DEFF Research Database (Denmark)

Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields and dynamics. Data were analysed using Proper Orthogonal Decomposition (POD). An important periodic event is an elongation of the jet core cross section that results in a downstream displacement of the jet towards the chamber wall.

Energy Technology Data Exchange (ETDEWEB)

Device for separating and collecting ultrafine atomized powder from the gas stream of a gas atomizing apparatus comprises a housing having an interior wall oriented at an angle relative to horizontal so as to form a downwardly converging, conical expansion chamber, an inlet conduit communicated to the expansion chamber proximate an upper region thereof for receiving the gas stream, and an outlet proximate a lower region of the expansion chamber. The inlet conduit is oriented at a compound inclined angle (with respect to horizontal) selected to promote separation and collection of powder from the gas stream in the expansion chamber. The compound angle comprises a first entrance angle that is greater than the angle of repose of the powder on the housing interior wall such that any powder accumulation in the inlet conduit tends to flow down the ...

Energy Technology Data Exchange (ETDEWEB)

As a part of a phenomenological model, a method for simulating the wall/jet interaction in a direct injection diesel engine is proposed. The method is based on the application of the momentum conservation equation in the different directions in which the wall jet is spread, and takes into account both the interaction with the combustion chamber geometry and with swirl. It takes as initial conditions the results of calculating the free jet, which is divided into packages. The predictions provide good agreement with those by other researchers. (author).

Energy Technology Data Exchange (ETDEWEB)

A pump down model for a vacuum chamber with a reversibly adsorbed phase is presented. The outgassing equation which predicts the variation of coverage at the wall surface of a vacuum chamber with time is derived. Then the measured and the true outgassing rates are defined. The theoretical measured outgassing rate shows only a very weak dependence for pumping speed. This prediction is opposite to the experimental result that the measured outgassing rate depends significantly on pumping speed. It is discussed that the experimental measured outgassing rate must be described as the product of the effective pumping speed and the measured pressure in the pumped chamber, in which the measured pressure is equivalent to the equilibrium pressure of the wall surface described by the equilibrium adsorption isotherm as a function of the shifted surface coverage {theta}-{delta}{theta} by a small ...

Energy Technology Data Exchange (ETDEWEB)

The unburned HC in a direct-injection diesel engine is a cause of exhaust odor and SOF emission. Reduction of HC by changing the injection nozzle specifications was attempted in previous studies. In this study, some experiments in which the mixture formation was varied by using different hole diameters in a multihole nozzle and spray angles to the combustion chamber wall have been conducted. When the diameter of injection holes, which influences the fuel adhering to on the cylinder head walls and the combustion chamber wall, becomes smaller, the HC emission in the idling condition, HC deviation from cylinder to cylinder and HC increase with long idling time are decreased. The same effects were obtained by decreasing the diameter of all holes and by injecting the spray downward to the combustion chamber. 13 refs., 13 figs., 1 tab.

International Nuclear Information System (INIS)

When exposure-calibrated ionization chambers are used to calibrate megavoltage X-ray and electron beam therapy machines, the calibration factor can be divided into a chamber-dependent and a chamber-independent component. Until recently, only the chamber-independent part, which has been derived theoretically, has been used; the chamber-dependent component has been ignored. Recent experimental and theoretical considerations, however, have indicated that the dependent component must be taken into account and can affect the calibration by as much as 4%. The calibration can change due to (i) the thickness of the chamber wall, (ii) the chamber wall composition, i.e. whether the chamber is constructed of air-equivalent material, or tissue- or water-equivalent material, and (iii) the ...

UK PubMed Central (United Kingdom)

BackgroundClinical studies suggest that local wall shear stress (WSS) patterns modulate the site and the progression of atherosclerotic lesions. Computational fluid dynamics (CFD)...Full Text Available

International Nuclear Information System (INIS)

This paper consists the radiation streaming analysis of Horizontal penetrations in Calandria Vault of 540 MWe PHWR. There are total 19 penetrations, penetrating east and west walls of calandria vault of 540 MWe PHWR. These penetrations are provided to accommodate ion chambers. HFUs and SDS - 2. Penetrations described here are not present in 220 MWe units except for ion chamber penetrations. As these penetrations are in accessible area, a detailed analysis has been carried out to find out the neutron and gamma dose rates around these penetrations when reactor is operating. Analysis has been carried out using computer code DOT-III and MCNP. Predictions by this method compare well with the measurements at ion chamber locations at KGS-1,2. (author)

Energy Technology Data Exchange (ETDEWEB)

We investigated a method of analyzing the hemodynamics of the lung mass by contrast enhanced dynamic computed tomography (dynamic CT) to determine the difference in vascular supply between the pulmonary artery and bronchial artery using an experimental model. Our experimental model consisted of two injectors connected to two tubes, representing the pulmonary artery and bronchial artery, which were further connected to a chamber representing the lung mass. Following infusion of contrast medium into each tube with some delay time, dynamic CT scans were performed to obtain time density curves of the two tubes and the chamber. Using the time-density curve of contrast passage, flow rates from the two tubes into the chamber were calculated by the curve fitting method. Calculated values correlated well with the adopted flow rates of fluid from the injectors (r=0.893) ...

International Nuclear Information System (INIS)

Both horizontally and vertically oriented rotating chambers with granular material held on the inner surface by centrifugal action are examined. Modifications to the condition for controlled quasi-static flow on an incline plane, phi/sub w/ < #alpha# < phi/sub r/, where phi/sub w/ is the wall friction angle, #alpha# is the angle of inclination of the plane, and phi/sub r/ is the drained angle of repose of the material are examined for the case of horizontal and vertical surfaces of revolution. Allowed included half angles for horizontally oriented chambers are likely to be in the range of 30"0 +- 10"0 for ceramic particles and metal surfaces. For vertical orientations the maximum half-angle of the top cone is slightly less than the wall friction angle phi/sub w/ while the lower portion can have a half angle as large as (90"0 - phi/sub w). Percolation of fines through shearing granular solids is ...

International Nuclear Information System (INIS)

This paper introduces the JNM Special Issue on the development of a first wall for the reaction chamber in a laser fusion power plant. In this approach to fusion energy a spherical target is injected into a large chamber and heated to fusion burn by an array of lasers. The target emissions are absorbed by the wall and encapsulating blanket, and the resulting heat converted into electricity. The bulk of the energy deposited in the first wall is in the form of X-rays (1.0-100 keV) and ions (0.1-4 MeV). In order to have a practical power plant, the first wall must be resistant to these emissions and suffer virtually no erosion on each shot. A wall candidate based on tungsten armor bonded to a low activation ferritic steel substrate has been chosen as the initial system to be studied. The choice was based on the vast experience with these ...

International Nuclear Information System (INIS)

The modeling methods used to compute the neutron-induced activation of target and near-target materials in the NIF facility are presented. A detailed space and energy description of the neutron environment in the different materials is provided. A new capability has been developed to treat in a general way the activation of debris produced in an operational regime of yield and no-yield experiments. First calculations are addressed to analyze the activity of the debris into the target chamber. The contribution of the different components to activity, interior dose rates, and waste disposal rating (WDR) is determined. The importance of the activation coming from primary irradiation in the target, and from secondary irradiation in debris deposited onto the first wall is assessed. Finally, waste hazards of the activated debris when removed out of the chamber and stored are analyzed. (authors)

UK PubMed Central (United Kingdom)

BackgroundCotton fiber development undergoes rapid and dynamic changes in a single cell type, from fiber initiation, elongation, primary and secondary wall biosynthesis, to fiber...Full Text Available

Science.gov (United States)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

Energy Technology Data Exchange (ETDEWEB)

Causes of variation of hydrocarbon (HC) concentration in cylinder to cylinder at idling condition in a direct injection diesel engine were studied. The ratio of l/d=6 gives larger HC variation in cylinder to cylinder than the l/d=2, where l means the nozzle hole length and d means the nozzle hole diameter. This is because the condition of l/d=6 can result in the large spray penetration and increase the fuel on the combustion chamber. The spray structure changes between nozzles and also changes between nozzle holes. This is not caused by the shape of nozzle hole but is affected by the pressure change near the inlet of nozzle hole when the needle valve is lifted. The change of spray structure can change the injection volume between nozzle holes. The injection volume is less for a nozzle hole where the curved angle becomes sharp to the nozzle central angle, and is more at the opposite side. When the injection volume of the nozzle hole near the ...

International Nuclear Information System (INIS)

Gyrokinetic particle simulation of edge pedestal formation and plasma rotation dynamics will be presented, and compared with experimental observations. Realistic tokamak edge geometry is used which include separatrix/X-point and material wall from EFIT g-eqdsk data. In order to handle adequately the spatially inhomogeneous electric potential in the scrape-off region, the full-f electron technique is used, in addition to the full-f ions. Monte Carlo neutral particles with wall recycling coefficient will be included self-consistently with the plasma kinetics. Ion-ion Coulomb collisions will be particle, momentum and energy conserving. Energy source for the pedestal and scrape-off plasmas is the heat flow from the core plasma, and the particle source is the ionization of the neutral atoms which are either wall recycled and/or gas puffed. The simulation will be self-consistent with the first principles ...

Energy Technology Data Exchange (ETDEWEB)

Objective: Optimization and testing of a high temperature combustion chamber for burning coal gas and conventional fuels natural gas or fuel oil. Coal gas is not available in such quantity for testing a full scaled combustion chamber. Therefore the design of the combustion chamber is based of experimental results from model tests and numerical solution procedures. Working program: (1) Analytical model for burning coal gas implemented in an existing computational fluid dynamics (CFD) code. (2) Three-dimensional calculations of a full scaled combustion chamber with a CFD code for flows accompanied by combustion and chemical reaction. (3) Improvement of measuring method for determination of flame temperature and concentration. (4) Temperature and concentration profil measuring in a full scaled combustion chamber by operating with natural gas or fuel oil. Results: ...

