17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
We studied the mechanism of Ascophyllum nodosum (a brown macroalga) induced resistance in Arabidopsis thaliana against Pseudomonas syringae pv. tomato DC3000. Root treatment of A. thaliana Col-0 plants with extracts of A. nodosum [aqueous (ANE), chloroform (C-ANE) and ethylacetate fractions, (E-ANE)] reduced the development of disease symptoms on the leaves. These extracts also induced resistance in salicylic acid deficient NahG and ics1 plants. However, the extracts did not elicit an effect on jar1 (jasmonic acid resistance 1) mutant. A. nodosum extract induced resistance to Pst DC3000 correlated with increased expression of jasmonic acid related gene transcripts PDF1.2 while PR1 and ICS1 expression were less affected. Additionally, pretreatment of Arabidopsis plants with ANE, protected t...
Monolithic N-channel junction field effect transistors (NJFETs) dc characteristics, small signal parameters and noise have been studied from 300 K down to cryogenic temperatures before and after irradiation with {sup 60}Co {gamma}-rays and fast neutrons (1 MeV). Radiation induced effects on dc parameters and noise are reviewed. Noise spectral density measurements performed at various temperatures have shown that the radiation induces a noise increase which is temperature and frequency dependent. (orig.). 14 refs.
Hard Nano-Strutural Coatings Resistant to the Extreme Conditions of Chemical, Abrasive and High Energy Media for Thermonuclear Power, Oil and Gas and Chemical Industries
The results have been presented of DC polarization and exposure investigations of alloy steels used as construction materials in flue gas desulphurization installations. on the base of analysis of composition of investigated steels and results of polarization studies, conditions have been discussed in which the pitting resistance equivalent (PRE) should be used. Among tested steels the significantly highest resistance to pitting corrosion is exhibited by 654SMO steel, classified as the super austenitic grade. (author). 14 refs, 3 figs, 2 tabs.
Process control transmitters that incorporate digital signal processing could be used advantageously in nuclear power plants; however, because such transmitters are too sensitive to radiation, they are not used. The Electric Power Research Institute sponsored work at Sandia National Laboratories under EPRI contract RP2614-58 to determine why SMART transmitters fail when exposed to radiation and to design and demonstrate SMART transmitter circuits that could tolerate radiation. The term ''SMART'' denotes transmitters that contain digital logic. Tests showed that transmitter failure was caused by failure of the complementary metal oxide semiconductors (CMOS)-integrated circuits which are used extensively in commercial transmitters. Radiation-hardened replacements were not available for the radiation-sensitive CMOS circuits. A conceptual design showed that a ...
A wear-resistant nitrided layer was formed on a 304L austenitic stainless steel substrate by DC plasma nitriding. Effects of DC plasma nitriding parameters on the structural phases, micro-hardness and dry-sliding wear behavior of the nitrided layer were investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, micro-hardness testing and ring-on-block wear testing. The results show that the highest surface hardness over a case depth of about 10 #mu#m is obtained after nitriding at 460 deg. C. XRD indicated a single expanded austenite phase and a single CrN nitride phase were formed at 350 deg. C and 480 deg. C, respectively. In addition, the S-phase layers formed on the samples provided the best dry-sliding wear resistance under the ring-on-block contact configuration test.
Conventional methods for calculating electricity losses in pipe-type cable systems rely heavily on data measured in lower-voltage systems in the 1950s. With the new technique developed in this study, engineers can compute power losses more precisely for cables of various configurations and voltage ratings.
This discussion outlines a few areas of fundamental research which appear vital for progress in developing advanced propulsion concepts using dc railgun thrusters. We have placed emphasis on the following: (1) dense plasma and high current density influences on changes in microstructure and properties of conventional rail conductors such as Cu, Al, and W alloys or composites; (2) the influences described in (1) on more advanced high temperature, microstrain resistant, materials such as amorphous tungsten; (3) location, description and temporal evolution of current, magnetic field, and losses during intense plasma-current field interactions with conductors; and (4) composite materials and sequentially sectioned structures for more efficient EM dc launcher configuration.
Using electromatic field theory, a new method is developed for calculating alternating current in power cables installed in pipes of carbon steel (magnetic pipes). The technique for evaluating these losses is based on the method of images which replaces complicated distribution of currents in the system with a sequence of thin conductors. The method not only gives a mathematical framework for the solution of alternating current losses, but it also gives the underlying physical picture of effects contributing to these losses. Skin effect, proximity effect and losses due to the pipe are calculated separately. For the first time, the increase of losses in the conductors, when the cables are placed in a magetic pipe, are analyzed mathematically. Good agreement is obtained between the result of calculations and the experimentally determined ac-dcresistance ratios for pipe-type cables with concentric stranded copper conductors and also for cables ...
A Numerical study of beam dynamics was performed for two injector systems for the proposed National High Magnetic Field Laboratory at the Florida State University (FSU) Free Electron Laser (FEL) facility. The first considered a system consisting of a thermionic DC gun, two buncher cavities operated at 260 MHz and 1.3 GHz and two TESLA type cavities, and is very similar to the injector of the ELBE Radiation Source. The second system we studied uses a DC photogun (a copy of JLab FEL electron gun), one buncher cavity operated at 1.3 GHz and two TESLA type cavities. The study is based on PARMELA simulations and takes into account operational experience of both the JLab FEL and the Radiation Source ELBE. The simulations predict the second system will have a much smaller longitudinal emittance. For this reason the DC photo gun based injector is preferred for the proposed FSU FEL facility.
Radiation degradation of polycarbonate (PC) and polybutylene terephthalate (PBT) used as cable connector was evaluated using DSC, TGA, and mechanical properties. Glass transition temperature, melting temperature, 5% weight loss temperature, elongation at break, and tensile strength measurements were carried out for each of {gamma}-ray irradiated samples. In the results of those analyses, PC has radiationresistance better than PBT as a cable connector material.
Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)
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 radiationresistance of electronic devices with the example of a four-quadrant controlling device for the motors of a manipulator. The radiationresistance 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).
This report, entitled Combustion Engineering Standard Safety Analysis Report -- Design Certification (CESSAR-DC), has been prepared in support of the industry effort to standardize nuclear plant designs. These volumes describe the Combustion Engineering, Inc. System 80"+trademark Standard Design. This volume 11 discusses Radiation Protection, Conduct of Operations, and the Initial Test Program.
The authors have measured the noise of MOS transistors of the United Technology Microelectronics Center (UTMC) 1.2 [mu]m radiation hardened CMOS P-well process from the weak to moderate inversion region. The noise power spectral densities of both NMOS and PMOS devices were measured from 1 KHz to 50 MHz. The bandwidth was chosen such that the important components of the spectral densities such as the white thermal noise and the 1/f noise could be easily resolved and analyzed in detail. In this paper the effects of different device terminal DC biases and channel geometries on the noise are described.
Development of Portable Normobaric Hypoxia and Pulsed Magnetic Field Firmware System for Enhancement of Radio- and Non-specific Resistance in Workers of Environmentally Hazardous Industries
Rotifers of class Bdelloidea are common invertebrate animals with highly unusual characteristics, including apparently obligate asexuality, the ability to resume reproduction after desiccation at any...Full Text Available
DCresistivity, dc magnetization, and specific heat of eight Sc{sub 5}Co{sub 4}Ge{sub 10}-type crystal-structure compounds R{sub 5}T{sub 4}Ge{sub 10} for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single-crystal magnetization, and specific-heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like {theta} reflects the strength of the crystal-field torque on the magnetic moments rather than the ...
DCresistivity, dc magnetization, and specific heat of eight Sc/sub 5/Co/sub 4/Ge/sub 10/-type crystal structure compounds R/sub 5/T/sub 4/Ge/sub 10/ for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single crystal magnetization, and specific heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients ..cap alpha../sub j/, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like theta reflects the strength of the crystal field torque on the magnetic ...
We present the low-temperature physical properties of the polycrystalline perovskite systems La2/3A1/3Mn1-xCoxO3, A=Ca, Sr (0.5x1) including electrical resistance, magnetization, ac and dc susceptibilities. The experimental data suggest the presence of correlated ferromagnetic clusters embedded in some non-ferromagnetic matrix. The systems show semiconducting behavior and negative magnetoresistance.
Critical current density and dissipation of four sintered YBCO filaments were measured using a continuous DC power supply. Each sample exhibited somewhat different characteristics from the others even though 3 of the 4 samples are from the same batch. The data suggest that it is possible for the YBCO filament to be in a state of stable equilibrium when part of the filament is in the flux-flow state and part of the filament is in the normal state (local hot spots). This behavior may be advantageous for resistive fault current limiters because the intermediate state (partly flux-flow and partly normal) has an overall resistance much higher than that of the flux-flow state but it does not lead to thermal runaway (burnout) or excessive heating compared to a YBCO filament driven into normal state over its entire length. Two of the samples were broken as a result of local burnout.
A patent is claimed for the invention of a hardening (ionizing radiationresistance) process for MOS type components and CMOS or bipolar type components. The ionizing radiation effect on those systems is the electron-hole pair production, which induces interference phenomena. The MOS main structure is successively composed of a silicon substrate layer, a layer of an irradiation resistant material and a layer of partially monocrystalline silicon.
For the protection of buried steel pipeline, it is common practice to coat the pipelines with highly insulating coating and apply a cathodic current to insulate the pipe from the aggressive environment. Cathodic current protects holidays or damaged area of coating which required less current than would be needed for an uncoated pipe, but because of the cathodic reactions evolution will be taken H{sub 2} and OH{sup -} on holidays which exposed metal to the environment place. This effect is to cause loss bond of coating around the holidays called cathodic dis-bonding. In this paper we measured cathodic dis-bonding of three types of coatings at - 1.5 V(Cu/CuSO{sub 4}) according to ASTM G8. We studied on cathodic dis-bonding resistance of petroleum-base, coal tar-base and polyethylene plastic tape coatings. After 30 days immersion in electrolyte it was found that the cathodic disbanding resistance of polyethylene plastic tape coating is lower than ...
In response to a heat shock, the yeast Saccharomyces cerevisiae undergoes a large increase in its resistance to heat and, by the induction of its recombinational DNA repair capacity, a corresponding increase in resistance to radiation. Yeast which lack mitochondrial DNA, mitochondria-controlled protein synthetic apparatus, aerobic respiration, and electron transport (rho/sup 0/ strain) were used to assess the role of O/sub 2/, mitochondria, and oxidative processes controlled by mitochondria in the induction of these resistances. We have found that rho/sup 0/ yeast grown and heat shocked in either the presence or absence of O/sub 2/ are capable of developing both radiation and heat resistance. We conclude that neither the stress signal nor its cellular consequences of induced heat and radiationresistance are directly ...
Type 440C stainless steel is a high-C, high-Cr martensitic steel used in applications requiring high hardness and wear resistance in combination with moderate corrosion resistance. Typical applications include precision aerospace bearings and critical components in computer disk drives. The properties of passive films formed on 440C steel were investigated using advanced electrochemical techniques with a view to establishing a method to measure film stability directly in the passivation baths. Electrochemical measurements were sensitive to the passive film properties and were able to quantify the effect of cooling rate on passive film stability. The techniques used included linear polarization, AC impedance, small amplitude cyclic voltammetry, and coulostatic transient measurements. These provided results that exhibited excellent agreement with the AC impedance technique providing the most information about the interfacial reactions. It was ...
The resistance of six tropical hardwoods to fungal degradation by two wild-type strains of Phanerochaete chrysosporium Burdsall was investigated using vermiculite burial and wood-block weight loss techniques. Radiation-induced wood-polymer composites (WPC), based on two hardwoods Ramin and Rubberwood with methyl methacrylate, were prepared, and samples were also exposed to the wood-rotting fungus. A significant improvement in resistance to fungal decay was observed in the WPC. Scanning-electron micrographs of the two woods and their composites after fungal degradation are presented and discussed.
To test the effect of humidity on the radiationresistance of Deinococcus radiodurans, air-dried cells were irradiated with germicidal 254?nm UV, and simulated environmental UV or ?-radiation and survival was compared to cells in suspension. It was observed that desiccated cells exhibited higher levels of resistance than cells in suspension toward UV or ?-radiation as well as after 85?C heat shock. It was also shown that low relative humidity improves survival during long-term storage of desiccated D. radiodurans cells. It can be concluded that periods or environments in which cells exist in a dehydrated state are beneficial for D. radiodurans? survival exposed to various other stresses.
A familiar power inverter circuit, combined with a ferroresonant transformer and a simple control circuit, provides the basis for an economically attractive modular family of DC to DC converters. The circuit is readily adaptable to a wide range of input voltages and single or multiple output voltages.
As a part of the program at the Lawrence Livermore National Laboratory (LLNL) in induction-linac free-electron laser (IFEL) research, the authors are conducting a variety of activities addressing the unique requirements imposed on IFEL wiggler systems. They are actively developing improved DC iron-core electromagnetic wiggler designs to attain higher peak fields, greater tunability, and lower random error levels. They are pursuing specialized control systems, such as magnetic-field and beam-position controllers, which can relax requirements on the wiggler itself. They are also pursuing basic studies to establish the effect of radiation on permanent magnets.
As a part of the program at the Lawrence Livermore National Laboratory (LLNL) in induction-linac free-electron laser (IFEL) research, we are conducting a variety of activities addressing the unique requirements imposed on IFEL wiggler systems. We are actively developing improved dc iron-core electromagnetic wiggler designs to attain higher peak fields, greater tunability, and lower random error levels. We are pursuing specialized control systems, such as magnetic-field and beam-position controllers, which can relax requirements on the wiggler itself. We are also pursuing basic studies to establish the effect of radiation on permanent magnets.
The magnetically fluidized bed (MFB) was used as the reactor in a novel semidry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency. Experiments in a laboratory-scale apparatus were conducted to reveal the effects of approach to adiabatic saturation temperature, Ca/S molar ratio and applied magnetic field intensity on SO(2) removal. Results showed that SO(2) removal efficiency can be obviously enhanced by decreasing approach to adiabatic saturation temperature, increasing Ca/S molar ratio, or increasing applied magnetic field intensity. At a magnetic field intensity of 300Oe and a Ca/S molar ratio of 1.0, the desulfurization efficiency (excluding desulfurization efficiency in the fabric filter) was over 80%, while spent sorbent appeared in the form of dry powder. With the SEM, XRD and EDX research, it can be found that the increase of DC magnetic field intensity can make the surface morphology on the surface of the ferromagnetic ...
This paper presents a novel organization of switch capacitor charge pump circuits based on voltage doubler structures. Each voltage doubler takes a DC input and outputs a doubled DC voltage. By cascading voltage doublers the output voltage increases up to 2 times. A two-phase voltage doubler and a multiphase voltage doubler structures are discussed and design considerations are presented. A simulator working in the Q-V realm was used for simplified circuit level simulation. In order to evaluate the power delivered by a charge pump, a resistive load is attached to the output of the charge pump and an equivalent capacitance is evaluated. To avoid the short circuit during switching, a clock pair generator is used to achieve multi-phase non-overlapping clock pairs. This paper also identifies optimum loading conditions for different configurations of the charge pumps. The proposed charge-pump circuit is designed and simulated by ...
Chromium electroplated AISI 316L stainless steel was nitrided using inductively coupled plasma (ICP) for application in the bipolar plate of a polymer electrolyte membrane fuel cell (PEMFC). A continuous and thin chromium nitride layer was formed at the surface of the samples after ICP nitriding for 2 h at 400 C. The interfacial contact resistance (ICR) and corrosion resistance in simulated PEMFC operating conditions were higher than the required values, while they varied with the applied dc bias voltage during the nitriding process. The ICR value decreased with an increase in bias voltage. Potentiodynamic polarization measurements showed that all of the nitrided samples had excellent corrosion resistance with a current density of {proportional_to}10{sup -7} A cm{sup -2} at the cathode. It was also found that the oxygen content at the surface was not increased after the corrosion test. X-ray ...
This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the head. It is emphasised ...
Nuclear battery produces electricity by converting radiation energy into electrical energy. Energy carried by particles emitted by a radioisotope nuclei is much higher than that released in chemical reaction. Reaction with nuclei can potentially produce electricity thousand to million times higher than that of chemical reaction. Unlike NPP that produces large scale alternating current using thermodynamic cycle such as Rankine or Brayton cycles, nuclear battery is designed like other battery or fuel cell, to produce direct current (DC). However, both battery utilize the energy or particles radiating from nuclei of a radioisotope. In this paper, several types of nuclear battery as an energy converter are discussed, including their working mechanisms and examples. Nuclear battery is potential to become a long-life power source for use in wide range of applications, including in medical areas and for instruments in remote areas ...
Various nylons including nylon 6, nylon 66, nylon 610 and nylon 12 in the forms of fiber and film were irradiated with the gamma-ray from Co-60 at the dose rate of 0.12 Mrad/hr in the atmosphere of oxygen at 7 kg/cm/sup 2/ and at the room temperature. The irradiation in vacuum on the same specimens was performed at 0.5 Mrad/hr. The tensile properties and the gel fraction of the irradiated nylon samples were measured, and the radiationresistance of the nylons against the irradiation at low dose rate was estimated. From the experimental results, it became clear that in the case of irradiation in vacuum, all the nylons were durable to the irradiation of 250 Mrad or more, and nylon 6 was more durable than nylon 12, and in the case of irradiation in pressurized oxygen, the radiationresistance of the nylons decreased to one-tenth as compared with that in vacuum, and contrary to that in vacuum, nylon 12 was ...
In future experiments the readout electronics for pixel detectors is required to be resistant to a very high radiation level. In this paper we report on irradiation tests performed on several preFPIX2 prototype pixel readout chips for the BTeV experiment exposed to a 200 MeV proton beam. The prototype chips have been implemented in commercial 0.25 {micro}m CMOS processes following radiation tolerant design rules. The results show that this ASIC design tolerates a large total radiation dose, and that radiation induced Single Event Effects occur at a manageable level.
The behaviour of the packaging materials under radiation field has a great importance in radiation processing, because, in most cases, they are finally responsible for the preservation of the beneficent changes achieved in irradiated products. For example, in radiation sterilisation and food irradiation, the packages must preserve the sterilisation, respectively the sanitisation. They must preserve also the physical barrier feature. The radiation effects on plastics were extensively studied in the last decades for nuclear industry and more recently for radiation processing. The two major effects of nuclear radiation on polymeric materials are the degradation and cross-linking. The degradation consists in breaking of macromolecules after interaction with nuclear particles, amplified by the free radicals which persist long periods, especially in crystalline ...
Samples of fat coal-E, its roof sandstone-A and blind coal-W from two coal mines in Hebei Province of China were brought to the laboratory to study the features of infrared thermal images and radiation temperature in the course of uni-axial load and uni-axial cycle load. To check the results of infrared remote sensing detection, two other methods, acoustic emission detection and electrical resistance detection were also used. The AGA-782 thermalvision detected change of the temperature field of the samples` surfaces. The study showed that: (1) coal rocks and sandstone in the course of loading have three types of infrared thermal image features and three types of infrared radiation temperature features; (2) infrared detection is comparable with acoustic emission detection and electrical resistance detection. Generally, the infrared forewarning of coal rocks` failure comes later than that of acoustic and ...
ITN Energy Systems is developing next-generation solar cells based on the concepts of an optical rectenna. ITN's optical rectenna consists of two key elements: (1) an optical antenna to efficiently absorb the incident solar radiation, and (2) a high-frequency metal-insulator-metal (MIM) tunneling diode that rectifies the AC field across the antenna, providing DC power to an external load. The combination of a rectifying diode at the feedpoints of a receiving antenna is often referred to as a rectenna. Rectennas were originally proposed in the 1960s for power transmission by radio waves for remote powering of aircraft for surveillance or communications platforms. Conversion efficiencies greater than 85% have been demonstrated at radio frequencies (efficiency defined as DC power generated divided by RF power incident on the device). Later, concepts were proposed to extend the rectennas into the IR and optical region ...
An energy saving dc-dc converter circuit is disclosed having two energy efficient means which operate in tandem, an energy conserving means and a voltage doubling means. These energy efficient means are applied in combination with elements commonly found in dc-dc converter circuits, namely an ac voltage generator, a transformer for stepping up the generated ac voltage, and means for storing the converted dc voltage. The energy conserving means is connected to the dc voltage storage means. It comprises a resettable inhibit circuit which cuts off the provision of dc voltage for conversion for a predetermined interval when the output of the converter exceeds a predetermined level. The voltage doubling means is reponsive to outputs of the inhibit circuit of the energy conserving means and the ac voltage generator. It provides a phase inverted waveform of the generated ac voltage on one ...
The influence of electron-beam irradiation on mechanical properties of commercial multilayer flexible packaging materials based on coextruded and laminated polypropylene (PP), low-density polyethylene (LDPE), ethylene vinyl alcohol copolymer (EVOH) and poly(ethylene terephthalate) (PET), irradiated with doses up to 120 kGy, was studied. The tensile strength and elongation at break of the irradiated PET/PP film increase, while the penetration and sealing resistance decreased. In addition, the irradiated PET/LDPE/EVOH/LDPE film presented increase in the tensile strength on some radiation doses and decrease of the penetration and sealing resistance, except for sealing resistance at radiation dose of 15 kGy that resulted in a slight increase of ca 4%.
