Energy Technology Data Exchange (ETDEWEB)

Cryogenic distillation is the main industrial method for separating hydrogen's isotopes, because it presents the advantage of high separating factors and also the possibility of processing great quantities of gases. In the case of multicomponent mixtures the determination of transport for molecular species between the two phases is very difficult owing to the particularities of physical characteristics of each component from the mixture. The transport of molecular species is also strongly influenced by the hydrodynamics of two phases, in strong connection with the dimension of the interface between the vapor and liquid phase. The characteristics of the interface depend on the type and geometry of the separation area: plates or package. The traditional methods of analysis for exchange processes use the concept 'theoretic plate', a physical entity for which ...

International Nuclear Information System (INIS)

Single-crystalline PbTe nanowires were synthesized using the chemical vapor transport method. They consisted of rock-salt structure PbTe nanocrystals uniformly grown in the [100] direction. We fabricated field-effect transistors using a single PbTe nanowire, providing evidence for its intrinsic n-type semiconductor characteristics. The values of the carrier mobility and concentration were estimated to be 0.83 cm"2 V"-"1 s"-"1 and 8.8 x 10"1"7 cm"-"3, respectively. The Seebeck coefficients (-72 ?V K"-"1) of individual nanowires were measured to show their n-type carrier-dominated thermoelectric transport properties.

Energy Technology Data Exchange (ETDEWEB)

Water vapor is well known to be a critical component in many aspects of atmospheric research, such as radiative transfer and cloud and aerosol processes. This requires both improved measurements of the columnar water vapor and its profiles in the atmosphere in a wide range of conditions, and adjustment of water vapor parameterizations in radiation codes including the perfection of spectroscopic parameters. In this paper we will present the results of comparison of our calculations and downward solar fluxes measured with Rotating Shadowband Spectroradiometer under conditions of horizontally homogeneous clouds. We also will discuss the sensitivity of atmospheric radiation characteristics to variations of water vapor in the band 940 nm: these results may be useful for development of new methods of retrieval of the total column water vapor content (WVC) in the ...

Energy Technology Data Exchange (ETDEWEB)

Film boiling is the mode if boiling during which the hot surface is separated from the vaporizing liquid by a nearly continuous film vapor. Film boiling is usually considered a very undesirable boiling regime since it is a relatively quiet and inefficient mode of heat transfer, particularly as compared to nucleate boiling. It is customary to analyze the two-phase flow regime of laminar flow film boiling by assuming the two-phase flow regime of laminar flow film boiling by assuming an idealized vapor film flow characterized by a smooth liquid-vapor interface. However, during stable flow film boiling, the wavy nature of the liquid-vapor interface and its role in local heat and mass transport have been largely ignored. The vapor interface is rarely stationary. Interfacial waves may substantially augment the heat transfer rates throughout the ...

International Nuclear Information System (INIS)

Natural convection of vaporizing Deuterium at 25 K transports the heat generated in the moderator cell of the cold neutron source to a He cooled condenser. The thermohydraulics of this thermosiphon were precalculated and the results verified by experiments in a 1:1 model using D_2 as fluid. The experimental results show that the thermosiphon operates stable. The demanded liquid content of the cell as well as wall temperatures below 50 K can be ensured by a proper design of the cell outlet flow geometry. A 7 min. loss of cryogenic power results in transient temperatures of the cell wall of not more than 300 K.

Energy Technology Data Exchange (ETDEWEB)

Molar enthalpies of sublimation of 1,2,4-, 1,2,3-, and 1,3,5-tri-hydroxy-benzene, were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The molar enthalpies of fusion and molar heat capacities of these compounds were measured by DSC. The measured data sets of vaporization, sublimation and fusion enthalpies were checked for internal consistency. Strength of the inter- and intra-molecular hydrogen bonding in di- and tri-hydroxy-benzenes have been assessed.

Energy Technology Data Exchange (ETDEWEB)

Data which have been collected by Los Alamos National Laboratory waste management for the hydrologic characterization of the subsurface at the low level radioactive waste disposal facility, Area G, are reported and discussed briefly. The data includes Unsaturated Flow Apparatus measurements of the unsaturated conductivity in samples from borehole G-5. Analysis compares these values to the predictions from van Genuchten estimates, and the implications for transport and data matching are discussed, especially at the location of the Vapor Phase Notch (VPN). There, evaporation drives a significant vapor flux and the liquid flux cannot be measured accurately by the UFA device. Data also include hydrologic characterization of samples from borehole G-5, Area G surface soils, Los Alamos (Cerros de Rio) basalt, Tsankawi and Cerro-Toledo layers, the Vapor Phase Notch (VPN), and additional new samples from the ...

British Library Electronic Table of Contents (United Kingdom)

This paper explores the through-/in-plane characteristics of water transport in the cathode gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC). Theoretical analysis is performed on the non-isothermal two-phase flow under flow channels. A dimensionless group Da (Damkohler number for PEFC operation), defined as the ratio of water generation rate to water vapor-phase removal rate, is formulated to characterize the flow regimes in a PEFC. This group, lumping geometrical parameters and physical properties, compares the water vapor-phase removal capability (via water diffusion and holding capacity) with the rate of water production by the oxygen reduction reaction. We find that this dimensionless group can be used to characterize the non-isothermal, two-phase phenomena: when Da&...

Energy Technology Data Exchange (ETDEWEB)

Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind`s interactions with a building`s superstructure and the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon ...

Energy Technology Data Exchange (ETDEWEB)

The excellent high temperature strength and thermal conductivity of molybdenum-base alloys provide attractive features for components in advanced magnetic and inertial fusion devices. Refractory metal alloys react readily with oxygen and other gases. Oxidized molybdenum in turn is susceptible to losses from volatile molybdenum trioxide species, MoO{sub 3}(m), in air and the hydroxide, MoO{sub 2}(OH){sub 2}, formed from water vapor. Transport of radioactivity by the volatilization, migration, and re-deposition of these volatile species during a potential accident involving a loss of vacuum or inert environment represents a safety issue. In this report the authors present experimental results on the oxidation, volatilization and re-deposition of molybdenum from TZM in flowing air between 400 and 800 C. These results are compared with calculations obtained from a vaporization mass transfer model using chemical thermodynamic ...

UK PubMed Central (United Kingdom)

1. The short duration cerebrovascular perfusion method for measuring permeability of the blood-brain barrier has been adapted to measuring transport into the retina. 2. The method has been characterized...Full Text Available

Science.gov (United States)

Using the infrared spectroscopy method, we have studied the effect of thermal dehydration (under vacuum and in air) and treatment with water vapor on the acid centers of very high silicon zeolites of the ZSM type. We have shown that dehydration under vacuum and in air completely and irreversibly removes the OH groups at 1120/sup 0/K, while treatment with water vapor removes these groups at 770/sup 0/K. The Lewis acid centers of dehydrated zeolites (represented by two types of centers) are more heat-stable than the Bronsted acid centers, but the vapor treatment at 1020/sup 0/K leads to the disappearance of the Lewis acid centers. In this work, we discuss the reasons for destruction of the acid centers of the zeolites under different treatment conditions.

Energy Technology Data Exchange (ETDEWEB)

A versatile method for estimating the characteristics of radon transport in soil is developed. The method allows the following characteristics to be estimated: depth distribution function of the soil gas radon concentration, equilibrium radon concentration in the soil air, depth at which the radon concentration reaches its equilibrium value, radon flux density from the Earth's surface, and convective radon transport velocity. The method is based on soil gas radon concentration measurements and is appropriate in the case of relatively uniform geology. (orig.)

Science.gov (United States)

In drug development, Caco-2 cells are often employed to study the influence of membrane transporters on drug permeability. The aim of the current study was to characterize permeability and kinetic parameters of selected organic anionic compounds in Caco-2 cells, and to investigate whether the Caco-2 cell line may be used as an overall model to predict interactions on multiple membrane transporters in the intestine. Taurocholic acid (TCA) and estrone-3-sulfate (E(1) S) were used as model substrates. Possible inhibitors studied were TCA, E(1) S, taurolithocholic acid, fluvastatin, and glipizide. The effects of these compounds on initial uptake, apparent permeability, and intracellular end-point accumulations of the probe substrates were studied. Both interactions on apical and basolateral influx transporters were observed. These interactions were proposed to be mediated mainly by the apical sodium-dependent bile acid ...

Energy Technology Data Exchange (ETDEWEB)

Microfluidic systems and methods are disclosed which are adapted to transport and lyse cellular components of a test sample for analysis. The disclosed microfluidic systems and methods, which employ an electric field to rupture the cell membrane, cause unusually rapid lysis, thereby minimizing continued cellular activity and resulting in greater accuracy of analysis of cell processes.

Energy Technology Data Exchange (ETDEWEB)

This paper examines the feasibility of returning coal mine wastes to the mined-out areas, as encouraged by PL 95-87, the ''Surface Mining Control and Reclamation Act of 1977'' (SMCRA). Reviews a National Academy of Sciences report which identified alternative backfilling methods. Presents diagram of mechanical backfilling with gravity and mechanical transport, and tables of existing underground mine waste disposal methods and a summary of technical feasibility of alternative disposal systems. Evaluated systems include gravity disposal with mechanical surface transport; gravity disposal with mechanical in-mine transport; complete mechanical disposal; mechanical disposal with gravity surface to underground transport; direct hydraulic disposal; hydraulic disposal with natural head; hydraulic disposal with artificial head; ...

Energy Technology Data Exchange (ETDEWEB)

The failure of receivers has been one of the main operating problems at the White Cliffs solar thermal power plant. This Technical Note reports the results of an initial investigation that identifies the cause as having been their thermal fatiguing of the tube walls. The fatigue appears to be caused by unstable heat transfer at vapor qualities below the point where critical heat flux is generally exceeded. Methods for avoiding this problem are tested.

Energy Technology Data Exchange (ETDEWEB)

We present a numerical method for computing diffusive transport on a surface derived from image data. Our underlying discretization method uses a Cartesian grid embedded boundary method for computing the volume transport in region consisting of all points a small distance from the surface. We obtain a representation of this region from image data using a front propagation computation based on level set methods for solving the Hamilton-Jacobi and eikonal equations. We demonstrate that the method is second-order accurate in space and time, and is capable of computing solutions on complex surface geometries obtained from image data of cells.

Energy Technology Data Exchange (ETDEWEB)

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

British Library Electronic Table of Contents (United Kingdom)

A new numerical technique called the convolution-based particle tracking (CBPT) method is developed to simulate resident or flux-averaged solute concentrations in groundwater models. The method is valid for steady-state flow and linear transport processes such as sorption with a linear sorption isotherm and first-order decay. The CBPT method uses particle tracking to take advantage of the ability of particle-based approaches to maintain sharp fronts for advection-dominated transport problems common in groundwater modeling and because of the flexibility of the random walk method to simulate a wide range of possible forms of the dispersion tensor. Furthermore, the algorithm for carrying out the convolution and superposition calculation from particle tracking results is very efficient. We sho...

British Library Electronic Table of Contents (United Kingdom)

Methods of X-ray diffraction and transmission electron microscopy were used to study the microstructure of dispersion-strengthened Cu-Al2O3 nanocomposites obtained by the method of simultaneous deposition of Cu and Al2O3 from the vapor phase. The effect of the size of particles of the oxide (Al2O3) and of their content on the electrical resistance of the composite has been considered. The results obtained make it possible to suppose that the main structural factor that determines the electrical resistance of the composite are nanodispersed particles of Al2O3 with a size of less than 20 nm.

International Nuclear Information System (INIS)

A method is proposed for the quantitative isolation of radiothallium in gas form from proton-bombarded lead of mass up to 20 g. The molten lead is kept at about 800 K in hydrofluoric-acid vapor (HF/H_2O #approx =# 1) at a reduced pressure (#<=#4 Pa). We used 99.9% lead with the U-240 cyclotron at the Nuclear Research Institute, Academy of Sciences of the Ukrainian SSR, or the phasotron at the Join Nuclear Research Institute, which gave protons at 65 and 680 MeV correspondingly.

Energy Technology Data Exchange (ETDEWEB)

Most plans for the disposition of surplus nuclear materials involve storage in sealed containers where the evolution of gases from reactions of adsorbed water could present both pressure and flammability hazards[l] . Despite efforts such as calcining the material to minimize the water content prior to packaging, both residual moisture and readsorbed water may be present in the final containers . Given the anticipated temperature excursions during transportation and storage, this water may thermally desorb, increasing the pressure, and/or thermally dissociate to produce H2 gas, increasing flammability hazards . In addition, the radiation from the nuclear material may induce radiolysis of the water with the likely products being water vapor, H2, 02 and H2O2. In order to better understand the relative importance of the thermal- and radiationinduced chemistry, we have studied the interactions of water on single crystals of uranium dioxide .

