WorldWideScience

Sample records for radioisotope current source

  1. A power conditioning system for radioisotope thermoelectric generator energy sources

    Science.gov (United States)

    Gillis, J. A., Jr.

    1974-01-01

    The use of radioisotope thermoelectric generators (RTG) as the primary source of energy in unmanned spacecraft is discussed. RTG output control, power conditioning system requirements, the electrical design, and circuit performance are also discussed.

  2. Environmental assessment for radioisotope heat source fuel processing and fabrication

    Energy Technology Data Exchange (ETDEWEB)

    1991-07-01

    DOE has prepared an Environmental Assessment (EA) for radioisotope heat source fuel processing and fabrication involving existing facilities at the Savannah River Site (SRS) near Aiken, South Carolina and the Los Alamos National Laboratory (LANL) near Los Alamos, New Mexico. The proposed action is needed to provide Radioisotope Thermoelectric Generators (RTG) to support the National Aeronautics and Space Administration's (NASA) CRAF and Cassini Missions. Based on the analysis in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, an Environmental Impact Statement is not required. 30 refs., 5 figs.

  3. Radioisotope instruments

    CERN Document Server

    Cameron, J F; Silverleaf, D J

    1971-01-01

    International Series of Monographs in Nuclear Energy, Volume 107: Radioisotope Instruments, Part 1 focuses on the design and applications of instruments based on the radiation released by radioactive substances. The book first offers information on the physical basis of radioisotope instruments; technical and economic advantages of radioisotope instruments; and radiation hazard. The manuscript then discusses commercial radioisotope instruments, including radiation sources and detectors, computing and control units, and measuring heads. The text describes the applications of radioisotop

  4. Optimization Design and Simulation of a Multi-Source Energy Harvester Based on Solar and Radioisotope Energy Sources

    Directory of Open Access Journals (Sweden)

    Hao Li

    2016-12-01

    Full Text Available A novel multi-source energy harvester based on solar and radioisotope energy sources is designed and simulated in this work. We established the calculation formulas for the short-circuit current and open-circuit voltage, and then studied and analyzed the optimization thickness of the semiconductor, doping concentration, and junction depth with simulation of the transport process of β particles in a semiconductor material using the Monte Carlo simulation program MCNP (version 5, Radiation Safety Information Computational Center, Oak Ridge, TN, USA. In order to improve the efficiency of converting solar light energy into electric power, we adopted PC1D (version 5.9, University of New South Wales, Sydney, Australia to optimize the parameters, and selected the best parameters for converting both the radioisotope energy and solar energy into electricity. The results concluded that the best parameters for the multi-source energy harvester are as follows: Na is 1 × 1019 cm−3, Nd is 3.8 × 1016 cm−3, a PN junction depth of 0.5 μm (using the 147Pm radioisotope source, and so on. Under these parameters, the proposed harvester can achieve a conversion efficiency of 5.05% for the 147Pm radioisotope source (with the activity of 9.25 × 108 Bq and 20.8% for solar light radiation (AM1.5. Such a design and parameters are valuable for some unique micro-power fields, such as applications in space, isolated terrestrial applications, and smart dust in battlefields.

  5. ADVANCED RADIOISOTOPE HEAT SOURCE AND PROPULSION SYSTEMS FOR PLANETARY EXPLORATION

    Energy Technology Data Exchange (ETDEWEB)

    R. C. O' Brien; S. D. Howe; J. E. Werner

    2010-09-01

    The exploration of planetary surfaces and atmospheres may be enhanced by increasing the range and mobility of a science platform. Fundamentally, power production and availability of resources are limiting factors that must be considered for all science and exploration missions. A novel power and propulsion system is considered and discussed with reference to a long-range Mars surface exploration mission with in-situ resource utilization. Significance to applications such as sample return missions is also considered. Key material selections for radioisotope encapsulation techniques are presented.

  6. An Adjunct Galilean Satellite Orbiter Using a Small Radioisotope Power Source

    Science.gov (United States)

    Abelson, Robert Dean; Randolph, J.; Alkalai, L.; Collins, D.; Moore, W.

    2005-01-01

    This is a conceptual mission study intended to demonstrate the range of possible missions and applications that could be enabled were a new generation of Small Radioisotope Power Systems to be developed by NASA and DOE. While such systems are currently being considered by NASA and DOE, they do not currently exist. This study is one of several small RPS-enabled mission concepts that were studied and presented in the NASA/JPL document "Enabling Exploration with Small Radioisotope Power Systems" available at: http://solarsystem.nasa.gov/multimedia/download-detail.cfm?DL_ID=82

  7. A compact and high current FFAG for the production of radioisotopes for medical application

    CERN Document Server

    Bruton, David; Edgecock, Rob; Seviour, Rebecca; Johnstone, Carol

    2017-01-01

    A low energy Fixed Field Alternating Gradient(FFAG)accelerator has been designed for the production of radioisotopes. Tracking studies have been conducted using the OPAL code, including the effects of space charge. Radioisotopes have a wide range of uses in medicine, and recent disruption to the supply chain has seen a renewed effort to find alternative isotopes and production methods. The design features separate sector magnets with non-scaling, non-linear field gradients but without the counter bends commonly found in FFAG’s. The machine is isochronous at the level of 0.3% up to at least 28MeV and hence able to operate in Continuous Wave (CW) mode. Both protons and helium ions can be used with this design and it has been demonstrated that proton beams with currents of up to 20 mA can be accelerated. An interesting option for the production of radioisotopes is the use of a thin internal target. We have shown that this design has large acceptance, ideal for allowing the beam to be recirculated through t...

  8. Integration of Americium Heat Source into the Advanced Stirling Radioisotope Generator

    Science.gov (United States)

    Schulze, Erich; Quinn, Richard

    2014-08-01

    The Lockheed Martin developed Advanced Stirling Radioisotope Generator (ASRG) design uses similar technology as proposed for the European Space Agency (ESA) Radioisotope Power System (RPS) development program but different isotopes. The RPS uses americium, 241Am isotope, while the ASRG uses plutonium, 238Pu isotope. The 238Pu isotope provides four times greater thermal output per kilogram than the 241Am isotope. Lockheed Martin performed an internally funded feasibility assessment that determined integration of a 241Am fueled heat source into the ASRG is achievable with no changes to ASRG technology and only structural and volumetric design considerations required. Lockheed Martin is interested in developing collaborative partnerships with the United Kingdom (UK) for the ESA RPS development program.

  9. Integration of Radioisotope Heat Source with Stirling Engine and Cooler for Venus Internal-Structure Mission

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred

    1993-10-01

    The primary mission goal is to perform long-term seismic measurements on Venus, to study its largely unknown internal structure. The principal problem is that most payload components cannot long survive Venus's harsh environment, 90 bars at 500 degrees C. To meet the mission life goal, such components must be protected by a refrigerated payload bay. JPL Investigators have proposed a mission concept employing a lander with a spherical payload bay cooled to 25 degrees C by a Stirling cooler powered by a radioisotope-heated Sitrling engine. To support JPL's mission study, NASA/Lewis and MTI have proposed a conceptual design for a hydraulically coupled Stirling engine and cooler, and Fairchild Space - with support of the Department of Energy - has proposed a design and integration scheme for a suitable radioisotope heat source. The key integration problem is to devise a simple, light-weight, and reliable scheme for forcing the radioisotope decay heat to flow through the Stirling engine during operation on Venus, but to reject that heat to the external environment when the Stirling engine and cooler are not operating (e.g., during the cruise phase, when the landers are surrounded by heat shields needed for protection during subsequent entry into the Venusian atmosphere.) A design and integration scheme for achieving these goals, together with results of detailed thermal analyses, are described in this paper. There are 7 copies in the file.

  10. Current status of the production and research of radioisotopes in JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hidetake [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Sekine, Toshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-10-01

    Status of the radioisotope production and application in Japan is described, emphasizing that of reactor-produced radioisotopes for medicine. Some new application of reactor-produced radioisotopes to therapy are discussed together with those of positron emitters for medicine and plant physiology. (author)

  11. Power from Radioisotopes (Rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R; Mead, Robert L

    1971-01-01

    This booklet discusses Systems for Nuclear Auxiliary Power (SNAP), called isotope power generators, that are based on using heat from the decay of radioisotopes to produce electricity. These are the SNAP systems with odd-numbered designators. The basics of radioisotope thermoelectric generators (RTGs) are discussed and their uses as power sources in space exploration and on earth are described. Various radioisotope heat sources are discussed and a table of RTGs built under the SNAP program listing their uses, electrical power, weight, the radioisotope used, the radioisotope's half-life, and the generator life is given.

  12. Current Source Logic Gate

    Science.gov (United States)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2017-01-01

    A current source logic gate with depletion mode field effect transistor ("FET") transistors and resistors may include a current source, a current steering switch input stage, and a resistor divider level shifting output stage. The current source may include a transistor and a current source resistor. The current steering switch input stage may include a transistor to steer current to set an output stage bias point depending on an input logic signal state. The resistor divider level shifting output stage may include a first resistor and a second resistor to set the output stage point and produce valid output logic signal states. The transistor of the current steering switch input stage may function as a switch to provide at least two operating points.

  13. Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator Programs

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, D. M.; Miller, G. D.; Bohne, W. A.

    1995-03-16

    The purpose of this document is to serve as the Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator (HS/RTG) programs performed at EG&G Mound Applied Technologies. As such, it identifies and describes the systems and activities in place to support the requirements contained in DOE Order 5700.6C as reflected in MD-10334, Mound Quality Policy and Responsibilities and the DOE/RPSD supplement, OSA/PQAR-1, Programmatic Quality Assurance Requirements for Space and Terrestrial Nuclear Power Systems. Unique program requirements, including additions, modifications, and exceptions to these quality requirements, are contained in the appendices of this plan. Additional appendices will be added as new programs and activities are added to Mound's HS/RTG mission assignment.

  14. Radioisotope Production for Medical and Physics Applications

    Science.gov (United States)

    Mausner, Leonard

    2012-10-01

    Radioisotopes are critical to the science and technology base of the US. Discoveries and applications made as a result of the availability of radioisotopes span widely from medicine, biology, physics, chemistry and homeland security. The clinical use of radioisotopes for medical diagnosis is the largest sector of use, with about 16 million procedures a year in the US. The use of ^99Mo/^99mTc generator and ^18F make up the majority, but ^201Tl, ^123I, ^111In, and ^67Ga are also used routinely to perform imaging of organ function. Application of radioisotopes for therapy is dominated by use of ^131I for thyroid malignancies, ^90Y for some solid tumors, and ^89Sr for bone cancer, but production of several more exotic species such as ^225Ac and ^211At are of significant current research interest. In physics ^225Ra is of interest for CP violation studies, and the actinides ^242Am, ^249Bk, and ^254Es are needed as targets for experiments to create superheavy elements. Large amounts of ^252Cf are needed as a fission source for the CARIBU experiment at ANL. The process of radioisotope production is multidisciplinary. Nuclear physics input based on nuclear reaction excitation function data is needed to choose an optimum target/projectile in order to maximize desired isotope production and minimize unwanted byproducts. Mechanical engineering is needed to address issues of target heating, induced mechanical stress and material compatibility of target and claddings. Radiochemists are involved as well since chemical separation to purify the desired final radioisotope product from the bulk target and impurities is also usually necessary. Most neutron rich species are produced at a few government and university reactors. Other radioisotopes are produced in cyclotrons in the commercial sector, university/hospital based facilities, and larger devices at the DOE labs. The landscape of US facilities, the techniques involved, and current supply challenges will be reviewed.

  15. The design of a source to simulate the gamma-ray spectrum emitted by a radioisotope thermoelectric generator

    Science.gov (United States)

    Reier, M.

    1972-01-01

    A simulated source was designed to duplicate the gamma spectrum of a uniform cylindrical 2200-watt Pu02 radioisotope thermoelectric generator containing 81% Pu-238 and 1.2 ppm Pu-236. Gamma rays from the decay of Pu-238, Am-241, Pu-239, and the 0-18(alpha,n)Ne-21 reaction were catalogued in broad energy groups. Two 46- and one 22-mc Th-228 sources provided simulation at various times in the life of the fuel capsule up to 18 years, which covers the time span of an outer planet mission. Emission from Th-228 represents the overwhelming contribution of the gamma spectrum after the first few years. The sources, in the form of 13-inch rods, were placed in a concentric hole in a cylinder of depleted uranium, which provided shielding equivalent to the self-shielding of the fuel capsule. The thickness of the U-238 cylinder (0.55cm) was determined by Monte Carlo calculations to insure that the spectrum emerging from the simulated source matched that of the fuel capsule.

  16. GPHS-RTG system explosion test direct course experiment 5000. [General Purpose Heat Source-Radioisotope Thermoelectric Generator

    Energy Technology Data Exchange (ETDEWEB)

    1984-03-01

    The General Purpose Heat Source-Radioisotope Thermoelectric Generator (GPHS-RTG) has been designed and is being built to provide electrical power for spacecrafts to be launched on the Space Shuttle. The objective of the RTG System Explosion Test was to expose a mock-up of the GPHS-RTG with a simulated heat source to the overpressure and impulse representative of a potential upper magnitude explosion of the Space Shuttle. The test was designed so that the heat source module would experience an overpressure at which the survival of the fuel element cladding would be expected to be marginal. Thus, the mock-up was placed where the predicted incident overpressure would be 1300 psi. The mock-up was mounted in an orientation representative of the launch configuration on the spacecraft to be used on the NASA Galileo Mission. The incident overpressure measured was in the range of 1400 to 2100 psi. The mock-up and simulated heat source were destroyed and only very small fragments were recovered. This damage is believed to have resulted from a combination of the overpressure and impact by very high velocity fragments from the ANFO sphere. Post-test analysis indicated that extreme working of the iridium clad material occurred, indicative of intensive impulsive loading on the metal.

  17. Radioisotope Power System Pool Concept

    Science.gov (United States)

    Rusick, Jeffrey J.; Bolotin, Gary S.

    2015-01-01

    Advanced Radioisotope Power Systems (RPS) for NASA deep space science missions have historically used static thermoelectric-based designs because they are highly reliable, and their radioisotope heat sources can be passively cooled throughout the mission life cycle. Recently, a significant effort to develop a dynamic RPS, the Advanced Stirling Radioisotope Generator (ASRG), was conducted by NASA and the Department of Energy, because Stirling based designs offer energy conversion efficiencies four times higher than heritage thermoelectric designs; and the efficiency would proportionately reduce the amount of radioisotope fuel needed for the same power output. However, the long term reliability of a Stirling based design is a concern compared to thermoelectric designs, because for certain Stirling system architectures the radioisotope heat sources must be actively cooled via the dynamic operation of Stirling converters throughout the mission life cycle. To address this reliability concern, a new dynamic Stirling cycle RPS architecture is proposed called the RPS Pool Concept.

  18. Development of a method for multielemental determination in water by EDXRF with radioisotopic source of {sup 238}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, C.; Estévez, J.; Montero, A.; Pupo, I.; Herrero, Z.; Leyva, D.; Arteche, J.; Varcárcel, L. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), (Cuba); Van Espen, P. [University of Amberes, (Belgium); Santos Júnior, J. A. dos, E-mail: cserrano@cedaen.edu.cu [Universidade Federal de Pernambuco (UFPE), Recife (Brazil)

    2017-07-01

    A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of {sup 238}Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidine dithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of {sup 238}Pu instead of {sup 109}Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L). (author)

  19. Modulation of Current Source Inverter

    Directory of Open Access Journals (Sweden)

    Golam Reza Arab Markadeh

    2011-04-01

    Full Text Available Direct torque control with Current Source Inverter (CSI instead of voltage source inverter is so appropriate because of determining the torque of induction motor with machine current and air gap flux. In addition, Space-Vector Modulation (SVM is a more proper method for CSI because of low order harmonics reduction, lower switching frequency and easier implementation. This paper introduces the SVM method for CSI and uses the proposed inverter for vector control of an induction motor. The simulation results illustrate fast dynamic response and desirable torque and speed output. Fast and accurate response to changes of speed and load torque reference completely proves the prominence of this method.

  20. Projection of needs for gamma radiation sources and other radioisotopes and assessment of alternatives for providing radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Ross, W.A.; Jensen, G.A.; Clark, L.L.; Eakin, D.E.; Jarrett, J.H.; Katayama, Y.B.; McKee, R.W.; Morgan, L.G.; Nealey, S.M.; Platt, A.M.; Tingey, G.L.

    1989-06-01

    Pacific Northwest Laboratory reviewed the projected uses and demands for a variety of nuclear byproducts. Because the major large-scale near-term demand is for gamma irradiation sources, this report concentrates on the needs for gamma sources and evaluates the options for providing the needed material. Projections of possible growth in the irradiation treatment industry indicate that there will be a need for 180 to 320 MCi of /sup 60/Co (including /sup 137/Cs equivalent) in service in the year 2000. The largest current and projected use of gamma irradiation is for the sterilization of medical devices and disposable medical supplies. Currently, 40% of US disposable medical products are treated by irradiation, and within 10 years it is expected that 90% will be treated in this manner. Irradiation treatment of food for destruction of pathogens or parasites, disinfestation, or extension of allowable storage periods is estimated to require an active inventory of 75 MCi of /sup 60/Co-equivalent gamma source in about a decade. 90 refs., 7 figs., 25 tabs.

  1. Elemental analysis of a concrete sample by capture gamma rays with a radioisotope neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Collico Savio, D.L. [Ciudad Universitaria, Buenos Aires (Argentina). Lab. de Fisica Nuclear; Mariscotti, M.A.J. [Ciudad Universitaria, Buenos Aires (Argentina). Lab. de Fisica Nuclear; Ribeiro Guevara, S. [Laboratorio Analisis por Activacion Neutronica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)

    1995-03-15

    Gamma radiation from capture of neutrons in concrete has been studied in the energy region from 0.3 to 10.5 MeV with a HPGe spectrometer and an AmBe neutron source. A careful analysis of the Fe, Si, Ca, and Cl peak intensities made it possible to determine their relative concentrations in the sample. A comparison has been made between this nuclear method and chemical techniques, resulting in good agreement. The employment of these nuclear reactions constitutes a promising technique for the bulk analysis of samples in the concrete industry, because of its nondestructive and in-situ nature. ((orig.)).

  2. Radioisotopes for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Carr, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Radiopharmaceuticals Division

    1998-03-01

    For more than 3 decades, the Australian Nuclear Science and Technology Organisation has been the country`s main supplier of radioisotopes for medical applications. The use of radioisotopes in medicine has revolutionised the diagnosis, management and treatment of many serious diseases such as cancer, heart disease and stroke. It is also beginning to play a key role in neurological disorders such as Parkinson and Alzheimers disease and epilepsy. More recently there has been considerable growth in the application of nuclear medicine to treat sport-related injuries - especially wrist, ankle and knees where more common techniques do not always enable accurate diagnosis. Australia is a recognised leader in nuclear medicine. This can be partially attributed to the close relationship between ANSTO and the medical community in providing opportunities to develop and evaluate new agents to support more effective patient care. A list of commercial isotopes produced in the reactor or the cyclotron and used in medical applications is given. Nuclear medicine plays an important role in the clinical environment and the timely supply of radioisotopes is a key element. ANSTO will continue to be the premier supplier of currently available and developing isotopes to support the health and well being of the Australian community 2 tabs., 1 fig.

  3. High current polarized proton sources

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, J.G.

    1988-01-01

    Polarized proton sources are now being used more frequently on linacs. In pulsed operation up to 10 mA of /rvec H//sup +/ and 0.4 mA of /rvec H//sup /minus// have been produced. The present status of these sources, and developments to reach even higher intensities, are reviewed. 39 refs., 1 tab.

  4. BEST medical radioisotope production cyclotrons

    Energy Technology Data Exchange (ETDEWEB)

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R. [Best Cyclotron Systems Inc., 7-8765 Ash Street, Vancouver, British Columbia, V6P 6T3 (Canada); Gelbart, W. Z. [Advanced System Designs Inc., 5295 Bear Bay Road, Garden Bay, BC, V0N 1S1 (Canada)

    2013-04-19

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 {mu}A to 1000 {mu}A, depending on the cyclotron energy and application.

  5. Radioisotope Power Supply Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Between 1998 and 2003, Hi-Z Technology developed and built a 40 mW radioisotope power supply (RPS) that used a 1 watt radioisotope heater unit (RHU) as the energy...

  6. Current source design for electrical impedance tomography.

    Science.gov (United States)

    Ross, Alexander S; Saulnier, G J; Newell, J C; Isaacson, D

    2003-05-01

    Questions regarding the feasibility of using electrical impedance tomography (EIT) to detect breast cancer may be answered by building a sufficiently precise multiple frequency EIT instrument. Current sources are desirable for this application, yet no current source designs have been reported that have the required precision at the multiple frequencies needed. We have designed an EIT current source using an enhanced Howland topology in parallel with a generalized impedance converter (GIC). This combination allows for nearly independent adjustment of output resistance and output capacitance, resulting in simulated output impedances in excess of 2 Gohms between 100 Hz and 1 MHz. In this paper, the theoretical operation of this current source is explained, and experimental results demonstrate the feasibility of creating a high precision, multiple frequency, capacitance compensated current source for EIT applications.

  7. Radioisotope electric propulsion (REP): A near-term approach to nuclear propulsion

    Science.gov (United States)

    Schmidt, George R.; Manzella, David H.; Kamhawi, Hani; Kremic, Tibor; Oleson, Steven R.; Dankanich, John W.; Dudzinski, Leonard A.

    2010-02-01

    Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.

  8. Efficient, Long-Lived Radioisotope Power Generator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation Monitoring Devices, Inc., (RMD) proposes to develop an alternative very long term, radioisotope power source with thermoelectric power conversion with...

  9. Stability analysis of direct current control in current source rectifier

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...... of dc link is developed to identify the control plants of grid ac current control and dc current control. Analysis on the poles and zeros under dq frame is carried out. Base on this model, it turns out that the phase lag caused by the time delay can stabilized the grid ac current control while reduces...... the stable region for dc current control. Simulation and experimental results are presented to validate the theoretical analysis....

  10. Production and utilization of radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Toshiaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Matsuoka, Hiromitsu

    1999-03-01

    A plan of developing radioisotopes with a high power proton accelerator of the Neutron Science Project is presented. The status of production and utilization of radioisotopes in Japan is briefly discussed. The radioisotopes to be produced for biomedical use are discussed together with the facility for production of those radioisotopes and for research with the products. (author)

  11. Economical Radioisotope Power Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Almost all robotic space exploration missions and all Apollo missions to the moon used Radioisotopic Thermoelectric Generators (RTGs) to provide electrical power to...

  12. Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kronberger, M., E-mail: matthias.kronberger@gmx.at [European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); Department of Physics, University of Jyväskylä, Survontie 9, FI-40014 (Finland); Gottberg, A. [European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); Instituto de Estructura de la Materia CSIC, E28006 Madrid (Spain); Mendonca, T.M. [European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); IFIMUP and IN – Institute of Nanosciences and Nanotechnologies, University of Porto, Rua do Campo Alegre 687, PT-4169-007 (Portugal); Ramos, J.P. [European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); Ecole Polytechnique Federale de Lausanne, CH-1015 (Switzerland); Seiffert, C.; Suominen, P.; Stora, T. [European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland)

    2013-12-15

    Highlights: • We present a novel radioactive ion source concept for nuclear physics experiments. • Molecular sideband beams are produced by an RF discharge in a magnetized plasma. • Ionization efficiencies of 2.5% and 4% were measured for CO{sup +} and Ar, respectively. • Using a HfO{sub 2} fibre target, 17-CO{sup +} was produced for the first time at ISOLDE. • Up to 50 × gain was achieved by using a nanostructured CaO target and He as buffer gas. -- Abstract: In order to account for the increasing demand for strong molecular beams for nuclear physics experiments at ISOLDE, a new radioactive ion source concept based on an RF discharge in a magnetized plasma was developed at CERN. Experimental studies at the ISOLDE offline separator show that the optimum conditions for CO{sup +} and CO{sub 2}{sup +} ion production are given when the ion source is operated with He plasma, in line with expectations based on their electron impact ionization cross-sections. At optimum tuning, ionization efficiencies of 2.5% and 4% were measured for CO{sup +} and Ar{sup +}, respectively. The capability of the Helicon ion source prototype for ISOL operation was evaluated during two online runs at the General Purpose Separator of CERN-ISOLDE, yielding the first observation of {sup 17}CO{sup +} with a HfO{sub 2} fibre target, and a more than 50-fold enhancement of the {sup 10}CO{sup +} and {sup 11}CO{sup +} yields with a nanostructured CaO target and an upgraded ion source prototype.

  13. Markets for reactor-produced non-fission radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, R.G.

    1995-01-01

    Current market segments for reactor produced radioisotopes are developed and reported from a review of current literature. Specific radioisotopes studied in is report are the primarily selected from those with major medical or industrial markets, or those expected to have strongly emerging markets. Relative market sizes are indicated. Special emphasis is given to those radioisotopes that are best matched to production in high flux reactors such as the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory or the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory. A general bibliography of medical and industrial radioisotope applications, trends, and historical notes is included.

  14. Productivity of a nuclear chemical reactor with gamma radioisotopic sources; Rendimiento de un reactor quimico-nuclear con fuentes radioisotopicas gamma

    Energy Technology Data Exchange (ETDEWEB)

    Anguis T, C

    1975-07-01

    According to an established mathematical model of successive Compton interaction processes the made calculations for major distances are extended checking the acceptability of the spheric geometry model for the experimental data for radioisotopic sources of Co-60 and Cs-137. Parameters such as the increasing factor and the absorbed dose served as comparative base. calculations for the case of a punctual source succession inside a determined volume cylinder are made to obtain the total dose, the deposited energy by each photons energetic group and the total absorbed energy inside the reactor. Varying adequately the height/radius relation for different cylinders, the distinct energy depositions are compared in each one of them once a time standardized toward a standard value of energy emitted by the reactor volume. A relation between the quantity of deposited energy in each point of the reactor and the conversion values of chemical species is established. They are induced by electromagnetic radiation and that are reported as ''G'' in the scientific literature (number of molecules formed or disappeared by each 100 e.v. of energy). Once obtained the molecular performance inside the reactor for each type of geometry, it is optimized the height/radius relation according to the maximum production of molecules by unity of time. It is completed a bibliographical review of ''G'' values reported by different types of aqueous solutions with the purpose to determine the maximum performance of molecular hydrogen as a function of pH of the solution and of the used type of solute among other factors. Calculations for the ethyl bromide production as an example of one of the industrial processes which actually work using the gamma radiation as reactions inductor are realized. (Author)

  15. Vitrified chemically bonded phosphate ceramics for immobilization of radioisotopes

    Science.gov (United States)

    Wagh, Arun S.

    2016-04-05

    A method of immobilizing a radioisotope and vitrified chemically bonded phosphate ceramic (CBPC) articles formed by the method are described. The method comprises combining a radioisotope-containing material, MgO, a source of phosphate, and optionally, a reducing agent, in water at a temperature of less than 100.degree. C. to form a slurry; curing the slurry to form a solid intermediate CBPC article comprising the radioisotope therefrom; comminuting the intermediate CBPC article, mixing the comminuted material with glass frits, and heating the mixture at a temperature in the range of about 900 to about 1500.degree. C. to form a vitrified CBPC article comprising the radioisotope immobilized therein.

  16. Radioisotope Thermophotovoltaic (RTPV) Generator and Its Application to the Pluto Fast Flyby Mission

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred; Mukunda, Meera; Or, Chuen T; Kumar, Vasanth; Summers, G.

    1994-01-16

    This paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator. Instead of conducting a generic study, it was decided to focus the design by directing it at a specific space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a one-year post-encounter cruise. Because of Pluto's long distance from the sun (30-50 A.U.) and the mission's large energy demand, JPL has baselined the use of a radioisotope power system for the PFF spacecraft. The chief advantage of Radioisotope Thermophotovoltaic (RTPV) power systems over current Radioisotope Thermoelectric Generators (RTGs) is their much higher conversion efficiency, which greatly reduces the mass and cost of the required radioisotope heat source. Those attributes are particularly important for the PFF mission, which - like all NASA missions under current consideration - is severely mass- and cost-limited. The paper describes the design of the radioisotope heat source, the thermophotovoltaic converter, and the heat rejection system; and presents the results of the thermal, electrical, and structural analysis and the design optimization of the integrated RTPV system. It briefly summarizes the RTPV system's current technology status, and lists a number of factors that my greatly reduce the need for long-term tests to demonstrate generator lifetime. Our analytical results show very substantial performance improvements over an RTG designed for the same mission, and suggest that the RTPV generator, when developed by DOE and/or NASA, would be quite valuable not only for the PFF mission but also for other future missions requiring small, long

  17. Planning For Multiple NASA Missions With Use Of Enabling Radioisotope Power

    Energy Technology Data Exchange (ETDEWEB)

    S.G. Johnson; K.L. Lively; C.C. Dwight

    2013-02-01

    Since the early 1960’s the Department of Energy (DOE) and its predecessor agencies have provided radioisotope power systems (RPS) to NASA as an enabling technology for deep space and various planetary missions. They provide reliable power in situations where solar and/or battery power sources are either untenable or would place an undue mass burden on the mission. In the modern era of the past twenty years there has been no time that multiple missions have been considered for launching from Kennedy Space Center (KSC) during the same year. The closest proximity of missions that involved radioisotope power systems would be that of Galileo (October 1989) and Ulysses (October 1990). The closest that involved radioisotope heater units would be the small rovers Spirit and Opportunity (May and July 2003) used in the Mars Exploration Rovers (MER) mission. It can be argued that the rovers sent to Mars in 2003 were essentially a special case since they staged in the same facility and used a pair of small launch vehicles (Delta II). This paper examines constraints on the frequency of use of radioisotope power systems with regard to launching them from Kennedy Space Center using currently available launch vehicles. This knowledge may be useful as NASA plans for its future deep space or planetary missions where radioisotope power systems are used as an enabling technology. Previous descriptions have focused on single mission chronologies and not analyzed the timelines with an emphasis on multiple missions.

  18. Radioisotopes in Industry

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Philip S. [Oak Ridge National Laboratory; Fuccillo, Jr., Domenic A. [Oak Ridge National Laboratory; Gerrard, Martha W. [Oak Ridge National Laboratory; Lafferty, Jr., Robert H. [Oak Ridge National Laboratory

    1967-05-01

    Radioisotopes, man-made radioactive elements, are used in industry primarily for measuring, testing and processing. How and why they are useful is the subject of this booklet. The booklet discusses their origin, their properties, their uses, and how they may be used in the future.

  19. NASA's Radioisotope Power Systems Program Status

    Science.gov (United States)

    Dudzinski, Leonard A.; Hamley, John A.; McCallum, Peter W.; Sutliff, Thomas J.; Zakrajsek, June F.

    2013-01-01

    NASA's Radioisotope Power Systems (RPS) Program began formal implementation in December 2010. The RPS Program's goal is to make available RPS for the exploration of the solar system in environments where conventional solar or chemical power generation is impractical or impossible to meet mission needs. To meet this goal, the RPS Program manages investments in RPS system development and RPS technologies. The current keystone of the RPS Program is the development of the Advanced Stirling Radioisotope Generator (ASRG). This generator will be about four times more efficient than the more traditional thermoelectric generators, while providing a similar amount of power. This paper provides the status of the RPS Program and its related projects. Opportunities for RPS generator development and targeted research into RPS component performance enhancements, as well as constraints dealing with the supply of radioisotope fuel, are also discussed in the context of the next ten years of planetary science mission plans.

  20. The radioisotope complex project “RIC-80” at the Petersburg Nuclear Physics Institute

    Energy Technology Data Exchange (ETDEWEB)

    Panteleev, V. N., E-mail: vnp@pnpi.spb.ru; Barzakh, A. E.; Batist, L. Kh.; Fedorov, D. V.; Ivanov, V. S.; Moroz, F. V.; Molkanov, P. L.; Orlov, S. Yu.; Volkov, Yu. M. [NRC “Kurchatov Institute” PNPI, 188300 Gatchina (Russian Federation)

    2015-12-15

    The high current cyclotron C-80 capable of producing 40-80 MeV proton beams with a current of up to 200 μA has been constructed at Petersburg Nuclear Physics Institute. One of the main goals of the C-80 is the production of a wide spectrum of medical radionuclides for diagnostics and therapy. The project development of the radioisotope complex RIC-80 (radioisotopes at the cyclotron C-80) at the beam of C-80 has been completed. The RIC-80 complex is briefly discussed in this paper. The combination of the mass-separator with the target-ion source device, available at one of the new target stations for on-line or semi on-line production of a high purity separated radioisotopes, is explored in greater detail. The results of target and ion source tests for a mass-separator method for the production of high purity radioisotopes {sup 82}Sr and {sup 223,224}Ra are also presented.

  1. The radioisotope complex project "RIC-80" at the Petersburg Nuclear Physics Institute.

    Science.gov (United States)

    Panteleev, V N; Barzakh, A E; Batist, L Kh; Fedorov, D V; Ivanov, V S; Moroz, F V; Molkanov, P L; Orlov, S Yu; Volkov, Yu M

    2015-12-01

    The high current cyclotron C-80 capable of producing 40-80 MeV proton beams with a current of up to 200 μA has been constructed at Petersburg Nuclear Physics Institute. One of the main goals of the C-80 is the production of a wide spectrum of medical radionuclides for diagnostics and therapy. The project development of the radioisotope complex RIC-80 (radioisotopes at the cyclotron C-80) at the beam of C-80 has been completed. The RIC-80 complex is briefly discussed in this paper. The combination of the mass-separator with the target-ion source device, available at one of the new target stations for on-line or semi on-line production of a high purity separated radioisotopes, is explored in greater detail. The results of target and ion source tests for a mass-separator method for the production of high purity radioisotopes (82)Sr and (223,224)Ra are also presented.

  2. Three Microwave Frequency Dividers Using Current Source/Sink and Modified Current Source Inverters

    Directory of Open Access Journals (Sweden)

    Gautham S. Harinarayan

    2013-01-01

    Full Text Available In a preceding paper Carlos E. Saavedra, 2005, established that frequency division can be achieved with the use of inverter rings and transmission gates. In this paper, we suggest three modified circuits which obtain the similar function, namely, using Current Sink Inverter, Current Source Inverter, and Modified Current Source Inverter. The performances of the proposed circuits are examined using Cadence and the model parameters of a 45 nm CMOS process. The simulation results of the three circuits are presented and are compared. We also present the results of a simple but effective novel technique to reduce clock skew between real and complementary clock signals and the corresponding improvement achieved in maximum frequency of operation. One of the proposed circuits can operate at up to 8.2 GHz input while performing a divide-by-4 operation.

  3. Taming Highly Charged Radioisotopes

    Science.gov (United States)

    Chowdhury, Usman; Eberhardt, Benjamin; Jang, Fuluni; Schultz, Brad; Simon, Vanessa; Delheij, Paul; Dilling, Jens; Gwinner, Gerald

    2012-10-01

    The precise and accurate mass of short-lived radioisotopes is a very important parameter in physics. Contribution to the improvement of nuclear models, metrological standard fixing and tests of the unitarity of the Caibbibo-Kobayashi-Maskawa (CKM) matrix are a few examples where the mass value plays a major role. TRIUMF's ion trap for atomic and nuclear physics (TITAN) is a unique facility of three online ion traps that enables the mass measurement of short-lived isotopes with high precision (˜10-8). At present TITAN's electron beam ion trap (EBIT) increases the charge state to increase the precision, but there is no facility to significantly reduce the energy spread introduced by the charge breeding process. The precision of the measured mass of radioisotopes is linearly dependent on the charge state while the energy spread of the charged radioisotopes affects the precision adversely. To boost the precision level of mass measurement at TITAN without loosing too many ions, a cooler Penning trap (CPET) is being developed. CPET is designed to use either positively (proton) or negatively (electron) charged particles to reduce the energy spread via sympathetic cooling. Off-line setup of CPET is complete. Details of the working principles and updates are presented

  4. ECR ion source for high current linac

    CERN Document Server

    Cui Bao Qun; Jiang Wei; LiLiQiang; WangRongWen

    2002-01-01

    An intense ECR ion source for ADS (accelerator driven sub-critical system) is described. Two configurations of the source has been developed and tested. 100 mA hydrogen beam has been extracted from the ion source at 30 keV, the proton ratio is greater than 85%, estimated emittance is 0.11 pi mm centre dot mrad, the maximum extracted beam density is 340 mA/cm sup 2 . A 100 hours reliability test of the source is also described

  5. Radioisotopes in management of metastatic prostate cancer

    Directory of Open Access Journals (Sweden)

    Amar Raval

    2016-01-01

    Full Text Available Introduction: Metastatic prostate cancer continues to be a leading cause of morbidity and mortality in men with prostate cancer. Over the last decade, the treatment landscape for patients with castrate-resistant disease has drastically changed, with several novel agents demonstrating an improvement in overall survival in large, multi-institutional randomized trials. Traditional treatment with radioisotopes has largely been in the palliative setting. However, the first in class radiopharmaceutical radium-223 has emerged as the only bone-directed treatment option demonstrating an improvement in overall survival. Methods: Medline publications from 1990 to 2016 were searched and reviewed to assess the use of currently approved radioisotopes in the management of prostate cancer including emerging data regarding integration with novel systemic therapies. New positron emission tomography-based radiotracers for advanced molecular imaging of prostate cancer were also queried. Results: Radioisotopes play a crucial role in the diagnosis and treatment of prostate cancer in the definitive and metastatic setting. Molecular imaging of prostate cancer and theranostics are currently being investigated in the clinical arena. Conclusions: The use of modern radioisotopes in selected patients with mCRPC is associated with improvements in overall survival, pain control, and quality of life.

  6. Planetary Protection Concerns During Pre-Launch Radioisotope Power System Final Integration Activities

    Science.gov (United States)

    Chen, Fei; McKay, Terri; Spry, James A.; Colozza, Anthony J.; DiStefano, Salvador

    2012-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is a next-generation radioisotope-based power system that is currently being developed as an alternative to the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). Power sources such as these may be needed for proposed missions to solar system planets and bodies that have challenging Planetary Protection (PP) requirements (e.g. Mars, Europa, Enceladus) that may support NASA s search for life, remnants of past life, and the precursors of life. One concern is that the heat from the ASRG could potentially create a region in which liquid water may occur. As advised by the NASA Planetary Protection Officer, when deploying an ASRG to Mars, the current COSPAR/NASA PP policy should be followed for Category IVc mission. Thus, sterilization processing of the ASRG to achieve bioburden reduction would be essential to meet the Planetary Protection requirements. Due to thermal constraints and associated low temperature limits of elements of the ASRG, vapor hydrogen peroxide (VHP) was suggested as a candidate alternative sterilization process to complement dry heat microbial reduction (DHMR) for the assembled ASRG. The following proposed sterilization plan for the ASRG anticipates a mission Category IVc level of cleanliness. This plan provides a scenario in which VHP is used as the final sterilization process. Keywords: Advanced Stirling Radioisotope Generator (ASRG), Planetary Protection (PP), Vapor hydrogen peroxide (VHP) sterilization.

  7. Diode-Assisted Buck-Boost Current Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Cai, Liang; Loh, P.C.

    2007-01-01

    This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...... a double current boost capability when comparing with the recently reported buckboost CSIs. For modulating the presented CSIs, two modulation schemes are proposed for achieving either optimized harmonic performance or minimal commutation count, meanwhile keeping the important current buck-boost operation...

  8. Reactors are indispensable for radioisotope production.

    Science.gov (United States)

    Mushtaq, Ahmad

    2010-12-01

    Radioisotopes can be produced by reactors and accelerators. For certain isotopes there could be an advantage to a certain production method. However, nowadays many reports suggest, that useful isotopes needed in medicine, industry and research could be produced efficiently and dependence on reactors using enriched U-235 may be eliminated. In my view reactors and accelerators will continue to play their role side by side in the supply of suitable and economical sources of isotopes.

  9. Radioisotope production in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Wan Anuar Wan Awang [Medical Technology Div., Malaysian Inst. for Nuclear Technology Research (MINT) (Malaysia)

    1998-10-01

    Production of Mo-99 by neutron activation of Mo-99 in Malaysia began as early as 1984. Regular supply of the Tc-99m extracted from it to the hospitals began in early 1988 after going through formal registration with the Malaysian Ministry of Health. Initially, the weekly demand was about 1.2 Ci of Mo-99 which catered the needs of 3 nuclear medicine centres. Sensitive to the increasing demand of Tc-99m, we have producing our own Tc-99m generator from imported TeO{sub 2} because irradiation TeO{sub 2} with our reactor give low yield of I-131. We have established the production of radioisotope for industrial use. By next year, Sm-153 EDTMP will be produce after we have license from our competent authority. (author)

  10. High Current Ion Sources and Injectors for Heavy Ion Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, Joe W.

    2005-02-15

    Heavy ion beam driven inertial fusion requires short ion beam pulses with high current and high brightness. Depending on the beam current and the number of beams in the driver system, the injector can use a large diameter surface ionization source or merge an array of small beamlets from a plasma source. In this paper, we review the scaling laws that govern the injector design and the various ion source options including the contact ionizer, the aluminosilicate source, the multicusp plasma source, and the MEVVA source.

  11. Wheatstone bridge fed from a bilateral constant current source.

    Science.gov (United States)

    Velayudhan, C; Oommen, D

    1980-03-01

    A simple inexpensive scheme of an electronic amplifier for Wheatstone bridge application is presented. The bridge is excited from a bilateral constant current square wave source. The advantage of constant current drive is presented.

  12. NINE LEVEL CURRENT SOURCE INVERTER WITH SOLAR PV

    OpenAIRE

    Othman M. Hussein Anssari

    2016-01-01

    Multi-level current source using main inverter and auxiliary inductor cell is sufficient to the industrial engines because it generate high power. The present inverter consist of a basic H-bridge current source inverter working as a main inverter generates a multilevel current waveform in joining with two inductor cells connected in parallel as auxiliary circuits. The inductor cells work by generating the intermediate level of the multilevel current waveform with no additional external dc-pow...

  13. Low noise constant current source for bias dependent noise measurements

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, D.; Bose, Suvendu; Bardhan, K. K. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Chakraborty, R. K. [Bidhannagar College, EB - 2, Bidhannagar, Kolkata 700064 (India)

    2011-01-15

    A low noise constant current source used for measuring the 1/f noise in disordered systems in ohmic as well as nonohmic regime is described. The source can supply low noise constant current starting from as low as 1 {mu}A to a few tens of milliampere with a high voltage compliance limit of around 20 V. The constant current source has several stages, which can work in a standalone manner or together to supply the desired value of load current. The noise contributed by the current source is very low in the entire current range. The fabrication of a low noise voltage preamplifier modified for bias dependent noise measurements and based on the existing design available in the MAT04 data sheet is also described.

  14. [Research on Constant-current Characteristics of Howland Current Source Used in Bioelectrical Impedance Detection].

    Science.gov (United States)

    Lin, Xingjian; Zhao, Weijie; Liu, Xiaojuan; Li, Lihua

    2015-04-01

    This study aims to analyze and improve Howland current source circuit and to study the constant current source of alternating current with high output impedance and high stability. A simulation study was carried out on the constant-current characteristics of Howland current source from two aspects of resistance match value and the selection of Op amp parameters, and then the output impedance was analyzed. The simulation experiment showed that when it was with the best matched resistance, the constant-current characteristics of Howland current source was better. Op amp parameters could affect the constant-current characteristics of Howland current source. In Howland current source circuit, the current source after parameter optimization had better output impedance and load capacity. The results showed that there was the best matched resistance in the selection by Howland current source. The Op amp with large broadband, high slew rate and open loop gain, and wide range of power supply voltage is more suitable for the bioelectrical impedance detection circuit.

  15. Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    Science.gov (United States)

    Tarau, Calin; Anderson, William G.; Walker, Kara

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the converter stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, and also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) has been designed to allow multiple stops and restarts of the Stirling convertor in an Advanced Stirling Radioisotope Generator (ASRG). When the Stirling convertor is turned off, the VCHP will activate when the temperatures rises 30 C above the setpoint temperature. A prototype VCHP with sodium as the working fluid was fabricated and tested in both gravity aided and against gravity conditions for a nominal heater head temperature of 790 C. The results show very good agreement with the predictions and validate the model. The gas front was located at the exit of the reservoir when heater head temperature was 790 C while cooling was ON, simulating an operating Advanced Stirling Converter (ASC). When cooling stopped, the temperature increased by 30 C, allowing the gas front to move past the radiator, which transferred the heat to the case. After resuming the cooling flow, the front returned at the initial location turning OFF the VCHP. The against gravity working conditions showed a colder reservoir and faster transients.

  16. Milliwatt Radioisotope Stirling Convertor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Studies of potential space missions have highlighted the need for very small electric power supplies for a variety of applications. The light weight radioisotope...

  17. Medical application of radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Woon; Lim, S. M.; Kim, E. H. [and others

    2000-05-01

    In this project, we studied following subjects: 1. Clinical research for radionuclide therapy 2. Development of in vitro assay method with radioisotope 3. Development of binary therapy; Boron neutron capture therapy and photodynamic therapy 4. Development of diagnostic methods in radionuclide imaging. The results can be applied for the following objectives: (1) Radionuclide therapy will be applied in clinical practice to treat the cancer patients or other diseases in multi-center trial (2) The newly developed monoclonal antibodies and biomolecules can be used in biology, chemistry or other basic life science research (3) The new methods for the analysis of therapeutic effects, such as dosimetry, and quantitative analysis methods of radioactivity, can be applied in basic research, such as radiation oncology and radiation biology (4) The result of the project will be expected to develop the new radioimmunoassay for drug monitoring following the clinical experiments (5) Boron porphyrin has been successfully labeled with iodine. This enables the pharmacodynamic study of the boron compound in human body (6) A method to evaluate the biological effect of neutrons on tumor cells has been developed (7) The establishment of macro- and microscopic dose assessment using alpha-track autoradiography (8) Clinical application of PDT in bladder cancers, oropharyngeal cancer and skin cancer (9) Radionuclide imaging of estrogen receptor in breast cancer, lipid metabolism, gene therapy, cancers, brain function and heart disease.

  18. Current Source Converters in Discontinuous Conduction Modes of Operation

    Science.gov (United States)

    Cuzner, Robert M.

    This work demonstrates that Current Source Rectifier (CSR) pulse-width modulation (PWM) can be successfully modified for discontinuous conduction mode (DCM). DCM is characterized by input current distortion and non-linear input to output voltage ratio. A Dead-Beat Current Injection (DBCI) PWM method is developed that ensures sinusoidal input currents and linear input to output voltage control while in DCM. A method for control analysis is proposed that enables design of the CSR closed loop voltage controller. The proposed method is simulated to show that the desired objectives are achieved at no load and very light load, where the CSR operates in an extreme DCM condition. Experimental results verify performance of the DBCI-PWM method and validate both simulation and analytical tools used to explore the capabilities of the approach. Index Terms---Active buck rectifier, Current source rectifier (CSR), current source PWM rectifier, power conversion, power converter design, power converter analysis, input power quality

  19. Development of radioisotope preparation and application technology

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hyon Soo; Park, K. B.; Bang, H. S. [and others

    2000-04-01

    The purpose of this project is to develop RI production technology utility 'HANARO' and to construct a sound infra-structure for mass production and supply to domestic users. The developed contents and results are as follows: two types of rig for irradiation in reactor core were designed and manufactured. The safety of OR rig during irradiation was identified through various test and it is used for RI production. The prepared IR rig will be used to performance tests for safety. We prepared two welders and welding jigs for production of sealed sources, and equipments for quality control of the welded materials. Production processes and apparatus Cr-51, P-32, I-125 and Sr-89, were developed. Developed results would be used for routine production and supply of radioisotopes. The automatic Tc-99m extraction apparatus was supplied to Libya under IAEA support. For approval on special form radioactive material of the developed Ir-192 source assembly and projector documents were prepared and submitted to MOST. The high dose rate Ir-192 source(diameter 1.1 mm, length 5.2 mm) for RALS and the laser welding system for its fabrication were developed. Production technologies of Ir-192 sources for destructive test and medical therapy were transferred to private company for commercial supply. The chemical immobilization method based on the self-assemble monolayer of {omega}-functionalized thiol and the sensing scheme based on the beta-emitter labeling method were developed for the fabrication radioimmuno-sensors. Results of this study will be applied to mass production of radioisotopes 'HANARO' and are to contribute the advance of domestic medicine and industry related to radioisotopes.

  20. Medical Radioisotope Data Survey: 2002 Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, Edward R.

    2004-06-23

    A limited, but accurate amount of detailed information about the radioactive isotopes used in the U.S. for medical procedures was collected from a local hospital and from a recent report on the U.S. Radiopharmaceutical Markets. These data included the total number of procedures, the specific types of procedures, the specific radioisotopes used in these procedures, and the dosage administered per procedure. The information from these sources was compiled, assessed, pruned, and then merged into a single, comprehensive and consistent set of results presented in this report. (PIET-43471-TM-197)

  1. -Norm Regularization in Volumetric Imaging of Cardiac Current Sources

    Directory of Open Access Journals (Sweden)

    Azar Rahimi

    2013-01-01

    Full Text Available Advances in computer vision have substantially improved our ability to analyze the structure and mechanics of the heart. In comparison, our ability to observe and analyze cardiac electrical activities is much limited. The progress to computationally reconstruct cardiac current sources from noninvasive voltage data sensed on the body surface has been hindered by the ill-posedness and the lack of a unique solution of the reconstruction problem. Common L2- and L1-norm regularizations tend to produce a solution that is either too diffused or too scattered to reflect the complex spatial structure of current source distribution in the heart. In this work, we propose a general regularization with Lp-norm ( constraint to bridge the gap and balance between an overly smeared and overly focal solution in cardiac source reconstruction. In a set of phantom experiments, we demonstrate the superiority of the proposed Lp-norm method over its L1 and L2 counterparts in imaging cardiac current sources with increasing extents. Through computer-simulated and real-data experiments, we further demonstrate the feasibility of the proposed method in imaging the complex structure of excitation wavefront, as well as current sources distributed along the postinfarction scar border. This ability to preserve the spatial structure of source distribution is important for revealing the potential disruption to the normal heart excitation.

  2. Performance evaluation of wideband bio-impedance spectroscopy using constant voltage source and constant current source

    Science.gov (United States)

    Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee

    2012-10-01

    Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in

  3. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  4. Results with radioisotope techniques in veterinary science in Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Pethes, G. (Allatorvostudomanyi Egyetem, Budapest (Hungary))

    1983-09-01

    Radioisotopes have been applied to veterinary science in Hungary since the fifties. A short chronologic review on the development of isotope technology is given emphasizing the possibilities offered by the application of closed and open radiation sources, of instrumental neutron activation analysis and atomic absorption spectroscopy, and in vitro nuclear procedures which include competitive protein-binding analysis and radioimmunoassay. The progesterone test, applicable to diagnose the pregnancy of cattles, is carried out generally by RIA. Radioisotopic methods are applied also to determine the thyroid function of cattles, swines and domestic fowls.

  5. First ECR-Ionized Noble Gas Radioisotopes at ISOLDE

    CERN Document Server

    Wenander, F; Gaubert, G; Jardin, P; Lettry, Jacques

    2004-01-01

    The production of light noble gas radioisotopes with high ionization potentials has been hampered by modest ionization efficiencies for standard plasma ion-sources. However, the decay losses are minimal as the lingering time of light noble gases within plasma ion-sources is negligible when compared to its diffusion out of the target material. Previous singly charged ECRIS have shown a higher efficiency but also a lingering time of the order of 1 s and a total weight that prevents remote handling by the ISOLDE robot. The compact MINIMONO efficiently addressed the lingering time and weight issues. In addition, the MINIMONO maintained the high off-line ionization efficiency for light noble gases. This paper describes a standard ISOLDE target unit equipped with a MINIMONO ion-source and the first tests. The ion-source has been tested off-line and equipped with a CaO target for on-line tests. Valuable information was gained about high current (100-500 muA) transport through the ISOLDE mass separators designed for ...

  6. Shielding of electromagnetic fields of current sources by spherical enclosures

    Science.gov (United States)

    Shastry, S. V. K.; Rao, M. N.; Katti, V. R.

    Expressions for the shielding effectiveness of a conductive spherical enclosure excited by a Hertzian dipole have been derived using the dyadic Green's function technique. This technique has the advantage that the fields inside or outside the enclosure due to arbitrary current distribution may be found by employing the same set of dyadic Green's functions. The shielding effectiveness for plane wave incidence has been determined by considering the limiting case of the current source external to the spherical shell. Computed values of shielding effectiveness deduced in this manner have been compared with those obtained by the numerical evaluation of the expressions derived by earlier authors. The theory presented here may be useful to EMC (electromagnetic compatibility) engineers who must consider electromagnetic coupling from current sources in the vicinity of shielding enclosures.

  7. Science Instrument Sensitivities to Radioisotope Power System Environment

    Science.gov (United States)

    Bairstow, Brian; Lee, Young; Smythe, William; Zakrajsek, June

    2016-01-01

    Radioisotope Power Systems (RPS) have been and will be enabling or significantly enhancing for many missions, including several concepts identified in the 2011 Planetary Science Decadal Survey. Some mission planners and science investigators might have concerns about possible impacts from RPS-induced conditions upon the scientific capabilities of their mission concepts. To alleviate these concerns, this paper looks at existing and potential future RPS designs, and examines their potential radiation, thermal, vibration, electromagnetic interference (EMI), and magnetic fields impacts on representative science instruments and science measurements. Radiation impacts from RPS on science instruments are of potential concern for instruments with optical detectors and instruments with high-voltage electronics. The two main areas of concern are noise effects on the instrument measurements, and long-term effects of instrument damage. While RPS by their nature will contribute to total radiation dose, their addition for most missions should be relatively small. For example, the gamma dose rate from one Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) would be an order of magnitude lower than the environmental dose rate at Mars, and would have a correspondingly lower contribution to instrument noise and to any permanent damage to payload sensors. Increasing the number of General Purpose Heat Source (GPHS) modules used in an RPS would be expected to increase the generated radiation proportionally; however, the effect of more GPHS modules is mitigated from a strictly linear relationship by self-shielding effects. The radiation field of an RPS is anisotropic due to the deviation of the modules from a point-source-geometry. For particularly sensitive instruments the total radiation dose could be mitigated with separation or application of spot shielding. Though a new, higher-power RPS could generate more heat per unit than current designs, thermal impact to the flight

  8. Analysis of simple current sources and sinks for differential current mode technology

    Science.gov (United States)

    Gołofit, Krzysztof

    2008-01-01

    The paper introduces the Differential Current Mode Technology (DCMT) - a technique of providing very high security level for cryptographic devices. As distinct from the most Side Channel Attacks (SCA) preventing methods, the DCMT does not rely on concealing, masking or muffling, but minimizes the sources of the leakage. Digital circuits based on DCMT operate with constant and continuous supply current as well as symmetrical differential current-mode inner connections - all with the aim of keeping electromagnetic emanation and power supply disturbances as low as possible. The paper describes the general assumptions for the DCMT, basic model of the DCM-gate, three-valued DCM-logic, rules of differential current arithmetic and basics of binary computations on the basis of the DCMT. A crucial issue for the DCMT in the fields of security, efficiency, power consumption and implementation cost (size on an IC) is designing of current sources and sinks. Trade-off between supply current and propagation time, along with analyses of static and dynamic currents aberrations with regard to sizes of current sinks/sources are presented.

  9. Raw material and materials for production of chemical current sources

    Energy Technology Data Exchange (ETDEWEB)

    Olszanski, S.; Brudka, Z.; Rychlewski, J.

    1982-01-01

    During work to replace imported raw material by domestic in the production of chemical sources of current, the central laboratory of storage batteries and elements of the Polish People's Republic has developed: technology for thermal treatment of inexpensive channel carbon black guaranteeing possibility of using it in agglomerate mixture of manganese chemical current sources (thermal treatment of carbon black, wetting by a solution of weak carboxylic acid conducted in an atmosphere of flue gases at 1100/sup 0/C), expander for negative active mass of the Pb-storage batteries based on lignin formed as wastes in the production of vanilin; gluing thyotropic composite for gluing covers and tanks of storage batteries.

  10. Current-type flipped-Γ-source inverters

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Li, Ding; Blaabjerg, Frede

    2012-01-01

    Z-source inverters are innovative single-stage topologies proposed for flexible buck-boost energy conversion. To raise their gains and modulation ratios further, a number of variations have been introduced with some using magnetically coupled transformers or inductors. These variants are of inter......Z-source inverters are innovative single-stage topologies proposed for flexible buck-boost energy conversion. To raise their gains and modulation ratios further, a number of variations have been introduced with some using magnetically coupled transformers or inductors. These variants...... are of interest since they use lesser components. Their winding turns might however become too excessive for higher demanded gains. Avoiding this usual trend, a new family of current-type flipped-Γ-source inverters are proposed, whose common gain is raised by lowering, and not increasing, the winding turns...

