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Sample records for reversed extension flow

  1. Reversed Extension Flow of Polymer melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Nielsen, Jens Kromann

    2007-01-01

    The measurement of the startup of uni axial elongational flow (potentially until steady state) followed by reversed bi axial flow, both with a constant elongational rate was made possible using a Filament Stretching Rheometer (FSR). The filament stretching rheometer rheometer is surrounded...... by a thermostated environment and allows measurements on polymeric melts and liquids from room temperatures until 200 °C. In the experiments the Hencky strain at which the stress becomes zero (the recovery strain) of the reversed flow can be identified....

  2. Modified and reverse radiometric flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Ba, H; Khin, M M; Aung, K; Thida, [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-06-01

    Determination of [sup 137]Cs and [sup 60]Co by using modified and reverse radiometric flow injection analysis is described. Two component RFIA was also realized using [sup 60]Co and [sup 137]Cs radionuclides. (author) 2 refs.; 5 figs.

  3. C*-algebras associated with reversible extensions of logistic maps

    International Nuclear Information System (INIS)

    Kwaśniewski, Bartosz K

    2012-01-01

    The construction of reversible extensions of dynamical systems presented in a previous paper by the author and A.V. Lebedev is enhanced, so that it applies to arbitrary mappings (not necessarily with open range). It is based on calculating the maximal ideal space of C*-algebras that extends endomorphisms to partial automorphisms via partial isometric representations, and involves a new set of 'parameters' (the role of parameters is played by chosen sets or ideals). As model examples, we give a thorough description of reversible extensions of logistic maps and a classification of systems associated with compression of unitaries generating homeomorphisms of the circle. Bibliography: 34 titles.

  4. C*-algebras associated with reversible extensions of logistic maps

    Science.gov (United States)

    Kwaśniewski, Bartosz K.

    2012-10-01

    The construction of reversible extensions of dynamical systems presented in a previous paper by the author and A.V. Lebedev is enhanced, so that it applies to arbitrary mappings (not necessarily with open range). It is based on calculating the maximal ideal space of C*-algebras that extends endomorphisms to partial automorphisms via partial isometric representations, and involves a new set of 'parameters' (the role of parameters is played by chosen sets or ideals). As model examples, we give a thorough description of reversible extensions of logistic maps and a classification of systems associated with compression of unitaries generating homeomorphisms of the circle. Bibliography: 34 titles.

  5. Flooding and flow reversal of two-phase annular flow

    International Nuclear Information System (INIS)

    Asahi, Y.

    1978-01-01

    The flooding and flow reversal conditions of two-phase annular flow are mathematically defined in terms of a characteristic function representing a force balance. Sufficiently below the flooding point in counter-current flow, the interface is smooth and the characteristic equation reduces to the Nusselt relationship. Just below flooding point and above the flow reversal point in cocurrent flow, the interface is 'wavy', so that the interfacial shear effect plays an important role. The theoretical analysis is compared with experimental results by others. It is suggested that the various length effects which have been experimentally observed may be accounted for by the spatial variation of the droplet entrainment. (Auth.)

  6. Fuel bundle movement due to reverse flow

    Energy Technology Data Exchange (ETDEWEB)

    Wahba, N N; Akalin, O [Ontario Hydro, Toronto, ON (Canada)

    1996-12-31

    When a break occurs in the inlet feeder or inlet header, the rapid depressurization will cause the channel flow to reverse forcing the string of bundles to accelerate and impact with upstream shield plug. A model has been developed to predict the bundle motion due to the channel flow reversal. The model accounts for various forces acting on the bundle. A series of five reverse flow, bundle acceleration experiments have been conducted simulating a break in the inlet feeder of a CANDU fuel channel. The model has been validated against the experiments. The predicted impact velocities are in good agreement with the measured values. It is demonstrated that the model may be successfully used in predicting bundle relocation timing following a large LOCA (loss of coolant). (author). 7 refs., 3 tabs., 11 figs.

  7. Investigations on flow reversal in stratified horizontal flow

    International Nuclear Information System (INIS)

    Staebler, T.; Meyer, L.; Schulenberg, T.; Laurien, E.

    2005-01-01

    The phenomena of flow reversal in stratified flows are investigated in a horizontal channel with application to the Emergency Core Cooling System (ECCS) in Pressurized Water Reactors (PWR). In case of a Loss-of-Coolant-Accident (LOCA), coolant can be injected through a secondary pipe within the feeding line of the primary circuit, the so called hot leg, counter-currently to the steam flow. It is essential that the coolant reaches the reactor core to prevent overheating. Due to high temperatures in such accident scenarios, steam is generated in the core, which escapes from the reactor vessel through the hot leg. In case of sufficiently high steam flow rates, only a reduced amount of coolant or even no coolant will be delivered to the reactor core. The WENKA test facility at the Institute for Nuclear and Energy Technologies (IKET) at Forschungszentrum Karlsruhe is capable to investigate the fluid dynamics of two-phase flows in such scenarios. Water and air flow counter-currently in a horizontal channel made of clear acrylic glass to allow full optical access. Flow rates of water and air can be varied independently within a wide range. Once flow reversal sets in, a strong hysteresis effect must be taken into account. This was quantified during the present investigations. Local experimental data are needed to expand appropriate models on flow reversal in horizontal two-phase flow and to include them into numerical codes. Investigations are carried out by means of Particle Image Velocimetry (PIV) to obtain local flow velocities without disturbing the flow. Due to the wavy character of the flow, strong reflections at the interfacial area must be taken into account. Using fluorescent particles and an optical filter allows eliminating the reflections and recording only the signals of the particles. The challenges in conducting local investigations in stratified wavy flows by applying optical measurement techniques are discussed. Results are presented and discussed allowing

  8. Flow reversal power limit for the HFBR

    International Nuclear Information System (INIS)

    Cheng, L.Y.; Tichler, P.R.

    1997-01-01

    The High Flux Beam Reactor (HFBR) is a pressurized heavy water moderated and cooled research reactor that began operation at 40 MW. The reactor was subsequently upgraded to 60 MW and operated at that level for several years. The reactor undergoes a buoyancy-driven reversal of flow in the reactor core following certain postulated accidents. Questions which were raised about the afterheat removal capability during the flow reversal transition led to a reactor shutdown and subsequent resumption of operation at a reduced power of 30 MW. An experimental and analytical program to address these questions is described in this report. The experiments were single channel flow reversal tests under a range of conditions. The analytical phase involved simulations of the tests to benchmark the physical models and development of a criterion for dryout. The criterion is then used in simulations of reactor accidents to determine a safe operating power level. It is concluded that the limit on the HFBR operating power with respect to the issue of flow reversal is in excess of 60 MW. Direct use of the experimental results and an understanding of the governing phenomenology supports this conclusion

  9. On flow reversals in Rayleigh-Bénard convection

    International Nuclear Information System (INIS)

    Chandra, Mani; Verma, Mahendra K

    2011-01-01

    The dynamics of flow reversals are studied numerically using Fourier mode analysis. Our analysis shows that the Fourier modes represent the large-scale flows accurately. We observe that during the reversals, the amplitude of one of the large-scale modes vanishes, while another mode rises sharply, very similar to the cessation-led reversals observed earlier in experiments and numerical simulations. The Fourier coefficients of the RBC equations obey certain symmetries properties, which dictates which modes change sign in flow reversals. Based on our simulation results and symmetry properties of the Fourier modes, we provide a qualitative explanation for the flow reversals.

  10. Reducing the memory requirement in reverse mode automatic differentiation by solving TBR flow equations

    International Nuclear Information System (INIS)

    Naumann, U.

    2002-01-01

    The fast computation of gradients in reverse mode Automatic Differentiation (AD) requires the generation of adjoint versions of every statement in the original code. Due to the resulting reversal of the control flow certain intermediate values have to be made available in reverse order to compute the local partial derivatives. This can be achieved by storing these values or by recomputing them when they become required. In any case one is interested in minimizing the size of this set. Following an extensive introduction of the ''To-Be-Recorded'' (TBR) problem the authors present flow equations for propagating the TBR status of variables in the context of reverse mode AD of structured programs

  11. High Pressure Reverse Flow APS Engine

    Science.gov (United States)

    Senneff, J. M.

    1972-01-01

    A design and test demonstration effort was undertaken to evaluate the concept of the reverse flow engine for the APS engine application. The 1500 lb (6672 N) thrust engine was designed to operate on gaseous hydrogen and gaseous oxygen propellants at a mixture ratio of 4 and to achieve the objective performance of 435 sec (4266 Nsec/kg) specific impulse. Superimposed durability requirements called for a million-cycle capability with 50 hours duration. The program was undertaken as a series of tasks including the initial preliminary design, design of critical test components and finally, the design and demonstration of an altitude engine which could be used interchangeably to examine operating parameters as well as to demonstrate the capability of the concept. The program results are reported with data to indicate that all of the program objectives were met or exceeded within the course of testing on the program. The analysis effort undertaken is also reported in detail and supplemented with test data in some cases where prior definitions could not be made. The results are contained of these analyses as well as the test results conducted throughout the course of the program. Finally, the test data and analytical results were combined to allow recommendations for a flight weight design. This preliminary design effort is also detailed.

  12. ON THE ANALYSIS OF IMPEDANCE-DRIVEN REVERSE FLOW DYNAMICS

    Directory of Open Access Journals (Sweden)

    LEE V. C.-C.

    2017-02-01

    Full Text Available Impedance pump is a simple valve-less pumping mechanism, where an elastic tube is joined to a more rigid tube, at both ends. By inducing a periodic asymmetrical compression on the elastic tube will produce a unidirectional flow within the system. This pumping concept offers a low energy, low noise alternative, which makes it an effective driving mechanism, especially for micro-fluidic systems. In addition, the wave-based mechanism through which pumping occurs infers many benefits in terms of simplicity of design and manufacturing. Adjustment of simple parameters such as the excitation frequencies or compression locations will reverse the direction of flow, providing a very versatile range of flow outputs. This paper describes the experimental analysis of such impedance-driven flow with emphasis on the dynamical study of the reverse flow in open-loop environment. In this study, tapered section with converging steps is introduced at both ends of the elastic tube to amplify the magnitude of reverse flow. Study conducted shows that the reverse peak flow is rather significant with estimate of 23% lower than the forward peak flow. The flow dynamics on the other hand has shown to exhibit different characteristics as per the forward peak flow. The flow characteristics is then studied and showed that the tapered sections altered the impedance within the system and hence induce a higher flow in the reverse direction.

  13. Fuel bundle impact velocities due to reverse flow

    International Nuclear Information System (INIS)

    Wahba, N.N.; Locke, K.E.

    1996-01-01

    If a break should occur in the inlet feeder or inlet header of a CANDU reactor, the rapid depressurization will cause the channel flow(s) to reverse. Depending on the gap between the upstream bundle and shield plug, the string of bundles will accelerate in the reverse direction and impact with the upstream shield plug. The reverse flow impact velocities have been calculated for various operating states for the Bruce NGS A reactors. The sensitivity to several analysis assumptions has been determined. (author)

  14. Transition of unsteady velocity profiles with reverse flow

    OpenAIRE

    Das, Debopam; Arakeri, Jaywant H

    1998-01-01

    This paper deals with the stability and transition to turbulence of wall-bounded unsteady velocity profiles with reverse flow. Such flows occur, for example, during unsteady boundary layer separation and in oscillating pipe flow. The main focus is on results from experiments in time-developing flow in a long pipe, which is decelerated rapidly. The flow is generated by the controlled motion of a piston. We obtain analytical solutions for laminar flow in the pipe and in a two-dimensional channe...

  15. Local particle flux reversal under strongly sheared flow

    International Nuclear Information System (INIS)

    Terry, P.W.; Newman, D.E.; Ware, A.S.

    2003-01-01

    The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

  16. Reverse Flow Engine Core Having a Ducted Fan with Integrated Secondary Flow Blades

    Science.gov (United States)

    Kisska, Michael K. (Inventor); Princen, Norman H. (Inventor); Kuehn, Mark S. (Inventor); Cosentino, Gary B. (Inventor)

    2014-01-01

    Secondary air flow is provided for a ducted fan having a reverse flow turbine engine core driving a fan blisk. The fan blisk incorporates a set of thrust fan blades extending from an outer hub and a set of integral secondary flow blades extending intermediate an inner hub and the outer hub. A nacelle provides an outer flow duct for the thrust fan blades and a secondary flow duct carries flow from the integral secondary flow blades as cooling air for components of the reverse flow turbine engine.

  17. REVERSE CHARGE AND THE CASH FLOW OF THE PUBLIC BUDGETS IN THE CZECH REPUBLIC

    Directory of Open Access Journals (Sweden)

    Kohoutková Růžena

    2015-12-01

    Full Text Available Reverse charge is currently used as a measure against VAT carousel fraud. Its extension to all goods and services is discussed among the tax policy makers at the national and EU level. Opponents of general reverse-charge argue that this method of VAT collection would completely change the nature of the VAT system. One of the practical drawbacks of reverse charge is the negative impact on the cash flow of the public budgets. This article quantifies the average monthly financing available to the State thanks to delayed repayments of input tax to VAT payers under the normal VAT system. This amount equals to almost 53 billion CZK and represents the negative impact of the general reverse charge on the cash flow of the public budgets. A change in the deadline for remitting VAT or introducing VAT advances to be paid prior to the final tax payment would reduce the negative influence on public finances.

  18. An analytic model for flow reversal in divertor plasmas

    International Nuclear Information System (INIS)

    Cooke, P.I.H.; Prinja, A.K.

    1987-04-01

    An analytic model is developed and used to study the phenomenon of flow reversal which is observed in two-dimensional simulations of divertor plasmas. The effect is shown to be caused by the radial spread of neutral particles emitted from the divertor target which can lead to a strong peaking of the ionization source at certain radial locations. The results indicate that flow reversal over a portion of the width of the scrape-off layer is inevitable in high recycling conditions. Implications for impurity transport and particle removal in reactors are discussed

  19. Remagnetization of lava flows spanning the last geomagnetic reversal

    Science.gov (United States)

    Vella, Jérôme; Carlut, Julie; Valet, Jean-Pierre; Goff, Maxime Le; Soler, Vicente; Lopes, Fernando

    2017-08-01

    Large directional changes of remanent magnetization within lava flows that cooled during geomagnetic reversals have been reported in several studies. A geomagnetic scenario implies extremely rapid geomagnetic changes of several degrees per day, thus difficult to reconcile with the rate of the earth's core liquid motions. So far, no complete rock magnetic model provides a clear explanation. We revisited lava flows sandwiched between an underlying reverse and an overlying normal polarity flow marking the last reversal in three distinct volcanic sequences of the La Palma Island (Canary archipelago, Spain) that are characterized by a gradual evolution of the direction of their remanent magnetization from bottom to top. Cleaning efficiency of thermal demagnetization was not improved by very rapid heating and cooling rates as well as by continuous demagnetization using a Triaxe magnetometer. We did not observe partial self-reversals and minor changes in magnetic grain sizes are not related to the within-flow directional changes. Microscopic observations indicate poor exsolution, which suggests post-cooling thermochemical remagnetization processes. This scenario is strongly reinforced by laboratory experiments that show large resistance to thermal demagnetization when thermoremanence was acquired over a long time period. We speculate that in the present situation exsolution was reactivated during in field reheating and yielded formation of new magnetite, yet magnetic domain state rearrangements could also play a role. Initial reheating when the overlying flow took place, albeit moderate (less than 200-300 °C), was enough to produce overlying components with significantly higher unblocking temperatures.

  20. Transition of unsteady velocity profiles with reverse flow

    Science.gov (United States)

    Das, Debopam; Arakeri, Jaywant H.

    1998-11-01

    This paper deals with the stability and transition to turbulence of wall-bounded unsteady velocity profiles with reverse flow. Such flows occur, for example, during unsteady boundary layer separation and in oscillating pipe flow. The main focus is on results from experiments in time-developing flow in a long pipe, which is decelerated rapidly. The flow is generated by the controlled motion of a piston. We obtain analytical solutions for laminar flow in the pipe and in a two-dimensional channel for arbitrary piston motions. By changing the piston speed and the length of piston travel we cover a range of values of Reynolds number and boundary layer thickness. The velocity profiles during the decay of the flow are unsteady with reverse flow near the wall, and are highly unstable due to their inflectional nature. In the pipe, we observe from flow visualization that the flow becomes unstable with the formation of what appears to be a helical vortex. The wavelength of the instability [simeq R: similar, equals]3[delta] where [delta] is the average boundary layer thickness, the average being taken over the time the flow is unstable. The time of formation of the vortices scales with the average convective time scale and is [simeq R: similar, equals]39/([Delta]u/[delta]), where [Delta]u=(umax[minus sign]umin) and umax, umin and [delta] are the maximum velocity, minimum velocity and boundary layer thickness respectively at each instant of time. The time to transition to turbulence is [simeq R: similar, equals]33/([Delta]u/[delta]). Quasi-steady linear stability analysis of the velocity profiles brings out two important results. First that the stability characteristics of velocity profiles with reverse flow near the wall collapse when scaled with the above variables. Second that the wavenumber corresponding to maximum growth does not change much during the instability even though the velocity profile does change substantially. Using the results from the experiments and the

  1. Mechanism of flow reversal during solidification of an anomalous liquid

    Science.gov (United States)

    Kumar, Virkeshwar; Kumawat, Mitesh; Srivastava, Atul; Karagadde, Shyamprasad

    2017-12-01

    In a wide variety of fluidic systems involving thermal and compositional gradients, local density changes lead to the onset of natural convection that influences the process itself, for example, during phase-change phenomena and magmatic flows. Accurate knowledge of the flow characteristics is essential to quantify the impact of the flow of the processes. In this work, the first-ever demonstration of flow reversal during bottom-up solidification of water using full-field thermal and flow measurements and its direct impact on the solidifying interface is presented. Based on prior optical interferometric measurements of full-field temperature distribution in water during solidification, we use the particle image velocimetry technique to quantify and reveal the changing natural convection pattern arising solely due to the density anomaly of water between 0 °C and 4 °C. The independently captured thermal and flow fields show striking similarities and clearly elucidate the plausible mechanism explaining the formation of a curved interface at the stagnation point and the subsequent reversal of flow direction due to a changed interface morphology. A control volume analysis is further presented to estimate the energy invested in the formation of a perturbation and the resulting flip in the flow direction caused by this perturbation.

  2. L2 Extensive Reading and Flow: Clarifying the Relationship

    Science.gov (United States)

    Kirchhoff, Cheryl

    2013-01-01

    Among foreign language educators interest in extensive reading is growing along with questions about learner motivation to read. Maintaining learner motivation over long periods of time is influenced by many variables suggesting that multiple means of stimulating motivation is needed. The psychological theory of flow has been suggested to…

  3. Flow and Failure in Extension of Monodisperse Polymer Melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.

    is commonly referred to be of either brittle (e.g. cohesive type) or of liquid (e.g. necking type) nature. Here the focus will be on monodisperse polymers, to study numerically the sample flow dynamics in dual wind-up extensional rheometers. The computations are within the ideas of the microstructural......It is well known that failure or rupture phenomenon appears in the extension of polymer melts. These appear not only as failure in extension rheometers, but also as sharkskin, developments of holes in thin polymeric films etc. Sometime these ruptures appear spontaneous as well. The rupture...... 'interchain pressure' theory based on the molecular stress function constitutive model for the polymer melt flow. The purpose is twofold. Primarily to present to what extend the experimentally observed failure, appearing during or after (e.g. as a spontaneous failure) extension, can be explained within...

  4. Turbulence Modeling of Flows with Extensive Crossflow Separation

    Directory of Open Access Journals (Sweden)

    Argyris G. Panaras

    2015-07-01

    Full Text Available The reasons for the difficulty in simulating accurately strong 3-D shock wave/turbulent boundary layer interactions (SBLIs and high-alpha flows with classical turbulence models are investigated. These flows are characterized by the appearance of strong crossflow separation. In view of recent additional evidence, a previously published flow analysis, which attributes the poor performance of classical turbulence models to the observed laminarization of the separation domain, is reexamined. According to this analysis, the longitudinal vortices into which the separated boundary layer rolls up in this type of separated flow, transfer external inviscid air into the part of the separation adjacent to the wall, decreasing its turbulence. It is demonstrated that linear models based on the Boussinesq equation provide solutions of moderate accuracy, while non-linear ones and others that consider the particular structure of the flow are more efficient. Published and new Reynolds Averaged Navier–Stokes (RANS simulations are reviewed, as well as results from a recent Large Eddy Simulation (LES study, which indicate that in calculations characterized by sufficient accuracy the turbulent kinetic energy of the reverse flow inside the separation vortices is very low, i.e., the flow is almost laminar there.

  5. Liquid flow along a solid surface reversibly alters interfacial chemistry.

    Science.gov (United States)

    Lis, Dan; Backus, Ellen H G; Hunger, Johannes; Parekh, Sapun H; Bonn, Mischa

    2014-06-06

    In nature, aqueous solutions often move collectively along solid surfaces (for example, raindrops falling on the ground and rivers flowing through riverbeds). However, the influence of such motion on water-surface interfacial chemistry is unclear. In this work, we combine surface-specific sum frequency generation spectroscopy and microfluidics to show that at immersed calcium fluoride and fused silica surfaces, flow leads to a reversible modification of the surface charge and subsequent realignment of the interfacial water molecules. Obtaining equivalent effects under static conditions requires a substantial change in bulk solution pH (up to 2 pH units), demonstrating the coupling between flow and chemistry. These marked flow-induced variations in interfacial chemistry should substantially affect our understanding and modeling of chemical processes at immersed surfaces. Copyright © 2014, American Association for the Advancement of Science.

  6. Dynamic Behavior of Reverse Flow Reactor for Lean Methane Combustion

    OpenAIRE

    Yogi W. Budhi; M. Effendy; Yazid Bindar; Subagjo

    2014-01-01

    The stability of reactor operation for catalytic oxidation of lean CH4 has been investigated through modeling and simulation, particularly the influence of switching time and heat extraction on reverse flow reactor (RFR) performance. A mathematical model of the RFR was developed, based on one-dimensional pseudo-homogeneous model for mass and heat balances, incorporating heat loss through the reactor wall. The configuration of the RFR consisted of inert-catalyst-inert, with or without heat ext...

  7. Reverse flow through a large scale multichannel nozzle

    International Nuclear Information System (INIS)

    Duignan, M.R.; Nash, C.A.

    1992-01-01

    A database was developed for the flow of water through a scaled nozzle of a Savannah River Site reactor inlet plenum. The water flow in the nozzle was such that it ranged from stratified to water solid conditions. Data on the entry of air into the nozzle and plenum as a function of water flow are of interest in loss-of-coolant studies. The scaled nozzle was 44 cm long, had an entrance diameter of 95 mm, an exit opening of 58 mm x 356 mm, and an exit hydraulic diameter approximately equal to that of the inlet. Within the nozzle were three flow-straightening vanes which divided the flow path into four channels. All data were taken at steady-state and isothermal (300 K ± 1.5 K) conditions. During the reverse flow of water through the nozzle the point at which air begins to enter was predicted within 90% by a critical weir-flow calculation. The point of air entry into the plenum itself was found to be a function of flow conditions

  8. Occurrence of critical heat flux during blowdown with flow reversal

    International Nuclear Information System (INIS)

    Leung, J.C.M.

    1976-04-01

    A small-scale experiment using Freon-11 at 130 0 F and 65 psia in a well-instrumented transparent annular test section was used to study the occurrence of critical heat flux (CHF) during blowdown with flow reversal. The inner stainless steel tube of the annulus was uniformly heated over its 2 ft length. Inlet and exit void fractions were measured by a capacitance technique. Flow regime transition was observed with high speed photography. A 1-hr contact time between Freon-11 and nitrogen at 130 0 F and 60 psig was found to greatly affect the steady-state subcooled boiling initial conditions. Delay in bubble growth was observed in adiabatic blowdown runs. This was caused by the thermodynamic nonequilibrium conditions required for the unstable bubble growth. For the diabatic runs, equilibrium was more closely approached in the test section during the early phase of blowdown. Critical heat flux did not occur immediately during the flow decay in an approximately 60 msec reversal period. The first or early CHF which occurred at about 400 msec was independent of the blowdown volume and did not propagate upward. An annular flow pattern appeared at the onset of this CHF which occurred only at the lower 8 in. of the heated zone

  9. Effect of Flow Channel Shape on Performance in Reverse Electrodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kilsung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Deok Han; Kim, Daejoong [Sogang Univ., Seoul (Korea, Republic of)

    2017-05-15

    Reverse electrodialysis (RED), which generates electrical energy from the difference in concentration of two solutions, has been actively studied owing to its high potential and the increased interest in renewable energy resulting from the Paris Agreement on climate change. For RED commercialization, its power density needs to be maximized, and therefore various methods have been discussed. In this paper, the power density was measured using various flow shapes based on the aspect ratio, opening ratio, and number of distribution channels. We found that the power density is enhanced with a decrease in the aspect ratio and an increase in the opening ratio and number of distribution channels.

  10. Experimental study on fundamental performance of reverse flow diverters

    International Nuclear Information System (INIS)

    Fan Yanfang; Xu Cong; Jing Shan

    2008-01-01

    The Reverse Flow Diverter (RFD) is one of the key components affecting the liquid-delivered efficiency. The effects of inflow structure, outflow structure, area ratio and suction gap on the performance of RFDs were studied in this paper. It can be found experimentally that expected entrainment phenomenon can be achieved when the outlet velocity of fluid for RFDs' inflow structure is sufficient. There is less liquid delivered by an RFD with a long receiver than that without a receiver. Because of back-flow caused by vortex separation, oversize area ratio cannot have better entrainment phenomenon and the optimum area ratio is 1.5. When the ratio of suction gap length to inlet diameter of outflow structure is 0.9-1.0, the excellent liquid-delivered efficiency can be obtained. (authors)

  11. Pioneer 7 observations of plasma flow and field reversal regions in the distant geomagnetic tail

    International Nuclear Information System (INIS)

    Walker, R.C.; Villante, U.; Lazarus, A.J.

    1975-01-01

    We present the results of an extensive analysis of plasma and magnetic field data from Pioneer 7 taken in the geomagnetic tail approximately 1000 R/sub E/ downstream from earth. The principal observations are (1) measurable fluxes of protons in the tail, flowing away from earth, sometimes with a double-peaked velocity distribution; (2) field reversal regions in which the field changes from radial to antiradial by a vector rotation in the north-south plane; and (3) general characteristics of the tail similar to those observed near earth with good correlation between taillike magnetic fields and plasma

  12. Pioneer 7 observations of plasma flow and field reversal regions in the distant geomagnetic tail

    Science.gov (United States)

    Walker, R. C.; Lazarus, A. J.; Villante, U.

    1975-01-01

    The present paper gives the results of an extensive analysis of plasma and magnetic-field data from Pioneer 7 taken in the geomagnetic tail approximately 1000 earth radii downstream from earth. The principal observations are: (1) measurable fluxes of protons in the tail, flowing away from earth, sometimes with a double-peaked velocity distribution; (2) field reversal regions in which the field changes from radial to antiradial by a vector rotation in the north-south plane; and (3) general characteristics of the tail similar to those observed near earth with good correlation between taillike magnetic fields and plasma.

  13. Joint interpretation of two tracer tests with reversed flow fields

    International Nuclear Information System (INIS)

    Kunstmann, H.; Kinzelbach, W.; Marschall, P.; Li, G.

    1995-01-01

    Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic for the breakthrough curves in both experiments. The tests were interpreted using a single fracture flow model. Tracer transport is described by advection/dispersion along the fracture allowing for diffusion into an immobile matrix. The authors were able to interpret the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. The authors conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis suggested that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will cause tailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation

  14. Occurrence of critical heat flux during blowdown with flow reversal

    International Nuclear Information System (INIS)

    Leung, J.C.M.

    1977-01-01

    A small-scale experiment using Freon-11 at 130 0 F (54.4 0 C) and 65 psia (0.45 MPa) in a well-instrumented, transparent annular test section was used to study the occurrence of critical heat flux (CHF) during blowdown with flow reversal. The inner stainless steel tube of the annulus was uniformly heated over its 61-cm length. Inlet and exit void fractions were measured by a capacitance technique. Flow-regime transition was observed with high-speed photography. A 1-hr contact time between Freon-11 and nitrogen at 130 0 F (54.4 0 C) and 60 psig (0.517 MPa) was found to greatly affect the steady-state subcooled-boiling initial conditions. Delay in bubble growth was observed in adiabatic blowdown runs. This was caused by the conditions of thermodynamic nonequilibrium required for the unstable bubble growth. For the diabatic runs, equilibrium was more closely approached in the test section during the early phase of blowdown

  15. Flow Reversal of Fully-Developed Mixed MHD Convection in Vertical Channels

    International Nuclear Information System (INIS)

    Saleh, H.; Hashim, I.

    2010-01-01

    The present analysis is concerned with flow reversal phenomena of the fully-developed laminar combined free and forced MHD convection in a vertical parallel-plate channel. The effect of viscous dissipation is taken into account. Flow reversal adjacent to the cold (or hot) wall is found to exist within the channel as Gr/Re is above (or below) a threshold value. Parameter zones for the occurrence of reversed flow are presented. (fundamental areas of phenomenology(including applications))

  16. Speciation with gene flow in equids despite extensive chromosomal plasticity.

    Science.gov (United States)

    Jónsson, Hákon; Schubert, Mikkel; Seguin-Orlando, Andaine; Ginolhac, Aurélien; Petersen, Lillian; Fumagalli, Matteo; Albrechtsen, Anders; Petersen, Bent; Korneliussen, Thorfinn S; Vilstrup, Julia T; Lear, Teri; Myka, Jennifer Leigh; Lundquist, Judith; Miller, Donald C; Alfarhan, Ahmed H; Alquraishi, Saleh A; Al-Rasheid, Khaled A S; Stagegaard, Julia; Strauss, Günter; Bertelsen, Mads Frost; Sicheritz-Ponten, Thomas; Antczak, Douglas F; Bailey, Ernest; Nielsen, Rasmus; Willerslev, Eske; Orlando, Ludovic

    2014-12-30

    Horses, asses, and zebras belong to a single genus, Equus, which emerged 4.0-4.5 Mya. Although the equine fossil record represents a textbook example of evolution, the succession of events that gave rise to the diversity of species existing today remains unclear. Here we present six genomes from each living species of asses and zebras. This completes the set of genomes available for all extant species in the genus, which was hitherto represented only by the horse and the domestic donkey. In addition, we used a museum specimen to characterize the genome of the quagga zebra, which was driven to extinction in the early 1900s. We scan the genomes for lineage-specific adaptations and identify 48 genes that have evolved under positive selection and are involved in olfaction, immune response, development, locomotion, and behavior. Our extensive genome dataset reveals a highly dynamic demographic history with synchronous expansions and collapses on different continents during the last 400 ky after major climatic events. We show that the earliest speciation occurred with gene flow in Northern America, and that the ancestor of present-day asses and zebras dispersed into the Old World 2.1-3.4 Mya. Strikingly, we also find evidence for gene flow involving three contemporary equine species despite chromosomal numbers varying from 16 pairs to 31 pairs. These findings challenge the claim that the accumulation of chromosomal rearrangements drive complete reproductive isolation, and promote equids as a fundamental model for understanding the interplay between chromosomal structure, gene flow, and, ultimately, speciation.

  17. Edge topology and flows in the reversed-field pinch

    International Nuclear Information System (INIS)

    Spizzo, G.; Agostini, M.; Scarin, P.; Vianello, N.; Cappello, S.; Puiatti, M. E.; Valisa, M.; White, R. B.

    2012-01-01

    Edge topology and plasma flow deeply influence transport in the reversed-field pinch as well as in all fusion devices, playing an important role in many practical aspects of plasma performance, such as access to enhanced confinement regimes, the impact on global power balance and operative limits, such as the density limit (Spizzo G. et al 2010 Plasma Phys. Control. Fusion 52 095011). A central role is played by the edge electric field, which is determined by the ambipolar constraint guaranteeing quasi-neutrality in a sheath next to the plasma wall. Its radial component is experimentally determined in RFX over the whole toroidal angle by means of a diagnostic set measuring edge plasma potential and flow with different techniques (Scarin P. et al 2011 Nucl. Fusion 51 073002). The measured radial electric field is used to construct the potential in the form Φ(ψ p , θ, ζ) (ψ p radial coordinate, θ, ζ angles), by means of the Hamiltonian guiding-centre code ORBIT. Simulations show that a proper functional form of the potential can balance the differential radial diffusion of electrons and ions subject to m = 0 magnetic island O- and X-points. Electrons spend more time in the X-points of such islands than in O-points; ions have comparatively larger drifts and their radial motion is more uniform over the toroidal angle. The final spatial distribution of Φ(ψ p , θ, ζ) results in a complex 3D pattern, with convective cells next to the wall. Generally speaking, an edge topology dominating parallel transport with a given symmetry brings about an edge potential with the same symmetry. This fact helps us to build a first step of a unified picture of the effect of magnetic topology on the Greenwald limit, and, more generally, on flows in the edge of RFPs and tokamaks. (paper)

  18. Analysis of reverse flow in inverted U-tubes of steam generator under natural circulation condition

    International Nuclear Information System (INIS)

    Yang Ruichang; Liu Ruolei; Liu Jinggong; Qin Shiwei

    2008-01-01

    In this paper, we report on the analysis of reverse flow in inverted U-tubes of a steam generator under natural circulation condition. The mechanism of reverse flow in inverted U-tubes of the steam generator with natural circulation is graphically analyzed by using the full-range characteristic curve of parallel U-tubes. The mathematical model and numerical calculation method for analyzing the reverse flow in inverted U-tubes of the steam generator with natural circulation have been developed. The reverse flow in an inverted U-tube steam generator of a simulated pressurized water reactor with natural circulation in analyzed. Through the calculation, the mass flow rates of normal and reverse flows in individual U-tubes are obtained. The predicted sharp drop of the fluid temperature in the inlet plenum of the steam generator due to reverse flow agrees very well with the experimental data. This indicates that the developed mathematical model and solution method can be used to correctly predict the reverse flow in the inverted U-tubes of the steam generator with natural circulation. The obtained results also show that in the analysis of natural circulation flow in the primary circuit, the reverse flow in the inverted U-tubes of the steam generator must be taken into account. (author)

  19. Study on reverse flow characteristics under natural circulation in inverted U-tube steam generator

    International Nuclear Information System (INIS)

    Duan Jun; Zhou Tao; Zhang Lei; Hong Dexun; Liu Ping

    2013-01-01

    Natural circulation is important for application in the nuclear power industry. Aiming at the steam generator of AP1000 pressurized water reactor loop, the mathematical model was established to analysis the reverse flow of single-phase water in the inverted U-tubes of a steam generator in a natural circulation system. The length distribution and the mass flow rates in both tubes with normal and reverse flow were determined respectively. The research results show that the reverse flow may result in sharp decrease of gravity pressure head, circulation mass flow rate and heat release rate of natural circulation. It has adverse influence on natural circulation. (authors)

  20. Gliding arc in tornado using a reverse vortex flow

    International Nuclear Information System (INIS)

    Kalra, Chiranjeev S.; Cho, Young I.; Gutsol, Alexander; Fridman, Alexander; Rufael, Tecle S.

    2005-01-01

    The present article reports a new gliding arc (GA) system using a reverse vortex flow ('tornado') in a cylindrical reactor (gliding arc in tornado, or GAT), as used to preserve the main advantages of traditional GA systems and overcome their main drawbacks. The primary advantages of traditional GA systems retained in the present GAT are the possibility to generate transitional plasma and to avoid considerable electrode erosion. In contrast to a traditional GA, the new GAT system ensures much more uniform gas treatment and has a significantly larger gas residence time in the reactor. The present article also describes the design of the new reactor and its stable operation regime when the variation of GAT current is very small. These features are understood to be very important for most viable applications. Additionally the GAT provides near-perfect thermal insulation from the reactor wall, indicating that the present GAT does not require the reactor wall to be constructed of high-temperature materials. The new GAT system, with its unique properties such as a high level of nonequilibrium and a large residence time, looks very promising for many industrial applications including fuel conversion, carbon dioxide conversion to carbon monoxide and oxygen, surface treatment, waste treatment, flame stabilization, hydrogen sulfide treatment, etc

  1. Reverse flow operation with reactor side feeding : analysis, modeling and simulation

    NARCIS (Netherlands)

    Budhi, Y.W.; Hoebink, J.H.B.J.; Schouten, J.C.

    2004-01-01

    The novel concept of reverse flow operation with reactor side feeding is studied for selective oxidation of NH3 to produce either N2, N2O, or NO. During normal reverse flow operation, where the feeds are alternately introduced from either end of the reactor, the conversion is always lower when

  2. Calculation of reverse flow in inverted U-Tubes of steam generator during natural circulation

    International Nuclear Information System (INIS)

    Yang Ruichang; Liu Jinggong; Liu Ruolei; Qin Shiwei; Huang Yanping

    2010-01-01

    The mechanism of reverse flow in inverted U-tubes of steam generators of pressurized water reactors during natural circulation is analyzed by using the full range characteristic curve of parallel U-tubes. A lumped-distributed model to calculate the reverse flow occurred in inverted U-tubes of real steam generators with a large number of U-tubes during natural circulation is developed. The model has the advantages of quick calculation and high accuracy for the analysis of reverse flow in inverted U-tubes of real steam generators with natural circulation. This model has been used to calculate the normal and reverse flows occurred in inverted U-tubes of a steam generator with natural circulation. The comparison of calculated results indicates a well agreement with that predicted by the model in which normal or reverse flow in each individual U-tube is analyzed, which verifies the reliability of the model developed in this paper. (authors)

  3. FLUX ENHANCEMENT IN CROSSFLOW MEMBRANE FILTRATION: FOULING AND IT'S MINIMIZATION BY FLOW REVERSAL

    International Nuclear Information System (INIS)

    Shamsuddin Ilias

    2005-01-01

    Fouling problems are perhaps the single most important reason for relatively slow acceptance of ultrafiltration in many areas of chemical and biological processing. To overcome the losses in permeate flux associated with concentration polarization and fouling in cross flow membrane filtration, we investigated the concept of flow reversal as a method to enhance membrane flux in ultrafiltration. Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentration boundary layers at or near the membrane surface. Further more, periodic reversal of the flow direction of the feed stream at the membrane surface results in prevention and mitigation of membrane fouling. Consequently, these advantages are expected to enhance membrane flux significantly. A crossflow membrane filtration unit was designed and built to test the concept of periodic flow reversal for flux enhancement. The essential elements of the system include a crossflow hollow fiber membrane module integrated with a two-way valve to direct the feed flow directions. The two-way valve is controlled by a controller-timer for periodic reversal of flow of feed stream. Another important feature of the system is that with changing feed flow direction, the permeate flow direction is also changed to maintain countercurrent feed and permeate flows for enhanced mass transfer driving force (concentration difference). In this report, we report our application of Flow Reversal technique in clarification of apple juice containing pectin. The presence of pectin in apple juice makes the clarification process difficult and is believed to cause membrane fouling. Of all compounds found in apple juice, pectin is most often identified as the major hindrance to filtration performance. Based on our ultrafiltration experiments with apple juice, we conclude that under flow reversal conditions, the permeate flux is significantly enhanced when compared with the conventional unidirectional flow. Thus, flow reversal

  4. Reversing flow causes passive shark scale actuation in a separating turbulent boundary layer

    Science.gov (United States)

    Lang, Amy; Gemmell, Bradford; Motta, Phil; Habegger, Laura; Du Clos, Kevin; Devey, Sean; Stanley, Caleb; Santos, Leo

    2017-11-01

    Control of flow separation by shortfin mako skin in experiments has been demonstrated, but the mechanism is still poorly understood yet must be to some extent Re independent. The hypothesized mechanisms inherent in the shark skin for controlling flow separation are: (1) the scales, which are capable of being bristled only by reversing flow, inhibit flow reversal events from further development into larger-scale separation and (2) the cavities formed when scales bristle induces mixing of high momentum flow towards the wall thus energizing the flow close to the surface. Two studies were carried out to measure passive scale actuation caused by reversing flow. A small flow channel induced an unsteady, wake flow over the scales prompting reversing flow events and scale actuation. To resolve the flow and scale movements simultaneously we used specialized optics at high magnification (1 mm field of view) at 50,000 fps. In another study, 3D printed models of shark scales, or microflaps (bristling capability up to 50 degrees), were set into a flat plate. Using a tripped, turbulent boundary layer grown over the long flat plate and a localized adverse pressure gradient, a separation bubble was generated within which the microflaps were placed. Passive flow actuation of both shark scales and microflaps by reversing flow was observed. Funding from Army Research Office and NSF REU site Grant.

  5. Chemical-looping combustion in a reverse-flow fixed bed reactor

    International Nuclear Information System (INIS)

    Han, Lu; Bollas, George M.

    2016-01-01

    A reverse-flow fixed bed reactor concept for CLC (chemical-looping combustion) is explored. The limitations of conventional fixed bed reactors, as applied to CLC, are overcome by reversing the gas flow direction periodically to enhance the mixing characteristics of the bed, thus improving oxygen carrier utilization and energy efficiency with respect to power generation. The reverse-flow reactor is simulated by a dusty-gas model and compared with an equivalent fixed bed reactor without flow reversal. Dynamic optimization is used to calculate conditions at which each reactor operates at maximum energy efficiency. Several cases studies illustrate the benefits of reverse-flow operation for the CLC with CuO and NiO oxygen carriers and methane and syngas fuels. The results show that periodic reversal of the flow during reduction improves the contact between the fuel and unconverted oxygen carrier, enabling the system to suppress unwanted catalytic reactions and axial temperature and conversion gradients. The operational scheme presented reduces the fluctuations of temperature during oxidation and increases the high-temperature heat produced by the process. CLC in a reverse-flow reactor has the potential to achieve higher energy efficiency than conventional fixed bed CLC reactors, when integrated with a downstream gas turbine of a combined cycle power plant. - Highlights: • Reverse-flow fixed bed CLC reactors for combined cycle power systems. • Dynamic optimization tunes operation of batch and transient CLC systems. • The reverse-flow CLC system provides stable turbine-ready gas stream. • Reverse-flow CLC fixed bed reactor has superior CO 2 capture and thermal efficiency.

  6. Nocturnal reverse flow in water-in-glass evacuated tube solar water heaters

    International Nuclear Information System (INIS)

    Tang, Runsheng; Yang, Yuqin

    2014-01-01

    Highlights: • Performance of water-in-glass evacuated tube solar water heaters (SWH) at night was studied. • Experimental measurements showed that reverse flow occurred in SWHs at night. • Reverse flow in SWHs was very high but the heat loss due to reverse flow was very low. • Reverse flow seemed not sensitive to atmospheric clearness but sensitive to collector tilt-angle. - Abstract: In this work, the thermal performance of water-in-glass evacuated tube solar water heaters (SWH) at nights was experimentally investigated. Measurements at nights showed that the water temperature in solar tubes was always lower than that in the water tank but higher than the ambient air temperature and T exp , the temperature of water inside tubes predicted in the case of the water in tubes being naturally cooled without reverse flow. This signified that the reverse flow in the system occurred at nights, making the water in solar tubes higher than T exp . It is found that the reverse flow rate in the SWH, estimated based on temperature measurements of water in solar tubes, seemed not sensitive to the atmospheric clearness but sensitive to the collector tilt-angle, the larger the tilt-angle of the collector, the higher the reverse flow rate. Experimental results also showed that, the reverse flow in the SWH was much higher as compared to that in a thermosyphonic domestic solar water heater with flat-plate collectors, but the heat loss from collectors to the air due to reverse flow in SWHs was very small and only took about 8–10% of total heat loss of systems

  7. Reverse stream flow routing by using Muskingum models

    Indian Academy of Sciences (India)

    Reverse stream flow routing is a procedure that determines the upstream hydrograph given the downstream hydrograph. This paper presents the development of methodology for Muskingum models parameter estimation for reverse stream flow routing. The standard application of the Muskingum models involves calibration ...

  8. Experimental study of a reverse flow catalytic converter for a duel fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.; Checkel, M. D. [Alberta Univ., Dept. of Mechanical Engineering, Edmonton, ANB (Canada); Hayes, R. E. [Alberta Univ., Dept, of Chemical and Materials Engineering, Edmonton, AB, (Canada)

    2001-08-01

    Performance of a reverse flow catalytic converter for a methane/diesel dual fuel engine is evaluated under steady and transient engine conditions. The converter is of the monolith honeycomb type with palladium catalyst washcoat. Results of the reverse flow converter's performance was found to be superior for several steady state engine operations when compared to unidirectional flow operation. In transient operations following a step change in engine operating conditions, reverse flow was found to be better than unidirectional flow when the change in engine operation was such as to reduce the exhaust gas temperature. When exhaust gas temperature was increased, reverse flow decreased the rate of increase in the reactor temperature. Testing was done using the transient Japanese 6-Mode tests. Best results were achieved with a switch time in the five seconds to fifteen seconds range. 31 refs., 9 tabs., 24 figs.

  9. Flux Enhancement in Crossflow Membrane Filtration: Fouling and It's Minimization by Flow Reversal. Final Report

    International Nuclear Information System (INIS)

    Shamsuddin Ilias

    2005-01-01

    Fouling problems are perhaps the single most important reason for relatively slow acceptance of ultrafiltration in many areas of chemical and biological processing. To overcome the losses in permeate flux associated with concentration polarization and fouling in cross flow membrane filtration, we investigated the concept of flow reversal as a method to enhance membrane flux in ultrafiltration. Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentration boundary layers at or near the membrane surface. Further more, periodic reversal of the flow direction of the feed stream at the membrane surface results in prevention and mitigation of membrane fouling. Consequently, these advantages are expected to enhance membrane flux significantly. A crossflow membrane filtration unit was designed and built to test the concept of periodic flow reversal for flux enhancement. The essential elements of the system include a crossflow hollow fiber membrane module integrated with a two-way valve to direct the feed flow directions. The two-way valve is controlled by a controller-timer for periodic reversal of flow of feed stream. Another important feature of the system is that with changing feed flow direction, the permeate flow direction is also changed to maintain countercurrent feed and permeate flows for enhanced mass transfer driving force (concentration difference). Three feed solutions (Bovine serum albumin (BSA), apple juice and citrus fruit pectin) were studied in crossflow membrane filtration. These solutes are well-known in membrane filtration for their fouling and concentration polarization potentials. Laboratory-scale tests on a hollow-fiber ultrafiltration membrane module using each of the feed solutes show that under flow reversal conditions, the permeate flux is significantly enhanced when compared with the conventional unidirectional flow. The flux enhancement is dramatic (by an order of magnitude) with increased feed concentration and

  10. Intestinal myoelectric activity and contractile motility in dogs with a reversed jejunal segment after extensive small bowel resection.

    Science.gov (United States)

    Uchiyama, M; Iwafuchi, M; Ohsawa, Y; Yagi, M; Iinuma, Y; Ohtani, S

    1992-06-01

    To evaluate the functioning and effectiveness of a reversed jejunal segment after extensive small bowel resection, we continuously measured the postoperative bowel motility (using bipolar electrodes and/or contractile strain gage force transducers) in interdigestive and postprandial conscious dogs at 2 to 5 weeks after surgery. The fasting duodenal migrating myoelectric (or motor) complex (MMC) occurred at markedly longer intervals in dogs with a 20-cm reversed jejunal segment created after 75% to 80% extensive small bowel resection (group 3) than in dogs that received extensive resection alone (group 2) or dogs that underwent construction of a reversed jejunal segment without bowel resection (group 1). The MMC arising from the duodenum was often interrupted at the jejunum above the proximal anastomosis and did not migrate smoothly to the reversed segment or terminal ileum in group 3. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum above the proximal anastomosis in group 3. The duration of the postprandial period without duodenal MMC activity was significantly prolonged in groups 2 and 3. These results suggest that the transit time and passage of intestinal contents were delayed and that the periodical MMC was disturbed in group 3. The delay of transit time was due to prolongation of the interval between duodenal MMCs, the interruption of MMC propagation at the jejunum above the proximal anastomosis, the dominance of MMCs that followed the inherent anatomical continuity of the bowel, and discordant movements across the proximal anastomosis. Functional obstruction could be a potential problem in a 20-cm reversed jejunal segment inserted after extensive small bowel resection.

  11. Resulting long-term intestinal motility in dogs following construction of a reversed jejunal segment after extensive small bowel resection.

    Science.gov (United States)

    Uchiyama, M; Iwafuchi, M; Ohsawa, Y; Yagi, M; Iinuma, Y; Ohtani, S

    1994-10-01

    To evaluate the long-term function and effective motility of a reversed jejunal segment after extensive small bowel resection, the authors continuously measured postoperative bowel motility during interdigestive and postprandial periods in conscious dogs 6 to 10 months after surgery. The long-term findings were compared with previously reported short-term results measured 2 to 4 weeks after the operation. In the long-term follow-up dogs with a 20-cm reversed jejunal segment constructed after extensive (75% to 80%) small bowel resection, the fasting duodenal migrating myoelectric (or motor) complex (MMC) was often interrupted in the jejunum above the reversed segment, and did not migrate smoothly to the reversed segment or terminal ileum. The MMCs arising from the duodenum predominantly propagated to the ileum through the inherent anatomic continuity of the bowel. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum, above the proximal anastomosis. These findings are similar to those of the MMC propagation pattern noted 2 to 4 weeks after surgery. However, the postprandial duration without duodenal MMC activity was significantly shorter in the dogs with long-term follow-up than in those with short-term follow-up (both were longer than in control dogs). Marked dilatation of the jejunum and reversed jejunal segment was noted across the proximal anastomosis. These results suggest that the transit time and passage of intestinal contents can be delayed and stagnated for at least 10 months after extensive small bowel resection with a 20-cm reversed jejunal segment.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system.

