Energy Technology Data Exchange (ETDEWEB)

Fully coupled, Newton-Krylov algorithms are investigated for solving strongly coupled, nonlinear systems of partial differential equations arising in the field of computational fluid dynamics. Primitive variable forms of the steady incompressible and compressible Navier-Stokes and energy equations that describe the flow of a laminar Newtonian fluid in two-dimensions are specifically considered. Numerical solutions are obtained by first integrating over discrete finite volumes that compose the computational mesh. The resulting system of nonlinear algebraic equations are linearized using Newton`s method. Preconditioned Krylov subspace based iterative algorithms then solve these linear systems on each Newton iteration. Selected Krylov algorithms include the Arnoldi-based Generalized Minimal RESidual (GMRES) algorithm, and the Lanczos-based Conjugate Gradients Squared (CGS), Bi-CGSTAB, and Transpose-Free Quasi-Minimal Residual (TFQMR) algorithms. Both Incomplete ...

Energy Technology Data Exchange (ETDEWEB)

For supersonic plasma flow velocities, instead of the usual shelf-step profile seen for subsonic flow, an overdense bump and cavity is observed. The profile is stable for long times even for moderate power microwaves.

International Nuclear Information System (INIS)

Object: To permit a valve operation test to be periodically made during plant operation without causing variations in plant power by detecting flow control valve defect on the basis of a valve aperture alteration instruction. Structure: Step signals which are equal in absolute value and opposite in sign are coupled to the input side of flow controllers provided on the recycling loops of two or more recycling flow control systems. With these inputs the aperture of the flow control valve on one side is increased (or reduced) while the aperture of the valve on the other side is reduced (or increased). As a result, the recycling flow rate in the loop on one side is increased (or reduced) while that on the other side is reduced (or increased). Whether the valve is normally operating or not is confirmed by checking the recycling flow rate and ...

UK PubMed Central (United Kingdom)

We present the formulation and testing of a mathematical model for the kinetics of homotypic cellular aggregation. The model considers cellular aggregation under no-flow conditions as a two-step process....Full Text Available

Science.gov (United States)

A computational fluid dynamics (CFD) is coupled with a computational structural dynamics (CSD) to simulate the unsteady rotor flow with aeroelasticity effects. An unstructured upwind Navier-Stokes solver was developed for this simulation, with 2nd order time-accurate dual-time stepping method for temporal discretization and low Mach number preconditioning method. For turbulent flows, both the Spalart-Allmaras and Menter's SST model are available. Mesh deformation is achieved through a fast dynamic grid method called Delaunay graph map method for unsteady flow simulation. The rotor blades are modeled as Hodges & Dowell's nonlinear beams coupled flap-lag-torsion. The rotorcraft computational structural dynamics code employs the 15-dof beam finite element formulation for modeling. The structure code was validated by comparing the natural frequencies of a rotor model with UMARC. The ...

International Nuclear Information System (INIS)

Object: To control the average liquid level of each steam generator at a constant level irrespective of the flow rate of sodium thereby to decrease change in the retained amount of sodium and at the same time to improve the load response characteristic. Construction: A method for decreasing to as large an extent as possible a change in the amount of sodium retained in a steam generator due to change in the flow rate, which comprises the steps of detecting the main recirculating flow rate of liquid sodium by the use of a sodium flow rate detector, amplifying the detected flow rate signal depending upon the ratio between the flow rates respectively in a super-heater and a re-heater (distribution ratio), delivering the amplified signal to a function generator which generates a liquid level setting signal for maintaining the respective average ...

Energy Technology Data Exchange (ETDEWEB)

In order to accurately assess the effectiveness of activated charcoal for the removal of radon from flowing air, a literature survey was performed to identify the models and relevant data that were available. It was found that by modifying the mathematical model of equilibrium stage theory used by Strong and Levins, the output rate of an activated charcoal filter exposed to a step function input in the radon rate at time zero with a given carrier gas flow velocity could be predicted. This paper outlines the modifications made to Strong and Levins's model and presents predictions for the filter output from the modified model.

CERN Document Server

Knowledge management is controlling the transfer, distribution, and availability of knowledge. Traditionally, knowledge management processes are predefined; e.g. it is laid out in detail which document template, data structure, system, or work flow steps have to be used in order to manage knowledge. But knowledge management itself is complex. It is simply not possible to predefine the typical flow of work in knowledge intensive processes in advance. So rather than trying to determine the procedures it is more promising to analyze which factors can be used in order to control the outcome of t

Energy Technology Data Exchange (ETDEWEB)

The purpose of this report is to determine if it is feasible to utilize the hot exhaust gas discharged from gas turbines in direct applications. This report illustrates the technical feasibility and economic viability of using gas turbines in drying applications. The size of turbines in this investigation ranges from 2 MW to 10 MW. In addition, an implementation strategy has been developed to employ this new system. The method used to structure the scope of this undertaking is as follows: Step 1. Collecting information by contacting dryer manufacturer and companies drying different products. Information was also gathered by literature studies and the internet. Thomas register is a great tool when it comes to company and market searches. Step 2. Looking into if it is technically possible to use the exhaust gas directly into dryers. The parameters needed for these calculations were gathered in step 1, and some of the more ...

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 layer. The present ...

Energy Technology Data Exchange (ETDEWEB)

Particle simulation studies of collisionless driven reconnection in an open system are presented. Collisionless reconnection evolves in two steps in accordance with the formation of two current layers, i.e., an ion current layer in the early ion phase and an electron current layer in the late electron phase. After the electron current layer is formed inside the ion current layer, the system relaxes gradually to a steady state when convergent plasma flow is driven by an external electric field with a narrow input window. On the other hand, when the convergent plasma flow is driven from the wide input window, magnetic reconnection takes place in an intermittent manner, due to the frequent formation of magnetic islands in the vicinity of neutral sheet. (author)

Energy Technology Data Exchange (ETDEWEB)

Sufficient discussion of the elements of the leasing and permitting programs is included to place the information developed in proper context. A table and process flow diagram developed previously which outline the steps in the non-competitive leasing process, is reprinted. Computer printout profiles are presented on 195 identifiable areas in the following states: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. Sufficient information on the boundaries of these areas is contained in the report to permit identification of their general location on any map of the appropriate state which shows township and range locations.

Energy Technology Data Exchange (ETDEWEB)

In this work the authors study the stabilization point of a lifted, reacting jet of nitrogen diluted methane in co-flowing air. The jet flow is acoustically forced so as to organize the large scale vortical structures. The validation of the numerical results is possible through a concurrent experimental investigation of a similar planar jet. The use of an acoustically forced planar jet allows for significant savings by the restriction of the computation to two dimensions; the model is otherwise applicable in three dimensions. The authors based their study on the following parameters, which are derived from the experimental setup: a jet width of 1.16 cm, a mean jet velocity of 0.8 m/s, and a coflow velocity of 0.1 m/s. The acoustical forcing is studied at frequencies of 7.5 MHz and 90 MHz, which have been established experimentally as being characteristic of two broad behavioral modes. The authors restrict themselves to five species and the ...

British Library Electronic Table of Contents (United Kingdom)

The pentenary compound semiconductor Cu(In,Ga)(Se,S)2 is one of the most attractive materials for high-efficiency solar cells due to its tunable band gap to match well the solar spectrum. In this study, semiconducting Cu(In,Ga)(Se,S)2 thin films were prepared by a classical two-step growth process, which involves the selenization and/or sulfurization of In/Cu?Ga precursor. During the precursor formation step metallic In/Cu?Ga alloys were deposited onto the Mo-coated soda-lime glass substrates by DC magnetron sputter process. The respective precursors were subsequently reacted with H2Se and/or H2S gasses, at elevated temperatures. By optimizing the selenization parameters, such as the gas concentrations, reaction time, reaction temperature, and the flow of H2Se and H2S, high quality, single...

International Nuclear Information System (INIS)

The behavior of lead in the graphite furnace during the individual steps of the temperature program was investigated by means of "2"0"3Pb as a radiotracer. The matrix systems include HCl and HNO_3 solutions, 1% NaCl solution, blood, serum, urine, and the solid samples bovine liver and orchard leaves. Without matrix modificaton, a pyrolysis temperature of up to 500"0C can be used for all samples. Significant stabilization effects can be achieved in the preatomization steps by using NH_4H_2PO_4 and ammonia as matrix modifiers and by addition of hydrogen to the flowing argon gas. It was found that the use of a L'vov platform also helps to eliminate the matrix effects. With respect to lead stabilization and elimination of matrix effects, optimum experimental conditions are achieved by simultaneous use of a L'vov platform and NH_4H_2PO_4 as the matrix modifier. 34 references, 5 figures, 1 table.

Energy Technology Data Exchange (ETDEWEB)

Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and ...

Energy Technology Data Exchange (ETDEWEB)

Recent research has shown that biologically inspired approaches to materials synthesis and self-assembly, hold promise of unprecedented atomic level control of structure and interfaces. In particular, the use of organic molecules to control the production of inorganic technological materials has the potential for controlling grain structure to enhance material strength; controlling facet expression for enhanced catalytic activity; and controlling the shape of nanostructured materials to optimize optical, electrical and magnetic properties. In this work, we use organic molecules to modify silver crystal shapes towards understanding the metal-organic interactions that lead to nanoparticle shape control. Using in situ electrochemical AFM (EC-AFM) as an in situ probe, we study the influence of a cationic surfactant cetyltrimethylamminobromide (CTAB) on Ag growth during electrochemical deposition on Ag(100). The results show that the organic surfactant promotes the growth of ...

