Energy Technology Data Exchange (ETDEWEB)

The X-ray diffraction analysis of (U,Ce)O{sub 2} with the CeO{sub 2} contents ranging from 0 to 20 mol% CeO{sub 2} was performed at room temperature to obtain the variation in the lattice parameter with the CeO{sub 2} content. Ultrasonic pulse echo measurements were also carried out to estimate the change in the mechanical properties of (U,Ce)O{sub 2} with the CeO{sub 2} content. The lattice parameter of (U,Ce)O{sub 2} was found to decrease with increasing CeO{sub 2} content. The variation in the lattice parameter with the CeO{sub 2} content closely followed the Vegard law. The shear and longitudinal velocities in (U,Ce)O{sub 2} were found to decrease with increasing CeO{sub 2} content. The Young`s and shear moduli, and Poisson`s ratio estimated from the wave velocities decreased with the CeO{sub 2} content. No mechanical property showed anomaly in low CeO{sub 2} content region. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98. The developed thermally conductive grout consists of cement, water, a particular grade of silica sand, superplasticizer and a small amount of bentonite. While the primary function of the grout is to facilitate heat transfer between the U-loop and surrounding formation, it is also essential that the grout act as an effective borehole sealant. Two types of permeability (hydraulic conductivity) tests was conducted to evaluate the sealing performance of the cement-sand grout. Additional properties of the proposed grout that were investigated include bleeding, shrinkage, bond strength, freeze-thaw ...

Energy Technology Data Exchange (ETDEWEB)

Glasses in the system (95-x) [0.25 Na{sub 2}O-0.75 B{sub 2}O{sub 3}]-x P{sub 2}O{sub 5}-5 Fe{sub 2}O{sub 3} (0<=x<=15 mol%), have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of P{sub 2}O{sub 5} on the structure of the glass system. Elastic properties Poisson's ratio, micro-hardness and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz (both longitudinal and shear) at room temperature. The results showed that the density and the molar volume increase as both sound velocities and the determined glass transition temperatures decrease with increasing the contents of P{sub 2}O{sub 5}. Infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of P{sub 2}O{sub 5} content as a second network former. These results are ...

International Nuclear Information System (INIS)

A photoacoustic (PA) imaging system based on an ultrasonic Fresnel zone plate (FZP) transducer is developed for the purpose of imaging biological tissue. This FZP transducer has a two-zone negative zone plate piezoelectric material pattern, and an optical fibre is integrated with the transducer on the symmetric axis of the zone plates to deliver laser pulses to the sample. The focal characteristic of the FZP transducer is analysed by theoretical prediction and experimental measurement, and the measured results are in good agreement with the predicted results. The limited-field back-projection deconvolution algorithm combined with the coherence-factor weighting technique is used to reconstruct the optical absorption distribution. The experiments were performed with phantoms and the blood vessels of chicken embryo chorioallantoic membrane. The results demonstrate that PA imaging using the FZP transducer has the ability to image biological tissue ...

CERN Document Server

Using spectral hole-burning-based ultraslow group velocity in a dilute solid medium, we report enhanced photon echo efficiency three orders of magnitude higher than that in a nonslow light regime. The enhancement is due to exponentially increased absorption of an optical data pulse owing to the enhanced photon-atom interaction in an ultraslow light regime, whereas echo reabsorption is negligibly small due to group-velocity dependent population depletion.

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.

DEFF Research Database (Denmark)

Previous investigations have shown promising results in using the directional cross-correlation method to estimate velocity vectors. The velocity vector estimate provides information on both velocity direction and magnitude. The direction is estimated by beamforming signals along directions in the range $[0^{\\circ}; 180^{\\circ}[$ and identifying the direction that produces the largest correlation across emissions. An estimate of the velocity magnitude is obtained from the spatial shift between signals beamformed along the estimated direction. This paper expands these investigations to include estimations of the vector velocities of a larger region by combining the estimations along several scan lines. In combination with a B-mode image, the vector velocities are displayed as an image of the investigated region with a color indicating the magnitude, and arrows ...

Science.gov (United States)

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca(2)+ in the cytoplasm (Ca(2)+(cyt)). The present measurements of Ca(2)+(cyt) during membrane excitation show that stimulating pulses of low magnitude (subthreshold pulse) had no perceivable effect on Ca(2)+(cyt). When the strength of a pulse exceeded a narrow threshold (suprathreshold pulse) it evoked the full extent of the Ca(2)+(cyt) elevation. This suggests an all-or-none mechanism for Ca(2)+ mobilization. A transient calcium rise could also be induced by one subthreshold pulse if it was after another subthreshold pulse of the same kind after a suitable interval, i.e., not closer than a few 100 ms and not longer than a few seconds. This dependency of Ca(2)+ mobilization on single and double pulses ...

CERN Document Server

It is shown that the interpretation of the experimental results reported in the publication "Storage of Light in Atomic Vapor" by D.F.Phillips et al., Phys. Rev.Lett. 86, 783 (2001) [quant-ph/0012138] is incorrect. The experimental observation of this paper can be consistently explained in the framework of standard concepts of the physics of optical pumping and has nothing to do with "storage of light", or "dynamic reduction of the group velocity", or "light pulse compression".

Energy Technology Data Exchange (ETDEWEB)

The propagation of acoustic pressure perturbations in an adiabatic low-quality air/water flow were investigated both theoretically and experimentally. A linearized dispersion model is correlated with data to extract information on the behavior of interfacial momentum transfer controlled by the virtual volume coefficient. The dispersion model is examined in limiting cases of low and high frequency and related to current models for critical flow velocity. Fourier decomposition techniques are employed to predict the dispersion of measured pressure pulses and to relate data for standing waves and propagating pulses. The dispersion model is based on a two-fluid model and is the most complete model available in the literature at this time. The dispersion data presented herein is also the best available to date for low frequency (i.e., frequencies less than bubble resonance) sound propagation in bubbly air/water mixtures.

Energy Technology Data Exchange (ETDEWEB)

A new test methodology is described which allows access to loading rates that lie between split Hopkinson bar and shock-loading techniques. Gas gun experiments combined with velocity interferometry techniques have been used to experimentally determine the intermediate strain-rate loading behavior of Coors AD995 alumina and Cercom silicon-carbide rods. Graded-density materials have been used as impactors; thereby eliminating the tension states generated by the radial stress components during the loading phase. Results of these experiments demonstrate that the time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod. This allows access to intermediate loading rates over 5 x 10{sup 3}/s to a few times 10{sup 4}/s.

Science.gov (United States)

Linearly polarized laser radiation accelerates electrons to very high velocities and these electron form a sheath layer on the rear side of thin targets where preferentially protons are accelerated. When mass-limited targets are used, the lateral transport of the absorbed laser energy is reduced and the accelerating field is enhanced. For targets consisting of two ion species, heavier ions facilitate formation of quasi-monoenergetic bunch of lighter ions. For circularly polarized light, fast electron production is suppressed by the absence of the oscillatory component of the ponderomotive force. Ions are accelerated on the front side by the separation field and very thin foil can be accelerated as one massive quasi-neutral block. As all ion species acquire the same velocity, this acceleration mechanism is preferred for heavier ions.

International Nuclear Information System (INIS)

Thomson scattering is the process in which a low-energy photon scatters from a free electron. When a laser pulse propagates through a plasma, the spectrum of the scattered light due to the Thomson scattering is proportional to the power spectrum of the electron density fluctuations, i.e., dynamic form factor, from which various plasma parameters can be inferred, such as electron temperature and plasma flow velocity. After years of development. Thomson scattering has now become a powerful diagnostic tool of plasma physics. (authors)

UK PubMed Central (United Kingdom)

Measurements are reported of ultrasonic acoustic emissions (AEs) measured from sapwood samples of Thuja occidentalis L. and Tsuga canadensis (L.) Carr. during air dehydration....Full Text Available

International Nuclear Information System (INIS)

The report summarizes ten years of experience in the analysis and evaluation of ultrasonic testing data measured in turbine and generator rotors. Apart from the information on type, position, size and distribution of flaws, the expert knowledge achieved in an interpretation of ultrasonic signals yields further insight, as e.g.: - Confirmation of assumptions taken as a basis for fracture-mechanical analysis of these flaws with regard to crack initiation and crack growth under low-cycle fatigue conditions (O=0.7-1 Rp 0.2, N<25.000 growth in length); - enhanced information on a correlation of ultrasonic testing data with the real flaw size. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Methods of designing ultrasonic piezoelectric transducers in accord with a specified directivity pattern are analyzed and general formulas are presented for the design problem. As an example, the pressure distribution on the working surface of a circular piezoelectric transducer is determined that is capable of forming a narrow weakly divergent beam. Experimental results are presented with respected to ultrasonic fields that support the theoretical conclusions.

International Nuclear Information System (INIS)

This report focuses on a better understanding of the physical phenomenon related to the enhancement of boiling and non-boiling heat transfer by applying ultrasonic waves. Experimental results obtained both in a pool of water and in a vertically upward water flow proved clearly that macroscopic acoustic steam induced by ultrasonics is a major contribution to heat transfer augmentation. (author).

Energy Technology Data Exchange (ETDEWEB)

Effect of ultrasonic-wave irradiation on the Mn-Zn ferrite powder suspension prepared by solid-state reaction and alcoholic dehydration methods was investigated. Size, distribution, and morphology of the powders prepared at different temperatures were examined, as a function of irradiation time. It was observed that the powders were reduced in size by ultrasonic energy through distinct routes. 8 refs., 7 figs., 1 tab.

International Nuclear Information System (INIS)

Early effects of 100 Kilorads of X-rays on muscle cell membrane properties have been measured in sartorius muscles from Leptodactylus ocellatus. Threshold strength for rectangular current pulses increased 10% after irradiation, and action potential propagation velocity decreased 10%. Passive membrane parameters were calculated from potential responses to sub-threshold current pulses, assuming conventional cable theory. Specific membrane conductance increased to 18% after irradiation, membrane capacitance increased 14%, and length constant decreased 10% but membrane time constant was unchanged. Cell diameter decreased 5%, and resting membrane potential decreased 8%. Membrane parameters during an action potential were also evaluated by the phase-plane and current-voltage plot techniques. Irradiation significantly decreased the action potential amplitude, the excitation potential, and the maximum rates of rise and fall of ...

CERN Document Server

(abridged) Observations clearly show that low-mass AGB stars can provide a nucleosynthesis site of the s-process. Recent stellar evolution models indicate that radiative burning of C13 between thermal pulses in low-mass AGB stars may indeed provide the needed neutrons. Some mixing between the proton-rich envelope and the carbon-rich core may lead to the production of C13. However, the responsible physical mechanism is not yet unambiguously identified. We present stellar model calculations with overshoot and rotation. Overshoot, with a time-dependent and exponentially decaying efficiency, leads to a partial mixture of protons and C12 during the third dredge-up. According to the depth-dependent ratio of protons and C12, a small C13-pocket forms underneath a N14-rich layer. Overshoot does not allow for any mixing during the interpulse phase. Rotation introduces mixing driven by large angular velocity gradients which form at the envelope-core ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this program was to characterize Time Of Arrival Detectors (TOAD) pins response to shock loading with respect to risetime, amplitude, repeatability and consistency. TOAD pins were subjected to impacts of 35 to 420 kilobars amplitude and approximately 1 ms pulse width to investigate the timing spread of four pins and the voltage output profile of the individual pins. Sets of pins were also aged at 45{degrees}, 60{degrees}, and 80{degrees}C for approximately nine weeks before shock testing at 315 kilobars impact stress. Four sets of pins were heated to 50.2{degrees}C (125{degrees}F) for approximately two hours and then impacted at either 50 or 315 kilobars. Also, four sets of pins were aged at 60{degrees}C for nine weeks and then heated to 50.2{degrees}C before shock testing at 50 and 315 kilobars impact stress, respectively. Particle velocity measurements at the contact point between the stainless steel targets and TOAD pins were ...

British Library Electronic Table of Contents (United Kingdom)

Summary Objective- Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference. Design- This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea. Subjects and measurements- Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening...