British Library Electronic Table of Contents (United Kingdom)

The utilization of thermal fluctuations or Johnson/Nyquist noise as a spectroscopic method to determine transport properties in conductors or semiconductors is developed. The autocorrelation function is obtained from power spectral density measurements thus enabling electronic transport property calculation through the Green-Kubo formalism. This experimental approach is distinct from traditional numerical methods such as molecular dynamics simulations, which have been used to extract the autocorrelation function and directly related physics only. This work reports multi-transport property measurements consisting of the electronic relaxation time, resistivity, mobility, diffusion coefficient, electronic contribution to thermal conductivity and Lorenz number from experimental data. Double va...

Energy Technology Data Exchange (ETDEWEB)

A novel two-phase flow management process useful for active thermal power rejection in space is introduced. The process serves as a condenser in a Rankine cycle and is applicable for thermal energy management needs in low gravity environments. Benefit is derived from the ability to utilize the high specific energy transport capability of two-phase flow, while not requiring mass-intensive solutions nor complex control strategies to maintain design energy balance integrity. Initial design calculations for a hypothetical space vapor cycle demonstration experiment were done and a steady-state computer model of the novel condensing process was created and used to evaluate its potential to maintain the design energy balance of the experiment. The experiment (approximately 28 kg) was a supercritical organic thermal loop operating between 500 and 400 Kelvin at a mass flow of 1 grain per second; using R-113 as the working fluid and rejecting all of its ...

International Nuclear Information System (INIS)

The characteristics of per-fluorocarbon compounds (PFC) are colorless, non-toxic, easily vaporized and nonflammable. Also, some of them are liquids of a high density, low surface tension, low latent heat and low specific heat. These particular chemical and physical properties of fluoro-organic compounds permit their use in very different fields such as electronics, medicine, tribology, nuclear and material science. The Sonatol process was developed under a contract with the DOE. The Sonatol process uses an ultrasonic agitation in a PFC solution that contains a fluorinated surfactant to remove radioactive particles from surfaces. Filtering the suspended particles allows the solutions to be reused indefinitely. They applied the Sonatol process to the decontamination of a heterogeneous legacy Pu-238 waste that exhibited an excessive hydrogen gas generation, which prevents a transportation of such a waste to a Waste Isolation Pilot Plant. Korea ...

Energy Technology Data Exchange (ETDEWEB)

In this work we present an ultra-low temperature method for the oxidation of an amorphous silicon-carbide-nitride (SiCN) material. The SiCN is deposited on silicon substrates by plasma enhanced chemical vapor deposition using CH{sub 4}, SiH{sub 4}, and N{sub 2} chemistry. The physical and chemical properties are characterized for the as-deposited SiCN and post-oxidized films are discussed. The SiCN film is exposed to oxygen plasma, where it undergoes a chemical transformation into a binary SiO{sub 2} material system. A 1.7 nm/min oxidation rate is typical for this process and compares favorably to oxidation methods utilizing much higher temperatures. The substrate temperature remains extremely low throughout the oxidation process, T{sub s} < 200 deg. C. Changes in film stress, optical constants, film thickness, surface roughness, and film density are measured. Chemical analysis by X-ray photoelectron spectroscopy is ...

International Nuclear Information System (INIS)

We solve an R -linear problem for a multiple-connected circular domain in a class of doubly periodic functions in analytic form by a method of functional equations. This problem models transport properties of two-dimensional composite materials made from a collection of disks embedded in an otherwise uniform host.

Energy Technology Data Exchange (ETDEWEB)

This project (a) demonstrated specific dopamine transporter (DAT) uptake in vivo and metabolic stability of a radiolabelled cycloplentadieny rhenium compound in rats and baboons, (b) showed that cyclopentadieny tricarbonyl rhenium and technetium compounds conjugated tropanel could be made by metal transfer with ferrocenes; and (c) explored new methods of synthesizing these compounds under mild conditions.

Energy Technology Data Exchange (ETDEWEB)

A new nonlinear S{sub n} transport differencing scheme for slab geometry is presented that is fourth order accurate for small meshes and is strictly positive. The new scheme has been coded into the existing ONELD code and tested. Numerical results to demonstrate the accuracy and positivity of this new scheme are presented.

Energy Technology Data Exchange (ETDEWEB)

Methods and apparatus for detecting the presence of explosives by analyzing a vapor sample from the suspect vicinity utilize at least one microcantilever. Explosive gas molecules which have been adsorbed onto the microcantilever are subsequently heated to cause combustion. Heat, along with momentum transfer from combustion, causes bending and a transient resonance response of the microcantilever which may be detected by a laser diode which is focused on the microcantilever and a photodetector which detects deflection of the reflected laser beam caused by heat-induced deflection and resonance response of the microcantilever. 2 figs.

Energy Technology Data Exchange (ETDEWEB)

Ion neoclassical transport with finite orbit width dynamics is calculated over whole poloidal cross section by using accurate {delta}f method which employs an improved like-particle collision operator and an accurate weighting scheme to solve drift kinetic equation. Ion thermal transport near magnetic axis shows a great reduction from its conventional neoclassical level due to non-standard orbit topology, like that of previous {delta}f simulation. On other hand, the direct particle loss from confinement region may strongly increase ion energy transport near the edge. It is found that ion parallel flow near the axis is also largely reduced due to non-standard orbit topology. In the presence of steep density gradient, ion thermal conductivity is significantly reduced, and an ion particle flux is driven by self-collision alone. (author)

Science.gov (United States)

Technologies for materials, processes, and manufacturing that will provide safe, .... advanced energy conversion techniques, and pulsed inductive and ... duration antimatter storage and transportation, and methods for utilizing ...... EVA systems can be found in the EVA Technology Roadmap of the EVA Project Plan. ...

Science.gov (United States)

... by Remote Setting., Maryland Sea Grant Extension Program. Oyster aquaculture workbook series. Publication UM-SG-MAP-95-03. ... ...

International Nuclear Information System (INIS)

A method for the analysis of three-component mixtures is described. The method is used for contact-free determination of component concentration in the mixtures transported via a product duct. Formulae as an aid in choosing the gamma radiation source and estimating the efficiency of measurement are given. The errors of measurement by the method of formaline-water-carbamide mixture is 1-2 %. 9 refs.; 1 fig.

International Nuclear Information System (INIS)

Real-time neutron radiography has been used to study the dynamic behavior of two-phase flow and measure the time averaged vapor fraction in a heated metal tube containing boiling steam-water operating at up to 15 bar pressure. The neutron radiographic technique is non-intrusive and requires no special transparent window region. This is the first time this technique has been used in an electrically heated pressurized flow loop. This unique experimental method offers the opportunity to observe and record on videotape, flow patterns and transient behavior of two-phase flow inside opaque containers without disturbing the environment. In this study the test sections consisted of stainless steel tubes with a 1.27 cm outer diameter and wall thicknesses of 0.084 and 0.124 cm. The experiments were carried out at the Pennsylvania State University 1 MW TRIGA reactor facility utilizing a Precise Optics neutron radiography camera. The inlet water ...

Science.gov (United States)

In this paper, we studied vapor-liquid equilibria (VLE) and adsorption of ethylene on graphitized thermal carbon black and in slit pores whose walls are composed of graphene layers. Simple models of a one-center Lennard-Jones (LJ) potential and a two-center united atom (UA)-LJ potential are investigated to study the impact of the choice of potential models in the description of VLE and adsorption behavior. Here, we used a Monte Carlo simulation method with grand canonical Monte Carlo (GCMC) and Gibbs ensemble Monte Carlo ensembles. The one-center potential model cannot describe adequately the VLE over the practical range of temperature from the triple point to the critical point. On the other hand, the two-center potential model (Wick et al. J. Phys. Chem. B 2000, 104, 8008-8016) performs well in the description of VLE (saturated vapor and liquid densities and vapor pressure) over the wide range of ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

In the region of annular liquid film-mist flow, the behavior of the droplets formed from the liquid film and the rate of formation are the subjects to be clarified in connection with the forecast of dry-out point, which becomes a problem in the region of high dryness such as reactor cooling system and steam generators. Many researches have been performed on such problem in vertical tubes, but the characteristics in horizontal flow have not yet been sufficiently clarified. This series of research is to clarify various characteristics, such as the velocity of vapor phase, the flow rate distribution of droplets, the formation and adhesion of droplets and the structure of liquid film, in the region of liquid film-mist flow, where liquid film exists on the bottom of a horizontal rectangular channel, and vapor flow is accompanied by droplets. In this study, by the measurement of the flow rate distribution of droplets on respective cross sections ...

International Nuclear Information System (INIS)

Use of high plutonia MOX as fuel is contemplated from the point of view of rapid disposition of plutonium and economic power generation. The fuel pellets are subjected to steep thermal gradients #approx# 1700 K drop across a radius of #approx# 2.5mm. This leads to evaporation-condensation of the fuel constituents to cooler regions. Vaporization depends on fuel compositions such as Pu fraction, Oxygen-to-Metal (O/M) ratio and local temperature. Knowledge of vapour chemistry is essential in understanding the fuel behavior. The vaporization behaviour of MOX was analyzed in this work using thermochemical methods. The vapour phase consisted of nine species; O, O_2, Pu, PuO, PuO_2, U, UO, UO_2 and UO_3. Oxygen formed part of the vapour phase along with other species and oxygen potential was not controlled independently. The vapour pressures were estimated at 2000 K as a function of (O/M) for several Pu-fraction. Results for ...

Science.gov (United States)

MINC stands for Multiple INteracting continua.'' It is an approximate method for modeling fluid and heat flow in fractured- porous media, developed by Pruess and Narasimhan (1982, 1985) at the Lawrence Berkeley Laboratory. The method is applicable to flow processes in which an important aspect is the exchange of fluid, heat, or chemical species between fractures and unfractured rock. Examples include production and injection operations in fractured geothermal reservoirs, water-flooding, steamflooding, and other methods for enhanced oil recovery from fractured reservoirs, as well as chemical transport and contaminant migration in fractured rock. MINC can only be applied to media in which the fractures are sufficiently well connected so that a continuum treatment of flow in the fracture network can be made.

International Nuclear Information System (INIS)

The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ? ?p at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ? ?p, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.

British Library Electronic Table of Contents (United Kingdom)

Classical methods for the study of complex fluid phase behavior include static and dynamic equilibrium cells that usually require vapor and liquid recirculation. These are sophisticated, costly apparatus that require highly trained operators, usually months of labor-intensive work per mixture, and the data analysis is also rather complex. Simpler approaches to the fundamental study of azeotropes are highly desirable, even if they provide only selected cuts through the phase diagram. Recently, we introduced an advanced distillation curve measurement method featuring: (1) a composition explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation o...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to present a summary of new methods, employing Lie algebraic tools, for characterizing beam dynamics in charged-particle optical systems. These methods are applicable to accelerator design, charged-particle beam transport, electron microscopes, and also light optics. The new methods represent the action of each separate element of a compound optical system, including all departures from paraxial optics, by a certain operator. The operators for the various elements can then be concatenated, following well-defined rules, to obtain a resultant operator that characterizes the entire system. This paper deals mostly with accelerator design and charged-particle beam transport. The application of Lie algebraic methods to light optics and electron microscopes is described elsewhere (1, see also 44). To keep its scope within reasonable bounds, ...

International Nuclear Information System (INIS)

Etching of SiO_2 rods has been obtained with a dc torch with argon as the process gas in an air environment at atmospheric pressure; the high temperature of the plasma jet causes vaporization of the exposed area. The apparatus and torch operative parameters have been set up to obtain a depth etch rate of up to 0.6 mm min"-"1 corresponding to 0.826 g min"-"1. An enthalpy probe has been employed to monitor the plasma conditions before the thermal plasma etching process and from the experimental etch rate a surface rod temperature of T_s_u_r = 2057 K has been derived. Etching has been obtained with uniformity over the entire exposed area with peak to peak differences below 1%. The plasma to rod heat transfer has been simulated using a commercial CFD code Fluent (copyright). The model consists of a non-steady two-dimensional simulation for a compressible turbulent fluid, with an adapted grid calculation. Boundary conditions have been set out using the enthalpy probe ...

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the analysis of dominant loss mechanisms in direct methanol fuel cells (DMFC) and hydrogen fed polymer electrolyte membrane fuel cells (PEFC) by means of experimental characterization and modeling work. Due to different fuels used in these two fuel cell types, the dominant loss mechanisms are different in their nature. All in-situ characterization techniques that are used in this work are based on a novel test fuel cell with embedded reference electrodes. The first part of this work presents a new concept for realizing a reference electrode configuration in a polymer electrolyte membrane fuel cell by means of laser ablation. The laser beam is used to evaporate a small gap into the electrode surface of a catalyst coated membrane (CCM) to isolate the reference electrode from the working/counter electrode (WE/CE). This method enables the simultaneous ablation of the electrodes on both sides of the CCM because the membrane is transparent for the ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) is a 400-MWt, sodium-cooled reactor located on the Hanford Site near Richland, Washington, USA. The FFTF is owned by the U.S. Department of Energy and is operated by the Westinghouse Hanford Company. The FFTF was designed to test fuels and materials for use in liquid metal reactors. Since initial operation in 1982, anticipated breaches of experimental fuel pins have released fission products, including cesium, into the primary sodium. Because of its high volatility, cesium vaporizes into the cover gas space, where it condenses on components and equipment and is transported into the cover gas outlet. Because of the long half-life of "1"3"7Cs, these deposits result in long-term, local radiation levels that make contact maintenance difficult. Thus, a cesium trap was installed in FFTF to reduce the cesium level in the sodium. The trap could also permit a Run Beyond Cladding Breach (RBCB) program without ...

