CERN Document Server

After two decades of direct dynamical simulation of large-scale structure in the universe, it is safe to say the subject is now mature. Still, there are parts of the problem that are less well developed than others. In general, the collisionless dynamics of the dark matter component is better understood than the collisional gas dynamics of the baryonic component. In situations where the gas dynamics is relatively simple, such as the Lyman-$\\alpha$ forest and the intracluster medium in X-ray clusters, our ability to reproduce observational data has evolved rapidly, and the interpretive and predictive power of such experiments should now be taken seriously. A comparison of twelve gas dynamic codes to the problem of forming a single X-ray cluster shows that numerical inaccuracies ...

Energy Technology Data Exchange (ETDEWEB)

Many problems in physics necessitate the solution of equations which develop sharp gradients, such as shocks. These include atmospheric shocks near the earth's surface, plasma physics phenomena, both in the laboratory and in space, combustion, petroleum reservoir modelling, and light propagation in glass fibers. To deal with this situation, methods are needed which place a high density of nodes in the neighborhoods of the steep gradients. One of the most promising of these methods is the moving finite element method which was first invented by Miller. This approach, in which the nodes are moved so as to minimize the residual error, has been used successfully by Gelinas, Doss, and co-workers to study several different one-dimensional problems and shows great promise as well in dealing with two dimensions. A paper describing the one-dimensional results has already been published, and a paper describing the two-dimensional results is in ...

International Nuclear Information System (INIS)

This paper deals with construction types of high temperature heat exchangers, their circulation loops and temperature differences. Most attention is given to gas dynamics, convective heat transfer, convection and radiant heat transfer interaction in high temperature heat exchangers. The ways of heat transfer augmentation and efficient heat exchanger construction are discussed.

International Nuclear Information System (INIS)

The study of the dynamics of lubricants and mechanical components encased in metal enclosures is important to many industries. Of particular importance is the flow characteristics of oils or similar lubricants within the metal enclosure during operation of the device. The purpose of this summary is to report on the design and successful application of a real-time neutron radiography system to study the lubrication and design of the piston and seal of a gas spring. In addition, the application of this technique to a wider range of similar problems using the pulse capability of the TRIGA reactor is described.

Energy Technology Data Exchange (ETDEWEB)

This report describes in detail the First Generation Duct Injection Model developed for the analysis of the fundamental processes of flue gas desulfurization by sorbent injection. The model is a two- and three-dimensional, multiphase reacting flow analyzer using computational fluid dynamics methods. The gaseous phase is solved in an Eulerian frame while the droplets or particles are tracked in a Lagrangian frame. The model has an associated preprocessor which allow easy problem set up by the use without in-depth knowledge of computational fluid dynamics. The aerodynamics of the First Generation Duct Injection Model have been successfully validated with a number of test cases for which experimental data are available. Data from the Meredosia pilot plant humidification tests have been used to validate the gas and droplet dynamics of the model with good agreement. ...

International Nuclear Information System (INIS)

... computer calculations fftf reactor nonlinear problems reactor accidents reactor

Energy Technology Data Exchange (ETDEWEB)

In coke-oven operations flue-gas valves are used to switch the regenerator function from rich gas firing to lean gas firing. Compared with the simple geometry of the other parts of the flow path, which comprise flues and regenerators, the narrow and winding passages of the flue-gas valves give rise to relatively high losses in pressure. Without the construction of high (and therefore expensive) chimneys, this means that operating problems may well arise due the inadequate suction capacity. The project focused on the theoretical and experimental analysis of a coke-oven flue-gas valve. The primary aim was to reduce the pressure drop through the valve without modifying its external geomerty. The internal flow characteristics created by different valve geometries under a variety of operating conditions were simulated using the commercial CFD code Fluent/UNS, which ...

Science.gov (United States)

The fuel cell control problem was studied. Attempts were made to control the output current of the fuel cell by starving it of hydrogen and oxygen. The motivation of this work was to increase efficiency by minimizing waste of fuel. The following findings were obtained: H2 starvation works better than O2 starvation; An optimal H2 to O2 ratio exists for combined H2&O2 starvation; The control scheme for H2&O2 starvation works well for 3 different disturbance tests and at 25 degrees C, 60 degrees C, and 80 degrees C; Fuel cell under reactant starvation is stable for at least 72 hrs.

CERN Document Server

We have developed a liquid jet injector system that can be used for hydrated sample delivery at X-ray Free Electron Laser (XFEL) sources and 3rd generation synchrotron sources. The injector is based on the Gas Dynamic Virtual Nozzle (GDVN), which generates a liquid jet with diameter ranging from 300 nm to 20 {\\mu}m without the clogging problems associated with conventional Rayleigh jets. An improved nozzle design is presented here. A differential pumping system protects the vacuum chamber and an in-vacuum microscope allows observation of the liquid jet for diagnostics while it is being exposed to the X-ray beam. A fiber optically coupled pump laser illuminating the jet is incorporated for pump-probe experiments. First results with this injector system have been obtained at the LCLS.

UK PubMed Central (United Kingdom)

Specific criteria have been developed based on computerized dynamic posturography (CDP) to assist clinicians in identifying patients with psychogenic balance problems (Cyr and Cevette, Full Text Available

Science.gov (United States)

... defense's weapons are Space-based kinetic-kill vehicles ... I ti I obtained by dividing the weapons as ... of the optimal weapon-arge assigntments and ...

CERN Document Server

The origin of life and the origin of the universe represent two of the most important problems of science. Both are resolved by hydro-gravitational dynamics (HGD) cosmology (Gibson 1996, Schild 1996, Gibson 2009ab), which predicts frozen primordial hydrogen-helium gas planets in clumps as the dark matter of galaxies. Merging Earth-mass planets formed stars, moons and comets to incubate and cosmically seed the first life. Cometary panspermia (Hoyle and Wickramasinghe 1981, 1982; Wickramasinghe et al. 2009) occurs naturally by HGD mechanisms. Comets and moons are fragments from mergers of stardust covered frozen gas planets in their step-wise growth to star mass. Supernovae from stellar over-accretion of planets produce stardust (C, N, O, P etc.) chemical fertilizer. Planets collect this infected radioactive dust gravitationally, to provide liquid water domains in contact with life nutrients seeded with ...

Science.gov (United States)

the revealed stage of T Tauri star evolution, is only a mere shadow of its former self. Once primary accretion starts, one has the (poorly quantified) ...

Energy Technology Data Exchange (ETDEWEB)

The technology status of the dynamics and controls discipline as it applies to energy storage wheel systems was evaluated. No problems were identified for which an adequate solution could not be proposed. Design issues that influence control were addressed. The dynamics and control aspects associated with the energy storage system concept and its various constituent parts, and the control tasks attendant to large, manned spacecraft are discussed.

International Nuclear Information System (INIS)

1 - Description of program or function: T-HEMP3D (Transportable HEMP3D) is a derivative of the STEALTH three-dimensional thermodynamics code developed by Science Applications, Inc. Changes were made primarily in three areas: material specification, coordinate generation, and the addition of sliding surface boundary conditions. STEALTH itself is based entirely on the HEMP3D code written at LLNL. HEMP3D solves problems in solid mechanics involving dynamic plasticity and time-dependent material behavior and problems in gas dynamics. 2 - Method of solution: The equations of motion, conservation equations, and constitutive relations for stresses, strains, hydrostatic pressure, the von Mises yield condition, and artificial viscosity are solved by finite difference methods following the format of the HEMP code (NESC Abstract 775). The physical object is divided into zones defined by 8 grid ...

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The problems in computer vision range from edge detection and segmentation at the lowest level to the problem of cognition at the highest level. This correspondence describes the organization and operation of a semantic network array processor (SNAP) as applicable to high level computer vision problems. The architecture consists of an array of identical cells each containing a content addressable memory, microprogram control, and a communication unit. The applications discussed in this paper are the two general techniques, discrete relaxation and dynamic programming. While the discrete relaxation is discussed with reference to scene labeling and edge interpretation, the dynamic programming is tuned for stereo.

International Nuclear Information System (INIS)

Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

British Library Electronic Table of Contents (United Kingdom)

This article presents a decentralized control scheme for the complex problem of simultaneous position and internal force control in cooperative multiple manipulator systems. The proposed controller is composed of a sliding mode control term and a force robustifying term to simultaneously control the payloads position/orientation as well as the internal forces induced in the system. This is accomplished independently of the manipulators dynamics. Unlike most controllers that do not require prior knowledge of the manipulators dynamics, the suggested controller does not use fuzzy logic inferencing and is computationally inexpensive. Using a Lyapunov stability approach, the controller is proven to be robust in the face of varying systems dynamics. The payloads position/orientation and the inte...

Science.gov (United States)

The report gives a comprehensive summary of the experience gained and the problems encountered during the Cat-Ox demonstration program. The report outlines the process design and construction, as well as operating experience and problems. Test results and conclusions derived from...

Science.gov (United States)

This project addresses the problem of flue gas desulfurization (FGD) sludge disposal to land. Specifically, the chemical species of FGD sludge constituents are thermodynamically modeled using the equilibrium constant approach, in an attempt to predict the constituent concentratio...

International Nuclear Information System (INIS)

The purpose of this investigation is to show that resource to anisotropic compression along a magnetic field is not a necessary condition for star formation within large collapsing interstellar gas clouds. Although such a scenario would certainly eliminate the magnetic field and angular momentum problems associated with isotropically collapsing clouds, it is believed there is sufficient observational theoretical evidence to warrant the present study of magnetically braked, isotropically collapsing gas clouds. It is not attempted to disprove the hypothesis of anisotropic compression, but to offer instead, a reasonable alternative. Angular momentum transfer from magnetically braked, cool interstellar gas clouds of 10"2, 10"3 and 10"4 times the mass of the sun is examined. Magnetic torques acting on a contracting, rotating cloud, permeated by a frozen-in magnetic field coupling the cloud to the galactic ...

Science.gov (United States)

The H-Coal ebullated bed reactor contains at least four discrete components: gas, liquid, catalyst, and unconverted coal and ash. Because of the complexity created by these four components, it is desirable to understand the fluid dynamics of the system. The objective of this program is to establish the dependence of the ebullated bed fluid dynamics on process parameters. This will permit improved control of the ebullated bed reactor. Progress has been made in the study undertaken for defining the hydrodynamic properties of gas/liquid/solid systems as related to the H-Coal process. The literature search was completed, and a report will be issued shortly. Design and construction of the fluid dynamics unit proceeded as planned. Unit completion is scheduled for May 1, 1978.

Science.gov (United States)

During the entire performance period, from 12 May 2003 through 31 December 2006, we have conducted theoretical and computational research on quantum control problems central to quantum computation. In particular we completed a thorough and rigorous analys...

International Nuclear Information System (INIS)

Natural gas is essential to the world economy. Gas now accounts for almost a quarter of OECD primary energy requirements and is expected to become the second most important fuel in the world in the next decade. Industrial and residential consumers increasingly rely on natural gas to keep their houses warm, their lights on and their factories running. Meanwhile the gas industry itself has entered a new phase. Where gas used to be restricted to regional markets, it is now increasingly traded on a global scale. While gas production and transport requires long-term investment, now it is optimised on a short-term basis. Demand continues to grow, but local gas production has become much more expensive. How should we react? How will demand be satisfied? What changes are required to promote flexibility and trade? What are the implications for ...

Science.gov (United States)

The dynamic response characteristics of the VAWT rotor are important factors governing the safety and fatigue life of VAWT systems. The principal problems are the determination of critical rotor speeds (resonances) and the assessment of forced vibration response amplitudes. The solution to these problems is complicated by centrifugal and coriolis effects which can have substantial influence on rotor resonant frequencies and mode shapes. This paper will describe and discuss the primary tools now in use at Sandia National Laboratories for rotor analysis. These tools include a lumped springmass model (VAWTDYN) and also finite-element based approaches. The discussion will center on the accuracy and completeness of current capabilities and plans for future research.

Energy Technology Data Exchange (ETDEWEB)

Rapid technology improvements, resulting in high efficiency, emissions reduction and low generation cost, are making gas turbines the generation technology of choice despite some recent reliability problems. The basic reason for the dominance is high efficiency. The rapid pace of gas-turbine technology improvement in the 1990s drove combined-cycle thermal efficiency to nearly 60 percent with natural gas as the fuel. It will probably go even higher after the year 2000. In addition, the gas-fired combined cycle is a bargain. With natural gas prices where they are right now, it is the least-cost generation operation for power producers with access to gas. Many will replace older, high-cost power plants with new gas-fired combined cycle power plants.

Energy Technology Data Exchange (ETDEWEB)

This article outlines the use of gasifiers during World War II and how, with soaring fuel prices, producer gas may provide an alternate energy path for agribusiness and farms today. In the last few years, the University of California has become a focus of producer gas research in the US. Biomass fuels used include crushed walnut shells, fruit pits, cereal straw and corn cobs. Particle size, moisture content and slagging create problems and the right kind of gas producer must be used to obtain reliable conversion to producer gas.

CERN Document Server

We investigate the chemical and observational implications of repetitive transient dense core formation in molecular clouds. We allow a transient density fluctuation to form and disperse over a period of 1 Myr, tracing its chemical evolution. We then allow the same gas immediately to undergo further such formation and dispersion cycles. The chemistry of the dense gas in subsequent cycles is similar to that of the first, and a limit cycle is reached quickly (2 - 3 cycles). Enhancement of hydrocarbon abundances during a specific period of evolution is the strongest indicator of previous dynamical history. The molecular content of the diffuse background gas in the molecular cloud is expected to be strongly enhanced by the core formation and dispersion process. Such enhancement may remain for as long as 0.5 Myr. The frequency of repetitive core formation should strongly determine the level of background ...