International Nuclear Information System (INIS)

Alloys of zirconium are widely used in various core components of power reactors. Nuclear assemblies require high degree of reliability and integrity for performing in radiation and corrosive atmosphere. The hostile environments of reactor core and inaccessibility for repairs make it mandatory to select only those joining techniques which produce not only superior quality but are also amenable to NDT methods and such other techniques which ensure acceptable performance. The author has worked on various types of welding of zirconium alloys for different applications. Modern techniques in electron beam (EB) welding, resistance welding, GTAW welding and laser welding have been developed for joining Zr alloys components for different types of reactors. Many of these have been standardized and successfully used in production. Several advancements have been made in the welding technologies towards achieving high productivity and increased reliability with economy and adaptability. EB, laser, ...

Energy Technology Data Exchange (ETDEWEB)

The impingement of a fluid jet onto a surface has broad applications across many industries. Within the UK nuclear industry, during the final stages of fuel reprocessing, impinging fluid jets are utilised to mobilise settled sludge material within storage tanks and ponds in preparation for transfer and ultimate immobilisation through vitrification. Despite the extensive applications of impinging jets within the nuclear and other industries, the study of two-phase, solid loaded, impinging jets is limited, and generally restricted to computational modelling. Surprisingly, very little fundamental understanding of the turbulence structure within such fluid flows through experimental investigation is found within the literature. The physical modelling of impinging jet systems could successfully serve to aid computer model validation, determine operating requirements, evaluate plant throughput requirements, optimise process operations and support design. Within this project a method is ...

Energy Technology Data Exchange (ETDEWEB)

Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters. In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10{sup 6}n/cm{sup 2}-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3 1/2 dimensions (x,{integral}dy,t) where the 1/2 dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow channels, MAPLE-type nuclear fuel flow channels, and CANDU-type nuclear fuel flow channels are investigated. Measurements of flow ...

Energy Technology Data Exchange (ETDEWEB)

The Segmented Rail Phased Induction Motor (SERAPHIM) is a compact, pulsed linear induction motor (LIM) offering a unique capability for very high speed train propulsion. It uses technology developed for the Sandia coilgun, an electromagnetic launcher designed to accelerate projectiles to several kilometers per second. Both aluminum cylinders and plates were accelerated to a kilometer per second (Mach 3) by passing through a sequence of coils which were energized at the appropriate time. Although this technology was developed for ultra-high velocity, it can be readily adapted to train propulsion for which, at sea level, the power required to overcome air resistance limits the operational speed to a more modest 300 mph. Here, the geometry is reversed. The coils are on the vehicle and the ``projectiles`` are fixed along the roadbed. SERAPHIM operates not by embedding flux in a conductor, but by excluding it. In this propulsion scheme, pairs of ...

UK PubMed Central (United Kingdom)

PurposeUltrasonically measured intravesical prostatic protrusion may be a promising noninvasive method of assessing bladder outlet obstruction. Previous investigations...Full Text Available

International Nuclear Information System (INIS)

Ultrasonic and eddy-current techniques are used to automatically examine large diameter tubular products during their production for defective areas and out-of-tolerance conditions.

Science.gov (United States)

The purpose of this study was to develop a simple motion measurement system with magnetic resonance (MR) compatibility and safety. The motion measurement system proposed here can measure 5-DoF motion signals without deteriorating the MR images, and it has no effect on the intense and homogeneous main magnetic field, the temporal-gradient magnetic field (which varies rapidly with time), the transceiver radio frequency (RF) coil, and the RF pulse during MR data acquisition. A three-axis accelerometer and a two-axis gyroscope were used to measure 5-DoF motion signals, and Velcro was used to attach a sensor module to a finger or wrist. To minimize the interference between the MR imaging system and the motion measurement system, nonmagnetic materials were used for all electric circuit components in an MR shield room. To remove the effect of RF pulse, an amplifier, modulation circuit, and power supply were located in a shielded case, which was made ...

International Nuclear Information System (INIS)

It is shown that low-frequency elastic vibrations of near-surface planar defects cause high-frequency ultrasonic radiation in surrounding air. The frequency conversion mechanism is concerned with contact nonlinearity of the defect vibrations and provides efficient generation of air-coupled higher-order ultraharmonics, ultrasubharmonics, and combination frequencies. The nonlinear air-coupled ultrasonic emission is applied for location and high-resolution imaging of damage-induced defects in a variety of solid materials.

Science.gov (United States)

PMID:19862292

Energy Technology Data Exchange (ETDEWEB)

The Control Rod Drive(CRD) nozzles for PWR nuclear power plants(NPP) house the control rod drives. The number of nozzle penetrations range from the mid-30's to over 100 in each reactor head. The integrity of CRD nozzles is very important, because the primary pressure boundary is established with the J-groove weld joining the nozzle to the head clad surface. The Alloy 600 PWSC CRD nozzle leaks discovered in the fall of 2000 and spring of 2001 in several US plants. Therefore the NRC has recommended a more proactive effort by US utilities to inspect similarly susceptible nozzles in all US plants. The primary safety concern is circumferential cracks that can permit the nozzles to separate from the head at high velocity and produce a large-break leak in the reactor vessel. A secondary concern is head leakage from any through-wall cracks in the nozzle or J-groove weld area. Numerous inspection and repair tools have been developed to address CRD nozzle inspection ...

Science.gov (United States)

One of the least understood regions of the upper atmosphere is the thermosphere, principally due to the difficulty of making observations. The neutral atmosphere is known to be highly variable, and its composition and density varies by several orders of magnitude due to solar activity, diurnal cycles, latitude, geomagnetic activity, and gravity waves. In the past, most in-situ measurements of the neutral atmosphere have utilized detectors that are dependent on arrival angle and energy accommodation of incoming species, so that information related to nascent velocity distribution and reactive species abundances is often masked. This paper will review design concepts and laboratory tests related to the development of a novel open-ionizer, neutral particle detector for space environment measurements which can overcome these limitations. The sensor features a very large field-of-view suitable for sounding rocket missions. This time-of-flight instrument uses ...

Energy Technology Data Exchange (ETDEWEB)

Since microwaves are used in human cancer therapy, information on specific biological effects of microwaves at elevated temperatures is important. To help supply this information, we exposed mammalian cells (CHO) and bacteria (Serratia marcescens) to hyperthermal temperatures (43, 44, and 45/sup o/C for CHO and 48, 49, and 50/sup o/C for the bacteria) with and without microwave irradiation. Temperature control was maintained by a refrigeration-reheat system and high-velocity water recirculation. The 2450-MHz microwave source was operated in a pulsed mode with power density up to 500 mW/cm/sup 2/. As expected, the survival curve slopes for both cell types increased rapidly with temperature, doubling for each degree Celsius. Microwave irradiation produced no significant change in extrapolation number for either cell type. However, survival curves of CHO cells which received microwaves were steeper by a factor of 1.25 than their sham-irradiated ...

Science.gov (United States)

... the vertical beam measures the movement of the ... be measured because the particle velocity in ... During precipitation, if the hydrometeor fall velocity is ...

UK PubMed Central (United Kingdom)

An improved method of counting acoustic emission (AE) events from water-stressed stems of cedar (Thuja occidentalis L.) is presented. Amplified AEs are analyzed on a real time basis...Full Text Available

International Nuclear Information System (INIS)

In this paper the authors show the means putting in place for examination of steam generators tubes. These means (eddy current probes, ultrasonic testing) associated with a knowledge on degradation phenomena allow mapping controlled tubes and limiting undesirable obturations.

Energy Technology Data Exchange (ETDEWEB)

Although ultrasonic testing inspection technology and tools have improved significantly, there is still a need for more reliable detection, monitoring, and accurate sizing of crack-like and planar defects, complex corrosion damage, and detection of secondary features within deformed pipe. Ultrasonic two dimensional (2D) matrix phased array technology offers some unique advantages that make the technology promising for improving detection and sizing of pipeline flaws resulting from welding or from in-service damage. Ultrasonic modeling and simulation has been conducted to evaluate the detection and sizing capabilities of 2D matrix arrays for various pipeline inspection concepts. Simulations have been performed using both flexible and rigid array probes. Inspection concepts using rigid probes were evaluated for inspections from both the outside and inside pipe surfaces, while flexible probes were evaluated primarily for ...

Environmental Research Database

ObjectivesObjectives Not AvailableDescriptionTo determine the effects of water penetration on the burst strength of filament wound composite pipes which have been damaged by impact and then subjected to long term pressurisation with sea water. ~%~ To monitor and characterise the damage and effects of sea water penetration using ultrasonic NDT. To determine the burst strength of bonded composite pipe joints with and without defects and to see whether the defects can be detected using ultrasonic NDT. [continued...

Energy Technology Data Exchange (ETDEWEB)

Specificity of the pulses mean frequency measurement (the pulses being generated in a stochastic process) is described. Status of the domain of analog frequency meters is presented. Methods of increasing accuracy of such meters are discussed.

Science.gov (United States)

A univibrator and a pulse height discriminator using tunnel diodes and backward diodes are described, along with their applications in pulse shaping and fast coincidence technique. The main advantages achieved are simplicity of design and speed. The characteristics of the two diodes are shown. (auth)

CERN Document Server

Development of High Field Dipole and High Current Pulse Power Supply for Compact Proton Synchrotron

Science.gov (United States)

A Pulsed Radiation Dosimetry System designed to measure radiation produced by particle accelerators is described. The problems associated with total-dose measurement of irregular shaped pulses of ionizing radiation have been simplified. The system responds to extremely narrow pulses of charged particles or X-rays using a pin diode as the detector. Direct readout of dose in rads (Si) is displayed on a 3-1/2 digit digital panel meter. The system will operate in either the multiple-pulse or single-pulse mode. The multiple-pulse mode would be useful in monitoring or tuning a linear accelerator. In the single-pulse mode the system will automatically display total dose of a transient event in real time and hold that measurement indefinitely or until the next measurement is made. The system features an automatic reset in either mode.

UK PubMed Central (United Kingdom)

The torque-velocity relationship is known to be affected by ageing, decreasing its protective role in the prevention of falls. Interindividual variability in this torque-velocity relationship is partly...Full Text Available

Science.gov (United States)

and propels the projectile to a velocity sufficient to reach ..... CLF3 + N2 4 .... 5 inches or greater accelerates a finned projectile to the veloc ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes a technique for implementing the ultrasonic inside diameter (ID) creeping wave technique for detection and sizing ID connected defects using a phased array ultrasonic system. The technique uses multiple focal laws to produce the examination modes. The first focal law is designed to create a shear wave nominally at the critical angle for mode conversion to a longitudinal wave at the ID of a part, thus creating a creeping wave. This focal law is focused at the ID to improve sensitivity. The rest of the laws are designed to create tandem sound paths that progress up a vertical surface directly above the focal point of the creeping wave generation point. When a defect on the inner surface is detected with the creeping wave, the height of the defect can be measured from the response of a set of tandem laws without readjusting the position of the probe. Results from standard one-inch long notches of varying depths are presented.

Energy Technology Data Exchange (ETDEWEB)

After October 1993, Swedish BWR power plant operators will be required to present an inspection concept which will facilitate the nondestructive examination of recirculation system piping. According to the pertinent Swedish codes and standards, such inspections will be required to focus on internal pipe surfaces. Since it is impossible for external inspections to cover all essential areas with the necessary degree of sensitivity (geometry, beam attenuation), Siemens-KWU was commissioned to develop an inspection system which combines ultrasonic search units and eddy current probes to produce the required degree of examination sensitivity. A pipe crawler was developed to transport the inspection unit. This device can be used for the inspection of circumferential and longitudinal pipe welds, nozzle-to-pipe welds and RPV nozzle-to-shell welds. Special probes designed to fulfill inspection and manipulation requirements were developed for the inspection of the 30 welds ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

Free-electron laser (FEL) amplifiers have demonstrated high efficiencies and high output power at microwave wavelengths. However, measurements and simulations have indicated that the present level of phase stability for these devices is not sufficient for driving linear accelerators. Fluctuations in the diode voltage, which is needed to accelerate the electron beam, are the largest cause of the shifts in the phase of the output power. Pulse-power technology cannot keep the voltage fluctuations less than 1/4%. However, we have found a scheme that will make the output phase much less sensitive to these fluctuations by exploiting the traveling wave nature of the FEL interaction. In this paper we study the phase stability issue by analyzing the dispersion relation for an axial FEL, in which the rf field is transversely wiggled and the electron trajectories are purely longitudinal. The advantage of using the axial FEL interaction instead of the common transverse FEL ...