Energy Technology Data Exchange (ETDEWEB)

The concepts of general flow and thermal boundary conditions are introduced to treat the interaction between indoor and outdoor thermal environments in computational fluid dynamics (CFD) simulations. The results from a multi-zone model are used to supply the general flow boundary conditions. The energy balance equation at wall-air interfaces is used to supply the general thermal boundary conditions. An example calculation in a 13-room building shows that infiltration influences indoor air flow patterns considerably. The air flow in a room ventilated by displacement is measured and simulated. Two surface coatings are considered, i.e. black walls and aluminum walls. Implementation of these two boundary conditions is essential in predicting air flow patterns, air quality, and thermal comfort in a real building. (author)

International Nuclear Information System (INIS)

A homogeneous turbulent mixing of coolant flows with different temperatures at the fuel assembly inlets is an important requirement to minimize hot spots in a fuel assembly of a High Performance Light Water Reactor (HPLWR). Therefore, the mixing chamber between lower core plate, flow adjuster and the mixing chamber within the cluster foot piece diffuser have been investigated using the Computational Fluid Dynamics (CFD)-code Fluent 6.1 and its implemented k-#epsilon# model. The previously presented 3D-CAD-geometry has been simplified using Gambit 2.1.2 and consists of various inlet and outlet tubes or channels in the foot piece bottom plate, the lower core plate and the flow adjuster establishing the boundaries of two consecutive mixing chambers. The temperature distribution at the inlet of the sub-channels of the cluster fuel assemblies is presented. It reveals temperature variations at the coolant ...

Energy Technology Data Exchange (ETDEWEB)

Dynamic response of pipelines buried in a back-filled rectangular trench in a semi-infinite medium has been investigated. The pipelines are modeled as long cylindrical shells of small thickness. By using the boundary integral representation and finite element method, we have studied the three-dimensional response to account for either pane P or SV wave incident at an arbitrary angle to the pipe-axis. In this paper numerical results are presented for the normal displacements, displacements along pipe-axis, and the hoop stresses in the pipe wall. It is shown that the response depends critically on the back-filled material as well as on the directions of propagation of the incident waves.

Science.gov (United States)

Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study has exploited high-resolution scanning electron microscopy (HRSEM) to reveal the 3-dimensional morphology of PD in the cell walls of algae, ferns and higher plants. Varied patterns of PD were observed in the walls, ranging from uniformly distributed individual PD to discrete clusters. Occasionally the thick walls of the giant alga Chara were fractured, revealing the surface morphology of PD within. External structures such as ...

International Nuclear Information System (INIS)

A comprehensive assessment on the eligibility of reduced activation (RA) steels as structural chamber material in Inertial Fusion Energy thick-liquid concepts is performed. As far as alloying elements, it is shown that the activation of tungsten is a question to discuss. Regarding impurity elements, it is analyzed if they could question the possibility of obtaining real RA steels for shallow land burial (SLB). The effect of the thickness of the liquid wall on the SLB response of alloying and impurity elements is computed. It seems that a reasonable liquid thickness of about 80 cm is allowable to obtain SLB acceptability of real RA steels. And above all, we have estimated the impact of cross section uncertainties when addressing the former questions, and we identify those to be improved. The necessary improvement of some tungsten and niobium cross sections is justified. (authors)

National Aeronautics and Space Administration (NASA)

GPM moves from the clean room to the test chamber on a dolly without wheels. Compressed air is pumped out under airpads that float the Spacecraft on a bed of air. nThe wind generated when the centrifuge moves at its maximum speed are more than 200 mph - that's tornado speed. But since they move with the centrifuge the satellites tested only feel 20 mph winds. nLeaning outward at 45 degrees for one test orientation, GPM comes within 28 inches of the wall. When lifted onto the platform it cleared the ceiling by only five inches. nNatural audio only. nVideo Credit: Brooke Harris n

Energy Technology Data Exchange (ETDEWEB)

Numerical studies are performed to identify an optimal range of geometric parameters in connection with the design of an impingement-conditioned small direct-injection diesel engine. The parametric studies were made in a pressure chamber with a circular protrusion on to which sprays are directed to impinge. Computational runs were made for 24 cases carefully chosen to allow examination of the effects on post-impingement spray characteristics of the following parameters: (a) the nozzle-plate distance and (b) the size and geometry pattern of the protrusion. An optimal range of these parameters has been identified through an analysis of the calculated results in terms of vapour concentration, the Sauter mean diameter of the wall spray and the dispersed wall spray volume. The results obtained also reveals that, by just changing the size of the impingement surface and the impingement distance, local fuel vaporization efficiency ...

International Nuclear Information System (INIS)

Complete text of publication follows. In order to extend the capabilities of the electron cyclotron resonance (ECR) ion source (ECRIS) of ATOMKI it has been transformed into a special plasma facility [1,2]. The transformation is reversible and was simply done by changing several main components of the ion source by new ones, namely: the hexapole magnet, the plasma chamber and the microwave source. The basic requirements of the transformation were: (1) most parts of the present ECRIS should be used in the new assembly in the same way and (2) the transformation time between the two operation modes should not be more than 2-3 days (in both directions). The following sub-systems are used identically in both configurations: solenoid coils, vacuum system, gas dosing system, ovens, probes. The extraction optics and beam transport system can also be used in the new configuration to check the components and charge-state of the plasma. A new, large, but unusually thin ...

Energy Technology Data Exchange (ETDEWEB)

X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and ...

Energy Technology Data Exchange (ETDEWEB)

Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM.

Energy Technology Data Exchange (ETDEWEB)

Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet impingement shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. These leak rates depend on the crack-opening area of a through-wall crack in the pipe. In addition to LBB analyses, which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section 11. This study was requested by the NRC to review, evaluate, and refine current analytical models for crack-opening-area analyses of pipes with circumferential ...

CERN Document Server

Two-dimensional simulations of the coarsening process of the isotropic/smectic-A phase transition are presented using a high-order Landau-de Gennes type free energy model. Defect annihilation laws for smectic disclinations, elementary dislocations, and total dislocation content are determined. The computed evolution of the orientational correlation length and disclination density is found to be in agreement with previous experimental observations showing that disclination interactions dominate the coarsening process. The mechanism of smectic disclination movement, limited by the absorption and emission of elementary dislocations, is found to be facilitated by curvature walls connecting interacting disclinations. At intermediate times in the coarsening process, split-core dislocation formation and interactions displaying an effective disclination quadrupole configuration are observed. This work provides the framework for further understanding of the formation and ...

International Nuclear Information System (INIS)

The aim of this paper is to investigate the fluid dynamic behaviour of a commercial hydraulic proportional valve in order to evaluate and justify its global performances and, in particular, to analyze the effects of some additional design features on the reduction of the force required to maintain the valve open. The proposed analysis has been performed by applying the commercial computational fluid dynamics (CFD) code, Fluent, to the solution of the three dimensional turbulent flow field through a circumferential sector of the entire valve for different spool strokes. The reliability of the employed modelization is demonstrated by the comparison between the computed flow rate curve and the corresponding experimental data provided by the manufacturer. With regard to the metering edge design, it is shown that the cylindrical hole provided on the top of the hemi-spherical notch to improve metering at small valve openings has no influence on the ...

International Nuclear Information System (INIS)

The risk analysis was carried out in consideration of conditions prevailing at the Kalkar site analogous to the investigations in phase A of DRS (German Reactor Study). Earthquake design loads include the probabilities of upper deviations of the site intensities to be expected. The calculations of dynamic loads for select buildings are made using models and computational methods. Component analyses were performed analogous to DRS for the supports of large components, supports of the roof construction of the reactor building taking into account support reserves due to plastic work capacity, wall disks in steam generator buildings and switchboard plant buildings. (DG).

International Nuclear Information System (INIS)

Fe-Cr amorphous films have been formed by both in situ evaporation of multilayered films and ion beam mixing in a target chamber of a 200 keV implanter. The effects of Cr content and ion irradiation on the amorphization of films were examined by transmission electron microscope (TEM). Corrosion of film was investigated by means of a potential dynamic polarization. Corrosion resistance of amorphous film in 0.5 mol H-2SO-4 solution is considerably increased than that of pure iron. Using X ray photoelectron spectroscopy (XPS) corrosion resistance in atmosphere of amorphous Fe-Cr passive films formed by P"+ mixing was studied. Results show that the richness of Cr and P exist at the surface of Fe-Cr film.

Energy Technology Data Exchange (ETDEWEB)

A multi-faceted research program has been performed to investigate in detail several aspects of free and forced convective cooling of underground electric cable systems. There were two main areas of investigation. The first one, reported in Volume 1, dealt with the fluid dynamic and thermal aspects of various components of the cable system. In particular, friction factors for laminar flow in the cable pipes with various configurations were determined using a finite element technique; the temperature distributions and heat transfer in splices were examined using a combined analytical numerical technique; the pressure drop and heat transfer characteristics of cable pipes in the transitional and turbulent flow regime were determined experimentally in a model study; and full-scale model experimental work was carried out to determine the fluid dynamic and thermal characteristics of entrance and exit chambers for the cooling oil. ...

Energy Technology Data Exchange (ETDEWEB)

Interest in finding out passive ways to keep the variation in the indoor climate within the comfort zone is gaining in popularity. One possible solution is the use of the moisture-buffering property of materials. In this study, the effects of the ventilation system and moisture-buffering properties of the building fabric on the stability of the indoor temperature and humidity are analysed by means of long-term field measurements. Indoor climate measurements were carried out in 170 detached houses (248 rooms). Temperature and relative humidity were measured continuously in bedrooms and living rooms at one-hour intervals over a one-year period. In general, it may be concluded that in this study, the ventilation had a greater effect on the indoor climate than the properties of the building fabric. The dampening effect of hygroscopic materials was remarkably less in the field measurements than it was in simulations in different studies. This indicates that completely non-hygroscopic and ...

Energy Technology Data Exchange (ETDEWEB)

A joint US/Russia program is being conducted to develop, fabricate, launch, and operate a solar dynamic demonstration system on Space Station Mir. The goal of the program is to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station Alpha. The major components of the system include a heat receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a concentrator, a radiator, a thermal control system, and a Space Shuttle carrier. This paper discusses the design of the heat receiver component. The receiver comprises a cylindrical cavity, the walls of which are lined with a series of tubes running the length of the cavity. The engine working fluid, a mixture of xenon and helium, is heated by the concentrated sunlight incident on these tubes. The receiver incorporates integral thermal storage, using a eutectic ...

Energy Technology Data Exchange (ETDEWEB)

Formaldehyde release from building products is primarily due to incompletely reacted urea-formaldehyde resin (UFR) in particleboard, medium density fiberboard (MDF), and plywood. Formaldehyde is also released from urea-formaldehyde foam insulation (UFFI) that was popular during the 1970s for retrofitting building envelopes. Results of the authors test of commercial adhesives and UF-bonded wood products show that current state-of-the-art products yield air chamber test values below 0.25 mg/m/sup 3/ immediately after manufacture and are capable of meeting 0.12 mg/m/sup 3/ indoor air standards at the current product ratio unless these products are used in places where they are exposed to high temperature and humidity. In mobile homes placed in severe climates, wall-temperature profiles show large seasonal and diurnal variations that cause large changes in formaldehyde indoor air levels. The authors work shows that diurnal formaldehyde levels may ...

