Science.gov (United States)

% In this work we investigated, in the Smooth Particle Hydrodynamics (SPH) framework, the development of spiral structures and shock fronts in the radial flow of accretion discs in close binary systems. These shock waves take place when the initially supersonic radial flow penetrating the disc bulk, reduces substantially its speed becoming suddenly subsonic. To this purpose, keeping constant the mass of the compact primary (M1 = 1 MO ), the separation between the two components and the injection speed at the inner Lagrangian point L1 (close to the local sound speed), we carried out 2D SPH simulations for four values of the stellar mass ratio M2/M1. We worked out 2D models because the damping effect of the artificial viscosity is too strong in 3D. Furthermore, the 2D environment seems the most suitable in order to evidence shock fronts in highly compressible ...

Science.gov (United States)

... Accession Number : AD0164404. Title : Ball and Roller Bearing Retainer Improvement for High Speed Operation. Descriptive Note : Patent,. ...

KoreaScience (Korea)

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UK PubMed Central (United Kingdom)

PurposeTo describe ocular findings for a 34-year-old man with chronic solar retinopathy using high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT).Full Text Available

UK PubMed Central (United Kingdom)

A high-speed fiber-based network for the transmission and display of digitized full-motion cardiac images has been developed. Based on Asynchronous Transfer Mode (ATM), the network is scaleable, meaning...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The UIC High Speed Department's flagship event is the World Congress on High Speed Rail held approximately every three years. This year's congress will take place in Amsterdam from 17 to 19 March 2008. (orig.)

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

roller bearing with a one-piece inner ring. The lubricant experimental data on high-speed roller .... roller bearing. The outer ring of the test bearing was ...

Science.gov (United States)

... Peripherals: 1 VT100 terminal and 1 high-speed ... Customer in ASP time Queue data ME ... TREATMEN OF RANDOMNESS: Stochastic, Monte Carlo. ...

International Nuclear Information System (INIS)

The ecological effects of acid mine drainage were investigated during the summer of 1993 on St. Kevin Gulch, a headwater stream near Leadville, Colorado. The stream currently receives acidic water from an abandoned mine. The pH downstream of the mine is between 3.5 and 4.5, and several metals exceed concentrations toxic to aquatic organisms. Zinc is present at especially high concentrations (1 to 10 mg/L) Furthermore, the stream bottom is covered with a thick layer of iron hydroxide precipitates. Effects on stream biota have been dramatic. Aquatic flora in the affected reach is limited to a green filamentous alga, Ulothrix subtilissima. Macroinvertebrate densities are significantly lower in the affected reach (mean = 99 indiv/m"2; SD = 88 indiv/M"2) compared to an upstream (pristine) reference reach (mean = 1,735 indiv/m"2; SD = 652 ...

Energy Technology Data Exchange (ETDEWEB)

A high-speed light-Diesel engine with direct injection has been developed by the Institute of Combustion Engines, Graz. Thanks to light construction throughout, exhaust gas supercharger and noise-reduced composition a Diesel engine could be built that is comparable to Otto-cycle engines as regards performance, weight, aggregate size and noise production but far superior to these with respect to fuel consumption and exhaust gas emission.

International Nuclear Information System (INIS)

The surface permeability of concrete walls and floors in houses was measured with a specially designed permeameter, based on measuring the air-flow induced by a pressure difference across a temporary test seal applied to a surface. The permeability of bulk concrete is 10"-"1"6 m"2. Areas free of surface defects had permeability ranging from 10"-"1"4 to 10-"1"6 m"2. However, surface defects are common on concrete wall surfaces, which increase the permeability to >10"-"1"2 m"2. This is too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Satisfactory seals require either extended contact width or mechanical removal of the surface layer. (orig.). (2 figs., 1 tab.).

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)

International Nuclear Information System (INIS)

Momentum- and speed-dependent Maxwell-Boltzmann equilibrium distributions have been derived for tachyons and compared with the corresponding relativistic distributions. This is followed by a calculation of the mean, most probable and r.m.s. speeds for both the relativistic and tachyonic distributions. The ideal gas of tachyons is discussed, including calculations of the internal energy and entropy. In each case a comparison is made with the corresponding bradyonic results. It is found that tachyons behave just like bradyons in the high-temperature limit, but have markedly different behaviour at low temperatures.

Energy Technology Data Exchange (ETDEWEB)

In this paper, a complete solution of the steady-state Newton-Euler equations describing the motion of the balls in high speed thrust bill bearings is presented. Kinematic equations are derived and used as ancillary equations to obtain the numerical solution of the Newton-Euler equations. This differs from previously reported work where extraneous assumptions (instead of kinematic analysis) are used to allow solutions of these equations. It is shown that the no-slip condition for the ball motion reported in the literature is based on an unnecessary assumption. The correct form of the condition is developed and used in the analysis of the ball motion. The analysis shows the importance of contact angle on both ball motion and contact force. An approximate theory is then developed for determining the optimum contact angle that would result in minimum contact force in high speed ball bearings. The results ...

UK PubMed Central (United Kingdom)

1. At high running speeds, the step frequency becomes lower than the apparent natural frequency of the body's bouncing system. This is due to a relative increase of the vertical component of the muscular...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This paper describes high speed rolling and gauge control in cold tandem mill for ultra-thin gauge strip at the Chiba Works of Kawasaki Steel Corporation. To improve the plate-out property of rolling oil, cationic polymeric coagulant was prepared. Rolling oil with cohesion independent of inorganic inclusions or phosphatide was developed, to improve the lubrication for cold rolling, remarkably. In addition, a low-cost Ti-enhanced work roll having high wear resistance and excellent grindability was developed. Rolling can be conducted at the optimal rolling roughness and operation can be performed at the highest rolling speed independent of the rolling treatment amount. Rolling speed at 2800 m/min was confirmed by developing the rolling oil with excellent lubrication and the work roll having high wear resistance. For the improvement of strip thickness accuracy at ...

Energy Technology Data Exchange (ETDEWEB)

The modification of a Ford 7600 turbocharged diesel engine to a dual fuel engine using methane as the supplementary fuel has been carried out. The paper describes the preliminary work of dual fuel control. Two systems are examined and their behaviour is presented.

British Library Electronic Table of Contents (United Kingdom)

The association between invasive and native species varies across spatial scales and is affected by phylogenetic relatedness, but these issues have rarely been addressed in aquatic ecosystems. In this study, we used a non-native, highly invasive species of Poaceae (tropical signalgrass) to test the hypotheses that (i) tropical signalgrass success correlates negatively with success of most native species of macrophytes at fine spatial scales, but its success correlates positively or at random with natives at coarse spatial scales, and that (ii) tropical signalgrass is less associated with native species belonging to the family Poaceae than with species belonging to other families (Darwin?s naturalization hypothesis). We used a dataset obtained at fine (0.25?m2) and coarse (ca. 1,000?m2) sca...

International Nuclear Information System (INIS)

This paper reports on the electron current to a Langmuir probe in a moving high-pressure plasma. The plasma is an atmospheric-pressure propane flame, and the probe's speed relative to the plasma is varied from 10 to 30 ms"-"1. The current is linearly dependent on the speed and appears to be comprised of two components - one driven by diffusion and the other by convection. A model is devised which can be used to measure the electron density. By comparing the density computed from this model to that measured from the ion current, it has been possible to measure the electron mobility in the flame gases. The value obtained here is in good agreement with theoretical calculations found in the literature.

Energy Technology Data Exchange (ETDEWEB)

Better properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries. However, the magnesium alloy thin sheets used in rechargeable batteries were produced by ingot casting and rolling. That technology was so complex and the cost was high. Rapidly solidification by melt spinning is an effect way to solve that problem. In this paper, the technology of rapidly solidified (RS) ribbons in Mg-3%Al-1%Zn-0.2%Mn alloy has been investigated using melt spinning technique. The effect of wheel speed on thickness and microhardness of the ribbons is presented. Microhardness is found to increase with the wheel speed. Rapidly solidification leads to small grains (1{proportional_to}2 {mu}m). The plasticity of the ribbons was well. The quantity of Mg{sub 17}Al{sub 12} decreases with the increase in wheel speed. When the wheel speed reaches 1600 rpm, no Mg{sub ...

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations were performed to assess the effects of different shaped obstructions on flame propagation in a rectangular confinement, 235 mm in height, with a 1000 x 950mm cross section and a large top-venting area of 1000 x 320mm. Four different single obstacles were used: rectangular, cylindrical, triangular, and square cross-sections with blockage ratios of 5 and 10%. Temporally resolved flame front images were recorded by a high-speed video camera to investigate the interaction between a propagating flame and the obstacle. The local flame displacement speeds and their probability density functions (pdfs) were obtained for the different obstacles. Before the freely propagating flame impinges on the obstacle, the flame propagation speed remains close to the laminar burning velocity, regardless of the obstacles used. As the propagating flame impinges on the obstacle, the local propagation ...

Energy Technology Data Exchange (ETDEWEB)

The factors influencing premixed burning and the importance of premixed burning on the exhaust emissions from a small high-speed direct-injection diesel engine were investigated. The characteristics of premixed and diffusion burning were examined using a single-zone heat-release analysis. The mass of fuel burned in premixed combustion was found to be linearly related to the product of engine speed and ignition-delay time and to be essentially independent of the total amount of fuel injected. Accordingly, the premixed-burned fraction increased with increasing engine speed, with decreasing fuel-air ratio and with retarding injection timing. The hydrocarbon emissions did not correlate well with the premixed-burned fraction. In contrast, the oxides of nitrogen emissions were found to increase with decreasing premixed-burned fraction, indicating that diffusion burning, and not premixed burning, is the primary source of oxides of ...

Energy Technology Data Exchange (ETDEWEB)

10 papers are presented with the following titles: coal fueled diesel engine development update at GE transportation systems; features and performance data of Cooper-Bassemer coal-fueled six-cylinder LSB engine; preliminary test data and systems analysis of a high pressure coal fuel processor/engine system concept; study for coal-water-slurry fuel combustion in a high speed diesel engine; design and operation of a medium speed 12-cylinder coal-fueled diesel engine; progress on the investigation of coal water slurry fuel combustion in a medium speed diesel engine: part 5 - combustion studies; injection characteristics of coal-water slurries in medium speed diesel equipment; coal-water slurry spray characteristics of a positive displacement fuel injection system; novel injector techniques for coal-fueled diesel engines; and investigation of break-in wear, ring ...

International Nuclear Information System (INIS)

Sealants for radon-resistant foundation construction must seal the gap between concrete sections. Modern sealants have such low permeability that seal performance depends only on the permeability of the material that contacts the sealant. The surface permeability of concrete walls and floors was measured by a specially designed permeameter, which measures the airflow induced by a pressure difference across a temporary test seal applied to the surface. The permeability of bulk concrete is about 10"-"1"5 m"2. Areas free of surface defects had surface permeability ranging from 10"-"1"4 to 10"-"1"6 m"2. However, surface defects are common on concrete wall surfaces, which increase the permeability to >10"-"1"2 m"2, too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Radon-resistant seals ...

CERN Document Server

we report an ultrafast synchrotron x-ray phase contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. We demonstrate that there exist great similarities in the phenomenology of primary breakup with that of the secondary breakup. Especially, a membrane-mediated breakup mechanism dominates the breakup process for a wide range of air speeds. This finding reveals the intrinsic connections of these two breakup regimes and has deep implications on the unified theoretical approach in treating the breakup mechanism of high speed liquid jet.

Energy Technology Data Exchange (ETDEWEB)

As part of a comprehensive simulation of a prototype locomotive propulsion system, a detailed model has been developed which predicts the dynamic response of an experimental 2-stroke, turbocharged and intercooled diesel engine. Engine fueling and brake torque are computed from regression equations derived from an extensive data base. Corrections are applied to the calculated steady-state torque to account for dynamic deviations of in-cylinder trapped air-fuel ratio from the steady-state value. The engine simulation accurately represents the operation of the turbo-charger, which is gear-driven at low turbocharger speeds, and freewheels through an overrunning clutch when exhaust energy accelerates the turbocharger beyond its geared speed. Engine fueling level, ie, rack, is determined from a dynamic simulation of an electrohydraulic governor which responds to the difference between the desired and the actual engine speeds. The ...

Science.gov (United States)

Photoacoustic microscopy (PAM) offers label-free, optical absorption contrast. A high-speed, high-resolution PAM system in an inverted microscope configuration with a laser pulse repetition rate of 100,000 Hz and a stationary ultrasonic transducer was built. Four-dimensional in vivo imaging of microcirculation in mouse skin was achieved at 18 three-dimensional volumes per second with repeated two-dimensional raster scans of 100 by 50 points. The corresponding twodimensional B-scan (50 A-lines) frame rate was 1800 Hz, and the one-dimensional A-scan rate was 90,000 Hz. The lateral resolution is 0.23+/-0.03 ?m for Au nano-wire imaging, which is 2.0 times below the diffraction limit.

Energy Technology Data Exchange (ETDEWEB)

This study tried to reduce NO{sub x} and particulate emissions simultaneously in a high speed direct-injection diesel engine. Fuel-rich combustion was used to reduce NO{sub x} emission at initial combustion stage and high turbulence combustion was used to reduce particulate emission at diffusion combustion stage. Experiments were carried out to investigate the effects of high squish combustion chambers with small throat on combustion process and exhaust emissions. Results showed that in the high squish combustion chamber, both NO{sub x} and particulate emissions reduced with retarded injection timing. Endoscopic high speed photography was employed to analyze experimental results. In the original combustion chamber at the early combustion stage, the high luminosity flame tended to spread out of the cavity. Fuel-rich ...

Energy Technology Data Exchange (ETDEWEB)

Characterization of the electron beam's properties will be a major task after the upgrade of the Los Alamos Free-Electron Laser (FEL) Facility with a photoelectric injector (PEI) and increased acceleration capability to 40 MeV. Adjustments to the previous diagnostics package that address the lower beam emittance, higher energy, and wakefield source reduction issues will be discussed. 6 refs., 8 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The B-Factory which is constructed by National Laboratory for High Energy Physics is the device for elucidating the breakdown of symmetry of matter and antimatter by studying the behavior of B mesons which are generated in large quantity when the electrons and the positrons which are accelerated to light velocity level are collided. In order to maintain electron beam-positron beam bunch circling the ring at light velocity stably, the instability of the coupled bunch must be overcome. For this purpose, the ultrahigh speed beam position digital feedback control system was developed. This system is composed of the high speed input-output substrate using GaAs LSI, the feedback computation substrate using complementary metal oxide semiconductor and the memory mounted on it, and the real time operation device. The development of both substrates and their functions are explained. The real time data collection ...