Science.gov (United States)

A series of studies conducted to identify the factors that block and unblock problem solving is described. Through the construction of an isomorph of the classic "water jar" problems developed by A. S. Luchins (1942) as a dynamic graphic micro-world, several factors involved in producing blocked states were identified. Subjects included 10 individuals and 10 pairs of subjects. By comparing the behavior of individuals tackling the "missionaries and cannibals" problem to that of pairs of subjects solving this problem, a study identified means by which problem solvers operating in a social context are able to overcome blocks that discourage individuals. These studies point to the importance of "reflection" (evaluation of problem-solving results) for flexible problem solving. This research suggests that teaching students to ...

CERN Document Server

We discuss the Sundman-Weierstrass theorem of total collapse in its historical context. This remarkable and relatively simple result, a type of stability criterion, is at the crossroads of some interesting developments in the gravitation Newtonian N-body problem. We use it as motivation to explore the connections to such important concepts as integrability, singularities and tyipicality in order to gain some insight on the transition from a predominantly quantitative to a novel qualitative approach to dynamical problems that took place at the end of the 19th century.

Energy Technology Data Exchange (ETDEWEB)

Sufficient passing sight distance is an important control for two-lane rural highway design to minimize the possibility of a head-on collision between passing and opposing vehicles. Traditionally, passing zones are marked by checking passing sight distance that is potentially restricted by static sight obstructions. Such obstructions include crest curves, overpasses, and lateral objects along highways. This paper proposes a new concept of dynamic sight-distance assessment, which involves restricted passing sight distances due to the impeding vehicles that are traveling in the same direction. Using a finite-element model, the dynamic passing sight-distance problem was evaluated, and the writers analyzed the relationships between the available passing sight distance and other factors such as the horizontal curve radius, impeding vehicle dimensions, and a driver s following distance. It was found that the impeding vehicles may ...

Energy Technology Data Exchange (ETDEWEB)

Slowly, scientists come to realize that there are huge quantities of natural methan hydrates and their interest is awakened. Important questions in this connection are their possible use as future energy sources, the consequences of using methan hydrates on the climate, their integration into the carbon cycle, the cementation of the continental slopes by gas hydrates and their stability and their role in some geological-biological-geochemical processes, especially in the marine area. Towards the end of the 20th century, the basic problems and applied problem scenarios, e.g. the foundation of production platforms dor petroleum and natural gas in gas-hydrate-containing sediments, was the reason for Japan, Canada, USA, China, Germany and India to install national research programmes of various sorts in order to deal with the problems of gas ...

Energy Technology Data Exchange (ETDEWEB)

Laboratory research data is used as the basis for recommendations to be used in selecting a modification regime employing the treatment of clinoptilolite with NS1 to remove mercaptans from natural gas. The dynamic activity of the modified clinoptilolite is seven times greater than the activity of nontreated material.

CERN Document Server

We present a HST/STIS spectroscopic and optical/radio imaging study of the Seyfert NGC 2110 aiming to measure the dynamics and understand the nature of the nuclear outflow in the galaxy. Previous HST studies have revealed the presence of a linear structure in the Narrow-Line Region (NLR) aligned with the radio jet. We show that this structure is strongly accelerated, probably by the jet, but is unlikely to be entrained in the jet flow. The ionisation properties of this structure are consistent with photoionisation of dusty, dense gas by the active nucleus. We present a plausible geometrical model for the NLR, bringing together various components of the nuclear environment of the galaxy. We highlight the importance of the circum-nuclear disc in determining the appearance of the emission line gas and the morphology of the jet. From the dynamics of the emission line gas, we place ...

Energy Technology Data Exchange (ETDEWEB)

An analysis is made of the manner in which the process of primordial black-hole formation and the subsequent accretion of gas depend on the equation of state. On the assumption that the process is spherically symmetric, the problem is solved numerically.

International Nuclear Information System (INIS)

This paper presents a practical case study on the dynamic stability of the Saudi Electricity Company (SEC) power system and its effect on increasing power transfer limit of the interconnection between Eastern Operating Area (SEC-EOA). The problem of optimal tuning of the power system stabilizer parameters was converted into optimization problem wth eigenvalue-based objective functions, which was then solved by genetic algorithms. In this regard, two eigenvalue-based objective functions were considered and the problem is solved using real-coded genetic algorithm (RCGA). The effectiveness of the suggested technique to enhance the power system dynamic stability and to extend the power transfer capability limit of the SEC-EOA and the SEC-EOA power system was verified through a comprehensive eigenvalue analysis and time-domain nonlinear simulation. The results also indicated that the ...

International Nuclear Information System (INIS)

Many countries are liberalizing their energy markets. Participants in these markets are exposed to market risk due to the characteristics of electricity price dynamics. Electricity prices are known to be mean-reverting very volatile and subject to frequent spikes. Models that describe the dynamics of electricity prices should incorporate these characteristics. In order to capture the price spikes, many researchers have introduced stochastic jump processes, but we argue and show that this specification might lead to potential problems with specifying the true amount of mean-reversion within the process. In this paper, we propose a regime-switching model that models price spikes separated from normal mean-reverting prices.

Energy Technology Data Exchange (ETDEWEB)

This article proposes a model for estimating the effect of the overall thermal resistance of the absorber and the coolant on a solar thermal energy system utilizing advanced heat transfer mediums. Two equations can be used to model a dynamic system: one for the maximum conversion efficiency and one to specify the constraint that, in quasi-steady state, the net energy collected must be transferred to the coolant. These two equations define a constrained optimization problem in two variables, the fluid and the absorber temperatures. The results present interesting implications for liquid metal, direct absorption, and solar evaporating systems.

Energy Technology Data Exchange (ETDEWEB)

This contribution is an informal essay based on a talk delivered at the Institute for Mathematics and its Applications (IMA) in Minneapolis, under the summer program in molecular biology, July 18-22, 1994. I exclude many technical details, which can be found elsewhere, and instead focus on the basic ideas of molecular dynamics simulations, with the goal of conveying to students and non-specialists the key concepts of the theory and practice of large-scale simulations. Following a description of the basic idea in molecular dynamics, I discuss some of the practical details involved in simulations of large biological molecules, the numerical timestep problem, and approaches to this problem based on implicit-integration techniques. I end with a perspective of open challenges in the field and directions for future research. 79 refs., 6 figs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

We provide an efficient computational approach to solve the mixed integer programming (MIP) model developed by Tarim and Kingsman [8] for solving a stochastic lot-sizing problem with service level constraints under the static-dynamic uncertainty strategy. The effectiveness of the proposed method hinges on three novelties: (i) the proposed relaxation is computationally efficient and provides an optimal solution most of the time, (ii) if the relaxation produces an infeasible solution, then this solution yields a tight lower bound for the optimal cost, and (iii) it can be modified easily to obtain a feasible solution, which yields an upper bound. In case of infeasibility, the relaxation approach is implemented at each node of the search tree in a branch-and-bound procedure to efficiently sear...

Energy Technology Data Exchange (ETDEWEB)

This report is a scoping study to examine research opportunities to improve the accuracy of the system dynamic load and generator models, data and performance assessment tools used by CAISO operations engineers and planning engineers, as well as those used by their counterparts at the California utilities, to establish safe operating margins. Model-based simulations are commonly used to assess the impact of credible contingencies in order to determine system operating limits (path ratings, etc.) to ensure compliance with NERC and WECC reliability requirements. Improved models and a better understanding of the impact of uncertainties in these models will increase the reliability of grid operations by allowing operators to more accurately study system voltage problems and the dynamic stability response of the system to disturbances.

CERN Document Server

We introduce an ad-hoc electrodynamics with advanced and retarded Lienard-Wiechert interactions plus the dissipative Lorentz-Dirac self-interaction force. We study the covariant dynamical system of the electromagnetic two-body problem, i.e., the hydrogen atom. We perform the linear stability analysis of circular orbits for oscillations perpendicular to the orbital plane. In particular we study the normal modes of the linearized dynamics that have an arbitrarily large imaginary eigenvalue. These large eigenvalues are fast frequencies that introduce a fast (stiff) timescale into the dynamics. As an application, we study the phenomenon of resonant dissipation, i.e., a motion where both particles recoil together in a drifting circular orbit (a bound state), while the atom dissipates center-of-mass energy only. This balancing of the stiff dynamics is established by the existence of a ...

Energy Technology Data Exchange (ETDEWEB)

The climate modeling community has focused recently on improving our understanding of certain processes, such as cloud feedbacks and ocean circulation, that are deemed critical to climate-change prediction. Although attention to such processes is warranted, emphasis on these areas has diminished a general appreciation of the role played by the large-scale dynamics of the extratropical atmosphere. Lack of interest in extratropical dynamics may reflect the assumption that these dynamical processes are a non-problem as far as climate modeling is concerned, since general circulation models (GCMs) calculate motions on this scale from first principles. Nevertheless, serious shortcomings in our ability to understand and simulate large-scale dynamics exist. Partly due to a paucity of standard GCM diagnostic calculations of large-scale motions and their transports of heat, momentum, ...

International Nuclear Information System (INIS)

Full text: Chemical-technology approaches allowing to intensification the prevention processes of gas hydrates formation at motion of gas-liquid stream of natural gas in system natural gas well - gas wire have been worked up. Technological regimes of treatment of gas stream have been determined. Linear correlation dependences inhibitor electrolytes contained hydrated ions with different ion radii and charges of subgroups of alkali elements with one - type electron configuration were obtained. Important physico-chemical parameters of electrolytes have been determined: activity; coefficients of activity, viscosity, diffusion; density; heat capacity; heat conductivity; surface tension and freezing-point. The features of continuous influence of inhibitory factors on process of gas flow at low temperatures and relatively high pressure differences ...

International Nuclear Information System (INIS)

When analyzing the loss-of-coolant accidents at VVER reactor NPP the problem of the effect of noncondensable gases on heat transfer in a horizontal steam generator (HSG) is gaining in importance. Based on the RELAP5/MOD3.2 computer code one analyzed the experiments to condense steam-and-gas mixture in a HSG. The calculations are shown to predict satisfactorily duration of steam generator poisoning from noncondensable gas

Energy Technology Data Exchange (ETDEWEB)

The solid particle movement in a rotary drum plays an important role in drying processes. The solid distribution in the drum affects the amount of contact surface between the solid and the gas. The retention time of solids influences the time particles can stay in contact with the gas in order to transfer heat and mass. Any heat and mass transfer model for a solid particle dryer must be able to predict solid flowrate and solid hold-up. There have been several reports in the literature regarding the modeling aspects of solid transport in dryers. If the model is developed for model-based control, it must be simple and yet represent dynamics of the system accurately. This paper addresses solid motion modeling and the effects of different variables involved in solid transport phenomena.

Energy Technology Data Exchange (ETDEWEB)

The Thomsen and Frandsen (1983) cosmological test employing the observed correlation between elliptical galaxy surface brightness and scale size in order to avoid problems due to dynamical evolution is presently extended to make use of arbitrary galaxy samples. The explicit dependence on stellar evolution is also demonstrated. On the assumption that this evolution is calculable, an equation for the deceleration parameter entirely in terms of observables is derived. The test is applied to two available samples. 25 references.

Energy Technology Data Exchange (ETDEWEB)

This meeting focussed on the study of the structure and dynamics of biological molecules, with particular emphasis on neutron and complementary methods as well as related enabling technologies. The program covered biological problems that are being addressed by neutron scattering and those where there is the potential to do so in the future. This document provides the abstracts of the different presentations. (A.L.B.)

Energy Technology Data Exchange (ETDEWEB)

The 3-dimensional (3D) extension C5G7 MOX benchmark problems were solved by CHAPLET-3D code which is based on the idea of dynamic linkage of the multi-plane method of characteristics solutions. The benchmark results are quite accurate in comparison with the reference solutions, independently of the axial solver incorporated in the CHAPLET-3D code. (author)

International Nuclear Information System (INIS)

There are several concerns which bring to consider natural gas as a viable alternative to liquid fuels in transport. First, natural gas allows the curbing of global pollution in this steadily growing industry. Indeed, decoupling greenhouse gas emissions from transport growth has become a major issue in tackling climate change. Second, a more extensive use of natural gas would relieve city air quality, which is presently at levels harmful of human health. Nonetheless, this is just one side of the coin. The other side entails building a refuelling station network, and this carries financial requirements. The financing fraction holds a pivotal role in deciding whether natural gas for automotive purposes is an efficient solution. The final aim of this work is, therefore, to compare the natural gas advantages, stemming from avoided global and local emission, with the ...

Energy Technology Data Exchange (ETDEWEB)

In response to the Clean Coal II solicitation, Bethlehem Steel Corporation (BSC) submitted a proposal to the DOE in May 1988. The proposal submitted by BSC describes a Unique integration of commercial technologies developed by Davy/Still Otto to clean coke oven gas being produced at its Sparrows Point, Maryland steel plant. This innovative coke oven gas cleaning system combines secondary gas cooling with hydrogen sulfide and ammonia removal, hydrogen sulfide and ammonia recovery, ammonia destruction and sulfur recovery to produce a cleaner fuel gas for plant use. The primary environmental benefit associated with employing this innovative coke oven gas cleaning system is realized when the fuel gas is burned within the steel plant. Emissions of sulfur dioxide are reduced by more than 60 percent. The removal, recovery and destruction of ammonia eliminates the ...

