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%.

Optimization of a near-field thermophotovoltaic system operating at low temperature and large vacuum gap

Science.gov (United States)

Lim, Mikyung; Song, Jaeman; Kim, Jihoon; Lee, Seung S.; Lee, Ikjin; Lee, Bong Jae

2018-05-01

The present work successfully achieves a strong enhancement in performance of a near-field thermophotovoltaic (TPV) system operating at low temperature and large-vacuum-gap width by introducing a hyperbolic-metamaterial (HMM) emitter, multilayered graphene, and an Au-backside reflector. Design variables for the HMM emitter and the multilayered-graphene-covered TPV cell are optimized for maximizing the power output of the near-field TPV system with the genetic algorithm. The near-field TPV system with the optimized configuration results in 24.2 times of enhancement in power output compared with that of the system with a bulk emitter and a bare TPV cell. Through the analysis of the radiative heat transfer together with surface-plasmon-polariton (SPP) dispersion curves, it is found that coupling of SPPs generated from both the HMM emitter and the multilayered-graphene-covered TPV cell plays a key role in a substantial increase in the heat transfer even at a 200-nm vacuum gap. Further, the backside reflector at the bottom of the TPV cell significantly increases not only the conversion efficiency, but also the power output by generating additional polariton modes which can be readily coupled with the existing SPPs of the HMM emitter and the multilayered-graphene-covered TPV cell.

Design and Optimization of Thermophotovoltaic System Cavity with Mirrors

Directory of Open Access Journals (Sweden)

Tian Zhou

2016-09-01

Full Text Available Thermophotovoltaic (TPV systems can convert radiant energy into electrical power. Here we explore the design of the TPV system cavity, which houses the emitter and the photovoltaic (PV cells. Mirrors are utilized in the cavity to modify the spatial and spectral distribution within. After discussing the basic concentric tubular design, two novel cavity configurations are put forward and parametrically studied. The investigated variables include the shape, number, and placement of the mirrors. The optimization objectives are the optimized efficiency and the extended range of application of the TPV system. Through numerical simulations, the relationship between the design parameters and the objectives are revealed. The results show that careful design of the cavity configuration can markedly enhance the performance of the TPV system.

The design and numerical analysis of tandem thermophotovoltaic cells

International Nuclear Information System (INIS)

Yang Hao-Yu; Liu Ren-Jun; Wang Lian-Kai; Lü You; Li Tian-Tian; Li Guo-Xing; Zhang Yuan-Tao; Zhang Bao-Lin

2013-01-01

In this paper, numerical analysis of GaSb =(E g = 0.72 eV)/Ga 0.84 In 0.16 As 0.14 Sb 0.86 (E g = 0.53 eV) tandem thermophotovoltaic (TPV) cells is carried out by using Silvaco/Atlas software. In the tandem cells, a GaSb p-n homojunction is used for the top cell and a GaInAsSb p-n homojunction for the bottom cell. A heavily doped GaSb tunnel junction connects the two sub-cells together. The simulations are carried out at a radiator temperature of 2000 K and a cell temperature of 300 K. The radiation photons are injected from the top of the tandem cells. Key properties of the single- and dual-junction TPV cells, including I–V characteristic, maximum output power (P max ), open-circuit voltage (V oc ), short-circuit current (I sc ), etc. are presented. The effects of the sub-cell thickness and carrier concentration on the key properties of tandem cells are investigated. A comparison of the dual-TPV cells with GaSb and GaInAsSb single junction cells shows that the P max of tandem cells is almost twice as great as that of the single-junction cells. (interdisciplinary physics and related areas of science and technology)

Experimental and theoretical analysis of cell module output performance for a thermophotovoltaic system

International Nuclear Information System (INIS)

Xu, Xiaojie; Ye, Hong; Xu, Yexin; Shen, Mingrong; Zhang, Xiaojing; Wu, Xi

2014-01-01

Highlights: • An accurate theoretical model for thermophotovoltaic system is constructed. • Parallel connected module is superior if radiator temperature is uneven. • Series connected module is superior if cell temperature is uneven. • Short circuit current of series module rises when the shunt resistance decreases. • Fill factor is not always accurate to evaluate the module performance. - Abstract: An experimental thermophotovoltaic (TPV) system with a cylindrical-geometry radiator was established to test the output performances of modules under different conditions. The results demonstrate that the output performance of a cell module decreases when the combustion power increases because of the uneven temperature of the radiator or cells. On this basis, a theoretical model for a TPV system was constructed to compare the performance under different conditions of the series-connected (SC) module and the parallel-connected (PC) module, and was verified by the experimental results. The influences of the temperature gradient of the radiator or the cell module, and the series and shunt resistance of the TPV cell on the module performance were analyzed in detail. The results demonstrate that the PC module can effectively reduce the mismatch loss of output power caused by the uneven radiator temperature. The PC module, for instance, has a maximum output power of 2.54 times higher than that of the SC module when the radiator temperature difference is 500 K. However, the output performance of the module connected in series is superior to the PC module while the cell temperature is non-uniform. The output power of the SC module is 9.93% higher than that of the PC module at the cell temperature difference of 125 K. The short circuit current of the SC module is sensitive to the series and shunt resistance if the radiator temperature distribution is non-uniform. As the shunt resistance falls from ∞ to 0.5 Ω, the current varies from 1.757 A to 4.488 A when the

Integration between a thermophotovoltaic generator and an Organic Rankine Cycle

International Nuclear Information System (INIS)

De Pascale, Andrea; Ferrari, Claudio; Melino, Francesco; Morini, Mirko; Pinelli, Michele

2012-01-01

Highlights: ► A new energy system comprising a Thermo-Photo-Voltaic and Organic Rankine Cycle. ► An analytical model to calculate the performance of the system is introduced. ► The system shows promising results in terms of CHP performance. -- Abstract: The constant increase in energy need and the growing attention to the related environmental impact have given a boost to the development of new strategies in order to reduce the primary energy consumption and to improve its utilization. One of the possible strategies for achieving this aim is Combined Heat and Power (CHP) specially if coupled with the concept of on-site generation (also known as distributed generation). These approaches allow the reduction of fuel consumption and pollutant emissions and the increase of security in energy supply. This paper introduces the Thermophotovoltaic Organic Rankine Cycle Integrated System (TORCIS), an energy system integrating a ThermoPhotoVoltaic generator (TPV) and an Organic Rankine Cycle (ORC). This study represents the start-up of a research program which involves three research teams from IMEM – National Research Council, ENDIF – University of Ferrara and DIEM – University of Bologna. The aim of this research is the complete definition and the pre-prototyping characterization of this system covering all the unresolved issues in this field. More specifically, TPV is a system to convert the radiation emitted from an artificial heat source (i.e. the combustion of fuel) into electrical energy by the use of photovoltaic cells. In this system, the produced electrical power is strictly connected to the thermal one as their ratio is almost constant and cannot be changed without severe loss in performance. The coupling between TPV and ORC allows this limitation to be overcome by the realization of a CHP system which can be regulated with a large degree of freedom changing the ratio between the produced electrical and thermal power. In this study a thermodynamic

Development and characterization of a rare earth emitter for a thermophotovoltaic power generator

Energy Technology Data Exchange (ETDEWEB)

Durisch, W; Panitz, J C [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Energy conversion based on thermophotovoltaic (TPV) methods has recently attracted renewed interest. Efforts at PSI are directed towards the development of a modular TPV system based on existing technology to demonstrate the feasibility of this method. Here, we report first results obtained with a prototype TPV generator based upon a modified rare earth emitter, a heat reflecting filter and commercial silicon solar cells. The preparation of the modified emitter is described, and first results of spectroscopic and electrical characterization of the TPV system are presented. The introduction of the modified emitter leads to an efficiency gain of 30-40%. (author) 3 figs., 4 refs.

Development of a portable thermophotovoltaic power generator

Science.gov (United States)

Becker, Frederick E.; Doyle, Edward F.; Shukla, Kailash

1997-03-01

A 150 Watt thermophotovoltaic (TPV) power generator is being developed. The technical approach taken in the design focused on optimizing the integrated performance of the primary subsystems in order to yield high energy conversion efficiency and cost effectiveness. An important aspect of the approach is the use of a selective emitter radiating to a bandgap matched photovoltaic array to minimize thermal and optical recuperation requirements, as well as the non-recoverable heat losses. For the initial prototype system, fibrous ytterbia emitters radiating in a band centered at 980 nm are matched with high efficiency silicon photoconverters. The integrated system includes a dielectric stack filter for optical energy recovery and a ceramic recuperator for thermal energy recovery. The system has been operated with air preheat temperatures up to 1350K. The design of the system and development status are presented.

Quaternary InGaAsSb Thermophotovoltaic Diode Technology

International Nuclear Information System (INIS)

M Dashiell; J Beausang; H Ehsani; G Nichols; D DePoy; L Danielson; P Talamo; K Rahner; E Brown; S Burger; P Fourspring; W Topper; P Baldasaro; C Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryl

2005-01-01

Thermophotovoltaic (TPV) diodes fabricated from InGaAsSb alloys lattice-matched to GaSb substrates are grown by Metal Organic Vapor Phase Epitaxy (MOVPE). 0.53eV InGaAsSb TPV diodes utilizing front-surface spectral control filters have been tested in a vacuum cavity and a TPV thermal-to-electric conversion efficiency (η TPV ) and a power density (PD) of η TPV = 19% and PD=0.58 W/cm 2 were measured for T radiator = 950 C and T diode = 27 C. Recombination coefficients deduced from minority carrier measurements and the theory reviewed in this article predict a practical limit to the maximum achievable conversion efficiency and power density for 0.53eV InGaAsSb TPV. The limits for the above operating temperatures are projected to be η TPV = 26% and PD = 0.75 W/cm 2 . These limits are extended to η TPV = 30% and PD = 0.85W/cm 2 if the diode active region is bounded by a reflective back surface to enable photon recycling and a two-pass optical path length. The internal quantum efficiency of the InGaAsSb TPV diode is close to the theoretically predicted limits, with the exception of short wavelength absorption in GaSb contact layers. Experiments show that the open circuit voltage of the 0.53eV InGaAsSb TPV diodes is not strongly dependent on the device architectures studied in this work where both N/P and P/N double heterostructure diodes have been grown with various acceptor and donor doping levels, having GaSb and AlGaAsSb confinement, and also partial back surface reflectors. Lattice matched InGaAsSb TPV diodes were fabricated with bandgaps ranging from 0.6 to 0.5eV without significant degradation of the open circuit voltage factor, quantum efficiency, or fill factor as the composition approached the miscibility gap. The key diode performance parameter which is limiting efficiency and power density below the theoretical limits in InGaAsSb TPV devices is the open circuit voltage. The open circuit voltages of state-of-the-art 0.53eV InGaAsSb TPV diode are ∼10

Combustion powered thermophotovoltaic emitter system

Energy Technology Data Exchange (ETDEWEB)

McHenry, R.S. [Naval Academy, Annapolis, MD (United States). Naval Architecture, Ocean and Marine Engineering

1995-07-01

The US Naval Academy (USNA) has recently completed an engineering design project for a high temperature thermophotovoltaic (TPV) photon emitter. The final apparatus was to be portable, completely self contained, and was to incorporate cycle efficiency optimization such as exhaust stream recuperation. Through computer modeling and prototype experimentation, a methane fueled emitter system was designed from structural ceramic materials to fulfill the high temperature requirements necessary for high system efficiency. This paper outlines the engineering design process, discusses obstacles and solutions encountered, and presents the final design.

Recombination Processes on Low Bandgap Antimonides for Thermophotovoltaic Applications

Energy Technology Data Exchange (ETDEWEB)

Saroop, Sudesh [Rensselaer Polytechnic Inst., Troy, NY (United States)

1999-09-01

Recombination processes in antimonide-based (TPV) devices have been investigated using a technique, in which a Nd-YAG pulsed laser is materials for thermophotovoltaic radio-frequency (RF) photoreflectance used to excite excess carriers and the short-pulse response and photoconductivity decay are monitored with an inductively-coupled non-contacting RF probe. The system has been used to characterize surface and bulk recombination mechanisms in Sb-based materials.

Operating experience of a portable thermophotovoltaic power supply

Science.gov (United States)

Becker, Frederick E.; Doyle, Edward F.; Shukla, Kailash

1999-03-01

Two configurations of man-portable thermophotovoltaic (TPV) power supplies based on Thermo Power's supported continuous fiber emitter have been designed, built, and are being tested. The systems use narrow-band, fibrous, ytterbia emitters radiating to bandgap matched silicon photovoltaic arrays with dielectric stack filters for optical energy recovery and recuperators for thermal energy recovery. The systems have been designed for operation with propane and with combustion air preheat temperatures of up to 1250 K. To operate at air preheat temperatures above the auto-ignition temperature of the fuel, a unique fuel delivery system was devised which results in the micromixing and rapid combustion of the fuel and air right in the emitter fibers. This allows the ytterbia emitter fibers to run much hotter (˜2000 K) than any of the surrounding structure.

500 Watt Diesel Fueled TPV Portable Power Supply

Science.gov (United States)

Horne, W. E.; Morgan, M. D.; Sundaram, V. S.; Butcher, T.

2003-01-01

A test-bed 500 watt diesel fueled thermophotovoltaic (TPV) portable power supply is described. The goal of the design is a compact, rugged field portable unit weighing less than 15 pounds without fuel. The conversion efficiency goal is set at 15% fuel energy to electric energy delivered to an external load at 24 volts. A burner/recuperator system has been developed to meet the objectives of high combustion air preheat temperatures with a compact heat exchanger, low excess air operation, and high convective heat transfer rates to the silicon carbide emitter surface. The burner incorporates a air blast atomizer with 100% of the combustion air passing through the nozzle. Designed firing rate of 2900 watts at 0.07 gallons of oil per hour. This incorporates a single air supply dc motor/fan set and avoids the need for a system air compressor. The recuperator consists of three annular, concentric laminar flow passages. Heat from the combustion of the diesel fuel is both radiantly and convectively coupled to the inside wall of a cylindrical silicon carbide emitter. The outer wall of the emitter then radiates blackbody energy at the design temperature of 1400°C. The cylindrical emitter is enclosed in a quartz envelope that separates it from the photovoltaic (PV) cells. Spectral control is accomplished by a resonant mesh IR band-pass filter placed between the emitter and the PV array. The narrow band of energy transmitted by the filter is intercepted and converted to electricity by an array of GaSb PV cells. The array consists of 216 1-cm × 1-cm GaSb cells arranged into series and parallel arrays. An array of heat pipes couple the PV cell arrays to a heat exchanger which is cooled by forced air convection. A brief status of the key TPV technologies is presented followed by data characterizing the performance of the 500 watt TPV system.

Front Surface Tandem Filters using Sapphire (Al2O3) Substrates for Spectral Control in thermophotovoltaic Energy Conversion Systems

International Nuclear Information System (INIS)

T Rahmlow, Jr.; J Lazo-Wasem; E Gratrix; P Fourspring; D DePoy

2005-01-01

Front surface filters provide an effective means of improving thermophotovoltaic (TPV) system efficiency through spectral control of incident radiant energy. A front surface filter reflects the below band gap photons that can not be converted by the TPV cell back towards the high temperature radiator and allows convertible above band gap photons to pass through the filter into the TPV cell for conversion to electricity. The best spectral control efficiency to date has been demonstrated by front surface, tandem filters that combine an interference filter and an InPAs layer (plasma filter) in series. The InPAs material is a highly doped, epitaxially grown layer on an InP substrate. These tandem filter designs have been fabricated with energy and angle weighted spectral efficiencies of 76% for TPV cells with a 2.08(micro)m (0.6eV) band gap [1]. An alternative to the InPAs layer on an InP substrate is an Al 2 O 3 (sapphire) substrate. The use of Al 2 O 3 may increase transmission of above band gap photons, increase the mechanical strength of the tandem filter, and lower the cost of the tandem filter, all at the expense of lower spectral efficiency. This study presents design and fabrication results for front surface tandem filters that use an Al 2 O 3 substrate for 2.08(micro)m band gap TPV cells

Solid State Microchp Based On Thermophotovoltaic And Thermoelectric Conversion

OpenAIRE

Worek, William M.; Brown, Christopher; Trojanowski, Rebecca; Butcher, Thomas; Horne, Edward

2012-01-01

MicroCHP involves the coproduction of both heat and electric power in (typically) residential heating systems. A range of different energy conversion technologies are currently receiving attention for this application including Stirling engines, internal combustion engines, fuel cells, and Rankine cycles with steam or organic compounds as working fluids. In this work the use of ThermoPhotoVoltaic (TPV) and ThermoElectric (TE) conversion devices either alone or in combination for power product...

Micro combustion in sub-millimeter channels for novel modular thermophotovoltaic power generators

International Nuclear Information System (INIS)

Pan, J F; Tang, A K; Duan, L; Li, X C; Yang, W M; Chou, S K; Xue, H

2010-01-01

The performance of micro combustion-driven power systems is strongly influenced by the combustor structure. A novel modular thermophotovoltaic (TPV) power generator is presented, which is based on the sub-millimeter parallel plate combustor. It has the potential to achieve a high power density because of the high radiation energy per unit volume due to the high surface-to-volume ratio of the micro-combustor. The work experimentally investigated the ignition limitation for two micro-combustors. It also studied the effects of three major parameters on a sub-millimeter combustor, namely hydrogen to oxygen mixing ratio, hydrogen volumetric flow rate and nozzle geometry. The results show that the combustion efficiency decreases with the increase of the hydrogen flow rate, which is caused by reduced residence time. The average wall temperature with the rectangular nozzle is 25 K higher than that with the circle nozzle. The output electrical power and power density of the modular TPV power generator are projected to be 0.175 W and 0.0722 W cm −3 respectively. We experimentally achieve 0.166 W of electrical power, which is in good agreement with the model prediction

The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corporation

Energy Technology Data Exchange (ETDEWEB)

EJ Brown; PF Baldasaro; SR Burger; LR Danielson; DM DePoy; JM Dolatowski; PM Fourspring; GJ Nichols; WF Topper; TD Rahmlow

2004-07-29

In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photocells which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. Our development efforts have concentrated on flat-plate geometries with greybody radiators, front surface tandem filters and a multi-chip module (MCM) approach that allows selective fabrication processes to match cell performance. Recently, we discontinued development of GaInAsSb quaternary cell semiconductor material in favor of ternary GaInAs material. In our last publication (Ref. 1), the authors reported conversion efficiencies of about 20% (radiator 950 C, cells 22 C) for small modules (1-4 cm{sup 2}) tested in a prototypic cavity test environment. Recently, we have achieved measured conversion efficiencies of about 12.5% in larger ({approx}100 cm{sup 2}) test arrays. The efficiency reduction in the larger arrays was probably due to quality and variation of the cells as well as non-uniform illumination from the hot radiator to the cold plate. Modules in these tests used GaInAsSb cells with 0.52 eV bandgap and front surface filters for spectral control. This paper provides details of the individual system components and the rationale for our technical decisions. It also describes the measurement techniques used to record these efficiencies.

Maximal near-field radiative heat transfer between two plates

OpenAIRE

Nefzaoui, Elyes; Ezzahri, Younès; Drevillon, Jérémie; Joulain, Karl

2013-01-01

International audience; Near-field radiative transfer is a promising way to significantly and simultaneously enhance both thermo-photovoltaic (TPV) devices power densities and efficiencies. A parametric study of Drude and Lorentz models performances in maximizing near-field radiative heat transfer between two semi-infinite planes separated by nanometric distances at room temperature is presented in this paper. Optimal parameters of these models that provide optical properties maximizing the r...

Minority-carrier transport in InGaAsSb thermophotovoltaic diodes

International Nuclear Information System (INIS)

Charache, G.; Martinelli, R.U.; Garbuzov, D.Z.; Lee, H.; Morris, N.; Odubanjo, T.; Connolly, J.C.

1997-05-01

Uncoated InGaAsSb/GaSb thermophotovoltaic (TPV) diodes with 0.56 eV (2.2 microm) bandgaps exhibit external quantum efficiencies of 59% at 2 microm. The devices have electron diffusion lengths as long as 29 microm in 8-microm-wide p-InGaAsSb layers and hole diffusion lengths of 3 microm in 6-microm-wide n-InGaAsSb layers. The electron and hole diffusion lengths appear to increase with increasing p- and n-layer widths. At 632.8 nm the internal quantum efficiencies of diodes with 1- to 8-microm-wide p-layers are above 89% and are independent of the p-layer width, indicating long electron diffusion lengths. InGaAsSb has, therefore, excellent minority carrier transport properties that are well suited to efficient TPV diode operation. The structures were grown by molecular-beam epitaxy

Ultra high temperature latent heat energy storage and thermophotovoltaic energy conversion

OpenAIRE

Datas Medina, Alejandro; Ramos Cabal, Alba; Martí Vega, Antonio; Cañizo Nadal, Carlos del; Luque López, Antonio

2016-01-01

A conceptual energy storage system design that utilizes ultra high temperature phase change materials is presented. In this system, the energy is stored in the form of latent heat and converted to electricity upon demand by TPV (thermophotovoltaic) cells. Silicon is considered in this study as PCM (phase change material) due to its extremely high latent heat (1800 J/g or 500 Wh/kg), melting point (1410 C), thermal conductivity (~25 W/mK), low cost (less than $2/kg or $4/kWh) and a...

An integrated microcombustor and photonic crystal emitter for thermophotovoltaics

Science.gov (United States)

Chan, Walker R.; Stelmakh, Veronika; Allmon, William R.; Waits, Christopher M.; Soljacic, Marin; Joannopoulos, John D.; Celanovic, Ivan

2016-11-01

Thermophotovoltaic (TPV) energy conversion is appealing for portable millimeter- scale generators because of its simplicity, but it relies on a high temperatures. The performance and reliability of the high-temperature components, a microcombustor and a photonic crystal emitter, has proven challenging because they are subjected to 1000-1200°C and stresses arising from thermal expansion mismatches. In this paper, we adopt the industrial process of diffusion brazing to fabricate an integrated microcombustor and photonic crystal by bonding stacked metal layers. Diffusion brazing is simpler and faster than previous approaches of silicon MEMS and welded metal, and the end result is more robust.

Photocell modelling for thermophotovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Mayor, J -C; Durisch, W; Grob, B; Panitz, J -C [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Goal of the modelling described here is the extrapolation of the performance characteristics of solar photocells to TPV working conditions. The model accounts for higher flux of radiation and for the higher temperatures reached in TPV converters. (author) 4 figs., 1 tab., 2 refs.

An integrated microcombustor and photonic crystal emitter for thermophotovoltaics

International Nuclear Information System (INIS)

Chan, Walker R.; Stelmakh, Veronika; Joannopoulos, John D.; Celanovic, Ivan; Allmon, William R.; Waits, Christopher M.; Soljacic, Marin

2016-01-01

Thermophotovoltaic (TPV) energy conversion is appealing for portable millimeter- scale generators because of its simplicity, but it relies on a high temperatures. The performance and reliability of the high-temperature components, a microcombustor and a photonic crystal emitter, has proven challenging because they are subjected to 1000-1200°C and stresses arising from thermal expansion mismatches. In this paper, we adopt the industrial process of diffusion brazing to fabricate an integrated microcombustor and photonic crystal by bonding stacked metal layers. Diffusion brazing is simpler and faster than previous approaches of silicon MEMS and welded metal, and the end result is more robust. (paper)

Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

Science.gov (United States)

Seyf, Hamid Reza; Henry, Asegun

2017-01-01

We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

Power and hydrogen production from ammonia in a micro-thermophotovoltaic device integrated with a micro-reformer

International Nuclear Information System (INIS)

Um, Dong Hyun; Kim, Tae Young; Kwon, Oh Chae

2014-01-01

Power and hydrogen (H 2 ) production by burning and reforming ammonia (NH 3 ) in a micro-TPV (microscale-thermophotovoltaic) device integrated with a micro-reformer is studied experimentally. A heat-recirculating micro-emitter with the cyclone and helical adapters that enhance the residence time of fed fuel-air mixtures and uniform burning burns H 2 -added NH 3 -air mixtures. A micro-reformer that converts NH 3 to H 2 using ruthenium as a catalyst surrounds the micro-emitter as a heat source. The micro-reformer is surrounded by a chamber, the inner and outer walls of which have installations of gallium antimonide photovoltaic cells and cooling fins. For the micro-reformer-integrated micro-TPV device the maximum overall efficiency of 8.1% with electrical power of 4.5 W and the maximum NH 3 conversion rate of 96.0% with the H 2 production rate of 22.6 W (based on lower heating value) are obtained, indicating that the overall efficiency is remarkably enhanced compared with 2.0% when the micro-TPV device operates alone. This supports the potential of improving the overall efficiency of a micro-TPV device through integrating it with a micro-reformer. Also, the feasibility of using NH 3 as a carbon-free fuel for both burning and reforming in practical micro power and H 2 generation devices has been demonstrated. - Highlights: • Performance of micro-TPV device integrated with micro-reformer is evaluated. • Feasibility of using NH 3 –H 2 blends in integrated system has been demonstrated. • Integration with micro-reformer improves performance of micro-TPV device. • Maximum overall efficiency of 8.1% is found compared with 2.0% without integration

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology

International Nuclear Information System (INIS)

MW Dashiell; JF Beausang; G Nichols; DM Depoy; LR Danielson; H Ehsani; KD Rahner; J Azarkevich; P Talamo; E Brown; S Burger; P Fourspring; W Topper; PF Baldasaro; CA Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Marinelli; D Donetski; S Anikeev; G Belenky; S Luryi; DR Taylor; J Hazel

2004-01-01

Thermophotovoltaic (TPV) diodes fabricated from 0.52eV lattice-matched InGaAsSb alloys are grown by Metal Organic Vapor Phase Epitaxy (MOVPE) on GaSb substrates. 4cm 2 multi-chip diode modules with front-surface spectral filters were tested in a vacuum cavity and attained measured efficiency and power density of 19% and 0.58 W/cm 2 respectively at operating at temperatures of T radiator = 950 C and T diode = 27 C. Device modeling and minority carrier lifetime measurements of double heterostructure lifetime specimens indicate that diode conversion efficiency is limited predominantly by interface recombination and photon energy loss to the GaSb substrate and back ohmic contact. Recent improvements to the diode include lattice-matched p-type AlGaAsSb passivating layers with interface recombination velocities less than 100 cm/s and new processing techniques enabling thinned substrates and back surface reflectors. Modeling predictions of these improvements to the diode architecture indicate that conversion efficiencies from 27-30% and ∼0.85 W/cm 2 could be attained under the above operating temperatures

Maximal near-field radiative heat transfer between two plates

Science.gov (United States)

Nefzaoui, Elyes; Ezzahri, Younès; Drévillon, Jérémie; Joulain, Karl

2013-09-01

Near-field radiative transfer is a promising way to significantly and simultaneously enhance both thermo-photovoltaic (TPV) devices power densities and efficiencies. A parametric study of Drude and Lorentz models performances in maximizing near-field radiative heat transfer between two semi-infinite planes separated by nanometric distances at room temperature is presented in this paper. Optimal parameters of these models that provide optical properties maximizing the radiative heat flux are reported and compared to real materials usually considered in similar studies, silicon carbide and heavily doped silicon in this case. Results are obtained by exact and approximate (in the extreme near-field regime and the electrostatic limit hypothesis) calculations. The two methods are compared in terms of accuracy and CPU resources consumption. Their differences are explained according to a mesoscopic description of nearfield radiative heat transfer. Finally, the frequently assumed hypothesis which states a maximal radiative heat transfer when the two semi-infinite planes are of identical materials is numerically confirmed. Its subsequent practical constraints are then discussed. Presented results enlighten relevant paths to follow in order to choose or design materials maximizing nano-TPV devices performances.

Super-Planckian Thermophotovoltaics Without Vacuum Gaps

Science.gov (United States)

Mirmoosa, M. S.; Biehs, S.-A.; Simovski, C. R.

2017-11-01

We introduce the concept of a thermophotovoltaic system whose emitter is separated from the photovoltaic cell by an intermediate thick slab of gallium arsenide. Owing to the engineered structure of the emitter (a multilayer structure of negative- and positive-ɛ layers) together with a high refractiveindex and transparency of the intermediate slab, we achieve a super-Planckian and frequency-selective spectrum of radiative heat transfer which is desirable for the efficient performance of thermophotovoltaic systems.

Photonic Crystal Emitters for Thermophotovoltaic Energy Conversion

International Nuclear Information System (INIS)

Stelmakh, Veronika; Chan, Walker R; Joannopoulos, John D; Celanovic, Ivan; Ghebrebrhan, Michael; Soljacic, Marin

2015-01-01

This paper reports the design, fabrication, and characterization of 2D photonic crystal (PhC) thermal emitters for a millimeter-scale hydrocarbon TPV microgenerator as a possible replacement for batteries in portable microelectronics, robotics, etc. In our TPV system, combustion heats a PhC emitter to incandescence and the resulting radiation is converted by a low-bandgap TPV cell. The PhC tailors the photonic density of states to produce spectrally confined thermal emission that matches the bandgap of the TPV cell, enabling high heat-to-electricity conversion efficiency. The work builds on a previously developed fabrication process to produce a square array of cylindrical cavities in a metal substrate. We will present ongoing incremental improvements in the optical and thermo-mechanical properties, the fabrication process, and the system integration, as recently combined with fabrication using novel materials, such as sputtered coatings, to enable a monolithic system. (paper)

High efficiency thermal to electric energy conversion using selective emitters and spectrally tuned solar cells

Science.gov (United States)

Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

1992-01-01

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 1500 K. Depending on the nature of parasitic losses, overall thermal-to-electric conversion efficiencies greater than 20 percent are feasible.

Heat Transfer Modelling of Glass Media within TPV Systems

Science.gov (United States)

Bauer, Thomas; Forbes, Ian; Penlington, Roger; Pearsall, Nicola

2004-11-01

Understanding and optimisation of heat transfer, and in particular radiative heat transfer in terms of spectral, angular and spatial radiation distributions is important to achieve high system efficiencies and high electrical power densities for thermophtovoltaics (TPV). This work reviews heat transfer models and uses the Discrete Ordinates method. Firstly one-dimensional heat transfer in fused silica (quartz glass) shields was examined for the common arrangement, radiator-air-glass-air-PV cell. It has been concluded that an alternative arrangement radiator-glass-air-PV cell with increased thickness of fused silica should have advantages in terms of improved transmission of convertible radiation and enhanced suppression of non-convertible radiation.

Solar-Powered, Micron-Gap Thermophotovoltaics for MEO Applications, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed innovation is an InGaAs-based, radiation-tolerant, micron-gap thermophotovoltaic (MTPV) technology. The use of a micron wide gap between the radiation...

Radiative heat transfer enhancement using geometric and spectral control for achieving high-efficiency solar-thermophotovoltaic systems

Science.gov (United States)

Kohiyama, Asaka; Shimizu, Makoto; Yugami, Hiroo

2018-04-01

We numerically investigate radiative heat transfer enhancement using spectral and geometric control of the absorber/emitter. A high extraction of the radiative heat transfer from the emitter as well as minimization of the optical losses from the absorber leads to high extraction and solar thermophotovoltaic (STPV) system efficiency. The important points for high-efficiency STPV design are discussed for the low and high area ratio of the absorber/emitter. The obtained general guideline will support the design of various types of STPV systems.

Appropriate materials and preparation techniques for polycrystalline-thin-film thermophotovoltaic cells

Science.gov (United States)

Dhere, Neelkanth G.

1997-03-01

Polycrystalline-thin-film thermophotovoltaic (TPV) cells have excellent potential for reducing the cost of TPV generators so as to address the hitherto inaccessible and highly competitive markets such as self-powered gas-fired residential warm air furnaces and energy-efficient electric cars, etc. Recent progress in polycrystalline-thin-film solar cells have made it possible to satisfy the diffusion length and intrinsic junction rectification criteria for TPV cells operating at high fluences. Continuous ranges of direct bandgaps of the ternary and pseudoternary compounds such as Hg1-xCdxTe, Pb1-xCdxTe, Hg1-xZnxTe, and Pb1-xZnxS cover the region of interest of 0.50-0.75 eV for efficient TPV conversion. Other ternary and pseudoternary compounds which show direct bandgaps in most of or all of the 0.50-0.75 eV range are Pb1-xZnxTe, Sn1-xCd2xTe2, Pb1-xCdxSe, Pb1-xZnxSe, and Pb1-xCdxS. Hg1-xCdxTe (with x~0.21) has been studied extensively for infrared detectors. PbTe and Pb1-xSnxTe have also been studied for infrared detectors. Not much work has been carried out on Hg1-xZnxTe thin films. Hg1-xCdxTe and Pb1-xCdxTe alloys cover a wide range of cut-off wavelengths from the far infrared to the near visible. Acceptors and donors are introduced in these materials by excess non-metal (Te) and excess metal (Hg and Pb) respectively. Extrinsic acceptor impurities are Cu, Au, and As while and In and Al are donor impurities. Hg1-xCdxTe thin films have been deposited by isothermal vapor-phase epitaxy (VPE), liquid phase epitaxy (LPE), hot-wall metalorganic chemical vapor deposition (MOCVD), electrodeposition, sputtering, molecular beam epitaxy (MBE), laser-assisted evaporation, and vacuum evaporation with or without hot-wall enclosure. The challenge in the preparation of Hg1-xCdxTe is to provide excess mercury incidence rate, to optimize the deposition parameters for enhanced mercury incorporation, and to achieve the requisite stoichiometry, grain size, and doping. MBE and MOCVD

Quantum-Well Thermophotovoltaic Cells

Science.gov (United States)

Freudlich, Alex; Ignatiev, Alex

2009-01-01

Thermophotovoltaic cells containing multiple quantum wells have been invented as improved means of conversion of thermal to electrical energy. The semiconductor bandgaps of the quantum wells can be tailored to be narrower than those of prior thermophotovoltaic cells, thereby enabling the cells to convert energy from longer-wavelength photons that dominate the infrared-rich spectra of typical thermal sources with which these cells would be used. Moreover, in comparison with a conventional single-junction thermophotovoltaic cell, a cell containing multiple narrow-bandgap quantum wells according to the invention can convert energy from a wider range of wavelengths. Hence, the invention increases the achievable thermal-to-electrical energy-conversion efficiency. These thermophotovoltaic cells are expected to be especially useful for extracting electrical energy from combustion, waste-heat, and nuclear sources having temperatures in the approximate range from 1,000 to 1,500 C.

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.

High efficiency direct thermal to electric energy conversion from radioisotope decay using selective emitters and spectrally tuned solar cells

International Nuclear Information System (INIS)

Chubb, D.L.; Flood, D.J.; Lowe, R.A.

1993-08-01

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

Graphene-on-Silicon Near-Field Thermophotovoltaic Cell

NARCIS (Netherlands)

Svetovoy, V. B.; Palasantzas, G.

2014-01-01

A graphene layer on top of a dielectric can dramatically influence the ability of the material for radiative heat transfer. This property of graphene is used to improve the performance and reduce costs of near-field thermophotovoltaic cells. Instead of low-band-gap semiconductors it is proposed to

Cost estimate of electricity produced by TPV

Science.gov (United States)

Palfinger, Günther; Bitnar, Bernd; Durisch, Wilhelm; Mayor, Jean-Claude; Grützmacher, Detlev; Gobrecht, Jens

2003-05-01

A crucial parameter for the market penetration of TPV is its electricity production cost. In this work a detailed cost estimate is performed for a Si photocell based TPV system, which was developed for electrically self-powered operation of a domestic heating system. The results are compared to a rough estimate of cost of electricity for a projected GaSb based system. For the calculation of the price of electricity, a lifetime of 20 years, an interest rate of 4.25% per year and maintenance costs of 1% of the investment are presumed. To determine the production cost of TPV systems with a power of 12-20 kW, the costs of the TPV components and 100 EUR kW-1el,peak for assembly and miscellaneous were estimated. Alternatively, the system cost for the GaSb system was derived from the cost of the photocells and from the assumption that they account for 35% of the total system cost. The calculation was done for four different TPV scenarios which include a Si based prototype system with existing technology (etasys = 1.0%), leading to 3000 EUR kW-1el,peak, an optimized Si based system using conventional, available technology (etasys = 1.5%), leading to 900 EUR kW-1el,peak, a further improved system with future technology (etasys = 5%), leading to 340 EUR kW-1el,peak and a GaSb based system (etasys = 12.3% with recuperator), leading to 1900 EUR kW-1el,peak. Thus, prices of electricity from 6 to 25 EURcents kWh-1el (including gas of about 3.5 EURcents kWh-1) were calculated and compared with those of fuel cells (31 EURcents kWh-1) and gas engines (23 EURcents kWh-1).

Thermophotovoltaic Energy Conversion in Space Nuclear Reactor Power Systems

National Research Council Canada - National Science Library

Presby, Andrew L

2004-01-01

.... This has potential benefits for space nuclear reactor power systems currently in development. The primary obstacle to space operation of thermophotovoltaic devices appears to be the low heat rejection temperatures which necessitate large radiator areas...

A Monolithic Interconnected module with a tunnel Junction for Enhanced Electrical and Optical Performance

Energy Technology Data Exchange (ETDEWEB)

Murray, Christopher Sean; Wilt, David Morgan

1999-06-30

An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMs), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

Triple and Quadruple Junctions Thermophotovoltaic Devices Lattice Matched to InP

Science.gov (United States)

Bhusal, L.; Freundlich, A.

2007-01-01

Thermophotovoltaic (TPV) conversion of IR radiation emanating from a radioisotope heat source is under consideration for deep space exploration. Ideally, for radiator temperatures of interest, the TPV cell must convert efficiently photons in the 0.4-0.7 eV spectral range. Best experimental data for single junction cells are obtained for lattice-mismatched 0.55 eV InGaAs based devices. It was suggested, that a tandem InGaAs based TPV cell made by monolithically combining two or more lattice mismatched InGaAs subcells on InP would result in a sizeable efficiency improvement. However, from a practical standpoint the implementation of more than two subcells with lattice mismatch systems will require extremely thick graded layers (defect filtering systems) to accommodate the lattice mismatch between the sub-cells and could detrimentally affect the recycling of the unused IR energy to the emitter. A buffer structure, consisting of various InPAs layers, is incorporated to accommodate the lattice mismatch between the high and low bandgap subcells. There are evidences that the presence of the buffer structure may generate defects, which could extend down to the underlying InGaAs layer. The unusual large band gap lowering observed in GaAs(1-x)N(x) with low nitrogen fraction [1] has sparked a new interest in the development of dilute nitrogen containing III-V semiconductors for long-wavelength optoelectronic devices (e.g. IR lasers, detector, solar cells) [2-7]. Lattice matched Ga1-yInyNxAs1-x on InP has recently been investigated for the potential use in the mid-infrared device applications [8], and it could be a strong candidate for the applications in TPV devices. This novel quaternary alloy allows the tuning of the band gap from 1.42 eV to below 1 eV on GaAs and band gap as low as 0.6eV when strained to InP, but it has its own limitations. To achieve such a low band gap using the quaternary Ga1-yInyNxAs1-x, either it needs to be strained on InP, which creates further

Triple-axis X-ray reciprocal space mapping of In{sub y}Ga{sub 1-y}As thermophotovoltaic diodes grown on (1 0 0) InP substrates

Energy Technology Data Exchange (ETDEWEB)

Dashiell, M.W.; Ehsani, H.; Sander, P.C. [Lockheed Martin Corporation, Schenectady, NY 12301-1072 (United States); Newman, F.D. [Emcore Corporation, Albuquerque, NM 87123 (United States); Wang, C.A. [MIT Lincoln Laboratory, Lexington, MA 02420 (United States); Shellenbarger, Z.A. [Sarnoff Corporation, Princeton NJ, 08543-5300 (United States); Donetski, D.; Gu, N.; Anikeev, S. [Department of Electrical Engineering, State University of New York, Stony Brook, NY 11794-2350 (United States)

2008-09-15

Analysis of the composition, strain-relaxation, layer-tilt, and the crystalline quality of In{sub y}Ga{sub 1-y}As/InP{sub 1-x}As{sub x} thermophotovoltaic (TPV) diodes grown by metal-organic vapor phase epitaxy (MOVPE) is demonstrated using triple-axis X-ray reciprocal space mapping techniques. In{sub 0.53}Ga{sub 0.47}As (E{sub gap}=0.74 eV) n/p junction diodes are grown lattice matched (LM) to InP substrates and lattice-mismatched (LMM) In{sub 0.67}Ga{sub 0.33}As (E{sub gap}=0.6 eV) TPV diodes are grown on three-step InP{sub 1-x}As{sub x} (0TPV active layer and underlying InP{sub 1-x}As{sub x} buffers. Triple-axis X-ray rocking curves about the LMM In{sub 0.67}Ga{sub 0.33}As RELP show an order of magnitude increase of its full-width at half-maximum (FWHM) compared to that from the LM In{sub 0.53}Ga{sub 0.47}As (250 vs. 30 arcsec). Despite the significant RELP broadening, the photovoltaic figure of merits show that the electronic quality of the LMM In{sub 0.67}Ga{sub 0.33}As approaches that of the LM diode material. This indicates that misfit-related crystalline imperfections are not dominating the photovoltaic response of the optimized LMM In{sub 0.67}Ga{sub 0.33}As material compared with the intrinsic recombination processes and/or recombination through native point defects, which would be present in both LMM and LM diode material. However, additional RELP broadening in non-optimized LMM In{sub 0.67}Ga{sub 0.33}As n/p junction diodes does correspond to significant degradation of TPV diode open-circuit voltage and minority carrier lifetime demonstrating that there is correlation between X-ray FWHM and the electronic performance of the LMM TPV diodes. (author)

Solid State Energy Conversion for Deep Space Power

Data.gov (United States)

National Aeronautics and Space Administration — Thermophotovoltaic (TPV) devices employed in static radioisotope generators show great promise for highly efficient, reliable, and resilient power generation for...

Effect of addition of organo clay on mechanical properties and dynamic-mechanical based TPV; Preparacao de termoplasticos vulcanizados dinamicamente (TPV) de NBR/PP com nanocargas de argila

Energy Technology Data Exchange (ETDEWEB)

Honorato, Luciana R.; Silva, Adriana A.; Soares, Bluma G. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano, Rio de Janeiro, RJ (Brazil); Soares, Ketly P. [Centro Universitario do Leste de Minas Gerais (UNILESTEMG) - Coronel Fabriciano, MG (Brazil)

2011-07-01

The effect of organophilic clay on the mechanical and dynamical-mechanical properties of thermoplastic elastomers based on polypropylene (PP) and nitrile rubber (NBR) was investigated. The addition of clay was performed from a master batch prepared by a solution intercalation of NBR inside the clay galleries. Since the PP/NBR blend is highly incompatible, PP functionalized with maleic anhydride (PP-g-MA) and carboxylated NBR (XNBR) were employed as compatibilizing system together with triethylene-tetramine (TETA) used as coupling agent. The addition of Clay inside the elastomeric phase of the TPV resulted in a significant decrease of the elongation at break without changes on the tensile strength. The presence of clay also promoted a slight increase of the storage modulus and the glass transition temperature. The small angle X ray scattering confirmed the high dispersion of clay inside the TPV. Analysis of light scattering small angle (SAXS) confirmed the high dispersion of clay in the matrix of the TPV. (author)

Solar thermophotovoltaic system using nanostructures.

Science.gov (United States)

Ungaro, Craig; Gray, Stephen K; Gupta, Mool C

2015-09-21

This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is both easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids.

High-Performance, 0.6-eV, GA0.32In0.68As/In0.32P0.68 Thermophotovoltaic Converters and Monolithically Interconnected Modules

International Nuclear Information System (INIS)

Duda, A.; Murray, C.S.

1998-01-01

Recent progress in the development of high-performance, 0.6-eV Ga0.32In0.68As/InAs0.32P0.68 thermophotovoltaic (TPV) converters and monolithically interconnected modules (MIMs) is described. The converter structure design is based on using a lattice-matched InAs0.32P0.68/Ga0.32In0.68As/InAs0.32P0.68 double-heterostructure (DH) device, which is grown lattice-mismatched on an InP substrate, with an intervening compositionally step-graded region of InAsyP1-y. The Ga0.32In0.68As alloy has a room-temperature band gap of 0.6 eV and contains a p/n junction. The InAs0.32P0.68 layers have a room-temperature band gap of 0.96 eV and serve as passivation/confinement layers for the Ga0.32In0.68As p/n junction. InAsyP1-y step grades have yielded DH converters with superior electronic quality and performance characteristics. Details of the microstructure of the converters are presented. Converters prepared for this work were grown by atmospheric-pressure metalorganic vapor-phase epitaxy (APMOVPE) and were processed using a combination of photolithography, wet-chemical etching, and conventional metal and insulator deposition techniques. Excellent performance characteristics have been demonstrated for the 0.6-eV TPV converters. Additionally, the implementation of MIM technology in these converters has been highly successful

Thermal Fluid Analysis of the Heat Sink and Chip Carrier Assembly for a US Army Research Laboratory Liquid-Fueled Thermophotovoltaic Power Source Demonstrator

Science.gov (United States)

2016-09-01

temperatures above 500 °C.1 Figure 1 describes the primary components of a TPV system : a heat source, an emitter, and a photovoltaic converter. The heat...carrier surface not covered by the photovoltaic cell. 4. Mesh The mesh was set to level 3 with the minimum gap size manually set to 0.01 inch. A...heat sink to control the temperature of the photovoltaic cell while exposed to radiation from the emitter. 15. SUBJECT TERMS TPV

Design and fabrication of spectrally selective emitter for thermophotovoltaic system by using nano-imprint lithography

Science.gov (United States)

Kim, Jong-Moo; Park, Keum-Hwan; Kim, Da-Som; Hwang, Bo-yeon; Kim, Sun-Kyung; Chae, Hee-Man; Ju, Byeong-Kwon; Kim, Young-Seok

2018-01-01

Thermophotovoltaic (TPV) systems have attracted attention as promising power generation systems that can directly convert the radiant energy produced by the combustion of fuel into electrical energy. However, there is a fundamental limit of their conversion efficiency due to the broadband distribution of the radiant spectrum. To overcome this problem, several spectrally selective thermal emitter technologies have been investigated, including the fabrication of photonic crystal (PhC) structures. In this paper, we present some design rules based on finite-a difference time-domain (FDTD) simulation results for tungsten (W) PhC emitter. The W 2D PhC was fabricated by a simple nano-imprint lithography (NIL) process, and inductive coupled plasma reactive ion etching (ICP-RIE) with an isotropic etching process, the benefits and parameters of which are presented. The fabricated W PhC emitter showed spectrally selective emission near the infrared wavelength range, and the optical properties varied depending on the size of the nano-patterns. The measured results of the fabricated prototype structure correspond well to the simulated values. Finally, compared with the performance of a flat W emitter, the total thermal emitter efficiency was almost 3.25 times better with the 2D W PhC structure.

InGaAs/InP Monolithic Interconnected Modules (MIM) for Thermophotovoltaic Applications

Science.gov (United States)

Wilt, David M.; Fatemi, Navid S.; Jenkins, Phillip P.; Weizer, Victor G.; Hoffman, Richard W., Jr.; Scheiman, David A.; Murray, Christopher S.; Riley, David R.

2004-01-01

There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between systems efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) devices series -connected on a single semi-insulating indium phosphide (InP) substrate. The MIMs are exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 sq cm device consisting of eight series interconnected cells. MIM devices, produced from 0,74 eV InGAAs, have demonstrated V(sub infinity) = 3.23 volts, J(sub sc) = 70 mA/sq cm and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurement (less than 2 microns) of these devices indicate a reflectivity of less than 82%. MIM devices produced from 0.55 eV InGaAs have also been den=monstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM1) have been demonstrated.

Effect of addition of organo clay on mechanical properties and dynamic-mechanical based TPV

International Nuclear Information System (INIS)

Honorato, Luciana R.; Silva, Adriana A.; Soares, Bluma G.; Soares, Ketly P.