International Nuclear Information System (INIS)

The influence of chemical composition and heat treatment on a low-carbon steel, chromium steel and high speed steel has been examined by polarisation curves and electrochemical parameters deduced from the Tafel plots. The electrochemical corrosion resistance, which is small between the as-received steels become greater after heat treatment, following the order: carbon steel < chromium steel #approx# high speed steel. To explain these differences, the nano- and microstructure of the steels has been characterized by the ex situ techniques of atomic force microscopy and optical microscopy, before and after surface etching with Nital (a solution of 5% HNO_3 in ethanol). This causes preferential attack of the ferrite phases showing the carbide phases more clearly. From these nanostructural studies it was possible to better understand why the passive films formed on chromium steel and ...

Energy Technology Data Exchange (ETDEWEB)

For the application of dynamic neutron radiography to the two-phase flow research using HANARO, several experimental items to which the radiography technique is beneficial were identified through the review of the outputs from the related researches and the discussions with experts. Also, the investigation of the equipments including the beam port, camera and converter was made and a hardware and a software for image processing were equipped. It was confirmed that the calibration curve for the attenuation of neutron beam in fluid which is required for the two-phase flow experiment could be obtained by the computer code calculation. Based on the investigation results on the equipment and the results from the measurement of BNCT beam characteristics, a high speed camera and an image intensifier will be purchased. Then, the high speed dynamic neutron radiography facility for two-phase flow experiments will ...

Energy Technology Data Exchange (ETDEWEB)

Recognizing that a high percentage of transmission-line faults are single-phase to earth and temporary in nature, provides the impetus for considering single-pole switching as a means to enhance the reliability of EHV transmission systems. The effectiveness of single-pole switching schemes is largely determined by the speed with which the secondary arcs extinguish, and hence allow system restoration. Simulation techniques that enable better prediction of the faulted-system response are of obvious importance to the design and assessment of the various single-pole switching scheme applications. In this thesis, digital methods are developed to enable the faulted response of EHV systems to be simulated for a variety of different single-pole switching schemes. These include conventional single-pole switching, the hybrid method of autoreclosure, the neutral switched reactor, and the High Speed Grounding ...

Energy Technology Data Exchange (ETDEWEB)

Modern scientific computing involves organizing, moving, visualizing, and analyzing massive amounts of data from around the world, as well as employing large-scale computation. The distributed systems that solve large-scale problems will always involve aggregating and scheduling many resources. Data must be located and staged, cache and network capacity must be available at the same time as computing capacity, etc. Every aspect of such a system is dynamic: locating and scheduling resources, adapting running application systems to availability and congestion in the middleware and infrastructure, responding to human interaction, etc. The technologies, the middleware services, and the architectures that are used to build useful high-speed, wide area distributed systems, constitute the field of data intensive computing. This paper explores some of the history and future directions of that field.

International Nuclear Information System (INIS)

Object: To smoothly control automatic water supply for realizing stable operation of a nuclear reactor by providing a flow rate limiting signal selection circuit and a preferential circuit in a water supply control device for a nuclear reactor wherein the speed of a recirculation pump may be changed in two-steps. Structure: Opening angle signals for a water supply regulating valve are controlled by a nuclear reactor water level signal, a vapor flow rate signal and a supplied water flow rate signal through an adder and an adjuster in response to a predetermined water level setting signal. When the water in the reactor is maintained at a predetermined level, a selection circuit receives a water pump condition signal for selecting one of the signals from a supplied water rate limiting signal generator generating signals for indicating whether one or two water supply pumps are operated. A low value preferential circuit passes the lower of the values generated from the ...

International Nuclear Information System (INIS)

The effect of electron beam welding parameters on fusion zone (FZ) microstructure and porosity in a Ti-6.8 Al-3.42 Mo-1.9 Zr-0.21 Si alloy (Russian designation VT 9) has been investigated. It has been observed that the FZ grain width increased continuously with increase in heat input when the base metal was in the #beta# heat-treated condition, while in the #alpha# + #beta# heat-treated base metal welds, the FZ grain width increased only after a threshold energy input. The difference is attributed to both the weld thermal cycle and the pinning effect of equiaxed primary alpha on grain growth in the heat-affected zone (HAZ) of #alpha# + #beta# heat-treated base metal. Postweld heat treatment (PWHT) in the subtransus and supertransus regions did not alter the columnar grain morphology in the FZ, possibly due to the lack of enough driving force for the formation of new grains by the breaking up of the columnar grains and grain boundary movement for grain growth. The highest porosity was ...

International Nuclear Information System (INIS)

Within the framework of the EU power plant conceptual study (PPCS), a modular He-cooled divertor concept with integrated pin array (HEMP) is being developed at the Forschungszentrum Karlsruhe. The design goal is to achieve a high heat flux of at least about 10-15 MW/m"2, which is proposed for a near-term reactor model like DEMO. The development and optimization of the divertor concept require a close link between the main issues: design, analyses, materials and fabrication technology, and experiments with feedbacks between them to be accounted for. Design-specific requirements on materials and fabrication issues will be discussed.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a turbocharger for a two-cycle engine having an oil mist containing crankcase and burning a mixture of liquid fuel containing lubricating oil therein wherein the turbocharger comprises a shaft mounted in a housing for rotation by an exhaust-driven turbine on one end to a drive compressor on the other end connected to supply pressurized air for the fuel/air mixture of the engine, the improvement to supply lubrication to the shaft and automatically enrichen the fuel/air mixture during high speed turbocharging.

Energy Technology Data Exchange (ETDEWEB)

Horizontal vibrations of elevator cars mainly occur because a car swings as roller guides installed at corners of a car frame move on a winding guide rail at high speeds. Rider comfort in high speed elevators is worsened by these vibrations. Conventional active dampers suppressing horizontal vibrations using ac servo motors make cars heavier so driving power becomes larger, and they are not easily applied to existing elevators. An active damping control method suited to super-high-speed elevators is which can solve these problems. The method suppresses vibrations by generating only enough magnetic force needed to suppress them only when vibrations of the car franc are produced. The vibrations are detected using acceleration detectors and magnets installed on left and right sides of the car frame. A computer simulator was made to analyze phenomena of car vibrations and to verify ...

British Library Electronic Table of Contents (United Kingdom)

An eddy current probe of the level of molten metal is considered for a sectional machine of continuous casting of steel. The advantages of electromagnetic probes of the level over radiometric ones lie in their insensitivity to the layer of dross and high speed. The results and directions of further studies are given.

Science.gov (United States)

Heterogeneous gasless reactive systems, including high-energy density metal-nonmetal compositions, have seen increasing study due to their various applications. However, owing to their high reaction temperature, short reaction time, and small scale of heterogeneity, investigation of their reaction mechanisms and kinetics is very difficult. In this study, microstructural changes and the kinetics of product layer growth in the W-Si system was investigated using a high-speed x-ray phase-contrast imaging technique. Using the Advanced Photon Source of Argonne National Laboratory, this method allowed direct imaging of irreversible reactions in the W-Si reactive system at frame rates up to 36 000 frames per second with 4 {mu}s exposure and spatial resolution of 10 {mu}m. Details of the Si melt and reactions between W and Si, that are unable to be viewed with visible-light imaging, were revealed. These include processes such as the ...

Energy Technology Data Exchange (ETDEWEB)

In the GE 7FDL single cylinder research diesel engine, in-cylinder high-speed photographic studies were conducted on coal-water slurry (CWS) fuel combustion. Distinct flames of pilot and CWS combustion were noticed. It was proven that the coal fuel burns after piston impingement and secondary atomization. Agglomerated particles will develop when combustion conditions are not favorable. Cylinder pressure data were simultaneously recorded for each film frame. Heat release data can thus be produced for each photo study. Most of the findings of earlier combustion studies on engine performance were confirmed.

Energy Technology Data Exchange (ETDEWEB)

A 46.3-ft-dia 20-degree conical ribbon parachute has been designed to retard a 2200-lb payload delivered at speeds up to 800 KCAS and at altitudes as low as 150 feet above ground level. The parachute uses both Kevlar and nylon materials, some of which were developed specifically for this parachute. The canopy design incorporates a patented construction geometry to minimize stress concentrations. A cluster of three 3.8-ft-dia ribbon parachutes is used to deploy the main parachute in the presence of severe aircraft flow field effects and large payload angles of attack. The results of over 30 full-scale flight tests indicate that fundamental limitations imposed by the dynamics of the air masses inside and behind the canopy determine the ultimate performance of a single large parachute when it is used at a release altitude of 150 ft.

International Nuclear Information System (INIS)

Electrical properties of 16 keV, focused-ion-beam (FIB) (beam diameter: 1 #mu#m, current density: 50 mA/cm"2) boron-implanted silicon layers have been investigated as a function of beam scan speed and ion dose, and compared with those obtained by conventional implantation (current density: 0.4 #mu#A/cm"2). High electrical activation of the FIB implanted layers is obtained by annealing below 800"0C as a result of the increase in amorphous zones created in the implanted layers. Amorphous zone overlapping is assumed to occur at FIB implantation doses of 3 - 4 x 10"1"5 ions/cm"2 from the results of electrical activation and the carrier profile of implanted regions annealed at low temperature, if beam scan speed is lowered to about 10"-"2 cm/s. (author).

Energy Technology Data Exchange (ETDEWEB)

Unmanned Aerial Vehicles (UAV) are being proposed for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration airplane. Due to the weight, speed, and altitude constraints imposed on such aircraft, solar array generated electric power is a viable alternative to air-breathing engines. Development of such aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) is currently building a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office. Expected completion of the plane is early 1995, with the airplane currently undergoing flight testing using battery power.

Energy Technology Data Exchange (ETDEWEB)

The unit cost of energy production of wind generators is examined by means of a model of the turbine power curve and the Weibull model of wind probability function, by applying the usual economic equations. The analysis is carried out in terms of dimensionless variables whose range of variability is defined by examining the data of 80 modern commercial wind turbines; likewise, the economic parameters are based on the present state of costs. The unit cost decreases asymptotically when alpha (ratio between mean wind speed and cut-in speed) - increases and shows a lower limit of 2 to 5 Ecent/kWh. This cost depends both on the value of the machine parameter {phi} (ratio between nominal and cut-in speed) and on the basic prices. The effect of the Weibull shape parameter kappa is different according to the values of {alpha} and {phi}: with low {alpha} and high {phi} the unit cost increases along with {kappa} ...

International Nuclear Information System (INIS)

local peanut cultivars Giza 4 and Giza 5 were exposed to different doses ( 50,100,150,200,250 and 300 Gy)to Co "6"0 gamma ray source . all irradiated materials were cultivated to give the M_1 and M_2 generation , then high yielding mutants were selected from the M_2 generation and cultivated separately to give the M_3 generation. some yield component traits were measured for the three generations (M_1,M_2 and M_3) and M_3 families.variations observed in these traits were attributed to genetic factors. the M_3 selected mutants were artificially infected by aspergillus flavus L spores (aflatoxins-B1 and B2 groups-producer strain). aflatoxin concentrations were estimated and the analysis showed that aflatoxin concentrations in seeds of the M_3 selected mutants from cultivar Giza 4 were higher than those in seeds of the M3 mutants selected from ...

British Library Electronic Table of Contents (United Kingdom)

We tested the hypothesis that overstorey of eucalypt forest dominated by tall, large diameter trees uses less water than regrowth stands in the high rainfall zone (>1100mmyear^-^1) of the northern jarrah (Eucalyptus marginata) forest in southwestern Australia. We measured leaf area, cover, sapwood area and sapwood density at three paired old and regrowth stands. We also measured sapflow velocity at one paired stand (Dwellingup) from June 2007 to October 2008. Old stands had more basal area but less foliage cover, less leaf area and slightly thinner sapwood. The ratio of sapwood area to basal area decreased markedly as tree size increased. Sapwood area of the regrowth forest stands (6.6+/-0.30m^2ha^-^1) was nearly double that of the old stands (3.4+/-0.17m^2ha^-^1), despite larger basal are...

International Nuclear Information System (INIS)

The next-to-leading-order (NLO) cross section for the production of heavy quarks at large transverse momenta #gamma##gamma# collision is calculated with perturbative fragmentation functions (PFF). This approach allows for a resummation of terms #propor to# #alpha#_sln(p"2/m"2) which arise in NLO from collinear emission of gluons by a heavy quark at large p or from almost collinear branching of photons or gluons into heavy-quark pairs. It is presented single-inclusive distributions in p and rapidity including direct and resolved photons for #gamma##gamma# production of heavy quarks at e"+e"-colliders and at high-energy #gamma##gamma# colliders. The results are compared with fixed- order calculation for m finite including QDC radiative corrections. The two approaches differ in the definitions and relative contributions of the direct and resolved terms, but essentially agree in their sum. The resummation of the ...

International Nuclear Information System (INIS)

Effect of strain and temperature on high temperature deformation properties of an alpha + beta titanium alloy Ti-6Al-4V has been investigated in the temperature range 800 to 910 deg. C by using the method of cross head speed cycling. On the basis of flow stress strain rate-strain rate sensitivity data and microstructural studies of the undeformed and deformed regions of tensile test pieces, both strain introduced hardening and softening effects were observed during the course of deformation which could be associated with grain coarsening and refining respectively. (author)

British Library Electronic Table of Contents (United Kingdom)

Abstract A fabrication process for Emitter-Wrap-Through solar cells on monocrystalline material with high quality gap passivation by wet thermal silicon dioxide is investigated. Masking and structuring steps are performed by screen-printing technology. Via-holes are created by an industrially applicable high-speed laser drilling process. The cell structure features a selective emitter structure fabricated in a single high temperature step: a highly doped emitter at the via-holes and the rear side, allowing for a low via-hole resistivity as well as a low resistivity contact to screen-printed pastes, and a moderately doped front side emitter exhibiting high quantum efficiency in the low wavelength range. Therefore a novel approach is applied depositing either doped or undoped PECVD silicon d...

International Nuclear Information System (INIS)

The effect of W and V on the high temperature strength properties of 12%Cr-15%Mn austenitic steels was studied from the view point of precipitation hardening and internal stress. The contribution of W addition to the tensile and creep-rupture strength was not so large. By contrast the combined addition of W and V increased the strength considerably. These are resulted from the precipitation of fine vanadium nitride (VN) within grains and the enhancement of M_2_3C_6 type carbide precipitation at grain boundaries. The V added material had large internal stress value which is considered to be due to dislocation movement disturbed by fine vanadium nitrides. (author).

