Film boiling of saturated liquid flowing upward through a heated tube : high vapor quality range
Laverty, W. F.
1964-01-01T23:59:59.000Z
Film boiling of saturated liquid flowing upward through a uniformly heated tube has been studied for the case in which pure saturated liquid enters the tube and nearly saturated vapor is discharged. Since a previous study ...
Mussard, Bastien; Ángyán, János G
2015-01-01T23:59:59.000Z
Analytical forces have been derived in the Lagrangian framework for several random phase approximation (RPA) correlated total energy methods based on the range separated hybrid (RSH) approach, which combines a short-range density functional approximation for the short-range exchange-correlation energy with a Hartree-Fock-type long-range exchange and RPA long-range correlation. The RPA correlation energy has been expressed as a ring coupled cluster doubles (rCCD) theory. The resulting analytical gradients have been implemented and tested for geometry optimization of simple molecules and intermolecular charge transfer complexes, where intermolecular interactions are expected to have a non-negligible effect even on geometrical parameters of the monomers.
Low-energy parameters of neutron-neutron interaction in the effective-range approximation
Babenko, V. A.; Petrov, N. M. [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)
2013-06-15T23:59:59.000Z
The effect of the mass difference between the charged and neutral pions on the low-energy parameters of nucleon-nucleon interaction in the {sup 1}S{sub 0} state is studied in the effective-range approximation. On the basis of experimental values of the singlet parameters of neutron-proton scattering and the experimental value of the virtual-state energy for the neutron-neutron systemin the {sup 1}S{sub 0} state, the following values were obtained for the neutron-neutron scattering length and effective range: a{sub nn} = -16.59(117) fm and r{sub nn} = 2.83(11) fm. The calculated values agree well with present-day experimental results.
Enhanced convective and film boiling heat transfer by surface gas injection
Duignan, M.R.; Greene, G.A. [Brookhaven National Lab., Upton, NY (United States); Irvine, T.F., Jr. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering
1992-04-01T23:59:59.000Z
Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus_minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured [0 to 8.5 cm/s], the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.
Enhanced convective and film boiling heat transfer by surface gas injection
Duignan, M.R.; Greene, G.A. (Brookhaven National Lab., Upton, NY (United States)); Irvine, T.F., Jr. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering)
1992-04-01T23:59:59.000Z
Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured (0 to 8.5 cm/s), the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.
Senjean, Bruno; Jensen, Hans Jřrgen Aa; Fromager, Emmanuel
2015-01-01T23:59:59.000Z
The computation of excitation energies in range-separated ensemble density-functional theory (DFT) is discussed. The latter approach is appealing as it enables the rigorous formulation of a multi-determinant state-averaged DFT method. In the exact theory, the short-range density functional, that complements the long-range wavefunction-based ensemble energy contribution, should vary with the ensemble weights even when the density is held fixed. This weight dependence ensures that the range-separated ensemble energy varies linearly with the ensemble weights. When the (weight-independent) ground-state short-range exchange-correlation functional is used in this context, curvature appears thus leading to an approximate weight-dependent excitation energy. In order to obtain unambiguous approximate excitation energies, we simply propose to interpolate linearly the ensemble energy between equiensembles. It is shown that such a linear interpolation method (LIM) effectively introduces weight dependence effects. LIM has...
Window-based method for approximating the Hausdorff in three-dimensional range imagery
Koch, Mark W. (Albuquerque, NM)
2009-06-02T23:59:59.000Z
One approach to pattern recognition is to use a template from a database of objects and match it to a probe image containing the unknown. Accordingly, the Hausdorff distance can be used to measure the similarity of two sets of points. In particular, the Hausdorff can measure the goodness of a match in the presence of occlusion, clutter, and noise. However, existing 3D algorithms for calculating the Hausdorff are computationally intensive, making them impractical for pattern recognition that requires scanning of large databases. The present invention is directed to a new method that can efficiently, in time and memory, compute the Hausdorff for 3D range imagery. The method uses a window-based approach.
The correlation of nucleate boiling burn-out data
Griffith, P.
1957-01-01T23:59:59.000Z
A dimensionless correlation is developed for nucleate boiling buzrnout data including the following ranges of variables. Fluids - Water Bensene n - Heptane n - Pentane Ethanol Pressure - 0.0045 to 0.96 of critical pressure ...
RELAP5/MOD3 subcooled boiling model assessment
Devkin, A.S.; Podosenov, A.S. [Russian Research Center, Moscow (Russian Federation). Nuclear Safety Inst.
1998-05-01T23:59:59.000Z
This report presents the assessment of the RELAP5/Mod3 (5m5 version) code subcooled boiling process model which is based on a variety of experiments. The accuracy of the model is confirmed for a wide range of regime parameters for the case of uniform heating along the channel. The condensation rate is rather underpredicted, which may lead to considerable errors in void fraction behavior prediction in subcooled boiling regimes for nonuniformly or unheated channels.
A study of electrowetting-assisted boiling
Bralower, Harrison L. (Harrison Louis)
2011-01-01T23:59:59.000Z
The classical theory of boiling heat transfer based on bubble dynamics is explained and includes a full derivation of the Rohsenow boiling correlation. An alternative, more accurate correlation for determining boiling heat ...
Aquino, Fredy W.; Govind, Niranjan; Autschbach, Jochen
2011-10-01T23:59:59.000Z
Density functional theory (DFT) calculations of NMR chemical shifts and molecular g-tensors with Gaussian-type orbitals are implemented via second-order energy derivatives within the scalar relativistic zeroth order regular approximation (ZORA) framework. Nonhybrid functionals, standard (global) hybrids, and range-separated (Coulomb-attenuated, long-range corrected) hybrid functionals are tested. Origin invariance of the results is ensured by use of gauge-including atomic orbital (GIAO) basis functions. The new implementation in the NWChem quantum chemistry package is verified by calculations of nuclear shielding constants for the heavy atoms in HX (X=F, Cl, Br, I, At) and H2X (X = O, S, Se, Te, Po), and Te chemical shifts in a number of tellurium compounds. The basis set and functional dependence of g-shifts is investigated for 14 radicals with light and heavy atoms. The problem of accurately predicting F NMR shielding in UF6-nCln, n = 1 to 6, is revisited. The results are sensitive to approximations in the density functionals, indicating a delicate balance of DFT self-interaction vs. correlation. For the uranium halides, the results with the range-separated functionals are mixed.
Flow boiling test of GDP replacement coolants
Park, S.H. [comp.
1995-08-01T23:59:59.000Z
The tests were part of the CFC replacement program to identify and test alternate coolants to replace CFC-114 being used in the uranium enrichment plants at Paducah and Portsmouth. The coolants tested, C{sub 4}F{sub 10} and C{sub 4}F{sub 8}, were selected based on their compatibility with the uranium hexafluoride process gas and how well the boiling temperature and vapor pressure matched that of CFC-114. However, the heat of vaporization of both coolants is lower than that of CFC-114 requiring larger coolant mass flow than CFC-114 to remove the same amount of heat. The vapor pressure of these coolants is higher than CFC-114 within the cascade operational range, and each coolant can be used as a replacement coolant with some limitation at 3,300 hp operation. The results of the CFC-114/C{sub 4}F{sub 10} mixture tests show boiling heat transfer coefficient degraded to a minimum value with about 25% C{sub 4}F{sub 10} weight mixture in CFC-114 and the degree of degradation is about 20% from that of CFC-114 boiling heat transfer coefficient. This report consists of the final reports from Cudo Technologies, Ltd.
Subcooled flow boiling of fluorocarbons
Murphy, Richard Walter
1971-01-01T23:59:59.000Z
A study was conducted of heat transfer and hydrodynamic behavior for subcooled flow boiling of Freon-113, one of a group of fluorocarbons suitable for use in cooling of high-power-density electronic components. Problems ...
Enhanced boiling heat transfer in horizontal test bundles
Trewin, R.R.; Jensen, M.K.; Bergles, A.E.
1994-08-01T23:59:59.000Z
Two-phase flow boiling from bundles of horizontal tubes with smooth and enhanced surfaces has been investigated. Experiments were conducted in pure refrigerant R-113, pure R-11, and mixtures of R-11 and R-113 of approximately 25, 50, and 75% of R-113 by mass. Tests were conducted in two staggered tube bundles consisting of fifteen rows and five columns laid out in equilateral triangular arrays with pitch-to-diameter ratios of 1.17 and 1.5. The enhanced surfaces tested included a knurled surface (Wolverine`s Turbo-B) and a porous surface (Linde`s High Flux). Pool boiling tests were conducted for each surface so that reference values of the heat transfer coefficient could be obtained. Boiling heat transfer experiments in the tube bundles were conducted at pressures of 2 and 6 bar, heat flux values from 5 to 80 kW/m{sup 2}s, and qualities from 0% to 80%, Values of the heat transfer coefficients for the enhanced surfaces were significantly larger than for the smooth tubes and were comparable to the values obtained in pool boiling. It was found that the performance of the enhanced tubes could be predicted using the pool boiling results. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures was found to depend on the difference between the molar concentration in the liquid and vapor.
Mardirossian, Narbe; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Department of Chemistry, University of California, Berkeley and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Department of Chemistry, University of California, Berkeley and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2014-05-14T23:59:59.000Z
The limit of accuracy for semi-empirical generalized gradient approximation (GGA) density functionals is explored by parameterizing a variety of local, global hybrid, and range-separated hybrid functionals. The training methodology employed differs from conventional approaches in 2 main ways: (1) Instead of uniformly truncating the exchange, same-spin correlation, and opposite-spin correlation functional inhomogeneity correction factors, all possible fits up to fourth order are considered, and (2) Instead of selecting the optimal functionals based solely on their training set performance, the fits are validated on an independent test set and ranked based on their overall performance on the training and test sets. The 3 different methods of accounting for exchange are trained both with and without dispersion corrections (DFT-D2 and VV10), resulting in a total of 491 508 candidate functionals. For each of the 9 functional classes considered, the results illustrate the trade-off between improved training set performance and diminished transferability. Since all 491 508 functionals are uniformly trained and tested, this methodology allows the relative strengths of each type of functional to be consistently compared and contrasted. The range-separated hybrid GGA functional paired with the VV10 nonlocal correlation functional emerges as the most accurate form for the present training and test sets, which span thermochemical energy differences, reaction barriers, and intermolecular interactions involving lighter main group elements.
Pool boiling on nano-finned surfaces
Sriraman, Sharan Ram
2009-05-15T23:59:59.000Z
The effect of nano-structured surfaces on pool boiling heat transfer is explored in this study. Experiments are conducted in a cubical test chamber containing fluoroinert coolant (PF5060, Manufacturer: 3M Co.) as the working fluid. Pool boiling...
Wojdylo, John [School of Physics, University of Western Australia, 35 Stirling Hwy, Crawley 6009 WA (Australia)
2010-06-15T23:59:59.000Z
The properties of many-particle quantum systems can change drastically if the particles are attractive overall (e.g. a Fermi gas of atoms can become a Bose gas of dimers). It is therefore important to know if pairing can occur, particularly in the dilute strong coupling limit. We focus on cold helium atoms, which interact weakly via a finite-range potential. This problem can, of course, be approached numerically. However, with the extremely delicate balance of kinetic and potential energy, how do we know we can trust the number (e.g. the binding energy) that the computer produces? We could try several numerical schemes implemented with utmost care, and if they agree, we might feel confident in the answer. However, this does not constitute a proof: each scheme could be making the same mistake. We implement, instead, an analytical approach with guaranteed error bounds, which exploits an accident of Nature; namely, a small parameter in the pair wave function that invites the use of asymptotic theory. Leveraging the true long-range form of the wave function, a variational approach for bounds on the binding energy and dimer size produces integrals of a form that is well-known in the theory of asymptotic approximation of integrals. Despite being 'merely' a variational method, the upper bound obtained for the binding energy of the {sup 4}He{sub 2} dimer in three dimensions is remarkably close to a recent experimental value of 1.7 mK. Moreover, the calculated variational dimer size is also good. We have demonstrated the analytical framework by simulating the search for {sup 3}He{sub 2}, {sup 4}He{sub 2} and {sup 3}He-{sup 4}He dimers in one, two and three dimensions. The details will be published elsewhere.
Zaman, A.A.; McNally, T.W.; Fricke, A.L. [Univ. of Florida, Gainesville, FL (United States)] [Univ. of Florida, Gainesville, FL (United States)
1998-01-01T23:59:59.000Z
Vapor-liquid equilibria and boiling point elevation of slash pine kraft black liquors over a wide range of solid concentrations (up to 85% solids) has been studied. The liquors are from a statistically designed pulping experiment for pulping slash pine in a pilot scale digester with four cooking variables of effective alkali, sulfidity, cooking time, and cooking temperature. It was found that boiling point elevation of black liquors is pressure dependent, and this dependency is more significant at higher solids concentrations. The boiling point elevation data at different solids contents (at a fixed pressure) were correlated to the dissolved solids (S/(1 {minus} S)) in black liquor. Due to the solubility limit of some of the salts in black liquor, a change in the slope of the boiling point elevation as a function of the dissolved solids was observed at a concentration of around 65% solids. An empirical method was developed to describe the boiling point elevation of each liquor as a function of pressure and solids mass fraction. The boiling point elevation of slash pine black liquors was correlated quantitatively to the pulping variables, using different statistical procedures. These predictive models can be applied to determine the boiling point rise (and boiling point) of slash pine black liquors at processing conditions from the knowledge of pulping variables. The results are presented, and their utility is discussed.
Efficient Cooling in Engines with Nucleate Boiling
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
with Nucleate Boiling Principal Investigator: Wenhua Yu Coworkers: D. France and R. Smith Energy Systems Division Argonne National Laboratory OVT Merit Review February 28, 2008...
Enhancement of Pool Boiling Heat Transfer in Confined Space
Hsu, Chia-Hsiang
2014-05-05T23:59:59.000Z
Pool boiling is an effective method used in many technical applications for a long time. Its highly efficient heat transfer performance results from not only the convection effect but also the phase change process in pool boiling. Pool boiling...
Anastasiya V. Pimenova; Denis S. Goldobin
2014-10-20T23:59:59.000Z
We consider the problem of boiling of the direct contact of two immiscible liquids. An intense vapour formation at such a direct contact is possible below the bulk boiling points of both components, meaning an effective decrease of the boiling temperature of the system. Although the phenomenon is known in science and widely employed in technology, the direct contact boiling process was thoroughly studied (both experimentally and theoretically) only for the case where one of liquids is becoming heated above its bulk boiling point. On the contrary, we address the case where both liquids remain below their bulk boiling points. In this paper we construct the theoretical description of the boiling process and discuss the actualisation of the case we consider for real systems.
PACCAR CRADA: Experimental Investigation in Coolant Boiling in...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
PACCAR CRADA: Experimental Investigation in Coolant Boiling in a Half-Heated Circular Tube PACCAR CRADA: Experimental Investigation in Coolant Boiling in a Half-Heated Circular...
CRADA with PACCAR Experimental Investigation in Coolant Boiling...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
PACCAR Experimental Investigation in Coolant Boiling in a Half-Heated Circular Tube CRADA with PACCAR Experimental Investigation in Coolant Boiling in a Half-Heated Circular Tube...
Acoustically Enhanced Boiling Heat Transfer
Z. W. Douglas; M. K. Smith; A. Glezer
2008-01-07T23:59:59.000Z
An acoustic field is used to increase the critical heat flux (CHF) of a flat-boiling-heat-transfer surface. The increase is a result of the acoustic effects on the vapor bubbles. Experiments are performed to explore the effects of an acoustic field on vapor bubbles in the vicinity of a rigid-heated wall. Work includes the construction of a novel heater used to produce a single vapor bubble of a prescribed size and at a prescribed location on a flatboiling surface for better study of an individual vapor bubble's reaction to the acoustic field. Work also includes application of the results from the single-bubble heater to a calibrated-copper heater used for quantifying the improvements in CHF.
Nucleate boiling bubble growth and departure
Staniszewski, Bogumil E.
1959-01-01T23:59:59.000Z
The vapor bubble formation on the heating surface during pool boiling has been studied experimentally. Experiments were made at the atmospheric pressure 28 psi and 40 psi, using degassed distilled water and ethanol. The ...
Void volumes in subcooled boiling systems
Griffith, P.
1958-01-01T23:59:59.000Z
Introduction: Knowledge of the pressure drop in a channel and the resulting flow redistribution is essential in predicting the performance of a nuclear reactor. The pressure drop in a channel which is experiencing boiling ...
Pool boiling heat transfer characteristics of nanofluids
Kim, Sung Joong, Ph. D. Massachusetts Institute of Technology
2007-01-01T23:59:59.000Z
Nanofluids are engineered colloidal suspensions of nanoparticles in water, and exhibit a very significant enhancement (up to 200%) of the boiling Critical Heat Flux (CHF) at modest nanoparticle concentrations (50.1% by ...
Pool boiling on nano-finned surfaces
Sriraman, Sharan Ram
2008-10-10T23:59:59.000Z
is explored in this study. Experiments are conducted in a cubical test chamber containing fluoroinert coolant (PF5060, Manufacturer: 3M Co.) as the working fluid. Pool boiling experiments are conducted for saturation and subcooled conditions. Three...). .................................................................................................68 Fig. 19. Plots comparing the heat flux through the enhanced test surfaces (qw”) with the heat flux through the bare test surface (qb”) under 10 °C sub-cooling condition for both nulceate and film boiling regimes. Heat flux data...
Boiling water reactor control rod
Wilson, J.F.; Doshi, P.K.
1986-12-23T23:59:59.000Z
This patent describes a control rod for a boiling water type nuclear power reactor, the improvement comprising: (a) an elongated central stem defining a longitudinally extending internal central gas plenum; (b) blades connected to and extending along and radially outward from the stem, each blade including an elongated body portion extending along the stem and terminating in an end tip portion; (c) means defining a series of internal cavities in each of the blades, the cavities being arranged in columns and rows across the length and width of the body and tip portions of the blade; (d) pellets of neutron absorbing material, each disposed within one of the cavities with each of the cavities being oversized in relation to the size of the pellet disposed therein to allow extra space for swelling of the pellet. The cavities and the pellets disposed therein are arranged to define a longer, constant worth section generally coextensive with the body portion of the blade and a shorter, reduced worth section generally coextensive with the end tip portion of the blade; and (e) means defined within each blade communicating each of the cavities with the central gas plenum for allowing any gases generated by irradiation of the pellets to expand from the cavities into the plenum.
Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel
Aussillous, Pascale
Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel July 2008 Keywords: Boiling Microchannels Visualisation Flow boiling instabilities Heat transfer a b intensification heat removal. Flow boiling heat transfer in microchannel geometry and the associated flow
Transition boiling heat transfer from a horizontal surface
Berenson Paul Jerome
1960-01-01T23:59:59.000Z
An experiment, utilising a condensing fluid as the heat source, was performed to determine the heat flux vs. temperature difference curve for transition pool boiling from a horisontal surface. The boiling cure was determined ...
Boiling and condensation in a liquid-filled enclosure
Bar-Cohen Avram
1971-01-01T23:59:59.000Z
A combined experimental and analytical investigation of boiling and condensation in a liquid-filled enclosure, with water and Freon- 113 as the working fluids, is described. The operating characteristics of a boiling system, ...
PNNL Enhanced Pool-Boiling Heat Transfer Using Nanostructured Surfaces
None
2012-12-31T23:59:59.000Z
Close-up video of boiling taking place on a nanostructured surface in a controlled laboratory experiment.
Yu, W.; France, D. M.; Routbort, J. L. (Energy Systems)
2011-01-19T23:59:59.000Z
Because of its order-of-magnitude higher heat transfer rates, there is interest in using controllable two-phase nucleate boiling instead of conventional single-phase forced convection in vehicular cooling systems to remove ever increasing heat loads and to eliminate potential hot spots in engines. However, the fundamental understanding of flow boiling mechanisms of a 50/50 ethylene glycol/water mixture under engineering application conditions is still limited. In addition, it is impractical to precisely maintain the volume concentration ratio of the ethylene glycol/water mixture coolant at 50/50. Therefore, any investigation into engine coolant characteristics should include a range of volume concentration ratios around the nominal 50/50 mark. In this study, the forced convective boiling heat transfer of distilled water and ethylene glycol/water mixtures with volume concentration ratios of 40/60, 50/50, and 60/40 in a 2.98-mm-inner-diameter circular tube has been investigated in both the horizontal flow and the vertical flow. The two-phase pressure drop, the forced convective boiling heat transfer coefficient, and the critical heat flux of the test fluids were determined experimentally over a range of the mass flux, the vapor mass quality, and the inlet subcooling through a new boiling data reduction procedure that allowed the analytical calculation of the fluid boiling temperatures along the experimental test section by applying the ideal mixture assumption and the equilibrium assumption along with Raoult's law. Based on the experimental data, predictive methods for the two-phase pressure drop, the forced convective boiling heat transfer coefficient, and the critical heat flux under engine application conditions were developed. The results summarized in this final project report provide the necessary information for designing and implementing nucleate-boiling vehicular cooling systems.
Boiling of nuclear liquid in the micro-canonical ensemble
-dependence of the nuclear symmetry energy and the critical temperature of 1 #12;Boiling of nuclear liquid in the microBoiling of nuclear liquid in the micro-canonical ensemble K. Miyazaki E-mail: miyazakiro@rio.odn.ne.jp Abstract New calculus of the liquid-gas phase transition is developed for the boiling of nuclear liquid
Mechanism of nucleate pool boiling heat transfer to sodium and the criterion for stable boiling
Shai, Isaac
1967-01-01T23:59:59.000Z
A comparison between liquid metals and other common fluids, like water, is made as regards to the various stages of nucleate pool boiling. It is suggested that for liquid metals the stage of building the thermal layer plays ...
Transition from film boiling to nucleate boiling in forced convection vertical flow
Iloeje, Onwuamaeze C.
1972-01-01T23:59:59.000Z
The mechanism of collapse of forced cnnvection annular vertical flow film boiling, with liquid core, is investigated using liquid nitrogen at low pressures. The report includes the effect of heat flux from the buss bar. ...
Boiling heat transfer in a vertical microchannel: Local estimation during flow boiling with a non the results of experimental and numerical studies concerning boiling heat transfer inside vertical in minichannels for several gravity levels (µg, 1g, 2g). To fully understand the high heat transfer potential
Boiling heat transfer with three fluids in small circular and rectangular channels
Tran, T.N.; Wambsganss, M.W. [Argonne National Lab., IL (United States); France, D.M. [Illinois Univ., Chicago, IL (United States). Dept. of Mechanical Engineering
1995-01-01T23:59:59.000Z
Small circular and noncircular channels are representative of flow passages act evaporators and condensers. This report describes results of an ental study on heat transfer to the flow boiling of refrigerants (R-12) and refrigerant-134a (R-134a) in a small horizontal circular-cross-section tube. The tube diameter of 2.46 mm was chosen to approximate the hydraulic diameter of a 4.06 {times} 1.70 mm rectangular channel previously studied with R-12, and a 2.92-mm-diameter circular tube previously studied with R-113. The objective of this study was to assess the effects of channel geometry and fluid properties on the heat transfer coefficient and to obtain additional insights relative to the heat transfer mechanism(s). The current circular flow channel for the R-12 and R-134a tests was made of brass and had an overall length of 0.9 in. The channel wall was electrically heated, and thermocouples were installed on the channel wall and in the bulk fluid stream. Voltage taps were located at the same axial locations as the stream thermocouples to allow testing over an exit quality range to 0.94 and a large range of mass flux (58 to 832 kg/m{sup 2}s) and heat flux (3.6 to 59 kW/m{sup 2}). Saturation pressure was nearly constant, averaging 0.82 MPa for most of the testing, with some tests performed at a lower pressure of 0.4--0.5 MPa. Local heat transfer coefficients were determined experimentally as a function of quality along the length of the test section. Analysis of all data for three tubes and three fluids supported the conclusion that a nucleation mechanism dominates for flow boiling in small channels. Nevertheless, a convection-dominant region was obtained experimentally in this study at very low values of wall superheat (< {approx} 2.75{degrees}C). The circular and rectangular tube data for three fluids were successfully correlated in the nucleation-dominant region.
POOL BOILING OF HIGH-FREQUENCY CONDUCTORS
Wright, S. E. (Spencer E.); Konecni, S. (Snezana); Ammerman, C. N. (Curtt N.); Sims, J. R. (James R.)
2001-01-01T23:59:59.000Z
This study presents development of a unique, powerful method for cooling high-frequency, AC conductors that can benefit end users of transformer windings, electrical machine windings, and magnet coils. This method of heat removal involves boiling a dielectric, fluorinert refrigerant that is in direct contact with litz wire conductors. A pool boiling test vessel is constructed, which provides for temperature control of the pool of fluorinert liquid. The test vessel is fitted with viewing ports so that the experiments are observed and studied with the aid of high-speed photography. Tests are performed on a variety of litz wire conductors. The boiling heat transfer coefficient is dependent on the conductor surface roughness. The size of the features on the conductor surface depends on the single-strand wire gage from which the conductor is constructed. All tests are performed with the conductors mounted horizontally. These tests are performed using a DC power supply. The results of these experiments will aid in the design of future cooling systems.
Nonlinear dynamics and chaos in boiling water reactors
March-Leuba, J.
1988-01-01T23:59:59.000Z
There are currently 72 commercial boiling water reactors (BWRs) in operation or under construction in the western world, 37 of them in the United States. Consequently, a great effort has been devoted to the study of BWR systems under a wide range of plant operating conditions. This paper represents a contribution to this ongoing effort; its objective is to study the basic dynamic processes in BWR systems, with special emphasis on the physical interpretation of BWR dynamics. The main thrust in this work is the development of phenomenological BWR models suited for analytical studies performed in conjunction with numerical calculations. This approach leads to a deeper understanding of BWR dynamics and facilitates the interpretation of numerical results given by currently available sophisticated BWR codes. 6 refs., 14 figs., 2 tabs.
Wirtz, Richard A.
structures having wide ranging porosity and pore size. When deployed as a surface enhancement in a boiling pool-boiling experiments at one atmosphere and sub-atmospheric pressure assess the utility of fine factor of lamination [dimensionless] CHF = critical heat flux [W/cm2 ] Dh = pore hydraulic diameter [µm
actual coolant boiling: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
abwr advanced boiling: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
advanced boiling curve: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
automatic boiling water: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
advanced boiling water: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
Cooling Boiling in Head Region - PACCAR Integrated Underhood...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Integrated External Aerodynamic and Underhood Thermal Analysis for Heavy Vehicles CRADA with PACCAR Experimental Investigation in Coolant Boiling in a Half-Heated Circular...
Conversion of direct process high-boiling residue to monosilanes
Brinson, Jonathan Ashley (Vale of Glamorgan, GB); Crum, Bruce Robert (Madison, IN); Jarvis, Jr., Robert Frank (Midland, MI)
2000-01-01T23:59:59.000Z
A process for the production of monosilanes from the high-boiling residue resulting from the reaction of hydrogen chloride with silicon metalloid in a process typically referred to as the "direct process." The process comprises contacting a high-boiling residue resulting from the reaction of hydrogen chloride and silicon metalloid, with hydrogen gas in the presence of a catalytic amount of aluminum trichloride effective in promoting conversion of the high-boiling residue to monosilanes. The present process results in conversion of the high-boiling residue to monosilanes. At least a portion of the aluminum trichloride catalyst required for conduct of the process may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.
A study of boiling water flow regimes at low pressures
Fiori, Mario P.
1966-01-01T23:59:59.000Z
"A comprehensive experimental program to examine flow regimes at pressures below 100 psia for boiling of water in tubes was carried out. An electrical probe, which measures the resistance of the fluid between the centerline ...
Film Boiling on Downward Quenching Hemisphere of Varying Sizes
Chan S. Kim; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim
2004-04-01T23:59:59.000Z
Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.
Pressure drop with surface boiling in small-diameter tubes
Dr?mer, Thomas
1964-01-01T23:59:59.000Z
Pressure drop for water flowing in small-diameter tubes under isothermal, nonboiling, and surface-boiling conditions was investigated. Experimental results for local pressure gradient and heattransfer coefficients are ...
Suppression and Enhancement of Boiling Associated with Multiple Droplet Impingement
Yang, Yuxuan
2014-05-01T23:59:59.000Z
are at play simultaneously. Furthermore, experiments with single streams of droplets have not been able to elucidate the effects of the onset of boiling (ONB) during the droplet impingement process. Therefore, efforts have been undertaken to consider...
Pool boiling studies on nanotextured surfaces under highly subcooled conditions
Sathyamurthi, Vijaykumar
2009-05-15T23:59:59.000Z
Subcooled pool boiling on nanotextured surfaces is explored in this study. The experiments are performed in an enclosed viewing chamber. Two silicon wafers are coated with Multiwalled Carbon Nanotubes (MWCNT), 9 microns (Type-A) and 25 microns (Type...
Thermal boundary layer development in dispersed flow film boiling
Hull, Lawrence M.
1982-01-01T23:59:59.000Z
Dispersed flow film boiling consists of a dispersion of droplets which are carried over a very hot surface by their vapor. This process occurs in cryogenic equipment and wet steam turbines. It is also of interest in the ...
Dryout droplet distribution and dispersed flow film boiling
Hill, Wayne S.
1982-01-01T23:59:59.000Z
Dispersed flow film boiling is characterized by liquid-phase droplets entrained in a continuous vapor-phase flow. In a previous work at MIT, a model of dispersed flow heat transfer was developed, called the Local Conditions ...
The effects of surface conditions on boiling characteristics
Lorenz, J. J.
1972-01-01T23:59:59.000Z
A unified model relating surface variables to the nucleate pool boiling characteristics was developed. A simple vapor trapping mechanism was postulated and a geometrical model constructed for idealized conical cavities ...
Forced-convection, dispersed-flow film boiling
Hynek, Scott Josef
1969-01-01T23:59:59.000Z
This report presents the latest results of an investigation of the characteristics of dispersed flow film boiling. Heat transfer data are presented for vertical upflow of nitrogen in an electrically heated tube, 0.4 in. ...
Hydrodynamics, heat transfer and flow boiling instabilities in microchannels
Barber, Jacqueline Claire
2010-01-01T23:59:59.000Z
Boiling in microchannels is a very efficient mode of heat transfer with high heat and mass transfer coefficients achieved. Less pumping power is required for two-phase flows than for single-phase liquid flows to achieve ...
Infrared thermometry study of nanofluid pool boiling phenomena
Gerardi, Craig
Abstract Infrared thermometry was used to obtain first-of-a-kind, time- and space-resolved data for pool boiling phenomena in water-based nanofluids with diamond and silica nanoparticles at low concentration (<0.1 vol.%). ...
Determination of pool boiling Critical Heat Flux enhancement in nanofluids
Truong, Bao H. (Bao Hoai)
2007-01-01T23:59:59.000Z
Nanofluids are engineered colloids composed of nano-size particles dispersed in common fluids such as water or refrigerants. Using an electrically controlled wire heater, pool boiling Critical Heat Flux (CHF) of Alumina ...
Effects of surface parameters on boiling heat transfer phenomena
Truong, Bao H. (Bao Hoai)
2011-01-01T23:59:59.000Z
Nanofluids, engineered colloidal dispersions of nanoparticles in fluid, have been shown to enhance pool and flow boiling CHF. The CHF enhancement was due to nanoparticle deposited on the heater surface, which was verified ...
Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces
Attinger, Daniel
Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces Amy Rachel in revised form 30 October 2012 Accepted 31 October 2012 Keywords: Superhydrophobic Superhydrophilic Biphilic- and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics
Burnout in forced convection nucleate boiling of water
Reynolds John Mitchell
1957-01-01T23:59:59.000Z
Data are presented for burnout in forced coivection nucleate boiling of water at pressures above 500 psia. A dimensionless correlation is devised for. the M.I.T. data which is found to be valid for certain recent data ...
Experimental design for study of nucleate boiling in porous structures
Kelley, Mitchell Joseph
2011-01-01T23:59:59.000Z
The superheat required to initiate nucleate boiling inside porous wicks is not well understood in practice. This thesis reports the design of an experimental setup for investigating the onset of vapor nucleation in sintered ...
Enhancement of flow boiling of subcooled water on transverse ribbed surface
Fujita, Yasunobu; Deguchi, Hironobu
1999-07-01T23:59:59.000Z
The present work deals with enhancement of flow boiling heat transfer using transverse ribs of rectangular cross section attached on a flat heating surface. High flux cooling is envisioned in the field of the leading edge technology such as high power laser applications, advanced metallurgical processes, fusion reactors, integrated circuit chips and so forth. In such advanced cooling devices subcooled boiling of water at high velocity is expected as one of most efficient and convenient means for heat removal exceeding 10{sup 7}W/m{sup 2}. In the present experiment, a sheet of stainless-steel (10mm wide, 0.2mm thick and 80mm in heated length) was flush mounted on one wall of a vertical rectangular channel (a cross-section 20mm x 30 mm) and used as a heating surface by passing a direct current. Transverse-ribs made of plastic plate (0.5mm thick and 30mm in lateral length) were attached at an equal longitudinal spacing on the heating surface. Longitudinal spacing of ribs was varied from 2.5, 5, 10, 20mm to infinity (a flat surface without ribs), and the rib height was 2.5mm and 5.0mm. Experiments were conducted with water at a pressure of 0.12MPa in the range of mass velocity from 500kg/m{sup 2}s to 2,000kg/m{sup 2}s (water velocity from 0.5m/s to 2m/s) and subcooling from 20K to 50K. It was found that the ribbed structure strongly affects heat transfer both in the non-boiling and partial nucleate boiling regimes. Enhancement rate of heat transfer coefficient varied from 5% to 50% in excess compared with that for the flat heating plate. According to visual observation of boiling bubbles the circulating flow occurred in a space between each consecutive ribs and seemed to enhance heat transfer. For narrow rib spacing a large coalesced bubble filled up each rib space and impeded the exchange of vapor with liquid, leading to heat transfer deterioration. In the present experimental range of the ribs, a 50% increase of heat transfer coefficient was attained on the ribbed surface with 5mm height and a spacing of 10mm.
