International Nuclear Information System (INIS)

Full text of publication follows: Radiation hardening and embrittlement due to high-energy neutron radiation around 623 K are the important issues on reduced-activation ferritic/martensitic (RAF/M) steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties of RAF/M after irradiation. It has been reported that the weld joint has less hardening than the base metal from the tensile test results of TIG weldments irradiated in HFIR. This report indicated that radiation hardening can be reduced by the optimization of heat treatment condition for F82H. The purposes of this study are to establish the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. The materials ...

Energy Technology Data Exchange (ETDEWEB)

Dilute caustic high-level radioactive waste slurries can induce pitting corrosion in carbon steel. Cyclic potentiodynamic polarization tests were conducted in simulated and actual waste solutions to determine minimum concentrations of sodium nitrate which inhibit pitting in ASTM A537 class 1 steel exposed to these solutions. Susceptibility to pitting was assessed through microscopic inspection of specimens and inspection of polarization scans. Long-term coupon immersion tests were conducted to verify the nitrite concentrations established by the cyclic potentiodynamic polarization tests. The minimum effective nitrite concentration is expressed as a function of the waste nitrate concentration and temperature.

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The performance of four different organic coating systems applied to carbon and weathering steel coupons has been assessed in this investigation. applied on the surface of carbon steel and weathering steel coupons. The coupons have been evaluated using five different tests, three field tests and two accelerated tests. The field tests were carried out at three atmospheric stations, located at COSIPA in Cubatao-SP, at Alto da Serra in Cubatao-SP and at Paula Souza in Sao Paulo city. The accelerated tests consisted of (a) exposure to alternate cycles of ultraviolet radiation/condensation combined with salt spray cycles (UVCON combined with Salt Spray) and of (b) exposure to alternate cycles of ultraviolet radiation/condensation combined with the Prohesion test. The performance of the coatings was assessed by visual observation and photographs, using a method based on ASTM D-610, ASTM ...

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Pitting behavior of alloy 800 was investigated as a function of temperature and prefilming in high-temperature water. The behavior was characterized in terms of pitting potential (U{sub p}) and pit density (n{sub p}). U{sub p} decreased with increasing temperature and chloride activity. Prefilming of test coupons over a period between 100 h and 5,000 h in ammoniated water at 300 C had no apparent influence on U{sub p} at room temperature, 180 C, and 300 C. However, the number of pits in prefilmed coupons was much higher than in coupons covered with an air passive layer. The effect of prefilming on pit nucleation was investigated in detail with regard to a model and test methods developed by Bianchi, et al. Density of pits in prefilmed coupons was at least 1 order of magnitude higher than in air passive coupons. Maximum pit density was measured after a prefilming period of 100 h. The ...

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This chapter is concerned with standards and guidances for limiting radiation exposures. It is divided into three sections, each of which has several parts. Section 1: Ionizing Radiation -- Standards and Guidances Applicable to the Public: Part A, Radiation Protection Standards; Part B, Environmental Radiation Standards; Part C, Exempt Levels of Radioactivity; Part D, Protective Action Guides for Accidents. Section 2: Ionizing Radiation -- Standards Applicable to the Workplace. Section 3: Medical and Other Standards.

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This volume presents the collations tables of a six volume comparative epidemiological survey of the effects of low level radiation dose. Data are collated for the effects observed in the following irradiated groups:- Preconception irradiation, intra-uterine irradiation, childhood irradiation, adult irradiation. (UK).

International Nuclear Information System (INIS)

... range 01-10 nuclei photons radiation sources recoils resonance scattering

International Nuclear Information System (INIS)

In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of "6Li and "7Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of "6Li and "7Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)

International Nuclear Information System (INIS)

In this project, measurement of x-ray radiation dose level during radiological examination in Jos university teaching hospital and Plateau State specialist hospital at different locations within the department were carried out using radiation survey meter. The results were converted from micro sievert per hour (#mu#Sv/hr) to milisievert per year (mSv/yr). The radiation levels from the two hospitals visited ranged from 1.3m Sv/yr to 8.4m Sv/yr. This implies that all the radiology departments visited are still operating within the safety limit having less than 20 mSv/yr which is the standard permissible radiation level recommended per year.

International Nuclear Information System (INIS)

The document published under A/63:46 and titled report of the scientific committee of United Nations for the study of ionizing radiations effects, gives the situation of the fifty sixth session of the committee that stood at Vienna from the 10. to 18. july 2008. In the chapter 3 of this report the writers summarize the strategic planning and the working program of the scientific committee for the period 2009-2013. They note that the committee worry about the inadequate means, particularly in personnel. The priorities for the given period will be the medical exposure of patients, the radiation levels and the effects of energy production, the exposure to natural radiation sources and the improvement of the understanding of the effects of the low doses radiation exposure. (N.C.)

International Nuclear Information System (INIS)

In order to prevent corrosion failures of machines and structures, it is desirable to know in advance when the corrosion damage will take place, and appropriate measures are needed to mitigate the damage. The corrosion predictions are needed both at development as well as operational stage of machines and structures. There are several forms of corrosion process through which varying degrees of damage can occur. Under certain conditions these corrosion processes at alone and in other set of conditions, several of these processes may occur simultaneously. For a certain type of machine elements and structures, such as gears, bearing, tubes, pipelines, containers, storage tanks etc., are particularly prone to pitting corrosion which is an insidious form of corrosion. The corrosion predictions are usually based on experimental results obtained from test coupons and/or field experiences of similar machines or parts of a structure. Considerable scatter is observed in ...

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In future experiments the readout electronics for pixel detectors is required to be resistant to a very high radiation level. In this paper we report on irradiation tests performed on several preFPIX2 prototype pixel readout chips for the BTeV experiment exposed to a 200 MeV proton beam. The prototype chips have been implemented in commercial 0.25 {micro}m CMOS processes following radiation tolerant design rules. The results show that this ASIC design tolerates a large total radiation dose, and that radiation induced Single Event Effects occur at a manageable level.

Science.gov (United States)

... main in this state only for 10-8 secs., after which they decay to the meta- stable state (fluorescent level) because of spontaneous radiation or other ...

International Nuclear Information System (INIS)

Microprocessor based ''smart'' pressure, level, and flow transmitters were tested to determine the radiation hardness of this class of electronic instrumentation for use in reactor building applications. Commercial grade Complementary Metal Oxide Semiconductor (CMOS) integrated circuits used in these transmitters were found to fail at total gamma dose levels between 2500 and 10,000 rad. This results in an unacceptably short lifetime in many reactor building radiation environments. Radiation hardened integrated circuits can, in general, provide satisfactory service life for normal reactor operations when not restricted to the extremely low power budget imposed by standard 4--20 mA two-wire instrument loops. The design of these circuits will require attention to vendor radiation hardness specifications, dose rates, process control with respect to ...

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Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. We have discovered that sublethal doses of whole body irradiation with x-rays also elevates ZPP 2-3-fold over normal levels. The ZPP level does not begin to increase until days 12-14 postirradiation and peaks between days 18 and 20 before returning to normal levels between days 28 and 35. Increasing the radiation dose delays the onset of the rise in ZPP, but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms that cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation-induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the ...

International Nuclear Information System (INIS)

The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave ...

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MPFDs are a new class of detectors that utilize properties from existing radiation detector designs. A majority of these characteristics come from fission chamber designs. These include radiation hardness, gamma-ray background insensitivity, and large signal output.

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A historical perspective is given of the current paradigm that does not explicitly protect the environment from radiation, but instead, relies on the concept that if dose limits are set to protect humans then the environment is automatically protected as well. We summarize recent international questioning of this paradigm and briefly present three different frameworks for protecting biota that are being considered by the U.S. DOE, the Canadian government and the International Commission on Radiological Protection. We emphasize that an enhanced collaboration is required between what has traditionally been separated disciplines of radiation biology and radiation ecology if we are going to properly address the current environmental radiation problems. We then summarize results generated from an EMSP grant that allowed us to develop a Low Dose Irradiation Facility that specifically addresses effects of ...

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This book presents the basic ideas of the physics of non-gravitational perturbations and the mathematics required to compute their orbital effects. It conveys the relevance of the different problems that must be solved to achieve a given level of accuracy in orbit determination and in recovery of geophysically significant parameters. Selected Contents are: Orders of Magnitude of the Perturbing Forces, Tides and Apparent Forces, Tools from Celestial Mechanics, Solar Radiation Pressure-Direct Effects: Satellite-Solar Radiation Interaction, Long-Term Effects on Semi-Major Axis, Radiation Pressure-Indirect Effects: Earth-Reflected Radiation Pressure, Anisotropic Thermal Emission, Drag: Orbital Perturbations by a Drag-Like Force, and Charged Particle Drag.

International Nuclear Information System (INIS)

This research report discusses the radiation hardening of a commercially available mobile robot, the REMOTEC ANDROS. This hardening effort is culminating in the availability of a megarad hardened mobile platform to access areas in nuclear facilities with extremely high levels of radiation (0.1 to 1 Mrad). These radiation levels may be encountered both during routine repair and monitoring activities and accident situations. The project has completed a phase-I U.S. Department of Energy Small Business Innovative Research contract and is now in a phase-II effort with completion scheduled in early 1995. The research involves the evaluation of the material and electrical components of an ANDROS robot to determine the anticipated radiation hardness of the current production version and evaluation of the components that must be replaced or modified to harden the system ...

International Nuclear Information System (INIS)

Alanine/EPR Dosimetry system is classified as a reference-standard dosimeter which used to calibrate radiation environments and to calibrate routine dosimeters in absorbed dose range of 1 to 105 Gy. Characteristics of Alanine/EPR dosimetry system are better suitable than routinely used personnel dosimeters for the long term radiation measurement in harsh condition of Nuclear power plant : This system is not significantly affected by temperature and humidity and also has low fading rate. About 1 year ago, Alanine and Lithium compound dosimeters were installed at Wolsung unit 1 for the environment monitoring as a part of equipment qualification program. 35 positions which are most severe and representative cable positions were chosen for radiation and temperature monitoring. The recovered alanine dosimeter in the period of maintenance was measured by E-scan alanine analyzer system, Meanwhile measurement result shows extremely ...

British Library Electronic Table of Contents (United Kingdom)

Using longitudinal data from Ukraine we examine the extent of any long-lasting effects of exposure to the Chernobyl disaster on the health and labour market performance of the adult workforce. Variation in the local area level of radiation fallout from the Chernobyl accident is considered as a random exogenous shock with which to try to establish its causal impact on poor health, labour force participation, hours worked and wages. There appears to be a significant positive association between local area-level radiation dosage and perception of poor health, though much weaker associations between local area-level dosage and other specific self-reported health conditions. There is also some evidence to suggest that those who lived in areas more exposed to Chernobyl-induced radiation have sig...

International Nuclear Information System (INIS)

The radiation hardening studies started in the mid decade 1960-1970. To survive the different military or space radiative environment, a new engineering science was born, to understand the degradation of electronics components. The different solutions to improve the electronic behavior in such environments have been named 'radiation hardening' of the technologies. Improvement of existing technologies, and qualification methods have been widely studied. However, on the other hand, specific technologies were developed: the Silicon On Insulator technologies for CMOS or Bipolar. The HSOI3HD technology offers today the highest hardening level for the integration density of hundreds of thousand transistors on the same silicon. Full complex systems could be produced on a single die with a technological radiation hardening and no more system hardening.

International Nuclear Information System (INIS)

Radiation decontamination of dry ingredients, herbs and enzyme preparations is a technically feasible, economically viable and safe physical process. The procedure is direct, simple, requires no additives and is highly efficient. Its dose requirement is moderate. Radiation doses of 3-10 kGy (0.3-1 mrad) have proved sufficient to reduce the viable counts to a satisfactory level. Ionising radiations do not cause any significant rise in temperature. The flavour, texture or other important technological or sensory properties of most ingredients are not influenced at radiation doses necessary for satisfactory decontamination, and radiation obviates the chemical residue problem. The microflora surviving radiation decontamination of dry ingredients are more susceptible to subsequent antimicrobial treatments. Recontamination can be prevented as the ...

International Nuclear Information System (INIS)

Radioactive waste shipping and receiving facilities presently planned for commercial and defense high-level nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. If current limits for radiation levels at the cask surface and current handling methods are used, high cumulative personnel exposure to ionizing radiation is projected to occur. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations, suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and ...

Energy Technology Data Exchange (ETDEWEB)

A comparitive analysis is made of the principal characteristics of narrow-band and conventional semiconductor light amplifiers. It is shown that quasi-distributed filtering of the spontaneous radiation ensures a high gain and a low level of the spontaneous noise at the amplifier output.