British Library Electronic Table of Contents (United Kingdom)

Forest restoration efforts should aim at creating landscapes with a balanced array of forest stands at varying successional stages, thus providing habitat for a wealth of species and multiple ecosystem services. In most high-mountain ecosystems of South America, long-term livestock rearing activities that include fires, browsing, and trampling have delayed or stopped forest succession resulting in simplified landscapes. To determine appropriate restoration goals for Polylepis australis mountain forests of Central Argentina, we established 146 plots of 900 m2 plots throughout five river basins with different historic livestock stocking rates. In each plot, we measured tree heights, canopy cover, estimated age of oldest tree, volume of standing and fallen dead wood, fern cover, and abundance...

Science.gov (United States)

A newly developed 220 Mbps free-space 4-ary pulse position modulation (PPM) direct detection optical communication system is described. High speed GaAs integrated circuits were used to construct the PPM encoder and receiver electronic circuits. Both PPM slot and word timing recovery were provided in the PPM receiver. The optical transmitter consisted of an AlGaAs laser diode (Mitsubishi ML5702A, lambda=821nm) and a high speed driver unit. The photodetector consisted of a silicon avalanche photodiode (APD) (RCA30902S) preceded by an optical interference filter (delta lambda=10nm). Preliminary tests showed that the self-synchronized PPM receiver could achieve a receiver bit error rate of less than 10(exp -6) at 25 nW average received optical signal power or 360 photons per transmitted information bit. The relatively poor receiver sensitivity was believed to be caused by the insufficient electronic ...

Science.gov (United States)

Magnetic particles have become very promising materials for drug delivery. However, preparation of magnetite particles with high surface area, biocompatibility, strong magnetic response, and suitable particle size still remains a major challenge. In this report, magnetite nanocrystal clusters with high surface areas were fabricated through a solvothermal process by introducing ammonium acetate as a porogen and trisodium citrate as a surface modification agent. The porosity, which was controlled by the reactant concentration, has been investigated in detail. The surface area of the nanocrystal clusters was as high as 141?m(2) g(-1) . Ibuprofen, as a model drug, was entrapped into the magnetite carriers. The interfacial interaction between the carboxylic groups on the drug molecules and the carboxylate groups on the carriers enhanced the loading efficiency. Low cytotoxicity in MCF-7 ...

International Nuclear Information System (INIS)

Background and purpose: We evaluate the feasibility of concomitant and adjuvant docetaxel combined with three-dimensional conformal radiotherapy (3D-CRT) and androgen deprivation in high-risk prostate carcinomas. Methods: Fifty men with high-risk localized prostate cancer (16), locally advanced (28) or very high-risk prostate cancer (6) were included. Seventy Gy were delivered on prostate and seminal vesicles in 35 fractions, concurrently with weekly docetaxel (20 mg/m"2). Three weeks after the completion of 3D-CRT, docetaxel was given for 3 cycles (60 mg/m"2), every 3 weeks. Patients had to receive LHRH agonist during 3 years. Results: The intent to treat analysis shows that four patients out of 15 stopped prematurely the chemotherapy due to grade 3-4 acute toxicity. In the per protocol analysis, 46 patients completed a full-dose ...

Energy Technology Data Exchange (ETDEWEB)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed Tomography (X-CT) system are used to determine the flow regime, the instantaneous cross-sectional averaged void fraction, and the time averaged void fraction in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements are obtained for gas flow rates form 0.0 to 30.0 l/min. The flow regimes observed by all three measurement systems via image analysis shows that the results agree well with each other. Both the RTNR and the X-CT systems show that the time averaged and cross-sectional averaged void fraction increases with increasing superficial gas velocity. Time and cross-sectional averaged void fractions determined by the RTNR system agree within 4% with those determined by the high speed X-ray CT technique. ...

Energy Technology Data Exchange (ETDEWEB)

The development of turbine components for the automotive 100 kW ceramic gas turbine has entered the final stage of the seven-year project and is making satisfactory progress, toward the goals. The authors attained the interim targets of the aerodynamic performances and have been carrying out tests to further improve efficiency. As for ceramic parts, they have changed the material of the turbine rotor to a new one that is excellent in long-sustained and high-temperature strength properties, and have confirmed substantial strength at high temperature through hot-spin tests. After evaluating blade-vibration stress through analyses and experiments, the authors completed an endurance evaluation at 1200 C (1473 K) TIT (Turbine Inlet Gas Temperature) and a rated speed of 100,000 rpm. The authors are now carrying out endurance tests at 1350 C (1623 K) TIT. For ceramic stationary parts, they already finished the evaluations at 1200 ...

Science.gov (United States)

The macroscopic rotation of plasma in a toroidal containment device is an important feature of the equilibrium. Toroidal and polidal rotation in the high-beta tokamak Torus II is measured experimentally by examining the Doppler shift of the 4685.75 A He II line emitted from the plasma. The toroidal flow at an average velocity of 1.6 x 10/sup 6/ cm/sec, a small fraction of the ion thermal speed, moves in the same direction as the toroidal-plasma current. The poloidal flow follows the ion diamagnetic current direction, also at an average speed of 1.6 x 10/sup 6/ cm/sec. In view of certain ordering parameters, the toroidal flow is compared with predictions from neoclassical theory in the collisional, Pfirsch-Schluter regime. The poloidal motion, however, results from an E x B drift in a positive radial electric field, approaching a stable ambipolar state. This radial electric field is determined from theory by using the ...

Energy Technology Data Exchange (ETDEWEB)

Under severe operating conditions, such as starved lubrication, performance, service life, and reliability of rolling element bearings depend on the chemical and physical interactions between the contacting surfaces, the lubricant components, and the atmosphere. The IMKT{sup 1}, PI{sup 2}, and the imt{sup 3} have been cooperating on systematic investigations of interfacial interactions in high speed grease lubricated ball bearings. These include long time tests with complete bearings lubricated with greases of different composition under defined operating conditions, conducted at the IMKT, and chemical and physical characterizations of the running surfaces at the PI and imt. At the PI, in particular the chemical nature of the boundary layers has been investigated with time of flight secondary ion mass spectrometry (TOF-SIMS). The imt has been involved in the investigations by measuring the physical/mechanical properties of interacting surfaces ...

International Nuclear Information System (INIS)

A technique was developed that permits fluid flow to be visualized even where the flow is completely shrouded by metal. The technique employs real-time neutron radiography, which is similar to x-ray radiography except a collimated beam of neutrons is used. Various combinations of neutron-opaque tracer materials were tested with neutron-transparent fluid. Neutron opaque tracers, such as solid particles, fluid droplets, and streaklines were imaged through metal walls as they convected in neutron-transparent ambient fluid. Visualization of bubbles/voids were evaluated for possible future applications. Surface-flow patterns were also imaged by using neutron-opaque tufts. These techniques were evaluated for image contrast, resolution, and the ability to accurately track fluid flow fields. The techniques were also modeled to optimize contrast in various flow configurations. Imaging techniques such as real-time video, high speed video, and ...

CERN Document Server

One of the most interesting discoveries of the X-ray Telescope and EUV Imaging Spectrometer (EIS) on board the Hinode solar observatory is the presence of persistent high temperature high speed outflows from the edges of active regions. Measurements by EIS indicate that the outflows reach velocities of 50 km/s with spectral line asymmetries approaching 200 km/s. It has been suggested that these outflows may lie on open field lines that connect to the heliosphere, and that they could potentially be a significant source of the slow speed solar wind. A direct link has been difficult to establish, however. In this letter, we use EIS measurements of spectral line intensities that are sensitive to changes in the relative abundance of Si and S as a result of the first ionization potential (FIP) effect, to measure the chemical composition in the outflow regions of AR 10978 over a period of 5 days in December ...

Energy Technology Data Exchange (ETDEWEB)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

Energy Technology Data Exchange (ETDEWEB)

The piston bowl design is one of the most important factors that affect the air-fuel mixing and the subsequent combustion and pollutant formation processes in a direct-injection diesel engine. The bowl geometry and dimensions, such as the pip region, bowl lip area, and toroidal radius, are all known to have an effect on the in-cylinder mixing and combustion process. In order to understand better the effect of re-entrant geometry, three piston bowls with different toroidal radii and lip shapes were investigated using computational fluid dynamics engine modelling. KIVA3V with improved submodels was used to model the in-cylinder flows and combustion process, and it was validated on a high-speed direct-injection engine with a second-generation common-rail fuel injection system. The engine's performance, in-cylinder flow, and combustion, and emission characteristics were analysed at maximum power and maximum torque conditions and at part-load operating ...

International Nuclear Information System (INIS)

Sesame varieties/genotypes showed a good response to radiation with gamma rays and treatments with EMS. In M_1 both gamma rays and EMS influenced germination, seedling height, survival of plants and pollen fertility/sterility, producing deleterious effects on these characters. Compared to black seeded genotypes, white seeded ones are more susceptible to radiation. Both gamma rays and EMS produced various types of morphological variations in M_2 generation. These were dwarf plant mutants, mottled and fleshy leaved mutants (sterile), fasciated stem, flower colour, altered phyllotaxy, early, uniculm, capsule size variations, multiple capsule/leaf axil, seed coat colour variations, indehiscent and semi-indehiscent type mutants. Moreover, studies on quantitative characters including seed yield revealed the induction of mutants in both positive and negative directions for such traits which made a good scope of selection of desirable mutants in ...

British Library Electronic Table of Contents (United Kingdom)

A study was conducted to determine the fitting soil moisture for the normal growth of two-year-old W. sinensis (Sims) Sweets by using gas exchange technique. Remarkable threshold values of net photosynthetic rate (Pn), transpiration rate (Tr) and water use efficiency (WUE) were observed in the W. sinensis leaves treated by various soil moisture and photosynthetic available radiation (PAR). The fitting soil moisture for maintaining a high level of Pn and WUE was in range of 15.3%?26.5% of volumetric water content (VWC), of which the optimal VWC was 23.3%. Under the condition of fitting soil moisture, the light saturation point of leaves occurred at above 800?mol?m?2?s?1, whereas under the condition of water deficiency (VWC, 11.9% and 8.2%) or oversaturation (VWC, 26.5%), the light saturatio...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

In recent years, Obesity (defined as Body Mass Index > 30 kg/m2) has increased its prevalence reaching epidemic levels in countries such as The United States where it has became a national health issue. In Colombia the Obesity prevalence is figured around 14%. Treatment options for Obesity include life style modifications, pharmacologist management and surgical approach (Bariatric Surgery). This article describes a patient with previous bariatric surgery, who presents abdominal pain and melena owed to isquemic process of the alimentary limb caused by an internal hernia which is a potentially lethal condition if it is not highly suspected allowing its early diagnosis and treatment

Energy Technology Data Exchange (ETDEWEB)

Hydrogen piston engines can be simultaneously optimized for improved thermal efficiency and for extremely low emissions. Using these engines in constant-speed, constant-load systems such as series hybrid-electric automobiles or home cogeneration systems can result in significantly improved energy efficiency. For the same electrical energy produced, the emissions from such engines can be comparable to those from natural gas-fired steam power plants. These hydrogen-fueled high-efficiency, low-emission (HELE) engines are a mechanical equivalent of hydrogen fuel cells. HELE engines could facilitate the transition to a hydrogen fuel cell economy using near-term technology.

Energy Technology Data Exchange (ETDEWEB)

The ongoing upgrade of the Los Alamos Free-Electron Laser (FEL) Facility involves the addition of a photoelectric injector (PEI) and acceleration capability to about 40 MeV. The electron-beam and high-speed diagnostics provide key measurements of charge, beam position and profile, divergence emittance, energy (centroid, spread, slew, and extraction efficiency), micropulse duration, and phase stability. Preliminary results on the facility include optical transition radiation interferometer measurements of divergence (1 to 2 mrad), FEL extraction efficiency (0.6 {plus minus} 0.2%), and drive laser phase stability (< 2 ps (rms)). 10 refs.

Energy Technology Data Exchange (ETDEWEB)

The title invention aims at a vibrations-free running of the flywheel to realize a high speed (18,000-20,000 revolutions per minute). The flywheel consists of a case which holds a central stator, a rotor and two ball-bearings. The ball-bearings have a first radial stiffness and are placed in between the rotor and an upper, respectively lower support bearer. The support bearers are supported on the stator with a second radial stiffness. The top and the bottom of the stator is connected to the case by means of a support with a third stiffness. 6 figs.

Energy Technology Data Exchange (ETDEWEB)

The increasing sophistication of modern cars and todays tendency of developing compact vehicles more adapted to urban traffic have led to increased performance requirements from alternators and their bearings. This paper describes todays criteria for the design of alternators and of their bearings (improvement of tightness, design of race, grease, specific steels) and the final validation of the products. The last part of the paper describes the new CARB toroidal roller bearing developed by SKF which can support misalignments and internal axial displacements under high rotation speeds. (J.S.)

International Nuclear Information System (INIS)

An imaging position sensitive detector for charged particles, neutrons, X-and gamma rays has been developed. The novel feature of this scintillation imaging radiation detector is its ability to detect individual nuclear particle scintillations with a h igh degree of spatial resolution. The key elements of this detector system are a high gain, low noise image intensifier tube, a CCD camera and commercially available image processing hardware and software. This detector system is highly effective for applications such as low fluence and real time neutron radiography, mapping of radioactive contamination in nuclear reactor fuel rods, X-ray diffraction imaging, high speed autoradiography and in general position sensitive detection of nuclear radiation. Results of some of the exploratory experiments carried out using this detector system are presented in this paper. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Abstract The brain is highly sensitive to environmental hypoxia. Little is known, however, about the neuropsychological effects of high altitude residence in the developing brain. We recently described only minor changes in processing speed in native Bolivian children and adolescents living at approximately 3700-m. However, evidence for loss of cerebral autoregulation above this altitude (4000-m) suggests a potential threshold of hypoxia severity over which neuropsychological functioning may be compromised. We conducted physiological and neuropsychological assessments in 62 Bolivian children and adolescents living at La Paz (-3700-m) and El Alto (-4100-m) in order to address this issue. Groups were equivalent in terms of age, gender, social class, schooling, parental education and genetic ...

International Nuclear Information System (INIS)

Nanoporous materials have become indispensable in many fields ranging from photonics, catalysis and semiconductor processing to biosensor infrastructure. Rapid and energy efficient process fabrication of these materials is, however, nontrivial. In this communication, we describe a simple method for the rapid fabrication of these materials from colloidal dispersions of Polymethyl Silsesquioxane nanoparticles. Nanoparticle-polymer composites above the decomposition temperature of the polymer are examined and the entropic gain experienced by the nanoparticles in this rubric is harnessed to fabricate novel highly porous films composed of nanoparticles. Optically smooth, hydrophobic films with low refractive indices (as low as 1.048) and high surface areas (as high as 1325 m2 g-1) have been achieved with this approach. In this communication we address the behavior of such systems that ...