Oak, H.D.; Holter, G.M.; Kennedy, W.E. Jr.; Konzek, G.J.
1980-06-01T23:59:59.000Z
Technology, safety and cost information is given for the conceptual decommissioning of a large (1100MWe) boiling water reactor (BWR) power station. Three approaches to decommissioning, immediate dismantlement, safe storage with deferred dismantlement and entombment, were studied to obtain comparisons between costs, occupational radiation doses, potential dose to the public and other safety impacts. It also shows the sensitivity of decommissioning safety and costs to the power rating of a BWR in the range of 200 to 1100 MWe.
Verified integrity properties for safe approximate program transformations
Kim, Deokhwan
Approximate computations (for example, video, audio, and image processing, machine learning, and many scientific computations) have the freedom to generate a range of acceptable results. Approximate program transformations ...
Design, fabrication, packaging and testing of thin film thermocouples for boiling studies
Sinha, Nipun
2009-06-02T23:59:59.000Z
Boiling is the most efficient form of heat transfer. Thermo-fluidic transport mechanisms at different length and time scales govern the nature of boiling. This study was conducted to enhance the understanding of the surface temperature variations...
Mechanism and behavior of nucleate boiling heat transfer to the alkalai liquid metals
Deane, Charles William
1969-01-01T23:59:59.000Z
A model of boiling heat transfer to the alkali liquid metals is postulated from an examination of the events and phases of the nucleate boiling cycle. The model includes the important effect of microlayer evaporation which ...
Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters
Bergles A. E.
1962-01-01T23:59:59.000Z
A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...
Alumina Nanoparticle Pre-coated Tubing Ehancing Subcooled Flow Boiling Cricital Heat Flux
Truong, Bao H.
Nanofluids are engineered colloidal dispersions of nano-sized particle in common base fluids. Previous pool boiling studies have shown that nanofluids can improve critical heat flux (CHF) up to 200% for pool boiling and ...
Acoustic emission feedback control for control of boiling in a microwave oven
White, Terry L. (Oak Ridge, TN)
1991-01-01T23:59:59.000Z
An acoustic emission based feedback system for controlling the boiling level of a liquid medium in a microwave oven is provided. The acoustic emissions from the medium correlated with surface boiling is used to generate a feedback control signal proportional to the level of boiling of the medium. This signal is applied to a power controller to automatically and continuoulsly vary the power applied to the oven to control the boiling at a selected level.
NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING
Maruyama, Shigeo
1 NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING Ying He, Masahiro role in nucleate and transition boiling heat transfer at high heat flux. Many experiments have been in the numerical simulation of boiling heat transfer. In this study, based on the macrolayer evaporation model
ECI International Conference on Boiling Heat Transfer Florianpolis-SC-Brazil, 3-7 May 2009
Yanikoglu, Berrin
. Recently the study of heat transfer in micro pin fin heat sinks has been extended to flow boiling by Koar and Peles (2006c), who studied boiling heat transfer in a hydrofoil-based micro pin fin heat sinkECI International Conference on Boiling Heat Transfer Florianópolis-SC-Brazil, 3-7 May 2009
Flow Boiling Heat Transfer Coefficient In Minichannels Correlation and Trends Satish G. Kandlikar
Kandlikar, Satish
Flow Boiling Heat Transfer Coefficient In Minichannels Correlation and Trends Satish G. Kandlikar York 14623, USA The flow boiling heat transfer in small diameter passages is being applied in many boiling heat transfer coefficient with the correlations developed for conventional channels. It is found
Numerical study of high heat ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b
Maruyama, Shigeo
Numerical study of high heat Żux pool boiling heat transfer Ying He a,*, Masahiro Shoji b , Shigeo simulation model of boiling heat transfer is proposed based on a numerical macrolayer model [S. Maruyama, M. Shoji, S. Shimizu, A numerical simulation of transition boiling heat transfer, in: Proceedings
Boiling water reactor control rod programming using heuristic and mathematical methods
Hayase, T.; Motoda, H.
1980-04-01T23:59:59.000Z
OPROD, a computer code for automatic generation of control rod programming that has successfully been applied to an older boiling water reactor (BWR), has experienced some difficulties when applied to a BWR of larger power density and stronger heterogeneity. To improve the performance, a heuristic algorithm that is derived from accumulated experience has been introduced to search for a feasible rod pattern that satisfies all constraints. Application of this algorithm to an initial cycle of an 800-MW(e) BWR of high heterogeneity has been very successful. It has been demonstrated that the proposed algorithm is capable of finding a feasible rod pattern, even starting from an all-rods-out pattern. Some improvement was also made in the method of approximation programming (MAP) algorithm. The temporal constraint relaxation method is shown to be effective in finding an optimal control rod pattern in MAP starting from a guess pattern that is not feasible.
LIQUID PROPANE GAS (LPG) STORAGE AREA BOILING LIQUID EXPANDING VAPOR EXPLOSION (BLEVE) ANALYSIS
PACE, M.E.
2004-01-13T23:59:59.000Z
The PHA and the FHAs for the SWOC MDSA (HNF-14741) identified multiple accident scenarios in which vehicles powered by flammable gases (e.g., propane), or combustible or flammable liquids (e.g., gasoline, LPG) are involved in accidents that result in an unconfined vapor cloud explosion (UVCE) or in a boiling liquid expanding vapor explosion (BLEVE), respectively. These accident scenarios are binned in the Bridge document as FIR-9 scenarios. They are postulated to occur in any of the MDSA facilities. The LPG storage area will be in the southeast corner of CWC that is relatively remote from store distaged MAR. The location is approximately 30 feet south of MO-289 and 250 feet east of 2401-W by CWC Gate 10 in a large staging area for unused pallets and equipment.
Enhancement of Pool Boiling Heat Transfer in Confined Space
Hsu, Chia-Hsiang
2014-05-05T23:59:59.000Z
on pool boiling. In the study, confinement was achieved by placing a flat plate over heated surface. The flat plate has a hole in the middle, and there is a gap between the flat plate and the heater. The diameters of hole are 2 mm, 3 mm, and 4 mm; the gap...
Jet Flows Around Microbubbles In Subcooled Boiling , Xiaofeng Pengb
Kihm, IconKenneth David
Jet Flows Around Microbubbles In Subcooled Boiling Hao Wanga , Xiaofeng Pengb , David M Strong jet flows were observed emanating from micro bubbles on a 100 µm diameter wire during subcooled analysis. The bubble-top jet flows were characterized by a single jet at the bubble top. Both experiments
Fast Approximate Convex Decomposition
Ghosh, Mukulika
2012-10-19T23:59:59.000Z
Approximate convex decomposition (ACD) is a technique that partitions an input object into "approximately convex" components. Decomposition into approximately convex pieces is both more efficient to compute than exact ...
Approximate Maximum Principle for Discrete Approximations of ...
2012-03-20T23:59:59.000Z
Approximations of Optimal Control Systems with. Nonsmooth .... of any endpoint constraints on trajectories of linear one-dimensional control systems in (PN ).
Kandlikar, Satish
. (2004) developed three- zone flow boiling heat transfer model to describe evaporation of elongated
Knowledge and abilities catalog for nuclear power plant operators: boiling water reactors
Not Available
1986-09-01T23:59:59.000Z
The Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Boiling-Water Reactors (BWR) (NUREG-1123) provides the basis for the development of content-valid licensing examinations for reactor operators (ROs) and senior reactor operators (SROs). The examinations developed using the BWR Catalog and Examiners' Handbook for Developing Operator Licensing Examinations (NUREG-1121) will cover those topics listed under Title 10, Code of Federal Regulations, Part 55. The BWR Catalog contains approximately 7000 knowledge and ability (K/A) statements for ROs and SROs at boiling water reactors. Each K/A statement has been rated for its importance to the safe operation of the plant in a manner ensuring personnel and public health and safety. The BWR K/A Catalog is organized into five major sections: Plant-wide Generic Knowledge and Ability Statements, Plant Systems grouped by Safety Function, Emergency and Abnormal Plant Evolutions, Components, and Theory. The BWR Catalog represents a modification of the form and content of the K/A Catalog for Nuclear Power Plant Operators: Pressurized Water Reactors (NUREG-1122). First, categories of knowledge and ability statements have been redefined. Second, the scope of the definition of emergency and abnormal plant evolutions has been revised in line with a symptom-based approach. Third, K/As related to the operational applications of theory have been incorporated into the delineations for both plant systems and emergency and abnormal plant evolutions, while K/As pertaining to theory fundamental to plant operation have been delineated in a separate theory section. Finally, the components section has been revised.
NONE
1995-08-01T23:59:59.000Z
The Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Boiling-Water Reactors (BWRs) (NUREG-1123, Revision 1) provides the basis for the development of content-valid licensing examinations for reactor operators (ROs) and senior reactor operators (SROs). The examinations developed using the BWR Catalog along with the Operator Licensing Examiner Standards (NUREG-1021) and the Examiner`s Handbook for Developing Operator Licensing Written Examinations (NUREG/BR-0122), will cover the topics listed under Title 10, Code of Federal Regulations, Part 55 (10 CFR 55). The BWR Catalog contains approximately 7,000 knowledge and ability (K/A) statements for ROs and SROs at BWRs. The catalog is organized into six major sections: Organization of the Catalog, Generic Knowledge and Ability Statements, Plant Systems grouped by Safety Functions, Emergency and Abnormal Plant Evolutions, Components, and Theory. Revision 1 to the BWR Catalog represents a modification in form and content of the original catalog. The K/As were linked to their applicable 10 CFR 55 item numbers. SRO level K/As were identified by 10 CFR 55.43 item numbers. The plant-wide generic and system generic K/As were combined in one section with approximately one hundred new K/As. Component Cooling Water and Instrument Air Systems were added to the Systems Section. Finally, High Containment Hydrogen Concentration and Plant Fire On Site evolutions added to the Emergency and Abnormal Plant Evolutions section.
Thermal stability of a spherical shell heated by convection and cooled by boiling
Qaim-Maqami, Hassan
1973-01-01T23:59:59.000Z
such high heat transfer rates by forced convection would require extremely high veloc- ities with subsequent high pressure dropsy With nuclee, boiling, however, such high heat transfe. rates an be obtained at much smaller velocities. Boiling heat...THERMAL STABILITY OF A. SPHERICAL SHELL HEATED BY CONVECTION AND COOLED BY BOILING A Thesis HASSAN @AIM-MAQAMI Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER...
Oak, H.D.; Holter, G.M.; Kennedy, W.E. Jr.; Konzek, G.J.
1980-06-01T23:59:59.000Z
Technology, safety and cost information is given for the conceptual decommissioning of a large (1100MWe) boiling water reactor (BWR) power station. Three approaches to decommissioning, immediate dismantlement, safe storage with deferred dismantlement and entombment, were studied to obtain comparisons between costs, occupational radiation doses, potential dose to the public and other safety impacts. It also shows the sensitivity of decommissioning safety and costs to the power rating of a BWR in the range of 200 to 1100 MWE.
Great Boiling Springs Geothermal Area | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdfGetec AG Contracting JumpGoveNebraska: EnergyGratingsGreat BasinGreat Boiling
Efficient Cooling in Engines with Nucleate Boiling | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny:RevisedAdvisory BoardNucleate Boiling Efficient Cooling in Engines with Nucleate
Efficient Cooling in Engines with Nucleated Boiling | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny:RevisedAdvisory BoardNucleate Boiling Efficient Cooling in Engines with
Approximation of Stochastic Process
Alois Pichler
2012-05-08T23:59:59.000Z
May 8, 2012 ... The approximation of stochastic processes by trees is an important topic in ... process ? is replaced by a finitely valued stochastic scenario ...
Water inventory management in condenser pool of boiling water reactor
Gluntz, Douglas M. (San Jose, CA)
1996-01-01T23:59:59.000Z
An improved system for managing the water inventory in the condenser pool of a boiling water reactor has means for raising the level of the upper surface of the condenser pool water without adding water to the isolation pool. A tank filled with water is installed in a chamber of the condenser pool. The water-filled tank contains one or more holes or openings at its lowermost periphery and is connected via piping and a passive-type valve (e.g., squib valve) to a high-pressure gas-charged pneumatic tank of appropriate volume. The valve is normally closed, but can be opened at an appropriate time following a loss-of-coolant accident. When the valve opens, high-pressure gas inside the pneumatic tank is released to flow passively through the piping to pressurize the interior of the water-filled tank. In so doing, the initial water contents of the tank are expelled through the openings, causing the water level in the condenser pool to rise. This increases the volume of water available to be boiled off by heat conducted from the passive containment cooling heat exchangers. 4 figs.
Boiling water neutronic reactor incorporating a process inherent safety design
Forsberg, Charles W. (Kingston, TN)
1987-01-01T23:59:59.000Z
A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (non-borated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.
Boiling water neutronic reactor incorporating a process inherent safety design
Forsberg, C.W.
1985-02-19T23:59:59.000Z
A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (nonborated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two water volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.
Water inventory management in condenser pool of boiling water reactor
Gluntz, D.M.
1996-03-12T23:59:59.000Z
An improved system for managing the water inventory in the condenser pool of a boiling water reactor has means for raising the level of the upper surface of the condenser pool water without adding water to the isolation pool. A tank filled with water is installed in a chamber of the condenser pool. The water-filled tank contains one or more holes or openings at its lowermost periphery and is connected via piping and a passive-type valve (e.g., squib valve) to a high-pressure gas-charged pneumatic tank of appropriate volume. The valve is normally closed, but can be opened at an appropriate time following a loss-of-coolant accident. When the valve opens, high-pressure gas inside the pneumatic tank is released to flow passively through the piping to pressurize the interior of the water-filled tank. In so doing, the initial water contents of the tank are expelled through the openings, causing the water level in the condenser pool to rise. This increases the volume of water available to be boiled off by heat conducted from the passive containment cooling heat exchangers. 4 figs.
Demazičre, Christophe
Comparison of thorium-based fuels with different fissile components in existing boiling water, SE-412 96 Göteborg, Sweden Keywords: Thorium BWR Neutronics a b s t r a c t With the aim of investigating the technical feasibility of fuelling a conventional BWR (Boiling Water Reactor) with thorium
INVESTIGATING THE EFFECT OF HEATING METHOD ON POOL BOILING HEAT TRANSFER
Kandlikar, Satish
INVESTIGATING THE EFFECT OF HEATING METHOD ON POOL BOILING HEAT TRANSFER Satish G. Kandlikar Department Rochester Institute of Technology Rochester, NY, USA Phone: (716) 475-6728; Fax: (716) 475-7710 E-mail: SGKEME@RIT.EDU ABSTRACT Pool boiling experiments are generally conducted with electrically heated
Effect of surface conditions on boiling heat transfer of refrigerants in shell-and-tube evaporators
Danilova, G.N.; Dyundin, V.A.; Borishanskaya, A.V.; Soloviyov, A.G.; Vol'nykh, Y.A.; Kozyrev, A.A.
1990-01-01T23:59:59.000Z
Experimental results are presented for the boiling heat transfer performance of R 22 and R 717 on surfaces with porous metallized coatings. A calculational-theoretical model is given for predicting the heat transfer of refrigerants boiling on a bundle of finned tubes.
Boiling heat transfer in a hydrofoil-based micro pin fin heat sink
Peles, Yoav
transfer in a horizontal tube bundle and reported an increase in local heat transfer coefficient boiling heat transfer of water in small horizontal tube bundles at low velocities. How- ever, the dataBoiling heat transfer in a hydrofoil-based micro pin fin heat sink Ali Kosßar, Yoav Peles
Boiling Crisis as a Non-Equilibrium Drying V. S. Nikolayev, D. A. Beysens, J. Hegseth
Nikolayev, Vadim S.
crisis is the formation of a vapor film between the heater and the liquid when the heat supply exceeds in the coordinates heat supply heater temperature is sketched in Fig. 1 for the case of stationary boiling experiment, the so called "pool boiling". When the heat supply to the fluid pool is small, only a fluid
A Review Of Recent Progress On Nano/micro Scale Nucleate Boiling Fundamentals
Chung, J. N.
2011-01-01T23:59:59.000Z
Recent research progress in the area of nano/micro scale nucleate boiling is reviewed and an up-to-date summary is provided with a focus on the advances of fundamental boiling physics. This review examines nano/micro scale ...
Glenn, Stephen T.
2011-08-08T23:59:59.000Z
The effects of a carbon nanotube (CNT) coating on bubble departure diameter and frequency in pool boiling experiments was investigated and compared to those on a bare silicon wafer. The pool boiling experiments were performed at liquid subcooling...
Glenn, Stephen T.
2011-08-08T23:59:59.000Z
The effects of a carbon nanotube (CNT) coating on bubble departure diameter and frequency in pool boiling experiments was investigated and compared to those on a bare silicon wafer. The pool boiling experiments were performed at liquid subcooling...
Rod bundle film boiling and steam cooling data base and correlation evaluation
Yoder, G.L.
1986-08-01T23:59:59.000Z
Film boiling and steam cooling data from several rod bundle experiments have been compiled from fourteen references. Steam cooling data are presented for five references, while film boiling data are presented for ten references (two of these for tube geometry). The compilation includes experimental parameters necessary for characterization of the local rod heat transfer. These data have been compared to several commonly used film boiling and pure vapor heat transfer coefficients. Results show that the Dougall-Rohsenow correlation tends to overpredict film boiling heat transfer, while Condie-Bengston IV and the Groeneveld 5. series correlations do a reasonable job of predicting film boiling heat fluxes. Of the three vapor correlations examined, the Dittus-Boelter correlation is least conservative, and the Sozer correlation most conservative.
Ammerman, C.N.; You, S.M.; Hong, Y.S. [Univ. of Texas, Arlington, TX (United States). Dept. of Mechanical and Aerospace Engineering
1995-12-31T23:59:59.000Z
A recently developed photographic method is used to quantify vapor volumetric flow rate above a boiling wire. The volumetric flow rate is combined with additional analyses to determine the overall contributions to the total heat flux from four nucleate boiling heat transfer mechanisms (latent heat, natural convection, Marangoni flow, and micro-convection). This technique is used to quantify the boiling heat transfer mechanisms versus heat flux for a 510-{micro}m wire immersed in saturated water and in water with a small amount of liquid soap added. These data are compared with similar data taken for a 75-{micro}m wire boiling in saturated FC-72. For all cases, latent heat is the dominant heat transfer mechanism in the fully developed nucleate boiling regime. In addition, the latent heat component is significantly increased by the addition of small amounts of soap (surfactant).
Determination of the boiling enhancement mechanism caused by surfactant addition to water
Ammerman, C.N.; You, S.M. [Univ. of Texas, Arlington, TX (United States). Dept. of Mechanical and Aerospace Engineering
1995-12-31T23:59:59.000Z
In the present investigation, boiling heat transfer coefficients are measured for an electrically heated 390-{micro}m, platinum wire immersed in saturated water, and in water mixed with three different concentrations of sodium dodecyl sulfate (an anionic surfactant). The addition of a surfactant to water is known to enhance boiling heat transfer. A recently developed photographic/laser Doppler anemometry measurement technique is used to quantify the vapor volumetric flowrate departing from the wire during the boiling process. The volumetric flowrate data are combined with results from additional analyses to determine the overall contributions to the total heat flux from three nucleate boiling heat transfer mechanisms. Comparisons are made to determine which heat transfer mechanisms are affected by the surfactant addition, and thus, which mechanisms promote boiling enhancement.
Metallurgical failure analysis of a propane tank boiling liquid expanding vapor explosion (BLEVE).
Kilgo, Alice C.; Eckelmeyer, Kenneth Hall; Susan, Donald Francis
2005-01-01T23:59:59.000Z
A severe fire and explosion occurred at a propane storage yard in Truth or Consequences, N.M., when a truck ran into the pumping and plumbing system beneath a large propane tank. The storage tank emptied when the liquid-phase excess flow valve tore out of the tank. The ensuing fire engulfed several propane delivery trucks, causing one of them to explode. A series of elevated-temperature stress-rupture tears developed along the top of a 9800 L (2600 gal) truck-mounted tank as it was heated by the fire. Unstable fracture then occurred suddenly along the length of the tank and around both end caps, along the girth welds connecting the end caps to the center portion of the tank. The remaining contents of the tank were suddenly released, aerosolized, and combusted, creating a powerful boiling liquid expanding vapor explosion (BLEVE). Based on metallography of the tank pieces, the approximate tank temperature at the onset of the BLEVE was determined. Metallurgical analysis of the ruptured tank also permitted several hypotheses regarding BLEVE mechanisms to be evaluated. Suggestions are made for additional work that could provide improved predictive capabilities regarding BLEVEs and for methods to decrease the susceptibility of propane tanks to BLEVEs.
Feasibility study on the thorium fueled boiling water breeder reactor
PetrusTakaki, N. [Dept. of Applied Science, Tokai Univ., Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)
2012-07-01T23:59:59.000Z
The feasibility of (Th,U)O 2 fueled, boiling water breeder reactor based on conventional BWR technology has been studied. In order to determine the potential use of water cooled thorium reactor as a competitive breeder, this study evaluated criticality, breeding and void reactivity coefficient in response to changes made in MFR and fissile enrichments. The result of the study shows that while using light water as moderator, low moderator to fuel volume ratio (MFR=0.5), it was possible to breed fissile fuel in negative void reactivity condition. However the burnup value was lower than the value of the current LWR. On the other hand, heavy water cooled reactor shows relatively wider feasible breeding region, which lead into possibility of designing a core having better neutronic and economic performance than light water with negative void reactivity coefficient. (authors)
Boiling Heat Transfer on Superhydrophilic, Superhydrophobic, and Superbiphilic Surfaces
Betz, Amy Rachel; Kim, Chang-Jin 'CJ'; Attinger, Daniel
2012-01-01T23:59:59.000Z
With recent advances in micro- and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics of fluids on these surfaces have been well characterized. However, few investigations have been made into the potential of these surfaces to control and enhance other transport phenomena. In this article, we characterize pool boiling on surfaces with wettabilities varied from superhydrophobic to superhydrophilic, and provide nucleation measurements. The most interesting result of our measurements is that the largest heat transfer coefficients are reached not on surfaces with spatially uniform wettability, but on biphilic surfaces, which juxtapose hydrophilic and hydrophobic regions. We develop an analytical model that describes how biphilic surfaces effectively manage the vapor and liquid transport, delaying critical heat flux and maximizing the heat transfer coefficient. Finally, we manufacture and test the first superbiphilic surfaces (juxtaposing superhydrophobic ...
Nucleate boiling pressure drop in an annulus: Book 8
Not Available
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of tables of temperature measurements.
Nucleate boiling pressure drop in an annulus: Book 6
Not Available
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of a summary of temperature measurements to include recorded minima, maxima, averages and standard deviations.
Nucleate boiling pressure drop in an annulus: Book 7
Not Available
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists solely of tables of temperature measurements; minima, maxima, averages and standard deviations being measured.
Nucleate boiling pressure drop in an annulus: Book 4
Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.
Nucleate boiling pressure drop in an annulus: Book 3
Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.
Nucleate boiling pressure drop in an annulus: Book 2
Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.
1992-11-01T23:59:59.000Z
The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. Nineteen test series and a total of 178 tests were performed. Testing addressed the effects of: Heat flux; pressure; helium gas; power tilt; ribs; asymmetric heat flux.
Transient queueing approximations for computer networks
Baker, William A.
1986-01-01T23:59:59.000Z
for just the mean. Rothkopf/Oren's and Chang/Wang's methods obtained mean and variance values, and Clark's method produced several quantities which were used to find mean and variance statistics. For the M/M/1 case, the approximations by Gark and Chang... were very ac- curate over a wide range of input patterns and initial conditions. Rothkopf's was accurate over sll conditions but never as accurate as Chang or Clark. Johnston's and Rider's approximations performed acceptably only over some...
Identification of pool boiling heat transfer mechanisms in FC-72 using a single-photo method
Ammerman, C.N.; You, S.M.; Hong, Y.S. [Univ. of Texas, Arlington, TX (United States). Dept. of Mechanical and Aerospace Engineering
1995-10-01T23:59:59.000Z
A unique method to determine the vapor flow rate above a boiling cylinder utilizing a single photograph is developed and discussed. This method is applied to a 75-{micro}m wire immersed in a saturated, highly wetting liquid (FC-72) to determine bubble departure diameter, frequency, and nucleation site density. Using the experimental results, an analysis is performed to evaluate individual heat flux contributions of the four pool boiling mechanisms: latent heat, natural convection, Marangoni flow, and micro-convection. Latent heat is identified as the dominant mechanism throughout most of the nucleate boiling regime.
CORQUENCH: A model for gas sparging-enhanced melt-water, film boiling heat transfer
Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.
1990-01-01T23:59:59.000Z
A phenomenological model (CORQUENCH) has been developed to describe the gas-sparging enhanced film boiling heat transfer between a molten pool of corium and an overlying water layer. The model accounts for thermal radiation across the vapor film, bulk liquid subcooling, interfacial area enhancement due to sparging gas, and melt entrainment into the overlying water layer. In this paper, the modeling approach is described, and a comparison with the lead-Freon 11 and lead-water film boiling experiment data of Greene is made. Predictions are then made for the case of film boiling over corium in the presence of sparging concrete decomposition gases. 15 refs., 3 figs.
New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes
Chen, G. F.; Gong, M. Q.; Wu, J. F.; Zou, X. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); Wang, S. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); University of Chinese Academy of Science, No. 19 YuQuan Road, Beijing, 100049 (China)
2014-01-29T23:59:59.000Z
Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction.
Multicriteria approximation through decomposition
Burch, C. [Carnegie Mellon Univ., Pittsburgh, PA (United States). School of Computer Sciences]|[Sandia National Labs., Albuquerque, NM (United States); Krumke, S. [Univ. of Wuerzburg (Germany). Dept. of Computer Science; Marathe, M. [Los Alamos National Lab., NM (United States); Phillips, C. [Sandia National Labs., Albuquerque, NM (United States). Applied Mathematics Dept.; Sundberg, E. [Rutgers Univ., NJ (United States). Dept. of Computer Science]|[Sandia National Labs., Albuquerque, NM (United States)
1997-12-01T23:59:59.000Z
The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of the technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. The method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) The authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing. (2) They show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.
Multicriteria approximation through decomposition
Burch, C. [Carnegie Mellon Univ., Pittsburgh, PA (United States). School of Computer Science; Krumke, S. [Univ. of Wuerzburg (Germany). Dept. of Computer Science; Marathe, M. [Los Alamos National Lab., NM (United States); Phillips, C. [Sandia National Labs., Albuquerque, NM (United States). Applied Mathematics Dept.; Sundberg, E. [Rutgers Univ., NJ (United States). Dept. of Computer Science
1998-06-01T23:59:59.000Z
The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of their technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. Their method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) the authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing; (2) they also show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.
Thermal-hydraulic instabilities in pressure tube graphite-moderated boiling water reactors
Tsiklauri, G.; Schmitt, B.
1995-09-01T23:59:59.000Z
Thermally induced two-phase instabilities in non-uniformly heated boiling charmers in RBMK-1000 reactor have been analyzed using RELAP5/MOD3 code. The RELAP5 model of a RBMK-1000 reactor was developed to investigate low flow in a distribution group header (DGH) supplying 44 fuel pressure tubes. The model was evaluated against experimental data. The results of the calculations indicate that the period of oscillation for the high power tube varied from 3.1s to 2.6s, over the power range of 2.0 MW to 3.0 MW, respectively. The amplitude of the flow oscillation for the high powered tube varied from +100% to {minus}150% of the tube average flow. Reverse flow did not occur in the lower power tubes. The amplitude of oscillation in the subcooled region at the inlet to the fuel region is higher than in the saturated region at the outlet. In the upper fuel region and outlet connectors the flow oscillations are dissipated. The threshold of flow instability for the high powered tubes of a RBMK reactor is compared to Japanese data and appears to be in good agreement.
Protective coatings for radiation control in boiling water nuclear power reactors
Rao, T.V.; Vook, R.W.; Meyer, W.; Wittwer, C.
1987-07-01T23:59:59.000Z
Stainless-steel surfaces (316 nuclear grade) develop /sup 60/Co-embedded oxide scales when exposed to a boiling water reactor (BWR) environment. Thin films such as Pd, Ni, Au, and Cr were found to drastically reduce the radioactive buildup. The films were prepared by vacuum evaporation and electroless deposition. The electroless coating consisted of a thin cathodically treated layer, followed by a nickel strike (--1 ..mu..m) and an electroless layer (--600 A). The present paper describes the results obtained from a transmission electron microscope replica study of the radioactive growths that formed on uncoated and thin-film-coated stainless-steel rods. The coated rods, when exposed to a simulated BWR environment, exhibited corrosion film growths ranging from large faceted grains (uncoated) and isolated islands of similar crystallites (Au coated) to extremely small nucleated growths (Pd, Ni coated). Also, it was found that chromium oxide films, which generally form a protective oxide on stainless steel, do not completely stop either the corrosion film growth or the associated radioactive buildup. The morphologies of the corrosion film growth were correlated with the relative /sup 60/Co activity, and the substrate topography. The best coating to date was found to be a Pd thin film, 1000 A thick, which reduced the radioactive buildup by a factor of --13.
Experimental Two-Phase Flow Characterization of Subcooled Boiling in a Rectangular Channel
Estrada Perez, Carlos E.
2010-01-16T23:59:59.000Z
On the efforts to provide a reliable source of experimental information on turbulent subcooled boiling ow, time resolved Particle Tracking Velocimetry (PTV) experiments were carried out using HFE-301 refrigerant ow through a vertical rectangular...
Development of a model to predict flow oscillations in low-flow sodium boiling
Levin, Alan Edward
1980-01-01T23:59:59.000Z
An experimental and analytical program has been carried out in order to better understand the cause and effect of flow oscillations in boiling sodium systems. These oscillations have been noted in previous experiments with ...
Bubble behavior in subcooled flow boiling on surfaces of variable wettability
Tow, Emily W
2012-01-01T23:59:59.000Z
Flow boiling is important in energy conversion and thermal management due to its potential for very high heat fluxes. By improving understanding of the conditions leading to bubble departure, surfaces can be designed that ...
Stability analysis of the boiling water reactor : methods and advanced designs
Hu, Rui, Ph. D. Massachusetts Institute of Technology
2010-01-01T23:59:59.000Z
Density Wave Oscillations (DWOs) are known to be possible when a coolant undergoes considerable density reduction while passing through a heated channel. In the development of boiling water reactors (BWRs), there has been ...
Visualization of flow boiling in an annular heat exchanger under reduced gravity conditions
Westheimer, David Thomas
2000-01-01T23:59:59.000Z
This work examines the effects of gravitational acceleration on the flow boiling process. A test facility focusing on an annular heat exchanger was designed, built out of borosilicate glass, and flown on NASA's KC-135 reduced gravity airplane...
A visualization comparison of convective flow boiling heat transfer augmentation devices
Lundy, Brian Franklin
1998-01-01T23:59:59.000Z
The qualitative effects of inset-table heat transfer phics. augmentation devices on vertical in-tube convective flow boiling flow regimes, transition mechanisms, and heat transfer are presented in this study. Three twisted tapes with twist ratios...
Di, Yuan 1988-
2012-12-05T23:59:59.000Z
This present study seeks to contribute detailed visualization data on a pool boiling experiments using HFE-7000. Particle Image Velocimetry (PIV) was used to measure the time resolved whole field liquid velocity. Bubble dynamic parameters...
Sathyamurthi, Vijaykumar
2011-02-22T23:59:59.000Z
of subcooling and micro/nano-scale surface texturing using MWCNT coatings on the dynamics of pool boiling is assessed. Dynamic invariants such as correlation dimensions and Lyapunov spectrum are evaluated for the reconstructed attractor. A non-linear noise...
Conceptual design of an annular-fueled superheat boiling water reactor
Ko, Yu-Chih, Ph. D. Massachusetts Institute of Technology
2011-01-01T23:59:59.000Z
The conceptual design of an annular-fueled superheat boiling water reactor (ASBWR) is outlined. The proposed design, ASBWR, combines the boiler and superheater regions into one fuel assembly. This ensures good neutron ...
Prediction of departure from nucleate boiling in PWR fast power transients
Lenci, Giancarlo
2013-01-01T23:59:59.000Z
An assessment is conducted of the differences in predicted results between use of steady state versus transient Departure from Nucleate Boiling (DNB) models, for fast power transients under forced convective heat exchange ...
A study of system-induced instabilities in forced-convection flows with subcooled boiling
Maulbetsch, John S.
1965-01-01T23:59:59.000Z
A combined analytical and experimental program was carried out to investigate the problem of hydrodynamic stability of forcedconvection flows with boiling. The study was restricted to the flow of water in small channels ...
Thermal non-equilibrium in dispersed flow film boiling in a vertical tube
Forslund, Robert Paul
1966-01-01T23:59:59.000Z
The departure from thermal equilibrium between a dispersed liquid phase and its vapor at high quality during film boiling is investigated, The departure from equilibruim is manifested by the high resistance to heat transfer ...
Sathyamurthi, Vijaykumar
2011-02-22T23:59:59.000Z
The objective of this investigation is to measure and analyze surface temperature fluctuations in pool boiling. The surface temperature fluctuations were recorded on silicon surfaces with and without multi-walled carbon nanotubes (MWCNT). Novel Thin...
Nano-engineering the boiling surface for optimal heat transfer rate and critical heat flux
Phillips, Bren Andrew
2011-01-01T23:59:59.000Z
The effects on pool boiling characteristics such as critical heat flux and the heat transfer coefficient of different surface characteristics such as surface wettability, roughness, morphology, and porosity are not well ...
