includes members from NASA GRC, JPL, DOE and Orbital Sciences whose function is to review the technologies being developed under the ten Radioisotope Power Conversion Technology contracts and assess their relevance to NASA's future missions. Presented is an overview of the ten radioisotope power conversion technology contracts and NASA's Advanced RPS Systems Assessment Team.

Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Conversion Pathway: Biological Conversion of Sugars to Hydrocarbons The 2017 Design Case

Energy Technology Data Exchange (ETDEWEB)

Kevin Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J Bonner; Garold L. Gresham; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

2013-09-01

The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL conducted a campaign to quantify the economics and sustainability of moving biomass from standing in the field or stand to the throat of the biomass conversion process. The goal of this program was to establish the current costs based on conventional equipment and processes, design improvements to the current system, and to mark annual improvements based on higher efficiencies or better designs. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $35/dry ton. This goal was successfully achieved in 2012 by implementing field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. Looking forward to 2017, the programmatic target is to supply biomass to the conversion facilities at a total cost of $80/dry ton and on specification with in-feed requirements. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, abundant, low-cost feedstock. If this goal is not achieved, biofuel plants are destined to be small and/or clustered in select regions of the country that have a lock on low-cost feedstock. To put the 2017 cost target into perspective of past accomplishments of the cellulosic ethanol pathway, the $80 target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all

Conversion problems at the enterprises of Georgia

International Nuclear Information System (INIS)

Khurodze, R.

1998-01-01

In the republic Georgia and other countries of former Soviet Union, various scientific research and experimental construction work for the production of special military techniques was conducted for Military Institutions. Much of the conversion work has been done and the brightest example was performed by Georgian aviation industry. Intensive research was conducted on improving the quality of the existing power systems as well as on search for new power sources and means of power savings. A number of significant projects were developed, the implementation of which will considerably improve the crisis situation in the sphere of power supply. A number of laboratories and research centres have submitted proposals for conversion programs

A Conversion Tool for Mathematical Expressions in Web XML Files.

Science.gov (United States)

Ohtake, Nobuyuki; Kanahori, Toshihiro

2003-01-01

This article discusses the conversion of mathematical equations into Extensible Markup Language (XML) on the World Wide Web for individuals with visual impairments. A program is described that converts the presentation markup style to the content markup style in MathML to allow browsers to render mathematical expressions without other programs.…

Mold heating and cooling microprocessor conversion

Science.gov (United States)

Hoffman, D. P.

1995-07-01

Conversion of the microprocessors and software for the Mold Heating and Cooling (MHAC) pump package control systems was initiated to allow required system enhancements and provide data communications capabilities with the Plastics Information and Control System (PICS). The existing microprocessor-based control systems for the pump packages use an Intel 8088-based microprocessor board with a maximum of 64 Kbytes of program memory. The requirements for the system conversion were developed, and hardware has been selected to allow maximum reuse of existing hardware and software while providing the required additional capabilities and capacity. The new hardware will incorporate an Intel 80286-based microprocessor board with an 80287 math coprocessor, the system includes additional memory, I/O, and RS232 communication ports.

Annual review in automatic programming

CERN Document Server

Halpern, Mark I; Bolliet, Louis

2014-01-01

Computer Science and Technology and their Application is an eight-chapter book that first presents a tutorial on database organization. Subsequent chapters describe the general concepts of Simula 67 programming language; incremental compilation and conversational interpretation; dynamic syntax; the ALGOL 68. Other chapters discuss the general purpose conversational system for graphical programming and automatic theorem proving based on resolution. A survey of extensible programming language is also shown.

IAEA activities related to research reactor fuel conversion and spent fuel return programs

International Nuclear Information System (INIS)

Goldman, Ira N.; Adelfang, Pablo; Ritchie, Iain G.

2005-01-01

The IAEA has been involved for more than twenty years in supporting international nuclear non-proliferation efforts associated with reducing the amount of highly enriched uranium (HEU) in international commerce. IAEA projects and activities have directly supported the Reduced Enrichment for Research and Test Reactors (RERTR) programme, as well as directly associated efforts to return research reactor fuel to the country where it was originally enriched. IAEA efforts have included the development and maintenance of several data bases with information related to research reactors and research reactor spent fuel inventories that have been essential in planning and managing both RERTR and spent fuel return programmes. Other IAEA regular budget programs have supported research reactor fuel conversion from HEU to low enriched uranium (LEU), and in addressing issues common to many member states with spent fuel management problems and concerns. The paper briefly describes IAEA involvement since the early 1980's in these areas, including regular budget and Technical Co-operation programme activities, and focuses on efforts in the past five years to continue to support and accelerate U.S. and Russian research reactor spent fuel return programmes. (author)

Low-Enriched Uranium Fuel Conversion Activities for the High Flux Isotope Reactor, Annual Report for FY 2011

Energy Technology Data Exchange (ETDEWEB)

Renfro, David G [ORNL; Cook, David Howard [ORNL; Freels, James D [ORNL; Griffin, Frederick P [ORNL; Ilas, Germina [ORNL; Sease, John D [ORNL; Chandler, David [ORNL

2012-03-01

This report describes progress made during FY11 in ORNL activities to support converting the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum (UMo) alloy. With both radial and axial contouring of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current levels achieved with HEU fuel. Studies are continuing to demonstrate that the fuel thermal safety margins can be preserved following conversion. Studies are also continuing to update other aspects of the reactor steady state operation and accident response for the effects of fuel conversion. Technical input has been provided to Oregon State University in support of their hydraulic testing program. The HFIR conversion schedule was revised and provided to the GTRI program. In addition to HFIR conversion activities, technical support was provided directly to the Fuel Fabrication Capability program manager.

Low-Enriched Uranium Fuel Conversion Activities for the High Flux Isotope Reactor, Annual Report for FY 2011

International Nuclear Information System (INIS)

Renfro, David G.; Cook, David Howard; Freels, James D.; Griffin, Frederick P.; Ilas, Germina; Sease, John D.; Chandler, David

2012-01-01

This report describes progress made during FY11 in ORNL activities to support converting the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum (UMo) alloy. With both radial and axial contouring of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current levels achieved with HEU fuel. Studies are continuing to demonstrate that the fuel thermal safety margins can be preserved following conversion. Studies are also continuing to update other aspects of the reactor steady state operation and accident response for the effects of fuel conversion. Technical input has been provided to Oregon State University in support of their hydraulic testing program. The HFIR conversion schedule was revised and provided to the GTRI program. In addition to HFIR conversion activities, technical support was provided directly to the Fuel Fabrication Capability program manager.

Irradiation experiment conceptual design parameters for MURR LEU U-Mo fuel conversion

International Nuclear Information System (INIS)

Stillman, J.; Feldman, E.; Stevens, J.; Wilson, E.

2013-03-01

This report contains the results of reactor design and performance calculations for conversion of the University of Missouri Research Reactor (MURR) from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL) and the MURR Facility. The core conversion to LEU is being performed with financial support from the U. S. government. In the framework of its non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context most research and test reactors, both domestic and international, have started a program of conversion to the use of LEU fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (U-Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MURR. This report presents the nominal steady-state irradiation conditions of a key set of plates containing peak irradiation parameters found in MURR cores fueled with the LEU monolithic U-Mo alloy fuel with 10 wt% Mo.

Selection of power plant elements for future reactor space electric power systems

International Nuclear Information System (INIS)

Buden, D.; Bennett, G.A.; Copper, K.

1979-09-01

Various types of reactor designs, electric power conversion equipment, and reject-heat systems to be used in nuclear reactor power plants for future space missions were studied. The designs included gas-cooled, liquid-cooled, and heat-pipe reactors. For the power converters, passive types such as thermoelectric and thermionic converters and dynamic types such as Brayton, potassium Rankine, and Stirling cycles were considered. For the radiators, heat pipes for transfer and radiating surface, pumped fluid for heat transfer with fins as the radiating surface, and pumped fluid for heat transfer with heat pipes as the radiating surface were considered. After careful consideration of weights, sizes, reliabilities, safety, and development cost and time, a heat-pipe reactor design, thermoelectric converters, and a heat-pipe radiator for an experimental program were selected

Conversation therapy with people with aphasia and conversation partners using video feedback: a group and case series investigation of changes in interaction.

Directory of Open Access Journals (Sweden)

Wendy Best

2016-11-01

Full Text Available Conversation therapies employing video for feedback and to facilitate outcome measurement are increasingly used with people with post-stroke aphasia and their conversation partners; however the evidence base for change in everyday interaction remains limited. We investigated the effect of Better Conversations with Aphasia, an intervention that is freely available online (https:// extend.ucl.ac.uk/. Eight people with chronic agrammatic aphasia, and their regular conversation partners participated in the tailored 8 week program involving significant video feedback. We explored changes in (i conversation facilitators (such as multi-modal turns by people with aphasia and (ii conversation barriers (such as use of test questions by conversation partners. The outcome of intervention was evaluated directly by measuring change in video-recorded everyday conversations. The study employed a pre-post design with multiple 5 minute samples of conversation before and after intervention, scored by trained raters blind to the point of data collection. Group level analysis showed no significant increase in conversation facilitators. There was, however, a significant reduction in the number of conversation barriers. The case series data revealed variability in conversation behaviors across occasions for the same dyad and between different dyads. Specifically, post-intervention there was a significant increase in facilitator behaviors for two dyads, a decrease for one and no significant change for five dyads. There was a significant decrease in barrier behaviors for five dyads and no significant change for three dyads. The reduction in barrier behaviors was considerable; on average change from over 8 to fewer than 3 barrier behaviors in 5 minutes conversation. The pre-post design has the limitation of no comparison group. However, change occurs in targeted conversational behaviors and in people with chronic aphasia and their partners. The findings suggest change

'EXTSANGLE' - an extension of the efficiency conversion program 'SOLANG' to sources with a diameter larger than that of the Ge-detector

International Nuclear Information System (INIS)

Mihaljevic, N.; Jovanovic, S.; Vukotic, P.

1993-01-01

The computer program SOLANG, originally developed by MOENS et al. for the efficiency conversion via effective solid angles (Ω-bar), was extended to cylindrical sources with a diameter larger than that of the Ge-detector. New program, named EXTSANGLE, was experimentally checked in three laboratories. For the most unfavourable case from the standpoint of the accuracy of Ω-bar (bulky source counted at the top of detector), discrepancies were below 7% in the whole range of gamma-energies considered (88-1115 keV), with an average of 3-4%. EXTSANGLE is extensive and flexible with respect to the data input, storage and output, thus contributing to the automation of a gamma-spectrometry laboratory dealing, for instance, with the k 0 -NAA and/or environmental radioactivity monitoring. (author) 9 refs.; 3 figs.; 1 tab

Monetary conversion factors for economic evaluations of substance use disorders.

Science.gov (United States)

McCollister, Kathryn; Yang, Xuan; Sayed, Bisma; French, Michael T; Leff, Jared A; Schackman, Bruce R

2017-10-01

Estimating the economic consequences of substance use disorders (SUDs) is important for evaluating existing programs and new interventions. Policy makers in particular must weigh program effectiveness with scalability and sustainability considerations in deciding which programs to fund with limited resources. This study provides a comprehensive list of monetary conversion factors for a broad range of consequences, services, and outcomes, which can be used in economic evaluations of SUD interventions (primarily in the United States), including common co-occurring conditions such as HCV and HIV. Economic measures were selected from standardized clinical assessment instruments that are used in randomized clinical trials and other research studies (e.g., quasi-experimental community-based projects) to evaluate the impact of SUD interventions. National datasets were also reviewed for additional SUD-related consequences, services, and outcomes. Monetary conversion factors were identified through a comprehensive literature review of published articles as well as targeted searches of other sources such as government reports. Eight service/consequence/outcome domains were identified containing more than sixty monetizable measures of medical and behavioral health services, laboratory services, SUD treatment, social services, productivity outcomes, disability outcomes, criminal activity and criminal justice services, and infectious diseases consequences. Unit-specific monetary conversion factors are reported, along with upper and lower bound estimates, whenever possible. Having an updated and standardized source of monetary conversion factors will facilitate and improve future economic evaluations of interventions targeting SUDs and other risky behaviors. This exercise should be repeated periodically as new sources of data become available to maintain the timeliness, comprehensiveness, and quality of these estimates. Copyright © 2017 The Authors. Published by Elsevier Inc

Uranium conversion

International Nuclear Information System (INIS)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

2006-03-01

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

A BML Based Embodied Conversational Agent for a Personality Detection Program

NARCIS (Netherlands)

Solano Méndez, Guillermo; Reidsma, Dennis; Vilhjálmsson, Hannes Högni; Kopp, Stefan; Marsella, Stacy; Thórisson, Kristinn R.

2011-01-01

This paper presents a project in which an Embodied Conversational Agent (ECA) attemtps to detect the personality of the user by asking him (or her) a series of questions. The project uses the Elckerlyc platform, a Behavior Markup Language (BML) compliant behavior realizer for ECAs [1]. BML allows

CY205 conversion of the NAMMU program

International Nuclear Information System (INIS)

Lindewall, L.

1986-02-01

The NAMMU program has been converted from an IBM double precision version to a CY205 single precision version. Due to different dialects among compilers, differences on system levels and machine dependencies some changes to the code have been made. They are documented in this report. A scalar optimized version is delivered. Direct vectorization did not improve performance. Changes in program logic is necessary to take advantage of the the vector capabilities. That and a study of the input-output operations are needed to improve performance. (author)

Direct observation of the carrier transport process in InGaN quantum wells with a pn-junction

Science.gov (United States)

Wu, Haiyan; Ma, Ziguang; Jiang, Yang; Wang, Lu; Yang, Haojun; Li, Yangfeng; Zuo, Peng; Jia, Haiqiang; Wang, Wenxin; Zhou, Junming; Liu, Wuming; Chen, Hong

2016-11-01

A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported. According to the well established light-to-electricity conversion theory, quantum wells (QWs) cannot be used in solar cells and photodetectors because the photogenerated carriers in QWs usually relax to ground energy levels, owing to quantum confinement, and cannot form a photocurrent. We observe directly that more than 95% of the photoexcited carriers escape from InGaN/GaN QWs to generate a photocurrent, indicating that the thermionic emission and tunneling processes proposed previously cannot explain carriers escaping from QWs. We show that photoexcited carriers can escape directly from the QWs when the device is under working conditions. Our finding challenges the current theory and demonstrates a new prospect for developing highly efficient solar cells and photodetectors. Project supported by the National Natural Science Foundation of China (Grant Nos. 11574362, 61210014, and 11374340) and the Innovative Clean-energy Research and Application Program of Beijing Municipal Science and Technology Commission, China (Grant No. Z151100003515001).

US energy conversion and use characteristics

Energy Technology Data Exchange (ETDEWEB)

Imhoff, C.H.; Liberman, A.; Ashton, W.B.

1982-02-01

The long-range goal of the Energy Conversion and Utilization Technology (ECUT) Program is to enhance energy productivity in all energy-use sectors by supporting research on improved efficiency and fuel switching capability in the conversion and utilization of energy. Regardless of the deficiencies of current information, a summary of the best available energy-use information is needed now to support current ECUT program planning. This document is the initial draft of this type of summary and serves as a data book that will present current and periodically updated descriptions of the following aspects of energy use: gross US energy consumption in each major energy-use sector; energy consumption by fuel type in each sector; energy efficiency of major equipment/processes; and inventories, replacement rates, and use patterns for major energy-using capital stocks. These data will help the ECUT program staff perform two vital planning functions: determine areas in which research to improve energy productivity might provide significant energy savings or fuel switching and estimate the actual effect that specific research projects may have on energy productivity and conservation. Descriptions of the data sources and examples of the uses of the different types of data are provided in Section 2. The energy-use information is presented in the last four sections; Section 3 contains general, national consumption data; and Sections 4 through 6 contain residential/commercial, industrial, and transportation consumption data, respectively. (MCW)

The Role of Conversation Policy in Carrying Out Agent Conversations

International Nuclear Information System (INIS)

Link, Hamilton E.; Phillips, Laurence R.

1999-01-01

Structured conversation diagrams, or conversation specifications, allow agents to have predictable interactions and achieve predefined information-based goals, but they lack the flexibility needed to function robustly in an unpredictable environment. We propose a mechanism that combines a typical conversation structure with a separately established policy to generate an actual conversation. The word ''policy'' connotes a high-level direction external to a specific planned interaction with the environment. Policies, which describe acceptable procedures and influence decisions, can be applied to broad sets of activity. Based on their observation of issues related to a policy, agents may dynamically adjust their communication patterns. The policy object describes limitations, constraints, and requirements that may affect the conversation in certain circumstances. Using this new mechanism of interaction simplifies the description of individual conversations and allows domain-specific issues to be brought to bear more easily during agent communication. By following the behavior of the conversation specification when possible and deferring to the policy to derive behavior in exceptional circumstances, an agent is able to function predictably under normal situations and still act rationally in abnormal situations. Different conversation policies applied to a given conversation specification can change the nature of the interaction without changing the specification

Space electric power design study. [laser energy conversion

Science.gov (United States)

Martini, W. R.

1976-01-01

The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

Conversion coefficients for individual monitoring calculated with integrated tiger series, ITS3, Monte Carlo code

International Nuclear Information System (INIS)

Devine, R.T.; Hsu, Hsiao-Hua

1994-01-01

The current basis for conversion coefficients for calibrating individual photon dosimeters in terms of dose equivalents is found in the series of papers by Grosswent. In his calculation the collision kerma inside the phantom is determined by calculation of the energy fluence at the point of interest and the use of the mass energy absorption coefficient. This approximates the local absorbed dose. Other Monte Carlo methods can be sued to provide calculations of the conversion coefficients. Rogers has calculated fluence-to-dose equivalent conversion factors with the Electron-Gamma Shower Version 3, EGS3, Monte Carlo program and produced results similar to Grosswent's calculations. This paper will report on calculations using the Integrated TIGER Series Version 3, ITS3, code to calculate the conversion coefficients in ICRU Tissue and in PMMA. A complete description of the input parameters to the program is given and comparison to previous results is included

Preconceptual design studies and cost data of depleted uranium hexafluoride conversion plants

International Nuclear Information System (INIS)

Jones, E

1999-01-01

One of the more important legacies left with the Department of Energy (DOE) after the privatization of the United States Enrichment Corporation is the large inventory of depleted uranium hexafluoride (DUF6). The DOE Office of Nuclear Energy, Science and Technology (NE) is responsible for the long-term management of some 700,000 metric tons of DUF6 stored at the sites of the two gaseous diffusion plants located at Paducah, Kentucky and Portsmouth, Ohio, and at the East Tennessee Technology Park in Oak Ridge, Tennessee. The DUF6 management program resides in NE's Office of Depleted Uranium Hexafluoride Management. The current DUF6 program has largely focused on the ongoing maintenance of the cylinders containing DUF6. However, the long-term management and eventual disposition of DUF6 is the subject of a Programmatic Environmental Impact Statement (PEIS) and Public Law 105-204. The first step for future use or disposition is to convert the material, which requires construction and long-term operation of one or more conversion plants. To help inform the DUF6 program's planning activities, it was necessary to perform design and cost studies of likely DUF6 conversion plants at the preconceptual level, beyond the PEIS considerations but not as detailed as required for conceptual designs of actual plants. This report contains the final results from such a preconceptual design study project. In this fast track, three month effort, Lawrence Livermore National Laboratory and Bechtel National Incorporated developed and evaluated seven different preconceptual design cases for a single plant. The preconceptual design, schedules, costs, and issues associated with specific DUF6 conversion approaches, operating periods, and ownership options were evaluated based on criteria established by DOE. The single-plant conversion options studied were similar to the dry-conversion process alternatives from the PEIS. For each of the seven cases considered, this report contains information on

Heat pipe nuclear reactor for space power

Science.gov (United States)

Koening, D. R.