  11. Modelling a Three-Phase Current Source Inverter

    Directory of Open Access Journals (Sweden)

    Neukirchner László

    2016-12-01

    Full Text Available A current source inverter model has been developed in the given paper that is constructed from six LTI models for the different switching modes. The overall model is in a piecewise affine form that supports the use of model predictive control. The model has been verified against engineering expectations and its open-loop performance shows that it is a promising basis of model predictive control structures.

  12. Preparing for Harvesting Radioisotopes from FRIB

    Energy Technology Data Exchange (ETDEWEB)

    Peaslee, Graham F. [Hope College, Holland, MI (United States); Lapi, Suzanne E. [Washington Univ., St. Louis, MO (United States)

    2015-02-02

    The Facility for Rare Isotope Beams (FRIB) is the next generation accelerator facility under construction at Michigan State University. FRIB will produce a wide variety of rare isotopes by a process called projectile fragmentation for a broad range of new experiments when it comes online in 2020. The accelerated rare isotope beams produced in this facility will be more intense than any current facility in the world - in many cases by more than 1000-fold. These beams will be available to the primary users of FRIB in order to do exciting new fundamental research with accelerated heavy ions. In the standard mode of operation, this will mean one radioisotope will be selected at a time for the user. However, the projectile fragmentation process also yields hundreds of other radioisotopes at these bombarding energies, and many of these rare isotopes are long-lived and could have practical applications in medicine, national security or the environment. This project developed new methods to collect these long-lived rare isotopes that are by-products of the standard FRIB operation. These isotopes are important to many areas of research, thus this project will have a broad impact in several scientific areas including medicine, environment and homeland security.

  13. Methodological issues and preliminary results from a combined sediment fingerprinting and radioisotope dating approach to explore changes in sediment sources with land-use change in the Brantian Catchment, Borneo.

    Science.gov (United States)

    Walsh, Rory; Higton, Sam; Marshall, Jake; Bidin, Kawi; Blake, William; Nainar, Anand

    2015-04-01

    This paper reports some methodological issues and early results of a project investigating the erosional impacts of land use changes (multiple selective logging and progressive, partial conversion to oil palm) over the last 25-40 years in the 600km2 Brantian river catchment in Sabah, Borneo. A combined sediment fingerprinting and radioisotope dating approach is being applied to sediment cores taken in stream hierarchical fashion across the intermediate catchment scale. Changes in sediment sources and sedimentation rates over time can be captured by changes in the relative importance of geochemical elements with depth in downstream sediment cores, which in turn can be linked to parallel changes in upstream cores by the application of unmixing models and statistical techniques. Radioisotope analysis of the sediment cores allows these changes to be dated and sedimentation rates to be estimated. Work in the neighbouring Segama catchment had successfully demonstrated the potential of such an approach in a rainforest environment (Walsh et al. 2011). The paper first describes steps taken to address methodological issues. The approach relies on taking continuous sediment cores which have aggraded progressively over time and remain relatively undisturbed and uncontaminated. This issue has been tackled (1) through careful core sampling site selection with a focus on lateral bench sites and (2) deployment of techniques such as repeat-measurement erosion bridge transects to assess the contemporary nature of sedimentation to validate (or reject) candidate sites. The issue of sediment storage and uncertainties over lag times has been minimised by focussing on sets of above- and below-confluence sites in the intermediate zone of the catchment, thus minimising sediment transit times between upstream contributing and downstream destination core sites. This focus on the intermediate zone was also driven by difficulties in finding suitable core sites in the mountainous headwaters

  14. Helium release from radioisotope heat sources

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, D.E.; Early, J.W.; Starzynski, J.S.; Land, C.C.

    1984-05-01

    Diffusion of helium in /sup 238/PuO/sub 2/ fuel was characterized as a function of the heating rate and the fuel microstructure. The samples were thermally ramped in an induction furnace and the helium release rates measured with an automated mass spectrometer. The diffusion constants and activation energies were obtained from the data using a simple diffusion model. The release rates of helium were correlated with the fuel microstructure by metallographic examination of fuel samples. The release mechanism consists of four regimes, which are dependent upon the temperature. Initially, the release is controlled by movement of point defects combined with trapping along grain boundaries. This regime is followed by a process dominated by formation and growth of helium bubbles along grain boundaries. The third regime involves volume diffusion controlled by movement of oxygen vacancies. Finally, the release at the highest temperatures follows the diffusion rate of intragranular bubbles. The tendency for helium to be trapped within the grain boundaries diminishes with small grain sizes, slow thermal pulses, and older fuel.

  15. Applications of radioisotopes in industry and healthcare in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Dien, N.N.; Quang, N.H. [Nucealr Research Institute, Dalat, (Viet Nam)

    1997-10-01

    Nowadays, in Vietnam radioisotopes have been used very widely in various socio-economic branches, especially in industry and healthcare. Applications of radioisotopes have significant meaning in economic development, people health protection, as well as in scientific research. In this paper, the present status and main applications of radiation and radioactive isotopes in industry and healthcare in Vietnam are reported. In order to control and monitor industrial processes, nucleonic control systems and radioactive tracer techniques have been utilized. Actually, sealed source applications are popular in Vietnam industry. A number of nuclear control devices and gauges have been used in the various industrial factories, such as liquid level gauges in steel industry, cement and beverage factories; density and moisture gauges in paper industry, etc. Tracer technique and sealed source applications have also been utilized in industrial production plants and in trouble-shooting in the petroleum industry. For medicine purposes, two departments of nuclear medicine were primarily established at the beginning of the 1970s. At the present time, a number of nuclear medicine departments have been set up and they have been equipped with advanced equipment. Main activities are focused on thyroid function studies, nuclear cardiology, brain scans, gastrointestinal studies, bone scans, etc. Since march 1984 Dalat nuclear research reactor of nominal power of 500 kW has been reconstructed and put into operation. This reactor is unique in Vietnam and has become an important scientific tool for development of nuclear techniques and radioisotope applications for socio-economic progress. Thanks to this important scientific tool, a variety of radioisotopes for medicine and industry applications as well as for scientific research has been produced. Utilization of the Dalat research reactor for radioisotope production is also summarized in this paper

  16. Electric machine and current source inverter drive system

    Science.gov (United States)

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  17. Single-phase Multilevel Current Source Inverter with Reduced Device Count and Current Balancing Capability

    Directory of Open Access Journals (Sweden)

    MOALLEMI KHIAVI, A.

    2015-08-01

    Full Text Available Nowadays power converters play an important role in power system and industrial centers. One of the most important and widely used types of conversion is DC to AC conversion that is also called inverters. Generally inverters are divided to voltage source inverter (VSI and current source inverter (CSI. From another view the inverters are divided to two-level and multilevel types. The multilevel inverters are attractive because of their good output waveform quality. However, there has been less attention to multilevel current source inverter (MLCSI when compared with multilevel VSI. In this paper, a new topology for MLCSI is proposed. The proposed topology employs reduced number of switches to generate desired multilevel output current. The proposed MLCSI is capable of balancing the currents of the inductors that are used in the MLCSI structure. A multicarrier PWM based switching strategy is also proposed for the MLCSI. The simulation results using PSCAD/EMTDC as well as the experimental results from a single-phase 5-level CSI laboratory prototype demonstrate its validity.

  18. Tri-State Current Source Inverter With Improved Dynamic Performance

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Wong, Chow Pang

    2008-01-01

    Traditional dc-ac current source inverter (CSI) has a right-half-plane (RHP) zero in its control-to-output transfer function. This RHP zero causes the inverter output to fall before rising when a step increase in command reference is required (commonly known as non-minimum-phase effect). To achieve...... sequence, the inductive boosting and discharging intervals can be decoupled, allowing the RHP zero to be eliminated with only minor circuit modifications (high level control schemes like predictive and multiloop voltage/current control remain unchanged). The designed inverter can be controlled using...... a better dynamic response, this paper proposes the design of a tri-state CSI using only an additional semiconductor switch for introducing unique freewheeling states to the traditional six active and three null states of a CSI. With the freewheeling states inserted appropriately within the inverter state...

  19. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1985

    Energy Technology Data Exchange (ETDEWEB)

    Baker, D.A.

    1986-08-01

    This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfer - FY 1985.

  20. High current DC negative ion source for cyclotron.

    Science.gov (United States)

    Etoh, H; Onai, M; Aoki, Y; Mitsubori, H; Arakawa, Y; Sakuraba, J; Kato, T; Mitsumoto, T; Hiasa, T; Yajima, S; Shibata, T; Hatayama, A; Okumura, Y

    2016-02-01

    A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H(-) beam of 10 mA and D(-) beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H(-) beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H(-) current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H(-) production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H(-) current dependence on the arc power.

  1. Analysis, Optimization, and Assessment of Radioisotope Thermophotovoltaic System Design for an Illustrative Space Mission

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred; Mukunda, Meera; Summers, G.

    1994-06-28

    A companion paper presented at this conference described the design of a Radioisotope Thermophotovoltaic (RTPV) Generator for an illustrative space mission (Pluto Fast Flyby). It presented a detailed design of an integrated system consisting of a radioisotope heat source, a thermophotovoltaic converter, and an optimized heat rejection system. The present paper describes the thermal, electrical, and structural analyses which led to that optimized design, and compares the computed RTPV performance to that of a Radioisotope Thermoelectric Generator (RTG) designed for the same mission. RTPV's are of course much less mature than RTGs, but our results indicate that - when fully developed - they could result in a 60% reduction of the heat source's mass, cost, and fuel loading, a 50% reduction of generator mass, a tripling of the power system's specific power, and a quadrupling of its efficiency. The paper concludes by briefly summarizing the RTPV's current technology status and assessing its potential applicability for the PFF mission. For other power systems (e.g. RTGs), demonstrating their flight readiness for a long mission is a very time-consuming process to determine the long-term effect of temperature-induced degradation mechanisms. But for the case of the described RTPV design, the paper lists a number of factors, primarily its cold (0 to 10 degrees C) converter temperature, that may greatly reduce the need for long-term tests to demonstrate generator lifetime. In any event, our analytical results suggest that the RTPV generator, when developed by DOE and/or NASA, would be quite valuable not only for the Pluto mission but also for other future missions requiring small, long-lived, low mass generators. Another copy is in the Energy Systems files.

  2. Production capabilities in US nuclear reactors for medical radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadeh, S.; Callahan, A.P.; Knapp, F.F. Jr. (Oak Ridge National Lab., TN (United States)); Schenter, R.E. (Westinghouse Hanford Co., Richland, WA (United States))

    1992-11-01

    The availability of reactor-produced radioisotopes in the United States for use in medical research and nuclear medicine has traditionally depended on facilities which are an integral part of the US national laboratories and a few reactors at universities. One exception is the reactor in Sterling Forest, New York, originally operated as part of the Cintichem (Union Carbide) system, which is currently in the process of permanent shutdown. Since there are no industry-run reactors in the US, the national laboratories and universities thus play a critical role in providing reactor-produced radioisotopes for medical research and clinical use. The goal of this survey is to provide a comprehensive summary of these production capabilities. With the temporary shutdown of the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) in November 1986, the radioisotopes required for DOE-supported radionuclide generators were made available at the Brookhaven National Laboratory (BNL) High Flux Beam Reactor (HFBR). In March 1988, however, the HFBR was temporarily shut down which forced investigators to look at other reactors for production of the radioisotopes. During this period the Missouri University Research Reactor (MURR) played an important role in providing these services. The HFIR resumed routine operation in July 1990 at 85 MW power, and the HFBR resumed operation in June 1991, at 30 MW power. At the time of the HFBR shutdown, there was no available comprehensive overview which could provide information on status of the reactors operating in the US and their capabilities for radioisotope production. The obvious need for a useful overview was thus the impetus for preparing this survey, which would provide an up-to-date summary of those reactors available in the US at both the DOE-funded national laboratories and at US universities where service irradiations are currently or expected to be conducted.

  3. Virtual-Impedance-Based Control for Voltage-Source and Current-Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Li, YunWei; Blaabjerg, Frede

    2015-01-01

    The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator...... for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models...

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

    OpenAIRE

    Mboyi, Kalomba; Ren, Junxue; Liu, Yu

    2015-01-01

    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 e...

  5. PV source based high voltage gain current fed converter

    Science.gov (United States)

    Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

    2017-11-01

    This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

  6. New progress of high current gasdynamic ion source (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga@ipfran.ru; Sidorov, A.; Vodopyanov, A. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Tarvainen, O.; Koivisto, H.; Kalvas, T. [Department of Physics, University of Jyvaskyla, P.O. Box 35 (YFL), 40500 Jyvaskyla (Finland)

    2016-02-15

    The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)—the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller’s ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 10{sup 13} cm{sup −3}) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10{sup −4}–10{sup −3} mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ⋅ mm ⋅ mrad have been demonstrated in recent experiments.

  7. NASA's Radioisotope Power Systems Planning and Potential Future Systems Overview

    Science.gov (United States)

    Zakrajsek, June F.; Woerner, Dave F.; Cairns-Gallimore, Dirk; Johnson, Stephen G.; Qualls, Louis

    2016-01-01

    The goal of NASA's Radioisotope Power Systems (RPS) Program is to make RPS ready and available to support the exploration of the solar system in environments where the use of conventional solar or chemical power generation is impractical or impossible to meet the needs of the missions. To meet this goal, the RPS Program, working closely with the Department of Energy, performs mission and system studies (such as the recently released Nuclear Power Assessment Study), assesses the readiness of promising technologies to infuse in future generators, assesses the sustainment of key RPS capabilities and knowledge, forecasts and tracks the Program's budgetary needs, and disseminates current information about RPS to the community of potential users. This process has been refined and used to determine the current content of the RPS Program's portfolio. This portfolio currently includes an effort to mature advanced thermoelectric technology for possible integration into an enhanced Multi-Mission Radioisotope Generator (eMMRTG), sustainment and production of the currently deployed MMRTG, and technology investments that could lead to a future Stirling Radioisotope Generator (SRG). This paper describes the program planning processes that have been used, the currently available MMRTG, and one of the potential future systems, the eMMRTG.

  8. NASA's Radioisotope Power Systems Planning and Potential Future Systems Overview

    Science.gov (United States)

    Zakrajsek, June F.; Woerner, Dave F.; Cairns-Gallimore, Dirk; Johnson, Stephen G.; Qualis, Louis

    2016-01-01

    The goal of NASA's Radioisotope Power Systems (RPS) Program is to make RPS ready and available to support the exploration of the solar system in environments where the use of conventional solar or chemical power generation is impractical or impossible to meet the needs of the missions. To meet this goal, the RPS Program, working closely with the Department of Energy, performs mission and system studies (such as the recently released Nuclear Power Assessment Study), assesses the readiness of promising technologies to infuse in future generators, assesses the sustainment of key RPS capabilities and knowledge, forecasts and tracks the Programs budgetary needs, and disseminates current information about RPS to the community of potential users. This process has been refined and used to determine the current content of the RPS Programs portfolio. This portfolio currently includes an effort to mature advanced thermoelectric technology for possible integration into an enhanced Multi-Mission Radioisotope Generator (eMMRTG), sustainment and production of the currently deployed MMRTG, and technology investments that could lead to a future Stirling Radioisotope Generator (SRG). This paper describes the program planning processes that have been used, the currently available MMRTG, and one of the potential future systems, the eMMRTG.

  9. Alternative current source based Schottky contact with additional electric field

    Science.gov (United States)

    Mamedov, R. K.; Aslanova, A. R.

    2017-07-01

    Additional electric field (AEF) in the Schottky contacts (SC) that covered the peripheral contact region wide and the complete contact region narrow (as TMBS diode) SC. Under the influence of AEF is a redistribution of free electrons produced at certain temperatures of the semiconductor, and is formed the space charge region (SCR). As a result of the superposition of the electric fields SCR and AEF occurs the resulting electric field (REF). The REF is distributed along a straight line perpendicular to the contact surface, so that its intensity (and potential) has a minimum value on the metal surface and the maximum value at a great distance from the metal surface deep into the SCR. Under the influence of AEF as a sided force the metal becomes negative pole and semiconductor - positive pole, therefore, SC with AEF becomes an alternative current source (ACS). The Ni-nSi SC with different diameters (20-1000 μm) under the influence of the AEF as sided force have become ACS with electromotive force in the order of 0.1-1.0 mV, which are generated the electric current in the range of 10-9-10-7 A, flowing through the external resistance 1000 Ohm.

  10. NASA's Radioisotope Power Systems - Plans

    Science.gov (United States)

    Hamley, John A.; Mccallum, Peter W.; Sandifer, Carl E., II; Sutliff, Thomas J.; Zakrajsek, June F.

    2015-01-01

    NASA's Radioisotope Power Systems (RPS) Program continues to plan and implement content to enable planetary exploration where such systems could be needed, and to prepare more advanced RPS technology for possible infusion into future power systems. The 2014-2015 period saw significant changes, and strong progress. Achievements of near-term objectives have enabled definition of a clear path forward in which payoffs from research investments and other sustaining efforts can be applied. The future implementation path is expected to yield a higher-performing thermoelectric generator design, a more isotope-fuel efficient system concept design, and a robust RPS infrastructure maintained effectively within both NASA and the Department of Energy. This paper describes recent work with an eye towards the future plans that result from these achievements.

  11. Operations of a Radioisotope-based Propulsion System Enabling CubeSat Exploration of the Outer Planets

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Steven Howe; Nathan Jerred; Troy Howe; Adarsh Rajguru

    2014-05-01

    Exploration to the outer planets is an ongoing endeavor but in the current economical environment, cost reduction is the forefront of all concern. The success of small satellites such as CubeSats launched to Near-Earth Orbit has lead to examine their potential use to achieve cheaper science for deep space applications. However, to achieve lower cost missions; hardware, launch and operations costs must be minimized. Additionally, as we push towards smaller exploration beds with relative limited power sources, allowing for adequate communication back to Earth is imperative. Researchers at the Center for Space Nuclear Research are developing the potential of utilizing an advanced, radioisotope-based system. This system will be capable of providing both the propulsion power needed to reach the destination and the additional requirements needed to maintain communication while at location. Presented here are a basic trajectory analysis, communication link budget and concept of operations of a dual-mode (thermal and electric) radioisotope-based propulsion system, for a proposed mission to Enceladus (Saturnian icy moon) using a 6U CubeSat payload. The radioisotope system being proposed will be the integration of three sub-systems working together to achieve the overall mission. At the core of the system, stored thermal energy from radioisotope decay is transferred to a passing propellant to achieve high thrust – useful for quick orbital maneuvering. An auxiliary closed-loop Brayton cycle can be operated in parallel to the thrusting mode to provide short bursts of high power for high data-rate communications back to Earth. Additionally, a thermal photovoltaic (TPV) energy conversion system will use radiation heat losses from the core. This in turn can provide the electrical energy needed to utilize the efficiency of ion propulsion to achieve quick interplanetary transit times. The intelligent operation to handle all functions of this system under optimized conditions adds

  12. Emitted radiation characteristics of plutonium dioxide radioisotope thermoelectric generators

    Science.gov (United States)

    Gingo, P. J.; Steyn, J. J.

    1971-01-01

    The nuclear and emitted radiation characteristics of the radioisotope elements and impurities in commercial grade plutonium dioxide are presented in detail. The development of the methods of analysis are presented. Radioisotope thermoelectric generators (RTG) of 1575, 3468 and 5679 thermal watts are characterized with respect to neutron and gamma photon source strength as well as spatial and number flux distribution. The results are presented as a function of detector position and light element contamination concentration for fuel age ranging from 'fresh' to 18 years. The data may be used to obtain results for given O-18 and Pu-236 concentrations. The neutron and gamma photon flux and dose calculations compare favorably with reported experimental values for SNAP-27.

  13. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  14. Twenty years of Korea radioisotope association history

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-09-15

    This contents has two parts. The first part describes the present and post of Korea radioisotope association which are about the foundation of the association, organization, main projects and vision of the association. The second part is about the use and the prospect of radiation and radioisotope in Korea, which shows the plan of expansion of use of radiation and radioisotope, the prospect and present condition in fields such as medical, industry and farming, product and distribution, research and development of human resources, system and management of safety of radiation.

  15. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1986

    Energy Technology Data Exchange (ETDEWEB)

    Lamar, D.A.

    1987-10-01

    This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1)isotope suppliers, facility contact, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfers for fiscal year 1986.

  16. Comparison of three current sources for single-electrode capacitance measurement

    Science.gov (United States)

    Chen, D. X.; Deng, X.; Yang, W. Q.

    2010-03-01

    The capacitance of a single electrode is usually measured by injecting a current to the electrode and measuring the resultant voltage on the electrode. In this case, a voltage-controlled current source with a high bandwidth is needed because the impedance is inversely proportional to the excitation frequency. In this design note, three different current sources are discussed: (1) the Howland current source, (2) a modified Howland current source, and (3) a dual op-amp current source. The principle and dynamic performances are presented and compared. Simulation and experimental results show that although the Howland current source has the lowest (i.e., worst) output impedance, its output is the most stable among the three current sources when the frequency changes. Therefore, it is suitable for single-electrode capacitance measurement. Initial tests have proven the feasibility of single-electrode capacitance sensor with the Howland current source.

  17. Investigation of Insulation Materials for Future Radioisotope Power Systems

    Science.gov (United States)

    Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

    2013-01-01

    NASA's Radioisotope Power Systems (RPS) Technology Advancement Project is developing next generation high-temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

  18. Investigation of Insulation Materials for Future Radioisotope Power Systems (RPS)

    Science.gov (United States)

    Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

    2013-01-01

    NASA's Radioisotope Power System (RPS) Technology Advancement Project is developing next generation high temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center (GRC) on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

  19. Potential Applications for Radioisotope Power Systems in Support of Human Exploration Missions

    Science.gov (United States)

    Cataldo, Robert L.; Colozza, Anthony J.; Schmitz, Paul C.

    2013-01-01

    Radioisotope power systems (RPS) for space applications have powered over 27 U.S. space systems, starting with Transit 4A and 4B in 1961, and more recently with the successful landing of the Mars Science Laboratory rover Curiosity in August 2012. RPS enable missions with destinations far from the Sun with faint solar flux, on planetary surfaces with dense or dusty atmospheres, and at places with long eclipse periods where solar array sizes and energy storage mass become impractical. RPS could also provide an enabling capability in support of human exploration activities. It is envisioned that with the higher power needs of most human mission concepts, a high efficiency thermal-to-electric technology would be required such as the Advanced Stirling Radioisotope generator (ASRG). The ASRG should be capable of a four-fold improvement in efficiency over traditional thermoelectric RPS. While it may be impractical to use RPS as a main power source, many other applications could be considered, such as crewed pressurized rovers, in-situ resource production of propellants, back-up habitat power, drilling, any mobile or remote activity from the main base habitat, etc. This paper will identify potential applications and provide concepts that could be a practical extension of the current ASRG design in providing for robust and flexible use of RPS on human exploration missions.

  20. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1984

    Energy Technology Data Exchange (ETDEWEB)

    Baker, D.A.

    1985-08-01

    This edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research (ER-73), Office of Energy Research, Department of Energy (DOE). This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfers - FY 1984.

  1. Radioisotope Power Systems Technology Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radioisotope Power Systems (RPS) is a multicenter, multiagency (with the Department of Energy (DOE)) program whose purpose is to manage the Science Mission...

  2. Medical Radioisotopes Production Without A Nuclear Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Van der Keur, H.

    2010-05-15

    This report is answering the key question: Is it possible to ban the use of research reactors for the production of medical radioisotopes? Chapter 2 offers a summarized overview on the history of nuclear medicine. Chapter 3 gives an overview of the basic principles and understandings of nuclear medicine. The production of radioisotopes and its use in radiopharmaceuticals as a tracer for imaging particular parts of the inside of the human body (diagnosis) or as an agent in radiotherapy. Chapter 4 lists the use of popular medical radioisotopes used in nuclear imaging techniques and radiotherapy. Chapter 5 analyses reactor-based radioisotopes that can be produced by particle accelerators on commercial scale, other alternatives and the advantages of the cyclotron. Chapter 6 gives an overview of recent developments and prospects in worldwide radioisotopes production. Chapter 7 presents discussion, conclusions and recommendations, and is answering the abovementioned key question of this report: Is it possible to ban the use of a nuclear reactor for the production of radiopharmaceuticals? Is a safe and secure production of radioisotopes possible?.

  3. Development of radioisotope tracer technology

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee; Park, Soon Chul; Lim, Dong Soon; Kim, Jae Ho; Lee, Jae Choon; Lee, Doo Sung; Cho, Yong Suk; Shin, Sung Kuan

    2000-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and to build a strong tracer group to support the local industries. In relation to the tracer technology in 1999, experiments to estimate the efficiencies of a sludge digester of a waste water treatment plant and a submerged biological reactor of a dye industry were conducted. As a result, the tracer technology for optimization of facilities related to wastewater treatment has been developed and is believed to contribute to improve their operation efficiency. The quantification of the experimental result was attempted to improve the confidence of tracer technology by ECRIN program which basically uses the MCNP simulation principle. Using thin layer activation technique, wear of tappet shim was estimated. Thin layer surface of a tappet shim was irradiated by proton beam and the correlation between the measured activity loss and the amount of wear was established. The equipment was developed to adjust the energy of proton which collides with the surface of tappet. The tracer project team has participated into the tracer test for estimating the efficiency of RFCC system in SK cooperation. From the experiment the tracer team has obtained the primary elements to be considered for judging the efficiency of RFCC unit. By developing the tracer techniques to test huge industrial units like RFCC, the tracer team will be able to support the local industries that require technical services to solve any urgent trouble. (author)

  4. Early radioisotope uses in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, N.; Tejera, A.; Bulbulian, S.; Palma, F

    1991-10-15

    Mexico is traditionally a mining country and the first information about the presence of uranium is related to mine exploitation. Around 1945 when uranium became economically important, a rumor had spread that large amounts of black ceramics from Oaxaca were being purchased and sent abroad because of its assumed high uranium content. It was only in 1949 when minerals containing thorium and uranium were declared by law as 'National Reserves'. In those years a radium emanation plant was installed at the 'Hospital General' in Mexico City with the main purpose of carrying out radon seed implantation in tumors. In the fifties a radium dial painting facility was operating in the city of Toluca some 70 km from Mexico City. In 1955, when the National Commission of Nuclear Energy (CNEN) was founded by a government decree, two main activities were in sight: a training program on 'Radioisotope Techniques and Nuclear Instrumentation' and the creation of specialized laboratories. In this paper a general description of these events and undertakings spanning the decades 1940 to 1970 is given. (Author)

  5. KAERI's challenge to steady production of radioisotopes and radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Han, H.S.; Park, K.B. [Korea Atomic Energy Research Institute, Taejon (Korea)

    2000-10-01

    The Korea Atomic Energy Research Institute (KAERI) is a national organization in Korea, and has been doing many research and development works in radioisotope production and applications for more than 30 years. Now KAERI regularly produces radioisotopes (I-131, Tc-99m, Ho-166) for medical use and Ir-192 for industrial use. Various I-131 labeled compounds and more than 10 kinds of Tc-99m cold kits are also produced. Our multi-purpose reactor, named HANARO, has been operative since April of 1995. HANAKO is an open tank type reactor with 30 MW thermal capacity. This reactor was designed not only for research on neutron utilization but for production of radioisotopes. KAERI intended to maximize the radioisotope production capability. For this purpose, radioisotope production facilities (RIPF) have been constructed adjacent to the HANARO reactor building. There are four banks of hot cells equipped with manipulators and some of the hot cells were installed according to the KGMP standards and with clean rooms. In reviewing our RI production plan intensively, emphasis was placed on the development of new radiopharmaceuticals, development of new radiation sources for industrial and therapeutic use, and steady production of selected radioisotopes and radiopharmaceuticals. The selected items are Ho-166 based pharmaceuticals, fission Mo-99/Tc-99m generators. solution and capsules of I-131, and Ir-192 and Co-60 for industrial use. The status and future plan of KAERI's research and development program will be introduced, and will highlight programs for steady production. (author)

  6. Currents trends in the application of IBA techniques to air pollution source fingerprinting and source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, David; Stelcer, Ed.; Atanacio, Armand; Crawford, Jagoda [Australian Nuclear Science and Technology Organisation, Kirrawee DC (Australia)

    2013-07-01

    Full text: IBA techniques have been used for many years to characterise fine particle air pollution. This is not new the techniques are well established. Typically 2-3 MeV protons are used to bombard thin filter papers and up to four simultaneous techniques like PIXE, PIGE, RBS and ERDA will be applied to obtain (μg/g) concentrations for elements from hydrogen to lead. Generally low volume samplers are used to sample between 20-30 m{sup 3} of air over a 24 hour period, this together with IBA's sensitivity means that concentrations down to 1 ng/m{sup 3} of air sampled can be readily achieved with only a few minutes of proton irradiation. With these short irradiation times and low sensitivities for a broad range of elements in the periodic table, large numbers of samples can be obtained and analysed very quickly and easily. At ANSTO we have used IBA methods to acquire a database of over 50,000 filters from 85 different sites through Australia and Asia, each filter has been analysed for more than 21 different chemical species. Large databases extending over many years means that modern statistical techniques like positive matrix factorisation (PMF) can be used to define well characterised source fingerprints and source contributions for a range of different fine particle air pollutants. In this paper we will discuss these PMF techniques and show how they identify both natural sources like sea spray and windblown soils as well as anthropogenic sources like automobiles, biomass burning, coal-fired power stations and industrial emissions. These data are particularly useful for Governments, EPA's and managers of pollution to better understanding pollution sources and their relative contributions and hence to better manage air pollution. Current trends are to take these IBA and PMF techniques a step further and to combine them with wind speed and back trajectory data to better pin point and identify emission sources. We show how this is now being applied on both

  7. Current-voltage model of LED light sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2012-01-01

    Amplitude modulation is rarely used for dimming light-emitting diodes in polychromatic luminaires due to big color shifts caused by varying magnitude of LED driving current and nonlinear relationship between intensity of a diode and driving current. Current-voltage empirical model of light...

  8. Progress on 241Am Production for Use in Radioisotope Power Systems

    Science.gov (United States)

    Baker, S. R.; Bell, K. J.; Brown, J.; Carrigan, C.; Carrott, M. J.; Gregson, C.; Clough, M.; Maher, C. J.; Mason, C.; Rhodes, C. J.; Rice, T. G.; Sarsfield, M. J.; Stephenson, K.; Taylor, R. J.; Tinsley, T. P.; Woodhead, D. A.; Wiss, T.

    2014-08-01

    Electrical power sources used in outer planet missions are a key enabling technology for data acquisition and communications. Power sources generate electricity from the thermal energy from alpha decay of the radioisotope 238Pu via thermo-electric conversion. Production of 238Pu requires specialist facilities including a nuclear reactor and reprocessing plants that are expensive to build and operate, so naturally, a more economical alternative is attractive to the industry. Within Europe 241Am is a feasible alternative to 238Pu that can provide a heat source for radioisotope thermoelectric generators (RTGs) and radioisotope heating units (RHUs). As a daughter product of 241Pu decay, 241Am is present at 1000s kg levels within the UK civil plutonium stockpile.A chemical separation process is required to extract the 241Am in a pure form and this paper describes such a process, successfully developed to the proof of concept stage.

  9. Current schemes for National Synchrotron Light Source UV beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.P.; Howells, M.R.; McKinney, W.R.

    1979-01-01

    We describe in some detail four beamlines proposed for the National Synchrotron Light Source uv ring at Brookhaven National Laboratory. Three grazing-incidence instruments, one of the plane grating Mijake type and two with toroidal gratings at grazing angles of 2-1/2/sup 0/ and 15/sup 0/ are described. Two normal incidence instruments, one using the source as entrance slit and accepting 75 milliradians horizontally are also discussed. In each case we have estimated the output fluxes expected from such beamlines.

  10. G-189A analytical simulation of the integrated waste management-water system using radioisotopes for thermal energy

    Science.gov (United States)

    Coggi, J. V.; Loscutoff, A. V.; Barker, R. S.

    1973-01-01

    An analytical simulation of the RITE-Integrated Waste Management and Water Recovery System using radioisotopes for thermal energy was prepared for the NASA-Manned Space Flight Center (MSFC). The RITE system is the most advanced concept water-waste management system currently under development and has undergone extended duration testing. It has the capability of disposing of nearly all spacecraft wastes including feces and trash and of recovering water from usual waste water sources: urine, condensate, wash water, etc. All of the process heat normally used in the system is produced from low penalty radioisotope heat sources. The analytical simulation was developed with the G189A computer program. The objective of the simulation was to obtain an analytical simulation which can be used to (1) evaluate the current RITE system steady state and transient performance during normal operating conditions, and also during off normal operating conditions including failure modes; and (2) evaluate the effects of variations in component design parameters and vehicle interface parameters on system performance.

  11. Parametric System Model for a Stirling Radioisotope Generator

    Science.gov (United States)

    Schmitz, Paul C.

    2015-01-01

    A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of the Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 Wth) modules as the thermal building block from which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass, and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component- and system-level trades.

  12. Diffusion of Implanted Radioisotopes in Solids

    CERN Multimedia

    2002-01-01

    Implantation of radioisotopes into metal and semiconductor samples is performed. The implanted isotope or its decay-product should have a half-life long enough for radiotracer diffusion experiments. Such radioisotopes are utilized to investigate basic diffusion properties in semiconductors and metals and to improve our understanding of the atomic mechanisms of diffusion. For suitably chosen systems the combination of on-line production and clean implantation of radioisotopes at the ISOLDE facility opens new possibilities for diffusion studies in solids. \\\\ \\\\ The investigations are concentrated on diffusion studies of $^{195}$Au in amorphous materials. The isotope $^{195}$Au was obtained from the mass 195 of the mercury beam. $^{195}$Hg decays into $^{195}$Au which is a very convenient isotope for diffusion experiments. \\\\ \\\\ It was found that $^{195}$Au is a slow diffusor in amorphous Co-Zr alloys, whereas Co is a fast diffusor in the same matrix. The ``asymmetry'' in the diffusion behaviour is of considerab...

  13. Commercial Superconducting Electron Linac for Radioisotope Production

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, Terry Lee [Niowave, Inc., Lansing, MI (United States); Boulware, Charles H. [Niowave, Inc., Lansing, MI (United States); Hollister, Jerry L. [Niowave, Inc., Lansing, MI (United States); Jecks, Randall W. [Niowave, Inc., Lansing, MI (United States); Mamtimin, Mayir [Niowave, Inc., Lansing, MI (United States); Starovoitova, Valeriia [Niowave, Inc., Lansing, MI (United States)

    2015-08-13

    The majority of radioisotopes used in the United States today come from foreign suppliers or are generated parasitically in large government accelerators and nuclear reactors. Both of these restrictions limit the availability of radioisotopes and discourage the development and evaluation of new isotopes and for nuclear medicine, science, and industry. Numerous studies have been recommending development of dedicated accelerators for production of radioisotopes for over 20 years (Institute of Medicine, 1995; Reba, et al, 2000; National Research Council, 2007; NSAC 2009). The 2015 NSAC Long Range Plan for Isotopes again identified electron accelerators as an area for continued research and development. Recommendation 1(c) from the 2015 NSAC Isotope report specifically identifies electron accelerators for continued funding for the purpose of producing medical and industrial radioisotopes. Recognizing the pressing need for new production methods of radioisotopes, the United States Congress passed the American Medical Isotope Production Act of 2012 to develop a domestic production of 99Mo and to eliminate the use of highly enriched uranium (HEU) in the production of 99Mo. One of the advantages of high power electron linear accelerators (linacs) is they can create both proton- and neutron-rich isotopes by generating high energy x-rays that knock out protons or neutrons from stable atoms or by fission of uranium. This allows for production of isotopes not possible in nuclear reactors. Recent advances in superconducting electron linacs have decreased the size and complexity of these systems such that they are economically competitive with nuclear reactors and large, high energy accelerators. Niowave, Inc. has been developing a radioisotope production facility based on a superconducting electron linac with liquid metal converters.

  14. Low Temperature Heat Source Utilization Current and Advanced Technology

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, James H. Jr.; Dambly, Benjamin W.

    1992-06-01

    Once a geothermal heat source has been identified as having the potential for development, and its thermal, physical, and chemical characteristics have been determined, a method of utilization must be decided upon. This compendium will touch upon some of these concerns, and hopefully will provide the reader with a better understanding of technologies being developed that will be applicable to geothermal development in East Africa, as well as other parts of the world. The appendices contain detailed reports on Down-the-Well Turbo Pump, The Vapor-Turbine Cycle for Geothermal Power Generation, Heat Exchanger Design for Geothermal Power Plants, and a Feasibility Study of Combined Power and Water Desalting Plant Using Hot Geothermal Water. [DJE-2005

  15. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1982

    Energy Technology Data Exchange (ETDEWEB)

    Richards, M.P.

    1983-08-01

    The radioisotope production and distribution activities by facilities at Argonne National Laboratory, Pacific Northwest Laboratory, Brookhaven National Laboratory, Hanford Engineering Development Laboratory, Idaho Operations Office, Los Alamos Scientific Laboratory, Oak Ridge National Laboratory, Savannah River Laboratory, and UNC Nuclear Industries, Inc. are listed. The information is divided into five sections: isotope suppliers, facility, contacts, and isotopes or services supplied; alphabetical list of customers, and isotopes purchased; alphabetical list of isotopes cross-referenced to customs numbers; geographical location of radioisotope customers; and radioisotope sales and transfers-FY 1982. (MHR)

  16. High-current Standing Wave Linac With Gyrocon Power Source

    CERN Document Server

    Karliner, M M; Makarov, I G; Nezhevenko, O A; Ostreiko, G N; Persov, B Z; Serdobintsev, G V

    2004-01-01

    A gyrocon together with high-voltage 1.5 MeV accelerator ELIT-3A represents a power generator at 430 MHz serving for linear electron accelerator pulse driving. The facility description and results of calorimetric measurements of ELIT-3A electron beam power and accelerated beam at the end of accelerator are presented in the paper. 2.2 amps of pulsed current have been obtained at electron energy of 20 MeV. The achieved energy conversion efficiency is about 55%.

  17. Mitigation of Grid Current Distortion for LCL-Filtered Voltage Source Inverter with Inverter Current Feedback Control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2018-01-01

    LCL filters feature low inductance; thus, the injected grid current from an LCL-filtered Voltage Source Inverter (VSI) can be easily distorted by grid voltage harmonics. This problem is especially tough for the control system with Inverter-side Current Feedback (ICF), since the grid current....... The potential instability introduced by the compensation loop can be avoided through a special design of the compensation position. Finally, the effectiveness of the proposed method for harmonic rejection is verified by detailed experimental results....

  18. Plasma sources for high-current electron beam generation

    Science.gov (United States)

    Krasik, Ya. E.; Dunaevsky, A.; Felsteiner, J.

    2001-05-01

    A review of experimental studies of the operation of cathodes made of metal-ceramic, velvet, corduroy, carbon fibers, carbon fabric, and different types of ferroelectrics is presented. These cathodes operated at electric fields in the range of 5-60 kV/cm that allowed the generation of electron beams with duration of several hundreds of nanoseconds while keeping a quasi-constant diode impedance. All cathodes had the same diameter and were tested in a diode powered by a high-voltage generator (300 kV, 85 Ω, 250 ns, ⩽5 Hz). It was shown that the source of electrons for all the studied cathodes is a plasma which is formed as a result of surface discharges. Different types of electrical and optical diagnostics were used to study the formation and parameters of the plasma, the potential distribution inside the anode-cathode gap, and the uniformity and divergence of the extracted electron beam as a function of the amplitude and rise time of the accelerating pulse. Results of the lifetime of the tested cathodes and their compatibility with vacuum requirements are presented as well.

  19. Advanced Stirling Convertor Control Unit Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

    Science.gov (United States)

    Dugala, Gina M.; Taylor, Linda M.; Kussmaul, Michael; Casciani, Michael; Brown, Gregory; Wiser, Joel

    2017-01-01

    Future NASA missions could include establishing Lunar or Martian base camps, exploring Jupiters moons and travelling beyond where generating power from sunlight may be limited. Radioisotope Power Systems (RPS) provide a dependable power source for missions where inadequate sunlight or operational requirements make other power systems impractical. Over the past decade, NASA Glenn Research Center (GRC) has been supporting the development of RPSs. The Advanced Stirling Radioisotope Generator (ASRG) utilized a pair of Advanced Stirling Convertors (ASC). While flight development of the ASRG has been cancelled, much of the technology and hardware continued development and testing to guide future activities. Specifically, a controller for the convertor(s) is an integral part of a Stirling-based RPS. For the ASRG design, the controller maintains stable operation of the convertors, regulates the alternating current produced by the linear alternator of the convertor, provides a specified direct current output voltage for the spacecraft, synchronizes the piston motion of the two convertors in order to minimize vibration as well as manage and maintain operation with a stable piston amplitude and hot end temperature. It not only provides power to the spacecraft but also must regulate convertor operation to avoid damage to internal components and maintain safe thermal conditions after fueling. Lockheed Martin Coherent Technologies has designed, developed and tested an Engineering Development Unit (EDU) Advanced Stirling Convertor Control Unit (ACU) to support this effort. GRC used the ACU EDU as part of its non-nuclear representation of a RPS which also consists of a pair of Dual Advanced Stirling Convertor Simulator (DASCS), and associated support equipment to perform a test in the Radioisotope Power Systems System Integration Laboratory (RSIL). The RSIL was designed and built to evaluate hardware utilizing RPS technology. The RSIL provides insight into the electrical

  20. 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.

  1. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1980

    Energy Technology Data Exchange (ETDEWEB)

    Burlison, J.S. (comp.)

    1981-08-01

    The sixteenth edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research, Office of energy Research, Department of Energy (DOE). This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Brookhaven National Laboraory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Facility; Oak Ridge National Laboratory; Savannah River Laboratory; and UNC Nuclear Industries, Inc. The information is divided into five sections: (1) isotope suppliers, facility, contracts and isotopes or services supplied; (2) alphabetical list of customers, and isotopes purchased; (3) alphabetical list of isotopes cross-referenced to customer numbers; (4) geographical location of radioisotope customers; and (5) radioisotope sales and transfers-FY 1980.

  2. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1981

    Energy Technology Data Exchange (ETDEWEB)

    Burlison, J.S. (comp.)

    1982-09-01

    The seventeenth edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research, Office of Energy Research, Department of Energy (DOE). This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory: Pacific Northwest Laboratory; Brookhaven National Laboratory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Facility; Oak Ridge National Laboratory; Savannah River Laboratory; and UNC Nuclear Industries, Inc. The information is divided into five sections: (1) isotope suppliers, facility, contracts and isotopes or services supplied; (2) alphabetical list of customers, and isotopes purchased; (3) alphabetical list of isotopes cross-referenced to customer numbers; (4) geographical location of radioisotope customers; and (5) radioisotope sales and transfers-FY 1980.

  3. Development of radioisotope production in the Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Cabalfin, E.G. [Philippine Nuclear Research Institute, Quezon (Philippines)

    1998-10-01

    The Philippine Nuclear Research Institute (PNRI) started its activities on radioisotope production more than three decades ago, when the Philippine Research Reactor (PRR-1) started operating at its full rated power of 1 MW. Since then, several radionuclides in different chemical forms, were routinely produced and supplied for use in nuclear medicine, industry, agriculture, research and training, until the conversion of the PRR-1 to a 3 MW TRIGA type reactor. After the criticality test of the upgraded reactor, a leak was discovered in the pool liner. With the repair of the reactor still ongoing, routine radioisotope production activities have been reduced to dispensing of imported bulk {sup 131}I. In the Philippines, radioisotopes are widely used in nuclear medicine, with {sup 131}I and {sup 99m}Tc as the major radionuclides of interest. Thus the present radioisotope production program of PNRI is directed to meet this demand. With the technical assistance of the International Atomic Energy Agency (IAEA), PNRI is setting up a new {sup 131}I production facility. The in-cell equipment have been installed and tested using both inactive and active target, obtained from BATAN, Indonesia. In order to meet the need of producing {sup 99}Mo-{sup 99m}Tc generators, based on low specific activity reactor-produced {sup 99}Mo, research and development work on the preparation of {sup 99m}Tc gel generators is ongoing. (author)

  4. Radioisotopes as Political Instruments, 1946–1953

    Science.gov (United States)

    Creager, Angela N. H.

    2009-01-01

    The development of nuclear “piles,” soon called reactors, in the Manhattan Project provided a new technology for manufacturing radioactive isotopes. Radioisotopes, unstable variants of chemical elements that give off detectable radiation upon decay, were available in small amounts for use in research and therapy before World War II. In 1946, the U.S. government began utilizing one of its first reactors, dubbed X-10 at Oak Ridge, as a production facility for radioisotopes available for purchase to civilian institutions. This program of the U.S. Atomic Energy Commission was meant to exemplify the peacetime dividends of atomic energy. The numerous requests from scientists outside the United States, however, sparked a political debate about whether the Commission should or even could export radioisotopes. This controversy manifested the tension in U.S. politics between scientific internationalism as a tool of diplomacy, associated with the aims of the Marshall Plan, and the desire to safeguard the country’s atomic monopoly at all costs, linked to American anti-Communism. This essay examines the various ways in which radioisotopes were used as political instruments—both by the U.S. federal government in world affairs, and by critics of the civilian control of atomic energy—in the early Cold War. PMID:20725612

  5. Low power current sources for bioimpedance measurements: A comparison between Howland and integrated CMOS OTA circuits

    OpenAIRE

    Pedro Bertemes-Filho; Volney Coelho Vincence; Marcio S Santos; Ilson Xavier Zanatta

    2012-01-01

    Electrical Bioimpedance Analysis has been widely used as a non-invasive technique for characterizing tissues. Most systems use a wideband and a high precision instrumentation, specially the current source. The objective of this work is to compare the Howland circuit with three OTA-based floating voltage controlled current sources. The results show that both Current Conveyor and class-AB OTA have a wider output current frequency response and both output impedance is 226 % bigger than the Howla...

  6. Joint Radioisotope Electric Propulsion Studies - Neptune System Explorer

    Science.gov (United States)

    Khan, M. Omair; Amini, Rashied; Ervin, Joan; Lang, Jared; Landau, Damon; Oleson, Steven; Spilker, Thomas; Strange, Nathan

    2011-01-01

    The Neptune System Explorer (NSE) mission concept study assessed opportunities to conduct Cassini-like science at Neptune with a radioisotope electric propulsion (REP) based spacecraft. REP is based on powering an electric propulsion (EP) engine with a radioisotope power source (RPS). The NSE study was commissioned under the Joint Radioisotope Electric Propulsion Studies (JREPS) project, which sought to determine the technical feasibility of flagship class REP applications. Within JREPS, special emphasis was given toward identifying tall technology tent poles, as well as recommending any new RPS technology developments that would be required for complicated REP missions. Based on the goals of JREPS, multiple RPS (e.g. thermoelectric and Stirling based RPS) and EP (e.g. Hall and ion engines) technology combinations were traded during the NSE study to determine the most favorable REP design architecture. Among the findings from the study was the need for >400We RPS systems, which was driven by EP operating powers and the requirement for a long-lived mission in the deep solar system. Additionally multiple development and implementation risks were identified for the NSE concept, as well as REP missions in general. Among the strengths of the NSE mission would be the benefits associated with RPS and EP use, such as long-term power (approx. 2-3kW) at Neptune and flexible trajectory options for achieving orbit or tours of the Neptune system. Although there are still multiple issues to mitigate, the NSE concept demonstrated distinct advantages associated with using REP for deep space flagship-class missions.

  7. Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2016-12-01

    Full Text Available This paper proposes a balanced current control strategy for the current source rectifier (CSR stage of an indirect matrix converter (IMC under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the proposed control strategy under unbalanced grid voltage conditions, the stability and life span of the overall system can be improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

  8. Design of the LC+trap filter for a current source rectifier

    DEFF Research Database (Denmark)

    Min, Huang; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    This paper investigates an LC + trap filter for current source converters to improve the switching harmonic attenuation. The resonant frequency characteristics of the filter of current source rectifier are analyzed. A filter design procedure is proposed based on the input power factor, filter...

  9. Environmental Testing of Tritium-Phosphor Glass Vials for Use in Long-Life Radioisotope Power Conversion Units

    Science.gov (United States)

    Zemcov, Michael; Cardona, Pedro; Parkus, James; Patru, Dorin; Yost, Valerie

    2017-01-01

    Power generation in extreme environments, such as the outer solar system, the night side of planets, or other low-illumination environments, currently presents a technology gap that challenges NASA's ambitious scientific goals. We are developing a radioisotope power cell (RPC) that utilizes commercially available tritium light sources and standard 1.85 eV InGaP2 photovoltaic cells to convert beta particle energy to electric energy. In the test program described here, we perform environmental tests on commercially available borosilicate glass vials internally coated with a ZnS luminescent phosphor that are designed to contain gaseous tritium in our proposed power source. Such testing is necessary to ensure that the glass containing the radioactive tritium is capable of withstanding the extreme environments of launch and space for extended periods of time.

  10. Solar quiet day ionospheric source current in the West African region

    Directory of Open Access Journals (Sweden)

    Theresa N. Obiekezie

    2013-05-01

    Full Text Available The Solar Quiet (Sq day source current were calculated using the magnetic data obtained from a chain of 10 magnetotelluric stations installed in the African sector during the French participation in the International Equatorial Electrojet Year (IEEY experiment in Africa. The components of geomagnetic field recorded at the stations from January–December in 1993 during the experiment were separated into the source and (induced components of Sq using Spherical Harmonics Analysis (SHA method. The range of the source current was calculated and this enabled the viewing of a full year’s change in the source current system of Sq.

  11. A wide-band AC-coupled current source for electrical impedance tomography.

    Science.gov (United States)

    Bragós, R; Rosell, J; Riu, P

    1994-05-01

    A current source suitable for application in electrical impedance tomography (EIT) is described. The first stage of the commercially available current-feedback amplifier AD844 constitutes a current-conveyor implementation and allows the construction of wide-bandwidth current sources, thus avoiding the mismatching and temperature-induced problems that arise in discrete realizations. The lack in gain accuracy of this circuit is overcome by the inclusion of its input buffer in an operational amplifier (op amp) feedback loop. Saturation problems that appear when placing a DC-blocking capacitor between the source and the electrode are solved by a DC feedback that maintains DC voltage at the output near to 0 V without reducing the output impedance of the source. Two AC-coupled current sources, in both inverting and non-inverting configurations, are described and their possible applications to EIT are listed.

  12. A Grid-Connected Multilevel Current Source Inverter and Its Protection for Grid-Disconnection

    OpenAIRE

    Nimrod Vázquez; Luz del Carmen García; Claudia Hernández; Eslí Vázquez; Héctor López; Ilse Cervantes; Juan Iturria

    2013-01-01

    Traditionally DC-AC converters are considered with voltage source inverters (VSI); although less studied and discussed, it has started recently to be used current source inverters (CSI). Another possibility for DC/AC conversion is the multilevel configuration. This paper shows experimental operation and simulation analysis of a grid-connected multilevel current source inverter (MCSI), which includes a circuit for equipment safety reasons due to grid disconnections.

  13. Beam current feedback regulation of the RF neutral beam sources of ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Franzen, P. E-mail: peter.franzen@ipp.mpg.de; Obermayer, S.; Schaeffler, J.; Staebler, A.; Speth, E.; Vollmer, O

    2001-10-01

    This paper reports on the technical implementation and the successful commissioning of the beam current feedback regulation system of the RF neutral beam sources for ASDEX Upgrade. The beam current is regulated by adjusting the RF input power. This is possible due to the fast response of the beam current to changes of the RF input power within a few milliseconds. With beam current feedback regulation, perveanced-matched operation of the sources can be maintained throughout the pulse, thereby increasing the beam quality and the source reliability.

  14. Modified Level Restorers Using Current Sink and Current Source Inverter Structures for BBL-PT Full Adder

    Directory of Open Access Journals (Sweden)

    V. R. Tirumalasetty

    2012-12-01

    Full Text Available Full adder is an essential component for the design and development of all types of processors like digital signal processors (DSP, microprocessors etc. In most of these systems adder lies in the critical path that affects the overall speed of the system. So enhancing the performance of the 1-bit full adder cell is a significant goal. In this paper, we proposed two modified level restorers using current sink and current source inverter structures for branch-based logic and pass-transistor (BBL-PT full adder [1]. In BBL-PT full adder, there lies a drawback i.e. voltage step existence that could be eliminated in the proposed logics by using the current sink inverter and current source inverter structures. The proposed full adders are compared with the two standard and well-known logic styles, i.e. conventional static CMOS logic and Complementary Pass transistor Logic (CPL, demonstrated the good delay performance. The implementation of 8-bit ripple carry adder based on proposed full adders are finally demonstrated. The CPL 8-bit RCA and as well as the proposed ones is having better delay performance than the static CMOS and BBL-PT 8-bit RCA. The performance of the proposed BBL-PT cell with current sink & current source inverter structures are examined using PSPICE and the model parameters of a 0.13 µm CMOS process.

  15. Beam Current Increase and Cathode Lifetime Improvement of KOTRON-13 Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W. K.; Chae, S. K.; Song, J. Y.; Im, G. S.; Cho, B. O. [Samyoung Unitech Co., Seoul (Korea, Republic of)

    2010-05-15

    Technology of cyclotron has been actively developed to meet the increasing requirement output of medical radioactive isotopes for PET. KOTRON-13 is produced with low negative hydrogen ion beam current owing to the low efficiency of proton beam current compared with foreign cyclotron. In the defect there from, the lifetime of cathode is around 5,000min, which requires frequent maintenance period, and the target beam current is maximum 50uA at a poor efficiency compared with the inflow quantity of hydrogen gas and that of inflicting arc current. Considering above affairs, we have to improve the PIG ion source extraction efficiency of KOTRON-13 in order to lift beam current. Mostly the ion source of cyclotron less than 30Mev comes from the use of PIG ion source mainly with the method of cold cathode or hot cathode. However, the cyclotron of 30Mev grade of EBCO or IBA uses the external ion source and uses ion source with cusp type of good withdrawal efficiency. This type requires high voltage, and transports ion from ion source to cyclotron, which requires precise transportation equipment. And entering cyclotron requires a high quality of inflictor with a high defect rate, but high current cyclotron has no choice but to use ion source of such a method. But the cyclotron using PET with the beam current less than 100uA uses PIG ion source of KOTRON-13 with a reasonable maintenance cost

  16. A Modified Droop Control Method for Parallel-Connected Current Source Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    In this paper, a novel control method was proposed for current source inverters under the grid-connected working mode. The control scheme is based on a modified droop control method, with an additional current reference signal that will be generated instead of the voltage reference. Hence......, there is only a current control loop with droop control in the whole control scheme without voltage control loop. So it is very suitable for grid-connected current source inverter which will simplify the design of the control scheme and combine the advantage of droop control. The parallel configuration...... is widely used to acquire high power demand, but the circulating current problem is a key issue that should be considered. In this paper, a simulation based on parallel current source inverters using the proposed control scheme is provided. Simulation results showed that a good circulating current...

  17. Mitigation of Grid Current Distortion for LCL-Filtered Voltage Source Inverter with Inverter Current Feedback Control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2017-01-01

    harmonics can freely flow into the filter capacitor. In this case, because of the loss of harmonic information, traditional harmonic controllers fail to mitigate the grid current distortion. Although this problem may be avoided using the grid voltage feedforward scheme, the required differentiators may...... cause noise amplification. In light of the above issue, this paper develops a simple method for the ICF control system to mitigate the grid current harmonics without extra sensors. In the proposed method, resonant harmonic controllers and an additional compensation loop are adopted at the same time......LCL filters feature low inductance; thus, the injected grid current from an LCL-filtered Voltage Source Inverter (VSI) can be easily distorted by grid voltage harmonics. This problem is especially tough for the control system with Inverter-side Current Feedback (ICF), since the grid current...

  18. Advanced Stirling Radioisotope Generator Life Certification Plan

    Science.gov (United States)

    Rusick, Jeffrey J.; Zampino, Edward J.

    2013-01-01

    An Advanced Stirling Radioisotope Generator (ASRG) power supply is being developed by the Department of Energy (DOE) in partnership with NASA for potential future deep space science missions. Unlike previous radioisotope power supplies for space exploration, such as the passive MMRTG used recently on the Mars Curiosity rover, the ASRG is an active dynamic power supply with moving Stirling engine mechanical components. Due to the long life requirement of 17 years and the dynamic nature of the Stirling engine, the ASRG project faced some unique challenges trying to establish full confidence that the power supply will function reliably over the mission life. These unique challenges resulted in the development of an overall life certification plan that emphasizes long-term Stirling engine test and inspection when analysis is not practical. The ASRG life certification plan developed is described.

  19. Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations

    Science.gov (United States)

    Seoane, F.; Macías, R.; Bragós, R.; Lindecrantz, K.