Camera Inspection Arm for Boiling Water Reactors - 13330
Martin, Scott; Rood, Marc [S.A. Technology, 3985 S. Lincoln Ave, Loveland, CO 80537 (United States)] [S.A. Technology, 3985 S. Lincoln Ave, Loveland, CO 80537 (United States)
2013-07-01T23:59:59.000Z
Boiling Water Reactor (BWR) outage maintenance tasks can be time-consuming and hazardous. Reactor facilities are continuously looking for quicker, safer, and more effective methods of performing routine inspection during these outages. In 2011, S.A. Technology (SAT) was approached by Energy Northwest to provide a remote system capable of increasing efficiencies related to Reactor Pressure Vessel (RPV) internal inspection activities. The specific intent of the system discussed was to inspect recirculation jet pumps in a manner that did not require manual tooling, and could be performed independently of other ongoing inspection activities. In 2012, SAT developed a compact, remote, camera inspection arm to create a safer, more efficient outage environment. This arm incorporates a compact and lightweight design along with the innovative use of bi-stable composite tubes to provide a six-degree of freedom inspection tool capable of reducing dose uptake, reducing crew size, and reducing the overall critical path for jet pump inspections. The prototype camera inspection arm unit is scheduled for final testing in early 2013 in preparation for the Columbia Generating Station refueling outage in the spring of 2013. (authors)
Multi-cycle boiling water reactor fuel cycle optimization
Ottinger, K.; Maldonado, G.I. [University of Tennessee, 311 Pasqua Engineering Building, Knoxville, TN 37996-2300 (United States)
2013-07-01T23:59:59.000Z
In this work a new computer code, BWROPT (Boiling Water Reactor Optimization), is presented. BWROPT uses the Parallel Simulated Annealing (PSA) algorithm to solve the out-of-core optimization problem coupled with an in-core optimization that determines the optimum fuel loading pattern. However it uses a Haling power profile for the depletion instead of optimizing the operating strategy. The result of this optimization is the optimum new fuel inventory and the core loading pattern for the first cycle considered in the optimization. Several changes were made to the optimization algorithm with respect to other nuclear fuel cycle optimization codes that use PSA. Instead of using constant sampling probabilities for the solution perturbation types throughout the optimization as is usually done in PSA optimizations the sampling probabilities are varied to get a better solution and/or decrease runtime. The new fuel types available for use can be sorted into an array based on any number of parameters so that each parameter can be incremented or decremented, which allows for more precise fuel type selection compared to random sampling. Also, the results are sorted by the new fuel inventory of the first cycle for ease of comparing alternative solutions. (authors)
Generic risk insights for General Electric boiling water reactors
Travis, R.; Taylor, J. (Brookhaven National Lab., Upton, NY (USA)); Chung, J. (Nuclear Regulatory Commission, Washington, DC (USA). Office of Nuclear Reactor Regulation)
1991-05-01T23:59:59.000Z
A methodology has been developed to extract generic risk-based information from probabilistic risk assessments (PRAs) of General Electric boiling water rectors and applying the insights gained to plants that have not been subjected to a PRA. The available risk assessments (six plants) were examined to identify the most probable, i.e., dominant accident sequences at each plants. The goal was to include all sequences which represented at least 80% of core damage frequency. If the same plant specific dominant accident sequence appeared within this boundary in at least two plant PRAs, the sequence was considered to be a representative sequence. Eight sequences met this definition. From these sequences, the most important component failures and human error that contributed to each sequence have been prioritized. Guidance is provided to prioritize the representative sequences and modify selected basic events that have been shown to be sensitive to the plant specific design or operating variations of the contributing PRAs. This risk-based guidance can be used for utility and NRC activities including operator training, maintenance, design review, and inspections. 13 refs., 6 tabs.
Aging study of boiling water reactor high pressure injection systems
Conley, D.A.; Edson, J.L.; Fineman, C.F. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)
1995-03-01T23:59:59.000Z
The purpose of high pressure injection systems is to maintain an adequate coolant level in reactor pressure vessels, so that the fuel cladding temperature does not exceed 1,200{degrees}C (2,200{degrees}F), and to permit plant shutdown during a variety of design basis loss-of-coolant accidents. This report presents the results of a study on aging performed for high pressure injection systems of boiling water reactor plants in the United States. The purpose of the study was to identify and evaluate the effects of aging and the effectiveness of testing and maintenance in detecting and mitigating aging degradation. Guidelines from the United States Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program were used in performing the aging study. Review and analysis of the failures reported in databases such as Nuclear Power Experience, Licensee Event Reports, and the Nuclear Plant Reliability Data System, along with plant-specific maintenance records databases, are included in this report to provide the information required to identify aging stressors, failure modes, and failure causes. Several probabilistic risk assessments were reviewed to identify risk-significant components in high pressure injection systems. Testing, maintenance, specific safety issues, and codes and standards are also discussed.
Oak, H.D.; Holter, G.M.; Kennedy, W.E. Jr.; Konzek, G.J.
1980-06-01T23:59:59.000Z
Technology, safety and cost information is given for the conceptual decommissioning of a large (1100MWe) boiling water reactor (BWR) power station. Three approaches to decommissioning, immediate dismantlement, safe storage with deferred dismantlement and entombment, were studied to obtain comparisons between costs, occupational radiation doses, potential dose to the public and other safety impacts. It also shows the sensitivity of decommissioning safety and costs to the power rating of a BWR in the range of 200 to 1100 MWE. This volume contains the appendices.
Boiling behavior of sodium-potassium alloy in a bench-scale solar receiver
Moreno, J.B.; Andraka, C.E.; Moss, T.A.
1992-01-01T23:59:59.000Z
During 1989-90, a 75-kW{sub t} sodium reflux pool-boiler solar receiver was successfully demonstrated at Sandia National Laboratories. Significant features of this receiver include (1) boiling sodium as the heat transfer medium and (2) electric-discharge-machined (EDM) cavities as artificial nucleation sites to stabilize boiling. Since this first demonstration, design of a second-generation pool-boiler receiver that will bring the concept closer to commercialization has begun. For long life, the new receiver uses Haynes Alloy 230. For increased safety factors against film boiling and flooding, it has a refined shape and somewhat larger dimensions. To eliminate the need for trace heating, the receiver will boil the sodium-potassium alloy NaK-78 instead of sodium. To reduce manufacturing costs, it will use one of a number of alternatives to EDM cavities for stabilization of boiling. To control incipient-boiling superheats, especially during hot restarts, it will contain a small amount of inert gas. Before the new receiver design could be finalized, bench-scale tests of some of the proposed changes were necessary. A series of bench-scale pool boilers were built from Haynes Alloy 230 and filled with NaK-78. Various boiling-stabilizer candidates were incorporated into them, including laser-drilled cavities and a number of different sintered-powder-metal coatings. These bench-scale pool boilers have been operated at temperatures up to 750{degree}C, heated by quartz lamps with incident radiant fluxes up to 95 W/cm{sup 2}. The effects of various orientations and added gases have been studied. results of these studies are presented. 15 refs.
Film boiling on spheres in single- and two-phase flows.
Liu, C.; Theofanous, T. G.
2000-08-29T23:59:59.000Z
Film boiling on spheres in single- and two-phase flows was studied experimentally and theoretically with an emphasis on establishing the film boiling heat transfer closure law, which is useful in the analysis of nuclear reactor core melt accidents. Systematic experimentation of film boiling on spheres in single-phase water flows was carried out to investigate the effects of liquid subcooling (from 0 to 40 C), liquid velocity (from 0 to 2 m/s), sphere superheat (from 200 to 900 C), sphere diameter (from 6 to 19 mm), and sphere material (stainless steel and brass) on film boiling heat transfer. Based on the experimental data a general film boiling heat transfer correlation is developed. Utilizing a two-phase laminar boundary-layer model for the unseparated front film region and a turbulent eddy model for the separated rear region, a theoretical model was developed to predict the film boiling heat transfer in all single-phase regimes. The film boiling from a sphere in two-phase flows was investigated both in upward two-phase flows (with void fraction from 0.2 to 0.65, water velocity from 0.6 to 3.2 m/s, and steam velocity from 3.0 to 9.0 m/s) and in downward two-phase flows (with void fraction from 0.7 to 0.95, water velocity from 1.9 to 6.5 m/s, and steam velocity from 1.1 to 9.0 m/s). The saturated single-phase heat transfer correlation was found to be applicable to the two-phase film boiling data by making use of the actual water velocity (water phase velocity), and an adjustment factor of (1 - {alpha}){sup 1/4} (with a being the void fraction) for downward flow case only. Slight adjustments of the Reynolds number exponents in the correlation provided an even better interpretation of the two-phase data. Preliminary experiments were also conducted to address the influences of multi-sphere structure on the film boiling heat transfer in single- and two-phase flows.
Gas bubbling-enhanced film boiling of Freon-11 on liquid metal pools. [PWR; BWR
Greene, G.A.
1985-01-01T23:59:59.000Z
In the analysis of severe core damage accidents in LWRs, a major driving force which must be considered in evaluating containment loading and fission product transport is the ex-vessel interaction between molten core debris and structural concrete. Two computer codes have been developed for this purpose, the CORCON-MOD2 model of ex-vessel, core concrete interactions and the VANESA model for aerosol generation and fission product release as a result of molten core-concrete interactions. Under a wide spectrum of reactor designs and accident sequences, it is possible for water to come into contact with the molten core debris and form a coolant pool overlying the core debris which is attacking the concrete. As the concrete decomposes, noncondensable gases are released, which bubble through the melt and across the boiling interface, affecting the liquid-liquid boiling process. Currently, the CORCON code includes the classical Berenson model for film boiling over a horizontal flat plate for this phenomenon. The objectives of this activity are to investigate the influence of transverse noncondensable gas flux on the magnitude of the stable liquid-liquid film boiling heat flux and develop a gas flux-enhanced, liquid-liquid film boiling model for incorporation into the CORCON-MOD2 computer code to replace or modify the Berenson model.
Heat transfer characteristics of R410A-oil mixture flow boiling inside a 7 mm straight smooth tube
Hu, Haitao; Ding, Guoliang; Wei, Wenjian; Wang, Zhence [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Wang, Kaijian [Fujitsu General Institute of Air-Conditioning Technology Limited, Kawasaki 213-8502 (Japan)
2008-01-15T23:59:59.000Z
Two-phase flow patterns and heat transfer characteristics of R410A-oil mixture flow boiling inside a straight smooth tube with the outside diameter of 7.0 mm were investigated experimentally. The experimental conditions include the evaporation temperature of 5 C, the mass flux from 200 to 400 kg m{sup -2} s{sup -1}, the heat flux from 7.56 to 15.12 kW m{sup -2}, the inlet vapor quality from 0.2 to 0.7, nominal oil concentration from 0% to 5%. The test results show that the heat transfer coefficient of R410A-oil mixture increases with mass flux of refrigerant-oil mixture; the presence of oil enhances the heat transfer at the range of low and intermediate vapor qualities; there is a peak of local heat transfer coefficient at about 2-4% nominal oil concentration at higher vapor qualities, and the peak shifts to lower nominal oil concentration with the increasing of vapor qualities; higher nominal oil concentration gives more detrimental effect at high vapor qualities. The flow pattern map of R410A-oil mixture was developed based on refrigerant-oil mixture properties, and the observed flow patterns match well with the flow pattern map. New correlation to predict the local heat transfer of R410A-oil mixture flow boiling inside the straight smooth tube was developed based on flow patterns and local properties of refrigerant-oil mixture, and it agrees with 90% of the experiment data within the deviation of {+-}25%. (author)
Factors influencing the precoat filtration of boiling water reactor water streams
Hermansson, H.P. (Studsvik Material AB, Nykoeping (Sweden)); Persson, G. (Forsmark Nuclear Power Plant, Oesthammar (Sweden)); Reinvall, A. (Industrial Power Co. Ltd., Olkiluoto (Finland))
1994-10-01T23:59:59.000Z
A series of studies on precoat filtration were carried out on condensate and preheater drains in the Swedish and Finnish boiling water reactors (BWRs). The goal was to increase knowledge about the precoat filtration process and to find physical and chemical means to improve the performance of the precoat filters in the condensate polishing plants. To achieve this goal a number of parameters, such as type of resin, bed depth, pH, oxygen and organic contaminant concentrations (measured total organic carbon), and corrosion product particle characteristics, were selected for the study. The work was mainly carried out in the power plants using an experimental facility fed with on-line sampled condensates and drains taken from the plant sampling lines. The main results are that there is a varying influence on precoat filtration from all the aforementioned parameters. The oxygen concentration, the concentration of organic contaminants, and the type of corrosion products are, however, the factors that have the strongest influence within the parameter ranges that are representative for BWR operation. The results are rather similar when the different units are compared. There are, however, some differences that could be mainly attributed to deviations in operation parameters and the subsequent differences in the corrosion product spectra. The mechanism for precoat filtration of corrosion products in BWR condensate is complex. The filtration behavior is to a large extent governed by competition between depth filtration and electrostatic interactions. During the early stages of the filtration cycle, electrostatic interaction is of great importance, whereas depth filtration becomes more important with increasing operating time. Rapid pressure drop buildup rates have been demonstrated to be caused by the presence of amorphous corrosion products. An effect from the presence of organic contaminants has been found, although this should be of little significance.
Influences of electrical field on boiling-condensation heat transfer system
Yang Jiaxiang; Ding Lijian; Chi Xiaochun; Liu Ji [Harbin Inst. of Electrical Technology (China). Dept. of Electrical Materials Engineering; Yang He [Harbin Inst. of Tech. (China). Dept. of Thermal Energy Engineering
1996-12-31T23:59:59.000Z
In this paper, the influences of electrical field on boiling-condensation heat transfer system have been investigated using a cylinder heat transfer model. Freon-11 is selected as working fluid. The condensation heat transfer coefficient, the boiling heat flux and the saturation pressure are measured in this investigation. According to the experimental results, it is found that the electrical field can influence heat transfer system. The boiling heat transfer is enhanced by the applied voltage, and the saturate vapor of working fluid is condensed on the high voltage electrode directly when the applied voltage is higher than 6 kv. The experimental results have been discussed, and it is considered that the high electrical field strength change the thermal properties of working fluid.
Nikolayev, Vadim S.
that separates the liquid from the heater. Film boiling can be also observed in the kitchen by sprinkling water onto a hot frying pan. In spite of the large temperature of the heater (the pan) the water drops Boiling is a very efficient way to transfer heat from a heater to the liquid heat carrier. We discuss
Uniform asymptotic approximations of integrals
Khwaja, Sarah Farid
2014-07-01T23:59:59.000Z
In this thesis uniform asymptotic approximations of integrals are discussed. In order to derive these approximations, two well-known methods are used i.e., the saddle point method and the Bleistein method. To start with ...
Enhancement of pool boiling heat transfer with electrohydrodynamics and its fundamental study
Raghupathi, Sri Laxmi Priya
1998-01-01T23:59:59.000Z
, and 10kV. To conduct this study, an existing low pressure pool boiling apparatus was modified and another high pressure apparatus was designed and built. The fluids were tested on the smooth tube at operating temperatures of 4'C and 20'C, and 19 fins... TWl Tvvo Heat flux of EHD enhancement of boiling (W/m ) Total heat flux with EHD at 10kV (W/m ) Total heat flux with no EHD (W/m ) Minimum cavity mouth radius (m) Rayleigh number Fluid temperature ('C) Pool Saturation temperature ('C) Tube...
Tu, Chau Qui
1976-01-01T23:59:59.000Z
accepted. 3. Mass-transfer model: As early as 1952, the possi- 1. 1 bi) ity of mass transfer across the bubble was visualized oy Snyder and presented at a conference in 1856 for the ca. , e of subcool ed nucleate boiling in forced convection l qf. He... heat transfer in forced convection, found negligible latent heat transport compared to the total heat transferred from the heated surface. Ruling out the latent heat transport as major factor, they attributed the high heat transfer in boiling...
Danilova, G.N.; Reznikov, V.I.
1988-01-01T23:59:59.000Z
The authors propose a mathematical model for the intensification of boiling heat transfer and the subsequent increase in thermal efficiency of the cylindrical heat transfer surfaces in an evaporative cooling system. The boiling curves for water, ethanol, and freon 113 are calculated for a surface with artificial nucleation sites. The model incorporates such coolant properties as surface tension, specific heat, and vaporization heat.
Forrest, Eric Christopher
2009-01-01T23:59:59.000Z
Surface effects on pool boiling heat transfer and the critical heat flux are well documented but poorly understood. This study investigates the pool boiling characteristics of various fluids, and demonstrates that surface ...
Anh Bui; Nam Dinh; Brian Williams
2013-09-01T23:59:59.000Z
In addition to validation data plan, development of advanced techniques for calibration and validation of complex multiscale, multiphysics nuclear reactor simulation codes are a main objective of the CASL VUQ plan. Advanced modeling of LWR systems normally involves a range of physico-chemical models describing multiple interacting phenomena, such as thermal hydraulics, reactor physics, coolant chemistry, etc., which occur over a wide range of spatial and temporal scales. To a large extent, the accuracy of (and uncertainty in) overall model predictions is determined by the correctness of various sub-models, which are not conservation-laws based, but empirically derived from measurement data. Such sub-models normally require extensive calibration before the models can be applied to analysis of real reactor problems. This work demonstrates a case study of calibration of a common model of subcooled flow boiling, which is an important multiscale, multiphysics phenomenon in LWR thermal hydraulics. The calibration process is based on a new strategy of model-data integration, in which, all sub-models are simultaneously analyzed and calibrated using multiple sets of data of different types. Specifically, both data on large-scale distributions of void fraction and fluid temperature and data on small-scale physics of wall evaporation were simultaneously used in this work’s calibration. In a departure from traditional (or common-sense) practice of tuning/calibrating complex models, a modern calibration technique based on statistical modeling and Bayesian inference was employed, which allowed simultaneous calibration of multiple sub-models (and related parameters) using different datasets. Quality of data (relevancy, scalability, and uncertainty) could be taken into consideration in the calibration process. This work presents a step forward in the development and realization of the “CIPS Validation Data Plan” at the Consortium for Advanced Simulation of LWRs to enable quantitative assessment of the CASL modeling of Crud-Induced Power Shift (CIPS) phenomenon, in particular, and the CASL advanced predictive capabilities, in general. This report is prepared for the Department of Energy’s Consortium for Advanced Simulation of LWRs program’s VUQ Focus Area.
Simulation of subcooled boiling at low pressure conditions with RELAP5-3D computer program
Reza, S.M. Mohsin
2002-01-01T23:59:59.000Z
Simulation of subcooled boiling was carried out using RELAP5 thermal hydraulic computer programs. Both one-dimensional and three-dimensional analyses were carried out with one-dimensional RELAP5/MOD3.2 and three-dimensional RELAP5-3D code...
"Hot Water" in Lassen Volcanic National Park--Fumaroles, Steaming Ground, and Boiling Mudpots
Torgersen, Christian
"Hot Water" in Lassen Volcanic National Park-- Fumaroles, Steaming Ground, and Boiling Mudpots U, ydrothermal (hot water) and steaming ground. These features are re- lated to active volcanism, the largest fumarole (steam and volcanic-gas vent) in the park. The temperature of the high-velocity steam
Ferreira, Márcia M. C.
QSPR models of boiling point, octanolwater partition coefficient and retention time index StructureProperty Relationship (QSPR) analysis and study of polycyclic aromatic hydrocarbons (PAHs (bp), octanol water partition coefficient đlog KowŢ and retention time index (RI) for reversed
Development of a small-channel nucleate-boiling heat transfer correlation
Kasza, K.E.; Wambsganss, M.W.
1994-06-01T23:59:59.000Z
Development of an improved semimechanistic-based set of correlation parameters for nucleation-dominant flow-boiling heat transfer in small channels is described. Formulation of these parameters is on the basis of a recently published open-literature model for vapor bubble growth at a heated surface. This work is part of a program directed at obtaining an understanding of the physical mechanisms that influence boiling in compact heat exchangers through the use of high-speed video and microscope optics to characterize bubble nucleation, growth, and interaction with the confining walls of small heat transfer passages. The correlation parameters presented here represent the first step in the development of an improved boiling correlation for geometrically confined small-channel flows. In such flows, the nucleating bubbles can become nominally the same size as the channel cross section, thereby invalidating existing correlations that are based on large-channel data. Initial efforts to correlate small-channel-boiling data obtained at Argonne National Laboratory from nontransparent electrically heated metal tube tests appear promising.
2007-No54-BoilingPoint Health and Greenhouse Gas Impacts of Biomass and Fossil Fuel
Kammen, Daniel M.
2007-No54-BoilingPoint Theme Health and Greenhouse Gas Impacts of Biomass and Fossil Fuel Energy of fossil-fuel energy systems. These scenarios are analysed for various environmental and health impacts from fossil fuels and other energy sources reported by IEA []. In all of these countries except Kenya
Hydrodynamic cavitation and boiling in refrigerant (R-123) flow inside microchannels
Peles, Yoav
Hydrodynamic cavitation and boiling in refrigerant (R-123) flow inside microchannels Brandon cavitation has on heat transfer. The fluid medium is refrigerant R-123 flowing through 227 lm hydraulic diameter microchannels. The cavitation is instigated by the inlet orifice. Adiabatic tests were con- ducted
Numerical simulation of boiling during the quenching process N. Kosseifi1
Paris-Sud XI, Université de
by computing the heat flux that arises from the different modes of boiling. They coupled the phase change to heat dissipation of the metal thanks to an interface coupling code. The heat transfer coefficient using a level set method. Surface tension is evaluated using the continuum surface force. The proposed
A mathematical method for boiling water reactor control rod programming
Tokumasu, S.; Hiranuma, H.; Ozawa, M.; Yokomi, M.
1985-12-01T23:59:59.000Z
A new mathematical programming method has been developed and utilized in OPROD, an existing computer code for automatic generation of control rod programs as an alternative inner-loop routine for the method of approximate programming. The new routine is constructed of a dual feasible direction algorithm, and consists essentially of two stages of iterative optimization procedures Optimization Procedures I and II. Both follow almost the same algorithm; Optimization Procedure I searches for feasible solutions and Optimization Procedure II optimizes the objective function. Optimization theory and computer simulations have demonstrated that the new routine could find optimum solutions, even if deteriorated initial control rod patterns were given.
Supporting Text Approximation of the Multinomial. Using Stirling's approximation
Peterson, Carsten
Supporting Text Approximation of the Multinomial. Using Stirling's approximation n! (n/e)n 2n! . [S12] To calculate B L (^n) limN BN L (^n), we apply Stirling's formula to N!, n0!, and n1!, which that r Stirling's formula
Gerardi, Craig
High-speed video and infrared thermometry were used to obtain time- and space-resolved information on bubble nucleation and heat transfer in pool boiling of water. The bubble departure diameter and frequency, growth and ...
Development of models for the two-dimensional, two-fluid code for sodium boiling NATOF-2D
Zielinski, R. G.
1981-01-01T23:59:59.000Z
Several features were incorporated into NATOF-2D, a twodimensional, two fluid code developed at M.I.T. for the purpose of analysis of sodium boiling transients under LMFBR conditions. They include improved interfacial mass, ...
Estrada Perez, Carlos Eduardo
2014-12-12T23:59:59.000Z
In this work, visualization experimental techniques that provide whole-field and multi-scale measurements of the liquid turbulence parameters, liquid and heater wall temperatures, and gas phase local parameters, were used to study subcooled boiling...
Gilman, Lindsey Anne
2014-01-01T23:59:59.000Z
Advanced modeling capabilities were developed for application to subcooled flow boiling through this work. The target was to introduce, and demonstrate, all necessary mechanisms required to accurately predict the temperature ...
A four-equation two-phase flow model for sodium boiling simulation of LMFBR fuel assemblies
Schor, Andrei L.
1982-01-01T23:59:59.000Z
A three-dimensional numerical model for the simulation of sodium boiling transients has been developed. The model uses mixture mass and energy equations, while employing a separate momentum equation for each phase. Thermal ...
Film boiling on the inside of vertical tubes with upward flow of the fluid at low qualities
Dougall, R. S.
1963-01-01T23:59:59.000Z
Flow regimes, local heat transfer coefficients, and temperature distributions along the wall have been studied for film boiling inside a vertical tube with upward flow of a saturated liquid. The area of interest has been ...
Kim, Sung Joong, Ph. D. Massachusetts Institute of Technology
2009-01-01T23:59:59.000Z
A nanofluid is a colloidal suspension of nano-scale particles in water, or other base fluids. Previous pool boiling studies have shown that nanofluids can improve the critical heat flux (CHF) by as much as 200%. In this ...
Edwards, Bronwyn K
2009-01-01T23:59:59.000Z
An experimental study was performed to determine thermal performance and adhesion effects of a combined nanoparticle and polymeric dispersion coating. The critical heat flux (CHF) values and nucleate boiling heat transfer ...
Phillips, Bren Andrew
2014-01-01T23:59:59.000Z
Subcooled flow boiling of water was experimentally investigated using high-speed video (HSV), infrared (IR) thermography, and particle image velocimetry (PIV) to generate a unique database of synchronized data. HSV allowed ...
Mechanism design with approximate types
Zhu, Zeyuan Allen
2012-01-01T23:59:59.000Z
In mechanism design, we replace the strong assumption that each player knows his own payoff type exactly with the more realistic assumption that he knows it only approximately: each player i only knows that his true type ...
Two dimensional, two fluid model for sodium boiling in LMFBR fuel assemblies
Granziera, M.R.; Kazimi, M.S.
1980-05-01T23:59:59.000Z
A two dimensional numerical model for the simulation of sodium boiling transient was developed using the two fluid set of conservation equations. A semiimplicit numerical differencing scheme capable of handling the problems associated with the ill-posedness implied by the complex characteristic roots of the two fluid problems was used, which took advantage of the dumping effect of the exchange terms. Of particular interest in the development of the model was the identification of the numerical problems caused by the strong disparity between the axial and radial dimensions of fuel assemblies. A solution to this problem was found which uses the particular geometry of fuel assemblies to accelerate the convergence of the iterative technique used in the model. Three sodium boiling experiments were simulated with the model, with good agreement between the experimental results and the model predictions.
Transient approximations in queueing networks
Andrewartha, John Michael
1989-01-01T23:59:59.000Z
TRANSIENT APPROXIMATIONS IN QUEUEING NETWORKS A Thesis by JOHN MICHAEL ANDREWARTHA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1989... Major Subject: Electrical Engineering TRANSIENT APPROXIMATIONS IN QUEUEING NETWORKS A Thesis JOHN MICHAEL ANDREWARTHA Approved as to style and content by: P. E. Cantrell (Chair of Committee) m P7~ W. K. Tsai (Member) J. D. Gibson (Member) R...
Multi-scale Control and Enhancement of Reactor Boiling Heat Flux by Reagents and Nanoparticles
Manglik, R M; Athavale, A; Kalaikadal, D S; Deodhar, A; Verma, U
2011-09-02T23:59:59.000Z
The phenomenological characterization of the use of non-invasive and passive techniques to enhance the boiling heat transfer in water has been carried out in this extended study. It provides fundamental enhanced heat transfer data for nucleate boiling and discusses the associated physics with the aim of addressing future and next-generation reactor thermal-hydraulic management. It essentially addresses the hypothesis that in phase-change processes during boiling, the primary mechanisms can be related to the liquid-vapor interfacial tension and surface wetting at the solidliquid interface. These interfacial characteristics can be significantly altered and decoupled by introducing small quantities of additives in water, such as surface-active polymers, surfactants, and nanoparticles. The changes are fundamentally caused at a molecular-scale by the relative bulk molecular dynamics and adsorption-desorption of the additive at the liquid-vapor interface, and its physisorption and electrokinetics at the liquid-solid interface. At the micro-scale, the transient transport mechanisms at the solid-liquid-vapor interface during nucleation and bubblegrowth can be attributed to thin-film spreading, surface-micro-cavity activation, and micro-layer evaporation. Furthermore at the macro-scale, the heat transport is in turn governed by the bubble growth and distribution, macro-layer heat transfer, bubble dynamics (bubble coalescence, collapse, break-up, and translation), and liquid rheology. Some of these behaviors and processes are measured and characterized in this study, the outcomes of which advance the concomitant fundamental physics, as well as provide insights for developing control strategies for the molecular-scale manipulation of interfacial tension and surface wetting in boiling by means of polymeric reagents, surfactants, and other soluble surface-active additives.
Analytic approximate radiation effects due to Bremsstrahlung
Ben-Zvi I.
2012-02-01T23:59:59.000Z
The purpose of this note is to provide analytic approximate expressions that can provide quick estimates of the various effects of the Bremsstrahlung radiation produced relatively low energy electrons, such as the dumping of the beam into the beam stop at the ERL or field emission in superconducting cavities. The purpose of this work is not to replace a dependable calculation or, better yet, a measurement under real conditions, but to provide a quick but approximate estimate for guidance purposes only. These effects include dose to personnel, ozone generation in the air volume exposed to the radiation, hydrogen generation in the beam dump water cooling system and radiation damage to near-by magnets. These expressions can be used for other purposes, but one should note that the electron beam energy range is limited. In these calculations the good range is from about 0.5 MeV to 10 MeV. To help in the application of this note, calculations are presented as a worked out example for the beam dump of the R&D Energy Recovery Linac.
McEwan, Thomas E. (Livermore, CA)
1998-01-01T23:59:59.000Z
A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.
McEwan, T.E.
1998-06-16T23:59:59.000Z
A ``laser tape measure`` for measuring distance is disclosed which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%. 7 figs.
Analysis of the magnetic corrosion product deposits on a boiling water reactor cladding
Orlov, Andrey [Paul Scherrer Institut, Villigen (Switzerland); Degueldre, Claude, E-mail: claude.degueldre@psi.ch [Paul Scherrer Institut, Villigen (Switzerland); Kaufmann, Wilfried [Kernkraftwerk Leibstadt, Leibstadt (Switzerland)
2013-01-15T23:59:59.000Z
The buildup of corrosion product deposits (CRUD) on the fuel cladding of the boiling water reactor (BWR) before and after zinc injection has been investigated by applying local experimental analytical techniques. Under the BWR water chemistry conditions, Zn addition together with the presence of Ni and Mn induce the formation of (Zn,Ni,Mn)[Fe{sub 2}O{sub 4}] spinel solid solutions. X-ray absorption spectroscopy (XAS) revealed inversion ratios of cation distribution in spinels deposited from the solid solution. Based on this information, a two-site ferrite spinel solid solution model is proposed. Electron probe microanalysis (EPMA) and extended X-ray absorption fine structure (EXAFS) findings suggest the zinc-rich ferrite spinels formation on BWR fuel cladding mainly at lower pin. - Graphical Abstract: Analysis of spinels in corrosion product deposits on boiling water reactor fuel rod. Combining EPMA and XAFS results: schematic representation of the ferrite spinels in terms of the end members and their extent of inversion. Note that the ferrites are represented as a surface between the normal (upper plane, M[Fe{sub 2}]O{sub 4}) and the inverse (lower plane, Fe[MFe]O{sub 4}). Actual compositions red Black-Small-Square for the specimen at low elevation (810 mm), blue Black-Small-Square for the specimen at mid elevation (1800 mm). The results have an impact on the properties of the CRUD material. Highlights: Black-Right-Pointing-Pointer Buildup of corrosion product deposits on fuel claddings of a boiling water reactor (BWR) are investigated. Black-Right-Pointing-Pointer Under BWR water conditions, Zn addition with Ni and Mn induced formation of (Zn,Ni,Mn)[Fe{sub 2}O{sub 4}]. Black-Right-Pointing-Pointer X-Ray Adsorption Spectroscopy (XAS) revealed inversion of cations in spinel solid solutions. Black-Right-Pointing-Pointer Zinc-rich ferrite spinels are formed on BWR fuel cladding mainly at lower pin elevations.
Tu, Chau Qui
1976-01-01T23:59:59.000Z
par t of his t ime and labor to assist in the welding of thermocoupl-. junctions to the copper disk. And to all of those directly connected and to many others who helped by givino words of suggestion, there will always remain a debt o.... DEDICATION. AC (QU OWL EDGI"IENT S. TABLE OF CONTENTS. L1ST OF TABLES. LIST OF F IGUR ES. vi vii 1x CHAPTER I INTRODUCTION. CHAPTER II MECHANISMS OF NUCLEATE POOL BOILING. . . . . Bubble agitation model. Vapor-liquid exchange model. 3. M...
Convex approximations in stochastic programming by semidefinite ...
2010-04-19T23:59:59.000Z
This experience leads us to force the convexity of the approximating quadratic ..... As we can see, the least-squares approximation works well only if the data ...
Manglos, S.H.
1988-03-10T23:59:59.000Z
A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.
Non-ideal boson system in the Gaussian approximation
Tommasini, P.R. [Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)] [Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); de Toledo Piza, A.F. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05389-970 Sao Paulo, SP, (Brasil)] [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05389-970 Sao Paulo, SP, (Brasil)
1997-01-01T23:59:59.000Z
We investigate ground-state and thermal properties of a system of non-relativistic bosons interacting through repulsive, two-body interactions in a self-consistent Gaussian mean-field approximation which consists in writing the variationally determined density operator as the most general Gaussian functional of the quantized field operators. Finite temperature results are obtained in a grand canonical framework. Contact is made with the results of Lee, Yang, and Huang in terms of particular truncations of the Gaussian approximation. The full Gaussian approximation supports a free phase or a thermodynamically unstable phase when contact forces and a standard renormalization scheme are used. When applied to a Hamiltonian with zero range forces interpreted as an effective theory with a high momentum cutoff, the full Gaussian approximation generates a quasi-particle spectrum having an energy gap, in conflict with perturbation theory results. {copyright} 1997 Academic Press, Inc.
