British Library Electronic Table of Contents (United Kingdom)

The mechanism of abrupt increase of the giant magneto impedance (GMI) ratio in the ion irradiated Co-based amorphous ribbon has been investigated. The grazing incident X-ray diffraction and transmission electron microscope were used to characterize the samples before and after ion irradiation. The GMI-ratio considerably increased in the ion irradiated samples and the GMI response showed strong dependence on the driving frequencies. The Barkhausen noise (BN) signals are increased for the Ar ion irradiated sample with dose of 1x10^1^7 ion/cm^2. The results are interpreted in terms of GMI variation associated with domain wall dynamics.

Science.gov (United States)

The Bingham plastic constitutive model has been widely used to predict the post-yield behavior of electro- and magneto- rheological fluids (ER and MR fluids). However, if these fluids experience shear thinning or shear thickening, the Bingham plastic model may not be an accurate predictor of behavior, since the post-yield plastic viscosity is assumed to be constant. In a recent study, it was theoretically and experimentally demonstrated that the Herschel-Bulkley fluid model can be successfully employed when evaluating non- Newtonian post-yield behavior of ER and MR fluids. In this paper, the Herschel-Bulkley model is employed to include a detailed analysis of ER and MR fluid dynamics through pipes and parallel plates. Simplified explicit expressions for the exact formulation are also developed. It is shown that the proposed simplified model of the Herschel-Bulkley steady flow equations for pipes and parallel plates can be used as an accurate ...

Science.gov (United States)

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KoreaScience (Korea)

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Norwegian Open Research Archives (NORA)

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International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

British Library Electronic Table of Contents (United Kingdom)

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 beg...

International Nuclear Information System (INIS)

Full text.This paper describes a software tool for generation expansion planning based on dynamic programming, probabilistic production simulation, and environmental assessment. The aim is to determine the units needed to expand a given system in order to minimize either the cost or the environmental impact or some weighed function of the two. The problem of generation expansion planning is solved in stages using Tunnel Dynamic Programming (TDP) with Heuristic rules to limit the number of options analyzed. The production costing methodology is based on combining a probabilistic generation model known as the capacity outage table (COT) with the load duration curve (LDC) of the system to deduce a risk model from which the expected energy not supplied (EENS) is estimated. The generation model is built recursively using an efficient numerical convolution procedure and is combined at each step with the LDC to calculate the expected energy produced ...

CERN Document Server

Calculations relating to two experiments that demonstrate coherent control of preformed rubidium-85 molecules in a magneto-optical trap using ultrafast laser pulses are presented. In the first experiment, it is shown that pre-associated molecules in an incoherent mixture of states can be made to oscillate coherently using a single ultrafast pulse. A novel mechanism that can transfer molecular population to more deeply bound vibrational levels is used in the second. Optimal parameters of the control pulse are presented for the application of the mechanism to molecules in a magneto-optical trap. The calculations make use of an experimental determination of the initial state of molecules photoassociated by the trapping lasers in the magneto-optical trap and use shaped pulses consistent with a standard ultrafast laser system.

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 life prototypes. The first mutating, ...

British Library Electronic Table of Contents (United Kingdom)

We have explored vibrations of a single-degree of freedom oscillator with a magneto-rheological damper subjected to kinematic excitations in a high frequency limit. Using fast and slow scales decoupling procedure we derived an effective damping coefficient in the limit of high frequency excitation. Damping characteristics, as functions of velocity, change considerably especially by terminating the singular non-smoothness points. This effect was more transparent for a larger control parameter which was defined as the product of the excitation amplitude and its frequency.

Science.gov (United States)

This paper focuses on a theoretical model that predicts the temperature increase of Magneto-rheological (MR) fluid dampers experiencing a sinusoidal input motion. A theoretical model is developed to estimate the temperature rise based on the non-linear behavior of the MR fluid damper. This model is solved numerically, and the numerical solution is compared with a known linear solution and experimental result in order to validate the accuracy of the model. Also, a non-dimensional form of the governing equations are developed to examine the key parameters. The non-dimensional terms show the effect of external and internal parameters on the trends of heat dissipation as well as heat generation within the MR fluid damper.

Energy Technology Data Exchange (ETDEWEB)

The half-metallic Heusler alloy Ni{sub 2}MnIn is of high interest for use in spin electronics since at the Ni{sub 2}MnIn/InAs interface a spin polarization of 100% is predicted. We prepare high-quality thin films of 20-60nm thickness by co-evaporation and DC magnetron sputtering. Point-contact Andreev reflection spectroscopy yields a spin polarization of up to 54%. By spectral generalized magneto-optical ellipsometry, the dielectric and magneto-optical properties are determined and ferromagnetic behavior below the Curie temperature T{sub C}=318K is proved.

Energy Technology Data Exchange (ETDEWEB)

BC Hydro recently conducted a demonstration test of a bearing condition monitor. The test, at the 529-MW Kootenay Canal project, proved the ability of the monitor to detect machine condition faults. The capability to detect changing conditions during normal operation of hydroelectric machines gives hydro plant owners the opportunity to anticipate needed maintenance and ultimately to reduce the number of equipment failures. BC Hydro intends to install bearing condition monitors, as well as windings monitors, brushgear monitors, environmental monitors, and other selected systems in as many as 46 of its hydro generators. BC Hydro analyzed forced outages between 1985 and 1989 in its hydro system to identify which parts of a generating unit resulted in the highest number of hours of outage. From there, the utility has formulated a concept for a machine condition ...

Energy Technology Data Exchange (ETDEWEB)

An overview of BC Hydro`s review of its overhead transmission system to withstand earthquakes and its program of seismic upgrading, including the upgrading of tower pile foundations in liquefiable soils, was presented. BC Hydro`s system, geologic environment, seismic design criteria, investigations and analysis, treatment and alternatives and a case history of a seismic upgrade of a tall river crossing tower at the Pitt River in the Lower Mainland of B.C. were summarized. It was concluded that the inherent strength of towers, conductors, fittings and insulators was sufficient to withstand earthquakes. The towers most susceptible to slope and soil failure due to seismic activity were tall river crossing towers. It was suggested that soils investigations, seismicity, ground response, liquefaction and stability analyses be carried out at each site. The results of these tests would help to establish system seismic design criteria at each location. ...

Energy Technology Data Exchange (ETDEWEB)

Japan's first water power station to provide public power was the Keage plant (maximum output 160 kW) which began operation in 1891. The installed capacity of pure hydro plants reached 20 481 MW in March 1991; pumped-storage powerplants account for 17 004 MW, making a total of 37 483 MW. Pumped-storage thus represents 45 per cent of total hydro capacity. Pure hydro plants under construction at the end of March 1990 totalled 75, representing 968 MW of capacity. There were also seven pumped-storage plants under construction (each more than 300 MW). The latest survey to establish the hydro potential of Japan indicated the gross theoretical hydro potential to be 717 600 GWh/year and the exploitable potential to be 130 524 GWh/year. Of this exploitable potential, 60 per cent is in operation and 3 per cent is under construction. The exploitable potential represents 4551 pure ...

British Library Electronic Table of Contents (United Kingdom)

In vibration control field, magneto-rheological (MR) fluid dampers are semi-active control devices that have recently begun to receive more attention. This paper presents a nonlinear black-box model (BBM) and an inverse black-box model (IBBM) for the identification of a MR fluid damper and their application to design a novel force-sensorless control method for any damping system using that damper. The nonlinear model named 'black-box' is a simple direct modeling method which was designed based on fuzzy-neural technique. Characteristics of the damper in study are directly estimated through a fuzzy mapping system. In order to improve the model accuracy, neural network technique including back-propagation and gradient descent method were used to train the fuzzy parameters to minimize the mode...

British Library Electronic Table of Contents (United Kingdom)

In vibration control field, magneto-rheological (MR) fluid dampers are semi-active control devices that have recently begun to receive more attention. This paper presents a black-box model (BBM) for identification of a MR fluid damper and its application to vibrating control systems using that damper with self-sensing behavior. A model named ''black-box'' is a simple direct modeling method which is designed for a typical MR fluid damper using the self-tuning fuzzy technique. The characteristics of the researched damper are directly estimated through a fuzzy mapping system. In order to improve the accuracy of the proposed model, the back propagation algorithm and gradient descent method were used to train the fuzzy parameters to minimize the model error function. Consequently, the BBM with ...

International Nuclear Information System (INIS)

The purpose of work is systematical studying of benzo (B) of thiophene-1,1-dioxides and their 2,3-di-hydro derivatives behaviour in the reactions of electrophflic, radical, nucleophilic nitration, reduction of nitro group, embodiment of synthesis of N-amino derivatives, investigation of sulfur containing hetero-cyclic compounds, including of residues of some steroids

Science.gov (United States)

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Energy Technology Data Exchange (ETDEWEB)

No information on steam/water two-phase flow behavior in large diameter pipes (10 inch or larger) at elevated pressures is available in the open literature. However, there are many applications, in the nuclear, chemical and petroleum industries among others where two-phase flows in large diameter pipes at elevated pressures and temperatures are encountered routinely or under accident scenarios. Experimental data on steam-water two-phase flow in a large diameter (20 inch, 50.08 cm I.D.) vertical pipe at elevated pressures and temperatures (2.8 MPa/230 C--6.4 MPa/280 C) have been obtained. Void fraction, two-phase mass flux, phase and velocity distributions as well as pressure drop along the test pipe have been measured using the Ontario Hydro Technologies (OHT) Pump Test Loop. The void fraction distributions were found to be axially symmetric and nearly flat over a wide range of two-phase flow conditions. The two-phase flow regime could be inferred from the ...