Science.gov (United States)

To quantify the opportunities for natural gas and identify technological advances needed to capture such opportunities, the mineral-wool industry was analyzed with respect to the principal companies, their capabilities, and markets. The mineral-wool industry is stable with a slightly declining market. Of its market segments, only commercial acoustic insulation (which is currently dominant) is likely to be affected by growth in the next ten years. The principal process is based on treatment of blast-furnace slags in a cupola furnace using coke as the fuel and reducing agent. Expanded use of gas, as a substitute for coke, would eliminate environmental problems and expand the latitude of suitable raw materials. The study provides insights into the mineral-wool industry and identifies factors that may constitute bases for future usage of natural gas.

International Nuclear Information System (INIS)

This book presents the papers given at a conference on two-phase flow. Topics considered at the conference included the thermal hydraulics of a feedwater pipe breakage, pressure losses, measurement of void fraction in a rod bundle, laminar filmwise condensation, natural circulation, flow models, bubble dynamics, cavitation, water hammer, and heat transfer augmentation.

CERN Document Server

Dynamic system identification

International Nuclear Information System (INIS)

A real-time two-dimensional void fraction distribution measurement of gas-liquid two-phase flow was carried out by real-time neutron radiography and real-time image processing. The JRR-3M real-time thermal neutron radiography system and a Musashi dynamic image processing system were used. Image processing methods to calculate two-dimensional and cross-sectional void fraction distributions were proposed. The void fraction distribution was calculated by non-linear processing of the neutron radiography image and displayed by pseudo-color in real-time. A simple gas-liquid two-phase flow induced by injecting gas through needles at the bottom of water pool in a rectangular vessel was tested. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The concept of using agricultural residues, especially cotton gin trash (CGT), as a fuel for a small cogeneration power plant based on fluidized bed gasification (FBG) requires that three problems be solved: (1) ash must be removed from the low calorific value (LCV) gas prior to combustion; (2) the high NO/sub x/ emissions associated with many biomass fuels must be significantly reduced; (3) a systems analyses of engineering/economic feasibility for potential applications must be developed. This paper addresses current research at TAMU pertaining to these problems.

Energy Technology Data Exchange (ETDEWEB)

The University of Groningen (RUG) has developed an expert system on cleaning of biomass producer gas. This work was carried out in close co-operation with the Biomass Technology Group B.V. (BTG) in Enschede, The Netherlands within the framework of the EC supported JOR3-CT95-0084 project. The expert system was developed as a tool for the designer-engineer of downstream gas cleaning equipment and consists of an information package and a flowsheet package. The packages are integrated in a client/server system. The flowsheeting package of the expert system has been designed for the evaluation of different gas cleaning methods. The system contains a number of possible gas cleaning devices such as: cyclone, fabric filter, ceramic filter, venturi scrubber and catalytic cracker. The user can select up to five cleaning steps in an arbitrary order for his specific gas cleaning ...

International Nuclear Information System (INIS)

An artificial neural network can be used as an intelligent controller to control non-linear, dynamic system through learning. It can easily accommodate non-linearities and time dependencies. Most common multi-layer feed-forward neural networks have drawbacks of large number of neurons and hidden layers required to deal with complex problems and require large training time. To overcome these drawbacks, a generalized neuron based non-linear controller has been developed and illustrated as a power system stabilizer. Studies on a five-machine power system show that the proposed controller can significantly improve the dynamic performance and provide good damping of the power system over a wide operating range.

CERN Document Server

In this paper we present results of using parallel supercomputers to simulate beam dynamics in next-generation high intensity ion linacs. Our approach uses a three-dimensional space charge calculation with six types of boundary conditions. The simulations use a hybrid approach involving transfer maps to treat externally applied fields (including rf cavities) and parallel particle-in-cell techniques to treat the space-charge fields. The large-scale simulation results presented here represent a three order of magnitude improvement in simulation capability, in terms of problem size and speed of execution, compared with typical two-dimensional serial simulations. Specific examples will be presented, including simulation of the spallation neutron source (SNS) linac and the Low Energy Demonstrator Accelerator (LEDA) beam halo experiment.

Energy Technology Data Exchange (ETDEWEB)

A dynamic control rod worth measurement was performed for control bank D, C, B, and A of Yonggwang unit 1 cycle 14 during its low power physics test. MASTER was used for three-dimensional core kinetics calculations required to convert excore detector signal into static rod worth, using the same modeling and cross sections as ANC which was used for the core static design. A signal curve fitting method was proposed to solve a low signal problem due to large amount of rod worth, which leads to the distortion of resulting static worth. The static worths measured in this test well agreed with the predicted worth of design within {+-}15% which is a test requirement of rod worth measurement.

British Library Electronic Table of Contents (United Kingdom)

Forced harmonic vibration of a non-uniform elastic beam with attached dynamic vibration absorbers (DVA) is studied. Analytical approximation of the solution is obtained by the functional perturbation method (FPM). The problem has application to cutting tools operations where the resistance of the tool holder against regenerative chatter can be enhanced by optimizing the real part of the frequency response function (FRF). A test case of a beam with step-like heterogeneity and single DVA at the tip shows that the FPM solution is very accurate for up to ?40 percent deviation in both stiffness and mass density. Using the analytical results and Sims approach, optimal DVA tuning is found for each set of beam heterogeneity parameters by solving a set of nonlinear algebraic equations numer...

Energy Technology Data Exchange (ETDEWEB)

Restructuring of power system has changed the traditional planning objectives and introduced challenges in the field of Transmission Expansion Planning (TEP). Due to these changes, new approaches and criteria are needed for transmission planning in deregulated environment. Therefore, in this paper, a dynamic expansion methodology is presented using a multi-objective optimization framework. Investment cost, congestion cost and reliability are considered in the optimization as three objectives. To overcome the difficulties in solving the non-convex and mixed integer nature of the optimization problems, a Non-Dominated Sorting Genetic Algorithm (NSGA II) approach is used followed by a fuzzy decision making analysis to obtain the final optimal solution. The planning methodology has been demonstrated on the IEEE 24-bus test system and north-east of Iran national 400 kV transmission grid to show the feasibility and capabilities of the proposed ...

Energy Technology Data Exchange (ETDEWEB)

The theory and application of the optimal control of linear systems to stabilize or improve the system stability is well known. For an optimal linear regulator design, the arbitrariness involved in the parameters of the cost function always affects the final control law and the closed-loop system poles which decide the system dynamic characteristics. A new approach, 'The inverse problem approach' has been developed to overcome this difficulty. The system so designed will have preassigned closed-loop poles and the resulting closed-loop system performance can be ensured. In this paper the inverse problem approach for optimal regulator design is applied to the power system stabilizer (PSS) design for single-machine infinite-bus systems. The results show that, as far as the linearized model is concerned, systems designed by the inverse problem approach have better closed-loop performance ...

British Library Electronic Table of Contents (United Kingdom)

The transport of liquid water and gaseous reactants through a gas diffusion layer (GDL) is one of the most important water management issues in a proton exchange membrane fuel cell (PEMFC). In this work, the liquid water breakthrough dynamics, characterized by the capillary pressure and water saturation, across GDLs with and without a microporous layer (MPL) are studied in an ex-situ setup which closely simulates a real fuel cell configuration and operating conditions. The results reveal that recurrent breakthroughs are observed for all of the GDL samples tested, indicating the presence of an intermittent water drainage mechanism in the GDL. This is accounted for by the breakdown and redevelopment of the continuous water paths during water drainage as demonstrated by Haines jumps. For GDL ...

International Nuclear Information System (INIS)

This progress report concerns work completed or initiated since our last report in October of 1980. We have performed experiments in two major areas: photodissociation of organic cations to study the competition between isomerization and fragmentation; and, low energy proton transfer reactions of HCO"+ with selected neutrals. The former area provides a sideline to our combustion studies of proton transfer in hydrocarbon flames, but the question of energy transfer in highly excited gas phase ions impacts directly upon questions closely related to the fate of ions in combustion. The latter area, currently in progress, focuses upon the dynamics of biomolecular reactions of direct relevance to combustion.

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new application in dynamic voltage control based on an older method of voltage regulation. The resulting method is suitable for adoption inn multi-unit pumped storage plants. Inherent operation characteristics of pumped storage plants in the pumping mode can created visible load rejection overvoltages on the transmission and the nearby distribution networks and cause customer complaints. This paper proposes a method in which the on-line units' excitation system impedance compensators are utilized to reduce the magnitude of these overvoltages. This paper presents the theoretical background, computer simulation results, and the field test results at the Pacific Gas and Electric Company's Helms Pumped Storage Plant. This paper should be of interest in the areas of power system planning as well as power system operation.

Energy Technology Data Exchange (ETDEWEB)

An adaptive contingency selection process is set up which produces outage lists in order to guarantee on-line network security control. The quality index system used so far did not detect and reveal all critical variables due to observation problems in the mapping of two functions. The new process uses the results of the outage simulation computing of the system status just past for the drawing up of an up-to-date outage list. A linear correcting function transform the G{sub 2}-values of the standard quality index method - which still incorporate the observation problem effect - into improved values G. Studies which use data from realstic high-voltage networks prove that the detection of critical variables is far superior to ordinary methods. (orig.).

CERN Document Server

The effective approach to quantum dynamics allows a reformulation of the Dirac quantization procedure for constrained systems in terms of an infinite-dimensional constrained system of classical type. For semiclassical approximations, the quantum constrained system can be truncated to finite size and solved by the reduced phase space or gauge-fixing methods. In particular, the classical feasibility of local internal times is directly generalized to quantum systems, overcoming the main difficulties associated with the general problem of time in the semiclassical realm. The key features of local internal times and the procedure of patching global solutions using overlapping intervals of local internal times are described and illustrated by two quantum mechanical examples. The choice of time is tantamount to a choice of gauge at the effective level and changing the clock is, therefore, equivalent to a gauge transformation. This article complements ...

International Nuclear Information System (INIS)

Oil and gas production and processing operations sometimes cause naturally occurring radioactive materials (NORM) to accumulate at elevated concentrations in by-product waste streams. The sources of most of the radioactivity are isotopes of "2"3"8U and "2"3"2Th series, which are naturally present in the subsurface formations from which oil and gas are produced. NORM waste may cause problems in the operations of installations by plugging perforations, clogging tubular and valves then restricting flow. Therefore, plants or equipment have to be refurbished and decontaminated before reuse to avoid radioactive waste or surface contaminated object. There are two options for safe disposal of scale and sludge produced from NORM Descaling Facility : 1- Injection into an abandoned production well. 2- The construction of a near surface depository. These options are assumed to be environmental friendly disposal options. (author)

Science.gov (United States)

As coal becomes more and more important as a power plant fuel in this time of energy shortage and the combustion of high-sulfur coals that would impair air quality, efforts have been made to devise efficient processes to control sulfur dioxide emission. Besides desulfurization before combustion, flue gas desulfurization is considered the most promising method that could also be applicable to all other fossil fuels. In this article, the flue gas desulfurization processes are briefly reviewed, and processes with highest use and with high potential for future use are compared from technical and economical points of view. In the selection of a desulfurization process, it is very important to consider the capacity of the plant, fuel type and fuel-to-sulfur ratio, availability and price of the reagent to be used, type, price, and market of side products, disposal problems of wastes, and environmental factors.

International Nuclear Information System (INIS)

Gyrokinetic particle simulation of edge pedestal formation and plasma rotation dynamics will be presented, and compared with experimental observations. Realistic tokamak edge geometry is used which include separatrix/X-point and material wall from EFIT g-eqdsk data. In order to handle adequately the spatially inhomogeneous electric potential in the scrape-off region, the full-f electron technique is used, in addition to the full-f ions. Monte Carlo neutral particles with wall recycling coefficient will be included self-consistently with the plasma kinetics. Ion-ion Coulomb collisions will be particle, momentum and energy conserving. Energy source for the pedestal and scrape-off plasmas is the heat flow from the core plasma, and the particle source is the ionization of the neutral atoms which are either wall recycled and/or gas puffed. The simulation will be self-consistent with the first principles nonlinear neoclassical and (electrostatic so ...

Energy Technology Data Exchange (ETDEWEB)

The investigations of lignite hydroliquefaction were aimed at improving reaction control in order to minimize residue and gas portion and hence increase the oil yield. To reach this goal, the process parameters were optimized and various catalysts tested for use in sump phase hydrogenation. Detailed investigations were also carried out on the problem of calcium carbonate agglomeration and the maceral decomposition behaviour of different lignite samples under hydrogenation conditions.

CERN Document Server

A study on the aging process of gas detectors was presented. How the development of more performing but delicate detectors, the use of faster but aggressive gases, and the need to cover large areas, led to unexpected problems was discussed. Various methods for curing aged detectors were also highlighted. (Edited abstract) 37 Refs.

Energy Technology Data Exchange (ETDEWEB)

This paper presents a systematic approach to the automatic determination of the evolution of the rigid-plastic structural response caused by a proportional or single parameter pressure loading which varies with time in a monotonic non decreasing fashion. The frame structure is envisaged as a network, and the fundamental vectorial conditions characterising its behaviour at any instant of time are combined in a consistent manner. By considering the level of the pressure loading to be a single load parameter ranging monotonically from zero to infinity, the structural governing system may be regarded as a parametric linear complementary problem. (author). 13 refs., 2 figs.