UK PubMed Central (United Kingdom)

Although salamanders are characteristic amphibians in Holarctic temperate habitats, in tropical regions they have diversified evolutionarily only in tropical America. An adaptive radiation centered...Full Text Available

International Nuclear Information System (INIS)

Radiation exposure control is one of the most important aspects in any nuclear facility . It encompasses continuous monitoring of the various areas of the facility to detect any increase in the radiation level and/or the air activity level beyond preset limits and alarm the O and M personnel working in these areas. Detection and measurement of radiation level and the air activity level is carried out by a number of monitors installed in the areas. These monitors include Area Gamma Monitors, Continuous Air Monitors, Pu-In-Air Monitors, Criticality Monitors etc. Traditionally, these measurements are displayed and recorded on a Central Radiation Protection Console(CRPC), which is located in the central control room of the facility. This methodology suffers from the shortcoming that any worker required to enter a work area ...

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The author describes the history of the Soviet Unions nuclear weapons testing in Siberia from the first bomb on 29th August 1949 until the test-ban treaty of 1963. The effects of the weapons testing on the local population is only now becoming widely known. Levels of cancers and cataracts are significantly higher than in uneffected populations, and there are also high levels of some lung, bone, skin and digestive conditions. Perhaps the most important information relates to cataracts, previously thought to be caused by single large bursts of radiation. Regulatory authorities worldwide will need to tighten the safety limits for eye radiation exposure to these findings. (U.K.).

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Pollen from four temperate-latitude taxa were treated with UV radiation in a portion of the UV-B (280-320 nm) waveband during in vitro germination. Inhibition of germination was noted in this pollen compared to samples treated identically except for the exclusion of the UV-B portion of the spectrum. Levels similar to maximum solar UV-B found in temperate-latitude areas failed to inhibit pollen germination significantly, while levels similar to maximum solar UV-B found in equatorial alpine locations caused partial inhibition of germination in three of the four taxa examined.

Energy Technology Data Exchange (ETDEWEB)

The radiation degradation behavior of three commercial polyvinyl chloride (PVC) materials has been investigated. All three exhibit an interesting reversal in the trend of the tensile strength part way through the aging experiment: the tensile strength first drops, then rises. The early drop is associated with oxidative scission; the rise is associated with crosslinking and is preceded by the material reaching the gel point. It was also found that the tensile elongation tended to level out in advanced stages of aging with the leveling-out values dependent on the dose rate. These phenomena pose complications for the design of accelerated aging tests.

British Library Electronic Table of Contents (United Kingdom)

Resonant scattering of atoms with formation of the Feshbach resonance in the presence of a laser radiation coupling the levels of two bound atoms (a molecule) is considered. The laser field leads to a second resonance in scattering and broadening of resonances, which facilitates the possibility of experimental observation of asymmetry of the total scattering cross-section arising because of interference between resonant and potential scatterings. The effects associated with interference of the two channels of decay of a bound system of two atoms (a molecule) in the laser field are studied. An expression is obtained for the scattering length in collision of two cold atoms in the field of laser radiation.

International Nuclear Information System (INIS)

Argon ions irradiation of 12% Cr steels and Fe/Cr alloys results in the hardening up to 10000 MPa. This value exceeds the hardening level even for martensitic transformation. Along with the increase of microhardness following irradiation the shape of X-ray graph of the affected materials changes considerable. Hardening value and behavior are determined by temperature radiation doze, preliminary ageing, extent of cold strain and alloying. The odserved phenomenon is supposed to be caused by irradiation-induced structural transformations. Reversibility of radiation hardening of the materials in question was observed.

Science.gov (United States)

Some aspects of molecular mechanisms common to radiation and chemical carcinogenesis are discussed, particularly the DNA damage done by these agents. Emphasis is placed on epidemiological considerations and on dose-response models used in risk assessment to extrapolate from experimental data obtained at high doses to the effects from long-term, low-level exposures. 3 references, 6 figures. (ACR)

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This document presents the SSI preliminary views and position concerning the decommissioning of nuclear plants. To prevent the exposure of the decommissioning personnel and the general public to unacceptable levels of radiation and to protect the environment and future generations, it is SSI`s task to formulate and issue the necessary terms and regulations with which the reactor licensees must comply during the decommissioning work. The views and principles presented here are the basis of SSI`s continued work on guidelines and regulations for the decommissioning of nuclear plants.

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Many assays for oncogenic transformation have been developed ranging from those in established rodent cell lines where morphological alteration is scored, to those in human cells growing in nude mice where tumor invasiveness is scored. In general, systems that are most quantitaive are also the least relevant in terms of human carcinogenesis and human risk estimation. The development of cell culture systems has made it possible to assess at the cellular level the oncogenic potential of a variety of chemical, physical and viral agents. Cell culture systems afford the opportunity to identify factors and conditions that may prevent or enhance cellular transformation by radiation and chemicals. Permissive and protective factors in radiation-induced transformation include thyroid hormone and the tumor promoter TPA that increase the transformation incidence for a given dose of radiation, and retinoids, ...

Science.gov (United States)

Endothelial dysfunction and increased platelet aggregation may be involved in the pathogenesis of normal tissue radiation toxicity. This study assessed clopidogrel, an inhibitor of ADP-induced platelet aggregation, as a modulator of intestinal radiation injury (radiation enteropathy). Rat small intestine was exposed to 21 Gy X-radiation. Clopidogrel (20 mg/kg/day) or vehicle was administered from 2 days before to 10 days after irradiation. Structural radiation injury, neutrophil infiltration, smooth muscle cell proliferation, collagen content, and TGF-beta1 expression were assessed 2 weeks (early phase) and 26 weeks (delayed phase) after irradiation, using quantitative histology and immunohistochemistry, morphometry, and real-time fluorogenic probe RT-PCR. Irradiated intestine exhibited significant histopathologic injury, reduced mucosal surface area, vascular sclerosis, intestinal ...

Science.gov (United States)

Ramsar, a city in the northern Iran, has the highest level of natural background radiation in the world. It has been clearly shown that low doses of ionising radiation can induce resistance to subsequent higher exposures. This phenomenon is termed radioadaptive response. We have compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-ray occupational exposure as conditioning doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in normal background radiation areas, 15 healthy individuals from Talesh Mahalleh, a region with extraordinary high level of background radiation, and 7 X-ray radiographers working in Ramsar hospital located in normal natural background ionising radiation area were evaluated. Peripheral blood ...

International Nuclear Information System (INIS)

The results of photoneutron spectra measurements for the reaction (#gamma#,n) on the Sr-88 nuclei near threshold are presented. The parameters of resonance levels, as well as radiative S_#gamma#"("1") and neutron S_n"("1") strength functions for transitions on the first excited level of Sr-87 were obtained. 2 refs.; 1 fig.; 1 tab.

International Nuclear Information System (INIS)

We discuss the use of active control to reduce mirror position fluctuations at the quantum level. We have shown in a recent experiment that it is possible to reduce the thermal noise of a mirror by measuring and controlling its motion with an optomechanical sensor based on a high-finesse optical cavity. This approach can be extended to lock the mirror motion at the quantum level, and to suppress the quantum effects of radiation pressure in interferometric measurements such as gravitational-wave detectors. The sensitivity improvement is furthermore independent of losses in the interferometer.

Energy Technology Data Exchange (ETDEWEB)

A test to determine the lithium compatibility and impurity gettering capabilities of various materials including yttrium was performed in Beryllium-7 Experimental Lithium (7BELL) at 270/sup 0/C. Yttrium coupons were exposed in liquid lithium for a total of 3,718 hours. X-ray diffraction and bulk chemical analysis data indicated that yttrium absorbs hydrogen from liquid lithium at 270/sup 0/C and transforms to yttrium dihydride (YH/sub 2/). The transformation of yttrium to YH/sub 2/ resulted in embrittlement of the coupons and subsequent fragmentation to small pieces. Additional analysis, based on the equilibrium hydrogen pressures for the transition of yttrium to YH/sub 2/, and Sievert's relationship for hydrogen in equilibrium with hydrogen in lithium, indicates that the temperature of yttrium cannot exceed 280/sup 0/C to control the hydrogen concentration in lithium at below 1 wt ppm. It is concluded in general that yttrium in sponge ...

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The effects of therapeutic levels of radiation on the axial properties of the primate vertebral column were studied. Seven male rhesus monkeys (Macaca mulatta) were irradiated with a single does of 1300 cGy to the specific lumbar vertebrae of L2, L3, and L4. Three additional animals served as controls. Radiographs were taken before the radiation treatment and just prior to sacrifice to determine density changes in the bone. The animal subjects were sacrificed 105 days following the radiation exposure. Biomechanical testing was completed on lumbar levels 2 and 3 to identify changes in strength characteristics following radiation treatment. Histomorphometric analysis of lumbar vertebrae level 4 was completed to identify volume and surface density changes as well as cellular changes. Tetracycline, dicarbomethylaminomethyl fluorescein (DCAF), ...

International Nuclear Information System (INIS)

Estimations on the somatic and genetic effects of small doses of ionizing radiations in Man have been proposed by the Advisory Committee on the Biological Effects of Ionizing Radiation, set up by the U.S. National Academy of Sciences. They have been published in an important report, issued in 1972, from which we briefly analyze here the Chapter dealing with the somatic effects. Small doses of raditions are expected to promote only carcinogenic effects. After a rapid survey of the human experience on which the estimations are based, as regards the latent period of cancers, the plateau region (period of high risk) and the absolute and relative risk expressed per rem, per 10"6 persons, per year, for leukaemia (having the highest risk) and for the ''other cancers''. These estimations were obtained by linear extrapolation to the 1 rem level from observations made after irradiation at relatively high dose ...

International Nuclear Information System (INIS)

Recent research findings of epidemiologist Alice Stewart suggest that nuclear workers may be at risk of contracting cancer even though their measured occupational doses fall within current safety standards. It is argued that these standards are inappropriate as they are based on extrapolations of studies on survivors of the Hiroshima and Nagasaki explosions. These individuals received single doses of radiation, whereas today's nuclear industry personnel are exposed to low-level ionizing radiation over the length of their working lives. Stewart's team linked low dose occupational exposure to ionizing radiation with an increased risk of cancer in respiratory, digestive and blood-forming tissues. The nuclear industry and United States government agencies hotly contest these assertion with their potentially damaging political and economic consequences. (UK).

Energy Technology Data Exchange (ETDEWEB)

The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.

International Nuclear Information System (INIS)

Coherent spontaneous radiation has now been observed in several FELs, and is a subject of great importance to the design of self-amplified spontaneous emission (SASE) devices. We report observations of coherent spontaneous radiation in both FIREFLY and the mid-infrared FEL at the Stanford Picosecond FEL Center. Coherent emission has been observed at wavelengths as short as 5 microns, and enhancement over incoherent levels by as much as a factor of 4x10"4 has been observed at longer wavelengths. The latter behavior was observed at 45 microns in FIREFLY with short bunches produced by off-peak acceleration and dispersive compression. We present temporal measurements of the highly bunched electron distributions responsible for the large enhancements, using both transition radiation and energy-phase techniques.

International Nuclear Information System (INIS)

Radioactive waste shipping and receiving facilities presently planned for commercial and defense nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. Unacceptable personnel exposure to ionizing radiation is projected to occur if current limits for radiation levels at the cask surface and current handling methods are used. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels, while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and unloading operations in a remote and ...

Energy Technology Data Exchange (ETDEWEB)

The macroscopic stress distribution across an annealed Zircaloy-4 gas tungsten arc weld was measured by neutron time-of-flight diffraction at the SMARTS diffractometer at Los Alamos National Laboratory. The stresses after annealing are about 40% lower than those in the same weld prior to heat treatment. The intergranular strains in the reference coupons, which give the macroscopic stress free lattice spacings, are consistent with the difference in cooling the strongly textured plate and the weakly textured weld.

International Nuclear Information System (INIS)

In May 1990 a group of scientists representing several federal agencies, the International Society of Regulatory Toxicology and Pharmacology, the private sector, and academia met to develop a strategy to encourage the study of the biological effects of low level exposures (BELLE) to chemical agents and radioactivity. A workshop was held in 1991 with seven invited speakers focusing on the toxicological implications of biological adaptations. The selection of topics and speakers was designed to consider critically the concept of hormesis, not only in a broad, conceptual manner, but also at the molecular and biochemical levels. These presentations offered a complementary perspective on the diverse range of molecular mechanisms that can become activated at low levels of toxicant exposure. In addition to chemical toxicology research, an overview of current research on 'Effects of low-dose radiation on the ...

Energy Technology Data Exchange (ETDEWEB)

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 Nuclear Information System (INIS)

The genetically significant dose (GSD) is an index variable which exclusively allows to describe the genetic risk in the progeny of a population due to the application of ionizing radiation and radioactive substances in one part of this population. It may result in wrong interpretation of population exposure at increasing incidence of examinations in a population involving ionizing radiation and radioactive drugs at simultaneously increasing application of alternative methods in children and adolescents owing to the fact that it indicates a downward trend although somatic exposure of this population has increased. Therefore, it is recommended to state both the GSD and the level of somatic radiation exposure of the population taken from the individual sources for the comparison and assessment of radiation exposure from various sources in future. Although the somatically significant ...