1976-01-01

A heat-pipe-cooled nuclear reactor has been designed to provide 3.2 MWth to an out-of-core thermionic conversion system. The reactor is a fast reactor designed to operate at a nominal heat-pipe temperature of 1675 K. Each reactor fuel element consists of a hexagonal molybdenum block which is bonded along its axis to one end of a molybdenum/lithium-vapor heat pipe. The block is perforated with an array of longitudinal holes which are loaded with UO2 pellets. The heat pipe transfers heat directly to a string of six thermionic converters which are bonded along the other end of the heat pipe. An assembly of 90 such fuel elements forms a hexagonal core. The core is surrounded by a thermal radiation shield, a thin thermal neutron absorber, and a BeO reflector containing boron-loaded control drums.

In Conversation: Celia Reyes on the importance of timely economic ...

International Development Research Centre (IDRC) Digital Library (Canada)

2011-02-03

Feb 3, 2011 ... In Conversation: Celia Reyes on the importance of timely economic ... in particular, assessing the impact of policies and programs on poverty and equity. .... Tourism is an important driver of economic growth throughout ...

Review of the TREAT Conversion Conceptual Design and Fuel Qualification Plan

Energy Technology Data Exchange (ETDEWEB)

Diamond, David

2017-12-29

The U.S. Department of Energy (DOE) is preparing to re establish the capability to conduct transient testing of nuclear fuels at the Idaho National Laboratory (INL) Transient Reactor Test (TREAT) facility. The original TREAT core went critical in February 1959 and operated for more than 6,000 reactor startups before plant operations were suspended in 1994. DOE is now planning to restart the reactor using the plant's original high-enriched uranium (HEU) fuel. At the same time, the National Nuclear Security Administration (NNSA) Office of Material Management and Minimization Reactor Conversion Program is supporting analyses and fuel fabrication studies that will allow for reactor conversion to low-enriched uranium (LEU) fuel (i.e., fuel with less than 20% by weight 235U content) after plant restart. The TREAT Conversion Program's objectives are to perform the design work necessary to generate an LEU replacement core, to restore the capability to fabricate TREAT fuel element assemblies, and to implement the physical and operational changes required to convert the TREAT facility to use LEU fuel.

RSMASS system model development

International Nuclear Information System (INIS)

Marshall, A.C.; Gallup, D.R.

1998-01-01

RSMASS system mass models have been used for more than a decade to make rapid estimates of space reactor power system masses. This paper reviews the evolution of the RSMASS models and summarizes present capabilities. RSMASS has evolved from a simple model used to make rough estimates of space reactor and shield masses to a versatile space reactor power system model. RSMASS uses unique reactor and shield models that permit rapid mass optimization calculations for a variety of space reactor power and propulsion systems. The RSMASS-D upgrade of the original model includes algorithms for the balance of the power system, a number of reactor and shield modeling improvements, and an automatic mass optimization scheme. The RSMASS-D suite of codes cover a very broad range of reactor and power conversion system options as well as propulsion and bimodal reactor systems. Reactor choices include in-core and ex-core thermionic reactors, liquid metal cooled reactors, particle bed reactors, and prismatic configuration reactors. Power conversion options include thermoelectric, thermionic, Stirling, Brayton, and Rankine approaches. Program output includes all major component masses and dimensions, efficiencies, and a description of the design parameters for a mass optimized system. In the past, RSMASS has been used as an aid to identify and select promising concepts for space power applications. The RSMASS modeling approach has been demonstrated to be a valuable tool for guiding optimization of the power system design; consequently, the model is useful during system design and development as well as during the selection process. An improved in-core thermionic reactor system model RSMASS-T is now under development. The current development of the RSMASS-T code represents the next evolutionary stage of the RSMASS models. RSMASS-T includes many modeling improvements and is planned to be more user-friendly. RSMASS-T will be released as a fully documented, certified code at the end of

Power conversion technologies

Energy Technology Data Exchange (ETDEWEB)

Newton, M. A.

1997-02-01

The Power Conversion Technologies thrust area identifies and sponsors development activities that enhance the capabilities of engineering at Lawrence Livermore National Laboratory (LLNL) in the area of solid- state power electronics. Our primary objective is to be a resource to existing and emerging LLNL programs that require advanced solid-state power electronic technologies.. Our focus is on developing and integrating technologies that will significantly impact the capability, size, cost, and reliability of future power electronic systems. During FY-96, we concentrated our research efforts on the areas of (1) Micropower Impulse Radar (MIR); (2) novel solid-state opening switches; (3) advanced modulator technology for accelerators; (4) compact accelerators; and (5) compact pulse generators.

Grandeurs, dimensions, et conversions d'unités Quantities, Dimensions and Units Conversions

Directory of Open Access Journals (Sweden)

Bronner C.

2006-11-01

also included in this article. Undoubtedly, the best help will be found in the program included in a floppy disk. A software, in the Windows environment will enable whoever wants to solve, its units conversion problem accurately. The conversion technique, based on dimensional analysis, is used in the program and explained in this article.

Accident Analyses for Conversion of the University of Missouri Research Reactor (MURR) from Highly-Enriched to Low-Enriched Uranium

Energy Technology Data Exchange (ETDEWEB)

Stillman, J. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Feldman, E. E. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Wilson, E. H. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Div., Research and Test Reactor Dept.; Foyto, L. P. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Kutikkad, K. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; McKibben, J. C. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Peters, N. J. [Univ. of Missouri, Columbia, MO (United States). Research Reactor; Cowherd, W. M. [Univ. of Missouri, Columbia, MO (United States). College of Engineering, Nuclear Engineering Program; Rickman, B. [Univ. of Missouri, Columbia, MO (United States). College of Engineering, Nuclear Engineering Program

2014-12-01

This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. This report contains the results of reactor accident analyses for the University of Missouri Research Reactor (MURR). The calculations were performed as part of the conversion from the use of highly-enriched uranium (HEU) fuel to the use of low-enriched uranium (LEU) fuel. The analyses were performed by staff members of the Global Threat Reduction Initiative (GTRI) Reactor Conversion Program at the Argonne National Laboratory (ANL), the MURR Facility, and the Nuclear Engineering Program – College of Engineering, University of Missouri-Columbia. The core conversion to LEU is being performed with financial support from the U. S. government. In the framework of non-proliferation policies, the international community presently aims to minimize the amount of nuclear material available that could be used for nuclear weapons. In this geopolitical context most research and test reactors, both domestic and international, have started a program of conversion to the use of LEU fuel. A new type of LEU fuel based on an alloy of uranium and molybdenum (U-Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MURR. This report presents the results of a study of core behavior under a set of accident conditions for MURR cores fueled with HEU U-Alx dispersion fuel or LEU monolithic U-Mo alloy fuel with 10 wt% Mo

Improvement of skeleton conversion in ICRP reference phantom conversion project

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhao Jun; Yeom, Yeon Soo; Thang, Nguyen Tat; Kim, Han Sung; Han, Min Cheol; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of); Kim, Seong Hoon [Dept. of Radiation Oncology, College of Medicine, Hanyang University, Seoul (Korea, Republic of)

2014-11-15

In the previous skeleton conversion, most bones were directly converted from the ICRP voxel phantoms by using the 3D rendering method whereas several complex-shape bones (cranium, ribs, spines, feet, and hands) were not able to be directly converted. We alternatively employed the corresponding well-defined polygonal models and attempted to adjust them to match the voxel models. However, this approach was unsatisfactory. The shapes of the alternative models were significantly different from those of the voxel models, making it virtually impossible to exactly match the voxel models as shown in Fig. 3 (left). In order to overcome the difficulty in the complex bone conversion, the present study developed a new conversion method and converted these complex bones voxel models of the ICRP male phantom to polygonal models. The present study developed the new conversion method and successfully improved polygonal models for cranium, ribs, and spines for the ICRP male phantom. The new conversion method will be also applied to the complex bone conversion for the ICRP female phantom as well as other complex organ conversion in the future.

Improvement of skeleton conversion in ICRP reference phantom conversion project

International Nuclear Information System (INIS)

Wang, Zhao Jun; Yeom, Yeon Soo; Thang, Nguyen Tat; Kim, Han Sung; Han, Min Cheol; Kim, Chan Hyeong; Kim, Seong Hoon

2014-01-01

In the previous skeleton conversion, most bones were directly converted from the ICRP voxel phantoms by using the 3D rendering method whereas several complex-shape bones (cranium, ribs, spines, feet, and hands) were not able to be directly converted. We alternatively employed the corresponding well-defined polygonal models and attempted to adjust them to match the voxel models. However, this approach was unsatisfactory. The shapes of the alternative models were significantly different from those of the voxel models, making it virtually impossible to exactly match the voxel models as shown in Fig. 3 (left). In order to overcome the difficulty in the complex bone conversion, the present study developed a new conversion method and converted these complex bones voxel models of the ICRP male phantom to polygonal models. The present study developed the new conversion method and successfully improved polygonal models for cranium, ribs, and spines for the ICRP male phantom. The new conversion method will be also applied to the complex bone conversion for the ICRP female phantom as well as other complex organ conversion in the future

Development of conversion programs for formats of thermodynamic databases

International Nuclear Information System (INIS)

Yoshida, Yasushi; Yui, Mikazu

2003-02-01

Programs which enable to convert the database format from PHREEQE code to PHREEQC, EQ3/6 and Geochemist's Workbench code were developed and quality of these programs was checked. As a result, it was confirmed that these programs converted the database format correctly except for specific conditions which lead errors. (author)

Development of a novel thermionic RF electron gun applied on a compact THz-FEL facility

Science.gov (United States)

Hu, T. N.; Pei, Y. J.; Qin, B.; Liu, K. F.; Feng, G. Y.

2018-04-01

The current requirements from civil and commercial applications lead to the development of compact free-electron laser (FEL)-based terahertz (THz) radiation sources. A picosecond electron gun plays an important role in an FEL-THz facility and attracts significant attention, as machine performance is very sensitive to initial conditions. A novel thermionic gun with an external cathode (EC) and two independently tunable cavities (ITCs) has been found to be a promising alternative to conventional electron sources due to its remarkable characteristics, and correspondingly an FEL injector can achieve a balance between a compact layout and high brightness benefitting from the velocity bunching properties and RF focusing effects in the EC-ITC gun. Nevertheless, the EC-ITC gun has not been extensively examined as part of the FEL injector in the past years. In this regard, to fill this gap, a development focusing on the experimental setup of an FEL injector based on an EC-ITC gun is described in detail. Before assembly, dynamic beam simulations were performed to investigate the optimal mounting position for the Linac associated with the focusing coils, and a suitable radio-frequency (RF) system was established based on a power coupling design and allocation. The testing bench proved to be fully functional through basic experiments using typical diagnostic approaches for estimating primary parameters. Associated with dynamic beam calculations, a performance evaluation for an EC-ITC gun was established while providing indirect testing results for an FEL injector.

The Properties of Binary and Ternary Ti Based Coatings Produced by Thermionic Vacuum Arc (TVA Technology

Directory of Open Access Journals (Sweden)

Aurelia Mandes

2018-03-01

Full Text Available A series of the multicomponent thin films (binary: Ti-C; Ti-Ag and ternary: Ti-C-Ag; Ti-C-Al were fabricated by Thermionic Vacuum Arc (TVA technology in order to study the wear resistance and the anticorrosion properties. The effects of Ti amount on the microstructure, tribological and morphological properties were subsequently investigated. TVA is an original deposition method using a combination of anodic arc and electron gun systems for the growth of films. The samples were characterized using scanning electron microscope (SEM and a transmission electron microscope (TEM accompanied by selected area electron diffraction (SAED. Tribological properties were studied by a ball-on-disc tribometer in the dry regime and the wettability was assessed by measuring the contact angle with the See System apparatus. Wear Rate results indicate an improved sliding wear behavior for Ti-C-Ag: 1.31 × 10−7 mm3/N m (F = 2 N compared to Ti-C-Al coating wear rate: 4.24 × 10−7 mm3/N m. On the other hand, by increasing the normal load to 3 N an increase to the wear rate was observed for Ti-C-Ag: 2.58 × 10−5 mm3 compared to 2.33 × 10−6 mm3 for Ti-C-Al coating.

Development of high-current-density LAB6 thermionic emitters for a space-charge-limited electron gun

International Nuclear Information System (INIS)

Herniter, M.E.; Getty, W.D.

1987-01-01

An electron gun has been developed for investigation of high current density, space charge limited operation of a lenthanum hexaboride (LaB 6 ) thermionic cathode. The 2.8 cm 2 cathode disk is heated by electron bombardment from a tungsten filament. For LaB 6 cathode temperatures greater than 1600 0 C it has been found that evaporation from the LaB 6 causes an increase in the tungsten filament emission, leading to an instability in the bombardment heating system. This instability has been investigated and eliminated by using a graphite disk in place of the LaB 6 cathode or by shielding the filament from the LaB 6 cathode by placing the LaB 6 in a graphite cup and bombarding the cup. The graphite disk has been heated to 1755 0 C with 755 W of heating power, and the shielded LaB 6 cathode has been heated to 1695 0 C. This temperature range is required for emission current densities in the 30 Acm 2 range. It is believed that the evaporation of lanthanum lowers the tungsten work function. In electron-gun use, the LaB 6 cathode has been operated up to 6.7 Acm 2 at 36 kV. A 120 kV Marx generator has been built to allow operation up to 40 Acm 2

Structural and Mechanical Properties of Nanostructured C-Ag Thin Films Synthesized by Thermionic Vacuum Arc Method

Directory of Open Access Journals (Sweden)

Rodica Vladoiu

2018-01-01

Full Text Available Nanostructured C-Ag thin films of 200 nm thickness were successfully synthesized by the Thermionic Vacuum Arc (TVA method. The influence of different substrates (glass, silicon wafers, and stainless steel on the microstructure, morphology, and mechanical properties of nanostructured C-Ag thin films was characterized by High-Resolution Transmission Electron Microscopy (HRTEM, Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM, and TI 950 (Hysitron nanoindenter equipped with Berkovich indenter, respectively. The film’s hardness deposited on glass (HC-Ag/Gl = 1.8 GPa was slightly lower than in the case of the C-Ag film deposited on a silicon substrate (HC-Ag/Si = 2.2 GPa. Also the apparent elastic modulus Eeff was lower for C-Ag/Gl sample (Eeff = 100 GPa than for C-Ag/Si (Eeff = 170 GPa, while the values for average roughness are Ra=2.9 nm (C-Ag/Si and Ra=10.6 (C-Ag/Gl. Using the modulus mapping mode, spontaneous and indentation-induced aggregation of the silver nanoparticles was observed for both C-Ag/Gl and C-Ag/Si samples. The nanocomposite C-Ag film exhibited not only higher hardness and effective elastic modulus, but also a higher fracture resistance toughness to the silicon substrate compared to the glass substrate.

Discourse analysis: Conversational analysis of the internal conversation in Oracle Corporation Malaysia

Directory of Open Access Journals (Sweden)

Marwa Marwa

2017-07-01

Full Text Available This study highlights the internal conversation which takes place in Oracle CorporationMalaysia. Through the study, it will be shown how conversational analysis is used toanalyze the transcription of a telephone conversation between Oracle staffs. The analysisof the transcriptions will apply a few basic concepts of conversational analysis; turntakingorganization, and the adjacency pair. The objective of the study is to find out howthe internal conversations takes place by focusing on the conversation itself, that is, theconversational structures spontaneously produced by people during talk ranging fromturn-taking strategies, how topics are introduced, conversation closings and so on. Bylooking in detail at such talk, we can gain a detailed understanding of how the staffs seethemselves in relation to the company that influence their daily lives.Keywords: conversational analysis, turn-taking, adjacency pairs

The role of conversation in health care interventions: enabling sensemaking and learning.

Science.gov (United States)

Jordan, Michelle E; Lanham, Holly J; Crabtree, Benjamin F; Nutting, Paul A; Miller, William L; Stange, Kurt C; McDaniel, Reuben R

2009-03-13

Those attempting to implement changes in health care settings often find that intervention efforts do not progress as expected. Unexpected outcomes are often attributed to variation and/or error in implementation processes. We argue that some unanticipated variation in intervention outcomes arises because unexpected conversations emerge during intervention attempts. The purpose of this paper is to discuss the role of conversation in shaping interventions and to explain why conversation is important in intervention efforts in health care organizations. We draw on literature from sociolinguistics and complex adaptive systems theory to create an interpretive framework and develop our theory. We use insights from a fourteen-year program of research, including both descriptive and intervention studies undertaken to understand and assist primary care practices in making sustainable changes. We enfold these literatures and these insights to articulate a common failure of overlooking the role of conversation in intervention success, and to develop a theoretical argument for the importance of paying attention to the role of conversation in health care interventions. Conversation between organizational members plays an important role in the success of interventions aimed at improving health care delivery. Conversation can facilitate intervention success because interventions often rely on new sensemaking and learning, and these are accomplished through conversation. Conversely, conversation can block the success of an intervention by inhibiting sensemaking and learning. Furthermore, the existing relationship contexts of an organization can influence these conversational possibilities. We argue that the likelihood of intervention success will increase if the role of conversation is considered in the intervention process. The generation of productive conversation should be considered as one of the foundations of intervention efforts. We suggest that intervention facilitators

The role of conversation in health care interventions: enabling sensemaking and learning

Directory of Open Access Journals (Sweden)

Stange Kurt C

2009-03-01

Full Text Available Abstract Background Those attempting to implement changes in health care settings often find that intervention efforts do not progress as expected. Unexpected outcomes are often attributed to variation and/or error in implementation processes. We argue that some unanticipated variation in intervention outcomes arises because unexpected conversations emerge during intervention attempts. The purpose of this paper is to discuss the role of conversation in shaping interventions and to explain why conversation is important in intervention efforts in health care organizations. We draw on literature from sociolinguistics and complex adaptive systems theory to create an interpretive framework and develop our theory. We use insights from a fourteen-year program of research, including both descriptive and intervention studies undertaken to understand and assist primary care practices in making sustainable changes. We enfold these literatures and these insights to articulate a common failure of overlooking the role of conversation in intervention success, and to develop a theoretical argument for the importance of paying attention to the role of conversation in health care interventions. Discussion Conversation between organizational members plays an important role in the success of interventions aimed at improving health care delivery. Conversation can facilitate intervention success because interventions often rely on new sensemaking and learning, and these are accomplished through conversation. Conversely, conversation can block the success of an intervention by inhibiting sensemaking and learning. Furthermore, the existing relationship contexts of an organization can influence these conversational possibilities. We argue that the likelihood of intervention success will increase if the role of conversation is considered in the intervention process. Summary The generation of productive conversation should be considered as one of the foundations of

Reflector drums as control mechanism for craft thermionic reactors with constant emitter heating containing U-233 as fuel and beryllium as moderator

International Nuclear Information System (INIS)

Sahin, S.; Selvi, S.