Energy Technology Data Exchange (ETDEWEB)

The main purposes of this research was to investigate the feasibility of incineration of wool-scouring sludge in a novel vertical-axis-rotating fluidised bed (RFB). The experiment was carried out in a RFB with an internal diameter (ID) of 200 mm and height of 50 mm. A cold test was first conducted to investigate the fluidization performance of the RFB via parameters such as the bubbling, gas distribution, bed shape and pressure drop. The tumbling phenomena was observed in the bed, and this effectively enhanced the axial mixing. The appropriate range of bed thickness, rotating speed and sand particle size were identified to ensure the full fluidization and reduce the particle elutriation. Four wool-scouring sludges from different processes were incinerated in the RFB. With 5% support methane, all sludges with a maximum moisture up to 70% as received could be successfully burned in the RFB at rotating speeds of 200 and 300 rpm. The combustion was ...

International Nuclear Information System (INIS)

Heat transfer augmentation in narrow rectangular channels in a target system is a very important method to remove high heat flux up to 12 MW/m"2 generated at target plates of a high-intensity proton accelerator of 1.5 GeV and 1 mA with a proton beam power of 1.5 MW. In this report, heat transfer coefficients and friction factors in narrow rectangular channels with one-sided rib-roughened surface were evaluated for fully developed flows in the range of the Reynolds number from 6,000 to 1,00,000; the rib pitch-to-height ratios (p/k) were 10,20 and 30; the rib height-to-equivalent diameter ratios (k/De) were 0.025, 0.03 and 0.1 by means of previous existing experimental correlations. The rib-roughened surface augmented heat transfer coefficients approximately 4 times higher than the smooth surface at Re=10,000, p/k=10 and k/De=0.1; friction factors increase around 22 times higher. In this case, higher heat ...

Science.gov (United States)

... 24 1.6. Storm Movement .. .. . ... W hydrometeor fall speed containing the vertical velocity and the particle terminal fall speed (= w + V) ...

International Nuclear Information System (INIS)

Tensile properties of reduced-activation 10Cr-30Mn austenitic steels with carbon levels from 0.003 to 0.55% were investigated over the temperature range from room temperature to 873 K after neutron irradiation in the Japan Materials Testing Reactor at 573 K to 8.5x10"2"2 n/m"2. Irradiation-induced increase in yield stress increased significantly with carbon concentration up to about 0.1% and it was constant above 0.1% carbon. A high density of dislocation loops with small (below 10 nm) and large (20-30 nm) sizes formed during irradiation. The high density, small loops caused a large irradiation hardening, while the large loops contributed only slightly to irradiation hardening. It was considered that carbon atoms formed the small loops together with irradiation defects. The deformation channeling was observed in the irradiated high carbon steels, 0.11 and 0.55% carbon, but not in ...

Energy Technology Data Exchange (ETDEWEB)

In the research of a more efficient, less costly, more environmentally responsible and less technically difficult method for generating electrical power from coal, `the Partially Gasified Coal Fired Combined Cycle with a CFBC with Different Speeds (DFBC)` is introduced by Tsinghua University. The high efficiency cycle includes gasification, compressed air heating in a fluidized bed immersed air heater followed by a combustor and the heat recovery of gas turbine exhausted gas used as the combustion of coal in the differential-velocity atmospheric circulating fluidized bed. Superheated steam is raised in the DFBC boiler. A preliminary analysis is made for the choice of combined cycle components. The computer program can be used to evaluate the design and off-design performance of the power plant. The simulation results show that the new system is a valuable coal fired combined cycle system for China, mainly to the improvement of the existing ...

Energy Technology Data Exchange (ETDEWEB)

Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ...

International Nuclear Information System (INIS)

This paper reports on an experimental investigation of premixed methane/air combustion stabilized within a reticulated partially stabilized zirconia foam burner that was performed. A flame holder was used to extend the stability range to allow a stable flame to be maintained for a variety of flow rate and equivalence ratio combinations. The stability range, temperature distributions, and emissions were examined over a range of equivalence ratios and flow rates. The flame was found to be axisymmetric for all conditions in which the reactants were sufficiently well mixed and the flow distribution was sufficiently uniform. Burning speeds were measured that were well in excess of the laminar flame speed. The axial temperature distribution (measured around the burner annulus) in the postflame zone was found to be relatively insensitive to flow rate but dependent upon the burner core length. Very low concentrations of NO_x were found for fuel/air ...

International Nuclear Information System (INIS)

This paper shows the efficacy of computed radiography for major airway in pediatrics. For this purpose, we examined 40 children (range 2 weeks to 14 years; mean 2.3 years) using Fuji Computed Radiography (FCR) and radiation dose using pediatric phantom under FCR and conventional film and screen system. In comparison study with FCR and conventional film and screen system, FCR images are superior to conventional system in all cases. Scorings were done for the quality of the image of the pharynx, the trachea, and both main bronchi. In phantom study to check radiation dose, radiation dose could be reduced 1/6 of the value using high speed film and screen and 1/15 of the value using conventional speed film and screen. FCR also showed clear airway images in all cases but technical failure to evaluate the clinical lesion. These results suggest that FCR is the adequate imaging modality to evaluate the major airway in children. ...

International Nuclear Information System (INIS)

Environmental factors, phytoplankton biomass (Chl a) and primary production of two water areas in Daya Bay (Dapeng'ao Bay and Aotou Bay) were investigated during the transition period from spring to summer. Chl a ranged from 3.20 to 13.62 and 13.43 to 26.49 mg m"-"3 in Dapeng'ao Bay and Aotou Bay respectively, if data obtained during red tides are excluded. Primary production varied between 239.7 and 1001.4 mgC m"-"2 d"-"1 in Dapeng'ao Bay. The regional distribution of Chl a and primary production were mostly consistent from spring to summer in both bays. Seasonal transition characters have been found in Daya Bay from spring to summer, including high values of DO, nitrate and silicate. Size structures of phytoplankton and its primary production do not change very much from spring to summer, with micro-phytoplankton dominating and contributing about 50% of the whole. In Daya Bay, phytoplankton is limited by nitrogen in ...

Energy Technology Data Exchange (ETDEWEB)

Direct injection diesel engines power most of the heavy-duty vehicles. Due to their superior fuel economy, high power density and low carbon dioxide emissions, turbocharged, small bore, high speed, direct injection diesel engines are being considered to power light duty vehicles. Such vehicles have to meet stringent emission standards. However, it is difficult to meet these standards by modifying the in-cylinder thermodynamic and combustion processes to reduce engine-out emissions. After-treatment devices will be needed to achieve even lower emission targets required in the production engines to account for the anticipated deterioration after long periods of operation in the field. To reduce the size, mass and cost of the after-treatment devices, there is a need to reduce engine-out emissions and optimize both the engine and the aftertreatment devices as one integrated system. For example, the trade-off between engine-out ...

International Nuclear Information System (INIS)

A novel sodium lead pentaborate, NaPbB5O9, has been successfully synthesized by standard solid-state reaction. The single-crystal X-ray structural analysis showed that NaPbB5O9 crystallizes in the monoclinic space group P21/c with a=6.5324(10) A, b=13.0234(2) A, c=8.5838(10) A, ?=104.971(10)o, and Z=4. The crystal structure is composed of double ring [B5O9]3- units, [PbO7] and [NaO7] polyhedra. [B5O9]3- groups connect with each other forming two-dimensional infinite ?[B5O9]3- layers, while [PbO7] and [NaO7] polyhedra are located between the layers. [PbO7] polyhedra linked together via corner-sharing O atom forming novel infinite ?[PbO6] chains along the c axis. The thermal behavior, IR spectrum and the optical diffuse reflectance spectrum of NaPbB5O9 were reported. -- Graphical abstract: A new phase, NaPbB5O9, has been discovered in the ternary M2O-PbO-B2O3 (M=alkali-metal) system. The crystal structure consists of a novel infinite ?[PbO6] ...

Energy Technology Data Exchange (ETDEWEB)

During the first phase of this project, significant progress was made in several of the connected issues that make up the objectives of this grant. The central thrust or theme of this work under the DOE/ERIP grant is to carry out prototype testing of the concept of tribopolymerization as a novel mechanism of boundary lubrication--under more severe, high-load, high-speed conditions that are most likely to exist in field applications. The authors see this as an important step in attracting industries to license and market the results of this new technology. In addition, they have began to explore other potential, energy-saving applications of the concept of tribopolymerization. These exploratory studies are quite promising; they are likely to open new doors in industrial applications. To carry out the experimental part of this program, a new device has been built. Highlights of these and other developments are given.

British Library Electronic Table of Contents (United Kingdom)

It has been considered that dry-out occurs easily in boiling heat transfer for a small channel, a mini- or microchannel, because the channel was easily filled with coalescing vapor bubbles. In the present study, the experiments of subcooled flow boiling of water were performed under atmospheric conditions for a horizontal rectangular channel for which the size is 1 mm height and 1 mm width, with a flat heating surface of 10 mm length and 1 mm width placed on the bottom of the channel. The heating surface has a top of copper heating block and is heated by ceramic heaters. In the high heat flux region of nucleate boiling, about 70-80% of the heating surface was covered with a large coalescing bubble and the boiling reached critical heat flux as observed by high-speed video. In the beginning ...

British Library Electronic Table of Contents (United Kingdom)

We have discovered a previously unidentified thermal explosion mode using the Los Alamos deflagration cylinder test (DFCT). The DFCT is a "pipe bomb"-style test similar to the detonation cylinder test (DTCT), which has been used for many years to calibrate detonation product equations of state. The shot is heated in an oven to a uniform test temperature. The pre-heated high explosive (HE) is triggered by a hot wire initiator on one end. The tube is back-illuminated by a bright light source, and its combustion-driven deformation and subsequent break-up are observed by a high-speed framing camera. Like the DTCT, the DFCT tube wall motion provides the primary diagnostic. A variety of reactive responses are possible, including quasi-steady deflagration and deflagration-to-detonation transition...

British Library Electronic Table of Contents (United Kingdom)

Culture-independent microbiological technologies that interrogate complex microbial populations without prior axenic culture, coupled with high-throughput DNA sequencing, have revolutionized the scale, speed and economics of microbial ecological studies. Their application to the medical realm has led to a highly productive merger of clinical, experimental and environmental microbiology. The functional roles played by members of the human microbiota are being actively explored through experimental manipulation of animal model systems and studies of human populations. In concert, these studies have appreciably expanded our understanding of the composition and dynamics of human-associated microbial communities (microbiota). Of note, several human diseases have been linked to alterations in th...

International Nuclear Information System (INIS)

High temperature deformation behavior of an alpha + beta titanium alloy Ti-3Al-2.5V has been investigated in the temperature range 830 deg. C to 910 deg. C by using the method of cross head speed cycling. On the basis of flow stress-strain rate and strain rate sensitivity data, it was found that the alloy exhibits a hardening effect in the entire temperature range studied, amount of hardening being significant at the highest test temperature of 910 deg. C which resulted in a degradation of superplastic properties of the alloy. Grain growth in beta-phase due to strain was considered responsible for the hardening effect observed.

British Library Electronic Table of Contents (United Kingdom)

Biostimulation by nutrient application is a viable technology for restoring oil-contaminated beaches. Maximizing the nutrient residence time is key for achieving a rapid cost-effective cleanup. We considered the nutrient injection strategy through a perforated pipe at the high tide line and we simulated numerically beach hydraulics, which allowed us to estimate the optimal injection flow rate of nutrient solution. Our results indicate that the optimal application is one that starts following the falling high tide and lasts for half tidal cycle. The saturated wet-front of the nutrient solution on the beach surface would move seaward with the same speed of the falling tide keeping a constant distance with the tide line. The numerical results were generalized to beaches of wide ranges of hydr...

Energy Technology Data Exchange (ETDEWEB)

In case of airplane engine, technical development like increase of temperature at the turbine entrance or high speed rotation with a purpose of thrust up, and reduction of structural part single substance mass or reduction of number of parts in order to achieve lightness and so forth, has been promoted in order to improve the performance that is evaluated by thrust weight ratio (thrust/weight). Accordingly, research and development of high heat resistance, high strength, lightness and so forth of each material of the parts are in demand. As a representative material corresponding to such demand, L10 type {nu}-TiAl intermetallic compound which is light and has improved high temperature strength properties is paid attention and its development is promotes. The authors were successful for the first time in the world to manufacture composite material with CVD type SiC fiber that was ...

CERN Document Server

We investigate strong nonlinear damping effects which occur during high amplitude oscillations of neutron stars, and the gravitational waves they produce. For this, we use a general relativistic nonlinear hydrodynamics code in conjunction with a fixed spacetime (Cowling approximation) and a polytropic equation of state (EOS). Gravitational waves are estimated using the quadrupole formula. Our main interest are $l=m=2$ $f$-modes subject to the CFS (Chandrasekhar, Friedman, Schutz) instability, but we also investigate axisymmetric and quasi-radial modes. We study various models to determine the influence of rotation rate and EOS. We find that axisymmetric oscillations at high amplitudes are predominantly damped by shock formation, while the non-axisymmetric $f$-modes are mainly damped by wave breaking and, for rapidly rotating models, coupling to non-axisymmetric inertial modes. From the observed ...

KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Two-year uninterrupted sodar measurements of vertical profiles of wind speed and direction in the height range 40 to 250-500 m were carried out in two points of Moscow megalopolis. Seasonal and diurnal courses of mean speed profiles, wind speed distributions, wind roses and occurrence of strong and weak wind speed events are shown. Influence of urban heat island and orography on wind field is discussed.

Science.gov (United States)

In our previous paper (Lanzafame et al. 2000, PASJ 52, 515) we showed, through 2D SPH simulations, that the stellar mass ratio, M 2 / M 1, of a close binary system (that determines the position and then the initial specific angular momentum at L 1) plays a fundamental role in the formation and development of spiral structures and shock fronts in the radial flow of accretion discs. In that work only a quasi-sonic value of the injection velocity at L 1 was considered. In the present work we also carried out 2D SPH simulations with the aim to investigate the development of such structures, while keeping constant the mass of the compact primary (M 1 = 1 M odot) and the separation between the two components, and assuming as an initial condition of two different supersonic injection velocities at L 1, characterizing two sets of simulations. For each set we considered four values of the secondary to primary mass ratio, M ...