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The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the ...

Energy Technology Data Exchange (ETDEWEB)

A new method of determining the nuclear level density is presented. This method is based on the statistical analysis of the partial width fluctuations appearing in an excitation function of the radiative proton capture. The method was applied in the case of the /sup 88/Sr(p,..gamma..sub(..omega..))/sup 89/Y and /sup 89/Y(p,..gamma..sub(..omega..))/sup 90/Zr reactions. The density of levels with spin I/sup -/ in /sup 90/Zr and the densities of levels with spins 1/2/sup +/ and 3/2/sup +/ in /sup 89/Y at excitation energies from 10.9 to 11.6 MeV and from 9.3 to 10.8 MeV respectively, were determined with an uncertainty of about 35%.

Science.gov (United States)

Spontaneous emission in photonic crystals with anisotropic three-dimensional dispersion relation is studied. If the upper level is below a characteristic frequency omega(1), or above omega(2), or between omega(1) and omega(2), the radiation is a localized field with a frequency in the band gap, or a propagating field with a frquency in the band, or a diffusion field, respectively. An analytical expression for the Lamb shift is obtained. The Lamb shift for the current case is small compared to that in an ordinary vacuum or in one- or two-dimensional photonic crystals due to lower density of states. PMID:11017227

International Nuclear Information System (INIS)

The theory of spontaneous decay is studied using both quantum electrodynamics (QED) and semiclassical theories of radiation. There are qualitative differences between the theories in the prediction of interference phenomena. In QED, systems which were excited with pulsed laser light do not exhibit quantum interference effects associated with lower state splittings. On the other hand, semiclassical treatments of spontaneous decay do indicate the existence of interference effects not present in QED. In addition to this, differences are found between the predictions of fluorescence intensity in the presence of lower-state level crossings under continuous excitation. (U.S.).

Science.gov (United States)

The ionization, excitation, and radiative recombination rates for highly stripped ions are cal- culated with Maxwellian and non-Maxwellian electron distribution functions of the type Cmexp(-vm/wm) (2<=m<=5) as encountered in laser-heated plasmas and certain types of turbulent plasmas. The direct-radiative-recombination rates are found to decrease by at most 30% as m is increased from 2 to 5. On the other hand, the ionization and excitation rates are found to be strongly reduced if the transition energy ? exceeds twice the local temperature kBTe. The effect of this on the distribution of energy levels and degrees of ionization in laser-produced plasmas could be important.

Energy Technology Data Exchange (ETDEWEB)

The electronic structure of the clusters (V/sub 3/Si/sub 4/)/sup 12 -/, (Nb/sub 3/Sn/sub 4/)/sup 12 -/(Mo/sub 3/Ge/sub 4/)/sup 15 -/ in crystalline V/sub 3/Si, Nb/sub 3/Sn, Mo/sub 3/Ge compounds is calculated by the Extended Hueckel method. The influence of different types of radiation induced defects on the density of states at the Fermi level (the anti-site defects, the displacement of atoms in linear chains, the vacancy-interstitial type defects) is considered.

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The procedure was developed to enable STUK (Radiation and Nuclear Safety Authority) to make simplified estimates on off-site consequences based on the existing results of the PSA level 2 calculations done by e.g. power utilities. Method is based on dose calculated from each nuclide group of reactor activity inventory when the same release fraction for each group is assumed. This means that a specific new result from PSA level 2 can be categorised to find out a representative PSA level 3 result for this case. In addition a user interface including the procedure was prepared. Secondly some new insights about consequences based on the releases from PSA level 2 is expected to give better understanding of risks at prevailing increased reactor power levels. In this case only some early health effects and long-term doses were estimated without full-scope PSA ...

International Nuclear Information System (INIS)

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).

Energy Technology Data Exchange (ETDEWEB)

Concerning the gamma emitters, the only analysis on soils put in evidence the presence of cesium-137 ({sup 137}Cs), that does not come from the cyclotron functioning but from past man action as the Chernobylsk accident and the nuclear weapon tests in atmosphere. Independently of the functioning of the installation, we observe an increase of the ambient gamma radiation only near radioactive waste storage. It results of the storage of the former cyclotron elements. The induced increase is moderated because at 5 meters the values do not exceed the background noise. In relation with the functioning of the installation an increase of the ambient gamma radiation is noticed. Two causes are to considered: the release of radionuclides in atmosphere with gaseous effluents and the radiance of radiation sources inside the building. After the stopping of the installation (48 h at least), no increase of gamma ...

International Nuclear Information System (INIS)

This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the head. It is emphasised ...

International Nuclear Information System (INIS)

This report is the result of field work performed at the former White Point Nike Missile Site, San Pedro, California. The Hazardous Waste Remedial Actions Program tasked the Oak Ridge National Laboratory Pollutant Assessments Group in Grand Junction, Colo., with this project. The objective was to determine whether or not radioisotopes possibly associated with past Department of Defense (DOD) operations were present and within accepted background levels. The radiation survey was accomplished by performing three independent radiation surveys, both outdoors and indoors, and random soil sampling. Initially, the site was land surveyed to develop a grid block system. A background radiation investigation was performed out in the San Pedro area.

British Library Electronic Table of Contents (United Kingdom)

Abstract: The ability of melatonin as a potent antioxidant was used as a rationale for testing its antiapoptotic ability in normal cells. Recently, melatonin was shown to possess proapoptotic action by increasing reactive oxygen species in certain cancer cells. The modification of radiation-induced apoptosis by melatonin and the expression of apoptosis-associated upstream regulators were studied in normal mice splenocytes and Jurkat T leukemia cells. C57BL/6 mice were exposed to a single whole body X-ray radiation dose of 2 Gy with or without 250 mg/kg melatonin pretreatment. The Jurkat cells were divided into four groups of control, 1 mm melatonin alone, 4 Gy irradiation-only and melatonin pretreatment before irradiation. The highest level of apoptosis in the normal splenic white pulp was...

Energy Technology Data Exchange (ETDEWEB)

The serum levels of ferritin in 394 patients, including 339 patients with various malignant tumors and 23 with various non-malignant diseases, and 32 healthy subjects were determined. The normal levels of ferritin were 82.7 +- 42.3 ng/ml for males and 42.0 +- 36.9 ng/ml for females. The positive ratio of serum ferritin level was 28% in patients with malignant tumors and 22% in patients with non-malignant diseases. The usefulness of serum ferritin assay in screening for malignant tumors appeared to be limited. High serum levels of ferritin were found in patients with malignant lymphoma (positive ratio: 42%), pulmonary cancer (38%) and esophageal cancer (37%). According to the histological types, epidermoid cancer appeared to produce a higher serum level of ferritin than adenocarcinoma in patients with pulmonary cancer. It was interesting that malignant lymphoma had a high serum ...

Energy Technology Data Exchange (ETDEWEB)

Long-Range Alpha Detector (LRAD) systems are designed to monitor alpha contamination by measuring the number of ions in the air. Alpha particles are a form of ionizing radiation and a typical 5-MeV alpha particle will create about 150,000 ion pairs in air. Field tests at various DOE sites have shown that LRAD Surface Soil Monitors (SSM), Sample Monitors, and Object Monitors are faster and more sensitive than traditional alpha detectors for measuring alpha contamination. This paper discusses the various applications of LRAD technology to low-level radioactive waste management.

International Nuclear Information System (INIS)

Electron beams as a source of directed energy are under study at the Lawrence Livermore National Laboratory (LLNL). An intense 10-kA, 50-MeV, 50-ns full-width half-maximum, pulsed electron beam is generated by the prototype Advanced Test Accelerator (ATA) at the Laboratory's Site 300. Whenever the electron beam is stopped in materials, intense radiation is generated. Estimates based on available data in the literature show that for materials such as lead, photon radiation (x ray, gamma, bremsstrahlung) levels can be as large as 10"4 roentgens per pulse at 1 m in the zero-degree direction (i.e., the electron-beam direction). Neutrons, which are emitted isotropically, are produced at a level of 10"1"3 n/m"2 per pulse. Depending upon the number of pulses and the shielding geometry, the accumulated dose is potentially lethal to personnel and potentially damaging to instrumentation that may be used for ...

International Nuclear Information System (INIS)

Radionuclide (R) sorption from a solution (vapor) by freshly formed crystals with production of substitution solid solutions under different types of self-disordering is studied. Changes of self-defectiveness and macrodefectiveness with time and effect of radiation defects in the presence of P macroquantities are taken into account. An analysis for monodispersed sorbents is performed. It is shown that the achievement of equilibrium within a reasonable time in impurity-solid phase system depends on defectiveness which ensures a required level of the coefficient of impurity diffusion in sorbent crystals.

International Nuclear Information System (INIS)

Intrinsic crossluminescence (CRL) of CsBr, CsCl, and of BaF_2 was investigated with electron-beam and synchrotron radiation excitation. From the CRL spectra, the excitation spectra and the reflectivity, energy level schemes were deduced. Extrinsic CRL was observed changing either the initial (CsCl:Br"-) or the final (RbCl:Cs"+; KCl:Cs"+) state of CRL by doping. (author).

International Nuclear Information System (INIS)

The Steam Generator (SG) serves as an interface between primary and secondary cycle in Pressurized Heavy Water Reactor (PHWR). Failure of steam generator tubes result in leaking of active heavy water in the secondary closed loop. In Tarapur Atomic Power Station-3 and 4 (TAPS- 3 and 4), Scintillator detectors are provided to detect on line heavy water leakages in SG and moderator heat exchangers by monitoring Nitrogen-16 (16N) and Oxygen-19 (19O) activities. Efficacy of detection of these activities at designed detector position on SG blow down line in presence of background radiation field is analysed theoretically. The count rate of 19O and 16N estimated at the detector position inside Reactor Building (RB) shows that detectors only respond to very high leak rates due to presence of high ambient radiation level even though sensitivity is appreciably good. For detector position in RB in the accessible areas and out side the ...

Energy Technology Data Exchange (ETDEWEB)

The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the ...

Science.gov (United States)

The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm-2. Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing. We find that increased aerosol loading is associated with taller cloud towers and ...

International Nuclear Information System (INIS)

The survivability of the final optic, which must sit in the line of sight of high-energy neutrons and gamma rays, is a key issue for any laser-driven inertial fusion energy (IFE) concept. Previous work has concentrated on the use of reflective optics. Here, we introduce and analyze the use of a transmissive final optic for the IFE application. Our experimental work has been conducted at a range of doses and dose rates, including those comparable to the conditions at the IFE final optic. The experimental work, in conjunction with detailed analysis, suggests that a thin, fused silica Fresnel lens may be an attractive option when used at a wavelength of 351 nm. Our measurements and molecular dynamics simulations provide convincing evidence that the radiation damage, which leads to optical absorption, not only saturates but that a 'radiation annealing' effect is observed. A system-level description is provided, including ...

International Nuclear Information System (INIS)

Increased levels of epidermal growth factor receptor have been reported in a variety of tumors, including pulmonary squamous cell carcinomas in man. The purpose of this study was to determine if increased levels of epidermal growth factor (EGFR) were present in lung tumors from Beagle dogs that had been exposed to "2"3"9PuO_2- Using immunohistochemical techniques, sections from 17 lung tumors were examined for the presence of EGFR. Seven of the tumors were strongly positive for EGFR; the remainder of the tumors and the normal lung sections were negative. The positive immunostaining could not be correlated with the histologic phenotype of the tumors. Work is in progress to determine the level of EGFR in preneoplastic, proliferative epithelial foci in the Iung. (author)

International Nuclear Information System (INIS)

The risks from mining and processing of ores is reviewed on a generic basis with particular reference to some of the confusions which can arise due to lack of consistency or common logic in the use of exclusion, exemption and clearance. The difference in exclusion and exemption are challenged by comparing doses received in high background radiation areas and the doses received from a mining practice. The common principle of risk to the human species is not applied consistently. The differences between IAEA recommendations and local regulatory conditions are compared, and the use of exemption levels as clearance levels is considered. A case study on management of mine tailings is presented with special focus on the use of clearance levels. In all areas of review the interpretation of regulation is subject to confusion resulting from inconsistencies which can distort free market economics. (author).

Energy Technology Data Exchange (ETDEWEB)

The use of hypothesis which assumes a dose / harmful effect relationship without a limit allows the calculation of risks attributable to doses too small to produce detectable, harmful biological effects. The daughter product of this hypothesis is ALARA concept which requires that the dose received is kept as low as reasonably achievable. This concept of prudent avoidance is generally accepted by international radiation protection organisations and universally applied by radiation health professionals. The acceptance of a hypothesis which assumes that a single nuclear event can cause carcinogenesis, has generated levels of anxiety which may have resulted in significant detriment to those possibly exposed to ionising radiation. The anxiety generated may have caused more detriment and a higher death rate than the worst case ` theoretical` value calculated using the Linear or Quadratic Linear Hypothesis. ...

