The UTST (University of Tokyo Spherical Tokamak) device was constructed for the purpose of exploring the formation of ultra-high beta ST (Spherical Tokamak) plasma using the double null plasma merging method. When two plasmas merge together to form a single plasma, magnetic field lines reconnect, and the magnetic field energy is converted to the plasma kinetic energy, increasing the plasma beta. The merging start-up has been demonstrated in the TS-3/4, START and MAST devices using coils inside the vacuum vessel and TS-3 plasma obtained 50% beta. In order to demonstrate the start-up in a more reactor relevant situation, UTST has all poloidal field coils outside the vacuum vessel. The first plasma experiment on the UTST was performed from December, 2007. In the result, the plasma obtained 10 kA by using only outer PF coils and single ST was generated at the lower area (z=-0.3 - -1.0[m]) close to a washergun. This result suggests that another ...
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.
... with dynamic gridding capability to account for material ablation, as well as the addition of energy sources and heat transfer augmentation due to ...
Ultra High Vacuum (UHV) test setup for electron gun testing has been developed. The development of next generation light sources and accelerators require development of klystron as a radio frequency power source, and in turn electron gun. This UHV electron gun test setup can be used to test the electron guns ranging from high average current, quasi-continuous wave to high peak current, single pulse etc. An electron gun has been designed, fabricated, assembled and tested for insulation up to 80 kV under the programme to develop high power klystron for future accelerators. Further testing includes the electron emission parameters characterization of the cathode, as it determines the development of a reliable and efficient electron gun with high electron emission current and high life time as well. This needs a clean ultra ...
The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.
To suit the needs of development for manufacture VLSI, we started to investigate liquid metal ion sources (LMIS) and focused ion beam (FIB) in 1984. Many kinds of emitters viz. neddle type, co-axial type and capillary type of Ga and Au LMIS and three kinds of eutectic alloys LMIS (Au-Si, Au-Si-Be, Pd-Ni-Si-Be-B) have been tested. A program which can calculate focused ion guns has been written. Four kinds of foused ion guns have been operated, a fine beam with diametic 0.1 #mu#m is obtained. Using the FIB a scanning ion microscope has been constructed. Some tests of etching and self-developing of nitrocellulose are described. (author).
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.
shading trellis. This array powers all of the electric appliances, including an oven, cooktop, dishwasher, clothes washer and dryer, home entertainment systems (television and...
Consensus reached in the last few years that fourth generation light source will most likely be a X-ray or a UV coherent source based on single-pass high-gain free electron laser (FEL), such as Self Amplified Spontaneous Emission (SASE), or seeded high-gain harmonic-generation (HGHG) free electron lasers. High-gain (>10"7) required for single-pass FEL puts great constrain on the quality of electron beam, and demands detailed distribution information of electron beam in six-dimension. The typical accelerator system for single-pass FEL consists of a photocathode RF gun injection system, a linac and magnetic bunch compressors, and a long undulator. The major challenges in beam diagnostics for single-pass FEL are to characterize the pico-seconds high-brightness electron beam in six-dimension produced by photocathode RF gun injector, and improve the stability and reliability of the photocathode RF ...
Silicone-rubber washers function as damping and articulating elements in cast-aluminum spacers that separate bundle subconductors in each phase of extra-high-voltage transmission lines. Spacer/dampers are located every 3 ft. along transmission lines on Canada's first operational 500 and 735 kV system.
The high-power model of Disk-and Washer (DAW) cavity for electron acceleration is under fabrication. Basic Dimensions of the cavity were determined from aluminum model measurement and electromagnetic field calculation. We have fabricated model made of OFC (Oxygen Free Copper) five times in total. Some details are optimized and corrected, and then the final brazing are proceeding. These model results and present status are described. (author)
In the framework of the Low Emittance Gun (LEG) project, high gradient acceleration of a low emittance electron beam will be necessary. In order to achieve this acceleration, a -500 kV, 250 ns FWHM, pulse will be applied between two electrodes. Those electrodes should sustain the pulsed field without arcing, must not outgas and must not emit electrons. Ion back bombardment, and dark current will be damaging to the electron source as well as for the low emittance beam. Electrodes of commercially available OFE copper, aluminium, stainless steel (SS), titanium and molybdenum were tested, following different procedures including plasma glow discharge cleaning.
Erosion is the main contributing factor to the decrease in lifetime of gun barrels. The precision, muzzle velocity and fire range deteriorate when the surface inside the gun tube is eroded. This study deals with gun barrel material, what happens in the ba...
A 12-month program was conducted to advance the technology of the Electrical Discharge Machining (EDM) process to be applicable to the stringent requirements of gun barrel boring and rifling. The type of barrels employed in the test were .220 swift gun ba...
The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. Such an FEL requires a high energy, high brightness electron beam to drive the FEL instability to saturation. When fed by an RF-photocathode gun, and modified to include two bunch compressor chicanes, the SLAC linac will provide such a high quality beam at 14 GeV and 1-{micro}m normalized emittance. In this paper, we report on recent linac studies, including beam stability and tolerances, longitudinal and transverse feedback systems, conventional and time-resolved diagnostics, and beam collimation systems. Construction and installation of the injector through first bunch compressor will be completed by December 2006, and electron commissioning is scheduled to begin in January of 2007.
15 to 75% of the gun barrel diameter. Similarly, model masses typically vary from 0.01 to 100 .... taining acceptable levels of gun barrel erosion. The ...
screens of fine wire was placed between the gun barrel and the panel to determine whether the gun performance was repeatable. The transducers were placed ...
Background: The nail gun is a commonly utilized tool in carpentry and construction. When used properly with appropriate safety precautions, it can facilitate production and boost efficiency;...Full Text Available
The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he ...
Turbine Afterword The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he envisioned...
A new polarized electron gun for use on the SLC at SLAC has been built and tested. It is a diode gun with a laser driven GaAs photocathode. It is designed to provide short (2ns) pulses of 10 A at 160 kV at 120 Hz. The design features of the gun and results from a testing program on a new and dedicated beam line are presented. Early results from operation on the SLC will also be shown.
The accuracy of stabilized, turreted gun systems like the 120mm gun on the M1A2 Abrams tank and the 30mm gun on the Apache helicopter are limited by, among other things, structural flexure of the gun barrel and support structure. An advanced actuation system based on piezoelectric translators and an optical fiber strain sensing system are described in conjunction with a rapid prototyping workstation for the design of distributed parameter control systems to actively minimize the effects of vibrations caused by traversing rough terrain or weapon firing.
The magnicon is a highly attractive candidate to be the RF source for a future multi-Tev linear collider. Physical models and computer codes have been developed which can provide start-to-end self-consistent simulations of a magnicon, including precise simulations of the high-convergence electron gun, RF-system, magnetic system, and beam collector. The 3-D beam dynamics simulations include realistic fields, finite beam size and transverse space charge effects. The codes allow one to provide steady-state simulations of the entire tube, so as to evaluate transient process of magnicon excitation, parasitic mode self-excitation, stability analysis, and tolerance analysis. The results of the simulations are found to be in good agreement with magnicon experiments. A brief description of the physical models and simulation codes employed will be given.
Automatic weapons such as machine guns and submachine guns are found in the German-speaking region only in special army and police units and appear accordingly rarely in homicides, suicides and accidents. In the following, the findings in two cases of death with the use of machine and submachine guns are presented. The first case was a fatal accident during shooting on a training area (current machine gun of the German army, calibre 7.62 x 51 mm), the second case was a killing during a physical conflict (submachine gun MP 40 from World War II, calibre 9 x 19 mm). In the case with the machine gun autopsy disclosed typical entry holes corresponding to the calibre, but unusually large exit wounds with tissue bridges in the wound ground, measuring 4 x 2.5 cm in diameter. By contrast, the second case (submachine gun) showed "normal" entry and ...
Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an oxygen rich environment, the combination ...
A device for reducing the muzzle blast and flash from large caliber guns is disclosed. A container having a plurality of internal chambers and baffle plates filled with an aqueous foam is mounted to the muzzle of the gun barrel. The foam and chambers co-o...
Gun barrel vibrations lead to dispersion in the shot patterns. Thus, reducing these vibrations should lead to increased accuracy. Since the muzzle is the anti-node for all vibration modes and its vibrations have the greatest effect on shot dispersion, it ...
... used their Phoenics code to simulate the effect of additives, such as talcum powder which was impregnated in combustible cartridge cases, on the ...
end of the barrel. The petal valve and ring seal are inserted behind it, and the gun barrel assembly and HP section are clamped together with hydraulic collars. ...
sabot: A device fitted around or in back of a projectile in a gun barrel or launching tube to support or protect the projectile or to prevent the escape of ...
A decontamination washer for working dresses using liquid and supercritical carbon dioxide were designed and manufactured. The size of reactor for decontamination and solidification is about 16 liter. The system is a closed one with recycling ability of carbon dioxide. The efficiency of recycling of carbon dioxide and that of separation of solutes in carbon dioxide were checked. They met all the design goals. A remote control system of the carbon dioxide flow was set in a control panel. The manufactured decontamination washer was brought to Wolsung nuclear power plants, and installed to check the efficiency of decontamination and the feasibility of usage in nuclear power plants. The elimination of radioactive oil from the contaminated dresses were very high. However, the decontamination factor was lower than the design goal value. It's due to the low removal rate of radioactive particles attached on the dresses.
The FEL rf system was designed for 3.6-MW rf pulses from two klystrons to drive two linacs and one deflection cavity at 1300 MHz. Two 108.33-MHz subharmonic buncher cavities and one fundamental buncher were also built, each powered by a 5-kW amplifier. A single phase-coherent source drives the various amplifiers as well as the grid of the electron gun, which is pulsed at 21.67 MHz. The initial buncher system did not work as well as expected, and the first linac tank required more rf power than anticipated. The light output was extremely sensitive to amplitude and phase errors. More powerful klystrons were developed and installed, and a method was discovered for operating a single subharmonic buncher and allowing the first linac to complete the bunching process. This paper shows the actual configuration used to operate the laser and discusses future improvements.
The FEL RF system was designed for 3.6-MW RF pulses from two klystrons to drive two linacs and one deflection cavity at 1300 MHz. Two 108.33-MHz subharmonic buncher cavities and one fundamental buncher were also built, each powered by a 5-kW amplifier. A single phase-coherent source drives the various amplifiers as well as the grid of the electron gun, which is pulsed at 21.67 MHz. The initial buncher system did not work as well as expected, and the first linac tank required more RF power than anticipated. The light output was extremely sensitive to amplitude and phase errors. More powerful klystrons were developed and installed, and a method was discovered for operating a single subharmonic buncher and allowing the first linac to complete the bunching process. This paper shows the actual configuration used to operate the laser and discusses future improvements.
Time delay neural networks trained with the backpropagation algorithm are derived for the gun fire control system to correct the miss distance between a target and the projectiles from the gun. Its performance is compared to optimum linear filter based on minimum mean square error [R.E. Kalman, A new approach to linear filtering and prediction problems, J. Basic Eng. 82D (1960) 35-44.]. The structure of the proposed neural controller is described and performance results are shown.
It is shown that a gun similar to that in the SSPX could demonstrate the high fields required for Pulsed Spheromak reactors merely by prolonging the pulse. Important considerations are choosing the voltage to exceed ohmic losses; designing the gun to avoid wasteful short-circuiting of current within the gun; and the injection efficiency factor, f, determined by the ''sag'' in the profile of {lambda} = {mu}{sub o}j/B. Typically f = 0.75 in experiments, giving an overall efficiency > 50 % if short-circuiting is avoided. Theoretical transport models agree qualitatively with the need for a finite gradient in h to pump in helicity by current-driven tearing modes and suggest that pressure-driven resistive modes would not compete with current-driven modes during a buildup to ohmic ignition.
... assets, particularly against ballistic missiles with weapons of mass ... more con- ventional missile and gun weapon systems. ... Similarly, space-based ...
For the expansion to 2.0 MTPY of the CVG Bauxilum alumina plant, the area of clarification and red mud washing was rearranged from four 2-thickener-5-washer trains to two 1-thickener-7-washer trains. As a result of this modification, the specific mud handling capacity of the existing tanks should be increased by almost 3-times. The time allowed for control actions was then significantly reduced, leading to the need of an on-line level detection system, in order to achieve a better and faster control of the operation. With this scope, it was developed and installed a new continuous mud level detector that gives the measurement of both mud and turbid zone levels in the tanks. The development of the new instrument started with an existing instrument for density measurements which was completely re-engineered in order to obtain the maximum readability in the densities founded along the full range of the tank height. Actually 28 tanks are equipped ...
The Advanced Photon Source consists of five accelerators. The injection timing system provides the signals required to cause a bunch emitted from the electron gun to navigate through intermediate accelerators to a specific bucket (1 out of 1296) within the storage ring. Two linacs and a positron accumulator ring operate at 60Hz while a booster synchrotron ramps and injects into the storage ring at 2Hz. The distributed, modular VME/VXI-based injection timing system is controlled by two EPICS-based input/output controllers (IOCs). Over 40 VME/VXI cards have been developed to implement the system. Card types range from 352MHz VXI timing modules to VME-based fiber optic fanouts and logic translators/drivers. All timing is distributed with fiber optics. Timing references are derived directly from machine low-level rf of 9.77MHz and 352MHz. The timing references provide triggers to programmable delay generators. Three grades of timing are provided. ...
An original method is proposed for ensuring time-invariant (stationary) interior ballistic parameters in the postprojectile space of a gun barrel. Stationarity of the parameters is achieved by investing the solid-propellant charge with highly original structures that produce the required pressure condition and linear growth of the projectile velocity. Simple relations are obtained for calculating the principal characteristics.
The work reported in this paper is focused on an effective and efficient solution, namely Smart Isolation Mount for Army Guns (SIMAG), to the weapon stabilization and fire control issues facing US Army guns. SIMAG is composed of the optimum integration of two innovative technologies. Vibration Control by Confinement and smart senor/actuator/active control systems. The combined approach may also be applied to a gun barrel to reduce its undesired vibratory motions excited by external and internal disturbances, such as gun firing action. SIMAG reconfigures the distribution and propagation of excess vibration energy and confines vibrations to certain non-critical regions or modes within a structure. Concentrated passive, active, or smart damping elements or cancellation techniques may be applied to more effectively dissipate or cancel the trapped vibrations and to prevent build up in the assembly. As the ...
Vacuum arc with cathode spots on the cold electrode is widely used as a plasma generator in a such kind of devices like metal ion sources, plasma cathode electron guns, thing films deposition facilities and others. Most vacuum arc devices utilize a high voltage discharge across an insulator surface to provide a trigger plasma which in turn initiates the main arc discharge. Operation of vacuum arc in a repetitively pulsed mode required a stable triggering system for the long time. But with a discharge across the insulators the number of stable pulses is limited by 100,000 or little bit more. The better method for vacuum arc ignition is low pressure discharge. As shown in this paper it is possible to increase the lifetime of the ignition system in 10 times at least, but negative characteristic of this system is a relatively high pressure (about 0.1 mtorr). In some kinds of vacuum arc applications it is impermissible because it leads to the ...
A two module electron beam source operating over a wide range of output parameters has been designed and fabricated to be used in conjunction with a pair of electron beam sustained CO_2 lasers. Each module comprised a grid-controlled thermionic electron beam gun including a compact grid pulser for control of the electron beam, a 250 kV thyratron switched modulator for acceleration of the electron beam, a 1 kHz filament heater and a complex computerized control system. The system was designed to reliably produce 45 #mu#s wide electron pulses of 150-200 keV energy, operate at repetition rates of 1-10 pps and current densities of 5-20 mA/cm"2. Additional parameters are listed. The high voltage cathode assembly employs 132 thoriated tungsten filaments distributed over the area of the 250 cm x 10 cm output window. The cathode assembly including the control grids is supported by two high voltage ceramic bushings in a stainless steel vacuum chamber. ...
A previous study demonstrated the advantages that could be obtained in using loose liner naval gun barrel construction, particularly if the liner is autofrettaged. This report deals with the longitudinal forces required to assemble and disassemble such co...
An investigation was conducted to determine the cause of coating residue found in the test gun chambers during qualification firing of 120-mm combustible cartridge case (CCC) ammunition for the MlAl/A2 main battle tank. The CCC is coated with a clear epox...
This Military Working Dog (MWD) was shot in the chest during combat operations in Iraq. Military Working Dogs are critical to the safety and well- being of deployed troops in combat operations and, as such, they are triaged and treated in our combat hospi...
This study analyzed the atmospheric emissions produced by the live firing of a 155 mm Howitzer gun. The study was conducted during a live firing training exercise at a Canadian Forces Base. Air emissions were sampled continuously for 3 hours. Particles and chemicals were accumulated on sampling media during the firing of 69 rounds. A single round was fired using 4 bags of propellants, and an additional 3 rounds were fired using 5 bags of propellant. Samples included particulate matter; hydrogen cyanide; polycyclic aromatic hydrocarbons (PAHs); dinitrotoluene compounds; benzene; toluene; ethylbenzene; xylene; metals; aldehydes; nitric acid; nitric oxide; nitrogen dioxide; hydrogen sulphide; and sulphur dioxide. Samples were collected at 8 m to the left of the gun as well as at 22 m in front of the gun muzzle in the line of fire. Results of the study showed that 60 per cent of the particles were below 10 {mu}m. Formaldehyde ...
To evaluate the effect of plugging the biopsy tract in rabbit liver and the pathologic changes caused by plugging materials. Thirty-two New Zealand White rabbits were divided into four groups (eight rabbits in each) and compared with one another. They were labeled group A (control), B (gelfoam), C (fibrin sealant) or D (NBCA). the liver was exposed and biopsied with an 18G disposable biopsy gun. The inner Tru-cut needle was withdrawn and plugging was undertaken through the outer cannula of the biopsy gun. Bleeding times of each material were compared. The rabbits were sacrificed and pathologically evaluated for 17 days.
Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2#pi#/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures.
A computer model of an electrothermal accelerator has been developed which applies to the plasma generator as well as the gun barrel, and it for the first time allows study of the interdependent physical processes in both components simultaneously. The code comprises a 2D transient description of the plasma arc, a 2D, two-phase interior ballistics module, and a preprocessor delivering the required plasma physical data. Some results on the flow field, pressure and temperature in a typical accelerator are presented, and probable limitations on the performance of such a system are discussed. The code is to be applied to different concepts of electrothermal chemical guns.
A new process for the removal of tar from biosyngas, OLGA (Oil and Gas Washer), is presented. This gas cleaning technology is based on physical principles and is designed to eliminate tar problems that relate to fouling and er pollution. The applied principles are confirmed by experimental validation. OLGA can be operated without suffering from harmful effects on important gasification characteristics as cold gas efficiency, gasifier simplicity, and feedstock flexibility. Some fundamental considerations in the development of OLGA are discussed. Amongst these is a different approach to the tar problem. This approach does not consider the total tar content as decisive in the evaluation of gas cleaning equipment. Instead, evaluation is focussed on whether tar properties as condensation behaviour and water solubility can still occur. A biosyngas free of tar should therefore be synonymous to a biosyngas that is free of tar related problems.
The performance of different polymers used to flocculate red mud particulate materials in the Bayer process can be evaluated on the basis of their efficiency to achieve adequate settling velocities and turbidity levels. In this study, three commercially available flocculants are evaluated under typical conditions found in the last washer of a Bayer plant. The different shear levels are produced by using a modified Couette flow system. Great differences are noticed in the performance of the polymers when they are compared at different dosages and at different shear rate levels. The data collected also suggests that conventional cylinder settling tests may not be adequate to measure the performance of certain types of polymers. (author)
The performance of different polymers used to flocculate red mud particulate materials in the Bayer process can be evaluated on the basis of their efficiency to achieve adequate settling velocities and turbidity levels. In this study, three commercially available flocculants are evaluated under typical conditions found in the last washer of a Bayer plant. The different shear levels are produced by using a modified Couette flow system. Great differences are noticed in the performance of the polymers when they are compared at different dosages and at different shear rate levels. The data collected also suggests that conventional cylinder settling tests may not be adequate to measure the performance of certain types of polymers. (author)
Inductive electromagnetic launchers, or coilguns, use discrete solenoidal coils to accelerate a coaxial conductive armature. To date, Sandia has been using an internally developed code, SLINGSHOT, as a point-mass lumped circuit element simulation tool for modeling coilgun behavior for design and verification purposes. This code has shortcomings in terms of accurately modeling gun performance under stressful electromagnetic propulsion environments. To correct for these limitations, it was decided to attempt to closely couple two Sandia simulation codes, Xyce and ALEGRA, to develop a more rigorous simulation capability for demanding launch applications. This report summarizes the modifications made to each respective code and the path forward to completing interfacing between them.
The physics and technological issues involved in high gradient particle acceleration at high microwave (RF) frequencies are under study at MIT. The 17 GHz photocathode RF gun has a 1 1/2 cell ({pi} mode) room temperature cooper cavity. High power tests have been conducted at 5-10 MW levels with 100 ns pulses. A maximum surface electric field of 250 MV/m was achieved. This corresponds to an average on-axis gradient of 150 MeV/m. The gradient was also verified by a preliminary electron beam energy measurement. Even high gradients are expected in our next cavity design.
A model is presented which describes the formation of surface damage ``gouging`` on the rails that guide rocket sleds. An unbalanced sled can randomly cause a very shallow-angle, oblique impact between the sled shoe and the rail. This damage phenomenon has also been observed in high-velocity guns where the projectile is analogous to the moving sled shoe and the gun barrel is analogous to the stationary rail. At sufficiently high velocity, the oblique impact will produce a thin hot layer of soft material on the contact surfaces. Under the action of a normal moving load, the soft layer lends itself to an anti-symmetric deformation and the formation of a ``hump`` in front of the moving load. A gouge is formed when this hump is overrun by the sled shoe. The phenomenon is simulated numerically using the CTH strong shock physics code, and the results are in good agreement with experimental observation.