2011-01-01

The effect of organophilic clay on the mechanical and dynamical-mechanical properties of thermoplastic elastomers based on polypropylene (PP) and nitrile rubber (NBR) was investigated. The addition of clay was performed from a master batch prepared by a solution intercalation of NBR inside the clay galleries. Since the PP/NBR blend is highly incompatible, PP functionalized with maleic anhydride (PP-g-MA) and carboxylated NBR (XNBR) were employed as compatibilizing system together with triethylene-tetramine (TETA) used as coupling agent. The addition of Clay inside the elastomeric phase of the TPV resulted in a significant decrease of the elongation at break without changes on the tensile strength. The presence of clay also promoted a slight increase of the storage modulus and the glass transition temperature. The small angle X ray scattering confirmed the high dispersion of clay inside the TPV. Analysis of light scattering small angle (SAXS) confirmed the high dispersion of clay in the matrix of the TPV. (author)

A nanophotonic solar thermophotovoltaic device.

Science.gov (United States)

Lenert, Andrej; Bierman, David M; Nam, Youngsuk; Chan, Walker R; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N

2014-02-01

The most common approaches to generating power from sunlight are either photovoltaic, in which sunlight directly excites electron-hole pairs in a semiconductor, or solar-thermal, in which sunlight drives a mechanical heat engine. Photovoltaic power generation is intermittent and typically only exploits a portion of the solar spectrum efficiently, whereas the intrinsic irreversibilities of small heat engines make the solar-thermal approach best suited for utility-scale power plants. There is, therefore, an increasing need for hybrid technologies for solar power generation. By converting sunlight into thermal emission tuned to energies directly above the photovoltaic bandgap using a hot absorber-emitter, solar thermophotovoltaics promise to leverage the benefits of both approaches: high efficiency, by harnessing the entire solar spectrum; scalability and compactness, because of their solid-state nature; and dispatchablility, owing to the ability to store energy using thermal or chemical means. However, efficient collection of sunlight in the absorber and spectral control in the emitter are particularly challenging at high operating temperatures. This drawback has limited previous experimental demonstrations of this approach to conversion efficiencies around or below 1% (refs 9, 10, 11). Here, we report on a full solar thermophotovoltaic device, which, thanks to the nanophotonic properties of the absorber-emitter surface, reaches experimental efficiencies of 3.2%. The device integrates a multiwalled carbon nanotube absorber and a one-dimensional Si/SiO2 photonic-crystal emitter on the same substrate, with the absorber-emitter areas optimized to tune the energy balance of the device. Our device is planar and compact and could become a viable option for high-performance solar thermophotovoltaic energy conversion.

Thermophotovoltaic cells based on In0.53Ga0.47As/InP heterostructures

International Nuclear Information System (INIS)

Karlina, L. B.; Vlasov, A. S.; Kulagina, M. M.; Timoshina, N. Kh.

2006-01-01

Reflection of infrared radiation from n-InP substrates with a rear MgF 2 /Au mirror is investigated in the wavelength range 1000-2200 nm. It is found that the reflectance weakly depends on substrate thickness and free-carrier concentration in the (0.1-6) x 10 18 cm -3 range. Thermophotovoltaic cells based on the InP/In 0.53 Ga 0.47 As lattice-matched heterostructure of p-n and n-p are fabricated by liquid-phase epitaxy and Zn and P diffusion from a gas phase. The characteristics of p-n and n-p thermophotovoltaic cells with an identical configuration of the contacts of 1 cm 2 area are determined. These characteristics are the open-circuit voltage U oc = 0.465 V, the filling factor FF = 64% at the current density of 1 A/cm 2 , and the reflectance R = 76-80% for wavelengths longer than 1.86 μm

Nonlinear viscoelastic characterization of molten thermoplastic vulcanizates (TPV) through large amplitude harmonic experiments

Energy Technology Data Exchange (ETDEWEB)

Leblanc, Jean L. [University P. and M. Curie-Paris 6, Polymer Rheology and Processing, Vitry-sur-Seine (France)

2007-10-15

The so-called thermoplastic vulcanizates (TPV) are essentially blends of a crystalline thermoplastic polymer (e.g., polypropylene) and a vulcanizable rubber composition, prepared through a special process called dynamic vulcanization, which yields a fine dispersion of micron-size crosslinked rubber particles in a thermoplastic matrix. Such materials are by nature complex polymer systems, i.e., multiphase, heterogeneous, typically disordered materials for which structure is as important as composition. Correctly assessing their rheological properties is a challenging task for several reasons: first, even if the uniformity of their composition is taken for granted, TPV are indeed very complicated materials, not only heterogeneous but also with a morphology related to their composition; second, their morphology can be affected by the flow field used; third, the migration of small labile ingredients (e.g., oil, curative residue, etc.) can in the meantime significantly change the boundary flow conditions, for instance through self-lubrication due to phase separation of the oil, or wall slip, or both. The aims of the work reported were to investigate a series of commercial TPV through the so-called Fourier transform rheometry, a testing technique especially developed to accurately investigate the nonlinear viscoelastic domain. Results are tentatively interpreted in terms of material composition and structure. (orig.)

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

Science.gov (United States)

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-01-01

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Selection of emitter material for application on a radioisotope thermophotovoltaic (RTPV) power system

Energy Technology Data Exchange (ETDEWEB)

Kramer, D.P.; Frohlich, N.D.; Koehler, F.A.; Ruhkamp, J.D.; Miller, R.G.; McDougal, J.R.; Pugh, B.K.; Barklay, C.D.; Howell, E.I. [EGG Mound Applied Technologies Building 88, P.O. Box 3000 Miamisburg, Ohio45343 (United States)

1997-01-01

Radioisotope Thermophotovoltaic (RTPV) power systems are being considered for long duration space missions due to their predicted high thermal to electrical conversion efficiencies. One critical aspect of these power systems is the selection of an appropriate emitter material which will efficiently radiate the thermal energy generated by the heat source to the photovoltaics. The photovoltaics are {open_quotes}tuned{close_quotes} to convert the infrared wavelengths radiated by the emitter into electrical energy. The emphasis of this paper is on the selection and optimization of an appropriate emitter material which would meet all of the mission requirements. A Kepner Tregoe analysis was performed in order to rank the various candidate refractory materials in relationship to their physical and chemical properties. The results of the analysis and material recommendations are discussed. {copyright} {ital 1997 American Institute of Physics.}

Near-Field Thermal Radiation for Solar Thermophotovoltaics and High Temperature Thermal Logic and Memory Applications

Science.gov (United States)

Elzouka, Mahmoud

This dissertation investigates Near-Field Thermal Radiation (NFTR) applied to MEMS-based concentrated solar thermophotovoltaics (STPV) energy conversion and thermal memory and logics. NFTR is the exchange of thermal radiation energy at nano/microscale; when separation between the hot and cold objects is less than dominant radiation wavelength (˜1 mum). NFTR is particularly of interest to the above applications due to its high rate of energy transfer, exceeding the blackbody limit by orders of magnitude, and its strong dependence on separation gap size, surface nano/microstructure and material properties. Concentrated STPV system converts solar radiation to electricity using heat as an intermediary through a thermally coupled absorber/emitter, which causes STPV to have one of the highest solar-to-electricity conversion efficiency limits (85.4%). Modeling of a near-field concentrated STPV microsystem is carried out to investigate the use of STPV based solid-state energy conversion as high power density MEMS power generator. Numerical results for In 0.18Ga0.82Sb PV cell illuminated with tungsten emitter showed significant enhancement in energy transfer, resulting in output power densities as high as 60 W/cm2; 30 times higher than the equivalent far-field power density. On thermal computing, this dissertation demonstrates near-field heat transfer enabled high temperature NanoThermoMechanical memory and logics. Unlike electronics, NanoThermoMechanical memory and logic devices use heat instead of electricity to record and process data; hence they can operate in harsh environments where electronics typically fail. NanoThermoMechanical devices achieve memory and thermal rectification functions through the coupling of near-field thermal radiation and thermal expansion in microstructures, resulting in nonlinear heat transfer between two temperature terminals. Numerical modeling of a conceptual NanoThermoMechanical is carried out; results include the dynamic response under

Hybrid thermionic-photovoltaic converter

Energy Technology Data Exchange (ETDEWEB)

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

2016-04-04

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

Parametric characteristics of a solar thermophotovoltaic system at the maximum efficiency

International Nuclear Information System (INIS)

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

2016-01-01

Graphical abstract: A model of the far-field TPVC driven by solar energy, which consists of an optical concentrator, an absorber, an emitter, and a PV cell and is simply referred as to the far-field STPVS. - Highlights: • A model of the far-field solar thermophotovoltaic system (STPVS) is established. • External and internal irreversible losses are considered. • The maximum efficiency of the STPVS is calculated. • Optimal values of key parameters at the maximum efficiency are determined. • Effects of the concentrator factor on the performance of the system are discussed. - Abstract: A model of the solar thermophotovoltaic system (STPVS) consisting of an optical concentrator, a thermal absorber, an emitter, and a photovoltaic (PV) cell is proposed, where the far-field thermal emission between the emitter and the PV cell, the radiation losses from the absorber and emitter to the environment, the reflected loss from the absorber, and the finite-rate heat exchange between the PV cell and the environment are taken into account. Analytical expressions for the power output of and overall efficiency of the STPVS are derived. By solving thermal equilibrium equations, the operating temperatures of the emitter and PV cell are determined and the maximum efficiency of the system is calculated numerically for given values of the output voltage of the PV cell and the ratio of the front surface area of the absorber to that of the emitter. For different bandgaps, the maximum efficiencies of the system are calculated and the corresponding optimum values of several operating parameters are obtained. The effects of the concentrator factor on the optimum performance of the system are also discussed.

Analysis of solar thermophotovoltaic test data from experiments performed at McDonnell Douglas

Energy Technology Data Exchange (ETDEWEB)

Stone, K.W.; Kusek, S.M.; Drubka, R.E. [McDonnell Douglas, 5301 Bolsa Avenue, Huntington Beach, California 92647 (United States); Fay, T.D. [21911 Bacalar, Mission Viejo, California 92692 (United States)

1995-01-05

Solar thermophotovoltaic power systems offer potentially high system efficiency for solar energy to electrical energy conversion and attractive system advantages. McDonnell Douglas Corporation (MDC) has been investigating this technology for both space and terrestrial applications for several years. A testbed prototype was designed, built, and tested on a 90 kW{sub t} dish concentrator at the MDA solar test facility. Twelve experiments were conducted with absorber temperatures in excess of 1300 {degree}C being achieved using only a fraction of the reflected power from the 90 kW{sub t} dish concentrator. This paper discusses the solar thermophotovoltaic testbed prototype unit, test data, and presents an analysis of the unit`s performance. A combination of analytical analysis and test data is used to obtain an understanding of the system and subsystem performance. The preliminary results of these tests and analysis indicate a solar thermophotovoltaic power system can achieve high system performance. Furthermore, system demonstrations are possible utilizing a combination of current off-the-shelf hardware components and components currently being tested in laboratories. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

A three-dimensional computational model of H2–air premixed combustion in non-circular micro-channels for a thermo-photovoltaic (TPV) application

International Nuclear Information System (INIS)

Akhtar, Saad; Kurnia, Jundika C.; Shamim, Tariq

2015-01-01

Highlights: • Flow and flame behavior in a micro-combustor are studied. • Predictive capabilities of turbulence and chemistry sub-models are evaluated. • Thermal & hydraulic performance is tested for different combustor geometries. • Excellent outer wall prediction by RSM turbulence and EDC chemistry sub-model. • Enhanced heat transfer for triangular and trapezoid combustor geometries. - Abstract: Wall temperature uniformity and enhancement in a micro combustor for thermo photovoltaic (TPV) applications have attracted considerable attention from researchers in recent years because of their direct impact on efficiency and feasibility of desired energy conversion. In this regard, numerous experimental and numerical studies in micro-combustion application have been conducted and reported. However, most previous studies have been focused on geometrical configurations limited to planar and circular channels. It is therefore of interest to investigate the impact of different channel geometries on wall temperature distribution and energy conversion efficiency. This study addresses flow and flame behavior in a micro-combustor. By utilizing the well-established computational fluid dynamics (CFD) approach, the effect of geometrical parameters on the flow behavior and wall temperature is examined and evaluated. In order to improve the productive capability of the computational model, several steady state Reynolds Average Numerical Simulation (RANS) turbulence models alongside with different reaction rate formulations are evaluated. The results indicate that Reynolds Stress Model (RSM) with Eddy Dissipation Concept (EDC) provide the best quantitative prediction. The developed model is employed to investigate the effect of inlet velocity on flame structure and outer wall temperature. Furthermore, the effect of reactor cross sections, including circular, square, rectangular, triangular and trapezoidal, on the wall temperature is also evaluated. The results show that

Metamaterial-based integrated plasmonic absorber/emitter for solar thermo-photovoltaic systems

International Nuclear Information System (INIS)

Wu, Chihhui; Neuner III, Burton; Shvets, Gennady; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve

2012-01-01

We present the concept of a solar thermo-photovoltaic (STPV) collection system based on a large-area, nanoimprint-patterned film of plasmonic structures acting as an integrated solar absorber/narrow-band thermal emitter (SANTE). The SANTE film concept is based on integrating broad-band solar radiation absorption with selective narrow-band thermal IR radiation which can be efficiently coupled to a photovoltaic (PV) cell for power generation. By employing a low reflectivity refractory metal (e.g., tungsten) as a plasmonic material, we demonstrate that the absorption spectrum of the SANTE film can be designed to be broad-band in the visible range and narrow-band in the infrared range. A detailed balance calculation demonstrates that the total STPV system efficiency exceeds the Shockley–Queisser limit for emitter temperatures above T e = 1200 K, and achieves an efficiency as high as 41% for T e = 2300 K. Emitter temperatures in this range are shown to be achievable under modest sun concentrations (less than 1000 suns) due to the thermal insulation provided by the SANTE film. An experimental demonstration of the wide-angle, frequency-selective absorptivity is presented

Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system

Science.gov (United States)

Charache, Greg W.; Baldasaro, Paul F.; Nichols, Greg J.

1998-01-01

A thermophotovoltaic energy conversion device and a method for making the device. The device includes a substrate formed from a bulk single crystal material having a bandgap (E.sub.g) of 0.4 eVternary or quaternary III-V semiconductor active layers.

Modeling of InGaSb thermophotovoltaic cells and materials

Energy Technology Data Exchange (ETDEWEB)

Zierak, M.; Borrego, J.M.; Bhat, I.; Gutmann, R.J. [Rensselaer Polytechnic Inst., Troy, NY (United States); Charache, G. [Lockheed Martin, Inc., Schenectady, NY (United States)

1997-05-01

A closed form computer program has been developed for the simulation and optimization of In{sub x}Ga{sub 1{minus}x}Sb thermophotovoltaic cells operating at room temperature. The program includes material parameter models of the energy bandgap, optical absorption constant, electron and hole mobility, intrinsic carrier concentration and index of refraction for any composition of GaInSb alloys.

Entropy flow and generation in radiative transfer between surfaces

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.M.; Basu, S. [Georgia Institute of Technolgy, Atlanta, GA (United States). George W. Woodruff School of Mechanical Engineering

2007-02-15

Entropy of radiation has been used to derive the laws of blackbody radiation and determine the maximum efficiency of solar energy conversion. Along with the advancement in thermophotovoltaic technologies and nanoscale heat radiation, there is an urgent need to determine the entropy flow and generation in radiative transfer between nonideal surfaces when multiple reflections are significant. This paper investigates entropy flow and generation when incoherent multiple reflections are included, without considering the effects of interference and photon tunneling. The concept of partial equilibrium is applied to interpret the monochromatic radiation temperature of thermal radiation, T{sub l}(l,{omega}), which is dependent on both wavelength l and direction {omega}. The entropy flux and generation can thus be evaluated for nonideal surfaces. It is shown that several approximate expressions found in the literature can result in significant errors in entropy analysis even for diffuse-gray surfaces. The present study advances the thermodynamics of nonequilibrium thermal radiation and will have a significant impact on the future development of thermophotovoltaic and other radiative energy conversion devices. (author)

Performance characteristics and parametric choices of a solar thermophotovoltaic cell at the maximum efficiency

International Nuclear Information System (INIS)

Dong, Qingchun; Liao, Tianjun; Yang, Zhimin; Chen, Xiaohang; Chen, Jincan

2017-01-01

Graphical abstract: The overall model of the solar thermophotovoltaic cell (STPVC) composed of an optical lens, an absorber, an emitter, and a photovoltaic (PV) cell with an integrated back-side reflector is updated to include various irreversible losses. - Highlights: • A new model of the irreversible solar thermophotovoltaic system is proposed. • The material and structure parameters of the system are considered. • The performance characteristics at the maximum efficiency are revealed. • The optimal values of key parameters are determined. • The system can obtain a large efficiency under a relative low concentration ratio. - Abstract: The overall model of the solar thermophotovoltaic cell (STPVC) composed of an optical lens, an absorber, an emitter, and a photovoltaic (PV) cell with an integrated back-side reflector is updated to include various irreversible losses. The power output and efficiency of the cell are analytically derived. The performance characteristics of the STPVC at the maximum efficiency are revealed. The optimum values of several important parameters, such as the voltage output of the PV cell, the area ratio of the absorber to the emitter, and the band-gap of the semiconductor material, are determined. It is found that under the condition of a relative low concentration ratio, the optimally designed STPVC can obtain a relative large efficiency.

Fiscal 1999 research and development of technologies for practical application of photovoltaic power generation systems. Development of ultrahigh-efficiency crystalline compound solar cell manufacturing technology (Survey of peripheral element technologies - Survey of novel voltaic cell structure solar cell development); 1999 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu seika hokokusho. Chokokoritsu kessho kagobutsu taiyo denchi no seizo gijutsu kaihatsu (shuhen yoso gijutsu ni kansuru chosa kenkyu - shinhatsuden soshi kozo taiyo denchi kaitaku no chosa kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The present state and trend are surveyed of organic ferroelectric thin films, new carbon materials, fullerene compounds, and thermophotovoltaic (TPV) power. In the study of organic ferroelectric thin-film solar cells, the effort still remains at the basic stage, with the conversion rate as low as 3% in Europe and 2% in Japan. The progress of basic studies, however, is worth attention. It is deemed that 15% is the photoconversion rate to be currently expected from new carbon material solar cells. Fullerene compounds include some semiconductors whose bandgap values may be controlled across a 0.75-1.95eV range, and they may find their place in thin-film solar cells. However, their physical properties are not fully known, and their development into devices such as solar cells is scarcely reported. The research and development of TPV in the U.S. is led by NASA (National Aeronautics and Space Administration) and NREL (National Renewable Energy Laboratory), with their efforts concentrated on the development of portable power sources utilizing combustion heat. In Europe, TPV application to small-scale residential cogeneration systems is under study. (NEDO)

Sunlight absorption engineering for thermophotovoltaics: contributions from the optical design.

Science.gov (United States)

Míguez, Hernán

2015-03-01

Nowadays, solar thermophotovoltaic systems constitute a platform in which sophisticated optical material designs are put into practice with the aim of achieving the long sought after dream of developing an efficient energy conversion device based on this concept. Recent advances demonstrate that higher efficiencies are at reach using photonic nanostructures amenable to mass production and scale-up. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Germanium Back Contact Type Thermophotovoltaic Cell

International Nuclear Information System (INIS)

Nagashima, Tomonori; Okumura, Kenichi; Yamaguchi, Masafumi

2007-01-01

A Ge back contact type photovoltaic cell has been proposed to reduce resistance loss for high current densities in thermophotovoltaic systems. The back contact structure requires less surface recombination velocities than conventional structures with front grid contacts. A SiO2/SiNx double anti-reflection coating including a high refractive index SiNx layer was studied. The SiNx layer has an enough passivation effect to obtain high efficiency. The quantum efficiency of the Ge cell was around 0.8 in the 800-1600 nm wavelength range. The conversion efficiency for infrared lights was estimated at 18% for a blackbody surface and 25% for a selective emitter by using the quantum efficiency and a simulation analysis

Performance of ultra high efficiency thin germanium p-n junction solar cells intended for solar thermophotovoltaic application

Energy Technology Data Exchange (ETDEWEB)

Vera, E S; Loferski, J J; Spitzer, M; Schewchun, J

1981-01-01

The theoretical upper limit conversion efficiency as a function of cell thickness and junction position is calculated for a germanium p-n junction solar cell intended for solar thermophotovoltaic energy conversion which incorporates minority carrier mirrors and optical mirrors on both the front and back boundaries of the active part of the device. The optical mirrors provide light confinement reducing the thickness required for optimum performance while minority carrier mirrors diminish surface recombination of carriers which seriously reduce short circuit current and limit open circuit voltage. The role of non-ideal optical and minority carrier mirrors and the effect of resistivity variations are studied. The calculations are conducted under conditions of high incident power (2-25 W/cm/sup 2/) which are encountered in solar thermophotovoltaic energy conversion systems. 14 refs.

Thermodynamic limits of energy harvesting from outgoing thermal radiation.

Science.gov (United States)

Buddhiraju, Siddharth; Santhanam, Parthiban; Fan, Shanhui

2018-04-17

We derive the thermodynamic limits of harvesting power from the outgoing thermal radiation from the ambient to the cold outer space. The derivations are based on a duality relation between thermal engines that harvest solar radiation and those that harvest outgoing thermal radiation. In particular, we derive the ultimate limit for harvesting outgoing thermal radiation, which is analogous to the Landsberg limit for solar energy harvesting, and show that the ultimate limit far exceeds what was previously thought to be possible. As an extension of our work, we also derive the ultimate limit of efficiency of thermophotovoltaic systems.

Development of a small air-cooled ``midnight sun'' thermophotovoltaic electric generator

Science.gov (United States)

Fraas, Lewis M.; Xiang, Huang Han; Hui, She; Ferguson, Luke; Samaras, John; Ballantyne, Russ; Seal, Michael; West, Ed

1996-02-01

A natural gas fired thermophotovoltaic generator using infrared-sensitive GaSb cells and a silicon carbide emitter is described. The emitter is designed to operate at 1400 °C. Twelve GaSb receivers surround the emitter. Each receiver contains a string of series connected cells. Special infrared filters are bonded to each cell. These filters transmit short wavelength useful IR to the cells while reflecting longer wavelength IR back to the emitter. Combustion air is supplied to the burner through a counterflow heat exchanger where the air is preheated by the exhaust from the burner. The unit is air cooled and designed to produce approximately 100 Watts of electric power.

Fiscal 1998 New Sunshine Program achievement report. Development for practical application of photovoltaic system - Development of ultrahigh-efficiency crystalline compound solar cell manufacturing technology - Research and survey of peripheral element technologies (Research and survey for development of solar cell of new power generation device structure); 1998 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu seika hokokusho. Chokokoritsu kessho kagobutsu taiyo denchi no seizo gijutsu kaihatsu / shuhen yoso gijutsu ni kansuru chosa kenkyu (shinhatsuden soshi kozo taiyo denchi kaitaku no chosa kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Attention is paid to behavior at the molecular level with reference taken to the photosynthetic mechanism, and a behavioral mechanism is proposed, which incorporates, in place of the conventional band model, a concept of a molecular structure based on electron transfer, excitation energy transfer, and reactions of oxidation and reduction. Discussion is then made on elements of technology development for the embodiment of high-efficiency organic ferroelectric thin-film solar cells. The elements taken up include the feasibility of organic ferroelectric thin-film cells, photoelctric conversion systems of plants and photosynthetic bacteria, solar cells using donor-acceptor type dyes, organic thin-film solar cells using conductive polymers, and efficient photoexcitation of organic dyes. Fullerene compounds are semiconductive and their band gaps may be controlled to stay within the range of 0.75-1.9eV, and this justifies a hope that they will serve as solar cells. As for TPV (thermophotovoltaic) conversion, it is under development mainly at NASA (National Aeronautics and Space Administration) as a transportable power source based on heat of combustion. Efforts are also being exerted since 1990 in five European countries to develop TPV systems for small-scale cogeneration. (NEDO)

Performance evaluation of thermophotovoltaic GaSb cell technology in high temperature waste heat

Science.gov (United States)

Utlu, Z.; Önal, B. S.

2018-02-01

In this study, waste heat was evaluated and examined by means of thermophotovoltaic systems with the application of energy production potential GaSb cells. The aim of our study is to examine GaSb cell technology at high temperature waste heat. The evaluation of the waste heat to be used in the system is designed to be used in the electricity, industry and iron and steel industry. Our work is research. Graphic analysis is done with Matlab program. The high temperature waste heat graphs applied on the GaSb cell are in the results section. Our study aims to provide a source for future studies.

Radiative sky cooling: fundamental physics, materials, structures, and applications

Science.gov (United States)

Sun, Xingshu; Sun, Yubo; Zhou, Zhiguang; Alam, Muhammad Ashraful; Bermel, Peter

2017-07-01

Radiative sky cooling reduces the temperature of a system by promoting heat exchange with the sky; its key advantage is that no input energy is required. We will review the origins of radiative sky cooling from ancient times to the modern day, and illustrate how the fundamental physics of radiative cooling calls for a combination of properties that may not occur in bulk materials. A detailed comparison with recent modeling and experiments on nanophotonic structures will then illustrate the advantages of this recently emerging approach. Potential applications of these radiative cooling materials to a variety of temperature-sensitive optoelectronic devices, such as photovoltaics, thermophotovoltaics, rectennas, and infrared detectors, will then be discussed. This review will conclude by forecasting the prospects for the field as a whole in both terrestrial and space-based systems.

Performance evaluation and parametric optimum design of a molten carbonate fuel cell-thermophotovoltaic cell hybrid system

International Nuclear Information System (INIS)

Yang, Zhimin; Liao, Tianjun; Zhou, Yinghui; Lin, Guoxing; Chen, Jincan

2016-01-01

Highlights: • A molten carbonate fuel cell-thermophotovoltaic cell hybrid system is established. • The performance characteristics of the hybrid system are systematically evaluated. • The optimal regions of the power output density and efficiency are determined. • The values of key parameters at the maximum power output density are calculated. • The proposed system is proved to have advantages over other hybrid systems. - Abstract: A new model of the hybrid system composed of a molten carbonate fuel cell (MCFC) and a thermophotovoltaic cell (TPVC) is proposed to recovery the waste heat produced by the MCFC. Expressions for the power output and the efficiency of the hybrid system are analytically derived. The performance characteristics of the hybrid system are evaluated. It is found that when the current density of the MCFC, voltage output of the TPVC, electrode area ratio of the MCFC to the TPVC, and energy gap of the material in the photovoltaic cell are optimally chosen, the maximum power output density of the hybrid system is obviously larger than that of the single MCFC. Moreover, the improved percentages of the maximum power output density of the proposed model relative to that of the single MCFC are calculated for differently operating temperatures of the MCFC and are compared with those of some MCFC-based hybrid systems reported in the literature, and consequently, the advantages of the MCFC-TPVC hybrid system are revealed.

Special Issue on the Second International Workshop on Micro- and Nano-Scale Thermal Radiation

Science.gov (United States)

Zhang, Zhuomin; Liu, Linhua; Zhu, Qunzhi; Mengüç, M. Pinar

2015-06-01

Micro- and nano-scale thermal radiation has become one of the fastest growing research areas because of advances in nanotechnology and the development of novel materials. The related research and development includes near-field radiation transfer, spectral and directional selective emitters and receivers, plasmonics, metamaterials, and novel nano-scale fabrication techniques. With the advances in these areas, important applications in energy harvesting such as solar cells and thermophotovoltaics, nanomanufacturing, biomedical sensing, thermal imaging as well as data storage with the localized heating/cooling have been pushed to higher levels.

Conversion of NIR-radiation to Electric Power in a Solar Greenhouse

Science.gov (United States)

Sonneveld, P. J.; Swinkels, G. L. A. M.; Bot, G. P. A.; Flamand, G.

2007-02-01

The scope of this investigation is the development of a new type of greenhouse with an integrated filter for rejecting near infrared radiation (NIR) and a solar energy delivery system. Cooled greenhouses are an important issue to cope with the combination of high global radiation and high outdoor temperatures. As a first measure, the spectral selective cover material, which prevents the entrance of NIR radiation, is investigated. The special spectral selective reflectivity of these materials has to block up to 50% of the solar energy outside the greenhouse, which will reduce the needed cooling capacity. The second measure is the integration of a solar energy system. When the NIR reflecting coating is designed as a parabolic or circular shaped reflector integrated in the greenhouse, the reflected solar energy of a PV cell in the focus point delivers electric energy. With a ray tracing computer program the geometry of the reflector was optimally designed with respect to the maximum power level. The PV or TPV cells mounted in the focal point require cooling due to the high heat load of the concentrated radiation (concentration factor of 40-80). The properties of different materials, Ge, GaSb, CIS and Si cells were investigated to find the optimal cell for this application. For the second option a tubular collector is placed in the focus of the reflector. The collector contains thermal oil, which is heated up to a temperature of 400°C. This hot oil can be used for heating a Stirling motor or an Organic Rankine Cycle (ORC). The typical efficiencies and economic achievement of these systems including the tube collector are compared with the efficiencies of the TPV cells.

Examination of thermophotovoltaic GaSb cell technology in low and medium temperatures waste heat

Science.gov (United States)

Utlu, Z.; Önal, B. S.

2018-02-01

In this study, waste heat was evaluated and examined by means of thermophotovoltaic systems with the application of energy production potential GaSb cells. The aim of our study is to examine GaSb cell technology at low and medium temperature waste heat. The evaluation of the waste heat to be used in the system is designed to be used in the electricity, industry and iron and steel industry. Our work is research. Graphic analysis is done with Matlab program. The low and medium temperature waste heat graphs applied on the GaSb cell are in the results section. Our study aims to provide a source for future studies.

Radiative sky cooling: fundamental physics, materials, structures, and applications

Directory of Open Access Journals (Sweden)

Sun Xingshu

2017-07-01

Full Text Available Radiative sky cooling reduces the temperature of a system by promoting heat exchange with the sky; its key advantage is that no input energy is required. We will review the origins of radiative sky cooling from ancient times to the modern day, and illustrate how the fundamental physics of radiative cooling calls for a combination of properties that may not occur in bulk materials. A detailed comparison with recent modeling and experiments on nanophotonic structures will then illustrate the advantages of this recently emerging approach. Potential applications of these radiative cooling materials to a variety of temperature-sensitive optoelectronic devices, such as photovoltaics, thermophotovoltaics, rectennas, and infrared detectors, will then be discussed. This review will conclude by forecasting the prospects for the field as a whole in both terrestrial and space-based systems.

Design of broadband absorber using 2-D materials for thermo-photovoltaic cell application

Science.gov (United States)

Agarwal, Sajal; Prajapati, Y. K.

2018-04-01

Present study is done to analyze a nano absorber for thermo-photovoltaic cell application. Optical absorbance of two-dimensional materials is exploited to achieve high absorbance. It is found that few alternating layers of graphene/transition metal dichalcogenide provide high absorbance of electromagnetic wave in visible as well as near infrared region. Four transition metal dichalcogenides are considered and found that most of these provide perfect absorbance for almost full considered wavelength range i.e. 200-1000 nm. Demonstrated results confirm the extended operating region and improved absorbance of the proposed absorber in comparison to the existing absorbers made of different materials. Further, absorber performance is improved by using thin layers of gold and chromium. Simple geometry of the proposed absorber also ensures easy fabrication.

Enhancing radiative energy transfer through thermal extraction

Directory of Open Access Journals (Sweden)

Tan Yixuan

2016-06-01

Full Text Available Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a. In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics.

Advanced radioisotope power source options for Pluto Express

International Nuclear Information System (INIS)

Underwood, M.L.

1995-01-01

In the drive to reduce mass and cost, Pluto Express is investigating using an advanced power conversion technology in a small Radioisotope Power Source (RPS) to deliver the required mission power of 74 W(electric) at end of mission. Until this year the baseline power source under consideration has been a Radioisotope Thermoelectric Generator (RTG). This RTG would be a scaled down GPHS RTG with an inventory of 6 General Purpose Heat Sources (GPHS) and a mass of 17.8 kg. High efficiency, advanced technology conversion options are being examined to lower the power source mass and to reduce the amount of radioisotope needed. Three technologies are being considered as the advanced converter technology: the Alkali Metal Thermal-to-Electric Converter (AMTEC), Thermophotovoltaic (TPV) converters, and Stirling Engines. Conceptual designs for each of these options have been prepared. Each converter would require only 2 GPHSs to provide the mission power and would have a mass of 6.1, 7.2, and 12.4 kg for AMTEC, TPV, and Stirling Engines respectively. This paper reviews the status of each technology and the projected performance of an advanced RPS based on each technology. Based on the projected performance and spacecraft integration issues, Pluto Express would prefer to use the AMTEC based RPS. However, in addition to technical performance, selection of a power technology will be based on many other factors

Effect of updated data base and improved analysis on performance of radioisotope thermophotovoltaic converter

International Nuclear Information System (INIS)

Schock, A.; Or, C.T.

1996-01-01

Previous analyses of RTPV space power systems published by the authors were based on a number of approximations employed to permit early dissemination of preliminary results pending availability of fuller experimental data need3d to conduct more rigorous analyses. Among those approximations were: (1) the use of limited test data and optimistic projections of the spectral transmissivity of the RTPV's selective IR filters and of the spectral quantum efficiency of the GaSb PV cells; (2) the use of theoretical formulas instead of experimental measurements of the PV cell's open-circuit voltage, fill factor, and optimum voltage instead of its measured current-voltage characteristics; (3) rough estimates of the TPV converter's active-area fraction instead of computed values based on detailed designs; (4) inadequate accounting for the effect of radiation reflected by the IR filter and absorbed by the emitter in reducing the generator's required heat input; and (5) omission of the shadowing effect and ohmic losses caused by the PV cell's grid lines. The above-listed shortcomings of the previously published analyses are addressed in the present paper, which describes revised analyses based on recently obtained experimental data of IR filter reflectivities and PV cell quantum efficiencies and current-voltage characteristic, measured by EDTEK under an OSC-initiated subcontract to its ongoing DOE contract. Their test results show that EDTEK has been eminently successful in improving the reflectivities of the IR filters and in reproducing the quantum efficiencies of Boeing's best PV cells, but their initial (Dec-95) PV cell fell far short of matching the open-circuit voltages and fill factors predicted by theory

Finite element analysis of ARPS structures

International Nuclear Information System (INIS)

Ruhkamp, J.D.; McDougal, J.R.; Kramer, D.P.

1998-01-01

Algor finite element software was used to determine the stresses and deflections in the metallic walls of Advanced Radioisotope Power Systems (ARPS) designs. The preliminary design review of these systems often neglects the structural integrity of the design which can effect fabrication and the end use of the design. Before finite element analysis (FEA) was run on the canister walls of the thermophotovoltaic (TPV) generator, hand calculations were used to approximate the stresses and deflections in a flat plate. These results compared favorably to the FEA results of a similar size flat plate. The AMTEC (Alkali Metal Thermal-to-Electric Conversion) cells were analyzed by FEA and the results compared to two cells that were mechanically tested. The mechanically tested cells buckled in the thin sections, one at the top and one in the lower section. The FEA predicted similar stress and shape results but the critical buckling load was found to be very shape dependent

Rare Earth Garnet Selective Emitter

Science.gov (United States)

Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

1994-01-01

Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional

Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

International Nuclear Information System (INIS)

Ito, Kota; Miura, Atsushi; Iizuka, Hideo; Toshiyoshi, Hiroshi

2015-01-01

Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics

Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

Energy Technology Data Exchange (ETDEWEB)

Ito, Kota, E-mail: kotaito@mosk.tytlabs.co.jp [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Miura, Atsushi; Iizuka, Hideo [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Toshiyoshi, Hiroshi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

2015-02-23

Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics.

Radiative heat transfer in the extreme near field.

Science.gov (United States)

Kim, Kyeongtae; Song, Bai; Fernández-Hurtado, Víctor; Lee, Woochul; Jeong, Wonho; Cui, Longji; Thompson, Dakotah; Feist, Johannes; Reid, M T Homer; García-Vidal, Francisco J; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

2015-12-17

Radiative transfer of energy at the nanometre length scale is of great importance to a variety of technologies including heat-assisted magnetic recording, near-field thermophotovoltaics and lithography. Although experimental advances have enabled elucidation of near-field radiative heat transfer in gaps as small as 20-30 nanometres (refs 4-6), quantitative analysis in the extreme near field (less than 10 nanometres) has been greatly limited by experimental challenges. Moreover, the results of pioneering measurements differed from theoretical predictions by orders of magnitude. Here we use custom-fabricated scanning probes with embedded thermocouples, in conjunction with new microdevices capable of periodic temperature modulation, to measure radiative heat transfer down to gaps as small as two nanometres. For our experiments we deposited suitably chosen metal or dielectric layers on the scanning probes and microdevices, enabling direct study of extreme near-field radiation between silica-silica, silicon nitride-silicon nitride and gold-gold surfaces to reveal marked, gap-size-dependent enhancements of radiative heat transfer. Furthermore, our state-of-the-art calculations of radiative heat transfer, performed within the theoretical framework of fluctuational electrodynamics, are in excellent agreement with our experimental results, providing unambiguous evidence that confirms the validity of this theory for modelling radiative heat transfer in gaps as small as a few nanometres. This work lays the foundations required for the rational design of novel technologies that leverage nanoscale radiative heat transfer.

Near-field radiation between graphene-covered carbon nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Zhang, Richard Z.; Liu, Xianglei; Zhang, Zhuomin M., E-mail: zhuomin.zhang@me.gatech.edu [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2015-05-15

It has been shown that at small separation distances, thermal radiation between hyperbolic metamaterials is enhanced over blackbodies. This theoretical study considers near-field radiation when graphene is covered on the surfaces of two semi-infinite vertically aligned carbon nanotube (VACNT) arrays separated by a sub-micron vacuum gap. Doped graphene is found to improve photon tunneling in a broad hyperbolic frequency range, due to the interaction with graphene-graphene surface plasmon polaritons (SPP). In order to elucidate the SPP resonance between graphene on hyperbolic substrates, vacuum-suspended graphene sheets separated by similar gap distances are compared. Increasing the Fermi energy through doping shifts the spectral heat flux peak toward higher frequencies. Although the presence of graphene on VACNT does not offer huge near-field heat flux enhancement over uncovered VACNT, this study identifies conditions (i.e., gap distance and doping level) that best utilize graphene to augment near-field radiation. Through the investigation of spatial Poynting vectors, heavily doped graphene is found to increase penetration depths in hyperbolic modes and the result is sensitive to the frequency regime. This study may have an impact on designing carbon-based vacuum thermophotovoltaics and thermal switches.

ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood

2004-04-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

Radiative heat transfer exceeding the blackbody limit between macroscale planar surfaces separated by a nanosize vacuum gap

Science.gov (United States)

Bernardi, Michael P.; Milovich, Daniel; Francoeur, Mathieu

2016-09-01

Using Rytov's fluctuational electrodynamics framework, Polder and Van Hove predicted that radiative heat transfer between planar surfaces separated by a vacuum gap smaller than the thermal wavelength exceeds the blackbody limit due to tunnelling of evanescent modes. This finding has led to the conceptualization of systems capitalizing on evanescent modes such as thermophotovoltaic converters and thermal rectifiers. Their development is, however, limited by the lack of devices enabling radiative transfer between macroscale planar surfaces separated by a nanosize vacuum gap. Here we measure radiative heat transfer for large temperature differences (~120 K) using a custom-fabricated device in which the gap separating two 5 × 5 mm2 intrinsic silicon planar surfaces is modulated from 3,500 to 150 nm. A substantial enhancement over the blackbody limit by a factor of 8.4 is reported for a 150-nm-thick gap. Our device paves the way for the establishment of novel evanescent wave-based systems.

Bridgman growth and characterization of bulk single crystals of Ga1-xInxSb for thermophotovoltaic applications

International Nuclear Information System (INIS)

Boyer, J.R.; Haines, W.T.

1997-12-01

Thermophotovoltaic generation of electricity is attracting renewed attention due to recent advances in low bandgap (0.5--0.7 eV) III-V semiconductors. The use of mixed pseudo-binary compounds allows for the tailoring of the lattice parameter and the bandgap of the material. Conventional deposition techniques (i.e., epitaxy) for producing such ternary or quaternary materials are typically slow and expensive. Production of bulk single crystals of ternary materials, for example Ga 1-x In x Sb, is expected to dramatically reduce such material costs. Bulk single crystals of Ga 1-x In x Sb have been prepared using a Bridgman technique in a two-zone furnace. These crystals are 19 mm in diameter by approximately 50 mm long and were produced using seeds of the same diameter. The effects of growth rate and starting materials on the composition and quality of these crystals will be discussed and compared with other attempts to produce single crystals of this material

Overcoming black body radiation limit in free space: metamaterial superemitter

Science.gov (United States)

Maslovski, Stanislav I.; Simovski, Constantin R.; Tretyakov, Sergei A.

2016-01-01

Here, we demonstrate that the power spectral density of thermal radiation at a specific wavelength produced by a body of finite dimensions set up in free space under a fixed temperature could be made theoretically arbitrary high, if one could realize double negative metamaterials with arbitrary small loss and arbitrary high absolute values of permittivity and permeability (at a given frequency). This result refutes the widespread belief that Planck’s law itself sets a hard upper limit on the spectral density of power emitted by a finite macroscopic body whose size is much greater than the wavelength. Here we propose a physical realization of a metamaterial emitter whose spectral emissivity can be greater than that of the ideal black body under the same conditions. Due to the reciprocity between the heat emission and absorption processes such cooled down superemitter also acts as an optimal sink for the thermal radiation—the ‘thermal black hole’—which outperforms Kirchhoff-Planck’s black body which can absorb only the rays directly incident on its surface. The results may open a possibility to realize narrowband super-Planckian thermal radiators and absorbers for future thermo-photovoltaic systems and other devices.

Overcoming black body radiation limit in free space: metamaterial superemitter

International Nuclear Information System (INIS)

Maslovski, Stanislav I; Simovski, Constantin R; Tretyakov, Sergei A

2016-01-01

Here, we demonstrate that the power spectral density of thermal radiation at a specific wavelength produced by a body of finite dimensions set up in free space under a fixed temperature could be made theoretically arbitrary high, if one could realize double negative metamaterials with arbitrary small loss and arbitrary high absolute values of permittivity and permeability (at a given frequency). This result refutes the widespread belief that Planck’s law itself sets a hard upper limit on the spectral density of power emitted by a finite macroscopic body whose size is much greater than the wavelength. Here we propose a physical realization of a metamaterial emitter whose spectral emissivity can be greater than that of the ideal black body under the same conditions. Due to the reciprocity between the heat emission and absorption processes such cooled down superemitter also acts as an optimal sink for the thermal radiation—the ‘thermal black hole’—which outperforms Kirchhoff–Planck’s black body which can absorb only the rays directly incident on its surface. The results may open a possibility to realize narrowband super-Planckian thermal radiators and absorbers for future thermo-photovoltaic systems and other devices. (paper)

Comportamento sob fluência em elastômeros termoplásticos vulcanizados baseados em poliamida 6 e borracha nitrílica Creep behavior of polyamide 6/nitrylic rubber TPV's blends

Directory of Open Access Journals (Sweden)

Ana C. O. Gomes

2009-01-01

Full Text Available Os materiais testados neste trabalho são o resultado de um estudo do uso de aditivos e compatibilizantes na mistura de poliamida 6 (PA6 e borracha nitrílica (NBR, realizado com o objetivo de melhorar suas propriedades mecânicas e facilitar o processamento da mistura. Fluência ("creep" é um teste mecânico importante ao simular a aplicação final do material de engenharia, possibilitando a previsão do desempenho de modo comparativo. Entretanto, é um teste pouco explorado na caracterização de TPV's. A melhora nas propriedades com a adição de aditivos e a eficiência do processo de compatibilização pode ser observada através da variação na compliância das amostras analisadas. Os resultados são correlacionados usando testes de densidade, teor de gel, resistência à tração e microscopia eletrônica de varredura. O presente trabalho mostra que é possível avaliar um material em condições semelhantes à aplicação final em um teste rápido e com gasto mínimo de material.The materials tested in this work are the result of a study involving the use of additives and compatibilization in blends of PA6 and NBR, which was aimed at enhancing the mechanical properties and processability of the blend. Creep is an important mechanical test since it simulates the final application of the material, allowing a prediction of material performance, in a comparative way. However, this is a test seldom explored in the characterization of TPV's. The enhancement of the properties induced by additives and the efficiency of compatibilization process can be observed through the analysis of changes in the compliance of the samples. The results are correlated using measurements of density, gel content, tension strength and scanning electron microscopy. The present work shows it to be possible to evaluate a material under conditions similar to those in the final applications, in a fast test and with minimal material waste.

Short communication: Phenotypic protease inhibitor resistance and cross-resistance in the clinic from 2006 to 2008 and mutational prevalences in HIV from patients with discordant tipranavir and darunavir susceptibility phenotypes.

Science.gov (United States)

Bethell, Richard; Scherer, Joseph; Witvrouw, Myriam; Paquet, Agnes; Coakley, Eoin; Hall, David

2012-09-01

To test tipranavir (TPV) or darunavir (DRV) as treatment options for patients with phenotypic resistance to protease inhibitors (PIs), including lopinavir, saquinavir, atazanavir, and fosamprenavir, the PhenoSense GT database was analyzed for susceptibility to DRV or TPV among PI-resistant isolates. The Monogram Biosciences HIV database (South San Francisco, CA) containing 7775 clinical isolates (2006-2008) not susceptible to at least one first-generation PI was analyzed. Phenotypic responses [resistant (R), partially susceptible (PS), or susceptible (S)] were defined by upper and lower clinical cut-offs to each PI. Genotypes were screened for amino acid substitutions associated with TPV-R/DRV-S and TPV-S/DRV-R phenotypes. In all, 4.9% (378) of isolates were resistant to all six PIs and 31.0% (2407) were resistant to none. Among isolates resistant to all four first-generation PIs, DRV resistance increased from 21.2% to 41.9% from 2006 to 2008, respectively, and resistance to TPV remained steady (53.9 to 57.3%, respectively). Higher prevalence substitutions in DRV-S/TPV-R isolates versus DRV-R/TPV-S isolates, respectively, were 82L/T (44.4% vs. 0%) and 83D (5.8% vs. 0%). Higher prevalence substitutions in DRV-R/TPV-S virus were 50V (0.0% vs. 28.9%), 54L (1.0% vs. 36.1%), and 76V (0.4% vs. 15.5%). Mutations to help predict discordant susceptibility to DRV and TPV in isolates with reduced susceptibility to other PIs were identified. DRV resistance mutations associated with improved virologic response to TPV were more prevalent in DRV-R/TPV-S isolates. TPV resistance mutations were more prevalent in TPV-R and DRV-S isolates. These results confirm the impact of genotype on phenotype, illustrating how HIV genotype and phenotype data assist regimen optimization.

Combustion and direct energy conversion inside a micro-combustor

International Nuclear Information System (INIS)

Lei, Yafeng; Chen, Wei; Lei, Jiang

2016-01-01

Highlights: • The flammability range of micro-combustor was broadened with heat recirculation. • The quenching diameter decreased with heat recirculation compared to without recirculation. • The surface areas to volume ratio was the most important parameter affecting the energy conversion efficiency. • The maximum conversion efficiency (3.15%) was achieved with 1 mm inner diameter. - Abstract: Electrical energy can be generated by employing a micro-thermophotovoltaic (TPV) cell which absorbs thermal radiation from combustion taking place in a micro-combustor. The stability of combustion in a micro-combustor is essential for operating a micro-power system using hydrogen and hydrocarbon fuels as energy source. To understand the mechanism of sustaining combustion within the quenching distance of fuel, this study proposed an annular micro combustion tube with recirculation of exhaust heat. To explore the feasibility of combustion in the micro annular tube, the parameters influencing the combustion namely, quenching diameter, and flammability were studied through numerical simulation. The results indicated that combustion could be realized in micro- combustor using heat recirculation. Following results were obtained from simulation. The quenching diameter reduced from 1.3 mm to 0.9 mm for heat recirculation at equivalence ratio of 1; the lean flammability was 2.5%–5% lower than that of without heat recirculation for quenching diameters between 2 mm and 5 mm. The overall energy conversion efficiency varied at different inner diameters. A maximum efficiency of 3.15% was achieved at an inner diameter of 1 mm. The studies indicated that heat recirculation is an effective strategy to maintain combustion and to improve combustion limits in micro-scale system.