International Nuclear Information System (INIS)

The creep characteristics of alloy 800 at temperatures around 600"0C are greatly affected by the composition and treatments in the final stages of manufacture. Short-term and creep properties of alloy 800 at 600"0C are described for six melts covering the carbon range 0.054-0.078%, the titanium range 0.23-0.57% and the aluminium range 0.17-0.52%. The properties are related to the alloy chemistry and the microstructure. It is shown that homogeneously nucleated #gamma#'-precipitates are the main cause of low ductility in alloy 800 but there is also some influence of, for instance, grain boundary M_2_3C_6 films and discontinuous precipitation of Ni_3Ti or M_2_3C_6 in grain boundaries. The extent of #gamma#'-precipitation is controlled primarily by the (Ti+Al)-content. To avoid #gamma#' and ensure a high creep ductility the (Ti+Al)-content should be limited to 0.70-0.75% for alloy 800 ...

Energy Technology Data Exchange (ETDEWEB)

The idle speed of an internal combustion engine is controlled in response to a variable ignition timing control signal from a microcomputer. The microcomputer derives this control signal as a function of the magnitude of engine speed variation which occurs during engine idle periods to cause the ignition timing to vary quickly in response to a transitory engine load variation. An auxiliary air delivery system may be advantageously incorporated in the idle speed control system to cooperate with the ignition timing control in response to the engine speed variation.

Energy Technology Data Exchange (ETDEWEB)

The present article describes the specialities in various chemical process equipment fabricated by Hitachi. It introduces the thin-film evaporator which heats, vaporizes and concentrates high viscosity fluid and slurry under thin-film conditions, the centrifugal extractor which uses a high speed rotating rotor to separate two kinds of immiscible liquids effectively in counter current contact conditions under a gravitational force ranging from 2,000G to 4,500G, the process gas boiler and heat pipe equipment which recovers exhausted heat effectively from various plants, the furnace and quench systems which are applied to olefin plants, EDC cracking and steam reforming, and the equipment which has been supplied to chemical plants operated under severe conditions, such as high temperature, high pressure and corrosive atmosphere. It was demonstrated that these technologies and know-hows ...

Energy Technology Data Exchange (ETDEWEB)

Diesel passenger car is superior to gasoline engine car in the fuel economy, but it has some defects to improve: noise, startability, particulate and transient performance, etc. Among these problems, this paper presents particularly transient performance in a diesel engine and clarifies the causes of its decline at lower temperature operation. As the results, it is found that the transient torque at the early stage of acceleration is only 50% at -20/sup 0/C, and that when coolant temperature went up to 20/sup 0/C, the transient torque approaches to that of the warmed up engine. The transient response become worse with retarding the injection timing and with decreasing the engine speed. On the other hand, since the normal response is not obtained despite using high cetane number fuel, main cause of the inferior transient torque is not the poor combustion, but the increase of friction or cooling loss.

International Nuclear Information System (INIS)

High-resolution observations are presented of the 300-kpc jet in the giant radio galaxy NGC 6251. The width of the jet is resolved over most of its length, and the axis of the jet wiggles with an amplitude increasing linearly with distance from the nucleus. Polarization data are used to derive densities of cold matter in the jet and, from the argument that the jet must form the lobe in a time equal to the age of the lobe, the speed of the jet is estimated as c/20. The energetics of the jet are then dominated by the bulk flow along it of cold matter at a rate of 1 solar mass yr"-"1. The jet appears to be confined; the wiggle of its axis is probably due to oscillations of the direction of the collimator with a period of about 6 x 10"6 yr. (author).

Energy Technology Data Exchange (ETDEWEB)

In this paper, research on pass schedule of tandem cold mill (TCM) is carried out. According to load (reduction, rolling force, motor power) balance, non-linear equations set with variables of inter-stand thickness is constructed. The pass schedule optimization is carried out by solving the non-linear equations set. As the traditional method, the Newton-Raphson method is used for solving the non-linear equations set. In this paper a new simple method is brought up. On basis of the monotone relations between thickness and load, the inter-stands thickness is adjusted dynamically. The solution of non-linear equations set can be converged by iterative calculation. This method can avoid the derivative calculation used by traditional method. So, this method is simple and calculation speed is high. It is suitable for on-line control. (author)

International Nuclear Information System (INIS)

A steadily increasing part of comminution is nowadays carried out by tube ball mills. Our investigations are a first step to a possible tuning of material distribution with mechanical stress characteristic of the grinding media charge, that is essential for a high efficiency of grinding. A BOND mill filled with porcelain balls as grinding media and labelled corundum (Au-198) as grinding material was used to measure the distribution of material over the cross-section. The evaluation was made by linear interpolation between all combinations of adjacent measuring points to calculate all coordinates with equal intensity for each selected level of activity. Two plottings showing the dependence of material distribution on the rotating speed are presented. (author).

International Nuclear Information System (INIS)

This article describes the laser Thomson scattering principle and the developed system on HL-2A device. The high power Q-switch Nd:YAG laser, with a wavelength of 1064 nm, can sufficiently satisfy the measurement requirement. The polycromator consisting of avalanche photo-diodes(APD) and narrow band interference filters, can effectively improve the measurement of scattering light. The electron temperature is deduced by error-weighted lookup table method, which improves the data- processing speed or efficiency. Finally, the experiment results of the one-point electron temperature during different discharges of plasma are presented. (authors)

Energy Technology Data Exchange (ETDEWEB)

Running torque of bearings, temperature rise of the lubricating oil and power loss of the testing system were compared with hybrid ceramic bearings set HIP-Si{sub 3}N{sub 4} balls and AISI-M 50 steel ball bearings under the 2 million dN value ({phi}20 x 100,000 rpm). Over 1.4 dN value, hybrid ceramic bearings showed superior performance than M 50 steel ball bearings. If the proper oil filling condition is chosen, hybrid ceramic bearings reduce bearing power loss to about 55% of AISI-M 50 steel ball bearings at 2 million dN value. (author)

British Library Electronic Table of Contents (United Kingdom)

In this work, a pre-cracked semi-circular shaped explosive simulant was loaded using a split Hopkinson pressure bar (SHPB). A high-speed camera was used to capture the deformation and fracture process of the specimen in situ. The digital images were processed using the digital image correlation (DIC) method. Next, full displacement and strain fields were obtained. The displacement vector field shows that the specimen fractured under tensile stress action. The strain field can be used to predict the crack propagation. Results show that the method of combined DIC and SHPB is effective to study the dynamic deformation and fracture behavior of explosive simulants. In addition, the specimen was loaded using a drop weight. The fracture toughness of the specimen was preliminary measured.

International Nuclear Information System (INIS)

Object: To minimize the range of the liquid level variation of the cooling system and reduce the time required for the liquid level control by sealing the gas of a cover gas respiration system which acts upon an evaporator and pump overflow column. Structure: In liquid level control by the cover gas pressure of a high-speed reactor secondary cooling system, upon occurrence of a sudden change in the rate of flow of the recirculated liquid, automatic check valves provided in an evaporator and pump overflow column cover gas respiration system are completely or substantially closed, while at the same time the recirculation cooling medium is sucked up and an automatic check valve provided in the overflow system is closed. (Kamimura, M.).

CERN Document Server

The finite element method and dimensional analysis have been applied in the present paper to study a hydraulic impact, which is utilized in a non-explosive rock breaking technology in mining industry. The impact process of a high speed piston on liquid water, previously introduced in a borehole drilled in rock, is numerically simulated. The research is focused on the influences of all the parameters involved in the technology on the largest principal stress in the rock, which is considered as one of the key factors to break the rock. Our detailed parametric investigation reveals that the variation of the isotropic rock material properties, especially its density, has no significant influence on the largest principal stress. The influences of the depth of the hole and the depth of the water column are also very small. On the other hand, increasing the initial kinetic energy of the piston can dramatically increase the largest principal stress and ...

Energy Technology Data Exchange (ETDEWEB)

Genetic mapping is approached using the techniques of high resolution fluorescence in situ hybridization (FISH). This technology and the results of its application are designed to rapidly generate whole genome as tool box of expressed sequence to speed the identification of human disease genes. The results of this study are intended to dovetail with and to link the results of existing technologies for creating backbone YAC and genetic maps. In the first eight months, this approach generated 60--80% of the expressed sequence map, the remainder expected to be derived through more long-term, labor-intensive, regional chromosomal gene searches or sequencing. The laboratory has made significant progress in the set-up phase, in mapping fetal and adult brain and other cDNAs, in testing a model system for directly linking genetic and physical maps using FISH with small fragments, in setting up a database, and in establishing the validity and throughput ...

British Library Electronic Table of Contents (United Kingdom)

Flame propagating through zirconium particle cloud in a small-scale vertical rectangle chamber was investigated experimentally. In the experiments, the zirconium quoted 99% purity was used and the diameter of particles was distributed 1?22 ?m. The zirconium dust was dispersed into the chamber by air flow and ignited by an electrode spark. A high-speed video camera was used to record the images of the propagating flame. Micro-thermocouples, schlieren optical system and microscopic lens were used to obtain temperature profiles and flame structure, respectively. Based on the experimental results, flame propagation characteristics and flame structure of zirconium particle cloud were analyzed. The propagation velocity of the flame is quite slow in the initial 14 ms and then accelerates to maxim...

British Library Electronic Table of Contents (United Kingdom)

An experimental investigation on the air/water counter-current two-phase flow in a horizontal rectangular channel connected to an inclined riser has been conducted. This test-section representing a model of the hot leg of a pressurized water reactor is mounted between two separators in a pressurized experimental vessel. The cross-section and length of the horizontal part of the test-section are (0.25mx0.05m) and 2.59m, respectively, whereas the inclination angle of the riser is 50degree. The flow was captured by a high-speed camera in the bended region of the hot leg, delivering a detailed view of the stratified interface as well as of dispersed structures like bubbles and droplets. Countercurrent flow limitation (CCFL), or the onset of flooding, was found by analyzing the water levels mea...

International Nuclear Information System (INIS)

High temperature proton conductor (HTPC) oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs) operating at intermediate temperatures (400-700 "0C). The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs. (topical review)

Energy Technology Data Exchange (ETDEWEB)

The analysis of transmission line faults is essential to the proper performance of the power system. It is required if protective relays are to take the appropriate action and in monitoring the performance of relays, circuit breakers, and other protective and control elements. The detection and classification of transmission line faults is a fundamental component of such fault analysis. Another application of fault analysis is in software packages for automated analysis of digital fault recorder (DFR) files. Recently, such a package, called DFR Assistant, was developed for substation applications. This program can be installed locally in a substation, in which case it is connected directly to the DFR via a high speed parallel link, or it can be installed at a central station, in which case it can be configured to automatically analyze events coming from all DFRs.

Energy Technology Data Exchange (ETDEWEB)

We have studied the vibrational properties of the filled tetrahedral semiconductor LiMgAs and its binary analog AlAs by using the plane-wave pseudopotential method within density functional theory. The calculated lattice constants for the studied compounds are in good agreement with previous theoretical and experimental results. The phonon dispersion curves and phonon density of states are calculated by using density functional perturbation theory. The sound speeds in different directions are quantitatively similar in LiMgAs and AlAs. The assignment of the zone center modes to the relative motion of the atoms shows that the lower optic modes are due to the Mg-As pair vibrations, while for the upper ones the Li-Mg pair dominates, which is attributed to the smaller Mg atom mass. The longitudinal interatomic force constant of Mg-As is about 66% higher than that of Li-As, showing the relatively high covalency of the former bond.

British Library Electronic Table of Contents (United Kingdom)

Immobilized eggshell with a polymer mixture of alginate and polyvinyl alcohol was applied as a biocomposite adsorbent (ESC) for the adsorption of C.I. Remazol Reactive Red 198 from aqueous solution. ESC was characterized using XRD, TGA, FTIR and SEM. The Red dye adsorption onto the ESC was investigated in a batch system with respect to initial dye concentration, pH, contact time, agitation speed, solution temperature and biocomposite dosage. The prepared biocomposite exhibits high efficiency for red dye adsorption and the equilibrium states could be achieved in 3h for the different studied initial dye concentrations. The equilibrium isotherm study indicated that sorption data were analyzed and fitted well by both Langmuir and Temkin models compared to Freundlich model. The maximum monolaye...

DEFF Research Database (Denmark)

This paper presents a new method to compensate the nonlinearities for matrix converter drives. The nonlinearities of matrix converter drives such as commutation delay, turn-on and turn-off time of the switching devices, and on-state switching device voltage drop is corrected by a new matrix converter model using the direction of current. The proposed method does not need any additional hardware or complicated software and it is easy to realize by applying the algorithm to the conventional vector control. The proposed compensation method is applied for high-performance induction motor drives using a 3-kW matrix converter system without a speed sensor. Experimental results show the proposed method provides good compensating characteristics.

Science.gov (United States)

This paper discusses a new control strategy for photovoltaic power generation systems with consideration of dynamic characteristics of the photovoltaic cells. The controller estimates internal currents of an equivalent circuit for the cells. This estimated, or the virtual current and the actual voltage of the cells are fed to a conventional Maximum-Power-Point-Tracking (MPPT) controller. Consequently, this MPPT controller still tracks the optimum point even though it is so designed that the seeking speed of the operating point is extremely high. This system may suit for applications, which are installed in rapidly changeable insolation and temperature-conditions e.g. automobiles, trains, and airplanes. The proposed method is verified by experiment with a combination of this estimating function and the modified Boehringer's MPPT algorithm.

Energy Technology Data Exchange (ETDEWEB)

When a plasma becomes contaminated by foreign particles, generically referred to as dust, the result is called a dusty plasma. At the present time there is a great deal of interest in dusty plasmas because of their roles in terrestrial and extra-terrestrial processes - semiconductor processing, high temperature fusion experiments, stellar formation and the rings of Saturn. This thesis is concerned with the role of dust in processing type plasmas. In the following experiments, artificial dust is introduced into a parallel electrode plasma chamber. Ions and electrons in the plasma charge the dust particles and they become suspended in the plasma due to the balancing of electric and gravitational forces. By illuminating the suspended dust with laser light and using an extremely high speed camera fitted with a macro lens to look at the scattered light, the dust particles are observed directly. Specially written computer ...

International Nuclear Information System (INIS)

Type 304 stainless steels (solution annealed material, cold worked material and fine grain material) were neutron irradiated to 3 x 10"2"5n/m"2 at 290degC and at 50degC. Each specimen was examined by SSRT test in high temperature water with 8 ppm dissolved oxygen and Ar gas environments. Results were as follows: (1) IASCC susceptibility of each material can be classified by 0.2% proof stress (PS) obtained from SSRT test in Ar gas: No IASCC susceptibility was observed in the PS range 850 MPa. (2) The uniform elongation (UE) in Ar gas environment decreased with increasing PS up to 800 MPa, and became about 0% in the PS range >800 MPa. (3) It was suggested that IASCC did not occur even if material had IASCC susceptibility, when under a condition that brittle fracture mechanism controls a specimen failure. (author)

International Nuclear Information System (INIS)

In the frame of the European Technology R and D program for ITER, and in the area of High Heat Flux plasma facing Components (HHFC), representative small-scale mock-ups were manufactured and tested to compare different concepts and joining technologies (i.e. active brazing, Hot Isostatic Pressing (HIPping), diffusion bonding, etc.). On the basis of the results obtained by thermal fatigue tests, the monoblock concept resulted to be the most promising one, particularly when the HIPping manufacturing technology is used. Within this program, ENEA manufactured tungsten monoblock mock-ups by using the HIPping technology. The mock-ups were tested with respect to thermal fatigue and, upon screening tests, the best performance obtained was 15 MW/m"2 for 200 cycles. One of these mock-ups was enclosed in the 'Paride' neutron irradiation campaign. This campaign has the scope of enlarging the available database on the performance ...