Energy Technology Data Exchange (ETDEWEB)

The tri-n-butyl phosphate(TBP) extraction behavior of tritium was studied to support the evaluation of tritium confinement in the Purex process. The tritium distribution ratio in the system of U - 30% TBP/n-dodecane(nDD) - HNO[sub 3] [minus]H[sub 2]O was measured in batch-wise experiments. The tritium decontamination factor in a tritium scrubbing step was measured in chemical flow sheet experiments using a 6 stage mixer-settler having an internal recycle system of aqueous solution in each stage. Tritium was mainly extracted in the forms of water and nitric acid in the system. Less than 1% of the amount of tritium in the organic phase was fixed in the degradation products of the solvent. A tritium decontamination factor of about 500 in the tritium scrubbing step was obtained under the conditions of about 85 g-U/dm[sup 3] of uranium concentration in the irradiated solvent(30% TBP/nDD), 3 M nitric acid in the tritium scrubbing ...

International Nuclear Information System (INIS)

Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-? model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the experimental data than that of the case without radiation effect.

Energy Technology Data Exchange (ETDEWEB)

During the last fifteen years a variety of instruments and transducers, such as voltage plugs, power transducers, flow and pressure transducers, recorders and tensometers, have been developed for underground use in measuring the performance and technical parameters of prototype machines. The equipment, until recently, has been in a portable form and was found useful by the industry generally, in fault finding and trouble-shooting exercises and in commissioning procedures performed by small teams on a call-out basis. Over the last five years the test equipment has been adapted and the techniques modified to suit individual colliery-based operations with more permanent machine mounted and built-in transducers. At the moment these techniques operate within the framework of a statutory planned preventive maintenance scheme for each mine. This paper discusses the merits of changing from preventive maintenance to condition-based maintenance and the practical ...

International Nuclear Information System (INIS)

A Process for yellow cake production from local Euxenite was developed in Bench Scale by using sulphuric acid digestion with simultaneously ion-exchange and solvent extraction purification steps. Uranium was then precipitated as uranium diuranate by ammonia solution. Equipment used in this process includes : digestion vessels, columnar ion-exchange, solvent extraction and precipitation units Ore feed to the process could be adjusted up to 2 kilogram per day (8 hours operation) with yellow cake product purity meet the requirement of Usaec standard of about 10-50 gram per day. Included in this experiment are the leaching characteristics of the ore, the design and construction of continuous columnar 4-cycle ion exchange unit, determination of the extraction and stripping stages of a gravity flow mixer-settler and the design and construction of continuous yellow cake precipitation unit with large grain size and high density product

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy selected caustic-side solvent extraction (CSSX) as the preferred cesium-removal technology for SRS high-level waste. In the pretreatment step of the CSSX flowsheet, the incoming salt solution, which contains entrained sludge, is contacted with MST to adsorb strontium and selected actinides. An alternative approach replaces MST with the addition of sodium permanganate, strontium nitrate, and hydrogen peroxide. The pretreatment operation then filters the resulting slurry to remove the sludge and MST or manganese oxide and strontium carbonate solids. The filtrate receives further treatment in the solvent extraction system. SRTC personnel coordinated tests using a SpinTek rotary microfilter at the vendor location in FY01. These tests demonstrated a significant improvement - 2.5 to 6 times increase - in performance relative to the conventional cross-flow filter units. Rotary microfilter testing used a filter disk with ...

Energy Technology Data Exchange (ETDEWEB)

The main purpose of this study is to develop a thermal hydraulic auditing code for the CANDU reactor, modifying the model of existing PWR auditing tool , i.e. RELAP5/MOD3. This scope of project is a fourth step of the whole project, applying the RELAP5/MOD3/CANDU+ version for the real CANDU plant LOCA Analysis and D2O leakage incident. There are three main models under investigation, i.e. Moody critical flow model, flow regime model of horizontal CANDU bundle, and fuel element heatup model when the stratification occurs, especially when CANDU LOCA is tested. Also, for Wolsung unit 1 D2O leakage incident analysis, the plant behavior is predicted with the newly developed version for the first 1000 seconds after onset of the incident, with the main interest aiming for system pressure, level control system, and thermal hydraulic transient behavior of the secondary system. The model applied for this particular application ...

International Nuclear Information System (INIS)

In this article carbon co-implantation and step-by-step thermal treatments of shallow p"+-n-junctions formation were used with the purpose of extended defect suppression and reduction of boron transient enhanced diffusion. A substantial improvement of the structural and electrical parameters of shallow p"+-n-junctions has been achieved by using the additional carbon implantation and step-by-step thermal treatments. (authors)

Energy Technology Data Exchange (ETDEWEB)

The use of aqueous methyldiethanolamine (MDEA) for selective removal of hydrogen sulfide from acid gas streams has been studied in a 2 inch column packed with 1/4 inch ceramic Intalox saddles. The column was operated in a counter-current, steady state fashion. The feed gas composition varied between 1 and 5 mole % hydrogen sulfide and between 0 and 50 mole % carbon dioxide. In order to assist the development of packed column absorption models, the rate at which pure carbon dioxide absorbs into 2 M MDEA was measured as a function of pressure, liquid flow rate and packed bed length. The importance of end effects was carefully evaluated. In addition, draining and tracer methods were used to estimate the amount of static holdup present in the column. Using classical draining methods, as much as 50 % of the total holdup was found to be static. However, according to the step decrease in tracer method, less than 5 % of the total holdup was static. ...

Energy Technology Data Exchange (ETDEWEB)

A fast and simple flow-through optosensor was designed and characterized for the direct screening of four tetracycline (TCC) antibiotics (tetracycline, oxytetracycline, chlortetracycline and doxycycline) in water and bovine milk samples. The proposed optosensor provides rapid binary yes/no overall responses, being appropriate for the screening of this family of antibiotics above or below a pre-set concentration threshold. The experimental set-up is based on a flow-injection manifold coupled on-line to a phosphorescence detector. Aliquots of the samples are pretreated with Eu(III) to form room temperature phosphorescent metal chelates and injected in the flow manifold. Those chelates are then on-line retained on a conventional flow-cell (packed with polymeric Amberlite XAD-4 particles) which is placed inside the cell holder of the phosphorimeter. After the emission is registered, the antibiotic-metal ...

Energy Technology Data Exchange (ETDEWEB)

Combustion in a ceramic tube produces a nearly discontinuous change in temperature of the premixed fuel and air at the flame front, from room temperature up to the adiabatic flame temperature ([approximately]2,100 K). The upstream Reynolds number for a stable flame in a 9.5-mm tube is in the range of 3,000-6,000, corresponding to turbulent flow. Owing to property changes that accompany the severe increase in temperature at the flame front, the downstream Reynolds number is reduced below the transitional value ([approximately]2,100); consequently the turbulence decays while the velocity profile approaches the parabolic one characteristic of laminar flow. A previous study of ours revealed that, far downstream from the flame front, the turbulent energy decayed exponentially with downstream distance. This paper examines the asymptotic behavior of the k-[epsilon] model and compares the results to that for two-dimensional (axisymmetric) disturbances ...

Energy Technology Data Exchange (ETDEWEB)

As a first step an attempt was made to integrate a personnel information facility into a system for optimising materials flow. The two systems developed did not reach a workable stage because the synthetic language would have required an input on the part of the personnel operating the system beyond what could reasonably be expected. The research in the second stage consisted in developing and testing a module with which language storage services could be built up on the basis of digitalised speech and controlled via the in-house telephone network. In language storage services users may feed in data or interrogate. Services of this kind can readily be integrated into available telephone installations working on the pulse selection principle. The low cost of the hardware involved means the system can be built up with modest investment while offering high effectiveness. 6 refs., 2 figs.

International Nuclear Information System (INIS)

The preparation of wood-plastic combinations (WPC) using combined methods for curing intermediate products and final products is described. In the first step, impregnated wood was irradiated using doses of 1 to 10 kGy in the presence of chemical initiators of polymerization. Thereafter, curing of this partly cured impregnating mixture was accomplished in the wood at elevated temperatures with the aid of chemical initiators of polymerization. Impregnation mixtures based on unsaturated polyester resins and methyl methacrylate, and the wood species European Beech (Fagus silvatica) and Black Alder (Alnus glutinosa) were used. The results indicate that this method of preparing WPC allows substantially lower radiation doses to be used, i.e., doses in the range of 1 to 2.5 kGy. These doses gelatinate the impregnation mixture in the wood so that the subsequent curing by chemical polymerization initiators proceeds without the impregnation mixture ...

Science.gov (United States)

The objective of the current research in coal liquefaction is to produce a synthetic crude from coal at a cost lower than $30.00 per barrel (Task A). A second objective is to produce a fuel which is low in aromatics, yet of sufficiently high octane number for use in the gasoline-burning transportation vehicles of today. To meet this second objective, research was proposed for conversion of the highly-aromatic liquid product from coal conversion to a product high in isoparaffins, which compounds in the gasoline range exhibit a high octane number (Task B). Experimental coal liquefaction studies conducted in a batch microreactor in the laboratory have demonstrated potential for high conversions of coal to liquids with low yields of hydrocarbon (HC) gases, hence small consumption of hydrogen in the primary liquefaction step. Ratios of liquids/HC gases as high as 30/1, at liquid yields as high as 82% of the coal by weight, have been achieved. The principal objective of ...