1980-01-01

The suitability of borated reflector drums has been investigated and shown as a control mechanism for space craft thermionic reactors with constant emitter heating using U-233 as fuel and beryllium to be moderator, mainly due to their extremce compactness and their very soft neutron sepctrum. The achievable change in ksub(eff) allows long-term control operation with success. The use of reflector drums keeps the cone diameter and the mass of the radiation shield on minimum. The distortion of the emitter heating field remains under acceptable tolerances, mainly due to the enhanced neutron production at the outer core region and the remaining reflector part between the boron layer and the core. All neutron physics calculations have been carried out using the multigroup Ssub(N) methods. Three data groups for r-theta-calculations in S 4 -P 1 approximation (16 space angles) have been evaluated from a 123-energy-groups data library using transport theoretical methods. (orig.) [de

Dissecting engineered cell types and enhancing cell fate conversion via CellNet

Science.gov (United States)

Morris, Samantha A.; Cahan, Patrick; Li, Hu; Zhao, Anna M.; San Roman, Adrianna K.; Shivdasani, Ramesh A.; Collins, James J.; Daley, George Q.

2014-01-01

SUMMARY Engineering clinically relevant cells in vitro holds promise for regenerative medicine, but most protocols fail to faithfully recapitulate target cell properties. To address this, we developed CellNet, a network biology platform that determines whether engineered cells are equivalent to their target tissues, diagnoses aberrant gene regulatory networks, and prioritizes candidate transcriptional regulators to enhance engineered conversions. Using CellNet, we improved B cell to macrophage conversion, transcriptionally and functionally, by knocking down predicted B cell regulators. Analyzing conversion of fibroblasts to induced hepatocytes (iHeps), CellNet revealed an unexpected intestinal program regulated by the master regulator Cdx2. We observed long-term functional engraftment of mouse colon by iHeps, thereby establishing their broader potential as endoderm progenitors and demonstrating direct conversion of fibroblasts into intestinal epithelium. Our studies illustrate how CellNet can be employed to improve direct conversion and to uncover unappreciated properties of engineered cells. PMID:25126792

Systems modeling for a laser-driven IFE power plant using direct conversion

International Nuclear Information System (INIS)

Meier, W R

2008-01-01

A variety of systems analyses have been conducted for laser driver IFE power plants being developed as part of the High Average Power Laser (HAPL) program. A key factor determining the economics attractiveness of the power plant is the net power conversion efficiency which increases with increasing laser efficiency, target gain and fusion-to-electric power conversion efficiency. A possible approach to increasing the power conversion efficiency is direct conversion of ionized target emissions to electricity. This study examines the potential benefits of increased efficiency when the expanding plasma is inductively coupled to an external circuit allowing some of the ion energy to be directly converted to electricity. For base case direct-drive targets with approximately 24% of the target yield in ions, the benefits are modest, especially for chamber designs that operate at high temperature and thus already have relatively high thermal conversion efficiencies. The reduction in the projected cost of electricity is ∼5-10%

Optimal fleet conversion policy from a life cycle perspective

International Nuclear Information System (INIS)

Hyung Chul Kim; Ross, M.H.; Keoleian, G.A.

2004-01-01

Vehicles typically deteriorate with accumulating mileage and emit more tailpipe air pollutants per mile. Although incentive programs for scrapping old, high-emitting vehicles have been implemented to reduce urban air pollutants and greenhouse gases, these policies may create additional sales of new vehicles as well. From a life cycle perspective, the emissions from both the additional vehicle production and scrapping need to be addressed when evaluating the benefits of scrapping older vehicles. This study explores an optimal fleet conversion policy based on mid-sized internal combustion engine vehicles in the US, defined as one that minimizes total life cycle emissions from the entire fleet of new and used vehicles. To describe vehicles' lifetime emission profiles as functions of accumulated mileage, a series of life cycle inventories characterizing environmental performance for vehicle production, use, and retirement was developed for each model year between 1981 and 2020. A simulation program is developed to investigate ideal and practical fleet conversion policies separately for three regulated pollutants (CO, NMHC, and NO x ) and for CO 2 . According to the simulation results, accelerated scrapping policies are generally recommended to reduce regulated emissions, but they may increase greenhouse gases. Multi- objective analysis based on economic valuation methods was used to investigate trade-offs among emissions of different pollutants for optimal fleet conversion policies. (author)

Status of conversion of DOE standards to non-Government standards

Energy Technology Data Exchange (ETDEWEB)

Moseley, H.L.

1992-07-01

One major goal of the DOE Technical Standards Program is to convert existing DOE standards into non-Government standards (NGS's) where possible. This means that a DOE standard may form the basis for a standards-writing committee to produce a standard in the same subject area using the non-Government standards consensus process. This report is a summary of the activities that have evolved to effect conversion of DOE standards to NGSs, and the status of current conversion activities. In some cases, all requirements in a DOE standard will not be incorporated into the published non-Government standard because these requirements may be considered too restrictive or too specific for broader application by private industry. If requirements in a DOE standard are not incorporated in a non-Government standard and the requirements are considered necessary for DOE program applications, the DOE standard will be revised and issued as a supplement to the non-Government standard. The DOE standard will contain only those necessary requirements not reflected by the non-Government standard. Therefore, while complete conversion of DOE standards may not always be realized, the Department's technical standards policy as stated in Order 1300.2A has been fully supported in attempting to make maximum use of the non-Government standard.

Status of conversion of DOE standards to non-Government standards

Energy Technology Data Exchange (ETDEWEB)

Moseley, H.L.

1992-07-01

One major goal of the DOE Technical Standards Program is to convert existing DOE standards into non-Government standards (NGS`s) where possible. This means that a DOE standard may form the basis for a standards-writing committee to produce a standard in the same subject area using the non-Government standards consensus process. This report is a summary of the activities that have evolved to effect conversion of DOE standards to NGSs, and the status of current conversion activities. In some cases, all requirements in a DOE standard will not be incorporated into the published non-Government standard because these requirements may be considered too restrictive or too specific for broader application by private industry. If requirements in a DOE standard are not incorporated in a non-Government standard and the requirements are considered necessary for DOE program applications, the DOE standard will be revised and issued as a supplement to the non-Government standard. The DOE standard will contain only those necessary requirements not reflected by the non-Government standard. Therefore, while complete conversion of DOE standards may not always be realized, the Department`s technical standards policy as stated in Order 1300.2A has been fully supported in attempting to make maximum use of the non-Government standard.

SEGY to ASCII: Conversion and Plotting Program

Science.gov (United States)

Goldman, Mark R.

1999-01-01

This report documents a computer program to convert standard 4 byte, IBM floating point SEGY files to ASCII xyz format. The program then optionally plots the seismic data using the GMT plotting package. The material for this publication is contained in a standard tar file (of99-126.tar) that is uncompressed and 726 K in size. It can be downloaded by any Unix machine. Move the tar file to the directory you wish to use it in, then type 'tar xvf of99-126.tar' The archive files (and diskette) contain a NOTE file, a README file, a version-history file, source code, a makefile for easy compilation, and an ASCII version of the documentation. The archive files (and diskette) also contain example test files, including a typical SEGY file along with the resulting ASCII xyz and postscript files. Requirements for compiling the source code into an executable are a C++ compiler. The program has been successfully compiled using Gnu's g++ version 2.8.1, and use of other compilers may require modifications to the existing source code. The g++ compiler is a free, high quality C++ compiler and may be downloaded from the ftp site: ftp://ftp.gnu.org/gnu Requirements for plotting the seismic data is the existence of the GMT plotting package. The GMT plotting package may be downloaded from the web site: http://www.soest.hawaii.edu/gmt/

Study of beam transverse properties of a thermionic electron gun for application to a compact THz free electron laser

International Nuclear Information System (INIS)

Hu, Tongning; Qin, Bin; Tan, Ping; Chen, Qushan; Yang, Lei; Pei, Yuanji; Li, Ji

2014-01-01

A novel thermionic electron gun adopted for use in a high power THz free electron laser (FEL) is proposed in this paper. By optimization of the structural and radiofrequency (RF) parameters, the physical design of the gun is performed using dynamic calculations. Velocity bunching is used to minimize the bunch's energy spread, and the dynamic calculation results indicate that high quality beams can be provided. The transverse properties of the beams generated by the gun are also analyzed. The novel RF focusing effects of the resonance cavity are investigated precisely and are used to establish emittance compensation, which enables the injector length to be reduced. In addition, the causes of the extrema of the beam radius and the normalized transverse emittance are analyzed and interpreted, respectively, and slice simulations are performed to illustrate how the RF focusing varies along the bunch length and to determine the effects of that variation on the emittance compensation. Finally, by observation of the variations of the beam properties in the drift tube behind the electron gun, prospective assembly scenarios for the complete THz-FEL injector are discussed, and a joint-debugging process for the injector is implemented

Conversion Preliminary Safety Analysis Report for the NIST Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Diamond, D. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Baek, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hanson, A. L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, L-Y [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cuadra, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-01-30

The NIST Center for Neutron Research (NCNR) is a reactor-laboratory complex providing the National Institute of Standards and Technology (NIST) and the nation with a world-class facility for the performance of neutron-based research. The heart of this facility is the NIST research reactor (aka NBSR); a heavy water moderated and cooled reactor operating at 20 MW. It is fueled with high-enriched uranium (HEU) fuel elements. A Global Threat Reduction Initiative (GTRI) program is underway to convert the reactor to low-enriched uranium (LEU) fuel. This program includes the qualification of the proposed fuel, uranium and molybdenum alloy foil clad in an aluminum alloy, and the development of the fabrication techniques. This report is a preliminary version of the Safety Analysis Report (SAR) that would be submitted to the U.S. Nuclear Regulatory Commission (NRC) for approval prior to conversion. The report follows the recommended format and content from the NRC codified in NUREG-1537, “Guidelines for Preparing and Reviewing Applications for the Licensing of Non-power Reactors,” Chapter 18, “Highly Enriched to Low-Enriched Uranium Conversions.” The emphasis in any conversion SAR is to explain the differences between the LEU and HEU cores and to show the acceptability of the new design; there is no need to repeat information regarding the current reactor that will not change upon conversion. Hence, as seen in the report, the bulk of the SAR is devoted to Chapter 4, Reactor Description, and Chapter 13, Safety Analysis.

Uranium conversion; Urankonvertering

Energy Technology Data Exchange (ETDEWEB)

Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

2006-03-15

FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

Solar energy conversion: an analysis of impacts on desert ecosystems. Final report, June 1, 1977-December 31, 1977

Energy Technology Data Exchange (ETDEWEB)

Patten, D.C.

1978-05-01

A research program is proposed to determine the response of desert ecosystems to the operation of various solar conversion systems. Existing solar powered irrigation pumping systems are described, as well as the 5 MW solar thermal test system at Albuquerque, the proposed 10 MW central receiver system at Barstow, and photovoltaic solar dispersed power systems. The theoretical ecological impacts of solar conversion system are described. Three major impact categories are discussed in detail: shading, wind deflection, and physical disturbance. Research needs necessary to evaluate biotic and abiotic changes in the desert ecosystem are delineated, and specific monitoring and manipulation programs for existing and proposed solar conversion sites are proposed.

Review of liquid metal heat pipe work at Los Alamos

International Nuclear Information System (INIS)

Reid, R.S.; Merrigan, M.A.; Sena, J.T.

1990-01-01

A survey of space-power related liquid metal heat pipe work at Los Alamos National Laboratory is presented. Heat pipe development at Los Alamos has been on-going since 1963. Heat pipes were initially developed for thermionic nuclear-electrical power production in space. Since then Los Alamos has developed liquid metal heat pipes for numerous applications related to high temperature systems in both the space and terrestrial environments. Some of these applications include thermionic electrical generators, thermoelectric energy conversion (both in-core and direct radiation), thermal energy storage, hypersonic vehicle leading edge cooling, and heat pipe vapor laser cells. Some of the work performed at Los Alamos has been documented in internal reports that are often little-known. A representative description and summary of progress in space-related liquid metal heat pipe technology is provided followed by a reference section citing sources where these works may be found. 53 refs

PLC Programming

International Nuclear Information System (INIS)

Lee, Seong Jae; Wi, Seong Dong; Yoo, Jong Seon; Kim, Se Chan

2001-02-01

This book tells of PLC programming for KGL-WIN with summary of PLC, performance and function of PLC like characteristic of KGL-WIN, connection method with PLC, basic performance of K200S/K300S/K1000S, diagram of input and output H/W, writing project, staring the program, editing of program, on-line function, debugging and instructions like control, timer and counter, data transmission, comparison, rotation and moving, system, data operating data conversion and application program.

Computer program for diagnostic X-ray exposure conversion

International Nuclear Information System (INIS)

Lewis, S.L.

1984-01-01

Presented is a computer program designed to convert any given set of diagnostic X-ray exposure factors sequentially into another, yielding either an equivalent photographic density or one increased or decreased by a specifiable proportion. In addition to containing the wherewithal with which to manipulate a set of exposure factors, the facility to print hard (paper) copy is included enabling the results to be pasted into a notebook and used at any time. This program was originally written as an investigative exercise into examining the potential use of computers for practical radiographic purposes as conventionally encountered. At the same time, its possible use as an educational tool was borne in mind. To these ends, the current version of this program may be used as a means whereby exposure factors used in a diagnostic department may be altered to suit a particular requirement or may be used in the school as a mathematical model to describe the behaviour of exposure factors under manipulation without patient exposure. (author)

Nitric oxide-to-nitrogen dioxide conversion rates at a natural gas compressor station

International Nuclear Information System (INIS)

Gibbons, T.H.; Gebhart, D.H.

1992-01-01

An ambient air quality measurements program collected NO x data for a year at a natural gas compressor station located in the southwestern United States. This monitoring program had the unique characteristic of measuring ambient NO x concentrations at a remote location that was virtually free of NO sources other than the compressor station. These measurements indicate that the only source of NO x emissions in the area comes from the combustion of natural gas by the compressor station turbines. Thus, increases in NO 2 calculation of NO-to-NO 2 conversion rates. These results indicate 22 percent of the compressor station NO x emissions were converted to NO 2 in the near field. Regulatory modeling methods often assume that all NO x emissions exist as NO 2 . In an environment where ozone concentrations are relatively low, however, NO 2 concentrations are commonly calculated using the ozone limiting method (OLM), wherein NO conversion to NO 2 is limited by the amount of ozone present. Results from the measurement program show that the OLM generally overpredicts NO 2 concentrations in the near field. A partial conversion method is more suitable for predicting NO 2 concentrations for low-level natural gas combustion sources

Calculational models of close-spaced thermionic converters

International Nuclear Information System (INIS)

McVey, J.B.

1983-01-01

Two new calculational models have been developed in conjunction with the SAVTEC experimental program. These models have been used to analyze data from experimental close-spaced converters, providing values for spacing, electrode work functions, and converter efficiency. They have also been used to make performance predictions for such converters over a wide range of conditions. Both models are intended for use in the collisionless (Knudsen) regime. They differ from each other in that the simpler one uses a Langmuir-type formulation which only considers electrons emitted from the emitter. This approach is implemented in the LVD (Langmuir Vacuum Diode) computer program, which has the virtue of being both simple and fast. The more complex model also includes both Saha-Langmuir emission of positive cesium ions from the emitter and collector back emission. Computer implementation is by the KMD1 (Knudsen Mode Diode) program. The KMD1 model derives the particle distribution functions from the Vlasov equation. From these the particle densities are found for various interelectrode motive shapes. Substituting the particle densities into Poisson's equation gives a second order differential equation for potential. This equation can be integrated once analytically. The second integration, which gives the interelectrode motive, is performed numerically by the KMD1 program. This is complicated by the fact that the integrand is often singular at one end point of the integration interval. The program performs a transformation on the integrand to make it finite over the entire interval. Once the motive has been computed, the output voltage, current density, power density, and efficiency are found. The program is presently unable to operate when the ion richness ratio β is between about .8 and 1.0, due to the occurrence of oscillatory motives

Biomass Feedstock and Conversion Supply System Design and Analysis

Energy Technology Data Exchange (ETDEWEB)

Jacobson, Jacob J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Roni, Mohammad S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cafferty, Kara G. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-09-01

Idaho National Laboratory (INL) supports the U.S. Department of Energy’s bioenergy research program. As part of the research program INL investigates the feedstock logistics economics and sustainability of these fuels. A series of reports were published between 2000 and 2013 to demonstrate the feedstock logistics cost. Those reports were tailored to specific feedstock and conversion process. Although those reports are different in terms of conversion, some of the process in the feedstock logistic are same for each conversion process. As a result, each report has similar information. A single report can be designed that could bring all commonality occurred in the feedstock logistics process while discussing the feedstock logistics cost for different conversion process. Therefore, this report is designed in such a way that it can capture different feedstock logistics cost while eliminating the need of writing a conversion specific design report. Previous work established the current costs based on conventional equipment and processes. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $55/dry ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, low-cost feedstock. The 2017 programmatic target is to supply feedstock to the conversion facility that meets the in-feed conversion process quality specifications at a total logistics cost of $80/dry T. The $80/dry T. target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all conversion in-feed quality targets

Competition preparation guideline in undergraduate program of information system school of Industrial Engineering Telkom University based on knowledge conversion

Science.gov (United States)

Darmawan, F. R.; Soesanto, R. P.; Kurniawati, A.; Kurniawan, M. T.

2017-12-01

The role of higher education in the development of science and technology is not only from the contribution of the high-quality alumni but also from the research and relevant competition with the needs of development in such a country. In a competition, the student can improve their soft skill and academic skill such as analytical and critical thinking, communication skills and mental. The number of relevant competition by students is also included in accreditation clause, therefore student involvement in competition is seen as important for the undergraduate program in University. The most problem in university is the high turnover from the student. Bachelor program in Indonesia usually takes 4 years to complete, and the high turnover causes the student come and go as they are a graduate from the institution without preserving the knowledge and experience from the competition to other students. This research aims to develop a guidance for competition preparation in the university by using knowledge conversion. The object of this research is an information system undergraduate program in the school of industrial engineering Telkom University. The best practice selection is done by using factor rating method. Delphi method is used to identify the criteria, and AHP method is used to calculate the weight of each criterion. From the factor rating result it is known that from 3 respondent, best practice from respondent A (7.321) is used for preparing the programming competition in an undergraduate program of information system in the school of industrial engineering Telkom University. FGD is done to disseminate the selected best practice into the process stakeholder which is head of the student affair of the school of industrial engineering, students, and laboratory assistants. Future research can be done to create more comprehensive criteria for selecting the best practice.

