International Nuclear Information System (INIS)

In radiation processing of food, the product often has to be prepackaged to prevent microbial recontamination during and after irradiation. The packaging material is exposed to radiation during radiation processing and radiation stability is a key consideration in the selection of packaging materials. The effects of ionizing radiation on many food packaging materials at the dose levels recommended for food precessing can be minimized by selecting appropriate radiation resistant materials. It is important to select materials in which chemicals formed as a result of the radiation treatment do not migrate and interact with the food, affecting its organoleptic and toxicological aspects. It is also important to select materials in which the physical properties are not altered to the extent they cannot resist damage during commercial production, ...

UK PubMed Central (United Kingdom)

In the present study we have used the alkaline elution technique to study the effect of misonidazole (MISO) on the initial amount of DNA cross-linking in various normal and neoplastic tissues of C3H...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Soluble starch?based biodegradable and microporous microspheres (SDM-Ms) were prepared by emulsion chemical cross-linking technique using trisodium trimetaphosphate (TSTP) as the cross-linker. The resultant amorphous SDM-Ms were excellently identified by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The internal rupture and surface-controlled erosion were the predominant degradation mechanisms for SDM-Ms. The obtained SDM-Ms were applied to adsorb coix seed oil (CSO) by immersing method. The adsorption capacity of CSO within SDM-Ms was determined, namely 0.5238?g/g, and the thermal stability was shown higher than that of the free CSO. A burst release appeared in the second hour, followed by controlled release. Diffusion, d...

International Nuclear Information System (INIS)

Polytetrafluoroethylene was obtained by radiation induced polymerization of tetrafluoroethylene in acetone at 195 K. An average diameter of the products was very small compared with commercial one; it was about 0.3 micro-meters. The yield was reached to 100% with a dose of 4 kGy. The crystallinity of the products is decreasing with increasing dose. The products become amorphous, for higher irradiation doses. It was found that PTFE obtained by irradiation of TFE in acetone at 195 K has branching structure. This was demonstrated by means of "1"9F MAS NMR. (Author)

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.

International Nuclear Information System (INIS)

The synthetic process of polyethylene cation exchange capillary via radiation grafting polystyrene by simultaneous irradiation with "6"0Co #gamma#-ray source and sulfonation with concentrated H_2SO_4 was studied. The effects of dose, dose rate, monomer concentration, solvents, temperature and crosslinking agents on the graft copolymerization of styrene with polyethylene capillary were illustrated. The relationship between the radiation grafting conditions and the properties of ion-exchange capillary were examined. A polyethylene cation exchange capillary with I.D. 0.8 mm, length 20 m, exchange capacity 0.7 Meq/g 60% capacity in 10 s (flow rate 20 ml/min) was prepared. No significant loss of copacity was found from this ion-exchange capillary after 200 adsorption/regeneration cycles.

Energy Technology Data Exchange (ETDEWEB)

Hungary has 10.7 million population in 100,000 km/sup 2/ territory. The gross national product is about $3,000 per capita per year. Hungary is a country with highly developed agriculture and medium degree developed industries. The Hungarian economy is an open economy because more than 40% of the national income is earned by export. The research and development works on various radiation processing have been performed for 25 years. In the Central Research Institute for Physics of the Hungarian Academy of Sciences, a laboratory was organized for the basic research of radiation chemistry and the moderator materials for nuclear reactors. Also the activities in the Central Research Institute for Chemistry, the Institute of Isotopes, the Research Institute for Plastics Industry, and the Central Research Institute for Food Industry are briefly reported. The largest radiation processing unit in Hungary is the automatic ...

International Nuclear Information System (INIS)

(1985). USSR Nedavnij, OI Tomskij Politekhnicheskij Inst. (USSR).

International Nuclear Information System (INIS)

The radiation induced reactions in LDPE in the presence of phenolic type antioxidants have been studied. It was shown that various antioxidants can influence the polyethylene network formation and the radical yield in different ways. The dependence of network structure on absorbed doses was determined by gel analysis, hot-set test and extraction of antioxidants for samples irradiated with accelerated electrons. It was found that the antioxidants eluted from polyethylene in higher percentage influence polymer crosslinking to a smaller degree. The ESR studies of #gamma#-irradiated blends of polyethylene with antioxidant indicate the presence of alkyl and phenoxyl radicals. The role of antioxidant molecules on radiation induced reactions in polyethylene-antioxidant systems is considered. The correlation between the network structure and the type of additive in polyethylene is also discussed. (author).

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).

Science.gov (United States)

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International Nuclear Information System (INIS)

Electron beam (EB) processing involves using electrons to initiate polymerization or cross-linking reactions in suitable substrates, thereby enhancing specific physical and chemical properties. A relatively new use of EB processing is now emerging: the production of fibre-reinforced composites. EB curing at ambient temperature has the potential to reduce the residual stresses in an advanced composite, a result of expansion during thermal curing, and to significantly increase the overall cure speed and process throughput. Wood fibres are used as a filler material for various thermoplastics such as polypropylene. EB treatment, combined with selected EB-curable coupling agents, significantly increases the adhesion between the wood fibres and the thermoplastic polymer, resulting in improved material properties. Work to develop both products and processes for the EB curing of fibre-reinforced composites is currently underway at AECL Research. This paper briefly updates ...

International Nuclear Information System (INIS)

Dosimetric studies in 80 patients examined with the tomographic device 'Somatom' are reported. The gonad doses are compared to those of conventional radiographic techniques.

CERN Document Server

We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition Undulator Radiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for ...

UK PubMed Central (United Kingdom)

The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene...Full Text Available

International Nuclear Information System (INIS)

Non-destructive methods of diagnosis for detecting cable degradation by aging are being studied recently for improvement of electric wires and cables. This study examines degradation behaviors of cable sheath and insulation by combined accelerated aging tests applying thermal and radiation stresses simultaneously using a typical low voltage cable. According to experiments, elongation of cross-linked polyethylene insulation deteriorated at a faster rate than PVC sheath did under low doses below 50 Gy/h. Therefore, measurements using a time domain dielectric spectrometer (TDS) were carried out for the purpose of developing a method of degradation diagnosis of insulation. It was found that values of tan#delta# measured at very low frequencies below 0.1 Hz increase in pace with degradation of insulation reflecting the level of degradation more effectively than those measured at frequencies around the commercial frequency. In order to consider ...

Science.gov (United States)

... Abstract in early 1996 Milstar became the first geosynchronous satellife system to employ crosslinks for synchronization and syntoniulfion. ...

Science.gov (United States)

The purpose of this study was to prepare recombinant human epidermal growth factor (rhEGF) collagen sponges for topical applications and investigate the effects of different types of crosslinked collagen sponges as platforms for the controlled release of rhEGF. The microstructure and the drug release rates of collagen sponges were modified through treatment with different types (glutaraldehyde (GTA), genipin and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)), different concentrations of crosslinking agents and various preparation conditions. A controlled release profile was observed for the crosslinked collagen sponges as compared to the non-crosslinked ones. The results indicated that the GTA crosslinked sponges have the most potent controlling effect. As the amount of GTA increased, a greater rigidity of the collagen sponge structure combined with a lower hydrophilicity was ...

International Nuclear Information System (INIS)

The annealing behavior of the radiation damage in epitaxial Pd_2Si and NiSi_2 films on Si, due to the implantation of 100 keV Ar ions, is investigated by using the channeling technique with "4He ions. (U.K.).

International Nuclear Information System (INIS)

The introduction of tolerance to radiation (''radiation-hardness'') into large electronic systems is one of the major tasks to which this Handbook will be put. The practices recommended here for inculcating radiation-tolerance in equipment require advanced physical modeling techniques, precise engineering procedures, and firm assurance procedures. The degree to which these procedures should be used in an equipment project can be measured by the severity of the raw radiation environment, the desired reliability of the system, and the requirement of that project for radiation-sensitive technologies. The balance of device/circuit design versus shielding will depend on whether the radiation is highly penetrating -- as in isotope handling or military environments -- or readily attenuated, as in space. In this chapter the authors have attempted to ...

International Nuclear Information System (INIS)

The main aim of any food irradiation treatment is to guarantee the best safe quality of the products, reducing the spreading risk ("cross-contamination") for several food-associated diseases. Actually, over 40 countries provide clearances for the treatment of about 45 different types of foodstuffs. EU has to homogenise the situation within the associated States. With the European directive 1999/2/EC Italy, as other EU countries, already has brought into force their regulations to comply. The current Italian regulation on irradiation treatment of foodstuffs is referred since 1996 as follows: a) potatoes, onions and garlic; b) spices, herbs and condiments microbial. The new (April 2001) Italian law allows the possibility to ask for special permission of treatment for other foodstuff which is possible to treat in other E.U. countries. Large majority of foods are submitted to irradiation treatment after they have been packaged. In Dutch cases the study of radiation ...

Energy Technology Data Exchange (ETDEWEB)

In order to judge the potential fluorescent lamp applications of various low-pressure positive column discharges it is necessary to measure the absolute power emitted in the ultraviolet region of the spectrum. For rare-gas discharges the principle emission occurs in the vacuum ultraviolet so that it is difficult to measure the radiant emittance (power per unit area) of the resonance radiation by standard methods. Two independent techniques are discussed for measuring the radiant emittance of positive column discharges in the vacuum ultraviolet. These techniques are used to study xenon positive column discharges at the resonance wavelength of 147 nm. The first method relies on the measurement of the resonance level density by absorption techniques. The effective decay rate of the resonance level is then determined by the simulation of resonance radiation transport. These two ...

International Nuclear Information System (INIS)

By measuring organ doses with TLD at an Alderson-Rando-phantom it was tested to evaluate the somatic risk for mammographies. Similarly as the genetic risk can be expressed by the genetic significant dose, the somatic risk can be expressed by the somatic significant dose index. The measurement results of the mammography show a large deviation of almost one power of ten with dependence of the chosen technique. In conventional xeroradiography and recording technique with foilless film the somatic radiation risk is the highest. By using amplifying foils in combination with high-sensitive films it is relatively small. Unfortunately the magnitude of the somatic risk in the different mammography techniques is in the ratio reciprocal to the corresponding image quality. At the time being the most favourable technique is mammography with a soft rastering method, although the xeromammography ...

Energy Technology Data Exchange (ETDEWEB)

Four general topics are covered in respect to the natural space radiation environment: (1) particles trapped by the earth`s magnetic field, (2) cosmic rays, (3) radiation environment inside a spacecraft, (4) laboratory radiation sources. The interaction of radiation with materials is described by ionization effects and displacement effects. Total-dose effects on MOS devices is discussed with respect to: measurement techniques, electron-hole yield, hole transport, oxide traps, interface traps, border traps, device properties, case studies and special concerns for commercial devices. Other device types considered for total-dose effects are SOI devices and nitrided oxide devices. Lastly, single event phenomena are discussed with respect to charge collection mechanisms and hard errors. (GHH)

British Library Electronic Table of Contents (United Kingdom)

The initial management of nonfunctioning pituitary macroadenomas (NFAs) is usually surgery; however, a significant proportion of NFAs may require further treatment. Radiotherapy is currently used in patients with residual tumour and achieves excellent long-term control, but there are concerns about potential late toxicity. Stereotactic radiotherapy, both in the form of radiosurgery or fractionated stereotactic radiotherapy, has been developed as a more accurate technique of irradiation with more precise tumour localization and consequently a reduction in the volume of normal tissue, particularly the brain, irradiated to high radiation doses. A review of the literature suggests that new radiation techniques offer safe and effective treatment for recurrent or residual pituitary adenomas; how...

Energy Technology Data Exchange (ETDEWEB)

An overview of the operations of Sandia`s Microelectronics Development Lab (MDL) is to develop radiation hardened IC, but techniques used for IC processing have been applied to a variety of related technologies such as micromechanics, smart sensors, and packaging.