Science.gov (United States)

The system of the early forecast of radiation hazardous fluxes of solar cosmic rays in space on the basis of the real time neutron monitors data obtained by the NMDB (Neutron Monitor Data Base) network is created. The forecast system is based on a short cut technique of definition of a spectrum of solar protons from the data of the limited number of neutron monitor stations and with a simplified procedure of accounts. It is shown that the results of computations of solar proton spectra with the short-cut technique little differ from spectra obtained with a complete technique at energies less than 5 GeV. Thus the good agreement between derived from the neutron monitor data intensities of solar protons in an energy range of hundreds MeV with the data of direct measurements of solar protons at GOES-11 spacecraft is observed. The maximum of increase on neutron monitors outstrips on several hours (2-10) an appropriate maximum of radiation-dangerous ...

International Nuclear Information System (INIS)

To respond to an increase of social problems concerning orphan sources in Japan, a working group was formed in the Japan Health Physics Society. In this working group, we investigated how to prevent acute radiation hazard or social panic regarding orphan sources in scrap metal and detection system for orphan sources brought into scrap yards before recycle. For detection system in a scrap yard we conducted an experiment on detectability of monitoring instrument using a radiation source mixed in scrap metal on a truck. The result showed that it was not easy to detect even a high-level source if it was shielded by scrap metal. We also estimated detection limits for radioactive materials in scrap metal by calculation that was validated with experimental data. We summarized present status about orphan sources in Japan and proposed a categorization of orphan sources according to dose rates to deal with unknown sources in a scrap ...

International Nuclear Information System (INIS)

... organizations irradiation radiation doses radiation effects RADIATIONS.

International Nuclear Information System (INIS)

... halogenation ionizing radiations kinetics radiations reaction kinetics

Energy Technology Data Exchange (ETDEWEB)

This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents results of a laboratory and field study of naphthenic acid corrosion and the development of an effective chemical inhibitor for this type of corrosive attack. In the laboratory corrosion test, which involved 20 hour weight loss measurements in high flash solvent with a total acid number (TAN) of 16 mg KOH/gm at a temperature of 600 F (316 C), blank corrosion rates averaged 140 to 150 mpy (3.56 to 3.81 mm/y). Inhibited rates averaged about 10 to 12 mpy (0.254 to 0.305 mm/y). The field test was carried out on a heavy vacuum gas oil (HVGO) stream at 550 F (288 C) . Blanks varied from a high of 425 mpy (10.79 mm/y) for a 24 hour test to a low of about 100 mpy (2.54 mm/y) for a 150 hour test. Both electrical resistance (ER) probes and weight loss coupons showed corrosion rates below 5 mpy (0.127 mm/y) as long as they were adequately passivated. Passivation consisted of exposing the coupons to a high inhibitor dosage for a ...

International Nuclear Information System (INIS)

Purpose/Objective: The role of programmed cell death (apoptosis) as a cellular response to cancer therapy such as radiation or chemotherapy is the subject of much study, and manipulation of the apoptotic response in tumor cells may be valuable in the treatment of a variety of cancers. Both p53 dependent and independent apoptotic pathways have been identified; p53 is mutated in at least 50 % of human cancers and a majority of radiation resistant tumors contain p53 mutations. This study is designed to examine the induction of programmed cell death in a human colon carcinoma cell line that possesses two mutated p53 alleles. Ionizing radiation alone, or in combination with the chemotherapeutic drug 5-fluorouracil (5-FU), were used to elicit the apoptotic response. This study will focus on whether these treatments can induce a significant apoptotic response in cells that have mutated p53 alleles. Materials and Methods: HT-29 ...

Energy Technology Data Exchange (ETDEWEB)

The dosimetry for radiotherapy involving neutrons is very complicated, owing to the complexity of secondary radiation components, whose contributions to the total absorbed dose have to be discriminated, owing to the different radiobiological effects. In order to separate thermal neutrons and photons, LiF dosimeters are mostly utilized. containing different percentage of Li, like as TLD-700, TLD-100 and TLD-600, but many problems arise. In the response of TLD-700 exposed to neutron-gamma mixed fields with high neutron flux, the contribution of thermal neutrons to the Tl emission is high. Moreover. TLD-100 and TLD-600 may undergo radiation damage, and great care has to be taken in order to obtain reliable results. Other TLDs showing lower sensitivity to neutrons are proposed and experimented for such high-flux neutron fields. The faced problems and various proposed solutions are here described. (Author)

CERN Document Server

We present high-resolution hydrodynamical simulations of the degree and direction of polarisation imprinted on the CMB by the Sunyaev-Zel'dovich effect in the the line of sight to massive galaxy clusters. We focus on two contributions which contribute most of the induced CMB polarisation in addition to the intrinsic CMB quadrupole: the radiation quadrupole seen by electrons due to their own velocity in the plane normal to the line of sight, and the radiation quadrupole due to the thermal Sunyaev-Zel'dovich effect, which is generated by a previous scattering elsewhere in the cores of the local and nearby clusters. We show that inside the virial radius of a massive cluster, this latter effect, although being second order in the optical depth, can reach the level of the former effect. These two effects can, respectively, constrain the projected tangential velocity and inner density profile of the gas, if they can be separated ...

International Nuclear Information System (INIS)

Results of experimental investigation into radiation electromagnetic effect (REM) in samples of germanium crystals under approximately 40 MeV #alpha#-particle irradiation in a cyclotron are presented. A high level of excitation, volumetric character of generation of non-equilibrium carriers and formation of defects as well as the form of their spatial distribution are shown to result in some peculiarities of the EMF of the REM effect on the particle flux, fluence and sample parameters. Agreement of theoretical calculations, conducted with account of specificity of #alpha#-particle interaction with a crystal, and experimental data is obtained. It is revealed that the REM effect can be applied in obtaining data on spatial distribution of non-equilibrium carrier concentrations along the particle trajectory in the crystal.

International Nuclear Information System (INIS)

A wood-polymer composite has been produced by impregnating the wood with the monomer and subsequently polymerizing it by exposure to a gamma radiation source. To compare the improvement in creep deformation of the wood due to the polymer impregnation, a nonlinear Norton-Bailey isothermal mathematical function has been used to model the bending creep deformation of the wood-polymer composites. Results show that the impregnation significantly improves the creep resistance of the wood. The maximum creep resistance is obtained when the amount of polymer impregnation exceeds about 30%. An interfacial interaction between the wood cell wall and the polymer could explain the creep deformation improvement, as well as the maximum impregnation level beyond which little improvement occurs. The results indicate that polymer impregnation is a viable method for improving the poor creep properties of wood. (author).

Energy Technology Data Exchange (ETDEWEB)

We construct the time-dependent radiation model for the pulsar wind nebulae (PWNe), assuming that leptons are accelerated in resonant scattering with heavy nuclei, which are injected into the nebula by the pulsar. The equilibrium spectra of these particles inside the nebula are calculated taking into account their radiation and adiabatic energy losses. The spectra of {gamma}-rays produced by these particles are compared with the observations of the PWNe emitting TeV {gamma}-rays and predictions are made for the expected {gamma}-ray fluxes from other PWNe. Expected neutrino fluxes and neutrino event rates in a 1 km{sup 2} neutrino detector from these nebulae are also calculated. It is concluded that only the Crab Nebula can produce a detectable neutrino event rate in the 1 km{sup 2} neutrino detector. Other PWNe can emit TeV {gamma}-rays on the level of a few percent of that observed from the Crab Nebula.

International Nuclear Information System (INIS)

This paper reviews various techniques to harden Charged Coupled Device (CCD) sensors and the results after irradiation of three Thomson n buried channel CCDs having a different degree of hardening. It describes the major irradiation effects on CCD performances and it makes a comparison of the results between the different hardening levels. It shows good results on dark voltage after ionizing radiation for TH 7863M device hardened both by design and by operating conditions (MPP mode) with respect to the standard device TH 7863A. The irradiations were performed with "6"0Co or X-ray (10 keV) sources on devices in operating mode. (author). 3 refs., 8 figs.

International Nuclear Information System (INIS)

It is essential that alumina used for manufacturing electronic devices should contain an extremely low level of alpha-radiation. The principal source of alpha-radiation in alumina is uranium, a minor source being thorium. Uranium in bauxite dissolves into the liquor in the digestion process and is fixed to the red mud as the desilication reaction progresses. A part of uranium remaining in the liquor precipitates together with aluminum hydroxide in the precipitation process. The uranium content of aluminum hydroxide becomes lower as the precipitation velocity per unit surface area of the seed becomes slower. Organic matters in the Bayer liquor has an extremely significant impact on the uranium content of aluminum hydroxide. Aluminum hydroxide free of uranium is obtainable from the liquor that does not contain organic matters.

International Nuclear Information System (INIS)

The process of mouse skin tumor formation is subdivided into three operational stages. These stages include initiation, promotion and progression. Ionizing radiation has been found to be a weak initiating agent in the production of malignant squamous cell carcinomas, a complete carcinogen and an agent effective in causing tumor progression. Four skin tumor histologies have been seen with ionizing radiation: benign papillomas, squamous (SCC) and basal (BCC) cell carcinomas and fibrosarcomas. Distinct non-ras transforming genes have been detected in radiation initiated SCCs. A benign papilloma cell line (308) was used as a model system to study ionizing radiation induced progression. A variant 308 cell line (308 10 Gy 5) derived by irradiation of the parental 308 cell has been characterized. The 308 10 Gy 5 cells unlike the parental 308 cells from malignant tumors in athymic nude mice upon subcutaneous ...

CERN Document Server

Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO sub 2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of ...

Energy Technology Data Exchange (ETDEWEB)

Recent studies have shown that there is a wide variety of approaches to education and training of the Qualified Expert across the European Union. National education and training programmes show often large differences in content, duration, level, the introduction of practical work, etc. As they stand, such differences are a barrier to the mutual recognition of the Qualified Expert status and, in part, are contributing to a perceived shortage in expertise in radiation protection and safety. The overall aim of ENETRAP is to determine mechanisms that in the longer term will facilitate better integration of education and training activities (with a view to mutual recognition across the European Union) and to ensure the ongoing provision of the necessary competence and expertise at the level of the Qualified Expert. The ENETRAP project is a 6FP coordination action. It started in April 2005 and runs over a period of 24 months. ...

International Nuclear Information System (INIS)

The results of radon concentration measurements inside of the Gabriel caves of Mexico, during three consecutive two-month periods covering almost three seasons, are reported in the present work. The radio-ecological importance of this site is related to the radon and its concentration-dynamic behavior in the cave. Further interest in radiation safety motivated this initiative since routine biological field work is done, with people spending long periods of time there. CR-39 passive nuclear track detector was chosen for this survey. Radon concentration levels decrease during the rainy season and show different values depending on the ventilation and geometeorological structure. Measured values range between 956 and 4931Bqm-3, an indication that radon doses may exceed the allowed values for workers. This project is part of a larger study of indoor radon alpha emitters in Mexican caves.

Energy Technology Data Exchange (ETDEWEB)

The strongly localized one-electron (D{sup 0}) and two-electron (D{sup -}) donor states are considered with the lattice deformation around the donor center taken into account. For GaAs, donor energy levels have been calculated as functions of the hydrostatic pressure. The calculated energy positions and pressure coefficients agree with the experimental data. It is shown that the interaction with phonons reduces the probability of radiative transitions between the states of different localization and leads to the metastability of shallow-level donor states with respect to the D{sup -} state in GaAs and both the states (D{sup 0} and D{sup -}) in CdF{sub 2}. (author) 7 refs, 1 fig

Energy Technology Data Exchange (ETDEWEB)

A strategy for the management of the disposal of low-level radioactive wastes into coastal zones and ocean waters has developed over the past three decades. While there has been a substantial increase in the number of international and required agreements there has also been a concomitant improvement in our understanding of the ocean and the processes at work within it. This has allowed more rigorous and reliable assessments to be made of the radiological consequences. With the continued development of basic guidelines of radiological protection by the International Commission on Radiological Protection (ICRP) methodologies have been formulated to derive the fundamental scientific requirement - the relationship between disposal or release rate to the ocean and the resultant radiation dose to exposed human populations.