Online Scholarly Conversations in General Education Astronomy Courses

Science.gov (United States)

Cai, Qijie; Wong, Ka-Wah

2018-01-01

In general education astronomy courses, many students are struggling with understanding the foundational concepts and theories in astronomy. One of the possible reasons is that, due the large class size, many of the courses are taught using a lecture mode, where human interactions and active learning are limited (Freeman et al., 2014). To address this challenge, we have applied the knowledge building framework (Scardamalia & Bereiter, 2006) to design an online collaborative learning component, called Scholarly Conversations, to be integrated into a general education astronomy course at a public, comprehensive university.During Scholarly Conversations, students are treated as scholars to advance knowledge frontiers (Scardamalia & Bereiter, 2006). The whole process involves the creation of new ideas and requires discourse and collective work for the advancement and creation of artifacts, such as theories and models (van Aalst, 2009). Based on the knowledge building principles (Scardamalia, 2002; Zhang, Scardamalia, Reeve, & Messina, 2009), several features have been built into Scholarly Conversations so that students are guided to deepen understanding of the astronomy concepts through three phases: knowledge sharing, knowledge construction and knowledge building, and reflections on learning growth (van Aalst, 2009; Cai, 2017). The online Scholarly Conversation is an extension of the lecture component of the general education astronomy course. It promotes student interactions and collaborative learning, and provides scaffolds for students to construct meanings of the essential concepts in astronomy through social learning and online technology. In this presentation, we will explain the specific design principles of the online Scholarly Conversation, and share the artifacts created to facilitate the online conversations in an general education astronomy course.Note: This project has been supported by the College of Education Research Grant Program at Minnesota State

A Review of Previous Research in Direct Energy Conversion Fission Reactors

International Nuclear Information System (INIS)

DUONG, HENRY; POLANSKY, GARY F.; SANDERS, THOMAS L.; SIEGEL, MALCOLM D.

1999-01-01

From the earliest days of power reactor development, direct energy conversion was an obvious choice to produce high efficiency electric power generation. Directly capturing the energy of the fission fragments produced during nuclear fission avoids the intermediate conversion to thermal energy and the efficiency limitations of classical thermodynamics. Efficiencies of more than 80% are possible, independent of operational temperature. Direct energy conversion fission reactors would possess a number of unique characteristics that would make them very attractive for commercial power generation. These reactors would be modular in design with integral power conversion and operate at low pressures and temperatures. They would operate at high efficiency and produce power well suited for long distance transmission. They would feature large safety margins and passively safe design. Ideally suited to production by advanced manufacturing techniques, direct energy conversion fission reactors could be produced more economically than conventional reactor designs. The history of direct energy conversion can be considered as dating back to 1913 when Moseleyl demonstrated that charged particle emission could be used to buildup a voltage. Soon after the successful operation of a nuclear reactor, E.P. Wigner suggested the use of fission fragments for direct energy conversion. Over a decade after Wigner's suggestion, the first theoretical treatment of the conversion of fission fragment kinetic energy into electrical potential appeared in the literature. Over the ten years that followed, a number of researchers investigated various aspects of fission fragment direct energy conversion. Experiments were performed that validated the basic physics of the concept, but a variety of technical challenges limited the efficiencies that were achieved. Most research in direct energy conversion ceased in the US by the late 1960s. Sporadic interest in the concept appears in the literature until this

Computers and conversation

CERN Document Server

Luff, Paul; Gilbert, Nigel G

1986-01-01

In the past few years a branch of sociology, conversation analysis, has begun to have a significant impact on the design of human*b1computer interaction (HCI). The investigation of human*b1human dialogue has emerged as a fruitful foundation for interactive system design.****This book includes eleven original chapters by leading researchers who are applying conversation analysis to HCI. The fundamentals of conversation analysis are outlined, a number of systems are described, and a critical view of their value for HCI is offered.****Computers and Conversation will be of interest to all concerne

Preparation results for lifetime test of conversion LEU fuel in plutonium production reactors

International Nuclear Information System (INIS)

Vatulin, A.; Stetskiy, Yu.; Kukharkin, N.; Kalougin, A.; Gavrilov, P.; Ivanov, A.

1999-01-01

The program of converting Russian production reactors for the purpose to stop their plutonium fabrication is currently in progress. The program also provides for operation of these reactors under the conversion mode with using of low-enriched fuel (LEU). LEU fuel elements were developed and activities related to their preparation for reactor tests were carried out. (author)

Energy production, conversion, storage, conservation, and coupling

CERN Document Server

Demirel, Yaşar

2012-01-01

Understanding the sustainable use of energy in various processes is an integral part of engineering and scientific studies, which rely on a sound knowledge of energy systems. Whilst many institutions now offer degrees in energy-related programs, a comprehensive textbook, which introduces and explains sustainable energy systems and can be used across engineering and scientific fields, has been lacking. Energy: Production, Conversion, Storage, Conservation, and Coupling provides the reader with a practical understanding of these five main topic areas of energy including 130 examples and over 600 practice problems. Each chapter contains a range of supporting figures, tables, thermodynamic diagrams and charts, while the Appendix supplies the reader with all the necessary data including the steam tables. This new textbook presents a clear introduction of basic vocabulary, properties, forms, sources, and balances of energy before advancing to the main topic areas of: • Energy production and conversion in importa...

Status of CEA reactor studies for a 200 kWe turbo electric space power system

International Nuclear Information System (INIS)

Carre, F.; Gervaise, F.; Proust, E.; Schwartz, J.P.; Tilliette, Z.; Vrillon, B.

1986-01-01

The present European ARIANE space program will expand after 1995 in the development of the large ARIANE 5 launch vehicle. Considering, that the range of power needs (50 to 400 kWe) and operation times required for the space missions planned after the year 2000, are relevant to a nuclear power system, the French Centre National d'Etudes Spatiales (CNES) invited in 1983 the Commissariat a l'Energie Atomique (CEA) to undertake preliminary studies on space power systems. The purpose of the present two year phase (mid 1984-mid 1986) is to identify key technologies for a space generator within the power range of interest and to estimate the development cost of such a project to be examined for commitment in 1986. This work mainly consists in the feasibility and cost assessment of a reference 200 kWe turboelectric space generator, selected for the maturity and availability of the conversion system and for its attractive specific mass compared to thermionics and thermoelectricity, considering the available radiator area afforded by the specific ARIANE 5 geometrical features. The system is basically composed of a fast neutron spectrum lithium cooled reactor, of a Brayton conversion loop and of a heat pipe radiator

Natural gas conversion. Part VI

International Nuclear Information System (INIS)

Iglesia, E.; Spivey, J.J.; Fleisch, T.H.

2001-01-01

This volume contains peer-reviewed manuscripts describing the scientific and technological advances presented at the 6th Natural Gas Conversion Symposium held in Alaska in June 2001. This symposium continues the tradition of excellence and the status as the premier technical meeting in this area established by previous meetings. The 6th Natural Gas Conversion Symposium is conducted under the overall direction of the Organizing Committee. The Program Committee was responsible for the review, selection, editing of most of the manuscripts included in this volume. A standing International Advisory Board has ensured the effective long-term planning and the continuity and technical excellence of these meetings. The titles of the contributions are: Impact of syngas generation technology selection on a GTL FPSO; Methane conversion via microwave plasma initiated by a metal initiator; Mechanism of carbon deposit/removal in methane dry reforming on supported metal catalysts; Catalyst-assisted oxidative dehydrogenation of light paraffins in short contact time reactors; Catalytic dehydrogenation of propane over a PtSn/SiO 2 catalyst with oxygen addition: selective oxidation of H2 in the presence of hydrocarbons; Hydroconversion of a mixture of long chain n-paraffins to middle distillate: effect of the operating parameters and products properties; Decomposition/reformation processes and CH4 combustion activity of PdO over Al2O3 supported catalysts for gas turbine applications; Lurgi's mega-methanol technology opens the door for a new era in down-stream applications;Expanding markets for GTL fuels and specialty products; Some critical issues in the analysis of partial oxidation reactions in monolith reactors

An overview of the RECH-1 reactor conversion

International Nuclear Information System (INIS)

Klein, J.; Medel, J.; Daie, J.; Torres, H.

2000-01-01

The RECH-l research reactor achieved the first criticality on October 13, 1974 using HEU MTR type fuel elements, which were fabricated by the UKAEA at Dounreay, Scotland. In 1979, the conversion of the reactor to use LEU fuel was decided; however, a rough estimate of the uranium density needed to convert the reactor gave 3.7 g/cm 3 . This density was not available, and to maintain the overall fuel element geometry it was necessary to convert the reactor to use 45% enriched uranium fuel. In 1985, the conversion of the reactor to use medium enriched uranium was achieved. Some years later, the Chilean Nuclear Energy Commission developed the capability to produce fuel elements based on U 3 Si 2 -Al dispersion fuel. Once the plant and the manufacturing and quality control procedures were commissioned to permit the production of fuel elements, a fabrication program starts to produce LEU fuel elements with a uranium density of 3.4 g/cm 3 . A fabrication qualification period that extended to the required fuel plates for the assembly of two fuel elements started. In November 1998, the first four LEU fuel elements manufactured by the Chilean Fuel Fabrication Plant were delivered to the reactor. When the first two fuel elements were introduced into the core a LEU fuel element qualification program began. While those fuel elements remain in the core, an evaluation program is being applied to observe its performance under irradiation condition. (author)

A design study of reactor core optimization for direct nuclear heat-to-electricity conversion in a space power reactor

Energy Technology Data Exchange (ETDEWEB)

Yoshikawa, Hidekazu; Takahashi, Makoto; Shimoda, Hiroshi; Takeoka, Satoshi [Kyoto Univ. (Japan); Nakagawa, Masayuki; Kugo, Teruhiko

1998-01-01

To propose a new design concept of a nuclear reactor used in the space, research has been conducted on the conceptual design of a new nuclear reactor on the basis of the following three main concepts: (1) Thermionic generation by thermionic fuel elements (TFE), (2) reactivity control by rotary reflector, and (3) reactor cooling by liquid metal. The outcomes of the research are: (1) A calculation algorithm was derived for obtaining convergent conditions by repeating nuclear characteristic calculation and thermal flow characteristic calculation for the space nuclear reactor. (2) Use of this algorithm and the parametric study established that a space nuclear reactor using 97% enriched uranium nitride as the fuel and lithium as the coolant and having a core with a radius of about 25 cm, a height of about 50 cm and a generation efficiency of about 7% can probably be operated continuously for at least more than ten years at 100 kW only by reactivity control by rotary reflector. (3) A new CAD/CAE system was developed to assist design work to optimize the core characteristics of the space nuclear reactor comprehensively. It is composed of the integrated design support system VINDS using virtual reality and the distributed system WINDS to collaboratively support design work using Internet. (N.H.)

Elements of energy conversion

CERN Document Server

Russell, Charles R

2013-01-01

Elements of Energy Conversion brings together scattered information on the subject of energy conversion and presents it in terms of the fundamental thermodynamics that apply to energy conversion by any process. Emphasis is given to the development of the theory of heat engines because these are and will remain most important power sources. Descriptive material is then presented to provide elementary information on all important energy conversion devices. The book contains 10 chapters and opens with a discussion of forms of energy, energy sources and storage, and energy conversion. This is foll

Numerical study of the particle transport in fast neutron detectors with conversion layer

International Nuclear Information System (INIS)

Sedlackova, K.; Zatko, B.; Necas, V.

2012-01-01

This paper deals with fast neutron and recoil proton transport simulation using statistical analysis of Monte Carlo radiation transport code (MCNPX). Its possibilities in the detector design and optimization are presented. MCNPX proved as a very advantageous self-contained simulation program for fast neutron and secondary proton tracking. Simulations of respective particle transport through conversion layer of HDPE and further in the active volume of detector let us to follow important characteristics as neutron/proton flux density, reaction rate of elastic scattering on hydrogen nuclei and deposited energy as well as their dependencies on incident neutron energy and conversion layer/active region thickness. The efficiency of neutrons to protons conversion has been calculated and its maximum was reached for 500 μm thick conversion layer. The minimum active region thickness has been estimated to be about 300 μm.(authors)

Iterated multidimensional wave conversion

International Nuclear Information System (INIS)

Brizard, A. J.; Tracy, E. R.; Johnston, D.; Kaufman, A. N.; Richardson, A. S.; Zobin, N.

2011-01-01

Mode conversion can occur repeatedly in a two-dimensional cavity (e.g., the poloidal cross section of an axisymmetric tokamak). We report on two novel concepts that allow for a complete and global visualization of the ray evolution under iterated conversions. First, iterated conversion is discussed in terms of ray-induced maps from the two-dimensional conversion surface to itself (which can be visualized in terms of three-dimensional rooms). Second, the two-dimensional conversion surface is shown to possess a symplectic structure derived from Dirac constraints associated with the two dispersion surfaces of the interacting waves.

Status of NASA's Advanced Radioisotope Power Conversion Technology Research and Development

Science.gov (United States)

Wong, Wayne A.; Anderson, David J.; Tuttle, Karen L.; Tew, Roy C.

2006-01-01

NASA s Advanced Radioisotope Power Systems (RPS) development program is funding the advancement of next generation power conversion technologies that will enable future missions that have requirements that can not be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power Systems (RPS). Requirements of advanced radioisotope power systems include high efficiency and high specific power (watts/kilogram) in order to meet mission requirements with less radioisotope fuel and lower mass. Other Advanced RPS development goals include long-life, reliability, and scalability so that these systems can meet requirements for a variety of future space applications including continual operation surface missions, outer-planetary missions, and solar probe. This paper provides an update on the Radioisotope Power Conversion Technology Project which awarded ten Phase I contracts for research and development of a variety of power conversion technologies consisting of Brayton, Stirling, thermoelectrics, and thermophotovoltaics. Three of the contracts continue during the current Phase II in the areas of thermoelectric and Stirling power conversion. The accomplishments to date of the contractors, project plans, and status will be summarized.

IRT - Sofia conversion feasibility study experience 2002-2009

Energy Technology Data Exchange (ETDEWEB)

Belousov, S.I.; Apostolov, T.G. [Institute for Nuclear Research and Nuclear Energy of Bulgarian Academy of Science, Tsarigradsko 72, 1784 Sofia (Bulgaria)

2010-07-01

A joint conversion feasibility study concerning the IRT - Sofia research reactor between INRNE and the RERTR Program at ANL was initiated in 2002. The initial steps studies (up to 2006) were mainly focused on neutronics properties significant for reactor application and safety analyses. Thermal hydraulic, accident analyses as well as additional neutronics study required were performed after that (up to 2010). The obtained results show that the IRT-4M LEU fuel assemblies (19.75% {sup 235}U enrichment) are appropriate for IRT-Sofia conversion (IRT-Sofia was initially designed for the IRT-2M HEU fuel assemblies with 36% {sup 235}U enrichment). The results obtained in the frames of the joint study show that the IRT-Sofia operation even with usage of only one pump in the primary circuit meets all safety requirements at power level up to 1000 kW and that safety is maintained for accident transients. Presented results of analyses (neutronics, thermal hydraulic, and accident) and accumulated experience for the IRT-Sofia will be useful for other research reactors where conversion from IRT-2M (HEU) to IRT-4M (LEU) fuel is underway and/or foreseen. (authors)

Documentation Experiences for Jamaican SLOWPOKE-2 Conversion from HEU to LEU

International Nuclear Information System (INIS)

Warner, T.-A.; Dennis, H.; Antoine, J.

2015-01-01

The Jamaican SLOWPOKE–2 (JM–1) is a 20 kW research reactor manufactured by Atomic Energy of Canada Limited and has been operating since March 1984, in the department of the International Centre for Environmental and Nuclear Sciences (ICENS), at the University of the West Indies, Mona Campus in Kingston, Jamaica. The pool type reactor has been primarily used for Neutron Activation Analysis in environmental, agricultural, geochemical, health-related studies and mineral exploration. The University, assisted by the IAEA under the GTRI/RERTR program, is currently in the process of converting from HEU to LEU. Extensive documentation on policies, general requirements, elements of the conversion quality assurance (QA) system and conversion QA administrative procedures is required for the conversion. The core conversion activities are being carried out in accordance with current international standards and regulatory guidelines of the newly established Jamaican Radiation Safety Authority (RSA) with agreement between the RSA and IAEA or DOE related to Nuclear Safety and Control. The documentation structure has taken into consideration nuclear safety and licensing, LEU fuel design and conversion analysis, LEU fuel procurement and fabrication, removal of HEU fuel and reactor maintenance and conversion and commissioning, with the conversion QA manual at the apex of the structure. To a large extent, the documentation format will adhere to that of the IAEA applicable regulatory standards and guidance documents. The major challenge of the conversion activities, it is envisioned, will come from the absence of any previous regulatory framework in Jamaica; however, a timeline for the process, which includes training and equipping of regulators, will guide operation. (author)

Time to sputum conversion in multidrug-resistant tuberculosis patients in Armenia: retrospective cohort study

Directory of Open Access Journals (Sweden)

Arax Hovhannesyan

2012-06-01

Full Text Available OBJECTIVE: To characterize time to sputum conversion among patients with multidrug resistant tuberculosis who were enrolled into second-line tuberculosis treatment program; to identify risk factors for delayed sputum conversion. DESIGN: Retrospective cohort study designed to identify the factors associated with sputum conversion. Survival analysis was performed using Kaplan-Meier estimator to compute estimates for median time to sputum conversion and Cox proportional hazards model to compute hazard ratios (HR. RESULTS: Sputum conversion from positive to negative was observed in 134 out of 195 cases (69%. Among these who converted the median time to conversion was 3.7 months. Factors independently associated with time to sputum conversion in the proportional hazards model were: male sex (HR=0.51, 95% CI 0.32-0.81, ofloxacin-resistant tuberculosis (HR = 0.45, 95% CI 0.26-0.78 and first period of recruitment into second-line treatment (HR= 0.69, 95% CI 0.47-1.01. CONCLUSION: Time to sputum conversion in patients with multidrug-resistant tuberculosis in Armenia was 5.8 months (range 0.5-17.0 months. High level of ofloxacin resistance was the main reason for compromised response to treatment. Patients with a poor resistance profile and males should be targeted with more aggressive initial therapy.

Time to sputum conversion in multidrug-resistant tuberculosis patients in Armenia: retrospective cohort study

Directory of Open Access Journals (Sweden)

Arax Hovhannesyan

2012-01-01

Full Text Available OBJECTIVE: To characterize time to sputum conversion among patients with multidrug resistant tuberculosis who were enrolled into second-line tuberculosis treatment program; to identify risk factors for delayed sputum conversion. DESIGN: Retrospective cohort study designed to identify the factors associated with sputum conversion. Survival analysis was performed using Kaplan-Meier estimator to compute estimates for median time to sputum conversion and Cox proportional hazards model to compute hazard ratios (HR. RESULTS: Sputum conversion from positive to negative was observed in 134 out of 195 cases (69%. Among these who converted the median time to conversion was 3.7 months. Factors independently associated with time to sputum conversion in the proportional hazards model were: male sex (HR=0.51, 95% CI 0.32-0.81, ofloxacin-resistant tuberculosis (HR = 0.45, 95% CI 0.26-0.78 and first period of recruitment into second-line treatment (HR= 0.69, 95% CI 0.47-1.01. CONCLUSION: Time to sputum conversion in patients with multidrug-resistant tuberculosis in Armenia was 5.8 months (range 0.5- 17.0 months. High level of ofloxacin resistance was the main reason for compromised response to treatment. Patients with a poor resistance profile and males should be targeted with more aggressive initial therapy.

Alternative Payment Models Should Risk-Adjust for Conversion Total Hip Arthroplasty: A Propensity Score-Matched Study.

