The problem of optimizing a horn radiator of electromagnetic waves for the reflection coefficient and the coefficient of transformation of the fundamental mode into higher order modes is solved. Optimization is performed by means of selecting a combined shape of the radiator generatrices.
Chemical analyses were done on the abnormal hemoglobins of the five (101 x SEC)F_1 offspring of X- irradiated adult SEC mice to determine which hemoglobin genes were expressed in each hemoglobin variant. Three offspring of irradiated SEC males did not express either of the two kinds of #alpha#-chains normally found in all SEC mice. The deficient #alpha#-chain synthesis caused these mice to exhibit an #alpha#-thalassemia similar to human #alpha#-thalassemia. Scanning electron microscopy was used to show that many erythrocytes of mice with #alpha#-thalassemia have bizarre shapes; e.g. many erythrocytes appeared flattened or had thorny projections (acanthocytes). One mutant with a tandem duplication of a segment of chromosome 7 (site of locus determining #beta#-chain structure) produced twice as much SEC as 101 #beta#-chain polypeptides. One mutant that probably arose by non-disjunction of chromosome 7's in its unirradiated 101 mother and loss of ...
Several recent studies have documented that non-human primates can individuate objects according to property and/or kind information in much the same way as human infants do from around one year of age when they begin to acquire language. Some studies suggest, however, that only some properties are used for the individuation of food items: color, but not shape. The present study investigated whether these findings reveal a true competence problem with shape properties in the food domain or whether they merely reveal a performance problem (e.g., lack of attention to shapes). We tested 25 great apes (chimpanzees, bonobos and gorillas) in two food individuation tasks. We manipulated subjects? experience with differences in color and shape properties of food items. Results indicated (i) that a...
Secondary deuterium in the atmosphere are produced in interactions by primary cosmic rays. The shape of their energy spectrum depends on the primary cosmic ray spectrum incident at the top of the atmosphere. At high energies, the spectral shape depends on the primary spectrum of helium and heavy nuclei. However, at very low energies, specially below the geomagnetic cut-off, the spectral shape depends on the evaporation and recoil processes and hence almost independent of the spectral shape of the primary radiation. It is undertaken a calculation of the secondary deuterium spectrum at small atmospheric depths at various latitudes and the results will be presented.
Microbial population and moisture content of traditional herbal medicines contaminated with 3 kinds of aerobic microbes, packed in 5 kinds of plastic packaging materials, followed by irradiation at minimum dose of 5 kGy and stored for 6 months were investigated. The highest reduction of microbial counts during storage was observed on samples packed in polyethylene bags. All of packaging materials used were found to be impermeable to microbes and water vapour. Radiation and packaging materials used acted synergistically to inactivate microbes durind storage. The microbial counts decreased as much as 2 to 4 log cycles during storage. (author).
A new kind of e-beam bunching enabling the production of coherent spontaneous emission (CSE) is proposed and considered. It is shown that an e-beam in passing through an undulator will induce CSE along with incoherent spontaneous radiation on the same wavelength if the e-beam transverse velocity is modulated with a spatial period twice as long as the radiation wavelength. Such angular modulated beams can be regarded as alternatives to conventionally density modulated beams for CSE production. Requirements for e-beams are similar in both cases.
AbstractThe optimal definition of the size, shape and location of gross tumour volume is one of the most important steps in the planning of radiation therapy, and necessitates a proper...Full Text Available
This work deals with kinetic description of carbothermic reduction of iron oxides using microwaves as power source. Previous researches show that it is possible to conduct this kind of process successfully, but real kinetic comparisons between conventional and microwaves procedure have been presented partially. The aim of this work is to describe reduction kinetics, taking into account how the iron oxide is reduced by microwaves compared with conventional energy supply. In this study the authors used iron ore in pellet shape and dust. They found that both, pellet and dust reduction stops when it reaches approximately 40%, even at whole power.
The measurement methods of homogeneity of dispersion fuel were analyzed. The effects of mixing method, rotating speed, particle shape, particle size and moisture content on homogeneity of U{sub 3}Si/Al powder mixture were characterized by the apparent density measurement. The effects of fuel particle shape on green properties and optimum compaction conditions were investigated in U{sub 3}Si{sub 2}/Al powder compacts. 3 kinds of measurement method on the homogeneity were analyzed by apparent density measurement method, x-ray image contrast method and image analysis method of mixed powders or fuel rods. The homogeneity of dispersed fuel powder mixture was analyzed using three kinds of mixing, by apparent density measurements method. The homogeneity of powder mixture increased with rotating speed of the V-shape tumbler mixer. The comminuted irregular shaped ...
The use of gamma radiation to obtain wood-polymer composites is one of the applications of radiation that presents the most commercial interest. The process, denominated radiopolymerization, comprises the impregnation of monomers into the completely dried wood followed by exposure to gamma radiation to induce polymerization of the impregnated monomers. I this context, the present work aimed the application of this process to seven kinds of wood existing in the brazilian forests. The considered monomer is styrene and the gamma source is Cobalt-60. The obtained wood-polystyrene composites were found to have stronger static bending strength. (author)
The proton therapy gives an irradiation adapted to the shape and the depth of tumors ( eyes, head and neck) with a millimetric, even sub millimetric precision for the ophthalmological tumors. It is equally an excellent tool for the pediatrics tumors. For numerous treatments in France the proton therapy is associated to the photons treatments (x radiation). however, others physical treatments could modulate the medical offer, such thermal therapy or treatments by ultrasonic waves. (N.C.)
Dose-dependent behavior of the infrared stimulated luminescence (IRSL) decay from NaCl has been studied experimentally using only one aliquot irradiated with a range of 2-200 Gy {beta}-radiation doses. It was observed that the maximum IRSL intensity has not changed by an increase in dose though the total intensity increased as expected. Considering the possible implications of our findings for dosimeter, the results were compared with the other studies and discussed.
In this paper experimental observations and a theoretical analysis of periodic radiation bursts and macropulse formation in the start-up phase of a free-electron laser (FEL) oscillator are presented. This microwave FEL uses a long pulse electron beam with a slowly decaying voltage. The output radiation consists of a superposition of bell-shaped macropulses, each of which is composed of a periodic sequence of short micropulses. The micropulses are separated by a cavity round-trip time. Each bell-shaped macropulse has a random start-up time and amplitude. The startup of the radiation macropulses is correlated with random current spikes on the continuous electron beam. The observed macropulse signal agrees with a theoretical calculation of the impulse response of the FEL oscillator when the shift in the FEL resonance frequency arising from the slow voltage drop of the electron beam is ...
The effect of UV radiation in the wavelength region 230 nm to 302 nm on the ability of an irradiated mammalian cell to reactivate UV-irradiated mammalian virus was tested. An action spectrum for radiation enhanced reactivation (RER) is presented. The shape of the action spectrum points to a combined nucleic acid-protein target for UV radiation effects on this cellular parameter. An analysis of the results of others involving the biochemical and photobiological events involved in RER does not allow us to distinguish which macromolecule is the major contributor to this effect. Studies involving an analogous phenomenon in bacteris (Weigle reactivation) imply that RER and WR amy involve similar mechanisms. (author).
Argon ions irradiation of 12% Cr steels and Fe/Cr alloys results in the hardening up to 10000 MPa. This value exceeds the hardening level even for martensitic transformation. Along with the increase of microhardness following irradiation the shape of X-ray graph of the affected materials changes considerable. Hardening value and behavior are determined by temperature radiation doze, preliminary ageing, extent of cold strain and alloying. The odserved phenomenon is supposed to be caused by irradiation-induced structural transformations. Reversibility of radiation hardening of the materials in question was observed.
A computerised glow curve deconvolution (CGCD) analysis was applied to the main dosimetric peak of #alpha#-Al_2O_3:C in order to study the effects of light on the glow curve shape. It was shown that both the light-induced signal and the light-induced fading effects tend to shift the main dosimetric peak to higher temperatures and at the same time change its shape. Furthermore it was confirmed that the magnitude of the light-induced signal depends on radiation history and, by increasing the duration of light exposure, the magnitude of the light-induced signal reaches a plateau, thereby implying the saturation of the phototransfer process. (author).
With relation to the coals delivered as common samples in the coal fundamental technology development project, an experimental study was conducted on agglomeration characteristics and reaction characteristics in the fluidized-bed coal gasifier. For the experiment, used was a fluidized bed gasifier inserted with a cone-shape dispersion plate with a nozzle in the center. After raising the temperature of the gasifier up to 773K, gasification was conducted sending to the gasifier air from the nozzle and steam from the dispersion plate. The mean particle diameter and gas concentration of chars were measured till the temperature reaches 1373K. As a result of the experiment, it was confirmed that the carbon conversion ratio increases with a decrease in coalification degree of the coal. Moreover, influence of the coal kind was markedly observed at the grid zone of the lower part of the bed, and it was clarified that the lower carbon content ratio the ...
Generally the photonic band gap (PBG) is a multi-variable function of several parameters related to the shape and size of the dielectric columns of photonic crystals (PhCs), and a time-consuming step-by-step scanning process for each parameter has to be used to find their best combination yielding maximum PBG. In this letter, the widely used Nelder-Mead simplex algorithm is introduced to optimize these parameters simultaneously to find a larger PBG for a new kind of two-dimensional (2D) hexagonal GaAs-Air PhC. This structure can be conveniently produced by the single-exposure holographic lithography, and the specific holographic design is also systematically investigated. This study reveals that the band gaps of PhCs made by holographic lithography may be widened by introducing irregularity of the columns and lowering the symmetry of the structure.
Pd was deposited onto Si (111) 7x7 surface at approximately 700 K inside an ultrahigh vacuum transmission electron microscope. Plan-viewed transmission electron microscopy (TEM) observation indicated that the islands have two kinds of shapes, round and rectangular (one-dimensional) ones. In a diffraction pattern for the rectangular islands, extra spots along the <110> direction of the Si surface, spacing of which is 1/8 times as long as that of Si (220) spots, were seen. A high resolution TEM image showed the corresponding superstructure in the rectangular islands. In situ observation of the growing process of the rectangular islands showed repeat of introduction and relief of strains during the growth, suggesting that such superstructure would be constructed by stacking compositionally different phases or introducing defects so that the periodically maximized strain is relieved.
We propose a method of plasma production by capacity-coupled multidischarge (CCMD) at atmospheric pressure. The discharge gaps in the CCMD consist of a common electrode and a number of compact electrodes (CCE) which are directly coupled with small capacitors for quenching the discharge. A simple CCE structure is provided by a cylindrical capacitor, the inner conductor of which is used as a gap electrode. A short pulse discharge is observed to appear homogeneously at each CCE. A charge transfer for the single-pulsed discharge is 10-100 times as large as that of the conventional dielectric barrier discharge. A high efficiency of ozone production has been confirmed in the CCMD using O_2 gas. A device configuration of the CCMD is quite flexible with respect to its geometrical shape and size. The CCMD could be used to produce plasmas for various kinds of industrial applications at atmospheric pressure.
In this study, experiments were performed for pipe whip phenomena simulation. The analytical method was developed by combining several kinds of elements in ABAQUS computer code, standard version 5.2 . The transient analytical and the experimental results of the pipe whip test using 6 inch diameter pipe and U-shaped restraints are presented. It is shown that the adequate clearance decreases the restraint strains. As the overhang length increased, the maximum strain of restraints decreased. When the impact force increased, the maximum restraint strain increased slightly. The analytical models simulate the experimental impact phenomena very precisely, with slight conservatism. It is verified that the analytical method developed is very suitable to pipe whip phenomena analysis in nuclear power plants. 6 refs., 10 figs., 1 tab.
Some kind of one-dimensional (1D) peanut-shaped fullerene polymers (PSFPs) exhibit metallic properties, but their occurrence conditions are not yet clarified. By using the VASP (Vienna ab-initio simulation package) with density functional theory (DFT) and projector augmented wave (PAW) method, we have performed first-principles electronic structure calculations of four basic 1D PSFPs, T1, T2, T6, and T7 (the name of T1-T6 is the same as that of Wang et al. [9]) and two associated 1D PSFPs, T1SW1 and T6SW that are created by generalized Stone-Wales transformation (GSW) from T1 and T6. We found that almost regular six-membered rings connected throughout the tube are necessary to get metallic properties for the 1D PSFPs, although there may be several other conditions to expect metallic proper...
The spectrum, angular distribution, polarization and coherence properties of the radiation emitted by relativistic electrons undulating through a quasiperiodic tapered magnetic field are studied. Tapering the wavelength and/or field strength along the undulator's axis has the effect of spreading the spectral line to higher frequencies; interference over this broader spectral range results in a more complex line shape. The angular dependence, on the other hand, is not affected by the amount of taper. The polarization of the radiation in the forward direction is determined by the transverse polarization of the undulator, but the polarization changes off axis. The radiation patterns predicted here are distinct from those of untapered undulators, and their detection is now feasible. They will provide useful diagnostics of electron trajectories and threshold behavior in free-electron-laser ...
A mathematical model of multichannel radiometric inspection system was developed, in which the measurement results are reproduced in the form of a half-tone image equivalent to the radiation image of the irradiated object. The model makes the following assumptions: the beam of radiation is fan-shaped; the object of inspection is scanned discretely; the focal spot of the source is rectangular; the apertures of the detector are round, and the detectors themselves are equidistant from the sources, aimed at it, and form a close-packed array; the signals from the detectors are processed according to a time scheme; and the measurement results are corrected in a computer for normalizing the gains of the channels of the system. The mathematical model can serve as the basis for developing a method of calculating the optimal parameters of a multichannel radiometric system with visualization of the radiation ...
A Pulsed Radiation Dosimetry System designed to measure radiation produced by particle accelerators is described. The problems associated with total-dose measurement of irregular shaped pulses of ionizing radiation have been simplified. The system responds to extremely narrow pulses of charged particles or X-rays using a pin diode as the detector. Direct readout of dose in rads (Si) is displayed on a 3-1/2 digit digital panel meter. The system will operate in either the multiple-pulse or single-pulse mode. The multiple-pulse mode would be useful in monitoring or tuning a linear accelerator. In the single-pulse mode the system will automatically display total dose of a transient event in real time and hold that measurement indefinitely or until the next measurement is made. The system features an automatic reset in either mode.
In VHTGR (Very High Temperature Gas-cooled Reactor), the radiation plays an important role in heat transfer through the cavity in RCCS (Reactor Cavity Cooling System). We performed the series of experiments to measure the emissivity using the infrared thermometer with wavelength range of 8#approx#14 #mu#m. As the first step, the transmittance of Zinc Selenide (ZnSe) window was measured to estimate the emissivity that can compensate the attenuation effect of window. The kind of gas with various concentrations in the cavity will be released during postulated accidents to the coolant type, so it is essential to estimate the effects of gas on the measurement of emissivity. In this manner we measured the emissivity with the air, the helium and the steam inside chamber. The results represent that the concentration of the air and the helium do not affect the emissivity significantly while the steam decreases the measured emissivity relatively. It ...
Nuclear Hartree-Fock (HF) + BCS calculations have led to predictions of shape isomerism in isotopes of Pt, Hg and Os nuclei. These have been confirmed through the observation of superdeformed rotational bands in {sup 190,{hor ellipsis},194}Hg. Encouraged by these measurements and similar observations in {sup 194}Pb, we have extended these calculations to a wide range of contiguous nuclei. These HF results, for {sup 192,194}Pt, {sup 190,{hor ellipsis},198}Hg and {sup 194}Pb, have been employed in a Generator Coordinate Method (GCM) calculation utilizing the quadrupole deformation as the generating variable. The resulting spectra confirm the conclusions drawn from the HF results and agree with those experiments which have been performed. Adding a phenomenological assumption for the moments of inertia of our GCM states, we can construct the radiative transitions within and out of the superdeformed band. The results are in good agreement with the ...
Epidemiological studies will not solve the shape of the dose effect curve for stochastic effects in the low dose range. Unicellular processes are necessary for the primary processes so that no threshold dose exists. This is evident for somatic and genetic mutations. Not clearly solved is this question for the complex carcinogenesis. These processes develop with manifold interacting molecular and cellular steps. (orig.).
A new kind of receiver-reactor for high-temperature solar furnaces is proposed. The main body of the receiver component is an ellipsoid of revolution with specularly reflecting inner walls. The reactor component, a crucible, is placed at one focal point and the aperture at the other. With this arrangement, substantially all of the incident radiation from the concentrator should reach the reactor directly or after one reflection from the cavity walls. An analysis of the radiative exchange among the surfaces is presented. The analysis provides a tool for a parametric study and optimization of the design. It is found that, in contrast to that of conventional well-insulated cavity receivers, its collection efficiency is not very sensitive to the size of its aperture.
Handheld, backpack, and mobile sensors are elements of the Global Nuclear Detection System for the interdiction and control of illicit radiological and nuclear materials. They are used by the U.S. Department of Homeland Security (DHS) and other government agencies and organizations in various roles for border protection, law enforcement, and nonproliferation monitoring. In order to systematically document the operational performance of the common commercial off-the-shelf portable radiation detection systems, the DHS Domestic Nuclear Detection Office conducted a test and evaluation campaign conducted at the Nevada Test Site from January 18 to February 27, 2006. Named 'Anole', it was the first test of its kind in terms of technical design and test complexities. The Anole test results offer users information for selecting appropriate mission-specific portable radiation detection systems. The campaign also ...
Radiation-and-thermal-combined degradation of some kinds of cable insulating and jacketing materials was evaluated by accelerated aging tests. Plasticized polyvinyl chloride (PVC), silicone rubber, crosslinked and non-crosslinked halogen-free flame-retardant polyolefins (NH-XLPO and NH-PO) and ethylene-propylene rubber (EP rubber) of experimental formulation were degraded at accelerated rates, that are 50-1000 times the degradation rate under standard conditions (e.g.; 1Gy/h, 50degC), and a method to assess the lifetime of these materials under standard conditions was studied. The degradation was investigated by measuring tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for these materials were in proportion to the increase in accelerated rate. The PVC lifetime estimated from sequential aging tests had a tendency to extend beyond that from simultaneous aging tests, while the lifetime of other ...
As the ground state potential curve is strongly related to spectral line shapes, the minumum position of the ground state potential is obtained from the experiemental absorption profile k({delta}{nu}, T) at high density of the radiating atoms. The temperature dependence of the absorption processes of Hg and Cd lines 253.65 and 326.1 nm, respectively perturbed by inert gases (Xe, Kr, Ar and Ne) had been carefully studied over a wide spectral range. Using the point of the maximum temperature dependence {delta}{nu} {sub m} in each case, we are able to calculate the position of the ground state potential R {sub m} using a simple formula.
Background: the authors report on the conception and first clinical application of a donut-shaped high-dose configuration for proton therapy (PT). This approach allows one to intensify target volume dose coverage for targets encompassing a critical, dose-limiting structure - like here, the cauda equina -, whilst delivering minimal dose to other healthy structures surrounding the target, thereby reducing the integral dose. Methods and results: intensity-modulated PT methods (IMPT) for spot scanning were applied to create and deliver a donut-shaped high-dose configuration with protons, allowing treating > 75% of the target with at least 95% of the prescribed dose of 72.8 CGE, whilst restricting dose to the cauda equina to 60-65 CGE. Integral dose was lower by a factor of 3.3 as compared to intensity-modulated radiotherapy with photons (IMXT). Conclusion: IMPT and spot scanning technology allow a potentially clinically useful approach which ...
Background: the authors report on the conception and first clinical application of a donut-shaped high-dose configuration for proton therapy (PT). This approach allows one to intensify target volume dose coverage for targets encompassing a critical, dose-limiting structure - like here, the cauda equina -, whilst delivering minimal dose to other healthy structures surrounding the target, thereby reducing the integral dose. Methods and results: intensity-modulated PT methods (IMPT) for spot scanning were applied to create and deliver a donut-shaped high-dose configuration with protons, allowing treating > 75% of the target with at least 95% of the prescribed dose of 72.8 CGE, whilst restricting dose to the cauda equina to 60-65 CGE. Integral dose was lower by a factor of 3.3 as compared to intensity-modulated radiotherapy with photons (IMXT). Conclusion: IMPT and spot scanning technology allow a potentially clinically useful approach which is ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
A 'Laboratory of Quantitative Methods in Monument Research' is being built at the CTU Prague. Its primary orientation is the investigation of historic architecture, although other objects of art can also be investigated. In the first phase, two radiation methods are being established, but it is set up in such a way, that various other methods can readily be added in its future development. The radiation methods chosen for the initial development of the laboratory are: thermoluminescence dating and X-ray fluorescence analysis. The design of the automated TL-reader, built in our laboratories, is adjusted for the purpose of dating of historic brick architecture (which, of course, does not exclude applications for ceramics and other materials). The investigation of renaissance architecture in southern Bohemia and Moravia is under preparation as the first large campaign of this kind in the Czech Republic. ...