    2011-11-01

    In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency.

  20. Visualization of Radioisotope Detectability Over Time.

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Brady [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    A radioactive isotope is an atom that has an unstable nucleus. The isotope can undergo radioactive decay, the process in which excessive nuclear energy is emitted from the nucleus in many different forms, such as gamma radiation, alpha particles, or beta particles. The important thing to note is that these emissions act as a signature for the isotope. Each radioisotope has a particular emission spectrum, emitting radiation at different energies and at different rates.

  1. Spatial localization of sources in the rat subthalamic motor region using an inverse current source density method

    NARCIS (Netherlands)

    van Dijk, Kees Joab; Janssen, Marcus L.F.; Zwartjes - de Klerk, D.G.M; Temel, Yasin; Visser-Vandewalle, Veerle; Veltink, Petrus H.; Benazzouz, Abdelhamid; Heida, Tjitske

    2016-01-01

    Objective: In this study we introduce the use of the current source density (CSD) method as a way to visualize the spatial organization of evoked responses in the rat subthalamic nucleus (STN) at fixed time stamps resulting from motor cortex stimulation. This method offers opportunities to visualize

  2. Method and system for a gas tube-based current source high voltage direct current transmission system

    Energy Technology Data Exchange (ETDEWEB)

    She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

    2017-08-29

    A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

  3. The effect of current and relevant information sources on the use of ...

    African Journals Online (AJOL)

    The hypotheses testing were conducted at 0.05 level of significance (p<0.05) for rejection or retention. The currency and relevance of information sources therefore have significant relationship with the use of library services. Recommended adequate funding to acquire current and relevant information sources as well as the ...

  4. the effect of current and relevant information sources on the use of ...

    African Journals Online (AJOL)

    Admin

    The hypotheses testing were conducted at. 0.05 level of significance (p<0.05) for rejection or retention. The currency and relevance of information sources therefore have significant relationship with the use of library services. Recommended adequate funding to acquire current and relevant information sources as well as ...

  5. Current source enhancements in Electrical Impedance Spectroscopy (EIS) to cancel unwanted capacitive effects

    Science.gov (United States)

    Zarafshani, Ali; Bach, Thomas; Chatwin, Chris; Xiang, Liangzhong; Zheng, Bin

    2017-03-01

    Electrical Impedance Spectroscopy (EIS) has emerged as a non-invasive imaging modality to detect and quantify functional or electrical properties related to the suspicious tumors in cancer screening, diagnosis and prognosis assessment. A constraint on EIS systems is that the current excitation system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIS is an ill-posed inverse problem which depends on the noise level in EIS measured data and regularization parameter in the reconstruction algorithm. There is high complexity in the design of stable current sources, with stray capacitance reducing the output impedance and bandwidth of the system. To confront this, we have designed an EIS current source which eliminates the effect of stray capacitance and other impacts of the capacitance via a variable inductance. In this paper, we present a combination of operational CCII based on a generalized impedance converter (OCCII-GIC) with a current source. The aim of this study is to use the EIS system as a biomedical imaging technique, which is effective in the early detection of breast cancer. This article begins with the theoretical description of the EIS structure, current source topologies and proposes a current conveyor in application of a Gyrator to eliminate the current source limitations and its development followed by simulation and experimental results. We demonstrated that the new design could achieve a high output impedance over a 3MHz frequency bandwidth when compared to other types of GIC circuits combined with an improved Howland topology.

  6. Comparison of a new integrated current source with the modified Howland circuit for EIT applications.

    Science.gov (United States)

    Hong, Hongwei; Rahal, Mohamad; Demosthenous, Andreas; Bayford, Richard H

    2009-10-01

    Multi-frequency electrical impedance tomography (MF-EIT) systems require current sources that are accurate over a wide frequency range (1 MHz) and with large load impedance variations. The most commonly employed current source design in EIT systems is the modified Howland circuit (MHC). The MHC requires tight matching of resistors to achieve high output impedance and may suffer from instability over a wide frequency range in an integrated solution. In this paper, we introduce a new integrated current source design in CMOS technology and compare its performance with the MHC. The new integrated design has advantages over the MHC in terms of power consumption and area. The output current and the output impedance of both circuits were determined through simulations and measurements over the frequency range of 10 kHz to 1 MHz. For frequencies up to 1 MHz, the measured maximum variation of the output current for the integrated current source is 0.8% whereas for the MHC the corresponding value is 1.5%. Although the integrated current source has an output impedance greater than 1 MOmega up to 1 MHz in simulations, in practice, the impedance is greater than 160 kOmega up to 1 MHz due to the presence of stray capacitance.

  7. Information parameters for realization of adaptive charge of secondary chemical sources of a current

    Directory of Open Access Journals (Sweden)

    Zhitnik N. E.

    2008-10-01

    Full Text Available A chrono-potentiometric method of control of the state of chemical sources of current (CSC is offered. The method allows from chrono-potentiogram (CPG, representing CSC reaction on the charge current impulse, to get practically all informative parameters, necessary for practical realization of adaptive charge.

  8. Abrupt variation in ion current with biased disk voltage in the electron cyclotron resonance ion source

    NARCIS (Netherlands)

    Taki, GS; Sarma, PR; Chakraborty, DK; Lhandari, RK; Ray, PK; Drentje, AG; Bhandari, R.K.

    The performance of the biased disk in the 6.4 GHz electron cyclotron resonance ion source at VECC, Kolkata was studied at a pressure of similar to 1 X 10(-7) Torr. We observed an abrupt variation of beam current with bias voltage. For low negative bias voltages (from 0 to -5 V) the beam current

  9. A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

    Science.gov (United States)

    Tripp, John S.; Daniels, Taumi S.

    1990-08-01

    The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

  10. A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

    Science.gov (United States)

    Tripp, John S.; Daniels, Taumi S.

    1990-01-01

    The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

  11. U.S. Space Radioisotope Power Systems and Applications: Past, Present and Future

    Science.gov (United States)

    Cataldo, Robert L.; Bennett, Gary L.

    2011-01-01

    Radioisotope power systems (RPS) have been essential to the U.S. exploration of outer space. RPS have two primary uses: electrical power and thermal power. To provide electrical power, the RPS uses the heat produced by the natural decay of a radioisotope (e.g., plutonium-238 in U.S. RPS) to drive a converter (e.g., thermoelectric elements or Stirling linear alternator). As a thermal power source the heat is conducted to whatever component on the spacecraft needs to be kept warm; this heat can be produced by a radioisotope heater unit (RHU) or by using the excess heat of a radioisotope thermoelectric generator (RTG). As of 2010, the U.S. has launched 41 RTGs on 26 space systems. These space systems have ranged from navigational satellites to challenging outer planet missions such as Pioneer 10/11, Voyager 1/2, Galileo, Ulysses, Cassini and the New Horizons mission to Pluto. In the fall of 2011, NASA plans to launch the Mars Science Laboratory (MSL) that will employ the new Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) as the principal power source. Hundreds of radioisotope heater units (RHUs) have been launched to provide warmth to Apollo 11, used to provide heating of critical components in a seismic experiment package, Pioneer 10/11, Voyager 1/2, Galileo, Cassini, Mars Pathfinder, MER rovers, etc. to provide temperature control to critical spacecraft electronics and other mechanical devices such as propulsion system propellant valves. A radioisotope (electrical) power source or system (RPS) consists of three basic elements: (1) the radioisotope heat source that provides the thermal power, (2) the converter that transforms the thermal power into electrical power and (3) the heat rejection radiator. Figure 1 illustrates the basic features of an RPS. The idea of a radioisotope power source follows closely after the early investigations of radioactivity by researchers such as Henri Becquerel (1852-1908), Marie Curie (1867-1935), Pierre Curie (1859

  12. Biocompatible, high precision, wideband, improved Howland current source with lead-lag compensation.

    Science.gov (United States)

    Tucker, A S; Fox, R M; Sadleir, R J

    2013-02-01

    The Howland current pump is a popular bioelectrical circuit, useful for delivering precise electrical currents. In applications requiring high precision delivery of alternating current to biological loads, the output impedance of the Howland is a critical figure of merit that limits the precision of the delivered current when the load changes. We explain the minimum operational amplifier requirements to meet a target precision over a wide bandwidth. We also discuss effective compensation strategies for achieving stability without sacrificing high frequency output impedance. A current source suitable for Electrical Impedance Tomography (EIT) was simulated using a SPICE model, and built to verify stable operation. This current source design had stable output impedance of 3.3 MΩ up to 200 kHz, which provides 80 dB precision for our EIT application. We conclude by noting the difficulty in measuring the output impedance, and advise verifying the plausibility of measurements against theoretical limitations.

  13. Recent progress in radioisotope production in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Le Van So [Radioisotope Dept., Nuclear Research Institute, Dalat (Viet Nam)

    1998-10-01

    This is a report on the recent progress in radioisotope production in Vietnam. Using a nuclear research reactor of 500 KW with continuous operation cycles of 100 hours a month, the production of some important radioisotopes used in nuclear medicine and research was routinely carried out. More than 80 per cent of irradiation capacity of reactor for radioisotope production were exploited. The radioactivity of more than 150 Ci of {sup 131}I, {sup 99}Mo-{sup 99m}Tc, {sup 32}P, {sup 51}Cr, {sup 153}Sm, {sup 46}Sc, {sup 192}Ir was produced annually. Radiopharmaceuticals such as {sup 131}I-Hippuran and in-vivo Kits for {sup 99m}Tc labelling were also prepared routinely and regularly. More than 10 in-vivo Kits including modern radiopharmaceuticals such as HmPAO kit were supplied to hospitals in Vietnam. The research on the improvement of dry distillation technology for production of {sup 131}I was carried out. As a result obtained a new distillation apparatus made from glass was successfully put to routine use in place of expensive quartz distillation furnace. We have also continued the research programme on the development of {sup 99m}Tc generators using low power research reactors. Gel technology using Zr- and Ti- molybdate gel columns for {sup 99m}Tc generator production was developed and improved continually. Portable {sup 99m}Tc generator using Zr-({sup 99}Mo) molybdate gel column and ZISORB adsorbent column for {sup 99m}Tc concentration were developed. The ZISORB adsorbent of high adsorption capacity for {sup 99}Mo and other parent radionuclides was also studied for the development purpose of alternative technology of {sup 99m}Tc and other different radionuclide generator systems. The studies on the preparation of therapeutic radiopharmaceuticals labelling with {sup 153}Sm and {sup 131}I such as {sup 153}Sm-EDTMP, {sup 131}I-MIBG were carried out. (author)

  14. The differential Howland current source with high signal to noise ratio for bioimpedance measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jinzhen; Li, Gang; Lin, Ling, E-mail: linling@tju.edu.cn [State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, People' s Republic of China, and Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin (China); Qiao, Xiaoyan [College of Physics and Electronic Engineering, Shanxi University, Shanxi (China); Wang, Mengjun [School of Information Engineering, Hebei University of Technology, Tianjin (China); Zhang, Weibo [Institute of Acupuncture and Moxibustion China Academy of Chinese Medical Sciences, Beijing (China)

    2014-05-15

    The stability and signal to noise ratio (SNR) of the current source circuit are the important factors contributing to enhance the accuracy and sensitivity in bioimpedance measurement system. In this paper we propose a new differential Howland topology current source and evaluate its output characters by simulation and actual measurement. The results include (1) the output current and impedance in high frequencies are stabilized after compensation methods. And the stability of output current in the differential current source circuit (DCSC) is 0.2%. (2) The output impedance of two current circuits below the frequency of 200 KHz is above 1 MΩ, and below 1 MHz the output impedance can arrive to 200 KΩ. Then in total the output impedance of the DCSC is higher than that of the Howland current source circuit (HCSC). (3) The SNR of the DCSC are 85.64 dB and 65 dB in the simulation and actual measurement with 10 KHz, which illustrates that the DCSC effectively eliminates the common mode interference. (4) The maximum load in the DCSC is twice as much as that of the HCSC. Lastly a two-dimensional phantom electrical impedance tomography is well reconstructed with the proposed HCSC. Therefore, the measured performance shows that the DCSC can significantly improve the output impedance, the stability, the maximum load, and the SNR of the measurement system.

  15. The differential Howland current source with high signal to noise ratio for bioimpedance measurement system

    Science.gov (United States)

    Liu, Jinzhen; Qiao, Xiaoyan; Wang, Mengjun; Zhang, Weibo; Li, Gang; Lin, Ling

    2014-05-01

    The stability and signal to noise ratio (SNR) of the current source circuit are the important factors contributing to enhance the accuracy and sensitivity in bioimpedance measurement system. In this paper we propose a new differential Howland topology current source and evaluate its output characters by simulation and actual measurement. The results include (1) the output current and impedance in high frequencies are stabilized after compensation methods. And the stability of output current in the differential current source circuit (DCSC) is 0.2%. (2) The output impedance of two current circuits below the frequency of 200 KHz is above 1 MΩ, and below 1 MHz the output impedance can arrive to 200 KΩ. Then in total the output impedance of the DCSC is higher than that of the Howland current source circuit (HCSC). (3) The SNR of the DCSC are 85.64 dB and 65 dB in the simulation and actual measurement with 10 KHz, which illustrates that the DCSC effectively eliminates the common mode interference. (4) The maximum load in the DCSC is twice as much as that of the HCSC. Lastly a two-dimensional phantom electrical impedance tomography is well reconstructed with the proposed HCSC. Therefore, the measured performance shows that the DCSC can significantly improve the output impedance, the stability, the maximum load, and the SNR of the measurement system.

  16. Analysis of a Radioisotope Thermal Rocket Engine

    Science.gov (United States)

    Machado-Rodriguez, Jonathan P.; Landis, Geoffrey A.

    2017-01-01

    The Triton Hopper is a concept for a vehicle to explore the surface of Neptunes moon Triton, which uses a radioisotope heated rocket engine and in-situ propellant acquisition. The initial Triton Hopper conceptual design stores pressurized Nitrogen in a spherical tank to be used as the propellant. The aim of the research was to investigate the benefits of storing propellant at ambient temperature and heating it through a thermal block during engine operation, as opposed to storing gas at a high temperature.

  17. Conical Current Sheets in a Source-Surface Model of the Heliosphere

    Science.gov (United States)

    Schulz, M.

    2007-12-01

    Different methods of modeling the coronal and heliospheric magnetic field are conveniently visualized and intercompared by applying them to ideally axisymmetric field models. Thus, for example, a dipolar B field with its moment parallel to the Sun's rotation axis leads to a flat heliospheric current sheet. More general solar B fields (still axisymmetric about the solar rotation axis for simplicity) typically lead to cone-shaped current sheets beyond the source surface (and presumably also in MHD models). As in the dipolar case [Schulz et al., Solar Phys., 60, 83-104, 1978], such conical current sheets can be made realistically thin by taking the source surface to be non-spherical in a way that reflects the underlying structure of the Sun's main B field. A source surface that seems to work well in this respect [Schulz, Ann. Geophysicae, 15, 1379-1387, 1997] is a surface of constant F = (1/r)kB, where B is the scalar strength of the Sun's main magnetic field and k (~ 1.4) is a shape parameter. This construction tends to flatten the source surface in regions where B is relatively weak. Thus, for example, the source surface for a dipolar B field is shaped somewhat like a Rugby football, whereas the source surface for an axisymmetric quadrupolar B field is similarly elongated but somewhat flattened (as if stuffed into a cone) at mid-latitudes. A linear combination of co-axial dipolar and quadrupolar B fields generates a somewhat pear-shaped (but still convex) source surface. If the region surrounded by the source surface is regarded as current-free, then the source surface itself should be (as nearly as possible) an equipotential surface for the corresponding magnetic scalar potential (expanded, for example, in spherical harmonics). The solar wind should then flow not quite radially, but rather in a straight line along the outward normal to the source surface, and the heliospheric B field should follow a corresponding generalization of Parker's spiral [Levine et al

  18. A HIGH CURRENT DENSITY LI+ ALUMINO-SILICATE ION SOURCE FOR TARGET HEATING EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.

    2011-03-23

    The NDCX-II accelerator for target heating experiments has been designed to use a large diameter ({approx_equal} 10.9 cm) Li{sup +} doped alumino-silicate source with a pulse duration of 0.5 {micro}s, and beam current of {approx_equal} 93 mA. Characterization of a prototype lithium alumino-silicate sources is presented. Using 6.35mm diameter prototype emitters (coated on a {approx_equal} 75% porous tungsten substrate), at a temperature of {approx_equal} 1275 C, a space-charge limited Li{sup +} beam current density of {approx_equal} 1 mA/cm{sup 2} was measured. At higher extraction voltage, the source is emission limited at around {approx_equal} 1.5 mA/cm{sup 2}, weakly dependent on the applied voltage. The lifetime of the ion source is {approx_equal} 50 hours while pulsing the extraction voltage at 2 to 3 times per minute. Measurements show that the life time of the ion source does not depend only on beam current extraction, and lithium loss may be dominated by neutral loss or by evaporation. The life time of a source is around {ge} 10 hours in a DC mode extraction, and the extracted charge is {approx_equal} 75% of the available Li in the sample. It is inferred that pulsed heating may increase the life time of a source.

  19. Low power current sources for bioimpedance measurements: A comparison between Howland and integrated CMOS OTA circuits

    Directory of Open Access Journals (Sweden)

    Pedro Bertemes-Filho

    2012-10-01

    Full Text Available Electrical Bioimpedance Analysis has been widely used as a non-invasive technique for characterizing tissues. Most systems use a wideband and a high precision instrumentation, specially the current source. The objective of this work is to compare the Howland circuit with three OTA-based floating voltage controlled current sources. The results show that both Current Conveyor and class-AB OTA have a wider output current frequency response and both output impedance is 226 % bigger than the Howland circuit at 1 MHz. The class-AB OTA circuit presents a power consumption of 4.6 mW whereas 1.6 mW for the Current Conveyor. The results might be useful for cell impedance measurements and for very low power bioimpedance applications.

  20. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.

    2008-01-01

    This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches......, resulting in the natural balance of input current. For maintaining the normalized volt-sec average unchanged, the alternative phase opposition disposition (APOD) modulation scheme with typical gating signal mapping technique from voltage source inverter (VSI) to CSI can be assumed to control the five......-level buck-boost CSIs. Next by observing the hidden current charging path during inductive charging interval under APOD modulation, it is noted that the buck-boost five-level CSI can then be further modified with lesser active component without degrading output performance. To verify the theoretical findings...

  1. Design of current source for multi-frequency simultaneous electrical impedance tomography

    Science.gov (United States)

    Han, Bing; Xu, Yanbin; Dong, Feng

    2017-09-01

    Multi-frequency electrical impedance tomography has been evolving from the frequency-sweep approach to the multi-frequency simultaneous measurement technique which can reduce measuring time and will be increasingly attractive for time-varying biological applications. The accuracy and stability of the current source are the key factors determining the quality of the image reconstruction. This article presents a field programmable gate array-based current source for a multi-frequency simultaneous electrical impedance tomography system. A novel current source circuit was realized by combining the classic current mirror based on the feedback amplifier AD844 with a differential topology. The optimal phase offsets of harmonic sinusoids were obtained through the crest factor analysis. The output characteristics of this current source were evaluated by simulation and actual measurement. The results include the following: (1) the output impedance was compared with one of the Howland pump circuit in simulation, showing comparable performance at low frequencies. However, the proposed current source makes lower demands for resistor tolerance but performs even better at high frequencies. (2) The output impedance in actual measurement below 200 kHz is above 1.3 MΩ and can reach 250 KΩ up to 1 MHz. (3) An experiment based on a biological RC model has been implemented. The mean error for the demodulated impedance amplitude and phase are 0.192% and 0.139°, respectively. Therefore, the proposed current source is wideband, biocompatible, and high precision, which demonstrates great potential to work as a sub-system in the multi-frequency electrical impedance tomography system.

  2. Temperature dependence of the current in Schottky-barrier source-gated transistors

    Science.gov (United States)

    Sporea, R. A.; Overy, M.; Shannon, J. M.; Silva, S. R. P.

    2015-05-01

    The temperature dependence of the drain current is an important parameter in thin-film transistors. In this paper, we propose that in source-gated transistors (SGTs), this temperature dependence can be controlled and tuned by varying the length of the source electrode. SGTs comprise a reverse biased potential barrier at the source which controls the current. As a result, a large activation energy for the drain current may be present which, although useful in specific temperature sensing applications, is in general deleterious in many circuit functions. With support from numerical simulations with Silvaco Atlas, we describe how increasing the length of the source electrode can be used to reduce the activation energy of SGT drain current, while maintaining the defining characteristics of SGTs: low saturation voltage, high output impedance in saturation, and tolerance to geometry variations. In this study, we apply the dual current injection modes to obtain drain currents with high and low activation energies and propose mechanisms for their exploitation in future large-area integrated circuit designs.

  3. Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This paper presents new five-level current-source inverters (CSIs) with voltage/current buck–boost capability, unlike existing five-level CSIs where only voltage–boost operation is supported. The proposed inverters attain self-inductive-currentbalancing per switching cycle at their dc front ends...... without having to include additional balancing hardware or complex control manipulation. The inverters can conveniently be controlled by using the well-established phase-shifted carrier modulation scheme with only two additional linear references and a mapping logic table needed. Existing modulators can...... therefore be conveniently retrofitted for controlling the presented inverters. By appropriately coordinating the inverter gating signals, their implementations can be realized by using the least number of components without degrading performance. These enhanced features of the inverters have already been...

  4. Change of X-ray intensity in reference spectrometric gamma sources. [Radioisotopes: /sup 54/Mn, /sup 57/Co, /sup 65/Zn, /sup 88/Y, /sup 113/Sn, /sup 137/Cs, /sup 139/Ce, /sup 203/Hg, /sup 241/Am

    Energy Technology Data Exchange (ETDEWEB)

    Vylov, Ts.; Gromov, K.Ya.; Brudanin, V.B.; Matveev, S.V.; Stepanov, Eh.K.

    1982-04-01

    The results of investigations of effects influencing on the intensity of low-enegry ..gamma..- and X-radiations of reference spectrometric ..gamma..-sources (RSGS) are presented. The investigations have been performed with the aid of Ge(Li)-spectrometer. It has been found that quantum absorption in a polyethylene protective film constitutes less than 1% A /1% at the energy over 14 keV. The effect resulting from backscattering from the polyethylene film is negligibly small, whereas the increase in thickness and atomic number of substrate leads to continuous distribution distortion in the field of the spectrum line and therefore to ambiguous choice of background parameters in the course of computer spectrum unfolding. The self absorption in the source and absorption in the air layer between the detector inlet window and the source are evaluated. The conclusion is drawn on the usability of RSGS for calibrating semiconductor spectrometers by recording efficiency, when the energy is 14 keV and above.

  5. Evaluation of Resonant Damping Techniques for Z-Source Current-Type Inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gajanayake, C.J.

    2008-01-01

    For the renewable energy sources whose outputs vary continuously, a Z-source current-type inverter has been proposed as a possible buck-boost alternative for grid-interfacing. With a unique X-shaped LC network connected between its dc power source and inverter topology, Z-source current......-type inverter is however expected to suffer from compounded resonant complications in addition to those associated with its second-order output filter. To improve its damping performance, this paper proposes the careful integration of Posicast or three-step compensators before the inverter pulse-width modulator...... for damping triggered resonant oscillations. In total, two compensators are needed for wave-shaping the inverter boost factor and modulation ratio, and they can conveniently be implemented using first-in first-out stacks and embedded timers of modern digital signal processors widely used in motion control...

  6. Conditioning a current source using OCCII-GIC for EIT systems

    OpenAIRE

    Zarafshani, Ali; Bach, Tom; Wang, Wei; Chatwin, Chris

    2015-01-01

    Multi-Frequency EIT has been developed to evaluate the permittivity spectrum of a medium using an improved Howland source. Stray capacitance reduces the output impedance, bandwidth of the data collection leading to erroneous measurements. To address this, we have designed a current source, which uses a novel OCCII - GIC to cancel stray capacitance. The system achieves high output impedance over a 5 MHz frequency range.

  7. Solar quiet day ionospheric source current in the West African region

    OpenAIRE

    Theresa N. Obiekezie; Okeke, Francisca N.

    2013-01-01

    The Solar Quiet (Sq) day source current were calculated using the magnetic data obtained from a chain of 10 magnetotelluric stations installed in the African sector during the French participation in the International Equatorial Electrojet Year (IEEY) experiment in Africa. The components of geomagnetic field recorded at the stations from January–December in 1993 during the experiment were separated into the source and (induced) components of Sq using Spherical Harmonics Analysis (SHA) method....

  8. A low-voltage, high-current, ion-bombardment source using magnetron principles

    Energy Technology Data Exchange (ETDEWEB)

    Ja' fer, H.A.; Howson, R.P. (Loughborough Univ of Technology (United Kingdom). Dept. of Physics)

    The operation of an unbalanced magnetron under conditions using extra electron injection is shown to be a source of plasma beam which can give a substrate a self-bias of between 25 and 100 V, and allow total ion-currents of over one ampere to be drawn to a target. The use of the device to give low-energy, ion-bombardment of a growing films and to form a dense plasma source for low voltage sputtering is reported. (Author).

  9. High purity materials as targets for radioisotope production: Needs ...

    Indian Academy of Sciences (India)

    Artificial transmutation of an element employing thermal neutrons in a reactor or high energy particle accelerators (cyclotrons) are the routes of radioisotope production world over. Availability of high purity target materials, natural or enriched, are crucial for any successful radioisotope programme. Selection of stable ...

  10. Polyatomic ions from a high current ion implanter driven by a liquid metal ion source.

    Science.gov (United States)

    Pilz, W; Laufer, P; Tajmar, M; Böttger, R; Bischoff, L

    2017-12-01

    High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi 2 + ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

  11. Current State of Research of Alternate Fuel Sources for Passenger Vehicles

    Science.gov (United States)

    Massey, Lee

    2008-03-01

    The purpose of this project is to report on the current state of research in the field of alternate fuel sources for passenger vehicles. Because the number of alternate fuel options is very large, this study focuses on selected bio-fuels and briefly describes a couple of the most popular non-bio and non-renewable alternatives. The fuel and energy sources studied are compared using well-to-wheel and well-to-tank net energy balances. Data also includes relative production capabilities by volume in terms of current fossil fuels. Qualitative data includes production methods and transportability.

  12. Note: Temperature effects in the modified Howland current source for electrical bioimpedance spectroscopy

    Science.gov (United States)

    Fernandez Santos, S.; Bertemes-Filho, P.

    2017-07-01

    The aim of this study is to show how the modified Howland current source (MHCS) is affected by temperature changes. The source has been tested in a temperature range from 20 to 70 °C and frequency range from 100 Hz to 1 MHz. Parameters like output current, output impedance, total harmonic distortion, and oscillation have been measured. The measurements were made inside a temperature controlled environment. It was showed that the MHCS is stable at temperatures below 70 °C. Operational amplifiers with a low temperature drift and matching resistor should be carefully considered in order to prevent oscillations at high temperatures.

  13. Current status and future perspectives of accelerator-based x-ray light sources

    Science.gov (United States)

    Tanaka, Takashi

    2017-09-01

    State-of-the-art x-ray light sources are nowadays based on large-scale electron accelerators, because the synchrotron radiation (SR) and x-ray free electron laser (XFEL) radiation generated by high-energy electron beams have many advantages over other alternatives in terms of the wavelength tunability, high brightness and flux, high coherence, flexible polarization states, and so on. This is the reason why SR and XFEL light sources have largely contributed to the evolution of x-ray science. This paper reviews the current status of such accelerator-based x-ray light source facilities and discusses their future perspectives.

  14. Ionospheric current source modeling and global geomagnetic induction using ground geomagnetic observatory data

    Science.gov (United States)

    Sun, Jin; Kelbert, Anna; Egbert, G.D.

    2015-01-01

    Long-period global-scale electromagnetic induction studies of deep Earth conductivity are based almost exclusively on magnetovariational methods and require accurate models of external source spatial structure. We describe approaches to inverting for both the external sources and three-dimensional (3-D) conductivity variations and apply these methods to long-period (T≥1.2 days) geomagnetic observatory data. Our scheme involves three steps: (1) Observatory data from 60 years (only partly overlapping and with many large gaps) are reduced and merged into dominant spatial modes using a scheme based on frequency domain principal components. (2) Resulting modes are inverted for corresponding external source spatial structure, using a simplified conductivity model with radial variations overlain by a two-dimensional thin sheet. The source inversion is regularized using a physically based source covariance, generated through superposition of correlated tilted zonal (quasi-dipole) current loops, representing ionospheric source complexity smoothed by Earth rotation. Free parameters in the source covariance model are tuned by a leave-one-out cross-validation scheme. (3) The estimated data modes are inverted for 3-D Earth conductivity, assuming the source excitation estimated in step 2. Together, these developments constitute key components in a practical scheme for simultaneous inversion of the catalogue of historical and modern observatory data for external source spatial structure and 3-D Earth conductivity.

  15. Current Harmonics Compensation in Microgrids Exploiting the Power Electronics Interfaces of Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    Ioannis Bouloumpasis

    2015-03-01

    Full Text Available This work presents a method of current harmonic reduction in a distorted distribution system. In order to evaluate the proposed method a grid with high-order current harmonics is assumed. The reduction of current distortion is feasible due to the pulse modulation of an active filter, which consists of a buck-boost converter connected back-to-back to a polarity swapping inverter. For a practical application, this system would be the power electronic interface of a Renewable Energy Source (RES and therefore it changes a source of harmonics to a damping harmonics system. Using the proposed method, the current Total Harmonic Distortion (THD of the grid is reduced below the acceptable limits and thus the general power quality of the system is improved. Simulations in the MATLAB/SIMULINK platform and experiments have been performed in order to verify the effectiveness of the proposed method.

  16. Assessment of radioisotope heaters for remote terrestrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Uherka, K.L.

    1987-05-01

    This paper examines the feasibility of using radioisotope byproducts for special heating applications at remote sites in Alaska and other cold regions. The investigation included assessment of candidate radioisotope materials for heater applications, identification of the most promising cold region applications, evaluation of key technical issues and implementation constraints, and development of conceptual heater designs for candidate applications. Strontium-90 (Sr-90) was selected as the most viable fuel for radioisotopic heaters used in terrestrial applications. Opportunities for the application of radioisotopic heaters were determined through site visits to representative Alaska installations. Candidate heater applications included water storage tanks, sludge digesters, sewage lagoons, water piping systems, well-head pumping stations, emergency shelters, and fuel storage tank deicers. Radioisotopic heaters for water storage tank freeze-up protection and for enhancement of biological waste treatment processes at remote sites were selected as the most promising applications.

  17. A Single-to-Three Phase PWM Current Source Converter with Four Legs

    Science.gov (United States)

    Neba, Yasuhiko; Matsumoto, Hirokazu; Itoh, Ryozo; Ishizaka, Kouichi

    A current source converter between single-phase and three-phase are presented. The converter circuit consists of four legs with eight switching devices. The PWM strategies with the sinusoidal modulating wave and the triangular carrier wave are employed for sinusoidal waves in ac sides. The selection of the device to obtain the sinusoidal PWM controlled current is shown and the switching patterns are given.

  18. Pathway of radioisotopes from land surface to sewage sludge

    Science.gov (United States)

    Fischer, Helmut W.; Yokoo, Yoshiyuki

    2014-05-01

    Radioactive surface contaminations will only partially remain at the original location - a fraction of the inventory will take part in (mainly terrestrial and aquatic) environmental transport processes. The probably best known and most important process comprises the food chain. Besides, the translocation of dissolved and particle-bound radioisotopes with surface waters plays an important role. These processes can have the effect of displacing large radioisotope amounts over considerable distances and of creating new sinks and hot spots, as it is already known for sewage sludge. We are reporting on a combined modeling and experimental project concerning the transport of I-131 and Cs-134/Cs-137 FDNPP 2011 depositions in the Fukushima Prefecture. Well-documented experimental data sets are available for surface deposition and sewage sludge concentrations. The goal is to model the pathway in between, involving surface runoff, transport in the sewer system and processes in the sewage treatment plant. Watershed runoff and sewer transport will be treated with models developed recently by us in other projects. For sewage treatment processes a new model is currently being constructed. For comparison and further validation, historical data from Chernobyl depositions and tracer data from natural and artificial, e.g. medical, isotopes will be used. First results for 2011 data from Fukushima Prefecture will be presented. The benefits of the study are expected to be two-fold: on one hand, the abundant recent and historical data will help to develop and improve environmental transport models; on the other hand, both data and models will help in identifying the most critical points in the envisaged transport pathways in terms of radiation protection and waste management.

  19. Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    Shoudao Huang

    2016-09-01

    Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

  20. Integro-differential equation analysis and radioisotope imaging systems. Research proposal. [Testing of radioisotope imaging system in phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Hart, H.

    1976-03-09

    Design modifications of a five-probe focusing collimator coincidence radioisotope scanning system are described. Clinical applications of the system were tested in phantoms using radioisotopes with short biological half-lives, including /sup 75/Se, /sup 192/Ir, /sup 43/K, /sup 130/I, and /sup 82/Br. Data processing methods are also described. (CH)

  1. Current use of imaging and electromagnetic source localization procedures in epilepsy surgery centers across Europe

    NARCIS (Netherlands)

    Mouthaan, Brian E|info:eu-repo/dai/nl/413967794; Rados, Matea|info:eu-repo/dai/nl/413970485; Barsi, Péter; Boon, Paul; Carmichael, David W; Carrette, Evelien; Craiu, Dana; Cross, J Helen; Diehl, Beate; Dimova, Petia; Fabo, Daniel; Francione, Stefano; Gaskin, Vladislav; Gil-Nagel, Antonio; Grigoreva, Elena; Guekht, Alla; Hirsch, Edouard; Hecimovic, Hrvoje; Helmstaedter, Christoph; Jung, Julien; Kalviainen, Reetta; Kelemen, Anna; Kimiskidis, Vasilios; Kobulashvili, Teia; Krsek, Pavel; Kuchukhidze, Giorgi; Larsson, Pål G; Leitinger, Markus; Lossius, Morten I; Luzin, Roman; Malmgren, Kristina; Mameniskiene, Ruta; Marusic, Petr; Metin, Baris; Özkara, Cigdem; Pecina, Hrvoje; Quesada, Carlos M; Rugg-Gunn, Fergus; Rydenhag, Bertil; Ryvlin, Philippe; Scholly, Julia; Seeck, Margitta; Staack, Anke M; Steinhoff, Bernhard J; Stepanov, Valentin; Tarta-Arsene, Oana; Trinka, Eugen; Uzan, Mustafa; Vogt, Viola L; Vos, Sjoerd B; Vulliémoz, Serge; Huiskamp, Geertjan|info:eu-repo/dai/nl/074463640; Leijten, Frans S S|info:eu-repo/dai/nl/152243054; Van Eijsden, Pieter; Braun, Kees P J|info:eu-repo/dai/nl/207237239

    2016-01-01

    OBJECTIVE: In 2014 the European Union-funded E-PILEPSY project was launched to improve awareness of, and accessibility to, epilepsy surgery across Europe. We aimed to investigate the current use of neuroimaging, electromagnetic source localization, and imaging postprocessing procedures in

  2. Source brightness and useful beam current of carbon nanotubes and other very small emitters

    NARCIS (Netherlands)

    Kruit, P.; Bezuijen, M.; Barth, J.E.

    2006-01-01

    The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky

  3. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  4. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga.vadim@gmail.com [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Sidorov, A. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Maslennikova, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State Medical Academy, 10/1 Minina Sq., 603005 Nizhny Novgorod (Russian Federation); Volovecky, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Tarvainen, O. [University of Jyvaskyla, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2014-12-21

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm{sup 2} is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·10{sup 10} cm{sup −2}/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  5. Current State and Future Perspectives of Energy Sources for Totally Implantable Cardiac Devices.

    Science.gov (United States)

    Bleszynski, Peter A; Luc, Jessica G Y; Schade, Peter; PhilLips, Steven J; Tchantchaleishvili, Vakhtang

    There is a large population of patients with end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. Implantable cardiac devices, many designated as destination therapy, have revolutionized patient care and outcomes, although infection and complications related to external power sources or routine battery exchange remain a substantial risk. Complications from repeat battery replacement, power failure, and infections ultimately endanger the original objectives of implantable biomedical device therapy - eliminating the intended patient autonomy, affecting patient quality of life and survival. We sought to review the limitations of current cardiac biomedical device energy sources and discuss the current state and trends of future potential energy sources in pursuit of a lifelong fully implantable biomedical device.

  6. Assembly and Testing of a Radioisotope Power System for the New Horizons Spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth E. Rosenberg; Stephen G. Johnson

    2006-06-01

    The Idaho National Laboratory (INL) recently fueled and assembled a radioisotope power system (RPS) that was used upon the New Horizons spacecraft which was launched in January 2006. New Horizons is the first mission to the last planet - the initial reconnaissance of Pluto-Charon and the Kuiper Belt, exploring the mysterious worlds at the edge of our solar system. The RPS otherwise known as a "space battery" converts thermal heat into electrical energy. The thermal heat source contains plutonium dioxide in the form of ceramic pellets encapsulated in iridium metal. The space battery was assembled in a new facility at the Idaho National Laboratory site near Idaho Falls, Idaho. The new facility has all the fueling and testing capabilities including the following: the ability to handle all the shipping containers currently certified to ship Pu-238, the ability to fuel a variety of RPS designs, the ability to perform vibrational testing to simulate transportation and launch environments, welding systems, a center of mass determination device, and various other support systems.

  7. Development of leakage monitoring system using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. C.; Lee, D. S. [Seoil College, Seoul (Korea); Cho, Y. S. [Konyang University, Nonsan (Korea); Shin, S. K. [Sungkyunkwan Univ., Seoul (Korea)

    2000-04-01

    This study is to development the potable neutron back-scattering gauge for leakage and detecting liquid interface of an oil and liquid tank, using a radioisotopes. For this purpose, small sized, light weight potable gauge is to be designed as to develope neutron shielding mechanism, low power supply circuit, high voltage circuit, measurement circuit, and operating handle etc. The user will be able to set the duration of the time interval, the scale, the high voltage, the threshold, the channel window, the selection whether the data storage or not, the selection whether the scale, high voltage, threshold and window fix or not at any time. The counted pulse will be displayed with the numerical value and the line bar. The gauge will be able to connect to an IBM compatible PC via a serial port, power will be supplied by internal battery. 9 refs., 28 figs., 10 tabs. (Author)

  8. Radioisotope Power Systems Program Status and Expectations

    Science.gov (United States)

    Zakrajsek, June F.; Hamley, John A.; Sutliff, Thomas J.; Mccallum, Peter W.; Sandifer, Carl E.

    2017-01-01

    The Radioisotope Power Systems (RPS) Programs goal is to make RPS available for the exploration of the solar system in environments where conventional solar or chemical power generation is impractical or impossible to use to meet mission needs. To meet this goal, the RPS Program manages investments in RPS system development and RPS technologies. The RPS Program exists to support NASA's Science Mission Directorate (SMD). The RPS Program provides strategic leadership for RPS, enables the availability of RPS for use by the planetary science community, successfully executes RPS flight projects and mission deployments, maintains a robust technology development portfolio, manages RPS related National Environmental Policy Act (NEPA) and Nuclear Launch Safety (NLS) approval processes for SMD, maintains insight into the Department of Energy (DOE) implementation of NASA funded RPS production infrastructure operations, including implementation of the NASA funded Plutonium-238 production restart efforts. This paper will provide a status of recent RPS activities.

  9. Recent progress in development of radioisotope production

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Byung Mok [HANARO Center, Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-10-01

    The Korea multipurpose research reactor, HANARO(Hi-flux Advanced Neutron Application Reactor) is designed and constructed to obtain high density neutron flux (max. 5x10{sup 14} n/cm{sup 2}{center_dot}sec) with relatively low thermal output (30 MW) in order to utilize for various studies such as fuel and material test, radioisotope production, neutron activation analysis, neutron beam experiment, neutron transmutation doping, etc. HANARO has 32 vertical channels (3 in-core, 4 out-core, 25 reflector) and 7 horizontal channels. KAERI has constructed 4 concrete hot cells for production of Co-60, Ir-192, etc. and 6 lead hot cells for production of medical RIs(I-131, Mo-99, etc.). Other 11 lead hot cells will be completed by Feb. 1998 for production of Sm-153, Dy-165, Ho-166, etc. Clean room facilities were installed for production of radiopharmaceuticals. (author)

  10. Current source converter based D-STATCOM for voltage sag mitigation

    Directory of Open Access Journals (Sweden)

    Singh Moirangthem Deben

    2015-01-01

    Full Text Available This paper presents a novel method of realizing one of the custom power controllers, the distribution static synchronous compensator (D-STATCOM using current source converter (CSC topology. Almost all the custom power controllers such as dynamic voltage restorer (DVR, unified power quality conditioner (UPQC including D-STATCOM are generally designed and implemented by using voltage source converters (VSC and not much research publications with CSC based approach has been reported over the last one decade. Since the D-STATCOM is a current injection device, its performance can be improved when realized by a current-source converter which can generate a controllable current directly at its output terminals and offers many advantageous features. In this paper, an attempt has been made to study the performance of a CSC based D-STATCOM suitable for use in the power distribution system in order to mitigate voltage sag and improve power quality. The proposed model uses a three leg CSC whose switching strategy is based on sinusoidal pulse width modulation (SPWM. The model has been simulated in the Matlab/Simulink environment. The results of the simulation runs under steady state and dynamic load perturbation provide excellent voltage and current waveforms that support the justification of the proposed model.

  11. A programmable low power current source for bioimpedance measurement: Towards a wearable personalized health assistant.

    Science.gov (United States)

    Hamed, Zaid; Tenhunen, Hannu; Yang, Geng

    2015-01-01

    Bioimpedance is a noninvasive measurement method that facilitates body composition analysis, besides being indicative of many other health parameters. In this work a novel programmable, low complexity, high output impedance, high voltage compliance and wideband current source for bioimpedance applications is presented. Previously, we designed, fabricated and tested in vivo a bio-patch for acquisition of multiple bio-signals. Upon integration with our previous work, this circuit is envisioned to constitute part of a personalized health assistant. Simulation at worst case corners and real operation conditions was carried out using UMC-180 nm 1 poly 6 metal CMOS process. Full duty cycle, shortened or stepped square waves can be generated. Amplitude control of 8 different current levels is supported. Frequency can be tuned up to 1 MHz and an output impedance of 2.8 MO @ 250 KHz is achieved at full current capacity. Total current consumption is comparable to the injected current, making the circuit highly efficient.

  12. MECRIS A compact ECRIS for ionization of noble gas radioisotopes at ISOLDE

    CERN Document Server

    Wenander, Fredrik

    2004-01-01

    The development of electron cyclotron resonance ion source (ECRIS) for singly charged radioactive gases at ISOLDE/CERN was analyzed. The radioisotopes were produced by fission, spallation and fragmentation reactions which were induced by high-energy protons. It was observed that Mono ECRIS (MECRIS) ISOLIDE was intended for light noble gases with low ionization efficiency in ordinary plasma ion sources. The results show that ionization efficiencies for He and Xe injected through calibrated leak were less than 0.1 and 5%-10% which were similar to standard ISOLDE plasma ion source. (Edited abstract) 11 Refs.

  13. Integrated fuzzy-PI controlled current source converter based D-STATCOM

    Directory of Open Access Journals (Sweden)

    M. Deben Singh

    2016-12-01

    Full Text Available The distribution static synchronous compensator (D-STATCOM is a shunt-connected current injection custom power (CP device that can be used for improving quality and reliability of the power supplied to electric consumers under dynamic conditions of the distribution system. The CP devices such as dynamic voltage restorer and unified power quality conditioner including D-STATCOM are mostly designed and implemented using voltage source converter topology. The performance of D-STATCOM can be improved, if it is realized by using a current source converter topology which can generate a controllable current directly at its output terminals. Although the current source converter (CSC topology offers many promising advantageous features, not much research publications with CSC-based approach in the field of CP devices has been reported over the last one decade. This paper presents a novel method of realizing a D-STATCOM using CSC topology with an integrated fuzzy-PI controller for not only mitigating voltage sag but also capable of maintaining improved DC-link voltage profile. The model has been simulated in the MATLAB/SIMULINK environment. The simulation results under steady state and dynamic load perturbation provide excellent output characteristics that support the validity of the proposed model.

  14. Extracted beam and electrode currents in the inductively driven surface-plasma negative hydrogen ion source

    Science.gov (United States)

    Belchenko, Yu.; Ivanov, A.; Sanin, A.; Sotnikov, O.

    2017-08-01

    The data on long-pulsed operation of RF surface-plasma source is presented. The source regularly produces the H- ion beam with current >1A, energy ≥90 keV and pulse duration ≥2 s. The total H- beam curent, transported to the distant Faraday cup and the currents in the circuits of ion-optical system elements were measured. The composition of accelerated and extracted grid currents was clarified. The relatively high level of acceleration grid current 0.4 A was observed. It consists mainly of secondary electrons, emitted from extraction grid apertures and stripped from H- ions and could be decreased by optimization of positive PG bias applied. The test stand experiments on beam transport through the LEBT were carried out. About 90% of the H- ion beam was transported from the source to the distant calorimeter plane. The full size of 93 keV beam, transported to the calorimeter plane, was larger, than the size of the calorimeter inlet window. As a result, ˜ 60% of the initial beam power was registered by the calorimeter with window 24×24 cm2.

  15. Action-potential discharge in hippocampal CA1 pyramidal neurons: current source-density analysis.

    Science.gov (United States)

    Richardson, T L; Turner, R W; Miller, J J

    1987-11-01

    1. The site of origin of evoked action-potential discharge in hippocampal CA1 pyramidal neurons was investigated using the in vitro rat hippocampal slice preparation. 2. Action-potential discharge in pyramidal cells was evoked by stimulation of efferent pyramidal cell fibers in the alveus (antidromic) or afferent synaptic inputs in stratum oriens (SO) or stratum radiatum (SR). Laminar profiles of evoked extracellular field potentials were recorded at 25-micron intervals along the entire dendrosomatic axis of the pyramidal cell and a one-dimensional current source-density analysis was applied. 3. Suprathreshold stimulation of the alveus evoked an antidromic population spike response and current sink with the shortest peak latency in stratum pyramidale or proximal stratum oriens. A biphasic positive/negative potential associated with a current source/sink was recorded in dendritic regions, with both components increasing in peak latency with distance from the border of stratum pyramidale. 4. Suprathreshold stimulation of SO or SR evoked a population spike response superimposed upon the underlying synaptic depolarization at all levels of the dendrosomatic axis. The shortest latency population spike and current sink were recorded in stratum pyramidale or proximal stratum oriens. In dendritic regions, a biphasic positive/negative potential and current source/sink conducted with increasing latency from the border of stratum pyramidale. 5. A direct comparison of alvear- and SR-evoked responses revealed a basic similarity in population spike potentials and associated sink/source relationships at both the somatic and dendritic level and a similar shift in peak latency of spike components along the pyramidal cell axis. 6. It is concluded that the initial site for generation of a spike along the dendrosomatic axis of the pyramidal cell following antidromic or orthodromic stimulation is in the region of the cell body layer (soma or axon hillock). Action-potential discharge in

  16. Life atomic a history of radioisotopes in science and medicine

    CERN Document Server

    Creager, Angela N H

    2013-01-01

    After World War II, the US Atomic Energy Commission (AEC) began mass-producing radioisotopes, sending out nearly 64,000 shipments of radioactive materials to scientists and physicians by 1955. Even as the atomic bomb became the focus of Cold War anxiety, radioisotopes represented the government's efforts to harness the power of the atom for peace-advancing medicine, domestic energy, and foreign relations.             In Life Atomic, Angela N. H. Creager tells the story of how these radioisotopes, which were simultaneously scientific tools and political icons, transformed biomedicine and ecolog

  17. Radioisotope Reduction Using Solar Power for Outer Planetary Missions

    Science.gov (United States)

    Fincannon, James

    2008-01-01

    Radioisotope power systems have historically been (and still are) the power system of choice from a mass and size perspective for outer planetary missions. High demand for and limited availability of radioisotope fuel has made it necessary to investigate alternatives to this option. Low mass, high efficiency solar power systems have the potential for use at low outer planetary temperatures and illumination levels. This paper documents the impacts of using solar power systems instead of radioisotope power for all or part of the power needs of outer planetary spacecraft and illustrates the potential fuel savings of such an approach.

  18. Front end with offset-free symmetrical current source optimized for time domain impedance spectroscopy.

    Science.gov (United States)

    Pliquett, Uwe; Schönfeldt, Markus; Barthel, Andreas; Frense, Dieter; Nacke, Thomas; Beckmann, Dieter

    2011-07-01

    Fast impedance measurements are often performed in time domain utilizing broad bandwidth excitation signals. Other than in frequency domain measurements harmonic distortion cannot be compensated which requires careful design of the analog front end. In order to minimize the influence of electrode polarization and noise, especially in low-frequency measurements, current injection shows several advantages compared to voltage application. Here, we show an active front end based on a voltage-controlled current source for a wide range of impedances. Using proper feedback, the majority of the parasitic capacitances are compensated. The bandwidth ranges from dc to 20 MHz for impedance magnitude below 5 kΩ. The output is a symmetric signal without dc-offset which is accomplished by combination of a current conveyor and a voltage inverter. An independent feedback loop compensates the offset arising from asymmetries within the circuitry. We focused especially on the stability of the current source for usage with small metal electrodes in aqueous solutions. At the monitor side two identical, high input impedance difference amplifiers convert the net current through the object and the voltage dropping across into a 50 Ω symmetric output. The entire circuitry is optimized for step response making it suitable for fast time domain measurements.

  19. Study of problem of waste chemical current sources in Russia and in European countries

    Science.gov (United States)

    Zilenina, V. G.; Ulanova, O. V.; Dornack, C.

    2017-10-01

    This article gives a comparative analysis of handling waste chemical current sources in Russia and in the European countries, presents the effective international documents (Directives, acts) and national legislative acts (state standards, building codes, governmental decrees, etc.), demonstrates the mechanisms for disposal and recycling of waste in the European Union countries. Along with the data of the research works, conducted in other countries during many yearsб it presents the experimental data on leaching out heavy metals from chemical current sources by municipal solid waste landfill filtrate, depending on the morphological composition of domestic waste in the city of Irkutsk. An important point described in the article, is assessment and prediction of negative impact produced on the environment.

  20. Measurements of beam current density and proton fraction of a permanent-magnet microwave ion source.

    Science.gov (United States)

    Waldmann, Ole; Ludewigt, Bernhard

    2011-11-01

    A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm(2) have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parameters was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material. © 2011 American Institute of Physics

  1. Design of Programmable LED Controller with a Variable Current Source for 3D Image Display

    Directory of Open Access Journals (Sweden)

    Kyung-Ryang Lee

    2014-12-01

    Full Text Available Conventional fluorescent light sources, as well as incandescent light sources are gradually being replaced by Light Emitting Diodes (LEDs for reducing power consumption in the image display area for multimedia application. An LED light source requires a controller with a low-power operation. In this paper, a low-power technique using adiabatic operation is applied for the implementation of LED controller with a stable constant-current, a low-power and low-heat function. From the simulation result, the power consumption of the proposed LED controller using adiabatic operation was reduced to about 87% in comparison with conventional operation with a constant VDD. The proposed circuit is expected to be an alternative LED controller which is sensitive to external conditions such as heat.

  2. Direct Current Smart Micro-grids for Distributed Generation with Renewable Sources

    Directory of Open Access Journals (Sweden)

    Renato RIZZO

    2013-06-01

    Full Text Available The wide diffusion of renewable energy sources encourage the distribution of electrical energy by the so called Distributed Generation, where large power plants are substituted by small-scale environmentally friendly technologies. Moreover micro-grids are considered which concept assumes a cluster of loads and micro-sources operating as a single controllable system that provides both power and heat to its local area. This influences the operation of distributed generation. This research paper deals with the distributed generation evolution, considering the technologies for generation from renewable sources, up to the smart micro-grids, i.e. in domestic applications where direct current micro-grids are considered and smart micro-grid concept is introduced.

  3. Current developments with TRIUMF’s titanium-sapphire laser based resonance ionization laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lassen, J., E-mail: LASSEN@triumf.ca; Li, R. [TRIUMF (Canada); Raeder, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany); Zhao, X.; Dekker, T. [TRIUMF (Canada); Heggen, H. [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany); Kunz, P.; Levy, C. D. P.; Mostanmand, M.; Teigelhöfer, A.; Ames, F. [TRIUMF (Canada)

    2017-11-15

    Developments at TRIUMF’s isotope separator and accelerator (ISAC) resonance ionization laser ion source (RILIS) in the past years have concentrated on increased reliability for on-line beam delivery of radioactive isotopes to experiments, as well as increasing the number of elements available through resonance ionization and searching for ionization schemes with improved efficiency. The current status of these developments is given with a list of two step laser ionization schemes implemented recently.

  4. Current developments with TRIUMF's titanium-sapphire laser based resonance ionization laser ion source. An overview

    Science.gov (United States)

    Lassen, J.; Li, R.; Raeder, S.; Zhao, X.; Dekker, T.; Heggen, H.; Kunz, P.; P. Levy, C. D.; Mostanmand, M.; Teigelhöfer, A.; Ames, F.

    2017-11-01

    Developments at TRIUMF's isotope separator and accelerator (ISAC) resonance ionization laser ion source (RILIS) in the past years have concentrated on increased reliability for on-line beam delivery of radioactive isotopes to experiments, as well as increasing the number of elements available through resonance ionization and searching for ionization schemes with improved efficiency. The current status of these developments is given with a list of two step laser ionization schemes implemented recently.

  5. Recent research activities and future subjects on stable- and radio-isotopes of chlorine in environment

    Energy Technology Data Exchange (ETDEWEB)

    Kushita, Kouhei [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report reviews the recent studies on the stable- and radio-isotopes of chlorine from a viewpoint of environmental science, partly including historic references on this element. First, general properties, occurrence, and utilization of chlorine are described. Secondly, current status and research works on chlorine-compounds, which attract special attention in recent years as environmentally hazardous materials, are reported. Thirdly, research works on stable chlorine isotopes, {sup 35}Cl and {sup 37}Cl, are described with a focus laid on the newly-developed techniques; isotopic ratio mass spectrometry (IRMS) and thermal ionization mass spectrometry (TIMS). Fourthly, recent research works on chlorine radioisotopes, {sup 36}Cl etc., are described, focusing on the development of accelerator mass spectrometry (AMS) and its application to geochemistry and others. Finally, taking account of the above-mentioned recent works on Cl isotopes, possible future research subjects are discussed. (author)

  6. Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources

    Science.gov (United States)

    Dong, Chenyin; Taylor, Mark Patrick

    2017-07-01

    Resolving the source of environmental contamination is the critical first step in remediation and exposure prevention. Australia's oldest silver-zinc-lead mine at Broken Hill (>130 years old) has generated a legacy of contamination and is associated with persistent elevated childhood blood lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum at Broken Hill include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 μg/m2/day) and its bioaccessibility (mean 75% of total Pb) is greatest adjacent to the active mining operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust particles were more angular, had higher sulfur content and had little or no iron and manganese. Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406) that are a close match (99%) to the ore body with values slightly lower (94%) at the edge of the city. The weight of evidence supports the conclusion that contemporary dust Pb contamination in Broken Hill is sourced primarily from current mining activities and not from weathering or legacy sources.

  7. Galvanically Decoupled Current Source Modules for Multi-Channel Bioimpedance Measurement Systems

    Directory of Open Access Journals (Sweden)

    Roman Kusche

    2017-10-01

    Full Text Available Bioimpedance measurements have become a useful technique in the past several years in biomedical engineering. Especially, multi-channel measurements facilitate new imaging and patient monitoring techniques. While most instrumentation research has focused on signal acquisition and signal processing, this work proposes the design of an excitation current source module that can be easily implemented in existing or upcoming bioimpedance measurement systems. It is galvanically isolated to enable simultaneous multi-channel bioimpedance measurements with a very low channel-coupling. The system is based on a microcontroller in combination with a voltage-controlled current source circuit. It generates selectable sinusoidal excitation signals between 0.12 and 1.5 mA in a frequency range from 12 to 250 kHz, whereas the voltage compliance range is ±3.2 V. The coupling factor between two current sources, experimentally galvanically connected with each other, is measured to be less than −48 dB over the entire intended frequency range. Finally, suggestions for developments in the future are made.

  8. Improved PHIP polarization using a precision, low noise, voltage controlled current source

    Science.gov (United States)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  9. Variable Conductance Heat Pipes for Radioisotope Stirling Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall program objective is to develop a high temperature variable conductance heat pipe (VCHP) backup radiator, and integrate it into a Stirling radioisotope...

  10. Advanced Radiative Emitters for Radioisotope Thermophotovoltaic Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radioisotope Power Systems (RPS) are critical for future flagship exploration missions in space and on planetary surfaces. Small improvements in the RPS performance,...