International Nuclear Information System (INIS)

The possibility of smoothening aspherical X-ray mirrors by irradiation of the surface with a low-energy ion beam is investigated. Nanofocusing being the primary application of these mirrors the ion beam conditions must be optimized to achieve a surface roughness of the order of 0.1-0.2 nm. To address this issue a first study was performed on silicon flat substrates etched using ion energies ranging from 400 to 1200 eV. A second study consisted of eroding the silicon surface while varying the ion grazing incidence angle between 10 deg. and 90 deg. for a fixed value of the ion energy. The surface topography of the samples was characterized at various scales using atomic force microscopy (probed area: 1-10 ?m2), interferential optical microscopy (probed area: 1 mm2) and X-ray scattering (probed area: 100 mm2). Finally, a study by AFM of the evolution of the surface finish level of a silicon mirror after ion erosion at various depth values up to 10 ...

Energy Technology Data Exchange (ETDEWEB)

When a highly collimated beam of particles is aimed along the atomic rows of an aligned single crystal, the averaging effect of high speed motion results, to the lowest order of approximation, in crystal electric fields which are transverse to the atomic rows. The enormous magnitude of the crystal transverse electric fields is unsurpassed by any other known earth-bound macroscopic sources. For example, the field strengths along the <100> axis of tungsten at 77 K approach 9{center dot}10{sup 13}V/m. Thus quantum electrodynamic (QED) processes in strong fields which are thought to occur only in the extra-terrestrial environment can now be investigated in the laboratory. Here we review the results of measurements performed at the SPS facility in CERN using highly collimated beams of electrons, positrons and photons in the 20-200 GeV range, and germanium crystals cooled to 77 K with thicknesses ...

CERN Document Server

Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on Lorentz invariance violation (LIV). Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. I review the current status of LIV searches using GRBs and AGN flare events, and discuss limitations of light-travel time analyses and prospects for future ...

International Nuclear Information System (INIS)

We have obtained radial velocities for 69 stars in the globular cluster M2 (NGC 7089). M2's rotation axis is, within sizeable uncertainties, perpendicular to the major axis determined by the flattening. The ratio of rotational to random kinetic energy agrees with that predicted from the ellipticity assuming an oblate figure and an isotropic velocity-dispersion tensor. We have fitted King-Michie models to determine M2's mass, the exponent of an assumed power-law mass function, and the anisotropy radius. The most significant sources of uncertainty in the modeling are the velocity dispersion, the distance, and the mass-luminosity relation for the cluster stars. The models favor mass functions similar to or shallower than the Salpeter initial-mass function and a moderate amount of velocity anisotropy.

Energy Technology Data Exchange (ETDEWEB)

Transmission line faults must be located accurately to allow maintenance crews to arrive at the scene and repair the faulted section as soon as possible. Rugged terrain and geographical layout cause some sections of power transmission lines to be difficult to reach. In the past, a variety of fault location algorithms were introduced as either an add-on feature in protective relays or stand-alone implementation in fault locators. In both cases, the measurements of current and voltages were taken at one terminal of a transmission line only. Under such conditions, it may become difficult to determine the fault location accurately, since data from other transmission line ends are required for more precise computations. In the absence of data from the other end, existing algorithms have accuracy problems under several circumstances, such as varying switching and loading conditions, fault infeed from the other end, and random value of fault resistance. Most of the one-end algorithms were ...

Energy Technology Data Exchange (ETDEWEB)

Laser-assisted processing techniques for producing high-quality solar cell metallization patterns have been investigated, developed, and characterized. During the early stages, preliminary investigations were carried out on a variety of promising laser-assisted metallization schemes, and the best of these was selected for further development. A comprehensive literature search initially yielded information on state-of-the-art laser-assisted techniques for metal deposition such as laser chemical vapor deposition and laser photolysis of organometallics, as well as laser-enhanced electroplating. Initial experiments on laser-enhanced electroplating yielded very promising results with linewidths as narrow as 25 ..mu..m and local plating speeds as high as 12 ..mu..m/s being achieved. Metal deposition experiments were carried out utilizing laser-assisted pyrolysis of a variety of metal-bearing polymer films and metallo-organic inks ...

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation on the air/water counter-current two-phase flow in a horizontal rectangular channel connected to an inclined riser has been conducted. This test-section representing a model of the hot leg of a pressurized water reactor is mounted between two separators in a pressurized experimental vessel. The cross-section and length of the horizontal part of the test-section are (0.25 m x 0.05 m) and 2.59 m, respectively, whereas the inclination angle of the riser is 50 deg. The flow was captured by a high-speed camera in the bended region of the hot leg, delivering a detailed view of the stratified interface as well as of dispersed structures like bubbles and droplets. Countercurrent flow limitation (CCFL), or the onset of flooding, was found by analyzing the water levels measured in the separators. The counter-current flow limitation is defined as the maximum air mass flow rate at which the discharged water mass flow rate is equal to the inlet ...

UK PubMed Central (United Kingdom)

OBJECTIVESAlthough several studies suggest that slow gait speed is a predictor of falls, it may also be a protective mechanism to prevent falls. Further, fast walking...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This patent describes a display unit of a speedometer for an automobile, comprising: a constant speed running circuit capable of producing output signals indicative of a desired car speed; an actual car speed operational circuit capable of producing output signals indicative of actual car speed; a comparing circuit for comparing the amplitudes of the output signals of the constant speed running operational circuit and the actual car speed operational circuit; bar graph decoders receiving the output signals from the constant speed running operational circuit and the actual car speed operational circuit; an EX-OR circuit having inputs coupled to respective bar graph decoders and having an output; and OR circuit having inputs coupled to respective bar graph decoders and having an output; selector means coupled to the output ...

International Nuclear Information System (INIS)

Given a Schwarzschild black-hole, the frame sigma at rest with respect to the Schwarzschild metric are chosen as reference-frames. In this locally non-inertial frames, a free falling body is shown to reach the speed of light on the horizon and then to travel faster-than-light inside the horizon. The usual Szekeres-Kruskal (SK) coordinates represent themselves frames that (with respect to the frames sigma) travel at subliminal speed outside, at luminal speed on, and at superluminal speed inside the horizon (so that SK frames always describe any free falling body as a standard, slower-than-light object). At last, black-holes are shown to be possible sources of tachyons.

International Nuclear Information System (INIS)

The U.S. Department of Energy's (DOE) Savannah River Site (SRS) is decommissioning many of its excess facilities through removal of the facility structures leaving only the concrete-slab foundations in place. Site-specific, risk-based derived concentration guideline levels (DCGLs) for radionuclides have been determined for a future industrial worker potentially exposed to residual contamination on these concrete slabs as described in Jannik. These risk-based DCGLs were estimated for an exposure area of 100 m2. During deactivation and decommissioning (D and D) operations at SRS, the need for area factors for larger and smaller contaminated areas arose. This paper compares the area factors determined for an industrial worker exposed to a concrete slab end-state for several radionuclides of concern at SRS with 1) the illustrative area factors provided in MARSSIM, 2) the area correction factors provided in the U.S. Environmental Protection Agency's ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents (a) an overview of the Inmos transputer and its use in parallel arrays for image processing, (b) a functional block-level description of IBM-AT-compatible boards for signal/image processing research using transputers with reconfigurable interconnection topologies, and (c) an overview of the OCCAM and C programming tools for placing parallel algorithms onto such a processor. The hardware consists of two custom printed-circuit boards (and two commercially available boards) within an IBM-AT host. The first provides a flexible input/output interface between a general-purpose high-speed input-data bus and the transputer array. The second contains 32 transputers and 4 programmable crossbar-switch interconnection chips. Several copies of the second board can be cascaded (or even partially-unpopulated) to provide for an arbitrary number of transputer chips. Each one of these boards will perform about 128 million Whetstones or, for ...

Science.gov (United States)

I review the past and present of wound ballistics research in China and look toward the future of this subject. The main points area as follows: (1) Before the 1970s, China did not conduct any experimental study on wound ballistics. (2) After the 1970s, experts in ordnance and medicine closely cooperated to conduct a series of experiments or tests on wound ballistics, such as wounding effects and the mechanism of various high-speed projectiles, the treatment of the protection from firearm wounds, high quality of ammunition design, lethality criterion, blast injuries, etc. Between 1981 and 1993, four national symposia on wound ballistics were held in China. In 1988, China sponsored the Sixth International Symposium on wound Ballistics. China has made great contributions to this subject. (3) As for the future of Chinese research on wound ballistics, I suggest strengthening the following areas: the relationship with weapons traumatology; the basic ...

Energy Technology Data Exchange (ETDEWEB)

A transient stability program was developed for the Taiwan Power Company, which has a high proportion of nuclear generation in its power system. This program offers a new territory to investigate nuclear plant effects on the power system transient stability. This program also provides a high speed tool for the Taipower system operational planning. A generalized procedure of synchronous machine modeling for a large-scale stability study is presented. The merits and weaknesses of machine modeling can be comprehended through each item of this procedure. Three types of nonlinear synchronous machine modeling implemented into this stability program are derived by following this procedure. A robust subroutine was derived to perform the fourth order Runge-Kutta integration method, making the software programming neat and systematical. For simulating the nuclear plant influence on the system, this program implemented an additional ...

International Nuclear Information System (INIS)

Cisplatin (cis-diaminedichloroplatinum [II] is a coordination compound, used in the treatment of several solid tumors. Cisplatin and its hydrolysis products exhibit a great pharmacological effect but are very toxic and probably carcinogenic. The present review summarizes the most important advances in the last years in the techniques employed for the detection and quantification of cisplatin and its hydrolysis products and in the different matrixes studied. The new emerging techniques and their modifications recently developed, fundamentally the combined use of detection and separation techniques for the analysis of platinum species and their impact on the speed, sensitivity and specificity of the analytical determination, with regard to the techniques used in the last century are discussed. High-Performance Liquid Chromatography and Capillary Electrophoresis, coupled with detection methods such as Mass Spectrometry, Inductively Coupled ...

Energy Technology Data Exchange (ETDEWEB)

Aiming to realize ball bearings operable in a vacuum and under high temperature, silicon nitride (Si3N4) ceramic ball bearings were tested. The tested ball bearings were angular contact ball bearings composed of silicon nitride with sputtered molybdenum disulfide coating using a retainer of hot-pressed self-lubricating composite material. The time variation of the frictional torque was examined for the operations under the conditions at 500{degree}C in a vacuum at a rotational speed of 600 rpm and 50N thrust load for 5{times}10{sup 7}revolutions (1400 hours) and for 1.5{times}10{sup 8}revolutions (4200 hours). Excellent tribological performance was obtained. The ball bearings are lubricated with the molybdenum disulfide film at the initial stage of the operation and with a transfer film formed from the retainer material to the balls. In a test at 650{degree}C, low and stable frictional torque was observed up to 500 hours of operation as of the ...

Energy Technology Data Exchange (ETDEWEB)

Described herein are the latest trends in rolling mill facilities toward the 21st. century and new techniques developed by Hitachi Ltd. These cover hot rolling facilities, such as two-stage twin, high crown control-roll cross mill, roll shaping machine and continuous hot rolling systems; cold rolling facilities, such as pickling line-tandem cold mill and other continuous systems; and fine steel rolling facilities, such as roll mill for very small diameter pipes and others to improve productivity and product quality. The other new techniques include systems to pursue reliability and maintainability, in which electric appliances, instruments and computers are integrated, or equipped with built-in large-capacity inverters and drivers. For hot rolling, the above techniques lead to development of a new system named Hi-HOT, which produces high-quality hot coils at a sufficient speed, while keeping rolled steel at a desired ...

Energy Technology Data Exchange (ETDEWEB)

A new filtration process using acrylic fiber has been developed which has wide applications in water works, sewage water treatment and waste water treatment facilities. Instead of sand, the common filter media in conventional systems, this new system uses long, fine acrylic fibers. Compared with a conventional system, the filtration speed and suspended solids (SS) retention of the new system have been increased 500% from 120--200 m/d to 400--1,200 m/d and from 2--3 kg/m{sup 2} to 5--20 kg/m{sup 2}, respectively. In addition, the backwash time has been decreased 60%, from 20--30 min to 10 min. As SS retention increase, the empty space between the fibers (fiber void) decreases and pressure drops due to the high filtration rate. Thus the pressure decreases rapidly after a certain period of filtration because of the increased SS retention cause fiber compression. This system is primarily based on solution clarification, but differs in that the ...

Energy Technology Data Exchange (ETDEWEB)

A press formability of magnesium alloy sheet cannot be evaluated by only general characteristics in tensile test; tensile strength, elongation n-value and r-value. For example, AZ31-alloy elongates about 20% in room temperature but breaks easily at shallow stage in deep drawing, which is caused by little local elongation (local necking). Crystallographic restriction of slip deformation in this alloy produces high strength, which almost equal to macroscopic fracture strength. In press forming, the bending under high tension requires a large deformability. A great difference in the deformability between AZ31 magnesium alloy and a strain hardened A1100 Aluminum (only 5% in elongation) is shown by static bending test with V-notch. In a rolled plate of AZ31, a crack is produced by stress concentration and propagates with reduced load at all testing temperature up to 453 K. In contrast, the point of notch in A1100 is dulled by local plastic ...

Energy Technology Data Exchange (ETDEWEB)

Success in improving hydropower project efficiency has opened more global markets for variable-speed generator technology. Manufacturers continue to test the markets as the technology evolves. The potential of variable-speed application becomes evident considering that more than 150 pumped storage plants, with a combined capacity exceeding 100,000 MW, are in operation globally.

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the anodic behavior of steels 12Kh18N10T, 10Kh17N13M2T, 08Kh22N6T, and 08Kh21N6M2T in 92% sulfuric acid. The aim of the study was to determine the parameters for anodic protection of shell-and-tube coolers. Results of the study are presented.