A 'Laboratory of Quantitative Methods in Monument Research' is being built at the CTU Prague. Its primary orientation is the investigation of historic architecture, although other objects of art can also be investigated. In the first phase, two radiation methods are being established, but it is set up in such a way, that various other methods can readily be added in its future development. The radiation methods chosen for the initial development of the laboratory are: thermoluminescence dating and X-ray fluorescence analysis. The design of the automated TL-reader, built in our laboratories, is adjusted for the purpose of dating of historic brick architecture (which, of course, does not exclude applications for ceramics and other materials). The investigation of renaissance architecture in southern Bohemia and Moravia is under preparation as the first large campaign of this kind in the Czech Republic. Radionuclide X-ray ...
In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through a plastic optical fiber to a remote light-measuring device such as a PMT or a photodiode. The Cherenkov light could be also produced in the plastic optical fiber itself and be detected by a light-measuring device. Therefore, it could cause problems or limit the accuracy of the detection of a fluorescent light signal that is proportional to dose. The objectives of this study are to measure, characterize and eliminate Cherenkov light generated in a plastic optical fiber used as a component of a fiber-optic ...
This paper explains technologies for turbo chargers used in light cars. Light car engine turbo chargers have been given various improvements responding to needs of the market. Since ball bearings have less mechanical loss than sliding bearings, and enhances greatly the turbo efficiency, they are used in some high performance engines of light cars. While the conventional ball bearing has used high hardness bearing steel, the new standard cars started using ceramic ball. The currently used light car gasoline engines are divided into two kinds, serial three-cylinder type and serial four-cylinder type, either having merits and demerits. The new twin entry turbo developed by IHI arranges divided exhaust gas ports above and below to simplify the manifold shape, and realizes smooth flow by twisting the exhaust gas flow path inside the turbine housing. This makes the dynamic pressure of the exhaust gas more effectively utilized, enhancing the boost ...
Homogeneous mixtures of Ce0.8Gd0.2O1.9 (GDC) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) nanopowders were successfully synthesized using induction plasma by axial injection of a solution. The resulting nanocomposite powders consisted of two kinds of nanopowders with different mass ratio of GDC/LSCF, such as 3/7 and 6/4. The morphological features, crystallinity, and the phases of the synthesized powders were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), local energy-dispersive x-ray spectroscopy (EDS) analysis, and x-ray diffraction (XRD). The nanopowders are almost globular in shape with a diameter smaller than 100?nm and their BET specific areas are around 20?m2?g?1. The GDC and LSCF phases are well distributed in the nanopowders. In addition, suspens...
Pd was deposited onto Si (111) 7x7 surface at approximately 700 K inside an ultrahigh vacuum transmission electron microscope. Plan-viewed transmission electron microscopy (TEM) observation indicated that the islands have two kinds of shapes, round and rectangular (one-dimensional) ones. In a diffraction pattern for the rectangular islands, extra spots along the <110> direction of the Si surface, spacing of which is 1/8 times as long as that of Si (220) spots, were seen. A high resolution TEM image showed the corresponding superstructure in the rectangular islands. In situ observation of the growing process of the rectangular islands showed repeat of introduction and relief of strains during the growth, suggesting that such superstructure would be constructed by stacking compositionally different phases or introducing defects so that the periodically maximized strain is relieved.
Radiation induced polymerization of methylmethacrylate and copolymerization of styrene-acrylonitrile mixture in mamrase Carpinus betulus was carried out by means of #gamma#-ray, under different moisture levels and additives. Under all conditions the degree of polymerization was as high as 60%. No pronounced differences were observed in the kinetics of the polymerization of MMA either with moisture content of wood nor with kind and amount of additives. At high moisture (80% RH) content the dimensional stability of wood-PMMA was increased four fold as compared with untreated wood. The hardness increased about 100% for a weight conversion of monomer of about 30 to 40%. Hardness of this wood-polymer composite is comparable to that of the best noble woods in the world. (author).
In the Peruvian natural forest there are several kind of woods, some of those are not of commercial interest, because have not resistance at termites and wet, are too soft, or can not be well finished, in the others. The present work is devoted to improvement of the physical properties of wood, such as hardness, traction, wet resistance, etc., by means of the generation of a composite wood-polymers cured by using gamma irradiation. The main objective is to establish the main parameters for the polymerization process (economic technical aspect) that decrease the amount of water absorption, in consequence the volumetric variation of Catahua, Mohena and Capirona woods. Gamma irradiation also provides good protection against the biological agents. In consequence, these woods increase its intrinsic and economic values. (author)
A new furnace for neutron diffraction experiments is capable of heating and cooling a sample very rapidly. The rapid heating is done by two circular infrared lamps placed over and under a sample, whose radiation is roughly focused on the sample by a reflector. The rapid cooling is done by high-pressure gas blows against the sample from two circular nozzles which are also placed over and under the sample. This system enables us to obtain the heating rate of over 1000"0C/min and cooling rate of -500"0C/min for an alloy of 10 mm diameter and 30 mm length. The performance is sufficient to carry out some kinetics measurements in real-time neutron diffraction by the use of a position-sensitive detector. This kind of experiment is demonstrated by the observation of the relaxation process of order--disorder transitions in CuZn and Ni_3Mn alloys.
Some results on mechanical property study of copper and titanium subjected to impact load and next to neutron irradiation are presented. It was shown that shock wave influence involves a substantial shape change of the stress-strain diagram and of respective mechanical characteristics. Yield- and ultimate strength were substantially increased, as well as hardness with a considerable drop of plasticity. Also a heat stability of copper and titanium specimens was studied after being treated with shock-waves and neutron radiation. Results are given of electron microscope study of titanium structure sfter explosion hardening, which caused decomposition of hydride segregations in titanium and increased dislocation density.
Electron beam therapy has often been used for radiation therapy of carcinomas of the buccal mucosa, though side effects, including stomatitis and dermatitis, are known to exist. We experimented using the additional back scatter and transit with the phantom under a lead plate within the irradiation field, in order to better focus the dose on the target volume moreover, we fabricated a mouthpiece fitted with a lead plate shaped to the target volume, and with respect to the influence of the mouthpiece on stomatitis and dermatitis, obtained good clinical results. (author).
Electron beam therapy has often been used for radiation therapy of carcinomas of the buccal mucosa, though side effects, including stomatitis and dermatitis, are known to exist. We experimented using the additional back scatter and transit with the phantom under a lead plate within the irradiation field, in order to better focus the dose on the target volume moreover, we fabricated a mouthpiece fitted with a lead plate shaped to the target volume, and with respect to the influence of the mouthpiece on stomatitis and dermatitis, obtained good clinical results. (author).
The phenomenon of radiation blistering by helium ion bombardment has been the subject of extensive studies in recent years because of its technological importance in thermonuclear fusion devices and reactors. However, the mechanism of radiation blistering is still not well understood. There are two different models of blister formation: the gas-pressure model and the lateral stress model. The former model is, however, supported by many experimental observations, the prominent one is that of Evans and Eyre who observed blisters appearing on the front and rear surfaces of a thin wedge-shaped molybdenum foil irradiated by helium ions. Their experiment also indicates that the thickness of the irradiated specimen could be important in affecting the characteristics of blisters. With this in view, we have studied the development of blisters in thin foils of tantalum by 30 MeV ..cap alpha..-particle bombardment.
The phenomenon of radiation blistering by helium ion bombardment has been the subject of extensive studies in recent years because of its technological importance in thermonuclear fusion devices and reactors. However, the mechanism of radiation blistering is still not well understood. There are two different models of blister formation: the gas-pressure model and the lateral stress model. The former model is, however, supported by many experimental observations, the prominent one is that of Evans and Eyre who observed blisters appearing on the front and rear surfaces of a thin wedge-shaped molybdenum foil irradiated by helium ions. Their experiment also indicates that the thickness of the irradiated specimen could be important in affecting the characteristics of blisters. With this in view, we have studied the development of blisters in thin foils of tantalum by 30 MeV #alpha#-particle bombardment. (orig.).
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 Pinnacle3 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 w...
Thermoluminescence (TL) properties of sphene and epidote are of interest in studies related to their radiation damage. Natural and artificially induced TL of these minerals has, therefore, been investigated. Both minerals exhibit complex glow curves with several overlapping peaks. The Tsub(m) -Tsub(STOP) thermal cleaning procedure has revealed three peaks in the ..gamma.. ray induced glow curve of each mineral. That these peaks obey second order kinetics was indicated by the continuously slanting structure of the Tsub(m)-Tsub(STOP) curve. The TL parameters E and s have been calculated using (i) the initial rise method, and (ii) the glow-peak shape method. In general, the values of E calculated by the first method are found to be higher than those from the second. The TL curve-fitting method is also applied in order to calculate these parameters and to serve as a cross-check on the results.
Radiation sterilization has several merits that it is a positively effective sterilization method, it can be used to sterilize low heat-resistant containers and high gas barrier films, and there is no possibility of residual chemicals being left in the packages. It has been commercially used in 'Bag in a Box' and some food containers. The #gamma# ray and an electron beam are commonly used in radiation sterilization. The #gamma# ray can sterilize large size containers and containers with complex shapes or sealed containers due to its strong transmission capability. However, since the equipment tends to be large and expensive, it is generally used in off production lines. On the other hand, it is possible to install and electron beam system on food production lines since the food can be processed in a short time due to its high beam coefficient and its ease of maintenance, even though an electron beam has limited usage such ...
Eddy current testing (ECT) method is widely used as the non-destructive evaluation (NDE) of the various kinds of material degradation occurring in nuclear power plants (NPPs) components including steam generator (SG) tubes. Detection of any defects or flaws in the steam generator tubes in the early stage is very important in maintenance of NPP for its primary role as the pressure boundary with thin wall thickness. Although the ECT technique provides lots of information for a SG management, it has a generic problem in its reliability due to a low ability in detect of small defects and some difficulty in a signal analysis. For the improvement of these shortcomings in conventional ECT, profile-MRPC (motorized rotating pancake coil) ECT technology was developed in KAERI. The key of this new technology is the development of new eddy current probes, designated as a diagnostic probe (D-probe). The D-probe is furnished with a simultaneous dual function of a defect ...
Eddy current testing (ECT) method is widely used as the non-destructive evaluation (NDE) of the various kinds of material degradation occurring in nuclear power plants (NPPs) components including steam generator (SG) tubes. Detection of any defects or flaws in the steam generator tubes in the early stage is very important in maintenance of NPP for its primary role as the pressure boundary with thin wall thickness. Although the ECT technique provides lots of information for a SG management, it has a generic problem in its reliability due to a low ability in detect of small defects and some difficulty in a signal analysis. For the improvement of these shortcomings in conventional ECT, profile-MRPC (motorized rotating pancake coil) ECT technology was developed in KAERI. The key of this new technology is the development of new eddy current probes, designated as a diagnostic probe (D-probe). The D-probe is furnished with a simultaneous dual function of a defect ...
Full text.S235JR carbon steel is one of the most popular steels used in Lebanon. It is imported by steel dealers and is widely used by all fabricators and manufacturers of steels for many structural purposes and applications. This kind of steel has good ductile properties as well as excellent weldability. It is still known by its previous designation St 37-2 or E 24-2. S235JR is produced in many shapes and thicknesses such as steel plates, sheets, angles and different other geometric shapes. Standard chemical and mechanical tests were conducted and reported on S235JR hot-rolled structural low-carbon mild steel specimens collected from Lebanese steel market. The main objective of this work is to assure the compliance of these properties with those set by the steel manufacturer. The above mentioned tests were performed at the laboratories of the Industrial Research Institute (IR) in Lebanon to assure the quality and ...
Radio, optical and X-rays telescopes are improving our knowledge of deep space. All these telescopes detect electromagnetic radiation at various frequencies. But a different kind of radiation is generated in the deeper space; it is the gravitational one. Gravitational waves change the space-time metric. As a consequence, GW telescopes should detect an extremely small strain (h < 10/sup -21/) of the geometry of a reference frame; if the frame has a reference dimension (L) of some kilometers, the deformation amplitude ( Delta L = h * L) is limited to 10/sup -16/ meters. Laser interferometers are the most suitable devices to make precise measurements of distances. Their resolution is limited by the laser wavelength ( lambda = 10/sup -6/ meters) and by the light wave-shift detection capability ( Delta Phi = 1 ppb). These theoretical limits are strongly degraded by different noise sources, which reduce the actual resolution ...
BackgroundMany molecules of interest are flexible and undergo significant shape deformation as part of their function, but most existing methods of molecular shape comparison (MSC)...Full Text Available
For the purpose of risk estimates from radiation carcinogenesis including leukemogenesis and radiation genetic effects, the biological significant dose is not the tissue kerma in air but the absorbed dose in organ or tissue with respect to carcinogenic and leukemogenic effects or genetic effects. In order to estimate organ or tissue dose from the tissue kerma in air, a ratio of the organ or tissue dose to the tissue kerma in air for survivors in Hiroshima and Nagasaki was calculated with the aid of the Snyder's mathematical phantoms constructed so as to simulate the body shape of survivors aged 5, 10 years old and adult at the time of atomic bomb detonations. The ratios were corrected for the angular distribution of atomic bomb radiations, assuming an anisotropic angular distribution for the survivors exposed to the atomic bombs in open air and the isotropic distribution for the survivors incide a ...
... and testing of unidirectional composites, there are serious doubts about the possibility of obtaining a true ultimate compressive strength for this kind ...
In the use of doxorubicin and radiation for treatment of human malignant tumors in vivo, the relationship between treatment-induced apoptosis and Ki-67 labeling index was investigated. Four human tumor xenografts (ependymoblastoma, NNE; primitive neuroectodermal tumor, YKP; small cell lung carcinoma, GLS; glioblastoma, KYG) were transplanted under the skin of thigh of the nude mice (BALB/cA JcL-nu). The mice were given a single radiation dose of 1 Gy, or doxorubicin alone intraperitoneally at a dose of 8 mg/kg. After treatment, sections of tumor specimens were prepared from paraffin-embedded tissues. Hematoxylin and eosin staining, TUNEL staining, and immunohistochemical analysis of Ki-67 were performed. In NNE, apoptotic cells appeared most frequently after treatment compared with all other tumors, and the incidence of apoptosis in the radiation-treated group was much higher than in the doxorubicintreated group. As the ...
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 ...
The development of leukemia and thyroid cancer is characterized by activation of the abl oncogene and ret oncogene, respectively. In order to clarify the relationship between these gene aberrations and radiation, the pro-myelogenous leukemia-derived cell line HL60 and the thyroid cancer-derived cell line 8505C, were irradiated in vitro with 100Gy of X-rays. RNA was then extracted from 10"8 cells of the respective cell lines and examined by the reverse transcription PCR method for rearrangements of abl and ret genes. Five kinds of positive bands were observed in the HL-60 cells irradiated with 100Gy of X-ray. Similarly, six positive bands were also observed in the 8505C cells irradiated with 100Gy. In vitro X-irradiation activation of oncogenes found in radiation induced cancers imply that gene rearrangement by X-rays is involved in the development of malignant tumors. Furthermore, in an experiment to detect ...
The absorption of solar heat and the attendant thermal and mechanical loadings on the tubes of cavity receivers depend predominantly on the flux distribution of the incident solar radiation. For an axially symmetric cavity receiver with a parabolic dish collector, it is simple to determine the insolation pattern on the receiver internal surfaces if the system is ideal. In such a system the surface of the dish is perfectly parabolic (no contour flaws are present), and the sun's central ray impinges on the dish surface parallel to the focal axis (no sun tracking flaws are present). These two conditions cannot be achieved in practice, and therefore the feasible parabolic dish system is referred to as a real system although, in actual fact, it is only an approximation to any actual system. The purpose of this paper is to devise calculation principles which permit analysis of a receiver designed for ideal conditions to verify its structural adequacy under the ...
Intensive work has long been going on to find out the unknown origin that sets off curious tribo-physicochemical phenomena and that causes various kinds of problems in oil-lubricated sliding contacts in mechanical and processing systems. The strange tribochemical reaction is one of the such curious chemical phenomena observed in the degradation of perfluoropolyether (PFPE) lubricating oil film in a hard disk drive. Plasma (triboplasma) (Nakayama and Mirza 2006 Tribol. Trans. 49 17) would be one of the most probable origins of the problems if it were generated sufficiently intensely in oil-lubricated sliding contacts, as it is in such a highly energetic state. The generation of plasma was predicted in both dry and oil-lubricated sliding (Nakayama 1997 Japan. J. Tribol. 42 1077, Nakayama 2004 Surf. Coat. Technol. 188-189 599). However, plasma generation in industrially important oil-lubricated contacts has not yet been proven, though it has been found in dry sliding ...
We have measured K-edge X-ray absorption spectra of argon in sputtered aluminum films at a synchrotron radiation facility (the Photon Factory). We found that the energy and shape of white line change when the film is annealed at 500 C and the spectrum becomes resembling that of argon implanted in silicon. From the analyses of the X-ray absorption spectra and TEM observation we concluded that argon exists as very small atom clusters with a diameter less than 1 nm or exist as isolated atoms in the as-sputtered aluminum film, and that the size of the clusters become as big as 10 nm diameter when the film is heated. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
A theoretical study of an exciton confined in a quantum ring is presented. The quantum ring is described as a two-dimensional circular quantum dot with a repulsive core, which is modelled with the help of two Gaussian functions. We have applied the variational method and investigated the evolution of the low-energy exciton spectrum with the change of the confinement potential. The calculations have been performed for the recently produced self-assembled ring-shaped InGaAs quantum dots. We have shown that the repulsive core strongly increases the radiative transition probability from the exciton ground state at the expense of the decreasing probability of the transitions from the excited states. This effect results from the orthogonality properties of the exciton wavefunctions, which are specific to the quantum-ring confinement potential. We have studied the characteristic features of the exciton spectrum, which can be used as a signature of the ...
Energy flows in deep inelastic electron-proton scattering are investigated at a centre-of-mass energy of 296 GeV for the range Q{sup 2}{>=}10 GeV{sup 2} using the ZEUS detector. A comparison is made between events with and without a large rapidity gap between the hadronic system and the proton direction. The energy flows, corrected for detector acceptance and resolution, are shown for these two classes of events in both the HERA laboratory frame and the Breit frame. From the differences in the shapes of these energy flows we conclude that QCD radiation is suppressed in the large-rapidity-gap events compared to the events without a large rapidity gap. (orig.)
A programme has been initiated by the Coordinating Office for Monitoring of enhanced natural radioactivity of the Federal Office for Radiation Protection to investigate different kinds of sample materials with enhanced naturally occurring radioactivity (NORM) such as scales from oilfield and naturally gasfield pipes, blast furnace sludge and sinter dust from the production of pig iron, as well as bauxit and red mud from the production of aluminium oxide. The aim of these investigations is to find proper preparation and measuring methods which allow, in particular, a sample treatment with optimised effort combined with a reliable determination of the specific activities of the dominating radionuclides. Of particular interest is the method of gamma-ray spectrometry, since this method has been used for most of our studies of sample materials. Due to different compositions of calibration and NORM-samples, e.g. different densities, and the analysis ...
Activation has been used for many kinds of useful applications, such as use of the radioisotopes for diagnosis and treatment of cancer, and wear (or corrosion) investigation for using thin layer activation (TLA) technique, etc. But activation also has severe problems for the post-processing of the samples; such as time-loss, inconvenience of sample handling, personal radiation safety, etc. For in-vitro experiments, we observed death of tumor cells by proton irradiation. The use of large activated container material can cause erroneous results in this case. To solve these problems, we studied why the samples were activated and how the level of the activation could be reduced. In proton beam irradiation experiments, the target materials could be defined as the container and sample itself. We could easily reduce activation of container material comparing to activation of sample itself. Therefore, we tried to find less activated container material ...
Dose calculations for radiation arc therapy are traditionally performed by approximating continuous delivery arcs with multiple static beams. For 3D conformal arc treatments, the shape and weight variation per degree is usually small enough to allow arcs to be approximated by static beams separated by 5"0-10"0. But with intensity-modulated arc therapy (IMAT), the variation in shape and dose per degree can be large enough to require a finer angular spacing. With the increase in the number of beams, a deterministic dose calculation method, such as collapsed-cone convolution/superposition, will require proportionally longer computational times, which may not be practical clinically. We propose to use a homegrown Monte Carlo kernel-superposition technique (MCKS) to compute doses for rotational delivery. The IMAT plans were generated with 36 static beams, which were subsequently interpolated into finer angular intervals for dose ...
A relationship between partial derivatives of the associated Legendre function of the first kind with respect to its degree, Formula Not Shown , and to its order, Formula Not Shown , is established for Formula Not Shown . This relationship is used to deduce four new closed-form representations of Formula Not Shown from those found recently for Formula Not Shown by the author [R. Szmytkowski, On the derivative of the associated Legendre function of the first kind of integer degree with respect to its order (with applications to the construction of the associated Legendre function of the second kind of integer degree and order), J. Math. Chem. 46 (2009) 231]. Several new expressions for the associated Legendre function of the second kind of integer degree and order, Formula Not Shown , suita...