Energy Technology Data Exchange (ETDEWEB)

Environmental data were collected for most environmental media including air, Columbia River water, external radiation, foodstuffs (milk, beef, eggs, poultry, and produce) and wildlife (deer, fish, and game birds), as well as soil and vegetation samples. In general, offsite levels of radionuclides attributable to Hanford operations during 1979 were indistinguishable from background levels. The data are summarized in the following highlights. Air quality measurements of NO/sub 2/ in the vicinity of the Hanford Site and releases of SO/sub 2/ onsite were well within the applicable federal and state standards. Particulate air concentrations exceed the standards primarily because of agricultural activities in the area. Discharges of waste water from Hanford facilities in the Columbia River under the National Pollution Discharge Elimination System (NPDES) permit were all within the parameter limits on the permit.

International Nuclear Information System (INIS)

Ionizing radiations that differ in number, size, and distribution of energy deposition events might be expected to cause different effects for the same absorbed dose. Furthermore, microdosimetry calculations suggest that large variations in biological effectiveness might be expected for internally deposited alpha-emitting radionuclides for the same absorbed dose, depending upon the specific activity and spatial distribution of the sources in tissue. The study described in this article was designed to demonstrate these phenomena in vitro. Cultured Chinese hamster ovary (CHO-K1 BH4) cells were exposed in vitro to inert, insoluble ceramic microspheres in zirconium dioxide labeled with "2"3"9Pu. The average exit energy of the 5.15 MeV alpha particle was calculated to be 4.3 MeV. Exposure times varied from four to seven hours to achieve the desired dose level.

International Nuclear Information System (INIS)

The interest for medicinal plants has raised again in the last decades, after overcoming a declination period caused by the advances in the researches and development of the synthetic drugs industries. This growing interest has been stimulated mainly by searching cheap and accessible alternative therapies. However, in order to have natural products based treatment in an efficient and safety way, it is necessary to guarantee the plant authenticity, finding adulterations and to assure a low level of microbiological contaminations to avoid damages to consumer's health. The decontamination method should be chosen for eliminating or reduce the microorganisms level without loss of the plant active constituents that would destroy its therapeutic action. At the present work, the possibility of using #gamma# and X electromagnetic radiations to sterilize a Brazilian medicinal plant (Maytenus aquifolium Martius, Celastraceae), which ...

International Nuclear Information System (INIS)

The purpose of the study was to optimise the technique employed for AP shoulder and lateral cervical spine examinations following an investigation into image quality, based on clinical assessment, and effective dose, calculated from patient entrance surface dose measurements. A study was therefore conducted in an attempt to determine whether the increased radiation dose to the patient following the introduction of an anti-scatter grid was justified by the level of improvement in image quality. The study, involving 100 patients, was able to demonstrate that the increase in radiation dose to the patient when using an anti-scatter grid for AP shoulder examinations is not justified by the improved image quality. A poor level of inter-rater reliability between the consultants scoring the lateral cervical spine images prevented a firm conclusion from being reached. The fact that all images were of diagnostic ...

International Nuclear Information System (INIS)

This paper reports regulation of hypoxia inducible factor-1 ? (HIF-1 ?)in hepatoma cells by irradiation. Cobalt chloride (CoCl2), a chemical mimic agent for hypoxia research, was utilized to induce the stable expression of HIF-1 ? in HepG2 cells. The HepG2 cells were irradiated to different doses to observe the changes of HIF-1 ?. The level of intracellular reactive oxygen species (ROS) was assayed by fluorescent microscope and flow cytometry (FCM). The results showed that there were obvious changes in expression of HIF-1 ? after HepG2 cells exposed to radiation, and the changes were positively related with the irradiation dose from 1 Gy to 5 Gy. Moreover, contents of incellular ROS were negatively correlated with above levels of HIF-1 ? from 1 Gy to 3 Gy. The results indicate that irradiation may enhance hypoxic cells HIF-1 ?, and the reduction of intracellular ROS can contribute to the regulation of ionizing ...

International Nuclear Information System (INIS)

Seizures are a frequent sequela of impaired brain development and can be expected to affect more children with radiation-related brain damage than children without such damage. This report deals with the incidence and type of seizures among survivors prenatally exposed to the atomic bombing of Hiroshima and Nagasaki, and their association with specific stages of prenatal development at the time of irradiation. Fetal radiation dose was assumed to be equal to the dose to the maternal uterus. Seizures here include all references in the clinical record to seizure, epilepsy, or convulsion. Histories of seizures were obtained at biennial routine clinical examinations starting at about the age of 2 years. These clinical records were used to classify seizures as febrile or unprovoked (without precipitating cause). No seizures were ascertained among subjects exposed 0-7 weeks after fertilization at doses higher than 0.10 Gy. The incidence of seizures ...

CERN Document Server

We compare the predictions of four different algorithms for the distribution of ionized gas during the Epoch of Reionization. These algorithms are all used to run a 100 Mpc/h simulation of reionization with the same initial conditions. Two of the algorithms are state-of-the-art ray-tracing radiative transfer codes that use disparate methods to calculate the ionization history. The other two algorithms are fast but more approximate schemes based on iterative application of a smoothing filter to the underlying source and density fields. We compare these algorithms' resulting ionization and 21 cm fields using several different statistical measures. The two radiative transfer schemes are in excellent agreement with each other (with the cross-correlation coefficient of the ionization fields >0.8 for k 0.6 for k < 1 h/Mpc). When used to predict the 21cm power spectrum at different times during reionization, all ionization algorithms agree with ...

International Nuclear Information System (INIS)

Various remedial measures have been tried to lower radon levels in buildings in Uranium City. The methods used are source material removal, passive ventilation of crawl spaces, sub-floor ventilation, complete epoxy coating of the entire basement, sealants for floor-wall joints and cracks in basements, electrostatic precipitators, mechanical ventilation, and sealing and grouting concrete block plenums in basement walls. The type and condition of structures encountered in Uranium City as well as the relative isolation of the town indicate that mechanical ventilation is the most long-term cost-effective method.

International Nuclear Information System (INIS)

The 2nd periodical inspection was carried out on the asphalt solidification facility and the incinerator in Unit 2 of the Sendai Nuclear Power Station from November 5 to 28, 1985. Inspection was made in radiation control facility and disposal facility. By external appearance, disassembly, function and performance tests there were observed no abnormalities. The personnel exposure doses during the inspection were below the permissible level. In the inspection, improvement etc. works were not done. (Mori, K.).

International Nuclear Information System (INIS)

A wood/polymer composite was produced by impregnating Ramin wood with methyl methacrylate monomer and subsequently polymerizing it by gamma irradiation. To assess the improvement in compression strength of the wood caused by the polymer impregnation, a microbuckling compression failure mechanism was used to model the compression failure of the composite. Such a mechanism was found to predict a linear relationship between the compression strength and the percentage polymer impregnation (by weight). Uniaxial compression test results at 45(#+-#5)% and 90(#+-#5)% relative humidity levels, after being statistically analysed, showed that such a linear relationship was valid for up to 100% polymer impregnation. (author).

Energy Technology Data Exchange (ETDEWEB)

As a part of the program at the Lawrence Livermore National Laboratory (LLNL) in induction-linac free-electron laser (IFEL) research, the authors are conducting a variety of activities addressing the unique requirements imposed on IFEL wiggler systems. They are actively developing improved DC iron-core electromagnetic wiggler designs to attain higher peak fields, greater tunability, and lower random error levels. They are pursuing specialized control systems, such as magnetic-field and beam-position controllers, which can relax requirements on the wiggler itself. They are also pursuing basic studies to establish the effect of radiation on permanent magnets.

Energy Technology Data Exchange (ETDEWEB)

These studies have addressed firstly the effect of single small doses of x-ray upon murine hematopoietic stem cells to obtain a better estimate of the D/sub q/. It is small, of the order of 20 rads. Secondly, a dose fractionation schedule tht does not kill or perturb the kinetics of hemopoietic cell proliferation was sought in order to investigate the leukemogenic potential of low level radiation upon an unperturbed hemopoietic system. The studies reported herein show tht 1.25 rads every other day decrease the CFU-S content of bone marrow by the time 40 rads are accumulated. Studies on the effect of 0.5, 1.0, 2.0, and 3.0 rads 3 times per week are under way. Two rads 3 times per week produced a modest decrease in CFU-S content of bone marrow after an accumulation of 68 rads. With 3.0 rads 3 times per week an accumulation of 102 rads produces a significant decrease in CFU-S content of bone marrow. Dose fractionation at 0.5 and 1.0 rad 3 times ...

International Nuclear Information System (INIS)

Since 1945, more than 1.8 x 10"2"1 Bq of artificial radionuclides have been released into the atmosphere. Approximately 2.04 x 10"1"8B, i.e. approx. 0.11%, are the result of accidents at nuclear industrial facilities. This percentage is causing increased interest among researchers. This is due to the fact that in the wake of accidental release radionuclides become distributed unevenly across the Earth's surface, and the associated exposures, fluctuating from background level to several grays, an induce both stochastic and deterministic effects in the irradiated population. A comparative analysis of the medical consequences of the twentieth century's most serious nuclear events, namely the authorized dumping of high level radioactive waste into the river Techa in 1950, the explosion of a storage tank containing long lived radioactive waste in the Southern Urals in 1957, the fire at Sellafield in 1957 and the accident at the Chernobyl nuclear ...

Energy Technology Data Exchange (ETDEWEB)

The results of a scoping study of onsite radiation exposures which could take place in each of three types of postulated reactor accidents are presented. The accident types are (1) a fuel handling accident at a Mark III BWR; an interfacing system LOCA or V sequence at a PWR; and and Anticipated Transient Without Scram (ATWS) at a Mark I BWR. Both external and internal dose pathways are considered. The results of the study indicate the prohibitively high radiation doses could be received in some plant areas if personnel were to remain there. However, times of the order of a few minutes to a few hours, depending on the type of accident, would be available before life-threatening doses would be accumulated assuming that the provided full face respiratory protection equipment were used promptly. Special attention was given radiation doses possibly received by control room personnel for several control room air in-leakage ...

International Nuclear Information System (INIS)

Apoptosis, or programmed cell death (PCD), is a fundamental process that protects organismal integrity. In earlier work, we demonstrated that over-expression of either of two anti-apoptotic members of the BCL-2 family (BCL-2 or BCL-X L could elevate the frequency of radiation-induced mutations at the autosomal TK1 locus in human TK6 lymphoblasts that express wild-type TP53. Ectopic expression of BCL-X L also elevated the frequencies of double-strand break-induced gene conversion. The purpose of this study is to determine if BCL-2 family proteins promote radiation mutagenesis indirectly through their suppression of PCD, or whether the 'pro-mutagenic' function of these proteins can be separated from their anti-apoptotic function. We developed stable transfectants of TK6 cells that express a mutated form of BCL-X L with a single amino acid substitution in the BH1 domain that is known to interfere with the ability to suppress PCD (BCL-X L ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Science.gov (United States)

... radiation during clinical therapy and exposures due to radiation accidents or attacks, in which the doses are uncontrolled ... only be used off-label in victims of radiation accidents or attacks. The idea...

Energy Technology Data Exchange (ETDEWEB)

Material testing of SPF-sheet is usually done with coupon hot tensile testing. The optimum range of strain rates is determined with stepped strain tests. To overcome the problem of very few available testing facilities and time consuming and costly procedure, cone cup testing has been developed since long. This test can be generated directly in the workshop, no machining of samples is necessary and it is very much related to the real SPF-process. The analysis of suitable temperature and strain rate is done by simple measurement of resulting cone height. This paper describes a unique and novel variant of the above mentioned baseline design. It provides on-line data of the actual status of the cone cup forming resulting from the applied, constant pressure. Strain rate variations as a result from texture or from the alloy-related behaviour is detectable. Thinning and ''hardening'' behaviour of different alloys up to maximum failure ...

International Nuclear Information System (INIS)

Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBqxm"-"3 (2.38 nCi x l"-"1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF_2-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy x h"-"1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring "2"3"8U, "2"3"2Th and "4"0K radionuclides were carried out in various speleothems found at different sites in the cave. (author)

Energy Technology Data Exchange (ETDEWEB)

The thermal performance of an automotive radiator plays an important role in the performance of an automobile's cooling system and all other associated systems. For a number of years, this component has been given little attention with very little changing in its manufacturing cost, operation and geometry. As opposed to the old tubular heat exchanger configurations used in automotive radiators, plate heat exchangers currently form the backbone of today's process industry with their advanced performance reaching levels the designers of tubular heat exchangers can only dream of. The aluminium roll-bonding technique widely used in manufacturing the cooling compartments for domestic refrigeration units is one of the cheapest methods for heat exchanger manufacturing. Using this technique, it is possible to manufacture a wide range of heat exchanger configurations that can help augment heat transfer whilst ...

