WorldWideScience

Sample records for net radiation absorbed

  1. Estimation of absorbed photosynthetically active radiation and vegetation net production efficiency using satellite data

    International Nuclear Information System (INIS)

    Hanan, N.P.; Prince, S.D.; Begue, A.

    1995-01-01

    The amount of photosynthetically active radiation (PAR) absorbed by green vegetation is an important determinant of photosynthesis and growth. Methods for the estimation of fractional absorption of PAR (iff PAR ) for areas greater than 1 km 2 using satellite data are discussed, and are applied to sites in the Sahel that have a sparse herb layer and tree cover of less than 5%. Using harvest measurements of seasonal net production, net production efficiencies are calculated. Variation in estimates of seasonal PAR absorption (APAR) caused by the atmospheric correction method and relationship between surface reflectances and iff PAR is considered. The use of maximum value composites of satellite NDVI to reduce the effect of the atmosphere is shown to produce inaccurate APAR estimates. In this data set, however, atmospheric correction using average optical depths was found to give good approximations of the fully corrected data. A simulation of canopy radiative transfer using the SAIL model was used to derive a relationship between canopy NDVI and iff PAR . Seasonal APAR estimates assuming a 1:1 relationship between iff PAR and NDVI overestimated the SAIL modeled results by up to 260%. The use of a modified 1:1 relationship, where iff PAR was assumed to be linearly related to NDVI scaled between minimum (soil) and maximum (infinite canopy) values, underestimated the SAIL modeled results by up to 35%. Estimated net production efficiencies (ϵ n , dry matter per unit APAR) fell in the range 0.12–1.61 g MJ −1 for above ground production, and in the range 0.16–1.88 g MJ −1 for total production. Sites with lower rainfall had reduced efficiencies, probably caused by physiological constraints on photosynthesis during dry conditions. (author)

  2. HYPERION NET - a distributed measurement system for monitoring background ionizing radiation

    International Nuclear Information System (INIS)

    Saponjic, Dj.; Zigic, A.; Arandjelovic, V.

    2003-01-01

    The distributed measurement system - HYPERION NET, based on the concept of FieldBus technology, has been developed, implemented, and tested as a pilot project, the first WEB enabled on-line networked ionizing radiation monitoring and measurement system. The Net has layered the structure, tree topology, and is based on the Internet infrastructure and TCP/IP communication protocol. The Net's core element is an intelligent GM transmitter, based on GM tube, used for measuring the absorbed dose in air, in the range of 0.087 to 720 μGy/h. The transmitter makes use of an advanced count rate measurement algorithm capable of suppressing the statistical fluctuations of the measured quantity, which significantly improves its measurement performance mailing it suitable for environmental radiation measurements. (author)

  3. Absorber for terahertz radiation management

    Science.gov (United States)

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  4. Photosynthesis, growth, and ultraviolet irradiance absorbance of Cucurbita pepo L. leaves exposed to ultraviolet-B radiation (280 to 315 nm)

    International Nuclear Information System (INIS)

    Sisson, W.B.

    1981-01-01

    Net photosynthesis, growth, and ultraviolet (uv) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of uv-B irradiation and a uv-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other uv-B radiation-absorbing compounds from the first leaves increased with time and level of uv-B radiation impinging on leaf surfaces. Although absorbance of uv-B radiation by extracted pigments increased substantially, uv-B radiation attenuation apparently was insufficient to protect completely the photosynthetic apparatus or leaf growth processes. Leaf expansion was repressed by daily exposure to 1365 Joules per meter per day of biologically effective uv-B radiation by not by exposure to 660 Joules per meter per day. Photosynthesis measured through ontogenesis of the first leaf was depressed by both uv-B radiation treatments. Repression of photosynthesis by uv-B radiation was especially evident during the ontogenetic period of maximum photosynthetic activity

  5. Dynamics of nonpersistent aphid-borne viruses in lettuce crops covered with UV-absorbing nets.

    Science.gov (United States)

    Legarrea, S; Betancourt, M; Plaza, M; Fraile, A; García-Arenal, F; Fereres, A

    2012-04-01

    Aphid-transmitted viruses frequently cause severe epidemics in lettuce grown under Mediterranean climates. Spatio-temporal dynamics of aphid-transmitted viruses and its vector were studied on lettuce (Lactuca sativa L.) grown under tunnels covered by two types of nets: a commercial UV-absorbing net (Bionet) and a Standard net. A group of plants infected by Cucumber mosaic virus (CMV, family Bromoviridae, genus Cucumovirus) and Lettuce mosaic virus (LMV, family Potyviridae, genus Potyvirus) was transplanted in each plot. The same virus-infected source plants were artificially infested by the aphid Macrosiphum euphorbiae (Thomas). Secondary spread of insects was weekly monitored and plants were sampled for the detection of viruses every two weeks. In 2008, the infection rate of both CMV and LMV were lower under the Bionet than under the Standard cover, probably due to the lower population density and lower dispersal rate achieved by M. euphorbiae. However, during spring of 2009, significant differences in the rate of infection between the two covers were only found for LMV six weeks after transplant. The spatial distribution of the viruses analysed by SADIE methodology was "at random", and it was not associated to the spatial pattern of the vector. The results obtained are discussed analyzing the wide range of interactions that occurred among UV-radiation, host plant, viruses, insect vector and environmental conditions. Our results show that UV-absorbing nets can be recommended as a component of an integrated disease management program to reduce secondary spread of lettuce viruses, although not as a control measure on its own. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Design and development of radiation absorber for sighting beam line

    International Nuclear Information System (INIS)

    Sridhar, R.; Shukla, S.K.

    2005-01-01

    During the commissioning of Indus-2 , it is necessary to view the synchrotron radiation that will be emanating from the dipole exit ports. The 10 0 beam line from dipole 11 was earmarked for sighting beam line. The synchrotron radiation power density would be around 340 watts on the photon absorber inside the radiation absorber module, at the specified beam power of Indus-2. The beam striking on this photon absorber produces x-rays and Bremsstrahlung radiation. These are to be stopped and absorbed by radiation absorber. The photon absorber and the radiation absorber are integrated in a single vacuum chamber and actuated by a pneumatic cylinder connected using a bellow. Radiation absorber was needed to isolate the diagnostic components and to protect them from radiation a well as heat when they were not in use. The paper describes the design, calculation and development of the dynamic photon cum radiation absorber. The ultimate vacuum performance is also described. (author)

  7. Refining surface net radiation estimates in arid and semi-arid climates of Iran

    Science.gov (United States)

    Golkar, Foroogh; Rossow, William B.; Sabziparvar, Ali Akbar

    2018-06-01

    Although the downwelling fluxes exhibit space-time scales of dependency on characteristic of atmospheric variations, especially clouds, the upward fluxes and, hence the net radiation, depends on the variation of surface properties, particularly surface skin temperature and albedo. Evapotranspiration at the land surface depends on the properties of that surface and is determined primarily by the net surface radiation, mostly absorbed solar radiation. Thus, relatively high spatial resolution net radiation data are needed for evapotranspiration studies. Moreover, in more arid environments, the diurnal variations of surface (air and skin) temperature can be large so relatively high (sub-daily) time resolution net radiation is also needed. There are a variety of radiation and surface property products available but they differ in accuracy, space-time resolution and information content. This situation motivated the current study to evaluate multiple sources of information to obtain the best net radiation estimate with the highest space-time resolution from ISCCP FD dataset. This study investigates the accuracy of the ISCCP FD and AIRS surface air and skin temperatures, as well as the ISCCP FD and MODIS surface albedos and aerosol optical depths as the leading source of uncertainty in ISCCP FD dataset. The surface air temperatures, 10-cm soil temperatures and surface solar insolation from a number of surface sites are used to judge the best combinations of data products, especially on clear days. The corresponding surface skin temperatures in ISCCP FD, although they are known to be biased somewhat high, disagreed more with AIRS measurements because of the mismatch of spatial resolutions. The effect of spatial resolution on the comparisons was confirmed using the even higher resolution MODIS surface skin temperature values. The agreement of ISCCP FD surface solar insolation with surface measurements is good (within 2.4-9.1%), but the use of MODIS aerosol optical depths as

  8. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary goal is to build and test a rigid Lithium Chloride Absorber Radiator (LCAR) coupon based on honeycomb geometry that would be applicable for EVA and...

  9. Global Surface Net-Radiation at 5 km from MODIS Terra

    Directory of Open Access Journals (Sweden)

    Manish Verma

    2016-09-01

    Full Text Available Reliable and fine resolution estimates of surface net-radiation are required for estimating latent and sensible heat fluxes between the land surface and the atmosphere. However, currently, fine resolution estimates of net-radiation are not available and consequently it is challenging to develop multi-year estimates of evapotranspiration at scales that can capture land surface heterogeneity and are relevant for policy and decision-making. We developed and evaluated a global net-radiation product at 5 km and 8-day resolution by combining mutually consistent atmosphere and land data from the Moderate Resolution Imaging Spectroradiometer (MODIS on board Terra. Comparison with net-radiation measurements from 154 globally distributed sites (414 site-years from the FLUXNET and Surface Radiation budget network (SURFRAD showed that the net-radiation product agreed well with measurements across seasons and climate types in the extratropics (Wilmott’s index ranged from 0.74 for boreal to 0.63 for Mediterranean sites. Mean absolute deviation between the MODIS and measured net-radiation ranged from 38.0 ± 1.8 W∙m−2 in boreal to 72.0 ± 4.1 W∙m−2 in the tropical climates. The mean bias was small and constituted only 11%, 0.7%, 8.4%, 4.2%, 13.3%, and 5.4% of the mean absolute error in daytime net-radiation in boreal, Mediterranean, temperate-continental, temperate, semi-arid, and tropical climate, respectively. To assess the accuracy of the broader spatiotemporal patterns, we upscaled error-quantified MODIS net-radiation and compared it with the net-radiation estimates from the coarse spatial (1° × 1° but high temporal resolution gridded net-radiation product from the Clouds and Earth’s Radiant Energy System (CERES. Our estimates agreed closely with the net-radiation estimates from the CERES. Difference between the two was less than 10 W·m−2 in 94% of the total land area. MODIS net-radiation product will be a valuable resource for the

  10. Comparison of the performance of net radiation calculation models

    DEFF Research Database (Denmark)

    Kjærsgaard, Jeppe Hvelplund; Cuenca, R.H.; Martinez-Cob, A.

    2009-01-01

    . The long-wave radiation models included a physically based model, an empirical model from the literature, and a new empirical model. Both empirical models used only solar radiation as required for meteorological input. The long-wave radiation models were used with model calibration coefficients from......Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily...... values of net radiation were calculated using three net outgoing long-wave radiation models and compared to measured values. Four meteorological datasets representing two climate regimes, a sub-humid, high-latitude environment and a semi-arid mid-latitude environment, were used to test the models...

  11. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  12. Data error effects on net radiation and evapotranspiration estimation

    International Nuclear Information System (INIS)

    Llasat, M.C.; Snyder, R.L.

    1998-01-01

    The objective of this paper is to evaluate the potential error in estimating the net radiation and reference evapotranspiration resulting from errors in the measurement or estimation of weather parameters. A methodology for estimating the net radiation using hourly weather variables measured at a typical agrometeorological station (e.g., solar radiation, temperature and relative humidity) is presented. Then the error propagation analysis is made for net radiation and for reference evapotranspiration. Data from the Raimat weather station, which is located in the Catalonia region of Spain, are used to illustrate the error relationships. The results show that temperature, relative humidity and cloud cover errors have little effect on the net radiation or reference evapotranspiration. A 5°C error in estimating surface temperature leads to errors as big as 30 W m −2 at high temperature. A 4% solar radiation (R s ) error can cause a net radiation error as big as 26 W m −2 when R s ≈ 1000 W m −2 . However, the error is less when cloud cover is calculated as a function of the solar radiation. The absolute error in reference evapotranspiration (ET o ) equals the product of the net radiation error and the radiation term weighting factor [W = Δ(Δ1+γ)] in the ET o equation. Therefore, the ET o error varies between 65 and 85% of the R n error as air temperature increases from about 20° to 40°C. (author)

  13. Errors in measuring absorbed radiation and computing crop radiation use efficiency

    International Nuclear Information System (INIS)

    Gallo, K.P.; Daughtry, C.S.T.; Wiegand, C.L.

    1993-01-01

    Radiation use efficiency (RUE) is often a crucial component of crop growth models that relate dry matter production to energy received by the crop. RUE is a ratio that has units g J -1 , if defined as phytomass per unit of energy received, and units J J -1 , if defined as the energy content of phytomass per unit of energy received. Both the numerator and denominator in computation of RUE can vary with experimental assumptions and methodologies. The objectives of this study were to examine the effect that different methods of measuring the numerator and denominator have on the RUE of corn (Zea mays L.) and to illustrate this variation with experimental data. Computational methods examined included (i) direct measurements of the fraction of photosynthetically active radiation absorbed (f A ), (ii) estimates of f A derived from leaf area index (LAI), and (iii) estimates of f A derived from spectral vegetation indices. Direct measurements of absorbed PAR from planting to physiological maturity of corn were consistently greater than the indirect estimates based on green LAI or the spectral vegetation indices. Consequently, the RUE calculated using directly measured absorbed PAR was lower than the RUE calculated using the indirect measures of absorbed PAR. For crops that contain senesced vegetation, green LAI and the spectral vegetation indices provide appropriate estimates of the fraction of PAR absorbed by a crop canopy and, thus, accurate estimates of crop radiation use efficiency

  14. The effect of Arctic sea-ice extent on the absorbed (net solar flux at the surface, based on ISCCP-D2 cloud data for 1983–2007

    Directory of Open Access Journals (Sweden)

    C. Matsoukas

    2010-01-01

    Full Text Available We estimate the effect of the Arctic sea ice on the absorbed (net solar flux using a radiative transfer model. Ice and cloud input data to the model come from satellite observations, processed by the International Satellite Cloud Climatology Project (ISCCP and span the period July 1983–June 2007. The sea-ice effect on the solar radiation fluctuates seasonally with the solar flux and decreases interannually in synchronisation with the decreasing sea-ice extent. A disappearance of the Arctic ice cap during the sunlit period of the year would radically reduce the local albedo and cause an annually averaged 19.7 W m−2 increase in absorbed solar flux at the Arctic Ocean surface, or equivalently an annually averaged 0.55 W m−2 increase on the planetary scale. In the clear-sky scenario these numbers increase to 34.9 and 0.97 W m−2, respectively. A meltdown only in September, with all other months unaffected, increases the Arctic annually averaged solar absorption by 0.32 W m−2. We examined the net solar flux trends for the Arctic Ocean and found that the areas absorbing the solar flux more rapidly are the North Chukchi and Kara Seas, Baffin and Hudson Bays, and Davis Strait. The sensitivity of the Arctic absorbed solar flux on sea-ice extent and cloud amount was assessed. Although sea ice and cloud affect jointly the solar flux, we found little evidence of strong non-linearities.

  15. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  16. Absorbed energy for radiation crosslinking in stabilized PE systems

    International Nuclear Information System (INIS)

    Novakovic, Lj.; Gal, O.; Charlesby, A.

    1990-01-01

    A quantitative consideration on the absorbed energy consumption in various γ-irradiated polyethylene systems is given. On the base of the increased gel dose values for the PE systems containing antioxidant, relative to the gel doses for the pure polymers, the surplus of the absorbed energy due to the presence of the particular antioxidant is calculated. The increasing of the energy consumption in the stabilized systems depends on both the type and the content of the basic polymer. The surplus in the absorbed energy decreases with the radiation dose increasing, reflecting both the diminishing of the antioxidant concentration in the irradiating PE systems and the crosslinking level. The findings can be of interest in the estimation of the absorbed doses for the specific radiation crosslinking processes. (author)

  17. Absorbed energy for radiation crosslinking in stabilized PE systems

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, Lj; Gal, O [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia); Charlesby, A

    1990-01-01

    A quantitative consideration on the absorbed energy consumption in various {gamma}-irradiated polyethylene systems is given. On the base of the increased gel dose values for the PE systems containing antioxidant, relative to the gel doses for the pure polymers, the surplus of the absorbed energy due to the presence of the particular antioxidant is calculated. The increasing of the energy consumption in the stabilized systems depends on both the type and the content of the basic polymer. The surplus in the absorbed energy decreases with the radiation dose increasing, reflecting both the diminishing of the antioxidant concentration in the irradiating PE systems and the crosslinking level. The findings can be of interest in the estimation of the absorbed doses for the specific radiation crosslinking processes. (author).

  18. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

  19. Diminished UV-absorbing nets reduce the Spreads and population density of Macrosiphum euphorbiae in lettuce.

    OpenAIRE

    Legarrea, S.; Díaz, B. M.; Plaza, M.; Barrios, L.; Morales, Ignacio; Viñuela Sandoval, Elisa; Fereres Castiel, Alberto

    2012-01-01

    UV-absorbing covers reduce the incidence of injurious insect pests and viruses in protected crops. In the present study, the effect of a UV-absorbing net (Bionet) on the spatio-temporal dynamics of the potato aphid on lettuce plants was evaluated. A field experiment was conducted during three seasons in two identical tunnels divided in four plots. A set of lettuce plants were artificially infested with Macrosiphum euphorbiae adults and the population was estimated by counting aphids on ev...

  20. Visual indicator of absorbed radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Generalova, V V; Krasovitskii, B M; Vainshtok, B A; Gurskii, M N

    1968-10-15

    A visual indicator of the absorbed doses of ionizing radiation is proposed. The indicator has a polymer base with the addition of a dye. A distinctive feature of the indicator consists of the use of polystyrene as its polymer base with the addition of halogen-containing hydrocarbon and the light-proof dye. Such combination of the radiation-resistant polymer of polystyrene and the light-proof dyestuff makes the proposed indicator highly stable.

  1. An international intercomparison of absorbed dose measurements for radiation therapy

    International Nuclear Information System (INIS)

    Taiman Kadni; Noriah Mod Ali

    2002-01-01

    Dose intercomparison on an international basis has become an important component of quality assurance measurement i.e. to check the performance of absorbed dose measurements in radiation therapy. The absorbed dose to water measurements for radiation therapy at the SSDL, MINT have been regularly compared through international intercomparison programmes organised by the IAEA Dosimetry Laboratory, Seibersdorf, Austria such as IAEA/WHO TLD postal dose quality audits and the Intercomparison of therapy level ionisation chamber calibration factors in terms of air kerma and absorbed dose to water calibration factors. The results of these intercomparison in terms of percentage deviations for Cobalt 60 gamma radiation and megavoltage x-ray from medical linear accelerators participated by the SSDL-MINT during the year 1985-2001 are within the acceptance limit. (Author)

  2. Effect of the Absorbed Photosynthetically Active Radiation Estimation Error on Net Primary Production Estimation - A Study with MODIS FPAR and TOMS Ultraviolet Reflective Products

    International Nuclear Information System (INIS)

    Kobayashi, H.; Matsunaga, T.; Hoyano, A.

    2002-01-01

    Absorbed photosynthetically active radiation (APAR), which is defined as downward solar radiation in 400-700 nm absorbed by vegetation, is one of the significant variables for Net Primary Production (NPP) estimation from satellite data. Toward the reduction of the uncertainties in the global NPP estimation, it is necessary to clarify the APAR accuracy. In this paper, first we proposed the improved PAR estimation method based on Eck and Dye's method in which the ultraviolet (UV) reflectivity data derived from Total Ozone Mapping Spectrometer (TOMS) at the top of atmosphere were used for clouds transmittance estimation. The proposed method considered the variable effects of land surface UV reflectivity on the satellite-observed UV data. Monthly mean PAR comparisons between satellite-derived and ground-based data at various meteorological stations in Japan indicated that the improved PAR estimation method reduced the bias errors in the summer season. Assuming the relative error of the fraction of PAR (FPAR) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) to be 10%, we estimated APAR relative errors to be 10-15%. Annual NPP is calculated using APAR derived from MODIS/ FPAR and the improved PAR estimation method. It is shown that random and bias errors of annual NPP in a 1 km resolution pixel are less than 4% and 6% respectively. The APAR bias errors due to the PAR bias errors also affect the estimated total NPP. We estimated the most probable total annual NPP in Japan by subtracting the bias PAR errors. It amounts about 248 MtC/yr. Using the improved PAR estimation method, and Eck and Dye's method, total annual NPP is 4% and 9% difference from most probable value respectively. The previous intercomparison study among using fifteen NPP models4) showed that global NPP estimations among NPP models are 44.4-66.3 GtC/yr (coefficient of variation = 14%). Hence we conclude that the NPP estimation uncertainty due to APAR estimation error is small

  3. Advances in absorbed dose measurement standards at the australian radiation laboratory

    International Nuclear Information System (INIS)

    Boas, J.F.; Hargrave, N.J.; Huntley, R.B.; Kotler, L.H.; Webb, D.V.; Wise, K.N.

    1996-01-01

    The applications of ionising radiation in the medical and industrial fields require both an accurate knowledge of the amount of ionising radiation absorbed by the medium in question and the capability of relating this to National and International standards. The most useful measure of the amount of radiation is the absorbed dose which is defined as the energy absorbed per unit mass. For radiotherapy, the reference medium is water, even though the measurement of the absorbed dose to water is not straightforward. Two methods are commonly used to provide calibrations in absorbed dose to water. The first is the calibration of the chamber in terms of exposure in a Cobalt-60 beam, followed by the conversion by a protocol into dose to water in this and higher energy beams. The other route is via the use of a graphite calorimeter as a primary standard device, where the conversion from absorbed dose to graphite to absorbed dose in water is performed either by theoretical means making use of cavity ionisation theory, or by experiment where the graphite calorimeter and secondary standard ionisation chamber are placed at scaled distances from the source of the radiation beam (known as the Dose-Ratio method). Extensive measurements have been made at Cobalt-60 at ARL using both the exposure and absorbed dose to graphite routes. Agreement between the ARL measurements and those based on standards maintained by ANSTO and NPL is within ± 0.3%. Absorbed dose measurements have also been performed at ARL with photon beams of nominal energy 16 and 19 MeV obtained from the ARL linac. The validity of the protocols at high photon energies, the validity of the methods used to convert from absorbed dose in graphite to absorbed dose in water and the validity of the indices used to specify the beams are discussed. Brief mention will also be made of the establishment of a calibration facility for neutron monitors at ARL and of progress in the development of ERP dosimetry

  4. Advances in absorbed dose measurement standards at the australian radiation laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boas, J.F.; Hargrave, N.J.; Huntley, R.B.; Kotler, L.H.; Webb, D.V.; Wise, K.N. [Australian Radiation Laboratory, Yallambie, VIC (Australia)

    1996-12-31

    The applications of ionising radiation in the medical and industrial fields require both an accurate knowledge of the amount of ionising radiation absorbed by the medium in question and the capability of relating this to National and International standards. The most useful measure of the amount of radiation is the absorbed dose which is defined as the energy absorbed per unit mass. For radiotherapy, the reference medium is water, even though the measurement of the absorbed dose to water is not straightforward. Two methods are commonly used to provide calibrations in absorbed dose to water. The first is the calibration of the chamber in terms of exposure in a Cobalt-60 beam, followed by the conversion by a protocol into dose to water in this and higher energy beams. The other route is via the use of a graphite calorimeter as a primary standard device, where the conversion from absorbed dose to graphite to absorbed dose in water is performed either by theoretical means making use of cavity ionisation theory, or by experiment where the graphite calorimeter and secondary standard ionisation chamber are placed at scaled distances from the source of the radiation beam (known as the Dose-Ratio method). Extensive measurements have been made at Cobalt-60 at ARL using both the exposure and absorbed dose to graphite routes. Agreement between the ARL measurements and those based on standards maintained by ANSTO and NPL is within {+-} 0.3%. Absorbed dose measurements have also been performed at ARL with photon beams of nominal energy 16 and 19 MeV obtained from the ARL linac. The validity of the protocols at high photon energies, the validity of the methods used to convert from absorbed dose in graphite to absorbed dose in water and the validity of the indices used to specify the beams are discussed. Brief mention will also be made of the establishment of a calibration facility for neutron monitors at ARL and of progress in the development of ERP dosimetry.

  5. On the radiative effects of light-absorbing impurities on snowpack evolution

    Science.gov (United States)

    Dumont, M.; Tuzet, F.; Lafaysse, M.; Arnaud, L.; Picard, G.; Lejeune, Y.; Lamare, M.; Morin, S.; Voisin, D.; Di Mauro, B.

    2017-12-01

    The presence of light absorbing impurities in snow strongly decreases snow reflectance leading to an increase in the amount of solar energy absorbed by the snowpack. This effect is also known as impurities direct radiative effect. The change in the amount of energy absorbed by the snowpack modifies the temperature profile inside the snowpack and in turn snow metamorphism (impurities indirect radiative effects). In this work, we used the detailed snowpack model SURFEX/ISBA-Crocus with an explicit representation of snow light-absorbing impurities content (Tuzet et al., 2017) fed by medium-resolution ALADIN-Climate atmospheric model to represent dust and black carbon atmospheric deposition fluxes. The model is used at two sites: Col de Porte (medium elevation site in the French Alps) and Torgnon (high elevation site in the Italian Alps). The simulations are compared to in-situ observations and used to quantify the effects of light-absorbing impurities on snow melt rate and timing. The respective parts of the direct and indirect radiative effects of light-absorbing impurities in snow are also computed for the two sites, emphasizing the need to account for the interactions between snow metamorphism and LAI radiative properties, to accurately predict the effects of light-absorbing impurities in snow. Moreover, we describe how automated hyperspectral reflectance can be used to estimate effective impurities surface content in snow. Finally we demonstrate how these reflectances measurements either from in situ or satellite data can be used via an assimilation scheme to constrain snowpack ensemble simulations and better predict the snowpack state and evolution.

  6. Estimation of daily net radiation from synoptic meteorological data

    International Nuclear Information System (INIS)

    Lee, B.W.; Myung, E.J.; Kim, B.C.

    1991-01-01

    Five models for net radiation estimation reported by Linacre (1968), Berljand(1956), Nakayama et al. (1983), Chang (1970) and Doorenbos et al. (1977) were tested for the adaptability to Korea. A new model with effective longwave radiation term parameterized by air temperature, solar radiation and vapor pressure was formulated and tested for its accuracy. Above five models with original parameter values showed large absolute mean deviations ranging from 0.86 to 1.64 MJ/m 2 /day. The parameters of the above five models were reestimated by using net radiation and meteorological elements measured in Suwon, Korea

  7. RadNet: Open network protocol for radiation data

    International Nuclear Information System (INIS)

    Rees, B.; Olson, K.; Beckes-Talcott, J.; Kadner, S.; Wenderlich, T.; Hoy, M.; Doyle, W.; Koskelo, M.

    1998-01-01

    Safeguards instrumentation is increasingly being incorporated into remote monitoring applications. In the past, vendors of radiation monitoring instruments typically provided the tools for uploading the monitoring data to a host. However, the proprietary nature of communication protocols lends itself to increased computer support needs and increased installation expenses. As a result, a working group of suppliers and customers of radiation monitoring instruments defined an open network protocol for transferring packets on a local area network from radiation monitoring equipment to network hosts. The protocol was termed RadNet. While it is now primarily used for health physics instruments, RadNet's flexibility and strength make it ideal for remote monitoring of nuclear materials. The incorporation of standard, open protocols ensures that future work will not render present work obsolete; because RadNet utilizes standard Internet protocols, and is itself a non-proprietary standard. The use of industry standards also simplifies the development and implementation of ancillary services, e.g. E-main generation or even pager systems

  8. The influence of surface type on the absorbed radiation by a human under hot, dry conditions

    Science.gov (United States)

    Hardin, A. W.; Vanos, J. K.

    2018-01-01

    Given the predominant use of heat-retaining materials in urban areas, numerous studies have addressed the urban heat island mitigation potential of various "cool" options, such as vegetation and high-albedo surfaces. The influence of altered radiational properties of such surfaces affects not only the air temperature within a microclimate, but more importantly the interactions of long- and short-wave radiation fluxes with the human body. Minimal studies have assessed how cool surfaces affect thermal comfort via changes in absorbed radiation by a human ( R abs) using real-world, rather than modeled, urban field data. The purpose of the current study is to assess the changes in the absorbed radiation by a human—a critical component of human energy budget models—based on surface type on hot summer days (air temperatures > 38.5∘C). Field tests were conducted using a high-end microclimate station under predominantly clear sky conditions over ten surfaces with higher sky view factors in Lubbock, Texas. Three methods were used to measure and estimate R abs: a cylindrical radiation thermometer (CRT), a net radiometer, and a theoretical estimation model. Results over dry surfaces suggest that the use of high-albedo surfaces to reduce overall urban heat gain may not improve acute human thermal comfort in clear conditions due to increased reflected radiation. Further, the use of low-cost instrumentation, such as the CRT, shows potential in quantifying radiative heat loads within urban areas at temporal scales of 5-10 min or greater, yet further research is needed. Fine-scale radiative information in urban areas can aid in the decision-making process for urban heat mitigation using non-vegetated urban surfaces, with surface type choice is dependent on the need for short-term thermal comfort, or reducing cumulative heat gain to the urban fabric.

  9. Radiation absorbed dose estimate for rubidium-82 determined from in vivo measurements in human subjects

    International Nuclear Information System (INIS)

    Ryan, J. W.; Harper, P.V.; Stark, V.S.; Peterson, E.L.; Lathrop, K.A.

    1986-01-01

    Radiation absorbed doses from rubidium-82 injected intravenously were determined in two young men, aged 23 and 27, using a dynamic conjugate counting technique to provide data for the net organ integrated time-activity curves in five organs: kidneys, lungs, liver, heart, and testes. This technique utilized a tungsten collimated Anger camera and the accuracy was validated in a prestwood phantom. The data for each organ were compared with conjugate count rates of a reference Ge-68/Ga-68 standard which had been calibrated against the Rb-82 injected. The effects of attenuation in the body were eliminated. The MIRD method was used to calculate the organ self absorbed doses and the total organ absorbed doses. The mean total absorbed doses were as follows (mrads/mCi injected): kidneys 30.9, heart walls 7.5, lungs 6.0, liver 3.0, testes 2.0 (one subject only), red marrow 1.3, remainder of body 1.3 and, extrapolating to women, ovaries 1.2. This absorbed dose to the kidney is significantly less than the pessimistic estimate of 59.4 mrads/mCi, made assuming instantaneous uptake and complete extraction of activity with no excretion by the kidneys, which receive 20% of the cardiac output. Further, in a 68 year old man the renal self absorbed dose was approximately 40% less than the mean renal self absorbed dose of the younger men. This decrease is probably related to the decline in renal blood flow which occurs with advancing age but other factors may also contribute to the observed difference. 14 references, 4 figures, 2 tables

  10. RadNet (Environmental Radiation Ambient Monitoring System)

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet, formerly Environmental Radiation Ambient Monitoring System (ERAMS), is a national network of monitoring stations that regularly collect air, precipitation,...

  11. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  12. Problems in radiation absorbed dose estimation from positron emitters

    International Nuclear Information System (INIS)

    Powell, G.F.; Harper, P.V.; Reft, C.S.; Chen, C.T.; Lathrop, K.A.

    1986-01-01

    The positron emitters commonly used in clinical imaging studies for the most part are short-lived, so that when they are distributed in the body the radiation absorbed dose is low even though most of the energy absorbed is from the positrons themselves rather than the annihilation radiation. These considerations do not apply to the administration pathway for a radiopharmaceutical where the activity may be highly concentrated for a brief period rather than distributed in the body. Thus, high local radiation absorbed doses to the vein for an intravenous administration and to the upper airways during administration by inhalation can be expected. For these geometries, beta point source functions (FPS's) have been employed to estimate the radiation absorbed dose in the present study. Physiologic measurements were done to determine other exposure parameters for intravenous administration of O-15 and Rb-82 and for administration of O-15-CO 2 by continuous breathing. Using FPS's to calculate dose rates to the vein wall from O-15 and Rb-82 injected into a vein having an internal radius of 1.5 mm yielded dose rates of 0.51 and 0.46 (rad x g/μCi x h), respectively. The dose gradient in the vein wall and surrounding tissues was also determined using FPS's. Administration of O-15-CO 2 by continuous breathing was also investigated. Using ultra-thin thermoluninescent dosimeters (TLD's) having the effective thickness of normal tracheal mucosa, experiments were performed in which 6 dosimeters were exposed to known concentrations of O-15 positrons in a hemicylindrical tracheal phantom having an internal radius of 0.96 cm and an effective length of 14 cm. The dose rate for these conditions was 3.4 (rads/h)/(μCi/cm 3 ). 15 references, 7 figures, 6 tables

  13. Radiation and shielding around beam absorbers

    International Nuclear Information System (INIS)

    Hurkmans, A.; Maas, R.

    1978-12-01

    During operational conditions it is anticipated that a fair amount of the total available beam power is dumped in either the slit system on one of the beam dumps. Thses beam absorbers therefore become strong radioactive sources. The radiation level due to the absorption of a 100 kW electron beam is estimated and the problem of residual activity is treated. Proposed shielding materials are discussed. (C.F.)

  14. Solar and Net Radiation for Estimating Potential Evaporation from Three Vegetation Canopies

    Science.gov (United States)

    D.M. Amatya; R.W. Skaggs; G.W. Cheschier; G.P. Fernandez

    2000-01-01

    Solar and net radiation data are frequent/y used in estimating potential evaporation (PE) from various vegetative surfaces needed for water balance and hydrologic modeling studies. Weather parameters such as air temperature, relative humidity, wind speed, solar radiation, and net radiation have been continuously monitored using automated sensors to estimate PE for...

  15. Growth, photosynthesis and UV-B absorbing compounds of Portuguese Barbela wheat exposed to ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Correia, C.M.; Torres-Pereira, M.S.; Torres-Pereira, J.M.G.

    1999-01-01

    Wheat plants (Triticum aestivum L.) were exposed to two levels of UV-B radiation (ambient UV-B and high UV-B, simulating a 20% reduction in the ozone layer) under mediterranean field-growth conditions. After 4 months of UV-B treatment, total plant biomass of high UV-B plants was 18% lower compared to control plants. The decrease of biomass appears to be the result of changes in morphological and physiological processes. High UV-B treatment induces decreases in leaf area, net photosynthesis rate, transpiration rate and water use efficiency. Pigment analysis of leaf extracts showed increases in chlorophyll content and no effect on accumulation of UV-B absorbing pigments. The underlying mechanisms for these results are discussed. (author)

  16. Automation of the monitoring in real time of the absorbed dose rate in air due to the environmental gamma radiation in Cuba

    International Nuclear Information System (INIS)

    Dominguez L, O.; Capote F, E.; Carrazana G, J.A.; Manzano de Armas, J.F.; Alonso A, D.; Prendes A, M.; Zerquera, J.T.; Caveda R, C.A.; Kalberg, O.; Fabelo B, O.; Montalvan E, A.; Cartas A, H.; Leyva F, J.C.

    2006-01-01

    The Center of Protection and Hygiene of the Radiations (CPHR) like center rector of the National Net of Environmental Radiological Surveillance (RNVRA), it has strengthened their detection capacity and of answer before a situation of radiological emergency. The measurements of the absorbed dose rate in air due to the environmental gamma radiation in the main stations of the Net are obtained in real time and the CPHR receives the data coming from these posts at one time relatively short. To improve the operability of the RNVRA it was necessary to complete the facilities of existent monitoring using 4 automatic measurement stations with probes of gamma detection, implementing in this way a measurement system on real time. On the other hand the software were developed: GenironProbeFech, to obtain the data of the probes, DataMail for the shipment of the same ones by electronic mail and GammaRed that receives and processes the data in the rector center. (Author)

  17. Role of cytogenetic techniques in biological dosimetry of absorbed radiation

    International Nuclear Information System (INIS)

    Rao, B.S.

    2016-01-01

    In most of the radiation accidents, physical dosimetric information is rarely available. Further, most of the accidental exposures are non-uniform involving either partial body or localized exposure to significant doses. In such situations, physical dosimetry does not provide reliable dose estimate. It has now been realized that biological dosimetric techniques can play an important role in the assessment of absorbed dose. In recent years, a number of biological indicators of radiation have been identified. These include the kinetics of onset and persistence of prodromal syndromes (radiation sickness), cytogenetic changes in peripheral blood lymphocytes, hematological changes, biochemical indicators, ESR spectroscopy of biological samples, induction of gene mutations in red blood cells, cytogenetic and physiological changes in skin and neurophysiological changes. In general, dosimetric information is derived by a combination of several different methods, as they have potential to serve as prognostic indicators. The role of cytogenetic techniques in peripheral blood lymphocytes (PBL) as biological indicators of absorbed radiation is reviewed here

  18. Photoacoustic Determination of Non-radiative Relaxation Time of Absorbing Centers in Maize Seeds

    Science.gov (United States)

    Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

    2017-07-01

    Using non-destructive photothermal techniques, it is possible to characterize non-homogenous materials to obtain its optical and thermal properties through photoacoustic spectroscopy (PAS). In photoacoustic (PA) phenomena, there are transient states of thermal excitation, when samples absorb the incident light; these states manifest an excitation process that generates the PA signal, being in direct relation with the non-radiative relaxation times with the sample absorbent centers. The objective of this study was to determine the non-radiative relaxation times associated with different absorbent centers of corn seeds ( Zea mays L.), by using PAS. A frequency scan was done at different wavelengths (350 nm, 470 nm and 650 nm) in order to obtain the non-radiative relaxation times with different types of maize seeds.

  19. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    Science.gov (United States)

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  20. Analysis of solar radiation transfer: A method to estimate the porosity of a plastic shading net

    International Nuclear Information System (INIS)

    Abdel-Ghany, A.M.; Al-Helal, I.M.

    2011-01-01

    Plastic nets with opaque threads are frequently used for shading agricultural structures under high solar radiation conditions. A parameter that is often used to define a net is the net porosity (Π). Value of Π is usually estimated by one of three methods: image processing, direct beam transmittance, or solar radiation balance (hereafter radiation balance). Image processing is a rather slow process because it requires scanning the net sample at high resolution. The direct beam transmittance and radiation balance methods greatly overestimate Π because some of the solar radiation incident on the thread surfaces is forward scattered and add a considerable amount of radiation to that transmitted from the net pores directly. In this study, the radiation balance method was modified to estimate Π precisely. The amount of solar radiation scattered forward on the thread surfaces was estimated separately. Thus, the un-scattered solar radiation transmitted from the net pores directly, which describes the net porosity, Π could be estimated. This method, in addition to the image processing and the direct beam transmittance methods were used to estimate Π for different types of nets that are commonly used for shading structures in summer. Values of Π estimated by using the proposed method were in good accordance with those measured by the image processing method at a resolution of 4800 dpi. The direct beam transmittance and the radiation balance methods resulted in overestimation errors in the values of Π. This error strongly depends on the color of the net. The estimated errors were +14% for a green net and +37% for a white net when using the radiation balance method, and were +16% and +38%, respectively, when using the direct beam transmittance method. In the image processing method, a resolution of 2400 dpi is sufficient to estimate Π precisely and the higher resolutions showed no significant effect on the value of Π.

  1. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  2. Fast-response cryogenic calorimeter containing a 52-KG radiation absorber

    International Nuclear Information System (INIS)

    Bendt, P.J.; Yarnell, J.L.

    1977-01-01

    An isothermal liquid helium boiloff calorimeter containing a 52-kg copper radiation absorber, and having a time constant 235 U foils irradiated in a nuclear reactor. The short response time was achieved by the large reduction in heat capacity of solids at 4 0 K, and by nearly isothermal operation. Though the initial power level was approx.3 W, the maximum thermal energy storage was approx.1 joule. The Al clad foils were transported in approx.1 s, and cooled to liquid helium temperature in approx.3 s. Boil-off helium gas was warmed to room temperature in a controlled manner, and measured with a hot-film anemometer flowmeter, which was calibrated by comparison with a dry-test volume flowmeter, and by electric heating of the radiation absorber. The correction for gamma leakage from the absorber was less than or equal to 3%, and the correction at short cooling times for sample cooldown, 2.24-m activity of the Al cladding, and system response time, amounted to 3.4% at 10 s. The overall accuracy (1 sigma) of the radiation measurements is less than or equal to 2%, except at the shortest cooling time (10 s), where it rises to 4%

  3. Atlas of albedo and absorbed solar radiation derived from Nimbus 7 earth radiation budget data set, November 1985 to October 1987

    Science.gov (United States)

    Smith, G. Louis; Rutan, David; Bess, T. Dale

    1992-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented for 21 months from Nov. 1985 to Oct. 1987. These data were retrieved from measurements made by the shortwave wide-field-of-view radiometer of the Earth Radiation Budget (ERB) instrument aboard the Nimbus 7 spacecraft. Profiles of zonal mean albedos and absorbed solar radiation were tabulated. These geographical distributions are provided as a resource for researchers studying the radiation budget of the Earth. The El Nino/Southern Oscillation event of 1986-1987 is included in this data set. This atlas of albedo and absorbed solar radiation extends to 12 years the period covered by two similar atlases: NASA RP-1230 (Jul. 1975 - Oct. 1978) and NASA RP-1231 (Nov. 1978 - Oct. 1985). These three compilations complement the atlases of outgoing longwave radiation by Bess and Smith in NASA RP-1185, RP-1186, and RP-1261, which were also based on the Nimbus 6 and 7 ERB data.

  4. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  5. System for determining absorbed dose and its distribution for high-energy electron radiation

    International Nuclear Information System (INIS)

    Hegewald, H.; Wulff, W.

    1977-01-01

    Taking into account the polarization effect, the dose determination for high-energy electron radiation from particle accelerators depends on the knowledge of the energy dependence of the mass stopping power. Results obtained with thermoluminescent dosemeters agree with theoretical values. For absorbed dose measurements the primary energy of electron radiation has been determined by nuclear photoreactions, and the calculation of the absorbed dose from charge measurements by means of the mass stopping power is described. Thus the calibration of ionization chambers for high-energy electron radiation by absolute measurements with the Faraday cage and chemical dosemeters has become possible. (author)

  6. Novel radiator for carbon dioxide absorbents in low-flow anesthesia.

    Science.gov (United States)

    Hirabayashi, Go; Mitsui, Takanori; Kakinuma, Takayasu; Ogihara, Yukihiko; Matsumoto, Shohei; Isshiki, Atsushi; Yasuo, Watanabe

    2003-01-01

    During long-term low-flow sevoflurane anesthesia, dew formation and the generation of compound A are increased in the anesthesia circuit because of elevated soda lime temperature. The object of this study was to develop a novel radiator for carbon dioxide absorbents used for long durations of low-flow sevoflurane anesthesia. Eleven female swine were divided into two groups comprising a "radiator" group (n = 5) that used a novel radiator for carbon dioxide absorbents and a "control" group (n = 6) that used a conventional canister. Anesthesia was maintained with N2O, O2, and sevoflurane, and low-flow anesthesia was performed with fresh gas flow at 0.6 L/min for 12 hr. In the "control" group, the soda lime temperature reached more than 40 degrees C and soda lime dried up with severe dew formation in the inspiratory valve. In the "radiator" group, the temperature of soda lime stayed at 30 degrees C, and the water content of soda lime was retained with no dew formation in the inspiratory valve. In addition, compound A concentration was reduced. In conclusion, radiation of soda lime reduced the amounts of condensation formed and the concentration of compound A in the anesthetic circuit, and allowed long term low-flow anesthesia without equipment malfunction.

  7. Absorbed radiation by various tissues during simulated endodontic radiography

    International Nuclear Information System (INIS)

    Torabinejad, M.; Danforth, R.; Andrews, K.; Chan, C.

    1989-01-01

    The amount of absorbed radiation by various organs was determined by placing lithium fluoride thermoluminescent chip dosimeters at selected anatomical sites in and on a human-like X-ray phantom and exposing them to radiation at 70- and 90-kV X-ray peaks during simulated endodontic radiography. The mean exposure dose was determined for each anatomical site. The results show that endodontic X-ray doses received by patients are low when compared with other radiographic procedures

  8. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  9. Increased light-use efficiency sustains net primary productivity of shaded coffee plants in agroforestry system.

    Science.gov (United States)

    Charbonnier, Fabien; Roupsard, Olivier; le Maire, Guerric; Guillemot, Joannès; Casanoves, Fernando; Lacointe, André; Vaast, Philippe; Allinne, Clémentine; Audebert, Louise; Cambou, Aurélie; Clément-Vidal, Anne; Defrenet, Elsa; Duursma, Remko A; Jarri, Laura; Jourdan, Christophe; Khac, Emmanuelle; Leandro, Patricia; Medlyn, Belinda E; Saint-André, Laurent; Thaler, Philippe; Van Den Meersche, Karel; Barquero Aguilar, Alejandra; Lehner, Peter; Dreyer, Erwin

    2017-08-01

    In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees. © 2017 John Wiley & Sons Ltd.

  10. Electromagnetic radiation absorbers and modulators comprising polyaniline

    Science.gov (United States)

    Epstein, Arthur J.; Ginder, John M.; Roe, Mitchell G.; Hajiseyedjavadi, Hamid

    1992-01-01

    A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

  11. Formulation comprising silicon microparticles, as a pigment that can absorb visible UV radiation and reflect ir radiation

    OpenAIRE

    Rodríguez, Marie-Isabelle; Fenollosa Esteve, Roberto; Meseguer, Francisco

    2011-01-01

    [EN] The invention relates to a formulation characterised in that it comprises silicon microparticles having a size between 0.010 um and 50 um in diameter, and to the use thereof as a pigment that can absorb visible UV radiation and reflect IR radiation.

  12. Generating a heated fluid using an electromagnetic radiation-absorbing complex

    Science.gov (United States)

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2018-01-09

    A vessel including a concentrator configured to concentrate electromagnetic (EM) radiation received from an EM radiation source and a complex configured to absorb EM radiation to generate heat. The vessel is configured to receive a cool fluid from the cool fluid source, concentrate the EM radiation using the concentrator, apply the EM radiation to the complex, and transform, using the heat generated by the complex, the cool fluid to the heated fluid. The complex is at least one of consisting of copper nanoparticles, copper oxide nanoparticles, nanoshells, nanorods, carbon moieties, encapsulated nanoshells, encapsulated nanoparticles, and branched nanostructures. Further, the EM radiation is at least one of EM radiation in an ultraviolet region of an electromagnetic spectrum, in a visible region of the electromagnetic spectrum, and in an infrared region of the electromagnetic spectrum.

  13. Assessment of the methods for determining net radiation at different time-scales of meteorological variables

    Directory of Open Access Journals (Sweden)

    Ni An

    2017-04-01

    Full Text Available When modeling the soil/atmosphere interaction, it is of paramount importance to determine the net radiation flux. There are two common calculation methods for this purpose. Method 1 relies on use of air temperature, while Method 2 relies on use of both air and soil temperatures. Nowadays, there has been no consensus on the application of these two methods. In this study, the half-hourly data of solar radiation recorded at an experimental embankment are used to calculate the net radiation and long-wave radiation at different time-scales (half-hourly, hourly, and daily using the two methods. The results show that, compared with Method 2 which has been widely adopted in agronomical, geotechnical and geo-environmental applications, Method 1 is more feasible for its simplicity and accuracy at shorter time-scale. Moreover, in case of longer time-scale, daily for instance, less variations of net radiation and long-wave radiation are obtained, suggesting that no detailed soil temperature variations can be obtained. In other words, shorter time-scales are preferred in determining net radiation flux.

  14. Observationally constrained estimates of carbonaceous aerosol radiative forcing.

    Science.gov (United States)

    Chung, Chul E; Ramanathan, V; Decremer, Damien

    2012-07-17

    Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm(-2), to be compared with the Intergovernmental Panel on Climate Change's estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm(-2). This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm(-2) (0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm(-2), thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon.

  15. Radiation resistance of pyrocarbon-boned fuel and absorbing elements for HTGR

    International Nuclear Information System (INIS)

    Gurin, V.A.; Konotop, Yu.F.; Odejchuk, N.P.; Shirochenkov, S.D.; Yakovlev, V.K.; Aksenov, N.A.; Kuprienko, V.A.; Lebedev, I.G.; Samsonov, B.V.

    1990-01-01

    In choosing the reactor type, problems of nuclear and radiation safety are outstanding. The analysis of the design and experiments show that HTGR type reactors helium cooled satisfy all the safety requirements. It has been planned in the Soviet Union to construct two HTGR plants, VGR-50 and VG-400. Later it was decided to construct an experimental plant with a low power high temperature reactor (VGM). Spherical uranium-graphite fuel elements with coated fuel particles are supposed to be used in HTGR core. A unique technology for producing spherical pyrocarbon-bound fuel and absorbing elements of monolithic type has been developed. Extended tests were done to to investigate fuel elements behaviour: radiation resistance of coated fuel particles with different types of fuel; influence of the coated fuel particles design on gaseous fission products release; influence of non-sphericity on coated fuel particle performance; dependence of gaseous fission products release from fuel elements on the thickness of fuel-free cans; confining role of pyrocarbon as a factor capable of diminishing the rate of fission products release; radiation resistance of spherical fuel elements during burnup; radiation resistance of spherical absorbing elements to fast neutron fluence and boron burnup

  16. Utilization of radiation protection gear for absorbed dose reduction: an integrative literature review

    International Nuclear Information System (INIS)

    Soares, Flavio Augusto Penna; Flor, Rita de Cassia; Pereira, Aline Garcia

    2011-01-01

    Objective: The present study was aimed at evaluating the relation between the use of radiation protection gear and the decrease in absorbed dose of ionizing radiation, thereby reinforcing the efficacy of its use by both the patients and occupationally exposed personnel. Materials and Methods: The integrative literature review method was utilized to analyze 21 articles, 2 books, 1 thesis, 1 monograph, 1 computer program, 4 pieces of database research (Instituto Brasileiro de Geografia e Estatistica and Departamento de Informatica do Sistema Unico de Saude) and 2 sets of radiological protection guidelines. Results: Theoretically, a reduction of 86% to 99% in the absorbed dose is observed with the use of radiation protection gear. In practice, however, the reduction may achieve 88% in patients submitted to conventional radiology, and 95% in patients submitted to computed tomography. In occupationally exposed individuals, the reduction is around 90% during cardiac catheterization, and 75% during orthopedic surgery. Conclusion: According to findings of several previous pieces of research, the use of radiation protection gear is a low-cost and effective way to reduce absorbed dose both for patients and occupationally exposed individuals. Thus, its use is necessary for the implementation of effective radioprotection programs in radiodiagnosis centers. (author)

  17. Standard Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide describes different mathematical methods that may be used to calculate absorbed dose and criteria for their selection. Absorbed-dose calculations can determine the effectiveness of the radiation process, estimate the absorbed-dose distribution in product, or supplement or complement, or both, the measurement of absorbed dose. 1.2 Radiation processing is an evolving field and annotated examples are provided in Annex A6 to illustrate the applications where mathematical methods have been successfully applied. While not limited by the applications cited in these examples, applications specific to neutron transport, radiation therapy and shielding design are not addressed in this document. 1.3 This guide covers the calculation of radiation transport of electrons and photons with energies up to 25 MeV. 1.4 The mathematical methods described include Monte Carlo, point kernel, discrete ordinate, semi-empirical and empirical methods. 1.5 General purpose software packages are available for the calcul...

  18. Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

    Science.gov (United States)

    Kloeze, C; Klompenhouwer, E G; Brands, P J M; van Sambeek, M R H M; Cuypers, P W M; Teijink, J A W

    2014-03-01

    Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  19. Net Surface Shortwave Radiation from GOES Imagery—Product Evaluation Using Ground-Based Measurements from SURFRAD

    Directory of Open Access Journals (Sweden)

    Anand K. Inamdar

    2015-08-01

    Full Text Available The Earth’s surface net radiation controls the energy and water exchanges between the Earth’s surface and the atmosphere, and can be derived from satellite observations. The ability to monitor the net surface radiation over large areas at high spatial and temporal resolution is essential for many applications, such as weather forecasting, short-term climate prediction or water resources management. The objective of this paper is to derive the net surface radiation in the shortwave domain at high temporal (half-hourly and spatial resolution (~1 km using visible imagery from Geostationary Operational Environmental Satellite (GOES. The retrieval algorithm represents an adaptation to GOES data of a standard algorithm initially developed for the NASA-operated Clouds and Earth’s Radiant Energy System (CERES scanner. The methodology relies on: (1 the estimation of top of atmosphere shortwave radiation from GOES spectral measurements; and (2 the calculation of net surface shortwave (SW radiation accounting for atmospheric effects. Comparison of GOES-retrieved net surface shortwave radiation with ground-measurements at the National Oceanic and Atmospheric Administration’s (NOAA Surface Radiation (SURFRAD stations yields very good agreement with average bias lower than 5 W·m−2 and root mean square difference around 70 W·m−2. The algorithm performance is usually higher over areas characterized by low spatial variability in term of land cover type and surface biophysical properties. The technique does not involve retrieval and assessment of cloud properties and can be easily adapted to other meteorological satellites around the globe.

  20. Radiation absorbed dose from medically administered radiopharmaceuticals

    International Nuclear Information System (INIS)

    Roedler, H.D.; Kaul, A.

    1975-01-01

    The use of radiopharmaceuticals for medical examinations is increasing. Surveys carried out in West Berlin show a 20% average yearly increase in such examinations. This implies an increased genetic and somatic radiation exposure of the population in general. Determination of radiation exposure of the population as well as of individual patients examined requires a knowledge of the radiation dose absorbed by each organ affected by each examination. An extensive survey of the literature revealed that different authors reported widely different dose values for the same defined examination methods and radiopharmaceuticals. The reason for this can be found in the uncertainty of the available biokinetic data for dose calculations and in the application of various mathematical models to describe the kinetics and calculation of organ doses. Therefore, the authors recalculated some of the dose values published for radiopharmaceuticals used in patients by applying biokinetic data obtained from exponential models of usable metabolism data reported in the literature. The calculation of organ dose values was done according to the concept of absorbed fractions in its extended form. For all radiopharmaceuticals used in nuclear medicine the energy dose values for the most important organs (ovaries, testicles, liver, lungs, spleen, kidneys, skeleton, total body or residual body) were recalculated and tabulated for the gonads, skeleton and critical or examined organs respectively. These dose values are compared with those reported in the literature and the reasons for the observed deviations are discussed. On the basis of recalculated dose values for the gonads and bone-marrow as well as on the basis of results of statistical surveys in West Berlin, the genetically significant dose and the somatically (leukemia) significant dose were calculated for 1970 and estimated for 1975. For 1970 the GSD was 0.2 mrad and the LSD was 0.7 mrad. For 1975 the GSD is estimated at < 0.5 mrad and the

  1. Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR

    International Nuclear Information System (INIS)

    Wieser, A.

    2012-01-01

    Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel. (author)

  2. Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR.

    Science.gov (United States)

    Wieser, A

    2012-03-01

    Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel.

  3. Estimating net short-wave radiation with the Bellani pyranometer

    International Nuclear Information System (INIS)

    Bernier, Y.; Plamondon, A.P.

    1983-01-01

    Two methods were developed by which daily net short-wave radiation (K∗) can be evaluated from Bellani pyranometer readings. The first method involves a simple regression equation. The second method uses a physical approach taking into account the effect of the Bellani's geometry on its response to direct and diffuse radiation throughout the day. Both methods, when tested on experimental data, tended to underestimate the measured K∗, the regression approach exhibiting a higher variance of the error [fr

  4. Comparisons of solar radiation interception, albedo and net radiation as influenced by row orientations of crops

    International Nuclear Information System (INIS)

    Baten, Md.A.; Kon, H.

    1997-01-01

    Field experiments were conducted on soybean (Glycin max L.) in summer and potato (Solanum tuberosum L.) in autumn to evaluate the effect of row orientations of crops on some selected micro meteorological factors during 1994 and 1995. The intercepted solar radiation was the largest in the plants growing in bidirection in summer and it exhibited intermediate trend in autumn as compared to E-W or N-S row orientations. In summer, penetrated solar radiation between two plants and near the stem base of a N-S row was larger than that of E-W row. While in autumn, the observed solar radiation between two plants and near the stem base of a E-W row was markedly larger than that of N-S row. The area weighted mean of penetrated solar radiation was larger in E-W soybean rows but lower in potato rows as compared to N-S row orientations. Soil surface temperature between N-S potato rows was larger than that of E-W potato rows and the upper canopy surface temperature of potato was larger in E-W rows as compared to N-S rows. Net radiation observed over E-W potato rows was larger as compared to N-S potato rows but net radiation measured under canopy of E-W potato rows was smaller than that of in N-S rows. Net radiation measured over N-S soybean rows was larger than that of E-W soybean rows and it was smaller between N-S soybean rows when measured under canopy as compared to E-W rows. The albedo observed over potato was larger over E-W rows as compared to N-S rows. Albedos over soybean canopy showed opposite trend with the albedos observed over potato canopy. It was larger over N-S rows as compared to E-W rows. High harvest index was associated with larger interception of radiation. (author)

  5. Radiologist and angiographic procedures. Absorbed radiation dose

    International Nuclear Information System (INIS)

    Tryhus, M.; Mettler, F.A. Jr.; Kelsey, C.