Energy Technology Data Exchange (ETDEWEB)

We describe the synthesis and characterization of superparamagnetic iron oxide nanoparticle based heavy metal sorbents with various surface chemistries that demonstrate an excellent affinity for the separation of heavy metals in contaminated water systems (i.e. spiked Columbia river water). The magnetic nanoparticle sorbents are prepared from an easy to synthesize iron oxide precursor, followed by a simple, one-step ligand exchange technique to introduce the organic surface functionality of interest chosen to target either specific or broader classes of heavy metals. Functionalized superparamagnetic nanoparticles are excellent sorbent materials for the extraction of heavy metal contaminants from environmental and clinical samples since they are easily removed from the media once bound to the contaminant by simply applying a magnetic field. These engineered magnetic nanoparticle sorbents have an inherently high active surface area (often > 100 ...

International Nuclear Information System (INIS)

An induced mutant, RT-10 (M6 generation) was re-irradiated with 300 Gy of gamma rays. In M2 generation a mutant plant was identified, which characterized with large pods, prominent longitudinal ribbon reticulation and slight constriction. The selected mutant, RT-1010 has the highest pod yield (.3.59 t/fed.vs.2.91 and 2.61 t/fed respectively) and harvest index ( 0.52 vs. 0.42 and 0.45 resp.), the best in fancy pods percentage (57.67 % vs. 38.33 % and 44.17 % resp.), TSMK grade (98.96 % vs. 83.03 % and 84.05 % resp.), the largest pod mass (253.37 g vs . 211.32 g and 222.19 g resp.) and the highest expected oil yield (1370 Kg/fed vs. 895.44 Kg and 868.17 Kg/fed. resp.). With regard to fatty acid compositions, both the selected mutant, RT-1010 and the parental mutant RT-10 have almost a similar high oleic fatty acid (C18:1) percentage (56.35 % and 55.103 % respectively), low linoleic fatty acid (C18:2) percentage (24.20 % and ...

Energy Technology Data Exchange (ETDEWEB)

This article presents the comparative bench testing results of a naturally aspirated, four stroke, four cylinder, water cooled, direct injection Diesel engine when running on diesel fuel and shale oil that is produced in Estonia from local oil shale. The purpose of this research is to investigate the possibility of practical usage of the shale oil as the alternative fuel for a high speed Diesel engine as well as to evaluate the combustion efficiency, brake specific fuel consumption, emission composition changes and the smoke opacity of the exhausts. Test results show that when fuelling a fully loaded engine with shale oil, the brake specific fuel consumption at the maximum torque and rated power is correspondingly higher by 12.3% and 20.4%. However, the brake thermal efficiencies do not differ widely and their maximum values remain equal to 0.36-0.37 for Diesel fuel and 0.32-0.33 for shale oil. The total nitrogen oxide emissions from the shale ...

International Nuclear Information System (INIS)

It is well known that one of the main advantages of the high speed forming (HSF) processes is the improvement in the forming limits of the used materials.Using the Electromagnetic Forming (EMF) technology two materials have been tested with different mechanical and physical properties: the AA5754 aluminium and the AZ31B magnesium alloys.The EMF process principle can be described as follows: A significant amount of electrical energy is stored in a bank of capacitors which are suddenly discharged releasing all the stored energy. This electric discharge runs through a coil which generates an intense transient magnetic field. At the same time transient Eddy currents are induced in the electrically conductive part placed some millimetres far from the coil. Another intense magnetic field is generated due to those Eddy currents but on the opposite direction as the one generated by the coil. A big magnetic repulsion force is created between the part ...

Energy Technology Data Exchange (ETDEWEB)

Primary dendrite spacings, secondary dendrite spacings, and microsegregation have been examined in PWA-1480 single crystal specimens which were directionally solidified during parabolic maneuvers on the KC-135 aircraft. Experimentally observed growth rate and thermal gradient dependence of primary dendrite spacings are in good agreement with predictions from dendrite growth models for binary alloys. Secondary dendrite coarsening kinetics show a reasonable fit with the predictions from an analytical model proposed by Kirkwood for a binary alloy. The partition coefficients of tantalum, titanium, and aluminum are observed to be less than unity, while that for tungsten and cobalt are greater than unity. This is qualitatively similar to the nickel base binaries. Microsegregation profiles experimentally observed for PWA-1480 superalloy show a good fit with Bower, Brody, and Flemings model developed for binary alloys. Transitions in gravity levels do not appear to affect primary dendrite ...

Energy Technology Data Exchange (ETDEWEB)

Wind speed has been measured in Patenga, Cox`s Bazar, Kuakata, Moheshkhali, and Noakhali by the computerized anemometers. The wind computers have been installed at 20 meters height. According to this study annual average wind speeds in the coastal regions of Bangladesh are greater than 6.5 m/s at the height of 20 meters. It has been observed that during day times (8 a.m. to 7 p.m.) wind speeds are about 30 to 40% higher than the average values. The value of the power exponent {alpha} has been determined in the above sites and it is 0.139. So, at 40 meters height the annual average wind speed is about 7.15 m/s. So, wind speeds in the coastal regions of Bangladesh are suitable for both water pumping and electricity generation. Details are given in this paper with graphical and analytical representations. (author)

Energy Technology Data Exchange (ETDEWEB)

Swirling speed in a direct injection diesel engine was measured by a laser doppler velocimeter. Intake port geometry and engine speed were changed as factors affecting the swirling flow to study the distribution of swirling flow speed. The distribution of swirling flow speed changes complicatedly owing to axial nonsymmetry during intake process but becomes simple shape of axial symmetry during compression process after closing intake valve. But if this is assumed as the rigid swirl shape, the difference due to each intake port cannot be expressed but also large error may be possible to appear close to the cylinder wall. The distribution of swirling flow speed during compression process changes similarly, nearly proportinal to engine speed. But the similarity is higher at the middle period in compression process than at the end period in compression period. Axial ...

Energy Technology Data Exchange (ETDEWEB)

Nitriding leads to improved tribological and corrosive properties of iron alloy components. In order to study the effect of plasma nitriding parameters on the structure of compound layer and diffusion zone, a systematic variation of process parameters, temperature and process gas atmosphere has been carried out. Metallographic inspection, X-ray diffraction and glow discharge optical spectroscopy analysis (GDOES) were used in this investigation. The results clarified that depending on the amount of nitrogen in the gas atmosphere nitrided layers with and without compound layer can be generated in the surface of M2 tool steel for temperatures from 350 C to 500 C. For plasma nitriding in 5 vol.% Nitrogen and 95 vol.% Hydrogen no compact compound layer was formed. The gas mixture of 76 vol.% Nitrogen resulted in compound layer formation for all temperatures from 350 C to 500 C. X-ray phase analysis indicated an almost 100% {epsilon}-(carbo)nitride ...

Energy Technology Data Exchange (ETDEWEB)

High-spatial-resolution microfocus-based X-ray imaging technology, both real-time and film, has been used to study the thickness variation that occurs in the oxide core of silver-sheathed BSCCO ribbons produced by the powder-in-tube method. This thickness variation (also called ``sausaging``) occurs during incremental rolling and degrades the critical current densities of the ribbons. Using X-ray image data the authors determined the onset and severity of sausaging. Onset occurred at a ribbon thickness of 203 {micro}m, and the severity increased with subsequent rolling reductions. Scanning electron microscopy was used to confirm the X-ray image data. X-ray imaging provides several advantages over more traditional methods for characterizing the superconductors such as optical or scanning electron microscopy. The X-ray imaging provides nondestructive information about the entire width of the ribbon, with far greater speed, lower cost, and more ...

International Nuclear Information System (INIS)

A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial extent of each flow regime decreases with increasing gas velocity through the ...

Energy Technology Data Exchange (ETDEWEB)

Discussed in this report is a wavefield simulation in the 3-dimensional seismic survey. With the level of the object of exploration growing deeper and the object more complicated in structure, the survey method is now turning 3-dimensional. There are several modelling methods for numerical calculation of 3-dimensional wavefields, such as the difference method, pseudospectral method, and the like, all of which demand an exorbitantly large memory and long calculation time, and are costly. Such methods have of late become feasible, however, thanks to the advent of the parallel computer. As compared with the difference method, the pseudospectral method requires a smaller computer memory and shorter computation time, and is more flexible in accepting models. It outputs the result in fullwave just like the difference method, and does not cause wavefield numerical variance. As the computation platform, the parallel computer nCUBE-2S is used. The object domain is divided into the number of the ...

International Nuclear Information System (INIS)

The Flory model is applied to predict the isobaric expansion coefficients, ?P, isentropic, ?S, and isothermal, ?T, compressibilities and speeds of sound, u, of the highly complex mixtures: hydroxyether + alkane, + dibutylether, + 1-butanol or + 2-methoxyethanol, 1-alkanol + alkane, and 1-alkanol + dibutylether. Predictions were obtained using the energetic parameter, ?12, determined from values of excess enthalpies, HE, and from values of the excess isochoric internal energies, UVE, at equimolar composition. No meaningful differences exist between such predictions. Deviations between experimental and calculated values are lower than 2% for mixtures containing alkoxyethanols. Poorer results are obtained for 1-alkanol + dibutylether mixtures with deviations up to 5%. It is shown that predictions on ?P, ?S, ?T, and u essentially depend on structural effects and not on the orientational effects present in the studied mixtures. Results are improved ...

Energy Technology Data Exchange (ETDEWEB)

Results of an investigation aiming to study the effects of the burner cap design factors on flame stability are presented in this paper. Flame stability is an essential part of the operation of all domestic burners, including natural gas-fired cooktops. At high thermal inputs flame lifts are encountered above certain levels of primary aeration, whereas flashback only takes place at low thermal inputs, due to natural gas low flame speed, above certain levels of primary aeration. In this work, flame lift limits were measured at 3.3 kW thermal input and the highest primary aeration above which flame lifts started to become visible was the stability limit at this thermal input. Around 60% primary aeration was desired to minimize pollutant emissions. Turndown tests were done at 40% primary aeration. The `Factorial Experimental Design` method with statistical analysis was used. This enabled detection of interactions between factors as well as the ...

Energy Technology Data Exchange (ETDEWEB)

As silicon-integrated circuit technology enters the sub-100 nm realm, continued progress will depend on a fundamental understanding of the physics of materials processing. The high cost of processing experimental lots and the speed at which new devices must be brought to the market have created a new emphasis on realistic physical models incorporated in technology CAD (TCAD) simulation tools. The volume bring together materials scientists, TCAD researchers and silicon technologists to review recent developments in the integrated-circuit community and to identify key issues for future research in this field. Results of research on the physical mechanisms involved in silicon device processing is presented both from experimental and theoretical viewpoints. The application of this fundamental research to TCAD process simulation models is also addressed. Topics include: shallow junctions and transient enhanced diffusion; extended defects and ...

Energy Technology Data Exchange (ETDEWEB)

The durability of ball bearings, 32-mm- and 45-mm-bore, with a retainer or glass cloth-polytetrafluoroethylene (PTFE) laminate was tested under a high radial load at a speed of 20,000 rpm in LOX or LN2. The retainers were characterized as good self-lubricators because the abrasive glass-cloth fiber tips exposed on the retainer were chemicaly etched away with hydrofluoric acid (HF). During testing, the bearing-cartridge-acceleration was monitored to detect bearing damage. Testing in LOX for about 2.2 hr showed that excellent lubricating conditions were obtained for all bearings. Testing in LN2 for about 5.1 hr detected that the fatigue life of the bearing was about the same as the calculated B10 fatigue life. The HF chemical treatment resulted in a reacted fluoride-oxide material which remained in the etched part of the glass fiber. Several chemical products, particularly MgO, CaO, and CaCO3, enhanced adhesion of PTFE transfer film to the ...

Energy Technology Data Exchange (ETDEWEB)

Neutron radiography is a non-destructive test method to examine a material by using the dependency of neutron attenuation on the nuclear characteristics of the atoms composing the object material. There are two categories of neutron radiography; static neutron radiography and dynamic neutron radiography. The static neutron radiography is a technique to observe a standing object by using a camera or a film cassette. The dynamic neutron radiography(DNR) is a technique to observe a moving object usually by using a camera. Depending on the camera frame rate, the dynamic neutron radiography is categorized into the real time neutron radiography(RTNR) and the high speed neutron radiography(HSNR). The frame rate for RTNR is 30 frames/s and that for HSNR is usually more that 500 frames/sec. Thus, RTNR is good for observing time-averaged phenomena and HSNR is good for observing instantaneous phenomena. DNR is a powerful tool for fluid visualization as ...

Energy Technology Data Exchange (ETDEWEB)

In the Institute for Atomic Energy, Rikkyo University, just after the TRIGA-2 research reactor of 100 kW has attained the criticality, the cylindrical box for neutron radiography (NR) irradiation was made in the attached pool, and the research on NR was started in 1961. Thereafter in 1985, the vertical irradiation pipe was installed in the reactor tank, and the experiment for collecting the basic data was begun. In 1986, based on the obtained data, the NR irradiation facility on full scale was installed in No. 2 tangential horizontal experimental hole. As the main NR irradiation facilities, the vertical neutron irradiation pipe, the use of which is stopped now, the NR facility using the horizontal experimental hole (RUR/N2), the irradiation facility and ancillary facilities such as beam shutter, beam catcher and hoist are described. As the main equipments for NR, the imaging apparatuses of cooled type CCD, SIT and superhigh sensitivity, the image processors of C3366 interface, ...

International Nuclear Information System (INIS)

SAFT-UT technology is shown to provide significant enhancements to the inspection of materials used in US nuclear power plants. This report provides guidelines for the implementation of SAFT-UT technology and shows the results from its application. An overview of the development of SAFT-UT is provided so that the reader may become familiar with the technology. Then the basic fundamentals are presented with an extensive list of references. A comprehensive operating procedure, which is used in conjunction with the SAFT-UT field system developed by Pacific Northwest Laboratory (PNL), provides the recipe for both SAFT data acquisition and analysis. The specification for the hardware implementation is provided for the SAFT-UT system along with a description of the subsequent developments and improvements. One development of technical interest is the SAFT real time processor. Performance of the real-time processor is impressive and comparison is made of this dedicated parallel processor to a ...

CERN Document Server

Two headed motor proteins, such as kinesin and dynein, hidrolyze environmental ATP in order to propel unidirectionally along cytoskeletal filaments such as microtubules. In the case of kinesin, protein heads bind primarily on the alpha tubulin site of asymmetric alpha-beta 8nm-long tubulin dimers that constitute the microtubular protofilaments. Kinesin dimers overcome local binding forces up to 5pN and are known to move on protofilaments with ATP concentration-dependent speeds while hydrolizing on average one ATP molecule per 8nm step. The salient features of protein trajectories are the distinct abrupt usually 8nm-long steps from one tubulin dimer to the next interlaced with long quiescent binding periods at a tubulin site. Discrete walks of this type are characterized by substantially reduced variances compared to pure biased random walks, and as a result rule out flashing-type ratchet models as possible mechanisms for motor movement. On the other hand, simple ...