The proton beam has an advantage of the sharp dose falloff in dose distribution called Bragg peak while conventional radiation therapy modalities such as photons exhibit considerable amount of exit dose. To take advantage of this property it is important to know the exact location of the distal dose falloff. An error can cause overdose to the normal tissue or underdose to the tumor volume. The only way of finding out the dose distribution in-situ in particle therapy is to measure the gammas produced by nuclear reactions with tissue materials. Two kinds of gammas can be used: one is prompt gamma and the other is coincident gamma from the positron-emission isotopes. We chose to detect prompt gammas, and developed a prompt gamma scanning system (PGS). The proton beams of the proton therapy facility at National Cancer Center were used. The gamma distribution was compared to the dose distribution measured by an ionization chamber at three different ...
Seven types of shellfish were irradiated by gamma ray at doses of 0, 3 and 6 kGy. Pulse photo-stimulated luminescence (PPSL) and thermoluminescence (TL) methods were employed to detect the radiation treatment. The screening of irradiation was carried out by the PPSL method followed by identification using the TL technique. Most of the irradiated shellfish were screened out correctly and only a few showed photon counts a bit higher than the lower threshold value by much lower than the upper threshold value. The TL method was employed using minerals isolated from all the control and irradiated shellfish samples by density gradient treatment. Three parameters, integrated intensities of first glow curves (TL1), ratios of first to that of second glow curves (TL1/TL2), and the shapes of maxima of first glow curves, were utilized for the identification of gamma ray treatment of shellfish. (author)
Radiation defects produced by helium implantation were used to shape profiles of palladium (Pd) and platinum (Pt) atoms in-diffusing (for 20 min at temperatures 600-800 deg. C) either from surface silicide (Pd_2Si, PtSi) or implanted layers. Results show that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centers - the acceptor level of substitutional Pd (E _c - 0.22 eV) or Pt (E _c - 0.23 eV). While optimum conditions for Pt in-diffusion are about 700 deg. C, Pd gives the best results already at lower temperatures (600 deg. C) where it also exhibits higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by Pd and Pt, exhibited similar trade-off between the static and ...
E-35 reported the specific air flow analysis program using a CFSV model (including a human body model) to develop a high-accuracy evaluation simulator for heterogeneous thermal environment based on human thermal physiological conditions. E-36 reported development of the radiation heat transfer analysis module by using a numerical integral method to calculate shape factors. Radiation heat transfer characteristics every body part were clarified quantitatively by this module. E-37 reported the results on continuous measurement of physiological conditions and thermal environment factors every monitor under controlled indoor thermal environment, to collect measurement data necessary for improving the accuracy of a prediction program for human body temperatures. E-38 reported the study result on physiological reaction and subjective evaluation through an examinee experiment in a blood controlled region, to collect basic data for ...
Accurate dose calculation in radiation treatment planning is most important for successful treatment. Since human body is composed of various materials and not an ideal shape, it is not easy to calculate the accurate effective dose in the patients. Many methods have been proposed to solve inhomogeneity and surface contour problems. Monte Carlo simulations are regarded as the most accurate method, but it is not appropriate for routine planning because it takes so much time. Pencil beam kernel based convolution/superposition methods were also proposed to correct those effects. Nowadays, many commercial treatment planning systems have adopted this algorithm as a dose calculation engine. The purpose of this study is to verify the accuracy of the dose calculated from pencil beam kernel based treatment planning system comparing to Monte Carlo simulations and measurements especially in inhomogeneous region. Home-made inhomogeneous phantom, Helax-TMS ...
A new emissivity measurement device with inductive sample heating is described. The disc shaped samples can be measured between 800 C and 2000 C in vacuum or in each available gas atmosphere. Two kinds of surface temperature measurement methods are described, one by measuring in a blackbody hole and one by measuring at the surface without additional measures to correct emissivity. Total normal and spectral emissivity at wavelengths between 0,5 {mu}m and 8,3 {mu}m of various high temperature materials like platinum and Pt-Rh-alloys, siliconcarbide and molybdenum disilicide have been measured. From the investigated materials a few have been selected as reference samples for comparative emissivity measurements fullfilling the requirement of stability on air up to 400 C to 1000 C in order to ensure reproducibility of the results at different measurement conditions in air and in vacuum. (orig.) [Deutsch] Der Aufbau einer neuen Messapparatur fuer ...
The high-purity-oxygen activated sludge process will be used to expand secondary treatment capacity and improve water quality in Santa Monica Bay. The facility is operated by the city of Los Angeles Department of Public Works` Bureau of Sanitation. The overall Hyperion Full Secondary Project is 30% complete, including a new headworks, a new primary clarifier battery, an electrical switch yard, and additional support facilities. The upgrading of secondary facilities is 50% complete, and construction of the digester facilities, the waste-activated sludge thickening facility, and the second phase of the three-phase modification to existing primary clarifier batteries has just begun. The expansion program will provide a maximum monthly design capacity of 19,723 L/s(450 mgd). Hyperion`s expansion program uses industrial treatment techniques rarely attempted in a municipal facility, particularly on such a large scale, including: a user-friendly intermediate pumping station featuring 3.8-m ...
Benchmark calculations for SCALE4.4 CSAS6 module have been performed for 31 UO{sub 2} fuel, 15MOX fuel and 10 metal material criticality experiments and then calculation biases of the SCALE 4.4 CSAS6 module have been revealed to be 0.00982, 0.00579 and 0.02347, respectively. When CSAS6 is applied to the criticality safety analysis for the mockup facility in which several kinds of nuclear material components are included, the calculation bias of CSAS6 is conservatively taken to be 0.02347. With the aid of this benchmarked code system, criticality safety analyses for the mockup facility at normal and hypothetical accidental conditions have been carried out. It appears that the maximum K{sub eff} is 0.28356 well below than the critical limit, K{sub eff}=0.95 at normal condition. In a hypothetical accidental condition, the maximum K{sub eff} is found to be 0.73527 much lower than the subcritical limit. For another hypothetical accidental condition the nuclear material ...
In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but overcoming some of these experimental ...
In vivo, mammalian lenses have the capacity to effect fully reversible changes in shape, and possibly volume, during the accommodation process. Isolated lenses also change shape...Full Text Available
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 ...
The proposed aim of the work is to verify the effects produced on different kinds of environmental pollutants after exposure to a low frequency radiation such as microwaves. They have proved capable of producing minimum heating of the matrix as well as modifications in the structure of the molecules at the level of simple bonds. Steps were also taken ti check whether the degradation action of the microwaves could be boosted by sunlight. For this reason tests were run also on samples irradiated using microwaves and a lamp capable of simulating the sun's spectrum, as well as in the presence of a single lamp. [Italian] Lo scopo di questa ricerca e' di verificare gli effetti prodotti su inquinanti ambientali, di diversa natura, a seguito di un'esposizione ad una radiazione a bassa frequenza come le microonde. Le microonde possono produrre minimi riscladamenti della matrice e modificazioni della struttura delle molecole, a ...
This present study evaluated the effect of gamma radiation on the fungal survival in packed medicinal plants, purchased from wholesale and retail market, in different period (0 and 30 days) after the treatment. Five kind of medicinal plants (Peumus boldus, Camellia sinensis, Maytenus ilicifolia, Paullinia cupana and Cassia angustifolia), were collected from different cities of Sao Paulo State, and submitted to irradiation treatment using a 60Co source (type Gammacell 220) with doses of 5,0 kGy and 10 kGy and at dose rate of 3.0 kGy/h. Non-irradiated samples (control group) were used for fungal counts and serial dilutions from 10-1 to 10-6 of the samples were seeded in duplicates and plated using the surface culture method in Dichloran 18% Glycerol Agar (DG 18) and were counted after five days at 25 deg C. The control group revealed the presence of genera Aspergillus and Penicillium, which are known as toxigenic fungi and a few samples of ...
A 450 MeV Synchrotron Radiation Source, Indus-1 is being constructed at Centre for Advanced Technology at Indore in central India. This paper narrates our experience in construction and alignment of synchrotron machines which was first of its kind for most of us. Careful design, planning and execution of the work yielded modest results so that alignment accuracies between 0.1 to 0.3 mm could be achieved (in booster synchrotron) and, which have proved to be adequate up till now. The building of the SRS complex was constructed such that machine rings have their foundations isolated from rest of the building. A number of 100 x 150 mm size steel plates were embedded in the concrete of floor and walls to serve as base for reference surveying marks which were established later. The pre-injector and booster ring are enclosed in a radiation shielding zone with separate ventilation system. Dipoles, quadrupoles and a few sextupoles ...
The subject of quantum optics has undergone considerable development in the last twenty-five years. Spurred by the invention of the laser, the theoretical understanding of the coherence and statistical properties of optical beams has now attained a stage of maturity where it is possible to treat different kinds of light sources. Over approximately the latter half of this period of development in quantum optics, the free-electron laser (FEL) has been developed to the point where it is now regarded as a tunable light source of considerable versatility, with prospects of producing radiation over a wide range of wavelengths at large levels of power. Since the basic mechanism for radiation gain in an FEL can be understood in classical terms, much of the literature on the subject does not need to venture outside the domain of classical physics. However, it is natural that the coherence and statistical properties of photon beams ...
Shaping has proven to be a powerful but precarious means of improving reinforcement learning performance. Ng, Harada, and Russell (1999) proposed the potential-based shaping algorithm for adding shaping rewards in a way that guarantees the learner will learn optimal behavior. In this note, we prove certain similarities between this shaping algorithm and the initialization step required for several reinforcement learning algorithms. More specifically, we prove that a reinforcement learner with initial Q-values based on the shaping algorithm's potential function make the same updates throughout learning as a learner receiving potential-based shaping rewards. We further prove that under a broad category of policies, the behavior of these two learners are indistinguishable. The comparison provides intuition on the theoretical properties of the ...
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Emerging high-power microwave technologies require that bioeffects of exposure to this type of radiation be investigated for health and safety considerations. Disruption of animal behavior is reported to be a sensitive indicator of microwave exposure. Three behavioral tasks were chosen for this initial investigation of exposure to U.S. Air Force high-power microwave emitters. The tasks were: (1) single-trail avoidance, (2) water satiation, and (3) rotarod performance. Exposure to high-power microwave radiation from the USAFSAM peak-power simulator significantly affected the single-trail avoidance task. Neither the single-trail avoidance task nor rotarod performance was affected by the Gypsy emitter. However, animals exposed to 9-kW and 11-kW outputs from the USAFSAM emitter spent significantly less time imbibing water postexposure than sham-exposed animals. The most consistent finding in the animals exposed to the Gypsy pulses was that those ...
Prompt fission neutron energy spectra for "2"3"5U and "2"3"9Pu have been measured for fission neutron energies greater than the energy of the incident neutrons inducing fission. The measurements were undertaken to investigate the shape dependence of the fission neutron spectra upon both the incident neutron energy and the mass of the nucleus undergoing fission. Measurements were made for both nuclides at incident neutron energies of 0.50, 1.50, 2.50 and 3.50 MeV. The data are presented either as relative yields or as ratios of measured spectra to that of "2"3"5U at 0.50 MeV. Incident neutrons were produced by the "7Li(p,n)"7Be reaction using a pulsed, bunched proton beam from the 5.5 MV Van de Graaff accelerator at the University of Massachusetts Lowell Radiation Laboratory. Fission neutrons were detected by a thin liquid scintillator with good time resolution capabilities. Neutron energies were determined by time-of-flight techniques with ...
A new leaf-sequencing approach has been developed that is designed to reduce the number of required beam segments for step-and-shoot intensity modulated radiation therapy (IMRT). This approach to leaf sequencing is called continuous-intensity-map-optimization (CIMO). Using a simulated annealing algorithm, CIMO seeks to minimize differences between the optimized and sequenced intensity maps. Two distinguishing features of the CIMO algorithm are (1) CIMO does not require that each optimized intensity map be clustered into discrete levels and (2) CIMO is not rule-based but rather simultaneously optimizes both the aperture shapes and weights. To test the CIMO algorithm, ten IMRT patient cases were selected (four head-and-neck, two pancreas, two prostate, one brain, and one pelvis). For each case, the optimized intensity maps were extracted from the Pinnacle"3 treatment planning system. The CIMO algorithm was applied, and the optimized aperture ...
Using the linearized augmented-plane-wave (LAPW) -calculated electron and positron charge densities for YBa_2Cu_3O_7, the Brillouin-zone-reduced electron-positron momentum density is computed and the zone-reduced two-dimensional angular correlation of annihilation radiation (2D ACAR) spectrum is produced. The calculations show that the relative weights of the Fermi-surface discontinuities are substantially altered due to the positron preferentially sampling the Cu-O chain region. In addition, the reduced 2D ACAR spectrum contains large k-dependent wave-function effects. The theoretical zone-reduced 2D ACAR spectrum is compared to the several existing experimental spectra. It is concluded that, at present, positron-annihilation experiments do not provide consistent and clear evidence for the existence and shapes of Fermi surfaces in YBa_2Cu_3O_7.
We present a Hubble Space Telescope image of the FRII radio galaxy 3C 401, obtained at 1.6 microns with the NICMOS camera in which we identify the infrared counterpart of the brightest region of the radio jet. The jet has a complex radio structure and brightens where bending occurs, most likely as a result of relativistic beaming. We analyze archival data in the radio, optical and X-ray bands and we derive its spectral energy distribution. Differently from all of the previously known optical extragalactic jets, the jet in 3C401 is not detected in the X-rays even in a long 48ksec X-ray Chandra exposure and the infrared emission dominates the overall SED. We propose that the dominant radiation mechanism of this jet is synchrotron. The low X-ray emission is then caused by two different effects: i) the lack of any strong external photon field and ii) the shape of the electron distribution. This affects the location of the synchrotron peak in the ...
(abridged) The accretion disk in AGN is expected to produce strong outflows, in particular a UV-line driven wind. Despite providing a good fit to the data, current spectral models of the X-ray spectrum of AGN observed through an accretion disk wind are ad-hoc in their treatment of the properties of the wind material. In order to address these limitations we adopt a numerical computation method that links a series of radiative transfer calculations, incorporating the effect of a global velocity field in a self-consistent manner (XSCORT). We present a series of example spectra from the XSCORT code that allow us to examine the shape of AGN X-ray spectra seen through a wind, for a range of velocity and density distributions, total column densities and initial ionization parameters. These detailed spectral models clearly show considerable complexity and structure that is strongly affected by all these factors. The presence of sharp features in the ...
When chest radiographs are obtained using an anti-scatter grid in a mobile x-ray unit by Fuji Computed Radiography (FCR), right lung densities may differ from left lung densities owing to misalignment caused by an oblique x-ray beam. Such misalignment is considered to be caused by factors such as the shape of the bed and angle of the x-ray tube. Misalignment is especially frequent when exposure is carried out in the sitting position. Although a low-ratio grid has been reported to offer improvement, the misalignment is not completely eliminated. Therefore, we used a copper plate without a lattice feature instead of grid, and examined the results. The copper plate was found to have the ability of a grid to eliminate radiation scatter, and, furthermore, to offer the physical capabilities of a grid as determined by Carlin's new grid assessment method. Image quality was demonstrated through contrast manipulation to be equal to that obtained ...
When chest radiographs are obtained using an anti-scatter grid in a mobile x-ray unit by Fuji Computed Radiography (FCR), right lung densities may differ from left lung densities owing to misalignment caused by an oblique x-ray beam. Such misalignment is considered to be caused by factors such as the shape of the bed and angle of the x-ray tube. Misalignment is especially frequent when exposure is carried out in the sitting position. Although a low-ratio grid has been reported to offer improvement, the misalignment is not completely eliminated. Therefore, we used a copper plate without a lattice feature instead of grid, and examined the results. The copper plate was found to have the ability of a grid to eliminate radiation scatter, and, furthermore, to offer the physical capabilities of a grid as determined by Carlin's new grid assessment method. Image quality was demonstrated through contrast manipulation to be equal to that obtained by grid ...
Low-frequency current noise and current-voltage (I-V) characteristics have been studied in InAs/GaAs self-assembled Quantum Dot Infrared Photodetectors in dark conditions and under illumination, at T = 77K and T = 5K. The noise behavior is consistent with a generation-recombination fluctuation process mainly related to thermally excited charge carriers at T = 77K. At T = 5K the current noise is consistent with a mechanism of fluctuations driven by the electric field, related to tunneling rather than emission-capture of charge carriers from the Quantum Dots. A very effective noise suppression mechanism, related to the tunneling regime, determines a decrease of fluctuation intensity as a function of the voltage. At T = 5K, an interesting behavior is observed in the current-voltage and noise power spectra for some of nominally identical QDIP structures in the presence of irradiation. Some devices indeed exhibit (i) a very high photoresponse and (ii) a 1/f-shaped noise ...
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 interrogation tool to provide ...
Aims. We attempt to detect starlight reflected from a hot Jupiter, orbiting the main-sequence star HD 75289Ab. We report a revised analysis of observations of this planetary system presented previously by another research group. Methods. We analyse high-precision, high-resolution spectra, collected over four nights using UVES at the VLT/UT2, by way of data synthesis. We try to interpret our data using different atmospheric models for hot Jupiters. Results. We do not find any evidence for reflected light, and, therefore, establish revised upper limits to the planet-to-star flux ratio at the 99.9% significance level. At high orbital inclinations, where the best sensitivity is attained, we can limit the relative reflected radiation to be less than e = 6.7 x 10-5 assuming a grey albedo, and e = 8.3 x 10-5 assuming an Class IV function, respectively. This implies a geometric albedo smaller than p = 0.46 and p = 0.57, for the grey albedo and the Class IV albedo ...
The thermal neutron column of the JRR-2 reactor was remodelled in order to install a medical irradiation facility. The design experience and the cource of this remodelling are presented. At first, the thermal neutron flux was lower than expected, and the expected radiation condition was achieved by the following improvements: (1) removal of graphite from the thermal neutron column to increase the neutron flux, (2) twice increase of bismuth shielding and the shift of its position to improve the shielding effect against gamma ray, (3) application of B{sub 4}C rubber on the both surfaces of the shielding door to suppress the secondary gamma ray generation from the structural materials, (4) LiF tiles are applied on the inner face of the neutron beam exit hole to suppress the secondary gamma ray from the beam exit, and (5) installment a cone-shape polyethylene collimator to relieve the decay of thermal neutron. After the improvements, medical ...
Awaiting new data from RERF, an attempt was made to estimate the somatic risks of low doses of radiation for members of the German public. The new estimate follows closely the approach used in deriving the values published in the NIH Radioepidemiological Tables. The lifetime risk factors thus calculated are significantly larger than the estimates presented in ICRP Report 26 and are consistent with estimates recently made in the ongoing reactor safety study of NUREG. The increase in lifetime risks is mainly due to the introduction of a new time projection model which appears to be more consistent with the epidemiological data for many late effect end points than the constant absolute risk model previously employed. Results from a study in which epidemiological data were stochastically simulated with a computer indicate that the shapes of actual dose effect curves might be significantly more influenced by pure chance than by the dose dependency ...
A lock out assembly for a circuit breaker which consists of a generally step-shaped unitary base with an aperture in the small portion of the step-shaped base and a roughly S shaped retaining pin which loops through the large portion of the step-shaped base. The lock out assembly is adapted to fit over a circuit breaker with the handle switch projecting through the aperture, and the retaining pin projecting into an opening of the handle switch, preventing removal.
The most classic information on the syntrophic microorganisms in an anaerobic bacteria symbiotic system may be methanobacillus omelianskii. These bacteria were isolated as ones degrading alcohols such as ethanol into methane and were stably preserved for more than 20 years. But, it was clarified by later researches that this was a kind of symbiotic cocultivation system of the bacteria (S strain) which oxidizes ethanol into acetic acid, hydrogen, and carbon dioxide, and a kind of bacteria of the methanobacterium genus which produces or synthesizes methane from hydrogen and carbon dioxide. Such a symbiotic system of two kinds of anaerobic bacteria is the one of a kind of bacteria which produces hydrogen by oxidizing substances and of another kind of bacteria which consume hydrogen. Various kinds of symbiotic systems including those of animal-and-bacteria, and ...
... hypersonic aerodynamic force, or the space-equivalent region. Some of these experiments change the X-15 from a research airplane to a kind of space probe, ...
The growth power-time curves of a strain of petroleum bacteria, B-2, in various kinds of cultures containing different kinds of carbon sources, glucose, n-tetradecane, n-hexadecane and n-octadecane, and different kinds of microemulsions have been determined by using a 2277 Thermal Activity Monitor. The curves showed a single peak for cultures containing a single carbon source, glucose, and two peaks for cultures containing two kinds of carbon sources, glucose and one of the n-alkanes. The first peak indicated that bacteria grew by consuming glucose and the second peak indicated that bacteria grew by consuming n-alkane. The curves were complex when the bacterium grows in a microemulsion culture. According to a kinetic equation of bacterial growth under limited conditions, the rate constants of bacterial growth were obtained. The results showed that the microemulsion culture was more appropriate to ...
