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This study investigates the turnover of polysaccharides by heterotrophic bacterioplankton in the northern Bay of Biscay, a productive marine system on the continental margin of the temperate Atlantic Ocean. Bacterial biomass production (BBP) near the surface ranged from 0.5 to 25.7 nmol C L?1 h?1 during small phytoplankton blooms in May and June that occurred after the main spring bloom. A direct relationship between BBP and total polysaccharides strongly suggests the dependence of bacterial growth on the availability of semi-labile organic matter. Concentrations of combined glucose as well as rate constants of extracellular glucosidase activity and glucose uptake were determined to estimate the actual carbon fluxes from bacterial polysaccharide turnover. Results reveal that ...

KoreaScience (Korea)

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Wastenet

... Studies People Projects Opportunities Framework Critical Sectors Development Goals Geographic Region Geographic Scale Research Themes Printer-Friendly Center for Ocean Solutions Early Career Fellowship Program Location: Stanford, California Source: The Center for Ocean Solutions (“Ocean Solutions”) seeks one or more recent graduates who have received a JD, MBA or PhD in the natural, physical or social sciences in the last five years, and who ...

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 is more than 1 meter ...

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 ...

Wastenet

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

British Library Electronic Table of Contents (United Kingdom)

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

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The 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 ...

CERN Document Server

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

Science.gov (United States)

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.

CERN Document Server

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

Science.gov (United States)

Metabolic carbon labelling experiments enable a large amount of extracellular fluxes and intracellular carbon isotope enrichments to be measured. Since the relation between the measured quantities and the unknown intracellular metabolic fluxes is given by bilinear balance equations, flux determination from this data set requires the numerical solution of a nonlinear inverse problem. To this end, a general algorithm for flux estimation from metabolic carbon labelling experiments based on the least squares approach is developed in this contribution and complemented by appropriate tools for statistical analysis. The linearization technique usually applied for the computation of nonlinear confidence regions is shown to be inappropriate in the case of large exchange fluxes. For this reason a sophisticated compactification transformation technique for nonlinear statistical analysis is ...

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This paper deals with electron flux densities and electron energy flux densities in positive column discharges. Recent kinetic calculations by Uhrlandt and Winkler have revealed the interesting physical phenomenon of radially inward directed energy flux densities in positive column plasmas. We have used a self-consistent positive column model, based on an accurate and highly detailed Monte Carlo code, to study this effect in more depth. The results of this study show a rather complex physical picture of electron particle and energy flux densities. Electrons with low energies usually exhibit radially outward directed particle and energy flux densities. At energies above the threshold for electronic excitation particle and energy flux densities are usually inward directed. Only close to the wall, at total energies above ...

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SZI global distribution due to biogeochemical cycle in environment reservoirs has been studied. It is shown that during the operation of nuclear fuel cycle facilities and at a modern level of the decontamination factor the SZI concentration in some natural media (soil, the Earth biosphere, ocean mixing layer) will increase by 4-5 orders. Recommended gradual increase of the decontamnation factor in time for conserving the SZI concentration level not exceeding one order in comparison with modern one is given. At that to the end of the century the decontamination factor must be of an order of 1 x 10U in the case of SZI intake to the ocean mixing layer and of 1 x 10V in the case of its intake to the atmosphere.

British Library Electronic Table of Contents (United Kingdom)

Remotely sensed ocean color data and numerical modeling have been used to study the phenology of both spring and fall phytoplankton blooms (FPBs) in the Nova Scotian Shelf (NSS)-Gulf of Maine (GoM) region. The ocean color data reveal a general pattern of westward progression of the spring phytoplankton bloom (SPB), and an eastward progression of the FPB in the NSS-GoM region. The spatial pattern of mean chlorophyll concentration in spring is similar to that in fall, with a lower concentration in the NSS and higher in the GoM. Interannually, there is a weak but significant tendency for years with earlier (delayed) SPBs to be followed by delayed (earlier) FPBs, but the mean chlorophyll concentrations during SPBs are not correlated with those during FPBs. The interannual variability of SPB ti...

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The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an ...

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The Subseabed Disposal Project (SDP) was part of an international program that investigated the feasibility of high-level radioactive waste disposal in the deep ocean sediments. This report briefly describes the seven-step iterative performance assessment procedures used in this study and presents representative results of the last iteration. The results of the performance are compared to interim standards developed for the SDP, to other conceptual repositories, and to related metrics. The attributes, limitations, uncertainties, and remaining tasks in the SDP feasibility phase are discussed.

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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.

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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.

CERN Document Server

The relationship between the emission line equivalent width and the continuum luminosity, so called the Baldwin effect, plays an important role in studying the broad line region physics of AGNs. Using the archived ultraviolet spectra obtained by IUE, HST and HUT in 1978-2002, we investigated the intrinsic CIV Baldwin effect of a best-studied Seyfert 1 galaxy NGC 4151. Both its continuum flux and CIV emission line flux varied about two orders of magnitude in more than two decades, making it one of the best targets for studying the slope variation of the Baldwin effect. We fitted the CIV line profile of the 490 archived UV spectra of NGC 4151 with a same model consisting of a few Gaussian components, and derived the slope in the log-log plot for the total flux of CIV emission line against the UV continuum flux in different observation ...

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In 1982 the semi-submersible drilling unit Ocean Ranger capsized and sank off the Grand Banks, resulting in the loss of the entire 84-man crew. A Royal Commission was set up to conduct an enquiry into the incident, and to carry out a process of research and opinion-gathering towards providing recommendations to both federal and Newfoundland governments. The primary purpose of the Commission was to determine why the Ocean Ranger sank, why none of the crew were saved, and how to avoid similar disasters. A number of studies and seminars were held to focus expert knowledge and opinion in several key fields and to update studies and fill gaps in the data base. Summaries of selected study reports and the seminar proceedings are presented in the following areas: the environment, including ice, marine climatology, weather forecasting services, wave climatology, oceanographic information, ...

International Nuclear Information System (INIS)

A numerical study of a natural convection in a rectangular cavity with the low-Reynolds-number differential stress and flux model is presented. The primary emphasis of the study is placed on the investigation of the accuracy and numerical stability of the low-Reynolds-number differential stress and flux model for a natural convection problem. The turbulence model considered in the study is that developed by Peeters and Henkes (1992) and further refined by Dol and Hanjalic (2001), and this model is applied to the prediction of a natural convection in a rectangular cavity together with the two-layer model, the shear stress transport model and the time-scale bound #upsilon#"2-f model, all with an algebraic heat flux model. The computed results are compared with the experimental data commonly used for the validation of the turbulence models. It is shown that the ...

International Nuclear Information System (INIS)

The report presents the results of experimental studies conducted to provide a description of the conditions which lead to the occurrence of critical heat flux (CHF), in Combustion Engineering (C-E) fuel assemblies using the C-E standard spacer grid. A CHF correlation is presented which is based on CHF data obtained in tests with electrically heated rod bundles representative of the C-E 14 x 14 and 16 x 16 array fuel assemblies. The results reported are for a uniform axial heat flux distribution. The experiments were conducted in the Medium Pressure Heat Transfer Flow Loop at the Chemical Engineering Research Laboratories at Columbia University.

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, ...

KoreaScience (Korea)

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KoreaScience (Korea)

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

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This study assesses the feasibility of removing the FFTF reactor vessel from its current location in the reactor cavity inside the Containment vessel to a transporter for relocation to a burial pit in the 200 Area.

International Nuclear Information System (INIS)

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 waste which contains traces of natural radioactive materials. The initial planning has focused on the Middlesex, New Jersey, Sampling Plant site and surrounding properties, which contain on the order of 100,000 metric tons of material. The Belgian Congo uranium ore and other uranium ores used by the United States were handled at the sampling plant site and have since been removed.

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations are being conducted on a single-cylinder direct-injection diesel engine to examine the transient heat transfer characteristics. Transient temperature data from stationary locations in the piston and cylinder head were used as the basis for determining the transient heat flux rates. Transient surface temperature was measured using the thin film thermocouples. At first, the transient heat flux rates calculated from the analysis method used in this paper were compared with the results from FEM. The results showed good agreement. Using this analysis method, the transient heat flux rates were calculated. The tests were performed at 1200 rpm with constant air flow. The parameters that were varied included the fuel rate and injection timing. Based on these results, the present paper discusses the mechanism of heat rejection in a direct-injection diesel engine. 8 refs., 16 figs.

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 ...

International Nuclear Information System (INIS)

Swelling hemoglobin CC erythrocytes stimulates a ouabain-insensitive K flux that restores original cell volume. Studies were performed with the K analog, "8"6Rb. This volume regulatory pathway was characterized for its anion dependence, sensitivity to loop diuretics, and requirement for Na. The swelling-induced K flux was eliminated if intracellular chloride was replaced by nitrate and both swelling-activated K influx and efflux were partially inhibited by 1 mM furosemide or bumetanide. K influx in swollen hemoglobin CC cells was not diminished when Na in the incubation medium was replaced with choline, indicating Na independence of the swelling-induced flux. Identical experiments with hemoglobin AA cells also demonstrated a swelling-induced increase in K flux, but the magnitude and duration of this increase were considerably less than that seen with hemoglobin CC cells. The ...

British Library Electronic Table of Contents (United Kingdom)

Even if there have been efforts to validate remote-sensing-based energy balance models, which provide evapotranspiration (ET) maps over a large spatial scale, few studies have been conducted to validate their performance in Korea. In this study, surface energy balance fluxes including ET were estimated and inter-compared with two different models using the Landsat-5 Thematic Mapper (TM) image over a watershed scale in Korea. While there were larger spatial discrepancies for net radiation, soil heat and sensible heat fluxes on a pixel-by-pixel basis between the two models, relatively smaller spatial discrepancies for the latent heat flux and daily ET were detected. The spatial discrepancies for the daily ET were larger in low topography and dense vegetation ranges. Despite the different par...