The salient features of the near-infrared free-electron laser (FEL) that is under construction at the new Darmstadt superconducting 130-MeV electron accelerator are discussed. Special attention is given to the layout and the parameters of the accelerator, the layout of the planned FEL experiment, the characteristics of the electron gun, the subharmonic chopper-buncher system, and the hybrid undulator system of the Darmstadt FEL. A comparison of the planned Darmstadt FEL with conventional lasers, with respect to the pulse and wavelength region, is presented. 15 refs.
Carbon fibre composite (CFC) was irradiated by hot plasma streams at plasma gun facility MK-200UG. The CFC targets were tested by plasma loads relevant to Edge Localized Modes (ELM) and mitigated disruptions in ITER. Onset condition of CFC evaporation and properties of evaporated carbon were studied by use of infrared pyrometry and visible spectroscopy.
> Develoopments which have imporved fuel core quality and reduced production costs are described. These developments in the melting and casting of uranium ingots arei modification of the crucible and knockout-slide assembly, substitution of uncoated crucibles for coated crucibles, and substitution of a one-piece gun barrel mold for a vertically split mold. (N.W.R.)
We have used an electric gun to measure the initiation thresholds of more than twenty unusual explosive materials as well as the thresholds of several common explosives for comparison. The purpose of the work was to obtain experimental data for a theoretical study of the effects of various chemical groups on the detonation sensitivity of explosives. 2 refs., 3 figs., 1 tab.
The accelerating flow of a lighter continuous phase through a heavier one is considered. Small nonuniformities grow into large ones due to the Rayleigh-Taylor instability. An experiment exemplifying the large bubble formation due to Rayleigh-Taylor instability was performed and simulated using the PHOENICS 84 computer code. The same numerical procedure was applied to the two-phase flow in a gun barrel. It shows that the acceleration provided by the movement of the projectile can cause initial nonuniformities to grow with time.
Physics information for the D and F piles is presented. Thermal conductivity, reactivity, and irradiation levels are included. Concerning the cooling systems: process water control, pressure drip studies, purging studies, corrosion, and gun barrel clearance of expanded graphite are discussed. (GHH)
Several metallurgical coatings have been developed that provide good tribological performances in high-temperature liquid sodium and that are relatively unaffected by neutron fluences to 6 X 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). The coatings that have consistently provided the best tribological performance have been the nickel aluminide diffusion coatings created by the pack cementation process, chromium carbide or Tribaloy 700 trade mark (a nickel-base hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing materials applied by the electro-spark deposition process. The latter process is a relatively recent development for nuclear applications and is expected to find wide usage. Other coating processes, such as plasma-spray coating, sputtering, and chemical vapor deposition, were candidates for use on various ...
A shock wave appears when the release of accumulated energy is instantaneous. For instance, it accompanies gunpowder explosion, electric discharge, laser beam convergence, collision of high-speed objects, release of high-pressure gas, and supersonic flight. The shock wave research center of Institute of Fluid Science, Tohoku University, is engaged in researches to elucidate the basics of various shock wave phenomena and to apply the fruit to engineering, science, and medicine. In this report, some examples of recent application studies at the center are described, and the trend of shock wave researches in the future is introduced. The ultimate state of the stagnation point of a nozzle flow simulating a reentry into the atmosphere is produced by shock wave compression in a free piston shock tube which is a ground-borne experimental apparatus. Los Alamos National Laboratory, U.S., succeeded in generating metallic hydrogen of a crystalline structure by subjecting liquid hydrogen to shock ...
Production of intense negative ion beams in magnetically insulated diodes was studied in order to develop an understanding of this process by measuring the ion-beam parameters as a function of diode and cathode plasma conditions in different magnetically insulated diodes. A coral diode, a racetrack diode, and an annular diode were used. The UCI APEX pulse line, with a nominal output of 1MV, 140kA, was used under matched conditions with a pulse length of 50 nsec. Negative-ion intensity and divergence were measured with Faraday cups and CR-39 track detectors. Cathode plasma was produced by passive dielectric cathodes and later, by an independent plasma gun. Negative-ion currents had an intensity of a few A/cm{sup 2} with a divergence ranging between a few tenths milliradians for an active TiH{sub 2} plasma gun and 300 milliradians for a passive polyethelene cathode. Negative ions were usually emitted from a few hot spots on the cathode surface. ...
The NRL Long Pulse Induction Linac is being employed in a Free Electron Laser (FEL) experiment. The authors present results of beam transport and focusing experiments as well as measurements of the output radiation generated by various magnetic wigglers. The electron gun of the accelerator presently has a 17-cmdiam. cold cathode which is located in a nearly zero magnetic field (B /SUB z/ less than or equal to 5 G). The gun voltage is flat to within approx. = + or - 5% for 1.5 #mu#sec with this graphite brush cathode. The beam is focused by a series of solenoidal coils as it propagates through the 4-m-long accelerator."2 A solenoidal field which can be varied from 1-10 kG confines the beam in the FEL interaction region. Previous experiments were limited by poor beam transport, focusing, and matching into the relatively large solenoidal field in the FEL region. By smoothing the axial magnetic field profile in the accelerator and making a more ...
Following the Hungerford Massacre the British Government imposed additional strict firearms legislation in 1988 that involved several classes of arms being placed into the prohibited category. By way of compensation a scheme was introduced to allow the unrestricted possession and transfer of the newly prohibited arms, other firearms and "prohibited weapons", if de-activated to a standard acceptable to the Secretary of State. Approved standards for firearm de-activation were drawn up in 1989. The inspection of the de-activated arms was devolved to the two Gun Barrel Proof Houses at London and Birmingham, as otherwise the task of inspecting the thousands of guns involved would have overloaded the firearms section at the Huntingdon Forensic Science Service Laboratory, who were already dealing with criminal firearms cases submitted by 41 of the 43 police forces throughout England and Wales, as well as providing technical assistance to the Home ...
A troubling reality in today's political climate is that many political leaders actually believe that the best way to change schools is through an "end of a gun barrel" approach, rather than by building consensus. In this article, the author examines the reality of high-stakes testing from several perspectives, including the politics of coercion, politics of performance, and the politics of perception. The author discusses that high-stakes testing is a politically charged issue that has had a tremendous impact on the way schools operate; however, teachers must not be afraid to keep their perspective and must encourage a healthy, honest dialogue about the role of testing and engage in political debate.
Electron energy loss (EEL) spectroscopy and high angle annular dark field (HAADF) imaging in aberration-corrected electron microscopes are powerful techniques to determine the chemical composition and structure of materials at atomic resolution. We have implemented Smart Acquisition, a flexible system of scanning transmission electron microsocpy (STEM) beam position control and EELS collection, on two aberration-corrected dedicated cold field emission gun (FEG) STEMs located at SuperSTEM, Daresbury Laboratory. This allows the collection of EEL spectra from spatially defined areas with a much lower electron dose possible than existing techniques such as spectrum imaging.
We have constructed an apparatus to study electron impact ionization of ions which should provide additional insight into the mechanisms involved. Using multiparameter coincidence techniques, we will detect both outgoing electrons from ionization process and will be able to analyze the momenta of both particles simultaneously. Coupled with a high resolution electron gun, this information should have broad application to the difficult problem of three bodies interacting via the long range Coulomb force. If sufficient accuracy can be achieved, information regarding the relative phase of the outgoing electron wavefunctions can be obtained.
The feasibility of a high-energy electron cooling device has been studied through tests on a prototype of the electron device. The apparatus consists of a pulsed ((20-60) keV, 2#mu#s) electron gun, a drift region 1 m long and of a depressed collector for recovering the electron energy. Tests on beam optics and energy recovery have been performed, a high-energy recovery efficiency has been attained. Experimental results are discussed in this paper.
Evaluation of grain boundary composition and structure in superplastically deformed AA5083-based alloys (Al-4.5Mg-1.6Mn-0.2Zr) was carried out in a field-emission gun transmission electron microscope (FEG-TEM). During superplastic deformation at high homologous temperatures materials undergo extensive grain boundary sliding (GBS) which creates a flow of defects in the near-boundary region. Recent literature has shown that the grain-boundary composition in Al-Mg alloys is not necessarily the same as the matrix, and that these differences can have an effect on GBS.
To achieve high efficiency for the conversion of electron kinetic energy in an electron beam to electromagnetic energy in a Free Electron Laser (FEL), it is important to improve the beam quality. And hence, it is necessary to study and minimize the emittance growth of the beam. According to the requirements for the beam quality in an FEL, the author analyzed the emittance growth caused by the jump of the electric field in an accelerator, energy increase, wakefield in a waveguide, space charge effect and distribution of particles in a beam as well as the wakefield in a deflect system etc. The author also estimated the emittance change caused by the variation of the microwave field from the gun to the first accelerator for such case.
During the previous 9 months the major part of the Fusion-FEM has been constructed. The 2 MV Insulated Core Transformer, the electron gun, the accelerator, the focusing lenses and the undulator have been tested on-site. In the present - temporary - set-up, the electron beam line consists of a 12 A, 80 keV thermionic electron gun, a 2 MeV dc accelerator, beam transport optics, the undulator and a collector. The gun is mounted in the high voltage terminal, which is now at -2 MV, and the undulator and mm-wave system am at ground potential outside the SF{sub 6}-filled pressure tank. This so-called inverse set-up allows easy access to the larger part of the beam line, the undulator and the mm-wave system, which is important in the conditioning phase. The decelerator and depressed collector am not yet installed. The design of the electron beam line has been optimised using the GPS particle-tracking code and the TOSCA code. The ...
Natural Resources Canada commissioned an informal survey in which 18 organizations, mainly utilities from across Canada were contacted by letter or fax to gather data regarding unit energy consumption (UEC) of space heating, domestic hot water (DHW) heating and appliances. The data was used in updating and refining the residential energy end-use model used at NRCan. The survey included energy load, UEC, efficiency, and per cent saturation for both space heating and water heating equipment for all fuel types including electric, natural gas, oil, wood and propane used in single detached, single attached, apartment and mobile homes. A list of UEC and per cent saturation for major appliances such as refrigerators, freezers, clothes washers and dryers, cooktop/ovens, central air-conditioners, and lighting is also included in the survey. The collected data was presented separately for each organization. The UEC estimates for appliances range from 6255 to 8744 kWh/year. ...
This report details the data, assumptions and methodology for end-use forecasting of appliance energy use in the US residential sector. Our analysis uses the modeling framework provided by the Appliance Model in the Residential End-Use Energy Planning System (REEPS), which was developed by the Electric Power Research Institute. In this modeling framework, appliances include essentially all residential end-uses other than space conditioning end-uses. We have defined a distinct appliance model for each end-use based on a common modeling framework provided in the REEPS software. This report details our development of the following appliance models: refrigerator, freezer, dryer, water heater, clothes washer, dishwasher, lighting, cooking and miscellaneous. Taken together, appliances account for approximately 70% of electricity consumption and 30% of natural gas consumption in the US residential sector. Appliances are thus important to those residential sector policies ...
Section 127 of the Energy Policy Act requires that the Department of Energy (DOE) prepare a report to Congress on the potential for the development and commercialization of appliances that substantially exceed the present federal or state efficiency standards. Candidate high-efficiency appliances must meet several criteria including: the potential exists for substantial improvement (beyond the minimum established in law) of the appliance`s energy efficiency; electric, water, or gas utilities are prepared to support and promote the commercialization of such appliances; manufacturers are unlikely to undertake development and commercialization of such appliances on their own, or development and production would be substantially accelerated by support to manufacturers. This report describes options to improve the efficiency of residential appliances, including water heaters, clothes washers and dryers, refrigerator/freezers, dishwashers, space heating and cooling ...
Among the investigations conducted on the space shuttle flight STS 3 March 1982 was an experiment in which a 1-keV, 100-mA electron gun was pulsed at 3.25 and 4.87 kHz. The resultant waves were measured with a broadband plasma wave receiver. At the time of flight the experimental setup was unique in that the electron beam was square wave modulated and that the shuttle offered relatively long times for in situ measurements of the ionospheric plasma response to the VLF pulsing sequences. In addition to electromagnetic response at the pulsing frequencies the waves exhibited various spectral harmonics as well as the unexpected occurrence of satellite lines around those harmonics. Both phenomena occurred with a variety of different characteristics for different pulsing sequences.
In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.
A new test methodology is described which allows access to loading rates that lie between split Hopkinson bar and shock-loading techniques. Gas gun experiments combined with velocity interferometry techniques have been used to experimentally determine the intermediate strain-rate loading behavior of Coors AD995 alumina and Cercom silicon-carbide rods. Graded-density materials have been used as impactors; thereby eliminating the tension states generated by the radial stress components during the loading phase. Results of these experiments demonstrate that the time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod. This allows access to intermediate loading rates over 5 x 10{sup 3}/s to a few times 10{sup 4}/s.
Shaped charges were first used more than 30 years ago to perforate casing, cement sheath and reservoir to provide selective communication between the reservoir and well bore. Since then, advances have been made in design of shaped charge sand ancillary equipment. Penetration has increased considerably. Miniaturization of equipment allows passing through relatively small restrictions and effectively communicating with reservoirs. Gun debris has been drastically reduced and in some designs eliminated. Deep reservoirs can be effectively penetrated under down-hole environments exceeding 500 F and 20,000 psi. This work covers the problems encountered and reviews successful devices employing shaped charge and explosive technology.
The nucleation of microdamage under dynamic loading was investigated through planar impact experiments accomplished with a light gas gun. The microscopic observation of recovered and sectioned specimens showed that microcracks were nucleated only by cracking of brittle particles inside material. However, for comparison the in situ static tensile tests on the same material conducted with a scanning electron microscope showed that the microcracks were nucleated by many forms those were fracture of ductile matrix, debonding particles from matrix and cracking of brittle particles. The quantitative metallographic observations of the specimens subjected to impact loading showed that most of the cracked particles were situated on grain boundaries of the aluminum matrix. These facts suggested the concept of critical size and incubation time of submicroscopic cavities in the dynamic case and the mechanism of embryo-damage induced nucleation by fracture of brittle particles ...
Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)
The construction and the development of a UV free electron laser have been started under the cooperation of Nihon U, KEK, PNC, ETL and Tohaku U. The project requires a 100MeV S-band electron linear accelerator to expand the oscillation of FEL using fundamental mode to the UV region. The injection system consists of a thermionic RF-gun with a LaB cathode and an {alpha} magnet for magnetic bunching. We are studying to reduce the back-bombardment electrons to realize the macropulse length of 20{mu}sec. Electron beams, up to the energy of 100MeV, are injected into the optical oscillators. Changing the accelerating energy and/or undulator parameters, this system will cover the range from infrared to ultraviolet for the applications in various fields.
This document presents the findings of an extensive study of the ore mining and dressing industry, for the purpose of developing effluent limitations guidelines for existing point sources and standards for performance new sources, to implement Sections 30...
...2010-10-01 false Ordering from Government supply sources. 51.103 Section 51.103...CONTRACTORS Contractor Use of Government Supply Sources 51.103 Ordering from Government supply sources. (a) Contractors placing...
...false Priorities for use of Government supply sources. 208.002 Section 208...ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES 208.002 Priorities for use of Government supply sources. (a)(1)(v)...
Free-electron laser (FEL) experiments have been conducted with the 38-MeV L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University. It is a 1.3 GHz RF linac with a thermoionic gun, and equipped with two 12th and one 6th sub-harmonic prebunchers for producing the high-intensity single-bunch beam with a charge up to 67 nC/bunch. For oscillation experiments of FEL, the gun is replaced with that with a smaller cathode area in order to reduce the emittance of the beam. The normalized emittance has been measured to be 200 {pi} mm-mrad. The linac is operated in the long-pulse mode and one of the 12th sub-harmonic bunchers and the 6th sub-harmonic buncher are operated, so that the time duration of the macropulse is 4 {mu}s and the spacing between micropulses is 9.2 ns. The length of the micropulse is 30-40 ps and the charge in each micropulse is 2 nC. The electron beam from the linac is transported to a wiggler ...
For obtaining radiation less damagable laser mirrors, a preliminary optimization of film fabrication suitable for the analysis of laser damage mechanism has been done as the first step. Here, the optimization requires not only the stable fabrication process but also the ideal film structure i.e., the amorphous and smooth film structure simultaneously, eliminating latently unwanted secondary effects such as light scattering during laser damage test. For this purpose, we adopted the ion assisted deposition (IAD) method and modified the deposition conditions for titanium and tantalum oxide films, both of which compose typical high index layers, and where SiO_2 layers are also chosen as low index layers because of their amorphous and smooth nature, in alternative multilayer laser mirrors. Surface and cross sectional film structures and film crystallinity are compared and characterized, using a high resolution SEM and a x-ray diffractometer, respectively. The fabrication process and the ...
On the basis of cylindrical roller thrust bearings it was systematically examined to what extent PVD-coatings are able to take over the function of EP/AW-additives. The bearings were tested under heavy-duty conditions in order to distinguish very fast the efficiency of different coating-substrate-systems. Several coatings were tested for their ability to protect an un-coated counterpart. So just the washers of the roller bearings were coated, the rollers stayed un-coated. Four Me-C:H-coatings showed the best performance and fulfilled the required criterion for roller bearings in the boundary friction: low loss of mass and hardly surface deviation. Material carryover from the carbonaceous coating to the 100Cr6 steel surface was developed by the Me-C:H-coatings during the tests. This mechanism was able to protect the un-coated rollers. Closer investigations were done with an ESMA analysis (electron beam micro range analysis) on ZrC{sub g}-coatings. It could be seen, ...
Volatile organic compounds (VOC) are an important group of pollutants with adverse effects on humans and the environment. Primary air pollution abatement measures aim at prevention or reduction of pollutant production in industrial production processes, e.g. by improved processes but also by other methods (closed cycle processes, different process materials, etc.). If these measures have been implemented and emissions are still too high, an off-air purification unit must be installed. Biological purification is the method of choice for low pollutant concentrations. Biological purification processes are based on the activity of microorganisms which are capable of biochemical oxidation of organic and some inorganic gaseous compounds into non-polluting or non-odorous compounds. These processes have the advantage that they work at ambient conditions and therefore remove relatively low pollutant concentrations at low investment and operating cost. Lately, biological filters and ...
The advent, in the near future, of compact X-ray sources like Thomson Back-Scattering (TBS) will allow the clinical application of advanced X-ray imaging techniques, such as phase contrast, with higher sensitivity and lower impact in terms of dose delivery. In this work, we theoretically investigated the possibility of using such sources for phase contrast imaging of micro-calcifications included in a breast tissue. In our study we analyzed the phase and amplitude distribution of the TBS source and we showed that this source can be used for phase contrast imaging since the source coherence at the sample position is sufficiently high for achieving good contrast and micrometer spatial resolution. Indeed the spatial coherence of a TBS source is closer to that of a synchrotron radiation source, and much better than that of a laboratory ...
'Small radioactive source results in big accident' have occurred repeatedly in China and worldwide alike. Radioactive source management is one of the key activities for a nuclear power plant to maintain its good safety record and image to the public. From aspects of establishing the management system, centralized storage, periodic accounting, performing whole process control to the source usage and experience feedback etc., the author reports the practice and experience of radioactive source management in Daya Bay Nuclear Power Plant
A spherical-geometry, self-extraction negative ion source has been designed and fabricated. The source utilizes direct surface ionization to form negative ion beams resulting from interactions between high electron affinity gaseous elemental or molecular materials and a negatively biased, spherical-sector LaB{sub 6} surface ionizer maintained at {similar to}1300 K. The design features of this source and principles upon which the source is based are discussed in this report.
The reference medium for brachytherapy dose measurements is water. Accuracy of dose measurements of brachytherapy sources is critically dependent on precise measurement of the source–detector...Full Text Available
A car-borne NaI(Tl) spectrometric system was used together with a {sup 137}Cs source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road.
A car-borne NaI(Tl) spectrometric system was used together with a "1"3"7Cs source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road.
Two sources of negative ions are described. An rf source produces up to 14 ..mu..A beams of He/sup -/ by charge exchange in Rb vapor. The other Source of Negative Ions by Cesium Sputtering (SNICS) produces a wide variety of negative ion beams in the ..mu..A range. Two important features of SNICS are its simple, compact construction and its very good beam emittance (2 to 4..pi..mm mrad MeV/sup 1/2/). Both sources have lifetimes >200 hours and they are used extensively on the Wisconsin EN tandem.
WR 104 is the prototype for a small but growing group of stars that present the remarkably striking appearance of pinwheels. High resolution images of WR 104 show the (apparently) face-on spiral turning with an 8 month period. The pinwheel is assumed to be composed of dust produced via colliding winds in a low-inclination WR+OB binary. These assumptions have been very successful in modeling the imaging, but remain largely untested by spectroscopy. Strong motivation for further study of this system has emerged. Recent theory suggests that some gamma-ray bursts (GRB's) are core-collapse supernovae viewed nearly pole-on. The WC class Wolf-Rayet star in WR 104 is the type of star thought to be a possible GRB progenitor. If the orbit (and thus stellar rotation axes) are pole-on, the effects on Earth's biosphere could be significant. Confrontation of the face-on colliding-wind binary model with eight years of spectroscopy, offering full phase coverage of WR 104, is presented and many of ...
Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (?1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and the spatial cross correlations of different phenomena. Results of these experiments are in favour of a neutron emission model based on ion beam-plasma interaction with three important features: (1) the plasma target is hot and confined during a few 'inertial confinement times'; (2) the ions of the main part of the beam are magnetized and entrapped around the pinch plasma target for a period longer than the characteristic time of the plasma inductive storage system and (3) ion-ion collisions (both fusion collisions, due to head-on impacts and Coulomb collisions) are responsible for neutron emission. Analysis has shown that one of the ways for ...