Coupling of near-field thermal radiative heating and phonon Monte Carlo simulation: Assessment of temperature gradient in n-doped silicon thin film

International Nuclear Information System (INIS)

Wong, Basil T.; Francoeur, Mathieu; Bong, Victor N.-S.; Mengüç, M. Pinar

2014-01-01

Near-field thermal radiative exchange between two objects is typically more effective than the far-field thermal radiative exchange as the heat flux can increase up to several orders higher in magnitudes due to tunneling of evanescent waves. Such an interesting phenomenon has started to gain its popularity in nanotechnology, especially in nano-gap thermophotovoltaic systems and near-field radiative cooling of micro-/nano-devices. Here, we explored the existence of thermal gradient within an n-doped silicon thin film when it is subjected to intensive near-field thermal radiative heating. The near-field radiative power density deposited within the film is calculated using the Maxwell equations combined with fluctuational electrodynamics. A phonon Monte Carlo simulation is then used to assess the temperature gradient by treating the near-field radiative power density as the heat source. Results indicated that it is improbable to have temperature gradient with the near-field radiative heating as a continuous source unless the source comprises of ultra-short radiative pulses with a strong power density. - Highlights: • This study investigates temperature distribution in an n-doped silicon thin film. • Near-field radiative heating is treated as a volumetric phenomenon. • The temperature gradient is computed using phonon MC simulation. • Temperature of thin film can be approximated as uniform for radiation calculations. • If heat source is a pulsed radiation, a temperature gradient can be established

Image quality of mean temporal arterial and mean temporal portal venous phase images calculated from low dose dynamic volume perfusion CT datasets in patients with hepatocellular carcinoma and pancreatic cancer

Energy Technology Data Exchange (ETDEWEB)

Wang, X. [Radiology Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China); Henzler, T., E-mail: thomas.henzler@medma.uni-heidelberg.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Gawlitza, J.; Diehl, S. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Wilhelm, T. [Department of Surgery, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Schoenberg, S.O. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Jin, Z.Y.; Xue, H.D. [Radiology Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China); Smakic, A. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

2016-11-15

Purpose: Dynamic volume perfusion CT (dVPCT) provides valuable information on tissue perfusion in patients with hepatocellular carcinoma (HCC) and pancreatic cancer. However, currently dVPCT is often performed in addition to conventional CT acquisitions due to the limited morphologic image quality of dose optimized dVPCT protocols. The aim of this study was to prospectively compare objective and subjective image quality, lesion detectability and radiation dose between mean temporal arterial (mTA) and mean temporal portal venous (mTPV) images calculated from low dose dynamic volume perfusion CT (dVPCT) datasets with linearly blended 120-kVp arterial and portal venous datasets in patients with HCC and pancreatic cancer. Materials and methods: All patients gave written informed consent for this institutional review board–approved HIPAA compliant study. 27 consecutive patients (18 men, 9 women, mean age, 69.1 years ± 9.4) with histologically proven HCC or suspected pancreatic cancer were prospectively enrolled. The study CT protocol included a dVPCT protocol performed with 70 or 80 kVp tube voltage (18 spiral acquisitions, 71.2 s total acquisition times) and standard dual-energy (90/150 kVpSn) arterial and portal venous acquisition performed 25 min after the dVPCT. The mTA and mTPV images were manually reconstructed from the 3 to 5 best visually selected single arterial and 3 to 5 best single portal venous phases dVPCT dataset. The linearly blended 120-kVp images were calculated from dual-energy CT (DECT) raw data. Image noise, SNR, and CNR of the liver, abdominal aorta (AA) and main portal vein (PV) were compared between the mTA/mTPV and the linearly blended 120-kVp dual-energy arterial and portal venous datasets, respectively. Subjective image quality was evaluated by two radiologists regarding subjective image noise, sharpness and overall diagnostic image quality using a 5-point Likert Scale. In addition, liver lesion detectability was performed for each liver

Image quality of mean temporal arterial and mean temporal portal venous phase images calculated from low dose dynamic volume perfusion CT datasets in patients with hepatocellular carcinoma and pancreatic cancer

International Nuclear Information System (INIS)

Wang, X.; Henzler, T.; Gawlitza, J.; Diehl, S.; Wilhelm, T.; Schoenberg, S.O.; Jin, Z.Y.; Xue, H.D.; Smakic, A.

2016-01-01

Purpose: Dynamic volume perfusion CT (dVPCT) provides valuable information on tissue perfusion in patients with hepatocellular carcinoma (HCC) and pancreatic cancer. However, currently dVPCT is often performed in addition to conventional CT acquisitions due to the limited morphologic image quality of dose optimized dVPCT protocols. The aim of this study was to prospectively compare objective and subjective image quality, lesion detectability and radiation dose between mean temporal arterial (mTA) and mean temporal portal venous (mTPV) images calculated from low dose dynamic volume perfusion CT (dVPCT) datasets with linearly blended 120-kVp arterial and portal venous datasets in patients with HCC and pancreatic cancer. Materials and methods: All patients gave written informed consent for this institutional review board–approved HIPAA compliant study. 27 consecutive patients (18 men, 9 women, mean age, 69.1 years ± 9.4) with histologically proven HCC or suspected pancreatic cancer were prospectively enrolled. The study CT protocol included a dVPCT protocol performed with 70 or 80 kVp tube voltage (18 spiral acquisitions, 71.2 s total acquisition times) and standard dual-energy (90/150 kVpSn) arterial and portal venous acquisition performed 25 min after the dVPCT. The mTA and mTPV images were manually reconstructed from the 3 to 5 best visually selected single arterial and 3 to 5 best single portal venous phases dVPCT dataset. The linearly blended 120-kVp images were calculated from dual-energy CT (DECT) raw data. Image noise, SNR, and CNR of the liver, abdominal aorta (AA) and main portal vein (PV) were compared between the mTA/mTPV and the linearly blended 120-kVp dual-energy arterial and portal venous datasets, respectively. Subjective image quality was evaluated by two radiologists regarding subjective image noise, sharpness and overall diagnostic image quality using a 5-point Likert Scale. In addition, liver lesion detectability was performed for each liver

Fiscal 1999 research and development of technologies for practical application of photovoltaic power generation systems. Development of ultrahigh-efficiency crystalline compound solar cell manufacturing technology (Survey of peripheral element technologies - Survey of environmental adaptation of next-generation solar cell development); 1999 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu seika hokokusho. Chokokoritsu kessho kagobutsu taiyo denchi no seizo gijutsu kaihatsu (shuhen yoso gijutsu ni kansuru chosa kenkyu - jisedai taiyo denchi kaihatsu kankyo tekioka chosa)

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

Surveys are conducted of photovoltaic power system development projects and their utilization in Japan and overseas, and a discussion is made on the progress, technical challenges, effects, and implementation systems relating to the solar cell application technology development project under the New Sunshine Program. Compiled in the report are the results of surveys of the research and development of photovoltaic power systems and their diffusion in the U.S. and European nations, and the research and development strategies for and the trends of the development of various types of solar cells in these countries. The trends of research and development of non-conventional type solar cells are also collected, which include 3 cases of TPV (thermophotovoltaic) devices, 5 cases of new inorganic materials, 1 case of new organic materials, and 4 cases of dye-sensitized solar cells. In relation to the status of resources of crystalline compound-based solar cell materials, raw materials for solar cells other than silicon are taken up, and their reserves, manufacturing methods, quantities yielded and consumed, costs, etc., are surveyed. These are all taken into consideration in discussing the basic approach to the study of future research and development as it ought to be. (NEDO)

Fiscal 1999 research and development of technologies for practical application of photovoltaic power generation systems. Development of ultrahigh-efficiency crystalline compound solar cell manufacturing technology (Survey and research on practical application - Volume 1); 1999 nendo taiyoko hatsauden system jitsuyoka gijutsu kaihatsu seika hokokusho. Chokokoritsu kessho kagobutsu taiyo denchi no seizo gijutsu kaihatsu (jitsuyoka kaiseki ni kansuru chosa kenkyu - 1)

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

A 'Sub-committee for investigation of crystalline compound semiconductor solar cells' was established with the participation of experts from the industrial, bureaucratic, and academic circles to support the manufacture of ultrahigh-efficiency crystalline compound solar cells, and a survey was conducted about technical trends relating to III-V group compound solar cells. In the study of the trends and tasks of the state of the art technology, it is stated that the III-V group compound semiconductor multi-junction solar cell was steadily improving in efficiency, that the InGaP/GaAs 2-junction cell on a Ge substrate and InGaP/GaAs/Ge 3-junction cell in particular were moving toward mass production, and that the target for the 4-junction cell to achieve was 40% or higher in efficiency. For cost reduction, investigations were made into the heteroepitaxial technology, dimensional enlargement, mass production, raw material cost reduction, feasibility of the polycrystalline thin-film technology, light concentration, etc. For efficiency improvement, boundary layer control, structure designs, etc., were studied. Investigations were also conducted into nitride semiconductors, superlattice construction, etc., which related to new materials for thin films. TPV (thermophotovoltaic) power, etc., were reviewed for their practical application. (NEDO)

Enhancing radiative energy transfer through thermal extraction

Science.gov (United States)

Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

2016-06-01

Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

75 FR 81310 - In the Matter of Certain Digital Television Products and Certain Products Containing Same and...

Science.gov (United States)

2010-12-27

... Victory Electronics (Taiwan) Co., Ltd. (``Top Victory Electronics''); and Envision Peripherals, Inc. (``Envision''). Cease-and-desist orders were issued against Vizio, TPV USA, Envision, and SBC. Respondents Vizio, AmTran, TPV Technology, TPV USA, Top Victory Electronics, and Envision appealed to the United...

Effect of Rubber Nanoparticle Agglomeration on Properties of Thermoplastic Vulcanizates during Dynamic Vulcanization

Directory of Open Access Journals (Sweden)

Hanguang Wu

2016-04-01

Full Text Available We previously reported that the dispersed rubber microparticles in ethylene-propylene-diene monomer (EPDM/polypropylene (PP thermoplastic vulcanizates (TPVs are actually agglomerates of rubber nanoparticles. In this study, based on this new understanding of the microstructure of TPV, we further revealed the microstructure-properties relationship of EPDM/PP TPV during dynamic vulcanization, especially the effect of the size of rubber nanoparticle agglomerates (dn, the thicknesses of PP ligaments (IDpoly and the rubber network on the properties of EPDM/PP TPV. We were able to simultaneously obtain a high tensile strength, elongation at break, elastic modulus, and elasticity for the EPDM/PP TPV by the achievement of a smaller dn, a thinner IDpoly and a denser rubber network. Interestingly, the effect of dn and IDpoly on the elastic modulus of EPDM/PP TPV composed of rubber nanoparticle agglomerates is different from that of EPDM/PP TPVs composed of rubber microparticles reported previously. The deformation behavior of the TPVs during stretching was studied to understand the mechanism for the achievement of good mechanical properties. Interestingly, the rubber nanoparticle agglomerates are oriented along the tensile direction during stretching. The TPV samples with smaller and more numerous rubber nanoparticle agglomerates can slow down the development of voids and cracks more effectively, thus leading to increase in tensile strength and elongation at break of the EPDM/PP TPV.

5α-Reductase inhibitor is less effective in men with small prostate volume and low serum prostatic specific antigen level.

Science.gov (United States)

Lin, Victor C; Liao, Chun-Hou; Wang, Chung-Cheng; Kuo, Hann-Chorng

2015-09-01

Large total prostate volumes (TPVs) or high serum prostate-specific antigen (PSA) levels indicate high-risk clinical progression of benign prostatic hyperplasia. This prospective study investigated the treatment outcome of combined 5α-reductase inhibitor and α-blocker in patients with and without large TPVs or high PSA levels. Men aged ≥ 45 years with International Prostate Symptom scores (IPSS) ≥ 8, TPV ≥ 20 mL, and maximum flow rate ≤ 15 mL/s received a combination therapy (dutasteride plus doxaben) for 2 years. Patients with baseline PSA ≥ 4 ng/mL underwent prostatic biopsy for excluding malignancy. The changes in the parameters from baseline to 24 months after combination therapy were compared in those with and without TPV ≥ 40 mL or PSA levels ≥ 1.5 ng/mL. A total of 285 patients (mean age 72 ± 9 years) completed the study. Combination therapy resulted in significant continuous improvement in IPSS, quality of life index, maximum flow rate, and postvoid residual (all p < 0.0001) regardless of baseline TPV or PSA levels. However, only patients with baseline TPV ≥ 40 mL had significant improvements in IPSS-storage subscore, voided volume, reduction in TPV, transitional zone index, and PSA levels. In addition, patients with baseline TPV < 40 mL and PSA < 1.5 ng/mL had neither a reduction in TPV nor a decrease in serum PSA level. A high TPV indicates more outlet resistance, whereas elevated serum PSA level reflects glandular proliferation. Thus, patients with TPV<40 mL and low PSA levels has less benefit from 5α-reductase inhibitor therapy. The therapeutic effect of combined treatment may arise mainly from the α-blocker in these patients. Copyright © 2013. Published by Elsevier B.V.

Tailoring Thermal Radiative Properties with Doped-Silicon Nanowires

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhuomin [Georgia Inst. of Technology, Atlanta, GA (United States)

2017-08-28

tailor the transmittance, reflectance, and absorptance of nanostructured materials. Furthermore, graphene can be used to enhance near-field coupling to increase the phonon tunneling probability. We have performed analysis of near-field thermophotovoltaic devices with backside reflecting mirror and with tungsten gratings. We have predicted a large enhancement of electroluminescent refrigeration at a separation distance down to 10 nm due to near-field thermal radiation effect. A heat flux measurement system is developed to measure the near-field radiation in vacuum. We have fabricated doped Si plates separated by sparsely distributed posts to create a 200-800 nm vacuum gap. Our measurement results demonstrate that 11 times enhancement of near-field thermal radiation between parallel doped-Si plates with a lateral dimension 1 cm by 1 cm.

Graphene-based photovoltaic cells for near-field thermal energy conversion.

Science.gov (United States)

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

Proceedings of the 1998 oil heat technology conference

Energy Technology Data Exchange (ETDEWEB)

McDonald, R.J.

1998-04-01

The 1998 Oil Heat Technology Conference was held on April 7--8 at Brookhaven National Laboratory (BNL) under sponsorship by the US Department of Energy, Office of Building Technologies, State and Community Programs (DOE/BTS). The meeting was held in cooperation with the Petroleum Marketers Association of America (PMAA). Fourteen technical presentations was made during the two-day program, all related to oil-heat technology and equipment, these will cover a range of research, developmental, and demonstration activities being conducted within the United States and Canada, including: integrated oil heat appliance system development in Canada; a miniature heat-actuated air conditioner for distributed space conditioning; high-flow fan atomized oil burner (HFAB) development; progress in the development of self tuning oil burners; application of HFAB technology to the development of a 500 watt; thermophotovoltaic (TPV) power system; field tests of the Heat Wise Pioneer oil burner and Insight Technologies AFQI; expanded use of residential oil burners to reduce ambient ozone and particulate levels by conversion of electric heated homes to oilheat; PMAA`s Oil Heat Technician`s Manual (third edition); direct venting concept development; evolution of the chimney; combating fuel related problems; the effects of red dye and metal contamination on fuel oil stability; new standard for above ground and basement residential fuel oil storage; plastic and steel composite secondary contained tanks; and money left on the table: an economic analysis of tank cleaning.

Advanced conversion technology review panel report

International Nuclear Information System (INIS)

Frazier, T.A.

1998-01-01

The Department of Energy (DOE), the National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory (JPL) established a DOE lead management team and an Advanced Conversion Technology Review Panel. The panel was tasked with providing the management team with an assessment and ranking of the three advanced conversion technologies. The three advanced conversion technologies were alkali metal thermal to electric converter (AMTEC), Stirling engine converter (SEC), and thermophotovoltaic (TPV). To rate and rank these three technologies, five criteria were developed: (1) Performance, (2) Development and Cost/Production and Cost/Schedule Risk, (3) Spacecraft Interface and Operations, (4) Ability to Scale Conversion, and (5) Safety. Discussed are the relative importance of each of these criteria and the rankings of the three advanced conversion technologies. It was the conclusion of the panel that the technology decision should be based on the risk that DOE and NASA are willing to accept. SEC is the most mature technology and would provide the lowest risk option. However, if more risk is acceptable, AMTEC not only provides benefits in the spacecraft interface but is also predicted to outperform the SEC. It was proposed that if AMTEC were selected, funding should be provided at a reasonable level to support back-up technology to be developed in a parallel fashion until AMTEC has proven its capability. The panel report and conclusion were provided to DOE in February 1997

Urinary prostate-specific antigen: predictor of benign prostatic hyperplasia progression?

Science.gov (United States)

Pejcic, Tomislav P; Tulic, Cane Dz; Lalic, Natasa V; Glisic, Biljana D; Ignjatovic, Svetlana D; Markovic, Biljana B; Hadzi-Djokic, Jovan B

2013-04-01

Urinary prostate-specific antigen (uPSA) can be used as additional parameter of benign prostatic hyperplasia (BPH) progression. From January 2001 to December 2011, uPSA was determined in 265 patients with benign prostate. Based on total prostate volume (TPV), the patients with benign prostate were divided in two groups: TPV specificity of 0.83 and sensitivity of 0.67. The level of uPSA reflects prostatic hormonal activity and correlates with TPV, PSA and age. UPSA level ≥ 150 ng/mL can be used as additional predictive parameter of BPH progression.

Association between metabolic syndrome and intravesical prostatic protrusion in patients with benign prostatic enlargement and lower urinary tract symptoms (MIPS Study).

Science.gov (United States)

Russo, Giorgio I; Regis, Federica; Spatafora, Pietro; Frizzi, Jacopo; Urzì, Daniele; Cimino, Sebastiano; Serni, Sergio; Carini, Marco; Gacci, Mauro; Morgia, Giuseppe

2018-05-01

To investigate the association between metabolic syndrome (MetS) and morphological features of benign prostatic enlargement (BPE), including total prostate volume (TPV), transitional zone volume (TZV) and intravesical prostatic protrusion (IPP). Between January 2015 and January 2017, 224 consecutive men aged >50 years presenting with lower urinary tract symptoms (LUTS) suggestive of BPE were recruited to this multicentre cross-sectional study. MetS was defined according to International Diabetes Federation criteria. Multivariate linear and logistic regression models were performed to verify factors associated with IPP, TZV and TPV. Patients with MetS were observed to have a significant increase in IPP (P < 0.01), TPV (P < 0.01) and TZV (P = 0.02). On linear regression analysis, adjusted for age and metabolic factors of MetS, we found that high-density lipoprotein (HDL) cholesterol was negatively associated with IPP (r = -0.17), TPV (r = -0.19) and TZV (r = -0.17), while hypertension was positively associated with IPP (r = 0.16), TPV (r = 0.19) and TZV (r = 0.16). On multivariate logistic regression analysis adjusted for age and factors of MetS, hypertension (categorical; odds ratio [OR] 2.95), HDL cholesterol (OR 0.94) and triglycerides (OR 1.01) were independent predictors of TPV ≥ 40 mL. We also found that HDL cholesterol (OR 0.86), hypertension (OR 2.0) and waist circumference (OR 1.09) were significantly associated with TZV ≥ 20 mL. On age-adjusted logistic regression analysis, MetS was significantly associated with IPP ≥ 10 mm (OR 34.0; P < 0.01), TZV ≥ 20 mL (OR 4.40; P < 0.01) and TPV ≥ 40 mL (OR 5.89; P = 0.03). We found an association between MetS and BPE, demonstrating a relationship with IPP. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Advanced Radiative Emitters for Radioisotope Thermophotovoltaic Power Systems, Phase I

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,...

Device design of GaSb/CdS thin film thermal photovoltaic solar cells%基于GaSb/CdS薄膜热光伏电池的器件设计∗

Institute of Scientific and Technical Information of China (English)

吴限量; 张德贤; 蔡宏琨; 周严; 倪牮; 张建军

2015-01-01

基于GaSb薄膜热光伏器件是降低热光伏系统成本的有效途径之一，本文主要针对GaSb/CdS薄膜热光伏器件结构进行理论分析.采用AFORS-HET软件进行模拟仿真，分析GaSb和CdS两种材料各自的缺陷态密度、界面态对电池性能的影响.根据软件模拟可以得知，吸收层GaSb的缺陷态密度以及GaSb与CdS之间的界面态密度是影响电池性能的重要因素.当GaSb缺陷态增加时，主要影响电池的填充因子，电池效率明显下降.而作为窗口层的CdS缺陷态密度对电池性能影响不明显，当CdS缺陷态密度上升4个数量级时，电池效率仅下降0.11%.%Enthusiasm in the research of thermo-photovoltaic (TPV) cells has been aroused because the low bandwidth semi-conductors of III-V family are coming into use. GaSb, as a member of III-V family, has many merits such as high absorption coeffcient, and low band gap of 0.725 eV at 300 K etc.. At present thermo-photovoltaic cells are usually based on GaSb wafer, and it can be manufactured by the vertical Bridgeman method. Thermo-photovoltaic cell based on GaSb films is one of the effective ways to reduce the cost of the thermo-photovoltaic system. GaSb polycrystalline films can be grown by physical vapor deposition (PVD) which has advantages in using fewer materials and energy, and also in doing little harm to the environment. Because of residual acceptor defects VGaGaSb, GaSb thin film is usually of p-type semiconductor. So we should find n-type semiconductor material to form pn junction. We choose CdS as the emission layer of a cell structure. CdS belongs to n-type semiconductor with a narrow band gap of 2.4 eV and high light transmissivity. CdS thin film grown by chemical bath deposition (CBD) has passivation properties for GaSb. CdS layers can remove native oxides from GaSb surface and reduce the surface recombination velocity of GaSb. This paper focuses on theoretical analysis of GaSb/CdS thin film photovoltaic

Effectiveness of tipranavir versus darunavir as a salvage therapy in HIV-1 treatment-experienced patients.

Science.gov (United States)

Domínguez-Hermosillo, Juan Carlos; Mata-Marin, José Antonio; Herrera-González, Norma Estela; Chávez-García, Marcelino; Huerta-García, Gloria; Nuñez-Rodríguez, Nohemí; García-Gámez, José Gerardo; Jiménez-Romero, Anai; Gaytán-Martínez, Jesús Enrique

2016-09-30

Although both tipranavir (TPV) and darunavir (DRV) represent important options for the management of patients with multi-protease inhibitor (PI)-resistant human immunodeficiency virus (HIV), currently there are no studies comparing the effectiveness and safety of these two drugs in the Mexican population. The aim of this study was to compare the effectiveness of TPV versus DRV as a salvage therapy in HIV-1 treatment-experienced patients. This was a comparative, prospective, cohort study. Patients with HIV and triple-class drug resistance evaluated at the Hospital de Infectología "La Raza", National Medical Center, were included. All patients had the protease and retrotranscriptase genotype; resistance mutation interpretation was done using the Stanford database. A total of 35 HIV-1 triple-class drug-resistant patients were analyzed. All of them received tenofovir and raltegravir, 22 received darunavir/ritonavir (DRV/r), and 13 received tipranavir/ritonavir (TPV/r) therapies. The median baseline RNA HIV-1 viral load and CD4+ cell count were 4.34 log (interquartile range [IQR], 4.15-4.72) and 267 cells/mm3 (IQR, 177-320) for the DRV/r group, and 4.14 log (IQR, 3.51-4.85) and 445 cells/mm3 (IQR, 252-558) for the TPV/r group. At week 24 of treatment, 91% of patients receiving DRV/r and 100% of patients receiving TPV/r had an RNA HIV-1 viral load HIV-1 patients who were highly experienced in antiretroviral therapy.

Preparation and Properties of Novel Thermoplastic Vulcanizate Based on Bio-Based Polyester/Polylactic Acid, and Its Application in 3D Printing

Directory of Open Access Journals (Sweden)

Yu Gao

2017-12-01

Full Text Available Thermoplastic vulcanizate (TPV combines the high elasticity of elastomers and excellent processability of thermoplastics. Novel bio-based TPV based on poly (lactide (PLA and poly (1,4-butanediol/2,3-butanediol/succinate/itaconic acid (PBBSI were prepared in this research. PBBSI copolyesters were synthesized by melting polycondensation, and the molecular weights, chemical structures and compositions of the copolyesters were characterized by GPC, NMR and FTIR. Bio-based 2,3-butanediol was successfully incorporated to depress the crystallization behavior of the PBBSI copolyester. With an increase of 2,3-butanediol content, the PBBSI copolyester transformed from a rigid plastic to a soft elastomer. Furthermore, the obtained TPV has good elasticity and rheological properties, which means it can be applied as a 3D-printing material.

Changes in Speckle Tracking Echocardiography Measures of Ventricular Function after Percutaneous Implantation of the Edwards SAPIEN Transcatheter Heart Valve in the Pulmonary Position

Science.gov (United States)

Chowdhury, Shahryar M.; Hijazi, Ziyad M.; Rhodes, John F.; Kar, Saibal; Makkar, Raj; Mullen, Michael; Cao, Qi-Ling; Mandinov, Lazar; Buckley, Jason; Pietris, Nicholas P.; Shirali, Girish S.

2015-01-01

Background Patients with free pulmonary regurgitation or mixed pulmonary stenosis and regurgitation and severely dilated right ventricles (RV) show little improvement in ventricular function after pulmonary valve replacement when assessed by traditional echocardiographic markers. We evaluated changes in right and left ventricular (LV) function using speckle tracking echocardiography in patients after SAPIEN transcatheter pulmonary valve (TPV) placement. Methods Echocardiograms were evaluated at baseline, discharge, 1 and 6 months after TPV placement in 24 patients from 4 centers. Speckle tracking measures of function included peak longitudinal strain, strain rate, and early diastolic strain rate. RV fractional area change, tricuspid annular plane systolic excursion, and left ventricular LV ejection fraction were assessed. Routine Doppler and tissue Doppler velocities were measured. Results At baseline, all patients demonstrated moderate to severe pulmonary regurgitation; this improved following TPV placement. No significant changes were detected in conventional measures of RV or LV function at 6 months. RV longitudinal strain (−16.9% vs. −19.6%, P echocardiography may be more sensitive than traditional measures in detecting changes in systolic function after TPV implantation. (Echocardiography 2015;32:461–469) PMID:25047063

Measuring the health impact of human rights violations related to Australian asylum policies and practices: a mixed methods study

Directory of Open Access Journals (Sweden)

Mulholland Kim

2009-02-01

Full Text Available Abstract Background Human rights violations have adverse consequences for health. However, to date, there remains little empirical evidence documenting this association, beyond the obvious physical and psychological effects of torture. The primary aim of this study was to investigate whether Australian asylum policies and practices, which arguably violate human rights, are associated with adverse health outcomes. Methods We designed a mixed methods study to address the study aim. A cross-sectional survey was conducted with 71 Iraqi Temporary Protection Visa (TPV refugees and 60 Iraqi Permanent Humanitarian Visa (PHV refugees, residing in Melbourne, Australia. Prior to a recent policy amendment, TPV refugees were only given temporary residency status and had restricted access to a range of government funded benefits and services that permanent refugees are automatically entitled to. The quantitative results were triangulated with semi-structured interviews with TPV refugees and service providers. The main outcome measures were self-reported physical and psychological health. Standardised self-report instruments, validated in an Arabic population, were used to measure health and wellbeing outcomes. Results Forty-six percent of TPV refugees compared with 25% of PHV refugees reported symptoms consistent with a diagnosis of clinical depression (p = 0.003. After controlling for the effects of age, gender and marital status, TPV status made a statistically significant contribution to psychological distress (B = 0.5, 95% CI 0.3 to 0.71, p ≤ 0.001 amongst Iraqi refugees. Qualitative data revealed that TPV refugees generally felt socially isolated and lacking in control over their life circumstances, because of their experiences in detention and on a temporary visa. This sense of powerlessness and, for some, an implicit awareness they were being denied basic human rights, culminated in a strong sense of injustice. Conclusion Government asylum policies

Space Photovoltaic Research and Technology 1995

Science.gov (United States)

Landis, Geoffrey (Compiler)

1995-01-01

The Fourteenth Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from October 24-26, 1995. The abstracts presented in this volume report substantial progress in a variety of areas in space photovoltaics. Technical and review papers were presented in many areas, including high efficiency GaAs and InP solar cells, GaAs/Ge cells as commercial items, high efficiency multiple bandgap cells, solar cell and array technology, heteroepitaxial cells, thermophotovoltaic energy conversion, and space radiation effects. Space flight data on a variety of cells were also presented.

Measuring the health impact of human rights violations related to Australian asylum policies and practices: a mixed methods study.

Science.gov (United States)

Johnston, Vanessa; Allotey, Pascale; Mulholland, Kim; Markovic, Milica

2009-02-03

Human rights violations have adverse consequences for health. However, to date, there remains little empirical evidence documenting this association, beyond the obvious physical and psychological effects of torture. The primary aim of this study was to investigate whether Australian asylum policies and practices, which arguably violate human rights, are associated with adverse health outcomes. We designed a mixed methods study to address the study aim. A cross-sectional survey was conducted with 71 Iraqi Temporary Protection Visa (TPV) refugees and 60 Iraqi Permanent Humanitarian Visa (PHV) refugees, residing in Melbourne, Australia. Prior to a recent policy amendment, TPV refugees were only given temporary residency status and had restricted access to a range of government funded benefits and services that permanent refugees are automatically entitled to. The quantitative results were triangulated with semi-structured interviews with TPV refugees and service providers. The main outcome measures were self-reported physical and psychological health. Standardised self-report instruments, validated in an Arabic population, were used to measure health and wellbeing outcomes. Forty-six percent of TPV refugees compared with 25% of PHV refugees reported symptoms consistent with a diagnosis of clinical depression (p = 0.003). After controlling for the effects of age, gender and marital status, TPV status made a statistically significant contribution to psychological distress (B = 0.5, 95% CI 0.3 to 0.71, p basic human rights, culminated in a strong sense of injustice. Government asylum policies and practices violating human rights norms are associated with demonstrable psychological health impacts. This link between policy, rights violations and health outcomes offers a framework for addressing the impact of socio-political structures on health.

Capillary zone electrophoresis method to assay tipranavir capsules and identification of oxidation product and organic impurity by quadrupole-time of flight mass spectrometry.

Science.gov (United States)

Lago, Matheus Wagner; Friedrich, Mariane Lago; Iop, Gabrielle Dineck; de Souza, Thiago Belarmino; de Azevedo Mello, Paola; Adams, Andréa Inês Horn

2018-05-01

Tipranavir (TPV) is one of the most recently developed protease inhibitors (PI) and it is specially recommended for treatment-experienced patients who are resistant to other PI drugs. In this work, a simple and friendly environmental CZE stability-indicating method to assay TPV capsules was developed and two TPV organic impurities were identified by high resolution mass spectrometry (HRMS). The optimized analytical conditions were: background electrolyte composed of sodium borate 50mM, pH 9.0 and 5% of methanol; voltage + 28kV; hydrodynamic injection of 5s (100mbar), detection wavelength 240nm, at 25°C. The separation was achieved in a fused silica capillary with 50µm × 40cm (inner diameter × effective length), using furosemide as internal standard. All the validation parameters were met and the method was specific, even in the presence of degradation products and impurities. Oxidation was indicated as the main degradation pathway among those evaluated in this study (acidic, alkaline, thermal, photolytic and oxidative) and it showed a second order degradation kinetic, under the conditions used in this study. The main oxidation product and an organic impurity detected in the standard were characterized by Q-TOF, and both of them correspond to oxidation products of TPV. Copyright © 2018 Elsevier B.V. All rights reserved.

Stent fracture, valve dysfunction, and right ventricular outflow tract reintervention after transcatheter pulmonary valve implantation: patient-related and procedural risk factors in the US Melody Valve Trial.

Science.gov (United States)

McElhinney, Doff B; Cheatham, John P; Jones, Thomas K; Lock, James E; Vincent, Julie A; Zahn, Evan M; Hellenbrand, William E

2011-12-01

Among patients undergoing transcatheter pulmonary valve (TPV) replacement with the Melody valve, risk factors for Melody stent fracture (MSF) and right ventricular outflow tract (RVOT) reintervention have not been well defined. From January 2007 to January 2010, 150 patients (median age, 19 years) underwent TPV implantation in the Melody valve Investigational Device Exemption trial. Existing conduit stents from a prior catheterization were present in 37 patients (25%, fractured in 12); 1 or more new prestents were placed at the TPV implant catheterization in 51 patients. During follow-up (median, 30 months), MSF was diagnosed in 39 patients. Freedom from a diagnosis of MSF was 77±4% at 14 months (after the 1-year evaluation window) and 60±9% at 39 months (3-year window). On multivariable analysis, implant within an existing stent, new prestent, or bioprosthetic valve (combined variable) was associated with longer freedom from MSF (Pbioprosthetic valve was associated with lower risk of MSF and reintervention.

Kinematic characteristics of tenodesis grasp in C6 quadriplegia.

Science.gov (United States)

Mateo, S; Revol, P; Fourtassi, M; Rossetti, Y; Collet, C; Rode, G

2013-02-01

Descriptive control case study. To analyze the kinematics of tenodesis grasp in participants with C6 quadriplegia and healthy control participants in a pointing task and two daily life tasks involving a whole hand grip (apple) or a lateral grip (floppy disk). France. Four complete participants with C6 quadriplegia were age matched with four healthy control participants. All participants were right-handed. The measured kinematic parameters were the movement time (MT), the peak velocity (PV), the time of PV (TPV) and the wrist angle in the sagittal plane at movement onset, at the TPV and at the movement end point. The participants with C6 quadriplegia had significantly longer MTs in both prehension tasks. No significant differences in TPV were found between the two groups. Unlike control participants, for both prehension tasks the wrist of participants with C6 quadriplegia was in a neutral position at movement onset, in flexion at the TPV, and in extension at the movement end point. Two main kinematic parameters characterize tenodesis grasp movements in C6 quadriplegics: wrist flexion during reaching and wrist extension during the grasping phase, and increased MT reflecting the time required to adjust the wrist's position to achieve the tenodesis grasp. These characteristics were observed for two different grips (whole hand and lateral grip). These results suggest sequential planning of reaching and tenodesis grasp, and should be taken into account for prehension rehabilitation in patients with quadriplegia.

Spin Caloritronic Transport of 1,3,5-Triphenylverdazyl Radical

International Nuclear Information System (INIS)

Wu Qiu-Hua; Zhao Peng; Liu De-Sheng

2016-01-01

We investigate theoretically the spin caloritronic transport properties of a stable 1,3,5-triphenylverdazyl (TPV) radical sandwiched between Au electrodes through different connection fashions. Obvious spin Seebeck effect can be observed in the para-connection fashion. Furthermore, a pure spin current and a completely spin-polarized current can be realized by tuning the gate voltage. Furthermore, a 100% spin polarization without the need of gate voltage can be obtained in the meta-connection fashion. These results demonstrate that TPV radical is a promising material for spin caloritronic and spintronic applications. (paper)

Non-invasive clinical parameters for the prediction of urodynamic bladder outlet obstruction: analysis using causal Bayesian networks.

Directory of Open Access Journals (Sweden)

Myong Kim

Full Text Available To identify non-invasive clinical parameters to predict urodynamic bladder outlet obstruction (BOO in patients with benign prostatic hyperplasia (BPH using causal Bayesian networks (CBN.From October 2004 to August 2013, 1,381 eligible BPH patients with complete data were selected for analysis. The following clinical variables were considered: age, total prostate volume (TPV, transition zone volume (TZV, prostate specific antigen (PSA, maximum flow rate (Qmax, and post-void residual volume (PVR on uroflowmetry, and International Prostate Symptom Score (IPSS. Among these variables, the independent predictors of BOO were selected using the CBN model. The predictive performance of the CBN model using the selected variables was verified through a logistic regression (LR model with the same dataset.Mean age, TPV, and IPSS were 6.2 (±7.3, SD years, 48.5 (±25.9 ml, and 17.9 (±7.9, respectively. The mean BOO index was 35.1 (±25.2 and 477 patients (34.5% had urodynamic BOO (BOO index ≥40. By using the CBN model, we identified TPV, Qmax, and PVR as independent predictors of BOO. With these three variables, the BOO prediction accuracy was 73.5%. The LR model showed a similar accuracy (77.0%. However, the area under the receiver operating characteristic curve of the CBN model was statistically smaller than that of the LR model (0.772 vs. 0.798, p = 0.020.Our study demonstrated that TPV, Qmax, and PVR are independent predictors of urodynamic BOO.

Periodic Arrays of Film-Coupled Cubic Nanoantennas as Tunable Plasmonic Metasurfaces

Directory of Open Access Journals (Sweden)

Vassilios Yannopapas

2015-03-01

Full Text Available We show theoretically that a two-dimensional periodic array of metallic nanocubes in close proximity to a metallic film acts as a metasurface with tunable absorbance. The presence of a metallic film underneath the array of plasmonic nanocubes leads to an impedance matched plasmonic metasurface enhancing up to 4 times the absorbance of incident radiation, in the spectral region below 500 nm. The absorbance spectrum is weakly dependent on the angle of incidence and state of polarization of incident light a functionality which can find application in thermo-photovoltaics. Our calculations are based on a hybrid layer-multiple-scattering (hLMS method based on a discrete-dipole approximation (DDA/T-matrix point matching method.

Visible and near-infrared radiative properties of vertically aligned multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Wang, X J; Zhang, Z M; Flicker, J D; Ready, W J; Lee, B J

2009-01-01

This work investigates the reflection and scattering from vertically aligned carbon nanotubes, fabricated on silicon substrate using thermally enhanced chemical vapor deposition with both tip-growth and base-growth mechanisms. The directional-hemispherical reflectance in the visible and near-infrared wavelengths was measured with an integrating sphere. The polarization-dependent bidirectional reflectance distribution function was characterized with a laser scatterometer at the wavelength of 635 nm. The effective medium theory was used to elucidate the mechanism of high absorptance (greater than 0.97 in the spectral region from 400 to 1800 nm) of the multi-walled carbon nanotube samples. It is observed that scattering by impurities on the top of the nanotubes, by the nanotube tips, and by defects and misalignment can significantly increase the reflectance and introduce retroreflection. This study may facilitate application of carbon nanotubes in pyroelectric detectors as well as thermophotovoltaic emitters and absorbers.

Metal photonics and plasmonics for energy generation

Science.gov (United States)

Nagpal, Prashant

Energy generation from renewable sources and conservation of energy are important goals for reducing our carbon footprint on the environment. Important sources of renewable energy like sun and geothermal energy are difficult to harness because of their energetically broad radiation. Most of our current energy requirements are met through consumption of fossil fuels, and more than 60% of this energy is released to the environment as "waste heat". Thus, converting heat from sun, or inefficient furnaces and automobiles can provide an important source of energy generation. In the present work, I describe design, fabrication, and characterization two and three dimensional patterned metals. These nanofabricated structures can be used as selective emitters to tailor the glow of hot objects. The tailored radiation can then be converted efficiently into electricity using an infrared photocell. This thermophotovoltaic conversion can be very efficient, and useful for converting heat-to-electricity from a wide variety of sources.

Thermoplastic Elastomers From Chemically or Irradiation Activated Polyolefin Wastes and Ground Tyre Rubber

International Nuclear Information System (INIS)

Tolstov, A.M.; Grigoryeva, A.L.; Bardash, O.P.

2005-01-01

Thermoplastic elastomers (TPE) are known as materials with unique combination of elastomeric properties and thermo plasticity. Among the TPE of different type the polymer blends of thermoplastics and rubbers are the most commonly used. Recently a very effective technology of dynamic vulcanization of rubber component inside thermoplastic matrix has been developed. As a result of rubber vulcanization and dispersion inside thermoplastic the new type of TPE so-called thermoplastic dynamic vulcanizations (TPV) are obtained. In our work we have applied the technology of dynamic vulcanization for recycled components (PP, HDPE, GTR). It has appeared that such components are not mixed well and the resulting TPV have poor mechanical properties. To solve a problem of poor compatibility of the components used we carried out a pre-modification (functionalization) of the component surfaces by gamma-irradiation or by chemically or gamma-irradiation induced grafting of reactive monomers. Both the polyolefin (HDPE) and GTR were functionalized before mixing. The monomers were selected by such a way that being grafted to be able to react to each other in interface during the components blending. For example, we used maleic anhydride and acrylamide. The effect of better compatibility has appeared in higher tensile characteristics of TPV synthesized

Investigation on γ-irradiated PP/ethylene acrylic elastomer TPVs by rheological and thermal approaches

Science.gov (United States)

Dutta, Anindya; Ghosh, Anup K.

2018-03-01

Polypropylene (PP) was melt blended with varying concentration of ethylene acrylic elastomer (AEM) in a twin screw extruder and then γ-irradiated at several radiation doses to achieve a series of thermoplastic vulcanizates (TPV). The effect of AEM concentration and γ-irradiation on flow characteristics, crystallization and thermal degradation of blends were explained using melt dynamic rheology, differential scanning calorimetry and thermogravimetric analysis. Gel content values and dynamic rheological data of PP and AEM at different radiation doses confirmed the incessant scissioning of PP chains with radiation doses except for highest radiation dose, where crosslinking of PP chains took place and the incessant crosslinking of AEM chains irrespective of radiation doses. Oxidative degradation of PP was confirmed by FTIR spectroscopy, which also exhibited absence of any chemical interaction between two constituent polymers. Normalized crystallinity and melting point of compositions, obtained from DSC, decreased with the radiation doses. Furthermore, with the radiation doses clear shifts of maxima of the melting peak towards the lower temperature were observed for neat PP and blends. Thermal stability of PP and blends, as observed by TGA, reduced significantly with irradiation; whereas for AEM, no discernable change was observed. Enhanced chain scissioning of PP in presence of AEM reduced the thermal stability of blends, especially at lower irradiation. This reduction of thermal stability was established by "rule of mixture", applied to the activation energy of thermal degradation. Thus, optimization of radiation doses to prepare TPVs was established.

Ionizing radiation, radiation sources, radiation exposure, radiation effects. Pt. 2

International Nuclear Information System (INIS)

Schultz, E.

1985-01-01

Part 2 deals with radiation exposure due to artificial radiation sources. The article describes X-ray diagnosis complete with an analysis of major methods, nuclear-medical diagnosis, percutaneous radiation therapy, isotope therapy, radiation from industrial generation of nucler energy and other sources of ionizing radiation. In conclusion, the authors attempt to asses total dose, genetically significant dose and various hazards of total radiation exposure by means of a summation of all radiation impacts. (orig./WU) [de

Sarcopenia Adversely Impacts Postoperative Complications Following Resection or Transplantation in Patients with Primary Liver Tumors

Science.gov (United States)

Valero, Vicente; Amini, Neda; Spolverato, Gaya; Weiss, Matthew J.; Hirose, Kenzo; Dagher, Nabil N.; Wolfgang, Christopher L.; Cameron, Andrew A.; Philosophe, Benjamin; Kamel, Ihab R.

2015-01-01

Background Sarcopenia is a surrogate marker of patient frailty that estimates the physiologic reserve of an individual patient. We sought to investigate the impact of sarcopenia on short- and long-term outcomes in patients having undergone surgical intervention for primary hepatic malignancies. Methods Ninety-six patients who underwent hepatic resection or liver transplantation for HCC or ICC at the John Hopkins Hospital between 2000 and 2013 met inclusion criteria. Sarcopenia was assessed by the measurement of total psoas major volume (TPV) and total psoas area (TPA). The impact of sarcopenia on perioperative complications and survival was assessed. Results Mean age was 61.9 years and most patients were men (61.4 %). Mean adjusted TPV was lower in women (23.3 cm3/m) versus men (34.9 cm3/m) (Psarcopenia. The incidence of a postoperative complication was 40.4 % among patients with sarcopenia versus 18.4 % among patients who did not have sarcopenia (P=0.01). Of note, all Clavien grade ≥3 complications (n=11, 23.4 %) occurred in the sarcopenic group. On multivariable analysis, the presence of sarcopenia was an independent predictive factor of postoperative complications (OR=3.06). Sarcopenia was not associated with long-term survival (HR=1.23; P=0.51). Conclusions Sarcopenia, as assessed by TPV, was an independent factor predictive of postoperative complications following surgical intervention for primary hepatic malignancies. PMID:25389056

Therapeutic potential of and treatment with boceprevir/telaprevir-based triple-therapy in HIV/chronic hepatitis C co-infected patients in a real-world setting.

Science.gov (United States)

Mandorfer, Mattias; Payer, Berit A; Niederecker, Alexander; Lang, Gerold; Aichelburg, Maximilian C; Strassl, Robert; Boesecke, Christoph; Rieger, Armin; Trauner, Michael; Peck-Radosavljevic, Markus; Reiberger, Thomas

2014-05-01

The aim of this study was to assess the therapeutic potential of telaprevir (TPV)/boceprevir (BOC)-based triple-therapy in a complete cohort of HIV/chronic hepatitis C co-infected patients (HIV/HCV). Moreover, a case series of four HIV/HCV genotype (HCV-GT)1 patients with rapid virologic response (RVR), who received only 28 weeks of BOC-based triple-therapy (BOCW28), was reported. 290/440 HIV-positive patients with positive HCV serology had at least one visit during the past 2 years, 142/290 had target detectable HCV-RNA with 64% (82/142) carrying HCV-GT1. While 18 HIV/HCV-GT1 displayed contraindications, 45% (64/142) of HIV/HCV were eligible for triple-therapy. Insufficiently controlled HIV-infection despite combined antiretroviral therapy (cART) (HIV-RNA treatment uptake rates (39% (25/64)) during the first 2 years of triple-therapy availability suggest that its benefit in HIV/HCV co-infected patients might fall short of expectations. Modification of cART or TPV dose adjustment would have been necessary in 61% and 84% of HIV/HCV-GT1 on cART eligible for triple-therapy using TPV and BOC, respectively, suggesting that drug-drug interactions with cART complicate management in the majority of patients. All four BOCW28 patients achieved a sustained virologic response. Prospective studies are necessary to validate our observations on the shortening of treatment duration in HIV/HCV-GT1 with RVR.

Vpliv kaizna na proizvodno linijo podjetja TPV d.d.

OpenAIRE

Gramc, Nina

2013-01-01

Domnevamo lahko, da je filozofija Kaizen eden od vzrokov in hkrati motivator za dolgoročno konkurenčno prednost podjetja. Koncept je definiran kot obsežen organizacijski proces, osredotočen na kontinuiteto izboljšav in načrtno vključevanje vsakega posameznika v organizaciji v iskanje izboljšav. Zato je lahko prav Kaizen eden ključnih pokazateljev, ki loči med uspehom enih in odpovedjo oziroma propadom drugih podjetij. Razmere, ki jih dandanes srečujemo v podjetju (razne napake, strojelomi...

Atoms, radiation, and radiation protection

International Nuclear Information System (INIS)

Turner, J.E.

1986-01-01

This book describes basic atomic and nuclear structure, the physical processes that result in the emission of ionizing radiations, and external and internal radiation protection criteria, standards, and practices from the standpoint of their underlying physical and biological basis. The sources and properties of ionizing radiation-charged particles, photons, and neutrons-and their interactions with matter are discussed in detail. The underlying physical principles of radiation detection and systems for radiation dosimetry are presented. Topics considered include atomic physics and radiation; atomic structure and radiation; the nucleus and nuclear radiation; interaction of heavy charged particles with matter; interaction of beta particles with matter; phenomena associated with charged-particle tracks; interaction of photons with matter; neutrons, fission and criticality; methods of radiation detection; radiation dosimetry; chemical and biological effects of radiation; radiation protection criteria and standards; external radiation protection; and internal dosimetry and radiation protection

NASA Tech Briefs, April 2009

Science.gov (United States)

2009-01-01

Topics covered include: Direct-Solve Image-Based Wavefront Sensing; Use of UV Sources for Detection and Identification of Explosives; Using Fluorescent Viruses for Detecting Bacteria in Water; Gradiometer Using Middle Loops as Sensing Elements in a Low-Field SQUID MRI System; Volcano Monitor: Autonomous Triggering of In-Situ Sensors; Wireless Fluid-Level Sensors for Harsh Environments; Interference-Detection Module in a Digital Radar Receiver; Modal Vibration Analysis of Large Castings; Structural/Radiation-Shielding Epoxies; Integrated Multilayer Insulation; Apparatus for Screening Multiple Oxygen-Reduction Catalysts; Determining Aliasing in Isolated Signal Conditioning Modules; Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems; Spectrum Analyzers Incorporating Tunable WGM Resonators; Quantum-Well Thermophotovoltaic Cells; Bounded-Angle Iterative Decoding of LDPC Codes; Conversion from Tree to Graph Representation of Requirements; Parallel Hybrid Vehicle Optimal Storage System; and Anaerobic Digestion in a Flooded Densified Leachbed.