A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.
In radiation processing of food, the product often has to be prepackaged to prevent microbial recontamination during and after irradiation. The packaging material is exposed to radiation during radiation processing and radiation stability is a key consideration in the selection of packaging materials. The effects of ionizing radiation on many food packaging materials at the dose levels recommended for food precessing can be minimized by selecting appropriate radiationresistant materials. It is important to select materials in which chemicals formed as a result of the radiation treatment do not migrate and interact with the food, affecting its organoleptic and toxicological aspects. It is also important to select materials in which the physical properties are not altered to the extent they cannot ...
The activation of nuclear factor-kappa B1 (NFκB1) in cancer cells may confer resistance to ionizing radiation (IR). To enhance the therapeutic efficiency of IR in lung cancer, we screened for...Full Text Available
The titers of several preparations of kuru. Creutzfeldt-Jacob disease, and scrapie viruses were reduced by only 1/10th or less by high doses of gamma radiation of 50 kGy and by only 1/10th-1/1000th...Full Text Available
The structural variations of amorphous metals, such as Pd/sub 80/Si/sub 20/, with irradiation of helium ion, neutron, and gamma ray have been mainly pursued by the method of X-ray diffraction and thermal analysis. It should be noticed that the amorphous metals show a radiationresistance, that is, no remarkable structural changes under helium ion, neutron, and gamma ray irradiation.
Statoil is operating an increasing number of offshore and onshore pipelines in the North Sea area and elsewhere. Cathodic protection is a significant part of the corrosion management for these lines and we have collected a significant amount of experience with respect to design and operation of the systems. This paper deals with our comprehensive program for the onshore cathodic protection systems and the various challenges in different countries with respect to technical matters, such as operating conditions and different terrain. Generally, the systems are based on automatically controlled rectifier systems with a wide range of current drainage and very comprehensive monitoring of potentials and current flowing. The use of coupons, polarisation cells and buried reference cells are essential, as well as the use of intensive measurements along the route. The use of online monitoring of selected test posts and all rectifier units is considered essential for remote areas and in a ...
We have fabricated MgB_2 dc SQUIDs (superconducting quantum interference devices) containing inter-grain nanobridges as Josephson elements by a focused ion beam (FIB) etching method and measured their transport properties. The entire structure including the SQUID loop was patterned only using a FIB. The beam energy was 30 kV and the current was 0.9 nA for larger structures and 34 and 1.5 pA for the nanobridge pattern. Each bridge with a nominal width of 100 nm crossed a single grain boundary in the normal direction. The SQUID loop had a 3.1 #mu#m x 3.1 #mu#m hole with a 2 #mu#m average linewidth, corresponding to an inductance of 5.1 pH. The nanobridges had a two-step transition with an increase in the resistivity of more than a decade and a substantial decrease in the critical current density. Current-voltage characteristics showed a resistively shunted junction behavior at all temperatures below T_c, which implies that ...
DC -11/29/10 Remarks to the Press on Release of Purportedly Confidential Documents by Wikileaks; Secretary of State Hillary Rodham Clinton; Treaty Room; Washington, DC -11/29/10...
AC/DC voltage standards based entirely on solid-state references used as secondary, working, or transfer standards is widespread, although metrological performance is typically defined only via comparison with a higher level standard. The present report shows the improvements of the output metrological characteristics of an ac/dc calibrator by establishing three internal hierarchical levels of dc voltage references and by constant calibration of ac measuring circuits.
Microbes have been isolated and identified from spent nuclear fuel storage pools at the Idaho National Engineering and Environmental Laboratory (INEEL). Included among these are Corynebacterium aquaticum, Pseudomonas putida, Comamonas acidovorans, Gluconobacter cerinus, Micrococcus diversus, Rhodococcus rhodochrous, and two strains of sulfate-reducing bacteria (SRB). We examined the sensitivity of these microbes to a variety of total exposures of radiation generated by a 6-MeV linear accelerator (LINAC). The advantage of using a LINAC is that it provides a relatively quick screen of radiation tolerance. In the first set of experiments, we exposed each of the aforementioned microbes along with four additional microbes, pseudomonas aeruginosa, Micrococcus luteus, Escherchia coli, and Deinococcus radiodurans to exposures of 5 x 10{sup 3} and 6 x 10{sup 4} rad. All microbial specimens withstood the lower exposure with little or no reduction in cell ...
We made Basic designs of neutron guide, choppers, and detectors in order to optimize the design parameters of DC-TOF to be built in the HANARO Cold Neutron Guide Hall. In addition, we calculated the expected performance of DC-TOF using Monte Carlo simulations and evaluated the properties of neutron beam. Based on the results we obtained, we have compared the expected performance of the DC-TOF with those of existing instruments overseas. In conclusion, we believe that we will be able to construct the DC-TOF at HANARO as one of the best instruments of its kinds and it will become an invaluable instrument to researchers in the related field.
Poly(lactic acid) (PLA) is attractive as a substitute for classical polymer packaging material due to its biodegradability and sufficient mechanical and barrier properties. Presented research was focused on the changes of basic mechanical parameters after ionizing irradiation performed with doses in the range of 2.5-25 kGy, commonly used in radiation sterilization and preservation of foods. Two commercial available PLA packaging films were tested. The influence of radiation dose on the mechanical properties - tensile strength and elongation were determined using standardized methods. Radiationresistance of PLA is sufficient for packaging applications. The investigations of gas products of radiolysis of PLA have been made by gas chromatography after electron beam (EB) irradiations. (authors)
Radiation damage of the final optical components in an Inertial Confinement Fusion (ICF) reactor is a crucial issue for development of a laser-fusion reactor. To some extent, this problem will be encountered in the National Ignition Facility (NIF), but there, the integrated radiation dose will be considerably less than that encountered in a future reactor. This extremely harsh radiation environment necessitates shielding the ICF optics from direct neutron and x-ray bombardment. Several approaches have been suggested, such as the use of grazing incidence metal mirrors or fused silica wedge deflectors. While metal mirrors can withstand a larger radiation dose, their focusing qualities pose problems. Therefore wedge deflectors, originally suggested by Lawrence Livermore National Laboratory (LLNL) staff, represent a promising alternative. Radiation hardening of the fused silica ...
In order to qualify corrosion resistant materials for high level waste (HLW) packagings acting as a long-term barrier in a rock salt repository, the corrosion behaviour of the preselected materials Ti 99.8-Pd, Hastelloy C4 and two unalloyed steels was investigated. The resistance of the materials to general corrosion, local corrosion and stress corrosion cracking was examined under postulated accident conditions in the repository by long-term immersion tests of up to 4 years duration and electrochemical methods. The parameters investigated were different salt brines, temperatures of 90 deg. C, 170 deg. C and 200 deg. C as well as a gamma radiation field of 10"3Gy/h (10"5rad/h). Among the materials studied, Ti 99.8-Pd exhibited the highest corrosion resistance. This material corroded at a very low rate (radiation, and proved to be ...
The ability of the R46 R factor and its derivative pKM101 to modify sensitivity to "6"0Co #gamma# radiation was studied. In Escherichia coli K12 both plasmids enhanced bacterial survival after "6"0Co #gamma# irradiation. This effect was dependent on recA"+ genotype but not on recB"+, recB"+recC"+, and recF"+ genotypes. 5-Fluorouracil eliminated the R46 R factor from the parent and its rec"- mutant strains. These strains lost not only the antibiotic resistance coded for R46 R factor but their radioresistance as well.
A wood-polymer composite has been produced by impregnating the wood with the monomer and subsequently polymerizing it by exposure to a gamma radiation source. To compare the improvement in creep deformation of the wood due to the polymer impregnation, a nonlinear Norton-Bailey isothermal mathematical function has been used to model the bending creep deformation of the wood-polymer composites. Results show that the impregnation significantly improves the creep resistance of the wood. The maximum creep resistance is obtained when the amount of polymer impregnation exceeds about 30%. An interfacial interaction between the wood cell wall and the polymer could explain the creep deformation improvement, as well as the maximum impregnation level beyond which little improvement occurs. The results indicate that polymer impregnation is a viable method for improving the poor creep properties of wood. (author).
Polymers are required to use in radiation environments as insulation materials. However, they often suffer from tracking failure. There is an increasing demand to evaluate radiation effects on dielectric performance. This paper presents a recurrence plot (RP) approach to analyse surface discharge sequences of gamma-ray irradiated polymer materials based on tracking test. Studying the non-linear characteristics of discharge sequences can assist in understanding the underlying mechanism of the discharge process. Discharge sequences of the test are extended to m-dimensional phase space by using the phase space reconstructed method. As test samples, polybutylene terephthalate (PBT) and polybutylene naphthalate (PBN) were irradiated to 100 kGy and then up to 1 MGy with a dosage rate of 10 kGy h{sup -1} by using a {sup 60}Co gamma source. The tracking tests were carried out according to the test method described in IEC60112. It is found that the RPs ...
This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup ...
This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N_2/H_2) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup ...
Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were tested. Plasma nitriding and ageing, carried out at 500 deg. C for times ranging between 2 and 8 h, increased the surface hardness up to 1000 HV, producing case depths between 100 and 200 {mu}m. The core hardness of solubilized samples increased from 30 to 39 Rockwell C after the plasma nitriding treatment proving the possibility of nitriding and ageing at the same treatment cycle. The pre-aged samples did not show any overageing after the simultaneous plasma nitriding and ageing treatments. The corrosion resistance after plasma ...
Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were tested. Plasma nitriding and ageing, carried out at 500 deg. C for times ranging between 2 and 8 h, increased the surface hardness up to 1000 HV, producing case depths between 100 and 200 #mu#m. The core hardness of solubilized samples increased from 30 to 39 Rockwell C after the plasma nitriding treatment proving the possibility of nitriding and ageing at the same treatment cycle. The pre-aged samples did not show any overageing after the simultaneous plasma nitriding and ageing treatments. The corrosion resistance after plasma ...
In this paper, we report on a series of experiments designed to study the influence of plasma nitriding on the mechanical properties of austenitic stainless steel. Plasma nitriding experiments were conducted on AISI 304L steel in a temperature range of 375-475 C using pulsed-DC plasma with different N{sub 2}-H{sub 2} gas mixtures and treatment times. Firstly the formation and the microstructure of the modified layer will be highlighted followed by the results of hardness measurement, adhesion testing, wear resistance and fatigue life tests. The modified surface was analyzed directly after plasma nitriding as well as using a depth profiling method. The microhardness after plasma nitriding is increased up to 19 GPa, that is a factor of five higher compared to the untreated material (3.3 GPa). The adhesion is examined by Rockwell indentation and scratch test. No delamination of the treated layer could be observed. The wear rate after plasma ...
Abstract We have experimentally and theoretically investigated the equivalent magnetic noise in a magnetoelectric Metglas/ 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 laminate sensor unit by considering the constituent noise sources of dielectric loss (NDE) and DC leakage resistance (NR). In the low frequency range (f = 1 Hz), theory predicts that NR dominates the noise charge (1.6 times larger than NDE), with a 1 Hz noise of 9.1\\;{\\rm pt}/\\sqrt {\\rm Hz}. The experimental equivalent magnetic noise was 10.8\\;{\\rm pt}/\\sqrt {\\rm Hz}. This observed value is slightly higher than the predicted one, which might be due to an oversimplification of the theoretical model in terms of electrical charge amplifier and external vibration noise sources. ( 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Based on the results obtained for C-N and Si-C-N films, a systematic investigation of reactive magnetron sputtering of hard quaternary Si-B-C-N materials has been carried out. The Si-B-C-N films were deposited on p-type Si(100) substrates by dc magnetron co-sputtering using a single C-Si-B target (at a fixed 20% boron fraction in the target erosion area) in nitrogen-argon gas mixtures. Elemental compositions of the films, their surface bonding structure and mechanical properties, together with their oxidation resistance in air, were controlled by the Si fraction (5-75%) in the magnetron target erosion area, the Ar fraction (0-75%) in the gas mixture, the rf induced negative substrate bias voltage (from a floating potential to -500 V) and the substrate temperature (180-350 deg. C). The total pressure and the discharge current on the magnetron target were held constant at 0.5 Pa and 1 A, respectively. The energy and flux of ions bombarding the ...
The foils of various materials were irradiated with "6"0Co with an activity of 11,538 TBq. The minimum radiation dose was 25 kGy. Changes in chemico-physical properties were evaluated by infrared spectroscopy and were not detected after irradiation with 25 kGy. Packing foils were subjected to the following tests: mechanical tests, tests of weld strength, tests of impact resistance, free fall tests, permeability tests for water vapour and microbiological tests. The results of all tests were tabulated. The tests showed that the foils are impermeable for microorganisms and provided the welds are airtight the packed products remain sterile. (J.P.).
The ion nitriding treatment is a process widely used in steel alloys to improve the material's properties; such as surface hardness, resistance to wear, fatigue life and resistance to corrosion. But geometric changes in the components can produce during the nitriding process different effects on the behavior of the plasma, such as local variations in the electric field, an empty cathode effect, etc. These in turn can affect among other factors the local temperature and therefore the kinetics of the process, generating variations in the compound layer thicknesses and zone of diffusion, and micro-hardness profile. These heterogeneities limit the effectiveness of the plasma nitriding process, where control and duplication of the surface modification are most important. This work aims to study the effect of the geometry of the pieces treated with ionic nitriding, especially the effect of the orifices. An understanding of the operating mechanisms is ...
In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10"2 #approx# 10"5 Gy/yr and 10"1"1 #approx# 10"1"4 n/cm"2/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiation hardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and "6"0Co #gamma#-rays in the region of the neutron fluence from 1 x 10"1"1 to 5 x 10"1"3 n/cm"2 and the integrated #gamma#-ray dose from 890 to 10"5 Gy, ...
A thermal-resistantradiation sensing system using optical fiber has been developed. The system is for monitoring progress of chemical decontamination and able to measure the gamma-ray level in a hot solution of decontamination chemicals in situ. Our sensor head makes use of thermal-resistant NaI (T1) and it is connected to an optical fiber bundle. Scintillation photons pass from the NaI (T1) into the end of the bundle. This part of the system can withstand temperatures of over 100degC. At the far end of the optical fiber bundle, the scintillation photons are converted into fluorescent photons using a wavelength-shifting fiber. These photons are transferred to a distant photomultiplier tube through two thin transparent optical fibers. Furthermore, we propose a self-compensation technique for the dependence of scintillator sensitivity on. This compensation method is based on the correlation between temperature, sensitivity, ...
Bone marrow is one of the most radiosensitive organs. Irradiation causes a marked decrease in the total number of hematopoietic cells in the bone marrow. The reticular meshwork structure of marrow stromal cells, however, is relatively resistant to irradiation. Unimpaired stromal cell structure has been thought to be a prerequisite for the repopulation of hematopoietic cells during recovery from the effects of irradiation. The reticular framework is maintained by cell adhesion apparatuses such as gap junctions. The in vitro radiobiologic survival values of a cloned stromal cell line, H-1/A, were studied (n = 1.8, D0 = 138 cGy). Radiation doses of up to 4000 cGy had no detectable effects on the production of colony-stimulating factor 1. H-1/A cells communicate with each other via gap junctions as determined by the sensitive dye-transfer method. Gap-junctional communication between H-1/A cells was resistant to different levels ...
Bone marrow is one of the most radiosensitive organs. Irradiation causes a marked decrease in the total number of hematopoietic cells in the bone marrow. The reticular meshwork structure of marrow stromal cells, however, is relatively resistant to irradiation. Unimpaired stromal cell structure has been thought to be a prerequisite for the repopulation of hematopoietic cells during recovery from the effects of irradiation. The reticular framework is maintained by cell adhesion apparatuses such as gap junctions. The in vitro radiobiologic survival values of a cloned stromal cell line, H-1/A, were studied (n = 1.8, D0 = 138 cGy). Radiation doses of up to 4000 cGy had no detectable effects on the production of colony-stimulating factor 1. H-1/A cells communicate with each other via gap junctions as determined by the sensitive dye-transfer method. Gap-junctional communication between H-1/A cells was resistant to different levels ...
The radiation polymerization of multifunctional unsaturated polyester-monomer mixtures in wood forms interpenetrating network system. The mechanical resistance (compression, abrasion, hardness, etc.) of these composite materials are generally well over the original wood, however the impact strength is almost the same or even reduced, in comparison to the wood itself. An attempt is made using elastic polyester resins to produced wood-polyester composite materials with improved modulus of elasticity and impact properties. For the impregnation of European beech wood two types of elastic unsaturated polyester resins were used. The exothermic effect of radiation copolymerization of these resins in wood has been measured and the dose rate effects as well as hardening dose was determined. Felxural strength and impact properties were examined. Elastic unsaturated polyester resins improved the impact strength of wood composite ...
Nickel ion radiation at 500 C was shown to have a strong effect on the surface electrochemistry and intergranular corrosion (IGC) of stainless steel (SS). Measured current densities in a 1 N sulfuric acid solution at room temperature were increased at active-passive, passive, and transpassive potentials. Radiation effects on the current decay behavior and susecptibility to IGC were similar for a fine-grained (FG) S alloy and for a very large-grained (LG) SS. Radiation-induced segregation (RIS) at the surface was believed to promote higher currents at short times, whereas segregation at grain boundaries was responsible for IG attack. Analytical electron microscopy (AEM) measurements revealed chromium and iron depletion plus Ni and silicon enrichment at grain boundaries in irradiated specimens. Si enhanced dissolution at transpassive potentials, whereas Cr depletion did the same at active-passive and passive potentials.
We have observed resonant changes in the current-voltage characteristics of miniband semiconductor superlattices when the Bloch frequency is resonant with a terahertz field and its harmonics: the inverse Bloch oscillator effect. The resonant feature consists of a peak in the current which grows with increasing laser intensity accompanied by a decrease of the current at the low bias side. The peak position moves linearly with the laser frequency. When the intensity is increased further the first peak starts to decrease and a second peak at about twice the voltage of the first peak is observed due to a two photon resonance. At the highest intensities we observe up to a four photon resonance. A superlattice is expected to show negative differential conductance due to the strong nonparabolicity of the miniband. In this situation the carriers should undergo Bloch oscillations with a frequency {omega}{sub B} = eEd/h. Transient Bloch oscillations of photo excited carriers have been observed ...
Washington, DC -07/24/09 Photo: Secretary Clinton and Iraqi Prime Minister al-Maliki at HCC Bilateral; Washington, DC -07/24/09 Photo: Secretary Clinton at Joint Press...
The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the ...
Ramsar, a city in the northern Iran, has the highest level of natural background radiation in the world. It has been clearly shown that low doses of ionising radiation can induce resistance to subsequent higher exposures. This phenomenon is termed radioadaptive response. We have compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-ray occupational exposure as conditioning doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in normal background radiation areas, 15 healthy individuals from Talesh Mahalleh, a region with extraordinary high level of background radiation, and 7 X-ray radiographers working in Ramsar hospital located in normal natural background ionising radiation area were evaluated. Peripheral blood samples were prepared ...
A dc-to-dc converter has been designed which employs the synchronizing phenomenon in the transistor core multivibrator. In the proposed circuit, the voltage feedback is applied from the control transistor and the current feedback is applied from the main transistor. The operation of the converter is analyzed by the averaging method of the state space technique. The converter features small switching loss and is suitable for high frequency operation. An efficiency of more than 95% is obtained for 5 V, 3 A output at a switching frequency of 200 kHz.
The pure xenon dc positive column discharge has been characterized for various xenon pressures, currents, and discharge tube radii. The absolute output at the 147 nm resonance transition has been measured using two independent techniques to yield the radiant emittance at 147 nm (power per unit surface area). The efficiency of 147 nm production is obtained by combining the measured radiant emittance with the measured electrical power per unit length deposited in the gas. The radiant emittance and the efficiency are the two principle figures of merit for characterizing the discharge as a source of VUV radiation. It is observed that the trends in efficiency and radiant emittance change substantially when the discharge transitions from two-step electron impact excitation/ionization at higher pressures to single-step electron impact ionization at lower pressures. Modeling of the xenon positive column discharge yields radiant emittance and efficiency ...
Total hemispherical emittance was measured for the SP-100 reactor fuel cladding alloy (Nb-l% Zr). Based on a standard test method (ASTM C 835-82), experiments were conducted on a reference sample of oxidized stainless steel and then on a sample of actual cladding. The sample is heated in a vacuum by passing DC current through it until reaching equilibrium. Measurements are made of the electrical power dissipated in the sample and of the surface temperature. Using the Stefan-Boltzmann Law and some key assumptions concerning conductive and radiative heat transfer, the measured quantities are used to calculate emittance. Calculated values for unoxidized cladding range from 0.159 +/- 5.35% at 913 K to 0.200 +/- 4.51% at 1091 K. Highest value measured after onset of visible oxidation was 0.339 +/- 3.92% at 1269 K.... SP-100, Reactor, Emittance, Niobium, Fuel cladding, Emissivity.