The paper presents the investigations of plasma streams generated by pulsed plasma gun 'Prosvet' operated with different gases: krypton (m=84) and helium (m=4). Contour parameters of working gas spectral lines (full intensities and half-widths) are used for determination of spatial distributions of the electron density and temperature. Temporal distributions of the spectral lines intensities (both neutrals and ions of working gas), impurity spectral lines and continuum intensities are analyzed. Plasma stream velocity was estimated by time-of-flight method between two monochromators (MUM) connected with photo-multiplier. longitudinal distributions of the plasma pressure for different time moments and varied distances from the accelerator output have been used for investigation of the plasma stream dynamics and study the plasma compression in the focus region for different operational regimes of plasma accelerator. Experiments show that operation regime of the ...
The relative role of the maternal source and the filial sink in controlling the composition of maize (Zea mays L.) kernels is unclear and may be influenced by the genotype and the N...Full Text Available
Polarized electron sources for high energy accelerators took a significant step forward with the introduction of a new laser-driven photocathode source for the SLC in 1992. With an electron beam polarization of >80% and with {approximately}99% uptime during continuous operation, this source is a key factor in the success of the current SLC high-energy physics program. The SLC source performance is used to illustrate both the capabilities and the limitations of solid-state sources. The beam requirements for future colliders are similar to that of the SLC with the addition in most cases of multiple-bunch operation. A design for the next generation accelerator source that can improve the operational characteristics and at least minimize some of the inherent limitations of present sources is presented. Finally, the possibilities for producing ...
Apr 18, 2008 ... The FSS was produced by point-source filtering the individual detector data ... a 1-sigma noise map; and a coverage map giving the count of ...
Sources of industrial emissions of 1,3-butadiene are discussed both by process (production, consumers) and type (equipment leaks, point sources). Quantification of the emissions are presented, as reported...Full Text Available
The present paper describes the development of a radon standard source for use in establishing the traceability of radon concentration measurements in air. Previously, radon generated by bubbling air through a radium salt solution was widely used for calibration of radon measurement equipment; however, the handling of a solid-phase radon source is easier. In the present study, the radioactivity of radon released in a vapor phase was determined from the difference between the radioactivity of the radium and the residual radon progenies in the source. A germanium detector, calibrated using gamma reference sources, was used for these radioactivity measurements. Under equilibrium conditions the radioactivity of the radon released from the radium source was found to be 988 Bq. The source was sealed in a stainless-steel container having a nominal capacity of 6 l to ...
Jan 25, 2006 ... Source positions are determined using matched-filter and centroiding .... The upper 1-sigma statistical error in the full-band counts. ...
A summary of the topics covered in papers presented at the 1995 Brookhaven joint conference on production, neutralization, and application of negative ion beams is given. The conference topics covered included plasma ion sources, plasma seeding of these sources for increased ion production, beam extraction and transport, computer simulation and design studies, and operation of existing and experimental ion source facilities. Application of the sources to accelerator, tokamak, and thin film deposition are discussed. (AIP) {copyright} {ital 1996 American Institute of Physics.}
The authors report an extension of the source imaging method for analyzing three-dimensional sources from three-dimensional correlations. The technique consists of expanding the correlation data and the underlying source function in spherical harmonics and inverting the resulting system of one-dimensional integral equations. With this strategy, they can image the source function quickly, even with the extremely large data sets common in three-dimensional analyses.
Clear effects of the Act on Power Generation from Renewable Energy Sources (EEWaermeG) on the market cannot be recognized both for the depth geothermal energy and ground source geothermal energy. Due to the concrete design of the law a position that is inferior to others is attained in relation to some other renewable energy sources.
An electron accelerator unit is described for electron beam therapy, comprising: a source of an electron beam; means for finally directing at least a portion of the beam to a therapy site, the directing means being mechanically independent of, and electrically isolated from, the source, and having a target area; and means for aligning the source with the directing means, the aligning means comprising means for projecting at least one beam of light from the source toward the target area.
An electron accelerator unit is described for electron beam therapy, comprising: a source of an electron beam; means for finally directing at least a portion of the beam to a therapy site, the directing means being mechanically independent of, and electrically isolated from, the source, and having a target area; and means for aligning the source with the directing means, the aligning means comprising means for projecting at least one beam of light from the source toward the target area.
This document provides a technical basis for the revision of chemical effluent limitations guidelines for the Steam Electric Power Industry reflecting the Best Available Technology Economically Achievable (BATEA) for existing sources, New Source Performance Standards (NSPS) and Pretreatment Standards. The analysis of pollutants and the technologies applicable to their control has been based on specific waste streams of concern.
Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation on the mechanical properties of these alloys are briefly reviewed, and the very limited information on the effects of cryogenic irradiation are outlined. Generating mechanical property data under cold source operating conditions is a daunting prospect. It is clear that the cold source material will be degraded by neutron irradiation, and so the cold source must be designed as a brittle vessel. The continued effective operation of many different cold ...
An analyser for detecting explosives has at least one neutron source and a plurality of gamma ray detectors. An article to be analysed is moved adjacent the source and detectors and is subjected to neutrons which generate gamma rays from any nitrogen in the article. The gamma rays are detected and analysed to determine the nitrogen concentration within the article. In order to achieve an area of uniform detection there are a plurality of detectors equidistant both from the or each source and from the article to be analysed. In order to avoid a decrease in sensitivity away from the source(s) and detectors there may be a second opposing array of source(s) and detectors on the opposite side of the article. For greatest uniformity of detection, a source in one array opposes a detector in the other array and vice versa. Transmission of radiation from the analyser is ...
To respond to an increase of social problems concerning orphan sources in Japan, a working group was formed in the Japan Health Physics Society. In this working group, we investigated how to prevent acute radiation hazard or social panic regarding orphan sources in scrap metal and detection system for orphan sources brought into scrap yards before recycle. For detection system in a scrap yard we conducted an experiment on detectability of monitoring instrument using a radiation source mixed in scrap metal on a truck. The result showed that it was not easy to detect even a high-level source if it was shielded by scrap metal. We also estimated detection limits for radioactive materials in scrap metal by calculation that was validated with experimental data. We summarized present status about orphan sources in Japan and proposed a categorization of orphan ...
The PAH (polycyclic aromatic hydrocarbons) concentration in coastal zones in the Arctic were studied. Assessment in remote areas is difficult because PAHs contamination from fossil fuel discharges and combustion can be masked by PAHs from natural sources, such as oil seeps, bitumens and forest fires. It is believed that the most important source of anthropogenic PAHs in the Arctic is the long range transport of combustion emissions. A comparison study of PAH distribution between the Beaufort Sea and the Barents Sea led to the interpretation of PAH distributions in terms of potential sources and their geochemistry. PAH concentrations in the Barents Sea sediments were found to be 2 to 20 times lower than in the Beaufort Sea sediments; they are believed to be from anthropogenic sources. In the Beaufort Sea the sediments were found to have been derived from natural sources. 7 refs., 2 ...
The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory have been developing rf-driven ion sources for the last two decades. These sources are being used to generate both positive and negative ion beams. Some of these sources are operating in particle accelerators such as the Spallation Neutron Source (SNS) at Oak Ridge, while others are being employed in various industrial ion beam systems. There are four areas where the rf-driven ion sources are commonly used in industry. (1) In semiconductor manufacturing, rf-driven sources have found important applications in plasma etching, ion beam implantation, and ion beam lithography. (2) In material analysis and surface modification, miniature rf-ion sources can be found in focused ion beam systems. They can provide ion beams of essentially any ...
Analysis of the use of information sources by family physicians is important for both practical and theoretical reasons. First, analysis of the ways in which family physicians handle information may...Full Text Available
Behavioral detection of a low-frequency (40 Hz) vibratory dipole at source distances of 1.5–24 cm was measured by classically conditioned respiratory suppression in goldfish (Carassius...Full Text Available
Cultural monitoring was used to study the incidence and sources of salmonellae in a 4160 bird broiler flock during the growing period, transport and processing in a commercial plant. No salmonellae...Full Text Available
Taking the development of large current, negative ion sources which is in progress aiming at nuclear fusion reactors and the development of high luminance ion sources planned as a part of the Omega Project as the examples, the technology for generating high power ion beams is explained. Both these projects are positioned at the limit of the present technology of high power ion beam application as their targeted beam power reaches several tens MW. Consequently, the requirement for the ion sources is severe, and in particular, the generation of the ion beams having large current density with good convergence is beyond all precedents. The application of high power ion sources has been realized as the neutral beam injectors for large tokamaks. Also the hydrogen negative ion source of large current and the electrostatic acceleration technology for negative ion beams have been developed. ...
A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using ...
The Holifield Radioactive Ion Beam Facility (HRIBF) now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility; the choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. A high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the HRIBF because of its low emittance, relatively high ionization efficiencies and ...
The Holifield Radioactive Ion Beam Facility (HRIBF) now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility; the choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. A high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the HRIBF because of its low emittance, relatively high ionization efficiencies and ...
Convolutive mixtures of signals, which are common in acoustic environments, can be difficult to separate into their component sources. Here we present a uniform probabilistic framework to separate...Full Text Available
An understanding of the mechanism of generation of Lg from underground nuclear explosions is essential for seismic monitoring and source discrimination. Near-source scattering of explosion-generated Rg into S appears to be responsible for the low-frequenc...
The electrode structure of an inverted cesium sputtering negative ion source has been modified to produce a convergent Cs/sup +/ beam. The intensities of negative ion beams produced with this electrode structure are approximately an order of magnitude greater than previously obtained.
Recent organic geochemical studies differ radically in their interpretation of the origin of the Gulf coast oils. However all studies since (and including) Thompson, et al. 1989, emphasize the considerable geographic variation in genetic oil types and are in generalized agreement as to the genetic oil types present and their spatial and stratigraphic relationships. In particular it is accepted that the Gulf rim (both north and south) is encircled by a ring of Mesozoic carbonate-sourced oils and that there is also at least one major deep water trend of carbonate-sourced oils in the northern Gulf. It is also generally agreed that many of the Gulf rim oils are of Oxfordian-Kimmeridgian age, though some, like the Sunniland oils of Florida, are of lower Cretaceous origin. Major disagreement still occurs over the sources of the Louisiana offshore oils and onshore Wilcox reservoired oils. One {open_quotes}school of ...
Using the Sloan Digital Sky Survey (SDSS) and the FIRST (Faint Images of the Radio Sky at Twenty Centimeters) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD-type galaxy at the center of a cluster. We cross-correlated the SDSS with the FIRST catalog and measured the richness of the cluster environments surrounding both bent and straight multi-component sources. This led to the discovery and classification of a large number of galaxy clusters out to a redshift of z ~ 0.5. We divided our sample into smaller subgroups based on their optical and radio properties. We find that FR I radio sources are more likely to be found in galaxy clusters than FR II ...
Cultural monitoring was used to determine the incidence and sources of salmonellae in a 4160-bird broiler flock raised on litter in 32 pens. Twenty-five of the pens remained apparently free of salmonellae...Full Text Available
The author demonstrates through a specific example that it is possible to extract rotational energy from a Kerr source (in principle, of arbitrary size but not turned black) through a reversible process by suitably injecting tachyons. (Auth.).
BackgroundBlood spots collected onto filter paper are an established and convenient source of antibodies for serological diagnosis and epidemiological surveys. Although recommendations...Full Text Available
This section presents background information supporting the development of effluent limitations guidelines and standards for the concentrated aquatic animal production (CAAP) point source category. Section 1.1 presents the legal authority to regulate the ...
The polarization of extracted SATURNE II proton beam as a function of different ion source configurations was studied. Two distinct experiments were necessary for this purpose. In the first one, the left-right instrumental asymmetry of the beam polarimeter was determined using an unpolarized beam. In the second one this correction factor was applied to asymmetries measured with the beam from the polarized ion source in all polarization states. The measurements were carried out at the proton beam kinetic energy 0.80 GeV, where the pp-elastic scattering analyzing power is near its maximum. The results confirmed that the two so-called ``unpolarized states`` of the source were polarized to several percent, whereas the absolute values of the beam polarizations in the so-called ``polarized states`` were equal and opposite. It was observed that the hexapole lens of the ion source produced beam polarization in ...
This table contains point-source catalogs for the ~2 Ms exposure of the Chandra Deep ... Source positions are determined using centroid and matched-filter techniques; .... The 1-sigma upper statistical error (Gehrels 1986, ApJ, 303, ...
We have investigated the usefulness of ribotyping for the differentiation of aeromonads isolated from five patients with gastroenteritis and from the source water, treatment plant, and distribution...Full Text Available
...identity of a confidential source and, in the case of...lawful national security intelligence investigation, confidential...only by the confidential source, (v) Disclose investigative...exercise its authority to open to public observation...requires that the meeting be...
The possibility of providing high accuracy of absorption and albedo methods of radiometric testing due to the use of high-energy radiation component that has passed through a barrier and gone from it in the opposite direction as a reference source, is considered. It is shown that the use of high-energy component of penetrating radiation as a reference source decreases the device response to the main interference in a much larger degree than its response to the change of measured parameter. Experiments are performed using steel pipes and plates. "2"4"1Am, "1"3"7Cs and "6"0Co are used as sources.
... If the terminal classes were to be information sources ... current credibility of inputs by classes of terminals; the most ... the stochastic queue lengths. ...
Subcritical source-driven noise measurements are simultaneous Rossia and randomly pulsed neutron measurements that provide measured quantities that can be related to the subcritical neutron multiplication factor. In fact, subcritical source-driven noise measurements should be performed in lieu of Rossia measurements because of the additional information that is obtained from noise measurements such as the spectral ratio and the coherence functions. The basic understanding of source-driven noise analysis measurements can be developed from a point reactor kinetics model to demonstrate how the measured quantities relate to the subcritical neutron multiplication factor.
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This paper describes the performance of AlGaN/GaN HEMTs with 2.4 #mu#m source-drain spacing. So far these are the smallest source-drain spacing AlGaN/GaN HEMTs which have been implemented with a domestic wafer and domestic process. This paper also compares their performance with that of 4 #mu#m source-drain spacing devices. The former exhibit higher drain current, higher gain, and higher efficiency. It is especially significant that the maximum frequency of oscillation noticeably increased. (semiconductor integrated circuits)
Negative ion based neutral beam injector is one of the most attractive heating system in future fusion reactors. In realizing the system, the crucial device which has to be developed is a high intensity negative ion source. Significant progress has been made on the negative ion source in these years. Among them, a few ampere negative ion beam were produced stably, while the divergence of negative ion beams becomes to be as low as < 10 mrad. We consider these results are demonstrating the potential of the negative ion source for the heating device in future reactors.
Source-term codes to predict the release of radionuclides from nuclear waste packages have been developed and implemented worldwide. A survey and initial comparison of the attributes and capabilities of 13 international source-term codes was recently completed. This preliminary analysis focused on comparison of transport factors/processes and solution methods. This initial comparison is a necessary first step in a properly-conceived, systematic benchmarking of source-term codes. Advantages of such a comparison include assurance of the mathematical correctness of implemented models, comparison and quantification of variances introduced by different types of simplifications, and identification and quantification of the impact of near-field processes.
There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th[sup 80+] and Xe[sup 53+]. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.
There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th{sup 80+} and Xe{sup 53+}. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.
The current status and future plans of the Ok Ridge Spallation Neutron Source (ORSNS) are reviewed. The ORSNS is a new project initiated by the U.S. Department of Energy (DOE) beginning October 1, 1995, to prepare the conceptual for a new spallation neutron source. (author) 2 refs.
Operation at ITER specifications of the Kamaboko III ion source for 1000 second pulses of deuterium negative ion beams is underway on the MANTIS test stand. Efficient production of negative ions at low arc power requires injection of cesium into the source, temperature control of the plasma grid, and a period of conditioning of several days. Two different concepts of temperature regulated plasma grids are currently being tested. (author)
Results are described of the study of the analytical applicability of a highly efficient ion source developed for a mass spectrometer. Its ionizer is in the form of a partially closed cavity with a small aperture for leading out ions, heated to a high temperature. The new ion source increases the sensitivity of the apparatus in operations with transuranium elements by almost two orders of magnitude. It is possible to perform isotopic analyses with a high salt content in the sample, and to study the characteristics of nuclear fuel, even without chemical separation of the sample elements.
This study intends to develop an efficient market design for the German electricity market, with particular regard to renewable energy sources. The German electricity market is disintegrated, i.e. market sectors are not coordinated by a central agency but by their own interactions. The first part of the investigation analyzes the interdependences of market sectors, while the second part will analyze funding instruments for renewable energy sources on this basis. (orig.)
In conveyor type irradiators, the movement of conveyor and the product boxes is not there until the source is fully in the irradiation position. In case the conveyor system fails the source must automatically be returned to its shielded storage vault. The dose received by the product during the movement of the source from or to the shield becomes significant if the total dose to be received by the product is small. A study has been carried out for evaluating the transient dose received by onions in the POTON irradiator. The results of the study are discussed in this paper. (author)
A study was made of the timber products processing point source category, for the purpose of developing information to assist the EPA in establishing effluent limitations guidelines and standards to implement sections 301, 304, 306, and 307 of the Federal Water Pollution Control Act Amendments of 1972. The document is the result of that study.
This document presents the findings of a study of the Ink Manufacturing Industry for the purpose of developing effluent limitations and standards, and pretreatment standards for existing and new sources to implement Sections 301, 304, 306, 307 and 501 of ...
A method of calculating the neutron source strength in irradiated Fast Flux Test Facility (FFTF), fuel has been developed and is presented in this paper. This method has been used to perform calculations in support of the reactivity monitoring of the FFTF reactor by the modified source multiplication method during refueling operations. 31 refs.
A new, magnetically insulated negative ion source has recently been discovered which can produce pulsed negative ion beams (H/sup -/, Li/sup -/, and C/sup -/) with intensities of 100-300 A/cm/sup 2/ at 1-4 MeV. This source may provide the basis for a high energy neutral beam system for heating large tokamaks.
It is clarified that the so-caned 'helicity conservation law' is never the conservation equation of the helicity K itself', but is merely 'the time change rate equation of K', which is passively and resultantly determined by the mutually independent volume and surface integral terms. It is shown that since the total helicity K can never be conserved in the real experimental systems, the conjecture of the total helicity invariance is not physically available to real magnetized plasmas in an exact sense. The well-known relaxation theory by Dr. J. B. Taylor is clarified to be neither the variational principle nor the energy principle, but be merely a mathematical calculation, using the variational calculus in order to find the minimum magnetic energy solution from the set of solutions having the same value of K. With the use of auto-correlations for physical quantities, it is presented that a novel basic formulation of an extended generalized ...
Irradiation-assisted stress corrosion cracking (IASCC) of several types of BWR field components fabricated from solution-annealed austenitic stainless steels (SSs), including a core internal weld, were investigated by means of slow-strain-rate test (SSRT), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and field-emission-gun advanced analytical electron microscopy (FEG-AAEM). Based on the results of the tests and analyses, separate effects of neutron fluence, tensile properties, alloying elements and major impurities identified in the American Society for Testing and Materials (ASTM) specifications, minor impurities, water chemistry, and fabrication-related variables were determined. The results indicate strongly that minor impurities not specified by the ASTM-specifications play important roles, probably through a complex synergism with grain-boundary Cr depletion. These impurities, typically associated with steelmaking and component ...
The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 {micro}m thick) that are wrapped around the sample tray assembly. Soda lime spheres ({approx}49 {micro}m in diameter) have been accelerated with a Light Gas Gun into flight-grade Al foils at 6.35 km s{sup -1} to simulate the capture of cometary debris. The experimental craters have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain residue material. Finally, high-precision ...
Nanosatellite space launches could significantly benefit from an electrically powered launch complex, based on an electromagnetic coil launcher. This paper presents results of studies to estimate the required launcher parameters and some fixed facility issues. This study is based on electromagnetic launch, or electromagnetic gun technology, which is constrained to a coaxial geometry to take advantage of the efficiency of closely-coupled coils. A baseline configuration for analysis considers a payload mass of 10 kg, launch velocity of 6 km/s, a second stage solid booster for orbital insertion, and a payload fraction of about 0.1. The launch facility is envisioned as an inclined track, 1-2 km in length, mounted on a hillside at 25 degrees aimed in the orbital inclination of interest. The launcher energy and power requirements fall in the range of 2000 MJ and 2 MW electric. This energy would be supplied by 400 modules of energy storage and magnetic coils. With a prime ...
These classroom guides, designed to accompany the daily CNN (Cable News Network) Newsroom broadcasts for the month of October 2000, provide program rundowns, suggestions for class activities and discussion, student handouts, and a list of related news terms. Top stories include: Chinese authorities detain Falun Gong protesters on Tiananmen Square and Pope John Paul II angers China by canonizing Chinese martyrs, U.S. presidential candidates prepare for the first presidential debate, U.S. presidential candidates debate education issues, Danville, Kentucky prepares for the first U.S. vice presidential debate, and Yugoslav protesters seize parliament (October 2-6); Yugoslavian president Vojislav Kostunica takes office, recent clashes between Arabs and Israelis concern neighboring Arab states, North Korea observes 55 years of communism with celebrations, Al Gore and George W. Bush meet in the second presidential debate, and Violence in the Mideast and an attack on a U.S. ship in Yemen have ...
In 2002 and again in 2003, an investigative journalist unit at ABC News transported a 6.8 kilogram metallic slug of depleted uranium (DU) via shipping container from Istanbul, Turkey to Brooklyn, NY and from Jakarta, Indonesia to Long Beach, CA. Targeted inspection of these shipping containers by Department of Homeland Security (DHS) personnel, included the use of gamma-ray imaging, portal monitors and hand-held radiation detectors, did not uncover the hidden DU. Monte Carlo analysis of the gamma-ray intensity and spectrum of a DU slug and one consisting of highly-enriched uranium (HEU) showed that DU was a proper surrogate for testing the ability of DHS to detect the illicit transport of HEU. Our analysis using MCNP-5 illustrated the ease of fully shielding an HEU sample to avoid detection. The assembly of an Improvised Nuclear Device (IND) -- a crude atomic bomb -- from sub-critical pieces of HEU metal was then examined via Monte Carlo criticality calculations. Nuclear explosive ...