Energy Technology Data Exchange (ETDEWEB)

A compact cesium deposition system was used for direct deposition of cesium atoms and ions onto the inner surface of the 1/3 scale Hydrogen Negative Ion Source for the LHD-NBI system. A small, well defined amount of cesium deposition in the range of 3-200 mg was tested. Negative ion extraction and acceleration were carried out both in the pure hydrogen operation mode and in the cesium mode. Single Cs deposition of 3-30 mg to the plasma chamber have produced temporary 2-5 times increases of H-yield, but the yield was decreased within several discharge pulses to the previous steady-state value. Two consecutive 30 mg depositions done within a 3-5 hours/60 shot interval, produced a similar temporary increase of H-beam, but reached a larger H-yield steady-state value. Deposition of larger 0.1-0.2 g Cs portions with a 20-120 hours/150-270 shot interval improved the H-yield for a long (2-5 days) period of operation. Directed depositions of Cs to the various ...

International Nuclear Information System (INIS)

This paper (paper I) presents the first part of results obtained with the PF-1000 facility for the first time at its upper energy limit (?1 MJ). Special attention is paid here to plasma ('pinch') dynamics, which was investigated in relation to its electro-technical and radiation (especially neutron) characteristics with the help of a number of diagnostics, both time-integrated and with nanosecond temporal resolution. In these methods we utilized a Rogowski coil for the routine electro-technical measurements, visual multi-frame and streak cameras, soft x-ray pin-hole multi-frame cameras, PIN-diode assembly and PM tubes with scintillators for soft and hard x-rays as well as for neutron investigations together with a set of activation counters. In particular, the temporal cross correlation of different phenomena taking place during the discharge was investigated. The pinch's longevity appears to be 10-15 times larger than the ideal magnetohydrodynamic growth time ...

International Nuclear Information System (INIS)

The measurement of two-phase flow parameters for development of constitutive relationships for the HANARO/MAPLE type finned fuel using Real-Time Neutron Radiography (RTNR) is discussed in this paper. A single element finned Fuel Element Simulator (FES) was used with Freon 134a as the working fluid. To observe the effect of a spacer device on void distribution, single pin tests were performed with and without a spacer present. By analyzing the RTNR images using image processing, the effects of the spacer on the time-averaged and instantaneous void fraction distribution were studied. For the experimental results without a spacer, the time-averaged local void distribution is radially asymmetric and the degree of void fluctuation increases with a decreasing frequency along the heated channel, where the observed asymmetry may be caused by flow induced vibration. For the experimental results with a spacer, the spacer clearly limits any significant vibration and the local void distribution ...

Energy Technology Data Exchange (ETDEWEB)

When liquids are confined in nano-scopic dimensions, their properties differ from the corresponding bulk liquid, due to their reduced dimensionality and surface effects. Phase transition temperatures and pressures are often shifted from the bulk values and new phases can appear due to the strong interactions of the molecules with the confining walls. We have studied the structural and dynamical properties of aromatic liquids such as benzene, toluene, and ortho-terphenyl confined in nano-porous materials, MCM-41 and SBA-15, synthesized and characterized in our laboratory. A non-trivial dependence of the glass transition temperature, T{sub g}, on the pore size and surface treatment of nano-porous materials is confirmed and interpreted as resulting from a competition between the fluid-wall and fluid-fluid intermolecular interactions. An increase of T{sub g} is observed for small pore sizes and attractive surface while T{sub g} ...

British Library Electronic Table of Contents (United Kingdom)

The adsorption of CO2 on a number of activated carbons, thermal carbon black, and oxide materials at 195 K was studied using static and dynamic techniques. The landing surface areas ?(CO2) ? 0.19 nm2 on thermal carbon black and the absolute values of sorption for P/P 0 < 0.4 were determined. The density of adsorbed CO2 in the micropore volume was estimated at ?(CO2) = 0.91 g/cm3. It was demonstrated that the previously found effect of a weakening of the sorption interaction of nitrogen molecules with thin-walled materials (which manifested itself in an analysis of sorption isotherms by a comparative method) was pronounced to a lesser degree for the sorption of CO2. At the same time, the presence of supermicropores in activated carbon samples resulted in overestimated values of surface area...

International Nuclear Information System (INIS)

About 210 abstracts by Ukrainian and foreign authors submitted to the 11-th International Conference on Plasma Physics and Controlled Fusion and 2-nd Alushta International Workshop on the Role of Electric Fields in Plasma Confinement in Stellarators and Tokamaks have been considered by Conference Program Committee members. All the abstracts have been divided into 9 groups: Magnetic confinement systems (stellarators, tokamaks, alternative conceptions); plasma heating and current drive; ITER and fusion reactor aspects; basic plasma physics; space plasma; plasma dynamics and plasma-wall interaction; plasma electronics; low temperature plasma and plasma technologies; plasma diagnostics.

CERN Document Server

Dynamic system identification

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

... Mohamed, MM Medical Research Institute (Egypt) Ghatass, ZF Institute of

Science.gov (United States)

... TEMPERATURE, PRESSURE MEASUREMENT, GUN CHAMBERS, COMPACTING, COMBUSTIBLE CARTRIDGE CASES, FLASH RADIOGRAPHY ...

International Nuclear Information System (INIS)

A multiwire cylindrical drift chamber is the main detector of the AMPIR 4#pi#-spectrometer for studying pion-nucleon reactions. The chamber has possibility to measure three coordinates by the electron drift time and by the charge division method. Chamber design and geometry, test bench, readout electronics and also results of calculations, simulation and tests are described.

International Nuclear Information System (INIS)

A cylindrical multiwire drift chamber is the central detector of the AMPIR spectrometer. It has 4#pi# acceptance angle and was designed to study pion-nucleon reactions. The chamber can determine the three coordinates through the electron drift time and charge division ration. The paper describes the layout and design of the chamber, the test bench, the data output circuit, the design parameters, and the results of computer simulations and tests.

Energy Technology Data Exchange (ETDEWEB)

Emissions of nitric oxide from soils of equatorial rain forest were measured in the Dimonika Natural Park (4 degrees 30'S, 12 degrees 30'E) in the Mayombe Forest in Congo. Three research campaigns were carried out in June and July 1991 and in February 1992. Fluxes were measured by dynamic chamber techniques using a chemiluminescence instrument Scintrex LMA3. NO fluxes measured on natural soils are in between 5 and 17x10[sup 9] molecules cm[sup -2]s[sup -1]; they are of the same order of magnitude as those observed in similar tropical forest media. Soil treatment experiments show that the auto-decomposition of HNO[sub 2] in these acid soils (pH 4) (chemodenitrification) is a potentially important cause of nitric oxide production in this type of ecosystem. Nitrous acid comes from autotrophic nitrification all the year around, and also from biological denitrification, shown by N[sub 2]O emissions, during the rainy season. The ...

International Nuclear Information System (INIS)

An original dc double anode plasma torch which provides a long-time and highly stable atmospheric plasma jet has been devised for the purpose of hazardous waste treatment. The arc fluctuations and dynamic behaviour of the argon and argon-nitrogen plasma jets under different operating conditions have been investigated by means of classical tools, such as the statistic method, fast Fourier transform (FFT) and correlation analysis. In our experiments, the takeover mode is identified as the fluctuation characteristic of the argon plasma jet while the restrike mode is typical in the argon-nitrogen plasma dynamic behaviour. In the case of pure argon, the FFT and correlation calculation results of electrical signals exhibit the only characteristic frequency of 150 Hz, which originates from the torch power and is independent of any change in the operating conditions. It indicates that the nature of fluctuations in an argon plasma jet is mainly induced ...

Energy Technology Data Exchange (ETDEWEB)

A custom-built graphite-coated transmission ionization chamber is compared to the VacuDAP 2001 (VacuTec, Dresden, Germany), which has transparent conductive electrodes. A study was made of the dependence of response on x-ray tube potential for both types of chamber under identical conditions of exposure using over-table and under-table x-ray tubes. Since the calibration factor is the dose-area product of the radiation incident on the patient per chamber reading, it depends on the intrinsic response of the chamber as well as the effect of material in the beam between the x-ray tube and patient. Differences of about 20% were measured between the intrinsic and the over-table calibration factors and between the over-table and the under-table calibration factors for both chambers. The VacuDAP display is specifically calibrated for the over-table condition and would overstate the actual ...

Energy Technology Data Exchange (ETDEWEB)

The IPIRG-2 program was an international group program managed by the US NRC and funded by organizations from 15 nations. The emphasis of the IPIRG-2 program was the development of data to verify fracture analyses for cracked pipes and fittings subjected to dynamic/cyclic load histories typical of seismic events. The scope included: (1) the study of more complex dynamic/cyclic load histories, i.e., multi-frequency, variable amplitude, simulated seismic excitations, than those considered in the IPIRG-1 program, (2) crack sizes more typical of those considered in Leak-Before-Break (LBB) and in-service flaw evaluations, (3) through-wall-cracked pipe experiments which can be used to validate LBB-type fracture analyses, (4) cracks in and around pipe fittings, such as elbows, and (5) laboratory specimen and separate effect pipe experiments to provide better insight into the effects of dynamic and cyclic load ...

Energy Technology Data Exchange (ETDEWEB)

A numeric method for predicting mineral ash deposition in coal dust furnaces is presented which is based on a bidirectional working time coupling of thermodynamic calculation routines (ChemApp{sup TM}) with the commercial CFD code FLUENT{sup TM}. The deposition characteristics of particles and wall surfaces is assessed on the basis of evaluations of flow simulation parameters and results of thermodynamic calculations for the mineral matter contained in the fuel particles, taking into account the complete energy, momentum and mass exchange history of the ash and the mineral conversion. The models enables calculations of the gaseous release of mineral components (e.g. alkaline substances and chlorine) from ash during combustion and its distribution inside a combustion chamber. The method and model are validated using experimental data. (orig.) [German] In der vorliegenden Arbeit wird ein numerisches Verfahren beschrieben, mit dem die ...