International Nuclear Information System (INIS)

Large sized reactor such as 540 MWe Pressurised Heavy Water Reactor (PHWR) requires continuous in core monitoring of local flux in order to provide effective control and protection. About 198 self powered neutron detectors (SPNDs) of the straight individually replaceable type are distributed in the reactor core. For purposes of reactor regulation, 42 prompt responding cobalt SPNDs called zone control detectors (ZCDs) are housed in vertical flux units (VFUs) and these are uniformly distributed in 14 power zones. The in core detectors used for spatial control by ZCCs do not accurately represent average zone power as they sense the flux over a small volume. Flux mapping system (FMS) comprising of 102 vanadium SPNDs in 26 VFUs, provide accurate measure of neutron flux, even though they have slow response to change in neutron flux levels. For reactor protection ...

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.

Energy Technology Data Exchange (ETDEWEB)

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.

Energy Technology Data Exchange (ETDEWEB)

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

CERN Document Server

We study the phonon fluxes emitted when the condensate velocity crosses the speed of sound, i.e., in backgrounds which are analogue to that of a black hole. We focus on elongated one dimensional condensates, and on stationary flows. Our theoretical analysis and numerical results are based on the Bogoliubov-de-Gennes equation without any further approximation. The spectral properties of the fluxes and of the long distance density-density correlations are obtained, with and without an initial temperature. In realistic conditions, we show that the condensate temperature dominates the fluxes, and thus hides the presence of the spontaneous emission (the Hawking effect). We also explain why the temperature amplifies the long distance correlations which are intrinsic to this effect. This confirms that the correlations pattern offers a neat signature of the Hawking effect. Optimal conditions to observe the ...

Science.gov (United States)

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

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Two important greenhouse gases, CO{sub 2} and CH{sub 4}, are closely connected to the carbon cycling of wetlands. Although virgin wetlands are mostly carbon accumulating ecosystems, major proportion of the CO{sub 2} bound annually in photosynthesis is released back to the atmosphere. Main portion of the carbon cycling in wetlands is quite fast while a small proportion of carbon diffusing from soil is released from organic matter, which may be ten thousand years old. Methane is formed in the anaerobic layers of wetlands, from where it is released gradually to the atmosphere. The decomposition in anaerobic conditions is very slow, which means that usually only a few percent of the annual carbon cycling takes place as methane. Research on CO{sub 2} fluxes of different virgin and managed peatlands was the main topic of this project during the first phase of SILMU. The measurements were made during two seasons in varying conditions in c. 30 study ...

Energy Technology Data Exchange (ETDEWEB)

Reactive sticking coefficients (RSCs) were measured for silane and disilane on polycrystalline silicon for a wide range of temperature and flux (pressure) conditions. The data were obtained from deposition-rate measurements using molecular beam scattering and a very low-pressure cold-wall reactor. The RSCs have nonlinear Arrhenius temperature dependencies and decrease with increasing flux at low (710 /sup 0/C) temperatures. Several simple models are proposed to explain these observations. The results are compared with previous studies of the SiH/sub 4//Si(s) reaction and low-pressure chemical vapor deposition-rate measurements.

International Nuclear Information System (INIS)

This article discusses the Daya Bay nuclear power plant in-core flux thimble tube in-service inspection method and strategy. High light of the multiple frequency eddy current technology adopted including frequency and probe choice, standard design, data acquisition process are involved. The wear defect-growing trends are studied on base of the history data, which contribute to the in-service inspection strategy decision. (authors)

CERN Document Server

Solar wind effect on the muon flux at sea level

British Library Electronic Table of Contents (United Kingdom)

Maldives comprise some of the most characteristic and significant atoll systems, but the meiobenthic assemblages of these islands are still largely unknown. A study on meiofauna was conducted on three Maldivian sandy back-reef platforms differently exposed to stronger westerly monsoons. Clear high energy effects of the waves causing currents and erosions were observed at the completely exposed and isolated offshore reef of Thoddoo Island. Wave energy of medium intensity was confirmed at Rasdhoo by depositional structures (finolhu), while a medium to low energy level was recorded at Gulhi on the basis of the presence of a low sandy bar. The meiofaunal assemblage counted 17 major taxa. Copepods and nematodes were dominant, followed by platyhelminthes and polychaetes. The nematode assemblage ...

British Library Electronic Table of Contents (United Kingdom)

The Taiwan Strait is an important channel in the west Pacific Ocean transporting water and chemical constituents between the East China Sea and the South China Sea. Due to its complex bottom topography, alternating monsoon forcing and conjunction of several current systems [such as the Zhejiang-Fujian (Zhe-Min) Coastal Current, the Kuroshio intrusion and the extension of the South China Sea Warm Current], the physical and biogeochemical processes and ecosystem dynamics in the Taiwan Strait vary significantly both in space and in time. Our recent interdisciplinary studies, combining in situ and remote sensing observations with numerical modeling, allow us to address several important issues concerning the Taiwan Strait. The temporal and spatial variation of circulation in the Taiwan Strait ...

Energy Technology Data Exchange (ETDEWEB)

An experimental study of the {sup 241}Am incineration in a high-intensity thermal neutron flux was carried out at the high-flux reactor of the Institut Laue-Langevin in Grenoble. The combination of nuclear {gamma}-ray spectroscopy and off-line mass spectrometry methods made possible the measurement of several parameters of the transmutation chain and the first experimental determination of the unknown {sup 242gs}Am thermal neutron capture cross section, which plays an essential role in the {sup 241}Am incineration process. During a 19 days irradiation in a thermal neutron flux of 5.6x10{sup 14} n/(s cm{sup 2}), (46{+-}5)% of the initial {sup 241}Am was transmuted by neutron capture of which (22{+-}8)% was incinerated by nuclear fission. A value of the thermal neutron cross section of {sup 242gs}Am(n,{gamma}) of (330{+-}50) barns was obtained. We show that this keeps the option open to incinerate {sup ...

Energy Technology Data Exchange (ETDEWEB)

In this article, the isotope geochemical study for Iceland is reviewed. Iceland is geologically unique because it is a subaerial exposure of Mid-Atlantic Ridge, which is caused by the interaction between the ridge and the Icelandic hot spot. To investigate what is happening beneath Iceland, many geochemical studies have been done. The geochemical studies using conventional Sr, Nd, Pb, He and O isotope tracers revealed the heterogeneity not only of the oceanic mantle, but also of the Icelandic hot spot mantle itself. Furthermore, the oxygen isotope studies revealed the reworking of the Icelandic crust which is altered by meteoritic water. The characterization of the Icelandic hot spot from the isotope geochemistry is very important in testing the hypothesis of the mantle-crust recycling. In near future, new tracers such as Li, B or Ce will be applied to this problem, and new ...

International Nuclear Information System (INIS)

Studies at Commissariat a l'Energie Atomique (CEA) have been under way for three years in an attempt to find methods for preventing and stopping denting. Tests have been performed in 28 model boilers (Ajax with U tubes and Clarinette with straight tubes). In these boilers, with continous injection and blowdown, and heat flux is about 40 W X cm"-"2 (126900 Btu/ft"2 X h). The kinetics of denting has been studied with different levels of faulting. Some high-temperature electrochemical measurements established the mechanism of denting in the boiler tests. Denting kinetics can be rationalized in terms of three main parameters: faulting level, heat flux, and relative mechanical strength of the tube compared to the support plate.

International Nuclear Information System (INIS)

The importance of point defects in semiconductor and function materials has been studied in detail, but effective means for detecting point defects has not been available for a long time. The end of range defects in Si, produced by 140 keV Ge"+ implantation, were investigated as detectors for measuring the interstitial concentration created by 42 keV B"+ implantation. The concentration of interstitial resulting from the B"+ implantation and the behavior of the interstitial flux under different annealing condition were given. The enhanced diffusion in the boron doped EPI marker, resulting from mobile non-equilibrium interstitials was demonstrated to be transient. Interstitial fluxes arising from processing can be detected by transient enhanced diffusion (TED) of doped marker layers as well

International Nuclear Information System (INIS)

The Cycle 8A static tests conducted in the Fast Flux Test Facility (FFTF) during 1986 have resulted in the separation of various feedback reactivity components. These feedback components, described by closed-form equations depending only on the reactor temperature field, can be regarded as database for the validation and/or calibration of feedback mechanistic models. The SASSYS safety analysis code contains the most developed feedback reactivity models and was selected for the comparison study between database and mechanistic calculations for the FFTF. Although detailed feedback models for control rod repositioning and core radial expansion/bowing exist, only the simple models were available in SASSYS at the time of this study. The results are described in this paper.

British Library Electronic Table of Contents (United Kingdom)

In this study, we thoroughly analyzed abrupt behaviors, trends, and periodicity properties of water vapor flux and moisture budget entering and exiting the four edges of the Pearl River basin based on the NCAR/NCEP reanalysis dataset by using the continuous wavelet transform and the simple two-phase linear regression technique. Possible implications for hydrological cycle and water resource management of these changes are also discussed. The results indicate that: (1) the water vapor propagating through the four edges of the Pearl River basin is decreasing, and it is particularly true for the changes of the water vapor flux exiting from the north edge of the study river basin. The transition point from increase to decrease occurs in the early 1960s; (2) The wavelet transform spectra indica...

Energy Technology Data Exchange (ETDEWEB)

The study was directed towards determining the usability of clay and fine wastes (CW and FW) of boron from the concentrator plant in Kirka (Turkey) as a fluxing agent in production of red mud (RM) brick. Both laboratory studies on the characterization of materials and industrial-scale tests for production of bricks were carried out. CW and FW, which have similar chemical composition but include different types and amounts of oxides, were added in amounts of 5, 10 and 15wt% to RM, which consists of high amounts of Fe{sub 2}O{sub 3}, Al{sub 2}O{sub 3}, SiO{sub 2} and alkalies. Six different sets of samples have been produced and fired at 700, 800 and 900{sup o}C. Dry shrinkage of green body, bending and compressive strength, firing shrinkage, water absorption, frost resistance and harmful magnesia and lime tests on heat-treated bodies have been performed. The mineralogical and mechanical tests showed that usability of boron ...

International Nuclear Information System (INIS)

In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at CEA/DSM with objectives to determine optimal conditions for transmutation and incineration of minor actinides (MA) in high intensity neutron fluxes. Our experimental tools based on alpha- and gamma-spectroscopy of the samples and the development of micro fission chambers could gather either microscopic information on nuclear reactions (total or partial cross sections for neutron capture and/or fission reactions) or macroscopic information on transmutation and incineration potentials. Neutron capture cross sections of selected actinides ("2"4"1Am, "2"4"2Am, "2"4"2Pu, "2"3"7Np) have already been measured at ILL, showing some discrepancies when compared to evaluated data libraries but in overall good agreement with recent data. The studies and possibilities offer by the MEGAPIE project to assess neutronic performances of a 1 MW ...

