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Kelvin-Helmholtz instability of short gravity waves is examined in order to explain the recent findings of the decrease in momentum transfer from hurricane winds to sea waves. A three-fluid configuration of a foam layer between the atmosphere and the ocean is suggested to provide signifficant stabilization of the system and shifting the marginal critical wavelength to the shortwave part of the spectrum. It is conjectured that such stabilization leads to the observed drag reduction. The high contrasts in three fluid densities provide a universal mechanism for stabilizing surface perturbations.

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Understanding the processes responsible for coastal change is important for managing our coastal resources, both natural and economic. The current scientific understanding of coastal sediment transport and geology suggests that examining coastal processes at regional scales can lead to significant insight into how the coastal zone evolves. To better identify the significant processes affecting our coastlines and how those processes create coastal change we developed a Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System, which is comprised of the Model Coupling Toolkit to exchange data fields between the ocean model ROMS, the atmosphere model WRF, the wave model SWAN, and the sediment capabilities of the Community Sediment Transport Model. This formulation builds upon ...

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The present paper is concerned with the prediction method for the motions and tensions of mooring lines on slack-moored floating oceanic architectural building in coastal zone. The motions and the tensions of mooring lines were estimated by the time domain numerical simulation in the present method. The present method includes the nonlinearity of mooring system, slow varying wave drift force. The authors performed a time domain numerical simulation for motions and the tensions of mooring lines on floating barge in two component waves. Also, the results obtained by numerical simulation were compared with the experimental results. The validity of the present method was confirmed.

British Library Electronic Table of Contents (United Kingdom)

A parameterized surface wave-induced vertical mixing (B"v) is incorporated into the Modular Ocean Model version 4 (MOM4). A comparison of the two numerical experiments with and without B"v shows that B"v can significantly improve the upper-ocean (20-100m) simulation in summer. The simulated upper-ocean temperature errors are reduced in summer due to the surface wave-induced vertical diffusive heat flux. The non-breaking-wave-induced vertical mixing can increase the probability of the simulated SST biases between -1^oC and 1^oC from 64% to 76% in the Southern Hemisphere (60^oS-10^oS) in January, and from 66% to 75% in the Northern Hemisphere (10^oN-60^oN) in July. The averaged mixed layer depth (MLD) simulated by the MOM4 without B"v is 14.4m shallower than the observations in 10^oS-60^oS i...

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The improvement in the functions of the viscous flow calculation method VEGA-SHIP around a ship and the expansion of application range were described as the numerical flow simulation in ship and ocean engineering and at the same time application examples to the ocean engineering by the general-purpose flow simulation code FLOW-3D handling the non-steady flow with a free surface were introduced as the numerical simulation regarding such products as a water gate and a dam. In the VEGA-SHIP, water surface was handled as a fixed wall so that wave could not be calculated. Therefore, an algorithm for calculating wave on the water surface was added to the VEGA-SHIP and a calculation method simultaneously considering the creation of wave around the ship and viscosity was developed. The FLOW-3D was used to calculate the phenomenon where inside liquid moved greatly due to the oscillation of a ...

CERN Document Server

A simple analytical/numerical model has been developed for computing the evolution, over periods of up to a few hours, of the current and temperature profile in the upper layer of the ocean. The model is based upon conservation laws for heat and momentum, and employs an eddy diffusion parameterisation which is dependent on both the wind speed and the wind stress applied at the sea surface. Other parameters such as the bulk-skin surface temperature difference and CO$_2$ flux are determined by application of the Molecular Oceanic Boundary Layer Model (MOBLAM) of Schluessel and Soloviev. A similar model, for the current profile only, predicts a temporary increase in wave breaking intensity and decrease in wave height under conditions where the wind speed increases suddenly, such as, for example, during gusts and squalls. The model results are compared with measurements from the lagrangian Skin Depth ...

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This site explains how temperature, pressure, and salinity work together to determine the density of ocean water. The three density layers of the ocean are described by means of text description and a graphic illustration.

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CERN Document Server

The adjoint of an ocean general circulation model is used as a tool for investigating the causes of changes in ENSO SST indices. We identify adjoint Kelvin and Rossby waves in the sensitivities to sea level and wind stress at earlier times, which can be traced back for more than a year through western and weak eastern boundary reflections. Depending on the thermocline depth the first and second baroclinic modes are excited. The sensitivities to the heat flux and SST are local and decay in about a month. The sensitivities to the fluxes are converted into the influence of SST using the adjoint of a statistical atmosphere model. Focusing on SST perturbations in the index region itself, we recover, up to a scale factor, the delayed oscillator concept.

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Experiments were carried out to test the hypothesis that instantaneous daily rates of egg-larval mortality of Pacific herring were higher at two oil-exposed sites than at two other sites not so exposed. Results showed that egg-larval mortality was twice as great in the oil-exposed areas as in the two non-oiled areas. Larval growth rates were also severely affected; they were about half of those measured in populations from other areas of the north Pacific Ocean. A cautionary note was introduced to the effect that the differences in the egg-larval mortality between oiled and control sites may have been influenced by differences in egg dessication, predation, and wave scouring, hence these results should not be construed as conclusive evidence of oil spill damage. 40 refs., 6 figs.

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As part of a larger elastic numerical modeling project, we have been investigating how energy reflected from steeply dipping interfaces is recorded using typical multicomponent acquisition geometries. Specifically, we have been interpreting how rcflection events from the flanks of salt dome structures are distributed on 3C and 4C phones for vertical seismic profiles (VSPs) and ocean bottom seismic (OBS) or land surface surveys. The ultimate goal of this investigation is to improve the structural imaging of steeply dipping interfaces and eventually to evaluate the usc of the recorded elastic wavefield for fluid description near these interfaces. In the current work, we focus on a common assumption used when processing converted wave reflection seismic data that most PP energy is recorded on the vertical geophone and/or the hydrophone and that most PS energy is recorded on the horizontal geophones. This is a useful assumption when it is valid, ...

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The satellite ocean color data record spans multiple decades and, like most long-term satellite

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The Formerly Utilized Sites Remedial Action Program (FUSRAP) is to evaluate the radiological conditions at former MED-US AEC sites. Purpose of the Ocean FUSRAP program is to assess the feasibility of ocean disposal of FUSRAP waste which contains trace natural radioactive materials. This paper presents soil characterization information on the Middlesex, NJ, Sampling Plant site, and reports preliminary ocean dispersion calculations. (DLC)

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A series of speeches is presented which cover political aspects of ocean energy, legislation, the status of the DOE Ocean Energy Program, the Maritime Administration OTEC Support Program. Six workshop reports are given covering ocean energy technology and systems concepts, power systems concepts, environmental developments, energy transfer and utilization, construction and test capabilities, and industry development. (LEW)

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In the development of the man-made island siting technology of nuclear power plants, assessing the stability of the seawall against large ocean waves and earthquakes is indispensable. Concerning with the seismic stability of the seawall, prediction of the deformation like sliding and settlement of the seawall during earthquake including the armour units in front of the caisson becomes important factor. For this purpose, the authors have developed the two-dimensional DEM-FEM coupled analysis method (SEAWALL-2D) to predict the deformation of the seawall covered with the armour units during earthquake. In this method, movements of the armour units are calculated in DEM analysis part and deformation of the caisson, rubble moundsand seabed and back fill are calculated in FEM analysis part taking the nonlinearity of the soil materials based on the effective stress into account. Numerical simulations of dynamic centrifuge model tests of the seawall ...

Science.gov (United States)

period T. Also shown is the returned chirp from a specular reflector at ...... algorithms is a Brown (1977) model of the return waveform, which assumes a ...... Townsend, W.F., 1980: An initial assessment of the performance achieved by ...

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The Subseabed Disposal Program has recently completed a 30-day, 0.286-scale laboratory simulation of an In Situ Heat Transfer Experiment (ISHTE), scheduled for eventual deployment in the deep ocean 600 nautical miles north of Hawaii. 10 figures.

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Only half of the carbon dioxide produced by burning fossil fuels stays in the atmosphere. It is thought that the oceans absorb the rest. To understand the world's climate it is necessary to know how the atmosphere, ocean and biosphere interact.

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... 2009. Copyright belongs to the Marine Technology Society., The original document contains color images. 14. ABSTRACT ...

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''Climates of the Oceans'' deals with the atmosphere over the world oceans and provides a treatment not only of the climatic elements such as temperature, pressure, wind, precipitation etc., but also of the circulation of the atmosphere and its changes throughout the year. The connection between sea and overlying air is examined through studies of the water and heat balance. Numerous maps and tables illustrate the elements and their fluctuations over the water and on islands and coasts.

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The Eiric Raude offshore drilling rig is a powerful machine that is suitable for drilling in harsh environments in ultra deep water. It has a total drilling depth of 8,200 to 10,000 metres and an operational displacement of 53,400 mt. The rig complies with the regulatory regimes of Norway, the United Kingdom and Canada. The Eiric Raude has drilled 5 deepwater wells offshore eastern Canada, 1 well offshore Cuba, 1 well west of Shetland, and 3 offshore Norway. The environmental criteria for extreme weather conditions consider wave, current and wind forces. The general operational guidelines were discussed along with key areas for prevention of environmental impact, including emissions from well testing, air emissions from diesel engines, cooling water, bunkering operations, discharges from drilling, accidental discharges, drain water, and domestic sewage. It was noted that the zero discharge philosophy is the basis for all activities. The original design was meant to ...