Radiation practices and radiation measurements

International Nuclear Information System (INIS)

2008-03-01

The guide presents the principal requirements on accuracy of radiation measurements and on the approval, calibration and operating condition inspections of radiation meters, together with requirements for dosimetric services measuring the individual radiation doses of workers engaged in radiation work (approved dosimetric services). The Guide also sets out the definitions of quantities and units used in radiation measurements. The radiation protection quantities used for assessing the harmful effects of radiation and for expressing the maximum values for radiation exposure (equivalent dose and effective dose) are set out in Guide ST 7.2. This Guide concerns measurements of ionizing radiation involved in radiation practices, the results of which are used for determining the radiation exposure of workers engaged in radiation work and members of the public, and of patients subject to the use of radiation in health services, or upon the basis of which compliance with safety requirements of appliances currently in use and of their premises of use or of the workplaces of workers is ensured. The Guide also concerns measurements of the radon concentration of inhaled air in both workplaces and dwellings. The Guide does not apply to determining the radiation exposure of aircrews, determination of exposure caused by internal radiation, or measurements made to protect the public in the event of, or in preparation for abnormal radiation conditions

Enhanced energy transfer by near-field coupling of a nanostructured metamaterial with a graphene-covered plate

International Nuclear Information System (INIS)

Chang, Jui-Yung; Yang, Yue; Wang, Liping

2016-01-01

Coupled surface plasmon/phonon polaritons and hyperbolic modes are known to enhance radiative transfer across nanometer vacuum gaps but usually require identical materials. It becomes crucial to achieve strong near-field energy transfer between dissimilar materials for applications like near-field thermophotovoltaic and thermal rectification. In this work, we theoretically demonstrate enhanced near-field radiative transfer between a nanostructured metamaterial emitter and a graphene-covered planar receiver. Strong near-field coupling with two orders of magnitude enhancement in the spectral heat flux is achieved at the gap distance of 20 nm. By carefully selecting the graphene chemical potential and doping levels of silicon nanohole emitter and silicon plate receiver, the total near-field radiative heat flux can reach about 500 times higher than the far-field blackbody limit between 400 K and 300 K. The physical mechanism is elucidated by the near-field surface plasmon coupling with fluctuational electrodynamics and dispersion relations. The effects of graphene chemical potential, emitter and receiver doping levels, and vacuum gap distance on the near-field coupling and radiative energy transfer are analyzed in detail. - Highlights: • Near-field radiative transfer between a metamaterial and a graphene-covered plate is studied. • Effective medium theory with uniaxial optics is employed to model nanohole metamaterials. • Enhancement by 2 orders is found between dissimilar materials with graphene coating. • Extraordinary coupling of the nanostructured emitter with graphene is elucidated. • Effects of doping level of silicon and graphene chemical potential are investigated.

Thought and Practice - Vol 6, No 1 (2014)

African Journals Online (AJOL)

A Critique of Foucault's Conception and Predictions of the Author-Function · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. J Situma, 9-24. http://dx.doi.org/10.4314/tp.v6i1.3 ...

Inter-Scan Reproducibility of Carotid Plaque Volume Measurements by 3-D Ultrasound

DEFF Research Database (Denmark)

Sandholt, Benjamin V; Collet-Billon, Antoine; Entrekin, Robert

2018-01-01

(PPV) measure centered on MPT. Total plaque volume (TPV), PPV from a 10-mm segment and MPT were measured using dedicated semi-automated software on 38 plaques from 26 patients. Inter-scan reproducibility was assessed using the t-test, Bland-Altman plots and Pearson's correlation coefficient....... There was a mean difference of 0.01 mm in MPT (limits of agreement: -0.45 to 0.42 mm, Pearson's correlation coefficient: 0.96). Both volume measurements exhibited high reproducibility, with PPV being superior (limits of agreement: -35.3 mm3to 33.5 mm3, Pearson's correlation coefficient: 0.96) to TPV (limits...... of agreement: -88.2 to 61.5 mm3, Pearson's correlation coefficient: 0.91). The good reproducibility revealed by the present results encourages future studies on establishing plaque quantification as part of cardiovascular risk assessment and for follow-up of disease progression over time....

Radiation and radiation protection; Strahlung und Strahlenschutz

Energy Technology Data Exchange (ETDEWEB)

Bartholomaeus, Melanie (comp.)

2017-04-15

The publication of the Bundesamt fuer Strahlenschutz covers the following issues: (i) Human beings in natural and artificial radiation fields; (ii) ionizing radiation: radioactivity and radiation, radiation exposure and doses; measurement of ionizing radiation, natural radiation sources, artificial radiation sources, ionizing radiation effects on human beings, applied radiation protection, radiation exposure of the German population, radiation doses in comparison; (iii) non-ionizing radiation; low-frequency electric and magnetic fields, high-frequency electromagnetic fields, optical radiation; (iiii) glossary, (iv) units and conversion.

76 FR 6826 - Certain Display Devices Including Digital Televisions and Monitors; Notice of Commission...

Science.gov (United States)

2011-02-08

... Commission instituted this investigation on April 21, 2010, based on a complaint filed by Sony Corporation of Japan (``Sony''). 75 FR 20860-1. The complaint, as amended and supplemented, alleges violations of... Corporation and Innolux Corporation (collectively ``CMI''); TPV Technology Limited; Top Victory Electronics...

Infrared Radiation and Blackbody Radiation

OpenAIRE

2005-01-01

tut present graph Tutorial Presentation Graph Interactive Media Element This interactive tutorial covers the following: How infrared radiation was discovered., The regions of infrared radiation and their relations to temperature., The nature of blackbody radiation and Planck's radiation law., The relationship between temperature and the power emitted by radiation.The interactions in this tutorial include clicking to reveal new information, and questions that help students...

Development of a cloud-based system for remote monitoring of a PVT panel

Science.gov (United States)

Saraiva, Luis; Alcaso, Adérito; Vieira, Paulo; Ramos, Carlos Figueiredo; Cardoso, Antonio Marques

2016-10-01

The paper presents a monitoring system developed for an energy conversion system based on the sun and known as thermophotovoltaic panel (PVT). The project was implemented using two embedded microcontrollers platforms (arduino Leonardo and arduino yún), wireless transmission systems (WI-FI and XBEE) and net computing ,commonly known as cloud (Google cloud). The main objective of the project is to provide remote access and real-time data monitoring (like: electrical current, electrical voltage, input fluid temperature, output fluid temperature, backward fluid temperature, up PV glass temperature, down PV glass temperature, ambient temperature, solar radiation, wind speed, wind direction and fluid mass flow). This project demonstrates the feasibility of using inexpensive microcontroller's platforms and free internet service in theWeb, to support the remote study of renewable energy systems, eliminating the acquisition of dedicated systems typically more expensive and limited in the kind of processing proposed.

Endodoncia regenerativa: utilización de fibrina rica en plaquetas autóloga en dientes permanentes vitales con patología pulpar. Revisión narrativa de la literatura*

Directory of Open Access Journals (Sweden)

Tatiana Ramírez Giraldo

2014-01-01

Full Text Available Actualmente una de las mayores controversias en el tratamiento de dientes permanentes con diagnóstico de pulpitis está en la decisión de realizar una Terapia Pulpar Vital (TPV o un tratamiento convencional de conductos. Diferentes estudios han reportado que se pueden obtener resultados previsibles mediante la realización de una TPV. El éxito del tratamiento dependerá de una adecuada comprensión de la  biología pulpar, un estricto protocolo de tratamiento y una adecuada selección del caso. Con este fin, diferentes materiales han sido sugeridos. Recientemente se ha utilizado la Fibrina Rica en Plaquetas, biomaterial que cumple con propiedades biológicas para lograr una mayor rapidez y adecuada cicatrizacion del tejido. Es necesario desarrollar tratamientos dirigidos a preservar la vitalidad de la pulpa, evitando recurrir como primera opción al tratamiento convencional de conductos, teniendo como objetivo conservar o regenerar el complejo dentino pulpar.

Endodoncia regenerativa: utilización de fibrina rica en plaquetas autóloga en dientes permanentes vitales con patología pulpar. Revisión narrativa de la literatura*

Directory of Open Access Journals (Sweden)

Tatiana Ramírez Giraldo

2014-07-01

Full Text Available Actualmente una de las mayores controversias en el tratamiento de dientes permanentes con diagnóstico de pulpitis está en la decisión de realizar una Terapia Pulpar Vital (TPV o un tratamiento convencional de conductos. Diferentes estudios han reportado que se pueden obtener resultados previsibles mediante la realización de una TPV. El éxito del tratamiento dependerá de una adecuada comprensión de la  biología pulpar, un estricto protocolo de tratamiento y una adecuada selección del caso. Con este fin, diferentes materiales han sido sugeridos. Recientemente se ha utilizado la Fibrina Rica en Plaquetas, biomaterial que cumple con propiedades biológicas para lograr una mayor rapidez y adecuada cicatrizacion del tejido. Es necesario desarrollar tratamientos dirigidos a preservar la vitalidad de la pulpa, evitando recurrir como primera opción al tratamiento convencional de conductos, teniendo como objetivo conservar o regenerar el complejo dentino pulpar.

Radiation exposure and radiation protection

International Nuclear Information System (INIS)

Heuck, F.; Scherer, E.

1985-01-01

The present volume is devoted to the radiation hazards and the protective measures which can be taken. It describes the current state of knowledge on the changes which exposure to ionizing rays and other forms of physical energy can induce in organs and tissues, in the functional units and systems of the organism. Special attention is paid to general cellular radiation biology and radiation pathology and to general questions of the biological effects of densely ionizing particle radiation, in order to achieve a better all-round understanding of the effects of radiation on the living organism. Aside from the overviews dealing with the effects of radiation on the abdominal organs, urinary tract, lungs, cerebral and nervous tissue, bones, and skin, the discussion continues with the lymphatic system, the bone marrow as a bloodforming organ, and the various phases of reaction in the reproductive organs, including damage and subsequent regeneration. A special section deals with environmental radiation hazards, including exposure to natural radiation and the dangers of working with radioactive substances, and examines radiation catastrophes from the medical point of view. Not only reactor accidents are covered, but also nuclear explosions, with exhaustive discussion of possible damage and treatment. The state of knowledge on chemical protection against radiation is reviewed in detail. Finally, there is thorough treatment of the mechanism of the substances used for protection against radiation damage in man and of experience concerning this subject to date. In the final section of the book the problems of combined radiotherapy are discussed. The improvement in the efficacy of tumor radiotherapy by means of heavy particles is elucidated, and the significance of the efficacy of tumor therapy using electron-affinitive substances is explained. There is also discussion of the simultaneous use of radiation and pharmaceuticals in the treatment of tumors. (orig./MG) [de

Atoms, Radiation, and Radiation Protection

CERN Document Server

Turner, James E

2007-01-01

Atoms, Radiation, and Radiation Protection offers professionals and advanced students a comprehensive coverage of the major concepts that underlie the origins and transport of ionizing radiation in matter. Understanding atomic structure and the physical mechanisms of radiation interactions is the foundation on which much of the current practice of radiological health protection is based. The work covers the detection and measurement of radiation and the statistical interpretation of the data. The procedures that are used to protect man and the environment from the potential harmful effects of

Interplay between Interfacial Structures and Device Performance in Organic Solar Cells: A Case Study with the Low Work Function Metal, Calcium.

Science.gov (United States)

Ju, Huanxin; Knesting, Kristina M; Zhang, Wei; Pan, Xiao; Wang, Chia-Hsin; Yang, Yaw-Wen; Ginger, David S; Zhu, Junfa

2016-01-27

A better understanding of how interfacial structure affects charge carrier recombination would benefit the development of highly efficient organic photovoltaic (OPV) devices. In this paper, transient photovoltage (TPV) and charge extraction (CE) measurements are used in combination with synchrotron radiation photoemission spectroscopy (SRPES) to gain insight into the correlation between interfacial properties and device performance. OPV devices based on PCDTBT/PC71BM with a Ca interlayer were studied as a reference system to investigate the interfacial effects on device performance. Devices with a Ca interlayer exhibit a lower recombination than devices with only an Al cathode at a given charge carrier density (n). In addition, the interfacial band structures indicate that the strong dipole moment produced by the Ca interlayer can facilitate the extraction of electrons and drive holes away from the cathode/polymer interface, resulting in beneficial reduction in interfacial recombination losses. These results help explain the higher efficiencies of devices made with Ca interlayers compared to that without the Ca interlayer.

MRI to predict prostate growth and development in children, adolescents and young adults

Energy Technology Data Exchange (ETDEWEB)

Ren, Jing; Liu, Huijia; Wen, Didi; Huang, Xufang; Ren, Fang; Huan, Yi [Fourth Military Medical University, Department of Radiology, Xijing Hospital, Xi' an City (China); Wang, He [Fourth Military Medical University, Department of Urology, Tangdu Hospital, Xi' an City (China)

2014-08-06

The purpose of this study was to investigate the use of MRI in predicting prostate growth and development. A total of 1,500 healthy male volunteers who underwent MRI of the pelvis were included in this prospective study. Subjects were divided into five groups according to age (group A, 2-5 years; group B, 6-10 years; group C, 11-15 years; group D, 16-20 years; group E, 21-25 years). Total prostate volume (TPV) as well as prostate central zone (CZ) and peripheral zone (PZ) were measured and evaluated on MRI. Data of the different groups were compared using variance analysis, Scheffe's method, Kruskal-Wallis H-test, and Pearson's correlation. Statistical significance was inferred at P < 0.05. In groups A and B, the prostates were barely visible. In group C, although TPV was measured, it was hard to distinguish CZ and PZ. In group D, 136 CZ and PZ were clearly visible. In group E, 377 CZ and PZ were clearly visible on T2-weighted imaging (T2WI). The median TPVs of groups A, B, C, D, and E were 0.00 cm{sup 3}, 0.05 cm{sup 3}, 2.83 cm{sup 3}, 8.32 cm{sup 3,} and 11.56 cm{sup 3}, respectively, and the median prostate development scores were 0.08, 0.69, 1.56, 2.38, and 2.74, respectively. Both TPVs and zonal anatomy scores varied significantly among the five groups (P = 0.000). TPV and zonal anatomy score increased with increasing age. MRI provides a reliable quantitative reference for prostate growth and development. (orig.)

Radiation dosimetry and radiation biophysics

International Nuclear Information System (INIS)

Anon.

1981-01-01

Radiation dosimetry and radiation biophysics are two closely integrated programs whose joint purpose is to explore the connections between the primary physical events produced by radiation and their biological consequences in cellular systems. The radiation dosimetry program includes the theoretical description of primary events and their connection with the observable biological effects. This program also is concerned with the design and measurement of physical parameters used in theory or to support biological experiments. The radiation biophysics program tests and uses the theoretical developments for experimental design, and provides information for further theoretical development through experiments on cellular systems

Radiation dosimetry and radiation biophysics

International Nuclear Information System (INIS)

Anon.

1979-01-01

Radiation dosimetry and radiation biophysics are two closely integrated programs whose joint purpose is to explore the connections between the primary physical events produced by radiation and their biological consequences in cellular systems. The radiation dosimetry program includes the theoretical description of primary events and their connection with the observable biological effects. This program also is concerned with design and measurement of those physical parameters used in the theory or to support biological experiments. The radiation biophysics program tests and makes use of the theoretical developments for experimental design. Also, this program provides information for further theoretical development through experiments on cellular systems

Application of radiation-induced apoptosis in radiation oncology and radiation protection

International Nuclear Information System (INIS)

Crompton, N.E.A.; Emery, G.C.; Ozsahin, M.; Menz, R.; Knesplova, L.; Larsson, B.

1997-01-01

A rapid assay of the ability of lymphocytes to respond to radiation-induced damage is presented. Age and genetic dependence of radiation response have been quantified. The assay is sensitive to low doses of radiation. Its ability to assess the cytotoxic response of blood capillaries to radiation has been evaluated. (author)

Foundations of radiation physics and radiation protection. 5. ed.

International Nuclear Information System (INIS)

Krieger, Hanno

2017-01-01

The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

Radiation

International Nuclear Information System (INIS)

2013-01-01

The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

Radiation chemistry

International Nuclear Information System (INIS)

Rodgers, F.; Rodgers, M.A.

1987-01-01

The contents of this book include: Interaction of ionizing radiation with matter; Primary products in radiation chemistry; Theoretical aspects of radiation chemistry; Theories of the solvated electron; The radiation chemistry of gases; Radiation chemistry of colloidal aggregates; Radiation chemistry of the alkali halides; Radiation chemistry of polymers; Radiation chemistry of biopolymers; Radiation processing and sterilization; and Compound index

Environmental radiation and exposure to radiation

International Nuclear Information System (INIS)

1981-02-01

Compared to 1977 the exposure to radiation of the population of the Federal Republic of Germany from both natural and artificial radiation sources has not greatly charged. The amin part of exposure to natural radiation is caused by environmental radiation and by the absorption of naturally radioactive substances into the body. Artificial exposure to radiation of the population is essentially caused by the use of ionizing rays and radioactive substances in medicine. When radioactive materials are released from nuclear facilities the exposure to radiation of the population is only very slightly increased. The real exposure to radiation of individual people can even in the worst affected places, have been at most fractions of a millirem. The exposure to radiation in the worst afected places in the area of a hard-coal power station is higher than that coming from a nuclear power station of the same capacity. The summation of all contributions to the exposure of radiation by nuclear facilities to the population led in 1978 in the Federal Republic of Germany to a genetically significant dose of clearly less than 1 millerem per year. The medium-ranged exposure to radiation by external radiation effects through professional work was in 1978 at 80 millirems. No difference to 1977. The contribution of radionuclide from the fallout coming from nuclear-weapon tests and which has been deposited in the soil, to the whole-body dose for 1978 applies the same as the genetically significant dose of the population with less than 1 millirem. (orig./HP) [de

Radiation measurement

International Nuclear Information System (INIS)

Go, Sung Jin; Kim, Seung Guk; No, Gyeong Seok; Park, Myeong Hwan; Ann, Bong Seon

1998-03-01

This book explains technical terms about radiation measurement, which are radiation, radiation quantity and unit such as prefix of international unit, unit for defence purposes of radiation, coefficient of radiation and interaction, kinds and principles of radiation detector, ionization chamber, G-M counter, G-M tube, proportional counter, scintillation detector, semiconductor radiation detector, thermoluminescence dosimeter, PLD, others detector, radiation monitor, neutron detector, calibration of radiation detector, statistics of counting value, activation analysis and electronics circuit of radiation detector.

Radiation protection medical care of radiation workers

International Nuclear Information System (INIS)

Walt, H.

1988-01-01

Radiation protection medical care for radiation workers is part of the extensive programme protecting people against dangers emanating from the peaceful application of ionizing radiation. Thus it is a special field of occupational health care and emergency medicine in case of radiation accidents. It has proved helpful in preventing radiation damage as well as in early detection, treatment, after-care, and expert assessment. The medical checks include pre-employment and follow-up examinations, continued long-range medical care as well as specific monitoring of individuals and defined groups of workers. Three levels of action are involved: works medical officers specialized in radiation protection, the Institute of Medicine at the National Board for Atomic Safety and Radiation Protection, and a network of clinical departments specialized in handling cases of acute radiation damage. An account is given of categories, types, and methods of examinations for radiation workers and operators. (author)

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

Science.gov (United States)

Farhat, Mohamed; Cheng, Tsung-Chieh; Le, Khai. Q.; Cheng, Mark Ming-Cheng; Bağcı, Hakan; Chen, Pai-Yen

2016-01-01

We present here a broadband, wide-angle, and polarization-independent nearly perfect absorber consisting of mirror-backed nanoporous alumina. By electrochemically anodizing the disordered multicomponent aluminum and properly tailoring the thickness and air-filling fraction of nanoporous alumina, according to the Maxwell-Garnet mixture theory, a large-area dark alumina can be made with excellent photothermal properties and absorption larger than 93% over a wide wavelength range spanning from near-infrared to ultraviolet light, i.e. 250 nm-2500 nm. The measured absorption is orders of magnitude greater than other reported anodized porous alumina, typically semi-transparent at similar wavelengths. This simple yet effective approach, however, does not require any lithography, nano-mixture deposition, pre- and post-treatment. Here, we also envisage and theoretically investigate the practical use of proposed absorbers and/or photothermal converters in integrated thermoelectronic and/or thermophotovoltaic energy conversion devices, which make efficient use of the entire spectrum of ambient visible to near-infrared radiation.

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

KAUST Repository

Farhat, Mohamed

2016-01-28

We present here a broadband, wide-angle, and polarization-independent nearly perfect absorber consisting of mirror-backed nanoporous alumina. By electrochemically anodizing the disordered multicomponent aluminum and properly tailoring the thickness and air-filling fraction of nanoporous alumina, according to the Maxwell-Garnet mixture theory, a large-area dark alumina can be made with excellent photothermal properties and absorption larger than 93% over a wide wavelength range spanning from near-infrared to ultraviolet light, i.e. 250 nm–2500 nm. The measured absorption is orders of magnitude greater than other reported anodized porous alumina, typically semi-transparent at similar wavelengths. This simple yet effective approach, however, does not require any lithography, nano-mixture deposition, pre- and post-treatment. Here, we also envisage and theoretically investigate the practical use of proposed absorbers and/or photothermal converters in integrated thermoelectronic and/or thermophotovoltaic energy conversion devices, which make efficient use of the entire spectrum of ambient visible to near-infrared radiation.

Radiation measurement practice for understanding statistical fluctuation of radiation count using natural radiation sources

International Nuclear Information System (INIS)

Kawano, Takao

2014-01-01

It is known that radiation is detected at random and the radiation counts fluctuate statistically. In the present study, a radiation measurement experiment was performed to understand the randomness and statistical fluctuation of radiation counts. In the measurement, three natural radiation sources were used. The sources were fabricated from potassium chloride chemicals, chemical fertilizers and kelps. These materials contain naturally occurring potassium-40 that is a radionuclide. From high schools, junior high schools and elementary schools, nine teachers participated to the radiation measurement experiment. Each participant measured the 1-min integration counts of radiation five times using GM survey meters, and 45 sets of data were obtained for the respective natural radiation sources. It was found that the frequency of occurrence of radiation counts was distributed according to a Gaussian distribution curve, although the obtained 45 data sets of radiation counts superficially looked to be fluctuating meaninglessly. (author)

Radiation carcinogenesis

International Nuclear Information System (INIS)

1978-01-01

The Cancergram deals with all aspects of radiation carcinogenesis. The term radiation here includes U-V radiation and the entire electromagnetic spectrum, electron and other charged particle beams, neutrons, and alpha and beta radiation from radioactive substances. Abstracts included concern relationships between radiation and carcinogenesis in humans, experimental induction of tumors in animals by irradiation, studies on the mechanism of radiation carcinogenesis at the cellular level, studies of RBE, dose response or dose threshold in relation to radiation carcinogenesis, and methods and policies for control of radiation exposure in the general population. In general, this Cancergram excludes abstracts on radio-therapy, radiologic diagnosis, radiation pathology, and radiation biology, where these articles have no bearing on radiation carcinogenesis

Radiation risks and radiation protection at CRNL

International Nuclear Information System (INIS)

Myers, D.K.

1986-01-01

Radiation exposure is an occupational hazard at CRNL. The predicted health effects of low levels of radiation are described and compared with other hazards of living. Data related to the health of radiation workers are also considered. Special attention is given to the expected effects of radiation on the unborn child. Measures taken to protect CRNL employees against undue occupational exposure to radiation are noted

Radiation physics, biophysics, and radiation biology

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.

1991-05-01

Research at the Radiological Research Laboratory is a blend of physics, chemistry, and biology, involving research at the basic level with the admixture of a small proportion of pragmatic or applied research in support of radiation protection and/or radiotherapy. Current research topics include: oncogenic transformation assays, mutation studies involving interactions between radiation and environmental contaminants, isolation, characterization and sequencing of a human repair gene, characterization of a dominant transforming gene found in C3H 10T1/2 cells, characterize ab initio the interaction of DNA and radiation, refine estimates of the radiation quality factor Q, a new mechanistic model of oncogenesis showing the role of long-term low dose medium LET radiation, and time dependent modeling of radiation induced chromosome damage and subsequent repair or misrepair

Radiation detection device and a radiation detection method

International Nuclear Information System (INIS)

Blum, A.

1975-01-01

A radiation detection device is described including at least one scintillator in the path of radiation emissions from a distributed radiation source; a plurality of photodetectors for viewing each scintillator; a signal processing means, a storage means, and a data processing means that are interconnected with one another and connected to said photodetectors; and display means connected to the data processing means to locate a plurality of radiation sources in said distributed radiation source and to provide an image of the distributed radiation sources. The storage means includes radiation emission response data and location data from a plurality of known locations for use by the data processing means to derive a more accurate image by comparison of radiation responses from known locations with radiation responses from unknown locations. (auth)

Radiation chemistry in development and research of radiation biology

International Nuclear Information System (INIS)

Min Rui

2010-01-01

During the establishment and development of radiation biology, radiation chemistry acts like bridge which units the spatial and temporal insight coming from radiation physics with radiation biology. The theory, model, and methodology of radiation chemistry play an important role in promoting research and development of radiation biology. Following research development of radiation biology effects towards systems radiation biology the illustration and exploration both diversity of biological responses and complex process of biological effect occurring remain to need the theory, model, and methodology come from radiation chemistry. (authors)

Foam radiators for transition radiation detectors

International Nuclear Information System (INIS)

Chernyatin, V.; Dolgoshein, B.; Gavrilenko, I.; Potekhin, M.; Romaniouk, A.; Sosnovtsev, V.

1993-01-01

A wide variety of foam radiators, potentially useful in the design of a transition radiation detector, the possible particle identification tool in collider experiments, have been tested in the beam. Various characteristics of these radiators are compared, and the conclusion is reached that certain brands of polyethylene foam are best suited for use in the detector. Comparison is made with a 'traditional' radiator, which is a periodic structure of plastic foils. (orig.)

Impact of pannus formation on hemodynamic dysfunction of prosthetic aortic valve: pannus extent and its relationship to prosthetic valve motion and degree of stenosis.

Science.gov (United States)

Koo, Hyun Jung; Ha, Hojin; Kang, Joon-Won; Kim, Jeong A; Song, Jae-Kwan; Kim, Hwa Jung; Lim, Tae-Hwan; Yang, Dong Hyun

2018-02-19

Although pannus is an important cause of prosthetic valve dysfunction, the minimum pannus size that can induce hemodynamic dysfunction has not yet been determined. This study investigated the correlation between the limitation of motion (LOM) of the prosthetic valve and pannus extent and determined the pannus extent that could induce severe aortic stenosis. This study included 49 patients who underwent mechanical aortic valve replacement (AVR) and showed pannus on cardiac computed tomography (CT). Pannus width, ratio of pannus width to valve diameter, pannus area, effective orifice area, encroachment ratio by pannus, pannus involvement angle and percent LOM of mechanical valves were evaluated on CT. Transvalvular peak velocity (TPV) and transvalvular pressure gradient (TPG) were measured by transesophageal echocardiography to determine the degree of aortic stenosis. The relationship between percent LOM of the prosthetic valve and pannus extent and the cut-off of pannus extent required to induce severe aortic stenosis were evaluated. The mean interval between AVR and pannus formation was 11 years and was longer in patients with than without severe aortic stenosis (14.0 vs. 7.3 years). On CT, the percent LOM of the prosthetic valve was significantly associated with the extent of pannus only in patients with pannus involvement angle > 180° (r = 0.55-0.68, P Pannus width, effective orifice area, and encroachment ratio were significantly associated with increased TPV and TPG (r = 0.51-0.62, P Pannus width > 3.5 mm, pannus width/valve inner diameter > 0.15, and encroachment ratio > 0.14 were significantly associated with severe aortic stenosis (TPV > 4 m/s; mean TPG ≥ 35 mmHg), with c-indices of 0.74-079 (P pannus extent parameters are good indicators of significant hemodynamic changes with increased TPV and mean TPG.

A novel rapid direct haemagglutination-inhibition assay for measurements of humoral immune response against non-haemagglutinating Fowlpox virus strains in vaccinated chickens.

Science.gov (United States)

Wambura, Philemon N; Mzula, Alexanda

2017-10-01

Fowlpox (FP) is a serious disease in chickens caused by Fowlpox virus (FPV). One method currently used to control FPV is vaccination followed by confirmation that antibody titres are protective using the indirect haemagglutination assay (IHA). The direct haemagglutination inhibition (HI) assay is not done because most FPV strains do not agglutinate chicken red blood cells (RBCs). A novel FPV strain TPV-1 which agglutinates chicken RBCs was discovered recently and enabled a direct HI assay to be conducted using homologous sera. This study is therefore aimed at assessing the direct HI assay using a recently discovered novel haemagglutinating FPV strain TPV-1 in chickens vaccinated with a commercial vaccine containing a non-haemagglutinating FPV.Chicks vaccinated with FPV at 1 day-old had antibody geometric mean titres (GMT) of log 2 3.7 at 7 days after vaccination and log 2 8.0 at 28 days after vaccination when tested in the direct HI. Chickens vaccinated at 6 weeks-old had antibody geometric mean titres (GMT) of log 2 5.0 at 7 days after vaccination and log 2 8.4 at 28 days after vaccination when tested in the direct HI. The GMT recorded 28 days after vaccination was slightly higher in chickens vaccinated at 6-week-old than in chicks vaccinated at one-day-old. However, this difference was not significant (P > 0.05). All vaccinated chickens showed "takes". No antibody response to FPV and "takes" were detected in unvaccinated chickens (GMT 0.05). These findings indicate that a simple and rapid direct HI assay using the FPV TPV-1 strain as antigen may be used to measure antibody levels in chickens vaccinated with non-haemagglutinating strains of FPV, and that the titres are comparable to those obtained by indirect IHA.

Impact of Physical and Relational Peer Victimization on Depressive Cognitions in Children and Adolescents

Science.gov (United States)

Sinclair, Keneisha R.; Cole, David A.; Dukewich, Tammy; Felton, Julia; Weitlauf, Amy S.; Maxwell, Melissa A.; Tilghman-Osborne, Carlos; Jacky, Amy

2012-01-01

The purpose of this study is to find longitudinal evidence of the effect of targeted peer victimization (TPV) on depressive cognitions as a function of victimization type and gender. Prospective relations of physical and relational peer victimization to positive and negative self-cognitions were examined in a 1-year, 2-wave longitudinal study.…

Driving Roles of Tropospheric and Stratospheric Thermal Anomalies in Intensification and Persistence of the Arctic Superstorm in 2012

Science.gov (United States)

Tao, Wei; Zhang, Jing; Fu, Yunfei; Zhang, Xiangdong

2017-10-01

Intense synoptic-scale storms have been more frequently observed over the Arctic during recent years. Specifically, a superstorm hit the Arctic Ocean in August 2012 and preceded a new record low Arctic sea ice extent. In this study, the major physical processes responsible for the storm's intensification and persistence are explored through a series of numerical modeling experiments with the Weather Research and Forecasting model. It is found that thermal anomalies in troposphere as well as lower stratosphere jointly lead to the development of this superstorm. Thermal contrast between the unusually warm Siberia and the relatively cold Arctic Ocean results in strong troposphere baroclinicity and upper level jet, which contribute to the storm intensification initially. On the other hand, Tropopause Polar Vortex (TPV) associated with the thermal anomaly in lower stratosphere further intensifies the upper level jet and accordingly contributes to a drastic intensification of the storm. Stacking with the enhanced surface low, TPV intensifies further, which sustains the storm to linger over the Arctic Ocean for an extended period.

Radiation and radiation protection

International Nuclear Information System (INIS)

Landfermann, H.H.; Solbach, C.

1992-11-01

The brochure explains the major types of radiation, the radiation sources, effects, uses, and risks, as well as the regulatory system adopted by the government in order to keep the risks as low as possible. (orig./DG) [de

Effects of radiation-counselling convergence education on radiation awareness

International Nuclear Information System (INIS)

Seoung, Youl Hun

2017-01-01

The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit

Effects of radiation-counselling convergence education on radiation awareness

Energy Technology Data Exchange (ETDEWEB)

Seoung, Youl Hun [Dept. of Radiological Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of)

2017-06-15

The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit.

Operational radiation protection and radiation protection training

International Nuclear Information System (INIS)

Kraus, W.

1989-01-01

The radiation protection system in the German Democratic Republic (GDR) is reviewed. The competent authority (the SAAS) and its systems of licensing and supervision are described. Discussion covers the role of the Radiation Protection Officer, the types of radiation monitoring, medical surveillance programs and the classification of workers and work areas. Unusual occurrences in the GDR, 1963-1976, are presented and the occupational radiation protection problems at some specific types of workplaces are discussed. The GDR's system of training in radiation protection and nuclear safety is described. 5 figs., 18 tabs

Limits to solar power conversion efficiency with applications to quantum and thermal systems

Science.gov (United States)

Byvik, C. E.; Buoncristiani, A. M.; Smith, B. T.

1983-01-01

An analytical framework is presented that permits examination of the limit to the efficiency of various solar power conversion devices. Thermodynamic limits to solar power efficiency are determined for both quantum and thermal systems, and the results are applied to a variety of devices currently considered for use in space systems. The power conversion efficiency for single-threshold energy quantum systems receiving unconcentrated air mass zero solar radiation is limited to 31 percent. This limit applies to photovoltaic cells directly converting solar radiation, or indirectly, as in the case of a thermophotovoltaic system. Photoelectrochemical cells rely on an additional chemical reaction at the semiconductor-electrolyte interface, which introduces additional second-law demands and a reduction of the solar conversion efficiency. Photochemical systems exhibit even lower possible efficiencies because of their relatively narrow absorption bands. Solar-powered thermal engines in contact with an ambient reservoir at 300 K and operating at maximum power have a peak conversion efficiency of 64 percent, and this occurs for a thermal reservoir at a temperature of 2900 K. The power conversion efficiency of a solar-powered liquid metal magnetohydrodydnamic generator, a solar-powered steam turbine electric generator, and an alkali metal thermoelectric converter is discussed.

Genetic parameters for different measures of feed efficiency and related traits in boars of three pig breeds

DEFF Research Database (Denmark)

Do, Duy Ngoc; Strathe, Anders Bjerring; Jensen, Just

2013-01-01

) to 0.67 (LL) for BF, and from 0.13 (DD) to 0.19 (YY) for body conformation. Feeding behavior traits including DFI, number of visits to feeder per day (NVD), total time spent eating per day (TPD), feed intake rate (FR), feed intake per visit (FPV), and time spent eating per visit (TPV) were moderately...

Interaction of hyperthermia and radiation: radiation quality

International Nuclear Information System (INIS)

Loshek, D.D.; Orr, J.S.; Solomonidis, E.

1981-01-01

Cell-survival data were collected to determine the survival response of asynchronous CHO cells subject to radiation and hyperthermia. The irradiation was at room temperature 100 minutes before exposure to hyperthermia at 42 0 C. The survival response to the combination of these two agents is expressed by means of a survival surface, a three-dimensional concept relating cell survival to heat dose and radiation dose. The survival surface could be approximately described by a survival model comprising three components of cell killing: the unperturbed radiation component, the unperturbed hyperthermia component and the interaction component. The dependence of the radiation component and the interaction component on radiation quality were investigated by irradiating with either 60 Co γ rays, 250 kV X rays or 14.7 MeV neutrons. An analysis suggests that the interaction component and the radiation component exhibit similar dependencies on radiation quality both for the deposition of damage and the repair or accumulation of that damage. (U.K.)

Natural radiation

International Nuclear Information System (INIS)

Feliciano, Vanusa Maria Delage

2016-01-01

Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included

Radiation safety

International Nuclear Information System (INIS)

Jain, Priyanka

2014-01-01

The use of radiation sources is a privilege; in order to retain the privilege, all persons who use sources of radiation must follow policies and procedures for their safe and legal use. The purpose of this poster is to describe the policies and procedures of the Radiation Protection Program. Specific conditions of radiation safety require the establishment of peer committees to evaluate proposals for the use of radionuclides, the appointment of a radiation safety officer, and the implementation of a radiation safety program. In addition, the University and Medical Centre administrations have determined that the use of radiation producing machines and non-ionizing radiation sources shall be included in the radiation safety program. These Radiation Safety policies are intended to ensure that such use is in accordance with applicable State and Federal regulations and accepted standards as directed towards the protection of health and the minimization of hazard to life or property. It is the policy that all activities involving ionizing radiation or radiation emitting devices be conducted so as to keep hazards from radiation to a minimum. Persons involved in these activities are expected to comply fully with the Canadian Nuclear Safety Act and all it. The risk of prosecution by the Department of Health and Community Services exists if compliance with all applicable legislation is not fulfilled. (author)

The analysis of radiation exposure of hospital radiation workers

International Nuclear Information System (INIS)

Jeong, Tae Sik; Shin, Byung Chul; Moon, Chang Woo; Cho, Yeong Duk; Lee, Yong Hwan; Yum, Ha Yong

2000-01-01

This investigation was performed in order to improve the health care of radiation workers, to predict a risk, to minimize the radiation exposure hazard to them and for them to realize radiation exposure danger when they work in radiation area in hospital. The documentations checked regularly for personal radiation exposure in four university hospitals in Pusan city in Korea between January 1, 1993 and December 31, 1997 were analyz ed. There were 458 persons in this documented but 111 persons who worked less then one year were excluded and only 347 persons were included in this study. The average of yearly radiation exposure of 347 persons was 1.52±1.35 mSv. Though it was less than 5OmSv, the limitaion of radiation in law but 125 (36%) people received higher radiation exposure than non-radiation workers. Radiation workers under 30 year old have received radiation exposure of mean 1.87±1.01 mSv/year, mean 1.22±0.69 mSv between 31 and 40 year old and mean 0.97±0.43 mSv/year over, 41year old (p<0.001). Men received mean 1.67±1.54 mSv/year were higher than women who received mean 1.13±0.61 mSv/year (p<0.01). Radiation exposure in the department of nuclear medicine department in spite of low energy sources is higher than other departments that use radiations in hospital (p<0.05). And the workers who received mean 3.69±1.81 mSv/year in parts of management of radiation sources and injection of sources to patient receive high radiation exposure in nuclear medicine department (0<0.01). In department of diagnostic radiology high radiation exposure is in barium enema rooms where workers received mean 3.74±1.74 mSv/year and other parts where they all use fluoroscopy such as angiography room of mean 1.17±0.35 mSv/year and upper gastrointestinal room of mean 1.74±1.34 mSv/year represented higher radiation exposure than average radiation exposure in diagnostic radiology (p<0.01). Doctors and radiation technologists received higher radiation exposure of each mean 1.75±1

Radiation exposure analysis of female nuclear medicine radiation workers

Energy Technology Data Exchange (ETDEWEB)

Lee, Ju Young [Dept. of Biomedical Engineering Graduate School, Chungbuk National University, Cheongju (Korea, Republic of); Park, Hoon Hee [Dept. of Radiological Technologist, Shingu College, Sungnam (Korea, Republic of)

2016-06-15

In this study, radiation workers who work in nuclear medicine department were analyzed to find the cause of differences of radiation exposure from General Characteristic, Knowledge, Recognition and Conduct, especially females working on nuclear medicine radiation, in order to pave the way for positive defense against radiation exposure. The subjects were 106 radiation workers who were divided into two groups of sixty-four males and forty-two females answered questions about their General Characteristic, Knowledge, Recognition, Conduct, and radiation exposure dose which was measured by TLD (Thermo Luminescence Dosimeter). The results of the analysis revealed that as the higher score of knowledge and conduct was shown, the radiation exposure decreased in female groups, and as the higher score of conduct was shown, the radiation exposure decreased in male groups. In the correlation analysis of female groups, the non-experienced in pregnancy showed decreasing amount of radiation exposure as the score of knowledge and conduct was higher and the experienced in pregnancy showed decreasing amount of radiation exposure as the score of recognition and conduct was higher. In the regression analysis on related factors of radiation exposure dose of nuclear medicine radiation workers, the gender caused the meaningful result and the amount of radiation exposure of female groups compared to male groups. In the regression analysis on related factors of radiation exposure dose of female groups, the factor of conduct showed a meaningful result and the amount of radiation exposure of the experienced in pregnancy was lower compared to the non-experienced. The conclusion of this study revealed that radiation exposure of female groups was lower than that of male groups. Therefore, male groups need to more actively defend themselves against radiation exposure. Among the female groups, the experienced in pregnancy who have an active defense tendency showed a lower radiation exposure. Thus

Radiation exposure analysis of female nuclear medicine radiation workers

International Nuclear Information System (INIS)

Lee, Ju Young; Park, Hoon Hee

2016-01-01

In this study, radiation workers who work in nuclear medicine department were analyzed to find the cause of differences of radiation exposure from General Characteristic, Knowledge, Recognition and Conduct, especially females working on nuclear medicine radiation, in order to pave the way for positive defense against radiation exposure. The subjects were 106 radiation workers who were divided into two groups of sixty-four males and forty-two females answered questions about their General Characteristic, Knowledge, Recognition, Conduct, and radiation exposure dose which was measured by TLD (Thermo Luminescence Dosimeter). The results of the analysis revealed that as the higher score of knowledge and conduct was shown, the radiation exposure decreased in female groups, and as the higher score of conduct was shown, the radiation exposure decreased in male groups. In the correlation analysis of female groups, the non-experienced in pregnancy showed decreasing amount of radiation exposure as the score of knowledge and conduct was higher and the experienced in pregnancy showed decreasing amount of radiation exposure as the score of recognition and conduct was higher. In the regression analysis on related factors of radiation exposure dose of nuclear medicine radiation workers, the gender caused the meaningful result and the amount of radiation exposure of female groups compared to male groups. In the regression analysis on related factors of radiation exposure dose of female groups, the factor of conduct showed a meaningful result and the amount of radiation exposure of the experienced in pregnancy was lower compared to the non-experienced. The conclusion of this study revealed that radiation exposure of female groups was lower than that of male groups. Therefore, male groups need to more actively defend themselves against radiation exposure. Among the female groups, the experienced in pregnancy who have an active defense tendency showed a lower radiation exposure. Thus

Multiscale bilateral filtering for improving image quality in digital breast tomosynthesis

Science.gov (United States)

Lu, Yao; Chan, Heang-Ping; Wei, Jun; Hadjiiski, Lubomir M.; Samala, Ravi K.

2015-01-01

Purpose: Detection of subtle microcalcifications in digital breast tomosynthesis (DBT) is a challenging task because of the large, noisy DBT volume. It is important to enhance the contrast-to-noise ratio (CNR) of microcalcifications in DBT reconstruction. Most regularization methods depend on local gradient and may treat the ill-defined margins or subtle spiculations of masses and subtle microcalcifications as noise because of their small gradient. The authors developed a new multiscale bilateral filtering (MSBF) regularization method for the simultaneous algebraic reconstruction technique (SART) to improve the CNR of microcalcifications without compromising the quality of masses. Methods: The MSBF exploits a multiscale structure of DBT images to suppress noise and selectively enhance high frequency structures. At the end of each SART iteration, every DBT slice is decomposed into several frequency bands via Laplacian pyramid decomposition. No regularization is applied to the low frequency bands so that subtle edges of masses and structured background are preserved. Bilateral filtering is applied to the high frequency bands to enhance microcalcifications while suppressing noise. The regularized DBT images are used for updating in the next SART iteration. The new MSBF method was compared with the nonconvex total p-variation (TpV) method for noise regularization with SART. A GE GEN2 prototype DBT system was used for acquisition of projections at 21 angles in 3° increments over a ±30° range. The reconstruction image quality with no regularization (NR) and that with the two regularization methods were compared using the DBT scans of a heterogeneous breast phantom and several human subjects with masses and microcalcifications. The CNR and the full width at half maximum (FWHM) of the line profiles of microcalcifications and across the spiculations within their in-focus DBT slices were used as image quality measures. Results: The MSBF method reduced contouring artifacts

Sound radiation quantities arising from a resilient circular radiator

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2009-01-01

Power series expansions in ka are derived for the pressure at the edge of a radiator, the reaction force on the radiator, and the total radiated power arising from a harmonically excited, resilient, flat, circular radiator of radius a in an infinite baffle. The velocity profiles on the radiator are

Ionizing radiation

International Nuclear Information System (INIS)

Kruger, J.

1989-01-01

Ionizing radiation results in biological damage that differs from other hazardous substances and is highly dangerous to man. Ionizing radiation cannot be perceived by man's sense organs and the biological damage cannot be detected immediately afterwards (except in very high doses). Every human being is exposed to low doses of radiation. The structure of the atom; sources of ionizing radiation; radiation units; biological effects; norms for radiation protection; and the national control in South Africa are discussed. 1 fig., 5 refs

Radiation injuries/ionizing radiation

International Nuclear Information System (INIS)

Gooden, D.S.

1991-01-01

This book was written to aid trial attorneys involved in radiation litigation. Radiologists and medical physicists will also find it helpful as they prepare for trial, either as a litigant or an expert witness. Two chapters present checklists to guide attorneys for both plaintiffs and defendants. Gooden titles these checklists Elements of Damages and Elements of Proof and leads the reader to conclusions about each of these. One section that will be particularly helpful to attorneys contains sample interrogatories associated with a case of alleged radiation exposure resulting in a late radiation injury. There are interrogatories for the plaintiff to ask the defendant and for the defendant to ask the plaintiff

Radiation exposure and radiation hazards of human population. Pt. 1

International Nuclear Information System (INIS)

Jacobi, W.

1982-01-01

The present Part I provides a survey on the various sources of natural and artificial radiation exposure of human population. Furthermore, biological radiation effects and radiation damages are surveyed. In an appendix, radiation types, radiation doses, and radiation dose units are explained. (orig./GSCH) [de

Proposing a simple radiation scale for the public: Radiation index

Energy Technology Data Exchange (ETDEWEB)

Cho, Gyu Seong; Kim, Jong Hyun [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Park, Tae Soon [Center for Ionizing Radiation, Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Cho, Kunwoo [Dept. of Natural Radiation Safety, Korea Institute of Nuclear Safety (KINS), Daejeon (Korea, Republic of)

2017-04-15

A new radiation scale is proposed. With empathy toward the vast majority of people who are not well versed in radiation and related matters, and thus suffering from misunderstanding that breeds unnecessary fear of radiation, the aim of proposing a new radiation scale, radiation index (RAIN), is to put the general public at ease with the concept of radiation. RAIN is defined in dimensionless numbers that relate any specific radiation dose to a properly defined reference level. As RAIN is expressed in plain numbers without an attached scientific unit, the public will feel comfortable with its friendly look, which in turn should help them understand radiation dose levels easily and allay their anxieties about radiation. The expanded awareness and proper understanding of radiation will empower the public to feel that they are not hopeless victims of radiation. The correspondence between RAIN and the specific accumulated dose is established. The equivalence will allow RAIN to serve as a common language of communication for the general public with which they can converse with radiation experts to discuss matters related to radiation safety, radiation diagnosis and therapy, nuclear accidents, and other related matters. Such fruitful dialogues will ultimately enhance public acceptance of radiation and associated technologies.

Proposing a simple radiation scale for the public: Radiation index

International Nuclear Information System (INIS)

Cho, Gyu Seong; Kim, Jong Hyun; Park, Tae Soon; Cho, Kunwoo

2017-01-01

A new radiation scale is proposed. With empathy toward the vast majority of people who are not well versed in radiation and related matters, and thus suffering from misunderstanding that breeds unnecessary fear of radiation, the aim of proposing a new radiation scale, radiation index (RAIN), is to put the general public at ease with the concept of radiation. RAIN is defined in dimensionless numbers that relate any specific radiation dose to a properly defined reference level. As RAIN is expressed in plain numbers without an attached scientific unit, the public will feel comfortable with its friendly look, which in turn should help them understand radiation dose levels easily and allay their anxieties about radiation. The expanded awareness and proper understanding of radiation will empower the public to feel that they are not hopeless victims of radiation. The correspondence between RAIN and the specific accumulated dose is established. The equivalence will allow RAIN to serve as a common language of communication for the general public with which they can converse with radiation experts to discuss matters related to radiation safety, radiation diagnosis and therapy, nuclear accidents, and other related matters. Such fruitful dialogues will ultimately enhance public acceptance of radiation and associated technologies

Thermal to Electric Energy Conversion for Cyclic Heat Loads

Science.gov (United States)

Whitehead, Benjamin E.