  11. Advanced Radiative Emitters for Radioisotope Thermophotovoltaic Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radioisotope Power Systems (RPS) are critical for future space and planetary exploration missions. Small improvements in the RPS performance, weight, size, and/or...

  12. Work in progress: radioisotopic evaluation of gastroplasty patients

    Energy Technology Data Exchange (ETDEWEB)

    Drane, W.E.; Marks, D.S.; Simms, S.M.; Saylor, J.G.; Haas, P.A.; Kambouris, A.A.

    1983-04-01

    Radioisotopic gastric emptying studies, using technetium-99m-sulfur-colloid-labeled egg, were performed in 14 patients who had undergone gastroplasty. The radioisotopic method was found to be a good quantitative indicator of the amount of solids that empty from the stomach and a useful tool in the longterm follow-up of gastroplasty patients. It was particularly helpful in evaluating the efficacy of surgery in patients with poor postsurgical weight reduction.

  13. Work in progress: radioisotopic evaluaton of gastroplasty patients

    Energy Technology Data Exchange (ETDEWEB)

    Drane, W.E.; Marks, D.S.; Simms, S.M.; Saylor, J.G.; Haas, P.A.; Kambouris, A.H.

    1983-04-01

    Radioisotopic gastric emptying studies, using technetium-99m-sulfur-colloid-labeled egg, were performed in 14 patients who had undergone gastroplasty. The radioisotopic method was found to be a good quantitative indicator of the amount of solids that empty from the stomach and a useful tool in the long-term follow-up of gastroplasty patients. It was particularly helpful in evaluating the efficacy of surgery in patients with poor postsurgical weight reduction.

  14. Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

    OpenAIRE

    Qureshi, Tabassum-Ur-Razaq; Chatwin, Chris; Huber, Nicolas; Zarafshani, Ali; Tunstall, Benjamin; Wang, Wei

    2010-01-01

    The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifier...

  15. Design and simulation of a nanoelectronic DG MOSFET current source using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Djeffal, F. [LEA, Department of Electronics, University of Batna 05000 (Algeria)], E-mail: faycaldzdz@hotmail.com; Dibi, Z. [LEA, Department of Electronics, University of Batna 05000 (Algeria)], E-mail: zohirdibi@univ-batna.dz; Hafiane, M.L.; Arar, D. [LEA, Department of Electronics, University of Batna 05000 (Algeria)

    2007-09-15

    The double gate (DG) MOSFET has received great attention in recent years owing to the inherent suppression of short channel effects (SCEs), excellent subthreshold slope (S), improved drive current (I{sub ds}) and transconductance (gm), volume inversion for symmetric devices and excellent scalability. Therefore, simulation tools which can be applied to design nanoscale transistors in the future require new theory and modeling techniques that capture the physics of quantum transport accurately and efficiently. In this sense, this work presents the applicability of the artificial neural networks (ANN) for the design and simulation of a nanoelectronic DG MOSFET current source. The latter is based on the 2D numerical Non-Equilibrium Green's Function (NEGF) simulation of the current-voltage characteristics of an undoped symmetric DG MOSFET. Our results are discussed in order to obtain some new and useful information about the ULSI technology.

  16. Sourceless formation evaluation. An LWD solution providing density and neutron measurements without the use of radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, R.; Reichel, N. [Schlumberger, Sungai Buloh (Malaysia)

    2013-08-01

    For many years the industry has been searching for a way to eliminate the logistical difficulties and risk associated with deployment of radioisotopes for formation evaluation. The traditional gamma-gamma density (GGD) measurement uses the scattering of 662-keV gamma rays from a 137Cs radioisotopic source, with a 30.17-year half-life, to determine formation density. The traditional neutron measurement uses an Am-Be source emitting neutrons with an energy around 4 MeV, with a half-life of 432 years. Both these radioisotopic sources pose health, security, and environmental risks. Pulsed-neutron generators have been used in the industry for several decades in wireline tools and more recently in logging-while-drilling tools. These generators produce 14-MeV neutrons, many of which interact with the nuclei in the formation. Elastic collisions allow a neutron porosity measurement to be derived, which has been available to the industry since 2005. Inelastic interactions are typically followed by the emission of a variety of high-energy gamma rays. Similar to the case of the GGD measurement, the transport and attenuation of these gamma rays is a strong function of the formation density. However, the gamma-ray source is now distributed over a volume within the formation, where gamma rays have been induced by neutron interactions and the source can no longer be considered to be a point as in the case of a radioisotopic source. In addition, the extent of the induced source region depends on the transport of the fast neutrons from the source to the point of gamma-ray production. Even though the physics is more complex, it is possible to measure the formation density if the fast neutron transport is taken into account when deriving the density answer. This paper briefly reviews the physics underlying the sourceless neutron porosity and recently introduced neutron-gamma density (SNGD) measurement, demonstrates how they can be used in traditional workflows and illustrates their

  17. The monoclonal antibodies as radioisotope vectors; Les anticorps monoclonaux vecteurs de radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Barbet, J. [IMMUNOTECH, 13 - Marseille (France)

    1994-07-01

    The radioisotope targetting wants to show that only a reflection integrating the whole parameters which can interfere after the vector molecule injection, may give real success chances in the conception and the implementation of the targetting technologies. About 20 years later, the discovery of monoclonal antibodies, the balance, estimated on the product number placed at disposal of the clinicians remains very poor. Nevertheless it is undeniable that the immunoscintigraphy, the immunoradio-controlled surgery and radioimmunotherapy proved their clinical efficiency on experimental level. 6 refs., 3 tabs., 3 figs.

  18. Accidental radioisotope burns - Management of late sequelae

    Directory of Open Access Journals (Sweden)

    Varghese Bipin

    2010-10-01

    Full Text Available Accidental radioisotope burns are rare. The major components of radiation injury are burns, interstitial pneumonitis, acute bone marrow suppression, acute renal failure and adult respiratory distress syndrome. Radiation burns, though localized in distribution, have systemic effects, and can be extremely difficult to heal, even after multiple surgeries. In a 25 year old male who sustained such trauma by accidental industrial exposure to Iridium192 the early presentation involved recurrent haematemesis, pancytopenia and bone marrow suppression. After three weeks he developed burns in contact areas in the left hand, left side of the chest, abdomen and right inguinal region. All except the inguinal wound healed spontaneously but the former became a non-healing ulcer. Pancytopenia and bone marrow depression followed. He was treated with morphine and NSAIDs, epidural buprinorphine and bupivicaine for pain relief, steroids, antibiotics followed by wound excision and reconstruction with tensor fascia lata(TFL flap. Patient had breakdown of abdominal scar later and it was excised with 0.5 cm margins up to the underlying muscle and the wound was covered by a latissimis dorsi flap. Further scar break down and recurrent ulcers occurred at different sites including left wrist, left thumb and right heel in the next two years which needed multiple surgical interventions.

  19. Toward high performance radioisotope thermophotovoltaic systems using spectral control

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiawa, E-mail: xiawaw@mit.edu [Electrical Engineering Department, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Chan, Walker [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Stelmakh, Veronika [Electrical Engineering Department, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Celanovic, Ivan [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Fisher, Peter [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA02139 (United States); Physics Department, Massachusetts Institute of Technology, Cambridge, MA02139 (United States)

    2016-12-01

    This work describes RTPV-PhC-1, an initial prototype for a radioisotope thermophotovoltaic (RTPV) system using a two-dimensional photonic crystal emitter and low bandgap thermophotovoltaic (TPV) cell to realize spectral control. We validated a system simulation using the measurements of RTPV-PhC-1 and its comparison setup RTPV-FlatTa-1 with the same configuration except a polished tantalum emitter. The emitter of RTPV-PhC-1 powered by an electric heater providing energy equivalent to one plutonia fuel pellet reached 950 °C with 52 W of thermal input power and produced 208 mW output power from 1 cm{sup 2} TPV cell. We compared the system performance using a photonic crystal emitter to a polished flat tantalum emitter and found that spectral control with the photonic crystal was four times more efficient. Based on the simulation, with more cell areas, better TPV cells, and improved insulation design, the system powered by a fuel pellet equivalent heat source is expected to reach an efficiency of 7.8%.

  20. Modelling and simulation of current fed dc to dc converter for PHEV applications using renewable source

    Science.gov (United States)

    Milind Metha, Manish; Tutki, Sanjay; Rajan, Aju; Elangovan, D.; Arunkumar, G.

    2017-11-01

    With the current rate of depletion of the fossil fuel the need to switch on to the renewable energy sources is the need of the hour. Thus the need for new and efficient converters arises so as to replace the existing less efficient diesel and petroleum IC engines with renewable energy sources. The PHEVs, which have been launched in the market, and Upcoming PHEVs have converters around 380V to 400V generated with a power range between 2KW to 2.8KW. The fundamental target of this paper is to plan a productive converter keeping in mind cost and size restriction. In this paper, a two-stage dc-dc converter is proposed. The proposed converter is utilized to venture up a voltage from 24V (photovoltaic source) to a yield voltage of 400V to take care of a power demand of 2.4kW for a plug-in hybrid electric vehicle (PHEV) application considering the real time scenario of PHEV. This paper talks about in detail why the current fed converter is utilized alongside a voltage doubler thus minimizing the transformer turns thereby reducing the overall size of the final product. Simulation results along with calculation for the duty cycle of the firing sequence for different value of transformer turns are presented for a prototype unit.

  1. Inverse current source density method in two dimensions: inferring neural activation from multielectrode recordings.

    Science.gov (United States)

    Łęski, Szymon; Pettersen, Klas H; Tunstall, Beth; Einevoll, Gaute T; Gigg, John; Wójcik, Daniel K

    2011-12-01

    The recent development of large multielectrode recording arrays has made it affordable for an increasing number of laboratories to record from multiple brain regions simultaneously. The development of analytical tools for array data, however, lags behind these technological advances in hardware. In this paper, we present a method based on forward modeling for estimating current source density from electrophysiological signals recorded on a two-dimensional grid using multi-electrode rectangular arrays. This new method, which we call two-dimensional inverse Current Source Density (iCSD 2D), is based upon and extends our previous one- and three-dimensional techniques. We test several variants of our method, both on surrogate data generated from a collection of Gaussian sources, and on model data from a population of layer 5 neocortical pyramidal neurons. We also apply the method to experimental data from the rat subiculum. The main advantages of the proposed method are the explicit specification of its assumptions, the possibility to include system-specific information as it becomes available, the ability to estimate CSD at the grid boundaries, and lower reconstruction errors when compared to the traditional approach. These features make iCSD 2D a substantial improvement over the approaches used so far and a powerful new tool for the analysis of multielectrode array data. We also provide a free GUI-based MATLAB toolbox to analyze and visualize our test data as well as user datasets.

  2. Variable speed wind turbine generator system with current controlled voltage source inverter

    Energy Technology Data Exchange (ETDEWEB)

    Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)

    2011-07-15

    highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  3. Peculiarities of constructing planar microminiature current sources based on secondary emission cathode excited by an edge FEA

    Science.gov (United States)

    Zakharchenko, Yu. F.; Sinitsyn, N. I.; Gulyaev, Yu. V.; Saveliev, S. G.

    2003-06-01

    The current characteristics of a microminiature current source are theoretically studied. It is based on a secondary emission cathode excited by the current from a field emission array (FEA). This principle of constructing current sources allows the current from the FEA to be amplified by 10 times or more by using film materials which show high secondary emission coefficient, for example, MgO, Al 2O 3, and BeO. These features yield an opportunity for a substantially longer durability for a film FEA and the source as a whole.

  4. Revealing sources and chemical identity of iron ligands across the California Current System

    Science.gov (United States)

    Boiteau, R.; Repeta, D.; Fitzsimmons, J. N.; Parker, C.; Twining, B. S.; Baines, S.

    2016-02-01

    The California Current System is one of the most productive regions of the ocean, fueled by the upwelling of nutrient rich water. Differences in the supply of micronutrient iron to surface waters along the coast lead to a mosaic of iron-replete and iron-limited conditions across the region, affecting primary production and community composition. Most of the iron in this region is supplied by upwelling of iron from the benthic boundary layer that is complexed by strong organic ligands. However, the source, identity, and bioavailability of these ligands are unknown. Here, we used novel hyphenated chromatography mass spectrometry approaches to structurally characterize organic ligands across the region. With these methods, iron ligands are detected with liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC-ICPMS), and then their mass and fragmentation spectra are determined by high resolution electrospray ionization mass spectrometry (LC-ESIMS). Iron isotopic exchange was used to compare the relative binding strengths of different ligands. Our survey revealed a broad range of ligands from multiple sources. Benthic boundary layers and anoxic sediments were sources of structurally amorphous weak ligands, likely organic degradation products, as well as siderophores, strong iron binding molecules that facilitate iron acquisition. In the euphotic zone, marine microbes and zooplankton grazing produced a wide distribution of other compounds that included known and novel siderophores. This work demonstrates that the chemical nature of ligands from different sources varies substantially and has important implications for iron biogeochemical cycling and availability to members of the microbial community.

  5. LORETA current source density for duration mismatch negativity and neuropsychological assessment in early schizophrenia.

    Directory of Open Access Journals (Sweden)

    Tomohiro Miyanishi

    Full Text Available INTRODUCTION: Patients with schizophrenia elicit cognitive decline from the early phase of the illness. Mismatch negativity (MMN has been shown to be associated with cognitive function. We investigated the current source density of duration mismatch negativity (dMMN, by using low-resolution brain electromagnetic tomography (LORETA, and neuropsychological performance in subjects with early schizophrenia. METHODS: Data were obtained from 20 patients meeting DSM-IV criteria for schizophrenia or schizophreniform disorder, and 20 healthy control (HC subjects. An auditory odd-ball paradigm was used to measure dMMN. Neuropsychological performance was evaluated by the brief assessment of cognition in schizophrenia Japanese version (BACS-J. RESULTS: Patients showed smaller dMMN amplitudes than those in the HC subjects. LORETA current density for dMMN was significantly lower in patients compared to HC subjects, especially in the temporal lobes. dMMN current density in the frontal lobe was positively correlated with working memory performance in patients. CONCLUSIONS: This is the first study to identify brain regions showing smaller dMMN current density in early schizophrenia. Further, poor working memory was associated with decreased dMMN current density in patients. These results are likely to help understand the neural basis for cognitive impairment of schizophrenia.

  6. X-ray framing camera for pulsed, high current, electron beam x-ray sources

    CERN Document Server

    Failor, B H; Riordan, j c; Lojewski, D Y

    2007-01-01

    High power x-ray sources built for nuclear weapons effects testing are evolving toward larger overall diameters and smaller anode cathode gaps. We describe a framing camera developed to measure the time-evolution of these 20-50 ns pulsed x-ray sources produced by currents in the 1.5-2.5 MA range and endpoint voltages between 0.2 and 1.5 MV. The camera has up to 4 frames with 5 ns gate widths; the frames are separated by 5 ns. The image data are recorded electronically with a gated intensified CCD camera and the data are available immediately following a shot. A fast plastic scintillator (2.1 ns decay time) converts the x-rays to visible light and, for high sensitivity, a fiber optic imaging bundle carries the light to the CCD input. Examples of image data are shown.

  7. Development of a high-current hydrogen-negative ion source for LHD-NBI system

    Energy Technology Data Exchange (ETDEWEB)

    Takeiri, Yasuhiko; Osakabe, Masaki; Tsumori, Katsuyoshi; Oka, Yoshihide; Kaneko, Osamu; Asano, Eiji; Kawamoto, Toshikazu; Akiyama, Ryuichi [National Inst. for Fusion Science, Toki, Gifu (Japan); Tanaka, Masanobu

    1998-08-01

    We have developed a high-current hydrogen-negative ion source for a negative-ion-based NBI system in Large Helical Device (LHD). The ion source is a cesium-seeded volume-production source equipped with an external magnetic filter. An arc chamber is rectangular, the dimensions of which are 35 cm x 145 cm in cross section and 21 cm in depth. A three-grid single-stage accelerator is divided into five sections longitudinally, each of which has 154(14 x 11) apertures in an area of 25 cm x 25 cm. The ion source was tested in the negative-NBI teststand, and 25 A of the negative ion beam is incident on a beamdump 13 m downstream with an energy of 104 keV for 1 sec. Multibeamlets of 770 are focused on a focal point 13 m downstream with an averaged divergence angle of 10 mrad by the geometrical arrangement of five sections of grid and the aperture displacement technique of the grounded grid. A uniform beam in the vertical direction over 125 cm is obtained with uniform plasma production in the arc chamber by balancing individual arc currents flowing through each filament. Long-pulse beam production was performed, and 1.3 MW of the negative ion beam is incident on the beamdump for 10 sec, and the temperature rise of the cooling water is almost saturated for the extraction and the grounded grids. These results satisfy the first-step specification of the LHD-NBI system. (author)

  8. Neptune Orbiters Utilizing Solar and Radioisotope Electric Propulsion

    Science.gov (United States)

    Fiehler, Douglas I.; Oleson, Steven R.

    2004-01-01

    In certain cases, Radioisotope Electric Propulsion (REP), used in conjunction with other propulsion systems, could be used to reduce the trip times for outer planetary orbiter spacecraft. It also has the potential to improve the maneuverability and power capabilities of the spacecraft when the target body is reached as compared with non-electric propulsion spacecraft. Current missions under study baseline aerocapture systems to capture into a science orbit after a Solar Electric Propulsion (SEP) stage is jettisoned. Other options under study would use all REP transfers with small payloads. Compared to the SEP stage/Aerocapture scenario, adding REP to the science spacecraft as well as a chemical capture system can replace the aerocapture system but with a trip time penalty. Eliminating both the SEP stage and the aerocapture system and utilizing a slightly larger launch vehicle, Star 48 upper stage, and a combined REP/Chemical capture system, the trip time can nearly be matched while providing over a kilowatt of science power reused from the REP maneuver. A Neptune Orbiter mission is examined utilizing single propulsion systems and combinations of SEP, REP, and chemical systems to compare concepts.

  9. A Methodology for Implementing the Department of Defense’s Current In-Sourcing Policy

    Science.gov (United States)

    2011-01-01

    from www.rand.org as a public service of the RAND Corporation. CHILDREN AND FAMILIES EDUCATION AND THE ARTS ENERGY AND ENVIRONMENT HEALTH AND HEALTH... DHA ) Fact Sheet,” web page, undated). 12 A Methodology for Implementing the Department of Defense’s Current In-Sourcing Policy noted, “can be...Guidelines, Washington, D.C., GAO-10-58R, 2009. U.S. Office of Personnel Management, “Direct-Hire Authority ( DHA ) Fact Sheet,” web page, undated. As of

  10. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Directory of Open Access Journals (Sweden)

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  11. Reduction of Beam Current Noise in the FNAL Magnetron Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Bollinger, D. S. [Fermilab; Karns, P. R. [Fermilab; Tan, C. Y.

    2014-01-01

    The new FNAL Injector Line with a circular dimple magnetron ion source has been operational since December of 2013. Since the new injector came on line there have been variations in the H- beam current flattop observed near the downstream end of the linac. Several different cathode geometries including a hollow cathode suggested by Dudnikov [1] were tried. We expanded on those studies by trying mixtures ranging from 0.25%N, 99.75%H to 3%N, 97%H. The results of these studies in our test stand will be presented in this paper.

  12. Chemistry of Cosmogenic Radioisotopes in the Stratosphere

    Science.gov (United States)

    Rowland, F. S.

    2003-12-01

    Bombardment of Earth's atmosphere by Gev cosmic ray protons produces two neutrons/cm2/second, which react with 14N nuclei to form 14C. The initial stratospheric reaction of the bare 14C atom with O2 forms 14CO, which is subsequently oxidized to 14CO2 by HO. The 14CO2 is then the basis for age-dating studies of inorganic carbon, and of organic carbon after incorporation by photosynthesis. Proton spallation of light nuclei (chiefly 14N, 16O) produces various isotopic fragments, many of them radioactive, containing 8 or fewer protons and 10 or fewer neutrons. For geophysical studies, the most important of the radioisotopes so produced are 3H, 7Be, and 10Be. Proton spallation of 40Ar produces many isotopes with atomic weight less than 40, including 34Cl, 36Cl, 38Cl, 39Cl, 35S, 38S, 22Na, 24Na, 32Si, 32P, and 33P, all of which have been detected in the atmosphere. The "million year" isotopes (10Be, 36Cl) are useful for geological dating. The short-lived isotopes were collected both from rainwater captured at ground level, and on filter paper at 18 kilometers altitude carried by an RB-57 aircraft (1970, J. A. Young, C. W. Thomas, N. A. Wogman and R. W. Perkins, JGR, 75, 2385). The radioisotopes were measured with multidimensional gamma ray spectroscopy, which was able to detect 24Na and 38Cl without prior chemical separation. Count rates as low as 0.1 count/minute were monitored, even in the presence of 107 counts/minute of fallout fission products from nuclear testing in the atmosphere. This fallout background is now greatly reduced because of the four decades old ban on nuclear testing in the atmosphere. The stratospheric collection of 24Na (15 hour half-life) was interpreted as scavenging of the radiosodium by particulate matter, and retention on filter paper with an efficiency of 100 percent within the statistical accuracy in comparison with its production in argon tanks carried on the aircraft. The efficiency of collection of radiochlorine atoms was only about 1

  13. Asymmetrical Fault Correction for the Sensitive Loads Using a Current Regulated Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Syed Sabir Hussain Bukhari

    2016-03-01

    Full Text Available Numerous industrial applications involve loads that are very sensitive to electrical supply instabilities. These instances involve various types of voltage imbalances as well as more serious disturbances such as symmetrical and asymmetrical faults. This paper proposes a cost-effective voltage imbalance and asymmetrical fault correction solution for the three phase sensitive loads utilizing an industry-standard current regulated voltage source inverter by connecting it in parallel to the grid mains powering to the sensitive load. The inverter regulates the current for the load and never permits it to go beyond a prescribed value under any type of asymmetrical fault condition, which ensures high power regulating and conditioning capacities. Experimental results are obtained from a small laboratory size prototype to validate the operation of the proposed technique.

  14. Modeling and simulation of multilevel current source inverter based on SIMetrix/SIMPLIS

    Science.gov (United States)

    Bao, Jianyu; Bao, Weibing; Fang, Weizhong; Ma, Xiushui

    2011-05-01

    Based on analysis of operational principle of single-phase multilevel current source inverter (MCSI), a novel method for modeling and simulation of MCSI system was proposed. In SIMetrix/SIMPLIS, the simulation model of a kind of singlephase 5-level CSI was developed by using hierarchy design. In the control system, the multi-carrier PWM modulation strategy was adopted, the current balance control for intermediate DC-link inductor was implemented on the principle of redundant switching combinations. The reasonability and validity were testified by the coincidence of the simulation results and theoretical analysis. This novel method is also suitable for modeling other power electronics inverters and offers a new thinking for designing actual power electronic circuits.

  15. Radioisotopes present in building materials of workplaces

    Science.gov (United States)

    Del Claro, F.; Paschuk, S. A.; Corrêa, J. N.; Denyak, V.; Kappke, J.; Perna, A. F. N.; Martins, M. R.; Santos, T. O.; Rocha, Z.; Schelin, H. R.

    2017-11-01

    The isotope 222Rn is responsible for approximately half of the effective annual dose received by the world population. The decay products of 222Rn interacting with the cells of biological tissue of lungs have very high probability to induce cancer. The present survey was focused in the evaluation of activity concentration of 222Rn and other radioisotopes related to the building materials at workplaces at Curitiba - Paraná State. For this purpose, the instant radon detector AlphaGUARD (Saphymo GmbH) was used to measure the average concentrations of 222Rn in building materials, which were also submitted to gamma spectrometry analysis for qualitative and quantitative evaluation of the radionuclides present in samples of sand, mortar, blue crushed stone (Gneissic rock), red crushed stone (Granite), concrete and red bricks. The main radionuclides evaluated by gamma spectrometry in building material samples were 238U/226Ra, 232Th and 40K. These measurements were performed at the Laboratory of Applied Nuclear Physics of the Federal University of Technology - Paraná in collaboration with the Center of Nuclear Technology Development (CDTN - CNEN). The results of the survey present the concentration values of 222Rn related to construction materials in a range from 427±40.52 Bq/m³ to 2053±90.06 Bq/m³. The results of gamma spectroscopy analysis show that specific activity values for the mentioned isotopes are similar to the results indicated by the literature. Nevertheless, the present survey is showing the need of further studies and indicates that building materials can contribute significantly to indoor concentration of 222Rn.

  16. Simulation-Based Validation for Four-Dimensional Multi-Channel Ultrasound Current Source Density Imaging

    Science.gov (United States)

    Wang, Zhaohui; Witte, Russell S.

    2015-01-01

    Ultrasound current source density imaging (UCSDI), which has application to the heart and brain, exploits the acoustoelectric (AE) effect and Ohm's law to detect and map an electrical current distribution. In this study, we describe 4-D UCSDI simulations of a dipole field for comparison and validation with bench-top experiments. The simulations consider the properties of the ultrasound pulse as it passes through a conductive medium, the electric field of the injected dipole, and the lead field of the detectors. In the simulation, the lead fields of detectors and electric field of the dipole were calculated by the finite element (FE) method, and the convolution and correlation in the computation of the detected AE voltage signal were accelerated using 3-D fast Fourier transforms. In the bench-top experiment, an electric dipole was produced in a bath of 0.9% NaCl solution containing two electrodes, which injected an ac pulse (200 Hz, 3 cycles) ranging from 0 to 140 mA. Stimulating and recording electrodes were placed in a custom electrode chamber made on a rapid prototype printer. Each electrode could be positioned anywhere on an x-y grid (5 mm spacing) and individually adjusted in the depth direction for precise control of the geometry of the current sources and detecting electrodes. A 1-MHz ultrasound beam was pulsed and focused through a plastic film to modulate the current distribution inside the saline-filled tank. AE signals were simultaneously detected at a sampling frequency of 15 MHz on multiple recording electrodes. A single recording electrode is sufficient to form volume images of the current flow and electric potentials. The AE potential is sensitive to the distance from the dipole, but is less sensitive to the angle between the detector and the dipole. Multi-channel UCSDI potentially improves 4-D mapping of bioelectric sources in the body at high spatial resolution, which is especially important for diagnosing and guiding treatment of cardiac and

  17. Development of a high average current polarized electron source with long cathode operational lifetime

    Directory of Open Access Journals (Sweden)

    C. K. Sinclair

    2007-02-01

    Full Text Available Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2×10^{5}   C/cm^{2} and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  18. Simulation of a distributed current source in a linear format CFA

    Science.gov (United States)

    Pearlman, Marcus; Browning, Jim

    2015-11-01

    A fundamental limit on Crossed-Field Amplifiers (CFA) gain is beam to RF power ratio. With too much beam power, the RF signal on the slow wave circuit is ``swamped.'' It is proposed here that a controllable, distributed cathode source can be used to tailor current injection and optimize gain. In this work a linear format CFA with a meander line slow wave circuit is tested experimentally and numerically using Vsim. Simulations of the original design, which operates at 900 MHz, shows 100 mA. This beam current is higher than the capabilities of the Field Emitter Array cathodes available to the group; therefore no experimental gain was observed. To be able to compare simulation to experiment, the CFA model under study was changed to the experiment used at Northeastern University in 1991, which also uses a meander line circuit and an injected beam configuration. Direct comparisons between the simulation and this experiment are performed to validate the model. Additional simulations study the effect of different current distributions on gain, bandwidth, and efficiency. Practical considerations such as how to control the energy of the beam separately from the sole potential in order to minimize lost current to sole are also examined. This research was supported by the Air Force Office of Scientific Research and the department of Electrical and Computer Engineering at Boise State University.

  19. Comparative analysis of 11 different radioisotopes for palliative treatment of bone metastases by computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Guerra Liberal, Francisco D. C., E-mail: meb12020@fe.up.pt, E-mail: adriana-tavares@msn.com; Tavares, Adriana Alexandre S., E-mail: meb12020@fe.up.pt, E-mail: adriana-tavares@msn.com; Tavares, João Manuel R. S., E-mail: tavares@fe.up.pt [Instituto de Engenharia Mecânica e Gestão Industrial, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, Porto 4200-465 (Portugal)

    2014-11-01

    Purpose: Throughout the years, the palliative treatment of bone metastases using bone seeking radiotracers has been part of the therapeutic resources used in oncology, but the choice of which bone seeking agent to use is not consensual across sites and limited data are available comparing the characteristics of each radioisotope. Computational simulation is a simple and practical method to study and to compare a variety of radioisotopes for different medical applications, including the palliative treatment of bone metastases. This study aims to evaluate and compare 11 different radioisotopes currently in use or under research for the palliative treatment of bone metastases using computational methods. Methods: Computational models were used to estimate the percentage of deoxyribonucleic acid (DNA) damage (fast Monte Carlo damage algorithm), the probability of correct DNA repair (Monte Carlo excision repair algorithm), and the radiation-induced cellular effects (virtual cell radiobiology algorithm) post-irradiation with selected particles emitted by phosphorus-32 ({sup 32}P), strontium-89 ({sup 89}Sr), yttrium-90 ({sup 90}Y ), tin-117 ({sup 117m}Sn), samarium-153 ({sup 153}Sm), holmium-166 ({sup 166}Ho), thulium-170 ({sup 170}Tm), lutetium-177 ({sup 177}Lu), rhenium-186 ({sup 186}Re), rhenium-188 ({sup 188}Re), and radium-223 ({sup 223}Ra). Results: {sup 223}Ra alpha particles, {sup 177}Lu beta minus particles, and {sup 170}Tm beta minus particles induced the highest cell death of all investigated particles and radioisotopes. The cell survival fraction measured post-irradiation with beta minus particles emitted by {sup 89}Sr and {sup 153}Sm, two of the most frequently used radionuclides in the palliative treatment of bone metastases in clinical routine practice, was higher than {sup 177}Lu beta minus particles and {sup 223}Ra alpha particles. Conclusions: {sup 223}Ra and {sup 177}Lu hold the highest potential for palliative treatment of bone metastases of all

  20. Municipal solid waste (MSW) as a renewable source of energy: current and future practices in China.

    Science.gov (United States)

    Cheng, Hefa; Hu, Yuanan

    2010-06-01

    With rapid economic growth and massive urbanization, China faces the problem of municipal solid waste (MSW) disposal and the pressing need for development of alternative energy. Waste-to-energy (WTE) incineration, which recovers energy from discarded MSW and produces electricity and/or steam for heating, is recognized as a renewable source of energy and is playing an increasingly important role in MSW management in China. This article provides an overview of the WTE industry, discusses the major challenges in expanding WTE incineration in China, namely, high capital and operational costs, equipment corrosion, air pollutant emissions, and fly ash disposal. A perspective on MSW as a renewable energy source in China is also presented. Currently, only approximately 13% of MSW generated in China is disposed in WTE facilities. With the significant benefits of environmental quality, the reduction of greenhouse gas (GHG) emissions, and government policies and financial incentives as a renewable energy source, WTE incineration industry is expected to experience significant growth in the coming decade and make greater contribution to supplying renewable energy in China. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Design and implementation of current fed DC-DC converter for PHEV application using renewable source

    Science.gov (United States)

    Milind Metha, Manish; Tutki, Sanjay; Rajan, Aju; Elangovan, D.; Arunkumar, G.

    2017-11-01

    As the fossil fuels are depleting day by day, the use of renewable energy sources came into existence and they evolved a lot lately. To increase efficiency and productivity in the hybrid vehicles, the existence less efficient petroleum and diesel IC engines need to be replaced with the new and efficient converters with renewable energy sources. This has to be done in such a way that impacts three factors mainly: cost, efficiency and reliability. The PHEVs that have been launched and the upcoming PHEVs using converters with voltage range around 380V to 400V generated with power ranges between 2.4KW to 2.8KW. The basic motto of this paper is to design a prolific converter while considering the factor such as cost and size. In this paper, a two stage DC-DC converter is proposed and the proposed DC-DC converter is utilized to endeavour voltage from 24V (photovoltaic source) to a yield voltage of 400V and to meet the power demand of 250W, since only one panel is being used for this proposed paper. This paper discuss in detail about why and how the current fed DC-DC converter is utilized along with a voltage doubler, thus reducing transformer turns and thereby reducing overall size of the product. Simulation and hardware results have been presented along with calculations for duty cycle required for firing sequence for different values of transformer turns.

  2. Drift velocity of charged particles in magnetic fields and its relation to the direction of the source current

    Science.gov (United States)

    Essén, Hanno; Nordmark, Arne B.

    2016-10-01

    Integrable motion of charged particles in magnetic fields produced by stationary current distributions is investigated. We treat motion in the magnetic field from an infinite flat current sheet, a Harris current sheath, an infinite rectilinear current, and a dipole in its equatorial plane. We find that positively charged particles as a rule will drift in the same direction as the current that is the source of the magnetic field in question. The conclusion is that charged particles moving under the influence of current distributions tend to enhance the current and that this indicates current self-amplification.

  3. High Efficiency Thermoelectric Radioisotope Power Systems

    Science.gov (United States)

    El-Genk, Mohamed; Saber, Hamed; Caillat, Thierry

    2004-01-01

    The work performed and whose results presented in this report is a joint effort between the University of New Mexico s Institute for Space and Nuclear Power Studies (ISNPS) and the Jet Propulsion Laboratory (JPL), California Institute of Technology. In addition to the development, design, and fabrication of skutterudites and skutterudites-based segmented unicouples this effort included conducting performance tests of these unicouples for hundreds of hours to verify theoretical predictions of the conversion efficiency. The performance predictions of these unicouples are obtained using 1-D and 3-D models developed for that purpose and for estimating the actual performance and side heat losses in the tests conducted at ISNPS. In addition to the performance tests, the development of the 1-D and 3-D models and the development of Advanced Radioisotope Power systems for Beginning-Of-Life (BOM) power of 108 We are carried out at ISNPS. The materials synthesis and fabrication of the unicouples are carried out at JPL. The research conducted at ISNPS is documented in chapters 2-5 and that conducted at JP, in documented in chapter 5. An important consideration in the design and optimization of segmented thermoelectric unicouples (STUs) is determining the relative lengths, cross-section areas, and the interfacial temperatures of the segments of the different materials in the n- and p-legs. These variables are determined using a genetic algorithm (GA) in conjunction with one-dimensional analytical model of STUs that is developed in chapter 2. Results indicated that when optimized for maximum conversion efficiency, the interfacial temperatures between various segments in a STU are close to those at the intersections of the Figure-Of-Merit (FOM), ZT, curves of the thermoelectric materials of the adjacent segments. When optimizing the STUs for maximum electrical power density, however, the interfacial temperatures are different from those at the intersections of the ZT curves, but

  4. Laminar distribution of phase-amplitude coupling of spontaneous current sources and sinks

    Directory of Open Access Journals (Sweden)

    Roberto C Sotero

    2015-12-01

    Full Text Available Although resting-state functional connectivity is a commonly used neuroimaging paradigm, the underlying mechanisms remain unknown. Thalamo-cortical and cortico-cortical circuits generate oscillations at different frequencies during spontaneous activity. However, it remains unclear how the various rhythms interact and whether their interactions are lamina-specific. Here we investigated intra- and inter-laminar spontaneous phase-amplitude coupling (PAC. We recorded local-field potentials using laminar probes inserted in the forelimb representation of rat area S1. We then computed time-series of frequency-band- and lamina-specific current source density (CSD, and PACs of CSD for all possible pairs of the classical frequency bands in the range of 1–150 Hz. We observed both intra- and inter-laminar spontaneous PAC. Of 18 possible combinations, 12 showed PAC, with the highest measures of interaction obtained for the pairs of the theta/gamma and delta/gamma bands. Intra- and inter-laminar PACs involving layers 2/3–5a were higher than those involving layer 6. Current sinks (sources in the delta band were associated with increased (decreased amplitudes of high-frequency signals in the beta to fast gamma bands throughout layers 2/3–6. Spontaneous sinks (sources of the theta and alpha bands in layers 2/3 to 4 were on average linked to dipoles completed by sources (sinks in layer 6, associated with high (low amplitudes of the beta to fast-gamma bands in the entire cortical column. Our findings show that during spontaneous activity, delta, theta, and alpha oscillations are associated with periodic excitability, which for the theta and alpha bands is lamina--dependent. They further emphasize the differences between the function of layer 6 and that of the superficial layers, and the role of layer 6 in controlling activity in those layers. Our study links theories on the involvement of PAC in resting-state functional connectivity with previous work that

  5. Hair radioactivity as a measure of exposure to radioisotopes

    Science.gov (United States)

    Strain, W. H.; Pories, W. J.; Fratianne, R. B.; Flynn, A.

    1972-01-01

    Since many radioisotopes accumulate in hair, this tropism was investigated by comparing the radioactivity of shaved with plucked hair collected from rats at various time intervals up to 24 hrs after intravenous injection of the ecologically important radioisotopes, iodine-131, manganese-54, strontium-85, and zinc-65. The plucked hair includes the hair follicles where biochemical transformations are taking place. The data indicate a slight surge of each radioisotpe into the hair immediately after injection, a variation of content of each radionuclide in the hair, and a greater accumulation of radioactivity in plucked than in shaved hair. These results have application not only to hair as a measure of exposure to radioisotopes, but also to tissue damage and repair at the hair follicle.

  6. Towards an ankle neuroprosthesis for hybrid robotics: Concepts and current sources for functional electrical stimulation.

    Science.gov (United States)

    Casco, S; Fuster, I; Galeano, R; Moreno, J C; Pons, J L; Brunetti, F

    2017-07-01

    Hybrid rehabilitation robotics combine neuro-prosthetic devices (close-loop functional electrical stimulation systems) and traditional robotic structures and actuators to explore better therapies and promote a more efficient motor function recovery or compensation. Although hybrid robotics and ankle neuroprostheses (NPs) have been widely developed over the last years, there are just few studies on the use of NPs to electrically control both ankle flexion and extension to promote ankle recovery and improved gait patterns in paretic limbs. The aim of this work is to develop an ankle NP specifically designed to work in the field of hybrid robotics. This article presents early steps towards this goal and makes a brief review about motor NPs and Functional Electrical Stimulation (FES) principles and most common devices used to aid the ankle functioning during the gait cycle. It also shows a current sources analysis done in this framework, in order to choose the best one for this intended application.

  7. Stem cell sources for tooth regeneration: current status and future prospects

    Directory of Open Access Journals (Sweden)

    Keishi eOtsu

    2014-02-01

    Full Text Available Stem cells are capable of renewing themselves through cell division and have the remarkable ability to differentiate into many different types of cells. They therefore have the potential to become a central tool in regenerative medicine. During the last decade, advances in tissue engineering and stem cell-based tooth regeneration have provided realistic and attractive means of replacing lost or damaged teeth. Investigation of embryonic and adult (tissue stem cells as potential cell sources for tooth regeneration has led to many promising results. However, technical and ethical issues have hindered the availability of these cells for clinical application. The recent discovery of induced pluripotent stem (iPS cells has provided the possibility to revolutionize the field of regenerative medicine (dentistry by offering the option of autologous transplantation. In this article, we review the current progress in the field of stem cell-based tooth regeneration and discuss the possibility of using iPS cells for this purpose.

  8. Stem cell sources for tooth regeneration: current status and future prospects.

    Science.gov (United States)

    Otsu, Keishi; Kumakami-Sakano, Mika; Fujiwara, Naoki; Kikuchi, Kazuko; Keller, Laetitia; Lesot, Hervé; Harada, Hidemitsu

    2014-01-01

    Stem cells are capable of renewing themselves through cell division and have the remarkable ability to differentiate into many different types of cells. They therefore have the potential to become a central tool in regenerative medicine. During the last decade, advances in tissue engineering and stem cell-based tooth regeneration have provided realistic and attractive means of replacing lost or damaged teeth. Investigation of embryonic and adult (tissue) stem cells as potential cell sources for tooth regeneration has led to many promising results. However, technical and ethical issues have hindered the availability of these cells for clinical application. The recent discovery of induced pluripotent stem (iPS) cells has provided the possibility to revolutionize the field of regenerative medicine (dentistry) by offering the option of autologous transplantation. In this article, we review the current progress in the field of stem cell-based tooth regeneration and discuss the possibility of using iPS cells for this purpose.

  9. Estimation of the Plant Time Constant of Current-Controlled Voltage Source Converters

    DEFF Research Database (Denmark)

    Vidal, Ana; Yepes, Alejandro G.; Malvar, Jano

    2014-01-01

    Precise knowledge of the plant time constant is essential to perform a thorough analysis of the current control loop in voltage source converters (VSCs). As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included...... of the VSC interface filter measured at rated conditions. This paper extends that method so that both parameters of the plant time constant (resistance and inductance) are estimated. Such enhancement is achieved through the evaluation of the closed-loop transient responses of both axes of the synchronous...... in the model, through an equivalent series resistance. In a recent work, an algorithm to identify this parameter was developed, considering the inductance value as known and practically constant. Nevertheless, the plant inductance can also present important uncertainties with respect to the inductance...

  10. The adequacy of current import and export controls on sealed radioactive sources.

    Energy Technology Data Exchange (ETDEWEB)

    Longley, Susan W.; Cochran, John Russell; Price, Laura L. (Beta Corporation, Glendale, AZ); Lipinski, Kendra J.

    2003-10-01

    Millions of sealed radioactive sources (SRSs) are being used for a wide variety of beneficial purposes throughout the world. Security experts are now concerned that these beneficial SRSs could be used in a radiological dispersion device to terrorize and disrupt society. The greatest safety and security threat is from those highly radioactive Category 1 and 2 SRSs. Without adequate controls, it may be relatively easy to legally purchase a Category 1 or 2 SRS on the international market under false pretenses. Additionally, during transfer, SRSs are particularly susceptible to theft since the sources are in a shielded and mobile configuration, transportation routes are predictable, and shipments may not be adequately guarded. To determine if government controls on SRS are adequate, this study was commissioned to review the current SRS import and export controls of six countries. Canada, the Russian Federation, and South Africa were selected as the exporting countries, and Egypt, the Philippines, and the United States were selected as importing countries. A detailed review of the controls in each country is presented. The authors found that Canada and Russia are major exporters, and are exporting highly radioactive SRSs without first determining if the recipient is authorized by the receiving country to own and use the SRSs. Available evidence was used to estimate that on average there are tens to possibly hundreds of intercountry transfers of highly radioactive SRSs each day. Based on these and other findings, this reports recommends stronger controls on the export and import of highly radioactive SRSs.

  11. Modeling left and right atrial contributions to the ECG: A dipole-current source approach.

    Science.gov (United States)

    Jacquemet, Vincent

    2015-10-01

    This paper presents the mathematical formulation, the numerical validation and several illustrations of a forward-modeling approach based on dipole-current sources to compute the contribution of a part of the heart to the electrocardiogram (ECG). Clinically relevant applications include identifying in the ECG the contributions from the right and the left atrium. In a Courtemanche-based monodomain computer model of the atria and torso, 1000 dipoles distributed throughout the atrial mid-myocardium are found to be sufficient to reproduce body surface potential maps with a relative error sources. In the presence of a right-left activation delay (sinus rhythm), pulmonary vein isolation (sinus rhythm) or left-right differences in refractory period (atrial fibrillation), the decomposition of the ECG is shown to help interpret ECG morphology in relation to the atrial substrate. These tools provide a theoretical basis for a deeper understanding of the genesis of the P wave or fibrillatory waves in normal and pathological cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. KAERI charged particle cross section library for radioisotope production

    CERN Document Server

    Chang, J H; Kim, D H; Lee, Y O; Zhuang, Y X

    2001-01-01

    This report summarized information and figures describing the 'KAERI Charged Particle Cross Section Library for Radioisotope production' The library contains proton-, deutron-, He-3-, and alpha-induced monitor cross sections, and gamma- and positron-emitter production cross sections. Experimental data and evaluation methods are described, and the evaluated cross sections are compared with those of the IAEA, MENDL, and LA150. The library has cross sections and emission spectra suitable for the transport analysis in the design of radioisotope production system, and are available at http://atom.kaeri.re.kr/ in ENDF-6 format.

  13. Mitigation of grid-current distortion for LCL-filtered grid-connected voltage-source inverter with inverter-side current control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2017-01-01

    Due to the low inductance of an LCL-filter, the grid current generated by an LCL-filtered Voltage Source Inverter (VSI) is sensitive to low-order grid-voltage harmonics. This issue is especially tough for the control system with Inverter Current Feedback (ICF), because the grid-current harmonics...... can freely flow into the filter capacitor without control. To cope with this issue, this paper develops an approach for the ICF control system to suppress the grid-current harmonics without adding extra sensors. The proposed method applies harmonic controllers and feedforward scheme simultaneously...

  14. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  15. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

    Science.gov (United States)

    Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

    2012-10-01

    Ultrasound current source density imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and seven cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012%/MPa, similar to the measurement of K in physiological saline (0.034±0.003%/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias.

  16. FPGA Control Implementation of a Grid-Connected Current-Controlled Voltage-Source Inverter

    Directory of Open Access Journals (Sweden)

    Rickard Ekström

    2013-01-01

    Full Text Available The full control system of a grid-connected current-controlled voltage-source inverter (CC-VSI has been designed and implemented on a field-programmable gate array (FPGA. Various control functions and implementation methods are described and discussed. The practical viability of the system is evaluated in an experimental setup, where a VSI supplies 30 kW into the local grid at 400 V. A phase-locked loop (PLL is used for grid phase tracking and evaluated for simulated abnormal grid conditions. Power factor is kept at unity, and the implemented control system is stressed with step responses in the supplied active power. A moving-average filter is implemented to reduce the effects of noise and harmonics on the current control loops. A coupling between active and reactive power flow is observed for the step responses but may be ignored in this context. The proposed system is fully comparable with more conventional microprocessor-based control systems.

  17. First test of BNL electron beam ion source with high current density electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, Alexander, E-mail: pikin@bnl.gov; Alessi, James G., E-mail: pikin@bnl.gov; Beebe, Edward N., E-mail: pikin@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard [CERN, CH-1211 Geneva 23 (Switzerland)

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  18. Production of medical radioisotopes in the ORNL High Flux Isotope Reactor (HFIR) for cancer treatment and arterial restenosis therapy after PTCA

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, F.F. Jr.; Beets, A.L.; Mirzadeh, S.; Alexander, C.W.; Hobbs, R.L.

    1998-06-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) represents an important resource for the production of a wide variety of medical radioisotopes. In addition to serving as a key production site for californium-252 and other transuranic elements, important examples of therapeutic radioisotopes which are currently routinely produced in the HFIR for distribution include dysprosium-166 (parent of holmium-166), rhenium-186, tin-117m and tungsten-188 (parent of rhenium-188). The nine hydraulic tube (HT) positions in the central high flux region permit the insertion and removal of targets at any time during the operating cycle and have traditionally represented a major site for production of medical radioisotopes. To increase the irradiation capabilities of the HFIR, special target holders have recently been designed and fabricated which will be installed in the six Peripheral Target Positions (PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and will be used for long-term irradiations, such as required for the production of tin-117m and tungsten-188. Each of the PTP tubes will be capable of housing a maximum of eight HT targets, thus increasing the total maximum number of HT targets from the current nine, to a total of 57. In this paper the therapeutic use of reactor-produced radioisotopes for bone pain palliation and vascular brachytherapy and the therapeutic medical radioisotope production capabilities of the ORNL HFIR are briefly discussed.

  19. COMPASS Final Report: Saturn Moons Orbiter Using Radioisotope Electric Propulsion (REP): Flagship Class Mission

    Science.gov (United States)

    Oleson, Steven R.; McGuire, Melissa L.

    2011-01-01

    The COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) team was approached by the NASA Glenn Research Center (GRC) In-Space Project to perform a design session to develop Radioisotope Electric Propulsion (REP) Spacecraft Conceptual Designs (with cost, risk, and reliability) for missions of three different classes: New Frontier s Class Centaur Orbiter (with Trojan flyby), Flagship, and Discovery. The designs will allow trading of current and future propulsion systems. The results will directly support technology development decisions. The results of the Flagship mission design are reported in this document

  20. 78 FR 1848 - Plutonium-238 Production for Radioisotope Power Systems for National Aeronautics and Space...

    Science.gov (United States)

    2013-01-09

    ... Plutonium-238 Production for Radioisotope Power Systems for National Aeronautics and Space Administration...-238 (Pu-238) for radioisotope power systems (RPSs) to support the National Aeronautics and Space... Radioisotope Power Systems (Draft Consolidation EIS) in 2005 to consolidate the nuclear operations related to...

  1. Cyclic irradiation method for production of radioisotope tracers using ...

    African Journals Online (AJOL)

    Cyclic Irradiation Method (CIM) involving repeated irradiation of samples at regular time intervals to build up activity has been adopted for the production of 82 Br, 72 Ga, 140La, 24 Na and 46 Sc isotopes using the low power Ghana Research Reactor-1. The results indicate that the specific activities of radioisotopes from ...

  2. Future Supply of Medical Radioisotopes for the UK Report 2014

    CERN Document Server

    Neilly, Brian; Ballinger, Jim; Buscombe, John; Clarke, Rob; Ellis, Beverley; Flux, Glenn; Fraser, Louise; Hall, Adrian; Owen, Hywel; Paterson, Audrey; Perkins, Alan; Scarsbrook, Andrew

    2015-01-01

    The UK has no research nuclear reactors and relies on the importation of 99Mo and other medical radioisotopes (e.g. Iodine-131) from overseas (excluding PET radioisotopes). The UK is therefore vulnerable not only to global shortages, but to problems with shipping and importation of the products. In this context Professor Erika Denton UK national Clinical Director for Diagnostics requested that the British Nuclear Medicine Society lead a working group with stakeholders including representatives from the Science & Technology Facilities Council (STFC) to prepare a report. The group had a first meeting on 10 April 2013 followed by a working group meeting with presentations on 9th September 2013 where the scope of the work required to produce a report was agreed. The objectives of the report are: to describe the status of the use of medical radioisotopes in the UK; to anticipate the potential impact of shortages for the UK; to assess potential alternative avenues of medical radioisotope production for the UK m...

  3. Novel MSVPWM to reduce the inductor current ripple for Z-source inverter in electric vehicle applications.

    Science.gov (United States)

    Zhang, Qianfan; Dong, Shuai; Xue, Ping; Zhou, Chaowei; Cheng, ShuKang

    2014-01-01

    A novel modified space vector pulse width modulation (MSVPWM) strategy for Z-Source inverter is presented. By rearranging the position of shoot-through states, the frequency of inductor current ripple is kept constant. Compared with existing MSVPWM strategies, the proposed approach can reduce the maximum inductor current ripple. So the volume of Z-source network inductor can be designed smaller, which brings the beneficial effect on the miniaturization of the electric vehicle controller. Theoretical findings in the novel MSVPWM for Z-Source inverter have been verified by experiment results.

  4. Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

    Energy Technology Data Exchange (ETDEWEB)

    Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

    1997-12-31

    Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

  5. Wild boars meat as a potential source of human trichinellosis in Poland: current data.

    Science.gov (United States)

    Moskwa, Bożena; Cybulska, Aleksandra; Kornacka, Aleksandra; Cabaj, Władysław; Bień, Justyna

    2015-09-01

    Trichinellosis is an epidemiological problem with a global distribution. In Poland a substantial increase of the wild boar population has been observed since 2010, together with an increased incidence of trichinellosis after ingestion of raw or undercooked wild boar products containing Trichinella spp. larvae. However, the actual number of human cases remains particularly difficult to determine. The aim of the present study was to determine the current prevalence and spread of these parasites within wild boars. The diaphragm pillars and tongue from 833 wild boars were collected from 2010 to 2014, as well as one wild boar meat sausage known to be a source of infection. The samples were tested for Trichinella spp. using pepsin digestion. Recovered larvae were identified at species level by multiplex polymerase chain reaction (multiplex PCR). The overall prevalence in all examined samples was found to be 2.0% (17/833). Recovered larvae were identified as T. spiralis and T. britovi (9/18 and 5/18, respectively). T. spiralis larvae were isolated from the sausage. Mixed infection was confirmed only once. Three isolates were not identified. The results of our study confirm that the wild boar plays a key role in the maintenance of Trichinella nematodes through the sylvatic cycle.

  6. Performance analysis of a low-cost current-source 1-ph grid-connected PV inverter

    OpenAIRE

    ERTAŞGIN, GÜRHAN; SOONG, WEN LIANG; ERTUGRUL, NESIMI

    2015-01-01

    This paper investigates the design and performance of a 150 W single-phase current-source grid-connected inverter topology that is based on a PV array and DC link inductor acting as a constant-current source. The inverter is implemented using a single boost switch, an H-bridge inverter, and a CL output filter. The inverter output current is simply controlled using the boost switch and open-loop or feedforward control. The dark I-V configuration is used to simulate two series PV modules. Compr...

  7. Production of medical radioisotopes in the ORNL high flux isotope reactor (HFIR) for cancer treatment and arterial restenosis therapy after PICA

    Science.gov (United States)

    Knapp, F. F.; Beets, A. L.; Mirzadeh, S.; Alexander, C. W.; Hobbs, R. L.

    1999-01-01

    The High Flux Isotope Reactor ( HFIR) at the Oak Ridge National Laboratory ( ORNL) represents an important resource for the production of a wide variety of medical radioisotopes. First beginning operation in 1965, the high thermal neutron flux (2.5×1015 neutrons/cm2/sec at 85 MW) and versatile target irradiation and handling facilities provide the opportunity for production of a wide variety of neutron-rich medical radioisotopes of current interest for therapy. In addition to serving as a key production site for californium-252 and other transuranic elements, important examples of therapeutic radioisotopes which are currently routinely produced in the HFIR for distribution include dysprosium-166 (parent of holmium-166), rhenium-186, tin-117 m and tungsten-188 (parent of rhenium-188). The nine hydraulic tube ( HT) positions in the central high flux region permit the insertion and removal of targets at any time during the operating cycle (22-24 days) and have traditionally represented a major site for production of medical radioisotopes. To increase the irradiation capabilities of the HFIR, special target holders have recently been designed and fabricated which will be installed in the six Peripheral Target Positions ( PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and will be used for long-term irradiations, such as required for the production of tin-117 m and tungsten-188. Each of the PTP tubes will be capable of housing a maximum of eight HT targets, thus increasing the total maximum number of HT targets from the current nine, to a total of 57. In this paper the therapeutic use of reactor-produced radioisotopes for bone pain palliation and vascular brachytherapy and the therapeutic medical radioisotope production capabilities of the ORNL HFIR are briefly discussed.

  8. Overview of current peculiarities of promotion of energy from renewable sources in Lithuania. Country reports: Lithuania

    OpenAIRE

    Griguolaitė, Rita

    2015-01-01

    This report provides an overview of the legal background and strategic planning of development and promotion of energy from renewable sources in Lithuania. It discusses the main provisions of the Law on Energy from Renewable Sources in the sectors of electricity, transport and heat. Also, established national financial incentives for the promotion of energy from renewable sources are described.

  9. Open Access, Open Source and Digital Libraries: A Current Trend in University Libraries around the World

    Science.gov (United States)

    Krishnamurthy, M.

    2008-01-01

    Purpose: The purpose of this paper is to describe the open access and open source movement in the digital library world. Design/methodology/approach: A review of key developments in the open access and open source movement is provided. Findings: Open source software and open access to research findings are of great use to scholars in developing…

  10. Simulation of a current source with a Cole-Cole load for multi-frequency electrical impedance tomography.

    Science.gov (United States)

    Aguiar Santos, Susana; Schlebusch, Thomas; Leonhardt, Steffen

    2013-01-01

    An accurate current source is one of the keys in the hardware of Electrical impedance Tomography systems. Limitations appear mainly at higher frequencies and for non-simple resistive loads. In this paper, we simulate an improved Howland current source with a Cole-Cole load. Simulations comparing two different op-amps (THS4021 and OPA843) were performed at 1 kHz to 1 MHz. Results show that the THS4021 performed better than the OPA843. The current source with THS4021 reaches an output impedance of 20 MΩ at 1 kHz and above 320 kΩ at 1 MHz, it provides a constant and stable output current up to 4 mA, in the complete range of frequencies, and for Cole-Cole (resistive and capacitive) load.

  11. Revealing smuggled nuclear material covered by a legitimate radioisotope shipment using CdTe-based gamma-ray spectrometry

    CERN Document Server

    Lakosi, L; Zsigrai, J; Safar, J

    2003-01-01

    Illicit trade of nuclear materials (NM) represents a serious challenge to radiation monitoring upon scenarios, when legitimate radioisotope shipments are used to obscure the weak radiation of NM. Planar and hemispherical Cd(Zn)Te detectors with a portable mini-multichannel analyzer were proven to be suitable, in measuring times of 10 min order, for revealing the presence of low-enriched or natural U-bearing reactor fuel pellets in amounts of kg order, placed beside transport containers of lead or depleted uranium, which contain high activity sup 6 sup 0 Co (10 GBq range) or sup 1 sup 9 sup 2 Ir (TBq range) radioisotope sources. Such a hand-held or portable device may help authorities combating illicit trafficking of nuclear materials.