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A nonneutral /sup 7/Li/sup +/ ion plasma is described in which ion Langmuir waves are observed for the first time. The properties of these waves near the Brillouin density limit are investigated.

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Federal regulators were set to vote on a plan to protect deep water corals and other sensitive fish habitats that will likely include a permanent ban on ...

UK PubMed Central (United Kingdom)

The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their...Full Text Available

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A Self-Powered Underwater Robot for Ocean Exploration and Beyond ... first unmanned underwater vehicle (UUV) that is completely powered by renewable energy . ...

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A strategy for the management of the disposal of low-level radioactive wastes into coastal zones and ocean waters has developed over the past three decades. While there has been a substantial increase in the number of international and required agreements there has also been a concomitant improvement in our understanding of the ocean and the processes at work within it. This has allowed more rigorous and reliable assessments to be made of the radiological consequences. With the continued development of basic guidelines of radiological protection by the International Commission on Radiological Protection (ICRP) methodologies have been formulated to derive the fundamental scientific requirement - the relationship between disposal or release rate to the ocean and the resultant radiation dose to exposed human populations.

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CHORS, SDSU. OCRT Meeting (Washington, D.C., 14-16 Apr 2004). HPLC Phytoplankton Pigment Measurements: Continuation of Climate Quality Data Records ...

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... 2008. Characterizing the relative contributions of large vessels to total ocean noise fields: a case study using the Gerry E. Studds Stellwagen Bank ...

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... COURSE ° TRAWLING SPEEDKNTRAWLING DISTANCENM TEMP. FISHING DEPTH FROM°CTO °C TE...

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... Mineral and Organic Matter in the Coastal and Near-Coastal Ocean. ... Personal Author(s) : Stavn, Robert H. ; Spiering, Bruce A. ; Gould, Richard W ...

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The wave function of the Bianchi type-IX universe with small anisotropy is calculated using the Hartle-Hawking prescription.

Wastenet

... Rachel has also studied Geological Oceanography at the School of Ocean and Earth Sciences, University of Wales, Bangor, including a year spent at the Institute of Oceanographic Sciences Deacon Laboratory, Surrey, as a student researcher for the British Mid-Ocean Ridge Initiative (BRIDGE). Rachel has authored the following 1 Working Papers: 2002 ecm-2002-05 Towards Integrated Catchment/Coastal Management: Science, Policy ...

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...ENSO Applications Center (PEAC) Institutional Affiliation: PEAC's core members are The National Oceanic and Atmospheric Administration - Office of Global Programs (NOAA/OGP) The NOAA National Weather Service - Pacific Region (NWS-PR), The University of Hawaii - School of Ocean and Earth Science and Technology UH/SOEST, The University of Guam - Water and Energy Research Institute (UOG/WERI), and a regional association of the USAPI Governments, the Pacific Basin ...

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Based on the wave equation theory, the authors use finite difference method to derive wave-field extrapolation formula, by which both wavefield modeling and migration can be made. The migration program VSP MIG that was developed using P-wave equation may be used to migrate both surface seismic data and VSP data. Besides, it may be applied to the migrations of P-wave data and P-SV wave data, in which case the original velocity model should be modified properly. The migrated image times for P-wave and P-SV wave respectively are absolutely equal. The migrations of upgoing P-wave and upgoing P-SV wave which have been separated can offer migrated P-wave section and migrated S-wave section. Thus, one can get more information than from simultaneous migration of ...

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The Formerly Utilized Sites Remedial Action Program (FUSRAP) of the Department of Energy is designed to identify and evaluate the radiological conditions at sites formerly used by the Corps of Engineers Manhattan Engineer District and the US Atomic Energy Commission. Where required, remedial action will be instituted to remove potential restrictions on the use of the sites due to residual low-level radioactive contamination. A total of 31 sites that may require remedial action has been identified. The purpose of the Ocean FUSRAP Program, which began in March 1981, is to assess the technical, environmental, and institutional feasibility of disposing, in the ocean and on the ocean floor, of FUSRAP soil and rubble which contains traces of natural radioactive materials. The initial focus has been on the Middlesex, New Jersey, Sampling Plant site and surrounding properties, which contain on the order of 100,000 metric tons of ...

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This paper reports on the first U.S. tanker converted to a floating production, storage, and offloading (FPSO) unit which takes up station in Gombe-Beta field off Gabon by Dec. 1. FPSO Ocean Producer will work under a 3 year, day rate contract let late in 1990 by Amoco-Gabon Bombe Marin co., a unit of Amoco Production Co. (OGJ, Dec. 24, 1990, p. 27). Gombe-Beta field is in the Atlantic Ocean about 70 miles south of Port Gentil, Gabon. Ocean Producer will be moored in 50 ft of water 3.7 miles off Gabon, with Bombe-Beta's unmanned production platform about 820 ft astern. The vessel will be held in position by a disconnectable, asymmetric, six point, spread mooring system, It is owned and operated by Oceaneering International Services Ltd. (OISL). Affiliate Oceaneering Production Systems (OPS) converted the 78,061 dwt oil tanker MT Baltimore Sea at a capital cost of $25 ...

British Library Electronic Table of Contents (United Kingdom)

Political leaders in numerous nations argue for an upper limit of the global average surface temperature of 2 K above the pre-industrial level, in order to attempt to avoid the most serious impacts of climate change. This paper analyzes what this limit implies in terms of radiative forcing, emissions pathways and abatement costs, for a range of assumptions on rate of ocean heat uptake and climate sensitivity. The primary aim is to analyze the importance of ocean heat uptake for radiative forcing pathways that temporarily overshoot the long-run stabilization forcing, yet keep the temperature increase at or below the 2 K limit. In order to generate such pathways, an integrated climate-economy model, MiMiC, is used, in which the emissions pathways generated represent the least-cost solution o...

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Spratly Islands, located in the southern part of the South China Sea (SCS), consist of more than 100 small islands, coral reefs and banks. Remote sensing is the only way to obtain a synoptic view of all of the islands in such a large area. It has been demonstrated that satellite synthetic aperture radar (SAR) imagery is a very powerful tool for monitoring meso-scale and small-scale ocean processes in a large area. In this study, satellite SAR images were used to study the ocean environment in the area of Spratly Islands. The aim was to understand the capability of satellite remote sensing to monitor ocean processes and provide information for future field studies. Two sets of high-resolution European Remote Sensing satellite (ERS)-2 SAR images over the entire Spratly Islands area were coll...

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Man's wastes are polluting the oceans from various sources and delivered by various routes. The result has been the loss of habitat and the irreversible altering of marine ecosystems. Development in the coastal zones and offshore activities that disrupt biologically sensitive areas have led to international negotiations to regulate these impacts and develop a law of the sea. Basic to international cooperation, however, is the need to develop answers to questions about the ecological consequences of development programs and the carrying capacity of the oceans. Current information does not demonstrate long-term global impacts, making it difficult to detect and predict incremental changes and causal relationships. Society needs to determine how much environmental damage it will accept and then to develop appropriate technology, such as biomonitoring. Society also needs to reexamine its positions on technology-based regulatory controls to ...

International Nuclear Information System (INIS)

The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg U/m3 in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific nonwoven fabric was used as the adsorbent packed in an adsorption cage 16 m2 in cross-sectional area and 16 cm in height. We submerged three adsorption cages in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The three adsorption cages consisted of stacks of 52 000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the nonwoven fabric was >1 kg in terms of yellow cake during a total submersion time of 240 days in the ocean.

International Nuclear Information System (INIS)

This report is devoted to the investigation of the influence of electron collisions and radial non-uniformity of plasma density on phase characteristics, spatial attenuation and wave field structure of slow symmetric electromagnetic waves that propagate along cylindrical waveguide structure. It has been shown that collision rate and radial non-uniformity of plasma density for various parameters of waveguide structure and dielectric affect essentially on the wave characteristics and consequently, on the parameters of gas discharge that is sustained by this wave. The results obtained are of large importance for the construction of the theory of gas discharges that are sustained by the surface electromagnetic waves.

Science.gov (United States)

of satellite, aircraft and ground-based observations. In ..... swarm traps by Utah Department of Food and Agriculture (DAF) personnel. Preliminary Results ..... the 150th anniversary of the book's publication and the 200th anniversary of Darwin's birth. ...... cold war submarine missions to find that Arctic Ocean ...

UK PubMed Central (United Kingdom)

Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundIt has been reported that the El Niño–Southern Oscillation (ENSO) influences the interannual variation of endemic cholera in Bangladesh. There is increased...Full Text Available

Science.gov (United States)

I was wondering if someone could please help me out with the steps involved to process MODIS L0 data to 250m res TSM data using a ...

