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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.

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...

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/...

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...

Science.gov (United States)

Decadal-scale climate variations over the Pacific Ocean and its surroundings are strongly related to the so-called Pacific decadal oscillation (PDO) which is coherent with wintertime climate over North America and Asian monsoon, and have important impacts on marine ecosystems and fisheries. In a near-term climate prediction covering the period up to 2030, we require knowledge of the future state of internal variations in the climate system such as the PDO as well as the global warming signal. We perform sets of ensemble hindcast and forecast experiments using a coupled atmosphere-ocean climate model to examine the predictability of internal variations on decadal timescales, in addition to the response to external forcing due to changes in concentrations of greenhouse gases and aerosols, volcanic activity, and solar cycle variations. Our results highlight that an initialization of the upper-ocean state using historical ...

Energy Technology Data Exchange (ETDEWEB)

''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.

Environmental Research Database

ObjectivesNot EnteredDescriptionMethane hydrate in an ice-like substance consisting of molecules of methane gas combined chemically with water. It is stable at high pressures and low temperatures. Since the ocean floor is normally cold, but temperatures increase with depth inside the Earth, such conditions normally prevail for a few hundred meters below the seafloor where the ocean depth is more than a few hundred metres. Methane beneath the ocean floor is formed by the decomposition of organic material. At the edges of the co [continued...

International Nuclear Information System (INIS)

In the utilization of the thermal energy by ocean temperature difference and factory waste heat, the high performance heating surfaces in pipes from which scale can be removed are required. As the method of removing scale, the method using sponge balls seems most suitable, but for applying this method, as the form of the protrusions attached to the inner surfaces of pipes, smooth circular are form is desirable. The promotion of heat transfer with the rows of circular arc protrusions like this is strongly related to the mode of flow and such structure as separation, recirculation flow, readhesion and turbulent energy generation. In this study, as the basic research to optimize the heating surface with the rows of smooth protrusions, the flow characteristics and the heat transfer characteristics including the turbulent structure of the wake of protrusions were experimentally ...

International Nuclear Information System (INIS)

Present and potential future changes to the global environment have important implications for marine pollution and for the air-sea exchange of both anthropogenic and natural substances. This report addresses three issues related to the potential impact of global change on the air-sea exchange of chemicals: Global change and the air-sea transfer of the nutrients nitrogen and iron. Global change and the air-sea exchange of gases. Oceanic responses to radiative and oxidative changes in the atmosphere. The deposition of atmospheric anthropogenic nitrogen has probably increased biological productivity in coastal regions along many continental margins. Atmospheric deposition of new nitrogen may also have increased productivity somewhat in mid-ocean regions. The projected future increases of nitrogen oxide emissions from Asia, Africa and South America will provide significant increases in the rate of deposition of oxidized nitrogen to the central ...

Science.gov (United States)

The ratio of particle velocity to translation speed exceeds 1 for 98% of .... The westward movement of the meandering jet and eddy system transports nutrient- rich ...... J. Hydrometeor., 4, 1044-1066. Gedney, N., P. M. Cox, H. Douville, ...

Energy Technology Data Exchange (ETDEWEB)

The oceanic phytoplancton productivity may essentially influence the total rate of the atmospheric CO{sub 2} absorption by the ocean - that is, a considerable amount of CO{sub 2} will be taken-up in the 50 micrometers thick layer near the air-sea interface. Even if phytoplancton production constitutes only 5% of the total oceanic biota production, this will increase the rate of CO{sub 2} absorption more than twice compared with the present estimates. The reason is that metabolic activity of phytoplancton leads to the emergence in a thin scin (50 micrometers, the average size of phytoplancton cells) layer near the water surface of an additional minimum in the CO{sub 2} partial pressure profile and of an additional maximum of {Delta} {sup 13}C in the same area. These two extremums cannot be detected if the corresponding characteristics are averaged over any microscopic area in the well mixing layer that ...

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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 ...

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)

Measurements of dissolved and atmospheric nitrous oxide (N{sub 2}O) are presented for three coastal environments: (1) the central North Sea, (2) the German Bight, and (3) the Gironde estuary. The contribution of coastal regions to the oceanic emissions of atmospheric N{sub 2}O were also determined. N{sub 2}O was measured with a gas chromatograph equipped with an electron capture detector and analyzed. The surface waters of the central North Sea and the German bight were found to be near equilibrium with the overlying atmosphere, while the mean saturation in the Gironde estuary was 132%. Mean saturations in coastal regions without estuaries or upwelling phenomena were only slightly higher than in the open ocean. When estuaries and regions with upwelling are included, however, approximately 60% of the oceanic N{sub 2}O flux is attributable to coastal regions. A review of published data indicated that ...

International Nuclear Information System (INIS)

Exposure of cells to light of less than 320 nanometers wavelengths may lead to lethal lesions and perhaps carcinogenesis. Many organisms have evolved mechanisms to repair U.V. light-induced damage. Organisms such as deep-sea bacteria are presumably never exposed to U.V. light and perhaps occasionally to visible from bioluminescence. Thus, the repair of U.V. damage in deep-sea bacterial DNA might be inefficient and repair by photoreactivation unlikely. The bacteria utilized in this investigation are temperature sensitive and barophilic. Four deep-sea isolates were chosen for this study: PE-36 from 3584 m, CNPT-3 from 5782 m, HS-34 from 5682 m, and MT-41 from 10,476 m, all are from the North Pacific ocean. The deep-sea extends from 1100 m to depths greater than 7000 m. It is a region of relatively uniform conditions. The temperature ranges from 5 to -1"0C. There is no solar light in the deep-sea. Deep-sea bacteria are ...

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.

Science.gov (United States)

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Science.gov (United States)

An observational and modeling study was performed over the Arabian Gulf region to investigate the coastal circulations and aerosol transport in the area. Climatological data and observations from the United Arab Emirates' Unified Aerosol Experiment were used to develop a better understanding of the complex meteorological processes in the Arabian Gulf region. Climatological data suggests that sea breezes occur on more than 77 percent of days in all months of the year and land breezes occur on more than 70 percent of the days. The occurrence of the sea and land breeze circulations are higher (90-99 percent) during the summer months when large-scale weather patterns are quiescent. Measurements of aerosol concentrations taken during the Unified Aerosol Experiment(2004) experiment are used to investigate aerosols, namely dust, transported in the Arabian Gulf region. Vertical profiles of dust concentration along with vertical profiles of potential temperature and wind ...

Energy Technology Data Exchange (ETDEWEB)

The metabolism of organic matter in the coastal regions of the ocean may significantly affect the oceanic carbon budget. This paper describes the high percentage (30%) of oceanic oxidation that occurs in coastal areas and the impact of this metabolism on the carbon cycle and climate of earth. Organic metabolism in the ocean appears to be a source of carbon dioxide release into the atmosphere. Oxidation in the coastal zone is of special interest, as it is likely influenced by anthropogenic activity. Recommendations for future research on this topic are proposed. 129 refs., 2 figs., 6 tabs.

Energy Technology Data Exchange (ETDEWEB)

This paper presents results, numeric and experimental, due to installation operation of a Risers Uphold Sub-Surface Buoy, (BSR). This kind of installation developed by PETROBRAS is unique in the world. The work of BSR installation was based on a numeric pre analysis to verify the system and determine the main parameters to be experimentally verified. The second phase of the work was the experimental analysis in a deep water ocean basin. s. The work describes the BSR and their main accessories, the experimental environment and the model constructed in aluminum in a 1:12 scale and the main results. (author)

Energy Technology Data Exchange (ETDEWEB)

Climates at regional scale are strongly dependent on the interaction between atmosphere and its lower boundary, the oceans and the land surface mosaic. Land surfaces influence climate through their albedo, and the aerodynamic roughness, the processes of the biosphere and many soil hydrological properties; all these factors vary considerably geographically. Land surfaces receive a certain portion of the solar irradiance depending on the cloudiness, atmospheric transparency and surface albedo. Short-wave solar irradiance is the source of the heat energy exchange at the earth`s surface and also regulates many biological processes, e.g. photosynthesis. Methods for estimating solar irradiance, atmospheric transparency and surface albedo were reviewed during the course of this project. The solar energy at earth`s surface is ...

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.

Science.gov (United States)

In 2009 the European Space Agency satellite mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was launched. Its objectives are the precise and detailed determination of the Earth's gravity field and geoid. Its core instrument, a three axis gravitational gradiometer, measures the gravity gradient components V xx , V yy , V zz and V xz (second-order derivatives of the gravity potential V) with high precision and V xy , V yz with low precision, all in the instrument reference frame. The long wavelength gravity field is recovered from the orbit, measured by GPS (Global Positioning System). Characteristic elements of the mission are precise star tracking, a Sun-synchronous and very low (260 km) orbit, angular control by magnetic torquing and an extremely stiff and thermally stable instrument environment. GOCE is complementary to GRACE (Gravity Recovery and Climate Experiment), another satellite gravity mission, launched in 2002. While ...

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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)

Energy Technology Data Exchange (ETDEWEB)

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)

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

British Library Electronic Table of Contents (United Kingdom)

A mission to the surface of Venus would have high scientific value, but most electronic devices and sensors cannot operate at the 450degreeC ambient surface temperature of Venus. Power and cooling systems were analyzed for Venus surface operation. A radioisotope power and cooling system was designed to provide electrical power for a probe operating on the surface of Venus. For a mission duration of substantial length, the use of thermal mass to maintain an operable temperature range is likely impractical, and active refrigeration may be required to keep components at a temperature below ambient. Due to the high thermal convection of the high-density atmosphere, the heat rejection temperature was assumed to be at a 500degreeC radiator temperature, 50degreeC above ambient. The radioisotope S...

Science.gov (United States)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the ...

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This paper describes a 1993 field experiment entitled Marine Aerosol Properties and Thermal Imager Performance Trial (MAPTIP) conducted by NATO AC/243 Panel 04/RSG.8 and 04/RSG.5 in the Dutch coastal waters. Objectives were: to improve and validate vertical marine aerosol models by providing an extensive set of aerosol and meteorological measurements, within a coastal environment at different altitudes and for a range of meteorological conditions; make aerosol and meteorological observations in the first 10 m of the ocean surface with a view to extending existing aerosol models to incorporate near-surface effects; and to assess marine boundary layer effects on thermal Imaging systems. Aerosol and meteorological instruments, as well as thermal imagers and calibrated targets, were utilized. This network of instrumentation has provided a comprehensive database of aerosol size distribution profiles and relevant meteorological ...