Science.gov (United States)

McLawhorn, Alexander S; Schairer, William W; Schwarzkopf, Ran; Halsey, David A; Iorio, Richard; Padgett, Douglas E

2017-12-06

For Medicare beneficiaries, hospital reimbursement for nonrevision hip arthroplasty is anchored to either diagnosis-related group code 469 or 470. Under alternative payment models, reimbursement for care episodes is not further risk-adjusted. This study's purpose was to compare outcomes of primary total hip arthroplasty (THA) vs conversion THA to explore the rationale for risk adjustment for conversion procedures. All primary and conversion THAs from 2007 to 2014, excluding acute hip fractures and cancer patients, were identified in the National Surgical Quality Improvement Program database. Conversion and primary THA patients were matched 1:1 using propensity scores, based on preoperative covariates. Multivariable logistic regressions evaluated associations between conversion THA and 30-day outcomes. A total of 2018 conversions were matched to 2018 primaries. There were no differences in preoperative covariates. Conversions had longer operative times (148 vs 95 minutes, P reimbursement models shift toward bundled payment paradigms, conversion THA appears to be a procedure for which risk adjustment is appropriate. Copyright © 2017 Elsevier Inc. All rights reserved.

Core conversion anaylses for the Portuguese Research Reactor

International Nuclear Information System (INIS)

Matos, J.E.; Stevens, J.G.; Feldman, E.E.; Stillman, J.A.; Dunn, F.E.; Kalimullah, K.; Marques, J.G.; Barradas, N.P.; Ramos, A.R.; Kling, A.

2006-01-01

Design and safety analyses are presented for conversion of the Portuguese Research Reactor (RPI) from the use of HEU fuel to the use of LEU fuel. The analyses were performed jointly by the RERTR Program at the Argonne National Laboratory (ANL) and the Instituto Tecnologico e Nuclear (ITN). The LEU fuel assembly design uses U 3 Si 2 -Al dispersion fuel with 4.8 g U/cm 3 and is very similar to the HEU fuel design. The results of neutronic studies, steady-state thermal-hydraulic analyses, accident analyses, and revisions to the Operating Limits and Conditions demonstrate that the RPI reactor can be operated safely with the new LEU fuel assemblies. Delivery of the LEU fuel is expected around the end of 2006, with conversion in early 2007. The HEU fuel is planned to be returned to the US in 2008.

Biomass energy systems program summary

Energy Technology Data Exchange (ETDEWEB)

None

1980-07-01

Research programs in biomass which were funded by the US DOE during fiscal year 1978 are listed in this program summary. The conversion technologies and their applications have been grouped into program elements according to the time frame in which they are expected to enter the commercial market. (DMC)

Infrared up-conversion microscope

DEFF Research Database (Denmark)

2014-01-01

There is presented an up-conversion infrared microscope (110) arranged for imaging an associated object (130), wherein the up-conversion infrared microscope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein an objective optical...

Infrared up-conversion telescope

DEFF Research Database (Denmark)

2014-01-01

There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...

Conversion of Semipalatinsk test site

International Nuclear Information System (INIS)

Cherepnin, Yu. S.

1997-01-01

The conversion of the former defense enterprises of STS (Semipalatinsk Test Sate) started under very difficult conditions, when not only research and production activity, but all social life of Kurchatov city were conversed which was caused by a fast curtailment and restationing of Russian military units from the test site. A real risk of a complete destruction of the whole research and production structure of the city existed. From this point of view, the decision of the Republic of Kazakhstan Government to create the National Nuclear Center on the base of the test site research enterprises was actual and timely. During 1993, three research institutes of NNC RK - Institute of Atomic Energy, Institute of Geophysics Research and Institute of Radiation Safety and Environment were established. This decision, under conditions of the Ussr disintegration and liquidation of the test site military divisions, allowed to preserve the qualified personnel, to provide and follow-up the operation of nuclear dangerous facilities, to develop and start the realization of the full scale conversion program.At present time, directions and structure of basic research work in NNC RK are as follows: - liquidation of nuclear explosions consequences; - liquidation of technological infrastructure used for preparation and conduction of nuclear weapon testing; - creation of technology, equipment and places for acceptance and storage of radioactive wastes; - working out of atomic energy development conception in Kazakhstan; - study of reactor core melt behavior under severe accidents in NPP; - development of methods and means of nuclear testing detection, continuous monitoring of nuclear explosions; - experimental work on a study of structure materials behavior of ITER thermonuclear reactor; - creation of industries requiring a lage implementation of science

A Model for Conversation

DEFF Research Database (Denmark)

Ayres, Phil

2012-01-01

This essay discusses models. It examines what models are, the roles models perform and suggests various intentions that underlie their construction and use. It discusses how models act as a conversational partner, and how they support various forms of conversation within the conversational activity...

Design study of eventual core conversion for the research reactor RA

International Nuclear Information System (INIS)

Matausek, M. V.; Marinkovic, N.

1998-01-01

Main options are specified for the future status of the 6.5 MW heavy water research reactor RA. Arguments pro and contra restarting the reactor are presented. When considering the option to restart the RA reactor, possibilities to improve its neutronic parameters, such as neutron flux values and irradiation capabilities are discussed, as well as the compliance with the worldwide activities of Reduced Enrichment for Research and Test Reactors (RERTR) program. Possibility of core conversion is examined. Detailed reactor physics design calculations are performed for different fuel types and uranium loading. For different fuel management schemes results are presented for the effective, multiplication factor, power distribution, fuel burnup and consumption. It is shown that, as far as reactor core parameters are considered, conversion to lower enrichment fuel could be easily accomplished. However, conversion to the lower enrichment could only be justified if combined with improvement of some other reactor attributes. (author)

5 CFR 890.401 - Temporary extension of coverage and conversion.

Science.gov (United States)

2010-01-01

... exercise the right of conversion provided for by this part. The 31-day extension of coverage and the right... benefits with respect to that person while he or she is entitled to any inpatient benefits under the prior... Program contract on the day after the day all inpatient benefits have been exhausted under the prior plan...

Program THEK energy production units of average power and using thermal conversion of solar radiation

Science.gov (United States)

1978-01-01

General studies undertaken by the C.N.R.S. in the field of solar power plants have generated the problem of building energy production units in the medium range of electrical power, in the order of 100 kW. Among the possible solutions, the principle of the use of distributed heliothermal converters has been selected as being, with the current status of things, the most advantageous solution. This principle consists of obtaining the conversion of concentrated radiation into heat by using a series of heliothermal conversion modules scattered over the ground; the produced heat is collected by a heat-carrying fluid circulating inside a thermal loop leading to a device for both regulation and storage.

Four questions and a conversation: Can theory enrich conversation partner training?

DEFF Research Database (Denmark)

Pound, Carole; Ahlsén, Elisabeth; Simmons-Mackie, NIna

Background and aimsConversation partner training (CPT) is an umbrella term for different approaches to intervention aiming to facilitate and improve communication between people with aphasia (PWA) and their conversation partners (CP). Some approaches are grounded in a bottom-up approach...... and interactions. Philosophically informed by existential-phenomenological perspectives, the humanisation framework encourages reflection on what practices can make people feel more (or less) human. Reviewing experiences of conversation against the eight suggested dimensions of what it means to be human may offer...

Direct Conversion of Energy.

Science.gov (United States)

Corliss, William R.

This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Direct energy conversion involves energy transformation without moving parts. The concepts of direct and dynamic energy conversion plus the laws governing energy conversion are investigated. Among the topics…

Conversion coefficients for determining organ doses in paediatric spine radiography

Energy Technology Data Exchange (ETDEWEB)

Seidenbusch, Michael; Schneider, Karl [Ludwig-Maximilians-University of Munich, Institute of Clinical Radiology - Paediatric Radiology, Muenchen (Germany)

2014-04-15

Knowledge of organ and effective doses achieved during paediatric x-ray examinations is an important prerequisite for assessment of radiation burden to the patient. Conversion coefficients for reconstruction of organ and effective doses from entrance doses for segmental spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients are provided regarding the Guidelines of Good Radiographic Technique of the European Commission. Using the personal computer program PCXMC developed by the Finnish Centre for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional segmental spine radiographs were calculated performing Monte Carlo simulations in mathematical hermaphrodite phantom models describing patients of different ages. The clinical variation of beam collimation was taken into consideration by defining optimal and suboptimal radiation field settings. Conversion coefficients for the reconstruction of organ doses in about 40 organs and tissues from measured entrance doses during cervical, thoracic and lumbar spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients were calculated for the standard sagittal and lateral beam projections and the standard focus detector distance of 115 cm. The conversion coefficients presented may be used for organ dose assessments from entrance doses measured during spine radiographs of patients of all age groups and all field settings within the optimal and suboptimal standard field settings. (orig.)

The total flow concept for geothermal energy conversion

Science.gov (United States)

Austin, A. L.

1974-01-01

A geothermal development project has been initiated at the Lawrence Livermore Laboratory (LLL) to emphasize development of methods for recovery and conversion of the energy in geothermal deposits of hot brines. Temperatures of these waters vary from 150 C to more than 300 C with dissolved solids content ranging from less than 0.1% to over 25% by weight. Of particular interest are the deposits of high-temperature/high-salinity brines, as well as less saline brines, known to occur in the Salton Trough of California. Development of this resource will depend on resolution of the technical problems of brine handling, scale and precipitation control, and corrosion/erosion resistant systems for efficient conversion of thermal to electrical energy. Research experience to date has shown these problems to be severe. Hence, the LLL program emphasizes development of an entirely different approach called the Total Flow concept.

Energy conversion statics

CERN Document Server

Messerle, H K; Declaris, Nicholas

2013-01-01

Energy Conversion Statics deals with equilibrium situations and processes linking equilibrium states. A development of the basic theory of energy conversion statics and its applications is presented. In the applications the emphasis is on processes involving electrical energy. The text commences by introducing the general concept of energy with a survey of primary and secondary energy forms, their availability, and use. The second chapter presents the basic laws of energy conversion. Four postulates defining the overall range of applicability of the general theory are set out, demonstrating th

Uranium Conversion & Enrichment

Energy Technology Data Exchange (ETDEWEB)

Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-02-06

The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U₃O₈ yellowcake into UF₆. Conversion and enrichment of uranium is usually required to obtain material with enough ²³⁵U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

Freely flowing conversations

DEFF Research Database (Denmark)

Aakjær, Marie Kirstejn; Andrade, David; Dexters, Peter

and in regards to rehabilitation efforts. In the context of prisons UDI is inspired by the complexity approach (Stacey 2005). We seek to facilitate freely flowing conversations between inmates, staff and managers – pushing the boundaries of existing norms, roles and beliefs. In the end however we rely...... relations by changing conversations. Through the theoretical framework of the complexity approach, we discuss how this may lead to organizational change. Finally we suggest that inviting inmates to take part in conversations about core organizational development may be a fundamental strategy in trying...

Political conversations on Facebook

DEFF Research Database (Denmark)

Sørensen, Mads P.

2016-01-01

Political conversations are according to theories on deliberative democracy essential to well-functioning democracies. Traditionally these conversations have taken place in face-to-face settings, in e.g. party meetings and town meetings. However, social media such as Facebook and Twitter offers new...... possibilities for online political conversations between citizens and politicians. This paper examines the presence on Facebook and Twitter of Members of the Danish national Parliament, the Folketing, and focusses on a quantitative mapping of the political conversation activities taking place in the threads...... following Facebook posts from Danish Members of Parliament (MPs). The paper shows that, in comparison with previous findings from other countries, Danish MPs have a relatively high degree of engagement in political conversations with citizens on Facebook – and that a large number of citizens follow MPs...

[Conversation analysis for improving nursing communication].

Science.gov (United States)

Yi, Myungsun

2007-08-01

Nursing communication has become more important than ever before because quality of nursing services largely depends on the quality of communication in a very competitive health care environment. This article was to introduce ways to improve nursing communication using conversation analysis. This was a review study on conversation analysis, critically examining previous studies in nursing communication and interpersonal relationships. This study provided theoretical backgrounds and basic assumptions of conversation analysis which was influenced by ethnomethodology, phenomenology, and sociolinguistic. In addition, the characteristics and analysis methods of conversation analysis were illustrated in detail. Lastly, how conversation analysis could help improve communication was shown, by examining researches using conversation analysis not only for ordinary conversations but also for extraordinary or difficult conversations such as conversations between patients with dementia and their professional nurses. Conversation analysis can help in improving nursing communication by providing various structures and patterns as well as prototypes of conversation, and by suggesting specific problems and problem-solving strategies in communication.

ACCULIB, Program Library of Mathematical Routines

International Nuclear Information System (INIS)

Van Kats, J.M.; Rusman, C.J.; Van der Vorst, H.A.

1987-01-01

Description of program or function - ACCULIB is a collection of programs and subprograms for: - approximation and interpolation problems; - the evaluation of series of orthogonal polynomials; - evaluation of the complementary error function; - sorting problems and permutations; - differential equation problems; - linear algebra eigenvalue problems; - optimization problems; - fast Fourier transformations and Fourier series; - numerical quadrature of continuous functions; - linear systems and other linear algebra problems; - bit manipulation and character handling/transmission; - systems of nonlinear equations, in particular the determination of zeros of polynomials; - solution of over-complete systems; - plotting routines for contouring and surface representation; - statistical investigation of data. In addition, many utilities such as code conversion, microfiche production, disk file surveys, layout improvements for ALGOL60 and FORTRAN programs, and the conversion of IBM FORTRAN programs to CDC FORTRAN are included in the collection

Safety aspects of the RECH-1 core conversion

International Nuclear Information System (INIS)

Wetherby, Jaime Riesle

1998-01-01

When the RECH-1 research reactor joined the core conversion program for low enrichment fuel, the need to review some safety related aspects, which are currently under way with different degrees of progress, became apparent. The mentioned aspects can be grouped into: evaluation of the technical specifications of the new fuel elements: the technical specifications were carefully verified and contrasted with the recommendations of the IAEA and with those of manufacturers which are widely known for their expertise. (author)

Seismic analysis, support design and stress calculation of HTR-PM transport and conversion devices

International Nuclear Information System (INIS)

Zhang Zheyu; Yuan Chaolong; Zhang Haiquan; Nie Junfeng

2012-01-01

Background: The transport and conversion devices are important guarantees for normal operation of HTR-PM fuel handling system in normal and fault conditions. Purpose: A conflict of devices' support design needs to be solved. The flexibility of supports is required because of pipe thermal expansion displacement, while the stiffness is also required because of large devices quality and eccentric distance. Methods: In this paper, the numerical simulation was employed to analyze the seismic characteristics and optimize the support program, Under the chosen support program, the stress calculation of platen support bracket was designed by solidworks software. Results: The supports solved the conflict between the flexibility and stiffness requirements. Conclusions: Therefore, it can ensure the safety of transport and conversion devices and the supports in seismic conditions. (authors)

Proceedings of the symposium on assessing the industrial hygiene monitoring needs for the coal conversion and oil shale industries

Energy Technology Data Exchange (ETDEWEB)

White, O. Jr. (ed.)

1979-03-01

This work was supported by the United States Department of Energy, Division of Biomedical and Environmental Research, Analysis and Assessment Program, through the Safety and Environmental Protection Division at Brookhaven National Laboratory. The symposium program included presentations centering around the themes: Recognition of Occupational Health Monitoring Requirements for the Coal Conversion and Oil Shale Industries and Status of Dosimetry Technology for Occupational Health Monitoring for the Coal Conversion and Oil Shale Industries. Sixteen papers have been entered individually into EDB and ERA; six had been entered previously from other sources. (LTN)

Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels Conversion Pathway: Fast Pyrolysis and Hydrotreating Bio-Oil Pathway "The 2017 Design Case"

Energy Technology Data Exchange (ETDEWEB)

Kevin L. Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J. Bonner; Garold L. Gresham; J. Richard Hess; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

2014-01-01

The U.S. Department of Energy promotes the production of liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass sustainable supply, logistics, conversion, and overall system sustainability. As part of its involvement in this program, Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL quantified and the economics and sustainability of moving biomass from the field or stand to the throat of the conversion process using conventional equipment and processes. All previous work to 2012 was designed to improve the efficiency and decrease costs under conventional supply systems. The 2012 programmatic target was to demonstrate a biomass logistics cost of $55/dry Ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model.

Postoperative conversion disorder.

Science.gov (United States)

Afolabi, Kola; Ali, Sameer; Gahtan, Vivian; Gorji, Reza; Li, Fenghua; Nussmeier, Nancy A

2016-05-01

Conversion disorder is a psychiatric disorder in which psychological stress causes neurologic deficits. A 28-year-old female surgical patient had uneventful general anesthesia and emergence but developed conversion disorder 1 hour postoperatively. She reported difficulty speaking, right-hand numbness and weakness, and right-leg paralysis. Neurologic examination and imaging revealed no neuronal damage, herniation, hemorrhage, or stroke. The patient mentioned failing examinations the day before surgery and discontinuing her prescribed antidepressant medication, leading us to diagnose conversion disorder, with eventual confirmation by neuroimaging and follow-up examinations. Copyright © 2016 Elsevier Inc. All rights reserved.

Uranium conversion wastes

International Nuclear Information System (INIS)

Vicente, R.; Dellamano, J.C.

1989-12-01

A set of mathematical equations was developed and used to estimate the radiological significance of each radionuclide potentially present in the uranium refining industry effluents. The equations described the evolution in time of the radionuclides activities in the uranium fuel cycle, from mining and milling, through the yellowcake, till the conversion effluents. Some radionuclides that are not usually monitored in conversion effluents (e.g. Pa-231 and Ac-227) were found to be potentially relevant from the radiological point of view in conversion facilities, and are certainly relevant in mining and milling industry, at least in a few waste streams. (author) [pt

5 CFR 317.302 - Conversion procedures.

Science.gov (United States)

2010-01-01

... conversion. (2) Pay. Upon conversion to the Senior Executive Service, an employee's SES rate will be... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Conversion procedures. 317.302 Section... IN THE SENIOR EXECUTIVE SERVICE Conversion to the Senior Executive Service § 317.302 Conversion...

Development of a conversational text editor on MITRA 125 used with a TEKTRONIX 4014 display console

International Nuclear Information System (INIS)

Siffre, Evelyne.

1980-06-01

The purpose of this study, which falls within the purview of a nuclear physics research laboratory, is the development of a simple to use conversational text editor to mitigate the defects of the MMT2 monitor. The operations to be executed are: - creation of a source file written in FORTRAN - concatenation of the various stages to obtain a workable program: FORTRAN compilation, edition of links, group generation; - execution of this program. These operations are performed in two different ways: 1) by using the system controls as from the teleprinter (this corresponds to the previous use). The sequence of controls to be effected is described; 2) by using the EDI 125 conversational editor [fr

An Algebra for Program Fragments

DEFF Research Database (Denmark)

Kristensen, Bent Bruun; Madsen, Ole Lehrmann; Møller-Pedersen, Birger

1985-01-01

Program fragments are described either by strings in the concrete syntax or by constructor applications in the abstract syntax. By defining conversions between these forms, both may be intermixed. Program fragments are constructed by terminal and nonterminal symbols from the grammar and by variab...

Chronology of a Successful Conversion--Contractor Revives School Lunch Program.

Science.gov (United States)

Johnston, James B.

1994-01-01

A New York State school district employed a management company to privatize the food-service program with the goal of enticing all students to eat lunch. Expertise in marketing, menu planning, and food-service operation turned the program around. Suggests questions to ask when selecting a management company. (MLF)

Conversational flow promotes solidarity.