    Science.gov (United States)

    Altmeyer, Sebastian; Do, Younghae; Lai, Ying-Cheng

    2015-12-21

    We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant azimuthal modes. Without external magnetic field flows are stable and pro-grade with respect to the rotation of the inner cylinder. More complex behaviors can arise when an axial or a transverse magnetic field is applied. Depending on the direction and strength of the field, multi-stable wavy states and bifurcations can occur. We uncover the phenomenon of flow pattern reversal as the strength of the magnetic field is increased through a critical value. In between the regimes of pro-grade and retrograde flow rotations, standing waves with zero angular velocities can emerge. A striking finding is that, under a transverse magnetic field, a second reversal in the flow pattern direction can occur, where the flow pattern evolves into pro-grade rotation again from a retrograde state. Flow reversal is relevant to intriguing phenomena in nature such as geomagnetic reversal. Our results suggest that, in ferrofluids, flow pattern reversal can be induced by varying a magnetic field in a controlled manner, which can be realized in laboratory experiments with potential applications in the development of modern fluid devices.

  13. Nocturnal Reversed Flows Above Parallel Ridges in Perdigão, Portugal

    Science.gov (United States)

    Krishnamurthy, R.; Fernando, H. J.; Leo, L. S.; Vassallo, D.; Hocut, C. M.; Creegan, E.; Rodriguez, C. V.; Palma, J. L.

    2017-12-01

    Prediction of topographically forced or induced wind events is extremely important for dispersion modeling and wind energy studies in complex terrain. To improve the current understanding of micro-scale processes over complex terrain, a large-scale field experiment was conducted in Perdigão, Portugal from May 1st, 2017 to June 15th, 2017. Measurements over a periodic valley were performed using 52 meteorological met-masts, 30 Doppler Lidars (scanning & vertical profilers), 2 tethered lifting systems and other remote sensing instruments (Sodar-rass, wind profilers & radiometer), and radiosondes were released every 6 hours over the period of study. The observations showed several cases of flow reversals confined to a thin layer of 70 - 100 m above the ridge under stably stratified conditions. These flow reversals were mostly observed during the lee wave formation over the periodic valley. It was observed that the flow reversal occurs predominantly under two atmospheric conditions: a) presence of large recirculation zones on the lee side of the hill causing a pressure gradient between the lee-side floor and the mountain ridge, and b) local change in the horizontal pressure gradient due to differential heating rates of the neighboring valley atmospheres. Microscale flow simulations could capture these observed flow reversals. Based on the network of tower instruments and remote sensing devices, the development, structure and occurrences of the flow reversals are being analyzed and quantified. Since these flow reversals are observed within the rotor swept area of modern wind turbines, they would drastically increase the fatigue loads on wind turbine blades. This presentation will include reversed flow observations from several synchronized scanning Doppler Lidars and meteorological towers and a theoretical framework for reverse flow over parallel valleys.

  14. Flow and breakup in extension of low-density polyethylene

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Fasano, Andrea

    2018-01-01

    The breakup during the extension of a low-density polyethylene Lupolen 1840D, as observed experimentally by Burghelea et al. (J Non-Newt Fluid Mech 166:1198–1209 2011), was investigated. This was observed during the extension of an circular cylinder with radius R0 = 4 mm and length L0 = 5mm....... The sample was attached to two flat end plates, separated exponentially in time to extend the samples. A numerical method based on a Lagrangian kinematics description in a continuum mechanical framework was used to calculate the extension of an initially cylindrically shaped sample with and without small...... the error bars as reported experimentally by Burghelea et al. (J Non-Newt Fluid Mech 166:1198–1209 2011). At low extensional rates, the measurements were considerably above the calculated ones. A very small relative suppression in the surface (0.1%) was required to achieve an agreement with all measurements...

  15. Safety analysis of switching between reductive and oxidative conditions in a reaction coupling reverse flow reactor.

    NARCIS (Netherlands)

    van Sint Annaland, M.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    2001-01-01

    A new reverse flow reactor is developed where endothermic reactants (propane dehydrogenation) and exothermic reactants (fuel combustion) are fed sequentially to a monolithic catalyst, while periodically alternating the inlet and outlet positions. Upon switching from reductive to oxidative conditions

  16. Computer modeling of the stalled flow of a rotating cylinder and the reverse magnus effect

    Science.gov (United States)

    Belotserkovskii, S. M.; Kotovskii, V. N.; Nisht, M. I.; Fedorov, R. M.

    1985-02-01

    Unsteady stalled flow around a rotating cylinder is investigated in a numerical experiment. Attention is mostly given to the reverse Magnus effect which was discovered in tube experiments at some critical rotational speed of the cylinder.

  17. Reversing tidal flow and estuarine morphodynamics in the Metronome laboratory flume

    NARCIS (Netherlands)

    Kleinhans, M.G.; Leuven, J.R.F.W.; Braat, L.; van der Vegt, M.; van Maarseveen, M.C.G.; Markies, H.; Roosendaal, C.; van Eijk, A.M.

    2016-01-01

    Our objective is to test a novel experimental principle for creating reversing tidal flows of sufficient strength to cause estuarine morphodynamics. The study of estuarine morphodynamics has hitherto been limited to field observation and numerical modelling, whilst fluvial morphodynamics have

  18. Speciation with gene flow in equids despite extensive chromosomal plasticity

    DEFF Research Database (Denmark)

    Jáónsson, Hákon; Schubert, Mikkel; Seguin-Orlando, Andaine

    2014-01-01

    Significance Thirty years after the first DNA fragment from the extinct quagga zebra was sequenced, we set another milestone in equine genomics by sequencing its entire genome, along with the genomes of the surviving equine species. This extensive dataset allows us to decipher the genetic makeup ...

  19. Reversal of flow in the inferior vena cava and hepatic veins on dynamic CT

    International Nuclear Information System (INIS)

    Lelij, H. van der; Mallens, W.M.C.

    1988-01-01

    A tricuspid insufficiency may not be clinically evident and may remain unknown to the clinician. The phenomenon of a reversal of inferior vena caval blood flow and hepatic veins is known to occur in tricuspid regurgitation from right ventricular angiography and duplex scanning. Demonstration of such a reversal flow on a dynamic CT scan, as in our case, has, to our knowledge, not as yet been reported

  20. Cluster observation of plasma flow reversal in the magnetotail during a substorm

    Directory of Open Access Journals (Sweden)

    A. T. Y. Lui

    2006-08-01

    Full Text Available We investigate in detail a reversal of plasma flow from tailward to earthward detected by Cluster at the downstream distance of ~19 RE in the midnight sector of the magnetotail on 22 August 2001. This flow reversal was accompanied by a sign reversal of the Bz component and occurred during the late substorm expansion phase as revealed by simultaneous global view of auroral activity from IMAGE. We examine the associated Hall current system signature, current density, electric field, Lorentz force, and current dissipation/dynamo term, the last two parameters being new features that have not been studied previously for plasma flow reversals. It is found that (1 there was no clear quadrupole Hall current system signature organized by the flow reversal time, (2 the x-component of the Lorentz force did not change sign while the other two did, (3 the timing sequence of flow reversal from the Cluster configuration did not match tailward motion of a single plasma flow source, (4 the electric field was occasionally dawnward, producing a dynamo effect, and (5 the electric field was occasionally larger at the high-latitude plasma sheet than near the neutral sheet. These observations are consistent with the current disruption model for substorms in which these disturbances are due to shifting dominance of multiple current disruption sites and turbulence at the observing location.

  1. Cluster observation of plasma flow reversal in the magnetotail during a substorm

    Directory of Open Access Journals (Sweden)

    A. T. Y. Lui

    2006-08-01

    Full Text Available We investigate in detail a reversal of plasma flow from tailward to earthward detected by Cluster at the downstream distance of ~19 RE in the midnight sector of the magnetotail on 22 August 2001. This flow reversal was accompanied by a sign reversal of the Bz component and occurred during the late substorm expansion phase as revealed by simultaneous global view of auroral activity from IMAGE. We examine the associated Hall current system signature, current density, electric field, Lorentz force, and current dissipation/dynamo term, the last two parameters being new features that have not been studied previously for plasma flow reversals. It is found that (1 there was no clear quadrupole Hall current system signature organized by the flow reversal time, (2 the x-component of the Lorentz force did not change sign while the other two did, (3 the timing sequence of flow reversal from the Cluster configuration did not match tailward motion of a single plasma flow source, (4 the electric field was occasionally dawnward, producing a dynamo effect, and (5 the electric field was occasionally larger at the high-latitude plasma sheet than near the neutral sheet. These observations are consistent with the current disruption model for substorms in which these disturbances are due to shifting dominance of multiple current disruption sites and turbulence at the observing location.

  2. Performance characteristics of plane-wall venturi-like reverse flow diverters

    International Nuclear Information System (INIS)

    Smith, G.V.; Counce, R.M.

    1982-01-01

    The results of an analytical and experimental study of plane-wall venturi-like reverse flow diverters (RFD) are presented. In general, the flow characteristics of the RFD are reasonably well predicted by the mathematical model of the RFD, although a divergence between theory and data is observed for the output characteristics in the reverse flow mode as the output impedance is reduced. Overall, the performance of these devices indicates their usefulness in fluid control and fluid power systems, such as displacement pumping systems

  3. Characterization of Rare Reverse Flow Events in Adverse Pressure Gradient Turbulent Boundary Layers

    Science.gov (United States)

    Kaehler, Christian J.; Bross, Matthew; Fuchs, Thomas

    2017-11-01

    Time-resolved tomographic flow fields measured in the viscous sublayer region of a turbulent boundary layer subjected to an adverse pressure gradient (APG) are examined with the aim to resolve and characterize reverse flow events at Reτ = 5000. The fields were measured using a novel high resolution tomographic particle tracking technique. It is shown that this technique is able to fully resolve mean and time dependent features of the complex three-dimensional flow with high accuracy down to very near-wall distances ( 10 μm). From time resolved Lagrangian particle trajectories, statistical information as well as instantaneous topological features of near-wall flow events are deduced. Similar to the zero pressure gradient case (ZPG), it was found that individual events with reverse flow components still occur relatively rarely under the action of the pressure gradient investigated here. However, reverse flow events comprised of many individual events, are shown to appear in relatively organized groupings in both spanwise and streamise directions. Furthermore, instantaneous measurements of reverse flow events show that these events are associated with the motion of low-momentum streaks in the near-wall region. This work is supported by the Priority Programme SPP 1881 Turbulent Superstructures and the individual project Grant KA1808/8-2 of the Deutsche Forschungsgemeinschaft.

  4. Convective flow reversal in self-powered enzyme micropumps.

    Science.gov (United States)

    Ortiz-Rivera, Isamar; Shum, Henry; Agrawal, Arjun; Sen, Ayusman; Balazs, Anna C

    2016-03-08

    Surface-bound enzymes can act as pumps that drive large-scale fluid flows in the presence of their substrates or promoters. Thus, enzymatic catalysis can be harnessed for “on demand” pumping in nano- and microfluidic devices powered by an intrinsic energy source. The mechanisms controlling the pumping have not, however, been completely elucidated. Herein, we combine theory and experiments to demonstrate a previously unreported spatiotemporal variation in pumping behavior in urease-based pumps and uncover the mechanisms behind these dynamics. We developed a theoretical model for the transduction of chemical energy into mechanical fluid flow in these systems, capturing buoyancy effects due to the solution containing nonuniform concentrations of substrate and product. We find that the qualitative features of the flow depend on the ratios of diffusivities δ=D(P)/D(S) and expansion coefficients β=β(P)/β(S) of the reaction substrate (S) and product (P). If δ>1 and δ>β (or if δself-powered fluidic devices.

  5. Extensive gene flow over Europe and possible speciation

    Energy Technology Data Exchange (ETDEWEB)

    VINCENOT, Dr. LUCIE [Centre d’Ecologie Fonctionnelle et Evolutive Montpellier, France; NARA, Dr. KAZUHIDE [Department of Natural Environmental Studies, The University of Tokyo, Japan; STHULTZ, CHRISTOPHER [Centre d’Ecologie Fonctionnelle et Evolutive Montpellier, France; Labbe, Jessy L [ORNL; DUBOIS, MARIE-PIERRE [Centre d’Ecologie Fonctionnelle et Evolutive Montpellier, France; TEDERSOO, LEHO [University of Tartu, Estonia; Martin, Francis [INRA, Nancy, France; SELOSSE, Dr. MARC-ANDRE [Centre d’Ecologie Fonctionnelle et Evolutive Montpellier, France

    2012-01-01

    Biogeographical patterns and large-scale genetic structure have been little studied in ectomycorrhizal (EM) fungi, despite the ecological and economic importance of EM symbioses. We coupled population genetics and phylogenetic approaches to understand spatial structure in fungal populations on a continental scale. Using nine microsatellite markers, we characterized gene flow among 16 populations of the widespread EM basidiomycete Laccaria amethystina over Europe (i.e. over 2900 km). We also widened our scope to two additional populations from Japan (104 km away) and compared them with European populations through microsatellite markers and multilocus phylogenies, using three nuclear genes (NAR, G6PD and ribosomal DNA) and two mitochondrial ribosomal genes. European L. amethystina populations displayed limited differentiation (average FST = 0.041) and very weak isolation by distance (IBD). This panmictic European pattern may result from effective aerial dispersal of spores, high genetic diversity in populations and mutualistic interactions with multiple hosts that all facilitate migration. The multilocus phylogeny based on nuclear genes confirmed that Japanese and European specimens were closely related but clustered on a geographical basis. By using microsatellite markers, we found that Japanese populations were strongly differentiated from the European populations (FST = 0.416), more than expected by extrapolating the European pattern of IBD. Population structure analyses clearly separated the populations into two clusters, i.e. European and Japanese clusters. We discuss the possibility of IBD in a continuous population (considering some evidence for a ring species over the Northern Hemisphere) vs. an allopatric speciation over Eurasia, making L. amethystina a promising model of intercontinental species for future studies.

  6. Local wettability reversal during steady-state two-phase flow in porous media.

    Science.gov (United States)

    Sinha, Santanu; Grøva, Morten; Ødegården, Torgeir Bryge; Skjetne, Erik; Hansen, Alex

    2011-09-01

    We study the effect of local wettability reversal on remobilizing immobile fluid clusters in steady-state two-phase flow in porous media. We consider a two-dimensional network model for a porous medium and introduce a wettability alteration mechanism. A qualitative change in the steady-state flow patterns, destabilizing the percolating and trapped clusters, is observed as the system wettability is varied. When capillary forces are strong, a finite wettability alteration is necessary to move the system from a single-phase to a two-phase flow regime. When both phases are mobile, we find a linear relationship between fractional flow and wettability alteration.

  7. Impact of drag reducing polymers on the onset of instability in a pipe with reverse flow

    Science.gov (United States)

    Shashank, H. J.; Sreenivas, K. R.

    2014-11-01

    The objective of this study is to understand the mechanism by which drag reducing polymer (DRP) additives modify turbulent flow, so as to reduce turbulent drag. Reverse flow in a pipe occurs when the fluid close to the wall moves in an opposite direction to that of the core fluid. Reverse flow is established by using a piston-cylinder mechanism, the programmed motion of which imparts a known impulse to the fluid. When the piston is stopped at the end of the stroke, fluid inertia makes the core of the flow to continue in the same direction. In order to conserve mass, reverse flow is established close to the wall. An inflection point is thus formed, leading to flow instability above a critical Reynolds number. Dye and streak flow visualization experiments are performed to highlight the impact of DRP additives (polyethylene oxide, PEO, dissolved in water). The time of onset of the instability and the wavelength of the observed instability are studied in systems with and without DRP additives. This study will provide further insight into the phenomenon of turbulent polymer drag reduction.

  8. Structural and temporal requirements for geomagnetic field reversal deduced from lava flows.

    Science.gov (United States)

    Singer, Brad S; Hoffman, Kenneth A; Coe, Robert S; Brown, Laurie L; Jicha, Brian R; Pringle, Malcolm S; Chauvin, Annick

    2005-03-31

    Reversals of the Earth's magnetic field reflect changes in the geodynamo--flow within the outer core--that generates the field. Constraining core processes or mantle properties that induce or modulate reversals requires knowing the timing and morphology of field changes that precede and accompany these reversals. But the short duration of transitional field states and fragmentary nature of even the best palaeomagnetic records make it difficult to provide a timeline for the reversal process. 40Ar/39Ar dating of lavas on Tahiti, long thought to record the primary part of the most recent 'Matuyama-Brunhes' reversal, gives an age of 795 +/- 7 kyr, indistinguishable from that of lavas in Chile and La Palma that record a transition in the Earth's magnetic field, but older than the accepted age for the reversal. Only the 'transitional' lavas on Maui and one from La Palma (dated at 776 +/- 2 kyr), agree with the astronomical age for the reversal. Here we propose that the older lavas record the onset of a geodynamo process, which only on occasion would result in polarity change. This initial instability, associated with the first of two decreases in field intensity, began approximately 18 kyr before the actual polarity switch. These data support the claim that complete reversals require a significant period for magnetic flux to escape from the solid inner core and sufficiently weaken its stabilizing effect.

  9. New Clasp Assembly for Distal Extension Removable Partial Dentures: The Reverse RPA Clasp.

    Science.gov (United States)

    Hakkoum, Mohammad Ayham

    2016-07-01

    Several clasp types are used in distal extension removable partial dentures. In some cases the terminal abutments have only distal retentive undercuts that can be occupied by bar clasps; however, bar clasps may be contraindicated with no suitable alternative. This article presents a reasonable solution by introducing a new clasp design as a modification to the well-known RPA clasp. The design includes a mesial rest, proximal plate, and buccal retentive arm arising from the rest and extending to reach the distal retentive undercut. © 2015 by the American College of Prosthodontists.

  10. A reverse flow catalytic membrane reactor for the production of syngas: an experimental study

    NARCIS (Netherlands)

    Smit, J.; Bekink, G.J.; van Sint Annaland, M.; Kuipers, J.A.M.

    2005-01-01

    In this paper experimental results are presented for a demonstration unit of a recently proposed novel integrated reactor concept (Smit et. al., 2005) for the partial oxidation of natural gas to syngas (POM), namely a Reverse Flow Catalytic Membrane Reactor (RFCMR). Natural gas has great potential

  11. Air purification by catalytic oxidation in a reactor with periodic flow reversal

    NARCIS (Netherlands)

    van de Beld, L.; van de Beld, Bert; Westerterp, K.R.

    1994-01-01

    The behaviour of an adiabatic packed bed reactor with periodic flow reversal has been studied by means of model calculations. A heterogeneous model as well as a pseudo-homogeneous model have been developed. It is shown that a high degree of conversion can be obtained in an autothermal process even

  12. Reverse radiometric flow injection analysis (RFIA) of radioactive waste-waters with an ASIA (Ismatec) analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-07-01

    A new application of reverse radiometric flow injection analysis is described. RFIA was used for the analysis of radioactive wastewaters. ASIA (Ismatec) analyzer with NaI(Tl) scintillation detector was used in the study of analysis of [sup 131]I containing waste-aster. (author) 4 refs.; 3 figs.

  13. RELAP5 analyses of two hypothetical flow reversal events for the Advanced Neutron Source Reactor

    International Nuclear Information System (INIS)

    Chen, N.C.J.; Wendel, M.W.; Yoder, G.L. Jr.

    1995-01-01

    The reactor design features 4 independent cooling loops (3 active, 1 standby), each containing a main circulation pump (with battery powered pony motor), heat exchanger, an accumulator, and a check valve. The first transient assumes one of these pumps fails, and also that the check valve in that loop remains stuck open. This accident is considered extremely unlikely. Flow reverses in this loop, reducing core flow because much of the coolant is diverted from the intact loops back through the failed loop. The second transient examines a 102-mm-dia instantaneous pipe break near the core inlet (worst break location). A break is assumed to occur 90 s after a total loss-of-offsite power. Core flow reversal occurs because accumulator injection overpowers the diminishing pump flow. Safety margins are evaluated against 4 thermal limits: T wall = T sat , incipient boiling, onset of significant void, and critical heat flux. For the first transient, results show that these limits are not exceeded (at 95% non-exceedance probability level) if the pony motor battery lasts 30 minutes (present design value). For the second transient, the closest approach of the fuel surface temperature to local saturation temperature during core flow reversal is about 39 C, so the fuel remains cool during this transient. Although this work is for the ANSR geometry and operating conditions, the general conclusion may be applicable to other highly subcooled reactor systems

  14. Issues in measure-preserving three dimensional flow integrators: Self-adjointness, reversibility, and non-uniform time stepping

    International Nuclear Information System (INIS)

    Finn, John M.

    2015-01-01

    Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a “special divergence-free” (SDF) property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Feng and Shang [Numer. Math. 71, 451 (1995)], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Richardson and Finn [Plasma Phys. Controlled Fusion 54, 014004 (2012

  15. Asymmetry reversal of ion collection by mach probes in flowing unmagnetized plasmas

    International Nuclear Information System (INIS)

    Ko, E; Hershkowitz, N

    2006-01-01

    Measurements of ion current in flowing unmagnetized plasmas were performed with planar and spherical Mach probes in two different devices, one a dc multi-dipole plasma device for subsonic flow within a presheath region and the other a double plasma device for supersonic flow. Asymmetry reversal, which is higher ion current to the downstream side of the probe compared with the upstream side current, was observed for high probe bias compared with the electron temperature, relatively low ion drift velocity and Debye length comparable to probe radius. These data are in qualitative agreement with a recent numerical calculation by Hutchinson. As suggested by Hutchinson, it was found that the current ratio depended on the plasma parameters, especially for finite Debye length and high probe bias. Asymmetry reversal emphasizes the lack of validity of using the current ratio except for narrow parameter ranges. This study is the first experiment to demonstrate the non-intuitive phenomenon predicted by Hutchinson's numerical calculation

  16. Reverse flow and vortex breakdown in a shear-thinning fluid

    International Nuclear Information System (INIS)

    Cabeza, C; Sarasua, G; Barrere, N; Marti, A C

    2011-01-01

    The effect of polymer concentration on the development of reverse secondary flow and vortex breakdown was studied using a viscoelastic solution of polyacrlylamide in water. The fluid was contained in cylindrical containers of two different radii, the top end wall of which rotated at a varying speed, thus, imparting a circulating motion to the fluid. Whereas using a newtonian fluid, streamlines will occupy the entire container, the flow of a shear-thinning fluid may divide into two cells of opposite circulating motion. The curve of critical Reynolds and elasticity numbers (Re, E) values corresponding to the development of reverse flow was obtained over a wide range of Re values. Vortex breakdown was found to occur at extremely low Re values.

  17. Toroidal equilibrium states with reversed magnetic shear and parallel flow in connection with the formation of Internal Transport Barriers

    Science.gov (United States)

    Kuiroukidis, Ap.; Throumoulopoulos, G. N.

    2015-08-01

    We construct nonlinear toroidal equilibria of fixed diverted boundary shaping with reversed magnetic shear and flows parallel to the magnetic field. The equilibria have hole-like current density and the reversed magnetic shear increases as the equilibrium nonlinearity becomes stronger. Also, application of a sufficient condition for linear stability implies that the stability is improved as the equilibrium nonlinearity correlated to the reversed magnetic shear gets stronger with a weaker stabilizing contribution from the flow. These results indicate synergetic stabilizing effects of reversed magnetic shear, equilibrium nonlinearity and flow in the establishment of Internal Transport Barriers (ITBs).

  18. Predicting Flow Reversals in a Computational Fluid Dynamics Simulated Thermosyphon Using Data Assimilation.

    Science.gov (United States)

    Reagan, Andrew J; Dubief, Yves; Dodds, Peter Sheridan; Danforth, Christopher M

    2016-01-01

    A thermal convection loop is a annular chamber filled with water, heated on the bottom half and cooled on the top half. With sufficiently large forcing of heat, the direction of fluid flow in the loop oscillates chaotically, dynamics analogous to the Earth's weather. As is the case for state-of-the-art weather models, we only observe the statistics over a small region of state space, making prediction difficult. To overcome this challenge, data assimilation (DA) methods, and specifically ensemble methods, use the computational model itself to estimate the uncertainty of the model to optimally combine these observations into an initial condition for predicting the future state. Here, we build and verify four distinct DA methods, and then, we perform a twin model experiment with the computational fluid dynamics simulation of the loop using the Ensemble Transform Kalman Filter (ETKF) to assimilate observations and predict flow reversals. We show that using adaptively shaped localized covariance outperforms static localized covariance with the ETKF, and allows for the use of less observations in predicting flow reversals. We also show that a Dynamic Mode Decomposition (DMD) of the temperature and velocity fields recovers the low dimensional system underlying reversals, finding specific modes which together are predictive of reversal direction.

  19. Predicting Flow Reversals in a Computational Fluid Dynamics Simulated Thermosyphon Using Data Assimilation.

    Directory of Open Access Journals (Sweden)

    Andrew J Reagan

    Full Text Available A thermal convection loop is a annular chamber filled with water, heated on the bottom half and cooled on the top half. With sufficiently large forcing of heat, the direction of fluid flow in the loop oscillates chaotically, dynamics analogous to the Earth's weather. As is the case for state-of-the-art weather models, we only observe the statistics over a small region of state space, making prediction difficult. To overcome this challenge, data assimilation (DA methods, and specifically ensemble methods, use the computational model itself to estimate the uncertainty of the model to optimally combine these observations into an initial condition for predicting the future state. Here, we build and verify four distinct DA methods, and then, we perform a twin model experiment with the computational fluid dynamics simulation of the loop using the Ensemble Transform Kalman Filter (ETKF to assimilate observations and predict flow reversals. We show that using adaptively shaped localized covariance outperforms static localized covariance with the ETKF, and allows for the use of less observations in predicting flow reversals. We also show that a Dynamic Mode Decomposition (DMD of the temperature and velocity fields recovers the low dimensional system underlying reversals, finding specific modes which together are predictive of reversal direction.

  20. Effect of reversal of the flow direction on hydrodynamic characteristics and plants cultivated in constructed wetland systems

    Directory of Open Access Journals (Sweden)

    Gheila Corrêa Ferres Baptestini

    2016-01-01

    Full Text Available The objective of the present study was to evaluate the effect of reversal of the flow direction, when used the surface flow as an operating criteria, on hydrodynamic characteristics and plants grown in horizontal subsurface-flow constructed wetland systems (HSF-CWs. For this purpose, six HSF-CWs were used: two non-cultivated (HSF-CWs 1 and 4, two cultivated with Tifton 85 grass (Cynodon spp. (HSF-CWs 2 and 5 and two cultivated with Alternanthera (Alternanthera philoxeroides (HSF-CWs 3 and 6. It was made a reversal in the flow direction of the HSF-CWs 1, 2 and 3. The reversal of the wastewater flow direction was performed when the superficial flow of the wastewater applied (SF reached 50% of the length of the HSF-CWs. There was a single reversal for each system, on different dates. Reversing the flow direction promoted distinction on the dry matter yield of Tifton 85 grass. This was not observed in HSF-CWs cultivated with Alternanthera. The reversal of the wastewater flow direction promoted, in principle, the extinction of the SF advance in the HSF-CWs, but did not prevent its return. Waiting for the SF to reach 50% of the length was not the best criterion for reversing the flow direction.

  1. Determination of maximum reactor power level consistent with the requirement that flow reversal occurs without fuel damage

    International Nuclear Information System (INIS)

    Rao, D.V.; Darby, J.L.; Ross, S.B.; Clark, R.A.

    1990-01-01

    The High Flux Beam Reactor (HFBR) operated by Brookhaven National Laboratory (BNL) employs forced downflow for heat removal during normal operation. In the event of total loss of forced flow, the reactor will shutdown and the flow reversal valves open. When the downward core flow becomes sufficiently small then the opposing thermal buoyancy induces flow reversal leading to decay heat removal by natural convection. There is some uncertainty as to whether the natural circulation is adequate for decay heat removal after 60 MW operation. BNL- staff carried out a series of calculations to establish the adequacy of flow reversal to remove decay heat. Their calculations are based on a natural convective CHF model. The primary purpose of the present calculations is to review the accuracy and applicability of Fauske's CHF model for the HFBR, and the assumptions and methodology employed by BNL-staff to determine the heat removal limit in the HFBR during a flow reversal and natural convection situation

  2. Reversing flow catalytic converter for a natural gas/diesel dual fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, E.; Checkel, M.D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Hayes, R.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Zheng, M.; Mirosh, E. [Alternative Fuel Systems Inc., Calgary, AB (Canada)

    2001-07-01

    An experimental and modelling study was performed for a reverse flow catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter had a segmented ceramic monolith honeycomb substrate and a catalytic washcoat containing a predominantly palladium catalyst. A one-dimensional single channel model was used to simulate the operation of the converter. The kinetics of the CO and methane oxidation followed first-order behaviour. The activation energy for the oxidation of methane showed a change with temperature, dropping from a value of 129 to 35 kJ/mol at a temperature of 874 K. The reverse flow converter was able to achieve high reactor temperature under conditions of low inlet gas temperature, provided that the initial reactor temperature was sufficiently high. (author)

  3. RELAP5 analyses of two hypothetical flow reversal events for the advanced neutron source reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N.C.J.; Wendel, M.W.; Yoder, G.L. Jr. [Oak Ridge National Lab., TN (United States)

    1995-09-01

    This paper presents RELAP5 results of two hypothetical, low flow transients analyzed as part of the Advanced Neutron Source Reactor safety program. The reactor design features four independent coolant loops (three active and one in standby), each containing a main curculation pump (with battery powered pony motor), heat exchanger, an accumulator, and a check valve. The first transient assumes one of these pumps fails, and additionally, that the check valve in that loop remains stuck in the open position. This accident is considered extremely unlikely. Flow reverses in this loop, reducing the core flow because much of the coolant is diverted from the intact loops back through the failed loop. The second transient examines a 102-mm-diam instantaneous pipe break near the core inlet (the worst break location). A break is assumed to occur 90 s after a total loss-of-offsite power. Core flow reversal occurs because accumulator injection overpowers the diminishing pump flow. Safety margins are evaluated against four thermal limits: T{sub wall}=T{sub sat}, incipient boiling, onset of significant void, and critical heat flux. For the first transient, the results show that these limits are not exceeded (at a 95% non-exceedance probability level) if the pony motor battery lasts 30 minutes (the present design value). For the second transient, the results show that the closest approach of the fuel surface temperature to the local saturation temperature during core flow reversal is about 39{degrees}C. Therefore the fuel remains cool during this transient. Although this work is done specifically for the ANSR geometry and operating conditions, the general conclusions may be applicable to other highly subcooled reactor systems.

  4. Experimental investigation of the check valve behaviour when the flow is reversing

    Directory of Open Access Journals (Sweden)

    Himr D.

    2017-01-01

    Full Text Available Check valve in a pipeline is supposed to prevent the reverse flow and to allow the flow in the positive direction. The construction of check valves follows these requirements, but the check valve must not cause pressure pulsations in transients. It means when the fluid is accelerating or decelerating. The article describes an experimental investigation of a swing check valve when the flow is changing its direction. The check valve was placed in an experimental circuit, where the pressure on the upstream and downstream side of the valve was measured and the current value of flow rate was determined. The goal was to simulate conditions in the real system, where the check valve slam had been observed.

  5. Plasma-liquid system with reverse vortex flow of 'tornado' type (TORNADO-LE)

    International Nuclear Information System (INIS)

    Nedybalyuk, O.A.; Chernyak, V.Ya.; Olszewski, S.V.

    2010-01-01

    The results of experimental investigations of the plasma in plasma-liquid system with reverse vortex flow of 'tornado' type are presented. Volt-ampere characteristic of discharge in the current range from 200 to 400 mA were measured. Emission spectra of plasma in range from 200 to 1100 nm were measured. Excitation temperatures (electronic T e * , vibrational T v * and rotational T r * ) were obtained. Emission spectra of hydroxyl OH were calculated.

  6. Yield of reversible colloidal gels during flow start-up: release from kinetic arrest.

    Science.gov (United States)

    Johnson, Lilian C; Landrum, Benjamin J; Zia, Roseanna N

    2018-06-05

    Yield of colloidal gels during start-up of shear flow is characterized by an overshoot in shear stress that accompanies changes in network structure. Prior studies of yield of reversible colloidal gels undergoing strong flow model the overshoot as the point at which network rupture permits fluidization. However, yield under weak flow, which is of interest in many biological and industrial fluids shows no such disintegration. The mechanics of reversible gels are influenced by bond strength and durability, where ongoing rupture and re-formation impart aging that deepens kinetic arrest [Zia et al., J. Rheol., 2014, 58, 1121], suggesting that yield be viewed as release from kinetic arrest. To explore this idea, we study reversible colloidal gels during start-up of shear flow via dynamic simulation, connecting rheological yield to detailed measurements of structure, bond dynamics, and potential energy. We find that pre-yield stress grows temporally with the changing roles of microscopic transport processes: early time behavior is set by Brownian diffusion; later, advective displacements permit relative particle motion that stretches bonds and stores energy. Stress accumulates in stretched, oriented bonds until yield, which is a tipping point to energy release, and is passed with a fully intact network, where the loss of very few bonds enables relaxation of many, easing glassy arrest. This is immediately followed by a reversal to growth in potential energy during bulk plastic deformation and condensation into larger particle domains, supporting the view that yield is an activated release from kinetic arrest. The continued condensation of dense domains and shrinkage of network surfaces, along with a decrease in the potential energy, permit the gel to evolve toward more complete phase separation, supporting our view that yield of weakly sheared gels is a 'non-equilibrium phase transition'. Our findings may be particularly useful for industrial or other coatings, where weak

  7. Performance characteristics of axisymmetric venturi-like reverse-flow diverters. Consolidated Fuel Reprocessing Program

    International Nuclear Information System (INIS)

    Smith, G.V.; Counce, R.M.

    1984-01-01

    This paper presents experimental and model-predicted pressure-flow characteristics of axisymmetric venturi-like reverse-flow diverters (RFDs), the key component of fluid pumping systems utilized for the transport of hazardous fluids. The effects of several key geometric parameters, operating conditions, and fluid properties on the performance of the RFD are presented and compared to model predictions. The results indicate good agreement between data and theory over a large portion of the range of variables studied. Cavitation is observed to be the primary factor in limiting the performance of the RFD at small values of load impedances

  8. Validity of peak expiratory flow measurement in assessing reversibility of airflow obstruction.

    Science.gov (United States)

    Dekker, F W; Schrier, A C; Sterk, P J; Dijkman, J H

    1992-01-01

    BACKGROUND: Assessing the reversibility of airflow obstruction by peak expiratory (PEF) measurements would be practicable in general practice, but its usefulness has not been investigated. METHODS: PEF measurements were performed (miniWright peak flow meter) in 73 general practice patients (aged 40 to 84) with a history of asthma or chronic obstructive lung disease before and after 400 micrograms inhaled sulbutamol. The change in PEF was compared with the change in forced expiratory volume in one second (FEV1). Reversible airflow obstruction was analysed in two ways according to previous criteria. When defined as a 9% or greater increase in FEV1 expressed as a percentage of predicted values reversibility was observed in 42% of patients. Relative operating characteristic analysis showed that an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (the sensitivity and specificity of an increase of 60 l/min in detecting a 9% or more increase in FEV1 as a percentage of predicted values were 68% and 93% respectively, with a positive predictive value of 87%). When defined as an increase of 190 ml or more in FEV1, reversible airflow obstruction was observed in 53% of patients. Again an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (sensitivity 56%, specificity 94%, and positive predictive value 92%). CONCLUSION: Absolute changes in PEF can be used as a simple technique to diagnose reversible airflow obstruction in patients from general practice. PMID:1519192

  9. Reverse capillary flow of condensed water through aligned multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Yun, Jongju; Jeon, Wonjae; Alam Khan, Fakhre; Lee, Jinkee; Baik, Seunghyun

    2015-01-01

    Molecular transport through nanopores has recently received considerable attention as a result of advances in nanofabrication and nanomaterial synthesis technologies. Surprisingly, water transport investigations through carbon nanochannels resulted in two contradicting observations: extremely fast transport or rejection of water molecules. In this paper, we elucidate the mechanism of impeded water vapor transport through the interstitial space of aligned multiwalled carbon nanotubes (aligned-MWCNTs)—capillary condensation, agglomeration, reverse capillary flow, and removal by superhydrophobicity at the tip of the nanotubes. The origin of separation comes from the water’s phase change from gas to liquid, followed by reverse capillary flow. First, the saturation water vapor pressure is decreased in a confined space, which is favorable for the phase change of incoming water vapor into liquid drops. Once continuous water meniscus is formed between the nanotubes by the adsoprtion and agglomeration of water molecules, a high reverse Laplace pressure is induced in the mushroom-shaped liquid meniscus at the entry region of the aligned-MWCNTs. The reverse Laplace pressure can be significantly enhanced by decreasing the pore size. Finally, the droplets pushed backward by the reverse Laplace pressure can be removed by superhydrophobicity at the tip of the aligned-MWCNTs. The analytical analysis was also supported by experiments carried out using 4 mm-long aligned-MWCNTs with different intertube distances. The water rejection rate and the separation factor increased as the intertube distance decreased, resulting in 90% and 10, respectively, at an intertube distance of 4 nm. This mechanism and nanotube membrane may be useful for energy-efficient water vapor separation and dehumidification. (paper)

  10. Extensive young silicic volcanism produces large deep submarine lava flows in the NE Lau Basin

    Science.gov (United States)

    Embley, Robert W.; Rubin, Kenneth H.

    2018-04-01

    New field observations reveal that extensive (up to 402 km2) aphyric, glassy dacite lavas were erupted at multiple sites in the recent past in the NE Lau basin, located about 200 km southwest of Samoa. This discovery of volumetrically significant and widespread submarine dacite lava flows extends the domain for siliceous effusive volcanism into the deep seafloor. Although several lava flow fields were discovered on the flank of a large silicic seamount, Niuatahi, two of the largest lava fields and several smaller ones ("northern lava flow fields") were found well north of the seamount. The most distal portion of the northernmost of these fields is 60 km north of the center of Niuatahi caldera. We estimate that lava flow lengths from probable eruptive vents to the distal ends of flows range from a few km to more than 10 km. Camera tows on the shallower, near-vent areas show complex lava morphology that includes anastomosing tube-like pillow flows and ropey surfaces, endogenous domes and/or ridges, some with "crease-like" extrusion ridges, and inflated lobes with extrusion structures. A 2 × 1.5 km, 30-m deep depression could be an eruption center for one of the lava flow fields. The Lau lava flow fields appear to have erupted at presumptive high effusion rates and possibly reduced viscosity induced by presumptive high magmatic water content and/or a high eruption temperature, consistent with both erupted composition ( 66% SiO2) and glassy low crystallinity groundmass textures. The large areal extent (236 km2) and relatively small range of compositional variation ( σ = 0.60 for wt% Si02%) within the northern lava flow fields imply the existence of large, eruptible batches of differentiated melt in the upper mantle or lower crust of the NE Lau basin. At this site, the volcanism could be controlled by deep crustal fractures caused by the long-term extension in this rear-arc region. Submarine dacite flows exhibiting similar morphology have been described in ancient

  11. Voluminous lava flow from Axial Seamount's south rift constrains extension rate on northern Vance Segment

    Science.gov (United States)

    Le Saout, M.; Clague, D. A.; Paduan, J. B.

    2017-12-01

    Axial Seamount is characterized by a robust magma supply resulting from the interaction between the Cobb hotspot and the Juan de Fuca Ridge. During the last two decades, magmatic activity was focused within the summit caldera and upper and middle portions of the two rift zones, with eruptions in 1998, 2011, and 2015. However, the distal ends of both rift zones have experienced numerous eruptions in the past. The most voluminous flows are located near the extreme ends, greater than 40 kilometers from the caldera. Where Axial's South Rift Zone overlaps with the Vance Segment of the Juan de Fuca Ridge, the 2015 MBARI expedition mapped 16 km2 of the seafloor with our AUV, and collected 33 rocks and 33 sediment cores during two ROV dives. The data were used to confirm the boundaries of an extensive flow tentatively identified using modern ship based bathymetry. This flow is 18 km wide and 6 km long for a total surface area of 63 km2. The flow is modified by superficial ( 5 m deep) and deep (25 to 45 m deep) subsidence pits, with the deepest pits giving an indication of the minimum thickness of the flow. The maximum thickness of 100 m is measured at the margins of the flow. We thus estimate a volume between 2.5 and 6 km3, making this flow the most voluminous known on the global mid ocean ridge system. The minimum volume is equivalent to the present volume of the summit caldera. Radiocarbon ages of foraminifera from the basal sections of sediment cores suggest that this flow is 1000 years old. This flow travelled east and partially filled the axial valley of the adjacent Vance Segment. Since emplacement, this part of the flow has experienced deformation by fissures and faults aligned with the trend of the Vance Segment. The horizontal extension across these features allows us to estimate a local deformation rate of 3 cm/yr of tectonic extension on the northern end of Vance Segment during the last 1000 years.

  12. Turbulence, transport, and zonal flows in the Madison symmetric torus reversed-field pinch

    Science.gov (United States)

    Williams, Z. R.; Pueschel, M. J.; Terry, P. W.; Hauff, T.

    2017-12-01

    The robustness and the effect of zonal flows in trapped electron mode (TEM) turbulence and Ion Temperature Gradient (ITG) turbulence in the reversed-field pinch (RFP) are investigated from numerical solutions of the gyrokinetic equations with and without magnetic external perturbations introduced to model tearing modes. For simulations without external magnetic field perturbations, zonal flows produce a much larger reduction of transport for the density-gradient-driven TEM turbulence than they do for the ITG turbulence. Zonal flows are studied in detail to understand the nature of their strong excitation in the RFP and to gain insight into the key differences between the TEM- and ITG-driven regimes. The zonal flow residuals are significantly larger in the RFP than in tokamak geometry due to the low safety factor. Collisionality is seen to play a significant role in the TEM zonal flow regulation through the different responses of the linear growth rate and the size of the Dimits shift to collisionality, while affecting the ITG only minimally. A secondary instability analysis reveals that the TEM turbulence drives zonal flows at a rate that is twice that of the ITG turbulence. In addition to interfering with zonal flows, the magnetic perturbations are found to obviate an energy scaling relation for fast particles.

  13. Passive Flap Actuation by Reversing Flow in Laminar Boundary Layer Separation

    Science.gov (United States)

    Parsons, Chase; Lang, Amy; Santos, Leo; Bonacci, Andrew

    2017-11-01

    Reducing the flow separation is of great interest in the field of fluid mechanics in order to reduce drag and improve the overall efficiency of aircraft. This project seeks to investigate passive flow control using shark inspired microflaps in laminar boundary layer separation. This study aims to show that whether a flow is laminar or turbulent, laminar and 2D or turbulent and 3D, microflaps actuated by reversing flow is a robust means of controlling flow separation. In order to generate a controlled adverse pressure gradient, a rotating cylinder induces separation at a chosen location on a flat plate boundary layer with Re above 10000. Within this thick boundary layer, digital particle image velocimetry is used to map the flow. This research can be used in the future to better understand the nature of the bristling shark scales and its ability to passively control separation. Results show that microflaps successfully actuated due to backflow and that this altered the formation of flow separation. I would like to thank the NSF for REU Grant EEC 1659710 and the Army Research Office for funding this project.

  14. Spontaneous generation and reversals of mean flows in a convectively-generated internal gravity wave field

    Science.gov (United States)

    Couston, Louis-Alexandre; Lecoanet, Daniel; Favier, Benjamin; Le Bars, Michael

    2017-11-01

    We investigate via direct numerical simulations the spontaneous generation and reversals of mean zonal flows in a stably-stratified fluid layer lying above a turbulent convective fluid. Contrary to the leading idealized theories of mean flow generation by self-interacting internal waves, the emergence of a mean flow in a convectively-generated internal gravity wave field is not always possible because nonlinear interactions of waves of different frequencies can disrupt the mean flow generation mechanism. Strong mean flows thus emerge when the divergence of the Reynolds stress resulting from the nonlinear interactions of internal waves produces a strong enough anti-diffusive acceleration for the mean flow, which, as we will demonstrate, is the case when the Prandtl number is sufficiently low, or when the energy input into the internal wavefield by the convection and density stratification are sufficiently large. Implications for mean zonal flow production as observed in the equatorial stratospheres of the Earth, Saturn and Jupiter, and possibly occurring in other geophysical systems such as planetary and stellar interiors will be briefly discussed. Funding provided by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program through Grant Agreement No. 681835-FLUDYCO-ERC-2015-CoG.

  15. On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

    Directory of Open Access Journals (Sweden)

    Aouss Gabash

    2016-02-01

    Full Text Available It has recently been shown that using battery storage systems (BSSs to provide reactive power provision in a medium-voltage (MV active distribution network (ADN with embedded wind stations (WSs can lead to a huge amount of reverse power to an upstream transmission network (TN. However, unity power factors (PFs of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I, we aim to further explore the pure reactive power potential of WSs (i.e., without BSSs by investigating the issue of variable reverse power flow under different limits on PFs in an electricity market model. The main contributions of this work are summarized as follows: (1 Introducing the reactive power capability of WSs in the optimization model of the active-reactive optimal power flow (A-R-OPF and highlighting the benefits/impacts under different limits on PFs. (2 Investigating the impacts of different agreements for variable reverse power flow on the operation of an ADN under different demand scenarios. (3 Derivation of the function of reactive energy losses in the grid with an equivalent-π circuit and comparing its value with active energy losses. (4 Balancing the energy curtailment of wind generation, active-reactive energy losses in the grid and active-reactive energy import-export by a meter-based method. In Part-II, the potential of the developed model is studied through analyzing an electricity market model and a 41-bus network with different locations of WSs.

  16. CO2 saturated water as two-phase flow for fouling control in reverse electrodialysis.

    Science.gov (United States)

    Moreno, J; de Hart, N; Saakes, M; Nijmeijer, K

    2017-11-15

    When natural feed waters are used in the operation of a reverse electrodialysis (RED) stack, severe fouling on the ion exchange membranes and spacers occurs. Fouling of the RED stack has a strong influence on the gross power density output; which can decrease up to 50%. Moreover, an increase in the pressure loss occurs between the feed water inlet and outlet, increasing the pumping energy and thus decreasing the net power density that can be obtained. In this work, we extensively investigated the use of CO 2 saturated water as two-phase flow cleaning for fouling mitigation in RED using natural feed waters. Experiments were performed in the REDstack research facility located at the Afsluitdijk (the Netherlands) using natural feed waters for a period of 60 days. Two different gas combinations were experimentally investigated, water/air sparging and water/CO 2 (saturated) injection. Air is an inert gas mixture and induces air sparging in the stack. In the case of CO 2 , nucleation, i.e. the spontaneous formation of bubbles, occurs at the spacer filaments due to depressurization of CO 2 saturated water, inducing cleaning. Results showed that stacks equipped with CO 2 saturated water can produce an average net power density of 0.18 W/m 2 under real fouling conditions with minimal pre-treatment and at a low outside temperature of only 8 °C, whereas the stacks equipped with air sparging could only produce an average net power density of 0.04 W/m 2 . Electrochemical impedance spectroscopy measurements showed that the stacks equipped with air sparging increased in stack resistance due to the presence of stagnant bubbles remaining in the stack after every air injection. Furthermore, the introduction of CO 2 gas in the feed water introduces a pH decrease in the system (carbonated solution) adding an additional cleaning effect in the system, thus avoiding the use of environmentally unwanted cleaning chemicals. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All

  17. INVESTIGATION RESULTS PERTAINING TO DETERMINATION OF REVERSE FLOW PRESSURE ON TREATED FLAT SURFACE

    Directory of Open Access Journals (Sweden)

    A. N. Zhuk

    2018-01-01

    Full Text Available The executed investigations have shown that it is possible to prepare sheet-like material for laser cutting economically viable and with small amount of power expenditure while using reverse jet cleaning for surface treatment. As compared to conventional jet cleaning technologies efficiency of the reverse jet cleaning is attributed to significant pressure increase (by 25–50 % when the jet is interacting with the treated surface. The paper proposes a mathematical model on the basis of approximate energy method (upper-bound method and the model is used for calculation of fracture pressure due to action of the reverse jet on the treated surface which consists of a corrosion deposit layer. A variational problem was solved within a framework of the developed model and the problem solution has made it possible to obtain a theoretical dependence for calculation of minimum fracture pressure value pmin in the point reverse jet impact with a barrier oretical dependence and it has taken into account yielding point of the deformed material ss, density of fractured material med material r, jet velocity uстр and parameter of reverse flowing – jet reduction ratio l. Comparison theoretical data and experimental ones (experimental data have been obtained while using a differential pressure transducer ЭДП-30 and a spring dynamometer with measuring limits 25 and 80 MPa, respectively has shown difference by 4–15 %. Determined insignificant difference between a theory and an experiment demonstrates that the obtained theoretical dependence is considered as a quite correct one and it can be used in engineering practice for prediction of power and kinematics parameters which are necessary for selection of the required pump equipment designed for realization of reverse-jet cleaning process.