British Library Electronic Table of Contents (United Kingdom)

Introduction Gastrointestinal bleeding is a common life-threatening problem, causing significant mortality, costs and resource allocation. Its management requires a dynamic multidisciplinary approach that directs diagnostic and therapeutic priorities appropriately. Materials and methods Articles published within the past 15 years, related to gastrointestinal bleeding, were reviewed through MEDLINE search, in addition to current guidelines and standards. Results Decisions of ICU admission and blood transfusion must be individualized based on the extent of bleeding, hemodynamic profile and comorbidities of the patient and the risk of rebleeding. A secure airway may be required to optimize oxygenation and to prevent aspiration. Doses of induction agents must be reduced due to the changes in v...

Energy Technology Data Exchange (ETDEWEB)

We decided to investigate first the interaction of hydrogen with the 4d transition-metal series, with the first element being hcp Y. Because of the recent development of soft pseudopotentials, we chose to use the plane wave basis set to carry out the calculation. Since problems had been associated with the slow convergence in transition metals, we first tested the computational methods by studying the structural properties of Y; results were encouraging. We started the calculation of YH{sub x} with hydrogen occupying different interstitial sites.

Energy Technology Data Exchange (ETDEWEB)

The outward radial expansion of a free liquid annulus is a common problem of both earlier and current ICF blanket design. Whether the annulus fractures or not depends on the internal pressure and surface stability. In this paper a model based on incompressible cylindrically symmetric flow is used to get a theoretical solution similar to that of the Rayleigh's solution for bubble dynamics. The pressure inside the annulus is found positive all time but the peak is lowering during the expansion. Besides, both surfaces are Taylor stable during such motion. Thus, it is concluded that an annulus in outward radial motion will not cavitate or breakup.

CERN Document Server

It is well known that for ergodic channel processes the Generalized Max-Weight Matching (GMWM) scheduling policy stabilizes the network for any supportable arrival rate vector within the network capacity region. This policy, however, often requires the solution of an NP-hard optimization problem. This has motivated many researchers to develop sub-optimal algorithms that approximate the GMWM policy in selecting schedule vectors. One implicit assumption commonly shared in this context is that during the algorithm runtime, the channel states remain effectively unchanged. This assumption may not hold as the time needed to select near-optimal schedule vectors usually increases quickly with the network size. In this paper, we incorporate channel variations and the time-efficiency of sub-optimal algorithms into the scheduler design, to dynamically tune the algorithm runtime considering the tradeoff between algorithm efficiency and its robustness to ...

Energy Technology Data Exchange (ETDEWEB)

Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based upon these changes we estimate diffusive travel times associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage an approach based upon travel times, as opposed to one based upon the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. We apply the formulation to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is approximately ...

Energy Technology Data Exchange (ETDEWEB)

The Synthesis Gas From Manure (SGFM) pilot plant was constructed at Texas Tech University to evaluate the gasification of cattle feedlot manure. A study of gas yield and composition as a function of operating conditions was performed. This report presents the results of a comparison of feedstocks other than manure in the pilot plant. Oak sawdust was the superior feedstock tested in terms of both gas yield and operability. Corn stover and mesquite were comparable and presented some handling problems. Cotton gin trash was unacceptable due to low-temperature ash fusion in the reactor. The gas yield from oak sawdust varied from 0.8 to 1.7 1/gm DAF feed at average temperatures of 650 to 770/sup 0/C. The gas contained approximately 15% hydrogen and 40% carbon monoxide by volume. It also contained 5 to 8% methane and 2 to 5% ethylene. All of these results were obtained ...

Science.gov (United States)

Under support from the French Space Agency (CNES), a 3D+t dusty-gas model of Comet 67P/Churyumov-Gerasimenko is being developed, to compute, from the first 2014 Rosetta orbital data, the aerodynamic forces exerted on the Rosetta orbiter and on the descent lander. We report the recently developed dust dynamics part of the code. The multi-species (presently H2O and CO) gas code is optimized in terms of computational speed owing to the use of two complementary methods: (a) 3D+t Direct Simulation Monte Carlo (DSMC) runs in the non-equilibrium regions adjacent to the surface and very distant from it, and (b) solutions of the Navier-Stokes equations in-between. The model is used presently using Lamy et al. (Space Sci. Rev., 2007, 128, 23) coarse information on 67P nucleus shape and rotation, and a range of possible gas production rates Q for the early Rosetta observations at rh 3 AU (Q 1026 - 1027 s-1). In ...

Energy Technology Data Exchange (ETDEWEB)

The biological treatment process was selected by Gaz de France (GDF), the French national gas utility, for the de-pollution of an old gas works where the main pollutants are coal tars containing polycyclic aromatic hydrocarbons. Microorganism-based biological treatment techniques may involve bio-reactors, static ground knolls (where oxygen is brought through drains) and dynamic knolls (where oxygenation is carried out by turning up the soil). Issues on sampling, sorting, process testing, site preparation, process control, etc. are reviewed

British Library Electronic Table of Contents (United Kingdom)

Using the Galaxy as an example, we study the effect of Formula Not Shown force on the rotational curves of gas and plasma in galaxies. Acceptable model for the galactic magnetic field and plausible physical parameters are used to fit the flat rotational curve for gas and plasma based on the observed baryonic (visible) matter distribution and Formula Not Shown force term in the static MHD equation of motion. We also study the effects of varied strength of the magnetic field, its pitch angle and length scale on the rotational curves. We show that Formula Not Shown force does not play an important role on the plasma dynamics in the intermediate range of distances 6?12?kpc from the centre, whilst the effect is sizable for larger r (r?15?kpc), where it is the most crucial.

Energy Technology Data Exchange (ETDEWEB)

Sub sea pipeline construction at oil and gas fields, with high concentration of on-bottom facilities, becomes more difficult when mooring operations and pipeline approach to a congested platform have to be performed. One method that has often been applied in Brazil is the so-called 'DP (Dynamic Positioning) pull-in', where PETROBRAS owned pipelay Barge, BGL-1, is moored away from the congested area, while a DP anchor handler pulls the rigid pipeline from BGL-1 to a target near the platform. The method was conceived to avoid mooring operations near the congested platforms as well as to minimize risks due to the pipeline initiation process. Inside the congested area the initiation with aid of a 'dead-man' anchor on the sea bottom, which would be a more conventional solution, becomes impossible in most cases. This paper will discuss the engineering work required to perform the 'DP pull-in' as ...

Energy Technology Data Exchange (ETDEWEB)

Sessions covered economic and management, advance control technologies (including pulverized coal dynamic balancing-activator and control strategy by B. DeMarcy and X.Ollat), nuclear technologies, environmental (including purge considerations for seasonal SCR systems by D.P. Evely, NOx and heat rate supervisory control at NRG-Huntley operations by G Lange, comparison of gypsum dewatering technologies at flue gas desulfurization plants by B.A. Perlmutter, beta gauge particulate monitoring by J.L. Arnold), improving performance at nuclear power plants, network security, and emerging applications.

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)

This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by ...

Science.gov (United States)

Analysis of ENSO Dynamics and ThermoDynamics in the Western Pacific Warm Pool - An Application of Multi-Sensor Satellite Observations. ...

Energy Technology Data Exchange (ETDEWEB)

The gas-solid reaction and breakthrough curves in the fixed-bed reactor are of great importance, and being influenced by a number of factors makes the prediction of these factors a difficult problem. In this study, the reaction rate between solid sorbents and hydrogen chloride gas at high temperature was first investigated. On the basis of a fixed-bed reactor, the experimental results were analyzed by the shrinking core model of diffusion and surface chemical reaction control. The results showed that reaction rates of two sorbents with hydrogen chloride gas were controlled by the combination of the surface chemical reaction and diffusion of product layers, and the reaction rates nearly keep constant within 15 h of the initial reaction period and then decrease gradually. The results of the breakthrough curves show that solid sorbents in the fixed-bed reactor are capable of reducing the HCl level to ...

Energy Technology Data Exchange (ETDEWEB)

This is a report on modification of a locomotive diesel engine to a dual-fuel engine to determine if the dual fuel engine in railway service will provide high performance, lower fuel and maintenance costs. After the locomotive was modified and the new governor and linkage were installed by General Motors at the BN's Northtown Diesel Shop near Minneapolis, the locomotive went through startup procedures. General Motors participated in startup. Some calibration, adjustments and minor piping changes were required but in general the problems encountered in startups were quite insignificant. The locomotive was connected to the load box (static test) during startup and at 720 RPM exceeded the required output for this test as established by the parties. Operation on straight oil over the range from idle through No. 8 throttle notch and on dual fuel from No. 5 through No. 8 throttle notch was smooth as was the transfer from oil to gas and from ...

Energy Technology Data Exchange (ETDEWEB)

North Slope of Alaska has huge oil deposits in heavy oil reservoirs such as Ugnu, West Sak and Shrader Bluff etc. The viscosity of the last two reservoir oils vary from {approx}30 cp to {approx}3000 cp and the amount in the range of 10-20 billion barrels. High oil viscosity and low formation strength impose problems to high recovery and well productivity. Water-alternate-gas injection processes can be effective for the lower viscosity end of these deposits in West Sak and Shrader Bluff. Several gas streams are available in the North Slope containing NGL and CO{sub 2} (a greenhouse gas). The goal of this research is to develop tools to find optimum solvent, injection schedule and well-architecture for a WAG process in North Slope shallow sand viscous oil reservoirs. In the last quarter, we have developed streamline generation and convection subroutines for miscible gas injection. The ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of the project is to further develop a Danish natural gas reformer system including optimisation of subsystems and the overall system consisting of a natural gas reformer and fuel cell CHP generator. This will contribute to the evaluation of to what extend Denmark shall develop small reformer units for PEM fuel Cells. In the project a reformer system with a high degree of automatic control has been build that fulfils the CHP requirements to operation time, dynamics etc. This work, with a FP05 reformer unit, has given valuable results concerning the possibilities and limitations of the reformer technology for CHP usage. It is important that the reformer and fuel cell units are designed with matching yields to optimise efficiency, turn-down start-up time etc. The burner that delivers heat for the steam reaction shall be able to use natural gas as fuel. This gives the possibility of using ...

Energy Technology Data Exchange (ETDEWEB)

This paper explains technologies for turbo chargers used in light cars. Light car engine turbo chargers have been given various improvements responding to needs of the market. Since ball bearings have less mechanical loss than sliding bearings, and enhances greatly the turbo efficiency, they are used in some high performance engines of light cars. While the conventional ball bearing has used high hardness bearing steel, the new standard cars started using ceramic ball. The currently used light car gasoline engines are divided into two kinds, serial three-cylinder type and serial four-cylinder type, either having merits and demerits. The new twin entry turbo developed by IHI arranges divided exhaust gas ports above and below to simplify the manifold shape, and realizes smooth flow by twisting the exhaust gas flow path inside the turbine housing. This makes the dynamic pressure of the exhaust gas more ...

International Nuclear Information System (INIS)

We have developed a photon accumulated laser mass spectrometer that enables us to identify isomers of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran. This system is comprised of a high temperature (230 deg. C) pulsed gas injector (PGI), multimirror multipath system (MMS), and the conventional time-of-flight mass spectrometer. The PGI induces the formation of a choked supersonic jet gas pulse that cools down to a temperature to restrain fragmentation and reduces vibrational and rotational thermal noises. The results suggest that the excited lifetime numbers and fragment dynamics of these species change completely with jet cooling of molecules. The MMS enhances the soft ionization efficiency (by a factor of 1000 over a single path system) through photon accumulation by extending the irradiation duration (to about 40 ns) and volume, and it further minimizes fragmentation by carefully controlling the laser ...

Energy Technology Data Exchange (ETDEWEB)

The deexcitation of quasi-projectiles (QP) released in binary Au on Au collisions as been studied from 60 to 100 MeV/u. Bimodality between two different decay patterns has been observed for intermediate violence collisions. The main experimental result is that the system jumps from one mode to the other on a narrow range of energy deposit and/or impact parameter. The sorting of the events (according to the violence of the collision) has been provided by the perpendicular energy of the light charged particles emitted on the quasi-target side. Such a sorting prevents spurious autocorrelation effects between the sorting variable and the observed mechanism. The two modes of the QP decay correspond on the one side to residue or fission fragments production, and on the other side to the multifragmentation channel. A detailed study has been performed in order to try to establish the origin of the observed bimodality in disentangling dynamical or geometrical effects from ...

International Nuclear Information System (INIS)

The dynamic response of thin liquid storage tanks to earthquakes is a very complicated phenomenon, because it can be highly non linear. Among others, one can meet material and geometric non linearities of the tank shell leading eventually to static or dynamic buckling non linear behavior of anchor bolts, contact non-linearities due to the uplift of the tank base and to the unilateral character of the fluid pressure on the shell and high amplitude fluid oscillations. Moreover, linear or non linear soil structure interaction affects considerably the response of the fluid structure system under consideration. In this paper we focus attention on problems related only to the base uplift and anchors plastification. We study a tank similar to the Hualien project tank, but we neglect the soil structure interaction. The studied tank is representative of medium height to radius ratio ratio tanks with relatively thick bottom plate. ...