This thesis discusses an advanced dynamical two-dimensional cylinder symmetric model for the high temperature part of the carbothermic silicon metal process, and its computer encoding. The situation close to that which is believed to exist around one of three electrodes in full-scale industrial furnaces is modelled. This area comprises a gas filled cavity surrounding the lower tip of the electrode, the metal pool underneath and the lower parts of the materials above. The most important phenomena included are: Heterogeneous chemical reactions taking place in the high-temperature zone (above 1860 {sup o}C), Evaporation and condensation of silicon, Transport of materials by dripping, Turbulent or laminar fluid flow, DC electric arcs, Heat transport by convection, conduction and radiation. The results from the calculations, such as production rates, gas- and temperature distributions, furnace- and particle geometries, fluid flow fields etc, are ...
Since 1958, the AlliedSignal Federal Manufacturing and Technologies (FM and T) Metrology Department has developed measurement technology and calibration capability in four major areas of measurement: mechanical; environmental, gas, liquid; electrical (D.C., A.C., RF/microwave); and optical and radiation. The capabilities developed include unique capabilities in many areas of measurement and engineering expertise to develop measurement techniques and resolve measurement problems in these major areas. FM and T Metrology was established in 1958 to provide a measurement base for the Department of energy`s Kansas City Plant. The Metrology Engineering Department provides the expertise to develop measurement capabilities for virtually any type of measurement which falls into the broad areas listed above. The engineering staff currently averages almost 16 years of measurement experience. A strong audit function has been developed to provide a means to ...
The electrical conductivity of Vitox-alumina (99.2%), Wesgo-alumina (99.9%) and AlN (99.6%) has been measured during and after irradiation with an experimental set-up which allows fusion relevant loading conditions. All irradiations were performed in high vacuum at 450 C using a 104 MeV {alpha}-particle beam with an applied DC electric field of 100 kV/m. In the high purity Vitox-alumina the in-situ and postirradiation bulk conductivities {sigma} and {sigma}{sub 0} show the highest irradiation induced electrical breakdown ever observed. The saturation level near 4 x 10{sup -2} ({Omega}m){sup -1}, reached already after 0.015 dpa (O-sublattice), is already above the critical value necessary to avoid MHD pressure drop with 10 {mu}m coatings in flowing liquid metal coolants. Under the same conditions no radiation induced electrical degradation at all has been found in Wesgo-alumina and AlN. (orig.).
Aluminum nitride has been proposed as electrically insulating coating in connection with blankets made of vanadium alloys. Irradiations were performed with an applied DC electric field of 100 kV/m, using a 104 MeV {alpha}-particle beam. The dose achieved were 0.1 dpa at 300 C, 0.05 dpa at 400 C, and 0.06 dpa at 500 C. The out-of-beam conductivity {sigma}{sub 0} decreased at all temperatures employed during early stage of irradiation. Before 0.02 dpa had been reached, {sigma}{sub 0} dropped to low values of typically (2-4) x 10{sup -11} ({Omega} m){sup -1}. Although a moderate increase can be observed during further irradiation, {sigma}{sub 0} remained below the initial value of the unirradiated specimen for all temperatures. That is, there is no significant evidence for radiation induced electrical degradation. The in-beam conductivity {sigma}, measured continuously during irradiation, also decreased by at least one order of magnitude. Relevant ...
Wood sawdust has been applied to manufacture the sawdust-clay-plastic composite (SDCPC) by radiation process for the purpose of disposing large amount of wood sawdust waste material. The process comprises the impregnation of liquid vinyl monomers into the completely dried molded sawdust-clay specimens followed by exposure to Co-60 gamma-radiation to induce graft-copolymerization of the impregnated vinyl monomers onto the sawdust-clay matrix. The comonomer system of unsaturated polyester and vinyl compounds was found to be the ideal impregnating monomer for the preparation of the SDCPC from the viewpoint of the technological and economical advantages. The SDCPC material has a variety of the sawdust content which enables the composite to have wide range of mechanical properties, e.g., 410 to 1100 kg/cm/sup 2/ in compressive strength, 120 to 380 kg/cm/sup 2/ in tensile strength and 0.32 to 4.41 kg/mm/sup 2/ in static bending strength. The SDCPC ...
The application of robotics for repair, refurbishing or dismantling of nuclear installations implies eventually severe radiationresistance requirements on embarked components and subsystems. This is particularly critical when optical sensing is considered. Optoelectronic components and optical fibers are indeed quite sensitive to radiation, and without special design are rapidly out-of-operation in such an environment. This paper reports the results of a series of #gamma# irradiation experiments on such devices, and identify their behavior under radiation. Test results show that carefully selected optical fibers can keep their radiation induced attenuation lower than 0.3 dB/m even up to a total dose of 10 MGy. Temperature annealing can even lower this attenuation down to 0.1 dB/m. On the other hand, commercially available light emitting diodes and photodiodes present attenuations ...
This study evaluates the effect of gamma radiation on the viability of fungi and actinomycetes that contaminate medicinal plants. The relationship between the total lipids of some fungi and actinomycetes and their sensitivity to gamma radiation is also investigated. The data reveal that the viable counts of these florae decrease approximately exponentially with the radiation dose, the effective dose for the elimination of these microorganisms being about 5 kGy for all the medicinal plants under study. Response of pure cultures of fungi and actinomycetes isolated from medicinal plants to increasing absorbed doses of gamma radiation indicate that an increase in radioresistance is in the following order: Streptomyces rimosus, Fusarium solani, Nocardia kuroishii. F. oxysporum, A. fumigatus, A. flavus, A. parasiticus and A. ochraceus. The total lipid contents of molds and actinomycetes have been reported to ...
Dendritic cells (DC) are the most potent antigen-presenting cells and play a central role in the induction of antiviral immune responses. Recently, we have shown that monocyte-derived DC (MoDC) from...Full Text Available
When a bipolar HVDC transmission system is operating monopolar using the earth as a return path, it is often desired to divert the return current from the earth to the line from the unused pole. To do so requires either that the system be shut down temporarily or that a dc circuit breaker be used. This paper describes the development of such a new dc circuit breaker, and its application on the Pacific Intertie as a Metallic Return Transfer Breaker (MRTB).
Four 10 MW, highly-stabilized power supply modules have been installed at the National High Magnetic Field Laboratory in Tallahassee, FL, to energize water-cooled, resistive, high-field research magnets. The power supply modules achieve a long term current stability if 10 ppM over a 12 h period with a short term ripple and noise variation of <10 ppM over a time period of one cycle. The power supply modules can operate independently, feeding four separate magnets, or two, three or four modules can operate in parallel. Each power supply module consists of a 12.5 kV vacuum circuit breaker, two three-winding, step-down transformers, a 24-pulse rectifier with interphase reactors, and a passive and an active filter. Two different transformer tap settings allow rated dc supply output voltages of 400 and 500 V. The rated current of a supply module is 17 kA and each supply module has a one-hour overload capability of 20 kA. The isolated output ...
Nanocomposites comprising nanocrystal silicon (Si), disordered carbon (DC), and multi-walled carbon nanotubes (MWCNTs) - denoted as Si/DC/MWCNTs - have been prepared by pyrolyzing the phenol-formaldehyde resin (PFR) mixed with Si and MWCNTs. This nanocomposite anode material showed a discharge capacity of 1216 mAh/g in the first cycle, and a charge capacity of 711 mAh/g after 20 charge-discharge, much higher than that of Si/DC composite. It can be observed that Si particles wrapped in MWCNTs were homogeneously embedded into the matrix of the DC. The improved electrochemical performance is hypothesized to be mainly attributed to the morphology stability of the composite due to the excellent resiliency and distinct electric conductivity of the MWCNTs.
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)
Wood plastic composite (WPC) of kadom, simul, mango and debdaro were prepared with two monomers methylmethacrylate (MMA) and butylmethacrylate (BMA) using high energy ionizing radiation. X-ray diffraction and scanning electron microscope (SEM) studies reveal that significant grafting occurred with wood fiber. Electric properties like resistivity and dielectric constant of both wood and WPC were measured under different moisture contents and relative humidities. The resistivities of wood decreased dramatically with increase of moisture content, but those of WPC decreased very slowly with moisture content. The dielectric constant of wood increased significantly with moisture content but no significant difference was observed in the case of WPC within the range of moisture contents studied. The dielectric constants of untreated wood also increased with their densities. (author).
Full text: As you know, thin films which generate anomalous big photovoltage (APhV) , as film photo resistive structures made of the combinations of A_2B_6 respond to X-ray and #gamma#- radiations. In this work the influence of X-ray and #gamma#-radiations on the quantity of APhV in the system APhV-film-photoresistor was investigated. Earlier polycrystal films with anomalous photo voltage properties were received only on the clean and flat surface with high isolation property (R>10"1"4 #OMEGA#). We worked out the technology of receiving APhV films CdTe on the surface of the photosensitive film CdS. The main condition under which this effect may be observed is that the lining must be slant concerning to the direction of the motion of evaporated substance's molecular bunch during the growing of the film, i.e. received film must have a dendritic structure. That is why photosensitive film CdS was received with thermo vacuum ...
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 materials estimated ...
Consideration is given to the data, demonstrating the effect of ion radiation on strength characteristics of ionic crystals, presented by magnesium oxide. Crystals, prepared in the form of plates, were irradiated by Si"+, Fe"+, C"+ ions by the dose of 10"1"6-10"1"7 ion/cm"2 at room temperature in vacuum. The following characteristics were investigated: dislocation density, microhardness, crack resistance. Investigation of dislocation structure showed, that dislocation density in irradiated sample was 2-3 times higher, as compared to nonirradiated one. Sufficient increase of fracture viscosity of MgO crystals was revealed. It can be conditioned by occurrence of compression stresses in the surface layer, decelerating crack formation and propagation.
The radiosensitivity of spermatogonial stem cells of C3H/HeHx101/H F[sub 1] hybrid mice was determined by counting undifferentiated spermatogonia at 10 days after X-irradiation. During the spermatogenic cycle, differences in radiosensitivity were found, which were correlated with the proliferative activity of the spermatogonial stem cells. In stage VIII[sub irr], during quiescence, the spermatogonial stem cells were most radiosensitive with a D[sub 0] of 1.4 Gy. In stages XI[sub irr]-V[sub irr], when the cells were proliferatively active, the D[sub 0] was about 2.6 Gy. Based on the D[sub 0] values for sensitive and resistant spermatogonia and on the D[sub 0] for the total population, a ratio of 45:55% of sensitive to resistant spermatogonial stem cells was estimated for cell killing. When the present data were compared with data on translocation induction obtained in mice of the same genotype, a close fit was obtained when the translocation ...
This invention is concerned with a solar energy system for propelling aircraft. Obtained are forces for aerodynamic lift and impetus. The lifted body had a transparent upper surface for the sun light, but black or reflecting for IR-radiation and high thermal insulation properties. Inside of the lifted body, the air temperature increases and is lifted by convection influence. The air resistance of this body is low in horizontal direction and higher in vertical position. The payload could be shifted, so that the positive or negative angle of the whole body can be selected. By this principal it is possible to transform the static lifting force in a dynamic impetus.
Recently, a superconducting cryo-electron microscope in which specimens are cooled to the liquid helium temperature (4.2 K) has been developed. The main components and functional features of this new microscope are reported together with application data on polyethylene, poly (4-methyl-1-pentene), valonia cellulose, rock salt, ice crystallites and ceramic superconductor. The resistance to electron radiation damage, of beam-sensitive specimens including polymers has been increased more than ten times. Thus, the microscope has made it possible to take high resolution images and to analyze the crystal-structure of micro-areas. (orig.).
Polymer sealing parts are widely used in various branches of engineering as detachable joints that operate at normal and cryogenic temperatures. They are also used in nuclear-power engineering to seal pumps, pipelines, etc., where they operate at 600-650 K under a neutron fluence of around 10"1"6 cm"-"2 (E #>=# 0.18 MeV) and concomitant #gamma#-irradiation of about 10"6 R. The fluoroplastic-based materials currently used degrade when irradiated in water at 320-360 K with a neutron fluence of 10"1"5 cm"-"2 (thermal neutrons) or 10"1"4 cm"-"2 (fast neutrons), and a concomitant #gamma#-irradiation dose of 2 x 10"6 R. The strength of these fluoroplastics decreases markedly after #gamma#-irradiation (from a cobalt source) at room temperature at doses above 10"6 R. For this reason, flexible and swelling graphites are finding ever increasing application. Graflex foils made of extra-pure natural graphite were found to be radiation-resistant and suitable for use as seals ...
Etching of SiO_2 rods has been obtained with a dc torch with argon as the process gas in an air environment at atmospheric pressure; the high temperature of the plasma jet causes vaporization of the exposed area. The apparatus and torch operative parameters have been set up to obtain a depth etch rate of up to 0.6 mm min"-"1 corresponding to 0.826 g min"-"1. An enthalpy probe has been employed to monitor the plasma conditions before the thermal plasma etching process and from the experimental etch rate a surface rod temperature of T_s_u_r = 2057 K has been derived. Etching has been obtained with uniformity over the entire exposed area with peak to peak differences below 1%. The plasma to rod heat transfer has been simulated using a commercial CFD code Fluent (copyright). The model consists of a non-steady two-dimensional simulation for a compressible turbulent fluid, with an adapted grid calculation. Boundary conditions have been set out using the enthalpy probe ...
The latest electronic circuit technology that can be used for the electric railway traction system fed by an AC/DC dual power line was developed. This system consists of reverse conducting GTO thyristors, microprocessors, and DSP`s. In the AC power supply line section, the line converter is controlled by PWM technology to secure a high power factor and reduce the higher harmonic generation of an input current as far as possible. The line converter and motor converter use reverse conducting GTO thyristors. Since these converters are cooled using a heat pipe cooler, they are reduced in size and weight. The electric grounding point of the main power circuit is set to the negative side of the DC line for AC and DC line sections. Therefore, the AC/DC selector switch was simplified in structure. Moreover, the DC input for the auxiliary power supply can be obtained from multiple line ...
In response to the decisions adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (Kyoto conference for the prevention of global warming) of 1997, hybrid vehicles, electric vehicles, and the like are being announced of their completion or placed on the market one after another as low pollution vehicles with CO2 emission to cause global warming reduced. Fuji Electric Co., Ltd., is engaged in the development of a DC-DC converter for hybrid vehicles in cooperation with Nissan Motor Co., Ltd. The product is characterized in (1) that it is small in size and light in weight because a step-down converter and an emergency step-up converter are integrated; (2) that it enjoys a high efficiency rate of 89%; (3) that its service life is long thanks to its design free of aluminum electrolytic capacitors; and (4) that it is provided with various reliability improving features, such as protective systems and ...
Several commercially available capacitors were evaluated at the liquid nitrogen temperature (77 K). Our primary interest was their performance under a bias voltage when used as DC link capacitors in cryogenic power electronics. In general, the performance of polymer capacitors and certain ceramic capacitors is almost independent of the temperature, DC bias, and frequency. On the other hand, ceramic capacitors based on high dielectric constant materials showed a strong dependence on the boundary conditions. Aluminum electrolytic capacitors showed a dramatic decrease of capacitance at 77 K, possibly due to the electrolyte being frozen and therefore losing its conductivity.
Background: Incidence, characteristics and predictive factors of transient ST-segment changes after DC shock are poorly known. Methods: 91 consecutive pts referred for external cardioversion of atrial fibrillation (AF) (61 men, 69+/-10yo) were prospectively included. The presence of ST elevation or depression was assessed on 12 lead-ECG immediately after the first DC shock. Correlations with DC shock characteristics (monophasic/biphasic and energy), clinical variables, echocardiographic parameters, biological parameters, medications, anesthesic drugs as well with morphological features were made. Results: 18 and 20 pts underwent 200J or 300J monophasic and 53 pts 200J biphasic DC shocks. We found an incidence of 48% for ST-segment changes: 35% for ST elevation and 13% for ST depression. ST...
Jan 22, 2011 ... dc.description.abstract, The progress in the development of a surface analysis tool based on the excitation of characteristic luminescence ...
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Jan 14, 2004 ... presented to the nation at NASA Headquarters, Washington, D.C., ...... Board/Air Force Scientific Advisory Board Joint Task Force on ...
This project proposes to design and develop a new class of power converters (direct DC to AC) to drastically improve performance and optimize the cost, size, weight and volume of the DC to AC converter in SOFC systems. The proposed topologies employ a high frequency link; direct DC to AC conversion approach. The direct DC to AC conversion approach is more efficient and operates without an intermediate dc-link stage. The absence of the dc-link, results in the elimination of bulky, aluminum electrolytic capacitors, which in turn leads to a reduction in the cost, volume, size and weight of the power electronic converter. The feasibility of two direct DC to AC converter topologies and their suitability to meet SECA objectives will be investigated. Laboratory proto-type converters (3-5kW) will be designed and tested in Phase-1. A detailed design ...
The Systems Development Group and the Pharmacy Service of the Washington D.C. VAMC are involved in automating the administrative and clinical data requirements of a satellite out-patient pharmacy....Full Text Available
Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor (SC) DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work. (semiconductor integrated circuits)
Pages 184-197: Understanding Personal Change in a Women’s Faith-Based Transitional Center/title link ...titleUnderstanding Personal Change in a Women’s Faith-Based Transitional Center/dc:title
The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are ...
Radiation hardening and radiation-induced chromium (Cr) depletion were related to intergranular stress corrosion cracking (IGSCC) response among various stainless steels (SS). Available data on neutron-irradiated materials were analyzed and correlations developed between fluence, yield strength, grain-boundary Cr concentration, and cracking susceptibility in high-temperature water environments. Large heat-to-heat differences in the critical fluence (0.2 neutrons/cm"2 to 2.5 x 10"2"1 neutrons/cm"2) for IGSCC were documented. Variability often was consistent with yield strength differences among irradiated materials. IGSCC correlated better to yield strength than to fluence for most heats, suggesting a possible role for radiation-induced hardening (and microstructure) on cracking. However, isolated heats revealed a wide range of yield strengths (450 MPa to 800 MPa) necessary to promote IGSCC which could not be explained by ...
In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water to determine the irradiation-assisted stress corrosion cracking (IASCC) behavior of HTH Alloy X-750 and direct-aged Alloy 625. New data confirm previous results showing that high irradiation levels reduce SCC resistance in Alloy X-750. Heat-to-heat variability correlates with boron content, with low boron heats showing improved IASCC properties. Alloy 625 is resistant to IASCC, as no cracking was observed in any Alloy 625 specimens. Microstructural, microchemical and deformation studies were performed to characterize the mechanisms responsible for IASCC in Alloy X-750 and the lack of an effect in Alloy 625. The mechanisms under investigation are: boron transmutation effects, radiation-induced changes in microstructure and deformation characteristics, and radiation-induced segregation. Irradiation of Alloy X-750 ...
An overview of the developments and designs of electric cars is given. It can be concluded that the numbers of electric-powered vehicles in the world, presented by different companies, are confusing and that it is very difficult to categorize the electric cars because of the many different prototypes under development sofar. Also an introduction is given on the engine technology of such cars. Attention is paid to the direct current (DC) motor, the induction motor, the brushless DC-motor, and the synchronous motor. 2 figs., 4 ills., 35 refs.
Solutions have been found for the problems encountered with the coil power and switching systems of the International Fusion Superconducting Magnet Test Facility (IFSMTF). The coil power system provides the filtered dc sources (+- 12 V dc; 25,000 A) for charging and discharging the coils of the IFSMTF experiment. The switching system provides the means of transferring the coil current into a dump resistor when a rapid discharge of a coil is required due to a coil failure (quench) or other system abnormalities.
We have developed a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. We have demonstrated that these structures perform 2 to 5 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We present new testing results showing exceptional behavior at DC, with gradients in excess of 110kV/cm in vacuum.
Carbon dioxide is receiving renewed interest as an efficient and environmentally safe refrigerant in a number of applications, including mobile air conditioning and heat pump systems, and hot water heat pumps. Compact heat exchangers for CO{sub 2} systems are designed with small-diameter tubing. The purpose of this study is therefore to provide a better basis for understanding and predicting heat transfer and pressure drop during flow vaporization of CO{sub 2} in microchannels. The ''unusual'' properties of carbon dioxide give heat transfer and two-phase flow characteristics that are very different from those of conventional refrigerants. Examples of these differences are the much higher pressure, the resulting high vapour density, a very low surface tension, and a low liquid viscosity. High pressure and low surface tension has a major effect on nucleate boiling characteristics, and earlier test data have shown a clear dominance of nucleate boiling ...
Radiation chimeras in the early phase after bone marrow transplantation are a good model to study the efficiency of the body's nonspecific defense system represented by macrophages (M phi), polymorphonuclear cells (PMN), and NK cells. These cell types are present in large numbers in spleen and liver at that time, whereas the specific immune system represented by T and B cells is functionally deficient. We previously reported enhanced activities in vitro of M phi (and PMN) from recipient animals in an early phase after allogeneic bone marrow transfer. We here demonstrate that these activities result in enhanced spontaneous resistance against Listeria monocytogenes in vivo: CFU of L. monocytogenes in spleen and liver 48 h after infection were about 1 or 2 to 4 log steps less than in untreated control mice of donor or host haplotype. This enhanced resistance decreased over the 4-mo period after marrow transfer. Preactivated M ...