Today, we find cyclic heat loads almost everywhere. When we drive our cars, the engines heat up while we are driving and cool while parked. Processors heat while the computer is in use at the office and cool when idle at night. The sun heats the earth during the day and the earth radiates that heat into space at night. With modern technology, we have access to a number of methods to take that heat and convert it into electricity, but, before selecting one, we need to identify the parameters that inform decision making. The majority of the parameters for most systems include duty cycle, total cost, weight, size, thermal efficiency, and electrical efficiency. However, the importance of each of these will depend on the application. Size and weight take priority in a handheld device, while efficiency dominates in a power plant, and duty cycle is likely to dominate in highly demanding heat pump applications. Over the past decade, developments in semiconductor technology has led to the creation of the thermoelectric generator. With no moving parts and a nearly endlessly scalable nature, these generators present interesting opportunities for taking advantage of any source of waste heat. However, these generators are typically only capable of 5-8% efficiency from conversion of thermal to electric energy. [1]. Similarly, advancements in photovoltaic cells has led to the development of thermophotovoltaics. By heating an emitter to a temperature so it radiates light, a thermophotovoltaic cell then converts that light into electricity. By selecting materials that emit light in the optimal ranges of the appropriate photovoltaic cells, thermophotovoltaic systems can potentially exceed the current maximum of 10% efficiency. [2]. By pressurizing certain metal powders with hydrogen, hydrogen can be bound to the metal, creating a metal hydride, from which hydrogen can be later re-extracted under the correct pressure and temperature conditions. Since this hydriding reaction is

Radiation versus radiation: nuclear energy in perspective

International Nuclear Information System (INIS)

Gonzalez, A.J.; Anderer, J.

1989-01-01

This paper seeks to provide a proper perspective on radiation exposures from nuclear energy. Instead of comparing these exposures with other pollutants, natural and man-made, it assesses the radiation doses that result from the human environment and from the entire fuel cycle associated with nuclear generated electricity. It explores radiation versus radiation, not only in terms of absolute levels but, more importantly, of the enormous variability characterizing many radiation sources. The quantitative findings and their implications are meant to contribute to a balanced understanding of the radiological impact of nuclear energy, and so to help to bridge the information gap that is perceived to exist on this issue. The 1988 Unscear report and its seven scientific annexes provide an authoritative and dispassionate factual basis for examining radiation levels from all sources, natural and man-made. It is the main source for this paper. (author)

Roles of radiation chemistry in development and research of radiation biology

International Nuclear Information System (INIS)

Min Rui

2009-01-01

Radiation chemistry acts as a bridge connecting radiation physics with radiation biology in spatial and temporal insight. The theory, model, and methodology coming from radiation chemistry play an important role in the research and development of radiation biology. The chemical changes induced by ionizing radiation are involved not only in early event of biological effects caused by ionizing radiation but in function radiation biology, such as DNA damage and repair, sensitive modification, metabolism and function of active oxygen and so on. Following the research development of radiation biology, systems radiation biology, accurate quality and quantity of radiation biology effects need more methods and perfect tools from radiation chemistry. (authors)

Radiation protection guidelines for radiation emergencies

International Nuclear Information System (INIS)

Lessard, E.T.; Meinhold, C.B.

1986-01-01

The system of dose limitation and present guidance for emergency workers and guidance for intervention on behalf of the public are discussed. There are three elements for the system of dose limitation: justification, optimization and dose limits. The first element is basically a political process in this country. Justification is based on a risk-benefit analysis, and justification of the use of radioactive materials or radiation is generally not within the authority of radiation protection managers. Radiation protection managers typically assess detriments or harm caused by radiation exposure and have very little expertise in assessing the benefits of a particular practice involving nuclear material

Radiation and radiation effects; Strahlung und Strahlenwirkung

Energy Technology Data Exchange (ETDEWEB)

Neumaier, S. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Arbeitsgruppe Strahlenschutz; Janssen, H. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Abt. Ionisierende Strahlung

2006-12-15

The average dose incurred by the German population is about 4 millisievert p.a., about half of which results from natural radiation sources. The second half is caused nearly completely by medical applications. Only a very small fraction of the annual dose results from technical applications. This special issue of PTB focuses on the measuring problems relating to natural radiation sources and technical applications of ionizing radiation. The current contribution also outlines some important aspects of radiation exposure from medical applications. (orig.)

Use of synchrotron radiation in radiation biology research

International Nuclear Information System (INIS)

Yamada, Takeshi

1981-01-01

Synchrotron radiation (SR) holds great expectation as a new research tool in the new areas of material science, because it has the continuous spectral distribution from visible light to X-ray, and its intensity is 10 2 to 10 3 times as strong as that of conventional radiation sources. In the National Laboratory for High Energy Physics, a synchrotron radiation experimental facility has been constructed, which will start operation in fiscal 1982. With this SR, the photons having the wavelength in undeveloped region from vacuum ultraviolet to soft X-ray are obtained as intense mono-wavelength light. The SR thus should contribute to the elucidation of the fundamentals in the biological action of radiation. The following matters are described: synchrotron radiation, experimental facility using SR, electron storage ring, features of SR, photon factory plan and synchrotron radiation experimental facility, utilization of SR in radiation biology field. (J.P.N.)

Technical sheets of ionizing radiations. 2. Non-ionizing radiations

International Nuclear Information System (INIS)

Anon.

1975-01-01

The biological effects of different non-ionizing radiations are studied: ultra-violet radiation, visible radiation, infrared radiation, micrometric waves, ultrasonics. In spite of their apparent diversity these radiations are similar in their physico-chemical effects, but in view of their widely varying production methods and types of application each type is considered separately. It is pointed out that no organization resembling the CIPR exists in the field of non-ionizing radiations, the result being a great disparity amongst the different legislations in force [fr

Metallic layer-by-layer photonic crystals for linearly-polarized thermal emission and thermophotovoltaic device including same

Science.gov (United States)

Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P.

2016-07-26

Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 .mu.m, as well as high emissivity up to 0.65 at a wavelength of 3.7 .mu.m. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization.

Gravitational radiation resistance, radiation damping and field fluctuations

International Nuclear Information System (INIS)

Schaefer, G.

1981-01-01

Application is made of two different generalised fluctuation-dissipation theorems and their derivations to the calculation of the gravitational quadrupole radiation resistance using the radiation-reaction force given by Misner, Thorne and Wheeler (Gravitation (San Francisco: Freeman) ch 36,37 (1973)) and the usual tidal force on one hand and the tidal force and the free gravitational radiation field on the other hand. The quantum-mechanical version (including thermal generalisations) of the well known classical quadrupole radiation damping formula is obtained as a function of the radiation resistance. (author)

Radiation protection and the safety of radiation sources

International Nuclear Information System (INIS)

1996-01-01

These Safety Fundamentals cover the protection of human beings against ionizing radiation (gamma and X rays and alpha, beta and other particles that can induce ionization as they interact with biological materials), referred to herein subsequently as radiation, and the safety of sources that produce ionizing radiation. The Fundamentals do not apply to non-ionizing radiation such as microwave, ultraviolet, visible and infrared radiation. They do not apply either to the control of non-radiological aspects of health and safety. They are, however, part of the overall framework of health and safety

Development of natural radiation model for evaluation of background radiation in radiation portal monitor

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Bum; Lee, Jin Hyung; Moon, Myung Kook [Radioisotope Research and Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-11-15

In ports and airports, radiation portal monitors (RPM) are deployed to detect illicit radioactive materials. Detected gamma rays in a RPM include background radiation and radiation from a freight. As a vehicle moves through the RPM, the vehicle causes the fluctuations in the natural background radiation signal, which ranges of up to 30%. The fluctuation increases the uncertainty of detection signal and can be a cause of RPM false alarm. Therefore, it is important to evaluate background radiation as well as radiation from a container. In this paper, a natural background radiation model was developed to evaluate RPM. To develop natural background radiation model, a Monte Carlo simulation was performed and compared with experimental measurements from a RPM for {sup 40}K, {sup 232}Th series, and {sup 235}U series, which are major sources of natural background radiation. For a natural radiation source, we considered a cylindrical soil volume with 300 m radius and 1 m depth, which was estimated as the maximum range affecting the RPM by MCNP6 simulation. The volume source model was converted to surface source by using MCNP SSW card for computational efficiency. The computational efficiency of the surface source model was improved to approximately 200 times better than that of the volume source model. The surface source model is composed of a hemisphere with 20 m radius in which the RPM and container are modelled. The natural radiation spectrum from the simulation was best fitted to the experimental measurement when portions of {sup 40}K, {sup 232}Th series, and {sup 235}U series were 0.75, 0.0636, and 0.0552 Bq·g{sup -1}, respectively. For gross counting results, the difference between simulation and experiment was around 5%. The background radiation model was used to evaluate background suppression from a 40 ft container with 7.2 m·s{sup -1} speed. In further study, background models and freight models for RPM in real container ports will be developed and applied to

From radiation chemistry to radiation engineering

International Nuclear Information System (INIS)

Ballantine, D.S.

1976-01-01

During the past 25 years there has been a steady recognition that radiation in the form of electrons or gamma rays can offer positive advantages as a processing technology. Underlying this process industry, and largely responsible for its success, are significant contributions from the field of basic and applied radiation chemistry. In this paper it is attempted to relate fundamental radiation chemistry studies directly to the practical engineering applications

Radiation and man. From radiology to radiation protection

International Nuclear Information System (INIS)

2005-04-01

Man first became aware of the invisible radiation surrounding him in 1895, when Wilhelm Roentgen showed that a photographic plate could be affected by an invisible radiation capable of passing through matter. He called this radiation 'X-rays' from X, the unknown. Doctors immediately saw the usefulness of this type of radiation and began to use it in medical research. This was the birth of radiology. 'Mankind has been exposed to radiation since his first appearance on Earth. We first became aware of this at the end of the 19. century'. However, it was not long before some of the doctors and radiologists treating their patients with X-rays began to fall ill. It began to be understood that exposure to high doses of radiation was dangerous and protective measures were necessary. From the 1920's onwards, international commissions were established to specify regulations for the use of radiation and for the radiological protection of personnel. (authors)

Radiation hormesis and its potential to manage radiation injuries

International Nuclear Information System (INIS)

Bala, Madhu; Mathew, Lazar

2000-01-01

The term radiation hormesis explains stimulatory or beneficial effects of low dose radiation exposure, which cannot be predicted by extrapolation of detrimental or lethal effects of high dose radiation exposure. Although beneficial effects of low doses of radiation were observed soon after discovery of x-rays and radioactivity, studies remained inconclusive until recently, due to (i) inadequate statistical planning of experiments conducted in early part of the 20th century; and (ii) poor dose monitoring. Recently (1980s onwards), large scale, systematic epidemiological and experimental studies with a number of diverse systems have demonstrated existence of radiation hormesis beyond doubt. It is pointed out that the hormetic effects of radiation have not been successfully exploited so far for human benefits, primarily because underlying molecular mechanisms are poorly understood. It is argued that with more and more studies, it is becoming evident that radiation hormesis is not merely physiological adaptation, but a genetically regulated phenomenon and involves de novo synthesis of proteins. Role of these proteins in induction of radiation hormesis is the current area of research in a number of world-renowned laboratories. The first part of this review elucidates the shifts in paradigms on radiation effects in the 20th century and the later portion presents a brief on underlying molecular mechanisms of radiation hormesis and their implications towards management of radiation injuries. (author)

Radiation signatures

International Nuclear Information System (INIS)

McGlynn, S.P.; Varma, M.N.

1992-01-01

A new concept for modelling radiation risk is proposed. This concept is based on the proposal that the spectrum of molecular lesions, which we dub ''the radiation signature'', can be used to identify the quality of the causal radiation. If the proposal concerning radiation signatures can be established then, in principle, both prospective and retrospective risk determination can be assessed on an individual basis. A major goal of biophysical modelling is to relate physical events such as ionization, excitation, etc. to the production of radiation carcinogenesis. A description of the physical events is provided by track structure. The track structure is determined by radiation quality, and it can be considered to be the ''physical signature'' of the radiation. Unfortunately, the uniqueness characteristics of this signature are dissipated in biological systems in ∼10 -9 s. Nonetheless, it is our contention that this physical disturbance of the biological system eventuates later, at ∼10 0 s, in molecular lesion spectra which also characterize the causal radiation. (author)

Radiation protection

International Nuclear Information System (INIS)

Jain, Aman; Sharma, Shivam; Parasher, Abhishek

2014-01-01

Radiation dose measurement, field of radiobiology, is considered to be critical factor for optimizing radiation protection to the health care practitioners, patients and the public. This lead to equipment that has dose - area product meters permanently installed. In many countries and even institution, the range of equipment is vast and with the opportunity for radiation protection and dose recording varies considerably. Practitioners must move with the changed demands of radiation protection but in many cases without assistance of modern advancements in technology Keeping the three basic safety measures Time, Dose and Shielding we can say 'Optimum dose is safe dose' instead of 'No dose is safe dose'. The purpose enclosed within the title 'Radiation Protection'. The use of radiation is expanding widely everyday around the world and crossing boundaries of medical imaging, diagnostic and. The way to get the ''As low as reasonably achievable' is only achievable by using methodology of radiation protection and to bring the concern of general public and practitioners over the hazards of un-necessary radiation dose. Three basic principles of radiation protection are time, distance and shielding. By minimizing the exposure time increasing the distance and including the shielding we can reduce the optimum range of dose. The ability of shielding material to attenuate radiation is generally given as half value layer. This is the thickness of the material which will reduce the amount of radiation by 50%. Lab coat and gloves must be worn when handling radioactive material or when working in a labeled radiation work area. Safety glasses or other appropriate splash shields should be used when handling radioactive material. 1. Reached to low dose level to occupational workers, public as per prescribed dose limit. 2. By mean of ALARA principle we achieved the protection from radiation besides us using the radiation for our benefit

Acute radiation syndrome caused by accidental radiation exposure - therapeutic principles

Directory of Open Access Journals (Sweden)

Dörr Harald

2011-11-01

Full Text Available Abstract Fortunately radiation accidents are infrequent occurrences, but since they have the potential of large scale events like the nuclear accidents of Chernobyl and Fukushima, preparatory planning of the medical management of radiation accident victims is very important. Radiation accidents can result in different types of radiation exposure for which the diagnostic and therapeutic measures, as well as the outcomes, differ. The clinical course of acute radiation syndrome depends on the absorbed radiation dose and its distribution. Multi-organ-involvement and multi-organ-failure need be taken into account. The most vulnerable organ system to radiation exposure is the hematopoietic system. In addition to hematopoietic syndrome, radiation induced damage to the skin plays an important role in diagnostics and the treatment of radiation accident victims. The most important therapeutic principles with special reference to hematopoietic syndrome and cutaneous radiation syndrome are reviewed.

Radiation analysis devices, radiation analysis methods, and articles of manufacture

Science.gov (United States)

Roybal, Lyle Gene

2010-06-08

Radiation analysis devices include circuitry configured to determine respective radiation count data for a plurality of sections of an area of interest and combine the radiation count data of individual of sections to determine whether a selected radioactive material is present in the area of interest. An amount of the radiation count data for an individual section is insufficient to determine whether the selected radioactive material is present in the individual section. An article of manufacture includes media comprising programming configured to cause processing circuitry to perform processing comprising determining one or more correction factors based on a calibration of a radiation analysis device, measuring radiation received by the radiation analysis device using the one or more correction factors, and presenting information relating to an amount of radiation measured by the radiation analysis device having one of a plurality of specified radiation energy levels of a range of interest.

Regulation for radiation protection in applications of radiation sources

International Nuclear Information System (INIS)

Sonawane, Avinash U.

2016-01-01

Applications of ionising radiation in multifarious field are increasing in the country for the societal benefits. The national regulatory body ensures safety and security of radiation sources by enforcing provisions in the national law and other relevant rules issued under the principle law. In addition, the enforcement of detailed requirements contained in practice specific safety codes and standard and issuance of safety directives brings effectiveness in ensuring safe handling and secure management of radiation sources. The regulatory requirements for control over radiation sources throughout their life-cycle have evolved over the years from experience gained. Nevertheless, some of the regulatory activities which require special attention have been identified such as the development of regulation to deal with advance emerging radiation technology in applications of radiation in medicine and industry; sustaining continuity in ensuring human resource development programme; inspections of category 3 and 4 disused sources and their safe disposal; measures for controlling transboundary movement of radiation sources. The regulatory measures have been contemplated and are being enforced to deal with the above issues in an effective manner. The complete involvement of the management of radiation facilities, radiation workers and their commitment in establishing and maintaining safety and security culture is essential to handle the radiation sources safely and efficiently at all times

Brain radiation - discharge

Science.gov (United States)

Radiation - brain - discharge; Cancer - brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

Radiation-induced Genomic Instability and Radiation Sensitivity

Energy Technology Data Exchange (ETDEWEB)

Varnum, Susan M.; Sowa, Marianne B.; Kim, Grace J.; Morgan, William F.

2013-01-19

The obvious relationships between reactive oxygen and nitrogen species, mitochondrial dysfunction, inflammatory type responses and reactive chemokines and cytokines suggests a general stress response induced by ionizing radiation most likely leads to the non-targeted effects described after radiation exposure. We argue that true bystander effects do not occur in the radiation therapy clinic. But there is no question that effects outside the target volume do occur. These “out of field effects” are considered very low dose effects in the context of therapy. So what are the implications of non-targeted effects on radiation sensitivity? The primary goal of therapy is to eradicate the tumor. Given the genetic diversity of the human population, lifestyle and environment factors it is likely some combination of these will influence patient outcome. Non-targeted effects may contribute to a greater or lesser extent. But consider the potential situation involving a partial body exposure due to a radiation accident or radiological terrorism. Non-targeted effects suggest that the tissue at risk for demonstrating possible detrimental effects of radiation exposure might be greater than the volume actually irradiated.

New radiobiological, radiation risk and radiation protection paradigms

International Nuclear Information System (INIS)

Goodhead, Dudley T.

2010-01-01

The long-standing conventional paradigm for radiobiology has formed a logical basis for the standard paradigm for radiation risk of cancer and heritable effects and, from these paradigms, has developed the internationally applied system for radiation protection, but with many simplifications, assumptions and generalizations. A variety of additional radiobiological phenomena that do not conform to the standard paradigm for radiobiology may have potential implications for radiation risk and radiation protection. It is suggested, however, that the current state of knowledge is still insufficient for these phenomena, individually or collectively, to be formulated systematically into a new paradigm for radiobiology. Additionally, there is at present lack of direct evidence of their relevance to risk for human health, despite attractive hypotheses as to how they might be involved. Finally, it remains to be shown how incorporation of such phenomena into the paradigm for radiation protection would provide sufficient added value to offset disruption to the present widely applied system. Further research should aim for better mechanistic understanding of processes such as radiation-induced genomic instability (for all radiation types) and bystander effects (particularly for low-fluence high-LET particles) and also priority should be given to confirmation, or negation, of the relevance of the processes to human health risks from radiation.

Radiation injury

International Nuclear Information System (INIS)

Hubner, K.F.

1988-01-01

Radiation accidents and incidents continue to be of great interest and concern to the public. Issues such as the threat of nuclear war, the Chernobyl reactor accident, or reports of sporadic incidences of accidental radiation exposure keep this interest up and maintain a high level of fear among the public. In this climate of real concern and radiation phobia, physicians should not only be prepared to answer questions about acute or late effects of ionizing radiation, but also be able to participate in the initial assessment and management of individuals who have been exposed to ionizing radiation or contaminated with radioactive material. Some of the key facts about radiation injury and its medical treatment are discussed by the author

Perception of low dose radiation risks among radiation researchers in Korea.

Science.gov (United States)

Seong, Ki Moon; Kwon, TaeWoo; Seo, Songwon; Lee, Dalnim; Park, Sunhoo; Jin, Young Woo; Lee, Seung-Sook

2017-01-01

Expert's risk evaluation of radiation exposure strongly influences the public's risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts' radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual's opinions have often exacerbated the public's confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years' research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects perception of radiation exposure.

Perception of low dose radiation risks among radiation researchers in Korea

Science.gov (United States)

Seo, Songwon; Lee, Dalnim; Park, Sunhoo; Jin, Young Woo; Lee, Seung-Sook

2017-01-01

Expert’s risk evaluation of radiation exposure strongly influences the public’s risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts’ radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual’s opinions have often exacerbated the public’s confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years’ research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at risk perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects risk perception of radiation exposure. PMID:28166286

Radiation protection

International Nuclear Information System (INIS)

Koelzer, W.

1975-01-01

Physical and radiological terms, quantities, and units. Basic principles of radiation protection (ICRP, IAEA, EURATOM, FRG). Biological effects of ionizing radiation. Objectives of practical radiation protection. (HP) [de

Topics in radiation dosimetry radiation dosimetry

CERN Document Server

1972-01-01

Radiation Dosimetry, Supplement 1: Topics in Radiation Dosimetry covers instruments and techniques in dealing with special dosimetry problems. The book discusses thermoluminescence dosimetry in archeological dating; dosimetric applications of track etching; vacuum chambers of radiation measurement. The text also describes wall-less detectors in microdosimetry; dosimetry of low-energy X-rays; and the theory and general applicability of the gamma-ray theory of track effects to various systems. Dose equivalent determinations in neutron fields by means of moderator techniques; as well as developm

Staff radiation exposure in radiation diagnostics

International Nuclear Information System (INIS)

Khakimova, N.U.; Malisheva, E.Yu.; Shosafarova, Sh.G.

2010-01-01

Present article is devoted to staff radiation exposure in radiation diagnostics. Data on staff radiation exposure obtained during 2005-2008 years was analyzed. It was found that average individual doses of staff of various occupations in Dushanbe city for 2008 year are at 0.29-2.16 mSv range. They are higher than the average health indicators but lower than maximum permissible dose. It was defined that paramedical personnel receives the highest doses among the various categories of staff.

Radiation myelopathy

International Nuclear Information System (INIS)

Berlit, P.

1987-01-01

After a review of the world literature, the case histories of 43 patients with radiation myelopathy are analyzed. In 1 patient there was a radiation injury of the medulla oblongata, in 2, cervical, in 28, thoracic, and in 12, lumbosacral. In the medulla oblongata lesion an alternans syndrome resulted. The patients with cervical and thoracic radiation myelopathies presented with a Brown-Sequard syndrome, a spinalis anterior syndrome or a transversal syndrome with pyramidal and spinothalamic tract involvement as the most prominent signs. For this group the term 'pyramidal-spinothalamic radiation myelopathy' is proposed. In lumbosacral radiation lesions a pure anterior horn syndrome may lead to spinothalamic tract involvement and the development of a cauda conus syndrome. The clinical presentation of these cases suggests that the location of the radiation lesion is most likely the region of the conus medullaris. The most frequent initial symptom was dysesthesia; the patients complained of burning pain or a feeling of coldness. Usually the neurological deficits were progressive, in pyramidal-spinothalamic radiation myelopathy over 12 months in average, in lumbosacral radiation lesions up to 10 years. The latent period between the finish of radiation therapy and the first neurological signs was 8 months (median) in cervical and thoracic myelopathy and 33 months in lumbosacral lesions. For the entire group of 43 patients there was an inverse relationship between the radiation dose (ret) and the latent period. A positive relation could be demonstrated between the age of patients at the time of radiation therapy and the latent period. Patients simultaneously receiving cytostatic drugs presented after a longer latent period than the remaining group. (orig./MG)

Development of radiation dose assessment system for radiation accident (RADARAC)

International Nuclear Information System (INIS)

Takahashi, Fumiaki; Shigemori, Yuji; Seki, Akiyuki

2009-07-01

The possibility of radiation accident is very rare, but cannot be regarded as zero. Medical treatments are quite essential for a heavily exposed person in an occurrence of a radiation accident. Radiation dose distribution in a human body is useful information to carry out effectively the medical treatments. A radiation transport calculation utilizing the Monte Carlo method has an advantageous in the analysis of radiation dose inside of the body, which cannot be measured. An input file, which describes models for the accident condition and quantities of interest, should be prepared to execute the radiation transport calculation. Since the accident situation, however, cannot be prospected, many complicated procedures are needed to make effectively the input file soon after the occurrence of the accident. In addition, the calculated doses are to be given in output files, which usually include much information concerning the radiation transport calculation. Thus, Radiation Dose Assessment system for Radiation Accident (RADARAC) was developed to derive effectively radiation dose by using the MCNPX or MCNP code. RADARAC mainly consists of two parts. One part is RADARAC - INPUT, which involves three programs. A user can interactively set up necessary resources to make input files for the codes, with graphical user interfaces in a personnel computer. The input file includes information concerning the geometric structure of the radiation source and the exposed person, emission of radiations during the accident, physical quantities of interest and so on. The other part is RADARAC - DOSE, which has one program. The results of radiation doses can be effectively indicated with numerical tables, graphs and color figures visibly depicting dose distribution by using this program. These results are obtained from the outputs of the radiation transport calculations. It is confirmed that the system can effectively make input files with a few thousand lines and indicate more than 20

Synthesis of Zn-doped TiO{sub 2} microspheres with enhanced photovoltaic performance and application for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhang Yu [State Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry, Jilin University, Changchun 130023 (China); Wang Lingling [State Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry, Jilin University, Changchun 130023 (China); State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 (China); Liu Bingkun; Zhai Jiali; Fan Haimei; Wang Dejun; Lin Yanhong [State Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry, Jilin University, Changchun 130023 (China); Xie Tengfeng, E-mail: xietf@jlu.edu.cn [State Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry, Jilin University, Changchun 130023 (China)

2011-07-15

Highlights: > Near-monodisperse Zn-doped TiO{sub 2} microspheres have been synthesized. > The photovoltaic properties of the samples were examined by SPS, FISPS and TPV measurements. > Surface photovoltage results revealed Zn doping can promote charge transfer in TiO{sub 2} film electrode. - Abstract: Zn-doped TiO{sub 2} microspheres have been synthesized by introducing a trace amount of zinc nitrate hexahydrate to the reaction system. Scanning electron microscope (SEM), field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) have been utilized to characterize the samples. Both surface photovoltage spectroscopy (SPS) technique based on lock-in amplifier and transient photovoltage (TPV) measurement reveal that the slight doping of Zn can promote the separation of photo-generated charges as well as restrain the recombination due to the strong interface built-in electric field and the decreasing of surface trap states. The photovoltaic parameters of dye-sensitized solar cells (DSSCs) based on Zn-doped TiO{sub 2} are significantly better, compared to that of a cell based on undoped TiO{sub 2}. The relation between the performance of DSSCs and their photovoltaic properties is also discussed.

MRI to predict prostate growth and development in children, adolescents and young adults

International Nuclear Information System (INIS)

Ren, Jing; Liu, Huijia; Wen, Didi; Huang, Xufang; Ren, Fang; Huan, Yi; Wang, He

2015-01-01

The purpose of this study was to investigate the use of MRI in predicting prostate growth and development. A total of 1,500 healthy male volunteers who underwent MRI of the pelvis were included in this prospective study. Subjects were divided into five groups according to age (group A, 2-5 years; group B, 6-10 years; group C, 11-15 years; group D, 16-20 years; group E, 21-25 years). Total prostate volume (TPV) as well as prostate central zone (CZ) and peripheral zone (PZ) were measured and evaluated on MRI. Data of the different groups were compared using variance analysis, Scheffe's method, Kruskal-Wallis H-test, and Pearson's correlation. Statistical significance was inferred at P 3 , 0.05 cm 3 , 2.83 cm 3 , 8.32 cm 3, and 11.56 cm 3 , respectively, and the median prostate development scores were 0.08, 0.69, 1.56, 2.38, and 2.74, respectively. Both TPVs and zonal anatomy scores varied significantly among the five groups (P = 0.000). TPV and zonal anatomy score increased with increasing age. MRI provides a reliable quantitative reference for prostate growth and development. (orig.)

Using an accelerometer for analyzing a reach-to-grasp movement after stroke

Directory of Open Access Journals (Sweden)

Stella Maris Michaelsen

2013-12-01

Full Text Available The purpose of this study was using an accelerometer to access the kinematics of reach-to-grasp movements in subjects with hemiparesis. Eight subjects (59.4 ± 6.9 years old with chronic hemiparesis (50.9 ± 25.8 months post-stroke participated in this study. Kinematic assessment was performed using a triaxial accelerometer (EMG Systems, Brazil attached to the subjects' forearm. Ten reach-to-grasp movements of grabbing a 500ml-size bottle were performed by the subjects with the paretic and the non-paretic upper limbs (ULs. The following space-temporal variables were calculated and used to compare the paretic and non-paretic ULs: movement time (MT, time to reach the peak velocity, absolute and relative (TPV and TPV%MT, relative deceleration duration (DEC%MT, time to peak acceleration (TPA and peak hand acceleration (PA. Movements were slower in the paretic UL with increased MT, TPA and DEC. The accelerometer allowed to identify of changes in reaching-to-grasp movements of subjects with hemiparesis. When complex systems are not available, accelerometers can be an alternative to measure UL movements.

Radiation research contracts: Biological effects of small radiation doses

Energy Technology Data Exchange (ETDEWEB)

Hug, O [International Atomic Energy Agency, Division of Health, Safety and Waste Disposal, Vienna (Austria)

1959-04-15

To establish the maximum permissible radiation doses for occupational and other kinds of radiation exposure, it is necessary to know those biological effects which can be produced by very small radiation doses. This particular field of radiation biology has not yet been sufficiently explored. This holds true for possible delayed damage after occupational radiation exposure over a period of many years as well as for acute reactions of the organism to single low level exposures. We know that irradiation of less than 25 Roentgen units (r) is unlikely to produce symptoms of radiation sickness. We have, however, found indications that even smaller doses may produce certain instantaneous reactions which must not be neglected

Radiation metabolomics : a window to high throughput radiation biodosimetry

International Nuclear Information System (INIS)

Rana, Poonam

2016-01-01

In the event of an intentional or accidental release of ionizing radiation in a densely populated area, timely assessment and triage of the general population for radiation exposure is critical. In particular, a significant number of victims may sustain radiation injury, which increases mortality and worsens the overall prognosis of victims from radiation trauma. Availability of a high-throughput noninvasive in vivo biodosimetry tool for assessing the radiation exposure is of particular importance for timely diagnosis of radiation injury. In this study, we describe the potential NMR techniques in evaluating the radiation injury. NMR is the most versatile technique that has been extensively used in the diverse fields of science since its discovery. NMR and biomedical sciences have been going hand in hand since its application in clinical imaging as MRI and metabolic profiling of biofluids was identified. We have established an NMR based metabonomic and in vivo spectroscopy approach to analyse and identify metabolic profile to measure metabolic fingerprint for radiation exposure. NMR spectroscopy experiments were conducted on urine and serum samples collected from mice irradiated with different doses of radiation. Additionally, in vivo NMR spectroscopy was also performed in different region of brains post irradiation in animal model. A number of metabolites associated with energy metabolism, gut flora metabolites, osmolytes, amino acids and membrane metabolism were identified in serum and urine metabolome. Our results illustrated a metabolic fingerprint for radiation exposure that elucidates perturbed physiological functions. Quantitative as well as multivariate analysis/assessment of these metabolites demonstrated dose and time dependent toxicological effect. In vivo spectroscopy from brain showed radiation induced changes in hippocampus region indicating whole body radiation had striking effect on brain metabolism as well. The results of the present work lay a

Validation of radiation dose estimations in VRdose: comparing estimated radiation doses with observed radiation doses

International Nuclear Information System (INIS)

Nystad, Espen; Sebok, Angelia; Meyer, Geir

2004-04-01

The Halden Virtual Reality Centre has developed work-planning software that predicts the radiation exposure of workers in contaminated areas. To validate the accuracy of the predicted radiation dosages, it is necessary to compare predicted doses to actual dosages. During an experimental study conducted at the Halden Boiling Water Reactor (HBWR) hall, the radiation exposure was measured for all participants throughout the test session, ref. HWR-681 [3]. Data from this experimental study have also been used to model tasks in the work-planning software and gather data for predicted radiation exposure. Two different methods were used to predict radiation dosages; one method used all radiation data from all the floor levels in the HBWR (all-data method). The other used only data from the floor level where the task was conducted (isolated data method). The study showed that the all-data method gave predictions that were on average 2.3 times higher than the actual radiation dosages. The isolated-data method gave predictions on average 0.9 times the actual dosages. (Author)

Radiation protection

International Nuclear Information System (INIS)

Ures Pantazi, M.

1994-01-01

This work define procedures and controls about ionizing radiations. Between some definitions it found the following topics: radiation dose, risk, biological effects, international radioprotection bodies, workers exposure, accidental exposure, emergencies and radiation protection

Radiation physics, biophysics, and radiation biology

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.

1993-05-01

Research at the Center for Radiological Research is a multidisciplenary blend of physics, chemistry and biology aimed at understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. The focus is increased on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights of the program from the past year are described. A mathematical model describing the production of single-strand and double-strand breaks in DNA as a function radiation quality has been completed. For the first time Monte Carlo techniques have been used to obtain directly the spatial distribution of DNA moieties altered by radiation. This information was obtained by including the transport codes a realistic description of the electronic structure of DNA. We have investigated structure activity relationships for the potential oncogenicity of a new generation of bioreductive drugs that function as hypoxic cytotoxins. Experimental and theoretical investigation of the inverse dose rate effect, whereby medium LET radiations actually produce an c effect when the dose is protracted, is now at a point where the basic mechanisms are reasonably understood and the complex interplay between dose, dose rate and radiation quality which is necessary for the effect to be present can now be predicted at least in vitro. In terms of early radiobiological damage, a quantitative link has been established between basic energy deposition and locally multiply damaged sites, the radiochemical precursor of DNA double strand breaks; specifically, the spatial and energy deposition requirements necessary to form LMDs have been evaluated. For the first time, a mechanically understood ''biological fingerprint'' of high-LET radiation has been established. Specifically measurement of the ratio of inter-to intra-chromosomal aberrations produces a unique signature from alpha-particles or neutrons

Radiation physics, biophysics, and radiation biology

Energy Technology Data Exchange (ETDEWEB)

Hall, E.J.; Zaider, M.

1993-05-01

Research at the Center for Radiological Research is a multidisciplenary blend of physics, chemistry and biology aimed at understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. The focus is increased on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights of the program from the past year are described. A mathematical model describing the production of single-strand and double-strand breaks in DNA as a function radiation quality has been completed. For the first time Monte Carlo techniques have been used to obtain directly the spatial distribution of DNA moieties altered by radiation. This information was obtained by including the transport codes a realistic description of the electronic structure of DNA. We have investigated structure activity relationships for the potential oncogenicity of a new generation of bioreductive drugs that function as hypoxic cytotoxins. Experimental and theoretical investigation of the inverse dose rate effect, whereby medium LET radiations actually produce an c effect when the dose is protracted, is now at a point where the basic mechanisms are reasonably understood and the complex interplay between dose, dose rate and radiation quality which is necessary for the effect to be present can now be predicted at least in vitro. In terms of early radiobiological damage, a quantitative link has been established between basic energy deposition and locally multiply damaged sites, the radiochemical precursor of DNA double strand breaks; specifically, the spatial and energy deposition requirements necessary to form LMDs have been evaluated. For the first time, a mechanically understood biological fingerprint'' of high-LET radiation has been established. Specifically measurement of the ratio of inter-to intra-chromosomal aberrations produces a unique signature from alpha-particles or neutrons.

Cosmic radiation

Energy Technology Data Exchange (ETDEWEB)

Capdevielle, J N

1984-01-01

First, the different instruments and techniques of cosmic particle detection are presented. Then the passage of the cosmic particles through the atmosphere is studied: electrons, photons, muons. The collective behavior of the different categories is also studied, the electromagnetic cascade is distinguished from the hadron cascade. Through the principal physical properties of the radiation and the medium, the ''mean'' aspects of the radiation are then successively dealt with out of the atmosphere, at different altitudes until the sea level, then at great depths. A chapter is devoted to cosmic radiation of more than 10,000 GeV, studied separately. Then solar radiation in universe is studied through their propagation in solar system and their origin. At last, the cosmic radiation effects are studied in environment (cosmic biophysics) and some applications of cosmic radiation are presented.

Radiation protection - Revision of French radiation protection regulations (1988)

International Nuclear Information System (INIS)

Mayoux, J.C.

1989-01-01

This article analyses the recent amendments to the 1966 and 1975 Decrees on general radiation protection principles and radiation protection of workers in large nuclear installations respectively and also describes national radiation protection law. In particular, the amendments incorporate the revised EURATOM basic radiation protection standards and the new international units (sievert and becquerel replace rem and curie) in the Decrees. (NEA) [fr

Radiation

International Nuclear Information System (INIS)

Winther, J.F.; Ulbak, K.; Dreyer, L.; Pukkala, E.; Oesterlind, A.

1997-01-01

Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

Antiradiation Vaccine: Immunological neutralization of Radiation Toxins at Acute Radiation Syndromes.

Science.gov (United States)

Popov, Dmitri; Maliev, Slava

Introduction: Current medical management of the Acute Radiation Syndromes (ARS) does not include immune prophylaxis based on the Antiradiation Vaccine. Existing principles for the treatment of acute radiation syndromes are based on the replacement and supportive therapy. Haemotopoietic cell transplantation is recomended as an important method of treatment of a Haemopoietic form of the ARS. Though in the different hospitals and institutions, 31 pa-tients with a haemopoietic form have previously undergone transplantation with stem cells, in all cases(100%) the transplantants were rejected. Lethality rate was 87%.(N.Daniak et al. 2005). A large amount of biological substances or antigens isolated from bacterias (flagellin and derivates), plants, different types of venom (honeybees, scorpions, snakes) have been studied. This biological active substances can produce a nonspecific stimulation of immune system of mammals and protect against of mild doses of irradiation. But their radioprotection efficacy against high doses of radiation were not sufficient. Relative radioprotection characteristics or adaptive properties of antioxidants were expressed only at mild doses of radiation. However antioxidants demonstrated a very low protective efficacy at high doses of radiation. Some ex-periments demonstrated even a harmful effect of antioxidants administered to animals that had severe forms of the ARS. Only Specific Radiation Toxins roused a specific antigenic stim-ulation of antibody synthesis. An active immunization by non-toxic doses of radiation toxins includes a complex of radiation toxins that we call the Specific Radiation Determinant (SRD). Immunization must be provided not less than 24 days before irradiation and it is effective up to three years and more. Active immunization by radiation toxins significantly reduces the mortality rate (100%) and improves survival rate up to 60% compare with the 0% sur-vival rate among the irradiated animals in control groups

Radiation enteritis

International Nuclear Information System (INIS)

Ochsner, S.F.; Head, L.H.

1973-01-01

A comprehensive review of radiation enteritis is presented. Experience in clinical radiation therapy has indicated that the small bowel is the segment of the alimentary tract that is most susceptible to radiation damage. (U.S.)

Radiation sickness

Science.gov (United States)

... exposure to ionizing radiation. There are two main types of radiation: nonionizing and ionizing. Nonionizing radiation comes in the form of light, radio waves, microwaves and radar. These forms usually don't cause tissue damage. ...

Calculating the diffuse solar radiation in regions without solar radiation measurements

International Nuclear Information System (INIS)

Li, Huashan; Bu, Xianbiao; Long, Zhen; Zhao, Liang; Ma, Weibin

2012-01-01

Correlations for calculating diffuse solar radiation can be classified into models with global solar radiation (H-based method) and without it (Non-H method). The objective of the present study is to compare the performance of H-based and Non-H methods for calculating the diffuse solar radiation in regions without solar radiation measurements. The comparison is carried out at eight meteorological stations in China focusing on the monthly average daily diffuse solar radiation. Based on statistical error tests, the results show that the Non-H method that includes other readily available meteorological elements gives better estimates. Therefore, it can be concluded that the Non-H method is more appropriate than the H-based one for calculating the diffuse solar radiation in regions without solar radiation measurements. -- Highlights: ► Methods for calculating diffuse solar radiation in regions without solar radiation measurements are investigated. ► Diffuse solar radiation models can be classified into two groups according to global solar radiation. ► Two approaches are compared at the eight meteorological stations in China. ► The method without global solar radiation is recommended.

Radiation monitor

International Nuclear Information System (INIS)

Pao, C.T.; Green, W.K.

1978-01-01

A system for indicating radiation from a radioactive fluid such as a gas wherein simultaneous indications of the activity concentration of radioactivity of the gas, the radiation dose rate and average energy of the radiation are provided

Radiation safety

International Nuclear Information System (INIS)

Auxier, J.A.

1977-01-01

Data available on the biological effects of radiation on man are reviewed, with emphasis on dose response to low LET and high LET radiation sources, and the effects of dose rate. Existing guides for radiation protection were formulated largely on the basis of tumor induction in the bone of radium dial painters, but the ICRP/NCRP annual dose guides of 5 rem/yr are of the same general magnitude as the doses received in several parts of the world from the natural radiation environment. Because of the greater sensitivity of rapidly dividing cells and the assumption that radiation occupations would not begin before the age of eighteen, maximum exposure levels were set as 5 (N-18) rem/yr, where N is the exposed worker's age in years. However, in the case of the natural radiation environment, exposure commences, in a sense, with the exposure of the ovum of the individual's mother; and the ovum is formed during the fetal development of the mother. In occupational exposures, the professional health physicist has always practiced the as low as practical philosophy, and exposures have generally averaged far below the guidelines. The average annual exposure of the radiation worker in modern plants and laboratories is approximately equal to the average natural radiation environment exposure rate and far lower than the natural radiation environment in many parts of the world. There are numerous complications and uncertainties in quantifying radiation effects on humans, however, the greatest is that due to having to extrapolate from high dose levels at which effects have been measured and quantified, to low levels at which most exposures occur but at which no effects have been observed

Radiation imaging

Energy Technology Data Exchange (ETDEWEB)

Redmayne, I.

1986-05-21

A detector for the detection of radiation such as X-ray radiation comprises an array of scintillation elements embedded in a sheet of radiation absorbing material. The scintillation elements are monitored individually, for example by a corresponding array of photodiodes, to build up a picture of the incident radiation. The front face of the sheet and the inner walls of the bores may be coated with a reflective material. The detector finds particular application in weld radiography. The detector may be stepped relative to the radiation source, the signals produced by the rows of the detector as they pass a predetermined point being summed.

Radiation imaging

International Nuclear Information System (INIS)

Redmayne, Ian.

1986-01-01

A detector for the detection of radiation such as X-ray radiation comprises an array of scintillation elements embedded in a sheet of radiation absorbing material. The scintillation elements are monitored individually, for example by a corresponding array of photodiodes, to build up a picture of the incident radiation. The front face of the sheet and the inner walls of the bores may be coated with a reflective material. The detector finds particular application in weld radiography. The detector may be stepped relative to the radiation source, the signals produced by the rows of the detector as they pass a predetermined point being summed. (author)

Radiation carcinogenesis

International Nuclear Information System (INIS)

Adams, G.E.

1987-01-01

In this contribution about carcinogenesis induced by ionizing radiation some radiation dose-response relationships are discussed. Curves are shown of the relation between cell survival and resp. low and high LET radiation. The difference between both curves can be ascribed to endogenous repair mechanisms in the cell. The relation between single-gen mutation frequency and the surviving fractions of irradiated cells indicates that these repairing mechanisms are not error free. Some examples of reverse dose-response relationships are presented in which decreasing values of dose-rate (LET) correspond with increasing radiation induced cell transformation. Finally some molecular aspects of radiation carcinogenesis are discussed. (H.W.). 22 refs.; 4 figs

Ionizing radiations

International Nuclear Information System (INIS)

Newton, W.

1984-01-01

The purpose of this article is to simplify some of the relevant points of legislation, biological effects and protection for the benefit of the occupational health nurse not familiar with the nuclear industries. The subject is dealt with under the following headings; Understanding atoms. What is meant by ionizing radiation. Types of ionizing radiation. Effects of radiation: long and short term somatic effects, genetic effects. Control of radiation: occupational exposure, women of reproductive age, medical aspects, principles of control. The occupational health nurse's role. Emergency arrangements: national arrangements for incidents involving radiation, action to be taken by the nurse. Decontamination procedures: external and internal contamination. (U.K.)

Medical radiation

International Nuclear Information System (INIS)

1992-01-01

This leaflet in the At-a-Glance Series describes the medical use of X-rays, how X-rays help in diagnosis, radiation protection of the patient, staff protection, how radioactive materials in nuclear medicine examinations help in diagnosis and the use of radiation in radiotherapy. Magnetic resonance imaging, a diagnostic technique involving no ionizing radiation, is also briefly examined. The role of the NRPB in the medical use of radiation is outlined. (UK)

Risk Factors: Radiation

Science.gov (United States)

Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation.

Ionizing radiation

International Nuclear Information System (INIS)

Dennis, J.A.

1982-01-01

The subject is discussed under the headings: characteristics of ionizing radiations; biological effects; comparison of radiation and other industrial risks; principles of protection; cost-benefit analysis; dose limits; the control and monitoring of radiation; reference levels; emergency reference levels. (U.K.)

Radiation protection in medical imaging and radiation oncology

CERN Document Server

Stoeva, Magdalena S

2016-01-01

Radiation Protection in Medical Imaging and Radiation Oncology focuses on the professional, operational, and regulatory aspects of radiation protection. Advances in radiation medicine have resulted in new modalities and procedures, some of which have significant potential to cause serious harm. Examples include radiologic procedures that require very long fluoroscopy times, radiolabeled monoclonal antibodies, and intravascular brachytherapy. This book summarizes evidence supporting changes in consensus recommendations, regulations, and health physics practices associated with these recent advances in radiology, nuclear medicine, and radiation oncology. It supports intelligent and practical methods for protection of personnel, the public, and patients. The book is based on current recommendations by the International Commission on Radiological Protection and is complemented by detailed practical sections and professional discussions by the world’s leading medical and health physics professionals. It also ...

Relationship between Metabolic Syndrome and Predictors for Clinical Benign Prostatic Hyperplasia Progression and International Prostate Symptom Score in Patients with Moderate to Severe Lower Urinary Tract Symptoms.

Science.gov (United States)

Zhao, Sicong; Chen, Chao; Chen, Zongping; Xia, Ming; Tang, Jianchun; Shao, Sujun; Yan, Yong

2016-06-28

To investigate the association between metabolic syndrome (MetS) and the predictors of the progression of benign prostatic hyperplasia (BPH) and the corresponding frequency and severity of lower urinary tract symptoms (LUTS). A total of 530 men with moderate to severe International Prostate Symptom Score (IPSS) > 7 were recruited in the present study. The predictors for clinical BPH progression were defined as the total prostate volume (TPV) ≥ 31 cm3, prostate-specific antigen level (PSA) ≥ 1.6 ng/mL, maximal flow rate (Qmax) < 10.6 mL/s, postvoid residual urine volume (PVR) of ≥ 39 mL, and age 62 years or older. LUTS were defined according to the IPSS and MetS with the National Cholesterol Education Program-Adult Treatment Panel III guidelines. The Mantel-Haenszel extension test and the multivariate logistic regression analyses were used to statistically examine their relationships. The percentage of subjects with ≥ 1 predictors for clinical BPH progression, the percentage of subjects with a TPV ≥ 31 cm3, the percentage of subjects with a PVR ≥ 39 mL, and the percentage of subjects with a Qmax < 10.6 mL/s increased significantly with the increasing in the number of MetS components (all P < .05). After adjusting for age and serum testosterone level, the MetS were independently associated with the presence of TPV ≥ 31 cm3 (OR = 17.030, 95% CI: 7.495-38.692). Moreover, MetS was positively associated with the severity of LUTS (P < .001) and voiding scores (P < .001), and each individual MetS component appeared as an independent risk factor for severe LUTS (IPSS > 19, all P < .001). Our data have shown that the MetS significantly associated with the predictors for clinical BPH progression and the frequency and severity of LUTS, especially the voiding symptoms. The prevention of such modifiable factors by promotion of dietary changes and regular physical activity practice may be of great importance for public health. .