Energy Technology Data Exchange (ETDEWEB)

Our latest survey of hydro resources demonstrates the significant role that hydroelectric power continues to play in world energy supply. Our statistics have been revised, updated and expanded this year (1992) on the basis of a detailed questionnaire sent to power authorities around the world. For cases where data could not be obtained in this way we have collaborated with the World Energy Council, the United Nations and OLADE. The four tables this year give data by country and geographical region for the following: 1. Hydropower potential: a detailed breakdown of gross theoretical, technically feasible and economically feasible hydro potential, as well as the dates when the figures were last evaluated. 2. Hydro capacity in operation, under construction and planned (pure hydro only excluding contributions derived from pumped storage). 3. Hydropower ownership: data on public versus independent producers. ...

Energy Technology Data Exchange (ETDEWEB)

Phenomena associated with induced currents and voltages on high voltage transmission lines were discussed. Basic principles were reviewed. Action taken by Hydro-Quebec to assess the importance of associated problems on its grid was described. Hydro-Quebec`s findings and recommendations were compared with those of the International Standard, IEC 1129. It was concluded that for most cases, induced currents and voltages were higher than those listed under Class A recommendations of IEC 1129 as rated switching capabilities for ground switches assigned to this duty. For worst case scenarios, it was also found that, values of induced currents and voltages were lower than those of Class B recommendations. Hydro-Quebec and GEC Alsthom T and D collaborated to design and type test a full range of low cost and efficient ground interrupter switches tailored to Hydro-Quebec`s needs. A list of general application ...

International Nuclear Information System (INIS)

The structural changes attendant on intermartensitic transformation in a Ni-Mg-Ga shape memory alloy are considered using magneto-optical visualization with the help of ferrite-garnet monocrystalline films. It is established that on the intermartensitic transformation the complete reorganization of martensite macrostructure fails. Martensite crystals resulted from the basic transformation change somewhat their sizes on intermartensitic transition. The existence of large-scale labyrinth magnetic domain structure is revealed

Energy Technology Data Exchange (ETDEWEB)

The properties of Mn-doped GaAs layers grown by laser deposition were investigated with measurements of Hall effect and magneto-optical Kerr effect (MOKE). The electrical and magnetic parameters of the layers were defined by growth temperature and quantity of sputtered Mn. It was shown that room-temperature ferromagnetism is revealed by MOKE and, after ruby laser 25 ns pulse annealing, by Hall effect measurements.

International Nuclear Information System (INIS)

Tata Electric Companies (TEC) are engaged in the generation of hydro and thermal energy. TEC, to minimise backing down of its thermal units in off peak hours and also to at least partially meet the growing deficit in the supply during peak hours is moving to install pumped storage plants (PSPs) utilising off-peak surplus energy for pumping the water from lower pond to the upper pond for subsequent utilisation for power generation during peak hours. In view of some of the infra structural facilities such as storage ponds, water conductor system, transmission lines, etc. being already available, at the existing hydro power stations owned by TEC, the pumped storage units are being proposed within the environs of existing hydro stations, i.e. a 150 MW pumped storage unit at Bhira and a 90 MW pumped storage unit at Bhivpuri. The projects are described and cost estimates is given. (author). 2 figs.

International Nuclear Information System (INIS)

Manitoba Hydro's Ice Storm Management Program to reduce ice damage to overhead power lines in the voltage range of 8 kV to 115 kV is described. Overhead power lines are de-iced either by AC ice melting, which involves placing a three-phase short at a calculated point, or ice rolling, which is a process of mechanically stripping ice from conductors. Direct current heating and underground distribution systems are also accepted prevention measures. Advantages and disadvantages of each of these methods of de-icing are reviewed. Material for this paper has been extracted from a workshop manual prepared for the 1993 and 1998 Ice Storm Management workshops organized by Manitoba Hydro through the Canadian Electrical Association. 1 ref.

Energy Technology Data Exchange (ETDEWEB)

BC Hydro`s approach to improve the performance of its underground transmission lines by employing new computer technology with fibre optic cables was described. Known as Distributed Temperature Sensing (DTS), the technology is expected to increase the capacity of the most heavily-loaded sections of its seven kilometer underground 230 kV transmission system in the Greater Vancouver area. Although it is also a concern in overhead wires, heating is particularly problematic in underground cable systems. DTS uses opto-electronic equipment to launch a laser light down conventional communications-grade fibre optic cables, installed in the same duct as the cables, or in a spare duct next to them. By using high speed measurements and computer processing, it is possible to determine the temperature all along the fibre with very high accuracy, and to locate any point along the length of the cable line to within two meters over distances up to 10 kilometers. Knowing the ...

British Library Electronic Table of Contents (United Kingdom)

A HydroSele S seal from James Walker has provided more than two years maintenance-free service at the large Entracque pumped-storage hydroelectric scheme in Italy.

UK PubMed Central (United Kingdom)

Introduction:Single-stream hydro-jet dissection is increasingly used in various laparoscopic procedures, but its use requires special equipment. We describe a simple method for using...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The technical potentials of electric power generation from hydro power in Germany, the current harnessing of hydro power, its costs, and certain characteristic quantities reflecting its effects on the environment are described. These diverse characteristic quantities are compared with those of other renewable and fossil energy sources used to generate electricity. On this basis, opportunities for extending the use of hydro power in Germany and its limits are discussed. (orig.) [Deutsch] Das Ziel der folgenden Ausfuehrungen ist, die technischen Potentiale und deren derzeitige Nutzung, die Kosten und bestimmte die Umwelteffekte beschreibende Kenngroessen einer Stromerzeugung aus Wasserkraft in Deutschland darzustellen. Diese unterschiedlichen Kenngroessen werden anschliessend mit denen anderer regenerativer Energien und fossiler Energietraeger zur Stromerzeugung verglichen. Ausgehend davon werden die Moeglichkeiten und ...

Energy Technology Data Exchange (ETDEWEB)

This report illustrates how, thanks to the development of a new algorithm for the probabilistic evaluation in a given period (e.g. one week) of the operating costs and risk indices (reliability) of a generation system with energy-constrained units, it has been possible to significantly improve the WAT program, used for many years by ENEL for generation expansion planning studies. In particular, it describes how the annual simulation of the system operation is accomplished, so as to calculate the mean expected values of the yearly operating costs (fuel) and the risk indices, at the same time optimizing the use of hydro resources and pumped-storage plants. (author).

Energy Technology Data Exchange (ETDEWEB)

A fast production scheduling algorithm suitable for generation expansion studies is described in this paper. It can handle several independent rivers, thermal plants, pumped storage plants, import, export, and internal non-firm markets. Inflows and load are deterministic and a one-reservoir limit is imposed on each river. The scheduling problem is formulated as a generalized network problem which is efficiently solved by an adaption of the simplex method. The algorithm is part of a program developed by Hydro-Quebec to conduct preliminary evaluations of alternative expansion plans. The program and the scheduling algorithm are presented.

Energy Technology Data Exchange (ETDEWEB)

The defects localization in power cables follows several steps: identification, pre-localization and precise localization. Pre-localization methods, other than echo-metry, are presented first: bridge methods, particular case of low voltage networks, future perspectives. Then, the precise localization methods are described: magneto-acoustic method, audible frequencies method. The particular case of underwater and high-voltage cables is considered too (oil and gas leaks detection). (J.S.)

Science.gov (United States)

New industrial Non Destructive Testing requires the development of new probes: technologies such as high spatial resolution probes for small breaking flaws detection or flexible probes for complex curved surfaces inspection. The CEA/LIST has designed and integrated 2 probes to answer industrial's constraints. The first one is based on Giant Magneto-Resistance and is able to detect 50 ?m3 flaws. The second one is based on micro-coils etched on kapton and its flexibility is adapted to curved surfaces inspection. Both are multi-elements probes, allowing fast inspection. This paper presents those new probes, their design and their performances.

CERN Document Server

Individual laser cooled atoms are delivered on demand from a single atom magneto-optic trap to a high-finesse optical cavity using an atom conveyor. Strong coupling of the atom with the cavity field allows simultaneous cooling and detection of individual atoms for time scales exceeding 15 s. The single atom scatter rate is studied as a function of probe-cavity detuning and probe Rabi frequency, and the experimental results are in good agreement with theoretical predictions. We demonstrate the ability to manipulate the position of a single atom relative to the cavity mode with excellent control and reproducibility.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The application of fossil fuels and the simultaneous dependency on fuel imports can only be decreased through consequent utilisation of efficient hydro power which is the most efficient way to avoid CO{sub 2} emissions. Only some decades ago hydro power plants were buildings erected according to met technical demands. In the 1990s rethinking started and the new designs took into account ecology and architecture. Maintenance and/or improvement of ecological efficiency play a decisive role. Experts of ecology and environmental protection of different faculties are involved right from the beginning when planning starts in order to obtain a maximum of nature compatibility and to develop efficient ecological accompanying and compensating measures. Landscape is being recultivated sustainably during construction activities in order to offer biota optimum conditions of living. Devices supporting fish migration are state of the art and designed in such ...

British Library Electronic Table of Contents (United Kingdom)

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. In this research, scenarios for 2020 EVs penetration and charging profiles are studied integrated with different hypotheses for electricity production mix. The impacts in load profiles, spot electricity prices and emissions are obtained for the Portuguese case study. Simulations for year 2020, in a scenario of low hydro production and high prices, resulted in energy costs for EVs recharge of 20cents/kWh, with 2 million EVs charging mainly at evening peak hours. On the other hand, in an off-peak recharge, a high hydro production and low wholesale prices'...

Energy Technology Data Exchange (ETDEWEB)

Results are presented of an extensive investigation of the characteristics of over two hundred low-head turbines manufactured all over the world that have been installed or are due to be installed in hydropower plants between 1953 and 1984. The research focused mainly on bulb turbines, with horizontal shaft arrangement and tubular turbines with their shafts either horizontal or inclined at an angle to the horizontal. The characteristics of the above mentioned type of turbines are presented in the form of statistical diagrams and regression equations suitable for preliminary design and feasibility studies of low-head hydro projects. Nomographs have been developed for displaying the relationships between the various turbine characteristics and comparing the important dimensions and parameters of turbines which have found common application in the hydropower technology. New simplified parametric ratio for selection of turbines have been developed that should expedite ...