  18. Research on external flow field of a car based on reverse engineering

    Science.gov (United States)

    Hu, Shushan; Liu, Ronge

    2018-05-01

    In this paper, the point cloud data of FAW-VOLKSWAGEN car body shape is obtained by three coordinate measuring instrument and laser scanning method. The accurate three dimensional model of the car is obtained using CATIA software reverse modelling technology. The car body is gridded, the calculation field and boundary condition type of the car flow field are determined, and the numerical simulation is carried out in Hyper Mesh software. The pressure cloud diagram, velocity vector diagram, air resistance coefficient and lift coefficient of the car are obtained. The calculation results reflect the aerodynamic characteristics of the car's external flow field. The motion of the separation flow on the surface of the vehicle body is well simulated, and the area where the vortex motion is relatively intense has been determined. The results provide a theoretical basis for improving and optimizing the body shape.

  19. Extreme concentration fluctuations due to local reversibility of mixing in turbulent flows

    Science.gov (United States)

    Xia, Hua; Francois, Nicolas; Punzmann, Horst; Szewc, Kamil; Shats, Michael

    2018-05-01

    Mixing of a passive scalar in a fluid (e.g. a radioactive spill in the ocean) is the irreversible process towards homogeneous distribution of a substance. In a moving fluid, due to the chaotic advection [H. Aref, J. Fluid Mech. 143 (1984) 1; J. M. Ottino, The Kinematics of Mixing: Stretching,Chaos and Transport (Cambridge University Press, Cambridge, 1989)] mixing is much faster than if driven by molecular diffusion only. Turbulence is known as the most efficient mixing flow [B. I. Shraiman and E. D. Siggia, Nature 405 (2000) 639]. We show that in contrast to spatially periodic flows, two-dimensional turbulence exhibits local reversibility in mixing, which leads to the generation of unpredictable strong fluctuations in the scalar concentration. These fluctuations can also be detected from the analysis of the fluid particle trajectories of the underlying flow.

  20. Network modeling for reverse flows of end-of-life vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Ene, Seval; Öztürk, Nursel

    2015-04-15

    Highlights: • We developed a network model for reverse flows of end-of-life vehicles. • The model considers all recovery operations for end-of-life vehicles. • A scenario-based model is used for uncertainty to improve real case applications. • The model is adequate to real case applications for end-of-life vehicles recovery. • Considerable insights are gained from the model by sensitivity analyses. - Abstract: Product recovery operations are of critical importance for the automotive industry in complying with environmental regulations concerning end-of-life products management. Manufacturers must take responsibility for their products over the entire life cycle. In this context, there is a need for network design methods for effectively managing recovery operations and waste. The purpose of this study is to develop a mathematical programming model for managing reverse flows in end-of-life vehicles’ recovery network. A reverse flow is the collection of used products from consumers and the transportation of these products for the purpose of recycling, reuse or disposal. The proposed model includes all operations in a product recovery and waste management network for used vehicles and reuse for vehicle parts such as collection, disassembly, refurbishing, processing (shredding), recycling, disposal and reuse of vehicle parts. The scope of the network model is to determine the numbers and locations of facilities in the network and the material flows between these facilities. The results show the performance of the model and its applicability for use in the planning of recovery operations in the automotive industry. The main objective of recovery and waste management is to maximize revenue and minimize pollution in end-of-life product operations. This study shows that with an accurate model, these activities may provide economic benefits and incentives in addition to protecting the environment.

  1. Network modeling for reverse flows of end-of-life vehicles

    International Nuclear Information System (INIS)

    Ene, Seval; Öztürk, Nursel

    2015-01-01

    Highlights: • We developed a network model for reverse flows of end-of-life vehicles. • The model considers all recovery operations for end-of-life vehicles. • A scenario-based model is used for uncertainty to improve real case applications. • The model is adequate to real case applications for end-of-life vehicles recovery. • Considerable insights are gained from the model by sensitivity analyses. - Abstract: Product recovery operations are of critical importance for the automotive industry in complying with environmental regulations concerning end-of-life products management. Manufacturers must take responsibility for their products over the entire life cycle. In this context, there is a need for network design methods for effectively managing recovery operations and waste. The purpose of this study is to develop a mathematical programming model for managing reverse flows in end-of-life vehicles’ recovery network. A reverse flow is the collection of used products from consumers and the transportation of these products for the purpose of recycling, reuse or disposal. The proposed model includes all operations in a product recovery and waste management network for used vehicles and reuse for vehicle parts such as collection, disassembly, refurbishing, processing (shredding), recycling, disposal and reuse of vehicle parts. The scope of the network model is to determine the numbers and locations of facilities in the network and the material flows between these facilities. The results show the performance of the model and its applicability for use in the planning of recovery operations in the automotive industry. The main objective of recovery and waste management is to maximize revenue and minimize pollution in end-of-life product operations. This study shows that with an accurate model, these activities may provide economic benefits and incentives in addition to protecting the environment

  2. Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

    Science.gov (United States)

    Hashimoto, Junichiro; Ito, Sadayoshi

    2015-07-01

    Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function. © 2015 American Heart Association

  3. Evidence from lava flows for complex polarity transitions: The new composite Steens Mountain reversal record

    Science.gov (United States)

    Jarboe, Nicholas A.; Coe, Robert S.; Glen, Jonathan M. G.

    2011-01-01

    Geomagnetic polarity transitions may be significantly more complex than are currently depicted in many sedimentary and lava-flow records. By splicing together paleomagnetic results from earlier studies at Steens Mountain with those from three newly studied sections of Oregon Plateau flood basalts at Catlow Peak and Poker Jim Ridge 70–90 km to the southeast and west, respectively, we provide support for this interpretation with the most detailed account of a magnetic field reversal yet observed in volcanic rocks. Forty-five new distinguishable transitional (T) directions together with 30 earlier ones reveal a much more complex and detailed record of the 16.7 Ma reversed (R)-to-normal (N) polarity transition that marks the end of Chron C5Cr. Compared to the earlier R-T-N-T-N reversal record, the new record can be described as R-T-N-T-N-T-R-T-N. The composite record confirms earlier features, adds new west and up directions and an entire large N-T-R-T segment to the path, and fills in directions on the path between earlier directional jumps. Persistent virtual geomagnetic pole (VGP) clusters and separate VGPs have a preference for previously described longitudinal bands from transition study compilations, which suggests the presence of features at the core–mantle boundary that influence the flow of core fluid and distribution of magnetic flux. Overall the record is consistent with the generalization that VGP paths vary greatly from reversal to reversal and depend on the location of the observer. Rates of secular variation confirm that the flows comprising these sections were erupted rapidly, with maximum rates estimated to be 85–120 m ka−1 at Catlow and 130–195 m ka−1 at Poker Jim South. Paleomagnetic poles from other studies are combined with 32 non-transitional poles found here to give a clockwise rotation of the Oregon Plateau of 11.4°± 5.6° with respect to the younger Columbia River Basalt Group flows to the north and 14.5°± 4.6° with respect

  4. Maintenance of differentiation potential of human bone marrow mesenchymal stem cells immortalized by human telomerase reverse transcriptase gene despite of extensive proliferation

    International Nuclear Information System (INIS)

    Abdallah, Basem M.; Haack-Sorensen, Mandana; Burns, Jorge S.; Elsnab, Birgitte; Jakob, Franz; Hokland, Peter; Kassem, Moustapha

    2005-01-01

    Human bone marrow mesenchymal stem cells (hMSC) represent a population of stem cells that are capable of differentiation into multiple lineages. However, these cells exhibit senescence-associated growth arrest and phenotypic changes during long-term in vitro culture. We have recently demonstrated that overexpression of human telomerase reverse transcriptase (hTERT) in hMSC reconstitutes telomerase activity and extends life span of the cells [Nat. Biotechnol. 20 (2002) 592]. In the present study, we have performed extensive characterization of three independent cell lines derived from the parental hMSC-TERT cell line based on different plating densities during expansion in culture: 1:2 (hMSC-TERT2), 1:4 (hMSC-TERT4), and 1:20 (hMSC-TERT20). The 3 cell lines exhibited differences in morphology and growth rates but they all maintained the characteristics of self-renewing stem cells and the ability to differentiate into multiple mesoderm-type cell lineages: osteoblasts, adipocytes, chondrocytes, and endothelial-like cells over a 3-year period in culture. Also, surface marker studies using flow cytometry showed a pattern similar to that known from normal hMSC. Thus, telomerization of hMSC by hTERT overexpression maintains the stem cell phenotype of hMSC and it may be a useful tool for obtaining enough number of cells with a stable phenotype for mechanistic studies of cell differentiation and for tissue engineering protocols

  5. Network modeling for reverse flows of end-of-life vehicles.

    Science.gov (United States)

    Ene, Seval; Öztürk, Nursel

    2015-04-01

    Product recovery operations are of critical importance for the automotive industry in complying with environmental regulations concerning end-of-life products management. Manufacturers must take responsibility for their products over the entire life cycle. In this context, there is a need for network design methods for effectively managing recovery operations and waste. The purpose of this study is to develop a mathematical programming model for managing reverse flows in end-of-life vehicles' recovery network. A reverse flow is the collection of used products from consumers and the transportation of these products for the purpose of recycling, reuse or disposal. The proposed model includes all operations in a product recovery and waste management network for used vehicles and reuse for vehicle parts such as collection, disassembly, refurbishing, processing (shredding), recycling, disposal and reuse of vehicle parts. The scope of the network model is to determine the numbers and locations of facilities in the network and the material flows between these facilities. The results show the performance of the model and its applicability for use in the planning of recovery operations in the automotive industry. The main objective of recovery and waste management is to maximize revenue and minimize pollution in end-of-life product operations. This study shows that with an accurate model, these activities may provide economic benefits and incentives in addition to protecting the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Non-contact flow gauging for the extension and development of rating curves

    Science.gov (United States)

    Perks, Matthew; Large, Andy; Russell, Andy

    2015-04-01

    Accurate measurement of river discharge is fundamental to understanding hydrological processes, associated hazards and ecological responses within fluvial systems. Established protocols for determining river discharge are partial, predominantly invasive and logistically difficult during high flows. There is demand for new methods for accurate quantification of flow velocity under high-flow/flood conditions to in turn enable better post-event reconstruction of peak discharge. As a consequence considerable effort has been devoted to the development of innovative technologies for the representation of flow in open channels. Remotely operated fixed and mobile systems capable of providing quantitative estimates of instantaneous and time-averaged flow characteristics using non-contact methods has been a major development. Amongst the new approaches for stand-alone continuous monitoring of surface flows is Large Scale Particle Image Velocimetry (LSPIV). Here we adapt the LSPIV concept, to provide continuous discharge measurements in non-uniform channels with complex flow conditions. High Definition videos (1080p; 30fps) of the water surface are acquired at 5 minute intervals. The image is rectified to correct for perspective distortion using a new, open source tool which minimises errors resulting from oblique image capture. Naturally occurring artefacts on the water surface (e.g. bubbles, debris, etc.) are tracked with the Kanade-Lucas-Tomasi (KLT) algorithm. The data generated is in the form of a complex surface water velocity field which can be interrogated to extract a range of hydrological information such as the streamwise velocity at a cross-section of interest, or even allow the interrogation of hydrodynamic flow structures. Here we demonstrate that this approach is capable of generating river discharge data comparable to concurrent measurements made using existing, accepted technologies (e.g. ADCP). The outcome is better constraint and extension of rating curves

  7. Recleaning of HEPA filters by reverse flow - evaluation of the underlying processes and the cleaning technique

    International Nuclear Information System (INIS)

    Leibold, H.; Leiber, T.; Doeffert, I.; Wilhelm, J.G.

    1993-08-01

    HEPA filter operation at high concentrations of fine dusts requires the periodic recleaning of the filter units in their service locations. Due to the low mechanical stress induced during the recleaning process the regenration via low pressure reverse flow is a very suitable technique. Recleanability of HEPA filter had been attained for particle diameter >0,4 μm at air velocities up to 1 m/s, but filter clogging occurred in case of smaller particles. The recleaning forces are too weak for particles [de

  8. Entropy production in a cell and reversal of entropy flow as an anticancer therapy

    Institute of Scientific and Technical Information of China (English)

    Liao-fu LUO

    2009-01-01

    The entropy production rate of cancer cells is always higher than healthy cells in the case where no external field is applied. Different entropy production between two kinds of cells determines the direction of entropy flow among cells. The entropy flow is the carrier of information flow. The entropy flow from cancerous cells to healthy cells takes along the harmful information of cancerous cells, propagating its toxic action to healthy tissues. We demonstrate that a low-frequency and low- intensity electromagnetic field or ultrasound irradiation may increase the entropy production rate of a cell in normal tissue than that in cancer and consequently re- verse the direction of entropy current between two kinds of cells. The modification of the PH value of cells may also cause the reversal of the direction of entropy flow between healthy and cancerous cells. Therefore, the bio- logical tissue under the irradiation of an electromagnetic field or ultrasound or under the appropriate change of cell acidity can avoid the propagation of harmful infor- marion from cancer cells. We suggest that this entropy mechanism possibly provides a basis for a novel approach to anticancer therapy.

  9. Energetic atomic and molecular ions of ionospheric origin observed in distant magnetotail flow-reversal events

    Science.gov (United States)

    Christon, S. P.; Gloeckler, G.; Williams, D. J.; Mukai, T.; Mcentire, R. W.; Jacquey, C.; Angelopoulos, V.; Lui, A. T. Y.; Kokubun, S.; Fairfield, D. H.

    1994-01-01

    Energetic atomic (O(+1) and N(+1)) and molecular (O2(+1), NO(+1), and N2(+1)) ions of ionospheric origin were observed in Earth's magnetotail at X approximately -146 R(sub E) during two plasma sheet sunward/tailward flow-reversal events measured by instruments on the GEOTAIL spacecraft. These events were associated with concurrent ground-measured geomagnetic disturbance intensification at auroral-and mid-latitudes (Kp = 7(-)). Energetic ions in the sunward-component and tailward flows were from both the solar wind and ionosphere. Plasma and energetic ions participated in the flows. During tailward flow, ionospheric origin ion abundance ratios at approximately 200-900 km/s in the rest frame were N(+1)/O(+1) = approximately 25-30% and ((O2(+1), NO(+1), and N2(+1))/O(+1) = approximately 1-2%. We argue that tailward flow most likely initiated approximately 80-100 R(sub E) tailward of Earth and molecular ions were in the plasma sheet prior to geomagnetic intensification onset.

  10. The effect of flow and chemical corrosion in reverse osmosis over desalinated water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jae [Chunnam National Univ., Gwangju (Korea, Republic of); Pak, Byung Gu [Doosan Heavy Industry Co., Tongyoung (Korea, Republic of)

    2015-12-15

    Desalinated water produced by a reverse osmosis (RO) filtering method forms about 22% of total production of desalinated water in the world. However, the RO environment is very corrosive due to the presence of various chemicals for water treatment and the flow of sand particles leading to corrosion. Recently, there has been much effort to substitute cheaper and more corrosion resistant stainless steels for copper based alloys as a valve material in RO. Nevertheless, the effects of chemicals and particles on the corrosion of stainless steels have rarely been studied. Erosion phenomenon was detected under the condition with the flow rate of more than 8ms{sup -1} in spite of the absence of sand particles. In seawater containing sand particles, the erosion in stainless steels was accelerated further.

  11. Analysis of the Numerical Modelling of Turbulence in the Conical Reverse-Flow Cyclone

    Directory of Open Access Journals (Sweden)

    Inga Jakštonienė

    2011-02-01

    Full Text Available The paper describes the numerical modelling of the swirling fluid flow in the Stairmand cyclone (conical reverse-flow – CRF with tangential inlet (equipment for separating solid particles from the gaseous fluid flow. A review of experimental and theoretical papers is conducted introducing three-dimen­sional differential equations for transfer processes. The numerical modelling of the Stairmand cyclone the height of which is 0.75 m, diameter – 0.17 m, the height of a cylindrical part – 0.290 m, a conical part – 0,39 m and an inlet area is 0,085×0,032 m is presented. When governing three-dimensional fluid flow, transfer equations Navje-Stokes and Reynolds are solved using the finite volume method in a body-fitted co-ordinate system using standard k– e and RNG k– e model of turbulence. Modelling is realised for inlet velocity 4.64, 9.0 and 14.8 m/s (flow rate was 0.0112, 0.0245 and 0.0388 m3/s. The results obtained from the numerical tests have demonstrated that the RNG k– e model of turbulence yields a reasonably good prediction for highly swirling flows in cyclones: the presented numerical results (tangential and radial velocity profiles are compared with numerical and experimental data obtained by other authors. The mean relative error of ± 7,5% is found. Keywords: cyclone, solid particles, numerical modelling, turbulence, one-phase flow.DOI: 10.3846/mla.2010.085

  12. A highly reversible anthraquinone-based anolyte for alkaline aqueous redox flow batteries

    Science.gov (United States)

    Cao, Jianyu; Tao, Meng; Chen, Hongping; Xu, Juan; Chen, Zhidong

    2018-05-01

    The development of electroactive organic materials for use in aqueous redox flow battery (RFB) electrolytes is highly attractive because of their structural flexibility, low cost and sustainability. Here, we report on a highly reversible anthraquinone-based anolyte (1,8-dihydroxyanthraquinone, 1,8-DHAQ) for alkaline aqueous RFB applications. Electrochemical measurements reveal the substituent position of hydroxyl groups for DHAQ isomers has a significant impact on the redox potential, electrochemical reversibility and water-solubility. 1,8-DHAQ shows the highest redox reversibility and rapidest mass diffusion among five isomeric DHAQs. The alkaline aqueous RFB using 1,8-DHAQ as the anolyte and potassium ferrocyanide as the catholyte yields open-circuit voltage approaching 1.1 V and current efficiency and capacity retention exceeding 99.3% and 99.88% per cycle, respectively. This aqueous RFB produces a maximum power density of 152 mW cm-2 at 100% SOC and 45 °C. Choline hydroxide was used as a hydrotropic agent to enhance the water-solubility of 1,8-DHAQ. 1,8-DHAQ has a maximum solubility of 3 M in 1 M KOH with 4 M choline hydroxide.

  13. Reverse primary-side flow in steam generators during natural circulation cooling

    International Nuclear Information System (INIS)

    Stumpf, H.; Motley, F.; Schultz, R.; Chapman, J.; Kukita, Y.

    1987-01-01

    A TRAC model of the Large Scale Test Facility with a 3-tube steam-generator model was used to analyze natural-circulation test ST-NC-02. For the steady state at 100% primary mass inventory, TRAC was in excellent agreement with the natural-circulation flow rate, the temperature distribution in the steam-generator tubes, and the temperature drop from the hot leg to the steam-generator inlet plenum. TRAC also predicted reverse flow in the long tubes. At reduced primary mass inventories, TRAC predicted the three natural-circulation flow regimes: single phase, two phase, and reflux condensation. TRAC did not predict the cyclic fill-and-dump phenomenon seen briefly in the test. TRAC overpredicted the two-phase natural-circulation flow rate. Since the core is well cooled at this time, the result is conservative. An important result of the analysis is that TRAC was able to predict the core dryout and heatup at approximately the same primary mass inventory as in the test. 4 refs., 8 figs., 2 tabs

  14. A Novel Method of Protection to Prevent Reverse Power Flow Based on Neuro-Fuzzy Networks for Smart Grid

    Directory of Open Access Journals (Sweden)

    Ali Hadi Abdulwahid

    2018-04-01

    Full Text Available This paper addresses the energy challenges related to the weak protection of renewable energy from reverse energy flow and expanding access to high-quality energy at the same time. Furthermore, this paper focuses on participation in the global transition to clean and low-carbon energy systems. Moreover, the increased demand for renewable energy seems to likely depend on whether it will be possible to greatly accelerate rates of progress toward increased efficiency, de-carbonization, greater generating diversity and lower pollutant emissions. This paper focuses on the protection of renewable energy technologies because they can be particularly attractive in dispersed areas and therefore, represent an important option for rural areas that lack electrical energy and distribution infrastructure. This paper proposes an improved protection device for a reverse power protection system using a new intelligent decision support system (IDSS. The IDSS is a support system for decision making, which makes extensive use of artificial intelligence (AI techniques. The new method integrates the powerful specification for neural networks and fuzzy inference systems. The main advantage of this method is that it causes a decrease in the steady state oscillation for the reverse power relay. In addition, the proposed method has the ability to monitor extreme environmental conditions. The generator can be converted into a motor when the steam supply to a turbine is interrupted while the generator is still connected to a grid (or operates in parallel with another generator. As a result, the generator will become a synchronous motor and will actually cause significant mechanical damage. The reverse energy protection device should be included in the generator protection scheme. Smart grids use communication networks with sophisticated algorithms to ensure coordination between protection systems. ZigBee is a newly developed technology that can be used in wireless sensor

  15. Asian wild rice is a hybrid swarm with extensive gene flow and feralization from domesticated rice.

    Science.gov (United States)

    Wang, Hongru; Vieira, Filipe G; Crawford, Jacob E; Chu, Chengcai; Nielsen, Rasmus

    2017-06-01

    The domestication history of rice remains controversial, with multiple studies reaching different conclusions regarding its origin(s). These studies have generally assumed that populations of living wild rice, O. rufipogon , are descendants of the ancestral population that gave rise to domesticated rice, but relatively little attention has been paid to the origins and history of wild rice itself. Here, we investigate the genetic ancestry of wild rice by analyzing a diverse panel of rice genomes consisting of 203 domesticated and 435 wild rice accessions. We show that most modern wild rice is heavily admixed with domesticated rice through both pollen- and seed-mediated gene flow. In fact, much presumed wild rice may simply represent different stages of feralized domesticated rice. In line with this hypothesis, many presumed wild rice varieties show remnants of the effects of selective sweeps in previously identified domestication genes, as well as evidence of recent selection in flowering genes possibly associated with the feralization process. Furthermore, there is a distinct geographical pattern of gene flow from aus , indica , and japonica varieties into colocated wild rice. We also show that admixture from aus and indica is more recent than gene flow from japonica , possibly consistent with an earlier spread of japonica varieties. We argue that wild rice populations should be considered a hybrid swarm, connected to domesticated rice by continuous and extensive gene flow. © 2017 Wang et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Radiofrequency Ablation (RFA): Development of a Flow Model for Bovine Livers for Extensive Bench Testing

    International Nuclear Information System (INIS)

    Lubienski, Andreas; Bitsch, Rudi G.; Lubienski, Katrin; Kauffmann, Guenter; Duex, Markus

    2006-01-01

    Purpose. To develop a flow model for bovine livers for extensive bench testing of technical improvements or procedure-related developments of radiofrequency ablation excluding animal experiments. Methods. The perfusion of bovine livers directly from the slaughterhouse was simulated in a liver perfusion tank developed for the experimental work. The liver perfusion medium used was a Tyrode solution prepared in accordance with physiologic criteria (as for liver transplants) which was oxygenated by an oxygenator and heated to 36.5 deg. C. Portal vein circulation was regulated via a flow- and pressure-controlled pump and arterial circulation using a dialysis machine. Flow rate and pressure were adjusted as for the physiology of a human liver converted to bovine liver conditions. The fluid discharged from the liver was returned into the perfusion system through the vena cava. Extendable precision swivel arms with the radiofrequency probe attached were mounted on the liver perfusion tank. RFA was conducted with the RF3000 generator and a 2 cm LeVeen needle (Boston Scientific, Ratingen, Germany) in a three-dimensional grid for precise localization of the generated thermolesions. Results. Four bovine livers weighing 8.4 ± 0.4 kg each were prepared, connected to the perfusion system, and consecutively perfused for the experiments. Mean arterial flow was 569 ± 43 ml/min, arterial pressure 120 mmHg, portovenous flow 1440 ± 305 ml/min, and portal pressure 10 mmHg. Macroscopic evaluation after the experiments revealed no thrombi within the hepatic vessels. A total of 136 RF thermolesions were generated with an average number of 34 per liver. Mean RF duration was 2:59 ± 2:01 min:sec with an average baseline impedance of 28.2 ± 3.4 ohms. The mean diameter of the thermolesions along the puncture channel was 22.98 ± 4.34 mm and perpendicular to the channel was 23.27 ± 4.82 mm. Conclusion. Extracorporeal perfusion of bovine livers with consecutive standardized RF ablation was

  17. Reverse engineering of heavy-ion collisions: Unraveling initial conditions from anisotropic flow data

    International Nuclear Information System (INIS)

    Retinskaya, Ekaterina

    2014-01-01

    Ultra-Relativistic heavy-ion physics is a promising field of high energy physics connecting two fields: nuclear physics and elementary particle physics. Experimental achievements of the last years have provided an opportunity to study the properties of a new state of matter created in heavy-ion collisions called quark-gluon plasma. The initial state of two colliding nuclei is affected by fluctuations coming from wave- functions of nucleons. These fluctuations lead to the momentum anisotropy of the hadronic matter which is observed by the detectors. The system created in the collision behaves like a fluid, so the initial state is connected to the final state via hydrodynamic evolution. In this thesis we model the evolution with relativistic viscous hydrodynamics. Our results, combined with experimental data, give non trivial constraints on the initial state, thus achieving 'reverse engineering' of the heavy-ion collisions. The observable which characterizes the momentum anisotropy is the anisotropic flow v n . We present the first measurements of the first harmonic of the anisotropic flow called directed flow v 1 in Pb-Pb collisions at the LHC. We then perform the first viscous hydrodynamic modeling of directed flow and show that it is less sensitive to viscosity than higher harmonics. Comparison of these experimental data with the modeling allows to extract the values of the dipole asymmetry of the initial state, which provides constraints on the models of initial states. A prediction for directed flow v 1 in Au-Au collisions is also made for RHIC. We then perform a similar modeling of the second and third harmonics of the anisotropic flow, called respectively elliptic v 2 and triangular v 3 flow. A combined analysis of the elliptic and triangular flow data compared with viscous hydrodynamic calculations allows us to put constraints on initial ellipticity and triangularity of the system. These constraints are then used as a filter for different models of

  18. CO2 Dissociation by Low Current Gliding Discharge in the Reverse Vortex Flow

    Science.gov (United States)

    Gutsol, Alexander

    2012-10-01

    If performed with high energy efficiency, plasma-chemical dissociation of carbon dioxide can be a way of converting and storing energy when there is an excess of electric energy, for example generated by solar elements of wind turbines. CO2 dissociation with efficiency of up to 90% was reported earlier for low pressure microwave discharge in supersonic flow. A new plasma-chemical system uses a low current gliding discharge in the reverse vortex flow of plasma gas. The system is a development of the Gliding Arc in Tornado reactor. The system was used to study dissociation of CO2 in wide ranges of the following experimental parameters: reactor pressure (15-150 kPa), discharge current (50-500 mA), gas flow rate (3-30 liters per minute), and electrode gap length (1-10 cm). Additionally, the effect of thermal energy recuperation on CO2 dissociation efficiency was tested. Plasma chemical efficiency of CO2 dissociation is very low (about 3%) in a short discharge at low pressures (about 15 kPa) when it is defined by electronic excitation. The highest efficiency (above 40%) was reached at pressures 50-70 kPa in a long discharge with thermal energy recuperation. It means that the process is controlled by thermal dissociation with subsequent effective quenching. Plasma chemical efficiency was determined from the data of chromatographic analysis and oscilloscope electric power integration, and also was checked calorimetrically by the thermal balance of the system.

  19. Embolisation of the Gastroduodenal Artery is Not Necessary in the Presence of Reversed Flow Before Yttrium-90 Radioembolisation

    Energy Technology Data Exchange (ETDEWEB)

    Daghir, Ahmed A., E-mail: ahmeddaghir@doctors.net.uk [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom); Gungor, Hatice [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Haydar, Ali A. [Barts and the London NHS Trust, Department of Radiology (United Kingdom); Wasan, Harpreet S. [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Tait, Nicholas P. [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom)

    2012-08-15

    Introduction: The gastroduodenal artery (GDA) is usually embolised to avoid nontarget dispersal before yttrium-90 (Y{sup 90}) radioembolisation to treat liver metastases. In a minority of patients, there is retrograde flow in the GDA. The purpose of this study was to determine if there is any increased risk from maintaining a patent GDA in patients with reversed flow. Materials and Methods: A retrospective review was performed of all patients undergoing Y{sup 90} radioembolisation at our institution. The incidence of toxicities arising from nontarget radioembolisation by way of the GDA (gastric/duodenal ulceration, gastric/duodenal bleeding, and pancreatitis) and death occurring within 2 months of treatment were compared between the reversed and the antegrade GDA groups. Results: Ninety-two patients underwent preliminary angiography. Reversed GDA flow was found on angiography in 14.1% of cases; the GDA was not embolised in these patients. The GDA was coiled in 55.7% of patients with antegrade GDA flow to prevent inadvertent dispersal of radioembolic material. There was no increased toxicity related to nontarget dispersal by way of the GDA, or increased early mortality, in patients with reversed GDA flow (P > 0.05). Conclusion: In patients with reversed GDA flow, maintenance of a patent GDA before administration of Y{sup 90} radioembolisation does not increase the risk of toxicity from nontarget dispersal. Therapeutic injection, with careful monitoring to identify early vascular stasis, may be safely performed beyond the origin of the patent GDA. A patent GDA with reversed flow provides forward drive for infused particles and may allow alternative access to the hepatic circulation.

  20. Experimental and modelling study of reverse flow catalytic converters for natural gas/diesel dual fuel engine pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.

    2000-07-01

    There is renewed interest in the development of natural gas vehicles in response to the challenge to reduce urban air pollution and consumption of petroleum. The natural gas/diesel dual fuel engine is one way to apply natural gas to the conventional diesel engine. Dual fuel engines operating on natural gas and diesel emit less nitrogen oxides, and less carbon soot to the air compared to conventional diesel engines. The problem is that at light loads, fuel efficiency is reduced and emissions of hydrocarbons and carbon monoxide are increased. This thesis focused on control methods for emissions of hydrocarbons and carbon monoxide in the dual fuel engine at light loads. This was done by developing a reverse flow catalytic converter to complement dual fuel engine exhaust characteristics. Experimental measurements and numerical simulations of reverse flow catalytic converters were conducted. Reverse flow creates a high reactor temperature even when the engine is run at low exhaust temperature levels at light loads. The increase in reactor temperature from reverse flow could be 2 or 3 times higher than the adiabatic temperature increase, which is based on the reactor inlet temperature and concentration. This temperature makes it possible for greater than 90 per cent of the hydrocarbon and carbon monoxide to be converted with a palladium based catalyst. Reverse flow appears to be better than conventional unidirectional flow to deal with natural gas/diesel dual fuel engine pollution at light loads. Reverse flow could also maintain reactor temperature at over 800 K and hydrocarbon conversion at about 80 per cent during testing. The newly presented model simulates reactor performance with reasonable accuracy. Both carbon monoxide and methane oxidation over the palladium catalyst in excess oxygen and water were described using first order kinetics.

  1. Neutral Red and Ferroin as Reversible and Rapid Redox Materials for Redox Flow Batteries.

    Science.gov (United States)

    Hong, Jeehoon; Kim, Ketack

    2018-04-17

    Neutral red and ferroin are used as redox indicators (RINs) in potentiometric titrations. The rapid response and reversibility that are prerequisites for RINs are also desirable properties for the active materials in redox flow batteries (RFBs). This study describes the electrochemical properties of ferroin and neutral red as a redox pair. The rapid reaction rates of the RINs allow a cell to run at a rate of 4 C with 89 % capacity retention after the 100 th  cycle. The diffusion coefficients, electrode reaction rates, and solubilities of the RINs were determined. The electron-transfer rate constants of ferroin and neutral red are 0.11 and 0.027 cm s -1 , respectively, which are greater than those of the components of all-vanadium and Zn/Br 2 cells. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Reversible logic gates based on enzyme-biocatalyzed reactions and realized in flow cells: a modular approach.

    Science.gov (United States)

    Fratto, Brian E; Katz, Evgeny

    2015-05-18

    Reversible logic gates, such as the double Feynman gate, Toffoli gate and Peres gate, with 3-input/3-output channels are realized using reactions biocatalyzed with enzymes and performed in flow systems. The flow devices are constructed using a modular approach, where each flow cell is modified with one enzyme that biocatalyzes one chemical reaction. The multi-step processes mimicking the reversible logic gates are organized by combining the biocatalytic cells in different networks. This work emphasizes logical but not physical reversibility of the constructed systems. Their advantages and disadvantages are discussed and potential use in biosensing systems, rather than in computing devices, is suggested. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Effect of flow velocity, substrate concentration and hydraulic cleaning on biofouling of reverse osmosis feed channels

    KAUST Repository

    Radu, Andrea I.

    2012-04-01

    A two-dimensional mathematical model coupling fluid dynamics, salt and substrate transport and biofilm development in time was used to investigate the effects of cross-flow velocity and substrate availability on biofouling in reverse osmosis (RO)/nanofiltration (NF) feed channels. Simulations performed in channels with or without spacer filaments describe how higher liquid velocities lead to less overall biomass amount in the channel by increasing the shear stress. In all studied cases at constant feed flow rate, biomass accumulation in the channel reached a steady state. Replicate simulation runs prove that the stochastic biomass attachment model does not affect the stationary biomass level achieved and has only a slight influence on the dynamics of biomass accumulation. Biofilm removal strategies based on velocity variations are evaluated. Numerical results indicate that sudden velocity increase could lead to biomass sloughing, followed however by biomass re-growth when returning to initial operating conditions. Simulations show particularities of substrate availability in membrane devices used for water treatment, e.g., the accumulation of rejected substrates at the membrane surface due to concentration polarization. Interestingly, with an increased biofilm thickness, the overall substrate consumption rate dominates over accumulation due to substrate concentration polarization, eventually leading to decreased substrate concentrations in the biofilm compared to bulk liquid. © 2012 Elsevier B.V.

  4. Extension of CFD Codes Application to Two-Phase Flow Safety Problems - Phase 3

    International Nuclear Information System (INIS)

    Bestion, D.; Anglart, H.; Mahaffy, J.; Lucas, D.; Song, C.H.; Scheuerer, M.; Zigh, G.; Andreani, M.; Kasahara, F.; Heitsch, M.; Komen, E.; Moretti, F.; Morii, T.; Muehlbauer, P.; Smith, B.L.; Watanabe, T.

    2014-11-01

    The Writing Group 3 on the extension of CFD to two-phase flow safety problems was formed following recommendations made at the 'Exploratory Meeting of Experts to Define an Action Plan on the Application of Computational Fluid Dynamics (CFD) Codes to Nuclear Reactor Safety Problems' held in Aix-en-Provence, in May 2002. Extension of CFD codes to two-phase flow is significant potentiality for the improvement of safety investigations, by giving some access to smaller scale flow processes which were not explicitly described by present tools. Using such tools as part of a safety demonstration may bring a better understanding of physical situations, more confidence in the results, and an estimation of safety margins. The increasing computer performance allows a more extensive use of 3D modelling of two-phase Thermal hydraulics with finer nodalization. However, models are not as mature as in single phase flow and a lot of work has still to be done on the physical modelling and numerical schemes in such two-phase CFD tools. The Writing Group listed and classified the NRS problems where extension of CFD to two-phase flow may bring real benefit, and classified different modelling approaches in a first report (Bestion et al., 2006). First ideas were reported about the specification and analysis of needs in terms of validation and verification. It was then suggested to focus further activity on a limited number of NRS issues with a high priority and a reasonable chance to be successful in a reasonable period of time. The WG3-step 2 was decided with the following objectives: - selection of a limited number of NRS issues having a high priority and for which two-phase CFD has a reasonable chance to be successful in a reasonable period of time; - identification of the remaining gaps in the existing approaches using two-phase CFD for each selected NRS issue; - review of the existing data base for validation of two-phase CFD application to the selected NRS problems

  5. Cost-optimal power system extension under flow-based market coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Energiewirtschaftliches Inst.; Brown, Tom; Cherevatskiy, Stanislav; Troester, Eckehard [Energynautics GmbH, Langen (Germany)

    2013-05-15

    Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is first demonstrated on a simplified three-node model where it is found to be robust and convergent. It is then applied to the European power system in order to find its cost-optimal development under the prescription of strongly decreasing CO{sub 2} emissions until 2050.

  6. Determination of gallic acid with rhodanine by reverse flow injection analysis using simplex optimization.

    Science.gov (United States)

    Phakthong, Wilaiwan; Liawruangrath, Boonsom; Liawruangrath, Saisunee

    2014-12-01

    A reversed flow injection (rFI) system was designed and constructed for gallic acid determination. Gallic acid was determined based on the formation of chromogen between gallic acid and rhodanine, resulting in a colored product with a λmax at 520 nm. The optimum conditions for determining gallic acid were also investigated. Optimizations of the experimental conditions were carried out based on the so-call univariate method. The conditions obtained were 0.6% (w/v) rhodanine, 70% (v/v) ethanol, 0.9 mol L(-1) NaOH, 2.0 mL min(-1) flow rate, 75 μL injection loop and 600 cm mixing tubing length, respectively. Comparative optimizations of the experimental conditions were also carried out by multivariate or simplex optimization method. The conditions obtained were 1.2% (w/v) rhodanine, 70% (v/v) ethanol, 1.2 mol L(-1) NaOH, flow rate 2.5 mL min(-1), 75 μL injection loop and 600 cm mixing tubing length, respectively. It was found that the optimum conditions obtained by the former optimization method were mostly similar to those obtained by the latter method. The linear relationship between peak height and the concentration of gallic acid was obtained over the range of 0.1-35.0 mg L(-1) with the detection limit 0.081 mg L(-1). The relative standard deviations were found to be in the ranges 0.46-1.96% for 1, 10, 30 mg L(-1) of gallic acid (n=11). The method has the advantages of simplicity extremely high selectivity and high precision. The proposed method was successfully applied to the determination of gallic acid in longan samples without interferent effects from other common phenolic compounds that might be present in the longan samples collected in northern Thailand. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Effect of Temperature Reversion on Hot Ductility and Flow Stress-Strain Curves of C-Mn Continuously Cast Steels

    Science.gov (United States)

    Dong, Zhihua; Li, Wei; Long, Mujun; Gui, Lintao; Chen, Dengfu; Huang, Yunwei; Vitos, Levente

    2015-08-01

    The influence of temperature reversion in secondary cooling and its reversion rate on hot ductility and flow stress-strain curve of C-Mn steel has been investigated. Tensile specimens were cooled at various regimes. One cooling regime involved cooling at a constant rate of 100 °C min-1 to the test temperature, while the others involved temperature reversion processes at three different reversion rates before deformation. After hot tensile test, the evolution of mechanical properties of steel was analyzed at various scales by means of microstructure observation, ab initio prediction, and thermodynamic calculation. Results indicated that the temperature reversion in secondary cooling led to hot ductility trough occurring at higher temperature with greater depth. With increasing temperature reversion rate, the low temperature end of ductility trough extended toward lower temperature, leading to wider hot ductility trough with slightly reducing depth. Microstructure examinations indicated that the intergranular fracture related to the thin film-like ferrite and (Fe,Mn)S particles did not changed with varying cooling regimes; however, the Widmanstatten ferrite surrounding austenite grains resulted from the temperature reversion process seriously deteriorated the ductility. In addition, after the temperature reversion in secondary cooling, the peak stress on the flow curve slightly declined and the peak of strain to peak stress occurred at higher temperature. With increasing temperature reversion rate, the strain to peak stress slightly increased, while the peak stress showed little variation. The evolution of plastic modulus and strain to peak stress of austenite with varying temperature was in line with the theoretical prediction on Fe.

  8. Experimental investigation of the reverse heat transfer of R134a flow through non-adiabatic coiled capillary tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zareh, Masoud; Heidari, Mohammad Ghorbani [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-07-15

    This research represents an experimental investigation of the metastable flow and re-condensation phenomenon through non-adiabatic lateral helical capillary tubes and suction tube heat exchanger. The results show that mass flux ratio has a vital role: It affects metastable flow and also reverse heat transfer phenomenon through non-adiabatic helical capillary tube. Therefore, by increasing of the mass flux ratio, the rate of heat transfer between them decreases. In contrast to the strong rate condition of heat transfer between them, reverse heat transfer or re-condensation maybe happen. Moreover, experimental results show that for R134 flow with mass flux ratio more than 57.84, metastable flow exists in non-adiabatic capillary tube with 0.9144 mm inner diameter, 30 mm coil diameter, 6.18 m length, 4 mm inner diameter of compressor suction tube.

  9. Modelling of SOL flows and target asymmetries in JET field reversal experiments with EDGE2D code

    International Nuclear Information System (INIS)

    Chankin, A.; Coad, J.; Corrigan, G.

    1999-11-01

    The EDGE2D code with drifts can reproduce the main trends of target asymmetries observed in field reversal experiments. It also re-produces qualitatively the main feature of recent JET results obtained with double-sided reciprocating Langmuir probes introduced near the top of the torus: the reversal of parallel plasma flow with toroidal field reversal. The code results suggest that the major contributor to the observed target asymmetries is the co-current toroidal momentum generated inside the scrape-off layer (SOL) by j r xB forces due to the presence of large up-down pressure asymmetries. Contrary to previous expectations of the predominant role of ExB drifts in creating target asymmetries, ∇B and centrifugal drifts were found to be mainly responsible for both parallel flows and target asymmetries. (author)

  10. Operation of a catalytic reverse flow reactor for the purification of air contamined with volatile organic compounds

    NARCIS (Netherlands)

    van de Beld, L.; van de Beld, L.; Westerterp, K.R.

    1997-01-01

    Catalytic oxidation in a reverse flow reactor is an attractive process for the decontamination of air polluted with volatile organic compounds (VOCs). In this paper several aspects of operating this type of reactor for air purification under strongly varying conditions will be discussed. For a

  11. Experimental demonstration of the reverse flow catalytic membrane reactor concept for energy efficient syngas production. Part 2: Model development

    NARCIS (Netherlands)

    Smit, J.; Bekink, G.J.; Sint Annaland, van M.; Kuipers, J.A.M.

    2007-01-01

    In this contribution the technical feasibility of the reverse flow catalytic membrane reactor (RFCMR) concept with porous membranes for energy efficient syngas production is investigated. In earlier work an experimental proof of principle was already provided [Smit, J., Bekink, G.J., van Sint

  12. Feasibility study of a reverse flow catalytic membrane reactor with porous membranes for the production of syngas

    NARCIS (Netherlands)

    Smit, J.; van Sint Annaland, M.; Kuipers, J.A.M.

    2005-01-01

    In this paper a novel reverse flow catalytic membrane reactor (RFCMR) is proposed for the partial oxidation of CH4 to syngas. The feasibility of the RFCMR concept has been investigated for industrial conditions on basis of a simulation study employing a reactor model, which includes a detailed

  13. Reverse electron flow-induced ROS production is attenuated by activation of mitochondrial Ca2+-sensitive K+ channels

    NARCIS (Netherlands)

    Heinen, André; Aldakkak, Mohammed; Stowe, David F.; Rhodes, Samhita S.; Riess, Matthias L.; Varadarajan, Srinivasan G.; Camara, Amadou K. S.

    2007-01-01

    Mitochondria generate reactive oxygen species (ROS) dependent on substrate conditions, O(2) concentration, redox state, and activity of the mitochondrial complexes. It is well known that the FADH(2)-linked substrate succinate induces reverse electron flow to complex I of the electron transport chain

  14. Image based measurement techniques for aircraft propeller flow diagnostics : Propeller slipstream investigations at high-lift conditions and thrust reverse

    NARCIS (Netherlands)

    Roosenboom, E.W.M.

    2011-01-01

    The aim of the thesis is to measure the propeller slipstream properties (velocity and vorticity) and to assess the unsteady and instantaneous behavior of the propeller flow field at high disk loadings, zero thrust and thrust reverse using the image based measurement techniques. Along with its

  15. Stent revascularization restores cortical blood flow and reverses tissue hypoxia in atherosclerotic renal artery stenosis but fails to reverse inflammatory pathways or glomerular filtration rate.

    Science.gov (United States)

    Saad, Ahmed; Herrmann, Sandra M S; Crane, John; Glockner, James F; McKusick, Michael A; Misra, Sanjay; Eirin, Alfonso; Ebrahimi, Behzad; Lerman, Lilach O; Textor, Stephen C

    2013-08-01

    Atherosclerotic renal artery stenosis (ARAS) is known to reduce renal blood flow, glomerular filtration rate (GFR) and amplify kidney hypoxia, but the relationships between these factors and tubulointerstitial injury in the poststenotic kidney are poorly understood. The purpose of this study was to examine the effect of renal revascularization in ARAS on renal tissue hypoxia and renal injury. Inpatient studies were performed in patients with ARAS (n=17; >60% occlusion) before and 3 months after stent revascularization, or in patients with essential hypertension (n=32), during fixed Na(+) intake and angiotensin converting enzyme/angiotensin receptors blockers Rx. Single kidney cortical, medullary perfusion, and renal blood flow were measured using multidetector computed tomography, and GFR by iothalamate clearance. Tissue deoxyhemoglobin levels (R(2)*) were measured by blood oxygen level-dependent MRI at 3T, as was fractional kidney hypoxia (percentage of axial area with R(2)*>30/s). In addition, we measured renal vein levels of neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α. Pre-stent single kidney renal blood flow, perfusion, and GFR were reduced in the poststenotic kidney. Renal vein neutrophil gelatinase-associated lipocalin, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fractional hypoxia were higher in untreated ARAS than in essential hypertension. After stent revascularization, fractional hypoxia fell (Pblood flow, whereas GFR and neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α remained unchanged. These data demonstrate that despite reversal of renal hypoxia and partial restoration of renal blood flow after revascularization, inflammatory cytokines and injury biomarkers remained elevated and GFR failed to recover in ARAS. Restoration of vessel patency alone failed to reverse tubulointerstitial damage and partly

  16. Extensively Reversible Thermal Transformations of a Bistable, Fluorescence-Switchable Molecular Solid: Entry into Functional Molecular Phase-Change Materials.

    Science.gov (United States)

    Srujana, P; Radhakrishnan, T P

    2015-06-15

    Functional phase-change materials (PCMs) are conspicuously absent among molecular materials in which the various attributes of inorganic solids have been realized. While organic PCMs are primarily limited to thermal storage systems, the amorphous-crystalline transformation of materials like Ge-Sb-Te find use in advanced applications such as information storage. Reversible amorphous-crystalline transformations in molecular solids require a subtle balance between robust supramolecular assembly and flexible structural elements. We report novel diaminodicyanoquinodimethanes that achieve this transformation by interlinked helical assemblies coupled with conformationally flexible alkoxyalkyl chains. They exhibit highly reversible thermal transformations between bistable (crystalline/amorphous) forms, along with a prominent switching of the fluorescence emission energy and intensity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A Systematic Review of Outcomes and Complications of Primary Fingertip Reconstruction Using Reverse-Flow Homodigital Island Flaps.

    Science.gov (United States)

    Regmi, Subhash; Gu, Jia-xiang; Zhang, Nai-chen; Liu, Hong-jun

    2016-04-01

    Fingertip reconstruction using reverse-flow homodigital island flaps has been very popular over the years. However, the outcomes of reconstruction have not been clearly understood. In these circumstances, a systematic review of available literature is warranted. To assess the outcomes and complications of fingertip reconstruction using reverse-flow homodigital island flaps. To justify the usage of reverse-flow homodigital island flaps for fingertip reconstruction. A PubMed [MEDLINE] electronic database was searched (1985 to 15 April 2015). Retrospective case series that met the following criteria were included: (1) Study reported primary data; (2) Study included at least five cases of fingertip defects treated using reverse-flow homodigital island flaps; (3) Study reported outcomes and complications of fingertip reconstruction, either primary or delayed, using reverse-flow homodigital island flaps; (4) The study presented at least one of the following functional outcomes: Static two-point discrimination, return-to-work time, range of motion of distal interphalangeal joints; (5) The study presented at least one complication. Two review authors independently assessed search results, and two other review authors analyzed the data and resolved disagreements. The following endpoints were analyzed: survival rate of the flap, sensibility, and functional outcomes and complications. Eight studies were included in this review. The included studies were published between 1995 and 2014, and a total of 207 patients with 230 fingertip defects were reported. The overall survival rate of the flap was 98 % (including partial survival). The mean static two-point discrimination (2PD) was 7.2 mm. The average range of motion of the DIP joint was 63°. The average return-to-work time was 7 weeks after injury. On average, 2 % of the patient had complete flap necrosis, 5 % had partial flap necrosis, 4 % developed venous congestion, 4 % developed flexion contracture, and 12 % experienced

  18. Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.