Magnetic thaw-down and boil-off due to magneto acceptors in 2DEG
Chaubet, C.; Raymond, A. [L2C UMR 5221, CNRS-Université Montpellier 2, Place E. Bataillon, 34090 Montpellier cedex 05 (France); Bisotto, I. [LNCMI, UPR 3228, CNRS-INSA-UJF-UPS, BP166, 38042 Grenoble, Cedex 9 (France); Harmand, J. C. [LPN, CNRS, route de Nozay, 91460 Marcoussis (France); Kubisa, M. [Institute of Physics, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Zawadzki, W. [Institute of Physics, Polish Academy of Sciences, 02668 Warsaw (Poland)
2013-12-04T23:59:59.000Z
The Quantum Hall Effect (QHE) and Shubnikov-de Haas effect are investigated experimentally using n type modulation-doped GaAs/GaAlAs quantum wells (QWs) additionally doped in the well with beryllium acceptor atoms. It is presently shown that the localized magneto-acceptor (MA) states which possess discrete energies above the corresponding Landau levels (LLs) lead to two observable effects in magneto-transport: magnetic thaw-down and magnetic boil-off of 2D electrons. Both effects are related to the fact that electrons occupying the localized MA states cannot conduct. Thus in the thaw-down effect the electrons fall down from the MA states to the free Landau states. This leads to a shift of the Hall plateau towards higher magnetic fields as a consequence of an increase of the 2D electron density N{sub S}. In the boil-off effect the electrons are pushed from the free Landau states to the empty MA states under high enough Hall electric field. This process has an avalanche character leading to a dramatic increase of magneto-resistance, consequence of a decrease of N{sub S}.
CORQUENCH: A model for gas sparging-enhanced, melt-water, film-boiling heat transfer
Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.
1990-01-01T23:59:59.000Z
In evaluation of severe-accident sequences for water-cooled nuclear reactors, molten core materials may be postulated to be released into the containment and accumulate on concrete. The heatup and decomposition of concrete is accompanied by the release of water vapor and carbon dioxide gases. Gases flowing through the melt upper surface can influence the rates of heat transfer to water overlying the melt. In particular, the gas flow through the interface can be envisioned to enhance the heat removal from the melt. A mechanistic model (CORQUENCH) has been developed to describe film-boiling heat transfer between a molten pool and an overlying coolant layer in the presence of sparging gas. The model favorably predicts the lead-Feron 11 data of Greene and Greene et al. for which the calculations indicate that area enhancement in the conduction heat transfer across the film is the predominant mechanism leading to augmentation in the heat flux as the gas velocity increases. Predictions for oxidic corium indicate a rapid increase in film-boiling heat flux as the gas velocity rises. The predominant mode of heat transfer for this case is radiation, and the increase in heat flux with gas velocity is primarily a result of interfacial area enhancement of the radiation component of the overall heat transfer coefficient. The CORQUENCH model has been incorporated into the MELTSPREAD-1 computer code{sup 6} for the analysis of transient spreading in containments.
Pool boiling of R-114/oil mixtures from single tubes and tube bundles. Master's thesis
Murphy, T.J.
1987-09-01T23:59:59.000Z
An apparatus was designed, fabricated, and operated for the testing of horizontal tube bundles for boiling of R-114 with various concentrations of oil. Preliminary data were taken on the top tube in the bundle, with and without the other tubes in operation. Results showed up to a 37% increase in the boiling heat-transfer coefficient as a result of the favorable bundle effect. In a separate single-tube apparatus, three enhanced tubes were tested at a saturation temperature of 2.2 C with oil mass concentrations of 0, 1, 2, 3, 6 and 10%. The tubes were: 1) a finned tube with 1024 fins per meter, 2) a finned tube with 1575 fins per meter and 3) a Turbo-B tube. These tubes resulted in enhancement ratios in pure refrigerant of 2.8, 3.8 and 5.2, respectively, at a practical heat flux of 30 kW/sq. meter. With 3% oil, these ratios were decreased to 2.6, 3.5 and 5, while with 10% oil, these ratios were further reduced to 2.6, 3.2 and 4.7, respectively. Based on these results, the use of Turbo-B tubes is expected to result in significant savings in weight and size of evaporators over the finned tubes presently in use on board some naval vessels.
Performance of Charcoal Cookstoves for Haiti Part 1: Results from the Water Boiling Test
Booker, Kayje; Han, Tae Won; Granderson, Jessica; Jones, Jennifer; Lsk, Kathleen; Yang, Nina; Gadgil, Ashok
2011-06-01T23:59:59.000Z
In April 2010, a team of scientists and engineers from Lawrence Berkeley National Lab (LBNL) and UC Berkeley, with support from the Darfur Stoves Project (DSP), undertook a fact-finding mission to Haiti in order to assess needs and opportunities for cookstove intervention. Based on data collected from informal interviews with Haitians and NGOs, the team, Scott Sadlon, Robert Cheng, and Kayje Booker, identified and recommended stove testing and comparison as a high priority need that could be filled by LBNL. In response to that recommendation, five charcoal stoves were tested at the LBNL stove testing facility using a modified form of version 3 of the Shell Foundation Household Energy Project Water Boiling Test (WBT). The original protocol is available online. Stoves were tested for time to boil, thermal efficiency, specific fuel consumption, and emissions of CO, CO{sub 2}, and the ratio of CO/CO{sub 2}. In addition, Haitian user feedback and field observations over a subset of the stoves were combined with the experiences of the laboratory testing technicians to evaluate the usability of the stoves and their appropriateness for Haitian cooking. The laboratory results from emissions and efficiency testing and conclusions regarding usability of the stoves are presented in this report.
Approximating Metal-Insulator Transitions
C. Danieli; K. Rayanov; B. Pavlov; G. Martin; S. Flach
2014-05-06T23:59:59.000Z
We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate metal-insulator transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges which are at variance to the celebrated Aubry-Andre model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase similar to the divergence of the localization length in the insulating phase.
Rebrov, P.N.; Bukin, V.G.; Danilova, G.N.
1989-07-01T23:59:59.000Z
Experimental results on the boiling of R12 and R22 on bundles of 30 to 50 vertically stacked rows of smooth tubes are presented and correlated. Engineering equations for determining the coefficients of heat transfer in the pool boiling of freons on such multirow bundles are derived.
Range of Glaciers: The Exploration of the Northern Cascade Range
Hook, Robert D.
2006-01-01T23:59:59.000Z
Review: Range of Glaciers: The Exploration of the NorthernUSA Fred Beckey. Range of Glaciers: The Exploration of thewill find that Range of Glaciers is a must read. The book
Kwatny, Harry G.
of steam pipe acoustics on the control of steam pressore in boiling waterreactors. A madel is developed forthe process which encompassesthe reactor vessel, the main steam piping, the bypasssystempiping in an increased steaming rate. The turbine admission valves would thenopen in responsetotheconsequent increase
Torgersen, Christian
). Conditions in Hot Creek can change very quickly. These fish--caught in a burst of high-temperature water" or intermittently spurting very hot, sediment-laden water as high as 6 feet (2 m) above the stream surface. At timesBoiling Water at Hot Creek--The Dangerous and Dynamic Thermal Springs in California's Long Valley
Peles, Yoav
across a bank of heated tube bundles, have shown that the local two-phase heat transfer coefficient across a tube bundle and determined the void fraction, the frictional pressure drop, and the local heatFlow boiling of water in a circular staggered micro-pin fin heat sink Santosh Krishnamurthy, Yoav
Operational experience with and post-irradiation examinations on boiling water reactor control rods
Eickelpash, N.; Mullauer, J.; Seepolt, R.W.; Spalthoff, W.
1983-03-01T23:59:59.000Z
The control rods of the KRB-I 250-MW (electric) boiling water reactor contain Vipac B/sub 4/C powder in Type 304 stainless steel tubes as a neutron-absorbing material. Because of an increase in the reactor coolant /sup 3/H activity, defective control rods were suspected. The hot cell examination of a highly exposed control rod revealed B/sub 4/C losses. The mechanism of failure was shown to be B/sub 4/C swelling and stress corrosion cracking of the absorber tubes, followed by B/sub 4/C washout. The B/sub 4/C volume swelling is given. The tube cracking starts at 30 to 35% and the B/sub 4/C washout at 50 to 55% local /sup 10/B burnup in the tubes.
Passive containment cooling system with drywell pressure regulation for boiling water reactor
Hill, P.R.
1994-12-27T23:59:59.000Z
A boiling water reactor is described having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit. 4 figures.
Passive containment cooling system with drywell pressure regulation for boiling water reactor
Hill, Paul R. (Tucson, AZ)
1994-01-01T23:59:59.000Z
A boiling water reactor having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit.
Nelson, R.A.; Unal, C.
1991-01-01T23:59:59.000Z
In this paper, a phenomenological model of the thermal hydraulics of convective boiling in the post-critical-heat-flux (post-CHF) regime is developed and discussed. The model was implemented in the TRAC-PF1/MOD2 computer code (an advanced best-estimate computer program written for the analysis of pressurized water reactor systems). The model was built around the determination of flow regimes downstream of the quench front. The regimes were determined from the flow-regime map suggested by Ishii and his coworkers. Heat transfer in the transition boiling region was formulated as a position-dependent model. The propagation of the CHF point was strongly dependent on the length of the transition boiling region. Wall-to-fluid film boiling heat transfer was considered to consist of two components: first, a wall-to-vapor convective heat-transfer portion and, second, a wall-to-liquid heat transfer representing near-wall effects. Each contribution was considered separately in each of the inverted annular flow (IAF) regimes. The interfacial heat transfer was also formulated as flow-regime dependent. The interfacial drag coefficient model upstream of the CHF point was considered to be similar to flow through a roughened pipe. A free-stream contribution was calculated using Ishii's bubbly flow model for either fully developed subcooled or saturated nucleate boiling. For the drag in the smooth IAF region, a simple smooth-tube correlation for the interfacial friction factor was used. The drag coefficient for the rough-wavy IAF was formulated in the same way as for the smooth IAF model except that the roughness parameter was assumed to be proportional to liquid droplet diameter entrained from the wavy interface. The drag coefficient in the highly dispersed flow regime considered the combined effects of the liquid droplets within the channel and a liquid film on wet unheated walls. 431 refs., 6 figs., 4 tabs.
Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications
Bang, In C [ORNL; Buongiorno, Jdacopo [Massachusetts Institute of Technology (MIT); Hu, Lin-wen [Massachusetts Institute of Technology (MIT); Wang, Hsin [ORNL
2007-01-01T23:59:59.000Z
Nanofluids, colloidal dispersions of nanoparticles in a base fluid such as water, can afford very significant Critical Heat Flux (CHF) enhancement. Such engineered fluids potentially could be employed in reactors as advanced coolants in safety systems with significant safety and economic advantages. However, a satisfactory explanation of the CHF enhancement mechanism in nanofluids is lacking. To close this gap, we have identified the important boiling parameters to be measured. These are the properties (e.g., density, viscosity, thermal conductivity, specific heat, vaporization enthalpy, surface tension), hydrodynamic parameters (i.e., bubble size, bubble velocity, departure frequency, hot/dry spot dynamics) and surface conditions (i.e., contact angle, nucleation site density). We have also deployed a pool boiling facility in which many such parameters can be measured. The facility is equipped with a thin indium-tin-oxide heater deposited over a sapphire substrate. An infra-red high-speed camera and an optical probe are used to measure the temperature distribution on the heater and the hydrodynamics above the heater, respectively. The first data generated with this facility already provide some clue on the CHF enhancement mechanism in nanofluids. Specifically, the progression to burnout in a pure fluid (ethanol in this case) is characterized by a smoothly-shaped and steadily-expanding hot spot. By contrast, in the ethanol-based nanofluid the hot spot pulsates and the progression to burnout lasts longer, although the nanofluid CHF is higher than the pure fluid CHF. The presence of a nanoparticle deposition layer on the heater surface seems to enhance wettability and aid hot spot dissipation, thus delaying burnout.
Reflectance Function Approximation for Material Classification
Dyer, Charles R.
Reflectance Function Approximation for Material Classification Edward Wild CS 766 Final Project This report summarizes the results of a project to approximate reflectance functions and classify materials to classify materials. Classification algorithms are proposed to deal with unseen materials. Experimental
Kinetic Modeling and Thermodynamic Closure Approximation of ...
2007-10-03T23:59:59.000Z
Oct 5, 2007 ... Kinetic Modeling and Thermodynamic Closure. Approximation of Liquid Crystal Polymers. Haijun Yu. Program in Applied and Computational ...
Fast Local Approximation to Global Illumination
Wyman, Chris
based technique #12;Approach to Shadows Â· Assume: Â Approximate shadow umbra with hard shadow Â Object
Duan, Xiaoman
Nucleation, growth, and detachment of steam bubbles during nucleate boiling of a water pool at atmospheric pressure is experimentally investigated using a combination of synchronized high-speed video, infrared thermography, ...
Sugrue, Rosemary M
2012-01-01T23:59:59.000Z
The effects of orientation angle, subcooling, heat flux, mass flux, and pressure on bubble growth and detachment in subcooled flow boiling were studied using a high-speed video camera in conjunction with a two-phase flow ...
No, Hee Cheon
1983-01-01T23:59:59.000Z
This work involves the development of physical models for the constitutive relations of a two-fuid, three-dimensional sodium boiling code, THERMIT-6S. The code is equipped with a fluid conduction model, a fuel pin model, ...
Gerardi, Craig Douglas
2009-01-01T23:59:59.000Z
A high-speed video and infrared thermography based technique has been used to obtain detailed and fundamental time- and space-resolved information on pool boiling heat transfer. The work is enabled by recent advances in ...
Design of a boiling water reactor equilibrium core using thorium-uranium fuel
Francois, J-L.; Nunez-Carrera, A.; Espinosa-Paredes, G.; Martin-del-Campo, C.
2004-10-06T23:59:59.000Z
In this paper the design of a Boiling Water Reactor (BWR) equilibrium core using thorium is presented; a heterogeneous blanket-seed core arrangement concept was adopted. The design was developed in three steps: in the first step two different assemblies were designed based on the integrated blanket-seed concept, they are the blanket-dummy assembly and the blanket-seed assembly. The integrated blanketseed concept comes from the fact that the blanket and the seed rods are located in the same assembly, and are burned-out in a once-through cycle. In the second step, a core design was developed to achieve an equilibrium cycle of 365 effective full power days in a standard BWR with a reload of 104 fuel assemblies designed with an average 235U enrichment of 7.5 w/o in the seed sub-lattice. The main operating parameters, like power, linear heat generation rate and void distributions were obtained as well as the shutdown margin. It was observed that the analyzed parameters behave like those obtained in a standard BWR. The shutdown margin design criterion was fulfilled by addition of a burnable poison region in the assembly. In the third step an in-house code was developed to evaluate the thorium equilibrium core under transient conditions. A stability analysis was also performed. Regarding the stability analysis, five operational states were analyzed; four of them define the traditional instability region corner of the power-flow map and the fifth one is the operational state for the full power condition. The frequency and the boiling length were calculated for each operational state. The frequency of the analyzed operational states was similar to that reported for BWRs; these are close to the unstable region that occurs due to the density wave oscillation phenomena in some nuclear power plants. Four transient analyses were also performed: manual SCRAM, recirculation pumps trip, main steam isolation valves closure and loss of feed water. The results of these transients are similar to those obtained with the traditional UO2 nuclear fuel.
Finite element approximation of coupled seismic and ...
zyserman
layer, having a thickness of about 10 nm. Finite element approximation of coupled seismic and electromagnetic waves in gas hydrate-bearing sediments – p.
Optimization Online - Equivalence of an Approximate Linear ...
Alejandro Toriello
2013-02-07T23:59:59.000Z
Feb 7, 2013 ... Equivalence of an Approximate Linear Programming Bound with the Held-Karp Bound for the Traveling Salesman Problem. Alejandro Toriello ...
Optimization Online - Probabilistic optimization via approximate p ...
W. van vAckooij
2015-05-27T23:59:59.000Z
May 27, 2015 ... Probabilistic optimization via approximate p-efficient points and bundle methods. W. van vAckooij(wim.van-ackooij ***at*** edf.fr )
Successive Convex Approximations to Cardinality-Constrained ...
2012-04-16T23:59:59.000Z
Replacing the ?0-norm (car- dinality) constraint in (P) by the above DC approximation ?(x, t), we obtain the following quadratic program with a DC constraint: (Pt).
Approximations by Orthonormal Mapped Chebyshev Functions for ...
2014-03-12T23:59:59.000Z
a School of Mathematical Science, Xiamen University, 361005 Xiamen, China .... suitable mapping can be used to approximate functions on the whole line R (cf.
Section 2.5: Approximations Using Increments
2014-04-05T23:59:59.000Z
Feb 26, 2014 ... Lesson 19. Definition. Examples. In this lesson we will discuss a method for approximating the value of a function at a specified point.
Study of plutonium disposition using existing GE advanced Boiling Water Reactors
Not Available
1994-06-01T23:59:59.000Z
The end of the cold war and the resulting dismantlement of nuclear weapons has resulted in the need for the US to dispose of 50 to 100 metric tons of excess of plutonium in a safe and proliferation resistant manner. A number of studies, including the recently released National Academy of Sciences (NAS) study, have recommended conversion of plutonium into spent nuclear fuel with its high radiation barrier as the best means of providing permanent conversion and long-term diversion resistance to this material. The NAS study ``Management and Disposition of Excess Weapons Plutonium identified Light Water Reactor spent fuel as the most readily achievable and proven form for the disposition of excess weapons plutonium. The study also stressed the need for a US disposition program which would enhance the prospects for a timely reciprocal program agreement with Russia. This summary provides the key findings of a GE study where plutonium is converted into Mixed Oxide (MOX) fuel and a typical 1155 MWe GE Boiling Water Reactor (BWR) is utilized to convert the plutonium to spent fuel. A companion study of the Advanced BWR has recently been submitted. The MOX core design work that was conducted for the ABWR enabled GE to apply comparable fuel design concepts and consequently achieve full MOX core loading which optimize plutonium throughput for existing BWRs.
Operational experience with and postirradiation examinations on boiling water reactor control rods
Eickelpasch, N.; Seepolt, R.W.; Muellauer, J.; Spalthoff, W.
1983-03-01T23:59:59.000Z
The control rods of the KRBI-I 250-MW(electric) boiling water reactor contain Vipac B/sub 4/C powder in Type 304 stainless steel tubes as a neutron-absorbing material. Because of an increase in the reactor coolant /sup 3/H activity, defective control rods were suspected. The hot cell examination of a highly exposed control rod revealed B/sub 4/C losses. The mechanism of failure was shown to be B/sub 4/C swelling and stress corrosion cracking of the absorber tubes, followed by B/sub 4/C washout. The B/sub 4/C volume swelling is ..delta..V(%) = 0.851x + 0.0449x/sup 2/ (x = /sup 10/B decays in 10/sup 21/(n,..cap alpha..)/cm/sup 3/). The tube cracking starts at 30 to 35% and the B/sub 4/C washout at 50 to 55% local /sup 10/B burnup in the tubes.
Results of the DF-4 BWR (boiling water reactor) control blade-channel box test
Gauntt, R.O.; Gasser, R.D.
1990-10-01T23:59:59.000Z
The DF-4 in-pile fuel damage experiment investigated the behavior of boiling water reactor (BWR) fuel canisters and control blades in the high temperature environment of an unrecovered reactor accident. This experiment, which was carried out in the Annular Core Research Reactor (ACRR) at Sandia National Laboratories, was performed under the USNRC's internationally sponsored severe fuel damage (SFD) program. The DF-4 test is described herein and results from the experiment are presented. Important findings from the DF-4 test include the low temperature melting of the stainless steel control blade caused by reaction with the B{sub 4}C, and the subsequent low temperature attack of the Zr-4 channel box by the relocating molten blade components. Hydrogen generation was found to continue throughout the experiment, diminishing slightly following the relocation of molten oxidizing zircaloy to the lower extreme of the test bundle. A large blockage which was formed from this material continued to oxidize while steam was being fed into the the test bundle. The results of this test have provided information on the initial stages of core melt progression in BWR geometry involving the heatup and cladding oxidation stages of a severe accident and terminating at the point of melting and relocation of the metallic core components. The information is useful in modeling melt progression in BWR core geometry, and provides engineering insight into the key phenomena controlling these processes. 12 refs., 12 figs.
Wavelet-Based Method for Instability Analysis in Boiling Water Reactors
Espinosa-Paredes, Gilberto; Prieto-Guerrero, Alfonso; Nunez-Carrera, Alejandro; Amador-Garcia, Rodolfo
2005-09-15T23:59:59.000Z
This paper introduces a wavelet-based method to analyze instability events in a boiling water reactor (BWR) during transient phenomena. The methodology to analyze BWR signals includes the following: (a) the short-time Fourier transform (STFT) analysis, (b) decomposition using the continuous wavelet transform (CWT), and (c) application of multiresolution analysis (MRA) using discrete wavelet transform (DWT). STFT analysis permits the study, in time, of the spectral content of analyzed signals. The CWT provides information about ruptures, discontinuities, and fractal behavior. To detect these important features in the signal, a mother wavelet has to be chosen and applied at several scales to obtain optimum results. MRA allows fast implementation of the DWT. Features like important frequencies, discontinuities, and transients can be detected with analysis at different levels of detail coefficients. The STFT was used to provide a comparison between a classic method and the wavelet-based method. The damping ratio, which is an important stability parameter, was calculated as a function of time. The transient behavior can be detected by analyzing the maximum contained in detail coefficients at different levels in the signal decomposition. This method allows analysis of both stationary signals and highly nonstationary signals in the timescale plane. This methodology has been tested with the benchmark power instability event of Laguna Verde nuclear power plant (NPP) Unit 1, which is a BWR-5 NPP.
Thiagarajan, S. J.; Wang, W.; Yang, R.; Narumanchi, S.; King, C.
2010-09-01T23:59:59.000Z
The DOE National Renewable Energy Laboratory (NREL) is leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. The goal is to reduce the size, weight, and cost of power electronic modules that convert direct current from batteries to alternating current for the motor, and vice versa. Aggressive thermal management techniques help to increase power density and reduce weight and volume, while keeping chip temperatures within acceptable limits. The viability of aggressive cooling schemes such as spray and jet impingement in conjunction with enhanced surfaces is being explored. Here, we present results from a series of experiments with pool and spray boiling on enhanced surfaces, such as a microporous layer of copper and copper nanowires, using HFE-7100 as the working fluid. Spray impingement on the microporous coated surface showed an enhancement of 100%-300% in the heat transfer coefficient at a given wall superheat with respect to spray impingement on a plain surface under similar operating conditions. Critical heat flux also increased by 7%-20%, depending on flow rates.
The Neutronics Design and Analysis of a 200-MW(electric) Simplified Boiling Water Reactor Core
Tinkler, Daniel R.; Downar, Thomas J. [Purdue University (United States)
2003-06-15T23:59:59.000Z
A 200-MW(electric) simplified boiling water reactor (SBWR) was designed and analyzed under sponsorship of the U.S. Department of Energy Nuclear Energy Research Initiative program. The compact size of a 200-MW(electric) reactor makes it attractive for countries with a less well developed engineering infrastructure, as well as for developed countries seeking to tailor generation capacity more closely to the growth of their electricity demand. The 200-MW(electric) core design reported here is based on the 600-MW(electric) General Electric SBWR core, which was first analyzed in the work performed here in order to qualify the computer codes used in the analysis. Cross sections for the 8 x 8 fuel assembly design were generated with the HELIOS lattice physics code, and core simulation was performed with the U.S. Nuclear Regulatory Commission codes RELAP5/PARCS. In order to predict the critical heat flux, the Hench-Gillis correlation was implemented in the RELAP5 code. An equilibrium cycle was designed for the 200-MW(electric) core, which provided a cycle length of more than 2 yr and satisfied the minimum critical power ratio throughout the core life.
FORMOSA-B: A Boiling Water Reactor In-Core Fuel Management Optimization Package II
Karve, Atul A.; Turinsky, Paul J. [North Carolina State University (United States)
2000-07-15T23:59:59.000Z
As part of the continuing development of the boiling water reactor in-core fuel management optimization code FORMOSA-B, the fidelity of the core simulator has been improved and a control rod pattern (CRP) sampling capability has been added. The robustness of the core simulator is first demonstrated by benchmarking against core load-follow depletion predictions of both SIMULATE-3 and MICROBURN-B2 codes. The CRP sampling capability, based on heuristic rules, is next successfully tested on a fixed fuel loading pattern (LP) to yield a feasible CRP that removes the thermal margin and critical flow constraint violations. Its performance in facilitating a spectral shift flow operation is also demonstrated, and then its significant influence on the cost of thermal margin is presented. Finally, the heuristic CRP sampling capability is coupled with the stochastic LP optimization capability in FORMOSA-B - based on simulated annealing (SA) - to solve the combined CRP-LP optimization problem. Effectiveness of the sampling in improving the efficiency of the SA adaptive algorithm is shown by comparing the results to those obtained with the sampling turned off (i.e., only LP optimization is carried out for the fixed reference CRP). The results presented clearly indicate the successful implementation of the CRP sampling algorithm and demonstrate FORMOSA-B's enhanced optimization features, which facilitate the code's usage for broader optimization studies.
Corrections to Eikonal Approximation for Nuclear Scattering at Medium Energies
Micah Buuck; Gerald A. Miller
2014-06-12T23:59:59.000Z
The upcoming Facility for Rare Isotope Beams (FRIB) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University has reemphasized the importance of accurate modeling of low energy nucleus-nucleus scattering. Such calculations have been simplified by using the eikonal approximation. As a high energy approximation, however, its accuracy suffers for the medium energy beams that are of current experimental interest. A prescription developed by Wallace \\cite{Wallace:1971zz,Wallace:1973iu} that obtains the scattering propagator as an expansion around the eikonal propagator (Glauber approach) has the potential to extend the range of validity of the approximation to lower energies. Here we examine the properties of this expansion, and calculate the first-, second-, and third-order corrections for the scattering of a spinless particle off of a ${}^{40}$Ca nucleus, and for nuclear breakup reactions involving ${}^{11}$Be. We find that, including these corrections extends the lower bound of the range of validity of the down to energies of 40 MeV. At that energy the corrections provide as much as a 15\\% correction to certain processes.
Blood Management Using Approximate Linear Programming
Shenoy, Prashant
Blood Management Using Approximate Linear Programming Marek Petrik and Shlomo Zilberstein January 13th, 2009 Marek Petrik and Shlomo Zilberstein () Blood Management Using Approximate Linear ProgrammingJanuary 13th, 2009 1 / 36 #12;Blood Inventory Management Problem Regional blood banks: Aggregate
Approximate error conjugation gradient minimization methods
Kallman, Jeffrey S
2013-05-21T23:59:59.000Z
In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.
Extended range chemical sensing apparatus
Hughes, Robert C. (Albuquerque, NM); Schubert, W. Kent (Albuquerque, NM)
1994-01-01T23:59:59.000Z
An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.
Extended range chemical sensing apparatus
Hughes, R.C.; Schubert, W.K.
1994-01-18T23:59:59.000Z
An apparatus is described for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy. 6 figures.
The effect of surface conditions on nuceate pool boiling heat transfer to sodium
Marto, P. J.
1965-01-01T23:59:59.000Z
A simplified theoretical model for bubble nucleation stability has been proposed, and an approximate stability criterion has been developed. This criterion contains both fluid and surfqce properties, and it predicts that ...
Quantum optimal control within the rotating wave approximation
Maximilian Keck; Matthias M. Müller; Tommaso Calarco; Simone Montangero
2015-03-06T23:59:59.000Z
We study the interplay between rotating wave approximation and optimal control. In particular, we show that for a wide class of optimal control problems one can choose the control field such that the Hamiltonian becomes time-independent under the rotating wave approximation. Thus, we show how to recast the functional minimization defined by the optimal control problem into a simpler multi-variable function minimization. We provide the analytic solution to the state-to-state transfer of the paradigmatic two-level system and to the more general star configuration of an $N$-level system. We demonstrate numerically the usefulness of this approach in the more general class of connected acyclic $N$-level systems with random spectra. Finally, we use it to design a protocol to entangle Rydberg via constant laser pulses atoms in an experimentally relevant range of parameters.
Quasielastic electron-deuteron scattering in the weak binding approximation
Ethier, Jacob J. [William and Mary College, JLAB; Doshi, Nidhi P. [Carnegie Mellon University; Malace, Simona P. [JLAB; Melnitchouk, Wally [JLAB
2014-06-01T23:59:59.000Z
We perform a global analysis of all available electron-deuteron quasielastic scattering data using Q^2-dependent smearing functions that describe inclusive inelastic e-d scattering within the weak binding approximation. We study the dependence of the cross sections on the deuteron wave function and the off-shell extrapolation of the elastic electron-nucleon cross section, which show particular sensitivity at x >> 1. The excellent overall agreement with data over a large range of Q^2 and x suggest a limited need for effects beyond the impulse approximation, with the exception of the very high-x or very low-Q^2 regions, where short-distance effects in the deuteron become more relevant.
Wave-mechanics and the adhesion approximation
C. J. Short; P. Coles
2006-11-22T23:59:59.000Z
The dynamical equations describing the evolution of a self-gravitating fluid of cold dark matter (CDM) can be written in the form of a Schrodinger equation coupled to a Poisson equation describing Newtonian gravity. It has recently been shown that, in the quasi-linear regime, the Schrodinger equation can be reduced to the exactly solvable free-particle Schrodinger equation. The free-particle Schrodinger equation forms the basis of a new approximation scheme -the free-particle approximation - that is capable of evolving cosmological density perturbations into the quasi-linear regime. The free-particle approximation is essentially an alternative to the adhesion model in which the artificial viscosity term in Burgers' equation is replaced by a non-linear term known as the quantum pressure. Simple one-dimensional tests of the free-particle method have yielded encouraging results. In this paper we comprehensively test the free-particle approximation in a more cosmologically relevant scenario by appealing to an N-body simulation. We compare our results with those obtained from two established methods: the linearized fluid approach and the Zeldovich approximation. We find that the free-particle approximation comprehensively out-performs both of these approximation schemes in all tests carried out and thus provides another useful analytical tool for studying structure formation on cosmological scales.
Study of plutonium disposition using the GE Advanced Boiling Water Reactor (ABWR)
NONE
1994-04-30T23:59:59.000Z
The end of the cold war and the resulting dismantlement of nuclear weapons has resulted in the need for the U.S. to disposition 50 to 100 metric tons of excess of plutonium in parallel with a similar program in Russia. A number of studies, including the recently released National Academy of Sciences (NAS) study, have recommended conversion of plutonium into spent nuclear fuel with its high radiation barrier as the best means of providing long-term diversion resistance to this material. The NAS study {open_quotes}Management and Disposition of Excess Weapons Plutonium{close_quotes} identified light water reactor spent fuel as the most readily achievable and proven form for the disposition of excess weapons plutonium. The study also stressed the need for a U.S. disposition program which would enhance the prospects for a timely reciprocal program agreement with Russia. This summary provides the key findings of a GE study where plutonium is converted into Mixed Oxide (MOX) fuel and a 1350 MWe GE Advanced Boiling Water Reactor (ABWR) is utilized to convert the plutonium to spent fuel. The ABWR represents the integration of over 30 years of experience gained worldwide in the design, construction and operation of BWRs. It incorporates advanced features to enhance reliability and safety, minimize waste and reduce worker exposure. For example, the core is never uncovered nor is any operator action required for 72 hours after any design basis accident. Phase 1 of this study was documented in a GE report dated May 13, 1993. DOE`s Phase 1 evaluations cited the ABWR as a proven technical approach for the disposition of plutonium. This Phase 2 study addresses specific areas which the DOE authorized as appropriate for more in-depth evaluations. A separate report addresses the findings relative to the use of existing BWRs to achieve the same goal.
MODULAR AND FULL SIZE SIMPLIFIED BOILING WATER REACTOR DESIGN WITH FULLY PASSIVE SAFETY SYSTEMS
M. Ishii; S. T. Revankar; T. Downar; Y. Xu, H. J. Yoon; D. Tinkler; U. S. Rohatgi
2003-06-16T23:59:59.000Z
OAK B204 The overall goal of this three-year research project was to develop a new scientific design of a compact modular 200 MWe and a full size 1200 MWe simplified boiling water reactors (SBWR). Specific objectives of this research were: (1) to perform scientific designs of the core neutronics and core thermal-hydraulics for a small capacity and full size simplified boiling water reactor, (2) to develop a passive safety system design, (3) improve and validate safety analysis code, (4) demonstrate experimentally and analytically all design functions of the safety systems for the design basis accidents (DBA) and (5) to develop the final scientific design of both SBWR systems, 200 MWe (SBWR-200) and 1200 MWe (SBWR-1200). The SBWR combines the advantages of design simplicity and completely passive safety systems. These advantages fit well within the objectives of NERI and the Department of Energy's focus on the development of Generation III and IV nuclear power. The 3-year research program was structured around seven tasks. Task 1 was to perform the preliminary thermal-hydraulic design. Task 2 was to perform the core neutronic design analysis. Task 3 was to perform a detailed scaling study and obtain corresponding PUMA conditions from an integral test. Task 4 was to perform integral tests and code evaluation for the DBA. Task 5 was to perform a safety analysis for the DBA. Task 6 was to perform a BWR stability analysis. Task 7 was to perform a final scientific design of the compact modular SBWR-200 and the full size SBWR-1200. A no cost extension for the third year was requested and the request was granted and all the project tasks were completed by April 2003. The design activities in tasks 1, 2, and 3 were completed as planned. The existing thermal-hydraulic information, core physics, and fuel lattice information was collected on the existing design of the simplified boiling water reactor. The thermal-hydraulic design were developed. Based on a detailed integral system scaling analysis, design parameters were obtained and designs of the compact modular 200 MWe SBWR and the full size 1200 MWe SBWR were developed. These reactors are provided with passive safety systems. A new passive vacuum breaker check valve was designed to replace the mechanical vacuum beaker check valve. The new vacuum breaker check valve was based on a hydrostatic head, and was fail safe. The performance of this new valve was evaluated both by the thermal-hydraulic code RELAP5 and by the experiments in a scaled SBWR facility, PUMA. In the core neutronic design a core depletion model was implemented to PARCS code. A lattice design for the SBWR fuel assemblies was performed. Design improvements were made to the neutronics/thermal-hydraulics models of SBWR-200 and SBWR-1200, and design analyses of these reactors were performed. The design base accident analysis and evaluation of all the passive safety systems were completed as scheduled in tasks 4 and 5. Initial conditions for the small break loss of coolant accidents (LOCA) and large break LOCA using REALP5 code were obtained. Small and large break LOCA tests were performed and the data was analyzed. An anticipated transient with scram was simulated using the RELAP5 code for SBWR-200. The transient considered was an accidental closure of the main steam isolation valve (MSIV), which was considered to be the most significant transient. The evaluation of the RELAP5 code against experimental data for SBWR-1200 was completed. In task 6, the instability analysis for the three SBWR designs (SBWR-1200, SBWR-600 and SBWR-200) were simulated for start-up transients and the results were similar. Neither the geysering instability, nor the loop type instability was predicted by RAMONA-4B in the startup simulation following the recommended procedure by GE. The density wave oscillation was not observed at all because the power level used in the simulation was not high enough. A study was made of the potential instabilities by imposing an unrealistically high power ramp in a short time period, as suggested by GE. RAMON
Compton scattering from positronium and validity of the impulse approximation
Kaliman, Z.; Pisk, K.; Pratt, R. H. [Department of Physics, University of Rijeka, Rijeka (Croatia); Rudjer Boskovic Institute, P. O. Box 180, Zagreb (Croatia) and University of Dubrovnik, Dubrovnik (Croatia); Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
2011-05-15T23:59:59.000Z
The cross sections for Compton scattering from positronium are calculated in the range from 1 to 100 keV incident photon energy. The calculations are based on the A{sup 2} term of the photon-electron or photon-positron interaction. Unlike in hydrogen, the scattering occurs from two centers and the interference effect plays an important role for energies below 8 keV. Because of the interference, the criterion for validity of the impulse approximation for positronium is more restrictive compared to that for hydrogen.