British Library Electronic Table of Contents (United Kingdom)

The study has analysed the effects of various factors on hydroelectric power generation potential to include climate change/variability, water demand, and installation of proposed hydroelectric power schemes in the Zambezi River Basin. An assessment of historical (1970?2000) power potential in relation to climate change/variability at existing hydro electric power schemes(Cahora Bassa, Kariba, Kafue Gorge and Itezhi-Tezhi) in the Zambezi River Basin was conducted. The correlation of hydroelectric power potential with climate change/variability aimed at observing the link and extent of influence of the latter on the former was investigated. In order to predict the future outlook of hydro electric power potential, General Circulation Models (GCM) were used to generate projected precipitation...

International Nuclear Information System (INIS)

Recently, it has become clear that the chemical circumstances under which long-term geological evolution occurs must be properly evaluated in order to develop effective remediation programs for contaminated soil, landfills, radioactive waste repositories, and carbon dioxide capture and storage. The issue of acidic leakage from excavated rock stuck was assessed using a hydro-geochemical simulator, TOUGHREACT. We concluded that in order to properly investigate the phenomenon of acidic leakage from excavated pyrite-containing rock stuck, it is important to obtain accurate information about the following factors: intensity of rainfall, unsaturated flow properties of the excavated rock stuck, specific surfaces for oxidation reaction of pyrite, the species and the quantity of other minerals contained in the rock, and secondary minerals produced. (author)

Science.gov (United States)

This paper presents a semi-active vibration control of a scaled two-span bridge structure. Magneto-rheological fluid dampers are utilized as the semi-active energy absorbing deices and a bridge vibration control system is developed. Closed-loop control system based on fuzzy logic is used to suppress the bridge deck motion under random excitations. The sufficient condition for the closed-loop stability of the fuzzy control system is derived from the variable structure system theory. It is demonstrated that this stable fuzzy control system can significantly reduce the relative deck displacement using about 55 percent less power compared to passive-on state, while the absolute deck acceleration is relatively unaffected.

CERN Document Server

The laser cooling and trapping of ultracold neutral dysprosium has been recently demonstrated using the broad, open 421-nm cycling transition. Narrow-line magneto-optical trapping of Dy on longer wavelength transitions would enable the preparation of ultracold Dy samples suitable for loading optical dipole traps and subsequent evaporative cooling. We have identified the closed 741-nm cycling transition as a candidate for the narrow-line cooling of Dy. We present experimental data on the isotope shifts, the hyperfine constants A and B, and the decay rate of the 741-nm transition. In addition, we report a measurement of the 421-nm transition's linewidth, which agrees with previous measurements. We summarize the laser cooling characteristics of these transitions as well as other narrow cycling transitions that may prove useful for cooling Dy.

British Library Electronic Table of Contents (United Kingdom)

The effects of thermal radiation and viscous dissipation on magneto-hydrodynamic (MHD) unsteady free-convection flow over a semi-infinite vertical porous plate are analysed. The fluid considered is non-gray (absorption coefficient dependent on wave length). The Network Simulation Method is used to solve the boundary-layer equations based on the finite-difference formulation; only discretization of the spatial co-ordinates is necessary, while time remains as a real continuous variable. This method provides a solution for both transient and steady-state problems at the same time, and programming does not require manipulation of the sophisticated mathematical software that is inherent in other numerical methods. The velocity, temperature, local skin-friction and local Nusselt number are studi...

British Library Electronic Table of Contents (United Kingdom)

In this study structural and magnetic character of the expanded austenite phase (gN) layer formed on a medical grade CoCrMo alloy by a low-pressure Radio-Frequency plasma nitriding process was investigated. The formation of the expanded austenite phase is facilitated at a substrate temperature near 400^oC for 1, 2, 4, 6 and 20h under a gas mixture of 60% N2-40% H2. The magnetic state of the gN layers was determined by a surface sensitive technique, magneto-optic Kerr effect (MOKE), and with a scanning probe microscope in magnetic force mode (MFM). Strong evidence for the ferromagnetic nature of the gN-(Co,Cr,Mo) phase is provided by the observation of stripe domain structures and the hysteresis loops. The ferromagnetic state for the gN phase observed here is mainly linked to large lattice ...

Energy Technology Data Exchange (ETDEWEB)

Success in improving hydropower project efficiency has opened more global markets for variable-speed generator technology. Manufacturers continue to test the markets as the technology evolves. The potential of variable-speed application becomes evident considering that more than 150 pumped storage plants, with a combined capacity exceeding 100,000 MW, are in operation globally.

Wastenet

...understanding sweden publication publication market publications publications inco publications library public-private partnerships publishing publishing platform pufafeed puglia pulmonary diseases pulp puma pumped hydro storage pumped storage plants purity purpose purpose-grown energy crops purposes pv pv added value pv cells pv crystalline cells pv organic and polymer cells pv research pv ...

International Nuclear Information System (INIS)

To the crushed ore leaching is applied. The resulting solid-liquid mixture is fed to a hydro-cyclon grading facility; here the superfine grain is separated before the concentrated mixture can be filtered or centrifuged. The grading is done in several steps. From the liquid, ultimately ridded of the solid, uranium compounds are precipitated and the yellow cake is obtained. (DG).

Energy Technology Data Exchange (ETDEWEB)

The energy challenges of the next 30 years appear daunting and, in certain cases, in conflict with one another. Their complexity is such that one solution alone cannot provide a full answer. It is nevertheless equally clear that hydro-electricity, being renewable, proven, highly efficient, storable and with still very significant resource potential, possesses a unique combination of attributes which will aid decision-makers to plan and execute energy development with confidence.

DEFF Research Database (Denmark)

Udgivelsesdato: 2008

KoreaScience (Korea)

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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...

International Nuclear Information System (INIS)

It has been acknowledged that river morphology and hydrology have been intensively altered due to the anthropic demands in floodplain land use and management, flood protection, promotion of navigability or energy production. Rivers were transformed in water highways, having lost contact with their surrounding floodplain as well as the plethora of ecological processes and occupants once thriving in these ecotonal zones. The identification of this emerging threat of morphological and hydrological alteration on ecological integrity adds further complexity in the exploitation of hydrosystem resources. These resources are heavily coveted and guarded by different lobbies each having strategic views on future project development. Stakeholders may want to promote hydro-electricity, ecologists a natural reserve, communes may wish to have an increased flood protection and leisure promoters a nautical center. As a result, the proposition of a river development project is ...

Energy Technology Data Exchange (ETDEWEB)

This presentation outlined the corporate history of the Ohmega Group, a small company from Gaspe, Quebec which offers consulting services to the automation and telecommunication sector. It was created in 1982 and has been involved with the wind power industry since 1996. The main services provided by Ohmega Group include electrical and mechanical construction and maintenance services. This paper also reviewed the benefits of using Supervisory Control and Data Acquisition (SCADA) systems in the wind power industry to monitor, control and collect data from wind turbines. The Ohmega Group has provided consulting services to Cartier Wind Energy Inc., a company that was awarded several wind turbine projects by Hydro-Quebec Distribution. The Ohmega Group applied the SCADA system at the Baie des Sables, Anse a Valleau and Carleton wind turbine arrays. The typical architecture of SCADA systems on a wind farm was presented along with ...

Energy Technology Data Exchange (ETDEWEB)

The results of the laboratory studies performed by CIEMAT with the FEBEX bentonite in the context of WP3.2 of the NF-PRO Project and of the Agreement ENRESA-CIEMAT Anexo V are presented and analysed in this report. They refer to the effect of the hydraulic gradient on the permeability of bentonite, the effect of the thermal gradient on the hydration kinetics of bentonite, and the repercussion of temperature on the hydro-mechanical properties of bentonite (swelling, permeability and water retention capacity). In all the cases the bentonite has been used compacted to densities expected in the engineered barrier of a high-level radioactive waste repository. The existence of threshold and critical hydraulic gradients has been observed, both of them dependent on bentonite density and water pressures. After more than seven years of hydration, the 40-cm high bentonite columns are far from full saturation, the thermal gradient additionally delaying the process, which is ...

Energy Technology Data Exchange (ETDEWEB)

Recent advances in elastic-plastic fracture mechanics have made it possible to assess the stability of cracks in ductile piping systems. These technological developments have been used by Ontario Hydro as the nucleus of an approach for demonstrating that CANDU primary heat transport piping systems will not break catastrophically; at worst they would leak at a detectable rate. This leak-before-break approach has been taken on the Darlington nuclear generating station as a design stage alternative to the provision of pipe whip restraints on large diameter, primary heat transport system piping. Positive conclusions reached via this approach are considered sufficient to exclude the requirement to provide protective devices, such as pipe whip restraints. In arriving at the proposed leak-before-break approach a review of current and proposed leak-before-break licensing positions of other jurisdictions (particularly those in the United States and the Federal Republic of ...

Energy Technology Data Exchange (ETDEWEB)

Electric utilities are actively seeking ways of optimizing the economics of their operations by improving productivity and reducing time and money spent on maintenance. Iberdrola, a Spanish utility, is using advanced machine condition-monitoring technology to centralize control and maintenance of its hydropower projects as a means of achieving those goals. The company is using a blend of technologies to supervise their projects from a regional control center. The monitoring scheme makes use of data from on-line, machine-condition monitors, displays from in-plant audio asnd video equipment, and analysis from the control center`s SCADA system.

Energy Technology Data Exchange (ETDEWEB)

Due to changed operational conditions and because of the increasing age of several hydro power plant components, there is an increasing risk of damages and the control of degradation mechanisms is of increasing significance. Therefore lifetime considerations for safety relevant components in pumped-storage plants become more and more important. The development of a lifetime management system, in conjunction with monitoring systems and specific surveillance for a group of pumped-storage power plants of different ages and in a wide range of power output is presented. The special focus is on the impact of fatigue strength considerations within this framework. The applied procedure will be described for typical mechanical components in pumped-storage plants exemplarily. (orig.)