    1987-01-01

    The radiation dose absorbed by the angiographer during angiographic procedures is of vital importance to the radiologist. Nevertheless, most articles on the subject are incomplete, and few measure gonadal dose. In this study, three TLDs were used for each of the following sites: radiologist's eyes, thyroid, gonads with and without shielding apron, and hands. The average dose during carotid angiograms was 2.6, 4.1, 0.4, 4.7, and 7.1 mrads to the eyes, thyroid, gonads with and without .5 mm of lead shielding, and hands, respectively. Average dose during abdominal and peripheral vascular angiographic procedures was 5.2, 7.5, 1.2, 8.5, and 39.9 mrads to the eyes, thyroid, gonads with and without shielding, and hands, respectively. A literature review demonstrates a significant reduction in radiation dose to the angiographer after the advent of automated injectors. Our measured doses for carotid angiography are compatible with contemporary reported values. There was poor correlation with fluoroscopy time and measured dose to the angiographer

  6. Status of radiation dosimetry in Germany using ionization chamber calibrated in terms of absorbed dose to water

    International Nuclear Information System (INIS)

    Hohlfeld, Klaus; Roos, Martin

    1995-01-01

    In 1984 the PTB as PSDL and the DIN Standard Committee on Radiology (NAR) in close co-operation decided that in Germany the measured absorbed dose to water in a water phantom should replace exposure in the dosimetry for radiation therapy. The PTB has established primary standards of water absorbed dose in the whole range of photon and electron radiation, and international comparisons at the BIPM and with other PSDLs proved agreement within 0.5%. Secondary standards are calibrated in a water phantom under reference conditions in a Co-60 gamma radiation beam at the PTB. Thus, the calibration factor in terms of water absorbed dose, N W , is transferred to the manufacturers of dosimeters, the German Calibration Service and the dosimetry laboratories of the verification authorities. The Verification Law subjects each ionization dosimeter used in the treatment of patients with external photon radiation beams under a type-test at PTB and under a verification procedure, where the calibration factor, N W , must be shown to be within given limits. The absorbed dose determination at the users' level follows the foralism prescribed in the Standard DIN 6800-2 (1995) 'Procedures for Absorbed Dose Determination in Radiology by the Ionization Method'. The concept of this DIN Standard uses exclusively one quantity from the primary standard to the user's instrument eliminating uncertainties and sources of mistakes associated with the conversion of a calibration factor. The concept is simple and clear and covers the whole range of photon and electron radiation. As a means of quality assurance in basic dosimetry the PTB runs a calibration service, up to now on a voluntary basis, which allows the user to compare his dosimetry system against PTB standards using mailed Fricke ampoules, with water absorbed dose as measured and used

  7. Geometric radiation exchange factors for axial radiative transfer in an LWR core filled with absorbing-emitting gases

    International Nuclear Information System (INIS)

    Chan, S.H.; Cho, D.H.

    1984-01-01

    A reactor core filled with an emitting-absorbing mixture (like steam, hydrogen gas and fission gases) is considered. Analysis is provided to evaluate axial radiative heat exchange of a rod bundle with a nonuniform axial temperature distribution. The necessary radiation exchange shape factors (geometric mean absorptance, emittance and transmittance) between segments of the complex rod bundle arrangement are presented. They are applicable to arbitrary sizes of segments, well suited for numerical computations

  8. DETERMINATION OF SUPERFICIAL ABSORBED DOSE FROM EXTERNAL EXPOSURE OF WEAKLY PENETRATING RADIATIONS

    Institute of Scientific and Technical Information of China (English)

    陈丽姝

    1994-01-01

    The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported.The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin,cornea,sclera,anterior chamber and lens of eyeball.The ratios among superficial absorbed dose D(0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6mm are also obtained with Cross's methods.They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.

  9. Radiation Synthesis and Application of Absorbent Hydrogels to Enhance the Quality of Basadiesel

    International Nuclear Information System (INIS)

    Nguyen Duy Hang; Pham Thi Le Ha; Tran Thi Thuy; Le Hai; Nguyen Tan Man; Le Huu Tu; Nguyen Trong Hoanh Phong; Tran Thi Tam; Tran Thu Hong; Pham Thi Sam; Nguyen Tuong Li Lan

    2013-01-01

    Studying on the using ability of radiation synthesis hydrogels to enhance the quality of the biodiesel produced from Basa fish oil was implemented. Radiation synthesis of absorbent hydrogels and their application to removal of contaminants from biodiesel produced from fish oil were the major problems. The preparation of the super absorbent hydrogel obtained by radiation induced cross linking of polyacrylamide and polyacrylic was investigated and its application in removal of water, catalyst from the basadiesel emulsion is reported. The hydrogels were characterized in terms of gel content, swelling, character of water and mineral catalyst removal were studied. The effect of temperature, NaOH and KOH content of solution on the swelling degree of hydrogels was also determined. The results showed that the gel fraction of PAAm/PAAc hydrogel with PAAm/AAc (1/4) ratio and dose of 20 kGy was used to synthesized the Gel of A-311. Studies also made on the application of Gel A-311 during the refining process in Basadiesel industry. (author)

  10. Selective fallopian tube catheterisation in female infertility: clinical results and absorbed radiation dose

    International Nuclear Information System (INIS)

    Nakamura, K.; Ishiguchi, T.; Maekoshi, H.; Ando, Y.; Tsuzaka, M.; Tamiya, T.; Suganuma, N.; Ishigaki, T.

    1996-01-01

    Clinical results of fluoroscopic fallopian tube catheterisation and absorbed radiation doses during the procedure were evaluated in 30 infertility patients with unilateral or bilateral tubal obstruction documented on hysterosalpingography. The staged technique consisted of contrast injection through an intrauterine catheter with a vacuum cup device, ostial salpingography with the wedged catheter, and selective salpingography with a coaxial microcatheter. Of 45 fallopian tubes examined, 35 (78 %) were demonstrated by the procedure, and at least one tube was newly demonstrated in 26 patients (87 %). Six of these patients conceived spontaneously in the follow-up period of 1-11 months. Four pregnancies were intrauterine and 2 were ectopic. This technique provided accurate and detailed information in the diagnosis and treatment of tubal obstruction in infertility patients. The absorbed radiation dose to the ovary in the average standardised procedure was estimated to be 0.9 cGy. Further improvement in the X-ray equipment and technique is required to reduce the radiation dose. (orig.). With 3 figs., 3 tabs

  11. Patient absorbed radiation doses estimation related to irradiation anatomy

    International Nuclear Information System (INIS)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes

    2014-01-01

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector

  12. Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Bue, Grant C.; Stephan, Ryan; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2012-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  13. Albedo and estimates of net radiation for green beans under polyethylene cover and field conditions

    International Nuclear Information System (INIS)

    Souza, J.L. de; Escobedo, J.F.; Tornero, M.T.T.

    1999-01-01

    This paper describes the albedo (r) and estimates of net radiation and global solar irradiance for green beans crop (Phaseolus vulgaris L.), cultivated in greenhouse with cover of polyethylene and field conditions, in Botucatu, SP, Brazil (22° 54' S; 48° 27' W; 850 m). The solar global irradiance (R g ) and solar reflected radiation (R r ) were used to estimate the albedo through the ratio between R r and R g . The diurnal curves of albedo were obtained for days with clear sky and partially cloudy conditions, for different phenological stages of the crop. The albedo ranged with the solar elevation, the environment and the phenological stages. The cloudiness range have almost no influence on the albedo diurnal amount. The estimation of radiation were made by linear regression, using the global solar irradiance (R g ) and net short-waves radiation (R c ) as independent variables. All estimates of radiation showed better adjustment for specific phenological periods compared to the entire crop growing cycle. The net radiation in the greenhouse has been estimated by the global solar irradiance measured at field conditions. (author) [pt

  14. Insensitivity of soybean photosynthesis to ultraviolet-B radiation under phosphorus deficiency

    International Nuclear Information System (INIS)

    Murali, N.S.; Teramura, A.H.

    1987-01-01

    Soybean [Glycinemax (L.) Merr. cv Essex] was grown in sand in a greenhouse under 2 levels of biologically effective ultraviolet‐B radiation (effective daily dose: 0 and 11.5 kJ/m UV‐BBE and 2 levels of P (6.5 and 52 μM). Plants were grown in each treatment combination up to the fifth trifoliolate stage. UV‐B radiation had no affect on plant growth and net photosynthesis at 6.5 μM P supply but decreased both these parameters when grown in the higher P concentration. Reductions in net photosynthesis were apparently due to direct effects on the photosynthetic machinery, since chlorophyll concentration and stanatal conductance were unaffected by UV‐B radiation. Both UV‐B radiation and reduced P supply increased the level of UV‐B absorbing compounds in leaf tissues and their effects were additive. The reduced sensitivity of P deficient plants to UV‐B radiation may be the result of this increase in UV absorbing compounds and possibly uv protective mechanisms associated with growth inhibition

  15. Super water absorbent by radiation graft polymerization of acrylic monomers onto cassava starch

    International Nuclear Information System (INIS)

    Doan Binh

    2008-01-01

    Water superabsorbent gel has been applying in personal care, agriculture, medical supplies and water purification. In agricultural application, the gel will help to control soil erosion, limit loss of nutrients and slit for plants, decrease irrigation frequency, improve infiltration, and increase water retention in prolonged arid soil and droughts. The gel absorbs many times its weight in available water. The gel from poly(acrylamide) was developed in the 60's to grow plants in the deserts. The other gel from poly(acrylic acid) was used to absorb rapidly in baby diapers, sanitary napkins. These polymers are commonly produced from natural gas, which have recently been introduced as a soil conditioner with great success. Prior to these polymers, peat moss, agro-waste (sugar-cane waste, coffee-shell, etc.), activated kaolin were the alternative soil additives to hold water (20 times its weight), but poly(acrylamide) absorbs 400 times its weight and polyacrylate is capable of absorbing greater amounts of liquid than poly(acrylamide). In addition, starch and cellulose are biodegradable naturally occurring polymers, which are not capable of holding a great amount of water, but their modification by graft polymerization or crosslinking through radiation or chemical initiation techniques, they become the potential superabsorbent polymers. Radiation initiation of chemical reactions has been widely known for making novel materials because the degree of polymerization, grafting and crosslinking process can easily be controlled. Recently, it was shown that the starch and cellulose derivatives such as carboxymethyl starch, carboxymethyl starch can be synthesized by radiation-induced crosslinking at high concentrations. Their utilization in agriculture seems to be appropriately evaluated. In this article, the graft polymerization and crosslinking of acrylic acid onto cassava starch and field trial of its product (GAM-Sorb S) are reported. (author)

  16. Radiation absorbed dose estimate for Rb-82 using in vivo measurements in man

    International Nuclear Information System (INIS)

    Ryan, J.; Harper, P.; Stark, V.; Peterson, E.; Lathrop, K.

    1984-01-01

    Radiation absorbed doses from intravenous Rb-82 (t 1/2 = 75 sec) were calculated by conjugate counting in 2 healthy adult men aged 27 and 23. Following an i.v. injection of a carefully calibrated amount of Rb-82, an organ of interest was imaged with a gamma camera equipped with a rotating tungsten collimator and data were collected in 10 second frames. Counts in the region of interest were corrected for adjacent background. Imaging was repeated from the opposite side of the body after a second injection. A calibrated reference source of Ge-68 placed on the body over the organ was similarly imaged in the absence of the rubidium activity. The integrated time activity curve in uCi-hours was obtained by comparing the observed kidney net conjugate counts with the reference source conjugate counts which represented a known number of uCi-hours. The organ self doses to the kidneys, liver, lungs, heart, and testes were determined by this technique which eliminated the effects of attenuation. Total absorbed doses to organs from all sources were calculated using the MIRD formulation and the averages of the 2 determinations (mrads/mCi) are as follows: heart (walls) 6.6; kidneys 31.3; liver 4.4; lungs 7.3; testes (1 subject only) 2.4; red marrow 1.7; and whole body 1.9. The highest dose is to the kidneys, but in an older subject (68 yr old man) the measured self dose to the left kidney was 16 mrads/mCi. These data are consistent with the decline in renal blood flow which occurs with increasing age and decreases renal exposure in older patients at increased risk of acute coronary disease who undergo myocardial perfusion imaging with Rb-82

  17. Protection from radiation enteritis by an absorbable polyglycolic acid mesh sling

    International Nuclear Information System (INIS)

    Devereux, D.F.; Thompson, D.; Sandhaus, L.; Sweeney, W.; Haas, A.

    1987-01-01

    Patients with malignant tumors of the pelvis who cannot be cured surgically often are treated with radiation after surgery. A devastating side effect of this treatment is radiation-associated small bowel injury (RASBI). The purpose of this study was to test the hypothesis that removal of the small bowel from the radiation field would protect it against RASBI. Twenty cebus monkeys underwent low anterior resection. In 10 animals an absorbable polyglycolic acid (PGA) mesh was sewn circumferentially around the interior of the abdominal cavity as a supporting apron, which prevented the small bowel's descent into the pelvis. The other 10 monkeys did not receive the mesh. All animals received 2000 rads by linear acceleration in a single dose. Twenty-four-hour stool fat, serum vitamin B12, and other serum values were obtained during the study. Animals were sacrificed after 1, 2, 3, 6, and 12 months, and the small bowel and rectum were examined histologically in a blind manner. Two monkeys who did not undergo surgery, or exposure to radiation served as controls. At all sacrifice periods, the animals with PGA mesh slings demonstrated normal small bowel function and histologic structure. Animals without mesh slings had abnormal stool and blood values at 1 month, and by 2 months all had died of small bowel necrosis. The animals that received the slings had no evidence of infection or obstruction, and by 6 months all evidence of the mesh was gone. Support of the small bowel out of the pelvis by an absorbable PGA mesh sling protects against RASBI and is without apparent complications

  18. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    Energy Technology Data Exchange (ETDEWEB)

    Li, Neng; Chen, Yuhe, E-mail: yuhec@sina.com; Bao, Yongjie; Zhang, Zeqian; Wu, Zaixing; Chen, Zhangmin

    2015-03-30

    Highlights: • We investigate organic UV radiation-absorbing coatings for use on bamboo surfaces. • The size of glass exactly inserted into sample cell of UV-Vis spectrophotometer. • A model was made to predict UV absorption of coatings. • We examine carbonyl groups change of coatings after ageing. • Two formulations which could effectively protect coating were obtained. - Abstract: Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m{sup 2}. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation.

  19. Least-squares collocation meshless approach for radiative heat transfer in absorbing and scattering media

    Science.gov (United States)

    Liu, L. H.; Tan, J. Y.

    2007-02-01

    A least-squares collocation meshless method is employed for solving the radiative heat transfer in absorbing, emitting and scattering media. The least-squares collocation meshless method for radiative transfer is based on the discrete ordinates equation. A moving least-squares approximation is applied to construct the trial functions. Except for the collocation points which are used to construct the trial functions, a number of auxiliary points are also adopted to form the total residuals of the problem. The least-squares technique is used to obtain the solution of the problem by minimizing the summation of residuals of all collocation and auxiliary points. Three numerical examples are studied to illustrate the performance of this new solution method. The numerical results are compared with the other benchmark approximate solutions. By comparison, the results show that the least-squares collocation meshless method is efficient, accurate and stable, and can be used for solving the radiative heat transfer in absorbing, emitting and scattering media.

  20. Least-squares collocation meshless approach for radiative heat transfer in absorbing and scattering media

    International Nuclear Information System (INIS)

    Liu, L.H.; Tan, J.Y.

    2007-01-01

    A least-squares collocation meshless method is employed for solving the radiative heat transfer in absorbing, emitting and scattering media. The least-squares collocation meshless method for radiative transfer is based on the discrete ordinates equation. A moving least-squares approximation is applied to construct the trial functions. Except for the collocation points which are used to construct the trial functions, a number of auxiliary points are also adopted to form the total residuals of the problem. The least-squares technique is used to obtain the solution of the problem by minimizing the summation of residuals of all collocation and auxiliary points. Three numerical examples are studied to illustrate the performance of this new solution method. The numerical results are compared with the other benchmark approximate solutions. By comparison, the results show that the least-squares collocation meshless method is efficient, accurate and stable, and can be used for solving the radiative heat transfer in absorbing, emitting and scattering media

  1. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    International Nuclear Information System (INIS)

    Reynaldo, S. R.; Benavente C, J. A.; Da Silva, T. A.

    2015-10-01

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the 90 Sr/ 90 Y and 85 Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the 90 Sr/ 90 Y and -0.3% for the 85 Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  2. Low Simulated Radiation Limit for Runaway Greenhouse Climates

    Science.gov (United States)

    Goldblatt, Colin; Robinson, Tyler D.; Zahnle, Kevin J.; Crisp, David

    2013-01-01

    Terrestrial planet atmospheres must be in long-term radiation balance, with solar radiation absorbed matched by thermal radiation emitted. For hot moist atmospheres, however, there is an upper limit on the thermal emission which is decoupled from the surface temperature. If net absorbed solar radiation exceeds this limit the planet will heat uncontrollably, the so-called \\runaway greenhouse". Here we show that a runaway greenhouse induced steam atmosphere may be a stable state for a planet with the same amount of incident solar radiation as Earth has today, contrary to previous results. We have calculated the clear-sky radiation limits at line-by-line spectral resolution for the first time. The thermal radiation limit is lower than previously reported (282 W/sq m rather than 310W/sq m) and much more solar radiation would be absorbed (294W/sq m rather than 222W/sq m). Avoiding a runaway greenhouse under the present solar constant requires that the atmosphere is subsaturated with water, and that cloud albedo forcing exceeds cloud greenhouse forcing. Greenhouse warming could in theory trigger a runaway greenhouse but palaeoclimate comparisons suggest that foreseeable increases in greenhouse gases will be insufficient to do this.

  3. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, 2000-present, Net Longwave Radiation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Net Longwave Radiation data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  4. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, 1991-present, Net Shortwave Radiation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Net Shortwave Radiation data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  5. TAO/TRITON, RAMA, and PIRATA Buoys, Daily, 2000-present, Net Longwave Radiation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily Net Longwave Radiation data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  6. Absorbing Aerosols Above Cloud: Detection, Quantitative Retrieval, and Radiative Forcing from Satellite-based Passive Sensors

    Science.gov (United States)

    Jethva, H.; Torres, O.; Remer, L. A.; Bhartia, P. K.

    2012-12-01

    Light absorbing particles such as carbonaceous aerosols generated from biomass burning activities and windblown dust particles can exert a net warming effect on climate; the strength of which depends on the absorption capacity of the particles and brightness of the underlying reflecting background. When advected over low-level bright clouds, these aerosols absorb the cloud reflected radiation from ultra-violet (UV) to shortwave-IR (SWIR) and makes cloud scene darker-a phenomenon commonly known as "cloud darkening". The apparent "darkening" effect can be seen by eyes in satellite images as well as quantitatively in the spectral reflectance measurements made by space borne sensors over regions where light absorbing carbonaceous and dust aerosols overlay low-level cloud decks. Theoretical radiative transfer simulations support the observational evidence, and further reveal that the strength of the cloud darkening and its spectral signature (or color ratio) between measurements at two wavelengths are a bi-function of aerosol and cloud optical thickness (AOT and COT); both are measures of the total amount of light extinction caused by aerosols and cloud, respectively. Here, we developed a retrieval technique, named as the "color ratio method" that uses the satellite measurements at two channels, one at shorter wavelength in the visible and one at longer wavelength in the shortwave-IR for the simultaneous retrieval of AOT and COT. The present technique requires assumptions on the aerosol single-scattering albedo and aerosol-cloud separation which are supplemented by the Aerosol Robotic Network (AERONET) and space borne CALIOP lidar measurements. The retrieval technique has been tested making use of the near-UV and visible reflectance observations made by the Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) for distinct above-cloud smoke and dust aerosol events observed seasonally over the southeast and tropical Atlantic Ocean

  7. Standard Guide for Absorbed-Dose Mapping in Radiation Processing Facilities

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This document provides guidance in determining absorbed-dose distributions in products, materials or substances irradiated in gamma, X-ray (bremsstrahlung) and electron beam facilities. Note 1—For irradiation of food and the radiation sterilization of health care products, other specific ISO and ISO/ASTM standards containing dose mapping requirements exist. For food irradiation, see ISO/ASTM 51204, Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing and ISO/ASTM 51431, Practice for Dosimetry in Electron and Bremsstrahlung Irradiation Facilities for Food Processing. For the radiation sterilization of health care products, see ISO 11137: 1995, Sterilization of Health Care Products Requirements for Validation and Routine Control Radiation Sterilization. In those areas covered by ISO 11137, that standard takes precedence. ISO/ASTM Practice 51608, ISO/ASTM Practice 51649, and ISO/ASTM Practice 51702 also contain dose mapping requirements. 1.2 Methods of analyzing the dose map data ar...

  8. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    Energy Technology Data Exchange (ETDEWEB)

    Rink, Alexandra; Lewis, David F.; Varma, Sangya; Vitkin, I. Alex; Jaffray, David A. [Princess Margaret Hospital/Ontario Cancer Institute, Department of Medical Biophysics and Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Advanced Materials Group, International Specialty Products, Inc., Wayne, New Jersey 07470 (United States); Princess Margaret Hospital/Ontario Cancer Institute, Department of Medical Biophysics and Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2008-10-15

    The effects of temperature on real time changes in optical density ({Delta}OD) of GAFCHROMIC EBT film were investigated. The spectral peak of maximum change in absorbance ({lambda}{sub max}) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 degree sign C. The {Delta}OD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in {lambda}{sub max}. A compensation scheme using {lambda}{sub max} and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry.

  9. Comparison of the standards for absorbed dose to water of the ARPANSA and the BIPM for 60Co γ radiation

    International Nuclear Information System (INIS)

    Allisy-Roberts, P.J.; Burns, D.T.; Boas, J.F.; Huntley, R.B.; Wise, K.N.

    2000-10-01

    A comparison of the standards for absorbed dose to water of the Australian Radiation Protection and Nuclear Safety Agency and of the Bureau International des Poids et Mesures (BIPM) has been carried out in 60 Co gamma radiation. The Australian standard is based on a graphite calorimeter and the subsequent conversion from absorbed dose to graphite to absorbed dose to water using the photon fluence scaling theorem. The BIPM standard is ionometric using a graphite-walled cavity ionization chamber. The comparison result is 1.0024 (standard uncertainty 0.0029). (authors)

  10. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    Energy Technology Data Exchange (ETDEWEB)

    Reynaldo, S. R. [Development Centre of Nuclear Technology, Posgraduate Course in Science and Technology of Radiations, Minerals and Materials / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Benavente C, J. A.; Da Silva, T. A., E-mail: sirr@cdtn.br [Development Centre of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the {sup 90}Sr/{sup 90}Y and {sup 85}Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the {sup 90}Sr/{sup 90}Y and -0.3% for the {sup 85}Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  11. Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2013-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  12. The design of a calorimetric standard of ionising radiation absorbed dose

    International Nuclear Information System (INIS)

    Huntley, R.B.

    1981-05-01

    The design of a calorimetric working standard of ionising radiation absorbed dose is discussed. A brief history of the appropriate quantities and units of measurement is given. Detailed design considerations follow a summary of the relevant literature. The methods to be used to relate results to national standards of measurement are indicated, including the need for various correction factors. A status report is given on the construction and testing program

  13. Covering that selectively absorbs visible and infrared radiation, and method for the production thereof

    OpenAIRE

    Céspedes, Eva; Prieto, C.; Escobar Galindo, R.; Sánchez-García, J. A.

    2011-01-01

    [EN] The present invention relates to a covering that selectively absorbs visible and infrared radiation, which comprises: (a) a first anti-diffusion barrier layer (2); (b) an IR-reflecting metallic layer (3) made from at least one metallic element selected from a group comprising Au, Ag, Al, Cu, Ti and Pt; (c) at least a second anti-diffusion barrier layer (4) formed by oxidation of the layer (3); (d) a structure that absorbs in the UV-VIS range, which comprises at least a first film (5) and...

  14. Investigation of absorbed radiation dose in refraction-enhanced breast tomosynthesis by a Laue case analyser

    International Nuclear Information System (INIS)

    Sato, H.; Ando, M.; Shimao, D.

    2011-01-01

    An early diagnosis system for breast cancer using refraction-enhanced breast tomosynthesis is under development. Tomograms of breast specimens based on refraction-contrast were demonstrated using the simplest shift-and-add tomosynthesis algorithm. Raw projection image data of breast specimens for tomosynthesis were acquired for a total of 51 views over an angle of 50 deg., in increments of 1 deg., by rotating the object. The incident X ray was monochromatic synchrotron radiation with 20 keV. The purpose of this study was to estimate the absorbed dose of a new X-ray imaging method. As breast cancer almost always arises in glandular breast tissue, the average absorbed dose in such glandular tissue should be measured to estimate the radiation risk associated with mammography. The absorbed dose of the mammary gland due to monochromatic X rays was calculated by the Monte Carlo method, and the optimal X ray energy range for refraction-enhanced breast tomosynthesis was investigated through actual measurements. Compared with the conventional method, it was found to be below one-sixth per inspection. (authors)

  15. Radiation sterilization of absorbent cotton and of absorbent gauze

    International Nuclear Information System (INIS)

    Hosobuchi, Kazunari; Oka, Mitsuru; Kaneko, Akira; Ishiwata, Hiroshi.

    1986-01-01

    The bioburden of absorbent cotton and of absorbent gauze and their physical and chemical characteristics after irradiation are investigated. The survey conducted on contaminants of 1890 cotton samples from 53 lots and 805 gauze samples from 56 lots showed maximum numbers of microbes per g of the cotton and gauze were 859 (an average of 21.4) and 777 (an average of 42.2), respectively. Isolation and microbiological and biochemical tests of representative microbes indicated that all of them, except one, were bacilli. The sterilization dose at 10 -6 of sterlity assurance level was found to be 2.0 Mrad when irradiated the spores loaded on paper strips and examined populations having graded D values from 0.10 to 0.28 Mrad. The sterilization dose would be about 1.5 Mrad if subjected the average numbers of contaminants observed in this study to irradiation. No significant differences were found between the irradiated samples and control up to 2 Mrad in tensile strength, change of color, absorbency, sedimentation rate, soluble substances, and pH of solutions used for immersion and other tests conventionally used. These results indicate that these products can be sterilized by irradiation. (author)

  16. Experimental studies on absorbed dose in radiation sterilization of pharmaceutical preparation

    International Nuclear Information System (INIS)

    Ohnishi, Tokuhiro; Okamoto, Shinichi; Kimura, Syojiro; Taimatsu, Meiko.

    1991-01-01

    For radiation sterilization, it is necessary to decide the irradiation conditions considering a balance between sterilization efficiency and chemical changes of samples by irradiation. These effects may be estimated by the product of two factors (D 10 and G value) and absorbed dose. In this work, it has been found experimentally by using Fricke dosimeter that the absorbed doses of the samples in vessels different in size, material, volume, etc. are not equal under the same gamma-ray irradiation condition. The correction factor from exposure to absorbed dose was estimated to be 6-7% for organic vessels (a polyethylene bag and a polystyrene vial) and a 20-ml glass vial, 9% for a 10-ml glass vial, and 10% for the 5-ml glass vial. These values of the correction factor were confirmed by using the changes of enzymic activity of saccharated powder pepsin preparation. In the cases of using organic vessels and the 10-ml glass vial, G-values for the change of the enzymic activity were calculated to show similar values in the range from 0.79 to 0.82. However, in the case of a small glass vial (5-ml), the value was 0.93. (author)

  17. TAO/TRITON, RAMA, and PIRATA Buoys, 5-Day, 2000-present, Net Longwave Radiation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has 5-day Net Longwave Radiation data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  18. Warm Absorber Diagnostics of AGN Dynamics

    Science.gov (United States)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  19. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1986-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 references, 3 figures, 2 tables

  20. Comparative technical-economical analysis of solar systems with liquid absorbent

    International Nuclear Information System (INIS)

    Kaloyanov, N.; Popova, I.

    2005-01-01

    An analyses of solar water heating systems with two types liquid absorbent is presented. A system with classic collector design is used for comparison. The dependence between the value of the collectors active area and the absorbent type, collectors slope and design parameters is discussed. Two economic indexes (payback period and index of actual net value, based on the electricity price) are used for comparison of the different variants of the system. The presented results shown that: 1) the payback period can be reduced twice if the collectors with liquid absorbent are used; 2) the index of actual net value of the systems using the collectors with fluid absorbent is about four times higher than this one with classic collectors; 3) the systems using distilled water like a liquid absorbent can not fulfil the requirements for the positive economic indicators

  1. Tomographic apparatus and method for reconstructing planar slices from non-absorbed radiation

    International Nuclear Information System (INIS)

    1976-01-01

    In a tomographic apparatus and method for reconstructing two-dimensional planar slices from linear projections of non-absorbed radiation useful in the fields of medical radiology, microscopy, and non-destructive testing, a beam of radiation in the shape of a fan is passed through an object lying in the same quasi-plane as the object slice and non-absorbtion thereof is recorded on oppositely-situated detectors aligned with the source of radiation. There is relative rotation between the source-detector configuration and the object within the quasi-plane. Periodic values of the detected radiation are taken, convolved with certain functions, and back-projected to produce a two-dimensional output picture on a visual display illustrating a facsimile of the object slice. A series of two-dimensional pictures obtained simultaneously or serially can be combined to produce a three dimensional portrayal of the entire object

  2. A Ten-Year Global Record of Absorbing Aerosols Above Clouds from OMI's Near-UV Observations

    Science.gov (United States)

    Jethva, Hiren; Torres, Omar; Ahn, Changwoo

    2016-01-01

    Aerosol-cloud interaction continues to be one of the leading uncertain components of climate models, primarily due to the lack of an adequate knowledge of the complex microphysical and radiative processes associated with the aerosol-cloud system. The situations when aerosols and clouds are found in the same atmospheric column, for instance, when light-absorbing aerosols such as biomass burning generated carbonaceous particles or wind-blown dust overlay low-level cloud decks, are commonly found over several regional of the world. Contrary to the cloud-free scenario over dark surface, for which aerosols are known to produce a net cooling effect (negative radiative forcing) on climate, the overlapping situation of absorbing aerosols over cloud can potentially exert a significant level of atmospheric absorption and produces a positive radiative forcing at top-of-atmosphere. The magnitude of direct radiative effects of aerosols above cloud depends directly on the aerosol loading, microphysical-optical properties of the aerosol layer and the underlying cloud deck, and geometric cloud fraction. We help in addressing this problem by introducing a novel product of optical depth of absorbing aerosols above clouds retrieved from near-UV observations made by the Ozone Monitoring Instrument (OMI) on board NASA's Aura platform. The presence of absorbing aerosols above cloud reduces the upwelling radiation reflected by cloud and produces a strong 'color ratio' effect in the near-UV region, which can be unambiguously detected in the OMI measurements. Physically based on this effect, the OMACA algorithm retrieves the optical depths of aerosols and clouds simultaneously under a prescribed state of atmosphere. The algorithm architecture and results from a ten-year global record including global climatology of frequency of occurrence and above-cloud aerosol optical depth, and a discussion on related future field campaigns are presented.

  3. Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

    Science.gov (United States)

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-05-19

    A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

  4. The Australian Commonwealth standard of measurement for absorbed radiation dose. Part 1

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1989-08-01

    As an agent for the Commonwealth Scientific and Industrial Research Organisation, the Australian Nuclear Science and Technology Organisation is responsible for maintenance of the Australian Commonwealth standard of absorbed dose. This standard of measurement has application in radiation therapy dosimetry, which is required for the treatment of cancer patients. This report is the first in a series of reports documenting the absorbed dose standard for photon beams in the range from 1 to 25 MeV. The Urquhart graphite micro-calorimeters, which is used for the determination of absorbed dose under high energy photon beams, has been now placed under computer control. Accordingly, a complete upgrade of the calorimeter systems was performed to allow operation in the hospital. In this report, control and monitoring techniques have been described, with an assessment of the performance achieved being given for 6 and 18 MeV bremsstrahlung beams. Random errors have been reduced to near negligible proportions, while systematic errors have been minimized by achieving true quasi-adiabatic operation. 16 refs., 9 tabs., 11 figs

  5. Inconsistencies in net radiation estimates from use of several models of instruments in a desert environment

    International Nuclear Information System (INIS)

    Kustas, W.P.; Prueger, J.H.; Hipps, L.E.; Hatfield, J.L.; Meek, D.

    1998-01-01

    Studies of surface energy and water balance generally require an accurate estimate of net radiation and its spatial distribution. A project quantifying both short term and seasonal water use of shrub and grass vegetation in the Jornada Experimental Range in New Mexico prompted a study to compare net radiation observations using two types of net radiometers currently being used in research. A set of 12 REBS net radiometers were compared with each other and one Swissteco, over wet and dry surfaces in an arid landscape under clear skies. The set of REBS exhibited significant differences in output over both surfaces. However, they could be cross calibrated to yield values within 10 W m −2 , on average. There was also a significant bias between the REBS and Swissteco over a dry surface, but not over a wet one. The two makes of instrument could be made to agree under the dry conditions by using regression or autoregression techniques. However, the resulting equations would induce bias for the wet surface condition. Thus, it is not possible to cross calibrate these two makes of radiometer over the range of environmental conditions observed. This result indicates that determination of spatial distribution of net radiation over a variable surface should be made with identical instruments which have been cross calibrated. The need still exists for development of a radiometer and calibration procedures which will produce accurate and consistent measurements over a range of surface conditions. (author)

  6. Effect of gamma radiation on chlorophylls contents, net photosynthesis and respiration of chlorella pyrenoidosa

    International Nuclear Information System (INIS)

    Fernandez Gonzalez, J.; Martin Moreno, C.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first 'b' chlorophyll affected to a greater extent than 'a' chlorophyll. Net photosynthesis and respiration decline throughout the time of the observations after irradiation, this depressing effect being much more remarkable for the first one. Net photosynthesis inhibition levels of about 30% have got only five hours post irradiation at a dose of 5000 Gy. (author)

  7. Assessment of absorbed dose rate from terrestrial gamma radiation in Red Sea State

    International Nuclear Information System (INIS)

    Abdalrahman, H. E. K.

    2012-09-01

    This study is primarily conducted to contribute in the overall strategic objective of producing Sudan radiation map which will include natural radiation levels and the resultant absorbed dose rate in air. The part covered by this study is the Red Sea State. Soil samples were collected from locations lie between latitudes 17.03 ° and the 20.18 ° N and longitudes 36.06 ° E during September 2007. Activity concentrations of the primordial radionuclides, 226 Ra, 232 Th, and 40 K in the samples were measured using gamma-ray spectrometry equipped with Nal (Tl) detector. Absorbed dose rates in air a height of 1 from the ground level and the corresponding annual effective doses were calculated from the measured activities using Dose Rate Conversion Factors (DRCFs). On the average, the activity concentrations were 19.22±13.13 Bq kg -1 ( 232 Th), 17.91±15.44 Bq kg -1 ( 226 Ra) and (507.13±161.67) Bq kg -1 for 40 K. The obtained results were found to be within the global values reported in the UNSCEAR publication for normal background areas with the exception of the samples taken from Arbaat area. The absorbed dose rate in air as calculated using UNSCEAR conversion factor averaged 40.93 n Gy h -1 which corresponds to annual effective dose of 50.23 μSvy -1 . The major contribution to the total absorbed dose rate comes from 40 K, which amounts to 53.36%. Using Geographical Information System (GIS), predication maps for activity concentrations levels of the measured radionuclides in the Red Sea state was prepared to show their respective spatial distributions. Similarly, GIS predictive map was produced for annual effective dose.(Author)

  8. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1985-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, 1/2d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 refs., 3 figs., 2 tabs

  9. Regional scale net radiation estimation by means of Landsat and TERRA/AQUA imagery and GIS modeling

    Science.gov (United States)

    Cristóbal, J.; Ninyerola, M.; Pons, X.; Llorens, P.; Poyatos, R.

    2009-04-01

    Net radiation (Rn) is one of the most important variables for the estimation of surface energy budget and is used for various applications including agricultural meteorology, climate monitoring and weather prediction. Moreover, net radiation is an essential input variable for potential as well as actual evapotranspiration modeling. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute net radiation at regional scales in a feasible way. In this study we present a regional scale estimation of the daily Rn on clear days, (Catalonia, NE of the Iberian Peninsula), using a set of 22 Landsat images (17 Landsat-5 TM and 5 Landsat-7 ETM+) and 171 TERRA/AQUA images MODIS from 2000 to 2007 period. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected three different types of products which contain the remote sensing data we have used to model daily Rn: daily LST product, daily calibrated reflectances product and daily atmospheric water vapour product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital Elevation Model, obtaining an RMS less than 30 m. Radiometric correction of Landsat non-thermal bands has been done following the methodology proposed by Pons and Solé (1994), which allows to reduce the number of undesired artifacts that are due to the effects of the atmosphere or to the differential illumination which is, in turn, due to the time of the day, the location in the Earth and the relief (zones being more illuminated than others, shadows, etc). Atmospheric correction of Landsat thermal band has been carried out by means of a single-channel algorithm improvement developed by Cristóbal et al. (2009) and the land surface emissivity computed by means of the methodology proposed by Sobrino and Raissouni (2000). Rn has been estimated through the

  10. Improving solar radiation absorbance of high refractory sintered ceramics by fs Ti:sapphire laser surface treatment

    International Nuclear Information System (INIS)

    Cappelli, E.; Orlando, S.; Sciti, D.; Bellucci, A.; Lettino, A.; Trucchi, D.M.

    2014-01-01

    Samples of high refractory pressure-less sintered carbide ceramics (HfC based), polished by mechanical grinding to a surface roughness R a ∼ 40 nm, have been surface treated, in vacuum, by fs Ti:sapphire laser, operating at 800 nm wavelength, 1000 Hz repetition rate and 100 fs pulse duration, at fluence varying in the range (∼6–25 J/cm 2 ), to optimize their solar radiation absorbance, in such a way that they could operate as absorber material in an innovative conversion module of solar radiation into electrical energy. To this aim, an area of approximately 9.6 cm 2 was treated by the fs laser beam. The beam strikes perpendicular to the sample, placed on a stage set in motion in the x, y, z-directions, thus generating a scanning pattern of parallel lines. The experimental conditions of laser treatment (energy fluence, speed of transition, overlapping and lateral step distance) were varied in order to optimize the radiation absorption properties of the patterned surface. In laser treated samples the absorption value is increased by about 15%, compared to the original untreated surface, up to a value of final absorbance of about 95%, all over the range of solar radiation spectrum (from UV to IR). The morphological and chemical effects of the treatment have been evaluated by SEM–EDS analysis. At very high fluence, we obtained the characteristic ablation craters and local material decomposition, while at lower fluence (in any case above the threshold) typical periodic nano-structures have been obtained, exploitable for their modified optical properties.

  11. Estimation of the absorbed dose in radiation-processed food. Pt.2

    International Nuclear Information System (INIS)

    Desrosiers, M.F.

    1991-01-01

    The use of electron paramagnetic resonance spectroscopy to accurately evaluate the absorbed dose to radiation-processed bones (and thus meats) is examined. Additive re-irradiation of the bone produces a reproducible response function which can be used to evaluate the initial dose by back-extrapolation. It was found that an exponential fit (vs linear or polynomial) to the data provides improved accuracy of the estimated dose. These data as well as the protocol for the additive dose method are presented. (author)

  12. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and a significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  13. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of Ho-166 Microspheres in Liver Radioembolization

    NARCIS (Netherlands)

    Seevinck, Peter R.; van de Maat, Gerrit H.; de Wit, Tim C.; Vente, Maarten A. D.; Nijsen, Johannes F. W.; Bakker, Chris J. G.

    2012-01-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional Ho-166 activity distribution to estimate radiation-absorbed dose distributions in Ho-166-loaded poly (L-lactic acid) microsphere (Ho-166-PLLA-MS) liver radioembolization.

  14. Reliability test: X-ray ring exit chambers crotch radiation absorbers. Final report

    International Nuclear Information System (INIS)

    Lynch, D.R.; Morgan, J.

    1999-01-01

    This report details the efforts by engineers at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory (BNL) to evaluate the reliability of water-cooled radiation absorbers used in the NSLS X-ray ring. These absorbers are part of the 16 dipole vacuum chambers which comprise the arc sections of the ring. They are located at the intersections (crotch) of the beamline exit ports with the electron beam chamber, and are commonly referred to as crotches. The purpose of these efforts was to demonstrate the reliability of the crotches under operating conditions that the crotches will be subjected to over the entire expected life of the ring. The efforts described include engineering calculations, finite element analysis, conceptual design for a reliability test, test implementation and descriptions, results and conclusions related to these analyses and tests

  15. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2011-01-01

    , nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  16. Radiation dosages absorbed by the skin during videofluorographic examination of velopharyngeal function

    International Nuclear Information System (INIS)

    Ohara, Hirotoshi; Ogata, Hisao; Nakajima, Tatsuo; Sone, Kiyoaki

    2008-01-01

    Radiographic assessment has become essential in examining the function of the soft palate and pharyngeal walls in patients with velopharyngeal insufficiency. However, in our search of the literature, there was no report on the exposure dose during videofluorographic examination of velopharyngeal function in Japan. Radiation dosages from videofluorography were measured by attaching a glass dosimeter to the submental skin in 17 patients undergoing examination of velopharyngeal function. Sixteen patients underwent a complete videofluorographic examination. For these 16 patients, the mean time of examination was 96.4 sec; the mean radiation dosage absorbed by the skin was 14.4 mGy, equivalent to approximately 7 standard skull x-rays and lower than that during other fluoroscopic procedures. This dose was also lower than the threshold dose at which the skin damage occurs. In light of increasing concern among the general public over radiation exposure, we consider that these data should provide useful information to patients being asked to give informed consent for this examination. (author)

  17. A simulation model for the actual, long wave and net solar radiation computing

    International Nuclear Information System (INIS)

    Kolev, B.; Stoilov, A.; Lyubomirov, L.

    2004-01-01

    The main purpose of this study is to present a calculating procedure for the components of the radiation balance - actual, long-wave and net radiation calculation, using the sunshine duration and the standard meteorological information, through a previously prepared program product.To calculate the actual solar radiation using the total cloudiness only, an empirical regression model has been developed. The results of the coefficient of correlation R(0.75-0.88), respectively for the spring and summer periods (March-May; June-August) show the adequacy of the chosen model. The verification of the model on the independent experimental material prove that the approach that authors suggested, can be successfully applied to the calculation of the actual radiation of the current place

  18. Combined Natural Convection and Radiation Heat Transfer of Various Absorbing-Emitting-Scattering Media in a Square Cavity

    Directory of Open Access Journals (Sweden)

    Xianglong Liu

    2014-01-01

    Full Text Available A numerical model is developed to simulate combined natural convection and radiation heat transfer of various anisotropic absorbing-emitting-scattering media in a 2D square cavity based on the discrete ordinate (DO method and Boussinesq assumption. The effects of Rayleigh number, optical thickness, scattering ratio, scattering phase function, and aspect ratio of square cavity on the behaviors of heat transfer are studied. The results show that the heat transfer of absorbing-emitting-scattering media is the combined results of radiation and natural convection, which depends on the physical properties and the aspect ratio of the cavity. When the natural convection becomes significant, the convection heat transfer is enhanced, and the distributions of NuR and Nuc along the walls are obviously distorted. As the optical thickness increases, NuR along the hot wall decreases. As the scattering ratio decreases, the NuR along the walls decreases. At the higher aspect ratio, the more intensive thermal radiation and natural convection are formed, which increase the radiation and convection heat fluxes. This paper provides the theoretical research for the optimal thermal design and practical operation of the high temperature industrial equipments.

  19. The evaluation of lens absorbed dose according to the optimold for whole brain radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong Mo; Park, Byoung Suk; Ahn, Jong Ho; Song, Ki Won [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-06-15

    In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made up to 5 mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. When there was the Optimold mask in the eyeball part, it was measured at 10.2cGy ± 1.5 in the simulation therapy, and at 24.8cGy ± 2.7 in the treatment, and when the Optimold mask was removed in the eye part, it was measured at 12.9cGy ± 2.2 in the simulation therapy, and at 17.6cGy ± 1.5 in the treatment. In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3cGy in the simulation therapy and was reduced approximately 7cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause

  20. The evaluation of lens absorbed dose according to the optimold for whole brain radiation therapy

    International Nuclear Information System (INIS)

    Yang, Yong Mo; Park, Byoung Suk; Ahn, Jong Ho; Song, Ki Won

    2014-01-01

    In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made up to 5 mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. When there was the Optimold mask in the eyeball part, it was measured at 10.2cGy ± 1.5 in the simulation therapy, and at 24.8cGy ± 2.7 in the treatment, and when the Optimold mask was removed in the eye part, it was measured at 12.9cGy ± 2.2 in the simulation therapy, and at 17.6cGy ± 1.5 in the treatment. In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3cGy in the simulation therapy and was reduced approximately 7cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause

  1. Net radiative forcing and air quality responses to regional CO emission reductions

    Directory of Open Access Journals (Sweden)

    M. M. Fry

    2013-05-01

    Full Text Available Carbon monoxide (CO emissions influence global and regional air quality and global climate change by affecting atmospheric oxidants and secondary species. We simulate the influence of halving anthropogenic CO emissions globally and individually from 10 regions on surface and tropospheric ozone, methane, and aerosol concentrations using a global chemical transport model (MOZART-4 for the year 2005. Net radiative forcing (RF is then estimated using the GFDL (Geophysical Fluid Dynamics Laboratory standalone radiative transfer model. We estimate that halving global CO emissions decreases global annual average concentrations of surface ozone by 0.45 ppbv, tropospheric methane by 73 ppbv, and global annual net RF by 36.1 mW m−2, nearly equal to the sum of changes from the 10 regional reductions. Global annual net RF per unit change in emissions and the 100 yr global warming potential (GWP100 are estimated as −0.124 mW m−2 (Tg CO−1 and 1.34, respectively, for the global CO reduction, and ranging from −0.115 to −0.131 mW m−2 (Tg CO−1 and 1.26 to 1.44 across 10 regions, with the greatest sensitivities for regions in the tropics. The net RF distributions show widespread cooling corresponding to the O3 and CH4 decreases, and localized positive and negative net RFs due to changes in aerosols. The strongest annual net RF impacts occur within the tropics (28° S–28° N followed by the northern midlatitudes (28° N–60° N, independent of reduction region, while the greatest changes in surface CO and ozone concentrations occur within the reduction region. Some regional reductions strongly influence the air quality in other regions, such as East Asia, which has an impact on US surface ozone that is 93% of that from North America. Changes in the transport of CO and downwind ozone production clearly exceed the direct export of ozone from each reduction region. The small variation in CO GWPs among world regions suggests that future international

  2. Tumoral fibrosis effect on the radiation absorbed dose of 177Lu–Tyr3-octreotate and 177Lu–Tyr3-octreotate conjugated to gold nanoparticles

    International Nuclear Information System (INIS)

    Azorín-Vega, E.P.; Zambrano-Ramírez, O.D.; Rojas-Calderón, E.L.; Ocampo-García, B.E.; Ferro-Flores, G.

    2015-01-01

    The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals 177 Lu–Tyr 3 -octreotate (monomeric) and 177 Lu–Tyr 3 -octreotate–gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112 Gy-multimeric vs. 43 Gy-monomeric). - Highlights: • Fibrosis increases the radiation absorbed dose to the tumor. • Fibrosis increases the radiopharmaceutical residence time in the tumor. • The multimeric nature of the radiopharmaceuticals enhances the radiopharmaceutical retention

  3. Estimation of organ-absorbed radiation doses during 64-detector CT coronary angiography using different acquisition techniques and heart rates: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Kosuke; Koshida, Kichiro; Kawashima, Hiroko (Dept. of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa Univ., Kanazawa (Japan)), email: matsuk@mhs.mp.kanazawa-u.ac.jp; Noto, Kimiya; Takata, Tadanori; Yamamoto, Tomoyuki (Dept. of Radiological Technology, Kanazawa Univ. Hospital, Kanazawa (Japan)); Shimono, Tetsunori (Dept. of Radiology, Hoshigaoka Koseinenkin Hospital, Hirakata (Japan)); Matsui, Osamu (Dept. of Radiology, Faculty of Medicine, Kanazawa Univ., Kanazawa (Japan))

    2011-07-15

    Background: Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important. Purpose: To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates. Material and Methods: Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio. Results: For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively. Conclusion: ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients' heart rate appropriately during ECG-gated helical acquisition with

  4. 26 CFR 1.1502-21 - Net operating losses.

    Science.gov (United States)

    2010-04-01

    ..., gain, deduction, and loss, including the member's losses and deductions actually absorbed by the group... income, gain, deduction, and loss. For this purpose— (A) Consolidated taxable income is computed without... the group has no Year 2 capital gain, it cannot absorb any capital losses in Year 2. T's Year 1 net...

  5. On the definition of absorbed dose

    International Nuclear Information System (INIS)

    Grusell, Erik

    2015-01-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before. - Highlights: • A stringent definition of absorbed dose is given. • This requires the definition of an irradiation and a suitable probability space. • A stringent definition is important for an understanding of the concept absorbed dose

  6. Automation of the monitoring in real time of the absorbed dose rate in air due to the environmental gamma radiation in Cuba; Automatizacion del monitoreo en tiempo real de la tasa de dosis absorbida en aire debido a la radiacion gamma ambiental en Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez L, O; Capote F, E; Carrazana G, J A; Manzano de Armas, J F; Alonso A, D; Prendes A, M; Zerquera, J T; Caveda R, C A [CPHR, Calle 20, No. 4113 e/41 y 47, Playa, La Habana, 11300, A.P. 6195 C.P. 10600 (Cuba); Kalberg, O [Swedish Radiation Protection Institute (SSI) (Sweden); Fabelo B, O; Montalvan E, A [CIAC, Camaguey (Cuba); Cartas A, H [CEAC, Cienfuegos (Cuba); Leyva F, J C [CISAT (Cuba)

    2006-07-01

    The Center of Protection and Hygiene of the Radiations (CPHR) like center rector of the National Net of Environmental Radiological Surveillance (RNVRA), it has strengthened their detection capacity and of answer before a situation of radiological emergency. The measurements of the absorbed dose rate in air due to the environmental gamma radiation in the main stations of the Net are obtained in real time and the CPHR receives the data coming from these posts at one time relatively short. To improve the operability of the RNVRA it was necessary to complete the facilities of existent monitoring using 4 automatic measurement stations with probes of gamma detection, implementing in this way a measurement system on real time. On the other hand the software were developed: GenironProbeFech, to obtain the data of the probes, DataMail for the shipment of the same ones by electronic mail and GammaRed that receives and processes the data in the rector center. (Author)

  7. Radiation absorbed doses at radiographic examination of third molars

    International Nuclear Information System (INIS)

    Rehnmark-Larsson, S.; Stenstroem, B.; Julin, P.; Richter, S.; Huddinge University Hospital

    1981-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. The greatest thyroid dose, 35 μGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. the corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50 %. The Ekta-Speed film requirted approximately 40 % lower exposure than the Ultra-Speed film. A horizontal radiation shield reduced the thyroid doses by between 12 and 46 % and the gonadal doses by between 50 and 95 %. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses between 15 and 42 % and the gonadal doses by two orders of magnitude. (Authors)

  8. Preparation of highly absorbing polymeric hydrogels by radiation processing: mechanical and physical properties

    International Nuclear Information System (INIS)

    Dragusin, M.

    1994-01-01

    Some highly absorbing polymeric hydrogels such as acrylic polymers were produced by radiation processing with gamma sources Co-60 of 10,000 Ci, 3 kGy/h and an electron beam accelerator of 3 - 6 MeV, 0.3 - 3 kGy/s. For practical purposes, such as different applications in agriculture, etc, we studied the physical properties of residual monomers by refractometric and polarographic methods and the mechanical properties (gel strength) with devices made in our laboratory. (Author)

  9. Specific features of accounting the time and spatial distribution of absorbed dose during the assessment of radiation casualties in current circumstances

    International Nuclear Information System (INIS)

    Chernyavskyij, I.Yu.

    2015-01-01

    This article presents an attempt to assess the necessity of accounting the spatial and time distribution of absorbed dose of mixed radiations of main radiation factors for the correct estimation of the troops' capabilities in the system of military dosimetry

  10. Evaluation of a combined modelling-remote sensing method for estimating net radiation in a wetland: a case study in the Nebraska Sand Hills, USA

    International Nuclear Information System (INIS)

    Goodin, D.G.

    1995-01-01

    Close-range measurement combined with modelling of incoming radiation is used to evaluate the prospect of remotely-measuring net radiation of a wetland environment located in the Sand Hills of Nebraska. Results indicate that net radiation can be measured with an accuracy comparable to that of conventional instruments. Sources of error are identified and discussed. Possible application of the methodology to satellite remote sensing is considered. (author)

  11. Flower garden trees' ability to absorb solar radiation heat for local heat reduction

    Science.gov (United States)

    Maulana, Muhammad Ilham; Syuhada, Ahmad; Hamdani

    2017-06-01

    Banda Aceh as an urban area tends to have a high air temperature than its rural surroundings. A simple way to cool Banda Aceh city is by planting urban vegetation such as home gardens or parks. In addition to aesthetics, urban vegetation plays an important role as a reducer of air pollution, oxygen producer, and reducer of the heat of the environment. To create an ideal combination of plants, knowledge about the ability of plants to absorb solar radiation heat is necessary. In this study, some types of flowers commonly grown by communities around the house, such as Michelia Champaka, Saraca Asoka, Oliander, Adenium, Codiaeum Variegatum, Jas Minum Sambac, Pisonia Alba, Variegata, Apium Graveolens, Elephantopus Scaber, Randia, Cordylin.Sp, Hibiscus Rosasinensis, Agave, Lili, Amarilis, and Sesamum Indicum, were examined. The expected benefit of this research is to provide information for people, especially in Banda Aceh, on the ability of each plant relationship in absorbing heat for thermal comfort in residential environments. The flower plant which absorbs most of the sun's heat energy is Hibiscus Rosasinensis (kembang sepatu) 6.2 Joule, Elephantopus Scaber.L (tapak leman) 4.l Joule. On the other hand, the lowest heat absorption is Oliander (sakura) 0.9 Joule.

  12. Optimum combinations of visible and near-infrared reflectances for estimating the fraction of photosynthetically available radiation absorbed by plants

    Science.gov (United States)

    Podaire, Alain; Deschamps, Pierre-Yves; Frouin, R.; Asrar, Ghassem

    1991-01-01

    A useful parameter to estimate terrestrial primary productivity, that can be sensed from space, is the daily averaged fraction of Photosynthetically Available Radiation (PAR) absorbed by plants. To evaluate this parameter, investigators have relied on the fact that the relative amount of radiation reflected by a vegetated surface in the visible and near infrared depends on the fraction of the surface covered by the vegetation and therefore, correlates with absorbed PAR. They have used vegetation indices, namely normalized difference and simple ratio, to derive absorbed PAR. The problem with normalized difference and simple ratio is first, they are non linear functions of radiance or reflectance and therefore, cannot be readily applied to heterogeneous targets, second, they are used in generally nonlinear relationships, which make time integrals of the indices not proportional to primary productivity, and third, the relationships depend strongly on the type of canopy and background. To remove these limitations, linear combinations of visible and near infrared reflectances at optimum (one or two) viewing zenith angles are proposed.

  13. RadNet Air Data From Sacramento, CA

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Sacramento, CA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  14. RadNet Air Data From Honolulu, HI

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Honolulu, HI from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  15. RadNet Air Data From Houston, TX

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Houston, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  16. RadNet Air Data From Austin, TX

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Austin, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  17. RadNet Air Data From Orlando, FL

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Orlando, FL from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  18. Solar radiation absorbing material

    Science.gov (United States)

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  19. UV-absorbing compounds in subarctic herbarium bryophytes

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen, S. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)]. E-mail: satu.huttunen@oulu.fi; Lappalainen, N.M. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland); Turunen, J. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)

    2005-01-01

    The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A{sub 280-320nm}) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time.

  20. UV-absorbing compounds in subarctic herbarium bryophytes

    International Nuclear Information System (INIS)

    Huttunen, S.; Lappalainen, N.M.; Turunen, J.

    2005-01-01

    The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A 280-320nm ) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time

  1. Estimation of snow albedo reduction by light absorbing impurities using Monte Carlo radiative transfer model

    Science.gov (United States)

    Sengupta, D.; Gao, L.; Wilcox, E. M.; Beres, N. D.; Moosmüller, H.; Khlystov, A.

    2017-12-01

    Radiative forcing and climate change greatly depends on earth's surface albedo and its temporal and spatial variation. The surface albedo varies greatly depending on the surface characteristics ranging from 5-10% for calm ocean waters to 80% for some snow-covered areas. Clean and fresh snow surfaces have the highest albedo and are most sensitive to contamination with light absorbing impurities that can greatly reduce surface albedo and change overall radiative forcing estimates. Accurate estimation of snow albedo as well as understanding of feedbacks on climate from changes in snow-covered areas is important for radiative forcing, snow energy balance, predicting seasonal snowmelt, and run off rates. Such information is essential to inform timely decision making of stakeholders and policy makers. Light absorbing particles deposited onto the snow surface can greatly alter snow albedo and have been identified as a major contributor to regional climate forcing if seasonal snow cover is involved. However, uncertainty associated with quantification of albedo reduction by these light absorbing particles is high. Here, we use Mie theory (under the assumption of spherical snow grains) to reconstruct the single scattering parameters of snow (i.e., single scattering albedo ῶ and asymmetry parameter g) from observation-based size distribution information and retrieved refractive index values. The single scattering parameters of impurities are extracted with the same approach from datasets obtained during laboratory combustion of biomass samples. Instead of using plane-parallel approximation methods to account for multiple scattering, we have used the simple "Monte Carlo ray/photon tracing approach" to calculate the snow albedo. This simple approach considers multiple scattering to be the "collection" of single scattering events. Using this approach, we vary the effective snow grain size and impurity concentrations to explore the evolution of snow albedo over a wide

  2. Modeling UV Radiation Feedback from Massive Stars. II. Dispersal of Star-forming Giant Molecular Clouds by Photoionization and Radiation Pressure

    Science.gov (United States)

    Kim, Jeong-Gyu; Kim, Woong-Tae; Ostriker, Eve C.

    2018-05-01

    UV radiation feedback from young massive stars plays a key role in the evolution of giant molecular clouds (GMCs) by photoevaporating and ejecting the surrounding gas. We conduct a suite of radiation hydrodynamic simulations of star cluster formation in marginally bound, turbulent GMCs, focusing on the effects of photoionization and radiation pressure on regulating the net star formation efficiency (SFE) and cloud lifetime. We find that the net SFE depends primarily on the initial gas surface density, Σ0, such that the SFE increases from 4% to 51% as Σ0 increases from 13 to 1300 {M}ȯ {pc}}-2. Cloud destruction occurs within 2–10 Myr after the onset of radiation feedback, or within 0.6–4.1 freefall times (increasing with Σ0). Photoevaporation dominates the mass loss in massive, low surface density clouds, but because most photons are absorbed in an ionization-bounded Strömgren volume, the photoevaporated gas fraction is proportional to the square root of the SFE. The measured momentum injection due to thermal and radiation pressure forces is proportional to {{{Σ }}}0-0.74, and the ejection of neutrals substantially contributes to the disruption of low mass and/or high surface density clouds. We present semi-analytic models for cloud dispersal mediated by photoevaporation and by dynamical mass ejection, and show that the predicted net SFE and mass loss efficiencies are consistent with the results of our numerical simulations.