In this report, I surveyed the cognitive radio technique in wireless networks. Researched several kinds of cognitive techniques about their advantages and disadvantages.
... In a first-of-its-kind operation, Lisnave recently converted Latvian Shipping Company's 20,000 dwt products tanker Dzintari into a full Class 3 ...
...policy issues global warming global climate change ? there's a famous hockey ...global warming the greatest hopes for betray them and kind of forgotten ...
"Machines of all kinds depend on complex software to keep them operating safely. But how reliable is the software - and how can we be sure it is reliable?" (4 pages)
Several recent improved methods for the EGFM are introduced in order to avoid artificial holes seen in the synthetic acceleration spectrum. Furthermore evaluation of input ground motions at Wolsung NPP are performed by varying the source parameters that may control the high-frequency wave radiation and the deviation of the synthetic motions are revealed. The PSHA case studies for four NPP sites (Wolsung, Kori, Uljin, Younggwang) are performed. In the analysis, site-specific attenuation equations developed for Korean NPP sites are employed, and the seismic hazards for the target sites are evaluated in the case where the four kind of seismic source models are considered. Moreover, the PSHA for Wolsung and Younggwang are conducted by using the site-specific attenuation equation with the index of response spectra and the uniform hazard spectra are evaluated for the two sites. The supporting tool for seismic response analysis and the evaluation tool ...
The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in 192Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an 192Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the +-3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement ...
The Physikalisch-Technische Bundesanstalt (PTB), Germany's national metrology institute, developed an alignment strategy to specify elemental depth profiling in vertical sidewall layers on structured wafers. For this purpose, PTB's irradiation chamber for 200 mm and 300 mm silicon wafers was used to combine total-reflection X-ray fluorescence (TXRF) and grazing incidence XRF (GIXRF) techniques by employing monochromatized undulator radiation of the BESSY II electron storage ring. 3-D test structures were fabricated to develop an optimal alignment strategy allowing for depth profiling in such nanolayers. The test structures consisted of silicon bars with widths/spacings either in the {mu}m or in the nm range. In order to be able to differentiate the sidewalls more easily from the remainder of the structures, they were provided with an additional silicon nitride layer. Four structure types of different bar width and density parameters on two 200 mm ...
The Physikalisch-Technische Bundesanstalt (PTB), Germany's national metrology institute, developed an alignment strategy to specify elemental depth profiling in vertical sidewall layers on structured wafers. For this purpose, PTB's irradiation chamber for 200 mm and 300 mm silicon wafers was used to combine total-reflection X-ray fluorescence (TXRF) and grazing incidence XRF (GIXRF) techniques by employing monochromatized undulator radiation of the BESSY II electron storage ring. 3-D test structures were fabricated to develop an optimal alignment strategy allowing for depth profiling in such nanolayers. The test structures consisted of silicon bars with widths/spacings either in the ?m or in the nm range. In order to be able to differentiate the sidewalls more easily from the remainder of the structures, they were provided with an additional silicon nitride layer. Four structure types of different bar width and density parameters on two 200 mm silicon wafers were ...
The aim of this study is to prepare some polymeric moulds using Natural rubber latex (NRL)- portland cement composites based on a delayed-action mechanism. Factors affecting the preparation process such as concentration, mixing percentage, additives and their effects on what is regarded as a delayed-action coacervant combination was studied. The effect of Gamma-radiation on the mechanical properties of these moulds was investigated. The effect of natural aging on the prepared moulds was investigated to determine the possibility of using the prepared product in the construction field as expansion joints and cracks filling materials ...etc. The results may be summarized as follows: 1) Composites of natural rubber latex (NRL)-portland cement mould were prepared as two separate parts. The stabilized natural rubber latex (NRL) with hydroxy ethyl cellulose (HEC) as stabilizer and a delayed-action coacervant (sodium meta silicate) present in the rubber mixture was ...
Processing certain raw materials containing natural radioactive isotopes (e.g. U-238, Th-232 or K- 40) into products such as glas, abrasives, grinding materials or electrodes used for gasshielded tungsten-arc welding also leads to certain concentrations of industrial waste containing natural radioactive materials. Such industrial waste does not necessarily contain natural radioactive substances in concentrations exceeding the highest possible levels but nevertheless in significantly measurable quantities. This, however, frequently leads to confusion bordering on irritation by entities processing such substances as well as the general public, since they tend to believe natural radioactive substances in unobjectable concentration to cause similar or identical - health - consequences as man made radioactive substances in detrimental concentration. Radioactive materials may be incorporated intentionally or unintentionally into the product as main or additional ingredients. The recent ...
Processing certain raw materials containing natural radioactive isotopes (e.g. U-238, Th-232 or K- 40) into products such as glas, abrasives, grinding materials or electrodes used for gasshielded tungsten-arc welding also leads to certain concentrations of industrial waste containing natural radioactive materials. Such industrial waste does not necessarily contain natural radioactive substances in concentrations exceeding the highest possible levels but nevertheless in significantly measurable quantities. This, however, frequently leads to confusion bordering on irritation by entities processing such substances as well as the general public, since they tend to believe natural radioactive substances in unobjectable concentration to cause similar or identical - health - consequences as man made radioactive substances in detrimental concentration. Radioactive materials may be incorporated intentionally or unintentionally into the product as main or additional ingredients. The recent ...
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 ...
A laser resonance absorption spectrometer is used to investigate the characteristics of both self and nitrogen collision broadened carbon dioxide in resonance with He--Ne laser radiation at 4.2 ..mu..m. The absorption coefficient in these broadening conditions has contributions from the R(28) to R(34) absorption lines of the ..nu../sub 3/ CO/sub 2/ spectrum. The Fletcher-Powell optimization method is used to reduce the raw absorption data and to find the best value average collision broadening coefficient and laser emission frequency for a Lorentzian line shape model of the contributing lines. Pure carbon dioxide absorption in a pressure range of from 0.0016 atm (1.25 Torr) to 0.33 atm (250 Torr) is described well by the model with an average self broadening coefficient of 0.084 +- 0.008 cm/sup -1/ atm/sup -1/ for laser frequencies located at either 2370.591 +- 0.020 cm/sup -1/ or 2371.135 +- 0.019 cm/sup -1/. Nitrogen broadened carbon dioxide ...
Purpose/Objective: At present, treatment verification between portal and reference images is performed based on manually-identified features by radiation oncologist, which is both time-consuming and potentially error-prone. There is a demand for the computerized verification procedure in clinical application. The purpose of this study is to develop a computerized portal verification scheme for pelvic treatment fields. Materials/Methods: The automated verification system involves image acquisition, image feature extraction, feature matching between reference and portal images and quantitative evaluation of patient setup. Electronic portal images with a matrix size of 256 x 256 and 12 bit gray levels were acquired using a liquid matrix electronic portal imaging device. Simulation images were acquired by digitizing simulation films using a TV camera into images with 256 x 256 matrix and 8 bit gray levels. Initially a Canny edge detector is applied to identify the ...
We investigate ordering properties of two-dimensional granular materials using several shapes created by welding ball bearings together. Ordered domains form much more easily in two than in three dimensions, even when configurations lack long-range order. The onset of ordered domains occurs near a packing density of 0.8, a phenomenon observed previously for disks. One of our shapes, the trapezoid, has packings that remain disordered and near the transition density even after annealing by shaking. Although random packings are unstable for disks and many other shapes in two dimensions, trapezoid packings provide an approach to studying two-dimensional randomness. We also find that the rotational symmetry of a shape is an excellent predictor of how easily it orders, and a potential guide to identifying two-dimensional shapes that remain random after annealing.
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
... radiation during clinical therapy and exposures due to radiation accidents or attacks, in which the doses are uncontrolled ... only be used off-label in victims of radiation accidents or attacks. The idea...
This paper is concerned with the application of a new fuzzy inference method to the design of fuzzy power system stabilizer. Based on Truth-Value-Flow-Inference (TVFI), a fuzzy logic controlled power system stabilizer is proposed to enhance the stability of power system with weak or negative damping. The design of the proposed fuzzy power system stabilizer is presented. Numerical simulation results are presented and compared with two other kinds of fuzzy power system stabilizers. (author)
Effects of gamma irradiation on hygienic quality and extraction yields in twenty-one kinds of Korean medicinal herbs were investigated. Gamma irradiation at 5-10 kGy inactivated contaminating microorganisms. The total extraction yield in fifteen kinds of the investigated medicinal herbs increased by 5-25% by a dose of 10 kGy. (author)
A robust technique for determining the principal axes of a 3D shape represented by a point set, possibly with noise, is presented. We use techniques from robust statistics to guide the classical...Full Text Available
The shapes of dendritic arbors are fascinating and important, yet the principles underlying these complex and diverse structures remain unclear. Here, we analyzed basal dendritic arbors of 2,171 pyramidal...Full Text Available
An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.
of increasing numbers of vortices as a function of the thickness. Vortices are these whirlpool shaped structures. They are interesting because they come paired with...
A working group (SC 45B/WG B8) exists within the international electrochemical commission (IEC) which is working on the combination and revision of the IEC standards 61283, 61323, 61344, 61525 and 61526. All these standards concern direct reading, electronic, personal dose equivalent meters for the quantities H{sub p}(10) and H{sub p}(0,07); they are different with regard to the kind of radiation (photons, and/or beta rays and/or neutrons). The new standard with the number 61526 shall cover the following topics: 1. Combination of all the mentioned standards; 2. Maintenance of the essential requirements of the former standards; 3. Inclusion of the determination of the uncertainty of measurement for the measured dose equivalent value according to the ''Guide to the Expression of Uncertainty in Measurement''; 4. Consideration of all the relevant ISO-standards for reference radiation fields ...
Evidence for triaxial nuclear shapes from families of unique-parity states in transitional odd-A nuclei around mass A=190 and A=130 is reviewed. The experimental data are analysed within the odd-A triaxial core model. Regular two-dimensional band patterns are found in experiment and are shown to be a consequence of broken axial symmetry. Recent theoretical developments are discussed including the question of how stable the triaxial shapes are.
The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of [sup 87]Mo are studied in detail and explained by the evolution of the [gamma]-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N [>=] 47 for the spherical shape of the Mo isotopes. (orig.)
The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of "8"7Mo are studied in detail and explained by the evolution of the #gamma#-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N #>=# 47 for the spherical shape of the Mo isotopes. (orig.).
The effect of WC particle size with the addition of VC as a grain growth inhibitor was investigated during the liquid phase sintering of WC-Co system. With increasing WC particle size at the same VC content, the effect of grain growth inhibition was increased. Also, with increasing the VC content, the grain shape of WC was changed from the faceted shape to the distorted shape, and the step density of the WC grain was increased. (orig.)
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).
Systematics of neutron capture radiative width were studied in the target element range from Th to Cm. Reduced radiative widths were analyzed with a simple radiative width formula based on E1 transition. Average radiative width is presented with the standard deviation of 15%. (author)
A new band gap profile (exponential profile) for the active layer of the a-SiGe:H single junction cell has been designed and experimentally demonstrated. In this paper we compare its optical and electrical characteristics with the two more common profiles: the U- and V-shapes. As predicted by the simulations, the new profile combines the advantages of both profiles. Like the V-shape, the exponential shape reduces the amount of Ge in the i-layer, decreasing both the space charge defect density inside the i-layer and the recombination losses. It also improves the electric field. At the same time, the exponential shape generates the same current density as the U-shape.
A focused ion beam (FIB) is used to accurately sculpt predetermined micron-scale, curved shapes in a number of solids. Using a digitally scanned ion beam system, various features are sputtered including hemispheres and sine waves having dimensions from 1-50 {micro}m. Ion sculpting is accomplished by changing pixel dwell time within individual boustrophedonic scans. The pixel dwell times used to sculpt a given shape are determined prior to milling and account for the material-specific, angle-dependent sputter yield, Y({theta}), as well as the amount of beam overlap in adjacent pixels. A number of target materials, including C, Au and Si, are accurately sculpted using this method. For several target materials, the curved feature shape closely matches the intended shape with milled feature depths within 5% of intended values.
Since it was introduced in the early 1940's, mutation breeding has been tested on many crops as modern plant breeding. Until now, more than seven hundred varieties have been developed by means of induced mutation, and many of them officially released and approved for registration. Hundreds of papers report the results of mutation breeding, and the characteristics of induced mutation in different kinds of crops were discussed for review purposes (Blixt and Gottschalk 1975, Gottschalk and Wolff 1983). Considering the results already obtained, it can be concluded that the kinds of induced mutation and their utilization vary from crop to crop. This paper summarizes and discusses the mutation characteristics and kinds on the induced mutants of leguminous plants that have been released.
To suit the needs of development for manufacture VLSI, we started to investigate liquid metal ion sources (LMIS) and focused ion beam (FIB) in 1984. Many kinds of emitters viz. neddle type, co-axial type and capillary type of Ga and Au LMIS and three kinds of eutectic alloys LMIS (Au-Si, Au-Si-Be, Pd-Ni-Si-Be-B) have been tested. A program which can calculate focused ion guns has been written. Four kinds of foused ion guns have been operated, a fine beam with diametic 0.1 #mu#m is obtained. Using the FIB a scanning ion microscope has been constructed. Some tests of etching and self-developing of nitrocellulose are described. (author).
One of the refinements of modern Nuclear Medicine is the capacity of providing dynamic and kinetics images of the administered radiopharmaceutical, reproducing its transport mechanism, action sites, receptor binding and excretion route. With the continues technological advances new radiopharmaceuticals have been developed in order to express higher specificity and with higher characters of affinity between receptor/complex. One radiopharmaceutical is formed by a reagent or bio molecule that has in its structure a radioisotope, that has the objectives of carrying it to the organs of affinity or to benign or malign tumoral process. Somatostatin inhibits the growing and proliferation of several tumoral cells. Somatostatin analogs bind to somatostatic receptors that are expressed in different kind of neoplasia DOTA-LANREOTIDE (DOTALAN) is an octapeptide analog to somatostatin. The interest of labeling the bio conjugate with gallium-67 in Nuclear Medicine comes from its ...
An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the ...
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)
A new generation of quasimonochromatic high-flux X-ray sources, based on the X-ray radiation produced through Compton scattering between an electron beam and a laser beam, is under development. One of the possible applications of this source is inline phase contrast mammography, based on the observation of the edge-enhancement effect that can be observed at the border of structures inside the breast in images produced using a partially or totally coherent X-ray beam. In this work we present the results of a set of simulations of inline phase contrast mammography using typical inverse Compton scattering sources parameters. The simulated sample was a tumour-like mass having spherical shape, diameter between 200 {mu}m and 5 mm, placed inside a breast-like matrix, 4 cm thick, and a standard composition of 50% glandular tissue and 50% adipose tissue. We discuss the minimum requirements for mammography using inverse Compton scattering sources and we ...
The slow or stagnant rate of nuclear power generation development in many developed countries over the last two decades has resulted in a significant shortage in the population of mid-career nuclear industry professionals. This shortage is even more pronounced in some specific areas of expertise such as radiological protection, waste management and decommissioning. This situation has occurred at a time when the renaissance of nuclear power and the globalization of the nuclear industry are steadily gaining momentum and when the industry's involvement in international and national debates in these three fields of expertise (and the industry's impact on these debates) is of vital importance. This paper presents the World Nuclear Association (WNA) approach to building and enhancing worldwide industry cooperation in radiological protection, waste management and decommissioning, which is manifested through the activities of the two WNA working groups on radiological protection (RPWG) and on ...
Full text: Production: This radio iodine produced by three methods: 1) Wet method: The irradiated tellurium is dissolved in an oxidizing mixture which also converts iodine in to iodide. This is a chemical method and iodine that it produced with this method has low purity and efficiency. 2). Dry Method: The irradiated tellurium is dissolved in furnace (750 deg. C) with sublimation method and iodine absorbed in sodium solution . In this case we have more than 99.5 % purity and 80 % efficiency. We are using this type in Iran. 3) Fission fragment method: In this case the iodine separated from fission fragment directly and we have high purity (career free) and specific activity of iodine. Application: Iodine is a versatile tracer element. It is used to determine thyroid cancer metastases, and size, shape and activity of the thyroid gland. Critical organ of iodine is thyroid gland. One of the common diagnostic procedures for determining thyroid function therefore, is to ...
(1) Young chrysanthemums were planted after being irradiated at the time of shoot tip culture and the influence of irradiation was evaluated from the point of view of establishment of mutants. (2) Two cultivars, Kin-tenryu and Tenryu-no-asa were used in this experiment. The percentage of cultivars healthy enough to transplant on June 10, 1972 showed a decrease in proportion to the increase of dosage. Some plants of cultivar Kin-tenryu died after being transplanted. (3) Few plants of either cultivar could overwinter, and in particular no plant irradiated by gamma-rays of 20 kR. (4) Plant height showed a tendency of inhibition in both cultivars. (5) Three chlorophyll mutants showing chimera appeared. One of them was in the cultivar Tenryu-no-asa irradiated by 10 kR at 3 days after planting; two of them were in the cultivar Tenryu-no-asa irradiated by 10 kR at 5 days after planting. One mutant exhibiting malformation of entire leaves appeared in the cultivar Kin-tenryu irradiated by 20 kR ...
This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where ...
A balloon-borne instrument has measured the cosmic-ray antiproton flux between 130 and 320 MeV and searched for antihelium between 130 and 370 MeV per nuclear. These particles were selected from the background of normal-matter cosmic rays by combining a selective trigger with a detailed spark chamber visualization of each recorded event. Antiprotons are identified by their characteristic annihilatin radiation. Residue from background processes meeting the selection criteria is small. The observed 14 antiprotons yield a measured differential flux of 1.7 +- 0.5 x 10/sup -4/ antiprotons m/sup -2/ sr/sup -1/ s/sup -1/ MeV/sup -1/ at the top of the atmosphere. The corresponding antiproton/proton ratio is 2.2 +- 0.6 x 10/sup -4/,, only slightly smaller than the ratio observed by other experiments at higher energies. Thus the antiprotons have a spectral shape similar to the protons, at least down to about 100 MeV. The expected flux of these particles ...
Spectral room temperature photoluminescence (pl) of polycrystalline Cu(In,Ga)Se2 films (CIGSe) is evaluated with respect to optoelectronic properties and in particular for the determination of the splitting of quasi-Fermi levels (EFn - EFp). For lateral resolution of ? 1 ?m a confocal pl-setup is used. The depth profile of the excess carrier densities determining the rates of radiative transitions strongly govern the spectral pl-shape which has been numerically modeled with a matrix transfer formalism. In this optical approach we discriminate for wave propagation and attenuation in a multilayer system between a plane-wave ansatz and a 3D-spherical formalism, depending on excitation area large or small/similar compared to the thickness of the absorber. In both cases re-absorption of photons in energetic regimes with absorption approaches unity, from which the splitting of the quasi-Fermi levels is preferentially deduced, substantially influence ...
Purpose: The aim of this study was to create, perfect and test a hyperthermia balloon catheter for local treatment of cholangiocarcinoma. The device should induce hyperthermia in tumor tissue by acting locally in the bile duct lumen in contact with the tumor-infiltrated duct wall. In addition, it should exert tissue compression to cause an appreciable reduction in tumor microvasculature flow, thus improving thermal performance. Methods: According to the design specifications, the working temperature range should allow the device to be used for hyperthermia therapy either in combination with radiation and/or chemotherapy(radio/chemo-sensitizing effect at 42-45 deg. C) or alone (induction of coagulation necrosis above 65 deg. C). The balloon serves as an anchoring system during treatment and as a functional element to induce tissue compression. In vitro mechanical evaluation of the pressure/volume relationship, with the balloon inside rigid walled conduits, was ...
The boundary-integral equation method is well suited for the calculation of the dynamic-stiffness matrix of foundations embedded in a layered visco-elastic halfspace (or a transmitting boundary of arbitrary shape), which represents an unbounded domain. It also allows pile groups to be analyzed, taking pile-soil-pile interaction into account. The discretization of this boundary-element method is restricted to the structure-soil interface. All trial functions satisfy exactly the field equations and the radiation condition at infinity. In the indirect boundary-element method distributed source loads of initially unknown intensities act on a source line located in the excavated part of the soil and are determined such that the prescribed boundary conditions on the structure-soil interface are satisfied in an average sense. In the two-dimensional case the variables are expanded in a Fourier integral in the wave number domain, while in three ...
Angle resolved valence shell photoelectron spectra of chloromethane and iodomethane have been recorded using synchrotron radiation in the photon energy range 14-120eV. These have allowed photoelectron angular distributions and branching ratios to be determined not only for the main bands associated with the single-hole states but also for the satellite structure due to many-electron effects. The continuum multiple scattering approach has been used to calculate photoelectron asymmetry parameters and branching ratios for the valence orbitals of CH_3Cl and CH_3I, and also for the I 4d subshell. A comparison between the experimental data and the theoretical predictions has enabled the influence of Cooper minima, shape resonances and intershell coupling to be assessed. The asymmetry parameters and branching ratio for the spin-orbit split components of the CH_3I"+X-bar "2E state have been measured and exhibit a spectral behaviour almost identical to ...