Energy Technology Data Exchange (ETDEWEB)

The patient positioning and repositioning control in radiation therapy all along the treatment can be conducted using a variety of X-ray sources and imaging detector devices. The development of image guided radiation therapy techniques leads to more frequent use of this imaging control. In this article we summarize the current methods for measuring the dose delivered by X-ray imaging devices used in radiation therapy, as well as basic proposals to take account of these imaging doses for prescribing, recording and reporting radiation therapy treatment. (authors)

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 product can be ...

Energy Technology Data Exchange (ETDEWEB)

Structure of ferrite in drawn pearlitic steel containing 0.9 mass% C was investigated with X-ray diffraction technique using synchrotron radiation. In the detailed analysis of diffraction peaks of ferrite during the drawing process, it was experimentally revealed that the transformation of ferrite from bcc to bct due to the supersaturation of carbon in ferrite of heavily drawn pearlitic steel.

International Nuclear Information System (INIS)

A network of second-generation low-temperature gravitational radiation detectors is nearing completion. These detectors, sensitive to mechanical strains of order 10"-"1"8, are possible because of a variety of technical innovations that have been made in cryogenics, low-noise superconducting instrumentation, and vibration isolation techniques. Another five orders of magnitude improvement in energy sensitivity of resonant-mass detectors is possible before the linear amplifier quantum limit is encountered. 33 references, 3 figures, 1 table.

Energy Technology Data Exchange (ETDEWEB)

Plantago ovata Forsk - an economically important medicinal plant - was analyzed for trace elements and chlorophyll in a study of the effects of gamma radiation on physiological responses of the seedlings. Proton-induced X-ray emission (PIXE) technique was used to quantify trace elements in unirradiated and gamma-irradiated plants at the seedling stage. The experiments revealed radiation-induced changes in the trace element and chlorophyll concentrations.

International Nuclear Information System (INIS)

As there are many efforts devoted in order to manage the cancer, here the researcher handle one of these efforts that play a major part in treating the cancer internationally, it is a brachytherapy system. Brachytherapy was carried out mostly with radium sources, but recently some artificial sources are incorporated in this mode of treatment such as Cs-137, Ir-192, Au-198, P-32, Sr-90 and I-125. The research cover history of brachytherapy and radioactive sources used in, techniques of implementation, radiation protection and methods of brachytherapy dose calculation, as well as brachytherapy in radiation and isotopes centre in Khartoum.

International Nuclear Information System (INIS)

The paper presents information in the form of data, tables and diagrams compiled to a broad but very up-to-date survey of required radiation for the various most frequently performed X-ray examinations of patients. The required dose is discussed from the point of view of radiation protection, defining the inevitably administered dose to the skin, the frequency of examinations, and the diagnostic image quality as the main three factors to be observed, as these determine the radiation dose to the patient and to the personnel. The somatic risks of radiography examinations are a point of main interest. (DG).

International Nuclear Information System (INIS)

Formulae are derived for estimation of the effect of gamma beam divergence on the value of systematic and statistical components of the errors of density measurement in production of structural materials and products also in the process of exploitation of building structures and constructions. Engineering technique for choice of the distance between radiation source and object under test is developed for absorption radioisotope densimeter operating by the scheme of geometry of divergent beam with amplitude compensation of backscattered radiation effect. The assessment of radioisotope densimeter efficiency providing the error of density measurement prescribed at design stage

British Library Electronic Table of Contents (United Kingdom)

Natural rubber (NR) and its derivatives as renewable and biodegradable materials have attracted considerable attention because of the serious pollution problems caused by synthetic materials and a shortage of resources. A new semi-interpenetrating polymer network (semi-IPN) based on epoxidised natural rubber and polyvinyl alcohol containing maleic acid as a crosslinking reagent was synthesized and characterized by FTIR, XRD, SEM, swelling ratio in both distilled water and toluene, and mechanical properties. The curing time and dose of maleic acid were varied from 10 to 60min, and from 10 to 60% (w/w), respectively. An IR spectroscopic study indicated the presence of an ester linkage at 1730cm-1 in maleic acid crosslinked with PVA in semi-IPN films. In addition, the crystalline content of P...

Energy Technology Data Exchange (ETDEWEB)

Compton scatter tomography utilizes the electronic collimation characteristics available through the Compton scattering angle-energy correlation to obtain tomographic images. In this work we present particular aspects of the technique, which are relevant to the inverse radiation transport problem of reducing marginal projection data to radial two-phase flow regime maps. The results indicate a viable technique for the tomographic imaging of tow-phase flow using practical source strengths and reasonably few detectors.

Science.gov (United States)

Leachability of neutron irradiated fly ash is investigated as a method for studying element leaching properties of this material with various leaching media. Quantitative aspects of radiation damage are shown to be minor. Therefore, the technique should be applicable for this purpose. It is further shown that this technique affords significant advantages over the conventional post-leaching analysis with respect to utilization of natural solutions for the investigation of fly ash leachability. However, for a few elements such as Pb, Bi, V, and Al, the various nuclear parameters involved invalidate applicability of the present technique.

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 ...

UK PubMed Central (United Kingdom)

Amidination of aldolase, glyceraldehyde-3-phosphate dehydrogenase, tryptophan synthetase B protein, L-arabinose isomerase, and the catalytic subunit of E. coli aspartate transcarbamylase...Full Text Available

UK PubMed Central (United Kingdom)

The gelation kinetics of an in situ gelable hydrogel formulated from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) were investigated rheologically. Both Schiff base...Full Text Available

UK PubMed Central (United Kingdom)

A series of in situ gelable hydrogels were prepared from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) without any extraneous crosslinking agent. The gelation readily...Full Text Available

UK PubMed Central (United Kingdom)

Antibodies to myelin oligodendrocyte glycoprotein (MOG) have been implicated in Multiple Sclerosis demyelination through activation of complement and/or macrophage-effector processes. We presented...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This patent describes a delayed acrylamide containing polymer crosslinker having stability in an aqueous solution at high temperatures. It comprises: a combination of an aldehyde and a salicylic acid derivative selected from salicylamide and acetysalicylic acid.

International Nuclear Information System (INIS)

The time and dose characteristics of the electron and X-ray radiations of a tube, connected to a subnanosecond mega volt accelerator, are measured. By the pulse of the accelerating voltage of #>=# 600 kV with duration of #approx =# 0.3 ns the tube generates approximately 5 x 10"1"2 electrons pulse. The current amplitude equals approximately 5 kA/pulse and the radiation dose-about 5 kGy/pulse. The X-ray radiation dose from the tantalum external target constitutes 0.15 Gy/pulse. The prototypes of the electron and X-ray tubes sufficiently lower volumes, opening new applications in the technique and medicine, are developed

International Nuclear Information System (INIS)

A study of the influence of the concentration of secondary addition, high concentrations of primary dopant, diffusion enhancer and stabilizer on radiation hardness is presented. It is concluded that the diffusion enhancing technique is the most powerful method for improving radiation hardness. A new polystyrene scintillator which contains 2% pT, 0.02% POPOP, 20% diffusion enhancer and 0.02% stabilizer gave 91% of initial light output immediately after 3 Mrad irradiation in air. Data are presented that show that scintillator prepared from commercial polymer is more radiation-hard and has greater light output than scintillator prepared from monomer. It is assumed that this difference is due to different molecular weight distributions. Some protocols for acceleration of aging (yellowing and crazing) are presented. It is shown that one of the main reasons for aging of plastic scintillators is residual ...

Energy Technology Data Exchange (ETDEWEB)

This report concerns investigations in the title conducted by 8 groups of National Institute of Radiological Sciences (NIRS) during the period of 1998-2000. The groups are for investigation of: Effects of p53 tumor suppressor gene in radiation-induced leukemia, Role of atm-gene in dose rate effect of ionizing radiation, Function of DNA-dependent protein kinase catalytic subunit (DNA-PK{sub cs}), Functional complementation of radiation-sensitive mutant M10 cell line by human XRCC4 cDNA expression, Role of radiation-induced apoptosis in digital defects in embryonic mice, Functional analysis of S-phase specific novel nuclear protein NP95 by gene targeting, Role of chemokine in T cell development and lymphomagenesis, and establishment of production techniques of gene-modified mice using embryonic stem cells for genetic analysis of radiation-sensitive genes. The ...

Energy Technology Data Exchange (ETDEWEB)

The resistance of six tropical hardwoods to fungal degradation by two wild-type strains of Phanerochaete chrysosporium Burdsall was investigated using vermiculite burial and wood-block weight loss techniques. Radiation-induced wood-polymer composites (WPC), based on two hardwoods Ramin and Rubberwood with methyl methacrylate, were prepared, and samples were also exposed to the wood-rotting fungus. A significant improvement in resistance to fungal decay was observed in the WPC. Scanning-electron micrographs of the two woods and their composites after fungal degradation are presented and discussed.

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is to determine and compare the dosimetric properties of NaCl and KCl samples using infrared-stimulated luminescence (IRSL) technique. For a material to be used as dosimeter, both the IRSL temperature dependence and the radiation dose response have critical importance. In this work the IRSL characteristics from NaCl and KCl samples were experimentally investigated as a function of temperature and laboratory radiation doses. Dosimetric properties of NaCl and KCl samples were found significantly different. The IRSL signals displayed by NaCl were found to be more stable, reliable and agreeable than those of KCl.

Science.gov (United States)

The present contribution deals with the thermophoresis particle deposition and thermal radiation effects on the flow, heat and mass transfer characteristics in a viscous fluid over a semi-infinite vertical porous plate. The governing boundary layer equations are written into a dimensionless form by similarity transformations. The transformed coupled nonlinear ordinary differential equations are solved numerically by means of the fourth-order Runge-Kutta method with a shooting technique. The effects of different parameters on the dimensionless velocity, temperature, and concentration profiles are shown graphically. In addition, results for the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are tabulated and discussed.

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.

CERN Document Server

We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interplanetary radiation conditions analogs. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70-80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a ...

International Nuclear Information System (INIS)

A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through detrending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality.

CERN Document Server

An algorithm for creating synthetic telescope images of Smoothed Particle Hydrodynamics (SPH) density fields is presented, which utilises the adaptive nature of the SPH formalism in full. The imaging process uses Monte Carlo Radiative Transfer (MCRT) methods to model the scattering and absorption of photon packets in the density field, which then exit the system and are captured on a pixelated image plane, creating a 2D image (or a 3D datacube, if the photons are also binned by their wavelength). The algorithm is implemented on the density field directly: no gridding of the field is required, allowing the density field to be described to an identical level of accuracy as the simulations that generated it. Some applications of the method to star and planet formation simulations are presented to illustrate the advantages of this new technique, and suggestions as to how this framework could support a Radiative Equilibrium ...

International Nuclear Information System (INIS)

A radiometric method of measuring the ratio of liquid and solid phases (crust thickness) in a continuous ingot for automation of the continuous steel casting process, has been proposed. The essence of the method is, that radiation flux, bearing information on the object tested, is transformed in a succession of electric pulses, which is processed afterwords for obtaining necessary information. In this case either the flux of non-scattered radiation, passed through the object, or the flux of single-scattered radiation reflected from the object is registered. Block-diagram and specifications of a radiometric device with the Co source of 50 gxequiv. Ra activity developed for this purpose are presented. The technique for calibration ob the device and the results of its tests, are described. It is shown, that introduction of such devices for the control crust thickness at the installations of continuous ...

International Nuclear Information System (INIS)

Full text: The principal nuclear design tools available to the shielding designer include diffusion approximation, transport theory, and Monte Carlo techniques. Full transport theory or Monte Carlo methods are routinely used for shielding analyses, where penetration investigations are more sensitive to directional aspects. However, the aim of this paper is to illustrate the coupled neutron-gamma Albedo method particularly as applied to problems of shielding analysis. The multigroup Albedo method is applied to coupled neutron-gamma radiations considering 'n' neutron energy groups and 'g' gamma energy groups to estimate the probabilities of transmission through, absorption in, and reflection from shieldings composed by multiple material layers, 'm' slabs, in which no fission occurs. In this study, these energy groups were selected in order to minimize upscattering effects of the radiation from lower energy groups to higher ...

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 ...