Science.gov (United States)

Koudenburg, Namkje; Postmes, Tom; Gordijn, Ernestine H

2013-01-01

Social interaction is fundamental to the development of various aspects of "we-ness". Previous research has focused on the role the content of interaction plays in establishing feelings of unity, belongingness and shared reality (a cluster of variables referred to as solidarity here). The present paper is less concerned with content, but focuses on the form of social interaction. We propose that the degree to which conversations flow smoothly or not is, of itself, a cue to solidarity. We test this hypothesis in samples of unacquainted and acquainted dyads who communicate via headsets. Conversational flow is disrupted by introducing a delay in the auditory feedback (vs. no delay). Results of three studies show that smoothly coordinated conversations (compared with disrupted conversations and a control condition) increase feelings of belonging and perceptions of group entitativity, independently of conversation content. These effects are driven by the subjective experience of conversational flow. Our data suggest that this process occurs largely beyond individuals' control. We conclude that the form of social interaction is a powerful cue for inferring group solidarity. Implications for the impact of modern communication technology on developing a shared social identity are discussed.

Conversational flow promotes solidarity.

Directory of Open Access Journals (Sweden)

Namkje Koudenburg

Full Text Available Social interaction is fundamental to the development of various aspects of "we-ness". Previous research has focused on the role the content of interaction plays in establishing feelings of unity, belongingness and shared reality (a cluster of variables referred to as solidarity here. The present paper is less concerned with content, but focuses on the form of social interaction. We propose that the degree to which conversations flow smoothly or not is, of itself, a cue to solidarity. We test this hypothesis in samples of unacquainted and acquainted dyads who communicate via headsets. Conversational flow is disrupted by introducing a delay in the auditory feedback (vs. no delay. Results of three studies show that smoothly coordinated conversations (compared with disrupted conversations and a control condition increase feelings of belonging and perceptions of group entitativity, independently of conversation content. These effects are driven by the subjective experience of conversational flow. Our data suggest that this process occurs largely beyond individuals' control. We conclude that the form of social interaction is a powerful cue for inferring group solidarity. Implications for the impact of modern communication technology on developing a shared social identity are discussed.

Simulation of diesel engine energy conversion processes

Directory of Open Access Journals (Sweden)

А. С. Афанасьев

2016-12-01

Full Text Available In order to keep diesel engines in good working order the troubleshooting methods shall be improved. For their further improvement by parameters of associated processes a need has arisen to develop a diesel engine troubleshooting method based on time parameters of operating cycle. For such method to be developed a computational experiment involving simulation of diesel engine energy conversion processes has been carried out. The simulation was based on the basic mathematical model of reciprocating internal combustion engines, representing a closed system of equations and relationships. The said model has been supplemented with the engine torque dynamics taking into account the current values of in-cylinder processes with different amounts of fuel injected, including zero feed.The torque values obtained by the in-cylinder pressure conversion does not account for mechanical losses, which is why the base simulation program has been supplemented with calculations for the friction and pumping forces. In order to determine the indicator diagram of idle cylinder a transition to zero fuel feed mode and exclusion of the combustion process from calculation have been provisioned.

Nuclear spin conversion in formaldehyde

OpenAIRE

Chapovsky, Pavel L.

2000-01-01

Theoretical model of the nuclear spin conversion in formaldehyde (H2CO) has been developed. The conversion is governed by the intramolecular spin-rotation mixing of molecular ortho and para states. The rate of conversion has been found equal 1.4*10^{-4}~1/s*Torr. Temperature dependence of the spin conversion has been predicted to be weak in the wide temperature range T=200-900 K.

Rapid determination of methadone and its major metabolite in biological fluids by gas-liquid chromatography with thermionic detection for maintenance treatment of opiate addicts.

Science.gov (United States)

Chikhi-Chorfi, N; Pham-Huy, C; Galons, H; Manuel, N; Lowenstein, W; Warnet, J M; Claude, J R

1998-11-06

A rapid gas-liquid chromatographic assay is developed for the quantification of methadone (Mtd) and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in biological fluids of opiate addicts. After alkaline extraction from samples with lidocaine hydrochloride as internal standard, Mtd and EDDP are separated on SP-2250 column at 220 degrees C and detected with a thermionic detector. The chromatographic time is about 6 min. The relative standard deviations (R.S.D.) of Mtd and EDDP standards are between 1.5 and 5.5%. Most drugs of abuse (morphine, codeine, narcotine, cocaine, benzoylecgonine, cocaethylene, dextropropoxyphene etc) are shown not to interfere with this technique. The method has been applied to study the levels of Mtd and EDDP metabolite in serum, saliva and urine of patients under maintenance treatment for opiate dependence. EDDP levels were found higher than those of Mtd in urine samples from four treated patients, but lower in serum and undetectable in saliva. However, Mtd concentrations were higher in saliva than in serum.

Gene conversion in the rice genome

DEFF Research Database (Denmark)

Xu, Shuqing; Clark, Terry; Zheng, Hongkun

2008-01-01

-chromosomal conversions distributed between chromosome 1 and 5, 2 and 6, and 3 and 5 are more frequent than genome average (Z-test, P ... is not tightly linked to natural selection in the rice genome. To assess the contribution of segmental duplication on gene conversion statistics, we determined locations of conversion partners with respect to inter-chromosomal segment duplication. The number of conversions associated with segmentation is less...... involved in conversion events. CONCLUSION: The evolution of gene families in the rice genome may have been accelerated by conversion with pseudogenes. Our analysis suggests a possible role for gene conversion in the evolution of pathogen-response genes....

Software engineering for the EBR-II data acquisition system conversion

International Nuclear Information System (INIS)

Schorzman, W.

1988-01-01

The purpose of this paper is to outline how EBR-II engineering approached the data acquisition system (DAS) software conversion project with the restraints of operational transparency and six weeks for final implementation and testing. Software engineering is a relatively new discipline that provides a structured philosopy for software conversion. The software life cycle is structured into six basic steps: 1) initiation, 2) requirements definition, 3) design, 4) programming, 5) testing, and 6) operations. These steps are loosely defined and can be altered to fit specific software applications. DAS software is encompassed from three sources: 1) custom software, 2) system software, and 3) in-house application software. A data flow structure is used to describe the DAS software. The categories are: 1) software used to bring signals into the central processer, 2) software that transforms the analog data to engineering units and then logs the data in the data store, and 3) software used to transport and display the data. The focus of this paper is to describe how the conversion team used a structured engineering approach and utilized the resources available to produce a quality system on time. Although successful, the conversion process provided some pit falls and stumbling blocks. Working through these obstacles enhanced our understanding and surfaced in the form of LESSONS LEARNED, which are gracefully shared in this paper

China’s Conversion of Cropland to Forest Program for Household Delivery of Ecosystem Services: How Important is a Local Implementation Regime to Survival Rate Outcomes?

Directory of Open Access Journals (Sweden)

Michael T. Bennett

2014-09-01

Full Text Available China’s Conversion of Cropland to Forests Program (CCFP is the world’s largest afforestation-based Payments for Ecosystem Services (PES program, having retired and afforested over 24 million ha involving 32 million rural households. Prior research has primarily focused on the CCFP’s rural welfare impacts, with few studies on program-induced environmental improvements, particularly at the household level. In this study, data from a 2010 survey covering 2808 rural households from across China was analyzed using an interval regression model to explain household-reported survival rates of trees planted on program-enrolled cropland. In addition to household-level factors, we explore the influence of local conditions and institutional configurations by exploiting the wide diversity of contexts covered by the data set. We find that households with more available labor and more forestry experience manage trees better, but that higher opportunity costs for both land and labor have the opposite effect. We also find that the local implementation regime- e.g., the degree of prior consultation with participants and regular monitoring - has a strong positive effect on reported survivorship. We suggest that the level of subsidy support to participating households will be key to survivorship of trees in planted CCFP forests for some time to come.

Conversation after Right Hemisphere Brain Damage: Motivations for Applying Conversation Analysis

Science.gov (United States)

Barnes, Scott; Armstrong, Elizabeth

2010-01-01

Despite the well documented pragmatic deficits that can arise subsequent to Right Hemisphere Brain Damage (RHBD), few researchers have directly studied everyday conversations involving people with RHBD. In recent years, researchers have begun applying Conversation Analysis (CA) to the everyday talk of people with aphasia. This research programme…

Energy Conversion in Imploding Z-Pinch Plasma

International Nuclear Information System (INIS)

Fisher, V.I.; Gregorian, L.; Davara, G.; Kroupp, E.; Bernshtam, V.A.; Ralchenko, Yu. V.; Starobinets, A.; Maron, Y.

2002-01-01

Due to important applications, Z-pinches became a subject of extensive studies. In these studies, main attention is directed towards improvement in efficiency of electric energy conversion into high-power radiation burst. At present, knowledge available on physics of Z-pinch operation, plasma motion, atomic kinetics, and energy conversion is mainly knowledge of numerical simulation results. We believe further progress require (i) experimental determination of spatial distribution and time history of thermodynamic parameters and magnetic field, as well as (ii) utilization of this data for experiment-based calculation of r,t-distribution of driving forces, mass and energy fluxes, and local energy deposition rates due to each of contributing mechanisms, what provides an insight into a process of conversion of stored electric energy into radiation burst. Moreover, experimentally determined r, t-distribution of parameters may serve for verification of computer programs developed for simulation of Z-pinch operation and optimization of radiation output. Within this research program we performed detailed spectroscopic study of plasmas imploding in modest-size (25 kV, 5 kJ, 1.2 μs quaterperiod) gas-puff Z-pinch. This facility has reasonably high repetition rate and provides good reproducibility of results. Consistent with plasma ionization degree in the implosion period, measurements are performed in UV-visible spectral range. Observation of spectral lines emitted at various azimuthal angles f showed no dependence on f. Dependence on axial coordinate z is found to be weak in near-anode half of the anode-cathode gap. Based on these observations and restricting the measurements to near-anode half of the gap, an evolution of parameters is studied in time and radial coordinate r only. In present talk we report on determination of radial component of plasma hydrodynamic velocity u r (r,t), magnetic field B ζ (r,t), electron density n e (r,t), density of ions in various

Biomass Program 2007 Accomplishments - Full Report

Energy Technology Data Exchange (ETDEWEB)

none,

2009-10-27

The Office of Energy Efficiency and Renewable Energy's (EERE’s) Biomass Program works with industry, academia and its national laboratory partners on a balanced portfolio of research in biomass feedstocks and conversion technologies. This document provides Program accomplishments for 2007.

La conversion de Paul, regards croisés Paul’s conversion. Cross perspectives

Directory of Open Access Journals (Sweden)

Elian Cuvillier

2009-09-01

Full Text Available Au plan historique, les traditions relatives à la conversion de Paul, chutant de son cheval sur le chemin de Damas, confrontent l’exégète à trois problèmes importants : y avait-il un cheval, cela se passait-il sur le chemin de Damas et était-ce bien une conversion ? Entendues avec l’humour et la distance critique nécessaires, ces trois questions constituent les trois chapitres de cet article. Le premier « Y avait-il un cheval ? » s’intéresse à l’histoire de la réception de l’épisode de la conversion de Paul, en particulier dans la peinture et la littérature. Le second « Cela se passait-il sur le chemin de Damas ? » est consacrée au récit que l’auteur du livre des Actes propose de la conversion de Paul, récit qui constitue, bien souvent, la porte d’entrée exclusive pour aborder le thème. Le troisième « Etait-ce bien une conversion ? » analyse les témoignages de l’apôtre lui-même à travers deux passages clés de ses épîtres authentiques.Historically speaking, the traditions concerning the conversion of Paul, falling from his horse on the road to Damascus, confront the exegete with three important problems : was there a horse, did it happen on the road to Damacus and was it really a conversion ? These three questions, considered with humor and critical distance, constitute the three sections of this article. The first part « Was there a horse ? » considers the history of the reception of the episode of the conversion of Paul, particularly in art and literature. The second one « Did it happen on the road to Damascus ? » is devoted to the story of the conversion of Paul proposed by the author of the book of Acts, which is very often the exclusive entrance to the discussion of this theme. The third section « Was it really a conversion ? » analyzes the account given by the apostle himself in two key passages of his authentic epistles.

Status report on nuclear electric propulsion systems

Science.gov (United States)

Stearns, J. W.

1975-01-01

Progress in nuclear electric propulsion (NEP) systems for a multipayload multimission vehicle needed in both deep-space missions and a variety of geocentric missions is reviewed. The space system power level is a function of the initial launch vehicle mass, but developments in out-of-core nuclear thermionic direct conversion have broadened design options. Cost, design, and performance parameters are compared for reusable chemical space tugs and NEP reusable space tugs. Improvements in heat pipes, ion engines, and magnetoplasmadynamic arc jet thrust subsystems are discussed.

Reduction of Linear Programming to Linear Approximation

OpenAIRE

Vaserstein, Leonid N.

2006-01-01

It is well known that every Chebyshev linear approximation problem can be reduced to a linear program. In this paper we show that conversely every linear program can be reduced to a Chebyshev linear approximation problem.

Conversational Agents in E-Learning

Science.gov (United States)

Kerry, Alice; Ellis, Richard; Bull, Susan

This paper discusses the use of natural language or 'conversational' agents in e-learning environments. We describe and contrast the various applications of conversational agent technology represented in the e-learning literature, including tutors, learning companions, language practice and systems to encourage reflection. We offer two more detailed examples of conversational agents, one which provides learning support, and the other support for self-assessment. Issues and challenges for developers of conversational agent systems for e-learning are identified and discussed.

Chronic subjective dizziness versus conversion disorder: discussion of clinical findings and rehabilitation.

Science.gov (United States)

Honaker, Julie A; Gilbert, Jane M; Staab, Jeffrey P

2010-06-01

Audiologists frequently encounter patients who complain of chronic dizziness or imbalance, in the absence of active vestibular or neurological deficits. Knowledge about conditions that cause this clinical presentation will allow audiologists to make important contributions to accurate diagnosis and effective management of these patients. This article reviews 2 such conditions, chronic subjective dizziness (CSD) and conversion disorder. A case of CSD and another of conversion disorder are presented, with a literature review of their clinical presentations, key diagnostic features, and treatment strategies. The role of the audiologist in assessing patients with these conditions and facilitating appropriate treatment referrals is discussed. The audiologist is in a key position to identify individuals with CSD and conversion disorder, 2 conditions that can be effectively managed if properly recognized. The authors demonstrate an effective team approach program that includes the audiologist's contribution to differential diagnosis, education of patients and other clinicians about these conditions, and development of recommendations for neurological, psychiatric, otologic, and physical therapy referrals.

Boiler conversions for biomass

Energy Technology Data Exchange (ETDEWEB)

Kinni, J [Tampella Power Inc., Tampere (Finland)

1997-12-31

Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

Boiler conversions for biomass

Energy Technology Data Exchange (ETDEWEB)

Kinni, J. [Tampella Power Inc., Tampere (Finland)

1996-12-31

Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

Strong and reversible modulation of carbon nanotube-silicon heterojunction solar cells by an interfacial oxide layer.

Science.gov (United States)

Jia, Yi; Cao, Anyuan; Kang, Feiyu; Li, Peixu; Gui, Xuchun; Zhang, Luhui; Shi, Enzheng; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

2012-06-21

Deposition of nanostructures such as carbon nanotubes on Si wafers to make heterojunction structures is a promising route toward high efficiency solar cells with reduced cost. Here, we show a significant enhancement in the cell characteristics and power conversion efficiency by growing a silicon oxide layer at the interface between the nanotube film and Si substrate. The cell efficiency increases steadily from 0.5% without interfacial oxide to 8.8% with an optimal oxide thickness of about 1 nm. This systematic study reveals that formation of an oxide layer switches charge transport from thermionic emission to a mixture of thermionic emission and tunneling and improves overall diode properties, which are critical factors for tailoring the cell behavior. By controlled formation and removal of interfacial oxide, we demonstrate oscillation of the cell parameters between two extreme states, where the cell efficiency can be reversibly altered by a factor of 500. Our results suggest that the oxide layer plays an important role in Si-based photovoltaics, and it might be utilized to tune the cell performance in various nanostructure-Si heterojunction structures.

Solar energy conversion systems

CERN Document Server

Brownson, Jeffrey R S

2013-01-01

Solar energy conversion requires a different mind-set from traditional energy engineering in order to assess distribution, scales of use, systems design, predictive economic models for fluctuating solar resources, and planning to address transient cycles and social adoption. Solar Energy Conversion Systems examines solar energy conversion as an integrative design process, applying systems thinking methods to a solid knowledge base for creators of solar energy systems. This approach permits different levels of access for the emerging broad audience of scientists, engineers, architects, planners

The creative use of unexpected responses in the hypnotherapy of patients with conversion disorders

NARCIS (Netherlands)

Moene, F.C.; Hoogduin, C.A.L.

1999-01-01

In a previously completed empirical study examining the use of hypnosis in a comprehensive treatment program with 85 patients who suffered motor conversion symptoms, 16 patients were reported by their therapists to have had unusual and unexpected responses during hypnosis. This article summarizes

Assessment of BSBA Students' Conversancy in Current Business Issues: A Case Study

Science.gov (United States)

Hogan, Eileen A.; Maskulka, Therese A.; Kaminski, Kathleen A.

2014-01-01

In 2008, the faculty of the College of Business at Kutztown University developed a set of five learning goals for its BSBA program. In fall, 2011, the college's Assurance of Learning Committee began to pursue the assessment of the last of these goals: "BSBA graduates will be conversant in current business issues, including ethics, social…

Direct conversion of fusion energy

International Nuclear Information System (INIS)

Johansson, Markus

2003-03-01

Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D- 3 He reaction and the p- 11 B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger βB 2 0 to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high β values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D- 3 He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D 3 He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D 3 He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion or liquid metal MHD conversion (LMMHD). For a D

Direct conversion of fusion energy

Energy Technology Data Exchange (ETDEWEB)

Johansson, Markus

2003-03-01

Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D-{sup 3}He reaction and the p-{sup 11}B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger {beta}B{sup 2}{sub 0} to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high {beta} values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D-{sup 3}He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D{sub 3} He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D{sub 3} He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion

[Neuropsychological assessment in conversion disorder].

Science.gov (United States)

Demır, Süleyman; Çelıkel, Feryal Çam; Taycan, Serap Erdoğan; Etıkan, İlker

2013-01-01

Conversion disorder is characterized by functional impairment in motor, sensory, or neurovegetative systems that cannot be explained by a general medical condition. Diagnostic systems emphasize the absence of an organic basis for the dysfunction observed in conversion disorder. Nevertheless, there is a growing body of data on the specific functional brain correlates of conversion symptoms, particularly those obtained via neuroimaging and neurophysiological assessment. The present study aimed to determine if there are differences in measures of cognitive functioning between patients with conversion disorder and healthy controls. The hypothesis of the study was that the patients with conversion disorder would have poorer neurocognitive performance than the controls. The patient group included 43 patients diagnosed as conversion disorder and other psychiatric comorbidities according to DSM-IV-TR. Control group 1 included 44 patients diagnosed with similar psychiatric comorbidities, but not conversion diosorder, and control group 2 included 43 healthy individuals. All participants completed a sociodemographic questionnaire and were administered the SCID-I and a neuropsychological test battery of 6 tests, including the Serial Digit Learning Test (SDLT), Auditory Verbal Learning Test (AVLT), Wechsler Memory Scale, Stroop Color Word Interference Test, Benton Judgment of Line Orientation Test (BJLOT), and Cancellation Test. The patient group had significantly poorer performance on the SDLT, AVLT, Stroop Color Word Interference Test, and BJLOT than both control groups. The present findings highlight the differences between the groups in learning and memory, executive and visuospatial functions, and attention, which seemed to be specific to conversion disorder.