International Nuclear Information System (INIS)

GRR-1 is a 5MW open pool type research reactor with MTR-type fuel elements cooled and moderated by light water with beryllium reflectors at the two opposing sides of the core. A graphite thermal neutron column is adjusted to one side of the core. Six radial horizontal beam tubes are available, of which three contain in-pile collimators for neutron scattering instruments. The reactor is currently out of operation for inspection and refurbishment purposes. The core has been dismantled and the fuel elements are stored in the used fuel storage tank. The GRR-1 inspection and refurbishment plan involves inspection and eventually replacement of the reactor's primary cooling circuit. The health physics procedures to be implemented during inspection of the main water outlet are divided in three stages: a) pool dose rate survey from pool top, b) pool drainage by decreasing water level in steps and c) inspection of the water main outlet. urpose of the present work is the ...

International Nuclear Information System (INIS)

... radiation effects human populations low dose irradiation neoplasms radiation

International Nuclear Information System (INIS)

... defects doped materials germanium infrared radiation monocrystals neutron

International Nuclear Information System (INIS)

... pathological changes patients radiation protection radiotherapy diseases

International Nuclear Information System (INIS)

... compounds polymers polyolefins polyvinyls radiation effects SYNTHESIS.

CERN Document Server

Compact Proton and Carbon Ion Synchrotrons for Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Systematics of neutron capture radiative width were studied in the target element range from Th to Cm. Reduced radiative widths were analyzed with a simple radiative width formula based on E1 transition. Average radiative width is presented with the standard deviation of 15%. (author)

International Nuclear Information System (INIS)

Full text: In the upper layers of the Earth's atmosphere, molecular nitrogen absorbs the extreme ultraviolet (XUV) solar radiation. The absorption is associated with dipole-allowed excitation of states of singlet ungerade symmetry ("1#SIGMA#"+_u and "1#PI#_u), which are known to undergo predissociation due to coupling with a mainfold of "1#PI#_u states. We determined new N_2 isotopic lifetimes of many "1#SIGMA#"+_u and "1#PI#_u states via line broadening measurements in the frequency domain. Ultrahigh resolution XUV + UV ionization spectra were recorded (bandwidth #approx# 250 MHz, resolving power 10"7), from which the natural linewidth, i.e. lifetime, was determined. These lifetimes provide new information about the predissociation of the singlet ungerade states in N_2. Tunable narrowband XUV radiation was produced by successively pulsed amplification of cw dye laser radiation, frequency doubling the pulsed visible laser ...

International Nuclear Information System (INIS)

As a part of the compatibility analysis of DUPIC fuel in CANDU reactors, the radiation physics calculations have been performed for the CANDU primary shielding system, thermal shield, radiation damage, transportation cask and storage. At first, the primary shield system was assessed for the DUPIC fuel core, which has shown that the dose rates and heat deposition rates through the primary shield of the DUPIC fuel core are not much different from those of natural uranium core because the power levels on the core periphery are similar for both cores. Secondly, the radiation effects on the critical components and the themal shields were assessed when the DUPIC fuel is loaded in CANDU reactors. Compared with the displacement per atom (DPA) of the critical component for natural uranium core, that for the DUPIC fuel core was increased by -30% for the innermost groove and the weld points and by -10% for the ...

Energy Technology Data Exchange (ETDEWEB)

This paper is dedicated to the treatment of sludge occurring in frame of the Egyptian produced from oil and gas production. The activity levels of three radium isotopes: Ra-226 (of U-series), Ra-228 and Ra-224 (of Th-series) in the solid TENORM waste (sludge) were first evaluated and followed by a sequential treatment for all radium species (fractions) presented in TENORM. The sequential treatment was carried out based on two approaches 'A' and 'B' using different chemical solutions. The results obtained indicate that the activity levels of all radium isotopes (Ra-226, Ra-228 and Ra-224) of the environmental interest in the TENORM waste sludge were elevated with regard to exemption levels established by IAEA [International Atomic Energy Agency (IAEA), International basic safety standards for the protection against ionizing radiation and for the safety of ...

International Nuclear Information System (INIS)

Background and purpose: A diagnosis of malignancy and its treatment is a very stressful time for patients and their families. This study was conducted to determine the impact of more intensive written information on patients' anxiety levels. The secondary aim was to determine the impact of this information on patients' satisfaction levels. Materials and methods: This prospective randomized trial consisted of patients with a pathological diagnosis of cancer having radical radiotherapy (RT). Patients were randomized to receive the more intensive information (including written information and a telephone call from the research nurse) or not to receive the more intensive information at the time of their initial consultation with the radiation oncologist. Study questionnaires measuring anxiety (STAI form) were completed prior to their first consultation (baseline) at the time of simulation (pre-RT) and at the completion of ...

Energy Technology Data Exchange (ETDEWEB)

Ovarian function was evaluated in 11 women 16 to 43 years of age at treatment who received doxorubicin, cyclophosphamide, and high doses of methotrexate with or without radiotherapy in adjuvant therapy of soft tissue sarcoma. Five women (16-33 yr old) who received chemotherapy alone or combined with radiotherapy only at sites distant from the ovaries (chest wall, thigh, and leg) had minimal menstrual irregularities or temporary cessation of menses during therapy; cyclic menses returned promptly after therapy. Gonadotropin levels (expressed as means +/- SD) (follicle-stimulating hormone (FSH), 10 +/- 15 mlU/ml; luteinizing hormone (LH), 10 +/- 4 mlU/ml) and 17 ..beta..-estradiol (E/sub 2/) levels (means +/- SD, 208 +/- 147 pg/ml) were normal. By contrast, 4 older women (ages 36-43 yr) who received similar treatment developd persistent amenorrhea with postmenopausal levels of gonadotropin (FSH, 109 +/- 29 mlU/ml; LH, 72 +/- ...

International Nuclear Information System (INIS)

A 450 MeV Synchrotron Radiation Source, Indus-1 is being constructed at Centre for Advanced Technology at Indore in central India. This paper narrates our experience in construction and alignment of synchrotron machines which was first of its kind for most of us. Careful design, planning and execution of the work yielded modest results so that alignment accuracies between 0.1 to 0.3 mm could be achieved (in booster synchrotron) and, which have proved to be adequate up till now. The building of the SRS complex was constructed such that machine rings have their foundations isolated from rest of the building. A number of 100 x 150 mm size steel plates were embedded in the concrete of floor and walls to serve as base for reference surveying marks which were established later. The pre-injector and booster ring are enclosed in a radiation shielding zone with separate ventilation system. Dipoles, quadrupoles and a few sextupoles were fiducialised ...

International Nuclear Information System (INIS)

We propose to investigate the spontaneous emission of radiation arising out of the interaction of a relativistic electron beam with a metallic grating (the Smith-Purcell effect). The work will concentrate, primarily, in the 50-120 #mu#m part of the infrared spectrum and will be an extension of the work begun by the Oxford-Dartmouth-Essex collaboration; one of the early objectives of the project will be to develop a quantitative understanding of the power spectrum of the emitted radiation over a wide range of emission angles. In particular, the limits of relativistic peaking of forward directed emission will be investigated. The electron beam will be produced by laser irradiation of a metallic cathode in the terminal of a small Van de Graff accelerator located in the Technische Universitaet, Muenchen. Beam energies will be in the range of 2 - 4 MeV. Initial tests on photoproduction of electrons have yielded 10 mA pulses with a width of about 20 ...

Energy Technology Data Exchange (ETDEWEB)

A workshop on radioactivity in coal use was held on September 15 through 17, 1981, under the auspices of the US Department of Energy, Office of Environmental Programs, and the Los Alamos National Laboratory. The purpose of the workshop was to identify research issues associated with radioactivity resulting from the use of coal for electric power generation. The concensus of the 10 scientists participating in the workshop was that a moderate to strong need exists for research in solubility of fly ash in different fluids and for determination of radioactivity in construction materials. Several additional research issues were identified but were given a lower priority. Summaries of each presentation are included. Titles are: some effects of coal combustion on the radiation environment; radionuclides in western coal at Mound; low-level radiation in coals utilized and ashes produced at New York State electric utilities; ...

International Nuclear Information System (INIS)

Radiation defects produced by helium implantation were used to shape profiles of palladium (Pd) and platinum (Pt) atoms in-diffusing (for 20 min at temperatures 600-800 deg. C) either from surface silicide (Pd_2Si, PtSi) or implanted layers. Results show that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centers - the acceptor level of substitutional Pd (E _c - 0.22 eV) or Pt (E _c - 0.23 eV). While optimum conditions for Pt in-diffusion are about 700 deg. C, Pd gives the best results already at lower temperatures (600 deg. C) where it also exhibits higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by Pd and Pt, exhibited similar trade-off between the static and ...

Energy Technology Data Exchange (ETDEWEB)

Bone marrow is one of the most radiosensitive organs. Irradiation causes a marked decrease in the total number of hematopoietic cells in the bone marrow. The reticular meshwork structure of marrow stromal cells, however, is relatively resistant to irradiation. Unimpaired stromal cell structure has been thought to be a prerequisite for the repopulation of hematopoietic cells during recovery from the effects of irradiation. The reticular framework is maintained by cell adhesion apparatuses such as gap junctions. The in vitro radiobiologic survival values of a cloned stromal cell line, H-1/A, were studied (n = 1.8, D0 = 138 cGy). Radiation doses of up to 4000 cGy had no detectable effects on the production of colony-stimulating factor 1. H-1/A cells communicate with each other via gap junctions as determined by the sensitive dye-transfer method. Gap-junctional communication between H-1/A cells was resistant to different levels of irradiation (500 ...

Science.gov (United States)

Environmental monitoring data were collected at and around the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada Test Site. These data are associated with radiation exposure, air, groundwater, meteorology, vadose zone, subsidence, and biota. This report summarizes the 2006 environmental data to provide an overall evaluation of RWMS performance and to support environmental compliance and performance assessment (PA) activities. Some of these data (e.g., radiation exposure, air, and groundwater) are presented in other reports (U.S. Department of Energy, 2006; Warren and Grossman, 2007; National Security Technologies, LLC, 2007). Direct radiation monitoring data indicate that exposure levels around the RWMSs are at or below background levels. Air monitoring data at the Area 3 and Area 5 RWMSs indicate that tritium concentrations are slightly above background ...

International Nuclear Information System (INIS)

Radiation induced polymerization of methylmethacrylate and copolymerization of styrene-acrylonitrile mixture in mamrase Carpinus betulus was carried out by means of #gamma#-ray, under different moisture levels and additives. Under all conditions the degree of polymerization was as high as 60%. No pronounced differences were observed in the kinetics of the polymerization of MMA either with moisture content of wood nor with kind and amount of additives. At high moisture (80% RH) content the dimensional stability of wood-PMMA was increased four fold as compared with untreated wood. The hardness increased about 100% for a weight conversion of monomer of about 30 to 40%. Hardness of this wood-polymer composite is comparable to that of the best noble woods in the world. (author).

International Nuclear Information System (INIS)

A scheme of evaluating a generalized three-photon excitation cross section #sigma#/sub (3)/ in neutral atomic argon at 3144.67 A is outlined. Three photons at this wavelength can excite the neutral argon atoms from the ground 3p"6 "1S_0 state to the 3p"54s'[1/2]_1"0 state. The fourth photon will ionize the argon atoms. Assuming linear polarization of the incident laser radiation, contributions from several channels in various energy-level schemes are summed in the evaluation of the transition probability. For a laser linewidth of #DELTA##lambda#/sub L/ = 1 A, our maximum numerical value of the computed result for the three-photon excitation cross section is #sigma#/sub (3)/ = 1.414 x 10/sup -80/ cm"6 s"2. .AE.

Energy Technology Data Exchange (ETDEWEB)

Several nuclear power plants are operating in Wolsung area, a south-east coastland of Korea. In addition, a medium-level radioactive waste repository is under construction there. If radionuclides are released from these facilities, food crops could be radioactively contaminated, leading to human exposure to internal radiations via food consumption. There are a number of rice fields around the Wolsung nuclear sites. However, almost nothing has yet been reported on the transfer of radionuclides to rice plants from Wolsung soils. In this study, {sup 85}Sr and {sup 137}Cs transfer factors (TFs) were measured for the rice in three paddy soils collected around the Wolsung nuclear sites.

Energy Technology Data Exchange (ETDEWEB)

Results are presented from a numerical model of the steady-state energy transfer in molten-salt-in-tube solar cavity receivers that includes convective energy transfer at a local (spatially resolved) level. Molten salt energy absorption and gray radiative transfer between all cavity surfaces are also included. This model is applied to the Molten Salt Subsystem Component Test Experiment (MSS/CTE) cavity receiver. Results for this receiver indicate the global (entire cavity) receiver thermal efficiency is invariant within a few percent to most parameters investigated, although front surface temperatures of the nonabsorbing walls vary considerably, and are particularly sensitive to the type of convective submodel used. Absorption efficiencies indicate the effects of the cavity enclosure environment. For all conditions investigated, tube inner wall temperatures remain under 855 K, ensuring that the salt remains chemically stable.