Optimization of Multibody Systems using Approximation Concepts
Etman, L.F. Pascal
UNIVERSITEIT EINDHOVEN Optimization of multibody systems using approximation concepts / Lodewijk Franciscus Pascal Etman. - Eindhoven : Technische Universiteit Eindhoven, 1997. - XVIII, 140 p. - With ref concepts / crashworthiness design / vehicle suspension Druk: Universiteitsdrukkerij TU Eindhoven Support
Hardness of approximation for quantum problems
Sevag Gharibian; Julia Kempe
2012-09-05T23:59:59.000Z
The polynomial hierarchy plays a central role in classical complexity theory. Here, we define a quantum generalization of the polynomial hierarchy, and initiate its study. We show that not only are there natural complete problems for the second level of this quantum hierarchy, but that these problems are in fact hard to approximate. Using these techniques, we also obtain hardness of approximation for the class QCMA. Our approach is based on the use of dispersers, and is inspired by the classical results of Umans regarding hardness of approximation for the second level of the classical polynomial hierarchy [Umans, FOCS 1999]. The problems for which we prove hardness of approximation for include, among others, a quantum version of the Succinct Set Cover problem, and a variant of the local Hamiltonian problem with hybrid classical-quantum ground states.
Approximation algorithms for QMA-complete problems
Sevag Gharibian; Julia Kempe
2011-01-20T23:59:59.000Z
Approximation algorithms for classical constraint satisfaction problems are one of the main research areas in theoretical computer science. Here we define a natural approximation version of the QMA-complete local Hamiltonian problem and initiate its study. We present two main results. The first shows that a non-trivial approximation ratio can be obtained in the class NP using product states. The second result (which builds on the first one), gives a polynomial time (classical) algorithm providing a similar approximation ratio for dense instances of the problem. The latter result is based on an adaptation of the "exhaustive sampling method" by Arora et al. [J. Comp. Sys. Sci. 58, p.193 (1999)] to the quantum setting, and might be of independent interest.
Optimization Online - An Approximation Algorithm for Constructing ...
Artur Pessoa
2006-09-02T23:59:59.000Z
Sep 2, 2006 ... In this paper, we propose an approximation algorithm for the 2-bit Hamming prefix code problem. Our algorithm spends $O(n \\log^3 n)$ time to ...
RESTRICTED-TRACE APPROXIMATION FOR NUCLEAR ANTIFERROMAGNETISM
Boyer, Edmond
1353 RESTRICTED-TRACE APPROXIMATION FOR NUCLEAR ANTIFERROMAGNETISM M. GOLDMAN and G. SARMA Service to predict several properties of nuclear antiferromagnetic structures : sublattice magnetization of nuclear dipolar magnetic ordering, either antiferromagnetic or ferromagnetic, has been reported
Approximate Bivariate Factorization, a Geometric Andre Galligo
Hoeij, Mark van
INRIA) Laboratoire de Mathematiques Parc Valrose 06108 Nice cedex 02, France galligo@unice.fr Mark van, Maple Code 1. INTRODUCTION 1.1 Approximate algebra Over the past ten years symbolic-numeric algorithms
Optimization in Geometric Graphs: Complexity and Approximation
Kahruman-Anderoglu, Sera
2011-02-22T23:59:59.000Z
We consider several related problems arising in geometric graphs. In particular, we investigate the computational complexity and approximability properties of several optimization problems in unit ball graphs and develop algorithms to find exact...
Polymer state approximations of Schroedinger wave functions
Klaus Fredenhagen; Felix Reszewski
2006-08-25T23:59:59.000Z
It is shown how states of a quantum mechanical particle in the Schroedinger representation can be approximated by states in the so-called polymer representation. The result may shed some light on the semiclassical limit of loop quantum gravity.
A fresh look at the adhesion approximation
Thomas Buchert
1997-11-04T23:59:59.000Z
I report on a systematic derivation of the phenomenological ``adhesion approximation'' from gravitational instability together with a brief evaluation of the related status of analytical modeling of large-scale structure.
Linear source approximation in CASMO5
Ferrer, R.; Rhodes, J. [Studsvik Scandpower, Inc., 504 Shoup Ave., Idaho Falls, ID 83402 (United States); Smith, K. [Dept. of Nuclear Science and Engineering, Massachusetts Inst. of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
2012-07-01T23:59:59.000Z
A Linear Source (LS) approximation has been implemented in the two-dimensional Method of Characteristics (MOC) transport solver in a prototype version of CASMO5. The LS approximation, which relies on the computation of trajectory-based spatial moments over source regions to obtain the linear source expansion coefficients, improves the solution accuracy relative to the 'flat' or constant source approximation. In addition, the LS formulation is capable of treating arbitrarily-shaped source regions and is compatible with standard Coarse-Mesh Finite Difference (CMFD) acceleration. Numerical tests presented in this paper for the C5G7 MOX benchmark show that, for comparable accuracy with respect to the reference solution, the LS approximation can reduce the run time by a factor of four and the memory requirements by a factor often relative to the FS scheme. (authors)
Approximate inference in Gaussian graphical models
Malioutov, Dmitry M., 1981-
2008-01-01T23:59:59.000Z
The focus of this thesis is approximate inference in Gaussian graphical models. A graphical model is a family of probability distributions in which the structure of interactions among the random variables is captured by a ...
Harmonic Wavelet Transform and Image Approximation
Zhang, Zhihua; Saito, Naoki
2010-01-01T23:59:59.000Z
DOI 10.1007/s10851-010-0202-x Harmonic Wavelet Transform andwe approximate f by a harmonic function u such that thebanks. We call this the Harmonic Wavelet Transform (HWT).
Schultis, J., Kenneth; Fenton, Donald, L.
2006-10-20T23:59:59.000Z
Increasing demand for energy necessitates nuclear power units to increase power limits. This implies significant changes in the design of the core of the nuclear power units, therefore providing better performance and safety in operations. A major hindrance to the increase of nuclear reactor performance especially in Pressurized Deionized water Reactors (PWR) is Axial Offset Anomaly (AOA)--the unexpected change in the core axial power distribution during operation from the predicted distribution. This problem is thought to be occur because of precipitation and deposition of lithiated compounds like boric acid (H{sub 2}BO{sub 3}) and lithium metaborate (LiBO{sub 2}) on the fuel rod cladding. Deposited boron absorbs neutrons thereby affecting the total power distribution inside the reactor. AOA is thought to occur when there is sufficient build-up of crud deposits on the cladding during subcooled nucleate boiling. Predicting AOA is difficult as there is very little information regarding the heat and mass transfer during subcooled nucleate boiling. An experimental investigation was conducted to study the heat transfer characteristics during subcooled nucleate boiling at prototypical PWR conditions. Pool boiling tests were conducted with varying concentrations of lithium metaborate (LiBO{sub 2}) and boric acid (H{sub 2}BO{sub 3}) solutions in deionized water. The experimental data collected includes the effect of coolant concentration, subcooling, system pressure and heat flux on pool the boiling heat transfer coefficient. The analysis of particulate deposits formed on the fuel cladding surface during subcooled nucleate boiling was also performed. The results indicate that the pool boiling heat transfer coefficient degrades in the presence of boric acid and lithium metaborate compared to pure deionized water due to lesser nucleation. The pool boiling heat transfer coefficients decreased by about 24% for 5000 ppm concentrated boric acid solution and by 27% for 5000 ppm lithium metaborate solution respectively at the saturation temperature for 1000 psi (68.9 bar) coolant pressure. Boiling tests also revealed the formation of fine deposits of boron and lithium on the cladding surface which degraded the heat transfer rates. The boron and lithium metaborate precipitates after a 5 day test at 5000 ppm concentration and 1000 psi (68.9 bar) operating pressure reduced the heat transfer rate 21% and 30%, respectively for the two solutions.
Range Condition: Key to Sustained Ranch Productivity
McGinty, Allan; White, Larry D.
2000-04-25T23:59:59.000Z
Range condition, or a rangeland's "state of health," is an ecological measurement of the current condition of a range. Range condition is evaluated by the plant species composition. This leaflet explains the importance of range condition, how range...
Formalising the Slow-Roll Approximation in Inflation
Andrew R. Liddle; Paul Parsons; John D. Barrow
1994-08-04T23:59:59.000Z
The meaning of the inflationary slow-roll approximation is formalised. Comparisons are made between an approach based on the Hamilton-Jacobi equations, governing the evolution of the Hubble parameter, and the usual scenario based on the evolution of the potential energy density. The vital role of the inflationary attractor solution is emphasised, and some of its properties described. We propose a new measure of inflation, based upon contraction of the comoving Hubble length as opposed to the usual e-foldings of physical expansion, and derive relevant formulae. We introduce an infinite hierarchy of slow-roll parameters, and show that only a finite number of them are required to produce results to a given order. The extension of the slow-roll approximation into an analytic slow-roll expansion, converging on the exact solution, is provided. Its role in calculations of inflationary dynamics is discussed. We explore rational-approximants as a method of extending the range of convergence of the slow-roll expansion up to, and beyond, the end of inflation.
Pacific Southwest Forest and Range
Standiford, Richard B.
. MCKETTA is an economist with the College of Forestry, Wildlife, and Range Sciences, University of Idaho has been developed for determining the cost of Fire Management Inputs (FMls)-the direct frreline costs, economic costs, fire economics, suppression costs, Fire Economics Evaluation System (FEES
Not Available
1994-07-01T23:59:59.000Z
This safety evaluation report (SER) documents the technical review of the US Advanced Boiling Water Reactor (ABWR) standard design by the US Nuclear Regulatory Commission (NRC) staff. The application for the ABWR design was initially submitted by the General Electric Company, now GE Nuclear Energy (GE), in accordance with the procedures of Appendix O of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50). Later GE requested that its application be considered as an application for design approval and subsequent design certification pursuant to 10 CFR {section} 52.45. The ABWR is a single-cycle, forced-circulation, boiling water reactor (BWR) with a rated power of 3,926 megawatts thermal (MWt) and a design power of 4,005 MWt. To the extent feasible and appropriate, the staff relied on earlier reviews for those ABWR design features that are substantially the same as those previously considered. Unique features of the ABWR design include internal recirculation pumps, fine-motion control rod drives, microprocessor-based digital logic and control systems, and digital safety systems. On the basis of its evaluation and independent analyses, the NRC staff concludes that, subject to satisfactory resolution of the confirmatory items identified in Section 1.8 of this SER, GE`s application for design certification meets the requirements of Subpart B of 10 CFR Part 52 that are applicable and technically relevant to the US ABWR standard design.
Not Available
1994-07-01T23:59:59.000Z
This safety evaluation report (SER) documents the technical review of the US Advanced Boiling Water Reactor (ABWR) standard design by the US Nuclear Regulatory Commission (NRC) staff. The application for the ABWR design was initially submitted by the General Electric Company, now GE Nuclear Energy (GE), in accordance with the procedures of Appendix O of Part 50 of Title 10 of the code of Federal Regulations (10 CFR Part 50). Later GE requested that its application be considered as an application for design approval and subsequent design certification pursuant to 10 CFR {section} 52.45. The ABWR is a single-cycle, forced-circulation, boiling water reactor (BWR) with a rated power of 3,926 megawatts thermal (MWt) and a design power of 4,005 MWt. To the extent feasible and appropriate, the staff relied on earlier reviews for those ABWR design features that are substantially the same as those previously considered. Unique features of the ABWR design include internal recirculation pumps, fine-motion control rod drives, microprocessor-based digital logic and control systems, and digital safety systems. On the basis of its evaluation and independent analyses, the NRC staff concludes that, subject to satisfactory resolution of the confirmatory items identified in Section 1.8 of this SER, GE`s application for design certification meets the requirements of Subpart B of 10 CFR Part 52 that are applicable and technically relevant to the US ABWR standard design.
Approximate Killing Fields as an Eigenvalue Problem
Christopher Beetle
2008-08-12T23:59:59.000Z
Approximate Killing vector fields are expected to help define physically meaningful spins for non-symmetric black holes in general relativity. However, it is not obvious how such fields should be defined geometrically. This paper relates a definition suggested recently by Cook and Whiting to an older proposal by Matzner, which seems to have been overlooked in the recent literature. It also describes how to calculate approximate Killing fields based on these proposals using an efficient scheme that could be of immediate practical use in numerical relativity.
Extending the Eikonal Approximation to Low Energy
Pierre Capel; Tokuro Fukui; Kazuyuki Ogata
2014-11-21T23:59:59.000Z
E-CDCC and DEA, two eikonal-based reaction models are compared to CDCC at low energy (e.g. 20AMeV) to study their behaviour in the regime at which the eikonal approximation is supposed to fail. We confirm that these models lack the Coulomb deflection of the projectile by the target. We show that a hybrid model, built on the CDCC framework at low angular momenta and the eikonal approximation at larger angular momenta gives a perfect agreement with CDCC. An empirical shift in impact parameter can also be used reliably to simulate this missing Coulomb deflection.
Realizing Physical Approximation of the Partial Transpose
Hyang-Tag Lim; Yong-Su Kim; Young-Sik Ra; Joonwoo Bae; Yoon-Ho Kim
2011-04-18T23:59:59.000Z
The partial transpose by which a subsystem's quantum state is solely transposed is of unique importance in quantum information processing from both fundamental and practical point of view. In this work, we present a practical scheme to realize a physical approximation to the partial transpose using local measurements on individual quantum systems and classical communication. We then report its linear optical realization and show that the scheme works with no dependence on local basis of given quantum states. A proof-of-principle demonstration of entanglement detection using the physical approximation of the partial transpose is also reported.
Approximate initial data for binary black holes
Kenneth A. Dennison; Thomas W. Baumgarte; Harald P. Pfeiffer
2006-08-26T23:59:59.000Z
We construct approximate analytical solutions to the constraint equations of general relativity for binary black holes of arbitrary mass ratio in quasicircular orbit. We adopt the puncture method to solve the constraint equations in the transverse-traceless decomposition and consider perturbations of Schwarzschild black holes caused by boosts and the presence of a binary companion. A superposition of these two perturbations then yields approximate, but fully analytic binary black hole initial data that are accurate to first order in the inverse of the binary separation and the square of the black holes' momenta.
Yoder, G. L.; Morris, D. G.; Mullins, C. B.; Ott, L. J.; Reed, D. A.
1982-03-01T23:59:59.000Z
Assessment of six film boiling correlations and one single-phase vapor correlation has been made using data from 22 steady state upflow rod bundle tests (series 3.07.9). Bundle fluid conditions were calculated using energy and mass conservation considerations. Results of the steady state film boiling tests support the conclusions reached in the analysis of prior transient tests 3.03.6AR, 3.06.6B, and 3.08.6C. Comparisons between experimentally determined and correlation-predicted heat transfer coefficients, are presented.
Range gated strip proximity sensor
McEwan, T.E.
1996-12-03T23:59:59.000Z
A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.
Range gated strip proximity sensor
McEwan, Thomas E. (Livermore, CA)
1996-01-01T23:59:59.000Z
A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.
Blind Channel Equalization and -Approximation Algorithms
Ye, Yinyu
Blind Channel Equalization and #15;-Approximation Algorithms #3; Qingyu Li 1 , Er-Wei Bai 1 University of Iowa Iowa City, IA 52242 Abstract In this paper, we show that a blind equalizer can be obtained without using any sta- tistical information on the input by formulating the blind channel equalization
FRACTAL APPROXIMATION AND COMPRESSION USING PROJECTED IFS
Baskurt, Atilla
FRACTAL APPROXIMATION AND COMPRESSION USING PROJECTED IFS Ă?ric GuĂ©rin, Ă?ric Tosan and Atilla, or images) with fractal models is an important center of interest for research. The general inverse problem.The most known of them is the fractal image compression method introduced by Jacquin. Generally speaking
Approximate Inference and Protein-Folding
Weiss, Yair
Approximate Inference and Protein-Folding Chen Yanover and Yair Weiss School of Computer Science Side-chain prediction is an important subtask in the protein-folding problem. We show that #12;nding algorithms, including a widely used protein-folding software (SCWRL). 1 Introduction Inference in graphical
APPROXIMATION ALGORITHMS FOR SCHEDULING a dissertation
Chekuri, Chandra
Approved for the University Committee on Graduate Studies: iii #12; iv #12; Abstract This thesis describes instance of the problem, returns a solution whose value is within some guaranteed multiplicative factor ff release dates only we obtain an e e\\Gamma1 ' 1:58 approximation. For the parallel machine case we obtain
Polynomial Approximations for Continuous Linear Programs
2012-04-05T23:59:59.000Z
where the cost rate c(t), the right hand side vector b(t) as well as the matrices. G(t) and H(t, ... dual approximations, respectively, estimates the degree of suboptimality of the ...... the matrix of capital coefficients, where Bij defines the stock of good i required per unit of ...... In Optimization methods for resource allocation (Proc.
Symbolic Test Selection Based on Approximate Analysis
Paris-Sud XI, Université de
Symbolic Test Selection Based on Approximate Analysis Bertrand Jeannet, Thierry J´eron, Vlad Rusu}@irisa.fr Abstract. This paper addresses the problem of generating symbolic test cases for testing the conformance. The challenge we consider is the selection of test cases according to a test purpose, which is here a set
Approximating Power Indices --Theoretical and Empirical Analysis
Rosenschein, Jeff
, by providing lower bounds for both deter- ministic and randomized algorithms for calculating power indices. WeApproximating Power Indices -- Theoretical and Empirical Analysis Yoram Bachrach School and Computer Science, The Hebrew University, Jerusalem, Israel Amin Saberi Department of Management Science
Kirchhoff approximation for diffusive waves Jorge Ripoll*
Lorenzo, Jorge Ripoll
Laboratoire d'Energetique Moleculaire et Macroscopique, Combustion, Ecole Centrale Paris, Centre National de for accurately solving the direct scattering problem 17,18,23 for arbitrary geometries, but these methods,26 . This approximation is a linear method that does not involve matrix inversion while solving the forward problem
IMPROVING THE APPROXIMATION AND CONVERGENCE CAPABILITIES OF
Yeung, Dit-Yan
Âdimensional data. Projection pursuit learning (PPL) formulates PPR in a neural network framework. One major difference between PPR and PPL is that the smoothers in PPR are nonparametric, whereas those in PPL are based known, we demonstrate that PPL networks do not have the universal approximation and strong convergence
Approximating Human Reaching Volumes Using Inverse Kinematics
Rodríguez, Inmaculada
of reach: standing reach, which is useful in computer animation where virtual humans have to interact. Introduction Virtual Humans are a valuable medium for gaining knowledge and understanding about the human bodyApproximating Human Reaching Volumes Using Inverse Kinematics I. Rodrígueza , M. Peinadoa , R
Extended-range tiltable micromirror
Allen, James J. (Albuquerque, NM); Wiens, Gloria J. (Newberry, FL); Bronson, Jessica R. (Gainesville, FL)
2009-05-05T23:59:59.000Z
A tiltable micromirror device is disclosed in which a micromirror is suspended by a progressive linkage with an electrostatic actuator (e.g. a vertical comb actuator or a capacitive plate electrostatic actuator) being located beneath the micromirror. The progressive linkage includes a pair of torsion springs which are connected together to operate similar to a four-bar linkage with spring joints. The progressive linkage provides a non-linear spring constant which can allow the micromirror to be tilted at any angle within its range substantially free from any electrostatic instability or hysteretic behavior.
Range Fuels | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit with form History Facebook iconQuito,Jump to:Radiant ElectricRamkyRange Fuels
Orthogonal Polynomial Approximation in Higher Dimensions: Applications in Astrodynamics
Bani Younes, Ahmad H.
2013-08-05T23:59:59.000Z
harmonic series by a family of locally precise orthogonal polynomial approximations for efficient computation. A method is introduced which adapts the approximation degree radially, compatible with the truth that the highest degree approximations (to...
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS
Tzavaras, Athanasios E.
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS deal with the approximation of conservation * *laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discu
Winckler, Gisela
PII S0016-7037(99)00441-X Sub sea floor boiling of Red Sea Brines: New indication from noble gas in revised form December 8, 1999) Abstract--Hydrothermal brines from the Atlantis II Deep, Red Sea, have been depressions filled by highly saline brines (Hartmann et al., 1998a). The Atlantis II Deep, located
Banerjee, Debjyoti
with embedded cartridge heaters and K-type thermocouples. De-ion- ized (DI) water was used as the test fluidFlow boiling enhancement on a horizontal heater using carbon nanotube coatings N. Singh, V flux on a horizontal heater that is heated from below. The horizontal heater consists of either a bare
NONE
1993-09-15T23:59:59.000Z
This report contains an extensive evaluation of GE advanced boiling water reactor plants prepared for United State Department of Energy. The general areas covered in this report are: core and system performance; fuel cycle; infrastructure and deployment; and safety and environmental approval.
Ahn, Hee Seok
2007-09-17T23:59:59.000Z
boiling on nano-structured surfaces. Experiments were conducted with three horizontal silicon surfaces, two of which were coated with vertically aligned multi-walled carbon nanotubes (MWCNT) with heights of 9 and 25 Ă?Âąm, respectively, and diameters...
A numerical approximation to distribution function
Tuttle, Keith Allan
1977-01-01T23:59:59.000Z
then is to approximate F(Y) numerically. We sub- divide the unit cube Q into N cubes eqch of length h I/N on a n n side. Within each individual subcube Q , we will define an affine approximation to f, W = g(x , . . . , x ), which requires the gradient of 1' ' 'n our... & h/2, k k i + 1/2 2 n k k = 1, 2, . . . , n]. Let f(x) f C [Q ] the space of twice continuously n differentiable functions on Q , and define the auxiliary function g(x) as the tangent to f at x. i + 1 2 for x f Q. . That is, if x I Q i (x) f (x1 2...
Compressed Indexes for Approximate String Matching
Sung, Wing-Kin Ken"
Compressed Indexes for Approximate String Matching Ho-Leung Chan1 Tak-Wah Lam1, Wing-Kin Sung2 Siu the index space to O(n log n). Huynh et al. [10] and Lam et al. [11] further compressed the index to O,wongss}@comp.nus.edu.sg Abstract. We revisit the problem of indexing a string S[1..n] to support searching all substrings
Approximating spheroid inductive responses using spheres
Smith, J. Torquil; Morrison, H. Frank
2003-12-12T23:59:59.000Z
The response of high permeability ({mu}{sub r} {ge} 50) conductive spheroids of moderate aspect ratios (0.25 to 4) to excitation by uniform magnetic fields in the axial or transverse directions is approximated by the response of spheres of appropriate diameters, of the same conductivity and permeability, with magnitude rescaled based on the differing volumes, D.C. magnetizations, and high frequency limit responses of the spheres and modeled spheroids.
BLOCK DIAGONALLY DOMINANT POSITIVE DEFINITE APPROXIMATE FILTERS AND SMOOTHERS
BLOCK DIAGONALLY DOMINANT POSITIVE DEFINITE APPROXIMATE FILTERS AND SMOOTHERS Running title: BLOCKĆciently small as to preclude the loss of positive de#12;niteness in the approximate equations. Therefore
BLOCK DIAGONALLY DOMINANT POSITIVE DEFINITE APPROXIMATE FILTERS AND SMOOTHERS
BLOCK DIAGONALLY DOMINANT POSITIVE DEFINITE APPROXIMATE FILTERS AND SMOOTHERS Running title: BLOCK the loss of positive definiteness in the approximate equations. Therefore previous analyses have
Gauntt, R.O.; Gasser, R.D.; Fryer, C.P.; Walker, J.V.
1988-01-01T23:59:59.000Z
The DF-4 in-pile fuel damage experiment, one of a series of tests performed as part of the USNRC's internationally sponsored severe fuel damage (SFD) program, and carried out at Sandia National Laboratories, addressed the behavior of boiling water reactor (BWR) fuel canisters and control blades in the high temperature environment of an unrecovered loss of coolant accident. The DF-4 test is described in some detail herein and results from the experiment are presented. Significant results from prior experiments in the series are also summarized. Important findings from the DF-4 test include the low temperature melting of the stainless steel control blade caused by reaction with the B/sub 4/C, and the subsequent low temperature attack of the Zr-4 channel box by the relocating molten blade components. This early melt and relocation phenomena could significantly influence the progression of meltdown in BWRs and should be considered in SFD accident analyses. 14 refs., 9 figs.
S.T. Revankar; W. Zhou; Gavin Henderson
2008-07-08T23:59:59.000Z
The main goal of the project was to study analytically and experimentally the condensation heat transfer for the passive condenser system such as GE Economic Simplified Boiling Water Reactor (ESBWR). The effect of noncondensable gas in condenser tube and the reduction of secondary pool water level to the condensation heat transfer coefficient was the main focus in this research. The objectives of this research were to : 1) obtain experimental data on the local and tube averaged condensation heat transfer rates for the PCCS with non-condensable and with change in the secondary pool water, 2) assess the RELAP5 and TRACE computer code against the experimental data, and 3) develop mathematical model and ehat transfer correlation for the condensation phenomena for system code application. The project involves experimentation, theoretical model development and verification, and thermal- hydraulic codes assessment.
McCormack, K.E.; Gallaher, R.B.
1982-03-01T23:59:59.000Z
This document presents a bibliography that contains 100-word abstracts of event reports submitted to the US Nuclear Regulatory Commission concerning operational events that occurred at boiling-water-reactor nuclear power plants in 1980. The 1547 abstracts included on microfiche in this bibliography describe incidents, failures, and design or construction deficiencies that were experienced at the facilities. These abstracts are arranged alphabetically by reactor name and then chronologically for each reactor. Full-size keyword and permuted-title indexes to facilitate location of individual abstracts are provided following the text. Tables that summarize the information contained in the bibliography are also provided. The information in the tables includes a listing of the equipment items involved in the reported events and the associated number of reports for each item. Similar information is given for the various kinds of instrumentation and systems, causes of failures, deficiencies noted, and the time of occurrence (i.e., during refueling, operation, testing, or construction).
New flow boiling heat transfer correlation for CFC-114 and C{sub 4}F{sub 10}
Szady, A.J. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.
1995-08-01T23:59:59.000Z
The flow boiling tests being conducted at Cudo Technologies, Ltd. in Lexington, Kentucky are a part of The GDP Coolant Replacement Project. The tests are to be done with two alternates, C{sub 4}F{sub 10} and C{sub 4}F{sub 8}, as well as CFC-114. So far, tests were conducted with CFC-114 and C{sub 4}F{sub 10}. The CFC-114 data by Cudo shows better heat transfer performance than that predicted by the codes used in the numerical model which were based on a superposition model. The data was applied to an asymptotic model developed by Steiner and Taborek. The new correlation developed seems to fit better with the Cudo data as well as the Paducah cell test data. The model will be further investigated when C{sub 4}F{sub 8} data is available.
Extended Soft Binding Mean Spherical- Contact Probability Approximation for Hard Ions
Blum, L. [Department of Mathematics, Rutgers University (United States); Arias, M.; Veloz, D. V. Perez [Physics Department, University of Puerto Rico (Puerto Rico)
2009-03-09T23:59:59.000Z
We propose a new analytical theory of electrolytes that extends the range of the Mean Spherical Approximation (MSA) to include extremely high charges [1, 2, 3, 4, 5]. In the MSA the thermodynamics and structure of the most general electrolyte are given in terms of a single screening parameter {gamma}, [1] which is obtained from the simple algebraic equation.
MSci Project 20142015 Dr Myrta Gruning Efficient diagonalisation of large Random-Phase Approximation
Paxton, Anthony T.
larger and more complex systems of interest for several applications, ranging from photovoltaics to art of non-Hermitian matrices, the Random-Phase Approx- imation (RPA) matrices. The size of those matrices matrix. However, such an approximation has been showed to breakdown for systems such as nanotubes
Rust, K.R.; Wilson, J.M.
1992-06-01T23:59:59.000Z
The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.
Relativistic Random Phase Approximation At Finite Temperature
Niu, Y. F. [State Key Laboratory for Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Physics Department, Faculty of Science, University of Zagreb (Croatia); Paar, N.; Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb (Croatia); Meng, J. [State Key Laboratory for Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)
2009-08-26T23:59:59.000Z
The fully self-consistent finite temperature relativistic random phase approximation (FTRRPA) has been established in the single-nucleon basis of the temperature dependent Dirac-Hartree model (FTDH) based on effective Lagrangian with density dependent meson-nucleon couplings. Illustrative calculations in the FTRRPA framework show the evolution of multipole responses of {sup 132}Sn with temperature. With increased temperature, in both monopole and dipole strength distributions additional transitions appear in the low energy region due to the new opened particle-particle and hole-hole transition channels.
Entangled games are hard to approximate
Julia Kempe; Hirotada Kobayashi; Keiji Matsumoto; Ben Toner; Thomas Vidick
2007-11-21T23:59:59.000Z
We establish the first hardness results for the problem of computing the value of one-round games played by a verifier and a team of provers who can share quantum entanglement. In particular, we show that it is NP-hard to approximate within an inverse polynomial the value of a one-round game with (i) quantum verifier and two entangled provers or (ii) classical verifier and three entangled provers. Previously it was not even known if computing the value exactly is NP-hard. We also describe a mathematical conjecture, which, if true, would imply hardness of approximation to within a constant. We start our proof by describing two ways to modify classical multi-prover games to make them resistant to entangled provers. We then show that a strategy for the modified game that uses entanglement can be ``rounded'' to one that does not. The results then follow from classical inapproximability bounds. Our work implies that, unless P=NP, the values of entangled-prover games cannot be computed by semidefinite programs that are polynomial in the size of the verifier's system, a method that has been successful for more restricted quantum games.
APPROXIMATE DYNAMIC PROGRAMMING--II: ALGORITHMS
Powell, Warren B.
. These problems range from relatively low-dimensional applications to very high- dimensional industrial problems of uncertainty. A short list of applications, which illustrate different prob- lem classes, include the following of Go. Â· Controlling a Device. This might be a robot or unmanned aerial vehicle, but there is a need
Approximate Dynamic Programming -II: Warren B. Powell
Powell, Warren B.
, recently, the Chinese game of Go. Â· Controlling a device - This might be a robot or unmanned aerial vehicle, but there is a need for autonomous devices to manage themselves for tasks ranging from vacuuming the floor are managing blood inventories, financial portfolios or fleets of vehicles, we often have to move, transform
Modeling, Analysis and Numerical Approximations of Image ...
... fields, which have a broad range of applications in science, engineering and industry. Not long ago, statistical and ad hoc methods had been main tools for studying and analyzing image processing and computer vision problems. ... interesting and challenging mathematical problems in the areas of Calculus of Variation, ...
Radar range measurements in the atmosphere.
Doerry, Armin Walter
2013-02-01T23:59:59.000Z
The earth's atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.
Lead exposure at uncovered outdoor firing ranges
Goldberg, R.L.; Hicks, A.M.; O'Leary, L.M.; London, S. (University of Southern California School of Medicine, Los Angeles (USA))
1991-06-01T23:59:59.000Z
Excessive lead exposure in shooting instructors at indoor firing ranges and covered outdoor firing ranges has been documented. The City of Los Angeles assessed exposure of its full-time shooting instructors at uncovered outdoor ranges via air monitoring and blood lead-level measurements. Results of these tests revealed that significant lead exposure and absorption can occur at outdoor firing ranges. The use of copper-jacketed ammunition may decrease air lead levels and decrease lead absorption by range instructors.
On the approximations of the distribution function of fusion alpha particles
Bilato, R., E-mail: roberto.bilato@ipp.mpg.de; Brambilla, M.; Poli, E. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)
2014-10-15T23:59:59.000Z
The solution of the drift-kinetic equation for fusion-born alpha particles is derived in the limit of dominant parallel streaming, and it is related to the usual slowing-down distribution function. The typical approximations of the fast tail of fusion-born alpha particles are briefly compared and discussed. In particular, approximating the distribution function of fast-alpha particles with an “equivalent” Maxwellian is inaccurate to describe absorption of radio-frequency waves in the ion-cyclotron range of frequencies.