  3. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

  4. The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape.

    Science.gov (United States)

    Helbig, Manuel; Chasmer, Laura E; Kljun, NatasCha; Quinton, William L; Treat, Claire C; Sonnentag, Oliver

    2017-06-01

    At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. In boreal lowlands, thawing forested permafrost peat plateaus ('forest') lead to expansion of permafrost-free wetlands ('wetland'). Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH 4 ) emissions. Here, we quantify the thaw-induced increase in CH 4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO 2 ) exchange. Using nested wetland and landscape eddy covariance net CH 4 flux measurements in combination with flux footprint modeling, we find that landscape CH 4 emissions increase with increasing wetland-to-forest ratio. Landscape CH 4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May-October) wetland CH 4 emission of ~13 g CH 4  m -2 is the dominating contribution to the landscape CH 4 emission of ~7 g CH 4  m -2 . In contrast, forest contributions to landscape CH 4 emissions appear to be negligible. The rapid wetland expansion of 0.26 ± 0.05% yr -1 in this region causes an estimated growing season increase of 0.034 ± 0.007 g CH 4  m -2  yr -1 in landscape CH 4 emissions. A long-term net CO 2 uptake of >200 g CO 2  m -2  yr -1 is required to offset the positive radiative forcing of increasing CH 4 emissions until the end of the 21st century as indicated by an atmospheric CH 4 and CO 2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and eddy covariance landscape net CO 2 flux measurements suggest a long-term net CO 2 uptake between 49 and 157 g CO 2  m -2  yr -1 . Thus, thaw-induced CH 4 emission increases likely exert a positive net radiative greenhouse gas

  5. Self-diffraction of continuous laser radiation in a disperse medium with absorbing particles

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya.; Maksimyak, P. P.

    2013-01-01

    We study the self-action of light in a water suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams...... formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles' displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating...

  6. Evaluation of three semi-empirical approaches to estimate the net radiation over a drip-irrigated olive orchard

    Directory of Open Access Journals (Sweden)

    Rafael López-Olivari

    2015-09-01

    Full Text Available The use of actual evapotranspiration (ETα models requires an appropriate parameterization of the available energy, where the net radiation (Rn is the most important component. Thus, a study was carried out to calibrate and evaluate three semi-empirical approaches to estimate net radiation (Rn over a drip-irrigated olive (Olea europaea L. 'Arbequina' orchard during 2009/2010 and 2010/2011 seasons. The orchard was planted in 2005 at high density in the Pencahue Valley, Maule Region, Chile. The evaluated models were calculated using the balance between long and short wave radiation. To achieve this objective it was assumed that Ts = Tα for Model 1, Ts = Tv for Model 2 and Ts = Tr for Model 3 (Ts is surface temperature; Tα is air temperature; and Tv is temperature inside of the tree canopy; Tr is radiometric temperature. For the three models, the Brutsaert's empirical coefficient (Φ was calibrated using incoming long wave radiation equation with the database of 2009/2010 season. Thus, the calibration indicated that Φ was equal to 1.75. Using the database from 2010/2011 season, the validation indicated that the three models were able to predict the Rn at a 30-min interval with errors lower than 6%, root mean square error (RMSE between 26 and 39 W m-2 and mean absolute error (MAE between 20 and 31 W m-2. On daily time intervals, validation indicated that models presented errors, RMSE and MAE between 2% and 3%, 1.22-1.54 and 1.04-1.35 MJ m-2 d-1, respectively. The three R„-Models would be evaluated and used in others Mediterranean conditions according to the availability of data to estimate net radiation over a drip-irrigated olive orchard planted at high density.

  7. Conceptual basis for calculations of absorbed-dose distributions

    International Nuclear Information System (INIS)

    Sinclair, W.K.; Rossi, H.H.; Alsmiller, R.G.; Berger, M.J.; Kellerer, A.M.; Roesch, W.C.; Spencer, L.V.; Zaider, M.A.

    1991-01-01

    The effects of radiation on matter are initiated by processes in which atoms and molecules of the medium are ionized or excited. Over a wide range of conditions, it is an excellent approximation to assume that the average number of ionizations and excitations is proportional to the amount of energy imparted to the medium by ionizing radiation in the volume of interest. The absorbed dose, that is, the average amount of energy imparted to the medium per unit mass, is therefore of central importance for the production of radiation effects, and the calculation of absorbed-dose distributions in irradiated media is the focus of interest of the present report. It should be pointed out, however, that even though absorbed dose is useful as an index relating absorbed energy to radiation effects, it is almost never sufficient; it may have to be supplemented by other information, such as the distributions of the amounts of energy imparted to small sites, the correlation of the amounts of energy imparted to adjacent sites, and so on. Such quantities are termed stochastic quantities. Unless otherwise stated, all quantities considered in this report are non-stochastic. 266 refs., 11 figs., 2 tabs

  8. A robust method for determining the absorbed dose to water in a phantom for low-energy photon radiation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T, E-mail: thorsten.schneider@ptb.de [Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig (Germany)

    2011-06-07

    The application of more and more low-energy photon radiation in brachytherapy-either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes-has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible to measure the absorbed dose with calorimetric methods in this low energy range, ionometric methods are the preferred choice. However, the determination of the absorbed dose to water in water by ionometric methods is difficult in this energy range. With decreasing energy, the relative uncertainty of the photon cross sections increases and as the mass energy transfer coefficients show a steep gradient, the spectra of the radiation field must be known precisely. In this work two ionometric methods to determine the absorbed dose to water are evaluated with respect to their sensitivity to the uncertainties of the spectra and of the atomic database. The first is the measurement of the air kerma free in air and the application of an MC-based conversion factor to the absorbed dose to water. The second is the determination of the absorbed dose to water by means of an extrapolation chamber as an integral part of a phantom. In the complementing MC-calculations, two assortments of spectra each of which is based on a separate unfolding procedure were used as well as two kinds of databases: the standard PEGS and the recently implemented NIST database of EGSnrc. Experimental results were obtained by using a parallel-plate graphite extrapolation chamber and a free-air chamber. In the case when the water kerma in a phantom is determined from the measurements of air kerma free in air, differences in the order of 10% were found, according to which the database or the kind of spectrum is used. In contrast to this, for the second method, the differences found were about 0.5%.

  9. Calculations in the Wheeler-Feynman absorber theory of radiation

    International Nuclear Information System (INIS)

    Balaji, K.S.

    1986-01-01

    One dimensional computer aided calculations were done to find the self consistent solutions for various absorber configurations in the context of the Wheeler-Feynman absorber theory, wherein every accelerating charge is assumed to produce a time symmetric combination of advanced and retarded fields. These calculations picked out the so called outerface solution for incomplete absorbers and showed that advanced as well as retarded signals interact with matter in the same manner as in the full retarded theory. Based on these calculations, the Partridge experiment and the Schmidt-Newman experiment were ruled out as tests of the absorber theory. An experiment designed to produce and detect advanced effects is proposed, based on more one-dimensional calculations

  10. Effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme in bean (Phaseolus vulgaris L.) grown under different nitrogen conditions.

    Science.gov (United States)

    Pinto, M E; Casati, P; Hsu, T P; Ku, M S; Edwards, G E

    1999-02-01

    The effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme have been examined in different cultivars of Phaseolous vulgaris L. grown under 1 and 12 mM nitrogen. Low nitrogen nutrition reduces chlorophyll and soluble protein contents in the leaves and thus the photosynthesis rate and dry-matter accumulation. Chlorophyll, soluble protein and Rubisco contents and photosynthesis rate are not significantly altered by ambient levels of UV-B radiation (17 microW m-2, 290-320 nm, 4 h/day for one week). Comparative studies show that under high nitrogen, UV-B radiation slightly enhances leaf expansion and dry-matter accumulation in cultivar Pinto, but inhibits these parameters in Vilmorin. These results suggest that the UV-B effect on growth is mediated through leaf expansion, which is particularly sensitive to UV-B, and that Pinto is more tolerant than Vilmorin. The effect of UV-B radiation on UV-B-absorbing compounds and on NADP-malic enzyme (NADP-ME) activity is also examined. Both UV-B radiation and low-nitrogen nutrition enhance the content of UV-B-absorbing compounds, and among the three cultivars used, Pinto exhibits the highest increases and Arroz the lowest. The same trend is observed for the specific activity and content of NADP-ME. On a leaf-area basis, the amount of UV-B-absorbing compounds is highly correlated with the enzyme activity (r2 = 0.83), suggesting that NADP-ME plays a key role in biosynthesis of these compounds. Furthermore, the higher sensitivity of Vilmorin than Pinto to UV-B radiation appears to be related to the activity of NADP-ME and the capacity of the plants to accumulate UV-B-absorbing compounds.

  11. Radiative effects of absorbing aerosols over northeastern India: Observations and model simulations

    Science.gov (United States)

    Gogoi, Mukunda M.; Babu, S. Suresh; Moorthy, K. Krishna; Bhuyan, Pradip Kumar; Pathak, Binita; Subba, Tamanna; Chutia, Lakhima; Kundu, Shyam Sundar; Bharali, Chandrakala; Borgohain, Arup; Guha, Anirban; De, Barin Kumar; Singh, Brajamani; Chin, Mian

    2017-01-01

    Multiyear measurements of spectral properties of aerosol absorption are examined over four geographically distinct locations of northeastern India. Results indicated significant spatiotemporal variation in aerosol absorption coefficients (σabs) with highest values in winter and lowest in monsoon. The western parts of the region, close to the outflow of Indo-Gangetic Plains, showed higher values of σabs and black carbon (BC) concentration—mostly associated with fossil fuel combustion. But, the eastern parts showed higher contributions from biomass-burning aerosols, as much as 20-25% to the total aerosol absorption, conspicuously during premonsoon season. This is attributed to a large number of burning activities over the Southeast Asian region, as depicted from Moderate Resolution Imaging Spectroradiometer fire count maps, whose spatial extent and magnitude peaks during March/April. The nearly consistent high values of aerosol index (AI) and layer height from Ozone Monitoring Instrument indicate the presence of absorbing aerosols in the upper atmosphere. The observed seasonality has been captured fairly well by Goddard Chemistry Aerosol Radiation and Transport (GOCART) as well as Weather Research and Forecasting-Chemistry (WRF-Chem) model simulations. The ratio of column-integrated optical depths due to particulate organic matter and BC from GOCART showed good coincidence with satellite-based observations, indicating the increased vertical dispersion of absorbing aerosols, probably by the additional local convection due to higher fire radiative power caused by the intense biomass-burning activities. In the WRF-Chem though underperformed by different magnitude in winter, the values are closer or overestimated near the burnt areas. Atmospheric forcing due to BC was highest ( 30 Wm-2) over the western part associated with the fossil fuel combustion.

  12. Accuracy assessment of a net radiation and temperature index snowmelt model using ground observations of snow water equivalent in an alpine basin

    Science.gov (United States)

    Molotch, N. P.; Painter, T. H.; Bales, R. C.; Dozier, J.

    2003-04-01

    In this study, an accumulated net radiation / accumulated degree-day index snowmelt model was coupled with remotely sensed snow covered area (SCA) data to simulate snow cover depletion and reconstruct maximum snow water equivalent (SWE) in the 19.1-km2 Tokopah Basin of the Sierra Nevada, California. Simple net radiation snowmelt models are attractive for operational snowmelt runoff forecasts as they are computationally inexpensive and have low input requirements relative to physically based energy balance models. The objective of this research was to assess the accuracy of a simple net radiation snowmelt model in a topographically heterogeneous alpine environment. Previous applications of net radiation / temperature index snowmelt models have not been evaluated in alpine terrain with intensive field observations of SWE. Solar radiation data from two meteorological stations were distributed using the topographic radiation model TOPORAD. Relative humidity and temperature data were distributed based on the lapse rate calculated between three meteorological stations within the basin. Fractional SCA data from the Landsat Enhanced Thematic Mapper (5 acquisitions) and the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) (2 acquisitions) were used to derive daily SCA using a linear regression between acquisition dates. Grain size data from AVIRIS (4 acquisitions) were used to infer snow surface albedo and interpolated linearly with time to derive daily albedo values. Modeled daily snowmelt rates for each 30-m pixel were scaled by the SCA and integrated over the snowmelt season to obtain estimates of maximum SWE accumulation. Snow surveys consisting of an average of 335 depth measurements and 53 density measurements during April, May and June, 1997 were interpolated using a regression tree / co-krig model, with independent variables of average incoming solar radiation, elevation, slope and maximum upwind slope. The basin was clustered into 7 elevation / average-solar-radiation

  13. Ground-plane-less bidirectional terahertz absorber based on omega resonators

    NARCIS (Netherlands)

    Balmakou, Alexei; Podalov, Maxim; Khakhomov, Sergei; Stavenga, Doekele; Semchenko, Igor

    2015-01-01

    We present a new ultrathin metamaterial that acts as a frequency-selective absorber of terahertz radiation. The absorber is a square array of pairs of omega-shaped micro-resonators made of high-ohmic-loss metal. The metamaterial provides significant suppression of transmitted and reflected radiation

  14. Effect of ultraviolet radiation absorbing film on pollination work of foreign bumblebee [Bombus terrestris

    International Nuclear Information System (INIS)

    Nishiguchi, I.

    1999-01-01

    The transmitted light through the ultraviolet radiation absorbing (UVA) film has a preventing effect of disease and pest occurrence. To develop the agriculture harmonized with the ecosystem, we attempted to research a further possible utilization of the UVA film. Pollination work of foreign bumblebee (Bombus terrestris) in the greenhouses roofed with UVA film and with common film for agriculture was examined in growing fruit-vegetables. The bumblebees used were not acclimatized to environmental conditions of the greenhouses. They visited flowers and gathered pollen from flowered crops grown in both houses, irrespective of the kind of film covering over the greenhouse roof, and the pollen quantity gathered was far greater in crops which produced in large quantity of pollen. Thus, the bumblebees were capable to work under the condition lacking in ultraviolet radiation. This pollinating behavior is different from that of honeybees. Then we concluded that bumblebees functioned well as an efficient pollinator under the condition without ultraviolet radiation

  15. Absorbed dose to mice in prolonged irradiation by low-dose rate ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, Akihiro [National Inst. of Radiological Sciences, Chiba (Japan); Saitou, Mikio; Kudo, Iwao [and others

    2000-07-01

    In this paper, the dose absorbed by mice was evaluated as a preliminary study of the late effects of prolonged continuous irradiation of mice with low-dose rate ionizing radiation. Eight-week-old male and female SPF C3H/HeN mice in three irradiation rooms were exposed to irradiation at 8000, 400, and 20 mGy, respectively, using a {sup 137}Cs {gamma}-source. Nine racks were arranged in a circle approximately 2.5 m from the source in each room, and 10 cages were arranged on the 4 shelves of each rack. Dose distributions, such as in air at the source level, in the three rooms were estimated by using ionization chambers, and the absorbed dose distributions in the room and relative dose distributions in the cages in relation to the distance of the cage center were examined. The mean abdomen doses of the mice measured by TLD were compared with the absorbed doses in the cages. The absorbed dose distributions showed not only inverse-inverse-square-law behavior with distance from the source, but geometric symmetry in every room. The inherent scattering and absorption in each room are responsible for such behavior and asymmetry. Comparison of relative dose distributions revealed cage positions that are not suitable for experiments with high precision doses, but all positions can be used for prolonged continuous irradiation experiments if the position of the cages is rotated regularly. The mean abdomen doses of the mice were similar in each cage. The mean abdomen doses of the mice and the absorbed doses in a cage were almost the same in all cages. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about {+-}12% for 8000 mGy group, 17% for 400 mGy group, and 35% for 20 mGy group. (K.H.)

  16. Report on the results of the FY 1998 hydrogen utilization international clean energy system technology (WE-NET). Subtask 5. Survey on the R and D of technologies for hydrogen transport and storage by hydrogen absorbing alloys (V. Development of the distributed transport/storage use hydrogen absorbing alloys); 1998 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET). 5. Suiso yuso chozo gijutsu no kaihatsu (V. bunsan yuso chozoyo suiso kyuzo gokin no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The paper described the FY 1998 results of the development of hydrogen distributed transport/storage use absorbing alloys in the WE-NET project. Study was made of improvement of hydrogen desorption characteristics by substituting Ca for part of Mg of Mg-Ni alloys and substituting Cr for part of Ni. It is necessary to shift the state of atomic bond by H atom and metal atom in alloys from the ionic bond to the metallic bond, and to change from the amorphous state to the BCC type crystal structure. It was found out that it was possible to do it by improving the composition and heat treatment. The addition of Cu to LaMg{sub 2} alloys shifts the bond with hydrogen to the bond with metal. Easy hydrogen desorption and large absorbing capacity can be expected. It was found out that LaMg{sub 2}Cu{sub 2} synthesized by the reaction sintering method has reversible hydrogen absorbing desorption characteristics. The absorbing amount is 2.4 wt%, the desorption amount 1.2 wt%, and the desorption temperature 190 degrees C. Those are still far from WE-NET targeted values, but a clue to the search was obtained. It was found out that by applying doping technology by Ti, etc. to NaAlH{sub 4}, characteristics can be expected of the desorption amount, 4.5 wt%, of the hydrogen desorption starting temperature from 100 degrees C to 200 degrees C. (NEDO)

  17. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  18. On the Momentum Transported by the Radiation Field of a Long Transient Dipole and Time Energy Uncertainty Principle

    Directory of Open Access Journals (Sweden)

    Vernon Cooray

    2016-11-01

    Full Text Available The paper describes the net momentum transported by the transient electromagnetic radiation field of a long transient dipole in free space. In the dipole a current is initiated at one end and propagates towards the other end where it is absorbed. The results show that the net momentum transported by the radiation is directed along the axis of the dipole where the currents are propagating. In general, the net momentum P transported by the electromagnetic radiation of the dipole is less than the quantity U / c , where U is the total energy radiated by the dipole and c is the speed of light in free space. In the case of a Hertzian dipole, the net momentum transported by the radiation field is zero because of the spatial symmetry of the radiation field. As the effective wavelength of the current decreases with respect to the length of the dipole (or the duration of the current decreases with respect to the travel time of the current along the dipole, the net momentum transported by the radiation field becomes closer and closer to U / c , and for effective wavelengths which are much shorter than the length of the dipole, P ≈ U / c . The results show that when the condition P ≈ U / c is satisfied, the radiated fields satisfy the condition Δ t Δ U ≥ h / 4 π where Δ t is the duration of the radiation, Δ U is the uncertainty in the dissipated energy and h is the Plank constant.

  19. Spectral estimates of net radiation and soil heat flux

    International Nuclear Information System (INIS)

    Daughtry, C.S.T.; Kustas, W.P.; Moran, M.S.; Pinter, P.J. Jr.; Jackson, R.D.; Brown, P.W.; Nichols, W.D.; Gay, L.W.

    1990-01-01

    Conventional methods of measuring surface energy balance are point measurements and represent only a small area. Remote sensing offers a potential means of measuring outgoing fluxes over large areas at the spatial resolution of the sensor. The objective of this study was to estimate net radiation (Rn) and soil heat flux (G) using remotely sensed multispectral data acquired from an aircraft over large agricultural fields. Ground-based instruments measured Rn and G at nine locations along the flight lines. Incoming fluxes were also measured by ground-based instruments. Outgoing fluxes were estimated using remotely sensed data. Remote Rn, estimated as the algebraic sum of incoming and outgoing fluxes, slightly underestimated Rn measured by the ground-based net radiometers. The mean absolute errors for remote Rn minus measured Rn were less than 7%. Remote G, estimated as a function of a spectral vegetation index and remote Rn, slightly overestimated measured G; however, the mean absolute error for remote G was 13%. Some of the differences between measured and remote values of Rn and G are associated with differences in instrument designs and measurement techniques. The root mean square error for available energy (Rn - G) was 12%. Thus, methods using both ground-based and remotely sensed data can provide reliable estimates of the available energy which can be partitioned into sensible and latent heat under non advective conditions

  20. Performance of an absorbing concentrating solar collectors

    International Nuclear Information System (INIS)

    Imadojemu, H.

    1990-01-01

    This paper reports on a comparison of the efficiency of an absorbing fluid parabolic trough concentrating solar collector and a traditional concentrating collector that was made. In the absorbing fluid collector, black liquid flows through a glass tube absorber while the same black liquid flows through a selective black coated copper tube absorber while the same black fluid flows through a selective black coated copper tube absorber in the traditional collector. After a careful study of the properties of available black liquids, a mixture of water and black ink was chosen as the black absorbing medium or transfer fluid. In the black liquid glass collector there is a slightly improved efficiency based on beam radiation as a result of the direct absorption process and an increase in the effective transmittance absorptance. At worst the efficiency of this collector equals that of the traditional concentrating collector when the efficiency is based on total radiation. The collector's reflecting surfaces were made of aluminum sheet, parabolic line focus and with cylindrical receivers. The ease of manufacture and reduced cost per unit energy collected, in addition to the clean and pollution free mode of energy conversion, makes it very attractive

  1. Use of MODIS Sensor Images Combined with Reanalysis Products to Retrieve Net Radiation in Amazonia

    Science.gov (United States)

    de Oliveira, Gabriel; Brunsell, Nathaniel A.; Moraes, Elisabete C.; Bertani, Gabriel; dos Santos, Thiago V.; Shimabukuro, Yosio E.; Aragão, Luiz E. O. C.

    2016-01-01

    In the Amazon region, the estimation of radiation fluxes through remote sensing techniques is hindered by the lack of ground measurements required as input in the models, as well as the difficulty to obtain cloud-free images. Here, we assess an approach to estimate net radiation (Rn) and its components under all-sky conditions for the Amazon region through the Surface Energy Balance Algorithm for Land (SEBAL) model utilizing only remote sensing and reanalysis data. The study period comprised six years, between January 2001–December 2006, and images from MODIS sensor aboard the Terra satellite and GLDAS reanalysis products were utilized. The estimates were evaluated with flux tower measurements within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project. Comparison between estimates obtained by the proposed method and observations from LBA towers showed errors between 12.5% and 16.4% and 11.3% and 15.9% for instantaneous and daily Rn, respectively. Our approach was adequate to minimize the problem related to strong cloudiness over the region and allowed to map consistently the spatial distribution of net radiation components in Amazonia. We conclude that the integration of reanalysis products and satellite data, eliminating the need for surface measurements as input model, was a useful proposition for the spatialization of the radiation fluxes in the Amazon region, which may serve as input information needed by algorithms that aim to determine evapotranspiration, the most important component of the Amazon hydrological balance. PMID:27347957

  2. Use of MODIS Sensor Images Combined with Reanalysis Products to Retrieve Net Radiation in Amazonia.

    Science.gov (United States)

    de Oliveira, Gabriel; Brunsell, Nathaniel A; Moraes, Elisabete C; Bertani, Gabriel; Dos Santos, Thiago V; Shimabukuro, Yosio E; Aragão, Luiz E O C

    2016-06-24

    In the Amazon region, the estimation of radiation fluxes through remote sensing techniques is hindered by the lack of ground measurements required as input in the models, as well as the difficulty to obtain cloud-free images. Here, we assess an approach to estimate net radiation (Rn) and its components under all-sky conditions for the Amazon region through the Surface Energy Balance Algorithm for Land (SEBAL) model utilizing only remote sensing and reanalysis data. The study period comprised six years, between January 2001-December 2006, and images from MODIS sensor aboard the Terra satellite and GLDAS reanalysis products were utilized. The estimates were evaluated with flux tower measurements within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project. Comparison between estimates obtained by the proposed method and observations from LBA towers showed errors between 12.5% and 16.4% and 11.3% and 15.9% for instantaneous and daily Rn, respectively. Our approach was adequate to minimize the problem related to strong cloudiness over the region and allowed to map consistently the spatial distribution of net radiation components in Amazonia. We conclude that the integration of reanalysis products and satellite data, eliminating the need for surface measurements as input model, was a useful proposition for the spatialization of the radiation fluxes in the Amazon region, which may serve as input information needed by algorithms that aim to determine evapotranspiration, the most important component of the Amazon hydrological balance.

  3. A multilayer physically based snowpack model simulating direct and indirect radiative impacts of light-absorbing impurities in snow

    Science.gov (United States)

    Tuzet, Francois; Dumont, Marie; Lafaysse, Matthieu; Picard, Ghislain; Arnaud, Laurent; Voisin, Didier; Lejeune, Yves; Charrois, Luc; Nabat, Pierre; Morin, Samuel

    2017-11-01

    Light-absorbing impurities (LAIs) decrease snow albedo, increasing the amount of solar energy absorbed by the snowpack. Its most intuitive and direct impact is to accelerate snowmelt. Enhanced energy absorption in snow also modifies snow metamorphism, which can indirectly drive further variations of snow albedo in the near-infrared part of the solar spectrum because of the evolution of the near-surface snow microstructure. New capabilities have been implemented in the detailed snowpack model SURFEX/ISBA-Crocus (referred to as Crocus) to account for impurities' deposition and evolution within the snowpack and their direct and indirect impacts. Once deposited, the model computes impurities' mass evolution until snow melts out, accounting for scavenging by meltwater. Taking advantage of the recent inclusion of the spectral radiative transfer model TARTES (Two-stream Analytical Radiative TransfEr in Snow model) in Crocus, the model explicitly represents the radiative impacts of light-absorbing impurities in snow. The model was evaluated at the Col de Porte experimental site (French Alps) during the 2013-2014 snow season against in situ standard snow measurements and spectral albedo measurements. In situ meteorological measurements were used to drive the snowpack model, except for aerosol deposition fluxes. Black carbon (BC) and dust deposition fluxes used to drive the model were extracted from simulations of the atmospheric model ALADIN-Climate. The model simulates snowpack evolution reasonably, providing similar performances to our reference Crocus version in terms of snow depth, snow water equivalent (SWE), near-surface specific surface area (SSA) and shortwave albedo. Since the reference empirical albedo scheme was calibrated at the Col de Porte, improvements were not expected to be significant in this study. We show that the deposition fluxes from the ALADIN-Climate model provide a reasonable estimate of the amount of light-absorbing impurities deposited on the

  4. RadNet Air Data From Fort Smith, AR

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Fort Smith, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  5. RadNet Air Data From Little Rock, AR

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Little Rock, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  6. RadNet Air Data From Mason City, IA

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Mason City, IA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  7. Radiation Synthesis and Characterization of Natural and Natural-Synthetic Hybrid Super Absorbent Polymers for Agricultural Applications. Chapter 19

    Energy Technology Data Exchange (ETDEWEB)

    Şen, M.; Hayrabolulu, H.; Güven, O. [Hacettepe University Department of Chemistry, Beytepe, Ankara (Turkey)

    2014-07-15

    The experimental studies carried out in Hacettepe University, Laboratories of Radiation and Polymers Science (LRPS) in the past ten years, which focused mainly on the synthesis of synthetic and natural-synthetic super absorbent polymers in various irradiation conditions, are summarized in the first part of the presentation. Studies conducted on the following areas: (1) the controlled release of fertilizers and herbicides and the effect of the natural polymer type, (2) the neutralization degree of poly(acrylic acid), (3) the temperature and pressure on the swelling kinetics, and (4) the maximum water absorption capacity of the potential soil conditional hydrogels, were explained. The results were then compared with those obtained from commercial super absorbent polymers prepared through conventional techniques. In the third part of the presentation, basic and advanced techniques in the characterization of the network structure of super water absorbents were presented. (author)

  8. Quantifying the Contributions of Environmental Parameters to Ceres Surface Net Radiation Error in China

    Science.gov (United States)

    Pan, X.; Yang, Y.; Liu, Y.; Fan, X.; Shan, L.; Zhang, X.

    2018-04-01

    Error source analyses are critical for the satellite-retrieved surface net radiation (Rn) products. In this study, we evaluate the Rn error sources in the Clouds and the Earth's Radiant Energy System (CERES) project at 43 sites from July in 2007 to December in 2007 in China. The results show that cloud fraction (CF), land surface temperature (LST), atmospheric temperature (AT) and algorithm error dominate the Rn error, with error contributions of -20, 15, 10 and 10 W/m2 (net shortwave (NSW)/longwave (NLW) radiation), respectively. For NSW, the dominant error source is algorithm error (more than 10 W/m2), particularly in spring and summer with abundant cloud. For NLW, due to the high sensitivity of algorithm and large LST/CF error, LST and CF are the largest error sources, especially in northern China. The AT influences the NLW error large in southern China because of the large AT error in there. The total precipitable water has weak influence on Rn error even with the high sensitivity of algorithm. In order to improve Rn quality, CF and LST (AT) error in northern (southern) China should be decreased.

  9. Effect of gamma radiation on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa

    International Nuclear Information System (INIS)

    Martin Moreno, C.; Fernandez Gonzalez, J.

    1983-01-01

    The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first b chlorophyll affected to a greater extent than a chlorophyll. Net photosynthesis and respiration decline throughout the time of the observation after irradiation, this depressing effect being much more remarkable for the first one. Met photosynthesis inhibition levels of about 30% are got only five hours post irradiation at a dose of 5000 Gy. Radio estimation by low doses, although obtained in some cases for tho 10 Gy dose, has not been statistically confirmed. (Author) 23 refs

  10. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment

    International Nuclear Information System (INIS)

    Barbosa, Isvania Maria Serafim da Silva

    2003-02-01

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with 60 Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  11. Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature?

    International Nuclear Information System (INIS)

    Lin Bing; Min Qilong; Sun Wenbo; Hu Yongxiang; Fan, Tai-Fang

    2011-01-01

    Increasing the knowledge in climate radiative feedbacks is critical for current climate studies. This work focuses on short-term relationships between global mean surface temperature and top-of-atmosphere (TOA) net radiation. The relationships may be used to characterize the climate feedback as suggested by some recent studies. As those recent studies, an energy balance model with ocean mixed layer and both radiative and non-radiative heat sources is used here. The significant improvement of current model is that climate system memories are considered. Based on model simulations, short-term relationship between global mean surface temperature and TOA net radiation (or the linear striation feature as suggested by previous studies) might represent climate feedbacks when the system had no memories. However, climate systems with the same short-term feedbacks but different memories would have a similar linear striation feature. This linear striation feature reflects only fast components of climate feedbacks and may not represent the total climate feedback even when the memory length of climate systems is minimal. The potential errors in the use of short-term relationships in estimations of climate sensitivity could be big. In short time scales, fast climate processes may overwhelm long-term climate feedbacks. Thus, the climate radiative feedback parameter obtained from short-term data may not provide a reliable estimate of climate sensitivity. This result also suggests that long-term observations of global surface temperature and TOA radiation are critical in the understanding of climate feedbacks and sensitivities.

  12. Electrical Conductivity of Gamma Irradiated Aqueous Urea Solution and its Application for Determination of Absorbed Radiation Dose; Sife-Eldeen Dosimeter

    International Nuclear Information System (INIS)

    Sife- Eldeen, Kh.A.

    2008-01-01

    In This Study, the radiation induced electrical conductivity (RIC) of aqueous urea solutions was investigated after gamma radiolysis. It was found that the RIC depends on preirradiation urea concentration, absorbed radiation dose and storage time. At the same absorbed dose, RIC increases as preirradiation urea concentration increases. The RIC change of aqueous urea solutions reaches a maximum value at 3.5 M aqueous urea solutions. RIC of 0.133 and 3.5 M aqueous urea solutions as a function of dose, have been investigated in the range between 2.18 and 119.4 kGy. RIC of the 0.133 and 3.5 M aqueous urea solutions increased linearly with increasing dose (R 2 =0.9963, 0.9972 respectively). The calibration factors was found to be 2.1448 and 9.53 μS/kGy for sets with 0.133 and 3.5 M urea respectively .The coefficient of variation CV %, associated with RIC measurement of 3.5 M aqueous urea solution as a function of absorbed radiation dose was found to be 1.8025% and the uncertainty was found to be 3.6 % and 5.4 % for 95 % and 99 % confidence levels, respectively. The effective atomic number of 3.5 M aqueous urea solutions is 6.58, which indicates tissue equivalency of this system. The RIC values of 3.5 M aqueous urea solutions were found to be relatively stable over storage period of three weeks at 0 degree C. Accordingly, this system could be considered as a promising radiation-sensitive material for dosimetry of gamma rays in both technical and research fields

  13. Effect of UV-B radiation on UV absorbing compounds and pigments of moss and lichen of Schirmacher oasis region, East Antarctica.

    Science.gov (United States)

    Singh, J; Gautam, S; Bhushan Pant, A

    2012-12-22

    The survival of Antarctic flora under ozone depletion depends on their ability to acclimate against increasing UV—B radiation by employing photo protective mechanisms either by avoiding or repairing UV—B damage. A fifteen days experiment was designed to study moss (Bryum argenteum) and lichen (Umbilicaria aprina) under natural UV—B exposure and under UV filter frames at the Maitri region of Schirmacher oasis, East Antarctica. Changes in UV absorbing compounds, phenolics, carotenoids and chlorophyll content were studied for continuous fifteen days and significant changes were observed in the UV exposed plants of B. argenteum and U. aprina. The change in the UV absorbing compounds was more significant in B. argenteum (P<0.0001) than U. aprina (P<0.0002). The change in phenolic contents and total carotenoid content was significant (P<0.0001) in both B. argenteum and lichen U. aprina indicating that the increase in UV absorbing compounds, phenolic contents and total carotenoid content act as a protective mechanism against the deleterious effect of UV—B radiations.

  14. Finite volume method for radiative heat transfer in an unstructured flow solver for emitting, absorbing and scattering media

    International Nuclear Information System (INIS)

    Gazdallah, Moncef; Feldheim, Véronique; Claramunt, Kilian; Hirsch, Charles

    2012-01-01

    This paper presents the implementation of the finite volume method to solve the radiative transfer equation in a commercial code. The particularity of this work is that the method applied on unstructured hexahedral meshes does not need a pre-processing step establishing a particular marching order to visit all the control volumes. The solver simply visits the faces of the control volumes as numbered in the hexahedral unstructured mesh. A cell centred mesh and a spatial differencing step scheme to relate facial radiative intensities to nodal intensities is used. The developed computer code based on FVM has been integrated in the CFD solver FINE/Open from NUMECA Int. Radiative heat transfer can be evaluated within systems containing uniform, grey, emitting, absorbing and/or isotropically or linear anisotropically scattering medium bounded by diffuse grey walls. This code has been validated for three test cases. The first one is a three dimensional rectangular enclosure filled with emitting, absorbing and anisotropically scattering media. The second is the differentially heated cubic cavity. The third one is the L-shaped enclosure. For these three test cases a good agreement has been observed when temperature and heat fluxes predictions are compared with references taken, from literature.

  15. Supplementary comparison CCRI(I)-S2 of standards for absorbed dose to water in 60Co gamma radiation at radiation processing dose levels

    DEFF Research Database (Denmark)

    Burns, D. T.; Allisy-Roberts, P. J.; Desrosiers, M. F.

    2011-01-01

    Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized...... by the Bureau International des Poids et Mesures, who also participated at the lowest dose level using their radiotherapy-level standard for the same quantity. The national standards are in general agreement within the standard uncertainties, which are in the range from 1 to 2 parts in 102. Evidence of a dose...

  16. The Australian Commonwealth standard of measurement for absorbed radiation dose

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1990-06-01

    This report documents the absorbed dose standard for photon beams in the range from 1 to 25 MeV. Measurements of absorbed dose in graphite irradiated by a beam of cobalt-60 gamma rays from an Atomic Energy of Canada Limited (AECL) E1 Dorado 6 teletherapy unit are reported. The measurements were performed using a graphite calorimeter, which is the primary standard for absorbed dose. The measurements are used to calibrate a working standard ion chamber in terms of absorbed dose in graphite. Details of the methods, results and correction factors applied are given in Appendices. 13 refs., 6 tabs., 6 figs

  17. Simulated mixed absorbers and effective atomic numbers for γ ...

    Indian Academy of Sciences (India)

    Keywords. γ-rays; γ attenuation; simulated mixed absorbers; effective atomic ... We have tried to simulate composite (mixed) absorbers ... Experimental method .... puter, Program manual, Centre for Radiation Research, National Bureau of ...

  18. Dynamic response of the thermometric net radiometer

    Science.gov (United States)

    J. D. Wilson; W. J. Massman; G. E. Swaters

    2009-01-01

    We computed the dynamic response of an idealized thermometric net radiometer, when driven by an oscillating net longwave radiation intended roughly to simulate rapid fluctuations of the radiative environment such as might be expected during field use of such devices. The study was motivated by curiosity as to whether non-linearity of the surface boundary conditions...

  19. Analysis of solar water heater with parabolic dish concentrator and conical absorber

    Science.gov (United States)

    Rajamohan, G.; Kumar, P.; Anwar, M.; Mohanraj, T.

    2017-06-01

    This research focuses on developing novel technique for a solar water heating system. The novel solar system comprises a parabolic dish concentrator, conical absorber and water heater. In this system, the conical absorber tube directly absorbs solar radiation from the sun and the parabolic dish concentrator reflects the solar radiations towards the conical absorber tube from all directions, therefore both radiations would significantly improve the thermal collector efficiency. The working fluid water is stored at the bottom of the absorber tubes. The absorber tubes get heated and increases the temperature of the working fluid inside of the absorber tube and causes the working fluid to partially evaporate. The partially vaporized working fluid moves in the upward direction due to buoyancy effect and enters the heat exchanger. When fresh water passes through the heat exchanger, temperature of the vapour decreases through heat exchange. This leads to condensation of the vapour and forms liquid phase. The working fluid returns to the bottom of the collector absorber tube by gravity. Hence, this will continue as a cyclic process inside the system. The proposed investigation shows an improvement of collector efficiency, enhanced heat transfer and a quality water heating system.

  20. Improved netting

    International Nuclear Information System (INIS)

    Bramley, A.; Clabburn, R.J.T.

    1976-01-01

    A method is described for producing netting composed of longitudinal and transverse threads of irradiation cross linked thermoplastic material, the threads being joined together at their crossings by moulded masses of cross linked thermoplastic material. The thread may be formed of polyethylene filaments, subjected to a radiation dose of 15 to 25 MR. The moulding can be conducted at 245 0 to 260 0 C or higher. The product is claimed to be an improved quality of netting, with bonds of increased strength between crossing threads. (U.K.)

  1. Fast neutron radiation inactivation of Bacillus subtilis: Absorbed dose determination

    International Nuclear Information System (INIS)

    Song Lingli; Zheng Chun; Ai Zihui; Li Junjie; Dai Shaofeng

    2011-01-01

    In this paper, fast neutron inactivation effects of Bacillus subtilis were investigated with fission fast neutrons from CFBR-II reactor of INPC (Institute of Nuclear Physics and Chemistry) and mono-energetic neutrons from the Van de Graaff accelerator at Peking University. The method for determining the absorbed dose in the Bacillus subtilis suspension contained in test tubes is introduced. The absorbed dose, on account of its dependence on the volume and the form of confined state, was determined by combined experiments and Monte Carlo method. Using the calculation results of absorbed dose, the fast neutron inactivation effects on Bacillus subtilis were studied. The survival rates and absorbed dose curve was constructed. (authors)

  2. Measuring the absorbed radioactivity during a flight

    International Nuclear Information System (INIS)

    2002-01-01

    This paper presents the new system SIEVERT developed by the General Direction of the Civil Aviation (DGAC) to measure the radiations doses absorbed from cosmic radiation. The system is available on the Internet site: www.sievert-system.org. (A.L.B.)

  3. Single interval longwave radiation scheme based on the net exchanged rate decomposition with bracketing

    Czech Academy of Sciences Publication Activity Database

    Geleyn, J.- F.; Mašek, Jan; Brožková, Radmila; Kuma, P.; Degrauwe, D.; Hello, G.; Pristov, N.

    2017-01-01

    Roč. 143, č. 704 (2017), s. 1313-1335 ISSN 0035-9009 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : numerical weather prediction * climate models * clouds * parameterization * atmospheres * formulation * absorption * scattering * accurate * database * longwave radiative transfer * broadband approach * idealized optical paths * net exchanged rate decomposition * bracketing * selective intermittency Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 3.444, year: 2016

  4. Preparation and characterization of super absorbent polymer from sugarcane bagasse

    International Nuclear Information System (INIS)

    Wiwien Andriyanti; Suyanti; Ngasifudin

    2012-01-01

    Sugarcane bagasse is a source of biomass which large enough numbers and has not been fully exploited. At this time has developed a super absorbent polymer material of sugarcane bagasse that can absorb water up to several times of its own weight and keep this water. Super absorbent polymers can be used as a soil conditioner that can be used as an absorber and storage of ground water, the giver of nutrients for plants, and can improve soil properties. The purpose of this study is to make and characterization of super absorbent polymer (PCS) from sugarcane bagasse. Preparation of super absorbent polymers (PCS) has been done by grafting method using ionizing radiation from Electron Beam Engineering (MBE) 350 mA keV/10. Irradiation process carried out with a dose variation of 20, 35, and 50 kGy. Increasing doses of radiation will increase the percentage fraction of transplantation (grafting) and the fraction of water absorption ability (swelling ratio). (author)

  5. Fractal characteristics correlation between the solar total radiation and net radiation on the apple tree canopy

    International Nuclear Information System (INIS)

    Meng Ping; Zhang Jingsong

    2005-01-01

    The characteristics correlation between solar total radiations(Q) and net radiation(R n) on the apple tree canopy at mainly growth stage in the hilly of Taihang Mountain are analyzed with fractal theory based on regression analysis. The results showed that:1)Q and R n had good liner correlation. The regression function was as the following:R n=0.740 8Q-32.436, which coefficient r is 0.981 1(n=26 279), F cal= 343 665.2 F 0.01 36 277=6.63; 2)The fractal dimension curves of Q and R n both had two no s caling regions, which circumscription time value of the inflexion was 453 and 441 minutes respectively.In the first region, fractal dimensions of Q and R n was 1.112 6, 1.131 9 respectively,and 1.913 6@@@ 1.883 4 in the second region.Those information showed that fractal characteristics of Q and R n is similar. So R n can be calculated with Q on the apple tree canopy

  6. A comparison of Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation.

    Science.gov (United States)

    Shortt, K R; Huntley, R B; Kotler, L H; Boas, J F; Webb, D V

    2006-06-01

    Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation have been compared using transfer standard ionization chambers of types NE 2561 and NE 2611A. Whilst the primary standards of air kerma are similar, both being thick-walled graphite cavity chambers but employing different methods to evaluate the Awall correction, the primary standards of absorbed dose to water are quite different. The Australian standard is based on measurements made with a graphite calorimeter, whereas the Canadian standard uses a sealed water calorimeter. The comparison result, expressed as a ratio of calibration coefficients R=N(ARPANSA)/N(NRC), is 1.0006 with a combined standard uncertainty of 0.35% for the air kerma standards and 1.0052 with a combined standard uncertainty of 0.47% for the absorbed dose to water standards. This demonstrates the agreement of the Australian and Canadian radiation dosimetry standards. The results are also consistent with independent comparisons of each laboratory with the BIPM reference standards. A 'trilateral' analysis confirms the present determination of the relationship between the standards, within the 0.09% random component of the combined standard uncertainty for the three comparisons.

  7. Absorbed dose by a CMOS in radiotherapy

    International Nuclear Information System (INIS)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L. C.

    2011-10-01

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  8. Estimating net ecosystem exchange of carbon using the normalized difference vegetation index and an ecosystem model

    International Nuclear Information System (INIS)

    Veroustraete, F.; Patyn, J.; Myneni, R.B.

    1996-01-01

    The evaluation and prediction of changes in carbon dynamics at the ecosystem level is a key issue in studies of global change. An operational concept for the determination of carbon fluxes for the Belgian territory is the goal of the presented study. The approach is based on the integration of remotely sensed data into ecosystem models in order to evaluate photosynthetic assimilation and net ecosystem exchange (NEE). Remote sensing can be developed as an operational tool to determine the fraction of absorbed photosynthetically active radiation (feAR). A review of the methodological approach of mapping fPAR dynamics at the regional scale by means of NOAA11-A VHRR / 2 data for the year 1990 is given. The processing sequence from raw radiance values to fPAR is presented. An interesting aspect of incorporating remote sensing derived fPAR in ecosystem models is the potential for modeling actual as opposed to potential vegetation. Further work should prove whether the concepts presented and the assumptions made in this study are valid. (NEE). Complex ecosystem models with a highly predictive value for a specific ecosystem are generally not suitable for global or regional applications, since they require a substantial set of ancillary data becoming increasingly larger with increasing complexity of the model. The ideal model for our purpose is one that is simple enough to be used in global scale modeling, and which can be adapted for different ecosystems or vegetation types. The fraction of absorbed photosynthetically active radiation (fPAR) during the growing season determines in part net photosynthesis and phytomass production (Ruimy, 1995). Remotely measured red and near-infrared spectral reflectances can be used to estimate fPAR. Therefore, a possible approach is to estimate net photosynthesis, phytomass, and NEE from a combination of satellite data and an ecosystem model that includes carbon dynamics. It has to be stated that some parts of the work presented in this

  9. Absorbed dose to water determination with ionization chamber dosimetry and calorimetry in restricted neutron, photon, proton and heavy-ion radiation fields.

    Science.gov (United States)

    Brede, H J; Greif, K-D; Hecker, O; Heeg, P; Heese, J; Jones, D T L; Kluge, H; Schardt, D

    2006-08-07

    Absolute dose measurements with a transportable water calorimeter and ionization chambers were performed at a water depth of 20 mm in four different types of radiation fields, for a collimated (60)Co photon beam, for a collimated neutron beam with a fluence-averaged mean energy of 5.25 MeV, for collimated proton beams with mean energies of 36 MeV and 182 MeV at the measuring position, and for a (12)C ion beam in a scanned mode with an energy per atomic mass of 430 MeV u(-1). The ionization chambers actually used were calibrated in units of air kerma in the photon reference field of the PTB and in units of absorbed dose to water for a Farmer-type chamber at GSI. The absorbed dose to water inferred from calorimetry was compared with the dose derived from ionometry by applying the radiation-field-dependent parameters. For neutrons, the quantities of the ICRU Report 45, for protons the quantities of the ICRU Report 59 and for the (12)C ion beam, the recommended values of the International Atomic Energy Agency (IAEA) protocol (TRS 398) were applied. The mean values of the absolute absorbed dose to water obtained with these two independent methods agreed within the standard uncertainty (k = 1) of 1.8% for calorimetry and of 3.0% for ionometry for all types and energies of the radiation beams used in this comparison.

  10. Wavelength-dependent induction of UV absorbing mycosporine-like amino acids in the red alga Chondrus crispus under natural solar radiation

    NARCIS (Netherlands)

    Krabs, G; Bischof, K; Hanelt, D; Karsten, U; Wiencke, C

    2002-01-01

    Polychromatic response spectra for the induction of UV absorbing mycosporine-like amino acids (MAAs) were calculated after exposing small thalli of the red alga Chondrus crispus under various cut-off filters to natural solar radiation on the North Sea island Helgoland, Germany. The laboratory-grown

  11. Radiation absorbed doses at radiographic examination of third molars.

    Science.gov (United States)

    Rehnmark-Larsson, S; Stenström, B; Julin, P; Richter, S

    1982-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. In the maxilla three, and in the mandible four different projections were used; also an extraoral lateral view. The greatest thyroid dose, 35 muGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. the thyroid dose from an extraoral lateral view with high sensitivity screens was 3.7 muGy. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. The corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50%. the Ekta-Speed film required approximately 40% lower exposure than the Ultra-Speed film. Without shielding the gonadal doses from a complete examination of four third molars were of the same order of magnitude as from a full survey with intraoral films, i.e. 3-7 muGy. A horizontal radiation shield reduced the thyroid doses by between 12 and 46% and the gonadal doses by between 50 and 95%. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses by between 15 and 42% and the gonadal doses by two orders of magnitude.

  12. Effects of UVB radiation on net community production in the upper global ocean

    KAUST Repository

    Garcia-Corral, Lara S.

    2016-08-31

    Aim Erosion of the stratospheric ozone layer together with oligotrophication of the subtropical ocean is leading to enhanced exposure to ultraviolet B (UVB) radiation in ocean surface waters. The impact of increased exposure to UVB on planktonic primary producers and heterotrophs is uncertain. Here we test the null hypothesis that net community production (NCP) of plankton communities in surface waters of the tropical and subtropical ocean is not affected by ambient UVB radiation and extend this test to the global ocean, including the polar oceans and the Mediterranean Sea using previous results. Location We conducted experiments with 131 surface communities sampled during a circumnavigation cruise along the tropical and subtropical ocean and combined these results with 89 previous reports encompassing the Atlantic, Pacific, Arctic and Southern Oceans and the Mediterranean Sea. Methods The use of quartz (transparent to UVB radiation) and borosilicate glass materials (opaque to most UVB) for incubations allowed us to compare NCP between communities where UVB is excluded and those receiving natural UVB radiation. Results We found that NCP varies when exposed to natural UVB radiation compared to those where UVB was removed. NCP of autotrophic communities tended to decrease under natural UVB radiation, whereas the NCP of heterotrophic communities tended to increase. However, these variations showed the opposite trend under higher levels of UVB radiation. Main conclusions Our results suggest that earlier estimates of NCP for surface communities, which were hitherto derived using materials blocking UVB radiation were biased, with the direction and magnitude of this bias depending on the metabolic status of the communities and the underwater penetration of UVB radiation.

  13. PROPERTIES OF QSO METAL-LINE ABSORPTION SYSTEMS AT HIGH REDSHIFTS: NATURE AND EVOLUTION OF THE ABSORBERS AND NEW EVIDENCE ON ESCAPE OF IONIZING RADIATION FROM GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Boksenberg, Alec [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Sargent, Wallace L. W., E-mail: boksy@ast.cam.ac.uk [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2015-05-15

    Using Voigt-profile-fitting procedures on Keck High Resolution Spectrograph spectra of nine QSOs, we identify 1099 C IV absorber components clumped in 201 systems outside the Lyman forest over 1.6 ≲ z ≲ 4.4. With associated Si IV, C II, Si II  and N V where available, we investigate the bulk statistical and ionization properties of the components and systems and find no significant change in redshift for C IV and Si IV while C II, Si II  and N V change substantially. The C IV components exhibit strong clustering, but no clustering is detected for systems on scales from 150 km s{sup –1} out to 50,000 km s{sup –1}. We conclude that the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios, we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find that the generally accepted means of radiative escape by transparent channels from the internal star-forming sites is spectrally not viable for our stronger absorbers. We develop an active scenario based on runaway stars with resulting changes in the efflux of radiation that naturally enable the needed spectral convergence, and in turn provide empirical indicators of morphological evolution in the associated galaxies. Together with a coexisting population of relatively compact galaxies indicated by the weaker absorbers in our sample, the collective escape of radiation is sufficient to maintain the intergalactic medium ionized over the full range 1.9 < z ≲ 4.4.

  14. RadNet Radiological Air Monitoring Network

    International Nuclear Information System (INIS)

    Scott Telofski, J.; Askren, D.R.; Petko, Ch.M.; Fraass, R.G.

    2010-01-01

    The United States Environmental Protection Agency operates a national environmental radiation monitoring program called RadNet. RadNet monitors airborne particulates, precipitation, milk, and drinking water for radiation levels. The primary purpose of the original program in the 1950's and 1960's was to collect and analyze samples in various media to assess the effects of radioactive fallout from above-ground nuclear weapon testing. As above-ground testing diminished in the 1970's, the program, especially the air network, became critical in evaluating effects of other types of nuclear incidents, such as the nuclear reactor accident at Chernobyl, as well as monitoring trends in environmental radioactive contamination. The value of rapid data collection subsequent to such incidents led to the consideration of developing air monitors with radiation detectors and telecommunication equipment for real-time radiation measurement. The strengthened United States homeland security posture after 2001 led to production and installation of the current real-time RadNet air monitors. There are now 118 stationary, continuously operating air monitoring stations and 40 mobile air monitors for site specific monitoring. The stationary air monitors include radiation detectors, meteorological sensors, a high-volume air sampler, and communication devices for hourly data transfers. When unusual levels are detected, scientists download a full sodium iodide detector spectrum for analysis. The real-time data collected by RadNet stationary systems permit rapid identification and quantification of airborne nuclides with sufficient sensitivity to provide critical information to help determine protective actions. The data also may help to rapidly refine long-range radioactive plume models and estimate exposure to the population. This paper provides an overview of the airborne particulate monitoring conducted during above-ground nuclear weapon testing, summarizes the uses of data from the program

  15. The application of Petri nets to failure analysis

    International Nuclear Information System (INIS)

    Liu, T.S.; Chiou, S.B.

    1997-01-01

    Unlike the technique of fault tree analysis that has been widely applied to system failure analysis in reliability engineering, this study presents a Petri net approach to failure analysis. It is essentially a graphical method for describing relations between conditions and events. The use of Petri nets in failure analysis enables to replace logic gate functions in fault trees, efficiently obtain minimal cut sets, and absorb models. It is demonstrated that for failure analysis Petri nets are more efficient than fault trees. In addition, this study devises an alternative; namely, a trapezoidal graph method in order to account for failure scenarios. Examples validate this novel method in dealing with failure analysis

  16. Natural terrestrial radiation exposure in Hong Kong. A survey on environmental gamma absorbed dose rate in air

    International Nuclear Information System (INIS)

    Wong, M.C.; Poon, H.T.; Chan, Y.K.; So, C.K.

    2000-01-01

    Hong Kong is a metropolitan city located on the southern coast of China with a population of some six million. About 90% of the population is concentrated in heavily built-up residential and commercial areas, which accounts for less than 50% of the total area in the territory. Hong Kong Observatory, 134A Nathan Road, Kowloon, Hong Kong, China. In order to understand the spatial variations in the environmental radiation levels in Hong Kong, the Hong Kong Observatory (HKO) in early 1999 conducted a study of the environmental gamma absorbed dose rate in air. The study combined data collected by the HKO radiation monitoring network (RMN) and data from a comprehensive territory-wide radiological survey conducted in January and February 1999. The RMN of ten stations each equipped with a Reuter-Stokes Model RSS-1013 HPIC has been in operation since 1987 to continuously monitor the environmental radiation levels over the territory as part of the emergency monitoring programme for response to nuclear accidents at a nearby nuclear power station. The terrestrial component of the environmental radiation field was estimated by subtracting from the measurements the cosmic contribution, which is determined to be about 39 nGy/h from measurements conducted over two large fresh water reservoirs. The RMN data with the long history was analysed to derive the seasonal variations in the environmental radiation levels. On average the environmental gamma absorbed dose rate in air in January and February is 1.03 times of the annual figure. This seasonal correction was applied to the results of the year 1999 survey. As the radiation field in the heavily built-up areas is enhanced by contribution from buildings, in the territory-wide survey measurements were made both in the open field and built-up areas. The territory of Hong Kong was divided into 42 grid boxes of 5 km x 5 km for open field and 61 grid boxes of 2.5 km x 2.5 km for built-up areas according to the population and land use. A

  17. Absorbed dose by a CMOS in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-10-15

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  18. Digital Alloy Absorber for Photodetectors

    Science.gov (United States)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  19. Absorbed radiation doses in women undergone to PET-CT exams for cancer diagnosis

    International Nuclear Information System (INIS)

    Santana, Priscila do Carmo; Bernardes, Felipe Dias; Mamede, Marcelo; Oliveira, Paulo Marcio Campos de; Silva, Teogenes Augusto da; Mourao FIlho, Arnaldo Prata

    2014-01-01

    The absorbed dose in several organs and the effective dose in patients submitted to PET-CT exams with the radiopharmaceutical 18 F-FDG were assessed. The ICRP-106 biokinetic model and thermoluminescent detectors in a anthropomorphic phantom were used. The use of the PET-CT image acquisition protocol, with the CT protocol for anatomical mapping, showed that 60% of effective dose was from the radiotracer administration, being the effective dose values for a female patient of (5.80 ± 1.57) mSv. In conclusion, patient doses can be reduced by using appropriate imaging acquisition in 18 F-FDG PET-CT examinations and promoting the compliance with the radiation protection principles. (author)

  20. Study the Characterization of Spectral Absorbance on Irradiated Milk Protein

    Science.gov (United States)

    Fohely, F.; Suardi, N.

    2018-04-01

    The milk has been adopted as a structural nature food for a long era since it is containing most of the growth factors, protective agents, and enzymes needed for the body. a few attempts have been conducted to treat the dairy products especially raw milk by the means of ionizing radiation. as its production has been an expanding industry for many years due to the high demands from the consumers worldwide, there is still some doubt about preserving these products by irradiation. In this work, a preliminary effort to describe the influences of ionizing radiation on raw milk’s protein will be devoted to measuring the spectral absorbance of the total protein (after subjected to varied radiation doses) by UV-VIS-NIR spectroscopy analysis. The absorbance spectrum then analyzed based on absorbance spectra of organic compounds. A comparison is made between the effects of different radiation doses to estimate the influence in milk’s structure.

  1. Detection limits of absorbed dose of ionizing radiation in molluscan shells as determined by e.p.r. spectroscopy

    International Nuclear Information System (INIS)

    Stachowicz, W.; Michalik, J.; Burlinska, G.; Sadlo, J.; Dziedzic-Goclawska, A.; Ostrowski, K.

    1995-01-01

    The exposure of waters to ionizing radiation from radionuclides imprisoned in dumped nuclear waste containers, freed in nuclear submarine accidents or released in underwater magma eruptions are difficult to be evaluated by conventional radiometric methods. Ionizing radiation evokes stable paramagnetic centers in crystalline lattice of mineral components in bone skeletons of mammals and fishes as well as in exoskeletons of mollusca. They give rise in e.p.r. to specific, extremely stable signals which are proposed to be applied as indicators of radiation exposure levels. In the present study the e.p.r. detection limits of the dose of ionizing radiation absorbed in shells of fresh water and marine mollusca (selected species) have been estimated. It has been found that with fresh water mollusca the dose of 1-2 Gy can be detected, while the sea water mollusca by one order of magnitude lower, i.e. about 0.1 Gy. (author)

  2. Estimation of Net Radiation in Three Different Plant Functional Types in Korea

    International Nuclear Information System (INIS)

    Kwon, H.J.