International Nuclear Information System (INIS)

Experiments of plasma nitriding of titanium are carried out by two plasma sources. One is a microwave discharge plasma source under several Torr, and the other is a nitrogen arc jet generated under atmospheric pressure followed by rapid expansion into a gas wind tunnel. The relationship between the surface density of nitrogen atoms in the #alpha#-Ti and various plasma parameters is systematically studied. For the microwave nitrogen plasma, it is found that the effect of the vibration temperature is the most essential for the surface nitriding, whereas the effect of electron temperature, density and rotation temperature is less remarkable. It is also found that the higher vibration temperature of the microwave discharge nitrogen plasma makes the target temperature higher, and consequently, the surface density of atomic ...

International Nuclear Information System (INIS)

The 2-step low temperature plasma processes (the combined carburizing and post-nitriding) were carried out for improving both the surface hardness and corrosion resistance of AISI 316L stainless steel. The effects of processing time and temperature on the surface properties during nitriding step were investigated. The expanded austenite (#gamma#N)was formed on all of the treated surface. The thickness of #gamma#N was increased up to about 20 #mu#m and the thickness of entire hardened layer was determined to be about 40 #mu#m. The surface hardness reached up to 1,200 HV_0_._1 which is about 5 times higher than that of untreated sample (250 HV_0_._1). The thickness of #gamma#N and concentration of N on the surface were increased with increasing processing time and temperature. The corrosion resistance in 2-step low ...

Energy Technology Data Exchange (ETDEWEB)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positiond in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the ...

International Nuclear Information System (INIS)

General corrosion behavior of ALLOY 800 in high temperature water was studied in relation to its surface film structure. The surface film formed in water was found to decrease the corrosion rate of ALLOY 800. This film is composed of Ni ferrite, and can be obtained by oxidation in air or steam. Based on these results, air or steam oxidation treatment to inhibit Ni and Co release of ALLOY 800 into high temperature water is proposed. (author).

Energy Technology Data Exchange (ETDEWEB)

This report measured the rate of isothermal deposition of sub-micron particles of magnetite onto the surface of Alloy 800 at pH of 4.2-9.3 at Re=10,000 and a fluid temperature of 25C. Deposition is modelled as a two-step process, the transport of particles to the surface region followed by attachment to the surface.

Science.gov (United States)

This data set contains data from in situ infrared thermometer measurements ... Surface temperature was measured using an Apogee Infrared Thermometer from 23 ...

Science.gov (United States)

Jul 21, 1998 ... Additional roof surface temperatures were taken with a handheld "heat spy," an infrared thermometer to help calibrate the ATLAS thermal ...

Science.gov (United States)

... Data were obtained with a Heimann KT-19 infrared thermometer with a 2" field of view. ... Heimann KT-19 infrared thermometer ...

International Nuclear Information System (INIS)

... Industry, Material Science Research Laboratory, Yokosuka, Kanagawa (Japan)

KoreaScience (Korea)

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UK PubMed Central (United Kingdom)

The world's oceans contain a complex mixture of micro-organisms that are for the most part, uncharacterized both genetically and biochemically. We report here a metagenomic study of the marine planktonic...Full Text Available

International Nuclear Information System (INIS)

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.

Science.gov (United States)

The report gives an initial assessment of the feasibility of disposing of flue gas desulfurization wastes in mines and in the ocean. The purpose of the assessment was to evaluate environmental, technical, regulatory, and economic aspects of the use of such disposal sites. Availab...

Science.gov (United States)

A short account is given of the difficulties encountered in temperature measurement of boundary layers and a comparison of two types of thermometers, an infrared radiometer and mercury in glass thermometer. (Author)

KoreaScience (Korea)

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Science.gov (United States)

... 2004, Underwater Gliders for Ocean Research. Journal of the Marine Technology Society. Fiorelli, E., NE Leonard, P. Bhatta ...

Energy Technology Data Exchange (ETDEWEB)

A duplex surface treatment technique based on calorizing and plasma nitriding was developed to improve the wear and oxidation resistance of H13 steel at high temperatures. The effects of the relative thickness of the calorized layer to the depth of plasma nitriding on the wear and oxidation properties at temperatures up to 900 C were investigated in this work. High-temperature wear tests were performed at 500 C with dry conditions in open air using a ball-on-disk type tribotest machine. Isothermal oxidation tests were performed at 900 C for up to 100 h under controlled atmosphere. The results indicated that the specimens with a calorized layer as an intermediate phase between the surface duplex layer and the base metal showed higher wear and oxidation resistance than the specimens with a nitrided layer alone. During exposure to elevated temperatures, the ...

Energy Technology Data Exchange (ETDEWEB)

This spring, Newfoundland will send off a floating production, storage and offloading (FPSO) vessel to the offshore Terra Nova field. The Terra Nova will proceed southeast through Bull Arm, then northeast out of Trinity Bay, then heads southeast to the Jeanne d'Arc Basin on the Grand Banks. The Terra Nova is expected to produce 115,000 barrels of oil per day for six years, when it reaches full capacity. The consortium, headed by Petro-Canada as senior ownership partner and operator, built an environment protection program into every aspect of the project. Some of the features of the environment protection program include glory holes excavated on the ocean floor for the protection of production equipment from icebergs, to a flare stack on the platform, which has four legs to provide stability in rough seas. The FPSO was designed to withstand sea ice, icebergs, and severe winter storms. Flow lines are also protected, and in the event that a line is damaged, ...

Energy Technology Data Exchange (ETDEWEB)

The report was prepared for the IPCC by Working Group II. The remit of Working Group II was to describe the environmental and socioeconomic implications of possible climate changes over the next decades caused by increasing concentrations of greenhouse gases. The scenarios used include the following features: an effective doubling of atmospheric CO{sub 2} between now and 2025-2050; a consequent increase of global mean temperature of 1.5-4.5{degree}C; an unequal global distribution of the temperature increase; a sea level rise of 0.3 to 0.5m by 2050. The impacts of possible climate change were assessed for the following: agriculture and forestry; natural terrestrial ecosystems; hydrology and water resources; human settlements including the energy, transport and industrial sectors; human health; air quality and changes in UV-B radiation; oceans and coastal zones; seasonal snow cover; ice and permafrost. Further action is ...

Science.gov (United States)

Comparative patterns of equilibrium adsorption of argon on the surface of graphitized thermal carbon black (GCB) and the inhomogeneous surfaces of nongraphitized carbon black and silica at 77 and 87.3 K were considered. It was shown that argon acquires the properties of a special phase with a layered structure and exhibits two-dimensional phase transitions with the formation of crystal-like layers near the homogeneous surface of GCB even at a temperature exceeding the triple point. However, already at a distance of three-four molecular diameters from the surface, adsorbed argon behaves as a bulk phase in a weak external field. The defect surface of nongraphitized carbon black and the amorphous surface structure of silica destroy the longrange order of adsorbed argon and lower its solidification temperature. Therefore, ...

British Library Electronic Table of Contents (United Kingdom)

In this paper, the effects of surface mediation on the adsorption isotherm and isosteric heat of adsorption on a graphite surface were investigated, as the surface mediation is known to affect the intermolecular interaction of adsorbed molecules close to the surface. Kim and Steele (Phys. Rev. B 45 (11) (1992) 6226-6233) and others have assumed that the surface mediation is confined only to the first layer. This will be tested in this paper with a combined experimental and Grand Canonical Monte Carlo (GCMC) simulation of adsorption of argon on graphitized thermal carbon black (GTCB) over a range of temperatures (77-95.25K). By matching the simulation results against the experimental data, we have found that the surface mediation is extended up to the fourth layer, rather than only the firs...

Science.gov (United States)

In this paper we investigate the effects of surface mediation on the adsorption behavior of argon at different temperatures on homogeneous graphitized thermal carbon black and on heterogeneous nongraphitized carbon black surface. The grand canonical Monte Carlo (GCMC) simulation is used to study the adsorption, and its performance is tested against a number of experimental data on graphitized thermal carbon black (which is known to be highly homogeneous) that are available in the literature. The surface-mediation effect is shown to be essential in the correct description of the adsorption isotherm because without accounting for that effect the GCMC simulation results are always greater than the experimental data in the region where the monolayer is being completed. This is due to the overestimation of the fluid-fluid interaction between particles in the first layer close to the solid ...

Energy Technology Data Exchange (ETDEWEB)

The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. ...

Energy Technology Data Exchange (ETDEWEB)

One requirement of a thermophotovoltaic (TPV) radiator is to efficiently emit photons at high temperatures to TPV cells for conversion to electric power. Because many candidate radiator materials with adequate structural properties display low emissivity, coatings or other surface modifications are required for enhancement of emissivity. Six plasma sprayed coatings and one textured surface demonstrated adequate thermal stability and emittance values of 0.8 or greater. Promising attributes of modified surfaces are identified.

CERN Document Server

We investigate the influence of lunar-like satellites on the infrared orbital light curves of Earth-analog extra-solar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet. We use an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of the Earth while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g. via spectroscopy or visible-wavelength detection of specular glint from a surface ...

Energy Technology Data Exchange (ETDEWEB)

The volume examines the scientific interfaces and technological applications of physics. Twelve areas are dealt with: biological physics--biophysics, the brain, and theoretical biology; the physics-chemistry interface--instrumentation, surfaces, neutron and synchrotron radiation, polymers, organic electronic materials; materials science; geophysics--tectonics, the atmosphere and oceans, planets, drilling and seismic exploration, and remote sensing; computational physics--complex systems and applications in basic research; mathematics--field theory and chaos; microelectronics--integrated circuits, miniaturization, future trends; optical information technologies--fiber optics and photonics; instrumentation; physics applications to energy needs and the environment; national security--devices, weapons, and arms control; medical physics--radiology, ultrasonics, NMR, and photonics. An executive summary and many chapters contain recommendations ...

Energy Technology Data Exchange (ETDEWEB)

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, ...

Energy Technology Data Exchange (ETDEWEB)

Preliminary results of studies into penetrant testing at high surface temperature (up to 200 deg.C), are presented. Tests were performed to assess the effectiveness of red dye penetrants using Al and NiCr samples containing artificial as well as natural discontinuities. The test results will be used in due course to formulate a specification for non-destructive testing procedure qualification at non-standard (i.e. outside 16-52 deg.C) temperatures.

International Nuclear Information System (INIS)

Measurements of the Kapitza conductance to liquid helium II across the (100) surface of single crystals of copper are presented. The temperature range of these measurements was 1.6-- 2.1 K. The sample surfaces were subjected to several different treatments. Some surfaces were cleaned by low-energy argon ion bombardment, annealed in an ultrahigh-vacuum system, and preserved under vacuum until purified liquid helium was admitted. Other surfaces were intentionally damaged by machining and/or exposure to the atmosphere. The conductance after these latter treatments was found to be about a factor of three higher than that of the more ideally cleaned and annealed surfaces, and a significant difference in the temperature dependence of the conductance was also observed. Conductances were reproducible for similarly treated ...