International Nuclear Information System (INIS)

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

Energy Technology Data Exchange (ETDEWEB)

The studies undertaken by the B.C. Hydro company at the Canada showed that the existing system of hydroelectric power plants and transport cables will not be able to satisfy the increasing energy demand on the Vancouver island after 1985, and that the best solution will be the installation of a 525 kV transfer system from the continent. THe STK participated to the development and the immersion of this new system, the first in the world comprising submarine 525 kV transport parts. This paper presents the planning, the development, the submerging and the installation of two sections of submarine cable.

Science.gov (United States)

A growing number of pumped storage plants installed within the US brings attention to the increasing significance of pumped storage as a source of electrical generation capacity. Because of the special benefits this technology has to offer, hydroelectric pumped storage is an option that many utilities should consider for the supply of new capacity requirements. This article surveys the development and use of pumped storage in the US, and considers the potential for the future development of this technology. Although some of the problems that have occurred on recent projects highlight the role of pumped storage as a technological proving ground, the article puts forth the view that pumped storage is maturing to play a significant role in US electricity supply.

International Nuclear Information System (INIS)

The bituminzation of decontamination and ion exchange resin stripping wastes with four grades of asphalt was investigated to determine the effects of asphalt type on the properties of the final products. All waste forms deformed readily under light loads indicating they would flow if not restrained. It was observed in all cases that product leaching rates increased as the hardness of the asphalt used to treat the waste increased. If bituminization is adopted for any Ontario Hydro aqueous radioactive wastes they should be treated with soft asphalt to obtain optimum leaching resistance and mechanical stability during interim storage should be provided by a corrosion resistant container.

Energy Technology Data Exchange (ETDEWEB)

The report presents an integrated software system developed at the Norwegian Electric Power Research Institute (EFI), for production scheduling, maintenance handling, network security analysis, inflow forecasting, and load forecasting. The integrated software is being developed with focus on hydro-dominated power supply systems. In specific terms it is expected that application of the software will improve the operational decisions, and make the planning process more effective. The optimal scheduling of hydro resources poses severe computational problems in system operations planning. This necessitates problem decomposition. In the EFI approach, planning is split into three main levels: long-term, mid-term and short-term planning. The long-term planning aims at evaluating the seasonal and pluriannual handling of regional storages in view of firm power supply obligations, inflow statistics, main hydraulic and electric transit limitations, and ...

International Nuclear Information System (INIS)

Superconducting Cu-rich composites containing the A-15 compounds V_3Si or V_3Ga were made by the ''Tsuei'' process (melting into ingots followed by cold working and heat treatment). Superconducting transition temperatures of the composites were measured. X-ray diffraction analyses were performed. Microstructures were studied using both the optical metallograph and the scanning electron microscope. For some composites containing V_3Ga, the critical current densities as functions of transverse magnetic field up to 60 kG, and as functions of temperature from 4.2 to 12"0K were measured. It was found that the Tsuei process does not work for the composites containing V_3Si, but works satisfactorily for V_3Ga; reasons are discussed. Relations between measured properties and various metallurgical factors such as alloy compositions, cross-section reduction ratios, and heat treatment are discussed. The mechanism for the observed superconductivity in the materials is also discussed. It was also ...

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A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste.

International Nuclear Information System (INIS)

English 2009 p. 161-162 Brazil Paula, Viviane Silva de Almeida, Fabio

UK PubMed Central (United Kingdom)

Background and AimsIt is well known that genome size differs among species. However, information on the variation and dynamics of genome size in wild populations and on the early...Full Text Available

UK PubMed Central (United Kingdom)

AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available

Science.gov (United States)

The dynamic response characteristics of the VAWT rotor are important factors governing the safety and fatique life of VAWT systems. The principal problems are ...

Science.gov (United States)

... 23 Milstar 25 A Notional Battlespace For Dynamic Wireless Network Simulation/Testing ... Figure 16: GPS Satellite 23 Figure 17: Milstar Satellite 25 ...

Science.gov (United States)

S.M. Goltz; NASA Goddard Space Flight Center, Forest Ecosystem Dynamics Project ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

... Netherlands Kormendy, J. Dominion Astrophysical Observatory, Victoria, British

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Norwegian Open Research Archives (NORA)

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Indian Institute of Science Theses & Dissertations (India)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

Three aspects of the physical geographic environment of the Amazon Basin are considered: (1)

KoreaScience (Korea)

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CERN Document Server

In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of limit theorems for this object.

Energy Technology Data Exchange (ETDEWEB)

Two refrains heard in the current retail wheeling debate are that a restructuring of the electric utility industry is inevitable and that its consequences are unpredictable. Notwithstanding the benefits of open competition, there are specific disadvantages of unlimited retail wheeling for some existing independent facilities and especially for hydropower plants. A capital-intensive industry, hydropower is not well-postured to compete effectively in the short-term, against new technologies and fuel sources available in the current marketplace. Hydropower is flat out non-competitive on a price basis with available new capacity. Unless hydro is afforded the same government supports offered to other renewable energy sources, only municipal plants with access to subsidized financing rates and pumped storage plants are going to be built.

Energy Technology Data Exchange (ETDEWEB)

This third Missouri River Basin Commission report on Status of Electric Power in the Missouri River Basin provides information on the status of electric power generation, future needs, and potentials for meeting these needs. Information for this 1980 update is based upon available published information up to and including December 31, 1979. State and federal members of the Missouri River Basin Commission provided information for sections of the report and on legislative activities. Information is included on the planning and projected costs of hydro, nuclear and fossil-fuel power plants, pumped-storage plants, transmission systems, projected power demands, the environmental, socio-economic-cultural impacts of electric power generation, and regulations affecting energy development. (LCL)

Science.gov (United States)

The kWh model finds the kWh outputs of each plant and reservoir capacities of hydro and pumped storage plants and minimizes the sum of fixed charges for constructing the reservoirs and generating facilities, also the fuel costs of thermal and nuclear plants. It is a linear programming problem whose constants are represented by nonlinear functions of kW running capacity of each plant. The optimal pattern of nuclear and thermal units is found by solving the linear programming problem derived for the pumped storage and hydroplants. Excluding the upper bound constraints, the number of constraint equations are few and do not increase with the number of units, although the number of variables increases. The computing time increases only in proportion to the number of groupings of generating units. Sensitivity analysis can be done easily. The detailed operational behavior of each generating unit can be taken into account.

International Nuclear Information System (INIS)

Methodology, characteristics, features and results obtained for greenhouse gases within the recent Swiss LCA study 'Environmental Life-Cycle Inventories of Energy Systems' are presented. The focus of the study is on existing average Full Energy Chains (FENCHs) in the electricity generation mixes in Europe and in Switzerland. The systems, including coal (hard coal and lignite), oil, natural gas, nuclear and hydro, are discussed one by one as well as part of the electricity mixes. Photovoltaic systems are covered separately since they are not included in the electricity mixes. A sensitivity analysis on methane leakage during long-range transport via pipeline is shown. Whilst within the current study emissions are not attributed to specific countries, the main sectors contributing to the total GHGs emissions calculated for the various FENCHs are specified. (author). 10 refs, 10 figs, 9 tabs.

Energy Technology Data Exchange (ETDEWEB)

Since actinide mononitride has several superior thermal and neutronic properties, nitride fuel is considered as a candidate for future nuclear systems, such as advanced fast reactors and accelerator-driven system. Establishing reprocessing technology is one of key technologies for the development of nitride fuel cycle. In addition to general advantages of pyrochemical process, such as the potential for economy, radiation and proliferation resistance, recycling of N-15 in nitride fuel seems to be practical in comparison with conventional hydro-process. Following the electrochemical measurements of nitride fuel in LiCl-KCl molten salt, the experimental study on closing nitride fuel cycle has been carried out in JAEA by used of TRU nitride and burnup simulated nitride samples. Recent progress of the study is summarized in this paper.

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This paper describes the dielectric and accelerated aging tests on prototype {plus minus}500 kV dc oil-filled self-contained cables. The extensive test program was required to evaluate the High-Voltage cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper relates the main elements of the test program. It describes the required insulation levels, the characteristics of the cables supplied by three different manufacturers, as well as the cables' installation for the type tests and accelerated aging tests. Details of the test program and procedures followed to carry out the tests are given. Findings of the tests are also reported.

British Library Electronic Table of Contents (United Kingdom)

The number of spent fuel storage facilities in the world continues to increase because of "Wait and See" policies and delay of a permanent disposal plan. The temporary spent fuel storage concept is changing to a pre-disposal storage concept. Strengthened safety concepts are required for expanded spent fuel storage facilities and sites. The Korea Hydro and Nuclear Power Company is planning to construct a reinforced concrete MACSTOR-400 facility at Wolsung. In concrete dry spent fuel storage structures, cracks can occur due to radiant heat and environmental chloride. The likelihood of cracking increases over time. Research on changes in shielding performance from one collinear crack in the surface of a concrete facility has been carried out. However there is no research about public radiolog...

Energy Technology Data Exchange (ETDEWEB)

The emergence of new power electronics and improved battery technology has created renewed interest in Battery Energy Storage Systems (BESS). These new systems provide electric utilities with alternatives to conventional storage technologies, such as pumped hydro. BESs has the potential to provide substantial benefits in terms of energy management, improved voltage, spinning reserve and protection from interruptions when compared to large centralized storage. This paper describes a commercial, economically justified, application of the new Battery Energy Storage Systems which is presently under construction in the Metlakatla Power and Light system. The paper outlines the system performance requirements which lead to consideration of BESS as an option; the economic factors which provided the justification for BESS as an economic alternative; and the overall BES system design and performance.