Energy Technology Data Exchange (ETDEWEB)

Compact heat exchangers have traditionally found wide application in the transportation industry, where they are used as evaporators and condensers in vapor compression cycles for air conditioning and refrigeration. Such heat exchangers possess numerous attractive features including high thermal effectiveness, small size, low weight, design flexibility, and pure counterflow, and they can accommodate multiple streams. Today, there is a widespread interest in expanding the range of application of compact heat exchangers to include phase-change heat transfer in the process industries, among others. An overall objective of this effort is to provide the basis for establishing design technology in this area. In the present study, small channel flow boiling heat transfer was extended to a rectangular channel (4.06 {times} 1.70 mm) using refrigerant 12 (R-12). As with the circular tube studies, the flow channel wall was electrically heated providing a ...

International Nuclear Information System (INIS)

An experimental study was carried out to determine the effect of rod-bowing on critical heat flux, using an electrically heated rod cluster. In this experiment, rod-bow was set to occur in the severest subchannel and axially at the middle between the last two spacers, with uniform axial heat flux. The maximum gap between the outer and inner rods was reduced variously to 1.6 mm, 1.00 mm and zero from the nominal value of 2.1 mm. Other experimental conditions were as follows: pressure 7 MPa; mass velocity 640-2600 kg/m"2sec; inlet subcooling 40-560 kJ/kg. Experimental results show only a slight rod-bowing effect, if any, compared with normal spacing, as confirmed by analysis of three-dimensional heat conduction around the rod-bowing area and by the local steam quality deviations calculated by subchannel analyses. (Auth.).

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...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

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)

Environmental Research Database

Objectives(i) Investigate the correlation between Antarctic sea-ice and equatorial sea-surface temperature anomalies in a realistically forced ocean model simulation of the last 50 years. (ii) Determine whether and how the enormous seasonal change in distribution of sea-ice modifies the seasonal cycle at the Equator. (iii) Determine the detailed pathways of wave propagation both in a historically-forced simulation and in response to realistic perturbations. (iv) Quantify the amplitude of the response i [continued...]DescriptionIt is well known that the equatorial ocean-atmosphere system plays a key role in global climate events such as the El Nino-Southern Oscillation (ENSO) phenomenon. There is now compelling evidence that changes in the Antarctic can strongly and quickly affect the equatorial ocean and the ENSO cycle. Observations demonstrate statistically significant correlations (teleconnections) between the Antarctic ...

Science.gov (United States)

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

Energy Technology Data Exchange (ETDEWEB)

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

Science.gov (United States)

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

Science.gov (United States)

... Distribution Unlimited: Approved for "i3a. ... 'he tide changes were obtained using the standard NOAA National Ocean Survey tide tables. ...

Energy Technology Data Exchange (ETDEWEB)

Cheap air conditioning from oceanic temperature differences is a possible new competitor for coal in coastal regions. Coal suppliers planning expansion in growing economies need to be aware of the possibilities and limitations of this new competitor. Ocean thermal energy conversion (OTEC) used to be uneconomic but the National Energy Laboratory of Hawaii (NELH) has developed a very economic method of utilising the temperature difference between warm ocean surface and cold deep ocean to generate energy for air conditioning. The article outlines the process and mentions demonstrations of OTEC technology to produce electricity and air conditioning at a site in Kailua-Kona, Hawaii. Indonesia and India have viable sites for OTEC installations, and NELH is working with Madras State on a project to construct a commercial OTEC plant in India. 2 photos.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The authors will be conducting an integrated seismic experiment to image the structure of the crust and upper mantle of northern California immediately before and after passage of the Mendocino Triple Junction. The purpose of this representation is to describe the project to other scientists interested in geological and geophysical processes in this region and to solicit input relevant to detailed siting of the funded seismic profiles. The experiment encompasses two field seasons: onshore seismic refraction/wide angle reflection data acquisition along three long profiles scheduled for late summer, 1993; and MCS deep crustal seismic reflection data acquisition accompanied by simultaneous large aperture recording using both ocean bottom and onshore seismographs, tentatively scheduled for summer, 1994. This study represents a component of a long-term, multi-disciplinary effort on the part of many investigators to exploit this well defined system ...

International Nuclear Information System (INIS)

Fusion energy has been studied in many countries such as U.S., France, Japan, Korea etc. Because it would provide much more energy for a given weight of fuel than any technology currently in use, and the fuel itself (primarily deuterium) exists abundantly in the Earth's ocean. Nuclear fusion reactor uses tritium and deuterium as fuel while nuclear fission reactor uses uranium and plutonium as fuel. Besides, inherent design characteristics and driving condition of nuclear fusion reactor is different from those of nuclear fission reactor. Therefore, we cannot apply the regulation rules of nuclear fission reactor to nuclear fusion reactor without change and thus it is needed to development of the safety regulation concept which reflects the characteristics of nuclear fusion reactor. Safety regulation of nuclear fusion reactor employs deterministic approach until sufficient data are secured. However, regulation methodology of nuclear fusion reactor ...

British Library Electronic Table of Contents (United Kingdom)

An energy transfer and conversion model for high-temperature solar cavity receivers has been developed using the transport behaviour of solar radiation as described by the spectral radiative exchange factors. A Monte-Carlo ray-tracing method coupled with optical properties was adopted, to predict radiation characteristics of the solar collector system by calculating radiative exchange factors. A cavity receiver with a plano-convexo quartz window was proposed, based upon the directional characteristics of the focal flux and the redistribution effect of the quartz window. Parametric studies on the windowed receiver provided a more uniform flux distribution, higher efficiency and lower loss than the windowless receivers. The predicted results serve as a design reference for the solar receiver...

Energy Technology Data Exchange (ETDEWEB)

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

British Library Electronic Table of Contents (United Kingdom)

An experimental study was performed to investigate the heat transfer characteristics of the mixed convection flow through a horizontal rectangular channel where open-cell metal foams of different pore densities (10, 20 and 30 PPI) were situated. A uniform heat flux was applied at all of the bounding walls of the channel. For each of three values of the uniform heat flux, temperatures were measured on the entire surfaces of the walls. Results for the average and local Nusselt numbers are presented as functions of the Reynolds and Richardson numbers. The Reynolds number based on the channel height of the rectangular channel was varied from 600 to 33000, while the Richardson number ranged from 0.02 to 103, extending over forced, mixed and natural convection. Second important parameter that in...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) core loading during its ninth operating cycle was significantly different from that of previous cycles because of the presence of the Core Demonstration Experiment (CDE). The CDE consists of a number of axially blanketed fuel assemblies and internal blankets prototypic of advanced oxide cores in Liquid Metal Reactors (LMR). In preparation for the Cycle 9 reload design effort, a careful assessment of control rod worth and reactivity calculations for Cycles 1 through 8 was made. The goal of this study was to establish calculational biases and reduce uncertainties factored into the reload design calculations. These analyses helped assure that the operational objectives for Cycle 9 were met.

Energy Technology Data Exchange (ETDEWEB)

The thesis relates to an investigation done on greenhouse gases in coniferous forest soils. The production of nitrous oxide (N{sub 2}O) and carbon dioxide (CO{sub 2}), and the consumption of methane (CH{sub 4}) in a temperate forest soil were studied by a rapid and sensitive gas chromatographic (GC) method for analysing all three greenhouse gases at or below ambient levels. Gas fluxes were measured in soil incubation and lysimeter experiments. 15 soil samples were taken at random within a 100 m{sup 2} area in a Norway spruce forest stand (Picea abies). The fluxes of N{sub 2}O, CH{sub 4} and CO{sub 2} were measured under standardized laboratory incubation conditions to investigate spatial variability in relation to other factors such as nitrogen (N) mineralization rate, nitrification rate, organic carbon (OC), total N and pH. The effects of temperature, soil moisture content, and ammonium addition were also ...

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).

UK PubMed Central (United Kingdom)

The effects of a moderate-intensity static magnetic field (SMF) on osteoporosis of the lumbar vertebrae were studied in ovariectomized rats. A small disc magnet (maximum magnetic flux density 180 mT)...Full Text Available

International Nuclear Information System (INIS)

Heat transfer augmentation by straight grid spacers in rod bundles is studied for single phase flow and for post critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single phase flow is also examined. Governing heat transfer mechanisms are analyzed, and predictive formulations are established. For single phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. 18 refs.

International Nuclear Information System (INIS)

By revisiting previous definitions, we show that one can define an energy current operator that satisfies the continuity equation for a general Hamiltonian in one dimension. This expression is useful for studying electronic, phononic and photonic energy flow in linear systems and in hybrid structures. The definition allows us to deduce the necessary conditions that result in current conservation for general-statistics systems. The discrete form of the Fourier's law of heat conduction naturally emerges in the present definition.

International Nuclear Information System (INIS)

Bobbin-coil-type eddy current probes, which are conventionally used for nondestructive inspection of steam generator tubes in pressurized-water-type nuclear power plants, have poor detectability for circumferential flaws. Hence a new type of eddy current probe was proposed to detect effectively the magnetic flux component disturbed by a flaw and thus to eliminate the flaw direction dependency on the flaw detectability. In the course of development of the proposed method, structures of the probe were investigated based on the measurement of magnetic fields induced by exciting flat coils with several shapes. The new type of probe proposed here consists of differential pick-up coils detecting magnetic flux and exciting coils having a parallelogrammic shape, and its structure was fabricated experimentally in order to detect flaws independently of their directions. Nondestructive flaw detection tests was then conducted by using the probe. The ...