International Nuclear Information System (INIS)

Efforts has been made to specify surface ozone production in photochemical reaction due to the high concentration of NO_x and photon rays. The secondary reactions has been considered via optical measurements using actinometry and pyranometry which was followed for photochemical reactions at high temperature and because of air pollutants due to the traffic load and because of the inversion in certain days. The concentration of surface ozone which was measured in Tehran city center was in the range of 24- 45 ppb in 1991-1992 and a higher concentration of 45-65 ppb was measured in 1999-2000. This high surface ozone concentration could cause a severe damage to biota, fauna and human health.

Energy Technology Data Exchange (ETDEWEB)

The Coastal Zone Sector of the Canadian Climate Impact and Adaptation Research Network (C-CIARN) was established to address concerns regarding climate change in coastal areas. Coastal zones are sensitive to increases in air, sea and ground temperatures as well as to variations in sea level, precipitation, ice thickness, and storm intensity. This report presents the results of a workshop which focused on how coastal communities will be affected by climate induced water level changes, particularly sea-level rise on ocean coasts and decreasing lake levels in the Great Lakes. The workshop addressed issues such as the effects of changing water levels on coastal infrastructure, utilities, community development, and the implications of changing water levels to human safety, cultural resources, tourism, and insurance. The workshop reviewed the current state of understanding on water level fluctuations resulting from climate change. It also identified ...

Energy Technology Data Exchange (ETDEWEB)

"What happens to conventional metals near the ocean?" you might ask the workers who are repairing the water tower at Jones Beach. They will tell you that both the tower's steel framework and copper roof show extensive corrosion from the salty air. To power future generations of cars, homes, utility plants, and even particle accelerators, unprecedented levels of efficiency will be needed. Such efficiency will require new unconventional alloys and composite materials that can also withstand high temperatures, intense radiation fluxes, high stresses, and other extreme conditions in highly corrosive environments that accelerate the aging and weakening of materials, as salty air weakens steel and copper. During the lecture, Simos will discuss the demands of next-generation energy systems and focus on the extreme conditions that materials used in these systems will perform under. He will also explain Brookhaven Lab's role in past, ...

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Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti{sub 2}N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 {mu}m{sup 2}/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen ...

International Nuclear Information System (INIS)

For the lifetime evaluation of plasma facing materials in fusion experimental machines, it is essential to investigate their surface behavior and their temperature responses during an off-normal event such as the plasma disruptions. An infrared thermometer with a sampling speed as fast as 1x10"-"6 s/data, namely, the high-speed infrared thermometer (HSIR), has been developed by the National Research Laboratory of Metrology in Japan. To evaluate an applicability of the newly developed HSIR on the surface temperature measurement of plasma facing materials, high heat flux beam irradiation experiments have been performed with three different materials under the surface heat fluxes up to 170 MW/m"2 for 0.04 s in a hydrogen ion beam test facility at the Japan Atomic Energy Research Institute. As for the results, HSIR can be applicable for measuring the surface ...

International Nuclear Information System (INIS)

A comparative assessment of five different heat transfer configurations for operation in compact heat exchangers is presented. The configurations under consideration are four standaed heat exchanger surfaces - two plain fin, an offset strip and a louvered fin geometry - and one surface with so called vortex generators for heat transfer augmentation. In the case of the standard surfaces, the basic performance characteristics in the form of heat transfer and friction data versus the Reynolds number have been taken from published experimental results. In the case of the vortex generator surface, the performance characteristics have been derived from a numerical prediction of the flow and temperature field in a closely spaced parallel plate channel with vortex generators in the form of delta wings mounted on the channel walls. In comparison to the plain fin surfaces ...

International Nuclear Information System (INIS)

By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning ...

International Nuclear Information System (INIS)

The transformation of Pd/Si to Pd_2Si/Si is studied using Auger electron spectroscopy over a wide temperature range of 370-1020 K. The Pd film gets totally converted to Pd_2Si upon annealing at 520 K, and beyond 570 K, Si starts segregating on the surface of silicide. It is found that the presence of surface oxygen influences the segregation of Si. The time evolution study of Si segregation reveals that segregation kinetics is very fast and the segregated Si concentration increases as the temperature is increased. Scanning electron microscopy measurements show that Pd_2Si is formed in the form of islands, which grow as the annealing temperature is increased.

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The initial growth process and surface structure of thin Pd(silicide) films on clean Si(111)-7x7 surfaces have been studied by low energy ion scattering (ISS) and LEED-Auger techniques. Considerable reaction between Pd and Si at room temperature is observed to extend up to 25 ML thickness of deposited Pd. Heat treatment of the room temperature film produced epitaxial silicide Pd/sub 2/Si(0001) films covered with the accumulated elementary Si layers of 1-2 ML thickness. Deposition of 1/3 ML Pd onto a heated substrate gives a Pd-embedded ordered surface of Si(111)-..sqrt..3x..sqrt..3R30/sup 0/, the feature being similar to the cases of Ag, Au/Si(111) systems.

International Nuclear Information System (INIS)

Conventional plasma carburizing or nitriding for austenitic stainless steels results in a degradation of corrosion resistance. However, a low temperature plasma surface treatment can improve surface hardness without deteriorating the corrosion resistance. The 2-step low temperature plasma processes (the combined carburizing and post nitriding) offers the increase of both surface hardness and thickness of hardened layer and corrosion resistance than the individually processed low temperature nitriding and low temperature carburizing techniques. In the present paper, attempts have been made to investigate the influence of the introduction of Ar gas (0#approx#20%) in nitriding atmosphere during low temperature plasma nitriding at 370 .deg. C after low temperature plasma carburizing at 470 .deg. C. All ...

Energy Technology Data Exchange (ETDEWEB)

Separate abstracts were prepared for 62 papers in this volume of conference proceedings. Two other papers were previously abstracted for EDB. (LEW)

Science.gov (United States)

Deforestation farther inland causes delayed reactions. When roots no longer hold soil in place, it ends up muddying streams, rivers, and coastal waters. ...

Science.gov (United States)

The company reports that with the help of outside companies, they completed all major fixes including high-voltage transmission lines to neighborhood ...

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... DV Holliday BAE SYSTEMS Applied Technologies, IES/ITS Analysis and Applied Research 4545A Viewridge Avenue San Diego, CA 92123 phone ...

Science.gov (United States)

Not Available

Science.gov (United States)

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

Science.gov (United States)

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

International Nuclear Information System (INIS)

Full text: The surface properties of poly (tetrafluoroethylene) (PTFE) are changed by the exposure to synchrotron radiation (SR). We succeeded in controlling the wettability of the PTFE surface from hydrophobic to hydrophilic by varying the substrate temperature during the SR irradiation and found that the wettability was ascribable to microstructure and chemical composition of surface.In these previous works, oxygen atoms were found to inhabit on the hydrophobic surface of PTFE. In this study, we investigated the surface modification of PTFE from the SR exposure experiment under the O_2 gas atmosphere. The SR exposure to the PTFE sheet was carried out at beamline 6 (BL6) of the New- SUBARU. The PTFE sheet was irradiated to the white beam, ranging 50-1000 eV at BL6 at room temperature. The gas cell was mounted at the irradiation chamber. The ...

Energy Technology Data Exchange (ETDEWEB)

This work was initiated to examine the effect of frequency and treatment temperature on the formation of nitrided layers and surface characteristics during plasma nitriding. Plasma nitriding experiments were performed with 316L austenitic stainless steel at the temperatures 400 .deg. C and 500 deg. C using a pulsed d.c. plasma with various frequencies in an atmosphere of N{sub 2}-H{sub 2} gas mixture. The microstructure and thickness of the nitrided layer and morphology of the nitrided surface were investigated using OM, SEM, XRD, EDS and AFM. XRD patterns revealed that the surface layer formed at 400 deg. C consisted of S phase only and CrN+Fe{sub 4}N nitrides at 500 .deg. C and no change of phase composition with frequency was observed. The compound layer thickened slightly with increased frequency. Also, the surface roughness increased as the frequency of the ...

International Nuclear Information System (INIS)

DZ4 substrates were coated with NiCoCrAlY by plasma spray and subsequently treated by high current pulsed electron beams(HCPEB) of different parameters. The surface microstructure, phase structure and high temperature oxidation resistance were studied. It has been shown that as a result of the HCPEB treatment the loose and rough structure remelted and the surface became smooth. Smooth microregion, craters and cracks appeared on the surface. The ?' phase manifolded and there was no visible thermal stress. The oxidation test at 900 degree C for 100 h showed that a more compact and successive ?-Al_2O_3 scale was formed on the surface of the samples after HCPEB irradiation, which improved the oxidation resistance of the NiCoCrAlY coatings obviously. (authors)

UK PubMed Central (United Kingdom)

A controlled fire burner was constructed where various natural vegetation species could be used as fuel. The burner was equipped with thermocouples to measure fuel surface temperature and used as a...Full Text Available

Science.gov (United States)

The catalytic effects of copper-aluminium-magnesium oxides in the oxidative coupling of phenylethyne is described. The importance of surface properties as a redox site are discussed.

Energy Technology Data Exchange (ETDEWEB)

A new theory has been developed to calculate the steady state temperature profile in a cylindrical sample positioned along the entire axis of a cylindrical microwave cavity. Temperature profiles were computed for alumina rods of various radii contained in a cavity excited in one of the TM{sub 0n0} modes with n = 1, 2 or 3. Calculations were also performed with a concentric outer cylindrical tube surrounding the rod to investigate hybrid treating. The parametric studies of the total sample center and surface temperatures were performed as a function of the total power transmitted into the cavity. Also, the total hemispherical emissivity was varied at boundaries of the rod, surrounding tube, and cavity walls. The results are discussed in the context of controlling the average rod temperature and the temperature distribution in the rod during microwave processing.

International Nuclear Information System (INIS)

A LiF crystal analyzer has been used to measure phonon creation events when a low energy He beam scatters from a Cu(001) surface at low temperature (16 "0K). As only phonon creation events were observed, the inelastic scattering was subspecular. Atom parallel momentum gain and loss events were observed and both bulk and surface modes contributed to the inelastic scattering. An elastic component of scattering was observed over a wide angular range.