This paper presents a new grid connected inverter for fuel cells. It consists of a two stage power conversion topology. Since the fuel cell operates with a low voltage in a wide voltage range (25 V-45 V) this volt- age must be transformed to around 350-400 V in order to invert this dc power into ac power to the grid. The proposed converter consists of an isolated dc-dc converter cascaded with a single phase H-bridge inverter. The dc-dc converter is a current-fed push-pull converter. A new dedicated voltage mode startup procedure has been developed in order to limit the inrush current during startup. The inverter is controlled as a power factor controller with resistor emulation.Experimental results of converter efficiency, grid performance and fuel cell response are shown for a 1 kW prototype. The proposed converter exhibits a high efficiency in a wide power range (higher than 92%) and the inverter operates with a near ...
In this work a comprehensive metallophysical study was carried out for two aluminosilicide slip coatings of the systems Al-Si and Al-Nb-Si and an electron-beam Co-Cr-Al-Y coating on alloy EP-539 (17...19% Cr, 4...6% Co, 2.5...4% W, 4.5...6.5% Mo, 2...3% Ti, 3...4% Al, 1.4...2% Nb, balance Ni) after high-temperature testing. The protective properties of the coatings were evaluated from the results of laboratory tests for heat resistance at 1000/sup 0/C in the combustion products of diesel fuel with added sulfur at 970, 1000, and 1060/sup 0/C for 100 h and after full-scale tests for 150, 250, 400, and 700 h. Metallographic, hardness, x-ray, and micro x-ray studies of the coating were carried out. Layer-by-layer phase composition and the lattice spacing of the main phases were determined. X-ray analysis was carried out in an a DRON-1 diffractometer in copper K/sub ..-->../-radiation, and x-ray microanalysis was carried out in a MS-46 Cameca ...
Selected local woods and their wood-polymer combinations or composites (WPC) were tested for their thermal conductivity and their fire resistance. WPC were prepared by polymerizing monomers ''in situ'' in oven dried woods by gamma radiation. The monomers included acrylonitrile (AN), 60% styrene-40% acrylonitrile (STAN), methyl methacrylate (MMA), 95% methyl methacrylate-5% dioxane (MD), and vinylidene chloride (VDC). A reduction in thermal conductivity was exhibited by all the composites prepared. W-PAN showed the greatest reduction in thermal conductivity and W-PSTAN in general showed the least. An explanation is suggested for this behaviour. The polymers PMMA and PMD were found to enhance flammability of the woods while PVDC, PAN, and PSTAN imparted fire resistance to the woods. Of the six local woods studied, Ramin-and-Keruing-polymer composites showed the highest flammable tendencies ...
Considerations were given on typical applications of nylon resin parts to automotive use and their future trends through news topics. GF strengthened nylon resin is used in cylinder head covers substituting aluminum because of advantages in nylon resin of weight reducibility, vibration suppressibility, and noise shielding capability. Radiator tank uses N66GF 30% strengthened nylon in more than 60% of bonnet type passenger cars. Nylon resin is used most in harness connectors installed in locations that require heat resistance. External car parts such as bumpers, fenders, and wheel caps use to some extent nylon resin in the form of strengthened and up-graded polymer alloy. BMW in Germany used in its high-class production cars intake manifolds made of GF strengthened Nylon 66. The majority of engine{prime}s gas intake system parts has been replaced with Nylon blow-formed parts. The resin industry is aiming at developing Nylon resin with aromatic ...
A device for detecting neutrons includes a semi-insulated bulk semiconductor substrate having opposed polished surfaces. A blocking Schottky contact comprised of a series of metals such as Ti, Pt, Au, Ge, Pd, and Ni is formed on a first polished surface of the semiconductor substrate, while a low resistivity ("ohmic") contact comprised of metals such as Au, Ge, and Ni is formed on a second, opposed polished surface of the substrate. In one embodiment, n-type low resistivity pinout contacts comprised of an Au/Ge based eutectic alloy or multi-layered Pd/Ge/Ti/Au are also formed on the opposed polished surfaces and in contact with the Schottky and ohmic contacts. Disposed on the Schottky contact is a neutron reactive film, or coating, for detecting neutrons. The coating is comprised of a hydrogen rich polymer, such as a polyolefin or paraffin; lithium or lithium fluoride; or a heavy metal fissionable material. By varying the coating thickness and ...
This article described a full-scale green renovation project undertaken by a construction management firm in Newton, Massachusetts. Chapman Construction and Design began renovating its own office building in late 2007 and completed it in September 2008. The firm set out to achieve LEED Platinum certification from the United States Green Building Council. The project involved energy saving modifications to its mechanical systems; replacing plumbing fixtures with high efficiency alternatives to reduce water consumption by at least 40 per cent; installing skylights and additional windows to allow more natural light into the interior space; salvaging doors, lighting, metal studs and masonry whenever possible; and using sustainable products such as recyclable carpets, tiles and low-VOC paint. The main feature of the renovation was a new 47 kW (DC) photovoltaic (PV) solar power array installed on the rooftop. The PV array includes 208 panels and a SunPower SPR-225 system ...
The optically stimulated luminescence (OSL) results a highly appropriate dosimetric technique for readings of absorbed radiation 'in alive' and 'in situ', as well as in real time. The CVD diamond on the other hand presents excellent qualities like radiation reader thanks to its reproducibility, radiationresistance, biocompatibility and non toxicity. The present work studies the answer of two diamond films pure and polluted with nitrogen (750 ppm) grown by the Chemical Vapor Deposition method (CVD) on silicon substrate (001) irradiated with beta (Sr-90) in the 0.833-100 Gy interval. The optical stimulation was carried out by 40 seconds with infrared laser (830 nm, 0.36 W/cm{sup 2}) and the filter BG-39 (300-600 nm) coupled the PM. The intensity and the decay of the hyperbolic type of the LOE curves were similar in both samples, for the non doped diamond were observed ...
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 ...
Purpose/Objective: The role of programmed cell death (apoptosis) as a cellular response to cancer therapy such as radiation or chemotherapy is the subject of much study, and manipulation of the apoptotic response in tumor cells may be valuable in the treatment of a variety of cancers. Both p53 dependent and independent apoptotic pathways have been identified; p53 is mutated in at least 50 % of human cancers and a majority of radiationresistant tumors contain p53 mutations. This study is designed to examine the induction of programmed cell death in a human colon carcinoma cell line that possesses two mutated p53 alleles. Ionizing radiation alone, or in combination with the chemotherapeutic drug 5-fluorouracil (5-FU), were used to elicit the apoptotic response. This study will focus on whether these treatments can induce a significant apoptotic response in cells that have mutated p53 alleles. Materials ...
Thyroid cancer is the most frequently diagnosed endocrine cancer and causes more deaths than all other endocrine cancers combined. Research findings support the concept that a subpopulation of thyroid cancer cells displays properties characteristic of stem cells. These putative cancer-forming entities drive tumorigenesis as a result of their dual ability to undergo self-renewal and to differentiate into various types of cancer cells; they also mediate metastasis and are resistant to the effects of chemotherapy and radiation therapy. This Review discusses the cellular origin of thyroid cancer and the properties of the thyroid cancer stem cell niche. The article critically evaluates the methods used to identify molecular markers expressed by thyroid-cancer-initiating cells and outlines prosp...
Two of eight differently prepared copper stabilizer samples, previously irradiated in the RTNS-II at LLNL, the IPNS-1 and the BSR at ORNL, have been irradiated to a fluence of 1.33 /times/ 10/sup 22/ n/m/sup 2/ at RTNS-II. During the course of the irradiation the samples were periodically removed (without warming) for measurements of the transverse magnetoresistance and returned for continued irradiation. This experiment extends the range of neutron-irradiation-induced resistivity by a factor of five over the previous experiments. A simple model is developed which reproduces the magnetoresistance results of all the experiments to an accuracy of 2.5%. 13 refs., 6 figs.
Monte Carlo calculations of proton irradiation of permanent magnets for the TRADE experiment have been performed. An irradiation dose of about 4´106 Gy/yr/mA has been estimated due to beam losses in normal operating conditions. Existing experimental results indicate that this irradiation level may induce a considerable demagnetization: in fact, a dose of 6´107 Gy induces a remanence loss of 0.3 % on samples of Sm2Co17 magnets, which are the most resistant type. More detailed calculations with the final design of the magnets and of the beam line are suggested, to determine if the irradiation levels allowed a reliable operation of the permanent magnets for the entire duration of the TRADE experiment. Damage and gas production rates have also been calculated; the values obtained are very low, thus confirming that the demagnetization process is in great part reversible.
A plant for the fixation of high-level wastes in borosilicate glass has been operating in France since 1978. A large plant is under construction in the U.S. for the fixation of defence high-level waste and plans for other glass fixation plants are well advanced at several sites around the world. Among the reasons for the selection of borosilicate glass as a fixation medium are the relative ease of processing wastes of variable composition by means of well established technology, and the long-term radiation and thermal stability of the glass. Well formulated glass also has sufficient resistance to the action of groundwater so that it can serve as an important barrier against the spread of radionuclides via groundwater in any forseeable situation. Research is continuing to quantify the reactions of waste glass in site-specific geological repository environments.
Since actinide mononitride has several superior thermal and neutronic properties, nitride fuel is considered as a candidate for future nuclear systems, such as advanced fast reactors and accelerator-driven system. Establishing reprocessing technology is one of key technologies for the development of nitride fuel cycle. In addition to general advantages of pyrochemical process, such as the potential for economy, radiation and proliferation resistance, recycling of N-15 in nitride fuel seems to be practical in comparison with conventional hydro-process. Following the electrochemical measurements of nitride fuel in LiCl-KCl molten salt, the experimental study on closing nitride fuel cycle has been carried out in JAEA by used of TRU nitride and burnup simulated nitride samples. Recent progress of the study is summarized in this paper.
A technique for the measurement of the total hemispherical emittance of pipe surfaces is described, and design and operational details are given. The technique is conceptually simple. A long test pipe (e.g., 3.4 m) is mounted concentrically inside a Pyrex glass pipe. The system is evacuated, and the test pipe is heated by means of an electrical resistance heater. Heat transfer from the test pipe to the enclosure is almost solely radiative, allowing an average emittance for the test pipe and the Pyrex pipe and the electrical power input to the heater. By varying the electrical power level, one can measure the test pipe emittance as a function of temperature. By using a simple correction to account for the finite length of the test pipe, one can calculate the results using the simple expression for infinite, concentric cylinders. Results agree with measurements by reflectance techniques and have a nominal relative error of less than 10%.
The determination of residual stress (RS) in case-hardened steel gear truck synchronisers coated with thermal sprayed molybdenum was carried out using neutron and synchrotron X-ray diffraction. Two samples with different coating thicknesses (about 120 ?m and 1.4 mm) and different steel substrates (16MnCr5 and SAE4140, respectively) were investigated. Microanalysis revealed substantial porosity in both samples and some debonding was observed between the thin coating and the substrate. The bulk hardness of the SAE 4140 proved to be much higher than the 16MnCr5 and the surface case-hardening increased it by a further 20%. The full three-dimensional stress depth-profile was determined by neutron diffraction (ND) in both the coatings and the substrates, while synchrotron radiation allowed a dep...
The dependence of the carrier concentrations, of the resistivity and of the Hall coefficient of irradiated silicon on the neutron fluences has been investigated, starting from the supposition that the main phenomena induced by irradiation in the semiconductor bulk are shallow-donor removal and deep-centres creation. The free parameters of the model are initial doping of the starting material, the permitted energy level values of the radiation-induced centres in the semiconductor band gap and their introduction rates. The influence of each parameter on the calculated dependences is studied in detail, for three cases: one deep acceptor-like centre, two deep acceptors and one deep acceptor plus one deep donor-like centre. each of the three cases is discussed in correspondence with different experimental results.
A vertical cavity surface emitting laser that emits visible radiation is built upon a substrate, then having mirrors, the first mirror on top of the substrate; both sets of mirrors being a distributed Bragg reflector of either dielectrics or other materials which affect the resistivity or of semiconductors, such that the structure within the mirror comprises a plurality of sets, each having a thickness of {lambda}/2n where n is the index of refraction of each of the sets; each of the mirrors adjacent to spacers which are on either side of an optically active bulk or quantum well layer; and the spacers and the optically active layer are from one of the following material systems: In{sub z}(Al{sub y}Ga{sub 1{minus}y}){sub 1{minus}z}P, InAlGaAs, AlGaAs, InGaAs, or AlGaP/GaP, wherein the optically active region having a length equal to m {lambda}/2n{sub eff} where m is an integer and n{sub eff} is the effective index of refraction of the laser ...
RADIANT{trademark} is manufactured by United States Surgical Corporation, Vascular Therapies Division, (formerly Progressive Angioplasty Systems). The system comprises a liquid {beta}-radiation source, a shielded isolation/transfer device (ISAT), modified over-the-wire or rapid exchange delivery balloons, and accessory kits. The liquid {beta}-source is Rhenium-188 in the form of sodium perrhenate (NaReO{sub 4}), Rhenium-188 is primarily a {beta}-emitter with a physical half-life of 17.0 hours. The maximum energy of the {beta}-particles is 2.1 MeV. The source is produced daily in the nuclear pharmacy hot lab by eluting a Tungsten-188/Rhenium-188 generator manufactured by Oak Ridge National Laboratory (ORNL). Using anion exchange columns and Millipore filters the effluent is concentrated to approximately 100 mCi/ml, calibrated, and loaded into the (ISAT) which is subsequently transported to the cardiac catheterization laboratory. The delivery catheters are modified ...
The authors have measured the magnetization of single-phase 90-K superconductors, GdBa_2Cu_3O/sub 6+#delta#/, EuBa_2Cu_3O/sub 6+#delta#/, and SmBa_2Cu_3O/sub 6+#delta#/ with a SQUID magnetometer. They have shown that, in the superconducting state, each magnetization-field curve exhibits a maximum at #approx# 100 G, followed by a linear increase of the magnetization with a slope only approximately one-fifth of the slope for a field smaller than 50 G. They have also investigated the effect of #gamma#-irradiation on YBa_2Cu_3O/sub 6+#delta#/, SmBa_2Cu_3O/sub 6+#delta#/, and have found that the radiation damage results in the appearance of a tail in the superconducting transition. They have also shown that the normal resistance decreases with increasing radiation exposure up to a dose of 10 Mrad.
The interference of hyperthermia and ionizing radiation, respectively, with the effects of capric (10:0), lauric (12:0), myristic (14:0), oleic (cis-18:1) and elaidic (trans-18:1) acids on the osmotic resistance of human erythrocytes was investigated. The results are summarized as follows: (A) not only at 37 degrees, but also at 42 and 47{degrees}C lauric acid (12:0) represents the minimum chain length for the biphasic behaviour of protecting against hypotonic hemolysis at a certain lower concentration range and hemolysis promotion at subsequent higher concentrations; (B) with increasing temperatures the protecting as well as the hemolytic effects occur at lower concentrations of the fatty acids; (C) the increase of temperature promotes the extent of hemolysis and reduces the extent of protection against hypotonic hemolysis; (D) Gamma-irradiation of erythrocytes selectively affects the concentration of oleic acid at which maximum protection ...
A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiationresistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found ...
The AP-0 Target Hall Collection Lens is a pulsed device which focuses anti-protons just downstream of the Target. Since the angles at which the anti-protons depart the Target can be quite large, a very high focusing strength is required to maximize anti-proton capture into the downstream Debuncher Ring. The current design of the Collection Lens was designed to operate with a focusing gradient of 1,000 T/m. However, multiple failures of early devices resulted in lowering the normal operating gradient to about 750 T/m. At this gradient, the Lens design fares much better, lasting several million pulses, but ultimately still fails. A Finite Element Analysis (FEA) has been performed on this Collection Lens design to help determine the cause and/or nature of the failures. The Collection Lens magnetic field is created by passing high current through a central conductor cylinder. A uniform current distribution through the cylinder will create a tangential or azimuthal magnetic field that ...
Because resistance to new insecticides may develop rapidly and cross resistance is often encountered, even between insecticides of different classes, there is a continual demand for the development...Full Text Available
Since the last review of the problem of insecticide-resistance was presented in this journal at the beginning of 1958, resistance has been discovered in 16 new species, and in at least 14 species both...Full Text Available
In APCs, presentation by MHC II molecules of the chemically dominant peptide from the protein hen egg white lysozyme (HEL) generates different conformational isomers of the peptide-MHC II complexes (pMHC). Type B pMHCs are formed in early endosomes from exogenous peptides in the absence of H2-DM, whereas in contrast, type A pMHC complexes are formed from HEL protein in late vesicles after editing by H2-DM. Thus, H2-DM edits off the more unstable pMHC complexes, which are not presented from HEL. In this study, we show that type B pMHC complexes were presented from HEL protein only after stimulation of dendritic cells (DC) with TLR ligands or type I IFN. Type I IFN contributed to most TLR ligand-induced type B pMHC generation, as presentation decreased in DC lacking the receptor for type I IFNs (IFNAR1(-/-)). In contrast, presentation of type A pMHC from HEL and from peptide was minimally affected by TLR ligands. The relative effectiveness of ...
TlGaSe_2 compound belongs to group of layered semiconductors of A"3B"3C_2"6-type. Photoelectric and optical properties of TlGaSe_2 single crystals were investigated in detail. Influence of gamma-, electron and neutron radiation on photoelectric properties of TlGaSe_2 single crystals is investigated too. The present work deals with experimental results relative to X-ray dosimetric characteristics of TlGaSe_2 crystals at 300 K. X-ray conductivity and X-ray dosimetric characteristic measurements are carried out in low load resistance regime. The source of X-ray radiation is the installation of X-ray diffraction analysis (URS-55a) with the BCV-2(Cu). Intensity of X-ray radiation (E) is regulated by measurement with current variation in tube at each given value of X-ray radiation dose E (R/min) are measured by crystal dosimeter DRGZ-02. X-ray conductivity coefficients K_#sigma# ...
HT-29 human colon tumor cells growing as spheroids have been evaluated as a model system for measuring the response of human colon tumor cell to antineoplastic agents. HT-29 cells have been capacity to form spheroids up to 1 mm or more in diameter when grown in spinner culture. The multicellular HT-29 spheroids develop hypoxic centers reflecting the cellular conditions found in human cancer treatment, i.e., nutritionally deficient hypoxic cells that are felt to be a significant source of both radiation and chemotherapy clinical treatment failures. Spheroids of increasing size were radiated and then dispersed into single cells for colony survival assay. Compared with irradiated single cell suspensions, the spheroid cells demonstrated a significant increase in radioresistance. Growing spheroids developed a complex radiation survival curve which was variable with respect to size of the spheroid. The drug 5-Fu was studied to ...
We have observed significant differences in the response to ionizing radiation of two closely related human cell lines, and now compare the effects on these lines of both low and intermediate LET radiation. Compared to TK6, WTK1 has an enhanced X-ray survival, and is also more resistant to cell killing by {alpha}-particles. The hprt locus is more mutable in WTK1 than in TK6 by both X-rays and {alpha}-particles. WTK1 is also more mutable by {alpha}-particles than by X-rays at the hprt locus. X-ray-induced mutation at the heterozygous tk locus in WTK1 is about 25 fold higher than in TK6, while {alpha}-particle-induced mutation is nearly 50 fold higher at this locus. Also, the slowly growing tk- mutants, which comprise the majority of spontaneous and X-ray-induced tk- mutants of TK6, were not induced significantly by {alpha}-particles. Previously, we showed that TK6 has a reduced capacity for recombination compared with WTK1, ...
A descriptive model and design procedure for the DC electromagnetic flow coupler is developed based on a quasi-one-dimensional analysis previously developed for the DC electromagnetic pump. It is shown that for a particular flow coupler geometry, the total efficiency and the pressure gradients through the pump and generator depend on two parameters - the Hartmann number and the ratio of the pump flow rate to generator flow rate. Thus, for a fixed Hartmann number the efficiency depends only on the flow ratio. However, for a fixed pressure rise through the pump it is shown that the efficiency depends only on the Hartmann number. Nomographs showing the operating characteristics and critical design points are presented. Example calculations for a full-size unit, suitable for use in a liquid-metal cooled fast breeder reactor, are also discussed using the design nomographs.
Using the operator approach we reexamine the two-dimensional model describing a massive Fermi field interacting via derivative couplings with two massless Bose fields, one scalar and the other pseudoscalar. Performing a canonical transformation on the Bose field algebra, the Fermi field operator is written in terms of the Mandelstam soliton operator and the derivative-coupling (DC) model is mapped into the massive Thirring model with two vector-current-scalar-derivative interactions (Schroer-Thirring model). The DC model with massless fermions can be mapped into the massless Rothe-Stamatescu model with a Thirring interaction (massless Rothe-Stamatescu-Thirring model). Within the present approach the weak equivalence between the fermionic sector of the DC model and the massive Thirring model is exhibited compactly.