Source term attenuation by water in the Mark I boiling water reactor drywell
Powers, D.A. [Sandia National Labs., Albuquerque, NM (United States)
1993-09-01T23:59:59.000Z
Mechanistic models of aerosol decontamination by an overlying water pool during core debris/concrete interactions and spray removal of aerosols from a Mark I drywell atmosphere are developed. Eighteen uncertain features of the pool decontamination model and 19 uncertain features of the model for the rate coefficient of spray removal of aerosols are identified. Ranges for values of parameters that characterize these uncertain features of the models are established. Probability density functions for values within these ranges are assigned according to a set of rules. A Monte Carlo uncertainty analysis of the decontamination factor produced by water pools 30 and 50 cm deep and subcooled 0--70 K is performed. An uncertainty analysis for the rate constant of spray removal of aerosols is done for water fluxes of 0.25, 0.01, and 0.001 cm{sup 3} H{sub 2}O/cm{sup 2}-s and decontamination factors of 1.1, 2, 3.3, 10, 100, and 1000.
Short-range correlations and neutrinoless double beta decay
M. Kortelainen; O. Civitarese; J. Suhonen; J. Toivanen
2007-01-18T23:59:59.000Z
In this work we report on the effects of short-range correlations upon the matrix elements of neutrinoless double beta decay. We focus on the calculation of the matrix elements of the neutrino-mass mode of neutrinoless double beta decays of 48Ca and 76Ge. The nuclear-structure components of the calculation, that is the participant nuclear wave functions, have been calculated in the shell-model scheme for 48Ca and in the proton-neutron quasiparticle random-phase approximation (pnQRPA) scheme for 76Ge. We compare the traditional approach of using the Jastrow correlation function with the more complete scheme of the unitary correlation operator method (UCOM). Our results indicate that the Jastrow method vastly exaggerates the effects of short-range correlations on the neutrinoless double beta decay nuclear matrix elements.
Four-boson system with short-range interactions
Platter, L.; Hammer, H.-W.; Meissner, Ulf-G. [Forschungszentrum Juelich, Institut fuer Kernphysik, D-52425 Juelich (Germany); Helmholtz-Institut fuer Strahlen-und Kernphysik (Theorie), Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States); Helmholtz-Institut fuer Strahlen-und Kernphysik (Theorie), Universitaet Bonn, Nussallee 14-16, D-53115 Bonn, Germany and Forschungszentrum Juelich, Institut fuer Kernphysik, D-52425 Juelich (Germany)
2004-11-01T23:59:59.000Z
We consider the nonrelativistic four-boson system with short-range forces and large scattering length in an effective quantum mechanics approach. We construct the effective interaction potential at leading order in the large scattering length and compute the four-body binding energies using the Yakubovsky equations. Cutoff independence of the four-body binding energies does not require the introduction of a four-body force. This suggests that two- and three-body interactions are sufficient to renormalize the four-body system. We apply the equations to {sup 4}He atoms and calculate the binding energy of the {sup 4}He tetramer. We observe a correlation between the trimer and tetramer binding energies similar to the Tjon line in nuclear physics. Over the range of binding energies relevant to {sup 4}He atoms, the correlation is approximately linear.
Eikonal approximation in the theory of energy loss by fast charged particles
Matveev, V. I., E-mail: matveev.victor@pomorsu.ru; Makarov, D. N.; Gusarevich, E. S. [Lomonosov Pomor State University (Russian Federation)
2011-05-15T23:59:59.000Z
Energy losses in fast charged particles as a result of collisions with atoms are considered in the eikonal approximation. It is shown that the nonperturbative contribution to effective stopping in the range of intermediate impact parameters (comparable with the characteristic sizes of the electron shells of the target atoms) may turn out to be significant as compared to shell corrections to the Bethe-Bloch formula calculated in perturbation theory. The simplifying assumptions are formulated under which the Bethe-Bloch formula can be derived in the eikonal approximation. It is shown that the allowance for nonperturbative effects may lead to considerable (up to 50%) corrections to the Bethe-Bloch formula. The applicability range for the Bethe-Bloch formula is analyzed. It is concluded that calculation of the energy loss in the eikonal approximation (in the range of impact parameters for which the Bethe-Bloch formula is normally used) is much more advantageous than analysis based on the Bethe-Bloch formula and its modifications because not only the Bloch correction is included in the former calculations, the range of intermediate impact parameters is also taken into account nonperturbatively; in addition, direct generalization to the cases of collisions of complex projectiles and targets is possible in this case.
Boiling the Vacuum with an X-Ray Free Electron Laser
A. Ringwald
2003-04-15T23:59:59.000Z
X-ray free electron lasers will be constructed in this decade, both at SLAC in the form of the so-called Linac Coherent Light Source as well as at DESY, where the so-called TESLA XFEL laboratory uses techniques developed for the design of the TeV energy superconducting electron-positron linear accelerator TESLA. Such X-ray lasers may allow also for high-field science applications by exploiting the possibility to focus their beams to a spot with a small radius, hopefully in the range of the laser wavelength. Along this route one obtains very large electric fields, much larger than those obtainable with any optical laser of the same power. We consider here the possibility of obtaining an electric field so high that electron-positron pairs are spontaneously produced in vacuum (Schwinger pair production) and review the prospects to verify this non-perturbative production mechanism for the first time in the laboratory.
Approximate Weighted Matching On Emerging Manycore and Multithreaded Architectures
Halappanavar, Mahantesh; Feo, John T.; Villa, Oreste; Tumeo, Antonino; Pothen, Alex
2012-11-30T23:59:59.000Z
Graph matching is a prototypical combinatorial problem with many applications in computer science and scientific computing, but algorithms for computing optimal matchings are challenging to parallelize. Approximate matching algorithms provide an alternate route for parallelization, and in many contexts compute near-optimal matchings for large-scale graphs. We present sharedmemory parallel implementations for computing half-approximate weighted matching on state-of-the-art multicore (Intel Nehalem and AMD Magny-Cours), manycore (Nvidia Tesla and Nvidia Fermi) and massively multithreaded (Cray XMT) platforms. We provide two implementations: the first implementation uses shared work queues, and is suited to all these platforms; the second implementation is based on dataflow principles, and exploits the architectural features of the Cray XMT. Using a carefully chosen dataset that exhibits characteristics from a wide range of real-world applications, we show scalable performance across different platforms. In particular, for one instance of the input, an R-MAT graph (RMAT-G), we show speedups of: about 32 on 48 cores of an AMD Magny-Cours; 7 on 8 cores of Intel Nehalem; 3 on Nvidia Tesla and 10 on Nvidia Fermi relative to one core of Intel Nehalem; and 60 on 128 processors of Cray XMT. We demonstrate good weak and strong scaling for graphs with up to a billion edges using up to 12, 800 threads. Given the breadth of this work, we focus on simplicity and portability of software rather than excessive fine-tuning for each platform. To the best of our knowledge, this is the first such large-scale study of the half-approximate weighted matching problem on shared-memory platforms. Driven by the critical enabling role of combinatorial algorithms such as matching in scientific computing and the emergence of informatics applications, there is a growing demand to support irregular computations on current and future computing platforms. In this context, we evaluate the capability of emerging multithreaded platforms to tolerate latency induced by irregular memory access patterns, and to support fine-grained parallelism via light-weight synchronization mechanisms. By contrasting the architectural features of these platforms against the Cray XMT, which is specifically designed to support irregular memory-intensive applications, we delineate the impact of these choices on performance.
American Society for Testing and Materials. Philadelphia
2000-01-01T23:59:59.000Z
1.1 This test method describes a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25% (by mass ) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested. 1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing using this sodium chloride test method. 1.3 This boiling sodium chloride test method was used in an interlaboratory test program to evaluate wrought stainless steels, including duplex (ferrite-austenite) stainless and an alloy with up to about 33% nickel. It may also b...
NONE
1997-05-01T23:59:59.000Z
This report supplements the final safety evaluation report (FSER) for the US Advanced Boiling Water Reactor (ABWR) standard design. The FSER was issued by the US Nuclear Regulatory Commission (NRC) staff as NUREG-1503 in July 1994 to document the NRC staff`s review of the US ABWR design. The US ABWR design was submitted by GE Nuclear Energy (GE) in accordance with the procedures of Subpart B to Part 52 of Title 10 of the Code of Federal Regulations. This supplement documents the NRC staff`s review of the changes to the US ABWR design documentation since the issuance of the FSER. GE made these changes primarily as a result of first-of-a-kind-engineering (FOAKE) and as a result of the design certification rulemaking for the ABWR design. On the basis of its evaluations, the NRC staff concludes that the confirmatory issues in NUREG-1503 are resolved, that the changes to the ABWR design documentation are acceptable, and that GE`s application for design certification meets the requirements of Subpart B to 10 CFR Part 52 that are applicable and technically relevant to the US ABWR design.
Hoshino, T.; Shirakawa, T.
1982-03-01T23:59:59.000Z
The three-dimensional boiling water reactor (BWR) core following the daily load was simulated by the use of the processor array for continuum simulation (PACS-32), a newly developed parallel microprocessor system. The PACS system consists of 32 processing units (PUs) (microprocessors) and has a multiinstruction, multidata type architecture, being optimum to the numerical simulation of the partial differential equations. The BWR core model includes the modified twogroup finite difference, coarse-mesh model for neutronics, steady-state model for thermohydraulics, criticality control by core coolant flow, and the time-dependent solution of iodine-xenon dynamics with constant flux level. The analysis of the parallel processing program revealed that the overhead is independent from the number of PUs and that the efficiency of PUs, i.e., the ratio of effective calculation over total, amounts to 75%, even up to 90% if it is limited to the core part. Simulation was made on the daily load follow for 144 h including the weekend, which took 1.3 central processing unit hours by the PACS system. The PACS system demonstrated a computation speed nearly one-tenth that of the large-scale high-speed general purpose computer, with a 25 times better cost performance ratio and showed that the system could be used as the pratical BWR core simulator with more complicated core models.
Not Available
1993-05-13T23:59:59.000Z
Timely disposal of the weapons plutonium is of paramount importance to permanently safeguarding this material. GE`s 1300 MWe Advanced Boiling Water Reactor (ABWR) has been designed to utilize fill] core loading of mixed uranium-plutonium oxide fuel. Because of its large core size, a single ABWR reactor is capable of disposing 100 metric tons of plutonium within 15 years of project inception in the spiking mode. The same amount of material could be disposed of in 25 years after the start of the project as spent fuel, again using a single reactor, while operating at 75 percent capacity factor. In either case, the design permits reuse of the stored spent fuel assemblies for electrical energy generation for the remaining life of the plant for another 40 years. Up to 40 percent of the initial plutonium can also be completely destroyed using ABWRS, without reprocessing, either by utilizing six ABWRs over 25 years or by expanding the disposition time to 60 years, the design life of the plants and using two ABWRS. More complete destruction would require the development and testing of a plutonium-base fuel with a non-fertile matrix for an ABWR or use of an Advanced Liquid Metal Reactor (ALMR). The ABWR, in addition, is fully capable of meeting the tritium target production goals with already developed target technology.
Dykin, V.; Pazsit, I. [Chalmers Univ. of Technology, Div. of Nuclear Engineering, Dept. of Applied Physics, SE-412 96 Gothenburg (Sweden)
2012-07-01T23:59:59.000Z
A possibility to reconstruct the axial void profile from the simulated in-core neutron noise which is caused by density fluctuations in a Boiling Water Reactor (BWR) heated channel is considered. For this purpose, a self-contained model of the two-phase flow regime is constructed which has quantitatively and qualitatively similar properties to those observed in real BWRs. The model is subsequently used to simulate the signals of neutron detectors induced by the corresponding perturbations in the flow density. The bubbles are generated randomly in both space and time using Monte-Carlo techniques. The axial distribution of the bubble production is chosen such that the mean axial void fraction and void velocity follow the actual values of BWRs. The induced neutron noise signals are calculated and then processed by the standard signal analysis methods such as Auto-Power Spectral Density (APSD) and Cross-Power Spectral Density (CPSD). Two methods for axial void and velocity profiles reconstruction are discussed: the first one is based on the change of the break frequency of the neutron auto-power spectrum with axial core elevation, while the second refers to the estimation of transit times of propagating steam fluctuations between different axial detector positions. This paper summarizes the principles of the model and presents a numerical testing of the qualitative applicability to estimate the required parameters for the reconstruction of the void fraction profile from the neutron noise measurements. (authors)
Trianti, Nuri, E-mail: nuri.trianti@gmail.com, E-mail: szaki@fi.itba.c.id; Su'ud, Zaki, E-mail: nuri.trianti@gmail.com, E-mail: szaki@fi.itba.c.id; Arif, Idam, E-mail: nuri.trianti@gmail.com, E-mail: szaki@fi.itba.c.id [Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Science, Bandung Institute of Technology (Ganesha 10 Bandung, Indonesia) (Indonesia); Riyana, EkaSapta [Nuclear Energy Regulatory Agency (BAPETEN) (Indonesia)
2014-09-30T23:59:59.000Z
Neutronic performance of small long-life boiling water reactors (BWR) with thorium nitride based fuel has been performed. A recent study conducted on BWR in tight lattice environments (with a lower moderator percentage) produces small power reactor which has some specifications, i.e. 10 years operation time, power density of 19.1 watt/cc and maximum excess reactivity of about 4%. This excess reactivity value is smaller than standard reactivity of conventional BWR. The use of hexagonal geometry on the fuel cell of BWR provides a substantial effect on the criticality of the reactor to obtain a longer operating time. Supported by a tight concept lattice where the volume fraction of the fuel is greater than the moderator and fuel, Thorium Nitride give good results for fuel cell design on small long life BWR. The excess reactivity of the reactor can be reduced with the addition of gadolinium as burnable poisons. Therefore the hexagonal tight lattice fuel cell design of small long life BWR that has a criticality more than 20 years of operating time has been obtained.
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS
Tzavaras, Athanasios E.
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS Athanasios E. Tzavaras Abstract. These lecture notes deal with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation
Adaptive approximation of higher order posterior statistics
Lee, Wonjung, E-mail: leew@maths.ox.ac.uk
2014-02-01T23:59:59.000Z
Filtering is an approach for incorporating observed data into time-evolving systems. Instead of a family of Dirac delta masses that is widely used in Monte Carlo methods, we here use the Wiener chaos expansion for the parametrization of the conditioned probability distribution to solve the nonlinear filtering problem. The Wiener chaos expansion is not the best method for uncertainty propagation without observations. Nevertheless, the projection of the system variables in a fixed polynomial basis spanning the probability space might be a competitive representation in the presence of relatively frequent observations because the Wiener chaos approach not only leads to an accurate and efficient prediction for short time uncertainty quantification, but it also allows to apply several data assimilation methods that can be used to yield a better approximate filtering solution. The aim of the present paper is to investigate this hypothesis. We answer in the affirmative for the (stochastic) Lorenz-63 system based on numerical simulations in which the uncertainty quantification method and the data assimilation method are adaptively selected by whether the dynamics is driven by Brownian motion and the near-Gaussianity of the measure to be updated, respectively.
Regular Type III and Type N Approximate Solutions
Philip Downes; Paul MacAllevey; Bogdan Nita; Ivor Robinson
2001-05-18T23:59:59.000Z
New type III and type N approximate solutions which are regular in the linear approximation are shown to exist. For that, we use complex transformations on self-dual Robinson-Trautman metrics rather then the classical approach. The regularity criterion is the boundedness and vanishing at infinity of a scalar obtained by saturating the Bel-Robinson tensor of the first approximation by a time-like vector which is constant with respect to the zeroth approximation.
Optimization Online - Approximation of rank function and its ...
shujun Bi
2011-07-10T23:59:59.000Z
Jul 10, 2011 ... Particularly, with two families of approximation functions, we ... Citation: Department of Mathematics, South China University of Technology, ...
Viking Range: Order (2014-CE-23014)
Broader source: Energy.gov [DOE]
DOE ordered Viking Range, LLC to pay a $8,000 civil penalty after finding Viking Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.
American Range: Order (2014-CE-23006)
Broader source: Energy.gov [DOE]
DOE ordered American Range Corporation to pay a $8,000 civil penalty after finding American Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.
On Cartesian trees and range minimum queries
Demaine, Erik D.
We present new results on Cartesian trees with applications in range minimum queries and bottleneck edge queries. We introduce a cache-oblivious Cartesian tree for solving the range minimum query problem, a Cartesian tree ...
Range Fuels Commercial-Scale Biorefinery
Broader source: Energy.gov [DOE]
The Range Fuels commercial-scale biorefinery will use a variety of feedstocks to create cellulosic ethanol, methanol, and power.
BUILDING SURROGATE MODELS BASED ON DETAILED AND APPROXIMATE SIMULATIONS
Seepersad, Carolyn Conner
- Page 1 - BUILDING SURROGATE MODELS BASED ON DETAILED AND APPROXIMATE SIMULATIONS Zhiguang Qian is taken to integrate data from approximate and detailed simulations to build a surrogate model approximate simulations form the bulk of the data, and they are used to build a model based on a Gaussian
Smoluchowski-Kramers approximation in the case of variable friction
Mark Freidlin; Wenqing Hu
2012-03-03T23:59:59.000Z
We consider the small mass asymptotics (Smoluchowski-Kramers approximation) for the Langevin equation with a variable friction coefficient. The limit of the solution in the classical sense does not exist in this case. We study a modification of the Smoluchowski-Kramers approximation. Some applications of the Smoluchowski-Kramers approximation to problems with fast oscillating or discontinuous coefficients are considered.
Technical Note Variational free energy and the Laplace approximation
Daunizeau, Jean
Technical Note Variational free energy and the Laplace approximation Karl Friston,a, Jérémie October 2006 This note derives the variational free energy under the Laplace approximation, with a focus. This is relevant when using the free energy as an approximation to the log-evidence in Bayesian model averaging
Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws
Tzavaras, Athanasios E.
Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws Athanasios E with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discussed, as suggested by the second law
Modulated power-law behaviour in Stirling's approximation
Hatton, Les
Modulated power-law behaviour in Stirling's approximation Les Hatton CISM, University of Kingston. This argument used Stirling's approximation which limits its relevance to larger component sizes. Although power to broaden Stirling's approximation to see if it corresponds with the departures from power-law observed
Bond selective chemistry beyond the adiabatic approximation
Butler, L.J. [Univ. of Chicago, IL (United States)
1993-12-01T23:59:59.000Z
One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.
Tonopah Test Range capabilities: technical manual
Manhart, R.L.
1982-11-01T23:59:59.000Z
This manual describes Tonopah Test Range (TTR), defines its testing capabilities, and outlines the steps necessary to schedule tests on the Range. Operated by Sandia National Laboratories, TTR is a major test facility for DOE-funded weapon programs. The Range presents an integrated system for ballistic test vehicle tracking and data acquisition. Multiple radars, optical trackers, telemetry stations, a central computer complex, and combined landline/RF communications systems assure full Range coverage for any type of test. Range operations are conducted by a department within Sandia's Field Engineering Directorate. While the overall Range functions as a complete system, it is operationally divided into the Test Measurements, Instrumentation Development, and Range Operations divisions. The primary function of TTR is to support DOE weapons test activities. Management, however, encourages other Government agencies and their contractors to schedule tests on the Range which can make effective use of its capabilities. Information concerning Range use by organizations outside of DOE is presented. Range instrumentation and support facilities are described in detail. This equipment represents the current state-of-the-art and reflects a continuing commitment by TTR management to field the most effective tracking and data acquisition system available.
Unal, C.; Nelson, R.
1991-01-01T23:59:59.000Z
After completion of the thermal-hydraulic model developed in a companion paper, the authors performed developmental assessment calculation of the model using steady-state and transient post-critical heat flux (CHF) data. This paper discusses the results of those calculations. The overall interfacial drag model predicted reasonable drag coefficients for both the nucleate boiling and the inverted annular flow (IAF) regimes. The predicted pressure drops agreed reasonably well with the measured data of two transient experiments, CCTF Run 14 and a Lehigh reflood test. The thermal-hydraulic model for post-CHF convective heat transfer predicted the rewetting velocities reasonably well for both experiments. The predicted average slope of the wall temperature traces for these tests showed reasonable agreement with the measured data, indicating that the transient-calculated precursory cooling rates agreed with measured data. The hot-patch model, in conjunction with the other thermal-hydraulic models, was capable of modeling the Winfrith post-CHF hot-patch experiments. The hot-patch model kept the wall temperatures at the specified levels in the hot-patch regions and did not allow any quench-front propagation from either the bottom or the top of the test section. The interfacial heat-transfer model tended to slightly underpredict the vapor temperatures. The maximum difference between calculated and measured vapor temperatures was 20%, with a 10% difference for the remainder of the runs considered. The wall-to-fluid heat transfer was predicted reasonably well, and the predicted wall temperatures were in reasonable agreement with measured data with a maximum relative error of less than 13%.
Battery Electric Vehicles: Range Optimization and Diversification for the U.S. Drivers
Lin, Zhenhong [ORNL] [ORNL
2012-01-01T23:59:59.000Z
Properly selecting the driving range is critical for accurately predicting the market acceptance and the resulting social benefits of BEVs. Analysis of transportation technology transition could be biased against battery electric vehicles (BEV) and mislead policy making, if BEVs are not represented with optimal ranges. This study proposes a coherent method to optimize the BEV driving range by minimizing the range-related cost, which is formulated as a function of range, battery cost, energy prices, charging frequency, access to backup vehicles, and the cost and refueling hassle of operating the backup vehicle. This method is implemented with a sample of 36,664 drivers, representing U.S. new car drivers, based on the 2009 National Household Travel Survey data. Key findings are: 1) Assuming the near term (2015) battery cost at $405/kWh, about 98% of the sampled drivers are predicted to prefer a range below 200 miles, and about 70% below 100 miles. The most popular 20-mile band of range is 57 to77 miles, unsurprisingly encompassing the Leaf s EPA-certified 73-mile range. With range limited to 4 or 7 discrete options, the majority are predicted to choose a range below 100 miles. 2) Found as a statistically robust rule of thumb, the BEV optimal range is approximately 0.6% of one s annual driving distance. 3) Reducing battery costs could motivate demand for larger range, but improving public charging may cause the opposite. 4) Using a single range to represent BEVs in analysis could significantly underestimate their competitiveness e.g. by $3226/vehicle if BEVs are represented with 73-mile range only or by $7404/BEV if with 150-mile range only. Range optimization and diversification into 4 or 7 range options reduce such analytical bias by 78% or 90%, respectively.
Viking Range: Proposed Penalty (2014-CE-23014)
Broader source: Energy.gov [DOE]
DOE alleged in a Notice of Proposed Civil Penalty that Viking Range, LLC failed to certify cooking products as compliant with the applicable energy conservation standards.
T. W. Murphy, Jr.; E. G. Adelberger; J. B. R. Battat; L. N. Carey; C. D. Hoyle; P. LeBlanc; E. L. Michelsen; K. Nordtvedt; A. E. Orin; J. D. Strasburg; C. W. Stubbs; H. E. Swanson; E. Williams
2007-11-08T23:59:59.000Z
A next-generation lunar laser ranging apparatus using the 3.5 m telescope at the Apache Point Observatory in southern New Mexico has begun science operation. APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) has achieved one-millimeter range precision to the moon which should lead to approximately one-order-of-magnitude improvements in the precision of several tests of fundamental properties of gravity. We briefly motivate the scientific goals, and then give a detailed discussion of the APOLLO instrumentation.
The Joint Essential Numerical Range of operators
Li, Chi-Kwong
The Joint Essential Numerical Range of operators: Convexity and Related Results Chi-Kwong Li Classification 47A12, 47A13, 47A55. Keywords Joint essential numerical range, self-adjoint operator, Hilbert the joint behavior of several operators A1, . . . , Am. One may see [1, 5, 12, 14, 15, 16, 19, 23, 28, 31
Range gated imaging experiments using gated intensifiers
McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M.; Payton, J.; Pena-Abeyta, C.R.
1999-03-01T23:59:59.000Z
A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.
Effective range from tetramer dissociation data
Hadizadeh, M R; Tomio, Lauro; Delfino, A; Frederico, T
2012-01-01T23:59:59.000Z
The shifts in the four-body recombination peaks, due to lowest order range corrections in the zero range results close to the unitary limit, are obtained and used to extract the corresponding effective range of a given atomic system. From the experimental values of the tetramer dissociation positions of an ultracold gas of cesium atoms close to broad Feshbach resonances, the effective ranges are extracted, with a weighted average given by 3.9$\\pm 0.8 R_{{vdW}}$, where $R_{{vdW}}$ is the van der Waals length scale. This result is consistent with the van der Waals potential tail for the $Cs_2$ system. The method can be generally applied to other cold atom experimental setups to determine the corresponding effective range.
approximately constrained elastic: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
systems. The method approximates the distribution of the system state using a finite number of particles. By expressing these particles in terms of the control variables, we are...
approximate distributed dynamic: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
2 The Relation between Approximation in Distribution and Shadowing in Molecular Dynamics Mathematics Websites Summary: analysis is to explain the apparent reliabil- ity of...
approximate dynamic programming: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
STOCK Paris-Sud XI, Universit de 10 Approximate dynamic programming using model-free Bellman Residual Elimination MIT - DSpace Summary: This paper presents an...
Approximating K-means-type clustering via semidefinite programming
Jiming Peng
2005-04-22T23:59:59.000Z
Apr 22, 2005 ... Approximating K-means-type clustering via semidefinite ... Abstract: One of the fundamental clustering problems is to assign $n$ points into $k$ ...
Outcome-Space Outer Approximation Algorithm for Linear ...
2007-07-20T23:59:59.000Z
Jul 20, 2007 ... This paper presents an outcome-space outer approximation algo- rithm for globally solving the linear multiplicative programming prob- lem.
approximate analytical structural: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
developed method has been extended to a nonlocal equation arising in steady water wave propagation in two dimensions. We obtain analyic approximation of steady water wave...
Finding approximately rank-one submatrices with the nuclear norm ...
2010-11-08T23:59:59.000Z
We propose a convex optimization formulation with the nuclear norm and l1-norm to find a large approximately rank-one submatrix of a given nonnegative matrix ...
Finding approximately rank-one submatrices with the nuclear norm ...
Xuan Vinh Doan
2010-11-08T23:59:59.000Z
Nov 8, 2010 ... Abstract: We propose a convex optimization formulation with the nuclear norm and $\\ell_1$-norm to find a large approximately rank-one ...
aerodynamic response approximation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Page Topic Index 1 Managing Approximate Models in Evolutionary Aerodynamic Design Optimization Computer Technologies and Information Sciences Websites Summary: algorithm to a...
approximate entropy based: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
equation (1) nt + div n n Jngel, Ansgar 7 Regularization with Approximated L2 Maximum Entropy Method Physics Websites Summary: of a generalized moment of defined...
approximate block newton: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Abstract An extended product-form approximation, based on the principle of maximum entropy (ME), is characterised Ould-Khaoua, Mohamed 28 Low-lying dipole response...
ON LEAST SQUARES EUCLIDEAN DISTANCE MATRIX APPROXIMATION AND COMPLETION
in biological or engineering applications, including molecular structure analysis, protein folding problem. distance geometry, least squares approximation, matrix completion, molecular structure, protein folding
ON LEAST SQUARES EUCLIDEAN DISTANCE MATRIX APPROXIMATION AND COMPLETION
in biological or engineering applications, including molecular structure analysis, protein folding problem approximation, matrix completion, molecular structure, protein folding, conformational analysis. 1. Introduction
N /A
2003-02-24T23:59:59.000Z
The U.S. Department of Energy (DOE) proposes to consent to a proposal by the Puerto Rico Electric Power Authority (PREPA) to allow public access to the Boiling Nuclear Superheat (BONUS) reactor building located near Rincon, Puerto Rico for use as a museum. PREPA, the owner of the BONUS facility, has determined that the historical significance of this facility, as one of only two reactors of this design ever constructed in the world, warrants preservation in a museum, and that this museum would provide economic benefits to the local community through increased tourism. Therefore, PREPA is proposing development of the BONUS facility as a museum.
Neutron scattering and extra short range interactions
V. V. Nesvizhevsky; G. Pignol; K. V. Protasov
2007-11-14T23:59:59.000Z
The available data on neutron scattering were analyzed to constrain a hypothetical new short-range interaction. We show that these constraints are several orders of magnitude better than those usually cited in the range between 1 pm and 5 nm. This distance range occupies an intermediate space between collider searches for strongly coupled heavy bosons and searches for new weak macroscopic forces. We emphasise the reliability of the neutron constraints in so far as they provide several independent strategies. We have identified the most promising way to improve them.
Weber, J. W.; Bol, A. A. [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Sanden, M. C. M. van de [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Dutch Institute for Fundamental Energy Research (DIFFER), Nieuwegein (Netherlands)
2014-07-07T23:59:59.000Z
This work presents an improved thin film approximation to extract the optical conductivity from infrared transmittance in a simple yet accurate way. This approximation takes into account the incoherent reflections from the backside of the substrate. These reflections are shown to have a significant effect on the extracted optical conductivity and hence on derived parameters as carrier mobility and density. By excluding the backside reflections, the error for these parameters for typical chemical vapor deposited (CVD) graphene on a silicon substrate can be as high as 17% and 45% for the carrier mobility and density, respectively. For the mid- and near-infrared, the approximation can be simplified such that the real part of the optical conductivity is extracted without the need for a parameterization of the optical conductivity. This direct extraction is shown for Fourier transform infrared (FTIR) transmittance measurements of CVD graphene on silicon in the photon energy range of 370–7000?cm{sup ?1}. From the real part of the optical conductivity, the carrier density, mobility, and number of graphene layers are determined but also residue, originating from the graphene transfer, is detected. FTIR transmittance analyzed with the improved thin film approximation is shown to be a non-invasive, easy, and accurate measurement and analysis method for assessing the quality of graphene and can be used for other 2-D materials.
An Approximate Inference Approach to Temporal Optimization in Optimal Control
Vijayakumar, Sethu
on iterative local approximations present a practical approach to optimal control in robotic systems. However the optimal control framework. The proposed approach, which is applicable to plants with non-linear dynamicsAn Approximate Inference Approach to Temporal Optimization in Optimal Control Konrad C. Rawlik
THE DIFFUSION APPROXIMATION FOR THE LINEAR BOLTZMANN EQUATION
THE DIFFUSION APPROXIMATION FOR THE LINEAR BOLTZMANN EQUATION WITH VANISHING SCATTERING COEFFICIENT equation, Diffusion approximation, Neutron transport equation, Radiative transfer equation subject, 23], neutron transport theory [27]. A typical model linear Boltzmann equation is (t +· x)f(t,x,)= 1
Uncertainty, Performance, and Model Dependency in Approximate Adaptive Nonlinear Control
Szepesvari, Csaba
Uncertainty, Performance, and Model Dependency in Approximate Adaptive Nonlinear Control M. French, and the performance of a class of approximate model based adaptive controllers is studied. An upper performance bound uncertainty model; control effort bounds require both L 2 and L 1 uncertainty models), and various structural
Technical Note Variational free energy and the Laplace approximation
Penny, Will
Technical Note Variational free energy and the Laplace approximation Karl Friston,a, Jérémie the variational free energy under the Laplace approximation, with a focus on accounting for additional model complexity induced by increasing the number of model parameters. This is relevant when using the free energy
Energy Content of Colliding Plane Waves using Approximate Noether Symmetries
M. Sharif; Saira Waheed
2011-09-19T23:59:59.000Z
This paper is devoted to study the energy content of colliding plane waves using approximate Noether symmetries. For this purpose, we use approximate Lie symmetry method of Lagrangian for differential equations. We formulate the first-order perturbed Lagrangian for colliding plane electromagnetic and gravitational waves. It is shown that in both cases, there does not exist
Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction
Veatch, Michael H.
of approximating functions for the differential cost. The first contribution of this paper is identifying new or piece-wise quadratic. Fluid cost has been used to initialize the value iteration algorithm [5Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction Michael H
Approximation of Axisymmetric Darcy Flow V.J. Ervin
Ervin, Vincent J.
approximation of the Darcy equations in an ax- isymmetric domain, subject to axisymmetric data. Rewriting of convergence for the RT and BDM approximations. Key words. axisymmetric flow; Darcy equation, LBB condition AMSApproximation of Axisymmetric Darcy Flow V.J. Ervin Department of Mathematical Sciences Clemson
Parametric Optimization of Artificial Neural Networks for Signal Approximation Applications
Parametric Optimization of Artificial Neural Networks for Signal Approximation Applications J. Lane.thames@gatech.edu randal.abler@gatech.edu dirk.schaefer@me.gatech.edu ABSTRACT Artificial neural networks are used to solve set of configuration parameters for artificial neural networks such that the network's approximation
Pixelcuts: Scalable Approximate Illumination from Many Point Lights
Keinan, Alon
Pixelcuts: Scalable Approximate Illumination from Many Point Lights Pramook Khungurn, Thatchaphol approximate low-frequency illumination from many point lights. Its running time is O(n+mk) where n is the number of pixels, m is the number of point lights, and k is a constant the user specifies. Our algorithm
L^p Bernstein Inequalities and Radial Basis Function Approximation
Ward, John P.
2012-10-19T23:59:59.000Z
proving Bernstein inequalites for the RBF approximants, we will be able to use them to derive corresponding inverse theorems. Direct theorems concerning approximation by RBFs will be the focus of Section 4 3. The abilty of Green’s functions to invert di...
Fresnel approximations for acoustic fields of rectangularly symmetric sources
Mast, T. Douglas
Fresnel approximations for acoustic fields of rectangularly symmetric sources T. Douglas Masta for determining the acoustic fields of rectangularly symmetric, baffled, time-harmonic sources under the Fresnel. The expressions presented are generalized to three different Fresnel approximations that correspond, respectively
Approximation of Harmonic Maps and Wave Maps Soren Bartels
Bartels, Soeren
Approximation of Harmonic Maps and Wave Maps SÂ¨oren Bartels Partial differential equations to certain boundary condtions. If X = then critical points u : N are called harmonic maps into N, Â·) = u0, tu(0, Â·) = v0. To approximate harmonic maps or wave maps we consider a regular triangula- tion
New approximation for free surface flow of groundwater: capillarity correction
Walter, M.Todd
capillarity correction for free surface groundwater flow as modelled by the Boussinesq equation is re; Shallow flow expansion; Simplified approximation 1. Introduction Groundwater heads in coastal aquifersNew approximation for free surface flow of groundwater: capillarity correction D.-S. Jeng a,*, B
Long range transport of acid rain precursors
Fay, James A.