  12. The Mars Hopper: Development, Simulation and Experimental Validation of a Radioisotope Exploration Probe for the Martian Surface

    Energy Technology Data Exchange (ETDEWEB)

    Nathan D. Jerred; Spencer Cooley; Robert C. O' Brien; Steven D. Howe; James E. O' Brien

    2012-09-01

    An advanced exploration probe has been proposed by the Center for Space Nuclear Research (CSNR) to acquire detailed data from the Martian surface and subsurface, ‘hop’ large distances to multiple sites in short periods of time and perform this task repeatedly. Although several similar flying vehicles have been proposed utilizing various power sources and complex designs, e.g. solar-electric and chemical-based, the CSNR’s Mars Hopper is based on a radioisotope thermal rocket (RTR) concept. The Mars Hopper’s design relies on the high specific energies [J/kg] of radioisotopes and enhances their low specific power [W/kg] through the use of a thermal capacitance material to store thermal energy over time. During operation, the RTR transfers the stored thermal energy to a flowing gas, which is then expanded through a converging-diverging nozzle, producing thrust. Between flights, the platform will have ample time to perform in-depth science at each location while the propellant tanks and thermal capacitor recharge. Recharging the propellant tanks is accomplished by sublimation freezing of the ambient CO2 atmosphere with a cryocooler, followed by heating and pressurization to yield a liquid storage state. The proposed Mars Hopper will undergo a ballistic flight, consuming the propellant in both ascent and descent, and by using multiple hopper platforms, information can be gathered on a global scale, enabling better resource resolution and providing valuable information for a possible Mars sample-return mission. The CSNR, collaborating with the Idaho National Laboratory (INL) and three universities (University of Idaho, Utah State University and Oregon State University), has identified key components and sub-systems necessary for the proposed hopper. Current project activities include the development of a lab-scale prototypic Mars Hopper and test facility, along with computational fluid dynamics (CFD)/thermal-hydraulic models to yield a better understanding of the

  13. Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter

    Science.gov (United States)

    Li, Qian

    Ultrasound Current Source Density Imaging (UCSDI) is a noninvasive modality for mapping electrical activities in the body (brain and heart) in 4-dimensions (space + time). Conventional cardiac mapping technologies for guiding the radiofrequency ablation procedure for treatment of cardiac arrhythmias have certain limitations. UCSDI can potentially overcome these limitations and enhance the electrophysiology mapping of the heart. UCSDI exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity. When an ultrasound beam intersects a current path in a material, the local resistivity of the material is modulated by the ultrasonic pressure, and a change in voltage signal can be detected based on Ohm's Law. The degree of modulation is determined by the AE interaction constant K. K is a fundamental property of any type of material, and directly affects the amplitude of the AE signal detected in UCSDI. UCSDI requires detecting a small AE signal associated with electrocardiogram. So sensitivity becomes a major challenge for transferring UCSDI to the clinic. This dissertation will determine the limits of sensitivity and resolution for UCSDI, balancing the tradeoff between them by finding the optimal parameters for electrical cardiac mapping, and finally test the optimized system in a realistic setting. This work begins by describing a technique for measuring K, the AE interaction constant, in ionic solution and biological tissue, and reporting the value of K in excised rabbit cardiac tissue for the first time. K was found to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart tissue, K was determined to be 0.041 +/- 0.012 %/MPa, similar to the measurement of K in physiologic saline: 0.034 +/- 0.003 %/MPa. Next, this dissertation investigates the sensitivity limit of UCSDI by quantifying the relation

  14. Mismatch Negativity in Recent-Onset and Chronic Schizophrenia: A Current Source Density Analysis

    Science.gov (United States)

    Fulham, W. Ross; Michie, Patricia T.; Ward, Philip B.; Rasser, Paul E.; Todd, Juanita; Johnston, Patrick J.; Thompson, Paul M.; Schall, Ulrich

    2014-01-01

    Mismatch negativity (MMN) is a component of the event-related potential elicited by deviant auditory stimuli. It is presumed to index pre-attentive monitoring of changes in the auditory environment. MMN amplitude is smaller in groups of individuals with schizophrenia compared to healthy controls. We compared duration-deviant MMN in 16 recent-onset and 19 chronic schizophrenia patients versus age- and sex-matched controls. Reduced frontal MMN was found in both patient groups, involved reduced hemispheric asymmetry, and was correlated with Global Assessment of Functioning (GAF) and negative symptom ratings. A cortically-constrained LORETA analysis, incorporating anatomical data from each individual's MRI, was performed to generate a current source density model of the MMN response over time. This model suggested MMN generation within a temporal, parietal and frontal network, which was right hemisphere dominant only in controls. An exploratory analysis revealed reduced CSD in patients in superior and middle temporal cortex, inferior and superior parietal cortex, precuneus, anterior cingulate, and superior and middle frontal cortex. A region of interest (ROI) analysis was performed. For the early phase of the MMN, patients had reduced bilateral temporal and parietal response and no lateralisation in frontal ROIs. For late MMN, patients had reduced bilateral parietal response and no lateralisation in temporal ROIs. In patients, correlations revealed a link between GAF and the MMN response in parietal cortex. In controls, the frontal response onset was 17 ms later than the temporal and parietal response. In patients, onset latency of the MMN response was delayed in secondary, but not primary, auditory cortex. However amplitude reductions were observed in both primary and secondary auditory cortex. These latency delays may indicate relatively intact information processing upstream of the primary auditory cortex, but impaired primary auditory cortex or cortico-cortical or

  15. Early effect of NEURAPAS® balance on current source density (CSD of human EEG

    Directory of Open Access Journals (Sweden)

    Koch Klaus

    2011-08-01

    Full Text Available Abstract Psychiatric patients often suffer from stress, anxiety and depression. Various plant extracts are known to fight stress (valerian, anxiety (passion flower or depression (St. John's wort. NEURAPAS® balance is a mixture of these three extracts and has been designed to cover this complex of psychiatric conditions. The study was initiated to quantitatively assess the effect of this combination on brain electric activity. Method Quantitative electroencephalogram (EEG current source density (CSD recording from 16 healthy male and female human volunteers (average age 49 years was used in a randomized, placebo-controlled cross over study. Recordings were performed 0. 5, 1. 5, 3 and 4 hours after administration of the preparations under the conditions of 6 min eyes open and 5 min d2 concentration test, mathematical calculation test and memory test, respectively. All variables (electric power within 6 frequency ranges at 17 electrode positions were fed into a linear discriminant analysis (eyes open condition. In the presence of mental load these variables were used to construct brain maps of frequency changes. Results Under the condition of mental load, centro-parietal spectral power remained statistically significantly lower within alpha1, alpha2 and beta1 frequencies in the presence of verum in comparison to placebo. Discriminant analysis revealed a difference to placebo 3 and 4 hours after intake of 6 tablets of NEURAPAS® balance. Data location within the polydimensional space was projected into the area of the effects of sedative and anti-depressive reference drugs tested earlier under identical conditions. Results appeared closer to the effects of fluoxetine than to St. John's wort. Conclusions Analysis of the neurophysiological changes following the intake of NEURAPAS® balance revealed a similarity of frequency changes to those of calming and anti-depressive drugs on the EEG without impairment of cognition. Trial registration Clinical

  16. Input and output filter design of current source PWM converter for high-precision magnet power supply

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Sung [Cheonan National Junior Technical College, Cheonan (Korea, Republic of); Choi, Jae Ho [Chungbuk National University, Chongju (Korea, Republic of)

    1996-01-01

    Current Source PWM converter is appropriate for the magnet power supply system which requests high power and high precision current control. Input and output filters should be installed to eliminate the current or voltage harmonics caused by the PWM switching for the current source PWM converter. But the input/output filters limit the output DC current range and may destroy the system with filter resonance, and make the system equation more complicated. In this paper, systematic and simple filter design method which considers not only the harmonic attenuation but also the total system good transfer function characteristics in the dc filter. The simulated and experimental results verify the proposed theory. (author). 14 refs., 12 figs., 8 tabs.

  17. Removal of Direct Current Link Harmonic Ripple in Single Phase Voltage Source Inverter Systems Using Supercapacitors

    Science.gov (United States)

    2016-09-01

    efficient and reliable sharing of grid loads by several disparate power sources, which allows alternative energy sources such as solar and wind energy to...from alternate power sources, such as a photovoltaic ( PV ) cell array , until needed. One of the many benefits of using an EMS with energy storage is...D. Lu, and B. Francois, “Power control design of a battery charger in a hybrid active PV generator for load -following applications,” IEEE

  18. Space Vector Modulation for DC-Link Current Ripple Reduction in Back-To-Back Current Source Converters for Microgrid Applications

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Xu, David; Guerrero, Josep M.

    2015-01-01

    Back-to-back converters have been typically used to interconnect the microgrids. For a back-to-back current source converter, the dc-link current ripple is one of the important parameters. A large ripple will cause the electromagnetic interference, undesirable high-frequency losses, and system in...... be significantly reduced by adjusting the gate patterns of space vector modulation (SVM) between the rectifier and inverter in a back-to-back converter. The experimental results verify the effectiveness of the proposed method....

  19. Radioisotope method of compound flow analysis

    Directory of Open Access Journals (Sweden)

    Petryka Leszek

    2015-01-01

    Full Text Available The paper presents gamma radiation application to analysis of a multicomponent or multiphase flow. Such information as a selected component content in the mixture transported through pipe is crucial in many industrial or laboratory installations. Properly selected sealed radioactive source and collimators, deliver the photon beam, penetrating cross section of the flow. Detectors mounted at opposite to the source side of the pipe, allow recording of digital signals representing composition of the stream. In the present development of electronics, detectors and computer software, a significant progress in know-how of this field may be observed. The paper describes application of this method to optimization and control of hydrotransport of solid particles and propose monitoring facilitating prevent of a pipe clogging or dangerous oscillations.

  20. Alpha-Energy-Deposition-Profiling of Radioisotope p-i-n Diodes for Power Generation

    Science.gov (United States)

    Cress, Cory; Raffaelle, Ryne

    2006-03-01

    The high energy density and long half-life of certain alpha-emitting radioisotopes enables viable and long-lived power supplies to be fabricated on the micro-scale. A design incorporating an InGaP p-i-n photovoltaic (PV) device that directly converts the kinetic energy of the alpha-particles into electricity represents both a scalable and efficient microsystem design. To better understand the relationship between the alpha-energy-deposition-profile (ADEP) and the maximum power conversion efficiency for this device structure, we have performed two systematic studies. In these studies, I-V characteristics for the InGaP PV device under alpha-flux are measured as a function of alpha source distance, and as function of aluminum film thickness (10 nm to 10 μm) which is deposited onto the surface of the PV device. Both techniques will alter the ADEP in relation to the active region of the PV device. These experimental results are compared to a theoretical model which utilizes Monte Carlo simulations and numerical calculations to determine the ADEP for the same device configuration. The understanding gained from this analysis has direct implications towards the fabrication of radioisotope microbatteries with structural characteristics that enable optimal power conversion efficiencies to be achieved.

  1. Radio-Isotope Identification Algorithms for NaI γ Spectra

    Directory of Open Access Journals (Sweden)

    Michael Hamada

    2009-03-01

    Full Text Available The performance of Radio-Isotope Identification (RIID algorithms using NaI-based γ spectroscopy is increasingly important. For example, sensors at locations that screen for illicit nuclear material rely on isotope identification using NaI detectors to distinguish innocent nuisance alarms, arising from naturally occurring radioactive material, from alarms arising from threat isotopes. Recent data collections for RIID testing consist of repeat measurements for each of several measurement scenarios to test RIID algorithms. It is anticipated that vendors can modify their algorithms on the basis of performance on chosen measurement scenarios and then test modified algorithms on data for other measurement scenarios. It is therefore timely to review the current status of RIID algorithms on NaI detectors. This review describes γ spectra from NaI detectors, measurement issues and challenges, current RIID algorithms, data preprocessing steps, the role and current quality of synthetic spectra, and opportunities for improvements.

  2. Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

    Science.gov (United States)

    Qureshi, T. R.; Chatwin, C. R.; Huber, N.; Zarafshani, A.; Tunstall, B.; Wang, Wei

    2010-04-01

    The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifiers. Under differing load conditions two different settings of the GIC are evaluated and the results are compared to show its performance settings. Whilst the study has shown that over a wide bandwidth (i.e. 100Hz - 100MHz) the output impedance is limited, operation over a more limited range offers output impedance in the Giga-ohm range, which can be considered as being infinite.

  3. A Battery-less Grid Connected Photovoltaic Power generation using Five-Level Common-Emitter Current-Source Inverter

    OpenAIRE

    Suroso Suroso; Winasis Winasis; Toshihiko Noguchi

    2014-01-01

    Renewable power generation using photovoltaic is very interesting to be developed to deal with the problems of conventional energy sources and environmental issues. The photovoltaic power generation can operate both in stand-alone and grid-connected operations. This paper presents an application of the five-level common-emitter current-source inverter (CE-CSI) for grid connected photovoltaic system without batteries as energy storage system. In the proposed system, the five-level CE-CSI works...

  4. High Current, High Density Arc Plasma as a New Source for WiPAL

    Science.gov (United States)

    Waleffe, Roger; Endrizzi, Doug; Myers, Rachel; Wallace, John; Clark, Mike; Forest, Cary; WiPAL Team

    2016-10-01

    The Wisconsin Plasma Astrophysics Lab (WiPAL) has installed a new array of nineteen plasma sources (plasma guns) on its 3 m diameter, spherical vacuum vessel. Each gun is a cylindrical, molybdenum, washer-stabilized, arc plasma source. During discharge, the guns are maintained at 1.2 kA across 100 V for 10 ms by the gun power supply establishing a high density plasma. Each plasma source is fired independently allowing for adjustable plasma parameters, with densities varying between 1018 -1019 m-3 and electron temperatures of 5-15 eV. Measurements were characterized using a 16 tip Langmuir probe. The plasma source will be used as a background plasma for the magnetized coaxial plasma gun (MCPG), the Terrestrial Reconnection Experiment (TREX), and as the plasma source for a magnetic mirror experiment. Temperature, density, and confinement results will be presented. This work is supported by the DoE and the NSF.

  5. Safety evaluation on use and waste of medical radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jang Hee; Chung, Y. Y.; Chun, J. H.; Ahn, H. Y.; Lee, G. B.; Park, J. O.; Oh, G. B.; Hong, C. S.; Kim, G. S. [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    2001-03-15

    This study was performed a survey of many hospitals using radioisotopes in order to check the amount of use and used radioisotopes, radioactive waste, status of radiation safety and control and the exposure of radiation workers who are working at department of nuclear medicine. At the time of the survey, this study is provided as a guide to the safe handling radionuclides. It will prove helpful all users. The basic objective of radiation safety technique and national standardization of safe handling radioactive materials are to keep the radiation dose to man as low as are under any regulation within the annual dose limits recommended by Most. Further routine monitoring of I-131 high dose therapy ward was carried out the effectiveness of safety precautions taken to prevent undue release of I-131 to the environment.

  6. Californium-252: a remarkable versatile radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Osborne-Lee, I.W.; Alexander, C.W.

    1995-10-10

    A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

  7. Analysis of status of radiation/radioisotopes utilization

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Hee; Lee, Seung Hyun; Kim, Na Kyung; Kim, Kon Wuk [Business Innovation Office, Korean Association for Radiation Application, Seoul (Korea, Republic of)

    2017-03-15

    The use of radiation and radioisotopes in Korea has been increasing each year, and its impact on economy and industry is expected to be increasing progressively following the development of industrial technology and the expansion of their usage. To establish and supporting policies for industries using radiation and radioisotopes, it is necessary to check the status of related industries accurately, as well as to gather data required to establish plans for industrial development by studying both revenues and economic scale (contributing to revenue). o analyze the status of utilization, surveys were carried out on 6,621 organizations engaged in nuclear operations handling radiation and radioisotopes pursuant to the Nuclear Safety Act as of end 2014, on 33,471 medical institutions using radiation generators for medical and diagnostic purposes pursuant to the Medical Service Act, and on 2,218 organizations using radiation generators for animal diagnostics pursuant to the Veterinary License Act. he overall status of the domestic radiation market including the number of user organizations, that of employees, and the size of distributions (imports, productions, and exports) with which the scale of domestic radiation market can be judged showed a growth trend compared to the previous year, though the number of employees for radiation operation in industrial sector, research sector, education sector, military sector, and power plants (nuclear power plants) and the size of imports was reduced somewhat. t is expected that data acquired through periodic surveys on the status of utilization would be utilized practically in establishing governmental policies related to the promotion of usage of radiation and radioisotopes, and also be utilized widely in cultivating and developing the industry efficiently to invigorate the related industries.

  8. Subthreshold Current and Swing Modeling of Gate Underlap DG MOSFETs with a Source/Drain Lateral Gaussian Doping Profile

    Science.gov (United States)

    Singh, Kunal; Kumar, Sanjay; Goel, Ekta; Singh, Balraj; Kumar, Mirgender; Dubey, Sarvesh; Jit, Satyabrata

    2017-01-01

    This paper proposes a new model for the subthreshold current and swing of the short-channel symmetric underlap ultrathin double gate metal oxide field effect transistors with a source/drain lateral Gaussian doping profile. The channel potential model already reported earlier has been utilized to formulate the closed form expression for the subthreshold current and swing of the device. The effects of the lateral straggle and geometrical parameters such as the channel length, channel thickness, and oxide thickness on the off current and subthreshold slope have been demonstrated. The devices with source/drain lateral Gaussian doping profiles in the underlap structure are observed to be highly resistant to short channel effects while improving the current drive. The proposed model is validated by comparing the results with the numerical simulation data obtained by using the commercially available ATLAS™, a two-dimensional (2-D) device simulator from SILVACO.

  9. Direct Conversion of Radioisotope Energy to Electricity

    Energy Technology Data Exchange (ETDEWEB)

    Marks Prelas; Alexey Spitsyn; Alejandro Suarez; Eric Stienfelds; Dickerson Moreno; Bia-Ling Hsu; Tushar Ghosh; Robert Tompson; Sudarshan Loyalka; Dabir Viswanath

    2003-09-09

    A new chemical reactor has been tested for Field Enhanced Diffusion by Optical Activation doping and purification of SiC, GaN and AlN films. Different conditions have been used on SiC, GaN and AlN samples including temperature variation, electrical field variation, variations in electrical current and optical activation. A 5mW (630-680) nm laser was used for optical activation. It was observed that optical activation has a major effect on ion drift rates. It was also observed that the magnitude of the electrical current also enhanced ion drift rates by a postulated current drag mechanism. I-V characteristic curves were measured to verify changes in the electrical properties of the samples SIMS was used to analyze the concentrations of impurities in the film samples before and after treatment. It has been demonstrated that the field-enhanced diffusion by optical activation method can dope and purify the films. As a result, the electrical properties of the wafers have been significantly improved during treatment especially in cases where a laser is used.

  10. Prevention of significant deterioration permit application for the Fueled Clad Fabrication System, the Radioisotope Power Systems Facility, and the Fuel Assembly Area

    Energy Technology Data Exchange (ETDEWEB)

    1989-08-01

    This New Source Review'' has been submitted by the US Department of Energy-Richland Operations Office (PO Box 550, Richland, Washington 99352), pursuant to WAC 173-403-050 and in compliance with the Department of Ecology Guide to Processing A Prevention Of Significant Deterioration (PSD) Permit'' for three new sources of radionuclide emissions at the Hanford Site in Washington State. The three new sources, the Fueled Clad Fabrication System (FCFS), the Radioisotope Power Systems Facility (RPSF), and the Fuel Assembly Area (FAA), will be located in one facility, the Fuels and Materials Examination Facility (FMEF) of the 400 Area. The FMEF was originally designed to provide for post-irradiation examination and fabrication of breeder reactor fuels. These FMEF missions were cancelled before the introduction of any fuel materials or any irradiated material. The current plans are to use the facility to fabricate power supplies for use in space applications and to produce Fast Flux Test Facility (FFTF) fuel and target assemblies. The FCFS and the RPSF will produce materials and assemblies for application in space. The FAA project will produce FFTF fuel and target assemblies. The FCFS and the RPSF will share the same building, stack, and, in certain cases, the same floor space. Given this relationship, these systems will be dealt with separately to the extent possible. The FAA is a comparatively independent operation though it will share the FMEF complex.

  11. Radioisotope Electric Propulsion Centaur Orbiter Spacecraft Design Overview

    Science.gov (United States)

    Oleson, Steve; McGuire, Melissa; Sarver-Verhey, Tim; Juergens, Jeff; Parkey, Tom; Dankanich, John; Fiehler, Doug; Gyekenyesi, John; Hemminger, Joseph; Gilland, Jim; hide

    2009-01-01

    Radioisotope electric propulsion (REP) has been shown in past studies to enable missions to outerplanetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass radioisotope power systems (RPS) and light spacecraft (S/C) components. In order to determine what are the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers cost cap. The design shows that an orbiter using several long lived (approximately 200 kg Xenon throughput), low power (approximately 700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the New Frontiers cost cap. Optimal specific impulses for the Hall thrusters were found to be around 2000 sec with thruster efficiencies over 40%. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be reused to enhance science and simplify communications.

  12. Development of a Power Electronics Controller for the Advanced Stirling Radioisotope Generator

    Science.gov (United States)

    Leland, Douglas K.; Priest, Joel F.; Keiter, Douglas E.; Schreiber, Jeffrey G.

    2008-01-01

    Under a U.S. Department of Energy program for radioisotope power systems, Lockheed Martin is developing an Engineering Unit of the Advanced Stirling Radioisotope Generator (ASRG). This is an advanced version of the previously reported SRG110 generator. The ASRG uses Advanced Stirling Convertors (ASCs) developed by Sunpower Incorporated under a NASA Research Announcement contract. The ASRG makes use of a Stirling controller based on power electronics that eliminates the tuning capacitors. The power electronics controller synchronizes dual-opposed convertors and maintains a fixed frequency operating point. The controller is single-fault tolerant and uses high-frequency pulse width modulation to create the sinusoidal currents that are nearly in phase with the piston velocity, eliminating the need for large series tuning capacitors. Sunpower supports this effort through an extension of their controller development intended for other applications. Glenn Research Center (GRC) supports this effort through system dynamic modeling, analysis and test support. The ASRG design arrived at a new baseline based on a system-level trade study and extensive feedback from mission planners on the necessity of single-fault tolerance. This paper presents the baseline design with an emphasis on the power electronics controller detailed design concept that will meet space mission requirements including single fault tolerance.

  13. A new method of measuring renal function in conscious rats without the use of radioisotopes.

    Science.gov (United States)

    Gabel, R A; Ranaei, R A; Kivlighn, S D

    1996-12-01

    The purpose of the current experiment was to develop fast and accurate assays for measuring glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). An enzymatic method was developed for the determination of inulin, and a colorimetric method was developed for determination of p-aminohippurate (PAH) in the plasma and urine of rats. These assays are easily automated and do not require the use of radioisotopes or corrosive chemicals. Glomerular filtration rate was measured by the clearance of inulin, and effective renal plasma flow was measured by the clearance of PAH. Blood pressure, heart rate, and renal function (urine volume, electrolytes, GFR, and ERPF) were measured in conscious rats for 1.5 h prior to drug treatment and for 3 h after treatment. Baseline renal function was compared to historical data. Acute changes in GFR and ERPF following administration of the vasoconstrictor peptide endothelin-1 (ET-1) were accurately measured with results similar to those obtained with older methodologies. These new methods offer many advantages over previously described methods by eliminating the use of radioisotopes and harsh chemicals. In addition, these methods can be used with an automated instrument with high accuracy and precision. Therefore, these new methods can be used to accurately determine GFR and ERPF and are sensitive enough to detect acute changes in GFR and ERPF in conscious animals.

  14. A Circulating-Current Suppression Method for Parallel-Connected Voltage-Source Inverters With Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid...... applications. The basic concept of the proposed circulating-current suppression method is to modify the original current references by using the current difference among the parallel inverters. In the proposed approach, both of cross circulating-current and zero-sequence circulating-current are considered......, and added into the conventional droop plus virtual impedance control. In the control architecture, the reference voltages of the inverters are generated by the primary control loop which consists of a droop control and a virtual impedance. The secondary control is used to compensate the voltage drop...

  15. A Circulating Current Suppression Method for Parallel Connected Voltage-Source-Inverters (VSI) with Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    This paper describes a theoretical with experiment study on a control strategy for the parallel operation of threephase voltage source inverters (VSI), to be applied to uninterruptible power systems (UPS). A circulating current suppression strategy for parallel VSIs is proposed in this paper based...... on circulating current control loops used to modify the reference currents by compensating the error currents among parallel inverters. Both of the cross and zero-sequence circulating currents are considered. The proposed method is coordinated together with droop and virtual impedance control. In this paper......, droop control is used to generate the reference voltage of each inverter, and the virtual impedance is used to fix the output impedance of the inverters. In addition, a secondary control is used in order to recover the voltage deviation caused by the virtual impedance. And the auxiliary current control...

  16. Designing display primaries with currently available light sources for UHDTV wide-gamut system colorimetry

    National Research Council Canada - National Science Library

    Masaoka, Kenichiro; Nishida, Yukihiro; Sugawara, Masayuki

    2014-01-01

    .... Although monochromatic light sources are required for a display to perfectly fulfill the system colorimetry, highly saturated emission colors using recent quantum dot technology may effectively achieve the wide gamut...

  17. Ion current detector for high pressure ion sources for monitoring separations

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.D.; Wahl, J.H.; Hofstadler, S.A.

    1996-08-13

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source. 7 figs.

  18. Ion current detector for high pressure ion sources for monitoring separations

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard D. (Richland, WA); Wahl, Jon H. (Richland, WA); Hofstadler, Steven A. (Richland, WA)

    1996-01-01

    The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source.

  19. BIOMASS UTILIZATION AS A RENEVABLE ENERGY SOURCE IN POLISH POWER INDUSTRY – CURRENT STATUS AND PERSPECTIVES

    Directory of Open Access Journals (Sweden)

    Beata Gołuchowska

    2015-06-01

    Full Text Available The depletion of the conventional energy sources, as well as the degradation and pollution of the environment by the exploitation of fossil fuels caused the development of renewable energy sources (RES, including biomass. In Poland, biomass is the most popular renewable energy source, which is closely related to the obligations associated with the membership in the EU. Biomass is the oldest renewable energy source, and its potential, diversity and polymorphism place it over other sources. Besides, the improvement in its parameters, including an increase in its calorific value, resulted in increasing use of biomass as energy source. In the electric power industry biomass is applied in the process of co-combustion with coal. This process may contribute, inter alia, to the reduction in the emissions of carbon, nitrogen and sulfur oxides. The article presents the characteristics of the biomass burned in power boilers of one of the largest Polish power plants, located in Opole Province (Southern Poland. Besides, the impact of biomass on the installation of co-combustion, as well as the advantages and disadvantages of the co-combustion process not only in technological, but also environmental, economic and social aspects were described.

  20. Buck-Boost Current-Source Inverters With Diode-Inductor Network

    DEFF Research Database (Denmark)

    Gao, Feng; Liang, Chao; Loh, Poh Chiang

    2009-01-01

    This paper presents a number of novel currentsource inverters (CSIs) with enhanced current buck-boost capability. By adding a unique diode-inductor network between the inverter circuitry and current-boost elements, the proposed buck-boost CSIs demonstrate a doubling of current-boost capability......, as compared with other recently reported buck-boost CSIs. For controlling the proposed CSIs, two modulation schemes are designed for achieving either optimized harmonic performance or minimized commutation count without influencing the inverter current buck-boost gain. These theoretical findings were...

  1. Low-Cost Open-Source Voltage and Current Monitor for Gas Metal Arc Weld 3D Printing

    Directory of Open Access Journals (Sweden)

    A. Pinar

    2015-01-01

    Full Text Available Arduino open-source microcontrollers are well known in sensor applications for scientific equipment and for controlling RepRap 3D printers. Recently low-cost open-source gas metal arc weld (GMAW RepRap 3D printers have been developed. The entry-level welders used have minimal controls and therefore lack any real-time measurement of welder voltage or current. The preliminary work on process optimization of GMAW 3D printers requires a low-cost sensor and data logger system to measure welder current and voltage. This paper reports on the development of a low-cost open-source power measurement sensor system based on Arduino architecture. The sensor system was designed, built, and tested with two entry-level MIG welders. The full bill of materials and open source designs are provided. Voltage and current were measured while making stepwise adjustments to the manual voltage setting on the welder. Three conditions were tested while welding with steel and aluminum wire on steel substrates to assess the role of electrode material, shield gas, and welding velocity. The results showed that the open source sensor circuit performed as designed and could be constructed for <$100 in components representing a significant potential value through lateral scaling and replication in the 3D printing community.

  2. Analytical Method to Calculate the DC Link Current Stress in Voltage Source Converters

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

    2014-01-01

    for the applications with high line current ripple. The effect of the pulsewidth modulation (PWM) scheme on the rms value of the dc-link current is also studied and the analysis for continuous PWM and discontinuous PWM (DPWM) schemes is presented. The proposed analytical method is also verified experimentally....

  3. Computation and Analysis of the Global Distribution of the Radioxenon Isotope 133Xe based on Emissions from Nuclear Power Plants and Radioisotope Production Facilities and its Relevance for the Verification of the Nuclear-Test-Ban Treaty

    Science.gov (United States)

    Wotawa, Gerhard; Becker, Andreas; Kalinowski, Martin; Saey, Paul; Tuma, Matthias; Zähringer, Matthias

    2010-05-01

    Monitoring of radioactive noble gases, in particular xenon isotopes, is a crucial element of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The capability of the noble gas network, which is currently under construction, to detect signals from a nuclear explosion critically depends on the background created by other sources. Therefore, the global distribution of these isotopes based on emissions and transport patterns needs to be understood. A significant xenon background exists in the reactor regions of North America, Europe and Asia. An emission inventory of the four relevant xenon isotopes has recently been created, which specifies source terms for each power plant. As the major emitters of xenon isotopes worldwide, a few medical radioisotope production facilities have been recently identified, in particular the facilities in Chalk River (Canada), Fleurus (Belgium), Pelindaba (South Africa) and Petten (Netherlands). Emissions from these sites are expected to exceed those of the other sources by orders of magnitude. In this study, emphasis is put on 133Xe, which is the most prevalent xenon isotope. First, based on the emissions known, the resulting 133Xe concentration levels at all noble gas stations of the final CTBT verification network were calculated and found to be consistent with observations. Second, it turned out that emissions from the radioisotope facilities can explain a number of observed peaks, meaning that atmospheric transport modelling is an important tool for the categorization of measurements. Third, it became evident that Nuclear Power Plant emissions are more difficult to treat in the models, since their temporal variation is high and not generally reported. Fourth, there are indications that the assumed annual emissions may be underestimated by factors of two to ten, while the general emission patterns seem to be well understood. Finally, it became evident that 133Xe sources mainly influence the sensitivity of the

  4. Computation of magnetic fields within source regions of ionospheric and magnetospheric currents

    DEFF Research Database (Denmark)

    Engels, U.; Olsen, Nils

    1998-01-01

    A general method of computing the magnetic effect caused by a predetermined three-dimensional external current density is presented. It takes advantage of the representation of solenoidal vector fields in terms of toroidal and poloidal modes expressed by two independent series of spherical...... harmonics. In order to rest the method, it is applied to two ionospheric-magnetospheric model current densities. The first example assumes a special large-scale current system which has an analytical solution for the magnetic field everywhere. In the second example, the results for a model current...... distribution that is of small-scale at high latitudes are compared with a direct integration using Biot-Savart's law. It is demonstrated that the method provides a fast and numerically stable determination of the magnetic field both outside and inside the current density....

  5. A study on the enhancement of nuclear cooperation with African countries including utilization of radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Maeng Ho; Oh, K. B; Lee, H. M. and others

    2005-05-15

    In this study, potential countries for nuclear cooperation in African region and possible cooperation areas were investigated between Korea and African countries including radioisotopes and more fields were also analysed in depth in order to suggest the recommendations for future cooperation to be considered as follows; First, current status and perspectives of demand and supply of energy and electricity in the African countries, use and development of nuclear energy and international nuclear cooperation were analyzed. Second, current status of nuclear cooperation between Korea and African countries were investigated as well as analysis of future cooperation potential and countries having potential for nuclear cooperation and possible cooperative activities were suggested considering potential of nuclear market in mid- and long term base and step by step. Third, desirable strategies and directions for the establishment and promotion of nuclear cooperation relations between Korea and African developing countries were suggested in order to develope cooperative relations in efficient and effective manners with African developing countries.

  6. Automated processing of first-pass radioisotope ventriculography data to determine essential central circulation parameters

    Science.gov (United States)

    Krotov, Aleksei; Pankin, Victor

    2017-09-01

    The assessment of central circulation (including heart function) parameters is vital in the preventive diagnostics of inherent and acquired heart failures and during polychemotherapy. The protocols currently applied in Russia do not fully utilize the first-pass assessment (FPRNA) and that results in poor data formalization, while the FPRNA is the one of the fastest, affordable and compact methods among other radioisotope diagnostics protocols. A non-imaging algorithm basing on existing protocols has been designed to use the readings of an additional detector above vena subclavia to determine the total blood volume (TBV), not requiring blood sampling in contrast to current protocols. An automated processing of precordial detector readings is presented, in order to determine the heart strike volume (SV). Two techniques to estimate the ejection fraction (EF) of the heart are discussed.

  7. The effect of the random distribution of electronic components in the output characteristics of the Howland current source

    Science.gov (United States)

    Bertemes-Filho, P.; Felipe, A.

    2013-04-01

    When a Howland source is designed, the components are chosen so that the designed source has the desired characteristics. However, the operational amplifier limitations and resistor tolerances causes undesired behaviours. This work proposes to take in account the influence of the random distribution of the commercial resistors in the Howland circuit over the frequency range of 10 Hz to 10 MHz. The probability density function due to small changes over the resistors was calculated by using an analytical model. Results show that both output current and impedance are very sensitive to the resistor tolerances. It is shown that the output impedance is very dependent on the open-loop gain of the Opamp rather than the resistor tolerances, especially at higher frequencies. This might improve the implementations of real current source used in electrical bioimpedance.

  8. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  9. Designing display primaries with currently available light sources for UHDTV wide-gamut system colorimetry.

    Science.gov (United States)

    Masaoka, Kenichiro; Nishida, Yukihiro; Sugawara, Masayuki

    2014-08-11

    The wide-gamut system colorimetry has been standardized for ultra-high definition television (UHDTV). The chromaticities of the primaries are designed to lie on the spectral locus to cover major standard system colorimetries and real object colors. Although monochromatic light sources are required for a display to perfectly fulfill the system colorimetry, highly saturated emission colors using recent quantum dot technology may effectively achieve the wide gamut. This paper presents simulation results on the chromaticities of highly saturated non-monochromatic light sources and gamut coverage of real object colors to be considered in designing wide-gamut displays with color filters for the UHDTV.

  10. DC link current simulation of voltage source inverter with random space vector pulse width modulation

    Directory of Open Access Journals (Sweden)

    Chen Guoqiang

    2016-01-01

    Full Text Available Aiming at analysis complexity, a simulation model is built and presented to analyze and demonstrate the characteristics of the direct current (DC link current of the three-phase two-level inverter with the random space vector pulse width modulation (SVPWM strategy. The developing procedure and key subsystems of the simulation model are given in detail. Several experiments are done using the simulation model. The results verify the efficiency and convenience of the simulation model and show that the random SVPWM scheme, especially the random switching frequency scheme, can efficiently suppress the harmonic peaks of the DC link current.

  11. Designing high-order power-source synchronous current converters for islanded and grid-connected microgrids

    DEFF Research Database (Denmark)

    Ashabani, Mahdi; Gooi, Hoay Beng; Guerrero, Josep M.

    2018-01-01

    This paper deals with development of a versatile and compact control strategy for voltage source converters in grid-connected and islanded microgrids using synchronous current converters technology. The key feature is its new integrated high-order controller/synchronizer with applicability to both...... operational modes without strategy rearrangement. Using high-order controllers, on the other hand, results in rather complex analysis and design process, therefore this paper aims at providing a general and simple theme for the design and parameter selection. The controller also provides adaptive...... and automated current-based grid synchronization. Moreover, the controller realizes a power-source current-controlled microgrid with minimum control loops, as compared to widely adopted voltage controlled microgrids in the literature, with advantages such as fault-ride-through and inherent droop-less power...

  12. Brachytherapy on restenosis. {sup 32}P radioisotope in animal model

    Energy Technology Data Exchange (ETDEWEB)

    Bergoc, R.; Rivera, E.; Cocca, C.; Martin, G.; Cricco, G. [Buenos Aires Univ. (Argentina). School of Pharmacy and Biochemistry; Croci, M.; Guzman, L.

    2000-05-01

    Despite a notorious decline in age-adjusted death rates for cardiovascular pathologies, coronary artery disease still remains as the main cause of mortality above the age of 40 in men and 60 in women. More than 25% of death in persons over the age of 35 are due to coronary disease. In about 50% of men and 30% of women, the first manifestation of the disease is an acute myocardial infarction and 10% a sudden cardiac death. In Argentina it is estimated that in 1998 about 100.000-115.000 people suffered as first manifestation of coronary illness a myocardial acute infarct. Angioplasty has an important and well established site in the treatment of the coronary illness and restenosis represents the principal complication of this method for myocardial re-vascularization. About a 35-40% of treated arteries present restenosis within the first six month the intervention with the concomitant need of re-interventions, re-hospitalizations, by-pass surgery, work discontinuity and the high cost for the health system. A number of drugs were tested as anti-restenosis: anticoagulants, aspirin, antispasmodics and lipid-lowering agents but none was clearly efficient; also, experimental studies in which intravascular irradiation with different source types and energies, radiation doses and doses rate to prevent restenosis was utilized; however, there is no consensus in many aspects of this intravascular brachytherapy. The first step in this work was to induce the experimental model in rabbits. Afterwards, by means of the balloon methodology and stent implantation, brachytherapy experiments were carried out to evaluate the biological effect on different layers of arteries, with different Doses using a beta particle emitting radioisotope ({sup 32}P). The arteriosclerotic lesions were induced in New Zealand rabbits through the administration of a diet with high cholesterol content. Angioplastic interventions on femoral arteries were done with balloon methodology and controlled by

  13. Development of the cyclotron radioisotope production technology

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Sup; Chun, K.S.; Yang, S.D.; Lee, J.D.; Ahn, S.H.; Yun, Y.K.; Park, H.; Lee, J.S.; Chai, J.S.; Kim, U.S.; Hong, S.S.; Lee, M.Y.; Park, C.W.; Baik, S. K.; Kim, E. H.; Kim, T. K.; Kim, K. S.; Kim, J. H

    1999-04-01

    The purpose of this study is to contribute the advance of nuclear medicine and to the improvement of human health through the development of various accelerator radionuclides and mass production with automization of production. The results obtained from this study are following: 1) In order to introduce 30 MeV high current cyclotron, the specification of cyclotron has been made, the building site was selected and we drew the draw-up of cyclotron. The cyclotron installation contract was postponed until the financial resources could be secured. 2) For a development high purity 1-123 producing system, a Xe-124 target system, a temperature measurement system of the inner part of the target and a target window were fabricated. A Xe-124 gas target recovery system and a full production system of 1-123 was drew up. 3) For a development of a therapeutic nuclide At-211, a target for the production of At-211 via {sup 209}Bi(alpha, 2n) reaction was fabricated. Produced At-211 was separated by distillation method. 4) For development of beta-emitting nuclides, Ti-45, C-11, F{sub 2}-18, beam irradiation system suitable for each target were fabricated. 5) For automatic production of Ga-67, automated module and PLC program was made 6) For the quality control of radiopharmaceuticals, analytical method of thallium and copper by polarography was investigated and established.

  14. Maximum current density and beam brightness achievable by laser-driven electron sources

    Directory of Open Access Journals (Sweden)

    D. Filippetto

    2014-02-01

    Full Text Available This paper discusses the extension to different electron beam aspect ratio of the Child-Langmuir law for the maximum achievable current density in electron guns. Using a simple model, we derive quantitative formulas in good agreement with simulation codes. The new scaling laws for the peak current density of temporally long and transversely narrow initial beam distributions can be used to estimate the maximum beam brightness and suggest new paths for injector optimization.

  15. Maximum current density and beam brightness achievable by laser-driven electron sources

    Science.gov (United States)

    Filippetto, D.; Musumeci, P.; Zolotorev, M.; Stupakov, G.

    2014-02-01

    This paper discusses the extension to different electron beam aspect ratio of the Child-Langmuir law for the maximum achievable current density in electron guns. Using a simple model, we derive quantitative formulas in good agreement with simulation codes. The new scaling laws for the peak current density of temporally long and transversely narrow initial beam distributions can be used to estimate the maximum beam brightness and suggest new paths for injector optimization.

  16. Control of mercury emissions from stationary coal combustion sources in China: Current status and recommendations.

    Science.gov (United States)

    Hu, Yuanan; Cheng, Hefa

    2016-11-01

    Coal burning in power plants and industrial boilers is the largest combustion source of mercury emissions in China. Together, power plants and industrial boilers emit around 250 tonnes of mercury each year, or around half of atmospheric mercury emissions from anthropogenic sources in the country. Power plants in China are generally equipped with multi-pollutant control technologies, which offer the co-benefit of mercury removal, while mercury-specific control technologies have been installed in some facilities. In contrast, most industrial boilers have only basic or no flue gas cleaning. A combination of measures, including energy conservation, coal switching and blending, reducing the mercury contents of coals through washing, combustion controls, and flue gas cleaning, can be used to reduce mercury emissions from these stationary combustion sources. More stringent emission standards for the major air pollutants from coal-fired power plants and industrial boiler, along with standards for the previously unregulated mercury, were implemented recently, which is expected to bring significant reduction in their mercury emissions through the necessary upgrades of multi-pollutant and mercury-specific control technologies. Meanwhile, strong monitoring capacity and strict enforcement are necessary to ensure that the combustion sources operate in compliance with the new emission standards and achieve significant reduction in the emissions of mercury and other air pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Solid waste as renewable source of energy: current and future possibility in Libya

    Directory of Open Access Journals (Sweden)

    Tarek A. Hamad

    2014-11-01

    Full Text Available Solid waste holds the greatest potential as biomass source in Libya. The rapid expansion of industry has led to increased urbanization and growing population. These factors have dramatically increased the amount of MSW (municipal solid waste generated in Libya. However, issues related to environmentally sound MSW management—including waste decrease and clearance—have not been addressed sufficiently. This study presents an overview on solid waste that can be used as a source of bioenergy in Libya including MSW, ISW (industrial solid waste, and HSW (health care wastes as biomass sources. The management of solid waste and valorization is based on an understanding of MSW׳s composition and physicochemical characteristics. The results show that organic matter represents 59% of waste, followed by paper–cardboard 12%, plastic 8%, miscellaneous 8%, metals 7%, glass 4%, and wood 2%. The technology of WTE (waste-to-energy incineration, which recovers energy from discarded MSW and produces electricity and/or steam for heating, is recognized as a renewable source of energy and is playing an increasingly important role in MSW management in Libya. This paper provides an overview of this technology, including both its conversion options and its useful products (e.g., electricity, heat, greenhouse gas emissions. The WTE benefits and the major challenges in expanding WTE incineration in Libya are discussed. It also demonstrates that Libya could become an exporter of hydrogen in lieu of oil and natural gas.

  18. Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

    DEFF Research Database (Denmark)

    Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance......-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

  19. Advanced Stirling Radioisotope Generator Thermal Power Model in Thermal Desktop SINDA/FLUINT Analyzer

    Science.gov (United States)

    Wang, Xiao-Yen; Fabanich, William A.; Schmitz, Paul C.

    2012-01-01

    This paper presents a three-dimensional Advanced Stirling Radioisotope Generator (ASRG) thermal power model that was built using the Thermal Desktop SINDA/FLUINT thermal analyzer. The model was correlated with ASRG engineering unit (EU) test data and ASRG flight unit predictions from Lockheed Martin's Ideas TMG thermal model. ASRG performance under (1) ASC hot-end temperatures, (2) ambient temperatures, and (3) years of mission for the general purpose heat source fuel decay was predicted using this model for the flight unit. The results were compared with those reported by Lockheed Martin and showed good agreement. In addition, the model was used to study the performance of the ASRG flight unit for operations on the ground and on the surface of Titan, and the concept of using gold film to reduce thermal loss through insulation was investigated.

  20. Hysteresis Current Control of the Single-Phase Voltage Source Inverter Using eMEGAsim Real-Time Simulator

    Directory of Open Access Journals (Sweden)

    BOTEZAN, A.

    2015-08-01

    Full Text Available The paper presents the hysteresis current control of the voltage source inverter. The eMEGAsim real-time simulator is developed by OPAL-RT. Real-time simulation is used in many cases because it allows the behavior of the industrial processes operation to be determined. Two research directions are developed in this case, Rapid Control Prototyping and Hardware-In-the-Loop. Using eMEGAsim simulator allows implementing the command and control strategy of a single-phase voltage source inverter. At this stage, the real-time behavior of operation is monitored, because the voltage source inverter will be the part of a single-phase shunt active filter. In order to command and control the voltage source inverter, the current and voltage signals are acquired, since these signals are necessary to estimate reference signal. Extension of the Instantaneous Reactive Power Theorem is used because this theorem is suitable for single-phase active filter control. To test the real-time command and control strategy implemented, it was used a low power single-phase voltage source inverter (full bridge.

  1. Renewable energy sources for the world's poor: a review of current international development assistance programs

    Energy Technology Data Exchange (ETDEWEB)

    Ashworth, J. H.

    1979-10-01

    Foreign assistance funding of the creation, testing, and use of renewable energy sources concerning worldwide efforts to provide energy for Third World development is examined. Donor agencies and developing nations give serious attention to technologies that have been considered exotic and marginal: small-scale hydroelectric generation, solar water heating and distillation, biomass conversion to methane gas and alcohol, wind power, photovoltaic-powered small-scale irrigation, and village-level solar-powered absorption refrigeration. An initial effort to assist in the international coordination of donor activity and in the sharing of information generated by foreign-assistance projects that use renewable energy sources is reported. The report mainly provides information about specific development projects. It contains only a few of the projects that have been approved and funded by 1 June 1979. (MCW)

  2. Multiple-Stage Converter Topology for High-Precision High-Current Pulsed Sources

    CERN Document Server

    Wassinger, N; Benedetti, M; Carrica, D; Retegui, R G; Cravero, J M

    2011-01-01

    A new high-current, low-rise-time, and high-precision pulse generator is presented. The topology is based on the use of different stages, each one specific for a particular operation range in terms of power and switching frequency. This approach allows to accomplish current, voltage, and precision requirements with standard semiconductors. Moreover, the proposed topology provides an independent and flexible adjustment of the pulse parameters (rise and fall times, flat-top duration, pulse amplitude, etc.). Experimental results are provided to validate the control of the proposed topology.

  3. A New Method for Coupling the Potential Field Source Surface and the Schatten Current Sheet Models

    Science.gov (United States)

    2012-09-24

    Current Sheet Magnetic Model for the Solar Corona,” Cosmic Elecdyn., 2, 1971, pp. 232-245. [8] Fry, C. D., M. Dryer , Z. Smith, W. Sun, C. S. Deehr...with other models, to predict the global solar wind out past earth days in advance. It is routinely used for both AF and civilian space weather... solar radii above the Sun’s surface and (2) the Schatten Current Sheet (SCS) model used to project the solution out into the hypersonic interplanetary

  4. Converter-flux-based current control of voltage source PWM rectifiers - analysis and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Poellaenen, R.

    2003-07-01

    Pulsewidth-modulated (PWM) rectifier technology is increasingly used in industrial applications like variable-speed motor drives, since it offers several desired features such as sinusoidal input currents, controllable power factor, bidirectional power flow and high quality DC output voltage. To achieve these features, however, an effective control system with fast and accurate current and DC voltage responses is required. From various control strategies proposed to meet these control objectives, in most cases the commonly known principle of the synchronous-frame current vector control along with some space-vector PWM scheme have been applied. Recently, however, new control approaches analogous to the well-established direct torque control (DTC) method for electrical machines have also emerged to implement a high-performance PWM rectifier. In this thesis the concepts of classical synchronous-frame current control and DTC-based PWM rectifier control are combined and a new converter-flux-based current control (CFCC) scheme is introduced. To achieve sufficient dynamic performance and to ensure a stable operation, the proposed control system is thoroughly analysed and simple rules for the controller design are suggested. Special attention is paid to the estimation of the converter flux, which is the key element of converter-flux-based control. Discrete-time implementation is also discussed. Line-voltage-sensorless reactive reactive power control methods for the L- and LCL-type line filters are presented. For the L-filter an open-loop control law for the d-axis current reference is proposed. In the case of the LCL-filter the combined open-loop control and feedback control is proposed. The influence of the erroneous filter parameter estimates on the accuracy of the developed control schemes is also discussed. A new zero vector selection rule for suppressing the zero-sequence current in parallel-connected PWM rectifiers is proposed. With this method a truly standalone and

  5. Electrical conductivity of the hippocampal CA1 layers and application to current-source-density analysis

    NARCIS (Netherlands)

    Holsheimer, J.

    1987-01-01

    The microstructure of the layers in the hippocampal CA1 area suggests that differences may exist between the electrical conductivities of these layers. In order to quantify these differences a sinusoidal current was applied to hippocampal slices in a bathing medium and potential differences were

  6. Radioisotope synoviorthesis in paediatric and adolescent patients with haemophilia.

    Science.gov (United States)

    Martínez-Esteve, A; Álvarez-Pérez, R M; Núñez-Vázquez, R; Tirado-Hospital, J L; García-Jiménez, R; Povedano-Gómez, J; Borrego-Dorado, I

    2016-01-01

    To assess the outcome and adverse-effects of the radioisotope synoviorthesis in paediatric and adolescent patients with haemophilia. Prospective study of historical cohort was conducted. A total of 20 consecutive haemophiliacs with a mean age of 13.1 years (range 4-17) were included with a mean follow-up of 64.9 months (range 18-109). The diagnosis of synovitis was established on the basis of clinical follow-up including radiological images (radiography and/or MRI). For evaluation, the classification proposed by Fernandez-Palazzi was used. Patients aged less than 18 years old with haemophilia and more than one haemarthrosis in less than 3 months remaining a chronic synovitis despite prophylactic therapy intensification. Any contraindication for radionuclide synoviorthesis. Twenty-seven radioisotope synoviorthesis with (90)Y-citrate-colloid and/or (186)Re-sulphide-colloid were done. The effectiveness of the procedure was assessed through pre and posttreatment clinical comparison at 6 months after radioisotope synoviorthesis. Nineteen of the 27 synoviorthesis (70.3%) had a good or excellent response and 8 joints (29.7%) had partial response. It was necessary to repeat the procedure in 3 joints in 3 different patients, obtaining in all cases a good or excellent response. We appreciated inflammatory reaction after procedure in 4 cases (14.8%), which improved with analgesics and nonsteroidal anti-inflamatory drugs. None of the patients presented malignant or premalignant lesions during the follow-up. The radionuclide synoviorthesis is a very effective procedure in paediatric and adolescent patients with hemophilia, being a minimally invasive procedure, easy to perform, safe and with minimal side effects. Copyright © 2015 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

  7. Drugs and Drug Candidates from Marine Sources: An Assessment of the Current "State of Play".

    Science.gov (United States)

    Newman, David J; Cragg, Gordon M

    2016-06-01

    The potential of the marine environment to produce candidate compounds (structures) as leads to, or even direct drugs from, has been actively discussed for the last 50 or so years. Over this time frame, several compounds have led to drugs, usually in the area of cancer (due to funding sources). This review is designed to show where there have been successes, but also to show that in a number of disease areas, there are structures originally isolated from marine invertebrates and free-living microbes that have potential, but will need to be "adopted" by pharmaceutical houses in order to maximize their potential. Georg Thieme Verlag KG Stuttgart · New York.

  8. Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2013-08-01

    Full Text Available Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.

  9. Operation of a Fuzzy Controlled Half-Bridge DC-Converter as a Welding Current-Source

    Directory of Open Access Journals (Sweden)

    Kourosh Mahmoodi

    2012-03-01

    Full Text Available In This paper a new Fuzzy Controlled Welding current source is introduced and the results of the new control method are explained. The Fuzzy controller is applied to the welding machine to improve some problems of welding process. The new intelligent controller guaranties a constant current during welding to improve welding quality. It also provides some features such as hot-start and anti-stuck function and a standby mode for energy saving. The effectiveness of this intelligent welding machine was proven by the experimental results and durable test. The results show that designed FCWM (Fuzzy Controlled Welding Machine can be used in mobile welding industries.

  10. Operation and Modulation of H7 Current Source Inverter with Hybrid SiC and Si Semiconductor Switches

    DEFF Research Database (Denmark)

    Wang, Weiqi; Gao, Feng; Yang, Yongheng

    2018-01-01

    This paper proposes an H7 current source inverter (CSI) consisting of a single parallel-connected silicon carbide (SiC) switch and a traditional silicon (Si) H6 CSI. The proposed H7 CSI takes the advantages of the SiC switch to maintain high efficiency, while significantly increasing the switching...... frequency. In order to reduce the switching times and also realize the zero current switching (ZCS) ability for the rear-end CSI, two modulation schemes are proposed for the H7 CSI with either superior output performance or minimal switching counts. Consequently, the proposed H7 CSI can be considered...

  11. A new single-stage current source inverter for photovoltaic and fuel cell applications using reverse blocking IGBTs

    OpenAIRE

    Klumpner, Christian

    2007-01-01

    Renewable energy sources such as photovoltaics (PVs) or fuel cells (FCs) are not fitted for direct power grid connection because they deliver DC voltage and current. This is why a power electronic interface is needed, consisting usually of a current-mode operated step-up DC/DC converter with/without isolation that boosts the voltage at a level that can be processed by a DC/AC inverter. This paper presents the implementation of a three-phase power electronic interface for PV/FCs that uses a si...

  12. Energy-Recovery Linacs for Commercial Radioisotope Production

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland Paul [Muplus, Inc., Newport News, VA (United States)

    2016-11-19

    Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

  13. REVISS / MAYAK: A new partnership in radioisotope supply

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, N. [REVISS Services Limited, Chesham (United Kingdom); Chikshov, A.I.; Malykh, Y.A. [MAYAK Production Association, Ozyorsk (Russian Federation)

    1997-10-01

    REVISS Services (UK) Limited, the joint venture company formed between Amersham International plc, Production Association MAYAK and Techsnabexport brings together the scientific, manufacturing, marketing and distribution skills and facilities which enable REVISS to be not just a major supplier of radioisotopes and other associated products and services, but the supplier with the largest product range. The paper describes the history and the development of MAYAK and reviews its manufacturing facilities and capabilities and also how MAYAK has moved from being a secret military organisation to become a major and successful commercial organisation

  14. Current source enhancements in Electrical Impedance Spectroscopy (EIS) to cancel unwanted capacitive effects

    OpenAIRE

    Zarafshani, Ali; Bach, Thomas; Chatwin, Chris; Xiang, Liangzhong; Zheng, Bin

    2017-01-01

    Electrical Impedance Spectroscopy (EIS) has emerged as a non-invasive imaging modality to detect and quantify functional or electrical properties related to the suspicious tumors in cancer screening, diagnosis and prognosis assessment. A constraint on EIS systems is that the current excitation system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIS is an ill-posed inverse problem which depends on the noise level in EIS measured data and ...

  15. Impact of the Diamond Light Source on research in Earth and environmental sciences: current work and future perspectives

    OpenAIRE

    I. T. Burke; J. F. W. Mosselmans; S. Shaw; C. L. Peacock; Liane G. Benning; V. S. Coker

    2015-01-01

    Diamond Light Source Ltd celebrated its 10th anniversary as a company in December 2012 and has now accepted user experiments for over 5 years. This paper describes the current facilities available at Diamond and future developments that enhance its capacities with respect to the Earth and environmental sciences. A review of relevant research conducted at Diamond thus far is provided. This highlights how synchrotron-based studies have brought about important advances in our understanding of th...