Energy Technology Data Exchange (ETDEWEB)

The intent of this manual is to provide inspectors from Federal and state environmental agencies with information regarding the problems that plague lime/limestone slurry flue-gas desulfurization (FGD) systems that will aid them in their inspections and performance evaluations of these systems with respect to compliance with the emission standards that have evolved since the passage of the 1970 Clean Air Act. A unique feature of the manual is its structure as a tool, or working document, which will accompany the inspector on each plant inspection. Thus, the document is presented in user friendly fashion and tailored to provide practical information for its intended use--to assist in the systematic inspection of an FGD system to determine present and future compliance status. The approach entails the use of nomographs, checklists, matrices, simplified diagrams, cross-referencing, and indexing of textual information, and the presentation of ...

Science.gov (United States)

The report gives background design data for a specific copper smelter. The data is sufficiently detailed to allow air pollution control system engineering studies to be conducted. These studies will be concerned primarily with lean SO/sub 2/ streams that currently are not being captured. Physical layout of the smelter and the surrounding area is presented, along with existing control equipment. Ductwork that would be considered for future system tie-in is defined. Emissions from operating equipment, gas flow rates, temperatures, sulfur balance, and a process flow sheet are included. Utilities, stack dimensions, footing requirements, and solid waste handling are defined. Available area for new control equipment, gas characteristic variation, and potential new control equipment installation problems are discussed. Portions of this document are not fully legible. (GRA)

Energy Technology Data Exchange (ETDEWEB)

Crankshafts of the pearlitic-sorbitic nodular cast iron type JUS NL.80 (similar to DIN GGG-80) heat treated to get a tensile strength of 820-900 GPa (i.e. a Vickers hardness of 268-295 HV) were plasma and ammonia gas nitrided. The glow discharge plasma nitriding was performed for 20 h at about 500degC in a gas mixture of 55% N{sub 2} and 45% H{sub 2}. The gas nitriding was performed for 28 h at 510degC in the ammonia gas. Evaluation of the nitrided surfaces was conducted by optical microscopy, X-ray diffractometry and microhardness measurements. Journal and crank pin dimensions and surface roughness were measured both before and after nitriding. Bending fatigue testing of crankshafts was performed using a fatigue testing rig. The fatigue limit was evaluated at 5.0x10{sup 6} cycles. The fractures happened at the transition radius of the journal with cracks starting beneath the nitrided layer. It was ...

International Nuclear Information System (INIS)

Total EU (and Norway) emissions of CO_2 from thermal power generation were some 950 million tonnes in 1990, the Kyoto agreement reference level. An ongoing research project, the GESTCO project, will provide the first documentation that, for the emission sources within the selected key areas, sufficient geological storage capacity is available for at least 30 years and possibly much longer. Cost of energy will obviously increase, but it is anticipated that electricity production cost price will be comparable to that of renewables. It would further have major implications for the European power generating industry which today is totally dominated by fossil fuel combustion with enormous emissions problems. The identification and siting of subsurface CO_2 storage capability can be expected to have considerable effect on the planning for and future siting of fossil fuel plants. In Norway there are plans to build several major, coastally sited, natural ...

Energy Technology Data Exchange (ETDEWEB)

The industrial policy of fine ceramics which is one of the new material expected to solve energy/environmental problem, is described. Fine ceramics are possessed with the characteristics like surpassing electromagnetic properties, heat resistance, high strength, etc. and its use as highly efficient power generation plant material, functional material for various sensors/electronic, and activation of existing industries are cited. As for the reclamation of global environment, promotion of saving energy in a global scale, development of innovative environmental technology and increase of carbon dioxide absorption source are described. Furthermore, research and development work in Japan on global environmental industrial technology for 1992 to 1993, new sunshine project and technical developments relating to fine ceramics are explained. As for the results of research and development, the results from the case study of 300kw type gas turbine are ...

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Interference between the crossover leg of the Reactor Coolant System(RCS) and the Pipe Whip Restraints(PWR) has brought a degradation issue of the integrity of the Reactor Coolant System in Westinghouse type Nuclear Power Plants(NPPs) of Korea. According to the gap inspection carried out during planned overhaul (year 2000), interference between the crossover leg and the PWR was found in each RCS loop. This plant has had the high vibration problem on the RC pump 'B'. The reason for the high vibration in the RC pump 'B' had been massively surveyed and it was found that the crossover leg of RCS contacted with the PWR in hot condition. Since the contact between the crossover leg and the PWR changes the dynamic characteristics of the piping system for the RCS, this is considered as one reason for the high vibration. And a possibility of overstress on the crossover leg due to the contact with the PWR should be ...

Energy Technology Data Exchange (ETDEWEB)

Describes the wastes produced and the waste disposal methods used at BEWAG power plants. Wastes covered include fly ash, fluidized bed ash, gypsum from flue gas desulfurization and evaporation residues. Disposal methods include using ashes and gypsum to make building materials. Despite many years of experience in the utilization and disposal of residues from coal-fired power stations BEWAG have not encountered any disposal problems. 5 tabs.

Energy Technology Data Exchange (ETDEWEB)

Radian Corporation was contracted to investigate duct injection and ESP phenomena in a 1.7 MW pilot plant constructed for this test program. This study was an attempt to resolve problems found in previous studies and answer remaining questions for the technology using an approach which concentrates on the fundamental mechanisms of the process. The goal of the study was to obtain a better understanding of the basic physical and chemical phenomena that control: (1) the desulfurization of flue gas by calcium-based reagent, and (2) the coupling of an existing ESP particulate collection device to the duct injection process. Process economics are being studied by others. (VC)

International Nuclear Information System (INIS)

The current status of research and development in the realm of physics and technology of collective ion acceleration in systems with a virtual cathode (VC) is reviewed. Three major acceleration methods and devices developed on their basis are considered: reflex triodes and their modifications, gas-filled vircators, and vacuum vircators with a Luce diode. Experimental data are outlined and the principal physical models interpreting these data are described. New ion acceleration techniques whose realization involves the production and disappearance of the VC are also discussed. All methods of collective ion acceleration are compared and the possible ways for the further development of this promising scientific field are highlighted. (reviews of topical problems)

Energy Technology Data Exchange (ETDEWEB)

This handbook covers the general area of lubrication and tribology in all its facets: friction, wear lubricants (liquid, solid, and gas), greases, lubrication principles, applications to various mechanisms, design principles of devices incorporating lubrication, maintenance, lubrication scheduling, and standardized tests; as well as environmental problems and conservation. The information contained in these two volumes will aid in achieving effective lubrication for control of friction and wear, and is another step to improve understanding of the complex factors involved in tribology. Both metric and English units are provided throughout both volumes.

Energy Technology Data Exchange (ETDEWEB)

Naval Petroleum Reserve No. 3 (NPR-3), also known as Teapot Dome, is a government-owned oil field in Natrona County, Wyoming. It is an asymmetrical anticline located on the western edge of the Powder River Basin, just south of the Salt Creek Anticline. Production started in 1922, and today the field is a marginally economic stripper field with average production of less than 3 BOPD (0.5 m{sup 3}/D) per well. Total field production is about 1,800 BOPD (286 m{sup 3}/D). The Second Wall Creek Formation was waterflooded from 1979 until June 1992 with poor results due to the extensive natural fracture system in this sandstone unit. Since water injection ceased, reservoir pressure has declined to very low levels. Liquids extraction and reinjection of the gas produced from high-GOR wells along the gas-oil contact continues, but the average gas cap pressure has fallen to approximately 150 psi (1.03 MPa) from an original pressure of ...

International Nuclear Information System (INIS)

An original dc double anode plasma torch which provides a long-time and highly stable atmospheric plasma jet has been devised for the purpose of hazardous waste treatment. The arc fluctuations and dynamic behaviour of the argon and argon-nitrogen plasma jets under different operating conditions have been investigated by means of classical tools, such as the statistic method, fast Fourier transform (FFT) and correlation analysis. In our experiments, the takeover mode is identified as the fluctuation characteristic of the argon plasma jet while the restrike mode is typical in the argon-nitrogen plasma dynamic behaviour. In the case of pure argon, the FFT and correlation calculation results of electrical signals exhibit the only characteristic frequency of 150 Hz, which originates from the torch power and is independent of any change in the operating conditions. It indicates that the nature of fluctuations in an argon plasma jet is mainly induced ...

British Library Electronic Table of Contents (United Kingdom)

The integration of the environmental problem in the design of industrial products leads us to incorporate vegetal fibres and recycled polymers into composite materials. The aim of this work is to study the behaviour and the environmental interest of a recycled PP/hemp fibre after several injection cycles. The mechanical and rheological behaviour of recycled PP/hemp composite was first studied by using tensile, dynamical mechanic analysis and rheological measurements. Then, to better understand the influence of the recycling, a morphology study was carried out on composites by using optical and electron microscopy. Finally, we investigated the environmental advantages of our composite thanks to a simplified environmental assessment. Our results highlighted the environmental interest of usin...

British Library Electronic Table of Contents (United Kingdom)

Customer Relationship Management (CRM) systems can help organizations manage customer interactions more effectively. Like many new technologies, CRM has been accompanied by vendor hype and stories of implementation failure. Work on critical success factors (CSFs) should encourage more appropriate implementation practice; however many CSF studies conclude with a list of factors but provide little further guidance. In particular, there is a need for stronger theoretical models of the entire CRM innovation process which can be used by managers to understand better the underlying causes of success and failure. This paper adopts a novel approach to this problem by firstly developing a conceptual model of CRM innovation and then converting this model into a dynamic simulation model. Some early s...

Energy Technology Data Exchange (ETDEWEB)

Results of discrete element method (DEM) simulation and magnetic resonance imaging (MRI) experiments are compared for monodisperse granular materials flowing in a half-filled horizontal rotating cylinder. Because opacity is not a problem for MRI, a long cylinder with an aspect ratio {approximately}7 was used and the flow in a thin transverse slice near the center was studied. The particles were mustard seeds and the ratio of cylinder diameter to particle diameter was approximately 50. The parameters compared were dynamic angle of repose, velocity field in a plane perpendicular to the cylinder axis, and velocity fluctuations at rotation rates up to 30 rpm. The agreement between DEM and MRI was good when the friction coefficient and nonsphericity were adjusted in the simulation for the best fit. {copyright} {ital 1998 American Institute of Physics.}

CERN Document Server

We investigate opportunistic cooperation between unlicensed secondary users and legacy primary users in a cognitive radio network. Specifically, we consider a model of a cognitive network where a secondary user can cooperatively transmit with the primary user in order to improve the latter's effective transmission rate. In return, the secondary user gets more opportunities for transmitting its own data when the primary user is idle. This kind of interaction between the primary and secondary users is different from the traditional dynamic spectrum access model in which the secondary users try to avoid interfering with the primary users while seeking transmission opportunities on vacant primary channels. In our model, the secondary users need to balance the desire to cooperate more (to create more transmission opportunities) with the need for maintaining sufficient energy levels for their own transmissions. Such a model is applicable in the emerging area of cognitive ...

Energy Technology Data Exchange (ETDEWEB)

Selective catalytic reduction (SCR) is a method of reducing the emissions of nitrogen oxides into the atmosphere. Peerless Manufacturing Co. specialises in designing and building SCR systems. The company uses fluid flow modelling to design systems, creating physical and/or numerical flow models to normalise the flow and eliminate potential problems. Computational fluid dynamics (CFD) is used to visualise fluid flow within SCR units and other types of equipment involving phase separators, air intake systems etc. An example is given of use of the commercial CFD code FLUENT to create a full-scale model of an SCR unit so its design could be modified for optimum performance. 1 fig., 1 photo.

CERN Document Server

The main topic of this thesis concerns efficient algorithms for the calculation of determinants of the kind of matrix typically encountered in lattice QCD. In particular an efficient method for calculating the fermion determinant is described. Such a calculation is useful to illustrate the effects of light dynamical (virtual) quarks. The methods employed in this thesis are stochastic methods, based on the Lanczos algorithm, which is used for the solution of large, sparse matrix problems via a partial tridiagonalisation of the matrix. Here an implementation is explored which requires less exhaustive treatment of the matrix than previous Lanczos methods. This technique exploits the analogy between the Lanczos tridiagonalisation algorithm and Gaussian quadrature in order to calculate the fermion determinant. A technique for determining a number of the eigenvalues of the matrix is also presented. A demonstration is then given of how one can improve ...

Energy Technology Data Exchange (ETDEWEB)

Accidents of free-rolling cars against walls with friction are special cases of the general problem of the dynamic behavior (elastic or plastic) of car motion. Using particle modeling of the car body it is shown that large rotations, contact friction and plastic deformations can be computed. Because of the limitations of FEM it is necessary to model the car as a system of mass points connected by central force systems which are non-linear. The wall is formulated as a rigid body producing constraints for the contacting particles, while the contact force is given by the defined force system. Every contacting particle produces a plastic impact on the wall. The friction force is proportional to the contact force and lies in the direction of the sliding velocity on the wall. Time integration is carried out using a second order Gear method. ((orig.))

Energy Technology Data Exchange (ETDEWEB)

Problems can sometimes occur during the construction of cast in-situ concrete piles. These foundations are formed by drilling a substantial hole into the ground and subsequently filling it with steel reinforcement and wet concrete. Several well-documented cases exist where concrete has not filled the hole and substantial voids have been left in the apparently completed pile. A theory has been developed by which it is possible to identify the nature, size and position of a finite defect within a suspect pile. The technique is based on the concept of receptances, and requires information obtained from vibration tests performed on piles after the concrete has hardened, and the nominal dimensions and material properties of the pile. The application of the theory is demonstrated using data relating to a pile with a known defect. The theory described in this paper ignores the effect of the surrounding soil; this can be included by further development of the theory.