1983-01-01T23:59:59.000Z
A model of the long range transport of primary and secondary pollutants derived by Fay and Rosenzweig (1) is applied to the problem of the transport of acid rain precursors. The model describes the long term average (annual ...
APS Long Range Schedule FY1996
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Long Range Commissioning Schedule for FY1996 Date First Shift 0:00-8:00 Second Shift 8:00-16:00 Third Shift 16:00-24:00 31596 SR Studies 1-ID-A Shielding Verification SR Studies...
Descriptions of Range and Pasture Plants
Ragsdale, Bobby; Welch, Tommy G.
2000-05-03T23:59:59.000Z
Characteristics of common range and pasture plants are listed in this publication. The common and scientific name of each species are given, along with the species' value as a grazing plant for wildlife and livestock....
Active dendrites enhance neuronal dynamic range
Leonardo L. Gollo; Osame Kinouchi; Mauro Copelli
2009-08-08T23:59:59.000Z
Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the last decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of active dendritic trees is a highly non-linear function of their afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease of dynamic range.
Systematic ranging and late warning asteroid impacts
Farnocchia, D; Micheli, M
2015-01-01T23:59:59.000Z
We describe systematic ranging, an orbit determination technique especially suitable to assess the near-term Earth impact hazard posed by newly discovered asteroids. For these late warning cases, the time interval covered by the observations is generally short, perhaps a few hours or even less, which leads to severe degeneracies in the orbit estimation process. The systematic ranging approach gets around these degeneracies by performing a raster scan in the poorly-constrained space of topocentric range and range rate, while the plane of sky position and motion are directly tied to the recorded observations. This scan allows us to identify regions corresponding to collision solutions, as well as potential impact times and locations. From the probability distribution of the observation errors, we obtain a probability distribution in the orbital space and then estimate the probability of an Earth impact. We show how this technique is effective for a number of examples, including 2008 TC3 and 2014 AA, the only tw...
COLORADO FRONT RANGE SEISMICITY AND SEISMIC HAZARD
Sheehan, Anne F.
COLORADO FRONT RANGE SEISMICITY AND SEISMIC HAZARD Anne F. Sheehan University of Colorado, seismic, seismicity, crust, fault, hazard ABSTRACT Construction of seismic hazard and risk maps depends upon carefully constrained input parameters including background seismicity, seismic attenuation
Long range interactions in nanoscale science
Rajter, Richard F.
Our understanding of the “long range” electrodynamic, electrostatic, and polar interactions that dominate the organization of small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces ...
Properties of the Boltzmann equation in the classical approximation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Tanji, Naoto; Epelbaum, Thomas; Gelis, Francois; Wu, Bin
2014-12-01T23:59:59.000Z
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since onemore »has also access to the non-approximated result for comparison.« less
Properties of the Boltzmann equation in the classical approximation
Tanji, Naoto [Nishina Center, RIKEN, Wako (Japan). Theoretical Research Division; Brookhaven National Lab. (BNL), Upton, NY (United States); Epelbaum, Thomas [Institut de Physique Theorique (France); Gelis, Francois [Institut de Physique Theorique (France); Wu, Bin [Institut de Physique Theorique (France)
2014-12-01T23:59:59.000Z
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
Programmable near-infrared ranging system
Everett, Jr., Hobart R. (San Diego, CA)
1989-01-01T23:59:59.000Z
A high angular resolution ranging system particularly suitable for indoor plications involving mobile robot navigation and collision avoidance uses a programmable array of light emitters that can be sequentially incremented by a microprocessor. A plurality of adjustable level threshold detectors are used in an optical receiver for detecting the threshold level of the light echoes produced when light emitted from one or more of the emitters is reflected by a target or object in the scan path of the ranging system.
Yoder, Graydon L.
1980-01-01T23:59:59.000Z
Dispersed flow consists of small liquid droplets entrained in a flowing vapor. This flow regime can occur in cryogenic equipment, in steam generators, and during nuclear reactor loss of coolant accidents. A theoretical ...
Efficient Approximation of Diagonal Unitaries over the Clifford+T Basis
Jonathan Welch; Alex Bocharov; Krysta M. Svore
2014-12-22T23:59:59.000Z
We present an algorithm for the approximate decomposition of diagonal operators, focusing specifically on decompositions over the Clifford+$T$ basis, that minimize the number of phase-rotation gates in the synthesized approximation circuit. The equivalent $T$-count of the synthesized circuit is bounded by $k \\, C_0 \\log_2(1/\\varepsilon) + E(n,k)$, where $k$ is the number of distinct phases in the diagonal $n$-qubit unitary, $\\varepsilon$ is the desired precision, $C_0$ is a quality factor of the implementation method ($1total entanglement cost (in $T$ gates). We determine an optimal decision boundary in $(k,n,\\varepsilon)$-space where our decomposition algorithm achieves lower entanglement cost than previous state-of-the-art techniques. Our method outperforms state-of-the-art techniques for a practical range of $\\varepsilon$ values and diagonal operators and can reduce the number of $T$ gates exponentially in $n$ when $k << 2^n$.
Flux-Limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability
Boss, Alan P
2008-01-01T23:59:59.000Z
Both core accretion and disk instability appear to be required as formation mechanisms in order to explain the entire range of giant planets found in extrasolar planetary systems. Disk instability is based on the formation of clumps in a marginally-gravitationally unstable protoplanetary disk. These clumps can only be expected to contract and survive to become protoplanets if they are able to lose thermal energy through a combination of convection and radiative cooling. Here we present several new three dimensional, radiative hydrodynamics models of self-gravitating protoplanetary disks, where radiative transfer is handled in the flux-limited diffusion approximation. We show that while the flux-limited models lead to higher midplane temperatures than in a diffusion approximation model without the flux-limiter, the difference in temperatures does not appear to be sufficiently high to have any significant effect on the formation of self-gravitating clumps. Self-gravitating clumps form rapidly in the models both...
Ekblad, Steven Linn
1989-01-01T23:59:59.000Z
strategic resource management plans. Individual management skills and managerial environment have not been considered when predicting biological and economic response of range management practices. Risk for individual managers adopting unsuited... APPENDIX Prototype Range Management Skills Survey. Range Management Skills Survey Survey Data Tables. Validation Figures. VITA 64 65 74 92 104 106 1X LIST OP FIGURES FIGURE Page 1. The Range Con expert system in relation to the Resource...
Laser Range Finder Objective: Use a forward pointing laser range finder to
Wirthlin, Michael J.
Laser Range Finder Objective: Use a forward pointing laser range finder to detect and avoid obstacles. Principle Investigators: Randy Beard, Tim McLain Laser Range Finder Opti-Logic RS400 Laser path, laser detects object. 2. Upon detection, insert cylindrical object into world map and plan path
Usefulness of bound-state approximations in reaction theory
Adhikari, S.K.
1981-08-01T23:59:59.000Z
A bound-state approximation when applied to certain operators, such as the many-body resolvent operator for a two-body fragmentation channel, in many-body scattering equations, reduces such equations to equivalent two-body scattering equations which are supposed to provide a good description of the underlying physical process. In this paper we test several variants of bound-state approximations in the soluble three-boson Amado model and find that such approximations lead to weak and unacceptable kernels for the equivalent two-body scattering equations and hence to a poor description of the underlying many-body process.
Topological phases with long-range interactions
Gong, Zhe-Xuan; Hu, Anzi; Wall, Michael L; Foss-Feig, Michael; Gorshkov, Alexey V
2015-01-01T23:59:59.000Z
Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.
Supersymmetric inversion of effective-range expansions
Bikashkali Midya; Jérémie Evrard; Sylvain Abramowicz; O. L. Ramírez Suárez; Jean-Marc Sparenberg
2015-05-26T23:59:59.000Z
A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.
Supersymmetric inversion of effective-range expansions
Midya, Bikashkali; Abramowicz, Sylvain; Suárez, O L Ramírez; Sparenberg, Jean-Marc
2015-01-01T23:59:59.000Z
A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.
Supersymmetric inversion of effective-range expansions
Bikashkali Midya; Jérémie Evrard; Sylvain Abramowicz; O. L. Ramírez Suárez; Jean-Marc Sparenberg
2015-01-16T23:59:59.000Z
A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.
Topological phases with long-range interactions
Zhe-Xuan Gong; Mohammad F. Maghrebi; Anzi Hu; Michael L. Wall; Michael Foss-Feig; Alexey V. Gorshkov
2015-05-12T23:59:59.000Z
Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.
Inverse bremsstrahlung heating rate in xenon clusters in the eikonal approximation
Dey, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Roy, A. C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math, 711202 West Bengal (India)
2013-03-15T23:59:59.000Z
We report inverse bremsstrahlung (IB) heating rates in the eikonal approximation (EA). The present analysis is performed using the plasma-screened Rogers and Debye potentials for Xe clusters with two different charge states (6 and 10). We compare the eikonal results with the first Born approximation (FBA) and classical-simulation (CL-sim) (Moll et al., Phys. Plasmas 19, 033303 (2012)) calculations for clusters in infrared light. Calculations have been performed for the field strength of 2.6 Multiplication-Sign 10{sup 8} V/cm. We find that compared to the FBA and CL-sim methods, the IB heating rate in the EA is less sensitive to the choice of the two potentials considered here. The present EA calculation shows that the influence of the inner structure of atomic ion on the heating rate is more prominent for the smaller ion charge (Xe{sup 6+}). In the case of low laser field approximation based on the elastic transport cross sections, it is seen that in contrast to the FBA and classical methods, the heating rate predicted by the EA does not deviate much all over the range of mean kinetic energy of electrons (20-500 eV) considered here for both the charge states of xenon (Xe{sup 6+} and Xe{sup 10+}). Furthermore, for the Rogers potential, EA is found to be in closer agreement with the classical method than the FBA. We also compare the results of the IB heating rate using the present and low-field approximation approaches to the above three methods and observe that the magnitudes of the IB heating rate calculated in the low field approximation are, in general, higher than the corresponding values predicted by the present approach for both the electron-ion potentials.
A viscous-convective instability in laminar Keplerian thin discs. II. Anelastic approximation
Shakura, N
2015-01-01T23:59:59.000Z
Using the anelastic approximation of linearised hydrodynamic equations, we investigate the development of axially symmetric small perturbations in thin Keplerian discs. The sixth-order dispersion equation is derived and numerically solved for different values of relevant physical parameters (viscosity, heat conductivity, disc semi-thickness and vertical structure). The analysis reveals the appearance of two overstable modes which split out from the classical Rayleigh inertial modes in a wide range of the parameters in both ionized and neutral gases. These modes have a viscous-convective nature and can serve as a seed for turbulence in astrophysical discs even in the absence of magnetic fields.
Approximating the Minimum Spanning Tree Weight in Sublinear Time
Trevisan, Luca
Approximating the Minimum Spanning Tree Weight in Sublinear Time Bernard Chazelle #3; Ronitt a parameter 0 minimum spanning tree- components algorithm picks O(1=#15; 2 ) vertices in the graph and then grows \\local spanning trees" whose
Approximate dynamic programming with applications in multi-agent systems
Valenti, Mario J. (Mario James), 1976-
2007-01-01T23:59:59.000Z
This thesis presents the development and implementation of approximate dynamic programming methods used to manage multi-agent systems. The purpose of this thesis is to develop an architectural framework and theoretical ...
PLASMA Approximate Dynamic Programming finally cracks the locomotive optimization problem
Powell, Warren B.
PLASMA Â Approximate Dynamic Programming finally cracks the locomotive optimization problem schedules and new operating policies. PLASMA is currently running at Norfolk Southern for strategic of PLASMA: Each locomotive is modeled individually, making it possible to capture both horsepower
Fast Approximations for Online Scheduling of Outpatient Procedure ...
2014-06-18T23:59:59.000Z
Jun 18, 2014 ... ? > SmU , any permutation of items to bins that uses the full amount of ... approximation solution value will both tend to cf mU + cv(? ? SmU ).
SPLITTING MANIFOLD APPROXIMATE FIBRATIONS J. L. BRYANT AND P. KIRBY
Aluffi, Paolo
SPLITTING MANIFOLD APPROXIMATE FIBRATIONS J. L. BRYANT AND P. KIRBY Abstract. Suppose M, embeddings. Partially supported by NSF grant DMS-9626624. 1 #12; 2 J. L. BRYANT AND P. KIRBY 2. Definitions
Numerical Approximations of Stochastic Optimal Stopping and Control Problems
Siska, David
2007-01-01T23:59:59.000Z
We study numerical approximations for the payoff function of the stochastic optimal stopping and control problem. It is known that the payoff function of the optimal stopping and control problem corresponds to the solution ...
Approximate inference : decomposition methods with applications to networks
Jung, Kyomin
2009-01-01T23:59:59.000Z
Markov random field (MRF) model provides an elegant probabilistic framework to formulate inter-dependency between a large number of random variables. In this thesis, we present a new approximation algorithm for computing ...
Approximate translation : media, narrative, and experience in urban design
Crisman, Jonathan
2013-01-01T23:59:59.000Z
Approximate translation is developed as a design process through which the place-embedded history of an urban environment can be understood, allowing for better design and intervention in that urban environment. Generally, ...
A multiscale approximation algorithm for the cardinality constrained knapsack problem
Krishnan, Bharath Kumar
2006-01-01T23:59:59.000Z
I develop a multiscale approximation algorithm for the cardinality constrained knapsack problem. The algorithm consists of three steps: a rounding and reduction step where a hierarchical representation of the problem data ...
Generalized eikonal approximation for strong-field ionization
Vélez, F Cajiao; Kami?ski, J Z
2015-01-01T23:59:59.000Z
We develop the eikonal perturbation theory to describe the strong-field ionization by finite laser pulses. This approach in the first order with respect to the binding potential (the so-called generalized eikonal approximation) avoids a singularity at the potential center. Thus, in contrast to the ordinary eikonal approximation, it allows to treat rescattering phenomena in terms of quantum trajectories. We demonstrate how the first Born approximation and its domain of validity follow from eikonal perturbation theory. Using this approach, we study the coherent diffraction patterns in photoelectron energy spectra and their modifications induced by the interaction of photoelectrons with the atomic potential. Along with these first results, we discuss the prospects of using the generalized eikonal approximation to study strong-field ionization from multi-centered atomic systems and to study other strong-field phenomena.
Approximate Associative Memristive Memory for Energy-Efficient GPUs
Liebling, Michael
Approximate Associative Memristive Memory for Energy-Efficient GPUs Abbas Rahimi, Amirali Ghofrani at the architectural and algorithmic levels. At the hardware level, energy-efficiency techniques that employ voltage
Penumbra Maps: Approximate Soft Shadows in Real-Time
Wyman, Chris
;Penumbra Map Assumptions Â· A hard shadow is a reasonable approximation for a shadow's umbra Â· Object silhouettes remain constant over light's surface #12;Key Insight Â· When using a hard shadow as the umbra, all
Shorter Tours by Nicer Ears 7/5-approximation for graphic TSP,
Vygen, Jens
case called Graphic TSP: approximation ratio 1.5 - (Gharan, Saberi, Singh [2011]) approximation ratio 1, Saberi, Singh [2011]) approximation ratio 1.461 (M¨omke, Svensson [2011]) approximation ratio 1
Approximation of linear partial differential equations on spheres
Le Gia, Quoc Thong
2004-09-30T23:59:59.000Z
Subject: Mathematics iii ABSTRACT Approximation of Linear Partial Di®erential Equations on Spheres. (August 2003) Quoc Thong Le Gia, B.S., University of New South Wales; M.S., Texas A&M University Co{Chairs of Advisory Committee: Dr. Joseph D. Ward Dr... . . . . . . . . . . . . . . . . . 15 II INTERPOLATION ON SPHERES BY DILATED SBFs : : : : 16 A. Approximation theorems . . . . . . . . . . . . . . . . . . . 16 B. Locally supported basis functions on Rn+1 and Sn . . . . . 18 1. Compactly supported strictly positive deŻnite func- tions...
Mean field approximation for noisy delay coupled excitable neurons
Nikola Buric; Dragana Rankovic; Kristina Todorovic; Nebojsa Vasovic
2010-03-26T23:59:59.000Z
Mean field approximation of a large collection of FitzHugh-Nagumo excitable neurons with noise and all-to-all coupling with explicit time-delays, modelled by $N\\gg 1$ stochastic delay-differential equations is derived. The resulting approximation contains only two deterministic delay-differential equations but provides excellent predictions concerning the stability and bifurcations of the averaged global variables of the exact large system.
Range Creek Calibrated Dates Beta-202190
Provancher, William
Range Creek Calibrated Dates 0 200 400 600 800 1000 1200 1400 Beta-202190 Beta-175753 Beta-175755 Beta-235067 Beta-202189 Beta-214831 Beta-202188 Beta-202191 Beta-203630 Beta-214832 Beta-175754 Beta a Carbon-14 calibrated date (95% CI) between 1000 and 1200 C.E. (Figure 5: Beta-235067). The calibrated
Compact range for variable-zone measurements
Burnside, Walter D. (Columbus, OH); Rudduck, Roger C. (Columbus, OH); Yu, Jiunn S. (Albuquerque, NM)
1988-01-01T23:59:59.000Z
A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.
6, 1018310216, 2006 Long-range transport
Boyer, Edmond
ACPD 6, 1018310216, 2006 Long-range transport of Asian dust and air pollutants to Taiwan C.-Y. Lin and air pollutants to Taiwan: observed evidence and model simulation C.-Y. Lin 1 , Z. Wang 2 , W.-N. Chen and air pollutants to Taiwan C.-Y. Lin et al. Title Page Abstract Introduction Conclusions References
Wide temperature range seal for demountable joints
Sixsmith, H.; Valenzuela, J.A.; Nutt, W.E.
1991-07-23T23:59:59.000Z
The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof. 6 figures.
Wide temperature range seal for demountable joints
Sixsmith, Herbert (Norwich, VT); Valenzuela, Javier A. (Grantham, NH); Nutt, William E. (Enfield, NH)
1991-07-23T23:59:59.000Z
The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof.
Impulse radar with swept range gate
McEwan, Thomas E. (Livermore, CA)
1998-09-08T23:59:59.000Z
A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna (10), so a background subtraction is not needed, simplifying the circuitry while improving performance. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive (24) and transmit cavities (22) by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. The antennas can be arranged in a side-by-side parallel spaced apart configuration or in a coplanar opposed configuration which significantly reduces main bang coupling.
Impulse radar with swept range gate
McEwan, T.E.
1998-09-08T23:59:59.000Z
A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. The antennas can be arranged in a side-by-side parallel spaced apart configuration or in a coplanar opposed configuration which significantly reduces main bang coupling. 25 figs.
Electrical Engineering Technology (EET) LONG RANGE SCHEDULE
and Machinery C T C T EET 365W Electrical Power & Machinery Laboratory C C, V V C C, V V EET 370T EnergyElectrical Engineering Technology (EET) LONG RANGE SCHEDULE Course Number and Name Fall 2010 Spr 2011 Sum 2011 Fall 2011 Spr 2012 Sum 2012 Fall 2012 Spr 2013 Sum 2013 Fall 2013 Spr 2014 Sum 2014 EET
Mailhes, Corinne
#12;#12;Abstract We study the continuous extractive distillation of minimum and maximum boiling on operating parameters: distillate product purity and recovery, reflux ratio R and entrainer feed flow rate. For the 1.0-2 class both A and B can be distillated. For one of them there exists a maximum entrainer - feed
Faust, Christophor Randall
1995-01-01T23:59:59.000Z
The thermal hydraulic simulation code RELAP5/MOD3.1.1 was utilized to model General Electric's Simplified Boiling Water Reactor plant. The model of the plant was subjected to a small break loss of coolant accident occurring from a guillotine shear...
Approximate semi-analytical solutions for the steady-state expansion of a contactor plasma
Camporeale, E; MacDonald, E A
2015-01-01T23:59:59.000Z
We study the steady-state expansion of a collisionless, electrostatic, quasi-neutral plasma plume into vacuum, with a fluid model. We analyze approximate semi-analytical solutions, that can be used in lieu of much more expensive numerical solutions. In particular, we focus on the earlier studies presented in Parks and Katz (1979), Korsun and Tverdokhlebova (1997), and Ashkenazy and Fruchtman (2001). By calculating the error with respect to the numerical solution, we can judge the range of validity for each solution. Moreover, we introduce a generalization of earlier models that has a wider range of applicability, in terms of plasma injection profiles. We conclude by showing a straightforward way to extend the discussed solutions to the case of a plasma plume injected with non-null azimuthal velocity.
Wide range radioactive gas concentration detector
Anderson, David F. (Los Alamos, NM)
1984-01-01T23:59:59.000Z
A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.
Short-Range Nucleon-Nucleon Correlations
Douglas Higinbotham
2011-10-01T23:59:59.000Z
Valence-shell nucleon knock-out experiments, such as 12C(e,e'p)11B, measure less strength then is predicted by independent particle shell model calculations. The theoretical solution to this problem is to include the correlations between the nucleons in the nucleus in the calculations. Motivated by these results, many electron scattering experiments have tried to directly observe these correlations in order to gain new insight into the short-range part of the nucleon-nucleon potential. Unfortunately, many competing mechanisms can cause the same observable final-state as an initial-state correlation, making truly isolating the signal extremely challenging. This paper reviews the recent experimental evidence for short-range correlations, as well as explores the possibility that such correlations are responsible for the EMC effect in the 0.3 < xB < 0.7 deep inelastic scattering ratios.
Short-Range Nucleon-Nucleon Correlations
Higinbotham, Douglas W. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23601 (United States)
2011-10-24T23:59:59.000Z
Valence-shell nucleon knock-out experiments, such as {sup 12}C(e,e'p){sup 11}B, measure less strength then is predicted by independent particle shell model calculations. The theoretical solution to this problem is to include the correlations between the nucleons in the nucleus in the calculations. Motivated by these results, many electron scattering experiments have tried to isolate the signal from these correlations in order to gain new insight into the short-range part of the nucleon-nucleon potential. Unfortunately, many competing mechanisms can cause the same observable final-state as an initial-state correlation, making truly isolating the signal extremely challenging. This paper reviews the recent experimental evidence for short-range correlations, as well as explores the possibility that such correlations are responsible for the EMC effect in the 0.3
Intermediate Range Order and Transport Processes
Harting, Jens
Simulation Study February 7, 2005 Patrick Pfleiderer ICP, University of Stuttgart in Collaboration: 2 2 21 ),...,,( dt d mV i iNii r rrrF =-= t m ttt ttt t m t ttttt i ii ii i i iii 2 )()( )()( 2-range and responsible for covalent character · obtained from ab initio calculations · time step: 1.6fs 6 2 r C eA r eqq
What Range Herbivores Eat -- and Why
Lyons, Robert K.; Forbes, T. D. A.; Machen, Richard V.
1999-02-15T23:59:59.000Z
systems that have the chemicals need- ed to digest it. Cellulose is digested by fermenta- tion. Fermentation requires time and a con- ducive environment in the digestive system *Assistant Professor and Extension Range Specialist; Associate Professor... fermentation can take place. Some monogastrics (like horses, rabbits) have either an enlarged stomach or areas in the large intestine and/or cecum where fermentation can take place. Monogastrics with an enlarged stomach (like the hippopotamus) are called...
Causality and the effective range expansion
H. -W. Hammer; Dean Lee
2010-07-26T23:59:59.000Z
We derive the generalization of Wigner's causality bounds and Bethe's integral formula for the effective range parameter to arbitrary dimension and arbitrary angular momentum. We also discuss the impact of these constraints on the separation of low- and high-momentum scales and universality in low-energy scattering. Some of our results were summarized earlier in a letter publication. In this work, we present full derivations and several detailed examples.
Inertial range turbulence in kinetic plasmas
Howes, G G
2007-01-01T23:59:59.000Z
The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the ther...
Inertial range turbulence in kinetic plasmas
G. G. Howes
2007-11-27T23:59:59.000Z
The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the thermalization of fusion energy in burning plasmas.
Anisotropic Homogeneous Cosmologies in the Post-Newtonian Approximation
Tamath Rainsford
2000-07-23T23:59:59.000Z
In this paper we explore how far the post-Newtonian theory goes in overcoming the difficulties associated with anisotropic homogeneous cosmologies in the Newtonian approximation. It will be shown that, unlike in the Newtonian case, the cosmological equations of the post-Newtonian approximation are much more in the spirit of general relativity with regard to the nine Bianchi types and issues of singularities. The situations of vanishing rotation and vanishing shear are treated separately. The homogeneous Bianchi I model is considered as an example of a rotation-free cosmology with anisotropy. It is found in the Newtonian approximation that there are arbitrary functions that need to be given for all time if the initial value problem is to be well-posed, while in the post-Newtonian case there is no such need. For the general case of a perfect fluid only the post-Newtonian theory can satisfactorily describe the effects of pressure. This is in accordance with findings in an earlier paper where the post-Newtonian approximation was applied to homogeneous cosmologies. For a shear-free anisotropic homogeneous cosmology the Newtonian theory of Heckmann and Sch\\"ucking is explored. Comparisons with its relativistic and post-Newtonian counterparts are made. In the Newtonian theory solutions exist to which there are no analogues in general relativity. The post-Newtonian approximation may provide a way out.
Variational principles with Padé approximants for tearing mode analysis
Cole, Andrew J. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Finn, John M. [Applied Mathematics and Plasma Physics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)] [Applied Mathematics and Plasma Physics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)
2014-03-15T23:59:59.000Z
Tearing modes occur in several distinct physical regimes, and it is often important to compute the inner layer response for these modes with various effects. There is a need for an approximate and efficient method of solving the inner layer equations in all these regimes. In this paper, we introduce a method of solving the inner layer equations based on using a variational principle with Padé approximants. For all the regimes considered, the main layer equations to be solved are inhomogeneous, and Padé approximants give a convenient and efficient method of satisfying the correct asymptotic behavior at the edge of the layer. Results using this variational principle—Padé approximant method in three of these regimes is presented. These regimes are the constant-? resistive-inertial (RI) regime, the constant-? viscoresistive regime, and the non-constant-? inviscid tearing regime. The last regime includes the constant-? RI regime and the inertial regime. The results show that reasonable accuracy can be obtained very efficiently with Padé approximants having a small number of parameters.
Flux-Limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability
Alan P. Boss
2008-01-28T23:59:59.000Z
Both core accretion and disk instability appear to be required as formation mechanisms in order to explain the entire range of giant planets found in extrasolar planetary systems. Disk instability is based on the formation of clumps in a marginally-gravitationally unstable protoplanetary disk. These clumps can only be expected to contract and survive to become protoplanets if they are able to lose thermal energy through a combination of convection and radiative cooling. Here we present several new three dimensional, radiative hydrodynamics models of self-gravitating protoplanetary disks, where radiative transfer is handled in the flux-limited diffusion approximation. We show that while the flux-limited models lead to higher midplane temperatures than in a diffusion approximation model without the flux-limiter, the difference in temperatures does not appear to be sufficiently high to have any significant effect on the formation of self-gravitating clumps. Self-gravitating clumps form rapidly in the models both with and without the flux-limiter. These models suggest that the reason for the different outcomes of numerical models of disk instability by different groups cannot be attributed solely to the handling of radiative transfer, but rather appears to be caused by a range of numerical effects and assumptions. Given the observational imperative to have disk instability form at least some extrasolar planets, these models imply that disk instability remains as a viable giant planet formation mechanism.
Approximations by gravitational fields due to restricted unit point masses
Shull, Carolyn Sue Flowers
1973-01-01T23:59:59.000Z
approximations by Chui (1, 3, 4j and D. J. Newman $12$. Some open problems will be discussed including a conjecture by Chui f2]. I ht th ' th ~Pdl f~hA 1 Mth i I ~gociet is used as a pattern for format, CHAPTER I UNIFORM APPROXIMATION ON COMPACT SETS Let C... free analytic functions in D are not approximable. Also the following result was obtained in fgj . THEOREM 1. 4. A closed set R dis oint from a domain D which lies in som h lf- 1 ne H is ol omial a roximation set relative t b~fl fRt~tbf th I t f3d...
Non-perturbative QCD amplitudes in quenched and eikonal approximations
Fried, H.M. [Physics Department, Brown University, Providence, RI 02912 (United States); Grandou, T., E-mail: Thierry.Grandou@inln.cnrs.fr [Université de Nice-Sophia Antipolis, Institut Non Linéaire de Nice, UMR 6618 CNRS 7335, 1361 routes des Lucioles, 06560 Valbonne (France); Sheu, Y.-M., E-mail: ymsheu@alumni.brown.edu [Université de Nice-Sophia Antipolis, Institut Non Linéaire de Nice, UMR 6618 CNRS 7335, 1361 routes des Lucioles, 06560 Valbonne (France)
2014-05-15T23:59:59.000Z
Even though approximated, strong coupling non-perturbative QCD amplitudes remain very difficult to obtain. In this article, in eikonal and quenched approximations at least, physical insights are presented that rely on the newly-discovered property of effective locality. The present article also provides a more rigorous mathematical basis for the crude approximations used in the previous derivation of the binding potential of quarks and nucleons. Furthermore, the techniques of Random Matrix calculus along with Meijer G-functions are applied to analyze the generic structure of fermionic amplitudes in QCD. - Highlights: • We discuss the physical insight of effective locality to QCD fermionic amplitudes. • We show that an unavoidable delta function goes along with the effective locality property. • The generic structure of QCD fermion amplitudes is obtained through Random Matrix calculus.
Analytical approximations for x-ray cross sections III
Biggs, F; Lighthill, R
1988-08-01T23:59:59.000Z
This report updates our previous work that provided analytical approximations to cross sections for both photoelectric absorption of photons by atoms and incoherent scattering of photons by atoms. This representation is convenient for use in programmable calculators and in computer programs to evaluate these cross sections numerically. The results apply to atoms of atomic numbers between 1 and 100 and for photon energiesgreater than or equal to10 eV. The photoelectric cross sections are again approximated by four-term polynomials in reciprocal powers of the photon energy. There are now more fitting intervals, however, than were used previously. The incoherent-scattering cross sections are based on the Klein-Nishina relation, but use simpler approximate equations for efficient computer evaluation. We describe the averaging scheme for applying these atomic results to any composite material. The fitting coefficients are included in tables, and the cross sections are shown graphically. 100 graphs, 1 tab.
Aggelen, Helen van [Department of Inorganic and Physical Chemistry, Ghent University, Ghent (Belgium) [Department of Inorganic and Physical Chemistry, Ghent University, Ghent (Belgium); Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Yang [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States)] [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Weitao [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)] [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)
2014-05-14T23:59:59.000Z
Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H{sub 2}, and eliminates delocalization errors in H{sub 2}{sup +} and other single-bond systems. It gives surprisingly good non-bonded interaction energies – competitive with the ph-RPA – with the correct R{sup ?6} asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations.
Modern testing meets wide range of objectives
Ehlig-Economides, C.A.; Hegeman, P. (Schlumberger Oilfield Services, Houston, TX (United States)); Clark, G. (Schlumberger Oilfield Services, Aberdeen (United Kingdom))
1994-08-01T23:59:59.000Z
Testing sequences in two very different wells illustrate the wide range of objectives that are met with modern testing procedures. The first example is a drill stem test in an exploration well. The second test is in an established producing well. The exploration well test incorporated tubing-conveyed perforating, fluid sampling, production logging, and matrix stimulation to evaluate and properly treat near-well bore damage, as well as to investigate reservoir volume and characterize boundaries. The test on the established producer evaluated whether a workover could remedy lower than expected productivity. Production logging was combined with stationary transient measurements.
Tonopah Test Range 2030 Meeting Summary Report
NSTec Environmental Restoration
2009-04-01T23:59:59.000Z
Corrective Action Sites (CASs) and Corrective Action Units (CAUs) at the Tonopah Test Range (TTR) may be placed into three categories: Closed, Closed in Place, or Closure in Progress. CASs and CAUs where contaminants were either not detected or were cleaned up to within regulatory action levels are summarized. CASs and CAUs where contaminants and/or waste have been closed in place are summarized. There is also a table that summarizes the contaminant that has been closed at each site, if land-use restrictions are present, and if post-closure inspections are required.
Fan-less long range alpha detector
MacArthur, D.W.; Bounds, J.A.
1994-05-10T23:59:59.000Z
A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.
Short range correlations and the EMC effect
E. Piasetzky, L.B. Weinstein, D.W. Higinbotham, J. Gomez, O. Hen, R. Shneor
2011-04-01T23:59:59.000Z
The magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) is linearly related to the Short Range Correlation (SRC) scaling factor obtained from electron inclusive scattering. We speculate that the observed correlation is due to the fact that both the EMC effect and SRC are dominated by high momentum nucleons in the nucleus. The observed phenomenological relationship can be used to extract the ratio of the deuteron to the free pn-pair cross sections, the DIS cross section for a free neutron, View the MathML source, the ratio of the free neutron to free proton structure functions, and the u/d ratio in a free proton.
Range Fuels Biorefinery Groundbreaking | Department of Energy
Office of Environmental Management (EM)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011 Strategic2 OPAM615_CostNSAR - TProcuring SolarNo.Frequency |DepartmentEventRange Fuels
Rangely Oilfield Geothermal Area | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit with form History Facebook iconQuito,Jump to:Radiant ElectricRamkyRange
Rangely, Colorado: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro Industries Pvt Ltd Jump to: navigation, search Name:Rancia 2Rangely, Colorado: Energy
Range Fuels Biorefinery Groundbreaking | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOrigin of ContaminationHubs+18, 2012 Qualified11 Connecticut2 of 3)the Office98RainRaisingRange
On the approximation of crack shapes found during inservice inspection
Bhate, S.R.; Chawla, D.S.; Kushwaha, H.S. [Bhabha Atomic Research Centre, Bombay (India)] [and others
1997-04-01T23:59:59.000Z
This paper addresses the characterization of axial internal flaw found during inservice inspection of a pipe. J-integral distribution for various flaw shapes is obtained using line spring finite, element method. The peak J-value and its distribution across the crack is found to be characteristic feature of each shape. The triangular shape yields peak J-value away from the center, the point of depth. The elliptic approximation results in large overestimate of J-value for unsymmetric flaws. Triangular approximation is recommended for such flaws so that further service can be obtained from the component.