The effects of the use of a conversational model and opportunities for reflections in computer-based role playing

NARCIS (Netherlands)

Holsbrink-Engels, G.A.

1997-01-01

This study examined the effects of an instructional program on 21-year-old students' interpersonal skills development (N = 104). The HyperCard 2.1 program ¿Telling bad news¿ could contain a conversational model that informed students about the main moments and actions in conducting a bad-news

SEGY to ASCII Conversion and Plotting Program 2.0

Science.gov (United States)

Goldman, Mark R.

2005-01-01

INTRODUCTION SEGY has long been a standard format for storing seismic data and header information. Almost every seismic processing package can read and write seismic data in SEGY format. In the data processing world, however, ASCII format is the 'universal' standard format. Very few general-purpose plotting or computation programs will accept data in SEGY format. The software presented in this report, referred to as SEGY to ASCII (SAC), converts seismic data written in SEGY format (Barry et al., 1975) to an ASCII data file, and then creates a postscript file of the seismic data using a general plotting package (GMT, Wessel and Smith, 1995). The resulting postscript file may be plotted by any standard postscript plotting program. There are two versions of SAC: one version for plotting a SEGY file that contains a single gather, such as a stacked CDP or migrated section, and a second version for plotting multiple gathers from a SEGY file containing more than one gather, such as a collection of shot gathers. Note that if a SEGY file has multiple gathers, then each gather must have the same number of traces per gather, and each trace must have the same sample interval and number of samples per trace. SAC will read several common standards of SEGY data, including SEGY files with sample values written in either IBM or IEEE floating-point format. In addition, utility programs are present to convert non-standard Seismic Unix (.sux) SEGY files and PASSCAL (.rsy) SEGY files to standard SEGY files. SAC allows complete user control over all plotting parameters including label size and font, tick mark intervals, trace scaling, and the inclusion of a title and descriptive text. SAC shell scripts create a postscript image of the seismic data in vector rather than bitmap format, using GMT's pswiggle command. Although this can produce a very large postscript file, the image quality is generally superior to that of a bitmap image, and commercial programs such as Adobe Illustrator

Changing the conversation: the influence of emotions on conversational valence and alcohol consumption.

Science.gov (United States)

Hendriks, Hanneke; van den Putte, Bas; de Bruijn, Gert-Jan

2014-10-01

Health campaign effects may be improved by taking interpersonal communication processes into account. The current study, which employed an experimental, pretest-posttest, randomized exposure design (N = 208), investigated whether the emotions induced by anti-alcohol messages influence conversational valence about alcohol and subsequent persuasion outcomes. The study produced three main findings. First, an increase in the emotion fear induced a negative conversational valence about alcohol. Second, fear was most strongly induced by a disgusting message, whereas a humorous appeal induced the least fear. Third, a negative conversational valence elicited healthier binge drinking attitudes, subjective norms, perceived behavioral control, intentions, and behaviors. Thus, health campaign planners and health researchers should pay special attention to the emotional characteristics of health messages and should focus on inducing a healthy conversational valence.

Biomass Program 2007 Accomplishments - Report Introduction

Energy Technology Data Exchange (ETDEWEB)

none,

2009-10-27

The Office of Energy Efficiency and Renewable Energy's (EERE’s) Biomass Program works with industry, academia and its national laboratory partners on a balanced portfolio of research in biomass feedstocks and conversion technologies. This document provides the introduction to the 2007 Program Accomplishments Report.

Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol

Energy Technology Data Exchange (ETDEWEB)

None

2011-05-02

The U.S. Department of Energy (DOE) promotes the production of ethanol and other liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in the program, the National Renewable Energy Laboratory (NREL) investigates the production economics of these fuels.

Advanced energy sources and conversion techniques. Proceedings of a seminar. Volume 1. [35 papers

Energy Technology Data Exchange (ETDEWEB)

None

1958-11-01

The Seminar was organized as a series of tutorial presentations and round table discussions on a technical level to implement the following: (a) to identify and explore present and projected needs for energy sources and conversion techniques for military applications; (b) to exchange information on current and planned efforts in these fields; (c) to examine the effect of anticipated scientific and technological advances on these efforts; and (d) to present suggested programs aimed at satisfying the military needs for energy sources and conversion techniques. Volume I contains all of the unclassified papers presented at the Seminar. (W.D.M.)

Special issue: Plasma Conversion

NARCIS (Netherlands)

Nozaki, T.; Bogaerts, A.; Tu, X.; van de Sanden, M. C. M.

2017-01-01

With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the

Investigation of modeling and simulation on a PWR power conversion system with RELAP5

International Nuclear Information System (INIS)

Rui Gao; Yang Yanhua; Lin Meng; Yuan Minghao; Xie Zhengrui

2007-01-01

Based on the power conversion system of nuclear and conventional islands of Dayabay nuclear power station, this paper models the thermal-hydraulic systems for PWR by using the best-estimate program, RELAP5. To simulate the full-scope power conversion system, not only the reactor coolant system (RCP) of nuclear island, but also the main steam system (VVP), turbine steam and drain system (GPV), bypass system (GCT), feedwater system (FW), condensate extraction system (CEX), moisture separator reheater system (GSS), turbine-driven feedwater pump (APP), low-pressure and high-pressure feedwater heater systems (ABP and AHP) of conventional island are considered and modeled. A comparison between the simulated results and the actual data of reactor under full-power demonstrates a fine match for Dayabay, and also manifests the feasibility in simulating full-scope power conversion system of PWR with RELAP5. (author)

Papa, a Particle Tracing Code in Pascal

NARCIS (Netherlands)

Haselhoff, E.H.; Haselhoff, Eltjo H.; Ernst, G.J.

1990-01-01

During the design of a 10 ¿m high-gain FEL oscillator (TEUFEL Project) we developed a new particle-tracing code to perform simulations of thermionic- and photo-cathode electron injectors/accelerators. The program allows predictions of current, energy and beam emittance in a user-specified linac

HEU core conversion of Russian production reactors: a major threat to the international RERTR regime

International Nuclear Information System (INIS)

Kuperman, Alan J.; Leventhal, Paul L.

1998-01-01

This paper calls the attention for the major threat to the International Reduced Enrichment for Research and Test Reactors (RERTR) program, represented by the HEU core conversion of russian production reactors. This program aims to reduce and eventually eliminate international civilian commerce in nuclear weapons-usable, highly enriched uranium , and thereby significantly lower risks of the material being stolen or diverted by terrorist or states for producing nuclear weapons

Increasing conversion efficiency of two-step photon up-conversion solar cell with a voltage booster hetero-interface.

Science.gov (United States)

Asahi, Shigeo; Kusaki, Kazuki; Harada, Yukihiro; Kita, Takashi

2018-01-17

Development of high-efficiency solar cells is one of the attractive challenges in renewable energy technologies. Photon up-conversion can reduce the transmission loss and is one of the promising concepts which improve conversion efficiency. Here we present an analysis of the conversion efficiency, which can be increased by up-conversion in a single-junction solar cell with a hetero-interface that boosts the output voltage. We confirm that an increase in the quasi-Fermi gap and substantial photocurrent generation result in a high conversion efficiency.

Direct Neural Conversion from Human Fibroblasts Using Self-Regulating and Nonintegrating Viral Vectors

Directory of Open Access Journals (Sweden)

Shong Lau

2014-12-01

Full Text Available Summary: Recent findings show that human fibroblasts can be directly programmed into functional neurons without passing via a proliferative stem cell intermediate. These findings open up the possibility of generating subtype-specific neurons of human origin for therapeutic use from fetal cell, from patients themselves, or from matched donors. In this study, we present an improved system for direct neural conversion of human fibroblasts. The neural reprogramming genes are regulated by the neuron-specific microRNA, miR-124, such that each cell turns off expression of the reprogramming genes once the cell has reached a stable neuronal fate. The regulated system can be combined with integrase-deficient vectors, providing a nonintegrative and self-regulated conversion system that rids problems associated with the integration of viral transgenes into the host genome. These modifications make the system suitable for clinical use and therefore represent a major step forward in the development of induced neurons for cell therapy. : Lau et al. now use miRNA targeting to build a self-regulating neural conversion system. Combined with nonintegrating vectors, this system can efficiently drive conversion of human fibroblasts into functional induced neurons (iNs suitable for clinical applications.

Ownership conversions and nursing home performance.

Science.gov (United States)

Grabowski, David C; Stevenson, David G

2008-08-01

To examine the effects of ownership conversions on nursing home performance. Online Survey, Certification, and Reporting system data from 1993 to 2004, and the Minimum Data Set (MDS) facility reports from 1998 to 2004. Regression specification incorporating facility fixed effects, with terms to identify trends in the pre- and postconversion periods. The annual rate of nursing home conversions almost tripled between 1994 and 2004. Our regression results indicate converting facilities are generally different throughout the pre/postconversion years, suggesting little causal effect of ownership conversions on nursing home performance. Before and after conversion, nursing homes converting from nonprofit to for-profit status generally exhibit deterioration in their performance, while nursing homes converting from for-profit to nonprofit status generally exhibit improvement. Policy makers have expressed concern regarding the implications of ownership conversions for nursing home performance. Our results imply that regulators and policy makers should not only monitor the outcomes of nursing home conversions, but also the targets of these conversions.

The effects of spots (or grains) and the mean work function of a polycrystalline emitter

International Nuclear Information System (INIS)

Devin, B.; Phuc Nguyen, Xuan

1964-01-01

The direct conversion of thermal energy at high temperature to electrical energy using plasma diodes is studied in the Electronic Physics Service of the French Atomic Energy Commission. Research concerns the adaptation of these diodes to nuclear reactors with a view especially to providing power for operating the instruments of space vehicles. In parallel with the semi-industrial realizations and tests, an important part of the activity of the service is directed towards fundamental research into physical phenomena convected with thermionic emission with a view to improving present performances. (authors) [fr

Hydrothermal conversion of biomass

NARCIS (Netherlands)

Knezevic, D.

2009-01-01

This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of

Starting a Conversation: Engaging Scientists with the Public through Interactive Activities

Science.gov (United States)

Bartel, B. A.; Charlevoix, D. J.

2016-12-01

While demonstrations are a handy tool, research shows conversations are an even more effective way to have a lasting impact. UNAVCO joined the Portal to the Public Network (PoPNet) in March 2016 to offer PoPNet-style hands-on communication training to the geodetic scientific community. Portal to the Public is a system of professional development tools designed to better connect scientists and the public in positive dialogue, in informal education settings such as museums. The framework focuses not on one-way messaging, but on conversations. PoPNet is the network of museums and other institutions implementing PoP training. UNAVCO developed and launched a pilot program in summer 2016 with a cohort of graduate students. In the PoPNet model, museums bring local scientists to the museum to learn about and practice science communication to the general public. UNAVCO does not have a museum but rather is an international community of geoscientists who can receive training on informal communications and then practice their skills at a museum local to them. The skills learned are useful in communicating science not only to the public, but also to policy makers, funders, and anyone outside the immediate scientific discipline. Developing communications skills also encourages scientists to think more holistically about their research and its impacts.In the 2016 pilot program, UNAVCO offered a seven-week workshop to UNAVCO Student Internship Program (USIP) interns. The students spent two hours per week working on communication skills through hands-on activities and discussions, and developed tabletop activities based on their research. These tabletop activities are hands-on demonstrations of scientific concepts such as tsunami early warning and volcano deformation designed for interaction rather than one-way show-and-tell. The program culminated in an evening with the tabletop activities at the Boulder County Farmers Market. All six participating interns indicated on the exit

Conversational Styles and Misunderstanding in Cross-Sex Conversations in He’s Just Not That into You Movie

Directory of Open Access Journals (Sweden)

Ayu Nyoman Aryani

2017-01-01

Full Text Available Conversation is a social interaction among societies. In this case, gender differences in daily communication lead to men’s and women’s different point of views in performing styles of the conversations. Misunderstanding is likely to occur in crosssex conversations when the idea or thought are understood differently by men and women. This study was intended to analyze the use of conversational styles by men and women and also investigate the misunderstanding phenomena that happened in cross-sex conversations. The researcher identified that the conversational styles used by Alex as a male character in the cross-sex conversations were qualifiers, controlling the topics, verbal fillers, intensifiers, swear words, compound requests, tag questions, questions, interruptions, overlapping, and talk domination. Meanwhile, Gigi, as a female character used qualifiers, controlling the topics, verbal fillers, intensifiers, swear words, tag questions, questions, interruptions, overlapping, talk domination, and silence. In answering the second question, the researcher discovered factors that affected the misunderstanding in the cross-sex conversations between Alex and Gigi were involvement versus independence and message versus metamessage.   DOI: https://doi.org/10.24071/llt.2016.190101

Vertical Scan-Conversion for Filling Purposes

OpenAIRE

Hersch, R. D.

1988-01-01

Conventional scan-conversion algorithms were developed independently of filling algorithms. They cause many problems, when used for filling purposes. However, today's raster printers and plotters require extended use of filling, especially for the generation of typographic characters and graphic line art. A new scan-conversion algorithm, called vertical scan-conversion has been specifically designed to meet the requirements of parity scan line fill algorithms. Vertical scan-conversion ensures...

Trends in Modern War Gaming: The Art of Conversation

Science.gov (United States)

2014-01-01

War Gaming: The Art of Conversation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...conflict to the sum of its parts. In 1916, frederick lanchester, a brit- ish mathematician , sought to apply two equations—the law of squares to “‘aimed...differences “cannot be comprehended by linear models.”36 the american physicist and author fritjof Capra notes that “the process of model making consists

The Energy Conversion Analysis of HTR Gas Turbine System

International Nuclear Information System (INIS)

Utaja

2000-01-01

The energy conversion analysis of HTR gas turbine system by hand calculation is tedious work and need much time. This difficulty comes from the repeated thermodynamic process calculation, both on compression or expansion of the cycle. To make the analysis faster and wider variable analyzed, HTR-1 programme is used. In this paper, the energy conversion analysis of HTR gas turbine system by HTR-1 will be described. The result is displayed as efficiency curve and block diagram with the input and output temperature of the component. This HTR-1 programme is developed by Basic language programming and be compiled by Visual Basic 5.0 . By this HTR-1 programme, the efficiency, specific power and effective compression of the amount of gas can be recognized fast. For example, for CO 2 gas between 40 o C and 700 o C, the compression on maximum efficiency is 4.6 and the energy specific is 18.9 kcal/kg, while the temperature changing on input and output of the component can be traced on monitor. This process take less than one second, while the manual calculation take more than one hour. It can be concluded, that the energy conversion analysis of the HTR gas turbine system by HTR-1 can be done faster and more variable analyzed. (author)

Optical analysis of down-conversion OLEDs

Science.gov (United States)

Krummacher, Benjamin; Klein, Markus; von Malm, Norwin; Winnacker, Albrecht

2008-02-01

Phosphor down-conversion of blue organic light-emitting diodes (OLEDs) is one approach to generate white light, which offers the possibility of easy color tuning, a simple device architecture and color stability over lifetime. In this article previous work on down-conversion devices in the field of organic solid state lighting is briefly reviewed. Further, bottom emitting down-conversion OLEDs are studied from an optical point of view. Therefore the physical processes occurring in the down-conversion layer are translated into a model which is implemented in a ray tracing simulation. By comparing its predictions to experimental results the model is confirmed. For the experiments a blue-emitting polymer OLED (PLED) panel optically coupled to a series of down-conversion layers is used. Based on results obtained from ray tracing simulation some of the implications of the model for the performance of down-conversion OLEDs are discussed. In particular it is analysed how the effective reflectance of the underlying blue OLED and the particle size distribution of the phosphor powder embedded in the matrix of the down-conversion layer influence extraction efficiency.

NREL biofuels program overview

Energy Technology Data Exchange (ETDEWEB)

Mielenz, J.R. [National Renewable Energy Laboratory, Golden, CO (United States)

1996-09-01

The NREL Biofuels Program has been developing technology for conversion of biomass to transportation fuels with support from DOE Office of Transportation Technologies Biofuels System Program. This support has gone to both the National Renewable Energy Laboratory, and over 100 subcontractors in universities and industry. This overview will outline the value of the Biofuels development program to the Nation, the current status of the technology development, and what research areas still need further support and progress for the development of a biofuels industry in the US.

Responsive turns in Indonesian informal conversation

Directory of Open Access Journals (Sweden)

M.J. van Naerssen

2015-04-01

Full Text Available People have all sorts of expectations about how interlocutors will and should behave linguistically when engaged in a conversation. These conversational norms are usually implicit and are sometimes difficult to master in a language that is new to you. This paper presents a model of different types of responses in informal conversation, illustrated with Indonesian examples. It builds upon the conversation analytic notion of preference; distinguishing preferred – or constructive – responses and dispreferred – or competitive – responses. The model is meant as a tool to cross-linguistically compare response behaviour to gain insight in language specific expectations about interaction in informal conversation.

An exploration of contextual dimensions impacting goals of care conversations in postgraduate medical education.

Science.gov (United States)

Roze des Ordons, Amanda L; Lockyer, Jocelyn; Hartwick, Michael; Sarti, Aimee; Ajjawi, Rola

2016-03-21

Postgraduate medical trainees are not well prepared difficult conversations about goals of care with patients and families in the acute care clinical setting. While contextual nuances within the workplace can impact communication, research to date has largely focused on individual communication skills. Our objective was to explore contextual factors that influence conversations between trainees and patients/families about goals of care in the acute care setting. We conducted an exploratory qualitative study involving five focus groups with Internal Medicine trainees (n = 20) and a series of interviews with clinical faculty (n = 11) within a single Canadian centre. Thematic framework analysis was applied to categorize the data and identify themes and subthemes. Challenges and factors enabling goals of care conversations emerged within individual, interpersonal and system dimensions. Challenges included inadequate preparation for these conversations, disconnection between trainees, faculty and patients, policies around documentation, the structure of postgraduate medical education, and resource limitations; these challenges led to missed opportunities, uncertainty and emotional distress. Enabling factors were awareness of the importance of goals of care conversations, support in these discussions, collaboration with colleagues, and educational initiatives enabling skill development; these factors have resulted in learning, appreciation, and an established foundation for future educational initiatives. Contextual factors impact how postgraduate medical trainees communicate with patients/families about goals of care. Attention to individual, interpersonal and system-related factors will be important in designing educational programs that help trainees develop the capacities needed for challenging conversations.

Conversation Simulation and Sensible Surprises

Science.gov (United States)

Hutchens, Jason L.

I have entered the Loebner Prize five times, winning the "most humanlike program" category in 1996 with a surly ELIZA-clone named HeX, but failed to repeat the performance in subsequent years with more sophisticated techniques. Whether this is indicative of an unanticipated improvement in "conversation simulation" technology, or whether it highlights the strengths of ELIZA-style trickery, is as an exercise for the reader. In 2000, I was invited to assume the role of Chief Scientist at Artificial Intelligence Ltd. (Ai) on a project inspired by the advice given by Alan Turing in the final section of his classic paper - our quest was to build a "child machine" that could learn and use language from scratch. In this chapter, I will discuss both of these experiences, presenting my thoughts regarding the Chinese Room argument and Artificial Intelligence (AI) in between.