Under support from the French Space Agency (CNES), a 3D+t dusty-gas model of Comet 67P/Churyumov-Gerasimenko is being developed, to compute, from the first 2014 Rosetta orbital data, the aerodynamic forces exerted on the Rosetta orbiter and on the descent lander. We report the recently developed dust dynamics part of the code. The multi-species (presently H2O and CO) gas code is optimized in terms of computational speed owing to the use of two complementary methods: (a) 3D+t Direct Simulation Monte Carlo (DSMC) runs in the non-equilibrium regions adjacent to the surface and very distant from it, and (b) solutions of the Navier-Stokes equations in-between. The model is used presently using Lamy et al. (Space Sci. Rev., 2007, 128, 23) coarse information on 67P nucleus shape and rotation, and a range of possible gas production rates Q for the early Rosetta observations at rh 3 AU (Q 1026 - 1027 s-1). In the interim version, simplifying assumptions are made with ...
Quantum computers hold great promises for the future of computation. In this paper, this new kind of computing device is presented, together with a short survey of the status of research in this field. The principal algorithms are introduced, with an emphasis on the applications of quantum computing to physics. Experimental implementations are also briefly discussed.
Indomethacin, a potent nonsteroidal anti-inflammatory drug, has been used in the treatment of various kinds of pains, inflammation and arthritis. However, oral administration of indomethacin produces...Full Text Available
BackgroundSeveral kinds of anti-oxidants have drawn a lot of intension for their benefits on vascular protection. In addition, it has been demonstrated that exercise training could...Full Text Available
Background and AimsThere has been little previous work on the toughness of the laminae of monocots in tropical lowland rain forest (TLRF) despite the potential importance of greater...Full Text Available
This bibliography deals with the foundation of offshore structures like drilling or working platforms (oil and gas exploitation) or offshore tanks. Different kinds of foundations, e.g. pile foundations or shallow foundations, are described. Aspects of soil-structure interaction, engineering geology and soil mechanics are also discussed. (orig.).
Transitions at 28-32°C in membranes of many kinds of seeds influence their germination and subsequent growth. Changes at 28-32°C in the rates of loss of endogenous amino acids from imbibed...Full Text Available
Determine the degree to which different precautionary themes are dominant in various target populations and how these themes are acquired. Assess cultural signals of potential danger: are there different kinds of potential danger in different cultures. Do...
The paper deals with sixteen cases of acetabular fractures studied with CT. After a short description of the normal CT findings, the different kind of fractures are reported. The usefulness of CT examination in evaluating acetabular fractures and their complications is confirmed both in conservative treatment and surgical approach.
German translation of the publication 'The evaluation of risks from radiation' published in 1965 by the International Commission on Radiological Protection. In a survey, genetic and somatic risks from radiation are presented and explained. (HP).
This book gives an overview of the entire field of radiation protection with the subject areas radioactivity, X-rays, UV radiation, laser beams and high-frequency electromagnetic fields. It deals graphically with the most important physical notions, the incidence, origin, properties and biological effects of types of radiation, administrative and practical protection measures and the code of rules governing them. Apart from fundamentals of radiation protection the emphasis on the following: natural radiation exposure, radiation exposure to radon, disaster relief plans in the environment of nuclear plant, the precautionary radiation protection system evolved after Chernobyl, radiation exposure through UV radiation devices, radio, RF communication, radar, microwave ovens and high-voltage transmission ...
The esterification reaction of a long-chain fatty acid and a fatty alcohol catalyzed by sugar ester-modified lipases in organic media was studied. The reaction activity was improved when the lipases were modified with sugar esters. Among four kinds of sugar esters and six kinds of lipases, lipase CES modified with sugar ester SE-7 showed the highest reaction activity. The pH, solvent and temperature on the reaction activity of SE-7 modified lipase CES were also studied. PMID:12142919
Red mud is a kind of alumina production, characterized by high content of fine-dispersion Fe, Al and Ti oxyhydrates; it is studied from the viewpoint of its application as a sorbent for Sr. The red mud specific surface constitutes 23-25 m"2/g, the density is of 3.3-3.4 g/cm"3 and the melting temperature is 1350-1370 deg C. It is established that the maximum sorption capacity of the red mud for strontium equals 420 #+-# 24 mg-eq/100 g. The red mud high sorption properties make it possible to recommend it as a sorbent by constructing technogenic barriers at the radioactive wastes disposal sites
The low alloy steels were nitrided in the plasma atmosphere generated by using hollow cathode discharge. For comparison, specimens of 40 Cr steel were in two different potential states. One kind is isolated from cathode and anode between them the discharge was created. The other kind is placed on the plate which is connected to the cathode. The nitriding was carried out at different temperatures. The surface morphology, phase of compound layers and microhardness profiles were analyzed. The optical microscopy observation and X-ray diffraction showed that the compound layers were formed in all experiments. The results of the nitriding treatment are weakly dependent on the potentials applied on the specimens.
This paper is intended to describe how the citizens who are living near power plants or more generally nuclear facilities can be involved in the radiological control of their environment. Through the experience of the last twenty years, the article describes the conditions of the progressive setting up of a non- governmental system of control to build its principles of action and put them into practice. Three kinds of actions are described, the first two dealing with the problems in France and the last one related to a post-accidental situation in the contaminated areas of Belarus. The conclusion underlines how important it is to encourage this kind of involvement in order to increase public awareness of nuclear activities and their consequences. (authors)
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.
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).
The bone mineral areal content and the ultimate compressive strength were determined in 109 lumbar vertebrae from 36 subjects. The bone mineral areal content was related to the number, shape, and localization of the Schmorl's nodes detected in the x-rayed and sectioned vertebral bodies. One type of node, irregular in shape and localization, occurred only in the vertebrae with low bone mineral areal content values and thus in vertebrae with relatively low compressive strength. A second type of Schmorl's nodes, regular in shape and localization, did not reflect any general weakness of the vertebral bodies. PMID:6623194
This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.
Spray forming is an advanced materials processing technology that converts a bulk liquid metal to a near-net-shape solid by depositing atomized droplets onto a suitably shaped substrate. By combining rapid solidification processing with product shape control, spray forming can reduce manufacturing costs while improving product quality. De Laval nozzles offer an alternative method to the more conventional spray nozzle designs. Two applications are described: high-volume production of aluminum alloy strip, and the production of specialized tooling, such as injection molds and dies, for rapid prototyping.
We study suspensions of semi-flexible colloidal rods and biopolymers using an Onsager-type second-virial functional for a segmented-chain model. For suspensions of thin and thick fd virus particles we calculate phase diagrams in quantitative agreement with experimental observations, and we find their effective state-point dependent shape to be much shorter and thicker than the actual shape. We also calculate the stretching of worm-like micelles in a host fd virus solution, again finding agreement with experiments. For both systems, our results show that the fd virus stiffness can play a key role in system behavior.
Micro-compression specimens, 1O-15{mu}m in diameter by 20-30{mu}m in height, were produced from individual parent grains in a polycrystalline U-13at%Nb shape-memory alloy using the focused ion beam (FIB) technique. The specimens were tested in a nanoindentation instrument with a flat diamond tip to investigate stress-strain behavior as a function of crystallographic orientation. The results are in qualitative agreement with a single-crystal accommodation strain (Bain strain) model of the shape-memory effect for this alloy.
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 ...
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Axon outgrowth and guidance to the proper target requires the coordination of filamentous (F)-actin and microtubules (MTs), the dynamic cytoskeletal polymers that promote shape change and locomotion....Full Text Available
... WHS- Washington Headquarters Service. ... US Military (ie, Army, Navy, Air Force) service publications ... Strike Group to Fight in the Joint Task Force. ...
We study some aspects of the experimental behaviour of tachyons, in particular by finding out their <> shape. A Superluminal particle, which in its own rest frame is spherical or ellipsoidal (and with an infinite lifetime), would <> to a laboratory frame as occupying the whole region of space bound by a double cone and a two sheeted hyperboloid. Such a structure (the tachyon <<shape>>) rigidly travels with the speed of the tachyon. However, if the Superluminal particle has a finite lifetime in its rest frame, then in the laboratory frame it gets a finite space extension. As a by-product, we are able to interpret physically the imaginary units entering - as is well known - the transverse co-ordinates in the Superluminal Lorentz transformations. The various particular or limiting cases of the tachyon shape are thoroughly considered. Finally, some brief considerations ...
Sensory systems must form stable representations of the external environment in the presence of self-induced variations in sensory signals. It is also possible that the variations themselves may provide...Full Text Available
Recent Kawasaki Steel's development on size and shape measurement techniques for hot steel rolling processes is reviewed. First, a precision enhancement technique for a laser distance meter is described, then its rugged structure necessary for measurement in such tough environment as hot rolling processes is described in detail. A plate length meters and an inter-stand sensors for a hot strip mill are shown as developed size measurement techniques. Furthermore, plate shape meters and laser profile gauges for H-beams are depicted as specific examples of shape measurement techniques. (author)
This report discusses: shape coexistence in {sup 184}Pt; nuclear structure of {sup 187}Ir; g-factors of excited states; OLNO-2; and refrigerator development.
This report discusses: shape coexistence in "1"8"4Pt; nuclear structure of "1"8"7Ir; g-factors of excited states; OLNO-2; and refrigerator development.
Our global impact is finally receiving the scientific attention it deserves. The outcome will largely determine the future course of evolution. Human-modified ecosystems are shaped by our activities...Full Text Available
This article examines how politics and science interacted against a background of uncertainty to shape policy in the case of environmental contamination by polybrominated biphenyls (PBB) in Michigan....Full Text Available
Even when a healthy individual is studied, his/her erythrocytes in capillaries continually change their shape in a synchronized erratic fashion. In this work, the problem of characterizing the cell...Full Text Available
During instrumentation of the root canal, it is important to develop a continuously tapered form and to maintain the original shape and position of the apical foramen. However, the presence of curvatures...Full Text Available
The bacterium Serratia marcescens produces a plethora of multicellular shapes of different colorations on solid substrates, allowing immediate visual detection of varieties. Such a...Full Text Available
This chapter is concerned with standards and guidances for limiting radiation exposures. It is divided into three sections, each of which has several parts. Section 1: Ionizing Radiation -- Standards and Guidances Applicable to the Public: Part A, Radiation Protection Standards; Part B, Environmental Radiation Standards; Part C, Exempt Levels of Radioactivity; Part D, Protective Action Guides for Accidents. Section 2: Ionizing Radiation -- Standards Applicable to the Workplace. Section 3: Medical and Other Standards.
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.
The current state and need for radiation protection training in Finland have been surveyed by the Radiation and Nuclear Safety Authority STUK. The survey sought to determine whether the current requirements for radiation protection training had been met, and to promote radiation protection training. Details of the scope and quality of present radiation protection training were requested from all educational institutes and organizations providing radiation protection training. The survey covered both basic and further training, special training of radiation safety officers, and supplementary training. The questionnaire was sent to 77 educational organization units, 66 per cent of which responded. Radiation workers and radiation safety officers were asked about radiation protection ...
New surface photometry of all known elliptical galaxies in the Virgo cluster is combined with published data to derive composite profiles of brightness, ellipticity, position angle, isophote shape, and color over large radius ranges. These provide enough leverage to show that Sersic log I #propor to# r "1"/"n functions fit the brightness profiles I(r) of nearly all ellipticals remarkably well over large dynamic ranges. Therefore, we can confidently identify departures from these profiles that are diagnostic of galaxy formation. Two kinds of departures are seen at small radii. All 10 of our ellipticals with total absolute magnitudes M_V_T #<=# -21.66 have cuspy cores-"missing light"-at small radii. Cores are well known and naturally scoured by binary black holes (BHs) formed in dissipationless ("dry") mergers. All 17 ellipticals with -21.54 #<=# M_V_T #<=# -15.53 do not have cores. We find a new distinct component in these galaxies: all ...
A method for the calculation of excitation functions and isomer ratios, for shape isomers, in heavy ion induced reactions is proposed. The calculated values of excitation functions and isomer ratios agree very well with the experimental values for the reaction /sup 238/U(/sup 11/B, alpha 3n)/sup 242/Am. (auth)
Computer simulations and experiments indicate that we can shape the infrared picosecond pulses of the Mark III FEL in amplitude, frequency, and phase. Strongly modulated fundamental and second harmonic pulses have been generated by operating the Mark III FEL in the regime of strong sideband growth. In this paper, we present the results of simulations and experiments for second harmonic generation with fundamental inputs from 2 to 3 {mu}m.
The neutron deficient Sr and Zr nuclei are studied in the relativistic mean-field approach. Large deformations and shape coexistence are predicted for these nuclei in the vicinity of the proton drip line. The charge radii are found to increase with the removal of neutrons from the semimagic {sup 88}Sr and {sup 90}Zr, in close agreement with the recent isotopic-shift measurements.
Large, complex, high purity ceramic shapes are required by a variety of emerging technologies for their electrical insulation and high temperature strength properties coupled with their refractoriness and purity. Ceramic sealant bonding, using crystalline and vitreous sealant materials, has recently shown significant potential for joining technical ceramics to form the required shapes. Materials and techniques for joining technical ceramics including alumina, magnesia, zirconia and thoria are discussed. (orig.).
A novel approach is presented to extract relevant parameters associated with the energy loss of ejectiles from nuclear reactions obtained by digitizing the signals of a Bragg curve spectrometer. New and more powerful computational paradigms allow a more thorough pulse-shape analysis. This is fulfilled using a back-propagation artificial neural network as a pattern identifier. The known problem of over-training is discussed.
Recently, the public has become aware of keywords like ''Quantum computer'' or ''Quantum cryptography''. Regarding their potential application in solid state based quantum information processing and their overall benefit in fundamental research quantum dots have gained more and more public interest. In this context, quantum dots are often referred to as ''artificial atoms'', a term subsuming their physical properties quite nicely and emphasizing the huge potential for further investigations. The basic mechanism to be considered is the theoretical model of a two-level system. A quantum dot itself represents this kind of system quite nicely, provided that only the presence or absence of a single exciton in the ground state of that structure is regarded. This concept can also be expanded to the presence of two excitons (bi-exciton). Transitions between the ...
The IAEA has requested several member states to present their proposal of the application of the Integrated Safeguards (IS) system in their nuclear facilities. This report contains a IS proposal for Finland prepared under the Task FIN C 1264 of The Finnish Support Programme to IAEA Safeguards. The comprehensive safeguards system of the International Atomic Energy Agency (IAEA) has been one of the main tools in the fight against nuclear proliferation since the entry-into-force of the Nuclear Non-proliferation Treaty three decades ago. In the 1990s some of the inherent weaknesses of this so-called traditional safeguards system were revealed first in Iraq and then in North Korea. Therefore, the member states of the LAEA decided to give the Agency additional legal authority in order to make its control system more effective as well as more efficient than before. This was accomplished by the approval of the so-called Model Additional Protocol (INFCIRC/540) in 1997. Straightforward ...
The assumed linear relationship between exposure to radiation and cancer incidence is questioned in this article. The current research data on radiation effects at the cellular level is reviewed, as are epidemiological studies of background radiation effects and health effects of populations exposed to low levels of radiation exposure via employment or medical treatments. Statistics reveal that threshold levels currently in force need to be reviewed. Some evidence of beneficial effects of low level radiation exposure effects of low level radiation exposure is also presented, and so regulations should be reviewed at an international level. (UK).
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.
This report describes the preliminary thermalhydraulic analysis of HTR-10 steady state full power initial core to provide a benchmark calculation of VHTGR(Very High-Temperature Gas-Cooled Reactors) safety analysis code of GAMMA(GAs Multicomponent Mixture Analysis). The input data of GAMMA code are produced for the models of fluid block, wall block, radiation heat transfer and each component material properties in HTR-10 reactor. The temperature and flow distributions of HTR-10 steady state 10 MW{sub th} full power initial core are calculated by GAMMA code with boundary conditions of total reactor inlet flow rate of 4.32 kg/s, inlet temperature of 250 .deg. C, inlet pressure of 3 MPa, outlet pressure of 2.992 MPa and the fixed temperature at RCCS water cooling tube of 50 .deg C. The calculation results are compared with the measured solid material temperatures at 22 fixed instrumentation positions in HTR-10. The wall temperature distribution in pebble bed core shows ...
For the step-and-shoot intensity-modulated radiation therapy (IMRT) technique, the combination of high dose rate, multiple beam segments and low dose per segment can lead to significant differences between the planned dose and the dose delivered to the patient. In this technique, a dose delivery inaccuracy known as the 'overshoot' effect is caused by the dose servo control system. This typically occurs in the first and last beam segments and causes an over- and underdose, respectively. Some dose positional error in the segment sequence is also possible there. Commercial ionization chambers (RK-type) and radiographic Kodak films were used for the measurements. The reported results were obtained using the Pinnacle{sup 3}-V6.2 treatment planning system and a Varian Clinac 21 EX linear accelerator equipped with a 120-leaf Millennium MLC. The dose inaccuracy measurements were based on the comparison of the dose and profiles for reference fields and ...
Er{sub 3}NbO{sub 7} phosphor was synthesized by sintering a mixture of Er{sub 2}O{sub 3} and Nb{sub 2}O{sub 5} powder in a molar ratio of 3:1 at 1600 deg. C over 55 h. Optical absorption and emission characteristics of Er{sup 3+} ions in the calcined Er{sub 3}NbO{sub 7} powder were investigated and discussed compared with ErNbO{sub 4} phosphor and a Z-cut congruent Er (2 mol%):LiNbO{sub 3} single crystal. The absorption and emission studies show that, due to different crystal structures, the spectroscopic properties of these niobates have some differences in spectral shape, peak position, and relative intensity, especially at 1.5 {mu}m. The most obvious spectral feature of the Er{sub 3}NbO{sub 7} is that the spectral structure of band instead of peak is observed in its absorption or emission spectrum due to the existence of local structural disorder and multiple Er{sup 3+} sites. The Er{sub 3}NbO{sub 4} shows stronger upconversion emission than the single crystal ...
Photometric and kinematic observations of the peculiar S0 galaxy IC 4767, the X-galaxy, are presented. At various intensities the bulge of this galaxy looks like a normal spheroidal system with elliptical isophotes, a well-defined rectangle, and a peanut-shaped or X-shaped structure with components aligned at oblique angles to the major axis. The observations reveal a rapidly rotating inner disk of gas and dust which is nearly aligned with the major axis. The presence of gaseous emission alone suggests an accretion event. The stars in the outer regions of the X-component are rotating nearly as rapidly as the gas in the main disk, indicating that they are in relatively circular orbits. The five most prominent peanut-shaped bulges all have several nearby companions, evidence that the peanut deformity is due to interaction between galaxies. An analogy with the formation mechanism proposed for polar-ring galaxies suggests how ...
We measured the volume of the supratentorial ventricles in 39 consecutive children with myelomeningocele (MMC) and associated hydrocephalus, using a stereological method based on the Cavalieri theorem of systematic sampling. We distinguished the following groups: newborns before and after cerebrospinal fluid shunting (14), a somewhat larger group of newborns with an untreated MMC-associated hydrocephalus (25) and a group of shunted children at a mean age of 1.5 years (28). We paid special attention to the shape of the lateral ventricles, looking separately at the anterior and posterior halves. The measurements were compared with a healthy control group (10) and with children with hydrocephalus unrelated to MMC (15). The average volume ratio of the posterior to the anterior half of the lateral ventricles was 1.05 #+-# 0.39 in non-hydrocephalic children, 1.11 #+-# 0.55 in untreated hydrocephalic children without MMC, and 2.15 #+-# 0.65 in MMC-associated hydrocephalus ...
In 1999, the plasma parameters of reversed shear (RS) plasmas had been extended in 1) DT-equivalent fusion power gain Q_D_T"e"q - 0.5 (n_D(0)#tau#_ET_i(0) - 4x10"2"0 m"-"3#centre dot#keV#centre dot#s) for 0.8 s and 2) full non-inductive current drive with 80% of the bootstrap current fraction. Physics of the internal transport barriers (ITBs) in RS plasmas, including the energy transport and the formation of ITB, were extensively studied. A nearly full current drive (92% non-inductively) was obtained with negative ion based neutral beam (NNB) injection (360 keV, 3.4 MW) in a high #beta#_p H-mode plasma (I_p=1.5 MA, B_T=3.7 T, q_9_5=4.2) with high plasma performance (#beta#_N=2.4 and H_8_9=2.56). Rise in the central electron temperature (T_e - 9 keV) resulted in the current drive efficiency #eta#_C_D of NNB reached 1.3x10"1"9 A/W/m"2, the highest for the neutral beam current drive. As for the H-mode plasmas, decrease in the pedestal ion temperature due to strong gas was found cause ...