Energy Technology Data Exchange (ETDEWEB)

This report is composed of the following two parts and appendix. (I) Improvement of the Method for Evaluating Reactivity Based on Monte Carlo Perturbation Theory: Theoretical formulation in Monte Carlo perturbation method had been checked, and then introduced into a calculation code. There are some cases that the results of the change of eigenvalues becomes positive or negative by changing the estimator, and there is no reasonable difference in the results between the conventional method, which does not consider the change of neutron source distribution caused by a perturbation, and the new method, which consider that change. Thus it is still necessary to check the Monte Carlo perturbation code. (II) Improvement of Nodal Transport Method for 3-D Hexagonal Geometry: We can accurately evaluate hexagonal geometry FBR core by nodal transport ...

Energy Technology Data Exchange (ETDEWEB)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

The shortage of fresh water is increasing at alarming levels, even in temperate zones. Desalination of brackish and seawater is being considered as a solution to growing water demands. Seawater desalination can be accomplished through reverse osmosis, vapor compression, vapor absorption and thermally driven systems. The most suitable process for large-scale desalination plants is successive brine evaporation-condensation with intermediate heat recovery. However, higher process efficiency could be achieved. The use of low temperature heat sources in seawater desalination requires an efficient method of evaporation and condensation at relatively low vapor pressures. This could be achieved in a humidification-dehumidification process using circulated air to enhance evaporation of water. Simulation models, however, neglect either the heat of evaporation or the changes in air and water properties within ...

Energy Technology Data Exchange (ETDEWEB)

An analysis of the current state of track-laying operations in open-cut mines is given and their labor intensive nature is noted. The lag in the technological development of mechanization equipment for track laying and repair operations is noted. Results are given from developments by the Scientific Research Institute of Open-Pit Mining Operations in the field of mobile transportation technology and promising modular route design. Also examined are the problems of improving the routing bases in the industry. The absence of factories for manufacturing transportation technology and equipment is reflected most evidently in the technical and cost characteristics of coal production by an open-cut method and requires immediate solution.

Energy Technology Data Exchange (ETDEWEB)

A method of augmenting heat transfer in the interior of a fluid or from the interface of a solid in contact to a fluid by utilizing electro hydrodynamic (EHD) phenomena has the following advantages: the heat transfer can be effected by using a relatively small, light-weight high voltage source and some simple structural members; no vibration and noise are generated; the method has a control function to control heat transfer by adjustment of field and voltage; and this method is effective in cost-saving. It is mass transfer by the electric force caused by interaction between true charges or polarized charges in a fluid and external electric filed that plays an important role in most of such heat transfer augmentation methods by EHD. Examples of heat transfer augmentation by EHD phenomena include electricaly induced convection, contribution of EHD effect to heat transfer accompanied with boiling, heat ...

Science.gov (United States)

Homogenous Al{sub x}Ga{sub 1{minus}x}P liquid phase epitaxial layers have been obtained with the temperature difference method under controlled vapor pressure (TDM-CVP). Very clear fine structures near band edge in photoluminescence spectra have been observed at 77 K for the first time. Photoluminescence measurement results confirmed that the free exciton recombination without phonon assistance plays an important role in the luminescence at 77 K and becomes dominant at room temperature. It is considered that Zero-phonon assisted free exciton recombination is intensified by some local perturbations to electrical potentials against carriers or excitons introduced by Al atoms in Al{sub x}Ga{sub 1{minus}x}P layers, which can give momentum change necessary for recombination.

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The low-power operation of a semiconductor buried-heterostructure Raman laser is reported. We are developing these devices for very wide-band optical communication in the terahertz frequency region. It has a structure with a GaP active layer and Al{sub {ital x}}Ga{sub 1{minus}{ital x}}P cladding layers, which are grown by the temperature-difference method under controlled vapor pressure. By making the stripe width 30--40 {mu}m, we have obtained a threshold pump power of 500 mW. A low-threshold semiconductor Raman laser can be pumped by semiconductor injection lasers. We have measured the optical loss of the waveguide and detected the contribution from scattering and leakage at heterointerfaces.

International Nuclear Information System (INIS)

The general development of variational methods for fusion reactor blanket studies is given. Important quantities such as tritium breeding ratio and total nuclear heating are linear functionals of the solutions to the Boltzmann transport equation. To estimate a neutronic quantity by variational methods is, in general, to carry out the scalar product formulation of the Roussopoulos variational principle, or the Schwinger variational principle, with the help of the associated adjoint transport equation where the appropriate response function for the estimate is taken as the source. A multipoint interpolation method based on the above variational principles has been developed and compared to other variational approaches. The method of variational interpolation removes the need to compute both forward and adjoint solutions while the error has the characteristic of ...

International Nuclear Information System (INIS)

An integrated beam optics-nuclear processes framework is essential for accurate simulation of fragment separator beam dynamics. The code COSY INFINITY provides powerful differential algebraic methods for modeling and beam dynamics simulations in absence of beam-material interactions. However, these interactions are key for accurately simulating the dynamics of heavy ion fragmentation and fission. We have developed an extended version of the code that includes these interactions, and a set of new tools that allow efficient and accurate particle transport: by transfer map in vacuum and by Monte Carlo methods in materials. The new framework is presented, along with several examples from a preliminary layout of a fragment separator for a facility for rare isotope beams.

Science.gov (United States)

PMID:10111634

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The design of the first structural wall (FSW) in an inertial confinement fusion (ICF) reactor requires some knowledge of the expected wall loading produced by x-ray and neutron deposition; specifically in the High Yield Lithium Injection Fusion Energy (HYLIFE) reactor, wall loading results from two sources -- gas shock and liquid impact. Gas shock is derived from x-ray deposition in the thin layers of exposed blanket material, producing ionized vapor, which will generate gas shock on the FSW. Liquid impact, on the other hand, results from the acceleration of liquid blanket material by two possible forces -- the drag from vapor expansion through the blanket material and the neutron-induced isochoric disassembly process. Both impacts, however, are coupled by the interaction of hot gas expanding through the liquid blanket. This paper discusses scaling methods for estimating pressure and impulse on the HYLIFE FSW from these ...

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The authors apply the nonlinear WENO (Weighted Essentially Nonoscillatory) scheme to the spatial discretization of the Boltzmann Transport Equation modeling linear particle transport. The method is a finite volume scheme which ensures not only conservation, but also provides for a more natural handling of boundary conditions, material properties and source terms, as well as an easier parallel implementation and post processing. It is nonlinear in the sense that the stencil depends on the solution at each time step or iteration level. By biasing the gradient calculation towards the stencil with smaller derivatives, the scheme eliminates the Gibb's phenomenon with oscillations of size O(1) and reduces them to O(h{sup r}), where h is the mesh size and r is the order of accuracy. The current implementation is three-dimensional, generalized for unequally spaced meshes, fully parallelized, and up to fifth order accurate ...

Science.gov (United States)

Observational evidence is presented for the nucleation of condensation nuclei (CN) in the clear air adjacent to an isolated, marine, cumulus cloud. Two separate regions of particle nucleation are identified: one located above the cloud top, and the second located downwind of the cloud near the level of the anvil outflow. The regions of high CN concentrations were located in extremely clean marine air, with unactivated aerosol surface area (excluding the nucleation mode) less than 2 sq micrometers/cu cm, air temperature -31 C, and higher relative humidities than the undisturbed environment. Vertical profile measurements downwind of the cloud showed that CN concentrations at the level of the anvil outflow (4.9 km) were 8 times greater than at any other level between the surface and 5.3 km. A conceptual model is formulated in which aerosol particles, sulfur dioxide (SO2), sulfuric acid vapor (H2SO4), dimethyl sulfide (DMS), and ozone (O3) from the boundary layer are ...

International Nuclear Information System (INIS)

Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.

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The four mines supplying the Sasol-2 plant at Secunda, South Africa are approaching their full production potential of 29 million t/year. Current production is 27.7 million t/year of coal for gasification and steam raising. Three mining methods are employed: bord and pillar, longwall and continuous mining. Details are given of the mining operations and machinery. A 43 km overland conveyor transports the coal to the Sasol plant stockpile.

International Nuclear Information System (INIS)

Decision-making is strongly based on modelling in two of our water supply projects concerning artificial ground water. The model used is a 2-dimensional flow and transport model using the element method. Due to sharp variations in Finnish soils, the modelling process is based on careful and detailed evaluation of basic hydrogeological data before and during model calibration.

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Contents of this report are under the following topical sections: Legal Authority; Summary and Scope; Data Collection Activities; Industry Description; Industry Subcategorization; Water Use and Wastewater Characterization; Pollutants Selected for Regulation; Pollution Prevention and Wastewater Treatment Technologies; Development of Control and Treatment Options; Costs of Technology Bases for Regulations; Pollutant Reduction Estimates; Non-Water Quality Impacts; Implementation of Proposed Effluent Limitation Guidelines and Standards; Analytical Methods; and Glossary.

International Nuclear Information System (INIS)

A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.

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The history of explosives vapor detection includes almost every detection strategy known to man. Initial attempts to utilize these techniques were dismal failures. However, with the development of the Electron Capture Detector (ECD), the first promising detection of explosives vapors became possible. The present commercial explosives detectors detect the higher vapor pressure materials but not the whole spectrum. This paper describes the basic properties of explosives molecules and our research to utilize these properties for increased detection sensitivity.

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The possibility of obtaining high yields of hydrogen through the exposure of calcium hydroxide to natural uranium fission fragments is confirmed experimentally. The amounts of hydrogen obtained in some experiments were determined not only from the mass-spectrometry data, but also with the use of standard chemical analysis methods. The radiolytic hydrogen yield averaged over six independent experiments comprises 20.41 hydrogen molecules per 100 eV of absorbed fission fragment energy. The corresponding energy efficiency makes up to 60.62. Since on interaction with water or water vapor calcium hydroxide enters into the exothermal reaction to liberate 15.6 kcal/mole, it can easily be regenerated; this was attested to by one of irradiation experiments. Therefore, in the long run, we are dealing with a radiolytic decomposition of water at low temperatures or at temperatures readily available with modern reactor engineering techniques. Comparison of ...

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The metal dependence of mesoporous activated carbons with various metal acetylacetonate (acac) particles prepared from Morwell coal was studied. In experiment, the mixture of Morwell coal and acac metal complexes were dissipated into tetrahydrofuran, and after agitation in Ar atmosphere, the solvent was removed by vacuum distillation. Coal specimens with Fe(acac)3, Ni(acac)2 and Co(acac)2 as acac complexes were activated by exchanging flow gas with water vapor after heat treatment in N2 gas flow at 900{degree}C. The pore sizes of the specimens were obtained from N2 adsorption isotherms by BET method and BJH method. Conditions of pores and metals in the specimens were examined by XRD measurement and TEM observation. The relation between the above conditions and pore characteristics obtained from adsorption experiment was also examined. As a result, the difference in mesopore ratio between the specimens and blank specimens ...

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Cu/YSZ cermet (40 and 60 vol.% Cu powder with balance YSZ) is a more economical cathode material than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of Cu and YSZ powders, pressing into pellets (o 13 mm x 2 mm) and subsequent sintering process at 700 deg. C under flowing 5%-H{sub 2}/Ar gas. The Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as XRD, SEM, and laser diffraction and scattering method. Electrical conductivity of sintered Cu/YSZ cermet pellets thus fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermets. The effect of composite composition on the electrical conductivity was investigated and a marked increase in electrical conductivity for copper contents greater than 40 vol.% in the composite was explained by percolation threshold. ...

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

British Library Electronic Table of Contents (United Kingdom)

Purpose Nonpoint sources (NPS) pollution has been an important cause for water quality impairment worldwide. To take the temporal variations of both NPS pollution and in-stream attenuation into consideration, an inverse modeling approach and the load duration curve (LDC) method were combined for variable nutrient total maximum daily load (TMDL) development. Methods Water quality and hydrological parameters were monitored monthly along the ChangLe River system in 2004?2008. The catchment NPS export load (EL) and TMDL for total nitrogen (TN) were estimated by the inverse format of an existing stream nutrient transport equation. The LDC method was used to describe the variability of EL, TMDL, requiring load (RLR) and percent (the ratio between the RLR and the EL, RPR) reduction, and then to s...