CERN Document Server

All-order spurion-corrected superpropagators and superfield Feynman rules are employed to systematically compute a two-loop corrected effective potential for the O'Raifeartaigh model, that realizes spontaneous supersymmetry breaking. Though the shifted superpropagators are rather nontrivial, superspace techniques may be suitably extended and confirm their efficacy in computing radiative corrections even when supersymmetry breakdown occurs.

Energy Technology Data Exchange (ETDEWEB)

From the numbers of radiographs of the different examinations and the total amount of radiological diagnostics in the GDR their possible modification by new imaging techniques is discussed under the aspects of costs and radiation burden. Film-screen-systems are of special importance, because they also will be most frequently used image recording system in future. The importance of their various properties and parameters, methods of determining these parameters as well as future developments are analyzed from the standpoint of practical requirements.

Energy Technology Data Exchange (ETDEWEB)

The Commission of the European Communities has submitted a directive for the protection against microwaves. According to this directive, exposures above the upper limit established for the protection of individuals and the general population are permissible only if the respective individuals are required to submit to occupational medical control. An introductory overview is presented giving information on microwaves, applied techniques and available protective means.

Energy Technology Data Exchange (ETDEWEB)

Heat transfer has emerged as a leading-edge technology supporting the rapid pace of developments in science and engineering ranging from energy production to electronic cooling. Subjects covered at the 6th UK National Conference on heat transfer held at Edinburgh from 15-16 September 1999 include: convection; boiling and evaporation; condensation; numerical techniques; heat exchangers; radiation and combustion; conduction; two-phase flow and heat transfer augmentation. Fifteen of the papers are abstracted here.

Energy Technology Data Exchange (ETDEWEB)

An embodiment of a mercury-free fluorescent lamp combines a low pressure rare gas discharges with a phosphor having a quantum efficiency grater than one. The choice of the rare gas depends on a number of factors, one of which is the resonance transition energy. Less demand is placed the quantum efficiency of the phosphor for a lower energy resonance photon. Xenon has the lowest energy resonance transition of the stable rare gases at 8.5 eV (147 nm) and thus is a good candidate to study. The usefulness of a xenon-based discharge depends on the radiant emittance of the discharge at the resonance wavelength of 147 nm. The radiant emittance from a low pressure xenon positive column discharge is measured using two independent techniques. The first relies on the measurement of the resonance level density using absorption techniques. The effective decay rate of the resonance level is calculated using radiation trapping theory. The ...

Energy Technology Data Exchange (ETDEWEB)

A brief comparative review of possible mercury free fluorescent lighting technologies is presented, including rare-gas positive column discharges, molecular discharges, and dielectric barrier discharges. Detailed experimental results on xenon positive column discharges will then be considered. In order to judge whether xenon-based discharges are a viable UV source it is necessary to measure the radiant emittance (power per unit area) for the vacuum ultraviolet (VUV) resonance xenon emission at 147 nm. Two techniques to determine the VUV radiant emittance have been developed and applied to xenon discharges. One method combines the measured resonance level density using absorption spectroscopy and a calculation of the trapped decay rate for the resonance radiation to arrive at the radiant emittance at 147 nm. A second method utilizes a direct measurement of the radiance (power per unit area per unit solid angle) at 147 nm using a calibrated VUV ...

International Nuclear Information System (INIS)

The purpose of this study was to determine the optimal technique for delivering postoperative radiotherapy for vulvar cancer and other tumors requiring treatment of the inguinal nodes. This project compared tumor coverage and normal tissue sparing for the 5 main radiotherapy techniques that are used to treat vulvar cancer. The intensity-modulated radiation therapy (IMRT) plan was undesirable because it resulted in an excessive dose to portions of the central pelvic structures. The photon thunderbird with skin match was unacceptable because it underdosed a portion of the groin region. The electron thunderbird was ideal for thin patients but was not applicable for most patients because of excessive dose to the skin and subcutaneous tissues. The photon through-and-through and the photon thunderbird with deep match were acceptable in most situations. In thin patients, where the depth of the inguinal vessels is less than 3 cm, ...

Energy Technology Data Exchange (ETDEWEB)

The Dowex 50W-X8 and 50W-Xl2 resin samples are both strong acid cation materials in the hydrogen form. Each material has a water retention capacity characteristic of its respective marketed degree of cross-linking. Dowex 21K gives confirmatory responses to tests for a strong anion exchange resin in the nitrate form. All three resins have the manufacturer's specified ionic type and form, and the Dowex 50W resins have characteristic water retention capacities. These tests conclude that the ion exchange resins in use in FB-Line meet the approved safety document criteria for cross-linking, ionic form, and resin type.

British Library Electronic Table of Contents (United Kingdom)

Protein hydrogels were prepared by substituting ovalbumin with different concentrations of ethyl vinyl sulfone (EVS) or acrylic acid (AA) and crosslinking with divinyl sulfone (DVS). Fourier transform-infrared (FT-IR) spectroscopic studies confirmed the addition of EVS, AA, and DVS onto the protein. Swelling was assessed as a function of pH in the range of 2.5 to 9.4 and ionic strength. The elastic modulus of the gels was determined in shear and compression. Stress relaxation was assessed in compression. The substituent highly affected swelling and modulus with both hydrogels displaying non-Gaussian behavior in the range of hydrogel environments studied. Acrylic acid substituted ovalbumin exhibited a decreasing modulus with increasing swelling behaving as a polyelectrolyte with low added s...

Energy Technology Data Exchange (ETDEWEB)

This project is concerned with a basic scientific question concerning the properties of coal--to what extent is the ability of coal to hold moisture a manifestation of the well-known ability of coal to swell, when exposed to good solvents The question implies that the long-held belief that coal holds a significant portion of its moisture by classical capillary condensation processes, is possibly in error. It is likely that a sound approach to permanent drying would involve highly crosslinking the coal at mild drying conditions. The crosslinked coal could not swell sufficiently to hold much water. It is identifying processes to achieve this goal, that constitute the objective of the second phase of this work. 25 refs., 4 figs., 1 tab.

International Nuclear Information System (INIS)

High energy physics facilities must monitor the radiation doses received by their personnel. This monitoring can only be effective if the radiation detection devices can be calibrated with a good degree of accuracy. Radiation fields are usually composed of several types of radiation, including gamma rays, beta radiation, neutrons, etc. The neutron detection instruments respond not only to the neutrons coming directly from the source but also those scattered from the floor, walls, and ceiling. The amount of neutron scattering varies from site to site depending on the construction materials and layout of the building. The purpose of this study was to determine the scattered neutron fraction in the central volume of the calibration mezzanine of the Radiation Physics Calibration Facility (RPCF) at the Fermi National Accelerator Laboratory (Fermilab). At Fermilab, ...

Energy Technology Data Exchange (ETDEWEB)

This research focuses on the development and application of high order statistical analyses applied to measurements performed with subcritical fissile systems driven by an introduced neutron source. The signatures presented are derived from counting statistics of the introduced source and radiation detectors that observe the response of the fissile system. It is demonstrated that successively higher order counting statistics possess progressively higher sensitivity to reactivity. Consequently, these signatures are more sensitive to changes in the composition, fissile mass, and configuration of the fissile assembly. Furthermore, it is shown that these techniques are capable of distinguishing the response of the fissile system to the introduced source from its response to any internal or inherent sources. This ability combined with the enhanced sensitivity of higher order signatures indicates that these techniques will be of ...

Energy Technology Data Exchange (ETDEWEB)

An essential part of fire risk assessment is the analysis of fire hazards and fire propagation. In this work, models and tools for two different aspects of numerical fire simulation have been developed. The primary objectives have been firstly to investigate the possibility of exploiting state-of-the-art fire models within probabilistic fire risk assessments and secondly to develop a computationally efficient solver of thermal radiation for the Fire Dynamics Simulator (FDS) code. In the first part of the work, an engineering tool for probabilistic fire risk assessment has been developed. The tool can be used to perform Monte Carlo simulations of fires and is called the Probabilistic Fire Simulator (PFS). In Monte Carlo simulation, the simulations are repeated multiple times, covering the whole range of variability of the input parameters and thus resulting in a distribution of results covering what can be expected in reality. In practical applications, advanced ...

Energy Technology Data Exchange (ETDEWEB)

Biodegradable and green plastics are the new tendency in the world. The effect of the electron beam irradiation in aromatic aliphatic copolyester and the blend with corn starch films (Ecoflex{sup R} and Ecobras{sup R}) were studied by tensile strength at break, elongation at break, Scanning Electronic Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), crosslinking degree and biodegradability. The measurements in both, the machine direction and the transverse direction were made for mechanical tests. It was found that, the electron irradiation caused an increase in the strength at break of the blend with corn starch film, when doses of up to 10 kGy were applied. A significant decrease of the elongation at break of the blend with corn starch was observed at doses of 10 kGy and 40 kGy. It was not found important change in tensile properties for aromatic aliphatic copolyester. Structural changes of the samples ...

UK PubMed Central (United Kingdom)

A refined map for the linear arrangement of histones along DNA in nucleosomal core particles has been determined by DNA-protein crosslinking. On one strand of 145-bp core DNA, histones are aligned in...Full Text Available

Science.gov (United States)

The production of water from a subterranean formation is reduced by contacting the formation with a water dispersible hydrophilic organic polymer having a molecular weight greater than 100,000 and containing carboxyl functionality and a crosslinking composition comprising water, a zirconium compound having a value of 4+, an alpha-hydroxy acid and an amine compound.

Energy Technology Data Exchange (ETDEWEB)

The newly developed techniques by the Hot Laboratory (JMTR HL) have provided for us the key information on behavior of specimens due to mechanical / physical / chemical / synergistic effects of radiation, stress and water for fission and fusion reactor environment. These techniques are focused on several topics as follows; (1) miniaturized specimen test for the development of fusion reactor materials, (2) slow strain rate tensile testing (SSRT) and crack propagation measuring tests for the study of Irradiation Assisted Stress Corrosion Cracking (IASCC) of core internals of LWR, (3) handling technique on specimens including tritium for the research and development of tritium breeders and neutron multiplier as fusion blanket materials, (4) joining method using the Tungsten Inert Gas (TIG) welding technique for re-assembling of capsule and re-fabrication of specimen and (5) ...

International Nuclear Information System (INIS)

... radiation effects RADIATIONS. WOOD-PLASTIC COMPOSITES.

British Library Electronic Table of Contents (United Kingdom)

In this article, we present our consistent efforts to explore the dynamical pathways of the migration of electronic radiation by using ultrafast (picosecond/femtosecond time scales) F?rster resonance energy transfer (FRET) technique. The ultrafast non-radiative energy migration from an intrinsic donor fluorophore (Tryptophan, Trp214) present in domain IIA of a transporter protein human serum albumin (HSA) to various non-covalently/covalently attached organic/inorganic chromophores including photoporphyrin IX (PPIX), polyoxovanadate [V15As6O42(H2O)]-6 clusters (denoted as V15) and CdS quantum dots (QDs) has been explored. We have also used other covalently/non-covalently attached extrinsic fluorogenic donors (NPA, ANS) in order to exploit the dynamics of resonance energy migration of an enz...

International Nuclear Information System (INIS)

Silica glasses containing Pr"3"+ with and without CdS nanoparticles were prepared by sol-gel technique. The influence of CdS nanoparticles on Pr"3"+ doped glass was studied by absorption, photoluminescence and up-conversion. From the measured intensities of various absorption bands of these glasses, the Judd-Ofelt parameters ?_2, ?_4 and ?_6 have been evaluated. The radiative transition probability (A), radiative lifetime (?_R), branching ratio (?_R) and integrated emission cross-section (?_P) were calculated from excited states of "3P_1 and "3P_0 levels. The up-conversion emissions were found in the green, orange and red regions under 800 nm excitation with peaks 559, 612 and 688 nm respectively. On excitation with 370 nm also leads to similar green, orange and red regions.