International Nuclear Information System (INIS)

The flux distributions and enhancement factors for various gas doser designs typically used in surface science applications and chemisorption studies have been calculated and compared. The following conclusions, which will aid the experimentalist in the choice of doser design, can be made. (1) The enhancement factor expected for a given doser can easily be derived from Fig. 2. (2) The optimum doser design is a multichannel array with a radius slightly larger than that of the sample, and a distance from the sample < 10% of the sample diameter. (Complications of this design are discussed.) (3) Because of space requirements, the sample--doser distance must sometime be > or =40% of the sample diameter, in which cases it is better to use a cosine emitter. A good, very simple doser design is described that consists of a small cosine emitter with a sample--doser distance of 1/2 the sample diameter. This provides an enhancement factor >50% of ...

International Nuclear Information System (INIS)

Axial offset anomaly (AOA) is caused by the deposition of crud on the fuel cladding of a PWR. When significant levels of crud build up on the cladding, boron can accumulate in the pores of the crud as a concentrated solution or solid phase, and cause the flux depression. Numerous studies have been conducted on the primary water chemistry to reduce the amount of crud in the primary circuit to avoid radioactivity buildup and unexpected power transition in the plant. However, experiments on the crud are restricted in the laboratory because the crud is a highly radioactive material. The objective of this study is to develop a test method for simulating the deposition of crud in a nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

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

DEFF Research Database (Denmark)

The National Survey and Cadastre - Denmark (KMS) has for several years produced gravity anomaly maps over the oceans derived from satellite altimetry. During the last four years, KMS has also conducted airborne gravity surveys along the coast of Greenland dedicated to complement the existing onshore gravity coverage and fill in new data in the very-near coastal area, where altimetry data may contain gross errors. The airborne surveys extend from the coastline to approximately 100 km offshore, along 6000 km of coastline. An adequate merging of these different data sources is important for the use of gravity data especially, when computing geoid models in coastal regions. The presence of reliable marine gravity data for independent control offers an opportunity to study procedures for the merging of airborne and satellite data around Greenland. Two different merging techniques, both based on collocation, are investigated in this paper. ...

CERN Document Server

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

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to provide a general view of wave energy resource assessment. First, a review of the origin of waves and the transformation they undergo as they propagate towards the coast through waters of decreasing depth is presented. Following this, the wave and wave-energy parameters and the statistics required for resource characterization are described. The various types of wave data and their usefulness for the present purposes are summarised. A common methodology for assessment of the wave energy resource is developed. Finally, a general description of the global open ocean resource is presented.

Environmental Research Database

DescriptionChamber studies have shown that biogenic organic compounds, including isoprene, are capable of producing secondary organic aerosol in significant quantities. This is surprising as isoprene and its photo-oxidation products have relatively high vapour pressures. However, it is very important as isoprene has the largest global emissions flux of any biogenic hydrocarbon, most of which is in the tropics. Despite this, secondary organic aerosol has been poorly studied in tropical regions with only [continued...

International Nuclear Information System (INIS)

The mine dumps that arise from the gold mining operations in South Africa are a potential source of high concentrations of radon (222"Rn). Studying the diffusion of radon and the emanation from the soil will help to deduce the radon flux from these dumps to identify the problem areas for rehabilitation. This study describes measurements of the emanation coefficient and the modelling of the depth profile of the radon activity concentration, which is compared to a depth profile that was measured on such a mine dump. Emanation coefficients ranging from 0.13 to 0.39 have been obtained.

Energy Technology Data Exchange (ETDEWEB)

The objective of the present study is to reveal thermal characteristic of microcapsulated lauric acid slurry in circular pipe. Test were performed with microcapsulated lauric acid slurry in a heating test section with a constant heat flux boundary condition. Local Nusselt number and the effective thermal capacity were measured. As the size of microcapsulated lauric acid were increased, local Nusselt number of microcapsulated lauric acid slurry were increased. The effective thermal capacity of microcapsulated lauric acid slurry was 0.5 times than it of water.

Energy Technology Data Exchange (ETDEWEB)

An experimental rig was set up to study the performance of a thermal storage unit using stearic acid as the heat storage medium. The unit mainly consists of an electrical heating rod and an outer tube, and the space between is an annulus that is filled with stearic acid. The thermal performance of the unit is measured, and the heat transfer characteristics of the melting processes of stearic acid are studied under different heat flux conditions to determine the influence of heat flux on the melting processes. A new type of fin is designed and fixed to the electrical heating rod to enhance the thermal response of the stearic acid. The experimental results show that the fin can improve the heat transfer of the melting process of the thermal storage unit greatly. The equivalent thermal conductivity of the PCM can be augmented by a factor up to 3. The analysis of the experimental results shows that the ...

Energy Technology Data Exchange (ETDEWEB)

Performance assessments for the Area 5 Radioactive Waste Management Site on the Nevada Test Site have used three different mathematical models to estimate Rn-222 flux density. This study describes the performance, uncertainty, and sensitivity of the three models which include the U.S. Nuclear Regulatory Commission Regulatory Guide 3.64 analytical method and two numerical methods. The uncertainty of each model was determined by Monte Carlo simulation using Latin hypercube sampling. The global sensitivity was investigated using Morris one-at-time screening method, sample-based correlation and regression methods, the variance-based extended Fourier amplitude sensitivity test, and Sobol's sensitivity indices. The models were found to produce similar estimates of the mean and median flux density, but to have different uncertainties and sensitivities. When the Rn-222 effective diffusion coefficient was estimated using ...

International Nuclear Information System (INIS)

Experimental results of compatibility tests on ceramics-metal bonded structures performed under high heat flux conditions in splash test apparatus are reported. Emphasis is placed on results of the channel wall design and its critical operating conditions under MHD environment. The module design of one cold type and three semihot type insulators have been tested. These materials were Al_2O_3, Al_2MgO_4, LaAlO_4, MgO and Sialon ceramics. The methods of cold type ceramics-metal bonding structure were studied on Al_2O_3 and Spinel spray coating technology. The refractory metallizing and ceramics-metal graded structure manufactured by HIP technologies were applied to bonding between the MgO or LaAlO_4 and metallic cooling system. The Sialon non-bonding structure was tested with mechanical supported cooling system by shrinc fitting method. The results indicated that the bonding structures made of the MgO(MG-S) with Copper and Fe-Ni Alloy relaxation ...

British Library Electronic Table of Contents (United Kingdom)

A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...

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)

Various SST indices in the Indo-Pacific region have been proposed in the literature in light of a long-range seasonal forecasting of the Indian Summer Monsoon (ISM). However, the dynamics associated with these different indices have never been compared in detail. To this end, the present work re-examines the variabilities of ISM rainfall, onset and withdrawal dates at interannual timescales and explores their relationships with El Ni?o-Southern Oscillation (ENSO) and various modes of coupled variability in the Indian Ocean. Based on recent findings in the literature, five SST indices are considered here: Ni?o3.4 SST index in December?January both preceding [Nino(?1)] and following the ISM [Nino(0)], South East Indian Ocean (SEIO) SST in February?March, the Indian Ocean Basin (IOB) mode in ...

British Library Electronic Table of Contents (United Kingdom)

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

International Nuclear Information System (INIS)

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

CERN Document Server

The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general properties of the ISM in this direction. ...

International Nuclear Information System (INIS)

We study the spectral evolution of pulsar wind nebulae (PWNe) taking into account the energy injected when they are young. We model the evolution of the magnetic field inside a uniformly expanding PWN. Considering time-dependent injection from the pulsar and coolings by radiative and adiabatic losses, we solve the evolution of the particle distribution function. The model is calibrated by fitting the calculated spectrum to the observations of the Crab Nebula at an age of a thousand years. The spectral evolution of the Crab Nebula in our model shows that the flux ratio of TeV #gamma#-rays to X-rays increases with time, which implies that old PWNe are faint in X-rays, but not in TeV #gamma#-rays. The increase of this ratio is because the magnetic field decreases with time and is not because the X-ray emitting particles are cooled more rapidly than the TeV #gamma#-ray emitting particles. Our spectral evolution model matches the observed rate of ...

Science.gov (United States)

The present study investigates the effect of the shear rate-dependent thermal conductivity of non-Newtonian fluids on the heat transfer enhancement in a pipe flow. The constant heat flux as thermal boundary condition was adopted in the thermally developed region. The present analytical results show the heat transfer enhancement over those of a shear rate-independent thermal conductivity fluid. The heat transfer coefficient ratio (h/h{sub 0}) linearly increase with the non-dimensional average velocity difference which is the product of the shear rate-dependence of the thermal conductivity and wall-shear rate.

Science.gov (United States)

Laser Doppler velocimetry and other photometric techniques are evaluated for measuring the average particle velocity in an ensemble of free-falling particles. The ability to obtain measurements in the presence of a radiant flux as high as 0.6 MW/m/sup 2/ was part of the evaluation. Optically dissimilar particles with diameters ranging from 0.1 mm to 1 mm were used in the study. Experimental results indicate that ensembles of particles do not behave as single isolated particles. The particle motion is dependent on particle volume fraction, and is quite unstable for falls greater than one meter.

CERN Document Server

We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a brightness temperature limit of about 10.000 K, and an expected dynamic range in future VLBI maps of better than 1.000.000, the impact of SKA on the research of compact extragalactic radio sources and their energetic jets will be very strong. We discuss some consequences, including a possible combination of SKA with future space VLBI missions.

International Nuclear Information System (INIS)

Compositions (oligomers with suitable properties and Al, Fe, Cu, Ta, W powders) were hardured by the flux of accelerated electrons at 10 mA beam current and 1.5 MeV energy. Dielectric and mechanical properties of metal-filled polymeric compositions as well as their radioply sicl properties in SHF-range are studied. It is shown that the produced compositions belong tot he absorbing protective materials in which the protection effect is mainly achieved through the absorption losses. 6 refs.; 3 tabs.

CERN Document Server

Heat exchange during laminar flow is studied at the fracture scale on the basis of the Stokes equation. We used a synthetic aperture model (a self-affine model) that has been shown to be a realistic geometrical description of the fracture morphology. We developed a numerical modelling using a finite difference scheme of the hydrodynamic flow and its coupling with an advection/conduction description of the fluid heat. As a first step, temperature within the surrounding rock is supposed to be constant. Influence of the fracture roughness on the heat flux through the wall, is estimated and a thermalization length is shown to emerge. Implications for the Soultz-sous-For\\^{e}ts geothermal project are discussed.