Wastenet

... Project Details Title: Influence of increasing droplet concentrations on properties of stratocumulus clouds and climate Supervisor: Dr Alan Gadian Funded by: Engineering and Physical Sciences Research Council (EPSRC) Start date: October 2006 My project involves use of the UK Met Office Unified Model (UM) to calculate the global effect of modifying stratocumulus droplet concentrations on the earth's radiation balance, as well as use of ... Publications Latham, J; Rasch, P; Chen, CC; Kettles, L; Gadian, A; Gettelman, A; Morrison, H; Bower, K; Choularton, T (2008) Global temperature stabilization via controlled albedo enhancement of low-level maritime clouds, Philos. Trans. Roy. Soc. A, 366(1882), pp3969-3987. doi:10.1098/rsta.2008.0137 Current Students | Internal ...

International Nuclear Information System (INIS)

A brief survey is presented of the methods of preparation and of the applications of radiopharmaceuticals labelled with short-lived positron radionuclides "1"1C, "1"8F, "1"3N and "1"5O which, thanks to their energy level schemes, short half-life and the 511 keV photon radiation energy are almost ideal tracers in modern nuclear medicine and pharmacology. In conjunction with computerized tomography, they represent one of the most sensitive diagnostic imaging methods, the so-called positron emission tomography. In addition, their incorporation in the molecule of a pharmaceutical does not change the biological and chemical properties of the original molecule unlike those of radiopharmaceuticals labelled with technetium, iodine, etc. (author). 125 refs.

Energy Technology Data Exchange (ETDEWEB)

We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s{sub {gamma}{gamma}} similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

The development of the monitoring network for background measurements of air pollution in the USSR is noted. The use of paired stations, to aid in locating permanent sites as well as for determining the local component of background air pollution, is described. Thermoelectric actionometers with five glass filters are used to measure Shupp's turbidity coefficient for estimating extinction of solar radiation due to aerosols. Sampling and chemical analysis of precipitation uses methods developed during the International Geophysical Year. An intercomparison of meteorological instruments was carried out in the USSR in 1973 and 1978. The most stable actinometer was the Linke-Foisner device. Chemical analyses of precipitation made since 1958 in the USSR show increases in air pollution levels only in particular areas.

Energy Technology Data Exchange (ETDEWEB)

Before disposing of transuranic radioactive wastes in the Waste Isolation Pilot Plant (WIPP), the United States Department of Energy (DOE) must evaluate compliance with applicable long-term regulations of the United States Environmental Protection Agency (EPA). Sandia National Laboratories is conducting iterative performance assessments of the WIPP for the DOE to provide interim guidance while preparing for final compliance evaluations. This volume contains an overview of WIPP performance assessment and a preliminary comparison with the long-term requirements of the Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191, Subpart B).

British Library Electronic Table of Contents (United Kingdom)

A study was conducted to determine the fitting soil moisture for the normal growth of two-year-old W. sinensis (Sims) Sweets by using gas exchange technique. Remarkable threshold values of net photosynthetic rate (Pn), transpiration rate (Tr) and water use efficiency (WUE) were observed in the W. sinensis leaves treated by various soil moisture and photosynthetic available radiation (PAR). The fitting soil moisture for maintaining a high level of Pn and WUE was in range of 15.3%?26.5% of volumetric water content (VWC), of which the optimal VWC was 23.3%. Under the condition of fitting soil moisture, the light saturation point of leaves occurred at above 800?mol?m?2?s?1, whereas under the condition of water deficiency (VWC, 11.9% and 8.2%) or oversaturation (VWC, 26.5%), the light saturatio...

Energy Technology Data Exchange (ETDEWEB)

Ozone plays a critical role in both the chemistry and radiation balance of the troposphere. Understanding the factors controlling tropospheric ozone levels is critical to our understanding of a variety of issues in global chemistry and climate change. Chlorine atoms have the potential to contribute significantly to the ozone balance in the free troposphere. They can react directly with ozone or alternately, with organics and may actually lead to the formation of ozone in the presence of sufficient NO. Reactions of alkali halides in sea salt particles are a potential source of atomic chlorine, hence reactions of these alkali halides, especially those producing precursors to atomic chlorine, are of great interest. Finally, the mechanisms, intermediates and products of the Cl-biogenic reactions are unknown; these could serve as unique markers of chlorine atom chemistry in the troposphere, and hence are important to define.

International Nuclear Information System (INIS)

Within the framework of the Bianchi type-IX homogeneous space, we set up a system of coupled equations for the cosmic scale factors, scalar field, and radiative energy density. At the tree level, the equations are written in a self-consistent, Hartree-Fock form. For phi"4 theory, the system of nine first-order differential equations is solved numerically for a varying ratio of the energy of anisotropy to the vacuum energy. As the vacuum energy increases, there appears to be less reheating, since the energy of anisotropy is more efficiently converted into isotropic expansion. If the energy of anisotropy is large enough, the inflationary phase is prevented. In this case, a series of cosmological phase transitions will take place each time the square of the effective mass changes its sign.

International Nuclear Information System (INIS)

The diagnostic designs for the Laser Megajoule (LMJ) will require components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiations, and, in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced today on existing facilities. The lessons learned about the vulnerabilities of present diagnostic parts fielded mainly on OMEGA for many years, have been very useful guide for the design of future LMJ diagnostics. The present and future LMJ diagnostic designs including this vulnerability approach and their main mitigation techniques will be presented together with the main characteristics of the LMJ facility that provide for diagnostic protection.

Energy Technology Data Exchange (ETDEWEB)

A technique for the measurement of the total hemispherical emittance of pipe surfaces is described, and design and operational details are given. The technique is conceptually simple. A long test pipe (e.g., 3.4 m) is mounted concentrically inside a Pyrex glass pipe. The system is evacuated, and the test pipe is heated by means of an electrical resistance heater. Heat transfer from the test pipe to the enclosure is almost solely radiative, allowing an average emittance for the test pipe and the Pyrex pipe and the electrical power input to the heater. By varying the electrical power level, one can measure the test pipe emittance as a function of temperature. By using a simple correction to account for the finite length of the test pipe, one can calculate the results using the simple expression for infinite, concentric cylinders. Results agree with measurements by reflectance techniques and have a nominal relative error of less than 10%.

International Nuclear Information System (INIS)

There are several methods of generating OH free radicals from ozone and/or hydrogen peroxide and ultraviolet light. They all have in common that the OH free radicals originate in one single source only whereas in the combination of ozone with ionizing radiation two simultaneous working sources for the OH free radicals exist. The resulting higher OH free radical concentration makes this process especially apt for the remediation of low level contaminated groundwater as for example trichloroethylene (TCE) contamination in the sub-ppm range. A cost comparison between O_3/UV and O_3/electron beam for remediation of a groundwater contaminated with 100 ppb TCE indicated that for a throughput of about 5 million gallons/day the O_3/electron beam process is more cost-effective. (authors).

British Library Electronic Table of Contents (United Kingdom)

Purpose ? Aims to present a methodology for analysing a solar-electric, high-altitude, long-endurance, unmanned aircraft. Design/methodology/approach ? The study focuses on the aerodynamics, flight performance and power requirements of a heavier-than-air, solar-electric, HALE UAV. The methodology is founded on using an analytical approach to determine the power required to undertake various flight manoeuvres. An analytical approach is also undertaken in determining the intensity of the solar radiation available to the aircraft. Finally to demonstrate the methodology, a HALE concept was generated and evaluated. Findings ? When using estimates of current solar-electric propulsion and energy conversion efficiencies, the HALE concept was only able to sustain year round, level flight up to lati...

CERN Document Server

In the CERN approach to the design of a neutrino factory, the repetition frequency of the proton beam is high enough to consider stationary solid targets as a viable solution for multi-MW beams. The target consists of high density tantalum spheres of 2 mm diameter which can efficiently be cooled by passing a high mass flow He-gas stream through the voids between the Ta-granules. Very small thermal shocks and stresses will arise in this fine grained structure due to the relatively long burst of 3.3 ms from the SPL-proton linac. In a quadruple target system where each target receives only one quarter of the total beam power of 4 MW, conservative temperature levels and adequate lifetimes of the target are estimated in its very high radiation environment. A conceptual design of the integration of the target into the magnetic horn-pion-collector is presented.

International Nuclear Information System (INIS)

In this paper, we calculated the radioactive concentration distribution of radioactive waste water, the temperature distribution of drained cooling water and the effect of implement from the Daya Bay Nuclear Power Plant on nearby waters range, discussed and analysed some problems of computational results and computation with Alternating Direction Implicit Method (ADI). The contents of the article included: the establishment of two-dimension tidal current equation, radioactive waste water pollutant dispersion equation and cooling water heat convection diffusion equation, the numerical difference calculation model of tidal current field, concentration field as well as temperature field, effect impingement with ADI method, numerical calculation results. The result of research showed that: when the Daya Bay Nuclear Power Plant is on normal operation and after the low level radioactive waste water and low temperature cooling water have been drained off into the sea, it ...

Energy Technology Data Exchange (ETDEWEB)

Diffusion during He/sup +/, Ne/sup +/, and Xe/sup +/ irradiations of trace amounts of Au in melt-spun amorphous Pd/sub 78/Cu/sub 6/Si/sub 16/ has been experimentally investigated. Diffusion constants were measured by following the changes in ion-implanted Au profiles with Rutherford-backscattering spectrometry. Heat treatments and simultaneous irradiations were performed as a function of temperature (533--588 K), ion flux, and ion mass. Total integrated fluences being very small, ion-beam-mixing effects are negligible. More than an order of magnitude enhancement in the diffusion was observed because of irradiations. This enhancement saturates at higher fluxes, the level being independent of ion mass, i.e., independent of collision-cascade parameters. Except at higher temperatures, where the enhancement decreases, the temperature dependence of the diffusion-saturation level is similar to that of the diffusion without irradiation. The data ...

International Nuclear Information System (INIS)

A book has been written to introduce the physical aspects of the radiotherapy electron beam by presenting a summary of the developments in this field. The first chapter is a brief introduction to the technology of medical accelerators with emphasis on the electron beam production facilities. Chapter 2 describes the interaction processes at the atomic level once the electron beam enters the medium. Chapter 3 is concerned with the various properties of the electron beam purely from the clinical point of view. The electron beam algorithms and models for distribution calculations are covered in Chapter 4 with inclusion of age diffusion and multiple scattering approaches. The factors affecting the beam distribution in a patient, with inhomogeneities, surface irregularities, backscattering etc. are discussed in Chapter 5. The last two chapters are devoted to electron beam dosimetry including various dosimetric methods, specification and measurement of beam energy, ...

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The adverse effect of moisture diffusion on the properties of wood has been one of the main weaknesses of wood. Using a gamma irradiation method, wood-polymer composites have been produced which exhibit significant improvement in mechanical properties like compression, creep deformation and creep rupture particularly at high humidity. It has been thought that the impregnation of polymer into the wood has affected the moisture diffusion in the wood, so that its adverse effects on the mechanical properties has been reduced. In this report the apparent diffusion coefficients of a Ramin wood impregnated with varying amounts of polymethyl methacrylate (PMMA) were determined using a Fick's law approach. An initial linear relationship was found for impregnation of up to 70% PMMA, after which the diffusion coefficient levels off to a maximum value, for the three environmental relative humidity levels of 40, 60 and 90({plus minus}5)%. The ...

CERN Document Server

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the latest derived 397 Type Ia supernova (SNe Ia) data, the size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey (SDSS), the position of first acoustic peak of the Cosmic Microwave Background radiation (CMB) from the five years Wilkinson Microwave Anisotropy Probe (WMAP), the x-ray gas mass fractions in clusters of galaxies, and the observational H(z) data. In the original Cardassian model with these combined data set, we find $\\Omega_{m0}=0.271^{+0.014}_{-0.014}, n=0.035^{+0.049}_{-0.049}$ at $1 \\sigma$ confidence level. And in the modified polytropic Cardassian model, we find that $\\Omega_{m0}=0.271^{+0.014}_{-0.015}$, $n=-0.091^{+0.331}_{-1.908}$ and $\\beta=0.824^{+0.750}_{-0.622}$ within $1\\sigma$ confidence level. According to these observations, the acceleration of the universe ...

International Nuclear Information System (INIS)

The details and principles of an apparatus built for measurements of fluorescence quantum yields and cascade-free lifetimes of open-shell cations are reported. These rely on the detection of coincidences between energy selected photo-electrons and undispersed photons. The results of such measurements for CO"+_2,COS"+,CS"+_2 and N_2O"+ in selected vibrational levels of their excited states are presented. Non-unity fluorescence quantum yields are found for some vibronic levels of CO"+_2(B), COS"+(A), N_2O"+(A) and a non-exponential decay is observed for CS"+_2(B). The data yield the following values for the radiative lifetimes: CO"+_2(A) 124 +- 6 ns,CO"+_2(B) 140 +- 7 ns, COS"+(A) 550 +- 50 ns and N_2O"+(A) 240 +- 12 ns. (orig.).