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Computer programs have been developed to define the temperature increase which would be needed to bring deep-ocean water into density equilibrium with surface water for locations where data are available. A series of continuous-flow studies on phytoplankton blooms resulting from mixtures of 80 percent deep and 20 percent surface water in 2000-liter concrete culturing vessels (''reactors'') has been completed. A quantitative determination of nutrient utilization and flow through a combined primary and secondary trophic level system has been completed. This study utilized the clam Tapes semidecussata, fed from phytoplankton grown in 80 percent deep and 20 percent surface water. An analysis of the fate of the deep water discharged from a floating OTEC plant indicates that horizontal containment of the resulting deep water: surface water mixture is necessary if conditions optimal for open-sea mariculture are to obtain. The design of ...

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provides global ocean-surface wind fields with more structures than numerical weather prediction (Geophys. Res. Lett., Vol 25, No. 6, 761-764). The NSCAT data sets was produced...

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Foreward: Preface; Introduction; The natural science of global climate change; Land and water use; Coastal zones and oceans; Energy and industry; Energy and social systems; Technological change; and Sponsoring organizations, International Advisory Board, and project participants.

UK PubMed Central (United Kingdom)

Harmful algal blooms, caused by rapid growth and accumulation of certain microalgae in the ocean, pose considerable impacts on marine environments, aquatic industries and even public health. Here, we...Full Text Available

National Aeronautics and Space Administration (NASA)

One tiny marine plant makes life on Earth possible: phytoplankton. These microscopic photosynthetic drifters form the basis of the marine food web, they regulate carbon in the atmosphere, and are responsible for half of the photosynthesis that takes place on this planet.

UK PubMed Central (United Kingdom)

BackgroundOceans are iron-deficient and nutrient-poor environments. These conditions impart limitations on our understanding of and our ability to identify microorganisms from the...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Wavy interface morphology is observed in Magnetic Pulse Welding (MPW) similarly to that of the Explosion Welding process (EXW). It is recognized that interfacial waves are formed in a periodic manner and have well defined wavelength and amplitude. The phenomenon of wave formation in EXW has been subjected to extensive investigations in which empirical and numerical models have been published. In the present study, a wave formation mechanism for MPW is presented. This wave-creation mechanism was studied by evaluating the influence of sample geometry on wave morphology using stereoscopic optical microscopy. It was found that interfacial waves are formed in a Kelvin-Helmholtz instability mechanism. Reflected shock waves interact with the welding collision point at the weld interface, where in...

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The impact of the azimuthal wave refraction in the middle atmosphere on the distribution of gravity wave amplitudes, propagation azimuths, and other wave parameters is investigated using a numerical ray-tracing model of gravity wave propagation through a representative zonal mean reference model of geostrophic winds and temperature in the middle atmosphere. Simulations are first performed with only a single type of gravity wave to help explain some important effects which occur during the refraction process. Then, a multiray simulation is performed which traces a crude spectrum of waves from different altitudes through the atmosphere for every month of a climatological year. The simulated wave climatologies are compared with observations. 108 refs.

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... An explosive charge (exploding bridgewire (EBW) detonator) was used for the crosshole P-wave tests. For the crosshole S-wave tests a ...

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We write a space-time Feynman Path Integral representation for scattered wave fields from a weakly/compact supported anisotropic non-homogeneity. (author)

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A first-order one-way wave system has been created based on characteristic analysis of the acoustic wave system and optimization of the dispersion relation. The authors demonstrate that this system is equivalent to a third-order scalar partial-differential equation which, for a homogeneous medium, reduces to a form similar to the 45{degree} paraxial wave equation. This system describes accurately waves propagating in a 2D heterogeneous medium at angles up to 75{degree}. The one-way wave system representing downgoing waves is used for a modified reverse time migration method. As a wavefield extrapolator in migration, the downgoing wave system propagates the reflection events backwards to their reflectors without scattering at the discontinuities in the velocity model. Hence, images with amplitudes proportional to reflectivity can be obtained ...

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CERN Document Server

In the positive column of a neon glow discharge, two different types of ionization waves occur simultaneously. The low-dimensional chaos arising from the nonlinear interaction between the two waves is controlled by a continuous feedback technique. The control strategy is derived from the time-delayed autosynchronization method. Two spatially displaced points of observation are used to obtain the control information, using the propagation characteristics of the chaotic wave.

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British Library Electronic Table of Contents (United Kingdom)

Superstrong shock waves of multimegabar level generated during ablation of an aluminum surface by intense (<1 PW/cm2) femtosecond laser pulses have been detected by observing the propagation of a shock wave in air from the ablated surface to a broadband piezoelectric receiver. The estimated initial pressure and velocity of the shock wave (ablation plume) agree well with data obtained earlier by various methods for shock waves propagating inside ablated targets.

Science.gov (United States)

Observations are presented that link extratropical Rossby wave disturbances excited in the Southern Hemisphere subtropical jet to the initiation of convectively coupled Kelvin waves in the Pacific intertropical convergence zone (ITCZ) during austral winter. A baroclinic, zonal wavenumber 6, eastward-propagating Rossby wave train in the subtropical jet turns northeastward in the vicinity of Australia, inducing upper tropospheric divergence and vertical motion fields that spread equatorward and induce cloudiness anomalies in the Tropics. Lower tropospheric pressure surges excited from the extratropics also induce Kelvin wave-like geopotential height and temperature anomalies at the surface, providing additional lower tropospheric convergence and vertical motion forcing. The tropical outgoing longwave radiation (OLR) and circulation fields propagate eastward in tandem with the extratropical Rossby ...

International Nuclear Information System (INIS)

Electrostatic wave measurements from the Active Magnetospheric Particle Tracer Explorer Ion Release Module have been used to investigate the wave modes and their possible generation mechanisms in the Earth's bow shock and magnetosheath. It is demonstrated that electrostatic waves are present in the bow shock and magnetosheath with frequencies above the maximum frequency for Doppler-shifted ion acoustic waves, yet below the plasma frequency. Waves in this frequency range are tentatively identified as electron beam mode waves. Data from 45 bow shock crossings are then used to investigate possible correlations between the electrostatic wave properties and the near-shock plasma parameters. The most significant relationships found are anticorrelations with Alfven Mach number and electron beta. Mechanisms which might produce electron beams in the ...

Science.gov (United States)

Outgoing longwave radiation (OLR) and low-level wind fields in the Atlantic and Pacific Intertropical Convergence Zone (ITCZ) are dominated by variability on synoptic time scales primarily associated with convectively coupled easterly waves during boreal summer and fall. This study uses spectral filtering of observed OLR data to capture the convective variability coupled to Pacific easterly waves. Filtered OLR is then used to isolate easterly waves in winds, temperature and humidity fields from TAO/TRITON and TAO/EPIC buoys, radiosondes, and gridded reanalysis products. Our analysis shows that while some of the Pacific easterly waves originate in the Atlantic, most of the waves appear to form and strengthen within the Pacific. Pacific easterly waves have wavelengths of 3300-5500 km and phase speeds of 9-13 m s-1. A warm, moist boundary layer is observed ahead of ...

International Nuclear Information System (INIS)

The collision of the Earth with extra-terrestrial ice-volatile bodies is proposed as a mechanism to produce rapid changes in the geologic record. These bodies would be analogs of the ice satellites found for the Jovian planets and suspected for comets and certain low density bodies in the Asteroid belt. Five generic end-members are postulated: (1) water ice; (2) dry ice: carbon-carbon dioxide rich, (3) oceanic (chloride) ice; (4) sulfur-rich ice; (5) ammonia hydrate-rich ice; and (6) clathrate: methane-rich ice. Due to the volatile nature of these bodies, evidence for their impact with the Earth would be subtle and probably best reflected geochemically or in the fossil record. Actual boloids impacting the Earth may have a variable composition, generally some admixture with water ice. However for discussion purposes, only the effects of a dominant component will be treated. The general geological effects of such collisions, as a function of the dominant component ...

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 ...

International Nuclear Information System (INIS)

Gravitational waves are propagating fluctuations of gravitational fields, that is, '' ripples '' in space-time, generated mainly by moving massive bodies. These distortions of space-time travel with the speed of light. Every body in the path of such a wave feels a tidal gravitational force that acts perpendicular to the wave's direction of propagation; these forces change the distance between points, and the size of the changes is proportional to the distance between these points thus gravitational waves can be detected by devices which measure the induced length changes. The frequencies and the amplitudes of the waves are related to the motion of the masses involved. Thus, the analysis of gravitational waveforms allows us to learn about their source and, if there are more than two detectors involved in observation, to estimate the distance and position of their source on the sky. ...

British Library Electronic Table of Contents (United Kingdom)

Many of the world's coral reefs suffered high coral mortality during the 1998 ENSO, with the highest mortality in the western Indian Ocean (WIO). A meta-analysis of field data on change in coral cover across the 1998 ENSO event was conducted for 36 major reef areas in the WIO, and relationship of the change with the historical sea-surface temperature (SST) variability investigated. WIO reefs were categorized into three major SST groups of differing coral cover change. Cover change was negatively associated with standard deviation (SD) SST until about SD 2.3, with increasing flatness of the SST frequency distributions. It increased with further increase in SD as the SST distributions became strongly bimodal in the Arabian/Persian Gulf area. The study indicates that environmental resistance/...