A family of industrial irradiators is being developed by AECL to cover an electron-beam energy range from 5 to 18 MeV at beam powers between 20 and 250 kW. The IMPELA family of irradiators is designed for push button, reliable operation. The major irradiator components are modular, allowing for later upgrades to meet increased demands in either electron or X-ray mode. Interface between the control system, irradiator availability and dose quality assurance is in conformance with the most demanding specifications. The IMPELA irradiators use a klystron-driven, standing-wave, L-band accelerator structure with direct injection from a rugged, triode electron gun. Direct control of the accelerating field during the beam pulse ensures constant output beam energy, independent of beam power. The first member of the family, the IMPELA 10/50 (10 MeV, 50 kW), is in the final stages of assembly at Chalk River Nuclear Laboratories. The IMPELA 10/50 is constructed around a 3.25 m ...
Abstract The Planck-ATCA Coeval Observations (PACO) project collected data between 4.5 and 40 GHz for 482 sources selected within the Australia Telescope 20 GHz (AT20G) catalogue and observed with the Australia Telescope Compact Array. Observations were done almost simultaneously with the-Planck-satellite, in the period between 2009 July and 2010 August. In this paper, we present and discuss the data for the complete sample of 159 sources with-SAT20G > 200-mJy in the South Ecliptic Pole region. The Planck Early Release Compact Source Catalogue (ERCSC) contains 57 of our sources. A comparison between the PACO catalogue and the ERCSC confirms that the reliability of the latter is better than 95-per cent. The missing ERCSC sources are typically associated with the Large Magellanic Cloud, the ...
We observed at 22 GHz with the VLBI array VERA a sample of 1536 sources with correlated flux densities brighter than 200 mJy at 8 GHz. One half of target sources has been detected. The detection limit was around 200 mJy. We derived the correlated flux densities of 877 detected sources in three ranges of projected baseline lengths. The objective of these observations was to determine the suitability of given sources as phase calibrators for dual-beam and phase-referencing observations at high frequencies. Preliminary results indicate that the number of compact extragalactic sources at 22 GHz brighter than a given correlated flux density level is twice less than at 8 GHz.
The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps.
Despite the widely recognized usefulness of the AAPM TG-43 brachytherapy dose calculation formalism, a straightforward application of this approach to describe the dose distribution about intravascular line sources as proposed by TG-60 may be difficult or even impossible, especially when these line sources emit low-energy photons or beta particles. The causes of these limitations are investigated and illustrated by means of some numerical examples. In order to solve the observed limitations an adapted formalism is proposed, intended specifically for the description of the dose rate distribution about line sources but conceptually similar to the TG-43/TG-60 formalism. Several examples are presented to illustrate the usefulness of the proposed line source dose calculation formalism.
The Alpine Foreland Basin is a minor oil and moderate gas province in central Europe. In the Austrian part of the Alpine Foreland Basin, oil and minor thermal gas are thought to be predominantly sourced from Lower Oligocene horizons (Schoneck and Eggerding formations). The source rocks are immature where the oil fields are located and enter the oil window at ca. 4 km depth beneath the Alpine nappes indicating long-distance lateral migration. Most important reservoirs are Upper Cretaceous and Eocene basal sandstones.Stable carbon isotope and biomarker ratios of oils from different reservoirs indicate compositional trends in W-E direction which reflect differences in source, depositional environment (facies), and maturity of potential source rocks. Thermal maturity parameters from oils of di...
Consider the set of source distributions within a fixed maximum relative entropy with respect to a given nominal distribution. Lossless source coding over this relative entropy ball can be approached in more than one way. A problem previously considered is finding a minimax average length source code. The minimizing players are the codeword lengths --- real numbers for arithmetic codes, integers for prefix codes --- while the maximizing players are the uncertain source distributions. Another traditional minimizing objective is the first one considered here, maximum (average) redundancy. This problem reduces to an extension of an exponential Huffman objective treated in the literature but heretofore without direct practical application. In addition to these, this paper examines the related problem of maximal minimax pointwise redundancy and the problem considered by Gawrychowski and Gagie, which, for a ...
Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials.
The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25 MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility. The choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. Although direct-extraction negative ion sources are clearly desirable, the ion formation efficiencies are often too low for practical consideration; for this situation, positive ion sources, in combination with charge exchange, are the logical choice. The ...
Soon there will be only 14 states in two compacts that are able to dispose of Low Level Waste (LLW): the Northwest and Rocky Mountain compact with disposal options in Richland, Washington, and the Atlantic compact with disposal options in Barnwell, South Carolina. How do states not in one of the two compacts dispose of their LLW? The Off-Site Source Recovery Project can take possession and dispose of some of the unwanted transuranic sources at the Waste Isolation Pilot Plant (WIPP). However, there will be no path forward for states outside of the two compacts for disposal of their non-transuranic LLW. A solution that has been much discussed, debated and researched, but has not been put into wide scale practice, is the borehole disposal concept. It is the author's position that companies that drill and explore for oil have been disposing of sources in borehole-like structures for years. It should be noted that these ...
XMM-Newton EPIC observations reveal the population of X-ray sources of the bright Local Group spiral galaxy M 31, a low-star-formation-rate galaxy like the Milky Way, down to a 0.2-4.5 keV luminosity of 4.4E34 erg/s. With the help of X-ray hardness ratios and optical and radio information different source classes can be distinguished. The survey detected 856 sources in an area of 1.24 square degrees. Sources within M 31 are 44 supernova remnants (SNR) and candidates, 18 super-soft sources (SSS), 16 X-ray binaries (XRBs) and candidates, as well as 37 globular cluster sources (GlC) and candidates, i.e. most likely low mass XRBs within the GlC. 567 hard sources may either be XRBs or Crab-like SNRs in M 31 or background AGN. 22 sources are new SNR candidates in M 31 based on X-ray selection criteria. Time variability ...
The 3-D model program was developed to apply a mise-a-la-masse method to linear current sources with optional shapes. Mise-a-la-masse method is a bipolar mapping survey method using current sources installed in wells, and recently has been widely used for direct exploration of geothermal reservoirs. This method is also used for monitoring underground fluid as electrode arrangement of fluid flow tomography for surveying underground fluid (geothermal fluid, underground water, petroleum). In the geothermal reservoir exploration, the casing pipes of wells are used as linear current sources, and measured data are processed as those based on vertical current source. In the largely inclined well, the inclination of current sources should be considered. The 3-D modeling program was developed by difference calculus using the theoretical potential equation and apparent resistivity based on ...
Electron cyclotron resonance (ECR) ion sources possess several advantages over ion sources conventionally used for injectors of electrostatic accelerators: improved reliability, high efficiency, simplicity, and the capability of generating bright, high-current ion beams. We have adapted a high-current ECR source originally developed as an injector for a CW RFQ proton linac to serve as a source of intense negative-ion beams for the Tandem Accelerator Superconducting Cyclotron (TASCC) facility at Chalk River. The range of ion species of the source has been extended from H{sup 1+} alone up to Bi{sup 1+}, with both gaseous and nonvolatile feeds. Two intense negative-ion beams of He{sup -} and O{sup -} have been generated so far with the source coupled to a standard charge-exchange canal. We foresee no major problems generating a broad range of negative ions with ...
Electron cyclotron resonance (ECR) ion sources possess several advantages over ion sources conventionally used for injectors of electrostatic accelerators: improved reliability, high efficiency, simplicity, and the capability of generating bright, high-current ion beams. We have adapted a high-current ECR source originally developed as an injector for a CW RFQ proton linac to serve as a source of intense negative-ion beams for the Tandem Accelerator Superconducting Cyclotron (TASCC) facility at Chalk River. The range of ion species of the source has been extended from H1+ alone up to Bi1+, with both gaseous and nonvolatile feeds. Two intense negative-ion beams of He- and O- have been generated so far with the source coupled to a standard charge-exchange canal. We foresee no major problems generating a broad range of negative ions with this system. (author)
Because the number of neutrons and gamma rays and the energy spectrum of particles from spontaneous fission are well characterized for {sup 252}Cf, it can be used as a timed source of fission neutrons and gamma rays. The first such usage incorporated a {sup 252}Cf source into gas scintillators. This paper describes a timed source of neutrons and gamma rays made by depositing {sup 252}Cf on one electrode of a parallel plate ionization chamber that can then be used for determining detection-system characteristics. The emission time of neutrons from spontaneous fission has also been determined by recording the emission time of prompt gamma rays from a {sup 252}Cf source (not incorporated into a detector) adjacent to the surface of a solid or liquid scintillator. This well characterized source of neutrons can thus be used as a randomly pulsed source for a variety of ...
The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV ..gamma..-rays produced by neutron-decay protons in the reaction p + p ..-->.. ..pi../sup 0/ ..-->.. 2..gamma.. could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point ...
A statistical method is developed to determine the locations of major pollutant sources affecting a distant downwind receptor, provided that air trajectories can be estimated. Probability density functions are estimated which indicate the overall residence time of air parcels over a given geographic region as they travel toward a receptor and residence time for the case of high pollutant concentrations at the receptor. These functions are used to estimate a conditional probability function which indicates the potential for a source region to contribute to high air pollution concentrations. Finally, a source contribution function is formulated to indicate the relative contribution of different source regions to high concentrations at the receptor. The method is tested using data collected at Grand Canyon National Park in 1980. The dominant pathway for air masses arriving at Grand Canyon during this ...
A versatile, high brightness, volume type, low power RF source, capable of producing positive ion beams with intensities as high as 1 mA from gaseous feed materials and microamperes of negative ion beams has been characterized. The source can also be operated as a plasma sputter negative ion source to generate up to 1 mA of a selected species. The performance of the source in the positive and negative volume modes of operation can be greatly enhanced by addition of a removable, water cooled filament assembly in place of the negative sputter probe. For examine, the material utilization efficiencies of gaseous feed species can be more than doubled, total current intensities increased up to 40%, molecular dissociation fractions increased by 20% and minimum operating pressures reduced by a factor of four when operated in the volume mode. These added electrons also favorably effect, as a consequence of lower ...
The power source facilities of JT-60 consist of poloidal magnetic coil power source, toroidal magnetic coil power source, the power generation facility for heating, operation power distribution facility and secondary cooling facility, and at the time of the experiment operation of JT-60, they supply 1300 MVA of instantaneous maximum power to loads. The component machinery and equipment of the power source facilities are installed in about 20 indoor and outdoor places, and their mounted parts are about 15,000 kinds. About 3,000 kinds of spare parts are preserved in 15 exclusively used stores. The managing system for mounted parts and spare parts of JT-60 power source facilities which possesses the functions of rapidly and efficiently carrying out the storage of large quantity of information, mutual relating and retrieval by making mounted parts and spare parts into a data base and ...
Recent analyses of the anisotropy of cosmic rays at 10{sup 18} eV (the AGASA and SUGAR data) show significant excesses from regions close to the galactic centre and Cygnus. Our aim is to check whether such anisotropies can be caused by single sources of charged particles. We investigate propagation of protons in two models of the galactic regular magnetic field (with the irregular component included) assuming that the particles are injected by a short-lived discrete source lying in the direction of the galactic centre. We show that apart from a prompt image of the source, the regular magnetic field may cause delayed images at quite large angular distances from the actual source direction. The image is strongly dependent on the time elapsed after ejection of particles and it is also very sensitive to their energy. For the most favourable conditions for particle acceleration by a young pulsar, the ...
Monte Carlo calculations using the codes PENELOPE and GEANT4 have been performed to characterize the dosimetric parameters of the new 20 mm long catheter based $^{32}$P beta source manufactured by Guidant Corporation. The dose distribution along the transverse axis and the two dimensional dose rate table have been calculated. Also, the dose rate at the reference point, the radial dose function and the anisotropy function were evaluated according to the adapted TG-60 formalism for cylindrical sources. PENELOPE and GEANT4 codes were first verified against previous results corresponding to the old 27 mm Guidant $^{32}$P beta source. The dose rate at the reference point for the unsheathed 27 mm source in water was calculated to be $0.215 \\pm 0.001$ cGy s$^{-1}$ mCi$^{-1}$, for PENELOPE, and $0.2312 \\pm 0.0008$ cGy s$^{-1}$ mCi$^{-1}$, for GEANT4. For the unsheathed 20 mm source these ...
Volume sources is used for standard sources by radioactive measurement using Ge semiconductor detector of environmental sample, e.g. water, soil and etc. that require large volume. The commercial volume source used in measurement of the water sample is made of agar-agar, and that used in measurement of the soil sample is made of alumina powder. When the plastic receptacles of this two kinds of volume sources were damaged, the leakage contents cause contamination. Moreover, if hermetically sealing performance of volume source made of agar-agar fell, volume decrease due to an evaporation off moisture gives an error to radioactive measurement. Therefore, we developed the two type methods using unsaturated polyester resin, vinilester resin, their hardening agent and acrylicresin. The first type is due to dispersing the hydrochloric acid solution included the radioisotopes uniformly in ...
A multi-stage, multi-disk type seismic source was developed as a downhole seismic source. The seismic source is an improved version of the downhole seismic source of a system in which an elastic wave is generated by a weight accelerated by restitutive force of a spring striking the upper part of a laminated structure consisted of metal disks and elastic bodies installed in water in a well. Enhancing the vibration exciting efficiency requires impedance radiated from the disks to be increased. The multi-disk structure was adopted because of restrictions on the disk area under the limiting condition of being inside the well. Further limitation has still existed, which led to finally structuring the multi-disk type to a multi-stage construction to increase the radiated impedance. In order to increase average velocity on the radiation surface, mass relationship between the hammer and the anvil was sought so ...
We present a development of the use of the AAPM TG-43 dose formalism applied to "1"3"7Cs gynecological implant sources. The geometry factor, radial dose function, and anisotropy function of a "1"3"7Cs source modeled after the Nuclear Associates 67-809 series stainless steel jacketed tube source were derived following the AAPM TG-43 formalism. The dose rate distribution through the center of the source using the AAPM TG-43 dose formalism is calculated and compared with the calculations obtained using the Sievert summation and Monte Carlo simulation. The three methods resulted in an agreement within less than 5%, or an isodose rate line agreement within 2 mm. We demonstrate that the AAPM TG-43 formalism can be applied to "1"3"7Cs linear sources and is capable of serving as a "1"3"7Cs dose calculation algorithm that can be used for treatment planning purpose.
AGILE pointed observations performed from July 9, 2007 to October 30, 2009 are a recent, high quality gamma-ray data archive for monitoring studies of medium to high brightness gamma-ray sources in the 30 MeV -50 GeV energy range. We present a variability study of the 1AGL sources over the complete AGILE pointed Observation Blocks (OBs) dataset. The first AGILE Gamma-Ray Imaging Detector (GRID) catalog (Pittori et al. 2009) included a significance-limited (4 sigma) sample of 47 sources (1AGL), detected with a conservative analysis over a first-year non-uniform sky coverage dataset. In this analysis we used data of an improved full Field of View (FOV) event filter, on a much larger (about 27.5 months) observation dataset, analyzing each OB separatedly. This data processing resulted in an improved source list as compared to the 1AGL one. We present here some results on the variability of some of these ...
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 ...
As there are many efforts devoted in order to manage the cancer, here the researcher handle one of these efforts that play a major part in treating the cancer internationally, it is a brachytherapy system. Brachytherapy was carried out mostly with radium sources, but recently some artificial sources are incorporated in this mode of treatment such as Cs-137, Ir-192, Au-198, P-32, Sr-90 and I-125. The research cover history of brachytherapy and radioactive sources used in, techniques of implementation, radiation protection and methods of brachytherapy dose calculation, as well as brachytherapy in radiation and isotopes centre in Khartoum.
Considering the hardware characteristics of the laser-induced plasma X-ray source and the limitations of the conventional cone-beam reconstruction algorithm, a general cone-beam reconstruction algorithm has been developed at our laboratory, in which the motion locus of the X-ray source is an arbitrary curve corresponding to at least a 2{pi} continuous horizontal angular displacement in the coordinate system of the specimen. The preliminary simulation shows that the general cone-beam reconstruction algorithm consistently results in visually satisfactory images.
Considering the hardware characteristics of the laser-induced plasma X-ray source and the limitations of the conventional cone-beam reconstruction algorithm, a general cone-beam reconstruction algorithm has been developed at our laboratory, in which the motion locus of the X-ray source is an arbitrary curve corresponding to at least a 2{pi} continuous horizontal angular displacement in the coordinate system of the specimen. The preliminary simulation shows that the general cone-beam reconstruction algorithm consistently results in visually satisfactory images.
Ammonia gas (NH{sub 3}) has been used as a nitrogen source for plasma source ion implantation processing of electroplated chromium. No evidence was found of increased hydrogen concentrations in the bulk material, implying that ammonia can be used without risking hydrogen embrittlement. The retained nitrogen dose of 2.1 {times} 10{sup 17} N-at/cm{sup 2} is sufficient to increase the surface hardness of electroplated Cr by 24% and decrease the wear rate by a factor of 4.
Two experiments are currently underway to measure the single-particle weak mixing matrix element for the 1064 KeV transition in "2"0"7Pb. One experiment measures the circular polarization of the 1064 KeV gamma ray emitted from an unpolarized source, while the other experiment measures the forward-backward asymmetry of gamma rays emitted from a polarized source. Analysis of the first set of polarized source data yields an upper limit of 46 eV for the single-particle weak mixing matrix element. copyright 1995 American Institute of Physics.
This paper presents calculations of the {sup 252}Cf-source-driven noise analysis measurements for subcritical highly enriched uranium metal cylinders using the Monte Carlo code MCNP-DSP. This code directly calculates the noise analysis data from the {sup 252}Cf- source-driven noise analysis method for both neutron and gamma ray detectors. Direct calculation of experimental observables by the Monte Carlo method allows for the benchmarking of the calculational model and the cross sections and for determining the bias in the calculation.
Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process.
Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process. 11 refs., 8 figs.
Technical Development Document supporting proposed water discharge regulations for the Coal Mining Industry authorized by the Clean Water Act. Proposed regulations include revised best practicable technology limitations, best available technology limitations and new source performance standards for the Coal Mining Industry. Industry operations include: coal preparation and amillary operations, active mining, F bituminous, anthracite and lignite coal, and the reclamation phase of mining.
... Biogas: The green gas? | EurActiv Biogas has become an attractive alternative source of energy in Europe as the renewable fuel ...Graduate Programme Research Analyst Junior Consultant Training Coordinator Post an EU job Biogas: The green gas? Published: 09 April 2010 |...Updated: 06 July 2010 Biogas has become an attractive alternative source of energy in Europe as the renewable fuel serves several policy priorities, ranging from ... Policy Summary Biogas is a renewable energy source that can be used for heating or electricity production. If compressed, it can ...
The physical foundations are described of radionuclide X-ray fluorescence analysis (RXFA) and the table shows the values of K- and L-absorption thresholds and the K- and L-line energies of elements. The calculation of the intensity of characteristic radiation during RXFA proceeds from relations derived for conventional X-ray fluorescence analysis. The choice of the radionuclide source is ruled by the nature of the analysed substance and the used detection technique. The diagram shows the areas of radionuclide sources and the energy of the fluorescence radiation of elements. The table shows the spectra of radionuclide sources suitable for the purposes of RXFA measured by semiconductor Si(Li) and Ge(Li) detectors. (ES).
Slide 10 Slide 11 23 ground-floor apartments Ancillary Information Gathered Median total PAH [mg/g] Slide 15 What are the principal sources of PAHs to urban lakes?...
Research at the world's accelerator- (storage-ring and linac) based light sources is one of the most dynamic and rapidly growing fields of science. It frequently results in direct benefits to society, thereby demonstrating the value of the research with very concrete examples, but this is not widely understood or appreciated outside of the immediate user community. Our growing group of light source communicators from facilities in Europe, Asia, and the Americas, inspired by the Interactions.org Web site created by high-energy (elementary-particle)physics communicators, concluded that a light source community Web site (lightsources.org) would be the best tool for establishing effective collaboration between the communications offices of the world's light sources and to maximize the impact of our efforts. We envision lightsources.org to serve as a one-stop-shopping site for information ...
BackgroundDuplications of stretches of the genome are an important source of individual genetic variation, but their unrecognized presence in laboratory organisms would be a confounding...Full Text Available
Skip to main content About USAID Locations Our Work Public Affairs Careers Business / Policy USAID: From The American People Policy USAID's 50th Anniversary Policy Home »...
and Vendors on the Web Bartleby.com "Great books online." Electronic Texts & Digital Libraries Links to the full text of books and other texts on the Web. Law and Politics...
from a broad range of sources including industrial and consumer products, food additives and drugs that never made it to the market to evaluate the predictive toxicity...
The growth power-time curves of a strain of petroleum bacteria, B-2, in various kinds of cultures containing different kinds of carbon sources, glucose, n-tetradecane, n-hexadecane and n-octadecane, and different kinds of microemulsions have been determined by using a 2277 Thermal Activity Monitor. The curves showed a single peak for cultures containing a single carbon source, glucose, and two peaks for cultures containing two kinds of carbon sources, glucose and one of the n-alkanes. The first peak indicated that bacteria grew by consuming glucose and the second peak indicated that bacteria grew by consuming n-alkane. The curves were complex when the bacterium grows in a microemulsion culture. According to a kinetic equation of bacterial growth under limited conditions, the rate constants of bacterial growth were obtained. The results showed that the microemulsion culture was more appropriate to bacteria to grow on ...