Energy Technology Data Exchange (ETDEWEB)

In addition to ceramics, alloys such as tool steel and nickel- and iron-based superalloys are being considered for high temperature applications such as missile bearings and low heat rejection engines. Studies were made to lubricate a nickel-based superalloy at 500{degrees}C, by using a vaporized aryl phosphate ester, at a concentration of 0.1% in air. From deposition and wear studies it was found that it was impossible to form a good polymeric coating on the superalloy surface. Energy dispersive X-ray analyzer (EDXA) analysis showed that this was due to minute quantities of aluminum in the alloy segregating to the surface, upon being heated to 500{degrees}C, forming a passive oxide coating. It was necessary to activate the surface, in order to lubricate the material successfully. A method of activation by electrodepositing the surface with a layer of iron oxide was developed. Once ...

International Nuclear Information System (INIS)

Design layout of horizontal steam generator (SJ) with a special feedwater heating surface (by a surface water economizer), designated for NPPs with WWER-1000 reactors, is suggested. The design enables to decrease sharply the difference between the temperatures of saturation and feedwater. Blowdown outlet is organized against PG face, which increases the efficiency of flowing. The suggested layout enables to decrease thermal stresses in structural units and PG metal content, as compared to the PGV-1000 steam generator.

International Nuclear Information System (INIS)

It is shown that the section of the energy surface corresponding to the longitudinal mode by the principal xy-plane for the A-15 compounds will degenerate into four points at the corners of a square at very low temperatures in the cubic phase. When the quasi-shear mode propagating along the (110) direction becomes soft, simultaneously the longitudinal mode will exhibit unusually high phonon focussing. (author).

Energy Technology Data Exchange (ETDEWEB)

Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)

Energy Technology Data Exchange (ETDEWEB)

In situ Auger sputter depth profiles of saturation implants of 3 keV N/sub 2//sup +/ in silicon at room temperature exhibit a sharp peak in the nitrogen concentration in the outermost layers, followed by a monotonic decrease. No broad plateau was observed. The energy of the Auger line corresponding to the Si(2p) core electron excitation, monitored throughout the profiling, exhibits a chemical shift of up to 7 eV at the surface peak concentration. Inert gas ion post-bombardment of unsaturated implants significantly modifies the profile, and supports the suggestion that the surface peak arises through radiation enhanced diffusion of implanted atoms.

Energy Technology Data Exchange (ETDEWEB)

Directionally solidified nickel-based superalloy DZ4 is an important structural material. However, the grinding burn occurs in grinding processes has hindered the grinding efficiency and dimensional accuracy. This paper investigates the grinding mechanism of this new type of superalloy based on the systematical analyses of variable characteristics of the grinding force, grinding temperature, topography of ground surface, hardness distribution of surface layer, as well as morphology of surface layer from a metallographical point of view. The results will be beneficial to grinding the superalloy with high efficiency and high precision. (orig.)

Science.gov (United States)

We model nongraphitized carbon black surfaces and investigate adsorption of argon on these surfaces by using the grand canonical Monte Carlo simulation. In this model, the nongraphitized surface is modeled as a stack of graphene layers with some carbon atoms of the top graphene layer being randomly removed. The percentage of the surface carbon atoms being removed and the effective size of the defect (created by the removal) are the key parameters to characterize the nongraphitized surface. The patterns of adsorption isotherm and isosteric heat are particularly studied, as a function of these surface parameters as well as pressure and temperature. It is shown that the adsorption isotherm shows a steplike behavior on a perfect graphite surface and becomes smoother on nongraphitized surfaces. Regarding ...

Energy Technology Data Exchange (ETDEWEB)

Separate abstracts were prepared for 20 papers in this conference report and includes all papers in the ''engineering'' section (program E). Ocean thermal energy conversion (OTEC), moorings, cables, corrosion protection, corrosion testing, coatings, offshore platforms, pipelines, OTEC models and pilot plants, and energy transfer are topics discussed.

Wastenet

...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 ...

British Library Electronic Table of Contents (United Kingdom)

Abstract A large number of massive stars are known to rotate rapidly, resulting in a significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass-loss is temperature-dependent, so rapid rotation produces a variation in the mass-loss and angular momentum loss rates across the surface of the star, which is expected to affect the evolution of rapidly rotating massive stars. In this work, we use zero-age main-sequence (ZAMS) stellar models to investigate the two-dimensional effects of rotation on stellar mass-loss, using two common prescriptions for radiatively driven mass-loss. The associated loss of angular momentum from these models is also considered. Using 2D stellar models, which give the variation in surface parameters as a function o...

Science.gov (United States)

The change in the energy flow on land used for brown coal mining is examined. Terrain mapping was used to obtain land use data for a 14 km{sup 2} mining area and its surroundings. The focus is on the proportion of incident solar energy that is changed to latent heat during evapotranspiration. Each land use unit was assigned an average value for evapotranspiration for the growing season. Satellite data of surface temperature and surface wetness values show incident radiation converted to heat. Relationships between evapotranspiration and surface temperature and between wetness index and evapotranspiration were verified. The results confirm the hypothesis that changes in land use can have a significant effect on total average evapotranspiration. 18 refs., 5 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

Room air quality and thus thermal comfort for the occupiers in closed spaces depend on several factors: temperature and humidity of the air, temperature of the surrounding surfaces, content of foreign matter of the air, acoustical perceptions, electric fields and ions as well as colours and light. Air humidification, cleaning and ionization largely contributes to improved room air quality. The article goes into problems of too dry and polluted air as well as into measures with which these problems can be solved. (BWI).

Energy Technology Data Exchange (ETDEWEB)

The thermal accommodation coefficients of helium, neon, argon, hydrogen and deuterium have been measured in the temperature range of 77-340 K on the surface of a graphitized carbon filament. The dependence of the accommodation coefficient upon the molecular weight as well as the temperature of measurement, and the conversion from orthohydrogen to parahydrogen, have been discussed.

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to identify the radiative heat transfer augmentation by a coaxial cylinder introduced in the infinite cylindrical pipe enclosing a participating gas. The gas is either a mixture of water vapor and carbon dioxide or gray. The gas is assumed to be homogeneous at a constant temperature, and has a refractive index of unity. All of the surfaces are opaque and gray, diffusely emitting and reflecting at a constant temperature. The effect of system diameter, diameter ratio, wall emittances, gas and surface temperatures, mixture component on heat transfer augmentation are studied by using the zone method with participating gas radiative properties evaluated from the weighted sum of gray gases model. From the radiative equilibrium condition, the installed wall temperature is formulated and calculated by the iteration method. If the medium is a ...

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This thesis details the first direct ultrafast measurements of the dynamic thermal expansion of a surface and the temperature dependent surface thermal diffusivity using a two-color reflection transient grating technique. Studies were performed on p-type, n-type, and undoped GaAs(100) samples over a wide range of temperatures. By utilizing a 90 fs ultraviolet probe with visible excitation beams, the effects of interband saturation and carrier dynamics become negligible; thus lattice expansion due to heating and subsequent contraction caused by cooling provided the dominant influence on the probe. At room temperature a rise due to thermal expansion was observed, corresponding to a maximum net displacement of {approximately} 1 {Angstrom} at 32 ps. The diffracted signal was composed of two components, thermal expansion of the surface and heat flow away from the ...

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The depletion of stratospheric ozone is caused by chlorine species formed in heterogeneous processes on the surfaces of polar stratospheric cloud (PSC) particles. For studying local PSC formation processes in the Arctic a temperature lidar receiver was developed that makes use of the rotational Raman method, the only lidar technique for measuring atmospheric temperature profiles not perturbed by the presence of aerosols or cloud particles. The receiver was implemented in the mobile GKSS Raman lidar and transferred to Esrange (67.9 N, 21.1 E) near Kiruna in northern Sweden in winter 1997/98. Temperature data measured between January 22 and February 6, 1998, are presented and compared to model data analyzed by the European centre for medium-range weather forecast. Local temperature profiles are studied in three cases of type-Ib PSCs. This type is characterized by a low depolarization ...

CERN Document Server

We present first worldline numerical results for the nontrivial interplay between geometry and temperature dependencies of the Casimir effect. We show that the temperature dependence of the Casimir force can be significantly larger for open geometries (e.g., perpendicular plates) than for closed geometries (e.g., parallel plates). For surface separations in the experimentally relevant range, the thermal correction for the perpendicular-plates configuration exhibits a stronger parameter dependence and exceeds that for parallel plates by more than an order of magnitude at room temperature. This effect can be attributed to the fact that the fluctuation spectrum for closed geometries is gapped, inhibiting the thermal excitation of modes at low temperatures. By contrast, open geometries support a thermal excitation of the low-lying modes in the gapless spectrum already at low ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Dynamic testing of a phosphoric acid-based high temperature PEM fuel cell shows a peculiar phenomenon. A certain current loss is observed after temperature cycling at constant voltage. This loss is incidentally recovered by applying a cell voltage spike to open circuit voltage. Experimental investigations into temperature, cell voltage, and ageing effects show that this phenomenon might occur due to the orientation of the adsorbed phosphate species on the platinum catalyst surface. Along with some supporting literature and experimental results, a hypothesis is presented in order to explain this occurrence. Phosphoric acid adsorption hysteresis on platinum catalyst due to temperature cycling could cause the temporary cell current loss. Electrode potential-dependent molecule symmetr...

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This experiment is carried out in the series of the investigation on the damage mechanism of carbon steel. In this paper, the damage situation is considered by structure observations. The test were carried out in 600degC-1200degC temperature range, in blowing an argon gas. The reagents are Na{sub 2}O, Na{sub 2}O{sub 2} and NaOH. From structure observations, the holes are observed on the surface of iron-base material in some test conditions. This result is indicated that the selective reaction occurs. The selective reaction is more obvious as the time exposed to the high temperature is longer. It is considered that the selective reaction occurs after the chemical reaction between iron-base material and sodium compound. The areas, in which Mn-concentration is higher, are observed in products on the surface of specimen. (author)

Energy Technology Data Exchange (ETDEWEB)

The spontaneous precipitation of calcium sulfate in supersaturated solutions over the temperature range between 25.0 and 80.0 C was investigated by monitoring the solution specific conductivity during desupersaturation. From measurements of the induction times preceding the onset of precipitation the surface energy of the forming solid, identified as gypsum, was found between ca. 12 and 25 mJ/m{sup 2} for the temperature range between 80.0 and 25.0 C, respectively. Kinetics analysis showed that over 50 C it is possible that anhydrous calcium sulfate is forming as a transient phase converting into the more stable calcium sulfate dihydrate. The linear dependence of the rates of precipitation on the relative solution supersaturation suggested a mechanism according to which the growth units are integrated into the active sites of the supercritical nuclei by surface diffusion. According to the morphological ...