Energy Technology Data Exchange (ETDEWEB)

To improve the surface properties of magnesium alloy, a lining process using shot peening was carried out. The lining of magnesium alloy with metals such as titanium and nickel is useful in heightening the corrosion and wear properties for the components. In the shot peening experiment, the foil set on the magnesium workpiece is pelted with many shots at a high velocity. The foil is bonded to the surface of the workpiece due to plastic deformation induced by the collision of the shots. A pure aluminum foil is inserted between the hard foil and magnesium workpiece to assist the bonding. To heighten the bondability, the foil and workpiece are heated and the flow stresses of the metals are reduced. In this experiment, a centrifugal shot peening machine with an electrical heater was employed. The workpieces were commercially magnesium alloys AZ31B and AZ91D, and the foils were commercially pure aluminum, pure titanium and pure nickel. The effects of collision ...

Energy Technology Data Exchange (ETDEWEB)

This report describes development of an electronic system designed to reduce vibration generated by a cryocooler. The diminished vibration makes it practical to use the active cooler to extract heat from a portable gamma ray detector instrument. The system was developed for a Sunpower cryocooler with an integrated counterbalance mass. The overall momentum cancellation approach is also applicable to other similar cryocoolers. The cancellation system is an assembly of several components tailored to accomplish the required vibration reduction with minimum power consumption and volume. It is designed to be powered by a 18--32 Volt battery. Up to ten harmonics of the 58.65 Hz drive frequency are controlled. In addition to the vibration cancellation, the electronic system produces the drive signal for the cryocooler and regulates the cooler temperature. The system employs a sinusoidal drive to reduce the amount of higher harmonic vibration. A digital signal processor (DSP) is used to perform ...

Energy Technology Data Exchange (ETDEWEB)

Genetic mapping is approached using the techniques of high resolution fluorescence in situ hybridization (FISH). This technology and the results of its application are designed to rapidly generate whole genome as tool box of expressed sequence to speed the identification of human disease genes. The results of this study are intended to dovetail with and to link the results of existing technologies for creating backbone YAC and genetic maps. In the first eight months, this approach generated 60--80% of the expressed sequence map, the remainder expected to be derived through more long-term, labor-intensive, regional chromosomal gene searches or sequencing. The laboratory has made significant progress in the set-up phase, in mapping fetal and adult brain and other cDNAs, in testing a model system for directly linking genetic and physical maps using FISH with small fragments, in setting up a database, and in establishing the validity and throughput ...

International Nuclear Information System (INIS)

Electricite de France, (EDF) in the late sixties and China through 10. 5-year Plan adopted the same approach of standardized NPPs to benefit from the series effect and to increase and speed up self reliance and localization. This approach also allows to continuously gather the feedback from design, construction and operation and to use it to constantly improve future and present nuclear power plants, by optimizing design features, construction phase and generation performances for safety, quality, cost and schedule aspects. Daya Bay NPP put into commercial operation in 1994 is posting high level safety and operation results. At Ling Ao NPP Chinese engineers of LANPC, with the contribution of the Chinese industry, have efficiency and successfully managed engineering, construction and operation preparation. GNPJVC / LANPC and EDF are developing permanent and mutual experience feedback exchanges in all areas of engineering, maintenance and ...

International Nuclear Information System (INIS)

The industrial radiation processing using low energy electron beam (EB) accelerators lower than 300 keV offers high speed, safe technologies for the chemical conversion of thin layer coatings. Because of the nonselective mode of initiating chain reaction polymerization involving free radicals in synthetic coating layers and suitable substrates, the EB curing of the coatings on woods and papers has particular advantage. Hungary decided to start an up-to-date EB line to process cement-bound (CB) wood chipboards with pigmented acrylic coatings. The CB wood chipboards contain more than 60 % of portland cement and up to 40 % of wood particles. They are produced as large boads of 6 - 16 mm thickness. In their fireproof character and other aspects, they are similar to asbestos-cement boards without containing carcinagenic asbestos, and are stable against moisture and atmospheric influences. EB-cured acrylate coating improved further those properties, ...

Science.gov (United States)

The objective of the program is to develop a domestic cooktop with low-NOx emissions and high efficiency. During the first two phases of the program, three design concepts were developed, and two versions of developmental prototypes using the IR-Jet approach were fabricated and tested. The third phase was initiated to address the design issues of burner turndown and modulation and to conduct the field test of a prototype with one IR-Jet and three conventional burners. Two prototypes containing one IR-Jet and three conventional burners and utilizing blower speed control for air/gas modulation were fabricated. One unit employed a brushless dc motor and the other a 2-pole ac motor. The ac motor prototype was field tested. Field testing showed the need for a mechanical air/gas valve for modulation and for a 1500 Btu/hr simmer setting. A 4-inch-diameter stepped-tile configuration provided input rates from 1500 to 8000 Btu/hr. A manufacturer, Copreci ...

CERN Document Server

(Abridged) We use 3D SPH calculations with higher resolution, as well as with more realistic viscosity and sound-speed prescriptions than previous work to examine the eccentric instability which underlies the superhump phenomenon in semi-detached binaries. We illustrate the importance of the two-armed spiral mode in the generation of superhumps. Differential motions in the fluid disc cause converging flows which lead to strong spiral shocks once each superhump cycle. The dissipation associated with these shocks powers the superhump. We compare 2D and 3D results, and conclude that 3D simulations are necessary to faithfully simulate the disc dynamics. We ran our simulations for unprecedented durations, so that an eccentric equilibrium is established except at high mass ratios where the growth rate of the instability is very low. Our improved simulations give a closer match to the observed relationship between superhump period excess and binary ...

Energy Technology Data Exchange (ETDEWEB)

Bluestein's Fast Fourier Transform (FFT), commonly called the Chirp-Z Transform (CZT), is a little-known algorithm that offers engineers a high-resolution FFT combined with the ability to specify bandwidth. In the field of digital signal processing, engineers are always challenged to detect tones, frequencies, signatures, or some telltale sign that signifies a condition that must be indicated, ignored, or controlled. One of these challenges is to detect specific frequencies, for instance when looking for tones from telephones or detecting 60-Hz noise on power lines. The Goertzel algorithm described in Embedded Systems Programming, September 2002, offered a powerful tool toward finding specific frequencies faster than the FFT.Another challenge involves analyzing a range of frequencies, such as recording frequency response measurements, matching voice patterns, or displaying spectrum information on the face of an amateur radio. To meet this challenge most ...

Science.gov (United States)

Magnetic drug targeting, using core-shell magnetic carrier particles loaded with anti-cancer drugs, is an emerging and significant method of cancer treatment. Gold shell-iron core nanoparticles (Fe@Au) were synthesized by the reverse micelle method with aqueous reactants, surfactant, co-surfactant and oil phase. XRD, XPS, TEM and magnetic property measurements were utilized to characterize these core-shell nanoparticles. Magnetic measurements showed that the particles were superparamagnetic at room temperature and that the saturation magnetization decreased with increasing gold concentration. The anti-cancer drug doxorubicin (DOX) was loaded onto these Fe@Au nanoparticle carriers and the drug release profiles showed that upto 25% of adsorbed drug was released in 80 h. It was found that the amine (-NH2) group of DOX binds to the gold shell. An in vitro apparatus simulating the human circulatory system was used to determine the retention of these nanoparticle carriers when exposed to an ...

Energy Technology Data Exchange (ETDEWEB)

Distance protection, differential protection and directional comparison schemes are presently used for protecting transmission lines. Directional comparison relays are set to respond to faults in the protection zone without intentional time delay and are, therefore, used where high-speed fault clearing is needed. Artificial Neural Networks (ANNs) can handle most situations which cannot be defined sufficiently for finding a deterministic solution. The design and testing of an ANN for directional comparison protection of transmission lines are presented in this paper. Training patterns were generated using voltage and current samples for faults at various locations along a transmission line. The faults were simulated using an electromagnetic transient program and a sample three-phase power system. The performance of the proposed discriminator was checked using data simulated for testing and the fault data recorded from 240 kV and 500 kV lines. Some of the test ...

Energy Technology Data Exchange (ETDEWEB)

Wind power is an increasingly significant renewable energy resource, producing no environmentally damaging CO2 emissions. The efficient production of electricity by wind turbines relies on aerodynamics. Aerodynamics of Wind Turbines provides the fundamental solutions to efficient wind turbine design. Following a historical introduction, Part 1 of Aerodynamics of Wind Turbines is concerned with basic rotor aerodynamics, while Part 2 deals with structural aspects of the wind turbine and calculation of the loads on it. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. Aerodynamics of Wind Turbines is an essential reference for both engineering ...

International Nuclear Information System (INIS)

The authors discuss a two-phase two-component experimental system developed to study enhancement of heat transfer from a vertical chip size heater to surrounding liquid (Freon 113 or Ethanol) due to air jet impingement. Heat transfer coefficient was measured as function of jet velocity, heat flux and the distance between exit of jet tube and heated surface. The injector was placed very close to the hot surface. It was found that the heat transfer was notably enhanced with foreign gas impingement, especially in the cases of small temperature differences between wall and coolant. In fact for higher jet velocities the heat transfer coefficients tended to infinite while the temperature differences between wall and coolant were zero. The heat transfer coefficients decreased with the increasing of heat flux. High-speed camera was used to study the behaviour of the gas bubbles which play very important role in the heat transfer process. A physical model of simultaneous ...

CERN Document Server

We find an exact analytic solution for the time evolution of a three Dirac neutrino system adiabatically oscillating in matter, constructing explicitly the relevant 3\\times 3 mixing matrix in matter. Using this result we investigate the solar neutrino data in a scenario where the neutrino masses are such that m_1\\alt m_2\\ll m_3, taking into account several phenomenological constraints on neutrino mixing angles and masses. A solution of the solar neutrino problem for large values of the parameter \\delta m^2=m_2^2-m_1^2 which are not usually associated with a resonance is found. This is an essentially three-generation effect.

International Nuclear Information System (INIS)

Determination of the specific surface of uranium oxides: UO_2 and U_3O_8 using a simplified equation derived from the Brunauer, Emmett and Teller theory. The method is suitable for samples having a surface between 6 to 50 m"2.

International Nuclear Information System (INIS)

Radon has been recognized by various international health organizations as a major lung carcinogen. The onset of cellular carcinogenesis involves DNA damage to bronchi epithelial cells by particles emitted by radon progeny. Radon diffusion is an important release mechanism for radon that is produced inside a building material. The physical parameter that characterizes this process is the radon diffusion Coefficient D(m-2 s-l). The diffusion constant and Diffusion length has been measured as 2.15xl0- 6 m-2s-1, 1.01m for soil, 1.65x10-6m-2s-1, 0.89m for sand and 0.21x 10-6m-2s-1, 0.31m for crush aggregate saudi building materials respectively. The values are found to be minimum for crush aggregates, which shows that crush aggregate is least permeable to radon flow as compared with the other building materials studied. ...

International Nuclear Information System (INIS)

The effects of focused-ion-beam (FIB) irradiation on writer performance were examined on a perpendicular recording system. The entire top pole was irradiated by FIB with ion doses from 0 to 300 pC/#mu#m"2. PW_5_0 and signal to noise ratio (SNR) were characterized using a spin stand before and after FIB irradiation. It was found that there is degradation of PW_5_0 and SNR due to FIB irradiation. At the maximum dose (300 pC/#mu#m"2), PW_5_0 increased by 33 nm (>30%) and SNR decreased by 5 dB (>25%). The degradation was attributed to the physical pole tip recession and the formation of a magnetic dead layer. The thickness of the magnetic dead layer was estimated by analyzing the write spacing loss. Using atomic force microscopy and stage current change monitored during FIB process, it was found that the entire 4-nm protective carbon layer was etched away with a dose of 25 ...

British Library Electronic Table of Contents (United Kingdom)

The juvenile fish community associated with natural, degraded and replanted Sonneratia alba mangroves in Gazi Bay was sampled during the South East and North East monsoons between April 2002 and June 2003. A total of 1800 individuals belonging to 49 taxa and 34 families were collected from the intertidal forest using stake nets. Fish abundance ranged from 0.93+-0.20ind. m-2 (SEM02) to 1.16+-0.18ind. m-2 (SEM03) between seasons and between 0.54+-0.07ind. m-2 and 1.64+-0.33ind. m-2 for individual sites across seasons. Five taxa accounted for approximately 70% of the total fish abundance, with Gobidae and Gerres oyena dominating. ANOSIM revealed seasonal differences in fish species composition and abundance (p=0.01) due to fluctuating abundances of primarily Terapon sp. and Thryssa sp. The ma...

Energy Technology Data Exchange (ETDEWEB)

Recent research work on adjustable speed pumped storage plants conducted in Japan, the USA and Europe suggests that they have many advantages over fixed-speed plants, and can contribute to power system regulation even in pump mode. This paper describes two types of static frequency converter for such pumped storage plants, especially those with greatly fluctuating heads. The design characteristics and operation of the doubly fed induction machine and the synchronous machine with DC link converter are set out and the devices compared. (UK)

International Nuclear Information System (INIS)

Field experiments were conducted in the 30-km zone of Gomel's region of the Byelorussia to study factors aecting a biological radionuclide accessibility. A contamination density by radiocesium equaled 2,7-9,9 MBk/m"2, strontium 90 - 0,3-0,5 MBk/m"2 in 1991. A sowing of oats barley, lupin was carried out. It was shown that radionuclide accumulation by agricultural plants was determined basically by biological peculiarities of plants in greater degree than by the contamination density. It was shown that strontium 90 migration from the soil was more intensive than that of radiocesium. 8 tabs.

British Library Electronic Table of Contents (United Kingdom)

We revisit a recently proposed agent-based model of active biological motion and compare its predictions with own experimental findings for the speed distribution of bacterial cells, Salmonella typhimurium. Agents move according to a stochastic dynamics and use energy stored in an internal depot for metabolism and active motion. We discuss different assumptions of how the conversion from internal to kinetic energy d(v) may depend on the actual speed, to conclude that d 2 v ? with either ? = 2 or 1 ? < 2 are promising hypotheses. To test these, we compare the model?s prediction with the speed distribution of bacteria which were obtained in media of different nutrient concentration and at different times. We find that both hypotheses are in line with the experimental observations, with ? bet...

Science.gov (United States)

complete verification of the Garrick-Watkins theory for the effect of forward speed on the ..... By W. S. Hyler, R A. Lewis, and 11 J. Grover. ...

Science.gov (United States)

No Abstract Available