Full text: Radiotherapy treatment planning (RTP) relies heavily on medical imaging. Until recently, the most important planning tool was the treatment simulator. The kilovoltage radiographic capabilities in a treatment simulator enabled the boundaries of treatment fields to be visualized with respect to bony anatomic landmarks. Perhaps the most important advance in treatment planning in recent years is the ability to visualize the passage of the beams with respect to a more accurate geometrical representation of the tumor and other soft tissue structures. This 'virtual simulation' uses a computer-based representation of a patient to determine the extent of the disease and the location of radiation sensitive normal tissue. Computer tomographic (CT) imaging produces a high-resolution three-dimensional representation of anatomy that can be correlated with other image sets such as magnetic resonance images (MRI) of function. Positron emission tomographic (PET) imaging ...
Coal ash is a substance that has been mixed into minerals in the earth`s crust during their coalification process. Estimation was made on what kinds of mineral composition have been mixed into coals. Noted first was the kinds of compounds contained in the ash, wherein the ratios of mass in the compounds and minerals were correlated, and selection was made on minerals which are thought correlated. The selection criterion was based on minerals containing silica, alumina, iron oxide, lime and magnesium as compounds. Then, a phase equilibrium line diagram was used to estimate compositions and melting points of minerals which are thought to have been produced from these compounds. By comparing the estimation with the measured melting points of the ashes, mineral compositions thought reasonable were all selected. Assumption was possible on minerals that are thought to have been transferred into coal ash. Compound indications of ashes from 29 ...
Many kinds of Evolutionary Algorithms (EAs) have been described in the literature since the last 30 years. However, though most of them share a common structure, no existing software package allows the user to actually shift from one model to another by simply changing a few parameters, e.g. in a single window of a Graphical User Interface. This paper presents GUIDE, a Graphical User Interface for DREAM Experiments that, among other user-friendly features, unifies all kinds of EAs into a single panel, as far as evolution parameters are concerned. Such a window can be used either to ask for one of the well known ready-to-use algorithms, or to very easily explore new combinations that have not yet been studied. Another advantage of grouping all necessary elements to describe virtually all kinds of EAs is that it creates a fantastic pedagogic tool to teach EAs to students and newcomers to the field.
Corrosion test, as a material selection test method of nozzle to be used in the marine diesel engine, was adopted and discussed. Due to the heightening in output power and lengthening in stroke of the marine diesel engine, the fuel injection nozzle became so severe in working condition that the nozzle tip became in lift 1/6 to 1/18 time as long as that of short stroke type in past. Then upon investigating cause of damage, the damage was confirmed to be mainly caused by the high temperature sulfidization corrosion. Then by preparing 20 kinds of candidate test piece and making sulfidization corrosion test in accordance with the high temperature corrosion test procedure, corrosiveness was evaluated through change in weight between before and after testing. As a result of testing, three kinds of test piece, inclusive of high Ni-Cr-Al alloy's, showed a high anti-corrosiveness. Those kinds of test piece were then field ...
The computer aided coal structure construction system is proposed, and a computational construction example is presented. The coal structure construction engine of this system fabricates molecular structure by connecting fragments sequentially inputted through a user interface. The best structure candidate is determined using construction knowledge and partial energy evaluation every addition of one fragment, and this process is subsequently repeated. The structure evaluation engine analyzes the 3-D conformation candidate by molecular dynamics, and evaluates the conformation by determining the energy value of an optimum structure. As an example, this system was applied to construction of coal molecular structure based on the actual data of partial structure composed of 26 structures from 2l kinds of aromatic cluster structures, 27 bonds from 2 kinds of bridged bonds, and 16 groups from 2 kinds of terminal substitutional ...
This manual was written for individuals who wish to become qualified in radiation protection as an adjunct to working with sources of ionizing radiation or using radionuclides in the field of medicine. It provides the radiation user with information needed to protect himself and others and to understand and comply with governmental and institutional regulations regarding the use of radionuclides and radiation machines. It is designed for a wide spectrum of users, including physicians, research scientists, engineers, and technicians. It should be useful also to radiation safety officers, members of radiation safety committees, and others who are responsible for the proper use of radiation sources, although they may not be working with the sources directly. The presentation in this manual is designed to obviate the need for reviews of atomic ...
Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...
The book examines current experimental and clinical knowledge concerning the biological and biophysical effects of electromagnetic radiation, particularly that in the microwave range. The biophysical bases of the interaction of electromagnetic radiation with matter are reviewed with emphasis on biological systems, and the effects of radiation on critical biological systems, including the nervous, reproductive, visual and blood-forming systems are compared. Data concerning the lethal effects of nonionizing radiation is presented and characteristics of the effects of electromagnetic radiation on the whole mammalian organisms are examined. Various reactions of the neuroendocrine system to electromagnetic radiation are described, with particular attention given to the adrenal system, and the combined effects of ionizing and microwave radiation ...
The biological age (BA) of the majority of the liquidators of the consequences of the radiation accidents in the Navy and of the liquidators of the Chernobyl' APS accident exceeds the medium standard and the DBA (due BA). The index of the BA can be a characteristic of the influence of the social-hygienic factors on the health condition of the Special Risk Subunit--the liquidators of the consequences of the radiation accidents. It was established, that the radiation influence concerns to the factors dramatically increasing the BA and the rate of senescence of the liquidators of the consequences of the radiation accidents. PMID:21809627
The experimental device for generation of undulator radiation in terahertz wavelength region by use of undulator with ferromagnets is created. The device is based on a beam of a microtron with the energy 7.5 MeV. The radiation wavelength is 200 mu. Registered spontaneous radiation has a power 10{sup -6} W at a current of a beam 2 mA in a pulse. With the optical resonator, in a mode, the amplification of 6% is received, that in sometimes is more than the expected value. This effect is explained as a result of partial coherence of radiation.
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation.
Characteristics of the Ukrainian NSA NRI radiation facility for scientific researches and developments of industrial radiation technology are performed. Parts of the facility, design peculiarities of technical tools are described. Biological protection of the facility and radiation protection system, transport line, systems of technical provision and radiation measurements are discussed
The radiation burden of the people of the GDR in relation to biomedical radiography altogether as well as organ doses, gonad doses and genetically significant doses in detail are outlined. The concepts of radiation protection and standards of radiographic examination are demonstrated. Possibilities of influencing radiation exposure by scientifically based indication of X-ray examination, application of new and improvement of usual examination techniques are discussed with regard to quality assurance and control. Proposals concerning the reduction of radiation exposure of the GDR population are presented.
High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.
Correlation characteristics of quantum noise on the shadow radiation image (RI) of the object under nondestructive testing are studied. Mathematical model of RI occasional distortions is derived. The model takes into account the parameters of object under testing and of radiation beam by radiation quanta flux density. The results obtained can be used as a component in the process of investigation of various radiation testing systems
Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.
Even the presence of very low concentrations of dyes (1mgL-1) in the effluent is highly visible and is considered aesthetically undesirable. It must be removed from wastewater completely. This study systematically evaluates the performance of adsorption (three kinds of powdered activated carbons), coagulation (AlCl36H2O) and membrane (submerged hollow fiber microfiltration) processes individually in treating two kinds of reactive dyes (Orange 16 and Black 5) and then using a hybrid process with combined coagulation-adsorption-membrane treatment system. Adsorption capacity and kinetics of Orange 16 were much higher and faster than those of Black 5. The dye removal efficiency by coagulation was highly dependent on dye concentration and solution pH. The hybrid process performance was far more...
Investment in mining projects is always associated with risk because of the inclusion of many uncertain parameters. Probability analysis can be applied to such a system which has many kinds of uncertain parameters. This kind of study uses historical data to provide more information for future decisions. This study uses the historical data from a truck-shovel operation at an open cut Coal Mine in NSW, Australia to develop a productivity estimation model, using stochastic analysis. In the first step statistics and various probability distributions were developed for both certain and uncertain variables. A correlation analysis was the next step to investigate any possible relationship between productivity and affecting parameters. The results of these two stages were then used in a simulation model using the stochastic approach. 2 figs.
Several experimental runs have been carried out to study nucleate boiling of binary mixtures consisting of Freon-11 and lube oils such as SUNISO 3GS and 4GS in oil concentrations ranging from 0 to 24% by volume. The effect of the heating source temperature on the rate of boiling at various pressures has been studied and the boiling curves at different oil concentrations and pressures have been investigated at an excess temperature of up to 80/sup 0/C. The experimental data have been used to find the effect of pressure, oil concentration and excess temperature on the boiling heat transfer coefficient. The P-T relations for both kinds of mixtures have been measured at different oil concentrations. The heat lost to the atmosphere have also been studied as a function of oil concentration for both kinds of mixtures.
Labelling of "1"4C-M-ISP and its absorption, translocation and distribution in peanut and soybean seedling were studied. The results of experiments showed that the radioactive substance could be translocated in xylem and phloem of two kinds of plants. The root of peanut seedling absorbed "1"4C-M-ISP from the nutrient solution more strong than the root of soybean seedling did. After leaf treatment with "1"4C-M-ISP, the soybean seedling absorbed more radioactive substance than peanut seedling did. But the translocation's speed of radioactive substance in pnloem of two kinds of plants were similar.
We report on the fabrication of nanomechanical devices for shuttling of electrons from one electrode to another. Each device consists of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. In two different kinds of shuttle-junctions the nanoparticle is attached to the electrodes through either (i) a single layer of 1,8-octanedithiol or (ii) a multilayer of 1-octanethiol molecules. The thiol layers play the role of 'damped springs', such that when a sufficient voltage bias is applied to the junction, the nanoparticle is expected to start oscillating and thereby transferring electrons from one electrode to the other. For both kinds of shuttle-junctions we observed an abrupt increase in the transmitted current above a threshold voltage, which can be attributed to a transition from the stationary to the oscillating regime. The threshold voltage was found to be lower for single-layer shuttle-junctions.
The early diagnosis of such disorders is of major importance because, in most cases, severe consequences can only be averted by early treatment. The value of magnetic resonance imaging (MRI) in many orthopaedic and traumatological conditions is generally accepted. The value of MRI in this particular field is illustrated by typical case reports on common clinical problems [Deutsch] Der Fruehdiagnose von Erkrankungen des Kindes- und Jugendalters kommt grosse Bedeutung zu, da oftmals nur durch eine daraus resultierende Fruehbehandlung schwerwiegende Folgen vermieden werden koennen. Die Kernspintomographie (Magnetresonanztomographie=MRT) ist in zahlreichen orthopaedischen-traumatologischen Fragestellungen bereits etabliert. An ausgewaehlten Fallbeispielen haeufiger klinischer Problemstellungen soll in der vorliegenden Arbeit der Stellenwert der MRT dargestellt werden. (orig.)
This paper aimed to the evaluation of different kinds of sorbent material preparation and to the evaluation of their characteristics at different pH conditions by X-ray fluorescence analysis. This method is suitable for identification and determination of elements in samples of different character, state and origin because it is a polycomponent, non-destructive, fast and simple analytical method. Moreover, it allows timeadvantageous and reliable measurements. This paper studies problems concerning the determination of some selected elements (Mn, Fe, Ni, Cu, Zn, Pb) in pharmaceutical samples of sodium chloride in the solid state as well as in its solution by sorption on chelating extraction membrane 3M Empore"T"M and on the strongly acidic ion-exchanger Dowex 50Wx8. Conditions for the most effective sorption of determined elements are also interpreted. (author)
This paper aimed to the evaluation of different kinds of sorbent material preparation and to the evaluation of their characteristics at different pH conditions by X-ray fluorescence analysis. This method is suitable for identification and determination of elements in samples of different character, state and origin because it is a polycomponent, non-destructive, fast and simple analytical method. Moreover, it allows time-advantageous and reliable measurements. This paper studies problems concerning the determination of some selected elements (Mn, Fe, Ni, Cu, Zn, Pb) in pharmaceutical samples of sodium chloride in the solid state as well as in its solution by sorption on chelating extraction membrane 3M Empore? and on the strongly acidic ion-exchanger Dowex 50Wx8. Conditions for the most ef...
Particle shape is an important parameter in numerous civil, environmental, and petroleum engineering applications. In ground-water flow, the shape of individual particles comprising the soil affects the soil`s pore size distribution and, hence, the important flow characteristics such as hydraulic conductivity and headloss. A model for delineating the relative importance of particle size, particle shape, and porosity, (and their interactions), in explaining the variability of hydraulic conductivity of a granular porous medium is developed and tested. Three types of porous media are considered in this work: spherical glass beads; granular sand; and irregularly shaped, shredded glass particles. A reliable method for quantifying the three-dimensional shape and packing of large samples of irregular particles based on their angle of repose is presented. The results of column experiments ...
A new type of radiation which occurs when particles are accelerated in the field of a longitudinal wave and in a transverse magnetic field is studied. The characteristics of such spontaneous radiation are obtained, and the influence of collective effects on the radiation is analyzed. The application of the findings to the theory of free electron lasers is discussed. 8 references.
Objectives To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental,...Full Text Available
Forty-four patients with histologically proven Hodgkin's disease underwent initial treatment with extended-field radiation therapy. Nineteen of these patients also received combination chemotherapy....Full Text Available
Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).
Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation...Full Text Available
Analytical method of theoretical simulation of collective hydrodynamic instabilities of intensive flows of discrete radiators, interacting with each other only through the coherent fields of their spontaneous radiation in corresponding media was suggested...
... Top of page Testing Radiation coming from granite countertops results from natural radioactive material in the granite. Identifying the presence and concentration of radioactive elements in granite requires expensive and sophisticated portable instruments or laboratory equipment. These instruments and equipment require proper calibration, and interpretation of ...
The different radiation loads caused by natural and artificial radionuclides are compared in this paper. This examples will serve to illustrate that the problem of population exposure to radiation can only be solved in consideration of all components and to show which effects of the radiation from natural sources are of special importance in this connexion. (orig./AK).
An optical klystron is built in the 800 MeV electron storage ring at University of Science and Technology of China for harmonic super-radiation generation. In single bunch operation mode the repetition rate of the spontaneous radiation pulses is about 4.533 MHz, and the repetition rate of the seed laser pulses is about 3 Hz, while the radiation pulse duration is 300 ps. For measuring harmonic radiation a high on/off ratio ICCD is used as an optical switch to reject spontaneous radiation pulses of high repetition rate
The document published under A/63:46 and titled report of the scientific committee of United Nations for the study of ionizing radiations effects, gives the situation of the fifty sixth session of the committee that stood at Vienna from the 10. to 18. july 2008. In the chapter 3 of this report the writers summarize the strategic planning and the working program of the scientific committee for the period 2009-2013. They note that the committee worry about the inadequate means, particularly in personnel. The priorities for the given period will be the medical exposure of patients, the radiation levels and the effects of energy production, the exposure to natural radiation sources and the improvement of the understanding of the effects of the low doses radiation exposure. (N.C.)
This paper tests the Environmental Kuznets Curve hypothesis for four local (SOx, NOx, CO, VOC) and two global (CO2, GHG) air pollutants. Using a new panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not hold for all gases. A meaningful Environmental Kuznets Curve exists only for CO, VOC and NOx, where for CO2 the curve is monotonically increasing. For GHG there is indication of an inverted U-shaped relationship between income and pollution, but still most countries are on the increasing path of the curve and hence the future development of the curve is uncertain. For SOx it was found that emissions follow an U-shaped curve. Based on the empirical results, the paper concludes that the Environmental Kuznets Curve does not hold for all gases, it is rather an empirical artefact than a regularity.
This paper tests the Environmental Kuznets Curve hypothesis for four local (SOx, NOx, CO, VOC) and two global (CO2, GHG) air pollutants. Using a new panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not hold for all gases. A meaningful Environmental Kuznets Curve exists only for CO, VOC and NOx, where for CO2 the curve is monotonically increasing. For GHG there is indication of an inverted U-shaped relationship between income and pollution, but still most countries are on the increasing path of the curve and hence the future development of the curve is uncertain. For SOx it was found that emissions follow an U-shaped curve. Based on the empirical results, the paper concludes that the Environmental Kuznets Curve does not hold for all gases, it is rather an empirical artefact than a regularity.
Sur l'origine des chiffres arabes A. Boucenna 1 From the pagination of an Algerian Arabic manuscript of the beginning of the 19th century,we rediscover the original shape that the Arabic numerals had before passing in Europe and underwent the transformation that gave the modern Arabic numerals. This original shape,whose use disappeared completely, proves that these numerals have their origin in the Arabic letters. Contrary to what some hypotheses pretend, particularly those that present them as drifting of Indian characters, the 10 Arabic numerals that we use are, nothing else, 10 Arabic letters more or less modified and taken in the "Abjadi" order. The hypothesis of the Indian origin of the Arabic numerals is revealed a mistake denied by the shape of the Arabic numerals and by the logic of the right to left representation of the numbers and the algorithm of the elementary operations. The Arabic numerals that simplified the ...
The detection of explosives is a notoriously difficult problem, especially at stand-off distances, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring optimal dynamic detection to exploit the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity of explosives signatures while reducing the influence of noise and the signals from background interferents in the field (increase selectivity). These goals are being addressed by operating in an optimal nonlinear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe ...
Thin films of Ni and Ni alloy have been widely used in microelectromechanical systems (MEMS) and magnetic storage systems. As the dimensions of components in these systems decrease to the micro-scale, even the nano-scale, the interfacial phenomena significantly differ to the counterparts on the macro-scale. A better understanding of micro-/nano-tribology will benefit the fabrication of the small components. In this manuscript parallel molecular dynamics (MD) simulations have been conducted to investigate the nanoscratch behavior of nickel. The simulations are performed for two cases with different indenter shapes. Case I has a sharp indenter, while the indenter in Case II is blunt. It has been found that the indenter shape significantly influences the nanoscratch deformation. The sharp ind...
Ni-free shape memory alloys are promising functional materials for medical applications. A newly developed Ti-Mo based shape memory alloy shows superelasticity after thermomechanical treatment. However, the microstructure evolution and precipitation during thermomechanical processes are still not well understood. In the present paper, compressive deformation behavior at a series of temperatures of 298K - 973K and tensile deformation behavior of the alloy after aged at 573K - 973K have been investigated systematically. It is found that the compressive yield stress and ultimate compressive strength change with the deformation temperature. The ultimate tensile strength and yield stress of aged specimens also change with the aging temperature following a non-linear relationship. Microstructures of aged specimens as well as effects of lattice softening and aging-induced precipitates on the deformation behavior have been investigated and discussed.
Shaped charges were first used more than 30 years ago to perforate casing, cement sheath and reservoir to provide selective communication between the reservoir and well bore. Since then, advances have been made in design of shaped charge sand ancillary equipment. Penetration has increased considerably. Miniaturization of equipment allows passing through relatively small restrictions and effectively communicating with reservoirs. Gun debris has been drastically reduced and in some designs eliminated. Deep reservoirs can be effectively penetrated under down-hole environments exceeding 500 F and 20,000 psi. This work covers the problems encountered and reviews successful devices employing shaped charge and explosive technology.
The talk will focus on spin-dependent competition between oblate and prolate shape minima in the potential energy landscape of "1"8"0Hf (the most neutron-rich stable isotope), mediated via the alignment of valence nucleons. Results of a prompt spectroscopic study, using deep inelastic reactions with Gammasphere and CHICO, bombarding a thin "2"3"2Th target with a "1"8"0Hf beam #approx#25% above the Coulomb barrier, will be presented. Nucleon alignments in both prolate and oblate minima will be discussed, as well as the favoring of oblate collective rotation at high spins, observed through a mixing with gamma vibrations built on the prolate shape.
We describe a method of determining the system parameters in non-eclipsing interacting binaries. We find that the extent to which an observer sees the shape of the Roche-lobe of the secondary star governs the amount of distortion of the absorption line profiles. The width and degree of asymmetry of the phase-resolved absorption line profiles show a characteristic shape, which depends primarily on the binary inclination and gravity darkening exponent. We show that, in principle, by obtaining high spectral and time resolution spectra of quiescent cataclysmic variables or low mass X-ray binaries in which the mass-losing star is visible, fitting the shape of absorption line profiles will allow one to determine not only the mass function of the binary, but also the binary inclination and hence the mass of the binary components.
Nov 8, 2010 ... Ihring Mission 11, the radiation dosimetry measurement system functioned normally and provided data on the Earth's trapped radiation belts ...
Selection of the appropriate radiation quality is an important aspect of optimisation for every clinical imaging task in radiology, since it affects both image quality and patient dose. Spreadsheet...Full Text Available
By proposing the four-dimensional, reciprocity transformations the appropriate condition for superluminal electromagnetic Cerenkov radiation is obtained by introducing the hypothesis that tachyons possess vector energy and scalar momentum.
drical Enclosures Using a Numerical Ray Tracing Technique. NASA. TM-I02527, 1990 . Buckley, H.: Radiation from the Interior of a Reflecting Cylinder. Philos. ...