International Nuclear Information System (INIS)

The dynamics of a cluster-type system formed by constant total number of molecules, M, is studied when clusters change their sizes by nearest-size transitions (the Szilard model) with time-dependent boundary conditions and non-zero initial cluster size distribution. We compare these results to those reported previously, when non-stationary cluster size distribution was considered under the condition that only monomers are present in the system at the initial moment t=0, and describe the effect of arbitrary pre-existing clusters on the time evolution of the interacting clusters with different sizes, n. The average group size problem is also solved, and the process of relaxation in the system is studied. authors)

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An approximate analysis based on the virtual work technique, which was used to determine the effect of fluid velocity on the response frequency of a simply supported pipe, resulted in the following conclusions: (1) the critical fluid velocity at which the system becomes statically unstable is 129.5 ft/s; (2) the natural frequency of the pipe decreases as the fluid velocity increases; (3) higher flow rates increase the dynamic coupling of the system, making it much more susceptible to external excitation; (4) as the critical frequency approaches zero and the fluid velocity approaches the critical value, the amplitude becomes greater (though in an actual pipe, damping effects will limit the amplitude somewhat); and (5) the virtual work technique is a convenient method for approximating solutions to most non-linear vibration problems, giving results that are satisfactory for engineering-design purposes.

CERN Document Server

The stellar disc kinematics in a sample of fifteen intermediate- to late-type edge-on spiral galaxies are studied using a dynamical modeling technique. The sample covers a substantial range in maximum rotation velocity and deprojected face-on surface brightness and contains seven spirals with either a boxy- or peanut-shaped bulge. Dynamical models of the stellar discs are constructed using the disc structure from $I$-band surface photometry and rotation curves observed in the gas. The differences in the line-of-sight stellar kinematics between the models and absorption line spectroscopy are minimized using a least-squares approach. The modeling constrains the disc surface density and stellar radial velocity dispersion at a fiducial radius through the free parameter $\\sqrt{M/L}$ $(\\sigma_{\\rm z}/\\sigma_{\\rm R})^{-1}$, where $\\sigma_{\\rm z}/\\sigma_{\\rm R}$ is the ratio of vertical and radial velocity dispersion and ...

International Nuclear Information System (INIS)

Electron and ion beam dynamics of the PF-1000 facility were investigated for the first time at its upper energy limit (?1 MJ) in relation to neutron emission, the pinch's plasma ('target') characteristics and some other parameters with the help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and the spatial cross correlations of different phenomena. Results of these experiments are in favour of a neutron emission model based on ion beam-plasma interaction with three important features: (1) the plasma target is hot and confined during a few 'inertial confinement times'; (2) the ions of the main part of the beam are magnetized and entrapped around the pinch plasma target for a period longer than the characteristic time of the plasma inductive storage system and (3) ion-ion collisions (both fusion collisions, due to head-on impacts and Coulomb collisions) are responsible for neutron emission. Analysis has shown that ...

CERN Document Server

NGC 1407 is the central elliptical in a nearby evolved galaxy group apparently destined to become a cluster core. We use the kinematics of globular clusters to probe the dynamics and mass profile of the group's center, out to 60 kpc (~10 R_eff) -- the most extended data set to date around an early-type galaxy. This sample consists of 172 GC velocities, most of them newly obtained using Keck/DEIMOS, with a few additional objects identified as DGTOs or as IGCs. We find weak rotation in the GC system's outer parts, with the metal-poor and metal-rich GCs misaligned. The RMS velocity profile declines rapidly to a radius of ~20 kpc, and then becomes flat or rising to ~60 kpc. There is evidence that the GC orbits have a tangential bias that is strongest for the metal-poor GCs -- possibly contradicting theoretical expectations. We construct cosmologically-motivated galaxy+dark halo dynamical models and infer a mass within 60 kpc of ~3x10^12 M_Sun, ...

CERN Document Server

The discovery of an HI cloud with peculiar properties at equatorial coordinates (J2000) ra=07h49m, dec=04d30m is presented. The HI object was detected at 21cm using the 300-m NAIC Arecibo telescope. Subsequent follow-up high-resolution observations with the NRAO Very Large Array (VLA) telescope at L-Band revealed more details about its morphology. The most intriguing aspect of the object is the clear velocity gradient of 1 km/s, which is present in the data, an indication of either rotation or expansion. The gas appears to be cold, and its morphology is somewhat elliptical with clumpy substructure. Assuming disk rotation, the dynamical mass could be determined as a function of distance.Depending on the exact nature of the velocity gradient in the HI cloud, we can reach some preliminary conclusions about the nature of the object. Expansion would imply association with a circumstellar envelope of an evolved AGB star, while in the case of ...

International Nuclear Information System (INIS)

The paper develops a new design procedure for simultaneous coordinated designing of the thyristor controlled series capacitor (TCSC) damping controller and power system stabilizer (PSS) in multi-machine power system. The coordinated design problem of PSS and TCSC damping controllers over a wide range of loading conditions is converted to an optimization problem with the time domain-based objective function that is solved by a particle swarm optimization (PSO) technique which has a strong ability to find the most optimistic results. By minimizing the proposed fitness function in which oscillatory characteristics between areas are included and thus the interactions among the TCSC controller and PSS under transient conditions in the multi-machine power system are improved. To ensure the robustness of the proposed stabilizers, the design process takes a wide range of operating conditions into account. The effectiveness of the proposed controller is ...

CERN Document Server

A risk-neutral method is always used to price and hedge contingent claims in complete market, but another method based on utility maximization or risk minimization is wildly used in more general case. One can find all kinds of special risk measure in literature. In this paper, instead of using market modified risk measure, we use a kind of risk measure induced by g_\\Gamma-solution or the minimal solution of a Constrained Backward Stochastic Differential Equation (CBSDE) directly when constraints on wealth and portfolio process comes to our consideration. Such g_\\Gamma-solution and the risk measure generated by it is well defined on appropriate space under suitable conditions. We adopt the inf-convolution of convex risk measures to solve some optimization problem. A dynamic version risk measures defined through g_\\Gamma-solution and some similar results about optimal problem can be got in our new framework and by our new ...

Energy Technology Data Exchange (ETDEWEB)

When quantum molecular dynamics (QMD) is applied to the nuclear reactions in theory of relativity region, a number of problems arise, and in order to solve them, the prescription of the extension of ordinary nonrelativistic QMD is introduced, and the analysis of proton incidence reaction by using it is shown. By introducing the interaction corresponding to Lorentz transformation, the problems were solved. QMD is the semiclassical simulation that treats the motion of nucleons represented by Gauss wave packet. The motion of wave packet center is expressed by Newton equations and two-nucleon collision. The introduction of the interaction corresponding to Lorentz transformation is explained. As the result of the introduction, through the relative distance of two particles, the interaction becomes to depend on momentum. The phase distribution function of one body corresponding to Lorentz transformation is used for calculating ...

Energy Technology Data Exchange (ETDEWEB)

There is renewed interest in the development of natural gas vehicles in response to the challenge to reduce urban air pollution and consumption of petroleum. The natural gas/diesel dual fuel engine is one way to apply natural gas to the conventional diesel engine. Dual fuel engines operating on natural gas and diesel emit less nitrogen oxides, and less carbon soot to the air compared to conventional diesel engines. The problem is that at light loads, fuel efficiency is reduced and emissions of hydrocarbons and carbon monoxide are increased. This thesis focused on control methods for emissions of hydrocarbons and carbon monoxide in the dual fuel engine at light loads. This was done by developing a reverse flow catalytic converter to complement dual fuel engine exhaust characteristics. Experimental measurements and numerical simulations of reverse flow catalytic converters were ...

Energy Technology Data Exchange (ETDEWEB)

The general responses proposed to reduce CO{sub 2} emissions to the atmosphere are conservation, improved efficiency and fuel substitution. These are valid options but other alternatives such as CO{sub 2} capture and disposal may be more attractive for specific areas. There are good reasons why the capture and disposal option fits the situation in Western Canada. The first and obvious reason is the importance of hydrocarbon energy to the regional economy. Here the economy is based on the production, utilization and sale of hydrocarbons such as coal, oil and natural gas and we intend to stay in business. Besides meeting the Canadian demand, natural gas from Alberta is used in the US as far away as Boston and Los Angeles. Canadian heavy crude oil serves much of the American Midwest and coal from the Canadian Rocky Mountains is exported to Japan. Although many may consider these hydrocarbon reserves and fossil fuel production as part of the ...

Energy Technology Data Exchange (ETDEWEB)

Tests with a 61 cm diameter fluidized-bed combustor revealed that raw cotton gin trash could be efficiently burned while satisfying Federal standards for particulate emissions. Certain chemicals within cotton gin trash zone can cause slagging or caking of ash and bed particles in the combustion zone. They can also corrode and accumulate on the heat recovery equipment. These problems are not considered insurmountable and methods of control are being studied. Raw cotton gin trash was also converted into a low Btu gas using fluidized-bed technology. Tests with a 30 cm diameter gasifier revealed that raw gin trash could be converted to a combustible gas, containing carbon monoxide and hydrogen. The heating value of the gas ranged from 3.65 to 5.29 MJ/m3 and about 50 percent of the heat value of the raw trash was converted to combustible gases. Economic analyses have shown that these techniques can be ...

Energy Technology Data Exchange (ETDEWEB)

After a lot of efforts to develop a spark-ignition type dual-fuel engine which can separately use both gas and liquid fuels, a dual-fuel engine which uses ethanol as a liquid fuel has been developed. In this paper, a 13A/LPG dual-fuel engine which uses LPG as an emergency fuel is also introduced. During the development of a dual-fuel engine using city gas (13A)/liquid fuel such 4 kinds of liquid fuel as kerosene, gasoline, ethanol and isobutanol have been examined. As a result of testing, it was proved that ethanol is preferable and a 13A/ethanol DF engine can be used as a generator of different outputs, 100KW for normal service and 70KW for emergency service, without any problems in practical use. On the other hand, a city gas (13A)/LPG dual-fuel engine requires the modification of the fuel feed system and the installation of a ignition device which can change the ignition timing by means of the fuel ...

Energy Technology Data Exchange (ETDEWEB)

Objective: Optimization and testing of a high temperature combustion chamber for burning coal gas and conventional fuels natural gas or fuel oil. Coal gas is not available in such quantity for testing a full scaled combustion chamber. Therefore the design of the combustion chamber is based of experimental results from model tests and numerical solution procedures. Working program: (1) Analytical model for burning coal gas implemented in an existing computational fluid dynamics (CFD) code. (2) Three-dimensional calculations of a full scaled combustion chamber with a CFD code for flows accompanied by combustion and chemical reaction. (3) Improvement of measuring method for determination of flame temperature and concentration. (4) Temperature and concentration profil measuring in a full scaled combustion chamber by operating with natural gas or fuel oil. Results: ...

CERN Document Server

We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities > 100 mJy at 500 um, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 um data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with Av ~4 to 5 and star formation rates of ~100 M_sun/yr. They have low gas fractions and low dynamical masses compared to 850 um selected galaxies.

Energy Technology Data Exchange (ETDEWEB)

The Computational Fluid Dynamics (CFD) Code KIVA II has been applied to model combustion pressure oscillations in the Indirect Injection Diesel Engine. These oscillations are attenuated and transmitted by the engine structure to the surroundings as noise. The computational model was used to evaluate changes in design and operating characteristics of an engine, and the effect of these on the intensity of gas pressure oscillation. The results in general corroborate the trends of published experimental measurements of combustion noise. A 40% increase in grid resolution showed minor changes in the magnitude of cylinder pressure oscillation and approximately 0.5{degree} crank angle phase advance in the oscillation cycle compared with the grid used for the results presented here. 18 refs., 18 figs.

International Nuclear Information System (INIS)

Understanding the dynamic of soil C is a key to managing soil organic matter to enhance soil fertility and ecosystem functioning and reduce trace gas emission from soils. Our objective was to determine the influence of thermically-dry sewage sludge (TSL) and municipal waste compost and the application management on soil (mixed or on soil surface) applied at sludge (TSL) and municipal waste compost and the application management on soil (mixed or on soil surface) applied at two rates of 30 t ha"-1 and 60 t ha"-1, on CO_2 fluxes, microbial biomass C (MBC) and dehydrogenase activity (DH), during an incubation study. (Author)

International Nuclear Information System (INIS)

Shut Down System - 2 (SDS - 2) of TAPP-3 and 4 works on the principle of rapid injection of gadolinium nitrate poison solution into bulk moderator in calandria using high pressure helium to shut down the reactor. This is a new system, in the context of Indian PHWRs, designed, engineered, commissioned and being operated in TAPP-3 and 4. The system design incorporates passive features such as floating polyethylene ball with ball-ball seat arrangement and locked open isolation ball valves with key interlock arrangement. This arrangement eliminates active valves downstream of poison tanks during SDS - 2 actuation. A series parallel arrangement of fast acting pilot controlled air operated valves, which keep the high pressure helium isolated from poison tanks in poised state, are the only active components. During commissioning and initial period of operation of TAPP-4, problems were encountered and were resolved by suitable modifications and the same were incorporated ...