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Cold spray was employed as a novel low temperature approach to deposit titanium dioxide (TiO{sub 2}) photocatalytic film. The film microstructure was characterized using X-ray diffraction and scanning electron microscopy. The photocatalytic performance was examined through acetaldehyde degradation under ultraviolet illumination. Results showed that TiO{sub 2} film was successfully deposited on substrate surface through cold spray. The film thickness reached up to 15 {mu}m. The film presented a rough surface and porous structure. Owing to the low temperature of spray powder, no phase and particle size changes occurred to TiO{sub 2} during deposition. It was found that the cold-sprayed TiO{sub 2} film was active for photodegradation of acetaldehyde.

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A method is proposed for the quantitative high-temperature isolation of /sup 111/In from silver irradiated by ..cap alpha..-particles into a gas phase containing a mixture of HCl and H/sub 2/O with a total pressure of about 3 Pa for these gases. It is shown that the indium evolved into the gas phase probably occurs in the form of at least three compounds, viz.., the trichloride, monochloride, and oxychloride, which have adsorption temperatures on quartz of around 385, 475, and 655 K, respectively. All these compounds are readily washed from the surface of quartz apparatus by a weak (0.05 M) solution of hydrochloric acid.

Energy Technology Data Exchange (ETDEWEB)

The thesis describes work undertaken as part of a larger remote sensing based project which aims to detect, measure and monitor coal fires in two test areas in northern China. The first main topic addressed in this thesis is the detection of fires using several different thermal remote sensing data sets. The synergistic use of the different data sets is emphasised. The second major part of the thesis deals with thermal modelling of the coal fires. Three different models are developed, which allow a fire's depth, temperature, extent, total heat output and rate of movement to be determined. The models are tested both in the laboratory and using various field data sets. A model based on the assumption that the fire is a point heat source and that the temperature distribution around it is spherically symmetrical is shown to be the most effective. A simpler, one-dimensional coal fire model and a model based on the finite element method are ...

International Nuclear Information System (INIS)

SiC has been considered as a primary candidate material for a first wall component in future fusion reactor because it has been claimed that SiC has excellent high-temperature properties, good chemical stability and low activation. However, the behavior of tritium on SiC has not been discussed yet. In this study, tritium trapping capacity on the surface of SiC was experimentally obtained at the temperature range of 25-800 deg. C in consideration of tritium trapping to the experimental system. The capacity, which was independent of the water vapor pressure in the gas phase and the temperature, was determined as about 10"6 Bq/cm"2. The isotope exchange reaction rate between tritiated water in a gas phase and hydrogen on the surface was quantified at the temperature of 25, 500 and 700 deg. C in consideration of the behavior of tritium trapping at change of ...

International Nuclear Information System (INIS)

In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 #mu#m thick nitride compound layer was formed in surface region and the same thick carbide compound ...

Energy Technology Data Exchange (ETDEWEB)

Sulfuric acid hydrogen peroxide mixtures (SPM) are commonly used in the semiconductor industry to remove organic contaminants from wafer surfaces. This viscous solution is very difficult to rinse off wafer surfaces. Various rinsing conditions were tested and the resulting residual contamination on the wafer surface was measured. The addition of small amounts of a chemical base such as ammonium hydroxide to the rinse water has been found to be effective in reducing the surface concentration of sulfur and also mitigates the particle growth that occurs on SPM cleaned wafers. The volume of room temperature water required to rinse these wafers is also significantly reduced.

Science.gov (United States)

The summertime tropical cyclogenesis rate per unit area in the eastern Pacific ocean is arguably higher than in any other location in the world. Many if not most of these cyclones form from African easterly waves which cross Central America into the Pacific. Of order 25% of these waves intensify into cyclones. A significant fraction of east Pacific tropical cyclones undergoes landfall on the Mexican coast. Those which do not, generally dissipate over cold ocean waters north of the east Pacific intertropical convergence zone, often not far from land. The layer of warm ocean water which supports the development of east Pacific cyclones is unusually shallow and is structured by anticyclonic vortices which form by various processes and propagate slowly to the west. These vortices locally deepen the oceanic mixed layer and support stronger convection than their surroundings, possibly promoting ...

International Nuclear Information System (INIS)

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 ...

Science.gov (United States)

On-orbit spectral calibration of hyperspectral imaging data is a key step for quantitatively analyzing them. Like the atmospheric correction, accurate spectral calibration is very necessary for improved studies of land or ocean surface properties. Based on the previous literatures, a new method which coupled an optimization algorithm was developed to simultaneously retrieve the central wavelength and the full width at half maximum (FWHM) of the hyperspectral sensor without needing the in situ reflectance spectra. Firstly, the Hyperion data set simulated using MODTRAN4 with the Hyperion spectral specification was used to test the new method, and the results indicated that the maximum error was less than 0.1 and 0.7 nm for central wavelength and FWHM respectively when the spectral shift is 5 nm. Then the algorithm was applied to the Hyperion data acquired on May 20, 2008 over Heihe River Basin and it was iteratively performed for each detector of ...

Energy Technology Data Exchange (ETDEWEB)

The atmosphere and the biosphere are inherently coupled to one another. Atmospheric surface state variables such as temperature, winds, water vapor, precipitation, and radiation control biophysical, biogeochemical, and ecological processes at the surface and subsurface. At the same time, surface fluxes of momentum, moisture, heat, and trace gases act as time-dependent boundary conditions providing feedback on atmospheric processes. To understand such phenomena, a coupled set of interactive models is required. Costs are still prohibitive for computing surface/subsurface fluxes directly for medium-resolution atmospheric general circulation models (AGCMs), but a technique has been developed for testing large-scale homogeneity and accessing surface parameterizations and models to reduce this computational cost and maintain accuracy. This modeling system potentially ...

British Library Electronic Table of Contents (United Kingdom)

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...

Energy Technology Data Exchange (ETDEWEB)

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 ...

Science.gov (United States)

The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg U/m{sup 3} 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 m{sup 2} 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.

Science.gov (United States)

Silicon carbide (SiC) based electronic devices are of great importance for applications under the condition of high temperature, high power and high radiation. Schottky diodes of Palladium/SiC are good candidates for hydrogen and hydrocarbon gas sensors at elevated temperature. The detection sensibility of the diodes has been found heavily temperature dependent. In this work, the electrical and chemical properties of Pd/SiC Schottky contacts were studied by XPS and AES at different annealing temperatures. Schottky diodes were made by depositing ultra-thin palladium films onto a silicon carbide substrate. No significant change in the Schottky barrier height of the Pd/SiC contact was found in the temperature range of 300-673K. Palladium diffusion into SiC and the formation of palladium silicides were observed at room temperature and became significant at 300^oC ...

Energy Technology Data Exchange (ETDEWEB)

The temperature effect on corrosion behaviors of PbCaSnCe alloy in 4.5 M H{sub 2}SO{sub 4} solution was investigated by using potentiodynamic curve, electrochemical impedance spectra (EIS), Mott-Schottky plot and photocurrent response methods. It was found that PbCaSnCe alloy was in passive state in sulfuric acid solution, a passive film can be formed on alloy surface. The compositions of passive films formed at 0.9 V for 2 h under different temperatures were detected by X-ray photoelectron spectroscopy (XPS). The results showed that the film resistance and the transfer resistance decreased with the increment of the solution temperature. Mott-Schottky analysis and the photocurrent response revealed that the passive film exhibited n-type semi-conductive character, the donor density of the passive film decreased with increasing the solution temperature. Photocurrent response revealed ...

British Library Electronic Table of Contents (United Kingdom)

In this paper we review and classify the various patterns of isosteric heat versus loading for adsorption of gases on graphitised thermal carbon black at temperatures ranging from below the 3D triple point to temperatures above it, but less than the 3D critical point. We have identified the features of heat curve and highlighted the microscopic origin of these features. The patterns vary with temperature and with the relative strength of the fluid-fluid interaction and solid-fluid interaction. For simple adsorptives (by simple we meant there is no strong association between fluid particles), the heat curve is typified by fluid-fluid attraction and layering phenomena. For adsorptives showing strong association such as water, ammonia and methanol, the heat curve essentially begins below the ...

British Library Electronic Table of Contents (United Kingdom)

In the present work, the plasma nitriding behavior of a nickel based dental alloy was investigated. Plasma nitriding experiments carried out under constant gas mixture (15% H2?85% N2) for different process parameters including time (4, 6, 10, and 20?h) and temperature (400, 450, 500, and 550??C). Depending on nitriding parameters, it was found that triple or double layers formed on the surface of the samples. Increasing of treatment time and temperature has resulted in a double layer. ?N1 layer was in formed all nitrided samples. However, ?N2 layer is formed only at low temperatures and in short times. Layer growth of nickel based alloys increases until a critical time or a critical temperature reached. Above these critical values, it is observed that the layer thickness decreases. It was ...

International Nuclear Information System (INIS)

In a vacuum insulator, the narrow electron beam emitted from the cathode impinges on the anode and raises its temperature and also may produce high thermal stress. This high thermal stress, in conjuction with the surface electrostatic pressure may rupture the surface and detach particles from it. In this thesis, the interaction of high energy electron and laser beams with metals and semiconductors is investigated. The differential equations governing the physical processes involved in the interaction are solved by the finite element method. Effects of beam penetration into the material, variable beam reflectance at the surface, finite beam size and dependence of material properties on temperature are accounted for. The two-phase moving boundary problem, also known as the Stefan problem, is solved by an enthalpy formulation of the heat equation. Material deformation by thermal ...

Energy Technology Data Exchange (ETDEWEB)

The influence of surface oxides of variable composition and nonstoichiometry formed at high temperatures in air on the general corrosion resistance of ferritic chromium steel type 08H17T (Fe-17Cr-1Ti) in weak sulfuric acid has been studied. Anodic passive films formed on steel with different pretreatments have also been examined. The surface oxide of nearly stoichiometric composition formed at 300 C provides for the passive state of steel in sulfuric acid despite its depletion by chromium when compared with that for nonstoichiometric Cr-enriched oxide formed at 600 C. The dissolution and transformation of nonstoichiometric thermal surface oxide in sulfuric acid appear to take place through defect sites, {minus}Fe{sup 2+} ions, and oxygen vacancies of the n-type conductor. The passive film formed on the nonstoichiometric oxide film, which had been produced at 600 C, was found to be more susceptible to ...