International Nuclear Information System (INIS)

In the present study, a subcooled boiling loop with an annular flow on the electrically heated rod was used to make an experimental approach to investigate the effects of induced instability by the subcooled boiling on vibration of the rod in different subcooled conditions. The results show the intensive subcooled-boiling-induced vibration (SBIV) which is highly depend on dynamic force generated by fast vapor bubbles growth and collapse whilst they still attach to, or slide along, the heating surface at high loading heat fluxes. These behaviors were strongly influenced by the conditions of subcooling temperature, flow rate and linear power density. (author)

International Nuclear Information System (INIS)

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

CERN Document Server

We provide a both qualitative and quantitative comparison among different approaches aimed to solve the problem of non-linear diffusive acceleration of particles at shocks. In particular, we show that state-of-the-art models (numerical, Monte Carlo and semi-analytical), even if based on different physical assumptions and implementations, for typical environmental parameters lead to very consistent results in terms of shock hydrodynamics, cosmic ray spectrum and also escaping flux spectrum and anisotropy. Strong points and limits of each approach are also discussed, as a function of the problem one wants to study.

International Nuclear Information System (INIS)

The aim of this study is to clarify the radon behavior in the soil at the waste rock yards of uranium mine. We have developed an apparatus for measuring radon diffusion coefficient in soil under the control of soil temperature. The radon diffusion coefficients changed suddenly around the soil temperature of 0degC. The radon diffusion coefficients in dry soil have little temperature dependency, and were comparable coefficients obtained by empirical formula of Rogers and Nielson. To study the restraint effect of radon exhalation by covering with bentonite on soil, we carried out the measurements and the calculations by using one-dimensional transport model of atmosphere and soil. The decrease of radon exhalation rate was 2.9 Bq m"-"2s"-"1 when soil covered with the bentonite of 5 cm thick. The radon concentrations in snow cover and the radon flux from the snow surface were measured at the waste rock yard in Ningyo-toge ...

Science.gov (United States)

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

UK PubMed Central (United Kingdom)

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

UK PubMed Central (United Kingdom)

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

Science.gov (United States)

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

Science.gov (United States)

In the IEEE Marine Technology Society OCEANS 2009 Conference, Biloxi. October 26-29, 2009. Biloxi, MS. Al-Hamdan, M.; Estes, M.; Quattrochi, D.; Thom, R.; ...

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

Science.gov (United States)

Ocean thermal energy conversion (OTEC) plants discharge large volumes of cold water into the upper ocean. A three-dimensional, limited-area model was developed to investigate the regional influence of the far-field effluent plume created by the negatively buoyant discharge. The model was applied to discharges from a 40-MW/sub e/ OTEC plant into coastal waters characterized by various ambient ocean conditions. A typical ambient temperature structure and nutrient distribution, as well as the behavior of the effluent plume itself, were strongly modified by the discharge-induced circulation. Although temperature perturbations in the plume were small, upward entrainment of nutrients from below the thermocline was significant. The regional influence of discharges from an 80-MW/sub e/ OTEC plant, the interactions between the discharges from two adjacent 40-MW/sub e/ OTEC plants, and the effects of coastal boundary and bottom ...

Energy Technology Data Exchange (ETDEWEB)

Adenosine triphosphate (ATP) is an indicator of living biomass in marine particulates. This report details the method used by Lawrence Berkeley Laboratory to analyze particulate ATP in samples taken from oligotrophic, tropical ocean waters. It represents a synthesis of previously published methods.

UK PubMed Central (United Kingdom)

Picocyanobacteria of the genus Synechococcus are important contributors to marine primary production and are ubiquitous in the world's oceans. This genus is genetically diverse, and...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This grant has focused on the study of several aspects of electron kinetics in low pressure plasmas. Entirely new effects arise from the fact that the electron kinetics is governed by non-local effects, in which the electron distribution function is not equilibrium with the local electric field but is governed by spatial transport effects. In this grant, we were able to demonstrate several previously un-studied effects which are a direct result of the nonlocal transport. These are: (1) The existence of a ''convective cell' in electron phase space. The phenomenon was observed and studied in CW plasma conditions. (2) The occurrence of non-collisional cooling of electrons through an effect known as ''diffusive cooling''.

British Library Electronic Table of Contents (United Kingdom)

The principal objective of this study is to formulate an effective optimal fuel management strategy for the TRIGA MARK II research reactor at AERE, Savar. The core management study has been performed by utilizing four basic types of information calculated for the reactor: criticality, power peaking, neutron flux and burnup calculation. This paper presents the results of the burnup calculations for TRIGA LEU fuel elements. The fuel element burnup for approximately 20 years of operation was calculated using the TRIGAP compute code. The calculation is performed in one-dimensional radial geometry in TRIGAP. Inter-comparison of TRIGAP results with other two calculations performed by MVP-BURN and MCNP4C-ORIGEN2.1 show very good agreement. Reshuffling at 20,000MWh step provides the highest core l...

International Nuclear Information System (INIS)

This paper reports on a series of experiments performed to examine the ability of ion beam assisted thermal deposition to produce good adhesion of Au metallization on GaAs left-angle 100 right-angle substrates. A study of the influence of Ar ion-assisted thermal deposition of the Au films as well as in situ pre-sputtering of the GaAs surface with low-energy Ar ions prior to thermal deposition, shows that strong adhesion can be achieved without resorting to chemical cleaning. The substrate temperature and the relative flux of Ar ions to incident Au atoms were varied in order to correlate these parameters with film adhesion. The interfaces of films processed under these various conditions were examined by XTEM, RBS and XPS. Orientation texture was studied by x-ray diffraction (XRD).

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 consumed for heating the soil and the lower atmosphere. Where moisture is available, evaporation is one of the key components of the surface energy ...

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Numerical solutions given by a vorticity-velocity method are presented for combined free and forced laminar convection in the thermal entrance region of a horizontal rectangular channel without the assumptions of large Prandtl number and small Grashof number. The channel wall is heated with a uniform wall heat flux. Typical developments of temperature profile, secondary flow, and axial velocity at various axial positions in the entrance region are presented. Local friction factor and Nusselt number variations are shown for Rayleigh numbers Ra = 10{sup 4}, 3 {times} 10{sup 4}, 6 {times} 10{sup 4}, and 10{sup 5} with the Prandtl number as a parameter. The solution for the limiting case of large Prandtl number and small Grashof number obtained from the present study confirms the data of existing literature. It is observed that the large Prandtl number assumption is valid for Pr = 10 when Ra {le} 3 {times} 10{sup 4} but for a larger Prandtl number ...

International Nuclear Information System (INIS)

Calculations have been made to determine the production of "1"8"8W from "1"8"6W in several US fission reactor systems, e.g., Fast Flux Test Facility (FFTF), the High Flux Isotope Reactor (HFIR), and the Advanced Test Reactor (ATR). Important input to these calculations are the cross-section parameters for "1"8"6W, "1"8"7W, and "1"8"8W. Only two values have been measured for "1"8"7W and none for "1"8"8W. Consequently, results from integral measurements play a crucial role in determining the "1"8"7W and "1"8"8W values. This has been studied for irradiations in the FFTF and the Oregon State Univ. (OSU) research reactor. Short irradiation of enriched "1"8"6W in both the FFTF and the OSU reactors have produced #mu#Ci/g quantities of "1"8"8W/"1"8"8Re. Measurements were made of the "1"8"8W gamma ray emission. These results were incorporated with other available data to provide more accurate "1"8"8W calculations in fission reactor ...

British Library Electronic Table of Contents (United Kingdom)

Mixed convection heat transfer from longitudinal fins inside a horizontal channel has been investigated in the natural convection dominated region for a wide range of Rayleigh numbers and different fin heights and spacings. An experimental parametric study was made to investigate effects of fin spacing, fin height and magnitude of heat flux on mixed convection heat transfer from rectangular fin arrays heated from below in a horizontal channel. The optimum fin spacing to obtain maximum heat transfer has also been investigated. During the experiments constant heat flux boundary condition was realized and air was used as the working fluid. The velocity of fluid entering channel was kept nearly constant (0.02win0.025m/s) using a flow rate control valve so that Reynolds number was always about ...

Energy Technology Data Exchange (ETDEWEB)

With using artificial neural networks (ANNs), an analytical study related to the heated length effect on critical heat flux (CHF) has been carried out to make an improvement of the CHF prediction accuracy based on local condition correlations or table. It has been carried out to suggest a feasible criterion of the threshold length-to-diameter (L/D) value in which heated length could affect CHF. And within the criterion, a L/D correction factor has been developed through conventional regression. In order to validate the developed L/D correction factor, CHF experiments for various heated lengths have been carried out under low and intermediate pressure conditions. The developed threshold L/D correlation provides a new feasible criterion of L/D threshold value. The developed correction factor gives a reasonable accuracy for the original database, showing the error of -2.18% for average and 27.75% for RMS, and promising results for new experimental ...

Energy Technology Data Exchange (ETDEWEB)

A novel scheme is proposed to drive a low-power subcritical fuel assembly by means of a long Cylindrical Radially-convergent Inertial Electrostatic Confinement (CRIEC) used as a neutron source. The concept is inherently safe in the sense that the fuel assembly remains subcritical at all times. Previous work has been done for the possible implementation of CRIEC as a subcritical assembly driver for power reactors. However, it has been found that the present technology and stage of development of IEC-based neutron sources can not meet the neutron flux requirements to drive a system as big as a power reactor. Nevertheless, smaller systems, such as research and training reactors, could be successfully driven with levels of neutron flux that seem more reasonable to be achieved in the near future by IEC devices. The need for custom-made expensive nuclear fission fuel, as in the case of the TRIGA reactors, is eliminated, and the CRIEC presents ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

The Monte-Carlo method and experimental methods were used to determine the neutron fluxes in the irradiation channels of the Ghana Research Reactor -1. The MCNP5 code was used for this purpose to simulate the radial and axial distribution of the neutron fluxes within all the ten irradiation channels. The results obtained were compared with the experimental results. After the MCNP simulation and experimental procedure, it was observed that axially, the fluxes rise to a peak before falling and then finally leveling out. Axially and radially, it was also observed that the fluxes in the centre of the channels were lower than on the sides. Radially, the fluxes dip in the centre while it increases steadily towards the sides of the channels. The results have shown that there are flux variations within the irradiation channels both axially and radially. (au)

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Two criteria, geologic stability and barrier effectiveness, form the basis of the Subseabed Disposal Program's site qualification plan to evaluate the ocean basins and identify those regions having characteristics most favorable for containment of radioactive waste. Stability criteria are used to define those regions least likely to be disturbed by tectonic forces or oceanographic changes during the lifetime of a waste repository. Barrier criteria define those lithologies most likely to form an effective barrier to the release of radionuclides. Two north Pacific regions and three north Atlantic regions (PAC I and II and ATL I, II, and III, respectively) have thus far been selected for further investigation based on the site qualification plan. The PAC I region, centered on the Shatsky Rise in the northwest Pacific, has been subdivided into areas and locations on the basis of an exhaustive review of data available in the archives of national and ...