Energy Technology Data Exchange (ETDEWEB)

The Burrard Thermal Generating Station is located at Port Moody, British Columbia, and burns natural gas to supply steam to six turbine units for generating up to 912 MW of electricity. The Burrard plant accounts for ca 8.7% of the provincial generating capability. Burrard is expected to continue to fill a vital role as a supplier of displaceable firm energy to the British Columbia Hydro system. In parallel with a renewed focus on Burrard from a system planning perspective, there have also been concerns about air pollution from the plant in the context of its possible effect on the region's air quality. To address this and other issues surrounding Burrard's future, B.C. Hydro established a project team to conduct a utilization study. The team's work focused on the role of Burrard in providing a reliable and profitable role in electricity generation, the options for dealing with the air quality issue, and the ...

International Nuclear Information System (INIS)

As part of the licensing process to construct a new 230 kV transmission line on an existing right-of-way in Manitoba, an electrical effects study was conducted in 1998. The study was part of the environmental assessment program crucial in obtaining government approval to construct the line. Some residents living adjacent to the new transmission circuit expressed concerns about alleged adverse health effects associated with long-term exposure to magnetic fields from high voltage transmission lines. In order to verify the accuracy of the predicted magnetic field levels submitted to the regulatory body in the the electrical effects study and to instill confidence in the residents of the affected communities, a three-year magnetic monitoring project was conducted between 2003 and 2005 along the right-of-way after the new 230kV transmission line was energized by Manitoba Hydro. This paper described the monitoring program, with reference to location; equipment; data ...

International Nuclear Information System (INIS)

This paper describes a long term course of research into the fundamentals of two phase flow regime dynamics that had lead to a differential description of regime properties. The development has included experiment, microscale simulation, and mathematical averaging to produce a dynamic equation for interfacial area.

UK PubMed Central (United Kingdom)

AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available

UK PubMed Central (United Kingdom)

Reliable characterization of locomotor dynamics of human walking is vital to understanding the neuromuscular control of human locomotion and disease diagnosis. However, the inherent oscillation and...Full Text Available

UK PubMed Central (United Kingdom)

Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification...Full Text Available

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

Energy Technology Data Exchange (ETDEWEB)

The aim of this project was to develop an understanding of the dynamical processes that evolve within an electric utility firm, and without it. This volume covers organizational dynamics and control, and planning under uncertainty. (DLC)

UK PubMed Central (United Kingdom)

Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) vertical transmission is important to enhance the accuracy of monitoring protocols for endemically infected...Full Text Available

UK PubMed Central (United Kingdom)

In order to maintain stable functionality in the face of continually changing input, neurones in the CNS must dynamically modulate their electrical characteristics. It has been hypothesized that in...Full Text Available

Science.gov (United States)

... 4.4+9 4.30 ds~ ;'* Page 24. Table 3 Ultimate Compressive Strength Data Static Dynamic Round Strength Range Strength Range No. Avg Rise 0No. ...

UK PubMed Central (United Kingdom)

SummaryWe develop a new class of models, dynamic conditionally linear mixed models, for longitudinal data by decomposing the within-subject covariance matrix using a special Cholesky...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This book contains over 20 selections. Some of the titles are: Continuum damage mechanics studies on the dynamic fracture of concrete; Dynamic compressive strength of cementitious materials; Rate-sensitivity of mode I and mode II fracture concrete; and An impact damage model of concrete.

UK PubMed Central (United Kingdom)

The realization theory linear dynamical systems, previously developed over a field, are extended to a large class of commutative rings. The principal result is that the existence criterion for a finite...Full Text Available

Science.gov (United States)

... Tunable semiconductor lasers are essential components for links employing optical frequency modulation (OFM) for enhanced dynamic range or ...

Science.gov (United States)

Wikileaks was inevitable. The Dynamics of. Information. Take advantage of the eddy currents. You can't step in the same river ...

Science.gov (United States)

... Dynamics Panel Executive AGARD 7 rue ... 4 AXIAL FLOW IN CORNERS AT SUPERSONIC ... AND HYPERSONIC FLOWS INCLUDING SEPARATION ...

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...

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The microstructures of magnesium AZ31 are examined following hot compression testing and annealing. The grain size, fraction dynamically recrystallized and, in a couple of cases, the crystallographic texture are reported. It was found that the progress of dynamic recrystallization is strongly sensitive to processing conditions but that the dynamically recrystallized grain size was less sensitive to stress than in other metals. It was also found that, for structures containing between 80 and 95% dynamic recrystallization, abnormal grain growth occurs during annealing. The crystallographic texture produced is also sensitive to the deformation conditions. (orig.)

KoreaScience (Korea)

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CERN Document Server

Full-Potential Electronic Structure Method

DEFF Research Database (Denmark)

Udgivelsesdato: 2008-Sep

Science.gov (United States)

... measurement. Power spectral density measurements are made by the dynamic signal analyzer for each channel. A cross power ...

Science.gov (United States)

Page 1. Adaptive system and method for responding to computer network security attacks Abstract A dynamic network security ...

Energy Technology Data Exchange (ETDEWEB)

We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultraslow logarithmic coarsening. {copyright} {ital 1999} {ital The American Physical Society}

International Nuclear Information System (INIS)

Dynamical models are presented that start with interstellar gas in an initial diffuse state and consider their gravitational collapse and the formation of dense cores. Frozen-in tangled magnetic fields are included to mimic forces that might oppose gravitational contraction and whose effectiveness may increase with increasing core densities. Results suggest the possibility that dense cloud cores may be dynamically evolving ephemeral objects, such that their lifespan at a given core density decreases as that density increases. 66 refs.

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.

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

International Nuclear Information System (INIS)

The effects of catalytic metal additives on the hydrogen desorption properties of the submicrocrystalline magnesium hydride (#beta#-MgH_2) formed after hydrogenation of the Mg + 10 wt.%X (X = V, Y, Zr) mechanically (ball) milled composites were studied. The composites with catalytic metals were processed by controlled mechanical milling (CMM) in the magneto-mill Uni Ball Mill 5 under protective Ar atmosphere. X-ray diffraction of the milled powders revealed the formation of Mg nanograins (50-60 nm range) interdispersed with the nanograined metal additives within the powder particles. Scanning electron microscopy showed particle size reduction after milling. After activation and hydrogenation in a Sieverts-type apparatus under about 2 MPa pressure of hydrogen, the tetragonal #beta#-MgH_2 hydride co-exists with the small amount of retained unreacted Mg phase and the small amount of MgO in all three composites. The #beta#-MgH_2 phase after hydrogenation is ...

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 are modest (typically below ten percent), leaving missing physics as the main source for large systematic ...

Energy Technology Data Exchange (ETDEWEB)

We consider the dynamics towards the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. Surprisingly few facts are known about the 'Mixmaster' dynamics of these models, while at the same time most of the commonly held beliefs are rather vague. In this paper, we use Mixmaster facts as a base to build an infrastructure that makes it possible to sharpen the main Mixmaster beliefs. We formulate explicit conjectures concerning (i) the past asymptotic states of type IX solutions and (ii) the relevance of the Mixmaster/Kasner map for generic past asymptotic dynamics. The evidence for the conjectures is based on a study of the stochastic properties of this map in conjunction with dynamical systems techniques. We use a dynamical systems formulation, since this approach has so far been the only successful path ...

International Nuclear Information System (INIS)

The results of the thermo-hydro-mechanical (THM) study of the FEBEX bentonite performed during FEBEX II are presented. The laboratory test program continued in part with the works carried out during FEBEX I, particularly in activities related to tests aimed to the calibration of the models, the acquisition of parameters by back-analysis and the improvement of the knowledge on the behaviour of expansive clays. But the program has also included tests on new areas: investigations about the influence of the microstructure changes in bentonite, of temperature and of the solute concentration on the behaviour of clay. Besides, several tests were proposed in order to understand the unexpected behaviour observed in the mock-up test, towards the end of year 2. Temperature effects on water retention curves in confined and unconfined conditions were determined, and swelling pressure, hydraulic conductivity and swelling and consolidation strains as a function of temperature ...

Energy Technology Data Exchange (ETDEWEB)

A novel system has been deployed to obtain geochemical samples of water and gas, at in situ pressure, during a geologic CO2 sequestration experiment conducted in the Frio brine aquifer in Liberty County, Texas. Project goals required high-frequency recovery of representative and uncontaminated aliquots of a rapidly changing two-phase (supercritical CO2-brine) fluid from 1.5 km depth. The datasets collected, using both the liquid and gas portions of the downhole samples, provide insights into the coupled hydro-geochemical issues affecting CO2 sequestration in brine-filled formations. While the basic premise underlying the U-Tube sampler is not new, the system is unique because careful consideration was given to the processing of the recovered two-phase fluids. In particular, strain gauges mounted beneath the high-pressure surface sample cylinders measured the ratio of recovered brine to supercritical CO2. A quadrupole mass spectrometer provided real-time gas ...

Energy Technology Data Exchange (ETDEWEB)

The recent attempt to degassify a self contained liquid filled (SCLF) cable in Ontario Hydro is described. In September 1989, there was a high pressure alarm on one phase of a SCLF 115 kV cable circuit. The direct buried cable circuit is about 1,890 m long with two joints and was installed in 1968. Oil samples from the cable had 10 to 12% gas content with high levels of hydrogen, methane, and ethane, and very low levels of carbon monoxide, carbon dioxide, and acetylene. From these results it was concluded that the gas was generated by low energy electrical discharges and the paper insulation was not degraded. Various utilities and cable manufacturers were contacted to find if they had experienced similar problems. The cable duct oil was flushed and gasified and the successive oil samples were analyzed in order to locate the gassing site. The joints were examined and oil samples were taken through holes drilled in the cable sheath. From the test results the problem ...