  16. Generator localization by current source density (CSD): Implications of volume conduction and field closure at intracranial and scalp resolutions

    Science.gov (United States)

    Tenke, Craig E.; Kayser, Jürgen

    2012-01-01

    The topographic ambiguity and reference-dependency that has plagued EEG/ERP research throughout its history are largely attributable to volume conduction, which may be concisely described by a vector form of Ohm’s Law. This biophysical relationship is common to popular algorithms that infer neuronal generators via inverse solutions. It may be further simplified as Poisson’s source equation, which identifies underlying current generators from estimates of the second spatial derivative of the field potential (Laplacian transformation). Intracranial current source density (CSD) studies have dissected the “cortical dipole” into intracortical sources and sinks, corresponding to physiologically-meaningful patterns of neuronal activity at a sublaminar resolution, much of which is locally cancelled (i.e., closed field). By virtue of the macroscopic scale of the scalp-recorded EEG, a surface Laplacian reflects the radial projections of these underlying currents, representing a unique, unambiguous measure of neuronal activity at scalp. Although the surface Laplacian requires minimal assumptions compared to complex, model-sensitive inverses, the resulting waveform topographies faithfully summarize and simplify essential constraints that must be placed on putative generators of a scalp potential topography, even if they arise from deep or partially-closed fields. CSD methods thereby provide a global empirical and biophysical context for generator localization, spanning scales from intracortical to scalp recordings. PMID:22796039

  17. Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

    Science.gov (United States)

    Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

    2017-01-01

    Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

  18. Solid waste as renewable source of energy. Current and future possibility in Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Taqiy Eddine, Boukelia; Salah, Mecibah Med [Mentouri Univ., Constantine (Algeria). Mechanical Dept.

    2012-11-01

    Algeria has created a green momentum by launching an ambitious program to develop renewable energies and promote energy efficiency. Solid waste is one of most important sources of biomass potential in Algeria, which can be used as renewable energy sources. With economic development and the evolution of population, the quantity of solid waste is increasing rapidly in Algeria; according to the National Cadastre for Solid Waste Generation, the overall generation of municipal solid waste was more than 10.3 million tons per year, and the amount of industrial solid waste, including non-hazardous and inert industrial waste was 2,547,000 tons per year, with a stock quantity of 4,483,500 tons. The hazardous waste generated amounts to 325,100 tons per year; the quantities of waste in stock and awaiting a disposal solution amount to 2,008,500 tons. Healthcare waste reaches to 125,000 tons per year. The management of solid waste and its valorization is based on the understanding of solid waste composition by its categories and physicochemical characteristics. Elimination is the solution applied to 97% of waste produced in Algeria. Wastes are disposed in the following ways: open dumps (57%), burned in the open air in public dumps or municipal uncontrolled ones (30%), and controlled dumps and landfill (10%). On the other side, the quantities destined for recovery are too low: only 2% for recycling and 1% for composting. Waste to energy is very attractive option for elimination solid waste with energy recovery. In this paper, we give an overview for this technology, including its conversion options and its useful products (such as electricity, heat and transportation fuel), and waste to energy-related environmental issues and its challenges. (orig.)

  19. Wind energy in Poland – History, current state, surveys, Renewable Energy Sources Act, SWOT analysis

    OpenAIRE

    Iglińska, Anna; Skrzatek, Mateusz; Buczkowski, Roman; Igliński, Bartłomiej; Koziński, Grzegorz Jan

    2016-01-01

    The history, current state and prospects for the development of the wind power sector in Poland have been presented. Poland has a long tradition of using wooden windmills, mainly post mills for economic purposes. Basing on the data of the Institute of Meteorology and Water Management, the speed of wind was calculated in Poland at a height of 100 m. The highest wind speed in Poland is noted in the northern part, the central part and, most of all, in the south-western part. In the December 2015...

  20. GRC Supporting Technology for NASA's Advanced Stirling Radioisotope Generator (ASRG)

    Science.gov (United States)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2008-01-01

    From 1999-2006, the Glenn Research Center (GRC) supported a NASA project to develop a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions. Lockheed Martin was selected as the System Integration Contractor for the SRG110, under contract to the Department of Energy (DOE). The potential applications included deep space missions, and Mars rovers. The project was redirected in 2006 to make use of the Advanced Stirling Convertor (ASC) that was being developed by Sunpower, Inc. under contract to GRC, which would reduce the mass of the generator and increase the power output. This change would approximately double the specific power and result in the Advanced Stirling Radioisotope Generator (ASRG). The SRG110 supporting technology effort at GRC was replanned to support the integration of the Sunpower convertor and the ASRG. This paper describes the ASRG supporting technology effort at GRC and provides details of the contributions in some of the key areas. The GRC tasks include convertor extended-operation testing in air and in thermal vacuum environments, heater head life assessment, materials studies, permanent magnet characterization and aging tests, structural dynamics testing, electromagnetic interference and electromagnetic compatibility characterization, evaluation of organic materials, reliability studies, and analysis to support controller development.

  1. The radioisotope osteogram: Kinetic studies of skeletal disorders in humans

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, N.S.

    1959-10-16

    Radioactive strontium can serve as a tracer to gain information concerning calcium metabolism in human subjects. Gamma-emitting Sr{sup 85} is used rather than the much more hazardous, beta-emitting Sr{sup 89} and Sr{sup 90}. (ca{sup 47} -- the ideal tracer for normal calcium -- is quite expensive and difficult to procure.) Very significant information may be obtained merely by measuring and recording the changes in radioactivity in various body areas during the first hour after intravenous injection of the bone-seeking radioisotope. This is accomplished by placing a lead-shielded gamma-scintillation detector in contact with the skin over the sites of interest and recording the activities on a scaler or ratemeter. The activity versus time curves so obtained are called radioisotope osteograms. Data were presented which indicated that Sr{sup 85} osteograms for patients afflicted with osteoporosis, Paget`s disease, tumor metastases to bone, and possibly multiple myeloma, differ significantly from those obtained from subjects with no skeletal abnormalities. Some interpretations of these deviations were discussed. The value of conducting double-tracer tests (e.g. -- Sr{sup 85} plus radio-iodinated serum albumin) was demonstrated, and correlations with excretion data were made. With further refinements the technique may ultimately become useful for certain diagnostic problems in the clinic and.for evaluating the efficacy of treatment of these disorders.

  2. GEANT4 simulation of cyclotron radioisotope production in a solid target.

    Science.gov (United States)

    Poignant, F; Penfold, S; Asp, J; Takhar, P; Jackson, P

    2016-05-01

    The use of radioisotopes in nuclear medicine is essential for diagnosing and treating cancer. The optimization of their production is a key factor in maximizing the production yield and minimizing the associated costs. An efficient approach to this problem is the use of Monte Carlo simulations prior to experimentation. By predicting isotopes yields, one can study the isotope of interest expected activity for different energy ranges. One can also study the target contamination with other radioisotopes, especially undesired radioisotopes of the wanted chemical element which are difficult to separate from the irradiated target and might result in increasing the dose when delivering the radiopharmaceutical product to the patient. The aim of this work is to build and validate a Monte Carlo simulation platform using the GEANT4 toolkit to model the solid target system of the South Australian Health and Medical Research Institute (SAHMRI) GE Healthcare PETtrace cyclotron. It includes a GEANT4 Graphical User Interface (GUI) where the user can modify simulation parameters such as the energy, shape and current of the proton beam, the target geometry and material, the foil geometry and material and the time of irradiation. The paper describes the simulation and presents a comparison of simulated and experimental/theoretical yields for various nuclear reactions on an enriched nickel 64 target using the GEANT4 physics model QGSP_BIC_AllHP, a model recently developed to evaluate with high precision the interaction of protons with energies below 200MeV available in Geant4 version 10.1. The simulation yield of the (64)Ni(p,n)(64)Cu reaction was found to be 7.67±0.074 mCi·μA(-1) for a target energy range of 9-12MeV. Szelecsenyi et al. (1993) gives a theoretical yield of 6.71mCi·μA(-1) and an experimental yield of 6.38mCi·μA(-1). The (64)Ni(p,n)(64)Cu cross section obtained with the simulation was also verified against the yield predicted from the nuclear database TENDL and

  3. Tannins: current knowledge of food sources, intake, bioavailability and biological effects.

    Science.gov (United States)

    Serrano, José; Puupponen-Pimiä, Riitta; Dauer, Andreas; Aura, Anna-Marja; Saura-Calixto, Fulgencio

    2009-09-01

    Tannins are a unique group of phenolic metabolites with molecular weights between 500 and 30 000 Da, which are widely distributed in almost all plant foods and beverages. Proanthocyanidins and hydrolysable tannins are the two major groups of these bioactive compounds, but complex tannins containing structural elements of both groups and specific tannins in marine brown algae have also been described. Most literature data on food tannins refer only to oligomeric compounds that are extracted with aqueous-organic solvents, but a significant number of non-extractable tannins are usually not mentioned in the literature. The biological effects of tannins usually depend on their grade of polymerisation and solubility. Highly polymerised tannins exhibit low bioaccessibility in the small intestine and low fermentability by colonic microflora. This review summarises a new approach to analysis of extractable and non-extractable tannins, major food sources, and effects of storage and processing on tannin content and bioavailability. Biological properties such as antioxidant, antimicrobial and antiviral effects are also described. In addition, the role of tannins in diabetes mellitus has been discussed.

  4. CURRENT TEACHING SITUATION AND POSSIBILITIES OF OMBROTHERMIC DIAGRAM AS DIGITAL SOURCE

    Directory of Open Access Journals (Sweden)

    Daniel David Martínez Romera

    Full Text Available INTRODUCCIÓN: The main purpose of the present paper is to check how fits Geography technical basis with technological offer available on the Net, having in mind freeware or open source apps only; And, if needed, to design and to build a free digital resource in order to bridge that gap.For us, the starting point is the tradeoff between time spent and scientific accuracy in the classroom. Regardless of the academic level deemed, every teacher is facing this sensitive issue: the longer technical or epistemological questions requires the less contents can be taught. So, in fact, curricular thoroughness tips the balance towards itself, weakening the technical and epistemological aspects. In such context, the specific didactics, such as in the case of Geography, seek new forms of teaching and learning in the ICT world that allows to achive at least: an active role of the students, according to Ausubel, an analytic defiance, in the terms of Vygotsky, and a efficient man-machine interaction, retaking Licklider’s ideas.

  5. Alcoholic fermentation of carbon sources in biomass hydrolysates by Saccharomyces cerevisiae: current status.

    Science.gov (United States)

    van Maris, Antonius J A; Abbott, Derek A; Bellissimi, Eleonora; van den Brink, Joost; Kuyper, Marko; Luttik, Marijke A H; Wisselink, H Wouter; Scheffers, W Alexander; van Dijken, Johannes P; Pronk, Jack T

    2006-11-01

    Fuel ethanol production from plant biomass hydrolysates by Saccharomyces cerevisiae is of great economic and environmental significance. This paper reviews the current status with respect to alcoholic fermentation of the main plant biomass-derived monosaccharides by this yeast. Wild-type S. cerevisiae strains readily ferment glucose, mannose and fructose via the Embden-Meyerhof pathway of glycolysis, while galactose is fermented via the Leloir pathway. Construction of yeast strains that efficiently convert other potentially fermentable substrates in plant biomass hydrolysates into ethanol is a major challenge in metabolic engineering. The most abundant of these compounds is xylose. Recent metabolic and evolutionary engineering studies on S. cerevisiae strains that express a fungal xylose isomerase have enabled the rapid and efficient anaerobic fermentation of this pentose. L: -Arabinose fermentation, based on the expression of a prokaryotic pathway in S. cerevisiae, has also been established, but needs further optimization before it can be considered for industrial implementation. In addition to these already investigated strategies, possible approaches for metabolic engineering of galacturonic acid and rhamnose fermentation by S. cerevisiae are discussed. An emerging and major challenge is to achieve the rapid transition from proof-of-principle experiments under 'academic' conditions (synthetic media, single substrates or simple substrate mixtures, absence of toxic inhibitors) towards efficient conversion of complex industrial substrate mixtures that contain synergistically acting inhibitors.

  6. Effect of double frequency heating on the lead afterglow beam currents of an electron cyclotron resonance ion source

    Science.gov (United States)

    Toivanen, V.; Bellodi, G.; Küchler, D.; Wenander, F.; Tarvainen, O.

    2017-10-01

    The effect of double frequency heating on the performance of the CERN GTS-LHC 14.5 GHz Electron Cyclotron Resonance (ECR) ion source in afterglow mode is reported. The source of the secondary microwave frequency was operated both in pulsed and continuous wave (CW) modes within the range of 12-18 GHz. The results demonstrate that the addition of the secondary frequency can significantly impact the extracted beam currents and the temporal stability of the beam during the afterglow discharge. For example, up to a factor of 2.6 increase was achieved for 208Pb 35 and a factor of 3.1 for 208Pb 37+ compared to single frequency afterglow currents. It is shown that these effects are dependent on the choice of the secondary frequency with respect to the primary one and on the temporal synchronization between the two microwave sources. Overall, the results provide new insight into the afterglow discharge supporting the prevailing understanding of the physical processes behind the phenomenon.

  7. The development of a realistic source term for sodium-cooled fast reactors : assessment of current status and future needs.

    Energy Technology Data Exchange (ETDEWEB)

    LaChance, Jeffrey L.; Phillips, Jesse; Parma, Edward J., Jr.; Olivier, Tara Jean; Middleton, Bobby D.

    2011-06-01

    Sodium-cooled fast reactors (SFRs) continue to be proposed and designed throughout the United States and the world. Although the number of SFRs actually operating has declined substantially since the 1980s, a significant interest in advancing these types of reactor systems remains. Of the many issues associated with the development and deployment of SFRs, one of high regulatory importance is the source term to be used in the siting of the reactor. A substantial amount of modeling and experimental work has been performed over the past four decades on accident analysis, sodium coolant behavior, and radionuclide release for SFRs. The objective of this report is to aid in determining the gaps and issues related to the development of a realistic, mechanistically derived source term for SFRs. This report will allow the reader to become familiar with the severe accident source term concept and gain a broad understanding of the current status of the models and experimental work. Further, this report will allow insight into future work, in terms of both model development and experimental validation, which is necessary in order to develop a realistic source term for SFRs.

  8. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  9. Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

    Energy Technology Data Exchange (ETDEWEB)

    She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

    2016-12-13

    A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

  10. New strategy for eliminating zero-sequence circulating current between parallel operating three-level NPC voltage source inverters

    DEFF Research Database (Denmark)

    Li, Kai; Dong, Zhenhua; Wang, Xiaodong

    2018-01-01

    A novel strategy based on a zero common mode voltage pulse-width modulation (ZCMV-PWM) technique and zero-sequence circulating current (ZSCC) feedback control is proposed in this study to eliminate ZSCCs between three-level neutral point clamped (NPC) voltage source inverters, with common AC and DC...... buses, that are operating in parallel. First, an equivalent model of ZSCC in a three-phase three-level NPC inverter paralleled system is developed. Second, on the basis of the analysis of the excitation source of ZSCCs, i.e., the difference in common mode voltages (CMVs) between paralleled inverters......, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can...

  11. Influence of grid control on beam quality in laser ion source generating high-current low-charged copper ions

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, J.; Yoshida, M.; Ogawa, M.; Oguri, Y.; Nakajima, M.; Horioka, K.; Kwan, J.

    2003-08-01

    We examined grid-controlled extraction for a laser ion source using a KrF laser. By using grid-controlled extraction in the over-dense regime, we found that the ion beam current waveforms were stabilized more significantly as the grid bias raised from -90 V to -280 V. The normalized emittance of 0.08 {pi}mm-mrad measured without the grid control was improved to 0.06 {pi}mm-mrad with the grid control. In contrast to this observation, the grid bias disturbed the pattern of the beam extracted in the source-limited regime. Fast extraction was carried out using a high-voltage pulse with a rise time of {approx} 100 ns. The grid control suppressed successfully the beam pedestal originating from the plasma pre-filled in the extraction gap.

  12. IEA-R1 Nuclear Research Reactor: 58 Years of Operating Experience and Utilization for Research, Teaching and Radioisotopes Production

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, Jose Patricio Nahuel; Filho, Tufic Madi; Saxena, Rajendra; Filho, Walter Ricci [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242 Cid Universitaria CEP: 05508-000- Sao Paulo-SP (Brazil)

    2015-07-01

    IEA-R1 research reactor at the Instituto de Pesquisas Energeticas e Nucleares (Nuclear and Energy Research Institute) IPEN, Sao Paulo, Brazil is the largest power research reactor in Brazil, with a maximum power rating of 5 MWth. It is being used for basic and applied research in the nuclear and neutron related sciences, for the production of radioisotopes for medical and industrial applications, and for providing services of neutron activation analysis, real time neutron radiography, and neutron transmutation doping of silicon. IEA-R1 is a swimming pool reactor, with light water as the coolant and moderator, and graphite and beryllium as reflectors. The reactor was commissioned on September 16, 1957 and achieved its first criticality. It is currently operating at 4.5 MWth with a 60-hour cycle per week. In the early sixties, IPEN produced {sup 131}I, {sup 32}P, {sup 198}Au, {sup 24}Na, {sup 35}S, {sup 51}Cr and labeled compounds for medical use. During the past several years, a concerted effort has been made in order to upgrade the reactor power to 5 MWth through refurbishment and modernization programs. One of the reasons for this decision was to produce {sup 99}Mo at IPEN. The reactor cycle will be gradually increased to 120 hours per week continuous operation. It is anticipated that these programs will assure the safe and sustainable operation of the IEA-R1 reactor for several more years, to produce important primary radioisotopes {sup 99}Mo, {sup 125}I, {sup 131}I, {sup 153}Sm and {sup 192}Ir. Currently, all aspects of dealing with fuel element fabrication, fuel transportation, isotope processing, and spent fuel storage are handled by IPEN at the site. The reactor modernization program is slated for completion by 2015. This paper describes 58 years of operating experience and utilization of the IEA-R1 research reactor for research, teaching and radioisotopes production. (authors)

  13. Hysteresis Current Control of the Single-Phase Voltage Source Inverter Using eMEGAsim Real-Time Simulator

    OpenAIRE

    BOTEZAN, A.; TIRNOVAN, R.; MUNTEANU, R.; GRAUR, A.; RAFIROIU, D.

    2015-01-01

    The paper presents the hysteresis current control of the voltage source inverter. The eMEGAsim real-time simulator is developed by OPAL-RT. Real-time simulation is used in many cases because it allows the behavior of the industrial processes operation to be determined. Two research directions are developed in this case, Rapid Control Prototyping and Hardware-In-the-Loop. Using eMEGAsim simulator allows implementing the command and control strategy of a single-phase voltage sou...

  14. Diagnostics of the cesium amount in an RF negative ion source and the correlation with the extracted current density

    Energy Technology Data Exchange (ETDEWEB)

    Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)]. E-mail: fantz@ipp.mpg.de; Falter, H.D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Franzen, P. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Bandyopadhyay, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Heinemann, B. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Kraus, W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); McNeely, P. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Riedl, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Speth, E. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Tanga, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Wilhelm, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

    2005-11-15

    The formation of negative ions in plasma sources by the surface process requires covering the extraction grid with a material of low work function. This can be achieved by cesium evaporation but for operational reasons the consumption of cesium should be minimised. In order to quantify the amount of cesium in the RF discharge optical emission spectroscopy is used as diagnostic tool. Suitable diagnostic lines and their analysis to obtain particle densities and particle fluxes are described. Influences of argon admixtures to hydrogen and deuterium discharges on cesium emission are shown. A correlation of the cesium emission with the extracted negative ion current density is discussed.

  15. Analysis and design of grid-current-feedback active damping for LCL resonance in grid-connected voltage source converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    in a digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly......This paper investigates the active damping of LCL-filter resonance within single-loop grid current control of grid-connected voltage source converters. First, the basic analysis in the continuous s-domain reveals that the grid-current-feedback active damping forms a virtual impedance across...... the grid-side inductor, and the use of a high-pass filter with a negative sign shapes the virtual impedance by an RL damper paralleled by a negative inductance. It is further found that such a negative virtual inductance plays a critical role in mitigating the phase lag caused by the time delay...

  16. Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2016-01-01

    This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent...... to adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation...... of phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus...

  17. Influence of surface-active bonds of carbon structures on discharge-charging processes of a current source

    Science.gov (United States)

    Kuz'menko, A. P.; Grechushnikov, E. A.; Kharseev, V. A.

    2017-09-01

    A study has been carried out of the effect on the discharge-charging processes of a current source of surface-active bonds of carbon structures used as additives in the composition of a negative electrode material. A mechanism has been proposed based on the conclusions derived from the Kossel-Stranski molecularkinetic theory, which explains the growth of 3PbOPbSO4H2O crystals upon the introduction of carbon materials. It has been established that the presence of carbon additives in the composition of the negative electrode material of starter lead-acid batteries increases the capacitance of 20-h discharge mode by up to 5% and the discharge duration by cold scrolling current to a final voltage of 6 V at negative temperatures of-18°C and-30°C by 3-4.5% and 9-13%, respectively.

  18. Operation and Modulation of H7 Current Source Inverter with Hybrid SiC and Si Semiconductor Switches

    DEFF Research Database (Denmark)

    Wang, Weiqi; Gao, Feng; Yang, Yongheng

    2017-01-01

    This paper proposes an H7 current source inverter (CSI) consisting of a single parallel-connected silicon carbide (SiC) switch and a traditional silicon (Si) H6 CSI. The proposed H7 CSI takes the advantages of the SiC switch to maintain high efficiency, while significantly increasing the switching...... frequency. In order to reduce the switching times and also realize the zero current switching (ZCS) ability for the rear-end CSI, two modulation schemes are proposed for the H7 CSI with either superior output performance or minimal switching counts. Consequently, the proposed H7 CSI can be considered...... as an all-SiC-switch converter in terms of high performance and high efficiency with reduced DC inductance. It provides a cost-effective solution to addressing the efficiency issue of conventional CSI systems. Simulations and experiments are performed to validate the effectiveness of the proposed H7 CSI...

  19. Studies of radioisotope production with an AVF cyclotron in TIARA

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Toshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    The production of radioisotopes to be used mainly for nuclear medicine and biology is studied with an AVF cyclotron in TIARA. A production method of no-carrier-added {sup 186}Re with the {sup 186}W(p,n){sup 186}Re reaction has been developed; this product may be used as a therapeutic agent in radioimmunotherapy due to the adequate nuclear and chemical properties. For the study of the function of plants using a positron-emitter two-dimensional imaging system, a simple method of producing the positron emitter {sup 18}F in water was developed by taking advantage of a highly-energetic {alpha} beam from the AVF cyclotron. (author)

  20. Assessment of myocardial pathogenesis with new radioisotopic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Yamabe, Hiroshi; Yokoyama, Mitsuhiro (Kobe Univ. (Japan). School of Medicine)

    1994-08-01

    In the field of nuclear cardiology, various new radioisotopic tracers have been commercially available since 1993 in Japan. These tracers can be divided into (1) [sup 99m]Tc-labeled myocardial perfusion imaging agents ([sup 99m]Tc-MIBI, [sup 99m]Tc-tetrofosimin, and [sup 99m]Tc-teboroxime); (2) [sup 123]I-labeled myocardial fatty acid imaging agents ([sup 123]-BMIPP and [sup 123]I-IPPA); (3) [sup 123]I-labeled myocardial sympathetic imaging agent ([sup 123]I-MIBG); (4) [sup 111]In-labeled imaging agents for myocardial cell damage ([sup 111]In-monoclonal antimyosin antibody); and (5) [sup 67]Ga thrombosis imaging agent ([sup 67]Ga-fibrinogen). This article outlines these new tracers, focussing on their potential in assessing myocardial pathogenesis. (N.K.) 64 refs.

  1. Radioisotope-Powered Hopper Design for Europan Mission

    Science.gov (United States)

    Dekany, Justin; Guzman, Melissa; Jagadevan, Karthikeyan; McCulley, Jonathan; Shipley, Kevin; Howe, Steven

    2010-10-01

    NASA and ESA have prioritized an outer planet flagship mission to Jupiter and its four largest moons. The constant cycling of material from Europa's surface to the global ocean below allows the potential for organic life similar to the eco-systems surrounding geothermal vents on Earth. The Europa Hopper model utilizes a radioisotope core, in-situ materials and a subsurface ice probe in order to minimize mass and power needs. A hopping distance of 10km was chosen to maximize the surface area coverage of Europa and increasing the potential for organic sampling and geological imaging of Europa's surface. The hopper design has mid-range power and mass needs while maintaining a substantial instrumentation package in comparison to smaller, low-power competitive designs. This mission could provide vital information both on early solar system formation and the potential existence of organic life in the Jovian system.

  2. A 3 A sink/source current fast transient response low-dropout G{sub m} driven linear regulator

    Energy Technology Data Exchange (ETDEWEB)

    Chu Xiuqin; Li Qingwei; Lai Xinquan; Yuan Bing [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China); Li Yanming [School of Electronic and Control Engineering, Chang' an University, Xi' an 710064 (China); Zhao Yongrui, E-mail: liqw309@163.com, E-mail: xqchu@mail.xidian.edu.cn [Key Laboratory of High-Speed Circuit Design and EMC, Ministry of Education, Xidian University, Xi' an 710071 (China)

    2011-06-15

    A 3 A sink/source G{sub m}-driven CMOS low-dropout regulator (LDO), specially designed for low input voltage and low cost, is presented by utilizing the structure of a current mirror G{sub m} (transconductance) driving technique, which provides high stability as well as a fast load transient response. The proposed LDO was fabricated by a 0.5 {mu}m standard CMOS process, and the die size is as small as 1.0 mm{sup 2}. The proposed LDO dissipates 220 {mu}A of quiescent current in no-load conditions and is able to deliver up to 3 A of load current. The measured results show that the output voltage can be resumed within 2 {mu}s with a less than 1 mV overshoot and undershoot in the output current step from -1.8 to 1.8 A with a 0.1 {mu}s rising and falling time at three 10 {mu}F ceramic capacitors. (semiconductor integrated circuits)

  3. Sources

    OpenAIRE

    2015-01-01

    Sources Fondation Pablo Iglesias. Alcala de Henares. Sections : Archives privées de Manuel ArijaArchives extérieuresArchives FNJS de EspañaPrensa Archives Générales de l’Administration. Alcala de Henares. Sections : Opposition au franquismeSig. 653 Sig TOP 82/68.103-68.602.Índice de las cartas colectivas, Relaciones, Cartas al Ministro de Información de Marzo de 1965. c.662. Sources cinématographiques Filmothèque Nationale d’Espagne.NO.DO. N° 1157C. 08/03/1965.aguirre Javier, Blanco vertical....

  4. The Mars Hopper: a radioisotope powered, impulse driven, long-range, long-lived mobile platform for exploration of Mars

    Energy Technology Data Exchange (ETDEWEB)

    Steven D. Howe; Robert C. O' Brien; William Taitano; Doug Crawford; Nathan Jerred; Spencer Cooley; John Crapeau; Steve Hansen; Andrew Klein; James Werner

    2011-02-01

    Planetary exploration mission requirements are becoming more demanding. Due to the increasing cost, the missions that provide mobile platforms that can acquire data at multiple locations are becoming more attractive. Wheeled vehicles such as the MER rovers have proven extremely capable but have very limited range and cannot traverse rugged terrain. Flying vehicles such as balloons and airplanes have been proposed but are problematic due to the very thin atmospheric pressure and the strong, dusty winds present on Mars. The Center for Space Nuclear Research has designed an instrumented platform that can acquire detailed data at hundreds of locations during its lifetime - a Mars Hopper. The Mars Hopper concept utilizes energy from radioisotopic decay in a manner different from any existing radioisotopic power sources—as a thermal capacitor. By accumulating the heat from radioisotopic decay for long periods, the power of the source can be dramatically increased for short periods. The platform will be able to "hop" from one location to the next every 5-7 days with a separation of 5-10 km per hop. Preliminary designs show a platform that weighs around 52 kgs unfueled which is the condition at deployment. Consequently, several platforms may be deployed on a single launch from Earth. With sufficient lifetime, the entire surface of Mars can be mapped in detail by a couple dozen platforms. In addition, Hoppers can collect samples from all over the planet, including gorges, mountains and crevasses, and deliver them to a central location for eventual pick-up by a Mars Sample Return mission. The status of the Mars Hopper development project at the CSNR is discussed.

  5. Advanced Stirling Convertor Development for NASA Radioisotope Power Systems

    Science.gov (United States)

    Wong, Wayne A.; Wilson, Scott D.; Collins, Josh

    2015-01-01

    Sunpower Inc.'s Advanced Stirling Convertor (ASC) initiated development under contract to the NASA Glenn Research Center and after a series of successful demonstrations, the ASC began transitioning from a technology development project to a flight development project. The ASC has very high power conversion efficiency making it attractive for future Radioisotope Power Systems (RPS) in order to make best use of the low plutonium-238 fuel inventory in the United States. In recent years, the ASC became part of the NASA and Department of Energy (DOE) Advanced Stirling Radioisotope Generator (ASRG) Integrated Project. Sunpower held two parallel contracts to produce ASCs, one with the DOE and Lockheed Martin to produce the ASC-F flight convertors, and one with NASA Glenn for the production of ASC-E3 engineering units, the initial units of which served as production pathfinders. The integrated ASC technical team successfully overcame various technical challenges that led to the completion and delivery of the first two pairs of flightlike ASC-E3 by 2013. However, in late fall 2013, the DOE initiated termination of the Lockheed Martin ASRG flight development contract driven primarily by budget constraints. NASA continues to recognize the importance of high-efficiency ASC power conversion for RPS and continues investment in the technology including the continuation of ASC-E3 production at Sunpower and the assembly of the ASRG Engineering Unit #2. This paper provides a summary of ASC technical accomplishments, overview of tests at Glenn, plans for continued ASC production at Sunpower, and status of Stirling technology development.

  6. Dose calibrator linearity test: 99mTc versus 18F radioisotopes*

    Science.gov (United States)

    Willegaignon, José; Sapienza, Marcelo Tatit; Coura-Filho, George Barberio; Garcez, Alexandre Teles; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga; Buchpiguel, Carlos Alberto

    2015-01-01

    Objective The present study was aimed at evaluating the viability of replacing 18F with 99mTc in dose calibrator linearity testing. Materials and Methods The test was performed with sources of 99mTc (62 GBq) and 18F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical 99mTc and 18F sources activities were calculated and subsequently compared. Results Mean deviations between experimental and theoretical 99mTc and 18F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the 99mTc source as measured with the equipment pre-calibrated to measure 99mTc and 18F was 3.42 (± 0.06), and for the 18F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion The results of the linearity test using 99mTc were compatible with those obtained with the 18F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in 18F acquisition suggest 99mTc as the element of choice to perform dose calibrator linearity tests in centers that use 18F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. PMID:25798005

  7. Dose calibrator linearity test: {sup 99m}Tc versus {sup 18}F radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Willegaignon, Jose; Coura-Filho, George Barberio; Garcez, Alexandre Teles, E-mail: willegaignon@hotmail.com [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil); Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Fac. de Medicina; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2015-01-15

    Objective: the present study was aimed at evaluating the viability of replacing {sup 18}F with {sup 99m}Tc in dose calibrator linearity testing. Materials and methods: the test was performed with sources of {sup 99m}Tc (62 GBq) and {sup 18}F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were calculated and subsequently compared. Results: mean deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the {sup 99m}Tc source as measured with the equipment precalibrated to measure {sup 99m}Tc and {sup 18}F was 3.42 (± 0.06), and for the {sup 18}F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion: the results of the linearity test using {sup 99m}Tc were compatible with those obtained with the {sup 18}F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in {sup 18}F acquisition suggest {sup 99m}Tc as the element of choice to perform dose calibrator linearity tests in centers that use {sup 18}F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. (author)

  8. Novel design of high voltage pulse source for efficient dielectric barrier discharge generation by using silicon diodes for alternating current.

    Science.gov (United States)

    Truong, Hoa Thi; Hayashi, Misaki; Uesugi, Yoshihiko; Tanaka, Yasunori; Ishijima, Tatsuo

    2017-06-01

    This work focuses on design, construction, and optimization of configuration of a novel high voltage pulse power source for large-scale dielectric barrier discharge (DBD) generation. The pulses were generated by using the high-speed switching characteristic of an inexpensive device called silicon diodes for alternating current and the self-terminated characteristic of DBD. The operation started to be powered by a primary DC low voltage power supply flexibly equipped with a commercial DC power supply, or a battery, or DC output of an independent photovoltaic system without transformer employment. This flexible connection to different types of primary power supply could provide a promising solution for the application of DBD, especially in the area without power grid connection. The simple modular structure, non-control requirement, transformer elimination, and a minimum number of levels in voltage conversion could lead to a reduction in size, weight, simple maintenance, low cost of installation, and high scalability of a DBD generator. The performance of this pulse source has been validated by a load of resistor. A good agreement between theoretically estimated and experimentally measured responses has been achieved. The pulse source has also been successfully applied for an efficient DBD plasma generation.

  9. Novel design of high voltage pulse source for efficient dielectric barrier discharge generation by using silicon diodes for alternating current

    Science.gov (United States)

    Truong, Hoa Thi; Hayashi, Misaki; Uesugi, Yoshihiko; Tanaka, Yasunori; Ishijima, Tatsuo

    2017-06-01

    This work focuses on design, construction, and optimization of configuration of a novel high voltage pulse power source for large-scale dielectric barrier discharge (DBD) generation. The pulses were generated by using the high-speed switching characteristic of an inexpensive device called silicon diodes for alternating current and the self-terminated characteristic of DBD. The operation started to be powered by a primary DC low voltage power supply flexibly equipped with a commercial DC power supply, or a battery, or DC output of an independent photovoltaic system without transformer employment. This flexible connection to different types of primary power supply could provide a promising solution for the application of DBD, especially in the area without power grid connection. The simple modular structure, non-control requirement, transformer elimination, and a minimum number of levels in voltage conversion could lead to a reduction in size, weight, simple maintenance, low cost of installation, and high scalability of a DBD generator. The performance of this pulse source has been validated by a load of resistor. A good agreement between theoretically estimated and experimentally measured responses has been achieved. The pulse source has also been successfully applied for an efficient DBD plasma generation.

  10. Deuteron nuclear data for the design of accelerator-based neutron sources: Measurement, model analysis, evaluation, and application

    Science.gov (United States)

    Watanabe, Yukinobu; Kin, Tadahiro; Araki, Shouhei; Nakayama, Shinsuke; Iwamoto, Osamu

    2017-09-01

    A comprehensive research program on deuteron nuclear data motivated by development of accelerator-based neutron sources is being executed. It is composed of measurements of neutron and gamma-ray yields and production cross sections, modelling of deuteron-induced reactions and code development, nuclear data evaluation and benchmark test, and its application to medical radioisotopes production. The goal of this program is to develop a state-of-the-art deuteron nuclear data library up to 200 MeV which will be useful for the design of future (d,xn) neutron sources. The current status and future plan are reviewed.

  11. Study of radioisotope safety devices for electric propulsion system, Volume 1: Summary report

    Science.gov (United States)

    Bradshaw, G. B.; Homeyer, W. G.; Postula, F. D.; Steeger, E. J.

    1972-01-01

    A new reference design was prepared for the 5 kW(e) thermionic power supply. The safety equipment in this design is a passive containment system which does not rely on the operation of any mechanisms such as a launch escape rocket or deployment of parachutes. It includes: (1) a blast shield to protect against the explosion of the launch vehicle; (2) a combination of refractory thermal insulation and heat storage material to protect against a sustained launch pad fire; (3) a reentry body with a spherical nose and a large conical flare at the aft end to stabilize the reentry attitude and lower the terminal velocity in air; (4) composite graphite thermal protection to sustain the reentry heat pulse; (5) crushable honeycomb behind the nose to limit the deceleration of the radioisotope source due to impact on land at terminal velocity; (6) a double-walled secondary containment vessel surrounding the isotopic capsules; (7) neutron shielding to reduce external dose rates; (8) an auxiliary cooling system employing redundant heat pipes to remove the radioactive decay heat from the heat source and reject it to the surroundings or to a forced convection loop.

  12. Deep-Ocean Crusts as Telescopes: Using Live Radioisotopes to Probe Supernova Nucleosynthesis

    CERN Document Server

    Fields, B D; Ellis, Jonathan Richard; Fields, Brian D.; Hochmuth, Kathrin A.; Ellis, John

    2005-01-01

    Live 60Fe has recently been detected in a deep-ocean ferromanganese crust, isolated in layers dating from about 3 Myr ago. Since 60Fe has a mean life of 2.2 Myr, a near-Earth supernova is the only likely source for such a signal, and we explore here the consequences of a supernova origin. We combine the 60Fe data with several supernova nucleosynthesis models to calculate the supernova distance as a function of progenitor mass, finding an allowed range of 15-120 pc. We also predict the signals expected for several other radioisotopes, which are independent of the supernova distance. Species likely to be present near or above background levels are 10Be, 26Al, 53Mn, 182Hf and 244Pu. Of these, 182Hf and 244Pu are nearly background-free, presenting the best opportunities to provide strong confirmation of the supernova origin of the 60Fe signal, and to demonstrate that at least some supernovae are the source for the r-process. The accuracies of our predictions are hampered by large uncertainties in the predicted 60...

  13. Impact of the Diamond Light Source on research in Earth and environmental sciences: current work and future perspectives

    Science.gov (United States)

    Burke, Ian T.; Mosselmans, J. Frederick W.; Shaw, Samuel; Peacock, Caroline L.; Benning, Liane G.; Coker, Victoria S.

    2015-01-01

    Diamond Light Source Ltd celebrated its 10th anniversary as a company in December 2012 and has now accepted user experiments for over 5 years. This paper describes the current facilities available at Diamond and future developments that enhance its capacities with respect to the Earth and environmental sciences. A review of relevant research conducted at Diamond thus far is provided. This highlights how synchrotron-based studies have brought about important advances in our understanding of the fundamental parameters controlling highly complex mineral–fluid–microbe interface reactions in the natural environment. This new knowledge not only enhances our understanding of global biogeochemical processes, but also provides the opportunity for interventions to be designed for environmental remediation and beneficial use. PMID:25624516

  14. Impact of the Diamond Light Source on research in Earth and environmental sciences: current work and future perspectives.

    Science.gov (United States)

    Burke, Ian T; Mosselmans, J Frederick W; Shaw, Samuel; Peacock, Caroline L; Benning, Liane G; Coker, Victoria S

    2015-03-06

    Diamond Light Source Ltd celebrated its 10th anniversary as a company in December 2012 and has now accepted user experiments for over 5 years. This paper describes the current facilities available at Diamond and future developments that enhance its capacities with respect to the Earth and environmental sciences. A review of relevant research conducted at Diamond thus far is provided. This highlights how synchrotron-based studies have brought about important advances in our understanding of the fundamental parameters controlling highly complex mineral-fluid-microbe interface reactions in the natural environment. This new knowledge not only enhances our understanding of global biogeochemical processes, but also provides the opportunity for interventions to be designed for environmental remediation and beneficial use.

  15. Desain dan Implementasi Current-Controlled Voltage Source Inverter untuk Kontrol Tegangan dan Frekuensi Generator Induksi Tiga Fasa

    Directory of Open Access Journals (Sweden)

    Resa Hidayat Pramasdeka

    2017-03-01

    Full Text Available Mesin induksi dapat menghasilkan daya saat kecepatannya di atas kecepatan sinkron, bisa disebut juga sebagai generator induksi. Mesin induksi memiliki kelebihan yaitu konstruksinya yang simpel, level short-circuit yang rendah, perawatan yang mudah, dan harganya lebih murah. Dari semua kelebihan tersebut, mesin induksi juga memiliki kekurangan saat difungsikan sebagai generator yaitu karakteristik regulasi tegangan dan frekuensi yang tidak memuaskan serta membutuhkan daya reaktif untuk menjaga eksitasi. Perlu diketahui bahwa generator induksi tidak menghasilkan daya reaktif, tetapi membutuhkan daya reaktif dari luar. Untuk mengatasi masalah di atas, digunakanlah elektronika daya dengan menerapkan metode Current-Controlled pada Voltage Source Inverter (CC-VSI sebagai pengontrol tegangan dan frekuensi output dari generator serta menyediakan daya reaktif untuk beban pada sisi AC. Sistem tersebut diperoleh dengan memberikan sinyal Sinusoidal Pulse Width Modulation (SPWM ke IGBT/MOSFET pada inverter untuk pensaklaran. Dengan adanya CC-VSI, eksitasi yang dibutuhkan mesin dapat terpenuhi serta frekuensi, tegangan, dan aliran daya dapat dikontrol.

  16. Technical Reviews on the Petroleum Refining Industry and the Petrochemical Industry for the Development of Industrial Application of Radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung-Hee; Kim, Jong-Bum; Lee, Na-Young; Kwon, Taek-Yong

    2008-09-15

    Petroleum is the major energy source that supplies 35% of the total power all over the world. And the petrochemical industry generates a 120 times higher value from naphtha, and in cooperates new technology in order to keep its business prosperous. These large plant industries require in-service diagnosis technology for an optimal and efficient operation and maintenance. Since diagnosis information obtained from an on-line plant can be used for a correct operation and maintenance workplan in the case of a deteriorated product quality as well as a mechanical abnormality, this technology can contribute to a huge cost benefit and a product competitiveness. The gigantic plants equipped with heavy materials can hardly be evaluated with conventional techniques due to their harsh environment of a high temperature and a pressure. Radiation and radioisotope application technology has been studied to meet the demand of the industry, but has yet to be developed further. In spite of its usefulness, the strategic support is not enough to carry out the research activities on advanced industrial testing technology using radioisotopes. It is of importance to secure a national competitiveness by intensifying the support for the newly emerging technologies such as an industrial gamma tomography and a process visualization and validation incorporated with a CFD.

  17. Wind Farm Stabilization by using DFIG with Current Controlled Voltage Source Converters Taking Grid Codes into Consideration

    Science.gov (United States)

    Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

    Recent wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage is recovered. However, fixed speed wind turbine generator system using induction generator (IG) has the stability problem similar to the step-out phenomenon of a synchronous generator. On the other hand, doubly fed induction generator (DFIG) can control its real and reactive powers independently while being operated in variable speed mode. This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs, without incorporating additional FACTS devices. A new current controlled voltage source converter (CC-VSC) scheme is proposed to control the converters of DFIG and the performance is verified by comparing the results with those of voltage controlled voltage source converter (VC-VSC) scheme. Another salient feature of this study is to reduce the number of proportionate integral (PI) controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme during grid fault can be omitted in the proposed scheme which reduces overall cost of the system. Extensive simulation analyses by using PSCAD/EMTDC are carried out to clarify the effectiveness of the proposed CC-VSC based control scheme of DFIGs.

  18. Long Life 600W Hall Thruster System for Radioisotope Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radioisotope Electric Propulsion (REP) offers the prospect for a variety of new science missions by enabling use of Hall Effect propulsion in the outer solar system,...

  19. Iron Oxide Nanoradiomaterials: Combining Nanoscale Properties with Radioisotopes for Enhanced Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Juan Pellico

    2017-01-01

    Full Text Available The combination of the size-dependent properties of nanomaterials with radioisotopes is emerging as a novel tool for molecular imaging. There are numerous examples already showing how the controlled synthesis of nanoparticles and the incorporation of a radioisotope in the nanostructure offer new features beyond the simple addition of different components. Among the different nanomaterials, iron oxide-based nanoparticles are the most used in imaging because of their versatility. In this review, we will study the different radioisotopes for biomedical imaging, how to incorporate them within the nanoparticles, and what applications they can be used for. Our focus is directed towards what is new in this field, what the nanoparticles can offer to the field of nuclear imaging, and the radioisotopes hybridized with nanomaterials for use in molecular imaging.

  20. Sources

    OpenAIRE

    2014-01-01

    Archives Archivo Histórico del Estado de Jalisco Fondo Gobernación, Asunto Pasaportes y Salvoconductos : G-8-877/9773-9775 G-8-878/9774, 9776, 9777 et 9781 G-8-879/9782-9788 G-8-880/9789-9798 G-8-881-882/9803 G-8-882/9804-9805 G-8-883/9806-9811 G-8-884/9813 G-8-885/9817-9820 G-8-886/9822-9825 G-8-887/9826-9830 G-8-888/9835 G-8-889-890/9837 G-8-889/9839 Sources imprimées Livres et chroniques O’Farrill Romulo, (2004) Reseña histórica estadística y comercial de México y sus estados, directorio g...

  1. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health.

    Science.gov (United States)

    Stephen, Alison M; Champ, Martine M-J; Cloran, Susan J; Fleith, Mathilde; van Lieshout, Lilou; Mejborn, Heddie; Burley, Victoria J

    2017-12-01

    Research into the analysis, physical properties and health effects of dietary fibre has continued steadily over the last 40-50 years. From the knowledge gained, countries have developed guidelines for their populations on the optimal amount of fibre to be consumed each day. Food composition tables from many countries now contain values for the dietary fibre content of foods, and, from these, combined with dietary surveys, population intakes have been determined. The present review assessed the uniformity of the analytical methods used, health claims permitted, recommendations and intakes, particularly from national surveys across Europe and around the world. It also assessed current knowledge on health effects of dietary fibre and related the impact of different fibre types on health. The overall intent was to be able to provide more detailed guidance on the types of fibre which should be consumed for good health, rather than simply a total intake figure, the current situation. Analysis of data indicated a fair degree of uniformity in the definition of dietary fibre, the method used for analysis, the recommended amount to be consumed and a growing literature on effects on digestive health and disease risk. However, national dietary survey data showed that intakes do not reach recommendations and very few countries provide guidance on the types of fibre that are preferable to achieve recommended intakes. Research gaps were identified and ideas suggested to provide information for more detailed advice to the public about specific food sources that should be consumed to achieve health benefits.

  2. Sustained attention in skilled and novice martial arts athletes: a study of event-related potentials and current sources.

    Science.gov (United States)

    Sanchez-Lopez, Javier; Silva-Pereyra, Juan; Fernandez, Thalia

    2016-01-01

    Background. Research on sports has revealed that behavioral responses and event-related brain potentials (ERP) are better in expert than in novice athletes for sport-related tasks. Focused attention is essential for optimal athletic performance across different sports but mainly in combat disciplines. During combat, long periods of focused attention (i.e., sustained attention) are required for a good performance. Few investigations have reported effects of expertise on brain electrical activity and its neural generators during sport-unrelated attention tasks. The aim of the present study was to assess the effect of expertise (i.e., skilled and novice martial arts athletes) analyzing the ERP during a sustained attention task (Continuous Performance Task; CPT) and the cortical three-dimensional distribution of current density, using the sLORETA technique. Methods. CPT consisted in an oddball-type paradigm presentation of five stimuli (different pointing arrows) where only one of them (an arrow pointing up right) required a motor response (i.e., target). CPT was administered to skilled and novice martial arts athletes while EEG were recorded. Amplitude ERP data from target and non-target stimuli were compared between groups. Subsequently, current source analysis for each ERP component was performed on each subject. sLORETA images were compared by condition and group using Statistical Non-Parametric Mapping analysis. Results. Skilled athletes showed significant amplitude differences between target and non-target conditions in early ERP components (P100 and P200) as opposed to the novice group; however, skilled athletes showed no significant effect of condition in N200 but novices did show a significant effect. Current source analysis showed greater differences in activations in skilled compared with novice athletes between conditions in the frontal (mainly in the Superior Frontal Gyrus and Medial Frontal Gyrus) and limbic (mainly in the Anterior Cingulate Gyrus) lobes

  3. Sustained attention in skilled and novice martial arts athletes: a study of event-related potentials and current sources

    Directory of Open Access Journals (Sweden)

    Javier Sanchez-Lopez

    2016-01-01

    Full Text Available Background. Research on sports has revealed that behavioral responses and event-related brain potentials (ERP are better in expert than in novice athletes for sport-related tasks. Focused attention is essential for optimal athletic performance across different sports but mainly in combat disciplines. During combat, long periods of focused attention (i.e., sustained attention are required for a good performance. Few investigations have reported effects of expertise on brain electrical activity and its neural generators during sport-unrelated attention tasks. The aim of the present study was to assess the effect of expertise (i.e., skilled and novice martial arts athletes analyzing the ERP during a sustained attention task (Continuous Performance Task; CPT and the cortical three-dimensional distribution of current density, using the sLORETA technique. Methods. CPT consisted in an oddball-type paradigm presentation of five stimuli (different pointing arrows where only one of them (an arrow pointing up right required a motor response (i.e., target. CPT was administered to skilled and novice martial arts athletes while EEG were recorded. Amplitude ERP data from target and non-target stimuli were compared between groups. Subsequently, current source analysis for each ERP component was performed on each subject. sLORETA images were compared by condition and group using Statistical Non-Parametric Mapping analysis. Results. Skilled athletes showed significant amplitude differences between target and non-target conditions in early ERP components (P100 and P200 as opposed to the novice group; however, skilled athletes showed no significant effect of condition in N200 but novices did show a significant effect. Current source analysis showed greater differences in activations in skilled compared with novice athletes between conditions in the frontal (mainly in the Superior Frontal Gyrus and Medial Frontal Gyrus and limbic (mainly in the Anterior Cingulate

  4. Clouds, airplanes, trucks and people : carrying radioisotopes to and across Mexico

    OpenAIRE

    Mateos, Gisela

    2015-01-01

    The aim of this paper is to describe the early stages of Mexican nuclearization that took place in contact with radioisotopes. This history requires a multilayered narrative with an emphasis in North-South asymmetric relations, and in the value of education and training in the creation of international asymmetrical networks. Radioisotopes were involved in exchanges with the United States since the late 1940s, but also with Canada. We also describe the context of implementation of Eisenhower´s...

  5. Investigation of key factors in preparation of alpha sources by electrodeposition.

    Science.gov (United States)

    Krmpotić, Matea; Rožmarić, Martina; Benedik, Ljudmila

    2018-02-09

    The electrodeposition for alpha source preparation, using several electrolyte solution-cathode material combinations, is investigated and evaluated. The investigated factors focused on the electrodeposition time, the applied current, electrolyte volume and anode-cathode distances for the conventional electrodeposition cell (with no external stirring or cooling system). The conditions (temperature and the solution pH) during the electrodeposition process were also studied and discussed. The optimized parameters for each system are provided, and evaluated for the usage in determination of actinides (uranium, plutonium, americium and curium radioisotopes) in various samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Sediment source fingerprinting as an aid to catchment management: A review of the current state of knowledge and a methodological decision-tree for end-users

    Science.gov (United States)

    Collins, A.L; Pulley, S.; Foster, I.D.L; Gellis, Allen; Porto, P.; Horowitz, A.J.

    2017-01-01

    The growing awareness of the environmental significance of fine-grained sediment fluxes through catchment systems continues to underscore the need for reliable information on the principal sources of this material. Source estimates are difficult to obtain using traditional monitoring techniques, but sediment source fingerprinting or tracing procedures, have emerged as a potentially valuable alternative. Despite the rapidly increasing numbers of studies reporting the use of sediment source fingerprinting, several key challenges and uncertainties continue to hamper consensus among the international scientific community on key components of the existing methodological procedures. Accordingly, this contribution reviews and presents recent developments for several key aspects of fingerprinting, namely: sediment source classification, catchment source and target sediment sampling, tracer selection, grain size issues, tracer conservatism, source apportionment modelling, and assessment of source predictions using artificial mixtures. Finally, a decision-tree representing the current state of knowledge is presented, to guide end-users in applying the fingerprinting approach.

  7. Theoretical dosimetry estimations for radioisotopes produced by proton-induced reactions on natural and enriched molybdenum targets

    Science.gov (United States)

    Hou, X.; Celler, A.; Grimes, J.; Bénard, F.; Ruth, T.

    2012-03-01

    This study presents a summary of the dosimetry calculations performed for three technetium agents most commonly used in nuclear medicine diagnostic studies, namely sestamibi™, phosphonates and pertechnetate, labeled with cyclotron-produced technetium. Calculated patient doses were compared to those that would be delivered by the same radiotracers labeled with technetium obtained from a generator produced in a reactor. The main difference is that technetium from a generator is pure, i.e. contains only 99mTc and its decay product 99gTc, while in a cyclotron a large number of other stable and radioactive isotopes are created. In our calculations only technetium radioisotopes (ground and isomeric states) were considered as they will be included in the radiotracer labeling process and will contribute to the patient dose. Other elements should be removed by chemical purification. These dose estimates are based on our theoretical calculations of the proton-induced reaction cross sections and radioisotope production yields. Thick targets of enriched (three different compositions) and natural molybdenum, and three initial beam energies (16, 19 and 24 MeV) were considered for irradiation times of 3, 6 and 12 h with a beam current of 200 µA. The doses were calculated for injection times corresponding to 0, 2, 8, 12 and 24 h after the end of beam.

  8. Radioisotope Power Systems Reference Book for Mission Designers and Planners

    Science.gov (United States)

    Lee, Young; Bairstow, Brian

    2015-01-01

    The RPS Program's Program Planning and Assessment (PPA) Office commissioned the Mission Analysis team to develop the Radioisotope Power Systems (RPS) Reference Book for Mission Planners and Designers to define a baseline of RPS technology capabilities with specific emphasis on performance parameters and technology readiness. The main objective of this book is to provide RPS technology information that could be utilized by future mission concept studies and concurrent engineering practices. A progress summary from the major branches of RPS technology research provides mission analysis teams with a vital tool for assessing the RPS trade space, and provides concurrent engineering centers with a consistent set of guidelines for RPS performance characteristics. This book will be iterated when substantial new information becomes available to ensure continued relevance, serving as one of the cornerstone products of the RPS PPA Office. This book updates the original 2011 internal document, using data from the relevant publicly released RPS technology references and consultations with RPS technologists. Each performance parameter and RPS product subsection has been reviewed and cleared by at least one subject matter representative. A virtual workshop was held to reach consensus on the scope and contents of the book, and the definitions and assumptions that should be used. The subject matter experts then reviewed and updated the appropriate sections of the book. The RPS Mission Analysis Team then performed further updates and crosschecked the book for consistency. Finally, a second virtual workshop was held to ensure all subject matter experts and stakeholders concurred on the contents.

  9. Development of radioisotope tracer technology and nucleonic control system

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee and others

    1999-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and basic technology of nuclear control systems that are widely used for automation of industrial plants, and to build a strong tracer group to support the local industries. In relation to the tracer technology, the data acquisition system, the column scanning equipment and the detection pig for a leakage test have been developed. In order to use in analyzing data of tracer experiments, a computer program for the analysis of residence time distribution has been created as well. These results were utilized in developing the tracer technologies, such as the column scanning, the flow measurement using the dilution method, the simultaneous monitoring rotational movement of piston rings and the optimization of a waste water treatment facility, and the technologies were successfully demonstrated in the local industrial. The stripper of RFCC reactor has been examined to find an unwanted structure in it by imminent request from the industry. Related to the development of nucleonic control system, the state of art report on the technology has been written and an equipment for the analysis of asphalt content has been developed. (author)

  10. Cascaded Thermoelectric Conversion-Advanced Radioisotope Power Systems (CTC-ARPSs)

    Science.gov (United States)

    El-Genk, Mohamed S.; Saber, Hamed H.

    2004-02-01

    Conceptual designs of Advanced Radioisotope Power System (ARPS) with Cascaded Thermoelectric Converters (CTCs) are developed and optimized for maximum efficiency operation for End-Of Mission (EOM) electrical power of at least 100 We. These power systems each employs four General Purpose Heat Source (GPHS) bricks generating 1000 Wth at Beginning-of-Life (BOL) and 32 Cascaded Thermoelectric Modules (CTMs). Each CTM consists of a top and a bottom array of thermoelectric unicouples, which are thermally, but not electrically, coupled. The top and bottom arrays of the CTMs are connected electrically in series in two parallel strings with the same nominal voltage of > 28 VDC. The SiGe unicouples in the top array of the CTMs are optimized for nominal hot shoe temperature of 1273 K and constant cold shoe temperature of either 780 K or 980 K, depending on the thermoelectric materials of the unicouples in the bottom array. For a SiGe cold junction temperature of 780 K, the unicouples in the bottom array have p-legs of TAGS-85 and n-legs of 2N-PbTe and operate at constant hot junction temperature of 765 K and nominal cold junction temperature of 476.4 K. When the SiGe cold junction temperature is 980 K, the unicouples in the bottom arrays of CTMs have p-legs of CeFe3.5Co0.5Sb12 or CeFe3.5Co0.5Sb12 and Zn4Sb3, segments and n-legs of CoSb3 and operate at constant hot junction temperature of 965 K and nominal cold junction temperatures of 446.5 K or 493.5 K, respectively. The CTC-ARPSs have a nominal efficiency of 10.82% - 10.85% and generate BOL power of 108 We. This system efficiency is ~ 80% higher than that of State-of-the-Art (SOA) Radioisotope Thermoelectric Generators (RTGs), requiring 7 GHPS bricks and generating 105 We at BOL. The CTC-ARPSs have specific powers of 8.2 We/kg to 8.8 We/kg, which are 71% to 83% higher, respectively, than that of the SOA-RTGs, and use ~ 43% less 238PuO2 fuel.