International Nuclear Information System (INIS)

"1"2"9I global distribution due to biogeochemical cycle in environment reservoirs has been studied. It is shown that during the operation of nuclear fuel cycle facilities and at a modern level of the decontamination factor the "1"2"9I concentration in some natural media (soil, the Earth biosphere, ocean mixing layer) will increase by 4-5 orders. Recommended gradual increase of the decontamnation factor in time for conserving the "1"2"9I concentration level not exceeding one order in comparison with modern one is given. At that to the end fof the centary the decontamination factor must be of an order of 1x10"4 in the case of "1"2"9I intake to the ocean mixing layer and of 1x10"5 in the case of its intake to the atmosphere.

Energy Technology Data Exchange (ETDEWEB)

The Offshore Comet is a modern offshore drilling rig with a hydraulic-cylinder-actuated jacking (raising and lowering) system. Hydraulic-cylinder jacking provides a safe and efficient method for placing the rig at the desired height above the water and insuring that it can withstand the expected heavy loads imposed by machinery, supplies, and the ocean environment. The drilling rig consists of a steel-hulled barge that is floated to the site and then supported during drilling operations by four steel triangular-cross-section lattice legs. The legs are planted firmly on the ocean bottom by a procedure called preloading. Each leg with its integral footing weighs 657 tons. The barge with its deck load can weigh up to 9200 tons.

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to check up a GPS (global positioning system) impact on scientific research activities of the Geodetic Society of Japan. First, it is mentioned that the conventional geoid-based concept of 'gravity anomaly' should be changed to a new definition, according to the GPS-determined ellipsoidal height system. Secondly, the results of many experiments, which have been made to monitor ocean-plate motions relative to the Japanese island-arcs, demonstrate that GPS is a powerful tool for obtaining temporal changes in horizontal displacement induced by the plate motion. Therefore, it is suggested that terrestrial measurements, such as triangulation and long-range leveling, would be replaced by GPS measurements in near future. Moreover, it is pointed out that GPS geodesy should play an important role in monitoring secular sea level trend due to global warming of the atmosphere and ocean. 19 refs., 4 figs.

British Library Electronic Table of Contents (United Kingdom)

World demand for rare-earth elements and the metal yttrium?which are crucial for novel electronic equipment and green-energy technologies?is increasing rapidly. Several types of seafloor sediment harbour high concentrations of these elements. However, seafloor sediments have not been regarded as a rare-earth element and yttrium resource, because data on the spatial distribution of these deposits are insufficient. Here, we report measurements of the elemental composition of over 2,000 seafloor sediments, sampled at depth intervals of around one metre, at 78 sites that cover a large part of the Pacific Ocean. We show that deep-sea mud contains high concentrations of rare-earth elements and yttrium at numerous sites throughout the eastern South and central North Pacific. We estimate that an a...

CERN Multimedia

The experiment NA59: The "Quarter Wave Plate" is a "110" silicon crystal of 5 cm diameter and 10 cm long

UK PubMed Central (United Kingdom)

Approximately 400 people die from extreme heat each year in the United States, and the risk of heat waves may increase as a result of global climate change. Despite the risk of heat-related morbidity...Full Text Available

CERN Document Server

Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as $\\Omega_{\\rm GW}(f) \\propto f^3$ with an amplitude ...

Energy Technology Data Exchange (ETDEWEB)

A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

Science.gov (United States)

The previously unknown property of the optical speckle pattern reported. The interference of a speckle with the counterpropagating phase-conjugated (PC) speckle wave produces a randomly distributed ensemble of a twisted entities (ropes) surrounding optical vortex lines. These entities appear in a wide range of a randomly chosen speckle parameters inside the phase-conjugating mirrors regardless to an internal physical mechanism of the wave-front reversal. These numerically generated interference patterns are relevant to the Brillouin PC mirrors and to a four-wave mixing PC mirrors based upon laser trapped ultracold atomic cloud.

Science.gov (United States)

... CHANNELS, TWO PHASE FLOW, WAVES, IGNITERS, GAS FLOW, HOWITZERS, CARTRIDGE CASES, COMBUSTIBLE CARTRIDGE CASES. ...

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

Science.gov (United States)

A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control. Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted. The results show that the wave front decreases sharply during the corona discharge along the corona wire. The higher the amplitude of the applied pulse is, the more the amplitude of the wave front decreased. The wave attenuation responds in a lower corona discharge inversely. To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design.

International Nuclear Information System (INIS)

The wave equation for spin;1/2 tachyons is derived from the Dirac equation and the principle of relativity extended to superluminal Lorentz frames. From this wave equation and the Dirac equation infinite velocity spinor transformations are obtained. They yield bispinors of the plane-wave states of the tachyon, their interpretation and covariant orthogonality relations satisfied by them. The transformation properties of the bispinors under Lorentz transformation are discussed. The boundary conditions for the free propagator of wave functions of tachyons are obtained and the propagator is constructed. Then the covariant S-matrix for scattering from an electromagnetic field is derived. It is applied to the scattering of electron-tachyons from the Coulomb field.

CERN Document Server

It is shown that the direct Fourier synthesization of light beams allows one to create polarity-asymmetric waves, which are able, in the process of nonlinear interaction with a medium, to break its inversion symmetry. As a result, these "polar" waves may show the effect of optical rectification in nonlinear centrosymmetric media by generating light-induced dc electric polarization. At the same time, the waves of this type, due to their unusual symmetry properties, can be used for detecting the direction and sign of a dc electric field applied to the medium. The prospects of application of polar waves to data recording and processing are discussed.

Science.gov (United States)

... INTERIOR BALLISTICS, GRANULES, HOWITZERS, MECHANICAL WAVES, COMBUSTIBLE CARTRIDGE CASES, WEAPONS, SIMULATION. ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

(15 Dec 1974). United States Harmon, BN Freeman, AJ Ames

Energy Technology Data Exchange (ETDEWEB)

The e/sup -/..-->..e/sup -/(..nu..nu-bar) process in the field of a circularly polarized plane wave is studied in the framework of the Glashow-Weinberg-Salam model. General expressions for the probability of creation of neutrino pairs are obtained, and the case of a low-intensity wave is studied in detail. The effects of asymmetry of emission of electron and muon neutrinos are estimated, and comparison with previous results is performed.

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus is provided for detecting explosives by thermal imaging. The explosive material is subjected to a high energy wave which can be either a sound wave or an electromagnetic wave which will initiate a chemical reaction in the explosive material which chemical reaction will produce heat. The heat is then sensed by a thermal imaging device which will provide a signal to a computing device which will alert a user of the apparatus to the possibility of an explosive device being present.

International Nuclear Information System (INIS)

The original purpose of this research was an investigation into the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three main objectives namely, the development of a suitable ion injector, the growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components parts into a suitable proof of principle demonstration of the wave accelerator. This work focusses on the first two of these objectives.

Energy Technology Data Exchange (ETDEWEB)

Part I of this thesis is on long-term iceberg collision-risk assessment methods for fixed offshore structures. Estimates for the long-term probability that an iceberg will hit a fixed offshore structure are based on estimates of the total volume of produced iceberg, a model for the size distribution of icebergs and a description of how iceberg trajectories ``fill`` the plane (the ocean`s surface). Part II of the thesis discusses methods for analysis of low resolution data in the sense that the size of the area covered by each pixel is not small compared to the dominating floes. Still, this type of data can provide estimates of the ice extent (and hence the ice edge) and ice concentration. The estimates of the ice edge (at least) seem to be physically significant in the sense that ``in some way`` they can reflect ice drift in an image time sequence. A priori this is far from obvious. A central idea is that the ``ice edge`` is close to a transition zone between two ...

Wastenet

... The National Oceanography Centre, Southampton is one of the world's leading research centres for the study of ocean and earth sciences. Southampton General Hospital One of the country's leading teaching hospitals and the base for the University's School of Medicine. Winchester School of Art Founded in 1863, Winchester School of Art is based 12 miles (20 kilometres) north of Southampton in the historic city of Winchester,...

Energy Technology Data Exchange (ETDEWEB)

This report highlights the significance of the geological sciences to the nation and to society. Discussions include understanding plate tectonics and surface processes, exploring the continental crust, ocean basins and the deep earth, applications of geology to social problems such as mineral resources, waste disposal, siting of critical facilities, geological hazards, water resources management, and coastal zones. The state of health of geological research is also discussed. (ACR)

Wastenet

... 01, 2009 | Rate It Marine Technology Society https://www.mtsociety.org/home.aspx emphasizes the importance of marine technology as it applies to global issues, encourages marine technology education and facilitates the use of marine technology in managing marine resources Added: Mar. 11, 2010 |...

UK PubMed Central (United Kingdom)

The oceanic bathypelagic realm (1000–4000 m) is a nutrient-poor habitat. Most fishes living there have pelagic larvae using the rich waters of the upper 200 m. Morphological...Full Text Available

Environmental Research Database

DescriptionRemote sensing of the sea surface from satellites in near-polar orbits has contributed greatly to our understanding of the links between physical and biological processes in marine systems. However most of this progress has been made in open oceanic waters or major upwelling areas, and many unresolved problems are encountered in coastal regions and shelf seas. In these optically complex waters, quantitative remote sensing requires a more sophisticated interpretation strategy than that implemente [continued...