Energy Technology Data Exchange (ETDEWEB)

The object and the purpose of the present work was to develop, to assemble and to start running a new TOF (time of flight) mass spectrometer for imaging SNMS analytic which is optimized for the analysis of highly molecular secondary ions. The most important purpose was the characterization of the TOF mass spectrometer. The obtained mass spectra of indium, tantalum and silver clusters reflect the excellent properties of the TOF mass spectrometer for the detection of large clusters with good detection efficiency up to masses of 16000 amu. The possibility of the deflection of selected saturated atom and cluster peaks serves for further improvement of the detection efficiency for large molecules. The accessible mass resolution was determined to be of the order of m/{delta}m=1000 in the high mass region. Numerous measurements were carried out to characterize the useful yield of this spectrometer. For a best possible adaptation of the TOF mass spectrometer for the detection of highly ...

Energy Technology Data Exchange (ETDEWEB)

New Non Destructive Testing techniques are currently being developed for the inspection of two groups of components in the FA3 EPR nuclear reactor at Flamanville. The first group of components to be controlled is constituted by the welds of the (89) rod cluster control assemblies' containment; two control types are to be used: an ultrasonic technique (UT) evaluation from the outside of the flange-casing weld, and an ET control from the inside of the three other welds. The second group of components is formed by the 44 welded joints of the primary circuit, which will be inspected through ultrasonic testing. Details of the components, control devices and sensors are given and some test results are presented

Energy Technology Data Exchange (ETDEWEB)

The ultrasonic inspection pig system was described as being under development. This system was said to adopt the unique wheel type ultrasonic sensor which does not need couplant. This pig was designed to detect external corrosion in long-distance pipelines without interruption of the gas service. The wall-thickness measurement performance test and the travel performance test of the inspection pig in the test line confirmed that these performances satisfied the development specifications. However, the effect induced by the inner surface properties of the pipe and the influence of the pipe`s performance over long distances and for a long period of time still needed to be verified in an actual gas pipeline, and while the pipeline was actually in service. Improvements to the prototype model of the inspection pig were expected to include combinations of inspection pigs, with increases in battery and memory capacities to permit them to cope with in ...

British Library Electronic Table of Contents (United Kingdom)

Ultrasonic gold and aluminum wire wedge bonding are widely used for electrical and signal interconnections of the integrated circuit chip packages. In this paper, based on the metallurgical theories and thermal aging test methods, the long-term thermal reliabilities of gold and aluminum wire wedge bonding on aluminum and Au/Ni/Cu pads, were investigated, respectively. At 200degreeC, the Au/Al bond interfaces evolved little when the storage time was less than 48h; with the aging time increasing, the interfacial intermetallic compounds (IMC) grew up from the pad (vertical growth); the primary compounds were Au5Al2 near the bond toe and heel, and Au2Al at the periphery. Then, the thickness of IMC was unchanged, and extended horizontally (lateral growth), Au5Al2 transformed into more stable Au...

International Nuclear Information System (INIS)

The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries

Science.gov (United States)

... Descriptors : *TERMINAL BALLISTICS, *WOUND BALLISTICS, VELOCITY, CONVERSION, REPRINTS, TISSUES(BIOLOGY), MANUFACTURING ...

International Nuclear Information System (INIS)

We investigate the effects of the velocity-dependent force on the magnetic form factors and magnetic moments of odd-Z nuclei. The form factors are calculated with the harmonic-oscillator wavefunctions. It is found that the contributions of the velocity-dependent force manifest themselves in the very large momentum transfer region (q?4 fm-1). In the low and medium q region the contributions of the velocity-dependent force are very small compared with those without this force. However, in the high-q region the contributions of the velocity-dependent force are larger than the normal form factors. The diffraction structures beyond the existing experimental data are found after the contributions of the velocity-dependent force are included. The formula of the correction to the single particle magnetic moment due to the velocity-dependent force is reproduced exactly ...

Energy Technology Data Exchange (ETDEWEB)

The double-mode cepheid Y Car has been found to have a variable centre-of-mass velocity. Though the observations did not cover a cycle, an orbital period of about 400-600 days was estimated. Radial-velocity observations of this star have now been continued in order to derive the orbital elements. Observations were made with the photoelectric radial-velocity spectrophotometer at the coude focus of the 1.88-m reflector at Sutherland. The velocity system was standardized by frequent nightly observations of stars in the Mount Wilson catalogue with 'a'-quality radial velocities.

DEFF Research Database (Denmark)

BACKGROUND AND AIM OF THE STUDY: Abnormal flow conditions across aortic bioprosthetic valves may result in degenerative processes. Thus, it is important to implant biological valve prostheses with velocity profiles similar to those of native valves. The study aim was to compare blood velocity and velocity gradient profiles downstream of stented and stentless aortic valves implanted in pigs, and in native porcine valves. METHODS: Stented valve prostheses (Mitroflow, n = 7) or stentless valve prostheses (Solo, n = 5 or Toronto SPV, n = 7) were implanted into pigs; the native valve was retained in eight animals. After weaning the animals from cardiopulmonary bypass, cardiac magnetic resonance imaging was performed to determine the blood velocities and velocity gradient profiles. RESULTS: The native valves had a significantly lower peakvelocity (92 +/- 26 cm/s) than the artificial ...

Energy Technology Data Exchange (ETDEWEB)

Relativistic electron beams are used for generating high power microwaves. These microwave sources require electron beam generators spanning significant ranges in voltage and impedance. The pulsed power technology used to generate these electron beams is presented. Electron beam generators that produce beams with pulse durations in the 10-ns to 100-ns regime consist of an energy-storage section, pulse-shaping section, and an electron beam diode. The energy-storage section is either a Marx generator or capacitor bank-pulsed transformer. The pulse shaping is done with high-voltage transmission lines. The electron beam diode is usually a cold-cathode, space-charge-limited flow device. For longer pulses (/approximately/1 ..mu..s) the energy storage and pulse chaping can be combined. Lumped-element pulse-forming networks ...

Energy Technology Data Exchange (ETDEWEB)

The proton therapy gives an irradiation adapted to the shape and the depth of tumors ( eyes, head and neck) with a millimetric, even sub millimetric precision for the ophthalmological tumors. It is equally an excellent tool for the pediatrics tumors. For numerous treatments in France the proton therapy is associated to the photons treatments (x radiation). however, others physical treatments could modulate the medical offer, such thermal therapy or treatments by ultrasonic waves. (N.C.)

Science.gov (United States)

University research group with research areas: * Land based and submersible autonomous robots, (UUVs: AUVs and ROVs); * Controllers, electronics, sensor design and fusion, motion control; * Guidance and navigation of underwater vehicles; * AI, neural networks, fuzzy logic, subsumption control, behaviour based control; * Optical fibre and ultrasonic sensors for proximal object detection; * Robot arm control, visual servoing; * Imaging sonar applications; * Simulator development: UUV simulator; imaging sonar simulator; Aircraft/flight simulator.

Energy Technology Data Exchange (ETDEWEB)

In addition to their use in high-speed ovens, microwaves are also finding applications in industrial manufacture, quality control and storage - anywhere where the high-frequency transmission or reflection properties of a material can be exploited. Microwaves are also being used in medical applications for the characterization of certain type of tumours. They are also being used in research into ultrasonic cavitation. (authors) 5 refs.

Science.gov (United States)

An instrument has been constructed for the measurement of residual stress in steel. If necessary, large objects can be examined in situ. An account is given of the principles and construction. A special stressing frame provides for calibration. An application to residual stress in gear blanks has established a systematic variation of surface stress with nickel content and confirmed the overall effect of the surface hardening treatment.

International Nuclear Information System (INIS)

The time and dose characteristics of the electron and X-ray radiations of a tube, connected to a subnanosecond mega volt accelerator, are measured. By the pulse of the accelerating voltage of #>=# 600 kV with duration of #approx =# 0.3 ns the tube generates approximately 5 x 10"1"2 electrons pulse. The current amplitude equals approximately 5 kA/pulse and the radiation dose-about 5 kGy/pulse. The X-ray radiation dose from the tantalum external target constitutes 0.15 Gy/pulse. The prototypes of the electron and X-ray tubes sufficiently lower volumes, opening new applications in the technique and medicine, are developed

Energy Technology Data Exchange (ETDEWEB)

In the process of backward Raman amplification (BRA), the leading layers of the seed laser pulse can shadow the rear layers, thus weakening the effective seeding power and affecting parameters of output pulses in BRA. We study this effect numerically and also analytically by approximating the pumped pulse by the ''*-pulse'' manifold of self-similar solutions. We determine how the pumped pulse projection moves within the *-pulse manifold, and describe quantitatively the effective seeding power evolution. Our results extend the quantitative theory of BRA to regimes where the effective seeding power varies substantially during the amplification. These results might be of broader interest, since the basic equations, are general equations for resonant 3-wave interactions.

Energy Technology Data Exchange (ETDEWEB)

An electronically controllable apparatus is described which modulates a continuous wave laser beam so as to produce an output beam consisting of coherent ''pulses'' that are electronically controllable as to both pulse repetition rate and pulse width. The apparatus includes two acoustic devices positioned so that the laser beam passes through them in sequence, and apparatus or for passing sound waves through the devices to frequency shift the laser radiation as well as to diffract it. Each acoustic device such as generates sound waves containing a group of frequencies which result in spaced pulses. The spreading of a laser beam at which emanates from the first acoustic device is countered by the second acoustic device to produce a collimated, coherently pulsed, laser beam.

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the research conducted during Budget Period One on the project ''Improved Natural Gas Storage Well Remediation''. The project team consisted of Furness-Newburge, Inc., the technology developer; TechSavants, Inc., the technology validator; and Nicor Technologies, Inc., the technology user. The overall objectives for the project were: (1) To develop, fabricate and test prototype laboratory devices using sonication and underwater plasma to remove scale from natural gas storage well piping and perforations; (2) To modify the laboratory devices into units capable of being used downhole; (3) To test the capability of the downhole units to remove scale in an observation well at a natural gas storage field; (4) To modify (if necessary) and field harden the units and then test the units in two pressurized injection/withdrawal gas storage wells; and (5) To prepare the project's final report. This report covers activities ...

International Nuclear Information System (INIS)

A system for real-time neutron radiography of moving objects is described. It comprise a source adapted to generate a continuous uninterrupted series of neutron pulses. Each pulse has a predetermined peak power and duration compatible with the framing times of a real-time video imaging system. A transporter moves an object to be examined to bring sequentially position selected portions of the object in the path of the pulses. Where the object itself has moving components, pulses are sequentially incident on the object. According to any dissimilarities, the object will alter the intensity of the neutrons passing therethrough. In order to record separately the changes in the neutron intensity, for each pulse, an imager is positioned to receive the neutron beam pulses which have been altered by their passage through the object and produce images indicating ...

International Nuclear Information System (INIS)

We have studied both theoretically and experimentally a new scheme of active pulse compression in a free electron laser (FEL) amplifier. The pulse compression scheme presented here is the following. A frequency-chirped pulse is injected into the FEL interaction region. Because of the high gain and narrow bandwidth of the FEL interaction, only the resonant frequency band of the pulse is actively amplified, resulting in a short pulse of high power coherent radiation at the output of the laser. For our experimental parameters (beam voltage #approx =# 150 kV, current #approx =# 5.0 A, wiggler period #approx =# 3.5 cm and gain #approx =# 10 dB), pulses of a few nanoseconds were generated at #approx =# 10 GHz after an interaction length of 2.30 m, in good agreement with theoretical expectations. For the same input pulses (width > 100 ns, ...