A flowing carbon dioxide laser was operated at low pressures up to 4 torr. Excitation of the laser was provided using various combinations of direct current (DC), pulsed microwave, and continuous wave (CW) microwave excitation. The microwaves were in the 2.45 GHz band and were coupled into the gas using a slow-wave interdigital transmission line. Laser output of 25 milliwatts (mw) was achieved using a DC discharge only. A combination of a DC discharge and pulsed microwaves doubled the output and resulted in some modulation. Changing the laser gas mixture and pulsed microwave field characteristics allowed some flexibility in the modulation. Lasing was not achieved with excitation from the CW microwaves alone due to the formation of localized discharges. Using pulsed microwaves to sustain the discharge and CW microwaves to pump the laser, a quasi-CW output of 55 mw was achieved.
Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends on the steel yoke dimensions. The detector sensitivity is equal to 1 Gauss/mm for ...
Abstract In response to growing consumer concerns, developed-country governments have reduced permissible pesticide residue levels in food. Many food retailers have developed even more stringent private food safety protocols relating to pesticide use, storage and disposal and passed them on to their suppliers. Exporters in developing countries enforce these developed-country pesticide standards (DC-PS) by subjecting farmers to close monitoring. This study explores the effects of enforcing compliance with DC-PS on smallholder farmers' pesticide-related health costs. Results suggest that enforcing DC-PS encourages farmers to use protection that lowers pesticide-induced morbidity, hence reducing farmers' health costs from pesticide exposure. The study concludes that there are health benefits ...
The feasibility of immobilizing simulated radioactive slurry (SRS) by alkali-activated slag---clay minerals composite cement (AASCM) was studied under the experimental conditions. The results show that the dosage of SRS and water cement ratio (W/C) have significant effect on the flowability of the mixture of AASCM and SRS. The more dosage of SRS, the lower flowability. When cement/sand ratio is 1: 1 and W/C is 0.45, the flowability of the mixture meets the case of solidification engineering and the compressive strength of the waste forms containing 20% SRS meets the needs of GB 14569.1-93. The setting time of the mixture of AASCM and SRS is highly dependent on temperature while sorts of anions have little influence on it. The application of AASCM is suitable below 20 degree C. The leaching resistance of AASCM based waste forms is superior to that of OPC based waste forms. The control of the forms to Sr2+ is stronger than that to Cs+. Silicon fume can improve ...
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 control group were within ...
The diverse microenvironments of foods, changing with processing and preservation, might provide conditions that would enhance the growth of microorganisms which are the principal cause of spoilage, off-odor and unpleasant flavor in foods. Radiation is a potential process which may provide a product with far superior microbial quality for food preservation, by reduction of microbial population; elimination of food-borne pathogens; extension of shelf-life; and reduction of spoilage. The aim of irradiation at low dose level is to eliminate certain microorganisms, especially spoilage types and those of public health significance. But, the radurization dose allows the outgrowth of radioresistant bacteria. Certain strains of Moraxella-Acinetobacter (M-A) groups have been recognized as radioresistant bacteria (Welch and Maxcy, 1975), which may have gone unnoticed by food microbiologists, since these bacteria have not been associated with problems and are present in ...
The rice blast resistance (R) gene Pi-ta mediates gene-for-gene resistance against strains of the fungus Magnaporthe grisea that express avirulent...Full Text Available
Objective: To investigate the mechanism of carbapenem resistance and the occurrence of plasmid-mediated quinolone resistance determinants qnr and aac(6′)-Ib-cr...Full Text Available
The emergence of bacterial antibiotic resistance is a growing problem, yet the variables that influence the rate of emergence of resistance are not well understood. In a microfluidic device designed to mimic naturally occurring bacterial niches, resistance of Escherichia coli to the antibiotic ciprofloxacin developed within 10 hours. Resistance emerged with as few as 100 bacteria in the initial inoculation. Whole-genome sequencing of the resistant organisms revealed that four functional single-nucleotide polymorphisms attained fixation. Knowledge about the rapid emergence of antibiotic resistance in the heterogeneous conditions within the mammalian body may be helpful in understanding the emergence of drug resistance during cancer chemotherapy. PMID:21940899
Xenorhabdus is a major insect pathogen symbiotically associated with nematodes of the family Steinernematidae. This motile bacterium displays swarming behavior on suitable media, but...Full Text Available
Folder Display Clocks Folder TWSTT Folder Loran-C Folder Telephone Time Folder NTP Info Web-Based Time Synchronization Web time displays from the USNO Master Clock, Washington, DC...
Dolores Beasley Headquarters, Washington, DC July 19, 2000 (Phone: 202/358- 1753) Bill Steigerwald Goddard Space Flight Center, Greenbelt, MD (Phone: ...
Overview Package  Class Use Tree Deprecated Index Help  PREV CLASS  NEXT CLASS FRAMES   NO FRAMES SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD gov.nih.nci.dc.database Class SearchCriteria java.lang.Object |
The scope of our problems with nuclear waste management is outlined. Present and future inventories of nuclear wastes are assessed for risk. A discussion of what is presently being done to solve waste management problems and what might be done in the future are presented. (DC)
Human bone marrow mesenchymal stem cells (BM-MSC) are multipotent progenitor cells that have transient immunomodulatory properties on Natural Killer (NK) cells, Dendritic Cells (DC), and T cells. This...Full Text Available
The application of HVDC system to the trunk power supply system requires the transmission of DC power as much as possible to improve the stability of the whole AC/DC system. To meet this requirement, continued pulse system, which keeps sending a DC current even when an AC voltage lowers remarkably, has been used. The stability is much more improved by adding damping control which modulates converter active and/or reactive power. In order to make full use of such control effects, it is important that the HVDC system maintains stable operation during faults and reclosing of the AC system. In particular, it is necessary to prevent a repetitive commutation failure following the unbalanced AC transmission line faults. In this paper, the cause of the repetitive commutation failure is discussed by using the AC-DC power system simulator developed by CRIEPI. Based on the analytical result, a stabilization ...
... and mean rainfall rates, Rm, in the liquid hydrometeor layers using the .... large latitudinal movement of cirrus cloud cover with the changing seasons. ... We study the statistical distribution of PSCs by particle composition using .... the high resolution Cloud Particle Imager (CPI) and standard PMS 2D-C and ...
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high {Tc} superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high T_c superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high [Tc] superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper presents the analysis and novel hybrid controller design for an interleaved 2-quadrant switched capacitor (SC) bidirectional DC/DC converter for a hybrid electric vehicle (HEV) dual energy storage system. The designed novel control strategy enables simpler dynamics compared to a standard buck converter with input filter, good regulation capability, low EMI, lower source current ripple, ease of control, and continuous input current waveform in both buck as well as boost modes of operation.
It is shown that the direct Fourier synthesization of light beams allows one to create polarity-asymmetric waves, which are able, in the process of nonlinear interaction with a medium, to break its inversion symmetry. As a result, these "polar" waves may show the effect of optical rectification in nonlinear centrosymmetric media by generating light-induced dc electric polarization. At the same time, the waves of this type, due to their unusual symmetry properties, can be used for detecting the direction and sign of a dc electric field applied to the medium. The prospects of application of polar waves to data recording and processing are discussed.
This work presents results of investigations on d.c. glow discharge nitriding of #alpha#+#beta# Ti-6Al-4V titanium alloy. The treatment was performed at 843 K in nitrogen-hydrogen atmosphere, pressure 300 Pa. Special attention was paid to nitriding mechanism and determination of the role of ion bombarding in nitriding process of titanium alloys. Produced as a result of d.c. plasma nitriding surface layers were subjected to macroscopic observations, microstructure studies, microhardness testing and X-ray analysis. (author)
Studies were made on different types of packaging materials used for packing dried fish in the Philippines with a view to finding a suitable packaging material for irradiated dried fish. Among these packaging materials (polyethylene, cello/polyethylene, polyester/polyethylene, Kraft paper, polypropylene and interwoven polypropylene sacks), polyester/polyethylene laminate was the most resistant material against penetration by Dermestes carnivorous. No insect damage occurred on the dried fish packed in interwoven polypropylene lined with polyester/polyethylene laminate. The cost per sack of such packaging material having a capacity of 50-80 kg is US$ 0.50. The sack lined with polyester/polyethylene proved to be durable for surface transportation from Bacolod City to Manila (approx. 360 miles). Radiation treatment at 225 krad was effective against bacterial contamination but not effective in inhibiting mould growth. Raw fish soaked in 25% salt for ...
This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted polymers obtained by ...
Little clinical evidence has been provided to show the minimization of radiationresistance of tumors using high linear energy transfer radiation. We therefore investigated the radiobiological and molecular pathological aspects of carbon beam therapy. A total of 27 patients with squamous cell carcinoma (SCC) of the cervix were treated using a carbon beam and 50 control patients with SCC of the cervix using a photon beam. The expression of Ki-67, p53, and p27 proteins before radiotherapy and 5 and 15 days after therapy initiation were investigated using immunohistochemistry. Similar changes were observed in Ki-67 labeling index (LI) and p53 LI during carbon and photon beam therapies. However, for carbon beam therapy, the mean p27 LI significantly decreased from 25.2% before treatment to 18.6% on the 5th day after treatment initiation, followed by a significant increase to 36.1% on the 15th day. In contrast, for photon beam ...
The thermal behaviour of 21 proteinaceous l-amino acids either as pristine samples and also as radiolyzed (3.2 MGy) samples was studied with the differential scanning calorimeter. The onset and peak melting point as well as the melting enthalpy of all samples before and after the radiation treatment was measured and reported. The residual amount of each amino acid survived to the radiation dose of 3.2 MGy (N_#gamma#) was measured from the melting enthalpies before and after radiolysis and hence the radiationresistance of each amino acid has been determined. The radiolysis causes a systematic reduction of the melting enthalpy and a shift of the onset and peak melting point to lower values. It is shown that N_#gamma# does not correlate with the melting points of the amino acids but shows a correlation with the entity of the shift of the melting point peaks occurred after radiolysis. Such correlation ...
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...
The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI{sub 2}) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10{sup 10} p/cm{sup 2} and significant bulk leakage after 10{sup 12} p/cm{sup 2}. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5 {times} 10{sup 9} p/cm{sup 2} in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from moderated fission spectrum of neutrons after fluences up to 10{sup 10} n/cm{sup 2}, although activation was evident. Exposures of CZT to 5 MeV alpha particle at fluences up to 1.5 {times} 10{sup 10} {alpha}/cm{sup 2} produced a near linear decrease in peak position with fluence and increases in FWHM beginning at about 7.5 ...
Oxide superconducting thin films were irradiated with X-rays and ultra-violet (UV) light, and induced radiation effects on electrical and chemical properties were examined by transport measurement, X-ray diffraction analysis (XRD), diamagnetization measurement and X-ray photoemission spectroscopy (XPS). After irradiation for ErBa_2Cu_3O_x films with X-rays emitted from a Rh tube for 100 hours, superconductivity was remarkably damaged, destroying the zero-resistance state. The UV-light irradiation for Bi_2Sr_2CaCu_2O_x films was performed in He gas of about 500 Pa with a low pressure mercury lamp. The superconductivity was gradually degraded with the UV irradiation time up to 70 minutes. In both cases, adequate oxygen-annealing treatments restored superconductivity. The X-ray photoemission spectra showed that the mean Cu valence of the films was decreased approximately from +2 to +1 by the irradiation. From these results we can find that ...
In the context of the research project, the physical basis of the direct decoupling of highly concentrated solar radiation in materials without the detour via absorbing heat exchanger walls was examined. Also, the first chemical processes suitable for the effective long-term storage of solar energy were analysed, relevant experiments were carried out and the necessary receiver techniques for high temperature applications were provided. The principle of direct coupling was examined on fluidized beds on the one hand and on cavity receivers, on the other hand. The contribution shows the results achieved in detail. It is recorded that first processes for storing solar energy in chemical reactions were able to be examined. Alkaline earth hydroxides accommodated in ceramic honeycomb structures seem to be possible as stores for medium temperature ranges around 500deg C. Investigations on receiver structure materials are also making progress. Highly transparent, high ...
Radioadapted chicken embryo cells (X-irradiation in ovo with 10 cGy at the 14th day of development with priming periods of 24 h) were treated in vitro by challenge doses of 14 different DNA- and/or chromatin-interactive agents, including X-rays. A decrease in the cellular damage, as measured by scheduled DNA synthesis, was only observed with X-irradiation. Sedimentation of nucleoids as well as viscosity of alkaline lysates from ethidium bromide (0.35-400 {mu}g/ml)-, vovobiocin (125-1800 {mu}g/ml)-, and hyperthermia (30 min at 43 and 45 )-treated cells suggest a higher tendency of radioadapted cells to undergo positive DNA supercoiling. When DNA from adapted and non-adapted chicken embryo cells was used as substrate, neither its digestion by DNase I nor the inhibition of DNase I activity by various DNA-interactive agents was changed in primed cells. From the previous investigations as well as from the present results it is concluded that an increase of tightening of protein-DNA ...
Continuous metallic glass ribbons were produced by mejans of liquid-quenching at rates >10/sup 50/C/s. The ribbons, typically 30 ..mu..m thick and 1 to 2 mm wide, were determined to be glassy by X-ray diffraction (XRD) employing CuK..cap alpha.. and MoK..cap alpha.. radiation. Mechanical properties of the as-quenched product were determined by measurements of hardness, tensile strength and Young's modulus. The Vicker's diamond pyramid microhardness (H/sub V/) was measured on epoxy mounted samples using a Lietz Miniload instrument with a 100 g load. Tensile tests were conducted in an Instron machine using specimens which were hand-polished to produce smooth, parallel sides. Young's modulus (E) is given by the relationship rho V/sub E/sup 2//. V/sub E/, the velocity of extensional mode waves, was measured by the pulse-echo technique using a Panametrics Intervalometer and glass density, rho, was obtained by the liquid immersion method. ...
The LHCb experiment that is being settled in CERN is dedicated to the study of CP violation and rare decays in the field of beauty hadrons. The phenomenological background necessary to an adequate understanding of the physics of flavor is presented in the first chapter, it is shown how the flavordynamics can open the way to new physics. The second chapter is dedicated to a brief presentation of the LHCb detector. Two aspects of the design of the muon trigger are more detailed: the radiationresistance of the opto-electronic transmitters and the simulated performances of the trigger. The third chapter reviews the tasks linked to the tagging of the savors of B mesons which will be an important step in all the experiments made at LHCb. The recent progress in heavy savor physics as well as the expected contribution of LHCb in this field are presented in the fourth chapter, especially the search for new physics in penguin diagrams b {yields} s.
Alloy HT-9 is being used for both duct and cladding applications in advanced liquid-metal reactor (LMR) experiments. This tempered martensitic steel was selected for use as an LMR core component material primarily because of its excellent resistance to radiation-induced swelling. Experiments conducted in the Fast Flux Test Facility (FFTF) at 410 degree C and exposures in the range of 150 to 175 displacements per atom (dpa) have shown that Ht-9 exhibits only a 0.2 to 0.3% increase in volume. Cold-worked austenitic steels exhibit volumetric increases of 20 to 30% at 410 degree C, Alloy HT-9 is being used for a series of fuel pin experiments in the FFTF, and these tests have achieved a burnup of 175 MWd/kg metal and a fluence of 25 x 10"2"2 n/cm"2 (E > 0.1 MeV) without fuel pin breach. The high confidence placed in HT-9 is based on a wide series of in- and ex-reactor experiments. Test results for these experiments are summarized in this paper.
The survival time of golden hamsters (Mesocricetus auratus) after whole-body "6"0Co-#gamma#-irradiation in the range of 600 to 200 000 rad was investigated. The two plateaus of the dose-survival curve which correspond to bone marrow and gastrointestinal death are similar to those of other species such as mice, rats and mongolian gerbils. A new plateau occurring 40-57 hours after doses of 30 000-60 000 rad, where there is a little reduction in survival time, has been found. It is in addition to the well recognized central nervous system (CNS) syndrome. This plateau is observed only in golden hamsters, presumably because of their relatively high resistance to CNS syndrome. Experiments involving partial body irradiation of the animals indicate that the target is in the cephalic one-third of abdomen. The new segment may well indicate a new type of acute somatic radiation injury different from the well known bone marrow, gastrointestinal and CNS ...
The operation of nuclear processing facilities and defense-related nuclear activities has resulted in contamination of near-surface and deep-subsurface sediments with both radionuclides and metals. The presence of mixed inorganic contaminants may result in undetectable microbial populations or microbial populations that are different from those present in uncontaminated sediments. To determine the impact of mixed radionuclide and metal contaminants on sediment microbial communities, we sampled a processing pond that was used from 1948 to 1975 for the disposal of radioactive and metal-contaminated wastewaters from laboratories and nuclear fuel fabrication facilities on the Hanford Site in Washington State. Because the Hanford Site is located in a semiarid environment with average rainfall of 159 mm/year, the pond dried and a settling basin remained after wastewater input into the pond ceased in 1975. This processing pond basin offered a unique opportunity to obtain near-surface ...
Cathodic arc deposition is an established and industrially applied technique for the formation of nitrides (e.g. TiN); it can also be used for metal oxide thin film formation. A cathodic arc plasma source with the desired cathode material is operated in an oxygen atmosphere of appropriate pressure, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on accelerator components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}-Y{sub ...
A critical review of the literature revealed no experiments on uranyl ion transfer from an aqueous to a tributyl phosphate phase which positively measured the kinetics of the chemical reaction at the interphase. Drawing isorhythmic lines on a three component diagram gives a complex correlation for the compaction of three sizes of glass beads. Neither the use of thoria sols nor high feed solution concentrations of thorium nitrate gave any significant increase in mean particle diameters over those obtained from nitrate solutions of lower concentrations in flame denitration. A hydraulic film resistance has been detected in the anion exchange of uranyl sulfate into Dowex 2lK, and chloride elution was found to give a higher apparent uranium diffusion coefficient than nitrate elution. The rate of dissolution of mixed thorium-uranium oxides was determined as a function of the per cent of mixed oxides dissolved. Mixing in tanks packed with ...
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).
Bloodstream infection by highly antibiotic-resistant bacteria, such as vancomycin-resistant Enterococcus (VRE), is a growing clinical problem that increasingly defies medical intervention....Full Text Available
Twelve Salmonella typhimurium strains resistant to broad-spectrum cephalosporins were isolated from cases of gastroenteritis during 1996 to 1998 in Russia, Hungary, and Greece. Resistance...Full Text Available
Antimicrobial resistance is an emerging problem with Pseudomonas aeruginosa. This study determined risk factors for the recovery of piperacillin-tazobactam-resistant P. aeruginosa...Full Text Available
To determine who resists sexual assault and what happens, data were examined from a probability sample of 3,132 adult community residents of Los Angeles, California. Seventy-five per cent of the respondents...Full Text Available
Purpose of reviewPhysicians, researchers and policy makers must understand the myriad consequences of multidrug and extensively drug-resistant tuberculosis (TB) within...Full Text Available
Pyrethroid insecticides have been extensively used in China and worldwide for public health pest control. Accurate resistance monitoring is essential to guide the rational use of insecticides and resistance...Full Text Available
The direct detection of pyrazinamide resistance in Mycobacterium tuberculosis is sufficiently difficult that many laboratories do not attempt it. Most pyrazinamide resistance is caused...Full Text Available
Antimicrobial resistance is an emerging problem among nosocomial bacteria. Risk factors for the recovery of ceftriaxone-resistant (CRCF) or -susceptible (CSCF) Citrobacter freundii...Full Text Available
Longitudinal electrical resistances have been measured on 2-centimeter segments of corn (Zea mays L.) roots, cut at varying distances from the root apex. The segment resistances vary...Full Text Available
In methicillin-resistant Staphylococcus aureus, the methicillin resistance gene mecA is localized within a large chromosomal region which is absent in the methicillin-susceptible...Full Text Available
The antibiotic resistance patterns of gram-negative fecal bacteria from pigs in three herds with different histories of antibiotic exposure were examined. In general, smaller proportions of antibiotic-resistant...Full Text Available
...visible damage. (k) Corrosion resistance. Each metal part of a...evidence of salt-spray corrosion resistance equal to or greater than...sample of test metal must show corrosion resistance equal to or better than...