International Nuclear Information System (INIS)

Methodology based on probabilistic fracture mechanics (PFM) is finding increasing acceptability in demonstrating safety of Nuclear Power Plant (NPP) piping. In PFM, the methods of fracture mechanics and reliability theory are combined for assessing the reliability of components, which contain cracks. In this work, reliability assessment of Tarapur Atomic Power Plant (TAPP) 3-4 Primary Heat Transport (PHT) piping is done using PFM. Monte Carlo simulation with stratified sampling is used as a variance reduction technique. PFM model assumes a pre-existing circumferential surface crack before the start of plant operation. The crack grows in size during the lifetime of the plant due to the fatigue loading. This part-through wall crack having escaped hydro-test and pre-service inspection, may result in either a through wall flaw (leak) or may lead to the rupture of the piping. R6 method is used as failure criteria. Steam generator inlet (SGI), steam generator outlet ...

International Nuclear Information System (INIS)

Nuclear power plant has several safety features and each safety feature is based on the operation of pumps and valves. Therefore, it is an essential basis for the safety of nuclear power plant to keep operational readiness of pumps and valves by In-Service Test (IST). According to Ministry of Education, Science and Technology (MEST) Bulletin 2008-14, the safety functioned pumps and valves of all nuclear power plants of Korea Hydro and Nuclear Power Co. Ltd.(KHNP) have been tested to verify their performance of safety function. Each safety grade pump has own design requirement and should be tested to identify whether it could meet the requirement. Design requirements and test references of all safety grade pumps of Wolsung Nuclear Power Plant Unit 2 (Wolsung Unit 2) were examined in this study. And the results of the performance test of the pump were also compared to the design requirements of each pump.

Energy Technology Data Exchange (ETDEWEB)

The paper is concerned with the economic operation of power systems comprising pumped storage and thermal plants. In power systems, pumped storage plants may receive the energy required for pumping water either from the system in which they are integrated or from a neighbouring system. Therefore, two mathematical formulations of the problem are presented depending on the source of energy during pumping. In both cases, the problem is reduced to a non linear optimization problem. Two numerical techniques are suggested for the solution of this optimization problem, namely the Lagrangian Multipliers technique and the Rosen Gradient Projection technique. Numerical examples are presented to demonstrate the techniques. Although the Lagrangian Multipliers technique has the advantage of being a well known technique, however, computer wise, the Rosen Gradient Projection technique proves to be more efficient. The results of the numerical examples given show that mechanical and electrical losses ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

A transition from petroleum~derived jet fuels to blends with Fischer-Tropsch (F~T) fuels, and ultimately fully synthetic hydro-isomerized F-T fuels has raised concern about the fate of plasticizers in nitrile-butadiene rubber a-rings that are contacted by the fuels as this transition occurs. The partitioning of plasticizers and fuel molecules between nitrile a-rings and petroleum-derived, synthetic, and additized-synthetic jet fuels has been measured. Thermal desorption of o-rings soaked in the various jet fuels followed by gas chromatographic analysis with a mass spectrometric detector showed many of the plasticizer and stabilizer compounds were removed from the o-rings regardless of the contact fuel. Fuel molecules were observed to migrate into the o-rings for the petroleum-derived fuel as did both the fuel and additive for a synthetic F-T jet fuel additized with benzyl alcohol, but less for the unadditized synthetic fuel. The specific compounds or classes of ...

Energy Technology Data Exchange (ETDEWEB)

Independent power producers (IPPs) have had open access to existing power systems ever since the electric power industry was restructured and deregulated. IPPs are small-scale, distributed, and independently operated. Introducing an IPP to the power system can be beneficial to the existing power system because it can increase the security margin or reduce production cost and environmental pollution. The disadvantage is that some IPPs are not subject to dispatch control, consequently, they may reduce the network security. Often IPPs use co-generation, small-scale hydro, even fuel cells or other types of renewable energy sources. An evaluation of IPPs impact on an existing utility power system was determined in a modified IEEE 14 bus system. The total generating cost, environmental impact, transmission line margin, voltage profile, network congestion, security and other power quality measures were evaluated. It was concluded that on balance, an IPP improves the ...

Energy Technology Data Exchange (ETDEWEB)

Recent developments in heat pump technology have made geothermal-based heat exchange systems particularly well-suited for the heating and cooling needs of buildings even in cold climates. The principles of geothermally-coupled heat pump heating and cooling systems were presented. Results of an in-situ study conducted by Hydro-Quebec on the efficiency of the geothermal heat pump system installed at the Saint-Hyacinthe professional school were summarized. This investigation was meant to be a case study of the applicability of these new technologies to the needs of the Quebec market. After the first year of service, the Saint-Hyacinthe system clearly demonstrated its cost effectiveness over conventional systems. It was predicted that geothermal heat pump systems will gain in popularity in Quebec because they can fully meet the heating and cooling needs of public buildings at considerable cost reductions, besides offering considerable environmental benefits. 4 refs., 1 ...

Energy Technology Data Exchange (ETDEWEB)

Most of the information in this chapter is obtained from 1, 2, 3, 6, 8 and 9 annexes. It is worthwhile to clarify that in most of the cases they are estimations of the available resources, such as: trash, geothermal, solar energy, wind energy, biomass and mini and micro-hydro-energy. In several cases punctual measurements have been made, which do not represent a generic value of a national reserve. [Spanish] La mayor parte de la informacion en este capitulo es obtenida de los anexos 1, 2, 3, 6, 8 y 9. Cabe aclarar que en la mayoria de los casos son estimaciones de los recursos disponibles, tales como: la basura, la geotermia, la energia solar, la energia eolica, la biomasa y, la mini y la micro-hidroenergia. En varios casos se han realizado mediciones puntuales, las cuales no representan un valor generico de una reserva nacional.

Energy Technology Data Exchange (ETDEWEB)

In this study, the exhaust gas from a common-rail direct injection diesel engine was investigated both upstream and downstream warm-up catalytic converters (WCC). Three different types of ultra-low sulfur fuels (ethanol-diesel blend, ethanol-diesel blend with cetane improver and pure diesel) were tested in this study. The objective of the work was to study the engine performance and the formation of THC (total hydro carbon), CO (carbon monoxide), NO{sub x} (nitrogen oxides), smoke and PM (particulate matters) when using these fuels. THC and CO emissions of the ethanol-diesel blend fuels were slightly increased, and about 50-80% mean conversion efficiencies of THC and CO on catalysts were achieved in the ECE R49 13-mode cycle. Smoke was decreased by more than 42% in the entire ECE 13-mode cycles. From the measurement of scanning mobility particle sizer (SMPS) for the particle size range of 10-385 nm, the total number and total mass of the PM of the ethanol-diesel ...

Energy Technology Data Exchange (ETDEWEB)

Ontario's Countdown Acid Rain program was formulated in 1985 and placed an annual SO{sub 2} emissions cap of 885 kilotonnes over the province from 1994. Caps were placed on emissions from the Inco nickel/copper smelter in Sudbury, the Falconbridge nickel/copper smelter in Sudbury, the Algoma iron ore sintering plant in Wawa, and Ontario Hydro fossil-fuel plants province-wide. Semi-annual reports are required of the companies, with the 6th report outlining the final planning phase and the 7th and later reports outlining implementation progress. This document summarizes the contents of the 7th set of reports and the responses of the government review team to each company's efforts. All companies have begun implementing abatement plans outlined in the final planning phase reports of December 1988 at a rapid pace and are generally on track in controlling emissions. However, all 4 company reports lack the necessary detail for a complete review of the ...

Energy Technology Data Exchange (ETDEWEB)

A general overview is provided of the Wind Energy Research and Development Program (WERD) structure, status, and current perspectives, and a highlight of recent achievements. The broad objectives of WERD are to: determine under what circumstances wind energy can make a viable contribution to Canadian energy supplies; establish the technology of wind energy conversion systems (WECS) to appropriate Canadian conditions; and to encourage and support Canadian industrial initiatives in the design and manufacture of WECS for both domestic and export markets. Field trials supported by WERD include: six small scale Savonius/Darrieus vertical axis wind turbines (VAWT) rated at 1 to 3 kW installed throughout Canada; a 37 kW VAWT mechanically coupled to a 50 kW diesel-electric set as part of a 100 kW remote community powerplant; five 50 kW grid-coupled VAWT generating systems; a 224 kW VAWT grid-coupled system in cooperation with Hydro Quebec; and a parametric design study of ...

International Nuclear Information System (INIS)

A small break LOCA event simulation with no high pressure injection system available, known as International Atomic Energy Agency Standard Problem Exercise no. 4 (IAEA-SPE-4), was performed on the PMK-2 integral test facility in Budapest in 1993. This paper analyses the response of the PMK-2 facility, a model of VVER-440 nuclear power plant, using the latest released version MOD3.2.1.2 of the RELAP5 thermal-hydraulic code. After several years of the SPE-4 experiment analyses, many problems have emerged and been studied. Main goal of the present analyses was to study the main influencing parameters for adequate modelling of the hexagonal core channel with 19-rod bundle and phenomena during the core uncovery. Some influencing parameters have been identified, mostly on the primary side, but some also on the secondary side. This is exact simulation of main coolant pump coast down, hydro-accumulators water temperature and connections to the primary system. Some concern ...

International Nuclear Information System (INIS)

The issue of global warming was discussed with particular reference to the changes that may occur in the hydrological regime within the coming decades in response to predicted changes in climate. Flood events for the 2050 time horizon were investigated along with the consequences on water management and dam safety. Dams operated by Hydro-Quebec are used for flood control, water supply, recreational activities and hydroelectricity. As such, the electric utility relies on methods to evaluate the adaptability of current management plans to climate change. This paper presented the results of a study conducted at the Moisie River watershed, located in northern Quebec. The HSAMI hydrologic model was used to evaluate and compare the occurrences where stream flows and water levels exceed critical values in order to assess the effectiveness of management plans in both current and climate change scenarios. The study considered two different approaches on existing and future ...

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The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on pyrimidine ring saturation products (thymine glycol.and dihydrothymine), products ...