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Moisture profiles from neutron probe data provide valuable information in site characterization and to supplement ground water monitoring efforts. The neutron probe precision error (reproducibility) is found to be about 0.2 vol% under in situ field conditions where the slope in moisture content with depth is varying slowly. This error is about 2 times larger near moisture spikes (e.g., at the vapor phase notch), due to the sensitivity of the probe response to vertical position errors on the order of 0.5 inches. Calibrations were performed to correct the downhole probe response to the volumetric moisture content determined on core samples. Calibration is sensitive to borehole diameter and casing type, requiring 3 separate calibration relations for the boreholes surveyed here. Power law fits were used for calibration in this study to assure moisture content results greater than zero. Findings in the boreholes reported here confirm the broad features seen previously ...

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The conversion of highly radioactive waste liquor into glass by the pot vitrification process has been studied at Harwell using a full-scale inactive pilot plant. A summary of the off-gas behavior and its interpretation is presented. Experimental runs were carried out on 3 representative wastes (MAGNOX - thermal reactor, metal fuel, THORP - thermal oxide fuel and PFR - fast reactor oxide fuel) using 2 methods of feeding the glass-formers (slurry and crizzle). Materials were carried over from the vitrification vessel into the off-gas system by entrainment supplemented by volatilization. The overall behavior of the off-gas was consistent with the presence in it of 5 separate aerosols of particulate matter. Sources of entrainment gave rise to 3 aerosols, and a further 2 aerosols were formed as a result of chemical reaction (Ru) and condensation (Cs) processes involving the volatile species. Entrainment was enhanced when the feed contained free alkali nitrate. The Ru ...

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The Heat Cycle Research Program, which is being conducted for the Department of Energy, has as its objective the development of the technology for effecting the improved utilization of moderate temperature geothermal resources. To meet this objective, the program has as one of its goals to improve the performance of geothermal binary cycles to levels approaching the practicable thermodynamic maximum. In pursuit of this goal, tests are being conducted at the Heat Cycle Research Facility located at the DOE Geothermal Test Facility, East Mesa, California. The current testing involves the investigation of binary power cycle performance utilizing mixtures of non-adjacent hydrocarbons as the working fluids, with supercritical vaporization and in-tube condensation of the working fluid. In addition to the present test program, preparations are being made to investigate the binary cycle performance improvements which can be achieved by allowing supersaturated ...

British Library Electronic Table of Contents (United Kingdom)

A large database (507 station-years) of daily suspended particulate matter (SPM) concentration and discharge data from 36 stations on river basins ranging from 600?km2 to 600,000?km2 in size (USA and Europe) was collected to assess the effects of SPM transport regime on bias and imprecision of flux estimates when using infrequent surveys and the discharge-weighted mean concentration method. By extracting individual SPM concentrations and corresponding discharge values from the database, sampling frequencies from 12 to 200 per year were simulated using Monte Carlo techniques. The resulting estimates of yearly SPM fluxes were compared to reference fluxes derived from the complete database. For each station and given frequency, bias was measured by the median of relative errors between estima...

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The validity is given to the newly proposed two weighting {delta}f scheme (Wang et al., Research Report of National Institute for Fusion Science NIFS-588, 1999) for collisional or neoclassical transport calculations, which can solve the drift kinetic equation taking account of effects of steep plasma gradients, large radial electric field, finite banana width, and the non-standard orbit topology near the axis. The marker density functions in weight equations are successively solved by using the idea of {delta}f method and a hierarchy of equations for weight and marker density functions is obtained. These hierarchy equations are solved by choosing an appropriate source function for each marker density. Thus the validity of the two weighting {delta}f scheme is mathematically proved. (author)

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This document describes payload control at LLNL to ensure that all shipments of CH-TRU waste in the TRUPACT-II (Transuranic Package Transporter-II) meet the requirements of the TRUPACT-II SARP (safety report for packaging). This document also provides specific instructions for the selection of authorized payloads once individual payload containers are qualified for transport. The physical assembly of the qualified payload and operating procedures for the use of the TRUPACT-II, including loading and unloading operations, are described in HWM Procedure No. 204, based on the information in the TRUPACT-II SARP. The LLNL TRAMPAC, along with the TRUPACT-II operating procedures contained in HWM Procedure No. 204, meet the documentation needs for the use of the TRUPACT-II at LLNL. Table 14-1 provides a summary of the LLNL waste generation and certification procedures as they relate to TRUPACT-II payload compliance.

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This paper describes how hydrogen transport affects the severity of hydrogen embrittlement in 300 M and AerMet100 ultra high strength steels. Slow strain rate tests were carried out on specimens coated with electrodeposited cadmium and aluminium-based SermeTel 1140/962. Hydrogen diffusivities were measured using two-cell permeation and galvanostatic charging methods and values of 8.0 x 10{sup -8} and 1.0 x 10{sup -9} cm{sup 2} s{sup -1} were obtained for 300 M and AerMet100, respectively. A two-dimensional diffusion model was used to predict the hydrogen distributions in the SSR specimens at the time of failure. The superior embrittlement resistance of AerMet100 was attributed to reverted austenite forming around martensite laths during tempering.

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In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of ...

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This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidized bed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is ...

International Nuclear Information System (INIS)

Neutron radiography (NR) is a useful non-destructive method for determination of hydrogen content in various building and technical materials. Monitoring of transport processes of moisture and hydrogenous liquids in porous building materials is enabled by fast, quasi-real-time NR methods based on novel imaging plate neutron detectors (IP-NDs). Hydrogen content in the samples is determined by quantitative analysis of measured profiles of neutron attenuation in the samples. Detailed description of quantitative NR method is presented by the authors in another accompanying contribution at this conference. Deterioration of building materials is originated by different processes that all require presence of water therefore it is essential to limit or prevent the transport of water through the porous material. In this presentation, results of a study of clay brick impregnation by silicone ...

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This paper is concerned with the validation of the 3D deterministic neutral-particle transport theory code EVENT for shielding applications. The code is based on the finite element-spherical harmonics (FE-P{sub N}) method which has been extensively developed over the last decade. A general multi-group, anisotropic scattering formalism enables the code to address realistic steady state and time dependent, multi-dimensional coupled neutron/gamma radiation transport problems involving high scattering and deep penetration alike. The powerful geometrical flexibility and competitive computational effort makes the code an attractive tool for shielding applications. In recognition of this, EVENT is currently in the process of being adopted by the UK nuclear industry. The theory behind EVENT is described and its numerical implementation is outlined. Numerical results obtained by the code are compared with predictions of the Monte ...

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Heat and momentum transport in self-sustained oscillatory viscous flows is investigated by direct numerical simulation using the spectral element method. Above a critical Reynolds number, these flows bifurcate to a time-periodic, self-sustained oscillatory state. Traveling waves are observed, even at moderately low Reynolds numbers, inducing self-sustained oscillations that result in very well-mixed flows, which, in turn, lead to convective heat transfer augmentation. These oscillatory states are investigated and correlations between the time- and space-averaged Nusselt and Reynolds numbers are obtained. The transport phenomena of heat and momentum due to the oscillatory components of the flow are analyzed by looking at the phase portraits of velocity and temperature, investigating the behavior of the terms involving their fluctuations, as well as considering the correlation coefficients between the fluctuating components. ...

International Nuclear Information System (INIS)

Plasma surface interactions in tokamaks are known to create significant quantities of dust, which settles onto surfaces and accumulates in the vacuum vessel. In ITER, a loss of vacuum accident may result in the release of dust which will be radioactive and/or toxic, and provides increased surface area for chemical reactions or dust explosion. A new method of analysis has been developed for modeling dust resuspension and transport in loss of vacuum accidents. The aerosol dynamic equation is solved via the user defined scalar (UDS) capability in the commercial CFD code Fluent. Fluent solves up to 50 generic transport equations for user defined scalars, and allows customization of terms in these equations through user defined functions (UDF). This allows calculation of diffusion coefficients based on local flow properties, inclusion of body forces such as gravity and thermophoresis in the convection term, and user defined ...

International Nuclear Information System (INIS)

The transport of radon in concrete takes place through the complicated network of interconnected pores that is, at any time, the result of the process of hydration of cement and of moisture distribution and transport. Initially the microstructure of concrete depends on the mix proportions and curing conditions, its time-evolution being conditioned by its surrounding environment. Radon transport will be consequently a function of time, as it is influenced by the changing microstructure (total porosity and its distribution) and by the amount and distribution of the moisture contained in the pore system. A selection of information from the large amount of literature available on concrete is presented in chapter 2. A model that describes the process of hydration, of microstructure development and of moisture transport is presented in chapter 3. The physics of radon diffusion in homogeneous porous materials ...

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Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN code. ANISN is a one dimensional ...

International Nuclear Information System (INIS)

For the study of radiation biology and its application to radiotherapy, the double differential cross section of electron emission from water vapor induced by 6.0 MeV alpha particle beam is measured. The energy spectra of electrons ranging 7- 10000 eV are detected by the electrostatic analyzer and micro channel plate. The measurements are made at angles between 20 and 160 degrees. With use of this data set, the radial dose distribution in water is calculated by using KURBUC code. It is the Monte Carlo type code of the electron transport process, where the track of the electron is simulated through each individual interactions including elastic scattering, ionization cross section and total excitation cross section in case that electrons with certain energy are put in the liquid-density water. In order to understand the effect of radiation when the particle flux is injected in the human body like radiotherapy using accelerator beam, the dose ...

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A cryogenic separation method of chloromethane (CH{sub 3}Cl) from methyl iodide (CH{sub 3}I) for {delta}{sup 37}Cl measurement with isotope ratio mass spectrometer is described. A cold trap with sealed 2,2,4-trimethylpentane (TMP) as the cryogen is used in this method. CH{sub 3}Cl can be separated from CH{sub 3}I at the TMP melting point (-107 deg. C) based on the difference in the vapor pressure between CH{sub 3}Cl (322.6 Pa) and CH{sub 3}I (lower than 1.3 Pa) at -107 deg. C. After two-step separation processes, the yields of CH{sub 3}Cl purified from CH{sub 3}Cl-CH{sub 3}I mixture are 96-101%, and the difference between the {delta}{sup 37}Cl{sub original} and {delta}{sup 37}Cl{sub Afterseparation} is from -0.06 to +0.06 per mille (0.01 {+-} 0.04 per mille ). These results suggest that CH{sub 3}Cl is completely separated from CH{sub 3}I with no change of {delta}{sup 37}Cl value. This method using the ...

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The random walk function is a mathematical function derived from studies of the mass transport and flow of diffusible materials through tubes. Approximations to the function were first used some time ago in the field of cardiac tracer dilution curves, but in the absence of rapid and reproducible curve fitting the method never became commonplace. The current study uses the latest curve-fitting techniques and shows how the method may be used with precision in the analysis of time-activity curves from dynamic oesophageal and blood flow studies. The physiological basis of the method is given and parameters obtained which relate to both the rate of flow and the local dispersion of the bolus.

International Nuclear Information System (INIS)

A major deficiency of current photon calculation methods that are based on the concept of primary and scatter separation is their inability to handle the condition of electronic disequilibrium. This deficiency is examined and it is shown that the limitation is not inherent in the algorithms themselves but is, at least in part, in the data which the algorithms use. A new concept of primary and scatter separation is developed to cover the condition of electronic disequilibrium. This new concept requires little change to the existing algorithms and only additional data are required, which are generated using Monte Carlo calculation methods. The new concept is tested using programs in the Theratronics Theraplan treatment-planning system, and two calculation examples illustrate the ability to model electron transport and also the improvement over the existing algorithms. Close analogy of the extended concept with the ...

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Ultratrace analysis of mercury in rain water has been investigated, including recovery of ionic mercury with the addition of acids, treatment and storage and stability studies of mercury in rain water. Recovery of ionic mercury from rain water samples increased with increased acid concentrations and increased substantially with UV-irradiation. Recovery of ionic mercury in the presence of different acids was compared. Treatment studies of rain water for the analysis of total mercury were done using different decomposition methods. More than 20% of the total mercury was found in rain water residue after filtration through 0.45 ..mu..m membrane filters. Methylmercury (MM) content in filtered and unfiltered rain water however was nearly the same. On long term storage of rain water without acids at pH = 2.0 and 4.5 loss of total mercury occurred, but in the presence of acids increasing amounts of ionic mercury were recovered from rain water samples with increasing ...

International Nuclear Information System (INIS)

The reactive evaporation process was successfully used to deposit films of the A-15 Nb_3Ge phase. This is the first report, to the best of our knowledge, illustrating the use of such processes for the deposition of A-15 compounds. In this process, niobium vapors from an electron-beam-heated evaporation source react with germane gas introduced into the vacuum chamber at low partial pressures (approximately 10"-"4 Torr) to produce Nb_3Ge deposits. The process variables studied were the deposition temperature, the niobium-to-germanium impingement ratio on the substrate and the plasma-enhanced deposition, in this case the activated reactive evaporation process. At low deposition temperatures (below 450"0C) the deposit is amorphous (or microcrystalline) and can be crystallized to the Nb_3Ge phase by heat treatment, e.g. at 850"0C for 1 h in vacuum. The ratio of niobium to germanium in the deposit can be varied by changing the process parameters. The films are ...