Energy Technology Data Exchange (ETDEWEB)

To carry out studies on the radon behavior under controlled and stable conditions it was designed and constructed a system that consists of two parts: a container of mineral rich in Uranium and an experimentation chamber with radon united one to the other one by a step valve. The container of uranium mineral approximately contains 800 gr of uranium with a law of 0.28%; the radon gas emanated by the mineral is contained tightly by the container. When the valve opens up the radon gas it spreads to the radon experimental chamber; this contains 3 accesses that allow to install different types of detectors. The versatility of the system is exemplified with two experiments: 1. With the radon experimental chamber and an associated spectroscopic system, the radon and two of its decay products are identified. 2. The design of the system allows to couple the mineral container to other experimental geometries to demonstrate this fact it was coupled and proved a new automatic ...

Energy Technology Data Exchange (ETDEWEB)

This project is part of PETC`s Advanced Power Systems Program, whose mission is to accelerate the commercialization of affordable, high- efficiency, low emission, coal-fueled electric generating technologies. A process concept - Clear Liquor Scrubbing with Anhydrite Production - was proposed and accepted by PETC as a Phase I project in its Mega-PRDA program. the project integrated three process operations - chloride control upstream of the flue gas desulfurization (FGD) system, a clear liquor process for enhanced SO{sub 2} removal performance, and production of anhydrite (anhydrous calcium sulfate) rather than calcium sulfite or gypsum (calcium sulfate dihydrate). The first step in the project was to perform batch and flow-through experiments in the laboratory to confirm theoretical calculations and preliminary laboratory results concerning anhydrite formation, these laboratory experiments were designed to prove that anhydrite can be produced ...

Energy Technology Data Exchange (ETDEWEB)

The fixed bed pilot plant, the catalyst testing procedure, and the calculations for conversion and selectivities were previously described in the technical progress report covering the period of 3/16/88 to 6/16/88 for Contract DE-AC22-87PC79812. Conversions and hydrocarbon selectivities were calculated using data from an on-line gas chromatography (GC) analyzer. Alcohol selectivities were calculated using data from an on-line boiling point GC analyzer which analyzed the liquid product. The catalysts were prepared via the steps of impregnation, calcination, and reduction on a special Y-zeolite-derived support. The impregnation step consisted of evaporation of metal salts on to the support from an aqueous solution. For one catalyst (No. 6531-188) the metal salts were evaporated on to the support from a reverse micelle solution containing the metal salts. All the catalysts were calcined for four hours at 450{degree}C. The calcined catalysts were ...

Science.gov (United States)

... 65th AGARD Fluid Dynamics Symposium, Madrid, Spain, October ... of research programs on flow control ... separation, and delta wing flows formed the ...

Science.gov (United States)

impflrtant to the understanding of complex vortical flows. ... tions like the slender wing, flow separations are controlled in the s,. ...... 10, AGARD LS-121, Dec. ...

CERN Document Server

Industrial-process control valves Part2 : Flow capacity Section Four : Inherent flow characteristics and rangeability

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a nitrogen oxides decreasing combustion method which comprises: a first step of mixing a fuel and air with each other; a second step of bringing the mixture obtained in the first step into contact with a packed catalyst such that only catalytic combustion occurs; and a third step of adding a fresh supply of the fuel to a stream obtained from the second step to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion. The temperature of the packed catalyst is lower than the ignition temperature of the mixture and the adiabatic flame temperature of the mixed gas is lower than a temperature at which the nitrogen oxides occur.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A flow pattern or flow regime is the characteristics spatial distribution of the phases of fluid in a duct. Since heat transfer and pressure drop are dependent on the characteristic distribution of the phases, it is necessary to describe flow patterns in an appropriate manner so that a hydrodynamic or heat transfer theory applicable to that pattern can be chosen. The objective of the present analysis is to create a flow regime map based on physical modeling of vapor/liquid interaction phenomena in a microgravity environment. In the present work, four basic flow patterns are defined: dispersed flow, stratified flow, slug flow, and annular flow. Fluid properties, liquid and vapor flow rates, and pipe size were chosen as the principal parameters. It is assumed that a transition from ...

Energy Technology Data Exchange (ETDEWEB)

Leakage of CO{sub 2} and displaced brine from geologic carbon sequestration (GCS) sites into potable groundwater or to the near-surface environment is a primary concern for safety and effectiveness of GCS. The focus of this study is on the estimation of the probability of CO{sub 2} leakage along conduits such as faults and fractures. This probability is controlled by (1) the probability that the CO{sub 2} plume encounters a conductive fault that could serve as a conduit for CO{sub 2} to leak through the sealing formation, and (2) the probability that the conductive fault(s) intersected by the CO{sub 2} plume are connected to other conductive faults in such a way that a connected flow path is formed to allow CO{sub 2} to leak to environmental resources that may be impacted by leakage. This work is designed to fit into the certification framework for geological CO{sub 2} storage, which represents vulnerable resources such as potable groundwater, health and safety, ...

Energy Technology Data Exchange (ETDEWEB)

Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

International Nuclear Information System (INIS)

Background: High-resolution computed tomography is the image procedure of choice in the evaluation of interstitial lung disease. Multidetector-row computed tomography provides the possibility of simultaneous reconstruction of thin and thick slices from the same raw data, acquired from one single series. Thus, it may be tempting to exclude the step-and-shoot series. Purpose: To compare high-resolution computed tomography (HRCT step-and-shoot) from single-slice CT (SSCT) and 16-channel multidetector CT (MDCT) in terms of visibility and motion artifacts, and to investigate whether thin images reconstructed from helical MDCT are equal to or better than conventional HRCT by SSCT in terms of visibility and motion artifacts. Material and Methods: 20 patients underwent HRCT step-and-shoot by SSCT (SSCT step-and-shoot) and MDCT (MDCT step-and-shoot), and a helical MDCT acquisition (MDCT ...

Science.gov (United States)

... percent by interbasin ground-water flow into the Hueco Bolson, and 2 percent by flow into creeks and ... ...

Science.gov (United States)

A method for calculating flow through an airfoil cascade drawn on a surface of revolution is discussed. The three-dimensional flow was assumed to be represented by part-channels of varying width. The basic equations are the equation of continuity and the ...

Science.gov (United States)

... In: Separated Flows, AGARD CP No. ... on thin wings in two-dimensional incompressible flow. ... fields in the region of separating and reattaching flows. ...

Science.gov (United States)

... including those with rear separation, ... flows ibout airfoils." AIAA Paper 'Jo 97-0419, 1987). ... "Effects of streamline curvature on turbulent flow." AGARD ...

Science.gov (United States)

Surface pressure measurements at mid span indicate that flow separation begins near ..... Turbomachinery Flows, AGARD Propulsion Energetics Panel, 1998. ...

International Nuclear Information System (INIS)

According to the present concept, the low and intermediate level wastes generated during the Cernavoda NPP operation will be disposed in a near surface repository. The Saligny site, placed in the NPP protected area, has been proposed for their disposal. Geologically, the main components of this site are the quaternary loess, the Precambrian and Pre-quaternary clays, the Eocene and Barremian limestone. Hydrologically, the site can be divided into a vadose zone down to 45-50 m and three distinct aquifers, two of them in the limestone beds and the third in the lenses of sand and limestone existing in the pre-quaternary clay layer. A large research program for site characterization was initiated in 1996. At present, the site characteristics requested for safety analysis have been experimentally measured on soil samples or calculated by different computer programs. Hundreds of experimental values of the density, porosity, hydraulic conductivity, soil-water retention, moisture content or ...

Science.gov (United States)

A simplified two step thermal analysis method has been develop to evaluate (1) the mean temperature of the CANDU fuel bundles within a fuel basket in a given spent fuel dry storage canister by HEATING5 code with additional input data and heat transfer correlations in the step-1 analysis and (2) the maximum fuel rod temperature within a CANDU 37-element fuel bundle by MAXROT code developed here for step-2 analysis. In addition, the results of sample analysis is performed to examine the parametric effects of the site-specific ambient conditions on the maximum fuel temperature within a canister are presented. The comparison between the results of step-1 analysis and the mock-up test, in particular, is quite satisfactory. In essence, the two-step thermal analysis method proposed here is a code package that used the HEATING5 and MAXROT codes, respectively, for step-1 ...

International Nuclear Information System (INIS)

... charge-exchange reactions dwba finite-range interactions helium 3 reactions

Science.gov (United States)

No abstract prepared.

Science.gov (United States)

... Tactical Electronic Warfare Division (Code 5700) Visualization Laboratory Transportable step frequency radar Vehicle development laboratory ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A lock out assembly for a circuit breaker which consists of a generally step-shaped unitary base with an aperture in the small portion of the step-shaped base and a roughly S shaped retaining pin which loops through the large portion of the step-shaped base. The lock out assembly is adapted to fit over a circuit breaker with the handle switch projecting through the aperture, and the retaining pin projecting into an opening of the handle switch, preventing removal.

Science.gov (United States)

Not Available

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

PMID:476294

Science.gov (United States)

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

Science.gov (United States)

... Agard Report 272,1960 ... and reattached subsonic turbulent flows obtained downstream ... of flow separations due to deflected control surfaces. ...

Science.gov (United States)

... The fundamental problem of diaphragm rupture was studied experimentally to determine the effects on an expanding flow in an evacuated tube. ...