    2009-01-01

    Net Radiation (R N ) is the major driving force for biophysical and biogeochemical processes in the terrestrial ecosystems, which is one of the most critical variables in both measurement and modeling. Despite its importance, there are only 10 weather stations conducting R N measurements among the 544 stations operated by Korea Meteorological Administration (KMA; KMA, 2008). The measurement of incoming shortwave radiation (R S ↓) is, however, conducted at 22 stations while that of sunshine duration is conducted at all the manned stations. In this context, the recent research for estimating R N using R S ↓ in Korean peninsula by Kwon (2009) is of great worth. The author used a linear regression and the radiation balance methods. We generally agree with the author that, in terms of simplicity and practicality, both methods show reliable applicability for estimating R N . We noted, however, that the author’s experimental method and analysis need some clarification and improvement, that are addressed in the following perspectives: (1) the use of daily integrated data for regression, (2) the use of measured albedo, (3) the use of linear coefficients for whole year data, (4) methodological improvement, (5) the use of sunshine duration, and (6) the error assessment. (author)

  3. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Energy Technology Data Exchange (ETDEWEB)

    Patara, Lavinia [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel (Germany); Vichi, Marcello; Masina, Simona [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Fogli, Pier Giuseppe [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Manzini, Elisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2012-10-15

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall {approx}0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  4. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    International Nuclear Information System (INIS)

    Patara, Lavinia; Vichi, Marcello; Masina, Simona; Fogli, Pier Giuseppe; Manzini, Elisa

    2012-01-01

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ∼0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  5. Heaving buoys, point absorbers and arrays.

    Science.gov (United States)

    Falnes, Johannes; Hals, Jørgen

    2012-01-28

    Absorption of wave energy may be considered as a phenomenon of interference between incident and radiated waves generated by an oscillating object; a wave-energy converter (WEC) that displaces water. If a WEC is very small in comparison with one wavelength, it is classified as a point absorber (PA); otherwise, as a 'quasi-point absorber'. The latter may be a dipole-mode radiator, for instance an immersed body oscillating in the surge mode or pitch mode, while a PA is so small that it should preferably be a source-mode radiator, for instance a heaving semi-submerged buoy. The power take-off capacity, the WEC's maximum swept volume and preferably also its full physical volume should be reasonably matched to the wave climate. To discuss this matter, two different upper bounds for absorbed power are applied in a 'Budal diagram'. It appears that, for a single WEC unit, a power capacity of only about 0.3 MW matches well to a typical offshore wave climate, and the full physical volume has, unfortunately, to be significantly larger than the swept volume, unless phase control is used. An example of a phase-controlled PA is presented. For a sizeable wave-power plant, an array consisting of hundreds, or even thousands, of mass-produced WEC units is required.

  6. Tumoral fibrosis effect on the radiation absorbed dose of 177Lu-Tyr3-octreotate-gold nanoparticles and 177Lu-Tyr3-octreotate radiopharmaceuticals

    International Nuclear Information System (INIS)

    Zambrano R, O. D.

    2015-01-01

    In this work was comparatively evaluated the effect of tumoral fibrosis in the radiation absorbed dose of the radiopharmaceutical 177 Lu-Tyr 3 -octreotate with and without gold nanoparticles. For this, was used an experimental array of tumoral fibrosis and computer models based on Monte Carlo calculations to simulate tumoral micro environments without fibrosis and with fibrosis. The computer simulation code Penelope (Penetration Energy Loss of Positron and Electrons) and MCNP (Monte Carlo N-particle Transport Code System) which are based on the Monte Carlo methodology were used to create the computer models for the simulation of the transport of particles (emitted by 177 Lu) in the micro environments (without fibrosis and with fibrosis) with the purpose of calculating the radiation absorbed dose in the interstitial space and in the nucleus of cancer cells. The first computational model consisted of multiple concentric spheres (as onion shells) with the radioactive source homogeneously distributed in the shell between 5 and 10 μm in diameter which represents the internalization of the radioactive source into the cell cytoplasm as it occurs in target specific radiotherapy. The concentric spheres were useful to calculate the radiation absorbed dose in depth in the models without fibrosis and with fibrosis. Furthermore, there were constructed other computer models using two different codes that simulate the transport of radiation (Penelope and MCNP). These models consist of seven spheres that represent cancer cells (HeLa cells) of 10 μm in diameter and each one of them contain another smaller sphere in the center that represents the cell nucleus. A comparison was done of the radiation absorbed dose in the nucleus of the cells, calculated with both codes, Penelope and MCNP. The radioactive source ( 177 Lu) used for the simulations was given to the codes by means of a convoluted spectrum of the most important beta particles (high percentage emission). To this spectrum

  7. Absorbed dose determination in kilovoltage X-ray synchrotron radiation using alanine dosimeters.

    Science.gov (United States)

    Butler, D J; Lye, J E; Wright, T E; Crossley, D; Sharpe, P H G; Stevenson, A W; Livingstone, J; Crosbie, J C

    2016-12-01

    Alanine dosimeters from the National Physical Laboratory (NPL) in the UK were irradiated using kilovoltage synchrotron radiation at the imaging and medical beam line (IMBL) at the Australian Synchrotron. A 20 × 20 mm 2 area was irradiated by scanning the phantom containing the alanine through the 1 mm × 20 mm beam at a constant velocity. The polychromatic beam had an average energy of 95 keV and nominal absorbed dose to water rate of 250 Gy/s. The absorbed dose to water in the solid water phantom was first determined using a PTW Model 31014 PinPoint ionization chamber traceable to a graphite calorimeter. The alanine was read out at NPL using correction factors determined for 60 Co, traceable to NPL standards, and a published energy correction was applied to correct for the effect of the synchrotron beam quality. The ratio of the doses determined by alanine at NPL and those determined at the synchrotron was 0.975 (standard uncertainty 0.042) when alanine energy correction factors published by Waldeland et al. (Waldeland E, Hole E O, Sagstuen E and Malinen E, Med. Phys. 2010, 37, 3569) were used, and 0.996 (standard uncertainty 0.031) when factors by Anton et al. (Anton M, Büermann L., Phys Med Biol. 2015 60 6113-29) were used. The results provide additional verification of the IMBL dosimetry.

  8. Estimation of daytime net ecosystem CO2 exchange over balsam fir forests in eastern Canada : combining averaged tower-based flux measurements with remotely sensed MODIS data

    International Nuclear Information System (INIS)

    Hassan, Q.K.; Bourque, C.P.A.; Meng, F-R.

    2006-01-01

    Considerable attention has been placed on the unprecedented increases in atmospheric carbon dioxide (CO 2 ) emissions and associated changes in global climate change. This article developed a practical approach for estimating daytime net CO 2 fluxes generated over balsam fir dominated forest ecosystems in the Atlantic Maritime ecozone of eastern Canada. The study objectives were to characterize the light use efficiency and ecosystem respiration for young to intermediate-aged balsam fir forest ecosystems in New Brunswick; relate tower-based measurements of daytime net ecosystem exchange (NEE) to absorbed photosynthetically active radiation (APAR); use a digital elevation model of the province to enhance spatial calculations of daily photosynthetically active radiation and APAR under cloud-free conditions; and generate a spatial calculation of daytime NEE for a balsam fir dominated region in northwestern New Brunswick. The article identified the study area and presented the data requirements and methodology. It was shown that the seasonally averaged daytime NEE and APAR values are strongly correlated. 36 refs., 2 tabs., 10 figs

  9. Discrete curved ray-tracing method for radiative transfer in an absorbing-emitting semitransparent slab with variable spatial refractive index

    International Nuclear Information System (INIS)

    Liu, L.H.

    2004-01-01

    A discrete curved ray-tracing method is developed to analyze the radiative transfer in one-dimensional absorbing-emitting semitransparent slab with variable spatial refractive index. The curved ray trajectory is locally treated as straight line and the complicated and time-consuming computation of ray trajectory is cut down. A problem of radiative equilibrium with linear variable spatial refractive index is taken as an example to examine the accuracy of the proposed method. The temperature distributions are determined by the proposed method and compared with the data in references, which are obtained by other different methods. The results show that the discrete curved ray-tracing method has a good accuracy in solving the radiative transfer in one-dimensional semitransparent slab with variable spatial refractive index

  10. Silver dichromate - a suitable dosimeter for radiation processing

    International Nuclear Information System (INIS)

    Hoang Hoa Mai; Nguyen Dinh Duong

    1995-01-01

    An aqueous dosimeter system based on solution of silver dichromate in perchloric acid and spectrophotometry analysis was investigated. The optical absorption characteristics of solutions have been studied. The molar extinction coefficients and radiation-yield of the dosimeter solutions were determined. The mechanism of radiation-induced reactions in the solutions is also considered. A formula for calculating the dose based on absorbance measurements is presented. The G-value of dichromate reduction caused by gamma radiation was determined. The value found, 0.397 is close to the values of the other authors. Two solutions with different concentrations of dichromate have been chosen to match two applicable dose ranges. The solution containing 0.5 mM Ag 2 Cr 2 O 7 in 0.1 M HClO 4 is applied to dose range of 1 -12 kGy and the solution with 0.5 mM Ag 2 Cr 2 O 7 and 2.00 mM K 2 Cr 2 O 7 in 0.1 M HClO 4 is applied to dose range of 3 to 50 kGy. It was found that the relationship between net absorbance ΔA and radiation dose, D is essentially linear over expected dose ranges. The calibration curves have been drawn up by using least square method. In routine use for gamma radiation the dosimeter show good accuracy, reproducibility and stability of the response. (author). 10 refs., 4 figs., 3 tabs

  11. Experimental study on the ionizing radiation field in absorbers irradiated by the 0.8 GeV and 1.2 GeV electrons

    International Nuclear Information System (INIS)

    Ambrosimov, V.K.; Kalmykov, N.N.; Kovalenko, G.D.

    1987-01-01

    The measurement results of spatial distribution of aluminium detector energy release and radioactivity in absorbers irradiated by 0.8 and 1.2 GeV electrons are given. Absorbers are made of aluminium, iron and lead, 30x30 cm size across the thickness is about 18 radiation length units. Thermoluminescence dosimeters LiF and radiochromium film dosimeters have been used to measure energy release. Induced activity of 18 F and 24 Na nuclides is determined in aluminium detectors. The experimental data are compared with the results of calculation carried out by the Monte-Carlo method

  12. Long-term changes in net radiation and its components above a pine forest and a grass surface in Germany

    International Nuclear Information System (INIS)

    Kessler, A.; Jaeger, L.

    1999-01-01

    Long-term measurements (1974–1993 and 1996, respectively) of the net radiation (Q), global radiation (G), reflected global radiation (R), long-wave atmospheric radiation (A) and thermal radiation (E) of a pine forest in Southern Germany (index p) and of a grass surface in Northern Germany (index g) are compared. The influence of changes in surface properties is discussed. There are, in the case of the pine stand, forest growth and forest management and in the case of the grass surface, the shifting of the site from a climatic garden to a horizontal roof. Both series of radiant fluxes are analyzed with respect to the influences of the weather (cloudiness, heat advection). To eliminate the different influence of the solar radiation of the two sites, it is necessary to normalize by means of the global radiation G, yielding the radiation efficiency Q/G, the albedo R/G=α and the normalized long-wave net radiation (A+E)/G. Furthermore, the long-term mean values and the long-term trend of yearly mean values are discussed and, moreover, a comparison is made of individual monthly values. Q p is twice as large as Q g . The reason for this is the higher values of G and A above the pine forest and half values of α p compared to α g . E p is only a little greater than E g . The time series of the radiation fluxes show the following trends: Q p declines continuously despite a slight increase of G p . This is mainly due to the long-wave radiation fluxes. The net radiation of the grass surface Q g shows noticeably lower values after the merging of the site. This phenomenon is also dominated by the long-wave radiation processes. Although the properties of both site surfaces alter, E p and E g remain relatively stable. A p and A g show a remarkable decrease however. The reason for this is to be found in a modification of the heat advection, showing a more pronounced impact on the more continentally exposed site (pine forest). Compared to α g , α p shows only a small

  13. 1 Mixing state and absorbing properties of black carbon during Arctic haze

    Science.gov (United States)

    Zanatta, Marco; Gysel, Martin; Eleftheriadis, Kosas; Laj, Paolo; Hans-Werner, Jacobi

    2016-04-01

    concentration from SP2, a mass absorption cross section of 6.0 m2 g-1 was found at a wavelength of 880 nm. Concerning mixing, rBC cores with a dimeter between 170 nm and 280 nm were found to be covered by a layer of non-absorbing material having a median thickness of 50 nm. From Mie calculation, such mixing would lead to an enhancement of absorption of 46% compared to a bare BC core. The aforementioned absorption enhancement would lead to a net decrease of single scattering albedo of the total aerosol of less than 1%. The reliability of Mie approach was confirmed by agreement with observations, while MAC values commonly used in radiative forcing models might lead to discrepancies up to 80%. Our work provides all the major optical properties of total aerosol and BC to minimize the uncertainty of radiative estimations based on a priori assumptions.

  14. A simple formula for the net long-wave radiation flux in the southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Tomasz Zapadka

    2001-09-01

    Full Text Available This paper discusses problems of estimating the net long-wave radiation flux at the sea surface on the basis of easily measurable meteorological quantities (air and sea surface temperatures, near-surface water vapour pressure, cloudiness. Empirical data and existing formulae are compared. Additionally, an improved formula for the southern Baltic region is introduced, with a systematic error of less than 1 W -2 and a statistical error of less than 20 W -2.

  15. The Influence of Distribution Nitrogen Fertilizer Management on Absorbed and Radiation Use Efficiency in Forage Sorghum (Sorghum bicolor L. Moench

    Directory of Open Access Journals (Sweden)

    alireza beheshti

    2017-12-01

    Full Text Available Introduction Dry matter production is a function of photosynthesis active radiation absorption (APAR and radiation use efficiency. Sorghum genotypes are different in total dry matter, but the reason of these different is not clear. Producing dry matter is affected by nitrogen distributing method, but the way of this effectiveness on producing of dry matter in sorghum genotypes is not also specified. This paper focused on evaluation of receiving and absorbing PAR, which is affected by nitrogen usage method in forage sorghum genotypes, and reasons of the differences between these genotypes in production of dry matter. The variation in efficiency of APAR depends on two chemical and morphological characteristics of the vegetation, including canopy nitrogen content (NCANOPY and the canopy average for mass per unit of area (Merea. Material and Methods In order to investigate the cumulative photosynthetically active radiation (CPAR and radiation use efficiency (RUE under distributing of nitrogen side dressing and non-distributing conditions, an experiment was conducted at Khorasan Razavei Agriculture and Natural Resources , Research Center Mashhad , Iran. The statical method was according to spilt plots base on randomized complete block design with three replicates. The main plots were fifteen forage sorghum genotypes (Promising lines kfs1, kfs2, kfs3, kfs6, kfs7, kfs8, kfs9, kfs10, kfs11, kfs12, kfs13, kfs15, kfs16, kfs17, kfs18 and the subplots consisted of distributing of nitrogen side dressing and non-distributing. The samples were obtained 5 times during the growing season for determination of some characteristics including dry matter (TDM, leaf area index (LAI and Photosynthetically active radiation (PAR. Then total dry matter (TDM, cumulative Photosynthetically active radiation (CPAR and radiation use efficiency (RUE were calculated by these traits. Absorbed radiation measured by Sub Scan model SSI-UM-1.05 on five location of each plot on bottom

  16. Radiation absorbed dose to the lens in dacryoscintigraphy with /sup 99m/TcO4-1

    International Nuclear Information System (INIS)

    Robertson, J.S.; Brown, M.L.; Colvard, D.M.

    1979-01-01

    Calculations of the radiation dose to the lens for /sup 99m/TcO 4 - in dacryoscintigraphy are developed in some detail. The results indicate that the absorbed dose to the germinal epithelium of the lens is 2.2 x 10 -5 to 1.4 x 10 -4 rad/μCi (5.9 x 10 -12 to 3.8 x 10 -11 Gy/Bq) /sup 99m/TcO 4 - under physiological conditions. With blockage of the lacrimal drainage apparatus, the dose to the lens could increase to 4 x 10 -3 rad/μCi

  17. Fabrication of selective solar absorbers using pulsed laser deposition

    CSIR Research Space (South Africa)

    Yalisi, B

    2009-06-01

    Full Text Available Selective solar absorbers are devices that have been designed to absorb as much as possible of the solar radiation which is in the wavelength range of 0.3 to 2.5 µm and to minimise thermal emittance in the wavelength range from 2.5µm to the far...

  18. Absorbed dose determination in external beam radiotherapy. An international code of practice for dosimetry based on standards of absorbed dose to water

    International Nuclear Information System (INIS)

    2000-01-01

    The International Atomic Energy Agency published in 1987 an International Code of Practice entitled 'Absorbed Dose Determination in Photon and Electron Beams' (IAEA Technical Reports Series No. 277 (TRS-277)), recommending procedures to obtain the absorbed dose in water from measurements made with an ionization chamber in external beam radiotherapy. A second edition of TRS-277 was published in 1997 updating the dosimetry of photon beams, mainly kilovoltage X rays. Another International Code of Practice for radiotherapy dosimetry entitled 'The Use of Plane-Parallel Ionization Chambers in High Energy Electron and Photon Beams' (IAEA Technical Reports Series No. 381 (TRS-381)) was published in 1997 to further update TRS-277 and complement it with respect to the area of parallel-plate ionization chambers. Both codes have proven extremely valuable for users involved in the dosimetry of the radiation beams used in radiotherapy. In TRS-277 the calibration of the ionization chambers was based on primary standards of air kerma; this procedure was also used in TRS-381, but the new trend of calibrating ionization chambers directly in a water phantom in terms of absorbed dose to water was introduced. The development of primary standards of absorbed dose to water for high energy photon and electron beams, and improvements in radiation dosimetry concepts, offer the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. The dosimetry of kilovoltage X rays, as well as that of proton and heavy ion beams, interest in which has grown considerably in recent years, can also be based on these standards. Thus a coherent dosimetry system based on standards of absorbed dose to water is possible for practically all radiotherapy beams. Many Primary Standard Dosimetry Laboratories (PSDLs) already provide calibrations in terms of absorbed dose to water at the radiation quality of 60 Co gamma rays. Some laboratories have extended calibrations to high energy photon and

  19. Simultaneos determination of absorbed doses due to beta and gamma radiations with CaSO4: Dy produced at Ipen

    International Nuclear Information System (INIS)

    Campos, L.L.; Rosa, L.A.R. da.

    1988-07-01

    Due to the Goiania radiological accident, it was necessary to develop urgently a dosimeter in order to evaluate, simultaneously, beta and gamma absorbed doses, due to 137 Cs radiations. Therefore, the Dosimetric Material Production Laboratory of IPEN developed a simple, practical, light and low cost badge using small thickness (0,20mm) thermoluminescent CaSO 4 : Dy pellets produced by the same laboratory. This pellets are adequate for beta radiation detection. These dosimeters were worn by some IPEN technicians who worked in Goiania city, and were used to evaluate the external and internal contaminations presented by the accident victims interned at the Hospital Naval Marcilio Dias. (author) [pt

  20. Evaluation of absorbed radiation dose in mammography using Monte Carlo simulation; Avaliacao da dose absorvida em mamografia usando simulacao Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruno L.; Tomal, Alessandra [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin

    2016-07-01

    Mammography is the main tool for breast cancer diagnosis, and it is based on the use of X-rays to obtain images. However, the glandular tissue present within the breast is highly sensitive to ionizing radiation, and therefore requires strict quality control in order to minimize the absorbed dose. The quantification of the absorbed dose in the breast tissue can be done by using Monte Carlo simulation, which allows a detailed study of the deposition of energy in different regions of the breast. Besides, the results obtained from the simulation can be associated with experimental data and provide values of dose interest, such as the dose deposited in glandular tissue. (author)

  1. Determination of Radiation Absorbed Dose to Primary Liver Tumors and Normal Liver Tissue Using Post Radioembolization 90Y PET

    Directory of Open Access Journals (Sweden)

    Shyam Mohan Srinivas

    2014-10-01

    Full Text Available Background: Radioembolization with Yttrium-90 (90Y microspheres is becoming a more widely used transcatheter treatment for unresectable hepatocellular carcinoma (HCC. Using post-treatment 90Y PET/CT scans,the distribution of microspheres within the liver can be determined and quantitatively assessesed . We studied the radiation dose of 90Y delivered to liver and treated tumors.Methods: This retrospective study of 56 patients with HCC, including analysis of 98 liver tumors, measured and correlated the dose of radiation delivered to liver tumors and normal liver tissue using glass microspheres (TheraSpheres® to the frequency of complications with mRECIST. 90Y PET/CT and triphasic liver CT scans were used to contour treated tumor and normal liver regions and determine their respective activity concentrations. An absorbed dose factor was used to convert the measured activity concentration (Bq/mL to an absorbed dose (Gy.Results: The 98 studied tumors received a mean dose of 169 Gy (mode 90-120 Gy;range 0-570 Gy. Tumor response by mRECIST criteria was performed for 48 tumors that had follow up scans. There were 21 responders (mean dose 215 Gy and 27 nonresponders (mean dose 167 Gy. The association between mean tumor absorbed dose and response suggests a trend but did not reach statistical significance (p=0.099. Normal liver tissue received a mean dose of 67 Gy (mode 60-70 Gy; range 10-120 Gy. There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p=0.036.Conclusion: Our cohort of patients showed a possible dose response trend for the tumors. Collateral dose to normal liver is nontrivial and can have clinical implications. These methods help us understand whether patient adverse events, treatment success, or treatment failure can be attributed to the dose which the tumor or normal liver received.

  2. Comparison of 37 months global net radiation flux derived from PICARD-BOS over the same period observations of CERES and ARGO

    Science.gov (United States)

    Zhu, Ping; Wild, Martin

    2016-04-01

    The absolute level of the global net radiation flux (NRF) is fixed at the level of [0.5-1.0] Wm-2 based on the ocean heat content measurements [1]. The space derived global NRF is at the same order of magnitude than the ocean [2]. Considering the atmosphere has a negligible effects on the global NRF determination, the surface global NRF is consistent with the values determined from space [3]. Instead of studying the absolute level of the global NRF, we focus on the interannual variation of global net radiation flux, which were derived from the PICARD-BOS experiment and its comparison with values over the same period but obtained from the NASA-CERES system and inferred from the ocean heat content survey by ARGO network. [1] Allan, Richard P., Chunlei Liu, Norman G. Loeb, Matthew D. Palmer, Malcolm Roberts, Doug Smith, and Pier-Luigi Vidale (2014), Changes in global net radiative imbalance 1985-2012, Geophysical Research Letters, 41 (no.15), 5588-5597. [2] Loeb, Norman G., John M. Lyman, Gregory C. Johnson, Richard P. Allan, David R. Doelling, Takmeng Wong, Brian J. Soden, and Graeme L. Stephens (2012), Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty, Nature Geoscience, 5 (no.2), 110-113. [3] Wild, Martin, Doris Folini, Maria Z. Hakuba, Christoph Schar, Sonia I. Seneviratne, Seiji Kato, David Rutan, Christof Ammann, Eric F. Wood, and Gert Konig-Langlo (2015), the energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics, 44 (no.11-12), 3393-3429.

  3. Digital radiation monitor system

    International Nuclear Information System (INIS)

    Quan Jinhu; Zhai Yongchun; Guan Junfeng; Ren Dangpei; Ma Zhiyuan

    2003-01-01

    The article introduced digital radiation monitor system. The contents include: how to use advanced computer net technology to establish equipment net for nuclear facility, how to control and manage measuring instruments on field equipment net by local area net, how to manage and issue radiation monitoring data by internet

  4. Computational design for a wide-angle cermet-based solar selective absorber for high temperature applications

    International Nuclear Information System (INIS)

    Sakurai, Atsushi; Tanikawa, Hiroya; Yamada, Makoto

    2014-01-01

    The purpose of this study is to computationally design a wide-angle cermet-based solar selective absorber for high temperature applications by using a characteristic matrix method and a genetic algorithm. The present study investigates a solar selective absorber with tungsten–silica (W–SiO 2 ) cermet. Multilayer structures of 1, 2, 3, and 4 layers and a wide range of metal volume fractions are optimized. The predicted radiative properties show good solar performance, i.e., thermal emittances, especially beyond 2 μm, are quite low, in contrast, solar absorptance levels are successfully high with wide angular range, so that solar photons are effectively absorbed and infrared radiative heat loss can be decreased. -- Highlights: • Electromagnetic simulation of radiative properties by characteristic matrix method. • Optimization for multilayered W–SiO 2 cermet-based absorber by a Genetic Algorithm. • We propose a successfully high solar performance of solar selective absorber

  5. Validity of the concept of absorbed dose as a physical quantity

    International Nuclear Information System (INIS)

    Tada, Jun-Ichiro; Katoh, Kazuaki.

    1995-01-01

    The concept of the 'absorbed dose' of ionizing radiation is scrutinized from physical point of view. It is shown that the concept and definition of the quantity in the ICRU system is disqualified as a physical quantity and the absorbed dose can not always be a 'measure of cause' in describing causality relation between radiation and effects on matter. The current absorbed dose depends even on the energy that have already been brought out from the matter, contrary to the intention of introducing the quantity. Trials to remove these difficulties are made. However, it is also shown there still exists an essential problem that cannot be solved by improving the formulation. (author)

  6. Comparison of tumour and whole body absorbed doses of 177-Lu-DOTA-TATE and Lu-177-DOTA-NOC treatment in the same patient group

    International Nuclear Information System (INIS)

    Yeyin, N.; Kabasakal, L.; Akyel, R.; Demir, M.; Kanmaz, B.; Ocak, M.; Toklu, T.; Selcuk, N.

    2015-01-01

    Full text of publication follows. Peptide Receptor Radionuclide Therapy (PRRT) with Lu-177 labelled peptides in patients with neuroendocrine tumours (NETs) aroused great interest. An estimation of actual radiation doses to tumours is very important for therapy planning. There are several radiolabelled peptides, which can be used for PRRT with different biological behaviour. Aim: the aim of the study was to compare the tumour and normal organ absorbed doses in patients who have received Lu-177-DOTA-TATE and Lu-177 DOTA-NOC. Materials and methods: study was composed of 20 patients (M/F: 10/10, mean age: 51.5 ± 14.9) with histologically proven inoperable NETs. All patients received Lu-177-DOTA-NOC treatment 6 to 12 weeks after last Lu-177-DOTA-TATE treatment. Dosimetric calculations were performed using MIRD scheme and lesion doses were calculated using post therapy whole body images obtained at 4, 20, 44, and 68 hours after injection. Tumour volumes were determined from CT images. Thirteen blood samples beginning from time zero to 4 days after injection were obtained for bone marrow and whole body dosimetry. Results: There were 53 lesions in Lu-177-DOTA-TATE post-therapy whole body images and 49 lesions in Lu-177 DOTA-NOC post therapy images. Lesions were selected according to lesion delineation and superimposed lesions were excluded. Mean lesion absorbed dose is calculated to be 47.4 ± 53.4 and 42.9 ± 52.8 Gy per 370 MBq for Lu-177-DOTA-TATE and DOTA-NOC respectively (p>0.5). There were significantly higher absorbed doses for kidney and bone marrow after Lu-177-DOTA-NOC treatment as compared to Lu-177-DOTA-TATE treatment, which were 6.9 ± 2.7 vs 3.9 ± 1.7 (p<0.05) and 0.12 ± 0.0 vs 0.10 ± 0.0 (p<0.05) Gy, respectively. There was not any difference in plasma elimination times between two tracers. On the other hand the whole body absorbed dose was significantly higher after Lu-177-DOTA-NOC treatment, which was 0.24 ± 0.07 vs 0.20 ± 0.06 Gy (p<0

  7. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

  8. Some comments on the concept of absorbed dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1998-12-01

    The main physical quantity for the evaluation of the induced effects by radiation ionizing is absorbed dose. ICRU report 51 defines this concept as quantity dε divided by dm, where dε is the mean energy imparted by radiation ionizing to matter of mass dm. However, nothing is said about the average operation concerning the stochastic energy imparted ε. Nevertheless, because considers the sum of all changes of rest mass of the involved nuclei and elementary particles in all interactions which occur within the mass (i.e. nuclear reactions and transformations of elementary particles), the average operation can not be done with an equilibrium statistical operator, rather, this has to be defined with a non-equilibrium statistical operator, therefore, absorbed dose is a function dependent on time. Furthermore, we present a discussion to clarify the equilibrium radiation and charged particle equilibrium within the context of thermodynamic equilibrium. (Author)

  9. Some comments on the concept of absorbed dose

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1998-12-15

    The main physical quantity for the evaluation of the induced effects by radiation ionizing is absorbed dose. ICRU report 51 defines this concept as quantity d{epsilon} divided by dm, where d{epsilon} is the mean energy imparted by radiation ionizing to matter of mass dm. However, nothing is said about the average operation concerning the stochastic energy imparted {epsilon}. Nevertheless, because considers the sum of all changes of rest mass of the involved nuclei and elementary particles in all interactions which occur within the mass (i.e. nuclear reactions and transformations of elementary particles), the average operation can not be done with an equilibrium statistical operator, rather, this has to be defined with a non-equilibrium statistical operator, therefore, absorbed dose is a function dependent on time. Furthermore, we present a discussion to clarify the equilibrium radiation and charged particle equilibrium within the context of thermodynamic equilibrium. (Author)

  10. A new laboratory-scale experimental facility for detailed aerothermal characterizations of volumetric absorbers

    Science.gov (United States)

    Gomez-Garcia, Fabrisio; Santiago, Sergio; Luque, Salvador; Romero, Manuel; Gonzalez-Aguilar, Jose

    2016-05-01

    This paper describes a new modular laboratory-scale experimental facility that was designed to conduct detailed aerothermal characterizations of volumetric absorbers for use in concentrating solar power plants. Absorbers are generally considered to be the element with the highest potential for efficiency gains in solar thermal energy systems. The configu-ration of volumetric absorbers enables concentrated solar radiation to penetrate deep into their solid structure, where it is progressively absorbed, prior to being transferred by convection to a working fluid flowing through the structure. Current design trends towards higher absorber outlet temperatures have led to the use of complex intricate geometries in novel ceramic and metallic elements to maximize the temperature deep inside the structure (thus reducing thermal emission losses at the front surface and increasing efficiency). Although numerical models simulate the conjugate heat transfer mechanisms along volumetric absorbers, they lack, in many cases, the accuracy that is required for precise aerothermal validations. The present work aims to aid this objective by the design, development, commissioning and operation of a new experimental facility which consists of a 7 kWe (1.2 kWth) high flux solar simulator, a radiation homogenizer, inlet and outlet collector modules and a working section that can accommodate volumetric absorbers up to 80 mm × 80 mm in cross-sectional area. Experimental measurements conducted in the facility include absorber solid temperature distributions along its depth, inlet and outlet air temperatures, air mass flow rate and pressure drop, incident radiative heat flux, and overall thermal efficiency. In addition, two windows allow for the direct visualization of the front and rear absorber surfaces, thus enabling full-coverage surface temperature measurements by thermal imaging cameras. This paper presents the results from the aerothermal characterization of a siliconized silicon

  11. Effect of the time spent by the photon in the absorbed state on the time-dependent transfer of radiation

    International Nuclear Information System (INIS)

    Rao, D.M.; Rangarajan, K.E.; Peraiah, A.

    1990-01-01

    The time-dependent transfer equation is derived for a two-level atomic model which takes both bound-bound and bound-free transitions into account. A numerical scheme is proposed for solving the monochromatic time-dependent transfer equation when the time spent by the photon in the absorbed state is significant. The method can be easily extended to solve the problem of time-dependent line formation of the bound-free continuum. It is used here to study three types of boundary conditions of the incident radiation incident on a scattering atmosphere. The quantitative results show that the relaxation of the radiation field depends on the optical depth of the medium and on the ray's angle of emergence. 21 refs

  12. UV sensitivity of planktonic net community production in ocean surface waters

    Science.gov (United States)

    Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-05-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

  13. Measurement of absorbed doses near interfaces, and dose mapping using gas chromic dosimetry media. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Rehim, F; Said, F I.A.; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Atomic Energy Athority, P.O.Box 29 Nasr City, Cairo (Egypt)

    1996-03-01

    Gas chromic dosimetry media is a thin-coated film which has advantages for high-dose radiation dosimetry, and produces high-resolution radiation image for gamma radiation. Therefore, these films were calibrated for the dose range 0.1-50 kGy in terms of increase in absorbance at 600 nm, 400 nm; increase in the area of the absorption spectra in the ranges 395-405 nm and 320-450 nm wave length as a function of absorbed dose in water. The calibrated films were used for measurement of absorbed doses close to metal interface, and dose mapping of the radiation field inside product box during a run for sterilizing surgical gloves at the mega-gamma irradiation facility.7 figs.

  14. Broadband near-infrared metamaterial absorbers utilizing highly lossy metals

    DEFF Research Database (Denmark)

    Ding, Fei; Dai, Jin; Chen, Yiting

    2016-01-01

    Radiation absorbers have increasingly been attracting attention as crucial components for controllable thermal emission, energy harvesting, modulators, etc. However, it is still challenging to realize thin absorbers which can operate over a wide spectrum range. Here, we propose and experimentally...... demonstrate thin, broadband, polarization-insensitive and omnidirectional absorbers working in the near-infrared range. We choose titanium (Ti) instead of the commonly used gold (Au) to construct nano-disk arrays on the top of a silicon dioxide (SiO2) coated Au substrate, with the quality (Q) factor...

  15. Time evolution of photon-pulse propagation in scattering and absorbing media: The dynamic radiative transfer system

    Science.gov (United States)

    Georgakopoulos, A.; Politopoulos, K.; Georgiou, E.

    2018-03-01

    A new dynamic-system approach to the problem of radiative transfer inside scattering and absorbing media is presented, directly based on first-hand physical principles. This method, the Dynamic Radiative Transfer System (DRTS), employs a dynamical system formality using a global sparse matrix, which characterizes the physical, optical and geometrical properties of the material-volume of interest. The new system state is generated by the above time-independent matrix, using simple matrix-vector multiplication for each subsequent time step. DRTS is capable of calculating accurately the time evolution of photon propagation in media of complex structure and shape. The flexibility of DRTS allows the integration of time-dependent sources, boundary conditions, different media and several optical phenomena like reflection and refraction in a unified and consistent way. Various examples of DRTS simulation results are presented for ultra-fast light pulse 3-D propagation, demonstrating greatly reduced computational cost and resource requirements compared to other methods.

  16. Radiation absorbed doses from iron-52, iron-55, and iron-59 used to study ferrokinetics

    International Nuclear Information System (INIS)

    Robertson, J.S.; Price, R.R.; Budinger, T.F.; Fairbanks, V.F.; Pollycove, M.

    1983-01-01

    Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also called idiopathic or hereditary hemochromatosis), pernicious anemia in relapse, iron-deficiency anemia, and polycythemia vera. The Fe-52 doses include the dose from the Mn-52m daughter generated after injection of Fe-52. Special attention has been given to the dose to the spleen, which has a relatively high concentration of RBCs and therefore of radioiron, and which varies significantly in size in both health and disease

  17. Engineering calculations in radiative heat transfer

    CERN Document Server

    Gray, W A; Hopkins, D W

    1974-01-01

    Engineering Calculations in Radiative Heat Transfer is a six-chapter book that first explains the basic principles of thermal radiation and direct radiative transfer. Total exchange of radiation within an enclosure containing an absorbing or non-absorbing medium is then described. Subsequent chapters detail the radiative heat transfer applications and measurement of radiation and temperature.

  18. Development of Spectrometer Software for Electromagnetic Radiation Measurement and Analysis

    International Nuclear Information System (INIS)

    Mohd Idris Taib; Noor Ezati Shuib; Wan Saffiey Wan Abdullah

    2013-01-01

    This software was under development using LabVIEW to be using with StellarNet Spectrometer system. StellarNet Spectrometer was supplied with SpectraWiz operating software that can measure spectral data for real-time spectroscopy. This LabVIEW software was used to access real-time data from SpectraWiz dynamic link library as hardware interfacing. This software will acquire amplitude of every electromagnetic wavelength at periodic time. In addition to hardware interfacing, the user interface capabilities of software include plotting of spectral data in various mode including scope, absorbance, transmission and irradiance mode. This software surely can be used for research and development in application, utilization and safety of electromagnetic radiation, especially solar, laser and ultra violet. Of-line capabilities of this software are almost unlimited due to availability of mathematical and signal processing function in the LabVIEW add on library. (author)

  19. Radiation absorbed dose estimates for [1-carbon-11]-glucose in adults: The effects of hyperinsulinemia

    International Nuclear Information System (INIS)

    Powers, W.J.

    1996-01-01

    As preparation for studies of blood-brain glucose transport in diabetes mellitus, radiation absorbed dose estimates from intravenous administration of [1- 11 C]-glucose for 24 internal organs, lens, blood and total body were calculated for three physiologic conditions: euinsulinemic euglycemia, hyperinsulinemic euglycemia and hyperinsulinemic hyperglycemia. Cumulated activities in blood, insulin-independent and insulin-dependent compartments were calculated from blood time-activity curves in normal human volunteers and macaques. Apportionment of cumulated activity to individual organs in insulin-dependent and insulin-independent compartments was based on previously published data. Absorbed doses were calculated with the computer program MIRDOSE 3 for the 70-kg adult phantom. S for blood was calculated separately. The heart wall, lungs and spleen were the organs receiving the highest dose. The effect of hyperinsulinemia was demonstrated by the increase in adsorbed dose to the muscle, heart and blood with a decrease to other internal organs. This effect was more pronounced during hyperinsulinemic hyperglycemia. Hyperinsulinemia produced a decrease in effective dose due to the decrease in cumulated activity in organs with specified weighting factors greater than 0.05. The effective dose per study for [1- 11 C]-glucose is comparable to that reported for 2-deoxy-[2- 18 F]-glucose. 43 refs., 1 fig., 4 tabs

  20. Net greenhouse gas emissions at Eastmain-1 reservoir, Quebec, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Alain; Bastien, Julie; Bonneville, Marie-Claude; del Giorgio, Paul; Demarty, Maud; Garneau, Michelle; Helie, Jean-Francois; Pelletier, Luc; Prairie, Yves; Roulet, Nigel; Strachan, Ian; Teodoru, Cristian

    2010-09-15

    The growing concern regarding the long-term contribution of freshwater reservoirs to atmospheric greenhouse gases (GHG), led Hydro-Quebec, to study net GHG emissions from Eastmain 1 reservoir, which are the emissions related to the creation of a reservoir minus those that would have been emitted or absorbed by the natural systems over a 100-year period. This large study was realized in collaboration with University du Quebec a Montreal, McGill University and Environnement IIlimite Inc. This is a world premiere and the net GHG emissions of EM-1 will be presented in details.

  1. A multi-satellite analysis of the direct radiative effects of absorbing aerosols above clouds

    Science.gov (United States)

    Chang, Y. Y.; Christopher, S. A.

    2015-12-01

    Radiative effects of absorbing aerosols above liquid water clouds in the southeast Atlantic as a function of fire sources are investigated using A-Train data coupled with the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbiting Partnership (Suomi NPP). Both the VIIRS Active Fire product and the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Thermal Anomalies product (MYD14) are used to identify the biomass burning fire origin in southern Africa. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) are used to assess the aerosol type, aerosol altitude, and cloud altitude. We use back trajectory information, wind data, and the Fire Locating and Modeling of Burning Emissions (FLAMBE) product to infer the transportation of aerosols from the fire source to the CALIOP swath in the southeast Atlantic during austral winter.

  2. Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

    2014-07-01

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector.

  3. Validation of a MOSFET dosemeter system for determining the absorbed and effective radiation doses in diagnostic radiology.

    Science.gov (United States)

    Manninen, A-L; Kotiaho, A; Nikkinen, J; Nieminen, M T

    2015-04-01

    This study aimed to validate a MOSFET dosemeter system for determining absorbed and effective doses (EDs) in the dose and energy range used in diagnostic radiology. Energy dependence, dose linearity and repeatability of the dosemeter were examined. The absorbed doses (ADs) were compared at anterior-posterior projection and the EDs were determined at posterior-anterior, anterior-posterior and lateral projections of thoracic imaging using an anthropomorphic phantom. The radiation exposures were made using digital radiography systems. This study revealed that the MOSFET system with high sensitivity bias supply set-up is sufficiently accurate for AD and ED determination. The dosemeter is recommended to be calibrated for energies 80 kVp. The entrance skin dose level should be at least 5 mGy to minimise the deviation of the individual dosemeter dose. For ED determination, dosemeters should be implanted perpendicular to the surface of the phantom to prevent the angular dependence error. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Biodistribution parameters and radiation absorbed dose estimates for radiolabeled human low density lipoprotein

    International Nuclear Information System (INIS)

    Hay, R.V.; Ryan, J.W.; Williams, K.A.; Atcher, R.W.; Brechbiel, M.W.; Gansow, O.A.; Fleming, R.M.; Stark, V.J.; Lathrop, K.A.; Harper, P.V.

    1992-01-01

    The authors propose a model to generate radiation absorbed dose estimates for radiolabeled low density lipoprotein (LDL), based upon eight studies of LDL biodistribution in three adult human subjects. Autologous plasma LDL was labeled with Tc-99m, I-123, or In-111 and injected intravenously. Biodistribution of each LDL derivative was monitored by quantitative analysis of scintigrams and direct counting of excreta and of serial blood samples. Assuming that transhepatic flux accounts for the majority of LDL clearance from the bloodstream, they obtained values of cumulated activity (A) and of mean dose per unit administered activity (D) for each study. In each case highest D values were calculated for liver, with mean doses of 5 rads estimated at injected activities of 27 mCi, 9 mCi, and 0.9 mCi for Tc-99m-LDL, I-123-LDL, and In-111-LDL, respectively

  5. Radiative effects of light-absorbing particles deposited in snow over Himalayas using WRF-Chem simulations

    Science.gov (United States)

    Sarangi, C.; Qian, Y.; Painter, T. H.; Liu, Y.; Lin, G.; Wang, H.

    2017-12-01

    Radiative forcing induced by light-absorbing particles (LAP) deposited on snow is an important surface forcing. It has been debated that an aerosol-induced increase in atmospheric and surface warming over Tibetan Plateau (TP) prior to the South Asian summer monsoon can have a significant effect on the regional thermodynamics and South Asian monsoon circulation. However, knowledge about the radiative effects due to deposition of LAP in snow over TP is limited. In this study we have used a high-resolution WRF-Chem (coupled with online chemistry and snow-LAP-radiation model) simulations during 2013-2014 to estimate the spatio-temporal variation in LAP deposition on snow, specifically black carbon (BC) and dust particles, in Himalayas. Simulated distributions in meteorology, aerosol concentrations, snow albedo, snow grain size and snow depth are evaluated against satellite and in-situ measurements. The spatio-temporal change in snow albedo and snow grain size with variation in LAP deposition is investigated and the resulting shortwave LAP radiative forcing at surface is calculated. The LAP-radiative forcing due to aerosol deposition, both BC and dust, is higher in magnitude over Himalayan slopes (terrain height below 4 km) compared to that over TP (terrain height above 4 km). We found that the shortwave aerosol radiative forcing efficiency at surface due to increase in deposited mass of BC particles in snow layer ( 25 (W/m2)/ (mg/m2)) is manifold higher than the efficiency of dust particles ( 0.1 (W/m2)/ (mg/m2)) over TP. However, the radiative forcing of dust deposited in snow is similar in magnitude (maximum 20-30 W/m2) to that of BC deposited in snow over TP. This is mainly because the amount of dust deposited in snow over TP can be about 100 times greater than the amount of BC deposited in snow during polluted conditions. The impact of LAP on surface energy balance, snow melting and atmospheric thermodynamics is also examined.

  6. Determination of absorbed dose in reactors

    International Nuclear Information System (INIS)

    1971-01-01

    There are many areas in the use and operation of research reactors where the absorbed dose and the neutron fluence are required. These include work on the determination of the radiolytic stability of the coolant and moderator and on the determination of radiation damage in structural materials, and reactor experiments involving radiation chemistry and radiation biology. The requirements range from rough estimates of the total heating due to radiation to precise values specifying the contributions of gamma rays, thermal neutrons and fast neutrons. To meet all these requirements a variety of experimental measurements and calculations as well as a knowledge of reactor radiations and their interactions is necessary. Realizing the complexity and importance of this field, its development at widely separated laboratories and the need to bring the experts in this work together, the IAEA has convened three panel meetings. These were: 'In-pile dosimetry', held in July 1964 (published by the Agency as Technical Reports Series No. 46); 'Neutron fluence measurements', in October 1965; and 'In-pile dosimetry', in November 1966. The recommendations of these three panels led the Agency to form a Working Group on Reactor Radiation Measurements and to commission the writing of this book and a book on Neutron Fluence Measurements. The latter was published in May 1970 (Technical Reports Series No. 107). The material on neutron fluence and absorbed dose measurements is widely scattered in reports and reviews. It was considered that it was time for all relevant information to be evaluated and put together in the form of a practical guide that would be valuable both to experienced workers and beginners in the field

  7. Multilayer detector for measuring absorbed dose in skin

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method of skin dosimetry using multilayer dosimeters is described that allows the skin-depth distribution of absorbed dose to be estimated. A method of quantitative estimation and prediction of the degree of skin radiation damage using a three-layer dosimeter is demonstrated. Dosimeters are holders of tissue-equivalent material that contain photographic film, a scintillator, thermoluminophor, or any other radiation-sensitive element

  8. Calorimeter measurements of absorbed doses at the heavy water enriched uranium reactor

    International Nuclear Information System (INIS)

    Markovic, V.

    1961-12-01

    Application of calorimetry measurements of absorbed doses was imposed by the need of good knowledge of the absorbed dose values in the reactor experimental channels. Other methods are considered less reliable. The work was done in two phases: calorimetry measurements at lower reactor power (13-80 kW) by isothermal calorimeter, and differential calorimeter constructions for measurements at higher power levels (up to 1 MW). This report includes the following four annexes, papers: Isothermal calorimeter for reactor radiation monitoring, to be published; Calorimeter dosimetry of reactor radiation, presented at the Symposium about nuclear fuel held in april 1961; Radiation dosimetry of the reactor RA at Vinca, published in the Bull. Inst. Nucl. Sci. 1961; Differential calorimeter for reactor radiation dosimetry

  9. Absorbed Doses to Embryo from Intravenous Urography at Selected Radiological Departments in Slovakia

    International Nuclear Information System (INIS)

    Karkus, R.; Nikodemova, D.; Horvathova, M.

    2003-01-01

    Actual legislation used in radiological protection requires quality assurance program for decreasing radiation load of patients from radiological examinations. The information about irradiation of pregnant women is very important, because the embryo is more radiosensitive as adult organism. On the basis of absence of unified calculations or measurements of absorbed doses to embryo from various radiological examinations in Slovakia we present in this study the values of absorbed doses to embryo from intravenous urography at selected radiological departments in Slovakia. Absorbed doses to embryo were obtained by measurement and calculation using the simulation of irradiation of pregnant woman by intravenous urography. The results of our study indicate, that absorbed doses to embryo were at various radiological departments considerably different, depending on type of X-ray machine and different settings of technical parameters of X-ray machine. In accordance with worldwide trend it is necessary to decrease radiation load of patients as low as possible level. Differences in radiation load between radiological departments indicate, that it is necessary to continue in solving of this problem and perform measurements and calculations of absorbed doses to embryo at different types of X-ray machines and at different examinations, where the embryo is in direct beam of X-ray. (author)

  10. NOy production, ozone loss and changes in net radiative heating due to energetic particle precipitation in 2002-2010

    Science.gov (United States)

    Sinnhuber, Miriam; Berger, Uwe; Funke, Bernd; Nieder, Holger; Reddmann, Thomas; Stiller, Gabriele; Versick, Stefan; von Clarmann, Thomas; Maik Wissing, Jan

    2018-01-01

    We analyze the impact of energetic particle precipitation on the stratospheric nitrogen budget, ozone abundances and net radiative heating using results from three global chemistry-climate models considering solar protons and geomagnetic forcing due to auroral or radiation belt electrons. Two of the models cover the atmosphere up to the lower thermosphere, the source region of auroral NO production. Geomagnetic forcing in these models is included by prescribed ionization rates. One model reaches up to about 80 km, and geomagnetic forcing is included by applying an upper boundary condition of auroral NO mixing ratios parameterized as a function of geomagnetic activity. Despite the differences in the implementation of the particle effect, the resulting modeled NOy in the upper mesosphere agrees well between all three models, demonstrating that geomagnetic forcing is represented in a consistent way either by prescribing ionization rates or by prescribing NOy at the model top.Compared with observations of stratospheric and mesospheric NOy from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument for the years 2002-2010, the model simulations reproduce the spatial pattern and temporal evolution well. However, after strong sudden stratospheric warmings, particle-induced NOy is underestimated by both high-top models, and after the solar proton event in October 2003, NOy is overestimated by all three models. Model results indicate that the large solar proton event in October 2003 contributed about 1-2 Gmol (109 mol) NOy per hemisphere to the stratospheric NOy budget, while downwelling of auroral NOx from the upper mesosphere and lower thermosphere contributes up to 4 Gmol NOy. Accumulation over time leads to a constant particle-induced background of about 0.5-1 Gmol per hemisphere during solar minimum, and up to 2 Gmol per hemisphere during solar maximum. Related negative anomalies of ozone are predicted by the models in nearly every polar

  11. 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.)

  12. Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase

    International Nuclear Information System (INIS)

    De la Mora, Eugenio; Lovett, Janet E.; Blanford, Christopher F.; Garman, Elspeth F.; Valderrama, Brenda; Rudino-Pinera, Enrique

    2012-01-01

    Radiation-induced reduction, radiolysis of copper sites and the effect of pH value together with the concomitant geometrical distortions of the active centres were analysed in several fungal (C. gallica) laccase structures collected at cryotemperature. This study emphasizes the importance of careful interpretation when the crystallographic structure of a metalloprotein is described. X-ray radiation induces two main effects at metal centres contained in protein crystals: radiation-induced reduction and radiolysis and a resulting decrease in metal occupancy. In blue multicopper oxidases (BMCOs), the geometry of the active centres and the metal-to-ligand distances change depending on the oxidation states of the Cu atoms, suggesting that these alterations are catalytically relevant to the binding, activation and reduction of O 2 . In this work, the X-ray-determined three-dimensional structure of laccase from the basidiomycete Coriolopsis gallica (Cg L), a high catalytic potential BMCO, is described. By combining spectroscopic techniques (UV–Vis, EPR and XAS) and X-ray crystallography, structural changes at and around the active copper centres were related to pH and absorbed X-ray dose (energy deposited per unit mass). Depletion of two of the four active Cu atoms as well as low occupancies of the remaining Cu atoms, together with different conformations of the metal centres, were observed at both acidic pH and high absorbed dose, correlating with more reduced states of the active coppers. These observations provide additional evidence to support the role of flexibility of copper sites during O 2 reduction. This study supports previous observations indicating that interpretations regarding redox state and metal coordination need to take radiation effects explicitly into account

  13. RadNet Air Quality (Deployable) Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet Deployable Monitoring is designed to collect radiological and meteorological information and data asset needed to establish the impact of radiation levels on...

  14. Estimation of Absorbed Dose in Occlusal Radiography

    International Nuclear Information System (INIS)

    Yoo, Young Ah; Choi, Karp Shick; Lee, Sang Han

    1990-01-01

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone ) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  15. Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

    Science.gov (United States)

    Li, Xing; Xiao, Jingfeng; He, Binbin

    2018-04-01

    Amazon forests play an important role in the global carbon cycle and Earth’s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought.

  16. Quality assurance technique for absorbed dose distribution in external radiation therapy with non-physical wedges in consideration of the character of the imaging plate

    International Nuclear Information System (INIS)

    Fujibuchi, Toshioh; Fujisaki, Tatsuya; Kurokawa, Masayuki; Sakae, Takeji

    2011-01-01

    The film dose distribution method is used for profile measurements of non-physical wedges, because three-dimensional automatic control water phantoms cannot be used. Recently, many hospitals have adopted computed radiography (CR) systems in preference to automatic developing processors and films. This may allow use of automatic processors to be discontinued. In this study, a beam was irradiated to an Imaging Plate (IP), and then IP was exposed to a fixed amount of light with fading, and we then measured the off-center ratio (OCR) absorbed dose distribution in external radiation therapy with non-physical wedge. This was compared with the OCR measured with an ionization chamber dosimeter. It was consequently possible for IP to approximate the value measured by the ionization chamber dosimeter by using a metal filter. This method offers a simple quality assurance technique for absorbed dose distribution in external radiation therapy with non-physical wedges in consideration of the character of the IP. (author)

  17. Energy deposition studies for the LBNE beam absorber

    International Nuclear Information System (INIS)

    Rakhno, Igor L.; Mokhov, Nikolai V.; Tropin, Igor S.

    2015-01-01

    Results of detailed Monte Carlo energy deposition studies performed for the LBNE absorber core and the surrounding shielding with the MARS15 code are described. The model of the entire facility that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system - all with corresponding radiation shielding - was developed using the recently implemented ROOT-based geometry option in the MARS15 code. This option provides substantial flexibility and automation when developing complex geometry models. Both normal operation and accidental conditions were studied. Various design options were considered, in particular the following: (i) filling the decay pipe with air or helium; (ii) the absorber mask material and shape; (iii) the beam spoiler material and size. Results of detailed thermal calculations with the ANSYS code helped to select the most viable absorber design options. (authors)

  18. Absorbed radiation to the nuclear medicine nurses from patients administered 201Tl and 99mTc- MIBI

    International Nuclear Information System (INIS)

    Sattari, Ali; Dadashzadeh, Simin; Nasiroghli, G.; Firoozabadi, Hasan

    2008-01-01

    People who have administrated radiopharmaceuticals could be a source of radiation to their relatives, medical nurses, and people who have contact them. In this study, the dose rates at various distances of 5, 10,50 and 100 cm from 70 patients, who were administered diagnostic amounts of 201 Tl -Chloride and 99m Tc -MIBI, was measured using an ionization chamber. For determination of external radiation dose to the nurses the radiations in three deferent interval times have measured. The maximum values of external dose rates of 201 Tl and 99m Tc-MIBI were 11.2μSv/h ±2.3 and 43.1μSv/h ±11.9 respectively at 5 cm from the patients. Significant exposure from patients after injection of 99m Tc -MIBI was limited on the day of administration. Departure doses rate of 201 Tl fell gradually so by 3 days after administration was significant. Maximum and average absorbed dose of nuclear medicine staff for one 201 Tl scan was 4.6 and 2.7μSv/h, and for 99m Tc-MIBI was 18.1 and 9.8μSv/h in a working day. (author)

  19. Synthesis and Characterization of Super absorbent Hydrogels Based on Natural Polymers Using Ionizing Radiations

    International Nuclear Information System (INIS)

    Deghiedy, N.M.A.

    2010-01-01

    Radiation processing technology is a useful tool for modification of polymer material including grafting of monomer onto polymer. In this study, novel super absorbent hydrogels was prepared with biodegradable and eco-friendly properties by graft copolymerization of chitosan and different synthetic monomers (AAc, DEAEMA, HEMA, HPMA and HEA) using gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The different chitosan hydrogels were characterized using FTIR spectroscopy, scanning electron microscopy and thermal analysis techniques. The effects of the preparation conditions on the gelation process of the synthesized copolymer were investigated. The influence of variables such as feed concentration, irradiation dose, composition ratio, ph and temperature on the swelling of the prepared hydrogels was also examined. The water absorbency of these hydrogels in various ph and salt solutions was studied. The swelling kinetics of the prepared hydrogels and in vitro release dynamics of model drug (Chlortetracycline hydrochloride) from these hydrogels has been studied for the evaluation of swelling mechanism and drug release mechanism from the hydrogels. The adsorption and in vitro release profiles of Chlortetracycline HCl from the prepared gels were also estimated in different ph buffers. The amount of drug released from CS/ (AAc-DEAEMA) hydrogels was higher than that released from other modified CS/AAc hydrogels. This preliminary investigation of chitosan based hydrogels showed that they may be exploited to expand the utilization of these systems in drug delivery applications

  20. Full correction of scattering effects by using the radiative transfer theory for improved quantitative analysis of absorbing species in suspensions.

    Science.gov (United States)

    Steponavičius, Raimundas; Thennadil, Suresh N

    2013-05-01

    Sample-to-sample photon path length variations that arise due to multiple scattering can be removed by decoupling absorption and scattering effects by using the radiative transfer theory, with a suitable set of measurements. For samples where particles both scatter and absorb light, the extracted bulk absorption spectrum is not completely free from nonlinear particle effects, since it is related to the absorption cross-section of particles that changes nonlinearly with particle size and shape. For the quantitative analysis of absorbing-only (i.e., nonscattering) species present in a matrix that contains a particulate species that absorbs and scatters light, a method to eliminate particle effects completely is proposed here, which utilizes the particle size information contained in the bulk scattering coefficient extracted by using the Mie theory to carry out an additional correction step to remove particle effects from bulk absorption spectra. This should result in spectra that are equivalent to spectra collected with only the liquid species in the mixture. Such an approach has the potential to significantly reduce the number of calibration samples as well as improve calibration performance. The proposed method was tested with both simulated and experimental data from a four-component model system.

  1. Absorbed Power Minimization in Cellular Users with Circular Antenna Arrays

    Science.gov (United States)

    Christofilakis, Vasilis; Votis, Constantinos; Tatsis, Giorgos; Raptis, Vasilis; Kostarakis, Panos

    2010-01-01

    Nowadays electromagnetic pollution of non ionizing radiation generated by cellular phones concerns millions of people. In this paper the use of circular antenna array as a means of minimizing the absorbed power by cellular phone users is introduced. In particular, the different characteristics of radiation patterns produced by a helical conventional antenna used in mobile phones operating at 900 MHz and those produced by a circular antenna array, hypothetically used in the same mobile phones, are in detail examined. Furthermore, the percentage of decrement of the power absorbed in the head as a function of direction of arrival is estimated for the circular antenna array.

  2. Gamma radiation synthesis of super absorbent hydrogels for different applications

    International Nuclear Information System (INIS)

    Marzouk, H.M.G.