Energy Technology Data Exchange (ETDEWEB)

Ammonia is a common and highly toxic pollutant which, in sufficient quantities, will adversely affect aquatic organisms. This ammonia criteria document for salt water will allow establishment of regulatory standards for ammonia discharge into estuaries, near coastal zones and oceans. Possible adverse impacts in highly sensitive and abundant ecosystems such as estuaries make regulation particularly important.

International Nuclear Information System (INIS)

Exact expressions for wave electromagnetic fields during instantaneous braking of two differently charged discs uniformly moving in the opposite directions have been derived. Analysis of their properties has been made. It is shown that electromagnetic wave fields during instantaneous braking of charges have a tearing nature and the Umov-Poynting theorem in the integral form is realized only at a certain value of parameter #alpha# which determines charges rates at the moment of braking. The value of parameter #alpha# is in the ranges from 0.5 to #sq root#3/2. The wave field is formed already in the absence of motion of charged discs. It is a good example confirming the conclusion that in the case of nonstationary electromagnetic fields, performance of reaction force of the wave field can differ fram radiation energy.

International Nuclear Information System (INIS)

Among the investigations conducted on the space shuttle flight STS 3 March 1982 was an experiment in which a 1-keV, 100-mA electron gun was pulsed at 3.25 and 4.87 kHz. The resultant waves were measured with a broadband plasma wave receiver. At the time of flight the experimental setup was unique in that the electron beam was square wave modulated and that the shuttle offered relatively long times for in situ measurements of the ionospheric plasma response to the VLF pulsing sequences. In addition to electromagnetic response at the pulsing frequencies the waves exhibited various spectral harmonics as well as the unexpected occurrence of satellite lines around those harmonics. Both phenomena occurred with a variety of different characteristics for different pulsing sequences.

CERN Document Server

Using the complex Kohn method, we have calculated variational values of phase shifts and the annihilation parameter, Z_{eff}, for the elastic scattering of positrons by molecular hydrogen. Our results are sensitive to small changes in the accuracy of the wave function representing the target hydrogen molecule. We have developed a systematic approach to demonstrate that, at low positron energies, there are particular forms of the Kohn trial wave function for which the results of variational calculations are not reliable, even when the target wave function accounts for as much as 96.8% of the correlation energy of H_{2}. We find that reliable results can be recovered if our calculations are extended to admit more sophisticated target wave functions accounting for 99.7% of the correlation energy. Remaining discrepancies between theory and experiment are briefly discussed.

Energy Technology Data Exchange (ETDEWEB)

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. Here we calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favourable for wave amplification from alpha energy. We find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large ...

Energy Technology Data Exchange (ETDEWEB)

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy ...

British Library Electronic Table of Contents (United Kingdom)

The purpose of this paper is to establish probabilistic models for still-water loads, based on design data, and the combined still-water and wave load effects for semi-probabilistic and probabilistic design of floating production, storage and offloading vessels (FPSO). A new still-water load model for FPSOs is proposed, based on a Poisson square-wave model, with a modified Weibull distribution for load intensity, which accounts for load control during operation. The long-term variation of wave-induced load effects is modelled by a Poisson square-wave process. A new solution for the combined effect is derived. A procedure for determining characteristic extreme values for individual and combined load effects, and load combination factors, is established. The methodology is used to illustrate...

British Library Electronic Table of Contents (United Kingdom)

BackgroundWave reflection during the systole increases left ventricular (LV) pressure, tension-time index (TTI) and myocardial oxygen requirement. The purpose of this study was to extract that component of extra myocardial oxygen requirement that is due to early systolic wave reflection, define it as wasted effort (?Ew), and examine its relationship to LV hypertrophy (LVH).MethodsRadial artery pressure waveforms were recorded using applanation tonometry and central aortic waveforms generated in 98 patients with untreated hypertension. Aortic augmentation index (AIa), wave reflection amplitude (i.e., aortic augmented pressure (AG)) and systolic duration (ED?Tr), ejection duration (ED) and round-trip travel time of the pressure wave (Tr) were calculated from the aortic waveform, a...

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 ...

Energy Technology Data Exchange (ETDEWEB)

A shock wave appears when the release of accumulated energy is instantaneous. For instance, it accompanies gunpowder explosion, electric discharge, laser beam convergence, collision of high-speed objects, release of high-pressure gas, and supersonic flight. The shock wave research center of Institute of Fluid Science, Tohoku University, is engaged in researches to elucidate the basics of various shock wave phenomena and to apply the fruit to engineering, science, and medicine. In this report, some examples of recent application studies at the center are described, and the trend of shock wave researches in the future is introduced. The ultimate state of the stagnation point of a nozzle flow simulating a reentry into the atmosphere is produced by shock wave compression in a free piston shock tube which is a ground-borne experimental apparatus. Los Alamos National Laboratory, U.S., ...

Energy Technology Data Exchange (ETDEWEB)

In this experiment, a beam incident from an oblique direction is reflected by a spherical lens toward the direction of incidence. When the surface of a matter is vibrated by elastic waves, the spherical lens comes into a translation motion that accompanies the vibration. It follows accordingly that the vibration on the surface of the matter may be detected by sensing the spherical lens travelling speed. Three components of the vibration may be determined if beams are focused at one spot from three directions. Detection of the S-wave component by LDV (laser Doppler vibrometer) discloses the complicated wave field in a heterogeneous material, and this physical model experiment may be utilized in various fields of study. For instance, information about problems that may surface in the field work may be collected beforehand in a physical model experiment for developing an S-wave-aided probing method. For ...

Energy Technology Data Exchange (ETDEWEB)

Smoothness-constrained least-squares technique with ABIC minimization was applied to the inversion of phase velocity of surface waves during geophysical exploration, to confirm its usefulness. Since this study aimed mainly at the applicability of the technique, Love wave was used which is easier to treat theoretically than Rayleigh wave. Stable successive approximation solutions could be obtained by the repeated improvement of velocity model of S-wave, and an objective model with high reliability could be determined. While, for the inversion with simple minimization of the residuals squares sum, stable solutions could be obtained by the repeated improvement, but the judgment of convergence was very hard due to the smoothness-constraint, which might make the obtained model in a state of over-fitting. In this study, Love wave was used to examine the applicability of the ...

International Nuclear Information System (INIS)

In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require ...

Energy Technology Data Exchange (ETDEWEB)

This thesis develops methods for recording and analysis of seismo-acoustic interface waves for determination of shear wave velocity as a function of depth and includes this in standard refraction seismic surveying. It investigates different techniques for estimation of dispersion characteristics of the interface waves and demonstrates that multi sensor spectral estimation techniques improve the dispersion estimates. The dispersion estimate of the fundamental interface wave mode is used as input to an object function for a model based linearized inversion. The inversion scheme provides an estimate of the shear wave velocity as a function of depth. Three field surveys were performed. Data were acquired with a standard bottom deployed refraction seismic hydrophone array containing 24 or 48 receivers, with a receiver spacing of 2.5 m. Explosive charges were used as sources. The ...

CERN Document Server

Gravitational parity violation is a possibility motivated by particle physics, string theory and loop quantum gravity. One effect of it is amplitude birefringence of gravitational waves, whereby left and right circularly-polarized waves propagate at the same speed but with different amplitude evolution. Here we propose a test of this effect through coincident observations of gravitational waves and short gamma-ray bursts from binary mergers involving neutron stars. Such gravitational waves are highly left or right circularly-polarized due to the geometry of the merger. Using localization information from the gamma-ray burst, ground-based gravitational wave detectors can measure the distance to the source with reasonable accuracy. An electromagnetic determination of the redshift from an afterglow or host galaxy yields an independent measure of this distance. Gravitational parity ...

International Nuclear Information System (INIS)

We have calculated the on-axis spectrum of spontaneous radiation emitted by an electron moving along a planar undulator that has a magnetic profile along the axis that approximates a square wave. (This could be obtained in practice by driving a ferromagnetic undulator into saturation by excessivecurrent in the windings.) We find considerable enhancement of the harmonic radiation spectrum. We compare the harmonic power emitted by an electron moving through an undulator having a sine-wave field profile with the radiation emitted from an undulator having a square-wave profile; the latter is approximated by the first three Fourier components of the undulator magnetic field profile along the axial direction. Examples are computed for 40MeV electrons taking K1 is greatly enhanced for the approximate square-wave magnetic profile: the ratio of the power emitted at f=5 by the square-wave ...

International Nuclear Information System (INIS)

The study of the scrape-off layer (SOL) during Alfven wave heating may lead to a better understanding of the antenna-plasma interaction. The scrape-off layer of the TCA tokamak has been widely investigated by means of Langmuir probes. The aim of this work is to present measurements on the influence of the Alfven wave spectrum on the scrape-off layer. These experiments have shown that the plasma boundary layer is strongly affected by the wave field, in particular the ion saturation current and the floating potential. In TCA, as the spectrum evolves due to a density rise, the passage of the Alfven continua and their associated eigenmodes, the Discrete Alfven Wave (DAW) induces a strong depletion in the edge density of up to 70% during the continuum part and a density increase during the crossing of an eigenmode. The floating potential becomes negative during the continua and even more negative crossing ...