International Nuclear Information System (INIS)

Visualizations by real-time neutron radiography are demonstrated of various flow patterns of nitrogen gas-water two-phase flow in a stainless-steel tube, water inverted annular flow in a stainless-steel tube, flashing flow in an aluminium nozzle and fluidized bed in aluminium tube and vessels. Photographs every 1/60 s are presented by an image processing method to show the dynamic behaviours of the various flow patterns. It is shown that this visualization method can be applied efficiently to multiphase flow researches and will be applicable to multiphase flows in industrial machines. (author).

Energy Technology Data Exchange (ETDEWEB)

The main objective of this dissertation is to build a numerical 3D geological model of a turbidite reservoir using well and seismic data. For the, the first step was to elaborate a depositional model using a high-resolution genetic stratigraphy approach. Simultaneously, the stratigraphic inversion over the seismic data resulted in an optimal acoustic impedance model. Both models, were used to build, by geostatistical methods, a 3-D geological model, which represents the spatial distribution of the reservoir facies. The studied case is the late Cretaceous Namorado turbidite system in the Campos basin, which is the reservoir of the Namorado oil field, located 80 km from the Brazilian coast, under a bathymetry between 110 and 250 m. The reservoir is a turbidite succession with 90 to 180 m thickness. It is composed by sand-supported conglomerates, matrix-supported conglomerate, massive sandstones, shales, marls and limestones. Four lithotypes characterise the main ...

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A three-dimensional, three-phase, multiple-component numerical simulator was developed to investigate transport and growth of microorganisms in porous media and the impacts of microbial activities on oil recovery. The microbial activities modeled in this study included: (1) growth, retention, chemotaxis, and end product inhibition of growth, (2) the formation of metabolic products, and (3) the consumption of nutrients. Major mechanisms for microbial enhanced oil recovery (MEOR) processes were modeled as follows: (1) improvement in sweep efficiency of a displacement process due to in situ plugging of highly-permeable production zones by cell mass or due to improved mobility control achieved by increasing the viscosity of the displacing fluid with a biopolymer, and (2) solubilization and mobilization of residual oil in porous media due to the reduction of the interfacial tension between oleic and aqueous phases by the production of a biosurfactant. The numerical solutions for ...

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This paper is dedicated to the numerical study of natural ventilation in a room through a large external opening using the CFD code Fluent. Bidimensional numerical simulations are performed for wind speeds up to 5.55 m-s{sup -1} (20 km-h{sup -1}). We propose a two-step solution procedure with grid refinement. When combined with appropriate thermal boundary conditions, this technique appears very efficient at limiting local convergence problems. Through an analysis of the flow pattern in the cavity, we qualitatively explain those results and define a critical Archimedes number. Calculated air change rates are compared to values deduced from empirical correlations of the literature. Agreement is in general poor, which can be explained by the differences between the conditions of our simulations and those of the experiments that lead to those correlations. However, from our simulations, we derived very clear correlations between the air change ...

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Computation of effective flow properties of fluids in porous media based on three dimensional (3D) pore structure information has become more successful in the last few years, due to both improvements in the input data and the network models. Computed X-ray microtomography has been successful in 3D pore imaging at micron scale, which is adequate for many sandstones. For other rocks of economic interest, such as chalk and diatomite, submicron resolution is needed in order to resolve the 3D-pore structure. To achieve submicron resolution, a new method of sample serial sectioning and imaging using Focused Ion Beam (FIB) technology has been developed and 3D pore images of the pore system for diatomite and chalk have been obtained. FIB was used in the milling of layers as wide as 50 micrometers and as thin as 100 nanometers by sputtering of atoms from the sample surface. The focused ion beam, consisting of gallium ions (Ga+) accelerated by potentials of up to 30 kV and ...

International Nuclear Information System (INIS)

At the Forschungszentrum Karlsruhe the HGF Strategy Fund project entitled 'Innovative Technology to Reduce Radiotoxicity' is performed which delivers an essential scientific contribution to the application oriented fundamental research for Accelerator Driven Systems (ADS). The addressed topics are in the areas of heavy liquid metal technology, thermalhydraulics and materials / corrosion. An ADS consists of three main components: an proton accelerator, a spallation target and a subcritical blanket. The strategic objective of an ADS is the transmutation of long-lived radioactive waste (plutonium, minor actinides and long-lived fission products) into short-lived isotopes or stable elements, thus closing the fuel cycle. The objective of one task of the HGF Strategy Fund Project is the numerical calculation of a closed spallation target module. In a consequent next step such a spallation target can be experimentally investigated at IKET and the numerical results can be ...

International Nuclear Information System (INIS)

Full text of publication follows: Low activation ferritic/martensitic steels are receiving a high priority in the European long term materials research. Although extensively investigated, the available experimental data do not cover all required parameter ranges and cannot unambiguously be used to produce hardening/embrittlement trend curves. Therefore, the main objective of this work is to provide a physically-based engineering model offering a rational to experimental observations. From the literature, experimental data were selected to establish a database that mainly consists of 8 to 9Cr-steels irradiated in the range of 50 to 600 deg. C up to 30 dpa and with a He-content up to 5000 appm. The database includes neutron and proton irradiations, He-implanted as well as B- and Ni-doped steels. Because of the difficulty of interpretation inherent to the Charpy impact test, only tensile data were considered. The difficulty stems from the large range of specimen sizes that are used, the ...

Energy Technology Data Exchange (ETDEWEB)

A Real-Time Neutron Radiography (RTNR) system is used to determine two-phase flow parameters for a horizontal co-current two-phase flow channel with a CANDU-type 37 rod bundle. Image processing techniques are applied to visualize the two-phase flow, and to determine flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution. The experimentally determined flow regime map disagrees with existing flow regime models developed for the CANDU-type rod bundles. A new flow regime is observed and designated Large Amplitude Stratified Wavy flow. The results show that the LASW flow regime may be due to a combination of undeveloped flow phenomena, boundary conditions, and circumferential cross flow occurring in the bundle. The ...

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system is used to determine two-phase flow parameters for a horizontal co-current two-phase flow channel with a CANDU-type 37 rod bundle. Image processing techniques are applied to visualize the two-phase flow, and to determine flow regime, cross-sectional averaged void fraction, time averaged void fraction, and void distribution. The experimentally determined flow regime map disagrees with existing flow regime models developed for the CANDU-type rod bundles. A new flow regime is observed and designated Large Amplitude Stratified Wavy flow. The results show that the LASW flow regime may be due to a combination of undeveloped flow phenomena, boundary conditions, and circumferential cross flow occurring in the bundle. The ...

Energy Technology Data Exchange (ETDEWEB)

Applications, techniques, instrumentation, and interpretation of flow visualization are discussed. Methods of using flow visualization for the examination of combustion in furnaces, heat transfer with heat exchangers, and in fluid engines are explored, along with flow visualization in food processing, steel-casting, and process engineering. Further attention is given to pipe and channel flow, flow separation in laminar flow and around oscillating airfoils, wakes and vortices, supersonic flow and shock waves, and stratified flow and oceanography. The visualization of boundary layers is considered for various conditions, and applications for multiphase flow, rheology, and medical problems are detailed. Oil film, dry-surface coating, chemical, fluorescent, and minituft methods are presented, as well as ...

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A two-phase flow regime map is developed experimentally and theoretically for a vertical hexagonal flow channel with and without a 36-finned rod hexagonal bundle. This type of flow channel is of interest to MAPLE-type nuclear research reactors. The flow regime maps are determined by visual observations and observation of waveforms shown by a capacitance-type void fraction meter. The experimental results show that the inclusion of the finned hexagonal bundle shifts the flow regime transition boundaries toward higher water flow rates. Existing flow regime maps based on pipe flow require slight modifications when applied to the hexagonal flow channel with and without a MAPLE-type finned hexagonal bundle. The proposed theoretical model agrees well with experimental results.

International Nuclear Information System (INIS)

Many pump reliability problems in the Nuclear Power Plants (NPPs) are being attributed to the operation of the pump at flow rates well below its best efficiency point(BEP). Generally, the manufacturer and the user try to avert such problems by specifying a minimum flow, below which the pump should not be operated. Pump minimum flow usually involves two considerations. The first consideration is normally termed the 'thermal minimum flow', which is that flow required to prevent the fluid inside the pump from reaching saturation conditions. The other consideration is often referred to as 'mechanical minimum flow', which is that flow required to prevent mechanical damage. However, the criteria for specifying such a minimum flow are not clearly understood by all parties concerned. Also various factor and information for ...

International Nuclear Information System (INIS)

This paper describes the study of particles' dispersion in an isotropic turbulent flow. The particle's motion and the turbulent flow characteristics are calculated independently. While the particles' displacement is computed by the author's code, the flow is simulated with a commercial code : PowerFLOW. The particles and the flow are coupled through the relative velocity component of the aerodynamic force. When the simulated flow is turbulent, a turbulence regeneration model is used in order to get the flow instantaneous velocity. Validation of the method is done by comparing the particles' dispersion obtained with experimental results from literature and with the results calculated by FLUENT. Good accordance is found between numerical studies and experimental results. However, comparison between results of PowerFLOW ...

International Nuclear Information System (INIS)

In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).