Energy Technology Data Exchange (ETDEWEB)

On-board reforming of liquid fuels to hydrogen for use in proton exchange membrane (PEM) fuel cell electric vehicles (FCEVs) has been the subject of numerous investigations. In many respects, liquid fuels represent a more attractive method of carrying hydrogen than compressed hydrogen itself, promising greater vehicle range, shorter refilling times, increased safety, and perhaps most importantly, utilization of the current fuel distribution infrastructure. The drawbacks of on-board reformers include their inherent complexity [for example a POX reactor includes: a fuel vaporizer, a reformer, water-gas shift reactors, a preferential oxidation (PROX) unit for CO cleanup, heat exchangers for thermal integration, sensors and controls, etc.], weight, and expense relative to compressed H{sub 2}, as well as degraded fuel cell performance due to the presence of inert gases and impurities in the reformate. Partial oxidation (POX) of automotive fuels is ...

International Nuclear Information System (INIS)

In this paper, we present the results of Plasma-Enhanced Chemical Vapor Deposition gate-oxide (SiO_2) integrity on ELC (excimer-laser-crystallized), MILC (metal-induced lateral-crystallized) and SPC (solid-phase-crystallized) polysilicon films. We observed that gate oxide strength of poly-Si TFT strongly depends on the crystallization method for the active silicon layer. In the case of ELC films, asperities on the silicon surface reduce the SiO_2 breakdown field significantly. The metallic contaminants in MILC films are responsible for a deleterious impact on gate oxide integrity. Among the three cases, the SiO_2 breakdown field was the highest for the SPC silicon films. The breakdown fields at the 50 % failure points in Weibull plots for the ELC, MILC and SPC cases were 5.1 MV/cm, 6.2 MV/cm, and 8.1 MV/cm, respectively. We conclude that the roughness and metallic contamination of the poly-Si films are the main factors that cause enhanced ...

International Nuclear Information System (INIS)

Coaxial nanocables with a single-crystalline zinc telluride (ZnTe) nanowire core and an amorphous silicon oxide (SiO_x) shell have been synthesized via a simple one-step chemical vapor deposition (CVD) method on gold-decorated silicon substrates. The single-crystal ZnTe nanowire core is in zinc-blende structure along the [111] direction, while the uniform SiO_x shell fully covers the core with no observable pin-hole or crack. Formation mechanisms of the ZnTe-SiO_x nanocables are discussed. The ZnTe nanowire core shows p-type electrical properties while the SiO_x shell acts as an effective insulating layer. The ZnTe-SiO_x nanocables may have potential applications in nanoscale devices, such as p-type FETs and nanosensors.

International Nuclear Information System (INIS)

Enhancing transport sustainability is the password of national, European, and international policies. The development of innovative solutions is ranging from bio fuels to transport analysis models, materials, traction technologies, mobility management, freight villages.

International Nuclear Information System (INIS)

The main goal of this paper is to present a methodology for calculating the radioactivity in the moderator and heat transport systems of Cernavoda NPP Unit 1, with the intention to improve the knowledge on the radionuclides inventories in the operational waste streams, and to aid the licensing process of new near surface repository. In the present paper we describe our methodology for estimating H-3 and C-14 production rates in the heavy-water moderator and heat transport systems using the capacity factors from 1997 to 2007 years. The radioactivity of the difficult-to-measure nuclides is predicted by scaling method using measured concentration in reference CANDU 6 reactor Gentilly-2. The difficult-to-measure radionuclides of primary interest in this study were those with long half-lives which have a significant role for post-closure safety assessment. The equation used to scale fission products (parents and daughters) is ...

International Nuclear Information System (INIS)

Scenarios are developed for spent fuel that is taken out of the nuclear reactor and stored for 20 years before reprocessing, and three storage techniques which use a water pool, dry cask or vault are compared with respect to their costs. The storage price (storage cost per kilogram of spent fuel), which is employed as the economic index, is calculated on the assumption that all the charge is paid when the spent fuel is brought in the storage facilities. Four scenarios are assumed for spent PWR and BWR fuels to be stored in at-reactor (AT) or away-from-reactor (AFR) facilities. The capital costs cover the buildings of the storage facilities, equipment, decommissioning, casks for transportation and storage (for cask storage) and casks for transportation (for water pool or vault storage). Costs for operation and maintenance of the facilities are also considered in evaluating these methods. Evaluation results show that the dry ...

Energy Technology Data Exchange (ETDEWEB)

Laser-Induced Breakdown Spectroscopy was selected by NASA as part of the ChemCam instrument package for the Mars Science Laboratory rover to be launched in 2009. ChemCam's Laser-Induced Breakdown Spectroscopy instrument will ablate surface coatings from materials and measure the elemental composition of underlying rocks and soils at distances from 1 up to 10 m. The purpose of our studies is to develop an analytical methodology enabling identification and quantitative analysis of these geological materials in the context of the ChemCam's Laser-Induced Breakdown Spectroscopy instrument performance. The study presented here focuses on several terrestrial rock samples which were analyzed by Laser-Induced Breakdown Spectroscopy at an intermediate stand-off distance (3 m) and in an atmosphere similar to the Martian one (9 mbar CO{sub 2}). The experimental results highlight the matrix effects and the measurement inaccuracies due to the noise accumulated when low signals are ...

International Nuclear Information System (INIS)

This paper presents the effect of precursor powder size on the thermoelectric properties of sintered nanostructured bulk materials. The transport properties of the nanostructured bulk show a dramatic size effect. There are a lower thermal and electrical conductivity for the bulk with smaller nanopowders. The dimensionless figure-of merit values (ZT) of almost all the samples are much lower than those of the list reported data in the paper because the decrease in the thermal conductivity is counteracted by the reduction in the electrical conductivity and the Seebeck coefficient. The combination route of hydro/solvothermal synthesis and spark-plasma-sintering method provide a well controlled way to significantly reduce the thermal conductivity.

International Nuclear Information System (INIS)

It may be stated that for the calculation of the heat transfer coefficients for natural convection cooling of large-diameter finned surfaces it is necessary to take in consideration the effects of the fin length, fin material and of the azimuthal angle around the cylinder. The present results replace earlier less accurate correlations gained from the same measurements. The new, better correlation was elaborated with the aid of the improved method of evaluation of multiple parameters of a measurement matrix of multiple dimension (one dimension for each parameter), rendering the sum of the squares error a minimum at the same time for the complete matrix. 5 references.

Wastenet

... (restricted)] 255-269 Inefficiency of Logit-Based Stochastic User Equilibrium in a Traffic Network Under ATIS by Hai-Jun Huang & Tian-Liang Liu & Xiaolei ...Hub-catchment Areas, Existing Hubs, and Simulation: A Case Study of Serbian Intermodal Terminals by Milorad Vidovic & Slobodan Zecevic & Milorad Kilibarda ... (restricted)] 389-410 Stochastic Location-assignment on an Interval with Sequential Arrivals by Kannan Viswanath & James Ward [Downloadable! (restricted)] ... (restricted)] 193-208 Solving Stochastic Transportation Network Protection Problems Using the Progressive Hedging-based Method by Yueyue Fan & Changzheng Liu [Downloadable! (...

International Nuclear Information System (INIS)

Source-term codes to predict the release of radionuclides from nuclear waste packages have been developed and implemented worldwide. A survey and initial comparison of the attributes and capabilities of 13 international source-term codes was recently completed. This preliminary analysis focused on comparison of transport factors/processes and solution methods. This initial comparison is a necessary first step in a properly-conceived, systematic benchmarking of source-term codes. Advantages of such a comparison include assurance of the mathematical correctness of implemented models, comparison and quantification of variances introduced by different types of simplifications, and identification and quantification of the impact of near-field processes.

Energy Technology Data Exchange (ETDEWEB)

Biogas supply to the public gas grid is a new option discussed in the most recent publication of Fachagentur Nachwachsende Rohstoffe (FNR) e.V. The biogas is purified, upgraded to natural gas quality and fed into an existing gas grid. Once there, it can be transported across long distances and also used for electric power generation at the consumer side. The study investigates inhowfar and in what instances this method is feasible and promising. It discusses the technical background and the regional potential of biogas. Seven model biogas systems are presented as examples. (orig.)

British Library Electronic Table of Contents (United Kingdom)

The Maritime Transportation Security Act of 2002 amended the Deepwater Port Act of 1974 to permit the construction of offshore liquefied natural gas (LNG) terminals. Terminals with environmentally destructive open-loop regasification systems were quickly approved in the Gulf of Mexico. This study analyzed the political methods of the George W. Bush administration to determine how it developed offshore LNG. Findings showed that the Bush administration worked closely with the energy industry to promote national energy security and limited the role of certain federal and state agencies through a centralized policy process.

Energy Technology Data Exchange (ETDEWEB)

Laser optical pumping can be used to produce polarized alkali atom beams or polarized alkali vapor targets. Polarized alkali atom beams can be converted into polarized alkali ion beams, and polarized alkali vapor targets can be used to produce polarized H/sup -/ or /sup 3/He/sup -/ ion beams. In this paper the authors discuss how the polarized alkali atom beams and polarized alkali vapor targets are used to produce polarized ion beams with emphasis on the production of polarized negative ion beams.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

In this dissertation, we design and analyze efficient numerical methods for obtaining accurate solutions to model problems arising in fuel cells. A basic fuel cell model consists of five principles of conservation, namely, mass, momentum, species, charges (electrons and ions), and thermal energy. Overall, transport equations couple with electrochemical processes through source terms to describe reaction kinetics and electro-osmotic drag in the polymer electrolyte. To model multiphase species transport in the porous media and the gas channel of fuel cells, we consider a multiphase mixture model framework. The diffusivity of the two-phase mixture water conservation equation in this model is nonlinear, discontinuous, and degenerate. To handle this difficulty, we developed efficient and fast nonlinear iterative solvers based on the Kirchhoff transformation and nonlinear Dirichlet-Neumann domain decomposition ...

Energy Technology Data Exchange (ETDEWEB)

Using gasoline as an example of additives for cold start improvement, fuel vapor composition of methanol-gasoline mixtures, fuel evaporation rate in consideration of temperature drop due to heat of fuel evaporation, air fuel ratio, stoichiometric air fuel ratio and excess air ratio of fuel vapor were calculated. The mixture formation of methanol-gasoline mixtures at low temperature in otto cycle engines was studied. Van Laar's empirical formula was used to estimate the partial pressure of high-percentage methanol blends. It was found that the most part of fuel vapor is occupied by gasoline, even when a small amount of gasoline is added to methanol resulting to an extremely small excess air ratio. It is obvious that this vapor pressure adjustment using gasoline is the dominant factor for improvement in cold startability. (10 figs, 1 tab, 10 refs)

Energy Technology Data Exchange (ETDEWEB)

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

British Library Electronic Table of Contents (United Kingdom)

In radio signal-based observing systems, such as Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), the water vapor in the atmosphere will cause delays during the signal transmission. Such delays vary significantly with terrain elevation. In the case when atmospheric delays are to be eliminated from the measured raw signals, spatial interpolators may be needed. By taking advantage of available terrain elevation information during spatial interpolation process, the accuracy of the atmospheric delay mapping can be considerably improved. This paper first reviews three elevation-dependent water vapor interpolation models, i.e., the Best Linear Unbiased Estimator in combination with the water vapor Height Scaling Model (BLUE?+?HSM), the Best Linear Unbiased Es...

Science.gov (United States)

Excitonic transitions in metalorganic vapor phase epitaxially grown In[sub [ital x

UK PubMed Central (United Kingdom)

Halothane, chloroform, and carbon tetrachloride, in the vapor and liquid phases, stimulate the water receptor of the blowfly Phormia regina. There are three successive phases of response to long-lasting...Full Text Available

International Nuclear Information System (INIS)

The current trend towards the increased use of risk assessment in the regulation of nuclear power plants will inevitably result in changes in the analysis of fire protection systems and the methods of analysis. Before fire protection can be regulated on a risk basis, a consensus must be reached on a number of issues. One key issue is what types of computational tools will be allowable for analyzing fire events, and what types of scenarios those tools will be approved for use. Reaching this consensus will require an understanding of the types of computational tools available and their inherent advantages and disadvantages. To aid with this understanding, three different methods of fire simulation are applied to an oil pool fire test in the HDR (Heiss Dampf Reaktor) containment test facility. These methods are a hand calculation, the zone model code CFAST (Consolidated Model of Fire Growth and Smoke ...

Science.gov (United States)

This report presents a general investigation of the transport requirements associated with the construction and operation of conceptual fusion reactors. Projections of amounts of construction and operating materials requiring transportation are presented for several proposed designs. The material to be shipped is described along with the shipping containers that might be used, the transport modes and the expected impact of transporting these materials. Transportation of both radioactive and nonradioactive materials will be required. Most of these materials are routinely shipped by the transportation industry. Transportation requirements of a representative fusion reactor are also compared with Liquid Metal Fast Breeder Reactor (LMFBR) requirements.