Energy Technology Data Exchange (ETDEWEB)

California's pacific coast stretches roughly over 11.5 latitudinal degrees, extending from about 32.5{sup o}N to 44{sup o}N. There is nearly 900nm of California coastline offering superior opportunity for wave energy use. The longitudinal position of the coast shifts eastward at two distinct locations: Punta Gorda just south of Cape Mendecino in the north and Point Conception in the south. The change in longitudinal orientation in southern California also coincides with significant change in California's bathymetry. The tilts in the longitudinal coastal lines at the two points also define California wave zones into three areas: the short coastal line north of Punta Gorda, the long north and middle line between the two points, and the short line of the heavily populated southern coast. The northern and central zones are characterized by high waves of relatively low frequency; the southern coast is ...

British Library Electronic Table of Contents (United Kingdom)

The discussion focuses on the ways in which the 3 panelists in their lives and work embody fourth wave feminism, which combines politics, psychology, and spirituality in an overarching vision of change. Jane Fonda's emphasis on the importance of making narratives of gender a central organizer for personal and societal transformation, Hedda Bolgar's insistence that psychoanalysts recognize the complex dialectic between unconscious dynamics and sociocultural realities in order not to conflate conflicts rooted in social inequalities with individual issues, and Sue Shapiro's understanding of the ambiguous role of individual therapy in situations of historical and social trauma such as the tsunami in Indonesia are all examples of fourth wave feminism in practice. The unfinished business of the ...

Science.gov (United States)

A previous paper introduced the use of wave digital filters as a basic building block for power system simulation, particularly suitable for real-time applications. This paper stresses the simulation of non-linear and switching elements, emphasizing the advantages of the wave filters implementation. The digital structure is maintained even when non-linear components change their characteristics or power electronic devices switch their states. As a very important by-product, the suppression of numerical oscillations related to the trapezoidal rule is achieved in a rather simple way, with no effects on simulation results.

Science.gov (United States)

This paper discusses the influence of an endoscope on the peristaltic flow of a couple stress fluid in an annulus under a zero Reynolds number and long wavelength approximation. The inner tube is uniform, rigid, while the outer tube has a sinusoidal wave traveling down its wall. Analytical expressions for the axial velocity, stream function and axial pressure gradient are established. The flow is investigated in a wave frame of reference moving with the velocity of the wave. Numerical calculations are carried out for the pressure rise, frictional forces and trapping. The features of the flow characteristics are analyzed by plotting graphs and discussed in detail.

CERN Document Server

The influence of motion of ions and electron temperature on nonlinear one-dimensional plasma waves with velocity close to the speed of light in vacuum investigated. It is shown that although the wavebreaking field weakly depends on mass of ions, the nonlinear relativistic wavelength essentially changes. The nonlinearity leads to the increase of the strong plasma wavelength, while the motion of ions leads to the decrease of the wavelength. Both hydrodynamic approach and kinetic one, based on Vlasov-Poisson equations, are used to investigate the relativistic strong plasma waves in a warm plasma. The existence of relativistic solitons in a thermal plasma is predicted.

International Nuclear Information System (INIS)

This article considers the application of simple trial wave functions to calculate the ground state energy of a hydrogen-like center near the interface of two media. Calculations have been performed taking into account the image potential. It has been shown that different kinds of wave functions are optimal at different distances from the interface. A relatively simple wave function has been suggested to represent main features of the dependence of the ground state energy on the distance to the interface. (authors)

Energy Technology Data Exchange (ETDEWEB)

The adsorption capacity of radionuclides onto suspended sediment was experimented on each of the coastal seawater sampled around the Kori and the Wolsung nuclear power plant. During the experiment the quantity and size fraction of suspended sediment were adjusted and the seawater and sediment chemistry is approximated to the expected field condition. Because the sorption capacity depends on the specific minerals, ocean chemistry and radionuclide involved, it is necessary to analyze sediment mineralogy. Clay mineral is dominant in seabed mineral and suspended sediment as the result of x-ray diffraction. Radionuclide sorbed to silty-clay mineral can be rather transported to ocean than scavenged to seabed because of low quantity and fine grained suspended sediment in the coast around the Kori and the Wolsung. The result of adsorption examinations shows that {sup 139}Ce and {sup 51}Cr and {sup 110m}Ag are strongly sorbed to suspended particle, ...

Energy Technology Data Exchange (ETDEWEB)

The authors have discovered chert xenoliths from green rocks in the Pippu area, central Hokkaido, Japan. Reports were given on the discovery with regard to the state of its production, chemical composition of the green rocks, and radiolarian fossils produced from the chert and their age. Considerations were given on the geological significance thereof. On 23 green rocks and five cherts out of the collected samples, rock slices were prepared, and petrographic statement was made by using a polarizing microscope. In addition, the whole petro-chemical composition analysis was performed on green rocks to discuss the radiolarian fossils and geological ages. The following conclusions were obtained as a result: green rocks may be identified as a product of igneous activities in a large plate in a certain period from the latter Callovian period of the middle age of the Jurassic period to the Barremian period of the Paleozoic era in the Cretaceous period; and their formation field should have ...

Science.gov (United States)

Are there wave-cut shore lines? Ripple marks? Scablands? Gravel and sand bars? .... these pictures will nally tie together the view from Mars' sur- ...

International Nuclear Information System (INIS)

The problem of fast wave plasma heating in reactor-torsatron at the ICRF range in scenarios, optimal for fusion reactor, is numerically studied.

International Nuclear Information System (INIS)

(13 May 1974). Netherlands Bimbot, L. Brissaud, I. Le Bornec, Y. Tatischeff,

International Nuclear Information System (INIS)

... 900526-11-8 277 p. MATERIALS SCIENCE antiferromagnetic materials cerium

Science.gov (United States)

... Zou, S. and RA Dalrymple, ``Coastal Sediment Transport Simulation by Smoothed Particle Hydrodynamics,'' Journal of Waterways, Ports, Coastal ...

Energy Technology Data Exchange (ETDEWEB)

The authors examine the overheating of a chemical detonation wave, which results in hybrid detonation processes, for example, photochemical or electrochemical detonation, depending on the source. The schemes for obtaining the overheated detonation are shown. Analysis has shown that: normal stationary overheated detonation waves are possible when the overheating power density is constant, just as when the specific energy of overheating is constant; the use of the ''gas'' equation of state for describing overheated detonation in condensed explosives yields wave parameters which are too high; and the assumption that the chemical energy released in the explosive is independent of the overheating energy also leads to wave parameters which are too high, and the overestimation increases as the overheating is intensified.

Science.gov (United States)

... A. Fasano, SD Howison. JR Ockendon & M. Primicerio. Some remarks on the regularisation of the supercooled one-phase Stefan problem. Quart. ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

... thus can function as switches -6 ... Akkari, "Optical Channel Waveguide Switch and Coupler ... Wide-Band Guided Wave Acousto-Optic Bragg Diffraction ...

Energy Technology Data Exchange (ETDEWEB)

Every Bianchi type-IX universe can be interpreted as a closed Friedmann universe on which is superimposed circularly polarized gravitational waves with the longest wavelength that will fit into a closed universe. In this paper, I give a new derivation of this result based on the concept of homogeneous tensor fields on the three-sphere. Every homogeneous symmetric traceless tensor field is shown to be a longest-wavelength three-sphere harmonic. Contrary to previous authors, I show that the wavelength of these gravitational waves is one-half the circumference of the universe. In order to maintain homogeneity, the gravitational waves must all have the same polarization. There are five longest-wavelength modes for each polarization. This interpretation is an {ital exact} description that is valid for every Bianchi type-IX universe---it is in no way limited to first-order perturbations of a Friedmann universe.

Energy Technology Data Exchange (ETDEWEB)

In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

International Nuclear Information System (INIS)

An estimation method of plasma density based on surface plasmons theory for surface-wave plasmas is proposed. The number of standing-wave is obtained directly from the discharge image, and the propagation constant is calculated with the trim size of the apparatus in this methods, then plasma density can be determined with the value of 9.1 x 1017 m-3. Plasma density is measured using a Langmuir probe, the value is 8.1 x 1017 m-3 which is very close to the predicted value of surface plasmons theory. Numerical simulation is used to check the number of standing-wave by the finite-difference time-domain (FDTD) method also. All results are compatible both of theoretical analysis and experimental measurement. (authors)

International Nuclear Information System (INIS)

The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic ...

Energy Technology Data Exchange (ETDEWEB)

As characterization of artificial cracks formed underground by using the water pressure fracturing method, experiments have been carried out to detect relationship of pressurization and S-wave propagation time with the polarizing direction dependence. Openings are created when pressure in the vicinity of the artificial cracks increases greater than reopening pressure of micro cracks. Elastic wave velocity decreases in this region because of water in the opened micro cracks. Anisotropy is created in the S-wave propagation velocity due to influence from anisotropic reopening region when the artificial cracks are pressurized, and is separated into two components which polarize orthogonally with each other (micro splitting). Field experiments conducted at the Higashi-hachimantai field were analyzed by using wavelet transform. It was possible to detect the S-wave arrival time at high accuracy, and the ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...

International Nuclear Information System (INIS)

(1 Aug 1972). United States Belakhovskii, M. Pierre, J. Ray, DK v.