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

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The stability-enchancing two-step (SETS) method has been used successfully in the Transient Reactor Analysis Code (TRAC) for several years. The method consists of a basic semi-implicit step combined with a stabilizer step that, taken together, eliminate the material Courant stability limit associated with standard semi-implicit numerical methods. This approach toward stability requires significantly fewer computational operations than a fully implicit method, but currently maintains the first-order accuracy in space and time of its semi-implicit predecessors.

British Library Electronic Table of Contents (United Kingdom)

In this study, a two-step process was developed to produce biodiesel from Calophyllum inophyllum oil. Pre-treatment with phosphoric acid modified b-zeolite in acid catalyzed esterification process preceded by transesterification which was done using conventional alkali catalyst potassium hydroxide (KOH). The objective of this study is to investigate the relationship between the reaction temperatures, reaction time and methanol to oil molar ratio in the pre-treatment step. Central Composite Design (CCD) and Response Surface Methodology (RSM) were utilized to determine the best operating condition for the pre-treatment step. Biodiesel produced by this process was tested for its fuel properties.

Science.gov (United States)

... UNCLASSIFIED The 60 Minute Network Security Guide ... 15. SUBJECT TERMS IATAC Collection; information security; network security 16. ...

CERN Document Server

We have developed a simulation code with the techniques which enhance both spatial and time resolution of the PM method for which the spatial resolution is restricted by the spacing of structured mesh. The adaptive mesh refinement (AMR) technique subdivides the cells which satisfy the refinement criterion recursively. The hierarchical meshes are maintained by the special data structure and are modified in accordance with the change of particle distribution. In general, as the resolution of the simulation increases, its time step must be shortened and more computational time is required to complete the simulation. Since the AMR enhances the spatial resolution locally, we reduce the time step locally also, instead of shortening it globally. For this purpose we used a technique of hierarchical time steps (HTS) which changes the time step, from particle to particle, depending on the size of the cell in ...

Science.gov (United States)

... the area covered by the point-count grid, stopping approximately every 100 m, stepping away from the vehicle, and scanning with binoculars for mountain plovers. Once ... ...

Medline Plus

... very difficult to help get better and to rehabilitate and sometimes even need surgery. 00:04:21 ... step of treatment, from our standpoint, is to rehabilitate, to strengthen the shoulder. And the real key ...

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The following subjects are dealt with: physics of indoor air flow, flow in individual rooms, exchange of air and pollution between individual building zones and with the outside world, thermal coupling with the building shell, thermal comfort and air quality, evaluation of the ventilation. figs., tabs., refs.

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The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow ...

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Traditional two-phase flow-regime criteria based on the gas and liquid superficial velocities may not be suitable to the analyses of rapid transient or entrance flows by the two-fluid model. Under these conditions, it is postulated that direct geometrical parameters such as the void fraction are conceptually simpler and therefore more reliable parameters to be used in flow-regime criteria than the traditional parameters. From this point of view, new flow-regime criteria for upward gas-liquid flow in vertical tubes have been developed considering the mechanisms of flow-regime transitions. These new criteria can be compared to existing criteria and experimental data under steady-state and fully developed flow conditions by using relative velocity correlations. The criteria showed reasonable agreements with the existing data for atmospheric ...

UK PubMed Central (United Kingdom)

Instantaneous cross sectional flow velocity profiles from early mitral flow in 10 healthy men were constructed by time interpolation of the velocity data from each point in sequentially delayed two...Full Text Available

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The Tevatron accelerator at Fermilab incorporates long two-phase helium passages. During magnet design, the generalized flow map of Baker was used to predict homogeneous flow. Longer than expected magnet time constants led to this investigation. The importance of predicting the flow regime has been amplified with the advent of non-horizontal accelerator designs. A test setup was constructed at Fermilab to investigate two-phase helium flow regimes for conditions practical in accelerator designs. The setup consisted of a standard Tevatron satellite refrigerator, subcooling dewar, heater, 35 m long transfer line, and a specialized end box. A knife blade on the midplane of the transfer line diverted the flow from the upper and lower halves of the pipe to separate vessels in the end box. The amount of liquid above and below the plane was measured at various total mass ...

British Library Electronic Table of Contents (United Kingdom)

The details of pulsating stochastic flows accompanying the interaction of a microwave filament (regarded as a heated rarefied channel) and an aerodynamic body in supersonic flow are examined numerically using the Euler equations. Symmetrical and asymmetrical filament locations relative to the aerodynamic body are considered. The flowfields are characterized by large scale pulsations and small scale stochastic fluctuations. The mechanisms of the formation of these flow structures are discussed. Two qualitatively different kinds of flowfields are observed depending on the magnitude of the filament radius, with domination of the pulsations of flow parameters or stochastic phenomena. Flow instabilities inherent to the problems under interest are described. The problems are considered in both p...

International Nuclear Information System (INIS)

In FY 1984 three specific tasks which are all related to not-well-understood two-phase phenomena of importance to LWR accidents have been identified under the program. These three tasks are: (1) inverted annular flow experiments and modeling; (2) hot leg U-bend two-phase flow simulation study; and (3) development and evaluation of two-phase flow scaling criteria. Some of the important results obtained under Tasks (1) and (2) are reported in this paper.

Science.gov (United States)

This paper deals with a mixed convection water flow in a horizontal rectangular duct, uniformly heated from one lateral vertical wall and thermally insulated elsewhere. The supplied heat flux induces a secondary flow, which structure is constituted of one longitudinal roll in the considered aspect ratio (? = 1.9), embedded into a return flow of possibly large stream wise extension (up to twenty channel heights). Such situation induces helicoidal trajectories for the fluid flow particles, which contributes to a heat transfer enhancement compared to purely forced convection flow.

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The aim with this project sponsored by Energimyndigheten is to develop a method for calculations of grate boilers fueled by bark. This report describes this project, 'Evaluation Method for Grate Combustion' (EMGC). CFD codes is an engineering tool applicable in the area of the over-grate section called the furnace. This part of the boiler is easy to model for an experienced CFD code user and the results are usually quite satisfactory for evaluating the combustion process in general. Various gas phases reactions and related combustion processes over the burning bed can be simulated including air staging, fuel staging and SNCR. However the simulation needs information of amount and properties of the burning bed products, entering the furnace. The simulation of the in-furnace processes without this information is often just a numerical speculation. A predictive mathematical model based on physical and chemical data for the grate and fuel bed would solve this problem. ...

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A visual study of film boiling is carried out to determine the flow regime transition in the post-CHF region. An idealized inverted annular flow is obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas velocities are 0.05-0.5 and 0.03-8.2 m s/sup -1/. Nitrogen and helium are used in the study. For the present configuration, there are four flow regimes; namely, the smooth inverted annular flow-section, the rough wavy, agitated and dispersed flow regimes.

International Nuclear Information System (INIS)

In this paper, the widely used models of Taitel-Dukler and Weisman et al. are extrapolated to microgravity levels to compare predicted flow pattern boundaries for horizontal and vertical flows. Efforts have been made to analyze how the two-phase flow models available in the literature predict flow regime transitions in microgravity. The models of Taitel-Dukler and Weisman et al. have been found to be more suitable for extrapolation to a wide range of system parameters than the other two-phase flow regime maps available in the literature. The original criteria for all cases are used to predict the transition lines, except for the transition to dispersed flow regime in case of the Weisman model for horizontal flow. The constant 0.97 on the righthand side of this correlation should be two times that value, i.e., 1.94, in order to match this ...

Science.gov (United States)

... 14(a)), a short laminar separation bubble is evident on the ... Natural Laminar Flow and Laminar Flow Control, RW Barnwell and MY ... AGARD CP No. ...

UK PubMed Central (United Kingdom)

Absolute measurements of cerebral blood flow (CBF) are an important endpoint in studies of cerebral pathophysiology. Currently no accepted method exists for in vivo longitudinal...Full Text Available

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... lated Reynolds number for separation is too small. Now ... lol (1959). 6.) F.Schultz-Grunow On stability of Couette flow, AGARD- ...

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Jan 31, 2002 ... Sequential Flow of EDA Functionality for Flow with Separation ...... for Automated Air Traffic Management," AGARD Lecture Series No. ...

International Nuclear Information System (INIS)

... 5. Formation of the annular two-phase flow regime, with a wavy film on the

Science.gov (United States)

... of the cycle shows that the separation area ea. ... with suitable flow solvers based on the Reynolds ... AGARD 75th Fluid Dynamics Panel Meeting and ...

UK PubMed Central (United Kingdom)

Flow cytometry (FCM) is widely used in health research and in treatment for a variety of tasks, such as in the diagnosis and monitoring of leukemia and lymphoma patients, providing the counts of helper-T...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A visual study of film boiling using photographic and high speed motion-picture methods was carried out to determine the flow regime transition criteria in the post-CHF region. An idealized inverted annular flow was obtained by introducing a liquid jet of Freon 113 through a nozzle, precisely centered with respect to the internal diameter of the test section, with an annular gas flow. The respective ranges for liquid and gas exit velocities were 0.05 to 0.5 and 0.03 to 7.9 m/s. Nitrogen and helium were used in the study. For the present configuration, there are four basic flow regimes. Beginning from the nozzle exit, there is a smooth, inverted annular flow section with liquid in the core and gas in the annulus; followed by the rough wavy section with an intact liquid core, the agitated and the dispersed flow regimes. For a given liquid jet velocity, the axial ...