Energy Technology Data Exchange (ETDEWEB)

The essential mechanical and electronic parts of a beam pulsing system are described, which reaches an energy resolution of ..delta..E/E=0.1%-0.4% in the energy range from 100 eV and 10 keV.

Energy Technology Data Exchange (ETDEWEB)

This progress report presents a detailed description of the background, technology and application, and Statement of Work for the development of a coal-fired pulse combustor for residential space heating.

International Nuclear Information System (INIS)

An optical klystron is built in the 800 MeV electron storage ring at University of Science and Technology of China for harmonic super-radiation generation. In single bunch operation mode the repetition rate of the spontaneous radiation pulses is about 4.533 MHz, and the repetition rate of the seed laser pulses is about 3 Hz, while the radiation pulse duration is 300 ps. For measuring harmonic radiation a high on/off ratio ICCD is used as an optical switch to reject spontaneous radiation pulses of high repetition rate

Environmental Research Database

No further description is available

International Nuclear Information System (INIS)

We report on the collision of 1.5 ps (FWHM) laser pulses traversing at 17 a short similar 7 ps (FWHM) 46.6 GeV electron bunch. The phase-locked system used to maintain the correct timing of the laser pulses and the appropriate diagnostics are described. The jitter between the laser and electron pulses is determined from the stability of the observed rate of Compton scatters and can be described by a Gaussian distribution with #sigma#_j#approx =#2.2 ps. (orig.).

Science.gov (United States)

... pulses by a 50/50 beamsplitter and recombined in space and in time inside a wafer of KDP crystal which generates a second harmonic of the ...

Science.gov (United States)

... This is achieved by the use of a unique logic circuit employing a plurality of flip-flop devices, multivibrators and AND gates. ...

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

Compton backscattering of laser photons near the interaction point of an e"+e"- or e"-e"- collider can be used to produce a #gamma#-#gamma# or #gamma#-e"- collider. This paper describes the laser requirements, including pulse duration, intensity, energy, and wavelength, for such a collider. For most of the proposed, next generation, e"+e"- colliders, the laser wavelength should be in the near-infrared, with a pulse duration of 1 ps or less and an energy of similar 1 J per pulse. Current chirped pulse amplification laser systems in solid state lasing materials are well suited to meet these requirements. These systems are described. ((orig.)).

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

In this paper, model analysis into the time-dependent transmembrane potential at the outer cell membrane is presented, for applied high-intensity electric pulses having durations in the nanosecond range or smaller. It is argued that the frequency-dependent dielectric response of cell membranes could be used to advantage for stronger bioeffects by employing shorter pulses. Our model calculations predict faster transmembrane voltages and larger electroporation densities for a given external energy with pulse durations in the subnanosecond regime. This temporal regime would be used, for example, in the electrotherapy of mixed cell ensembles having different dielectric response properties. PMID:21937300

Science.gov (United States)

in pulse applications such as magnetic forming. ... In magnetic-forming electric circuitry, the ..... Aspects of Electrohydraulic land Magnetic Forming. ...

Energy Technology Data Exchange (ETDEWEB)

Computer simulations and experiments indicate that we can shape the infrared picosecond pulses of the Mark III FEL in amplitude, frequency, and phase. Strongly modulated fundamental and second harmonic pulses have been generated by operating the Mark III FEL in the regime of strong sideband growth. In this paper, we present the results of simulations and experiments for second harmonic generation with fundamental inputs from 2 to 3 {mu}m.

Science.gov (United States)

The mz8310 device support module provides support for the following record types: event, pulseCounter, pulseDelay, and pulseTrain. No driver support is needed. Up to 4 mz8310 modules are supported. Each 8310 module contains 10 channels, which are identified as signals O,...9. Each channel is individually configurable. Each mz83 10 has two Am9513 Timing Controller chips. Each Am9513 has 5 counters.

UK PubMed Central (United Kingdom)

We have previously shown that unloaded shortening velocity (V₀) of human plantar flexors can be determined in vivo, by applying the “slack test”...Full Text Available

Science.gov (United States)

The results of an experimental study of axial and crossflow velocity in a 7-pin wire wrapped bundle similar for FFTF fuel bundles are reported. The results are compared with the forced crossflow model of the COBRA-III C computer program. (JWR)

Science.gov (United States)

... at the end of this report. A. Low-Velocity Impact of Composite Sandwich Panels In 2007, the PI developed analytical solutions ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Changes in transverse phonon sound velocity were measured during low temperature irradiation of amorphous Pd{sub 80}Si{sub 20} with 3.5 MeV krypton ions. The sound velocity decreases as a function of the ion fluence and shows a tendency to saturate at large fluences at a relative change of {minus}4.7%. The changes in sound velocity were used to determine the changes in shear elastic constant and in Debye temperature both of which were in reasonable agreement with the value reported in the literature.

Energy Technology Data Exchange (ETDEWEB)

Time resolved light scattering from laser-induced electrostrictive gratings was used for the determination of flow velocities in air at room temperature. By measuring the velocity profile across the width of a slit nozzle we demonstrated the high spatial resolution (about 200 mm) of this novel technique. (author) 3 figs., 1 ref.

Energy Technology Data Exchange (ETDEWEB)

Qualifying corrosion inhibitors for use in high velocity multiphase flowlines in arctic or subsea environments is discussed. The tests include high velocity flow loop corrosion tests, pumpability through 0.125 (0.318 cm) inch capillary at low temperatures, compatibility with Nylon 11, emulsion tendency testing, and partitioning characteristics. Laboratory and field data show the importance for using the above criteria for inhibitor selection.

International Nuclear Information System (INIS)

Recently a new method of controlling the pulse length of a short-pulse free-electron laser (FEL) has been developed. By modulating the synchronism between the optical and electron pulses in the FEL cavity, it was found that the output power and the micropulse length of the FEL beam oscillates at the modulation frequency. In this paper, we study theoretically the behavior of the micropulse length, both in the high loss (steady state) regime and the low loss (limit cycle) regime, when a modulated desynchronism is applied. In order to do this, we analyze the dynamics of a short-pulse FEL oscillator. The modulation frequency value plays an important role in the dynamics. We find that there is a resonantlike phenomenon between the externally applied desynchronism modulation and the limit cycle oscillation without modulation of a free-electron laser.

International Nuclear Information System (INIS)

The dynamic response of cylindrical and ring-shaped YBaCuO bulk parts to pulsed magnetic fields is calculated by using small sets of finite elements. Some comparisons with experimental results are provided, and they give confidence in the modelling of the superconducting properties. Transient magnetizations as a function of time and space as well as shapes and absolute values of trapped magnetic flux profiles are presented. The influence of the sample geometry is investigated for different millisecond pulsed magnetization processes. Results are reported for different radial thicknesses and heights, different pulse durations, peak magnetic fields and pulse sequences with and without stepwise cooling. Comparisons concerning the achievable trapped magnetic field and flux are made, and implications for the use of high-temperature superconductor bulk parts as cryo-permanent magnets in potential applications ...

Energy Technology Data Exchange (ETDEWEB)

Ultra-short-pulse reflectometry is studied by means of the numerical integration of a one-dimensional full-wave equation for ordinary modes propagating in a plasma. The numerical calculations illustrate the potential of using the reflection of ultra-short-pulse, microwaves as an effective probe of the density profile even in the presence of significant density fluctuations. The difference in time delays of differing frequency components of the microwaves can be used to deduce the density profile. The modification of the reflected pulses in the presence of density fluctuations is examined and can be understood based on considerations of Bragg resonance. A simple and effective profile-reconstruction algorithm using the zero-crossings of the reflected pulse and subsequent Abel inversion is demonstrated. The robustness of the profile reconstruction algorithm in the presence of a sufficiently small amplitude ...

Science.gov (United States)

Data fusion techniques are based on the premise that two or more carefully designed NDE tests are potentially capable of offering additional information concerning the test object relative to what can be garnered from a single test. However, information from a heterogeneous set of transducers cannot be fused unless the data is mapped onto a common `format'. The eddy current method cannot, for example, provide time-of-flight information that can be combined from estimates derived from ultrasonic tests. This paper presents a simple solution to address the problem by employing the so-called Q-transform to relate diffusive fields, such as those generated by eddy current probes, and propagating wave fields generated by ultrasonic NDT sensors. The paper illustrates how the distance between a defect and a source can be extracted from eddy current data generated using carefully selected excitation signals. Numerical results and comparisons with ...

International Nuclear Information System (INIS)

Fine ceramic particles of zirconia toughened alumina (ZTA), titania toughened alumina (TTA), and zirconia-titania toughened alumina (ZTTA) have been synthesized by ultrasonic spray pyrolysis (USP) at various temperatures from starting salt solutions of various compositions aiming for the development of catalytic material. These particles were characterized for properties such as shape, size and size distribution, diffraction pattern, and chemical and phase composition of elements by scanning electron microscopy (SEM), particle size analyzer (PSA), x-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Chemical compositions and sizes of ceramic composites have been controlled by the stoichiometry of salt solutions and the flow rate of spraying solutions. The optimum experimental conditions for the various composite particle synthesis have been proposed.

Energy Technology Data Exchange (ETDEWEB)

A porous tooling system was selected for the processing of Graphite/PMR-15 Polyimide laminates in thickness up to 3.2 mm. (0.125 inch). This tool system must have a reasonable strength, permeability dimensional stability, and thermal conductivity to accomplish curing at 600 F and 200 psi and 200 psi autoclave temperature and pressure. A permeability measuring apparatus was constructed and permeability vs. casting water level determined to produce tools at three different permeability levels. On these tools, laminates of 5, 11, and 22 plies (.027, .060, and 0.121 inch) were produced and evaluated by ultrasonic, mechanical, and thermal tests to determine the effect of the tool permeability on the cured laminates. All tools produced acceptable laminates at 5 and 11 plies but only the highest permeability produced acceptable clear ultrasonic C-Scans. Recommendations are made for future investigations of design geometry, and strengthening techniques ...

International Nuclear Information System (INIS)

The inspection of PFR evaporator tubing, superheater and reheater tubing, and tube plate examinations, are described. Ferritic steel U tubes in the evaporator have been examined by an eddy current system operating at 400 kHz using flexible rotating probes. Surface defects as shallow as 0.1 mm can be detected and sized in the range 0.1 to 0.5 mm deep. An ultrasonic method is under development for wall thickness. Special test coil probes have been developed for examination of the type 316 stainless steel superheater and reheater tubing. Crack-life defects in the bore are detectable at approximately 10% wall thickness and 20% on the outside diameter. Tube plate examinations from the tube holes, have been conducted using eddy current probes which identify surface breaking cracks in the holes. For detecting curtain cracks between tube plate holes, ultrasonic compression wave probes have been used. (U.K.).

Science.gov (United States)

A laser pyrolysis technique has been used to produce ultrafine particles of iron carbide with diameters ranging from 2 to 20 nm. Catalysis using iron carbide was investigated in the liquefaction of Wyodak subbituminous coal; yields were determined. A study was carried out to examine the possibility of using an ultrasonic extraction technique as a rapid method of product work-up of samples following pretreatment or liquefaction experiments. A similar study had shown that extraction of coal-derived products by an ultrasonic method was rapid and gave yields and product distributions comparable to those obtained by Soxhlet extraction. On another project, three different types of supported catalysts were used to test activity for the combined water-gas shift hydrogenation of a synthetic donor solvent. The three catalysts tested were: (1) Alumina supported NiMo catalyst-Shell 324m; (2) Bulk hydrous TiO NiMo catalyst; (3) Thin film hydrous TiO ...

CERN Document Server

This document is divided in two parts. The first part deals with the radial velocities (RV) distributions for B-type stars and nebulosities observed with the VLT-GIRAFFE in the Large and Small Magellanic Clouds towards the open clusters NGC2004 and NGC330. Thanks to the resolution of GIRAFFE spectra, we found that the RV distribution for the nebulosities in the LMC is bi-modal. This bi-modality can be interpreted, in term of dynamics, by the expansion of the LMC4 superbubble. The second part deals with the GAIA space mission and the determination of the radial velocities by using Radial Velocity Spectrometer (RVS) spectra. The methods to determine the radial velocities are presented as well as preliminary results on simulated RVS spectra.