Mitochondrial superoxide production is an important source of reactive oxygen species in cells, and may cause or contribute to ageing and the diseases of ageing. Seven major sites of superoxide...Full Text Available
Local anesthetics are frequently administered in dentistry and thus can be expected to be a major source of drug-related complications in the dental office. Additionally, the dentist will more often...Full Text Available
BackgroundElementary schools represent both a source of childhood sun exposure and a setting for educational interventions.MethodsSun Protection...Full Text Available
BackgroundWith the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional...Full Text Available
Streptococcus agalactiae continues to be a major cause of subclinical mastitis in dairy cattle and a source of economic loss for the industry. Veterinarians are often asked to provide information on...Full Text Available
In this talk, we summarize recent results obtained from the combined neutrino telescopes IceCube and AMANDA. The combined approach, including data taken from both detectors simultaneously, is compared to other analyses that are using IceCube only data. The main benefit of the combined detector is its improved performance at low energies, meaning energies below 1 TeV (close to the energy threshold of the detector). The discussion is focused on the search for extra-terrestrial neutrinos from candidate sources in our Galaxy. Using appropriate cuts, the sensitivity can be optimized for soft spectra neutrino sources. With the resulting data sample, several studies are performed: an unbinned Galactic Plane Scan and a Cygnus region analysis: the Multi Point Source analysis. The current status of these analyses is presented.
High resolution of NMR spectroscopic data of biosamples are a rich source of information on the metabolic response to physiological variation or pathological events. There are many advantages...Full Text Available
The installation and performance of a water source heat pump in Minnesota are discussed. The operating cost was found to be higher than expected. (MHR)
... stenosis. It looks from the transesophageal and the 3-D echo that most of the problem is really ... posterior leaflet, which you can see on the 3-D echo image is a major source. The anterior ...
This document is a collection of spreadsheets detailing on a county by county basis the agricultural crop, agricultural wastes, municipal wastes, and industrial wastes of Virginia that are potential biomass energy sources.
This document is a collection of spreadsheets detailing in a county by county manner the agricultural crop, agricultural wastes, municipal wastes and industrial wastes in Florida that are potential biomass energy sources.
This document is a collection of spreadsheets detailing on a county by county basis the agricultural crop, agricultural wastes, municipal wastes and industrial wastes of Alabama that are potential biomass energy sources.
... The goal of filtering (the sequential Bayesian ... 5] and the unscented Kalman filter (UKF) [16 ... set of deterministically chosen sample (or sigma) points. ...
BackgroundHealth service databases of administrative type can be a useful tool for the study of progression of a disease, but the data reported in such sources could be affected...Full Text Available
... that range from relatively low frequency strong ground motion modeling [Vidale et al., 1985] to high frequency reverse time migration of seismic ...
Solid-state single-photon sources have many desirable features that make them attractive for applications in quantum information processing. However, the phase coherence of such devices can be severely compromised by coupling to the solid-state environment. Here, we study the effects of realistic dephasing environments on a pair of solid-state single photon sources in the context of quantum interference effects such as the Hong-Ou-Mandel dip. By means of exact solutions for the non-Markovian dynamics of the sources, we show that the resulting loss of visibility depends crucially on the timing of photon detection events. Our results demonstrate that the effective visibility can be improved via temporal post-selection, and also that time-resolved interference can be a useful probe of the interaction between the emitter and its host environment.
light-emitting diode A light-emitting diode, or LED, is a semi-conductor light source that emits visible light or invisible infrared radiation. Semi-conductors ...
A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.
... the open source OpenMap Java toolkit from BBN ... 2001), Handbook of Multisensor Data Fusion ... Oxenham (2002), Sensor Registration Using Airlanes ...
Investigation of the Macrokinetics and Energy of Self-Oscillatory Processes of Gasless Combustion of Solid Fuel Mixtures Proposed for the Design of Short-Term Thermal and Electrical Sources
familiarity fire triangle (i.e., fuel, oxidant, and ignition source) are excluded. It Is obvious that for the baseline safety goal for spacecraft this ...
Little is known about the state of experimentation in the field of medicine during the Medieval Islamic era. With few exceptions, most of the contemporary sources on history of medicine propagate the...Full Text Available
Objective and sourcesWe reviewed the epidemiologic literature for PFOA.Data synthesisPerfluorooctanoic acid (PFOA) does not occur naturally but is...Full Text Available
... Environmental Assessment of Proposed Effluent Limitations Guidelines and Standards for the Meat and Poultry Industry Point Source; EPA-821-B-01-008; US ...
discharges. Proposed Stormwater ELG from Construction Sites - EPA has proposed effluent limitations guidelines (ELGs) and new source performance standards (NSPS) to control...
Proton exchange membrane (PEM) fuel cells are energy sources that have the ... for H2 /02 PEM fuel cells because their catalysts have properties suitable for 0 ...
Monte Carlo calculations using the codes PENELOPE and GEANT4 have been performed to characterize the dosimetric properties of monoenergetic photon point sources in water. The dose rate in water has been calculated for energies of interest in brachytherapy, ranging between 10 keV and 2 MeV. A comparison of the results obtained using the two codes with the available data calculated with other Monte Carlo codes is carried out. A chi2-like statistical test is proposed for these comparisons. PENELOPE and GEANT4 show a reasonable agreement for all energies analyzed and distances to the source larger than 1 cm. Significant differences are found at distances from the source up to 1 cm. A similar situation occurs between PENELOPE and EGS4.
1 Recommendations for correct therapy with digoxin from twenty-five sources are reviewed. 2 Some recommendations may be unsuitable for use with high bioavailability...Full Text Available
A new methane cold neutron source has been tested at the IBR-2 pulsed reactor at the Frank Laboratory of Neutron Physics. In a paper the results of experiments at neutron diffractometers HRFD and DN-2 which are placed at the IBR-2 from the methane moderator side are given. A comparison with the results obtained with the conventional water comb-like moderator is performed. The perspectives of the cold source for various kinds of neutron diffraction experiments, including atomic and magnetic structural analysis and real time experiments are discussed. It is shown, that for a huge number of the experiments which are performing at both HRFD and DN-2 the methane cold neutron source provides the better conditions than water comb-like moderator.
The development of a new configuration of chemical ionization (CI)-based ion source is presented. The ambient air containing the gaseous sample is sniffed into an enclosed ionization chamber which is of sub-ambient pressure, and is subsequently mixed with metastable species in front of the ion inlet of the mass spectrometer. Metastable helium atoms (He*) are used in this study as the primary ionizing agents and are generated from a dielectric barrier discharge (DBD) source. The DBD is powered by an AC high-voltage supply and the configuration of the electrodes is in such a way that the generated plasma is confined within the discharge tube and is not extended into the ionization chamber. The construction of the ion source is simple, and volatile compounds released from the bulky sample can...
Numerous bacteria from a salt-marsh environment are capable of degrading malathion, an organophosphate insecticide, when supplied with additional nutrients as energy and carbon sources. Seven isolates...Full Text Available
A project is underway at Oak Ridge National Laboratory (ORNL) to design, test, and install a cold neutron source facility in the High Flux Isotope Reactor (HFIR). This new cold source employs supercritical hydrogen at cryogenic temperatures both as the medium for neutron moderation and as the working fluid for removal of internally-generated nuclear heating. The competing design goals of minimizing moderator vessel mass and providing adequate structural integrity for the vessel motivated the requirement of detailed multidimensional thermal-hydraulic analyses of the moderator vessel as a critical design subtask. This paper provides a summary review of the HFIR cold source moderator vessel design and a description of the thermal-hydraulic studies that were carried out to support the vessel development.
... increasing its economic results, tapping mew financial sources and augmenting its income, but also a basic task in financial and tax management. ...
Following a brief overview of the terrestrial distribution of boron in rocks, soil, and water, the history of the discovery, early utilization, and geologic origin of borate minerals is summarized....Full Text Available
Fire-driven deforestation is the major source of carbon emissions from Amazonia. Recent expansion of mechanized agriculture in forested regions of Amazonia ...
A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.
... applications related to military and intelligence area ... the technology solved yet, but the open issue still ... fields, columns; ie data source, document type ...
Hydrogen peroxide is a commonly used oxidizing agent with a variety of uses depending on its concentration. Ingestion of hydrogen peroxide is not an uncommon source of poisoning, and results in morbidity...Full Text Available
A collection of cost estimating relationships (CER's) and their proprietary database sources. The cost estimating relationships can be used in the aerospace ...
Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational ...
Maintaining efforts at the end of a very average year in terms of tonnages marketed, maintaining a high degree of vigilance art responsiveness in the face of competition from other energy sources, emphasizing the exemplary safety of industrial plant, and playing an increased role as a source of proposals within the context of dialogue with the authorities in the current environment of stricter regulations. (author)
Diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein (or contre lumière) can be studied most reliably from above...Full Text Available
We review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is described. 25 refs., 1 fig., 3 tabs.
This research validates a novel approach for source tracking based on denaturing gradient gel electrophoresis (DGGE) analysis of DNA extracted from Escherichia coli isolates. Escherichia coli from different animal sources and from river samples upstream from, at, and downstream of a combined sewer overflow were subjected to DGGE to determine sequence variations within the 16S-23S intergenic spacer region (ISR) of the rrnB ribosomal operon. The ISR was analyzed to determine if E. coli isolates from various animal sources could be differentiated from each other. DNA isolated from the E. coli animal sources was PCR amplified to isolate the rrnB operon. To prevent amplification of all 7 E. coli ribosomal operons by PCR amplification using universal primers, sequence-specific primers were utilized for the rrnB operon. Another primer set was then used to prepare samples of the 16S-23S ISR for DGGE. Comparison ...
An irradiation head with sample holders is described and measurement geometry is reported. Measurements were made for optimizing the distance between the source and the sample and for optimizing the sample diameter. The optimal distance between the source and the sample does not depend on the collimator diameter. The sample diameter should not exceed 30 - 35 mm. Sensitivity and detection limits were determined for Zn, Pb and Br and calibration curves were plotted. (M.D.) 6 figs., 2 tabs., 4 refs.
Atmospheric and ionospheric perturbations associated with the acoustic-gravity waves (AGW) with typical frequencies of a few hertz -millihertz are considered. These events may be caused by the influence from space and atmosphere as well as by oscillations of the Earth surface and other near-surface phenomena. The surface sources include long-period oscillations of the Earth's surface, earthquakes, explosions, thermal heating, seisches and tsunami waves. The wavelike phenomena manifest themself as travelling disturbances of air (in the atmosphere) and of electron density (in the ionosphere). Travelling ionospheric disturbances (TIDs) are well detected by radio physical methods. AGW generation by near-surface sources is modeled by the numerical solution of the equation of geophysical fluid dynamics for different sources in two-dimensional non-linear dissipative compressible atmosphere. The numerical calculations are based on ...
We discuss optimal detection of fast radio transients from astrophysical objects while taking into account the effects of propagation through intervening ionized media, including dispersion, scattering and scintillation.Our analysis applies to the giant-pulse phenomenon exhibited by some pulsars, for which we show examples, and to radio pulses from other astrophysical sources, such as prompt radio emission from gamma-ray burst sources and modulated signals from extra-terrestrial civilizations.
A project to demonstrate residential heating and cooling with a well-water source heat pump is documented. The system is schematically illustrated and described, and project experience is discussed. The system is capable of using source water as cool as 40/sup 0/F. Project expenses are accounted for. (LEW)
Brachytherapy consists of sealed radioactive source implantation. The diversity in the nature of radioelements, in their energy and activity requires strict implantation and utilization rules. These rules include radioactive source physical parameters check, after-loading machine and treatment planning system quality assurance and safe and reproducible dosimetric systems. Patient and medical workers information guarantee radioprotection and prevention of accidental exposures. (authors)
This comprehensive guide offers several tried and true steps to help you successfully manage the complex process of developing free software. Topics include project management, developer motivation, technical infrastructure to support collaboration, and project promotion. Producing Open Source Software is ideal for developers starting their own free software projects, or people who simply want to participate in the process.
Daya Bay Nuclear Power Station has made a series of tries and efforts on radiation source control and benefited from them since it was put into commercial operation. Some of them were introduced from experience feedbacks of foreign nuclear power industry and others came from our own good practices
One-velocity angular flux of a neutron field generated by a polarly anisotropic point source in an infinite homogeneous region is calculated in P3 approximation, using the spherical harmonics operator formalism adapted to two-dimensional spherical geometry. The problem is reduced to simple algebraic equations. For weak absorption and linearly anisotropic scattering, the solution is given in closed form. (orig.).
The change of the transport coefficient due to the fusion energy source is studied. The scale invariance property of the reduced set of equations is investigated in the presence of the self-heating term due to the fusion reaction. The pressure gradient as well as the fusion power are the free energy sources that dictate the turbulent transport. It is shown that the burning transport coefficient can have a form with much wider variety, and that the transport property could be different owing to the self-heating by the fusion reactions. (author)
In this report is described the sources to nitrogen emission and how the emission have changed over time. The cost and effect of the proposals given by the Swedish Environmental Protection Agency to cope with the emission of nitrogen to the sea is also treated. A separate chapter describes what we know today about phosphorus and eutrophication Basic document to report SNV--4735. 25 figs, 11 tabs
A brilliant X ray source is proposed for lithography instruments with use of a multi-mirror system. The inverse Compton scattering between the stored electron beam in the storage ring and the stored photon beam in the multi-mirror system, is applied for the X-ray generation. (author)
This research has two main goals; (1) to quantify mechanisms for radon entry into homes of different types and to determine the fraction of indoor radon attributable to each source and (2) to model and calculate the dose (and therefore alpha particle fluence) to cells in the human and animal tracheobronchial tree that is pertinent to induction of bronchogenic carcinoma from inhaled radon daughters.
The proliferation of 'botnets,' phishing schemes, denial-of-service attacks, root kits, and other cyber attack schemes designed to capture a system or network creates a climate of concern for system administrators, especially for those managing accelerator and large experimental-physics facilities, as they are very public targets. This paper will describe the steps being taken at the Advanced Photon Source (APS) to protect the infrastructure of the overall network with emphasis on security for the APS control system.
Hydrology and hydrogeochemical are auxiliary techniques to valid conceptual hydrogeology an recharge models. Stable isotopes from water trace sources and path flow and Tritium indicates age. This paper is about the use of D 18, D2H y 3H to study the aquifer system on Bajo Cauca antioqueno.
High-brightness negative ion beams, especially O{sup -} beams, from a compact gaseous plasma source are studied to evaluate the suitability for high-resolution SIMS. Ion-optical calculations are made using the beam parameters from the new source. Results suggest that sub-100 nm spot with O{sup -} beam current of 10 pA is achievable. Beam focusing, the resulting beam current distributions at the target and the expected instrumental performance are discussed.
Fe, Mn, Ni, V, Ti and Mo were determined in aerosols from manual arc welding. Samples of welding aerosols were trapped on a Synpor 4 filter. The amount of determined elements in aerosols was detected using the method of radionuclide X-ray fluorescence analysis. A /sup 241/Am annular source was used as the source of excitation radiation and radiation was processed using a Si(Li) spectrometer.
Fe, Mn, Ni, V, Ti and Mo were determined in aerosols from manual arc welding. Samples of welding aerosols were trapped on a Synpor 4 filter. The amount of determined elements in aerosols was detected using the method of radionuclide X-ray fluorescence analysis. A "2"4"1Am annular source was used as the source of excitation radiation and radiation was processed using a Si(Li) spectrometer. (E.S.).
Power generated by manufacturers and third-party suppliers in venture capital projects is available to military and other government users at a cost 10 to 20% lower. Tax benefits and other financial incentives keep suppliers' costs low. Users are required to contract for a minimum amount of energy over a 20- to 30-year period. Military use of these energy projects includes sources based on solar energy, cogeneration, geothermal heat, and refuse-derived fuel. (DCK)
Radioactive ion beams (RIBs) of short-lived isotopes of fluorine are in demand for investigating astrophysical phenomena related to the hot CNO cycle and rp processes responsible for stellar nucleosynthesis. Since negative ion beams are required for injection into tandem electrostatic accelerators, such as the 25 MV tandem accelerator used for post acceleration of RIBs for the Holifield Radioactive Ion Beam Facility (HRIBF) research program at the Oak Ridge National Laboratory (ORNL), efficient, direct-formation F{sup -} ion sources are highly desirable for RIB applications involving this type of post-accelerator. We have conceived and evaluated a direct extraction F{sup -} source for potential RIB applications which is predicated on the reverse polarity operation of a positive electron-beam-plasma target/ion source (EBPTIS) while simultaneously feeding fluorine rich compounds and Cs vapor into the ...
This study analyzes the economic impact that could result from the application of effluent standards and limitations issued under Sections 301, 304, 306, 307 of the Clean Water Act to the pulp, paper, and paperboard industry, including builders' paper and roofing felt manufacturing.
Distribution of scattered elements in basic minerals of salt-rocks is studied. It is shown that rubidium and cesium are accumulated mainly in carnallites and are contained in small quantities halites. These elements are accumulated primarily in the carnallite production products, wherein their content in a number of cases exceeds by dozens and hundred times their content in source rocks. It is noted that only carnallites may be considered in the list of actual sources for rubidium and cesium separation
This paper describes the research and development activities in three areas of radiation processing, namely: food irradiation, medical product sterilization and wood plastic combination. Plans and efforts exerted to acquire a larger gamma source to augment our present 5,000 curie source are discussed. Cost estimates for a radiation facility are presented on the basis of the market potential of food irradiation and medical product sterilization. Existing local industries that can benefit from the adaptation of irradiation technology in their processing requirements are described.
Brachytherapy is used for treating certain types of cancer by inserting radioactive sources into tumours. CDTN/CNEN is developing brachytherapy seeds to be used mainly in prostate cancer treatment. Dose calculations play a very significant role in the characterization of the developed seeds. The current state-of-the-art of computation dosimetry relies on Monte Carlo methods using, for instance, MCNP codes. However, deterministic calculations have some advantages, as, for example, short computer time to find solutions. This paper presents a software developed to calculate doses in a two-dimensional space surrounding the seed, using a deterministic algorithm. The analysed seeds consist of capsules similar to IMC6711 (OncoSeed), that are commercially available. The exposure rates and absorbed doses are computed using the Sievert integral and the Meisberger third order polynomial, respectively. The software also allows the isodose visualization at the surface plan. The ...
A large IMF- and event characterizing multidetector system (CHICSI) is under development for storage ring experiments. In ''test'' experiments with telescopes of CHICSI type the IMF production has been measured for "1"4N induced reactions at 14A and 32A MeV. Detailed information about the emission sources, particularly from the IMF yield in reactions with isotope separated targets and from isobaric yield ratios in the sub-Coulomb region is discussed. (orig.).
The electron beam ion source (EBIS) at Texas A and M University was constructed and is currently undergoing tests on the injection and transmission of the electron beam through the solenoid. Results of computer simulation of the electron beam are presented, as well as measurements of electron beam profiles using a pinhole beam analyzer.
The inevitability of sustainable economic development and its linkage to a gradual shift to renewable energy sources, especially solar energy, was discussed. Means to measure sustainability of technology were described, and policy instruments (essentially research, development and demonstration, and punitive taxes on conventional energy carriers) to accelerate the shift to renewable energy sources were outlined.
The apex dimensions and length are calculated as a function of current for the ion-emitting jet in liquid-metal ion sources (LMIS). The results agree well with observations. Since the final expressions are analytical, they give more insight into the fundamental mechanisms involved than do numerical calculations. Some implications of the model are discussed concerning focused ion beam (FIB) systems employing LMIS. (author).
Clastic sediments of Albian age provide hydrocarbon source rocks, reservoirs and seals. Major reservoirs occur in sandstones to the north, and have a limited reservoir potential in offshore Qatar. Distal shales are a major seal in offshore Qatar, the United Arab Emirates and Oman. Local source-rock potential exists in the northern part of the Arabian Gulf and in the extreme SE of Saudi Arabia (in the Rub Al Khali Basin). (author)
The work reported in this paper addresses the problem of structure-borne sound transmission between vibrating sources and ribbed-plate receiver structures. Vibrating sources, such as pumps, motors, fans, etc., transmit vibro-acoustic power, causing noise complaints by occupants in cars, trains, aircraft, buildings and/or material fatigue and damage. The transmission process is complicated in that sources transmit power through several contacts and by up to six components of excitation at each contact. The structure-borne sound power is a function of source activity, source mobility and receiver mobility, and all three quantities must be known to some degree. For non-homogeneous receiver structures, such as thin-plate cavity constructions or lightweight framed constructions, the sheathing plates are typically fastened to the framing members using bolts, screws or spot-welded joints. ...
Full text: Recent geoarchaeological research in the Erzurum district, north-eastern Anatolia, has revealed an abundance of obsidian at numerous neolithic and Bronze Age sites. Geochemical characterisation using neutron activation analysis indicates that the obsidian was obtained from several sources that are chemically distinct from the major sources already known from Central Anatolia an the Lake Van area. Multiple sources are represented in the samples collected from at least two of the sites, namely the sites of Sos and Pulur. The primary source of some of the obsidian utilised at the site of Sos has been located in the volcanic sequence outcropping tot he north-west of Pasinler. Field survey however has shown that the alluvial deposits along the main rivers and some of their tributaries were the main sources of the obsidian utilised at the sites near Erzurum. Trade or exchange ...
In the High Flux Reactor (HFR) at Grenoble a new horizontally arranged cold neutron source will be installed that uses liquid deuterium (D_2) as the moderator for cold neutrons. This cold source should provide a high neutron flux, it should be simple in design, and be characterized by high reliability and by safe operation. A high neutron flux calls for installation of the cold source near the HFR core and good moderation requires a D_2 volume of #DELTA#5 litres. Hence, the moderator, contained in a horizontally arranged cylindrical cell of 21 cm diameter and 20 cm length, is installed at the end nearest to the core of a horizontal beam tube of roughly 4.5 m length with an inner diameter of only 23 cm (Fig. 1). The HFR will be equipped with a second cold neutron source. The installation in the existing horizontal beam tube together with the amount of heat released determined the problems to be solved: ...