International Nuclear Information System (INIS)

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85"0C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to #gamma#-rays. A thin aluminium foil was used to cover the inner wall of the reaction vessel so that the extent of homo polymer could be reduced to be less than 1.6% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmations of graft copolymerization and saponification reactions were made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the same total dose on the extent of grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

Energy Technology Data Exchange (ETDEWEB)

Fifty-nine patients underwent free flap osteocutaneous reconstruction that consisted of flaps of the dorsum of the foot in 26 patients and iliac crest flaps in 33 with a success rate of 92 percent and a mortality rate of 1.6 percent. These flaps, which require the expertise of microvascular surgeons, are time-consuming and complicate operating room and time management, but they represent a remarkable advance in reconstruction that can facilitate cosmetic and functional recovery of the patient. In particular, they promote healing in radiation-recurrent oral cancer and represent a definitive form of management for established radionecrosis of the mandible. The large volume of tissue available with iliac crest osteocutaneous grafts permits the management of patients with extensive cancer involving the skin, mucosa, and bone, but cancer control may still be disappointing and there is a need for improved adjuvant chemotherapy protocols. This ...

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT We address the problem of angular momentum transport in stellar radiative interiors with a novel semi-analytic spectral technique, using an eigenfunction series expansion, that can be used to derive benchmark solutions in hydromagnetic regimes with very high Reynolds number (107-108). The error arising from the truncation of the series is evaluated analytically. The main simplifying assumptions are the neglect of meridional circulation and of non-axisymmetric magnetic fields. The advantages of our approach are shown by applying it to a spin-down model for a Formula Not Shown main-sequence star. The evolution of the coupling between core and envelope is investigated for different values of the viscosity and different geometries and values of the poloidal field. We confirm that a vi...

International Nuclear Information System (INIS)

A Quantitative Computed Tomography (QCT) method, simplifying the well-known technique proposed by Genant (1982) and applied to a standard third generation whole body CT scanner is described. This technique was applied in the measurement of the trabecular bone which has high sensitivity for metabolic changes. The BMC (Bone Mineral Content) measured in different groups of subjects (healthy postmenopausal patients versus women with postmenopausal osteoporosis) showed a highly significant difference (p<0.001). The precision of repositioning (coefficient of variation 1.8% to 2.3%, obtained in healty male patients) and the good, linear relationship computed from the phantom values, minimize measurement errors. Since this method is quickly applied and involves low-dose radiation-exposure, it could be introduced in the clinical study of metabolic bone diseases.

Science.gov (United States)

X-ray diffraction offers a unique combination of advantages for kinetic study which include the non-destructive nature of the measurement, the use of bulk crystals, and the convenience of the experimental arrangements. These attributes and the availability of position-sensitive detectors and high-flux synchrotron radiation sources make this technique most useful for in situ, dynamical investigations. When using diffraction techniques to determine a diffusion coefficient, the principle of analysis entails a scattering theory and a kinetic model. The former allows the kinetic parameter(s) to be extracted from measured intensity, while the latter relates the kinetic parameter(s) to the diffusion coefficient(s). Three examples are demonstrated: (1) Palladium Silicide (Pd{sub 2}Si) Layer Growth on Silicon, (2) Decomposition of an Ni-12.5at%Si Superalloy, and (3) Short-range Ordering in Cu-Au Solid Solutions.

International Nuclear Information System (INIS)

In the context of radiation protection for both workers and the population in general, natural sources of radiation, and in particular radon gas and its short-life decay products assume great importance. In particular, workers in thermal spas can easily be exposed to a level of radon radiation and its decay products comparable to those in uranium mines, though often these workers are unaware of the danger. The main source of radon in thermal baths is the thermal water itself, coming as it often does from deep springs, and this can produce high radon concentrations which are left in those areas in which therapy is carried out. Another factor which cannot be overlooked is the radioactive content of thermal mud, often matured for long periods by contact with thermal water. Thermal cures, though varying slightly from site to site, consist principally of mud cures, hydro-therapy and inhalation in various forms. Both health ...

International Nuclear Information System (INIS)

A technique of producing radioactive isotopes of rare earth elements (r.e.e.) and carrier free "2"4"2Am is suggested. The technique makes use of ''sandwich'' phthalocya=- nine complexes of r.e.e. and americium placed on sorbent. This is a new type of r.e.e. compounds and actinides (C_3_2H_1_6N_8)_2M (M is a metal ion) which are thermally, radiationally and chemically stable, dissolve well in some organic solvents and do not dissolve in water. Radiation and chemically stable activated carbon is used as a sorbent carrier. After irradiation the target is treated by a weakly acid solution or complex-former solution. Radioactive atoms formed due to (n, #gamma#)-reaction and desoleting the complex because of recoil transfer into the solution. When irradiating in the flux of 10"1"3 neutr./cm"2 x s for 1 hour it is possible to produce radioactive isotopes with the yield from 20 to 90%, for example "1"6"0Tb, ...

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 quality, however, ...

British Library Electronic Table of Contents (United Kingdom)

This work is concentrated on growth, spectroscopy and laser performance of thulium-doped vanadate crystals. At the beginning the growth techniques are analyzed and then the matrix of vanadates crystal, its structure and physicochemical properties are explained together with the rare earth activators influence. Detailed spectroscopy of the thulium-doped vanadate crystals then follows. On the background of this theoretical analysis and state of the art of the subject the description of thulium vanadate lasers (especially Tm:YVO"4, Tm:GdVO"4, and Tm:LuVO"4) together with their generated output radiation characteristics are presented.

International Nuclear Information System (INIS)

Advances in the diagnosis of Ewing's sarcoma of the rib were considered and retrospective analysis of the treatment of 32 patients (76% of them were children at the age of 10-15 y.o.) in the clinic of children oncology was performed. It was shown that the diagnosis of Ewing's sarcoma of the rib in children ought to be combined taking into account the course, morphology and radiation examination techniques. Most optimum treatment consisted of combined therapy (cyclic polychemotherapy, lesion focus irradiation at the summary focus dose of 57 Gy, surgery with subsequent polychemotherapy for not less than 1.5 years

Energy Technology Data Exchange (ETDEWEB)

This paper presents fundamental researches based on the electronic structure calculations and X absorption spectroscopy, allowing the knowledge on nuclear fuels at an atomic scale. They bring a better understanding of these material behavior to accurate the macroscopic simulation. The calculation methods, the experimental techniques of validation and the ab initio calculations results are detailed. (A.L.B.)

International Nuclear Information System (INIS)

The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral Pd/sub 58.8/U/sub 20.6/Si/sub 20.6/ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 A-circle.

International Nuclear Information System (INIS)

The utilization of the Ellis-formula for the determination of the tolerance of normal connective tissue is described. Beyond this, the formula is adapted to so-called critical organs. The individual suppositions implicated by the Ellis-formula are commented. Because of the verifyable congruency of the Ellis-formula with data obtained in clinical practice also by other authors, this conception is presented for the provisional determination of the limits of tolerance of normal tissue together with a computerized programme elaborated for use in different therapeutic techniques. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A gamma-ray spectrometer (GRS) has been built and delivered to the Mercury MESSENGER spacecraft which launched on August 3, 2004, from Cape Canaveral, Florida. The GRS, a part of seven scientific instruments on board MESSENGER, is based on a coaxial high-purity germanium detector. Gamma-ray detectors based on germanium have the advantage of providing excellent energy resolution, which is critical to achieving the science goals of the mission. However, germanium has the disadvantage that it must operate at cryogenic temperatures (typically {approx}80 K). This requirement is easy to satisfy in the laboratory but difficult near Mercury, which has an extremely hot thermal radiation environment. To cool the detector, a Stirling cycle mechanical cooler is employed. In addition, radiation and conduction techniques a are used to reduce the GRS heat load. Before delivering the flight sensor, a complete thermal prototype was built ...

International Nuclear Information System (INIS)

We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be ...

Energy Technology Data Exchange (ETDEWEB)

Tetracycline is an antibiotic that absorbs ultraviolet light at 355 nm and preferentially binds to atherosclerotic plaque both in vitro and in vivo. Tetracycline-treated human cadaveric aorta was compared with untreated aorta using several techniques: absorptive spectrophotometry; and tissue uptake of radiolabeled tetracycline, which showed 4-fold greater uptake by atheroma than by normal vessel. In addition, intravenous tetracycline administered to patients undergoing vascular surgery demonstrated characteristic fluorescence in surgically excised diseased arteries. Because of tetracycline's unique properties, the authors exposed tetracycline-treated and untreated aorta to ultraviolet laser radiation at a wavelength of 355 nm. They found enhanced ablation of tetracycline-treated atheroma compared with untreated atheroma. The plaque ablation caused by ultraviolet laser radiation was twice as extensive in ...

International Nuclear Information System (INIS)

For ages, herbs have been used as medicine and food. Nowadays, the interest in phytotherapeutics is increasing as well as the consumer attention. Some biochemical compounds synthesized by plants as alkaloids, phenolics, flavonoids, essential oils, tannins and vitamins, influence the composition of these plant pharmacologicals, which may produce various reactions in the human body. The microbial contamination in these raw plant materials is common, and the radiation processing is one appropriate technique for the reduction of microorganism. In herbs used as food products, the changes in total #beta#-carotene and flavonoids upon the radiation treatment were tested. The powdered and dehydrated herbs were irradiated with "6"0Co gamma rays applying doses of 0, 10, 20 and 30 kGy. The botanical species investigated were rosemary (Rosmarinus officinalis Linne), watercress (Nasturtium officinale R. Br), artichoke (Cynara scolymus ...

CERN Document Server

The aim of this work was to study the possibility of producing a fast switching optical thin film device to react to laser radiation in the visible/near infrared region of the spectrum. The switching mechanism was to be thermally driven. A computer program was written to enable the effects of changes of the refractive index of a component of a multilayer thin film stack to be modelled. Attempts to use the phase transition in vanadium dioxide were unsuccessful because, in the spectral region of interest, the 'open-state' absorption was too great. A class of materials known as 'the bronzes' was identified as being potentially useful. Attempts were made to produce thin films of bronze compounds of vanadium, tungsten and molybdenum by the techniques of conventional thermal evaporation and laser ablation for further studies. The former technique appeared to suffer from problems of decomposition of the source material. The latter ...

Energy Technology Data Exchange (ETDEWEB)

The optically stimulated luminescence (OSL) results a highly appropriate dosimetric technique for readings of absorbed radiation 'in alive' and 'in situ', as well as in real time. The CVD diamond on the other hand presents excellent qualities like radiation reader thanks to its reproducibility, radiation resistance, biocompatibility and non toxicity. The present work studies the answer of two diamond films pure and polluted with nitrogen (750 ppm) grown by the Chemical Vapor Deposition method (CVD) on silicon substrate (001) irradiated with beta (Sr-90) in the 0.833-100 Gy interval. The optical stimulation was carried out by 40 seconds with infrared laser (830 nm, 0.36 W/cm{sup 2}) and the filter BG-39 (300-600 nm) coupled the PM. The intensity and the decay of the hyperbolic type of the LOE curves were similar in both samples, for the non doped diamond were observed ...

Energy Technology Data Exchange (ETDEWEB)

The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance ...

Energy Technology Data Exchange (ETDEWEB)

Pretreatment of brown coal in oil was conducted using 1-methyl naphthalene or mixture of tetralin and 1-methyl naphthalene as solvent at temperatures ranging from 300 to 430{degree}C under nitrogen atmosphere. Effects of the solvent properties on the structural change of oxygen-functional groups (OFG) and coal liquefaction were investigated by means of quantitative analysis of OFG and solid state {sup 13}C-NMR measurement. When hydrogen transfer from solvent was insufficient, it was suggested that brown coal molecules loose their hydrogen to be aromatized. While, at lower temperatures ranging from 300 to 350{degree}C, hydrogen contained in brown coal molecules was consumed for the stabilization of pyrolytic radicals, and the deterioration of liquefaction was not observed. When hydrogen transfer from solvent was insufficient at higher temperatures above 400{degree}C in nitrogen atmosphere during pretreatment in oil, crosslinking like benzofuran type was formed by ...