Energy Technology Data Exchange (ETDEWEB)

The repeated use and limited lifetime of a composite tiring vessel compel a need to survey techniques for monitoring the structural integrity of the vessel in order to determine when it should be retired. Various nondestructive techniques were researched and evaluated based on their applicability to the vessel. The methods were visual inspection, liquid penetrant testing, magnetic particle testing, surface mounted strain gauges, thermal inspection, acoustic emission, ultrasonic testing, radiography, eddy current testing, and embedded fiber optic sensors. It was determined that embedded fiber optic sensor is the most promising technique due to their ability to be embedded within layers of composites and their immunity to electromagnetic interference.

International Nuclear Information System (INIS)

A preliminary investigation was completed on the characterization and decontamination of coral samples from Johnston Island. These samples were found to contain individual particles (2 to 0.25 mm) of contaminated coral as well as a piece of contaminated magnetic metal. They ranged in activity from about 70 to 811 nCi Am-241. The decontamination methods investigated were froth flotation, ferrite treatment, attrition scrubbing, ultrasonic treatment and dry sieving. Dry sieving, the more effective technique, separated about 42 wt % of the coral into a decontaminated fraction. This fraction (>4 mm) contained about 0.5% of the total activity. 7 refs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

This study deals with the application of wavelet analysis to detection and characterization of defects from eddy-current and ultrasonic testing signals of a low signal-to-noise ratio. Presented in this paper are the methods for processing eddy-current testing signals of heat exchanger tubes of a steam generator in a nuclear power plant. The results of processing eddy-current testing signals of tube test pieces with artificial flaws show that the flaw signals corrupted by noise and/or non-defect signals can be effectively detected and characterized by using the wavelet methods. (author)

Energy Technology Data Exchange (ETDEWEB)

The ion-velocity dependence of the ionization probability for an atom ejected from a surface is examined by using a quantum approach in which the coupled motion between electrons and the outgoing nucleus is followed along the whole trajectory by solving the stationary Schroedinger equation. We choose a very-small-cluster-model system in which the motion of the atom is restricted to one dimension, and with energy potential curves corresponding to the involved channels varying appreciably with the atom position. We found an exponential dependence on the inverse of the asymptotic ion velocity for high emission energies, and a smoother behavior with slight oscillations at low energies. These results are compared with those obtained within a dynamical-trajectory approximation using either a constant velocity equal to the asymptotic ionic value, or expressions for the velocity derived from the eikonal ...

Energy Technology Data Exchange (ETDEWEB)

The authors investigated the application of pulsed corona discharge process to the removal of SO{sub 2} and NO{sub x} from industrial flue gas of an ioron-ore sintering plant. This study was performed on a pilot scale, which is the most advanced demonstration of this process. The flow rate of 5000 m{sup 3}/h of the flue gas was successfully treated. The electrode structure of the corona reactor is the same with that of conventional electrostatic precipitator. The authors made use of magnetic pulse compression technology to produce repetitive high voltage pulse. Pulse width (full width at half maximum) was reduced to less than 1 {micro}s by connecting a resister in parallel with the corona reactor. An inductor was added to the resister in series to minimize the loss by restricting the current flowing through the resister. By this way, they were able to deliver pulse power with peak ...

International Nuclear Information System (INIS)

A high power Free-Electron Laser (FEL) has lased at a wavelength of 22 #mu#m at the Japan Atomic Energy Research Institute (JAERI). The maximum power on a macro-pulse average is 1.7 kW, and it corresponds to an FEL energy of 160 #mu#J/micro-pulse. Extraction efficiency from the electron beam to the FEL radiation was measured to be 5.3% by an energy analyzer, when the maximum FEL power was coupled out. The rms wavelength spread was measured to be 4.6% at the same time. The extraction efficiency, in general, has a maximum value near the zero detuning length of an optical cavity, where (in contrast) the single-pass gain becomes smallest. A high peak current and a long macro-pulse duration are therefore indispensable for realizing high efficiency. The electron beam energy is 16.5 MeV, and the average current is 5.3 mA at a micro-pulse repetition rate of 10.4 MHz. The macro-pulse ...

Energy Technology Data Exchange (ETDEWEB)

The US Department of Energy's Pittsburgh Energy Technology Center (PETC) is actively pursuing the development and testing of coal-fired combustion systems for residential, commercial, and industrial market sectors. In response, MTCI initiated the development of a new combustor technology based on the principle of pulse combustion under the sponsorship of PETC (Contract No. AC22-83PC60419). The initial pulse combustor development program was conducted in three phases (MTCI, Development of a Pulsed Coal Combustor Fired with CWM, Phase III Final Report, DOE Contract No. AC22-83PC60419, November 1986). Phase I included a review of the prior art in the area of pulse combustion and the development of pulse combustor design concepts. It led to the conclusion that pulse combustors offer technical and base-of-operation advantages over conventional burners and ...

Energy Technology Data Exchange (ETDEWEB)

A self-seeded free electron laser (FEL) provides a high gain and extraction efficiency for the emitted light. An accelerator outputs a beam of electron pulses to a permanent magnet wiggler having an input end for receiving the electron pulses and an output end for outputting light and the electron pulses. An optical feedback loop collects low power light in a small signal gain regime at the output end of said wiggler and returns the low power light to the input end of the wiggler while outputting high power light in a high signal gain regime.

International Nuclear Information System (INIS)

Measurements of low-energy (#approx#10"- "1"0 J) femtosecond laser pulse durations have been carried out on the basis of second-order autocorrelation function analysis. The scheme of non collinear second harmonic generation realized in KDP crystal has been used for increasing of the measurement contrast and accuracy. Proposed scheme can be used for measurements in wide enough ranges of laser pulse durations (from tens femto seconds to hundreds picoseconds) and energies. (authors)

Energy Technology Data Exchange (ETDEWEB)

There is increasing demand to functionalize meso- and nano-porous materials by coating and make the porous substrate biocompatible or environment friendly. However, coating on a meso-porous substrate poses great challenges, especially if the pore aspect ratio is high. In the current work the pulsed laser deposition (PLD) method is used for coating Ni{sub 3}Al-based meso-porous membranes with diamond-like carbon (DLC) layers of high thickness homogeneity and adhesion. (orig.)

Energy Technology Data Exchange (ETDEWEB)

A small, permanent-magnet insert structure for the removal of electrons from pulsed, extracted, negative ion beams has been developed at Lawrence Berkeley National Laboratory. The device was computer modeled and designed for an extraction field strength of 3 kV/mm. The testing was carried out with a rf driven multicusp ion source optimized for the production of H{sup {minus}} ions and pulsed at a few Hz with pulse widths of several hundreds of {mu}s. It is demonstrated that the insert structure together with a collar can remove over 98{percent} of electrons from the extracted H{sup {minus}} ion beam without any significant deterioration of the H{sup {minus}} ion output. Application to other negative ion beams can be expected from this magnetic collar insert. {copyright} {ital 1996 American Institute of Physics.}

Science.gov (United States)

... at compositions below -AlP 4 the films were still unstable, hydrolysing in room air, and the long term stability of higher aluminium phosphides is in ...

International Nuclear Information System (INIS)

This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N_2 : H_2) and pulsed ratio (pulse on/off time ratio).

Energy Technology Data Exchange (ETDEWEB)

To measure electron reactions on a picosecond timescale the investigators developed a picosecond pulse-conductivity technique, which makes use of the electron fine-structure pulses of our LINAC (pulse width 25 vs FWHM) to produce excess electrons and now detects changes in sample conductance under optimum conditions with an instrumental response of 18 ps. This resolution is in agreement with a theoretical estimate. This technique has been successfully applied to study excess electron reactions in solvents covering a mobility range from 0.24 to 100 cm/sup 2/V/sup -1/s/sup -1/; extension to lower mobility liquids seem possible.

Energy Technology Data Exchange (ETDEWEB)

A flowing carbon dioxide laser was operated at low pressures up to 4 torr. Excitation of the laser was provided using various combinations of direct current (DC), pulsed microwave, and continuous wave (CW) microwave excitation. The microwaves were in the 2.45 GHz band and were coupled into the gas using a slow-wave interdigital transmission line. Laser output of 25 milliwatts (mw) was achieved using a DC discharge only. A combination of a DC discharge and pulsed microwaves doubled the output and resulted in some modulation. Changing the laser gas mixture and pulsed microwave field characteristics allowed some flexibility in the modulation. Lasing was not achieved with excitation from the CW microwaves alone due to the formation of localized discharges. Using pulsed microwaves to sustain the discharge and CW microwaves to pump the laser, a quasi-CW output of 55 mw was achieved.

International Nuclear Information System (INIS)

Presented are the investigation results of electrophysical and physico-mechanical properties of KLF-20, Viksint U-4-21, Viksint KT-73, UF-7-21, KG-184, KL-4, KL-16SE-305, VIAT-1 and PPK-21 sealants, irradiated with sources of continuous and pulse #gamma#-radiation, as well as pulse #gamma#-neutron radiation. It is shown that electrophysical and physico-mechanical properties of sealants after irradiation by continuous #gamma#-radiation up to 10"6 doses and pulse gamma-neutron radiation with neutron fluence of 10"1"3 neutron/cm"2 and #gamma#-radiation dose of 10"4R do not practically change. Electric conductivity and tangent of the angle of dielectric losses increase in the process of irradiation. Electric conductivity depends on irradiation type, is proportional to dose rate and does not depend on temperature and pulse duration.

Energy Technology Data Exchange (ETDEWEB)

In the rf-driven free-electron laser (FEL) at the Los Alamos National Laboratory, there are two pulsed-power rf modulators as sources for two tandem, side-coupled 20-MeV linear accelerators. The rf power used to control the cavity fields is supplied by two 5.5-MW modulating anode klystrons operating at a center frequency of 1300.2 MHz. The modulation of the 125 kV klystron is achieved by using a triode switch tube that provides a pulse width up to 300 ..mu..s and a pulse repetition rate up to 10 Hz. This paper describes the present configuration of these two duplicate systems and presents plans for meeting the requirements of future rf FEL experiments at Los Alamos. 12 refs., 5 figs.

Energy Technology Data Exchange (ETDEWEB)

Recently there has been growth, in interest in non-equilibrium interaction of half-period long optical pulses with matter. To date the optical pulses have been produced by chopping out a half-period long segment from a longer pulse using a semiconductor switch driven by a femtosecond laser. In this paper we present new methods for producing tunable ultra-short optical pulses as short as half an optical period using a free-electron laser driven by electron bunches with a duration a fraction of an optical period. Two different methods relying on the production of coherent spontaneous emission will be described. In the first method we show that when a train of ultra-short optical pulses as short as one half period. We present calculations which show that the small signal gain is unimportant in the early stages of radiation build up in the cavity when the startup process is dominated by ...

British Library Electronic Table of Contents (United Kingdom)

Effect of Abdominal Active Can on DFTs. Introduction: Many patients with implantable cardioverter defibrillators (ICDs) have older lead systems, which are usually not replaced at the time of pulse generator replacement unless a malfunction is noted. Therefore, optimization of defibrillation with these lead systems is clinically important. The objective of this prospective study was to determine if an active abdominal pulse generator (Can) affects chronic defibrillation thresholds (DFTs) with a dual-coil, transvenous ICD lead system. Methods and Results: The study population consisted of 39 patients who presented for routine abdominal pulse generator replacement. Each patient underwent two assessments of DFT using a step-down protocol, with the order of testing randomized. The distal right ...

International Nuclear Information System (INIS)

Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)

Energy Technology Data Exchange (ETDEWEB)

The heating and current drive systems are being developed to support long pulse, high {beta}, advanced tokamak fusion physics experiments in the KSTAR tokamak. The heating and current drive systems consisting of neutral beam injection (NBI), ion cyclotron waves (ICRF), lower hybrid waves (LHCD) and electron cyclotron waves (ECH/ECCD) have been designed to operate for pulse lengths up to 300 sec and to provide a range of control functions including current drive and profile control. Development of key technologies for high power, long pulse operation has been on going. Substantial progress has been made on areas such as RF launchers, ion source, and high power supplies.