Energy Technology Data Exchange (ETDEWEB)

The role played by calcium sulfite in the flue gas desulfurization of lime/limestone scrubbers makes it desirable to work out its thermodynamic properties. A thermogravimetric apparatus was used to study the equilibria between calcium sulfite hemihydrate and calcium sulfite anhydrite under different conditions. Efforts were made to analyze the difficulties encountered in the dynamic approach to equilibration after calcium sulfate dihydrate failed in calibration of the apparatus. Finally, the kinetics and thermodynamics for the dissociation of calcium sulfite hemihydrate were examined. The confirmation of Engel-Brewer's correlation between the electronic configuration and crystal structure in metallic systems has long been pursued in this group by studying the Lewis-acid-base interactions. Tantalum-iridium alloys of different compositions were brought into equilibrium with various steam/hydrogen mixtures in the same thermogravimetric ...

Energy Technology Data Exchange (ETDEWEB)

This thesis discusses an advanced dynamical two-dimensional cylinder symmetric model for the high temperature part of the carbothermic silicon metal process, and its computer encoding. The situation close to that which is believed to exist around one of three electrodes in full-scale industrial furnaces is modelled. This area comprises a gas filled cavity surrounding the lower tip of the electrode, the metal pool underneath and the lower parts of the materials above. The most important phenomena included are: Heterogeneous chemical reactions taking place in the high-temperature zone (above 1860 {sup o}C), Evaporation and condensation of silicon, Transport of materials by dripping, Turbulent or laminar fluid flow, DC electric arcs, Heat transport by convection, conduction and radiation. The results from the calculations, such as production rates, gas- and temperature distributions, furnace- and particle geometries, fluid ...

Energy Technology Data Exchange (ETDEWEB)

For a direct injection diesel engine to exhibit its inherent low-emission characteristics, it is essential to improve control accuracy, in particular under transient operating conditions during which emissions are more noted. A model-based control system is established for exhaust gas recirculation (EGR) and air/fuel ratio, using a diesel-engine/vehicle model established on the CAD control system. Described herein are the results of simulation for optimizing control of transient conditions, and the emission-controlling effects confirmed by the field tests. The tests for verification of the established model have confirmed that there are good agreements between the simulated and observed results in terms of air/fuel ratio changing with EGR ratio, exhaust and intake gas and pressure levels, and vehicle speed. The model will be applicable to assessment of emission characteristics under varying conditions. Simulation of the transient conditions of ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track ...

CERN Document Server

We present Sauron 2D spectrography of the central 1.5 kpc of the nearby Sey2 galaxy NGC1068, encompassing the well-known NIR inner bar. We have successively disentangled the respective contributions of the ionized gas and stars, thus deriving their 2D distribution and kinematics. The [OIII] and Hbeta emission lines exhibit very different spatial distribution and kinematics, the latter following inner spiral arms with clumps associated with star formation. Strong inwards streaming motions are observed in both the Hbeta and [OIII] kinematics. The stellar kinematics also exhibit clear signatures of a non-axisymmetric tumbling potential, with a twist in both the velocity and h3 fields. We re-examined the long-slit data of Shapiro et al (2003) using pPXF: a strong decoupling of h3 is revealed, and the central decrease in h4 hinted in the Sauron data is confirmed. These data also suggest that NGC1068 is a good candidate for a so-called sigma-drop. We confirm the possible ...

International Nuclear Information System (INIS)

A glass furnace, consisting of a combustion space and a glass melter, uses combustion heat to melt sand and cullet into liquid glass to make products. Glass quality is mainly dependent on the temperature, glass composition, and the level of impurities in a glass melter, which include solid batch/cullet particles, liquid glass, and gas bubbles. A comprehensive computational model using an Eulerian approach has been developed to simulate multiphase flows in a glass melter. It includes all the phases, divides solid particles or gas bubbles into various size groups, and treats each group as a continuum. The derived mass, momentum, and energy conservation equations of the flow are solved for local properties for each phase. The simulation considers the heating and melting of the batch (mainly from the radiative heat from combustion and from the convective heat from the molten glass), the formation and transport of bubbles, and the heating and mixing ...

Science.gov (United States)

Page 1. Dynamic Virtual LANs for Adaptive Network Security ... Dynamic Virtual LANs for adaptive network security D. Merani, A. Berni, M. Leonard ...

International Nuclear Information System (INIS)

The implementation of wind energy conversion systems in the built environment renewed the interest and the research on Vertical Axis Wind Turbines (VAWT), which in this application present several advantages over Horizontal Axis Wind Turbines (HAWT). The VAWT has an inherent unsteady aerodynamic behavior due to the variation of angle of attack with the angle of rotation, perceived velocity and consequentially Reynolds number. The phenomenon of dynamic stall is then an intrinsic effect of the operation of a Vertical Axis Wind Turbine at low tip speed ratios, having a significant impact in both loads and power. The complexity of the unsteady aerodynamics of the VAWT makes it extremely attractive to be analyzed using Computational Fluid Dynamics (CFD) models, where an approximation of the continuity and momentum equations of the Navier-Stokes equations set is solved. The complexity of the problem and the need for new design ...

Energy Technology Data Exchange (ETDEWEB)

Field and laboratory work sponsored by the Gas Research Institute (GRI) and the Department of Energy (DOE) have shown that calcium-carbonate scale formation in waters produced with natural gas and oil can be prevented by injection of phosphonate inhibitor into the formation, even if the formation is sandstone without calcite binding material. Inhibitor squeeze jobs have been carried out on DOE's geopressured-geothermal Gladys MaCall brine-gas well and GRI's co-production wells in the Hitchcock field. Following the inhibitor squeeze on Gladys McCall, the well produced over five million barrels of water at a rate of approximately 30,000 BPD without calcium-carbonate scaling. Before the inhibitor squeeze, the well could not be produced above 15,000 BPD without significant scale formation. In the GRI brine-gas co-production field tests, inhibitor squeezes have been used to successfully ...

Science.gov (United States)

Gas evolution in aluminum electrolytic capacitors constitutes one of their main drawbacks in comparison to other types of capacitors lacking a liquid electrolyte. In this respect, one of the most common causes of failure shown by liquid electrolyte capacitors is electrolyte leakage through the seal or even explosions produced by internal pressure buildup. In order to prevent these hazards, some substances, known as depolarizers, are usually added to the capacitor electrolyte with the purpose of absorbing the hydrogen evolved at the cathode (1, 2). Although the gas evolution problem in electrolytic capacitors has been known for a long time, there is a lack of literature on both direct measurements of the gas evolved and assessments of the amount of depolarizer active for the hydrogen absorption process. Aluminum electrolytic capacitors of 100..mu..F and 40V nominal voltage, miniature type (diam 8 mm, ...

Energy Technology Data Exchange (ETDEWEB)

The objective of this work is to study greenhouse gas emissions and sinks and their greenhouse impact as a function of time. The greenhouse impact is expressed in terms of global average radiative forcing, which measures the perturbation in the Earth`s radiation budget. Radiative forcing is calculated on the basis of the concentration changes of the greenhouse gases and the radiation absorption properties of the gases. It takes into account the relatively slow changes in the concentrations due to natural removal and transformation processes and also allows a comparison of the impact of various greenhouse gases and their possible control options as a function of time. In addition to the applications mentioned above, the anthropogenic greenhouse gas emission histories of Nordic countries have been estimated, and the radiative forcing caused by them has been calculated with REFUGE. The dynamic impact of aerosol emissions both ...

International Nuclear Information System (INIS)

In analysis of hydrogen in metals and alloys by SIMS, control of the hydrogen blank mainly due to residual gases is a persistent problem. Contrarity, this problem becomes less important in case of deuterium analysis. The prescribed amounts of deuterium were introduced into a pure titanium and a beta-titanium alloy (Ti- 6.6wt%Fe) by the gas reaction method. Intensities of the various secondary ions sputtered from each sample were measured by the Hitachi Ion Microanalyzer with primary ions of Ar"+. Energy distributions of the various secondary ion species were measured with the energy window of about 15eV width. The effects of oxygen gas pressure in the target chamber and the bulk deuterium concentration on the shape of energy distribution curves are discussed. For all samples, intensity of D"- ions is higher than that of D"+ ions, especially at higher energy ranges. With increasing the deuterium ...

Science.gov (United States)

Not Available

Indian Academy of Sciences (India)

problems with indian journals ...

International Nuclear Information System (INIS)

Stellar rotation and velocity-dispersion measurements are presented for the bulge components of the SBO galaxies NGC 1023, 2859, 2950, 4340, 4371, and 7743. The kinematics of nine SB bulges with data available are compared with bulges of unbarred galaxies studied by Kormendy and Illingworth. All of the SB bulges are found to rotate at least as rapidly as oblate-spheroid dynamical models which are flattened by rotation. This result confirms the conclusion of Kormendy and Illingworth that bulges rotate very rapidly. Six SB bulges found by Kormendy and Koo to be triaxial rotate even more rapidly than the oblate models. In this respect, they resemble published n-body models of bars. That is, triaxial bulges are dynamically like bars and unlike elliptical galaxies, which are also believed to be triaxial, but which rotate slowly. Measured velocity anisotropies are found to be consistent with these conclusions. Two ordinary bulges whose rotation is ...

DEFF Research Database (Denmark)

Udgivelsesdato: 2008

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

This report contains the study on the dynamic characteristics of Wolsung fuel rod and on the dynamic balancing of rotating machinery to evaluate the performance of nuclear reactor components. The study on the dynamic characteristics of Wolsung fuel rod wa...

Energy Technology Data Exchange (ETDEWEB)

The mathematical apparatus of quantum-mechanical angular momentum (re)coupling, developed originally to describe spectroscopic phenomena in atomic, molecular, optical and nuclear physics, is embedded in modern algebraic settings which emphasize the underlying combinatorial aspects. SU(2) recoupling theory, involving Wigner's 3nj symbols, as well as the related problems of their calculations, general properties, asymptotic limits for large entries, nowadays plays a prominent role also in quantum gravity and quantum computing applications. We refer to the ingredients of this theory-and of its extension to other Lie and quantum groups-by using the collective term of 'spin networks'. Recent progress is recorded about the already established connections with the mathematical theory of discrete orthogonal polynomials (the so-called Askey scheme), providing powerful tools based on asymptotic expansions, which correspond on the physical side to ...

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 ...

International Nuclear Information System (INIS)

During unit wise conditioning of unit 8, the vacuum started deteriorating inside the tube after a spark. The RGA reading was taken and it was found out that residual gas inside tube was sulphur hexafluoride. A leak was detected in second tube of unit number eight in between electrode 6 to 8. Leak was sealed with the sealant. Again leak check was done and no leak was found. The tank was closed and conditioning was started again. During the same unit number eight conditioning, leak developed again followed by a spark. So the damaged tube was replaced with a new accelerator tube. During the installation time the alignment of the machine was taken care. Again leak checking was done and the tube was baked properly. The tank was closed again and this particular unit was conditioned for about four days. The maximum voltage it has attained was 1.1 MV. (author)

British Library Electronic Table of Contents (United Kingdom)

The issue of China?s energy supply security is not only the key problem which affects China?s rapid and sustainable development in the 21st century, but also the one which international attention focuses on. Based on the notable characteristic of spatial imbalance between energy production and consumption in China, this paper takes the evolution of China?s primary energy resources development(excluding hydropower) from 1949 to 2007 as the study object, with the aim to sum up the evolutive characteristics and laws of China?s energy resources development in the past nearly 60 years. Then, based on comprehensive considerations of coal?s, oil?s and natural gas?s basic reserves, qualities, geological conditions, production status, and ecological service function of every province, this paper ad...

International Nuclear Information System (INIS)

The Fast Flux Test Facility has been in operation for approximately five years, including about one thousand days of full power operation of the Fast Test Reactor. During that time the collective dose equivalents received by operating personnel have been about two orders of magnitude lower than those typically received at commercial light water reactors. No major contamination problems have been encountered in operating and maintaining the plant, and release of radioactive gas to the environment has been minimal and well below acceptable limits. All shields have performed satisfactorily. Experience to date indicates an apparent radiological superiority of liquid metal reactor systems over current light water plants.

Energy Technology Data Exchange (ETDEWEB)

In order to apply chemical-looping combustion to a practical power plant, carbon deposition on the solid particle is one of the key problems to be overcome. Six kinds of solid particles were examined to clarify the kinetic behavior of carbon deposition. The effects of the solid composition, feed gas composition, and reaction temperature on carbon deposition were investigated by thermogravimetrical reactor on the basis of NiO/YSZ particle. From the viewpoints of both reactivity and resistance against carbon deposition, the particle of NiO mixed with YSZ (i.e., yttria-stabilized zirconia) was found to be a good candidate for chemical-looping combustion. It has been observed that carbon deposition could be completely avoided with very low concentration of water vapor. By means of a proposed model, the condition that carbon deposition would be avoided was identified. 12 refs., 8 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

Ford, Bacon and Davis Utah Inc. has reevaluated the Tuba City site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Tuba City, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 0.8 million tons of tailings at the Tuba City site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.