Energy Technology Data Exchange (ETDEWEB)

Gas hydrates have impacted the oil and gas industry since 1934, when they were first found to plug pipelines. Today we know that in deep oceans and in permafrost, very substantial gas reserves are present in hydrated form. Concerns are being raised about in situ dissociation for both energy and greenhouse implications upon methane release. In Japan work is underway to consider the storage of carbon dioxide, concentrated in clathrates. This talk will deal with some basic questions. Why should we be interested in gas hydrates? What are gas hydrates? How do gas hydrates form? How might hydrates impact on the energy/environmental picture?

Energy Technology Data Exchange (ETDEWEB)

A shock absorber mechanism and method for use on the leg structure of a jack-up offshore drilling rig is described. It is mounted on the bottom of each existing leg of a drilling rig and comprises a pointed piston member which is positioned on the bottom of the leg structure and projects downwards through the can/footing of the rig leg. The piston member is held in place by a resilient tension member which is designed to absorb shock forces during vertical/axial impact of the leg structure when contact is made with the ocean floor. (author).

Energy Technology Data Exchange (ETDEWEB)

In the United States, economic growth increasingly requires that greater volumes of freshwater be made available for new users, yet supplies of freshwater are already allocated to existing users. Currently, water for new users is made available through re-allocation of xisting water supplies-for example, by cities purchasing agricultural water rights. Water may also be made available through conservation efforts and, in some locales, through the development of ''new'' water from non-traditional sources such as the oceans, deep aquifer rackish groundwater, and water reuse.

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... (restricted)] 319-341 The value of container terminal investment to ocean carrier strategy by Thomas Pawlik & Lars Stemmler & Alfred J Baird ... (restricted)] 142-173 Prediction of arrival times and human resources allocation for container terminal by Gianfranco Fancello & Claudia Pani & Marco Pisano ... (restricted)] 347-369 Analysis of berth allocation and inspection operations in a container terminal by Yongpei Guan & Kang-hung Yang [Downloadable! (... (restricted)] 237-262 Container terminal concessions: A game theory application to the case of the ports of Pakistan by Naima Saeed & Odd ...

Energy Technology Data Exchange (ETDEWEB)

A study for Cs-137 radionuclide dispersion in the marine environment through of compartmental model (Box Model) is presented. The model simulates the surface water contamination caused by direct atmospheric deposition, surface wash off, desorption from sediments and transfer with the ground water of accidentally released radionuclides. For this study the model was applied to the North Sea, near to Sellafield, based on the transfer coefficients obtain at the literature. The results obtained are in good agreement with the literature, being that the model developed can be applied in to the brazilian coastal regions. (author). 7 refs, 7 figs.

Energy Technology Data Exchange (ETDEWEB)

In this project we determined primary production and optical variability in the shelf and slope waters off of Cape Hatteras, N.C. These processes were addressed in conjunction with other Ocean Margins Program investigators, during the Spring Transition period and during Summer. We found that there were significant differences in measured parameters between Spring and Summer, enabling us to develop seasonally specific carbon production and ecosystem models as well as seasonal and regional algorithm improvements for use in remote sensing applications.

Energy Technology Data Exchange (ETDEWEB)

A review of theoretical and observational research on the magnetopause during 1987-1990. Starting with recent work on magnetic reconnection, the review proceeds to magnetopause surface wave phenomena, including the controversy over the role of solar wind pressure pulses in the coupling process and in the mimicking of flux transfer events signatures, and finishes with the magnetopause structure and associated wave phenomena. Recent advances in computer modeling of the magnetopause and the pertinent processes are also discussed. 108 refs.

International Nuclear Information System (INIS)

The electron-phonon coupling constant lambda has been calculated for vanadium. The electron energy bands and wave functions were obtained from a model augmented plane wave muffin-tin potential. The electron-phonon matrix elements were evaluated using the rigid-ion approximation and the measured phonon spectra. The results show that lambda is strongly affected by d-f scattering.

International Nuclear Information System (INIS)

The wavefunction of a positron in ReO is calculated using the augmented-plane-wave method. Due to the loosely-packed structure of ReO_3, the ground-state GAMMA_1 wavefunction exhibits a marked anisotropy particularly around the oxygen ions, and a large fraction of a positron is distributed in the interstitial region. Experimental results of the positron annihilation 2#gamma#-correlations and the positron annihilation rates in ReO_3 are discussed based on the positron wavefunction. (orig.).

CERN Document Server

A general theorem on the GBDT version of the B\\"acklund-Darboux transformation for systems rationally depending on the spectral parameter is treated and its applications to nonlinear equations are given. Explicit solutions of direct and inverse problems for Dirac-type systems, including systems with singularities, and for the system auxiliary to the $N$-wave equation are reviewed. New results on explicit construction of the wave functions for radial Dirac equation are obtained.

International Nuclear Information System (INIS)

Based on the nonlinear dispersion relation of electromagnetic wave in relativistic plasma, the nonlinear controlling equation for linearly polarized mode is obtained using Karpman's method. The modulation instability of intense laser pulse propagating through relativistic plasma is analyzed and the modulation instability growth rate as a function of perturbation wave number for laser beam propagating through relativistic plasma is given. (authors)

Energy Technology Data Exchange (ETDEWEB)

The t<0 branch of pre-big bang cosmological scenarios is subject to a gravitational wave instability. The unstable behaviour of tensor perturbations is derived in a very simple way in Hwang's covariant and gauge-invariant formalism developed for extended theories of gravity. A simple interpretation of this instability as the effect of an ''antifriction'' is given, and it is argued that a universe must eventually enter the expanding phase. (orig.)

CERN Document Server

In this paper we first establish global pointwise time-space estimates for a class of oscillatory integrals. Then, we use them to establish $L^p-L^q$ estimates for a class of higher order wave-type equations of the form $\\partial_{tt}u+P(D_{x})u=0$, where the symbol $P(\\xi)$ is a real non-degenerate elliptic polynomial of ${\\bf R}^n$.

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).

International Nuclear Information System (INIS)

The high-frequency precessional mode of a hot-electron-stabilized magnetic configuration has previously been shown to be stable in a window of core-plasma mass. Under conditions of frequency matching, the resulting stable negative-energy precessional wave can be destabilized by coupling to positive-energy shear-Alfven waves. Coupling is avoided when the hot-electron precession frequency exceeds the core-plasma ion gyrofrequency.

British Library Electronic Table of Contents (United Kingdom)

The method of surface acoustic waves is employed to determine the frequency and temperature dependences of the molar heat capacity of poly(vinyl chloride) on the contribution of Rayleigh local components of the longitudinal and transverse vibrations of structural units of the polymer. The calculated and experimental data are compared in terms of their dependence on the relaxation state of the system.

International Nuclear Information System (INIS)

Calculations of the Compton profiles for the transition metals Ta and W are performed, using electron wave functions obtained from self-consistent augmented plane wave (APW) band structure calculations within the local density formalism of Hedin-Lundqvist. Relativistic effects are included except for the spin-orbit interaction. The observed structures of the Compton profiles in these metals are understood in terms of the topology of their Fermi surfaces. (author).

International Nuclear Information System (INIS)

Fermi radii and velocities are determined by deconvoluting de Haas-van Alphen data. Comparison of these data with accurate augmented-plane-wave band-structure results establishes the reliability of the augmented-plane-wave calculations and allows a determination of the anisotropic many-body enhancement factor lambda(k). The Fermi-surface average of 1.33 suggests a large electron-electron contribution. Our anisotropic lambda(k) porvides a detailed test and guide for model calculations of many-body enhancement.

CERN Document Server

Acoustic waves propagation of in composite of water with embedded double-layered silicone resin/silver rods is considered. Approximate values of effective dynamical constitutive parameters are obtained. Frequency ranges of simultaneous negative constitutive parameters are found. Localized surface states on the interface between metamaterial and ``normal'' material are found. Doppler effect in metamaterial is considered. Presence of anomalous modes is shown.

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a novel control strategy for tracking peak power in a wind or wave energy system using a squirrel cage induction generator. It eliminates wind speed measurement or estimation and uses a simple scalar technique by exploiting the cubic nature of the power curve. The method works even when air velocity is varying dynamically. (author)

Energy Technology Data Exchange (ETDEWEB)

Along the Japan Sea coast in Akita Prefecture and in the vicinity, there exist active fault groups, such as the Kitayuri thrust fault group in the south and Noshiro thrust fault group in the north. It is estimated that there is another fault, running from Akita City located between the above-said two thrust fault groups into the Hachiro-kata reclaimed land, roughly connecting the two thrust fault groups. This third fault is supposed to be related to the hypocenter of Tencho Earthquake of 830, but its location and structural configuration are not known, and it is not known whether it is an active fault, either. Investigations are conducted using S- and P-waves. The greatest problem in the use of P-waves is that there exists a layer in which signal attenuation is high and transmission is anomalously slow. This problem is ascribed to the layer pore water rendered unsaturated though slightly by the inclusion of air bubbles, and is explained for the ...