CERN Document Server

Several observational studies suggest that solar wind dynamic pressure fluctuations can drive magnetospheric ultra-low frequency (ULF) waves on the dayside. To investigate this causal relationship, we present results from Lyon-Fedder-Mobarry (LFM) global, three-dimensional magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphere interaction. These simulations are driven with synthetic solar wind input conditions, where idealized ULF dynamic pressure fluctuations are embedded in the upstream solar wind. In three of the simulations, a monochromatic, sinusoidal ULF oscillation is introduced into the solar wind dynamic pressure time series. In the fourth simulation, a continuum of ULF fluctuations over the 0-50 mHz frequency band is introduced into the solar wind dynamic pressure time series. In this numerical experiment, the idealized solar wind input conditions allow us to study only the ...

International Nuclear Information System (INIS)

This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational ...

British Library Electronic Table of Contents (United Kingdom)

Abstract This paper proposes and analyses the autoregressive conditional root (ACR) time-series model. This multivariate dynamic mixture autoregression allows for non-stationary epochs. It proves to be an appealing alternative to existing nonlinear models, e.g. the threshold autoregressive or Markov switching class of models, which are commonly used to describe nonlinear dynamics as implied by arbitrage in presence of transaction costs. Simple conditions on the parameters of the ACR process and its innovations are shown to imply geometric ergodicity, stationarity and existence of moments. Furthermore, consistency and asymptotic normality of the maximum likelihood estimators are established. An application to real exchange rate data illustrates the analysis.

CERN Document Server

Constrained quantum dynamics is used to propose a nonlinear dynamical equation for pure states of a generalized coarse-grained system. The relevant constraint is given either by the generalized purity or by the generalized invariant fluctuation, and the coarse-grained pure states correspond to the generalized coherent i.e. generalized nonentangled states. Open system model of the coarse-graining is discussed. It is shown that in this model and in the weak coupling limit the constrained dynamical equations coincide with an equation for pointer states, based on Hilbert-Schmidt distance, that was previously suggested in the context of the decoherence theory.

Energy Technology Data Exchange (ETDEWEB)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

Energy Technology Data Exchange (ETDEWEB)

Dynamic contingency analysis is certainly a demanding task in the context of dynamic performance evaluation. This paper presents the results of a test for checking the contingency screening capability of the IPEBS method. A brazilian 1100-bus, 112-gen system was used in the test; the ranking of the contingencies based on critical clearing times obtained with IPEBS, was compared with the ranking derived from detailed time-domain simulation. The results of this comparison encourages us to recommended the use of the method in industry applications, in a complementary basis to the current method of time domain simulation. (author) 5 refs., 1 fig., 2 tabs.

Science.gov (United States)

... Each beam finite element was derived using Hamilton's principle and the following basic assumptions: the beam has an arbitrary amount of pretwist ...

British Library Electronic Table of Contents (United Kingdom)

The ultrafast dynamics of the DNA fluorescent dye Sybr Green I (SG) has been studied in buffer, single-stranded (ssDNA), double-stranded (dsDNA) and triple-stranded DNA (tsDNA). The fluorescence quantum yield of SG increases dramatically when bound to DNA (including tsDNA). The fluorescence dynamics of the free SG has shown two decay components with 0.15-0.4ps and 1.3-2.1ps time constants, depending on the fluorescence wavelength. Upon binding to DNA, the dynamics becomes slower exhibiting four decay components. This is mainly due to the restriction of the internal motions of the dye caused by the relatively rigid environment of the dye complexed with DNA.

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, potential vorticity, and ...

Science.gov (United States)

... Information behavior in dynamic group work contexts: Interwoven situational awareness, dense social networks and contested collaboration in ...

Science.gov (United States)

Fluid dynamic design criteria for mercury condenser-subcooler component for sunflower power conversion system

Energy Technology Data Exchange (ETDEWEB)

Million-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si{sub 3}N{sub 4}. The authors find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si{sub 3}N{sub 4} as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si{sub 3}N{sub 4} reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si{sub 3}N{sub 4}. This is due to branching and pinning of the crack front by nanoscale microstructures.

UK PubMed Central (United Kingdom)

Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and...Full Text Available

CERN Document Server

Today, component oriented middlewares are used to design, develop and deploy easily distributed applications, by ensuring the heterogeneity, interoperability, and reuse of the software modules, and the separation between the business code encapsulated in the components and the system code managed by the containers. Several standards answer this definition such as: CCM (CORBA Component Model), EJB (Enterprise Java Beans) and .Net. However these standards offer a limited and fixed number of system services, removing any possibility to add system services or to reconfigure dynamically the middleware. Our works propose mechanisms to add and to adapt dynamically the system services, based on a reconfiguration language which is dynamically adaptable to the need of the reconfiguration, and on a tool of dynamic reconfiguration, a prototype was achieved for the OpenCCM platform, that is an implementation of the ...

International Nuclear Information System (INIS)

Real-time neutron radiography (RTNR) is now proving to be a valuable research tool in the study of hydrogenous fluid flow. One of the most significant advantages of neutron radiography is the ability to image hydrogenous substances (such as lubricants, coolants, and fuels) inside metallic materials such as aluminum and titanium engines. By using RTNR, one can then study dynamic events such as the movement of liquids inside these solids. The Phoenix Memorial Laboratory (PML) at the University of Michigan has recently developed and installed a facility dedicated to RTNR. The work at PML has shown that RTNR of dynamic events can provide information enabling the researcher to follow dynamic events that were previously impossible or impractical. This paper will show the variety of uses of RTNR presently being pursued at PML.

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

CERN Document Server

A recurrent idea in the study of complex systems is that optimal information processing is to be found near bifurcation points or phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also appear in the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic ...

Science.gov (United States)

By H. J. Grover, TV.S. Hyler, Paul Kuhn, Charles B. Landers, and ...... E. Watkins. The Effects on Dynamic Lateral Stability and Control of ...

CERN Document Server

In this paper we present a complete solution to the problem of multifractal analysis of multiple ergodic averages in the case of symbolic dynamics for functions of two variables depending on the first coordinate.

Science.gov (United States)

air traffic controllers at BOS tower and Terminal Radar Ap- .... Runway ) @ Runway. Buffer. Queue. Runway. Stochastic Delay. (M/1 server). (Runway to Fix). ,I, ...

CERN Document Server

The Kosambi-Cartan-Chern (KCC) theory represents a powerful mathematical method for the analysis of dynamical systems. In this approach one describes the evolution of a dynamical system in geometric terms, by considering it as a geodesic in a Finsler space. By associating a non-linear connection and a Berwald type connection to the dynamical system, five geometrical invariants are obtained, with the second invariant giving the Jacobi stability of the system. The Jacobi (in)stability is a natural generalization of the (in)stability of the geodesic flow on a differentiable manifold endowed with a metric (Riemannian or Finslerian) to the non-metric setting. In the present paper we review the basic mathematical formalism of the KCC theory, and present some specific applications of this method in general relativity, cosmology and astrophysics. In particular we investigate the Jacobi stability of the general relativistic static ...

International Nuclear Information System (INIS)

In conventional power plants trash-racks are provided at the intakes to protect the turbines. In pumped storage plants, the draft tube or tailrace must also have trash-racks to protect the units while pumping. Because the loads believed to cause many failures of trash-racks are dynamic in nature, it is important to understand the dynamic characteristics of trash-racks structures in general and a single rack in particular. The classical added-mass solution structure-fluid dynamic interaction is known as an approximate solution procedure. An accurate added-mass approach mixed with implementation in finite element framework is proposed. In this proposal, experimental conclusions, supported by theory, led to presentation of more accurate results in vibration of trash-racks. This numerical solution as a powerful method to solve such a complex problem can be employed to carry out dynamic characteristics of ...

UK PubMed Central (United Kingdom)

According to classical concepts of physiologic control, healthy systems are self-regulated to reduce variability and maintain physiologic constancy. Contrary to the predictions of homeostasis, however,...Full Text Available

Science.gov (United States)

... This Level 2 analysis will be somewhat less detailed, but experience in other fields including pipe whip 4 , locomotive dynamics, and nuclear fuel ...

British Library Electronic Table of Contents (United Kingdom)

The DN-tracking method is used to prove the existence of a closed trajectory in a quadratic system of ordinary differential equations in three dimensions.

Science.gov (United States)

rotor flow field in which the main rotor operates. The majority of ..... early separation predicted by their CFD code was ...... Airfoil, AGARD Fluid Dynamics Panel ...

International Nuclear Information System (INIS)

Russian 1987. p. 99-100. USSR Sabalyauskas, L.Yu. Vanagas, VV Guseva,

Science.gov (United States)

... A few applications, such as magnetic forming and levitation, have exploited the dynamic force pro- ducing capability of eddy currents. ...

UK PubMed Central (United Kingdom)

We develop and investigate numerically a thermodynamically consistent model of two-dimensional multicomponent vesicles in an incompressible viscous fluid. The model is derived using an energy...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

As usual a shipping terminal contains a header and its diameter is smaller than the main pipeline diameter. This diameter reduction amplifies the effects caused by hydraulic transients. It was noticed during simulations that check valves without dynamic modeling may introduce some error in the maximum pressure results without a dynamic model approach. The current paper uses commercial pipeline simulation software to model the dynamic behavior of the check valves. It was studied the header diameter influence and how the check valve model type may change the maximum pressure in the pipeline. It was proved that even a pipeline that works with low pressure and small elevation drop needs a detailed valve modeling to prevent the calculation of unreal pressure values in the region with diameter reduction. (author)

UK PubMed Central (United Kingdom)

In natural ecosystems, hundreds of species typically share the same environment and are connected by a dense network of interactions such as predation or competition for resources. Much is known about...Full Text Available

CERN Document Server

Disorder on the string theory landscape may significantly affect dynamics of eternal inflation leading to the possibility for some vacua on the landscape to become dynamically preferable over others. We systematically study effects of a generic disorder on the landscape starting by identifying a sector with built-in disorder -- a set of de Sitter vacua corresponding to compactifications of the Type IIB string theory on Calabi-Yau manifolds with a number of warped Klebanov-Strassler throats attached randomly to the bulk part of the Calabi-Yau. Further, we derive continuum limit of the vacuum dynamics equations on the landscape. Using methods of dynamical renormalization group we determine the late time behavior of the probability distribution for an observer to measure a given value of the cosmological constant. We find the diffusion of the probability distribution to significantly slow down in sectors ...