Science.gov (United States)

... is a standard in the utility industry which is used to study switching transients on power distribution networks and high-voltage transmission lines. ...

International Nuclear Information System (INIS)

During a Workshop on Gamma-Gamma Colliders in Lawrence Berkeley Laboratory, it was pointed out that an 1-#mu#m laser that can produce 1-J, 1-ps pulses at a few hundred hertz is required. With high-power scalability and ease of formatting, an FEL can be a promising candidate for such a laser. The authors propose an FEL scheme based on chirped-pulsed regenerative amplification to achieve this high peak-power laser. The 1-ps pulse of a solid-state laser will be stretched, amplified, and recompressed to achieve the high peak power. The system is relatively simple and consists of mostly components that have already been demonstrated. This paper will describe the proposal and the important issues of such a scheme.

Science.gov (United States)

... Multivibrators were used in the first model, which is called the "MV Model." Mwe second model, "1ST Model," has a saw-toothed voltage. ...

Energy Technology Data Exchange (ETDEWEB)

Due to the improvement of algorithm and the advancement of calculation performance, the imaging by depth migration before stacking is being put into practice from the viewpoint of both calculation cost and accuracy. A lot of imaging examples have been already reported from the survey areas with complicated velocity structures, such as the North Sea and the Gulf of Mexico. Effectiveness of the method has been confirmed. For imaging techniques in Japan National Oil Corporation and Japan Petroleum Exploration Co., Ltd., high-speed depth migration before stacking and high efficiency velocity structure estimation technique have been investigated. This paper describes necessary care to be taken when using depth focusing analysis (DFA) for correcting a velocity model, as an interim stage of case study. The results of depth migration before stacking using dip moveout (DMO) velocity were further inferior to the ...

Energy Technology Data Exchange (ETDEWEB)

Three popular imaging methods were used to carry out seismic migration from the Alberta foothills: Kirchhoff integral, reverse-time and explicit finite-difference migration methods. The imaging comparisons of reverse-time, Kirchhoff and f-x post-stack depth migration leads to the following conclusions. All of the three migration methods can provide acceptable and well-imaged intermediate results on the simplest model. Post-stack migration was not very sensitive to the accuracy of the velocity field once a reliable structural stack was available. With respect to the imaging accuracy and calculation cost, the Kirchhoff migration method seemed to be superior to reverse-time and f-x migration algorithms because its results on different kinds of velocity cases were basically kept coherent and consistent with the velocity model given by Mobil. Because of the lack of an accurate velocity field, reverse-time ...

CERN Document Server

The paper develops a new class of financial market models. These models are based on generalized telegraph processes: Markov random flows with alternating velocities and jumps occurring when the velocities are switching. While such markets may admit an arbitrage opportunity, the model under consideration is arbitrage-free and complete if directions of jumps in stock prices are in a certain correspondence with their velocity and interest rate behaviour. An analog of the Black-Scholes fundamental differential equation is derived, but, in contrast with the Black-Scholes model, this equation is hyperbolic. Explicit formulas for prices of European options are obtained using perfect and quantile hedging.

Energy Technology Data Exchange (ETDEWEB)

The velocity distribution of electrons ejected close to the forward direction by 0.8-2 MeV/A ions traversing various solid targets, including a Au monocrystal, is measured in coincidence with emerging charge-selected ions. The velocity spectrum is observed to be independent of outgoing projectile velocity and charge state for polycrystalline targets. Measurements on the Au crystal under channeling conditions show dependences on final charge state, and are tentatively explained by assuming that the main contribution to the production yield comes from the non-channeled fraction of the ions. A simple model for the creation of the forward-ejected electrons is proposed, which accounts for most of the experimental findings.

Scientific Electronic Library Online (English)

Abstract in english Numerical solutions for the effects of radiation on a MHD convective heat transfer past a semi-infinite porous plate with a magnetic field are obtained. It is assumed that the porous plate moves with a constant velocity in the direction of fluid flow, and the free stream velocity follows the exponentially increasing small perturbation law. The magnetic field acts perpendicular to the porous surface which absorbs the fluid with a suction velocity varying with time. The gov (more) erning equations for the flow are transformed into a system of nonlinear ordinary differential equations by perturbation technique and then are solved numerically by using the shooting method. The effects of the various parameters on the velocity, temperature profiles as well as the surface skin-friction and surface heat transfer are illustrated graphically.

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) ...

Energy Technology Data Exchange (ETDEWEB)

It is shown that plasma viscosity does not influence the magnetic island rotation directly. Nevertheless, it leads to nonstationarity of the plasma velocity. This nonstationarity is the reason of the viscosity effect on island rotation. (author)

Energy Technology Data Exchange (ETDEWEB)

This paper presents experimental data and an computational model of the cold spray solid particle impact process. Copper particles impacting onto a polished stainless steel substrate are examined. The high velocity impact causes significant plastic deformation of both the particle and the sub- strate, but no melting is observed. The plastic deformation exposes clean surfaces that, under the high impact pressures, result in significant bond strengths between the particle and substrate. Experimental measurements of the splat and crater sizes compare well with the numerical calculations. It is shown that the crater depth is significant and increases with impact velocity. However, the splat diameter is much less sensitive to the impact velocity. It is also shown that the geometric lengths of the splat and crater scale linearly with the diameter of the impacting particle. It is hoped that the results presented will allow better ...

Science.gov (United States)

Specialized tests can be designed to study impingement-corrosion, erosion- corrosion, cathodic protection systems, cavitation and other velocity effects. ...

International Nuclear Information System (INIS)

The detection efficiency of a lithium glass detector was calculated using MCNP code, and the calculation was compared with the published results in Pulsed Sphere Plan. A lithium glass detector of our own was made, and its neutron efficiency was calculated. The calculated neutron efficiency was verified with both pulsed and steady DD neutrons. Characteristics of Neutron response of "6Li detector was discussed. (authors)

CERN Document Server

We discuss optimal detection of fast radio transients from astrophysical objects while taking into account the effects of propagation through intervening ionized media, including dispersion, scattering and scintillation.Our analysis applies to the giant-pulse phenomenon exhibited by some pulsars, for which we show examples, and to radio pulses from other astrophysical sources, such as prompt radio emission from gamma-ray burst sources and modulated signals from extra-terrestrial civilizations.

International Nuclear Information System (INIS)

The author is exploring the efficiency of pulsed plasma processing in the removal of nitrogen dioxide, nitrogen oxide, and other pollutants. This process uses an electrical discharge to create chemical radicals from air molecules. These radicals can react with pollutants and form harmless compounds. Additives such as hydrocarbons are also used to improve the efficiency of the removal. The efficient removal of nitrogen dioxide has required the presence of dilute aqueous solution of ammonia.

International Nuclear Information System (INIS)

This paper summarizes a method to evaluate the possible effects of magnetohydrodynamic-electromagnetic pulse (MHD-EMP) on power systems. This method is based on the approach adapted to study the impact of geomagnetic storms on power systems. The paper highlights the similarities and differences between the two phenomena. Also presented are areas of concern which are anticipated from MHD-EMP on the overall system operation. 12 refs., 1 fig.

Energy Technology Data Exchange (ETDEWEB)

The paper presents a description of the physical processes governing the variations of the pulse rise-time which occur during the operation of the proportional counter and are due to varying either the count rate or the applied voltage. On the basis of the rise-time concept the differences in the count rate effect observed in various types of proportional counters are discussed.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the methods and systems as utilized in an integrated experimental thermohydraulic/mechanics analysis test program on waterhammer pressure pulses within a revised feedwater sparger of a Loviisa generation VVER-440-type reactor. This program was carried out in two stages: (1) measurements with a strictly limited set of operating parameters at Loviisa NPP, and (2) measurements with the full set of operating parameters on a test article simulating the revised feedwater sparger. The experiments at Loviisa NPS served as an invaluable source of information on the nature of waterhammer pressure pulses and structural responses. These tests thus helped to set the objectives and formulate the concept for series of tests on a test article to study the water hammer phenomena. The heavily instrumented full size test article of a steam generator feedwater sparger was placed within a pressure vessel simulating the steam generator. The ...

International Nuclear Information System (INIS)

An analytic solution is obtained for the equations of resonance coherent SRS by neglecting the population of the final level of the Raman transition for the systems with the active-medium length that is smaller than the wavelength of the incident light. For the extended systems, a numerical solution is obtained. The energy distribution of the Stokes pulses is found. The large-scale (about 100%) fluctuations of the Stokes radiation energy were observed in the case of unsaturated amplified spontaneous emission. (nonlinear optical phenomena)

International Nuclear Information System (INIS)

The TESLA Test Facility (TTF) at DESY is a facility producing sub-picosecond electron pulses for the generation of VUV or soft X-ray radiation in a free electron laser (FEL). The same electron pulses would also allow the direct production of high-power coherent radiation by passing the electron beam through an undulator. Intense, coherent far-infrared (FIR) undulator radiation can be produced from electron bunches at wavelengths longer than or equal to the bunch length. The source described in this paper provides, in the wavelength range 50-300 #mu#m, a train of about 1-10 ps long radiation pulses, with about 1 mJ of optical energy per pulse radiated into the central cone. The average output power can exceed 50 W. In this conceptual design, we intend to use a conventional electromagnetic undulator with a 60 cm period length and a maximum field of 1.5 T. The FIR source will use the spent electron beam ...

Energy Technology Data Exchange (ETDEWEB)

A novel approach is presented to extract relevant parameters associated with the energy loss of ejectiles from nuclear reactions obtained by digitizing the signals of a Bragg curve spectrometer. New and more powerful computational paradigms allow a more thorough pulse-shape analysis. This is fulfilled using a back-propagation artificial neural network as a pattern identifier. The known problem of over-training is discussed.

International Nuclear Information System (INIS)

In this paper, finite-difference time-domain method is used to research the transient electromagnetic pulse (EMP) coupling to the cylinder object which is shielded in another shielding cavity with a hole numerically. The different coupling effectiveness of three transient EMP is simulated. The distribution of the electric field in the shielding cavity and the current on the cavity are researched. The shielding effectiveness is evaluated. (authors)

British Library Electronic Table of Contents (United Kingdom)

The alloying of steel surface with aluminum (Al) using Microsecond-pulsed Intense Electron Beams (MIEB-Al) was developed and optimized in order to be used for improving the corrosion resistance of the 316, 1.4970 and T91 steels, exposed to liquid Pb and Pb-Bi-eutectic. The procedure consists in two steps: (i) coating the steel surface with Al or an Al-containing alloy layer and (ii) melting the coating layer and the steel surface layer using intense pulsed electron beam. In order to cover the steel surface with an homogeneous and crack-free Al-alloyed layer, the following experimental conditions are required: Al coating thickness range 5-10mm, electron kinetic energy 120keV; pulse duration 30ms; energy density 40-45J/cm2; number of pulses 2-3. Using the mentioned procedure, the corrosion r...

International Nuclear Information System (INIS)

In the microwave tokamak experiment (MTX) program, we are concentrating on experiments using intense, free-electron laser (FEL) generated microwave pulses. In initial FEL experiments, several diagnostic instruments were operated during injection of microwave pulses with peak powers to 0.2 GW at durations of 10 ns. Fixed and spatially scanning microwave detectors and receivers and a 48-element calorimeter on the inside wall of MTX diagnosed the GW-level FEL microwave pulses. With these diagnostics, linear-wave absorption and efficiencies of transmission through the quasi-optical transport system were studied. In addition, several radially resolved measurements of plasma density, temperature, and emission were made during FEL injection and were used in the analysis of microwave absorption data. A timing system, slaved to the FEL pulse arrival time, is capable of accuracy to a few nanoseconds in order to ...

International Nuclear Information System (INIS)

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO_2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona ...