International Nuclear Information System (INIS)

This work presents an experimental and numerical study of pulsated Dean flow, three-dimensional pulsatile flow in a curved pipe. The numerical study is performed by CFD code (Fluent 6) in which a pulsated velocity field is imposed as an inlet condition. The experimental setup involves principally a 'Scotch-yoke' pulsatile generator and a 90o bend. Laser Doppler Velocimetry (LDV) measurements have shown that the Scotch-yoke generator produces pure sinusoidal instantaneous mean velocities with a mean deviation of 3%. Visualizations by laser-induced fluorescence (LIF) and velocity measurements, coupled with the numerical results, have permitted analysis of the evolution of the swirling secondary flow structures that develop along the bend during the pulsation phase. These measurements were made for a range of stationary Reynolds number (300?Rest?1200), frequency parameter (1??=r0(?/?)1/2max,osc/Ust). We observe satisfactory ...

International Nuclear Information System (INIS)

The structure of the P-2, S-1 accelerator mode with one step, S-1, on double period, P-2 for systems, described by the Harper mapping as well as by standard mapping, is analyzed. Detailed analysis of stability criteria is given and comparison with the results of numerical analysis is performed. Three-period compression of the P-2, S-1 island is revealed in the standard mapping. Refs. 7, figs. 7.

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This is an inquiry-based module created specifically for use with the PhET simulation Geometric Optics. It includes a lesson plan for teaching about convex lenses, step-by-step student directions, and a set of Power Point "clicker" questions for use as warm-up questions or informal assessment. This resource is part of a larger collection of interactive Java simulations for students of physics, developed by the Physics Education Technology project at the University of Colorado.

Energy Technology Data Exchange (ETDEWEB)

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

Science.gov (United States)

Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.

International Nuclear Information System (INIS)

A series of real-time, neutron radiography, experiments are ongoing at the Texas A and M Nuclear Science Center Reactor (NSCR). These tests determine the resolving capabilities for radiographic imaging of two phase water and air flow regimes through small diameter flow channels. Though both film and video radiographic imaging is available, the real-time video imaging was selected to capture the dynamic flow patterns with results that continue to improve. (author)

International Nuclear Information System (INIS)

We apply our work on fracture- and matrix-dominated flow to develop a conceptual model of hydrological flow processes in the unsaturated zone at Yucca Mountain. The possibility of fracture-dominated flow is discussed, and various deductions are made on its impact on natural and total system performance, site characterization activities, and site suitability determination.

Czech Academy of Sciences Repository

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The presentation deals with the flows on the primary side of a horizontal steam generator under conditions typical to natural circulation cooling of the reactor. The main goal is to analyse the effect of primary flow patterns on the heat transfer capability of the steam generator. Conclusions pertinent to steam generator modelling with system codes are also drawn. (10 refs., 9 figs., 4 tabs.).

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Transonic flows with heat addition due to condensation are important to many technical applications, e.g. to the last stages of large steam turbines, where nucleation and droplet formation become important. Our current research concentrates on the interaction of vortex shedding with condensation in turbines and on rotor/stator interaction in nucleating flows. Both phenomena lead to a significant change of the condensate mass and the droplet radius distribution in the downstream two-phase flow regime. (orig.)

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Science.gov (United States)

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International Nuclear Information System (INIS)

... bypasses control rod drives cylinders electromagnetic pumps fluid flow fluidic

Science.gov (United States)

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KoreaScience (Korea)

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International Nuclear Information System (INIS)

Two sets of analytical correlations describing transitions between two-phase flow regimes are reviewed and discussed. One, the T-D set, is based on mechanistic models; the other, the Weisman set, on experimental correlations. The T-D set is preferred for horizontal flow, whereas the Weisman set seems preferrable for vertical flow. A computer code (FLOP) based on the T-D theory is described and applied to validate the theory.

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

The purpose of the work described in this dissertation is to increase the understanding of injection-pultrusion process. Three major substudies related to injection-pultrusion have been completed: measurement of the compressibility of fiber reinforcements, measurement of in-plane and transverse resin flow through fiber reinforcements, and development of a resin flow model. This dissertation also presents results of an experimental and analytical investigation of in-plane and transverse resin flow through fiber reinforcements.

KoreaScience (Korea)

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KoreaScience (Korea)

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British Library Electronic Table of Contents (United Kingdom)

In this study, the effects of channel surface wettability, cross-sectional geometry and orientation on the two-phase flow in parallel gas channels of proton exchange membrane fuel cells (PEMFCs) are investigated. Ex situ experiments were conducted in flow channels with three different surface wettability (hydrophilically coated, uncoated, and hydrophobically coated), three cross-sectional geometries (rectangular, sinusoidal and trapezoidal), and two orientations (vertical and horizontal). Flow pattern map, individual channel flow variation due to maldistribution, pressure drop and flow visualization images were used to analyze the two-phase flow characteristics. It is found that hydrophilically coated gas channels are advantageous over uncoated or slightly hydrophobic channels regarding un...

British Library Electronic Table of Contents (United Kingdom)

The wind turbines with a flanged-diffuser shroud-so called ?wind lens turbine??-are developed as one of high performance wind turbines by Ohya et al. In order to investigate the flow characteristics and flow acceleration, the paper presents the flow velocity measurements of a long-type and a compact-type wind turbines with a flanged-diffuser shroud by particle image velocimetry. In the case of the long type wind turbine, the velocity vectors of the inner flow field of the diffuser for turbine blades rotating and no blades rotating are presented at Reynolds number, 0.9?105. Furthermore the flow fields between with and without rotating are compared. Through the PIV measurement results, one can realize that the turbine blades rotating affects as suppress the disturbance and the flow separatio...

British Library Electronic Table of Contents (United Kingdom)

Turbulent shear flows on shallow continental shelves (here shallow means that the interaction with the solid, no-slip bottom is important) are of great importance because tide- and wind-driven flows on the shelf are drivers of the transfer of momentum, heat, and mass (gas) across the air?sea interface. These turbulent flows play an important role because vertical mixing and current are vectors for the transport of sediment and bioactive material on continental shelves. Understanding the dynamics of this class of flows presents complications because of the presence of a free surface and also because the flow can be driven by a pressure gradient (a tidal current), a stress at the free surface (a wind-driven current), or a combination of both. In addition, the flow can be modified by the pres...

International Nuclear Information System (INIS)

The present paper deals with the experimental determination of pressure drop across a four-cusped vertical channel. This geometry represents, ideally, the blockage condition in a typical pressurized water reactor with core degraded by accident. Experiments were performed for both single and two-phase flow. Water was utilized for the single-phase measurements whilst simultaneous flow of air and water simulated the steam-water flow. Observation of the prevailing two-phase flow regime was carried out, so that its mechanism could be fully understood. The averaged void fraction was also measured, by the gamma-ray attenuation technique. A wide range of water and air mass flow rates was covered, so that all flow conditions, possible to exist in a reactor with LOCA, could be investigated. New correlations for pressure drop are proposed. (Author).

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,#theta#) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug ...

Energy Technology Data Exchange (ETDEWEB)

A safety analysis code to design a pressurized water reactor and to obtain the licenses including entire proprietary rights is under development in domestic R and D project. The tasks of KAERI is to develop the constitutive relations including models for defining flow regimes and flow regime related models for inter-phase friction, wall frictions, wall heat transfer, and interphase heat and mass transfer in the two-phase three-field equations. In this paper, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical tubes.

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We have developed EOS7M, a ferrofluid flow and transport module for TOUGH2. EOS7M calculates the magnetic forces on ferrofluid caused by an external magnetic field and allows simulation of flow and advective transport of ferrofluid-water mixtures through porous media. Such flow problems are strongly coupled and well suited to the TOUGH2 framework. Preliminary applications of EOS7M to some simple pressure and flow problems for which experiments were carried out in the lab show good qualitative agreement with the laboratory results.

International Nuclear Information System (INIS)

The development of new electro-optical instrumentation for studying the annular dispersed two-phase flow regime is described. The system measures the thickness of the water film and droplet size and velocity distributions which would be encountered in such a flow regime. The water film thickness is measured by an improved capacitance method with a short time constant using newly developed sensor electrodes. The electrodes are made flush with the inner wall of a cylindrical tube and do not disturb the flow. In the test equipment, steady, laminar flow of water along the inner wall of the tube is controlled by appropriate valves and a porous jacket while droplets are introduced by means of a special spray nozzle.

Energy Technology Data Exchange (ETDEWEB)

In the design of natural gas compressor stations, a check valve is a critical element which is commonly placed on the discharge side of the compressor to prevent reverse flow that can cause serious damage to the compressor itself and other components such as seals and bearings. One of the selection criteria of the check valve for this particular application is the valve flow characteristics in steady flow, and its dynamic characteristics in unsteady flow operation. With regards to steady flow valve characteristics, current models for the determination of the check valve open angle vs. mean flow velocity are based on semi-empirical data obtained from water tests, which were found to deviate from measurements in compressible flows. This paper presents results of steady compressible flow testing of an NPS 4 swing type check ...

British Library Electronic Table of Contents (United Kingdom)

The growth of silver chloride nanoparticles on ancient textile was achieved by sequential dipping steps in alternating bath of potassium chloride and silver nitrate under ultrasound irradiation. The effect of ultrasound irradiation and sequential dipping steps in growth of the AgCl nanoparticles has been studied. These systems depicted a decrease in the particles size accompanying a decrease in the sequential dipping steps. The samples were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy. XRD analyses indicated that the prepared AgCl nanoparticles on fiber were crystalline. The textile samples containing AgCl nanoparticles were tested for their antibacterial efficacy against Escherichia coli and were found to possess significant antibacterial activity.