Wastenet

... Radon gas concentrations are measured using instruments with calibrations traceable to the UK National Physical Laboratory and PTB, Germany. The primary facility is a 43 m3 walk-in chamber accessed by an airlock. Radon gas is maintained at a level in this chamber that is ...

UK PubMed Central (United Kingdom)

Purpose:To investigate the clinical usage of dose verification of Helical Tomotherapy plans by using 2D-array ion chambers, and to develop an efficient way to validate the dose delivered...Full Text Available

International Nuclear Information System (INIS)

The goal of this work is to present a systematic Monte Carlo validation study on the clinical implementation of the enhanced dynamic wedges (EDWs) into the Pinnacle"3 (Philips Medical Systems, Fitchburg, WI) treatment planning system (TPS) and QA procedures for patient plan verification treated with EDWs. Modeling of EDW beams in the Pinnacle"3 TPS, which employs a collapsed-cone convolution superposition (CCCS) dose model, was based on a combination of measured open-beam data and the 'Golden Segmented Treatment Table' (GSTT) provided by Varian for each photon beam energy. To validate EDW models, dose profiles of 6 and 10 MV photon beams from a Clinac 2100 C/D were measured in virtual water at depths from near-surface to 30 cm for a wide range of field sizes and wedge angles using the Profiler 2 (Sun Nuclear Corporation, Melbourne, FL) diode array system. The EDW output factors (EDWOFs) for square fields from 4 to 20 cm wide were measured in virtual water using a ...

International Nuclear Information System (INIS)

(Dec 1977). United Kingdom Paliwal, BR Wochos, JF Wisconsin Univ., Madison

CERN Document Server

The conceptual design of the support structures of the EM muon chambers is presented. On each side of the detector the EM chambers are arranged in four layers: one layer of MDTs and the three layers of TGCs. The chambers are mounted on four individual wheel structures per side. The four wheels are inclined by 1.23% and suspended from two longitudinal beams parallel to the beam axis. In order to allow for the opening of the ATLAS detector the wheels can be displaced longitudinally over a distance of 6 m. In addition individual wheels can be separated from each other by up to 1 m for maintenance purposes.

Science.gov (United States)

... Descriptors : *Combustible cartridge cases, *Polymers, *Test equipment, *Patents, Combustion chambers, Breech mechanisms, Gas generating ...

UK PubMed Central (United Kingdom)

Terminal differentiation of many vascular cells involves cell wall changes. Cells first elongate their primary wall, then lay down a lignified secondary wall, which is often followed by digestion of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The neutron detector is cased in a metal envelop and has one detector with a very sensitive fission chamber and a second detector with a fission chamber less sensitive that the first one and a boron coated ionisation chamber for reducing gamma radiation detection.

Energy Technology Data Exchange (ETDEWEB)

Since the most efficient way to improve fuel economy in the part-load range is to increase the compression ratio, emphasis is placed on combustion chambers allowing high compression ratios combined with low octane requirements. According to Porsche experience, many demands can be met in the simplest manner by locating the combustion chamber in the piston crown. This configuration offers various advantages over its counterpart installed in the cylinder head. 24 refs.

International Nuclear Information System (INIS)

A new method named 'Bragg curve spectroscopy', based on the Bragg curve of the heavy ion being stopped in a gaseous ionization chamber, has been developed for identifying the particle and measuring its energy. The design of such a chamber and the experience obtained with chamber using various kinds of fast heavy ions are described. In conclusion, several problems to be solved in this method are pointed out. (orig.).

International Nuclear Information System (INIS)

We consider spatially homogeneous (but generally non-isotropic) cosmologies in the recently proposed Horava-Lifshitz gravity and compare them to those of general relativity using Hamiltonian methods. In all cases, the problem is described by an effective point particle moving in a potential well with exponentially steep walls. Focusing on the closed-space cosmological model (Bianchi type IX), the mixmaster dynamics is now completely dominated by the quadratic Cotton tensor potential term for a very small volume of the universe. Unlike general relativity, where the evolution toward the initial singularity always exhibits chaotic behavior with alternating Kasner epochs, the anisotropic universe in Horava-Lifshitz gravity (with parameter #lambda# > 1/3) is described by a particle moving in a frozen potential well with fixed (but arbitrary) energy E. Alternating Kasner epochs still provide a good description of the early universe for very large ...

Energy Technology Data Exchange (ETDEWEB)

Both x-ray and optical cone-beam CT (CBCT) scanners are limited by scattered photons that contaminate the primary images. Transparent radiochromic gels and plastics are anticipated to produce less scattering than polymerization gels and hence result in reconstructed dose distributions with greater contrast and dynamic range. Four methods of scatter measurement were investigated to quantify scatter fractions using an in-house optical CBCT scanner. The methods consisted of generating either 'coin' shadows or primary beamlets in transmission images. The four methods generated similar results of 10% scatter fractions in gel transmission images for this particular scanner configuration with both leuco crystal violet and carbon black micelle gels. The scatter contributions were distributed as 5% from micelle gel, 2% from Teflon wall, 2% from refractive index matching liquid and 1% other sources. Applying a uniform background ...

Energy Technology Data Exchange (ETDEWEB)

This work presents comparative results of a numerical investigation of four possible models for the prediction of thermal performance of fixed bed storage units and their thermal design. These models includes Schumann's model, the radial dispersion model, a model that include both axial heat conduction in the fluid phase and admits thermal gradient in the solids particles and finally a two dimensional single phase model. For each of these models a computer code was written and tested to evaluate the computing time of same data and analyze any other computational problems. The tests of thermal performance included particle size, porosity, particle material, flow rate, inlet temperature and heat losses form tank walls and extremities. Dynamics behaviour of the storage units due to transient variation in either flow rate or inlet temperature was also investigated. The results presented include temperature gradients, pressure drop and heat ...

Energy Technology Data Exchange (ETDEWEB)

The Computational Fluid Dynamics(CFD) study was conducted to assess the new design concept introduced to solve the issues on the flow deviation between SG cassettes and the supporting structure design of the flow distributing plate subjected to the flow induced vibration. Flow field from MCP to the bottom of SG was modeled for 2-dimensional(2D) CFD analysis and then sensitivity analysis on major design parameters was conducted using commercial CFD code, Fluent. The cases for detailed 3D analysis were selected based on the result of 2D analysis and the detailed 3-dimensional(3D) analysis was conducted for these selected cases using Fluent code. Flow field was modeled by RNG model and wall function, 2nd upwind scheme, porous model, structured or hybrid grid. The analysis result shows that the maximum deviation of flow distribution between SG cassettes was reduced upto about 0.1% and the pressure loss from the SG header to SG orifice was also ...

International Nuclear Information System (INIS)

The evaluate the signs of aortic intramural hematoma with helical CT and the diagnostic role of this technique in patients with this condition. It was reviewed the CT findings of 396 patients submitted to emergency examinations for suspected aortic dissection from 1995 to 1999. Only 18 patients (6 women and 12 men) had CT signs of aortic intramural hematoma. Helical CT studies were carried out with the following parameters: slice thickness 10 mm, reconstruction index 10, feed 1.5 mm, conventional algorithm with minimum values of 130 kV and 125mA. All patients were examined with dynamic contrast-enhanced CT, before and after a power injection of 130 mL ionic contrast material. It was studied: hematoma localization and longitudinal extension; thickness and density of aortic wall; presence and location of intimal calcifications; integrity of intimal wall; hemo mediastinum and/or hemo thorax. Aortic wall ...

International Nuclear Information System (INIS)

Real-time neutron radiography has been used to study the dynamic behavior of two-phase flow and measure the time averaged vapor fraction in a heated metal tube containing boiling steam-water operating at up to 15 bar pressure. The neutron radiographic technique is non-intrusive and requires no special transparent window region. This is the first time this technique has been used in an electrically heated pressurized flow loop. This unique experimental method offers the opportunity to observe and record on videotape, flow patterns and transient behavior of two-phase flow inside opaque containers without disturbing the environment. In this study the test sections consisted of stainless steel tubes with a 1.27 cm outer diameter and wall thicknesses of 0.084 and 0.124 cm. The experiments were carried out at the Pennsylvania State University 1 MW TRIGA reactor facility utilizing a Precise Optics neutron radiography camera. The inlet water ...

Energy Technology Data Exchange (ETDEWEB)

The buoyancy driven convective flow fields are steady circulatory flows which were made between surfaces maintained at two fixed temperatures. They are ubiquitous in nature and play an important role in many engineering applications. Application of a natural convection can reduce the costs and efforts remarkably. This paper focuses on the sensitivity study of turbulence analysis using CFD (Computational Fluid Dynamics) for a natural convection in a closed rectangular cavity. Using commercial CFD code, FLUENT and various turbulent models were applied to the turbulent flow. Results from each CFD model will be compared each other in the viewpoints of grid resolution and flow characteristics. It has been showed that: -) obtaining general flow characteristics is possible with relatively coarse grid; -) there is no significant difference between results from finer grid resolutions than grid with y{sup +} < 0.35, where y{sup +} is defined as y{sup +} = ...

CERN Document Server

We study the production of gravitational waves from cosmic domain walls created during phase transition in the early universe. We investigate the process of formation and evolution of domain walls by running three dimensional lattice simulations. If we introduce an approximate discrete symmetry, walls become metastable and finally disappear. We calculate the spectrum of gravitational waves produced by collapsing metastable domain walls. Extrapolating the numerical results, we find the signal of gravitational waves produced by domain walls whose energy scale is around 10^10-10^12GeV will be observable in the next generation gravitational wave interferometers.

International Nuclear Information System (INIS)

The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the CDF II central outer tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers and are associated to electromagnetic clusters and muon stubs to generate trigger electron and muon candidates. The steady increase of the Tevatron instantaneous luminosity and the resulting higher occupancy of the chamber demanded an upgrade of the original system, which performed tracking only in the transverse plane of the chamber and was consequently affected by a significant level of fake tracks. In the upgraded XFT, tracking is reinforced by using additional data from the stereo layers of the chamber to reduce the level of fake tracks and to perform three-dimensional track reconstruction. A review of this upgrade is presented.