A thermoluminescence (TL) sheet and its spatial readout system for in vivo measurement of spatial dose distribution around sources has been newly developed for intracavitary high dose-rate radiation therapy. The TL sheet (40 cm x 50 cm x 200 {mu}m), which is composed of teflon mixed with BaSO{sub 4} (Eu doped) powder, has a linear response with a very wide dynamic range from at least 0.002 cGy to 5000 cGy for {sup 60}Co sources. Phantom test of the TL sheet readout system demonstrated that absorbed dose with TL sheet and that with ionization chamber as standard dosimeter agreed well. For clinical application, TL sheet was attached on an applicator of intracavitary radiation therapy for rectal cancer. After irradiation with high dose-rate {sup 60}Co sources, the in vivo dose distribution on the surface of the rectum was determined. The TL sheet was suggested to provide a convenient means of measuring the dose distribution ...
The detection efficiency of gamma scanning system in irradiated materials examination facility has been measured. Gamma-ray sources used in this experiment are Cs-Co standard sources a PWR spent fuel rod in which {sup 134}Cs and {sup 154}Eu peaks are clearly identified in the energy region of 500 to 1,600 keV. The distance between source and detector is about 1.6 m. A slit type collimator with 3 mm-width window and 30 mm-thick lead block are installed between source and detector. The detector is a HPGe detector. This equipment is mainly used in gamma scanning of irradiated nuclear fuel. The measured detection efficiency seems to be 1.89 x 10{sup -6} % for 1 MeV gamma-ray. With these results the activities of unknown sources could be measured. This results are expected to be used in the measurement of the absolute distribution of gamma emitting nuclides in nuclear fuel.
A brief description of a method for producing relatively intense molecular negative ion beams for the difficult Group IIA elements is given which offers considerable improvement in terms of source operation and beam intensity stability over other methods conventionally utilized. It is particularly suited for use in cesium plasma sources such as the Aarhus geometry and axial geometry versions of the source. The method utilizes H/sub 2/ source feed gas for the production of a hydrogen-rich plasma discharge which sputters a negatively biased probe made of elemental or copper alloy material. Negative ion beams of MgH/sub 3//sup -/>=12 ..mu.. A have been realized during routine operation of the 25 MV tandem accelerator. Negative ion beam intensity data, typical source operational parameters, and examples of mass spectra associated with their production are given. Interesting ...
This research focuses on the development and application of high order statistical analyses applied to measurements performed with subcritical fissile systems driven by an introduced neutron source. The signatures presented are derived from counting statistics of the introduced source and radiation detectors that observe the response of the fissile system. It is demonstrated that successively higher order counting statistics possess progressively higher sensitivity to reactivity. Consequently, these signatures are more sensitive to changes in the composition, fissile mass, and configuration of the fissile assembly. Furthermore, it is shown that these techniques are capable of distinguishing the response of the fissile system to the introduced source from its response to any internal or inherent sources. This ability combined with the enhanced sensitivity of higher order signatures indicates that these ...
The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general ...
An International Workshop on Metrology for X-ray and Neutron Optics has been held March 16-17, 2000, at the Advanced Photon Source, Argonne National Laboratory, near Chicago, Illinois (USA). The workshop gathered engineers and scientists from both the U.S. and around the world to evaluate metrology instrumentation and methods used to characterize surface figure and finish for long grazing incidence optics used in beamlines at synchrotrons radiation sources. This two-day workshop was motivated by the rapid evolution in the performance of x-ray and neutron sources along with requirements in optics figure and finish. More specifically, the performance of future light sources, such as free-electron laser (FEL)-based x-ray sources, is being pushed to new limits in term of both brilliance and coherence. As a consequence, tolerances on surface figure and finish of the next generation of ...
Ground-source heat pump systems (GSHPSs), also referred to as geothermal heat pump systems (GHPSs), have been widely used in residential and commercial buildings for years due to their outstanding energy utilization efficiencies. In this study, an energy and exergy modeling of solar assisted ground-source heat pump systems for residential applications is presented for system analysis and performance evaluation. In this regard, the performance of a solar assisted ground-source heat pump heating system, installed in Solar Energy Institute of Ege University, Izmir, Turkey, is evaluated based on the actual operational data to show how energy and exergy efficiencies values change with the system. The average heating coefficient of performances (as energy efficiencies) of the solar assisted ground-source heat pump (GSHP) unit and the overall system are obtained to be 2.64 and 2.38, respectively. The average ...
The consequences of converting a facility from brown coal fuel to gas fuel were analyzed by model simulation. Treated were a district heating plant with an output of 700 TJ/yr and minor local heating sources (stoves) at a density of 1 family house per 100 m"2. Emissions of particulate matter, sulfur dioxide, nitrogen oxides, carbon monoxide, and hydrocarbons before and after the conversion are given for the two types of source. Conversion of a major air pollution source to gas fuel would result in a reduction of the contribution of sulfur dioxide emissions of the order of 10"-"4, of particulate matter and carbon monoxide of the order of 10"-"3, and of hydrocarbons of the order of 10"-"2. The decrease will be lowest for nitrogen oxides, viz. about 40%. Analogous data for local heating sources in towns would be 10"-"5 for sulfur dioxide, 10"-"4 for particulate matter, 10"-"3 for carbon monoxide and ...
A method for determining the reactivity of subcritical systems of fissile material, using neutron-noise power spectral density measurements in conjunction with a /sup 252/Cf source, has been tested in experiments with an aqueous solution containing uranium fluoride (4.95 wt% /sup 235/U). The kappasub(eff)-values obtained from the ratio of spectral densities G*/sub 12/G/sub 13//G/sub 11/G/sub 23/ agreed with those from break-frequency noise analysis and with bias-corrected transport theory calculations within the statistical uncertainty of the measurements. Corrections for the effects of spatial modes and source-detector locations appear to be well-understood, since measurements for a variety of source-detector positions resulted in essentially the same kappasub(eff)-values. Modal correction factors were such that ignoring them would result in higher values of kappasub(eff) than actually occur. The measurements have ...
The BNL Neutral Beam Development Group has been active in the program for the development of high energy, high power neutral beam systems since 1973. These injectors are based on the production, acceleration and neutralization of negative hydrogen or deuterium ions and are supposed to be used for plasma heating and current drive in the next generation of fusion devices. Over the span of 10 years the group has studied plasma-surface type of negative hydrogen ion sources, transport and acceleration of negative ion beams and neutralization of negative ions in gases and plasmas. As the required source parameters (current, pulse length, efficiency) were changing over this period of time, the group developed several types of sources, resulting finally in the design of a steady state device operating with an excellent gas efficiency and having the possibility of scaling-up to the size necessary for a high power neutral beam ...
Jordan is an example of a third world country that is non-oil producing but contains huge reserves of other energy sources such as tar sand, oil shale, and olive cake. Some limited research is available about how to utilize these energy sources in pure form. However, available research does not deal with combinations of these energy sources. This experimental study investigates combinations of these energy forms as potential energy sources in Jordan. The experimental procedure involves characterization of samples by proximate analysis, calorific value determination of different combinations, and a compacting process of the different particles. The best combination, with respect to calorific value, is found to be 20% tar sand, 20% olive cake, and 60% oil shale. Compacting materials either with starch or with heated tar sand up to 110{sup o}C for 1 h indicates a feasible process for handling, packaging, ...
Plutonium-containing compounds vary widely in isotopic content, and as a result, the dose as function of isotopic content also varies considerably. Determination of the dose from neutrons, decay and capture gammas from plutonium in the form of compounds thus requires that the spontaneous fission and ({alpha},n) source and spectra from each individual isotope be known. To facilitate dose calculations from plutonium-containing compounds, we have calculated the spontaneous fission and ({alpha},n) sources and spectra for 1 g of each of the plutonium isotopes in the form of either PuF{sub 4} or PuO{sub 2}. As {sup 241}Am is often a component in a mixture of plutonium isotopic compounds, the source and spectra from 1 g of {sup 241}Am mixed with PuF{sub 4} or PuO{sub 2} has also been determined. Using these results, the neutron source and spectra may be determined for any sample composition. 2 refs., 3 tabs.
This thesis consists of an introduction and five included papers. Of these, four papers are published in international journals and the fifth was submitted for review in April 2000. Emphasis has been placed on both naturally and artificially generated light hydrocarbons in petroleum fluids and their proposed source rocks as well as direct application of light hydrocarbons to oil/source rock correlations. Collectively, these papers describe a strategy for interpreting the source of the light hydrocarbons in original oils and condensates as well as the source of the asphaltene fractions from the reservoir fluids. The influence of maturity on light hydrocarbon composition has also been evaluated. The papers include (1) compositional data on the light hydrocarbons from thermal extracts and kerogen pyrolysates of sediment samples, (2) light hydrocarbon data of oils and condensates as well as the pyrolysis ...
The results of the 2006 investigation of contaminant sources at Navarre, Kansas, clearly demonstrate the following: {sm_bullet} Sources of carbon tetrachloride contamination were found on the Navarre Co-op property. These sources are the locations of the highest concentrations of carbon tetrachloride found in soil and groundwater at Navarre. The ongoing groundwater contamination at Navarre originates from these sources. {sm_bullet} The sources on the Co-op property are in locations where the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) never conducted grain storage operations. {sm_bullet} No definitive sources of carbon tetrachloride were identified on the portion of the current Co-op property formerly used by the CCC/USDA. {sm_bullet} The source areas on the Co-op property are consistent with the locations ...
A new generation of quasimonochromatic high-flux X-ray sources, based on the X-ray radiation produced through Compton scattering between an electron beam and a laser beam, is under development. One of the possible applications of this source is inline phase contrast mammography, based on the observation of the edge-enhancement effect that can be observed at the border of structures inside the breast in images produced using a partially or totally coherent X-ray beam. In this work we present the results of a set of simulations of inline phase contrast mammography using typical inverse Compton scattering sources parameters. The simulated sample was a tumour-like mass having spherical shape, diameter between 200 {mu}m and 5 mm, placed inside a breast-like matrix, 4 cm thick, and a standard composition of 50% glandular tissue and 50% adipose tissue. We discuss the minimum requirements for mammography using inverse Compton ...
The lakes formed in the Amazon floodplain play a key role in sustaining the highest populational density in the Amazon Basin because of its high primary productivity. The water volume in these lakes vary greatly during the year and possible water sources are the feeding river during high water state of the hydrographs and local inputs from its drainage basin. As these sources are chemically distinct, to understand the nutrient dynamics in these lakes, it is very important to know the relative water contribution of different water sources. In this paper we use "1"8O as a conservative to know the water sources for the lakes and our hypothesis is that: 1) In the high water stage lake water is derived predominantly from its feeding river. Therefore their #delta#"1"8O should be similar. 2) In the low water stage lake water is a mixture of watershed and last flood event waters. In this case, lake #delta#"1"8O ...
The genetic type, source and charging history of natural gas in the Yulin gas field in the Ordos Basin have been studied by combining the carbon isotopic composition of natural gas and geochemical characteristics of light hydrocarbons with carbon isotope fractionation model results and fluid inclusion analysis. The carbon isotopic composition of methane and ethane in the Yulin gas field is relatively enriched in {sup 13}C with {delta}{sup 13}C{sub 1} values ranging from - 35.3 permille to - 29.8 permille (average value = - 32.4 permille) and {delta}{sup 13}C{sub 2} ranging from - 26.3 permille to - 23.5 permille (average value = - 24.8 permille). The C{sub 7} light hydrocarbons are predominated by methylcyclohexane, accounting for 65.8% to 80.9% (average value = 71.6%), which is characteristic of coal-derived gas. Furthermore, the gas geochemistry indicates that, although marine limestone source rocks are present in the region, the contribution ...
Renewable energy technologies such as photovoltaics, solar thermal power plants, and wind turbines are nonconventional, environmentally attractive sources of energy that can be considered for electric power generation. Many of the areas with abundant renewable energy resources (very sunny or windy areas) are far removed from major load centers. Although electrical power can be transmitted over long distances of many hundreds of miles through high-voltage transmission lines, power transmission systems often operate near their limits with little excess capacity for new generation sources. This study assesses the available capacity of transmission systems in designated abundant renewable energy resource regions and identifies the requirements for high-capacity plant integration in selected cases. In general, about 50 MW of power from renewable sources can be integrated into existing transmission systems to supply local loads ...
The subcriticality of two interacting solution tanks was determined using /sup 252/Cf-source-driven neutron noise analysis methods. These experiments were the first test of this method for an interacting system with materials (in this case, uranyl nitrate) typical of nuclear materials in processing plants. The experiments were performed to test the conclusions from previous interaction experiments with uranium metal discs for a fissile system with moderation, and to provide data to test theoretical models for coupled systems. The uranium metal experiments showed that the subcritical neutron multiplication factor, k/sub eff/, could be determined using point kinetics without any correction for spatial effects from measurements with the source and detectors located adjacent to the same cylinder, whereas for source-detector configurations with either the source and/or detectors adjacent to different ...
Purpose: The purpose of this course is to review the physical principles underlying design, clinical application and execution of interstitial and intracavitary implants in the classical low dose-rate (LDR) range. This year, the course will focus on quality assurance of sources, applicators and treatment planning software. In addition, development of procedures and QA checks designed optimize treatment delivery accuracy and patient safety during each individual procedure will be reviewed. The level of presentation will be designed to accommodate both physicists and physicians. Implementation of recently published AAPM Task Group reports (no. 40, 'Comprehensive Quality Assurance' and No. 43, 'Dosimetry of Interstitial Brachytherapy Sources') will be reviewed. Outline: (A) General Principles (1) QA endpoints: temporal accuracy, positional accuracy, dose delivery accuracy, and safety of the patient, personnel, and the institution (2) QA procedure ...
Power source requirements for the military were presented to provide guidelines for research and development planning. Power sources that contain a high amount of energy and are small, light and durable are a common request from military users. Safety, reliability and low temperature performance are also important factors in the selection of power sources, as are cost and energy efficiency. Issues concerning advanced batteries were reviewed with reference to high energy density cathode materials. Various thermoelectric and renewable energy materials were discussed, with reference to recovery and conversion of waste heat. It was suggested that photovoltaic devices could help revolutionize military logistics by modifying energy re-supply requirements. Solid Oxide Fuel Cells (SOFC) were considered in relation to the high price of the ceramic materials required for operation. It was noted that the development of SOFC anodes ...
The feasibility was evaluated using MCNP-DSP, an analog Monte Carlo transport cod to simulate source-driven measurements. Models of an isolated Westinghouse 17x17 PWR fuel assembly in a 1500-ppM borated water storage pool were used. In the models, the fuel burnup profile was represented using seven axial burnup zones, each with isotopics estimated by the PDQ code. Four different fuel assemblies with average burnups from fresh to 32 GWd/MTU were modeled and analyzed. Analysis of the fuel assemblies was simulated by inducing fission in the fuel using a {sup 252}Cf source adjacent to the assembly and correlating source fissions with the response of a bank of {sup 3}He detectors adjacent to the assembly opposite the source. This analysis was performed at 7 different axial positions on each of the 4 assemblies, and the source-detector cross-spectrum signature was calculated for each of ...
Lacustrine rocks are a significant component of many rift-valley sequences. Comparisons of both active and ancient rift valleys indicate that the lacustrine facies are commonly rich in organic matter and may be important sources for oil. For example, Holocene sediments in Lake Tanganyika and Cretaceous lacustrine rocks in west Africa contain as much as 12% and 20% TOC, respectively. The Newark Supergroup contains abundant lacustrine rocks. The widespread occurrence of black shales, the general similarity to known organically rich rift systems, and a few isolated geochemical analyses have caused some speculation about the potential of the Newark Supergroup to be an effective source of oil and gas. Sufficient geochemical analyses are available from lacustrine rocks in the Newark, Connecticut, and Deep River basins to evaluate their potential as hydrocarbon sources. In general, both the quantity and quality of organic matter ...
In this experiment, we measured the detection efficiency of gamma-scanning system of Irradiated Materials Examination Facility (IMEF) in Korea Atomic Energy Research Institute(KAERI) for the spent PWR fuel and activity known sources with high activity. We measured the absolute detection efficiency of gamma scanning system of IMEF to the {sup 137}Cs-source with 10.4 GBq and {sup 60}Co source with 25.9 GBq High-activity sources as standard sources, and a fuel burned in the KORI -1 reactor of the Kori Nuclear power plant. In analyzing, we used three peeks those were the 661.64 keV peak form {sup 137} Cs 1173.23 and 1332.51 keV{sup 60} Co sources, and 14 peaks of {sup 134}Cs and {sup 154}Eu on the spent fuel gamma spectrum which are in the energy range from 500 to 1,600 keV. We find second order equations for detection efficiency by using our experimental results. ...
In this experiment, we measured the detection efficiency of gamma-scanning system of Irradiated Materials Examination Facility (IMEF) in Korea Atomic Energy Research Institute(KAERI) for the spent PWR fuel and activity known sources with high activity. We measured the absolute detection efficiency of gamma scanning system of IMEF to the "1"3"7Cs-source with 10.4 GBq and "6"0Co source with 25.9 GBq High-activity sources as standard sources, and a fuel burned in the KORI -1 reactor of the Kori Nuclear power plant. In analyzing, we used three peeks those were the 661.64 keV peak form "1"3"7 Cs 1173.23 and 1332.51 keV"6"0 Co sources, and 14 peaks of "1"3"4Cs and "1"5"4Eu on the spent fuel gamma spectrum which are in the energy range from 500 to 1,600 keV. We find second order equations for detection efficiency by using our experimental results. The equation show ...
We have observed the CH_3OH J = 2-1, SiO J = 2-1, C"3"4S J = 2-1, H"1"3CO"+ J = 1-0, HN"1"3C J = 1-0, CCH N = 1-0, OCS J = 8-7, and SO J_N = 2_2-1_1 lines toward 20 massive clumps, including Midcourse Space Experiment (MSX) 8 #mu#m dark sources (infrared dark clouds) and MSX 8 #mu#m sources, by using the Nobeyama Radio Observatory 45 m telescope. We have found that the velocity widths of the CH_3OH and C"3"4S lines are broader than those of the H"1"3CO"+ line in the MSX dark sources. On the other hand, they are comparable to the velocity width of the H"1"3CO"+ line in the MSX sources. In addition, the [SiO]/[H"1"3CO"+] abundance ratio is found to be enhanced in the MSX dark sources in comparison with the MSX sources. These results suggest that shocks caused by interaction between an outflow and an ambient dense gas would have substantial impact on the chemical ...
The inner part of a fusion reactor will have to operate at very high neutron loads. In steady-state reactors the minimum fluence before the scheduled replacement of the reactor core should be at least l0-15 Mw.yr/m2. A more frequent replacement of the core is hardly compatible with economic constraints. A most recent summary of the discussions of these issues is presented in Ref. [l]. If and when times come to build a commercial fusion reactor, the availability of information on the behavior of materials and components at such fluences will become mandatory for making a final decision. This makes it necessary an early development and construction of a neutron source for fusion material and component testing. In this paper, we present information on one very attractive concept of such a source: a source based on a so called Gas Dynamic Trap. This neutron source was proposed in the ...
The GSD must be considered as a quantity by means of which the risk in a given population can be described exclusively in terms of genetic risk. In cases of a simultaneous increase in the rate of examinations, the GSD may lead to a misinterpretation of the population exposure, suggesting a decreasing trend, although there is an actual increase in the somatic radiation exposure. It is recommended to indicate not only the GSD but also the amount of somatic radiation exposure of the population for each specific source when comparing and evaluating radiation exposures from different sources. Although the somatically significant dose formally would be suited as a complement to the GSD, it is recommended to use the effective per caput dose equivalent. It must be pointed out that the application of the concept of effective dose equivalent is only appropriate for comparative evaluations of the population exposure to different ...
This report reviews Soviet R and D of (1) high-intensity negative ion sources and (2) transport and focusing of negative ion beams, using Soviet open literature of the past ten years, and correlates this data with data on Soviet institutes responsible for negative ion beam development. The Soviets are developing intense negative ion beams as the basis for creating neutral beams for injection into mirror traps and tokamaks, for inertial confinement fusion, and possibly for exoatmospheric beam weapon applications. The report focuses specifically on surface-plasma-type ion sources, which were first developed in the USSR and which show great promise for creating beams of high intensity, high brightness, and low emittance. Mechanisms for optimum negative ion beam transport are also discussed.
Fixation of /sup 14/CO/sub 2/ and activities of sucrose-synthesizing enzymes, sucrose phosphate synthetase (SPS) and sucrose synthase (SS), were assayed in tissues of developing fruit and source leaves from Citrus paradisi Macf. SPS activity of both the outer, chlorophyllous layer of the fruit (flavedo) and source leaves was 10-fold greater than that of the inner, largely non-chlorophyllous layer of the fruit peel (albedo). In contrast, SS activity of the flavedo was 2-fold greater than that of the albedo and 10-fold greater than that of leaves. Fixation of /sup 14/C-photosynthates in isolated tissues (flavedo 2x > albedo) and their redistribution in intact fruit indicated that flavedo functions as both source and sink. Activities of sucrose-synthesizing enzymes were consistent with this dual function.
We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities > 100 mJy at 500 um, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 um data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with Av ~4 to 5 and star formation rates of ~100 M_sun/yr. They have low gas fractions and low dynamical masses compared to 850 um selected galaxies.
A real-time orbit feedback system has been implemented at the Advanced Photon Source in order to meet the stringent orbit stability requirements. The system reduces global orbit motion below 30Hz by a factor of four to below 5{micro}m rms horizontally and 2{micro}m rms vertically. This paper focuses on dynamic orbit stability and describes the all-digital orbit feedback system that has been implemented at the APS. Implementation of the global orbit feedback system is described and its latest performance is presented. Ultimately, the system will provide local feedback at each x-ray source point using installed photon BPMs to measure x-ray beam position and angle directly. Technical challenges associated with local feedback and with dynamics of the associated corrector magnets are described. The unique diagnostic capabilities provided by the APS system are discussed with reference to their use in identifying sources of the ...
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 and radiation physics, and the mathematics has been limited to elementary ...
The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.