    2015-01-01

    Super absorbent polymers (SAP) of carboxymethyl cellulose/acrylamide (CMC/PAM), carboxymethyl cellulose/acrylamide/Silica (CMC/AM/Si) and carboxymethyl cellulose/Polyvinyl alcohol (CMC/PVA) were synthesized by radiation-induced grafting using γ-irradiation technique. The effects of various parameters, such as irradiation dose, the content of CMC, PAM, PVA, and Silica gel on the swelling percent of produced hydrogels have been evaluated. The kinetic equilibrium swelling of the prepared copolymer hydrogels was studied, it was found that the maximum swelling percent was 5000 % for the CMC/PAM hydrogel, 12000 % for the CMC/PAM/Si composite hydrogel, and 6200 % for the CMC/PVA hydrogel. The gel fraction, equilibrium swelling and effect of ph on the swelling percent were also studied. The prepared copolymers were also characterized by FTIR spectral analysis, thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. In order to evaluate its controlled release potential, different prepared hydrogels were loaded with KNO 3 as an agrochemical model and its potential for controlled release of KNO 3 was studied and evaluated with respect to different parameters such as time of release, ph of the medium, and temperatures. The results obtained from swelling, loading of KNO 3 , and release behavior studies suggested and recommended the possible use of prepared hydrogels for enhancing the plantation of Linum Usitatissimum.

  3. Dental-CT: image quality and absorbed radiation dose of different scan protocols

    International Nuclear Information System (INIS)

    Schorn, C.; Alamo, L.; Funke, M.; Grabbe, E.; Visser, H.; Hermann, K.P.

    1999-01-01

    Purpose: To develop a scan protocol for dental-CT which guarantees good image quality at the lowest possible radiation dose. Methods: In an experimental investigation Dental-CT (HSA, GE, Milwaukee, USA) of the mandible of two human skeletons positioned in a water tank were performed in order to define the most advantageous scan protocol. Tube currents ranged from 40 to 200 mA and the scan technique was modified (axial mode or helical mode with pitches of 1 to 3 and corresponding increments of 0.4 to 1.0 mm). 39 patients underwent a dental-CT with decreased current (80 mA) in the helical scan mode (pitch 2, slice thickness 1 mm). Dose measurements were performed for two different scan protocols (A: axial, 130 mAs, B: helical, 80 mA, pitch 2). Results: The preliminary investigations of image quality showed only a minor effect of the applied current. For the helical scan mode, pitches of more than 2 impaired image quality. A low increment had no advantages. There were no disadvantages in clinical practice using protocol B with decreased tube current. Absorbed radiation dose of dental CT performed with protocol B was decreased to one third in comparison to protocol A. Conclusions: A scan protocol with a low tube current (e.g., 80 mA, for a rotation time of 1 s) and a helical scan mode (e.g., for a slice thickness of 1 mm with a pitch of 2 and an increment of 1 mm) is recommended for performing dental-CT. (orig.) [de

  4. Effect of gamma background on the dose absorbed by human embryon and foetus

    International Nuclear Information System (INIS)

    Miloslavov, V.; Doncheva, B.

    1989-01-01

    A method is proposed for calculation of absorbed radiation dose in different stages of human foetus development under normal or increased gamma background. On the base of ICRP-data for critical organ's mass (foetus, placenta, blood, uterus) a formula is given for absorbed dose evaluation of gonads. It is concluded that increased gamma background is insignificant compared to internal irradiation from absorbed radionuclides

  5. Measurements of a prototype synchrotron radiation pumped absorber for future light sources

    International Nuclear Information System (INIS)

    Chou, T.S.; Foerster, C.L.; Halama, H.; Lanni, C.

    1988-01-01

    In the new generation of advanced synchrotron light sources, the conventional concept of distributed pumping is no longer suitable for removing the gas load caused by photon stimulated desorption (PSD). A new concept using a combination of photon absorber and pumping station has been designed, constructed, and installed in the U1OB beam line at the VUV ring of the National Synchrotron Light Source. The system consists of an electrically insulated water cooled copper block, a titanium sublimation pump, calibrated BA gauges, a calibrated RGA, and a known conductance. A photon beam 10 milliradian wide and 3.26 milliradian high, having critical energy of 500 eV, is directed on the absorber. PSD yield is studied as a function of total beam dose and absorber surface preparation. The results from this experiment, pump characteristics, design of an absorber pump for future light sources, and the pressure improvement factors will be presented. 5 refs., 7 figs., 1 tab

  6. The properties of two starch super absorbent polymers synthesized by gamma radiation

    International Nuclear Information System (INIS)

    Wang Changbao; Zhao Yongfu; Li Lili; Ji Ping; Shi Yan; Ge Cailin; Wang Zhidong

    2013-01-01

    Two types of super absorbent polymers were synthesized from corn starch, wheat starch and acrylic acid under gamma irradiation, without any initiator. The water absorption capacity of the super absorbent products were studied. The results indicated that the prepared polymer from wheat starch per gram could absorb 755 g distilled water, 249 g tap water, and 80 g 0.9% NaCl; and the polymer from corn starch per gram could absorb 747 g distilled water, 238 g tap water, and 84 g 0.9% NaCl. The absorption capacity of the two polymers was decreased quickly at first and then slow down with the concentration of NaCl solutions increased. The two polymers have similar absorption capacity in pH value between 4 and 11 for distilled water and at temperature between 4 and 60℃ for distilled water. The two polymers have good water retention properties in high temperature and pressure conditions. (authors)

  7. Spatial and temporal variations of albedo and absorbed solar radiation during 2009 - 2016 from IKOR-M satellite program

    Science.gov (United States)

    Cherviakov, Maksim; Bogdanov, Mikhail; Spiryakhina, Anastasia; Shishkina, Elena; Surkova, Yana; Kulkova, Eugenia

    2017-04-01

    This report describes Earth's radiation budget IKOR-M satellite program which has been started in Russia. The first satellite "Meteor-M» No 1 of this project was put into orbit in September, 2009. The IKOR-M radiometer is a satellite instrument that measures reflected shortwave radiation (0.3-4.0 µm). It was created in Saratov State University and installed on Russian hydrometeorological satellites "Meteor-M" No 1 and No 2. Radiometer IKOR-M designed for satellite monitoring of the outgoing reflected short-wave radiation, which is one of the components of Earth's radiation budget. Such measurements can be used to derive Earth's surface albedo and absorbed solar radiation. This information also can be used in different models of long-term weather forecasts and in researches of climate change trends (Sklyarov et al., 2016). Satellite "Meteor-M" No 1 and No 2 are heliosynchronous that allows observing from North to South Poles. The basic products of data processing are given in the form of global maps of distribution outgoing short-wave radiation (OSR), albedo and absorbed solar radiation (ASR). Such maps were made for each month during observation period. The IKOR-M product archive is available online at all times. A searchable catalogue of data products is continually updated and users may search and download data products via the Earth radiation balance components research laboratory website (http://www.sgu.ru/structure/geographic/metclim/balans) as soon as they become available. Two series of measurements from two different IKOR-M are available. The first radiometer had worked from October, 2009 to August, 2014 and second - from August, 2014 to the present. Therefore, there is a period when both radiometers work at the same time. Top-of-atmosphere fluxes deduced from the "Meteor-M" No 1 measurements in August, 2014 show very good agreement with the fluxes determined from "Meteor-M" No 2 (Bogdanov et al., 2016). The effect of aging is investigated for first IKOR

  8. Light-absorbing carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions

    Science.gov (United States)

    Carbonaceous aerosols are ubiquitous in the atmosphere and can directly affect Earth’s climate by absorbing and scattering incoming solar radiation. Both field and laboratory measurements have confirmed that biomass burning (BB) is an important primary source of light absorbing o...

  9. Shortwave and longwave radiative contributions to global warming under increasing CO2

    Science.gov (United States)

    Donohoe, Aaron; Armour, Kyle C.; Pendergrass, Angeline G.; Battisti, David S.

    2014-01-01

    In response to increasing concentrations of atmospheric CO2, high-end general circulation models (GCMs) simulate an accumulation of energy at the top of the atmosphere not through a reduction in outgoing longwave radiation (OLR)—as one might expect from greenhouse gas forcing—but through an enhancement of net absorbed solar radiation (ASR). A simple linear radiative feedback framework is used to explain this counterintuitive behavior. It is found that the timescale over which OLR returns to its initial value after a CO2 perturbation depends sensitively on the magnitude of shortwave (SW) feedbacks. If SW feedbacks are sufficiently positive, OLR recovers within merely several decades, and any subsequent global energy accumulation is because of enhanced ASR only. In the GCM mean, this OLR recovery timescale is only 20 y because of robust SW water vapor and surface albedo feedbacks. However, a large spread in the net SW feedback across models (because of clouds) produces a range of OLR responses; in those few models with a weak SW feedback, OLR takes centuries to recover, and energy accumulation is dominated by reduced OLR. Observational constraints of radiative feedbacks—from satellite radiation and surface temperature data—suggest an OLR recovery timescale of decades or less, consistent with the majority of GCMs. Altogether, these results suggest that, although greenhouse gas forcing predominantly acts to reduce OLR, the resulting global warming is likely caused by enhanced ASR. PMID:25385628

  10. Shortwave and longwave radiative contributions to global warming under increasing CO2.

    Science.gov (United States)

    Donohoe, Aaron; Armour, Kyle C; Pendergrass, Angeline G; Battisti, David S

    2014-11-25

    In response to increasing concentrations of atmospheric CO2, high-end general circulation models (GCMs) simulate an accumulation of energy at the top of the atmosphere not through a reduction in outgoing longwave radiation (OLR)—as one might expect from greenhouse gas forcing—but through an enhancement of net absorbed solar radiation (ASR). A simple linear radiative feedback framework is used to explain this counterintuitive behavior. It is found that the timescale over which OLR returns to its initial value after a CO2 perturbation depends sensitively on the magnitude of shortwave (SW) feedbacks. If SW feedbacks are sufficiently positive, OLR recovers within merely several decades, and any subsequent global energy accumulation is because of enhanced ASR only. In the GCM mean, this OLR recovery timescale is only 20 y because of robust SW water vapor and surface albedo feedbacks. However, a large spread in the net SW feedback across models (because of clouds) produces a range of OLR responses; in those few models with a weak SW feedback, OLR takes centuries to recover, and energy accumulation is dominated by reduced OLR. Observational constraints of radiative feedbacks—from satellite radiation and surface temperature data—suggest an OLR recovery timescale of decades or less, consistent with the majority of GCMs. Altogether, these results suggest that, although greenhouse gas forcing predominantly acts to reduce OLR, the resulting global warming is likely caused by enhanced ASR.

  11. Solar radiation on domed roofs

    Energy Technology Data Exchange (ETDEWEB)

    Faghih, Ahmadreza K.; Bahadori, Mehdi N. [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran)

    2009-11-15

    Solar radiation received and absorbed by four domed roofs was estimated and compared with that of a flat roof. The domed roofs all had the same base areas, and equal to that of the flat roof. One of the roofs considered was the dome of the St. Peter's Church in Rome. Compared with the other roofs considered, this dome had a higher aspect ratio. It was found that all domed roofs received more solar radiation than the flat roof. Considering glazed tiles to cover a selected dome in Iran and the dome of the St. Peter's Church, it was found that the solar radiation absorbed by these roofs is reduced appreciably. In the case of the dome of St. Peter's Church, the amount of radiation absorbed was roughly equal to that absorbed by the comparable flat roof in the warm months. In the case of the glazed reference dome located in Yazd, Iran (a city with very high solar radiation), the radiation absorbed was less than that of flat roof at all times. In addition to aesthetics, this may be a reason for employing glazed tiles to cover the domes of all mosques, shrines, and other large buildings in Iran. (author)

  12. Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II).

    Science.gov (United States)

    Deota, P T; Upadhyay, P R; Valodkar, V B

    2003-01-01

    The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

  13. Shining light on radiation detection and energy transfer : Triazole ligands used for detection of radiation and lanthanide binding

    NARCIS (Netherlands)

    Dijkstra, Peter

    2016-01-01

    Some substances, fluorophores, absorb light and then emit that light again as fluorescence. Apart from absorption of light, some of these substances can also emit light after having absorbed energy from radiation. A substance which can absorb radiation and emit the energy as light is called a

  14. Investigation of environmental natural penetrating radiation level in inner mongolia

    International Nuclear Information System (INIS)

    Li Wenyuan; Du Xuelin; Zhang Baozhong; Fu Su; Chen Jun; Zhang Wenhai

    1990-01-01

    The scheme, quality assurance measure, and results for environmental natural penetrating radiation level investigation in Inner Mongolia Autonomous Region was reported. Over the whole Region area of more than 1.18 million km 2 , 1018 net grid measuring points were selected with grid spacing of 25 x 25 km. The range of natural environmental terrestrial γ-radiation air absorbed dose rate over fields was (0.96-18.62) x 10 -8 Gy·h -1 , the range of γ-radiatoin dose rate over road was (1.07-26.08) x 10 -8 Gy·h -1 , the mean was 5.92 x 10 -8 Gy·h -1 ; the range of γ-radiation dose rate in buildings was (3.82-18.94) x 10 -8 Gy·h -1 ; the range of outdoor air absorbed dose rate caused by ionization compnents of cosmic rays was (3.12-5.55) x 10 -8 Gy·h -1 , while indoor range was (2.60-4.66) x 10 -8 Gy·h -1 ; the range of outdoor natural penetrating radiation dose rate was (8.31-11.26) x 10 -8 Gy·h -1 , indoor range was (11.20-14.67) x 10 -8 Gy·h -1 ; annual average individual effective dose equivalent and annual collective effective dose equivalent caused by natural penetrating radiatoin were 0.84 mSv and 1.61 x 10 4 man·Sv respectively. The georgaphical distribution of terrestrial γ-radiation dose rate within all region was reprted, the increase of environmental terrestial γ-radiation caused by human activity was also pointed. This ought to be paid enough attention to

  15. Implementation of a physically-based scheme representing light-absorbing impurities deposition, evolution and radiative impacts in the SURFEX/Crocus model

    Science.gov (United States)

    Tuzet, F.; Dumont, M.; Lafaysse, M.; Hagenmuller, P.; Arnaud, L.; Picard, G.; Morin, S.

    2017-12-01

    Light-absorbing impurities decrease snow albedo, increasing the amount of solar energy absorbed by the snowpack. Its most intuitive impact is to accelerate snow melt. However the presence of a layer highly concentrated in light-absorbing impurities in the snowpack also modify its temperature profile affecting snow metamorphism. New capabilities have been implemented in the detailed snowpack model SURFEX/ISBA-Crocus (referred to as Crocus) to account for impurities deposition and evolution within the snowpack (Tuzet et al., 2017, TCD). Once deposited, the model computes impurities mass evolution until snow melts out. Taking benefits of the recent inclusion of the spectral radiative transfer model TARTES in Crocus, the model explicitly represents the radiative impacts of light-absorbing impurities in snow. In the Pyrenees mountain range, strong sporadic Saharan dust deposition (referred to as dust outbreaks) can occur during the snow season leading some snow layers in the snowpack to contain high concentrations of mineral dust. One of the major events of the past years occurred on February 2014, affecting the whole southern Europe. During the weeks following this dust outbreak a strong avalanche activity was reported in the Aran valley (Pyrenees, Spain). For now, the link between the dust outbreak and the avalanche activity is not demonstrated.We investigate the impact of this dust outbreak on the snowpack stability in the Aran valley using the Crocus model, trying to determine whether the snowpack instability observed after the dust outbreak can be related to the presence of dust. SAFRAN-reanalysis meteorological data are used to drive the model on several altitudes, slopes and aspects. For each slope configuration two different simulations are run; one without dust and one simulating the dust outbreak of February 2014.The two corresponding simulations are then compared to assess the role of impurities on snow metamorphism and stability.On this example, we

  16. Estimating Net Primary Production of Swedish Forest Landscapes by Combining Mechanistic Modeling and Remote Sensing

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Smith, Benjamin; Løfgren, Anders

    2009-01-01

    and the Beer-Lambert law. LAI estimates were compared with satellite-extrapolated field estimates of LAI, and the results were generally acceptable. NPP estimates directly from the dynamic vegetation model and estimates obtained by combining the model estimates with remote sensing information were, on average......The aim of this study was to investigate a combination of satellite images of leaf area index (LAI) with processbased vegetation modeling for the accurate assessment of the carbon balances of Swedish forest ecosystems at the scale of a landscape. Monthly climatologic data were used as inputs...... in a dynamic vegetation model, the Lund Potsdam Jena-General Ecosystem Simulator. Model estimates of net primary production (NPP) and the fraction of absorbed photosynthetic active radiation were constrained by combining them with satellite-based LAI images using a general light use efficiency (LUE) model...

  17. Electron scattering effects on absorbed dose measurements with LiF-dosemeters

    International Nuclear Information System (INIS)

    Bertilsson, G.

    1975-10-01

    The investigation deals with absorbed dose measurements with solid wall-less dosemeters. Electron scattering complicates both measurement of absorbed dose and its theoretical interpretation. The introduction of the dosemeter in a medium causes perturbations of the radiation field. This perturbation and its effect on the distribution of the absorbed dose inside the dosemeter is studied. Plane-parallel LiF-teflon dosemeters (0.005 - 0.1 g.cm -2 ) are irradiated by a photon beam ( 137 Cs) in different media. The investigation shows that corrections must be made for perturbations caused by electron scattering phenomena. Correction factors are given for use in accurate absorbed dose determinations with thermoluminescent dosemeters. (Auth.)

  18. Growth and characterization of CdTe absorbers on GaAs by MBE for high concentration PV solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ari, Ozan; Polat, Mustafa; Selamet, Yusuf [Department of Physics, Izmir Institute of Technology, Izmir 35430 (Turkey); Karakaya, Merve [Department of Material Science and Engineering, Izmir Institute of Technology, Izmir 35430 (Turkey)

    2015-11-15

    CdTe based II-VI absorbers are promising candidates for high concentration PV solar cells with an ideal band gap for AM1.5 solar radiation. In this study, we propose single crystal CdTe absorbers grown on GaAs substrates with a molecular beam epitaxy (MBE) which is a clean deposition technology. We show that high quality CdTe absorber layers can be grown with full width half maximum of X-ray diffraction rocking curves (XRD RC) as low as 227 arc-seconds with 0.5% thickness uniformity that a 2 μm layer is capable of absorbing 99% of AM1.5 solar radiation. Bandgap of the CdTe absorber is found as 1.483 eV from spetroscopic ellipsometry (SE) measurements. Also, high absorption coefficient is calculated from the results, which is ∝5 x 10{sup 5}cm{sup -1} in solar radiation spectrum. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Electrical behavior research of silicon photo-cell used in online monitoring absorbed dose rate of γ-ray

    International Nuclear Information System (INIS)

    Yang Guixia; Li Xiaoyan; Fu Lan; Wu Wenhao; An You; Zeng Fansong

    2015-01-01

    The real-time online monitoring system for γ-ray absorbed dose rate was established to study the relationship between the photocurrent of semi-conductive silicon photo-cell BBZSGD-4 and γ-ray absorbed dose rate under the open circuit. The radioactive experiments in "6"0Co γ radiation field show that photo-cell BBZSGD-4 has good response to "6"0Co γ-ray, and their relationship accords with the linear law. The photocurrent of photo-cell can be up to 1.26 μA when the absorbed dose rate is 94.54 Gy/min. The relationship between photocurrent and the absorbed dose accords with exponential law when absorbed dose rate is 50 Gy/min, and the attenuation of photocurrent is 1% when the absorbed dose is 5445.8 Gy. Thus photo-cell BBZSGD-4 has the potential to be a real-time detector to detect low absorbed dose rate in "6"0Co γ radiation field. (authors)

  20. Transformation method for the MIRD absorbed fractions as applied to various physiques

    International Nuclear Information System (INIS)

    Yamaguchi, Hiroshi

    1978-01-01

    This study concerns with the transformation method of the MIRD absorbed fraction (AF) to the AF corresponding to an individual having the dimensions different from those of the MIRD standard man. The absorbed dose of a target organ T from a source organs S, received by the administration of a radiopharmaceutical agent is expressed with the equilibrium absorbed dose constant, the cumulative activity in the S, and the specific absorbed fraction (SAF). It is dealt only with how the MIRD SAF data can be modified for estimating individual SAF values. The SAF for individuals is given for penetrating and non-penetrating radiations. In case of the penetrating radiation, the SAF is given from the corresponding MIRD SAF by using a transformation coefficient for the MIRD SAF, when the MIRD standard man is transfigured to a corresponding phantom of an individual by the scale factors selected separately for the head section, trunk section and leg section of the MIRD standard man. The obtained results were compared with the ORNL results, and showed good agreement. (Kato, T.)

  1. Multilayer detector for skin absorbed dose measuring

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

  2. Radiation balances of melting snow covers at an open site in the Central Sierra Nevada, California

    International Nuclear Information System (INIS)

    Aguado, E.

    1985-01-01

    The radiation balances of melting snow packs for three seasons at an open site at the Central Sierra Snow Laboratory near Soda Springs, California were examined. The snow covers were examples of below-normal, near-normal and much-above-normal water equivalents. Two of the snow covers melted under generally clear skies in late spring while the other melted under cloudier conditions and at a time when less extraterrestrial radiation was available. Moreover, the snow covers were of very different densities, thereby allowing examination of a possible relationship between that characteristic and albedo. No such relationship was observed. Despite the dissimilarities in the conditions under which melt occurred, the disposition of solar radiation was similar for the three melt seasons. Albedos and their rates of decline through the melt season were similar for the three seasons. Absorbed solar radiation and a cloudiness index were useful predictors for daily net radiation, accounting for 71% of the total variance. (author)

  3. Application of polystyrene - water calorimeter in determination of absorbed dose. Vol. 4.

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, F A [Nuclear Materials Authority, Maadi, Cairo (Egypt); Ashry, H A; El-Behay, A Z; Abdou, S [National Center, for Radiation Research and Technology, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The polystyrene-water calorimeter was investigated as a modification of the water calorimeter, where the polystyrene has a low specific heat and negligible known heat defect. This calorimeter was designed, constructed and calibrated for measurement of radiation absorbed dose. The system utilizes a thermistor to detect the radiation-induced temperature rise in the polystyrene absorber at certain point from the radiation source. A temperature stability of as low as 0.0018 degree C/min in a 42.0 degree C environment, and a gamma-radiation sensitivity of as high as 1.9720 ohm/Gy were obtained. Comparisons of the results obtained by using the polystyrene-water calorimeter with those obtained by applying other types of calorimeters i.e., water and graphite calorimeters were also done to aid in the possible realization of an accurate and efficient instrument for use under widely different irradiation conditions. 4 figs., 1 tab.

  4. Estimating shortwave solar radiation using net radiation and meteorological measurements

    Science.gov (United States)

    Shortwave radiation has a wide variety of uses in land-atmosphere interactions research. Actual evapotranspiration estimation that involves stomatal conductance models like Jarvis and Ball-Berry require shortwave radiation to estimate photon flux density. However, in most weather stations, shortwave...

  5. Direct and semi-direct radiative forcing of smoke aerosols over clouds

    Directory of Open Access Journals (Sweden)

    E. M. Wilcox

    2012-01-01

    Full Text Available Observations from Earth observing satellites indicate that dark carbonaceous aerosols that absorb solar radiation are widespread in the tropics and subtropics. When these aerosols mix with clouds, there is generally a reduction of cloudiness owing to absorption of solar energy in the aerosol layer. Over the subtropical South Atlantic Ocean, where smoke from savannah burning in southern Africa resides above a persistent deck of marine stratocumulus clouds, radiative heating of the smoke layer leads to a thickening of the cloud layer. Here, satellite observations of the albedo of overcast scenes of 25 km2 size or larger are combined with additional satellite observations of clouds and aerosols to estimate the top-of-atmosphere direct radiative forcing attributable to presence of dark aerosol above bright cloud, and the negative semi-direct forcing attributable to the thickening of the cloud layer. The average positive direct radiative forcing by smoke over an overcast scene is 9.2±6.6 W m−2 for cases with an unambiguous signal of absorbing aerosol over cloud in passive ultraviolet remote sensing observations. However, cloud liquid water path is enhanced by 16.3±7.7 g m−2 across the range of values for sea surface temperature for cases of smoke over cloud. The negative radiative forcing associated with this semi-direct effect of smoke over clouds is estimated to be −5.9±3.5 W m−2. Therefore, the cooling associated with the semi-direct cloud thickening effect compensates for greater than 60 % of the direct radiative effect. Accounting for the frequency of occurrence of significant absorbing aerosol above overcast scenes leads to an estimate of the average direct forcing of 1.0±0.7 W m−2 contributed by these scenes averaged over the subtropical southeast Atlantic Ocean during austral winter. The regional average of the negative semi-direct forcing is −0.7±0.4 W m−2

  6. Peculiarities of absorbed dose forming in some wild animals in Chornobyl exclusion zone

    Directory of Open Access Journals (Sweden)

    V. A. Gaychenko

    2015-10-01

    Full Text Available Based on field researches conducted in the exclusion zone of the Chernobyl nuclear power plant in the years after the accident, the peculiarities are identified of formation of absorbed doses in animals of different taxonomic and ecological groups that live in conditions of radioactive contamination of ecosystems. It was shown importance of consideration of radiation features on wild animals according to their life cycle, conditions and ways of life. Data were displayed about the importance of different types of irradiation according to the period of stay of the animals in the ground, in burrows and nests. The questions were reviewed about value of external and internal radiation in absorbed dose of different types of wildlife. Results of the calculation of the absorbed dose of bird embryos from egg shell were shown.

  7. Isoeffective dose: a concept for biological weighting of absorbed dose in proton and heavier-ion therapies

    CERN Document Server

    Wambersie, A; Menzel, H G; Gahbauer, R; DeLuca, P M; Hendry, J H; Jones, D T L

    2011-01-01

    When reporting radiation therapy procedures, International Commission on Radiation Units and Measurements (ICRU) recommends specifying absorbed dose at/in all clinically relevant points and/or volumes. In addition, treatment conditions should be reported as completely as possible in order to allow full understanding and interpretation of the treatment prescription. However, the clinical outcome does not only depend on absorbed dose but also on a number of other factors such as dose per fraction, overall treatment time and radiation quality radiation biology effectiveness (RBE). Therefore, weighting factors have to be applied when different types of treatments are to be compared or to be combined. This had led to the concept of `isoeffective absorbed dose', introduced by ICRU and International Atomic Energy Agency (IAEA). The isoeffective dose D(IsoE) is the dose of a treatment carried out under reference conditions producing the same clinical effects on the target volume as those of the actual treatment. It i...

  8. Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes

    International Nuclear Information System (INIS)

    Sebesta, F.; John, J.; Motl, A.; Stamberg, K.

    1995-11-01

    The chemical and radiation stability of polyacrylonitrile (PAN) in the form of beads (B-PAN), similar to the beads of composite absorbers, and one selected composite absorber (ammonium molybdophosphate, the active component in PAN binder [AMP-PAN], a prospective candidate for the treatment of acidic wastes) were studied. Aqueous 1M HNO 3 + 1M NaNO 3 , 1M NaOH + 1M NaNO 3 , and 1M NaOH were chosen as simulants of DOE acidic and alkaline wastes. In addition,radiation stability was determined indistilled water. The chemical stability of B-PAN and AMP-PAN beads was tested for a period up to one month of contact with the solution at ambient temperature. The radiation stability of the beads was checked in a radiation dose range 10 3 --10 6 Gy (10 5 --10 8 rads). In acidic solutions the stability of PAN binder was proved not to be limited by either chemical or radiation decomposition. PAN binder may thus be used for preparing composite absorbers for treatment of acid wastes from DOE facilities. The same conclusion is valid for alkaline solutions with pH up to 13. In highly alkaline solutions (concentration of NAOH higher than I M) and in the presence of NaNO 3 , the stability of the tested polyacrylonitrile polymer was sufficient for applications not extending over 10 days. Cross-linking of the polymer caused by ionizing radiation was found to have a positive influence on chemical stability. This effect enables a longer period of applicability of PAN-based composite absorbers. Because of the high sorption rate achievable with PAN-based absorbers, the stability achieved is sufficient for most applications in the DOE complex. The chemical stability of binding polymer may also be further improved by testing another, more suitable type of polymer from the broad family of polyacrylonitrile polymers

  9. Absorbed bone marrow dose in certain dental radiographic techniques

    International Nuclear Information System (INIS)

    White, S.C.; Rose, T.C.

    1979-01-01

    The absorbed dose of radiation in the bone marrow of the region of the head and neck was measured during intraoral, panoramic, and cephalometric radiography. Panoramic radiography results in a dose a fifth or less than that from an intraoral survey. The use of rectangular collimation reduces the bone marrow absorbed dose from an intraoral survey by about 60%. Comparison of the doses from dental radiography with natural environmental radiation shows that an intraoral set of films results in the same total dose to the bone marrow as 65 days of background exposure. The use of rectangular collimation reduces this value to 25 days. Panoramic radiography results in significantly less irradiation, as it reduces the value to 14 days or fewer. Dental radiography thus involves exposures in the range of variation of natural environmental background values

  10. Nuclides.net: An integrated environment for computations on radionuclides and their radiation

    International Nuclear Information System (INIS)

    Galy, J.; Magill, J.

    2002-01-01

    Full text: The Nuclides.net computational package is of direct interest in the fields of environment monitoring and nuclear forensics. The 'integrated environment' is a suite of computer programs ranging from a powerful user-friendly interface, which allows the user to navigate the nuclide chart and explore the properties of nuclides, to various computational modules for decay calculations, dosimetry and shielding calculations, etc. The main emphasis in Nuclides.net is on nuclear science applications, such as health physics, radioprotection and radiochemistry, rather than nuclear data for which excellent sources already exist. In contrast to the CD-based Nuclides 2000 predecessor, Nuclides.net applications run over the internet on a web server. The user interface to these applications is via a web browser. Information submitted by the user is sent to the appropriate applications resident on the web server. The results of the calculations are returned to the user, again via the browser. The product is aimed at both students and professionals for reference data on radionuclides and computations based on this data using the latest internet technology. It is particularly suitable for educational purposes in the nuclear industry, health physics and radiation protection, nuclear and radiochemistry, nuclear physics, astrophysics, etc. The Nuclides.net software suite contains the following modules/features: a) A new user interface to view the nuclide charts (with zoom features). Additional nuclide charts are based on spin, parity, binding energy etc. b) There are five main applications: (1) 'Decay Engine' for decay calculations of numbers, masses, activities, dose rates, etc. of parent and daughters. (2) 'Dosimetry and Shielding' module allows the calculation of dose rates from both unshielded and shielded point sources. A choice of 10 shield materials is available. (3) 'Virtual Nuclides' allows the user to do decay and dosimetry and shielding calculations on mixtures of

  11. Performance evaluation of METAMIC neutron absorber in spent fuel storage rack

    Directory of Open Access Journals (Sweden)

    Kiyoung Kim

    2018-06-01

    Full Text Available High-density spent fuel (SF storage racks have been installed to increase SF pool capacity. In these SF racks, neutron absorber materials were placed between fuel assemblies allowing the storage of fuel assemblies in close proximity to one another. The purpose of the neutron absorber materials is to preclude neutronic coupling between adjacent fuel assemblies and to maintain the fuel in a subcritical storage condition. METAMIC neutron absorber has been used in high-density storage racks. But, neutron absorber materials can be subject to severe conditions including long-term exposure to gamma radiation and neutron radiation. Recently, some of them have experienced degradation, such as white spots on the surface. Under these conditions, the material must continue to serve its intended function of absorbing neutrons. For the first time in Korea, this article uses a neutron attenuation test to examine the performance of METAMIC surveillance coupons. Also, scanning electron microscope analysis was carried out to verify the white spots that were detected on the surface of METAMIC. In the neutron attenuation test, there was no significant sign of boron loss in most of the METAMIC coupons, but the coupon with white spots had relatively less B-10 content than the others. In the scanning electron microscope analysis, corrosion material was detected in all METAMIC coupons. Especially, it was confirmed that the coupon with white spots contains much more corrosion material than the others. Keywords: Blister, Criticality, METAMIC, Neutron Absorber, Neutron Attenuation Test, Scanning Electron Microscope

  12. Modification of Sunlight Radiation through Colored Photo-Selective Nets Affects Anthocyanin Profile in Vaccinium spp. Berries.

    Science.gov (United States)

    Zoratti, Laura; Jaakola, Laura; Häggman, Hely; Giongo, Lara

    2015-01-01

    In recent years, the interest on the effects of the specific wavelengths of the light spectrum on growth and metabolism of plants has been increasing markedly. The present study covers the effect of modified sunlight conditions on the accumulation of anthocyanin pigments in two Vaccinium species: the European wild bilberry (V. myrtillus L.) and the cultivated highbush blueberry (V. corymbosum L.). The two Vaccinium species were grown in the same test field in the Alps of Trentino (Northern Italy) under modified light environment. The modification of sunlight radiation was carried out in field, through the use of colored photo-selective nets throughout the berry ripening during two consecutive growing seasons. The anthocyanin profile was then assessed in berries at ripeness. The results indicated that the light responses of the two Vaccinium species studied were different. Although both studied species are shade-adapted plants, 90% shading of sunlight radiation was beneficial only for bilberry plants, which accumulated the highest content of anthocyanins in both seasons. The same condition, instead, was not favorable for blueberries, whose maturation was delayed for at least two weeks, and anthocyanin accumulation was significantly decreased compared to berries grown under sunlight conditions. Moreover, the growing season had strong influence on the anthocyanin accumulation in both species, in relation to temperature flow and sunlight spectra composition during the berry ripening period. Our results suggest that the use of colored photo-selective nets may be a complementary agricultural practice for cultivation of Vaccinium species. However, further studies are needed to analyze the effect of the light spectra modifications to other nutritional properties, and to elucidate the molecular mechanisms behind the detected differences between the two relative Vaccinium species.

  13. Tumoral fibrosis effect on the radiation absorbed dose of {sup 177}Lu-Tyr{sup 3}-octreotate-gold nanoparticles and {sup 177}Lu-Tyr{sup 3}-octreotate radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano R, O. D.

    2015-07-01

    In this work was comparatively evaluated the effect of tumoral fibrosis in the radiation absorbed dose of the radiopharmaceutical {sup 177}Lu-Tyr{sup 3}-octreotate with and without gold nanoparticles. For this, was used an experimental array of tumoral fibrosis and computer models based on Monte Carlo calculations to simulate tumoral micro environments without fibrosis and with fibrosis. The computer simulation code Penelope (Penetration Energy Loss of Positron and Electrons) and MCNP (Monte Carlo N-particle Transport Code System) which are based on the Monte Carlo methodology were used to create the computer models for the simulation of the transport of particles (emitted by {sup 177}Lu) in the micro environments (without fibrosis and with fibrosis) with the purpose of calculating the radiation absorbed dose in the interstitial space and in the nucleus of cancer cells. The first computational model consisted of multiple concentric spheres (as onion shells) with the radioactive source homogeneously distributed in the shell between 5 and 10 μm in diameter which represents the internalization of the radioactive source into the cell cytoplasm as it occurs in target specific radiotherapy. The concentric spheres were useful to calculate the radiation absorbed dose in depth in the models without fibrosis and with fibrosis. Furthermore, there were constructed other computer models using two different codes that simulate the transport of radiation (Penelope and MCNP). These models consist of seven spheres that represent cancer cells (HeLa cells) of 10 μm in diameter and each one of them contain another smaller sphere in the center that represents the cell nucleus. A comparison was done of the radiation absorbed dose in the nucleus of the cells, calculated with both codes, Penelope and MCNP. The radioactive source ({sup 177}Lu) used for the simulations was given to the codes by means of a convoluted spectrum of the most important beta particles (high percentage emission

  14. Radiation absorbed dose and expected risk in head and neck tissues after thyroid radioiodine therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, A [National Center for Nuclear and Radiation Control, AEA., Cairo (Egypt); Farag, H I [National Cancer instiute, Cairo University, Cairo (Egypt); Saleh, A [Al-hussien Hospital, Al-Azhar University, Cairo (Egypt)

    1997-12-31

    Measurement of absorbed dose in head and neck phantom after applying I-131 therapeutic dose for the treatment of thyroid malignancies was conducted. The measurement were carried out at several sites of phantom using TL dosimeters. The absorbed doses were also measured on the skin of four patients during their administration of I-131 therapeutic doses 1.332 GBq (36 mci) I-131. The measurements were taken over 69 hours exposure at different sites of phantom. The same measurements were carried out on the four patients. At five sites of the patients head and neck, the absorbed dose were measured and compared with that measured on the phantom. The values measured are discussed in the light of the published individual absorbed doses in the organs by ICRP tables. High absorbed doses were absorbed in the different sites of the head and neck during the I-131 therapy (0.14-9.68 mGy/mCi). 3 figs., 2 tabs.

  15. NOy production, ozone loss and changes in net radiative heating due to energetic particle precipitation in 2002–2010

    Directory of Open Access Journals (Sweden)

    M. Sinnhuber

    2018-01-01

    Full Text Available We analyze the impact of energetic particle precipitation on the stratospheric nitrogen budget, ozone abundances and net radiative heating using results from three global chemistry-climate models considering solar protons and geomagnetic forcing due to auroral or radiation belt electrons. Two of the models cover the atmosphere up to the lower thermosphere, the source region of auroral NO production. Geomagnetic forcing in these models is included by prescribed ionization rates. One model reaches up to about 80 km, and geomagnetic forcing is included by applying an upper boundary condition of auroral NO mixing ratios parameterized as a function of geomagnetic activity. Despite the differences in the implementation of the particle effect, the resulting modeled NOy in the upper mesosphere agrees well between all three models, demonstrating that geomagnetic forcing is represented in a consistent way either by prescribing ionization rates or by prescribing NOy at the model top.Compared with observations of stratospheric and mesospheric NOy from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS instrument for the years 2002–2010, the model simulations reproduce the spatial pattern and temporal evolution well. However, after strong sudden stratospheric warmings, particle-induced NOy is underestimated by both high-top models, and after the solar proton event in October 2003, NOy is overestimated by all three models. Model results indicate that the large solar proton event in October 2003 contributed about 1–2 Gmol (109 mol NOy per hemisphere to the stratospheric NOy budget, while downwelling of auroral NOx from the upper mesosphere and lower thermosphere contributes up to 4 Gmol NOy. Accumulation over time leads to a constant particle-induced background of about 0.5–1 Gmol per hemisphere during solar minimum, and up to 2 Gmol per hemisphere during solar maximum. Related negative anomalies of ozone are predicted by

  16. Neutron absorbed dose in a pacemaker CMOS

    International Nuclear Information System (INIS)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L.

    2012-01-01

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10 -17 Gy per neutron emitted by the source. (Author)

  17. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-06-15

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  18. No-contact method of determining average working-surface temperature of plate-type radiation-absorbing thermal exchange panels of flat solar collectors for heating heat-transfer fluid

    International Nuclear Information System (INIS)

    Avezova, N.R.; Avezov, R.R.

    2015-01-01

    A brand new no-contact method of determining the average working-surface temperature of plate-type radiation-absorbing thermal exchange panels (RATEPs) of flat solar collectors (FSCs) for heating a heat-transfer fluid (HTF) is suggested on the basis of the results of thermal tests in full-scale quasistationary conditions. (authors)

  19. Radiation risk of tissue late effects, a net consequence of probabilities of various cellular responses

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    1991-01-01

    Late effects from the exposure to low doses of ionizing radiation are hardly or not at all observed in man mainly due to the low values of risk coefficients that preclude statistical analyses of data from populations that are exposed to doses less than 0.2 Gy. In order to arrive at an assessment of potential risk from radiation exposure in the low dose range, the microdosimetry approach is essential. In the low dose range, ionizing radiation generates particle tracks, mainly electrons, which are distributed rather heterogeneously within the exposed tissue. Taking the individual cell as the elemental unit of life, observations and calculations of cellular responses to being hit by energy depositions events from low LET type are analysed. It emerges that besides the probability of a hit cell to sustain a detrimental effect with the consequense of malignant transformation there are probabilities of various adaptive responses that equipp the hit cell with a benefit. On the one hand, an improvement of cellular radical detoxification was observed in mouse bone marrow cells; another adaptive response pertaining to improved DNA repair, was reported for human lymphocytes. The improved radical detoxification in mouse bone marrow cells lasts for a period of 5-10 hours and improved DNA repair in human lymphocytes was seen for some 60 hours following acute irradiation. It is speculated that improved radical detoxification and improved DNA repair may reduce the probability of spontaneous carcinogenesis. Thus it is proposed to weigh the probability of detriment for a hit cell within a multicellular system against the probability of benefit through adaptive responses in other hit cells in the same system per radiation exposure. In doing this, the net effect of low doses of low LET radiation in tissue with individual cells being hit by energy deposition events could be zero or even beneficial. (orig./MG)

  20. A high absorbance material for solar collectors' applications

    International Nuclear Information System (INIS)

    Oliva, A I; Maldonado, R D; Díaz, E A; Montalvo, A I

    2013-01-01

    In this work, we proposed a low cost material to be used as an excellent absorber for solar collectors, to increase its thermal efficiency by the high capacity to absorb solar radiation. The material, known as 'smoke black' (soot) can be obtained by the incomplete combustion of organic materials, such as the oxygen-acetylene, paraffin, or candles. A comparative analysis between the optical properties (reflectance, absorbance, and emissivity) measured on three covered copper surfaces (without paint, with a commercial matte black paint, and with smoke black) shows amazing optical results for the smoke black. Reflectance values of the smoke black applied over copper surfaces improves 56 times the values obtained from commercial black paints. High values of emissivity (E=0.9988) were measured on the surface covered with smoke black by spectrophotometry in the UV-VIS range, which represents about 7% of increment as compared with the value obtained for commercial black paints (E=0.938). The proposed high absorbance material can be easily applied on any kind of surfaces at low cost.

  1. Radiation absorbed doses in the event of balloon rupture (BR) during endovascular brachytherapy (EB) using 188Re-perrhenate

    International Nuclear Information System (INIS)

    Angelides, S.; Hetherington, E.; Karolis, C.; Walker, B.; Jackson, T.; Knittel, T.; Friend, C.; Pitney, M.; Jepson, N.; Milross, C.; Lonergan, D.

    2000-01-01

    Full text: endovascular brachytherapy (EB) using liquid or solid radiation sources, is an effective emerging therapy for coronary artery disease. Liquid sources provide uniform radiation dose to the vessel wall. However the radiation burden in the unlikely event of BR is not insignificant. The aims of this study were to determine i) absorbed dose for various 188 Re radiopharmaceuticals in the event of BR, and ii) effects of thyroid uptake blocking agent, Lugol's iodine (Ll) and/or bladder catheterisation (BC). Dose calculations were based on MIRDOSE 3.1 with dynamic bladder model and MIRD Dose Estimate Report No.8 for 99 Tc m -pertechnetate, which has similar biokinetic properties to 188 Re-perrhenate. Normal renal function and a bladder voiding interval of 4.8h (1 minute with catheter) were assumed. BR was simulated ex-vivo by puncturing a Solaris angioplasty balloon filled with normal saline at 4 atm. LI, MAG3 and DTPA substantially reduces the radiation dose following BR, particularly to the thyroid, and BC reduces the bladder wall dose. Only the contents of the balloon leaked; 0.4 ml of the total volume of 1.8ml. As binding of 188 Re to ligands is cumbersome, we opted to use LI. Twenty five patients with in-stent re-stenosis have been treated using 188 Re-perrhenate (8 GBq/ml), with no BR. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  2. Intercomparison of standards of absorbed dose between the USSR and the UK

    Science.gov (United States)

    Berlyand, V. A.; Bregadze, J. I.; Burns, J. E.; Dusautoy, A. R.; Sharpe, P. H. G.

    1991-05-01

    A comparison of national standards of absorbed dose was carried out between the All-Union Research Institute for Physical Technical and Radiotechnical Measurements (VNIIFTRI), USSR, and the National Physical Laboratotry (NPL), UK (United Kingdom). Absorbed dose to water for cobalt 60 gamma radiation was compared by means of Fricke dosimeters and ionization chambers in 1985 and 1986. The primary standards used to derive absorbed dose to water were cavity ionization chambers at NPL and a graphite calorimeter at VNIIFTRI. The ratio of absorbed dose to water, NPL to VNIIFTRI, using Fricke dosimeters was 1.008; using ionization chambers it was 1.007. This agreement is within the estimated uncertainties of the standards and measurement methods.

  3. Radiation energy collector

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Bei Tse; Rabl, A

    1977-02-10

    The invention deals with a concentrating solar collector. Collectors of this kind often have considerable natural convection losses which are due, among other facts, to the location of the energy absorber at the outlet with the heated surface of the absorber facing the inlet opening of the collector. According to the invention, the collector is designed in such manner that the absorber is located inside a space in such a way that the radiation emitted by the absorber is reflected back to the absorber with the aid of mirror surfaces. Various designs are described.

  4. Basic reactions induced by radiation

    International Nuclear Information System (INIS)

    Charlesby, A.

    1980-01-01

    This paper summarises some of the basic reactions resulting from exposure to high energy radiation. In the initial stages energy is absorbed, but not necessarily at random, giving radical and ion species which may then react to promote the final chemical change. However, it is possible to intervene at intermediate stages to modify or reduce the radiation effect. Under certain conditions enhanced reactions are also possible. Several expressions are given to calculate radiation yield in terms of energy absorbed. Some analogies between radiation-induced reactions in polymers, and those studied in radiobiology are outlined. (author)

  5. Peculiarities of absorbed dose forming in some wild animals in Chornobyl,y exclusion zone

    International Nuclear Information System (INIS)

    Gaychenko, V.A.; Krainiuk, O.Yu.

    2015-01-01

    Based on field researches conducted in the exclusion zone of the Chernobyl nuclear power plant in the years after the accident, identified the peculiarities of formation absorbed doses in animals of different taxonomic and ecological groups that live in conditions of radioactive contamination of ecosystems. Was shown importance of consideration of radiation features on wild animals according to their life cycle, conditions and ways of life. Was displayed data about the importance of different types of irradiation according to the period of stay the animals in the ground, in burrows and nests. Was reviewed the questions about value of external and internal radiation in absorbed dose of different types of wildlife. Was shown the results of the calculation of the absorbed dose of bird embryos from egg shell

  6. Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser

    Science.gov (United States)

    Williams, M. D.

    1984-01-01

    The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

  7. Estimativa do saldo de radiação em girassol como função da radiação solar global Estimation of net radiation in sunflower as a function of solar radiation

    Directory of Open Access Journals (Sweden)

    Arno B Heldwein

    2012-02-01

    Full Text Available Objetivou-se com este trabalho a obtenção de modelos para a estimativa do saldo de radiação (Q* a partir da radiação solar global incidente (Rg sobre dosseis de plantas de girassol. Os experimentos foram conduzidos na área experimental da Universidade Federal de Santa Maria, nos anos de 2007, 2008 e 2009. O Q* foi medido com saldos radiômetros instalados acima das plantas e a Rg em estações meteorológicas automáticas. Para fins de cálculo foram efetuadas as somas diárias de Q* e de Rg, obtendo-se a relação entre Q* e Rg para cada dia. Obtiveram-se, então, modelos com elevado coeficiente de determinação e baixo RQME no teste entre valores medidos e estimados de um banco de dados independente, indicando precisão na estimativa do saldo de radiação em dosseis de girassol, independendo da época de cultivo no ano. A função linear geral obtida com dados de diferentes épocas de cultivo foi: Q* = 0,5285 Rg (R² = 0,95, que no teste apresentou RQME = 1,04 MJ m-2 d-1. Conclui-se que o saldo de radiação (Q* pode ser estimado utilizando-se a radiação solar global medida em estações automáticas, com precisão suficiente para os diferentes fins na agrometeorologia do girassol.This study aimed to develop models for estimating the net radiation (Q * from the incident solar radiation (Rg on canopies of sunflower plants. The experiments were conducted at the Plant Science Department of the Federal University of Santa Maria in 2007, 2008 and 2009 years. Q* was measured by net radiometers above the plants and Rg by automatic weather stations. For purposes of calculation, daily sums of Q* and Rg were performed, obtaining the relationship between Q* and Rg for each day. Models with high coefficient of determination and low RQME were obtained in test between measured and estimated values from an independent database, indicating precision to estimate net radiation in sunflower canopies, regardless of cultivation time in year. The general

  8. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

    Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

    1996-01-01

    Biological dosimetry has an important role to play in assessing the cumulative radiation exposure of persons working with radiation and also in estimating the true dose received during accidents involving external and internal exposure. Various biodosimetric methods have been tried to estimate radiation dose for the above purposes. Biodosimetric methods include cytogenetic, immunological and mutational assays. Each technique has certain advantages and disadvantages. We present here a review of each technique, the actual method used for detection of dose, the sensitivity of detection and its use in long term studies. (author)

  9. NET test blanket design and remote maintenance

    International Nuclear Information System (INIS)

    Holloway, C.; Hubert, P.

    1991-01-01

    The NET machine has three horizontal ports reserved for testing tritium breeding blanket designs during the physics phase and possibly five during the technology phase. The design of the ports and test blankets are modular to accept a range of blanket options, provide radiation shielding and allow routine replacement. Radiation levels during replacement or maintenance require that all operations must be carried out remotely. The paper describes the problems overcome in providing a port design which includes attachment to the vacuum vessel with double vacuum seals, an integrated cooled first wall and support guides for the test blanket module. The method selected to remotely replace the test module whilst controlling the spread of contamination is also adressed. The paper concludes that the provisions of a test blanket facility based on the NET machine design is feasible. (orig.)

  10. Estimation of absorbed doses on the basis of cytogenetic methods

    International Nuclear Information System (INIS)

    Shevchenko, V.A.; Rubanovich, A.V.; Snigiryova, G.P.

    1998-01-01

    Long-term studies in the field of radiation cytogenetics have resulted in the discovery of relationship between induction of chromosome aberrations and the type of ionizing radiation, their intensity and dose. This has served as a basis of biological dosimetry as an area of application of the revealed relationship, and has been used in the practice to estimate absorbed doses in people exposed to emergency irradiation. The necessity of using the methods of biological dosimetry became most pressing in connection with the Chernobyl accident in 1986, as well as in connection with other radiation situations that occurred in nuclear industry of the former USSR. The materials presented in our works demonstrate the possibility of applying cytogenetic methods for assessing absorbed doses in populations of different regions exposed to radiation as a result of accidents at nuclear facilities (Chernobyl, the village Muslymovo on the Techa river, the Three Mile Island nuclear power station in the USA where an accident occurred in 1979). Fundamentally, new possibilities for retrospective dose assessment are provided by the FISH-method that permits the assessment of absorbed doses after several decades since the exposure occurred. In addition, the application of this method makes it possible to restore the dynamics of unstable chromosome aberrations (dicentrics and centric rings), which is important for further improvement of the method of biological dosimetry based on the analysis of unstable chromosome aberrations. The purpose of our presentation is a brief description of the cytogenetic methods used in biological dosimetry, consideration of statistical methods of data analysis and a description of concrete examples of their application. (J.P.N.)

  11. Ultrathin triple-band polarization-insensitive wide-angle compact metamaterial absorber

    International Nuclear Information System (INIS)

    Shang, Shuai; Yang, Shizhong; Tao, Lu; Yang, Lisheng; Cao, Hailin

    2016-01-01

    In this study, the design, realization, and characterization of an ultrathin triple-band polarization-insensitive wide-angle metamaterial absorber are reported. The metamaterial absorber comprises a periodic array of modified six-fold symmetric snowflake-shaped resonators with strip spiral line load, which is printed on a dielectric substrate backed by a metal ground plane. It is shown that the absorber exhibits three distinct near-unity absorption peaks, which are distributed across C, X, Ku bands, respectively. Owing to the six-fold symmetry, the absorber is insensitive to the polarization of the incident radiation. In addition, the absorber shows excellent absorption performance over wide oblique incident angles for both transverse electric and transverse magnetic polarizations. Simulated surface current and field distributions at the three absorption peaks are demonstrated to understand the absorption mechanism. Particularly, the absorption modes come from the fundamental and high-order dipole resonances. Furthermore, the experimental verification of the designed absorber is conducted, and the measured results are in reasonable agreement with the simulated ones. The proposed ultrathin (∼0.018λ 0 , λ 0 corresponding to the lowest peak absorption frequency) compact (0.168λ 0 ×0.168λ 0 corresponding to the area of a unit cell) absorber enables potential applications such as stealth technology, electromagnetic interference and spectrum identification.

  12. Modification of Sunlight Radiation through Colored Photo-Selective Nets Affects Anthocyanin Profile in Vaccinium spp. Berries.

    Directory of Open Access Journals (Sweden)

    Laura Zoratti

    Full Text Available In recent years, the interest on the effects of the specific wavelengths of the light spectrum on growth and metabolism of plants has been increasing markedly. The present study covers the effect of modified sunlight conditions on the accumulation of anthocyanin pigments in two Vaccinium species: the European wild bilberry (V. myrtillus L. and the cultivated highbush blueberry (V. corymbosum L..The two Vaccinium species were grown in the same test field in the Alps of Trentino (Northern Italy under modified light environment. The modification of sunlight radiation was carried out in field, through the use of colored photo-selective nets throughout the berry ripening during two consecutive growing seasons. The anthocyanin profile was then assessed in berries at ripeness.The results indicated that the light responses of the two Vaccinium species studied were different. Although both studied species are shade-adapted plants, 90% shading of sunlight radiation was beneficial only for bilberry plants, which accumulated the highest content of anthocyanins in both seasons. The same condition, instead, was not favorable for blueberries, whose maturation was delayed for at least two weeks, and anthocyanin accumulation was significantly decreased compared to berries grown under sunlight conditions. Moreover, the growing season had strong influence on the anthocyanin accumulation in both species, in relation to temperature flow and sunlight spectra composition during the berry ripening period.Our results suggest that the use of colored photo-selective nets may be a complementary agricultural practice for cultivation of Vaccinium species. However, further studies are needed to analyze the effect of the light spectra modifications to other nutritional properties, and to elucidate the molecular mechanisms behind the detected differences between the two relative Vaccinium species.

  13. Absorbed dose in fibrotic microenvironment models employing Monte Carlo simulation

    International Nuclear Information System (INIS)

    Zambrano Ramírez, O.D.; Rojas Calderón, E.L.; Azorín Vega, E.P.; Ferro Flores, G.; Martínez Caballero, E.

    2015-01-01

    The presence or absence of fibrosis and yet more, the multimeric and multivalent nature of the radiopharmaceutical have recently been reported to have an effect on the radiation absorbed dose in tumor microenvironment models. Fibroblast and myofibroblast cells produce the extracellular matrix by the secretion of proteins which provide structural and biochemical support to cells. The reactive and reparative mechanisms triggered during the inflammatory process causes the production and deposition of extracellular matrix proteins, the abnormal excessive growth of the connective tissue leads to fibrosis. In this work, microenvironment (either not fibrotic or fibrotic) models composed of seven spheres representing cancer cells of 10 μm in diameter each with a 5 μm diameter inner sphere (cell nucleus) were created in two distinct radiation transport codes (PENELOPE and MCNP). The purpose of creating these models was to determine the radiation absorbed dose in the nucleus of cancer cells, based on previously reported radiopharmaceutical retain (by HeLa cells) percentages of the 177 Lu-Tyr 3 -octreotate (monomeric) and 177 Lu-Tyr 3 -octreotate-AuNP (multimeric) radiopharmaceuticals. A comparison in the results between the PENELOPE and MCNP was done. We found a good agreement in the results of the codes. The percent difference between the increase percentages of the absorbed dose in the not fibrotic model with respect to the fibrotic model of the codes PENELOPE and MCNP was found to be under 1% for both radiopharmaceuticals. (authors)

  14. [Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

    Science.gov (United States)

    Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

    2011-06-01

    Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

  15. Effect of respiratory motion on internal radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB (Netherlands)

    2014-11-01

    Purpose: Estimation of the radiation dose to internal organs is essential for the assessment of radiation risks and benefits to patients undergoing diagnostic and therapeutic nuclear medicine procedures including PET. Respiratory motion induces notable internal organ displacement, which influences the absorbed dose for external exposure to radiation. However, to their knowledge, the effect of respiratory motion on internal radiation dosimetry has never been reported before. Methods: Thirteen computational models representing the adult male at different respiratory phases corresponding to the normal respiratory cycle were generated from the 4D dynamic XCAT phantom. Monte Carlo calculations were performed using the MCNP transport code to estimate the specific absorbed fractions (SAFs) of monoenergetic photons/electrons, the S-values of common positron-emitting radionuclides (C-11, N-13, O-15, F-18, Cu-64, Ga-68, Rb-82, Y-86, and I-124), and the absorbed dose of {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) in 28 target regions for both the static (average of dynamic frames) and dynamic phantoms. Results: The self-absorbed dose for most organs/tissues is only slightly influenced by respiratory motion. However, for the lung, the self-absorbed SAF is about 11.5% higher at the peak exhale phase than the peak inhale phase for photon energies above 50 keV. The cross-absorbed dose is obviously affected by respiratory motion for many combinations of source-target pairs. The cross-absorbed S-values for the heart contents irradiating the lung are about 7.5% higher in the peak exhale phase than the peak inhale phase for different positron-emitting radionuclides. For {sup 18}F-FDG, organ absorbed doses are less influenced by respiratory motion. Conclusions: Respiration-induced volume variations of the lungs and the repositioning of internal organs affect the self-absorbed dose of the lungs and cross-absorbed dose between organs in internal radiation dosimetry. The dynamic

  16. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    Directory of Open Access Journals (Sweden)

    Ernesto Amato

    2014-03-01

    Full Text Available We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'generalized radius', calculated as 3V/S, where V is the ellipsoid volume and S its surface. Radiation-specific parametric functions were obtained in order to calculate the absorbed fraction of a given radiation in a generic ellipsoidal volume. The dose from a generic radionuclide can be calculated through a process of summation and integration over the whole radionuclide emission spectrum, profitably implemented in an electronic spreadsheet. We compared the results of our analytical calculation approach with those obtained from the OLINDA/EXM computer software, finding a good agreement in a wide range of sphere radii, for the high-energy pure beta emitter 90Y, the commonly employed beta-gamma emitter 131I, and the pure alpha emitter 213Po. The generality of our approach makes it useful an easy to implement in clinical dosimetry calculations as well as in radiation safety estimations when doses from internal radionuclide uptake are to be taken into account.