...References | Radiation Protection | US EPA This page provides links to the reference material on EPA's Radiation Protection Web site. U.S. EPA/...OAR/ORIA/Radiation Protection Division Jump to main content. Radiation Protection Contact Us Search: All EPA This Area You are here: EPA Home ... Radiation Protection References PageName Technical Users General Public Reporters Librarians Students/Teachers PROGRAMS TOPICS REFERENCES References The Reference Section provides general material that support the ...other sections of EPA's Radiation Protection Web site. You will find links within the information to related pages throughout the Radiation Protection , EPA ...
The fundamental product of tetracycline hydrochlorine gamma radiolysis was separated in its solid state. From the results of spectroscopic studies it has been established that it is des-N,N-dimethylaminotetracycline.
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-{epsilon} model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to ...
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-? model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the ...
... iFfficiency-en- enhanced spontaneous radiation at the free-electron- ... as enhanced spontaneous radiation at the free-electron-laser wavelength. ...
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 summarize the ...
When energetic bunches of electrons traverse an undulator field, they can spontaneously emit radiation both coherently and incoherently. Although it has generally been assumed that undulator radiation is incoherent at wavelengths short compared to the longitudinal size of the electron bunch, several recent observations have proved this assumption false. Furthermore, the appearance of coherent radiation is often accompanied by a significant increase in radiated power. Here we report observations of strongly enhanced coherent spontaneous radiation together with direct measurements, using transition radiation techniques, of the electron distributions responsible for the coherent emission. We also report demonstrated enhancements in the predicted spontaneous radiated power by as much as 6x10"4 using electron bunch compression. copyright 1996 ...
... Except for isolated radiation accidents over the ensuing years, little practical experience has been gained in the treatment of thermal injuries ...
... spontaneous radiation of amplifiers within a relatively w~de range of ... pulse widths are 20-30ns, while amplified spontaneous radiation pulse ...
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The loss of lead in various kinds of biological materials after drying and ashing is studied by using "2"0"3Pb as tracer which is intravenously injected into mice. The experimental results show that although the oven ashing can be used for determining the lead in samples of lung, kidney, and liver, etc., the oxygen plasma and high pressure digestion are the most suitable methods for the determination of lead in biological materials. (author) 5 refs.; 2 tabs.
The interpretation of solution hydrodynamic data in terms of macromolecular structural parameters is not a straightforward task. Over the years, several approaches have been developed to cope...Full Text Available
The synthesis of a new kind of magnetic, fluorescent multifunctional nanoparticles (~30 nm in diameter) was demonstrated, where multiple fluorescent CdTe quantum dots (QDs) are covalently linked...Full Text Available
Pitting corrosion is a kind of electrolytic corrosion by which the surface of a material is locally affected owing to inhomogeneities on the part of the material or medium. The paper deals briefly with questions relating to the importance, to parameters medium or materialwise, influence on production and construction, as well as the general conditions for pitting corrosion. In particular oxygen corrosion in unalloyed and low-alloy steel, and pitting corrosion in ferritic chromium-steel and austenitic chromium-nickel (molybdenum) steel is described. (DG).
In clause it is shown a method optimization of brake of forces in view of a bias road it is established, that in mountain conditions of loss of coupling weight of automobiles than 2-3 times concerning flat conditions therma are more. The degree of use of coupling weight in result use of a regulator of brake forces very much increases also efficiency of brake systems such a kind of automobiles is provided with definition of optimum factor of coupling at which value of loss of coupling weight is provided minimal
For the first time a segmented n-type HPGe detector was operated directly submerged in liquid nitrogen over a long period. As this kind of detector is envisioned to be used in GERDA phase II, it was operated with a low mass signal cable with snap-contacts and mounted in a low-mass copper holder. The detector performance was stable over 146 days, indicating that neither detector nor contacts deteriorated.
A quantitative description is presented of the non-linear current-voltage response in superconducting niobium cavities for accelerator application. It is based on a fit for a large sample of data from cavity tests of different kind. Trial functions for the surface resistance describing this non-linear relation are established by a least square data fit. Those trial functions yielding the best fit are quantitatively explained by basic physics.
The transfer function concept is well known as an additional method to evaluate the impulse test of power transformers in the test laboratory. Another application for the transfer function method is monitoring of transformers in service. Thereby, Off-line and On-line monitoring can be realized. Both kinds of monitoring are demonstrated with on-site measurements on a power transformer in service.
HEW is operating one of the biggest district heating networks of the Federal Republic of Germany. The paper discusses a number of projects which in recent years have been engaged in extensive air pollution abatement measures to make district heating an environmentally compatible energy source. Emphasis is placed on the hot gas cleanup system of block 2 of the harbor power plant. The system is the first of its kind to have realized an SCR system connected with the desulfurization system for industrial denitrification purposes.
An Ottawa-based company, ECS-Power Systems Inc., has successfully completed a series of tests on an innovative device called a hydrodynamic port (HDP), which makes it possible to automatically initiate and maintain emergency cooling of a nuclear reactor core by natural processes, without relying in any way on human intervention, instrumentation, electric power, valves or moving parts of any kind.
Stylized numerical models of the tooth are usually employed in qualification procedure related to Electronic Paramagnetic Resonance in long-term accidental contamination dose reconstruction. In this work a voxel model was developed from the microCT image data set of a human non contaminated molar tooth. A stylized model, reproducing the characteristics of the voxel model, was also created in order to investigate the level of accuracy that can be obtained in this kind of study.
This report describes our initial attempts at the molecular characterization of a maize controlling element. We have prepared a cDNA probe and used it to detect changes at a locus where Ds elements are found. Evidence of their presence are indicated by changes in the restriction patterns, but there is as yet no information on the physical nature of the controlling elements nor on the kinds of rearrangements they cause.
A method of auxiliary spectrum is modified so that matrix elements of the reaction matrix in final nuclei are determined by means of algebraic operations alone (inversion of matrices). No differential equations need to be solved; Pauli's exclusion principle is accurately taken into account. A single-particle potential may be of any kind, but a two-particle interaction must have no solid core.
In a theory where the local observables are determined by local field algebras as the fixed points under a (a priori noncommutative) group of gauge transformations of the first kind, we show that, if the field algebras possess intermediate type I factors, we can construct observables having the meaning of local charge measurements, and local current algebras in the field algebras.
The etching method developed made it possible to observe under the microscope the finest components of the anatomical structure of coal-forming plants. The dependence of the effectiveness of etching of tissues on the concentrations of geopolymers (protocellulose and protolignin) in them was found. The study of tissues of this kind by the methods of local analysis (for example, X-ray microanalysis) allowed us to obtain the characteristics of the above geopolymers and to use them for the identification of the primary biochemical composition of fossil organic matter.
The Flux Mapping System (FMS) of 540 MWe PHWR is a system, which is first of its kind used in Indian PHWRs. It is used to compute a detailed flux/power distribution of the reactor core using modal synthesis method .The paper brings out the high availability features of FMS and the software design philosophy. The paper emphasizes on framework based reusable architectural design, which simplifies and speeds up the development of data acquisition systems. (author)
The paper considered the vibration signals of rotating equipment as cyclo stationary signals through analyzing the features of this kind of signals. Based on the analytic method of cyclic spectrum density, the paper pointed out that the impact frequency could be extracted effectively with the help of scanning cyclic frequency domain. The validity of the method of cyclic spectrum density is proved by simulating signals and the method is applied to the diagnosis of rolling bearings. (authors)
This paper shows the characteristics of the fertilizer production park of the State of Minas Gerais, Brazil, mainly in the aspects of energy consumption and energy sources used in the production process of the various kinds of fertilizers and by-products. A scenario including the fertilizer production evolution was made, relating this future production with the future energy consumption of this sector. 7 figs., 2 tabs.
The electroweak-symmetry-breaking sector of the standard model can be weakly-coupled or can be strongly-coupled, which is characterized by some kinds of strong interaction among the Goldstone bosons of the electroweak-symmetry-breaking sector. In this paper, we summarize an investigation of probing the strong electroweak-symmetry-breaking effects at photon colliders. ((orig.)).
The electroweak-symmetry-breaking sector of the standard model can be weakly-coupled or can be strongly-coupled, which is characterized by some kinds of strong interaction among the Goldstone bosons of the electroweak-symmetry-breaking sector. In this paper, we summarize an investigation of probing the strong electroweak-symmetry-breaking effects at photon colliders. ((orig.)).
The vibration behavior of turbomachine bladings is described, and the behavior of different kinds of coupled low pressure stages was experimentally investigated. Besides purely stationary flow conditions, conditions were also considered where pulsating fl...
The Centre d'Etudes Nucleaires de Grenoble (France) has constructed nine Vertical Axis Wind Turbines (VAWT), of Darrieus type, 5 m diameter (D5), in order to acquire a wide knowledge of this kind of wind turbines and of its performances, the final goal be...
A preliminary study of two different kinds of solar receivers (a rotating cavity receiver and a volumetric receiver) suitable to operate in the 1 kW solar facility at the University of Rome is presented. Possible applications of solar energy in the aluminum extraction from leucite and chemical storage by the CuO/Cu[sub 2]O cycle are presented and discussed. (author).
In this activity, students will make a turbidity current. They will discover how fluids of differing densities interact with one another, learn some ways the densities of fluids can be changed and observe how density currents transport and deposit tremendous amounts of sediment in lakes and in the ocean. Additional options allow students to create and observe different kinds of density currents.
Extending the usual endpoint and midpoint interactions, we introduce numerous kinds of interactions, labelled by a parameter lambda and obtain a non-commutative and associative string field algebra by adding up all interactions. With this algebra we develop a covariant open bosonic string field theory, which reduces to Witten's open bosonic string field theory under a special string length choice.
An overview is given of techniques to analyze all kinds of complaints from occupants of office buildings about their working environment: headaches, lethargy, eye irritation, respiratory problems, and complaints about the temperature and draught. Special attention is paid to the sensory evaluation of air quality. 4 figs., 7 refs.
A new method named 'Bragg curve spectroscopy', based on the Bragg curve of the heavy ion being stopped in a gaseous ionization chamber, has been developed for identifying the particle and measuring its energy. The design of such a chamber and the experience obtained with chamber using various kinds of fast heavy ions are described. In conclusion, several problems to be solved in this method are pointed out.
A new method named 'Bragg curve spectroscopy', based on the Bragg curve of the heavy ion being stopped in a gaseous ionization chamber, has been developed for identifying the particle and measuring its energy. The design of such a chamber and the experience obtained with chamber using various kinds of fast heavy ions are described. In conclusion, several problems to be solved in this method are pointed out. (orig.).
In this book an attempt has been made to describe the most recent information, but at the same time set out the fundamentals of cable technology in some depth. A focus is directed on general features of various kinds of cables. This book is written for cable engineers, and those interested in cable research, the book will also be useful to university students and management personnel interested in electric power engineering. This volume contains chapters on Present Cables and Their Improvement and New Types of Cables. (CS)
Leveraging the potential power of even small handheld devices able to communicate wirelessly requires dedicated support. In particular, collaborative applications need sophisticated assistance in terms of querying and exchanging different kinds of data. Using a concrete example from the domain of mobile learning, the general need for information dissemination is motivated. Subsequently, and driven by infrastructural conditions, realization strategies of an appropriate middleware service are discussed.
We propose an extension of Gaussian mixture models in the statistical-mechanical point of view. The conventional Gaussian mixture models are formulated to divide all points in given data to some kinds of classes. We introduce some quantum states constructed by superposing conventional classes in linear combinations. Our extension can provide a new algorithm in classifications of data by means of linear response formulas in the statistical mechanics.
... s the matter with Kansas?Legislative debates over stem cell research in Kansas and MassachusettsBonnie StabileSchool of Public Policy, ... examines the contextual factors shaping legislative debates affec...
Auditory neurons in the superior colliculus (SC) respond preferentially to sounds from restricted directions to form a map of auditory space. The development of this representation is shaped...Full Text Available
BackgroundWhile the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints....Full Text Available
BackgroundEpidemiological studies have shown a J- or U-shaped relation between alcohol and type 2 diabetes and coronary heart disease (CHD). The underlying mechanisms are not clear....Full Text Available
BackgroundThe variety of ways in which faces are categorized makes face recognition challenging for both synthetic and biological vision systems. Here we focus on two face processing...Full Text Available
Summary of recent advances (abstract)Nucleic acid-based nanotechnology has always been perceived as novel, but has begun to move from theoretical demonstrations to practical applications....Full Text Available
• Background and Aims Development and architecture of plant roots are regulated by phytohormones. Cytokinin (CK), synthesized in the root cap, promotes cytokinesis, vascular...Full Text Available
The classic evolutionary theory of aging explains why mortality rises with age: as individuals grow older, less lifetime fertility remains, so continued survival contributes less to reproductive fitness....Full Text Available
The flow of water through a dam of fairly arbitrary shape is examined in the limit of large frictional drag on the flow. The relation of the problem to the one-phase Stefan problem and a problem of anodic smoothing is explored. Monotonicity and uniqueness...
This report discusses: shape coexistence in {sup 184}Pt; nuclear structure of {sup 187}Ir; g-factors of excited states; OLNO-2; and refrigerator development.
'Trojan horses', 'logic bombs', 'armoured viruses' and 'cryptovirology' are terms recalling war gears. In fact, concepts of attack and defence drive the world of computer virology, which looks like a war universe in an information society. This war has several shapes, from invasions of a network by worms, to military and industrial espionage ...
Monodisperse noble metal nanoparticles are of tremendous interest for numerous applications, such as surface-enhanced Raman spectroscopy, catalysis or biosensing. However, preparation of monodisperse metal nanoparticles is still a challenging task, because typical preparation methods yield nanoparticle ensembles with broad shape and/or size distributions. To overcome this drawback, tailoring of metal nanoparticles with laser light has been developed, which is based on the pronounced shape- and size-dependent optical properties of metal nanoparticles. I will demonstrate that nanoparticle tailoring with ns-pulsed laser light is a suitable method to prepare nanoparticle ensembles with a narrow shape and/or size distribution. While irradiation with ns-pulsed laser light during nanoparticle growth permits a precise shape tailoring, post-grown irradiation allows a size tailoring. For example, the initial ...
A reactor was proposed in which the breeder mantel would consist of a charge of homogeneous cast breeder elements, so that the breeder element has the same shape as the fuel elements. By this method it would be possible to use the breeder element after its irradiation immediately for the charging of the fuel elements.
BackgroundRecent advances in the understanding of the maternal and paternal heritage of south and southwest Asian populations have highlighted their role in the colonization of Eurasia...Full Text Available
A feasibility study to determine what materials and geometric systems would be required for fabrication of a camouflage system that would instantaneously cover a military vehicle in order to disrupt its characteristic shape or outline. The program involve...
The cosmic ray neutron spectrum at sea level has been measured by the method of pulse shape discrimination in anthracene scintillator. The exponent of the differential spectrum was found to be 2.2+-0.1. (Auth.).
Sensory experience plays a crucial role in regulating neuronal shape and in developing synaptic contacts during brain formation. These features are required for a neuron to receive, integrate, and transmit...Full Text Available
One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present...Full Text Available
The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)
retrieve detailed aerosol and cloud particle size distribution and shape ...... but on rain types, and hydrometeor characteristics. ..... of ice streams, decreasing sea ice cover in the Arctic, poleward movement of forest cover, and ...
The binding of amphiphilic molecules to lipid bilayers is followed by 19F NMR using chemical shift and line shape differences between the solution and membrane-tethered states of...Full Text Available
A cartridge case is made by making up an aqueous slurry of cellulosic fibers, forming the fibers into a mat and molding the mat or preform into final shape by use of a die at up to 165 degrees F.
BackgroundVascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either...Full Text Available
SummaryThe evolutionary pressures that shaped the specificity and catalytic efficiency of enzymes can only be speculated. While directed evolution experiments show that new functions...Full Text Available
The cell is modeled as an ellipsoid with shell and the surface stress distribution calculated by means of the Maxwell Stress Tensor. The cell membrane is treated as incompressible material having both bending and shear energies of deformation. Employing the principle of virtual work, cell volume (and hence shape) is computed as a function of the external field strength and orientation with respect to the field. The following results were obtained: (1) The surface stresses that develop or the cell membrane are distributed having both normal and tangential components that act together to produce a rounding of the cell. (2) If the tangential component of the stress is ignored, then higher field strengths are needed to produce similar deformation (shape change) of cells. (3) The threshold value of the applied field, i.e, the field strength at which the volume (shape) of the cell changes abruptly, occurs at approximately 55V/cm. ...
The sirtuin Sirt6 is a NAD-dependent histone deacetylase that is implicated in gene regulation and lifespan control. Sirt6 can interact with the stress-responsive transcription factor NF-κB...Full Text Available
A Langmuir film is a molecularly thin film on the surface of a fluid; we study the evolution of a Langmuir film with two co-existing fluid phases driven by an inter-phase line tension and damped by the viscous drag of the underlying subfluid. Experimentally, we study an 8CB Langmuir film via digitally-imaged Brewster Angle Microscopy (BAM) in a four-roll mill setup which applies a transient strain and images the response. When a compact domain is stretched by the imposed strain, it first assumes a bola shape with two tear-drop shaped reservoirs connected by a thin tether which then slowly relaxes to a circular domain which minimizes the interfacial energy of the system. We process the digital images of the experiment to extract the domain shapes. We then use one of these shapes as an initial condition for the numerical solution of a boundary-integral model of the underlying hydrodynamics and compare the ...
Relativistic electron beams are used for generating high power microwaves. These microwave sources require electron beam generators spanning significant ranges in voltage and impedance. The pulsed power technology used to generate these electron beams is presented. Electron beam generators that produce beams with pulse durations in the 10 ns to 100 ns regime consist of an energy storage section, pulse shaping section, and an electron beam diode. The energy storage section is either a Marx generator or capacitor bank-pulsed transformer. The pulse shaping is done with high-voltage transmission lines. The electron beam diode is usually a cold-cathode, space-charge-limited flow device. For longer pulses (approx.1 ..mu..s) the energy storage and pulse shaping can be combined. Lumped-element pulsed-forming networks (PFN) can be designed to produce the desired pulse shape. The Marx generator becomes one of the ...
An unexpectedly high probability of collisions between the fission particles and the atoms in an ionization chamber along the entire particle track causes a strong fluctuation of the shapes of the Bragg curves. This fluctuation imposes an upper limit of the charge resolution ..delta..Z/Z which can be achieved.
The 3-D spectral-domain optical coherence tomography (SD-OCT) images of the retina often do not reflect the true shape of the retina and are distorted differently along the x and y...Full Text Available
A pneumatic device is in the form of a U-shaped frame, on which a prong is attached by using two pairs of levers. It also has a hydraulic or pneumatic cyclinder, whose rod is connected to one of the pairs of levers. All connections are hinges.
The lift and drag characteristics of a wide range of bluff body shapes were studied using data from sources including wind tunnel testing and flow visualization. For a given orientation of any body, it is found that its drag is strongly influenced by its ...
Gas-fired combined cycle plant may be the norm when it comes to new plant but it comes in a variety of shapes and sizes. Samarinda uses aero-derivatives with the famous Rolls-Royce RB211 gas generator. (author)
A univibrator and a pulse height discriminator using tunnel diodes and backward diodes are described, along with their applications in pulse shaping and fast coincidence technique. The main advantages achieved are simplicity of design and speed. The characteristics of the two diodes are shown. (auth)
A simple formulation is presented for torsion analysis of hollow tubes with polygonal shapes. Thicknesses of segments of cross section can be different. Governing equations in term of Prandtl's stress function are used to derive the formulas. The derived formulas are so simple that computations can be carried out with a pocket calculator. Several examples are presented to show the accuracy and efficiency of the formulation. The obtained results are verified by accurate finite element solutions. It will be seen that the derived formulas can be useful for analysis of thin-walled and moderately thick-walled hollow tubes.
A flexible, steerable tube (distal end) of an endoscope for the application in the laparoscopic surgery has been analyzed by means of the finite-element-method (FEM). The unusual mechanical and thermal features of the used shape memory alloy (SMA) of NiTi were taken in account. The analyses showed that the strains remain in the super-elastic region up to the maximum bending of 90 and no plastic deformations occur. The application of the shape optimization (CAO) made possible finding the optimal structure of the distal end and therefore powerful reducing the maximum strains in the critical regions. (orig.)
HgTe rod-shape composed of crystalline particles has been prepared by a hydrothermal method, and characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transition electron microscopy (TEM). The effects of capping agents, reductants, reaction temperatures, and reaction times on crystal structures and shapes of HgTe have been investigated. The results showed that the CTAB as capping agent plays a crucial role in the hydrothermal process. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods.
A new magnetic macroparticle filter design consisting of two 90{sup o} filters forming an S-shape is described. Transport properties of this S-filter are investigated using Langmuir and deposition probes. It is shown that filter efficiency is product of the efficiencies of two 90{sup o} filters and the deposition rate is still acceptably high to perform thin film deposition. Films of amorphous hard carbon have been deposited using a 90{sup o} filter and the S-filter, and macroparticle content of the films are compared.