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)
The author reviews the growth of the insecticide-resistance problem throughout the world during the period between July 1956 and November 1957, and the developments in research on the subject during...Full Text Available
The development of several DDT-resistant strains of Anopheles atroparvus is described. They were selected by larval treatment only (RL), selection of larval and adult females (RLAF),...Full Text Available
Summary: The increasing emergence of antimicrobial-resistant organisms, especially methicillin-resistant Staphylococcus aureus (MRSA), has resulted in the increased...Full Text Available
In order to provide a rational basis for the development of new insecticides, a thorough understanding of resistance mechanisms is necessary and this presupposes a detailed knowledge of the normal...Full Text Available
A strain of Pseudomonas syringae was recently identified as the cause of a new foliar blight of impatiens. The bacterium was resistant to copper compounds, which are used on a variety...Full Text Available
Individual strains of the plant pathogenic bacterium Pseudomonas syringae vary in their ability to produce toxins, nucleate ice, and resist antimicrobial compounds. These phenotypes...Full Text Available
In this work we conducted both in vitro and in vivo experiments to examine the development and mechanisms of erythromycin (Ery) resistance in Campylobacter jejuni and Campylobacter...Full Text Available
The mechanism of resistance to DDT was investigated in Culex mosquitos to ascertain whether it was associated with detoxication to DDE as in houseflies and Aedes aegypti....Full Text Available
We compared the incidence of nasopharyngeal colonization by Streptococcus pneumoniae, the serotypes causing mucosal and invasive diseases, and the antibiotic resistance of these strains...Full Text Available
Staphylococcus aureus isolates and 2 USA300 ATCC type strains for susceptibility to bacitracin and neomycin contained in over-the-counter antibacterial ointments. Resistance to...
Introduction:The purpose of this study was to utilize an in vitro biofilm model of subgingival plaque to investigate resistances in subgingival biofilm...Full Text Available
S-Adenosylmethionine decarboxylase (AdoMetDC) is a critical enzyme in the polyamine biosynthetic pathway and depends on a pyruvoyl group for the decarboxylation process. The crystal structures of the enzyme with various inhibitors at the active site have shown that the adenine base of the ligands adopts an unusual syn conformation when bound to the enzyme. To determine whether compounds that favor the syn conformation in solution would be more potent AdoMetDC inhibitors, several series of AdoMet substrate analogues with a variety of substituents at the 8-position of adenine were synthesized and analyzed for their ability to inhibit hAdoMetDC. The biochemical analysis indicated that an 8-methyl substituent resulted in more potent inhibitors, yet most other 8-substitutions provided no benefit over the parent compound. To understand these results, we used computational modeling and X-ray crystallography to study C{sup ...
It Peripheral blood progenitor enriched CD34+ cells (PBPC) are rather often used as stem cell background in cancer patients following high dose therapy. Keeping in mind that precursor dendritic cells (DCs) originate from haematopoietic progenitor cells, purified CD34+ cells might also serve as starting cells for ex-vivo production of DC. The aim of the present study is to develop a clinical grade procedure for ex-vivo production of DC derived from enriched CD34+ cells. Various concentrations of CD34+ cells were grown in gas-permeable Teflon bags with different serum-free and serum-containing media supplemented with GM-CSF, IL-4, TNF-a, SCF, Flt-3L and INF-a. Serum-free CellGroSCGM medium for 7 days followed by CellGroDC medium in 7 days gave equal results as serum-containing medium. Follow...
Benzene molecules , present in the proto-planetary nebula CRL 618, are ionized and dissociated by ultraviolet (UV) and X-ray photons originated from the hot central star and by its fast wind. Ionic species and free radicals produced by these processes can lead to the formation of new organic molecules. The aim of this work is to study the photoionization and photodissociation processes of the benzene molecule, using synchrotron radiation and time-of-flight mass spectrometry. Mass spectra were recorded at different energies corresponding to the vacuum UV (21.21 eV) and soft X-ray (282-310 eV) spectral regions. The production of ions from the benzene dissociative photoionization is here quantified, indicating that C_6H_6 is more efficiently fragmented by soft X-ray than UV radiation, where 50% of the ionized benzene molecules survive to UV dissociation while only about 4% resist to C-rays. Partial ion yields of H and small ...
Direct current motors are used in photovoltaic systems. Important characteristics of electric motors are the starting to rated current and the torque ratios. These ratios are dictated by the size of the solar cell array and are different for the various dc motor types. The paper deals with the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, separately, series and shunt excited motors when powered by solar cells for the two cases: where (1) the system includes a maximum-power-point-tracker (MPPT) and (2) without an MPPT. Comparing these two cases, one gets a torque magnification of about 3 for the permanent magnet motor and about 7 for other motor types at rated design insolation. The calculation of the torques may assist the PV system designer to determine the advantage of including an MPPT in the system as far as the starting characteristics of the dc motors are concerned.
This paper addresses the stability aspects of several successful dc superconducting magnets such as large bubble chamber magnets, and magnets for the Mirror Fusion Test Facility and MHD Research Facility. Specifically, it will cover Argonne National Laboratory 12-Foot Bubble Chamber magnets, the 15-foot Bubble Chamber magnets at Fermi National Laboratory, the MFTF-B Magnet System at Lawrence Livermore National Laboratory, the U-25B Bypass MHD Magnet, and the CFFF Superconducting MHD magnet built by Argonne National Laboratory. All of these magnets are cooled in pool-boiling mode. Magnet design is briefly reviewed. Discussed in detail are the adopted stability critera, analyses of stability and disturbance, stability simulation, and the final results of magnet performance and the observed coil disturbances.
Efforts concentrated on updating of the Rockwell reference concept, definition of new system options, studies of special emphasis topics, further definition of the transportation system, and further program definition. The Rockwell reference satellite concept has a gallium arsenide (GaAs) solar cell array having flat concentrators with an effective concentration ratio of 1.83at end of life. Alternatives to this concept includes solid state power amplifiers or magnetrons for dc/RF conversion and multibandgap solar cells for solar to dc energy conversion. Two solid state concepts were studied. It was determined that the magnetron approach was the lowest mass and cost system.
This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N{sub 2} : H{sub 2}) and pulsed ratio (pulse on/off time ratio)
This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N_2 : H_2) and pulsed ratio (pulse on/off time ratio).
This paper describes the dielectric and accelerated aging tests on prototype {plus minus}500 kV dc oil-filled self-contained cables. The extensive test program was required to evaluate the High-Voltage cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper relates the main elements of the test program. It describes the required insulation levels, the characteristics of the cables supplied by three different manufacturers, as well as the cables' installation for the type tests and accelerated aging tests. Details of the test program and procedures followed to carry out the tests are given. Findings of the tests are also reported.
A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.
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)
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 high temperature abrasive wear resistant of the composites with different Al{sub 2}O{sub 3} volume fractions, particle coating and size were investigated and the failure action of composites under different conditions at high temperature was analyzed. The results showed that the high temperature abrasive wear resistant of composite with Ni coating and wide size and 39% volume fraction of particle is the best among all composites examined. (orig.)
The temperature rise induced by shock compression of polymethyl methacrylate (PMMA) was determined from measurements of the electrical resistivity of embedded copper foils. The temperature of the copper was determined from the observed foil resistance and known values of the change in copper resistivity with temperature and shock compression. Temperature values obtained over a stress range from 0.9 to 6.0 GPa are in good agreement with thermocouple measurements reported previously.
We present the first results from tests of a MICROMEGAS detector manufactured using the so-called "bulk" technology and having a resistive cathode mesh instead of the conventional metallic one. This detector operates as usual MICROMEGAS, but in the case of sparks, which may appear at high gas gains, the resistive mesh reduces their current and makes the sparks harmless. This approach could be complementary to the ongoing efforts of various groups to develop spark-protected MICROMEGAS with resistive anode planes.
We quantified the resistance levels of transgenic rice plants, expressing Myxococcus xanthus protoporphyrinogen oxidase (PROTOX) in chloroplasts and mitochondria, to PROTOX inhibitors, acifluorfen, oxyfluorfen, carfentrazone-ethyl, and oxadiazon. We also determined whether active oxygen species-scavenging enzymes are involved in the resistance mechanism of transgenic rice. The transgenic rice line M4 was about >200-fold more resistant to oxyfluorfen than the wild-type (WT). M4 was also resistant to acifluorfen, carfentrazone-ethyl, and oxadiazon, but did not show multiple resistance to imazapyr and paraquat, which have different target sites. Acifluorfen, oxyfluorfen, carfentrazone-ethyl, and oxadiazon reduced the chlorophyll content in leaves of WT, but had minimal or no effect on M4. The...
Data processing method was studied for mise-a-la-masse survey. Mise-a-la-masse method using wells as current sources measures resultant ground surface potential difference, and detects underground local resistivity anomaly. To extract resistivity anomaly largely different from surroundings, the anomaly is extracted as difference between the estimated value of regular resistivity structure (background) and potential difference or apparent resistivity. The following three approximations were attempted to estimate the background: the theoretical equation assuming isotropic homogeneous resistivity structure, that assuming horizontal multi-layered structure and the exponential function of distance from linear electrode for apparent resistivity, and these were compared with each other by numerical model experiment. The data processing method which determines the ...
Results of researches on nitriding process of EJ961 steel are presented in this work. This steel was subjected to nitriding both on the cathode and on the isolated from cathode and anode substrate, that is at so called potential of glow discharged plasma. Nitriding processes were performed using device for glow discharge treatments with cooled anode. (author)
Pseudomonas syringae is a gram-negative bacterial plant pathogen that is dependent on a type III protein secretion system (TTSS) and the effector proteins it translocates into plant...Full Text Available
A community health survey of 438 individuals was taken to detect health problems related to high voltage electrical transmission among an adjacent residential population. Results revealed no significant or consistent relationships between exposure to a high voltage DC power line and the perceived health problems that were measured. The sample was not, however, large enough to draw statistically significant conclusions regarding possible health effects with a very low incidence.
Overview Package  Class Use Tree Deprecated Index Help  PREV CLASS  NEXT CLASS FRAMES   NO FRAMES SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD gov.nih.nci.dc.builder Interface SAXFilter All Superinterfaces: org.xml.sax.XMLFilter,
Overview Package  Class Use Tree Deprecated Index Help  PREV CLASS  NEXT CLASS FRAMES   NO FRAMES SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD gov.nih.nci.dc.bean Class ImageIDParseBean java.lang.Object | +--java.util.Dictionary
This report, entitled Combustion Engineering Standard Safety Analysis Report -- Design Certification (CESSAR-DC), has been prepared in support of the industry effort to standardize nuclear plant designs. These volumes describe the Combustion Engineering, Inc. System 80{sup +}{trademark} Standard Design. This volume 9 discusses Electric Power and Auxiliary Systems.
This report, entitled Combustion Engineering Standard Safety Analysis Report -- Design Certification (CESSAR-DC), has been prepared in support of the industry effort to standardize nuclear plant designs. These volumes describe the Combustion Engineering, Inc. System 80{sup +}{trademark} Standard Design. This volume 8 provides a description of instrumentation and controls.
...Resort and Convention Center, National Harbor, Maryland, USA September 18-20, 2011 XX HELSINKI DRUG RESEARCH CONGRESS Helsinki, Finland October 23-27, 2011 2011 AAPS Annual Meeting and Exposition Washington Convention Center Washington, DC June 26-29 2012 10th International Symposium on Pharmaceutical Sciences Ankara, Turkey Printer-friendly version Home | Elsevier ...
In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed ...
These documents defines the interconnection France-England rules for the 2000 MW DC submarine cable directly linking the transmission networks of England and Wales and France. Rights to use Interconnector capacity from 1 April 2001 are to be offered through competitive tenders and auctions, full details of which are set out in the Rules. The contract and a guide to the application form are provided. (A.L.B.)
... Research Center, Washington DC May 23 BBC NEws: US used Nuclear Weapons in Afghanistan Jalalabad: New reference levels based on recent samples show uranium levels 45 times normal. New bioassay studies identify uranium internal contamination in Spin Gar (Tora Bora) area and the City ...
... Operational aspects of fiscal policy making in oil-producing countries , in J. Davis, R. Ossowski and A. Fedelino (...), Fiscal Policy Formulation and Implementation in Oil-Producing Countries , International Monetary Fund, Washington, D.C. Barro, R. (...
Electric cars run silently and produce no exhaust fumes. In cooperation with other companies BBC has developed a compact drive system for the VW Golf comprising a battery-powered separately excited DC motor, transmission, control system and setpoint devices. With a range of 57 km and a top speed of 90 km/h, the electric Golf lends itself well to city driving.
The use of an SCR-controlled power system on an offshore drilling rig has lead to an increased acceptance of high technology equipment. Such equipment increases drilling productivity, reduces maintenance, and improves reliability. Most new rigs now have AC squirrel cage motors, brushless AC generators, silicon controlled rectifiers, DC motors, and swtichgear and motor starters. Several opportunities for cost reductions in SCR systems, such as improving the power factor, are studied in this paper.
Experimental results are presented on the quasi-statistic polarization reversal and on the effect of high dc electric field on the behaviour of LiNH_4SO_4 and LiND_4SO_4 monocrystals, namely in the vicinity of the II-III phase transformation.
GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to distribute ion damage over a larger area, ...
Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck (Piperaceae) is a medicinal plant traditionally used in Brazil to treat infectious diseases. The extracts obtained from the leaves of P. regnellii were investigated for their antifungal activities against the yeasts Candida albicans, C. krusei, C. parapsilosis, and C. tropicalis. The EtOAc extract presented gnificant activity against Candida albicans with MIC at 125 {mu}g mL{sup -1}, and a moderate activity against both C. krusei and C. parapsilosis with MIC at 500 {mu}g mL{sup -1}. Candida tropicalis was not inhibited by this extract at concentrations as high as 1000 {mu}g mL{sup -1}. Based on these findings, the EtOAc extract was fractionated by silica gel column chromatography into nine fractions. The hexane and CHCl{sub 3} fractions showed varied levels of antifungal activity against all test yeasts. Further column chromatography separation of the hexane fraction afforded the pure ...
A physical explanation is given for the positive differential voltage-current characteristic seen at low current in weakly ionized, low-pressure positive column discharges in argon/mercury gas mixtures. {copyright} {ital 1996 The American Physical Society.}
During the last several years, audible noise produced by high voltage transmission lines in corona has emerged as an important design consideration. In this same time frame a number of different methods for calculating audible noise levels have been proposed. The methods currently available, for both ac and dc lines, are described in this paper and are compared through application to practical line geometries for which data from long-term measurements are available.
This project is a follow-up of the first development of a 500 kV HVDC airblast circuit breaker (EPRI project 1507-3). The objective was to increase the current interrupting capability from 2200 A to 4000 A and shorten its fault clearing time. A high current 500 kV HVDC circuit breaker has been built using the passive commutation circuit. The breaker is modular in construction and can be designed for a wide variety of system conditions. More than 400 current interruptions were carried out successfully. Tests have shown that this circuit breaker is capable of interrupting more than 4000 A dc. Practical breakers with current interrupting capability of even 5500 A dc could be built. The circuit breaker operation and the fault-clearing process can be materially speeded up if the trip signal is given as soon as the fault is detected and without waiting for the current levels to come down in response to converter control action. The new ...
Progress in four research areas on this project are summarized under the following topics: (1) Geminate charge pair recombination in hexane; (2) Fast current measurements resulting from excitation of charge transfer (CT) states; (3) Measurement of the dipole moment of excited states by DC conductivity; and (4) Charge separation at macroscopic interfaces between electron donor and acceptor solids. In a final section, personnel who have contributed to the project during the past budget period are described.
In this article, a continuous stabilization process was used to make flame resistant fibers from polyacrylonitrile (PAN) fibers. The effect of the stabilization time and the stretching process during the stabilization process on the physical properties and flammability of the resultant flame resistant fibers was studied. Increased drawing of PAN fibers during the continuous stabilization process was found to decrease the diameter and increase the tensile strength in the resultant flame resistant fibers. These fibers also had higher density. There were no absolute relationships seen between flame-resistance and the formation of stable ladder polymers, density, and oxygen content. ((orig.))
Recent data on resistance of modern corrosion-resistant austenitic-ferritic steels to different types of corrosion are generalized. It is shown that these steels are characterized by high resistance to general corrosion in acid, alkali, chloride and other solutions, are not inclined to intercrystalline, pitting and crevice corrosion and are noted for high resistance to corrosion cracking and corrosion fatigue. All this is combined with technological and economical effectiveness. It is advisible to use these steels instead of highly-alloyed and expensive steels and alloys in chemical, power and other industries. 59 refs.; 2 tabs.
Corrosion testings of model alloys, corresponding by chemical composition to simple and complex-alloyed #gamma#- and #gamma#'-phases of nickel heat-resistant alloys are conducted in sodium sulfate and chloride melts. It is ascertained that heat resistant nickel alloys containing over 50 % of hardening #gamma#'-phase, are subject to disastrous sulfide corrosion (SC). Resistance against SC alloys containing below 50 % of #gamma#'-phase is determined by the resistance of #gamma#-solid solution. 10 refs., 3 figs., 2 tabs.
Analyzing various SBLOCA with high pressure safety injection (HPSI) at VVER-440/213, we met a surprising phenomenon - a 'natural' circulation post SG heat transfer reversal. This is not usual, because normal natural circulation (NC) in primary circuit is connected with positive heat transfer at SG. If there is reverse heat transfer at SG (as soon as the break enthalpy outflow is sufficient for removal of reactor decay heat), it should obstruct any natural circulation. The question was, what is the driving force of this 'non-standard natural circulation'. After all we revealed that force - it is the density difference between the colder water in reactor downcomer (cold water from HPSI) and warmer water in inner reactor (lower plenum, core, upper plenum). This phenomenon could be confusing for operating personal, because there would be an opposite temperature difference at the loop than by normal natural circulation (under non-standard NC conditions ...
Analyzing various SBLOCA with high pressure safety injection (HPSI) at VVER-440/213, we met a surprising phenomenon - a 'natural' circulation post SG heat transfer reversal. This is not usual, because normal natural circulation (NC) in primary circuit is connected with positive heat transfer at SG. If there is reverse heat transfer at SG (as soon as the break enthalpy outflow is sufficient for removal of reactor decay heat), it should obstruct any natural circulation. The question was, what is the driving force of this 'non-standard natural circulation'. After all we revealed that force - it is the density difference between the colder water in reactor downcomer (cold water from HPSI) and warmer water in inner reactor (lower plenum, core, upper plenum). This phenomenon could be confusing for operating personal, because there would be an opposite temperature difference at the loop than by normal natural circulation (under non-standard NC conditions water is heated in SG so there is ...
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).
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 ...
... Radiation Protection Products and Equipment Find and compare a variety of radiation protection products and equipment on the world's largest environmental industry portal. View product ...
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 ...
Zirconium is a transition element located along with sister elements titanium and hafnium in Group IVB of the periodic table. It is grayish white metal, with a density somewhat less than carbon steel. Zirconium is the ninth most common metallic element in the earth's crust, and is more abundant than zinc, lead, nickel, or even copper. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis. It is resistant to most organic acids, such as formic, acetic, lactic, and oxalic acids. It also has a high resistance to localized forms of corrosion, such as pitting, crevice corrosion, and stress corrosion cracking. Its corrosion resistance is caused by the formation of a dense, tenaciously adherent, chemically inert oxide film on the surface. This oxide film protects the base metal from both chemical and mechanical attack at temperatures up to about 400 C (750 F). This article describes ...
The direct injection of steam into a water pool is a method of heat transfer used in many process industries. The amount of research in this area however is limited to the nuclear industry, with applications relating to reactor cooling systems. Electrical resistance tomography (ERT), a low cost, non-invasive and which has high temporal resolution characteristics, can be used as a visualization tool for the resistivity distribution for the steam injection into water pool such as IRWST. In this paper, three dimensional resistivity distribution of the process is obtained through ERT using iterative Gauss-Newton method. Numerical experiments are performed by assuming different resistive objects in the water pool. Numerical results show that ERT is successful in estimating the resistivity distribution for the injection of steam in the water pool
Globodera rostochiensis and Globodera pallida are parasitic root cyst nematodes of potato (PCN), which significantly reduce yield and quality. The genetics and available molecular markers should make resistance to nematodes an excellent candidate for marker assisted selection. The study presents results of testing the suitability of known molecular markers for detection of resistance in a set of cultivars. We revealed some inconsistencies in genealogical data of the cultivars and showed inconsistent usefulness in detecting resistant cultivars. The marker TG689 was identified in almost all cultivars resistant to G. rostochiensis and together with other markers was used for verifying the resistance in a group of breeding lines. The marker TG689 was the most effective. However, the efficiency...
BACKGROUND: Glyphosate resistance has been confirmed in 58 populations of Lolium rigidum (Gaud.), a major weed of crops in southern Australia. Extensive use of glyphosate in conjunction with minimal soil disturbance has been identified as high risk for resistance to that herbicide. Land managers need a simple method for rapid assessment of the risk of resistance occurring as a result of past and proposed future management practices. Modelled on risk assessment nomographs, a simple calculator for indicating the risk of evolved glyphosate resistance in L. rigidum is described.RESULTS: The calculator uses the generations since first use and the frequency of use of glyphosate in combination with historical cultivation levels as critical factors for determining the risk of glyphosate resistance...
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.
Three copper-based alloys, CDA 102 (oxygen-free, high-purity copper), CDA 613 (aluminum bronze), and CDA 715 (Cu-30Ni), are candidates for the fabrication of high-level radioactive-waste disposal containers. Waste will include spent fuel assemblies from reactors as well as borosilicate glass, and will be sent to the prospective repository site at Yucca Mountain in Nye County, Nevada. The decay of radionuclides will result in the generation of substantial heat and in fluxes of gamma radiation outside the containers. In this environment, container materials might degrade by atmospheric oxidation, general aqueous phase corrosion, localized corrosion (LC), and stress corrosion cracking (SCC). This volume is a critical survey of available data on pitting and crevice corrosion of the copper-based candidates. Pitting and crevice corrosion are two of the most common forms of LC of these materials. Data on the SCC of these alloys is surveyed in Volume 4. Pitting usually ...