International Nuclear Information System (INIS)

We develop a large scale parallel viscous-elastic analysis program incorporating a mesoscopic self-consistent model developed by Laws. In the model, macroscopic elastic constants are treated as variables depending on the shape and statistical properties of pre-existing microscopic pores and change due to neutron irradiation. We apply this program to the visco-elastic analysis of nuclear graphite structures under neutron irradiation environment in High Temperature Gas-cooled Reactor (HTGR), as an example problem. Furthermore the calculated results by this parallel computational program are compared with those by one of commercial finite element analysis codes, FINAS, for validating elastic and thermal stress analysis function. (author)

Energy Technology Data Exchange (ETDEWEB)

Automatic ultrasonic testing is presented as a method for recurrent inspections of pressure gas vessels, from validation to practical testing to customised test applications. National and international regulations and standards are presented along with related implementation problems. [German] Es wird die automatisierte Ultraschallpruefung im Bereich der wiederkehrenden Pruefung von Druckgasbehaeltern, als Alternative zur herkoemmlichen, klassischen Wasserdruckpruefung, vorgestellt. Von der Validierung ueber die praktische Erprobung bis hin zur kundenspezifisch entwickelten Pruefapplikation. Es werden die Anforderungen aus nationalen und internationalen Vorschriften und Normen sowie die damit zusammenhaengenden Umsetzungsprobleme behandelt.

Energy Technology Data Exchange (ETDEWEB)

Alkanol-amine is used for removing hydrogen sulfide and carbon dioxide from the gas stream. Contaminated amine is the amine which is contaminated by hydrocarbon, organic acid or iron sulfide, etc.. In addition, in the case when an antifoaming agent is excessively added to it or when it is decomposed chemically or thermally, it is considered that it is contaminated. When an amine solution becomes contaminated, several problems concerning operation control occur which would influence the effect of the amine treatment in consequence. By using activated charcoal, it is possible to decrease the additional amount of the antifoaming agent or corrosion inhibitor. This is because activated charcoal removes the decomposed product which causes the foaming phenomenon. In order to derive economical profit sufficiently, an activated charcoal system properly designed is necessary. In this article, the CALGON CLEANAMINE SYSTEM of Calgon Co. is introduced which ...

Energy Technology Data Exchange (ETDEWEB)

The organization of the Biofuels Excellence Network, inside PROMINP - the Program of Mobilization of the National Industry of Oil and Natural Gas, has the objective of improving the actions of technical innovation and management in the chain of Oil, Gas Natural and Biofuels, through the optimized use of physical, financial, technological resources, of information and staff, with maximum qualification in areas of the human knowledge, whose purpose is to make decisions on specific problems of improvement of processes and/or products, besides promoting actions for the development and reinforcement of the markets of ethanol and biodiesel. The organization of the Biofuels Excellence Network became necessary, in order to enable Brazil to reach vanguard standards in biofuels (ethanol and biodiesel) in a sustainable, competitive and environmentally responsible way. Among the main reasons for the creation of the Biofuels Excellence ...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

The nuclear power industry has experienced four carbon based adsorbent fires in its history, one was of the Monticello Standby Gas Treatment System and other three were in various off-gas delay beds. Although, some of the latter may not be classified as a full fledged fires. There were a number of experiments performed relating to igniting carbon beds and experiments relating to attempts at extinguishing set fires reported in the literature. Review of these experiments indicates that fire resulting from decay heat of adsorbed radioactive iodine is not justified even under the somewhat unrealistic source terms still in effect. At the same time the non-nuclear chemical industry application of carbon base adsorbents for solvent recovery has resulted in numerous fires and significant property losses. Fire control systems installed in nuclear air cleaning systems in the US consists of water deluge. Accidental initiation of these systems has occurred ...

Energy Technology Data Exchange (ETDEWEB)

For developing coal liquefaction processes, it is an important problem to improve the light oil yield with increased oil yield. It was previously reported that distillate mainly containing lighter fraction can be produced with high oil yield by reducing the iron/sulfur catalyst addition in slurry, by recycling gas in the process operation, by utilizing these effects, and by using heavy oil as recycling solvent. In this study, the maximum distillate yield of Victorian brown coal was investigated through continuous liquefaction using a bench scale unit. In addition, operation conditions for obtaining sufficient oil yield were investigated under the reduced catalyst addition into one-third. Consequently, it was confirmed that the maximum content of lighter fraction in distillate product was obtained with reduced catalyst addition by using heavy oil as recycling solvent, by adopting new catalyst, and by utilizing effects of CLB recycling and ...

Energy Technology Data Exchange (ETDEWEB)

A process model is presented and used for identifying options for controlling the cupola furnace process and for investigating natural gas substitutes. Fuel substitution will affect temperature curves (i.e. tapping temperatures and melting capacity), outlet temperatures and gas mass flow out of the preheating zone. The contribution presents several process variations to overcome these problems and compares them with the natural gas process. [German] Mit dem Prozessmodell werden zunaechst Moeglichkeiten der Steuerung von Abstichtemperatur und Schmelzleistung, insbesondere unter Beruecksichtigung der Schrottqualitaet (spezifische Oberflaeche a{sub G}), untersucht. Es wird gezeigt, dass das Prozessmodell die Ergebnisse aus der Praxis wiedergibt. Daran anschliessend wird mit dem Prozessmodell die Substitution von Erdgas durch minderwertige Gase untersucht (Brennstoffsubstitution, Ressourcenschonung). Durch ...

Energy Technology Data Exchange (ETDEWEB)

Coal may be used to generate electrical energy by any of several processes, most of which involve combustion or gasification. Combustion in a coal-fired boiler and power generation using a steam- cycle is the conventional conversion method; however, total energy conversion efficiencies for this type of process are only slightly over 30{percent}. Integration of a gas-cycle in the process (combined cycle) may increase the total conversion efficiency to 40{percent}. Conversion processes based on gasification offer efficiencies above 50{percent}. H{sub 2}S is the predominant gaseous contaminant in raw coal gas. Problems arise due to the corrosive nature of H{sub 2}S on metal components contained in these cycles. Because of this, H{sub 2}S concentrations must be reduced to low levels corresponding to certain power applications. An advanced process for the separation of hydrogen sulfide (H{sub 2}S) from coal gasification product ...

International Nuclear Information System (INIS)

Various kinds of decontaminations are carried out in atomic power plant. Here current decontamination technologies such as chemical decontamination with chemical solution or blast decontamination have a problem of reduction of secondary radioactive waste generated in the decontamination process. On the other hand, a low pressure arc plasma can remove metal oxide film on the metal substrate without heavy damage on the metal substrate when the object to be treated was set as a cathode. Dry surface decontamination technology with using low-pressure arc plasma can decrease secondary radioactive waste because low-pressure arc plasma does not need any chemical solution. In addition, the time required for treatment can be shorter, so it is possible for the low-pressure arc plasma decontamination technology to interpolate the current decontamination technologies such as spot decontamination technology etc. Therefore we have been investigating the dependence of removal of ...

CERN Document Server

Distributed denial of service attacks are often considered a security problem. While this may be the way to view the problem with today's Internet, new network architectures attempting to address the issue should view it as a scalability problem. In addition, they need to address the problem based on a rigorous foundation.

Energy Technology Data Exchange (ETDEWEB)

A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solid phases. An evaporation submodel treats not only droplet ...

Energy Technology Data Exchange (ETDEWEB)

The invention relates to a method for purifying a gas mixture containing at least one undesirable gas compound utilizing certain sulfonamide or sulfamide solvents.

Energy Technology Data Exchange (ETDEWEB)

Co-combustion tests for recycled fuels and peat were made at a 15 kW fluidized bed reactor at VTT Energy in Jyvaeskylae. Peat was used as reference fuel. 25 tests in total were performed during 1994 - 1996. A part of the peat energy was substituted by coal in five tests, in order to change the sulphur/chlorine ratio of the fuel mixture. Fuel mixtures (25% recycled fuel and 75% peat, at energy ratio) were pelletized in order to get homogeneous fuel mixtures. The tests in the year 1994 were air staging experiments (with and without tertiary air). All test were performed with air staging in the years 1995 and 1996. The aim of the research was to determine whether the co-combustion of waste materials will cause additional emission problems, as compared to combustible emissions from conventional air-staged fluidized bed combustion. Further, the aim was to study which large-volume components can be burned safely. One aim was to study the influence of fuel properties and ...

CERN Document Server

Amperostatic coulometry was applied for the thickness measurement of Sn-Ag hot dip coatings, which comprise an extended Sn-Cu interdiffusion layer. Complementary measurements, notably weight loss, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray fluorescence (XRF), and dynamic secondary ion mass spectroscopy were performed in order to obtain a better interpretation of the coulometry results. Based on the experimental results presented in this article, the three potential changes observed during coulometry measurements are ascribed to (i) the entire dissolution of pure Sn, (ii) the formation of a CuCl salt layer, and (iii) the surface passivation. The measurement of the pure Sn mass is well reproducible despite strong coating thickness variations detected by XRF. Several experimental problems, in particular, a coating undercutting, hamper the determination of the Sn mass in the intermetallic Sn-Cu layer. (19 refs).

Energy Technology Data Exchange (ETDEWEB)

We revisited the quantum Zeno paradox, which claims that a generic quantum system prepared in a state which is not an eigenstate of the Hamiltonian operator and is continuously observed never decays. Since any perfectly isolated quantum system always interact with a vacuum field, we analyze the possibility of using this fact to solve the above mentioned conceptual problem. Therefore we discuss a two-level system or qubit-Bose field interaction Hamiltonians. We consider the quantum dynamics of this two-level system, prepared in the excited state interacting with a Bose field prepared in the Poincare invariant vacuum state. Using a first-order approximation in time-dependent perturbation theory, we evaluate the probability of spontaneous decay of the two-level system driven by the vacuum field. This probability is evaluated for a finite time interval. Using the standard argument to obtain the quantum Zeno paradox, we consider N measurements where ...

Energy Technology Data Exchange (ETDEWEB)

We consider spatially homogeneous (but generally non-isotropic) cosmologies in the recently proposed Horava-Lifshitz gravity and compare them to those of general relativity using Hamiltonian methods. In all cases, the problem is described by an effective point particle moving in a potential well with exponentially steep walls. Focusing on the closed-space cosmological model (Bianchi type IX), the mixmaster dynamics is now completely dominated by the quadratic Cotton tensor potential term for a very small volume of the universe. Unlike general relativity, where the evolution toward the initial singularity always exhibits chaotic behavior with alternating Kasner epochs, the anisotropic universe in Horava-Lifshitz gravity (with parameter lambda > 1/3) is described by a particle moving in a frozen potential well with fixed (but arbitrary) energy E. Alternating Kasner epochs still provide a good description of the early universe for very ...

Energy Technology Data Exchange (ETDEWEB)

The deregulation of the power industry having been implemented at unparalleled pace in Germany, the marketers and utility managers have been faced with the challenge of coping within relatively short time with the whole range of problems involved in restructurisation in the emerging competitive and very dynamic market. The article summarizes the activities for reorientation and positioning in the market, laying the foundation for success in the future. The communication and IT infrastructure is a major aspect to be considered. The authors explain how the German power industry may profit from international experience and results, so as to gain time in pulling up with competitors in the international marketplace. (orig./CB) [German] Die Liberalisierung der deutschen Stromwirtschaft kann im internationalen Vergleich als einzigartig sowohl hinsichtlich ihrer Breite als auch ihrer Geschwindigkeit - volle Marktoeffnung fuer alle Kunden auf einen ...

Science.gov (United States)

This dissertation reports on the application of numerical optimization techniques as applied to fuel cell simulation and design. Due to the "multi-physics" inherent in a fuel cell, which results in a highly coupled and non-linear behavior, an experimental program to analyze and improve the performance of fuel cells is extremely difficult. This program applies new optimization techniques with computational methods from the field of aerospace engineering to the fuel cell design problem. After an overview of fuel cell history, importance, and classification, a mathematical model of solid oxide fuel cells (SOFC) is presented. The governing equations are discretized and solved with computational fluid dynamics (CFD) techniques including unstructured meshes, non-linear solution methods, numerical derivatives with complex variables, and sensitivity analysis with adjoint methods. Following the validation of the fuel cell model in 2-D and 3-D, the ...

Energy Technology Data Exchange (ETDEWEB)

This thesis consists of five chapters, each of which is a self-contained unit. The first chapter overviews methods for electronic-structure calculations. Chapter 2 introduces a new method to generate a rapidly converging configuration expansion. The approach iteratively combines (1) a least-squares fitting of a configuration expansion to a many-body wave function with (2) a transfer-matrix method for projecting out the ground state. Results are shown to be equivalent to multiconfiguration Hartree-Fock. Results from test calculations are given for a simple finite difference model of the helium atom. In Chapter 3 the use of the finite-element method in electronic structure calculations is discussed. Chapters 4 and 5 discuss developments in Monte Carlo methods based on Hubbard-Stratonovich transformations. Chapter 4 introduces a canonical ensemble formulation of the method, which is more appropriate than the usual grand canonical formulation for electronic structure. Chapter 5 considers ...

International Nuclear Information System (INIS)

The liberalization of the electricity sector requires utilities to develop sound operation strategies for their power plants. In this paper, attention is focused on the problem of optimizing the management of the thermal power plants belonging to a strategic producer that competes with other strategic companies and a set of smaller non-strategic ones in the day-ahead market. The market model suggested here determines an equilibrium condition over the selected period of analysis, in which no producer can increase profits by changing its supply offers given all rivals' bids. Power plants technical and operating constraints are considered. An iterative procedure, based on the dynamic programming, is used to find the optimum production plans of each producer. Some combinations of power plants and number of producers are analyzed, to simulate for instance the decommissioning of old expensive power plants, the installation of new more efficient ...