International Nuclear Information System (INIS)

Single crystal cubic boron nitride (cBN) was heteroepitaxially grown on a seed crystal of diamond under static high pressure and high temperature at 5.5GPa and 1,600--1,700 C, respectively, for 10--100 hour. A temperature gradient method was employed for the crystal growth by using lithium boron nitride as a solvent. Initial growth feature of cBN crystal was found on the diamond seed surface after the growing time of 10 minutes. The nucleation sites of the crystals seem to be near the etch pits on the diamond surface which were introduced by the surface dissolution by the solvent for cBN growth. Two types of growth features, island and step growth were typically shown on the surface. It can be seen that grown crystal appearing as a (111) nitrogen face was exhibited with the step growth feature, while the (11n) face exhibited the island growth feature. ...

Science.gov (United States)

The evolutionary history of the reef fish genus Naso (F. Acanthuridae) was examined using a complete species-level molecular phylogeny of all recognized (19) species based on three loci (one nuclear ETS2 and two mitochondrial 16S, cyt b). This study demonstrates that distinct foraging modes and specialized body shapes arose independently at different times in the evolutionary history of the genus. Members of the subgenus Axinurus, characterized by a scombriform morphology, caudal fin structure and pelagic foraging mode, were consistently placed basal to the remaining Naso species, suggesting that pelagic foraging is plesiomorphic and benthic foraging derived in this genus. We used a genus-level phylogeny (nuclear marker, ETS2), which included several taxa from all other acanthurid genera, to obtain a range of age estimates for the most recent common ancestor of the genus Naso. These age estimates (range of 52-43.3 MY) were then used to estimate divergence times (by nonparametric rate ...

International Nuclear Information System (INIS)

CNPT-3 is the laboratory designation of a strain of bacteria that reproduces best at deep-sea pressures. It was isolated from a sample collected at a 5800 m depth of the Pacific Ocean. This isolation was achieved from a sample that had been retrieved without warning. This year we demonstrated that there are similarly behaving bacteria that can be isolated from samples even when retrieved with decompression. The purpose of this project was to define the temperatures and pressures over which CNPT-3 can exist and function. (1) At 2"0C CNPT-3 is eurybathic from about 1000 to 6500 m, as judged from an only slightly pressure dependent generation time. (2) CNPT-3 is unquestionably barophilic at 2"0C, with doubling times of 9 hours at 580 bars and over 18 hours at 1 bar. (3) At 10"0C, reproduction is adversely affected at 1 bar to the extent that CNPT-3 becomes obligately barophilic at 10"0C. Yet reproduction is enhanced above 280 bars and occurs with ...

Energy Technology Data Exchange (ETDEWEB)

The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces that are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate triode sputtering methods are discussed. In addition to substrate temperature, the bcc-to-beta phase ratio in sputtered tantalum coatings is shown to be sensitive to other substrate surface effects.

Science.gov (United States)

The MgF{sub 2} monocrystals were irradiated at room temperature with 390 keV B{sup +} ions up to the fluence of 10{sup 16} cm{sup -2}. The irradiated samples were (isochronally and isothermally) annealed in high vacuum at the temperatures 200 deg. C, 300 deg. C, 400 deg. C, 500 deg. C, 600 deg. C and 700 deg. C for the times ranging from 2-100 hours. After each annealing step, the boron depth distribution was determined using the neutron depth profiling technique. As implanted, the depth distributions of boron exhibited standard Gaussian-like forms, but the evaluated profile parameters, R{sub P} = 960 nm and {delta}R{sub P} = 140 nm, were higher than those calculated using the SRIM code (R{sub P} = 870 nm and {delta}R{sub P} = 115 nm). Annealing at temperatures up to 400 deg. C did not change the depth profiles. Annealing at 600 deg. C, however, led to a one-way gradual transfer of the boron atoms from the site of ...

Energy Technology Data Exchange (ETDEWEB)

Results are presented from a numerical model of the steady-state energy transfer in molten-salt-in-tube solar cavity receivers that includes convective energy transfer at a local (spatially resolved) level. Molten salt energy absorption and gray radiative transfer between all cavity surfaces are also included. This model is applied to the Molten Salt Subsystem Component Test Experiment (MSS/CTE) cavity receiver. Results for this receiver indicate the global (entire cavity) receiver thermal efficiency is invariant within a few percent to most parameters investigated, although front surface temperatures of the nonabsorbing walls vary considerably, and are particularly sensitive to the type of convective submodel used. Absorption efficiencies indicate the effects of the cavity enclosure environment. For all conditions investigated, tube inner wall temperatures remain under 855 K, ensuring that the salt ...

Energy Technology Data Exchange (ETDEWEB)

Stainless steels can be nitrided at temperatures {<=}400 C to increase their hardness and wear resistance without a decreasing of their excellent corrosion resistance. Structure and properties of the surface layers produced by plasma nitriding and plasma immersion ion implantation in this temperature range were tested. There are negligible differences in the structure of the produced surface layers in spite of different interaction principles of the used technologies. However there are clear differences between the case of different steels. The case of ferritic chromium steels mainly consists of {epsilon}-nitride. Whereas the cases of austenitic and ferritic austenitic steels are characterized by expanded austenite. The corrosion resistance of the steels is reduced by nitriding only, if evident CrN-formation occurs. (orig.) 11 refs.

Energy Technology Data Exchange (ETDEWEB)

We present a 1-D heat transfer, melting, vaporization and resolidification model describing the interaction of a scanning continuous-wave laser with a metal surface wherein the beam power is constant. A physical model based on the Stefan problem is developed with appropriate boundary conditions. The effects of processing parameters on process variables are investigated numerically by varying beam diameters, scan speeds and substrate temperatures for Nickel. Relations are derived for the times to initiate melting, to initiate vaporization, to reach maximum melting depth, for melting-resolidification, and for maximum melting and vaporization depths. Surface temperatures are compared with approximate closed form solutions. (Author)

Energy Technology Data Exchange (ETDEWEB)

Mass transfer to a wall of a horizontal rectangular channel reactor was investigated by the limiting current technique for Reynolds numbers ranging from 200 to 32000. Overall mass transfer coefficients at various mass transfer surface angles were obtained while the reactor was operated under isothermal and non-isothermal conditions. Dimensionless correlations were developed for isothermal flows from 25 to 55{sup o}C and for non-isothermal flows with applied temperature differences up to 30{sup o}C. In the laminar flow range natural convection dominated, but under turbulent conditions combined natural and forced convection prevailed. Mass transfer was approximately doubled under optimum selection of channel surface rotation, temperature gradient and flow rate. (author)

Energy Technology Data Exchange (ETDEWEB)

This research investigated the influence of stearic acid on the injection molding of alumina, by varying the concentration of stearic acid. The interaction between stearic acid and alumina was identified using transmission infrared spectroscopy, indicating stearic acid preferentially adsorbed onto the alumina powder surface. In addition to slightly modifying the intrinsic binder viscosity, stearic acid adsorbed onto the powder surface changed the flow behavior of the mixtures from dilatant flow to pseudoplastic flow at low temperatures. As a result, inhomogeneous distribution of binder in the injection-molded parts was minimized with increased stearic acid concentration. However, the possibility of forming bubbles in the mixtures arising from vaporization of stearic acid was enhanced. Additionally, the binder burnout temperature range was broadened with the increase of stearic acid concentration.

CERN Document Server

Motional heating of ions in micro-fabricated traps is a challenge hindering experimental realization of large-scale quantum processing devices. Recently a series of measurements of the heating rates in surface-electrode ion traps characterized their frequency, distance, and temperature dependencies, but our understanding of the microscopic origin of this noise is still vague. In this work we develop a theoretical model for the electric field noise which is associated with a random distribution of adsorbed atoms on the trap electrode surface. By using first principle calculations of the fluctuating dipole moments of the adsorbed atoms we evaluate the distance, frequency and temperature dependence of the resulting electric field fluctuation spectrum.Our theory calculates the noise spectrum beyond the standard scenario of two-level fluctuators, by incorporating all the relevant vibrational states. The ...

Energy Technology Data Exchange (ETDEWEB)

The leached glass is subject to leachant attack and results in surface layer alteration which greatly affects the corrosion progress of glass forms. This work studied the composition change, precipitation, pitting corrosion as well as surface layer break and spallation of the leached glass forms. 6 conclusions can be made: 1. The extent of surface layer alteration is related to many factors such as temperature, pH, leachant chemistry, flow rate and leach duration, etc. 2. The alkali element Na is seriously depleted and the elements like U.Ti,Fe, Ca and Mg are enriched in the surface layer. The influence of media has such order: Fe{sub 2}O{sub 3} > Na-bentonite > Zeolite. 3. The precipitate formed in leach test for 56 days at 90 {infinity}C is mostly amorphous, but after 91 days has crystallized. There is K - Ca - Al - Si crystal,the amount of Al, K and Si is ...

UK PubMed Central (United Kingdom)

BackgroundDinoflagellates are unicellular, often photosynthetic protists that play a major role in the dynamics of the Earth's oceans and climate. Sequencing of dinoflagellate nuclear...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundFood supply from the ocean is constrained by the shortage of domesticated and selected fish. Development of genomic models of economically important fishes should assist...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Separate abstracts were prepared for 60 papers in this volume of conference proceedings. None other papers in the proceedings were previously abstracted for EDB. Also included in the proceedings but not indexed separately are six workshop summaries and a session introduction. (LEW)

UK PubMed Central (United Kingdom)

Records of past climates contained in ice cores, ocean sediments, and other archives show that large, abrupt, widespread climate changes have occurred repeatedly in the past. These changes were especially...Full Text Available

UK PubMed Central (United Kingdom)

It is now widely accepted that novel infectious disease can be a leading cause of serious population decline and even outright extinction in some invertebrate and vertebrate groups (e.g., amphibians)....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

Science.gov (United States)

We present a new approach for growing Si nanowires directly from a silicon substrate, without the use of a metal catalyst, silicon vapor or CVD gasses. The growth can be performed in a furnace type configuration at moderate temperatures or in localized regions by resistive heating. Since the silicon wires grow directly from the silicon substrate, they do not need to be manipulated nor aligned for subsequent applications. Wires in the 20-50 nm diameter range with lengths over 80 ?m can be grown by this technique. We have studied the effects of various growth parameters, including temperature, substrate orientation, initial sample cleaning and carrier gasses. Results indicate that most important parameters in the growth of the nanowires are the surface cleaning, the temperature and the type of carrier gas used. A model is proposed, which involves an oxide catalyst for the process, with the growth of the ...