    Science.gov (United States)

    Hayes, J D; Malik, A

    2001-03-01

    Sol-gel chemistry was successfully used for the fabrication of open tubular columns with surface-bonded octadecylsilane (ODS) stationary-phase coating for capillary electrochromatography (OT-CEC). Following column preparations, a series of experiments were performed to investigate the performance of the sol-gel coated ODS columns in OT-CEC. The incorporation of N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride as one of the sol-gel precursors played an important role in the electrochromatographic performance of the prepared columns. This chemical reagent possesses a chromatographically favorable, bonded ODS moiety, in conjunction with three methoxy groups allowing for sol-gel reactivity. In addition, a positively charged nitrogen atom is present in the molecular structure of this reagent and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the columns during CEC operation. Comparative studies involving the EOF within such sol-gel ODS coated and uncoated capillaries were performed using acetonitrile and methanol as the organic modifiers in the mobile phase. The use of a deactivating reagent, phenyldimethylsilane, in the sol-gel solution was evaluated. Efficiency values of over 400,000 theoretical plates per meter were achieved in CEC on a 64 cm x 25 microm i.d. sol-gel ODS open tubular column. Test mixtures of polycyclic aromatic hydrocarbons, benzene derivatives, and aromatic aldehydes and ketones were used to evaluate the CEC performances of both nondeactivated and deactivated open tubular sol-gel columns. The effects of mobile-phase organic modifier contents and pH on EOF in such columns were evaluated. The prepared sol-gel ODS columns are characterized by switchable electroosmotic flow. A pH value of approximately 8.5 was found correspond to the isoelectric point for the prepared sol-gel ODS coatings.

  19. Reverse flow injection spectrophotometric determination of thiram and nabam fungicides in natural water samples

    International Nuclear Information System (INIS)

    Asghar, M.; Yaqoob, M.; Nabi, A.

    2014-01-01

    A reverse flow injection (rFI) spectrophotometric method is reported for determination of thiram and nabam fungicides in natural water samples. The method is based on the reduction of iron(III) in the presence of thiram/nabam in acidic medium at 60 degree C and formation of iron(II)-ferricyanide complex was measured at 790 nm. The limits of detection (3s blank) were 0.01 and 0.05 micro g mL1 for thiram and nabam respectively with a sample throughput of 60 h1. Calibration graphs were linear over the range of 0.02 - 8.0 micro g mL1 (R2 = 0.9999, n = 8) and 0.1 - 30 micro g mL1 (R2 = 0.9982, n = 10) for thiram and nabam with relative standard deviations (RSDs; n = 3) in the range of 0.8 - 1.6% respectively. Experimental parameters and potential interferences were examined. Thiram and nabam were determined in natural water samples using solid-phase extraction (SPE) procedure and recoveries were in the range of 93+-3 - 105+-2% and 87+-4 - 102+-3% respectively. The results obtained were not significantly different compared with a HPLC method. (author)

  20. A Singular Perturbation Problem for Steady State Conversion of Methane Oxidation in Reverse Flow Reactor

    Directory of Open Access Journals (Sweden)

    Aang Nuryaman

    2012-11-01

    Full Text Available The governing equations describing the methane oxidation process in reverse flow reactor are given by a set of convective-diffusion equations with a nonlinear reaction term, where temperature and methane conversion are dependent variables. In this study, the process is assumed to be one-dimensional pseudo homogeneous model and takes place with a certain reaction rate in which the whole process of reactor is still workable. Thus, the reaction rate can proceed at a fixed temperature. Under this condition, we restrict ourselves to solve the equations for the conversion only. From the available data, it turns out that the ratio of the diffusion term to the reaction term is small. Hence, this ratio is considered as small parameter in our model and this leads to a singular perturbation problem. In the vicinity of small parameter in front of higher order term, the numerical difficulties will be found. Here, we present an analytical solution by means of matched asymptotic expansions. Result shows that, up to and including the first order of approximation, the solution is in agreement with the exact and numerical solutions of the boundary value problem.

  1. Reversible chemical delithiation/lithiation of LiFePO4: towards a redox flow lithium-ion battery.

    Science.gov (United States)

    Huang, Qizhao; Li, Hong; Grätzel, Michael; Wang, Qing

    2013-02-14

    Reversible chemical delithiation/lithiation of LiFePO(4) was successfully demonstrated using ferrocene derivatives, based on which a novel energy storage system--the redox flow lithium-ion battery (RFLB), was devised by integrating the operation flexibility of a redox flow battery and high energy density of a lithium-ion battery. Distinct from the recent semi-solid lithium rechargeable flow battery, the energy storage materials of RFLB stored in separate energy tanks remain stationary upon operation, giving us a fresh perspective on building large-scale energy storage systems with higher energy density and improved safety.

  2. Stability management of high speed axial flow compressor stage through axial extensions of bend skewed casing treatment

    Directory of Open Access Journals (Sweden)

    DilipkumarBhanudasji Alone

    2016-09-01

    Full Text Available This paper presents the experimental results to understand the performance of moderately loaded high speed single stage transonic axial flow compressor subjected to various configurations of axial extensions of bend skewed casing treatment with moderate porosity. The bend skewed casing treatment of 33% porosity was coupled with rectangular plenum chamber of depth equal to the slots depth. The five axial extensions of 20%, 40%, 60%, 80% and 100% were used for the experimental evaluations of compressor performance. The main objective was to identify the optimum extension of the casing treatment with reference to rotor leading edge which results in maximum stall margin improvements with minimum loss in the stage efficiency. At each axial extension the compressor performance is distinctive. The improvement in the stall margin was very significant at some axial extensions with 4%–5% penalty in the stage efficiency. The compressors stage shows recovery in terms of efficiency at lower axial extensions of 20% and 40% with increase in the peak stage efficiency. Measurements of flow parameters showed the typical behaviors at near stall flow conditions. Hot wire sensor was placed at the rotor upstream in the tip region to capture the oscillations in the inlet axial and tangential velocities at stall conditions. In the absence of casing treatment the compressor exhibit abrupt stall with very high oscillations in the inlet axial and tangential velocity of the flow. The extents of oscillations reduce with bend skewed casing treatment. Few measurements were also performed in the plenum chamber and salient results are presented in this paper.

  3. Pulmonary Venous Diastolic Flow Reversal and Flash Pulmonary Edema During Management of Ongoing Myocardial Ischemia with Intraaortic Balloon Pump.

    Science.gov (United States)

    Murray, Davoy; Peng, Yong G

    2015-10-15

    A 65-year-old man was admitted for acute coronary syndrome with depressed left ventricular function and moderate aortic regurgitation. He was managed with an intraaortic balloon pump for circulatory support before coronary artery bypass grafting and subsequently developed flash pulmonary edema with an associated rare finding of diastolic pulmonary venous flow reversal. In this report, we provide a review of intraaortic balloon pump use in current clinical practice and elaborate on the pathophysiology of an uncommon pulmonary venous flow pattern found in our patient.

  4. Numerical investigation on the energetic performances of conventional and pellet aftertreatment systems in flow-through and reverse-flow designs

    Directory of Open Access Journals (Sweden)

    Morrone Pietropaolo

    2011-01-01

    Full Text Available The aim of the paper is the analysis of the energetic performances of structured and pelletized aftertreatment systems in flow-through and reverse-flow designs (passive and active flow control respectively for diesel internal combustion engines. To this purpose, the influence of the engine operating conditions on the system performances has been investigated adopting a one-dimensional time-dependent model. Specifically, the thermal behaviour and the fuel saving capability of several arrangements have been characterized. The analysis has shown that the active emission control system with pelletized design guarantees higher heat retention capability. Furthermore, the numerical model has revealed the significant influence of the solid and exhaust gas temperature on the energy efficiency of the aftertreatment systems and the large effect of exhaust mass flow rate and unburned hydrocarbons concentration.

  5. Backarc extension, detachments and granitoids in the Aegean, their relations to slab tear and asthenospheric flow

    Science.gov (United States)

    Jolivet, Laurent; Menant, Armel; Rabillard, Aurélien; Arbaret, Laurent; Augier, Romain; Gumiaux, Charles

    2013-04-01

    The Cycladic granitoids (Ikaria, Mykonos, Naxos, Kos, Lavrion, Serifos, Tinos) intruded the Aegean crust during a rather short period (17-10 Ma) compared to the much longer Oligo-Miocene crustal thinning phase (35 Ma to the Present). Their geochemical characteristics show that their sources have changed through time and space, with a progressive decreasing component of continental crust contamination with time and from east to west. They all interacted with large-scale detachments, namely the North Cycladic Detachment System (NCDS) in the north and the West Cycladic Detachment System (WCDS) in the south. In Mykonos, Naxos, Serifos and Ikaria the plutons are also associated with a high-temperature metamorphic dome of Miocene age. Their intrusion period roughly covers the same time window as the fast clockwise rotation of the western Aegean evidenced by paleomagnetic measurements and they are contemporaneous with a surge of alkaline volcanism in the eastern Aegean that can be related to a slab tear imaged below western Anatolia. The continental crust component in the Middle Miocene Cycladic plutons is not found in the early Miocene plutons of the northern Aegean, like in Kavala and Vrondou. They thus probably record a quite sudden thermal event in the Cyclades that led to the partial melting of the extending deep crust. We propose a model involving slab tear starting at ~17 Ma, fast retreat of the slab west of the tear and southwestward influx of hot asthenospheric material below the Aegean crust, leading to melting of the lower crust. Partial melting of the whole lower crust above the hot asthenospheric flow could explain the flat Moho observed below the Cyclades. The close proximity of plutons with the detachments suggests that their ascent toward the upper crust is favoured by the extreme extension at work there. The first granitoids in the region of the tear (Ikaria) are the richest in crustal component and this component decreases while the crust thins more and

  6. Flame stabilization and mixing characteristics in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Bobba, Mohan K.

    A novel combustor design, referred to as the Stagnation Point Reverse-Flow (SPRF) combustor, was recently developed that is able to operate stably at very lean fuel-air mixtures and with low NOx emissions even when the fuel and air are not premixed before entering the combustor. The primary objective of this work is to elucidate the underlying physics behind the excellent stability and emissions performance of the SPRF combustor. The approach is to experimentally characterize velocities, species mixing, heat release and flame structure in an atmospheric pressure SPRF combustor with the help of various optical diagnostic techniques: OH PLIF, chemiluminescence imaging, PIV and Spontaneous Raman Scattering. Results indicate that the combustor is primarily stabilized in a region downstream of the injector that is characterized by low average velocities and high turbulence levels; this is also the region where most of the heat release occurs. High turbulence levels in the shear layer lead to increased product entrainment levels, elevating the reaction rates and thereby enhancing the combustor stability. The effect of product entrainment on chemical timescales and the flame structure is illustrated with simple reactor models. Although reactants are found to burn in a highly preheated (1300 K) and turbulent environment due to mixing with hot product gases, the residence times are sufficiently long compared to the ignition timescales such that the reactants do not autoignite. Turbulent flame structure analysis indicates that the flame is primarily in the thin reaction zones regime throughout the combustor, and it tends to become more flamelet like with increasing distance from the injector. Fuel-air mixing measurements in case of non-premixed operation indicate that the fuel is shielded from hot products until it is fully mixed with air, providing nearly premixed performance without the safety issues associated with premixing. The reduction in NOx emissions in the SPRF

  7. Analysis of the interaction between a submerged jet and a receiver-diffuser in a reverse-flow diverter. Consolidated Fuel Reprocessing Program

    International Nuclear Information System (INIS)

    Smith, G.V.; Counce, R.M.

    1983-01-01

    Two mathematical models of the interaction between a submerged jet emanating from the nozzle of a reverse flow diverter (RFD) and a receiver-diffuser of a venturi-like reverse flow diverter are presented and compared with experimental data. Both models predict the output characteristics fairly accurately, although the experimentally measured flow is observed to saturate at higher values of jet dynamic pressure and at lower values of output load impedances. An analysis based on the inviscid flow model indicates cavitation as the likely cause of the flow saturation

  8. An extensive cocktail approach for rapid risk assessment of in vitro CYP450 direct reversible inhibition by xenobiotic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Spaggiari, Dany, E-mail: dany.spaggiari@unige.ch [School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d' Yvoy 20, 1211 Geneva 4 (Switzerland); Daali, Youssef, E-mail: youssef.daali@hcuge.ch [Clinical Pharmacology and Toxicology Service, Geneva University Hospitals, Rue Gabrielle Perret-Gentil, 1211 Genève 14 (Switzerland); Rudaz, Serge, E-mail: serge.rudaz@unige.ch [School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Boulevard d' Yvoy 20, 1211 Geneva 4 (Switzerland); Swiss Centre for Applied Human Toxicology, University of Geneva, Boulevard d' Yvoy 20, 1211 Geneva 4 (Switzerland)

    2016-07-01

    Acute exposure to environmental factors strongly affects the metabolic activity of cytochrome P450 (P450). As a consequence, the risk of interaction could be increased, modifying the clinical outcomes of a medication. Because toxic agents cannot be administered to humans for ethical reasons, in vitro approaches are therefore essential to evaluate their impact on P450 activities. In this work, an extensive cocktail mixture was developed and validated for in vitro P450 inhibition studies using human liver microsomes (HLM). The cocktail comprised eleven P450-specific probe substrates to simultaneously assess the activities of the following isoforms: 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2 and subfamily 3A. The high selectivity and sensitivity of the developed UHPLC-MS/MS method were critical for the success of this methodology, whose main advantages are: (i) the use of eleven probe substrates with minimized interactions, (ii) a low HLM concentration, (iii) fast incubation (5 min) and (iv) the use of metabolic ratios as microsomal P450 activities markers. This cocktail approach was successfully validated by comparing the obtained IC{sub 50} values for model inhibitors with those generated with the conventional single probe methods. Accordingly, reliable inhibition values could be generated 10-fold faster using a 10-fold smaller amount of HLM compared to individual assays. This approach was applied to assess the P450 inhibition potential of widespread insecticides, namely, chlorpyrifos, fenitrothion, methylparathion and profenofos. In all cases, P450 2B6 was the most affected with IC{sub 50} values in the nanomolar range. For the first time, mixtures of these four insecticides incubated at low concentrations showed a cumulative inhibitory in vitro effect on P450 2B6. - Highlights: • Ten P450 isoforms activities assessed simultaneously with only one incubation. • P450 activity levels measured using the metabolic ratio approach. • IC{sub 50} values generated 10

  9. An extensive cocktail approach for rapid risk assessment of in vitro CYP450 direct reversible inhibition by xenobiotic exposure

    International Nuclear Information System (INIS)

    Spaggiari, Dany; Daali, Youssef; Rudaz, Serge

    2016-01-01

    Acute exposure to environmental factors strongly affects the metabolic activity of cytochrome P450 (P450). As a consequence, the risk of interaction could be increased, modifying the clinical outcomes of a medication. Because toxic agents cannot be administered to humans for ethical reasons, in vitro approaches are therefore essential to evaluate their impact on P450 activities. In this work, an extensive cocktail mixture was developed and validated for in vitro P450 inhibition studies using human liver microsomes (HLM). The cocktail comprised eleven P450-specific probe substrates to simultaneously assess the activities of the following isoforms: 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2 and subfamily 3A. The high selectivity and sensitivity of the developed UHPLC-MS/MS method were critical for the success of this methodology, whose main advantages are: (i) the use of eleven probe substrates with minimized interactions, (ii) a low HLM concentration, (iii) fast incubation (5 min) and (iv) the use of metabolic ratios as microsomal P450 activities markers. This cocktail approach was successfully validated by comparing the obtained IC 50 values for model inhibitors with those generated with the conventional single probe methods. Accordingly, reliable inhibition values could be generated 10-fold faster using a 10-fold smaller amount of HLM compared to individual assays. This approach was applied to assess the P450 inhibition potential of widespread insecticides, namely, chlorpyrifos, fenitrothion, methylparathion and profenofos. In all cases, P450 2B6 was the most affected with IC 50 values in the nanomolar range. For the first time, mixtures of these four insecticides incubated at low concentrations showed a cumulative inhibitory in vitro effect on P450 2B6. - Highlights: • Ten P450 isoforms activities assessed simultaneously with only one incubation. • P450 activity levels measured using the metabolic ratio approach. • IC 50 values generated 10-fold faster

  10. Control of Flow Separation on a Turbine Blade by Utilizing Tail Extensions

    National Research Council Canada - National Science Library

    Murawski, C

    1999-01-01

    .... The axial chord of the blades was varied using tail extenders from 0% to 15% beyond design. The effects of Reynolds number on a low pressure turbine cascade blade with tail extensions was investigated...

  11. The significance of reverse flow in ductus venosus between sixteen and twenty weeks’ gestation

    Directory of Open Access Journals (Sweden)

    Gökhan Karakoç

    2017-03-01

    Full Text Available Objective: To evaluate the correlation between reversed a-wave in ductus venosus at 16-20 weeks’ gestation and trisomy 21 and adverse perinatal outcomes. Materials and Methods: Our study included 174 pregnant women who were under follow-up at a tertiary center between May and September 2010. Ductus venosus Doppler (DVD measurements were obtained throughout the 6-month period from women who underwent amniocentesis procedures due to increased risk for trisomy 21 in terms of first or second trimester screening test results. These women were followed up for enrollment of subsequent data about perinatal outcomes. Results: In 13 of 174 cases, Doppler studies indicated a reversed a-wave in the ductus venosus. Of these fetuses, 3 were diagnosed as having trisomy 21 after amniocentesis, which related to 60% (3 of 5 fetuses of all fetuses with trisomy 21. The pregnant women with reversed a-wave in DVD also had an increased rate of preeclampsia (15% and gestational diabetes mellitus (GDM (23% in late pregnancy. Conclusion: Reversed a-wave in ductus venosus between 16-20 weeks’ gestation is associated with increased risk of trisomy 21, preeclampsia, and GDM. If further prospective studies confirm its utility, DVD interrogation for trisomy 21 may be extended until 20 weeks’ gestation.

  12. CO2 saturated water as two-phase flow for fouling control in reverse electrodialysis

    NARCIS (Netherlands)

    Moreno, J.; de Hart, N.; Saakes, M.; Nijmeijer, K.

    2017-01-01

    When natural feed waters are used in the operation of a reverse electrodialysis (RED) stack, severe fouling on the ion exchange membranes and spacers occurs. Fouling of the RED stack has a strong influence on the gross power density output; which can decrease up to 50%. Moreover, an increase in the

  13. Flow reversal in combined laminar mixed convection heat and mass transfer with phase change in a vertical channel

    International Nuclear Information System (INIS)

    Oulaid, Othmane; Benhamou, Brahim; Galanis, Nicolas

    2010-01-01

    This paper, deals with a numerical study of the effects of buoyancy forces on an upward, steady state, laminar flow of humid air in a vertical parallel-plate channel. The plates are wetted by a thin liquid water film and maintained at a constant temperature which is lower than that of the air entering the channel. A 2D fully elliptical model, associated with the Boussinesq assumption, is used to take into account axial diffusion. The solution of this mathematical model is based on the finite volume method and the velocity-pressure coupling is handled by the SIMPLER algorithm. Numerical results show that buoyancy forces have a significant effect on the hydrodynamic, thermal and mass fraction fields. Additionally, these forces induce flow reversal for high air temperatures and mass fractions at the channel entrance. It is established that heat transfer associated with phase change is, sometimes, more significant than sensible heat transfer. Furthermore, this importance depends on the mass fraction gradient. The conditions for the existence of flow reversal are presented in charts and analytical expressions specifying the critical thermal Grashof number as a function of the Reynolds number for different values of the solutal Grashof number and different aspect ratios of the channel.

  14. Integration of continuous-flow sampling with microchip electrophoresis using poly(dimethylsiloxane)-based valves in a reversibly sealed device.

    Science.gov (United States)

    Li, Michelle W; Martin, R Scott

    2007-07-01

    Here we describe a reversibly sealed microchip device that incorporates poly(dimethylsiloxane) (PDMS)-based valves for the rapid injection of analytes from a continuously flowing stream into a channel network for analysis with microchip electrophoresis. The microchip was reversibly sealed to a PDMS-coated glass substrate and microbore tubing was used for the introduction of gas and fluids to the microchip device. Two pneumatic valves were incorporated into the design and actuated on the order of hundreds of milliseconds, allowing analyte from a continuously flowing sampling stream to be injected into an electrophoresis separation channel. The device was characterized in terms of the valve actuation time and pushback voltage. It was also found that the addition of sodium dodecyl sulfate (SDS) to the buffer system greatly increased the reproducibility of the injection scheme and enabled the analysis of amino acids derivatized with naphthalene-2,3-dicarboxaldehyde/cyanide. Results from continuous injections of a 0.39 nL fluorescein plug into the optimized system showed that the injection process was reproducible (RSD of 0.7%, n = 10). Studies also showed that the device was capable of monitoring off-chip changes in concentration with a device lag time of 90 s. Finally, the ability of the device to rapidly monitor on-chip concentration changes was demonstrated by continually sampling from an analyte plug that was derivatized upstream from the electrophoresis/continuous flow interface. A reversibly sealed device of this type will be useful for the continuous monitoring and analysis of processes that occur either off-chip (such as microdialysis sampling) or on-chip from other integrated functions.

  15. Creep measurements confirm steady flow after stress maximum in extension of branched polymer melts

    DEFF Research Database (Denmark)

    Javier Alvarez, Nicolas; Román Marín, José Manuel; Huang, Qian

    2013-01-01

    We provide conclusive evidence of nonmonotonic mechanical behavior in the extension of long-chain branched polymer melts. While nonmonotonic behavior is known to occur for solids, for the case of polymeric melts, this phenomenon is in direct contrast with current theoretical models. We rule out t...

  16. Index-Based Assessment of Voltage Rise and Reverse Power Flow Phenomena in a Distribution Feeder Under High PV Penetration

    DEFF Research Database (Denmark)

    Hasheminamin, Maryam; Agelidis, Vassilios G.; Salehi, Vahid

    2015-01-01

    -based methodology for assessing the impact of high solar PV generation, considering the reverse power flow and voltage rise phenomena. Indices are defined that link these two phenomena and their impact on the voltage profile across the feeder. This assessment relies on detailed modeling of the network and the solar......The proliferation of photovoltaic (PV) generation in low- and medium-voltage distribution networks is expected to continue. Qualified studies can quantify adverse impacts of high PV penetration on distribution networks and assist utilities in decision making. This paper proposes an index...

  17. Synergistic effects of the safety factor and shear flows on development of internal transport barriers in reversed shear plasmas

    International Nuclear Information System (INIS)

    Wang, A.K.; Dong, J.Q.; Qu, W.X.; Qiu, X.M.

    2002-01-01

    A new suppression mechanism of turbulent transport, characteristic of the synergism between safety factor and shear flows, is proposed to explain the internal transport barriers (ITBs) observed in neutral-beam-heated tokamak discharges with reversed magnetic shear. It is shown that the evolution of turbulent transport with the strength of the suppression mechanism reproduces the basic features of the formation and development of ITBs observed in experiments. In addition, the present analyses predict the possibility of global ion and electron heat transport barriers

  18. Positron emission tomography in the newborn: extensive impairment of regional cerebral blood flow with intraventricular hemorrhage and hemorrhagic intracerebral involvement

    International Nuclear Information System (INIS)

    Volpe, J.J.; Herscovitch, P.; Perlman, J.M.; Raichle, M.E.

    1983-01-01

    Positron emission tomography (PET) now provides the capability of measuring regional cerebral blood flow with high resolution and little risk. In this study, we utilized PET in six premature infants (920 to 1,200 g) with major intraventricular hemorrhage and hemorrhagic intracerebral involvement to measure regional cerebral blood flow during the acute period (5 to 17 days of age). Cerebral blood flow was determined after intravenous injection of H 2 O, labeled with the positron-emitting isotope, 15 O. Findings were similar and dramatic in all six infants. In the area of hemorrhagic intracerebral involvement, little or no cerebral blood flow was detected. However, in addition, surprisingly, a marked two- to fourfold reduction in cerebral blood flow was observed throughout the affected hemisphere, well posterior and lateral to the intracerebral hematoma, including cerebral white matter and, to a lesser extent, frontal, temporal, and parietal cortex. In the one infant studied a second time, ie, at 3 months of age, the extent and severity of the decreased cerebral blood flows in the affected hemisphere were similar to those observed on the study during the neonatal period. At the three autopsies, the affected left hemisphere showed extensive infarction, corroborating the PET scans. These observations, the first demonstration of the use of PET in the determination of regional cerebral blood flow in the newborn, show marked impairments in regional cerebral blood flow in the hemisphere containing an apparently restricted intracerebral hematoma, indicating that the hemorrhagic intracerebral involvement is only a component of a much larger lesion, ischemic in basic nature, ie, an infarction. This large ischemic lesion explains the poor neurologic outcome in infants with intraventricular hemorrhage and hemorrhagic intracerebral involvement

  19. Flow and solute transport in backfilled tunnel and collapsed backfill - possible extension of Comp32

    International Nuclear Information System (INIS)

    Neretnieks, Ivars

    2006-09-01

    In the Swedish deep geological final repository for spent fuel the tunnels will be filled with a backfill with low permeability. However, some flow may take place in the backfill. Nuclides released from a leaking canister could diffuse up to the flowing water in the backfill and be transported downstream in the tunnel. At an intersection of the tunnel with a fracture zone the contaminated water might flow out into the zone.This report addresses the transport mechanisms and rate of transport from a leaking canister up through the buffer and backfill in the deposition hole, further into the backfill in the tunnel and the transport along the tunnel. Spreading by diffusion in the buffer and backfill as well as retardation of sorbing nuclides is accounted for.The transport mechanisms and rates of transport are described and some simple models with analytical solutions are used to quantify the processes. These simple solutions are used to gain insights into when different transport mechanisms are important. The simple solutions are used to simulate a base case example where a non-sorbing nuclide (iodide) and a sorbing nuclide (radium) move in the backfill by diffusion and by advective flow. The simple sample calculations show that it would take thousands of years for iodide to move 20 m along the tunnel and that a release pulse would spread out considerably over time. The sorbing nuclide 226 Ra with a half life of 1,600 years would be strongly retarded by sorption and would decay to insignificance during its migration along the tunnel. The consequences of a collapse of backfill leaving a channel above the backfill is also studied by a simple analytical model that accounts for water flowing in the collapsed part of the backfill at the ceiling of the tunnel. A nuclide that diffuses up to the flowing channel will flow with the ('rapidly' flowing) water but will be retarded by diffusion down into the backfill again. This down diffusion retards the nuclide migration

  20. Flow and solute transport in backfilled tunnel and collapsed backfill - possible extension of Comp32

    Energy Technology Data Exchange (ETDEWEB)

    Neretnieks, Ivars [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2006-09-15

    In the Swedish deep geological final repository for spent fuel the tunnels will be filled with a backfill with low permeability. However, some flow may take place in the backfill. Nuclides released from a leaking canister could diffuse up to the flowing water in the backfill and be transported downstream in the tunnel. At an intersection of the tunnel with a fracture zone the contaminated water might flow out into the zone.This report addresses the transport mechanisms and rate of transport from a leaking canister up through the buffer and backfill in the deposition hole, further into the backfill in the tunnel and the transport along the tunnel. Spreading by diffusion in the buffer and backfill as well as retardation of sorbing nuclides is accounted for.The transport mechanisms and rates of transport are described and some simple models with analytical solutions are used to quantify the processes. These simple solutions are used to gain insights into when different transport mechanisms are important. The simple solutions are used to simulate a base case example where a non-sorbing nuclide (iodide) and a sorbing nuclide (radium) move in the backfill by diffusion and by advective flow. The simple sample calculations show that it would take thousands of years for iodide to move 20 m along the tunnel and that a release pulse would spread out considerably over time. The sorbing nuclide {sup 226}Ra with a half life of 1,600 years would be strongly retarded by sorption and would decay to insignificance during its migration along the tunnel. The consequences of a collapse of backfill leaving a channel above the backfill is also studied by a simple analytical model that accounts for water flowing in the collapsed part of the backfill at the ceiling of the tunnel. A nuclide that diffuses up to the flowing channel will flow with the ('rapidly' flowing) water but will be retarded by diffusion down into the backfill again. This down diffusion retards the nuclide

  1. Extension of the Gladstone-Dale equation for flame flow field diagnosis by optical computerized tomography

    International Nuclear Information System (INIS)

    Chen Yunyun; Li Zhenhua; Song Yang; He Anzhi

    2009-01-01

    An extended model of the original Gladstone-Dale (G-D) equation is proposed for optical computerized tomography (OCT) diagnosis of flame flow fields. For the purpose of verifying the newly established model, propane combustion is used as a practical example for experiment, and moire deflection tomography is introduced with the probe wavelength 808 nm. The results indicate that the temperature based on the extended model is more accurate than that based on the original G-D equation. In a word, the extended model can be suitable for all kinds of flame flow fields whatever the components, temperature, and ionization are.

  2. Extension of CE/SE method to non-equilibrium dissociating flows

    KAUST Repository

    Wen, C.Y.

    2017-12-08

    In this study, the hypersonic non-equilibrium flows over rounded nose geometries are numerically investigated by a robust conservation element and solution element (CE/SE) code, which is based on hybrid meshes consisting of triangular and quadrilateral elements. The dissociating and recombination chemical reactions as well as the vibrational energy relaxation are taken into account. The stiff source terms are solved by an implicit trapezoidal method of integration. Comparison with laboratory and numerical cases are provided to demonstrate the accuracy and reliability of the present CE/SE code in simulating hypersonic non-equilibrium flows.

  3. Spatial heterogeneity of biofouling under different cross-flow velocities in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia; Staal, M.; Bucs, Szilard; Van Loosdrecht, M.C.M.; Vrouwenvelder, Johannes S.

    2016-01-01

    the spatial heterogeneity of biofilm development over the membrane fouling simulator (MFS) length (inlet and outlet part) at three different cross-flow velocities (0.08, 0.12 and 0.16 m/s). The MFS contained sheets of membrane and feed spacer and simulatedComparison of the inlet and outlet position of the MFS showed a more (i) heterogeneous biofilm distribution and a (ii) higher biological activity at the inlet side (first 2.5 cm) for all cross-flow velocities. The lowest cross-flow velocity had

  4. Cross flow filtration for radwaste applications reverse osmosis demonstration case studies

    International Nuclear Information System (INIS)

    Malkmus, D.

    1995-01-01

    Today's radwaste economic and regulatory scenarios signify the importance in the improvement of operational practices to reduce generator liabilities. This action is largely due to the rising cost dealing with burial sites and the imposed waste volume restriction. To control the economical burdens associated with waste burial and to comply with stricter environmental regulations, NPP's are attempting to modify their radwaste system(s) design and operating philosophy by placing a major emphasis on waste volume reduction and processing techniques. The utilization of reverse osmosis technology as a means for treatment of process and wastewater streams in the nuclear power industry has been investigated for many years. This paper will outline reverse osmosis theory and highlight performance data for process and waste stream purification applications. Case studies performed at 5 nuclear plants have been outlined. The demonstrations were performed on a widely variety of process stream for both a PWR and BWR application. The data provided by the pilot systems, the equipment design, and the economical impact a reverse osmosis unit will have on producing treated (high purity) are as follows

  5. Effect of flow velocity, substrate concentration and hydraulic cleaning on biofouling of reverse osmosis feed channels

    KAUST Repository

    Radu, Andrea I.; Vrouwenvelder, Johannes S.; van Loosdrecht, Mark C.M.; Picioreanu, Cristian

    2012-01-01

    )/nanofiltration (NF) feed channels. Simulations performed in channels with or without spacer filaments describe how higher liquid velocities lead to less overall biomass amount in the channel by increasing the shear stress. In all studied cases at constant feed flow

  6. Dynamic alteration of regional cerebral blood flow during carotid compression and proof of reversibility

    International Nuclear Information System (INIS)

    Asahi, Kouichi; Hori, M; Hamasaki, N; Sato, S; Nakanishi, H; Kuwatsuru, R; Sasai, K; Aoki, S

    2012-01-01

    It is difficult to non-invasively visualize changes in regional cerebral blood flow caused by manual compression of the carotid artery. To visualize dynamic changes in regional cerebral blood flow during and after manual compression of the carotid artery. Two healthy volunteers were recruited. Anatomic features and flow directions in the circle of Willis were evaluated with time-of-flight magnetic resonance angiography (MRA) and two-dimensional phase-contrast (2DPC) MRA, respectively. Regional cerebral blood flow was visualized with territorial arterial spin-labeling magnetic resonance imaging (TASL-MRI). TASL-MRI and 2DPC-MRA were performed in three states: at rest, during manual compression of the right carotid artery, and after decompression. In one volunteer, time-space labeling inversion pulse (Time-SLIP) MRA was performed to confirm collateral flow. During manual carotid compression, in one volunteer, the right thalamus changed to be fed only by the vertebrobasilar system, and the right basal ganglia changed to be fed by the left internal carotid artery. In the other volunteer, the right basal ganglia changed to be fed by the vertebrobasilar system. 2DPC-MRA showed that the flow direction changed in the right A1 segment of the anterior cerebral artery and the right posterior communicating artery. Perfusion patterns and flow directions recovered after decompression. Time-SLIP MRA showed pial vessels and dural collateral circulation when the right carotid artery was manually compressed. Use of TASL-MRI and 2DPC-MRA was successful for non-invasive visualization of the dynamic changes in regional cerebral blood flow during and after manual carotid compression

  7. Arc-parallel extension and fluid flow in an ancient accretionary wedge: The San Juan Islands, Washington

    Science.gov (United States)

    Schermer, Elizabeth R.; Gillaspy, J.R.; Lamb, R.

    2007-01-01

    Structural analysis of the Lopez Structural Complex, a major Late Cretaceous terrane-bounding fault zone in the San Juan thrust system, reveals a sequence of events that provides insight into accretionary wedge mechanics and regional tectonics. After formation of regional ductile flattening and shear-related fabrics, the area was crosscut by brittle structures including: (1) southwest-vergent thrusts, (2) extension veins and normal faults related to northwest-southeast extension, and (3) conjugate strike-slip structures that record northwest-southeast extension and northeast-southwest shortening. Aragonite-bearing veins are associated with thrust and normal faults, but only rarely with strike-slip faults. High-pressure, low-temperature (HP-LT) minerals constrain the conditions for brittle deformation to ???20 km and formed in an accretionary prism during active subduction, which suggests that these brittle structures record internal wedge deformation at depth and early during uplift of the San Juan nappes. The structures are consistent with orogen-normal shortening and vertical thickening followed by vertical thinning and along-strike extension. The kinematic evolution may be related initially to changes in wedge strength, followed by response to overthickening of the wedge in an unbuttressed, obliquely convergent setting. The change in vein mineralogy indicates that exhumation occurred prior to the strike-slip event. The pressure and temperature conditions and spatial and temporal extent of small faults associated with fluid flow suggest a link between these structures and the silent earthquake process. ?? 2007 Geological Society of America.

  8. Numerical simulation of wind-sand movement in the reversed flow region of a sand dune with a bridge built downstream.

    Science.gov (United States)

    He, Wei; Huang, Ning; Xu, Bin; Wang, Wenbo

    2018-04-23

    A bridge built inside the reversed flow region of a sand dune will change the characteristics of wind-sand movement in this region. The Reynolds-averaged Navier-Stokes simulation and discrete particle tracing are used to simulate the wind-sand movement around a sand dune with a bridge built inside the reversed region. Three cases with different bridge positions are studied. The results show that 1) compared with the isolated dune case, a tall bridge built at the leeward toe leads to an increase in the deposition rate on the leeward slope and a longer reversed flow region downstream of the sand dune; meanwhile, the high speed of crosswind on the bridge indicates that some measures should be taken to protect trains from strong crosswind; 2) a low bridge at the leeward toe has little effect on the sand deposition and reversed flow region of the dune; however, low sand transport rate and crosswind speed on the bridge show that anti-crosswind/sand measures should be taken according to the actual situation and 3) a low bridge on the leeward slope has little effect on the length of reversed flow region, however, high crosswind speed and sand flux on the bridge reveal the need of anti-crosswind/sand measures on the bridge. Moreover, the bridges in the reversed flow region increase the sand flux near the leeward crest; as a result, the moving patterns of the sand dune are changed.

  9. Memory-induced sign reversals of the spatial cross-correlation for particles in viscoelastic shear flows

    International Nuclear Information System (INIS)

    Sauga, Ako; Laas, Katrin; Mankin, Romi

    2015-01-01

    Highlights: • Cross-correlation (CC) of coordinates of particles in viscoelastic shear flows is discussed. • Expressions for CC functions subjected to both internal and external noises are presented. • Impact of internal and external noises on CC functions are compared. • Memory-induced reentrant sign reversals of the spatial cross-moment are established. - Abstract: The behavior of shear-induced cross-correlation functions between particle fluctuations along orthogonal directions in the shear plane for harmonically trapped Brownian particles in a viscoelastic shear flow is studied. A generalized Langevin equation with a power-law-type memory kernel is used to model the complex structure of the viscoelastic media. Interaction with fluctuations of environmental parameters is modeled by a multiplicative white Gaussian noise, by an internal fractional Gaussian noise, and by an additive external white noise. It is shown that the presence of a memory has a profound effect on the behavior of the cross-correlation functions. Particularly, memory-induced reentrant sign reversals of the spatial cross-moment between orthogonal random displacements of a particle are established, i.e., an increase of the memory exponent can cause the sign reversal from positive to negative, but by a further increase of the memory exponent a reentrant transition from negative to positive values appears. Similarities and differences between the behavior of the models with additive internal and external noises are considered. It is shown that additive external and internal noises cause qualitatively different dependencies of the cross-correlation functions on the time lag. The occurrence of energetic instability due to the influence of multiplicative noise is also discussed.

  10. Postoperative Reverse Remodeling and Symptomatic Improvement in Normal-Flow Low-Gradient Aortic Stenosis After Aortic Valve Replacement.

    Science.gov (United States)

    Carter-Storch, Rasmus; Møller, Jacob E; Christensen, Nicolaj L; Irmukhadenov, Akhmadjon; Rasmussen, Lars M; Pecini, Redi; Øvrehus, Kristian A; Søndergård, Eva V; Marcussen, Niels; Dahl, Jordi S

    2017-12-01

    Severe aortic stenosis (AS) most often presents with reduced aortic valve area (gradient (≥40 mm Hg; normal-flow high-gradient AS) or low mean gradient (normal-flow low-gradient [NFLG] AS). The benefit of aortic valve replacement (AVR) among NFLG patients is controversial. We compared the impact of NFLG condition on preoperative left ventricular (LV) remodeling and myocardial fibrosis and postoperative remodeling and symptomatic benefit. Eighty-seven consecutive patients with reduced aortic valve area and normal stroke volume index undergoing AVR underwent echocardiography, magnetic resonance imaging, a 6-minute walk test, and measurement of natriuretic peptides before and 1 year after AVR. Myocardial fibrosis was assessed from magnetic resonance imaging. Patients were stratified as NFLG or normal-flow high-gradient. In total, 33 patients (38%) had NFLG. Before AVR, they were characterized by similar symptom burden but less severe AS measured by aortic valve area index (0.50±0.09 versus 0.40±0.08 cm 2 /m 2 ; P gradient condition independently predicted change in LV mass index. Patients with NFLG had less severe AS and LV remodeling than patients with normal-flow high-gradient. Furthermore, NFLG patients experienced less reverse remodeling but the same symptomatic benefit. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02316587. © 2017 American Heart Association, Inc.

  11. ExB flow shear and enhanced confinement in the Madison Symmetric Torus reversed-field pinch

    International Nuclear Information System (INIS)

    Chapman, B.E.; Almagri, A.F.; Anderson, J.K.; Chiang, C.; Craig, D.; Fiksel, G.; Lanier, N.E.; Prager, S.C.; Sarff, J.S.; Stoneking, M.R.; Terry, P.W.

    1998-01-01

    Strong ExB flow shear occurs in the edge of three types of enhanced confinement discharge in the Madison Symmetric Torus [Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch. Measurements in standard (low confinement) discharges indicate that global magnetic fluctuations drive particle and energy transport in the plasma core, while electrostatic fluctuations drive particle transport in the plasma edge. This paper explores possible contributions of ExB flow shear to the reduction of both the magnetic and electrostatic fluctuations and, thus, the improved confinement. In one case, shear in the ExB flow occurs when the edge plasma is biased. Biased discharges exhibit changes in the edge electrostatic fluctuations and improved particle confinement. In two other cases, the flow shear emerges (1) when auxiliary current is driven in the edge and (2) spontaneously, following sawtooth crashes. Both edge electrostatic and global magnetic fluctuations are reduced in these discharges, and both particle and energy confinement improve. copyright 1998 American Institute of Physics

  12. Reservoir simulation with MUFITS code: Extension for double porosity reservoirs and flows in horizontal wells

    Science.gov (United States)

    Afanasyev, Andrey

    2017-04-01

    Numerical modelling of multiphase flows in porous medium is necessary in many applications concerning subsurface utilization. An incomplete list of those applications includes oil and gas fields exploration, underground carbon dioxide storage and geothermal energy production. The numerical simulations are conducted using complicated computer programs called reservoir simulators. A robust simulator should include a wide range of modelling options covering various exploration techniques, rock and fluid properties, and geological settings. In this work we present a recent development of new options in MUFITS code [1]. The first option concerns modelling of multiphase flows in double-porosity double-permeability reservoirs. We describe internal representation of reservoir models in MUFITS, which are constructed as a 3D graph of grid blocks, pipe segments, interfaces, etc. In case of double porosity reservoir, two linked nodes of the graph correspond to a grid cell. We simulate the 6th SPE comparative problem [2] and a five-spot geothermal production problem to validate the option. The second option concerns modelling of flows in porous medium coupled with flows in horizontal wells that are represented in the 3D graph as a sequence of pipe segments linked with pipe junctions. The well completions link the pipe segments with reservoir. The hydraulics in the wellbore, i.e. the frictional pressure drop, is calculated in accordance with Haaland's formula. We validate the option against the 7th SPE comparative problem [3]. We acknowledge financial support by the Russian Foundation for Basic Research (project No RFBR-15-31-20585). References [1] Afanasyev, A. MUFITS Reservoir Simulation Software (www.mufits.imec.msu.ru). [2] Firoozabadi A. et al. Sixth SPE Comparative Solution Project: Dual-Porosity Simulators // J. Petrol. Tech. 1990. V.42. N.6. P.710-715. [3] Nghiem L., et al. Seventh SPE Comparative Solution Project: Modelling of Horizontal Wells in Reservoir Simulation

  13. Extension of analytical indicial aerodynamics to generic trapezoidal wings in subsonic flow

    Directory of Open Access Journals (Sweden)

    Andrea DA RONCH

    2018-04-01

    Full Text Available Analytical indicial aerodynamic functions are calculated for several trapezoidal wings in subsonic flow, with a Mach number 0.3 ≤ Ma ≤ 0.7. The formulation herein proposed extends well-known aerodynamic theories, which are limited to thin aerofoils in incompressible flow, to generic trapezoidal wing planforms. Firstly, a thorough study is executed to assess the accuracy and limitation of analytical predictions, using unsteady results from two state-of-the-art computational fluid dynamics solvers as cross-validated benchmarks. Indicial functions are calculated for a step change in the angle of attack and for a sharp-edge gust, each for four wing configurations and three Mach numbers. Then, analytical and computational indicial responses are used to predict dynamic derivatives and the maximum lift coefficient following an encounter with a one-minus-cosine gust. It is found that the analytical results are in excellent agreement with the computational results for all test cases. In particular, the deviation of the analytical results from the computational results is within the scatter or uncertainty in the data arising from using two computational fluid dynamics solvers. This indicates the usefulness of the developed analytical theories. Keywords: Analytical approach, CFD, Compressible flow, Gust response, Indicial aerodynamics, Trapezoidal wing

  14. LBflow: An extensible lattice Boltzmann framework for the simulation of geophysical flows. Part II: usage and validation

    Science.gov (United States)

    Llewellin, E. W.

    2010-02-01

    LBflow is a flexible, extensible implementation of the lattice Boltzmann method, developed with geophysical applications in mind. The theoretical basis for LBflow, and its implementation, are presented in the companion paper, 'Part I'. This article covers the practical usage of LBflow and presents guidelines for obtaining optimal results from available computing power. The relationships among simulation resolution, accuracy, runtime and memory requirements are investigated in detail. Particular attention is paid to the origin, quantification and minimization of errors. LBflow is validated against analytical, numerical and experimental results for a range of three-dimensional flow geometries. The fluid conductance of prismatic pipes with various cross sections is calculated with LBflow and found to be in excellent agreement with published results. Simulated flow along sinusoidally constricted pipes gives good agreement with experimental data for a wide range of Reynolds number. The permeability of packs of spheres is determined and shown to be in excellent agreement with analytical results. The accuracy of internal flow patterns within the investigated geometries is also in excellent quantitative agreement with published data. The development of vortices within a sinusoidally constricted pipe with increasing Reynolds number is shown, demonstrating the insight that LBflow can offer as a 'virtual laboratory' for fluid flow.

  15. Rotating turbulent Rayleigh-Bénard convection subject to harmonically forced flow reversals

    NARCIS (Netherlands)

    Geurts, B.J.; Kunnen, R.P.J.

    2014-01-01

    The characteristics of turbulent flow in a cylindrical Rayleigh–B´enard convection cell which can be modified considerably in case rotation is included in the dynamics. By incorporating the additional effects of an Euler force, i.e., effects induced by nonconstant rotation rates, a remarkably strong

  16. Rotating turbulent Rayleigh–Bénard convection subject to harmonically forced flow reversals

    NARCIS (Netherlands)

    Geurts, Bernardus J.; Kunnen, Rudie P.J.

    2014-01-01

    The characteristics of turbulent flow in a cylindrical Rayleigh–Bénard convection cell which can be modified considerably in case rotation is included in the dynamics. By incorporating the additional effects of an Euler force, i.e., effects induced by non-constant rotation rates, a remarkably strong

  17. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken

  18. The quantitative visualisation of the flow in a 1/10th scale model thrust reverser at the Aircraft Research Association, Bedford

    Science.gov (United States)

    Bryanston-Cross, P.; Sale, R.

    1992-06-01

    A series of laser visualization measurements has been made to both visualize and map the velocity and direction of the transonic flow from a 1/10th scale model of a thrust reverser. The measurements which have been made by injecting micron sized water droplets into the flow, used two techniques to provide a quantitative measurement of the flow field. The first technique LLS (laser light sheet) provided a general view of the flow, whereas a second pulse laser technique PIV (particle image velocimetry) made a specific measurement in the vicinity of the thrust reverser's 'kicker' plate to map the velocity and direction of the exit flow. This successful study is, to the best of the author's knowledge, the first example of a whole field quantitative visualization being achieved in such a turbulent transonic flow.

  19. Family structure and fertility in Taiwan: an extension and modification of Caldwell's wealth flows theory.

    Science.gov (United States)

    Hsuing, P C

    1988-06-01

    Based on the data from a nationwide survey of labor force participation conducted in 1985 by the Office of the Directorate-General of Budget, Accounting and Statistics, Executive Yuan, Republic of China, this project tries to modify Caldwell's Wealth Flows Theory in order to analyze fertility behavior of married women. Caldwell's Wealth Flows Theory indicates that a patriarchal family has a significant effect on fertility. Unless the patriarchal family structure is replaced by a nuclear family system, he claims, fertility levels will remain relatively high in developing countries. However, he does not discuss social factors which may influence the process of change in the family structure and which factors in the patriarchal family may influence fertility. To make up this shortcoming, this paper shows that female educational level, employment patterns, and occupational prestige brings about change in the family structure. This research also indicates that women with higher education and occupational prestige have lower fertility. In addition, it finds that female occupational status is a main factor to bring about change in the family structure. (author's)

  20. Flow reversal at low voltage and low frequency in a microfabricated ac electrokinetic pump

    DEFF Research Database (Denmark)

    Gregersen, Misha Marie; Olesen, Laurits Højgaard; Brask, Anders

    2007-01-01

    measured in a regime, where both the applied voltage and the frequency are low, Vrms1.5 V and f20 kHz, compared to previously investigated parameter ranges. The impedance spectrum has been thoroughly measured and analyzed in terms of an equivalent circuit diagram to rule out trivial circuit explanations......Microfluidic chips have been fabricated in Pyrex glass to study electrokinetic pumping generated by a low-voltage ac bias applied to an in-channel asymmetric metallic electrode array. A measurement procedure has been established and followed carefully resulting in a high degree of reproducibility...... of the measurements over several days. A large coverage fraction of the electrode array in the microfluidic channels has led to an increased sensitivity allowing for pumping measurements at low bias voltages. Depending on the ionic concentration a hitherto unobserved reversal of the pumping direction has been...

  1. Sheared flow layer formation in tokamak plasmas with reversed magnetic shear

    International Nuclear Information System (INIS)

    Dong, J.Q.; Long, Y.X.; Mou, Z.Z.; Zhang, J.H.; Li, J.Q.

    2005-01-01

    Sheared flow layer (SFL) formation due to magnetic energy release through tearing-reconnections in tokamak plasmas is investigated. The characteristics of the SFLs created in the development of double tearing mode, mediated by electron viscosity in configurations with non-monotonic safety factor q profiles and, therefore, two rational flux surfaces of same q value, are analyzed in detail as an example. Quasi-linear simulations demonstrate that the sheared flows induced by the mode have desirable characteristics (lying at the boundaries of the magnetic islands), and sufficient levels required for internal transport barrier (ITB) formation. A possible correlation of the SFLs with experimental observations, that double transport barrier structures are preferentially formed in proximity of the two rational surfaces, is also proffered. (author)

  2. One- and two-dimensional Stirling machine simulation using experimentally generated reversing flow turbuulence models

    International Nuclear Information System (INIS)

    Goldberg, L.F.