  17. Gyroscopic power take-off wave energy point absorber in irregular sea states

    DEFF Research Database (Denmark)

    Zhang, Zili; Chen, Bei; Nielsen, Søren R.K.

    2017-01-01

    Highlights •A GyroPTO wave energy point absorber with magnetic coupling mechanism is proposed. •A 4DOF nonlinear model of the GyroPTO absorber has been derived. •Rational approximations are performed on the radiation damping moments. •Synchronization of the device is more easily maintained...... in narrow-banded sea waves. •The generator gain and the magnetic coupling constant influence the performance of the device....

  18. Shielding calculations for NET

    International Nuclear Information System (INIS)

    Verschuur, K.A.; Hogenbirk, A.

    1991-05-01

    In the European Fusion Technology Programme there is only a small activity on research and development for fusion neutronics. Never-the-less, looking further than blanket design now, as ECN is getting involved in design of radiation shields for the coils and biological shields, it becomes apparent that fusion neutronics as a whole still needs substantial development. Existing exact codes for calculation of complex geometries like MCNP and DORT/TORT are put over the limits of their numerical capabilities, whilst approximate codes for complex geometries like FURNACE and MERCURE4 are put over the limits of their modelling capabilities. The main objective of this study is just to find out how far we can get with existing codes in obtaining reliable values for the radiation levels inside and outside the cryostat/shield during operation and after shut-down. Starting with a 1D torus model for preliminary parametric studies, more dimensional approximation of the torus or parts of it including the main heterogeneities should follow. Regular contacts with the NET-Team are kept, to be aware of main changes in NET design that might affect our calculation models. Work on the contract started 1 July 1990. The technical description of the contract is given. (author). 14 refs.; 4 figs.; 1 tab

  19. Absorbing coatings for high power millimeter-wave devices and matched loads

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Bruschi, A.; Cirant, S. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Muzzini, V. [Istituto di Biologia Agro-ambientale e Forestale, Consiglio Nazionale delle Ricerche, Area di Ricerca di Roma 1, Monterotondo, Rome (Italy); Simonetto, A.; Spinicchia, N. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Angella, G. [Istituto per l’Energetica e le Interfasi, Consiglio Nazionale delle Ricerche, Milano (Italy); Dell’Era, F. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Gantenbein, G.; Leonhardt, W. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany); Nardone, A. [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA/CNR Association, Milano (Italy); Samartsev, A.; Schmid, M. [Institut für Hochleistungsimpuls-und Mikrowellentechnik, Karlsruhe Institute of Technology, Association EURATOM-KIT, Karlsruhe (Germany)

    2013-10-15

    Highlights: ► An overview of the activity at IFP-CNR concerning the absorbing coatings is presented. ► The application of the absorbing ceramics to the IFP-CNR matched loads is described. ► B{sub 4}C is presented as a promising material for power absorption in the EC frequency range. ► The most important high power validation tests performed on coatings are described. ► Some results from simulations of the absorption capability of a double layer coating are shown. -- Abstract: In the electron cyclotron frequency range the handling of high power is critical. In some cases an unpredictable amount of stray radiation can reach some components or accumulate in localized regions, with risk of damages caused by thermal overloads, and any uncontrolled reflection represents a danger for the sources. A possibility to mitigate the problem consists in covering some regions exposed to radiation with absorbers. Enhanced absorption of stray radiation lowers requirements on active protection systems in microwave diagnostics. The released heat can be extracted by dedicated cooling systems. The chromium oxide (Cr{sub 2}O{sub 3}), largely tested at IFP-CNR, has been routinely used as internal coating for matched loads. The performances of a variable thickness coating has been tested at high power at Karlsruhe Institute of Technology (KIT), with a 140 GHz gyrotron of the W7-X ECRH system and an averaged power density absorbed at the coating surface higher than 1 MW/m{sup 2} for 3 min. Also boron carbide (B{sub 4}C) has been tested at low power and patented as a millimeter-wave absorber. In the paper, the results of some tests performed on these coatings are given, together with some simulations of the absorption capability based on low power measurements on samples. Finally, some calculations are presented for a coating obtained combining together Cr{sub 2}O{sub 3} and B{sub 4}C.

  20. Experimental demonstration of ultrasensitive sensing with terahertz metamaterial absorbers: A comparison with the metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Longqing; Singh, Ranjan, E-mail: ranjans@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Tan, Siyu [School of Electrical Engineering and Computer Science, Oklahoma State University, Stillwater, Oklahoma 87074 (United States); Key Lab of All Optical Network and Advanced Telecommunication Network of EMC, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Yahiaoui, Riad [XLIM, Limoges University, CNRS, UMR 7252, 7 rue Jules Vallès, F-19100 Brive (France); Yan, Fengping [Key Lab of All Optical Network and Advanced Telecommunication Network of EMC, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Weili [School of Electrical Engineering and Computer Science, Oklahoma State University, Stillwater, Oklahoma 87074 (United States)

    2015-01-19

    Planar metasurfaces and plasmonic resonators have shown great promise for sensing applications across the electromagnetic domain ranging from the microwaves to the optical frequencies. However, these sensors suffer from lower figure of merit and sensitivity due to the radiative and the non-radiative loss channels in the plasmonic metamaterial systems. We demonstrate a metamaterial absorber based ultrasensitive sensing scheme at the terahertz frequencies with significantly enhanced sensitivity and an order of magnitude higher figure of merit compared to planar metasurfaces. Magnetic and electric resonant field enhancement in the impedance matched absorber cavity enables stronger interaction with the dielectric analyte. This finding opens up opportunities for perfect metamaterial absorbers to be applied as efficient sensors in the finger print region of the electromagnetic spectrum with several organic, explosive, and bio-molecules that have unique spectral signature at the terahertz frequencies.

  1. Conversion of ionization measurements to radiation absorbed dose in non-water density material

    International Nuclear Information System (INIS)

    El-Khatib, E.; Connors, S.

    1992-01-01

    In bone-equivalent materials two different calculations of absorbed dose are possible: the absorbed dose to soft tissue plastic (polystyrene) within bone-equivalent material and the dose to the bone-equivalent material itself. Both can be calculated from ionization measurements in phantoms. These two calculations result in significantly different doses in a heterogeneous phantom composed of polystyrene and aluminium (a bone substitute). The dose to a thin slab of polystyrene in aluminium is much higher than the dose to the aluminium itself at the same depth in the aluminium. Monte Carlo calculations confirm that the calculation of dose to polystyrene in aluminium can be accurately carried out using existing dosimetry protocols. However, the conversion of ionization measurements to absorbed dose to high atomic number materials cannot be accurately carried out with existing protocols and appropriate conversion factors need to be determined. (author)

  2. Radiation absorbed dose to the human fetal thyroid

    International Nuclear Information System (INIS)

    Watson, E.E.

    1992-01-01

    The embryo/fetus is recognized to be particularly susceptible to damage from exposure to radiation. Many advisory groups have studied available information concerning radiation doses and radiation effects with the goal of reducing the risk to the embryo/fetus. Of particular interest are radioactive isotopes of iodine. Radioiodine taken into the body of a pregnant woman presents a possible hazard for the embryo/fetus. The fetal thyroid begins to concentrate iodine at about 13 weeks after conception and continues to do so throughout gestation. At term, the organic iodine concentration in the fetal blood is about 75% of that in the mother's blood. This paper presents a review the models that have been proposed for the calculation of the dose to the fetal thyroid from radioisotopes of iodine taken into the body of the pregnant woman as sodium iodide. A somewhat different model has been proposed, and estimates of the radiation dose to the fetal thyroid calculated from this model are given for each month of pregnancy from 123 I , 124 I , 125 I , and 131 I

  3. Investigations on laser transmission welding of absorber-free thermoplastics

    Science.gov (United States)

    Mamuschkin, Viktor; Olowinsky, Alexander; Britten, Simon W.; Engelmann, Christoph

    2014-03-01

    Within the plastic industry laser transmission welding ranks among the most important joining techniques and opens up new application areas continuously. So far, a big disadvantage of the process was the fact that the joining partners need different optical properties. Since thermoplastics are transparent for the radiation of conventional beam sources (800- 1100 nm) the absorbance of one of the joining partners has to be enhanced by adding an infrared absorber (IR-absorber). Until recently, welding of absorber-free parts has not been possible. New diode lasers provide a broad variety of wavelengths which allows exploiting intrinsic absorption bands of thermoplastics. The use of a proper wavelength in combination with special optics enables laser welding of two optically identical polymer parts without absorbers which can be utilized in a large number of applications primarily in the medical and food industry, where the use of absorbers usually entails costly and time-consuming authorization processes. In this paper some aspects of the process are considered as the influence of the focal position, which is crucial when both joining partners have equal optical properties. After a theoretical consideration, an evaluation is carried out based on welding trials with polycarbonate (PC). Further aspects such as gap bridging capability and the influence of thickness of the upper joining partner are investigated as well.

  4. Problems of photo-radiative action

    International Nuclear Information System (INIS)

    Milinchuk, V.K.

    1985-01-01

    The most interesting photo-radiation effects observed in the last few years are discussed, in particular, considerable reduction ip material radiation resistance under the combined effect of ionizing and visible radiation. Intermediate active particles are shown to absorb the light according to the mechanism of ''direct'' absorption and as a result of photo-sensibilization reactions as well. Channels of absorbed light energy dissipation depend on the nature and structure of the intermediate active particles, temperature, light radiation frequency and other parameters. Problems are considered which solution promotes further development of photo-radiation chemistry and that are important for such branches of modern physical chemistry as kinetics and mechanism of elementary processes in organic solids, radiation resistance and ageing of organic polymers

  5. Relations between radiation fluxes of a greenhouse in semi-arid conditions

    International Nuclear Information System (INIS)

    Al-Riahi, M.; Al-Karaghouli, A.; Hasson, A.M.; Al-Kayssi, A.W.

    1989-01-01

    Measurements of global radiation, reflected radiation and net total radiation inside and outside the greenhouse were conducted in Fudhiliyah Agrometeorological Research Station during the period from 1 January to 30 April, 1987. From these measurements, several relationships were established. Linear regressions of hourly values of global radiation inside the greenhouse on hourly global radiation outside the greenhouse were fitted for each month of the recording period. The degree of fit was generally good (r > 0.95). Net short-wave radiation inside the greenhouse showed strong dependence on the global inside radiation (r = 0.998), also the net total radiation and global radiation inside the greenhouse correlate very strongly. From the above-mentioned relationships, it was found that the global, net short-wave and net total radiation could be successfully predicted when only global outside radiation is available. Using the linear regression equations correlating the above radiation parameters, albedo and heating coefficient were derived. Albedo showed strong dependence on solar altitude angle and period of day (forenoon and afternoon). Heating coefficients were consistently positive and their values varied between 0.10 and 0.393. Monthly average values of mean hourly night-time net long-wave radiation inside the greenhouse were −31, −32, −38 and −42 W m −2 for the months of January, February, March and April, respectively

  6. Performance analysis of solar air heater with jet impingement on corrugated absorber plate

    Directory of Open Access Journals (Sweden)

    Alsanossi M. Aboghrara

    2017-09-01

    Full Text Available This paper deals with the experimental investigation outlet temperature and efficiency, of Solar Air heater (SAH. The experimental test set up designed and fabricated to study the effect of jet impingement on the corrugated absorber plate, through circular jets in a duct flow of solar air heater, and compared with conventional solar air heater on flat plat absorber. Under effect of mass flow rate (ṁ of air and solar radiation on outlet air temperature, and efficiency, are analyzed. Results show the flow jet impingement on corrugated plat absorber is a strong function of heat transfer enhancement. The present investigation concludes that the mass flow rate of air substantially influences the heat transfer on solar air heaters. And the thermal efficiency of proposed design duct is observed almost 14% more as compare to the smooth duct. At solar radiation 500–1000 (W/M2, 308 K ambient temperature and 0.01–0.03 (Kg/S mass flow rate

  7. Neutron absorbing article and method for manufacture of such article

    International Nuclear Information System (INIS)

    Hortman, M.T.; Mcmurtry, C.H.; Naum, R.G.; Owens, D.P.

    1980-01-01

    A neutron absorbing article, preferably in long, thin, flat form , suitable for but not necessarily limited to use in storage racks for spent nuclear fuel at locations between volumes of such stored fuel, to absorb neutrons from said spent fuel and prevent uncontrolled nuclear reaction of the spent fuel material, is composed of finely divided boron carbide particles and a solid, irreversibly cured phenolic polymer, forming a continuous matrix about the boron carbide particles, in such proportions that at least 6% of b10 from the boron carbide content is present therein. The described articles withstand thermal cycling from repeated spent fuel insertions and removals, withstand radiation from said spent nuclear fuel over long periods of time without losing desirable neutron absorbing and physical properties, are sufficiently chemically inert to water so as to retain neutron absorbing properties if brought into contact with it, are not galvanically corrodible and are sufficiently flexible so as to withstand operational basis earthquake and safe shutdown earthquake seismic events, without loss of neutron absorbing capability and other desirable properties, when installed in storage racks for spent nuclear fuel. The disclosure also relates to a plurality of such neutron absorbing articles in a storage rack for spent nuclear fuel and to a method for the manufacture of the articles

  8. Determination of absorbed dose to the lens of eye from external sources

    International Nuclear Information System (INIS)

    Chen Lishu

    1993-01-01

    The methods of determining absorbed dose distributions in human eyeball by means of the experiments and available theories have been reported. A water phantom was built up. The distributions of beta dose were measured by an extrapolation ionization chamber at some depths corresponding to components of human eyeball such as cornea, sclera, anterior chamber and the lens of eye. The ratios among superficial absorbed dose (at 0.07 mm) and average absorbed doses at the depths 1,2,3 mm are obtained. They can be used for confining the deterministic effects of superficial tissues and organs such as the lens of eye for weakly penetrating radiations

  9. Shock absorber

    International Nuclear Information System (INIS)

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  10. Simulation of bulk aerosol direct radiative effects and its climatic feedbacks in South Africa using RegCM4

    Science.gov (United States)

    Tesfaye, M.; Botai, J.; Sivakumar, V.; Mengistu Tsidu, G.; Rautenbach, C. J. deW.; Moja, Shadung J.

    2016-05-01

    In this study, 12 year runs of the Regional Climate Model (RegCM4) have been used to analyze the bulk aerosol radiative effects and its climatic feedbacks in South Africa. Due to the geographical locations where the aerosol potential source regions are situated and the regional dynamics, the South African aerosol spatial-distribution has a unique feature. Across the west and southwest areas, desert dust particles are dominant. However, sulfate and carbonaceous aerosols are primarily distributed over the east and northern regions of the country. Analysis of the Radiative Effects (RE) shows that in South Africa the bulk aerosols play a role in reducing the net radiation absorbed by the surface via enhancing the net radiative heating in the atmosphere. Hence, across all seasons, the bulk aerosol-radiation-climate interaction induced statistically significant positive feedback on the net atmospheric heating rate. Over the western and central parts of South Africa, the overall radiative feedbacks of bulk aerosol predominantly induces statistically significant Cloud Cover (CC) enhancements. Whereas, over the east and southeast coastal areas, it induces minimum reductions in CC. The CC enhancement and RE of aerosols jointly induce radiative cooling at the surface which in turn results in the reduction of Surface Temperature (ST: up to -1 K) and Surface Sensible Heat Flux (SSHF: up to -24 W/m2). The ST and SSHF decreases cause a weakening of the convectively driven turbulences and surface buoyancy fluxes which lead to the reduction of the boundary layer height, surface pressure enhancement and dynamical changes. Throughout the year, the maximum values of direct and semi-direct effects of bulk aerosol were found in areas of South Africa which are dominated by desert dust particles. This signals the need for a strategic regional plan on how to reduce the dust production and monitoring of the dust dispersion as well as it initiate the need of further research on different

  11. Primordial radionuclides in soil and their contributions to absorbed dose rate in air

    International Nuclear Information System (INIS)

    Moriones, C.R.; Duran, E.B.; Cruz, F.M. de la

    1989-01-01

    The predominant primordial radionuclides in soil which give rise to terrestrial radiation (external irradiation) were analyzed by gamma spectrometry. 40 K has the highest average activity mass concentration, i.e. 212 Bq kg -1 . 238 U and 232 Th concentrations are much lower and are only 14 and 16 Bq kg -1 respectively. Based on conversion factors given in the UNSCEAR Report (1988), the absorbed dose rates in air at one meter above the ground surface per unit activity mass concentration of primordial radionuclides were calculated. The average per caput absorbed dose rate in air received by Filipinos due to terrestrial radiation is 23 nGy h -1 . The relative contribution of 232 Th series to the total absorbed dose rate is highest, followed closely by 40 K. The contribution of 238 U series is only about one-half that of the 232 Th series. Based on the results obtained, the terrestrial component of the average per caput exposure dose rate due to natural radiation sources is 2.64 μR h -1 or roughly 3 μR h -1 . This leads to an annual average effective dose equivalent to 202 μSv. (Author). 5 annexes; 4 figs.; 3 tabs.; 6 refs

  12. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    OpenAIRE

    Amato, Ernesto; Italiano, Antonio; Baldari, Sergio

    2014-01-01

    We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'general...

  13. Evaluation of the absorbed dose in odontological computerized tomography

    International Nuclear Information System (INIS)

    Legnani, Adriano; Schelin, Hugo R.; Rocha, Anna Silvia P.S. da; Khoury, Helen J.

    2011-01-01

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  14. Sudden Exposure to Solar UV-B Radiation Reduces Net CO2 Uptake and Photosystem I Efficiency in Shade-Acclimated Tropical Tree Seedlings1

    Science.gov (United States)

    Krause, G. Heinrich; Grube, Esther; Virgo, Aurelio; Winter, Klaus

    2003-01-01

    Tree seedlings developing in the understory of the tropical forest have to endure short periods of high-light stress when tree-fall gaps are formed, and direct solar radiation, including substantial UV light, reaches the leaves. In experiments simulating the opening of a tree-fall gap, the response of photosynthesis in leaves of shade-acclimated seedlings (Anacardium excelsum, Virola surinamensis, and Calophyllum longifolium) to exposure to direct sunlight (for 20–50 min) was investigated in Panama (9°N). To assess the effects of solar UV-B radiation (280–320 nm), the sunlight was filtered through plastic films that selectively absorbed UV-B or transmitted the complete spectrum. The results document a strong inhibition of CO2 assimilation by sun exposure. Light-limited and light-saturated rates of photosynthetic CO2 uptake by the leaves were affected, which apparently occurred independently of a simultaneous inhibition of potential photosystem (PS) II efficiency. The ambient UV-B light substantially contributed to these effects. The photochemical capacity of PSI, measured as absorbance change at 810 nm in saturating far-red light, was not significantly affected by sun exposure of the seedlings. However, a decrease in the efficiency of P700 photooxidation by far-red light was observed, which was strongly promoted by solar UV-B radiation. The decrease in PSI efficiency may result from enhanced charge recombination in the reaction center, which might represent an incipient inactivation of PSI, but contributes to thermal dissipation of excessive light energy and thereby to photoprotection. PMID:12586898

  15. Usefulness of radiation treatment planning allpied respiration factor for streotatic body radiation therapy in the lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Pil; Kim, Tae Hyung; So, Woon Young; Back, Geum Mun [Dept. of Medical Health Science, Graduate School, Kangwon National University, Chuncheon (Korea, Republic of)

    2016-12-15

    We are evaluated the usefulness of radiation treatment planning applied respiration factor for stereotactic body radiation therapy in the lung cancer. Four dimensional computed tomography images were obtained in 10 patients with lung cancer. The radiation treatment plans were established total lung volume according to respiration images (new method) and conventional method. We was analyzed in the lung volume, radiation absorbed dose of lung and main organs (ribs, tracheobronchus, esophagus, spinal cord) around the tumor, respectively. We were confirmed that lung volume and radiation absorbed dose of lung and main organs around the tumor deference according to applied respiration. In conclusion, radiation treatment planning applied respiration factor seems to be useful for stereotactic body radiation therapy in the lung cancer.

  16. Shock absorbing structure

    International Nuclear Information System (INIS)

    Kojima, Naoki; Matsushita, Kazuo.

    1992-01-01

    Small pieces of shock absorbers are filled in a space of a shock absorbing vessel which is divided into a plurality of sections by partitioning members. These sections function to prevent excess deformation or replacement of the fillers upon occurrence of falling accident. Since the shock absorbing small pieces in the shock absorbing vessel are filled irregularly, shock absorbing characteristics such as compression strength is not varied depending on the direction, but they exhibit excellent shock absorbing performance. They surely absorb shocks exerted on a transportation vessel upon falling or the like. If existing artificial fillers such as pole rings made of metal or ceramic and cut pieces such as alumium extrusion molding products are used as the shock absorbing pieces, they have excellent fire-proofness and cold resistance since the small pieces are inflammable and do not contain water. (T.M.)

  17. Proposal of a weight factor for alpha radiation aiming biota radioprotection

    International Nuclear Information System (INIS)

    Pereira, Wagner de S.; Py Junior, Delcy de A.; Kelecom, Alphonse; Goncalves, Simone

    2009-01-01

    Several proposals based on the environmental radioprotection of calculating the absorbed dose in biota have been suggested. The absorbed dose expresses the deposition of energy per mass unit. The differences in biological effects of the absorbed dose can be quantified by applying a correction factor to the absorbed dose. The correction factor for radiation is easier to establish, because radiations exist in smaller number (alpha, beta, neutrons and photons) and can be set for groups of organisms. This work aims to propose a correction factor for radiation, in order to adequate the concept of absorbed dose currently used to the concept of equivalent dose. A survey of the literature on correction factors proposed for alpha radiation was carried out and, when possible, the biological endpoint was identified, as well as the radionuclide and the biological target. A variation of the weight factor for alpha radiation from 1 to 377 was observed and a number of biological endpoints, biological target and alpha emitter radionuclide were identified. Finally we propose a weight value for alpha radiation of 40, and we propose also the name of correction factor for radiation alpha as being ecological radiation weighting factor (WRE) the name 'equivalent dose for flora and fauna' (HTFF) to name of the new dose. (author)

  18. Calculation of absorbed dose in water by chemical Fricke dosimetry

    International Nuclear Information System (INIS)

    Rodrigues, Adenilson Paiva; Meireles, Ramiro Conceicao

    2016-01-01

    This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)

  19. Absorbed dose optimization in the microplanar beam radiotherapy

    International Nuclear Information System (INIS)

    Company, F.Z.; Jaric, J.; Allen, B.J.

    1996-01-01

    Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate, small divergence and sharply defined microbeam margins permit investigation of the application of an array of closely spaced, parallel or converging microbeams for radiotherapy. The proposed technique takes advantage of the repair mechanism hypothesis of capillary endothelial cells between alternate microbeam zones, which regenerates the lethally irradiated capillaries. Unlike a pencil beam, more accurate dose calculation, beam width and spacing are essential to minimise radiation damage to normal tissue cells outside the target. The absorbed dose between microbeam zones should be kept below the threshold for irreversible radiation damage. Thus the peak-to-valley ratio for the dose distribution should be optimized. The absorbed dose profile depends on the energy of the incident beam and the composition and density of the medium. Using Monte Carlo computations, the radial absorbed dose of single 24 x 24 μm 2 cross-section X-ray beams of different energies in a tissue/lung/tissue phantom was investigated. The results indicated that at 100 keV, closely spaced square cross-sectional microbeams can be applied to the lung. A bundle of parallel 24 μm-wide planar microbeams spaced at 200 μm intervals provides much more irradiation coverage of tissue than is provided by a bundle of parallel, square cross-sectional microbeam, although the former is associated with much smaller Peak (maximum absorbed dose on the beam axis) -to-Valley ( minimum interbeam absorbed dose ) ratios than the latter. In this study the lateral and depth dose of single and multiple microplanar beams with beam dimensions of width 24 μm and 48 μm and height 2-20 cm with energy of 100 keV in a tissue/lung/tissue phantom are investigated. The EGS4 Monte Carlo code is used to calculate dose profiles at different depths and bundles of beams (2 x 2 cm 2 to 20 x 20 cm 2 square cross section) with a 150 μm 200 μm and

  20. International comparison of calibration standards for exposure and absorbed dose

    International Nuclear Information System (INIS)

    Horakova, I.; Wagner, R.

    1990-01-01

    A comparison was performed of the primary calibration standards for 60 Co gamma radiation dose from Czechoslovakia (UDZ CSAV, Prague), Austria (OEFZS/BEV Seibersdorf) and Hungary (OMH Budapest) using ND 1005 (absolute measurement) and V-415 (by means of N x ) graphite ionization chambers. BEV achieved agreement better than 0.1%, OMH 0.35%. Good agreement was also achieved for the values of exposure obtained in absolute values and those obtained via N x , this for the ND 1005/8105 chamber. The first ever international comparison involving Czechoslovakia was also performed of the unit of absorbed gamma radiation in a water and/or graphite phantom. The participants included Czechoslovakia (UDZ CSAV Prague), the USSR (VNIIFTRI Moscow) and Austria (OEFZS/BEV Seibersdorf). In all measurements, the agreement was better than 1%, which, in view of the differences in methodologies (VNIIFTRI, BEV: calorimetry, UDZ, UVVVR: ionometry) and the overall inaccuracies in determining the absorbed dose values, is a good result. (author)

  1. Chapter 1: A little of Radiation Physics and radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2018-04-01

    The chapter 1 presents the subjects: 1) quantities and units of radiation physics which includes: the electron volt (eV); Exposure (X); Absorbed dose (D); Dose equivalent (H); Activity (A); Half-life; Radioactive decay; 2) Radiation protection which includes: irradiation and radioactive contamination; irradiation; contamination; background radiation; dose limits for individual occupationally exposed (IOE) and for the general public.

  2. Time improvement of photoelectric effect calculation for absorbed dose estimation

    International Nuclear Information System (INIS)

    Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E

    2007-01-01

    Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant

  3. Environment and health: 3. Ozone depletion and ultraviolet radiation

    International Nuclear Information System (INIS)

    De Gruijl, F.R.; Van der Leun, J.C.

    2000-01-01

    Ultraviolet radiation from the sun is responsible for a variety of familiar photochemical reactions, including photochemical smog, bleaching of paints and decay of plastics. Conjugated bonds in organic molecules such as proteins and DNA absorb the UV radiation, which can damage these molecules. By a fortunate evolutionary event, the oxygen produced by photosynthesis forms a filter in the outer reaches of our atmosphere that absorbs the most energetic and harmful UV radiation, with wavelengths below 240 nm (in the UVC band [wavelength 100-280 nm]). In the process, the oxygen molecules split up and recombine to form ozone (Fig. 1). This ratified ozone layer (spread out between 10 and 50 Ion in the stratosphere but only 3 mm thick were it compressed at ground level) in turn efficiently absorbs UV radiation of higher wavelengths (tip to about 310 nm). A part of the UV radiation in the UVB band (wavelength 280-315 nm) still reaches ground level and is absorbed in sufficient amounts to have deleterious effects on cells. The less energetic radiation in the UVA band (wavelength 315-400 nm, bordering the visible band [wavelength 400-800 nm]) is not absorbed by ozone and reaches ground level without much attenuation through a clear atmosphere (i.e., no clouds, no air pollution). Although not completely innocuous, the UVA radiation in sunlight is much less photochemically active and therefore generally less harmful than UVB radiation. Life on earth has adapted itself to the UV stress, particularly UVB stress, fbr example by forming protective UV-absorbing surface layers, by repairing cell damage or by replacing damaged cells entirely. Human skin shows all of these adaptive features. Our eyes are less well adapted, but dicy, are shielded by the brows and by squinting. (author)

  4. What is cosmic radiation?

    International Nuclear Information System (INIS)

    2004-01-01

    The earth was indeed receiving ionizing radiations from the heavens. This cosmic radiation consists of particles travelling near the speed of light. It consists of two components, the first of which is permanent and of galactic origin, while the other is more sporadic, depending on the sun's activities. Natural land-based sources expose each of us to an average total dose of 2.4 mSv per year (source UNSCEAR). In addition, the human activities using ionizing radiation contribute to an average annual exposure of 1.4 mSv, originating primarily with medical activities ( radiodiagnostic and radiation therapy). Members of flights crew are subject to exposure. The total dose of cosmic radiation received is is directly proportional with the duration of exposure, and thus with the duration of the flight. Measurement taken on board aircraft during the 1990's showed that flight personnel (on long haul flights) receive an average dose of approximately the same magnitude as the one due to exposure to natural radioactivity in France. The damage caused by ionizing radiation depends on the quantity of energy released by radiation into the cells of each organ or tissue of the human body(exposure dose). For a given quantity of absorbed energy (dose expressed in Gray), the damage will vary according to the nature of the radiation and the affected organ. These effects are of two types: acute effects and deferred effects. Two measurements are essential for radiation protection: the measurements of the dose of radiation absorbed by the body and the assessment of the risk associated with the absorbed dose. Two units were thus created: the gray and the sievert. (N.C.)

  5. Exposure limits: the underestimation of absorbed cell phone radiation, especially in children.

    Science.gov (United States)

    Gandhi, Om P; Morgan, L Lloyd; de Salles, Alvaro Augusto; Han, Yueh-Ying; Herberman, Ronald B; Davis, Devra Lee

    2012-03-01

    The existing cell phone certification process uses a plastic model of the head called the Specific Anthropomorphic Mannequin (SAM), representing the top 10% of U.S. military recruits in 1989 and greatly underestimating the Specific Absorption Rate (SAR) for typical mobile phone users, especially children. A superior computer simulation certification process has been approved by the Federal Communications Commission (FCC) but is not employed to certify cell phones. In the United States, the FCC determines maximum allowed exposures. Many countries, especially European Union members, use the "guidelines" of International Commission on Non-Ionizing Radiation Protection (ICNIRP), a non governmental agency. Radiofrequency (RF) exposure to a head smaller than SAM will absorb a relatively higher SAR. Also, SAM uses a fluid having the average electrical properties of the head that cannot indicate differential absorption of specific brain tissue, nor absorption in children or smaller adults. The SAR for a 10-year old is up to 153% higher than the SAR for the SAM model. When electrical properties are considered, a child's head's absorption can be over two times greater, and absorption of the skull's bone marrow can be ten times greater than adults. Therefore, a new certification process is needed that incorporates different modes of use, head sizes, and tissue properties. Anatomically based models should be employed in revising safety standards for these ubiquitous modern devices and standards should be set by accountable, independent groups.

  6. Rational system of radiation dosimetry

    International Nuclear Information System (INIS)

    Katoh, K.; Tada, J.

    1996-01-01

    Radiation doses are the most important subject to the sciences relating to the effects of ionizing radiation on matter. Since any science at all must stand on the quantitative description of causality, uses of physical quantities as the measures are indispensable. The current system of radiation dosimetry is built on the fundamental dose of the absorbed dose, which is defined as the 'energy imparted' density, and for practical convenience various weighted absorbed doses are introduced as subsidiary. However, it has been pointed out that these quantities lack adequacy inherently as a measure of causes, in addition to the insufficiency of the specification of the concept. Firstly, separation of the quantities of radiation field and of the dose is not possible, since both quantities are deeply related to the same microscopic constituents, i.e., electrons. Secondly, the value of the absorbed dose cannot be fixed at the moment of irradiation. Since the absorbed dose is a quantity of interaction product of radiation and matter, the values of the dose cannot be fixed instantaneously. Thirdly, it is not easy to envision the physical entity of the quantity from the definition. The form of existence of the 'imparted' energy is not clear in the current definition. These defects can not be removed as long as an interaction product is adopted as the dose quantity. In this paper, the authors present a prescription to solve these problems. (author)

  7. Ultraviolet radiation

    International Nuclear Information System (INIS)

    Hawk, J.

    1986-01-01

    Ultraviolet radiation (UVR) from the sun or artificial sources is reflected or transmitted at the surface of the skin, about 5% of normally incident rays being directly reflected. The transmitted fraction is scattered, photochemically absorbed or dissipated as heat within the skin, or passes from it to contribute to the variable total amount of reflected and transmitted radiation. The UVR absorbers in skin are not definitely known, but DNA is a definite target and probably lipoprotein membranes, RNA, proteins, mucopolysaccharides, elastin and collagen. Photochemical or free radical damage to absorber or nearby organelles leads to pharmacological, ultrastructural, histological and clinical changes. Most frequent DNA damage is pyrimidine dimer formation, apparently inhibiting cell function and replication. This is largely enzymatically repaired in man in the dark by excision repair, post-replication repair and possible other enzymatic mechanisms, and at least in some organisms by light-induced photoreactivation repair. UVR exposure causes well recognized acute and chronic clinical syndromes in man. These are discussed in this paper

  8. Effects of enhanced ultraviolet-B radiation, water deficit, and their combination on UV-absorbing compounds and osmotic adjustment substances in two different moss species.

    Science.gov (United States)

    Hui, Rong; Zhao, Ruiming; Song, Guang; Li, Yixuan; Zhao, Yang; Wang, Yanli

    2018-05-01

    A simulation experiment was conducted to explore the influence of enhanced ultraviolet-B (UV-B) radiation, water deficit, and their combination on UV-absorbing compounds and osmotic adjustment substances of mosses Bryum argenteum and Didymodon vinealis isolated from biological soil crusts (BSCs) growing in a revegetated area of the Tengger Desert, China. Four levels of UV-B radiation and two gradients of water regime were employed. Compared with their controls, amounts of total flavonoids, chlorophyll, carotenoids, soluble sugars, and soluble proteins significantly decreased (p argenteum, D. vinealis was more resistant to enhanced UV-B and water deficit singly and in combination. These results suggest that the damage of enhanced UV-B on both species might be alleviated by water deficit. This alleviation is important for understanding the response of BSCs to UV-B radiation in future global climate change. This also provides novel insights into assessment damages of UV-B to BSC stability in arid and semiarid regions.

  9. Estimating Net Primary Productivity Beneath Snowpack Using Snowpack Radiative Transfer Modeling and Global Satellite Data

    Science.gov (United States)

    Barber, D. E.; Peterson, M. C.

    2002-05-01

    Sufficient photosynthetically active radiation (PAR) penetrates snow for plants to grow beneath snowpack during late winter or early spring in tundra ecosystems. During the spring in this ecosystem, the snowpack creates an environment with higher humidity and less variable and milder temperatures than on the snow-free land. Under these conditions, the amount of PAR available is likely to be the limiting factor for plant growth. Current methods for determining net primary productivity (NPP) of tundra ecosystems do not account for this plant growth beneath snowpack, apparently resulting in underestimating plant production there. We are currently in the process of estimating the magnitude of this early growth beneath snow for tundra ecosystems. Our method includes a radiative transfer model that simulates diffuse and direct PAR penetrating snowpack based on downwelling PAR values and snow depth data from global satellite databases. These PAR levels are convolved with plant growth for vegetation that thrives beneath snowpacks, such as lichen. We expect to present the net primary production for Cladonia species (a common Arctic lichen) that has the capability of photosynthesizing at low temperatures beneath snowpack. This method may also be used to study photosynthesis beneath snowpacks in other hardy plants. Lichens are used here as they are common in snow-covered regions, flourish under snowpack, and provide an important food source for tundra herbivores (e.g. caribou). In addition, lichens are common in arctic-alpine environments and our results can be applied to these ecosystems as well. Finally, the NPP of lichen beneath snowpack is relatively well understood compared to other plants, making it ideal vegetation for this first effort at estimating the potential importance of photosynthesis at large scales. We are examining other candidate plants for their photosynthetic potential beneath snowpack at this time; however, little research has been done on this topic. We

  10. Earth Radiation Budget Experiment (ERBE) Data Sets for Global Environment and Climate Change Studies

    Science.gov (United States)

    Bess, T. Dale; Carlson, Ann B.; Denn, Fredrick M.

    1997-01-01

    For a number of years there has been considerable interest in the earth's radiation budget (ERB) or energy balance, and entails making the best measurements possible of absorbed solar radiation, reflected shortwave radiation (RSW), thermal outgoing longwave radiation (OLR), and net radiation. ERB data are fundamental to the development of realistic climate models and studying natural and anthropogenic perturbations of the climate. Much of the interest and investigations in the earth's energy balance predated the age of earth-orbiting satellites (Hunt et al., 1986). Beginning in the mid 1960's earth-orbiting satellites began to play an important role in making measurements of the earth's radiation flux although much effort had gone into measuring ERB parameters prior to 1960 (House et al., 1986). Beginning in 1974 and extending until the present time, three different satellite experiments (not all operating at the same time) have been making radiation budget measurements almost continually in time. Two of the experiments were totally dedicated to making radiation budget measurements of the earth, and the other experiment flown on NOAA sun-synchronous AVHRR weather satellites produced radiation budget parameters as a by-product. The heat budget data from the AVHRR satellites began collecting data in June 1974 and have operated almost continuously for 23 years producing valuable data for long term climate monitoring.

  11. Radiation-induced changes in carboxymethylated chitosan

    International Nuclear Information System (INIS)

    Huang Ling; Peng Jing; Zhai Maolin; Li Jiuqiang; Wei Genshuan

    2007-01-01

    This study focuses on the radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield (G d ) of CM-chitosan in solid state with N 2 -saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region

  12. Effect of solar radiation on drying house performance

    International Nuclear Information System (INIS)

    Rachmat, R.

    2000-01-01

    Solar drying is one of thermal utilization where radiation energy can be utilized efficiently. Solar drying of all sorts of agricultural products have been thoroughly studied and reported in literature, but brown rice drying system has not yet done as many as other products. The aim of the present study is to investigate the effect of solar radiation on drying house performance and brown rice drying characteristics. A construction of drying house is made from FRP sheets with 30 deg. of root slope faces southern part and inside the drying house is installed a flat bed dryer. The site of construction has 136 deg. 31.4'E in longitude and 34 deg. 43.8N in latitude with 3 m in elevation from sea level. The investigated parameters are global solar radiation, absorbed and net radiation and brown rice drying characteristics. The results showed that in unload condition, the air temperature inside drying house was higher (10 deg. C - 12 deg. C) than ambient air when there was not collector and temperature rise become higher (16 deg. C) when there was a black FRP collector inside drying house. The effect of solar radiation on temperature rise has the trend as a linear function. The heat collection efficiency of drying house with black FRP collector was two times higher (36.9 percent) than that without collector (16.3 percent). These phenomena exhibited significant result of collector utilization to the advantageous condition for a drying purpose [in

  13. Reversal of ocean acidification enhances net coral reef calcification.

    Science.gov (United States)

    Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; Maclaren, Jana K; Mason, Benjamin M; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

    2016-03-17

    Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO3(2-)]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO3(2-)], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

  14. Bio-dosimetry of ionizing radiation

    International Nuclear Information System (INIS)

    Hadjidekova, V.; Kristova, R.; Stainova, A.; Deleva, S.; Popova, L.; Georgieva, D.

    2013-01-01

    Full text: Introduction: The impact of ionizing radiation in medical, occupational and accidental human exposure leads to adverse side effects such as increased mortality and carcinogenesis. Information about the level of absorbed dose is important for risk assessment and for implementation of appropriate therapy. In most cases of actual or suspected exposure to ionizing radiation biological dosimetry is the only way to assess the absorbed dose. What you will learn: In this work we discuss the methods for biodosimetry and technological developments in their application in various emergency situations. The application of biological dosimetry and assessment of the influence of external factors in the conduct of epidemiological studies of radiation effects in protracted low-dose ionizing radiation on humans is presented. Discussion: The results of cytogenetic analysis and biological evaluation of absorbed dose based on the analysis of dicentrics in peripheral blood lymphocytes of five people injured in a severe radiation accident in Bulgaria in 2011 are presented. The assessed individual doses of the injured persons are in the range of 1.2 to 5,2 Gy acute homogeneous irradiation and are in line with the estimates of international experts. Conclusion: An algorithm to conduct a biological assessment of the dose in limited radiation accidents and in large scale radiation accidents with large number irradiated or suspected for exposure persons is proposed

  15. Absorbing Property of Multi-layered Short Carbon Fiber Absorbing Coating

    OpenAIRE

    Liu, Zhaohui; Tao, Rui; Ban, Guodong; Luo, Ping

    2018-01-01

    The radar absorbing coating was prepared with short carbon fiber asabsorbent and waterborne polyurethane (WPU) as matrix resin. The coating’s absorbing property was tested with vectornetwork analyzer, using aramid honeycomb as air layer which was matched withcarbon fiber coating. The results demonstrate that the single-layered carbonfiber absorbing coating presented relatively poor absorbing property when thelayer was thin, and the performance was slightly improved after the matched airlayer ...

  16. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  17. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    International Nuclear Information System (INIS)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A.

    2015-10-01

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  18. Discrimination of various contributions to the absorbed dose in BNCT: Fricke-gel imaging and intercomparison with other experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. E-mail: grazia.gambarini@mi.infn.it; Agosteo, S.; Marchesi, P.; Nava, E.; Palazzi, P.; Pecci, A.; Rosi, G.; Tinti, R

    2000-11-15

    A method is described for the 3D measurements of absorbed dose in a ferrous sulphate gel phantom, exposed in the thermal column of a nuclear reactor. The method, studied for Boron Neutron Capture Therapy (BNCT) purposes, allows absorbed dose imaging and profiling, with the separation of different contributions coming from different secondary radiations, generated from thermal neutrons. In fact, the biological effectiveness of the different radiations is different. Tests with conventional dosimeters were performed too.

  19. Thermophysical properties of polyethylene modified under γ radiation

    International Nuclear Information System (INIS)

    Shut, N.I.; Musaelyan, I.N.; Besklubenko, Yu.D.; Karpovich, N.B.; Kasperskij, A.V.

    1986-01-01

    Thermophysical properties (thermal conductivity, specific heat) of polyethylene (PE) modified under gamma radiation were studied. Thermophysical parameter dependences on the temperature (-100-+100 deg C) and an absorbed radiation dose are given. Degree of polymere crystallinity using a structural method for determination of the crystallinity degree by density was ascertained. It is shown that the PE thermophysical characteristics correlate to a value of absorbed gamma radiation dose, therefore gamma radiation can be recommended as a modifying factor for the production of polymer materials with the given properties

  20. Evaluation of absorbed doses at the interface solid surfaces - tritiated water solutions

    International Nuclear Information System (INIS)

    Postolache, Cristian; Matei, Lidia

    2003-01-01

    Studies concerning the isotopic exchange H/D/T in the system elemental hydrogen -- water and in the presence of platinum metals on hydrophobic supports as catalysts were carried out at ICSI (Institute of Cryogenics and Isotope Separations) - Rm. Valcea, Romania. Due to the very low energy of β-radiation emitted by tritium, the direct measurements of dose absorbed by the isotopic exchange catalyst using classical methods is practically impossible. For this purpose an evaluation model was developed. The volume of tritiated water which can irradiate the catalyst was represented by a hemisphere with the radius equal to the maximal rate of β-radiation emitted by tritium. The catalyst surface is represented by a circle with a 0.2 μm radius and the same centre as the circle of the hemisphere secant plane. Flow rate of absorbed dose is calculated with the relation: d (1/100)(Φ·E m /m), where d = dose flow rate, in rad/s, Φ total radiation flux interacting with the catalyst surface, expressed in erg and m = catalyst weight, in grams. Total flux of available radiation, Φ, was determined as a function of three parameters: a) total flow of tritium β-radiation emitted in the hemisphere of tritiated water, dependent on the volume and radioactive concentration; b) emission coefficient in the direction of the catalyst surface; c) attenuation coefficient (due to self-absorption) of the tritium β-radiation in the tritiated water body. (authors)

  1. Quantification of radiation absorbed dose and DNA damages in subjects undergoing computer tomography imaging

    International Nuclear Information System (INIS)

    Kanagaraj, Karthik; Basheerudeen, Safa Abdul Syed; Tamizh Selvan, G.; Venkatachalam, Perumal; Jose, M.T.; Ozhimuthu, Annalakshmi; Panneer Selvam, S.; Pattan, Sudha

    2014-01-01

    X-rays are extensively used in medical field for imaging, diagnostic radiology and radiotherapy. Irrespective of the application, the procedures deliver a significant amount of dose to the subject, while undergoing the procedure, which vary from imaging (low dose in the order mGy) and therapy (high doses in the order of several Gy). Of the various imaging modalities, the computed tomography (CT) is commonly used to diagnose many health alignments, in all age groups. Though the personals involved in performing the procedures are monitored for the levels of exposure, it is uncommon to monitor the patient after the examination, as the benefits outweigh the risk. However an enhanced concern on the risk associated due to the exposure of low dose X-radiation in CT has been reported. Therefore, we aim to quantify the absorbed dose to the eye, thyroid and forehead using thermo luminescence dosimeter of Lithium Manganese Borate doped with Terbium (LMB:Tb) in subjects undergoing CT examination (n= 27), as a methodology to investigate the effects of low dose ionizing radiation. Further, the DNA damages was measured using chromosomal aberration (CA) and micronucleus (MN) assay, from the blood samples obtained from the study subjects before and after the procedures. The overall measured organ dose ranged between 1.92 and 520.14 mGy for eye, 0.84 and 210.33 mGy for forehead and 1.79-185 mGy for thyroid, with an average of 128.86 1 137.16, 78.25 1 69.02 and 48.86 1 63.60 respectively. The DNA damages measured using CA and MN assay, showed an extreme statistically significant (p<0.0001) increase in CA and significant increase (p<0.001) in MN frequency in post exposure when compared to that of unexposed control. The significance of the estimated dose and the DNA damages will be discussed. (author)

  2. Linear accelerator with x-ray absorbing insulators

    International Nuclear Information System (INIS)

    Rose, P.H.

    1975-01-01

    Annular insulators for supporting successive annular electrodes in a linear accelerator have embedded x-ray absorbing shield structures extending around the accelerating path. The shield members are disposed to intercept x-ray radiation without disrupting the insulative effect of the insulator members. In preferred forms, the structure comprises a plurality of annular members of heavy metal disposed in an x-ray blocking array, spaced from each other by the insulating substance of the insulator member. (auth)

  3. SU-F-J-56: The Connection Between Cherenkov Light Emission and Radiation Absorbed Dose in Proton Irradiated Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Darafsheh, A; Kassaee, A; Finlay, J [University of Pennsylvania, Philadelphia, PA (United States); Taleei, R [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Range verification in proton therapy is of great importance. Cherenkov light follows the photon and electron energy deposition in water phantom. The purpose of this study is to investigate the connection between Cherenkov light generation and radiation absorbed dose in a water phantom irradiated with proton beams. Methods: Monte Carlo simulation was performed by employing FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and Cherenkov radiation in water phantoms. The simulations were performed for proton beams with energies in the range 50–600 MeV to cover a wide range of proton energies. Results: The mechanism of Cherenkov light production depends on the initial energy of protons. For proton energy with 50–400 MeV energy that is below the threshold (∼483 MeV in water) for Cherenkov light production directly from incident protons, Cherenkov light is produced mainly from the secondary electrons liberated as a result of columbic interactions with the incident protons. For proton beams with energy above 500 MeV, in the initial depth that incident protons have higher energy than the Cherenkov light production threshold, the light has higher intensity. As the slowing down process results in lower energy protons in larger depths in the water phantom, there is a knee point in the Cherenkov light curve vs. depth due to switching the Cherenkov light production mechanism from primary protons to secondary electrons. At the end of the depth dose curve the Cherenkov light intensity does not follow the dose peak because of the lack of high energy protons to produce Cherenkov light either directly or through secondary electrons. Conclusion: In contrast to photon and electron beams, Cherenkov light generation induced by proton beams does not follow the proton energy deposition specially close to the end of the proton range near the Bragg peak.

  4. Ionizing radiation interactions with DNA: nanodosimetry

    International Nuclear Information System (INIS)

    Bug, Marion; Nettelbeck, Heidi; Hilgers, Gerhard; Rabus, Hans

    2011-01-01

    The metrology of ionizing radiation is based on measuring values that are averaged over macroscopic volume elements, for instance the energy dose is defined as ratio of the energy deposited on the absorber and the absorber mass. For biological or medical radiation effects the stochastic nature of radiation interaction id of main importance, esp. the interaction of ionizing radiation with the DNA as the genetic information carrier. For radiotherapy and risk evaluation purposes a comprehensive system of radiation weighing factors and other characteristics, like radiation quality or relative biological efficacy was developed. The nanodosimetry is aimed to develop a metrological basis relying on physical characteristics of the microscopic structure of ionizing radiation tracks. The article includes the development of experimental nanodosimetric methods, the respective calibration techniques, Monte-Carlo simulation of the particle track microstructure and the correlation nanodosimetry and biological efficiency.

  5. Effects of ultraviolet-B radiation (UV-B) on growth and physiology of the dune grassland species Calamagrostis epigeios

    International Nuclear Information System (INIS)

    Tosserams, M.; Rozema, J.

    1995-01-01

    Seedlings of Calamagrostis epigeios were exposed to four levels of UV-B radiation (280-320 nm), simulating up to 44% reduction of stratospheric ozone concentration during summertime in The Netherlands, to determine the response of this plant species to UV-B irradiation. After six weeks of UV-B treatment, total biomass of all UV-B treated plants was higher, compared to plants that had received no UV-B radiation. The increase of biomass did not appear to be the result of a stimulation of net photosynthesis. Also, transpiration rate and water use efficiency were not altered by UV-B at any exposure level. Pigment analysis of leaf extracts showed no effect of enhanced UV-B radiation on chlorophyll content and accumulation of UV absorbing pigments. UV-B irradiance, however, did reduce the transmittance of visible light (400-700 nm) of intact attached leaves, suggesting a change in anatomical characteristics of the leaves. Additionally, the importance of including an ambient UV-B treatment in indoor experiments is discussed

  6. Calorimetric dosimetry of reactor radiation

    International Nuclear Information System (INIS)

    Radak, B.; Markovic, V.; Draganic, I.

    1961-01-01

    Calorimetric dosimetry of reactor radiation is relatively new reactor dosimetry method and the number of relevant papers is rather small. Some difficulties in applying standard methods (chemical dosemeters, ionization chambers) exist because of the complexity of radiation. In general application of calorimetric dosemeters for measuring absorbed doses is most precise. In addition to adequate choice of calorimetric bodies there is a possibility of determining the yields of each component of the radiation mixture in the total absorbed dose. This paper contains a short review of the basic calorimetry methods and some results of measurements at the RA reactor in Vinca performed by isothermal calorimeter [sr

  7. Estimation of the soil heat flux/net radiation ratio based on spectral vegetation indexes in high-latitude Arctic areas

    International Nuclear Information System (INIS)

    Jacobsen, A.; Hansen, B.U.

    1999-01-01

    The vegetation communities in the Arctic environment are very sensitive to even minor climatic variations and therefore the estimation of surface energy fluxes from high-latitude vegetated areas is an important subject to be pursued. This study was carried out in July-August and used micro meteorological data, spectral reflectance signatures, and vegetation biomass to establish the relation between the soil heat flux/net radiation (G / Rn) ratio and spectral vegetation indices (SVIs). Continuous measurements of soil temperature and soil heat flux were used to calculate the surface ground heat flux by use of conventional methods, and the relation to surface temperature was investigated. Twenty-seven locations were established, and six samples per location, including the measurement of the surface temperature and net radiation to establish the G/Rn ratio and simultaneous spectral reflectance signatures and wet biomass estimates, were registered. To obtain regional reliability, the locations were chosen in order to represent the different Arctic vegetation communities in the study area; ranging from dry tundra vegetation communities (fell fields and dry dwarf scrubs) to moist/wet tundra vegetation communities (snowbeds, grasslands and fens). Spectral vegetation indices, including the simple ratio vegetation index (RVI) and the normalized difference vegetation index (NDVI), were calculated. A comparison of SVIs to biomass proved that RVI gave the best linear expression, and NDVI the best exponential expression. A comparison of SVIs and the surface energy flux ratio G / Rn proved that NDVI gave the best linear expression. SPOT HRV images from July 1989 and 1992 were used to map NDVI and G / Rn at a regional scale. (author)

  8. The effect of clouds on the earth's solar and infrared radiation budgets

    Science.gov (United States)

    Herman, G. F.; Wu, M.-L. C.; Johnson, W. T.

    1980-01-01

    The effect of global cloudiness on the solar and infrared components of the earth's radiation balance is studied in general circulation model experiments. A wintertime simulation is conducted in which the cloud radiative transfer calculations use realistic cloud optical properties and are fully interactive with model-generated cloudiness. This simulation is compared to others in which the clouds are alternatively non-interactive with respect to the solar or thermal radiation calculations. Other cloud processes (formation, latent heat release, precipitation, vertical mixing) were accurately simulated in these experiments. It is concluded that on a global basis clouds increase the global radiation balance by 40 W/sq m by absorbing longwave radiation, but decrease it by 56 W/sq m by reflecting solar radiation to space. The net cloud effect is therefore a reduction of the radiation balance by 16 W/sq m, and is dominated by the cloud albedo effect. Changes in cloud frequency and distribution and in atmospheric and land temperatures are also reported for the control and for the non-interactive simulations. In general, removal of the clouds' infrared absorption cools the atmosphere and causes additional cloudiness to occur, while removal of the clouds' solar radiative properties warms the atmosphere and causes fewer clouds to form. It is suggested that layered clouds and convective clouds over water enter the climate system as positive feedback components, while convective clouds over land enter as negative components.

  9. Patient absorbed dose and radiation risk in nuclear medicine

    International Nuclear Information System (INIS)

    Hetherington, E.; Cochrane, P.

    1992-01-01

    Since the introduction of technetium-99m labelled radiopharmaceuticals used as imaging agents in the nuclear medicine departments of Australian hospitals, patients have voiced concern about the effect of having radioactive materials injected into their bodies. The danger of X-ray exposure is widely known and well accepted, as is exposure to ultrasound, computed tomography scans and other imaging techniques. However, radioactivity is an unknown, and fear of the unknown can occasionally lead to patients refusing to undergo a nuclear medicine procedure. The authors emphasised that the radiation dose to a patient from a typical procedure would depend on the patient's medical history and treatment; the average dose being approximately 50 times the exposure received from the natural environmental background radiation. Furthermore, over an extended period the body can repair most minor damage caused by radiation, just as the body can repair the damage caused by sunburn resulting from too much exposure to sunlight. The risk of genetic effects as a result of a medical radiation dose is than very small

  10. Dielectric microwave absorbing material processed by impregnation of carbon fiber fabric with polyaniline

    Directory of Open Access Journals (Sweden)

    Luiza de Castro Folgueras

    2007-03-01

    Full Text Available It is a known fact that the adequate combination of components and experimental conditions may produce materials with specific requirements. This study presents the effect of carbon fiber fabric impregnation with polyaniline conducting polymer aiming at the radar absorbing material processing. The experiments consider the sample preparation with one and two impregnations. The prepared samples were evaluated by reflectivity measurements, in the frequency range of 8-12 GHz and scanning electron microscopy analyses. The correlation of the results shows that the quantity of impregnated material influences the performance of the processed microwave absorber. This study shows that the proposed experimental route provides flexible absorbers with absorption values of the incident radiation close to 87%.

  11. The METAS absorbed dose to water calibration service for high energy photon and electron beam radiotherapy

    International Nuclear Information System (INIS)

    Stucki, G.; Muench, W.; Quintel, H.

    2002-01-01

    Full text: The Swiss Federal Office of Metrology and Accreditation (METAS) provides an absorbed dose to water calibration service for reference dosimeters using 60 Co γ radiation, ten X-ray beam qualities between TPR 20,10 =0.639 and 0.802 and ten electron beam qualities between R 50 =1.75 gcm -2 and 8.54 gcm -2 . A 22 MeV microtron accelerator with a conventional treatment head is used as radiation source for the high energy photon and electron beams. The treatment head produces clinical beams. The METAS absorbed dose calibration service for high energy photons is based on a primary standard sealed water calorimeter of the Domen type, that is used to calibrate several METAS transfer standards of type NE2611A and NE2571A in terms of absorbed dose to water in the energy range from 60 Co to TPR 20,10 = 0.802. User reference dosimeters are compared with the transfer standards to give calibration factors in absorbed dose to water with an uncertainty of 1.0% for 60 Co γ radiation and 1.4% for higher energies (coverage factor k=2). The calibration service was launched in 1997. The calibration factors measured by METAS have been compared with those derived from the Code of Practice of the International Atomic Energy Agency using the calculated k Q factors listed in table 14. The comparison showed a maximum difference of 0.8% for the NE25611A and NE 2571A chambers. At 60 Co γ radiation the METAS primary standard of absorbed dose to water was bilaterally compared with the primary standards of the Bureau International des Poids et Mesures BIPM (Sevres) as well as of the National Research Council NRC (Canada). In either case the standards were in agreement within the comparison uncertainties. The METAS absorbed dose calibration service for high energy electron beams is based on a primary standard chemical dosimeter. A monoenergetic electron beam of precisely known particle energy and beam charge is totally absorbed in Fricke solution (ferrous ammonium sulphate) of a given

  12. Self Absorbed Fraction for Electrons and Beta Particles in Small Spherical Volumes

    International Nuclear Information System (INIS)

    Grosev, D.