Energy Technology Data Exchange (ETDEWEB)

A thermohydraulic study of MTR fuel element is presented as a basic requirement for the development of an irradiation facility for testing fuel elements. A computer code named 'Thermo' has been developed for this purpose, which can stimulate different working conditions, such as, cooling, power elements and neutron flux, performing all pertinent thermohydraulic calculations. Thermocouples were used to measure the temperature gradients of the cooling fluid throughout the IEAR-1 reactor core. All experimental data are in good agreement with the theoretical model applied in this work. Finally, a draft of the proposed facility and its safety system is presented. (author)

International Nuclear Information System (INIS)

The LWR fuel performance analysis computer code, FRAPCON-1, are evaluated to investigate the performance of CANDU fuel elements loaded in Wolsung-1 reactor. The FRAPCON-1 models of neutron flux depression in fuel and of fuel-to-cladding heat transfer are modified, and the validity of fission gas release model for CANDU fuel is evaluated. And the heavy water properties are provided in calculating the heat transfer coefficient between cladding and coolant. By using the modified code, FRAPCON-1-CSK, the sensitivity studies are carried out for Wolsung-1 fuel element design parameters. The performance analysis is also performed for Wolsung-1 fuel elements. The calculated results are discussed in terms of LWR fuel design criteria because of unavailability of CANDU fuel design criteria. (Author).

International Nuclear Information System (INIS)

The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.

British Library Electronic Table of Contents (United Kingdom)

Academic, government, and industrial field researchers have generated a significant database of field studies of the volatility of soil applied fumigants. However, limited work exists in validating physical models against field volatility data sets and fully exploring the volatility parametric response surface. Field studies quantifying atmospheric flux for soil fumigants 1,3-dichloropropene and chloropicrin are validated against the United States Department of Agriculture (USDA Salinity Laboratory) soil physics model CHAIN_2D that was modified specifically for agronomic uses of soil fumigants. Comparison between model predictions and field observations for six unique field trials in five different states indicate that CHAIN_2D effectively captures the magnitude and duration of fumigant em...

International Nuclear Information System (INIS)

A core-wide in-phase neutron flux oscillation, which took place, for example, at LaSalle-2 in the USA in 1988, is one of the nuclear-coupled thermal hydraulic instabilities in boiling water reactors (BWRs). In this study, an analysis has been performed focusing on the excitation of this type of instability in BWRs due to seismically induced resonance, within the scope of a point kinetics model. For this purpose, the TRAC-BF1 code has been modified to take into account the external acceleration in addition to gravity. As a result of this analysis, it is shown that reactivity insertion can occur accompanied by in-surge of the coolant into the core resulting from excitation. It is also shown that the amount of reactivity inserted largely depends on the degree of stability of the initial state and the amplitude of the seismic wave, whose frequency is the same as the characteristic frequency of the instability. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Abstract Carbon climate, like other environmental sciences, has been changing. Large scale synthesis studies are becoming more common. These synthesis studies are often conducted by science teams that are geographically distributed and on data sets that are global in scale. A broad array of collaboration and data analytics tools are now available that could support these science teams. However, building tools that scientists actually use is difficult. Also, moving scientists from an informal collaboration structure to one mediated by technology often exposes inconsistencies in the understanding of the rules of engagement between collaborators. We have developed a scientific collaboration portal, called fluxdata.org, which serves the community of scientists providing and analyzing the globa...

Energy Technology Data Exchange (ETDEWEB)

Small circular and noncircular channels are representative of flow passages in compact evaporators and condensers. This paper describes results of an experimental study on heat transfer to the flow boiling of refrigerant- 12 in a small circular tube of diameter = 2.46 mm. The objective of the study was to assess the effect of channel size on the heat transfer coefficient and to obtain additional insights relative to the heat transfer mechanisms. The flow channel was made of brass and had an overall length of 0.9 m. The channel wall was electrically heated, and temperatures were measured on the channel wall and in the bulk fluid stream. Voltage taps were located at the same axial locations as the stream thermocouples to allow testing over an exit quality range of 0.21 to 0.94 and a large range of mass flux (63 to 832 kg/m{sup 2}s) and heat flux (2.5 to 59 kW/m{sup 2}). Saturation pressure was nearly ...

Energy Technology Data Exchange (ETDEWEB)

Among the membrane filtration techniques, continuous cross-flow ultrafiltration (UF) is an innovative method to separate solid/liquid or liquid/liquid phases at a lower pressure of 5--150 psi compared to reverse osmosis (RO) in which the applied pressure is an order of magnitude higher. Recently, attempts have been made to combine processes of UF and other treatments for many applications. However, there is very little knowledge about the filtration process which combined coagulation and UF, and very few attempts have been made to apply coagulated UF to the treatment of fuel oil contaminated water. During the UF treatment of organic contaminants rapid declines in flux will occur due to the membrane fouling. Oil as a foulant plants an important role in the flux decrease. However, there are very limited pretreatment processes which can effectively remove fuel oil from water and hence solve the fouling problem. The purpose of the ...

Energy Technology Data Exchange (ETDEWEB)

This work concerns the development of nuclear energy and nuclear waste management in particular. Two parts of this study can be distinguished. In the first part (theoretical), a thorium-plutonium fuel based on MOX and dedicated for PWR was investigated in order to transmute plutonium in a potentially low waste fuel cycle. It was shown that this type of fuel is not regenerative but could be used for a transition to the industrial thorium fuel cycle without building new reactors. Thanks to moderated neutron spectra and high loaded actinide mass in the core, U-233 is quickly created ({approx}300 kg/y) for a loss of about {approx}1200 kg of fissile plutonium. In the second part (experimental), we have developed and built a new reaction chamber to measure neutron cross sections of actinides by alpha-gamma spectroscopy. This experimental device (in principle transportable) was commissioned in the high flux reactor of ILL Grenoble. Neutron ...

Energy Technology Data Exchange (ETDEWEB)

Numerical simulations are used to predict the migration of radionuclides from the disposal units at Material Disposal Area G through the vadose zone and into the main aquifer in support of a radiological performance assessment and composite analysis for the site. The calculations are performed with the finite element code, FEHM. The transport of nuclides through the vadose zone is computed using a three-dimensional model that describes the complex mesa top geology of the site. The model incorporates the positions and inventories of thirty-four disposal pits and four shaft fields located at Area G as well as those of proposed future pits and shafts. Only three nuclides, C-14, Tc-99, and I-129, proved to be of concern for the groundwater pathway over a 10,000-year period. The spatial and temporal flux of these three nuclides from the vadose zone is applied as a source term for the three-dimensional saturated zone model of the main aquifer that underlies the site. The ...

Energy Technology Data Exchange (ETDEWEB)

The recently completed ''Deep River Study, Lower Mississippi River'' sponsored by the ''Governor's Task Force on Deep-Draft Vessel Access to the Lower Mississippi River'' contained the following recommended program: Dredge the present 40 foot deep channel to 45 feet initially from the Gulf via Southwest Pass to Mile 172 AHP to provide for two-way navigation of the deep draft vessels that would serve the forecasted most likely level of waterborne commerce (Alternative 9). Plan and seek authorization to further deepen the channel in stages to 55 feet in the future should actual increases in commerce equal the high level level of commerce (Alternative 11). Put into operation, as soon as possible, facilities for loading and topping-off grain ships midstream and topping-off coal carriers in the Gulf in order to attract and establish patterns of trade in large ships. The South Pass Bulk ...

International Nuclear Information System (INIS)

The physicochemical forms and partitioning of corrosion products released from stainless steel upon exposure to selected environmental conditions is the subject of this investigation. This report describes the influence of calcareous sediment on the rate of release and fate of corrosion products produced when neutron-activated stainless steel specimens were exposed to a Globigerina ooze taken from the Northeast Pacific Ocean. The calcareous ooze used in this study consists largely of planktonic formanifera tests and was found to be about 90% CaCO_3. The trace metal content of this sediment was typical of average deep-sea carbonate sediments, and the ratios of trace elements to Ti were not remarkably different from a coastal clayey silt or a Northeast Pacific pelagic red clay. Most (>80%) of the trace metals extracted by sequential chemical treatment were associated with reductant-soluble materials, i.e., amorphous Mn and Fe oxides, or were ...

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 ...

International Nuclear Information System (INIS)

In order to assess various core parameters a reference equilibrium core with Low Enriched Uranium (LEU) fuel for Pakistan Research Reactor (PARR-1) was assembled. Due to increased volume of reference core, the average neutron flux reduced as compared to the first higher power operation. To get a higher neutron flux an irradiation facility was created in centre of the reference equilibrium core where the advantage of the neutron flux peaking was taken. Various low power experiments were performed in order to evaluate control rods worth and neutron flux mapping inside the core. The neutron flux inside the central irradiation facility almost doubled. With this arrangement reactor operation time was cut down from 72 hours to 48 hours for the production of the required specific radioactivity. (author)

CERN Document Server

Recently we have made measurements of thermonuclear burst energetics and recurrence times which are unprecedented in their precision, largely thanks to the sensitivity of the Rossi X-ray Timing Explorer. In the "Clocked Burster", GS 1826-24, hydrogen burns during the burst via the rapid-proton (rp) process, which has received particular attention in recent years through theoretical and modelling studies. The burst energies and the measured variation of alpha (the ratio of persistent to burst flux) with accretion rate strongly suggests solar metallicity in the neutron star atmosphere, although this is not consistent with the corresponding variation of the recurrence time. Possible explanations include extra heating between the bursts, or a change in the fraction of the neutron star over which accretion takes place. I also present results from 4U 1746-37, which exhibits regular burst trains which are interrupted by "out of phase" bursts.