Energy Technology Data Exchange (ETDEWEB)

Numerical models based on finite-difference or finite-element methods are used by various research groups in studies of radon-222 transport through soil and building materials. Applications range from design of radon remediation systems to more fundamental studies of radon transport. To ascertain that results obtained with these models are of good quality, it is necessary that such models are tested. This document reports on a benchmark test organized by the EU project ERRICCA: European Research into Radon in Construction Concerted Action. The test comprises the following cases: 1) Steady-state diffusive radon profiles in dry and wet soils, 2) steady-state entry of soil gas and radon into a house, 3) time-dependent radon exhalation from a building-material sample. These cases cover features such as: soil heterogeneity, anisotropy, 3D-effects, time dependency, combined advective and diffusive transport ...

Energy Technology Data Exchange (ETDEWEB)

A new opportunity to improve the safety and efficiency of environmental restoration operations, using robotics has emerged from advances in industry, academia, and government labs. Self-Guided Vehicles (SGV`s) have recently been developed in industry and early systems have already demonstrated much, though not all, of the functionality necessary to support driverless transportation of waste within and between processing facilities. Improved materials databases are being developed by at least two DOE remediation sites, the Fernald Environmental Management Project (FEME) in the State of Ohio and the Hanford Complex in the State of Washington. SGV`s can be developed that take advantage of the information in these databases and yield improved dispatch, waste tracking, report and shipment documentation. In addition, they will reduce the radiation hazard to workers and the risk of damaging containers through accidental collision. In this document, features of remediation ...

Energy Technology Data Exchange (ETDEWEB)

Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the subsurface; and field testing and evaluation of methods proposed to restore and ...

Energy Technology Data Exchange (ETDEWEB)

Radon proof barriers are used for lowering of radon transport from the soil into the house and the determination of the radon diffusion coefficient is an important parameter to be determined in order to design the minimal thickness of the radon proof insulation. A method has been developed in our laboratory by using modified Lucas cells connected to a radon source and tightly closed onto the top by the tested membranes whose radon diffusion coefficients are being measured. Solving the time-dependent differential equation for radon diffusion in the membrane for well-defined experimental conditions the effective radon diffusion coefficient of the insulating material can be evaluated by comparing the radon concentration decrease in the cell for the first hours with the well-known radioactive decay. First results obtained in several preliminary tests carried out with a parafilm M barrier and two polyethylene membranes are shown in this paper.

International Nuclear Information System (INIS)

Methods currently being used or developed for the elemental analysis of materials are chemical analysis, non-destructive inspection and calorimetry. The chemical analysis, which removes high-level radioactive elements through chemical treatments and then performs the quantitative analysis using the ICP-MS(Inductively Coupled Plasma - Mass Spectrometer) or the ID-MS(Isotope Dilution Mass Spectrometer), is recognized the most accurate. However, it requires a long, complex pre-treatment process in which a mass spectrometer could be contaminated. To solve this problem, a new method, which can be performed with high-level radioactivity and at high temperature, was desired. Such a method should also have the same accuracy as the chemical analysis, with a less possibility for instruments to be contaminated. In addition, as interests in the environment and the life quality are increased, a detailed analysis on the environmental ...

Energy Technology Data Exchange (ETDEWEB)

An important component of the overall program to validate WIMS-AECL for use with RFSP in the analysis of CANDU-6 reactors for design and safety analysis calculations is the validation of calculations of incremental cross sections used to represent reactivity devices. A method has been developed for the calculation of the three-dimensional neutron flux distribution in and around CANDU reactor fuel channels and reactivity control devices. The methods is based on one- and two dimensional transport calculations with the WIMS-AECL lattice cell code, SPH homogenization, and three-dimensional flux calculations with finite-difference diffusion theory using the MULTICELL code. Simulations of Wolsung 1 Phase-B commissioning measurements and Point Lepreau restart tests have been performed, as a part of the program to validate WIMS-AECL lattice cell calculations for application to CANDU reactor simulations in RFSP. The incremental ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports on three-dimensional continuous-energy coupled neutron-gamma Monte Carlo models of the Advanced Neutron Source (ANS) final preconceptual and conceptual reference core designs developed using the Monte Carlo Neutron and Photon transport code (MCNP) Version 3b. These models contain the reactor core with control rods, the heavy water reflector tank with shutdown rods and some beam tubes, and the outer light water pool. Eighty homogenized fuel zones per fuel element are used to represent the radial and axial {sup 235}U fuel distribution. These models are the most sophisticated, physically accurate reactor physics models of the ANS currently available. The use of MCNP methods and applications to the ANS are demonstrated. Beam tube studies, coolant voiding studies, and many criticality studies have already been performed, as have studies with variance reduction techniques. In comparison with deterministic ...

Energy Technology Data Exchange (ETDEWEB)

This document provides stakeholder evaluations on innovative technologies to be used in the remediation of volatile organic compounds from soils and ground water. The technologies evaluated are; in-well vapor stripping, in-situ bioremediation, and gas membrane separation.

Energy Technology Data Exchange (ETDEWEB)

This project dealt with use of condensing heat exchangers to recover water vapor from flue gas at coal-fired power plants. Pilot-scale heat transfer tests were performed to determine the relationship between flue gas moisture concentration, heat exchanger design and operating conditions, and water vapor condensation rate. The tests also determined the extent to which the condensation processes for water and acid vapors in flue gas can be made to occur separately in different heat transfer sections. The results showed flue gas water vapor condensed in the low temperature region of the heat exchanger system, with water capture efficiencies depending strongly on flue gas moisture content, cooling water inlet temperature, heat exchanger design and flue gas and cooling water flow rates. Sulfuric acid vapor condensed in both the high temperature and low temperature regions of the heat ...

Energy Technology Data Exchange (ETDEWEB)

Measurements of the double-electron-capture process in which a positive ion of iodine becomes a negative ion in a single collision with a magnesium atom are reported between 20 and 90 keV. The cross section is comparable to that for the rare gases and not as large as might be expected from a two-valence-electron atom. This process is probably insignificant in the production of negative ion beams using a magnesium-vapor target.

Energy Technology Data Exchange (ETDEWEB)

The adsorption of mercury vapor on particles was studied by using soot particles generated by incineration of sewage sludge (EP-ash) and activated carbon particles. Through the experiments, it was found that, at 298 K, the EP-ash has a fairly high adsorption capacity for mercury vapor in the order of 10/sup -6/g/g, which is between that of the ordinary soils and that of activated carbon particles. Furthermore, it was found that physical adsorption of mercury vapor on the studied particles at high temperature is described by Dubinin's equation. On the basis of the equation, it was shown that EP-ash physically adsorbs very little mercury at high temperature, and therefore, most mercury in the EP-ash is chemically adsorbed or contained in a form of mercury compounds. Nevertheless, the total amount of mercury contained in the particles is very little compared to the total mercury in the exhaust gases so that most ...

Energy Technology Data Exchange (ETDEWEB)

In a scenario of aqueous transport from a high-level radioactive waste repository, the concentration of radionuclides in water in contact with the waste constitutes the source term for transport models, and as such represents a fundamental component of all performance assessment models. Many laboratory experiments have been done to characterize release rates and understand processes influencing radionuclide release rates from irradiated nuclear fuel. Natural analogues of these waste forms have been studied to obtain information regarding the long-term stability of potential waste forms in complex natural systems. This information from diverse sources must be brought together to develop and defend methods used to define source terms for performance assessment models. In this manuscript examples of measures of radionuclide release rates from spent nuclear fuel or analogues of nuclear fuel are presented. Each example ...

International Nuclear Information System (INIS)

Ti-15Mo-2.7Nb-3Al-0.2Si (Timetal-21S), a metastable #beta#-titanium alloy, is a candidate material for titanium matrix composite structures in hydrogen-fueled hypersonic planes because of its excellent formability and adequate mechanical properties in the 500--800 C temperature range. The alloy is strengthened through the precipitation of fine #alpha# particles in the #beta# matrix. The mechanical properties and microstructures are controlled by a solutionizing/aging heat treatment. A major concern in using titanium alloys in hydrogen service is the embrittlement caused by the precipitation of hydrides. It is believed that the large solubility of hydrogen in the #beta#-phase would preclude the precipitation of hydrides in Beta titanium alloys, especially at low hydrogen pressures. However, depending on the hydrogen content, a shift in the ductile/brittle transition temperatures to levels much higher than room temperature has been reported for Timetal-21S alloy. The objective of the ...

Energy Technology Data Exchange (ETDEWEB)

Managing sites contaminated with munitions constituents is an international challenge. Although the choice of approach and the use of Ecological Risk Assessment (ERA) tools may vary from country to country, the assurance of quality and the direction of ecotoxicological research are universally recognized as shared concerns. Drawing on a multidisciplinary team of contributors, 'Ecotoxicology of Explosives' provides comprehensive and critical reviews available to date on fate, transport, and effects of explosives. The book delineates the state of the science of the ecotoxicology of explosives, past, present, and recently developed. It reviews the accessible fate and ecotoxicological data for energetic materials (EMs) and the methods for their development. The chapters characterize the fate of explosives in the environment, then provide information on their ecological effects in key environmental media, including aquatic, ...

Energy Technology Data Exchange (ETDEWEB)

The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have ...

International Nuclear Information System (INIS)

Debris coolability in the lower plenum of the reactor pressure vessel is an important factor for evaluation of debris in-vessel retention. The debris coolability analysis module is developed for the accurate prediction of the safety margin of the present reactor vessels in a severe accident. The module calculates debris spreading and cooling through melting and solidification in combination with a temperature distribution and failure evaluation of the vessel wall. Debris spreading is solved by the explicit method on a quasi-three-dimensional scheme and debris coolability is solved on the basis of natural convection analysis. The calculation for spreading is compared with a water spreading experiment on the floor and the calculation for coolability is compared with a n-octadecane melting experiment in a rectangular vessel. The comparisons show capabilities for predictions of spearhead transportation in the debris spreading process and of melting ...

International Nuclear Information System (INIS)

Full text: The principal nuclear design tools available to the shielding designer include diffusion approximation, transport theory, and Monte Carlo techniques. Full transport theory or Monte Carlo methods are routinely used for shielding analyses, where penetration investigations are more sensitive to directional aspects. However, the aim of this paper is to illustrate the coupled neutron-gamma Albedo method particularly as applied to problems of shielding analysis. The multigroup Albedo method is applied to coupled neutron-gamma radiations considering 'n' neutron energy groups and 'g' gamma energy groups to estimate the probabilities of transmission through, absorption in, and reflection from shieldings composed by multiple material layers, 'm' slabs, in which no fission occurs. In this study, these energy groups were selected in order to minimize upscattering effects of the ...

International Nuclear Information System (INIS)

Ti and its alloys (Ti-6Al-4V) have been used in different engineering applications due to their several outstanding properties. Nevertheless, their use in practical applications is limited in many cases due to their poor tribological property. Researches are ongoing on surface modification of Ti based materials by different plasma and ion based techniques to overcome this problem. However, the conventional plasma nitriding techniques have several problems such as formation of an arc, increased possibility of surface contamination due to a comparatively higher operating pressure, production of a very thin nitrided layer after a long processing time, etc. In this present work, the possibility of a new low-pressure plasma nitriding process using a Plasma Enhanced Chemical Vapor Deposition (PECVD) based saddle field fast atom beam source on a Ti-6Al-4V alloy sample is investigated. Plasma nitriding was carried out at 900 deg. C and at a pressure 0.1 Pa for 8 h by using ...

Energy Technology Data Exchange (ETDEWEB)

Successful interface engineering requires compositional and electronic material characterization as a prerequisite for understanding and intentionally generating interfaces in photovoltaic devices. The paper gives an overview with several examples, all referring to Cu(In,Ga)(S,Se){sub 2} ('CIGSSe')-based solar cells, with an emphasis on characterization using highly specialized methods, such as elastic recoil detection analysis, X-ray emission spectroscopy and photoelectron spectroscopy using synchrotron and ultraviolet light for excitation, inverse photoemission spectroscopy and Kelvin probe force microscopy. First, the determination of the depth profile of the band gap energy E{sub g} in the absorber layer is demonstrated. The modification of E{sub g} towards both interfaces is discussed in terms of beneficial electronic effects. Next, the interface between absorber and buffer layers with alternative and promising non-toxic materials is ...

Energy Technology Data Exchange (ETDEWEB)

The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the ...