UK PubMed Central (United Kingdom)

ObjectiveTo determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.Full Text Available

Science.gov (United States)

... 4 maximum aggregate size. The effects of strain rate (up to 2.5 in./in./sec) on ultimate compressive strength were obtained. ...

British Library Electronic Table of Contents (United Kingdom)

Experimental results of quasi-static and dynamic fracture of particle-filled polymer composite (PFPCM) "ALTUGLAS EI CH25" with a matrix of polymethylmethacrylate (PMMA) are reported in this paper. PMMA matrix is filled with rubber particles, as result a shock-resistant transparent composite is produced. The main task was to investigate experimentally and theoretically the fracture toughness of this composite under static and dynamic loading. A high-rate loading has been created by impulse magnetic field. Analysis of fracture process and its relation with the load parameters and material microstructure have been established. Application of the original testing method enabled determination of fracture toughness at very short loading times and comparison of the results with material dynamic p...

UK PubMed Central (United Kingdom)

Human languages evolve continuously, and a puzzling problem is how to reconcile the apparent robustness of most of the deep linguistic structures we use with the evidence that they undergo possibly...Full Text Available

Science.gov (United States)

freeston@alexandria.sdc.ucsb.edu tel: 805-893-8589 fax: 805-893-3045. _. ,' .;_. .'_. Abstract. There has been no fundamental change in the dynamic indexing ...

Energy Technology Data Exchange (ETDEWEB)

Intracapsular femoral neck fractures remain unsolved fractures even after improvement in techniques of diagnosis and internal fixation. Individuals who sustain displaced femoral neck fractures are at high risk of developing avascular necrosis and non-union. Although several methods for predicting the viability of femoral head have been reported, they are not effective or widely used because of unreliability, potential complications and technical difficulties. Dynamic MRI was introduced in the recent past as a simple, non-invasive technique to predict the femoral head viability after the femoral neck fractures. In this study role of dynamic MRI was studied in 30 patients with 31 intracapsular femoral neck fractures. Fractures were divided in to three types according to dynamic curve patterns on MRI evaluation and were followed up for 6 months to 2 years to observe the final outcome. Sensitivity, Specificity and the Accuracy ...

International Nuclear Information System (INIS)

To further optimize thermo-hydraulic capability of HCSB-TBM, two different thermo-hydraulic schemes would be proposed and investigated by relevant calculating and simulating of thermo-dynamics in normal and peak heat flux condition. With computational fluid dynamics (CFD) code FLUENT, the actual temperature distribution of key components of HCSB-TBM is simulated. (authors)

Energy Technology Data Exchange (ETDEWEB)

This report describes the test of a dynamic phase compensation unit for a wind turbine with directly connected induction generators. The compensation unit is based on thyristor switched capacitors, where conventional wind turbine compensations use mechanical contactors to switch the capacitors. The influence on power quality analysed, and influence on component lifetime is discussed. Besides, simulation models in Matlab/Simulink are presented, including a flicker meter model. (au)

Energy Technology Data Exchange (ETDEWEB)

HANARO fuel test loop will be equipped in HANARO to obtain the development betterment of advanced fuel and materials through the irradiation test. The object of this study is to evaluate the structural integrity of FTL in-pool piping by investigating a dynamic analysis of the loop containing a postulated rupture section. The method to perform the dynamic analysis and structural integrity evaluation caused by the pipe whip in water environment can be a reference for a similar structural integrity evaluation. (author). 7 refs., 39 tabs., 34 figs.

Energy Technology Data Exchange (ETDEWEB)

Pile foundations are extensively used to support off-shore and on-shore structures. Under dynamic loads, the behavior of single pile is well understood. However the soil-pile-soil interaction studies are confusing, on which account the analyses do not necessarily predict response of the systems which may match satisfactorily with the performances. In this paper, the nature of dynamic loads is described, and solutions for soil-pile and pile-soil-pile interaction solutions by several authors are presented and a critical evaluation is made.

CERN Document Server

We study the dynamics of the scalar tensor cosmological model in the presence of tachyon field. In an alternative approach, in two exponential and power law form of the scalar field functions in the model, field equations are solved by simultaneously best fitting the model parameters with the most recent observational data. This approach gives us an observationally verified interpretation of the dynamics of the universe. We then discuss the best fitted of equation of state parameter, the statefinder parameters and the reconstructed scalar field in the model.

Energy Technology Data Exchange (ETDEWEB)

Molecular dynamics computer simulations of a dense nanocrystalline Nickel sample are performed on the parallel Cray T3 (EPFL-Lausanne). The sample contains 50 grains with an average size of 3 nm. By perturbing the relaxed configuration elastic and plastic properties are studied. (author) 1 fig., 1 ref.

UK PubMed Central (United Kingdom)

BackgroundCotton fiber development undergoes rapid and dynamic changes in a single cell type, from fiber initiation, elongation, primary and secondary wall biosynthesis, to fiber...Full Text Available

Science.gov (United States)

The dynamic behavior of electrooptic bistable devices with delayed feedback is investigated theoretically and experimentally. The operation principle of the system is analyzed by the method of iterated maps. Stable, bistable, periodic, higher periodic, and chaotic solutions are discussed and realized experimentally by using an integrated Mach-Zehnder interferometer on LiNbO3 as a basic nonlinear element. Taking into account the periodic modulator characteristic, the application of this device as a simple and fast bistable and monostable multivibrator is demonstrated. In addition, the synchronization properties of the astable multivibrator are investigated.

Energy Technology Data Exchange (ETDEWEB)

In connection with the ERP project 'Dynamic modelling of staged gasification processes' a gasification simulator has been constructed. The simulator consists of: a mathematical model of the gasification process developed at Technical University of Denmark, a user interface programme, IGSS, and a communication interface between the two programmes. (BA)

UK PubMed Central (United Kingdom)

Dynamic deformation and recovery responses of red blood cells (RBCs) to a cyclically reversing shear flow generated in a 30-μm clearance, with the peak shear stress of 53, 108,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

In this article, equations of motion of a manipulator are derived after consideration of the characteristics of the driving source. By considering a collision between a link and an object, and considering the active motion to absorb the kinetic energy of the object, the trajectories for saving energy are calculated by the iterative dynamic programming (IDP) method. The dynamic characteristics of manipulator control based on the trajectory for saving energy are also analyzed theoretically and investigated experimentally.

Energy Technology Data Exchange (ETDEWEB)

In the paper is studied the physics of a free electron laser (FEL) based on a two-frequency undulator (TFU) which induces large non linear effects, especially on the spectral dynamics. These effects are analyzed in an extended formalism where the spontaneous emission, the low-gain regime and the strong-field saturation regime are studied. Numerical simulations show that the optimized TFU generates a laser field having both a large extraction efficiency and a narrow spectrum.

Energy Technology Data Exchange (ETDEWEB)

Nutrient elements contained in litter fall flux, that of uptake flux and turnover rate had generally tended to increase with the increase in the Warmth Index, while the amount of nutrient in the A[sub 0] horizon and nutrient use efficiency did not. However, it is suggested that topographic and climatic aridity, and the amount of available and exchangeable phosphorus, calcium and magnesium greatly affect the nutrient dynamics in a each forest ecosystem as the Warmth Index increases. (J.P.N.).

International Nuclear Information System (INIS)

The dynamics of a general Bianchi type-IX model with three scale factors is examined. The matter content of the model is assumed to be comoving dust plus a positive cosmological constant. The model presents a critical point of saddle-center-center type in the finite region of phase space. This critical point engenders in the phase space dynamics the topology of stable and unstable four dimensional tubes RxS"3, where R is a saddle direction and S"3 is the manifold of unstable periodic orbits in the center-center sector. A general characteristic of the dynamical flow is an oscillatory mode about orbits of an invariant plane of the dynamics which contains the critical point and a Friedmann-Robertson-Walker (FRW) singularity. We show that a pair of tubes (one stable, one unstable) emerging from the neighborhood of the critical point towards the FRW singularity have homoclinic transversal crossings. The ...

Energy Technology Data Exchange (ETDEWEB)

This report presents and discusses results from Task 5 of the study ''Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,'' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. The FGD process is used to control the sulfur dioxide emissions which would result in acid rain if not controlled. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies developed for power plants involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the ...

CERN Document Server

Consider the flow of a thin layer of non-Newtonian fluid over a solid surface. I model the case of a viscosity that depends nonlinearly on the shear-rate; power law fluids are an important example, but the analysis here is for general nonlinear dependence. The modelling allows for large changes in film thickness provided the changes occur over a large enough lateral length scale. Modifying the surface boundary condition for tangential stress forms an accessible base for the analysis where flow with constant shear is a neutral critical mode, in addition to a mode representing conservation of fluid. Perturbatively removing the modification then constructs a model for the coupled dynamics of the fluid depth and the lateral momentum. For example, the results model the dynamics of gravity currents of non-Newtonian fluids even when the flow is not very slow.

British Library Electronic Table of Contents (United Kingdom)

A detailed knowledge about the dynamics of phytoplanktonic photosynthesis and respiration is crucial for the determination of primary productivity in open oceans as well as for biotechnological applications. The dynamics are best studied in photobioreactors that are able to simulate natural conditions in such, that light can be modulated not only diurnally but also mimicking effects of solar elevation angle from sunrise to sunset, variable cloudiness, light modulation in refractory sun flecks due to water waves, or light intermittence due to turbulent flow in dense suspensions. In addition, high performance photobioreactors ought to be able to monitor in real time photosynthetic and respiratory activities as well as culture growth. Here, we demonstrate performance of a newly designed bench...