International Nuclear Information System (INIS)

Computed tomography (CT) of the neck and mediastinum was performed in 16 patients with renal osteodystrophy. Thirty out of 34 excised parathyroid glands weighing more than 500mg were diagnosed preoperatively (88.2%). Scintigraphy of the neck with _2_0_1TlCl and sup(99m)TcOsub(4-) was also performed in 15 patients. The introduction of subtraction method with a mini-computor in the scintigraphy has remarkably improved the visualization rate of parathyroid glands. Ultrasonic echography (US) of the neck which is able to obtain not only transverse butalso longitudinal imaging was done in 7 patients. It has about same detection rate of the glands with CT. The visualization of enlarged parathyroid glands is valuable not only for localization but also for undeniable evidence of hyperparathyroidism. Also, repeated follow-up examination can determine the effectiveness of conservative treatment. (author).

British Library Electronic Table of Contents (United Kingdom)

N-doped TiO2 has been prepared by use of sol?gel systems containing titanium alkoxide, with nitric acid as the nitrogen source. The time needed for gelation of the systems was drastically reduced by ultrasonic irradiation. The peaks assigned to the nitrate and nitrous ions were observed by FT-IR measurement during the sol?gel reaction. The N-doping was confirmed by the observation of N?O peaks in the XPS spectrum of the sample heated at 400??C. The nitrate ion acted as an oxidizer of the ethanol solvent and titanium species. The TiO2 became doped with nitrogen oxide species as a result of reduction of nitrate ion incorporated into the dried gel samples. These results indicated that the added nitric acid was reduced during the sol?gel transition and heating process, and the resulting NO spe...

Energy Technology Data Exchange (ETDEWEB)

The objective of the inspection qualification is to ensure that applied non-destructive methods (NDT) have the required performance. The approach of the qualification process is systematic and carefully documented and therefore some new requirements can be seen concerning the composition of the documentation. There are also new document types, that only application of the inspection qualification requires. The most important of these is the technical justification, that includes the documented evidences concerning the performance of the inspection system. This publication includes two reports: 'Compilation of the inspection procedure' and 'Essential/influential parameters in NDT qualification'. The former of these discusses the issues to be considered in an inspection procedure especially from the point of view of the mechanised ultrasonic testing. The later report explains the parameters formulated to analyse in the technical ...

Science.gov (United States)

A 65-yr-old female developed cough, fever and dyspnoea following repeated exposure to a home ultrasonic humidifier. High-resolution computed tomography showed ground-glass opacity in both lung fields. Arterial blood gas analysis gave an oxygen tension of 8.38 kPa (63 Torr). Pulmonary function testing revealed restrictive ventilatory impairment with a reduction in the diffusing capacity. The diagnosis of extrinsic allergic alveolitis (EAA) was confirmed by radiographic findings, pathological evidence of alveolitis and reproductive development by a provocation test to the humidifier water. The yeast Debaryomyces Hansenii was the only microorganism cultured from the water of the humidifier. The double diffusion precipitating test and lymphocyte proliferative response was positive for an extract of D. Hansenii, providing evidence to incriminate this fungus. This is the first described case of EAA caused by D. Hansenii. PMID:12449192

International Nuclear Information System (INIS)

Dense samples of #beta#-sialons (with z from 1 to 4) were pressuressly sintered for different time (15-240 minutes) and at relatively low temperature of 1600 C using single-phase #beta#-sialon powders synthesized by combustion nitridation. The samples were characterized using ultrasonic method for determination of elastic properties (E,G,#mu#). Also, hardness by Knoop and fracture toughness by Vickers indentation microfracture method was estimated. With increasing z number Young's modulus decreases from 293 to 179 GPa. Simultaneously Poisson ratio increases by about 30%. The highest values of hardness and fracture toughness were obtained for sialon with z equal to 1. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Stoichiometric MgAl{sub 2}O{sub 4} spinel specimens irradiated in FFTF-MOTA at temperatures between 385 and 750C to fluences ranging from 2.2 to 24.9 {times} 10{sup 22}n cm{sup {minus}2} (E>0.1 MeV) darken significantly, but do not develop any significant loss in weight or change in dimensions. Similar behavior was observed in both single crystal and fully dense polycrystalline specimens. Measurements of elastic constants by an ultrasonic technique show that no measurable changes occur as a result of the irradiation. These and other results confirm the stability of this material for fusion application as an electrical insulator.

Energy Technology Data Exchange (ETDEWEB)

The ISI (In-Service Inspection) system has been developed so as to maintain the structural integrity of heat transfer tubes in the primary pressurized water cooler in the HTTR (High Temperature Engineering Test Reactor). This system consists of eddy current probes, ultra-sonic probes, insertion and extraction units, positioning unit and so on. Verification and performance tests of the developed ISI system were carried out using mock-up heat transfer tubes in the primary pressurized water cooler. The constitution of the system, R and D results of the inspection probes, and verification and performance test results of the ISI system for heat transfer tubes are described in this paper. (author)

Science.gov (United States)

The feasibility of this procedure was investigated using minerals and ore specimens. The substances were ground then fused using LiBO/sub 2/, quenched with 3% HNO/sub 3/ or mixtures of the acid with 2.5% tartaric acid or 30% H/sub 2/O/sub 2/. The quenched melt was usually completely dissolved within 20 min by placing the beakers in an ultrasonic bath. If any residue was detected, appropriate changes were made in the procedure. Once the procedure has been optimized, any remaining black particles were filtered. If these particles disappeared upon subsequent ignition, they were presumed to have been graphite. Most of the refractory minerals investigated should be expected to be converted to soluble form by this process. 1 table.

International Nuclear Information System (INIS)

This chapter consists of some points including an introduction, the basic parts of mass spectroscope device, sample introduction into the inductively coupled plasma, pneumatic nebuliser, ultrasonic nebuliser, dry gas cloud system, laser ablation unit, inductively coupled plasma-ion source, extraction of ions from ion source, mass analysis, quad-polar mass spectrometer, dual assembly mass spectrometer, mass spectrometer by calculation of time of flight, ion interferences and the ability of resolution, ion counter, working conditions of inductively coupled plasma mass spectroscope device, efficiency of ion transportation in an inductively coupled plasma mass spectroscope device and applications of analysis using mass spectroscope of induced plasma including nuclear, industrial, geological, environmental and archaeological applications, measurement of isotopes ratio and applications in tracing crimes.

International Nuclear Information System (INIS)

A transient flow reduction burnout experiment was conducted with water in a uniformly heated, vertically oriented tube. Test pressures ranged from 0.5 to 3.9 MPa. An analytical method was developed to obtain transient burnout conditions at the exit. A simple correlation to predict the deviation of the transient burnout mass velocity at the tube exit from the steady state mass velocity obtained as a function of steam-water density ratio and flow reduction rate. The correlation was also compared with the other data. (author).

Energy Technology Data Exchange (ETDEWEB)

The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation.

Energy Technology Data Exchange (ETDEWEB)

A possibility of generating collimated beams of faster-than-light particles (tachyons) and using them for rocket propulsion is explored. The relativistic rocket equations are derived, and are solved for a single-stage rocket with constant mass flow rate, constant exhaust velocity and no coasting period. The features of these solutions for faster-than-light exhaust velocities are discussed. It is shown that a tachyon drive would not violate the first law of thermodynamics. However, as seen in the Galactic frame, it would violate the second law.

Energy Technology Data Exchange (ETDEWEB)

The seismic reflection exploration technique which is one of the geophysical methods for oil exploration became effectively to image the subsurface structure with rapid development of computer. As a tool to perform seismic inversion, seismic forward modeling program using ray tracing should be developed. In this study, we have developed the algorithm that is to calculate the travel time of the complex geological structure using ray tracing by subdividing the geologic model into triangular element (finite element) having the constant velocity. We can analytically calculate Jacobian with some information by this current ray tracing. With this Jacobian, we will develop new algorithm which is to obtain geological properties and to image the subsurface. Since the FEM (Finite Element Method) ray tracing we have developed goes well the inverse velocities structure, we can apply the inversion problem to complex geological model. For the convenience of ...

International Nuclear Information System (INIS)

During the 2007 Niigataken Chuetsu-oki earthquake, strong ground motion with the peak acceleration of 680 cm/s/s which was larger than that of the empirical prediction was recorded at the base mat of the No.1 reactor building of Kashiwazaki-Kariwa Nuclear Power Station (NPS). Furthermore, in the Kashiwazaki-Kariwa NPS, over twice difference of 680 vs. 322 cm/s/s of peak acceleration between the No.1 and the No.6 reactor buildings was observed on the base mat. From the results of recent research, it is suggested that the deep sedimentary layers can be one of the important factors to elucidate these phenomena. In this study, at first, the applicability of microtremor array measurements for estimation of deep S-wave velocity structure (#approx#Vs=3 km/s layer) are discussed. Vertical microtremors were observed in three arrays at the Kashiwazaki-Kariwa NPS with the maximum station spacings of 3.04 km, 1.49 km and 0.75 km, respectively. The Rayleigh wave phase ...

Energy Technology Data Exchange (ETDEWEB)

Three instruments for measuring local velocities in liquid-metal MHD experiments for fusion blanket applications are being evaluated. The devices are used in room-temperature NaK experiments to measure three-dimensional flow field patterns anticipated in complex blanket geometries. Hot film anemometry, a standard technique in ordinary fluids, is being used, as well as two developmental devices. One is called the Liquid Metal Electromagnetic Velocity Instrument (LEVI), and performs essentially as a local dc electromagnetic flow meter. The third device, a Thermal Transient Anemometer (TTA) is a rugged, yet relatively simple device, which measures local velocity through the mechanism of convective heat transfer, in some ways similar to hot-film anemometry. Results are presented showing the kinds of data collected this far with each instrument. Measurements include both local velocity measurements and some ...

International Nuclear Information System (INIS)

A commercial CFD code, Fluent, has been used to analyse the design of a filter-press reactor operating with characteristic linear flow velocities between 0.024 and 0.192 m s-1. Electrolyte flow through the reactor channel was numerically calculated using a finite volume approach to solve the Navier-Stokes equations. The length of the channel was divided into 7 sections corresponding to distances of 0, 0.01, 0.04, 0.08, 0.12, 0.14 and 0.15 m from the electrode edge nearest to the inlet. The depth of the channel was divided into three planes parallel to the channel bottom. For each channel section, a velocity profile was obtained at each depth together with the average velocity in each plane. The flow predictions show that the flow development, as the electrolyte passes through the cell, is strongly affected by the manifold causing strong vortex structures at the entrance and exit of the channel. Although the flow ...

Energy Technology Data Exchange (ETDEWEB)

The two-dimensional Eulerian hydrodynamic code 2DE, with the shock initiation of heterogeneous explosive burn model called Forest Fire, is used to model numerically the interaction of jets of steel, copper, tantalum, aluminum, and water with steel, water, and explosive targets. The calculated and experimental critical condition for propagating detonation may be described by the Held V/sup 2/d expression (jet velocity squared times the jet diameter). In PBX 9502, jets initiate an overdriven detonation smaller than the critical diameter, which either fails or enlarges to greater than the critical diameter while the overdriven detonation decays to the C-J state. In PBX 9404, the jet initiates a detonation that propagates only if it is maintained by the jet for an interval sufficient to establish a stable curved detonation front. The calculated penetration velocities into explosives, initiated by a low-velocity jet, are ...

Energy Technology Data Exchange (ETDEWEB)

Fault analysis is required in addition to the ordinary process of structural analysis (CDP stacking) for the examination of discontinuity in the reflection horizon in question. The fault shape restoration principle is that the reflection point of a reflection wave observed at a certain receiving point is on an ellipse with the shock point and receiving point at its focal points and that the sum of the distances between the reflection point and the focal points is equal to the reflection wave propagation time. The DMO velocity is worked out by calculation using the positive travel time and inverse travel time from the common reflection surface. When the reflection surface is inclined by {theta}, the average interval velocity/cos{theta} is called the DMO velocity. When the reflection surface inclination and the average interval velocities are determined separately in this way, the position of the ...