International Nuclear Information System (INIS)

The aim of this study was to evaluate the radioprotective effect of turmeric extract (40 mg/kg body weight) and vitamin E (#alpha# - tocopherol acetate, 400 IU/kg body weight) supplementation on lipid peroxidation, reduced glutathione and antioxidant defense enzymes in various organs like liver, kidney and salivary glands at 24 h in adult Swiss mice. "1"3"1Iodine exposure significantly increased lipid peroxidation in kidney and salivary glands in comparison to control animals. Pre supplementation with turmeric extract for 15 days showed significant lowering of lipid peroxidation in kidney. On the other hand vitamin E pre supplementation showed marked reduction in lipid peroxidation in salivary glands. Reduced glutathione levels decreased significantly in liver after radiation exposure. However, pre supplementation with turmeric extract and vitamin E did not improve glutathione levels in liver. In conclusion we have observed ...

Science.gov (United States)

For the estimation of the dispersion trend of tritium discharged from the Wolsung nuclear power plant, the present level of tritium in environmental samples in the vicinity of the Wolsong site has been studied. On the basis of tritium concentrations in environmental samples, the effective dose due to tritium has been estimated for an individual and population within a 16 km radius from the Wolsong site. The annual effective dose of tritium to an inhabitant around the Wolsong site ranged from 0.15 microSv y-1 to 1.3 microSv y-1. The dose level was negligible and much lower than some applicable standards, i.e. the limit on exposure from nuclear fuel cycle to the general public as recommended by ICRP (1 mSv y-1) or US EPA's limit (0.25 mSv y-1). The collective dose to the total population within a 16 km radius from the site, 1.2 x 10(-2) man.Sv y-1 was much lower than 1 man.Sv y-1, an applicable criterion for the so-called "exemption" of ...

Energy Technology Data Exchange (ETDEWEB)

The influence of low-level microwaves (2.45 GHz, CW, 2 and 5 mW.cm/sup -2/) was studied on various models of previsional animal psychopharmacology involving tests of motor activity, stereotypy, convulsions and hypothermia after a standard 30 min irradiation. The results obtained on 933 rodents allow to conclude that: (1) there is no interaction between microwaves and the studied convulsants and stimulants; (2) there is a possibility of potentialization of the behavioral effects of a tranquilizer; (3) there is a thermogenic effect of microwaves; (4) there is no change of the blood-brain barrier permeability. The demonstration of a thermal effect of microwaves during radiations lower than 10 mW.cm/sup -2/ the safety threshold admitted presently (a value below which the exposure duration comes under regulation) could explain the energetic nature of certain effects of microwaves up-to-now described as non-thermal.

International Nuclear Information System (INIS)

Portuguese Sep-Oct 1996 p. 571 Brazil Campos, Patricia Sao Paulo

Science.gov (United States)

The principles of radionuclide excitation of X-ray fluorescence radiation and its application in

International Nuclear Information System (INIS)

This book gives an overview of the entire field of radiation protection with the subject areas radioactivity, X-rays, UV radiation, laser beams and high-frequency electromagnetic fields. It deals graphically with the most important physical notions, the incidence, origin, properties and biological effects of types of radiation, administrative and practical protection measures and the code of rules governing them. Apart from fundamentals of radiation protection the emphasis on the following: natural radiation exposure, radiation exposure to radon, disaster relief plans in the environment of nuclear plant, the precautionary radiation protection system evolved after Chernobyl, radiation exposure through UV radiation devices, radio, RF communication, radar, microwave ovens and high-voltage transmission ...

Energy Technology Data Exchange (ETDEWEB)

Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences between the effects ...

Energy Technology Data Exchange (ETDEWEB)

Processing certain raw materials containing natural radioactive isotopes (e.g. U-238, Th-232 or K- 40) into products such as glas, abrasives, grinding materials or electrodes used for gasshielded tungsten-arc welding also leads to certain concentrations of industrial waste containing natural radioactive materials. Such industrial waste does not necessarily contain natural radioactive substances in concentrations exceeding the highest possible levels but nevertheless in significantly measurable quantities. This, however, frequently leads to confusion bordering on irritation by entities processing such substances as well as the general public, since they tend to believe natural radioactive substances in unobjectable concentration to cause similar or identical - health - consequences as man made radioactive substances in detrimental concentration. Radioactive materials may be incorporated intentionally or unintentionally into the product as main or additional ...

International Nuclear Information System (INIS)

In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water to determine the irradiation-assisted stress corrosion cracking (IASCC) behavior of HTH Alloy X-750 and direct-aged Alloy 625. New data confirm previous results showing that high irradiation levels reduce SCC resistance in Alloy X-750. Heat-to-heat variability correlates with boron content, with low boron heats showing improved IASCC properties. Alloy 625 is resistant to IASCC, as no cracking was observed in any Alloy 625 specimens. Microstructural, microchemical and deformation studies were performed to characterize the mechanisms responsible for IASCC in Alloy X-750 and the lack of an effect in Alloy 625. The mechanisms under investigation are: boron transmutation effects, radiation-induced changes in microstructure and deformation characteristics, and radiation-induced segregation. Irradiation of Alloy X-750 caused significant ...

International Nuclear Information System (INIS)

Female rats were given tritiated drinking water (3 microCi/ml) from 30 days before mating up to and throughout pregnancy. At this low dose, the course and the outcome of pregnancy were normal. The differences between newborn body and cerebral weights of the treated rats and those of control animals were on the borderline of significance. In contrast, cerebral DNA and cerebral protein were highly significantly lower. In 30-35% of the treated population the DNA and protein values were more than 2 standard deviations (SD) below the mean values for the control population. Thus the number of the progeny of the mothers exposed to tritiated water that were considered to have outstandingly low levels of DNA and protein was 14-17 times greater than in the control group. The irradiated population also had 3-5% of severely affected individuals with cerebral DNA and protein values more than 2 SD below the mean of the experimental population. However, even in this irradiated ...

International Nuclear Information System (INIS)

The role of the HCR system in the repair of prelethal lesions induced by UV light, #gamma# radiation and alkylating agents was studied in the Bacillus subtilis SPP1 phage, its heat sensitive mutants (N3, N73 nad ts_1) and corresponding infectious DNA. The survival of phages and their transfecting DNA after treatment with UV light is substantially higher in hcr"+ cells than in hcr cells, the differences being more striking in intact phages than in their transfecting DNA's. Repair inhibitors reduce survival in hcr"+ cells: caffeine lowers the survival of UV-irradiated phage SPP1 in exponentially growing hcr"+ cells but has no effect on its survival in competent hcr"+ cells; acriflavin and ethidium bromide decrease the survival of the UV-irradiated SPP1 phage in both exponentially growing and competent hcr"+ cells to the level of survival observed in hcr cells; moreover, ethidium bromide lowers the number of infective centres in hcr"+ cells of the ...

Energy Technology Data Exchange (ETDEWEB)

The full text follows. A thermal neutron imaging facility (TNIF) capable of real time neutron radiography and computed tomography was developed for the University of Texas TRIGA Mark II (UT-TRIGA) reactor from 1994-1998. The facility was developed with a through reactor beam port capable of producing a 5.2 x 10{sup 6} n/cm{sup 2}/s thermal neutron flux with a gamma dose rate of less than 1 mR/s after collimation. The original TNIF included the UT-TRIGA reactor, neutron collimation array, sample positioning system, neutron image intensifier tube, video camera, computerized image acquisition system, and a radiation shield. A 0.7 mm slit in cadmium was easily detectable using neutron radiography, and 1.4 mm diameter holes bored in an aluminum block were easily resolved using computed neutron tomography. Precise lower limits of the system resolution have hot been determined. The TNIF is currently being revamped to begin work with the non-destructive evaluation (NDE) of ...

Energy Technology Data Exchange (ETDEWEB)

The spectral characteristics of the Cherenkov radiation have been evaluated and converted to equivalent retinal irradiance from external sources. On the basis of the conversion, electron fluxes have been estimated for 2-sec recovery times from flashblindness. The electrons are assumed to have energies greater than 6 MeV and to be delivered in one or more bursts of 1 microsecond each over 1 sec. It is important to note that very little data exists on recovery times as short as 2 sec for either photopic and scotopic conditions. This situation is a direct result of the lack of definition of the critical tasks and their sensitivity to an interruption of background adaptation. The Cherenkov radiation produced within the eye by relativistic electrons can be compared to light from external sources by the relationships: 1 rad approx. = 4.6 scotopic td-sec and 1 rad approx. = 0.55 photopic td sec. Based on these conversion factors, the following ...

Energy Technology Data Exchange (ETDEWEB)

We present a collisional-radiative approach of the theoretical analysis of laser-induced breakdown spectroscopy (LIBS) plasmas. This model, which relies on an optimized effective potential atomic structure code, was used to simulate a pure aluminum plasma. The description of aluminum involved a set of 220 atomic levels representative of three different stages of ionization (Al{sup 0}, Al{sup +} and Al{sup ++}). The calculations were carried for stationary plasmas, with input parameters (n{sub e} and T{sub e}) ranging respectively between 10{sup 13-18} cm{sup -3} and 0.3-2 eV. A comparison of our atomic data with some existing databases is made. The code was mainly developed to address the validity of the local thermodynamic equilibrium (LTE) assumption. For usual LIBS plasma parameters, we did not reveal a sizeable discrepancy of the radiative equilibrium of the plasma towards LTE. For cases where LTE was firmly believed to ...

International Nuclear Information System (INIS)

By polymerase chain reaction with arbitrary primer (AP-PCR), the possibility of transmission of genome instability to somatic cells of the offspring (F_1 generation) from male parents of mice exposed to chronic low-dose #gamma#-radiation was studied. Male mice 15 days after exposure to 10-50 cGy were mated with unirradiated females. Biopsies were taken from tale tips of two month-old mice progeny for DNA separation. Primer in the AP-PCR was 20-mer oligonucleotide flanking the micro-satellite locus Atplb2 on chromosome 11 of the mouse. Comparative analysis of individual fingerprints of AP-PCR products on DNA-templates from the offspring of irradiated and unirradiated male mice revealed an increased variability of micro-satellite-associated sequences in the genome of the offspring of males exposed to 25 and 50 cGy. DNA-fingerprints of the offspring of male mice exposed to chronic irradiation doses 10 and 25 cGy. 15 days before fertilization (at the post-meiotic stage ...

International Nuclear Information System (INIS)

An attempt was made for early quantitative assessment of the severety of an injury, using the nuclear acids (NA) content as a biochemical indicator. Sexually mature male rats with body mass 160-180 g were irradiated with doses 0.5, 1, 2, 4 and 8 Gy of "1"3"7Cs source. Uneven irradiation was achieved by shielding the abdominal-lumbar area with lead rings, measuring 2,5/50 mm. A 28-30% fall of the dose beneath the shielded zone was thus provided. Dose-dependent quantitative changes in Na content were determined on hours 24 and 72 within the range from 0.5 to 8 Gy and followed up until day 30 after irradiation with nonlethal (2 Gy) and lethal (8 Gy) doses. The total NA content in the leucocytes was determined by the method of Kritski and Aleksandrov. The uneven irradiation of rats within the 0,5-8 Gy range induced early dose-dependent changes in NA content. The nature of their post-irradiation dynamics also depended on the radiation dose and adequately reflected the ...

International Nuclear Information System (INIS)

The late effects of "2"3"9Pu have been studied after its administration to perinatal, juvenile and adult rats. Adults and weanlings were injected intravenously, newborns intracardially and 19-day foetuses by intravenous injection of the dam. Dose levels were selected to deliver radiation doses of approximately 7, 23, or 70 rads to the femur of all ages during the first 10 days post injection; in general these values were achieved as shown by tissue analysis. Dose rates subsequently diverged, resulting in widely varying cumulative radiation doses for the four age groups. Survival times of rats exposed post-natally were progressively decreased by increasing dose. No decrement in survival was found for those exposed prenatally. Bone tumour incidence was increased by exposure to Pu in all age groups. The younger rats were less sensitive on an administered dose basis, but perhaps more sensitive on the basis of cumulative ...

Science.gov (United States)

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Wastenet

Subject to the provisions of the Radiation Protection Act, the Authority, on the advice of ...(f) in collaboration with the Radiation Protection Board, conduct an ionising radiation monitoring programme and ...or document kept under the control of the Radiation Protection Board.

Energy Technology Data Exchange (ETDEWEB)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

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International Nuclear Information System (INIS)

Described and discussed in this paper are radiation processes and their advantages over the conventional techniques. Radiation sterilization of medical products, food irradiation, wood plastic composites, and radiation treatment of sewage and waste waters are presented. The Philippine experience in using these technologies, its problems and barriers are also given. (ELC).

KoreaScience (Korea)

Full Text Available