Energy Technology Data Exchange (ETDEWEB)

One of the major scientific and technological challenges for the production of flexible organic electronic devices is the device protection against atmospheric molecule permeation, which causes corrosion reducing its operation and lifetime. In this work, Spectroscopic Ellipsometry has been implemented to investigate the influence of silicon dioxide nanoparticles on the optical properties of hybrid polymers. The spectra analysis revealed valuable information about the electronic and vibrational response as well as the cross-linking mechanisms of these materials. The correlation of the optical properties with the synthesis parameters and the barrier response will contribute towards their optimization in order to be used as high barrier coatings for flexible organic electronics applications.

UK PubMed Central (United Kingdom)

Abstract The authors provide a survey of how images are used in radiation therapy to improve the precision of radiation therapy plans, and delivery of radiation treatment. In contrast...Full Text Available

Environmental Research Database

No further description is available

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 ...

International Nuclear Information System (INIS)

Stereotactic radiosurgery (SRS) precisely delivers high-dose radiation to a small target (usually less than 3-4 cm in diameter), in a single session with steep dose-fall, employing various radiation methods. SRS provides good tumor control for small brain metastases from various primary cancers, with minimal untoward effects on surrounding normal brain. This excellent tumor control prevents neurological death and maintains good activity of daily life. Although surgery with whole-brain radiation therapy (WBRT) remains an important option for patients with a solitary brain metastasis, SRS with or without WBRT should be considered in patients with a limited number of small tumors and a good prognosis. Many reports, as well as both retrospective and prospective reviews, have shown WBRT before or after SRS to improve local control and reduce new distant lesion emergence. However, upfront WBRT does not improve survival. There are ...

Energy Technology Data Exchange (ETDEWEB)

This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted polymers obtained by ...

International Nuclear Information System (INIS)

Development of food preservation and processing techniques by radiation was performed. Gamma irradiation at 2-10 kGy is considered to be an effective method to control pathogenic bacteria in species including Escherichia coli O157:H7. Gamma irradiation at 5 kGy completely eliminated pathogenic bacteria in beef. Gamma irradiation at such doses and subsequent storage at less than 4 deg C could ensure hygienic quality and prolong the microbiological shelf-life resulting from the reduction of spoilage microorganisms. Gamma irradiation on pre-rigor beef shortens the aging-period, improves tenderness and enhances the beef quality. And, a new beef processing method using gamma irradiation, such as in the low salt sausage and hygienic beef patty was developed. Safety tests of gamma-irradiated meats(beefs: 0-5 kGy; porks: 0-30 kGy) in areas such as genotoxicity, acute toxicity, four-week oral toxicity, rat hepato carcinogenesis and the anti oxidative ...

International Nuclear Information System (INIS)

Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN code. ANISN is a one dimensional ...

Energy Technology Data Exchange (ETDEWEB)

A thermal-resistant radiation sensing system using optical fiber has been developed. The system is for monitoring progress of chemical decontamination and able to measure the gamma-ray level in a hot solution of decontamination chemicals in situ. Our sensor head makes use of thermal-resistant NaI (T1) and it is connected to an optical fiber bundle. Scintillation photons pass from the NaI (T1) into the end of the bundle. This part of the system can withstand temperatures of over 100degC. At the far end of the optical fiber bundle, the scintillation photons are converted into fluorescent photons using a wavelength-shifting fiber. These photons are transferred to a distant photomultiplier tube through two thin transparent optical fibers. Furthermore, we propose a self-compensation technique for the dependence of scintillator sensitivity on. This compensation method is based on the correlation between temperature, sensitivity, and scintillation ...

International Nuclear Information System (INIS)

Upgrading of oil palm empty fruit bunch (EFB), which is a main by-product of palm oil industry, to animal feeds by radiation pasteurization and fermentation was investigated for recycling the agro-resources and reducing the environmental pollution. The following results were obtained: 1) The necessary dose for pasteurization of EFB contaminated by various microorganisms including aflatoxin producing fungi was determined as 10 kGy. The chemical and biological properties of EFB were changed little by irradiation up to 50 kGy. 2) In the fermentation process, Pleurotus sajor-caju was selected as the most effective fungi and the optimum condition for fermentation was clarified. The process of fermentation in suspension was also established for the liquid seed preparation. 3) The digestibility and nutritional value of fermented products were evaluated as ruminant animal feeds and the mushroom can be produced as by-product. 4) The pilot plant named Sterifeed was built at ...

International Nuclear Information System (INIS)

recycling of waste polypropylene (WPP) and waste rubber (WR) originated from rejected worn-out tires present very important problem due to their huge amount and their negative impact on environment. many communities in the world are struggling with this problem of how to manage waste disposal, in order to eliminate or reduce waste rubber from the environment and to reduce costs of some rubber and polypropylene articles. trials to reuse waste rubber and waste polypropylene, have encountered some difficulties.such two substrate polymers differ from each other in nature, since waste polypropylene is thermoplastic while waste rubber exists in thermosetting state. accordingly, the study and use of their mixtures should be very interesting.the aim of this work is to modify the physical and chemical properties of WR and WPP each in the form of powder (120,80 mech size), through a trial to graft some vinyl comonomers onto their surfaces using gamma radiation

International Nuclear Information System (INIS)

The fundamental recommendations of the ICRP issued in its publication of 1990 stipulate the general principle of performance of dose measurements at regular intervals in the field of diagnostic radiology, for the purpose of equipment performance checking and optimization of radiological protection. In response to this requirement, the Federal Ministry, in cooperation with experts and the competent supervising authorities, has issued an order to install dose-area-product meters in angiographic examination systems, imaging systems and fluoroscopic screen devices primarily used for examining infants and children up to the age of 12. This is done in response to reported cases of adverse effects of radiation exposure and the high priority given to radiological protection in the examination of infants and children. In 1992, an expert group was convened to discuss and elaborate instructions for including dose-area product measurement in the dosimetry activities in medical ...

Energy Technology Data Exchange (ETDEWEB)

Ionising radiation induces stable free radicals in chicken bones and in the shell of chicken eggs which can be detected, by the electrons spin resonance (ESR) technique, well beyond the shelf-life of the food and can be used for dosimetry. The method usually adopted to evaluate ``a posteriori`` the dose given during the ionising radiation treatment of food, is the dose additive method. To assess the dose, the ESR signal amplitude of the irradiated food (bone or egg shell in the present case) is measured and then the dose-effect relationship is obtained by re-irradiating the sample with some additive doses (usually of 1 kGy). The dose-effect curve is back-extrapolated and the initial given dose determined. At the Istituto Superiore di Sanita (ISS), Rome, Italy, a research programme was approved two years ago aimed to, (1) study new methodological approaches for ESR dose assessment, and (2) analyse the factors which may ...

International Nuclear Information System (INIS)

In an effort to evaluate the feasibility of introducing computed radiography (FCR) into mass screening for lung cancer, the ability of FCR to detect nodules one cm in diameter was examined using a humanoid chest phantom. Based on the receiver operating characteristic (ROC) analysis, the detectability of FCR was compared with that of conventional radiography and photofluorography. The values of area under ROC curves were higher for FCR (0.963 for image similar to that with conventional film-intensifying screen system, image A; and 0.952 for processed image, image B) than the other two methods (0.774 for radiography and 0.789 for photofluorography). Degradation of image quality in FCR could be avoided by a wide latitude even if proper exposure techniques might not be employed. Images A and B in FCR yielded excellent delineation for nodules in the lung field and in the retrocardiac and subdiaphragmatic regions, respectively. This may have implications for the value of ...

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Magnesium alloys are being increasingly utilized in a variety of fields as an alternative material to organic materials and aluminum alloys, owing to excellent properties. Those include low density, and excellent damping properties. When compared to organic materials, furthermore, Mg alloy excels at recyclability, heat radiation, and electromagnetic-shielding. Though most of magnesium alloy products are manufactured through die-casting and thixo-molding at present, the demand for the expanding of magnesium wrought alloy market is increasing. Taking full advantage of a drawing technique and applying it to the conventional extruded pipe, we have developed a new type of magnesium alloy pipe. The strength of the developed pipe is significantly higher than that of the conventional one, either extruded or die-casting. Some of the excellent properties were obtained from fundamental tests performed with the developed pipe. Both tensile properties and ...

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This study presents results from Monte Carlo radiation transport calculations aimed at characterizing a novel methodology being developed to detect partial defects in Pressurized Water Reactor (PWR) spent fuel assemblies (SFAs). The methodology uses a combination of measured neutron and gamma fields inside a spent fuel assembly in an in-situ condition where no movement of the fuel assembly is required. Previous studies performed on single isolated assemblies resulted in a unique base signature that would change when some of the fuel in the assembly is replaced with dummy fuel. These studies indicate that this signature is still valid in the in-situ condition enhancing the prospect of building a practical tool, Partial Defect Detector (PDET), which can be used in the field for partial defect detection.

International Nuclear Information System (INIS)

The present article will review recent advances in focused ion beam (FIB) technology. With increasing demands for scale of integration, microfabrication technology is becoming more important and various new microfabrication tools and processing techniques are desired. FIB is one of the promising tools for future microfabrication technology. This provides maskless patterning capability, which is of importance for process simplification, nanofabrication and in the development of in situ vacuum processing. In situ vacuum processing systems are being developed by combining FIB and a molecular beam epitaxy system. Radiation damage may limit applications of FIB. However, it was demonstrated that low energy FIB (<1 keV) with very high brightness was reached and promising results for low damage processing have been obtained. (orig.).

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Hyperquenching of liquid water with cooling rates of 10{sup 6}-10{sup 7} K s{sup -1} yields glassy water. Upon {gamma}-irradiation at 77 K, the only paramagnetic species accumulating in hyperquenched glassy water are the hydroxyl and hydroperoxyl radicals. There are no hydrogen atoms or electrons seen by the ESR technique. For irradiation doses up to about 70 kGy, the relative contributions of hydroxyl and hydroperoxyl radicals to the total amount of paramagnetic species remain virtually constant. The total amount of paramagnetic species, n, is sublinear in dose, d, well approximated by n=8.55x10{sup 16}d{sup 0.8} for n in spin g{sup -1} and d in kGy.

Energy Technology Data Exchange (ETDEWEB)

As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological information is needed to predict and optimize the film's electronic, optical and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector and synchrotron radiation in two simple geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly-packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.

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)

An FEL based energy driver for Inertial Confinement Fusion (ICF) is proposed. The key element of the scheme is free electron laser system. Novel technical solutions, namely, using of multichannel, multi-stage FEL amplifier with diaphragm focusing line, reveal a possibility to construct the FEL system operating at radiation wavelength {lambda} = 0.5 {mu}m and providing flush energy E = 1 MJ and brightness 4 x 10{sup 22} W cm{sup -2} sr{sup -1} within steering pulse duration {tau} {approximately} 0.1-2 ns. Total energy efficiency of the proposed ICF energy driver is about of 11% and repetition rate is 40 Hz. It is shown that the FEL based ICF energy driver may be constructed at the present level of accelerator technique R& D.

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)

To evaluate the usefulness of portable chest radiographs by Fuji computed radiography (FCR) in ICU, FCR radiographs of 56 patients who were admitted to General Intensive Care Unit of Keio University Hospital were compared with the conventional portable images. Because FCR could show two differently processed images in one film and allowed a wide range of image reproduction, visualization of the trachea, bone soft tissues and catheters by FCR was easier than that by the conventional radiography. Repeated radiographs by FCR had similar optical densities and limited exposure errors. Furthermore, radiation was reduced than that of the conventional radiography. In conclusion, FCR is thought to be a useful technique for portable chest radiography in ICU patients. (author).

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.