Alloys of zirconium are widely used in various core components of power reactors. Nuclear assemblies require high degree of reliability and integrity for performing in radiation and corrosive atmosphere. The hostile environments of reactor core and inaccessibility for repairs make it mandatory to select only those joining techniques which produce not only superior quality but are also amenable to NDT methods and such other techniques which ensure acceptable performance. The author has worked on various types of welding of zirconium alloys for different applications. Modern techniques in electron beam (EB) welding, resistance welding, GTAW welding and laser welding have been developed for joining Zr alloys components for different types of reactors. Many of these have been standardized and successfully used in production. Several advancements have been made in the welding technologies towards achieving high productivity and increased reliability ...
The effects of the antioxidants, vitamin E, propyl gallate, 2-t-butyl-4-methoxy phenol (BHA), 2,6-di-t-butyl-4-methoxy phenol (BHT), nor-dihydroguaiaretic acid (NDGA) and diphenyl-p-phenylene diamine (DPPD) in concentrations ranging between 0.001 per cent and 0.1 per cent have been tested on lipid peroxide formation in synthetic diet mixtures containing herring oil (10 per cent) mixed with starch (90 per cent) irradiated with #gamma#-ray doses of 100 to 2000 krad. On a weight basis NDGA, DPPD, BHA and BHT were most effective and vitamin E and propyl gallate were least effective. An antioxidant concentration of 0.01 per cent normally protected against peroxide formation after a dose of 500 krad but if the dose was increased to 1000 or 2000 krad, much higher doses of antioxidant, up to 0.1 per cent, were required to give protection. Antioxidants prevented peroxide developing during post-irradiation storage even when added after irradiation. Antioxidants were partially or completely ...
Two mechanical design requirements are defined for the SSC Collider beam tube. First, the vacuum requirement (luminosity lifetime = 150 hrs). It requires the design of a pressure boundary within the cold mass vessel to provide a vacuum tunnel for the proton beam and to minimize the synchrotron radiation gas desorbtion with a suitable material. The Collider beam tube design is under an intensive activity to search for a material that will meet the luminosity requirement without a distributed pump or liner. Second is the tube wall`s resistivity requirement ({sigma}*t = 2E5 {Omega}{sup {minus}1}). For a 4.2 K beam tube the Cu thickness is 100 {mu}m (RRR=30,6.7 T, {sigma}=2E9{Omega}{sup {minus}1}m{sup {minus}1}). The copper yield strength is relatively low in comparison to steel and, therefore, the design of the steel layer is governed by the copper layer yield stress limit. A beam tube subjected to eddy current load in a quenching dipole requires ...
Two mechanical design requirements are defined for the SSC Collider beam tube. First, the vacuum requirement (luminosity lifetime = 150 hrs). It requires the design of a pressure boundary within the cold mass vessel to provide a vacuum tunnel for the proton beam and to minimize the synchrotron radiation gas desorbtion with a suitable material. The Collider beam tube design is under an intensive activity to search for a material that will meet the luminosity requirement without a distributed pump or liner. Second is the tube wall's resistivity requirement ([sigma]*t = 2E5 [Omega][sup [minus]1]). For a 4.2 K beam tube the Cu thickness is 100 [mu]m (RRR=30,6.7 T, [sigma]=2E9[Omega][sup [minus]1]m[sup [minus]1]). The copper yield strength is relatively low in comparison to steel and, therefore, the design of the steel layer is governed by the copper layer yield stress limit. A beam tube subjected to eddy current load in a quenching dipole ...
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physico-mechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl acrylate (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5 - 20 Mrad leads to radiolysis of the above copolymers, accompanied by destructive processes. Evidence of this is an increase in the ...
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physicomechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5-20 Mrad leads to radiolysis of the above copolymers, accompanied by destructive processes. Evidence of this is an increase in the ...
A unique feature of cyanobacteria genomes is the abundance of genes that code for hypothetical proteins containing tandem pentapeptide repeats approximately described by the consensus motif A(N/D)LXX. To date, the structures of two pentapeptide-repeat proteins (PRPs) have been determined, with the tandem pentapeptide-repeat sequences observed to adopt a novel type of right-handed quadrilateral ?-helix, or Rfr-fold, in both structures. One structure, Mycobacterium tuberculosis MfpA, is a 183-residue protein that contains 30 consecutive pentapeptide repeats and appears to offer antibiotic resistance by acting as a DNA mimic. The other structure, Cyanothece 51142 Rfr32, is a 167-residue protein that contains 21 consecutive pentapeptide repeats. The function of Rfr32, like the other 35 hypothetical PRPs identified in the genome of Cyanothece, is unknown. In an effort to understand the role of PRPs in cyanobacteria and to better characterize the structural properties of ...
A cryocondensation pump was designed for the baffle chamber of General Atomics DIII-D tokamak and will be installed in the fall of 1992. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long and located in the lower outer corner of the vacuum chamber of the machine. It consists of a 1 m{sup 2} liquid helium-cooled surface surrounded by a liquid nitrogen-cooled shield to limit the heat load on the helium-cooled surface. The liquid nitrogen-cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. A thermal enhancement coating was applied to the nitrogen shell to lower the maximum temperature of the shell. The coating is non-continuous to keep the toroidal electrical resistance high. The whole pump is supported off the water-cooled vacuum vessel wall. Supports for the ...
The properties of cast basalt and alumina are examined. The ways in which these materials have been used in applications in coal preparation plants, for example in bunker and pipe linings where abrasion and corrosion resistant materials are required, are discussed.
To make the surface composites with hard ceramics particles is an effective means for satisfying the request for the wear-resistance of the casting products. Covering casting is a general method for forming the composites by adding the adhesive into ceramics particles. However, due to the using of adhesive, pore and intermediate are easy to generate, and it is one of the reasons making the wear-resistance unstable. In the present study, it is attempted to form the wear-resistant composite layer by dispersing cast tungsten carbide (CTC) particles on the surface of wear-resistant 7 mass% Mn steel without using adhesives. Subsequently, the experiments on the wear-resistance of the obtained surface composites under several wear conditions are carried out. It is revealed by the results thereof that 7 mass% Mn steel surface composites with CTC particles have the ...
Transformed Drosophila Kc cell lines, resistant to methotrexate, an inhibitor of de novo purine and pyrimidine synthesis, have been obtained by calcium phosphate transfection of plasmids containing...Full Text Available
HIV-1 nonsubtype B variants account for the majority of HIV infections worldwide. Drug resistance in individuals who have never undergone antiretroviral therapy can lead to early failure and...Full Text Available
By isomorphous replacement of silicon by phosphorus the authors have synthesized crystalline aluminosilicophosphates with structures of the zeolites type A and faujasite. They determine the adsorption capacity of specimens treated at 575-1275/sup 0/K. They show that the thermal stability and acid resistance of aluminosilicophosphates depend on the quantity of phosphorus in their structure.
Sugarcane rusts, brown (caused by Puccinia melanocephala) and orange (caused by P. kuehnii), are agronomically important diseases in Florida. Cultivar resistance is the best means of managing these diseases. Unfortunately, natural infection of brown rust is not always efficient in determining resist...
A copper-resistant strain (09906) of Pseudomonas fluorescens that was isolated from a citrus grove soil is being investigated as a biological control agent for Phytophthora root rot. Since citrus grove...Full Text Available
The resistance to destruction of spores of Bacillus subtilis var. niger occluded in crystals of calcium carbonate and exposed to ethylene oxide and moist and dry heat...Full Text Available
The pyrethroid knockdown resistance gene (kdr) has become widespread in Anopheles gambiae in West Africa. A trial to test the continuing efficacy of insecticide-treated...Full Text Available
We have evaluated the performance of two rapid, low-cost methods for the detection of ofloxacin (OFX) resistance with 95 Mycobacterium tuberculosis isolates from countries with high...Full Text Available
Resistance (R) protein mediated recognition of pathogen avirulence effectors triggers signaling that induces a very robust form of species-specific immunity in plants. The soybean Rpg1-b protein mediates...Full Text Available
The evolution of drug resistant bacteria is a severe public health problem, both in hospitals and in the community. Currently, some countries aim at concentrating highly specialized services in large...Full Text Available
Link to USGS home page Results of Electrical Resistivity Data Collected near the Town of Guernsey, Platte County, Wyoming By Robert R. McDougal, Jared D. Abraham, and Robert J....
A 42% (70 of 167 isolates) incidence of resistance to 20 micrograms of trimethoprim per ml was found among clinical isolates of coagulase-negative staphylococci from two hospitals. A specific trimethoprim...Full Text Available
Aluminium (Al3+) toxicity is the primary factor limiting crop production on acidic soils worldwide. In addition to an application of lime for soil amelioration, Al3+ resistant plant varieties have been deployed to raise productivity on such hostile soils. This has been possible due to the exploita...
Purpose:Methicillin-resistant Staphylococcus aureus (MRSA) strains are commonly classified as hospital-acquired (HA) or community-acquired (CA). Typical HA-MRSA...Full Text Available
Cross-resistance to cefoxitin (FOX), chloramphenicol (CMP), and quinolones (nalidixic acid [NAL]) related to a putative efflux system overexpression has recently been reported for Klebsiella...Full Text Available
Tetracycline-resistant Lactococcus lactis strains originally isolated from Polish raw milk were analyzed for the ability to transfer their antibiotic resistance genes in vitro, using...Full Text Available
Infection due to multidrug resistance pathogens is difficult to manage due to bacterial virulence factors and because of a relatively limited choice of antimicrobial agents. Thus, it is imperative to...Full Text Available
Although cross-resistance in houseflies to the organophosphates has eliminated numerous potentially useful compounds from field use, the ”subgroup” specificity of this phenomenon has...Full Text Available
Juvenile hormone analog (JHA) insecticides are relatively nontoxic to vertebrates and offer effective control of certain insect pests. Recent reports of resistance in whiteflies and mosquitoes demonstrate...Full Text Available
The development of azole resistance in Candida albicans is most problematic in patients with AIDS who receive long courses of drug for therapy or prevention of oral candidiasis. Recently,...Full Text Available
Insulin resistance in skeletal muscle is a key phenotype associated with type 2 diabetes (T2D) for which the molecular mediators remain unclear. We therefore conducted an expression analysis of human...Full Text Available
The presence of highly heat-resistant spores of Bacillus sporothermodurans in ultrahigh-temperature or sterilized consumer milk has emerged as an important item in the dairy industry....Full Text Available
Extended-spectrum beta-lactamases (ESBL) constitute a key antibiotic-resistance mechanism affecting Gram-negative bacteria, and also an excellent model for studying evolution in real time. A shift in...Full Text Available
In Staphylococcus aureus, a pronounced shift in position of the acriflavin resistance locus was observed when gene order was determined by marker frequency analysis of cells of various ages. In young cells (2-hour culture), acriflavin resistance was mappe...
We compared MRSA Select to mannitol-salt agar with 8 μg/ml cefoxitin for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from 6,199 clinical...Full Text Available
The aim of this study was to evaluate a nitrate reductase assay (NRA) performed on smear-positive sputa for the direct detection of rifampin resistance in Mycobacterium tuberculosis....Full Text Available
Denaturing high-performance liquid chromatography (DHPLC) has been used extensively to detect genetic variation. We used this method to detect and identify Yersinia pestis KIM5 ciprofloxacin-resistant...Full Text Available
Cracking resistance and metal damage are considered in relation to structural state for steam-pipe fittings during use. An approximate scheme is given for estimating the maximum permissible operating time in the plastic state in relation to the depth of an observed crack-type defect.
BackgroundThe emergence of plasmid-mediated carbapenemases, such as NDM-1 in Enterobacteriaceae is a major public health issue. Since they mediate resistance to...Full Text Available
BackgroundOne virulence property of Borrelia burgdorferi is its resistance to innate immunity, in particular to complement-mediated killing. Serum-resistant B....Full Text Available
Objective:To estimate the prevalence of insulin resistant syndrome (IRS) among newly diagnosed patients with type 2 diabetes and to test their validity against two indices...Full Text Available
The emergence of Escherichia coli that produce extended spectrum β-lactamases (ESBLs) and are multidrug resistant (MDR) poses antibiotic management problems....Full Text Available
Arsenic is one of the most important global environmental pollutants. Here we show that the cyanobacterium Synechocystis sp. strain PCC 6803 contains an arsenic and antimony resistance...Full Text Available
BackgroundMany commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives,...Full Text Available
Experimental data are reported on the micro-irregularities of resistivity in longitudinal and transverse specimens of germanium 0.5 to 0.8 mm in thickness and 25 to 40 mm in width. These data are correlated with the conditions of growth of the crystals. (16 refs).
Acquired resistance to the action of insulin to stimulate glucose transport in skeletal muscle is associated with obesity and promotes the development of type 2 diabetes. In skeletal muscle,...Full Text Available
Adipocyte death has been reported in both obese humans and rodents. However, its role in metabolic disorders, including insulin resistance, hepatic steatosis, and inflammation associated with obesity...Full Text Available
Reciprocal mass crosses and back-crosses were performed between two homogeneous strains of the housefly (Musca domestica L.), representing the extremes in susceptibility and resistance...Full Text Available
Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is...Full Text Available
BackgroundInsecticide-based methods represent the most effective means of blocking the transmission of vector borne diseases. However, insecticide resistance poses a serious threat...Full Text Available
A general model for wakefield-generated instabilities in linear accelerators, originally developed for cumulative beam breakup [1], is applied to the resistive wall instability. The general solution for various bunch charge distributions and application to various accelerator configurations are presented.
Laser surface alloying with gaseous nitrogen was utilized to improve the wear resistance of a Ti-6Al-4V alloy. Wear-resistant composite coatings reinforced by hard TiN dendrites were produced 'in-situ' on a substrate of a Ti-6Al-4V alloy. The hardness and wear resistance of the laser alloyed coating under two-body abrasive and block-on-ring full-sliding wear conditions were significantly enhanced. (orig.)
Study results on long-term thermal and corrosion resistance of packs with electro-insulation layer of aluminium nitride are presented. Structural changes of nitride ceramics and contact zones between metal and ceramics are considered. It is shown that multilayer metallo-ceramic packs, manufactured by gas-phase technology have high electro- and thermophysical properties, high thermal and corrosion resistance relative to cesium vapor, vacuum density as well as high thermo-resistance. 8 refs., 4 figs.
The preparation by sputtering of artificial metallic superlattices is described, as are the results of x-ray structural determinations. Tunneling and resistivity measurements on these materials are reported.
E. coli HB101 cells transformed to tetracycline resistance with the plasmids pMB9 or pBR322 display a 10/sup 5/-10/sup 6/-fold lower plating efficiency on agar containing 440 ..mu..M CdCl/sub 2/ than nontransformed cells. When DNA is inserted into the BamH1 site of the plasmid tet gene, or when DNA spanning the BamH1 site is deleted, tetracycline resistance and cadmium hypersensitivity are both lost. In contrast, insertion of DNA into the ampicillin resistance gene does not affect cadmium hypersensitivity.
Milstar picture Milstar is a series of advanced US military communications satellites designed to provide global jam-resistant communications for military users. ...
We show that the eigenvalue equations describing a cylindrical ideal magnetophydrodynamicsw (MHD) plasma interacting with a thin resistive wall can be put into the standard mathematical form: ??? = ??? ?. This is accomplished by using a finite element basis for the plasma, and by adding an extra degree of freedom corresponding to the electrical current in the thin wall. The standard form allows the use of linear eigenvalue solvers, without additional interations, to compute the complete spectrum of plasma modes in the presence of a surrounding restrictive wall at arbitrary separation. We show that our method recovers standard results in the limits of (1) an infinitely resistive wall (no wall), and (2) a zero resistance wall (ideal wall).
The objective of this animation is to develop a QTL mapping population for locating and characterizing the genes responsible for resistance to tan spot disease of wheat.
Resistance of ALLOY 800 as a PWR/SG tubings to IGC/IGSCC and Ni, Co release into high temperature water was evaluated as compared with ALLOYs 600 and 690. The study to improve the resistance to IGSCC and general corrosion was also made. From the results, ALLOY 800 was evaluated to be the most reliable among the high Ni alloys tested. In addition, the alloy would obtain further reliability in IGSCC and general corrosion resistance by the combined addition of Ti and Nb, and the prior oxidation treatments, respectively. (author).
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 ...
DescriptionThis project investigates in silico the interactive consequences of breeding for parasite resistance and nutritional environment on livestock productivity. The thesis of the work is that conflicting evidence regarding the consequences of breeding for parasite resistance arises from the failure to consider the interactions between host genetics and nutritional environment. Starting with a framework that accounts for the consequences of host nutrition on the development of parasitism, we will (1 [continued...
Megasphaera elsdenii is a lactate-fermenting, obligately anaerobic bacterium commonly present in the gastrointestinal tracts of mammals, including humans. Swine M. elsdenii strains were previously shown to have high levels of tetracycline resistance (MIC = 64->256 micro g/ml) and to carry mosaic (re...
Biofilm-specific antibiotic resistance is influenced by multiple factors. We demonstrated that Pseudomonas aeruginosa tssC1, a gene implicated in type VI secretion (T6S), is important for resistance of biofilms to a subset of antibiotics. We showed that tssC1 expression is induced in biofilms and confirmed that tssC1 is required for T6S. PMID:21784934
The pitting corrosion resistance of three different types of stainless steel implanted with silicon is investigated using the potentiokinetic polarization technique. The specimens are tested in 3% NaCl and 0.1 N HCl solutions. Silicon ion implantation inhibits pitting corrosion of the steels in both aqueous media. The corrosion resistance depends on the silicon dose. Post implantation annealing only slightly alters the localized corrosion. (author).
Resistance exercise has been widely reported to have positive rehabilitation effects for patients with neuromuscular and orthopaedic conditions. This paper presents an optimal design of magneto-rheological fluid dampers for variable resistance exercise devices. Adaptive controls for regulating the resistive force or torque of the device as well as the joint motion are presented. The device provides both isometric and isokinetic strength training for various human joints.
A composition of matter to treat particles entrained in flue gas, is described comprising: a caustic liquid used to adjust resistivity of the entrained particles; and inert particulate matter supporting the caustic liquid for inhibiting chemical action of the caustic liquid until used to adjust the resistivity of the entrained particles, the inert particulate matter supporting sufficient caustic liquid to adjust the resistivity of the entrained particles.
The electrical resistivity at low temperatures (T = 10 to 90 K) of the lithium isotopes /sup 6/Li and /sup 7/Li and of an isotopic mixture /sup 7 +6/Li has been studied. The specimens contained a small amount of chemical impurities. An appreciable difference was observed in the temperature dependence of the resistivity produced both by deformation of the phonon spectrum, related to the change in isotopic composition, and by the presence of chemical impurities making the nonequilibrium part of the electron distribution function more isotropic.
A nationwide antimicrobial resistance surveillance has been conducted since 1997 in Korea. In this study, susceptibility test data generated in 2004 by KONSAR group hospitals were analyzed and compared...Full Text Available
The method of the present invention comprises a step of previously coating a positive type resist on the surface of equipment, a step of solidifying the coated positive type resist and a step of bringing the coated equipment to circumstances for use and cleaning the positive type resist. With such procedures, the amount of radioactive materials deposited on the equipment can be reduced, and redeposition of nuclides on the surface to be cleaned can be prevented. (T.M.)
A series of line fault tests have been conducted at completion of Stage I of the Hokkaido-Honshu HVDC Link of Electric Power Development Co., Ltd., prior to its commercial operation, in order to study transient overvoltages and overcurrents and to confirm safety operation of system protecting devices in case of DC transmission line faults. The Hokkaido-Honshu HVDC Link is a metallic return HVDC overhead line and cable transmission system, currently being a monopolar system. For this, measurements were conducted this time on reverse polarity overvoltages occurring on main line cable, return line overvoltages, fault arc dynamic characteristics, and DC bypass current through the AC system. The results obtained were then compared with the analysis results by the HVDC surge similator or digital simulation conducted for system design prior to the field tests. As a result, a close accordance was found between them, in confirmation of the effectiveness ...
The Nuclear Regulatory Commission (NRC) is conducting an enhanced participatory rulemaking to establish radiological criteria for site cleanup and decommissioning of NRC-licensed facilities. Open public meetings were held during 1993 in Chicago, IL, San Francisco, CA, Boston, MA, Dallas, TX, Philadelphia, PA, Atlanta, GA, and Washington, DC. Interested parties were invited to provide input on the rulemaking issues before the NRC staff develops a draft proposed rule. This report summarizes 3,635 comments categorized from transcripts of the seven workshops and 1,677 comments from 100 NRC docketed letters from individuals and organizations. No analysis or response to the comments is included. The comments reflect a broad spectrum of viewpoints on the issues related to radiological criteria for site cleanup and decommissioning. The NRC also held public meetings on the scope of the Generic Environmental Impact Statement (GEIS) during July 1993. The GEIS meetings were ...