    1990-08-01

    The activities described in this report do not constitute a continuum but rather a series of linked smaller investigations in the general area of one- and two-dimensional Stirling machine simulation. The initial impetus for these investigations was the development and construction of the Mechanical Engineering Test Rig (METR) under a grant awarded by NASA to Dr. Terry Simon at the Department of Mechanical Engineering, University of Minnesota. The purpose of the METR is to provide experimental data on oscillating turbulent flows in Stirling machine working fluid flow path components (heater, cooler, regenerator, etc.) with particular emphasis on laminar/turbulent flow transitions. Hence, the initial goals for the grant awarded by NASA were, broadly, to provide computer simulation backup for the design of the METR and to analyze the results produced. This was envisaged in two phases: First, to apply an existing one-dimensional Stirling machine simulation code to the METR and second, to adapt a two-dimensional fluid mechanics code which had been developed for simulating high Rayleigh number buoyant cavity flows to the METR. The key aspect of this latter component was the development of an appropriate turbulence model suitable for generalized application to Stirling simulation. A final-step was then to apply the two-dimensional code to an existing Stirling machine for which adequate experimental data exist. The work described herein was carried out over a period of three years on a part-time basis. Forty percent of the first year's funding was provided as a match to the NASA funds by the Underground Space Center, University of Minnesota, which also made its computing facilities available to the project at no charge

  3. Highly efficient reversible addition-fragmentation chain-transfer polymerization in ethanol/water via flow chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Piaoran [Case Western Reserve Univ., Cleveland, OH (United States); Cao, Peng -Fei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Su, Zhe [Case Western Reserve Univ., Cleveland, OH (United States); Advincula, Rigoberto [Case Western Reserve Univ., Cleveland, OH (United States)

    2017-03-23

    Here, utilization of a flow reactor under high pressure allows highly efficient polymer synthesis via reversible addition–fragmentation chain-transfer (RAFT) polymerization in an aqueous system. Compared with the batch reaction, the flow reactor allows the RAFT polymerization to be performed in a high-efficiency manner at the same temperature. The adjustable pressure of the system allows further elevation of the reaction temperature and hence faster polymerization. Other reaction parameters, such as flow rate and initiator concentration, were also well studied to tune the monomer conversion and the molar mass dispersity (Ð) of the obtained polymers. Gel permeation chromatography, nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopies (FTIR) were utilized to monitor the polymerization process. With the initiator concentration of 0.15 mmol L–1, polymerization of poly(ethylene glycol) methyl ethermethacrylate with monomer conversion of 52% at 100 °C under 73 bar can be achieved within 40 min with narrow molar mass dispersity (D) Ð (<1.25). The strategy developed here provides a method to produce well-defined polymers via RAFT polymerization with high efficiency in a continuous manner.

  4. Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack

    KAUST Repository

    Hatzell, Marta C.

    2013-11-01

    Ammonium bicarbonate has recently been demonstrated to be an excellent thermolytic solution for energy generation in reverse electrodialysis (RED) stacks. However, operating RED stacks at room temperatures can promote gaseous bubble (CO2, NH3) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were analyzed to determine how both fluid flow and the buildup and removal of bubbles affected performance. In the presence of a spacer, the membrane resistance increased by ~50Ω, resulting in a decrease in power density by 30% from 0.140Wm-2 to 0.093Wm-2. Shorter channels reduced concentration polarization affects, and resulted in 3-23% higher limiting current density. Gas accumulation was minimized through the use of short vertically aligned channels, and consequently the amount of the membrane area covered by bubbles was reduced from ~20% to 7% which caused a 12% increase in power density. As ammonium bicarbonate RED systems are scaled up, attention to channel aspect ratio, length, and alignment will enable more stable performance. © 2013 Elsevier B.V.

  5. Brown and polar bear Y chromosomes reveal extensive male-biased gene flow within brother lineages.

    Science.gov (United States)

    Bidon, Tobias; Janke, Axel; Fain, Steven R; Eiken, Hans Geir; Hagen, Snorre B; Saarma, Urmas; Hallström, Björn M; Lecomte, Nicolas; Hailer, Frank

    2014-06-01

    Brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial DNA (mtDNA) or were geographically restricted. The male-specific Y chromosome, a natural counterpart to mtDNA, has remained underexplored. Although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most mammals. We developed 13 novel Y-chromosomal sequence and microsatellite markers from the polar bear genome and screened these in a broad geographic sample of 130 brown and polar bears. We also analyzed a 390-kb-long Y-chromosomal scaffold using sequencing data from published male ursine genomes. Y chromosome evidence support the emerging understanding that brown and polar bears started to diverge no later than the Middle Pleistocene. Contrary to mtDNA patterns, we found 1) brown and polar bears to be reciprocally monophyletic sister (or rather brother) lineages, without signals of introgression, 2) male-biased gene flow across continents and on phylogeographic time scales, and 3) male dispersal that links the Alaskan ABC islands population to mainland brown bears. Due to female philopatry, mtDNA provides a highly structured estimate of population differentiation, while male-biased gene flow is a homogenizing force for nuclear genetic variation. Our findings highlight the importance of analyzing both maternally and paternally inherited loci for a comprehensive view of phylogeographic history, and that mtDNA-based phylogeographic studies of many mammals should be reevaluated. Recent advances in sequencing technology render the analysis of Y-chromosomal variation feasible, even in nonmodel organisms. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e

  6. Electromagnetic treatment to old Alzheimer's mice reverses β-amyloid deposition, modifies cerebral blood flow, and provides selected cognitive benefit.

    Directory of Open Access Journals (Sweden)

    Gary W Arendash

    Full Text Available Few studies have investigated physiologic and cognitive effects of "long-term" electromagnetic field (EMF exposure in humans or animals. Our recent studies have provided initial insight into the long-term impact of adulthood EMF exposure (GSM, pulsed/modulated, 918 MHz, 0.25-1.05 W/kg by showing 6+ months of daily EMF treatment protects against or reverses cognitive impairment in Alzheimer's transgenic (Tg mice, while even having cognitive benefit to normal mice. Mechanistically, EMF-induced cognitive benefits involve suppression of brain β-amyloid (Aβ aggregation/deposition in Tg mice and brain mitochondrial enhancement in both Tg and normal mice. The present study extends this work by showing that daily EMF treatment given to very old (21-27 month Tg mice over a 2-month period reverses their very advanced brain Aβ aggregation/deposition. These very old Tg mice and their normal littermates together showed an increase in general memory function in the Y-maze task, although not in more complex tasks. Measurement of both body and brain temperature at intervals during the 2-month EMF treatment, as well as in a separate group of Tg mice during a 12-day treatment period, revealed no appreciable increases in brain temperature (and no/slight increases in body temperature during EMF "ON" periods. Thus, the neuropathologic/cognitive benefits of EMF treatment occur without brain hyperthermia. Finally, regional cerebral blood flow in cerebral cortex was determined to be reduced in both Tg and normal mice after 2 months of EMF treatment, most probably through cerebrovascular constriction induced by freed/disaggregated Aβ (Tg mice and slight body hyperthermia during "ON" periods. These results demonstrate that long-term EMF treatment can provide general cognitive benefit to very old Alzheimer's Tg mice and normal mice, as well as reversal of advanced Aβ neuropathology in Tg mice without brain heating. Results further underscore the potential for EMF

  7. Start-up assist by magnetized plasma flow injection in TPE-RX reversed-field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Asai, T. [College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)]. E-mail: asai@phys.cst.nihon-u.ac.jp; Nagata, M. [Graduate School of Engineering, University of Hyogo, Himeji (Japan); Koguchi, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Hirano, Y. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Sakakita, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Yambe, K. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Kiyama, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)

    2006-11-15

    A reversed-field pinch (RFP) start-up assisted by a magnetized plasma flow injection was demonstrated for the first time on a TPE-RX machine. This sequence of experiments aimed to establish a new method of ionization, gas-fill and helicity injection in the start-up phase of an RFP. In this start-up method, magnetized and well-ionized plasma is formed by a magnetized coaxial plasma gun and injected into the torus chamber as an initial pre-ionized plasma for RFP formation. In the initial experiments, attenuated density pump-out and comparatively slow decay of the toroidal flux and plasma current were observed as evidence of its being an effective start-up method.

  8. Reverse Flow Routing in a Bayesian Framework Using a GPU-accelerated 2D Shallow Water Model

    Science.gov (United States)

    D'Oria, M.; Ferrari, A.; Mignosa, P.; Tanda, M. G.; Vacondio, R.

    2017-12-01

    Knowledge of discharge hydrographs in specific sites of natural rivers is important for water resource management, flood frequency analysis, design of structures, etc. Many times, the flood hydrograph is needed in a river section upstream of a monitoring station; here the flood wave differs from the upstream one because of the effects of resistance, channel storage, lateral inflow, etc. Reverse flow routing is a method that allows obtaining hydrographs in upstream ungauged stations using information available at downstream monitored sites. In this study, we propose an inverse procedure, based on a Bayesian Geostatistical Approach, to solve the reverse problem. The upstream flow values over time (parameters) are considered as random variables and a-priori information about the parameters and observations (downstream discharge or water level values) are combined together in a Bayesian framework. The methodology needs a forward model of the considered open channel that includes the upstream ungauged station and the downstream gauged one and it is able to describe, with sufficient accuracy, the hydraulic routing processes. In many real cases, especially when large floodable areas are involved, a 1D hydraulic model is not able to capture the complex river hydrodynamic and a 2D model must be used. The inverse procedure requires a high number of flow model run to linearize the forward problem through multiple evaluations of a Jacobian matrix (sensitivity of each observation to each parameter) using a finite difference approach. For this reason, the computational efficiency of the forward model is a crucial element to reduce the overall computational costs. Therefore, in this work we used, in combination with the inverse procedure, a GPU-parallel numerical model for the solution of the 2D Shallow Water equations (implemented in CUDA/C++ code) that allows achieving ratio of physical to computational time of about 500-1000 (depending on the test case features). In addition

  9. Simulation of the flow-reversal effect in dual channel CICC for ITER

    CERN Document Server

    Bottura, L; Calvi, M; Herzog, R; Marinucci, C

    2007-01-01

    The discovery of an upward counter flow of helium in the outer annulus of the vertically oriented and top-to-bottom cooled ITER PFFSJS (Poloidal Field Coil-Full Size Joint Sample) in 2002 led to closer investigations of the effect because it may lead to a reduction of the operational margin of the superconductor used in the ITER environment. Recently, further thermo-hydraulic experiments were carried out on the TFAS2 sample (Toroidal Field Advanced Strand sample 2) with the intent to asses the effect in detail. First investigations confirmed the initial assumption that the origin of the effect lies in the buoyancy of the heated, and thus less dense, helium in the outer annulus of the cable. The helium there is in good contact with the superconducting strands heated by neutron irradiation, ac losses or heat influx, but is thermally and hydraulically less well coupled to the downward flowing helium in the central channel. This paper presents an analysis of the TFAS2 experiments using the simulation program THEA...

  10. Chinese CO2 emission flows have reversed since the global financial crisis.

    Science.gov (United States)

    Mi, Zhifu; Meng, Jing; Guan, Dabo; Shan, Yuli; Song, Malin; Wei, Yi-Ming; Liu, Zhu; Hubacek, Klaus

    2017-11-23

    This study seeks to estimate the carbon implications of recent changes in China's economic development patterns and role in global trade in the post-financial-crisis era. We utilised the latest socioeconomic datasets to compile China's 2012 multiregional input-output (MRIO) table. Environmentally extended input-output analysis and structural decomposition analysis (SDA) were applied to investigate the driving forces behind changes in CO 2 emissions embodied in China's domestic and foreign trade from 2007 to 2012. Here we show that emission flow patterns have changed greatly in both domestic and foreign trade since the financial crisis. Some economically less developed regions, such as Southwest China, have shifted from being a net emission exporter to being a net emission importer. In terms of foreign trade, emissions embodied in China's exports declined from 2007 to 2012 mainly due to changes in production structure and efficiency gains, while developing countries became the major destination of China's export emissions.

  11. Spatial heterogeneity of biofouling under different cross-flow velocities in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia

    2016-09-06

    The spatially heterogeneous distribution of biofouling in spiral wound membrane systems restricts (i) the water distribution over the membrane surface and therefore (ii) the membrane-based water treatment. The objective of the study was to assess the spatial heterogeneity of biofilm development over the membrane fouling simulator (MFS) length (inlet and outlet part) at three different cross-flow velocities (0.08, 0.12 and 0.16 m/s). The MFS contained sheets of membrane and feed spacer and simulated the first 0.20 m of spiral-wound membrane modules where biofouling accumulates the most in practice. In-situ non-destructive oxygen imaging using planar optodes was applied to determine the biofilm spatially resolved activity and heterogeneity.

  12. Lubricant flow analysis for effective lubrication of tractor forward/reverse clutch

    Directory of Open Access Journals (Sweden)

    Daekyung Noh

    2017-04-01

    Full Text Available Owing to the high power requirements of tractors, their low-power transmission gears often experience durability problems such as burning of the clutch. The operation of tractors under high load conditions also causes clutch slip, with the consequent longer operation duration exacerbating the burning of the friction plate. Solving this problem requires effective lubricant distribution. This was achieved in the present study by the development of an analysis model for predicting the lubricant flow rate. The reliability of the model was verified by comparing its predictions for various operation conditions with experimental measurements. Using the model, it was determined that effective distribution of the lubricant could be achieved without significant modification of the system, by only adjusting the gaps between the clutch piston and the housing, and between the separation plates and the case. Keywords: Mechanical engineering

  13. Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT Polymerization Using Continuous Flow Processing

    Directory of Open Access Journals (Sweden)

    Nenad Micic

    2014-01-01

    Full Text Available A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The batch polymerizations were carried out in a series of different glass vessels, using either magnetic or overhead stirring, and different modes of heating: Microwave irradiation or conductive heating in an oil bath. The continuous process was conducted in a prototype tubular flow reactor, consisting of 6 mm ID stainless steel tubing, fitted with static mixers. Both reactor types were tested for polymerizations of the acid functional monomers acrylic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in water at 80 °C with reaction times of 30 to 40 min. By monitoring the temperature during the exothermic polymerization process, it was observed that the type and size of reactor had a significant influence on the temperature profile of the reaction.

  14. Temporary targeted renal blood flow interruption using a reverse thermosensitive polymer to facilitate bloodless partial nephrectomy: a swine survival study.

    Science.gov (United States)

    Harty, Niall J; Laskey, Daniel H; Moinzadeh, Alireza; Flacke, Sebastian; Benn, James A; Villani, Rosanna; Kalra, Aarti; Libertino, John A; Madras, Peter N

    2012-09-01

    What's known on the subject? and What does the study add? Lumagel™ is a reverse thermosensitive polymer (RTP) that has previously been described in the literature as providing temporary vascular occlusion to allow for bloodless partial nephrectomy (PN) while maintaining blood flow to the untargeted portion of the kidney. At body temperature, Lumagel™ has the consistency of a viscous gel but upon cooling rapidly converts to a liquid state and does not reconstitute thereafter. This property has allowed for it to be used in situations requiring temporary vascular occlusion. Previous experience with similar RTPs in coronary arteries proved successful, with no detectable adverse events. We have previously described our technique for temporary vascular occlusion of the main renal artery, as well as segmental and sub-segmental renal branches, to allow for bloodless PN in either an open or minimally invasive approach. These experiments were performed in the acute setting. This study is a two-armed survival trial to assess whether this RTP is as safe as hilar clamping for bloodless PN. Surviving animals showed normal growth after using the RTP, absence of toxicity, no organ dysfunction, and no pathological changes attributable to the RTP. We conclude that Lumagel™ is as safe as conventional PN with hilar clamping, while adding the advantage of uninterrupted perfusion during renal resection. To examine whether randomly selected regions of the kidney could undergo temporary flow interruption with a reverse thermosensitive polymer (RTP), Lumagel™ (Pluromed, Inc., Woburn, MA, USA), followed by partial nephrectomy (PN), without adding risks beyond those encountered in the same procedure with the use of hilar clamping. A two-armed (RTP vs hilar clamp), 6-week swine survival study was performed. Four swine underwent PN using hilar clamps, while six underwent PN with flow interruption using the RTP. The RTP, administered angiographically, was used for intraluminal occlusion

  15. Cost-optimal power system extension under flow-based market coupling and high shares of photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Inst. of Energy Economics; Cherevatskiy, Stanislav; Troester, Eckehard; Brown, Tom [Energynautics GmbH, Langen (Germany)

    2012-07-01

    Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems such as the European power system. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is demonstrated on a simplified three-node model where it is found to be stable and convergent. It is then scaled to the European level in order to find the optimal power system infrastructure development under the prescription of strongly decreasing CO{sub 2} emissions in Europe until 2050 with a specific focus on photovoltaic (PV) power. (orig.)

  16. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow...... operators. Reversible flowcharts are r- Turing-complete, meaning that they can simuluate reversible Turing machines without garbage data. We also demonstrate the injectivization of classical flowcharts into reversible flowcharts. The reversible flowchart computation model provides a theoretical...

  17. Experimental demonstration of the reverse flow catalytic membrane reactor concept for energy efficient syngas production. Part 1: Influence of operating conditions

    NARCIS (Netherlands)

    Smit, J.; Bekink, G.J.; Sint Annaland, van M.; Kuipers, J.A.M.

    2007-01-01

    In this contribution the technical feasibility of the reverse flow catalytic membrane reactor (RFCMR) concept with porous membranes for energy efficient syngas production is investigated. In earlier work an experimental proof of principle was already provided [Smit, J., Bekink, G.J., van Sint

  18. Evidence for a new geomagnetic reversal from lava flows in Idaho: discussion of short polarity reversals in the Brunhes and late Matuyama Polarity Chrons

    Science.gov (United States)

    Champion, D.E.; Lanphere, M.A.; Kuntz, M.A.

    1988-01-01

    K-Ar ages and paleomagnetic data for basalt samples from a new core hole (site E) at the Idaho National Engineering Laboratory (INEL) indicate that the age of the reversed polarity event recorded in Snake River Plain lavas is older than 465 ?? 50 ka (1000 years before present) reported previously by Champion et al. (1981). A review of data documenting short reversal records from volcanic and sedimentary rocks shows that there is evidence for eight polarity subchrons in the Brunhes and two besides the Jaramillo in the late Matuyama. These 10 short subchrons begin to indicate the many short events that Cox (1968) hypothesized must exist if polarity interval lengths have a Poisson distribution. The mean sustained polarity interval length since late Matuyama Chron time is 90 000 years. The similarity of this number with the 105-year period of the Earth's orbital eccentricity suggests anew that linkage between geomagnetic, paleoclimatic, and possible underlying Earth orbital parameters should be evaluated. -from Authors

  19. Determination of Diffusion Coefficients and Activation Energy of Selected Organic Liquids using Reversed-Flow Gas Chromatographic Technique

    International Nuclear Information System (INIS)

    Khalisanni Khalid; Rashid Atta Khan; Sharifuddin Mohd Zain

    2012-01-01

    Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound agreement between theoretical values of diffusion coefficients and experimental evidence. (author)

  20. Reverse flow injection spectrophotometric determination of ciprofloxacin in pharmaceuticals using iron from soil as a green reagent

    Science.gov (United States)

    Palamy, Sysay; Ruengsitagoon, Wirat

    2018-02-01

    A novel reverse flow injection spectrophotometric method for the determination of ciprofloxacin was successfully combined with the on-line introduction of an iron solution extracted from soil as green reagent. The assay was optimized by a univariate method to select the optimum conditions for the highest absorbance and highest stability of the complex. Beer-Lambert's law (λmax = 440 nm) is obeyed in the range 0.5-50 μg mL- 1 with a correlation coefficient (r2) of 0.9976 and 0.9996 using soil as green reagent from Khon Kaen, Thailand and Vientiane, Laos, respectively. The average percentage recoveries were in the range of 98.55-102.14% and the precision was in the range of 0.80-1.73%. The limit of detection and the limit of quantitation were 0.20 and 0.69 μg mL- 1, respectively, with a sampling rate of over 46 samples h- 1. The method was successfully applied to the determination of ciprofloxacin in commercial pharmaceutical formulations. The results were in good agreement with those obtained by the reference HPLC method using a t-test at 95% of confidence level for comparison. This method is suitable for laboratories looking for alternative analytical methods using green reagents.

  1. Bayesian uncertainty quantification for flows in heterogeneous porous media using reversible jump Markov chain Monte Carlo methods

    KAUST Repository

    Mondal, A.

    2010-03-01

    In this paper, we study the uncertainty quantification in inverse problems for flows in heterogeneous porous media. Reversible jump Markov chain Monte Carlo algorithms (MCMC) are used for hierarchical modeling of channelized permeability fields. Within each channel, the permeability is assumed to have a lognormal distribution. Uncertainty quantification in history matching is carried out hierarchically by constructing geologic facies boundaries as well as permeability fields within each facies using dynamic data such as production data. The search with Metropolis-Hastings algorithm results in very low acceptance rate, and consequently, the computations are CPU demanding. To speed-up the computations, we use a two-stage MCMC that utilizes upscaled models to screen the proposals. In our numerical results, we assume that the channels intersect the wells and the intersection locations are known. Our results show that the proposed algorithms are capable of capturing the channel boundaries and describe the permeability variations within the channels using dynamic production history at the wells. © 2009 Elsevier Ltd. All rights reserved.

  2. Sequential determination of multi-nutrient elements in natural water samples with a reverse flow injection system.

    Science.gov (United States)

    Lin, Kunning; Ma, Jian; Yuan, Dongxing; Feng, Sichao; Su, Haitao; Huang, Yongming; Shangguan, Qipei

    2017-05-15

    An integrated system was developed for automatic and sequential determination of NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ in natural waters based on reverse flow injection analysis combined with spectrophotometric detection. The system operation was controlled by a single chip microcomputer and laboratory-programmed software written in LabVIEW. The experimental parameters for each nutrient element analysis were optimized based on a univariate experimental design, and interferences from common ions were evaluated. The upper limits of the linear range (along with detection limit, µmolL -1 ) of the proposed method was 20 (0.03), 200 (0.7), 12 (0.3), 5 (0.03), 5 (0.03), 9 (0.2) µmolL -1 , for NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ , respectively. The relative standard deviations were below 5% (n=9-13) and the recoveries varied from 88.0±1.0% to 104.5±1.0% for spiked water samples. The sample throughput was about 20h -1 . This system has been successfully applied for the determination of multi-nutrient elements in different kinds of water samples and showed good agreement with reference methods (slope 1.0260±0.0043, R 2 =0.9991, n=50). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Surgical treatment of tricuspid valve insufficiency promotes early reverse remodeling in patients with axial-flow left ventricular assist devices.

    Science.gov (United States)

    Maltais, Simon; Topilsky, Yan; Tchantchaleishvili, Vakhtang; McKellar, Stephen H; Durham, Lucian A; Joyce, Lyle D; Daly, Richard C; Park, Soon J

    2012-06-01

    The HeartMate II (Thoratec Corp, Pleasanton, Calif) continuous-flow left ventricular assist device has emerged as the standard of care for patients with advanced heart failure. The objective of this study was to assess the safety and early effectiveness of concomitant tricuspid valve procedures in patients undergoing implantation of a HeartMate II device. From February 2007 to April 2010, 83 patients underwent HeartMate II left ventricular assist device implantation. Of these, 37 patients had concomitant tricuspid valve procedures (32 repairs, 5 replacements) for severe tricuspid regurgitation. The effects of a tricuspid valve procedure on tricuspid regurgitation and right ventricular remodeling were assessed comparing echocardiographic findings at baseline and 30 days after left ventricular assist device implantation. Overall survival was also compared. Patients undergoing a concomitant tricuspid valve procedure had more tricuspid regurgitation (vena contracta, 5.6 ± 2.1 mm vs 2.9 ± 2.0 mm; P tricuspid regurgitation was worse in patients who underwent left ventricular assist device implantation alone (+18.6%), whereas it improved significantly in patients undergoing a concomitant tricuspid valve procedure (-50.2%) (P = .005). A corresponding significant reduction in right ventricular end-diastolic area (33.6% ± 6.2% vs 30.1% ± 9.7%; P = .03) and a trend toward better right ventricular function (55.5% ± 79.7% vs 35.7% ± 60.5%; P = .28) were noted in patients undergoing a concomitant tricuspid valve procedure. Survival was comparable between the 2 groups. In patients with severe tricuspid regurgitation undergoing left ventricular assist device implantation, a concomitant tricuspid valve procedure effectively reduces tricuspid regurgitation and promotes reverse remodeling of the right ventricle. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  4. Rotation profile flattening and toroidal flow shear reversal due to the coupling of magnetic islands in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B.; Grierson, B. A.; Okabayashi, M. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Chen, M.; Domier, C. W.; Luhmann, N. C.; Muscatello, C. M. [University of California at Davis, Davis, California 95616 (United States); Classen, I. G. J. [Dutch Institute for Fundamental Fusion Energy Research, DIFFER, Rhinjuizen (Netherlands); Fitzpatrick, R. [University of Texas at Austin, Austin, Texas 78705 (United States); Olofsson, K. E. J.; Paz-Soldan, C. [General Atomics, San Diego, California 92121 (United States)

    2016-05-15

    The electromagnetic coupling of helical modes, even those having different toroidal mode numbers, modifies the distribution of toroidal angular momentum in tokamak discharges. This can have deleterious effects on other transport channels as well as on magnetohydrodynamic (MHD) stability and disruptivity. At low levels of externally injected momentum, the coupling of core-localized modes initiates a chain of events, whereby flattening of the core rotation profile inside successive rational surfaces leads to the onset of a large m/n = 2/1 tearing mode and locked-mode disruption. With increased torque from neutral beam injection, neoclassical tearing modes in the core may phase-lock to each other without locking to external fields or structures that are stationary in the laboratory frame. The dynamic processes observed in these cases are in general agreement with theory, and detailed diagnosis allows for momentum transport analysis to be performed, revealing a significant torque density that peaks near the 2/1 rational surface. However, as the coupled rational surfaces are brought closer together by reducing q{sub 95}, additional momentum transport in excess of that required to attain a phase-locked state is sometimes observed. Rather than maintaining zero differential rotation (as is predicted to be dynamically stable by single-fluid, resistive MHD theory), these discharges develop hollow toroidal plasma fluid rotation profiles with reversed plasma flow shear in the region between the m/n = 3/2 and 2/1 islands. The additional forces expressed in this state are not readily accounted for, and therefore, analysis of these data highlights the impact of mode coupling on torque balance and the challenges associated with predicting the rotation dynamics of a fusion reactor—a key issue for ITER.

  5. Flow cytometric assessment of microbial abundance in the near-field area of seawater reverse osmosis concentrate discharge

    KAUST Repository

    Van Der Merwe, Riaan

    2014-06-01

    The discharge of concentrate and other process waters from seawater reverse osmosis (SWRO) plant operations into the marine environment may adversely affect water quality in the near-field area surrounding the outfall. The main concerns are the increase in salt concentration in receiving waters, which results in a density increase and potential water stratification near the outfall, and possible increases in turbidity, e.g., due to the discharge of filter backwash waters. Changes in ambient water quality may affect microbial abundance in the area, for example by hindering the photosynthesis process or disrupting biogenesis. It is widely accepted that marine biodiversity is lower in more extreme conditions, such as high salinity environments. As aquatic microbial communities respond very rapidly to changes in their environment, they can be used as indicators for monitoring ambient water quality. The objective of this study was to assess possible changes in microbial abundance as a result of concentrate discharge into the near-field area (<. 25. m) surrounding the outfall of the King Abdullah University of Science and Technology (KAUST) SWRO plant. Flow cytometric (FCM) analysis was conducted in order to rapidly determine microbial abundance on a single-cell level in 107 samples, taken by diving, from the discharge area, the intake area and two control sites. FCM analysis combined the measurement of distinct scatter of cells and particles, autofluorescence of cyanobacteria and algae, and fluorescence after staining of nucleic acids with SYBR® Green for a total bacterial count. The results indicate that changes in microbial abundance in the near-field area of the KAUST SWRO outfall are minor and appear to be the result of a dilution effect rather than a direct impact of the concentrate discharge. © 2014 Elsevier B.V.

  6. Flow cytometric assessment of microbial abundance in the near-field area of seawater reverse osmosis concentrate discharge

    KAUST Repository

    Van Der Merwe, Riaan; Hammes, Frederik A.; Lattemann, Sabine; Amy, Gary L.

    2014-01-01

    The discharge of concentrate and other process waters from seawater reverse osmosis (SWRO) plant operations into the marine environment may adversely affect water quality in the near-field area surrounding the outfall. The main concerns

  7. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  8. Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack

    KAUST Repository

    Hatzell, Marta C.; Logan, Bruce E.

    2013-01-01

    ) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were

  9. Amazon river flow regime and flood recessional agriculture: Flood stage reversals and risk of annual crop loss

    Science.gov (United States)

    Coomes, Oliver T.; Lapointe, Michel; Templeton, Michael; List, Geneva

    2016-08-01

    The annual flood cycle is an important driver of ecosystem structure and function in large tropical rivers such as the Amazon. Riparian peasant communities rely on river fishing and annual floodplain agriculture, closely adapted to the recession phase of the flood pulse. This article reports on a poorly documented but important challenge facing farmers practicing flood recessional agriculture along the Amazon river: frequent, unpredictable stage reversals (repiquetes) which threaten to ruin crops growing on channel bars. We assess the severity of stage reversals for rice production on exposed river mud bars (barreales) near Iquitos, Peru. Crop loss risk is estimated based on a quantitative analysis of 45 years of daily Amazon stage data and field data from floodplain communities nearby in the Muyuy archipelago, upstream of Iquitos. Rice varieties selected, elevations of silt rich bars where rice is sown, as well as planting and harvest dates are analyzed in the light of the timing, frequencies and amplitudes of observed stage reversals that have the potential to destroy growing rice. We find that unpredictable stage reversals can produce substantial crop losses and shorten significantly the length of average growing seasons on lower elevation river bars. The data reveal that local famers extend planting down to lower bar elevations where the mean probabilities of re-submergence before rice maturity (due to reversals) approach 50%, below which they implicitly consider that the risk of crop loss outweighs the potential reward of planting.

  10. Directional change during a Miocene R-N geomagnetic polarity reversal recorded by mafic lava flows, Sheep Creek Range, north central Nevada, USA

    Science.gov (United States)

    Bogue, S. W.; Glen, J. M. G.; Jarboe, N. A.

    2017-09-01

    Recurring transitional field directions during three Miocene geomagnetic reversals provide evidence that lateral inhomogeneity of the lower mantle affects flow in the outer core. We compare new paleomagnetic results from a composite sequence of 15.2 Ma lava flows in north central Nevada (Sheep Creek Range; 40.7°N, 243.2°E), erupted during a polarity reversal, to published data from Steens Mountain (250 km to the northwest in Oregon) and the Newberry Mountains (650 km to the south in California) that document reversals occurring millions of years and many polarity switches earlier. Alternating field demagnetization, followed by thermal demagnetization in half the samples, clearly isolated the primary thermoremanent magnetization of Sheep Creek Range flows. We correlated results from our three sampled sections to produce a composite record that begins with a single virtual geomagnetic pole (VGP) at low latitude in the Atlantic, followed by two VGPs situated near latitude 30°N in NE Africa. After jumping to 83°N (one VGP), the pole moves to equatorial South America (one VGP), back to NE Africa (three VGPs), to high southern latitudes (two VGPs), back to equatorial South America (three VGPs), and finally to high northern latitudes (nine VGPs). The repeated visits of the transitional VGP to positions in South America and near NE Africa, as well as the similar behavior recorded at Steens Mountain and the Newberry Mountains, suggest that lower mantle or core-mantle boundary features localize core flow structures, thereby imparting a discernible regional structure on the transitional geomagnetic field that persists for millions of years.

  11. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  12. Large eddy simulation of premixed and non-premixed combustion in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Undapalli, Satish

    A new combustor referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet the increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high stability in both premixed and non-premixed modes. The objective of this thesis work is to perform Large Eddy Simulations (LES) on this lab-scale combustor and elucidate the underlying physics that has resulted in its excellent performance. To achieve this, numerical simulations have been performed in both the premixed and non-premixed combustion modes, and velocity field, species field, entrainment characteristics, flame structure, emissions, and mixing characteristics have been analyzed. Simulations have been carried out first for a non-reactive case to resolve relevant fluid mechanics without heat release by the computational grid. The computed mean and RMS quantities in the non-reacting case compared well with the experimental data. Next, the simulations were extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures: Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Results from the EBU and TF models exhibit reasonable agreement with the experimental velocity field. However, the computed thermal and species fields have noticeable discrepancies. Only LEM with LES (LEMLES), which is an advanced scalar approach, has been able to accurately predict both the velocity and species fields. Scalar mixing plays an important role in combustion, and this is solved directly at the sub-grid scales in LEM. As a result, LEM accurately predicts the scalar fields. Due to the two way coupling between the super-grid and sub-grid quantities, the velocity predictions also compare very well with the experiments. In other approaches, the sub-grid effects have been either modeled using conventional approaches (EBU) or need

  13. An extension of theoretical analysis for the onset of slugging criterion in horizontal stratified air-water countercurrent flow

    International Nuclear Information System (INIS)

    Lee, Byung Ryung

    1997-02-01

    This paper presents an experimental and theoretical investigation of interfacial friction factor, wave height and transition criterion from wavy to slug flow in a long horizontal air-water countercurrent stratified flow condition. A series of experiments have been conducted in adiabatic countercurrent stratified flow with the round pipe and rectangular duct test section to develop the interfacial friction factor and the criterion of onset of slugging in horizontal air-water countercurrent stratified flow. An adiabatic semi-empirical correlation for interfacial friction factor has been developed based on the surface roughness concept. A comparison of the measured data in this study and of other investigators with the predictions of the present correlation shows that the agreement is within ±30% error, and that the present correlation is applicable to a broader range of water flow rate than the correlations of previous investigators. The theories which can calculate the wave height and criteria of onset of slug flow in a stratified wavy flow regime have been developed based on the concept of total energy conservation and also wave theory. This theoretical criteria agree better with the measured data than the other criteria available in the literature, but the criteria range about 92∼107% of the measured data. An empirical formula for the criterion has been also developed and compared with the formula in the literatures. Comparison between the measured data and the predictions of the present theory shows that the agreement is within ±8%

  14. Energy consumption in membrane capacitive deionization for different water recoveries and flow rates, and comparison with reverse osmosis

    NARCIS (Netherlands)

    Zhao, R.; Porada, S.; Biesheuvel, P.M.; Wal, van der A.

    2013-01-01

    Membrane capacitive deionization (MCDI) is a non-faradaic, capacitive technique for desalinating brackish water by adsorbing ions in charged porous electrodes. To compete with reverse osmosis, the specific energy consumption of MCDI needs to be reduced to less than 1 kWh per m3 of freshwater

  15. Extensive investigation of the sap flow of maize plants in an oasis farmland in the middle reach of the Heihe River, Northwest China.

    Science.gov (United States)

    Zhao, Liwen; He, Zhibin; Zhao, Wenzhi; Yang, Qiyue

    2016-09-01

    A better understanding of the sap flow characteristics of maize plants is critical for improving irrigation water-use efficiency, especially for regions facing water resource shortages. In this study, sap flow rates, related soil-physics and plant-growth parameters, and meteorological factors, were simultaneously monitored in a maize field in two consecutive years, 2011 and 2012, and the sap flow rates of the maize plants were extensively analyzed based on the monitored data. Seasonal and daily variational characteristics were identified at different growth stages and under different weather conditions, respectively. The analyses on the relationships between sap flow rate and reference evapotranspiration (ET0), as well as several plant-growth parameters, indicate that the irrigation schedule can exert an influence on sap flow, and can consequently affect crop yield. The ranking of the main meteorological factors affecting the sap flow rate was: net radiation > air temperature > vapor pressure deficit > wind speed. For a quick estimation of sap flow rates, an empirical formula based on the two top influencing factors was put forward and verified to be reliable. The sap flow rate appeared to show little response to irrigation when the water content was relatively high, implying that some of the irrigation in recent years may have been wasted. These results may help to reveal the bio-physical processes of maize plants related to plant transpiration, which could be beneficial for establishing an efficient irrigation management system in this region and also for providing a reference for other maize-planting regions.

  16. Non-unique turbulent boundary layer flows having a moderately large velocity defect: a rational extension of the classical asymptotic theory

    Science.gov (United States)

    Scheichl, B.; Kluwick, A.

    2013-11-01

    The classical analysis of turbulent boundary layers in the limit of large Reynolds number Re is characterised by an asymptotically small velocity defect with respect to the external irrotational flow. As an extension of the classical theory, it is shown in the present work that the defect may become moderately large and, in the most general case, independent of Re but still remain small compared to the external streamwise velocity for non-zero pressure gradient boundary layers. That wake-type flow turns out to be characterised by large values of the Rotta-Clauser parameter, serving as an appropriate measure for the defect and hence as a second perturbation parameter besides Re. Most important, it is demonstrated that also this case can be addressed by rigorous asymptotic analysis, which is essentially independent of the choice of a specific Reynolds stress closure. As a salient result of this procedure, transition from the classical small defect to a pronounced wake flow is found to be accompanied by quasi-equilibrium flow, described by a distinguished limit that involves the wall shear stress. This situation is associated with double-valued solutions of the boundary layer equations and an unconventional weak Re-dependence of the external bulk flow—a phenomenon seen to agree well with previous semi-empirical studies and early experimental observations. Numerical computations of the boundary layer flow for various values of Re reproduce these analytical findings with satisfactory agreement.

  17. Retrospective study of irinotecan/cisplatin followed by etoposide/cisplatin or the reverse sequence in extensive-stage small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Xiao XG

    2015-08-01

    Full Text Available Xiaoguang Xiao, Shujing Wang, Shu Xia, Man Zou, Yang Li, Yao Wei, Qi Mei, Yuan Chen Department of Oncology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, People’s Republic of China Background: Much research has confirmed the favorable effect of irinotecan/cisplatin (IP and etoposide/cisplatin (EP on extensive-stage small cell lung cancer (E-SCLC. This study investigated two sequential orders of IP and EP in the treatment of E-SCLC. We also compared the efficacy and safety of IP and EP in first-line chemotherapy in E-SCLC. Methods: Ninety-three untreated patients with E-SCLC were randomly allocated to two groups. Group A received IP as first-line therapy until progression and then changed to EP; group B received EP as first-line therapy until tumor progression followed by IP. The primary endpoints were overall survival and time to second tumor progression. The secondary endpoints were first progression-free survival (PFS, ie, time from randomization to first occurrence of tumor progression after first-line treatment with IP or EP, tumor response, and safety of the different sequential treatment orders of IP and EP. Results: Median overall survival was 15.4 months in group A (IP followed by EP versus 15.7 months in group B (EP followed by IP; P=0.483. The median time to second tumor progression was 9.5 months in group A versus 9.9 months in group B (P=0.361. As first-line and second-line therapy, IP achieved a 95.9% and 60% disease control rate, respectively, and EP achieved 95.6% and 59% disease control rate. The median first PFS was not significantly different between group A and group B (6.5 months and 6.3 months, respectively; P=0.256. Grade 3/4 diarrhea appeared to be significantly more frequent with IP than with EP. The probability of anemia and thrombocytopenia was not significantly different between the two groups. However, significantly more patients who received the IP regimen as

  18. Improvement of the MSG code for the MONJU evaporators. Additional function of reverse flow calculation on water/steam model and animation for post processing

    International Nuclear Information System (INIS)

    Toda, Shin-ichi; Yoshikawa, Shinji; Oketani, Kazuhiro

    2003-05-01

    The improved version of the MSG code (Multi-dimensional Thermal-hydraulic Analysis Code for Steam Generators) has been released. It has been carried out to improve based on the original version in order to calculate reverse flow on water/steam side, and to animate the post-processing data. To calculate reverse flow locally, modification to set pressure at each divided node point of water/steam region in the helical-coil heat transfer tubes has been carried out. And the matrix solver has been also improved to treat a problem within practical calculation time against increasing the pressure points. In this case pressure and enthalpy have to be calculated simultaneously, however, it was found out that using the block-Jacobean method make a diagonal-dominant matrix, and solve the matrix efficiently with a relaxation method. As the result of calculations of a steady-state condition and a transient of SG blow down with manual trip operation, the improvement on calculation function of the MSG code was confirmed. And an animation function of temperature contour in the sodium shell side as a post processing has been added. Since the animation is very effective to understand thermal-hydraulic behavior on the sodium shell side of the SG, especially in case of transient condition, the analysis and evaluation of the calculation results will be enabled to be more quickly and effectively. (author)

  19. A validation of LTRAN2 with high frequency extensions by comparisons with experimental measurements of unsteady transonic flows

    Science.gov (United States)

    Hessenius, K. A.; Goorjian, P. M.

    1981-01-01

    A high frequency extension of the unsteady, transonic code LTRAN2 was created and is evaluated by comparisons with experimental results. The experimental test case is a NACA 64A010 airfoil in pitching motion at a Mach number of 0.8 over a range of reduced frequencies. Comparisons indicate that the modified code is an improvement of the original LTRAN2 and provides closer agreement with experimental lift and moment coefficients. A discussion of the code modifications, which involve the addition of high frequency terms of the boundary conditions of the numerical algorithm, is included.

  20. Impact characteristics for high-pressure large-flow water-based emulsion pilot operated check valve reverse opening

    Science.gov (United States)

    Liu, Lei; Huang, Chuanhui; Yu, Ping; Zhang, Lei

    2017-10-01

    To improve the dynamic characteristics and cavitation characteristics of large-flow pilot operated check valve, consider the pilot poppet as the research object, analyses working principle and design three different kinds of pilot poppets. The vibration characteristics and impact characteristics are analyzed. The simulation model is established through flow field simulation software. The cavitation characteristics of large-flow pilot operated check valve are studied and discussed. On this basis, high-pressure large-flow impact experimental system is used for impact experiment, and the cavitation index is discussed. Then optimal structure is obtained. Simulation results indicate that the increase of pilot poppet half cone angle can effectively reduce the cavitation area, reducing the generation of cavitation. Experimental results show that the pressure impact is not decreasing with increasing of pilot poppet half cone angle in process of unloading, but the unloading capacity, response speed and pilot poppet half cone angle are positively correlated. The impact characteristics of 60° pilot poppet, and its cavitation index is lesser, which indicates 60° pilot poppet is the optimal structure, with the theory results are basically identical.

  1. Extension of the flow-rate-of-strain tensor formulation of plasma rotation theory to non-axisymmetric tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Bae, C. [National Fusion Research Institute, Daejoen (Korea, Republic of)

    2015-06-15

    A systematic formalism for the calculation of rotation in non-axisymmetric tokamaks with 3D magnetic fields is described. The Braginskii Ωτ-ordered viscous stress tensor formalism, generalized to accommodate non-axisymmetric 3D magnetic fields in general toroidal flux surface geometry, and the resulting fluid moment equations provide a systematic formalism for the calculation of toroidal and poloidal rotation and radial ion flow in tokamaks in the presence of various non-axisymmetric “neoclassical toroidal viscosity” mechanisms. The relation among rotation velocities, radial ion particle flux, ion orbit loss, and radial electric field is discussed, and the possibility of controlling these quantities by producing externally controllable toroidal and/or poloidal currents in the edge plasma for this purpose is suggested for future investigation.

  2. Radiometric and paleomagnetic evidence for the Emperor reversed polarity event at 0.46 ± 0.05 M.Y. in basalt lava flows from the eastern Snake River Plain, Idaho

    Science.gov (United States)

    Champion, Duane E.; Dalrymple, G. Brent; Kuntz, Mel A.

    1981-01-01

    K-Ar and paleomagnetic data from cores through a sequence of basalt flows in the eastern Snake River Plain provide evidence for a brief (0.005 to 0.01 m.y.) reversal of the geomagnetic field 0.46 ± 0.05 m.y. ago. This reversed polarity event has also been found in sea-floor magnetic anomalies and in sediment cores and is probably the Emperor event of Ryan [1972].

  3. Physicochemical attack against solid tumors based on the reversal of direction of entropy flow: an attempt to introduce thermodynamics in anticancer therapy

    Directory of Open Access Journals (Sweden)

    Lv Xiaogui

    2006-11-01

    tissues, the rate of entropy production of normal cells may exceed that of cancerous cells. Consequently, the application of external energy to the body can reverse the direction of the entropy current. The harmful effect brought about by the entropy flow from cancerous to healthy tissue can be blocked by the reversed direction of entropy current from the irradiated normal tissue around the tumor.

  4. Reverse Algols

    Science.gov (United States)

    Leung, K. C.

    1989-01-01

    Reverse Algols, binary systems with a semidetached configuration in which the more massive component is in contact with the critical equipotential surface, are examined. Observational evidence for reverse Algols is presented and the parameters of seven reverse Algols are listed. The evolution of Algols and reverse Algols is discussed. It is suggested that, because reverse Algols represent the premass-reversal semidetached phase of close binary evolution, the evolutionary time scale between regular and reverse Algols is the ratio of the number of confirmed systems of these two Algol types.

  5. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  6. Application of NEA/CSNI standard problem 3 (blowdown and flow reversal in the IETA-1 rig) to the validation of the RELAP-UK Mk IV code

    International Nuclear Information System (INIS)

    Bryce, W.M.

    1977-10-01

    NEA/CSNI Standard Problem 3 consists of the modelling of an experiment on the IETI-1 rig, in which there is initially flow upwards through a feeder, heated section and riser. The inlet and outlet are then closed and a breach opened at the bottom so that the flow reverses and the rig depressurises. Calculations of this problem by many countries using several computer codes have been reported and show a wide spread of results. The purpose of the study reported here was the following. First, to show the sensitivity of the calculation of Standard Problem 3. Second, to perform an ab initio best estimate calculation using the RELAP-UK Mark IV code with the standard recommended options, and third, to use the results of the sensitivity study to show where tuning of the RELAP-UK Mark IV recommended model options was required. This study has shown that the calculation of Standard Problem 3 is sensitive to model assumptions and that the use of the loss-of-coolant accident code RELAP-UK Mk IV with the standard recommended model options predicts the experimental results very well over most of the transient. (U.K.)

  7. Tuning the Stability of Organic Active Materials for Nonaqueous Redox Flow Batteries via Reversible, Electrochemically Mediated Li + Coordination

    Energy Technology Data Exchange (ETDEWEB)

    Carino, Emily V.; Staszak-Jirkovsky, Jakub; Assary, Rajeev S.; Curtiss, Larry A.; Markovic, Nenad M.; Brushett, Fikile R.

    2016-03-24

    We describe an electrochemically mediated interaction between Li+ and a promising active material for nonaqueous redox flow batteries (RFBs), 1,2,3,4-tetrahydro-6,7-dimethoxy-1,1,4,4-tetramethylnaphthalene (TDT), and the impact of this structural interaction on material stability during voltammetric cycling. TDT could be an advantageous organic positive electrolyte material for nonaqueous RFBs due to its high oxidation potential, 4.21 V vs Li/Li+, and solubility of at least 1.0 M in select electrolytes. Although results from voltammetry suggest TDT displays Nernstian reversibility in many nonaqueous electrolyte solutions, bulk electrolysis reveals significant degradation in all electrolytes studied, the extent of which depends on the electrolyte solution composition. Results of subtractively normalized in situ Fourier transform infrared spectroscopy (SNIFTIRS) confirm that TDT undergoes reversible structural changes during cyclic voltammetry in propylene carbonate and 1,2-dimethoxyethane solutions containing Li+ electrolytes, but irreversible degradation occurs when tetrabutylammonium (TBA+) replaces Li+ as the electrolyte cation in these solutions. By combining the results from SNIFTIRS experiments with calculations from density functional theory, solution-phase active species structure and potential-dependent interactions can be determined. We find that Li+ coordinates to the Lewis basic methoxy groups of neutral TDT and, upon electrochemical oxidation, this complex dissociates into the radical cation TDT•+ and Li+. The improved cycling stability in the presence of Li+ relative to TBA+ suggests that the structural interaction reported herein may be advantageous to the design of energy storage materials based on organic molecules.

  8. Reverse Osmosis

    Indian Academy of Sciences (India)

    many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van 't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis. Osmosis and Reverse Osmosis. As the name suggests, reverse osmosis is the ...