International Nuclear Information System (INIS)

An ionization chamber with fast timing properties was built at CERN for measuring fission cross-sections of minor actinides at the n(_)TOF neutron beam. The design of this new chamber and of the front-end electronics was optimized to match the innovative features of the n(_)TOF facility, in particular the high instantaneous neutron flux and low background. For the most radioactive isotopes, a special version of the chamber, designed according to the ISO2919 standards, was built in order to comply with the radioprotection requirements at CERN. The detector and front-end electronics are here described, together with the simulated and measured response to fission fragments and #alpha#-particles. The performances of the chamber during the first measurement campaign at n(_)TOF are presented, focusing in particular on the fast time response, the good background rejection capability, low-background and high ...

Energy Technology Data Exchange (ETDEWEB)

Operation safety and reliability are major guidelines in the design of city-gate units. Conventional natural gas heaters operate by a indirect mechanism, where liquid water is used to transfer heat by natural convection between the combustion chamber and the natural gas coil. In this work, the concept of vapor chamber is evaluated as an indirect gas heater. In a vapor chamber, liquid water is in contact with the heat source, and vaporizes. The vapor condenses in contact with the heat sink. A reduced scale model was built and tested in order to compare these two heating concepts where the combustion chamber was replaced by electrical cartridge heaters. This engineering model can operate either as a conventional heater or as a vapor chamber. The comparison between the concepts was done by inducing a controlled power to the cartridges and by measuring the resulting temperature ...

Energy Technology Data Exchange (ETDEWEB)

Real-time neutron radiography is being evaluated for studying the dynamic behavior of two-phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. An air-water flow system was constructed to simulate vapor conditions encountered in a fluid flow duct. Air was injected into the bottom of the duct at flow rates up to 0.47 {ell}/s (1 ft{sup 3}/min). The water flow rate was varied between 0 and 3.78 {ell}/min (0 to 1 gal/min). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10{sup 6} n/cm{sup 2}{center_dot}s{sup {minus}1} directed through the thin duct dimension, the dynamic behavior of the air bubbles was clearly visible through 5-cm (2-in.)-thick aluminum support plates placed on ...

International Nuclear Information System (INIS)

Real-time neutron radiography is being evaluated for studying the dynamic behavior of two-phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. An air-water flow system was constructed to simulate vapor conditions encountered in a fluid flow duct. Air was injected into the bottom of the duct at flow rates up to 0.47 ell/s (1 ft"3/min). The water flow rate was varied between 0 and 3.78 ell/min (0 to 1 gal/min). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10"6 n/cm"2#centre dot#s"-"1 directed through the thin duct dimension, the dynamic behavior of the air bubbles was clearly visible through 5-cm (2-in.)-thick aluminum support plates placed on both sides of the duct ...

International Nuclear Information System (INIS)

The COSA II (computer codes for salt) benchmark problem has been pursued with the ADINA (Automatic Dynamic Incremental Nonlinear Analysis) program code. With the use of this, the code should be validated by means of experimental data and the ability to reproduce real-life calculation results of the KfK (Kernforschungszentrum Karlsruhe/Nuclear Research Center in Karlsruhe) should be proven. A successful validation of the code then forms the foundation stone for the ability to use different calculation problems in the final (ultimate) storage. This also accompanies the consequent reaction of replacing the STEALTH (Solids and Thermal Hydraulics Code for EPRI Adapted from LAGRANGE TOODY and HEMP) program which has a number of program-specific weaknesses compared to the ADINA computer code. In order to reproduce the approximate values from the KfK, the same values have been used. Differences were evident in the discretion and the selection of the initial values for ...

Energy Technology Data Exchange (ETDEWEB)

As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBRS) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. Solids motion is also ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In a reactor environment, the surface of a limiter or wall is primarily determined by the mechanism of erosion and deposition of surface material. It should be possible to use pellet injection to reduce net erosion to zero everywhere if low-Z materials are used for the surface. Erosion rates can, in general, be minimized by large area limiters and high plasma temperatures, which transmit power to the walls with less sputtering. Under ideal steady state conditions the wall surface is dominated by metallurgical effects in the wall.

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Here we report a new method for measuring the heterogeneous chemistry of submicron organic aerosol particles using a continuous flow stirred tank reactor. This approach is designed to quantify the real time heterogeneous kinetics, using a relative rate method, under conditions of low oxidant concentration and long reaction times that more closely mimic the real atmosphere. A general analytical expression, which couples the aerosol chemistry with the flow dynamics in the chamber is developed and applied to the heterogeneous oxidation of squalane particles by hydroxyl radicals (OH) in the presence of O2. The particle phase reaction is monitored via photoionization aerosol mass spectrometry and yields a reactive uptake coefficient of 0.51+-0.10, using OH concentrations of 1-7x108 molec cdot cm-3 and reaction times of 1.5+-3 hours. This uptake coefficient is larger than that found for the reaction carried out under high OH concentrations (~;;1x1010 ...

International Nuclear Information System (INIS)

A microwave hydrogen ion source was developed to improve reliability, and to increase operation time of proton linac application systems. The ion source needs no filament in the discharge chamber, which leads to better reliability and less maintenance time. The developed source produced a maximum hydrogen ion beam current of 70 mA (high current density of 360 mA/cm2, beam energy of 30 keV) with a 5 mm diam extraction aperture and 1.2 kW microwave power. The proton fraction was increased with an increase in rf power and reached around 90% at 1 kW. Measured 90% beam normalized emittance was 0.4 #pi# mm mrad. Rise times of rf power and beam current to 90% of the final values were about 30 and 35 #mu#s, respectively, at a pulse operation mode with 400 #mu#s pulse width and 100 Hz repetition rate. The dynamic range of beam currents was enlarged (3-63 mA) in the pulse mode with a modified rf wave form to assist ignition of microwave discharge. These ...

Energy Technology Data Exchange (ETDEWEB)

Radiological findings of chest and abdominal wall involvement in Hodgkin's disease are reported. This manifestation was diagnosed in one patient in the primary staging and in two patients during the course of the disease. Typical radiological findings are soft tissue masses in the chest and abdominal wall, in two cases with continous tumor growth of enlarged mediastinal lymphnodes into the anterior chest wall. The axial computed tomography is the best method to evaluate the extent of chest and abdominal wall involvement in Hodgkin's disease.

Energy Technology Data Exchange (ETDEWEB)

Simultaneous reduction of NO{sub x} and particulate emissions in a direct-injection diesel engine has been realized experimentally with a high squish combustion chamber. The purpose of this study is to investigate the effects of high squish combustion chamber on combustion process in detail. Engine CFD code FREC was used for the analysis. The results show the followings. (1) Compared with standard toroidal chamber, high squish chamber generates high turbulence due to strong squish and large expansion flow is caused in the cavity. (2) Rich and high-turbulence combustion, which forms ring area in the cavity under squish lip, continues during the combustion. (3) The high squish combustion chamber keeps fuel long in the cavity and less hid spreads out to the cold clearance volume. (4) For the condition of retarded injection timing, the effect of high squish is mainly observed at initial ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the experimental results of accelerated aging tests conducted on three different types of polymer materials. Salt fog chamber tests were used to study the surface degradation modes for all materials. The work presented here was performed using a newly constructed fog chamber system that was able to control both chamber humidity and UV radiation. The changes in the surface morphology, material structure and leakage current were examined to study the influence of environmental humidity.

Energy Technology Data Exchange (ETDEWEB)

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 mid 1980s (Ref. [2]; see also a survey [3] with discussion of ...

Energy Technology Data Exchange (ETDEWEB)

In order to realize simultaneous reduction of NO{sub x} and Particulate emissions, effects of combustion chamber geometry were investigated in a high speed direct-injection diesel engine. The reentrant combustion chambers with different throat diameter were compared in terms of engine performance, combustion characteristics and emissions such as NO{sub x}, particulate and THC. The phenomena of combustion process were also observed with endoscopic high speed photography. The results showed that when the throat diameter of a reentrant combustion chamber was reduced to an extent, NO{sub x} and particulate decreased simultaneously due to retarded injection timing and the intensified squish. (author)

Science.gov (United States)

Some non-human animals may possess the ability to recall the "what", "where", and "when" of a single past event. We tested the hypothesis that male meadow voles possess the capacity to recall the "what", "where", and "when" of a single past event associated with mate selection in two experiments. Briefly, male voles were allowed to explore an apparatus that contained two chambers. One chamber contained a day-20 pregnant female (24 h prepartum). The other chamber contained a sexually mature female that was neither pregnant nor lactating (REF female). Twenty-four hour after the exposure, the males were placed in the same apparatus, which was empty and clean. At this time, the pregnant female would have entered postpartum estrus (PPE), a period of heightened sexual receptivity. Males initially chose and spent significantly more time investigating the chamber that originally housed the pregnant female (now ...

Energy Technology Data Exchange (ETDEWEB)

A design is proposed for forming the rear screen of a chamber firebox at the point of aerodynamic projection and a design for attaching the pipes of the aerodynamic projection using girders linked with the screen by hinges and movable connections.

International Nuclear Information System (INIS)

A review of tests on earthquake-resistant reinforced concrete structural walls is presented. Laboratory tests of isolated walls and construction joints are discussed. Where appropriate, design recommendations are given. The review indicates only few experimental data are available for short walls which are directly applicable to nuclear power plant design. In particular, tests of short rectangular walls subjected to load reversals are needed. Tests are also needed to determine the damping and frequency characteristics of cracked short walls. Analytical and experimental results should be correlated so that the hysteretic response observed in tests can be realistically related to the analytical response 'demand' of nuclear power plant structures. (Auth.).

International Nuclear Information System (INIS)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The dwelling is equipped with solar collectors which heat the air circulating in the cavity walls and the space beneath the floors. The thermal aspects of such a building are described. Heat balance, losses, heating by the sun in different seasons are described. Different measures taken to reduce the energy losses are described.

International Nuclear Information System (INIS)

This report describes a field-test program to determine the effectiveness of a polymeric wall sealant to reduce the escape of naturally occurring radioactive gas radon from the walls of an underground uranium mine into the ventilation air.