Energy Technology Data Exchange (ETDEWEB)

A feasibility study test and 3 field trials were performed at Darlington NGS in 1996, 1999 and 2000 on ABB LP turbines. The scope of these trials was to commission in-situ automatic phased array systems capable to inspect blade roots and rotor steeples of L-0 and L-1 rows. GE disk-blade rim attachments were inspected at Bruce B nuclear station, in fall of 1999. The automated ultrasonic phased array technology is capable of high-speed rate and reliable detection and sizing. The capability demonstration was performed on mock-ups and reference blocks, using EDM notches. A custom built UT simulation software: Imagine 3D interfaces with SimScan to generates the spreadsheets/charts with target and probe coordinates and ultrasonic path and angles (refracted and skew) to hit the reference target. Examination of L-0 blade and rotor steeple grooves was performed with 2 phased array systems under networking. Data analysis was done in near-real time. ...

British Library Electronic Table of Contents (United Kingdom)

Pulses are rich in nutrients. The existence of anti-nutritional components and the length of time required for preparation have, however, limited their frequency of use compared to recommended intake levels. Anti-nutritional components in pulses can be largely removed by heat treatment. Additionally pre-treatment of pulses with heat and processing of seeds into flour could further enhance their use by decreasing processing and preparation times. In this study, trypsin inhibitor activity, functional properties, and microstructural characteristics of flours prepared from different varieties of lentil, chickpea, and pea as affected by roasting and boiling were evaluated. Both thermal treatments resulted in significant reduction (p<0.05) in trypsin inhibitor activity ranging from -95.6% to -37...

Energy Technology Data Exchange (ETDEWEB)

The production of retrograde amnesia (RA) upon electron-beam exposure was investigated. RA production was evaluated using a single-trial avoidance task for 10, 1, and 0.1 microsecond pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 1,000,000 rad/sec. By employing a 10 rad (1,000,000 rad/s) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory system activation which provided a novel stimulus that masked previous stimuli.

Energy Technology Data Exchange (ETDEWEB)

The Pulsed Lepton Source (PLS) project opens some exciting possibilities for muon and neutrino physics . The PLS would use the 0.25 4s proton pulses from the upgraded Proton Storage Ring (PSR) at LAMPF to create short, intense bursts of muons and neutrinos. The neutrino beam would be used for a few fundamentally important weak interaction physics experiments. The muon beams would find a wide variety of applications in both fundamental and applied'' muon physics areas. After a brief discussion of the physical layouts of the PSR and the proposed PLS in Sec. 2 and muon area in Sec. 3, we note some of the muon physics experiments and areas that could advantageously be addressed at the PLS in Secs. 4 and 5, and conclude in Sec. 6.

International Nuclear Information System (INIS)

Conductive TiN/Si_3N_4 ceramic composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity were investigated. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si_3N_4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. The electrode wear rate of brass is higher than copper electrode for all EDMed tests. The surface texture was found to have greater dependence on pulse energy. It was observed that the sinker-EDM at higher pulse energy caused severe microdamage in the surface. The surface roughness (Ra) values also increase with increasing pulse energy.

CERN Document Server

The nature of the `inner engine' that accelerate and collimate the relativistic flow at the cores of GRBs is the most interesting current puzzle concerning GRBs. Numerical simulations have shown that the internal shocks' light curve reflects the activity of this inner engine. Using a simple analytic toy model we clarify the relations between the observed $ \\gamma $-rays light curve and the inner engine's activity and the dependence of the light curves on the inner engine's parameters. This simple model also explains the observed similarity between the observed distributions of pulses widths and the intervals between pulses and the correlation between the width of a pulse and the length of the preceding interval. Our analysis suggests that the variability in the wind's Lorentz factors arises due to a modulation of the mass injected into a constant energy flow.

Energy Technology Data Exchange (ETDEWEB)

A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (~;;10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10^13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

Energy Technology Data Exchange (ETDEWEB)

A pillbox RF output window was developed for the L-band pulsed klystron for the Japanese Hadron Project (JHP) 1-GeV proton linac. The window was designed to withstand a peak RF power of 6 MW, where the pulse width is 600 {mu}sec and the repetition rate is 50 Hz. A high power model was fabricated using an alumina ceramic which has a low loss tangent of 2.5x10{sup -5}. A high power test was successfully performed up to a 113 kW RF average power with a 4 MW peak power, a 565 {mu}sec pulse width and a 50 Hz repetition rate. By extrapolating the data of this high power test, the temperature rise of the ceramic is estimated low enough at the full RF power of 6 MW. Thus this RF window is expected to satisfy the specifications of the L-band Klystron. (author).

British Library Electronic Table of Contents (United Kingdom)

The design and operating principle of a small (50 mm in diameter and 100 mm in height) ???-73C vacuum spark gap are described. It is shown that it can be efficiently switched using a control circuit with a low (?900 V) supply voltage, which is based on an inductive energy storage and a diode opening switch that forms a high-voltage igniting pulse with a rise time of nanosecond duration. The ???-73C switching process is investigated at different rise times of igniting voltage pulses and different igniting current amplitudes. The results of tests of the spark gap operating in regimes of switching current pulses with an amplitude of 12 kA and a rise time of 800 ns are presented.

Energy Technology Data Exchange (ETDEWEB)

One of the main challenges for a high energy {gamma}{gamma} collider is the high repetition rate required for the laser-electron-beam collisions to convert into high energy gamma beams. State-of-the-art, high power lasers have a much lower repetition rate than that of the electron pulses. It is therefore highly desirable that the same laser pulse can be reused. As an example, for NLC where beams collide at 120 Hz, within each collision cycle there are 90 electron bunches separated by 1.4 ns between successive bunches. We show, by invoking a recently invented laser optical box, that the laser pulses can be reused for the entire train of bunches within each collision cycle. ((orig.)).

International Nuclear Information System (INIS)

A high sensitivity, high bandwidth, two-color interferometer (1064 and 532 nm) has been tested on the Hawk pulsed power generator at the Naval Research Laboratory. The phase resolution is 10"-"5 waves with a rise time of 3 ns, a new capability for diagnosing plasmas, and neutrals in pulsed power experiments. The two-color feature is used to distinguish phase shifts from free (plasma) electrons and bound (neutral and ion) electrons. Simultaneous electron and neutral density measurements were demonstrated in a plasma opening switch (POS) experiment. The ability to measure small phase shifts with fast rise time were demonstrated in a plasma filled diode experiment. The high sensitivity and vibration isolation enable neutral gas distribution measurements from supersonic nozzles used in plasma radiation source experiments. Examples of these measurements and future applications are described. copyright 1997 American Institute of Physics.

Energy Technology Data Exchange (ETDEWEB)

Two-phase flow in horizontal parallel channels has been experimentally investigated under fuel cell related operating conditions. Pronounced hysteresis is observed in the pressure drop versus flow characteristic curve when starting from either flooded or dry conditions. When gas is introduced into channels initially filled with water (flooded initial condition), both gas and liquid tend to flow predominantly in one channel at low gas or liquid flow velocities. As the gas flow velocity increases, even distribution of gas and liquid flow in both channels is observed, accompanied with a sudden decrease in the pressure drop. On the other hand, even gas and liquid flow distribution between both channels is found at comparatively lower gas flow velocities when starting with dry-gas flow conditions with liquid introduced into channels filled with gas (stratified flow regime). The flow regimes of this system are visualized in plots ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this thesis is to study the behaviour of the simultaneous flow of oil and water in horizontal pipes. In this connection, two test facilities are used. Both facilities have horizontal test sections with inner pipe diameters equal to 2 inches. The largest facility, called the model oil facility, has reservoirs of 1 m{sub 3} of each medium enabling flow rates as high as 30 m{sub 3}/h, which corresponds to mixture velocities as high as 3.35 m/s. The flow rates of oil and water can be varied individually producing different flow patterns according to variations in mixture velocity and input water cut. Two main classes of flows are seen, stratified and dispersed. In this facility, the main focus has been on stratified flows. Pressure drops and local phase fractions are measured for a large number of flow conditions. Among the instruments used are differential pressure transmitters and a traversing gamma densitometer, respectively. The ...

British Library Electronic Table of Contents (United Kingdom)

Abstract In this paper, the effect of several turbulence parameters during various flow conditions in Owens Valley, educed from coherent Doppler lidar data have been studied. Radial velocity structure functions are processed to estimate the turbulent kinetic energy (TKE) dissipation rate, integral length scale and velocity variance, assuming a theoretical model for isotropic wind fields. Corrections for turbulence measurements have been considered to address the complications due to inherent volumetric averaging of radial velocity over each range gate, noise of the lidar data, and the assumptions required to estimate effects of smaller scales of motion on turbulence quantities. Using data from the Terrain-induced Rotor Experiment (T-REX) in April-May 2006, vertical profiles of wind and tur...

Energy Technology Data Exchange (ETDEWEB)

The unsteady two-dimensional laminar flow of a viscous incompressible electrically conducting micro polar fluid via a porous medium past a semi-infinite vertical porous moving plate in the presence of a transverse magnetic field is studied. A uniform magnetic field acts perpendicularly to the porous surface in which absorbs the micro polar fluid with a suction velocity varying with time. The effects of material parameters on the velocity and temperature fields across the boundary layer are investigated. The method of solution can be applied for small perturbation approximation. Numerical results of velocity and temperature distributions of micro polar fluids are compared with the corresponding flow problems for a Newtonian fluid. (author)

Energy Technology Data Exchange (ETDEWEB)

The space derivation term of a wave equation is accurately calculated using Fourier transform method, and the wave equation only relating to time derivative in time-space domain is derived. Solving this equation with the aid of central difference method brings the numerical recursion formula for forward modeling or reverse time migration of seismic wave field in the medium in which seismic velocity varies. The key to this method lies in introducing two auxiliary wave fields relating to velocity and spacial frequency of Fourier transform respectively after multi-dimensional Fourier transform respectively after multi-dimensional Fourier transform of space vector is made. Theoretically, this method is suitable to the forward modeling and migration of seismic wave field in complex area where seismic velocity and structure shape vary arbitrarily. Theoretical results proved this method satisfactory.

Energy Technology Data Exchange (ETDEWEB)

Specimens of glassy Pd{sub 80}Si{sub 20} were irradiated at temperatures below 100K with 3.5 MeV krypton ions. After irradiation, changes in the sound velocity were measured at 80 K without warm-up by Brillouin scattering. The sound velocity decreased with increasing ion fluence and exponentially approached a saturation value of -4.7%. The change in the shear elastic modulus per unit concentration n of defects was estimated to be d(ln C)/dn = -9.4 to -4.7. The results of the present study are compared with changes in the elastic properties predicted recently by an interstitialcy model for glassy metals, and with the elastic properties of glassy metals after thermal treatment.

CERN Document Server

We present high-resolution hydrodynamical simulations of the degree and direction of polarisation imprinted on the CMB by the Sunyaev-Zel'dovich effect in the the line of sight to massive galaxy clusters. We focus on two contributions which contribute most of the induced CMB polarisation in addition to the intrinsic CMB quadrupole: the radiation quadrupole seen by electrons due to their own velocity in the plane normal to the line of sight, and the radiation quadrupole due to the thermal Sunyaev-Zel'dovich effect, which is generated by a previous scattering elsewhere in the cores of the local and nearby clusters. We show that inside the virial radius of a massive cluster, this latter effect, although being second order in the optical depth, can reach the level of the former effect. These two effects can, respectively, constrain the projected tangential velocity and inner density profile of the gas, if they can be separated with multi-frequency ...

Science.gov (United States)

Mixed convection in a rectangular channel (width/height = 2) with bottom-heated and top-cooled sections is studied by laser Doppler anemometry in nitrogen at Ra = 22,200 and Re = 18.75, 36, and 54. At the lower Re values, symmetry breaking is observed in steady but spatially oscillating flows that prevail over a certain distance from the leading edge of the differentially heated section. Further downstream, unsteady flows are found even for Re = 18.75. Numerical models are used to investigate the effects of adiabatic, conducting (with a conductive-convective heat transfer coefficient), and perfectly conducting side walls; channel tilts and Prandtl number dependence. Good agreement between calculations and experiment is obtained for longitudinal convective roll velocities. The transverse velocities are found to be independent of Re.

Energy Technology Data Exchange (ETDEWEB)