  9. Application of computer code ALMOD in transient analysis with reverse flow in the primary loop of nuclear power plant; Primjena programa ALMOD u analizi prijelaznih pojava sa reverzibilnim protokom u primarnom krugu nuklerne elektrane

    Energy Technology Data Exchange (ETDEWEB)

    Bencik, V [Elektrotehnicki Institut ' Rade Koncar' , Zagreb (Yugoslavia); Feretic, D; Debrecin, N [Elektrotehnicki fakultet, Zagreb (Yugoslavia)

    1989-07-01

    A computer code ALMOD 3W3 to analyze the transients in which reverse flow in the primary loop of nuclear power plant may occur has been developed. The method to calculate the fluid dynamics in NRC system is presented. The locked rotor accident in one coolant loop is analyzed. (author)

  10. Does Deccan Volcanic Sequence contain more reversals than the three-Chron N-R-N flow magnetostratigraphy?- A paleomagnetic evidence from the dyke-swarm near Mumbai

    Science.gov (United States)

    Basavaiah, N.; Satyanarayana, KVV; Deenadayalan, K.; Prasad, JN

    2018-02-01

    New paleomagnetic data from a series of Deccan-age dykes cutting across the basement of lava flows along east and south of Mumbai (18°-19° N and 72°-73.5° E) have uncovered both normal (N) and reverse (R) magnetizations. Out of 33 dykes investigated, 29 dykes have yielded stable characteristic remanent magnetizations (ChRM) amenable for statistical analysis. Twenty dykes exhibit N-polarity and nine dykes show R-polarity. The tilt-corrected dyke VGPs reveal two distinct groups of dykes. Each group consists of both N- and R- polarity dykes on the Indian Apparent Polar Wander Path (APWP). The mean of N-polarity dykes is antipodal to the mean of R-polarity dykes. Group I (GI) comprises nine N-polarity dykes with their mean at Dm = 337.8°, Im = -39.4° (k = 130.7, α95 = 4.5°), and three dykes of R-polarity whose mean is at Dm = 150.7°, Im = 44.1° (k = 147.1, α95 = 10.2°). The corresponding pole positions are at 43.5° S, 102.6° E (A95 = 4.6°) and 36.6° S, 107.6° E (A95 = 8.9°) respectively. These pole positions fall close to 65 Ma old Deccan Superpole (DSP) on the APWP, and may therefore be associated with magnetic Chron 29 N for the N-polarity and 29R for the R-polarity of the three-Chron (30N - 29R -29Ν) magnetostratigraphy of the Deccan Volcanic Province (DVP) used in the computation of DSP. In Group II (GII), eleven dykes display N-polarity with mean at Dm = 312.6°, Im = -45.2° (k = 93.3, α95 = 4.8°) and six dykes show R-polarity with mean at Dm = 130.1°, Im = 48.0° (k = 176.8, α95 = 5.1°). The corresponding pole positions at 25° S, 120.1° E (A95 = 5.3°) and 22.2° S, 119.1° E (A95 = 5.2°) respectively are significantly displaced (by more than 20°) from the DSP along the older segment (˜80 -90 Ma) of the Indian APWP. Hence, the dykes of GII appear to have been emplaced in an earlier episodic Deccan activity than that represented by the DSP. The paleolatituides corresponding to GI and GII are 23.2° S ± 4.0 and 27.6° S ± 4

  11. Manual and Flow-Injection Detection/Quantification of Polyquaterniums via Fully Reversible Polyion-Sensitive Polymeric Membrane-Based Ion-Selective Electrodes.

    Science.gov (United States)

    Ferguson, Stephen A; Meyerhoff, Mark E

    2017-10-27

    The detection of four different polyquaterniums (PQs) using a fully reversible potentiometric polyion sensor in three different detection modes is described. The polyion sensing "pulstrodes" serve as the detector for direct dose-response experiments, beaker titrations, and in a flow-injection analysis (FIA) system. Direct polycation response toward PQ-2, PQ-6, PQ-10, and poly(2-methacryloxyethyltrimethylammonium) chloride (PMETAC) yields characteristic information about each PQ species (e.g., relative charge densities, etc.) via syringe pump addition of each PQ species to a background electrolyte solution. Quantitative titrations are performed using a syringe pump to deliver heparin as the polyanion titrant to quantify all four PQs at μg/mL levels. Both the direct and indirect methods incorporate the use of a three-electrode system including counter, double junction reference, and working electrodes. The working electrode possesses a plasticized poly(vinyl chloride) (PVC) membrane containing the neutral lipophilic salt of dinonylnaphthalenesulfonate (DNNS - ) tridodecylmethylammonium (TDMA + ). Further, the titration method is shown to be useful to quantify PQ-6 levels in recreational swimming pool water collected in Ann Arbor, MI. Finally, a FIA system equipped with a pulstrode detector is used to demonstrate the ability to potentially quantify PQ levels via a more streamlined and semiautomated testing platform.

  12. Visual detection of West Nile virus using reverse transcription loop-mediated isothermal amplification combined with a vertical flow visualization strip

    Directory of Open Access Journals (Sweden)

    Zengguo eCao

    2016-04-01

    Full Text Available West Nile virus (WNV causes a severe zoonosis, which can lead to a large number of casualties and considerable economic losses. A rapid and accurate identification methodfor WNV for use in field laboratories is urgently needed. Here, a method utilizing reverse transcription loop-mediated isothermal amplification combined with a vertical flow visualization strip (RT-LAMP-VF was developed to detect the envelope (E gene of WNV. The RT-LAMP-VF assay could detect 102 copies/μl ofan WNV RNA standard using a 40 min amplification reaction followed by a 2 min incubationof the amplification product on the visualization strip, and no cross-reaction with other closely related members of theFlavivirus genus was observed. The assay was further evaluated using cells and mouse brain tissues infected with a recombinant rabies virus expressing the E protein of WNV.The assay produced sensitivities of 101.5TCID50/ml and 101.33 TCID50/ml for detection of the recombinant virus in the cells and brain tissues, respectively. Overall, the RT-LAMP-VF assay developed in this study is rapid, simple and effective, and it is therefore suitable for clinical application in the field.

  13. Management of small-for-gestational-age twins with absent/reversed end diastolic flow in the umbilical artery: outcome of a policy of daily biophysical profile (BPP).

    Science.gov (United States)

    Kennelly, Máiréad M; Sturgiss, Stephen N

    2007-01-01

    To evaluate a strategy of daily biophysical profile (BPP) for pregnancies with small-for-gestational-age twins and with absent or reversed end diastolic flow (AREDF) in the umbilical artery of one twin and to assess the latency interval between detection and delivery in monochorionic (MC) and dichorionic (DC) twin pregnancy. A search of the Fetal Medicine Database was carried out between 2000 and 2005 at a single tertiary centre to identify all cases with AREDF in the umbilical artery with one small-for-gestational-age twin. Active monitoring with daily BPP was undertaken, once the estimated fetal weights (EFW) was >or= 500 g and at a gestational age of >or= 24 weeks in both twins. Delivery was timed on the basis of an abnormal BPP, two equivocal BPP within 12 h or gestational age of >or= 32(+0) weeks. Twenty-two MC and 17 DC twin pregnancies were identified. There were no fetal losses in the viable actively monitored MC (19) and DC (13) twins. There was a longer latency interval in the MC group at 21.7 days versus 14.4 days in the DC group (p = 0.13). Delivery was indicated for an abnormal BPP (57.8% MC vs 30.8% DC). A strategy of daily BPP can be used to monitor preterm twin fetuses with AREDF, prolonging pregnancy with an acceptable perinatal outcome. Copyright 2007 John Wiley & Sons, Ltd.

  14. Reversible inactivation and excitation of nucleus raphe magnus can modulate tail blood flow of male Wistar rats in response to hypothermia.

    Science.gov (United States)

    Malakouti, Seyed Mansour; Kourosh Arami, Masoomeh; Sarihi, Abdorahman; Hajizadeh, Sohrab; Behzadi, Gila; Shahidi, Siamak; Komaki, Alireza; Heshmatian, Behnam; Vahabian, Mehrangiz

    2008-10-01

    The nucleus raphe magnus (NRM) is involved in thermoregulatory processing. There is a correlation between changes in the firing rates of the cells in the NRM and the application of the peripheral thermal stimulus. we examined the effect of reversible inactivation and excitation of NRM on mechanisms involved in tail blood flow (TBF) regulation in hypothermia. Hypothermia was induced in Male Wistar rats and cannula was implanted above the NRM. To evaluate the effect of nucleus inactivation on TBF, the amount of TBF was measured by Laser Doppler in hypothermic rats, before and after lidocaine microinjection into NRM. TBF was also measured after glutamate microinjection to assess the effect of nucleus excitation in hypothermic rats. Results indicated that after dropping TBF by hypothermia, microinjection of lidocaine into NRM significantly decreased TBF from 54.43 +- 5.7 to 46.81 +- 3.4, whereas glutamate microinjection caused a significant increase from 44.194 +- 0.6 to 98 +- 10.0 CONCLUSION: These data suggest that NRM have thermoregulatory effect in response to hypothermia.

  15. A functional language for describing reversible logic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    Reversible logic is a computational model where all gates are logically reversible and combined in circuits such that no values are lost or duplicated. This paper presents a novel functional language that is designed to describe only reversible logic circuits. The language includes high....... Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...... circuits. The flow relies on a reversible combinator language as an intermediate language....

  16. SELECTED PROBLEMS OF REVERSE LOGISTICS IN POLAND

    OpenAIRE

    Agata Mesjasz-Lech

    2009-01-01

    This paper presents the essence of reverse logistics and directions of physical and information flows between logistic network partners. It also analyses effects of implementation of the principles of reverse logistics in Poland in the years 2004-2007

  17. Detection of viable cortical neurons using benzodiazepine receptor imaging after reversible focal ischaemia in rats: comparison with regional cerebral blood flow

    International Nuclear Information System (INIS)

    Watanabe, Yoshiyuki; Nakano, Takayuki; Yutani, Kenji; Nishimura, Hiroshi; Nishimura, Tsunehiko; Kusuoka, Hideo; Nakamura, Hironobu

    2000-01-01

    To elucidate the utility of benzodiazepine receptor imaging for the detection of viable cortical neurons, dual-tracer autoradiography using iodine-125 iomazenil (IMZ) and iodine-123 N-isopropyl-4-iodoamphetamine (IMP) was performed in a model of reversible focal ischaemia during the acute and subacute phases. The right middle cerebral artery of anaesthetized rats was occluded for 60 min using an intraluminal filament and reperfused. In the acute phase study, 125 I-IMZ (370 kBq) was injected via the femoral vein at 2 h after reperfusion, and 123 I-IMP (37 MBq) was injected at 50 min post-injection. Rats were sacrificed 10 min after the injection of 123 I-IMP. In the subacute phase study, the same procedure was performed at 5 days after reperfusion. In the acute phase, the IMP uptake was significantly decreased in almost all areas of the lesioned hemisphere, an exception being the cerebellum; however, the IMZ uptake was significantly decreased only in ischaemic cores. The discrepancy between IMZ and IMP uptake was observed in the lateral neocortex and the lateral caudate putamen (CPu), which were most frequently damaged in this ischaemic model. In the subacute phase, the IMZ uptake in lesioned rats was significantly decreased only in the parietal lobe and hippocampus, though the IMP uptake was decreased in many regions of lesioned hemispheres (the frontal, parietal cortex, CPu, hippocampus and thalamus). Histopathological findings indicated that both the IMP and the IMZ uptake was markedly decreased in necrotic areas. Although the IMP uptake was significantly decreased in the ischaemic areas, the IMZ uptake was maintained in these areas. These results suggest that benzodiazepine receptor imaging is superior to regional cerebral blood flow imaging for the detection of viable cortical neurons in both the acute and subacute phases of ischaemia. (orig.)

  18. Study of the influence of surfactants on the activity coefficients and mass transfer coefficients of methanol in aqueous mixtures by reversed-flow gas chromatography.

    Science.gov (United States)

    Kotsalos, Efthimios; Brezovska, Boryana; Sevastos, Dimitrios; Vagena, Artemis; Koliadima, Athanasia; Kapolos, John; Karaiskakis, George

    2017-11-17

    This work focuses on the influences of surfactants on the activity coefficients, γ, of methanol in binary mixtures with water, as well as on the mass transfer coefficients, k c , for the evaporation of methanol, which is a ubiquitous component in the troposphere, from mixtures of methanol with water at various surfactant's and methanol's concentrations. The technique used is the Reversed-Flow Gas Chromatography (R.F.G.C.), a version of Inverse Gas Chromatography, which allows determining both parameters by performing only one experiment for the k c parameter and two experiments for the γ parameter. The k c and γ values decrease in the presence of the three surfactants used (CTAB, SDS, TRITON X-100) at all methanol's and surfactant's concentrations. The decrease in the methanol's molar fraction, at constant number of surfactant films leads to a decrease in the k c and γ values, while the decrease in the surfactant's concentration, at constant methanol's molar fraction leads to an increase in both the k c and γ parameters. Mass transfer coefficients for the evaporation of methanol at the surfactant films, are also calculated which are approximately between 4 and 5 orders of magnitude larger than the corresponding mass transfer coefficients at the liquid films. Finally, thicknesses of the boundary layer of methanol in the mixtures of methanol with water were determined. The quantities found are compared with those given in the literature or calculated theoretically using various empirical equations. The precision of the R.F.G.C. method for measuring γ and k c parameters is approximately high (94.3-98.0%), showing that R.F.G.C. can be used with success not only for the thermodynamic study of solutions, but also for the interphase transport. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Detection of viable cortical neurons using benzodiazepine receptor imaging after reversible focal ischaemia in rats: comparison with regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshiyuki [Dept. of Radiology, Osaka National Hospital (Japan); Nakano, Takayuki; Yutani, Kenji; Nishimura, Hiroshi; Nishimura, Tsunehiko [Div. of Tracer Kinetics, Osaka University Medical School (Japan); Kusuoka, Hideo [Clinical Research Institute, Osaka National Hospital (Japan); Nakamura, Hironobu [Dept. of Radiology, Osaka University Medical School (Japan)

    2000-03-01

    To elucidate the utility of benzodiazepine receptor imaging for the detection of viable cortical neurons, dual-tracer autoradiography using iodine-125 iomazenil (IMZ) and iodine-123 N-isopropyl-4-iodoamphetamine (IMP) was performed in a model of reversible focal ischaemia during the acute and subacute phases. The right middle cerebral artery of anaesthetized rats was occluded for 60 min using an intraluminal filament and reperfused. In the acute phase study, {sup 125}I-IMZ (370 kBq) was injected via the femoral vein at 2 h after reperfusion, and {sup 123}I-IMP (37 MBq) was injected at 50 min post-injection. Rats were sacrificed 10 min after the injection of {sup 123}I-IMP. In the subacute phase study, the same procedure was performed at 5 days after reperfusion. In the acute phase, the IMP uptake was significantly decreased in almost all areas of the lesioned hemisphere, an exception being the cerebellum; however, the IMZ uptake was significantly decreased only in ischaemic cores. The discrepancy between IMZ and IMP uptake was observed in the lateral neocortex and the lateral caudate putamen (CPu), which were most frequently damaged in this ischaemic model. In the subacute phase, the IMZ uptake in lesioned rats was significantly decreased only in the parietal lobe and hippocampus, though the IMP uptake was decreased in many regions of lesioned hemispheres (the frontal, parietal cortex, CPu, hippocampus and thalamus). Histopathological findings indicated that both the IMP and the IMZ uptake was markedly decreased in necrotic areas. Although the IMP uptake was significantly decreased in the ischaemic areas, the IMZ uptake was maintained in these areas. These results suggest that benzodiazepine receptor imaging is superior to regional cerebral blood flow imaging for the detection of viable cortical neurons in both the acute and subacute phases of ischaemia. (orig.)

  20. Extensive Mutagenesis of the Conserved Box E Motif in Duck Hepatitis B Virus P Protein Reveals Multiple Functions in Replication and a Common Structure with the Primer Grip in HIV-1 Reverse Transcriptase

    OpenAIRE

    Wang, Yong-Xiang; Luo, Cheng; Zhao, Dan; Beck, Jürgen; Nassal, Michael

    2012-01-01

    Hepadnaviruses, including the pathogenic hepatitis B virus (HBV), replicate their small DNA genomes through protein-primed reverse transcription, mediated by the terminal protein (TP) domain in their P proteins and an RNA stem-loop, ϵ, on the pregenomic RNA (pgRNA). No direct structural data are available for P proteins, but their reverse transcriptase (RT) domains contain motifs that are conserved in all RTs (box A to box G), implying a similar architecture; however, experimental support for...

  1. Effects of the proposed California WaterFix North Delta Diversion on flow reversals and entrainment of juvenile Chinook salmon (Oncorhynchus tshawytscha) into Georgiana Slough and the Delta Cross Channel, northern California

    Science.gov (United States)

    Perry, Russell W.; Romine, Jason G.; Pope, Adam C.; Evans, Scott D.

    2018-02-27

    The California Department of Water Resources and Bureau of Reclamation propose new water intake facilities on the Sacramento River in northern California that would convey some of the water for export to areas south of the Sacramento-San Joaquin River Delta (hereinafter referred to as the Delta) through tunnels rather than through the Delta. The collection of water intakes, tunnels, pumping facilities, associated structures, and proposed operations are collectively referred to as California WaterFix. The water intake facilities, hereinafter referred to as the North Delta Diversion (NDD), are proposed to be located on the Sacramento River downstream of the city of Sacramento and upstream of the first major river junction where Sutter Slough branches from the Sacramento River. The NDD can divert a maximum discharge of 9,000 cubic feet per second (ft3/s) from the Sacramento River, which reduces the amount of Sacramento River inflow into the Delta.In this report, we conducted three analyses to investigate the effect of the NDD and its proposed operation on entrainment of juvenile Chinook salmon (Oncorhynchus tshawytscha) into Georgiana Slough and the Delta Cross Channel (DCC). Fish that enter the interior Delta (the network of channels to the south of the Sacramento River) through Georgiana Slough and the DCC survive at lower rates than fish that use other migration routes (Sacramento River, Sutter Slough, and Steamboat Slough). Therefore, fisheries managers were concerned about the extent to which operation of the NDD would increase the proportion of the population entering the interior Delta, which, all else being equal, would lower overall survival through the Delta by increasing the fraction of the population subject to lower survival rates. Operation of the NDD would reduce flow in the Sacramento River, which has the potential to increase the magnitude and duration of reverse flows of the Sacramento River downstream of Georgiana Slough.In the first analysis, we

  2. Matching the reaction-diffusion simulation to dynamic [18F]FMISO PET measurements in tumors: extension to a flow-limited oxygen-dependent model.

    Science.gov (United States)

    Shi, Kuangyu; Bayer, Christine; Gaertner, Florian C; Astner, Sabrina T; Wilkens, Jan J; Nüsslin, Fridtjof; Vaupel, Peter; Ziegler, Sibylle I

    2017-02-01

    Positron-emission tomography (PET) with hypoxia specific tracers provides a noninvasive method to assess the tumor oxygenation status. Reaction-diffusion models have advantages in revealing the quantitative relation between in vivo imaging and the tumor microenvironment. However, there is no quantitative comparison of the simulation results with the real PET measurements yet. The lack of experimental support hampers further applications of computational simulation models. This study aims to compare the simulation results with a preclinical [ 18 F]FMISO PET study and to optimize the reaction-diffusion model accordingly. Nude mice with xenografted human squamous cell carcinomas (CAL33) were investigated with a 2 h dynamic [ 18 F]FMISO PET followed by immunofluorescence staining using the hypoxia marker pimonidazole and the endothelium marker CD 31. A large data pool of tumor time-activity curves (TAC) was simulated for each mouse by feeding the arterial input function (AIF) extracted from experiments into the model with different configurations of the tumor microenvironment. A measured TAC was considered to match a simulated TAC when the difference metric was below a certain, noise-dependent threshold. As an extension to the well-established Kelly model, a flow-limited oxygen-dependent (FLOD) model was developed to improve the matching between measurements and simulations. The matching rate between the simulated TACs of the Kelly model and the mouse PET data ranged from 0 to 28.1% (on average 9.8%). By modifying the Kelly model to an FLOD model, the matching rate between the simulation and the PET measurements could be improved to 41.2-84.8% (on average 64.4%). Using a simulation data pool and a matching strategy, we were able to compare the simulated temporal course of dynamic PET with in vivo measurements. By modifying the Kelly model to a FLOD model, the computational simulation was able to approach the dynamic [ 18 F]FMISO measurements in the investigated

  3. Criterion for selection of quasi-equilibrium and quasi-frozen flows of chemically reacting mixture N2O4 reversible 2NO2reversible 2NO+O2 with heat isobaric supply (removal)

    International Nuclear Information System (INIS)

    Kostik, G.Eh.; Shiryaeva, N.M.

    1979-01-01

    Is suggested the criterion of quasi-equilibrium and quasi-frozen flows with isobaric heat supply (removal), including the basic external factors, which affect on the kinetics of chemical process. This criterion is the complex [g/Fq], where g is the coolant rate, F is the channel cross-section, q is the heat flow. Estimated formulae for quasi-equilibrium [g/Fq]sub(e) and quasi-frozen [g/Fq]sub(f) flows are obtained. The states of deviation from equilibrium and frozen conditions in linear region are considered, are listed graphical dependences lg[g/Fq]sub(e), lg[g/Fq]sub(el), lg[g/Fq]sub(f), lg[g/Eq]sub(fl), as functions of equilibrium parameter Tsub(e), pressure and frozen coordinate of epsilonsub(2f) reaction. This graphs give the possibility to estimate rapidly and obviously the flow character of chemically reacting coolant

  4. Six-flow operations for catalyst development in Fischer-Tropsch synthesis : Bridging the gap between high-throughput experimentation and extensive product evaluation

    NARCIS (Netherlands)

    Sartipi, S.; Jansma, H.; Bosma, D.; Boshuizen, B.; Makkee, M.; Gascon, J.; Kapteijn, F.

    2013-01-01

    Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature

  5. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Janusz K. Grabara; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  6. Combining or Separating Forward and Reverse Logistics

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel; Nielsen, Anders

    2018-01-01

    Purpose – While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine reverse logistics with forward logistics, keep the flows separated, or choose......-research addresses intra-RL issues while the relationship between forward and reverse logistics is under-researched. This paper contributes to RL-theory by identifying the contextual factors that determine the most advantageous relationship between forward and reverse logistics, and proposes a novel decision making...

  7. Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

    OpenAIRE

    Sartipi, S.; Jansma, H.; Bosma, D.; Boshuizen, B.; Makkee, M.; Gascon, J.; Kapteijn, F.

    2013-01-01

    Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controllers, assuring an identical isothermal zone of at least 10 cm along six fixed-bed microreactor inserts (4?mm inner diameter). Such a lab-scale setup allows running six experiments in parallel, under...

  8. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions......’s portfolio of global innovation competence and capability. The implications for management are concerned with internal and external resistance to reverse innovation. Most significantly, while greater recognition and power of innovation in formerly subordinate organizational units is inconvenient to some...

  9. Evaluation of Cytokine Synthesis in Human Whole Blood by Enzyme Linked Immunoassay (ELISA), Reverse Transcriptase Polymerase Chain Reaction (RT-PCR), and Flow Cytometry

    Science.gov (United States)

    2007-05-08

    deoxynucleotide triphosphates, from Sigma. Sequences for glyceraldehyde-3-phosphate dehydrogenase ( G3PDH ), IL-8,and TNF-a were amplified with primer...This was accomplished by normalizing all samples to the mRNA for the moderately expressed housekeeping function glyceraldehyde-3 -phosphate...without and with isolation of cells before reverse transcription and PCR. G3PDH mRNA target amplifies at 983 base pairs. The 630 base pair band is the

  10. Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Sartipi, Sina, E-mail: S.Sartipi@tudelft.nl, E-mail: J.Gascon@tudelft.nl; Jansma, Harrie; Bosma, Duco; Boshuizen, Bart; Makkee, Michiel; Gascon, Jorge, E-mail: S.Sartipi@tudelft.nl, E-mail: J.Gascon@tudelft.nl; Kapteijn, Freek [Department of Chemical Engineering, Catalysis Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands)

    2013-12-15

    Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controllers, assuring an identical isothermal zone of at least 10 cm along six fixed-bed microreactor inserts (4 mm inner diameter). Such a lab-scale setup allows running six experiments in parallel, under equal feed composition, reaction temperature, and conditions of separation and analysis equipment. It permits separate collection of wax and liquid samples (from each flow line), allowing operation with high productivities of C5+ hydrocarbons. The latter is crucial for a complete understanding of FTS product compositions and will represent an advantage over high-throughput setups with more than ten flows where such instrumental considerations lead to elevated equipment volume, cost, and operation complexity. The identical performance (of the six flows) under similar reaction conditions was assured by testing a same catalyst batch, loaded in all microreactors.

  11. Six-flow operations for catalyst development in Fischer-Tropsch synthesis: Bridging the gap between high-throughput experimentation and extensive product evaluation

    International Nuclear Information System (INIS)

    Sartipi, Sina; Jansma, Harrie; Bosma, Duco; Boshuizen, Bart; Makkee, Michiel; Gascon, Jorge; Kapteijn, Freek

    2013-01-01

    Design and operation of a “six-flow fixed-bed microreactor” setup for Fischer-Tropsch synthesis (FTS) is described. The unit consists of feed and mixing, flow division, reaction, separation, and analysis sections. The reactor system is made of five heating blocks with individual temperature controllers, assuring an identical isothermal zone of at least 10 cm along six fixed-bed microreactor inserts (4 mm inner diameter). Such a lab-scale setup allows running six experiments in parallel, under equal feed composition, reaction temperature, and conditions of separation and analysis equipment. It permits separate collection of wax and liquid samples (from each flow line), allowing operation with high productivities of C5+ hydrocarbons. The latter is crucial for a complete understanding of FTS product compositions and will represent an advantage over high-throughput setups with more than ten flows where such instrumental considerations lead to elevated equipment volume, cost, and operation complexity. The identical performance (of the six flows) under similar reaction conditions was assured by testing a same catalyst batch, loaded in all microreactors

  12. Optimization of memory use of fragment extension-based protein-ligand docking with an original fast minimum cost flow algorithm.

    Science.gov (United States)

    Yanagisawa, Keisuke; Komine, Shunta; Kubota, Rikuto; Ohue, Masahito; Akiyama, Yutaka

    2018-03-16

    The need to accelerate large-scale protein-ligand docking in virtual screening against a huge compound database led researchers to propose a strategy that entails memorizing the evaluation result of the partial structure of a compound and reusing it to evaluate other compounds. However, the previous method required frequent disk accesses, resulting in insufficient acceleration. Thus, more efficient memory usage can be expected to lead to further acceleration, and optimal memory usage could be achieved by solving the minimum cost flow problem. In this research, we propose a fast algorithm for the minimum cost flow problem utilizing the characteristics of the graph generated for this problem as constraints. The proposed algorithm, which optimized memory usage, was approximately seven times faster compared to existing minimum cost flow algorithms. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...... language and a high-level structured language. We introduce concrete tools such as program inverters and translators for both languages, which follow the structure suggested by the flowchart model. To further illustrate the different concepts and tools brought together in this paper, we present two major...

  14. Ash-flow tuff distribution and fault patterns as indicators of rotation of late-tertiary regional extension, Nevada test site

    International Nuclear Information System (INIS)

    Ander, H.D.

    1983-01-01

    Isopach and structure contour maps generated for Yucca Flat as well as fault pattern analyses of the Nevada Test Site (NTS) can aid in more efficient site selection and site characterization necessary for containment. Furthermore, these geologic studies indicate that most of the alluvial deposition in Yucca Flat was controlled by north-trending faults responding to a regional extension direction oriented approximately 20 0 to 30 0 west of the N50 0 W direction observed today. The Yucca Flat basin-forming Carpetbag and Yucca fault systems seem to be deflected at their southern ends into the northeast-trending Cane Spring and Mine Mountain fault systems. Left-lateral strike-slip displacement of approx. 1.4 km found on these northeasterly faults requires that most of the displacement on the combined fault systems occurred in an extension field oriented approximately N80 0 W. Fault movement in this extensional field postdates the Ammonia Tanks tuff (approx. 11 My) and was strongly active during deposition of some 1100 meters of alluvium in Yucca Flat. Time of rotation of regional extension to the presently active N50 0 W direction is unknown; however, it occurred so recently that it has not greatly modified fault displacement patterns extant at the NTS

  15. Magnetohydrodynamic and thermal radiation effects on the boundary-layer flow due to a moving extensible surface with the velocity slip model: A comparative study of four nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Emad H., E-mail: efarag@uj.edu.sa [Department of Mathematics, Faculty of Science, University of Jeddah, Jeddah 21589 (Saudi Arabia); Department of Mathematics, Faculty of Education, Ain Shams University, Roxy, Cairo 11757 (Egypt); Sayed, Hamed M. [Department of Mathematics, Faculty of Education, Ain Shams University, Roxy, Cairo 11757 (Egypt); Department of Mathematics, Faculty of Sciences, Taibah University, Yanbu (Saudi Arabia)

    2017-01-15

    In the current work, we investigated effects of the velocity slip for the flow and heat transfer of four nanofluids over a non-linear stretching sheet taking into account the thermal radiation and magnetic field in presence of the effective electrical conductivity. The governing partial differential equations were transformed into a set of nonlinear ordinary differential equation using similarity transformations before being solved numerically by the Chebyshev pseudospectral differentiation matrix (ChPDM). It was found that the investigated parameters affect remarkably on the nanofluid stream function for the whole investigated nanoparticles. In addition, velocity and skin friction profiles of the four investigated nanofluids decreases and increases, respectively, with the increase of the magnetic parameter, first-order and second-order velocity slips. Further, the flow velocity, surface shear stress and temperature are strongly influenced on applying the velocity slip model, where lower values of the second-order imply higher surface heat flux and thereby making the fluid warmer. - Highlights: • A comparative study for four nanoparticles with MHD and thermal radiation effects was studied. • The effective electrical conductivity is mandatory; otherwise a spurious physical sight will be gained. • The investigated parameters affect remarkably on the nanofluids' flow. • The flow velocity, surface shear stress and temperature are strongly influenced by the slip model. • Lower values of the second-order imply higher surface heat flux and thereby making the fluid warmer.

  16. An experimental study on the negative effects of downwards flow of the melted frost over a multi-circuit outdoor coil in an air source heat pump during reverse cycle defrosting

    International Nuclear Information System (INIS)

    Song, Mengjie; Pan, Dongmei; Li, Ning; Deng, Shiming

    2015-01-01

    Highlights: • A special experimental rig was built and its details are reported. • The negative effects of downwards flowing of the melted frost were shown. • Defrosting duration was shortened after installing water collecting trays. • Temperature of melted frost decreased after installing trays. - Abstract: When the surface temperature of the outdoor coil in an air source heat pump (ASHP) unit is lower than both freezing point of water and the air dew point, frost can be formed and accumulated over outdoor coil surface. Frosting affects the energy efficiency, and periodic defrosting therefore is necessary. Reverse cycle defrosting is currently the most widely used defrosting method. A previous related study has indicated that during reverse cycle defrosting, downwards flow of the melted frost over a multi-circuit outdoor coil could affect the defrosting performance, without however giving detailed quantitative analysis of the effects. Therefore an experimental study on the effects has been carried out and a quantitative analysis conducted using the experimental data. In this paper, the detailed description of an experimental ASHP unit which was specifically built up is firstly reported. This is followed by presenting experimental results. Result analysis and conclusions are finally given

  17. Radial flow in non-extensive thermodynamics and study of particle spectra at LHC in the limit of small (q - 1)

    International Nuclear Information System (INIS)

    Bhattacharyya, Trambak; Khuntia, Arvind; Pareek, Pooja; Sahoo, Raghunath; Cleymans, Jean

    2016-01-01

    We expand the Tsallis distribution in a Taylor series of powers of (q - 1), where q is the Tsallis parameter, assuming q is very close to 1. This helps in studying the degree of deviation of transverse momentum spectra and other thermodynamic quantities from a thermalized Boltzmann distribution. After checking thermodynamic consistency, we provide analytical results for the Tsallis distribution in the presence of collective flow up to the first order of (q - 1). The formulae are compared with the experimental data. (orig.)

  18. Radial flow in non-extensive thermodynamics and study of particle spectra at LHC in the limit of small (q - 1)

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, Trambak; Khuntia, Arvind; Pareek, Pooja; Sahoo, Raghunath [Indian Institute of Technology Indore, Discipline of Physics, School of Basic Sciences, Simrol (India); Cleymans, Jean [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Rondebosch (South Africa)

    2016-02-15

    We expand the Tsallis distribution in a Taylor series of powers of (q - 1), where q is the Tsallis parameter, assuming q is very close to 1. This helps in studying the degree of deviation of transverse momentum spectra and other thermodynamic quantities from a thermalized Boltzmann distribution. After checking thermodynamic consistency, we provide analytical results for the Tsallis distribution in the presence of collective flow up to the first order of (q - 1). The formulae are compared with the experimental data. (orig.)

  19. Extension of a semi-implicit shock-capturing algorithm for 3-D fully coupled, chemically reacting flows in generalized coordinates

    International Nuclear Information System (INIS)

    Shinn, J.L.; Yee, H.C.; Uenishi, K.; NASA, Ames Research Center, Moffett Field, CA; Vigyan Research Associates, Inc., Hampton, VA)

    1987-01-01

    A semiimplicit high-resolution shock-capturing method for multidimensional systems of hyperbolic conservation laws with stiff source terms has been developed by Yee and Shinn (1987). The goal of this work is to extend this method to solve the three-dimensional fully coupled Navier-Stokes equations for a hypersonic chemically reacting flow in generalized coordinates. In this formulation, the global continuity equation was replaced by all the species continuity equations. The shock-capturing technique is a second-order-accurate, symmetric total-variation-diminishing method which accounts fully and directly for the coupling among the fluid and all the species. To verify the current approach, it was implemented into an existing computer code which contained the MacCormack method. Test results for a five-species reacting flow are shown to be oscillation-free around the shock, and the time spent per iteration only doubles when compared to the result using classical way of supplying numerical dissipation. The extra computation is more than justified by the elimination of spurious oscillation and nonlinear instability associated with the classical shock-capturing schemes in computing hypersonic reacting flows. 27 references

  20. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  1. Reversible infantile mitochondrial diseases.

    Science.gov (United States)

    Boczonadi, Veronika; Bansagi, Boglarka; Horvath, Rita

    2015-05-01

    Mitochondrial diseases are usually severe and progressive conditions; however, there are rare forms that show remarkable spontaneous recoveries. Two homoplasmic mitochondrial tRNA mutations (m.14674T>C/G in mt-tRNA(Glu)) have been reported to cause severe infantile mitochondrial myopathy in the first months of life. If these patients survive the first year of life by extensive life-sustaining measures they usually recover and develop normally. Another mitochondrial disease due to deficiency of the 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) causes severe liver failure in infancy, but similar to the reversible mitochondrial myopathy, within the first year of life these infants may also recover completely. Partial recovery has been noted in some other rare forms of mitochondrial disease due to deficiency of mitochondrial tRNA synthetases and mitochondrial tRNA modifying enzymes. Here we summarize the clinical presentation of these unique reversible mitochondrial diseases and discuss potential molecular mechanisms behind the reversibility. Understanding these mechanisms may provide the key to treatments of potential broader relevance in mitochondrial disease, where for the majority of the patients no effective treatment is currently available.

  2. An investigation of scramming the outer shutdown rods of the ANS with no reversal of flow in the manifold inlet lines

    International Nuclear Information System (INIS)

    Morsk, K.

    1992-10-01

    This report provides calculations and calculation checks on the outer shutdown system, consisting of eight shutdown rods located on the outside of the core. The function of the system is to scram the reactor, or to break the chain reaction of the fission process. The shutdown rods are clad with a neutron-absorbing material (i.e., hafnium) to achieve scram. During normal operation, the outer shutdown rods (Fig. 1) are in a nonscram, withdrawn position. This means that they are not close enough to the core to absorb a significant number of the neutrons that cause the fission process. In the case of a malfunction or an emergency, the outer control rods are moved to a position near the core. The outer shutdown system is operated with the use of springs and hydraulics. During normal operation, a constant flow of heavy water is circulated through the reflector vessel. A part of this flow provides a pressure high enough to keep the rods in their withdrawn or upper position, a nonscram status. If any signs of abnormal operation occur, the valves in the hydraulic system cut off the flow, and the springs push the rods into the scram position, stopping the chain reaction. Once the flow is restarted, the rods can be withdrawn to the nonscram position. Calculations of the mass of the outer control rod, the scram spring data, and the hydraulic pressure to hold the rods in the withdrawn position have been checked. In the case of a malfunction of the flow/pressure relief valves, a calculation was needed to show that the scram time would not exceed the time allowed. The scram time has been determined based on different values of the rod insertion length and the outside radius of the annulus was calculated. The effective force pushing the rod into the scram position, the rate of acceleration, and the actual scram time was then determined

  3. Anticommutative extension of the Adler map

    Science.gov (United States)

    Konstantinou-Rizos, S.; Mikhailov, A. V.

    2016-07-01

    We construct a noncommutative (Grassmann) extension of the well-known Adler Yang-Baxter map. It satisfies the Yang-Baxter equation, it is reversible and birational. Our extension preserves all the properties of the original map except the involutivity.

  4. Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

    International Nuclear Information System (INIS)

    Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

    1980-01-01

    Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

  5. Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

    International Nuclear Information System (INIS)

    Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

    1980-01-01

    Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are dramatically improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

  6. END-OF-USE PRODUCTS IN REVERSE LOGISTICS

    OpenAIRE

    Marta Starostka-Patyk

    2007-01-01

    Reverse logistics is a very useful tool for enterprises which have to deal with end-of-use products. Forward logistics is not able to manage them, because they show up on the beginning of reverse supply chain. That is the reason for growing importance of reverse flows. Reverse logistics is quite new logistics system. This paper presents the idea of reverse logistics and end-of-use products problems.

  7. Flow regimes

    International Nuclear Information System (INIS)

    Kh'yuitt, G.

    1980-01-01

    An introduction into the problem of two-phase flows is presented. Flow regimes arizing in two-phase flows are described, and classification of these regimes is given. Structures of vertical and horizontal two-phase flows and a method of their identification using regime maps are considered. The limits of this method application are discussed. The flooding phenomena and phenomena of direction change (flow reversal) of the flow and interrelation of these phenomena as well as transitions from slug regime to churn one and from churn one to annular one in vertical flows are described. Problems of phase transitions and equilibrium are discussed. Flow regimes in tubes where evaporating liquid is running, are described [ru

  8. Reverse osmosis application studies

    International Nuclear Information System (INIS)

    Golomb, A.

    1982-02-01

    To assess the feasibility of applying reverse osmosis (RO) and ultrafiltration (UF) for effective treatment of process and waste streams from operations at Ontario Hydro's thermal and nuclear stations, an extensive literature survey has been carried out. It is concluded that RO is not at present economic for pretreatment of Great Lakes water prior to ion exchange demineralization for boiler makeup. Using both conventional and novel commercial membrane modules, RO pilot studies are recommended for treatment of boiler cleaning wastes, fly ash leachates, and flue gas desulphurization scrubber discharges for removal of heavy metals. Volume reduction and decontamination of nuclear station low-level active liquid waste streams by RO/UF also appear promising. Research programmes are proposed

  9. Renewable synthesis-gas-production. Do hydrocarbons in the reactant flow of the reverse water-gas shift reaction cause coke formation?

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, A.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    In a two-step synthetic fuel production process based on carbon dioxide and renewable hydrogen, the best possible selectivity towards liquid hydrocarbons (Hc) shall be implemented. The process consists of a combination of the Reverse Water-Gas Shift reaction and the Fischer-Tropsch synthesis. To achieve this goal, gaseous short-chained Hc from the FTS reactor are recycled in the RWGS unit. In this paper, challenges coming up with the implementation of a recycle loop are discussed. First of all, it has to be examined whether Hc are converted under conditions present in the RWGS reactor. The coking caused by the recycle of Hc is regarded, including thermal coking in the heating zone of the reactor and catalytic coking in the catalyst bed. Coking of course is unwanted, as it deactivates the catalyst. The scope of this work is to find out to which extent and under which conditions gaseous Hc can be recycled. Therefore, experiments were carried out in both, a quartz glass reactor using a commercial Ni-catalyst at ambient pressure and in a pressurized steel reactor (without catalyst) to examine coking during the thermal decomposition of Hc. The catalytic experiments at atmospheric pressure showed that a recycle of CH{sub 4} did not cause coking up to a ratio of CH{sub 4}/CO{sub 2} below one. For these conditions, long term stability was proved. The reaction rates of the CH{sub 4} conversion were below those of the RWGS reaction. However, replacing CH{sub 4} by C{sub 3}H{sub 8} leads to thermal and catalytic coking. Catalytic coking hits the maximum level at about 700 C and decreases for higher temperatures and, thus is not regarded as a problem for the RWGS reactor. In contrast to that, thermal coking raises with higher temperatures, but it can be supressed efficiently with additional injection of H{sub 2}O, which of course shifts the equilibrium towards the undesired reactant side. (orig.)

  10. Reversible flow of cholesteryl ester between high-density lipoproteins and triacylglycerol-rich particles is modulated by the fatty acid composition and concentration of triacylglycerols

    Directory of Open Access Journals (Sweden)

    E.C.R. Quintão

    2010-12-01

    Full Text Available We determined the influence of fasting (FAST and feeding (FED on cholesteryl ester (CE flow between high-density lipoproteins (HDL and plasma apoB-lipoprotein and triacylglycerol (TG-rich emulsions (EM prepared with TG-fatty acids (FAs. TG-FAs of varying chain lengths and degrees of unsaturation were tested in the presence of a plasma fraction at d > 1.21 g/mL as the source of CE transfer protein. The transfer of CE from HDL to FED was greater than to FAST TG-rich acceptor lipoproteins, 18% and 14%, respectively. However, percent CE transfer from HDL to apoB-containing lipoproteins was similar for FED and FAST HDL. The CE transfer from HDL to EM depended on the EM TG-FA chain length. Furthermore, the chain length of the monounsaturated TG-containing EM showed a significant positive correlation of the CE transfer from HDL to EM (r = 0.81, P < 0.0001 and a negative correlation from EM to HDL (r = -041, P = 0.0088. Regarding the degree of EM TG-FAs unsaturation, among EMs containing C18, the CE transfer was lower from HDL to C18:2 compared to C18:1 and C18:3, 17.7%, 20.7%, and 20%, respectively. However, the CE transfer from EMs to HDL was higher to C18:2 than to C18:1 and C18:3, 83.7%, 51.2%, and 46.3%, respectively. Thus, the EM FA composition was found to be the rate-limiting factor regulating the transfer of CE from HDL. Consequently, the net transfer of CE between HDL and TG-rich particles depends on the specific arrangement of the TG acyl chains in the lipoprotein particle core.

  11. Reverse logistics in the Brazilian construction industry.

    Science.gov (United States)

    Nunes, K R A; Mahler, C F; Valle, R A

    2009-09-01

    In Brazil most Construction and Demolition Waste (C&D waste) is not recycled. This situation is expected to change significantly, since new federal regulations oblige municipalities to create and implement sustainable C&D waste management plans which assign an important role to recycling activities. The recycling organizational network and its flows and components are fundamental to C&D waste recycling feasibility. Organizational networks, flows and components involve reverse logistics. The aim of this work is to introduce the concepts of reverse logistics and reverse distribution channel networks and to study the Brazilian C&D waste case.

  12. Scintigraphic characteristics of experimental myocardial infarct extension

    International Nuclear Information System (INIS)

    Kronenberg, M.W.; Wooten, N.E.; Friesinger, G.C.; Page, D.L.; Higgins, S.B.; Collins, J.C.; O'Connor, J.L.; Price, R.R.; Brill, A.B.

    1979-01-01

    Technetium-99m-stannous pyrophosphate scintiphotos were evaluated for diagnosing and quantitating myocardial infarct (MI) extension in sedated dogs. Infarction and extension were produced by serial left anterior descending coronary artery ligations at 0 and 48 hours. We compared serial scintiphoto data with regional myocardial blood flow (MBF) (microsphere technique) and infarct histopathology. In eight control dogs, the scintigraphic MI area was stable at 24, 48, and 72 hours. In each of 11 dogs undergoing extension, the MI area increased after the 48-hour occlusion, averaging a 48.9% increase (p < 0.001). Grossly, most extensions were mixtures of confluent necrosis and moderate (patchy) necrosis. MBF to confluent infarct tissue decreased significantly, allowing the documentation of extension by totaling the grams of newly flow-deprived tissue, but patchy infarct tissue had little flow deprivation, making it difficult to quantitate this type of extension accurately by flow criteria alone. Rarely, extension could be diagnosed using conventional histologic criteria. We concluded that the scintiphoto MI area was related quantitatively to infarct weight in both control and extension. However, it was not possible to determine that an increase in the MI scintiphoto area was an accurate predictor of the degree of extension using independent flow or pathologic criteria

  13. Reverse innovation in maternal health.

    Science.gov (United States)

    Firoz, Tabassum; Makanga, Prestige Tatenda; Nathan, Hannah L; Payne, Beth; Magee, Laura A

    2017-09-01

    Reverse innovation, defined as the flow of ideas from low- to high-income settings, is gaining traction in healthcare. With an increasing focus on value, investing in low-cost but effective and innovative solutions can be of mutual benefit to both high- and low-income countries. Reverse innovation has a role in addressing maternal health challenges in high-income countries by harnessing these innovative solutions for vulnerable populations especially in rural and remote regions. In this paper, we present three examples of 'reverse innovation' for maternal health: a low-cost, easy-to-use blood pressure device (CRADLE), a diagnostic algorithm (mini PIERS) and accompanying mobile app (PIERS on the Move), and a novel method for mapping maternal outcomes (MOM).

  14. The Role of IT Solutions in Reverse Logistics Management Support

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... Keywords-reverse logistics, return flow, IT solutions, EDI, Barcodes, ... and controlling the efficiency, performance, cost flow of raw materials ..... questions, for the further analysis only these were chosen that are strongly ...

  15. Does Deccan Volcanic Sequence contain more reversals than the three-Chron N-R-N flow magnetostratigraphy?—a palaeomagnetic evidence from the dyke-swarm near Mumbai

    Science.gov (United States)

    Basavaiah, N.; Satyanarayana, K. VV; Deenadayalan, K.; Prasad, J. N.

    2018-06-01

    New palaeomagnetic data from a series of Deccan-age dykes cutting across the basement of lava flows along east and south of Mumbai (18°-19°N and 72°-73.5°E) have uncovered both normal (N) and reverse (R) magnetizations. Out of 33 dykes investigated, 29 dykes have yielded stable characteristic remanent magnetizations (ChRM) amenable for statistical analysis. Twenty dykes exhibit N-polarity and nine dykes show R-polarity. The tilt-corrected dyke virtual geomagnetic poles reveal two distinct groups of dykes. Each group consists of both N- and R-polarity dykes on the Indian apparent polar wander path (APWP). The mean of N-polarity dykes is antipodal to the mean of R-polarity dykes. Group I (GI) comprises nine N-polarity dykes with their mean at Dm = 337.8°, Im = -39.4° (k = 130.7, α95 = 4.5°), and three dykes of R-polarity whose mean is at Dm = 150.7°, Im = 44.1° (k = 147.1, α95 = 10.2°). The corresponding pole positions are at 43.5°S, 102.6°E (A95 = 4.6°) and 36.6°S, 107.6°E (A95 = 8.9°) respectively. These pole positions fall close to 65 Ma old Deccan Superpole (DSP) on the APWP, and may therefore be associated with magnetic Chron 29N for the N-polarity and 29R for the R-polarity of the three-Chron (30N-29R-29Ν) magnetostratigraphy of the Deccan Volcanic Province (DVP) used in the computation of DSP. In Group II (GII), eleven dykes display N-polarity with mean at Dm = 312.6°, Im = -45.2° (k = 93.3, α95 = 4.8°) and six dykes show R-polarity with mean at Dm = 130.1°, Im = 48.0° (k = 176.8, α95 = 5.1°). The corresponding pole positions at 25°S, 120.1°E (A95 = 5.3°) and 22.2°S, 119.1°E (A95 = 5.2°) respectively are significantly displaced (by more than 20°) from the DSP along the older segment (˜80-90 Ma) of the Indian APWP. Hence, the dykes of GII appear to have been emplaced in an earlier episodic Deccan activity than that represented by the DSP. The palaeolatituides corresponding to GI and GII are 23.2°S ± 4.0 and 27.6°S ± 4

  16. Batteryless photovoltaic reverse-osmosis desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, M.; Miranda, M.; Gwillim, J.; Rowbottom, A.; Draisey, I.

    2001-07-01

    The aim of this project was to design an efficient cost-effective batteryless photovoltaic-powered seawater reverse-osmosis desalination system, to deliver in the order of 3 m{sup 3} of fresh drinking water per day. The desalination of seawater to produce fresh drinking water is extremely valuable on islands and in coastal regions wherever natural freshwater is scarce. Existing small-scale desalination equipment, suitable for areas of medium and low population density, often requires a copious and constant supply of energy, either electricity or diesel. If supply of these fuels is expensive or insecure, but the area has a good solar resource, the use of photovoltaic power is an attractive option. Existing demonstrations of photovoltaic-powered desalination generally employ lead-acid batteries, which allow the equipment to operate at a constant flow, but are notoriously problematic in practice. The system developed in this project runs at variable flow, enabling it to make efficient use of the naturally varying solar resource, without need of batteries. In a sense, the freshwater tank is providing the energy storage. In this project, we have reviewed the merits of a wide variety of reverse-osmosis system configurations and component options. We have completed extensive in-house testing and characterisation of major hardware components and used the results to construct detailed software models. Using these, we have designed a system that meets the above project aim, and we have predicted its performance in detail. Our designs show that a system costing 23,055 pounds stirling will produce 1424 m{sup 3} of fresh drinking water annually - an average of just over 3.9 m{sup 3}/day. The system has no fuel costs and no batteries. The overall cost of water, including full maintenance, is 2.00 pounds stirling per m{sup 3}. The energy consumption (photovoltaic-electricity) is typically between 3.2 and 3.7 kWh/m{sup 3} depending on the solar irradiance and feed water

  17. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2013-12-01

    Full Text Available As the power of consumers is growing, the product return for customer service and customer retention has become a common practice in the competitive market, which propels the recent practice of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle. Reverse logistics is the flow and management of products, packaging, components and information from the point of consumption to the point of origin. It is a collection of practices similar to those of supply chain management, but in the opposite direction, from downstream to upstream. It involves activities such as reuse, repair, remanufacture, refurbish, reclaim and recycle. For the conventional forward logistics systems, the flow starts upstream as raw materials, later as manufactured parts and components to be assembled and continues downstream to reach customers as final products to be disposed once they reach their economic or useful lives. In reverse logistics, the disposed products are pushed upstream to be repaired, remanufactured, refurbished, and disassembled into components to be reused or as raw material to be recycled for later use.