International Nuclear Information System (INIS)

Real-time neutron powder diffraction and small-angle scattering techniques have been developed on the TOF diffractometer DN-2 at the IBR-2 pulsed reactor at JINR (Dubna) with a total flux on the sample of 10"7 neutrons cm"-"2s"-"1 and a resolution of about 1%. A special arrangement of the detector system ensures a high counting rate of diffracted neutrons. Depending upon sample type and experimental conditions, the measuring time t_s of one neutron pattern varies from a few minutes to several seconds. The performance of the diffractometer is discussed and typical data are shown to demonstrate current achievements using real-time techniques at a pulsed reactor. (orig.).

Energy Technology Data Exchange (ETDEWEB)

By means of neutron diffraction, using the standard polycrystalline sample of Al{sub 2}O{sub 3}, measurements on three (of four spectrometers) already installed in the front of horizontal channels of MARIA reactor have been performed. Basing on these experiments as well as on activation measurements carried out earlier, the fluxes of monoenergetic neutrons have been estimated. These experiments allowed to determine (for a given geometry and kind of monochromators chosen) the resolution efficiency of instruments and high order contamination in the reflected beam. With the help of polycrystalline vanadium and TbBr{sub 3} sample, the possibility of studies using the inelastic scattering process have been tested. (author) 7 refs, 15 figs, 7 tabs

Energy Technology Data Exchange (ETDEWEB)

Mobility reduction induced by the growth and metabolism of bacteria in high-permeability layers of heterogeneous reservoirs is an economically attractive technique to improve sweep efficiency. This paper describes an experimental study conducted in sandpacks using an injected bacterium to investigate the strength and stability of microbial plugs in porous media. Successful convective transport of bacteria is important for achieving sufficient initial bacteria distribution. The chemotactic and diffusive fluxes are probably not significant even under static conditions. Mobility reduction depends upon the initial cell concentrations and increase in cell mass. For single or multiple static or dynamic growth techniques, permeability reduction was approximately 70% of the original permeability. The stability of these microbial plugs to increases in pressure gradient and changes in cell physiology in a nutrient-depleted environment needs to be ...

Energy Technology Data Exchange (ETDEWEB)

The spray and combustion development in a single-cylinder, direct-injection diesel engine equipped with optical access was examined using a number of complementary techniques. A laser imaging system, based around a pulsed copper-vapour laser synchronised to an intensified CCD camera, was used to obtain images of the four fuel sprays prior to combustion, and to determine the tip penetration of each spray as a function of crankangle. The surface heat flux to the wall of the piston bowl was measured by placing a fast-response thermocouple at the impingement point of one of the sprays, and a two-colour imaging system was used to obtain digital images of the flame temperature and equivalent soot distribution in the cylinder. (author)

Energy Technology Data Exchange (ETDEWEB)

The development of central receiver technology for the production of electricity is reasonably well established. One possible direction for future research and development efforts funded by the Department of Energy is high-temperature, high-performance systems. In this paper, the performance of central receiver systems is investigated for a range of heliostat sizes, field configurations, plant sizes, and receiver temperatures. The maximum plant efficiency achievable in a central receiver system that uses simple cavity geometry is shown for a range of receiver temperatures. The impact of changes in heliostat size, field packing density, and canting and focusing strategies on system efficiency are investigated over a range of plant sizes. The results of the study underscore the importance of accommodating high absorber plane fluxes in order to efficiently produce working temperatures at or above 1200/sup 0/C.

Science.gov (United States)

In this paper we study theoretically a pulsed corona discharge plasma in air at atmospheric pressure. A self consistent one-dimensional model, using a flux-corrected transport numerical scheme, is presented to achieve it. The charged particle kinetics in this model are described by one-dimensional continuity equations coupled with Poisson's equations. The spatio-temporal local field, charge density variations and the velocity profile of an ionizing front are calculated to describe the dynamical behavior of corona discharge plasmas. The simulation results of a wire-in-cylinder corona discharge plasma explain the physical mechanisms of discharge processes. These results may also be apply to obtain the optimizing parameters for designing the plasma reactor.

International Nuclear Information System (INIS)

Decay heat removal capability under boiling condition was studied using an LMFBR fuel subassembly mockup loop. The sodium flow was driven by natural convection through the loop in which was installed a 37-pin bundle heated electrically over a length of 45 cm. The heat flux furnished by the pins was increased stepwise, upon which the two-phase flow regime changed from bubble to slug flow and then to annular or annular mist flow. Dryout occurred even in slug flow regime, but only momentarily, and permanent dryout was not observed before establichment of annular flow. A suitable criterion for permanent dryout is considered to be 0.5 average exit sodium vapor quality. The results indicated that upon occurrence of sodium boiling, the coolability of fuel subassembly would be maintained by natural convection after reactor shutdown. (author).

CERN Document Server

Cosmic ray antiprotons provide an important probe for the study of cosmic ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. The ARGO-YBJ experiment is observing the Moon shadow with high statistical significance at an energy threshold of a few hundred GeV. Using all the data collected until November 2009, we set two upper limits on the antip/p flux ratio: 5% at an energy of 1.4 TeV and 6% at 5 TeV with a confidence level of 90%. In the few-TeV range the ARGO-YBJ results are the lowest available, useful to constrain models for antiproton production in antimatter domains.

Energy Technology Data Exchange (ETDEWEB)

The utilization of electrically heated rods for the simulation of nuclear fuel pins represents a generally adopted method by the nuclear industry to study thermalhydraulic problems. Usually its is necessary to determine the time variation of the electric linear power 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 observed in the nuclear fuel pin. The present work analyzes the limits of the usually adopted simulation methods and shows a manner to obtain the required electrical linear power that reduces oscillations and yields accurate results for the thermal conditions of the rod surface wall. (author). 5 refs, 5 figs, 1 tab.

British Library Electronic Table of Contents (United Kingdom)

This paper aims to study fundamentally the impacts of membrane properties on the reactive dye removal from dye/salt mixtures by nanofiltration membranes. To begin with, two types of nanofiltration membranes of similar pore size, namely asymmetric cellulose acetate membrane and thin-film composite polyamide membrane were fabricated, and their key physical, chemical and performance properties were characterized. After that, these resultant membranes were employed to perform dye removal experiments with aqueous solutions of reactive black 5 and NaCl under different operational parameters. The dye removal rate and steady permeate flux were determined and correlated with the measured membrane properties. It was found that there were significant differences between the dye removal performances o...

Science.gov (United States)

Forced convective heat transfer in a cross-corrugated channel solar air heater has been studied experimentally using air as a working fluid. The channel was formed by two transversely positioned corrugated sheets and two flat thermally insulated side walls. One corrugated sheet was heated by a radiant heater, while the other was thermally insulated. The fluid velocity and temperature, and the wall temperature and the local heat flux across the heated corrugated sheet were measured for a variety of operating flow rates. Experimental results for the channel geometry have yielded the correlation Nu = 0.0743 (Re)[sup 0.76]. This heat-transfer coefficient is about 2.8 times that of a smooth flat channel. The experiments showed that local heat transfer rate was smaller on the valley of the corrugation than that on the peak. The ratio of the local heat transfer rates on the two locations was related to the Reynolds number.

International Nuclear Information System (INIS)

Shadow effect was used for investigating damage of uranium dioxide monocrystal. The dependence of shadow minimum parameters on fluence of "2"2Ne ions with 172 MeV energy was followed when detecting fission fragments. Ion dose responsible for sufficient microdamage of lattice structure, included into the classification of heavy ion damage effect on monocrystals was determined. The problem of radiation intensity effect on the character of occurred damages was studied. It was established that macroscopic sample failure, caused by generation of considerable mechanical stresses in monocrystal under beam effect could be observed along with microdamages of lattice structure at ion flux density >10"1"2 cm"-"2Xs"-"1.

British Library Electronic Table of Contents (United Kingdom)

Heat pipes, loop heat pipes (LHP), and capillary pumped loops (CPL) have already proven their potential to remove high heat fluxes from a small electronic device and transport the heat to a heat sink that is large enough to transfer it into the ambient air. We introduce a novel two-loop system similar in design to CPLs but with an additional buoyancy-driven fluid loop. Non-degassed methanol is used as a working fluid. Key benefits compared to LHPs and CPLs are easy filling procedure, easy startup, and the tolerance toward noncondensable gases in the fluid. The amount of fluid in the system can be varied over a broad range without affecting the heat transfer performance. Three different inverted-meniscus-type evaporators have been employed in this study. A maximum evaporator heat transfer r...

International Nuclear Information System (INIS)

Water-based epoxy sealants were examined during a 2-year period to determine their effectiveness as barriers to radon release in uranium mines. Radon emanation rates from uranium ore samples were monitored for extended periods in the laboratory before and after sealant application. Reduction of radon flux due to the coating of lab samples was approximately 80 percent. Test chambers in a dormant uranium mine were monitored to determine both short and long-term barrier effectiveness. These field studies of the sealants indicated reductions greater than 50 percent relatively soon after application and nearly 75 percent more than 1 year later. An unexpected complication to early monitoring in the form of a large radon emanation increase, believed due to added moisture, is discussed.

Energy Technology Data Exchange (ETDEWEB)

From optical point of view and due to the magnetic interaction of the cold neutrons with the unpaired electron shell, magnetic materials hae a neutron spin-dependent refractive index n[sup +] [spin up] and n[sup -] [spin down]. Magnetic media such as Fe, Co and Ni react like birefringent uniaxial crystals in ordinary optica. n[sup +] and n[sup -] are the equivalent of the ordinary and extraordinary refractive indices. The specular reflection of spin polarized neutrons which is due to the discontinuity of the magnetic induction at the surface of the ferromagnet is a sensitive probe of surface and interface magnetism. We shall first give the background of the art of polarized neutron optics. Secondly, some recent examples from surface and interface magnetism will be given to illustrate the power of this technique such as the magnetic coupling in thin films and multilayers and flux penetration in superconductors. (orig.).