Application of electromagnetic forces to materials processing, so-called {open_quotes}electromagnetic processing of materials (EPM){close_quotes} has been recognized as cutting edge technology, especially in the fields of steelmaking and advanced materials processing in Japan. The history of EPM in Japan is mentioned and the background to promote EPM is described. The current status of research and development of EPM is shown briefly introducing several examples. Regarding the application of high-frequency magnetic field, two topics are dealt with. The first is the improvement of the surface quality of cast steel where an alternating magnetic field is imposed on the molten steel from the outside of the mold, and the second is the induction cold crucible where a considerably large amount of molten intermetallic compound is levitated. Examples of the application of DC magnetic field are the control of molten steel flow in a mold and the suppression of the mixing of ...
Inductively coupled plasma etching of InGaP, AlInP and AlGaP in BI{sub 3} or BBr{sub 3} discharges was investigated as a function of source power, dc chuck bias and plasma composition. InGaP etches at the fastest rates ({gt}6000thinsp{Angstrom}thinspmin{sup {minus}1}) in both chemistries, followed by AlGaP. It is found that AlInP provides an excellent etch stop for the other two materials in both mixtures. The InGaP surface morphology improves with increasing BI{sub 3} or BBr{sub 3} content, and with increasing dc chuck bias. The etched features for this material are highly anisotropic. Etch selectivities for InGaP over SiO{sub 2} and SiN{sub x} of {ge}8 are obtained in both plasma chemistries, and there is no etch incubation time with either mixture, indicating that both can scavenge the native oxide on InGaP, AlGaP and AlInP. {copyright} {ital 1998 American Vacuum Society.}
Inductively coupled plasma etching of InGaP, AlInP and AlGaP in BI_3 or BBr_3 discharges was investigated as a function of source power, dc chuck bias and plasma composition. InGaP etches at the fastest rates (>6000 Angstrom min"-"1) in both chemistries, followed by AlGaP. It is found that AlInP provides an excellent etch stop for the other two materials in both mixtures. The InGaP surface morphology improves with increasing BI_3 or BBr_3 content, and with increasing dc chuck bias. The etched features for this material are highly anisotropic. Etch selectivities for InGaP over SiO_2 and SiN_x of #>=#8 are obtained in both plasma chemistries, and there is no etch incubation time with either mixture, indicating that both can scavenge the native oxide on InGaP, AlGaP and AlInP. copyright 1998 American Vacuum Society.
Stearic acid (C{sub 1}8H{sub 36}O{sub 2}) was treated into Ar and Ar-O{sub 2}(10%) pulsed DC discharge created by a cathode-anode confined system. The samples were placed at the floating potential. The results show that the mass variation of the stearic acid samples after Ar-O{sub 2} plasma exposure is more important than the pure Ar plasma treatments. This comportment demonstrate that the oxygen actives species (O and O{sub 2} in all states) strongly enhance the etching process with regards to A{sup *} species, regardless of their concentration. After treatment by Ar and Ar-O{sub 2} plasma, analyses by X-ray diffraction show a significant structural modification of the samples surface, utilizing Ar-O{sub 2} plasma the modification was more pronounced. The chemical composition evolution shows that the acid function is etched preferentially in the beginning of the treatment (about 5 min) and that after 10 min the carbonic chains seems to be functionalized by oxygen. ...
We demonstrate detection of a single core-shell magnetite-silica nanoparticle (outer diameter #approx#120 nm, moment #approx#10"4#mu#_B) using an Nb dc superconducting quantum interference device (SQUID) with the loop size of 350 nm operational at T < 10 K. The system noise was minimized down to 0.2 #mu##PHI#_0 Hz"-"1"/"2 using a cryogenic SQUID series array pre-amplifier. Initial measurements of an individual magnetic nanoparticle were performed and a clear change of the noise spectra of the nano-SQUID was detected at low frequencies in the presence of the nanoparticle. Similar behaviour was confirmed with an FePt nanoparticle with a larger magnetic moment (diameter #approx#150 nm, moment #approx#10"6#mu#_B). Thus, we demonstrate a magnetic sensor based on a dc nano-SQUID and enabling detection of small moments (potentially down to a few electron spins). Such a sensor is of considerable significance for nanomagnetic metrology and quantum ...
In 1976, the US Department of Energy and New York State - ERDA granted a contract for the development of a +-600 kV dc underground transmission cable system looking to inevitable future requirements in the US for economic, high-capacity, long-distance underground transmission linking remote generating stations to metropolitan load centers. This project was comprehensive and dealt with three separate system components, i.e., cable, splice, and terminals. In each instance, for each component, development required an intensive R and D effort, focused on the following categories: insulating materials, model testing, design of full-scale prototype, manufacturer of prototype, and laboratory development testing. Insulating papers and oils were selected, and model studies performed, for both self-contained type and pipe type oil-filled cables. However, only the pipe cable design was finally designated for full-size cable manufacture and EHV laboratory testing. Each of the ...
This is a multi-color 230-page textbook covering analog electronics at the upper-division level. Text material is intended for a full-year sequence at 2-3 credits per term. Topics include: amplifier thermal considerations; class A IC output stage; class B complementary amplifier; class A and Class B single-ended amplifiers; feedback amplifiers; gain margin and phase margin; compensation; oscillators (Wien-bridge, Hartley, Colpitts, Pierce); piezoelectric crystals, single-pole circuits; single-pole pulse response; single-pole rectangular wave response; comparators; Schmitt triggers; 555 timers; multivibrators; RC attenuators; compensated attenuators; principles of dc-dc conversion; capacitor-based converters; buck converter; boost converter; buck-boost converter. The text is in Adobe Acrobat 4.0 format, complete with Acrobat index. Large font size allows the text to be used with overhead transparencies, on screen with an Acrobat Reader, or in print form.
Since 1994-95 the University of Applied Sciences Berne is working on weather-proof electric bicycles. The main drawbacks of bicycles, no weather-protection, little comfort of the saddle, the difficulty of climbing hills, are to be eliminated. The electro-mechanical drive-train of 'Ultraleichtmobil ULM BE 2000', developed in 1995-96, was mechanically complicated. This resulted in reduced energy-efficiency and intense maintenance. Too, the drive-train was expensive in production. A fully electrical human-power transmission seemed to be the solution to the problems mentioned above. It is appealing not only to the user of the vehicle, but also to the producer and to the persons doing the maintenance. Following an internal study showing the technical feasibility of such an electrical transmission, a controllable DC/DC-converter which allows to operate a pedal-driven generator at maximum efficiency has been developed. The electrical transmission is the ...
Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO_2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed ...
In this paper, an improved soft switched two cell interleaved boost AC/DC converter with high power factor is proposed and investigated. A new auxiliary circuit is designed and added to two cell interleaved boost converter to reduce the switching losses. The proposed auxiliary circuit is implemented using only one auxiliary switch and a minimum number of passive components without an important increase in the cost and complexity of the converter. The main advantage of this auxiliary circuit is that it not only provides zero-voltage-transition (ZVT) for the main switches but also provides soft switching for the auxiliary switch and diodes. Though all semiconductor devices operate under soft switching, they do not have any additional voltage and current stresses. The proposed converter operates successfully in soft switching operation mode for a wide range of input voltage level and the load. In addition, it has advantages such as fewer structure complications, lower ...
Various main circuit equipment with large capacity GTO thyristors are outlined for AC and DC electric cars. The configuration of a PWM converter system is presented for the AC main motor drive system of the Shinkansen trains, and its following features are described: the high power factor control capable of keeping a power factor 100% constantly, energy saving by power regenerative braking, the small triple structure with large capacity reverse-conducting GTO thyristors of 4,500V/3,000A, and the reduction of equivalent interfering current and harmonic current by three phase-triple phase difference operation. Furthermore, a control logic equipment with 16 bit MPU and a main transformer are outlined, and the verification test results of the control logic equipment by an analog model simulation and the combinational test results of the commercial equipment are reported. Prototype VVVF inverter system for DC electric cars is also presented. 6 ...
This paper presents a spatial gaming model with price caps for deregulated electricity markets. There has been heated debate on price caps that have been enforced in deregulated electricity markets. Opponents argue that price caps may send wrong economic signals while advocates argue that price caps are good for damping market power. This paper does not intend to take a stand in the argument. Given the fact that price caps are enforced in several deregulated regional electricity markets in the US, a logical step is to reflect this reality in gaining modeling. However, current gaining models have not included any price cap formulation. This paper is the first one to address the issue. DC power flow equations are used for representing the spatial nature of an electrical network. An algorithm is proposed to find a generalized Nash equilibrium under the enforcement of price caps based on the Kuhn-Tucker Vector Optimization Theorem. Case studies show the successful ...
A multicusp magnetic field plasma surface ion source, normally used for H/sup /minus//ion beam formation, has been modified for the generation of high-intensity, pulsed, heavy negative ion beams suitable for a variety of uses. To date, the source has been utilized to produce mA intensity pulsed beams of more than 24 species. A brief description of the source, and basic pulsed-mode operational data, (e.g., intensity versus cesium oven temperature, sputter probe voltage, and discharge pressure), are given. In addition, illustrative examples of intensity versus time and the mass distributions of ion beams extracted from a number of samples along with emittance data, are also presented. Preliminary results obtained during dc operation of the source under low discharge power conditions suggest that sources of this type may also be used to produce high-intensity (mA) dc beams. The results of these investigations are given, as well, and the technical ...
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.
Solution and dilution enthalpies of aqueous solutions of potassium diclofenac salt (K_DC) were measured by an isoperibolic calorimeter at 298.15 and 318.5?K. Heat capacities of the solutions with concentrations 0.002?0.09?mol?kg?1 were obtained at the temperature interval of 288.15?318.15?K using a scanning adiabatic microcalorimeter. The virial coefficients were derived from Pitzer?s model, and the excess thermodynamic functions of both the solvent and the solute of the solution were calculated. The concentration and temperature dependencies of thermodynamic characteristics of the solution were analyzed and discussed.
Recent research work on adjustable speed pumped storage plants conducted in Japan, the USA and Europe suggests that they have many advantages over fixed-speed plants, and can contribute to power system regulation even in pump mode. This paper describes two types of static frequency converter for such pumped storage plants, especially those with greatly fluctuating heads. The design characteristics and operation of the doubly fed induction machine and the synchronous machine with DC link converter are set out and the devices compared. (UK)
The authors report a two-temperature RF bias stress test on nominal 1.2 W 7.5 GHz GaAs/AlGaAs HBT unit cell amplifiers. MTTF`s of 2020 and 1340 hours were obtained at Tj = 218{degrees}C and 245{degrees}C, respectively, under nominal input bias. An activation energy of 0.42 eV is estimated, consistent with published results for similar devices under DC bias stress.
PulsPlasma nitriding is now one of the established nitriding methods. This article describes PulsPlasma nitriding procedures and the boundary conditions necessary. The special features of PulsPlasma technology compared to DC plasma systems are illustrated. In addition, the process benefits of material treatment using a plasma are examined, as is system type. The article concludes with typical applications of PulsPlasma technology for treatment of stainless steel, cold-working steel, hot-working steel and sintered steel. (orig.)
The DC magnetic susceptibility of the REBa_2F_7 compounds was measured by a SQUID magnetometer in the temperature range 5-300 K. Except for Eu, the other compounds show either Curie law or Curie-Weiss law with relatively small values of paramagnetic Curie temperature, #theta#_p, with effective magnetic moments in the range expected of electronic ground state of the trivalent rare earth ion with appropriate J value. The behaviour of Eu is complex. (orig.).
Electrostatic torsional micro-mirrors have wide spread use in different industries for diverse purposes. This paper investigates the development of superharmonics and chaotic responses in electrostatic torsional micro-mirrors near the pull-in condition. Appearance of nonlinear phenomena is investigated in models accounting for and disregarding the coupling of torsional and flexural deflections. Analysis of the system response to step and harmonic excitation reveals the appearance of DC and AC symmetry breaking. Increasing the amplitude of harmonic excitation, the response in the form of distinct superharmonics changes to a broad band response, where there is loss of periodicity and the response becomes chaotic. Accounting for flexural deflections in coupled model reduces the voltage thresh...
Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.
Experimentally it is shown that a movable grounded metallic plate placed inside a multi-dipole magnetic cage can vary the diffused plasma parameters such as density, plasma potential and electron temperature. Plasma is solely produced in the source section of a double plasma device by a dc hot filament discharge and a low-density plasma is produced in the target section by local ionization of neutral gas by the high energetic electrons coming from the source section. A grounded movable stainless steel plate is inserted in the target section of the device. The floating potential of the plate also changes depending on the position of the plate inside the magnetic cage.
Magnetic behavior in three compounds RTa{sub 3}O{sub 9} (R = Nd, Eu and Ho) with defect-perovskite structures has been investigated by DC magnetic susceptibility. The susceptibility of NdTa{sub 3}O{sub 9} shows strong influence of crystal field. For EuTa{sub 3}O{sub 9} a typical Van Vleck paramagnetism has been observed. HoTa{sub 3}O{sub 9} obeys a Curie-Weiss law above 20 K. (orig.) 8 refs.
The Marine Technology Society 1994 conference was held in Washington, D.C., September 7-9, 1994. Titled Challenges and Opportunities in the Marine Environment, the conference offered a wide variety of presentations. State-of-the-art technology, government policies and regulations, and environmental concerns were addressed. Offshore mining, coastal zone management, marine engineering, oceanographic research, educational issues, and global climate change were also well represented in the presentations. The conference proceedings are organized around the daily sessions and roughly 70% of the papers are included.
This paper presents the first results of a study of plasma nitriding in various regions of a d.c. glow discharge, i.e. on the cathode, on the anode, and on a substrate isolated from the cathode and anode (at plasma potential). The results obtained reveal differences in the growth kinetics and surface morphology of the nitriding layers, depending on the region where the nitriding process took place. The aim of this work was to study the role of low temperature plasma in the plasma nitriding process. The processes were carried out in an apparatus for plasma treatment with a hot anode. (orig.)
An accelerator has limited dynamic range: a chain of accelerators is required to reach high energy. A combination of septa and kicker magnets is frequently used to inject and extract beam from each stage. The kicker magnets typically produce rectangular field pulses with fast rise- and/or fall-times, however the field strength is relatively low. To compensate for their relatively low field strength, the kicker magnets are generally combined with electromagnetic septa. The septa provide relatively strong field strength but are either DC or slow pulsed. This paper discusses injection and extraction systems with particular emphasis on the hardware required for the septa.
A synthesis of papers based on the United Nations Environment Programme meeting on the ozone layer, Washington DC, this book contains valuable information on ongoing and planned activities concerned with stratospheric ozone problems, and presents the recommendations for further action resulting from the meeting. Possible changes in the characteristics of the ozone layer are discussed, together with the environmental, ecological, climatic, economic, and health implications of stratospheric ozone depletion. A comprehensive survey of current research in five European countries, the USA, Canada, and Australia is included and the volume is concluded by the UNEP report of the meeting and a world plan of action.
The half-metallic Heusler alloy Ni{sub 2}MnIn is of high interest for use in spin electronics since at the Ni{sub 2}MnIn/InAs interface a spin polarization of 100% is predicted. We prepare high-quality thin films of 20-60nm thickness by co-evaporation and DC magnetron sputtering. Point-contact Andreev reflection spectroscopy yields a spin polarization of up to 54%. By spectral generalized magneto-optical ellipsometry, the dielectric and magneto-optical properties are determined and ferromagnetic behavior below the Curie temperature T{sub C}=318K is proved.
Using ultrapure samples of polyacrylonitrile (PAN) of 485,000 or 150,000 average molecular weight solution cast in dimethylformamide, the dc conductivity (sigma) of pyrolyzed PAN (PANP) films has been studied for pyrolysis temperatures (T/ sub p/) of 280 to 435/sup 0/C. Conductivity measurements made during pyrolysis indicate the onset of a dramatic increase in sigma for T/sub p/ of 390 to 435/sup 0/C. Conductivities as high as 5 (ohm-cm)/sup -1/ have been observed for T/sub p/ < 435/sup 0/C.
Construction of high voltage transmission lines in a difficult hilly terrain within the limited time frame calls for the adoption of modern management tools for controlling the progress. The activity on node network system for such works, in which parallel and overlapping activities are involved is highly useful and is being used in Himachal Pradesh State Electricity Board. This network system has helped the Board to provide an effective and efficient mode of progress reporting at all levels of functioning. A remarkable example is the control of construction of 190 km - 200 kV dc transmission line within four years and six months.
Photocurrent measurements for stainless steel type 304 in the as-received condition after dc and AV (alternating voltage) passivation have confirmed that significant changes of the passive film properties occur due to AV passivation. The photocurrents were the highest for the sample treated by the AV passivation process (AVPP). The bandgap energy increased from about 2.8 to about 3.05 eV for this treatment. Very similar results have been obtained for pure chromium, which suggests that the AVPP produces a thicker passive film with a less defective nature due to a partial dehydration of the chromium oxide phase in the film.
The addition of a thermionic rf gun [1] and a photocathode rf gun will allow the Advanced Photon Source (APS) linear accelerator (linac) [2] [3] to become a free-electron laser (FEL) driver [4]. As the FEL project progresses, the existing high-charge DC thermionic gun will no longer be critical to APS operation and could be used to generate high-energy or low-energy electrons to drive a slow-positron source. We investigated possibilities to create a useful low-energy source that could operate semi-independently and would have a low neutron background.
The HVDC link across the English Channel, which was brought into service in 1986, has several innovative features. Techniques used in its construction together with recent developments have consolidated the viability of HVDC links for a variety of applications. Outlines the main features of the scheme, including the benefits of interconnecting the British and French 400 kV AC power systems; integration of the UK converter system to the 400 kV AC grid; the DC submarine cables; convertor equipment (particularly the UK installation); and future HVDC developments. 6 refs.
Breakdowns occurring in rf accelerating structures will limit the ultimate performance of future linear colliders such as the Compact Linear Collider (CLIC). Because of the similarity of many aspects of dc and rf breakdown, a dc breakdown study is underway at CERN to better understand the vacuum breakdown mechanism in a simple setup. Measurements of the field enhancement factor ? show that the local breakdown field is constant and depends only on the electrode material. With copper electrodes, the local breakdown field is around 10.8GV/m, independent of the gap distance. The ? value characterizes the electrode surface state, and the next macroscopic breakdown field can be well predicted. In breakdown rate experiments, where a constant field is applied to the electrodes, clusters of consecutive breakdowns alternate with quiet periods. The occurrence and lengths of these clusters and quiet periods depend on the evolution of ?. The application of ...
Resistive switching memory is a very promising technology for emerging nonvolatile memory applications. Generally, the switching behavior is triggered by a sweep or pulse voltage. In this paper, a charged capacitor is proposed to be used as the external electrical source to program a resistive switching element. From theoretical analyses based on a set behavior model, the capacitor approach can program the device efficiently. Compared with sweep or pulse mode, capacitor driving method can greatly reduce over-programming after the set event, and thus improve the resistance uniformity. The experimental results performed on Cu/ZrO2:Cu/Pt device support this conclusion quite well. The proposed methodology has great value for achieving a reliable resistive switching, which is important for high...
This paper presents the first report of multiple anthelmintic resistance in the gastrointestinal nematodes of goats and its possible contributory factors in an irrigated area (Pakistan). A total of 18 privately owned Beetal goat flocks were selected in order to determine the anthelmintic resistance against commonly used anthelmintics. Forty to 48 animals from each flock were selected according to their weight and egg count. The three anthelmintics viz., oxfendazole, levamisole and ivermectin, were given to three groups at manufacturer's recommended dose while one group was kept as untreated control. Anthelmintic resistance was determined through faecal egg count reduction and egg hatch tests while assessment of the contributory factors of anthelmintic resistance was measured through the ru...
The present invention concerns a method of evaluating corrosion resistance of a zirconium alloy easily and in a short period of time. An anode polarization curve of the zirconium alloy is measured to obtain an anode polarization curve expressed by logarithm. The curve is converted to a potential-current density curve expressed by absolute values. The peak area in the curve of the converted potential-current density is indicated by numerical values. Further, the corrosion resistance of the zirconium alloy is evaluated based on the peak area converted into the numerical values as a reference. This method is based on the finding that the peak area has a close relation with nodular corrosion resistance, and the corrosion resistance can be judged with respect to a specific zircaloy-2. (T.M.).
This study compares two series of solvents for application in aluminum electrolytic capacitors: ethylene glycol (EG) and water mixtures, and ethylene glycol and 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4) ionic liquid (IL) mixtures. Electrochemical impedance spectroscopy and cyclic voltammetry were carried out with a previously anodized aluminum disk electrode. Comparative measurements of solution resistance, polarization resistance, AC capacitance, and passive current were made. The results show that EG?IL mixtures with low amounts of IL (10% IL?90% EG v/v) have a low solution resistance. Low values of solution resistance, high values of polarization resistance, small passive current, and uniform capacitance of anodized aluminum in EG?IL mixtures are favorable properties of ...
Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30?min IC50 or th...
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.
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).
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.