British Library Electronic Table of Contents (United Kingdom)

Mineral carbonation is based on the reaction of carbon dioxide with metal-oxide bearing minerals, usually containing magnesium or calcium silicate, to form hardly soluble carbonates and other solid byproducts. The concept is based on acceleration of the naturally occurring rock weathering process. In the present work the calcium silicate is present in the mineral, wollastonite. To accelerate the process and make it potentially useful for practical applications, mineral carbonation is conducted here using an indirect two-step route in which the reactive component (Ca^2^+ ions in considered case) is first extracted from the mineral matrix and afterwards carbonated. Two solid byproducts are formed in this process: silica in the extraction step and calcium carbonate in the carbonation step. In...

Energy Technology Data Exchange (ETDEWEB)

Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and ...

Energy Technology Data Exchange (ETDEWEB)

A method is described for controlling fuel injection in a diesel engine having a fuel injection nozzle, comprising the steps of: detecting an idling state of the diesel engine and pressure in a combustion chamber; obtaining a pressure increment rate from the pressure detected by the detecting step; selecting a valve opening pressure of the fuel injection nozzle at a relatively low level when the idling state is detected by the detecting step, thereby setting a two peaks characteristics of a fuel injection rate; and controlling the fuel injection nozzle in response to the pressure increment rate so that the pressure increment rate in the combustion chamber is maintained within a predetermined value by changing a fuel injection quantity of a pilot injection from the fuel injection nozzle.

Energy Technology Data Exchange (ETDEWEB)

The Council for Research in Agriculture, Agricultural Engineering Research Unit (CRA-ING) in Rome, Italy has developed an innovative short-rotation forestry (SRF) harvesting system. The system involves a 2 step operation, notably the tree felling and inter-row windrowing performed by a feller windrower equipment; and subsequent chipping performed by a harvester equipped with a pick-up device. The low moisture content of the windrowed trees at harvesting time affects their physical qualities and mechanical strength throughout the chipping operation. The purpose of this study was to analyze the moisture losses of windrowed trees, in relation to the windrow location, on field storage and weather condition. In addition, the study characterized chips quality changes during on field storage by the 2 different harvesting systems. The innovative 2-step system was compared with the traditional 1-step harvesting system.

British Library Electronic Table of Contents (United Kingdom)

Managing service quality is vital to retain customer satisfaction and augment revenues for any business organization. Often it is difficult to assess service quality due to lack of quantifiable measures and limited data. In this paper, we present a hybrid approach based on SERVQUAL and fuzzy TOPSIS for evaluating service quality of urban transportation systems. The proposed approach consists of three steps. The first step involves development of a SERVQUAL based questionnaire to collect data for measuring transportation service quality. The participants provide linguistic assessments to rate the service quality criteria and the alternatives. In step 2, the linguistic ratings are combined through fuzzy TOPSIS to generate an overall performance score for each alternative. The alternative wit...

Energy Technology Data Exchange (ETDEWEB)

The two-phase flow regime transition in a large diameter (I.D.=200mm) vertical pipe was experimentally investigated using a dual-sensor optical probe. The flow transitions from bubbly to chum without an intermediate slug flow regime as the air flow rate is increased. The transition boundaries developed for bubbly to slug flow in small diameter pipes are compared to the bubbly to chum flow transition of the present experiment. The bubbly to chum transition occurs at a void fraction of about 0.15 compared to 0.25 for bubbly to slug transition in small diameter pipes. The radial distribution of bubble diameter, bubble frequency, bubble velocity and local void fraction were obtained using a dual-sensor optical probe at different flow conditions. The Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of the bubble ...

Energy Technology Data Exchange (ETDEWEB)

Liquid metal cooling for the first wall and blanket of a magnetic confinement fusion reactor has various advantages. However, it has the disadvantages of large magnetohydrodynamic pressure drops and heat transfer deterioration under a strong magnetic field. Thus, the present authors have proposed cooling with a helium-lithium annular mist flow as well as the cooling with a liquid metal boiling flow, and as fundamental studies, investigated the effect of a magnetic field on the flow characteristics and heat transfer of liquid metal two-phase systems since the 1970s. In the present paper we summarize the important findings obtained from our experimental studies for (i) an air-mercury stratified flow in a horizontal rectangular channel, (ii) a helium-lithium annular mist flow in a horizontal rectangular channel, (iii) the mercury pool boiling on a horizontal surface, and (iv) ...

CERN Document Server

It is shown that the physical interpretation of Elie Cartan three-dimensional space torsion as couple asymmetric stress, has the effect of damping, previously Riemannian unstable Couette planar shear flow, leading to stability of the flow in the Lagrangean sense. Actually, since the flow speed is inversely proportional to torsion, it has the effect of causing a damping in the planar flow atenuating the instability effect. In this sense we may say that Cartan torsion induces shear viscous asymmetric stresses in the fluid, which are able to damp the instability of the flow. The stability of the flow is computed from the sectional curvature in non-Riemannian three-dimensional manifold. Marginal stability is asssumed by making the sectional non-Riemannian curvature zero, which allows us to determine the speeds of flows able to induce this ...

Energy Technology Data Exchange (ETDEWEB)

Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event ...

International Nuclear Information System (INIS)

The core of Prismatic Modular Reactor (PMR) consists of assemblies of hexagonal graphite fuel and reflector elements. The core bypass flow of Very High Temperature Reactor (VHTR) is defined as the core flow that does not pass through the coolant channels but passes through the bypass gap between fuel elements. The increase in bypass flow makes the decrease in effective coolant flow. Since the core bypass flow has a negative impact on safety and efficiency of VHTR, core bypass phenomena have to be investigated to improve the core thermal margin of VHTR. For this purpose, the international project, I-NERI project, has been carried out since 2008. I-NERI project is collaborative project that KAERI and SNU of Korea side and INL, ANL and TAMU of U.S side are involved. In order to evaluate the core bypass flow, the multicolumn and multi-layer experimental facility is ...

Energy Technology Data Exchange (ETDEWEB)

The marine reactor MRX, an integral typed PWR with 100 MWt adopts one-through steam generators with coiling tubes. The cold feed water enters the steam generator and the super heated steam flows out. To avoid occurrence of flow instability in the steam generator due to a density wave oscillation, it is necessary to increase of flow resistance at the feed water inlet. The magnitude of flow resistance to stabilize the flow is determined by a simple linear analysis using a D-division method, of which accuracy is clarified by comparison with SRI's experiment. The external force due to heaving, one of ship motions will affect the flow behavior. Analysis by a modified RELAP5 capable of simulating the ship motions reveals that the effect of heaving becomes especially greater when the state of flow approaches both the conditions of density ...

Energy Technology Data Exchange (ETDEWEB)

Although incompressible fluid flows can be regarded as a particular case of a general problem, numerical methods and the mathematical formulation aimed to solve compressible and incompressible flows have their own peculiarities, in such a way, that it is generally not possible to attain both regimes with a single approach. In this work, we start from a typically compressible formulation, slightly modified to make use of pressure variables and, through augmenting the stabilising parameters, we end up with a simplified model which is able to deal with a wide range of flow regimes, from supersonic to low speed gas flows. The resulting methodology is flexible enough to allow for the simulation of liquid flows as well. Examples using conservative and pressure variables are shown and the results are compared to those published in the literature, in order to validate the method. (author)

Science.gov (United States)

A theory for the mass transfer process was developed. It was assumed that the largest convective motions in the flow control the rate of mass transfer. Measurements of mass transfer coefficients for the absorption of oxygen by water films were made for concurrent flows in a horizontal rectangular channel, and for concurrent and free-falling downflow in a one-inch pipe. The measured values of the Sherwood number for concurrent flows were up to three times as great as would be predicted from this relation. This increase in Sherwood number was correlated with a dimensionless group similar to a Martinelli parameter which is characteristic of two phase flows. An explanation for this effect is given in terms of the way that the scales of the convective motions are related to bulk flow parameters.

Energy Technology Data Exchange (ETDEWEB)

Thermal hydraulics of a liquid metal is important to design the blanket of a magnetic confined fusion reactor. Since a liquid metal has high thermal and electrical conductivity, the flow characteristics are often different from those of an ordinary liquid like water especially in thermal convection and under a magnetic field. It is difficult to simulate such flows in a liquid metal cooled blanket by water. Flow visualization is a popular method to study thermal hydraulics. Since most of metals are visible by neutron rays, neutron radiography is available to the flow visualization of a liquid metal. The purpose of this study is to develop a visualization technique of the flow in a liquid metal by real-time neutron radiography using the tracer and the dye injection methods. A real-time thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute was used for ...

International Nuclear Information System (INIS)

Purpose: To stably control the reactor water level so as not to cause excess water feeding in a BWR type reactor. Constitution: A flow control valve is disposed to the exit of a feedwater pump for a nuclear reactor and the valve is controlled by a flow regulator to maintain the water level constant in the reactor. A signal from a water level controller is inputted to the flow regulator to thereby control the flow rate control valve. In this case, the flow regulator remains in a saturated state just after the starting of the feedwater pump, in which the pump flowrate is at 100% to result in an excess water feeding condition. In view of the above, a feedback circuit is provided to the flow regulator so that the saturated state is eliminated and the water feeding can be controlled directly from the water level controller. (Kamimura, M.).