International Nuclear Information System (INIS)

In the safety assessment of a high-level radioactive waste (HLW) disposal system, it is required to estimate radiological impacts on future human beings arising from potential radionuclide releases from a deep repository into the surface environment. In order to estimated the impacts, a biosphere model is developed by reasonably assuming radionuclide migration processes in the surface environment and relevant human lifestyles. It is important to modify the present biosphere models or to develop alternative biosphere models applying the biosphere models according to quality and quantify of the information acquired through the siting process for constructing the repository. In this study, alternative biosphere models were developed taking geosphere-biosphere interface of marine environment into account. Moreover, the flux to dose conversion factors calculated by these alternative biosphere models was compared with those by the present basic ...

Science.gov (United States)

Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

International Nuclear Information System (INIS)

In order to study the two-phase natural circulation and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed. Based on the two-phase flow scaling criteria developed under this program, an adiabatic hot leg U-bend simulation loop using nitrogen gas and water and a Freon 113 boiling and condensation loop were built. The nitrogen-water system has been used to isolate key hydrodynamic phenomena from heat transfer problems, whereas the Freon loop has been used to study the effect of phase changes and fluid properties. Various tests were carried out to establish the basic mechanism of the flow termination and reestablishment as well as to obtain essential information on scale effects of parameters such as the loop frictional resistance, thermal center, U-bend curvature and inlet geometry. In addition to the above experimental study, a preliminary modeling ...

Energy Technology Data Exchange (ETDEWEB)

Epidemiologic studies suggest a weak link between occupational or residential exposure to extremely low frequency electromagnetic fields and cancer, especially tumors of the central nervous and hematopoietic systems. This report discusses these studies with reference to basic research on ELF EMF bioeffects relevant to cancer-promoting mechanisms. Many of the studies suggest a possible interaction of ELF EMF with the immune system, endocrine system, or growth-regulatory signals and morphogenic movements that involve calcium flux through cell membranes. Many bioeffects have been reported only with certain specific combinations of frequency, amplitude, and orientation of the EMF signal with respect to the geomagnetic field. The possibility of signal-specific effects raises a complication in dosimetry for both epidemiologic and experimental studies since ELF EMF effects may not be ...

International Nuclear Information System (INIS)

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

Energy Technology Data Exchange (ETDEWEB)

The object of the present study is to develop a high performance evaporator for automotive air conditioner. The experiment has been conducted on evaporative heat transfer coefficient inside a plate type heat exchanger with a sharp 180-degree turn flow. The test plates have different formed surface, cross-ribboned channel and elliptical-ribbed channel. Also experimental study has been performed to determine optimal design in elliptical-ribbed plate heat exchanger with different turn clearance. In addition to the above experiments, refrigerant behavior and surface temperature distribution in the plate heat exchanger were observed using color thermo viewer(infrared thermometer). In this experiment, working fluid was used R-12 and test conditions were as follows : (1) saturation pressure of 2,116 kg/cm{sup 2}, (2) mass fluxes of 40 to 70 kg/m{sup 2} s, (3) heat fluxes of 4,500 to 7,300 W/m{sup 2}, (4) inlet ...

Energy Technology Data Exchange (ETDEWEB)

This report provides the results of a JASON review of the technical feasibility of using the Department of Energy`s (DOE`s) Fast Flux Test Facility (FFTF) to generate tritium needed for the enduring United States nuclear weapons stockpile.

UK PubMed Central (United Kingdom)

We analyze transport through conical channels due to the difference in particle concentration on the two sides of the membrane. Because of the detailed balance, fluxes of non-interacting particles...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

In 1946, the Philippines raised claims in the South China Sea over an area already known as Spratly Islands. This claim advanced through peculiar stages, starting when Thomas Cloma allegedly discovered islands in 1946, later named as Freedomland, and maturing to some extent in 1978 by the governments claim over the so-called Kalayaan Island Group. Considered as an oceanic expansion of its frontiers, this paper reviews the basis of the claim, first over the nature of Clomas activities, and secondly over the measures the Philippine government took as a reaction of Clomas claim of discovery of an area already known in western cartography as the Spratlys. Eventually, what is the nature of the link between the 1978 Kalayaan Islands Groups official claim and 1956 Clomas private one?

Energy Technology Data Exchange (ETDEWEB)

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

British Library Electronic Table of Contents (United Kingdom)

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

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

We write a path-integral expression for the Green function of a advected scalar on a fluid flux. (author)

Science.gov (United States)

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

International Nuclear Information System (INIS)

Reported in this paper are the theoretical and experimental studies, with regard to the effects of radiation between walls, conducted for the improvement of heat transfer characteristics of the circular duct in high temperature heat exchangers that operate through the medium of non-radiating gases at around 1,000"0C. To study the fundamental performance of the heat transfer augmentation, the experiment was carried out using a double tube at temperatures up to 900"0C. The outer tube in a double tube was selectively heated so as to give a uniform heat flux selected of 6.5 x 10"3 and 4.6 x 10"4 kcal/m"2.h, while the inner tube was used as a radiating surface to impart the radiation heat transmitted from the outer tube. Selectively preheated air was caused to flow in an annular passage at an inlet temperature selected within 100"0C to 400"0C and with the Reynolds number of 2.9 x 10"3 to 3.5 x 10"4. The heat transfer ...

Energy Technology Data Exchange (ETDEWEB)

Experimental studies on the heat transfer and fluid dynamics of a high heat flux fuel rod for a very high temperature reactor (VHTR) were performed using a single channel test rig of a fuel stack test section (T{sub 1-s}) installed in a helium engineering demonstration loop (HENDEL). The fuel rod has been developed in order to enhance the turbulent heat transfer coefficient than that of the standard fuel rod obtained by the previous experiment. Two-dimensional square ribs were settled on the outer surface of the fuel rod axially to improve the heat transfer. The configuration of a square rib is 0.5 mm in width(w), 0.5 mm in height(h) and 5 mm in pitch(p): p/h=10. The experiment were carried out under the helium gas conditions of high temperature and pressure simulated the VHTR operation. For the turbulent region of Reynolds number 2,500{approx}8,000 of the VHTR core flow condition, it was found that the heat transfer coefficient of the fuel rod ...

Energy Technology Data Exchange (ETDEWEB)

Mixed convection heat transfer from longitudinal fins inside a horizontal channel has been investigated in the natural convection dominated region for a wide range of Rayleigh numbers and different fin heights and spacings. An experimental parametric study was made to investigate effects of fin spacing, fin height and magnitude of heat flux on mixed convection heat transfer from rectangular fin arrays heated from below in a horizontal channel. The optimum fin spacing to obtain maximum heat transfer has also been investigated. During the experiments constant heat flux boundary condition was realized and air was used as the working fluid. The velocity of fluid entering channel was kept nearly constant (0.02 {<=} w{sub in} {<=} 0.025 m/s) using a flow rate control valve so that Reynolds number was always about Re = 250. Experiments were conducted for modified Rayleigh numbers 3 x 10{sup 7} < Ra{sup *} ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

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

Wastenet

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

UK PubMed Central (United Kingdom)

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

Environmental Research Database

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

Energy Technology Data Exchange (ETDEWEB)

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

CERN Document Server

Recent observations of a large excess of cosmic-ray positrons at high energies have raised a lot of interest in leptonic decay modes of dark matter particles. Nevertheless, dark matter particles in the Milky Way halo could also decay hadronically, producing not only a flux of antiprotons but also a flux of antideuterons. We show that for certain choices of parameters the antideuteron flux from dark matter decay can be much larger than the purely secondary flux from spallation of cosmic rays on the interstellar medium, while the total antiproton flux remains consistent with present observations. We show that if the dark matter particle is sufficiently light, the antideuteron flux from dark matter decay could even be within the reach of planned experiments such as AMS-02 or GAPS. Furthermore, we discuss the prospects to observe the antideuteron ...

CERN Document Server

The highly irradiated transiting exoplanet, HAT-P-7b, currently provides one of the best opportunities for studying planetary emission in the optical and infrared wavelengths. We observe six near-consecutive secondary eclipses of HAT-P-7b at optical wavelengths with the EPOXI spacecraft. We place an upper limit on the relative eclipse depth of 0.055% (95% confidence). We also analyze Spitzer observations of the same target in the infrared, obtaining secondary eclipse depths of 0.098+/-0.017%, 0.159+/-0.022%, 0.245+/-0.031% and 0.225+/-0.052% in the 3.6, 4.5, 5.8 and 8.0 micron IRAC bands respectively. We combine these measurements with the recently published Kepler secondary eclipse measurement, and generate atmospheric models for the day-side of the planet that are consistent with both the optical and infrared measurements. The data are best fit by models with a temperature inversion, as expected from the high incident flux. The models predict ...

CERN Document Server

We study the expected properties of starbursts in order to provide the point of reference for interpretation of high-z galaxy surveys and of very metal-poor galaxies. We concentrate mainly on the UV characteristics such as the ionizing spectra, the UV continuum, the Ly alpha and HeII 1640 A line and two-photon continuum emission. We use evolutionary synthesis models covering metallicities from Pop III to solar and a wide range of IMFs. We also combine the synthetic SEDs with the CLOUDY photoionization code for more accurate predictions of nebular emission, and to study possible departures from case B assumed in the synthesis models. The ionizing fluxes, UV continuum properties, and predicted Ly alpha and HeII 1640 A line strengths are presented for synthesis models covering a wider range of parameter space than our earlier calculations. Strong departures from case B predictions are obtained for Ly alpha and two-photon ...

Science.gov (United States)

Summaries are presented for those research contracts which expired between December 31, 1960 and December 31, 1981. Topics covered include: factors controlling distribution of fission products in biosphere, non-destructive methods of evaluating the U/sup 235/ and Pu content of irradiated fuel elements, studies of contamination in local marine resources, tracer studies of anemia, non-destructive analysis of irradiated fuel elements using a flux integrating monitor, mechanism of proteolysis of I/sup 131/-labeled fibrinogen, radiosensitivity of spermatogonia of Drosophila melel elements by gamma scanning, uptake and loss of radioactive material by marine bacteria, factors which influence the movement of radioactive strontium from soils to plants, biological concentration of fission products in mollusks from water, decay scheme of Tl/sup 210/, calcium balance in metabolic bone disease, development of ...