A manipulator for checking the inside of a vertical, flange-shaped collector of a horizontal steam generator consists of a rotating mast with bearings at the top and bottom ends with a support that can be moved along the length of the mast for the checking system mountings. The support is propelled by a drive spindle placed parallel to the mast with its drive head bearing in the support and locked into a toothed rack attached to the mast. The checking system mountings are fitted in or on the walls of the support and are very close to the box-shaped support. Their retractable arms are hinged.
Aluminium-lithium extrusions possess high inhomogeneity of properties across the cross section. Mechanical properties such as R{sub p0,2}, R{sub m} and hardness, but also fatigue properties, change their value in dependence with the cross section position where test specimens were taken. Positions, where extreme values of properties are measured, are characteristic for a given extrusion shape. The positions with different properties have different structure and texture. Properties and structure inhomogeneity is affected mainly by extrusion shape and heat treatment parameters. (orig.)
We present ab-initio calculations of the electronic structure of small Fe clusters (1-9 atoms) on Ni(001), Ni(111), Cu(001) and Cu(111) surfaces. Our focus is on the spin moments and their dependence on cluster size and shape. We derive a simple quantitative rule that relates the moment of each Fe atom linearly to its coordination number. Thus, for an arbitrary Fe cluster the spin moment of the cluster and of the individual Fe atoms can be readily found if the positions of the atoms are known. (orig.)
Unsteady impinging jets are systematically controlled with respect to their time dependence in order to investigate the influence of unsteadiness on the heat transfer performance. This is achieved by a special mass flow control device, which allows almost arbitrary shapes of unsteadiness to be imposed onto the impinging jet. Three different standard signals (sinusoidal, triangular, rectangular) and two specially designed signals are applied and their influence on heat transfer is determined in terms of an enhancement factor. Heat transfer augmentation up to 30% was found and could be physically explained with the help of PIV and hot-wire measurements of the flow field.
The following topics are discussed: insertion of incorrect bases in DNA; ability of DNA polymerase to copy uv-irradiated DNA; role of enzymes in repair of DNA; effects of uv radiation on molecular weight of DNA; photoreactivation; repair of DNA in Escherichia coli and xp cells following uv radiation; and synchrotron radiation studies on DNA repair. (HLW)
The book is divided into two approximately equal parts. The first four chapters are relatively lengthy and cover the basic principles of radiation biology, carcinogenesis and therapy, along with a brief introduction to radiological physics to orient the reader without background in this specialized related discipline. The remainder consists of twenty-four relatively brief chapters, each covering the radiation biology of a specific organ, tissue, or systems tissues, with emphasis on the tumorigenic and tumoricidal action of ionizing radiations.
The present state of knowledge on the influence of stray radiation on image quality and its physical description and quantification is summarized. Experimental results on the influence of physical parameters on the fraction of scattered radiation and the effect of scatter reduction by air gap technique and secondary radiation grids are committed. Open theoretical and practical problems and the limitations of common methods of scatter reduction are pointed out. (author).
Disclosed herein is a radiation detector providing for the in situ automatic sampling of fluids containing substances emitting radiation, especially Cerenkov radiation. The detector permits sampling within well casings and is self-purging such that no additional provisions must be established for the storage and disposal of contaminated fluids.
A study is made of the mechanical properties of vanadium irradiated with fast neutrons up to dose 8.6.10"-"4 dpa, as a function of the temperature of post-radiation annealing. The radiation-annealing hardening (RAH) effect is observed at 300"oC, in agreement with previous studies. It is established for the first time that RAH is accompanied by fall in ductility. A phenomenological model is described which explains the dependence of RAH on radiation dose and temperature, as well as on the content of chemically active alloying impurities. (author).
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A formula is obtained which describes the kinetics of low-temperature radiation hardening caused by creation of dislocation loops of interstitial type during irradiation. The radiation hardening of aluminum and vanadium is estimated using this formula and results of experiments on studying processes of nucleation and growth of interstitial dislocation loops in these materials by transparent electron microscopy. It is shown that the proposed formula is valid for description of the kinetics of low-temperature radiation hardening.
In scattering of channeled particles by point defects and in emission of gamma rays in the spontaneous-radiation spectral region conditions are attained where the momentum transferred to the defect is taken up by the crystal as a whole. This leads to coherent and interference effects in the radiation from the crystal defects. When the longitudinal momentum transferred is zero, an induced radiation effect appears in the transitions between the states of transverse motion.
External radiation dose exceeded 5,000 rad in three cases, and intravaginal radiation dose was 5,000 rad in one case. Radiation damage including perforation was seen in the end of ileus in one case, in the sigmoid and rectum in two cases, and in the end of ileus, sigmoid and rectum in the last case. Satisfactory results were obtained by the removal of the ileocecum in the case of the damage in the end of the ileus. However, only colostomy was performed for the damage in the sigmoid and rectum.
Due to the intensity and vast number of subjects, this Bremen experts' discussion, too, could discuss only part of the problem of the possibilitiy to quantify the radiation hazard. One preliminary result is that there is no scientific proof of the harmlessness of radiation exposure during normal operation of a nuclear power plant, either within the plant or in its vicinity. Other results are that some important questions can not be answered yet, and that there are important hints on the dangers even of low radiation doses. (GL).
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of {sup 6}Li and {sup 7}Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of {sup 6}Li and {sup 7}Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of "6Li and "7Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of "6Li and "7Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
The total radiation rate, angular distribution of the emitted energy and photon correlations of the cooperative spontaneous radiation from two atoms with different resonance frequencies and spontaneous decay rates are calculated. Contrary to the case of two identical atoms oscillations appear in the total radiation rate and the spatial distribution of the total number of emitted photons differs from the single-atom radiation pattern. The effect of the dipole-dipole near-field interaction on the time evolution of the atomic system is discussed. (author).
BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available
Results on defect structure study and degree of molybdenum radiation hardening irradiated by fission neutrons and medium energy alpha-particles are presented. It is shown that molybdenum irradiation by alpha-particles and neutrons leads to different degree of material hardening for the same damage level. It is established that molybdenum radiation hardening is mainly defined by radiation defect clusters visible in electron microscope whose coefficient of rigidity depends on their size. 5 refs.; 6 figs.; 2 tabs. (author).
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 electron beam diagnostics. We discuss Coherent Edge ...
The influence of a periodic electromagnetic field on the radiative corrections to the atomic energy levels is studied for the case of ''strong fields'' for which the interaction between the atom and field is of the order or greater than the radiative effects. The analysis is carried out on the basis of the Schwinger-Dirac equation for the propagation function of a bound electron in the field and on the basis of the density matrix in the Furry representation. It is shown that in the strong field approximation the radiative shifts and widths are manifest as radiative corrections to the quasi-energies. In super-high resolution experiments intensity effects in the radiative corrections to the atomic levels are obtained in the case of single-photon resonance. Some multiphoton processes are condidered by taking into account the effect of the field on ...
The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and ...
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. ...
Purpose: The determination of tumor volume in ocular tumors is very important for the planning and success of radiation therapy. This study uses an animal model to evaluate the accuracy of MR-based volumetry of ocular tumors. Materials and methods: In a total of 25 porcine eyes obtained from the slaughterhouse, ocular tumors were produced by injecting a mixture of hand creme and Gd-DTPA under ophthalmoscopic guidance. The injected volume varied between 0.05 ml and 2.7 ml. The eyes were examined with a 1.5 Tesla scanner and a 4 cm circular surface coil especially developed for ocular MRI. After data transfer to a separate workstation, volumetric analysis was carried out by three independent radiologists using semiautomated software. The determined volume was compared with the injected volume. Results: Of the 25 prepared porcine eyes, 23 were suitable for volumetric analysis. The injection of the mixture of hand creme and GD-DTPA produced two different types of ...
The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been ...
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation. (author).
Standard radiation monitoring has been conducted at Sendai nuclear power station for the purpose of estimation of 'source activity' during refueling outage and evaluation of countermeasures to reduce dose rate. Selected objects of the monitoring are radiation dose rate at maintenance area, radiation field at each equipment and piping, coolant chemistry and plant operation condition. Monitored data indicates that 'source activity' variation can be estimated to some extent using influential factors, and that evaluation of change of loose crud activity, which is presumed to be represented by the dose rate at letdown heat exchanger, is necessary to further explain change in radiation field at main work area. (author).
The authors give a survey of the somatic radiation risk in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk.
The authors give a survey of the somatic radiation ris in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk. (orig.).
The diffusion coefficient of particles in radioactive gases has been calculated with account of random wandering of aerosols (occurrence of local fields affecting the particles; recoils accompanying radiation emitted by particles, etc.). To determine the diffusion coefficient, the method of Fokker-Planck equation derivation was used. A formula is presented for calculating the radiation-stimulated diffusion coefficient. A linear growth of the diffusion coefficient with radioactivity is noted according to the formula, the diffusion coefficient is mainly determined by the field in the radiation damage region. The aerosol radioactivity may result in a more rapid deposition of aerosols in the pipelines and aerosol purification systems. The diffusion rate grows not only in the presence of intrinsic radioactivity but in case of external radiation exposure as well.
The results of theoretical and experimental investigations, describing the effect of ionizing radiation on wood and its main components and methods for production of wood-plastic composites by means of radiation-induced chemical modification are generalized. Domestic and foreign experience in their production is systematized; physico-mechanical characteristics of new material, simulation and calculation of irradiating devices, as well as calculation and experimental study of #gamma#-radiation attenuation both by wood material and by wood of different species are given. Gamma sources ("6"0Co isotope, a hot loop of a nuclear reactor) as well as electron accelerators are considered as ionizing radiation sources.
RADSOLVER is a computer program which calculates the radiation energy transport in cavity type receivers having an arbitrary number of apertures through which collimated beams of solar radiation enter. In contrast to the common assumption of gray (or semi-gray) surfaces used in the modeling of radiation transport, RADSOLVER accounts for the wavelength-dependence of emission, absorption and reflection with a band model of the radiative properties. It is intended that this report serve both as an instruction manual for the use of the RADSOLVER code and a vehicle for presenting the underlying theory. Illustrative examples along with input and output are presented.
Outage is a specific period of time for radiation protection in a nuclear power plant, in which the radiation risk and collective dose are both at the highest level. In this article, the practice and experience of occupational exposure control in the outages of Daya Bay Nuclear Power Plant are introduced through following aspects: early involvement in outage preparation by radiation protection service, control of source term, radiation protection and safety management in the outage implementation processes, the effectiveness of the plant's safety management network and overall involvement of all staffs of the plant, experience feedback and continuous improvement in radiation protection management, etc
In radiation risk assessment it must be differentiated between somatic and genetic effect on the one hand as well as between stochastic and non-stochastic effect on the other. According to definitions of the ICRP report 26 the limit for the dose equivalent of all tissues prevents non-stochastic radiation effects. With stochastic radiation effects probably exist no threshold doses; therefore the ALARA principle must be applied concerning radiation protection. The individual risk by stochastic radiation effects in its linear, linear-quadratic and quadratic extrapolations, respectively, is discussed in detail. The effective stochastic dose equivalent (H/sub eff/) as well as collective dose and collective damage are outlined.
In Korea, the Proton Engineering Frontier Project (PEFP) is building a proton linear accelerator facility with energy up to 100MeV and a beam current of 20mA. In this study, a radiation field after shutdown in the accelerator facility of the PEFP was evaluated for the purpose of the radiation shielding by using MCNPX code. A facility modeling was performed for the accelerator tunnel building, accelerator chain, target rooms and beam experiment hall. And radiation source terms were evaluated in the facility. With this facility, model and radiation source terms, the concentration of 41Ar was evaluated and the cooling time satisfying regulation in Korea was calculated.
Delayed cerebral necroses after irradiation are to be divided into hemispheric and midline lesions, as they differ from each other in several aspects. Apart from the symptoms, they are differing in the duration of latency, in the course and prognosis, and also with regard to morphology. Though there is no doubt that radiation tolerance of cerebral midline structures is relatively limited, on biological grounds, evidence of a difference between the tolerated doses could not be given from the existent inhomogeneous radiation data, with the help of the NSD-concept. Radiation planning for the region of the head, nevertheless, carefully should avoid in every case to involve the structures of the cerebral midline.
Remote-controlled handling systems are required for work to be done in the decommissioning and dismantling of nuclear facilities. These systems are equipped with electronic devices suitable for use in working environments affected by ionizing radiation. The publication explains the step-wise progress achieved for improving the radiation resistance of electronic devices with the example of a four-quadrant controlling device for the motors of a manipulator. The radiation resistance of the device could be enhanced to radiation energies of 5.500 Gy. This means that a manipulator vehicle equipped with this controlling device can take up to approx. 15 kGy all in all, taking into account its own shielding properties. (DG).
Investigations were carried out of radiation level around Daya Bay for three times since the construction and operation Daya bay Nuclear Power Station and Lingao Nuclear Power Station in Guangdong province in the period of 1988 to 2000. As shown by the investigation, the radiation levels both in the field and indoors remains unchanged by and large but slightly higher than before on the roads. Also this paper gives the analysis of variations in radiation levels form site to site and from time to time. It was shown that, for environmental ? radiation levels measurements, typical measuring sites have significant impact on the meaning results. (authors)
The work scope of 'Biological Research for the Radiation Protection' had contained the research about ornithine decarboxylase and its controlling proteins, thioredoxin, peroxiredoxin, S-adenosymethionine decarboxylase, and glutamate decarboxylase 67KD effect on the cell death triggered ionizing radiation and H_2O_2(toxic agents). In this study, to elucidate the role of these proteins in the ionizing radiation (or H_2O_2)-induced apoptotic cell death, we utilized sensesed (or antisensed) cells, which overexpress (or down-regulate) RNAs associated with these proteins biosynthesis, and investigated the effects of these genes on the cytotoxicity caused by ionizing radiation and H_2O_2(or paraquat). We also investigated whether genisteine(or thiamine) may enhance the cytotoxic efficacy of tumor cells caused by ionizing radiation (may enhance the preventing effect ...
The oxidative dehydrogenation (ODH) of light alkanes is an alternative way for the production of olefins. A wide variety of catalytic systems has been investigated. Vanadium oxide based catalysts were described in the literature as effective catalysts for the ODH of propane. The catalytic activity and selectivity depend on the kind of support material, the kind of dopants and the formation of complex metal oxide phases. In recent papers it was claimed that both orthovanadate and/or pyrovanadate species are selective for the ODH of propane. Niobia based materials were investigated as catalysts for acidic and selective oxidation type reactions. In the ODH of propane niobia exhibited a high selectivity to propene but the conversion of propane was low. V{sub 2}O{sub 5}-Nb{sub 2}O{sub 5} catalysts proved to be catalytically active and selective and showed no formation of oxygenates. In the present study the influence of the niobia dopant of the ...
Red mud is generated as a by-product in the production of Al(OH){sub 3}/Al{sub 2}O{sub 3} from bauxite ore. In this study the pellet-type adsorbents have been made from the red mud, and their adsorption capacities of heavy metal ions have been tested. The pellet-type adsorbents were synthesized to utilize the excellent adsorption capacity of the powder-type adsorbent for industrial application. The pellet-type adsorbents were prepared by mixing several kinds of additives with the red mud. It is found that the pellet-type adsorbent, made by sintering a mixture of red mud (96.0 wt%), polypropylene (2.5 wt%), fly ash (0.5 wt%), and sodium meta-silicate (1.0 wt%) at 1200 deg.C for 30 minutes, has the highest adsorption capacity. In this work, the two kinds of pellet-type adsorbents (bead-type, crushed-type) were prepared. The crushed-type adsorbent was found to show a better adsorption/desorption performance than the bead-type adsorbent. The ...
Flue gas desulfurizing capacities of active carbon fibers (ACF) made from polyacrylonitrile (PAN-ACF) were studied, the features were clarified and at the same time the factors governing the capacities were studied to get guides for better products. Desulfurization capacities of 17 kinds of ACFs were studied. Two kinds of PAN-ACF, FE-200 and FE-300, especially the latter exhibited the higher desulfurization capacity. The capacity of FE-300 was about 20 times higher than those of fibers other than PAN systems and about 4 times higher than that of active coke for desulfurization. From the influence of reacting conditions on the desulfurizating capacity and the desorption profiles of adsorbed SO {sub 2}, it was concluded that the capacity was determined by the effective adsorption capacity of ACF and SO {sub 2} was retained on ACF as sulfuric acid. It was suggested that main factors governing the adsorption capacity were the large surface area of ...
The complex ghost introduced previously by the present author is studied from a standpoint whether its effects are observable by experiments or not. According to the theory of complex ghost the scattering cross section of two real particles shows some particular properties. It has a kind of resonance peak at a certain energy which does not conform to the Breit-Wigner formula. It has also a peak for a certain energy transfer, if there exist tachyons. The tachyon is a kind of ghost and is allowed to exist in the theory. Using these properties the complex ghosts are expected to be detected by experiments. The recently observed resonance psi(3.1) is supposed to be the complex ghost of photon, since they have the same quantum numbers. If it is assumed, some properties of the resonance known by experiments are explained naturally to a certain extent. Along the same line it is not unnatural to expect that the photon is also accompanied by a tachyon as ...
A risk-neutral method is always used to price and hedge contingent claims in complete market, but another method based on utility maximization or risk minimization is wildly used in more general case. One can find all kinds of special risk measure in literature. In this paper, instead of using market modified risk measure, we use a kind of risk measure induced by g_\\Gamma-solution or the minimal solution of a Constrained Backward Stochastic Differential Equation (CBSDE) directly when constraints on wealth and portfolio process comes to our consideration. Such g_\\Gamma-solution and the risk measure generated by it is well defined on appropriate space under suitable conditions. We adopt the inf-convolution of convex risk measures to solve some optimization problem. A dynamic version risk measures defined through g_\\Gamma-solution and some similar results about optimal problem can be got in our new framework and by our new approach.
Steam Generator (SG) tubes in PWR plant are periodically inspected using eddy current testing (ECT) method. In Japan, bobbin coil type dual function probe is used for full length inspection, but the detectability for circumferential crack is very poor, and to improve detectability for circumferential crack and supplement regular ECT, various kinds of multi segment eddy current probes and multi transducer ultrasonic testing (UT) method have been developed. ECT probes are constructed of multiple surfaceriding special winding differential type coils and UT probe consists of 16 transducers which are spaced equally around the probe circumference for 360deg wall coverage. Both of those EC and UT probes are designed effective to detect circumferential crack. On the other hand, various kinds of laboratory induced circumferential cracks have been made and destroyed to prove the detectability of these probes. (author).
Geometrically anisotropic eddy current probes are a type of separate function probes especially fit to the detection of defects showing a preferential direction. This kind of flaw induces a coupling between the transmitter and the receiver by guiding eddy currents from the one to the other. On the other hand, this coupling will be almost non-existent in the presence of defects or spurious effects not displaying this geometrical particularity. Basic studies on an elementary two-coil set-up allow the acknowledgment of the intrinsic qualities of such probes: good signal-to-noise ratio, influence field practically constant on the whole defect length, ability to detect bridged defects, insensitivity to lift off. These results can be improved by achieving multicoils probes adapted to different kinds of problems. An application to continuous casting slabs testing yields very interesting results in the detection of cracks, while getting rid of the ...
Power plants generate a great amount of ash during coal combustion. From this process two different kinds of ashes are extracted: fly ash (FA) and bottom ash (BA). In this work possible use of both fly and bottom ash as raw material for the ceramic industry is analyzed. The samples were formed by mechanical mixing of both kinds of ashes, and density evolution during conformation as structural ceramic (packing, pressing and sintering) was studied. It was verified that powders with larger fly ash content exhibited higher packing density resulting in compacts with improved green and sintered densities. Preheating treatments at temperatures above 600{sup o}C also increased the green and sintered densities. Dilatometric curves on compacts formed from FA and BA powders were run at constant heating rate and at isothermal cycles. From the analysis of these data it can be established that liquid-phase sintering is the densification mechanism present at ...
In this paper, we used Ca-alginate gel beads coated with polyetheneimine and glutaraldehyde to adsorb Expansum penicillium lipase. The immobilized lipase catalyzed esterification of 1-dodecanol with dodecanoic acid in benzene. The results show that when the concentration of Ca-alginate, polyetheneimine (PEI) and glutaraldehyde is 1%, 6% and 1%, respectively, the activity of the immobilized lipase and the amount of adsorbed protein are the highest. The immobilized lipase is better than the SDS-immobilized lipase. The activity of the immobilized lipase connected by glutaraldehyde is higher than the activity of that without glutaraldehyde. The initial rate of the immobilized lipase and lyophilized lipase powder is 5.9 x 10(2) nmol/min.mgpr and 2.8 x 10(1) nmol/min.mgpr, respectively. After the immobilized lipase catalyzed the esterification reaction at 37 degrees C for about 12 hours, 93.3% of 1-dodecanol was converted to ester, but for lyophilized lipase powder, only 17.5% converted. ...