  11. Detection and tracing of the medical radioisotope 131I in the Canberra environment

    Science.gov (United States)

    Gilfillan, Nathan R.; Timmers, Heiko

    2012-10-01

    The transport and radioecology of the therapeutical radioisotope 131I has been studied in Canberra, Australia. The isotope has been detected in water samples and its activity quantified via characteristic J-ray photo peaks. A comparison of measurements on samples from upstream and downstream of the Canberra waste water treatment plant shows that 131I is discharged from the plant outflow into the local Molonglo river. This is consistent with observations in other urban environments. A time-correlation between the measured activities in the outflow and the therapeutical treatment cycle at the hospital identifies the medical treatment as the source of the isotope. Enhanced activity levels of 131I have been measured for fish samples. This may permit conclusions on 131I uptake by the biosphere. Due to the well-defined and intermittent input of 131I into the sewage, the Canberra situation is ideally suited for radioecological studies. Furthermore, the 131I activity may be applied in tracer studies of sewage transport to and through the treatment plant and as an indicator of outflow dilution following discharge to the environment.

  12. Radioisotope Stirling Engine Powered Airship for Atmospheric and Surface Exploration of Titan

    Science.gov (United States)

    Colozza, Anthony J.; Cataldo, Robert L.

    2014-01-01

    The feasibility of an advanced Stirling radioisotope generator (ASRG) powered airship for the near surface exploration of Titan was evaluated. The analysis did not consider the complete mission only the operation of the airship within the atmosphere of Titan. The baseline airship utilized two ASRG systems with a total of four general-purpose heat source (GPHS) blocks. Hydrogen gas was used to provide lift. The ASRG systems, airship electronics and controls and the science payload were contained in a payload enclosure. This enclosure was separated into two sections, one for the ASRG systems and the other for the electronics and payload. Each section operated at atmospheric pressure but at different temperatures. The propulsion system consisted of an electric motor driving a propeller. An analysis was set up to size the airship that could operate near the surface of Titan based on the available power from the ASRGs. The atmospheric conditions on Titan were modeled and used in the analysis. The analysis was an iterative process between sizing the airship to carry a specified payload and the power required to operate the electronics, payload and cooling system as well as provide power to the propulsion system to overcome the drag on the airship. A baseline configuration was determined that could meet the power requirements and operate near the Titan surface. From this baseline design additional trades were made to see how other factors affected the design such as the flight altitude and payload mass and volume.

  13. Radioisotope tracer studies of inorganic carbon and Ca in microbially derived CaCO3

    Science.gov (United States)

    Yates, Kimberly K.; Robbins, Lisa L.

    1999-01-01

    Microbial calcification significantly impacts the cycling and deposition of inorganic carbon. This research employs 45Ca and 14C techniques as radioisotopic tracers to examine the role of cellular cycling of Ca2+ and inorganic carbon in CaCO3 precipitation by the unicellular green alga Nannochloris atomus. Implications of the effects of these physiological aspects on CaCO3 precipitation and the effects of microbial calcification on CaCO3 δ13C ratios are discussed. Results from pulse/chase experiments indicate that intracellular Ca2+ is incorporated into extracellular CaCO3. Intracellular inorganic carbon leaks from cells within 10 to 12 s after injection of unlabelled NaHCO3, providing a source of inorganic carbon for extracellular CaCO3. Cellular expulsion of calcium plays a key role in increasing the CaCO3 saturation state at the site of calcification. The δ13C ratios of microbial carbonates may vary depending on the amount of photorespiratory CO2 incorporated.

  14. Operational readiness review plan for the radioisotope thermoelectric generator materials production tasks

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.H.; Martin, M.M.; Riggs, C.R.; Beatty, R.L.; Ohriner, E.K.; Escher, R.N.

    1990-04-19

    In October 1989, a US shuttle lifted off from Cape Kennedy carrying the spacecraft Galileo on its mission to Jupiter. In November 1990, a second spacecraft, Ulysses, will be launched from Cape Kennedy with a mission to study the polar regions of the sun. The prime source of power for both spacecraft is a series of radioisotope thermoelectric generators (RTGs), which use plutonium oxide (plutonia) as a heat source. Several of the key components in this power system are required to ensure the safety of both the public and the environment and were manufactured at Oak Ridge National Laboratory (ORNL) in the 1980 to 1983 period. For these two missions, Martin Marietta Energy Systems, Inc. (Energy Systems), will provide an iridium-alloy component used to contain the plutonia heat source and a carbon-composite material that serves as a thermal insulator. ORNL alone will continue to fabricate the carbon-composite material. Because of the importance to DOE that Energy Systems deliver these high-quality components on time, performance of an Operational Readiness Review (ORR) of these manufacturing activities is necessary. Energy Systems Policy GP-24 entitled Operational Readiness Process'' describes the formal and comprehensive process by which appropriate Energy Systems activities are to be reviewed to ensure their readiness. This Energy System policy is aimed at reducing the risks associated with mission success and requires a management-approved readiness plan'' to be issued. This document is the readiness plan for the RTG materials production tasks. 6 refs., 11 figs., 1 tab.

  15. Radio-isotope production scale-up at the University of Wisconsin

    Energy Technology Data Exchange (ETDEWEB)

    Nickles, Robert Jerome [Univ of Wisconsin

    2014-06-19

    Our intent has been to scale up our production capacity for a subset of the NSAC-I list of radioisotopes in jeopardy, so as to make a significant impact on the projected national needs for Cu-64, Zr-89, Y-86, Ga-66, Br-76, I-124 and other radioisotopes that offer promise as PET synthons. The work-flow and milestones in this project have been compressed into a single year (Aug 1, 2012- July 31, 2013). The grant budget was virtually dominated by the purchase of a pair of dual-mini-cells that have made the scale-up possible, now permitting the Curie-level processing of Cu-64 and Zr-89 with greatly reduced radiation exposure. Mile stones: 1. We doubled our production of Cu-64 and Zr-89 during the grant period, both for local use and out-bound distribution to ≈ 30 labs nationwide. This involved the dove-tailing of beam schedules of both our PETtrace and legacy RDS cyclotron. 2. Implemented improved chemical separation of Zr-89, Ga-66, Y-86 and Sc-44, with remote, semi-automated dissolution, trap-and-release separation under LabView control in the two dual-mini-cells provided by this DOE grant. A key advance was to fit the chemical stream with miniature radiation detectors to confirm the transfer operations. 3. Implemented improved shipping of radioisotopes (Cu-64, Zr-89, Tc-95m, and Ho-163) with approved DOT 7A boxes, with a much-improved FedEx shipping success compared to our previous steel drums. 4. Implemented broad range quantitative trace metal analysis, employing a new microwave plasma atomic emission spectrometer (Agilent 4200) capable of ppb sensitivity across the periodic table. This new instrument will prove essential in bringing our radiometals into FDA compliance needing CoA’s for translational research in clinical trials. 5. Expanded our capabilities in target fabrication, with the purchase of a programmable 1600 oC inert gas tube furnace for the smelting of binary alloy target materials. A similar effort makes use of our RF induction furnace, allowing

  16. Radioisotope Power System Delivery, Ground Support and Nuclear Safety Implementation: Use of the Multi-Mission Radioisotope Thermoelectric Generator for the NASA's Mars Science Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    S.G. Johnson; K.L. Lively; C.C. Dwight

    2014-07-01

    Radioisotope power systems have been used for over 50 years to enable missions in remote or hostile environments. They are a convenient means of supplying a few milliwatts up to a few hundred watts of useable, long-term electrical power. With regard to use of a radioisotope power system, the transportation, ground support and implementation of nuclear safety protocols in the field is a complex process that requires clear identification of needed technical and regulatory requirements. The appropriate care must be taken to provide high quality treatment of the item to be moved so it arrives in a condition to fulfill its missions in space. Similarly it must be transported and managed in a manner compliant with requirements for shipment and handling of special nuclear material. This presentation describes transportation, ground support operations and implementation of nuclear safety and security protocols for a radioisotope power system using recent experience involving the Multi-Mission Radioisotope Thermoelectric Generator for National Aeronautics and Space Administration’s Mars Science Laboratory, which launched in November of 2011.

  17. Development of soft ionization using direct current pulse glow discharge plasma source in mass spectrometry for volatile organic compounds analysis

    Science.gov (United States)

    Nunome, Yoko; Kodama, Kenji; Ueki, Yasuaki; Yoshiie, Ryo; Naruse, Ichiro; Wagatsuma, Kazuaki

    2018-01-01

    This study describes an ionization source for mass analysis, consisting of glow discharge plasma driven by a pulsed direct-current voltage for soft plasma ionization, to detect toxic volatile organic compounds (VOCs) rapidly and easily. The novelty of this work is that a molecular adduct ion, in which the parent molecule attaches with an NO+ radical, [M + NO]+, can be dominantly detected as a base peak with little or no fragmentation of them in an ambient air plasma at a pressure of several kPa. Use of ambient air as the discharge plasma gas is suitable for practical applications. The higher pressure in an ambient air discharge provided a stable glow discharge plasma, contributing to the soft ionization of organic molecules. Typical mass spectra of VOCs toluene, benzene, o-xylene, chlorobenzene and n-hexane were observed as [M + NO]+ adduct ion whose peaks were detected at m/z 122, 108, 136, 142 and 116, respectively. The NO generation was also confirmed by emission bands of NO γ-system. The ionization reactions were suggested, such that NO+ radical formed in an ambient air discharge could attach with the analyte molecule.

  18. Study of acid solution bonding in epoxy matrix for sealed radioactive sources production

    Energy Technology Data Exchange (ETDEWEB)

    Benega, Marcos A.G.; Nagatomi, Helio R.; Rostelato, Maria Elisa C.M.; Tiezzi, Rodrigo; Rodrigues, Bruna T.; Peleias Junior, Fernando; Souza, Carla D.; Souza, Daiane C.C. de; Souza, Anderson S. de; Silva, Thais H. da, E-mail: carladdsouza@yahoo.com.br, E-mail: marcosagbenega@gmail.com, E-mail: hrnagato@ipen.br, E-mail: elisaros@ipen.br, E-mail: rktiezzi@gmail.com, E-mail: bteigarodrigues@gmail.com, E-mail: fernandopeleias@gmail.com, E-mail: dcsouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    The present work aims to analyze different resin formulations. These formulations are used in the production of radioactive sealed sources that are used in many fields such as nuclear medicine; environmental analyzes, radiation detectors accuracy check, and so on. These sources can be produced with different radioisotopes and different activities, it all depending on the use they will have. Certain types of resins have the same density water. This property is appreciated when we consider that radiotracers used in nuclear medicine are applied in aqueous solutions. So the sources used for checking and calibrating equipment must have their radioisotopes sealed in a material having similar properties, thus the measures are reproducible and repetitive. The most important aspect that is brought to attention in this work is the miscibility those resins have with water. The radioisotopes for the production of the sources are supplied in an aqueous form. In case the resin and the radioisotope solution do not mix, the source will not be sturdy enough to seal the radioisotopes in its structure and the source will not be safe. There were prepared different formulations with different amounts of acid solution, and the cured formulations were analyzed by Wipe Test, DSC (Differential Splanatory Calorimetry) and also, the possible volatile aspect of the radionuclide used. All to evaluate the integrity of the sources. The obtained results were satisfactory and show that when the resin is well cured, the radioisotope remains sealed in the matrix, making it possible to produce radioactive sealed sources. (author)

  19. The Texas A&M Radioisotope Production and Radiochemistry Program

    Energy Technology Data Exchange (ETDEWEB)

    Akabani, Gamal [Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering. Dept. of Veterinary Integrative Biosciences

    2016-10-28

    The main motivation of the project at Texas A&M University was to carry out the production of critically needed radioisotopes used in medicine for diagnostics and therapy, and to establish an academic program in radionuclide production and separation methods. After a lengthy battle with the Texas A&M University Radiation Safety Office, the Texas Department of State Health Services granted us a license for the production of radionuclides in July 2015, allowing us to work in earnest in our project objectives. Experiments began immediately after licensing, and we started the assembly and testing of our target systems. There were four analytical/theoretical projects and two experimental target systems. These were for At-211 production and for Zn-62/Cu-62 production. The theoretical projects were related to the production of Mo-99/Tc-99m using a) a subcritical aqueous target system and b) production of Tc-99m from accelerator-generated Mo-99 utilizing a photon-neutron interaction with enriched Mo-100 targets. The two experimental projects were the development of targetry systems and production of At-211 and Zn-62/Cu-62 generator. The targetry system for At-211 has been tested and production of At-211 is chronic depending of availability of beam time at the cyclotron. The installation and testing of the targetry system for the production of Zn-62/Cu-62 has not been finalized. A description of the systems is described. The academic program in radionuclide production and separation methods was initiated in the fall of 2011 and, due to the lack of a radiochemistry laboratory, it was suspended. We expect to re-start the academic program at the Texas A&M Institute for Preclinical Studies under the Molecular Imaging Program.

  20. The Texas A&M Radioisotope Production and Radiochemistry Program

    Energy Technology Data Exchange (ETDEWEB)

    Akabani, Gamal [Texas A & M Univ., College Station, TX (United States)

    2016-08-31

    The main motivation of the project at Texas A&M University was to carry out the production of critically needed radioisotopes used in medicine for diagnostic and therapy, and to establish an academic program in radionuclide production and separation methods. After a lengthy battle with the Texas A&M University Radiation Safety Office, the Texas Department of State Health Services granted us a license for the production of radionuclides in July 2015, allowing us to work in earnest in our project objectives. Experiments began immediately after licensing, and we started the assembly and testing of our target systems. There were four analytical/theoretical projects and two experimental target systems. These were for At-211 production and for Zn- 62/Cu-62 production. The theoretical projects were related to the production of Mo-99/Tc-99m using (a) a subcritical aqueous target system and (b) production of Tc-99m from accelerator-generated Mo-99 utilizing a photon-neutron interaction with enriched Mo-100 targets. The two experimental projects were the development of targetry systems and production of At-211 and Zn-62/Cu-62 generator. The targetry system for At-211 has been tested and production of At-211 is chronic depending of availability of beam time at the cyclotron. The installation and testing of the targetry system for the production of Zn-62/Cu-62 has not been finalized. A description of the systems is described. The academic program in radionuclide production and separation methods was initiated in the fall of 2011; due to the lack of a radiochemistry laboratory, it was suspended. We expect to re-start the academic program at the Texas A&M Institute for Preclinical Studies under the Molecular Imaging Program.

  1. Small Radioisotope Power System Testing at NASA Glenn Research Center

    Science.gov (United States)

    Dugala, Gina; Bell, Mark; Oriti, Salvatore; Fraeman, Martin; Frankford, David; Duven, Dennis

    2013-01-01

    In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer. A single ASC produces approximately 80 We making this system advantageous for small distributed lunar science stations. The IPT consists of Sunpower, Inc., to provide the single ASC with a passive balancer, The Johns Hopkins University Applied Physics Laboratory (JHUAPL) to design an engineering model Single Convertor Controller (SCC) for an ASC with a passive balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. The single ASC with a passive balancer, simulated lunar lander test stand, and SCC were delivered to GRC and were tested as a system. The testing sequence at GRC included SCC fault tolerance, integration, electromagnetic interference (EMI), vibration, and extended operation testing. The SCC fault tolerance test characterized the SCCs ability to handle various fault conditions, including high or low bus power consumption, total open load or short circuit, and replacing a failed SCC card while the backup maintains control of the ASC. The integrated test characterized the behavior of the system across a range of operating conditions, including variations in cold-end temperature and piston amplitude, including the emitted vibration to both the sensors on the lunar lander and the lunar surface. The EMI test characterized the AC and DC magnetic and electric fields emitted by the SCC and single ASC. The vibration test confirms the SCCs ability to control the single ASC during launch. The extended operation test allows data to be collected over a period of thousands of hours to obtain long term performance data of the ASC with a passive balancer and the SCC. This paper will discuss the results of each of these tests.

  2. Use of copper radioisotopes in investigating disorders of copper metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M. [University of Melbourne, Parkville, VIC (Australia). Department of Genetics; Smith, S. [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia). Radiopharmaceuticals Division; Mercer, J. [Deakin University, Rusden Campus, Clayton, VIC (Australia). Centre of Cellular and Molecular Biology

    1998-12-31

    Full text: Copper is an essential trace element for life as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Our studies have focused on Menkes disease in humans which is an inherited and usually lethal copper deficiency. Using copper radioisotopes {sup 64}Cu (t 1/2 = 12.8 hr) and {sup 67}Cu (t 1/2 = 61 hr) we have studied the protein which is mutated in Menkes disease. This is a transmembrane copper pump which is responsible for absorption of copper into the body and also functions to pump out excess Cu from cells when Cu is elevated. It is therefore a vital component of normal Cu homeostasis. We have provided the first biochemical evidence that the Menkes protein functions as a P-type ATPase Cu pump (Voskoboinik et al., FEBS Letters, in press) and these data will be discussed. The assay involved pumping of radiocopper into purified membrane vesicles. Furthermore we have transfected normal and mutant Menkes genes into cells and are carrying out structure-function studies. We are also studying the role of amyloid precursor protein (APP) as a Cu transport protein in order to determine how Cu regulates this protein and its cleavage products. These studies will provide vital information on the relationship between Cu and APP and processes which lead to Alzheimers disease

  3. Studies of copper transport in mammalian cells using copper radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M. [University of Melbourne, Parkville, VIC (Australia). Department of Genetics; Smith, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Radiopharmaceuticals Division; Mercer, J. [Deakin University, Clayton, VIC (Australia). Centre of Cellular and Molecular Biology

    1998-12-31

    The trace element copper poses a major problem for all organisms. It is essential as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Using the copper radioisotopes {sup 64}Cu (t1/2 = 12.8 hr) and {sup 67}Cu (t1/2 = 61 hr) we have developed a number of systems for studying copper transport in mammalian cells. These include investigation of copper uptake, copper efflux and ligand blot assays for Cu-binding proteins. Our studies have focused on Menkes disease which is an inherited and usually lethal copper deficiency disorder in humans. We have demonstrated that the Menkes protein is directly involved as a copper efflux pump in mammalian cells. Using cells overexpressing the Menkes protein we have provided the first biochemical evidence that this functions as a Cu translocating (across the membrane) P-type ATPase (Voskoboinik et al., FEBS Letters, in press). These studies were carried out using purified plasma membrane vesicles. We are now carrying out structure- function studies on this protein using targeted mutations and assaying using the radiocopper vesicle assay. Recently we have commenced studies on the role of amyloid precursor protein (APP) in copper transport and relationship of this to Alzheimers disease

  4. Radioisotope Productions for Medical Use with Accelerator Neutrons

    Science.gov (United States)

    Minato, Futoshi; Nagai, Yasuki; Iwamoto, Nobuyuki; Iwamoto, Osamu

    2014-09-01

    Various kinds of radioactive isotopes (RIs) are widely used in nuclear medicine for diagnostics and therapy. Since the RIs are not usually present in the nature, they must be produced by nuclear reactors and accelerators. For instance, 99mTc, which is the most common RI used in diagnosis, is mainly produced by fission of highly enriched 235U (HEU) in nuclear reactors. However, use of the HEU is unfavorable in terms of nuclear security. Therefore, many methods without 235U have been studied in order to produce RIs for medical use; for example, thermal neutron capture, gamma disintegration, and proton induced reactions. We also have proposed an alternative method using accelerator neutrons besides the above methods. Technique producing high intense accelerator neutron beam as much as 1015 n/s is being developed and RI productions with the accelerator neutron have been done recently. The major advantages of the use of accelerator neutron are followings. 1) A wide variety of carrier-added and carrier-free radioisotopes can be produced using the neutrons, because a charge exchange reaction of a sample nucleus has a sizable cross section of 50 to 500 mb. 2) High transparency of neutron allows us to use a large amount of sample to co-produce other RIs by putting other samples behind the main sample in the beam direction. In this talk, we will show the features of RI productions with accelerator neutron which we have ever investigated and found, along with numerical results of RI yields calculated with Japanese Evaluated Nuclear Data Library (JENDL-4.0).

  5. High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

    Science.gov (United States)

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1993-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

  6. Development and characterization of carbon-bonded carbon fiber insulation for radioisotope space power systems

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G.C.; Robbins, J.M.

    1985-06-01

    The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W(m.K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF superior to other known high-temperature insulation materials for the GPHS application have been identified. It has the excellent attributes of light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the GPHS application; it has passed vibration tests simulating launch conditions. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to incease the fabrication rate by a factor of 10. The specific properties of the CBCF were tailored by adjusting material and processing variables to obtain the desired results. We report here how work on CBCF characterization and development conducted at ORNL from 1978 through 1980 has contributed to the GPHS program to meet the requirements of both the Galileo and Ulysees Missions.

  7. Dose Calibrator Linearity Testing: Radioisotope (99m)Tc or (18)F? An Alternative for Reducing Costs in Nuclear Medicine Quality Control.

    Science.gov (United States)

    Willegaignon, José; Sapienza, Marcelo T; Coura-Filho, George Barberio; Garcez, Alexandre T; Alves, Carlos E; Cardona, Marissa R; Gutterres, Ricardo F; Buchpiguel, Carlos A

    2015-01-01

    Dose calibrator linearity testing is indispensable for evaluating the capacity of this equipment in measuring radioisotope activities at different magnitudes, a fundamental aspect of the daily routine of a nuclear medicine department, and with an impact on patient exposure. The main aims of this study were to evaluate the feasibility of substituting the radioisotope Fluorine-18 ((18)F) with Technetium-99m ((99m)Tc) in this test, and to indicate it with the lowest operational cost. The test was applied with sources of (99m)Tc (62 GBq) and (18)F (12 GBq), the activities of which were measured at different times, with the equipment preadjusted to measuring sources of (99m)Tc, (18)F, Gallium-67 ((67)Ga), and Iodine-131 ((131)I). Over time, the average deviation between measured and expected activities from (99m)Tc and (18)F were, respectively, 0.56 (±1.79)% and 0.92 (±1.19)%. The average ratios for 99(m)Tc source experimental activity, when measured with the equipment adjusted for measuring (18)F, (67)Ga, and (131)I sources, in real values, were, respectively, 3.42 (±0.06), 1.45 (±0.03), and 1.13 (±0.02), and those for the (18)F source experimental activity, measured through adjustments of (99m)Tc, (67)Ga, and (131)I, were, respectively, 0.295 (±0.004), 0.335 (±0.007), and 0.426 (±0.006). The adjustment of a simple exponential function for describing (99m)Tc and (18)F experimental activities facilitated the calculation of the physical half-lives of the radioisotopes, with a difference of about 1% in relation to the values described in the literature. Linearity test results, when using (99m)Tc, through being compatible with those acquired with (18)F, imply the possibility of using both radioisotopes during linearity testing. Nevertheless, this information, along with the high potential of exposure and the high cost of (18)F, implies that (99m)Tc should preferably be employed for linearity testing in clinics that normally use (18)F, without the risk of

  8. Lead shielded cells for the spectrographic analysis of radioisotope solutions; Descripcion de un equipo, con recintos blindados, para el analisis espectrografico de soluciones de radioisotopos

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M.; Capdevila, C.; Cruz, F. de la

    1967-07-01

    Two lead shielded cells for the spectrochemical analysis of radioisotope samples are described. One of them is devoted to the evaporation of samples before excitation and the other one contains a suitable spectrographic excitation stand for the copper spark technique. A special device makes it possible the easy displacement of the excitation cell on wheels and rails for its accurate and reproducible position as well as its replacement by a glove box for plutonium analysis. In order to guarantee safety the room in which the spectrograph and the source are set up in separated from the active laboratory by a wall with a suitable window. (Author) 1 refs.

  9. Generic inertia emulation controller for multi-terminal voltage-source-converter high voltage direct current systems

    DEFF Research Database (Denmark)

    Zhu, Jiebei; Guerrero, Josep M.; Hung, William

    2014-01-01

    A generic Inertia Emulation Controller (INEC) scheme for Multi-Terminal Voltage-Source-Converter based HVDC (VSC-MTDC) systems is proposed and presented in this paper. The proposed INEC can be incorporated in any Grid-side Voltage-Source-Converter (GVSC) station, allowing the MTDC terminal to con...

  10. Radiopharmaceuticals in positron emission tomography: Radioisotope productions and radiolabelling procedures at the Austin and Repatriation Medical Centre

    Energy Technology Data Exchange (ETDEWEB)

    Tochon-Danguy, H.J.; Sachinidis, J.I.; Chan, J.G.; Cook, M. [Austin and Repatriation Medical Centre, Melbourne, VIC (Australia). Centre for Positron Emission Tomography

    1997-10-01

    Positron Emission Tomography (PET) is a technique that utilizes positron-emitting radiopharmaceuticals to map the physiology, biochemistry and pharmacology of the human body. Positron-emitting radioisotopes produced in a medical cyclotron are incorporated into compounds that are biologically active in the body. A scanner measures radioactivity emitted from a patient`s body and provides cross-sectional images of the distribution of these radiolabelled compounds in the body. It is the purpose of this paper to review the variety of PET radiopharmaceuticals currently produced at the Austin and Repatriation Medical Centre in Melbourne. Radioisotope production, radiolabelling of molecules and quality control of radiopharmaceuticals will be discussed. A few examples of their clinical applications will be shown as well. During the last five years we achieved a reliable routine production of various radiopharmaceuticals labelled with the four most important positron-emitters: oxygen-15 (t,{sub 1/2}=2min), nitrogen-13 (t{sub 1/2}= 10 min), carbon-11 (t{sub 1/2}=20 min) and fluorine-18 (t{sub 1/2}= 110 min). These radiopharmaceuticals include [{sup 15}O]oxygen, [{sup 15}O]carbon monoxide, [{sup 15}O]carbon dioxide, [{sup 15}O]water, [{sup 13}N]ammonia, [{sup 11}C]flumazenil, [{sup 11}C]SCH23390, [{sup 18}F]fluoromisonidazole and [{sup 18}F]fluoro-deoxy-glucose ([{sup 18}F]FDG). In addition, since the half life of [{sup 18}F] is almost two hours, regional distribution can be done, and the Austin and Repatriation Medical Centre is currently supplying [{sup 18}F]FDG in routine to other hospitals. Future new radiopharmaceuticals development include a [{sup 18}F]thymidine analog to measure cell proliferation and a [{sup 11}C]pyrroloisoquinoline to visualize serotonergic neuron abnormalities. (authors) 23 refs., 2 tabs.

  11. Cost Comparison in 2015 Dollars for Radioisotope Power Systems -- Cassini and Mars Science Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Werner, James Elmer [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, Stephen Guy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dwight, Carla Chelan [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lively, Kelly Lynn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-07-01

    Radioisotope power systems (RPSs) have enabled missions requiring reliable, long-lasting power in remote, harsh environments such as space since the early 1960s. Costs for RPSs are high, but are often misrepresented due to the complexity of space missions and inconsistent charging practices among the many and changing participant organizations over the years. This paper examines historical documentation associated with two past successful flight missions, each with a different RPS design, to provide a realistic cost basis for RPS production and deployment. The missions and their respective RPSs are Cassini, launched in 1997, that uses the general purpose heat source (GPHS) radioisotope thermoelectric generator (RTG), and Mars Science Laboratory (MSL), launched in 2011, that uses the multi-mission RTG (MMRTG). Actual costs in their respective years are discussed for each of the two RTG designs and the missions they enabled, and then present day values to 2015 are computed to compare the costs. Costs for this analysis were categorized into two areas: development of the specific RTG technology, and production and deployment of an RTG. This latter category includes material costs for the flight components (including Pu-238 and fine weave pierced fabric (FWPF)); manufacturing of flight components; assembly, testing, and transport of the flight RTG(s); ground operations involving the RTG(s) through launch; nuclear safety analyses for the launch and for the facilities housing the RTG(s) during all phases of ground operations; DOE’s support for NEPA analyses; and radiological contingency planning. This analysis results in a fairly similar 2015 normalized cost for the production and deployment of an RTG—approximately $118M for the GPHS-RTG and $109M for the MMRTG. In addition to these two successful flight missions, the costs for development of the MMRTG are included to serve as a future reference. Note that development costs included herein for the MMRTG do not include

  12. Contributions and Future of Radioisotopes in Medical, Industrial and Space Applications

    Science.gov (United States)

    Tingey, G. L.; Dix, G. P.; Wahlquist, E. J.

    1990-11-01

    There are 333 isotopes that have a half-life between 1 day and 100,000 years that have a wide variety of applications including public health, medicine,industrial technology, food technology and packaging, agriculture, energy supply, and national security. This paper provides an overview of some of the most extensive applications of radioisotopes including some observations of future uses. Examples are discussed that indicate that the use of radioisotopes is almost unlimited and will continue to grow. There is a growing need for future applications development and production. 12 refs., 1 tab. (BM)

  13. Solid targets for production of radioisotopes with cyclotron; Blancos solidos para produccion de radioisotopos con ciclotron

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [Instituto Nacional de Investigaciones Nucleares, Direccion de Investigacion Tecnologica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    The design of targets for production of radioisotopes and radiopharmaceuticals of cyclotron to medical applications requires a detailed analysis of several variables such as: cyclotron operation conditions, choice of used materials as target and their physicochemical characteristics, activity calculation, the yielding of each radioisotope by irradiation, the competition of nuclear reactions in function of the projectiles energy and the collision processes amongst others. The objective of this work is to determine the equations for the calculation for yielding of solid targets at the end of the proton irradiation. (Author)

  14. Contributions and future of radioisotopes in medical, industrial and space applications

    Energy Technology Data Exchange (ETDEWEB)

    Tingey, G.L.; Dix, G.P.; Wahlquist, E.J.

    1990-11-01

    There are 333 isotopes that have a half-life between 1 day and 100,000 years that have a wide variety of applications including public health, medicine,industrial technology, food technology and packaging, agriculture, energy supply, and national security. This paper provides an overview of some of the most extensive applications of radioisotopes including some observations of future uses. Examples are discussed that indicate that the use of radioisotopes is almost unlimited and will continue to grow. There is a growing need for future applications development and production. 12 refs., 1 tab. (BM)

  15. Sintering trials of analogues of americium oxides for radioisotope power systems

    Science.gov (United States)

    Watkinson, E. J.; Ambrosi, R. M.; Kramer, D. P.; Williams, H. R.; Reece, M. J.; Chen, K.; Sarsfield, M. J.; Barklay, C. D.; Fenwick, H.; Weston, D. P.; Stephenson, K.

    2017-08-01

    European Space Agency radioisotope power systems will use americium oxide as the heat source in pellet or disc form. The oxide form is yet to be decided. Sintering trials with CeO2 and Nd2O3 as analogues for AmO2 and Am2O3 were conducted. Spark plasma sintering (SPS) and cold-press-and-sinter methods were compared. Different sintering parameters and particle characteristics were investigated with commercial and synthesised powders. The synthesised powders contained lath-shaped particles, and batches with different particle sizes and specific surface areas were made and sintered. This is the first study in the public literature to report the sintering of lath-shaped CeO2. The targeted density range of 85-90% was met using both techniques. No ball-milling was required. Cold-pressing-and-sintering CeO2 produced intact discs. Large cracking was prevalent in the SPS discs. Some powders pressed more successfully than others. Powder morphology had a significant effect on the result but it was not possible to fully quantify the effects in this study. The cold-pressed-and-sintered CeO2 discs had comparable Vickers hardness values to a nuclear ceramic (UO2). The hardness values were greater than the spark plasma sintered CeO2 sample. Efforts to SPS near-net shaped pellets using CeO2 and Nd2O3 are reported. A follow on investigation was conducted to assess how the 85-90% T.D. target could be achieved. The aspect ratio impacts the sintering parameters and behaviour. The Vickers hardness of Nd2O3 is reported for the first time and compared to the results of sintered CeO2.

  16. Actual and future situations of the use of radioisotopes; Situacion actual y futura del empleo de radioisotopos

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.C. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2005-07-01

    It is anticipated to medium term, an increase in the demand of the radioisotopes for medicine, industry and research, as well as the application of new radioisotopes derived from the development of new radiopharmaceuticals products for diagnosis and therapy applications. The personal and clinical dosimetry will have to be prepared for the new challenges. (Author)

  17. Fabrication of the Prototype Target Stack and Test Mock-up for the PEFP Radioisotope Production Facility

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S. P.; Park, B. S.; Kim, H. S.; Kwon, H. J.; Cho, Y. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The Proton Engineering Frontier Project have a plan to construct 100-MeV Proton Linear accelerator and also, will construct radioisotope production facility using 100MeV proton beam for medical application. Sr- 82, Cu-67 and Ge-68 were selected as the objective radioisotope in this facility. They are promising radioisotope for the PET imaging and cancer therapy. To produce Sr-82, Cu-67 and Ge-68, RbCl, Zn metal and Ga metal were chosen as a target materials which they have claddings of stainless steel or Inconel. and also to produce these radioisotopes at the same time, we have introduced target stack in tandem. Table 1 indicated the general characteristics of the designated radioisotopes

  18. Sediment source fingerprinting as an aid to catchment management: A review of the current state of knowledge and a methodological decision-tree for end-users.

    Science.gov (United States)

    Collins, A L; Pulley, S; Foster, I D L; Gellis, A; Porto, P; Horowitz, A J

    2017-06-01

    The growing awareness of the environmental significance of fine-grained sediment fluxes through catchment systems continues to underscore the need for reliable information on the principal sources of this material. Source estimates are difficult to obtain using traditional monitoring techniques, but sediment source fingerprinting or tracing procedures, have emerged as a potentially valuable alternative. Despite the rapidly increasing numbers of studies reporting the use of sediment source fingerprinting, several key challenges and uncertainties continue to hamper consensus among the international scientific community on key components of the existing methodological procedures. Accordingly, this contribution reviews and presents recent developments for several key aspects of fingerprinting, namely: sediment source classification, catchment source and target sediment sampling, tracer selection, grain size issues, tracer conservatism, source apportionment modelling, and assessment of source predictions using artificial mixtures. Finally, a decision-tree representing the current state of knowledge is presented, to guide end-users in applying the fingerprinting approach. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Development of a (170)Tm source for mercury monitoring studies in humans using XRF.

    Science.gov (United States)

    Timmaraju, K Phanisree; Fajurally, Bibi Najah; Armstrong, Andrea F; Chettle, David R

    2016-04-01

    The goals of the present study were to develop a (170)Tm radioisotope and generate a K XRF spectrum of mercury. Thulium foil and thulium oxide powder were both tested for impurities and the latter was found to be a better prospect for further studies. The (170)Tm radioisotope was developed from thulium oxide powder following the method of disolution and absorption. A suitable source holder and collimator were also designed based on Monte Carlo simulations. Using the radioisotope thus developed, a mercury XRF spectrum was successfully generated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Experimental demonstration of emission from a superluminal polarization current - a new class of solid-state source for MHz-THz and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, J. M. (John M.); Ardavan, A.; Ardavan, H.; Fopma, J.; Halliday, D.; Hayes, William

    2004-01-01

    We describe the Polarization Synchrotron, an experimental implementation of a superluminal (faster than light in vacuo) polarization current distribution that both oscillates and undergoes centripetal acceleration. The prototype machine produces tightly-beamed monochromatic radiation in the 100s of MHz range. The technique should also have applications as it broad-band GHz-THz source.

  1. Financing Adult Education: How Adequate Are Current Sources in Facilitating Access and Participation in Centres in Murang'a South Sub-County, Murang'a County, Kenya?

    Science.gov (United States)

    Maina, Ndonga James; Orodho, John Aluko

    2016-01-01

    The thrust of this study was to examine the level of adequacy of current sources in facilitating access and participation in adult education centres in Murang'a South Sub-County, Murang'a County, Kenya. The study adopted the descriptive survey design. Combinations of purposive and stratified random sampling techniques were used to select 82…

  2. Current control methods for grid-side three-phase PWM voltage-source inverter in distributed generation systems

    DEFF Research Database (Denmark)

    Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen

    2012-01-01

    A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich...

  3. Investigations in the modelling and control of a medium voltage hybrid inverter system that uses a low voltage /low power rated auxiliary current source inverter

    OpenAIRE

    Papadopoulos, Savvas; Rashed, Mohamed; Klumpner, Christian; Wheeler, Patrick

    2016-01-01

    Hybrid converters consist of a main inverter processing the bulk of the power with poor waveform performance and a fast and versatile auxiliary inverter to correct the distortion. In this paper, the main converter is a medium voltage NPC inverter and the auxiliary inverter is a low-voltage and low-current rated current source inverter (CSI), with series capacitor being used to minimize the CSI voltage stress. The result is a high output current quality which is obtained with a very low switch...

  4. Performance of cryocoolers in a High Temperature Superconducting ECR ion source (HTS-ECR) and its application for the High Current Injector Programme at IUAC, New Delhi

    Science.gov (United States)

    Rodrigues, G.; Mathur, Y.; Rao, U. K.; Lakshmy, P. S.; Mandal, A.; Roy, A.; Kanjilal, D.

    2017-02-01

    At the Inter University Accelerator Centre, a high current injector programme (HCI) is being developed as an alternate injector to the superconducting linear accelerator (SC-LINAC). For this purpose, a high temperature superconducting ECR ion source, PKDELIS, based on Gifford McMahon cryocoolers was designed, installed and commissioned in the Low Energy Beam Transport section of the high current injector. The ion source will inject multiply charged ions having A/q ∼ 6 for further acceleration into the downstream RFQ and DTL accelerators before final injection into the superconducting linear accelerator. The details of the design, and experimental results of the ion source together with performance of the cryocoolers are presented in this paper.

  5. Assessing the Applicability of Currently Available Methods for Attributing Foodborne Disease to Sources, Including Food and Food Commodities

    DEFF Research Database (Denmark)

    Pires, Sara Monteiro

    2013-01-01

    illness caused by enteric, parasitic, and chemical foodborne hazards to the responsible sources; and renamed some of the approaches. The main objective was to make recommendations on the most appropriate method(s) to attribute human disease caused by different foodborne hazards. We concluded......Abstract A variety of approaches to attribute foodborne diseases to specific sources are available, including hazard occurrence analysis, epidemiological methods, intervention studies, and expert elicitations. The usefulness of each method to attribute disease caused by a foodborne hazard depends...... on the public health question being addressed, on the data requirements, on advantages and limitations of the method, and on the data availability of the country or region in question. Previous articles have described available methods for source attribution, but have focused only on foodborne microbiological...

  6. An evaluation of alternate production methods for Pu-238 general purpose heat source pellets

    Energy Technology Data Exchange (ETDEWEB)

    Mark Borland; Steve Frank

    2009-06-01

    For the past half century, the National Aeronautics and Space Administration (NASA) has used Radioisotope Thermoelectric Generators (RTG) to power deep space satellites. Fabricating heat sources for RTGs, specifically General Purpose Heat Sources (GPHSs), has remained essentially unchanged since their development in the 1970s. Meanwhile, 30 years of technological advancements have been made in the applicable fields of chemistry, manufacturing and control systems. This paper evaluates alternative processes that could be used to produce Pu 238 fueled heat sources. Specifically, this paper discusses the production of the plutonium-oxide granules, which are the input stream to the ceramic pressing and sintering processes. Alternate chemical processes are compared to current methods to determine if alternative fabrication processes could reduce the hazards, especially the production of respirable fines, while producing an equivalent GPHS product.

  7. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health

    DEFF Research Database (Denmark)

    Stephen, Alison M; Champ, Martine M-J; Cloran, Susan J

    2017-01-01

    Research into the analysis, physical properties and health effects of dietary fibre has continued steadily over the last 40-50 years. From the knowledge gained, countries have developed guidelines for their populations on the optimal amount of fibre to be consumed each day. Food composition table...... advice to the public about specific food sources that should be consumed to achieve health benefits....

  8. The use of radioisotopes in medicine and medical research, Australia 1947-73

    Energy Technology Data Exchange (ETDEWEB)

    Korszniak, N

    1994-12-01

    On March 31, 1994, an article appeared in the Melbourne Age claiming that after the Second World War `hundreds of people were injected with radioactive materials in medical experiments that continued in Australian hospitals until the 1960s. Similar reports subsequently appeared in other newspapers and on the television and radio news. The archival records held at the Australian Radiation Laboratory (ARL) pertaining to the medical uses of radioisotopes during the period 1947-1973 have been examined to ascertain the nature of radioisotope use, and in the case of experimental procedures, any ethical considerations. The material examined indicates that the distribution and medical use of radioactive isotopes was stringently controlled by the Radio-isotope Standing Committee (established by the National Health and Medical Research Council (NHMRC) in 1947 to oversee this area) until its disbandment in 1973, when the responsibility for regulation of the use of radioactive isotopes for medical purposes in Australia passed to the Therapeutic Goods Administration. A database, showing details of over 500 radioisotope use in Australia between 1947-1973 is given in Appendix III . (author) refs., tabs.

  9. Dose estimate of exposure to radioisotopes in molecular and cellular biology

    Energy Technology Data Exchange (ETDEWEB)

    Onado, C.; Faretta, M.; Ubezio, P. [Unitadi Biofisica, Istituto di Ricerche Farmacologiche ' Mario Negri' , Milano (Italy)

    1999-06-01

    A method for prospectively evaluating the annual equivalent doses and effective dose to biomedical researchers working with unsealed radioisotopes, and their classification, is presented here. Simplified formulae relate occupational data to a reasonable overestimate of the annual effective dose, and the equivalent doses to the hands and to the skin. The procedure, up to the classification of personnel and laboratories, can be made fully automatic, using a common spreadsheet on a personal computer. The method is based on occupational data, accounting for the amounts of each radioisotope used by a researcher, the time of exposure and the overall amounts employed in the laboratories where experiments are performed. The former data serve to forecast a contribution to the dose arising from a researcher's own work, the latter to a forecast of an 'environmental' contribution deriving simply from the presence in a laboratory where other people are working with radioisotopes. The estimates of the doses due to one's own radioisotope handling and to 'environment' were corrected for accidental exposure, considered as a linear function of the manipulated activity or of the time spent in the laboratories respectively, and summed up to give the effective dose. The effective dose associated with some common experiments in molecular and cellular biology is pre-evaluated by this method. (author)

  10. Clouds, airplanes, trucks and people: carrying radioisotopes to and across Mexico.

    Science.gov (United States)

    Mateos, Gisela; Suárez-Díaz, Edna

    2015-01-01

    The aim of this paper is to describe the early stages of Mexican nuclearization that took place in contact with radioisotopes. This history requires a multilayered narrative with an emphasis in North-South asymmetric relations, and in the value of education and training in the creation of international asymmetrical networks. Radioisotopes were involved in exchanges with the United States since the late 1940s, but also with Canada. We also describe the context of implementation of Eisenhower's Atoms for Peace initiative in Mexico that opened the door to training programs at both the Comisión Nacional de Energía Nuclear and the Universidad Nacional Autónoma de México. Radioisotopes became the best example of the peaceful applications of atomic energy, and as such they fitted the Mexican nuclearization process that was and still is defined by its commitment to pacifism. In 1955 Mexico became one of the 16 members of the atomic fallout network established by the United Nations. As part of this network, the first generation of Mexican (women) radio-chemists was trained. By the end of the 1960s, radioisotopes and biological markers were being produced in a research reactor, prepared and distributed by the CNEN within Mexico. We end up this paper with a brief reflection on North-South nuclear exchanges and the particularities of the Mexican case.

  11. The study on the adaptation for regulation - the permission of a radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung Il; Choi, Won Seok; Jung, Yong Moon [Gallup Korea, Seoul (Korea, Republic of)

    2003-08-15

    The restriction -the permission of a radioisotope keeps satisfaction with almost parts for example, awareness, observance and so on. Moreover two concepts are considered fully -too strict about certain specific control rules and needed more discriminated application standards to each organization related to KINS, it's preserved and controlled properly even if the penalties are downsized.

  12. Summary, the 20th quality control survey for radioisotopes in vitro tests in Japan, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    For advancement of radioisotope in vitro tests such as radioimmunoassay and immunoradiometric assay, the Subcommittee for Radioisotope in vitro Test in Medical and Pharmaceutical Committee of Japan Radioisotope Association has conducted the yearly quality control survey for the test facilities in Japan since 1978. This is the summary of the 20th survey in 1998 where non-radioisotope tests like enzyme-immunoassay were involved as well. The survey was done for 143 facilities: 20 national and public university hospitals, 18 private university hospitals, 8 national hospitals, 13 public hospitals, 21 private hospitals, 41 hygienic laboratories and 22 manufacturers of reagents. Facilities examined intra- and between day-reproducibility, freeze-thaw effect and time change of the measured values on the same samples. Assays were for: growth hormone (h), somatomedin C, follicle stimulating h, luteinizing h, prolactin, thyroid stimulating h, triiodothyronines, thyroxines, thyroxine binding protein, calcitonin, insulin, C-peptide, glucagons, gastrin, testosterones, estradiol, progesterone, gonadotropin, 17{alpha}-hydroxyprogesterone, aldosterone, cortisol, dehydroepiandorosterone sulfate, renin, IgE, digoxin, {alpha}-fetoprotein, carcinoembryonic antigen, tissue polypeptide antigen, CA (125, 19-9 and 15-3), prostatic acid phosphatase, prostate specific antigen, {beta}2-microglobulin, ferritin, and neuron specific enolase. There was no great difference between this and last survey results although tendency of improvement was recognized. There were problems to be solved from the standpoint of clinical practice. (K.H.)

  13. Fractal Dimensions for Radioisotope Pollution Patterns by Nuclear Power Plant Accidents

    Science.gov (United States)

    Saito, K.; Ogawa, S.

    2015-04-01

    The radioisotope pollution shows two types of patterns: dry and wet deposits for nuclear power plant accidents. Two surface pollution patterns were analysed by fractal. In Fukushima nuclear power plant accident, surface pollution by wet deposits was estimated to occur. However, actually it was no rain and white crystals were observed on the surface. Then, fractal analysis was carried out for the spatial distribution patterns of radio isotopes on the surface to judge the types of deposits. As a reference, Chernobyl nuclear power plant accident was checked for the spatial distribution patterns of radioisotopes on the surface. The objective patterns by fractal analysis were the surface pollution maps in Fukushima and Chernobyl, Abukuma river watershed map, and NOAA/AVHRR. The calculation of fractal dimensions was carried out with the box counting for binarized images. Fractal analysis results suggested the next conclusions. The radioisotope pollution in Fukushima might occur in both dry and wet deposits. The dry deposit might make the pollution pattern similar to the watershed, while the wet deposit might make the pollution pattern similar to cloud images. Moreover, most radioisotope contaminants might flow on the road in the forest valley and deposit on forest with and without rainfall in Fukushima.

  14. Preparation of the Nanostructured Radioisotope Metallic Oxide by Neutron Irradiation for Use as Radiotracers

    Directory of Open Access Journals (Sweden)

    Sang-Ei Seo

    2017-10-01

    Full Text Available Metallic oxides manganese dioxide (MnO2, samarium oxide (Sm2O3, and dysprosium oxide (Dy2O3 with nanorod-like structures were synthesized by the hydrothermal synthesis method, respectively. Subsequently, the nanostructured radioisotopes MnO2 with Mn-56, Sm2O3 with Sm-153, and Dy2O3 with Dy-165 were prepared by neutron irradiation from the HANARO research reactor, respectively. The three different elements, Mn, Sm, and Dy, were selected as radiotracers because these elements can be easily gamma-activated from neutrons (activation limits: 1 picogram (Dy, 1–10 picogram (Mn, 10–100 picogram (Sm. Furthermore, the synthesized radioisotopes can be used as radiotracers in Prompt Gamma Neutron Activation Analysis as the rare earth metals Dy and Sm were not present in the Korean environment. The successful synthesis of the radioisotope metallic oxides was confirmed by Transmission Electron Microscopy (TEM, Energy Dispersive X-ray Spectrometry (EDS, X-ray Diffraction (XRD analysis, and gamma spectroscopy analysis. The synthesized nanostructured radioisotope metallic oxides may be used as radiotracers in scientific, environmental, engineering, and industrial fields.

  15. 76 FR 63668 - Guidelines for Preparing and Reviewing Licensing Applications for the Production of Radioisotopes

    Science.gov (United States)

    2011-10-13

    ... construction and operating license for a radioisotope production facility and the Research and Test Reactor... Reactors Licensing Branch, Division of Policy and Rulemaking, Office of Nuclear Reactor Regulation, U.S... the Nuclear Regulatory Commission. Patricia A. Silva, Chief, Research and Test Reactors Projects...

  16. Application of radioisotopes Au -198 to radiometrical field investigation of spraying machine

    Energy Technology Data Exchange (ETDEWEB)

    Goraczko, W.; Kocorowska, E. [Technical Univeristy, Poznan (Poland). Radio and Photo-Chemistry Department

    1997-10-01

    The poster shows application of radioisotope {sup 198}Au to radiometrical field testing of spraying machine. In the research was tested the Polish suspensioned tractor OZS400 type spraying machine. The machine worked in two different variants: without and with the beam stabilisation (oscillatory stabilisation)

  17. Americium Oxide Surrogates for European Radioisotope Power Systems.

    Science.gov (United States)

    Watkinson, E. J.; Ambrosi, R. M.; Williams, H. R.; Sarsfield, M. J.; Tinsley, T. P.; Stephenson, K.

    2014-07-01

    The European space nuclear power programme comprises two main research areas: fuel source development and the development of conversion technologies, which are thermoelectric or dynamic, for electricity production. This abstract addresses the former.

  18. Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron.

    Science.gov (United States)

    Hojo, S; Katagiri, K; Nakao, M; Sugiura, A; Muramatsu, M; Noda, A; Okada, T; Takahashi, Y; Komiyama, A; Honma, T; Noda, K

    2014-02-01

    The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

  19. Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

    Science.gov (United States)

    Hojo, S.; Katagiri, K.; Nakao, M.; Sugiura, A.; Muramatsu, M.; Noda, A.; Okada, T.; Takahashi, Y.; Komiyama, A.; Honma, T.; Noda, K.

    2014-02-01

    The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C4+ ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C4+, for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

  20. Radioisotopes production for applications on the health; Produccion de radioisotopos para aplicaciones en la salud

    Energy Technology Data Exchange (ETDEWEB)

    Monroy G, F.; Alanis M, J., E-mail: fabiola.monroy@inin.gob.m [ININ, Departamento de Materiales Radiactivos, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    In the Radioactive Materials Department of the Instituto Nacional de Investigaciones Nucleares (ININ) processes have been studied and developed for the radioisotopes production of interest in the medicine, research, industry and agriculture. In particular five new processes have been developed in the last 10 years by the group of the Radioactive Materials Research Laboratory to produce: {sup 99}Mo/{sup 99m}Tc and {sup 188}W/{sup 188}Re generators, the radio lanthanides: {sup 151}Pm, {sup 147}Pm, {sup 161}Tb, {sup 166}Ho, {sup 177}Lu, {sup 131}I and the {sup 32}P. All these radioisotopes are artificial and they can be produced in nuclear reactors and some of them in particle accelerators. The radioisotope generators are of particular interest, as those of {sup 99}Mo/{sup 99m}Tc and {sup 188}W/{sup 188}Re presented in this work, because they are systems that allow to produce an artificial radioisotope of interest continually, in these cases the {sup 99m}Tc and the {sup 188}Re, without the necessity of having a nuclear reactor or an particle accelerator. They are compact systems armored and sure perfectly of manipulating that, once the radioactive material has decayed, they do not present radiological risk some for the environment and the population. These systems are therefore of supreme utility in places where it is not had nuclear reactors or with a continuous radioisotope supply, due to their time of decaying, for its cost or for logistical problems in their supply, like it is the case of many hospital centers, of research or industries in our country. (Author)

  1. The improvement of the education courses on radiation protection and radioisotope handling

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Han Suk; Kim, Woong Ki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    About 48,000 nuclear personnel and 10,000 radioisotope personnel have participated in the KAERI-NTC's education and training programs. For the needs of personnel in radioisotope and radiation handling, KAERI-NTC has operated a class-room based full-time course for 4 weeks for applicants of a general license and 6 weeks for applicants of supervisor license. These courses educated almost 3,908 trainees for general radioisotope handling and 1,856 trainees for supervisors of radiation handling. Since the Korean Association for Radiation Application (KARA) was established in 1985 and the Korea Academy of Nuclear Safety (KANS) was established in 2002, KARA and KANS have operated with a non-classroom based correspondence course. According to this role separation in training radioisotope handling personnel, KAERI-NTC tried to improve the classroom based courses. The number of applicants of general radioisotope handling in recent years is increasing around 3,000 - 4,000 in a year. The real participants in an general license test are 2,105 to 2,841 in 2013 and 2014. The ratio of successful applicants in general isotope handling are just the 23% in 2013 and 4.2% in 2014. Addressing this low ratio of successful applicants, several proactive measures in KAERI-NTC were considered to enhance these courses for general users and supervisors. The purpose of this paper is to provide. For the further development of these courses, our measures were classified the measures in the Implementation stage of the ADDIE model. In addition to this Implementation stage, it is recommended that these actions should be applied to the other stages of ADDIE such as Analysis, Design, Development and Evaluation.

  2. A control strategy for a distributed power generation microgrid application with voltage and current controlled source converter

    OpenAIRE

    Serban, E; Serban, H

    2010-01-01

    This paper presents a pseudodroop control structure integrated within a microgrid system through distributed power generation (DPG) modules capable to function in off-grid islanded, genset-connected, and grid-connected modes of operation. System efficiency has an important role in order to harvest the maximum available renewable energy from dc or ac sources while providing power backup capability. A control strategy is proposed in off-grid islanded mode method based on the microgrid line-freq...

  3. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health

    DEFF Research Database (Denmark)

    Stephen, Alison M; Champ, Martine M-J; Cloran, Susan J

    2017-01-01

    , particularly from national surveys across Europe and around the world. It also assessed current knowledge on health effects of dietary fibre and related the impact of different fibre types on health. The overall intent was to be able to provide more detailed guidance on the types of fibre which should...... be consumed for good health, rather than simply a total intake figure, the current situation. Analysis of data indicated a fair degree of uniformity in the definition of dietary fibre, the method used for analysis, the recommended amount to be consumed and a growing literature on effects on digestive health...

  4. Regulations concerning the radionuclides uses in France; Reglementation de l'utilisation des radioisotopes en France

    Energy Technology Data Exchange (ETDEWEB)

    Vergne, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Bugnard, L. [Institut national d' Hygiene (France)

    1955-07-01

    The progress in the uses of radioisotopes has been conditioned by increasing the number of trained workers and researchers and developing theoretical teaching in universities since 1950 in France as well as developing a national control of the distribution and uses of radioisotopes. With the large diffusion and development of radioisotopes uses and applications, new rules and regulations came to control the importation, exportation, transport and utilization of radioisotopes. In the first part, it described the different French laws since 1934 and their successive modifications which ruled on the production, manipulation and utilization of radioisotopes. An inter-ministerial committee was created in 1952 to advise and inform of all the questions related to the preparation, importation, exportation, possession and distribution of radioisotopes. The transport regulations are in constant evolution and has got to meet with international recommendations. It distinguished three different type of transport: road, river and railway transport, postal transport and finally air transport. All the different transports have their specific packaging, maximum transportable quantity, maximum material intensity and labelling requirements. The regulations about customs duties are specified as well as the administrative formalities for non natural radioisotopes importation. Since 1950, diseases caused by irradiation to natural or artificial radioactive materials are recognised as professional diseases and a table of the actual regulations is presented. (M.P.)

  5. SIMULATION OF A HIGH-POWERED VARIABLE FREQUENCY AC DRIVE BASED ON A MULTIPULSE CURRENT SOURCE INVERTER

    Directory of Open Access Journals (Sweden)

    G.G. Zhemerov

    2013-10-01

    Full Text Available A computer model building technique for an AC drive system with an autonomous 24-pulse current inverter is introduced. On the basis of the technique developed, a MATLAB variable-frequency drive model capable of working in both quasi-stationary and transient modes is built.

  6. Estimating urban forest carbon sequestration potential in the southern United States using current remote sensing imagery sources

    Science.gov (United States)

    Krista Merry; Pete Bettinger; Jacek Siry; J. Michael Bowker

    2015-01-01

    With an increased interest in reducing carbon dioxide in the atmosphere, tree planting and maintenance in urban areas has become a viable option for increasing carbon sequestration. Methods for assessing the potential for planting trees within an urban area should allow for quick, inexpensive, and accurate estimations of available land using current remote sensing...