Increased serum C-reactive protein level is associated with increased storage lower urinary tract symptoms in men with benign prostatic hyperplasia.

Directory of Open Access Journals (Sweden)

Shun-Fa Hung

Full Text Available OBJECTIVE: Chronic inflammation is considered as one of the contributing mechanisms of lower urinary tract symptoms (LUTS. Serum C-reactive protein (CRP level is the widely used biomarker of inflammatory status. This study investigated the association between serum CRP level in men with benign prostatic hyperplasia (BPH and lower urinary tract symptoms (LUTS before and after medical treatment. METHODS: A total of 853 men with BPH and LUTS were enrolled. All patients completed the International Prostate Symptoms Score (IPSS questionnaire and urological examinations. The parameters of uroflowmetry (maximum flow rate, Qmax; voided volume, VV, post-void residual (PVR, total prostate volume (TPV and transition zone index (TZI, serum prostate specific antigen (PSA, and serum CRP levels were obtained. All patients were treated with alpha-blocker or antimuscarinic agent based on the IPSS voiding to storage subscore ratio (IPSS-V/S. Correlation analyses were performed between serum CRP levels with age, IPSS, TPV, TZI, Qmax, PVR, VV, PSA and between baseline and post treatment. RESULTS: The mean age was 66.9 ± 11.6 years old and the mean serum CRP levels were 0.31 ± 0.43 mg/dL. Univariate analyses revealed serum CRP levels were significantly associated with age (p<0.001, PSA levels (p = 0.005 and VV (p = 0.017, but not significantly associated with TPV (p = 0.854 or PVR (p = 0.068. CRP levels were positively associated with urgency (p<0.001 and nocturia (p<0.001 subscore of IPSS, total IPSS (p = 0.008 and storage IPSS (p<0.001 and negatively associated with IPSS- V/S ratio (p = 0.014. Multivariate analyses revealed that serum CRP levels were significantly associated with age (p = 0.004 and storage IPSS subscore p<0.001. Patients with IPSS-V/S<1 and treated with tolterodine for 3 months had significant decrease of CRP levels after treatment. CONCLUSION: Serum CRP levels are associated with storage LUTS and sensory bladder disorders, suggesting chronic

Factors Influencing Nonabsolute Indications for Surgery in Patients With Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia: Analysis Using Causal Bayesian Networks

Directory of Open Access Journals (Sweden)

Myong Kim

2014-12-01

Full Text Available Purpose To identify the factors affecting the surgical decisions of experienced physicians when treating patients with lower urinary tract symptoms that are suggestive of benign prostatic hyperplasia (LUTS/BPH. Methods Patients with LUTS/BPH treated by two physicians between October 2004 and August 2013 were included in this study. The causal Bayesian network (CBN model was used to analyze factors influencing the surgical decisions of physicians and the actual performance of surgery. The accuracies of the established CBN models were verified using linear regression (LR analysis. Results A total of 1,108 patients with LUTS/BPH were analyzed. The mean age and total prostate volume (TPV were 66.2 (±7.3, standard deviation years and 47.3 (±25.4 mL, respectively. Of the total 1,108 patients, 603 (54.4% were treated by physician A and 505 (45.6% were treated by physician B. Although surgery was recommended to 699 patients (63.1%, 589 (53.2% actually underwent surgery. Our CBN model showed that the TPV (R=0.432, treating physician (R=0.370, bladder outlet obstruction (BOO on urodynamic study (UDS (R=0.324, and International Prostate Symptom Score (IPSS question 3 (intermittency; R=0.141 were the factors directly influencing the surgical decision. The transition zone volume (R=0.396, treating physician (R=0.340, and BOO (R=0.300 directly affected the performance of surgery. Compared to the LR model, the area under the receiver operating characteristic curve of the CBN surgical decision model was slightly compromised (0.803 vs. 0.847, P<0.001, whereas that of the actual performance of surgery model was similar (0.801 vs. 0.820, P=0.063 to the LR model. Conclusions The TPV, treating physician, BOO on UDS, and the IPSS item of intermittency were factors that directly influenced decision-making in physicians treating patients with LUTS/BPH.

Counterbalanced radiation detection system

International Nuclear Information System (INIS)

Platz, W.

1987-01-01

A counterbalanced radiation detection system is described comprising: (a) a stand; (b) a first radiation detector; (c) a first radiation detector arm means for tiltably connecting the first radiation detector with the stand; (d) a second radiation detector; (e) a second radiation detector arm means for tiltably connecting the second radiation detector with the stand, whereby the tilting angles of the radiation detector arm means define a distance between the radiation detectors; and (f) a torque transforming means connected between the first and second radiation detector arm means for transforming the torque created by one of the radiation detectors in a sense opposed to the torque created by the other radiation detector

Precautions against radiations

International Nuclear Information System (INIS)

Osborn, S.B.

1986-01-01

In this chapter the characteristics of ionizing and non-ionizing radiations likely to cause hazards in a chemical laboratory are considered. Quantities and units of radiation are described. The general principles of radiation protection, precautions against radiation hazards, ICRP standards and recommendations and the legislation relating to the control of radiation hazards in the UK are discussed. (U.K.)

Radiation exposure and radiation risk of the population

International Nuclear Information System (INIS)

Jacobi, W.; Paretzke, H.G.; Ehling, U.H.

1981-02-01

The major scientifically founded results concerning the assessment of the radiation exposure and the analysis and evaluation of the radiationhazards for the population, particularly in the range of low doses, are presented. As to the risk analysis special attention is paid to the rays with low ionization density (X-, γ-, β- and electronrays). Contents: 1) Detailed survey of the results and conclusions; 2) Data on the radiation load of the population; 3) Results to epidemiological questioning on the risk of cancer; 4) Genetical radiation hazards of the population. For quantification purposes of the risk of cancer by γ-radiation the observations with the a-bomb survivors in Japan are taken as a basis, as the available dosimetrical data have to be revised. Appendices: 1) German translation of the UNSCEAR-Report (1977); 2) BEIR-Report (1980); 3) Comments from the SSK on the comparability of the risks of natural-artificial radiation exposure; 4) Comments from the SSK on the importance of synergistical influences for the radiation protection (23.9.1977). (HP) [de

Roentgen's heritage and radiation phobia, a challenge to radiation research and radiation protection

International Nuclear Information System (INIS)

Feinendegen, L.E.

1996-01-01

Present practice of applying linearity to assessing risk even from very low dose exposure of complex tissues to ionising radiation has been evaluated in terms of microdosimetric approach to energy deposition in tissues, nature of radiation and also the magnitudes of conditioning and challenging doses. This paper discusses the probability of radiation risk at quite low doses on the tissues in terms of simple mathematical terms. (author). 13 refs., 2 figs., 1 tab

Occupational radiation exposure monitoring among radiation workers in Nepal

International Nuclear Information System (INIS)

Bhatt, Chhavi Raj; Shrestha, Shanta Lall; Khanal, Tara; Ween, Borgny

2008-01-01

Nepal was accepted as a member of the IAEA in 2007. Nepal is one of the world's least developed countries and is defined in Health Level IV. The population counted 26.4 millions in 2007. The health care sector increases with new hospitals and clinics, however, Nepal has no radiation protection authority or radiation protection regulation in the country until now. The radiation producing equipment in the health sector includes conventional X-ray and dental X-ray equipment, fluoroscopes, mammography, CT, catheterization laboratory equipment, nuclear medicine facilities, a few linear accelerators, Co 60 teletherapy and High Dose Rate brachytherapy sources. The situation regarding dosimetry service for radiation workers is unclear. A survey has been carried out to give an overview of the situation. The data collection of the survey was performed by phone call interviews with responsible staff at the different hospitals and clinics. Data about different occupationally exposed staff, use of personal radiation monitoring and type of dosimetry system were collected. In addition, it was asked if dosimetry reports were compiled in files or databases for further follow-up of staff, if needed. The survey shows that less of 25% of the procedures performed on the surveyed hospitals and clinics are performed by staff with personnel radiation monitoring. Radiation monitoring service for exposed staff is not compulsory or standardized, since there is no radiation protection authority. Nepal has taken a step forward regarding radiation protection, with the IAEA membership, although there are still major problems that have to be solved. An evaluation of the existing practice of staff dosimetry can be the first helpful step for further work in building a national radiation protection authority. (author)

Radiation safety

International Nuclear Information System (INIS)

Van Riessen, A.

2002-01-01

Full text: Experience has shown that modem, fully enclosed, XRF and XRD units are generally safe. This experience may lead to complacency and ultimately a lowering of standards which may lead to accidents. Maintaining awareness of radiation safety issues is thus an important role for all radiation safety officers. With the ongoing progress in technology, a greater number of radiation workers are more likely to use a range of instruments/techniques - eg portable XRF, neutron beam analysis, and synchrotron radiation analysis. The source for each of these types of analyses is different and necessitates an understanding of the associated dangers as well as use of specific radiation badges. The trend of 'suitcase science' is resulting in scientists receiving doses from a range of instruments and facilities with no coordinated approach to obtain an integrated dose reading for an individual. This aspect of radiation safety needs urgent attention. Within Australia a divide is springing up between those who work on Commonwealth property and those who work on State property. For example a university staff member may operate irradiating equipment on a University campus and then go to a CSIRO laboratory to operate similar equipment. While at the University State regulations apply and while at CSIRO Commonwealth regulations apply. Does this individual require two badges? Is there a need to obtain two licences? The application of two sets of regulations causes unnecessary confusion and increases the workload of radiation safety officers. Radiation safety officers need to introduce risk management strategies to ensure that both existing and new procedures result in risk minimisation. A component of this strategy includes ongoing education and revising of regulations. AXAA may choose to contribute to both of these activities as a service to its members as well as raising the level of radiation safety for all radiation workers. Copyright (2002) Australian X-ray Analytical

Radiation exposure

International Nuclear Information System (INIS)

Dalton, L.K.

1991-01-01

The book gives accounts of some social and environmental impacts of the developing radiation industries, including the experiences of affected communities and individuals. Its structure is based on a division which has been made between nuclear and non-nuclear radiation sources, because they create distinctly different problems for environmental protection and so for public health policy. The emissions from electronic and electrical installations - the non-nuclear radiations - are dealt with in Part I. Emissions from radioactive substances - the nuclear radiations - are dealt with in Part II. Part III is for readers who want more detailed information about scientific basis of radiation-related biological changes and their associated health effects. 75 refs., 9 tabs., 7 figs., ills

Radiation sickness

International Nuclear Information System (INIS)

Endoh, Masaru; Ishida, Yusei; Saeki, Mitsuaki

1983-01-01

The frequency of radiation sickness in 1,060 patients treated at our Department was 12.8 percent. It was frequent in patients with brain cancer (12 percent), whole spine cancer (47 percent), uterus cancer (28 percent), lung cancer (22 percent) and esophagus cancer (12 percent). Radiation sickness following X-irradiation was studied in its relation to patient's age, size of radiation fields, dosis and white blood cell count. However, we could not find any definite clinical feature relevant to occurrence. There are many theories published concerning the mechanism of radiation sickness. Clinical experiences have shown that radiation sickness cannot be explained by one theory alone but by several theories such as those based on psychology, stress or histamine. (author)

Current perspectives of radiation therapy. History of radiation therapy

International Nuclear Information System (INIS)

Itami, Jun

2011-01-01

More than 100 years have passed since the discovery of X-Strahlen by Roentgen. The history of radiation therapy has evolved under mutual stimulating relationships of the external beam radiation therapy by X-ray tubes and accelerators, and the internal radiation therapy employing radium and other radionuclides. The currently employed technologies in radiation therapy have its origin already till nineteen sixties and the development of physics and engineering have realized the original concept. (author)

Focus radiation protection

International Nuclear Information System (INIS)

Ebermann, Lutz

2016-01-01

The publication of the Bundesamt fuer Strahlenschutz on radiation protection covers the following issues: (i) exposure from natural sources: health hazard due to radon, radiation protection in residential homes, radon in Germany, natural raw materials in industrial processes; (ii) clearance of radioactive wastes: clearance in the frame of nuclear power plant dismantling, the situation in Germany and Europe; (iii) emergency management: principles of radiation protection, fictive sequence of accident events; (iiii) other actual radiation protection topics: more limits - more protection? radiation protection in medicine, occupational radiation protection.

Radiation studied on the internet. On-line radiation teaching materials

International Nuclear Information System (INIS)

Inoue, Hiroyoshi; Kagoshima, Mayumi; Yamasaki, Mariko

2005-01-01

In order to facilitate scientific understanding of radiation in Japan where social understanding has been already progressed, we developed Internet radiation teaching materials that can be utilized as off-school teaching materials or supplementary materials. The teaching materials of ''atomic structure and radiation'' and ''medical treatment and radiation'' were tried for 160 high school students and 59 junior high school students, respectively. More than 70% of the student answered that these teaching materials were effective when they understand radiation. (author)

Radiation induced sarcomas of bone following therapeutic radiation

International Nuclear Information System (INIS)

Kim, J.H.; Chu, F.C.H.; Woodward, H.Q.; Huvos, A.

1983-01-01

Because of new therapeutic trends of multi-modality and the importance of late effects, we have updated our series of radiation induced bone sarcomas seen at Memorial Sloan-Kettering Cancer Center over the past four decades. A total of 37 cases of bone sarcoma arising from normal bone in the irradiated field was analyzed. The median for latent period from irradiation to diagnosis of bone sarcoma was 11 years with a minimum latent period of four years. The median radiation dose for the bone sarcoma was 6000 rad in 6 weeks with a minimum total radiation dose of 3000 rad in 3 weeks. We have found nine patients who developed bone sarcomas in the radiation field after successful treatment of Hodgkin's disease. Criteria for radiation induced bone sarcomas and the magnitude of the risk of bone sarcomas are briefly discussed

Radiation safety audit

International Nuclear Information System (INIS)

Kadadunna, K.P.I.K.; Mod Ali, Noriah

2008-01-01

Audit has been seen as one of the effective methods to ensure harmonization in radiation protection. A radiation safety audit is a formal safety performance examination of existing or future work activities by an independent team. Regular audit will assist the management in its mission to maintain the facilities environment that is inherently safe for its employees. The audits review the adequacy of facilities for the type of use, training, and competency of workers, supervision by authorized users, availability of survey instruments, security of radioactive materials, minimization of personnel exposure to radiation, safety equipment, and the required record keeping. All approved areas of use are included in these periodic audits. Any deficiency found in the audit shall be corrected as soon as possible after they are reported. Radiation safety audit is a proactive approach to improve radiation safety practices and identify and prevent any potential radiation accident. It is an excellent tool to identify potential problem to radiation users and to assure that safety measures to eliminate or reduce the problems are fully considered. Radiation safety audit will help to develop safety culture of the facility. It is intended to be the cornerstone of a safety program designed to aid the facility, staff and management in maintaining a safe environment in which activities are carried out. The initiative of this work is to evaluate the need of having a proper audit as one of the mechanism to manage the safety using ionizing radiation. This study is focused on the need of having a proper radiation safety audit to identify deviations and deficiencies of radiation protection programmes. It will be based on studies conducted on several institutes/radiation facilities in Malaysia in 2006. Steps will then be formulated towards strengthening radiation safety through proper audit. This will result in a better working situation and confidence in the radiation protection community

Radiation therapy

International Nuclear Information System (INIS)

Bader, J.L.; Glatstein, E.

1987-01-01

The radiation oncologist encounters the critically ill immunosuppressed patient in four settings. First, the newly diagnosed cancer patient presents for initial evaluation and treatment, with immunosuppression from the cancer itself, malnutrition, concomitant infectious disease, prior drug or alcohol abuse or other medical problems. Second, the previously treated cancer patient presents with metastatic or recurrent primary cancer causing local symptoms. Immune dysfunction in this setting may be due to prior chemotherapy and/or radiation as well as any of the original factors. Third, the patient previously treated with radiation presents with a life-threatening problem possibly due to complications of prior therapy. In this setting, the radiation oncologist is asked to evaluate the clinical problem and to suggest whether radiation might be causing part or all of the problem and what can be done to treat these sequelae of radiation. Fourth, the patient with a benign diagnosis (not cancer) is seen with a problem potentially emeliorated by radiation (e.g., kidney transplant rejection, preparation for transplant, or intractable rheumatoid arthritis). This chapter reviews these four issues and presents clinical and radiobiologic principles on which recommendations for therapy are based

Climatology of Tibetan Plateau Vortices and connection to upper-level flow in reanalysis data and a high-resolution model simulation

Science.gov (United States)

Curio, Julia; Schiemann, Reinhard; Hodges, Kevin; Turner, Andrew

2017-04-01

The Tibetan Plateau (TP) and surrounding high mountain ranges constitute an important forcing of the atmospheric circulation over Asia due to their height and extent. Therefore, the TP impacts weather and climate in downstream regions of East Asia, especially precipitation. Mesoscale Tibetan Plateau Vortices (TPVs) are known to be one of the major precipitation-bearing systems on the TP. They are mainly present at the 500 hPa level and have a vertical extent of 2-3 km while their horizontal scale is around 500 km. Their average lifetime is 18 hours. There are two types of TPVs: the largest number originating and staying on the TP, while a smaller number is able to move off the plateau to the east. The latter category can cause extreme precipitation events and severe flooding in large parts of eastern and southern China downstream of the TP, e.g. the Yangtze River valley. The first aim of the study is to identify and track TPVs in reanalysis data and to connect the TPV activity to the position and strength of the upper-level subtropical jet stream, and to determine favourable conditions for TPV development and maintenance. We identify and track TPVs using the TRACK algorithm developed by Hodges et al. (1994). Relative vorticity at the 500 hPa level from the ERA-Interim and NCEP-CFSR reanalyses are used as input data. TPVs are retained which originate on the TP and which persist for at least two days, since these are more likely to move off the TP to the East. The second aim is to identify TPVs in a high-resolution, present-day climate model simulation of the MetOffice Unified Model (UPSCALE, HadGEM3 GA3.0) to assess how well the model represents the TPV climatology and variability. We find that the reanalysis data sets and the model show similar results for the statistical measures of TPVs (genesis, track, and lysis density). The TPV genesis region is small and stable at a specific region of the TP throughout the year. The reason for this seems to be the convergence

Radiation monitoring

International Nuclear Information System (INIS)

Larsson, L.Eh.; B'yuli, D.K.; Karmikel, Dzh.Kh.E.

1985-01-01

Recommendations on radiation monitoring of personnel, used medical ionizing radiation source, are given. The necessity to carry out radiation monitoring of situation at medical personnel's positions and personnel dosimetry is marked. It is convenient to subdivide radiation monitoring into 3 types: usual, surgical and special. Usual monitoring is connected with current work; surgical monitoring is carried out to receive information during a concrete operation; special monitoring is used to detect possible deviation from standard conditions of work or when suspecting them

The world of radiation

International Nuclear Information System (INIS)

Song, Myeong Jae

2000-12-01

This book deals with the world of radiation with the first meeting discovery of the rays, meeting between radiation and human body, illusion and truth of radiation and philosophy of management for radiation. These are the titles of the stories ; predictor, unforgettable Hiroshima, nude photo, radiation and radioactivity, living in the radiation, people make radiation, too, mysteries in human body, gene, DNA and cell, when radiation meets human body, the first victim in the atomic accident in Japan. The fact of Chernobyl accident, is radiation in the plutonium fatal? body without brain and a deformed calf, management on radiation in the nuclear power plant, ideal and reality is really radiation dangerous? and the good news.

Diagnostic radiation risks

Energy Technology Data Exchange (ETDEWEB)

Sherwood, T [Addenbrooke' s Hospital, Cambridge (UK)

1980-04-01

A brief discussion on diagnostic radiation risks is given. First some fundamental facts on the concepts and units of radiation measurement are clarified. Medical diagnostic radiation doses are also compared to the radiation doses received annually by man from natural background radiation. The controversy concerning the '10-day rule' in X-raying women of child-bearing age is discussed; it would appear that the risk of malformation in an unborn child due to X-radiation is very much less than the natural level of risk of malformation. The differences in the radiographic techniques and thus the different X-ray doses needed to make adequate X-ray images of different parts of the body are considered. The radiation burden of nuclear medicine investigations compared to X-ray procedures is also discussed. Finally, the problems of using volunteers in radiation research are aired.

Nuclear radiation in warfare

International Nuclear Information System (INIS)

Rotblat, J.

1986-01-01

The subject is covered in chapters, entitled: introduction; digest of nuclear weaponry (characteristics of nuclear weapons; effects of nuclear weapons other than ionizing radiation (fire-ball, fall-out, thermal radiation, blast wave, electromagnetic pulse); the nuclear arms race; war scenarios; biological effects of radiations on man (radiation doses; natural sources of radiation; acute effects of radiation; long-term somatic effects; genetic effects; factors affecting the biological response to radiation; internal exposure; synergistic effects; protection against radiation effects); radiations from nuclear explosions (initial radiation; fall-out; effects of fall-out on animal and plant life; contamination of water and food supplies by fall-out); radiation casualties in a nuclear war; effectiveness of civil defence; other warlike uses of radiation (attacks on civilian nuclear power installations; radiological warfare; terrorist activities); conclusion. (orig./HP) [de

Nuclear radiation in warfare

International Nuclear Information System (INIS)

Rotblat, J.

1981-01-01

The subject is covered in chapters, entitled: introduction; digest of nuclear weaponry (characteristics of nuclear weapons; effects of nuclear weapons other than ionizing radiation (fire-ball, fall-out, thermal radiation, blast wave, electromagnetic pulse); the nuclear arms race; war scenarios); biological effects of radiations on man (radiation doses; natural sources of radiation; acute effects of radiation; long-term somatic effects; genetic effects; factors affecting the biological response to radiation; internal exposure; synergistic effects; protection against radiation effects); radiations from nuclear explosions (initial radiation; fall-out; effects of fall-out on animal and plant life; contamination of water and food supplies by fall-out); radiation casualties in a nuclear war; effectiveness of civil defence; other warlike uses of radiation (attacks on civilian nuclear power installations; radiological warfare; terrorist activities); conclusion. (U.K.)

Communication skills training for radiation therapists: preparing patients for radiation therapy.

Science.gov (United States)

Halkett, Georgia; O'Connor, Moira; Aranda, Sanchia; Jefford, Michael; Merchant, Susan; York, Debra; Miller, Lisa; Schofield, Penelope

2016-12-01

Patients sometimes present for radiation therapy with high levels of anxiety. Communication skills training may assist radiation therapists to conduct more effective consultations with patients prior to treatment planning and treatment commencement. The overall aim of our research is to examine the effectiveness of a preparatory programme 'RT Prepare' delivered by radiation therapists to reduce patient psychological distress. The purpose of this manuscript was to describe the communication skills workshops developed for radiation therapists and evaluate participants' feedback. Radiation therapists were invited to participate in two communication skills workshops run on the same day: (1) Consultation skills in radiation therapy and (2) Eliciting and responding to patients' emotional cues. Evaluation forms were completed. Radiation therapists' consultations with patients were then audio-recorded and evaluated prior to providing a follow-up workshop with participants. Nine full day workshops were held. Sixty radiation therapists participated. Positive feedback was received for both workshops with 88% or more participants agreeing or strongly agreeing with all the statements about the different components of the two workshops. Radiation therapists highlighted participating in role play with an actor, discussing issues; receiving feedback; acquiring new skills and knowledge; watching others role play and practicing with checklist were their favourite aspects of the initial workshop. The follow-up workshops provided radiation therapists with feedback on how they identified and addressed patients' psychological concerns; time spent with patients during consultations and the importance of finding private space for consultations. Communication skills training consisting of preparing patients for radiation therapy and eliciting and responding to emotional cues with follow-up workshops has the potential to improve radiation therapists' interactions with patients undergoing

Living with radiation

International Nuclear Information System (INIS)

Tymen, G.

1999-01-01

This editorial article discusses the various forms of radiation that we live with. In particular, the general public's lack of knowledge on the subject is mentioned and the concentration of the media on radiation accidents and emissions is looked at critically. The various forms of radiation - ionising and non-ionising - are briefly discussed. Natural ionising radiation sources and in particular radon are described and the increasing proportion of doses attributed to cosmic radiation met in high-flying aircraft and radiation doses resulting from medical examination and treatment are discussed. Non-ionising radiation such as electromagnetic fields generated by power lines, mobile telephones and kitchen equipment and their implications on health are also looked at

Wireless radiation sensor

Science.gov (United States)

Lamberti, Vincent E.; Howell, Jr, Layton N.; Mee, David K.; Kress, Reid L.

2016-08-09

Disclosed is a sensor for detecting radiation. The sensor includes a ferromagnetic metal and a radiation sensitive material coupled to the ferromagnetic metal. The radiation sensitive material is operable to change a tensile stress of the ferromagnetic metal upon exposure to radiation. The radiation is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the changes in the tensile stress.

Radiation carcinogenesis

International Nuclear Information System (INIS)

Fry, R.J.M.

1976-01-01

The risk of iatrogenic tumors with radiation therapy is so outweighed by the benefit of cure that estimates of risk have not been considered necessary. However, with the introduction of chemotherapy, combined therapy, and particle radiation therapy, the comparative risks should be examined. In the case of radiation, total dose, fractionation, dose rate, dose distribution, and radiation quality should be considered in the estimation of risk. The biological factors that must be considered include incidence of tumors, latent period, degree of malignancy, and multiplicity of tumors. The risk of radiation induction of tumors is influenced by the genotype, sex, and age of the patient, the tissues that will be exposed, and previous therapy. With chemotherapy the number of cells at risk is usually markedly higher than with radiation therapy. Clearly the problem of the estimation of comparative risks is complex. This paper presents the current views on the comparative risks and the importance of the various factors that influence the estimation of risk

Health effects of radiation and the implications for radiation safety

International Nuclear Information System (INIS)

Gonzalez, A.J.; Anderer, J.

1991-01-01

In this Paper two elements of a multiphase analysis of radiation exposures in the living environment - the human health effects of ionizing radiation and the implications for radiation safety policy and practices - are presented. Part 1 draws together the current state of scientific knowledge and insight about the human health effects of radiation, describing these in terms of known cause-related deterministic effects and of the estimated incidence of stochastic effects as defined by biostatistics and biological models. The 1988 UNSCEAR report provides an authoritative basis for such an examination. Part 2 explores some of the major implications that the state-of-the-art of radiation biology has - or should have - for radiation safety policy and practices. (author)

Concepts of radiation protection

International Nuclear Information System (INIS)

2013-01-01

This seventh chapter presents the concepts and principles of safety and radiation protection, emergency situations; NORM and TENORM; radiation protection care; radiation protection plan; activities of the radiation protection service; practical rules of radiation protection and the radiation symbol

GRAVITATIONAL RADIATION

Directory of Open Access Journals (Sweden)

Metin SALTIK

1996-03-01

Full Text Available According to classical electromagnetic theory, an accelerated charge or system of charges radiates electromagnetic waves. In a radio transmitter antenna charges are accelerated along the antenna and release electromagnetic waves, which is radiated at the velocity of light in the surrounding medium. All of the radio transmitters work on this principle today. In this study an analogy is established between the principles by which accelerated charge systems markes radiation and the accelerated mass system, and the systems cousing gravitational radiation are investigated.

Radiation-induced polymerization and radiation effect on polymers

International Nuclear Information System (INIS)

Seguchi, Tadao

1977-12-01

The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

Radiation treatment and radiation reactions in dermatology. 2. ed.

Energy Technology Data Exchange (ETDEWEB)

Panizzon, Renato G. [Univ. Hospital CHUV, Lausanne (Switzerland). Dept. of Dermatology; Seegenschmiedt, M. Heinrich (ed.) [Strahlenzentrum Hamburg (Germany)

2015-03-01

Explains the use of radiation treatment in the full range of skin cancers and precancerous lesions. Covers physical and radiobiological principles, dose definitions, radiation reactions, and risk assessments. Revised and updated edition that includes new chapters and numerous additional figures. In this book, leading experts in the dermatological and oncological field describe the use of radiation therapy for the treatment of the full range of dermatological malignancies - including basal cell carcinoma, squamous cell carcinoma, cutaneous lymphomas, Kaposi's sarcoma, melanoma, and Merkel cell tumor - as well as those precancerous lesions and non-malignant dermatological disorders which are amenable to radiation therapy. In each case the specific indications for the use of radiotherapy and its application are clearly explained with the aid of numerous high-quality illustrations. In addition, the book provides a concise introduction to physical and radiobiological principles, selection of radiation factors, dose definitions, radiation reactions, and risk assessments. The new edition has been thoroughly revised and updated to reflect advances in practical knowledge and clinical practice. It will be an invaluable source of information on the management of skin tumors and related non-malignant disorders for both dermatologists, oncologists and radiation oncologists.

Promoting safety culture in radiation industry through radiation audit

International Nuclear Information System (INIS)

Noriah, M.A.

2007-01-01

This paper illustrates the Malaysian experience in implementing and promoting effective radiation safety program. Current management practice demands that an organization inculcate culture of safety in preventing radiation hazard. The aforementioned objectives of radiation protection can only be met when it is implemented and evaluated continuously. Commitment from the workforce to treat safety as a priority and the ability to turn a requirement into a practical language is also important to implement radiation safety policy efficiently. Maintaining and improving safety culture is a continuous process. There is a need to establish a program to measure, review and audit health and safety performance against predetermined standards. This program is known as radiation safety audit and is able to reveal where and when action is needed to make improvements to the systems of controls. A structured and proper radiation self-auditing system is seen as the sole requirement to meet the current and future needs in sustainability of radiation safety. As a result safety culture, which has been a vital element on safety in many industries can be improved and promote changes, leading to good safety performance and excellence. (author)

Radiation treatment and radiation reactions in dermatology. 2. ed.

International Nuclear Information System (INIS)

Panizzon, Renato G.

2015-01-01

Explains the use of radiation treatment in the full range of skin cancers and precancerous lesions. Covers physical and radiobiological principles, dose definitions, radiation reactions, and risk assessments. Revised and updated edition that includes new chapters and numerous additional figures. In this book, leading experts in the dermatological and oncological field describe the use of radiation therapy for the treatment of the full range of dermatological malignancies - including basal cell carcinoma, squamous cell carcinoma, cutaneous lymphomas, Kaposi's sarcoma, melanoma, and Merkel cell tumor - as well as those precancerous lesions and non-malignant dermatological disorders which are amenable to radiation therapy. In each case the specific indications for the use of radiotherapy and its application are clearly explained with the aid of numerous high-quality illustrations. In addition, the book provides a concise introduction to physical and radiobiological principles, selection of radiation factors, dose definitions, radiation reactions, and risk assessments. The new edition has been thoroughly revised and updated to reflect advances in practical knowledge and clinical practice. It will be an invaluable source of information on the management of skin tumors and related non-malignant disorders for both dermatologists, oncologists and radiation oncologists.

Sound radiation quantities arising from a resilient circular radiator.

Science.gov (United States)

Aarts, Ronald M; Janssen, Augustus J E M

2009-10-01

Power series expansions in ka are derived for the pressure at the edge of a radiator, the reaction force on the radiator, and the total radiated power arising from a harmonically excited, resilient, flat, circular radiator of radius a in an infinite baffle. The velocity profiles on the radiator are either Stenzel functions (1-(sigma/a)2)n, with sigma the radial coordinate on the radiator, or linear combinations of Zernike functions Pn(2(sigma/a)2-1), with Pn the Legendre polynomial of degree n. Both sets of functions give rise, via King's integral for the pressure, to integrals for the quantities of interest involving the product of two Bessel functions. These integrals have a power series expansion and allow an expression in terms of Bessel functions of the first kind and Struve functions. Consequently, many of the results in [M. Greenspan, J. Acoust. Soc. Am. 65, 608-621 (1979)] are generalized and treated in a unified manner. A foreseen application is for loudspeakers. The relation between the radiated power in the near-field on one hand and in the far field on the other is highlighted.

Background radiation levels and standards for protection from ionizing radiations

International Nuclear Information System (INIS)

Farai, I.

1999-01-01

Apart from the amount of radiation which a worker may receive while he performs his work, he is also exposed to radiation because of the nature of his environment. In other words, all individuals are subject to some irradiation even though they may not work with radioactive substances. This source of radiation exposure is often referred to as background radiation. In most environments, it is low-level and can be grouped into two natural and man-made. Background radiation provides the basis on which allowable exposure limits for workers are drawn

Radiation watchdog

International Nuclear Information System (INIS)

Manning, R.

1984-01-01

Designated by WHO as a Collaborating Centre, the Radiation Emergency Assistance Center/Training Site (REAC/TS) in Oak Ridge, Tennessee provides assistance to all countries of the Americas in radiation accidents including human contamination or overexposure. It also conducts courses in radiation emergency response for health professionals from throughout the world

Radiation oncology

International Nuclear Information System (INIS)

Anon.

1977-01-01

The Radiation Oncology Division has had as its main objectives both to operate an academic training program and to carry out research on radiation therapy of cancer. Since fiscal year 1975, following a directive from ERDA, increased effort has been given to research. The research activities have been complemented by the training program, which has been oriented toward producing radiation oncologists, giving physicians short-term experience in radiation oncology, and teaching medical students about clinical cancer and its radiation therapy. The purpose of the research effort is to improve present modalities of radiation therapy of cancer. As in previous years, the Division has operated as the Radiation Oncology Program of the Department of Radiological Sciences of the University of Puerto Rico School of Medicine. It has provided radiation oncology support to patients at the University Hospital and to academic programs of the University of Puerto Rico Medical Sciences Campus. The patients, in turn, have provided the clinical basis for the educational and research projects of the Division. Funding has been primarily from PRNC (approx. 40%) and from National Cancer Institute grants channeled through the School of Medicine (approx. 60%). Special inter-institutional relationships with the San Juan Veterans Administration Hospital and the Metropolitan Hospital in San Juan have permitted inclusion of patients from these institutions in the Division's research projects. Medical physics and radiotherapy consultations have been provided to the Radiotherapy Department of the VA Hospital

Ionizing radiation sources. Ionizing radiation interaction with matter

International Nuclear Information System (INIS)

Popits, R.

1976-01-01

Fundamentals of nuclear physics are reviewed under the headings: obtaining of X-rays and their properties; modes of radioactive decay of natural or man-made radionuclides; radioactive neutron sources; nuclear fission as basis for devising nuclear reactors and weapons; thermonuclear reactions; cosmic radiation. Basic aspects of ionizing radiation interactions with matter are considered with regard to charged particles, photon radiation, and neutrons. (A.B.)

Ultraviolet radiation, measurements and safety evaluations for radiation protection purposes

International Nuclear Information System (INIS)

Witew, B.; Fischer, P.G.

1983-01-01

In order to evaluate the effects of ultraviolet radiation, one has to study that photobiologically effective radiation which induces a just measurable threshold reaction. For practical radiation protection, one has to determine the permissible duration of exposure at the end of which the threshold reaction is induced. This time limit is derived by means of spectral measurements and determination of radiation intensity. Detrimental photobiological effects can be avoided, and favourable effects optimized, by observing the time limit. Thus these measurements are used to determine the threshold at which the desired effects of ultraviolet radiation will be accompanied by unwanted effects or damage to persons, as for instance in the use of ultraviolet radiation for operating room sterilization, arc welding work, or cosmetic purposes. (orig.) [de

Radiation protection

International Nuclear Information System (INIS)

1989-01-01

A NRPB leaflet in the 'At-a-Glance' series explains in a simple but scientifically accurate way what radiation is, the biological effects and the relative sensitivity of different parts of the human body. The leaflet then discusses radiation protection principles, radiation protection in the UK and finally the effectiveness of this radiation protection as judged by a breakdown of the total dose received by an average person in the UK, a heavy consumer of Cumbrian seafood, an average nuclear industry worker and an average person in Cornwall. (UK)

Synchrotron radiation

International Nuclear Information System (INIS)

Farge, Y.

1982-01-01

Synchrotron radiation is produced by electrons accelerated near the velocity of light in storage rings, which are used for high energy Physics experiments. The radiation light exhibits a wide spread continuous spectrum ranging from 01 nanometre to radiofrequency. This radiation is characterized by high power (several kilowatts) and intense brightness. The paper recalls the emission laws and the distinctive properties of the radiation, and gives some of the numerous applications in research, such as molecular spectroscopy, X ray diffraction by heavy proteins and X ray microlithography in LVSI circuit making [fr

Radiation protection in hospitals

International Nuclear Information System (INIS)

MOuld, R.F.

1985-01-01

A book on radiation protection in hospitals has been written to cater for readers with different backgrounds, training and needs by providing an elementary radiation physics text in Part I and an advanced, comprehensive Part II relating to specific medical applications of X-rays and of radioactivity. Part I includes information on basic radiation physics, radiation risk, radiation absorption and attenuation, radiation measurement, radiation shielding and classification of radiation workers. Part II includes information on radiation protection in external beam radiotherapy, interstitial source radiotherapy, intracavitary radiotherapy, radioactive iodine-131 radiotherapy, nuclear medicine diagnostics and diagnostic radiology. (U.K.)

Preparative radiation chemistry

International Nuclear Information System (INIS)

Drawe, H.

1978-01-01

Preparative synthesis of compounds with the aid of radiation chemistry is increasingly used in laboratories as well as on a technical scale. A large number of new compounds has been produced with the methods of radiation chemistry. With the increasing number of available radiation sources, also the number of synthesis metods in radiation chemistry has increased. This paper can only briefly mention the many possible ways of synthesis in radiation chemistry. (orig./HK) [de

Gravitation radiation observations

OpenAIRE

Glass, E. N.

2017-01-01

The notion of gravitational radiation begins with electromagnetic radiation. In 1887 Heinrich Hertz, working in one room, generated and received electromagnetic radiation. Maxwell's equations describe the electromagnetic field. The quanta of electromagnetic radiation are spin 1 photons. They are fundamental to atomic physics and quantum electrodynamics.

Radiation control system

International Nuclear Information System (INIS)

Murao, Mitsuo.

1985-01-01

Purpose: To rapidly and suitably performing planning and designation by radiation-working control systems in the radiation controlled area of nuclear power plant. Method: Various informations regarding radiation exposure are arranged and actual exposure data are statistically stored, to thereby perform forecasting calculation for the radiation exposure upon workings in the plurality of working regions in the radiation controlled area. Based on the forecast values and the registered workers' exposure dose in the past workings are alocated successively such that the total exposure does upon conducting the workings is less than the limited value, to prepare working plans in the areas. Further, procedures for preparing a series of documents regarding the workings in the radiation area are automated to rapidly and properly provide the informations serving to the planning and designation for the radiation workings. As a result, the radiation managers' burnden can be mitigated and an efficient working management system can be provided, in view of the exposure management and personal management. (Kamimura, M.)

Radiation hazards

International Nuclear Information System (INIS)

Rausch, L.

1979-01-01

On a scientific basis and with the aid of realistic examples, the author gives a popular introduction to an understanding and judgment of the public discussion over radiation hazards: Uses and hazards of X-ray examinations, biological radiation effects, civilisation risks in comparison, origins and explanation of radiation protection regulations. (orig.) [de

Modeling Radiative Heat Transfer and Turbulence-Radiation Interactions in Engines

Energy Technology Data Exchange (ETDEWEB)

Paul, Chandan [Pennsylvania State Univ., University Park, PA (United States); Sircar, Arpan [Pennsylvania State Univ., University Park, PA (United States); Ferreyro-Fernandez, Sebastian [Pennsylvania State Univ., University Park, PA (United States); Imren, Abdurrahman [Pennsylvania State Univ., University Park, PA (United States); Haworth, Daniel C [Pennsylvania State Univ., University Park, PA (United States); Roy, Somesh P [Marquette University (United States); Ge, Wenjun [University of California Merced (United States); Modest, Michael F [University of California Merced (United States)

2017-04-26

Detailed radiation modelling in piston engines has received relatively little attention to date. Recently, it is being revisited in light of current trends towards higher operating pressures and higher levels of exhaust-gas recirculation, both of which enhance molecular gas radiation. Advanced high-efficiency engines also are expected to function closer to the limits of stable operation, where even small perturbations to the energy balance can have a large influence on system behavior. Here several different spectral radiation property models and radiative transfer equation (RTE) solvers have been implemented in an OpenFOAM-based engine CFD code, and simulations have been performed for a full-load (peak pressure ~200 bar) heavy-duty diesel engine. Differences in computed temperature fields, NO and soot levels, and wall heat transfer rates are shown for different combinations of spectral models and RTE solvers. The relative importance of molecular gas radiation versus soot radiation is examined. And the influence of turbulence-radiation interactions is determined by comparing results obtained using local mean values of composition and temperature to compute radiative emission and absorption with those obtained using a particle-based transported probability density function method.

American Society for Radiation Oncology (ASTRO) Survey of Radiation Biology Educators in U.S. and Canadian Radiation Oncology Residency Programs

International Nuclear Information System (INIS)

Rosenstein, Barry S.; Held, Kathryn D.; Rockwell, Sara; Williams, Jacqueline P.; Zeman, Elaine M.

2009-01-01

Purpose: To obtain, in a survey-based study, detailed information on the faculty currently responsible for teaching radiation biology courses to radiation oncology residents in the United States and Canada. Methods and Materials: In March-December 2007 a survey questionnaire was sent to faculty having primary responsibility for teaching radiation biology to residents in 93 radiation oncology residency programs in the United States and Canada. Results: The responses to this survey document the aging of the faculty who have primary responsibility for teaching radiation biology to radiation oncology residents. The survey found a dramatic decline with time in the percentage of educators whose graduate training was in radiation biology. A significant number of the educators responsible for teaching radiation biology were not fully acquainted with the radiation sciences, either through training or practical application. In addition, many were unfamiliar with some of the organizations setting policies and requirements for resident education. Freely available tools, such as the American Society for Radiation Oncology (ASTRO) Radiation and Cancer Biology Practice Examination and Study Guides, were widely used by residents and educators. Consolidation of resident courses or use of a national radiation biology review course was viewed as unlikely by most programs. Conclusions: A high priority should be given to the development of comprehensive teaching tools to assist those individuals who have responsibility for teaching radiation biology courses but who do not have an extensive background in critical areas of radiobiology related to radiation oncology. These findings also suggest a need for new graduate programs in radiobiology.

Thyroid and radiation

Energy Technology Data Exchange (ETDEWEB)

Yamashita, Shunichi; Namba, Hiroyuki; Nagataki, Shigenobu (Nagasaki Univ. (Japan). School of Medicine)

1993-11-01

The topic 'Thyroid and Radiation' is both an old and new area to be solved by human beings. The thyroid is an organ that is usually susceptible to exposure to ionizing radiation, both by virtue of its ability to concentrate radioiodine (internal radiation) and by routine medical examination: Chest X-ray, Dental X-ray, X-irradiation of cervical lymph nodes etc. (external radiation). Iodine-131 is widely used for the therapy of Graves' disease and thyroid cancers, of which the disadvantage is radiation-induced hypothyroidism but not complications of thyroid tumor. The thyroid gland is comparatively radioresistant, however, the data obtained from Hiroshima, Nagasaki and Marshall islands indicates a high incidence of external radiation-induced thyroid tumors as well as hypothyroidism. The different biological effects of internal and external radiation remains to be further clarified. Interestingly, recent reports demonstrate the increased number of thyroid cancer in children around Chernobyl in Belarus. In this review, we would like to introduce the effect of radiation on the thyroid gland at the molecular, cellular and tissue levels. Furthermore the clinical usefulness of iodine-131, including the safety-control for radiation exposure will be discussed. (author) 50 refs.

Basic radiation oncology

International Nuclear Information System (INIS)

Beyzadeoglu, M. M.; Ebruli, C.

2008-01-01

Basic Radiation Oncology is an all-in-one book. It is an up-to-date bedside oriented book integrating the radiation physics, radiobiology and clinical radiation oncology. It includes the essentials of all aspects of radiation oncology with more than 300 practical illustrations, black and white and color figures. The layout and presentation is very practical and enriched with many pearl boxes. Key studies particularly randomized ones are also included at the end of each clinical chapter. Basic knowledge of all high-tech radiation teletherapy units such as tomotherapy, cyberknife, and proton therapy are also given. The first 2 sections review concepts that are crucial in radiation physics and radiobiology. The remaining 11 chapters describe treatment regimens for main cancer sites and tumor types. Basic Radiation Oncology will greatly help meeting the needs for a practical and bedside oriented oncology book for residents, fellows, and clinicians of Radiation, Medical and Surgical Oncology as well as medical students, physicians and medical physicists interested in Clinical Oncology. English Edition of the book Temel Radyasyon Onkolojisi is being published by Springer Heidelberg this year with updated 2009 AJCC Staging as Basic Radiation Oncology

Radiation protection forum

International Nuclear Information System (INIS)

Cabral, W.

2010-01-01

The National Director of the Nuclear Regulatory Authority and Radiation Protection of Uruguay in the first forum for radiation protection set out the following themes: activity of regulatory body, radiation safety, physical security, safeguards, legal framework, committed substantive program, use of radiation, risks and benefits, major sources of radiation, the national regulatory framework, national inventory of sources, inspections, licensing, import and export of sources control , radioactive transport, materials safety, agreements, information and teaching, radiological emergencies and prompt response.

Toxic properties of specific radiation determinant molecules, derived from radiated species

Science.gov (United States)

Popov, Dmitri; Maliev, Vecheslav; Kedar, Prasad; Casey, Rachael; Jones, Jeffrey

Introduction: High doses of radiation induce the formation of radiation toxins in the organs of irradiated mammals. After whole body irradiation, cellular macromolecules and cell walls are damaged as a result of long-lived radiation-induced free radicals, reactive oxygen species, and fast, charged particles of radiation. High doses of radiation induce breaks in the chemical bonds of macromolecules and cross-linking reactions via chemically active processes. These processes result in the creation of novel modified macromolecules that possess specific toxic and antigenic properties defined by the type and dose of irradiation by which they are generated. Radiation toxins isolated from the lymph of irradiated animals are classified as hematotoxic, neurotoxic, and enteric non-bacterial (GI) radiation toxins, and they play an important role in the development of hematopoietic, cerebrovascular, and gastrointestinal acute radiation syndromes (ARS). Seven distinct toxins derived from post-irradiated animals have been designated as Specific Radiation Determinants (SRD): SRD-1 (neurotoxic radiation toxin generated by the cerebrovascular form of ARS), SRD-3 (enteric non-bacterial radiation toxins generated by the gastrointestinal form of ARS), and SRD-4 (hematotoxic radiation toxins generated by the hematological, bone marrow form of ARS). SRD-4 is further subdivided into four groups depending on the severity of the ARS induced: SRD-4/1, mild ARS; SRD-4/2, moderate ARS; SRD-4/3, severe ARS; and SRD-4/4, extremely severe ARS. The seventh SRD, SRD-2 is a toxic extract derived from animals suffering from a fourth form of ARS, as described in European literature and produces toxicity primarily in the autonimic nervous system. These radiation toxins have been shown to be responsible for the induction of important pathophysiological, immunological, and biochemical reactions in ARS. Materials and Methods: These studies incorporated the use of statistically significant numbers of a

Cerebrovascular Acute Radiation Syndrome : Radiation Neurotoxins, Mechanisms of Toxicity, Neuroimmune Interactions.