Ion beams of halogens can be produced either positively or negatively charged, depending on the employed ion source. At CERN-ISOLDE, although positively charged fluorine and astatine can be obtained from a hot plasma ion source, they are often contaminated by isobars and molecular sidebands. This has generated a request from the scientific community for fluorine and astatine negative ion beams free of contaminants. The high selectivity ensured by the surface ionisation process also makes negative beams of chlorine, bromine and iodine highly attractive. However, the efficiency figures for negative surface ionisation of fluorine and astatine were lower than the ones from the hot plasma. Here we report our R and D on new surface ion sources suitable for the production of negative halogen beams.
The proposal made in this paper refers to a free electron laser FEL with small-period electromagnet undulator in SASE regime and a FEL transverse optical klystron in the amplifier regime. The relativistic electron beam source for this FEL is the 7 MeV electron linac of the National Institute for Laser, Plasma and Physics Radiation (NILPRP) in Bucharest. The paper presents the main features of the design and performance of both FELs and discusses the improvements which must be made to the accelerator in order to use it as a free electron source concerning the injection system of electrons and formation of accelerated electron beam. The findings show that this FEL can be employed as a coherent radiation source in the IR range. (author)
A new process engineering flowsheet reflecting an improved design of the LASL Bismuth Sulfate thermochemical cycle is presented. The design is based on laboratory data that indicate a lowered endothermic heat load for a partial decomposition of the solid bismuth sulfate. A small electrical energy demand should result from operation of the sulfur dioxide electrolytic step at lower acid concentration, in principle. The results of the flowsheeting analysis yield a thermal efficiency of 50% for the cycle when coupled to a conceptual fusion energy heat source at 1500/sup 0/K. A parametric analysis shows a slight drop in efficiency as the temperature of the heat source is decreased. The LASL Bismuth Sulfate thermochemical cycle appears to have potential as a means of producing hydrogen from high-temperature heat sources such as fusion, fission, and solar energy; it also appears to be competitive with alternative thermochemical ...
Measurements of neutron and gamma-ray penetrations in an iron shield were performed up to a 60-cm depth in a tightly coupled source shield configuration with the fast-neutron reactor YAYOI as a source. Rates of neutron reactions and gamma-ray dose rates in the iron shield were obtained using activation foils and thermoluminescent dosimeters. Analyses of the experiments were made by using the DOT-III code with coupled neutron and gamma-ray cross sections from ENDF/B-IV and POPOP4 libraries. To obtain the source condition for the iron shield analyses, the calculated spectrum was adjusted to the measured reaction rates at the reactor shield boundary. The calculated neutron and gamma-ray distributions in the iron shield show fairly good agreement with the experiments. The effect of difference in Bondarenko-type self-shielding factors on the analyses of the iron shield is also shown.
During the 1990's, natural gas was the energy source with the fastest rate of growth in the world energy balance. Nevertheless, recent evolutions of the energy context, in particular in terms of prices, have had a rather strong impact on the progress of the different energy sources penalizing gas a little. Beyond this competition between energies, which may increase, the medium-term perspectives of natural gas development is in keeping with an environment full of uncertainties. This article presents: the world supply and demand prospects for 2010-2015 (impact of high gas prices on other energy sources, occurrence of production constraints, political decisions of producing countries and world gas industry balance), trends on main markets (North America, Europe, Asia-Oceania), and international trade. (J.S.)
Kundur [Benincasa hispida (Thunb.) Cogn.], a member of the family Cucurbitaceae, is one of the famous crops that are grown primarily for its fruits and usually recognized with its nutritional and medicinal properties especially in Asian countries. Kundur fruit has been valued as a nutritious vegetable as it provides a good source for natural sugars, amino acids, organic acids, mineral elements and vitamins. A number of medicinal properties such as anti-diarrheal, anti-obesity, anti-ulcer, and antioxidant and diuretic have been ascribed to this fruit of high economic value. As a rich source of functionally important bioactives and therapeutics such as triterpenes, phenolics, sterols, and glycosides, the fruit has been widely used for the treatment of epilepsy, ulcer, and other nervous disor...
Background: The Internet has become a popular source of health information for patients with a variety of medical concerns; however, research examining patient interactions on the Internet has been limited. Purpose: Four questions were examined in a survey study of hysterectomy patients who visited http://www.hystersisters.com: (a) Do hysterectomy patients use the support Web site because they perceive their proximal sources of social support to be inadequate? (b) What kinds of support do patients receive from the Web site? (c) What attributes characterize the "Hystersisters" that are perceived to be most helpful? (d) How do informational sources vary depending on the nature of the patient concern? Methods: Women (N = 137) responded to questions about social support, Web site use, and perc...
PSI has a relatively long tradition in neutron imaging since the first trials were done at its formerly existing research reactor SAPHIR with film methods. This reactor source was replaced after its shutdown in 1994 by the spallation neutron source SINQ in 1996, driven by the 590MeV cyclotron for protons with presently up to 2.3mA beam current. One of the first experimental devices at SINQ was the thermal neutron imaging facility NEUTRA, which was designed from scratch and has been the first device of its kind at a spallation source. Until now, NEUTRA has been successfully in use for many investigations in a wide range of studies covering fuel cell research, environmental behavior of plants, nuclear fuel inspection and the research on cultural heritage objects. It has been the host of PhD ...
Entanglement swapping allows to establish entanglement between independent particles that never have interacted nor share a common past. This feature makes it an integral constituent of quantum repeaters and a promising tool for future tests of the foundations of quantum physics. Here, we demonstrate entanglement swapping with time-synchronized independent sources with a fidelity high enough to violate a Clauser-Horne-Shimony-Holt (CHSH) inequality by more than four standard deviations. The fact that both entangled photon pairs are created by fully independent laser sources, which are only electronically connected, ensures that this technique is suitable for future long-distance entanglement swapping and quantum-repeater experiments.
Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in ...
Orbit correction is now routinely performed at the few-micron level in the Advanced Photon Source (APS) storage ring. Three diagnostics are presently in use to measure and control both AC and DC orbit motions: broad-band turn-by-turn rf beam position monitors (BPMs), narrow-band switched heterodyne receivers, and photoemission-style x-ray beam position monitors. Each type of diagnostic has its own set of systematic error effects that place limits on the ultimate pointing stability of x-ray beams supplied to users at the APS. Limiting sources of beam motion at present are magnet power supply noise, girder vibration, and thermal timescale vacuum chamber and girder motion. This paper will investigate the present limitations on orbit correction, and will delve into the upgrades necessary to achieve true sub-micron beam stability.
An apparatus for non-invasively inspecting an object, such as an item of luggage, for explosives material is described. It comprises a multi-channel thermal neutron inspection system having a plurality of neutron irradiation chambers. Simultaneous operation of several channels increases the maximum system throughput several times. Each chamber has a lithium neutron source which is stimulated to neutron production by a proton beam. Beam switching magnets are energised by pulsing to divert a common proton beam to each source in turn. The initial beam is generated by a radio frequency quadrupole accelerator. The advantages of this system are very low residual source activity and controllable neutron production thereby minimising safety hazards. The irradiation chamber may contain several different gamma ray detectors to identify the elements present in explosives material. In addition, a neutron radiography imaging means may ...
Objective:EEG source imaging provides important information regarding the underlying neural activity from noninvasive electrophysiological measurements. The aim of the present study was to evaluate source reconstruction techniques by means of the intracranial electrocorticograms (ECoGs) and functional MRI.Methods:Five source imaging algorithms, including the minimum norm least square (MNLS), LORETA with Lp-norm (p equal to 1, 1.5 and 2), sLORETA, the minimum Lp-norm (p equal to 1 and 1.5; when p=2, the MNLS method is mathematically equivalent to the minimum Lp-norm) and L1-norm (the linear programming) methods, were evaluated in a group of 10 human subjects, in a paradigm with somatosensory stimulation. Cortical current density (CCD) distributions were estimated from the scalp somatosensor...
The development and occurrence of new electron accelerators and applications are according to the human society development law, as a whole. The period of economic standstill is generating an intense creative activity in the domain of science and engineering which also resulting in great achievements in the field of electron accelerators. This paper presents the basic principle of the electron beam applications and the accelerators required characteristics for their present and potential applications in the domains: radiation sources, diagnostics, radiation processing, energetics, environment, defense and basic sciences. All these are correlated to the new generation of accelerators which, for the acceleration process, may employ electromagnetic fields generated by standard sources, atomic lasers, free electron lasers, Cerenkov effect, Smith - Purcell effect, electron beams, plasma, excited atoms into a crystal or other ...
With the combination of source ventilation and ceiling cooling for air-conditioning of working and recreation rooms, a ventilation system is available which fulfills the highest demands regarding thermal comfort. In order to utilize the advantages of this ventilation system with regard to air quality and thermal comfort to an optimum, the influence of the radiation exchange between cooling ceiling and walls on the flow in the room is investigated experimentally. Energy transfer from the walls to the cooled ceiling may result in an insufficient temperature of the walls compared to ambient air and in an upward flow on the wall surfaces (downward flow of) driven by gravity, which influences the flow pattern in the case of source ventilation. (orig.)
The report identifies and analyzes the economic impacts of water pollution control regulations on the battery manufacturing industry. These regulations include effluent limitations and standards based on BPT (best practical control technology currently available), BAT (best available technology economically achievable), PSES (pretreatment standards existing sources), NSPS (new source performance standards), and PSNS (pretreatment standards new sources), that have been promulgated under authority of Sections 301, 304, 306, 307, 308, and 501 of the Federal Water Pollution Control Act, as Amended (the Clean Water Act). The primary economic impact variables of interest include price changes, plant closures, substitution effects, changes in employment, shifts in the balance of foreign trade, changes in industry profitability, structure, and competition, and impacts on small business.
To investigate the 2D/1D fusion core analysis method, a 1D neutron transport problem solver, PEACH-ID, is developed. It is a code of method of characteristics (MOC), both the usual fiat-source step characteristics (SC) scheme and linear source (LS) approximation scheme are adopted for tracking calculation along the neutron flying trajectory. Exponential function interpolation table and fission source extrapolation are adopted as two major methods to accelerate the computational process. Numerical results demonstrate that PEACH-1D is accurate and efficient, and the proposed LS scheme is able to handle quite larger mesh division and deserves much more application in the MOC codes. (authors)
The coupled neutron-gamma cross section libraries BUGLE-80 and SAILOR are compared, with focus on gamma production and transport and its sensitivity to the thermal component of the neutron flux. In addition, the importance of the prompt versus delayed components of the gamma source is addressed. Although BUGLE-80 shows some discrepancies in the core region, the two libraries demonstrate similar capability in the vicinity of the pressure vessel and beyond. The delayed fission product gammas from the core have little impact on the local gamma fluxes beyond the pressure vessel. Although thermal neutron capture is the dominant component of the gamma source, there is little sensitivity of the gamma source to uncertainties in the thermal neutron cross sections, due to compensating effects which tend to keep the thermal neutron capture rate relatively constant.
The emittances of hydrogen and deuterium negative ion beams produced by volume ion sources have been measured in a transverse plane normal to the beam trajectory. The extraction voltage was varied from 10 to 40 kV, and the transverse magnetic field in the Penning discharges was varied from 0.1 to 0.2 T. Measurements were made on beams with current densities up to 60 mA/cm/sup 2/ at Oak Ridge National Laboratory with an emittance scanner originally developed at Los Alamos National Laboratory. The beam profile at the scanner can be used to improve the accuracy of the emittance measurements. Other factors affecting emittance measurements are discussed. This analysis may be applicable to other ion sources. 6 figs.
This chapter consists of some points including an introduction, the basic parts of mass spectroscope device, sample introduction into the inductively coupled plasma, pneumatic nebuliser, ultrasonic nebuliser, dry gas cloud system, laser ablation unit, inductively coupled plasma-ion source, extraction of ions from ion source, mass analysis, quad-polar mass spectrometer, dual assembly mass spectrometer, mass spectrometer by calculation of time of flight, ion interferences and the ability of resolution, ion counter, working conditions of inductively coupled plasma mass spectroscope device, efficiency of ion transportation in an inductively coupled plasma mass spectroscope device and applications of analysis using mass spectroscope of induced plasma including nuclear, industrial, geological, environmental and archaeological applications, measurement of isotopes ratio and applications in tracing crimes.
The /sup 252/Cf-source-driven noise analysis method determines the subcriticality of a system containing fissionable material from the ratio of cross power spectral densities between the detectors that detect particles from the fission process and between these detectors and an ionization chamber containing a spontaneously fissioning neutron source which provides neutrons to induce fission in the system. This method has two advantages: (1) a calibration is not required and thus subcriticality can be determined from measurements only on the subcritical system of interest, and (2) the subcriticality is independent of the type of detector or its efficiency. These properties of this technique are illustrated by measurements.
The problem of passively tracking a moving signal source has importance in a variety of applications such as radar, sonar, seismology, and radio astronomy. In many applications, only limited information is available about the signal source. It will be assumed here that only the signals which are detected by the sensors and the velocity of the source signal are known. The objective of this document is to present a program which passively tracks a target using an array of sensors. This program is available in MATLAB, version 3.5. The algorithm which is implemented consists of three main parts: time delay estimation, passive localization, and data post processing. Each of these parts are discussed, and the mathematical foundation for their solution given. Following, this the organization of the program is presented, and an example of its usage is given.
An analytical method was proposed for calculating radiative fluxes incident on a planar circular detector from a volume multiple point chemi- or bio-luminescent source inside a coaxial cylindrical reactor. The method was designed for a cylindrical reactor when the surface reflections were neglected and when chemi- or bio-luminescence reaches a detector embedded in the same homogeneous optical medium as the point emitters of the volume multiple point source model. The radiative fluxes from arbitrarily distributed point emitters were expressed by one generalized quadruple-integral formula. Then some double- and single-integral formulas were obtained for calculating radiative fluxes from identically radiating point emitters uniformly distributed within the reactor. Selected results were compu...
This work addresses the problem of estimating the direction-of-arrival (DOA) of two sources using an array of sensors. This problem is mostly useful in radar applications, where we have few targets at each range bin. Super-resolution algorithms, such as maximum likelihood (ML) estimation and multiple signal classification (MUSIC), have been applied to this problem, but the former involves high computation efforts, while the later has poor estimation performance for coherent sources. In this work, we propose a DOA estimation network, named RBF-AML, which combines the approximated ML (AML) estimator and a radial basis function (RBF) neural network (NN). In the proposed RBF-AML network, the entire two dimensional DOA space is divided into multiple sectors covered by RBF experts. The AML funct...
Suppose an astronomer is equipped with a device capable of detecting emissions -- whether they be electromagnetic, gravitational, or neutrino -- from transient sources distributed throughout the cosmos. Because of source rate density evolution and variation of cosmological volume elements, the sources first detected when the machine is switched on are likely to be ones in the high-redshift universe; as observation time increases, rarer, more local, events will be found. We characterize the observer's evolving record of events in terms of a "probability event horizon", converging on the observer from great distances at enormous speed, and illustrate it by simulating neutron star birth events distributed throughout the cosmos. As an initial application of the concept, we determine the approach of this horizon for gamma-ray bursts (GRBs) by fitting to redshift data. The event rates required to fit the model are consistent with ...
Experiments with fresh PWR fuel assemblies were performed to assess the {sup 252}Cf-source-driven frequency analysis method for measuring the subcriticality of spent fuel. The measurements at the Babcox and Wilcox Critical Experiments Facility mocked up between 17x17 fuel pins (single assembly) and a full array of 4961 fuel pins (about 17 fuel assemblies) in borated water with a fixed B concentration. For the full array, the B content of the water was varied from 1511 at delayed criticality to 4303 ppM. Measurements were done for various source-detector-fuel pin configurations; they showed high sensitivity of frequency analysis parameters to B content and fissile mass. Parameters such as auto and cross power spectral densities can be calculated directly by a more general model of the Monte Carlo code (MCNP-DSP). Calculation-measurement comparisons are presented. This model permits the validation of neutron and gamma ray transport calculational ...
An atom-by-atom understanding of life processes is emerging from a flurry of experiments fueled by synchrotron sources and DNA technology. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}.
Coupled rat heart mitochondria produce externally hydrogen peroxide at the rates which correspond to about 0.8 and 0.3 per cent of the total oxygen consumption at State 4 with succinate and...Full Text Available
San Francisco Bay has been contaminated historically by mercury from mine tailings as well as contemporary industrial sources. Native Spartina foliosa and non-native S....Full Text Available
OBJECTIVE: To use Medicaid claims data to construct patient origin-based market areas for dental services and compare constructed market areas with those based on the practice county. DATA SOURCES:...Full Text Available
Strain F, a recently isolated ruminal bacterium, grew rapidly with glutamate or glutamine as an energy source in the presence but not the absence of Na. Monensin, a Na+/H+ antiporter, completely inhibited...Full Text Available
BackgroundInterim analysis of accumulating trial data is important to protect participant safety during randomized controlled trials (RCTs). Data Monitoring Committees (DMCs) often...Full Text Available
The rate of appearance of unlabelled glucose was calculated from tracer data and compared with the actual rate of infusion of unlabelled glucose into a anaesthetized dog with all sources of endogenous...Full Text Available
1. l(+)-Methionine sulphoxide has been isolated for the first time from a natural source, the blowfly Phormia regina. 2. The natural compound is shown to be identical with...Full Text Available
OBJECTIVE. This study examines variations in the efficient use of hospital resources across individual physicians. DATA SOURCES AND SETTING. The study is conducted over a two-year period (1989-1990)...Full Text Available
We present a detailed spectral analysis of point-like X-ray sources in the XMM-COSMOS field. Our sample of 135 sources only includes those that have more than 100 net counts in the 0.3-10 keV energy band and have been identified through optical spectroscopy. The majority of the sources are well described by a simple power-law model with either no absorption (76%) or a significant intrinsic, absorbing column (20%).As expected, the distribution of intrinsic absorbing column densities is markedly different between AGN with or without broad optical emission lines. We find within our sample four Type-2 QSOs candidates (L_X > 10^44 erg/s, N_H > 10^22 cm^-2), with a spectral energy distribution well reproduced by a composite Seyfert-2 spectrum, that demonstrates the strength of the wide field XMM/COSMOS survey to detect these rare and underrepresented sources.
The purpose of this study was to examine relationships between weather and outdoor physical activity (PA). An online weather source was used to obtain daily max temperature [DMT], precipitation, and...Full Text Available
Background Microbial water-quality indicators, in high concentrations in sewage, are used to determine whether water is safe for recreational purposes. Recently, the use of these indicators...Full Text Available
These sky images are scanned for point sources above a specified ... The threshold criteria are: a) Gold: >4 sigma in both the Soft AND Hard bands. b) Silver: ... Filtering: Currently, there is no plan for filtering within the GCN based ...
tial/angular spreading of incident photons from a point source caused by the instrument (de- .... Filter. CDTP0001= 'DATA. ' / Type of calibration. CCNM0001= '2D_PSF ' ... the final resolution of sigma=0.5 arcmin in all energy bands. ...
Y{sub 2-x}Tb{sub x}SiO{sub 5} and Y{sub 2-x}Eu{sub x}SiO{sub 5} nanophosphors with seven different kinds of silicate sources were synthesized by sol-gel method. The structures have been investigated to be composed of nanometer-size grains of 30-60 nm through X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used to compare the different morphology of patterns from seven different silicon sources. The photoluminescence of Y{sub 2-x}Tb{sub x}SiO{sub 5} was investigated as a function of silicate sources and the results revealed that these nanometer materials showed the characteristic emission {sup 5}D{sub 4} {yields} {sup 7}F{sub J} (J 6, 5, 4, 3) of Tb ions. The characteristic emission {sup 5}D{sub 0} {yields} {sup 7}F{sub J} (J = 1, 2, 4) of Eu ions was also found in the materials of Y{sub 2-x}Eu{sub x}SiO{sub 5}.
Apr 20, 2009 ... "YY" is the 2-digit filter identifier .... In our example you can see a point- like optical/UV source in each of the filters at the ... The "sigma" paramter gives the detection threshold in terms of Gaussian sigma. ...
This paper describes recent measurements of the subcritical neutron multiplication factor using the /sup 252/Cf source-driven neutron noise analysis method. This work was supported by a program of collaboration between the United States Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan related to the development of fast breeder technology. The experiment reported consists of a configuration of two interacting tanks of uranyl nitrate aqueous solution with different uranium concentrations in each tank. The /sup 252/Cf-source-driven neutron noise analysis method obtains the subcriticality from the signals of three detectors: the first, a parallel plate ionization chamber with /sup 252/Cf electroplated on one of its plates that is located in or near the system containing the fissile material, and produces an electrical pulse for every spontaneous fission that occurs and thereby serves as a timed ...
The pollutants from the exhausts of internal combustion engines cause a range of illnesses and are the main source of atmospheric contamination. This article explores the options for curbing pollution in the UK including catalytic converters, electric cars, and natural gas cars. It is likely that the onus will remain with the car manufacturers for developing solutions. (UK)
This paper discussed issues related to the storage of electricity produced from renewable energy sources. Storage systems currently used by distribution systems were reviewed. The study showed that successful storage systems ensure high charging and discharging rates for shorter periods of time. Systems with high storage capacities must also be able to store energy for longer periods of time than traditional energy storage systems. Systems include pumped storage plants; electro-chemical accumulators; compressed air accumulators; and redox flow batteries. Hydrogen technologies for the storage of electric energy from renewable sources were reviewed. The paper also outlined energy storage and fuel cell research currently being conducted by researchers in the Czech Republic. The study concluded by stating that new energy storage technologies are required to ensure the reliability of electricity produced from renewable energy ...
This paper highlights some of the conceptual and methodological problems involved in the compilation of statistics on economic aid to developing countries. Figures from the OECD Development Assistance Committee (DAC) and the Organization of Petroleum Exporting Countries (OPEC) member states are compared to point up problems in the interpretation of the statistics. One area of concern is the listing of funds provided by financial institutions located in the DAC countries. OPEC capital often forms a majority of such institutions; yet the figures do not measure the OPEC share of the capital nor its share of the risk borne in its provision of the loans. Another area of concern is bond purchases and subscriptions to syndicated loans by OPEC financial institutions in the financial markets of DAC countries. The flows in these instances, originating from OPEC sources, are merely channeled through the DAC financial markets. Based on origin and risk (borne exclusively by ...