Energy Technology Data Exchange (ETDEWEB)

The Danish Ministry of Transportation has prepared a national plan of transportation, for the years until 2005. Official policy concerning land, maritime and air transport, personal and cargo transportation, investments and expenditures is outlined. Environmental impacts of energy consumption and air pollution abatement measures are considered. (EG)

Energy Technology Data Exchange (ETDEWEB)

Experiments with fresh PWR fuel assemblies were performed to assess the {sup 252}Cf-source-driven frequency analysis method for measuring the subcriticality of spent fuel. The measurements at the Babcox and Wilcox Critical Experiments Facility mocked up between 17x17 fuel pins (single assembly) and a full array of 4961 fuel pins (about 17 fuel assemblies) in borated water with a fixed B concentration. For the full array, the B content of the water was varied from 1511 at delayed criticality to 4303 ppM. Measurements were done for various source-detector-fuel pin configurations; they showed high sensitivity of frequency analysis parameters to B content and fissile mass. Parameters such as auto and cross power spectral densities can be calculated directly by a more general model of the Monte Carlo code (MCNP-DSP). Calculation-measurement comparisons are presented. This model permits the validation of neutron and gamma ray transport calculational ...

Energy Technology Data Exchange (ETDEWEB)

The {sup 252}Cf-source-driven frequency analysis method can be used for measuring the subcritical neutron multiplication factor of arrays of LWR fuel and as little as a single PWR fuel assembly. These measurements can be used to verify the criticality safety margins of spent LWR fuel configurations and thus could be a means of obtaining the information to justify burnup credit for spent LWR transportation/storage casks. In addition, the data can be used to validate calculational methods for criticality safety. These measurements provide parameters that have a higher sensitivity to changes in fissile mass than neutron multiplication factor and thus serve as a better test of calculational methods. The analysis have also shown that measurement of the cross power spectral density (CPSD) between detectors on one side of a single fuel assembly and an internal or external {sup 252}Cf source driving the fission ...

Energy Technology Data Exchange (ETDEWEB)

A dust extraction system removes the contaminated air at source by means of a hood. The extraction system for dust is essentially a ducted air system that prevents excessive employee exposure to dust in the working zone. The four major mechanisms that remove the contaminants in an extraction system are: - capture of contaminants by hoods - transport of contaminated air in duct network - separation of dust in the collector - exhaust of clean air through stack. The current methods of design are based on empirical relations, multi-variable tables, graphs and nomographs that have been derived from the principle of fluid mechanics and particle dynamics. However, the empirical formulae, tables and graphs are used in different geographical locations of the world having different environmental conditions and geo-characteristics of dust particles. Therefore, it is required to establish a rational design method that will be based on ...

International Nuclear Information System (INIS)

The computer programme COMMIX-2 describes steady state and transient multidimensional single- and two-phase fluid flows with heat transfer in nuclear reactor components and multicomponent systems. Originally from the Argonne National Laboratory, the code has been further developed at the Kernforschungszentrum Karlsruhe. The original Point-SOR iterative method for the solution of a Poisson-like equation describing the pressure distribution in the fluid as well as the transport of enthalpy and turbulent quantities has been complemented with iterative and direct line- and block-methods. None of the newly implemented methods is original in itself but their implementation into the computer code, which can describe the most general shapes of definition domains, gave a code speed-up by a factor of 2-5, depending on the problem treated. The code capabilities are assessd by the calculation of a benchmark problem ...

Energy Technology Data Exchange (ETDEWEB)

A modified accumulator was devised to measure surface radon flux from porous media. It consists of a collector hood accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate for any pressure changes produced during sample withdrawl and hence eliminate additional radon transport from media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation. Core samples from the observation site were withdrawn for laboratory determination of porosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media. ...

International Nuclear Information System (INIS)

A modified accumulator was devised to measure surface radon flux from porous media. It consists of a collector hood accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate for any pressure changes produced during sample withdrawl and hence eliminate additional radon transport from media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation. Core samples from the observation site were withdrawn for laboratory determination of pkrosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media. ...

UK PubMed Central (United Kingdom)

ATP-binding cassette transporters (ABC transporters) utilize the energy of ATP hydrolysis to translocate an unusually diverse set of substrates across cellular membranes. ABCA4, also known as...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Transport of negative ion beams through plasma is reviewed. The effect of space charge on beam stability and beam emittance is discussed. The approaches to the beam transport problem developed at Los Alamos, Berkeley, Oak Ridge and Culham Laboratory are intercompared. (AIP)

UK PubMed Central (United Kingdom)

To gain insight into ATP-binding cassette transporter A1 (ABCA1) function and its potential role in AD pathology, we analyzed the expression of the cholesterol transporter ABCA1...Full Text Available

UK PubMed Central (United Kingdom)

Many auxin responses are dependent on redistribution and/or polar transport of indoleacetic acid. Polar transport of auxin can be inhibited through the application of phytotropins such as 1-naphthylphthalamic...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Experiments have been carried out in water at 355 C to study transport of oxygen and hydrogen (as deuterium) in growing corrosion films. Composition of the films was also examined in 2.9 Mev and 3.9 Mev /alpha/-particle backscattering experiments. Corrosion occurs predominantly by oxygen diffusion through the film via grain boundary or similar short circuit diffusion paths, to form fresh oxide at the oxide metal interface. Increasing grain size within thick pre-breakaway films contributes to a decrease in diffusivity. The rate transition results from the generation of new diffusion pathways in previously protective oxide. Unexpectedly high concentrations of deuterium were observed. 26 refs.

International Nuclear Information System (INIS)

Three new phases with compositions, LaSr_2FeTiO_7, NdSr_2FeTiO_7 and GdSr_2FeTiO_7, were prepared by the traditional ceramic method. Lazy-Pulverix analysis of the X-ray diffraction data suggests that the phases crystallize in the RP-type (n = 2) structure in the space group, I4/mmm. The cell dimensions along the c-axis decrease with decrease in size of the rare earth ions. Electrical resistivity, as a function of temperature, shows that the materials are insulators and the resistivity decreases with decrease in the size of the rare earth ion, which is attributed to increase in the three-dimensional character. (author)

CERN Document Server

Spatial Fluorescence Cross Correlation Spectroscopy is a rarely investigated version of Fluorescence Correlation Spectroscopy, in which the fluorescence signals from differ-ent observation volumes are cross-correlated. In the reported experiments, two observation volumes, typically shifted by a few $\\mu$m, are produced, with a Spatial Light Modulator and two adjustable pinholes. We illustrated the feasibility and potentiality of this technique by: i) measuring molecular flows, in the range 0.2 - 1.5 $\\mu$m/ms, of solutions seeded with fluorescent nanobeads or rhodamine molecules (simulating active transport phenomenons); ii) investigating the perme-ability of phospholipidic membrane of Giant Unilamellar Vesicles versus hydrophilic or hydrophobic molecules (in that case the laser spots were set on both sides of the mem-brane). Theoretical descriptions are proposed together with a discussion about FCS based, alternative methods.

Energy Technology Data Exchange (ETDEWEB)

The 1992 New Mexico State Legislature directed the Interstate Stream Commission (ISC) to study the feasibility of clearing and deepening the channel of the Rio Grande between Albuquerque and Elephant Butte to improve water conveyance and water conservation. The ISC requested the US Army Corps of Engineers-Albuquerque District (COE) to undertake this study under the Planning Assistance to States Program. The study was divided into two phases. Phase 1 consisted of an analysis of the sediment contribution to the Rio grande from the tributaries and an evaluation of the existing US Geological Survey (USGS) sediment gage data. Phase 2 will be an analysis, through the use of an HEC-6, Scour and Deposition in Rivers and Reservoirs, computer model, to determine the long-term performance of any Rio Grande channel improvements. This narrative presents the Phase 1 methods and results.

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...

British Library Electronic Table of Contents (United Kingdom)

This paper presents a method to evaluate and improve the performance of quantum dot infrared photodetectors (QDIPs). We proposed a device model for QDIPs. The developed model accounts for the self-consistent potential distribution, features of the electron capture and transport in realistic QDIPs in dark and illumination conditions. This model taking the effect of donor charges on the spatial distribution of the electric potential in the QDIP active region. The model is used for the calculation of the dark current, photocurrent and detectivity as a function of the structural parameters such as applied voltage, doping QD density, QD layers, and temperature. It explains strong sensitivity of dark current to the density of QDs and the doping level of the active region. In order to confirm our...

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Monte Carlo neutron transport methods can be used to verify the applicability of point kinetics for safety analysis of nuclear reactors. KENO-NR was used to obtain the transfer function of the Advanced Neutron Source reactor and the time delay between the core power production and the external detectors, a parameter of interest to the safety systems design. The good agreement between the Monte Carlo generated transfer function and the point kinetics transfer function validates that the uncommon ANS geometry does not preclude the use of point kinetics in the frequency range that was investigated. Various features of the power spectral densities also demonstrated the applicability of point kinetics. The time delay was obtained from the cross-power spectral density (CPSD) and is {approximately}15 ms. These analyses show that frequency analysis can be used experimentally to investigate the validity of the use of point kinetics models in critical ...

International Nuclear Information System (INIS)

An effective method of enhancing charge injection and electroluminescence efficiency of polymer-based light emitting diode is introduced. Spin-coated films of poly (N-vinylcarbazole) blended with electron-transport material (Bu-PBD), laser dye (Coumarin6), and the typical supporting electrolyte (tetraethylammonium perchlorate; TEAP) were examined and it was found that the injection current and luminance of the light emitting diode doped with TEAP were enhanced dramatically after heat-treatment at 80 deg. C and appropriate biasing in an external electric field of 1.5x10"8 V/m at this temperature. The thermally stimulated current (TSC) was also measured to investigate the relaxation process of ionic space charges in the films. The relaxation times of ionic polarization were found to be related to the cation size of the electrolyte. And the relaxation time becomes long enough by the use of TEAP doping.

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The alpha-particle confinement of future D-T experiments at JET can be severely degraded by Global Alfven Eigenmodes (AE). Scenarios for the excitation of Alfven Eigenmodes in usual (e.g. D-D) plasmas are proposed, which provide a MHD diagnostic and allow the study of the transport of super-Alfvenic ions. Active studies with separate control of TAE amplitude and energetic particle destabilization, measuring the plasma response, give more information than passive studies, in particular concerning the damping mechanisms. The TAE excitation can be achieved by means of the saddle coil and the ICRH antenna. The experimental method is introduced together with a theoretical model for RF excitation. (authors). 6 refs., 3 figs.

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Often oil/gas and other hydrocarbons discovered and produced offshore are transported to onshore facilities via submarine pipelines. The route of such pipelines traverses through coastal/shore approach regions. For a rational/economic design, safe installation and subsequent operation it is of utmost importance to review, evaluate and finalize various environmental hazard such as winds, waves, currents, seabed topography, seabed and sub-bottom soils, seabed erosion and soil accretion. This paper addresses the above described environmental hazards, their assessment and techniques to prepare design parameters which must be used for stability analysis, installation methods, long term operation and maintenance for the shore approaches. Additionally, various proven pipeline installation and stabilization techniques for the shore approach region are detailed. As case histories, three approaches installed in the Dutch North Sea are described.

International Nuclear Information System (INIS)

Various theories and examples of modelling, forecasting and optimization designing in the different parts of the petroleum and gas industries are presented, stochastic programming for long term planning in the refining industry, stochastic model for gasoline blending, feedstock optimization, location and sizing for offshore platforms, hydrocarbon exploration simulation rapid method, valuation of oil field development leases, economic models for petroleum allocation, models for oil supply market, trade embargo game theory, stochastic programming of gas contract portfolio management, scheduling transportation of oil and gas, strategic planning in an oil pipeline company, simulation of offshore oil terminal systems, hierarchical selection of oil and gas distribution systems.

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Real-time neutron radiography has been used to study the dynamic behavior of two-phase flow and measure vapor fractions in a steam-water duct at atmospheric pressure. This unique experimental technique offers one the opportunity to observe and record on videotape now Patterns and transient behavior of two-phase flow inside opaque containers without perturbing the environment. The neutron radiographic technique is non-intrusive and requires no special transparent window region. Data are recorded simultaneously over a large area of interest. Image processing of the video data can be employed to measure bubble velocities and time-averaged and Instantaneous vapor fractions.

Science.gov (United States)

We present a numerical model of vapor-dominated reservoirs which is based on the well-known conceptual model of White, Muffler, and Truesdell. Computer simulations show that upon heat recharge at the base, a single phase liquid-dominated geothermal reservoir in fractured rock with low matrix permeability will evolve into a two-phase reservoir with B.P.D. (boiling point-for-depth) pressure and temperature profiles. A rather limited discharge event through cracks in the caprock, involving loss of only a few percent of fluids in place, is sufficient to set the system off to evolve a vapor-dominated state. The attributes of this state are discussed, and some features requiring further clarification are identified. 26 refs., 5 figs.

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A study was made of employee exposure to oil sludge and vapors during oil-sludge removal and maintenance activities at the Alyeska Pipeline Service Company's Ballast Water Treatment Facility, Valdez, Alaska. Total hydrocarbons, except benzene, toluene, and xylene, showed concentrations from 371 to 1228mg/m3. Of eight maintenance workers, five reported headache, dizziness, or nausea when working without a respirator. The authors conclude that workers were potentially exposed to benzene vapors and total hydrocarbon vapors exceeding the evaluation criteria for these substances. The authors recommend the use of respiratory protection measures to reduce exposures during work operations.