Perturbative stability of the approximate Killing field eigenvalue problem
Christopher Beetle; Shawn Wilder
2013-12-31T23:59:59.000Z
An approximate Killing field may be defined on a compact, Riemannian geometry by solving an eigenvalue problem for a certain elliptic operator. This paper studies the effect of small perturbations in the Riemannian metric on the resulting vector field. It shows that small metric perturbations, as measured using a Sobolev-type supremum norm on the space of Riemannian geometries on a fixed manifold, yield small perturbations in the approximate Killing field, as measured using a Hilbert-type square integral norm. It also discusses applications to the problem of computing the spin of a generic black hole in general relativity.
Dynamical entanglement versus symmetry and dynamics of classical approximations
Buric, Nikola [Department of Physics and Mathematics, Faculty of Pharmacy, University of Beograd, Vojvode Stepe 450, 11000 Belgrade (Serbia and Montenegro)
2006-05-15T23:59:59.000Z
It is shown that dynamical entanglement between two qubits depends on the symmetry of the quantum model. On the other hand, the latter is reflected in the qualitative properties of the dynamics of a classical approximation of the quantum system. For generic separable pure initial states, the dynamical entanglement is larger if the system is less symmetric and its classical approximation is chaotic. The influence of different types of Markov environments on the established relation between the dynamical entanglement, symmetry and the classical dynamics is also studied.
Chiaverini, John
We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K to room temperature (295 K) in a single ...
Short range, ultra-wideband radar with high resolution swept range gate
McEwan, Thomas E. (Livermore, CA)
1998-05-26T23:59:59.000Z
A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control.
Short range, ultra-wideband radar with high resolution swept range gate
McEwan, T.E.
1998-05-26T23:59:59.000Z
A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control. 14 figs.
August and September Approximately 29 percent from husks
minutes. Cool promptly in several changes of cold water and drain. Whole-kernel corn: Cut kernels from. Scrape the cobs with the back of the knife to remove the juice and the hearts of the kernels. Pack corn for approximately the same length of time the corn was blanched) and drain well. Tightly ',vrap ears individually
Fractal Inverse Problem: Approximation Formulation and Differential Methods
GuĂ©rin, Eric
Fractal Inverse Problem: Approximation Formulation and Differential Methods Â´Eric GuÂ´erin1 Introduction 1.1 Fractal Inverse Problem The fractal inverse problem is an important research area with a great number of potential application fields. It consists in finding a fractal model or code that generates
Approximating the Minimum Spanning Tree Weight in Sublinear Time
Goldwasser, Shafi
Approximating the Minimum Spanning Tree Weight in Sublinear Time #3; Bernard Chazelle y Ronitt a parameter 0 minimum span- ning tree in the graph and then grows \\local spanning trees" whose sizes are speci#12;ed by a stochastic process. From
Boundary approximate controllability of some linear parabolic April 5, 2013
Paris-Sud XI, Université de
Boundary approximate controllability of some linear parabolic systems April 5, 2013 Guillaume Olive controllability of two classes of linear parabolic systems, namely a system of n heat equations coupled through are the only ones concerning the boundary controllability of linear parabolic systems of heat-type. For more
Exact and Approximate Sampling by Systematic Stochastic Search
Tenenbaum, Josh
Exact and Approximate Sampling by Systematic Stochastic Search Vikash Mansinghka MIT BCS & CSAIL exact samples over high-dimensional spaces from exact sam- ples over lower-dimensional subspaces. Our do this by generalizing ideas from classic AI search to the stochastic setting. Just as systematic
An Equivalence Between Sparse Approximation and Support Vector Machines 1
Poggio, Tomaso
An Equivalence Between Sparse Approximation and Support Vector Machines 1 Federico Girosi Center is equivalent to SVM in the following sense: if applied to the same data set the two techniques give the same; Chen, Donoho and Saunders, 1995), are actually equivalent, in the case of noiseless data. By equivalent
Calculating reactor transfer functions by Pade approximation via Lanczos algorithm
PĂˇzsit, Imre
Calculating reactor transfer functions by PadeĂ? approximation via Lanczos algorithm Zhifeng Kuang a function of a reactor, i.e. the neutron noise induced by a localised perturbation is calculated in one, *,1 , Imre PaĂ? zsit a , Axel Ruhe b a Department of Reactor Physics, Chalmers University of Technology
Non-linear regression models for Approximate Bayesian Computation
Robert, Christian P.
Non-linear regression models for Approximate Bayesian Computation (ABC) Michael Blum Olivier ABC #12;Blum and OF (2009) suggest the use of non-linear conditional heteroscedastic regression models) Linear regression-based ABC can sometimes be improved #12;abc of ABC Using stochastic simulations
Sensitivity, Approximation and Uncertainty in Power System Dynamic Simulation
1 Sensitivity, Approximation and Uncertainty in Power System Dynamic Simulation Ian A. Hiskens, Fellow, IEEE Jassim Alseddiqui Student Member, IEEE Abstract-- Parameters of power system models the influence of uncertainty in simulations of power system dynamic behaviour. It is shown that trajectory
Geometric Wavelet Approximations and Abdourrahmane M. Atto1
Paris-Sud XI, Université de
1 Geometric Wavelet Approximations and Dierencing Abdourrahmane M. Atto1 , Emmanuel Trouve2 Jean-Marie Nicolas3 , Abstract--The paper introduces the concept of ge- ometric wavelets defined from multiplicative algebras. These wavelets perform generalized geometric approx- imations and differencing. The paper also
A Study of Approximate Data Management Techniques for Sensor Networks
Martin, Ralph R.
the monitoring operation of sensor nodes by efficiently using their limited energy, bandwidth and computation. The network can therefore be treated as a distributed sensor data management system. Sensor networks differA Study of Approximate Data Management Techniques for Sensor Networks Adonis Skordylis, Niki
Benchmarking a Scalable Approximate Dynamic Programming Algorithm for Stochastic Control
Powell, Warren B.
for the optimal control of such power systems are critical for the deployment of reliable and more economical and within 1.34% in stochastic ones, much lower than those obtained using model predictive control. We useBenchmarking a Scalable Approximate Dynamic Programming Algorithm for Stochastic Control
Introduction Approximately 40% of rural Ethiopia (WaterAid, 2010)
Walter, M.Todd
Introduction Approximately 40% of rural Ethiopia (WaterAid, 2010) lacks access to clean water for water pumping is one alternative in the rural areas of Ethiopia since most of the population has technologies for water pumping in Ethiopia and especially in Amhara Region is limited. The promotion
Combining Conjugate Direction Methods with Stochastic Approximation of Gradients
Schraudolph, Nicol N.
Combining Conjugate Direction Methods with Stochastic Approximation of Gradients #3; Nicol N-8092 Zurich, Switzerland http://www.icos.ethz.ch/ Abstract The method of conjugate directions provides from conjugate gra- dient in the stochastic (online) setting, us- ing fast Hessian-gradient products
Combining Conjugate Direction Methods with Stochastic Approximation of Gradients
Schraudolph, Nicol N.
Combining Conjugate Direction Methods with Stochastic Approximation of Gradients Nicol N-8092 Z¨urich, Switzerland http://www.icos.ethz.ch/ Abstract The method of conjugate directions provides conjugate gra- dient in the stochastic (online) setting, us- ing fast Hessian-gradient products to set up
APPROXIMATE INVERSE PRECONDITIONING FOR THE CONJUGATE GRADIENT METHOD
Tůma, Miroslav
APPROXIMATE INVERSE PRECONDITIONING FOR THE CONJUGATE GRADIENT METHOD ON A VECTOR COMPUTER Michele definite matrix, by the preconditioned conjugate gradient method (PCG) (see, e.g., [4]). It is well of the conjugate gradient method reduces to computing a matrix vector product with G, an operation which offers
Fast approximation of the bootstrap for model selection
Verleysen, Michel
Fast approximation of the bootstrap for model selection G. Simon1 , A. Lendasse2 , V. Wertz2 , M. The bootstrap resampling method may be efficiently used to estimate the generalization error of a family with the bootstrap in real-world applications is the high computation load. In this paper we propose a simple
Bootstrap for model selection: linear approximation of the optimism
Verleysen, Michel
Bootstrap for model selection: linear approximation of the optimism G. Simon1 , A. Lendasse2 , M. Lemaître 4, B-1348 Louvain-la-Neuve, Belgium, lendasse@auto.ucl.ac.be Abstract. The bootstrap resampling, as artificial neural networks. Nevertheless, the use of the bootstrap implies a high computational load
Approximating many-body induction to efficiently describe molecular liquids
Herbert, John
on the structure and solvation dynamics of the excess electron (in the ground state) but does have a large impact as the structures and properties of molecular systems. This study focuses on approximating many-body electronic methods in order to allow "on-the-fly" energy and force evaluations in dynamical calculations
3-D cinematography with approximate and no geometry
Magnor, Marcus
3-D cinematography with approximate and no geometry Martin Eisemann, Timo Stich and Marcus Magnor Abstract 3-D cinematography is a new step towards full immersive video, allow- ing complete control of the book Image and Geometry Processing for 3-D Cinematography published by Springer. 1 Introduction
A COMPUTATONAL METHOD FOR APPROXIMATING A DARCY-STOKES SYSTEM
Arbogast, Todd
of a second order elliptic (i.e., Darcy) equation on part of the domain coupled to a Stokes equation equation representing Darcy's law and mass conservation, and in the vugs s = \\ Żd by the Stokes equationA COMPUTATONAL METHOD FOR APPROXIMATING A DARCY-STOKES SYSTEM GOVERNING A VUGGY POROUS MEDIUM TODD
Accelerating Search of Approximate Match on Large Protein Sequence Databases
Wang, Wei
of supporting indexed search on large biological sequence databases since the construction cost of the index Yang 2 , Yi Xia 3 , Philip Yu 4 Keywords: protein sequence index, approximate match. Due. Building an appropriate index structure is one of the possibilities to achieve such a goal, which
Local RBF Approximation for Scattered Data Fitting with Bivariate Splines
Davydov, Oleg
and large scale optimization problems arising if the interpolating, smoothing or minimal energy spline in [5], a hybrid polynomial/radial basis scheme was considered in [4], where the local knot locations of radial basis functions, so defining hybrid approximations which are still computed by discrete least
How Synchronisation Strategy Approximation in PEPA Implementations affects Passage Time
Imperial College, London
time densities and dis- tributions from stochastic models defined in PEPA, a stochastic process algebra. In stochastic process algebras, the synchronisation policy is important for defin- ing how different system;good approximation to underlying aggregate complex but deterministic dynamics or genuine random
How Synchronisation Strategy Approximation in PEPA Implementations affects Passage Time
Bradley, Jeremy
passage time densities and dis tributions from stochastic models defined in PEPA, a stochastic process algebra. In stochastic process algebras, the synchronisation policy is important for defin ing how, or a #12; good approximation to underlying aggregate complex but deterministic dynamics or genuine random
Aqua: A Fast Decision Support System Using Approximate Query Answers
Gibbons, Phillip B.
commercial relational DBMS. Aqua precomputes synopses (special sta- tistical summaries) of the original data and stores them in the DBMS. It provides approximate an- swers (with quality guarantees) by rewriting on top of any SQL- compliant DBMS managing a data warehouse. Aqua pre- computes statistical summaries
Jitter-Approximation Tradeoff for Periodic Scheduling Zvika Brakerski
Patt-Shamir, Boaz
Jitter-Approximation Tradeoff for Periodic Scheduling Zvika Brakerski Dept. of Electrical the average period of a job in the schedule is blown up w.r.t. its requested period, and the jitter ratio with low jitter ratio allow the mobile devices to save power by hav- ing their receivers switched off
NUMERICAL APPROXIMATION OF P-SYSTEMS WITH COULOMB FRICTIONAL DAMPING
to the precise nature of the dissipation. Dry (Coulomb) friction is a limit case that has not been fully analyzed in the presence of dry Coulomb friction. A model is described in detail in Section 2. A discretizationNUMERICAL APPROXIMATION OF P-SYSTEMS WITH COULOMB FRICTIONAL DAMPING KRISTY COFFEY AND PIERRE A
Successive Rank-One Approximations of Nearly Orthogonally ...
2015-03-01T23:59:59.000Z
Mar 1, 2015 ... approximating SROA based on the power iteration method of [DLDMV00]. There ... perturbation E is sufficiently small (roughly on the order of 1/n under a natural measure). ... A real p-th order n-dimensional tensor ? ? ? p. R.
Clustering With or Without the Approximation Frans Schalekamp
Schalekamp, Frans
Clustering With or Without the Approximation Frans Schalekamp ITCS, Tsinghua University Michael Yu MIT Anke van Zuylen ITCS, Tsinghua University Abstract We study algorithms for clustering data if we do not know values of and for which the assumption holds. Finally, we implement these methods
Approximate Inference in Probabilistic Models Manfred Opper1
of Electronics and Computer Science University of Southampton SO17 1BJ, United Kingdom mo@ecs.soton.ac.uk 2 on free energies. The free energy is constructed from two approximating distributions which encode differ Energy (GFE), an entropic quantity which (originally developed in Statistical Physics) allows us
The Exemplar Breakpoint Distance for nontrivial genomes cannot be approximated
Fertin, Guillaume
The Exemplar Breakpoint Distance for nonÂtrivial genomes cannot be approximated Guillaume Blin 1 Â France guillaume.fertin@univÂnantes.fr Abstract. A promising and active field of comparative genomics conÂ sists in comparing two genomes by establishing a oneÂtoÂone corresponÂ dence (i.e., a matching) between
Self-similar and charged spheres in the diffusion approximation
W. Barreto; A. Da Silva
2005-08-12T23:59:59.000Z
We study spherical, charged and self--similar distributions of matter in the diffusion approximation. We propose a simple, dynamic but physically meaningful solution. For such a solution we obtain a model in which the distribution becomes static and changes to dust. The collapse is halted with damped mass oscillations about the absolute value of the total charge.
Securely Computing an Approximate Median in Wireless Sensor Networks
Setia, Sanjeev
Securely Computing an Approximate Median in Wireless Sensor Networks Sankardas Roy 1 sroy1@gmu and the unattended nature of sensor nodes, sensor network protocols need to be designed with security in mind and efficient. Categories and Subject Descriptors C.2.0 [Computer-Communication Networks]: General- Security
Cross sections for electron scattering by propane in the low- and intermediate-energy ranges
Souza, G. L. C. de; Lee, M.-T.; Sanches, I. P.; Rawat, P.; Iga, I.; Santos, A. S. dos; Machado, L. E.; Sugohara, R. T.; Brescansin, L. M.; Homem, M. G. P.; Lucchese, R. R. [Departamento de Quimica, UFSCar, 13565-905 Sao Carlos, SP (Brazil); Departamento de Fisica, UFSCar, 13565-905 Sao Carlos, SP (Brazil); Instituto de Fisica 'Gleb Wataghin', UNICAMP, 13083-970 Campinas, SP (Brazil); Departamento de Fisica, UFSC, 88010-970 Florianopolis, SC (Brazil); Department of Chemistry, Texas A and M University, College Station, Texas 7784-3255 (United States)
2010-07-15T23:59:59.000Z
We present a joint theoretical-experimental study on electron scattering by propane (C{sub 3}H{sub 8}) in the low- and intermediate-energy ranges. Calculated elastic differential, integral, and momentum transfer as well as total (elastic + inelastic) and total absorption cross sections are reported for impact energies ranging from 2 to 500 eV. Also, experimental absolute elastic cross sections are reported in the 40- to 500-eV energy range. A complex optical potential is used to represent the electron-molecule interaction dynamics. A theoretical method based on the single-center-expansion close-coupling framework and corrected by the Pade approximant is used to solve the scattering equations. The experimental angular distributions of the scattered electrons are converted to absolute cross sections using the relative flow technique. The comparison of our calculated with our measured results, as well as with other experimental and theoretical data available in the literature, is encouraging.
Ultra High Mass Range Mass Spectrometer System
Reilly, Peter T. A. [Knoxville, TN
2005-12-06T23:59:59.000Z
Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.
Short Range Correlations and the EMC Effect
L.B. Weinstein, E. Piasetzky, D.W. Higinbotham, J. Gomez, O. Hen, R. Shneor
2011-02-01T23:59:59.000Z
This Letter shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering at intermediate xB, 0.35?xB?0.7, is linearly related to the short range correlation (SRC) scale factor obtained from electron inclusive scattering at xB?1. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free pn pair cross sections and F2n/F2p, the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.
Short Range Correlations and the EMC Effect
L. B. Weinstein; E. Piasetzky; D. W. Higinbotham; J. Gomez; O. Hen; R. Shneor
2011-01-18T23:59:59.000Z
This paper shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) at intermediate $x_B$, $0.35\\le x_B\\le 0.7$, is linearly related to the Short Range Correlation (SRC) scaling factor obtained from electron inclusive scattering at $x_B\\ge 1.$. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free $pn$ pair cross sections, the DIS cross section for a free neutron, and $F_2^n/F_2^p$, the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.
Short Range Correlations and the EMC Effect
Weinstein, L. B. [Old Dominion University, Norfolk, Virginia 23529 (United States); Piasetzky, E.; Hen, O.; Shneor, R. [Tel Aviv University, Tel Aviv 69978 (Israel); Higinbotham, D. W.; Gomez, J. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
2011-02-04T23:59:59.000Z
This Letter shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering at intermediate x{sub B}, 0.35{<=}x{sub B{<=}}0.7, is linearly related to the short range correlation (SRC) scale factor obtained from electron inclusive scattering at x{sub B{>=}}1. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free pn pair cross sections and F{sub 2}{sup n}/F{sub 2}{sup p}, the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.
Range Sustainability (VSP) PNWD-SA-7032 1
Range Sustainability (VSP) PNWD-SA-7032 1 PNWD-SA-7032 Range Sustainability Module Using Visual Sample Plan (VSP) Software Range Sustainability ModuleRange Sustainability Module Using Visual Sample Sustainability (VSP) PNWD-SA-7032 2 PNWD-SA-7032 / 2 ObjectiveObjectiveObjective Learn how to use the Range
On approximate controllability of generalized KdV solitons
Claudio Muńoz
2014-05-24T23:59:59.000Z
We consider the approximate control of solitons in generalized Korteweg-de Vries equations. By introducing a suitable internal bilinear control on the equation, we prove that any soliton is locally null controllable, and moreover, any soliton can be accelerated to any particular positive velocity, after a suitable large amount of time. Precise estimates on the error terms and the rate of decay in the approximate null controllability result are also given. Our method introduces a new insight on the control of nonlinear objects, from the point of view of interaction and collision problems for nonlinear dispersive equations, recently developed by Y. Martel and F. Merle. It can be applied in principle, to several other models with soliton solutions.
Exploring approximations to the GW self-energy ionic gradients
Faber, C; Attaccalite, C; Cannuccia, E; Duchemin, I; Deutsch, T; Blase, X
2015-01-01T23:59:59.000Z
The accuracy of the many-body perturbation theory GW formalism to calculate electron-phonon coupling matrix elements has been recently demonstrated in the case of a few important systems. However, the related computational costs are high and thus represent strong limitations to its widespread application. In the present study, we explore two less demanding alternatives for the calculation of electron-phonon coupling matrix elements on the many-body perturbation theory level. Namely, we test the accuracy of the static Coulomb-hole plus screened-exchange (COHSEX) approximation and further of the constant screening approach, where variations of the screened Coulomb potential W upon small changes of the atomic positions along the vibrational eigenmodes are neglected. We find this latter approximation to be the most reliable, whereas the static COHSEX ansatz leads to substantial errors. Our conclusions are validated in a few paradigmatic cases: diamond, graphene and the C60 fullerene. These findings open the way f...
On the Peterlin approximation for turbulent flows of polymer solutions
Dario Vincenzi; Prasad Perlekar; Luca Biferale; Federico Toschi
2015-05-26T23:59:59.000Z
We study the impact of the Peterlin approximation on the statistics of the end-to-end separation of poly- mers in a turbulent flow. The FENE and FENE-P models are numerically integrated along a large number of Lagrangian trajectories resulting from a direct numerical simulation of three-dimensional homogeneous isotropic turbulence. Although the FENE-P model yields results in qualitative agreement with those of the FENE model, quantitative differences emerge. The steady-state probability of large extensions is overesti- mated by the FENE-P model. The alignment of polymers with the eigenvectors of the rate-of-strain tensor and with the direction of vorticity is weaker when the Peterlin approximation is used. At large Weissenberg numbers, both the correlation times of the extension and of the orientation of polymers are underestimated by the FENE-P model.
On the Peterlin approximation for turbulent flows of polymer solutions
Vincenzi, Dario; Biferale, Luca; Toschi, Federico
2015-01-01T23:59:59.000Z
We study the impact of the Peterlin approximation on the statistics of the end-to-end separation of poly- mers in a turbulent flow. The FENE and FENE-P models are numerically integrated along a large number of Lagrangian trajectories resulting from a direct numerical simulation of three-dimensional homogeneous isotropic turbulence. Although the FENE-P model yields results in qualitative agreement with those of the FENE model, quantitative differences emerge. The steady-state probability of large extensions is overesti- mated by the FENE-P model. The alignment of polymers with the eigenvectors of the rate-of-strain tensor and with the direction of vorticity is weaker when the Peterlin approximation is used. At large Weissenberg numbers, both the correlation times of the extension and of the orientation of polymers are underestimated by the FENE-P model.
New Algorithms for Finding Approximate Frequent Item Sets
Berthold, Michael R.
New Algorithms for Finding Approximate Frequent Item Sets Christian Borgelt1 , Christian Braune1,2 , Tobias KÂ¨otter3 and Sonja GrÂ¨un4,5 1 European Centre for Soft Computing c/ Gonzalo GutiÂ´errez QuirÂ´os s/n.borgelt@softcomputing.es, christian.braune@st.ovgu.de, tobias.koetter@uni-konstanz.de, s.gruen@fz-juelich.de Abstract. In standard
Product-state Approximations to Quantum Ground States
Fernando G. S. L. Brandăo; Aram W. Harrow
2014-12-15T23:59:59.000Z
The local Hamiltonian problem consists of estimating the ground-state energy (given by the minimum eigenvalue) of a local quantum Hamiltonian. First, we show the existence of a good product-state approximation for the ground-state energy of 2-local Hamiltonians with one or more of the following properties: (1) high degree, (2) small expansion, or (3) a ground state with sublinear entanglement with respect to some partition into small pieces. The approximation based on degree is a surprising difference between quantum Hamiltonians and classical CSPs (constraint satisfaction problems), since in the classical setting, higher degree is usually associated with harder CSPs. The approximation based on low entanglement, in turn, was previously known only in the regime where the entanglement was close to zero. Since the existence of a low-energy product state can be checked in NP, the result implies that any Hamiltonian used for a quantum PCP theorem should have: (1) constant degree, (2) constant expansion, (3) a "volume law" for entanglement with respect to any partition into small parts. Second, we show that in several cases, good product-state approximations not only exist, but can be found in polynomial time: (1) 2-local Hamiltonians on any planar graph, solving an open problem of Bansal, Bravyi, and Terhal, (2) dense k-local Hamiltonians for any constant k, solving an open problem of Gharibian and Kempe, and (3) 2-local Hamiltonians on graphs with low threshold rank, via a quantum generalization of a recent result of Barak, Raghavendra and Steurer. Our work introduces two new tools which may be of independent interest. First, we prove a new quantum version of the de Finetti theorem which does not require the usual assumption of symmetry. Second, we describe a way to analyze the application of the Lasserre/Parrilo SDP hierarchy to local quantum Hamiltonians.
Studies in Interpolation and Approximation of Multivariate Bandlimited Functions
Bailey, Benjamin Aaron
2012-10-19T23:59:59.000Z
&M University in partial ful llment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Co-Chairs of Committee, Thomas Schlumprecht N. Sivakumar Committee Members, Joel Zinn William Johnson Fred Dahm Head of Department, Albert...{Chairs of Advisory Committee: Dr. Thomas Schlumprecht Dr. N. Sivakumar The focus of this dissertation is the interpolation and approximation of multi- variate bandlimited functions via sampled (function) values. The rst set of results investigates polynomial...
Como, Giacomo
Automating efficiency-targeted approximations in modelling and simulation tools: dynamic decoupling (classical) efficiency-targeted approximation tech- niques, within a unified framework. Some application
The periodic standing-wave approximation: post-Minkowski computation
Christopher Beetle; Benjamin Bromley; Napoleón Hernández; Richard H. Price
2007-08-08T23:59:59.000Z
The periodic standing wave method studies circular orbits of compact objects coupled to helically symmetric standing wave gravitational fields. From this solution an approximation is extracted for the strong field, slowly inspiralling motion of black holes and binary stars. Previous work on this model has dealt with nonlinear scalar models, and with linearized general relativity. Here we present the results of the method for the post-Minkowski (PM) approximation to general relativity, the first step beyond linearized gravity. We compute the PM approximation in two ways: first, via the standard approach of computing linearized gravitational fields and constructing from them quadratic driving sources for second-order fields, and second, by solving the second-order equations as an ``exact'' nonlinear system. The results of these computations have two distinct applications: (i) The computational infrastructure for the ``exact'' PM solution will be directly applicable to full general relativity. (ii) The results will allow us to begin supplying initial data to collaborators running general relativistic evolution codes.
Synergy between Secondary Organic Aerosols and Long Range Transport...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
between Secondary Organic Aerosols and Long Range Transport of Polycyclic Aromatic Hydrocarbons. Synergy between Secondary Organic Aerosols and Long Range Transport of Polycyclic...
Molecular dynamics simulations of ion range profiles for heavy...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
simulations of ion range profiles for heavy ions in light targets. Molecular dynamics simulations of ion range profiles for heavy ions in light targets. Abstract: The determination...
Numerical Modeling of Transient Basin and Range Extensional Geothermal...
behavior of basin and range extensionalgeothermal systems, and particularly, the evolution ofthe system temperature with time. Each modelconsists of two mountain ranges (1 km...
Teleseismic-Seismic Monitoring At Nw Basin & Range Region (Biasi...
Teleseismic-Seismic Monitoring At Nw Basin & Range Region (Biasi, Et Al., 2008) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration...
Teleseismic-Seismic Monitoring At Nw Basin & Range Region (Biasi...
Teleseismic-Seismic Monitoring At Nw Basin & Range Region (Biasi, Et Al., 2009) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration...
Cluster formation in fluids with competing short-range and long-range interactions
Sweatman, Martin B., E-mail: martin.sweatman@ed.ac.uk; Fartaria, Rui [Institute of Materials and Processes, School of Engineering, University of Edinburgh, Edinburgh EH9 3JL (United Kingdom)] [Institute of Materials and Processes, School of Engineering, University of Edinburgh, Edinburgh EH9 3JL (United Kingdom); Lue, Leo [Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom)] [Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom)
2014-03-28T23:59:59.000Z
We investigate the low density behaviour of fluids that interact through a short-ranged attraction together with a long-ranged repulsion (SALR potential) by developing a molecular thermodynamic model. The SALR potential is a model of effective solute interactions where the solvent degrees of freedom are integrated-out. For this system, we find that clusters form for a range of interaction parameters where attractive and repulsive interactions nearly balance, similar to micelle formation in aqueous surfactant solutions. We focus on systems for which equilibrium behaviour and liquid-like clusters (i.e., droplets) are expected, and find in addition a novel coexistence between a low density cluster phase and a high density cluster phase within a very narrow range of parameters. Moreover, a simple formula for the average cluster size is developed. Based on this formula, we propose a non-classical crystal nucleation pathway whereby macroscopic crystals are formed via crystal nucleation within microscopic precursor droplets. We also perform large-scale Monte Carlo simulations, which demonstrate that the cluster fluid phase is thermodynamically stable for this system.
Numerical Algorithms 16 (1997) 115 1 Sparse approximate inverse preconditioning
Benzi, Michele
propagation phenomena to address various topics ranging from electromagnetic compatibility, to stealth, to absorbing materials, and antenna de- sign. Two complementary approaches based on the solution of the Maxwell
Thermally-assisted-occupation density functional theory with generalized-gradient approximations
Chai, Jeng-Da, E-mail: jdchai@phys.ntu.edu.tw [Department of Physics, Center for Theoretical Sciences, and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)] [Department of Physics, Center for Theoretical Sciences, and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)
2014-05-14T23:59:59.000Z
We extend the recently proposed thermally-assisted-occupation density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] to generalized-gradient approximation (GGA) exchange-correlation density functionals. Relative to our previous TAO-LDA (i.e., the local density approximation to TAO-DFT), the resulting TAO-GGAs are significantly superior for a wide range of applications, such as thermochemistry, kinetics, and reaction energies. For noncovalent interactions, TAO-GGAs with empirical dispersion corrections are shown to yield excellent performance. Due to their computational efficiency for systems with strong static correlation effects, TAO-LDA and TAO-GGAs are applied to study the electronic properties (e.g., the singlet-triplet energy gaps, vertical ionization potentials, vertical electron affinities, fundamental gaps, and symmetrized von Neumann entropy) of acenes with different number of linearly fused benzene rings (up to 100), which is very challenging for conventional electronic structure methods. The ground states of acenes are shown to be singlets for all the chain lengths studied here. With the increase of acene length, the singlet-triplet energy gaps, vertical ionization potentials, and fundamental gaps decrease monotonically, while the vertical electron affinities and symmetrized von Neumann entropy (i.e., a measure of polyradical character) increase monotonically.
Nayak, A.K. [Bhaha Atomic Research Centre (India); Aritomi, M. [Tokyo Institute of Technology (Japan); Raj, V. Venkat [Bhaha Atomic Research Centre (India)
2001-07-15T23:59:59.000Z
The coupled neutronic-thermohydraulic stability characteristics of a natural circulation heavy water-moderated boiling light water-cooled reactor was investigated analytically considering the effects of prompt and delayed neutrons. For this purpose, the reactor considered is the Indian Advanced Heavy Water Reactor. The analytical model considers a point kinetics model for the neutron dynamics, a homogeneous two-phase flow model for the coolant thermal hydraulics, and a lumped heat transfer model for the fuel thermal dynamics. A higher mode of oscillation having a frequency much greater than the density-wave oscillation frequency was observed if prompt neutrons alone were considered. The occurrence of a higher mode of oscillation was found to be dependent on the concentration of delayed neutrons, the void reactivity coefficient, and the fuel time constant. The core inlet subcooling is found to have different effects on the decay ratio of the fundamental and higher modes of oscillations. The influences of void reactivity coefficient and fuel time constant on the fundamental and higher modes of oscillations were also found to be opposite in nature.
Nutritional Value of Range Plants in Edwards Plateau Region of Texas.
Huston, J.E.; Rector, B.S.; Merrill, L.B.; Engdahl, B.S.
1981-01-01T23:59:59.000Z
Concentrati~n(%)~ Id Number of Season Observations Water C.P. D.O.M. P Spring 23 61 a 13" 50' .17' Summer 21 48' 8" 39" .ma Fall 2 e .- 52' 1 0' 41 a .13" Winter 17' 46' 10' 44" .12',~ @dudes approximately equal observations from: Texas Wintemrass... ..I.. - - .,, ....- , ";', ..', A - , .l. ,.l.. .I. ,I.. * "'" "'f. - .IS. of Range P in the Edwards P ateau Regicin of Texas' The Texas A&M Unlvenitv SysternoTlle Texas Agricultural Emriment Station * w l l l e P. Clarke. Director *College...
Transition to Chaos in Discrete Nonlinear Schrodinger Equation with Long-Range Interaction
Nickolay Korabel; George M. Zaslavsky
2006-08-15T23:59:59.000Z
Discrete nonlinear Schrodinger equation (DNLS) describes a chain of oscillators with nearest neighbor interactions and a specific nonlinear term. We consider its modification with long-range interaction through a potential proportional to $1/l^{1+\\alpha}$ with fractional $\\alpha transition to chaos in this system as a function of $\\alpha$ and nonlinearity. It is shown that decreasing of $\\alpha$ with respect to nonlinearity stabilize the system. Connection of the model to the fractional genezalization of the NLS (called FNLS) in the long-wave approximation is also discussed and some of the results obtained for $\\alpha$DNLS can be correspondingly extended to the FNLS.
Bond, Stephen D.
2014-01-01T23:59:59.000Z
The availability of efficient algorithms for long-range pairwise interactions is central to the success of numerous applications, ranging in scale from atomic-level modeling of materials to astrophysics. This report focuses on the implementation and analysis of the multilevel summation method for approximating long-range pairwise interactions. The computational cost of the multilevel summation method is proportional to the number of particles, N, which is an improvement over FFTbased methods who's cost is asymptotically proportional to N logN. In addition to approximating electrostatic forces, the multilevel summation method can be use to efficiently approximate convolutions with long-range kernels. As an application, we apply the multilevel summation method to a discretized integral equation formulation of the regularized generalized Poisson equation. Numerical results are presented using an implementation of the multilevel summation method in the LAMMPS software package. Preliminary results show that the computational cost of the method scales as expected, but there is still a need for further optimization.
POLYGENETIC TOPOGRAPHY OF THE CASCADE RANGE, WASHINGTON STATE, USA
-relief topography, 2) post-Miocene surface uplift of the range superimposed on pre-existing high-relief topographyPOLYGENETIC TOPOGRAPHY OF THE CASCADE RANGE, WASHINGTON STATE, USA SARA GRAN MITCHELL Range of Washington State by analyzing the topography, geology, and exhumation patterns across the range