Conversations in African Philosophy

African Journals Online (AJOL)

JONATHAN

Conversational philosophy is articulated by Jonathan O. Chimakonam as the new wave of philosophical practice both in “place” and in “space”. This journal adopts and promotes this approach to philosophizing for African philosophy. Readers are encouraged to submit their conversational piece (maximum of 2000 words) ...

Predictability of Conversation Partners

Science.gov (United States)

Takaguchi, Taro; Nakamura, Mitsuhiro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki

2011-08-01

Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song , ScienceSCIEAS0036-8075 327, 1018 (2010)] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.

Predictability of Conversation Partners

Directory of Open Access Journals (Sweden)

Taro Takaguchi

2011-09-01

Full Text Available Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song et al., Science 327, 1018 (2010SCIEAS0036-8075] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.

Conversion of DAP models to SPEEDUP

International Nuclear Information System (INIS)

Aull, J.E.

1993-08-01

Several processes at the Savannah River Site are modeled using Bechtel's Dynamic Analysis Program (DAP) which uses a sequential modular modeling architecture. The feasibility of conversion of DAP models to SPEEDUP was examined because of the benefits associated with this de facto industry standard. The equation-based approach used in SPEEDUP gives accuracy, stability, and ease of maintenance. The DAP licenses on our site are for single-user PS/2 machines whereas the SPEEDUP product is licensed on a VAX minicomputer which provides faster execution and ease of integration with existing visualization tools. In this paper the basic unit operations of a DAP model that simulates a ventilation system are described. The basic operations were modeled with both DAP and SPEEDUP, and the two models yield results that are in close agreement. Since the basic unit operations of the DAP model have been successfully duplicated using SPEEDUP, it is feasible to proceed with model conversion. DAP subroutines and functions that involve only algebraic manipulation may be inserted directly into the SPEEDUP model or their underlying equations may be extracted and written as SPEEDUP model equations. A problem modeled in SPEEDUP running on a VAX 8810 runs approximately fifteen times faster in elapsed time than the same problem modeled with DAP on a 33 MHz Intel 80486 processor

Statistical thermodynamics foundation for photovoltaic and photothermal conversion. II. Application to photovoltaic conversion

Science.gov (United States)

Badescu, Viorel; Landsberg, Peter T.

1995-08-01

The general theory developed in part I was applied to build up two models of photovoltaic conversion. To this end two different systems were analyzed. The first system consists of the whole absorber (converter), for which the balance equations for energy and entropy are written and then used to derive an upper bound for solar energy conversion. The second system covers a part of the absorber (converter), namely the valence and conduction electronic bands. The balance of energy is used in this case to derive, under additional assumptions, another upper limit for the conversion efficiency. This second system deals with the real location where the power is generated. Both models take into consideration the radiation polarization and reflection, and the effects of concentration. The second model yields a more accurate upper bound for the conversion efficiency. A generalized solar cell equation is derived. It is proved that other previous theories are particular cases of the present more general formalism.

Symposium proceedings: environmental aspects of fuel conversion technology, IV (April 1979, Hollywood, FL)

Energy Technology Data Exchange (ETDEWEB)

Ayer, F.A.; Jones, N.S. (comps.)

1979-09-01

The proceedings document presentations made at the symposium on Environmental Aspects of Fuel Conversion Technology are presented. The symposium acted as a colloquium for discussion of environmentally related information on coal gasification and liquefaction. The program included sessions on program approach, environmental assessment, and control technology development. Process developers, process users, research scientists and state and federal government officials participated in this symposium, the fourth to be conducted by IERL-RTP on the subject since 1974. Separate abstracts have been prepared of individual presentations for inclusion in the Energy Data Base.

Frequency conversion of structured light.

Science.gov (United States)

Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P

2016-02-15

Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.

Overcoming difficult conversations in clinical supervision

Directory of Open Access Journals (Sweden)

Williams B

2016-06-01

Full Text Available Brett Williams,1 Christine King,1 Tanya Edlington,21Department of Community Emergency Health and Paramedic Practice, Monash University, Franskton, VIC, 2The Conversation Clinic Pty Ltd, Melbourne, VIC, Australia Background: Clinical supervisors are responsible for managing many facets of clinical learning and face a range of challenges when the need for "difficult" conversations arises, including the need to manage conflict and relationships. Methods: Spotlight on Conversations Workshop was developed to improve the capacity of clinical supervisors to engage in difficult conversations. They were designed to challenge the mindset of clinical supervisors about difficult conversations with students, the consequences of avoiding difficult conversations, and to offer activities for practicing difficult conversations. Preworkshop, postworkshop, and 4-month follow-up evaluations assessed improvements in knowledge, intent to improve, and confidence along with workshop satisfaction. Results: Nine workshops were delivered in a range of locations across Victoria, Australia, involving a total of 117 clinical supervisors. Preworkshop evaluations illustrated that more than half of the participants had avoided up to two difficult conversations in the last month in their workplace. Postworkshop evaluation at 4 months showed very high levels of satisfaction with the workshop's relevancy, content, and training, as well as participants' intention to apply knowledge and skills. Also shown were significant changes in participants' confidence to have difficult conversations not only with students but also with other peers and colleagues. In follow-up in-depth interviews with 20 of the 117 participants, 75% said they had made definite changes in their practice because of what they learned in the workshop and another 10% said they would make changes to their practice, but had not had the opportunity yet to do so. Conclusion: We conclude that the Spotlight on

Paradoxical therapy in conversion disorder

OpenAIRE

ATAOĞLU, Ahmet

1998-01-01

Paradoxical therapy consists of suggesting that the patient intentionally engages in the unwanted behaviour, such as performing complusive ritual or bringing on a conversion attack. In this study paradoxical intention (PI) was used with to half of the patients with conversion disorders, while the other half were treated with diazepam in order to examine the efficiency of the PI versus diazepam in conversion disorder. Patients treated with PI appeared to have a greater improvement r...

Asynchronous Knowledge Sharing and Conversation Interaction Impact on Grade in an Online Business Course

Science.gov (United States)

Strang, Kenneth David

2011-01-01

Student knowledge sharing and conversation theory interactions were coded from asynchronous discussion forums to measure the effect of learning-oriented utterances on academic performance. The sample was 3 terms of an online business course (in an accredited MBA program) at a U.S.-based university. Correlation, stepwise regression, and multiple…

PENGEMBANGAN ENERGI TERBARUKAN MELALUI EVALUASI PROGRAM KONVERSI MINYAK TANAH KE LPG DI PULAU GILI RAJA-SUMENEP (Developing Renewable Energy Through An Evaluation for A Program of Kerosene Conversion to LPG in Gili Raja Island - Sumenep

Directory of Open Access Journals (Sweden)

Nian Riawati

2014-10-01

Full Text Available ABSTRAK Penelitian ini mengevaluasi program konversi minyak tanah ke Liquefied Petroleum Gas (LPG pada kelompok sasaran di pulau Gili Raja kabupaten Sumenep Jawa Timur. Kajian sebelumnya terhadap program ini masih bersifat formatif dengan fokus efisiensi dan efektivitas implementasi. Dengan menggunakan metode Minimum Evaluation Procedure (MEP penelitian ini mempertanyakan implementasi program secara runtut, mulai output, outcome sampai impact. Melalui pendekatan kualitatif penelitian ini dapat mendeskripsikan konteks dan setting secara alamiah. Hasil penelitian menunjukkan adanya pungutan dalam proses distribusi paket program, rendahnya akses atau penggunaan paket program serta tidak adanya dampak program. Selain itu, ditemukan adanya potensi lokal berupa kotoran ternak yang dapat dikembangkan menjadi sumber daya energi terbarukan. Berdasarkan hal itu, disarankan sebuah program dapat dikembangkan secara asimetris sesuai dengan kondisi lokasi dan kelompok sasaran, terjadinya komunikasi intensif antara pelaksana program dengan kelompok sasaran serta stakeholders lainnya. Berdasarkan potensi kelompok sasaran di pulau Gili Raja, hendaknya dikembangkan kebijakan energi alternatif biogas untuk memenuhi kebutuhan energi masyarakat serta mendukung pencapaian tujuan kebijakan energi nasional.   ABSTRACT The purpose of this research is to evaluate the conversion programfrom kerosene to Liquefied Petroleum Gas (LPG on a target group in Gili Raja island of SumenepMunicipal, East Java. Previous study on this program was quite formative one and focusing on the efficiency and the effectiveness of the program implementation. In addition, by applying Minimum Evaluation Procedure’s (MEP method, this research questioned the implementation of the program consecutively from the output, the outcome as well as the impact. Furthermore, through a qualitative approach, this research will be able to describe context and setting naturally. Result of the research shows

Participation in the Journey to Life Conversation Map Improves Control of Hypertension, Diabetes, and Hypercholesterolemia.

Science.gov (United States)

Crawford, Paul; Wiltz, Scott

2015-01-01

The Diabetes Conversation Map program includes 4 "board game-like" education tools. We describe how the Journey to Life Conversation Map Education Class improves diabetes performance measures of hemoglobin A1c (HbA1c), low-density lipoprotein (LDL), and blood pressure (BP). Retrospective case-control study in a military family medicine clinic from January 2007 to January 2010. We included 202 patients who completed ≥1 conversation map class and a comparison group of 209 patients who did not attend. Attendees started with HbA1c 8.25 (95% confidence interval [CI], 7.86-8.64) and decreased to 6.96 (95% CI, 6.69-7.23). Patients in the comparison group started at 8.57 (95% CI, 8.18-8.95) and decreased to 8.27 (95% CI, 8.01-8.54) (P Board of Family Medicine.

Microwave plasma mode conversion

International Nuclear Information System (INIS)

Torres, H.S.; Sakanaka, P.H.; Villarroel, C.H.

1985-01-01

The behavior of hot electrons during the process of laser-produced plasma is studied. The basic equations of mode conversion from electromagnetic waves to electrostatic waves are presented. It is shown by mode conversion, that, the resonant absorption and parametric instabilities appear simultaneously, but in different plasma regions. (M.C.K.) [pt

Conversing as Metaphor of Human Thinking: Is Mind like a Conversation?

Science.gov (United States)

Sorsana, Christine; Trognon, Alain

2018-06-01

How can researchers shape their ideas so that they understand the mind better? This theoretical paper discusses the merits of the conversation metaphor as a means of analyzing the human mind. We will develop arguments concerning conversation as i) a situated and distributed activity, ii) a "product" in perpetual construction, and iii) the amount of credence and belief we afford it. Finally, we will advocate for metaphorical tools that promote a more dynamic conceptualization of human thinking.

Conversational Styles and Misunderstanding in Cross-Sex Conversations in He’s Just Not That into You Movie

OpenAIRE

Ayu Nyoman Aryani

2017-01-01

Conversation is a social interaction among societies. In this case, gender differences in daily communication lead to men’s and women’s different point of views in performing styles of the conversations. Misunderstanding is likely to occur in crosssex conversations when the idea or thought are understood differently by men and women. This study was intended to analyze the use of conversational styles by men and women and also investigate the misunderstanding phenomena that happened in cross-s...

Fuel conversion of JRR-4 from HEU to LEU

International Nuclear Information System (INIS)

Ichikawa, Hiroki; Nakajima, Teruo

1997-01-01

Japanese JRR-4 (Japan Research Reactor No.4) is a pool type, light water moderated and cooled, ETR type fuel reactor used for Shielding experiments, isotope production, neutron activation analyses, Si doping, reactor students training. It acieved first criticality on January 28, 1965 with maximum thermal power 3.5MW. The standard core consistes of 20 Fuel elements, 7 control rods 5 Irradiation holes, neutron source, graphite reflectors. Available thermal flux is 7x1013 n/cm2/s. Within the RERTR program plans are made for core conversion from HEU to LEU

Conversational evidence in therapeutic dialogue.

Science.gov (United States)

Strong, Tom; Busch, Robbie; Couture, Shari

2008-07-01

Family therapists' participation in therapeutic dialogue with clients is typically informed by evidence of how such dialogue is developing. In this article, we propose that conversational evidence, the kind that can be empirically analyzed using discourse analyses, be considered a contribution to widening psychotherapy's evidence base. After some preliminaries about what we mean by conversational evidence, we provide a genealogy of evaluative practice in psychotherapy, and examine qualitative evaluation methods for their theoretical compatibilities with social constructionist approaches to family therapy. We then move on to examine the notion of accomplishment in therapeutic dialogue given how such accomplishments can be evaluated using conversation analysis. We conclude by considering a number of research and pedagogical implications we associate with conversational evidence.

Effective communication during difficult conversations.

Science.gov (United States)

Polito, Jacquelyn M

2013-06-01

A strong interest and need exist in the workplace today to master the skills of conducting difficult conversations. Theories and strategies abound, yet none seem to have found the magic formula with universal appeal and success. If it is such an uncomfortable skill to master is it better to avoid or initiate such conversations with employees? Best practices and evidence-based management guide us to the decision that quality improvement dictates effective communication, even when difficult. This brief paper will offer some suggestions for strategies to manage difficult conversations with employees. Mastering the skills of conducting difficult conversations is clearly important to keeping lines of communication open and productive. Successful communication skills may actually help to avert confrontation through employee engagement, commitment and appropriate corresponding behavior

5 CFR 536.303 - Geographic conversion.

Science.gov (United States)

2010-01-01

... after geographic conversion is the employee's existing payable rate of basic pay in effect immediately before the action. (b) Geographic conversion when a retained rate employee's official worksite is changed... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Geographic conversion. 536.303 Section...

Investigation of the structural, surface, optical and electrical properties of the Indium doped CuxO thin films deposited by a thermionic vacuum arc

Science.gov (United States)

Musaoğlu, Caner; Pat, Suat; Özen, Soner; Korkmaz, Şadan; Mohammadigharehbagh, Reza

2018-03-01

In this study, investigation of some physical properties of In-doped CuxO thin films onto amorphous glass substrates were done. The thin films were depsoied by thermionic vacuum arc technique (TVA). TVA technique gives a thin film with lower precursor impurity according to the other chemical and physical depsoition methods. The microstructural properties of the produced thin films was determined by x-ray diffraction device (XRD). The thickness values were measured as to be 30 nm and 60 nm, respectively. The miller indices of the thin films’ crystalline planes were determined as to be Cu (111), CuO (\\bar{1} 12), CuInO2 (107) and Cu2O (200), Cu (111), CuO (\\bar{1} 12), CuO (\\bar{2} 02), CuInO2 (015) for sample C1 and C2, respectively. The produced In-doped CuO thin films are in polycrystalline structure. The surface properties of produced In doped CuO thin films were determined by using an atomic force microscope (AFM) and field emission scanning electron microscope (FESEM) tools. The optical properties of the In doped CuO thin films were determined by UV–vis spectrophotometer, interferometer, and photoluminescence devices. p-type semiconductor thin film was obtained by TVA depsoition.

Storage Reliability Missile Materiel Program. Storage Reliability Summary Report. Volume 2. Electromechanical Devices

Science.gov (United States)

1978-02-01

ii•t, difforonc wit h ono data not’ hoV14. a nq I til i. It n 1.1 y Hho i~r fitltrevi rato, TIhil # da tai ou t W~AP i’eiwivod and th I’ll oeitnniciw...consideration. Wolfram, molybdenum, and carbon are able to sustain an arc without reaching their melting point (sufficient thermionic emission occurs at

24 CFR 972.109 - Conversion of developments.

Science.gov (United States)

2010-04-01

... writing whether it has approved the conversion plan. Units that are vacant or vacated on or after the... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Conversion of developments. 972.109... DEVELOPMENT CONVERSION OF PUBLIC HOUSING TO TENANT-BASED ASSISTANCE Required Conversion of Public Housing...

[Management of patients with conversion disorder].

Science.gov (United States)

Vermeulen, Marinus; Hoekstra, Jan; Kuipers-van Kooten, Mariëtte J; van der Linden, Els A M

2014-01-01

The symptoms of conversion disorder are not due to conscious simulation. There should be no doubt that the symptoms of conversion disorder are genuine, even if scans do not reveal any abnormalities. The management of patients with conversion disorder starts with an explanation of the diagnosis. The essence of this explanation is that patients first hear about what the diagnosis actually means and only after this about what they do not have. When explaining the diagnosis it is a good idea to use metaphors. The treatment of patients with conversion disorder is carried out together with a physical therapist. The collaboration of healthcare professionals who are involved in the treatment of a patient with conversion disorder should preferably be coordinated by the patient's general practitioner.

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 1: Coal-fired nocogeneration process boiler, section B

Science.gov (United States)

Knightly, W. F.

1980-01-01

About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. Computer generated reports of the fuel consumption and savings, capital costs, economics and emissions of the cogeneration energy conversion systems (ECS's) heat and power matched to the individual industrial processes are presented. National fuel and emissions savings are also reported for each ECS assuming it alone is implemented. Two nocogeneration base cases are included: coal fired and residual fired process boilers.

Program summaries for 1979: energy sciences programs

Energy Technology Data Exchange (ETDEWEB)

1979-12-01

This report describes the objectives of the various research programs being conducted by the Chemical Sciences, Metallurgy and Materials Science, and Process Science divisions of the BNL Dept. of Energy and Environment. Some of the more significant accomplishments during 1979 are also reported along with plans for 1980. Some of the topics under study include porphyrins, combustion, coal utilization, superconductors, semiconductors, coal, conversion, fluidized-bed combustion, polymers, etc. (DLC)

Carbon balances during land conversion in early bioenergy systems

Science.gov (United States)

Zenone, T.; Chen, J.; Gelfand, I.; Robertson, G. P.; Hamilton, S. K.

2012-12-01

In this study, we established a field experiment and deployed seven eddy-covariance towers to quantify the roles of land use change and the subsequent carbon (C) balances of three different bioenergy systems (corn, switchgrass, and mixed prairie species) that were developed from two historical land use types: monocultural grasslands dominated by smooth brome (Bromus inermis Leyss) and lands in the Conservation Reserve Program (CRP). Three CRP fields and three cropland fields were converted to soybean in 2009 (conversion year) before establishing the cellulosic biofuel cropping systems in 2010 (establishment year). A CRP perennial grassland site was kept undisturbed as a reference. Conversion of CRP to soybean induced net C emissions during the conversion year (134 -262 g C m-2 yr-1), while in the same year the net C balance at the CRP grassland reference was -35 g C m-2 yr-1 (i.e., net C sequestration). The establishment of switchgrass and mixed prairie induced a cumulative C balance of -113 g C m-2 (switchgrass from CRP), 250 g C m-2 (switchgrass from cropland), 706 g C m-2 (mixed prairie from CRP), and 59 g C m-2 (mixed prairie from cropland) over the three-year study period. The cumulative three-year C balance of corn converted from CRP and from cropland was -151 g C m-2 and -183 g C m-2, respectively. Eddy flux measurements during cellulosic biofuel crop establishment reveal annual changes in C balance that cannot be detected using conventional mass balance approaches. When end-use of harvested biomass was considered, the C balances for all studied systems, except the reference site, exhibited large C emissions ranging from 150 to 990 g C m-2 over the three-year conversion phase.

Energy conversion alternatives study

Science.gov (United States)

Shure, L. T.

1979-01-01

Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

[Hydroxylamine conversion by anammox enrichment].