Beta silicon carbide is an excellent candidate semiconductor material for demanding applications in high power and high temperature electronic devices due to its high breakdown voltage, relatively large band gap, high thermal conductivity and high melting...
The e.p.r. spectra of the Fe-proteins of nitrogenase from all sources studied have unusual features in that they have very anisotropic linewidths and low integrated intensities. These characteristics...Full Text Available
The most publicly justifiable application of human cloning, if there is one at all, is to provide self-compatible cells or tissues for medical use, especially transplantation. Some have argued that...Full Text Available
The planned spallation source can be of considerable significance for biomedical basic research and for clinically relevant diagnostic and therapeutic applications. The following gives a brief description and explanations for its possible use in clinical medicine: I. Treatment of Malignant Tumors II. Production of Isotopes for Biochemical Investigations in Living Organisms for Diagnostic Purposes.
This document is a collection of spreadsheets detailing in a county by county manner the agricultural crop, agricultural wastes, municipal wastes, and industrial wastes of South Carolina that are potential biomass energy sources.
This document is a collection of spreadsheets detailing in a county by county manner the agricultural crop, agricultural wastes, municipal wastes and industrial wastes of North Carolina that are potential biomass energy sources.
Globally, sexually transmitted infections (STIs) represent a significant source of morbidity and disproportionately impact the health of women and children. The number of randomized controlled trials...Full Text Available
Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG) is an emerging field that has gained much attention in past...Full Text Available
The Executive Body adopted the Protocol on Heavy Metals on 24 June 1998 in Aarhus (Denmark). It targets three particularly harmful metals: cadmium, lead and mercury. According to one of the basic obligations, parties will have to reduce their emissions for these three metals below their levels in 1990. The Protocol aims to cut emissions from industrial sources, combustion process and waste incineration. It lays down strighten limit values for emissions from stationary sources and suggests best available techniques (BAT) for these sources, such as special filters or scrubbers for combustion sources or mercury-free processes. The Protocol requires parties to phase out leaded petrol. It also introduces measures to lower heavy metal emissions from other products, such as mercury in batteries, and proposes the introduciton of management measures for other mercury-containing products, such as electrical ...
... based, disease treatment remains promising, the emphasis for stem cell research from the biomedical research community is clear, and ... diagnosis as a novel source of embryos for stem cell research. Repr...
Sep 28, 2011 ... Source: Flagstaff, AZ: Northern Arizona University. 87 p. Thesis. Description: High severity wildfires have been increasing across southwestern ...
Various energy sources and motors of divers types can be used in electric cars with operating modes subjected to a number of particular constraints. As a result, the possible structures of the converters, that are analysed in detail, are about a dozen in number. Also considered is the use of solid-state components - thyristors, power transistors and new components.
... being reported (Kisseberth et al., 1984; Ma, 1989; Shore and Douben, 1994). Small mammals are useful indicator species because they have relatively small home ranges allowing a direct tie to the source of ...
The genus of filamentous cyanobacteria, Lyngbya, has been found to be a rich source of bioactive metabolites. However, identification of such compounds from Lyngbya...Full Text Available
Processes and apparatus are disclosed for generation of radioisotope contaminant fission fragment free ozone from oxygen containing streams by chemonuclear irradiation accomplished by passing the stream past high energy radiation sources placed in sealed chambers.
We present photoelectric BVRI photometry for 16 T Tau and related stars in the Rho Oph dark cloud, as well as vidicon spectroscopic observations for nine stars. The color excesses of these stars favor circumstellar dust shells as the source of the observed infrared excesses.
IntroductionWhile epidemiological methods have grown in sophistication during the 20th century, their application in historical occupational (and environmental) health...Full Text Available
This report focuses on air quality at the Nevada Test Site (NTS) for 1994. A general description of the effluent sources are presented. Each potential source of NTS emissions was characterized by one of the following: (1) by monitoring methods and procedures previously developed at NTS; (2) by a yearly radionuclide inventory of the source, assuming that volatile radionuclides are released to the environment; (3) by the measurement of tritiated water concentration in liquid effluents discharged to containment ponds and assuming all the effluent evaporates over the course of the year to become an air emission; or (4) by using a combination of environmental measurements and CAP88-PC to calculate emissions. Appendices A through J describe the methods used to determine the emissions from the sources. These National Emission Standards for Hazardous Air Pollutants (NESHAP) emissions are very conservative, are ...
Klebsiella oxytoca can use nitrate and nitrite as sole nitrogen sources. The enzymes required for nitrate and nitrite assimilation are encoded by the nasFEDCBA operon....Full Text Available
considers a wide range of pathways to advance the nation's current capabilities. The present ... opment of new energy sources, aging infrastruc- ture and ... and manufacturing TA strategic roadmap as brief- ..... pellant storage and transport. ...
Aluminium (Al) toxicity, affecting around half of the world¿s arable land, severely hinders the ability of crop plants to utilize moisture and nutrients by restricting root growth and function. Among the cultivated cereals, rye is the most Al-tolerant and represents an important potential source of ...
Methylosulfonomonas methylovora M2 is an unusual gram-negative methylotrophic bacterium that can grow on methanesulfonic acid (MSA) as the sole source of carbon and energy. Oxidation...Full Text Available
Transposable elements (TEs) comprise a large fraction of mammalian genomes. A number of these elements are actively jumping in our genomes today. As a consequence, these insertions provide a source...Full Text Available
OBJECTIVE. This study was conducted to determine whether an index for measuring quality of care for psychiatric emergencies is reliable and valid. DATA SOURCES/STUDY SETTING. The study used primary...Full Text Available
A Russian knapweed (Acroptilon repens) shoot culture system, initiated from shoot tip culture, was used to generate a source of host plant tissue for the rearing of the nematode Subanguina...Full Text Available
The manufacture and use of wood/plastic composite (WPC) as an example of wood matrix and wood sawdust/plastic composites (SDP) as an example of plastic matrix are reviewed. The raw material for WPC are mostly vinyl monomers, particularly methyl methacrylate and styrene. The reaction in WPC polymerization is radical polymerization. Researches on the radiation sources mostly resulted in gamma-ray. Electron beam can be applied only to thin products. The future use of WPC may be for furnitures, sporting goods, decorative parts and the like. Vital study on the reduction of manufacturing costs is required, for example, the improvement of reaction and the adoption of continuous process must be considered. The raw materials for SDP are wood sawdust, vinyl monomer (mostly methyl methacrylate) and resins. Electron beam accelerators are the most preferable radiation source because of its high efficiency and safe operation. SDP shows good forming property. ...
Sources of manganese are identified. Uptake and distribution of manganese in plants and man are discussed, and the role of manganese in metabolism is described. The epidemiology of manganese toxicity is outlined, permissible air concentrations are listed, and the symptoms of manganese toxicity and deficiency are described. 555 references, 32 tables.
Patients with haemarthros of the knee were examined by MRI and arthroscopy to identify the bleeding source and to determine surgical or conservative therapy. A prospective study was performed on 120 patients who underwent MRI and arthroscopy, point lesions and bleeding sources were documented separately on a standardised form. Arthroscopy demonstrated a ruptured anterior cruciate ligament in 86%, meniscal tears in 55%, disruption of collateral ligaments in 17%, osteochondral lesions in 5% and tears of capsule or plicae in 13%. Disruption of cruciate ligaments caused haemorrhage in all but three cases. In contrast, only meniscal tears located very adjacent to the meniscal basement had bled. Those types of osteochondral lesions caused haemorrhage characterised on MRI by destruction of the subchondral plate and overlying cartilage. Severe lesions of the knee were diagnosed by MRI in 71% to 100%, slight lesions in 13% to 40% of the cases. Single, ...
We construct a sample of low-redshift Ly-alpha emission-line selected sources from GALEX grism spectroscopy of nine deep fields to study the role of Ly-alpha emission in galaxy populations with cosmic time. Our final sample consists of 122 (142) sources selected in the redshift interval z=0.195-0.44 (z=0.65-1.25) from the FUV (NUV) channel. We classify the Ly-alpha sources as AGNs if high-ionization emission lines are present in their UV spectra and as galaxies otherwise. These classifications are broadly supported by comparisons with X-ray and optical spectroscopic observations. We classify additional sources as AGNs using line widths for our Ly-alpha emitter (LAE) analysis. Defining the GALEX LAE sample in the same way as high-redshift LAE samples, we show that LAEs constitute only about 5% of NUV-continuum selected galaxies at z~0.3. We also show that they are less common at z~0.3 than they are at ...
Summary: The small DNA tumor viruses have provided a very long-lived source of insights into many aspects of the life cycle of eukaryotic cells. In recent years, the emphasis has been on cancer-related...Full Text Available
New developments in fluorophores as well as in detection methods have fueled the rapid growth of optical imaging in the life sciences. Commercial widefield microscopes generally use arc lamps, excitation/emission...Full Text Available
A short survey of the energy situation in Iran is given with the aid of some interesting figures. Following remarks on the national and international energy policy, the developments regarding individual energy sources and electricity production are described.
Large population sizes, rapid growth and 3.8 billion years of evolution firmly establish microorganisms as a major source of the planet's biological and genetic diversity. However, up to 99% of the...Full Text Available
As the IC Information Sharing Executive (IC ISE), my main focus today concerns classified information--and, in particular, information that is derived from intelligence sources and methods, or information that is reflected in the analytic judgments and as...
Characteristics of inertia gravity waves associated with convection are investigated in the lower stratosphere using high-resolution radiosonde data observed from 18 June to 15 July of 2005 and 2007 in Korea. Three-dimensional ray-tracing model and reanalysis data are used to investigate the propagation and the sources of the observed waves. The observed waves associated with convections are discriminated based on the existence of convections when and where the rays reach the average height range of convective clouds. Waves observed in 2005 and 2007 show similar spectral characteristics, but wave energy in 2007 is significantly larger than in 2005. The observed waves propagate from three source regions: the northeastern, southeastern, and western regions around Korea. They show preferential propagation directions based on their sources, and convections from the western region generate larger-amplitude gravity waves than the ...
Water samples from several ponds in Minnesota were evaluated for their capacity to induce malformations in embryos of Xenopus laevis. The FETAX assay was used to assess the occurrence of malformations...Full Text Available
In several regions of Czechoslovakia with intensive agricultural production, the correlation between the amount of nitrogen fertilizer applied and the nitrate content in groundwater has been recognized....Full Text Available
Reichert's membrane, an extraembryonic membrane present in developing rodents, has been proposed as an in vivo model for the study of basement membranes. We have used this membrane as a source for isolation...Full Text Available
Gamma-ray burst (GRB) is one of the candidates of high-energy cosmic-ray acceleration sites. They may be also ultra-high-energy (above 3 EeV) cosmic-ray (UHECR) sources. In this paper, we discuss possibilities and implications of high-energy cosmic-ray acceleration in GRBs. (1) First, we show that not only protons but also heavier nuclei can be accelerated up to ultra-high energies in both usual high-luminosity (HL) and low-luminosity (LL) GRBs by using the Geant4. LL GRBs may also make a significant contribution to the observed UHECR flux if they form a distinct population, and we investigate cosmic-ray acceleration in LL GRBs in detail. (2) Second, we discuss implications of the GRB-UHECR hypothesis (and Hypernova-UHECR hypothesis) to cosmic-ray astronomy. HL GRBs and LL GRBs will lead to different source number densities as UHECR sources, so that the determination of the number density of UHECR ...
Sep 1, 2011 ... Title: Hardness, density, and shrinkage characteristics of silk-oak from Hawaii. Author: Youngs, R. L.. Date: 1964. Source: Research note FPL ...
Growth of Lactococcus lactis subsp. lactis biovar diacetylactis was observed on media with citrate as the only energy source. At pH 5.6, steady state was achieved in...Full Text Available
The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of...Full Text Available
Differential phase-contrast X-ray imaging has been performed in a Talbot-Lau configuration, where a multiline X-ray source was used instead of a combination of a hard-X-ray multiple slit and a normal focus X-ray generator. When the multiple slit is used, a high aspect ratio structure is needed and slit width should be below 10 ?m for its function. The fabrication and use of such a multislit can be omitted using the presented configuration. The multiline X-ray source was developed by making grooves on a tungsten rotating anode, which was irradiated by an electron beam to generate X-rays. An array of 10?m line sources with a pitch of 30?m was formed and combined with a 4.5 ?m pitch phase grating and a 5.3 ?m pitch amplitude grating to generate differential phase contrast. With a total exposure time of 40 s, a differential phase image depicting cartilages was obtained. (author)
Results are described of a study and of the characteristics of sources of a non-equilibrium gas-discharge plasma. The plasma generators considered include glow, high frequency, and arc discharge generators. Thermodynamic, ionic, and electronic processes occurring in the plasmas are evaluated.
The genetic systems of bacteria that have the ability to use organic pollutants as carbon and energy sources can be adapted to create bacterial biosensors for the detection of industrial pollution....Full Text Available
Francisella tularensis requires iron (Fe) for growth, but the biologic sources of Fe for this organism are largely unknown. We found that Francisella sp. growing in...Full Text Available
A prototype detector based on the inclined boron layer principle is introduced. For typical measurement conditions at the Liquids Reflectometer at the Spallation Neutron Source, its count rate capability is shown to be superior to that of the current detector by nearly two orders of magnitude.
A prototype detector based on the inclined absorber layer principle is introduced. For the Liquids Reflectometer at the Spallation Neutron Source, it is shown to be a significant improvement over its current detector, which imposes an instantaneous count rate limitation of 50 kcps.
The report summarizes the environmental significance of the priority pollutants being discharged from thirteen subcategories of the ore mining and dressing point source category. In addition, the impact of proposed effluent limitations guidelines is assessed from an environmental perspective.
The report discusses the capabilities of equipment vendors to supply and install the quantity of flue gas desulfurization systems required to meet alternative standards for coal-fired steam generators. It analyzes limiting factors affecting supply capabilities (such as the availa...
The Calorie (kcal) of present U.S. food labels is similar to the original French definition of 1825. The original published source (now available on the internet) defined the Calorie as the quantity...Full Text Available
The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.
This document is a technical background document for proposed regulations to limit effluent discharges to waters of the United States and introductions of pollutants into publicly owned treatment works from facilities engaged in porcelain enameling. The p...
This paper hopes to share the insights we experienced during designing, building, and running an indexing solution for a large set of radiological reports and images in a production environment for...Full Text Available
Aquaspirillum magnetotacticum MS-1 grew microaerobically but not anaerobically with NO3− or NH4+ as the sole nitrogen source. Nevertheless,...Full Text Available
Drawing on published tobacco document research and related sources, this article applies Farnsworth and Holden's conceptual framework for the analysis of corporate power and corporate involvement...Full Text Available
The influence of location of airborne particle source, ventilation rate, air inlet size, supply air velocity, air outlet location, and heat source on the distributions of airborne particle concentration and draught risk in an operating room is investigated. The investigation is carried out by using a flow program with the k-[epsilon] model of turbulence. Based on a standard case, five cases, each with one changed parameter, are computed, and the detailed field distributions of air velocity, temperature, airborne particle concentration, and draught risk are presented. The parametric study concludes that, for a better air quality and thermal comfort, it is desirable to use a higher inflow rate, a larger inlet area, and a uniform velocity profile of supply air. Outlet location and heat source have little influence on the distributions of the particle concentration in the room. It has also been found that the distributions of ...
I present here a review of past and present multi-disciplinary research of the Pittsburgh Computational AstroStatistics (PiCA) group. This group is dedicated to developing fast and efficient statistical algorithms for analysing huge astronomical data sources. I begin with a short review of multi-resolutional kd-trees which are the building blocks for many of our algorithms. For example, quick range queries and fast n-point correlation functions. I will present new results from the use of Mixture Models (Connolly et al. 2000) in density estimation of multi-color data from the Sloan Digital Sky Survey (SDSS). Specifically, the selection of quasars and the automated identification of X-ray sources. I will also present a brief overview of the False Discovery Rate (FDR) procedure (Miller et al. 2001a) and show how it has been used in the detection of ``Baryon Wiggles'' in the local galaxy power spectrum and source identification ...
Shilajit has been used traditionally in folk medicine for treatment of a variety of disorders, including syndromes involving excessive complement activation. Extracts of Shilajit contain significant...Full Text Available
Massive particle candidates for dark matter provide a potentially observable signature by virtue of their annihilations in the galactic halo at a known but model-dependent rate. Possible signatures are described, including cosmic ray antiproton and gamma-ray production. (orig.).
Klebsiella pneumoniae is able to grow anaerobically with citrate as a sole carbon and energy source by a fermentative pathway involving the Na+-dependent citrate...Full Text Available
This technical report describes an outline, features, total energy efficiency, and specifications of binary heat pump system. A closed circuit distributed water heat source heat pump method is employed in the binary heat pump system. Since the circulating water, which is adjusted at a constant temperature, is used as the heat source of the indoor unit, a stable performance can be obtained regardless of outside atmospheric temperature. The binary heat pump system is mainly composed of a center heat pump unit, indoor heat pump unit, heat source water pipes, and circulating pump. The center heat pump unit and the indoor heat pump unit are connected with each other by the heat source water, and each unit can be operated independently. This system is characterized by the simultaneous operation of cooling and heating, high efficiency, high energy saving, high reliability of system, excellent environmental ...
Atmospheric electrodynamics research is summarized, focusing on three general areas: the ionosphere as a source for middle atmospheric electrodynamics, regional and global scale electrodynamics, and thunderstorms and lightning. New or improved instrumentation techniques which have furthered atmospheric electrodynamics research are also discussed. 93 refs.
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 Δ- and Λ-isomerism of octahedral metal complexes is employed as a source of chirality for inducing chiral nematic phases. By applying a wide range of chiral metal complexes as a...Full Text Available
Anionic peroxidase from tomato (Lycopersicon esculentum) fruit oxidized indoleacetic acid (IAA) slowly in the presence of Mn2+ and dichlorophenol in acetate buffers. The...Full Text Available
The lift and drag characteristics of a wide range of bluff body shapes were studied using data from sources including wind tunnel testing and flow visualization. For a given orientation of any body, it is found that its drag is strongly influenced by its ...
To predict air quality properly at a given location, it is necessary to identify all emission sources that will have significant impact at that location. Furthermore, the atmospheric pollutants that are emitted by these sources must be identified and quantitatively characterized. Once the air-quality predictions have been made, it is desirable to have some historical air-quality data for comparison. An efficient means of obtaining this information is through the use of detailed emission inventories and an inventory of air-quality-monitoring stations. Therefore, as part of the Alberta Government/Industry Acid Deposition Research Program (ADRP), three comprehensive inventories have been developed, namely: a sulfur dioxide (SO/sub 2/) emission inventory, a nitrogen oxides (NOx) emission inventory, and an inventory of air-quality-monitoring stations. Volume 2, Design of the Emission Inventory, presents detailed information on the classification ...
for sensitive personnel data. Based on the judgment of Task Force ...... Gunn, R ., Memorandum on Sub-Atomic Power Sources for Submarine ... Hunley, J., ed., The Birth of NASA: The Diary of T. Keith Glennan, SP-4105, ...
The TRIGA-SPEC experiment has been installed recently at the research reactor TRIGA Mainz. Ground state properties like masses, charge radii, spins, and moments of short-lived nuclides can be determined with very-high precision using the Penning trap mass spectrometer TRIGA-TRAP, and the collinear laser spectroscopy setup TRIGA-LASER. Short-lived neutron-rich radionuclides in the mass range 80 < A < 140 are produced by thermal neutron induced fission of e.g. U-235, Pu-239 or Cf-249, respectively. For the extraction and ionization of the fission products a gas-jet system is coupled to a 2.45-GHz ECR ion source for the production of singly charged ions. The gas-jet has been tested on-line and fission products have been extracted. First off-line tests of the ion source have been performed successfully with argon gas. The results of the commissioning test of the ion source and the on-line coupling of the experiments are ...
Several widely recognized sources of nomenclature regarding the bovine external digit were reviewed, compared, and utilized in a clinical survey of bovine digital disease. During this process, some...Full Text Available
Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra bservations detect the source at a flux of F_X = 2e-12 erg cm^-2 s^-1 (2-8 keV). After accounting for absorption both in the interstellar medium and in material local to the source, the implied luminosity of the source is only L_X = 4e34 erg/s (2-8 keV; D=8 kpc). However, the diffuse X-ray emission near the source also brightened by a factor of 2. The enhanced diffuse X-ray emission lies on top of a known ridge of dust and ionized gas that is visible infrared images. We interpret the X-ray emission as scattered flux from the outburst, and determine that the peak luminosity of CXOGC J174540.0-290031 was ...
Aug 5, 2009 ... and the intelligence community as well. The subsequent process was carried ..... The source of this criticism ranges from concern over technical capability to .... universe with both human and robotic missions, and open ...
ADVANCED MODELING, S IMULATION, AND ANALYSIS (ROADMAP 14). ...... Metal/Silicon Extraction from Regolith & manufacturing ..... addresses solar power, energy storage (in conjunction with solar power and as a prime source of ...
The /sup 252/Cf-source-driven neutron noise analysis method for obtaining the subcriticality of an assembly of fissile material from cross-power spectral densities (CPSDs) was developed to avoid some difficulties inherent in other measurement methods. This method requires measurement of frequency-dependent CPSD between a pair of detectors in or near the fissile assembly and CPSDs between these detectors and a source of correlated neutron noise from an ionization chamber containing /sup 252/Cf, also in or near the fissile assembly. Also, the auto-power spectral density of the source is required. The ratio of spectral densities is then formed and is related to the subcriticality. To date various measurements have been performed which demonstrate the usefulness of the method including measurements with single uranium metal cylinders. The experiments described here, which used coupled uranium (93.15 wt % /sup 235/U) metal ...