Energy Technology Data Exchange (ETDEWEB)

Formulation is introduced for discretizing a boundary integral equation into an indirect boundary element method for the solution of 3-dimensional topographic problems. Yokoi and Takenaka propose an analytical solution-capable reference solution (solution for the half space elastic body with flat free surface) to problems of topographic response to seismic motion in a 2-dimensional in-plane field. That is to say, they propose a boundary integral equation capable of effectively suppressing the non-physical waves that emerge in the result of computation in the wake of the truncation of the discretized ground surface making use of the wave field in a semi-infinite elastic body with flat free surface. They apply the proposed boundary integral equation discretized into the indirect boundary element method to solve some examples, and succeed in proving its validity. In this report, the equation is expanded to deal with 3-dimensional topographic ...

CERN Document Server

The present work concerns the numeric modeling of the sea-wave instability under the effect of the logarithmic wind at hurricane conditions (ignoring non-linear effects, such as wave breaking, foam production, etc. Powell et al. (2003)^1, Shtemler et al. (2003)^2. The central point of the study is the calculation of the growth rate, which is proportional to the fractional input energy from the wind to the wave exponentially varied with time. The present modeling demonstrates that the Miles-type model applying Charnock's formula Charnock (1955)^3 for roughness to the hurricane -wind parameters underestimates the growth rate of the wind waves 5-40 times as compared with the model employing the roughness and friction velocity adopted from experimental data for hurricane winds.^1 This occurs due to Charnock's formula fails at large wind speeds. The stability characteristics obtained on the base of the ...

International Nuclear Information System (INIS)

The energy-versus-volume curve of the spin-density wave (SDW) in body-centred-cubic Cr is calculated with the density functional theory/full-potential linearized augmented plane wave (DFT/FLAPW) method using the generalized gradient approximation (GGA). The predicted ground state is not the SDW, in contrast to an earlier FLAPW calculation. A conjecture is formulated that the widely varying results of the local density approximation (LDA) and GGA - and of different solution methods - can be scaled by the size of the calculated moment. As a consequence, experimentally relevant properties of the SDW can be calculated by tuning the moment. The implications of these results for the ability of DFT to describe Cr are discussed. (author)

Energy Technology Data Exchange (ETDEWEB)

A wavelet transformation is performed over each of the spatial coordinates of the scalar wave equation. This transformed equation is solved directly with a finite-difference scheme for both homogeneous and smooth inhomogeneous media. Wavefield extrapolation is performed completely in the spatial wavelet domain without transforming back into the space domain at each time step. The wavelet coefficients are extrapolated, rather than the wavefield itself. The numerical solution of the scalar wave equation in the spatial wavelet domain is closely related to the finite-difference method because of the compact support of the wavelet bases. Poststack reverse-time migration is implemented as an application. The resolution spaces of the wavelet transform provide a natural framework for multigrid analysis. Migrated images are constructed from various resolution spaces.

Energy Technology Data Exchange (ETDEWEB)

The great advantage of the helical ionization cooling channel (HCC) is its compact structure that enables the fast cooling of muon beam 6-dimensional phase space. This compact aspect requires a high average RF gradient, with few places that do not have cavities. Also, the muon beam is diffuse and requires an RF system with large transverse and longitudinal acceptance. A traveling wave system can address these requirements. First, the number of RF power coupling ports can be significantly reduced compared with our previous pillbox concept. Secondly, by adding a nose on the cell iris, the presence of thin metal foils traversed by the muons can possibly be avoided. We show simulations of the cooling performance of a traveling wave RF system in a HCC, including cavity geometries with inter-cell RF power couplers needed for power propagation.

International Nuclear Information System (INIS)

A self-consistent pseudopotential method together with a mixed-basis set of plane waves and Gaussian orbitals are used to determine the electronic structure of the (001) surface of molybdenum. The pseudopotential is derived from a self-consistent calculation of the atomic levels and wave functions, and is tested for bulk molybdenum. The resulting bulk band structure and density of states are compared with existing augmented-plane-wave APW calculations. The same potential is applied to investigate the electronic structure of an uncontracted Mo (001) surface. A complete analysis of the surface states is given in terms of their distribution in the two-dimensional surface Brillouin zone, charge-density distribution, and the local density of states. The results are in very good agreement with recent photoemission measurements.

International Nuclear Information System (INIS)

Elastic scattering cross sections of keV protons in solids (Z=3-82) are calculated using the partial wave expansion technique and the ''muffin-tin'' bound-atom potential. The differential cross sections for small scattering angles of less than 10deg are smaller than those with the Ziegler-Biersack-Littmark potential at all energies and for all solids, although, for larger angles, the two cross sections agree with each other. The mean free paths of the protons in the solids, obtained from the total cross sections, decrease very slowly with decreasing energy. Furthermore, at low energies they approach half the nearest-neighbor distance, which is taken as the radius of the augmented plane wave sphere in the muffin-tin model of crystalline solids. (orig.).

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Wave energy device teams have identified three varieties of air turbine as potentially applicable to wave energy devices. These are: conventional axial turbines; Wells, or self-rectifying, axial turbines and Francis turbines. This report examines the constructional requirements of these devices with regard to mechanical, environmental and manufacturing considerations. It is concluded that the major benefit of optimum material selection will be reduced manufacturing costs rather than enhanced turbine performance. A methodology of material selection has been established and candidate materials have been listed for the major components of each turbine type. Comparative costs for alternative materials are included, from which significant, potential economies have been identified. Recommendations are made aimed at achieving optimum material usage in the proposed turbines.

International Nuclear Information System (INIS)

This paper reviews generation methods of artificial earthquake motion and proposes an improved method of generating input motions for use in vibration tests of equipment to prove aseismic performance. The improved method employs beat wave repetition characteristic that inherently appears in the component waves of recorded earthquakes decomposed by bandpass filter and algebraic function phase for the component waves. Typical motions generated by the improved method satisfies prescribed severe conditions such as target response spectrum that are defined with a wideband frequency component and a limited maximum acceleration due to shaking table performance. The motions had never been generated by the conventional method.

International Nuclear Information System (INIS)

First-principles density functional theory (DFT) based calculations were performed to study the electronic and cohesive properties of all the intermediate ordered phases appearing in the transformation from bcc-based #beta# to hexagonal ordered #omega# phase in Zr_3Al alloy. Full-potential linear augmented plane wave (FPLAPW) method under the GGA was employed to establish the stability hierarchy and structure-property correlations. Further, effective pair potentials upto the fourth nearest neighbours were extracted, which, subsequently, were used for the thermodynamics analysis of the thermally-induced #beta##->##omega# transformation. The lattice collapse mechanism involving the concept of the onset of a displacement wave where the extent of collapse is viewed as an amplification of the displacement wave was employed for further analysis. (author)

International Nuclear Information System (INIS)

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.

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.

CERN Document Server

A fundamental Doppler-like but asymmetric wave effect that shifts received signals in frequency in proportion to their respective source distances, was recently described as means for a whole new generation of communication technology using angle and distance, potentially replacing TDM, FDM or CDMA, for multiplexing. It is equivalent to wave packet compression by scaling of time at the receiver, converting path-dependent phase into distance-dependent shifts, and can multiply the capacity of physical channels. The effect was hitherto unsuspected in physics, appears to be responsible for both the cosmological acceleration and the Pioneer 10/11 anomaly, and is exhibited in audio data. This paper discusses how it may be exploited for instant, passive ranging of signal sources, for verification, rescue and navigation; incoherent aperture synthesis for smaller, yet more accurate radars; universal immunity to jamming or interference; and precision ...

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The specific goals of this research are to (1) determine daily and seasonal variability of seawater pCO{sub 2} partial pressure of CO{sub 2} and NO{sub 3} in Middle Atlantic Bight (MAB) waters; (2) estimate seasonal CO{sub 2} fluxes between the MAB shelf and the atmosphere; and (3) determine the primary controls of surface seawater pCO{sub 2} in this coastal system. During the first phase of the DOE-OMP (1992-1995) we developed the Submersible Autonomous Moored Instrument for CO{sub 2} (SAMI-CO{sub 2}) which is designed to measure seawater CO{sub 2} on ocean moorings for extended periods.

Energy Technology Data Exchange (ETDEWEB)

In the study, wind data from the Comprehensive Ocean-Atmosphere Data Set (COADS) are used to determine atmospheric circulation changes which are empirically associated with the air temperature changes. Some understanding of the natural processes which produce climate change is anticipated from the study of these associations. Systematic changes of wind in US coastal regions with periods of climate warming and cooling suggest circulation changes, in addition to carbon dioxide-controlled radiation effects, could produce the climate changes indicated by air temperature. A statistical procedure for analyses of COADS was used to determine decade-period vector wind-field differences from the COADS record period. The statistical procedure for these analyses is explained and the wind differences are compared to summaries of mid-Atlantic coast island-station observations.

CERN Document Server

This is our response to a comment by Walter Eifler on our paper `A simple model for the short-time evolution of near-surface current and temperature profiles' (arXiv:physics/0503186, accepted for publication in Deep-Sea Research II). Although Eifler raises genuine issues regarding our model's validity and applicability, we are nevertheless of the opinion that it is of value for the short-term evolution of the upper-ocean profiles of current and temperature. The fact that the effective eddy viscosity tends to infinity for infinite time under a steady wind stress may not be surprising. It can be interpreted as a vertical shift of the eddy viscosity profile and an increase in the size of the dominant turbulent eddies under the assumed conditions of small stratification and infinite water depth.