  18. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won; Song, Chang Joon; Song, Soon-Young; Koo, Ja Hong; Kim, Man Deuk

    2001-01-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  19. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  20. Sociologists in Extension

    Science.gov (United States)

    Christenson, James A.; And Others

    1977-01-01

    The article describes the work activities of the extension sociologist, the relative advantage and disadvantage of extension roles in relation to teaching/research roles, and the relevance of sociological training and research for extension work. (NQ)

  1. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  2. Tubal Ligation Reversal

    Science.gov (United States)

    ... seal off the fallopian tubes, such as the Essure or Adiana systems, generally aren't reversible. Why ... electrocautery). Some types of sterilization, such as the Essure or Adiana systems, aren't considered reversible. Risks ...

  3. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  4. Rapid and sensitive detection of novel avian-origin influenza A (H7N9 virus by reverse transcription loop-mediated isothermal amplification combined with a lateral-flow device.

    Directory of Open Access Journals (Sweden)

    Yiyue Ge

    Full Text Available A severe disease in humans caused by a novel avian-origin influenza A (H7N9 virus emerged in China recently, which has caused at least 128 cases and 26 deaths. Rapid detection of the novel H7N9 virus is urgently needed to differentiate the disease from other infections, and to facilitate infection control as well as epidemiologic investigations. In this study, a reverse transcription loop-mediated isothermal amplification combined with a lateral flow device (RT-LAMP-LFD assay to rapidly detect H7N9 virus was developed and evaluated. The RT-LAMP primers were designed to target the haemagglutinin (HA and neuraminidase (NA genes of H7N9 virus. Results of 10-fold dilution series assays showed that analysis of RT-LAMP products by the LFD method was as sensitive as real-time turbidity detection, and that the analytic sensitivities of the HA and NA RT-LAMP assays were both 10 copies of synthetic RNA. Furthermore, both the assays showed 100% clinical specificity for identification of H7N9 virus. The performance characteristics of the RT-LAMP-LFD assay were evaluated with 80 clinical specimens collected from suspected H7N9 patients. The NA RT-LAMP-LFD assay was more sensitive than real time RT-PCR assay. Compared with a combination of virus culture and real-time RT-PCR, the sensitivity, specificity, positive predictive value, and negative predictive value of the RT-LAMP-LFD assay were all 100%. Overall, The RT-LAMP-LFD assay established in this study can be used as a reliable method for early diagnosis of the avian-origin influenza A (H7N9 virus infection.

  5. Preliminary validation of direct detection of foot-and-mouth disease virus within clinical samples using reverse transcription loop-mediated isothermal amplification coupled with a simple lateral flow device for detection.

    Directory of Open Access Journals (Sweden)

    Ryan A Waters

    Full Text Available Rapid, field-based diagnostic assays are desirable tools for the control of foot-and-mouth disease (FMD. Current approaches involve either; 1 Detection of FMD virus (FMDV with immuochromatographic antigen lateral flow devices (LFD, which have relatively low analytical sensitivity, or 2 portable RT-qPCR that has high analytical sensitivity but is expensive. Loop-mediated isothermal amplification (LAMP may provide a platform upon which to develop field based assays without these drawbacks. The objective of this study was to modify an FMDV-specific reverse transcription-LAMP (RT-LAMP assay to enable detection of dual-labelled LAMP products with an LFD, and to evaluate simple sample processing protocols without nucleic acid extraction. The limit of detection of this assay was demonstrated to be equivalent to that of a laboratory based real-time RT-qPCR assay and to have a 10,000 fold higher analytical sensitivity than the FMDV-specific antigen LFD currently used in the field. Importantly, this study demonstrated that FMDV RNA could be detected from epithelial suspensions without the need for prior RNA extraction, utilising a rudimentary heat source for amplification. Once optimised, this RT-LAMP-LFD protocol was able to detect multiple serotypes from field epithelial samples, in addition to detecting FMDV in the air surrounding infected cattle, pigs and sheep, including pre-clinical detection. This study describes the development and evaluation of an assay format, which may be used as a future basis for rapid and low cost detection of FMDV. In addition it provides providing "proof of concept" for the future use of LAMP assays to tackle other challenging diagnostic scenarios encompassing veterinary and human health.

  6. End-shorting and electric field in edge plasmas with application to field-reversed configurations

    International Nuclear Information System (INIS)

    Steinhauer, Loren C.

    2002-01-01

    The shorting of open field lines where they intersect external boundaries strongly modifies the transverse electric field all along the field lines. The modified electric field is found by an extension of the familiar Boltzmann relation for the electric potential. This leads to a prediction of the electric drift. Flow generation by electrical shorting is applied here to three aspects of elongated field-reversed configurations: plasma rotation rate; the particle-loss spin-up mechanism; and the sustainability of the rotating magnetic field current drive method

  7. Multiple reversal olfactory learning in honeybees

    Directory of Open Access Journals (Sweden)

    Theo Mota

    2010-07-01

    Full Text Available In multiple reversal learning, animals trained to discriminate a reinforced from a non-reinforced stimulus are subjected to various, successive reversals of stimulus contingencies (e.g. A+ vs. B-, A- vs. B+, A+ vs. B-. This protocol is useful to determine whether or not animals learn to learn and solve successive discriminations faster (or with fewer errors with increasing reversal experience. Here we used the olfactory conditioning of proboscis extension reflex to study how honeybees Apis mellifera perform in a multiple reversal task. Our experiment contemplated four consecutive differential conditioning phases involving the same odors (A+ vs. B- to A- vs. B+ to A+ vs. B- to A- vs. B+. We show that bees in which the weight of reinforced or non-reinforced stimuli was similar mastered the multiple olfactory reversals. Bees which failed the task exhibited asymmetric responses to reinforced and non-reinforced stimuli, thus being unable to rapidly reverse stimulus contingencies. Efficient reversers did not improve their successive discriminations but rather tended to generalize their choice to both odors at the end of conditioning. As a consequence, both discrimination and reversal efficiency decreasedalong experimental phases. This result invalidates a learning-to-learn effect and indicates that bees do not only respond to the actual stimulus contingencies but rather combine these with an average of past experiences with the same stimuli.  

  8. Compound nucleus studies withy reverse kinematics

    International Nuclear Information System (INIS)

    Moretto, L.G.

    1985-06-01

    Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs

  9. Reverse osmosis water purification system

    Science.gov (United States)

    Ahlstrom, H. G.; Hames, P. S.; Menninger, F. J.

    1986-01-01

    A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water.

  10. The Forward-Reverse Algorithm for Stochastic Reaction Networks

    KAUST Repository

    Bayer, Christian; Moraes, Alvaro; Tempone, Raul; Vilanova, Pedro

    2015-01-01

    In this work, we present an extension of the forward-reverse algorithm by Bayer and Schoenmakers [2] to the context of stochastic reaction networks (SRNs). We then apply this bridge-generation technique to the statistical inference problem

  11. Hypertension as the trigger for posterior reversible encephalopathy ...

    African Journals Online (AJOL)

    RESEARCH. Posterior reversible encephalopathy syndrome (PRES) is a neuro ..... rise of blood pressure instead of the sustained levels of hypertension in these patients. .... high prevalence and more extensive imaging findings. Am J Kidney ...

  12. Magnetic reversals from planetary dynamo waves.

    Science.gov (United States)

    Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

    2016-11-24

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

  13. Plasma flow in the DIII-D divertor

    International Nuclear Information System (INIS)

    Boedo, J.A.; Porter, G.D.; Schaffer, M.J.

    1998-07-01

    Indications that flows in the divertor can exhibit complex behavior have been obtained from 2-D modeling but so far remain mostly unconfirmed by experiment. An important feature of flow physics is that of flow reversal. Flow reversal has been predicted analytically and it is expected when the ionization source arising from neutral or impurity ionization in the divertor region is large, creating a high pressure zone. Plasma flows arise to equilibrate the pressure. A radiative divertor regime has been proposed in order to reduce the heat and particle fluxes to the divertor target plates. In this regime, the energy and momentum of the plasma are dissipated into neutral gas introduced in the divertor region, cooling the plasma by collisional, radiative and other atomic processes so that the plasma becomes detached from the target plates. These regimes have been the subject of extensive studies in DIII-D to evaluate their energy and particle transport properties, but only recently it has been proposed that the energy transport over large regions of the divertor must be dominated by convection instead of conduction. It is therefore important to understand the role of the plasma conditions and geometry on determining the region of convection-dominated plasma in order to properly control the heat and particle fluxes to the target plates and hence, divertor performance. The authors have observed complex structures in the deuterium ion flows in the DIII-D divertor. Features observed include reverse flow, convective flow over a large volume of the divertor and stagnant flow. They have measured large gradients in the plasma potential across the separatrix in the divertor and determined that these gradients induce poloidal flows that can potentially affect the particle balance in the divertor

  14. Reverse-symmetry waveguides: Theory and fabrication

    DEFF Research Database (Denmark)

    Horvath, R.; Lindvold, Lars René; Larsen, N.B.

    2002-01-01

    We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractive...... index of the waveguide substrate less than the refractive index of the medium covering the waveguiding film (n(water) = 1.33). This is opposed to the conventional waveguide geometry, where the substrate is usually glass or polymers with refractive indices of approximate to1.5. The reverse configuration...... are combined with air-grooved polymer supports to form freestanding single-material polymer waveguides of reverse symmetry capable of guiding light....

  15. Corrosion protected reversing heat exchanger

    International Nuclear Information System (INIS)

    Zawierucha, R.

    1984-01-01

    A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

  16. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  17. The reversed-flow gas chromatography technique as a tool for the study of the evaporation retardation of SO2 and (CH3)2S from water by soluble surfactants.

    Science.gov (United States)

    Sevastos, D; Kotsalos, E; Koliadima, A

    2017-02-01

    In the present work the evaporation retardation of SO 2 and (CH 3 ) 2 S (=DMS) from water by soluble surfactants was studied by the Reversed-Flow Gas Chromatography (R.F.G.C.) technique. Using suitable mathematical analysis, rate coefficients, k c , for the transfer of SO 2 and DMS from pure or artificial sea water to the atmospheric environment were determined in the presence or the absence of surfactants. The efficiency of the three surfactants used (CTAB, TRITON X-100 and SDS) to retard the evaporation rate of SO 2 and DMS from water was estimated by the decrease of the k c values in the presence of the three surfactants, compared to those in the absence of surfactants. The more efficient surfactant for the retardation evaporation of SO 2 from both the pure and the artificial sea water was found to be the cationic CTAB surfactant, as the maximum decreases of the k c values were found to be 4.61×10 -3 cms -1 (number of films, n=1) and 3.07×10 -3 cms -1 (n=3), respectively. On the other hand, more efficient surfactant for the retardation evaporation of DMS from pure water was found to be the non-ionic TRITON X-100, in which the decrease of the k c value was estimated to be 18.20×10 -3 cms -1 (n=3) and from artificial sea water the cationic CTAB surfactant in which the decrease of the k c value was found to be 8.24×10 -3 cms -1 (n=3). Finally, the precision of the R.F.G.C. method in studying the retardation effect of various surfactants in the transfer of SO 2 and DMS from the water body to the atmosphere is estimated (mean value 96.69%), and the experimental values of k c are compared with those given in the literature. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Reversibility of female sterilization.

    Science.gov (United States)

    Siegler, A M; Hulka, J; Peretz, A

    1985-04-01

    The discussion considers the current status of reversibility of sterilization in the US and describes clinical and experimental efforts for developing techniques designed for reversibility. It focuses on regret following sterilization, reversal potential of current sterilization techniques, patient selection, current reversal techniques, results of sterilization procedures, experimental approaches to reversal of current techniques of sterilization, and sterilization procedures devised for reversibility, in humans and in animals. Request is the 1st stage of reversal, but a request for sterilization reversal (SR) does not always mean regret for a decision made at the time. Frequently it is a wish to restore fertility because life circumstances have changed after a sterilization that was ppropriate at the time it was performed. Schwyhart and Kutner reviewed 22 studies published between 1949-69 in which they found that the percentage of patients regretting the procedure ranged from 1.3-15%. Requests for reversal remain low in most countries, but if sterilization becomes a more popular method of contraception, requests will also increase. The ideal operation considered as a reversaible method of sterilization should include an easy, reliable outpatient method of tubal occlusion with miniml risk or patient discomfort that subsequently could be reversed without the need for a major surgical intervention. Endoscopic methods have progressed toward the 1st objective. A recent search of the literature uncovered few series of SR of more than 50 cases. The 767 operations found were analyzed with regard to pregnancy outcome. The precent of live births varied from 74-78.8%, and the occurance of tubal pregnancies ranged from 1.7-6.5%. All of the confounding variables in patient selection and small numbers of reported procedures preclude any conclusion about the different techniques or the number of operations that give a surgeon a level of expertise. Few authors classify their

  19. Reverse Logistics in Food Supply Chains

    NARCIS (Netherlands)

    Zeimpekis, V.; Bloemhof, J.M.; Bourlakis, M.

    2014-01-01

    Reverse logistics can be defined as the process of planning, implementing, and controlling the flow of raw materials, in-process inventory, and finished goods from the point of consumption to the point of origin for the purpose of recapturing value or proper disposal. In environmental and economic

  20. Linear programming foundations and extensions

    CERN Document Server

    Vanderbei, Robert J

    2001-01-01

    Linear Programming: Foundations and Extensions is an introduction to the field of optimization. The book emphasizes constrained optimization, beginning with a substantial treatment of linear programming, and proceeding to convex analysis, network flows, integer programming, quadratic programming, and convex optimization. The book is carefully written. Specific examples and concrete algorithms precede more abstract topics. Topics are clearly developed with a large number of numerical examples worked out in detail. Moreover, Linear Programming: Foundations and Extensions underscores the purpose of optimization: to solve practical problems on a computer. Accordingly, the book is coordinated with free efficient C programs that implement the major algorithms studied: -The two-phase simplex method; -The primal-dual simplex method; -The path-following interior-point method; -The homogeneous self-dual methods. In addition, there are online JAVA applets that illustrate various pivot rules and variants of the simplex m...

  1. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  2. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  3. A categorical foundation for structured reversible flowchart languages: Soundness and adequacy

    OpenAIRE

    Glück, Robert; Kaarsgaard, Robin

    2017-01-01

    Structured reversible flowchart languages is a class of imperative reversible programming languages allowing for a simple diagrammatic representation of control flow built from a limited set of control flow structures. This class includes the reversible programming language Janus (without recursion), as well as more recently developed reversible programming languages such as R-CORE and R-WHILE. In the present paper, we develop a categorical foundation for this class of languages based on inve...

  4. abc: An extensible AspectJ compiler

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie

    2005-01-01

    checking and code generation, as well as data flow and control flow analyses. The AspectBench Compiler (abc) is an implementation of such a workbench. The base version of abc implements the full AspectJ language. Its frontend is built, using the Polyglot framework, as a modular extension of the Java...... language. The use of Polyglot gives flexibility of syntax and type checking. The backend is built using the Soot framework, to give modular code generation and analyses. In this paper, we outline the design of abc, focusing mostly on how the design supports extensibility. We then provide a general overview...

  5. Extensible packet processing architecture

    Science.gov (United States)

    Robertson, Perry J.; Hamlet, Jason R.; Pierson, Lyndon G.; Olsberg, Ronald R.; Chun, Guy D.

    2013-08-20

    A technique for distributed packet processing includes sequentially passing packets associated with packet flows between a plurality of processing engines along a flow through data bus linking the plurality of processing engines in series. At least one packet within a given packet flow is marked by a given processing engine to signify by the given processing engine to the other processing engines that the given processing engine has claimed the given packet flow for processing. A processing function is applied to each of the packet flows within the processing engines and the processed packets are output on a time-shared, arbitered data bus coupled to the plurality of processing engines.

  6. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  7. Journal of Agricultural Extension

    African Journals Online (AJOL)

    Scope of journal The Journal of Agricultural Extension" is devoted to the advancement of knowledge of agricultural extension services and practice through the publication of original and empirically based research, ... Vol 22, No 1 (2018) ... Symbol recognition and interpretation of HIV/AIDS pictorial messages among rural ...

  8. Priorities for Extension.

    Science.gov (United States)

    Hayward, J. A.

    Agricultural extension is one component in an array including research, training, education, marketing, international trade, etc. which develop together to bring about growth, and sustained growth determines the priorities for extension. These priorities depend inevitably on the stage of development of a country or region, and on the current…

  9. Nuclear plant life extension

    International Nuclear Information System (INIS)

    Negin, C.A.

    1989-01-01

    The nuclear power industry's addressing of life extension is a natural trend in the maturation of this technology after 20 years of commercial operation. With increasing emphasis on how plants are operated, and less on how to build them, attention is turning on to maximizing the use of these substantial investments. The first studies of life extension were conducted in the period from 1978 and 1982. These were motivated by the initiation, by the Nuclear Regulatory Commission (NRC), of studies to support decommissioning rulemaking. The basic conclusions of those early studies that life extension is feasible and worth pursuing have not been changed by the much more extensive investigations that have since been conducted. From an engineering perspective, life extension for nuclear plants is fundamentally the same as for fossil plants

  10. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  11. On thermodynamic and microscopic reversibility

    International Nuclear Information System (INIS)

    Crooks, Gavin E

    2011-01-01

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa

  12. Dettol: Managing Brand Extensions

    OpenAIRE

    Anand Kumar Jaiswal; Arpita Srivastav; Dhwani Kothari

    2009-01-01

    This case is about evolution of a parent brand and its subsequent extensions into different product categories. Dettol as a brand has immense trust and loyalty from the consumers. Since the 1930s when Dettol was introduced in India, it has occupied a distinct position in the mind of its consumers. To achieve fast growth and leverage the strong brand equity of Dettol, Reckitt Benckiser India Limited (RBIL) rolled out a number of brand extensions. Some of these extensions such as Dettol soap an...

  13. Spacetime extensions Pt. 1

    International Nuclear Information System (INIS)

    Racz, I.

    1991-09-01

    The problem of the existence of local extensions of spacetime is considered. It is shown that for a spacetime including an incomplete inextendible non-coiling causal geodesic curve there exists a particular C k (resp. C k- ) local extension provided that the curvature and its covariant derivatives are well behaved up to order k + 1 (resp. k) along a family of causal geodetics (around the chosen one). (R.P.) 15 refs

  14. Type extension trees

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We introduce type extension trees as a formal representation language for complex combinatorial features of relational data. Based on a very simple syntax this language provides a unified framework for expressing features as diverse as embedded subgraphs on the one hand, and marginal counts...... of attribute values on the other. We show by various examples how many existing relational data mining techniques can be expressed as the problem of constructing a type extension tree and a discriminant function....

  15. Model of reverse steam generator

    International Nuclear Information System (INIS)

    Malasek, V.; Manek, O.; Masek, V.; Riman, J.

    1987-01-01

    The claim of Czechoslovak discovery no. 239272 is a model designed for the verification of the properties of a reverse steam generator during the penetration of water, steam-water mixture or steam into liquid metal flowing inside the heat exchange tubes. The design may primarily be used for steam generators with a built-in inter-tube structure. The model is provided with several injection devices configured in different heat exchange tubes, spaced at different distances along the model axis. The design consists in that between the pressure and the circumferential casings there are transverse partitions and that in one chamber consisting of the circumferential casings, pressure casing and two adjoining partitions there is only one passage of the injection device through the inter-tube space. (Z.M.). 1 fig

  16. Less extensive surgery compared to extensive surgery

    DEFF Research Database (Denmark)

    Lauszus, Finn F; Petersen, Astrid C; Neumann, Gudrun

    2014-01-01

    -up by hospital data files, general practitioner, death certificate, and autopsy report. Revision of histopathology by a single pathologist. Main outcome measures: Survival and relapse by clinical data, stage, and type of surgery. RESULTS: The incidence of AGCT was 1.37 per year per 100,000 women (95% CI: 1.08, 1.......68). The median follow-up time was 15 years and for the 79 surviving women 22 years. Stage I was found in 94% of cases. Relapse occurred in 24% of women in stage I and 100% of the other stages. Survival in stage I was 95%, 89% and 84% after 5, 10 and 20 years respectively. Increased survival of stage I......: The survival of women was better in AGCT than in epithelial ovarian tumor. Age and type of surgery, besides stage, influenced survival. Total abdominal hysterectomy and bilateral salpingo-oophorectomy is the recommended treatment with advancing age. At younger age less extensive surgery was associated...

  17. Catastrophic failure of polymer melts during extension

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.

    2013-01-01

    Numerical flow modeling has been applied to study the break of monodisperse polymer melts during extension. These continuum mechanical based computations are within the ideas of the microstructural ’interchain pressure’ theory. Calculated breaks, a result of small initial sample imperfections, ag...

  18. Reversal permanent charge and reversal potential: case studies via classical Poisson–Nernst–Planck models

    International Nuclear Information System (INIS)

    Eisenberg, Bob; Liu, Weishi; Xu, Hongguo

    2015-01-01

    In this work, we are interested in effects of a simple profile of permanent charges on ionic flows. We determine when a permanent charge produces current reversal. We adopt the classical Poisson–Nernst–Planck (PNP) models of ionic flows for this study. The starting point of our analysis is the recently developed geometric singular perturbation approach for PNP models. Under the setting in the paper for case studies, we are able to identify a single governing equation for the existence and the value of the permanent charge for a current reversal. A number of interesting features are established. The related topic on reversal potential can be viewed as a dual problem and is briefly examined in this work too. (paper)

  19. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  20. Economic impact of reversion

    International Nuclear Information System (INIS)

    2005-01-01

    Estimations of the Norwegian hydropower production and various reversion models' market value have been made. The value of the Norwegian hydropower production until 01.01.2007 is estimated to about Nok 289 billion after taxes, or about 2,42 Nok/kWh medium production, given an expected future electricity price of around 0,25 Nok/kWh and a discount rate at 6,5 percent in nominal terms after taxes. The estimate is slightly above the level of prices for Norwegian hydropower plants in the last 8-10 years. The value of reversion in private plants which today have a limited licence time is estimated to Nok 5,5 billion. The value of reversion in public-owned Norwegian hydropower plants are about Nok 21 billion with a 60 year licence period from 01.01.2007, and about 12 billion for 75 years (ml)

  1. REVERSIBLE VENTILATION SYSTEM FOR ADMINISTRATIVE BUILDINGS

    Directory of Open Access Journals (Sweden)

    Valery Yu. Kravchuk

    2017-01-01

    Full Text Available Abstract. Objectives To consider the possibility of applying the principle of reversing air flows for a centralised ventilation system; to develop a specific scheme for air exchange reversible ventilation, which will take into account the peculiarities of the microclimate of administrative buildings; to select the type of filling of the air-permeable element and justify this choice; to determine the conditions for changing the direction of air movement in the ventilation system and the area of its application; to form a list of equipment necessary for the operation of such a system; to consider the influence of supply and exhaust devices on the heat and humidity regime of claddings. Methods  To achieve this goal, the published thematic material was reviewed and a patent search carried out using Russian and European databases. Data on mathematical modelling of filtration in porous media and experimental results were used. A method for ventilating rooms in administrative building using the reversal of movement of supply and exhaust air streams along the same channels was applied. Results  Schemas for reversible ventilation systems are presented and their modes of operation considered. It is established that the idea of reversing ventilation flows has not yet been applied in the development of centralised ventilation systems. Based on these published materials, it was concluded that the proposed design of supply and exhaust devices can be used in practice. An original air exchange scheme for the ventilation of administrative buildings and design of supply and exhaust devices for this system are proposed. The conditions for changing the operating modes of the system and the scope of its application are determined. Conclusion The use of the proposed ventilation system allows normative air exchange to be provided without using a supply unit during the cold season. This application of airflow reversal allows the potential of natural forces to be used

  2. Reversible deep disposal

    International Nuclear Information System (INIS)

    2009-10-01

    This presentation, given by the national agency of radioactive waste management (ANDRA) at the meeting of October 8, 2009 of the high committee for the nuclear safety transparency and information (HCTISN), describes the concept of deep reversible disposal for high level/long living radioactive wastes, as considered by the ANDRA in the framework of the program law of June 28, 2006 about the sustainable management of radioactive materials and wastes. The document presents the social and political reasons of reversibility, the technical means considered (containers, disposal cavities, monitoring system, test facilities and industrial prototypes), the decisional process (progressive development and blocked off of the facility, public information and debate). (J.S.)

  3. Fluorescein-related extensive jaundice.

    Science.gov (United States)

    Kalkan, Asim; Turedi, Suleyman; Aydin, Ibrahim

    2015-03-01

    Fluorescein is a chemical dye frequently used in eye diseases to assess blood flow in the retina, choroid tissue, and iris. Although it has many known adverse effects, it has not previously been reported to lead to jaundice. The purpose of this case report was to emphasize that for patients presenting at the emergency department with jaundice symptoms, it should not be forgotten by emergency physicians that jaundice can develop after fluorescein angiography. Case: A 65-year-old woman presented at the emergency department with extensive jaundice that had developed on her entire body a few hours after fluorescein angiography applied because of vision impairment. The test results for all the diseases considered to cause jaundice were normal,and fluorescein-related jaundice was diagnosed. Conclusion: A detailed anamnesis should be taken when jaundice is seen in patients who have undergone fluorescein angiography, and it should not be forgotten that fluorescein dye is a rare cause of jaundice.

  4. AN OVERVIEW ON RETAIL REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-07-01

    Full Text Available This article is a theoretical approach on retail reverse logistics. Environmental concern and the current marketing strategy have spurred retailers to implement strategies to facilitate product returns from end customers. Reverse logistics, indicating the process of this return flow, encompasses such activities as the movement of returned products, facilities to accommodate returned items, and overall remedy process for returned items. The retail industry, under great competitive pressure, has used return policies as a competitive weapon. Grocery retailers were the first to begin to focus serious attention on the problem of returns and to develop reverse logistics innovations. Grocery retailers first developed innovations such as reclamation centers. Reclamation centers, in turn, led to the establishment of centralized return centers. Centralizing returns has led to significant benefits for most firms that have implemented them. Over the last several years, retailers have consolidated. Now, more than ever, reverse logistics is seen as being important. This reverse distribution activity can be crucial to the survival of companies, because the permanent goodwill of the company is at stake. Businesses succeed because they respond to both external and internal changes and adjust in an effective manner to remain competitive.

  5. Thermosensory reversal effect quantified

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.

    2008-01-01

    At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of 'cold' and 'warm' materials are reversed. In this paper, this effect is quantified by

  6. Thermosensory reversal effect quantified

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.

    2008-01-01

    At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of ‘cold’ and ‘warm’ materials are reversed. In this paper, this effect is quantified by

  7. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  8. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  9. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  10. Elastomers with Reversible Nanoporosity

    DEFF Research Database (Denmark)

    Szewczykowski, Piotr Przemyslaw; Andersen, K.; Schulte, Lars

    2009-01-01

    nanostructure and displays liquid-filled cavities. Upon several cycles of swelling and drying the cavities open and close in a reversible fashion. When exposed to a nonsolvent, the material remains collapsed. This discriminating behavior of liquid-material interaction holds potential for the use...

  11. Android Access Control Extension

    Directory of Open Access Journals (Sweden)

    Anton Baláž

    2015-12-01

    Full Text Available The main objective of this work is to analyze and extend security model of mobile devices running on Android OS. Provided security extension is a Linux kernel security module that allows the system administrator to restrict program's capabilities with per-program profiles. Profiles can allow capabilities like network access, raw socket access, and the permission to read, write, or execute files on matching paths. Module supplements the traditional Android capability access control model by providing mandatory access control (MAC based on path. This extension increases security of access to system objects in a device and allows creating security sandboxes per application.

  12. Life extension economic analysis

    International Nuclear Information System (INIS)

    Smithling, A.P.

    1992-01-01

    Life extension economic analyses of fossil fueled power plants need the development of consistent methods which consider the capital costs associated with component replacement or repair and estimates of normal station capital expenditures over the units remaining life. In order to link capital and production costs, Niagra Mohawk Power Corp. develops most and worst cases. A most case includes capital components that would definitely need replacement or modification for life extension. The worst case scenario contains must case capital costs plus various components which may need replacement or modification. In addition, two forecasted conditions are used, base case capacity and low capacity

  13. Reverse Estuarine Circulation Due to Local and Remote Wind Forcing, Enhanced by the Presence of Along-Coast Estuaries

    Science.gov (United States)

    Giddings, S. N.; MacCready, P.

    2017-12-01

    Estuarine exchange flow governs the interaction between oceans and estuaries and thus plays a large role in their biogeochemical processes. This study investigates the variability in estuarine exchange flow due to offshore oceanic conditions including upwelling/downwelling, and the presence of a river plume offshore (from a neighboring estuary). We address these processes via numerical simulations at the mouth of the Salish Sea, a large estuarine system in the Northeast Pacific. An analysis of the Total Exchange Flow indicates that during the upwelling season, the exchange flow is fairly consistent in magnitude and oriented in a positive (into the estuary at depth and out at the surface) direction. However, during periods of downwelling favorable winds, the exchange flow shows significantly more variability including multiple reversals, consistent with observations, and surface intrusions of the Columbia River plume which originates 250 km to the south. Numerical along-strait momentum budgets show that the exchange flow is forced dominantly by the pressure gradients, particularly the baroclinic. The pressure gradient is modified by Coriolis and sometimes advection, highlighting the importance of geostrophy and local adjustments. In experiments conducted without the offshore river plume, reversals still occur but are weaker, and the baroclinic pressure gradient plays a reduced role. These results suggest that estuaries along strong upwelling coastlines should experience significant modulation in the exchange flow during upwelling versus downwelling conditions. Additionally, they highlight the importance of nearby estuaries impacting one-another, not only in terms of connectivity, but also altering the exchange flow.Plain Language SummaryEstuarine systems provide extensive biological and ecological functions as well as contribute to human uses and economies. However, estuaries are susceptible to change and most estuaries have been significantly impacted, threatening

  14. Formalized Planning and Its Connection With the Development of Reverse Logistics: the Case of Services

    Directory of Open Access Journals (Sweden)

    Radoslav Škapa

    2014-01-01

    Full Text Available The best-in-class companies are able to retrieve 64 per cent of the original value of reverse flows, whereas it is only 12.5 per cent in average companies. Thus, reverse logistics is a challenge that may bring additional benefits. The article analyzes the planning range of reverse logistics in the Czech service companies, and it further notes the relations between planning and other characteristics of a company. Our results indicate that the ability to recognize different connections of reverse flows in business (opportunities, threats as well as strengths and weaknesses is one of the important factors that affect the advancement of reverse logistics in companies.

  15. Mobile Applications for Extension

    Science.gov (United States)

    Drill, Sabrina L.

    2012-01-01

    Mobile computing devices (smart phones, tablets, etc.) are rapidly becoming the dominant means of communication worldwide and are increasingly being used for scientific investigation. This technology can further our Extension mission by increasing our power for data collection, information dissemination, and informed decision-making. Mobile…

  16. Reverse logistics policy – differences between conservative and innovative reverse logistics management

    Directory of Open Access Journals (Sweden)

    Alena Klapalová

    2013-01-01

    Full Text Available One of the of the key barriers that hampers effective and efficient management of reverse flows detected within a number of empirical surveys and case studies focused on reverse logistics and/or return management is business (organisational policy, specifically lack of policy, deficiency in existing policy or inferior policy. Despite this fact, there is a gap in literature which would show some evidence from practice that innovative reverse logistics policy both can pay off and is associated with certain aspects of reverse logistics management. Such proof can have several implications. It can support the call for better understanding and more research of the linkages of reverse logistics with other corporate functions, promote the acceptation of strategic character of reverse logistics and stress the role of RL policy within the rest of overall corporate management.The aim of this paper is to contribute and to enrich the existing body of knowledge concerning the above-mentioned gap through presentation of survey results that was realized in 2012 among managers of 244 Czech firms. The results demonstrate the statistically significant association between the innovativeness of RL policy and profitability of firms, quality of RL planning, perception of RL importance, level of RL knowledge and perception of product innovation importance for firms’ competitiveness and frequency of product innovation. They also reveal statistically significant differences between firms with conservative and innovative RL policy and the perceived existence of some barriers to manage RL.

  17. Reversed field pinch diagnostics

    International Nuclear Information System (INIS)

    Weber, P.G.

    1986-01-01

    The Reversed Field Pinch (RFP) is a toroidal, axisymmetric magnetic confinement configuration characterized by a magnetic field configuration in which the toroidal magnetic field is of similar strength to the poloidal field, and is reversed at the edge compared to the center. The RFP routinely operates at high beta, and is a strong candidate for a compact fusion device. Relevant attributes of the configuration will be presented, together with an overview of present and planned experiments and their diagnostics. RFP diagnostics are in many ways similar to those of other magnetic confinement devices (such as tokamaks); these lectures will point out pertinent differences, and will present some diagnostics which provide special insights into unique attributes of the RFP

  18. Posterior Reversible Encephalopathy (PRES)

    International Nuclear Information System (INIS)

    Moron E, Fanny E; Diaz Marchan, Pedro

    2005-01-01

    The Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical Syndrome composed of cephalea, alteration in vision and convulsions, usually observed in patients with sudden elevation of arterial pressure. The imagenologic evidence shows reversible vasogenic brain edema without stroke. Its location is predominantly posterior; it affects the cortex and the subcortical white matter of the occipital, parietal and temporal lobes. The treatment with antihypertensive drugs and the removing of immunosupressor medication are generally associated with complete neurological recovery; this is reflected also in the images which return to their basal condition. The untreated hypertension, on the other side, can result in a progressive defect of the autoregulation system of the central nervous system with cerebral hemorrhage, irreversible brain stroke, coma and death

  19. Dynamical similarity of geomagnetic field reversals.

    Science.gov (United States)

    Valet, Jean-Pierre; Fournier, Alexandre; Courtillot, Vincent; Herrero-Bervera, Emilio

    2012-10-04

    No consensus has been reached so far on the properties of the geomagnetic field during reversals or on the main features that might reveal its dynamics. A main characteristic of the reversing field is a large decrease in the axial dipole and the dominant role of non-dipole components. Other features strongly depend on whether they are derived from sedimentary or volcanic records. Only thermal remanent magnetization of lava flows can capture faithful records of a rapidly varying non-dipole field, but, because of episodic volcanic activity, sequences of overlying flows yield incomplete records. Here we show that the ten most detailed volcanic records of reversals can be matched in a very satisfactory way, under the assumption of a common duration, revealing common dynamical characteristics. We infer that the reversal process has remained unchanged, with the same time constants and durations, at least since 180 million years ago. We propose that the reversing field is characterized by three successive phases: a precursory event, a 180° polarity switch and a rebound. The first and third phases reflect the emergence of the non-dipole field with large-amplitude secular variation. They are rarely both recorded at the same site owing to the rapidly changing field geometry and last for less than 2,500 years. The actual transit between the two polarities does not last longer than 1,000 years and might therefore result from mechanisms other than those governing normal secular variation. Such changes are too brief to be accurately recorded by most sediments.

  20. Absolute paleointensities during a mid Miocene reversal of the Earth's magnetic field recorded on Gran Canaria (Canary Islands)

    Science.gov (United States)

    Leonhardt, R.; Soffel, H. C.

    2001-12-01

    An extensive paleointensity study was carried out on an approximately 14.1 Myr old reverse to normal transition of the geomagnetic field. One hundred eighty-eight samples from a mid Miocene volcanic sequence on Gran Canaria (Canary Islands) were subjected to Thellier-type paleointensity determinations. Samples for paleointensity experiments were selected on the basis of high Curie temperatures, low viscosity indexes, and limited variations of the remanence-carrying magnetic content during thermal treatment. A modified Thellier technique, which facilitates the recognition of MD tails and the formation of new magnetic remanences with higher blocking temperatures than the actual heating step, was used on the majority of the samples. The application of this technique proved to be very successful and we obtained reliable paleointensity results for 35% of the 87 sampled lava flows. In general, the intensity of the reversed and normal magnetized parts of the sequence, before and after the transition, is lower than the field intensity expected for the mid Miocene. This observation is very likely related to a long term reduction of the field close to transitions. The mean field intensity after the reversal ( ~ 17 μ T) is about twice the value of that recorded in the rocks prior to the reversal. This observation points at a fast recovery of the dipolar structure of the field after this reversal. Very low paleointensities with values < 5 μ T were obtained during an excursion, preceding the actual transition, and also close to significant changes of the local field directions during the reversal. This is interpreted as non-dipolar components becoming dominant for short periods and provoking a rapid change of local field directions. During the transition 15 successive lava flows recorded similar local field directions corresponding to a cluster of virtual geomagnetic poles close to South America. Chronologically, within this cluster the paleointensity increases from about 9

  1. Stress coping strategies among agricultural extension agents in Oyo ...

    African Journals Online (AJOL)

    Stress coping strategies among agricultural extension agents in Oyo State, Nigeria. ... Journal Home > Vol 20, No 1 (2016) >. Log in or ... Employees should have control over work flow to reduce work stress and increase work efficiency.

  2. Analytical extension of curved shock theory

    Science.gov (United States)

    Emanuel, G.

    2018-03-01

    Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.

  3. Positioning paper on reversibility

    International Nuclear Information System (INIS)

    2016-01-01

    After having recalled the legal framework adopted in 2006 for the deep geological storage of radioactive wastes, and briefly introduced the concept of reversibility, this publication presents the principle of geological storage, presents high and medium level and long life wastes, highlights the ethical necessity to deal with these radioactive wastes, outlines that geological storage is the generally admitted and adopted solution at the international level, and presents additional means implemented for radioactive waste management. It presents the Cigeo project as the technical answer to the issue of radioactive waste storage, describes the Cigeo development process, its current status and its development planning, and justifies the choice of this technical solution, notably from an ethical point of view. It addresses the issue of reversibility and proposes an overview of the various tools and means which aim at guaranteeing this reversibility. Appendices propose figures illustrating the Cigeo project and its development process, and a rather detailed Power Point presentation of the project by the ANDRA (history, object, planning, installations, and so on)

  4. Extension without Cut

    OpenAIRE

    Straßburger , Lutz

    2012-01-01

    International audience; In proof theory one distinguishes sequent proofs with cut and cut-free sequent proofs, while for proof complexity one distinguishes Frege-systems and extended Frege-systems. In this paper we show how deep inference can provide a uniform treatment for both classifications, such that we can define cut-free systems with extension, which is neither possible with Frege-systems, nor with the sequent calculus. We show that the propositional pigeon-hole principle admits polyno...

  5. Dimension and extensions

    CERN Document Server

    Aarts, JM

    1993-01-01

    Two types of seemingly unrelated extension problems are discussed in this book. Their common focus is a long-standing problem of Johannes de Groot, the main conjecture of which was recently resolved. As is true of many important conjectures, a wide range of mathematical investigations had developed, which have been grouped into the two extension problems. The first concerns the extending of spaces, the second concerns extending the theory of dimension by replacing the empty space with other spaces. The problem of de Groot concerned compactifications of spaces by means of an adjunction of a set of minimal dimension. This minimal dimension was called the compactness deficiency of a space. Early success in 1942 lead de Groot to invent a generalization of the dimension function, called the compactness degree of a space, with the hope that this function would internally characterize the compactness deficiency which is a topological invariant of a space that is externally defined by means of compact extensions of a...

  6. Status of time reversal invariance

    International Nuclear Information System (INIS)

    Henley, E.M.

    1989-01-01

    Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed. 30 refs., 2 figs., 1 tab

  7. Introduction to time reversal theory

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Theory and reaction mechanisms relevant to time reversal invariance are reviewed. Consequences of time reversal invariance are presented under the headings of CP tests, electromagnetic moments, weak emissions or absorptions, and scattering reactions. 8 refs., 4 figs

  8. Polymeric liquids in extension: fluid mechanics or rheometry?

    DEFF Research Database (Denmark)

    Hassager, Ole; Marin, Jose Martin Roman; Yu, Kaijia

    2010-01-01

    (IA). It is demonstrated that the actual kinematics in this rheometer is a mixture of planar and uniaxial extension. Moreover, the ratio of planar to uniaxial deformation is highly dependent upon whether IA is invoked. Without IA, the flow has a tendency toward planar extension, while it tends...

  9. The Causes of Preference Reversal.

    OpenAIRE

    Tversky, Amos; Slovic, Paul; Kahneman, Daniel

    1990-01-01

    Observed preference reversal cannot be adequately explained by violations of independence, the reduction axiom, or transitivity. The primary cause of preference reversal is the failure of procedure invariance, especially the overpricing of low-probability, high-payoff bets. This result violates regret theory and generalized (nonindependent) utility models. Preference reversal and a new reversal involving time preferences are explained by scale compatibility, which implies that payoffs are wei...

  10. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  11. A Study on Reverse Logistics

    OpenAIRE

    Reddy, Dhananjaya

    2011-01-01

    In the competitive world of manufacturing, companies are often searching for new ways to improve their process, customer satisfaction and stay ahead in the game with their competitors. Reverse logistics has been considered a strategy to bring these things to life for the past decade or so. This thesis work tries to shed some light on the basics of reverse logistics and how reverse logistics can be used as a management strategy. This paper points out the fundamentals of reverse logistics and l...

  12. Inorganic fouling mitigation by salinity cycling in batch reverse osmosis

    OpenAIRE

    Maswadeh, Laith A.; Warsinger, David Elan Martin; Tow, Emily W.; Connors, Grace B.; Swaminathan, Jaichander; Lienhard, John H

    2018-01-01

    Enhanced fouling resistance has been observed in recent variants of reverse osmosis (RO) desalination which use time-varying batch or semi-batch processes, such as closed-circuit RO (CCRO) and pulse flow RO (PFRO). However, the mechanisms of batch processes' fouling resistance are not well-understood, and models have not been developed for prediction of their fouling performance. Here, a framework for predicting reverse osmosis fouling is developed by comparing the fluid residence time in bat...

  13. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-09

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency.

  14. Reverse-Tangent Injection in a Centrifugal Compressor

    Science.gov (United States)

    Skoch, Gary J.

    2007-01-01

    Injection of working fluid into a centrifugal compressor in the reverse tangent direction has been invented as a way of preventing flow instabilities (stall and surge) or restoring stability when stall or surge has already commenced. The invention applies, in particular, to a centrifugal compressor, the diffuser of which contains vanes that divide the flow into channels oriented partly radially and partly tangentially. In reverse-tangent injection, a stream or jet of the working fluid (the fluid that is compressed) is injected into the vaneless annular region between the blades of the impeller and the vanes of the diffuser. As used here, "reverse" signifies that the injected flow opposes (and thereby reduces) the tangential component of the velocity of the impeller discharge. At the same time, the injected jet acts to increase the radial component of the velocity of the impeller discharge.

  15. Continuous multivariate exponential extension

    International Nuclear Information System (INIS)

    Block, H.W.

    1975-01-01

    The Freund-Weinman multivariate exponential extension is generalized to the case of nonidentically distributed marginal distributions. A fatal shock model is given for the resulting distribution. Results in the bivariate case and the concept of constant multivariate hazard rate lead to a continuous distribution related to the multivariate exponential distribution (MVE) of Marshall and Olkin. This distribution is shown to be a special case of the extended Freund-Weinman distribution. A generalization of the bivariate model of Proschan and Sullo leads to a distribution which contains both the extended Freund-Weinman distribution and the MVE

  16. Extensive air showers

    CERN Document Server

    Rao, M V S

    1997-01-01

    Ultrahigh energy cosmic rays carry information about their sources and the intervening medium apart from providing a beam of particles for studying certain features of high energy interactions currently inaccessible at man-made accelerators. They can at present be studied only via the extensive air showers (EAS's) they generate while passing through the Earth's atmosphere, since their fluxes are too low for the experiments of limited capability flown in balloons and satellites. The EAS is generated by a series of interactions of the primary cosmic ray and its progeny with the atmospheric nucle

  17. The topology of intrasector reversals of the interplanetary magnetic field

    Science.gov (United States)

    Kahler, S. W.; Crooker, N. U.; Gosling, J. T.

    1996-11-01

    A technique has been developed recently to determine the polarities of interplanetary magnetic fields relative to their origins at the Sun by comparing energetic electron flow directions with local magnetic field directions. Here we use heat flux electrons from the Los Alamos National Laboratory (LANL) plasma detector on the ISEE 3 spacecraft to determine the field polarities. We examine periods within well-defined magnetic sectors when the field directions appear to be reversed from the normal spiral direction of the sector. About half of these intrasector field reversals (IFRs) are cases in which the polarities match those of the surrounding sectors, indicating that those fields have been folded back toward the Sun. The more interesting cases are those with polarity reversals. We find no clear cases of isolated reverse polarity fields, which suggests that islands of reverse polarity in the solar source dipole field probably do not exist. The IFRs with polarity reversals are strongly associated with periods of bidirectional electron flows, suggesting that those fields occur only in conjunction with closed fields. We propose that both those IFRs and the bidirectional flows are signatures of coronal mass ejections (CMEs). In that case, many interplanetary CMEs are larger and more complex than previously thought, consisting of both open and closed field components.

  18. Reversal Strategies for NOACs

    DEFF Research Database (Denmark)

    Husted, Steen; Verheugt, Freek; Comuth, Willemijn

    2015-01-01

    , coagulation factor concentrates or NOAC-specific antidotes could be used. Coagulation factor concentrates can be used in patients with haemophilia and to reverse the effect of VKAs but, in NOAC-treated patients, results are inconsistent and these agents could potentially have pro-thrombotic effects. Specific...... antidotes for NOACs are expected to be on the market soon. Phase III clinical trials with a humanized antibody fragment directed against dabigatran (idarucizumab) and recombinant, modified factor Xa (andexanet alfa) are ongoing. A molecule (aripazine) with broad activity against various anticoagulants...

  19. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  20. Reversible airfoils for stopped rotors in high speed flight

    International Nuclear Information System (INIS)

    Niemiec, Robert; Jacobellis, George; Gandhi, Farhan

    2014-01-01

    This study starts with the design of a reversible airfoil rib for stopped-rotor applications, where the sharp trailing-edge morphs into the rounded leading-edge, and vice-versa. A NACA0012 airfoil is approximated in a piecewise linear manner and straight, rigid outer profile links used to define the airfoil contour. The end points of the profile links connect to control links, each set on a central actuation rod via an offset. Chordwise motion of the actuation rod moves the control and the profile links and reverses the airfoil. The paper describes the design methodology and evolution of the final design, based on which two reversible airfoil ribs were fabricated and used to assemble a finite span reversible rotor/wing demonstrator. The profile links were connected by Aluminum strips running in the spanwise direction which provided stiffness as well as support for a pre-tensioned elastomeric skin. An inter-rib connector with a curved-front nose piece supports the leading-edge. The model functioned well and was able to reverse smoothly back-and-forth, on application and reversal of a voltage to the motor. Navier–Stokes CFD simulations (using the TURNS code) show that the drag coefficient of the reversible airfoil (which had a 13% maximum thickness due to the thickness of the profile links) was comparable to that of the NACA0013 airfoil. The drag of a 16% thick elliptical airfoil was, on average, about twice as large, while that of a NACA0012 in reverse flow was 4–5 times as large, even prior to stall. The maximum lift coefficient of the reversible airfoil was lower than the elliptical airfoil, but higher than the NACA0012 in reverse flow operation. (paper)

  1. Reversal of subtidal dune asymmetries caused by seasonally reversing wind-driven currents in Torres Strait, northeastern Australia

    Science.gov (United States)

    Harris, Peter T.

    1991-07-01

    Large subtidal sand dunes (sandwaves) located in Adolphus Channel, Torres Strait, have been observed to reverse their asymmetric orientation between September-February. This has been attributed to a reversal in wind-driven currents, which flow westward during the SE trade season (April-November) and eastwards during the NW monsoon season [December-March: HARRIS (1989) Continental Shelf Research, 9, 981-1002]. Observations in September 1988 and February 1989 from another area of dunes in Torres Strait corroborate this asymmetry reversal pattern. The results indicate that such reversals may be common in Torres Strait and in other areas where subtidal bedforms are subject to modification by superimposed, seasonally reversing, wind-driven currents.