Energy Technology Data Exchange (ETDEWEB)

Human beings are confronted with another grievous disaster - coal fire. The monitoring on underground coal bed combustion relied on drilling supervising in the past, but this method is not good. By taking the coal fire of Gulaben mine in Inner Mongolia Autonomous Region as an example, the monitoring methods of underground coal bed combustion were explored based on the hyperspectra and high-resolution remote sensing technology. By employing the OMIS imaging apparatus developed by Shanghai Institute of Technical Physics of Chinese Academy of Sciences, the airborne hyperspectral images and the characteristic spectra of different types were obtained and the temperature was measured synchronously on the ground. Then according to the correlation of DN value of the thermal infrared band and surface temperature, the image information was processed, the spectral features were analyzed, and the surface ...

International Nuclear Information System (INIS)

In recent years, there has been increased emphasis on techniques to enhance two-phase flow heat transfer. The resulting increase in the use of heat transfer augmentation and the engineering importance of the subject presents this investigation in order to study the effect of different heater surface configurations on two-phase flow instabilities. The authors present the results of an experimental and theoretical study, summarized as: instabilities are not affected by small changes in heat transfer; nucleate boiling increases system unstability; amplitude of the oscillations increases as the axial temperature gradient over the heater increases; for the same type heater surfaces system stability increases with decreasing equivalent diameter; period of the oscillations depend on the heater surfaces; and linearized analysis and steady-state data can be used to determine the oscillation thresholds.

British Library Electronic Table of Contents (United Kingdom)

Irradiation of EP-823 (16Cr12MoWsiVNbB) ferritic-martensitic steel with 7-MeV Ni++ ions and with 30- and 70-keV He+ ions at a temperature of 500?C was followed by an increase in the microhardness, which was due to both radiation point defects and changes in the phase composition and the dislocation structure of the steel. It was found that the dependence of the largest relative increase in the microhardness on the concentration of radiation-induced point defects in the near-surface region of the steel under irradiation with different ions correlated with an analogous dependence of the surface segregation of silicon and chromium.

British Library Electronic Table of Contents (United Kingdom)

Although the outer surface of single-walled carbon nanotubes (atomically thin cylinders of carbon) can be involved in a wide range of chemical reactions, it is generally thought that the interior surface of nanotubes is unreactive. In this study, we show that in the presence of catalytically active atoms of rhenium inserted into nanotubes, the nanotube sidewall can be engaged in chemical reactions from the inside. Aberration-corrected high-resolution transmission electron microscopy operated at 80?keV allows visualization of the formation of nanometre-sized hollow protrusions on the nanotube sidewall at the atomic level in real time at ambient temperature. Our direct observations and theoretical modelling demonstrate that the nanoprotrusions are formed in three stages: (i) metal-assisted d...

British Library Electronic Table of Contents (United Kingdom)

The objective of materials research is the development of economical, safe and efficient synthesis routes that lead to the formation of a photocatalyst which is able to overcome performance problems related to particle size, crystallinity, or low surface area. Here, we report high-quality functional nanoparticles of calcium bismuth mixed oxide with 15nm nominal size corresponding to a specific surface area of 41m^2/g which were produced by single-step flame spray synthesis (FSS). The high temperature of the flame afforded creation of oxygen vacancies which were quantified by near edge X-ray absorption fine structure (NEXAFS) spectra. These two parameters, developed active surface area and created in the flame oxygen vacancies, allowed to enhance the photocatalytic activity of calcium bismu...

Energy Technology Data Exchange (ETDEWEB)

One third of the microstructure of glassy carbon (GC) consists of closed pores. Density measurements indicate that the total pore volume depends only on the heat treatment temperature and not on the heat treatment time, a characteristic of coarsening. The kinetics of coarsening of these pores on heat treatment has been investigated by analyzing the changes in specific surface area of the pores as determined by the small angle X-ray scattering (SAXS) technique. A part of the surface area change is due to thermal expansion induced microcracking. Both the superposition method after correcting the thermal expansion induced surface area change and the curve fitting method give an activation energy of 64 +/- 10 kcal/mole. This value is compared with the activation energies of various rate processes in graphite. A model of coarsening of the pores based on a vacancy migration mechanism is proposed.

Science.gov (United States)

This report is a compilation of the Chalk Point surface weather and ambient atmospheric profile data for the second intensive test period, June 14-24, 1976. The atmospheric profiles were made using rawinsonde instrumentation. The compilation includes the 0700 EST daily weather chart, hourly surface observations from Chalk Point, Patuxent River Naval Test Center, MD and Andrews Air Force Base, MD. Temperature, relative humidity, dew point, wind speed and wind direction are presented in graphical profiles. All other data are presented in tabular form.

Energy Technology Data Exchange (ETDEWEB)

Hard surface finishing represents the final manufacturing step for functional areas of machine elements in state-of-the-art production. Raceways of rolling bearing rings are ground and honed to the required low roughness. Plastic deformation is restricted to a narrow edge zone of the hardened steel. Reheating of the machined components below the martensite tempering or bainite transformation temperature results in a marked decrease of the XRD line width on the surface. The investigated samples are made of through-hardened standard bearing steel 100Cr6 (international denotation: SAE 52100). On the basis of a material model that explains the effect as a complex diffusion process of dislocational carbon segregation, i.e. static strain aging, the measured kinetics of the XRD line width reduction is simulated by an Arrhenius-type equation, which describes the rate-controlling reaction step of temper carbide dissolution. The ...

CERN Document Server

The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50 - 200 eV, whose nature is not yet well known. To explain the prominent absorption features in the soft X-ray spectra of the highly magnetized (B ~ 10^{14} G) X-ray dim isolated NSs (XDINSs), we theoretically investigate different NS local surface models, including naked condensed iron surfaces and partially ionized hydrogen model atmospheres, with semi-infinite and thin atmospheres above the condensed surface. We also developed a code for computing light curves and integral emergent spectra of magnetized neutron stars with various temperature and magnetic field distributions over the NS surface. We compare the general properties of the computed and observed light curves and integral spectra for XDINS RBS\\,1223 and conclude that the observations can be ...

Energy Technology Data Exchange (ETDEWEB)

Room-temperature phosphorescence (RTP) has generated considerable interest over the past several years. Several materials have been used to induce RTP from a variety of compounds. However, there is still a need to test additional materials and experimental conditions for RTP so the maximum sensitivity and selectivity can be obtained. In this work, three solid surfaces and several experimental conditions were tested for RTP of nitrogen heterocycles and aromatic amines. Nitrogen heterocycles and aromatic amines are an important class of compounds as shown by work in areas such as environmental research and coal liquefaction research. 18 references.

Science.gov (United States)

Intermetallic compounds are regarded as highly promising for applications as high temperature structural materials. However, recent studies have demonstrated that a number of ordered alloys exhibit environmental embrittlement when tested in various environments at ambient temperature. When exposed to hydrogen gas or electrolytically charged with hydrogen, a significant ductility loss has been reported. The reaction of water vapor with reactive elements in the crack tip results in the generation of atomic hydrogen which diffuses from the surface to the interior and causes embrittlement. In this paper, the authors try to analyze the sensitivity of hydrogen embrittlement of ordered alloys based upon energetical considerations.

Energy Technology Data Exchange (ETDEWEB)

This paper states the concept of a heat-resistant structure of the HOPE airframe having a 10 ton weight when lifting off and also the research situation of heat-resistant structural materials. To study the structure, established are design conditions for lift-off, reentry to the atmosphere and landing. As to the load condition, the load at the time of lift-off is most critical. Relating to the temperature environment condition, thermal analysis is made of the time when a HOPE is on the orbit (low-temperature range) and reenters the atmosphere (high-temperature range), when the temperature environment is critical. The analysis shows that the temrerature environment is in a {minus}80-1700{degree}C (range). The heat-resistant structural materials are developed so as to meet these conditions. The paper describes distribution of the airframe surface temperature by ...

Energy Technology Data Exchange (ETDEWEB)

The temperature elevations in anatomically based human phantoms of an adult and a 3-year-old child were calculated for radio-frequency whole-body exposure. Thermoregulation in children, however, has not yet been clarified. In the present study, we developed a computational thermal model of a child that is reasonable for simulating body-core temperature elevation. Comparison of measured and simulated temperatures revealed thermoregulation in children to be similar to that of adults. Based on this finding, we calculated the body-core temperature elevation in a 3-year-old child and an adult for plane-wave exposure at the basic restriction in the international guidelines. The body-core temperature elevation in the 3-year-old child phantom was 0.03 deg. C at a whole-body-averaged specific absorption rate of 0.08 W kg{sup -1}, which was 35% smaller than in the adult female. This ...

Energy Technology Data Exchange (ETDEWEB)

With an objective to learn mechanisms in low-rank coal reformation processes, change of properties on coal surface was discussed. Difficulty in handling low-rank coal is attributed to large intrinsic water content. Since it contains highly volatile components, it has a danger of spontaneous ignition. The hot water drying (HWD) method was used for reformation. Coal which has been dry-pulverized to a grain size of 1 mm or smaller was mixed with water to make slurry, heated in an autoclave, cooled, filtered, and dried in vacuum. The HWD applied to Loy Yang and Yallourn coals resulted in rapid rise in pressure starting from about 250{degree}C. Water content (ANA value) absorbed into the coal has decreased largely, with the surface made hydrophobic effectively due to high temperature and pressure. Hydroxyl group and carbonyl group contents in the coal have decreased largely with rising reformation treatment ...

British Library Electronic Table of Contents (United Kingdom)

A solvent extraction method was developed to obtain methanolic extracts rich in antioxidants from banana peel. Central composite design ''2^3+star'' and response surface methodology were used in order to optimise the number of extraction steps, extraction temperature and extraction time. The number of extractions was statistically the most significant factor in scavenging activity against both DPPH? and ABTS?^+ radicals and in the inhibition of TBARS formation, while the extraction temperature had an important impact on the capacity to prevent b-carotene bleaching. However, the effect of the extraction time on antioxidant activity was less important. The optimum values of the factors that influence the capacity to scavenge DPPH? and ABTS?^+ radicals or to inhibit b-carotene bleaching were ...

Energy Technology Data Exchange (ETDEWEB)

The scope of the present article is two-fold. Firstly, to conduct an experiment to provide the temperature-time history of the cooling of a hot ball bearing in quiescent ambient air. Secondly, to predict the temporal variation of the bearing under the hypothesis of natural convection, radiation or natural convection coexists with radiation for a non-vanishing total hemispherical emissivity of the surface of the bearing. Numerical solutions of the three governing nonlinear lumped heat equations were carried out with a Runge-Kutta-Fehlberg (RKF45) algorithm accounting for automatic step size control. The experimental data was obtained with chrome steel ball bearings of diameter 0.953 cm (7/16 in) heated in an electric oven to a pre-set temperature. The heated bearing was exposed later to ambient air at atmospheric temperature and pressure. (orig.)