UK PubMed Central (United Kingdom)

Poland's anomaly is an uncommon congenital aberration of the chest wall characterized by absence of the pectoralis major muscle and other nearby musculoskeletal components. In this series, a wide spectrum...Full Text Available

UK PubMed Central (United Kingdom)

Blunt chest-wall trauma is common; however, resultant tricuspid valve rupture is rare and can be subtle in its presentation. Transthoracic echocardiography plays a key role in diagnosis.Herein,...Full Text Available

UK PubMed Central (United Kingdom)

Primary cell walls, free from cytoplasmic contamination were prepared from corn (Zea mays L.) roots and potato (Solanum tuberosum) tubers. After EDTA treatment, the...Full Text Available

UK PubMed Central (United Kingdom)

Purified cell walls were prepared from roots of Horse bean (Vicia faba L., var. minor) and Yellow Lupine (Lupinus luteus L.). Two methods were used:...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Three types of drift chambers are being constructed for the Fermilab D/O/ experiment. The construction and readout of these chambers stress good spatial resolution, good two hit separation, and dE/dx. A 106 MHz FADC system with hardware zero suppression is being constructed to readout this system. 8 refs., 12 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

This is a patent for a device to increase compaction of the loaded batch in a coking chamber that assures a balanced compaction of the batch from the upper to the bottom layer. The leveling rod has a device on the external end that causes the rod to shift vertically and bring pressure on the material and the pressing attachment. Opposite the loading hoppers of the coking chambers there are guides that ensure the rod will be sunk perpendicularly into the loaded material.

Energy Technology Data Exchange (ETDEWEB)

A combined gas/steam turbine process includes a high-pressure furnace and a high pressure gasification unit with a mounted upstream of a combustion chamber there is a gas turbine with a waste heat system. Combustion heat which is not needed to heat the flue gas to combustion temperature is released from the furnace and transferred to ths combustion air going into the combustion chamber.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

A new type of ionization chamber with levitated electrode has been developed. In this ionization chamber, an ion-collection electrode levitates in the air without getting any physical support from the insulator. The electrode is charged by an electrostatic charger without physical contact. The charge of the electrode is read out at a Faraday cage periodically at a given time interval without physical contact. Because its electrode levitates, the ionization chamber produces no background current caused by leaks or piezo current. In addition, as the charging of its electrode and the read-out of its charge are carried out without physical contact, no irregular charge or contact potential difference due to the chattering between electrode and contact point occurs. Through experiments, it was found that this ionization chamber was able to measure the {gamma}-ray dose such as the environmental radiation with ...

Energy Technology Data Exchange (ETDEWEB)

Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

Energy Technology Data Exchange (ETDEWEB)

A quantitative description is proposed for the depletion-induced slip thickness and velocity profile of a polymer solution near the wall-fluid interface in simple shear flow. The inhomogeneous polymer density profile at a flat wall is inserted into the equations of motion for the flow of a polymer solution near the flat wall. The theory is in quantitative agreement with simulation results. (letter to the editor)

International Nuclear Information System (INIS)

Statements about the dynamic processes of uptake, transport, and deposition of Ca and Mg in norway spruce and Scots pine are made in this paper. Concerning the storage of these elements it is shown that there are great differences in their functional importance in cell metabolism. There is evidence that the role of Mg in enzyme and protein metabolism is of far greater significance for the understanding of Mg-deficiency symptoms than its function as the central atom of the chlorophyll complexes. In regard to the transport and especially to the incorporation of Ca into the needles differences between species were evident, expressing the special status of pine among the gymnosperms. With increasing needle age an accumulation of Ca-oxalate crystals, which are physiologically inert, could be proved for the studied conifers. This was interpreted as a 'detoxication' from surplus Ca to hold constant the level of the physiologically active fraction. Accordingly, the low ...

Energy Technology Data Exchange (ETDEWEB)

Nonlinear two-dimensional theory of the space charge of an axially symmetric electron beam propagating in combined right-hand polarized wiggler and uniform axial guide fields in a presence of high-frequency electromagnetic wave is presented. The well-known TE{sub 01} mode in a cylindrical waveguide for the model of radiation fields and paraxial approximation for the wiggler field are used. Space charge field components are written in the Lagrange coordinates by the twice averaged Green`s functions of two equally charged infinitely thin discs. For that {open_quotes}compensating charges{close_quotes} method is applied in which an electron ring model is substituted by one with two different radii and signs discs. On this approach the initial Green`s functions peculiarities are eliminated and all calculations are considerably simplified. Coefficients of a twice averaged Green`s function expansion into a Fourier series are obtained by use of corresponding expansion coefficients of ...

Energy Technology Data Exchange (ETDEWEB)

A two-year demonstration run of a 500 C/100kgf/cm{sup 2}{center_dot}g high-efficiency waste-to-energy pilot plant has been started from February 1998; this plant represents as the final stage of the NEDO project of development of a high-efficiency waste-to-energy plant. Alloy 625 (SB444) and 310 HCbN tubings were selected for the 3rd and 2nd superheater of the pilot plant, respectively, and ten kinds of conventional and new solid-wall tubings, weld overlayed tubings, composite tubings, and cermet spray coated tubings were tested. By means of 6000-hour field corrosion test in three typical domestic plants, material life and corrosion environment for superheater tubings installed in the pilot plant were evaluated. Also, the effect of alloying elements Cr, Ni, Mo, corrosion rate law, etc. were investigated in detail. Furthermore, the design conception and basic performance of the pilot plant regarding pollution control and corrosion prevention were determined, based ...

Energy Technology Data Exchange (ETDEWEB)

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.)

British Library Electronic Table of Contents (United Kingdom)

Following Hurricane Katrina, the study of cantilevered sheet pile I-wall with gap or partial gap has become one of the central elements of the ongoing investigation pertaining to the re-building of hurricane protection systems in New Orleans, LA. Historically, the US Army Corps of Engineers (USACE) had mostly relied upon the Method of Planes (MOP) analysis procedure for slope stability analysis of I-wall systems. However MOP is a simplified procedure which does not satisfy total equilibrium. Nevertheless, MOP is still considered by USACE as a popular analysis tool because of its simplicity and ease of use in slope stability analysis. This paper demonstrates the applicability and suitability of MOP as a viable analysis tool for the analysis of New Orleans I-wall founded on layered cohesive ...

Energy Technology Data Exchange (ETDEWEB)

Purpose: To report the detection of con-compacted ventricular myocardium (NVCM) with MRI compared to echocardiography in 8 patients. Material and methods: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T{sub 1}-weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness ...

Energy Technology Data Exchange (ETDEWEB)

From the results of the In-Service Inspection (ISI) measuring the wall thickness of outlet (hot-leg side) feeder pipes performed at two Canadian nuclear power plants, Point Lepreau and Gentilly-2 in 1995 and 1996, respectively, the wall thinning degradation of feeder pipes at the bend part was found to be much more severe than expected. It has been well known that such wall thinning of feeder pipes is caused by the flow accelerated corrosion (FAC) which is one of the mechanical-chemical degradation mechanisms affecting the integrity of piping systems. For the Wolsung unit 1, the wall thickness measurements have been performed during every overhaul period since 1996. The wall thinning rates at the bends of outlet feeder pipes were assessed to exceed the design value. However, for the Wolsung units 2, 3 and 4, the wall thinning rates of all the outlet feeder pipes ...

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This paper investigates the dynamic recrystallization behavior of a directionally solidified (DS) nickel-base superalloy. The dynamic recrystallization occurs after the uncoated superalloy has been tested by tensile creep at elevated temperature for a long time. The dynamic recrystallization temperature is slightly lower than that of the static recrystallization. The dynamic recrystallization behavior of the DS superalloy below the static recrystallization temperature is mainly related to the high temperature oxidation and the free surface. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

An intake system is described for a direct fuel injection diesel engine having a cylinder block, at least one cylinder in the cylinder block, a piston in the cylinder having a recess on a top surface thereof, a cylinder head mounted on the cylinder block on top of the cylinder, a fuel injector adapted to directly inject fuel into a combustion chamber formed between the lower side of the cylinder head and the recess on the top surface of the piston, and below the injector, and a single exhaust passage opening to the combustion chamber at a location near the injector, the intake system comprising first and second intake passages in the cylinder head, the first and second intake passages are independent of each other and adapted to introduce air into the combustion chamber. The controller means are coupled to the second intake passage for controlling the flow of air therethrough.

Energy Technology Data Exchange (ETDEWEB)

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 ...

Energy Technology Data Exchange (ETDEWEB)

Several proposals have been made on the method of calculating generation of formaldehyde released from plywood. In calculating generation per hour of a volatile organic compound of adhesives or coatings using a chamber method, such models are frequently used that the generation is largest when the specimen is exposed in the chamber and that the generation attenuates with lapse of time. In the meantime, a number of studies for calculating formaldehyde generation from construction materials are often those determining a specific quantity of generation in a stationary state, while few studies are the observation of time series variation from immediately after the exposure into the chamber. Accordingly, the subject studies used lauan plywood as the samples and examined the method of calculating the change with lapse of time of the formaldehyde generation. (translated by NEDO)

Energy Technology Data Exchange (ETDEWEB)

Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating ...

UK PubMed Central (United Kingdom)

Mouse models for the study of autistic-like behaviors are increasingly needed to test hypotheses about the causes of autism, and to evaluate potential treatments. Both the automated 3-chambered...Full Text Available

Science.gov (United States)

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...

UK PubMed Central (United Kingdom)

BackgroundWith the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An unexpectedly high probability of collisions between the fission particles and the atoms in an ionization chamber along the entire particle track causes a strong fluctuation of the shapes of the Bragg curves. This fluctuation imposes an upper limit of the charge resolution ..delta..Z/Z which can be achieved.

Energy Technology Data Exchange (ETDEWEB)

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste.

International Nuclear Information System (INIS)

English 2009 p. 161-162 Brazil Paula, Viviane Silva de Almeida, Fabio

UK PubMed Central (United Kingdom)

Background and AimsIt is well known that genome size differs among species. However, information on the variation and dynamics of genome size in wild populations and on the early...Full Text Available

UK PubMed Central (United Kingdom)

AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available

Science.gov (United States)

The dynamic response characteristics of the VAWT rotor are important factors governing the safety and fatique life of VAWT systems. The principal problems are ...

Science.gov (United States)

... 23 Milstar 25 A Notional Battlespace For Dynamic Wireless Network Simulation/Testing ... Figure 16: GPS Satellite 23 Figure 17: Milstar Satellite 25 ...

Energy Technology Data Exchange (ETDEWEB)

Discusses design of unconventional pneumatic forms for construction of monolithic liners in mine roadways driven by drilling and blasting. The forms were developed for construction of the municipal subway in Leningrad. They were successfully tested in the Pavlogradugol' mines for construction of chambers situated at shaft bottom at depths of 420 m. The chambers were situated in unstable rock strata. A set of pneumatic forms consisted of 4 to 7 units, each 0.4 m thick and 1.2-2.2 m long. Air pressure was 0.03 MPa, installation time was about 20 min. Service life of pneumatic forms ranged from 3 to 4 years.