Science.gov (United States)

Popov, Dmitri; Maliev, Slava

Introduction: Cerebrovascular Acute Radiation Syndrome (CvARS) is an extremely severe in-jury of Central Nervous System (CNS) and Peripheral Nervous System (PNS). CvARS can be induced by the high doses of neutron, heavy ions, or gamma radiation. The Syndrome clinical picture depends on a type, timing, and the doses of radiation. Four grades of the CvARS were defined: mild, moderate, severe, and extremely severe. Also, four stages of CvARS were developed: prodromal, latent, manifest, outcome -death. Duration of stages depends on the types, doses, and time of radiation. The CvARS clinical symptoms are: respiratory distress, hypotension, cerebral edema, severe disorder of cerebral blood microcirculation, and acute motor weakness. The radiation toxins, Cerebro-Vascular Radiation Neurotoxins (SvARSn), determine development of the acute radiation syndrome. Mechanism of action of the toxins: Though pathogenesis of radiation injury of CNS remains unknown, our concept describes the Cv ARS as a result of Neurotoxicity and Excitotoxicity, cell death through apoptotic necrosis. Neurotoxicity occurs after the high doses radiation exposure, formation of radiation neuro-toxins, possible bioradicals, or group of specific enzymes. Intracerebral hemorrhage can be a consequence of the damage of endothelial cells caused by radiation and the radiation tox-ins. Disruption of blood-brain barrier (BBB)and blood-cerebrospinal fluid barrier (BCFB)is possibly the most significant effect of microcirculation disorder and metabolic insufficiency. NMDA-receptors excitotoxic injury mediated by cerebral ischemia and cerebral hypoxia. Dam-age of the pyramidal cells in layers 3 and 5 and Purkinje cell layer the cerebral cortex , damage of pyramidal cells in the hippocampus occur as a result of cerebral ischemia and intracerebral bleeding. Methods: Radiation Toxins of CV ARS are defined as glycoproteins with the molec-ular weight of RT toxins ranges from 200-250 kDa and with high enzymatic activity

Radiation protection problems with sealed Pu radiation sources

International Nuclear Information System (INIS)

Naumann, M.; Wels, C.

1982-01-01

A brief outline of the production methods and most important properties of Pu-238 and Pu-239 is given, followed by an overview of possibilities for utilizing the different types of radiation emitted, a description of problems involved in the safe handling of Pu radiation sources, and an assessment of the design principles for Pu-containing alpha, photon, neutron and energy sources from the radiation protection point of view. (author)

Radiation monitoring system

International Nuclear Information System (INIS)

Takeuchi, Nobuyoshi; Fujimoto, Toshiaki; Nagama, Hideyo

2007-01-01

A positive outlook toward nuclear power plants and a higher level of technologies for using radiation in the medical field are trends that are spreading throughout the world, and as a consequence, demand is increasing for equipment and systems that measure and control radiation. Equipment ranging from radiation detection and measurement devices to computer-based radiation management systems will be set up in overseas. Products that depend on overseas specifications based on IEC and other international standards are being developed. Fuji Electric is advancing the overseas deployment of radiation monitoring systems by adopting measures that will ensure the reliability and traceability of radiation equipment. (author)

Nuclear energy - Radioprotection - Procedure for radiation protection monitoring in nuclear installations for external exposure to weakly penetrating radiation, especially to beta radiation

International Nuclear Information System (INIS)

2002-01-01

This International Standard specifies a procedure for radiation protection monitoring in nuclear installations for external exposure to weakly penetrating radiation, especially to beta radiation and describes the procedure in radiation protection monitoring for external exposure to weakly penetrating radiation in nuclear installations. This radiation comprises β - radiation, β + radiation and conversion electron radiation as well as photon radiation with energies below 15 keV. This International Standard describes the procedure in radiation protection planning and monitoring as well as the measurement and analysis to be applied. It applies to regular nuclear power plant operation including maintenance, waste handling and decommissioning. The recommendations of this International Standard may also be transferred to other nuclear fields including reprocessing, if the area-specific issues are considered. This International Standard may also be applied to radiation protection at accelerator facilities and in nuclear medicine, biology and research facilities

Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

Energy Technology Data Exchange (ETDEWEB)

Scott Wilde, Raymond Keegan

2008-07-01

The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

Perspective of radiation processing

International Nuclear Information System (INIS)

Zhang Manwei

1987-01-01

The area of the applications of radiation techniques is very wide. This paper only relates to the applications of radiation techniques in industries including radiation chemical industry, radiation processing of foods and environmental protection by radiation, but the nuclear instruments and the instrumentations of radiation are out-side of our study. (author)

Radiation chemical transformations of some polyarylates by γ-radiation in vacuum

International Nuclear Information System (INIS)

Lyashevich, V.V.; Korshak, V.V.; Rodeh, V.V.; Timofeeva, G.I.

1976-01-01

A study was made of ageing by radiation of F-2 and D-9 polyarylates using γ-radiation in vacuum. Their high resistance to radiation was indicated. It was found that γ-radiation on polymers caused competing reactions to take place resulting in macromolecular breakdown and structure formation, which in the end produced threedimensional network formation. The initial formation of gel fractions was preceded by the formation of branched macromolecules. The radiation resistance of polyarylates depends on the type of lateral substituent at the central carbon atom of the initial bis-phenol and increases in the presence of a fluorene ring in the lateral chain. The radiation resistance of a lactone ring is lower than that of an ether bond of the main chain. It was shown that 0-hydroxy-ketone structures were formed in the polyarylates examined as a result of regrouping due to radiation. A basic system is proposed for chemical conversion of polyarylates by radiation

Introduction to radiation biology

International Nuclear Information System (INIS)

Uma Devi, P.; Satish Rao, B.S.; Nagarathnam, A.

2000-01-01

This book is arranged in a logical sequence, starting from radiation physics and radiation chemistry, followed by molecular, subcellular and cellular effects and going on to the level of organism. Topics covered include applied radiobiology like modifiers of radiosensitivity, predictive assay, health physics, human genetics and radiopharmaceuticals. The topics covered are : 1. Radiation Physics, 2. Detection and Measurement of Radiation, 3. Radiation Chemistry, 4. DNA Damage and Repair, 5. Chromosomal Aberrations and Gene Mutations, 6. Cellular Radiobiology 7. Acute Radiation Effects, 8. Delayed Effects of Radiation, 9. Biological Basis of Radiotherapy, 10. Chemical Modifiers of Radiosensitivity, 11. Hyperthermia, 12. High LET Radiations in Cancer, Therapy, 13. Predictive Assays, 14. Radiation Effects on Embryos, 15. Human Radiation Genetics, 16. Radiolabelled Compounds in Biology and Medicine and 17. Radiological Health

Radiation. Protection. Health. Proceedings

International Nuclear Information System (INIS)

Hajek, Michael; Maringer, Franz Josef; Steurer, Andreas; Schwaiger, Martina; Timal, Guenter

2015-01-01

The topics of the meeting are the diagnostic and therapeutic application of ionizing radiations, the application of radiation in research, industry and engineering and radiation protection. The volume includes the following chapters: Radiation protection and society, radiation protection infrastructure, population and environment, metrology and measuring techniques, 1. Workshop on population and environment, NORM and radon, 2. Update: dose - extent of damage - limiting value definition, radiation protection for personnel (except medicine), radiation protection in medicine.

Radiation and health

International Nuclear Information System (INIS)

Mohd Yusof Mohd Ali; Noriah Jamal

1996-01-01

Radiation consists of ionizing radiation (IR) and non-ionizing radiation (NIR). Apart from naturally occuring sources, these types of radiation are widely used in Malaysia and can easily be found in Malaysia environment. IR is widely used in industry, medicine and research; while NIR is widely used in industry, medicine, telecommunication, defence, entertainment and research. Recent studies indicate that these radiations are potentially harmful to human beings, in particular the chronic late effects. Based on this understanding, in 1986 (beginning IRPA RM5) Nuclear Energy Unit (NEU) had initiated a number of research projects which primary aims are to gather baseline informations and later to make assessments on the health impact of workers and the population. The projects started off by looking at problems associated with ionizing radiation and these were extended in late 1993, to include non-ionizing radiation

Radiation and health

Energy Technology Data Exchange (ETDEWEB)

Mohd Ali, Mohd Yusof; Jamal, Noriah [Malaysian Inst. for Nuclear Technology Research (MINT), Bangi, Selangor (Malaysia)

1997-12-31

Radiation consists of ionizing radiation (IR) and non-ionizing radiation (NIR). Apart from naturally occuring sources, these types of radiation are widely used in Malaysia and can easily be found in Malaysia environment. IR is widely used in industry, medicine and research; while NIR is widely used in industry, medicine, telecommunication, defence, entertainment and research. Recent studies indicate that these radiations are potentially harmful to human beings, in particular the chronic late effects. Based on this understanding, in 1986 (beginning IRPA RM5) Nuclear Energy Unit (NEU) had initiated a number of research projects which primary aims are to gather baseline informations and later to make assessments on the health impact of workers and the population. The projects started off by looking at problems associated with ionizing radiation and these were extended in late 1993, to include non-ionizing radiation.

Radiation-activated sensor

International Nuclear Information System (INIS)

Nirschl, J.C.

1976-01-01

A sensing system is described for use in a remote location which detects electromagnetic radiation energy, the system being self-activating, turning itself automatically on and off, as a function of radiation intensity across the detector. In essence, when no radiation is present across the detector, the system will consume no power, the switches and MOSFET discriminator being essentially in an ''off'' position. Radiation across the detector provides a current to an input capacitance which when charged turns on the switch and the MOSFET discriminator. A switch driver produces an output pulse showing the presence of radiation; the system then shuts off awaiting the next radiation input. Since the sensor system uses virtually no power unless radiation is present, it is ideally suited for use in remote environments where battery power and size is a predominant consideration. 2 claims, 3 drawing figures

Radiation and Homeostasis

International Nuclear Information System (INIS)

Sugahara, T.; Nikaido, O.; Niwa, O.

2002-01-01

These proceedings aim to promote the understanding of the health hazard of radiation at low dose range and to construct a more solid basis for radiation safety policy. Radiation hazard has been the central issue of investigation in the field of radiation research. The two major approaches are mechanistic analysis by laboratory investigation and phenomenological analysis of radiation-exposed population as represented by epidemiology. In an increasingly safety-conscious society, the extremely low level risk associated with low dose of radiation has become an important issue. In this area, the phenomenological approach has a limit. DNA damage is the primary and direct cause of the risk. Tremendous progress has been made recently in the basic understanding of radiation effects on cells and tissues and the importance of damage response rather than damage itself. This challenges the classical linear non-threshold hypothesis

Radiation shielding plate

International Nuclear Information System (INIS)

Kobayashi, Torakichi; Sugawara, Takeo.

1983-01-01

Purpose: To reduce the weight and stabilize the configuration of a radiation shielding plate which is used in close contact with an object to be irradiated with radiation rays. Constitution: The radiation shielding plate comprises a substrate made of lead glass and a metallic lead coating on the surface of the substrate by means of plating, vapor deposition or the like. Apertures for permeating radiation rays are formed to the radiation shielding plate. Since the shielding plate is based on a lead glass plate, a sufficient mechanical strength can be obtained with a thinner structure as compared with the conventional plate made of metallic lead. Accordingly, if the shielding plate is disposed on a soft object to be irradiated with radiation rays, the object and the plate itself less deform to obtain a radiation irradiation pattern with distinct edges. (Moriyama, K.)

Foundations of radiation physics and radiation protection. 5. ed.; Grundlagen der Strahlungsphysik und des Strahlenschutzes

Energy Technology Data Exchange (ETDEWEB)

Krieger, Hanno

2017-07-01

The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

International Nuclear Information System (INIS)

Cossairt, J.D.

1996-10-01

In the first chapter, terminology, physical and radiological quantities, and units of measurement used to describe the properties of accelerator radiation fields are reviewed. The general considerations of primary radiation fields pertinent to accelerators are discussed. The primary radiation fields produced by electron beams are described qualitatively and quantitatively. In the same manner the primary radiation fields produced by proton and ion beams are described. Subsequent chapters describe: shielding of electrons and photons at accelerators; shielding of proton and ion accelerators; low energy prompt radiation phenomena; induced radioactivity at accelerators; topics in radiation protection instrumentation at accelerators; and accelerator radiation protection program elements

The new radiation protection ordinance and its consequences in radiation therapy

International Nuclear Information System (INIS)

Wucherer, M.; Schmidt, T.

2002-01-01

The new radiation protection ordinance (StrlSchV) entails a number of additional or changed instructions. They require that personnel exposed to radiation at work be reclassified, or that personnel not exposed to radiation at work be classified as personnel exposed to radiation at work, that local dosage measurements be taken particularly in radiation therapy, in order to insure that the radiation protection areas prevailing to date can be maintained, that generally accessible areas be examined to determine whether with persons not exposed to radiation in the course of work, in the case of their prolonged presence there, 1 mSv per year is not exceeded, that instructions be put in writing, that at regular 5-year intervals the proficiency of physicians, specialists in medical physics and MTRAs be brought up to date and, that medical positions for radiooncologists be established. The stricter requirements in radiation protection are inevitably connected with greater expenditures and higher costs. These results of the new radiation protection ordinance are in direct opposition to the financial possibilities that are being restricted through budgeting and pressure on hospitals and practices to reduce costs. (orig.) [de

Physics of radiation

International Nuclear Information System (INIS)

Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

2004-01-01

This chapter discusses the following topics: concept of atom and elements; molecules and compounds; basic principles of radiation; types of radiations; radioactivity, unit of radioactivity, specific activity, radioactive decay, ionisation and ions, interaction of radiation with matters, modes of interaction: photoelectric absorption: Compton scattering, pair-production; attenuation of x and gamma radiation; build-up factors

Counterbalanced radiation detection device

International Nuclear Information System (INIS)

Platz, W.

1986-01-01

A counterbalanced radiation detection device is described which consists of: (a) a base; (b) a radiation detector having a known weight; (c) means connected with the radiation detector and the base for positioning the radiation detector in different heights with respect to the base; (d) electronic component means movably mounted on the base for counterbalancing the weight of the radiation detector; (e) means connected with the electronic component means and the radiation detector positioning means for positioning the electronic component means in different heights with respect to the base opposite to the heights of the radiation detector; (f) means connected with the radiation detector and the base for shifting the radiation detector horizontally with respect to the base; and (g) means connected with the electronic component means and the radiation detector shifting means for shifting the electronic component means horizontally with respect to the base in opposite direction to shifting of the radiation detector

Application of maximum radiation exposure values and monitoring of radiation exposure

International Nuclear Information System (INIS)

1993-01-01

According to the Section 32 of the Radiation Act (592/91) the Finnish Centre for Radiation and Nuclear Safety gives instructions concerning the monitoring of the radiation exposure and the application of the dose limits in Finland. The principles to be applied to calculating the equivalent and the effective doses are presented in the guide. Also the detailed instructions on the application of the maximum exposure values for the radiation work and for the natural radiation as well as the instructions on the monitoring of the exposures are given. Quantities and units for assessing radiation exposure are presented in the appendix of the guide

Information from the National Institute of Radiation Protection about radiation doses and radiation risks at x-ray screening

International Nuclear Information System (INIS)

1975-05-01

This report gives a specification of data concerning radiation doses and risks at x-ray investigations of lungs. The dose estimations are principally based on measurements performed in 1974 by the National Institute of Radiation Protection. The radiation doses at x-ray screening are of that magnitude that the risk for acute radiation injuries is non-existent. At these low doses it has not either been able to prove that the radiation gives long-range effects as changes in the genes or cancer of late appearance. At considerable higher doses, more than tens of thousands of millirads, a risk of cancer appearance at a small part of all irradiated persons has been proved, based on the assumption that the cancer risk is proportional to the radiation dose. Cancer can thus occure at low radiation doses too. Because of the mass radiography in Sweden 1974 about twenty cases of cancer may appear in the future. (M.S.)

Areas of research in radiation chemistry fundamental to radiation biology

International Nuclear Information System (INIS)

Powers, E.L.

1980-01-01

Among all the environmental hazards to which man is exposed, ionizing radiation is the most thoroughly investigated and the most responsibly monitored and controlled. Nevertheless, because of the importance of radiation in modern society from both the hazard as well as the utilitarian standpoints, much more information concerning the biological effects induced and their modification and reversal is required. Together with radiation physics, an understanding of radiation chemistry is necessary for full appreciation of biological effects of high and low energy radiations, and for the development of prophylactic, therapeutic and potentiating methods and techniques in biological organisms. The necessity of understanding the chemistry of any system, biological or not, that is to be manipulated and controlled, is so obvious as to make trivial a statement to that effect. If any natural phenomenon is to be put to our use, surely the elements of it must be studied and appreciated fully. In the preliminary statements of the various panels of this general group, the need for additional information on the basic radiation chemistry concerned in radiation-induced biological effects pervades throughout

Biological radiation effects

International Nuclear Information System (INIS)

Koggl, D.; Dedenkov, A.N.

1986-01-01

All nowadays problems of radio biology are considered: types of ionizing radiations, their interaction with material; damage of molecular structures and their reparation; reaction of cells and their recovery from radiation damage; reaction of the whole organism and its separate systems. Particular attention is given to the problems of radiation carcinogenesis and radiation hazard for man

Pregnancy and Radiation

Directory of Open Access Journals (Sweden)

Hatice Bilge

2010-10-01

Full Text Available Many women per year expose ionizing radiation during pregnancy for medical reason (diagnostic or treatment. Ionizing radiation is known to cause harm on the human embryo and fetus. Potential adverse outcomes related to radiation exposure during pregnancy include teratogenicity, genetic damage, intrauterine death and increased risk of malignancy. Most diagnostic radiation procedures will lead to a fetal absorbed dose of less than 1 mGy (0.1 rad for imaging not involving abdomen / pelvis, less than 50 mGy (5 rad for involving abdomen / pelvis and less than 10 mGy (1 rad for direct or nuclear medicine imaging. When a pregnant patient requires radiation therapy, the physician should consider fetal sensitivity to radiation in early gestational age and the expected dose of radiation and should then calculate the risk to the fetus versus the benefits to the mother. It is safest to administer radiotherapy during or after the 25th week of gestation. The use of radiation for diagnostic imaging or treatment in the pregnant woman is associated with a high level of anxiety for woman, her family and her doctors. This article reviews the biological effects of radiation on the fetus. Recommendations to take in to account when considering the safety of the fetus during a procedure are presented.

Radiation protection textbook

International Nuclear Information System (INIS)

Gambini, D.J.; Granier, R.

2007-01-01

This textbook of radiation protection presents the scientific bases, legal and statutory measures and technical means of implementation of the radioprotection in the medical and industrial sectors, research and nuclear installations. It collects the practical information (organization, analysis of post, prevention, evaluation and risks management, the controls, the training and the information) usually scattered and the theoretical knowledge allowing every person using ionizing radiation: To analyze jobs in controlled areas, to watch the respect for the current regulations, to participate in the training and in the information of the staffs exposed to intervene in accidental situation. This third edition is widely updated and enriched by the most recent scientific and legal data concerning, notably, the human exposure, the dosimetry, the optimization of the radiation protection and the epidemiological inquiries. The contents is as follows: physics of ionizing radiation, ionizing radiation: origin and interaction with matter, dosimetry and protection against ionizing radiation, detection and measurement of ionizing radiation, radiobiology, legal measures relative to radiation protection, human exposure of natural origin, human exposure of artificial origin, medical, dental and veterinarian radiology, radiotherapy, utilization of unsealed sources in medicine and research, electronuclear industry, non nuclear industrial and aeronautical activities exposing to ionizing radiation, accidental exposures. (N.C.)

Radiation protection standards: a summary of the biological effects of ionising radiation and principles of radiation protection

International Nuclear Information System (INIS)

1994-01-01

This leaflet in the NRPB At-a-Glance-Series briefly summarises the biological effects of radiation, harm and sensitivity to radiation, radiation protection principles, acceptability of risk and the control of doses to workers, the public and in medical procedures in the UK. (UK)

Research on radiation effect and radiation protection at JAEA

International Nuclear Information System (INIS)

Saito, Kimiaki

2007-01-01

Researches on radiation effect and radiation protection at JAEA have been carried out in different sections. In recent years, the organizations were rearranged to attain better research circumstances, and new research programs started. At present, radiation effect studies focus on radiation effect mechanisms at atomic, molecular and cellular levels including simulation studies, and protection studies focus on dosimetry for conditions difficult to cover with currently used methods and data as well as the related basic studies. The outlines of the whole studies and also some descriptions on selected subjects will be given in this paper. (author)

Radiation and detectors introduction to the physics of radiation and detection devices

CERN Document Server

Cerrito, Lucio

2017-01-01

This textbook provides an introduction to radiation, the principles of interaction between radiation and matter, and the exploitation of those principles in the design of modern radiation detectors. Both radiation and detectors are given equal attention and their interplay is carefully laid out with few assumptions made about the prior knowledge of the student. Part I is dedicated to radiation, broadly interpreted in terms of energy and type, starting with an overview of particles and forces, an extended review of common natural and man-made sources of radiation, and an introduction to particle accelerators. Particular attention is paid to real life examples, which place the types of radiation and their energy in context. Dosimetry is presented from a modern, user-led point of view, and relativistic kinematics is introduced to give the basic knowledge needed to handle the more formal aspects of radiation dynamics and interaction. The explanation of the physics principles of interaction between radiation an...

Difference in Understanding of the Need for Using Radiation in Various Fields between Students Majoring in Radiation and Non-Radiation Related Studies

Energy Technology Data Exchange (ETDEWEB)

Han, Eun Ok [Dept. of Radiological Tecknology, Daegu Health College, Daegu (Korea, Republic of)

2011-12-15

As a way of improving social receptivity of using radiation, this study looked into the difference of understanding the need of using radiation in various fields between students majoring in radiation and non-radiation related studies, who will influence public opinion in the long term. This study also provides data needed for developing efficient strategies for projects promoting the public's awareness of using radiation. Of the students in the 79 schools sampled, 24%(177) were in 4 year colleges and 146 were junior colleges in educational statistics service (http://cesi.kedi.re.kr) In November 2010 1,945 students were selected as a sample, and they were given surveys on the need of using radiation in different fields. As a result, both between students majoring in radiation and non-radiation related studies showed a high level of understanding the need for radiation in the medical field and showed a low level of understanding of the need for radiation in the agricultural field. In all 6 fields of radiation use, students majoring in radiation related studies showed higher levels of understanding for the need to use radiation than students majoring in radiation and non-radiation related studies. In each field, male students and those who have experience medical radiation and relevant education had higher level of understanding. This shows we need to improve the understanding of the cases of female students and those who have not had experiences with medical radiation and to provide relevant education through various kinds of information. The characteristics of the groups that are shown in the results of this study are considered to be helpful for efficiently for project promoting the public's awareness of using radiation.

Difference in Understanding of the Need for Using Radiation in Various Fields between Students Majoring in Radiation and Non-Radiation Related Studies

International Nuclear Information System (INIS)

Han, Eun Ok

2011-01-01

As a way of improving social receptivity of using radiation, this study looked into the difference of understanding the need of using radiation in various fields between students majoring in radiation and non-radiation related studies, who will influence public opinion in the long term. This study also provides data needed for developing efficient strategies for projects promoting the public's awareness of using radiation. Of the students in the 79 schools sampled, 24%(177) were in 4 year colleges and 146 were junior colleges in educational statistics service (http://cesi.kedi.re.kr) In November 2010 1,945 students were selected as a sample, and they were given surveys on the need of using radiation in different fields. As a result, both between students majoring in radiation and non-radiation related studies showed a high level of understanding the need for radiation in the medical field and showed a low level of understanding of the need for radiation in the agricultural field. In all 6 fields of radiation use, students majoring in radiation related studies showed higher levels of understanding for the need to use radiation than students majoring in radiation and non-radiation related studies. In each field, male students and those who have experience medical radiation and relevant education had higher level of understanding. This shows we need to improve the understanding of the cases of female students and those who have not had experiences with medical radiation and to provide relevant education through various kinds of information. The characteristics of the groups that are shown in the results of this study are considered to be helpful for efficiently for project promoting the public's awareness of using radiation.

Transition radiation and diffraction radiation. Similarities and differences

International Nuclear Information System (INIS)

Potylitsyn, A.P.

1998-01-01

The characteristics of diffraction radiation (DR), i.e. radiation of the charged particle moving near conducting target have been considered for an ultrarelativistic case. The simple expressions for DR fields for the semi-infinite ideal conducting target have been derived. The close connection between transition radiation (TR) and DR has been shown. The effect of finite transversal sizes of target on TR characteristics has been evaluated. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Radiation treatment of foodstuffs

International Nuclear Information System (INIS)

Luther, T.; Huebner, G.

1990-10-01

In addition to fundamental demands on radiation and safety engineering of irradiation facilities, the necessity arises to optimize irradiation conditions by using facilities to capacity and thus reducing irradiation costs. The following subjects are dealt with in detail: rehabilitation of a pilot plant for radiation treatment of onions; examination of radiation resistance of components and equipment parts of food irradiation facilities; chemical dosimetry; relative measurement of the intensity of radioactive sources; thermo- and chemiluminescence to prove irradiation of foodstuffs; radiation induced sprout inhibition of potatoes; laboratory tests of delayed maturation of tomatoes; radiation treatment of strawberries; radiation treatment of forage; radiation induced sprout inhibition of acid-treated onions; radiation treatment of starch and potatoe products; radiation treatment of cosmetics; the universal radiation source UNI 88/26 for gamma irradiation facilities; microbiological aspects of food irradiation, and introduction of chicken irradiation on an industrial scale. (BBR) [de

Anti-diffusive radiation flow in the cooling layer of a radiating shock

International Nuclear Information System (INIS)

McClarren, Ryan G.; Paul Drake, R.

2010-01-01

This paper shows that for systems with optically thin, hot layers, such as those that occur in radiating shocks, radiation will flow uphill: radiation will flow from low to high radiation energy density. These are systems in which the angular distribution of the radiation intensity changes rapidly in space, and in which the radiation in some region has a pancaked structure, whose effect on the mean intensity will be much larger than the effect on the scalar radiation pressure. The salient feature of the solution to the radiative transfer equation in these circumstances is that the gradient of the radiation energy density is in the same direction as the radiation flux, i.e. radiation energy is flowing uphill. Such an anti-diffusive flow of energy cannot be captured by a model where the spatial variation of the Eddington factor is not accounted for, as in flux-limited diffusion models or the P 1 equations. The qualitative difference between the two models leads to a monotonic mean intensity for the diffusion model whereas the transport mean intensity has a global maximum in the hot layer. Mathematical analysis shows that the discrepancy between the diffusion model and the transport solution is due to an approximation of exponential integrals using a simple exponential.

TH-A-BRD-01: Radiation Biology for Radiation Therapy Physicists

International Nuclear Information System (INIS)

Orton, C; Borras, C; Carlson, D

2014-01-01

Mechanisms by which radiation kills cells and ways cell damage can be repaired will be reviewed. The radiobiological parameters of dose, fractionation, delivery time, dose rate, and LET will be discussed. The linear-quadratic model for cell survival for high and low dose rate treatments and the effect of repopulation will be presented and discussed. The rationale for various radiotherapy techniques such as conventional fractionation, hyperfractionation, hypofractionation, and low and high dose rate brachytherapy, including permanent implants, will be presented. The radiobiological principles underlying radiation protection guidelines and the different radiation dosimetry terms used in radiation biology and in radiation protection will be reviewed. Human data on radiation induced cancer, including increases in the risk of second cancers following radiation therapy, as well as data on radiation induced tissue reactions, such as cardiovascular effects, for follow up times up to 20–40 years, published by ICRP, NCRP and BEIR Committees, will be examined. The latest risk estimates per unit dose will be presented. Their adoption in recent radiation protection standards and guidelines and their impact on patient and workers safety in radiotherapy will be discussed. Biologically-guided radiotherapy (BGRT) provides a systematic method to derive prescription doses that integrate patient-specific information about tumor and normal tissue biology. Treatment individualization based on patient-specific biology requires the identification of biological objective functions to facilitate the design and comparison of competing treatment modalities. Biological objectives provide a more direct approach to plan optimization instead of relying solely on dose-based surrogates and can incorporate factors that alter radiation response, such as DNA repair, tumor hypoxia, and relative biological effectiveness. We review concepts motivating biological objectives and provide examples of how

TH-A-BRD-01: Radiation Biology for Radiation Therapy Physicists

Energy Technology Data Exchange (ETDEWEB)

Orton, C [Wayne State University, Grosse Pointe, MI (United States); Borras, C [Radiological Physics and Health Services, Washington, DC (United States); Carlson, D [Yale University School of Medicine, New Haven, CT (United States)

2014-06-15

Mechanisms by which radiation kills cells and ways cell damage can be repaired will be reviewed. The radiobiological parameters of dose, fractionation, delivery time, dose rate, and LET will be discussed. The linear-quadratic model for cell survival for high and low dose rate treatments and the effect of repopulation will be presented and discussed. The rationale for various radiotherapy techniques such as conventional fractionation, hyperfractionation, hypofractionation, and low and high dose rate brachytherapy, including permanent implants, will be presented. The radiobiological principles underlying radiation protection guidelines and the different radiation dosimetry terms used in radiation biology and in radiation protection will be reviewed. Human data on radiation induced cancer, including increases in the risk of second cancers following radiation therapy, as well as data on radiation induced tissue reactions, such as cardiovascular effects, for follow up times up to 20–40 years, published by ICRP, NCRP and BEIR Committees, will be examined. The latest risk estimates per unit dose will be presented. Their adoption in recent radiation protection standards and guidelines and their impact on patient and workers safety in radiotherapy will be discussed. Biologically-guided radiotherapy (BGRT) provides a systematic method to derive prescription doses that integrate patient-specific information about tumor and normal tissue biology. Treatment individualization based on patient-specific biology requires the identification of biological objective functions to facilitate the design and comparison of competing treatment modalities. Biological objectives provide a more direct approach to plan optimization instead of relying solely on dose-based surrogates and can incorporate factors that alter radiation response, such as DNA repair, tumor hypoxia, and relative biological effectiveness. We review concepts motivating biological objectives and provide examples of how

Radiation myelopathy

Energy Technology Data Exchange (ETDEWEB)

Howell, D A [Derbyshire Royal Infirmary, Derby (UK)

1979-10-01

Following high-dose radiotherapy treatment of tumours, there is a risk of destructive radiation myelopathy developing a few months later as a result of spinal cord irradiation. The emphasis of the present article is on the mechanism of the development of radiation myelopathy. It is suggested that, in the irradiated segments, the normal endothelial cells lining the penetrating arteries and capillaries are replaced by abnormal cells during the latent period. Radiation-induced mutations or chromosomal aberrations are contained in these cells, thus provoking an immunological response. During the attempted rejection of these cells, protein-rich plasma filtrate is leaked into the artery walls and nervous tissue, causing the destructive myelopathy. The signs of paralysis of spinal cord function may be caused either by infarcts or by oedema of the white matter. Since both diagnosis and treatment are difficult, it is necessary to concentrate on prevention by, whenever possible, reducing radiation doses to below tolerance limits during radiotherapy. As regards radiotherapy in children, it is currently believed that there is little or no difference in radiation tolerance between the child and the adult nervous system. Some early benign forms of radiation myelopathy are also briefly discussed.

Radiation myelopathy

International Nuclear Information System (INIS)

Howell, D.A.

1979-01-01

Following high-dose radiotherapy treatment of tumours, there is a risk of destructive radiation myelopathy developing a few months later as a result of spinal cord irradiation. The emphasis of the present article is on the mechanism of the development of radiation myelopathy. It is suggested that, in the irradiated segments, the normal endothelial cells lining the penetrating arteries and capillaries are replaced by abnormal cells during the latent period. Radiation-induced mutations or chromosomal aberrations are contained in these cells, thus provoking an immunological response. During the attempted rejection of these cells, protein-rich plasma filtrate is leaked into the artery walls and nervous tissue, causing the destructive myelopathy. The signs of paralysis of spinal cord function may be caused either by infarcts or by oedema of the white matter. Since both diagnosis and treatment are difficult, it is necessary to concentrate on prevention by, whenever possible, reducing radiation doses to below tolerance limits during radiotherapy. As regards radiotherapy in children, it is currently believed that there is little or no difference in radiation tolerance between the child and the adult nervous system. Some early benign forms of radiation myelopathy are also briefly discussed. (UK)

Radiation medicine

International Nuclear Information System (INIS)

1991-01-01

This booklet has been produced by UKAEA and the Marie Curie Memorial Foundation to give some basic information about what radiation is and how it is used in day to day diagnosis and treatment. It will be of interest to people undergoing treatment, their relatives and friends, and anyone who wants to know more about this important area. After a brief historical introduction the booklet explains what radiation is, the natural and man-made sources of radiation, how it is produced and how X-rays are used in medical diagnosis and treatment. The radiation protection measures taken and safety standards followed are mentioned. (author)

Medical students' knowledge of ionizing radiation and radiation protection.

Science.gov (United States)

Hagi, Sarah K; Khafaji, Mawya A

2011-05-01

To assess the knowledge of fourth-year medical students in ionizing radiation, and to study the effect of a 3-hour lecture in correcting their misconceptions. A cohort study was conducted on fourth-year medical students at King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia during the academic year 2009-2010. A 7-question multiple choice test-type questionnaire administered before, and after a 3-hour didactic lecture was used to assess their knowledge. The data was collected from December 2009 to February 2010. The lecture was given to 333 (72%) participants, out of the total of 459 fourth-year medical students. It covered topics in ionizing radiation and radiation protection. The questionnaire was validated and analyzed by 6 content experts. Of the 333 who attended the lecture, only 253 (76%) students completed the pre- and post questionnaire, and were included in this study. The average student score improved from 47-78% representing a gain of 31% in knowledge (p=0.01). The results indicated that the fourth-year medical students' knowledge regarding ionizing radiation and radiation protection is inadequate. Additional lectures in radiation protection significantly improved their knowledge of the topic, and correct their current misunderstanding. This study has shown that even with one dedicated lecture, students can learn, and absorb general principles regarding ionizing radiation.

Travel for the 2004 American Statistical Association Biannual Radiation Meeting: "Radiation in Realistic Environments: Interactions Between Radiation and Other Factors

Energy Technology Data Exchange (ETDEWEB)

Brenner, David J.

2009-07-21

The 16th ASA Conference on Radiation and Health, held June 27-30, 2004 in Beaver Creek, CO, offered a unique forum for discussing research related to the effects of radiation exposures on human health in a multidisciplinary setting. The Conference furnishes investigators in health related disciplines the opportunity to learn about new quantitative approaches to their problems and furnishes statisticians the opportunity to learn about new applications for their discipline. The Conference was attended by about 60 scientists including statisticians, epidemiologists, biologists and physicists interested in radiation research. For the first time, ten recipients of Young Investigator Awards participated in the conference. The Conference began with a debate on the question: “Do radiation doses below 1 cGy increase cancer risks?” The keynote speaker was Dr. Martin Lavin, who gave a banquet presentation on the timely topic “How important is ATM?” The focus of the 2004 Conference on Radiation and Health was Radiation in Realistic Environments: Interactions Between Radiation and Other Risk Modifiers. The sessions of the conference included: Radiation, Smoking, and Lung Cancer Interactions of Radiation with Genetic Factors: ATM Radiation, Genetics, and Epigenetics Radiotherapeutic Interactions The Conference on Radiation and Health is held bi-annually, and participants are looking forward to the 17th conference to be held in 2006.

No 592 - Radiation Act

International Nuclear Information System (INIS)

1991-01-01

This Act will enter into force on 1 January 1992. The scope of the Act is extensive as, in addition to ionizing radiation, it will also apply to activities involving exposure to natural radiation and non-ionizing radiation. Its purpose is to prevent and restrict harmful effects to health resulting from radiation. The basic principles of the Act are that the practice involving radiation should be justified; radiation protection should be optimized; and radiation doses should be as low as reasonably achievable. Licensed organisations using radiation will be responsible for the safety of the activity involving exposure to radiation and for having available the appropriate expertise to this effect. The required so-called safety licence provides the regulatory control to ensure that radiation is used sensibly, that the equipment and shields are technically acceptable and the operating personnel is competent, and that the radioactive waste is dealt with appropriately. The Radiation Act will also apply to nuclear activities within the scope of the 1987 Nuclear Energy Act [fr

Applied physics of external radiation exposure dosimetry and radiation protection

CERN Document Server

Antoni, Rodolphe

2017-01-01

This book describes the interaction of living matter with photons, neutrons, charged particles, electrons and ions. The authors are specialists in the field of radiation protection. The book synthesizes many years of experiments with external radiation exposure in the fields of dosimetry and radiation shielding in medical, industrial and research fields. It presents the basic physical concepts including dosimetry and offers a number of tools to be used by students, engineers and technicians to assess the radiological risk and the means to avoid them by calculating the appropriate shields. The theory of radiation interaction in matter is presented together with empirical formulas and abacus. Numerous numerical applications are treated to illustrate the different topics. The state of the art in radiation protection and dosimetry is presented in detail, especially in the field of simulation codes for external exposure to radiation, medical projects and advanced research. Moreover, important data spread in differ...

New Finnish radiation law

International Nuclear Information System (INIS)

Niittyla, A.

1992-01-01

The new Finnish Radiation Act will enter into force on 1.1.1992. The Act aims to protect man's health against the harmful effects of radiation. The Act applies to the utilization of ionising radiation and natural radiation as well as non-ionising radiation. It emphasises the fact that a licensed organization or entrepreneur carrying out a practice which causes radiation exposure is responsible for the safety of the activity. The organization or entrepreneur in question is also obliged to take care of radioactive waste. The provisions of the Radiation Act which apply to monitoring of worker exposure are also applied to the use of nuclear energy. Activities involving the use of radiation and the use of nuclear energy are regulated by one authority, the Finnish Centre for Radiation and Nuclear Safety. (author)

Hazards of radiation exposure

International Nuclear Information System (INIS)

Solomon, S.B.

1982-01-01

Radiation induced carcinogenesis and mutagenesis form the main risks to health from exposure to low levels of radiation. There is scant data on somatic and genetic risks at environmental and occupational levels of radiation exposure. The available data on radiation induced carcinogenesis and mutagenesis are for high doses and high dose rates of radiation. Risk assessments for low level radiation are obtained using these data, assuming a linear dose-response relationship. During uranium mining the chief source of radiation hazard is inhalation of radon daughters. The correlation between radon daughter exposure and the increased incidence of lung cancer has been well documented. For radiation exposures at and below occupational limits, the associated risk of radiation induced cancers and genetic abnormalities is small and should not lead to a detectable increase over naturally occurring rates

Training in radiation protection and the safe use of radiation sources

International Nuclear Information System (INIS)

2001-01-01

The need for education and training in the various disciplines of radiation protection has long been recognized by the IAEA, the International Labour Organization (ILO), the United Nations Educational, Scientific and Cultural Organization, the World Health Organization and the Pan American Health Organization (PAHO). This need has been partially met through the many training courses undertaken by these organizations, either individually or in collaboration. The IAEA has assisted developing Member States in the training of specialists in radiation protection and safety through its organized educational and specialized training courses, workshops, seminars, fellowships and scientific visits. Training is an important means of promoting safety culture and enhancing the level of competence of personnel involved in radiation protection activities, and has acquired a place in the IAEA's programme accordingly. For example, the IAEA Post-graduate Educational Course in Radiation Protection and the Safe Use of Radiation Sources is regularly offered in countries around the world, and has been provided in Arabic, English, French, Spanish and Russian. The training provided by the IAEA is primarily aimed at regulators, professionals working in radiation protection and those responsible for the development of training programmes in their own countries. The importance of adequate and appropriate training for all those working with ionizing radiation has been highlighted by the results of the IAEA's investigations of radiological accidents. A significant contributory factor in a number of the accidents has been a lack of adequate training, which gave rise to errors with serious consequences. This report provides assistance in organizing training and complying with the requirements on training of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS). The previous version of this report. Technical Reports

Space radiation environment

International Nuclear Information System (INIS)

Garrett, H.B.

1998-01-01

Coupled with the increasing concern over trapped radiation effects on microelectronics, the availability of new data, long term changes in the Earth's magnetic field, and observed variations in the trapped radiation fluxes have generated the need for better, more comprehensive tools for modeling and predicting the Earth's trapped radiation environment and its effects on space systems. The objective of this report is to describe the current status of those efforts and review methods for attacking the issues associated with modeling the trapped radiation environment in a systematic, practical fashion. The ultimate goal will be to point the way to increasingly better methods of testing, designing, and flying reliable microelectronic systems in the Earth's radiation environment. The review will include a description of the principal models of the trapped radiation environment currently available--the AE8 and AP8 models. Recent results rom radiation experiments on spacecraft such as CRRES, SAMPEX, and CLEMENTINE will then be described. (author)

Effect of radiation environment on radiation use efficiency and growth of sunflower

International Nuclear Information System (INIS)

Bange, M.P.; Hammer, G.L.; Rickert, K.G.

1997-01-01

The level of incident radiation and the proportion of radiation that is diffuse affects radiation use efficiency (RUE) in crops. However, the degree of this effect, and its importance to growth and yield of sunflower (Helianthus annuus L.) have not been established. A field experiment was conducted to investigate the effects of radiation environment on RUE, growth, and yield of sunflower. A fully irrigated crop was sown on an alluvial-prairie soil (Fluventic Haplustoll) and was exposed to three distinct radiation environments. In two treatments, the level of incident radiation was reduced by 14 and 20% by suspending two different types of polyethylene plastic films well above the crop. In addition to the reductions in incident radiation, the proportion of radiation that was diffuse was increased by about 14% in these treatments. Lower incident radiation and increased proportion of diffuse radiation had no effect on total biomass, phenology, leaf area, and the canopy light extinction coefficient (k = 0.89). However, yield was reduced in shaded treatments due to smaller grain size and lower harvest index. Although crop RUE measured over the entire crop cycle (1.25 g/MJ) did not differ significantly among treatments, there was a trend where RUE compensated for less intercepted incident radiation. Theoretical derivations of the response of RUE to different levels of incident radiation supported this finding. Shaded sunflower crops have the ability to produce biomass similar to unshaded crops by increasing RUE, but have lower harvest indices

Carcinoma of the anal canal: radiation or radiation plus chemotherapy

International Nuclear Information System (INIS)

Cummings, B.J.

1983-01-01

An editorial is presented which discusses the treatment of carcinoma of the anal canal. Following the initial report of the successful preoperative use of combined chemotherapy and radiation by Nigro in 1974, several centers have confirmed the effectiveness of such combinations either as preoperative or as definitive treatment of anal carcinomas, and many patients are now being referred for radiation therapy. The article by Cantril in this issue describe the successful treatment of anal carcinomas by radiation alone, and raises the important issue of whether radiation plus chemotherapy is more effective treatment than radiation alone for squamous or cloacogenic carcinomas arising in the anal canal or perianal area. Several studies are cited

Chemical and radiation injuries

International Nuclear Information System (INIS)

Hugo, M.J.

1981-01-01

The paper is a discussion of radiation injuries and the treatment thereof. Radiation injuries are mainly caused as a result of nuclear leaks or nuclear bomb explosions. Such an explosion is usually accompanied by a light flash, noise, heat radiation and nuclear radiation which can all caurse various types of injuries. The general effect of radioactive radiation is discussed. The seriousness of the situation where the whole body was exposed to nuclear radiation, depends on the total radiation dose received and varies from person to person. The progress of radiation sickness is described. Mention is also made of long term radiation effects. The emergency treatment of the injured before specialised aid is available, is discussed. The primary aim of treatment is to save life and to prevent further injuries and complications. Injured people must be removed as far as possible from the point of maximum radiation. Attention must also be given to decontamination

Ionizing radiation in environment

International Nuclear Information System (INIS)

Jandl, J.; Petr, I.

1988-01-01

The basic terms are explained such as the atom, radioactivity, nuclear reaction, interaction of ionizing radiation with matter, etc. The basic dosimetric variables and units and properties of radionuclides and ionizing radiation are given. Natural and artificial sources of ionizing radiation are discussed with regard to the environment and the propagation and migration of radionuclides is described in the environment to man. The impact is explained of ionizing radiation on the cell and the somatic and genetic effects of radiation on man are outlined. Attention is devoted to protection against ionizing radiation and to radiation limits, also to the detection, dosimetry and monitoring of ionizing radiation in the environment. (M.D.). 92 figs., 40 tabs. 74 refs

External radiation surveillance

Energy Technology Data Exchange (ETDEWEB)

Antonio, E.J.

1995-06-01

This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

External radiation surveillance

International Nuclear Information System (INIS)

Antonio, E.J.

1995-01-01

This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site

ISLSCP II Surface Radiation Budget (SRB) Radiation Data

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set contains global Surface Radiation Budget (SRB) and a few top-of-atmosphere (TOA) radiation budget parameters on a 1-degree x 1-degree spatial...

The technique on handling radiation

International Nuclear Information System (INIS)

1997-11-01

This book describes measurement of radiation and handling radiation. The first part deals with measurement of radiation. The contents of this part are characteristic on measurement technique of radiation, radiation detector, measurement of energy spectrum, measurement of radioactivity, measurement for a level of radiation and county's statistics on radiation. The second parts explains handling radiation with treating of sealed radioisotope, treating unsealed source and radiation shield.

Radiation protection in radionuclide investigations

International Nuclear Information System (INIS)

Taylor, D.M.

1985-01-01

The subject is covered in sections: introduction; radiation and radioactivity; alpha particles; beta particles; neutrons; electromagnetic radiation; units of radioactivity and radiation; biological effects of radiation; the philosophy of radiation protection (ALARA principle); practical aspects of radiation protection; work with unsealed radiation sources; radionuclide studies in experimental animals; radiation safety during clinical investigations; legislative control of radiation work; radioactive waste disposal; emergency procedures; conclusion. (U.K.)

Radiation effects on materials in high-radiation environments

International Nuclear Information System (INIS)

Weber, W.J.; Mansur, L.K.; Clinard, F.W. Jr.; Parkin, D.M.

1991-01-01

A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs. (orig.)

Prostaglandis and radiation

International Nuclear Information System (INIS)

Romantsev, E.F.; Blokhina, V.D.; Zhulanova, Z.I.; Koshcheenko, I.N.; Nikol'skij, A.V.; Filippovich, I.V.

1984-01-01

It was established that some biochemical distortions in the brain of animals, subjected to superlethal doses of ionizing radiation don't develope; the starting mechanisms of a radiation damage can be fundamentally another, as compared to the medullar and intestinal forms of radiation sickness. It enables to assume that observed changes in activity of prostaglandin-synthetase system during irradiation by 250 Gr dose are based on earlier formed changes in membrane permeability and distortion of receptor cell activity. Investigations of the effect of radiation damage modificators give additional information when studying the primary biochemical processes, initiating radiation sickness

Radiation and DNA

Energy Technology Data Exchange (ETDEWEB)

Riabchenko, N I

1979-01-01

Consideration is given to the effects of ionizing radiation on the structure of DNA. Physical and chemical methods of determining radiation damage to the primary (polynucleotide chain and nitrogenous base) and secondary (helical) structure of DNA are discussed, and the effects of ionizing radiation on deoxyribonucleoprotein complexes are considered. The radiolysis of DNA in vitro and in bacterial and mammalian cells is examined and cellular mechanisms for the repair of radiation-damaged DNA are considered, taking into account single-strand and double-strand breaks, gamma-radiation damage and deoxyribonucleoprotein-membrane complex damage. Postradiation DNA degradation in bacteria and lymphatic cells is also discussed.

Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms

International Nuclear Information System (INIS)

Sidky, Emil Y.; Pan Xiaochuan; Reiser, Ingrid S.; Nishikawa, Robert M.; Moore, Richard H.; Kopans, Daniel B.

2009-01-01

Purpose: The authors develop a practical, iterative algorithm for image-reconstruction in undersampled tomographic systems, such as digital breast tomosynthesis (DBT). Methods: The algorithm controls image regularity by minimizing the image total p variation (TpV), a function that reduces to the total variation when p=1.0 or the image roughness when p=2.0. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets. The fact that the tomographic system is undersampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) Reduction in the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this dual role of image regularity in undersampled tomography. Results: The proposed image-reconstruction algorithm is applied to three clinical DBT data sets. The DBT cases include one with microcalcifications and two with masses. Conclusions: Results indicate that there may be a substantial advantage in using the present image-reconstruction algorithm for microcalcification imaging.

MRI to predict prostate growth and development in children, adolescents and young adults.

Science.gov (United States)

Ren, Jing; Liu, Huijia; Wang, He; Wen, Didi; Huang, Xufang; Ren, Fang; Huan, Yi

2015-02-01

The purpose of this study was to investigate the use of MRI in predicting prostate growth and development. A total of 1,500 healthy male volunteers who underwent MRI of the pelvis were included in this prospective study. Subjects were divided into five groups according to age (group A, 2-5 years; group B, 6-10 years; group C, 11-15 years; group D, 16-20 years; group E, 21-25 years). Total prostate volume (TPV) as well as prostate central zone (CZ) and peripheral zone (PZ) were measured and evaluated on MRI. Data of the different groups were compared using variance analysis, Scheffé's method, Kruskal-Wallis H-test, and Pearson's correlation. Statistical significance was inferred at P development scores were 0.08, 0.69, 1.56, 2.38, and 2.74, respectively. Both TPVs and zonal anatomy scores varied significantly among the five groups (P = 0.000). TPV and zonal anatomy score increased with increasing age. MRI provides a reliable quantitative reference for prostate growth and development. • When and how the prostate develops after birth remains unclear. • Prostate volume increases rapidly after the age of 10 years. • MRI provides a reliable objective and quantitative reference for prostate growth and development.