International Nuclear Information System (INIS)

Under operational conditions in nuclear power plants, the carbon steel components of the primary and secondary circuits react with high temperature cooling agent forming several iron oxides and oxyhydroxides. These deposits can result in tubes' constrictions, pitting and intergranular corrosion and finally to heat transfer reducing and increasing of radiation fields around the circuits, as well. The descaling process involves the chemical dissolution of the corrosion deposits by means of diluted organic acidic solutions containing usually a carboxylic acid, a reductant and one or more corrosion inhibitors. To evaluate the removing rates of these superficial films two types of methods were used, the gravimetric and potentiodynamic techniques. By correlating the experimental results, we established the chemical composition of descaling solution and two models of mechanisms applicable to our specific conditions. (authors)

CERN Document Server

Radiation protection and the management of radioactive waste in the oil and gas industry

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The case of spontaneous radiation of channeled ultrarelativistic particles is considered when the dipolarity condition is not satisfied. The change of the particle longitudinal velocity affecting the maximum radiation frequency is included. The angular and frequency characteristics of the radiation for superhigh energies are studied for the first time. It is shown that there is an optimum energy at which the radiation density is maximum. The influence of the angle at which electrons enter a crystal and of the beam divergence on the radiation is investigated. The problem of quasichanneled particle radiation and also the radiation in axis-plane transitions are considered. (author).

International Nuclear Information System (INIS)

... odd nuclei organic compounds radiation effects radioisotopes synthesis

International Nuclear Information System (INIS)

... compounds plants radiation effects radioisotopes reaction kinetics trees

Science.gov (United States)

duced and spontaneous radiation. The amount of polarization is ... of the induced and spontaneous radiation patterns. Therefore ...

International Nuclear Information System (INIS)

A CANDU nuclear reactor was shut down for over one year because steam generator (SG) tubes had failed with outer diameter stress-corrosion cracking (ODSCC) in the U-bend section. Novel, single-pass eddy current transmit-receive probes, denoted as C3, were successful in detecting all significant cracks so that the cracked tubes could be plugged and the unit restarted. Significant numbers of tubes with SCC were removed from a SG in order to validate the results of the new probe. Results from metallurgical examinations were used to obtain probability-of-detection (POD) and sizing accuracy plots to quantify the performance of this new inspection technique. Though effective, the above approach of relying on tubes removed from a reactor is expensive, in terms of both economic and radiation-exposure costs. This led to a search for more affordable methods to validate inspection techniques and procedures. Methods are presented for ...

International Nuclear Information System (INIS)

Fission track analysis (FTA) technique for the determination of "2"3"9Pu excreted through urine has been standardized using blank samples, tracer and "2"3"9Pu spikes. Double stage anion exchange separation protocol has been applied and an average radiochemical recovery of "2"3"9Pu of 18% was obtained. An average track registration efficiency of 11 tracks per #mu#Bq of "2"3"9Pu, irradiated to 0.35x10"1"7 neutron fluence was established. Reagent blank urine samples from 11 controlled subjects were analyzed by FTA and an average of 149#+-#14 tracks was obtained. Minimum detectable activity of 34 #mu#Bq L"-"1 of urine sample was obtained and will be useful for monitoring chronic exposure cases handling MOX fuel.

International Nuclear Information System (INIS)

Low-temperature #gamma# radiolysis and photolysis of crystalline 2,4,6-triazido-3,5-dichloropyridine (TAP) were studied by means of the ESR technique. It was found that the long-term irradiation of TAP at 77 K leads to the appearance of characteristic signals of quintet 2,6-dinitreno-4-azido-3,5-dichloropyridine and 2,4-dinitreno-6-azido-3,5-dichloropyridine; the radiation-chemical yield was 0.035 and 0.012 molecule/100 eV, respectively. The photolysis of crystalline 2,4,6-triazido-3,5-dichloropyridine proceeded less effectively, producing only quintet 2,6 dinitrene with a quantum yield of #approx#4.5 x 10"-"4. The study showed that the generation of high-spin nitrenes via radiolysis of crystalline azides is much superior to the photochemical technique in efficiency and may be of practical importance for the preparation of magnetically active organic materials

International Nuclear Information System (INIS)

Thermoluminescence (TL) dosimetry was used to measure dose effects on the raw stock material of borosilicate container glass from different geographical locations. Effects were studied at times up to 60 days post-irradiation at doses from 0.15 to 20 Gy. The minimum detectable dose using this technique was estimated to be 0.15 Gy which is roughly equivalent to a 24 hr irradiation 1 cm from a 50 ng source of 60Co. Two peaks were identified in the TL glow curve, a relatively unstable peak around 125 C and a more stable peak around 225 C. Differences in TL glow curve shape and intensity were also observed for the glasses from different geographical origins. We investigate radiation induced defects in glass to further develop the technique of intrinsic dosimetry - the measurement of the total absorbed dose received by the walls of a container holding radioactive material. Intrinsic dosimetry is intended to be used as an ...

Energy Technology Data Exchange (ETDEWEB)

An updated review of the state of the art in the development of GaAs solar cells is provided, with emphasis on AlGaAs-GaAs cells suitable for space applications. A set of theoretically derived characteristics is given for this type of solar cell. Comparison of measured performance with theory shows excellent agreement. Data on the effects of radiation damage (high-energy electrons, protons, and neutrons) is also integrated into a form useful for evaluation purposes. Techniques for fabricating (AlGa)As-GaAs solar cells in quantities large enough for practical applications are discussed and are shown to have been demonstrated. The possibility of extending these techniques to the fabrication of very thin low-weight cells for space applications is also considered. Finally, the results obtained to date in the development of GaAs solar cells for applications requiring concentrated sunlight are reviewed, for terrestrial as well as ...

International Nuclear Information System (INIS)

The present article outlines major features of the free electron laser (FEL) and reviews research and development of FEL. Relations among the oscillation frequency, electron beam parameters and wiggler parameters, the physical mechanism of amplification and the physical process of saturation are discussed to identify the difference between FEL and other lasers. The report also outlines techniques for accelerators which are used to generate high-quality, high-energy electron beams required for FEL experiments. Techniques to achieve a short wavelength, high output and high efficiency, and applications of FEL are also discussed. FEL consists of an electron accelerator, wiggler and optical resonator. In FEL, electron beams with a relativistic energy interact resonantly with an electromagnetic field to generate coherent electromagnetic waves. Unlike conventional lasers, FEL does not surfer from restrictions on its oscillation frequency associated ...

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Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a {sup 60}Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts ...

Energy Technology Data Exchange (ETDEWEB)

The overall goal of the proposed project is to explore the use of partitioning tracers to characterize dense nonaqueous phase liquids (DNAPLs) in aquifer systems. Bulk-phase partitioning tracers will be investigated to detect and determine DNAPL saturation, while interface partitioning tracers will be investigated to measure the area of the DNAPL-water interface. The specific objectives that will be addressed to accomplish this goal are: (1) Investigate the use of partitioning tracers to detect and determine both the saturation and interfacial area of DNAPLs in saturated porous media. (2) Investigate the effect of rate-limited mass transfer on the transport behavior of partitioning tracers. (3) Investigate the effect of porous-media heterogeneity on the transport behavior of partitioning tracers. (4) Develop and evaluate mathematical models capable of simulating the transport of partitioning tracers in complex systems. This proposal outlines an integrated approach for the development ...

International Nuclear Information System (INIS)

We investigate the efficacy of mitigating radiation-based single event effects (SEE) within circuits incorporating SiGe heterojunction bipolar transistors (HBTs) built with an N-Ring, a transistor-level layout-based radiation hardened by design (RHBD) technique. Previous work of single-device ion-beam induced charge collection (IBICC) studies has demonstrated significant reductions in peak collector charge collection and sensitive area for charge collection; however, few circuit studies using this technique have been performed. Transient studies performed with Sandia National Laboratory's (SNL) 36 MeV 16O microbeam on voltage references built with N-Ring SiGe HBTs have shown mixed results, with reductions in the number of large voltage disruptions in addition to new sensitive areas of low-level output voltage disturbances. Similar discrepancies between device-level IBICC results and circuit measurements ...

International Nuclear Information System (INIS)

Objective: To develop a computerized method of internal dose estimation on radiation protection. Methods: Based on MIRD mathematic model of the organs and by means of the programming language of MS Visual Basic 6.0, a computer program of dose estimation in internal radiation was developed for radiation protection. Results: The computerized method of dose estimation for internal radiation was completed. Conclusions: This computerized method is very convenient for internal radiation dose estimation of several aspects. It can also be used in radiation accident. (authors)

British Library Electronic Table of Contents (United Kingdom)

Polyurethane (PU) foam was combined with protein drug-loaded pH-sensitive alginate-bentonite hydrogel for wound dressings. Alginate is a linear copolymer composed of 1?4-linked ?-D-mannuronic acid (M) and its c-5-epimer ?-Lguluronic acid (G). The amount of (M) and (G) and their sequential distribution are varied depending on the alginate source. Soluble sodium alginate can become a hydrogel when cross-linked with divalent cations and has widespread applications in the food, drink, pharmaceutical and bioengineering industries. Recently, it has been also proposed as a biomaterial for drug delivery systems. Bentonites are the natural inorganic polymers consisting of a large proportion of expandable clay minerals with a three-layer structure such as montmorillonite, beidellite, nontronite, etc...

British Library Electronic Table of Contents (United Kingdom)

A novel composite charged mosaic membrane (CCMM) was prepared via interfacial polymerization (IP) of polyamine [poly(epichlorohydrin amine)] and trimesoyl chloride (TMC) on the polyethersulfone (PES) support. Fourier transform infrared spectroscopy (FT-IR), environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM) and water contact angle analysis were applied to characterize the resulted CCMM. The FT-IR spectrum indicates that TMC reacts sufficiently with polyamine. ESEM and AFM pictures show that the IP process produces a dense selective layer on the support membrane. The water contact angle of the CCMM is smaller than that of the substrate membrane because of the cross-linked hydrophilic polyamine network. Several factors affecting the IP reaction and the performan...

British Library Electronic Table of Contents (United Kingdom)

New nanofibers containing poly(vinyl pyrrolidone)-iodine complex (PVP-iodine) were obtained by electrospinning in order to prepare materials suitable for wound dressings. Different approaches were used: a one-step method based on electrospinning of PVP-iodine or poly(ethylene oxide)/PVP-iodine solutions and a three-step method based on electrospinning of PVP or poly(ethylene oxide)/PVP mixed solutions followed by photo-mediated crosslinking of the obtained nanofibers and subsequent complexation with iodine. The average diameters of the fibers were in the range 150-470nm depending on the composition and on the applied field strength (AFS) and increased with increasing the amount of PEO in the spinning solutions. Higher AFS resulted in greater fiber diameter and in size distribution broadeni...

Science.gov (United States)

Explicitly defining virtual collections in a digital library can benefit both users and contributors. This paper outlines the costs and benefits for defining virtual collections and describes an implementation of collection-level metadata in two digital libraries. Our work suggests that component repositories of NSDL would profit by describing their collection, and sub-collections, using a schema such as the one we implemented. This would enable NSDL to provide a rich, cross-linked hierarchy of virtual collections. By sharing collection-level, rather than item-level, metadata, collections would provide detailed resource information, presumably keeping most of their viewership, while NSDL would provide a broad description of resources.

Energy Technology Data Exchange (ETDEWEB)

Gel dosimetry is a new dosimetry method applied in radiation therapy. Gel dosimeters consist of a radiation sensitive gel, which can integrate absorbed doses from several radiation sources or beams. The dose to the gel can be evaluated by magnetic resonance imaging (MRI), a procedure that is the focus of the present thesis. A robust tool for the evaluation of the nonuniformity in MRI has been developed, the Deviation Image method. Unlike previously presented methods, the Deviation Image method includes all nonuniformity variations across a phantom surface and is insensitive to stochastic noise. Methods for the estimation of stochastic noise were analyzed in terms of sensitivity to nonuniformities. A method that averages the stochastic noise level over five regions over the phantom surface, and a method that assesses the stochastic noise level from the background, were found to be the methods of choice. Pronounced MR image ...

International Nuclear Information System (INIS)

Full text: Founded in 1964, Ankara Nuclear Research and Training Center (ANRTC) conducts and facilitates the scientific activities including training (summer practice, MSc and Ph D studies in physics and chemistry, IAEA fellowship programs etc.), research and other studies in nuclear and related fields. As it's a part of main duties, ANRTC has analysis on the variety of samples, and radiation protection services commercially, for radiation workers in state, public and private sectors. Research, development and application projects implemented in this Center have mostly been supported by State Planning Organization (SPO) and Turkish Atomic Energy Authority (TAEA). In addition to the projects there are on going collaborative studies with some national Universities and International Atomic Energy Agency. The main activities carried out in ANRTC can be summarized as: studies on experimental nuclear physics, application of nuclear ...