Energy Technology Data Exchange (ETDEWEB)

Apparatus and a method of introducing a primary fuel, which may be a coal water slurry, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure. 19 figures.

Energy Technology Data Exchange (ETDEWEB)

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

Energy Technology Data Exchange (ETDEWEB)

A large scintillation chamber of 6.7 l volume for direct radon concentration measurements in gas is presented. With two 5 in. photomultipliers on opposite sides, working in coincidence, a concentration as low as about 0.5 mBq/l is detectable with 10% standard deviation after 1000 min measuring time. With the achieved background count rate of 0.42 counts/min and the counting efficiency of 0.607 for [sup 222]Rn and its progenies the absolute minimal detectable specific activity is reached with 0.17 mBq/l at about 12 000 min. The method to determine this minimum detectable activity is outlined. ((orig.))

International Nuclear Information System (INIS)

Quantitative gated SPECT (QGS) was evaluated in 7 normal volunteers and 31 patients with cardiac diseases. Adequate cut off value of a prefilter was 0.45. In phantom, the left ventricular volume value was 93.9% of determined value by 180-degree projection in L type and 98.8% by 360-degree projection in opposed type. In normal volunteers, LVEF measured by QGS program related to value by first pass method. As for functional map, regional EF and wall motion decreased at the septum side, and wall thickening at base side of heart. Good correlation was recognized (p<0.0001) between blood flow image and functional map (regional EF and wall thickening). In 20 cases of acute myocardial infarction, lesion was detected conspicuously in regional EF and wall motion. The accuracy of coronary arterial stenosis improved in functional map (regional EF 92%, wall motion 92% and ...

Energy Technology Data Exchange (ETDEWEB)

It is postulated that a break of a thin-walled pipe does not cause a subsequent break in the pipe in the vicinity of a plastic hinge even when the wall is weakened by a 60 circumferential crack of a depth of 30% of the wall thickness on the tension side. This pipe behavior is the result of plastic buckling in the compression side and applies to pipes of diameter-to-thickness ratio larger than 20. For this type of pipe, the axial strains decrease with increasing diameter-to-thickness ratio in the tension side. As the pipe is only loaded in one direction, there is no cyclic behavior that can trigger a subsequent break. (orig.)

International Nuclear Information System (INIS)

Several recent experiments on micro- (or nano-) structured samples of ferromagnetic materials are introduced. Magnetization reversal phenomena are investigated on submicron wire samples of trilayer structure using the giant magnetoresistance effect. Domain wall movements are sensitively monitored by resistivity measurements and the velocity of propagation is determined. The contribution of domain wall to the resistivity is argued from the results on artificially designed samples of a spring-magnet system. In circular dots of permalloy, the existence of vortex magnetization is confirmed and the reversal of the vortex core magnetization is studied from magnetic force microscopy measurements. (author)

Energy Technology Data Exchange (ETDEWEB)

The paper describes an analytical study of two parallel-flowing boundary layers of free and forced convection modes on the facing sides of a vertical thin wall. The two layers are analyzed separately within the framework of boundary layer theory, and coupled by the matching conditions at wall. Numerical data are obtained for a wide range of a dimensionless conjugation parameter {zeta} relating the heat transfer effectiveness of two convection modes. Based on these data, an expression for calculating the conjugate mean Nusselt number as a function of {zeta}-parameter is found by means of a curve-fitting method. (orig.)

International Nuclear Information System (INIS)

This thesis was carried out at Forsmark Nuclear Power Plant. The power plant in Forsmark consists of three boiling water reactors (BWR) which produce about 17% of Swedish electricity. In a BWR the nuclear reactions are used to boil water inside the reactor vessel. The water works both as a coolant and as a moderator and the resulting steam is used directly to run the turbines. A problem when running a BWR at low flow conditions is the density wave oscillations that might occur to the water flow inside the fuel assemblies. These oscillations arise due to the connection between power and flow rate in a heated channel with two-phase flow. In order to improve the stability performance of the channel an orifice plate is placed at the inlet of each fuel assembly. Today these orifice plates have sharp edges and a constant resistance coefficient. Experimental work has been done with progressive orifices, the edge of which is half-oval in shape. The advantage of progressive orifices is the ...

Science.gov (United States)

... necessary to allow for the effata nr the finits size of the oressure tranaducer on both the root mean square and power spectral density measurements ...

Science.gov (United States)

Eckert, B., "Axial Kompressoren und Radial Kompressoren," Springer. Verlag, Berlin, 1953. 3. Lebot, Y., et al., "Theoretical and Experimental Determination ...

Science.gov (United States)

... After strip- ping off the chloroform, the dibromo ethyl (EDBEB) compounds are separated from the m-BDBEB using a thin film evaporator. ...

Science.gov (United States)

... Hydro- gen gas is fed through a temperature- controlled Pd-Ag leak 161 into a cylindrical double-walled Pyrex bulb, 15 cm long and 1.9 cm in ...

CERN Document Server

This mechanical version was soon after changed into a hydraulic jack one (the reason being a number of serious constructional defects).

Science.gov (United States)

... 2.2.1 Polymerization of DVB Under Pressure DVB was polymerized at 300*C in thin-walled Pd-Ag capsules at pressures up to 60,000 psi. ...

Science.gov (United States)

was deemed adequate and a cooling system designed utilizing the Melcor CP2-15- 10B thermoelectric module. Wall temperature achieved with this system was - 36 ...

Energy Technology Data Exchange (ETDEWEB)

Using a quasi-static approach valid for Stefan numbers less than one, we derive approximate equations governing the movement of a phase change front for materials which generate internal heat. These models are applied for both constant surface temperature and constant surface heat flux boundary conditions, in cylindrical, spherical, plane wall and semi-infinite geometries. Exact solutions with the constant surface temperature condition are obtained for the steady-state solidification thickness using the cylinder, sphere, and plane wall geometries which show that the thickness depends on the inverse square root of the internal heat generation. Under constant surface heat flux conditions, closed form equations can be obtained for the three geometries. In the case of the semi-infinite wall, we show that for constant temperature and constant heat flux out of the wall conditions, the solidification layer ...

Science.gov (United States)

Protein isolated from hen egg-white and functions as a bacteriostatic enzyme by degrading bacterial cell walls. First enzyme ever characterized by protein ...

Science.gov (United States)

S.M. Goltz; NASA Goddard Space Flight Center, Forest Ecosystem Dynamics Project ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

... Netherlands Kormendy, J. Dominion Astrophysical Observatory, Victoria, British

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Norwegian Open Research Archives (NORA)

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Indian Institute of Science Theses & Dissertations (India)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

Three aspects of the physical geographic environment of the Amazon Basin are considered: (1)

KoreaScience (Korea)

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CERN Document Server

In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of limit theorems for this object.

Science.gov (United States)

The authors solve the two-dimensional stefan problem of solidification in a half-space, where the heat flux at the wall is a slightly varying function of positioning along the wall, by means of a large Stefan number approximation (which turns out to be equivalent to a small time solution), and then by means of the Heat Balance Integral Method, which is valid for all time, and which agrees with the large Stefan number solution for small times. A representative solution is given for a particular form of the heat flux perturbation.

Wastenet

... The composite ground floor is suitable for support to all types of wall construction and can be used equally well on strip footings or mini-pile foundations . The light steel edge beams provide the accurate template required for internal timber or light steel wall frames to minimise fitting time and eliminate rework. The floated slab surface will accept floor finishes directly and thermal insulation can be easily fitted beneath ...

International Nuclear Information System (INIS)

The effectiveness of an acrylic latex wall sealant in limiting the escape of radon from rock in underground mines is the subject of this paper. Application of the latex as a two-coat system over a fillter coat of gunite produced a reduction of radon concentration from an initial level of 80 to 100 pCi/L to a final average of 25 to 30 pCi/L under similar conditions.

Science.gov (United States)

Analytical solutions are derived for a flow in a semi-infinite vertical porous medium with heat and mass transfer. When the temperature and mass concentration are uniform a constant pressure is possible and sustains a fully developed flow. Thereafter there is a small perturbation on the wall temperature and concentration and the subsequent two-dimensional problem is tackled for a large Prandtl number, free convection parameters and small Reynolds number. The heat transfer rate at the wall is discussed quantitatively.

Energy Technology Data Exchange (ETDEWEB)

Ti honeycombs with the side of 800 and 400 nm were fabricated by focused ion beam (FIB), though the surfaces of the bottom and wall of the Ti honeycombs were rough, as compared with the surfaces of the bottom and wall of the Si honeycomb. It is demonstrated that the nanoscale Ti components can be fabricated in a short time by FIB.

Energy Technology Data Exchange (ETDEWEB)

The Doublet III device is operating with an extensive system of plasma limiters and wall protective armor. Operations with up to 8MW of neutral beam power and 1.5MA plasma current are planned. Design and operational performance of the following systems are discussed: 1. Water-cooled graphite moveable limiter. 2. Water-cooled graphite fixed limiter and neutral beam wall armor. 3. Radiatively cooled Inconel divertor plates.

International Nuclear Information System (INIS)

During the operation of a tokamak, the first wall elements suffer very high heat fluxes. Heat is removed by internal cooling by means of water, helium or fluid metal. The resulting inhomogeneous temperature field cause internal stresses which, due to the pulsed operation are of cyclic nature. Additional mechanical stresses in the first wall may be caused by disruptions or vertical plasma movements. During theses events high currents are induced in the metallic part of the first wall which by their interaction with the magnetic field of the tokamak lead to mechanical forces. These electromechanical stresses may lie beyond the yield stress of the structural material. From the interaction of thermal and mechanical forces, a complex stress state is achieved which under certain circumstances may lead to premature failure and/or to progressive plastic deformations (ratcheting). In order to study the boundary conditions for the ...

Energy Technology Data Exchange (ETDEWEB)

To assess the potential of CT in evaluating the histological severity of acute appendicitis in comparison with surgical and pathological findings. The CT images of 75 patients with surgically proven appendicitis, including 10 cases of catarrhal, 34 of phlegmonous, and 31 of gangrenous appendicitis, were retrospectively analyzed for the following five CT findings: hazy periappendiceal densities, enlarged appendix, increased enhancement of the appendiceal wall, increased enhancement of the periappendiceal intestinal wall, and deficiency of the appendiceal wall. By comparing all the CT findings and the pathological severity of appendicitis (catarrhal, phlegmonous, and gangrenous), the prevalence of the five CT findings was calculated for each pathological category. Abnormal CT findings were noted in only one case of catarrhal appendicitis. Increased enhancement of the appendiceal wall was observed in all ...