Energy Technology Data Exchange (ETDEWEB)

We report the lasing characteristics of gain-guided AlGaInP/AlGaAs visible vertical-cavity surface-emitting laser diodes. At room temperature, continuous-wave operation is achieved over the wavelength range of 657--685 nm with the minimum threshold current at 670 nm. Devices with a 10-[mu]m diameter have threshold currents as low as 1.25 mA at room temperature (297 K) and 0.8 mA at 250 K. In addition, a single predetermined linear polarization state is found, independent of the lasing mode order and operating temperature.

Energy Technology Data Exchange (ETDEWEB)

The present invention concerns a high thermal load heat receiving plate such as a divertor plate of a thermonuclear device. The high thermal load heat receiving plate of the present invention has a cooling performance capable of suppressing the temperature of an armour tile to less than a threshold value of the material against high thermal loads applied from plasmas. Spiral polygonal pipes are inserted in cooling pipes at a portion receiving high thermal loads in the high temperature load heat receiving plate of the present invention. Both ends of the polygonal pipes are sealed by lids. An area of the flow channel in the cooling pipes is thus reduced. Heat conductivity on the cooling surface of the cooling pipes is increased in the high thermal load heat receiving plate having such a structure. Accordingly, temperature elevation of the armour tile can be suppressed. (I.S.).

International Nuclear Information System (INIS)

Austenitic stainless steel AISI 304 has been nitrided by radio frequency (rf) plasma containing various nitrogen-hydrogen gas mixtures, in order to study the effect of hydrogen on structure and magnetic properties of the formed compound layer. The thermal temperature has been measured at the vicinity of the samples. The compound layer thus produced has been characterized using, X-ray diffractometer and vibration sample magnetometer. Providing the total pressure of nitrogen and hydrogen is held constant, the addition of hydrogen up to 50% gives new structural phases. The magnetization values of the plasma treated samples are strongly dependent on the percentage of H_2 in the gas phase. An excessive amount of hydrogen (#approx#75%) on the other hand, retards the nitriding process. The surface temperature of the sample and plasma condition is crucial factors for nitriding process.

Science.gov (United States)

Symplectic integrators designed for simulating soft matter at constant temperature and constant pressure (or constant surface tension) are presented. In addition to the well-known merits of symplectic integrators, such as long time stability, these methods allow the estimation of thermal heat production/absorption and thus entropy differences through a simple function of the time scaling factor ?. The relative entropy estimation around crystal-liquid phase transition is given for systems with soft core repulsive potential.

International Nuclear Information System (INIS)

The utilization of electrically heated rods for the simulation of nuclear fuel rods represents an universally adopted method by the nuclear industry to study thermalhydraulic problems. The present work represents the development of a method to obtain the time variation of the electric linear power necessary to simulate a given nuclear power transient in order to yield the same temperature and heat flux conditions in the surface of the electrical heater that would be obtained by the nuclear fuel rod. (Author).

International Nuclear Information System (INIS)

Zr-Al metallo-organic compounds were thermally decomposed to prepare ZrO_2-Al_2O_3 composite powders. The specific surface area was dependent on the organofunctional groups of the starting organic compounds. The pore size distribution was dependent on the heating rate when the heating temperature was the same. 4 refs.; 4 figs.

International Nuclear Information System (INIS)

An apparatus allowing the photoexcitation of barium atomic beam over its whole surface is described. This photoexcitation is achieved by another barium spectrum emitted up steam of the beam by a cathodic out-flow produced at the exit oven. The fluorescence spectrum is studied in detail as well as the influence of different parameters, such as oven temperature, current intensity of the outflow, and excitation depth. A calculation shows how to determine Einstein coefficient, oscillator strengths and atomic lifetimes from our experimental measurements.

Energy Technology Data Exchange (ETDEWEB)

It is shown that observations of the lithium isotope ratio in high surface temperature Population II stars may be critical to cosmological nucleosynthesis models. In particular, decaying particle scenarios as derived in some supersymmetric models may stand or fall with such observations. 18 references.

British Library Electronic Table of Contents (United Kingdom)

Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433?479 K were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined. It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine.

International Nuclear Information System (INIS)

The recently observed phenomenon of boron uphill diffusion during low-temperature annealing of ultrashallow ion-implanted junctions in silicon has been investigated. It is shown that the effect is enhanced by preamorphization, and that an increase in the depth of the preamorphized layer reduces uphill diffusion in the high-concentration portion of boron profile, while increasing transient enhanced diffusion in the tail. The data demonstrate that the magnitude of the uphill diffusion effect is determined by the proximity of boron and implant damage to the silicon surface.

Energy Technology Data Exchange (ETDEWEB)

Neutron reflectometry (NR) was used to measure the concentration profile of a symmetric PEP/dPEP polymer blend with nanometer-scale resolution in the one-phase region. The shape of the profile near the surface was found to differ significantly from mean-field theory predictions for all bulk concentrations and temperatures surveyed. The profile shape is flattened at the surface over a distance about half the bulk correlation length, a length scale far greater than that of the dispersive forces that are the dominant microscopic interaction in such blends. We introduce a new method for extracting the surface energy difference that drives segregation based on the Gibbs adsorption equation (GAE) and compare it to a previous method based on mean-field theory. While both methods produce qualitatively similar results (the surface energy of pure dPEP is {approx}0.21 mJ/m{sup 2} smaller than ...

Energy Technology Data Exchange (ETDEWEB)

The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1{times}10{sup 14} cm{sup {minus}2} Si{sup +} was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050{degree}C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si{sup +} ion range is observed at all temperatures, extrapolating to {approximately}1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of {lt}10 nm. The data presented here demonstrate that in the range of annealing ...

International Nuclear Information System (INIS)

The nature of the electrolyte strongly influences the electrode kinetics of the oxygen evolution reaction (OER) and electrochemical ozone production (EOP) mainly by affecting the degree of coverage by the intermediates of both processes. The anomalous behaviour of the Tafel coefficient, b, as a function of temperature was attributed to surface adsorption of the electrolyte species, and the competition between them, as well as gas bubble adherence. Comparison of the current efficiencies of the EOP, PHI_E_O_P, determined for different temperatures and supporting electrolyte compositions, showed the presence of fluorinated anions increases PHI_E_O_P. The influence of the anion nature on PHI_E_O_P, when analysed in the light of the proposed electrode mechanism, reveals introduction into the electrolyte of anions having a high electronegativity changes the double layer structure resulting in an increase of ...

International Nuclear Information System (INIS)

FT-IR spectra of the products obtained in each step of the tetramethyltin (TMT)/3-wt.% Re_2O_7/Al_2O_3-SiO_2 and TMT/Al_2O_3-SiO_2 system preparation are presented and discussed. The obtained spectra show that TMT reacts with alumina-silica hydroxyl groups already at room temperature, yielding surface methyltin compounds; NH_4ReO_4 reacts with alumina-silica surface at temperatures up to 423 K, yielding rhenium surface species and ammonia, which is strongly bonded by acidic sites of the Broensted kind. FT-IR spectrum of the system (TMT)/3-wt.% Re_2O_7/Al_2O_3-SiO_2 indicated the absence of surface methyl tin compounds observed on the surface system TMT/Al_2O_3-SiO_2 , and the presence of physically adsorbed TMT; after 5 h of evacuation of the TMT/3-wt.% Re_2O_7/Al_2O_3-SiO_2 system, the FT-IR spectrum indicated the presence of only a single ...

Science.gov (United States)

Understanding climate development in the central Andes is important in determining the relationship between mountain range uplift and climate change. Recent work along the western margin of the central Andes has led to the development of two competing hypotheses: 1) that climate change is directly responsible for uplift or 2) that uplift controls climate change. In the first scenario, uplift results from increased friction at the plate boundary due to sediment-starvation of the trench which is a function of decreased run-off (particularly post 14 Ma) due to global cooling. In the second scenario progressive uplift of the Andean Cordillera during the Miocene resulted in a strong orographic effect with a concomitant rainshadow west of the Andes. To determine the relationship between climate change and uplift it is necessary to ascertain precisely, when the climate changed, the nature of that change and when uplift occurred. With respect to climate change a key question that has been ...

Energy Technology Data Exchange (ETDEWEB)

Diel vertial migrations of the marine dinoflagellates Gonyaulax polyedra Stein and Ceratium furca (Ehr.) Clap. et Lachm, were followed in a laboratory tube (2.02 m x 0.25 m) under a 12:12h light:dark cycle. The effects of temperature stratification, two levels of surface irradiance and nitrogen depletion on patterns of vertical migrations were examined. At temperatures between 22 to 26/sup 0/C with small temperature gradients, both species migrated at a rate of 0.7 to 1.0 mh/sup -1/. Steeper thermoclines (ca. 0.8/sup 0/C 0.1 m/sup -1/) with temperatures below ca. 20/sup 0/C caused a marked decrease in swimming speed which resulted in accumulations of cells in these thermocline regions. Under conditions of nutrient sufficiency both algae migrated into the surface layers at irradiance values of over 1000 ..mu..E m/sup -2/s/sup -1/. Increasing nitrogen depletion ...

Energy Technology Data Exchange (ETDEWEB)

Engineering materials for use in low heat rejection engines are required to function under stringent tribological conditions. Severe wear damage and high friction between the components of the tribosystem limit the number of potential materials suitable for such application conditions. The superalloys X-750 and 188 are composed of alloying elements that not only promote a high mechanical and chemical stability but may also result in a reduced wear rate and friction coefficient at elevated temperatures. As a part of the DOE-ECUT Tribology program at Argonne, the present study was undertaken to evaluate the tribological characteristics of these alloys that will also be utilized as the substrates for ion beam deposited lubricous coatings. A wear test rig that crudely simulated the sliding conditions between a piston ring and a cylinder liner in an operating engine was utilized for friction and wear studies. The test results indicated that the wear and friction ...

Energy Technology Data Exchange (ETDEWEB)

Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm was queried at different spatial scales, and the spatial relationship between primary ...

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the optimisation of solar-heated cavity receivers in which solar energy collected by a paraboloid collector is converted into electrical energy. The focussed solar energy enters the receiver through an aperture to heat the working fluid, which flows inside the receiver tubes and is compressed by the compressor of a gas turbine system, to the highest process temperature. A method of calculating the distribution on the inner receiver surfaces of the solar radiation reflected by the paraboloid collector is presented to begin with. The interchange of radiant energy inside the receiver cavity can be calculated on this basis, including the radiation loads, the temperatures of the inner receiver walls, and the radiative and convective losses. The temperature fields in the tube walls must be known for determining the strength required of receiver tubes; they can be derived from the ...