Energy Technology Data Exchange (ETDEWEB)

Neutron radiography systems are being used for real-time visualization of the dynamic behavior as well as time-averaged measurements of spatial vapor fraction distributions for two phase fluids. The data in the form of video images are typically recorded on videotape at 30 frames per second. Image analysis of he video pictures is used to extract time-dependent or time-averaged data. The determination of the average vapor fraction requires averaging of the logarithm of time-dependent intensity measurements of the neutron beam (gray scale distribution of the image) that passes through the fluid. This could be significantly different than averaging the intensity of the transmitted beam and then taking the logarithm of that term. This difference is termed the dynamic error (error in the time-averaged vapor fractions due to the inherent time-dependence of the measured data) and is separate from the static error (statistical ...

International Nuclear Information System (INIS)

Hydrogen (H) plasma treatment, oxygen (O) plasma treatment and water (H_2O)-vapor heat treatment for polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) have been analyzed by separately extracting trap density at a front silicon-oxide interface (D_F) and trap density at a back interface (D_B). It is found that the H plasma treatment is apt to generate D_F and D_B. The O plasma treatment reduces D_F, while the H_2O-vapor heat treatment reduces both D_F and D_B. Improvement of transistor characteristics of poly-Si TFTs depends on understanding these results.

UK PubMed Central (United Kingdom)

BackgroundWith the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional...Full Text Available

UK PubMed Central (United Kingdom)

The relative transport capabilities of the cells of the root periphery and cortex were investigated using a variety of experimental techniques. Brief (30 seconds to 1 minute) exposures with the penetrating...Full Text Available

International Nuclear Information System (INIS)

This report was prepared to evaluate the compliance of Cask Transportation Facility Modifications (CTFM) to DOE Order 6430.1A.

Energy Technology Data Exchange (ETDEWEB)

The UNSAT-H model was developed at Pacific Northwest National Laboratory (PNNL) to assess the water dynamics of arid sites and, in particular, estimate recharge fluxes for scenarios pertinent to waste disposal facilities. During the last 4 years, the UNSAT-H model received support from the Immobilized Waste Program (IWP) of the Hanford Site's River Protection Project. This program is designing and assessing the performance of on-site disposal facilities to receive radioactive wastes that are currently stored in single- and double-shell tanks at the Hanford Site (LMHC 1999). The IWP is interested in estimates of recharge rates for current conditions and long-term scenarios involving the vadose zone disposal of tank wastes. Simulation modeling with UNSAT-H is one of the methods being used to provide those estimates (e.g., Rockhold et al. 1995; Fayer et al. 1999). To achieve the above goals for assessing water dynamics and estimating recharge rates, the ...

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Significant ion irradiation during film growth is required for the formation of cubic boron nitride (cBN) films. Meanwhile, a huge level of intrinsic stress possibly induced by the ion bombardment has been frequently reported to result in cracking and/or lack of adhesion of deposited cBN films. The present work has been performed to investigate the interfacial and/or the buffer layer structures with better matching to the cBN film by relaxation of the film stress using ion-beam-assisted deposition (IBAD). Boron nitride films have been synthesized on Si(100) wafer and tungsten carbide (WC) substrates by depositing boron vapor under simultaneous bombardment with nitrogen ions and nitrogen-argon mixture ions in the energy range of 0.5-10 keV. Cubic BN films with enhanced tribological properties have been explored by inserting a BN layer with various B/N compositions as a controlled buffer at the interface. Significant relaxation of the film stress has been observed ...

International Nuclear Information System (INIS)

The molar heat capacities of chloroform, dichloromethane, methanol, acetonitrile, acetone, dimethyl sulfoxide, benzene, dimethylformamide, toluene, and cyclohexane, as well as their deuterated isotopologues, were measured using a multi-channel heat conduction TAM (Thermal Activity Monitor) III microcalorimeter. In addition, the apparent molar heat capacities of some of the associated dilute aqueous solutions (0.0039 i < 0.0210) were also measured. A temperature drop method from (298.15 to 297.15) K at 0.1 MPa was employed. The corresponding heat capacities were determined from the integration of the measured heat flow. The heat capacity results are shown to be in good to very good agreement with the available literature values. In addition, good correlations were obtained for the effect of isotopic substitution on both molar heat capacity and apparent molar heat capacity in aqueous solutions. These correlations should be useful in the prediction of the molar ...

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The methodology of achieving a high power density (HPD, or brake mean effective pressure) direct-injection Diesel engine has been studied, which is directed to using high fuel/air ratio, high-speed and ceramic engine components. Among the main thrust to achieve these engine changes for an advanced Diesel engine is the design of a high injection pressure (HIP) fuel system. During the course of the present study, two Cummins 903 engines mated with a Rutger-built HIP were employed to investigate the engine response to HIP and in-cylinder processes by using the Rutgers high-speed infrared (IR) spectral digital imaging system. Five separate technical publications were prepared to report results obtained from the study. The main findings include: The HIP system permits engine operation at an air/fuel ratio of as rich as 18 to 1 with smoke emission not worse than with the conventional mechanical (low pressure) injection system; A high injection pressure improves HPD of a Diesel engine; A HIP ...

UK PubMed Central (United Kingdom)

For terrestrial animals and plants, a fundamental cost of living is water vapor lost to the atmosphere during exchange of metabolic gases. Here, by bringing together previously developed models for...Full Text Available

Science.gov (United States)

A dielectric liquid having entrained bubbles of gas or vapor is subjected to an electric field applied between spaced electrodes (112, 116) which generates microdischarges (and thus plasma) within the bubbles, allowing modification of the properties of th...

International Nuclear Information System (INIS)

Nuclear energy provides a third of Europe's electricity with nearly no greenhouse-gas emissions. Sustained efforts are now being conducted to harmonize regulations all over Europe through WENRA and to converge on technical nuclear safety practices within the TSO network ETSON (European Technical Safety Organizations Network). In CANDU type NPP the tritiated water occurs by the neutron bombardment of deuterium. The tritiated water vapors imply health hazard (in the critical organs of the body the water presents a 10 day average biological half-life) and the early detection in nuclear plants of tritium emissions is important because the tritiated water vapors have the same characteristics as of atmospheric water vapors. By detecting tritiated vapors, the monitoring system ensures the following objectives: (a) indicates levels of tritium generally due to heavy water leakage, (b) reduces the possibility of ...

Energy Technology Data Exchange (ETDEWEB)

Explosives molecules have a number of unique properties. These properties are discussed. They include low vapor pressures, electronegativity, ''stickiness,'' frangibility, and thermal instability. The program for developing an advanced explosives detector is described.

Energy Technology Data Exchange (ETDEWEB)

There are certain factors to take into account when determining the suitability of a healthy house site. Power lines, agricultural spraying, vehicle exhaust, and industrial pollution are all potential sources of indoor air contamination. It is recommended that a environmental assessment be done to determine whether there are specific sources of contamination. Good drainage is required. The surrounding landscaping should be open and sunlit, and with low maintenance requirements. Decks and fences made from pressure-treated or chemical treated lumber should be avoided. One of the early decisions in the design process is the choice of the structural system. The key with all foundation types is to control moisture, whether from rain, from the ground, or the condensation of moisture from the air with cooling. The construction frame is sealed away from the occupants by the air/vapor barrier, so only in extreme cases is it essential to use alternatives to softwood lumber ...

Science.gov (United States)

Mar 1, 2011 ... The movement of hydrothermal fluids and/or fumarolic vapors through local rocks prior ... The Solar Energetic Particle Event of December 14, 2006 .... for measurement of non-precipitating cloud hydrometeors and aerosols, ...

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In this paper uptake of tritium by market foods from tritiated water vapor in the air is investigated using cereals and beans purchased in Deep River, Canada. The concentrations of tissue free water tritium (TFWT) and organically bound tritium (OBT) range from 12 to 79% and from 10 to 38% respectively, of that estimated for atmospheric water vapor of the sampling month. The specific activity ratios of OBT to TFWT were constant for cereals, but variable for beans. The elevated OBT was shown to be the result of isotopic exchange of labile hydrogen by the fact that washing the foods with tritium free-water reduced their tritium contents to levels characteristic of their production sites.

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The production of polarized negative ion beams by collisional pumping is described. Collisional pumping utilizes repeated charge changing collisions in a thick electron-spin-polarized gas or vapor target to form a polarized fast atom beam. The polarized fast atom beam is then partially converted into a polarized negative ion beam in a vapor target. Analysis is presented for a hydrogen beam passing through either a thick polarized H atom target or a thick polarized alkali target. Large polarizations and large currents may be possible.

Science.gov (United States)

Plasma generated in low-density vapor by a negative ion beam has been studied experimentally and computationally. We show that space charge neutralization of the beam occurs at very low vapor density, and that correspondingly the electron density may be much less than the beam and plasma ion densities. When there is a large local gas density, as in a charge changing cell, the resulting high electron density is also localized to the same region. Therefore, very few electrons will reach a negative ion accelerator even if it is placed one or two beam diameters from such a cell.

International Nuclear Information System (INIS)

A thermodynamic model was used to estimate enthalpy of solution of carbon dioxide (CO_2) in methyldiethanolamine (MDEA) aqueous solutions. The model was based on a set of equations for chemical equilibria, phase equilibria, charge, and mass balances. Non-ideality in the liquid phase was taken into account by interaction parameters fitted to (vapor + liquid) equilibrium data. The enthalpies of solution of CO_2 were derived from the model using classical thermodynamic relations and were compared to experimental values obtained in previous works.

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In this paper the diffusion of tritiated water vapor into concrete walls is studied to evaluate tritiated water retention capacity of a fusion reactor concrete building. Using a model of the tritiated water diffusion determined form experimental results, depth profiles of tritiated water in concrete are calculated in the case of being exposed to air containing tritiated water vapor during the normal operational condition of a fusion reactor. A 0.5-m-thick concrete is sufficient for reactor hall walls from a viewpoint of the tritium containment.

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Reactor pressure vessel (RPV) steels are subjected to neutron irradiation at a temperature of about 290 deg C. This radiation exposure alters the mechanical properties, leading to a shift of the brittle-to-ductile transition temperature toward higher temperatures and to a diminution of the rupture energy as determined by Charpy V-notch tests. This radiation embrittlement is one of the important aging factors of nuclear power plants. U.S. NRC recommended the basic requirements for the determination of the pressure vessel fluence by regulatory guide DG-1025 in order to reduce the uncertainty in the determination of neutron fluence calculation and measurements. The determination of the pressure vessel fluence is based on both calculations and measurements. The fluence prediction is made with a calculation and the measurements are used to qualify the calculational methodology. Because of the importance and the difficulty of these calculations, the method`s ...

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Maintaining uniformity of properties over long distances is one of the fabrication problems encountered with the new high {Tc} superconductors. Uniform properties are crucial in long tapes or wires with high critical current since local nonuniformities can limit the current carrying capacity of the whole piece. Transport critical currents in high {Tc} superconductors are conventionally measured with the contact 4-point probe DC current-voltage technique. This technique requires contact with the sample and and spatially averages over the region between the two voltage contacts. Two techniques have been used to infer the critical state model. The first uses the net magnetization of a suitably shaped sample in an external magnetic field. The second combines a DC magnetic field with AC induced currents to infer spatial flux profiles. The AC magnetization technique offers an advantage in that it is noncontacting; however, it also averages the measurement over a large ...

Energy Technology Data Exchange (ETDEWEB)

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of ...

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SYVAC3 (Systems Variability Analysis Code, generation 3) is a computer program that implements a method called systems variability analysis to analyze the behaviour of a system in the presence of uncertainty. This method is based on simulating the system many times to determine the variation in behaviour it can exhibit. SYVAC3 specializes in systems representing the transport of contaminants, and has several features to simplify the modelling of such systems. It provides a general tool for estimating environmental impacts from the dispersal of contaminants. This report describes the use and structure of SYVAC3. It is intended for modellers, programmers, operators and reviewers who deal with simulation codes based on SYVAC3. From this manual they can learn how to link a model with SYVAC3, how to set up an input file, and how to extract results from output files. The manual lists the subroutines of SYVAC3 that are available ...

Energy Technology Data Exchange (ETDEWEB)

Compares methods used at CEGB (UK), EdF (France), and ENEL (Italy) for generation planning studies with particular reference to those tools (or parts of them) that perform a yearly simulation of the generating system operation. Offers a short description of the composition of the 3 generating systems for a better understanding of the different philosophies employed. Comments on the frequency of utilization of the programs and on their main differences. Suggests that since the 3 systems show a tendency towards a more similar mix in the future (e.g. the percentage of hydro power plants will decrease both in the French and in the Italian system while the nuclear and coal base units will increase; all 3 systems will include an increasing share of pumped storage plants) the discussed planning problems will probably become common to the 3 systems. Predicts increasing importance of coal transportation problems for ENEL and EdF organization; a more ...