Energy Technology Data Exchange (ETDEWEB)

As part of the EPRI Motor-Operated Valve (MOV) Performance Prediction Methodology, a System Flow Model (SFM) has been developed to determine the differential pressure (DP) across MOVs as they are stroked in typical power plant systems. Input to the SFM includes valve flow characteristics (such as flow coefficient) and system characteristics (such as pump head/flow curve). The primary output is differential pressure across the valve at each stroke position. The SFM was validated by comparison with test data from the EPRI Flow Loop Test Program. In this study, we calculated DP using SFM and performed DP test for four MOVs. Compared between calculated DP and test DP of four MOV, respectively good agreements are found. (author). 6 refs., 9 figs., 1 tab.

UK PubMed Central (United Kingdom)

AbstractThe optimal definition of the size, shape and location of gross tumour volume is one of the most important steps in the planning of radiation therapy, and necessitates a proper...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10{sup -5} g h{sup -1} into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10{sup 8} is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10{sup 5} for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination ...

UK PubMed Central (United Kingdom)

Many simulation studies in biomedicine are based on a similar sequence of processing steps, starting from images and running through geometric model generation, assignment of tissue properties, numerical...Full Text Available

UK PubMed Central (United Kingdom)

A final step in the influenza virus replication cycle is the assembly of the viral structural proteins and the packaging of the eight segments of viral RNA (vRNA) into a fully infectious virion. The...Full Text Available

UK PubMed Central (United Kingdom)

The rate-limiting step in the transit of dietary fat across the intestinal absorptive cell is its exit from the endoplasmic reticulum (ER) in a specialized ER-to-Golgi transport vesicle, the prechylomicron...Full Text Available

UK PubMed Central (United Kingdom)

Contemporary high dimensional biological assays, such as mRNA expression microarrays, regularly involve multiple data processing steps, such as experimental processing, computational processing, sample...Full Text Available

UK PubMed Central (United Kingdom)

Phospho-beta-galactosidase (P-beta-gal), the enzyme which catalyzes the first step in the metabolism of intracellular lactose phosphate, occurred at high specific activity in the cytoplasm in 12 of...Full Text Available

UK PubMed Central (United Kingdom)

Cervical cancer is known to metastasize primarily by the lymphatic system. Dissemination through lymphatic vessels represents an early step in regional tumor progression, and the presence of lymphatic...Full Text Available

Science.gov (United States)

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

UK PubMed Central (United Kingdom)

Chemoprevention, especially through the use of naturally occurring phytochemicals capable of impeding the process of carcinogenesis at one or more steps, is an ideal approach for cancer management....Full Text Available

Science.gov (United States)

The discussion of energy usage falls naturally into three parts. The first is a review of what the problem is, the second is a description of steps that can be taken to conserve energy at existing facilities, and the third is a review of the implications of energy consumption on future facilities.

UK PubMed Central (United Kingdom)

This paper summarizes the findings for the African Region of the WPA Task Force on Steps, Obstacles and Mistakes to Avoid in the Implementation of Community Mental Health Care. We present an overview...Full Text Available

UK PubMed Central (United Kingdom)

Given the high prevalence of overweight and low levels of physical activity among children, a better understanding of physical activity behaviour is an important step in intervention planning. This...Full Text Available

UK PubMed Central (United Kingdom)

Although integration generally is considered a critical step in the retrovirus life cycle, it has been reported that visna virus, which causes degenerative neurologic disease in sheep, can productively...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The technical committees of the International Electrotechnical Committee (IEC) play an important part in preparing international standards. In this report the chairman of the Technical Comittee 14 (Power Transformers) describes the present state and the progressive work.

Energy Technology Data Exchange (ETDEWEB)

The atomic structure of [001] tilt grain boundaries of {Sigma}5 (210), {Sigma}5 (310), {Sigma}13 (320) and {Sigma}17 (410) in TiO{sub 2}(rutile) were studied using high resolution electron microscopy and computer simulation. Regularly separated small steps (1/2 [120] high) and big steps (3/2 [120] high) which contain secondary dislocations were found in the (210) boundary as a result of deviation from the exact {Sigma}5 misorientation and (210) symmetric plane. Similar steps were also found in (310) and (320) boundaries. Flat segments between the steps were found to have very accurate misorientation of the {sigma}`s and a nearly symmetric boundary plane. Their rigid body translation, volume expansion and relaxed structures were determined by comparing HRTEM images with computer calculated structures and simulated images. An irregular core structure was found in the (410) boundary when its misorientation ...

Energy Technology Data Exchange (ETDEWEB)

The various steps of gas treatment in the Sasol II coal liquefaction plant are discussed: CO/sub 2/ removal, separation of the hydrocarbon fractions and the recirculated hydrogen by low-temperature decomposition, production of pure hydrogen by alternating pressure absorption.

UK PubMed Central (United Kingdom)

Mice lacking acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the terminal step in triacylglycerol synthesis, have enhanced insulin sensitivity and are protected from...Full Text Available

UK PubMed Central (United Kingdom)

The hepatic uptake rate for certain albumin-bound drugs and metabolites correlates poorly with their equilibrium unbound concentration in the plasma, suggesting that binding equilibrium may not always...Full Text Available

UK PubMed Central (United Kingdom)

In Pseudomonas paucimobilis UT26, gamma-hexachlorocyclohexane (gamma-HCH) is converted by two steps of dehydrochlorination to a chemically unstable intermediate, 1,3,4,6-tetrachloro-1,4-cyclohexadiene...Full Text Available

UK PubMed Central (United Kingdom)

Regulation of glucose isomerase synthesis was studied in Thermoanaerobacter strain B6A, which fermented a wide variety of carbohydrates including glucose, xylose, lactose, starch, and...Full Text Available

International Nuclear Information System (INIS)

Activities are reported in programs to locate, test, and select materials for borehole plugs near nuclear waste repositories. Background information concerning borehole plugging is presented and work to date is summarized. Borehole sealants considered are listed and recommended steps to plug boreholes are given. Planned research is summarized.

UK PubMed Central (United Kingdom)

Detection and quantification of prion infectivity is a crucial step for various fundamental and applied aspects of prion research. Identification of cell lines highly sensitive to prion infection led...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Inverted annular flow can be visualized as a liquid jet-like core surrounded by a vapor annulus. While many analytical and experimental studies of heat transfer in this regime have been performed, there is very little understanding of the basic hydrodynamics of the post-CHF flow field. However, a recent experimental study was done that was able to successfully investigate the effects of various steady-state inlet flow parameters on the post-CHF hydrodynamics of the film boiling of a single phase liquid jet. This study was carried out by means of a visual photographic analysis of an idealized single phase core inverted annular flow initial geometry (single phase liquid jet core surrounded by a coaxial annulus of gas). In order to extend this study, a subsequent flow visualization of an idealized two-phase core inverted annular flow geometry (two-phase central jet ...

International Nuclear Information System (INIS)

Depending on their unique physical properties, proton and heavy ions have taken an irreplaceable role in modern means of tumor treatment. One-step process and two-step process physical models were employed to explain the mechanism of ion energy loss. The transport process of proton and "1"2C in water was simulated by Geant4 toolkit to study the physical properties of ion beam. The calculation results were discussed, which showed the advantages and disadvantages of proton and "1"2C in the medical application. (authors)

International Nuclear Information System (INIS)

This report issued by the Energy Economics Group and the Laboratory for Energy Systems Analysis at the Paul Scherrer Institute (PSI) analyses current and future trends in the area of energy and mobility on a global, European level as well as with respect to the German-speaking countries Austria, Germany and Switzerland. In a first step, developments with regard to how mobility is achieved and the energy consumption involved are examined and the impact of business-as-usual trends on global carbon dioxide (CO2) emissions and future fuel consumption is discussed. In a second step, the paper outlines potential alternative futures in terms of energy and mobility. Finally, the paper derives and presents recommendations for policy-makers.

Energy Technology Data Exchange (ETDEWEB)

The energy spectra of few-nucleon transfer reactions obtained by bombarding a /sup 197/Au nucleus with the 341 MeV /sup 20/Ne beam of the Berkeley cyclotron have been analysed successfully in terms of direct surface transfer reactions populating the continuum states. At the grazing angle we are dealing with one-step processes; at forward angle two-step processes have to be taken into account.

International Nuclear Information System (INIS)

This handbook breaks down the complex field of nuclear reactor calculations into major steps. Each step presents a detailed analysis of the problems to be solved, the parameters involved, and the elaborate computer programs developed to perform the calculations. This book bridges the gap between nuclear reactor theory and the implementation of that theory, including the problems to be encountered and the level of confidence that should be given to the methods described. Volume II: Monte Carlo Calculations for Nuclear Reactors. In-Core Management of Four Reactor Types. In-Core Management in CANDU-PHW Reactors. Reactor Dynamics. The Theory of Neutron Leakage in Reactor Lattices. Index.

CERN Document Server

A discrete time control algorithm using the damped least squares is introduced for acceleration and energy exchange controls in nonlinear vibrating systems. It is shown that the damping constant of least squares and sampling time step of the controller must be inversely related to insure that vanishing the time step has little effect on the results. The algorithm is illustrated on two linearly coupled Duffing oscillators near the 1:1 internal resonance. In particular, it is shown that varying the dissipation ratio of one of the two oscillators can significantly suppress the nonlinear beat phenomenon.

Energy Technology Data Exchange (ETDEWEB)

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 PSI/Nagra and QuantiSci to provide a new ...