International Nuclear Information System (INIS)

The sterile insect release technique can often be improved by removal of females before release. Rearing efficiencies can also be increased if removal of the females occurs at early developmental stages. In order to begin to develop genetic sexing strains for the pink bollworm, Pectinophora gossypiella (Saunders), it was necessary to determine the best dosage of radiation for induction of viable sex linked recessive lethal mutations and to see if stocks containing induced sex linked lethals could be maintained in culture. Sex linked recessive lethal mutations can be detected by distorted sex ratios in the progeny of treated adults. However, in the pink bollworm, highly distorted sex ratios are common even in the absence of induced mutations. Therefore, a visible sex linked trait, purple eye, was used as a marker for the untreated X-chromosomes in crosses. Thus, the presence of a recessive sex linked lethal mutation induced by the ...

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Land surface parameterization schemes such as the Simple Biosphere Model (SiB2) have found considerable use in climate simulation models, where they provide lower boundary conditions in the form of surface sensible and latent heat fluxes. A methodology is described to apply models of this type at high resolution, using data from the Department of Energy{close_quote}s Cloud and Radiation Testbed in Oklahoma and Kansas, to determine the spatial variations of heat fluxes over the domain and to determine area-weighted flux averages for use in single-column model studies. Data from a dense array of meteorological instruments are interpolated to provide the wind, temperature, vapor pressure, radiation, and precipitation values needed by SiB2. The state of the vegetation is characterized through the use of the normalized difference vegetation index determined from satellites. The performance of the SiB2 model is evaluated by comparing its predictions ...

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)

Consensus reached in the last few years that fourth generation light source will most likely be a X-ray or a UV coherent source based on single-pass high-gain free electron laser (FEL), such as Self Amplified Spontaneous Emission (SASE), or seeded high-gain harmonic-generation (HGHG) free electron lasers. High-gain (>10"7) required for single-pass FEL puts great constrain on the quality of electron beam, and demands detailed distribution information of electron beam in six-dimension. The typical accelerator system for single-pass FEL consists of a photocathode RF gun injection system, a linac and magnetic bunch compressors, and a long undulator. The major challenges in beam diagnostics for single-pass FEL are to characterize the pico-seconds high-brightness electron beam in six-dimension produced by photocathode RF gun injector, and improve the stability and reliability of the photocathode RF gun injection system. Characterization of short electron bunch (#approx#100 fs) produced by ...

CERN Document Server

Lithography Production Techniques for next Generations of Microelectronics

Science.gov (United States)

Not Available

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.

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No abstract prepared

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

Cancer and Tobacco Abuse

International Nuclear Information System (INIS)

Microdamage naturally occurs in bone tissue as a result of cyclic loading placed on the body from normal daily activities. While it is usually repaired through the bone turnover process, accumulation of microdamage may result in reduced bone quality and increased fracture risk. It is unclear whether certain areas of bone are more susceptible to microdamage than others due to compositional differences. This study examines whether areas of microdamaged bone are chemically different than undamaged areas of bone. Bone samples (L3 vertebrae) were harvested from 15 dogs. Samples were stained with basic fuchsin, embedded in poly-methylmethacrylate, and cut into 5-(micro)m-thick sections. Fuchsin staining was used to identify regions of microdamage, and synchrotron infrared microspectroscopic imaging was used to determine the local bone composition. Results showed that microdamaged areas of bone were chemically different than the surrounding undamaged areas. Specifically, the mineral ...

International Nuclear Information System (INIS)

This text-book (electronic book - multi-media CD-ROM) constitutes a course-book - author's collection of lectures. It consists of 13 lectures in which the reader acquaints with the basis of radiobiology: Introduction to radiobiology; Physical fundamentals of radiobiology; Radiation of cells; Modification of radiation damage of cells; Reparation of radiation damage of cells; Radiation syndromes and their modification; Radiation injury; Radiation damage of tissues; Effect of radiation on embryo and fetus; Biological effects of incorporated radionuclides; Therapy of acute irradiation sickness; Delayed consequences of irradiation; Radiation oncology and radiotherapy. This course-book may be interesting for students, post-graduate students of chemistry, biology, physics, medicine as well as for teachers, scientific workers ...

Science.gov (United States)

Cervical Cancer; Radiation Toxicity

International Nuclear Information System (INIS)

... beam monitoring betatrons delay circuits errors fluctuations gamma radiation

International Nuclear Information System (INIS)

On the basis of legally provided area dose measurements and time records of fluoroscopic examinations during the operation, radiation doses to medical personnel and patients are evaluated. Adequate radiation protection measures and a careful behaviour in the operating room keep the radiation exposure to the personnel below the maximum permissible exposure. Taking into account the continuous personnel radiation monitoring and medical supervision, radiation hazards in the operating room can be considered low.

International Nuclear Information System (INIS)

Early effects of 100 Kilorads of X-rays on muscle cell membrane properties have been measured in sartorius muscles from Leptodactylus ocellatus. Threshold strength for rectangular current pulses increased 10% after irradiation, and action potential propagation velocity decreased 10%. Passive membrane parameters were calculated from potential responses to sub-threshold current pulses, assuming conventional cable theory. Specific membrane conductance increased to 18% after irradiation, membrane capacitance increased 14%, and length constant decreased 10% but membrane time constant was unchanged. Cell diameter decreased 5%, and resting membrane potential decreased 8%. Membrane parameters during an action potential were also evaluated by the phase-plane and current-voltage plot techniques. Irradiation significantly decreased the action potential amplitude, the excitation potential, and the maximum rates of rise and fall of membrane potential. Increases were observed in ...

International Nuclear Information System (INIS)

Development of techniques for separating isomeric nuclides is important to the investigation of schemes for gamma-ray lasers. In preparation for an experiment to separate 10_1_4 atoms of the /sub 197m/Hg (299 keV, tau/sub 1/2/ = 24 hours) isomer, we report isotopically selective resonance ionization of mercury atoms. This has been accomplished by three-step excitation via the 6_3P"1 and 8_1S"0 excited states, using three collinear pulsed laser beams of 254, 286, and 532 nm wavelengths from a Nd:YAG and two dye lasers. These beams were passed through a closed mercury-vapor cell containing electrostatic plates to which the ions were drawn. Ion current and fluorescent radiation were measured as a function of laser frequency. Hyperfine structures for the 254- and 286-nm transitions were observed.

International Nuclear Information System (INIS)

The Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI-2 Reactor Building during February and March 1982 and was designed to investigate the effectiveness of various surface decontamination techniques. The polar crane, D-rings, missile shields, refueling canal, fueling bridge, major equipment, floors and some walls were flushed with low pressure water. Water lances were directed manually and applied water at temperatures between ambient and 60"0C at a flow rate of about 95 liters per minute. In addition, floor surfaces on the 305-ft elevation and floor surfaces and major equipment on the 347-ft elevation were sprayed with high pressure water (floors in the Reactor Building are designated by their elevations above sea level). The water pressure in this case varied between 13.8 and 41.4 mPa and water temperature was at a maximum 60"0C. Certain surfaces were also decontaminated using either strippable coatings or a mechanical ...

International Nuclear Information System (INIS)

The UK Energy Research Centre (UKERC) in it's submission to the DTI's 2006 Energy Review reminded us that the 'UK has abundant wind, wave and tidal resources available; its mild climate lends itself to bio-energy production, and solar radiation levels are sufficient to sustain a viable solar industry'. These technologies are at different stages of development but they all draw on basic and applied Science and Engineering. The paper will briefly review the renewable energy technologies and their potential for contributing to a sustainable energy supply. Three research topics will be highlighted that bridge the gap between the physics underpinning the energy conversion, and the engineering aspects of development and deployment; all three are highly relevant to the Government's programme on micro-generation. Two are these are taken from field of thin film photovoltaics (PV), one related to novel device development and the other to a measurement ...

CERN Document Server

Measurement of redshifted 21-cm emission from neutral hydrogen promises to be the most effective method for studying the reionisation history of hydrogen and, indirectly, the first galaxies. These studies will be limited not by raw sensitivity to the signal, but rather, by bright foreground radiation from Galactic and extragalactic radio sources and the Galactic continuum. In addition, leakage due to gain errors and non-ideal feeds conspire to further contaminate low-frequency radio obsevations. This leakage leads to a portion of the complex linear polarisation signal finding its way into Stokes I, and inhibits the detection of the non-polarised cosmological signal from the epoch of reionisation. In this work, we show that rotation measure synthesis can be used to recover the signature of cosmic hydrogen reionisation in the presence of contamination by polarised foregrounds. To achieve this, we apply the rotation measure synthesis technique to ...

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Digital imaging techniques such as Digital Image Intensifier Radiography and Digital Storage Phosphor (Selenium) Radiography are replacing conventional film-screen radiography more and more. The aim of this development is the extension of diagnostic capabilities and the reduction of side effects such as radiation dose. Conventional film-screen radiography and digital radiography are very different ways of imaging. For digital radiography specific post-processing is the link between imaging conditions and film documentation. Optimisation of the images includes new possibilities of post-processing and a broad range for variation of the dose. Especially in fluoroscopy, dose can be reduced significantly by new technical features like pulsed fluoroscopy. For digital radiography the European guidelines on quality criteria have to be applied to projection radiography, digital subtraction radiography and to fluoroscopy. Further work should lead to a ...

Energy Technology Data Exchange (ETDEWEB)

Since 1958, the AlliedSignal Federal Manufacturing and Technologies (FM and T) Metrology Department has developed measurement technology and calibration capability in four major areas of measurement: mechanical; environmental, gas, liquid; electrical (D.C., A.C., RF/microwave); and optical and radiation. The capabilities developed include unique capabilities in many areas of measurement and engineering expertise to develop measurement techniques and resolve measurement problems in these major areas. FM and T Metrology was established in 1958 to provide a measurement base for the Department of energy`s Kansas City Plant. The Metrology Engineering Department provides the expertise to develop measurement capabilities for virtually any type of measurement which falls into the broad areas listed above. The engineering staff currently averages almost 16 years of measurement experience. A strong audit function has been developed to provide a means to ...

International Nuclear Information System (INIS)

A pilot project was started in 1977 over the Lake Superior basin to measure water storage on the land area using aerial gamma-ray spectrometry to provide hydrologic information for forecasting inflow to the lake. Two airborne surveys were made, respectively in November 1977 and March 1978 which provided estimates of the increase in snow water equivalent between these surveys. The basin is located on the Canadian Shield and consequently, the gamma radiation count rate is quite variable. The airborne results are compared with ground measurements on selected flight lines and show generally good agreement. Two equipment calibrations in the Ottawa area provided inconsistent parameter values which are consequently also reflected in the results over the Lake Superior basin. The project has demonstrated to-date that the technique can be developed into an operational system for measuring snow cover water equivalent of this vast and remote area by using ...

International Nuclear Information System (INIS)

The transport properties of a 'thin' polycrystalline diamond film are analyzed after the sample exposure to 8.06-keV x-ray radiation. Structure and morphology of the as-grown film have been evaluated by Raman, x-ray diffraction, and scanning electron microscopy techniques. The transport properties have been investigated by measuring dark current-voltage characteristics in the temperature range of 60 to 360 K. Ohmic transport has been evidenced on the as-grown film up to 1.16x10"5 V/cm. After irradiation, nonlinear contributions to the dark current have been evidenced and related to field-assisted thermal ionization of traps. Below 200 K, hopping mechanisms have been observed. Correlations have been found among x-ray irradiation, density of traps involved in the transport processes, and the nonhomogeneous nature of the sample. A simple model of the grain boundary structure is proposed to explain the observations.