    2003-01-01

    Absorbed fraction and target organ mass are important parameters of internal dosimetry calculations that define the geometry of the system. Standard MIRD (Medical Internal Radiation Dosimetry) formalism assumes that the absorbed fraction for non-penetrating radiations (e.g., electrons, beta particles) is 1. This may not be correct in cases where dimensions of organs/tissues are comparable with the ranges of electrons/beta particles. Such is the case for example in radiodine ablation of thyroid remnant tissue. In this work the self-absorbed fraction (source and target volumes are the same) for monoenergetic electrons and beta particles is calculated for small spherical volumes of various sizes and unit density. Absorbed fraction can be expressed as an integral of the product of two quantities: (a) Scaled beta dose point kernel (mean absorbed dose rate per activity of the point source in infinite homogenous medium), F β ; (b) special geometrical reduction factor (GRF). F β is calculated using EGS4 Monte Carlo (MC) code for transport of electrons and photons. MC source code calculates the deposition of energy inside concentric spherical shells around the isotropic point source of electrons/beta particles in infinite medium (water). Shell thickness was δr=0.02·X 90 , where X 90 represents the radius of the sphere inside which 90% of the source energy is absorbed. Number of concentric spherical shells was 100, 10000 electron histories were started in each program run, and 10 runs were repeated for statistical reason. Numerical integration of the product of F β , calculated by MC program, and GRF for sphere was done using Simpson method. Absorbed fractions were calculated for spheres with mass from 0.01-20 g (r = 0.13 - 1.68 cm). Results are given for monoenergetic electrons with kinetic energy T=0.2, 0.4, 1.0 MeV, and for three beta emitters 1 31I , 3 2P , 9 0Y . For quantitative dosimetric protocols in radioiodine ablation therapy, results for 1 31I are of

  13. Measurement of absorbed radiation doses during whole body irradiation for bone marrow transplants using thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Giordani, Adelmo Jose; Segreto, Helena Cristina Comodo; Segreto, Roberto Araujo; Medeiros, Regina Bitelli; Oliveira, Jose Salvador R. de

    2004-01-01

    The objective was to evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. Two-hundred CaSO 4 :Dy + teflon tablets were calibrated in air and in 'phantom'. These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {(10 ? 10) cm 2 field. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or 'phantom' were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of ± 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets. (author)

  14. Management of glioblastoma at safety-net hospitals.

    Science.gov (United States)

    Brandel, Michael G; Rennert, Robert C; Lopez Ramos, Christian; Santiago-Dieppa, David R; Steinberg, Jeffrey A; Sarkar, Reith R; Wali, Arvin R; Pannell, J Scott; Murphy, James D; Khalessi, Alexander A

    2018-04-24

    Safety-net hospitals (SNHs) provide disproportionate care for underserved patients. Prior studies have identified poor outcomes, increased costs, and reduced access to certain complex, elective surgeries at SNHs. However, it is unknown whether similar patterns exist for the management of glioblastoma (GBM). We sought to determine if patients treated at HBHs receive equitable care for GBM, and if safety-net burden status impacts post-treatment survival. The National Cancer Database was queried for GBM patients diagnosed between 2010 and 2015. Safety-net burden was defined as the proportion of Medicaid and uninsured patients treated at each hospital, and stratified as low (LBH), medium (MBH), and high-burden (HBH) hospitals. The impact of safety-net burden on the receipt of any treatment, trimodality therapy, gross total resection (GTR), radiation, or chemotherapy was investigated. Secondary outcomes included post-treatment 30-day mortality, 90-day mortality, and overall survival. Univariate and multivariate analyses were utilized. Overall, 40,082 GBM patients at 1202 hospitals (352 LBHs, 553 MBHs, and 297 HBHs) were identified. Patients treated at HBHs were significantly less likely to receive trimodality therapy (OR = 0.75, p < 0.001), GTR (OR = 0.84, p < 0.001), radiation (OR = 0.73, p < 0.001), and chemotherapy (OR = 0.78, p < 0.001) than those treated at LBHs. Patients treated at HBHs had significantly increased 30-day (OR = 1.25, p = 0.031) and 90-day mortality (OR = 1.24, p = 0.001), and reduced overall survival (HR = 1.05, p = 0.039). GBM patients treated at SNHs are less likely to receive standard-of-care therapies and have increased short- and long-term mortality. Additional research is needed to evaluate barriers to providing equitable care for GBM patients at SNHs.

  15. Calibration of ionization chambers and determination of the absorbed doses

    International Nuclear Information System (INIS)

    RANDRIANTSEHENO, H.F

    1996-01-01

    In order to further improve the accuracy of dosimetric measurements in radiation therapy, the IAEA and WHO supported the establishment of Secondary Standard Dosimetry Laboratory (SSDLs). These SSDLs bridge the gap between the primary measurement standards and the user of ionizing radiation by providing the latter with calibrations against the SSDLs' secondary standards and by giving technical advice and assistance. However, a properly calibrated dosimeter is just necessary first condition for the determination of the dose. It has been demonstrated that the success or failure of radiation treatment depends on the absorbed dose delivered to the tumour and that this should not vary by more than a few per cent from described values. [fr

  16. Design, construction and characterization of special ionization chambers for X radiation beams monitoring

    International Nuclear Information System (INIS)

    Yoshizumi, Maira Tiemi

    2010-01-01

    X radiation equipment may show fluctuations in the radiation beam intensity, as they are connected to the power net. These intensity variations can, in turn, modify the air kerma rate produced by this radiation beam. In a calibration laboratory, where radiation detectors (from clinics and hospital services) are calibrated, variations in the radiation beam intensity may cause an error in the absorbed dose determination. The monitor ionization chambers are used to verify the radiation beam intensity constancy, and to provide a correction for possible fluctuations. In this work, monitor ionization chambers for X radiation beams were designed, assembled and characterized. The developed ionization chambers have an innovative design, ring-shaped, with aluminium or graphite electrodes. These ring-shaped ionization chambers have the advantage of not interfering in the direct radiation beams. A double-volume ionization chamber with graphite electrodes was also developed. This ionization chamber is similar to the commercial monitor ionization chamber used in the Calibration Laboratory of the Instituto de Pesquisas Energeticas e Nucleares. All developed ionization chambers were tested in several standardized radiation beams and their performances were compared with those of commercial ionization chambers. The results show that two of the four ionization chambers developed showed performance comparable to that of the commercial ionization chambers tested. Besides presenting good results, the ionization chambers were designed and manufactured using low cost materials, which are easily found on the Brazilian market. (author)

  17. Method of absorbing UF6 from gaseous mixtures in alkamine absorbents

    International Nuclear Information System (INIS)

    Lafferty, R.H.; Smiley, S.H.; Radimer, K.J.

    1976-01-01

    A method is described for recovering UF 6 from gaseous mixtures by absorption in a liquid. The liquid absorbent must have a relatively low viscosity and at least one component of the absorbent is an alkamine having less than 3 carbon atoms bonded to the amino nitrogen, less than 2 of the carbon atoms other than those bonded to the amino nitrogen are free of the hydroxy radical and precipitate the absorbed uranium from the absorbent. At least one component of the absorbent is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2

  18. Robust optimization of a tandem grating solar thermal absorber

    Science.gov (United States)

    Choi, Jongin; Kim, Mingeon; Kang, Kyeonghwan; Lee, Ikjin; Lee, Bong Jae

    2018-04-01

    Ideal solar thermal absorbers need to have a high value of the spectral absorptance in the broad solar spectrum to utilize the solar radiation effectively. Majority of recent studies about solar thermal absorbers focus on achieving nearly perfect absorption using nanostructures, whose characteristic dimension is smaller than the wavelength of sunlight. However, precise fabrication of such nanostructures is not easy in reality; that is, unavoidable errors always occur to some extent in the dimension of fabricated nanostructures, causing an undesirable deviation of the absorption performance between the designed structure and the actually fabricated one. In order to minimize the variation in the solar absorptance due to the fabrication error, the robust optimization can be performed during the design process. However, the optimization of solar thermal absorber considering all design variables often requires tremendous computational costs to find an optimum combination of design variables with the robustness as well as the high performance. To achieve this goal, we apply the robust optimization using the Kriging method and the genetic algorithm for designing a tandem grating solar absorber. By constructing a surrogate model through the Kriging method, computational cost can be substantially reduced because exact calculation of the performance for every combination of variables is not necessary. Using the surrogate model and the genetic algorithm, we successfully design an effective solar thermal absorber exhibiting a low-level of performance degradation due to the fabrication uncertainty of design variables.

  19. Annual absorbed dose rate at the surface of 38 hot and mineral springs in Iran

    Energy Technology Data Exchange (ETDEWEB)

    Bahreyni Toosi, M.; Orougi, M.H.; Sadeghzadeh, A.; Aghamir, A.; Jomehzadeh, A.; Zare, H. [Mashhad Univ. of Medical Sciences, Medical Physics Dep., Faculty of Medicine (Iran, Islamic Republic of)

    2006-07-01

    Full text of publication follows: Measurement of background radiation is very important from different points of view especially to human health. In some cases exposure rate near hot and mineral springs are higher than those of normal areas. The high background radiation of hot and mineral springs is primarily due to the presence of very high amounts of Ra 226 and its decay products. In this research, environmental gamma radiation of hot and mineral springs in Khorasan, Mazandaran and Sareeyn town in Ardabil province have been measured. Equipment used in this work included: a survey meter (R.D.S. -110), a tripod and an aluminium frame to hold the survey meter horizontally.R.D.S. -110 is a microprocessor controlled detector. This survey meter has been designed for monitoring X and rays and radiation. Measurements were carried out at one meter above water level in the vicinity of hot and mineral springs. Dose rates were recorded for one hour. The average of all recorded dose rates over one hour period was taken as the exposure rate for each station. The results indicate that in Khorasan province the highest and lowest annual absorbed dose rates were equal to 10.80 mSv/y at Shanigarmab and 0.52 mSv/y at Nasradin source respectively. In Mazandaran province maximum and minimum exposure rates equal to 54.4 and 0.53 mSv/y were obtained at the surface of Talleshmahalleh and Ghormerz sources. Exposure rates at the vicinity of Sarein sources were not very different and ranged from 1.39 to 1.59 mSv/y. The results indicate that in Khorasan province Shahingarmab hot spring has the highest annual absorbed dose rate (10.80 mSv/y) and Nasraddin in Sarbisheh has the lowest level of radiation (0.62 mSv/y). In Mazandaran province Taleshmahalleh hot mineral spring has the highest annual absorbed dose rate (54.41 mSv/y) and Ghormerz mineral spring has the lowest radiation level (0.53 mSv/y). Also in Sareeyn (in Ardabil province) Abechashm source has the highest annual absorbed dose

  20. Radiation absorption and use by humid savanna grassland: assessment using remote sensing and modelling

    International Nuclear Information System (INIS)

    Roux, X. le; Gauthier, H.; Begue, A.; Sinoquet, H.

    1997-01-01

    The components of the canopy radiation balance in photosynthetically active radiation (PAR), phytomass and leaf area index (LAI) were measured during a complete annual cycle in an annually burned African humid savanna. Directional reflectances measured by a hand-held radiometer were used to compute the canopy normalized difference vegetation index (NDVI). The fraction f APAR of PAR absorbed by the canopy (APAR) and canopy reflectances were simulated by the scattering from arbitrarily inclined leaves (SAIL) and the radiation interception in row intercropping (RIRI) models. The daily PAR to solar radiation ratio was linearly related to the daily fraction of diffuse solar radiation with an annual value around 0.47. The observed f APAR was non-linearly related to NDVI. The SAIL model simulated reasonably well directional reflectances but noticeably overestimated f APAR during most of the growing season. Comparison of simulations performed with the 1D and 3D versions of the RIRI model highlighted the weak influence of the heterogeneous structure of the canopy after fire and of the vertical distribution of dead and green leaves on total f APAR . Daily f APAR values simulated by the 3D-RIRI model were linearly related to and 9.8% higher than observed values. For sufficient soil water availability, the net production efficiency ϵ n of the savanna grass canopy was 1.92 and 1.28 g DM MJ −1 APAR (where DM stands for dry matter) during early regrowth and mature stage, respectively. In conclusion, the linear relationship between NDVI and f APAR used in most primary production models operating at large scales may slightly overestimate f APAR by green leaves for the humid savanna biome. Moreover, the net production efficiency of humid savannas is close to or higher than values reported for the other major natural biomes. (author)

  1. Absorbed dose measurement by the MIRD system in the 131-I treated Thyroid Cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Woon; Lim, Sang Mu; Kim, Chang Hui; Kim, Ki Sub; Cho, Jong Sio; Jeong, Jin Sung; Park, Heung Kyu; Kwon, Oh Jin [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1995-12-01

    Medical Internal Radiation Dose(MIRD) schema was developed for calculating the absorbed dose from the administrated radiopharmaceuticals. With the biological distribution data and physical properties of the radionuclide, we can estimated the absorbed dose by the MIRD schema. For the thyroid cancer patients received high dose 131-I therapy, the absorbed dose to the bone marrow is limiting factor to the administered dose and the duration of admission is determined by the retained activity in the whole body. To the monitoring of whole body radioactivity, we used Eberline Smart 200 system using ionization chamber as a detector. With the time activity (Author).

  2. Radiation pressure: A possible cause for the superrotation of the Venusian atmosphere

    Science.gov (United States)

    Krause, J. L.

    1992-01-01

    The superrotation of the venusian atmosphere relative to the planet's surface has long been known. Yet the process by which this vigorous circulation is maintained is poorly understood. The purpose of this report is to show that a mechanism by which the solar radiation interacts with the cloudy atmosphere of Venus could be the principle cause of the superrotation. It has been long known that Venus has a high albedo due to the scattering (similar to the reflection process) of solar radiation by the cloud droplets in its atmosphere. The radiation not scattered, but intercepted by the planet and its atmosphere, is mainly absorbed within the cloud layers. Therefore, momentum (equal, more or less, to that of the solar radiation intercepted) is continually transferred to the venusian atmosphere. The atmospheric system presents a symmetrical surface (same radiation-matter interaction) toward the solar radiation at its morning and evening limbs. If the cross-sectional areas at both limbs were equal, the momentum transfer at the morning limb would decelerate the atmosphere's rotation while at the evening limb the same transfer would accelerate the rotation an equal amount. The net result of this is that the overall rate of rotation would be unchanged. Such a symmetrical configuration is not likely since the atmosphere must be warmed as it rotates across the planet's day hemisphere and cooled as it rotates across the planet's night hemisphere. This warming and cooling must result in a formation of an asymmetrical configuration. It is apparent that the momentum transfer at the evening limb must be greater than that at the morning limb because the atmosphere's greater cross section at the evening limb intercepts a greater amount of solar radiation. It should be noted that very little of the solar radiation is transmitted through the cloud layers, especially at or near the limbs where the atmospheric path length of the radiation is long. This net momentum transfer must be

  3. Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

    International Nuclear Information System (INIS)

    Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

    1986-01-01

    To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body

  4. Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2009-12-01

    Full Text Available "nBackground and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT and computed tomography (CT."nMaterials and Methods: Thermoluminescent dosimeters (TLD were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ."nResults: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin to 0.308 mGY (submandibular gland, linear tomography ranged from 0.048 mGY (Lens to 0.510 mGY (submandibular gland,CBCT ranged from 0.322 mGY (thyroid glad to 1.144 mGY (Parotid gland and in CT ranged from 2.495 mGY (sublingual gland to 3.424 mGY (submandibular gland. Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT."nConclusion: For obtaining 3-dimensional (3D information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.

  5. National pattern for the realization of the unit of the dose speed absorbed in air for beta radiation. (Method: Ionometer, cavity of Bragg-Gray implemented in an extrapolation chamber with electrodes of variable separation, exposed to a field of beta radiation of 90Sr/90Y)

    International Nuclear Information System (INIS)

    Alvarez R, M. T.; Morales P, J. R.

    2001-01-01

    From the year of 1987 the Department of Metrology of the ININ, in their Secondary Laboratory of Calibration Dosimetric, has a patron group of sources of radiation beta and an extrapolation chamber of electrodes of variable separation.Their objective is to carry out of the unit of the dose speed absorbed in air for radiation beta. It uses the ionometric method, cavity Bragg-Gray in the extrapolation chamber with which it counts. The services that offers are: i) it Calibration : Radioactive Fuentes of radiation beta, isotopes: 90 Sr/ 90 Y; Ophthalmic applicators 9 0 S r/ 90 Y; Instruments for detection of beta radiation with to the radiological protection: Ionization chambers, Geiger-Muller, etc.; Personal Dosemeters. ii) Irradiation with beta radiation of materials to the investigation. (Author)

  6. The estimation of the control rods absorber burn-up during the VVER-1000 operation

    Energy Technology Data Exchange (ETDEWEB)

    Bolshagin, Sergey N.; Gorodkov, Sergey S.; Sukhino-Khomenko, Evgeniya A. [National Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2013-09-15

    The isotopic composition of the control rods absorber changes under the neutron flux influence, so the control rods efficiency can decrease. In the VVER-1000 control rods boron carbide and dysprosium titanate are used as absorbing materials. In boric part the efficiency decreases due to the {sup 10}B isotope burn-up. Dysprosium isotopes turn into other absorbing isotopes, so the absorbing properties of dysprosium part decrease to a lesser degree. Also the control rod's shells may be deformed as a consequence of boron carbide radiation swelling. This fact should be considered in substantiation of control rods durability. For the estimation of the control rods absorber burn-up two models are developed: VVER-1000 3-D fuel assembly with control rods partially immersed (imitation of the control rods operation in the working group) and VVER-1000 3-D fuel assembly with control rods, located at the upper limit switch (imitation of the control rods operation in groups of the emergency shutdown system). (orig.)

  7. Global aspects of radiation memory

    International Nuclear Information System (INIS)

    Winicour, J

    2014-01-01

    Gravitational radiation has a memory effect represented by a net change in the relative positions of test particles. Both the linear and nonlinear sources proposed for this radiation memory are of the ‘electric’ type, or E mode, as characterized by the even parity of the polarization pattern. Although ‘magnetic’ type, or B mode, radiation memory is mathematically possible, no physically realistic source has been identified. There is an electromagnetic counterpart to radiation memory in which the velocity of charged test particles obtain a net ‘kick’. Again, the physically realistic sources of electromagnetic radiation memory that have been identified are of the electric type. In this paper, a global null cone description of the electromagnetic field is applied to establish the non-existence of B-mode radiation memory and the non-existence of E-mode radiation memory due to a bound charge distribution. (paper)

  8. International trade causes large net economic losses in tropical countries via the destruction of ecosystem services.

    Science.gov (United States)

    Chang, Junning; Symes, William S; Lim, Felix; Carrasco, L Roman

    2016-05-01

    Despite the large implications of the use of tropical land for exports ("land absorption") on ecosystem services (ES) and global biodiversity conservation, the magnitude of these externalities is not known. We quantify the net value of ES lost in tropical countries as a result of cropland, forestland and pastureland absorption for exports after deducting ES gains through imports ("land displacement"). We find that net ES gains occur only in 7 out of the 41 countries and regions considered. We estimate global annual net losses of over 1.7 x 10(12) international dollars (I$) (I$1.1 x 10(12) if carbon-related services are not considered). After deducting the benefits from agricultural, forest and livestock rents in land replacing tropical forests, the net annual losses are I$1.3 and I$0.7 x 10(12), respectively. The results highlight the large magnitude of tropical ES losses through international trade that are not compensated by the rents of land uses in absorbed land.

  9. External dosimetry - Applications to radiation protection

    International Nuclear Information System (INIS)

    Faussot, Alain

    2011-01-01

    Dosimetry is the essential component of radiation protection. It allows to determine by calculation and measurement the absorbed dose value, i.e. the energy amounts deposited in matter by ionizing radiations. It deals also with the irradiation effects on living organisms and with their biological consequences. This reference book gathers all the necessary information to understand and master the external dosimetry and the metrology of ionizing radiations, from the effects of radiations to the calibration of radiation protection devices. The first part is devoted to physical dosimetry and allows to obtain in a rigorous manner the mathematical formalisms leading to the absorbed dose for different ionizing radiation fields. The second part presents the biological effects of ionizing radiations on living matter and the determination of a set of specific radiation protection concepts and data to express the 'risk' to develop a radio-induced cancer. The third part deals with the metrology of ionizing radiations through the standardized study of the methods used for the calibration of radiation protection equipments. Some practical exercises with their corrections are proposed at the end of each chapter

  10. Corrosion protection of PVD and paint coatings for selective solar absorber surfaces

    OpenAIRE

    Nunes, A.; Carvalho, M. J.; Diamantino, Teresa C.; Fernandes, J. C. S.

    2015-01-01

    The selective solar absorber surface is a fundamental part of a solar thermal collector, as it is responsible for the solar radiation absorption and for reduction of radiation heat losses. The surface’s optical properties, the solar absorption (á) and the emittance (å), have great impact on the solar thermal collector efficiency. In this work, two coatings types were studied: coatings obtained by physical vapor deposition (PVDs) and coatings obtained by projection with different paints (PCs) ...

  11. Does a leaf absorb radiation in the near infrared (780-900 nm) region? A new approach to quantifying optical reflection, absorption and transmission of leaves.

    Science.gov (United States)

    Merzlyak, Mark N; Chivkunova, Olga B; Melø, T B; Naqvi, K Razi

    2002-01-01

    The following question is addressed here: do healthy leaves absorb, as the spectra published over the last 50 years indicate, some 5-20% of incident radiation in the 780-900 nm region? The answer is found to be negative, and previous findings result from incomplete collection of the transmitted light by the detection system (even when the leaf is placed next to, but outside, the entrance port of an integrating sphere). A simple remedy for this inherent flaw in the experimental arrangement is applied successfully to leaves (of 10 unrelated species) differing in thickness, age and pigment content. The study has shown that, from an optical standpoint, a leaf tissue is a highly scattering material, and the infinite reflectance of a leaf is exceedingly sensitive to trace amounts of absorbing components. It is shown that water contributes, in a thick leaf (Kalanchoe blossfeldiana), an easily detectable signal even in the 780-900 nm region. The practical benefits resulting from improved measurements of leaf spectra are pointed out.

  12. Absorbed Dose and Effective Dose for Lung Cancer Image Guided Radiation Therapy(IGRT) using CBCT and 4D-CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Yong; Lee, Woo Suk; Koo, Ki Lae; Kim, Joo Seob; Lee, Sang Hyeon [Dept. of Radiation Oncology, GangNeung Asan Hospital, Gangneung (Korea, Republic of)

    2016-06-15

    To evaluate the results of absorbed and effective doses using CBCT and 4D-CBCT settings for lung cancer. This experimental study. Measurements were performed using a Anderson rando phantom with OSLD(optically stimulated luminescent dosimeters). It was performed computed tomography(Lightspeed GE, USA) in order to express the major organs of the human body. Measurements were obtained a mean value is repeated three times each. Evaluations of effective dose and absorbed dose were performed the CL-IX-Thorax mode and Truebeam-Thorax mode CBCT. Additionally, compared Truebeam-Thorax mode CBCT with Truebeam-Thorax mode 4D-CBCT(Four-dimensional Cone Beam Computed Tomography). Average absorbed dose in the CBCT of CL-IX was measured in lung 2.505cGy, heart 2.595cGy, liver 2.145cGy, stomach 1.934cGy, skin 2.233cGy, in case of Truebeam, It was measured lung 1.725cGy, heart 2.034cGy, liver 1.616cGy, stomach 1.470cGy, skin 1.445cGy. In case of 4D-CBCT, It was measured lung 3.849cGy, heart 4.578cGy, liver 3.497cGy, stomach 3.179cGy, skin 3.319cGy Average effective dose, considered tissue weighting and radiation weighting, in the CBCT of CL-IX was measured lung 2.164mSv, heart 2.241mSVv, liver 0.136mSv, stomach 1.668mSv, skin 0.009mSv, in case of Turebeam, it was measured lung 1.725mSv, heart 1.757mSv, liver 0.102mSv, stomach 1.270mSv, skin 0.005mSv, In case of 4D-CBCT, It was measured lung 3.326mSv, heart 3.952mSv, liver 0.223mSv, stomach 2.747mSv, skin 0.013mSv. As a result, absorbed dose and effective Dose in the CL-IX than Truebeam was higher about 1.3 times and in the 4D-CBCT Truebeam than CBCT of Truebeam was higher about 2.2times However, a large movement of the patient and respiratory gated radiotherapy may be more accurate treatment in 4D-CBCT. Therefore, it will be appropriate to selectively used.

  13. Characterization of beta radiation fields using radiochromic films

    International Nuclear Information System (INIS)

    Benavente, Jhonny A.; Silva, Teogenes A. da

    2011-01-01

    The objective of this work was to study the response of radiochromic films for beta radiation fields in terms of absorbed dose. The reliability of the EBT model Gafchromic radiochromic film was studied. A 9800 XL model Microtek, transmission scanner, a 369 model X-Rite optical densitometer and a Mini 1240 Shimadzu UV spectrophotometer were used for measurement comparisons. Calibration of the three systems was done with irradiated samples of radiochromic films with 0.1; 0.3; 0.5; 0.8; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.5 e 5.0 Gy in beta radiation field from a Sr-90/Y-90 source. Calibration was performed by establishing a correlation between the absorbed dose values and the corresponding radiochromic responses. Results showed significant differences in the absorbed dose values obtained with the three methods. Absorbed dose values showed errors from 0.6 to 4.4%, 0.3 to 31.8% and 0.2 to 47.3% for the Microtek scanner, the X-Rite Densitometer and the Shimadzu spectrophotometer, respectively. Due to the easy acquisition and use for absorbed dose measurements, the densitometer and the spectrophotometer showed to be suitable techniques to evaluate radiation dose in relatively homogeneous fields. In the case of inhomogeneous fields or for a two dimension mapping of radiation fields to identify anisotropies, the scanner technique is the most recommended. (author)

  14. 29 CFR 1910.1096 - Ionizing radiation.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 6 2010-07-01 2010-07-01 false Ionizing radiation. 1910.1096 Section 1910.1096 Labor... Ionizing radiation. (a) Definitions applicable to this section. (1) Radiation includes alpha rays, beta... the quantity of ionizing radiation absorbed, per unit of mass, by the body or by any portion of the...

  15. The absorbed dose to blood from blood-borne activity

    International Nuclear Information System (INIS)

    Hänscheid, H; Fernández, M; Lassmann, M

    2015-01-01

    The radiation absorbed dose to blood and organs from activity in the blood is relevant for nuclear medicine dosimetry and for research in biodosimetry. The present study provides coefficients for the average absorbed dose rates to the blood from blood-borne activity for radionuclides frequently used in targeted radiotherapy and in PET diagnostics. The results were deduced from published data for vessel radius-dependent dose rate coefficients and reasonable assumptions on the blood-volume distribution as a function of the vessel radius. Different parts of the circulatory system were analyzed separately. Vessel size information for heart chambers, aorta, vena cava, pulmonary artery, and capillaries was taken from published results of morphometric measurements. The remaining blood not contained in the mentioned vessels was assumed to reside in fractal-like vascular trees, the smallest branches of which are the arterioles or venules. The applied vessel size distribution is consistent with recommendations of the ICRP on the blood-volume distribution in the human. The resulting average absorbed dose rates to the blood per nuclear disintegration per milliliter (ml) of blood are (in 10 −11  Gy·s −1 ·Bq −1 ·ml) Y-90: 5.58, I-131: 2.49, Lu-177: 1.72, Sm-153: 2.97, Tc-99m: 0.366, C-11: 4.56, F-18: 3.61, Ga-68: 5.94, I-124: 2.55. Photon radiation contributes 1.1–1.2·10 −11  Gy·s −1 ·Bq −1 ·ml to the total dose rate for positron emitters but significantly less for the other nuclides. Blood self-absorption of the energy emitted by ß-particles in the whole blood ranges from 37% for Y-90 to 80% for Tc-99m. The correspondent values in vascular trees, which are important for the absorbed dose to organs, range from 30% for Y-90 to 82% for Tc-99m. (paper)

  16. RadNet Map Interface for Near-Real-Time Radiation Monitoring Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet is a national network of monitoring stations that regularly collect air, precipitation, drinking water, and milk samples for analysis of radioactivity. The...

  17. Absorber design for a Scheffler-Type Solar Concentrator

    International Nuclear Information System (INIS)

    Ruelas, José; Palomares, Juan; Pando, Gabriel

    2015-01-01

    Highlights: • Receiver and absorber design methodology based in a solar image in the focal surface. • Stirling absorber dimensions based in a solar image in the focal surface of a STSC. • Comparative study of a solar image in the focal surface from different optical model. • A Monte-Carlo ray-tracing method was used to set STSC cavity receiver aperture. - Abstract: Ray tracing software, digital close range photogrammetry and the Monte-Carlo ray-tracing method have proven to be precise and efficient measurement techniques for the assessment of the shape accuracies of solar concentrators and their components. This paper presents a new method and results for the geometric aspect of a focal image for a Scheffler-Type Solar Concentrator (STSC) using ray tracing, digital close range photogrammetry and the Monte-Carlo ray-tracing method to establish parameters that allow for the design of the most suitable absorber and receiver geometry for coupling the STSC to a Stirling engine. The results of the ray tracing software, digital close range photogrammetry and Monte-Carlo ray tracing technique in STSC are associated with a Stirling receiver. When using the method to perform simulations, we found that the most suitable solar image geometry has an elliptical shape and area of 0.0065 m 2 on average. Although this result is appropriate, the geometry of the receiver is modified to fit an absorber and cavity receiver to improve the heat transfer by radiation

  18. Radiation stress relieving of polymer articles

    International Nuclear Information System (INIS)

    Frisch, D.C.; Weber, W.

    1982-01-01

    A method of rapidly relieving stress in an extruded or molded polymer article is disclosed. The method can be used in the preparation of printed circuit boards. An article comprised of the polymer is exposed to electromagnetic radiation, for a time period sufficient to absorb enough energy to stress relieve the polymer against stress cracking therein. Exposure occurs at one or more ranges of frequencies which are capable of being absorbed by the polymer and which are effective for stress relieving without or substantially without causing heat induced softening or flowing of the polymer. The electromagnetic radiation is selected from the ranges of infrared, microwave or ultraviolet radiation

  19. Top-of-atmosphere radiative forcing affected by brown carbon in the upper troposphere

    Science.gov (United States)

    Zhang, Yuzhong; Forrister, Haviland; Liu, Jiumeng; Dibb, Jack; Anderson, Bruce; Schwarz, Joshua P.; Perring, Anne E.; Jimenez, Jose L.; Campuzano-Jost, Pedro; Wang, Yuhang; Nenes, Athanasios; Weber, Rodney J.

    2017-07-01

    Carbonaceous aerosols affect the global radiative balance by absorbing and scattering radiation, which leads to warming or cooling of the atmosphere, respectively. Black carbon is the main light-absorbing component. A portion of the organic aerosol known as brown carbon also absorbs light. The climate sensitivity to absorbing aerosols rapidly increases with altitude, but brown carbon measurements are limited in the upper troposphere. Here we present aircraft observations of vertical aerosol distributions over the continental United States in May and June 2012 to show that light-absorbing brown carbon is prevalent in the troposphere, and absorbs more short-wavelength radiation than black carbon at altitudes between 5 and 12 km. We find that brown carbon is transported to these altitudes by deep convection, and that in-cloud heterogeneous processing may produce brown carbon. Radiative transfer calculations suggest that brown carbon accounts for about 24% of combined black and brown carbon warming effect at the tropopause. Roughly two-thirds of the estimated brown carbon forcing occurs above 5 km, although most brown carbon is found below 5 km. The highest radiative absorption occurred during an event that ingested a wildfire plume. We conclude that high-altitude brown carbon from biomass burning is an unappreciated component of climate forcing.

  20. Absorbing Aerosols: Field and Laboratory Studies of Black Carbon and Dust

    Science.gov (United States)

    Aiken, A. C.; Flowers, B. A.; Dubey, M. K.

    2011-12-01

    Currently, absorbing aerosols are thought to be the most uncertain factor in atmospheric climate models (~0.4-1.2 W/m2), and the 2nd most important factor after CO2 in global warming (1.6 W/m2; Ramanathan and Carmichael, Nature Geoscience, 2008; Myhre, Science, 2009). While most well-recognized atmospheric aerosols, e.g., sulfate from power-plants, have a cooling effect on the atmosphere by scattering solar radiation, black carbon (BC or soot) absorbs sunlight strongly which results in a warming of the atmosphere. Dust particles are also present globally and can absorb radiation, contributing to a warmer and drier atmosphere. Direct on-line measurements of BC and hematite, an absorbing dust aerosol, can be made with the Single Particle Soot Photometer (SP2), which measures the mass of the particles by incandescence on an individual particle basis. Measurements from the SP2 are combined with absorption measurements from the three-wavelength photoacoustic soot spectrometer (PASS-3) at 405, 532, and 781 nm and the ultraviolet photoacoustic soot spectrometer (PASS-UV) at 375 nm to determine wavelength-dependent mass absorption coefficients (MACs). Laboratory aerosol samples include flame-generated soot, fullerene soot, Aquadag, hematite, and hematite-containing dusts. Measured BC MAC's compare well with published values, and hematite MAC's are an order of magnitude less than BC. Absorbing aerosols measured in the laboratory are compared with those from ambient aerosols measured during the Las Conchas fire and BEACHON-RoMBAS. The Las Conchas fire was a wildfire in the Jemez Mountains of New Mexico that burned over 100,000 acres during the Summer of 2011, and BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study) is a field campaign focusing on biogenic aerosols at the Manitou Forest Observatory near Colorado Springs, CO in Summer 2011. Optical properties and size

  1. A net normal dispersion all-fiber laser using a hybrid mode-locking mechanism

    International Nuclear Information System (INIS)

    Xu, Bo; Martinez, Amos; Yamashita, Shinji; Set, Sze Yun; Goh, Chee Seong

    2014-01-01

    We propose and demonstrate an all-fiber, dispersion-mapped, erbium-doped fiber laser with net normal dispersion generating dissipative solitons. The laser is mode-locked by a hybrid mode-locking mechanism consisting of a nonlinear amplifying loop mirror and a carbon nanotube saturable absorber. We achieve self-starting, mode-locked operation generating 2.75 nJ pulses at a fundamental repetition rate of 10.22 MHz with remarkable long term stability. (letter)

  2. Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La

    Directory of Open Access Journals (Sweden)

    Valdirene Aparecida da Silva

    2009-06-01

    Full Text Available Radar Absorbing Materials (RAM are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am2/kg and coercive field (0.07 T indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

  3. Radiation exposure during travelling in Malaysia

    International Nuclear Information System (INIS)

    Omar, M.; Hassan, A.; Sulaiman, I.

    2006-01-01

    Absorbed dose rates in vehicles during travelling by different modes of transport in Malaysia were measured. Radiation levels measured on roads in Peninsular Malaysia were within a broad range, i.e. between 36 and 1560 nGy h -1 . The highest reading, recorded while travelling near monazite and zircon mineral dumps, was 13 times the mean environmental radiation level of Malaysia. It is evident that radioactive material dumps on the roadsides can influence the radiation level on the road. The absorbed dose rates measured while travelling on an ordinary train were between 60 and 350 nGy h -1 . The highest reading was measured when the train passed a tunnel built through a granite rock hill. The measurement during sea travelling by ferries gave the lowest radiation level owing to merely cosmic radiation at the sea level. (authors)

  4. Radiative and convective properties of 316L Stainless Steel fabricated using the Laser Engineered Net Shaping process

    Science.gov (United States)

    Knopp, Jonathan

    Temperature evolution of metallic materials during the additive manufacturing process has direct influence in determining the materials microstructure and resultant characteristics. Through the power of Infrared (IR) thermography it is now possible to monitor thermal trends in a build structure, giving the power to adjust building parameters in real time. The IR camera views radiation in the IR wavelengths and determines temperature of an object by the amount of radiation emitted from the object in those wavelengths. Determining the amount of radiation emitted from the material, known as a materials emissivity, can be difficult in that emissivity is affected by both temperature and surface finish. It has been shown that the use of a micro-blackbody cavity can be used as an accurate reference temperature when the sample is held at thermal equilibrium. A micro-blackbody cavity was created in a sample of 316L Stainless Steel after being fabricated during using the Laser Engineered Net Shaping (LENS) process. Holding the sample at thermal equilibrium and using the micro-blackbody cavity as a reference and thermocouple as a second reference emissivity values were able to be obtained. IR thermography was also used to observe the manufacturing of these samples. When observing the IR thermography, patterns in the thermal history of the build were shown to be present as well as distinct cooling rates of the material. This information can be used to find true temperatures of 316L Stainless Steel during the LENS process for better control of desired material properties as well as future work in determining complete energy balance.

  5. MPL-net at ARM Sites

    Science.gov (United States)

    Spinhirne, J. D.; Welton, E. J.; Campbell, J. R.; Berkoff, T. A.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The NASA MPL-net project goal is consistent data products of the vertical distribution of clouds and aerosol from globally distributed lidar observation sites. The four ARM micro pulse lidars are a basis of the network to consist of over twelve sites. The science objective is ground truth for global satellite retrievals and accurate vertical distribution information in combination with surface radiation measurements for aerosol and cloud models. The project involves improvement in instruments and data processing and cooperation with ARM and other partners.

  6. Ultraviolet-B radiation absorbing capacity of leaf hairs

    International Nuclear Information System (INIS)

    Karabourniotis, G.; Papadopoulos, K.; Papamarkou, M.; Manetas, Y.

    1992-01-01

    Pubescence layers with their native structure and orientation were isolated from the leaves of Olea europaea L. and Olea chrysophylla L. They were almost transparent in the visible, but considerable absorptance was evident in the ultraviolet-B region (UV-B), with maximum at 310 nm. Methanolic extracts of hairs from Olea and a variety of other pubescent species consistently showed the existence of UV-screening pigments. Absorptance of trichomes varied, but a trend towards more effective UV-B radiation attenuation in the sub-alpine Verbascum species may be claimed. In all cases, pigments were located within hair cells and in Olea they were characterized as phenolics with considerable flavonoid contribution. It is suggested that leaf hairs, besides other functions, may constitute a shield against UV-B radiation. (author)

  7. Radiative budget and cloud radiative effect over the Atlantic from ship-based observations

    Directory of Open Access Journals (Sweden)

    J. Kalisch

    2012-10-01

    Full Text Available The aim of this study is to determine cloud-type resolved cloud radiative budgets and cloud radiative effects from surface measurements of broadband radiative fluxes over the Atlantic Ocean. Furthermore, based on simultaneous observations of the state of the cloudy atmosphere, a radiative closure study has been performed by means of the ECHAM5 single column model in order to identify the model's ability to realistically reproduce the effects of clouds on the climate system.

    An extensive database of radiative and atmospheric measurements has been established along five meridional cruises of the German research icebreaker Polarstern. Besides pyranometer and pyrgeometer for downward broadband solar and thermal radiative fluxes, a sky imager and a microwave radiometer have been utilized to determine cloud fraction and cloud type on the one hand and temperature and humidity profiles as well as liquid water path for warm non-precipitating clouds on the other hand.

    Averaged over all cruise tracks, we obtain a total net (solar + thermal radiative flux of 144 W m−2 that is dominated by the solar component. In general, the solar contribution is large for cirrus clouds and small for stratus clouds. No significant meridional dependencies were found for the surface radiation budgets and cloud effects. The strongest surface longwave cloud effects were shown in the presence of low level clouds. Clouds with a high optical density induce strong negative solar radiative effects under high solar altitudes. The mean surface net cloud radiative effect is −33 W m−2.

    For the purpose of quickly estimating the mean surface longwave, shortwave and net cloud effects in moderate, subtropical and tropical climate regimes, a new parameterisation was created, considering the total cloud amount and the solar zenith angle.

    The ECHAM5 single column model provides a surface net cloud effect that is more

  8. Horizontal ichthyoplankton tow-net system with unobstructed net opening

    Science.gov (United States)

    Nester, Robert T.

    1987-01-01

    The larval fish sampler described here consists of a modified bridle, frame, and net system with an obstruction-free net opening and is small enough for use on boats 10 m or less in length. The tow net features a square net frame attached to a 0.5-m-diameter cylinder-on-cone plankton net with a bridle designed to eliminate all obstructions forward of the net opening, significantly reducing currents and vibrations in the water directly preceding the net. This system was effective in collecting larvae representing more than 25 species of fish at sampling depths ranging from surface to 10 m and could easily be used at greater depths.

  9. 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.

  10. 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)

  11. Higher-moment measurements of net-kaon, net-charge and net-proton multiplicity distributions at STAR

    International Nuclear Information System (INIS)

    Sarkar, Amal

    2014-01-01

    In this paper, we report the measurements of the various moments, such as mean, standard deviation (σ), skewness (S) and kurtosis (κ) of the net-kaon, net-charge and net-proton multiplicity distributions at mid-rapidity in Au + Au collisions from √(s NN )=7.7 to 200 GeV with the STAR experiment at RHIC. This work has been done with the aim to locate the critical point on the QCD phase diagram. These moments and their products are related to the thermodynamic susceptibilities of conserved quantities such as net baryon number, net charge, and net strangeness as well as to the correlation length of the system which diverges in an ideal infinite thermodynamic system at the critical point. For a finite system, existing for a finite time, a non-monotonic behavior of these variables would indicate the presence of the critical point. Furthermore, we also present the moment products Sσ, κσ 2 of net-kaon, net-charge and net-proton multiplicity distributions as a function of collision centrality and energy. The energy and the centrality dependence of higher moments and their products have been compared with different models

  12. Aperiodic-metamaterial-based absorber

    Directory of Open Access Journals (Sweden)

    Quanlong Yang

    2017-09-01

    Full Text Available The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber, how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  13. Analysis of uncertainties in the measurements of absorbed dose to water in a secondary standard dosimetry laboratory (SSDL) 60Cobalt

    International Nuclear Information System (INIS)

    Silva, Cosme Norival Mello da; Rosado, Paulo Henrique Goncalves

    2011-01-01

    The National Metrology Laboratory of Ionizing Radiation (LNMRI) is the laboratory designated by INMETRO in the field of Metrology of ionizing radiation and is a Secondary Standard Dosimetry Laboratory (SSDL). One of its guidelines is to maintain and disseminate LNMRI absorbed dose in water used as a national standard dosimetry in radiotherapy. For this pattern is metrologically acceptable accuracy and uncertainties should be assessed over time. The objective of this study is to analyze the uncertainties involved in determining the absorbed dose rate in water and standard uncertainty of absorbed dose calibration in water from a clinical dosimeter. The largest sources of uncertainty in determining the rate of absorbed dose in water are due to: calibration coefficient of the calibration certificate supplied by the BIPM, electrometer calibration, camber stability over time, variation of pressure and humidity, strong dependence and non-uniformity of the field. The expanded uncertainty is 0.94% for k = 2. For the calibration standard uncertainty of absorbed dose in water of a dosimeter in a clinical a major source of uncertainty is due to the absorbed dose rate in water (0.94%). The value of expanded uncertainty of calibrating a clinical dosimeter is 1.2% for k = 2. (author)

  14. Staff and patient absorbed doses due to diagnostic nuclear medicine procedures

    International Nuclear Information System (INIS)

    Tabei, F.; Neshandar Asli, I.; Aghamiri, S.M.; Arbabi, K.

    2004-01-01

    Background: annual patient effective dose equivalent can be considered as a quantitative physical parameter describing the activities performed in each nuclear medicine department. annual staff dose equivalent could be also considered as a parameter describing the amount of radiation risk for performing the activities. We calculated the staff to patient dose equivalent ratio to be used as a physical parameter for quantification of ALARA law in nuclear medicine department. Materials and methods: as a part of nationwide study, this paper reports the staff and patient absorbed dose equivalents from diagnostic nuclear medicine examinations performed in four nuclear medicine department during 1999-2002. The type and frequency of examinations in each department were determined directly from hospital medical reports. Staff absorbed doses equivalents were calculated from regular personal dosimeter reports. Results: the total number of examinations increased by 16.7 % during these years. Annual patient collective dose equivalent increased about 13.0 % and the mean effective dose equivalent per exam was 3.61 ± 0.07 mSv. Annual total staff absorbed dose equivalent (total of 24 radiation workers) in four departments increased from 40.45 mSv to 47.81 mSv during four years that indicates an increase of about 20.6 %. The average of annual ratios of staff to patient effective dose equivalents in four departments were 1.83 x 10 -3 , 1.04 x 10 -3 , 3.28 x 10 -3 and 3.24 x 10 -3 , respectively, within a range of 0.9 x 10 -3 - 4.17 x 10 -3 . The mean value of ratios in four years was about 2.24 x 10 -3 ± 1.09 x 10 -3 that indicates the staff dose of about two 1000 th of patient dose. Conclusion: The mean value of ratios in four years was about 1.89 x 10 -3 ± 0.95 x 10 -3 indicating the staff dose of about one 1000 th of the patient dose. The staff to patient absorbed dose equivalent ratio could be used as a quantitative parameter for describing ALARA law in radiation protection and

  15. Optimized reflectors for non-tracking solar collectors with tubular absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Muschaweck, Julius [Optics and Energy Consulting, Munich (Germany); Spirkl, Wolfgang [Ludwig-Maximilians Univ., Sektion Physik, Munich (Germany); Timinger, Andreas [Optics and Energy Consulting, Munich (Germany); ZAE Bayern, Solar Thermal and Biomass Dept., Munich (Germany); Benz, Nikolaus; Doerfler, Michael; Gut, Martin [ZAE Bayern, Solar Thermal and Biomass Dept., Munich (Germany); Kose, Erwin [microtherm Energietecjnik GmbH, Lods, 25 (France)

    2000-07-01

    We present an approach to find optimal reflector shapes for non-tracking solar collectors under practical constraints. We focus on cylindrical absorbers and reflectors with translational symmetry. Under idealised circumstances, edge ray reflectors are well known to be optimal. However, it is not clear how optimal reflectors should be shaped in order to obtain maximum utilisable energy for given operating temperatures under practical constraints like reflectivity less than unity, real radiation data, size limits, and gaps between the reflector and the absorber. For a prototype collector with a symmetric edge ray reflector and a tubular absorber, we derive from calorimetric measurements under outdoor conditions the optical efficiency as a function of the incidence angle. Using numerical optimisation and raytracing, we compare truncated symmetric edge ray reflectors, truncated asymmetric edge ray reflectors and free forms parametrized by Bezier splines. We find that asymmetric edge ray reflectors are optimal. For reasonable operating conditions, truncated asymmetric edge ray reflectors allow much better land use and easily adapt to a large range of roof tilt angles with marginal changes in collector construction. Except near the equator, they should increase the yearly utilisable energy per absorber tube by several percent as compared to the prototype collector with symmetric reflectors. (Author)

  16. Aligned metal absorbers and the ultraviolet background at the end of reionization

    Science.gov (United States)

    Doughty, Caitlin; Finlator, Kristian; Oppenheimer, Benjamin D.; Davé, Romeel; Zackrisson, Erik

    2018-04-01

    We use observations of spatially aligned C II, C IV, Si II, Si IV, and O I absorbers to probe the slope and intensity of the ultraviolet background (UVB) at z ˜ 6. We accomplish this by comparing observations with predictions from a cosmological hydrodynamic simulation using three trial UVBs applied in post-processing: a spectrally soft, fluctuating UVB calculated using multifrequency radiative transfer; a soft, spatially uniform UVB; and a hard, spatially uniform `quasars-only' model. When considering our paired high-ionization absorbers (C IV/Si IV), the observed statistics strongly prefer the hard, spatially uniform UVB. This echoes recent findings that cosmological simulations generically underproduce strong C IV absorbers at z > 5. A single low/high ionization pair (Si II/Si IV), by contrast, shows a preference for the HM12 UVB, whereas two more (C II/C IV and O I/C IV) show no preference for any of the three UVBs. Despite this, future observations of specific absorbers, particularly Si IV/C IV, with next-generation telescopes probing to lower column densities should yield tighter constraints on the UVB.

  17. Winter Radiation Extinction and Reflection in a Boreal Pine Canopy: Measurements and Modelling

    Science.gov (United States)

    Pomeroy, J. W.; Dion, K.

    1996-12-01

    Predicting the rate of snowmelt and intercepted snow sublimation in boreal forests requires an understanding of the effects of snow-covered conifers on the exchange of radiant energy. This study examined the amount of intercepted snow on a jack pine canopy in the boreal forest of central Saskatchewan and the shortwave and net radiation exchange with this canopy, to determine the effect of intercepted snow and canopy structure on shortwave radiation reflection and extinction and net radiation attenuation in a boreal forest. The study focused on clear sky conditions, which are common during winter in the continental boreal forest. Intercepted snow was found to have no influence on the clear-sky albedo of the canopy, the extinction of short wave radiation by the canopy or ratio of net radiation at the canopy top to that at the surface snow cover. Because of the low albedo of the snow-covered canopy, net radiation at the canopy top remains positive and a large potential source of energy for sublimation. The canopy albedo declines somewhat as the extinction efficiency of the underlying canopy increases. The extinction efficiency of short wave radiation in the canopy depends on solar angle because of the approximately horizontal orientation of pine branches. For low solar angles above the horizon, the extinction efficiency is quite low and short wave transmissivity through the canopy is relatively high. As the solar angle increases, extinction increases up to angles of about 50̂, and then declines. Extinction of short wave radiation in the canopy strongly influences the attenuation of net radiation by the canopy. Short wave radiation that is extinguished by branches is radiated as long wave, partly downwards to the snow cover. The ratio of net radiation at the canopy top to that at the snow cover surface increases with the extinction of short wave radiation and is negative for low extinction efficiencies. For the pine canopy examined, the daily mean net radiation at the

  18. External exposure level from natural radiation and population dose in Gansu province

    International Nuclear Information System (INIS)

    Guo Shanxiang; Li Fuzeng; Jiao Yufang

    1985-01-01

    The resultts of measurement of absorbed dose rate in air from natural gamma radiation in Gansu measured with FD-71 scintillation radiometers are reported in this paper. Sketch maps of distribution of absorbed dose rates from natural radiation in this province are also presented. The mean values of absorbed rates in air from terrestrial gamma radiation for outdoors and indoors are 0.7 mGy/a (range 0.32 to 1.11 mGy/a) and 1.02 mGy/a (range 0.73 to 1.4 mGy/a), respectively. The annual effective dose equivalent from terrestrial gamma radiation to population in this province is estimated to be 1,14 mSv

  19. Absorbing rods for nuclear fast neutron reactor absorbing assembly

    International Nuclear Information System (INIS)

    Aji, M.; Ballagny, A.; Haze, R.

    1986-01-01

    The invention proposes a neutron absorber rod for neutron absorber assembly of a fast neutron reactor. The assembly comprises a bundle of vertical rods, each one comprising a stack of pellets made of a neutron absorber material contained in a long metallic casing with a certain radial play with regard to this casing; this casing includes traps for splinters from the pellets which may appear during reactor operation, at the level of contact between adjacent pellets. The present invention prevents the casing from rupture involved by the disintegration of the pellets producing pieces of boron carbide of high hardness [fr

  20. Parotid-Absorbed Doses: A Comparison Between Spiral Tomography and Panoramic

    Directory of Open Access Journals (Sweden)

    Ehsan Hekmatian

    2016-07-01

    Full Text Available Background Jaws spiral tomography and panoramic radiography have wide applications in dentistry, and the parotid gland is one of the most sensitive organs of the head and neck. Objectives The aim of this study was to evaluate and compare the parotid-absorbed dose in spiral tomography and panoramic radiographs using a thermoluminescent dosimeter. Materials and Methods A radiation analog dosimetry phantom was placed in a Cranex Tome radiograph device, and a parotid absorbed dose was measured in both techniques. Thermoluminescent dosimeters were placed bilaterally in the parotid region (on the tube side and the opposite side. Spiral tomography dosimetry was done for the upper and lower jaws in the anterior and posterior regions. Each region contained four slices of 2 mm and four slices of 4 mm in thickness. The results were analyzed by a Wilcoxon test. Results For the tube side parotid, the average absorbed doses in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.70/1.40 and 1.65/1.60 mGy, respectively. The average absorbed doses with the 4mm slices were 1.65/1.70 and 1.75/1.57 mGy, respectively. For the opposite parotid, the average absorbed dose in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.40/1.30 and 1.40/1.67 mGy, respectively. The average absorbed doses with the 4mm slices were 1.50/1.66 and 1.40/1.50 mGy, respectively. The average absorbed dose of the panoramic radiograph was 1.40 mGy. Conclusions There was no statistically significant difference in the parotid absorbed dose between spiral tomography and a panoramic radiograph (P value = 0.18. The overall results of this study were similar to other studies.

  1. 3D calculation of absorbed dose for 131I-targeted radiotherapy: A Monte Carlo study

    International Nuclear Information System (INIS)

    Saeedzadeh, E.; Sarkar, S.; Abbaspour Tehrani-Fard, A.; Ay, M. R.; Khosravi, H. R.; Loudos, G.

    2008-01-01

    Various methods, such as those developed by the Medical Internal Radiation Dosimetry (MIRD) Committee of the Society of Nuclear Medicine or employing dose point kernels, have been applied to the radiation dosimetry of 131 I radionuclide therapy. However, studies have not shown a strong relationship between tumour absorbed dose and its overall therapeutic response, probably due in part to inaccuracies in activity and dose estimation. In the current study, the GATE Monte Carlo computer code was used to facilitate voxel-level radiation dosimetry for organ activities measured in an. 131 I-treated thyroid cancer patient. This approach allows incorporation of the size, shape and composition of organs (in the current study, in the Zubal anthropomorphic phantom) and intra-organ and intra-tumour inhomogeneities in the activity distributions. The total activities of the tumours and their heterogeneous distributions were measured from the SPECT images to calculate the dose maps. For investigating the effect of activity distribution on dose distribution, a hypothetical homogeneous distribution of the same total activity was considered in the tumours. It was observed that the tumour mean absorbed dose rates per unit cumulated activity were 0.65 E-5 and 0.61 E-5 mGY MBq -1 s -1 for the uniform and non-uniform distributions in the tumour, respectively, which do not differ considerably. However, the dose-volume histograms (DVH) show that the tumour non-uniform activity distribution decreases the absorbed dose to portions of the tumour volume. In such a case, it can be misleading to quote the mean or maximum absorbed dose, because overall response is likely limited by the tumour volume that receives low (i.e. non-cytocidal) doses. Three-dimensional radiation dosimetry, and calculation of tumour DVHs, may lead to the derivation of clinically reliable dose-response relationships and therefore may ultimately improve treatment planning as well as response assessment for radionuclide

  2. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  3. Surface net solar radiation estimated from satellite measurements - Comparisons with tower observations

    Science.gov (United States)

    Li, Zhanqing; Leighton, H. G.; Cess, Robert D.

    1993-01-01

    A parameterization that relates the reflected solar flux at the top of the atmosphere to the net solar flux at the surface in terms of only the column water vapor amount and the solar zenith angle was tested against surface observations. Net surface fluxes deduced from coincidental collocated satellite-measured radiances and from measurements from towers in Boulder during summer and near Saskatoon in winter have mean differences of about 2 W/sq m, regardless of whether the sky is clear or cloudy. Furthermore, comparisons between the net fluxes deduced from the parameterization and from surface measurements showed equally good agreement when the data were partitioned into morning and afternoon observations. This is in contrast to results from an empirical clear-sky algorithm that is unable to account adequately for the effects of clouds and that shows, at Boulder, a distinct morning to afternoon variation. It is also demonstrated that the parameterization may be applied to irradiances at the top of the atmosphere that have been temporally averaged. The good agreement between the results of the parameterization and surface measurements suggests that the algorithm is a useful tool for a variety of climate studies.

  4. Absorbed doses and energy imparted from radiographic examination of velopharyngeal function during speech

    International Nuclear Information System (INIS)

    Isberg, A.; Julin, P.; Kraepelien, T.; Henrikson, C.O.

    1989-01-01

    Absorbed doses of radiation were measured by thermoluminescent dosimeters (TLDs) using a skull phantom during simulated cinefluorographic and videofluorographic examination of velopharyngeal function in frontal and lateral projections. Dosages to the thyroid gland, the parotid gland, the pituitary gland, and ocular lens were measured. Radiation dosage was found to be approximately 10 times less for videofluoroscopy when compared with that of cinefluoroscopy. In addition, precautionary measures were found to reduce further the exposure of radiation-sensitive tissues. Head fixation and shielding resulted in dose reduction for both video- and cinefluoroscopy. Pulsing exposure for cinefluoroscopy also reduced the dosage

  5. Electron-cyclotron heating in net using the ordinary mode at down-shifted frequency

    International Nuclear Information System (INIS)

    Fidone, I.; Giruzzi, G.

    1990-01-01

    A scenario for central heating in NET device is discussed using wave sources and wave launching from the most accessible side of the torus. The method presents two advantages: low wave frequency and side launch of the 0- mode. The maximum wave attenuation occurs for θ different to zero. It is a difficulty which is minimized by the fact that no special polarization is required for the reflected wave, since both modes are absorbed by the plasma core

  6. Study on the quality assurance of diagnostic X-ray machines and assessment of the absorbed dose to patients

    Science.gov (United States)

    Hassan, G. M.; Rabie, N.; Mustafa, K. A.; Abdel-Khalik, S. S.

    2012-09-01

    Radiation exposure and image quality in X-ray diagnostic radiology provide a clear understanding of the relationship between the radiation dose delivered to a patient and image quality in optimizing medical diagnostic radiology. Because a certain amount of radiation is unavoidably delivered to patients, this should be as low as reasonably achievable. Several X-ray diagnostic machines were used at different medical diagnostic centers in Egypt for studying the beam quality and the dose delivered to the patient. This article studies the factors affecting the beam quality, such as the kilo-volt peak (kVp), exposure time (mSc), tube current (mAs) and the absorbed dose in (μGy) for different examinations. The maximum absorbed dose measured per mAs was 594±239 and 12.5±3.7 μGy for the abdomen and the chest, respectively, while the absorbed dose at the elbow was 18±6 μGy, which was the minimum dose recorded. The compound and expanded uncertainties accompanying these measurements were 4±0.35% and 8±0.7%, respectively. The measurements were done through quality control tests as acceptance procedures.

  7. Discriminating electromagnetic radiation based on angle of incidence

    Science.gov (United States)

    Hamam, Rafif E.; Bermel, Peter; Celanovic, Ivan; Soljacic, Marin; Yeng, Adrian Y. X.; Ghebrebrhan, Michael; Joannopoulos, John D.

    2015-06-16

    The present invention provides systems, articles, and methods for discriminating electromagnetic radiation based upon the angle of incidence of the electromagnetic radiation. In some cases, the materials and systems described herein can be capable of inhibiting reflection of electromagnetic radiation (e.g., the materials and systems can be capable of transmitting and/or absorbing electromagnetic radiation) within a given range of angles of incidence at a first incident surface, while substantially reflecting electromagnetic radiation outside the range of angles of incidence at a second incident surface (which can be the same as or different from the first incident surface). A photonic material comprising a plurality of periodically occurring separate domains can be used, in some cases, to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation, based upon the angle of incidence. In some embodiments, one domain of the photonic material can include an isotropic dielectric function, while another domain of the photonic material can include an anisotropic dielectric function. In some instances, one domain of the photonic material can include an isotropic magnetic permeability, while another domain of the photonic material can include an anisotropic magnetic permeability. In some embodiments, non-photonic materials (e.g., materials with relatively large scale features) can be used to selectively absorb incoming electromagnetic radiation based on angle of incidence.