Radiation collimator for use with high energy radiation beams

International Nuclear Information System (INIS)

Malak, S.P.

1978-01-01

A collimator is described for use with a beam of radiation, and in particular, for use in controlling the cross-sectional size and shape of the radiation beam and intercepting undesired off-focus radiation in an x-ray apparatus. The collimator is positioned adjacent to the source of radiation and embodies a plurality longitudinally extending leaves pivotally mounted on and between two supports, the leaves move about their pivots to close overlapping relation to define a hollow cone. The cone defines an aperture at its narrow end which can be adjusted in size and shape by rotation of the two supports which are adaptable to being moved one relative to the other, to cause an expansion or contraction of the hollow cone and correspondingly an increase or decrease of the cross-sectional size and/or shape of the radiation beam passing through the aperture

Working safely with ionising radiation

International Nuclear Information System (INIS)

McDowell, D.J.

1990-01-01

A small leaflet provides information on working safely with ionizing radiation. Topics covered include the types of radiation, radiological units, external radiation, contamination and internal radiation, methods of protection form radiation, radiation monitors, protective clothing for contamination, personal dosemeters, radiation dose limits for classified workers and finally the Ionising Radiations Regulations 1985. (UK)

New legislative regulations for ensuring radiation protection using ionizing radiation sources in medicine

International Nuclear Information System (INIS)

Boehm, K.

2018-01-01

European Commission Directive No. 2013/59 / EURATOM laying down basic safety requirements for the provision of radiation protection regulates the provision of radiation protection for workers with radiation sources and residents in all areas of use of ionizing radiation sources. This Directive also addresses radiation protection in the use of ionizing radiation sources in medicine. The European Commission Directive regulates the requirements for radiation protection but also extends to its scope and provisions on the use of medical radiation sources (so-called m edical exposure ) in the scope of further legislation in the field of health care, which has to be amended and modified or possibly issued new. It was necessary in the preparation of the new act on radiation protection to amend simultaneously Act no. 576/2004 on the provision of health care and services related to provision of health care and Act no. 578/2004 on Health care Providers, Health care Professionals and Organizations in Health Care and to prepare a series of implementing regulations not only to the Law on Radiation Protection but also to the Laws governing the Provision of Health Care. The paper presents changes to existing legislation on radiation protection in medical radiation and new requirements for the construction and operation of health workplaces with radiation sources, the protection of the health of patients, the requirements for instrumentation used for medical radiation and radiological instrumentation tests. (authors)

Radiation microbiology relevant to radiation processing

International Nuclear Information System (INIS)

Tallentire, A.

1979-01-01

The subject is discussed under the following headings: typical background studies involving laboratory models (measurement of radiation responses of different organisms, alone or on or in products; isolation of radiation resistant organisms from products and product environments; measurement of levels of preirradiation microbial contamination ('bioburden')); supplementary studies involving naturally occurring microbial contaminants (unit medical products; microbiological quality assurance; products in bulk; animal diet study). (U.K.)

Radiation meter

Energy Technology Data Exchange (ETDEWEB)

Burgess, P H

1990-05-30

Measuring means comprising first and second silicon PIN diode detectors both being covered with a thin layer of conducting material and the second detector being additionally covered with a relatively thick layer of material, the thickness being chosen such that beta radiation dose rate can be measured in beta radiation fields of high or medium energy, and in the presence of X and gamma radiation. (author). 2 figs.

Radiation chemistry

Energy Technology Data Exchange (ETDEWEB)

None

1973-07-01

Research progress is reported on radiation chemistry of heavy elements that includes the following topics: radiation chemistry of plutonium in nitric acid solutions (spectrophotometric analysis and gamma radiolysis of Pu(IV) and Pu(VI) in nitric acid solution); EPR studies of intermediates formed in radiolytic reactions with aqueous medium; two-phase radiolysis and its effect on the distribution coefficient of plutonium; and radiation chemistry of nitric acid. (DHM)

Cherenkov radiation; La radiation Cerenkov

Energy Technology Data Exchange (ETDEWEB)

Hubert, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

When the radioactivity has been discovered, it was observed by researchers that different materials as mineral salts or solutions were emitting a weak light when submitted to radioactivity beams. At the beginning it has been thought that it was fluorescent light. In 1934, Cherenkov, a russian physicist, worked on the luminescence of uranyl salts solutions caused by gamma radiation and observed a very weak light was emitted by pure liquid. After further studies, he concluded that this phenomena was different from fluorescence. Since then, it has been called Cherenkov effect. This blue light emission is produced when charged particles are going through a transparent medium with an upper velocity than light velocity. This can happen only in medium with large refractive index as water or glass. It also presents its different properties discovered afterwards. The different applications of the Cherenkov radiation are discussed as counting techniques for radiation detectors or comic ray detectors. (M.P.)

Radiation curing

International Nuclear Information System (INIS)

Wendrinsky, J.

1987-04-01

In the beginning of the seventies the two types of radiation sources applied in industrial processes, electron radiation and UV, had been given rather optimistic forecasts. While UV could succeed in the field of panel and film coating, electron radiation curing seems to gain success in quite new fields of manufacturing. The listing of the suggested applications of radiation curing and a comparison of both advantages and disadvantages of this technology are followed by a number of case studies emphasizing the features of these processes and giving some examplary calculations. The data used for the calculations should provide an easy calculation of individual manufacturing costs if special production parameters, investment or energy costs are employed. (Author)

Health protection of radiation workers

International Nuclear Information System (INIS)

Norwood, W.D.

1975-01-01

This textbook is addressed to all those concerned with the protection of radiation workers. It provides full coverage of the implications of radiation in exposed workers, and, after a chapter outlining, in simple terms, the basic facts about radiation, deals with measurement of ionising radiation; radiation dosimetry; effectiveness of absorbed dose; general biological effects of ionising radiation; somatic effects of radiation; the acute radiation syndrome; other somatic effects; hereditary effects; radiation protection standards and regulations; radiation protection; medical supervision of radiation workers; general methods of diagnosis and treatment; metabolism and health problems of some radioisotopes; plutonium and other transuranium elements; radiation accidents; emergency plans and medical care; atomic power plants; medico-legal problems

Occupational radiation protection: Protecting workers against exposure to ionizing radiation. Contributed papers

International Nuclear Information System (INIS)

2003-07-01

Occupational exposure to ionizing radiation can occur in a range of industries, mining and milling; medical institutions, educational and research establishments and nuclear fuel cycle facilities. The term 'occupational exposure' refers to the radiation exposure incurred by a worker, which is attributable to the worker's occupation and committed during a period of work. According to the latest (2000) Report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), an estimated 11 million workers are monitored for exposure to ionizing radiation. They incur radiation doses attributable to their occupation, which range from a small fraction of the global average background exposure to natural radiation up to several times that value. It should be noted that the UNSCEAR 2000 Report describes a downward trend in the exposure of several groups of workers, but it also indicates that occupational exposure is affecting an increasingly large group of people worldwide. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), which are co-sponsored by, inter alia, the International Atomic Energy Agency (IAEA), the International Labour Organization (ILO), the OECD Nuclear Energy Agency (NEA) and the World Health Organization (WHO), establish a system of radiation protection which includes radiation dose limits for occupational exposure. Guidance supporting the requirements of the BSS for occupational protection is provided in three interrelated Safety Guides, jointly sponsored by the IAEA and the ILO. These Guides describe, for example, the implications for employers in discharging their main responsibilities (such as setting up appropriate radiation protection programmes) and similarly for workers (such as properly using the radiation monitoring devices provided to them). The IAEA i organized its first International Conference on Occupational Radiation Protection. The

The physics of radiation protection

International Nuclear Information System (INIS)

Doerschel, B.; Schuricht, V.; Steuer, J.

1996-01-01

The book is aimed at both practising specialists and scientists wishing to learn about the fundamental science of radiation protection. The first part of the book, 'Physical Fundamentals of Radiation Protection', presents a concise description of radiation sources and radiation fields, interaction of radiation with matter, radiation effects and radiation damage, basic concept of radiation protection, radiation exposure of man, radiation protection measuring techniques and physical fundamentals for limiting radiation exposure. The second part, 'Calculational Exercises for Radiation Protection' is intended to supplement the first part by carrying out relevant calculations, amending and adding special aspects and to give guidance in solving practical problems. The book is written for scientists as well as for students and staff working in nuclear facilities, hospitals and institutions responsible for radiation and environmental protection. (UK)

Radiation education in school

International Nuclear Information System (INIS)

Shishido, Teruko; Higashijima, Emiko; Hisajima, Michihiro

2005-01-01

Part of goals of general education of physics is to provide students for basic knowledge on radiation. This includes understanding of both its risks and benefits. Students should know how to protect and defence from radiation but they should not overwhelm the risk of radiation. Sometimes, students think that atomic power is so terrible and frightening that they keep away from use of atomic power. Basic knowledge about risks of radiation will reduce the excessive reaction or anxiety coming from radiation. It also makes people understand other possible risks and benefits of radiation accompanied by modern scientific technologies such as nuclear technologies. We believe that the radiation education is an essential requisite for the peaceful usage of nuclear energy and radiation technology for the future. (author)

Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

International Nuclear Information System (INIS)

Cossairt, J.D.

1993-11-01

This report discusses the following topics: Composition of Accelerator Radiation Fields; Shielding of Electrons and Photons at Accelerators; Shielding of Hadrons at Accelerators; Low Energy Prompt Radiation Phenomena; Induced Radioactivity at Accelerators; Topics in Radiation Protection Instrumentation at Accelerators; and Accelerator Radiation Protection Program Elements

Radiation modification of materials

International Nuclear Information System (INIS)

Pikaev, A.K.

1987-01-01

Industrial and radiation chemical processes of material modification based on cross-linking of polymers as a result of radiation are considered. Among them are production of cables and rods with irradiated modified insulation, production of hardened and thermo-shrinkaging polymer products (films, tubes, fashioned products), production of radiation cross-linked polyethylene foam, technology of radiation vulcanization of elastomers. Attention is paid to radiation plants on the basis of γ-sources and electron acceleratos as well as to radiation conditions

Pulsed radiation decay logging

International Nuclear Information System (INIS)

Mills, W.R. Jr.

1983-01-01

There are provided new and improved well logging processes and systems wherein the detection of secondary radiation is accomplished during a plurality of time windows in a manner to accurately characterize the decay rate of the secondary radiation. The system comprises a well logging tool having a primary pulsed radiation source which emits repetitive time-spaced bursts of primary radiation and detector means for detecting secondary radiation resulting from the primary radiation and producing output signals in response to the detected radiation. A plurality of measuring channels are provided, each of which produces a count rate function representative of signals received from the detector means during successive time windows occurring between the primary radiation bursts. The logging system further comprises means responsive to the measuring channels for producing a plurality of functions representative of the ratios of the radiation count rates measured during adjacent pairs of the time windows. Comparator means function to compare the ratio functions and select at least one of the ratio functions to generate a signal representative of the decay rate of the secondary radiation

Ionizing and non-ionizing radiations

International Nuclear Information System (INIS)

1994-01-01

The monograph is a small manual to get a knowledge of ionizing and non-ionizing radiations. The main chapters are: - Electromagnetic radiations - Ionizing and non-ionizing radiations - Non-ionizing electromagnetic radiations - Ionizing electromagnetic radiation - Other ionizing radiations - Ionizing radiation effects - The Nuclear Safety Conseil

Radiation preservation of maize

International Nuclear Information System (INIS)

Wasito.

1980-01-01

Radiation preservation of maize was carried out. Radiation doses and sources, shielding materials, packaging materials, chemical radiation effects, biological radiation effects, were discussed. Experimental methods, samples and accessories were also presented. (SMN)

Risk management of radiation therapy. Survey by north Japan radiation therapy oncology group

International Nuclear Information System (INIS)

Aoki, Masahiko; Abe, Yoshinao; Yamada, Shogo; Hareyama, Masato; Nakamura, Ryuji; Sugita, Tadashi; Miyano, Takashi

2004-01-01

A North Japan Radiation Oncology Group (NJRTOG) survey was carried out to disclose the risk management of radiation therapy. During April 2002, we sent questionnaires to radiation therapy facilities in northern Japan. There were 31 replies from 27 facilities. Many incidents and accidents were reported, including old cases. Although 60% of facilities had a risk management manual and/or risk manager, only 20% had risk management manuals for radiation therapy. Eighty five percent of radiation oncologists thought that incidents may be due to a lack of manpower. Ninety percent of radiation oncologists want to know the type of cases happened in other facilities. The risk management system is still insufficient for radiation therapy. We hope that our data will be a great help to develop risk management strategies for radiation therapy for all radiation oncologists in Japan. (author)

Radiation protection and regulatory aspects in the use of radiation sources

International Nuclear Information System (INIS)

Sen, Amit; Dash Sharma, P.K.; Sonawane, A.U.

2012-01-01

The uses of ionising radiation sources (i.e. radioisotopes and radiation generating equipment such as accelerators and X-ray machines) for multifarious applications in industry, medicine, agriculture, research and teaching have been significantly increasing all over the world. In India, the application of radiation sources in various fields has registered phenomenal growth during the last decade. The use of radiation sources mainly include radiation processing for food preservation and sterilization of healthcare products, radiotherapy for treatment of cancer, nuclear medicine for diagnosis and therapy, gamma chambers for several R and D studies, blood irradiators, industrial radiography for non destructive examinations of steel structures, industrial ionising radiation gauging devices for monitoring/measurement of on-line quality control parameters (e.g. thickness, level, density, moisture, elemental analysis), consumer products such as gaseous tritium light sources (GTLS), gaseous tritium light devices (GTLD), ionisation chamber smoke detectors (ICSD), fluorescent light starters, antistatic devices and incandescent gas mantles containing thorium etc. All these beneficial applications involve use of both sealed and unsealed radioactive sources and amount of radioactivity varies from few kBq (μCi) to hundreds of TBq (thousands of curies). Radiation sources emit ionising radiations and if not handled properly and safely, may give rise to potential exposures leading to an unacceptable hazard. Therefore, it is necessary to ensure a high standard of safety and reliability in handling of radiation equipment and sources through their careful design by ensuring adequate built-in-safety as per applicable national/international standard, safe operation and periodic maintenance procedures, safe transport from one place to another, secured storage when not in use, physical security to radiation sources, effective emergency response plans and preparedness, including safe

Radiation protection principles

International Nuclear Information System (INIS)

Ismail Bahari

2007-01-01

The presentation outlines the aspects of radiation protection principles. It discussed the following subjects; radiation hazards and risk, the objectives of radiation protection, three principles of the system - justification of practice, optimization of protection and safety, dose limit

Radiation protection training of radiation safety officers in Finland in 2008

International Nuclear Information System (INIS)

Havukainen, R.; Bly, R.; Markkanen, M.

2009-11-01

The Radiation and Nuclear Safety Authority (STUK) carried out a survey on the radiation protection training of radiation safety officers (RSO) in Finland in 2008. The aim of the survey was to obtain information on the conformity and uniformity of the training provided in different training organisations. A previous survey concerning radiation protection training was carried out in 2003. That survey determined the training needs of radiation users and radiation safety officers as well the radiation protection training included in vocational training and supplementary training. This report presents the execution and results of the survey in 2008. According to the responses, the total amount of RSO training fulfilled the requirements presented in Guide ST 1.8 in the most fields of competence. The emphasis of the RSO training differed between organisations, even for training in the same field of competence. Certain issues in Guide ST 1.8 were dealt quite superficially or even not at all in some training programmes. In some fields of competence, certain matters were entirely left to individual study. No practical training with radiation equipment or sources was included in the RSO training programme of some organisations. Practical training also varied considerably between organisations, even within the same field of competence. The duties in the use of radiation were often considered as practical training with radiation equipment and sources. Practical training from the point of view of a radiation safety officer was brought up in the responses of only one organisation. The number of questions and criteria for passing RSO exams also varied between organisations. Trainers who provided RSO training for the use of radiation in health care sectors had reached a higher vocational training level and received more supplementary training in radiation protection in the previous 5 years than trainers who provided RSO training for the use of radiation in industry, research, and

Cancer-causing radiation

International Nuclear Information System (INIS)

Ullrich, R.L.; Holland, J.M.; Storer, J.B.

1977-01-01

Radiation causes cancer. That simple fact was known by the early 1900s. Further, radiation can induce cancer in almost any tissue in animals and humans. But the cancer-causing dose may vary by 20-fold for different tissues in animals. Such variation is also seen in people who are exposed, typically, to low radiation doses. Hence, the minimum dose that causes human cancer is not known. Thus, the crucial question becomes what factors, including amount of exposure, trigger cancer. Radiation is divided into two types, ionizing and nonionizing. Of the two, ionizing radiation involves higher energies. Thus by ejecting electrons from molecules, charged particles called ion pairs are formed. They are short-lived, and often break down to form highly reactive free radicals, which are molecular fragments containing unpaired electrons. Nonionizing radiation, which involves ultraviolet light and micro- and radiowaves, causes molecular excitations such as vibrations and electron movement, but produces no ions. And though ultraviolet light causes skin cancer, ionizing radiation is, by far, the more potent carcinogen

Radiation-induced enteropathy

Energy Technology Data Exchange (ETDEWEB)

Sher, M.E.; Bauer, J. (Mount Sinai Hospital, New York, NY (USA))

1990-02-01

The incidence of chronic radiation enteritis appears to have risen in recent years due to the increasing utilization of radiotherapy for abdominal and pelvic malignancies. The etiology, pathogenesis, and management of radiation enteritis are discussed. Two case reports exemplify the progressive nature of the disease. Case 1 demonstrates the classical picture of multiple exacerbations and remissions of partial small bowel obstruction and the eventual need for surgical management ten years after radiation therapy. Case 2 presents the more severe sequelae of an acute perforation with a 14-yr latency period. Predisposing factors in the progression of radiation injury include excessive radiation, underlying cardiovascular disease, fixation of the bowel, and an asthenic habitus. In both cases, radiation injury was localized to a discrete segment of bowel; therefore, resection with a primary end-to-end anastomosis was performed. In addition, diseased bowel was eliminated and, therefore, would not cause further complications such as intractable bleeding or fistula formation. The review focuses on current knowledge which may be applied to the treatment and prevention of radiation enteritis.

Hawking radiation

Science.gov (United States)

Parentani, Renaud; Spindel, Philippe

2011-12-01

Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which escaping at infinity while the other is trapped inside the black hole horizon. It is named after the physicist Stephen Hawking who derived its existence in 1974. This radiation reduces the mass of black holes and is therefore also known as black hole evaporation.

Radiation regulation

International Nuclear Information System (INIS)

Braithwaite, J.; Grabosky, P.

1985-01-01

The five main areas of radiation regulation considered are radiation exposure in the mining of uranium and other minerals, exposure in the use of uranium in nuclear reactors, risks in the transport of radioactive materials and hazards associated with the disposal of used materials. In Australia these problems are regulated by mines departments, the Australian Atomic Energy Commission and radiation control branches in state health departments. Each of these instutional areas of regulation is examined

Perception of radiation hazards

International Nuclear Information System (INIS)

Sorenson, J.A.

1986-01-01

The health risks of radiation have been carefully studied and are relatively well understood in comparison with other risks to the human environment. Public perception of these risks often is distorted, due in part to lack of familiarity with the actual risk levels involved. There is a need for dissemination to the public of accurate information on radiation risks as well as to patients and volunteer subjects for studies involving radiation exposures. Often such information can be presented meaningfully by comparing the risks of radiation exposure with other, more familiar risks. Natural background radiation is a universally present and generally accepted source of risk, and thus serves as one reference against which to compare the risks of other radiation exposures. Natural background radiation averages about 100 mrem/yr, but much higher levels are encountered in some parts of the US (400 mrem/yr) and worldwide (2000 mrem/yr). These variations are due primarily to differences in cosmic ray intensity with altitude and in terrestrial radiation originating from soil and rocks. Radiation risks also may be compared with the risks of other human activities, both voluntary and involuntary. The former are useful for comparisons with the risks of voluntary radiation exposures such as occupational exposure and participation in medical or research procedures involving radiation. Involuntary radiation exposure, such as might result from the transportation and disposal of radioactive waste, poses a more complicated issue. Comparisons of such exposures to natural background radiation levels and their variations are helpful. Two other concepts that have been proposed for assessing the relative risk of low-level radiation exposure are de minimus risk and probability of causation. 28 references

Medical precautions of radiation diseases and radiation accidents

International Nuclear Information System (INIS)

Fehringer, Franz; Ludwig, Thomas

2009-01-01

The main topic deals essentially with the role of the Authorized Physician in industrial medicine, with the occupational diseases caused by ionizating radiation, with the tasks of regional radiation protection centers, and with the WHO REMPAN network. (orig.)

Introduction to radiation transport

International Nuclear Information System (INIS)

Olson, G.L.

1998-01-01

This lecture will present time-dependent radiation transport where the radiation is coupled to a static medium, i.e., the material is not in motion. In reality, radiation exerts a pressure on the materials it propagates through and will accelerate the material in the direction of the radiation flow. This fully coupled problem with radiation transport and materials in motion is referred to as radiation-hydrodynamics (or in a shorthand notation: rad-hydro) and is beyond the scope of this lecture

Construction of data base for radiation safety assessment of low dose ionizing radiation

International Nuclear Information System (INIS)

Saigusa, Shin

2001-01-01

Data base with an electronic text on the safety assessment of low dose ionizing radiation have been constructed. The contents and the data base system were designed to provide useful information to Japanese citizens, radiation specialists, and decision makers for a scientific and reasonable understanding of radiation health effects, radiation risk assessment, and radiation protection. The data base consists of the following four essential parts, namely, ORIGINAL DESCRIPTION, DETAILED INFORMATION, TOPIC INFORMATION, and RELATED INFORMATION. The first two parts of the data base are further classified into following subbranches: Radiobiological effects, radiation risk assessment, and radiation exposure and protection. (author)

Heart and radiation

Directory of Open Access Journals (Sweden)

Lauro Martins Júnior

2011-12-01

Full Text Available ABSTRATC The heart exposition to ionizing radiation may produce lesions in cardiac structures, acute (in most of cases benign and reversible, or months and even years later. There is a direct relationship of severity of lesions with radiation doses. The clinical picture receives a new denomination: radiation induced cardiopathy. The more frequent use of radiation in diagnosis and therapeutics increases the importance of their knowledge and especially their prevention.

Synchrotron-radiation research

International Nuclear Information System (INIS)

Cunningham, J.E.

1982-01-01

The use of radiation from synchrotron sources has started a renaissance in materials, physics, chemistry, and biology. Synchrotron radiation has advantages over conventional x rays in that its source brightness is a thousand times greater throughout a continuous energy spectrum, and resonances are produced with specific electron energy levels. Two major synchrotron radiation sources are operated by DOE: the Stanford Synchrotron Radiation Laboratory at SLAC, and the National Synchrotron Light Source at Brookhaven

Synchrotron radiation

International Nuclear Information System (INIS)

Hallmeier, K.H.; Meisel, A.; Ranft, J.

1982-01-01

The physical background and the properties of synchrotron radiation are described. The radiation offers many useful applications in the fields of spectroscopy and structural investigations. Some examples are given

Radiation-induced thermoacoustic imaging

International Nuclear Information System (INIS)

Bowen, T.

1984-01-01

This invention provides a new technique for obtaining information non-invasively on the composition and structures of a material or body by detecting radiation-induced thermoacoustic image features. This is accomplished by utilizing the acoustic wave generated by sudden thermal stress. The sudden thermal stress is induced by a pulse of radiation which deposits energy causing a rapid, but very small, rise of temperature (typically, ΔT approximately 10sup(-6) - 10sup(-5) deg C). The radiation may be ionizing radiation, such as high energy electrons, photons (x-rays), neutrons, or other charged particles or it may be non-ionizing radiation, such as R.F. and microwave electromagnetic radiation and ultrasonic radiation. The choice of radiation depends on the nature of the body to be imaged and the type of information desired

Apparatus for minimizing radiation exposure and improving resolution in radiation imaging devices

International Nuclear Information System (INIS)

Ashe, J.B.; Williams, G.H.; Sypal, K.L.

1978-01-01

A collimator is disclosed for minimizing radiation exposure and improving resolution in radiation imaging devices. The collimator provides a penetrating beam of radiation from a source thereof, which beam is substantially non-diverging in at least one direction. In the preferred embodiment, the collimator comprises an elongated sandwich assembly of a plurality of layers of material exhibiting relatively high radiation attenuation characteristics, which attenuating layers are spaced apart and separated from one another by interleaved layers of material exhibiting relatively low radiation attenuation characteristics. The sandwich assembly is adapted for lengthwise disposition and orientation between a radiation source and a target or receiver such that the attenuating layers are parallel to the desired direction of the beam with the interleaved spacing layers providing direct paths for the radiation

Acute Radiation Effects Resulting from Exposure to Solar Particle Event-Like Radiation

Science.gov (United States)

Kennedy, Ann; Cengel, Keith

2012-07-01

A major solar particle event (SPE) may place astronauts at significant risk for the acute radiation syndrome (ARS), which may be exacerbated when combined with other space flight stressors, such that the mission or crew health may be compromised. The National Space Biomedical Research Institute (NSBRI) Center of Acute Radiation Research (CARR) is focused on the assessment of risks of adverse biological effects related to the ARS in animal models exposed to space flight stressors combined with the types of radiation expected during an SPE. As part of this program, FDA-approved drugs that may prevent and/or mitigate ARS symptoms are being evaluated. The CARR studies are focused on the adverse biological effects resulting from exposure to the types of radiation, at the appropriate energies, doses and dose-rates, present during an SPE (and standard reference radiations, gamma rays or electrons). The ARS is a phased syndrome which often includes vomiting and fatigue. Other acute adverse biologic effects of concern are the loss of hematopoietic cells, which can result in compromised bone marrow and immune cell functions. There is also concern for skin damage from high SPE radiation doses, including burns, and resulting immune system dysfunction. Using 3 separate animal model systems (ferrets, mice and pigs), the major ARS biologic endpoints being evaluated are: 1) vomiting/retching and fatigue, 2) hematologic changes (with focus on white blood cells) and immune system changes resulting from exposure to SPE radiation with and without reduced weightbearing conditions, and 3) skin injury and related immune system functions. In all of these areas of research, statistically significant adverse health effects have been observed in animals exposed to SPE-like radiation. Countermeasures for the management of ARS symptoms are being evaluated. New research findings from the past grant year will be discussed. Acknowledgements: This research is supported by the NSBRI Center of Acute

Radiation distribution sensor with optical fibers for high radiation fields

International Nuclear Information System (INIS)

Takada, Eiji; Kimura, Atsushi; Hosono, Yoneichi; Takahashi, Hiroyuki; Nakazawa, Masaharu

1999-01-01

Radiation distribution sensors with their feasibilities have been described in earlier works. However, due to large radiation induced transmission losses in optical fibers, especially in the visible wavelength region, it has been difficult to apply these techniques to high radiation fields. In this study, we proposed a new concept of optical fiber based radiation distribution measurements with near infrared (IR) emission. Near IR scintillators were attached to the ends of optical fibers, where the fibers were bundled and connected to an N-MOS line sensor or a cooled CCD camera. From the measurements of each area density, the radiation levels at the positions of the scintillators can be known. The linearity between the gamma dose rate at each scintillator and the registered counts has been examined. For correcting the radiation induced loss effects, we applied the Optical Time Domain Reflectometry technique to measure the loss distribution and from the results, a possibility for correction of the loss effect has been demonstrated. The applicable dose rate range was evaluated to be from 0.1 to 10 3 Gy/h. This system can be a promising tool as a flexible dose rate distribution monitor in radiation facilities like nuclear plants and accelerator facilities. (author)

THE ROLE OF RADIATION ACCIDENTS AND INDUSTRIAL APPLICATIONS OF IONIZING RADIATION SOURCES IN THE PROBLEM OF RADIATION DAMAGE

OpenAIRE

Кіхтенко, Ігор Миколайович

2016-01-01

Subject of research – the relevance of radiation damage at modern development of industry and medicine. In the world of radiation sources used in different fields of practice and their application in the future will increase, which greatly increases the likelihood of injury in a significant contingent of people.Research topic – the definition of the role of nuclear energy and the industrial use of ionizing radiation sources in the problem of radiation damage. The purpose of research – identif...

Radiation Protection Ordinance. Preventive Radiation Protection Act. 3. rev. and enlarged ed.

International Nuclear Information System (INIS)

Kramer, R.; Zerlett, G.

1990-01-01

This 3rd edition presents the official explanations of the legislative intent behind the Radiation Protection Ordinance of 1976 and the 2nd amending ordinance, and the commentaries which as usual refer to the legal aspects and the related medical, scientific, and technical aspects. As a consequence of the reactor accident at Chernobyl, the existing radiation protection law has been extended by the Act for Preventive Measures for Pretection of the Population Against the Hazards of Ionizing Radiation (Preventive Radiation Protection Act), establishing preventive legal provisions and measures, so that this new edition has likewise been extended by commentaries on the Protective Radiation Protection Act and an introduction to the new area of law. The material also includes the Act for Establishment of a Federal Office for Radiation Protection, of October 9, 1989, which amended the Atomic Energy Act and the Preventive Radiation Protection Act. The correction of the Radiation Protection Ordinance of October 16, 1989 (BGBl. I p. 1926) has been incorporated into the text of the amended version of the Radiation Protection Ordinance. Court decisions and literature referred to cover material published up to the first months of 1989. (orig.) [de

XXX. Days of Radiation Protection. Conference Proceedings of the 30-th Days of Radiation Protection

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-11-15

The publication has been set up as a proceedings of the conference dealing with health protection during work with ionizing radiation for different activities which involve the handling of ionizing radiation sources. The main conference topics are focused on current problems in radiation protection and radioecology. In this proceedings totally 107 papers are published. The Conference consists of following sections: Effects of ionizing radiation; Regulation of radiation protection; Dosimetry and Metrology of ionizing radiation; Radiation protection in nuclear Power plants; Medical exposure and radiation protection in diagnostic radiology, nuclear medicine and radiation oncology; Natural radioactivity issues in radiation protection; Education, societal aspects and public involvement in radiation protection, trends and perspectives.

XXX. Days of Radiation Protection. Conference Proceedings of the 30-th Days of Radiation Protection

International Nuclear Information System (INIS)

2008-11-01

The publication has been set up as a proceedings of the conference dealing with health protection during work with ionizing radiation for different activities which involve the handling of ionizing radiation sources. The main conference topics are focused on current problems in radiation protection and radioecology. In this proceedings totally 107 papers are published. The Conference consists of following sections: Effects of ionizing radiation; Regulation of radiation protection; Dosimetry and Metrology of ionizing radiation; Radiation protection in nuclear Power plants; Medical exposure and radiation protection in diagnostic radiology, nuclear medicine and radiation oncology; Natural radioactivity issues in radiation protection; Education, societal aspects and public involvement in radiation protection, trends and perspectives

Hazards of cosmic radiation; Radiation cosmique: danger dans l'espace

Energy Technology Data Exchange (ETDEWEB)

Bonnet-Bidaud, J M; Dzitko, H

2000-06-01

The main limitations on long-distance space transport is neither the energy source nor the propulsion system but appears to be the protection of cosmonauts from radiation. Cosmic radiation is made up of protons (87%), alpha particles (12%) and heavy nuclei (1%), all these particles travel through interstellar space and come from the explosion of stars at the end of their life. The earth is protected from cosmic radiation by 3 natural shields: (i) the magnetic field generated by the solar wind, (ii) the earth magnetic field (magnetosphere), and (iii) the earth atmosphere, this elusive layer of air is equivalent to a 10 meter-high volume of water. Magnetosphere and atmosphere reduce the radiation dose by a factor 4000. According to a European directive (1996) air crews must be considered as radiation workers. (A.C.)

Strengthening the radiation protection culture: a priority of EDF radiation protection policy

International Nuclear Information System (INIS)

Garcier, Y.

2006-01-01

Full text of publication follows: In order to improve the management of radiation protection at EDF nuclear power plants, the Human Factors Group of the Research and Development Division of EDF has performed some studies on the appropriation process of the radiation protection requirements. These studies have notably shown that an efficient application of the radiation protection requirements lies on a comprehension by all workers of the meaning of these requirements. Furthermore, they should not be applied under the constraint or because of the fear of a sanction, but the workers need to perceive and understand the benefits in terms of protection associated with the radiation protection requirements. The strengthening of the radiation protection culture is therefore a key element of the radiation protection policy developed by EDF. This culture lies on an awareness of the health risks potentially associated with low levels of ionising radiations, as well as on the knowledge of tools, techniques and good practices developed to control the level of exposures and improve the radiation protection. Various type of actions have been undertaken to reinforce among the relevant players (exposed and non-exposed workers, contractors, all levels of management,... ) an awareness of radiation protection in order to integrate it in their day to day work: elaboration of a 'radiation protection system of reference' explaining how the radiation protection regulatory requirements are applied at EDF, publication of a 'radiation protection handbook' available for all workers (including contractors), training sessions, creation of networks of specialists from the various nuclear power plants on specific radiation protection issues, organisation of feed-back experience forum, etc. Beyond these specific actions, i t is also important to ensure a support and an assistance on the field by dedicated specialists. In this perspective, the health physicists have to play a key role in order to

Radiation hormesis: an outcome of exposure to low level ionizing radiation

International Nuclear Information System (INIS)

Kant, Krishan

2012-01-01

Ionizing radiation is a benign environmental agent at background levels. Human population is always exposed to ionizing radiation from natural sources. Important sources are cosmic rays which come from outer space and from the surface of the sun, terrestrial radionuclides which occur in the earths crust in various geological formations in soils, rocks, building materials, plants, water, food, air and in the human body itself. With the increasing use of radiation in health facilities, scientific research, industry and agriculture, the study of impact of low-level ionizing radiation on environment and possible health effects on future generations has been a cause of concern in recent years. As regards the effects, it is established fact that high doses of ionizing radiation are harmful to health, there exists, however, a substantial controversy regarding the effects of low doses of ionizing radiation (LLIR). In the present paper, brief review of the available literature, data and reports on stimulation by low-dose irradiation and recent data supporting radiation hormesis. A linear quadratic model has been given illustrating the validity of radiation hormesis, besides the comparison of the dose rates arising from natural and manmade sources to the Indian population. This overview summarizes various reports

Spacecraft radiator systems

Science.gov (United States)

Anderson, Grant A. (Inventor)

2012-01-01

A spacecraft radiator system designed to provide structural support to the spacecraft. Structural support is provided by the geometric "crescent" form of the panels of the spacecraft radiator. This integration of radiator and structural support provides spacecraft with a semi-monocoque design.

Radiation practices 1996

International Nuclear Information System (INIS)

Havukainen, R.

1997-05-01

At the end of 1996, there were 1,762 valid safety licences in Finland for the use of radiation. In addition, there were 2,052 responsible parties for dental x-ray diagnostics. The registry of the Finnish Centre for Radiation and Nuclear Safety listed 13,360 radiation sources and 313 radionuclide laboratories. The import of radioactive substances amounted to 1.14 x 10 +16 Bq and export to 7.78 x 10 +13 Bq. A total of 4.02 x 10 +13 Bq of short-lived radionuclides were produced in Finland. There were 11,842 workers monitored for radiation exposure at 1,352 work sites. Of these employees, 27% received an annual dose exceeding the recording level. The total dose recorded in the dose registry (sum of individual dosimeter readings) was 7.96 manSv in 1996, with nuclear power plant workers accounting for 69% of this total. The annual dosimeter reading of ten medical doctors (radiologists, interventional radiologists and cardiologists) and eight nuclear power plant employees was equal to or in excess of 20 mSv. Effective doses, however, did not exceed the dose limit of 50 mSv established for one-year monitoring periods. The sum of dosimeter readings (depth dose) on the lead-rubber apron of one interventional radiologist was 242 mSv. It was verified that the annual dose limit for the lens of the eye, 150 mSv, had been exceeded in this case. This high dose was caused by the fact that the radiologist had carried out multiple examinations where unusually high exposure to radiation was an unavoidable part of the task. Report was made of 12 incidents of anomalies in the use of radiation. None of these proved to have caused significant radiation exposure to the radiation source operators. Five of these cases occurred in radiotherapy, three in use of a radiation source in industry, three in transport of radiation sources and one in use of solarium appliances. Radiation-contaminated material was found in 17 shipments of scrap. (orig.)

Radiation practices 1996

Energy Technology Data Exchange (ETDEWEB)

Havukainen, R. [ed.

1997-05-01

At the end of 1996, there were 1,762 valid safety licences in Finland for the use of radiation. In addition, there were 2,052 responsible parties for dental x-ray diagnostics. The registry of the Finnish Centre for Radiation and Nuclear Safety listed 13,360 radiation sources and 313 radionuclide laboratories. The import of radioactive substances amounted to 1.14 x 10{sup +16} Bq and export to 7.78 x 10{sup +13} Bq. A total of 4.02 x 10{sup +13} Bq of short-lived radionuclides were produced in Finland. There were 11,842 workers monitored for radiation exposure at 1,352 work sites. Of these employees, 27% received an annual dose exceeding the recording level. The total dose recorded in the dose registry (sum of individual dosimeter readings) was 7.96 manSv in 1996, with nuclear power plant workers accounting for 69% of this total. The annual dosimeter reading of ten medical doctors (radiologists, interventional radiologists and cardiologists) and eight nuclear power plant employees was equal to or in excess of 20 mSv. Effective doses, however, did not exceed the dose limit of 50 mSv established for one-year monitoring periods. The sum of dosimeter readings (depth dose) on the lead-rubber apron of one interventional radiologist was 242 mSv. It was verified that the annual dose limit for the lens of the eye, 150 mSv, had been exceeded in this case. This high dose was caused by the fact that the radiologist had carried out multiple examinations where unusually high exposure to radiation was an unavoidable part of the task. Report was made of 12 incidents of anomalies in the use of radiation. None of these proved to have caused significant radiation exposure to the radiation source operators. Five of these cases occurred in radiotherapy, three in use of a radiation source in industry, three in transport of radiation sources and one in use of solarium appliances. Radiation-contaminated material was found in 17 shipments of scrap. (orig.)

Radiation protection zoning

International Nuclear Information System (INIS)

2015-01-01

Radiation being not visible, the zoning of an area containing radioactive sources is important in terms of safety. Concerning radiation protection, 2 work zones are defined by regulations: the monitored zone and the controlled zone. The ministerial order of 15 may 2006 settles the frontier between the 2 zones in terms of radiation dose rates, the rules for access and the safety standards in both zones. Radioprotection rules and the name of the person responsible for radiation protection must be displayed. The frontier between the 2 zones must be materialized and marked with adequate equipment (specific danger signs and tapes). Both zones are submitted to selective entrance, the access for the controlled zone is limited because of the radiation risk and of the necessity of confining radioactive contamination while the limitation of the access to the monitored zone is due to radiation risk only. (A.C.)

Canada: Living with radiation

International Nuclear Information System (INIS)

1995-01-01

Canadians are exposed daily to a variety of naturally occurring radiation. Heat and light from the sun, are familiar examples. Radium and uranium are naturally occurring materials which have been found to emit radiation and so have been called radioactive. There are also various types of artificially produced forms of radiation that are employed routinely in modern living, such as radio and television waves and microwaves. X-rays, another common type of radiation, are widely used in medicine as are some man-made radioactive substances. These emit radiation just like naturally occurring radioactive materials. Surveys have shown that many people have a poor understanding of the risks associated with the activities of modern living. Exposure to ionizing radiation from radioactive materials is also considered by many persons to have a high risk, This booklet attempts to inform the readers about ionizing radiation, its uses and the risks associated with it, and to put these risks in perspective with the risks of other activities and practices. A range of topics from medical uses of radiation to emergency planning, from biological effects of radiation to nuclear power, each topic is explained to relate radiation to our everyday lives. 44 figs

Canada: Living with radiation

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

Canadians are exposed daily to a variety of naturally occurring radiation. Heat and light from the sun, are familiar examples. Radium and uranium are naturally occurring materials which have been found to emit radiation and so have been called radioactive. There are also various types of artificially produced forms of radiation that are employed routinely in modern living, such as radio and television waves and microwaves. X-rays, another common type of radiation, are widely used in medicine as are some man-made radioactive substances. These emit radiation just like naturally occurring radioactive materials. Surveys have shown that many people have a poor understanding of the risks associated with the activities of modern living. Exposure to ionizing radiation from radioactive materials is also considered by many persons to have a high risk, This booklet attempts to inform the readers about ionizing radiation, its uses and the risks associated with it, and to put these risks in perspective with the risks of other activities and practices. A range of topics from medical uses of radiation to emergency planning, from biological effects of radiation to nuclear power, each topic is explained to relate radiation to our everyday lives. 44 figs.

Radiation protection training for users of ionizing radiation in Hungary

International Nuclear Information System (INIS)

Pellet, S.; Giczi, F.; Elek, R.; Temesi, A.; Csizmadia, H.; Sera, E.

2012-01-01

According to the current and previous regulation related to the safety use of ionizing radiation, the personnel involved must obtain special qualification in radiation protection. In Hungary the radiation protection training are performed by appropriately certified training centers on basic, advanced and comprehensive levels. Certification of the training centers is given by the competent radiological health/radiation protection authority. The office of the Chief Medical Officer is the certifying authority for advanced and comprehensive levels training, as well as competent Regional Radiological Health Authority is responsible for basic level courses. The content and length of courses are specified in the regulation for all three levels of industrial, laboratory and medical users, in general. Some of the universities, technical and medical oriented are certified for advanced training for students as gradual course. Recently in Hungary there are 47 certified training centers for advanced and comprehensive courses, where the trainers should have a five years job experience in radiation protection and successful completion of comprehensive level course in radiation protection. (authors)

Modification of genetic effects of gamma radiation by laser radiation

International Nuclear Information System (INIS)

Khotyljova, L.V.; Khokhlova, S.A.; Khokhlov, I.V.

1988-01-01

Full text: Mutants obtained by means of ionizing radiation and chemical mutagens often show low viability and productivity that makes their use in plant breeding difficult. Methods reducing the destructive mutagen action on important functions of plant organism and increasing quality and practical value of induced mutants would be interesting. We believe that one method for increasing efficiency of experimental mutagenesis in plants is the application of laser radiation as a modificator of genetic effects of ionizing radiation and chemical mutagens. Combined exposure of wheat seedlings to a gamma radiation dose of 2 kR and to laser radiation with the wave length of 632.8 nm (power density - 20 mVt/cm 2 , exposure - 30 min.) resulted in reducing the chromosomal aberration percentage from 30.5% in the gamma version to 16.3% in the combined treatment version. A radiosensibilizing effect was observed at additional exposure of gamma irradiated wheat seeds to laser light with the wave length of 441.6 nm where chromosomal aberration percentage increased from 22% in the gamma-irradiation version to 31% in the combined treatment version. By laser radiation it is also possible to normalize mitotic cell activity suppressed by gamma irradiation. Additional seedling irradiation with the light of helium-neon laser (632.8 nm) resulted in recovery of mitotic cell activity from 21% to 62% and increasing the average content of DNA per nucleus by 10%. The influence of only laser radiation on plant variability was also studied and it was shown that irradiation of wheat seeds and seedlings with pulsed and continuous laser light of visible spectrum resulted in phenotypically altered forms in M 2 . Their frequencies was dependent upon power density, dose and radiation wave length. Number of altered forms increased in going from long-wave to short-wave spectrum region. In comparing efficiency of different laser types of pulsed and continuous exposure (dose - 180 J/cm 2 ) 2% of altered

Radiation processing in Japan

Energy Technology Data Exchange (ETDEWEB)

Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2001-03-01

Economic scale of radiation application in the field of industry, agriculture and medicine in Japan in 1997 was investigated to compare its economic impacts with that of nuclear energy industry. Total production value of radiation application accounted for 54% of nuclear industry including nuclear energy industry and radiation applications in three fields above. Industrial radiation applications were further divided into five groups, namely nondestructive test, RI instruments, radiation facilities, radiation processing and ion beam processing. More than 70% of the total production value was brought about by ion beam processing for use with IC and semiconductors. Future economic prospect of radiation processing of polymers, for example cross-linking, EB curing, graft polymerization and degradation, is reviewed. Particular attention was paid to radiation vulcanization of natural rubber latex and also to degradation of natural polymers. (S. Ohno)

Radiation processing in Japan

International Nuclear Information System (INIS)

Makuuchi, Keizo

2001-01-01

Economic scale of radiation application in the field of industry, agriculture and medicine in Japan in 1997 was investigated to compare its economic impacts with that of nuclear energy industry. Total production value of radiation application accounted for 54% of nuclear industry including nuclear energy industry and radiation applications in three fields above. Industrial radiation applications were further divided into five groups, namely nondestructive test, RI instruments, radiation facilities, radiation processing and ion beam processing. More than 70% of the total production value was brought about by ion beam processing for use with IC and semiconductors. Future economic prospect of radiation processing of polymers, for example cross-linking, EB curing, graft polymerization and degradation, is reviewed. Particular attention was paid to radiation vulcanization of natural rubber latex and also to degradation of natural polymers. (S. Ohno)

Radiation safety of Takasaki ion accelerators for advanced radiation in JAERI

International Nuclear Information System (INIS)

Watanabe, Hiromasa; Tanaka, Susumu; Anazawa, Yutaka

1991-01-01

Building layout of Takasaki ion accelerator facility has been started since 1987, with the propulsion of research development of (1) cosmetic environment materials, (2) nuclear fusion reactors, (3) biotechnology, and (4) new functional materials. This paper deals with an AVF cyclotron and a tandem type accelerator, focusing on safety design, radiation safety management, and radioactive waste management. Safety design is discussed in view of radiation shielding and activation countermeasures. Radiation safety management covers radiation monitoring in the workplace, exhaust radioactivity, environment outside the facility, and the other equipments; personal monitoring; and protective management of exposure. For radiation waste management, basic concept and management methods are commented on. (N.K.)

The Integrated Radiation Mapper Assistant

Energy Technology Data Exchange (ETDEWEB)

Carlton, R.E.; Tripp, L.R. [Odetics, Inc., Anaheim, CA (United States)

1995-03-01

The Integrated Radiation Mapper Assistant (IRMA) system combines state-of-the-art radiation sensors and microprocessor based analysis techniques to perform radiation surveys. Control of the survey function is from a control station located outside the radiation thus reducing time spent in radiation areas performing radiation surveys. The system consists of a directional radiation sensor, a laser range finder, two area radiation sensors, and a video camera mounted on a pan and tilt platform. THis sensor package is deployable on a remotely operated vehicle. The outputs of the system are radiation intensity maps identifying both radiation source intensities and radiation levels throughout the room being surveyed. After completion of the survey, the data can be removed from the control station computer for further analysis or archiving.

Nuclear science in the 20th century. Radiation chemistry and radiation processing

International Nuclear Information System (INIS)

Fu Tao; Xu Furong; Zheng Chunkai

2003-01-01

The application of nuclear science and technology to chemistry has led to two important subjects, radiation chemistry and radiation processing, which are playing important roles in many aspects of science and society. We review the development and major applications of radiation chemistry and radiation processing, including the basic physical and chemical mechanisms involved

Training in radiation protection

International Nuclear Information System (INIS)

Schreiber, F.

1998-01-01

Persons who are exposed to ionizing radiation at their workplace have to be trained in radiation protection. According to the Radiation Protection Ordinance the person with responsibility in radiation protection has to guarantee that the training is performed twice a year. Our training material was created especially for the persons defined in the Radiation Protection Ordinance and the X-ray Ordinance. It enables persons who teach (generally the radiation protection officer) to perform the training without tedious study and preparation of the documents. Our material is not just another textbook for radiation protection but rather a folder with colour transparencies and explanatory texts which make a difference in volume and price in comparison to other existing materials. (orig.) [de

Occupational radiation exposure in Germany in 2006. Report of the radiation protection register