International Nuclear Information System (INIS)

The principle and history of free-electron laser (FEL), first evidenced in 1977, the relationship between FEL wavelength and output power, the high-power FEL driven by the superconducting linac, the X-ray FEL by the linac, and the medical use are described. FEL is the vacuum oscillator tube and essentially composed from the high-energy linac, undulator and light-resonator. It utilizes free electrons in the vacuum to generate the beam with wavelength ranging from microwave to gamma ray. The first high-power FEL developed in Japanese Atomic Energy Research Institute (JAERI) is based on the development of superconducting linac for oscillating the highest power beam. In the medical field, applications to excise brain tumors (in US) and to reconstruct experimentally blood vessels in the pig heart (in Gunma University) by lasing and laser coagulator are in progress with examinations to remove intra-vascular cholesterol mass by irradiation of 5.7#mu#m FEL beam. Cancer cells are considered ...

International Nuclear Information System (INIS)

Volatile compounds produced in flexible food packaging materials (LDPE, EVAc, PET/PE/EVOH/PE) during electron beam irradiation were isolated by purge and trap technique and identified by combined gas chromatography-mass spectrometry (GC/MS), after thermal desorption and concentration. For comparison purposes non-irradiated films were also studied. Film samples were irradiated at low (5 kGy, corresponding to cold pasteurization), intermediate (20 kGy, corresponding to cold sterilization) and high (100 kGy) doses. It was observed that a number of volatile compounds are produced after irradiation in all cases. Furthermore the amounts of all volatile compounds increase with increasing irradiation dose. Both primary (methyl-derivatives etc.) as well as secondary i.e. oxidation products (ketones, aldehydes, alcohols, carboxylic acids etc.) are produced upon irradiation. These products may affect organoleptic properties and thus shelf-life of prepackaged irradiated foods. ...

International Nuclear Information System (INIS)

As yet, the role of Computed Tomography (CT) as a routine imaging technique in the staging and follow-up of thoracic Hodgkin's disease has not been assessed. The authors reported the results obtained in 120 patients affected with thoracic Hodgkin's disease, staged and followed by means af chest X-rays and CT. CT better identified intrathoracic involvement of mediastinal nodes, of lung parenchyma, of pleura, and of pericarcial and chest walls in 54/120 patients (45%), with staging modifications in 18 (15%) of them only. Treatment was changed only in 12 patients (19%) where radiation therapy had been planned. The clinical value of the additional information yielded by CT was especially evident in the follow-up: CT allowed the correct evaluation of persistent/ recurrent disease in 51/117 patients (43.5%), a figure high enough to suggest the use of CT in the routive follow-up of patients affected with thoracic Hodgkin's disease.

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In portal images with high energy X-ray (10 MV), it is sometimes difficult to verify the irradiation field because of the low contrast. Especially, in the abdominal and pelvic region, the deterioration of portal image quality is remarkable. To solve this problem, we took portal images using computed radiography (FCR). Also, we develop a technique in which a copper plate (3 mm) and lead foil (0.3 mm) are closely set in the front and rear of the photostimulable phosphor plate (imaging plate), for increased energy absorption. As a result, image quality was very high and we confirmed image improvement using observer performance experiments. We made a special cassette which can closely set metallic plates to imaging plate and load FCR-7000 directly. Therefore, image process becomes simple, and suitable for routine work. In computed radiography, image processing (tone scale modification and edge enhancement) is possible, and is advantageous portal imaging. When PACS is ...

International Nuclear Information System (INIS)

Methods: Systemic irradiation of neuroaxis is an essential part in the management of medulloblastoma, stPNET and intracranial germ cell tumors. The introduction of quality assurance programs in radiooncology assures a precise radiotherapy of target volumes and is a prerequisite to improve survival. Results: Hyperfractionated radiotherapy has the potential of increasing dose to tumor more safely without increasing the risk for late adverse effects. Pilot studies revealed excellent tumor control in medulloblastoma with acceptable acute toxicity and a long-term survival of up to 96%. In medulloblastoma stereotactic radiation techniques reveal an acceptable toxicity and promising results in tumor control in recurrent disease or as primary treatment. They are now part of future treatment protocols in case of persisting residual tumor. Radiotherapy alone in pure germinoma is continuously yielding high cure rates. In secreting germ cell tumors ...

International Nuclear Information System (INIS)

In the radiochemical reprocessing of spent fuel from nuclear reactors, a considerable amount of liquid, solid, and gaseous waste is formed; this waste is potentially dangerous to humans and requires the development of special and complex technological techniques for its localization and reliable long-term storage. The most hazardous are liquid wastes of high specific activity - water-tailings solutions obtained in the first cycle of extraction after the removal of uranium and plutonium. These solutions contain more than 99.9% of all the other transuranic elements - isotopes of neptunium, americium, and curium. Where necessary, some fission products and actinides may be removed from wastes of high specific activity for subsequent use. The quantity, composition, and activity of these wastes varies within broad limits, depending on the type and power of the reactor, the initial nuclide composition of the fuel, and its specific energy yield, the regeneration ...

Energy Technology Data Exchange (ETDEWEB)

The atmosphere and the biosphere are inherently coupled to one another. Atmospheric surface state variables such as temperature, winds, water vapor, precipitation, and radiation control biophysical, biogeochemical, and ecological processes at the surface and subsurface. At the same time, surface fluxes of momentum, moisture, heat, and trace gases act as time-dependent boundary conditions providing feedback on atmospheric processes. To understand such phenomena, a coupled set of interactive models is required. Costs are still prohibitive for computing surface/subsurface fluxes directly for medium-resolution atmospheric general circulation models (AGCMs), but a technique has been developed for testing large-scale homogeneity and accessing surface parameterizations and models to reduce this computational cost and maintain accuracy. This modeling system potentially bridges the observed spatial and temporal ranges yet allows the incorporation of ...

Energy Technology Data Exchange (ETDEWEB)

The design and material characteristics of garter spring were summarized and Nondestructive detection techniques of garter spring were also described. In particular, Eddy current testing of loose type garter spring was used in Wolsung unit 1 and was described in detail. The inspection technique of tight type garter spring has not been established and all candidated techniques were investigated in order to choose the possible detection technique. Candidated nondestructive techniques including RFEC, PEC, Magnetic technique using GMR sensor, AE, Guided Wave technique, and high frequency ultrasonic technique, are summarized for evaluating the detectability of tight garter spring.

International Nuclear Information System (INIS)

The most propagated mechanisms of stimulated radiation of electron beam such as Cherenkov one-particle and collective effects, ondulator and magnetic bremsshrahlung radiations, Doppler anomalous effect, Thompson and Raman scattering and radiation are discussed. Relation of spontaneous radiation mechanisms of individual electron and stimulated radiation effects in electron beams has been elucidated, grounds of linear electrodynamics of radiative beam instabilities are stated, and main mechanisms of their nonlinear stabilization are elucidated as well. Various simulated processes in electron beams are considered from the unique point of view using a simple mathematical apparatus and such physical laws as conservation and Newton laws.

International Nuclear Information System (INIS)

An overview of different Ion Beam Analysis (IBA) techniques is given. Examples of applications of the PIXE techniques to various types of samples are presented. (author)

International Nuclear Information System (INIS)

Nitroaromatic radiosensitizers become metabolically bound preferentially to hypoxic cells and at least 10/sup 9/ adducts/cell can be tolerated as non-toxic. EMT-6 tumor cells have been incubated in hypoxia in the presence of /sup 3/H-Misonidazole and /sup 125/I-Azomycin Riboside for various times and the amount of /sup 3/H or /sup 125/I bound/cell was determined. Cells were stored as monolayers at 25"0C for up to 96 hr to accumulate radioactive decays and transferred at various times to 37"0C for colony-forming assays. No radiation inactivation was measured in cells which had incorporated at least 10/sup 6/ /sup 3/H or 10/sup 5/ /sup 125/I atoms. Previous studies had shown that -- 1% of MISO adducts to EMT-6 cells was associated with cellular DNA. These data indicate that the radiation-induced damage produced by these quantities of bound /sup 3/H or /sup 125/I causes little or not cell inactivation. The results of current studies to measure the ...

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North Carolina is in the process of siting a LLRW disposal facility as the next host state for the Southwest Compact. After two years of site characterization studies at two technically challenging sites, the LLRW Management Authority (the Authority), will submit a license application for the preferred site. One potential site is in unconsolidated Tertiary and Cretaceous deposits of the inner Coastal Plain, the other in fractured sedimentary rocks of the Triassic Deep River Basin. Involved since 1986, the North Carolina Geological Survey (NCGS) provides technical advice to the Division of radiation Protection, the state regulatory agency authorized to approve or deny a license. With the multi-million dollar project behind schedule, and millions of dollars over budget, in February 1992 the Southeast Compact Commission established three project milestones (1) submit license application by December 31, 1993; (2) approve license by March 15, 1994; (3) open facility by ...

International Nuclear Information System (INIS)

Purpose: In this paper, we present an alternative to the originally proposed technique for the delivery of spatially fractionated radiation therapy (GRID) using multi-leaf collimator (MLC) shaped fields. We employ the MLC to deliver various pattern GRID treatments to large solid tumors and dosimetrically characterize the GRID fields. Methods and materials: The GRID fields were created with different open to blocked area ratios and with variable separation between the openings using a MLC. GRID designs were introduced into the Pinnacle"3 treatment planning system, and the dose was calculated in a water phantom. Ionization chamber and film measurements using both Kodak EDR2 and Gafchromic EBT film were performed in a SolidWater phantom to determine the relative output of each GRID design as well as its spatial dosimetric characteristics. Results: Agreement within 5.0% was observed between the Pinnacle"3 predicted dose distributions and the ...

International Nuclear Information System (INIS)

Collective dose equivalent and population dose from occupational exposures in Japan, 1988 were estimated on the basis of a nationwide survey. The survey was conducted on annual collective dose equivalents by sex, age group and type of radiation work for about 0.21 million workers except for the workers in nuclear power stations. The data on the workers in nuclear power stations were obtained from the official report of the Japan Nuclear Safety Commission. The total number of workers including nuclear power stations was estimated to be about 0.26 million. Radiation works were subdivided as follows: medical works including dental; non-atomic energy industry; research and education; atomic energy industry and nuclear power station. For the determination of effective dose equivalent and population dose, organ or tissue doses were measured with a phantom experiment. The resultant doses were compared with the doses previously calculated using a chord ...

International Nuclear Information System (INIS)

Purpose/Objective: With the advent of computed tomography and magnetic resonance imaging, the three dimensional representation of the patient anatomy has become an invaluable resource for better diagnosis and delineation of the target volume and sensitive structures in radiation therapy. Although the therapeutic linear accelerator industry has made available highly sophisticated equipment, the aggressiveness in dose prescription and delivery has to be complimented by accurate dose computation methods. We have adopted a convolution/superposition algorithm for the calculation of absolute dose that fully accounts for the external shape and internal structure of the patient for photon treatment radiotherapy. In this paper, we will discuss the principles of the convolution algorithm and we will show how the computed dose compares to clinically relevant treatment techniques. Materials and Methods: A computer controlled data acquisition system and a ...

Energy Technology Data Exchange (ETDEWEB)

The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just ...

Energy Technology Data Exchange (ETDEWEB)

From 1977 through 1984, 293 previously untreated patients with biopsy proven carcinoma of the uterine cervix were treated by whole pelvis irradiation and high intensity 60Co remote afterloading (RAL) intrauterine tandem techniques in Haiti. The treatment results were analyzed retrospectively to evaluate the therapeutic results and prognostic factors of a strict protocol involving 40 Gy to the whole pelvis (2 Gy/day, 5 days/week). In addition, on the 5th day of the 3rd week, the first outpatient 60Co remote afterloading intracavitary insertion, delivering 7.5 Gy to point A with each insertion, repeated 3 times by a week separation for a total of 4 times. The total TDF for external beam plus RAL was 158 and 175 for early and late effects respectively. One hundred-four patients were evaluable after 1 year or more follow-up, with a median of 26.5 months. No evidence of disease (NED) by Stage at 1 year was: Stage I of 100% (3/3), Stage II of 82% (9/11), Stage III of 80% ...