Energy Technology Data Exchange (ETDEWEB)

Gas quenching for the hardening of steel parts is a lower-pollution alternative to quenching in quenchants such as oil or salt. As the surfaces of the cooled parts remain clean after gas quenching, there is no need to wash them after heat treatment, which reduces the consumption of oils and detergents. The fire risk and ventilation requirements of oil quenching are eliminated. In addition, some trials have shown that gas quenching has a positive effect on distortion, representing a saving in finishing work and thus a reduction in costs. Today, gas quenching is used almost solely in vacuum furnaces. Quenching is normally performed in the same chamber as heating, which means that besides quenching the batch, the quenching system must also remove heat from the heating elements and insulation of the furnace. Previous trials performed by IVF have shown that gas quenching with helium of ball bearing and carburizing steels (and other steels) in sizes up to 25 mm at ...

International Nuclear Information System (INIS)

A complete heavy ion identification system in heavy ion reaction studies consists, in general, of: 1) a position sensitive avalanche counter, and 2) ionization chamber to obtain total energy as well as a heavy ion identifier signal (such as the E#DELTA#E signal from a E-#DELTA#E type detector or the height of the Bragg peak that scales as Z of the heavy ion in a Bragg curve ionization chamber). In addition, a time-of-flight information may be needed to resolve the masses of the ions. With this motivation in mind, a composite detector system consisting of a Bragg curve spectroscopy ionization chamber (BCS-IC) and a one dimensional position sensitive parallel grid avalanche counter (XPS-PGAC) has been developed and used successfully at the BARC-TIFR pelletron accelerator facility. The design and performance of this gas detector system are reported. (author). 4 refs., 2 figs.

Energy Technology Data Exchange (ETDEWEB)

The United States Air Force School of Aerospace Medicine (USAFSAM) tests the quantitative fit of masks which are worn by military personnel during nuclear, biological, and chemical warfare. Subjects are placed in a Dynatech-Frontier Fit Testing Chamber, salt air is fed into the chamber, and samples of air are drawn from the mask and the chamber. The ratio of salt air outside the mask to salt air inside the mask is called the quantitative fit factor. A motion-time study was conducted to evaluate the efficiency of the layout and work method presently used in the laboratory. A link analysis was done to determine equipment priorities, and the link data and design guidelines were used to develop three proposed laboratory designs. The proposals were evaluated by projecting the time and motion efficiency, and the energy expended working in each design. Also evaluated were the lengths of the equipment links for each proposal, and ...

Energy Technology Data Exchange (ETDEWEB)

Apparatus and methods for generating heat and electricity from the consumption of a variety of aluminum products comprise: (A) a reaction chamber containing an aqueous electrolyte solution and adapted for introduction therein of aluminum pieces of various shapes and sizes up to a certain maximum predetermined size and for effecting a chemical reaction between said aqueous electrolyte and said aluminum pieces yielding aluminum hydroxide and an intermediate reactant; (B) means for feeding said aluminum pieces into said reaction chamber in small quantities upon demand; (C) means for removing the heat generated in said chamber as a result of said reaction; (D) means for removing said aluminum hydroxide reaction product; and (E) means for oxidizing said intermediate reactant in an electrochemical cell, thereby generating electrical energy. The intermediate reactant is preferably hydrogen or zinc. The latter may be used in a ...

CERN Document Server

The front-end electronics system for the anode signals of the CMS Endcap Muon cathode strip chambers has about 183000 channels. The purposes of the anode front-end electronics are to acquire precise muon timing information for bunch crossing number identification at the Level-1 muon trigger system and to provide a coarse radial position of the muon track. Each anode channel consists of an input protection network, amplifier, shaper, constant-fraction discriminator, and a programmable delay. The essential parts of the electronics include a 16-channel amplifier-shaper-discriminator ASIC CMP16 and a 16-channel ASIC D16G providing programmable time delay. The ASIC CMP16 was optimized for the large cathode chamber size (up to 3 x 2.5 m2) and for the large input capacitance (up to 200 pf). The ASIC combines low power consumption (30 mW/channel) with good time resolution (2 - 3 ns). The del ay ASIC D16G makes possible the alignment of signals with an ...

Energy Technology Data Exchange (ETDEWEB)

A stable power system stabilizer (PSS) based on the inverse dynamics of the controlled system using an artificial neural network (ANN) is suggested to enhance the dynamic performances of a power system. First, an output feedback control law is driven with some conditions satisfied, which guarantees the internal stability and robustness against the asymptotically stable external disturbances. Then the control law is implemented using the inverse dynamics of the controlled plant. The inverse dynamics of the controlled plant is identified by an ANN, inverse dynamics neural network (IDNN), off-line. The pole-shifting technique and a scaling factor are introduced for the control system to meet the conditions for internal stability and robustness. The proposed controller is applied to a typical single-machine infinite-bus power system. Simulation results under various operation conditions ...

CERN Document Server

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

International Nuclear Information System (INIS)

The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required. (orig.).

International Nuclear Information System (INIS)

Research was performed to assess the feasibility of barrier membrane substances, for use within mining or associated high risk environments, in restricting the diffusion transport of radon gas quantities. Specific tests were conducted to determine permeability parameters of a variety of membrane materials with reference to radon flow capabilities. Tests were conducted both within laboratory and in-situ emanation environments where concentrations and diffusion flows of radon gas were known to exist. Equilibrium radon gas concentrations were monitored in initially radon-free chambers adjacent to gas sources, but separated by specified membrane substances. Membrane barrier effectiveness was demonstrated to result in reduced emanation concentrations of radon gas within the sampling chamber atmosphere. Minimum gas concentrations were evidenced where the barrier membrane material was shown to exhibit lowest radon permeability characteristics.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a low emission duel fuel engine system. It comprises: a dual fuel engine having a combustion chamber; a fuel oil supply connected to the engine; a fuel gas supply connected to the engine; and means connected between the fuel oil supply and the engine for injecting fuel oil into the engine. The means connected between the engine and fuel oil supply limiting the injection of fuel oil to the combustion chamber to pilot ignition quantities only, wherein the limiting means includes means for limiting the injection of fuel oil such that the exhaust emission of NO{sub x} is at an emission rate of less than 1 GM/PH-HR, whereby the exhaust emission performance of the dual fuel engine is enhanced.

Energy Technology Data Exchange (ETDEWEB)

A passive dosemeter, based on a Makrofol ED track detector covered with aluminized Mylar, enclosed in diffusion chamber, has been used for radon concentration studies. Detectors have been irradiated, using a {sup 241}Am source, at different energies and fluences in order to obtain the electrochemical etching conditions that allow the optimum registration of alpha particles having energies over 3 MeV. Thirty dosemeters have been sent to the UK National Radiation Protection Board (NRPB) Radon Environmental Chamber for calibration. The sensitivity of the dosemeter has been calculated. Several dosemeters have also been exposed in houses and dwellings in the Barcelona and Madrid areas for monitoring. Values for radon concentration in the areas under study are presented. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper presents a reformer prototype for the production of the necessary H{sub 2} to supply a 5 kW PEMFC and its first results. The fuel processor consists of an OSR and a WGS and a PROX reactors. The design of the system was carried out with a one-dimensional model. The mixture chamber was specially studied with a CFD code (Fluent), taking into account the effect of fuel evaporation and the cool flame process. The aim of the designed facility is to be able of characterising each component and controlling each working parameter. Eventually, using diesel as fuel, results from the mixture chamber, OSR, WGS and PROX reactors are presented. It also includes conclusions and future works. (authors)

British Library Electronic Table of Contents (United Kingdom)

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...

Energy Technology Data Exchange (ETDEWEB)

An apparatus for measuring the overall decontamination factors of first and second filters located in a plenum. The first filter separates the plenum's upstream and intermediate chambers. The second filter separates the plenum's intermediate and downstream chambers. The apparatus comprises an aerosol generator that generates a challenge aerosol. An upstream collector collects unfiltered aerosol which is piped to first and second dilution stages and then to a laser aerosol spectrometer. An intermediate collector collects challenge aerosol that penetrates the first filter. The filtered aerosol is piped to the first dilution stage, diluted, and then piped to the laser aerosol spectrometer which detects single particles. A downstream collector collects challenge aerosol that penetrates both filters. The twice-filtered aerosol is piped to the aerosol spectrometer. A pump and several valves control the movement of aerosol within the ...

International Nuclear Information System (INIS)

A nonlinear mathematical model is presented of a WWER-440 nuclear power plant horizontal steam generator. On the proposed model is based a computer program for investigating transients in steam generators during loss of coolant accidents. Processes taking place at the primary side of the steam generator are described by a set of partial differential equations while those at the secondary side of the steam generator are described by plain differential equations with the variables being complex time functions. The model takes account of the coolant as both a single- and two-phase medium, of changes in the direction of the primary coolant flow and of changes in the direction of heat transfer. Heat transfer through the wall is based on a simple model of heat transfer through a thin-walled tube and includes a correction for the heat resistance of the wall. (author).

Energy Technology Data Exchange (ETDEWEB)

Heat transfer experiments were performed in the post-CHF two-phase flow regime in a vertical tube. The tube inside diameter was 7.75 mm, and the boiling fluid was R-113. The experiments were performed at steady state by means of liquid heating of the test tube. Wall superheats were maintained below 70 C for heat exchanger/steam generator application. The mass flux range of the data was 379-816 kg m{sup -2} s{sup -1}. The use of R-113 significantly extended the property range of the existing low wall-superheat data base. Experimental data are presented in tabular as well as graphical form, and the results were used with low wall-superheat data from other fluids to add generality to a predictive heat transfer correlation. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Combined gas and steam turbine processes based on direct coal firing show a high thermal efficiency. At RWTH Aachen, University of Technology, an experimental test furnace has been built to investigate the pressurized pulverized coal combustion (PPCC). The PPCC-facility has been constructed as a slag tap furnace. Particles hitting the walls at temperatures above the melting point cause slagging depositions and create a film flowing down the reactor walls. As a part of the PPCC-program different mathematical models have been developed and implemented into the CFD-code FLUENT to predict the behavior of slag films at the furnace walls. Numerical strategies and the mathematical models used are described in detail. 12 refs., 9 figs.