  8. Measurement and modelling of radiation transmission within a stand of maritime pine (Pinus pinaster Ait)

    International Nuclear Information System (INIS)

    Berbigier, P.; Bonnefond, J.M.

    1995-01-01

    A semi-empirical model of radiation penetration in a maritime pine canopy was developed so that mean solar (and net) radiation absorption by crowns and understorey could be estimated from above-canopy measurements only. Beam radiation Rb was assumed to penetrate the canopy according to Beer's law with an extinction coefficient of 0.32; this figure was found using non-linear regression techniques. For diffuse sky radiation, Beer's law was integrated over the sky vault assuming a SOC (standard overcast sky) luminance model; the upward and downward scattered radiative fluxes were obtained using the Kubelka-Munk equations and measurements of needle transmittance and reflectance. The penetration of net radiation within the canopy was also modelled. The model predicts the measured albedo of the stand very well. The estimation of solar radiation transmitted by the canopy was also satisfactory with the maximum difference between this and the mean output of mobile sensors at ground level being only 18 W m -2 . Due to the poor precision of net radiometers, the net radiation model could not be tested critically. However, as the modelled longwave radiation balance under the canopy is always between -10 and -20 Wm -2 , the below-canopy net radiation must be very close to the solar radiation balance. (author) [fr

  9. Fricke Xylenol Gel characterization at megavoltage radiation energy

    Energy Technology Data Exchange (ETDEWEB)

    Del Lama, Lucas Sacchini, E-mail: lucasdellama@gmail.com [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, n" o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil); Petchevist, Paulo César Dias [Oncoville, Centro de Excelência em Radioterapia em Curitiba, Rodovia BR-277, n" o 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil); Almeida, Adelaide de [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, n" o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil)

    2017-03-01

    Accurate determination of absorbed dose is of great importance in every medical application of ionizing radiation, mainly when involving biological tissues. Among different types of dosimeters, the ferrous sulfate chemical solution, known as Fricke solution, can be detached, due to its accuracy, reproducibility and linearity, been used in radiation dosimetry for over 50 years. Besides these characteristics, the Fricke Xylenol Gel (FXG), became one of the most known dosimeters for absorbed dose spatial distribution because of its high spatial resolution. In this work, we evaluated the FXG dosimeter taking into account different preparation recipes, in order to characterize its response in terms of absorbed dose range, linearity, sensitivity and fading.

  10. Fricke Xylenol Gel characterization at megavoltage radiation energy

    International Nuclear Information System (INIS)

    o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" data-affiliation=" (Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, no 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" >Del Lama, Lucas Sacchini; o 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil))" data-affiliation=" (Oncoville, Centro de Excelência em Radioterapia em Curitiba, Rodovia BR-277, no 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil))" >Petchevist, Paulo César Dias; o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" data-affiliation=" (Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, no 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" >Almeida, Adelaide de

    2017-01-01

    Accurate determination of absorbed dose is of great importance in every medical application of ionizing radiation, mainly when involving biological tissues. Among different types of dosimeters, the ferrous sulfate chemical solution, known as Fricke solution, can be detached, due to its accuracy, reproducibility and linearity, been used in radiation dosimetry for over 50 years. Besides these characteristics, the Fricke Xylenol Gel (FXG), became one of the most known dosimeters for absorbed dose spatial distribution because of its high spatial resolution. In this work, we evaluated the FXG dosimeter taking into account different preparation recipes, in order to characterize its response in terms of absorbed dose range, linearity, sensitivity and fading.

  11. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    International Nuclear Information System (INIS)

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-01-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure

  12. The Photostabilizing Effect of Grape Seed Extract on Three Common Sunscreen Absorbers.

    Science.gov (United States)

    Martincigh, Bice S; Ollengo, Moses A

    2016-11-01

    The photostabilizing ability of grape seed extract on three common sunscreen absorbers, 2-ethylhexyl-p-methoxycinnamate (EHMC), benzophenone-3 (BP3) and tert-butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC-MS and HPLC-MS, and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract. All sunscreens showed an improved photostability in the extract. The inherent photo-instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions, thereby improving the broad-spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad-spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented buildup of photoproducts whose toxicities are currently unknown. © 2016 The American Society of Photobiology.

  13. Light absorbing organic carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions

    Science.gov (United States)

    The light absorption of carbonaceous aerosols plays an important role in the atmospheric radiation balance. Light-absorbing organic carbon (OC), also called brown carbon (BrC), from laboratory-based biomass burning (BB) has been studied intensively to understand the contribution ...

  14. Net emission coefficient for CO–H2 thermal plasmas with the consideration of molecular systems

    International Nuclear Information System (INIS)

    Billoux, T.; Cressault, Y.; Gleizes, A.

    2015-01-01

    This paper deals with the calculation of net emission coefficients (NECs) for CO–H 2 thermal plasmas. This task required the elaboration of a complete spectroscopic database including atoms and molecules formed by carbon, oxygen and hydrogen elements. We have used a systematic line by line method to calculate all the main radiative contributions which are the atomic and molecular continua, the atomic lines and the molecular (diatomic and polyatomic) lines. The main diatomic electronic systems for CO–H 2 plasmas and the triatomic molecular bands were considered. We present some variations of the net emission coefficient versus temperature, for various pressures and for two relative proportions of the components. The role of the diatomic molecules is important at temperatures lower than 5000 K whereas the net emission coefficient presents an unusual peak at temperature around 1000 K, due to the presence of the CO 2 molecule presenting a strong infrared radiation. Finally, the results show that the NEC slightly depends on the relative proportion of CO and H 2 . - highlights: • We calculate radiative losses from CO–H 2 thermal plasmas. • We use the up-to-date atomic and molecular databases. • The influence of CO 2 molecule is very important at low temperature. • The relative maximum of the net emission coefficient at low temperature is unusual

  15. Direct solar steam generation inside evacuated tube absorber

    Directory of Open Access Journals (Sweden)

    Khaled M. Bataineh

    2016-12-01

    Full Text Available Direct steam generation by solar radiation falling on absorber tube is studied in this paper. A system of single pipe covered by glass material in which the subcooled undergoes heating and evaporation process is analyzed. Mathematical equations are derived based on energy, momentum and mass balances for system components. A Matlab code is built to simulate the flow of water inside the absorber tube and determine properties of water along the pipe. Widely accepted empirical correlations and mathematical models of turbulent flow, pressure drop for single and multiphase flow, and heat transfer are used in the simulation. The influences of major parameters on the system performance are investigated. The pressure profiles obtained by present numerical solution for each operation condition (3 and 10 MPa matches very well experimental data from the DISS system of Plataforma Solar de Almería. Furthermore, results obtained by simulation model for pressure profiles are closer to the experimental data than those predicted by already existed other numerical model.

  16. NET-2 Network Analysis Program

    International Nuclear Information System (INIS)

    Malmberg, A.F.

    1974-01-01

    The NET-2 Network Analysis Program is a general purpose digital computer program which solves the nonlinear time domain response and the linearized small signal frequency domain response of an arbitrary network of interconnected components. NET-2 is capable of handling a variety of components and has been applied to problems in several engineering fields, including electronic circuit design and analysis, missile flight simulation, control systems, heat flow, fluid flow, mechanical systems, structural dynamics, digital logic, communications network design, solid state device physics, fluidic systems, and nuclear vulnerability due to blast, thermal, gamma radiation, neutron damage, and EMP effects. Network components may be selected from a repertoire of built-in models or they may be constructed by the user through appropriate combinations of mathematical, empirical, and topological functions. Higher-level components may be defined by subnetworks composed of any combination of user-defined components and built-in models. The program provides a modeling capability to represent and intermix system components on many levels, e.g., from hole and electron spatial charge distributions in solid state devices through discrete and integrated electronic components to functional system blocks. NET-2 is capable of simultaneous computation in both the time and frequency domain, and has statistical and optimization capability. Network topology may be controlled as a function of the network solution. (U.S.)

  17. Determination of high level absorbed dose in a 60Co gamma ray field with ionization chambers

    International Nuclear Information System (INIS)

    Zhongying Li; Benjiang Mao; Lu Zhang

    1995-01-01

    This paper relates to the principles and methods for determining the absorbed dose of high energy photons radiation with ionization chambers, and its shows the doserate results of high level 60 Co γ-rays in water measured with Farmer chambers. The results with two kinds of chambers at a same point are consistent within 0.3%, and the total uncertainty is less than ± 4%. In the domestic intercomparison on determining high level absorbed dose in which 12 laboratories participated, the deviation of our result from the mean result of the intercomparison is -0.04% [Chen Yundong (1992). Summing up report on a high level absorbed dose intercomparison (in Chinese)]. (author)

  18. Cancer risks after radiation exposures

    International Nuclear Information System (INIS)

    Voelz, G.L.

    1980-01-01

    A general overview of the effects of ionizing radiation on cancer induction is presented. The relationship between the degree of risk and absorbed dose is examined. Mortality from radiation-induced cancer in the US is estimated and percentages attributable to various sources are given

  19. Pregnant woman mode for absorbed fraction calculations

    International Nuclear Information System (INIS)

    Cloutier, R.J.; Snyder, W.S.; Watson, E.E.

    1977-01-01

    The most radiation-sensitive segment of our population is the developing fetus. Until recently, methods available for calculating the dose to the fetus were inadequate because a model for the pregnant woman was not available. Instead, the Snyder and Fisher model of Reference Man, which includes a uterus, was frequently used to calculate absorbed fractions when the source was in various organs of the body and the nongravid uterus was the target. These values would be representative of the dose to the embryo during the early stages of pregnancy. Unfortunately, Reference Man is considerable larger than Reference Woman. The authors recently reported on the design of a Reference Woman phantom that has dimensions quite similar to the ICRP Reference Woman. This phantom was suitable for calculating the dose to the embryo during early stages of pregnancy (0 to 3 mo.), but was not suitable for the later stages of pregnancy because of the changing shape of the mother and the displacement of several abdominal organs brought about by the growth of the uterus and fetus. The models of Reference Woman that were subsequently developed for each month of pregnancy are described. The models take into account the growth of the uterus and fetus and the repositioning of the various abdominal organs. These models have been used to calculate absorbed fractions for the fetus as a target and the gastrointestinal tract as a source of radiation for twelve photon energies ranging from 10 keV to 4 MeV

  20. Effect of the bio-absorbent on the microwave absorption property of the flaky CIPs/rubber absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yang; Xu, Yonggang, E-mail: xuyonggang221@163.com; Cai, Jun; Yuan, Liming; Zhang, Deyuan

    2015-09-01

    Microwave absorbing composites filled with flaky carbonyl iron particles (CIPs) and the bio-absorbent were prepared by using a two-roll mixer and a vulcanizing machine. The electromagnetic (EM) parameters were measured by a vector network analyzer and the reflection loss (RL) was measured by the arch method in the frequency range of 1–4 GHz. The uniform dispersion of the absorbents was verified by comparing the calculated RL with the measured one. The results confirm that as the bio-absorbent was added, the permittivity was increased due to the volume content of absorbents, and the permeability was enlarged owing to the volume content of CIPs and interactions between the two absorbents. The composite filled with bio-absorbents achieved an excellent absorption property at a thickness of 1 mm (minimum RL reaches −7.8 dB), and as the RL was less than −10 dB the absorption band was widest (2.1–3.8 GHz) at a thickness of 2 mm. Therefore, the bio-absorbent is a promising additive candidate on fabricating microwave absorbing composites with a thinner thickness and wider absorption band. - Graphical abstract: Morphology of composites filled with flaky CIPs and the bio-absorbent. The enhancement of bio-absorbent on the electromagnetic absorption property of composites filled with flaky carbonyl iron particles (CIPs) is attributed to the interaction of the two absorbents. The volume content of the FCMPs with the larger shape CIPs play an important role in this effects, the composites filled with irons and bio-absorbents can achieve wider-band and thinner-thickness absorbing materials. - Highlights: • Absorbers filled with bio-absorbents and CIPs was fabricated. • Bio-absorbents enhanced the permittivity and permeability of the composites. • The absorbent interactions play a key role in the enhancement mechanism. • Bio-absorbents enhanced the composite RL in 1–4 GHz.

  1. Contribution of magnetic measurements onboard NetLander to Mars exploration

    DEFF Research Database (Denmark)

    Menvielle, M.; Musmann, G.; Kuhnke, F.

    2000-01-01

    between the environment of the planet and solar radiation, and a secondary source, the electric currents induced in the conductive planet. The continuous recording of the time variations of the magnetic field at the surface of Mars by means of three component magnetometers installed onboard Net...

  2. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  3. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  4. A dynamic simulation to study NET in-vessel handling operations

    International Nuclear Information System (INIS)

    Fung, P.T.F.

    1989-01-01

    The inspection, maintenance and repair of the Next European Torus (NET) fusion machine will require the extensive use of remote handling equipment to minimise the human exposure to the high radiation environment. The use of efficient manipulators will reduce the NET downtime by reducing the preparation time for entry into the controlled area and by performing the task with reasonable area and by performing the task with reasonable dexterity and speed, consistent with safety. A high fidelity simulation is a valuable tool to assist in the manipulator design, operations, trajectory planning, parameter optimisation and system verification. A manipulator simulation package called ASAD was originally developed by Spar for space manipulator applications. It is now being adapted to simulate the in-Vessel HandlingUnit for the NET program. This terestrial version of ASAD has been name ASAD - T. Spar, through the services of the Canadian Fusion Fuels Technology Project, is under contract to the NET program for the performance of this activity. This paper describes the capabillities and underlying assumptions of ASAD - T, aling with description of the simulation development of the NET in-vessel manipulator. (author). 4 refs.; 7 figs

  5. Winter radiation extinction and reflection in a boreal pine canopy: measurements and modelling

    International Nuclear Information System (INIS)

    Pomeroy, J.W.; Dion, K.

    1996-01-01

    Predicting the rate of snow melt and intercepted snow sublimation in boreal forests requires an understanding of the effects of snow-covered conifers on the exchange of radiant energy. This study examined the amount of intercepted snow on a jack pine canopy in the boreal forest of central Saskatchewan and the shortwave and net radiation exchange with this canopy, to determine the effect of intercepted snow and canopy structure on shortwave radiation reflection and extinction and net radiation attenuation in a boreal forest. The study focused on clear sky conditions, which are common during winter in the continental boreal forest. Intercepted snow was found to have no influence on the clear-sky albedo of the canopy, the extinction of short wave radiation by the canopy or ratio of net radiation at the canopy top to that at the surface snow cover. Because of the low albedo of the snow-covered canopy, net radiation at the canopy top remains positive and a large potential source of energy for sublimation. The canopy albedo declines somewhat as the extinction efficiency of the underlying canopy increases. The extinction efficiency of short wave radiation in the canopy depends on solar angle because of the approximately horizontal orientation of pine branches. For low solar angles above the horizon, the extinction efficiency is quite low and short wave transmissivity through the canopy is relatively high. As the solar angle increases, extinction increases up to angles of about 50°, and then declines. Extinction of short wave radiation in the canopy strongly influences the attenuation of net radiation by the canopy. Short wave radiation that is extinguished by branches is radiated as long wave, partly downwards to the snow cover. The ratio of net radiation at the canopy top to that at the snow cover surface increases with the extinction of short wave radiation and is negative for low extinction efficiencies. For the pine canopy examined, the daily mean net radiation at

  6. Assessment of human effective absorbed dose of 67 Ga-ECC based on biodistribution rat data.

    Science.gov (United States)

    Shanehsazzadeh, Saeed; Yousefnia, Hassan; Lahooti, Afsaneh; Zolghadri, Samaneh; Jalilian, Amir Reza; Afarideh, Hossien

    2015-02-01

    In a diagnostic context, determination of absorbed dose is required before the introduction of a new radiopharmaceutical to the market to obtain marketing authorization from the relevant agencies. In this work, the absorbed dose of [67 Ga]-ethylenecysteamine cysteine [(67 Ga)ECC] to human organs was determined by using distribution data for rats. For biodistribution data, the animals were sacrificed by CO2 asphyxiation at selected times after injection (0.5, 2 and 48 h, n = 3 for each time interval), then the tissue (blood, heart, lung, brain, intestine, feces, skin, stomach, kidneys, liver, muscle and bone) were removed. The absorbed dose was determined by Medical Internal Radiation Dose (MIRD) method after calculating cumulated activities in each organ. Our prediction shows that a 185-MBq injection of (67)Ga-ECC into the humans might result in an estimated absorbed dose of 0.029 mGy in the whole body. The highest absorbed doses are observed in the spleen and liver with 33.766 and 16.847 mGy, respectively. The results show that this radiopharmaceutical can be a good SPECT tracer since it can be produced easily and also the absorbed dose in each organ is less than permitted absorbed dose.

  7. Synchrotron radiation facilities

    CERN Multimedia

    1972-01-01

    Particularly in the past few years, interest in using the synchrotron radiation emanating from high energy, circular electron machines has grown considerably. In our February issue we included an article on the synchrotron radiation facility at Frascati. This month we are spreading the net wider — saying something about the properties of the radiation, listing the centres where synchrotron radiation facilities exist, adding a brief description of three of them and mentioning areas of physics in which the facilities are used.

  8. Our khowledge of radiation?

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Exposure pathways of natural source radiation on man are shown. Radiation earth sources give on an average more, than 5/6 of the year effective equivalent dose absorbed by population mainly due to the internal radiation. Radon and its decay products which are contained in many building materials and in water and natural gas as well, require particular attention. Necessity to carry out radiation control of building materias, as well as, other measures dealing with reduction of radon concentration in houses is underlined

  9. Net-baryon-, net-proton-, and net-charge kurtosis in heavy-ion collisions within a relativistic transport approach

    International Nuclear Information System (INIS)

    Nahrgang, Marlene; Schuster, Tim; Stock, Reinhard; Mitrovski, Michael; Bleicher, Marcus

    2012-01-01

    We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand-canonical ensemble we explicitly take into account exact electric and baryon charge conservation on an event-by-event basis. This drastically limits the width of baryon fluctuations. A simple model to account for this is to assume a grand-canonical distribution with a sharp cut-off at the tails. We present baseline predictions of the energy dependence of the net-baryon, net-proton and net-charge kurtosis for central (b≤2.75 fm) Pb+Pb/Au+Au collisions from E lab =2A GeV to √(s NN )=200 GeV from the UrQMD model. While the net-charge kurtosis is compatible with values around zero, the net-baryon number decreases to large negative values with decreasing beam energy. The net-proton kurtosis becomes only slightly negative for low √(s NN ). (orig.)

  10. Long-term effects of elevated ozone and UV-B radiation on vegetation and methane dynamics in northern peatland ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Morsky, S.K.

    2012-06-15

    In the stratosphere, ozone (O{sub 3}) forms an effective barrier against high energy ultraviolet radiation (UV), which is harmful to living cells. Despite the stratospheric O{sub 3} layer recovering due to international agreements, seasonal O{sub 3} depletion periods with high UV-B levels, may still occur, especially in the Polar regions. In the troposphere, O{sub 3} is a significant greenhouse gas contributing to global warming and also causing oxidative stress to animal- and plant cells. Global tropospheric O{sub 3} concentration has approximately doubled during the last century and the same trend is expected to continue. Northern peatlands are sinks of atmospheric carbon dioxide (CO{sub 2}) and sources of the powerful greenhouse gas methane (CH{sub 4}). Two multi-year open-field experiments were conducted to study the effects of elevated O{sub 3} concentration and UV-B radiation on peatland vegetation and CH{sub 4} dynamics in Finland. Peatland microcosms were used in the O{sub 3} experiment and the UV-B exposure study was conducted on a natural fen. Elevated O{sub 3} concentration significantly increased leaf cross-sections and the total number of Eriophorum vaginatum leaves towards the end of the experiment, but did not affect relative length growth, stomatal density or volume of aerenchymatous tissue of leaves. Elevated O{sub 3} did not affect relative length growth of Sphagnum papillosum shoots either. Concentrations of chlorophylls or carotenoids in E. vaginatum leaves or in S. papillosum shoots were not changed under elevated O{sub 3}. During the first growing season, elevated O{sub 3} concentration decreased methanol-extractable, UV-absorbing compounds in E. vaginatum leaves. Elevated O{sub 3} increased concentrations of organic acids and microbial biomass (estimated by phospholipid fatty acid biomarkers) in peat during the third growing season. In the first growing season net CH{sub 4} emission was temporarily decreased by elevated O{sub 3} concentration

  11. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P; Koskela, T; Damski, J; Supperi, A [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1997-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  12. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  13. Absorbant materials

    International Nuclear Information System (INIS)

    Quetier, Monique.

    1978-11-01

    Absorbants play a very important part in the nuclear industry. They serve for the control, shut-down and neutron shielding of reactors and increase the capacity of spent fuel storage pools and of special transport containers. This paper surveys the usual absorbant materials, means of obtainment, their essential characteristics relating to their use and their behaviour under neutron irradiation [fr

  14. Estimation of absorbed doses in humans due to intravenous administration of fluorine-18-fluorodeoxyglucose in PET studies

    International Nuclear Information System (INIS)

    Mejia, A.A.; Nakamura, T.; Masatoshi, I.; Hatazawa, J.; Masaki, M.; Watanuki, S.

    1991-01-01

    Radiation absorbed doses due to intravenous administration of fluorine-18-fluorodeoxyglucose in positron emission tomography (PET) studies were estimated in normal volunteers. The time-activity curves were obtained for seven human organs (brain, heart, kidney, liver, lung, pancreas, and spleen) by using dynamic PET scans and for bladder content by using a single detector. These time-activity curves were used for the calculation of the cumulative activity in these organs. Absorbed doses were calculated by the MIRD method using the absorbed dose per unit of cumulated activity, 'S' value, transformed for the Japanese physique and the organ masses of the Japanese reference man. The bladder wall and the heart were the organs receiving higher doses of 1.2 x 10(-1) and 4.5 x 10(-2) mGy/MBq, respectively. The brain received a dose of 2.9 x 10(-2) mGy/MBq, and other organs received doses between 1.0 x 10(-2) and 3.0 x 10(-2) mGy/MBq. The effective dose equivalent was estimated to be 2.4 x 10(-2) mSv/MBq. These results were comparable to values of absorbed doses reported by other authors on the radiation dosimetry of this radiopharmaceutical

  15. Development of optical tools for the characterization of selective solar absorber at elevated temperature

    Science.gov (United States)

    Giraud, Philemon; Braillon, Julien; Delord, Christine; Raccurt, Olivier

    2016-05-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The objective is to develop new optical equipment for characterization of this solar absorber in condition of use that is to say in air and at elevated temperature. In this paper we present two new optical test benches developed for optical characterization of solar absorbers in condition of use up to 800°C. The first equipment is an integrated sphere with heated sample holder which measures the hemispherical reflectance between 280 and 2500 nm to calculate the solar absorbance at high temperature. The second optical test bench measures the emittance of samples up to 1000°C in the range of 1.25 to 28.57 µm. Results of high temperature measurements on a series of metallic absorbers with selective coating and refractory material for high thermal receiver are presented.

  16. Eye lens dosimetry for interventional procedures – Relation between the absorbed dose to the lens and dose at measurement positions

    International Nuclear Information System (INIS)

    Geber, Therese; Gunnarsson, Mikael; Mattsson, Sören

    2011-01-01

    This study investigated the relationship between the absorbed dose to the lens of the eye and the absorbed dose at different measurement positions near the eye of interventional radiologists. It also visualised the dose distribution inside the head, both when protective eyewear were used and without such protection. The best position for an eye lens dosimeter was found to be at the side of the head nearest to the radiation source, close to the eye. Positioning the dosimeter at the eyebrow could lead to an underestimation of the lens dose of as much as 45%. The measured dose distribution showed that the absorbed dose to the eye lenses was high compared to the other parts of the head, which stresses the importance of wearing protective eyewear. However, many models of eyewear were found to be deficient as the radiation could slip through at several places, e.g. at the cheek. The relationship between the absorbed dose to the lens and the kerma-area-product (P KA ) delivered to the patient was also studied.

  17. NSC KIPT's experience in production of absorber materials, composites and products for control mechanisms of various nuclear reactor types

    International Nuclear Information System (INIS)

    Odeychuk, N.P.; Zelensky, V.F.; Gurin, V.A.; Konotop, Yu.F.

    2000-01-01

    Data on NSC KIPT developments of absorber composites B 4 C-PyC and B 4 C-SiC are reported. Results of pre-reactor studies and reactor tests of absorber composites developed are given. It is shown that the B 4 C-PyC composites have a high radiation resistance at temperatures up to 1,250 deg C. (author)

  18. Neutron, Proton, and Photonuclear Cross Sections for Radiation Therapy and Radiation Protection

    International Nuclear Information System (INIS)

    Chadwick, M.B.

    1998-01-01

    The authors review recent work at Los Alamos to evaluate neutron, proton, and photonuclear cross section up to 150 MeV (to 250 MeV for protons), based on experimental data and nuclear model calculations. These data are represented in the ENDF format and can be used in computer codes to simulate radiation transport. They permit calculations of absorbed dose in the body from therapy beams, and through use of kerma coefficients allow absorbed dose to be estimated for a given neutron energy distribution. For radiation protection, these data can be used to determine shielding requirements in accelerator environments, and to calculate neutron, proton, gamma-ray, and radionuclide production. Illustrative comparisons of the evaluated cross section and kerma coefficient data with measurements are given

  19. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

    2012-05-10

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

  20. Radiation protection

    International Nuclear Information System (INIS)

    Kamalaksh Shenoy, K.

    2013-01-01

    Three main pillars underpin the IAEA's mission: Safety and Security - The IAEA helps countries to upgrade their infrastructure for nuclear and radiation safety and security, and to prepare for and respond to emergencies. Work is keyed to international conventions, the development of international standards and the application of these standards. The aim is to protect people and the environment from the harmful effects of exposure to ionizing radiation. Science and Technology - The IAEA is the world's focal point for mobilizing peaceful applications of nuclear science and technology for critical needs in developing countries. The work contributes to alleviating poverty, combating disease and pollution of the environment and to other goals of sustainable development. Safeguards and Verification - The IAEA is the nuclear inspectorate, with more than four decades of verification experience. Inspectors work to verify that nuclear material and activities are not diverted towards military purposes. Quantities and Units: Dose equivalent is the product of absorbed dose of radiation and quality factor (Q). For absorbed dose in rads, dose equivalent is in rems. If absorbed dose is in gray, the dose equivalent is in sievert. Quality factor is defined without reference to any particular biological end point. Quality factors are recommended by committees such as the International Commission on Radiological Protection (ICRP) or the National Council on Radiation Protection and Measurements (NCRP), based on experimental RBE values but with some judgment exercised. Effective Dose Equivalent: It is the sum of the weighted dose equivalents for all irradiated tissues, in which the weighting factors represent the different risks of each tissue to mortality from cancer and hereditary effects. Committed dose equivalent: It is the integral over 50 years of dose equivalent following the intake of a radionuclide. Collective effective dose equivalent: It is a quantity for a population and is

  1. Ionizing radiation in the field of hydrogels used for agriculture and medicine

    International Nuclear Information System (INIS)

    Radoiu, M.; Martin, D.; Oproiu, C.; Indreias, I; Toma, M.; Dragusin, M.; Moraru, R.; Manea, A.

    1998-01-01

    The hydrogels, such as homopolymers of acrylamide (AHH type), co-polymers of acrylamide-sodium acrylate (ANACH type) and homopolymers of sodium acrylate (NAHH type), obtained by gamma ray and accelerated electron beam are presented. The effects of the solution chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of these hydrogel types are discussed. Distilled water, physiological serum and 4 N NaCl aqueous solution were used as swelling medium. Radiation absorbed dose has an important effect upon the swelling degree of AHH and ANACH types especially when distilled water is used as swelling medium while the NAHH swelling degree presents a small dependence versus absorbed dose for all swelling medium types. Usually, the swelling degree for all hydrogel types decreases versus absorbed dose and absorbed dose rate and exhibits the higher values for distilled water as swelling medium. The hydrogels mechanical strength exhibits a maximum value versus absorbed dose. The best values for mechanical strength depend on hydrogel type and swelling medium. The used range for absorbed dose was from 2 kGy to 16 kGy. Our types of hydrogels were developed for some applications such as in agriculture (AHH and ANACH types) to maintain soil humidity and in medicine as absorption material for dressing (NAHH types). (author)

  2. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Staaij, J.W.M. van de; Ernst, W. H.O.; Hakvoort, H. W.J.; Rozema, J. [Vrije Univ., Amsterdam (Netherlands)

    1995-07-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  3. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    International Nuclear Information System (INIS)

    Staaij, J.W.M. van de; Ernst, W.H.O.; Hakvoort, H.W.J.; Rozema, J.

    1995-01-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  4. Proceedings of the workshop 'Absorbed dose in water and air'

    International Nuclear Information System (INIS)

    Rapp, Benjamin; Bordy, Jean-Marc; Camacho Caldeira, Margarida Isabela; Sochor, Vladimir; Celarel, Aurelia; Cenusa, Constentin; Cenusa, Ioan; Donois, Marc; Dusciac, Dorin; Iliescu, Elena; Ostrowsky, Aime; Bercea, Sorin; Blideanu, Valentin; Bordy, Jean-Marc; Steurer, Andrea; Tiefenboeck, Wilhelm

    2017-05-01

    The project 'Absorbed dose in water and air' (Absorb) is aimed at sharing and improving the knowledge on the design of Primary Standards (calorimeter, cavity ionization chambers, free air ionization chambers) for 'dose' measurements in radiation therapy and diagnostic, the harmonization of calibration procedures, the determination of uncertainty and harmonization of uncertainty budgets. Within the framework of this project a workshop was organized at the LNE (Laboratoire National de metrologie et d'Essais) in Paris from February, 29 to March, 2 2016. This report is the proceeding of this workshop. It includes a state of the art of two bilateral collaborations, launched to go beyond the framework of Absorb, between CEA LIST (LNE) LNHB and in one hand IFIN-HH (Romania), and in the other hand IST-LPSR-LMRI (Portugal) to build primary cavity ionization chambers for photons emitted by cobalt-60 and Cesium-137. Absorb is a Joint Research Project of the European Metrology Programme for Innovation and Research (EMPIR) which is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States

  5. A new approach to implement absorbing boundary condition in biomolecular electrostatics.

    Science.gov (United States)

    Goni, Md Osman

    2013-01-01

    This paper discusses a novel approach to employ the absorbing boundary condition in conjunction with the finite-element method (FEM) in biomolecular electrostatics. The introduction of Bayliss-Turkel absorbing boundary operators in electromagnetic scattering problem has been incorporated by few researchers. However, in the area of biomolecular electrostatics, this boundary condition has not been investigated yet. The objective of this paper is twofold. First, to solve nonlinear Poisson-Boltzmann equation using Newton's method and second, to find an efficient and acceptable solution with minimum number of unknowns. In this work, a Galerkin finite-element formulation is used along with a Bayliss-Turkel absorbing boundary operator that explicitly accounts for the open field problem by mapping the Sommerfeld radiation condition from the far field to near field. While the Bayliss-Turkel condition works well when the artificial boundary is far from the scatterer, an acceptable tolerance of error can be achieved with the second order operator. Numerical results on test case with simple sphere show that the treatment is able to reach the same level of accuracy achieved by the analytical method while using a lower grid density. Bayliss-Turkel absorbing boundary condition (BTABC) combined with the FEM converges to the exact solution of scattering problems to within discretization error.

  6. Measurement of extrapolation curves for the secondary pattern of beta radiation Nr. 86 calibrated in rapidity of absorbed dose for tissue equivalent by the Physikalisch Technische Bundesanstalt

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1988-10-01

    The following report has as objective to present the obtained results of measuring - with a camera of extrapolation of variable electrodes (CE) - the dose speed absorbed in equivalent fabric given by the group of sources of the secondary pattern of radiation Beta Nr. 86, (PSB), and to compare this results with those presented by the calibration certificates that accompany the PSB extended by the primary laboratory Physikalisch Technische Bundesanstalt, (PTB), of the R.F.A. as well as the uncertainties associated to the measure process. (Author)

  7. The environmental radiation monitoring system and in-situ measurements for early notification and OIL (Operational Intervention Levels) calculations

    Energy Technology Data Exchange (ETDEWEB)

    Haquin, G.; Ne`eman, E.; Brenner, S.; Lavi, N. [Tel Aviv Univ. (Israel). Sackler School of Medicine. Inst. for Environmental Research

    1997-12-31

    The efficiency of the environmental radiation monitoring, low level laboratory and in-situ gamma-ray spectrometry are evaluated as the systems for early notification and for determination of dose rate in air, surface contamination and activity concentration in food during emergencies for Operational Intervention Levels (OIL) recalculation.The National Environmental Radiation Monitoring System has proved its efficiency in the early detection of unregistered radiography work. A mobile station of the network can be used for absorbed dose rate measurement during emergencies in contaminated areas. The calibrated in-situ gamma-ray spectrometry system in an open phosphate ore mine has showed the efficiency of this technique for fast and accurate determination of soil activity concentration. The calibration for an uniform depth distribution can be easily mathematically converted to an exponential depth distribution in cases of radioactive material fallout 7 refs., 3 figs., 1 tab.; e-mail: envirad at post.tau.ac.il; env{sub r}ad at netvision,net.il

  8. Magnitudes and units in radiation protection

    International Nuclear Information System (INIS)

    2005-01-01

    This sheet provides definition and information on the ionizing radiations, the measurement of a ionizing radiation magnitude by a radioactive source (the becquerel), the measurement of the ionizing radiation energy absorbed by the organism (the gray), the biological impact evaluation of ionizing radiations in function of their nature (the sievert) and the evaluation and comparison of biological risks bond to little doses (dose efficiency). (A.L.B.)

  9. Bayesian Methods for Radiation Detection and Dosimetry

    CERN Document Server

    Groer, Peter G

    2002-01-01

    We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed comp...

  10. Absorbed doses for patients undergoing panoramic radiography, cephalometric radiography and CBCT

    Directory of Open Access Journals (Sweden)

    Małgorzata Wrzesień

    2017-10-01

    Full Text Available Objectives: Contemporary dental radiology offers a wide spectrum of imaging methods but it also contributes to an increase in the participation of dental radiological diagnosis in the patient’s exposure to ionizing radiation. The aim of this study is to determine the absorbed doses of the brain, spinal column, thyroid and eye lens for patients during panoramic radiography, cephalometric radiography and cone beam computed tomography (CBCT. Material and Methods: The thermoluminescent dosimetry and anthropomorphic phantom was used for measuring the doses. The 15 panoramic, 4 cephalometric and 4 CBCT exposures were performed by placing high-sensitivity thermoluminescent detectors (TLD in 18 anatomical points of the phantom. Results: The maximum absorbed dose recorded during performed measurements corresponds to the point representing the brainstem and it is 10 mGy. The dose value recorded by the TLD placed in the thyroid during CBCT imaging in relation to the panoramic radiography differs by a factor of 13.5. Conclusions: Cone beam computed tomography, in comparison with panoramic or cephalometric imaging technique, provides higher radiation doses to the patients. Int J Occup Med Environ Health 2017;30(5:705–713

  11. Seasonal changes in the radiation balance of subarctic forest and tundra

    International Nuclear Information System (INIS)

    Lafleur, P.M.; Renzetti, A.V.; Bello, R.

    1993-01-01

    This paper examines the seasonal behavior of the components of the radiation budget of subarctic tundra and open forest near Churchill, Manitoba. Data were collected between late February and August 1990. The presence of the winter snowpack is the most important factor which affects the difference in radiation balances of tundra and forest. Overall, net radiation was about four to five times larger over the forest when snow covered the ground. Albedo differences were primarily responsible for this difference in net radiation; however, somewhat smaller net longwave losses were experienced at the tundra site. The step decrease in albedo from winter to summer (i.e. snow-covered to snow-free conditions) was significant at both sites. The forest albedo decreased by about three-fold while the tundra experienced a seven-fold decrease. Net radiation at both sites increased in direct response to the albedo change. Transmissivity of the atmosphere near Churchill also appeared to change at about the same time as the loss of the snow cover and may be related to changing air masses which bring about the final snow melt

  12. Calorimeter with capacitance transducer for measurement of SHF radiation power

    International Nuclear Information System (INIS)

    Kiselev, V.A.; Linnik, A.F.; Onishchenko, I.N.; Uskov, V.V.

    2005-01-01

    A calorimeter of simple design for measuring total energy of microwave radiation is described. It operates in the energy range of 0.5 J to 6 kJ; water is used as the absorbing material. A capacitive probe is applied to measure changes in the water volume. The energy absorption factor of electromagnetic radiation in the range of 3-60 GHz is at least 0.9. The calorimeter is insensitive to radiation field nonuniformity over the absorber volume. The calorimeter is intended for measuring the radiation energy of beam plasma generators and generators with dielectric structure. Its design makes it possible to simultaneously measure the radiation energy and monitor the beam current [ru

  13. Electron paramagnetic resonance measurements of absorbed dose in teeth from citizens of Ozyorsk

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, A.; Semiochkina, N. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany); Vasilenko, E.; Aladova, E.; Smetanin, M. [Southern Urals Biophysics Institute, Ozyorsk (Russian Federation); Fattibene, P. [Istituto Superiore di Sanita, Rome (Italy)

    2014-05-15

    In 1945, within the frame of the Uranium Project for the production of nuclear weapons, the Mayak nuclear facilities were constructed at the Lake Irtyash in the Southern Urals, Russia. The nuclear workers of the Mayak Production Association (MPA), who lived in the city of Ozyorsk, are the focus of epidemiological studies for the assessment of health risks due to protracted exposure to ionising radiation. Electron paramagnetic resonance measurements of absorbed dose in tooth enamel have already been used in the past, in an effort to validate occupational external doses that were evaluated in the Mayak Worker Dosimetry System. In the present study, 229 teeth of Ozyorsk citizens not employed at MPA were investigated for the assessment of external background exposure in Ozyorsk. The annually absorbed dose in tooth enamel from natural background radiation was estimated to be (0.7 ± 0.3) mGy. For citizens living in Ozyorsk during the time of routine noble gas releases of the MPA, which peaked in 1953, the average excess absorbed dose in enamel above natural background was (36 ± 29) mGy, which is consistent with the gamma dose obtained by model calculations. In addition, there were indications of possible accidental gaseous MPA releases that affected the population of Ozyorsk, during the early and late MPA operation periods, before 1951 and after 1960. (orig.)

  14. UV sensitivity of planktonic net community production in ocean surface waters

    OpenAIRE

    Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-01-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

  15. Petri Nets

    Indian Academy of Sciences (India)

    In a computer system, for example, typical discrete events ... This project brought out a series of influential reports on Petri net theory in the mid and late ... Technology became a leading centre for Petri net research and from then on, Petri nets ...

  16. Surface Net Solar Radiation Estimated from Satellite Measurements: Comparisons with Tower Observations

    Science.gov (United States)

    Li, Zhanqing; Leighton, H. G.; Cess, Robert D.

    1993-01-01

    A parameterization that relates the reflected solar flux at the top of the atmosphere to the net solar flux at the surface in terms of only the column water vapor amount and the solar zenith angle was tested against surface observations. Net surface fluxes deduced from coincidental collocated satellite-measured radiances and from measurements from towers in Boulder during summer and near Saskatoon in winter have mean differences of about 2 W/sq m, regardless of whether the sky is clear or cloudy. Furthermore, comparisons between the net fluxes deduced from the parameterization and from surface measurements showed equally good agreement when the data were partitioned into morning and afternoon observations. This is in contrast to results from an empirical clear-sky algorithm that is unable to account adequately for the effects of clouds and that shows, at Boulder, a distinct morning to afternoon variation, which is presumably due to the predominance of different cloud types throughout the day. It is also demonstrated that the parameterization may be applied to irradiances at the top of the atmosphere that have been temporally averaged by using the temporally averaged column water vapor amount and the temporally averaged cosine of the solar zenith angle. The good agreement between the results of the parameterization and surface measurements suggests that the algorithm is a useful tool for a variety of climate studies.

  17. Dyed grafted films for large-dose radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Abdel Rehim, F; El-Sawy, N M; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Cairo (Egypt)

    1993-07-01

    By radiation-induced polymerization of acrylic acid onto poly(ethylene-tetrafluoroethylene) (ET) copolymer film and reacting the resulted grafted film with both Rhodamine B (RB) and Malachite Green (MG), new dosimeter films have been developed for high-dose gamma radiation applications in the range of absorbed doses from 10 to 180 kGy. The radiation-induced color bleaching has been analysed with visible spectrophotometry, either at the maximum of the absorption band peaking at 559 nm (for ETRB) or that peaking at 627 nm (for ETMG). The effects of different conditions of absorbed dose rate, temperature and relative humidity during irradiation and post-irradiation storage on dosimeter performance are discussed. (author).

  18. Using RADFET for the real-time measurement of gamma radiation dose rate

    Science.gov (United States)

    Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

    2015-02-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h-1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

  19. Using RADFET for the real-time measurement of gamma radiation dose rate

    International Nuclear Information System (INIS)

    Andjelković, Marko S; Ristić, Goran S; Jakšić, Aleksandar B

    2015-01-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h −1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose. (paper)

  20. Aspects of the quality of data from the Southern Great Plains (SGP) cloud and radiation testbed (CART) site broadband radiation sensors

    Energy Technology Data Exchange (ETDEWEB)

    Splitt, M.E. [Univ. of Oklahoma, Norman, OK (United States); Wesely, M.L. [Argonne National Lab., IL (United States)

    1996-04-01

    A systmatic evaluation of the performance of broadband radiometers at the Radiation Testbed (CART) site is needed to estimate the uncertainties of the irradiance observations. Here, net radiation observed with the net radiometer in the enrgy balance Bowen ratio station at the Central facility is compared with the net radiation computed as the sum of component irradiances recorded by nearby pyranameters and pyrgeometers. In addition, data obtained from the central facility pyranometers, pyrgeometers, and pyrheliometers are examined for April 1994, when intensive operations periods were being carried out. The data used in this study are from central facility radiometers in a solar and infrared observation station, and EBBR station, the so-called `BSRN` set of upward pointing radiometers, and a set of radiometers pointed down at the 25-m level of a 60-m tower.

  1. Studies of the sensitivity dependence of float zone silicon diodes on gamma absorbed dose

    International Nuclear Information System (INIS)

    Pascoalino, K.C.S.; Santos, T.C. dos; Barbosa, R.F.; Camargo, F. de; Goncalves, J.A.C.; Bueno, C.C.

    2011-01-01

    Full text: Several advantages of silicon diodes which include small size, low cost, high sensitivity and wide availability, make them suitable for dosimetry and for radiation field mapping. However, the small radiation tolerance of ordinary silicon devices has imposed constraints on their application in intense radiation fields such as found in industrial radiation processes. This scenario has been changed with the development of radiation hard silicon devices to be used as track detectors in high-energy physics experiments. Particularly, in this work it is presented the dosimetric results obtained with a batch of nine junction silicon diodes developed, in the framework of CERN RD50 Collaboration, as good candidates for improved radiation hardness. These diodes were produced with 300 micrometer n-type silicon substrate grown by standard float zone technique and processed by the Microelectronics Center of Helsinki University of Technology. The samples irradiation was performed using a Co-60 irradiator (Gammacell 220) which delivers a dose-rate of 2 kGy/h. During the irradiation, the unbiased diodes were connected through low-noise coaxial cables to the input of a KEITHLEY 617 electrometer, in order to monitor the devices photocurrent as a function of the exposure time. To study the response uniformity of the batch of nine diodes as well the sensitivity dependence on the absorbed dose, they were irradiated with different doses from 5 kGy up to 50 kGy. The sensitivity response of each device was investigated through the on-line measurements of the current signals as a function of the exposure time. For doses up to 5 kGy, all diodes exhibited a current decay of almost six percent in comparison with the value registered at the start-time of the irradiation. However, this decrease in the current sensitivity is much smaller than those observed with ordinary diodes for the same absorbed dose. The dose-response curves of the devices were also investigated through the plot

  2. Accumulation of radiation defects and products of radiolysis in lithium orthosilicate pebbles with silicon dioxide additions under action of high absorbed doses and high temperature in air and inert atmosphere

    Science.gov (United States)

    Zarins, A.; Supe, A.; Kizane, G.; Knitter, R.; Baumane, L.

    2012-10-01

    One of the technological problems of a fusion reactor is the change in composition and structure of ceramic breeders (Li4SiO4 or Li2TiO3 pebbles) during long-term operation. In this study changes in the composition and microstructure of Li4SiO4 pebbles with 2.5 wt% silicon dioxide additions, fabricated by a melt-spraying process, were investigated after fast electron irradiation (E = 5 MeV, dose rate up to 88 MGy h-1) with high absorbed dose from 1.3 to 10.6 GGy at high temperature (543-573 K) in air and argon atmosphere. Three types of pebbles with different diameters and grain sizes were investigated. Products of radiolysis were studied by means of FTIR and XRD. TSL and ESR spectroscopy were used to detect radiation defects. SEM was used to investigate structure of pebbles. Experiments showed that Li4SiO4 pebbles with a diameter of 500 μm had similar radiation stability as pebbles with diameter <50 μm which were annealed at 1173 K for 128 h in argon and air atmosphere. As well as determined that lithium orthosilicate pebbles with size 500 (1243 K 168 h) and <50 μm (1173 K 128 h) have a higher radiation stability in air and argon atmosphere than pebbles with size <50 μm (1073 K 1 h). Degree of decomposition α10.56 of the lithium orthosilicate pebbles at an absorbed dose of 10.56 GGy in air atmosphere is 1.5% and 0.15% at irradiation in dry argon. It has been suggested that changes of radiation stability of lithium orthosilicate pebbles in air atmosphere comparing with irradiated pebbles in argon atmosphere is effect of chemical reaction of lithium orthosilicate surface with air containing - H2O and CO2 in irradiation process. As well as it has been suggested that silicon dioxide - lithium metasilicate admixtures do not affect formation mechanism of radiation defect and products of radiolysis in lithium orthosilicate pebbles.

  3. Enhancement of photosynthesis in Sorghum bicolor by ultraviolet radiation

    International Nuclear Information System (INIS)

    Johnson, G.A.; Day, T.A.

    2002-01-01

    We assessed the influence of ultraviolet radiation (UV) on net photosynthetic CO 2 assimilation rate (Pn) in Sorghum bicolor, with particular attention to examining whether UV can enhance Pn via direct absorption of UV and absorption of UV-induced blue fluorescence by photosynthetic pigments. A polychromatic UV response spectrum of leaves was constructed by measuring Pn under different UV supplements using filters that had sharp transmission cut-offs from 280 to 382 nm, against a background of non-saturating visible light. When the abaxial surface was irradiated, P n averaged 4.6% higher with the UV supplement that cut-off UV at 311 nm, compared to lower and higher UV wavelength supplements. This former supplement differed from higher wavelength supplements by primarily providing more UV between 320 and 350 nm. To assess the possibility of direct absorption of UV by photosynthetic pigments, we measured the absorbance of extracted chlorophylls. Chlorophyll a had absorbance peaks at 340 and 389 nm that were 49 and 72% of that at the sorét peak. Chlorophyll b had absorbance peaks at 315 and 346 nm that were both 35% of that at the sorét peak. Since the epidermis transmits some UV, the strong UV absorbance of chlorophyll implies a potential role for irradiance beyond the bounds of the conventionally defined photosynthetically active radiation waveband (400–700 nm). To assess the role of absorption of UV-induced blue fluorescence, we measured the UV-induced fluorescence excitation and emission spectra of leaves. Abaxial excitation peaked at 328 nm, while emission peaked at 446 nm. In this analysis, we used our abaxial fluorescence excitation spectrum and the UV photosynthetic inhibition spectrum of Caldwell et al. (1986) to weight the UV irradiance with each cut-off filter, thereby estimating the potential contribution of UV-induced blue fluorescence to photosynthesis and the inhibitory effects of UV irradiance on photosynthesis, respectively. With a non

  4. Numerical analysis of radiation propagation in innovative volumetric receivers based on selective laser melting techniques

    Science.gov (United States)

    Alberti, Fabrizio; Santiago, Sergio; Roccabruna, Mattia; Luque, Salvador; Gonzalez-Aguilar, Jose; Crema, Luigi; Romero, Manuel

    2016-05-01

    Volumetric absorbers constitute one of the key elements in order to achieve high thermal conversion efficiencies in concentrating solar power plants. Regardless of the working fluid or thermodynamic cycle employed, design trends towards higher absorber output temperatures are widespread, which lead to the general need of components of high solar absorptance, high conduction within the receiver material, high internal convection, low radiative and convective heat losses and high mechanical durability. In this context, the use of advanced manufacturing techniques, such as selective laser melting, has allowed for the fabrication of intricate geometries that are capable of fulfilling the previous requirements. This paper presents a parametric design and analysis of the optical performance of volumetric absorbers of variable porosity conducted by means of detailed numerical ray tracing simulations. Sections of variable macroscopic porosity along the absorber depth were constructed by the fractal growth of single-cell structures. Measures of performance analyzed include optical reflection losses from the absorber front and rear faces, penetration of radiation inside the absorber volume, and radiation absorption as a function of absorber depth. The effects of engineering design parameters such as absorber length and wall thickness, material reflectance and porosity distribution on the optical performance of absorbers are discussed, and general design guidelines are given.

  5. Corundum-based transparent infrared absorbers

    KAUST Repository

    Schwingenschlögl, Udo

    2009-10-01

    Hypothetical corundum-based compounds are studied by electronic structure calculations. One quarter of the Al atoms in Al2O3 is replaced by a 3d transition metal from the M = Ti, ..., Zn (d1, ..., d9) series. Structure optimisations are performed for all the M-Al2O3 compounds and the electronic states are evaluated. Due to the M substitutes, narrow partially filled bands are formed at the Fermi energy. Beyond, for M = Ni and M = Cu the optical properties of Al2O3 in the visible range are conserved, while for M = Ti, ..., Co the systems form high accuracy optical filters. Since the compounds absorb the infrared radiation, the M = Ni and M = Cu systems are good candidates for heat-protective coatings. © 2009 Elsevier B.V. All rights reserved.

  6. Diurnal changes of net photosynthetic rate (NPR) in leaves of Lonicera japonica Thunb. and the responding mathematical model of NPR to photosynthetic valid radiation

    International Nuclear Information System (INIS)

    Wu Dafu; Zhang Shengli; Li Dongfang

    2009-01-01

    [Objective] The study provided theoretical basis for production practice . [Method] With Lonicera japonica Thunb .as material, diurnal changes of net photosynthetic rate (NPR) in leaves of the plant and the responding mathematical model of NPR to photosynthetic valid radiation were studied using portable photosynthetic determinator system. [Result] Like most of C3 plants, the diurnal changes curve of NPR of Lonicera japonica Thunb .showed double peaks, but there were time difference in reaching the peak value between the study and previous ones . The responding mathematical model of NPR to photosynthetic valid radiation could be described by three mathematic functions, such as logarithm, linearity and binomial, but binomial function was more precise than the others. Light saturation point of Lonicera japonica Thunb. was figured out by binomial equation deduced in the study , and light saturation point was 1 086 .3 μmol/ (m2•s) . [Conclusion] The diurnal changes curve of NPR of Lonicera japonica Thunb .showed double peaks, and the responding mathematical model of NPR to photosynthetic valid radiation could be described by binomial functions

  7. Dosimetry of high energy radiation

    CERN Document Server

    Sahare, P D

    2018-01-01

    High energy radiation is hazardous to living beings and a threat to mankind. The correct estimation of the high energy radiation is a must and a single technique may not be very successful. The process of estimating the dose (the absorbed energy that could cause damages) is called dosimetry. This book covers the basic technical knowledge in the field of radiation dosimetry. It also makes readers aware of the dangers and hazards of high energy radiation.

  8. Calorimeter measurements of absorbed doses at the heavy water enriched uranium reactor; Kalorimetrijska merenja apsorbovanih doza u reaktoru na tesku vodu i obogaceni uran

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, V [Institute of Nuclear Sciences Boris Kidric, Odeljenje za radijacionu hemiju, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    Application of calorimetry measurements of absorbed doses was imposed by the need of good knowledge of the absorbed dose values in the reactor experimental channels. Other methods are considered less reliable. The work was done in two phases: calorimetry measurements at lower reactor power (13-80 kW) by isothermal calorimeter, and differential calorimeter constructions for measurements at higher power levels (up to 1 MW). This report includes the following four annexes, papers: Isothermal calorimeter for reactor radiation monitoring, to be published; Calorimeter dosimetry of reactor radiation, presented at the Symposium about nuclear fuel held in april 1961; Radiation dosimetry of the reactor RA at Vinca, published in the Bull. Inst. Nucl. Sci. 1961; Differential calorimeter for reactor radiation dosimetry.

  9. Transparent Metal-Salt-Filled Polymeric Radiation Shields

    Science.gov (United States)

    Edwards, David; Lennhoff, John; Harris, George

    2003-01-01

    "COR-RA" (colorless atomic oxygen resistant -- radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam welding and industrial and medical x-ray equipment. In comparison with lead-foil and leaded-glass shields that give equivalent protection against x-rays (see table), COR-RA shields are mechanically more durable. COR-RA absorbs not only x-rays but also neutrons and rays without adverse effects on optical or mechanical performance. The formulation of COR-RA with the most favorable mechanical-durability and optical properties contains 22 weight percent of bismuth to absorb x-rays, plus 45 atomic percent hydrogen for shielding against neutrons.

  10. Bayesian approach in MN low dose of radiation counting

    International Nuclear Information System (INIS)

    Serna Berna, A.; Alcaraz, M.; Acevedo, C.; Navarro, J. L.; Alcanzar, M. D.; Canteras, M.

    2006-01-01

    The Micronucleus assay in lymphocytes is a well established technique for the assessment of genetic damage induced by ionizing radiation. Due to the presence of a natural background of MN the net MN is obtained by subtracting this value to the gross value. When very low doses of radiation are given the induced MN is close even lower than the predetermined background value. Furthermore, the damage distribution induced by the radiation follows a Poisson probability distribution. These two facts pose a difficult task to obtain the net counting rate in the exposed situations. It is possible to overcome this problem using a bayesian approach, in which the selection of a priori distributions for the background and net counting rate plays an important role. In the present work we make a detailed analysed using bayesian theory to infer the net counting rate in two different situations: a) when the background is known for an individual sample, using exact value value for the background and Jeffreys prior for the net counting rate, and b) when the background is not known and we make use of a population background distribution as background prior function and constant prior for the net counting rate. (Author)

  11. 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

  12. Radiation-absorbed doses and energy imparted from panoramic tomography, cephalometric radiography, and occlusal film radiography in children

    International Nuclear Information System (INIS)

    Bankvall, G.; Hakansson, H.A.

    1982-01-01

    The absorbed doses and energy imparted from radiographic examinations of children, using panoramic tomography (PTG), cephalometric radiography (CPR), and maxillary frontal occlusal overview (FOO), were examined. The absorbed dose at various sites of the head were measured with TL dosimeters in a phantom and in patients. The energy imparted was calculated from measurements of areal exposure using a planparallel ionization chamber. The maximum absorbed doses for panoramic tomography were located around the lateral rotation center, for cephalometric radiography in the left (tube side) parotid region, and for frontal occlusal radiography in the nose. The absorbed doses in the eyes, thyroid gland, and skin are discussed and compared with previous reports and, for the most part, are found to be in agreement. The mean energy imparted from all three examination methods is 5 mJ with about 57 percent from panoramic, 33 percent from cephalometric, and 10 percent from frontal occlusal examinations. The energy imparted from cephalometric radiography can be reduced to about 10 percent with the use of an improved examination technique, leaving panoramic tomography responsible for contributing about 80 percent of the total energy imparted

  13. 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.

  14. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    International Nuclear Information System (INIS)

    Bero, M A; Abukassem, I

    2009-01-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  15. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    Science.gov (United States)

    Bero, M. A.; Abukassem, I.

    2009-05-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  16. Dependence of the coefficient of environmental thermal losses of radiation-absorbing thermal exchange panels of flat solar collectors for heating heat-transfer fluid from their average operating and ambient temperatures

    International Nuclear Information System (INIS)

    Avezova, N.R.; Avezov, R.R.

    2015-01-01

    The approximation formula is derived for calculating the normalized coefficient of thermal losses of flat solar collectors (FSCs) for heating heat-transfer fluid (HTF). These are used in hot water supply systems in the warmer part of the year, depending on the average working surface temperature of their radiation-absorbing thermal exchange panels (RATEPs) (t"-_w_s_r) and the ambient temperature (t_a_m_b) in their realistic variation range. (author)

  17. What is radiation curing

    International Nuclear Information System (INIS)

    Kinstle, J.F.

    1975-01-01

    Radiation curing is a highly interdisciplinary and sophisticated field. Successful interplay between chemists and engineers of various disciplines is required. Throughout the research-development-applications cycle, two disciplines for which hybridization is extremely important are radiation chemistry and polymer chemistry. The molecular level effects caused by absorbed radiation depend strongly on the type and intensity of the radiation. Efficient utilization of the radiation to effect desired transformations in a monomer and/or polymer system, and maximization of final properties, depend on well-planned polymer synthesis and system formulation. The elementary basis of these two disciplines and the manner in which they necessarily coalesce in the field of radiation curing are reviewed

  18. Personnel ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Williams, R.A.

    1975-01-01

    A dosimeter and method for use by personnel working in an area of mixed ionizing radiation fields for measuring and/or determining the effective energy of x- and gamma radiation; beta, x-, and gamma radiation dose equivalent to the surface of the body; beta, x-, and gamma radiation dose equivalent at a depth in the body; the presence of slow neutron, fast neutron dose equivalent; and orientation of the person wearing the dosimeter to the source of radiation is disclosed. Optionally integrated into this device and method are improved means for determining neutron energy spectrum and absorbed dose from fission gamma and neutron radiation resulting from accidental criticality

  19. The equivalency between logic Petri workflow nets and workflow nets.

    Science.gov (United States)

    Wang, Jing; Yu, ShuXia; Du, YuYue

    2015-01-01

    Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented.

  20. The Equivalency between Logic Petri Workflow Nets and Workflow Nets

    Science.gov (United States)

    Wang, Jing; Yu, ShuXia; Du, YuYue

    2015-01-01

    Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented. PMID:25821845