  7. Assessment of great ocean currents as a source of renewable energy using recent OGCM simulations of the global ocean

    Science.gov (United States)

    Barnier, Bernard; Domina, Anastasiia; Maitre, Thierry; Molines, Jean-Marc; Penduff, Thierry; Le Sommer, Julien; Brasseur, Pierre; Gulev, Sergey

    2017-04-01

    The great wind-driven ocean currents (e.g. Gulf-Stream or Kuroshio) are relatively constant in strength and direction, and they carry a great deal of energy because of the density of water. Technologies are being developed to extract energy from those currents and convert it into a usable power. The paper presents a methodology used to select regions of the global ocean where the properties of the great ocean currents are favourable to the implementation of Turbine Power Plants (TPP) made of submerged rotors driven by the motion of water. The methodology relies on a state-of-the-art eddy-resolving global ocean general circulation model used for real-time ocean forecasting, in which the implementation of a large TPP is represented by an additional drag force applied locally. This system is able to simulate the flow changes induced by the implementation of a power plant in the current, and consequently provides an assessment of the renewable energy that could be recovered and of the possible environmental impact. Our results demonstrate that the flow changes induced by a large TPP (covering the area of a model grid size, i.e. a few km) are highly dependent on the details of local topography, leading to a reduction of the available power that can vary from 25% to 85% according to location. We shall also show that impact of a TPP on the flow can be felt a few 100 kilometres upstream and may in some cases not only impact the flow speed, but also induce a large shift of the main current path.

  8. Tube Current Modulation Between Single- and Dual-Energy CT With a Second-Generation Dual-Source Scanner: Radiation Dose and Image Quality.

    Science.gov (United States)

    Matsubara, Kosuke; Takata, Tadanori; Kobayashi, Masanao; Kobayashi, Satoshi; Koshida, Kichiro; Gabata, Toshifumi

    2016-08-01

    The purpose of this study was to compare the effects of tube current modulation between single- and dual-energy CT with a second-generation dual-source scanner. Custom-made elliptic polymethylmethacrylate phantoms for slim and large patients were used. Absorbed radiation dose at the central point of the phantoms was measured with a solid-state detector while the phantoms were scanned in single-energy (120 kV) and dual-energy (100/Sn140, 80/Sn140, and 140/80 kV) modes with a second-generation dual-source CT scanner. Tube current modulation was activated in both modes, and quality reference tube current-time settings of 150, 300, 450, and 600 mAs were selected. Scanning was performed three times under the same conditions, and image noise was evaluated by measuring the SD of CT numbers in four separate regions of three adjacent images of the phantoms. Absorbed dose increased and image noise decreased with an increase in quality reference tube current-time setting when the slim phantom was scanned. For the large phantom, the radiation dose and noise level reached a plateau above quality reference tube current-time settings of 300 mAs for 100/Sn140 kV and 450 mAs for 120 kV. The radiation dose was small and the noise level was large with 80/Sn140 kV compared with that obtained with 120 and 100/Sn140 kV at all quality reference tube current-time settings. When a large phantom is scanned with 100/Sn140 kV, exposure demand for tube current modulation exceeds system limits at a lower quality reference tube current-time setting than for scanning 120 kV.

  9. Design of current source DC/DC converter and inverter for 2kW fuel cell application

    DEFF Research Database (Denmark)

    Andreiciks, A.; Steiks, I.; Krievs, O.

    2013-01-01

    In order to use hydrogen fuel cell in domestic applications either as main power supply or backup power source, the low DC output voltage of the fuel cell has to be matched to the voltage level and frequency of the utility grid AC voltage. The interfacing power converter systems usually consist...... of a DC/DC converter and an inverter. In this paper a detailed simulation study of such interfacing converter system comprising a double inductor push-pull step-up DC/DC converter and a cascaded H-bridge inverter has been carried out and further confirmed with experimental results. The power converter...

  10. Modeling non-steady state radioisotope transport in the vadose zone - A case study using uranium isotopes at Peña Blanca, Mexico

    Science.gov (United States)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-10-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and 234U/ 238U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and α-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Peña Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced 234U/ 238U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using 234U/ 238U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  11. Modeling non-steady state radioisotope transport in the vadose zone--A case study using uranium isotopes at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-06-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and {sup 234}U/{sup 238}U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and {alpha}-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Pena Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced {sup 234}U/{sup 238}U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using {sup 234}U/{sup 238}U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  12. Analytical Subthreshold Current and Subthreshold Swing Models for a Fully Depleted (FD) Recessed-Source/Drain (Re-S/D) SOI MOSFET with Back-Gate Control

    Science.gov (United States)

    Saramekala, Gopi Krishna; Tiwari, Pramod Kumar

    2017-08-01

    Two-dimensional (2D) analytical models for the subthreshold current and subthreshold swing of the back-gated fully depleted recessed-source/drain (Re-S/D) silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) are presented. The surface potential is determined by solving the 2D Poisson equation in both channel and buried-oxide (BOX) regions, considering suitable boundary conditions. To derive closed-form expressions for the subthreshold characteristics, the virtual cathode potential expression has been derived in terms of the minimum of the front and back surface potentials. The effect of various device parameters such as gate oxide and Si film thicknesses, thickness of source/drain penetration into BOX, applied back-gate bias voltage, etc. on the subthreshold current and subthreshold swing has been analyzed. The validity of the proposed models is established using the Silvaco ATLAS™ 2D device simulator.

  13. Pathways of PFOA to the Arctic: variabilities and contributions of oceanic currents and atmospheric transport and chemistry sources

    Directory of Open Access Journals (Sweden)

    I. Stemmler

    2010-10-01

    Full Text Available Perfluorooctanoic acid (PFOA and other perfluorinated compounds are industrial chemicals in use for decades which resist degradation in the environment and seem to accumulate in polar regions. Transport of PFOA was modeled using a spatially resolved global multicompartment model including fully coupled three-dimensional ocean and atmosphere general circulation models, and two-dimensional top soil, vegetation surfaces, and sea ice compartments. In addition to primary emissions, the formation of PFOA in the atmosphere from degradation of 8:2 fluorotelomer alcohol was included as a PFOA source. Oceanic transport, delivered 14.8±5.0 (8–23 t a−1 to the Arctic, strongly influenced by changes in water transport, which determined its interannual variability. This pathway constituted the dominant source of PFOA to the Arctic. Formation of PFOA in the atmosphere led to episodic transport events (timescale of days into the Arctic with small spatial extent. Deposition in the polar region was found to be dominated by wet deposition over land, and shows maxima in boreal winter. The total atmospheric deposition of PFOA in the Arctic in the 1990s was ≈1 t a−1, much higher than previously estimated, and is dominated by primary emissions rather than secondary formation.

  14. An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2015-07-01

    Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary  frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

  15. Extension of the source-sink potential approach to Hartree-Fock and density functional theory: A new tool to visualize the ballistic current through molecules

    Science.gov (United States)

    Fias, Stijn; Stuyver, Thijs

    2017-11-01

    The recent source and sink potential approach by Pickup et al. [J. Chem. Phys. 143, 194105 (2015)] is extended to Hartree-Fock and density functional theory, allowing the calculation of the transmission and the visualization of ballistic currents through molecules at these levels of theory. This visualization allows the study of the transmission process in real-space, providing an important tool to better understand the conduction process.

  16. Generation of multi-charged high current ion beams using the SMIS 37 gas-dynamic electron cyclotron resonance (ECR) ion source

    Energy Technology Data Exchange (ETDEWEB)

    Dorf, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zorin, V. G. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Sidorov, A. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Bokhanov, A. F. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Izotov, I. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Razin, S. V. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics; Skalyga, V. A. [Russian Academy of Sciences (RAS), Nizhny Novgorod (Russian Federation). Inst. of Applied Physics

    2013-06-02

    A gas-dynamic ECR ion source (GaDIS) is distinguished by its ability to produce high current and high brightness beams of moderately charged ions. Contrary to a classical ECR ion source where the plasma confinement is determined by the slow electron scattering into an empty loss-cone, the higher density and lower electron temperature in a GaDIS plasma lead to an isotropic electron distribution with the confinement time determined by the prompt gas-dynamic flow losses. As a result, much higher ion fluxes are available, however a decrease in the confinement time of the GaDIS plasma lowers the ion charge state. The gas-dynamic ECR ion source concept has been successfully realized in the SMIS 37 experimental facility operated at the Institute of Applied Physics, Russia. The use of high-power (~100 kW) microwave (37.5 GHz) radiation provides a dense plasma (~1013 cm-3) with a relatively low electron temperature (~50- 100 eV) and allows for the generation of high current (~1 A/cm2) beams of multi-charged ions. In this work we report on the present status of the SMIS 37 ion source and discuss the advanced numerical modeling of ion beam extraction using the particle-in-cell code WARP

  17. Effect of Sertraline on Current-Source Distribution of the High Beta Frequency Band: Analysis of Electroencephalography under Audiovisual Erotic Stimuli in Healthy, Right-Handed Males.

    Science.gov (United States)

    Lee, Seung Hyun; Hyun, Jae Seog; Kwon, Oh-Young

    2010-08-01

    The purpose of this study was to examine the cerebral changes in high beta frequency oscillations (22-30 Hz) induced by sertraline and by audiovisual erotic stimuli in healthy adult males. Scalp electroencephalographies (EEGs) were conducted twice in 11 healthy, right-handed males, once before sertraline intake and again 4 hours thereafter. The EEGs included four sessions recorded sequentially while the subjects were resting, watching a music video, resting, and watching an erotic video for 3 minutes, 5 minutes, 3 minutes, and 5 minutes, respectively. We performed frequency-domain analysis using the EEGs with a distributed model of current-source analysis. The statistical nonparametric maps were obtained from the sessions of watching erotic and music videos (p<0.05). The erotic stimuli decreased the current-source density of the high beta frequency band in the middle frontal gyrus, the precentral gyrus, the postcentral gyrus, and the supramarginal gyrus of the left cerebral hemisphere in the baseline EEGs taken before sertraline intake (p<0.05). The erotic stimuli did not induce any changes in current-source distribution of the brain 4 hours after sertraline intake. It is speculated that erotic stimuli may decrease the function of the middle frontal gyrus, the precentral gyrus, the postcentral gyrus, and the supramarginal gyrus of the left cerebral hemisphere in healthy adult males. This change may debase the inhibitory control of the brain against erotic stimuli. Sertraline may reduce the decrement in inhibitory control.

  18. Current and future trends in fecal source tracking and deployment in the Lake Taihu Region of China

    Science.gov (United States)

    Hagedorn, Charles; Liang, Xinqiang

    The emerging discipline of microbial and/or chemical source tracking (collectively termed fecal source tracking (FST)) is being used to identify origins of fecal contamination in polluted waters in many countries around the world. FST has developed rapidly because standard methods of measuring contamination in water by enumerating fecal indicator bacteria (FIB) such as fecal coliforms and enterococci do not identify the sources of the contamination. FST is an active area of research and development in both the academic and private sectors and includes: Developing and testing new microbial and chemical FST methods. Determining the geographic application and animal host ranges of existing and emerging FST techniques. Conducting experimental comparisons of FST techniques. Combining direct monitoring of human pathogens associated with waterborne outbreaks and zoonotic pathogens responsible for infections among people, wildlife, or domesticated animals with the use of FST techniques. Applying FST to watershed analysis and coastal environments. Designing appropriate statistical and probability analysis of FST data and developing models for mass loadings of host-specific fecal contamination. This paper includes a critical review of FST with emphasis on the extent to which methods have been tested (especially in comparison with other methods and/or with blind samples), which methods are applicable to different situations, their shortcomings, and their usefulness in predicting public health risk or pathogen occurrence. In addition, the paper addresses the broader question of whether FST and fecal indicator monitoring is the best approach to regulate water quality and protect human health. Many FST methods have only been tested against sewage or fecal samples or isolates in laboratory studies (proof of concept testing) and/or applied in field studies where the “real” answer is not known, so their comparative performance and accuracy cannot be assessed. For FST to be

  19. On the Performance of X-ray Imaging Plates in Gamma Radiography employing Reactor-produced Radioisotopes

    Science.gov (United States)

    Silvani, Maria Ines; de Almeida, Gevaldo L.; Furieri, Rosanne C.; Lopes, Ricardo T.

    2011-08-01

    Gamma-radiography employing radiographic films is a well established technique for non-destructive assays. The advent of X-ray sensitive Imaging Plates opens up new possibilities to apply this technique thanks to the advantages exhibited by this new device. Indeed, besides a sensitivity about 20 times higher then the conventional photographic film, requiring thus a shorter exposure time, it does not require a dark room for a cumbersome and time-consuming chemical processing associated to the development, an can be erased to be reused many times. Moreover, its development carried out by means of a laser beam produces digitalized images which can be promptly stored in a computer. Although its resolution is still poorer than that of the conventional film, those advantages overwhelms this specific parameter when it is not an essential feature for the intended application. This work evaluates the feasibility of employing X-ray Imaging Plates as detector for higher photon energies as those emitted by reactor-produced radioisotopes. Within this frame, radioisotopes such as 198Au and 56Mn, produced at the Argonauta research reactor in the Instituto de Engenharia Nuclear-CNEN have been employed as sources to acquire radiographic images of several pieces of equipment, devices and components. In order to keep the source appearance—with regard to the detector—as punctual as possible, reducing hence the penumbra effect, the mass of the irradiated material had to be limited. Therefore, due to the low neutron flux available at the main port of the reactor, the exposure times have to be extended along several hours or even a couple of days in order to reach an image with adequate contrast. This demand, nevertheless, does not constitute a serious hindrance as the exposure process can be carried out without any intervention or surveillance. Results have shown that in spite of the higher photon energies used, surpassing the X-ray range for which the imaging plates have been

  20. Development of a “Current Energy Mix Scenario” and a “Electricity as Main Energy Source Scenario” for electricity demand up to 2100

    Directory of Open Access Journals (Sweden)

    Mário J. S. Brito

    2014-06-01

    Full Text Available In this work, we develop a model to forecast world electricity production up to 2100. We analyze historical data for electricity production, population and GDP per Capita for the period 1900–2008. We show that electricity production follows general trends. First, there is an electricity intensity target of 0.20-0.25 kWh per unit of GDP (US$2012 as economies mature, except in countries traditionally relying heavily on renewable electricity (hydroelectricity, for whom this target ranges between 0.50 to 0.80 kWh per unit GDP. Also, countries that belong to the same region tend to follow the evolution of electricity production and GDP/Capita of a regional “modelcountry”. Equations that describe the behavior of these model countries are used to forecast electricity production per capita up to 2100 under a low and a high scenario for the evolution of GDP per Capita. For electricity production two main scenarios were set: “Current Energy MixScenario” and “Electricity as Main Energy Source Scenario”, with two additional sub scenarios considering slightly different electric intensities. Forecasts up to 2100 yield a demand forelectricity production 3.5 to 5 times higher than the current production for the “Current EnergyMix Scenario” and about 9 to 14 times for the “Electricity as Main Energy Source Scenario”. Forecasts for the “Current Energy Mix Scenario” matched well with forecasts from IEA/EIA (International Energy Agency/ Energy Information Administration while the forecasts for the“Electricity as the Main Energy Source Scenario” are much higher than current predictions.

  1. Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.

    Science.gov (United States)

    Huang, Binbin; Lei, Chao; Wei, Chaohai; Zeng, Guangming

    2014-10-01

    Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Application of Extended Smoluchowski Equations to Formation of Silver Nanoclusters Generated by Direct Current Magnetron Sputtering Source

    Science.gov (United States)

    Zhang, Chuhang; Feng, Yuanxin

    2016-09-01

    We apply the extended Smoluchowski rate equations with neutralization process between nanocluster (NC) anion and cation to study the formation of silver NCs generated by direct current magnetron sputtering (DC-MSP). By comparing the experimental and simulation results, it was found that the origin of size tuning by the cell length was prolonged aggregation time. Size tuning by DC power (P) was attributed to the enhanced initial number density and ionization fraction of the sputtered materials. It was revealed that parts of NC ions were "lost" after aggregation and the amount of lost ions increased with power (20 W equations are capable to describe the NC formation in gas phase.

  3. Pre-earthquake signals – Part I: Deviatoric stresses turn rocks into a source of electric currents

    Directory of Open Access Journals (Sweden)

    F. T. Freund

    2007-09-01

    Full Text Available Earthquakes are feared because they often strike so suddenly. Yet, there are innumerable reports of pre-earthquake signals. Widespread disagreement exists in the geoscience community how these signals can be generated in the Earth's crust and whether they are early warning signs, related to the build-up of tectonic stresses before major seismic events. Progress in understanding and eventually using these signals has been slow because the underlying physical process or processes are basically not understood. This has changed with the discovery that, when igneous or high-grade metamorphic rocks are subjected to deviatoric stress, dormant electronic charge carriers are activated: electrons and defect electrons. The activation increases the number density of mobile charge carriers in the rocks and, hence, their electric conductivity. The defect electrons are associated with the oxygen anion sublattice and are known as positive holes or pholes for short. The boundary between stressed and unstressed rock acts a potential barrier that lets pholes pass but blocks electrons. Therefore, like electrons and ions in an electrochemical battery, the stress-activated electrons and pholes in the "rock battery" have to flow out in different directions. When the circuit is closed, the battery currents can flow. The discovery of such stress-activated currents in crustal rocks has far-reaching implications for understanding pre-earthquake signals.

  4. REDISCOVERING MISES-HAYEK MONETARY AND BUSINESS CYCLE THEORY IN LIGHT OF THE CURRENT CRISIS: CREDIT EXPANSION AS A SOURCE OF ECONOMIC BOOM AND BUST

    Directory of Open Access Journals (Sweden)

    Marcin Mrowiec

    2013-10-01

    Full Text Available The article starts with a brief description of Mises’ monetary theory, with emphasis on the Misesian differentiation of two kinds of credit: commodity and circulation credit, and with the description of the impact of circulation credit expansion on the business cycle. Further on it is described how Mises’ insights constituted the kernel of Austrian Business Cycle Theory, and how the same observations on the nature of credit constituted the kernel of the Chicago Plan (though Mises’ views on the nature of credit led him to different conculsions than it led the authors of the Chicago Plan, and how this plan is being “rediscovered” now. The following sections deal with observations of one of the preeminent current macroeconomic researches, Mr. Claudio Borio, on the elasticity of credit as the source of the current crisis, and on the importance of the financial cycle in analysing the current economic crisis. The author of this text demonstrates that Austrian Business Cycle Theory gave the same answer regarding the sources of economic crises that now modern macroeconomic theory seems to be approaching, and that the postulates for successful financial cycle modeling are already included in the ABCT. Finally, some observations on the current crisis, as well as proposals of avenues of further research are proposed.

  5. Radiant{trademark} Liquid Radioisotope Intravascular Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Eigler, N.; Whiting, J.; Chernomorsky, A.; Jackson, J.; Knapp, F.F., Jr.; Litvack, F.

    1998-01-16

    RADIANT{trademark} is manufactured by United States Surgical Corporation, Vascular Therapies Division, (formerly Progressive Angioplasty Systems). The system comprises a liquid {beta}-radiation source, a shielded isolation/transfer device (ISAT), modified over-the-wire or rapid exchange delivery balloons, and accessory kits. The liquid {beta}-source is Rhenium-188 in the form of sodium perrhenate (NaReO{sub 4}), Rhenium-188 is primarily a {beta}-emitter with a physical half-life of 17.0 hours. The maximum energy of the {beta}-particles is 2.1 MeV. The source is produced daily in the nuclear pharmacy hot lab by eluting a Tungsten-188/Rhenium-188 generator manufactured by Oak Ridge National Laboratory (ORNL). Using anion exchange columns and Millipore filters the effluent is concentrated to approximately 100 mCi/ml, calibrated, and loaded into the (ISAT) which is subsequently transported to the cardiac catheterization laboratory. The delivery catheters are modified Champion{trademark} over-the-wire, and TNT{trademark} rapid exchange stent delivery balloons. These balloons have thickened polyethylene walls to augment puncture resistance; dual radio-opaque markers and specially configured connectors.

  6. High-performance control of a three-phase voltage-source converter including feedforward compensation of the estimated load current

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Andres E.; Solsona, Jorge A.; Busada, Claudio; Chiacchiarini, Hector [Instituto de Investigaciones en Ingenieria Electrica (IIIE) UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, Bahia Blanca 8000 (Argentina); Valla, Maria Ines [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI) and CONICET, Facultad de Ingenieria, Universidad Nacional de La Plata, La Plata 1900 (Argentina)

    2009-08-15

    In this paper a new control strategy for voltage-source converters (VSC) is introduced. The proposed strategy consists of a nonlinear feedback controller based on feedback linearization plus a feedforward compensation of the estimated load current. In our proposal an energy function and the direct-axis current are considered as outputs, in order to avoid the internal dynamics. In this way, a full linearization is obtained via nonlinear transformation and feedback. An estimate of the load current is feedforwarded to improve the performance of the whole system and to diminish the capacitor size. This estimation allows to obtain a more rugged and cheaper implementation. The estimate is calculated by using a nonlinear reduced-order observer. The proposal is validated through different tests. These tests include performance in presence of switching frequency, measurement filters delays, parameters uncertainties and disturbances in the input voltage. (author)

  7. Quantitative EEG and Current Source Density Analysis of Combined Antiepileptic Drugs and Dopaminergic Agents in Genetic Epilepsy: Two Case Studies.

    Science.gov (United States)

    Emory, Hamlin; Wells, Christopher; Mizrahi, Neptune

    2015-07-01

    Two adolescent females with absence epilepsy were classified, one as attention deficit and the other as bipolar disorder. Physical and cognitive exams identified hypotension, bradycardia, and cognitive dysfunction. Their initial electroencephalograms (EEGs) were considered slightly slow, but within normal limits. Quantitative EEG (QEEG) data included relative theta excess and low alpha mean frequencies. A combined treatment of antiepileptic drugs with a catecholamine agonist/reuptake inhibitor was sequentially used. Both patients' physical and cognitive functions improved and they have remained seizure free. The clinical outcomes were correlated with statistically significant changes in QEEG measures toward normal Z-scores in both anterior and posterior regions. In addition, low resolution electromagnetic tomography (LORETA) Z-scored source correlation analyses of the initial and treated QEEG data showed normalized patterns, supporting a neuroanatomic resolution. This study presents preliminary evidence for a neurophysiologic approach to patients with absence epilepsy and comorbid disorders and may provide a method for further research. © EEG and Clinical Neuroscience Society (ECNS) 2014.

  8. Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

    Energy Technology Data Exchange (ETDEWEB)

    Schock, A.; Mukunda, M.; Or, T.; Kumar, V.; Summers, G.

    1994-02-14

    The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator (RTPV), to complement similar studies of Radioisotope Thermoelectric Generators (RTGs) and Stirling Generators (RSGs) previously published by the author. Instead of conducting a generic study, it was decided to focus the design effort by directing it at a specific illustrative space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a post-encounter cruise lasting up to one year.

  9. Light weight radioisotope heater unit (LWRHU): a technical description of the reference design

    Energy Technology Data Exchange (ETDEWEB)

    Tate, R.E.

    1982-01-01

    The Light Weight Radioisotope Heater Unit (LWRHU), a new radioisotope heater unit for use in space missions, is a /sup 238/PuO/sub 2/-fueled unit designed to provide a thermal watt in dispersed locations on a spacecraft. The LWRHU is required to maintain the temperature of a component at a level where the component will function reliably in space. Two major constraints are placed on the unit's design; it must be as light as possible and must provide enough protection to immobilize the plutonium fuel to the maximum extent in all phases of the unit's lifetime. The four components are pelletized fuel, platinum-alloy encapsulation, pyrolytic graphite thermal insulation, and high-technology graphite ablation shell. The LWRHU is a cylinder 32 mm (1.26 in.) high and 26 mm (1.02 in.) in diameter. It weighs slightly less than 40 g(.09 lb).

  10. Modelling study on production cross sections of {sup 111}In radioisotopes used in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Kara, Ayhan; Korkut, Turgay [Sinop Univ. (Turkey). Faculty of Engineering; Yigit, Mustafa [Aksaray Univ. (Turkey). Faculty of Science and Arts; Tel, Eyyup [Osmaniye Korkut Ata Univ. (Turkey). Faculty of Science and Arts

    2015-07-15

    Radiopharmaceuticals are radioactive drugs used for diagnosis or treatment in a tracer quantity with no pharmacological action. The production of radiopharmaceuticals is carried out in the special research centers generally using by the cyclotron systems. Indium-111 is one of the most useful radioisotopes used in nuclear medicine. In this paper, we calculated the production cross sections of {sup 111}In radioisotope via {sup 111-114}Cd(p,xn) nuclear reactions up to 60 MeV energy. In the model calculations, ALICE/ASH, TALYS 1.6 and EMPIRE 3.2 Malta nuclear reaction code systems were used. The model calculation results were compared to the experimental literature data and TENDL-2014 (TALYS-based) data.

  11. Evaluation of radiation dose for registered users of radioisotopes at Faculty of Engineering, Hiroshima University

    Energy Technology Data Exchange (ETDEWEB)

    Shizuma, Kiyoshi; Iwatani, Kazuo; Hasai, Hiromi (Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Engineering)

    1993-12-01

    The effective dose equivalent for registered users of radioisotopes was evaluated. The external dose was evaluated from the dose measured with the film badge. The internal dose was evaluated on the basis of the concentration of radioisotopes in air, which is calculated beforehand for each facility. The radon concentration in air was measured for all facilities. The contribution of radon daughters to the internal dose was added for users of accelerator and electron microscope of radioactive samples. The maximum effective dose was 0.22 mSv among 97 users in 1992 and the dominant dose was 0.1-0.01 mSv. Present evaluation is important for individual radiation hazard control and also for fundamental data for abbreviation of health examination of users. (author).

  12. Investigation of the Influence of Magnetospheric Sources of Field-Aligned Currents on the Equatorial Electric Fields

    Science.gov (United States)

    Beloushko, Konstantin; Knyazeva, Mariya

    The urgency of studying electrodynamic processes related to the influence of spatial and temporal heterogeneities of the electromagnetic field in the Earth's upper atmosphere to the functioning of modern technological systems , satellite navigation systems , radio propagation Fundamentally new is the use of various third-party electrodynamic models in the total open loop model of the atmosphere based on the Upper Atmosphere Model (UAM) [1,2]. Performing calculations on model UAM using different spatial and temporal distributions of field-aligned currents and brands Lukianova and Papitashvili. A comparison of model results with data Jicamarca Incoherent Scatter Radar (Peru). References Namgaladze A.A., Korenkov Yu.N., Klimenko V.V., Karpov I.V., Bessarab F.S., Surotkin V.A., Gluschenko T.A., Naumova N.M. Global model of the thermosphere-ionosphere-protonosphere system. Pure and Applied Geophysics. No.2/3, 127, 219-254, 1988. Namgaladze A.A., Martynenko O.V., Namgaladze A.N. Global model of the upper atmosphere with variable latitudinal steps of numerical integration, IUGG XXI General Assembly, Boulder, 1995, Abstracts, GAB41F-6, B150, 1995, and (in Russian) Geamagn. Aeron., 36, 89-95, 1996a.

  13. Using radioisotope method for measuring ice layer thickness in pulp lines

    Science.gov (United States)

    Malarev, V. I.; Kopteva, A. V.

    2017-10-01

    Operating hydro-transportation systems in Russia means challenges resulting from ice formation within pipelines when idle, and even during actual operation, thus some protection of pulp lines against freezing is a must. This work is devoted to the radioisotope method for ice layer thickness measuring on pipeline walls, which is now more and more often used in practice. This is a low cost method with units and parts easily replaceable, simple by design, non-interrupting the process.

  14. COMPASS Final Report: Radioisotope Electric Propulsion (REP) Centaur Orbiter New Frontiers Mission

    Science.gov (United States)

    Oleson, Steven R.; McGuire, Melissa L.

    2011-01-01

    Radioisotope Electric Propulsion (REP) has been shown in past studies to enable missions to outer planetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass Radioisotope Power System (RPS) and light spacecraft (S/C) components. In order to determine the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers (NF) cost cap. The design shows that an orbiter using several long lived (approx.200 kg xenon (Xe) throughput), low power (approx.700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the NF cost cap. Optimal specific impulses (Isp) for the Hall thrusters were found to be around 2000 s with thruster efficiencies over 40 percent. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be used to enhance science and simplify communications. The mission design detailed in this report is a Radioisotope Power System (RPS) powered EP science orbiter to the Centaur Thereus with arrival 10 yr after launch, ending in a 1 yr science mapping mission. Along the trajectory, approximately 1.5 yr into the mission, the REP S/C does a flyby of the Trojan asteroid Tlepolemus. The total (Delta)V of the trajectory is 8.9 km/s. The REP S/C is delivered to orbit on an Atlas 551 class launch vehicle with a Star 48 B solid rocket stage

  15. Simple radio-isotopic method for the detection of bronchial inhalation during intensive care

    Energy Technology Data Exchange (ETDEWEB)

    Venot, J.; Veyriras, E.; Vandroux, J.C.; Bournaud, E.; Gastinne, H.; Beck, C.

    1984-08-01

    The high incidence of pneumopathy in intensive care units might be due to the pulmonary aspiration of gastric juice following gastro-oesophageal reflux. The paper describes a radio-isotopic method using material easy to install at the patient's bedside. This technique demonstrated aspiration of gastric juice in the lungs of 8 of 25 intensive care patients investigated. Such a method might be useful later to demonstrate that silent bronchial aspirations of gastric juice are responsible for pulmonary complications.

  16. submitter Development of a Superconducting Magnet for a Compact Cyclotron for Radioisotope Production

    CERN Document Server

    Garcia-Tabares, Luis; Calero, Jesus; Gutierrez, Jose L; Munilla, Javier; Obradors, Diego; Perez, Jose M; Toral, Fernando; Iturbe, Rafael; Minguez, Leire; Gomez, Jose; Rodilla, Elena; Bajko, Marta; Michels, Matthias; Berkowitz, Daniel; Haug, Friedrich

    2016-01-01

    The present paper describes the development process of a low critical temperature superconducting magnet to be installed in a compact cyclotron producing single-dose radioisotopes for clinical and preclinical applications. After a brief description of the accelerator, the magnet development process is described, starting from the magnetic, mechanical, quench, and thermal calculations, continuing with the designing process, particularly the support structure of the magnet and the cryogenic supply system, to finish with the fabrication and the first tests than have been performed.

  17. Quantifying the Earthquake Clustering that Independent Sources with Stationary Rates (as Included in Current Risk Models) Can Produce.

    Science.gov (United States)

    Fitzenz, D. D.; Nyst, M.; Apel, E. V.; Muir-Wood, R.

    2014-12-01

    The recent Canterbury earthquake sequence (CES) renewed public and academic awareness concerning the clustered nature of seismicity. Multiple event occurrence in short time and space intervals is reminiscent of aftershock sequences, but aftershock is a statistical definition, not a label one can give an earthquake in real-time. Aftershocks are defined collectively as what creates the Omori event rate decay after a large event or are defined as what is taken away as "dependent events" using a declustering method. It is noteworthy that depending on the declustering method used on the Canterbury earthquake sequence, the number of independent events varies a lot. This lack of unambiguous definition of aftershocks leads to the need to investigate the amount of clustering inherent in "declustered" risk models. This is the task we concentrate on in this contribution. We start from a background source model for the Canterbury region, in which 1) centroids of events of given magnitude are distributed using a latin-hypercube lattice, 2) following the range of preferential orientations determined from stress maps and focal mechanism, 3) with length determined using the local scaling relationship and 4) rates from a and b values derived from the declustered pre-2010 catalog. We then proceed to create tens of thousands of realizations of 6 to 20 year periods, and we define criteria to identify which successions of events in the region would be perceived as a sequence. Note that the spatial clustering expected is a lower end compared to a fully uniform distribution of events. Then we perform the same exercise with rates and b-values determined from the catalog including the CES. If the pre-2010 catalog was long (or rich) enough, then the computed "stationary" rates calculated from it would include the CES declustered events (by construction, regardless of the physical meaning of or relationship between those events). In regions of low seismicity rate (e.g., Canterbury before

  18. Radioisotope labelling of several major insect pest. Dipping the pupae in /sup 32/P solution

    Energy Technology Data Exchange (ETDEWEB)

    Sutrisno, S. (National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre)

    1981-12-01

    Radioisotope uptake by insects could take place through various parts i.e. mouth, cuticula, intersegmental, secretion and excretion organs. Usually insects are labelled internally by feeding them on an artificial diet containing radioisotope solution. Labelling of several insect pests of cabbage (Crocidolomia binotalis) Zell and Plutella maculipennis Curt and rice (Chilo suppressalis Walker) by dipping of the pupae in /sup 32/P solution showed a promising result. Pupae of Crocidolomia binotalis Zell dipped in 3 ml solution of /sup 32/P with specific activities of 1, 3, 5 and 7 ..mu..Ci/ml had developed labelled adults of sufficiently high radioactivity levels for ecological studies. Similar results were also obtained with Plutella maculipennis Curt and Chilo suppressalis Walker with doses of 1, 3, 5, 7 and 9 ..mu..Ci/ml /sup 32/P solution. The best doses for radioisotope labelling by dipping of the insects Crocidolomia binotalis Zell, Plutella maculipennis Curt, and Chilo suppressalis Walker were 1, 9, and 7 ..mu..Ci/ml respectivelly.

  19. Test Program for Stirling Radioisotope Generator Hardware at NASA Glenn Research Center

    Science.gov (United States)

    Lewandowski, Edward J.; Bolotin, Gary S.; Oriti, Salvatore M.

    2015-01-01

    Stirling-based energy conversion technology has demonstrated the potential of high efficiency and low mass power systems for future space missions. This capability is beneficial, if not essential, to making certain deep space missions possible. Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG), a 140-W radioisotope power system. A variety of flight-like hardware, including Stirling convertors, controllers, and housings, was designed and built under the ASRG flight development project. To support future Stirling-based power system development NASA has proposals that, if funded, will allow this hardware to go on test at the NASA Glenn Research Center. While future flight hardware may not be identical to the hardware developed under the ASRG flight development project, many components will likely be similar, and system architectures may have heritage to ASRG. Thus, the importance of testing the ASRG hardware to the development of future Stirling-based power systems cannot be understated. This proposed testing will include performance testing, extended operation to establish an extensive reliability database, and characterization testing to quantify subsystem and system performance and better understand system interfaces. This paper details this proposed test program for Stirling radioisotope generator hardware at NASA Glenn. It explains the rationale behind the proposed tests and how these tests will meet the stated objectives.

  20. NASA Glenn Research Center Support of the Advanced Stirling Radioisotope Generator Project

    Science.gov (United States)

    Wilson, Scott D.; Wong, Wayne A.

    2015-01-01

    A high-efficiency radioisotope power system was being developed for long-duration NASA space science missions. The U.S. Department of Energy (DOE) managed a flight contract with Lockheed Martin Space Systems Company to build Advanced Stirling Radioisotope Generators (ASRGs), with support from NASA Glenn Research Center. DOE initiated termination of that contract in late 2013, primarily due to budget constraints. Sunpower, Inc., held two parallel contracts to produce Advanced Stirling Convertors (ASCs), one with Lockheed Martin to produce ASC-F flight units, and one with Glenn for the production of ASC-E3 engineering unit "pathfinders" that are built to the flight design. In support of those contracts, Glenn provided testing, materials expertise, Government-furnished equipment, inspection capabilities, and related data products to Lockheed Martin and Sunpower. The technical support included material evaluations, component tests, convertor characterization, and technology transfer. Material evaluations and component tests were performed on various ASC components in order to assess potential life-limiting mechanisms and provide data for reliability models. Convertor level tests were conducted to characterize performance under operating conditions that are representative of various mission conditions. Despite termination of the ASRG flight development contract, NASA continues to recognize the importance of high-efficiency ASC power conversion for Radioisotope Power Systems (RPS) and continues investment in the technology, including the continuation of the ASC-E3 contract. This paper describes key Government support for the ASRG project and future tests to be used to provide data for ongoing reliability assessments.

  1. Medical Radioisotope Production in a Power-Flattened ADS Fuelled with Uranium and Plutonium Dioxides

    Directory of Open Access Journals (Sweden)

    Gizem Bakır

    2016-01-01

    Full Text Available This study presents the medical radioisotope production performance of a conceptual accelerator driven system (ADS. Lead-bismuth eutectic (LBE is selected as target material. The subcritical fuel core is conceptually divided into ten equidistant subzones. The ceramic (natural U, PuO2 fuel mixture and the materials used for radioisotope production (copper, gold, cobalt, holmium, rhenium, thulium, mercury, palladium, thallium, molybdenum, and yttrium are separately prepared as cylindrical rods cladded with carbon/carbon composite (C/C and these rods are located in the subzones. In order to obtain the flattened power density, percentages of PuO2 in the mixture of UO2 and PuO2 in the subzones are adjusted in radial direction of the fuel zone. Time-dependent calculations are performed at 1000 MW thermal fission power (Pth for one hour using the BURN card. The neutronic results show that the investigated ADS has a high neutronic capability, in terms of medical radioisotope productions, spent fuel transmutation and energy multiplication. Moreover, a good quasiuniform power density is achieved in each material case. The peak-to-average fission power density ratio is in the range of 1.02–1.28.

  2. Technical Reviews on the Radioisotope Application for Leak Detection in Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Seop; Jung, Sung Hee; Kim, Jong Bum; Kim, Jae Ho

    2006-02-15

    The previous techniques on the detection of leaks from reservoirs are difficult to identify the leak points and leak pathways in reservoirs. Additionally the complexity and ambiguity of data analysis resulted from them can increase the failures of leak detection. While, The technique using radioisotope as a tracer is considered to be very promising. In the same context, systematic studies led by IAEA are being practiced by organizing the task force team. The detection technique using natural tracer can give information about the age of ground water and the interconnection between ground water and reservoir water and the seepage origin. On the other hand, the one using artificial tracer can identify the leak point in reservoirs directly, in which radioactive cloud migration method and radioactive tracer adsorption method are included. The former is using hydrophilic radioisotope tracer, and the latter adsorptive radioisotope tracer which is emitting gamma ray. The radiotracer are injected at a point of the reservoir near to the bottom. Afterwards, the migration of the radioactive tracer is followed by means of submerged scintillation detectors suspended from boats. Usually {sup 131}I, {sup 82}Br, {sup 46}Sc, and {sup 198}Au etc. can be used as tracer. The point reaching the maximum concentration of tracer corresponds to the leak point in reservoirs.

  3. The copper radioisotopes: a systematic review with special interest to 64Cu.

    Science.gov (United States)

    Niccoli Asabella, Artor; Cascini, Giuseppe Lucio; Altini, Corinna; Paparella, Domenico; Notaristefano, Antonio; Rubini, Giuseppe

    2014-01-01

    Copper (Cu) is an important trace element in humans; it plays a role as a cofactor for numerous enzymes and other proteins crucial for respiration, iron transport, metabolism, cell growth, and hemostasis. Natural copper comprises two stable isotopes, (63)Cu and (65)Cu, and 5 principal radioisotopes for molecular imaging applications ((60)Cu, (61)Cu, (62)Cu, and (64)Cu) and in vivo targeted radiation therapy ((64)Cu and (67)Cu). The two potential ways to produce Cu radioisotopes concern the use of the cyclotron or the reactor. A noncopper target is used to produce noncarrier-added Cu thanks to a chemical separation from the target material using ion exchange chromatography achieving a high amount of radioactivity with the lowest possible amount of nonradioactive isotopes. In recent years, Cu isotopes have been linked to antibodies, proteins, peptides, and nanoparticles for preclinical and clinical research; pathological conditions that influence Cu metabolism such as Menkes syndrome, Wilson disease, inflammation, tumor growth, metastasis, angiogenesis, and drug resistance have been studied. We aim to discuss all Cu radioisotopes application focusing on (64)Cu and in particular its form (64)CuCl2 that seems to be the most promising for its half-life, radiation emissions, and stability with chelators, allowing several applications in oncological and nononcological fields.

  4. The Copper Radioisotopes: A Systematic Review with Special Interest to 64Cu

    Directory of Open Access Journals (Sweden)

    Artor Niccoli Asabella

    2014-01-01

    Full Text Available Copper (Cu is an important trace element in humans; it plays a role as a cofactor for numerous enzymes and other proteins crucial for respiration, iron transport, metabolism, cell growth, and hemostasis. Natural copper comprises two stable isotopes, 63Cu and 65Cu, and 5 principal radioisotopes for molecular imaging applications (60Cu, 61Cu, 62Cu, and 64Cu and in vivo targeted radiation therapy (64Cu and 67Cu. The two potential ways to produce Cu radioisotopes concern the use of the cyclotron or the reactor. A noncopper target is used to produce noncarrier-added Cu thanks to a chemical separation from the target material using ion exchange chromatography achieving a high amount of radioactivity with the lowest possible amount of nonradioactive isotopes. In recent years, Cu isotopes have been linked to antibodies, proteins, peptides, and nanoparticles for preclinical and clinical research; pathological conditions that influence Cu metabolism such as Menkes syndrome, Wilson disease, inflammation, tumor growth, metastasis, angiogenesis, and drug resistance have been studied. We aim to discuss all Cu radioisotopes application focusing on 64Cu and in particular its form 64CuCl2 that seems to be the most promising for its half-life, radiation emissions, and stability with chelators, allowing several applications in oncological and nononcological fields.

  5. Dose rate of restroon in facilities using radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Gwi [Dept. of uclear Medicine, Inha University hospital, Incheon (Korea, Republic of); An, Seong Min [Dept. of Radiology, Gachon University, Incheon (Korea, Republic of)

    2016-06-15

    This study is therefore aimed at measuring the surface dose rate and the spatial dose rate in and outside the radionuclide facility in order to ensure safety of the patients, radiation workers and family care-givers in their use of such equipment and to provide a basic framework for further research on radiation protection. The study was conducted at 4 restrooms in and outside the radionuclide facility of a general hospital in Incheon between May 1 and July 31, 2014. During the study period, the spatial contamination dose rate and the surface contamination dose rate before and after radiation use were measured at the 4 places−thyroid therapy room, PET center, gamma camera room, and outpatient department. According to the restroom use survey by hospitals, restrooms in the radionuclide facility were used not only by patients but also by family care-givers and some of radiation workers. The highest cumulative spatial radiation dose rate was 8.86 mSv/hr at camera room restroom, followed by 7.31 mSv/hr at radioactive iodine therapy room restroom, 2.29 mSv/hr at PET center restroom, and 0.26 mSv/hr at outpatient department restroom, respectively. The surface radiation dose rate measured before and after radiation use was the highest at toilets, which are in direct contact with patient's excretion, followed by the center and the entrance of restrooms. Unsealed radioactive sources used in nuclear medicine are relatively safe due to short half lives and low energy. A patient who received those radioactive sources, however, may become a mobile radioactive source and contaminate areas the patient contacts−camera room, sedation room, and restroom−through secretion and excretion. Therefore, patients administered radionuclides should be advised to drink sufficient amounts of water to efficiently minimize radiation exposure to others by reducing the biological half-life, and members of the public−family care-givers, pregnant women, and children−be as far away from

  6. Polar conic current sheets as sources and channels of energetic particles in the high-latitude heliosphere

    Science.gov (United States)

    Khabarova, Olga; Malova, Helmi; Kislov, Roman; Zelenyi, Lev; Obridko, Vladimir; Kharshiladze, Alexander; Tokumaru, Munetoshi; Sokół, Justyna; Grzedzielski, Stan; Fujiki, Ken'ichi; Malandraki, Olga

    2017-04-01

    The existence of a large-scale magnetically separated conic region inside the polar coronal hole has been predicted by the Fisk-Parker hybrid heliospheric magnetic field model in the modification of Burger and co-workers (Burger et al., ApJ, 2008). Recently, long-lived conic (or cylindrical) current sheets (CCSs) have been found from Ulysses observations at high heliolatitudes (Khabarova et al., ApJ, 2017). The characteristic scale of these structures is several times lesser than the typical width of coronal holes, and the CCSs can be observed at 2-3 AU for several months. CCS crossings in 1994 and 2007 are characterized by sharp decreases in the solar wind speed and plasma beta typical for predicted profiles of CCSs. In 2007, a CCS was detected directly over the South Pole and strongly highlighted by the interaction with comet McNaught. The finding is confirmed by restorations of solar coronal magnetic field lines that reveal the occurrence of conic-like magnetic separators over the solar poles both in 1994 and 2007. Interplanetary scintillation data analysis also confirms the existence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. The occurrence of long-lived CCSs in the high-latitude solar wind could shed light on how energetic particles reach high latitudes. Energetic particle enhancements up to tens MeV were observed by Ulysses at edges of CCSs both in 1994 and 2007. In 1994 this effect was clearer, probably due to technical reasons. Accelerated particles could be produced either by magnetic reconnection at the edges of a CCS in the solar corona or in the solar wind. We discuss the role of high-latitude CCSs in propagation of energetic particles in the heliosphere and revisit previous studies of energetic particle enhancements at high heliolatitudes. We also suggest that the existence of a CCS can modify the distribution of the solar wind as a function of heliolatitude and consequently impact ionization

  7. Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes.

    Science.gov (United States)

    Li, Zhuguo; Ohnuki, Toshihiko; Ikeda, Ko

    2016-07-28

    Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). Two varieties of alkaline liquors were used in the PS-ash based geopolymers, corresponding to aqueous Na-metasilicate and Na-disilicate compositions. PS-ashes were found to be semi-crystalline and to have porous structures that make it possible to absorb much liquor. Flexural strengths of PS-ash-based geopolymers with liquor/filler ratios (L/F) of 1.0-1.5 ranged from 0.82 to 1.51 MPa at 4 weeks age, depending on PS-ashes and liquors used. The reaction process of the constituent minerals of the PS-ash is discussed. Furthermore, we attempted to solidify hazardous water contaminated with radioisotopes. Non-radioactive strontium and cesium nitrates were added as surrogates at a dosage of 1% into the PS-ash-based geopolymers. Generally, high immobilization ratios up to 99.89% and 98.77% were achieved for Sr(2+) and Cs⁺, respectively, depending on the source of PS-ashes, alkaline liquors, and material ages. However, in some cases, poor immobilization ratios were encountered, and we further discussed the causes of the instability of derived geopolymer gels on the basis of XANES spectra.

  8. Lunar Surface Stirling Power Systems Using Isotope Heat Sources

    Science.gov (United States)

    Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

    2010-01-01

    For many years, NASA has used the decay of plutonium-238 (Pu-238) (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTGs), which have provided electrical power for many NASA missions. While RTGs have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency and the scarcity of plutonium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14.75 Earth days), isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 W with two GPHS modules at the beginning of life (BOL) (32% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a four-fold reduction in the number of GPHS modules. This study considers the use of americium-241 (Am-241) as a substitute for the Pu-238 in Stirling- convertor-based Radioisotope Power Systems (RPS) for power levels from tens of watts to 5 kWe. The Am-241 is used as a substitute for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about one-fifth while maintaining approximately the same system mass. In order to obtain the nominal 160 W of electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot

  9. Pacific Proving Grounds radioisotope imprint in the Philippine Sea sediments.

    Science.gov (United States)

    Pittauer, Daniela; Roos, Per; Qiao, Jixin; Geibert, Walter; Elvert, Marcus; Fischer, Helmut W

    2018-06-01

    Radionuclide concentrations were studied in sediment cores taken at the continental slope of the Philippine Sea off Mindanao Island in the equatorial Western Pacific. High resolution deposition records of anthropogenic radionuclides were collected at this site. Excess 210 Pb together with excess 228 Th and anthropogenic radionuclides provided information about accumulation rates. Concentrations of Am and Pu isotopes were detected by gamma spectrometry, alpha spectrometry and ICP-MS. The Pu ratios indicate a high portion (minimum of 60%) of Pu from the Pacific Proving Grounds (PPG). This implies that the transport of PPG derived plutonium with the Mindanao Current southward is similarly effective as the previously known transport towards the north with the Kuroshio Current. The record is compared to other studies from northwest Pacific marginal seas and Lombok basin in the Indonesian Archipelago. The sediment core top was found to contain a 6 cm thick layer dominated by terrestrial organic matter, which was interpreted as a result of the 2012 Typhoon Pablo-related fast deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. A Power Regulation and Droop Mode Control Method for a Stand-Alone Load Fed from a PV-Current Source Inverter

    Science.gov (United States)

    Khayamy, Mehdy; Ojo, Olorunfemi

    2015-04-01

    A current source inverter fed from photovoltaic cells is proposed to power an autonomous load when operating under either power regulation or voltage and frequency drooping modes. Input-output linearization technique is applied to the overall nonlinear system to achieve a globally stable system under feasible operating conditions. After obtaining the steady-state model that demarcates the modes of operation, computer Simulation results for variations in irradiance and the load power of the controlled system are generated in which an acceptable dynamic response of the power generator system under the two modes of operation is observed.

  11. Initial Beam Dynamics Simulations of a High-Average-Current Field-Emission Electron Source in a Superconducting RadioFrequency Gun

    Energy Technology Data Exchange (ETDEWEB)

    Mohsen, O. [Northern Illinois U.; Gonin, I. [Fermilab; Kephart, R. [Fermilab; Khabiboulline, T. [Fermilab; Piot, P. [Northern Illinois U.; Solyak, N. [Fermilab; Thangaraj, J. C. [Fermilab; Yakovlev, V. [Fermilab

    2018-01-05

    High-power electron beams are sought-after tools in support to a wide array of societal applications. This paper investigates the production of high-power electron beams by combining a high-current field-emission electron source to a superconducting radio-frequency (SRF) cavity. We especially carry out beam-dynamics simulations that demonstrate the viability of the scheme to form $\\sim$ 300 kW average-power electron beam using a 1+1/2-cell SRF gun.

  12. Measurement of ion species in high current ECR H⁺/D⁺ ion source for IFMIF (International Fusion Materials Irradiation Facility).

    Science.gov (United States)

    Shinto, K; Senée, F; Ayala, J-M; Bolzon, B; Chauvin, N; Gobin, R; Ichimiya, R; Ihara, A; Ikeda, Y; Kasugai, A; Kitano, T; Kondo, K; Marqueta, A; Okumura, Y; Takahashi, H; Valette, M

    2016-02-01

    Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H(+)) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D(+)) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H(+) ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H(+)/D(+) ratio estimated by the emittance monitor was more than 90% at those extraction currents.

  13. Measurement of ion species in high current ECR H{sup +}/D{sup +} ion source for IFMIF (International Fusion Materials Irradiation Facility)

    Energy Technology Data Exchange (ETDEWEB)

    Shinto, K., E-mail: shinto.katsuhiro@jaea.go.jp; Ichimiya, R.; Ihara, A.; Ikeda, Y.; Kasugai, A.; Kitano, T.; Kondo, K.; Takahashi, H. [Rokkasho Fusion Institute, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Senée, F.; Bolzon, B.; Chauvin, N.; Gobin, R.; Valette, M. [Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA/Saclay, DSM/IRFU, 91191 Gif/Yvette (France); Ayala, J.-M.; Marqueta, A.; Okumura, Y. [IFMIF/EVEDA Project Team, Rokkasho, Aomori 039-3212 (Japan)

    2016-02-15

    Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H{sup +}) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D{sup +}) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H{sup +} ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H{sup +}/D{sup +} ratio estimated by the emittance monitor was more than 90% at those extraction currents.

  14. Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB

    Science.gov (United States)

    Wang, Xiao-Yen, J.

    2012-01-01

    This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under i) different sink temperatures and ii) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies.

  15. Design and Digital Implementation of Constant Frequency Hysteresis Current Controller for Three-Phase Voltage Source Inverter Using TMS320F2812

    Science.gov (United States)

    Kalyanraj, D.; Lenin Prakash, S.

    2014-01-01

    A constant frequency hysteresis current control technique for a three-phase voltage source inverter (VSI) has been developed for AC drives, power quality and renewable energy applications. This paper presents a digital implementation of a constant frequency hysteresis current control technique for a three-phase VSI feeding an inductive load, using digital signal controller TMS320F2812. The limitations of variable frequency hysteresis control have been discussed and overcoming these limitations by means of digital implementation has been proposed. The complete design procedure of the proposed technique has been presented with an illustrative example. The three-phase VSI feeding an inductive load has also been simulated by using MATLAB and the simulation results have been presented. The hardware results of hysteresis current controlled three-phase VSI feeding an inductive load have been presented. Also the performance analysis of the hysteresis current controller has been presented. Operation of this controller has also been explained with a help of phase plane trajectory of hysteresis controller.

  16. Summary of Stirling Convertor Testing at NASA Glenn Research Center in Support of Stirling Radioisotope Power System Development

    Science.gov (United States)

    Schifer, Nicholas A.; Oriti, Salvatore M.

    2013-01-01

    The NASA Glenn Research Center (GRC) has been testing 100 We class, free-piston Stirling convertors for potential use in Stirling Radioisotope Power Systems (RPS) for space science and exploration missions. Free-piston Stirling convertors are capable of achieving a 38% conversion efficiency, making Stirling attractive for meeting future power system needs in light of the shrinking U.S. plutonium fuel supply. Convertors currently on test include four Stirling Technology Demonstration Convertors (TDCs), manufactured by the Stirling Technology Company (STC), and six Advanced Stirling Convertors (ASCs), manufactured by Sunpower, Inc. Total hours of operation is greater than 514,000 hours (59 years). Several tests have been initiated to demonstrate the functionality of Stirling convertors for space applications, including: in-air extended operation, thermal vacuum extended operation. Other tests have also been conducted to characterize Stirling performance in anticipated mission scenarios. Data collected during testing has been used to support life and reliability estimates, drive design changes and improve quality, and plan for expected mission scenarios. This paper will provide a summary of convertors tested at NASA GRC and discuss lessons learned through extended testing.

  17. A Current Control Approach for an Abnormal Grid Supplied Ultra Sparse Z-Source Matrix Converter with a Particle Swarm Optimization Proportional-Integral Induction Motor Drive Controller

    Directory of Open Access Journals (Sweden)

    Seyed Sina Sebtahmadi

    2016-11-01

    Full Text Available A rotational d-q current control scheme based on a Particle Swarm Optimization- Proportional-Integral (PSO-PI controller, is used to drive an induction motor (IM through an Ultra Sparse Z-source Matrix Converter (USZSMC. To minimize the overall size of the system, the lowest feasible values of Z-source elements are calculated by considering the both timing and aspects of the circuit. A meta-heuristic method is integrated to the control system in order to find optimal coefficient values in a single multimodal problem. Henceforth, the effect of all coefficients in minimizing the total harmonic distortion (THD and balancing the stator current are considered simultaneously. Through changing the reference point of magnitude or frequency, the modulation index can be automatically adjusted and respond to changes without heavy computational cost. The focus of this research is on a reliable and lightweight system with low computational resources. The proposed scheme is validated through both simulation and experimental results.

  18. Estimation of Acoustic Particle Motion and Source Bearing Using a Drifting Hydrophone Array Near a River Current Turbine to Assess Disturbances to Fish

    Science.gov (United States)

    Murphy, Paul G.

    River hydrokinetic turbines may be an economical alternative to traditional energy sources for small communities on Alaskan rivers. However, there is concern that sound from these turbines could affect sockeye salmon (Oncorhynchus nerka), an important resource for small, subsistence based communities, commercial fisherman, and recreational anglers. The hearing sensitivity of sockeye salmon has not been quantified, but behavioral responses to sounds at frequencies less than a few hundred Hertz have been documented for Atlantic salmon (Salmo salar), and particle motion is thought to be the primary mode of stimulation. Methods of measuring acoustic particle motion are well-established, but have rarely been necessary in energetic areas, such as river and tidal current environments. In this study, the acoustic pressure in the vicinity of an operating river current turbine is measured using a freely drifting hydrophone array. Analysis of turbine sound reveals tones that vary in frequency and magnitude with turbine rotation rate, and that may sockeye salmon may sense. In addition to pressure, the vertical components of particle acceleration and velocity are estimated by calculating the finite difference of the pressure signals from the hydrophone array. A method of determining source bearing using an array of hydrophones is explored. The benefits and challenges of deploying drifting hydrophone arrays for marine renewable energy converter monitoring are discussed.

  19. Light-Weight Radioisotope Heater Unit final safety analysis report (LWRHU-FSAR): Volume 1: A. Introduction and executive summary: B. Reference Design Document (RDD)

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.W.

    1988-10-01

    The orbiter and probe portions of the National Aeronautics and Space Administration (NASA) Galileo spacecraft contain components which require auxiliary heat during the mission. To meet these needs, the Department of Energy's (DOE's) Office of Special Applications (OSA) has sponsored the design, fabrication, and testing of a one-watt encapsulated plutonium dioxide-fueled thermal heater named the Light-Weight Radioisotope Heater Unit (LWRHU). This report, prepared by Monsanto Research Corporation (MRC), addresses the radiological risks which might be encountered by people both at the launch area and worldwide should postulated mission failures or malfunctions occur, resulting in the release of the LWRHUs to the environment. Included are data from the design, mission descriptions, postulated accidents with their consequences, test data, and the derived source terms and personnel exposures for the various events. 11 refs., 44 figs., 11 tabs.

  20. Assessment of contamination sources of trace metals in wastewater ...

    African Journals Online (AJOL)

    The distribution and potential contamination sources of trace metals (Fe, Nb, Pb, Rb, Sr, Ti, Y and Zr) in long-term wastewater irrigated garden soils were investigated by using radioisotope excited X-ray fluorescence. The result indicates that the soils have elevated concentration of Fe, Pb, Ti and Y in comparison with mean ...