  2. Industrial complementarities between interim storage and reversible geological repository - 59237

    International Nuclear Information System (INIS)

    Hoorelbeke, Jean-Michel

    2012-01-01

    The French Act voted in 2006 made the choice of deep geological disposal as the reference option for the long term management of high level (HLW) and intermediate level long-lived waste. The CIGEO repository project aims at avoiding or limiting burden to future generations, which could not be achieved by the extension in time of interim storage. The reversibility as provided by the Act will maintain a liberty of choice for waste management on a duration which is comparable to new storage facility. Interim storage is required to accommodate waste as long as the repository is not available. The commissioning of the repository in 2025 will not suppress needs for interim storage. The paper describes the complementarities between existing and future interim storage facilities and the repository project: repository operational issues and planning, HLW thermal decay, support for the reversibility, etc. It shows opportunities to prepare a global optimization of waste management including the utilization at best of storage capacities and the planning of waste emplacement in the repository in such a way to facilitate operational conditions and to limit cost. Preliminary simulations of storage-disposal scenarios are presented. Thanks to an optimal use of the waste management system, provision can be made for a progressive increase of waste emplacement flow during the first operation phase of the repository. It is then possible to stabilize the industrial activity level of the repository site. An optimal utilization of interim storage can also limit the diversity of waste packages emplaced simultaneously, which facilitates the operation of the repository. 60 years minimum interim storage duration is generally required with respect to HLW thermal output. Extending this interim storage period may reduce the underground footprint of the repository. Regarding reversibility, the capability to manage waste packages potentially retrieved from the repository should be analyzed. The

  3. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  4. Laser heating of field-reversed configurations

    International Nuclear Information System (INIS)

    Carson, R.S.; Vlases, G.C.

    1983-01-01

    The experimental facility is a 21-cm-long solenoid with a 5.5-cm bore. The 4-cm ID quartz tube is filled with slowly flowing H 2 to 0.5-3.0 torr. Fields up to 6.5 T in 3.7 μsec are produced, with reverse-bias fields up -1.9 T. Preionization is by 40kA axial discharge 4.5 μsec before field-reversal is begun. The CO 2 laser used produces 300 to 400 J in 2 μsec, in an annular beam that can be defocused for preheating the outer edges of the plasma, or focused tightly for central-column heating and beam propagation during formation. The focusing system includes a return mirror for multiple passing of the laser energy. Diagnostics include compensated, diamagnetic flux loops, internal field probes, cross-tube and axial interferometers, fast photography, and spectroscopy

  5. An Efficient Forward-Reverse EM Algorithm for Statistical Inference in Stochastic Reaction Networks

    KAUST Repository

    Bayer, Christian; Moraes, Alvaro; Tempone, Raul; Vilanova, Pedro

    2016-01-01

    In this work [1], we present an extension of the forward-reverse algorithm by Bayer and Schoenmakers [2] to the context of stochastic reaction networks (SRNs). We then apply this bridge-generation technique to the statistical inference problem

  6. Reference genes for reverse transcription quantitative PCR in canine brain tissue

    NARCIS (Netherlands)

    Stassen, Quirine E M; Riemers, Frank M; Reijmerink, Hannah; Leegwater, Peter A J; Penning, Louis C

    2015-01-01

    BACKGROUND: In the last decade canine models have been used extensively to study genetic causes of neurological disorders such as epilepsy and Alzheimer's disease and unravel their pathophysiological pathways. Reverse transcription quantitative polymerase chain reaction is a sensitive and

  7. Ground System Extensibility Considerations

    Science.gov (United States)

    Miller, S. W.; Greene, E.

    2017-12-01

    The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The Joint Polar Satellite System will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a multi-mission enterprise system serving NOAA, NASA and their national and international partners, such as NASA's Earth Observation System (EOS), NOAA's current POES, the Japan Aerospace Exploration Agency's (JAXA) Global Change Observation Mission - Water (GCOM-W1), and DoD's Defense Meteorological Satellite Program (DMSP). The CGS provides a wide range of support to a number of national and international missions, including command and control, mission management, data acquisition and routing, and environmental data processing and distribution. The current suite of CGS-supported missions has demonstrated the value of interagency and international partnerships to address global observation needs. With its established infrastructure and existing suite of missions, the CGS is extensible to a wider array of potential new missions. This paper will describe how the inherent scalability and extensibility of the CGS enables the addition of these new missions, with an eye on global enterprise needs in the 2020's and beyond.

  8. A blind reversible robust watermarking scheme for relational databases.

    Science.gov (United States)

    Chang, Chin-Chen; Nguyen, Thai-Son; Lin, Chia-Chen

    2013-01-01

    Protecting the ownership and controlling the copies of digital data have become very important issues in Internet-based applications. Reversible watermark technology allows the distortion-free recovery of relational databases after the embedded watermark data are detected or verified. In this paper, we propose a new, blind, reversible, robust watermarking scheme that can be used to provide proof of ownership for the owner of a relational database. In the proposed scheme, a reversible data-embedding algorithm, which is referred to as "histogram shifting of adjacent pixel difference" (APD), is used to obtain reversibility. The proposed scheme can detect successfully 100% of the embedded watermark data, even if as much as 80% of the watermarked relational database is altered. Our extensive analysis and experimental results show that the proposed scheme is robust against a variety of data attacks, for example, alteration attacks, deletion attacks, mix-match attacks, and sorting attacks.

  9. Reverse photoacoustic standoff spectroscopy

    Science.gov (United States)

    Van Neste, Charles W [Kingston, TN; Senesac, Lawrence R [Knoxville, TN; Thundat, Thomas G [Knoxville, TN

    2011-04-12

    A system and method are disclosed for generating a reversed photoacoustic spectrum at a greater distance. A source may emit a beam to a target and a detector measures signals generated as a result of the beam being emitted on the target. By emitting a chopped/pulsed light beam to the target, it may be possible to determine the target's optical absorbance by monitoring the intensity of light collected at the detector at different wavelengths. As the wavelength of light is changed, the target may absorb or reject each optical frequency. Rejection may increase the intensity at the sensing element and absorption may decrease the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

  10. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  11. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  12. Sex Reversal in Amphibians.

    Science.gov (United States)

    Flament, Stéphane

    2016-01-01

    Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing this process are reviewed. In the second part, the state of the art about sex reversal, which can be induced by steroid hormones in general and by temperature in some species, is presented. Also information about pollutants found in the environment that could interfere with the development of the amphibian reproductive apparatus or with their reproductive physiology is given. Such compounds could play a part in the amphibian decline, since in the wild, many amphibians are endangered species. © 2016 S. Karger AG, Basel.

  13. Turning an Extension Aide into an Extension Agent

    Science.gov (United States)

    Seevers, Brenda; Dormody, Thomas J.

    2010-01-01

    For any organization to remain sustainable, a renewable source of faculty and staff needs to be available. The Extension Internship Program for Juniors and Seniors in High School is a new tool for recruiting and developing new Extension agents. Students get "hands on" experience working in an Extension office and earn college credit…

  14. Initial ideas for automatic design and verification of control logic in reversible HDLs

    DEFF Research Database (Denmark)

    Wille, Robert; Keszocze, Oliver; Othmer, Lars

    2016-01-01

    not obvious. Moreover, implementations exist which may not be realized with a reversible control flow at all. In this work, we propose automatic methods for descriptions in the reversible HDL SyReC that can generate the required fi-conditions and check whether a reversible control flow indeed can be realized....... The envisioned solution utilizes predicate transformer semantics based on Hoare logic. The presented ideas constitute the first steps towards automatic methods for these important designs steps in the domain of reversible circuit design....

  15. Field reversal produced by a plasma gun

    International Nuclear Information System (INIS)

    Hartman, C.W.; Condit, W.; Granneman, E.H.A.; Prono, D.; Smith, A.C. Jr.; Taska, J.; Turner, W.C.

    1980-01-01

    Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode

  16. Reversed-field multiple mirror concept

    International Nuclear Information System (INIS)

    Steinhauer, L.C.; Grossmann, W.; Seyler, C.E.

    1978-01-01

    The reversed-field multiple mirror (RFMM), is a promising technique for end-stoppering linear magnetic fusion plasmas. By this means the physics and engineering advantages of a linear plasma are gained while circumventing the endloss problem, allowing the projection of very short (less than or equal to 100 m) conceptual reactors. RFMM end-stoppering is accomplished by a string of closed field-line cells on the plasma column axis; these cells strongly retard the axial flow of particles and energy. We describe the reactor implications of the RFMM

  17. Hypogenetic chaotic jerk flows

    International Nuclear Information System (INIS)

    Li, Chunbiao; Sprott, Julien Clinton; Xing, Hongyan

    2016-01-01

    Removing the amplitude or polarity information in the feedback loop of a jerk structure shows that special nonlinearities with partial information in the variable can also lead to chaos. Some striking properties are found for this kind of hypogenetic chaotic jerk flow, including multistability of symmetric coexisting attractors from an asymmetric structure, hidden attractors with respect to equilibria but with global attraction, easy amplitude control, and phase reversal which is convenient for chaos applications. - Highlights: • Hypogenetic chaotic jerk flows with incomplete feedback of amplitude or polarity are obtained. • Multistability of symmetric coexisting attractors from an asymmetric structure is found. • Some jerk systems have hidden attractors with respect to equilibria but have global attraction. • These chaotic jerk flows have the properties of amplitude control and phase reversal.

  18. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang

    2015-07-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  19. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang; Lavier, Luc L.; Choi, Eunseo

    2015-01-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  20. Waste pipe calculus extensions

    International Nuclear Information System (INIS)

    O'Connell, W.J.

    1979-01-01

    The waste pipe calculus provides a rapid method, using Laplace transforms, to calculate the transport of a pollutant such as nuclear waste, by a network of one-dimensional flow paths. The present note extends previous work as follows: (1) It provides an alternate approximation to the time-domain function (inverse Laplace transform) for the resulting transport. This algebraic approximation may be viewed as a simpler and more approximate model of the transport process. (2) It identifies two scalar quantities which may be used as summary consequence measures of the waste transport (or inversely, waste retention) system, and provides algebraic expressions for them. (3) It includes the effects of radioactive decay on the scalar quantity results, and further provides simplifying approximations for the cases of medium and long half-lives. This algebraic method can be used for quick approximate analyses of expected results, uncertainty and sensitivity, in evaluating selection and design choices for nuclear waste disposal systems

  1. Slowly switching between environments facilitates reverse evolution in small populations

    Science.gov (United States)

    Tan, Longzhi; Gore, Jeff

    2011-03-01

    The rate at which a physical process occurs usually changes the behavior of a system. In thermodynamics, the reversibility of a process generally increases when it occurs at an infinitely slow rate. In biological evolution, adaptations to a new environment may be reversed by evolution in the ancestral environment. Such fluctuating environments are ubiquitous in nature, although how the rate of switching affects reverse evolution is unknown. Here we use a computational approach to quantify evolutionary reversibility as a function of the rate of switching between two environments. For small population sizes, which travel on landscapes as random walkers, we find that both genotypic and phenotypic reverse evolution increase at slow switching rates. However, slow switching of environments decreases evolutionary reversibility for a greedy walker, corresponding to large populations (extensive clonal interference). We conclude that the impact of the switching rate for biological evolution is more complicated than other common physical processes, and that a quantitative approach may yield significant insight into reverse evolution.

  2. Reversible and irreversible heat engine and refrigerator cycles

    Science.gov (United States)

    Leff, Harvey S.

    2018-05-01

    Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

  3. Spacetime extensions II

    Energy Technology Data Exchange (ETDEWEB)

    Racz, Istvan, E-mail: iracz@rmki.kfki.h [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

    2010-08-07

    The global extendibility of smooth causal geodesically incomplete spacetimes is investigated. Denote by {gamma} one of the incomplete non-extendible causal geodesics of a causal geodesically incomplete spacetime (M, g{sub ab}). First, it is shown that it is always possible to select a synchronized family of causal geodesics {Gamma} and an open neighbourhood U of a final segment of {gamma} in M such that U comprises members of {Gamma}, and suitable local coordinates can be defined everywhere on U provided that {gamma} does not terminate either on a tidal force tensor singularity or on a topological singularity. It is also shown that if, in addition, the spacetime (M, g{sub ab}) is globally hyperbolic, and the components of the curvature tensor, and its covariant derivatives up to order k - 1 are bounded on U, and also the line integrals of the components of the kth-order covariant derivatives are finite along the members of {Gamma}-where all the components are meant to be registered with respect to a synchronized frame field on U-then there exists a C{sup k-} extension {Phi} : (M,g{sub ab}) {yields}(M,g{sub ab}) so that for each {gamma}-bar from {Gamma}, which is inextendible in (M, g{sub ab}), the image, {Phi}{gamma}-bar, is extendible in (M,g{sub ab}). Finally, it is also proved that whenever {gamma} does terminate on a topological singularity (M, g{sub ab}) cannot be generic.

  4. Web Extensible Display Manager

    Energy Technology Data Exchange (ETDEWEB)

    Slominski, Ryan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Larrieu, Theodore L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2018-02-01

    Jefferson Lab's Web Extensible Display Manager (WEDM) allows staff to access EDM control system screens from a web browser in remote offices and from mobile devices. Native browser technologies are leveraged to avoid installing and managing software on remote clients such as browser plugins, tunnel applications, or an EDM environment. Since standard network ports are used firewall exceptions are minimized. To avoid security concerns from remote users modifying a control system, WEDM exposes read-only access and basic web authentication can be used to further restrict access. Updates of monitored EPICS channels are delivered via a Web Socket using a web gateway. The software translates EDM description files (denoted with the edl suffix) to HTML with Scalable Vector Graphics (SVG) following the EDM's edl file vector drawing rules to create faithful screen renderings. The WEDM server parses edl files and creates the HTML equivalent in real-time allowing existing screens to work without modification. Alternatively, the familiar drag and drop EDM screen creation tool can be used to create optimized screens sized specifically for smart phones and then rendered by WEDM.

  5. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse gear...

  6. A Reverse Shock in GRB 160509A

    Science.gov (United States)

    Laskar, Tanmoy; Alexander, Kate D.; Berger, Edo; Fong, Wen-fai; Margutti, Raffaella; Shivvers, Isaac; Williams, Peter K. G.; Kopač, Drejc; Kobayashi, Shiho; Mundell, Carole; Gomboc, Andreja; Zheng, WeiKang; Menten, Karl M.; Graham, Melissa L.; Filippenko, Alexei V.

    2016-12-01

    We present the second multi-frequency radio detection of a reverse shock in a γ-ray burst. By combining our extensive radio observations of the Fermi-Large Area Telescope γ-ray burst 160509A at z = 1.17 up to 20 days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at ≲10 days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of {n}0≈ {10}-3 {{cm}}-3, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, N H ≈ 1.5 × 1022 {{cm}}-2, and a high rest-frame optical extinction, A V ≈ 3.4 mag. We identify a jet break in the X-ray light curve at {t}{jet}≈ 6 {days}, and thus derive a jet opening angle of {θ }{jet}≈ 4^\\circ , yielding a beaming-corrected kinetic energy and radiated γ-ray energy of {E}{{K}}≈ 4× {10}50 erg and {E}γ ≈ 1.3× {10}51 erg (1-104 keV, rest frame), respectively. Consistency arguments connecting the forward shocks and reverse shocks suggest a deceleration time of {t}{dec} ≈ 460 s ≈ T 90, a Lorentz factor of {{Γ }}({t}{dec})≈ 330, and a reverse-shock-to-forward-shock fractional magnetic energy density ratio of {R}{{B}}\\equiv {ɛ }{{B},{RS}}/{ɛ }{{B},{FS}}≈ 8. Our study highlights the power of rapid-response radio observations in the study of the properties and dynamics of γ-ray burst ejecta.

  7. Design extension conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bujor, A.; Harwood, C.; Lei, Q.; Viktorov, A., E-mail: christopher.harwood@cnsc-ccsn.gc.ca [Canadian Nuclear Safety Commission, Ottawa, Ontario (Canada)

    2013-07-01

    The CNSC has introduced the term Design Extension Conditions (DEC) in regulatory document RD-337 version 2, 'Design of New Nuclear Power Plants' which was issued for public consultation in July 2012. The primary drivers for this change compared with the earlier version of RD-337 are to maintain alignment with the equivalent International Atomic Energy Agency (IAEA) safety standard and to introduce changes resulting from lessons learned from the Fukushima Daiichi accident. RD-337 version 2 and the accompanying guidance document GD-337 establish high level design requirements and expectations for new Nuclear Power Plants (NPPs), including those pertaining to DEC. Other regulatory documents provide requirements for safety analysis and accident management as well as other aspect relevant to DEC. Nevertheless, the currently available guidance specific to DEC is not comprehensive, while the practices just begin to emerge. CNSC and industry stakeholders are actively discussing how the high level requirements and expectations will be applied in various fields. This paper is a summary of a CNSC discussion paper that is being developed to encourage substantive stakeholder discussions. The topic of DEC is being advanced rapidly both nationally and internationally. With this in mind, this paper does not intend to provide a final established position, but rather to stimulate discussion on the subject of DEC. This paper provides the definition of DEC, gives background information relating to the adoption of the term, describes the identification of DECs and the underlying principles associated with design, analysis, operational and procedural requirements. As described in this paper, DEC and associated requirements apply to new NPPs. Applicability to existing NPPs is also discussed. (author)

  8. A Classification of BPEL Extensions

    Directory of Open Access Journals (Sweden)

    Oliver Kopp

    2011-10-01

    Full Text Available The Business Process Execution Language (BPEL has emerged as de-facto standard for business processes implementation. This language is designed to be extensible for including additional valuable features in a standardized manner. There are a number of BPEL extensions available. They are, however, neither classified nor evaluated with respect to their compliance to the BPEL standard. This article fills this gap by providing a framework for classifying BPEL extensions, a classification of existing extensions, and a guideline for designing BPEL extensions.

  9. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    Linford, R.K.; Armstrong, W.T.; Platts, D.A.; Sherwood, E.G.

    1978-01-01

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centers the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFC's with a major radius R = 2-6 cm, minor radius a approximately 2 cm, and a total length l approximately 35 cm. The observed temperatures are T/sub e/ approximately 100 eV and T/sub i/ = 150-350 eV with a peak density n approximately 2 x 10 15 cm -3 . After the plasma reaches equilibrium, the RFC remains stable for up to 30 μs followed by the rapid growth of the rotational m = 2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behavior of the m = 2 mode qualitatively agrees with the theoretically predicted instability for rotational velocities exceeding some critical value

  10. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    Linford, R.K.; Armstrong, W.T.; Platts, D.A.; Sherwood, E.G.

    1979-01-01

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centres the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFCs with a major radius R=2-6cm, a minor radius a approximately 2cm, and a total length l approximately 35cm. The observed temperatures are Tsub(e) approximately 100eV and Tsub(i)=150-350eV with a peak density n approximately 2x10 15 cm -3 . After the plasma has reached equilibrium, the RFC remains stable for up to 30μs, followed by the rapid growth of the rotational m=2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behaviour of the m=2 mode agrees qualitatively with the theoretically predicted instability for rotational velocities exceeding some critical value. (author)

  11. Reversal of multidrug resistance by surfactants.

    Science.gov (United States)

    Woodcock, D. M.; Linsenmeyer, M. E.; Chojnowski, G.; Kriegler, A. B.; Nink, V.; Webster, L. K.; Sawyer, W. H.

    1992-01-01

    Cremophor EL, a pharmacologically inactive solubilising agent, has been shown to reverse multidrug resistance (MDR). Using flow cytometric evaluation of equilibrium intracellular levels of daunorubicin (DNR), we found that eight other surface active agents will also reverse MDR. All the active detergents contain polyethoxylated moieties but have no similarities in their hydrophobic components. The properties of three polyethoxylated surfactants that showed the lowest toxicities, Cremophor, Tween 80 and Solutol HS15, were examined in more detail. The concentrations of Tween 80 and Solutol required to reverse DNR exclusion were 10-fold lower than for Cremophor. However while concentrations greater than or equal to 1:10(2) of the former two surfactants resulted in breakdown of cells, even 1:10 of Cremophor did not lyse cells. Studies of the effects of Cremophor on the uptake and efflux of DNR in normal and MDR cell types showed that Cremophor increases intracellular DNR primarily by locking the rapid efflux from the cells. This blockage of drug efflux may be mediated by a substantial alteration in the fluidity of cell membranes induced by Cremophor, as shown by decreased fluorescence anisotropy of a membrane probe. Consistent with these data, coinjection of adriamycin plus Cremophor into mice carrying a multidrug resistant P388 transplantable tumour significantly increased the survival time of the mice compared with adriamycin treatment alone. PMID:1637678

  12. Early detection of preferential channeling in reverse electrodialysis

    NARCIS (Netherlands)

    Vermaas, David; Saakes, Michel; Nijmeijer, Dorothea C.

    2014-01-01

    Membrane applications often experience fouling, which prevent uniform flow distribution through the feed water compartments, i.e. preferential channeling may occur. This research shows the effect of preferential channeling on energy generation from mixing salt water and fresh water using reverse

  13. Quickly erupted volcanic sections of the Steens Basalt, Columbia River Basalt Group: Secular variation, tectonic rotation, and the Steens Mountain reversal

    Science.gov (United States)

    Jarboe, Nicholas A.; Coe, Robert S.; Renne, Paul R.; Glen, Jonathan M. G.; Mankinen, Edward A.

    2008-01-01

    The Steens Basalt, now considered part of the Columbia River Basalt Group (CRBG), contains the earliest eruptions of this magmatic episode. Lava flows of the Steens Basalt cover about 50,000 km2 of the Oregon Plateau in sections up to 1000 m thick. The large number of continuously exposed, quickly erupted lava flows (some sections contain over 200 flows) allows for small loops in the magnetic field direction paths to be detected. For volcanic rocks, this detail and fidelity are rarely found outside of the Holocene and yield estimates of eruption durations at our four sections of ∼2.5 ka for 260 m at Pueblo Mountains, 0.5 to 1.5 ka for 190 m at Summit Springs, 1–3 ka for 170 m at North Mickey, and ∼3 ka for 160 m at Guano Rim. That only one reversal of the geomagnetic field occurred during the eruption of the Steens Basalt (the Steens reversal at approximately 16.6 Ma) is supported by comparing 40Ar/39Ar ages and magnetic polarities to the geomagnetic polarity timescale. At Summit Springs two 40Ar/39Ar ages from normal polarity flows (16.72 ± ± 0.29 Ma (16.61) and 16.92 ± ± 0.52 Ma (16.82); ± ± equals 2σ error) place their eruptions after the Steens reversal, while at Pueblo Mountains an 40Ar/39Ar age of 16.72 ± ± 0.21 Ma (16.61) from a reverse polarity flow places its eruption before the Steens reversal. Paleomagnetic field directions yielded 50 nontransitional directional-group poles which, combined with 26 from Steens Mountain, provide a paleomagnetic pole for the Oregon Plateau of 85.7°N, 318.4°E, K = 15.1, A95 = 4.3. Comparison of this new pole with a reference pole derived from CRBG flows from eastern Washington and a synthetic reference pole for North America derived from global data implies relative clockwise rotation of the Oregon Plateau of 7.4 ± 5.0° or 14.5 ± 5.4°, respectively, probably due to northward decreasing extension of the basin and range.

  14. Towards a reversible functional language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    /equality operator also simplifies inverse computation and program inversion. We discuss the advantages of a reversible functional language using example programs, including run-length encoding. Program inversion is seen to be as lightweight as for imperative reversible languages and realized by recursive descent...

  15. Reverse engineering of RFID devices

    NARCIS (Netherlands)

    Bokslag, W.

    2015-01-01

    This paper discusses the relevance and potential impact of both RFID and reverse engineering of RFID technology, followed by a discussion of common protocols and internals of RFID technology. The focus of the paper is on providing an overview of the different approaches to reverse engineering RFID

  16. How decision reversibility affects motivation

    NARCIS (Netherlands)

    Bullens, L.; van Harreveld, F.; Förster, J.; Higgins, T.E.

    2014-01-01

    The present research examined how decision reversibility can affect motivation. On the basis of extant findings, it was suggested that 1 way it could affect motivation would be to strengthen different regulatory foci, with reversible decision making, compared to irreversible decision making,

  17. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.
    In Chapter 1 the present knowledge about reversed micelles and

  18. Reversible networks in supramolecular polymers

    NARCIS (Netherlands)

    Havermans - van Beek, D.J.M.

    2007-01-01

    Non–covalent interactions between low molecular weight polymers form the basis of supramolecular polymers. The material properties of such polymers are determined by the strength and lifetime of the non–covalent reversible interactions. Due to the reversibility of the interactions between the low

  19. Reverse genetics of avian metapneumoviruses

    Science.gov (United States)

    An overview of avian metapneumovirus (aMPV) infection in turkeys and development of a reverse genetics system for aMPV subgroup C (aMPV-C) virus will be presented. By using reverse genetics technology, we generated recombinant aMPV-C viruses containing a different length of glycoprotein (G) gene or...

  20. A model for 'reverse innovation' in health care.

    Science.gov (United States)

    Depasse, Jacqueline W; Lee, Patrick T

    2013-08-30

    'Reverse innovation,' a principle well established in the business world, describes the flow of ideas from emerging to more developed economies. There is strong and growing interest in applying this concept to health care, yet there is currently no framework for describing the stages of reverse innovation or identifying opportunities to accelerate the development process. This paper combines the business concept of reverse innovation with diffusion of innovation theory to propose a model for reverse innovation as a way to innovate in health care. Our model includes the following steps: (1) identifying a problem common to lower- and higher-income countries; (2) innovation and spread in the low-income country (LIC); (3) crossover to the higher-income country (HIC); and (4) innovation and spread in the HIC. The crucial populations in this pathway, drawing from diffusion of innovation theory, are LIC innovators, LIC early adopters, and HIC innovators. We illustrate the model with three examples of current reverse innovations. We then propose four sets of specific actions that forward-looking policymakers, entrepreneurs, health system leaders, and researchers may take to accelerate the movement of promising solutions through the reverse innovation pipeline: (1) identify high-priority problems shared by HICs and LICs; (2) create slack for change, especially for LIC innovators, LIC early adopters, and HIC innovators; (3) create spannable social distances between LIC early adopters and HIC innovators; and (4) measure reverse innovation activity globally.

  1. MODELS OF PROJECT REVERSE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Віктор Володимирович ІВАНОВ

    2017-03-01

    Full Text Available Reverse engineering decided important scientific and technical problems of increasing the cost of the existing technical product by transforming it into a product with other features or design. Search ideas of the new application of existing products on the base of heuristic analysis were created. The concept of reverse engineering and its division into three types: conceptual, aggregate and complete was expanded. The use of heuristic methods for reverse engineering concept was showed. The modification model of Reverse engineering based on the model of РМВОК was developed. Our model includes two new phases: identification and transformation. At the identification phase, technical control is made. At the transformation phase, search heuristic idea of the new applied existing technical product was made. The model of execution phase that included heuristic methods, metrological equipment, and CAD/CAM/CAE program complex was created. The model that connected economic indicators of reverse engineering project was developed.

  2. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should...... are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...

  3. The Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, James R.

    2003-01-01

    By modifying the IGRF it is possible to learn what may happen to the geomagnetic field during a geomagnetic reversal. If the entire IGRF reverses then the declination and inclination only reverse when the field strength is zero. If only the dipole component of the IGRF reverses a large geomagnetic field remains when the dipole component is zero and he direction of the field at the end of the reversal is not exactly reversed from the directions at the beginning of the reversal.

  4. Do the cerebellar tonsils move during flexion and extension of the neck in patients with Chiari I malformation? A radiological study with clinical implications.

    Science.gov (United States)

    Tubbs, R Shane; Kirkpatrick, Christina M; Rizk, Elias; Chern, Joshua J; Oskouian, Rod J; Oakes, W Jerry

    2016-03-01

    In the past, diagnosis of the Chiari I malformation has primarily been made on midsagittal MRI. We hypothesized that based on the frequent presentation of opisthotonos in patients with hindbrain hernia (primarily Chiari II malformation but sometimes Chiari I malformation) that the hyperextension might be a compensatory technique used by such patients to bring the cerebellar tonsils up out of the cervical spine. This prospective study reviewed imaging of patients with Chiari I malformation who underwent flexion/extension MRI for evaluation of their hindbrain herniation. Age-matched controls were used for comparison. In general, there was elevation of the cerebellar tonsils with extension and increased descent with flexion of the cervical spine. In 72 % of patients, flexion of the neck resulted in descent of the cerebellar tonsils. In 64 % of patients, extension of the neck resulted in ascent of the cerebellar tonsils. In the 14 patients with an associated syrinx, 71 % were found to have caudal movement of the cerebellar tonsils with neck flexion, and only 43 % were observed to have any movement of the cerebellar tonsils in neck extension compared to patients without a syrinx where ascent of the tonsils was seen in only nine during neck extension. Two patients were observed to have the reverse finding of ascent of the cerebellar tonsils with neck flexion and descent of the cerebellar tonsils with neck extension. Five patients had no movement of the cerebellar tonsils in either flexion or extension of the neck, and one of these had a small syrinx. Although minimal and not in all patients, we observed elevation of the herniated cerebellar tonsils with extension of the cervical spine in patients with Chiari I malformation. This finding provides evidence as to why some patients with hindbrain herniation present with opisthotonos and supports earlier findings that CSF flow is reduced at the craniocervical junction in flexion in patients with Chiari I malformation.

  5. Closing the Loop : Reverse supply chain management andproduct return processes in electronics retailing

    OpenAIRE

    Gorskova, Julija; Ortega, Edrion

    2012-01-01

    Abstract Problem There is a gap in the knowledge concerning reverse product flows due to a lack of research and empirical data in the field of reverse supply chain management in general. Furthermore, more research is needed to investigate the factors influencing the decision making process regarding the right reverse supply chain recovery option choice for companies in order to close the supply chain loop. Processing product returns has become a critical activity for organisations as the volu...

  6. How decision reversibility affects motivation.

    Science.gov (United States)

    Bullens, Lottie; van Harreveld, Frenk; Förster, Jens; Higgins, Tory E

    2014-04-01

    The present research examined how decision reversibility can affect motivation. On the basis of extant findings, it was suggested that 1 way it could affect motivation would be to strengthen different regulatory foci, with reversible decision making, compared to irreversible decision making, strengthening prevention-related motivation relatively more than promotion-related motivation. If so, then decision reversibility should have effects associated with the relative differences between prevention and promotion motivation. In 5 studies, we manipulated the reversibility of a decision and used different indicators of regulatory focus motivation to test these predictions. Specifically, Study 1 tested for differences in participants' preference for approach versus avoidance strategies toward a desired end state. In Study 2, we used speed and accuracy performance as indicators of participants' regulatory motivation, and in Study 3, we measured global versus local reaction time performance. In Study 4, we approached the research question in a different way, making use of the value-from-fit hypothesis (Higgins, 2000, 2002). We tested whether a fit between chronic regulatory focus and focus induced by the reversibility of the decision increased participants' subjective positive feelings about the decision outcome. Finally, in Study 5, we tested whether regulatory motivation, induced by decision reversibility, also influenced participants' preference in specific product features. The results generally support our hypothesis showing that, compared to irreversible decisions, reversible decisions strengthen a prevention focus more than a promotion focus. Implications for research on decision making are discussed.

  7. Think - Baltic Extension / Kalle Kask

    Index Scriptorium Estoniae

    Kask, Kalle

    2002-01-01

    Tallinna TÜ Rehabilitatsiooni tehnoloogia keskus korraldas pressikonverentsi, kus tutvustati osalemist EL V raamprogrammis Think - Baltic Extension, mis on suunatud puuetega inimeste tööhõive tagamisele

  8. Robotic hand with modular extensions

    Science.gov (United States)

    Salisbury, Curt Michael; Quigley, Morgan

    2015-01-20

    A robotic device is described herein. The robotic device includes a frame that comprises a plurality of receiving regions that are configured to receive a respective plurality of modular robotic extensions. The modular robotic extensions are removably attachable to the frame at the respective receiving regions by way of respective mechanical fuses. Each mechanical fuse is configured to trip when a respective modular robotic extension experiences a predefined load condition, such that the respective modular robotic extension detaches from the frame when the load condition is met.

  9. Streaming reversal of energetic particles in the magnetotail during a substorm

    Science.gov (United States)

    Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

    1984-01-01

    A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

  10. OpenFlow Extensions for Programmable Quantum Networks

    Science.gov (United States)

    2017-06-19

    Introduction 1 2. Background 1 2.1 Quantum Networks 2 2.2 Software -Defined Networks 3 3. Approach 3 3.1 Metadata 4 3.2 Switch 4 3.3 Controller 5... software -defined networks . Stanford (CA): Stanford University HotNets; 2010. 9. Raychev N. Algorithm for switching 4-bit packages in full quantum...applications to communicate. Advances in network protocols and architectures have led to the development of software -defined programmable networks

  11. Extensions of Fundamental Flow Physics to Practical MAV Aerodynamics

    Science.gov (United States)

    2016-05-01

    of rotation, akin to the Magnus effect : = 2 4 ?̇? Then we obtain the above lift contribution by applying ∞. To this we...drag. Differences in circulatory lift are primarily a steady offset and not a slope change, and are ascribable to the “ Magnus effect ”. t’ C L 0 2 4...plunge are mutually irreconcilable, owing to the aforementioned Magnus effect of pitch-rate. The pitching case has much higher lift and drag than does

  12. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  13. Reverse engineering for quality systems

    International Nuclear Information System (INIS)

    Nolan, A.J.

    1995-01-01

    When the age of software engineering began, many companies were faced with a problem of how to support the older, pre-software-engineering, programs. The techniques of reverse engineering and re-engineering were developed to bridge the gap between the past and the present. Although reverse engineering can be used for generating missing documentation, it can also be used as a means to demonstrate quality in these older programs. This paper presents, in the form of a case study, how Rolls-Royce and Associates Limited addressed the quality issues of reverse engineering and re-engineering. (author)

  14. Field reversal in mirror machines

    International Nuclear Information System (INIS)

    Pearlstein, L.D.; Anderson, D.V.; Boozer, A.H.

    1978-01-01

    This report discusses some of the physics issues anticipated in field-reversed mirrors. The effect of current cancellation due to electrons is described. An estimate is made of the required impurity level to maintain a field-reversed configuration. The SUPERLAYER code is used to simulate the high-β 2XIIB results, and favorable comparisons require inclusion of quasilinear RF turbulence. Impact of a quadrupole field on field-line closure and resonant transport is discussed. A simple self-consistent model of ion currents is presented. Conditions for stability of field-reversed configurations to E x B driven rotations are determined

  15. Centrifugal compressor tip clearance and impeller flow

    Energy Technology Data Exchange (ETDEWEB)

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

    2016-11-15

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

  16. Centrifugal compressor tip clearance and impeller flow

    International Nuclear Information System (INIS)

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

    2016-01-01

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

  17. Zero field reversal probability in thermally assisted magnetization reversal

    Science.gov (United States)

    Prasetya, E. B.; Utari; Purnama, B.

    2017-11-01

    This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

  18. abc: An Extensible AspectJ Compiler

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie J.

    2006-01-01

    checking and code generation, as well as data flow and control flow analyses. The AspectBench Compiler (abc) is an implementation of such a workbench. The base version of abc implements the full AspectJ language. Its front end is built using the Polyglot framework, as a modular extension of the Java...... language. The use of Polyglot gives flexibility of syntax and type checking. The back end is built using the Soot framework, to give modular code generation and analyses. In this paper, we outline the design of abc, focusing mostly on how the design supports extensibility. We then provide a general...

  19. The Reverse Supply Chain: Configuration, Integration and Profitability

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2008-01-01

    This thesis presents the results of a qualitative investigation that has been conducted in order to enhance knowledge of the reverse supply chain management field. Two aspects of the reverse flow need to be taken into consideration: the importance of introducing mechanisms that promote the circui......This thesis presents the results of a qualitative investigation that has been conducted in order to enhance knowledge of the reverse supply chain management field. Two aspects of the reverse flow need to be taken into consideration: the importance of introducing mechanisms that promote...... the circuitry of resources in order to protect the environment, and the increasing awareness that if strategically managed, the reverse chain represents an opportunity for profit generation and for improving the competitive position of a firm. In the first case, the main stakeholders are represented...... within the 27 Member States, reaching approximately 14-24 Kg. per inhabitant in Western Europe and the 6-12 Kg. per inhabitant in the New Member States. In the second case, the main stakeholder is the firm, the producer that has the possibility of exploring new opportunities to achieve a competitive...

  20. Thaw flow control for liquid heat transport systems

    Science.gov (United States)

    Kirpich, Aaron S.

    1989-01-01

    In a liquid metal heat transport system including a source of thaw heat for use in a space reactor power system, the thaw flow throttle or control comprises a fluid passage having forward and reverse flow sections and a partition having a plurality of bleed holes therein to enable fluid flow between the forward and reverse sections. The flow throttle is positioned in the system relatively far from the source of thaw heat.

  1. Repeat Customer Success in Extension

    Science.gov (United States)

    Bess, Melissa M.; Traub, Sarah M.

    2013-01-01

    Four multi-session research-based programs were offered by two Extension specialist in one rural Missouri county. Eleven participants who came to multiple Extension programs could be called "repeat customers." Based on the total number of participants for all four programs, 25% could be deemed as repeat customers. Repeat customers had…

  2. Frames and extension problems I

    DEFF Research Database (Denmark)

    Christensen, Ole

    2014-01-01

    In this article we present a short survey of frame theory in Hilbert spaces. We discuss Gabor frames and wavelet frames and set the stage for a discussion of various extension principles; this will be presented in the article Frames and extension problems II (joint with H.O. Kim and R.Y. Kim)....

  3. Why Do Extension Agents Resign?

    Science.gov (United States)

    Manton, Linda Nunes; van Es, J. C.

    1985-01-01

    Past and current Illinois extension agents were surveyed via mail questionnaires as to reasons for staying or leaving extension programs. Reasons for leaving included family changes, family moves, opportunity to advance, better salary/benefits, dissatisfaction with administration, and too much time away from family. (CT)

  4. Quotient semigroups and extension semigroups

    Indian Academy of Sciences (India)

    Introduction. Abelian groups and semigroups play an important role in the classification of C. ∗. -algebras and their extensions. ... -algebra extension theory and K K-theory, it is crucial to study the theory of quotient semigroups from the ...

  5. Universal extensions to simulate specifications

    NARCIS (Netherlands)

    Hesselink, Wim H.

    A previous paper introduced eternity variables as an alternative to the prophecy variables of Abadi and Lamport and proved the formalism to be semantically complete: every simulation F. K -> L that preserves quiescence contains a composition of a history extension, an extension with eternity

  6. Flow in data racks

    Directory of Open Access Journals (Sweden)

    Manoch Lukáš

    2014-03-01

    Full Text Available This paper deals with the flow in data racks. The aim of this work is to find a new arrangement of elements regulating the flow in the data rack so that the aerodynamic losses and the recirculation zones were minimized. The main reason for solving this problem is to reduce the costs of data racks cooling. Another problem to be solved is a reverse flow in the servers, thus not cooled, occuring due to the underpressure in the recirculation zones. In order to solve the problem, the experimental and numerical model of 27U data rack fitted with 10 pieces of server models with a total input of 10 kW was created. Different configurations of layout of elements affecting the flow in the inlet area of the data rack were compared. Depending on the results achieved, design solutions for the improvement of existing solutions were adopted and verified by numerical simulations.

  7. Spontaneous direct and reverse osmosis

    International Nuclear Information System (INIS)

    Valitov, N.Kh.

    1996-01-01

    It has been ascertained experimentally that in the course of separation of CsCl, KCl, NaCl aqueous solutions by semi-permeable membrane from distilled water the direct and then reverse osmosis are observed. The same sequence is observed in case of separation of CsCl aqueous solutions from NaCl of different concentrations. The reason for the direct and reverse osmosis has been explained. 5 refs.; 3 figs. 1 tab

  8. Buoyancy-driven flow excursions in fuel assemblies

    International Nuclear Information System (INIS)

    Laurinat, J.E.; Paul, P.K.; Menna, J.D.

    1995-01-01

    A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating heavy water moderator downward through channels in cylindrical fuel tubes. Powers were limited to safeguard against a flow excursion in one of more of these parallel channels. During-full-power operation, limits safeguarded against a boiling flow excursion. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increased beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of the limiting power for previous long-term reactor operations

  9. Buoyancy-driven flow excursions in fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, J.E.; Paul, P.K.; Menna, J.D. [Westinghouse Savannah River Company, Aiken, SC (United States)

    1995-09-01

    A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating heavy water moderator downward through channels in cylindrical fuel tubes. Powers were limited to safeguard against a flow excursion in one of more of these parallel channels. During-full-power operation, limits safeguarded against a boiling flow excursion. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increased beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of the limiting power for previous long-term reactor operations.

  10. Buoyancy-driven flow excursions in fuel assemblies

    International Nuclear Information System (INIS)

    Laurinat, J.E.; Paul, P.K.; Menna, J.D.

    1995-01-01

    A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating moderator downward through channels in cylindrical fuel tubes. Powers were limited to prevent a flow excursion from occurring in one or more of these parallel channels. During full-power operation, limits prevented a boiling flow excursion from taking place. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increases beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of historical levels

  11. Reverse convection in helium and other fluids in the high speed rotating frame: negative and positive buoyancy effects

    International Nuclear Information System (INIS)

    Igra, R.; Scurlock, R.G.; Wu, Y.Y.

    1986-01-01

    Experimental studies of thermo-syphon flows in radial tubes and loops between the axis and the periphery of a rotating helium cryostat have shown that when heat is supplied at an intermediate radius, the heat is carried radially inwards as A flow and radially outwards as B flow. The results with helium suggest that while the steady state patterns of the A and B flows are complex, the heat is divided approximately equally between the conventional A flow and the reverse B flow. A model of convective heating in the rotating frame is presented and two necessary conditions for reverse convection are identified and discussed. The model predicts reverse convection in liquid nitrogen and this is confirmed by experimental measurement. An array of radial ducts is proposed for the cooling of a superconducting AC generator in order to counter the effects of reverse convection in the helium refrigerant

  12. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used...

  13. Fingerprinting Reverse Proxies Using Timing Analysis of TCP Flows

    Science.gov (United States)

    2013-09-01

    Message Protocol IG Information Grid IP Internet Protocol ISP Internet Service Provider IT Information Technology MITM Man-in-the-middle NAT Network...Unsuspecting users could be vulnerable to man-in-the-middle ( MITM ) attacks or web-based attacks [2] against web browsers and browser plug-ins. There is no

  14. Sedimentology, Behavior, and Hazards of Debris Flows at Mount Rainier, Washington

    Science.gov (United States)

    Scott, K.M.; Vallance, J.W.; Pringle, P.T.

    1995-01-01

    Mount Rainier is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Many debris flows and their distal phases have inundated areas far from the volcano during postglacial time. Two types of debris flows, cohesive and noncohesive, have radically different origins and behavior that relate empirically to clay content. The two types are the major subpopulations of debris flows at Mount Rainier. The behavior of cohesive flows is affected by the cohesion and adhesion of particles; noncohesive flows are dominated by particle collisions to the extent that particle cataclasis becomes common during near-boundary shear. Cohesive debris flows contain more than 3 to 5 percent of clay-size sediment. The composition of these flows changed little as they traveled more than 100 kilometers from Mount Rainier to inundate parts of the now-populated Puget Sound lowland. They originate as deep-seated failures of sectors of the volcanic edifice, and such failures are sufficiently frequent that they are the major destructional process of Mount Rainier's morphologic evolution. In several deposits of large cohesive flows, a lateral, megaclast-bearing facies (with a mounded or hummocky surface) contrasts with a more clay-rich facies in the center of valleys and downstream. Cohesive flows at Mount Rainier do not correlate strongly with volcanic activity and thus can recur without warning, possibly triggered by non-magmatic earthquakes or by changes in the hydrothermal system. Noncohesive debris flows contain less than 3 to 5 percent clay-size sediment. They form most commonly by bulking of sediment in water surges, but some originate directly or indirectly from shallow slope failures that do not penetrate the hydrothermally altered core of the volcano. In contrast with cohesive flows, most noncohesive flows transform both from and to other flow types and are, therefore, the

  15. Journal of Agricultural Extension submitted to Agricultural Extension ...

    African Journals Online (AJOL)

    PROF. MADUKWE

    ... typically confront narrower range of labour markets than men, and lower wage ... capabilities of women and by extension the household, female household ..... gap in accessibility to productive resources between male and female heads of.

  16. Learning Joomla! 3 extension development

    CERN Document Server

    Plummer, Tim

    2013-01-01

    A practical guide with step-by-step examples that build on each other so you can learn by doing and get hands-on knowledge about creating your plugins, modules, and components in Joomla.""Learning Joomla! 3 Extension Development, Third Edition"" is for developers who want to create their own Joomla extensions. It is assumed you will have some basic PHP, HTML, and CSS knowledge, but you don't need any prior Joomla programming experience. This book will also be useful to people who just want to make minor customizations to existing Joomla extensions and build on the work of others in the open so

  17. Programming Reactive Extensions and LINQ

    CERN Document Server

    Liberty, Jesse

    2011-01-01

    Pro Reactive Extensions and LINQ is a deep dive into the next important technology for .NET developers: Reactive Extensions. This in-depth tutorial goes beyond what is available anywhere else to teach how to write WPF, Silverlight, and Windows Phone applications using the Reactive Extensions (Rx) to handle events and asynchronous method calls. Reactive programming allows you to turn those aspects of your code that are currently imperative into something much more event-driven and flexible. For this reason, it's sometimes referred to as LINQ for Events. Reactive programming hinges on the concep

  18. Extensions of the Standard Model

    CERN Document Server

    Zwirner, Fabio

    1996-01-01

    Rapporteur talk at the International Europhysics Conference on High Energy Physics, Brussels (Belgium), July 27-August 2, 1995. This talk begins with a brief general introduction to the extensions of the Standard Model, reviewing the ideology of effective field theories and its practical implications. The central part deals with candidate extensions near the Fermi scale, focusing on some phenomenological aspects of the Minimal Supersymmetric Standard Model. The final part discusses some possible low-energy implications of further extensions near the Planck scale, namely superstring theories.

  19. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  20. LASL toroidal reversed-field pinch programme

    International Nuclear Information System (INIS)

    Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

    1979-01-01

    The determination of the absolute energy loss due to radiation from impurities in the LASL toroidal reversed-field pinch experiment ZT-S is reported. The measurements show that over half the energy loss is accounted for by this mechanism. Thomson-scattering electron density measurements indicate only a gradual increase in temperature as the filling pressure is reduced, indicating an increased energy loss at lower pressures. Cylindrical and toroidal simulations of the experiment indicate either that a highly radiative pinch boundary or anomalous transport is needed to match the experimental results. New effects on the equilibrium due to plasma flows induced by the toroidal geometry are predicted by the toroidal simulations. The preliminary results on the low-temperature discharge cleaning of the ZT-S torus are reported. A description of the upgrade of the ZT-S experiment and the objectives, construction and theoretical predictions for the new ZT-40 experiment are given. (author)

  1. LASL toroidal reversed-field pinch program

    International Nuclear Information System (INIS)

    Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

    1978-01-01

    The determination of the absolute energy loss due to radiation from impurities in the LASL toroidal reversed-field pinch experiment ZT-S is reported. The measurements show over half of the energy loss is accounted for by this mechanism. Thomson scattering electron density measurements indicate only a gradual increase in temperature as the filling pressure is reduced indicating an increased energy loss at lower pressures. Cylindrical and toroidal simulations of the experiment indicate either that a highly radiative pinch boundary or anomalous transport are needed to match the experimental results. New effects on the equilibrium due to plasma flows induced by the toroidal geometry are predicted by the toroidal simulations. The preliminary results on the low temperature discharge cleaning of the ZT-S torus are reported. A description of the upgrade of the ZT-S experiment and the objectives, construction and theoretical predictions for the new ZT-40 experiment are given

  2. Research-extension-farmer linkages

    African Journals Online (AJOL)

    agricultural research and extension services, Government in 1990 set up a number of ... charged with the role of articulating the most appropriate research and ... production of 1800 copies of NARO bulletin, 1000 copies of Uganda Journal of ...

  3. Journal of Environmental Extension: Submissions

    African Journals Online (AJOL)

    Journal of Environmental Extension is purely academic and accepts positional or ... and so responsibility for the content and macro formatting remain of the author. ... For research articles, the methodology, result analysis (statistical tests to be ...

  4. Vasectomy reversal: a clinical update

    Directory of Open Access Journals (Sweden)

    Abhishek P Patel

    2016-01-01

    Full Text Available Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

  5. Boiler-turbine life extension

    Energy Technology Data Exchange (ETDEWEB)

    Natzkov, S. [TOTEMA, Ltd., Sofia (Bulgaria); Nikolov, M. [CERB, Sofia (Bulgaria)

    1995-12-01

    The design life of the main power equipment-boilers and turbines is about 105 working hours. The possibilities for life extension are after normatively regulated control tests. The diagnostics and methodology for Boilers and Turbines Elements Remaining Life Assessment using up to date computer programs, destructive and nondestructive control of metal of key elements of units equipment, metal creep and low cycle fatigue calculations. As well as data for most common damages and some technical decisions for elements life extension are presented.

  6. Flow-throttling orifice nozzle

    International Nuclear Information System (INIS)

    Sletten, H.L.

    1975-01-01

    A series-parallel-flow type throttling apparatus to restrict coolant flow to certain fuel assemblies of a nuclear reactor is comprised of an axial extension nozzle of the fuel assembly. The nozzle has a series of concentric tubes with parallel-flow orifice holes in each tube. Flow passes from a high pressure plenum chamber outside the nozzle through the holes in each tube in series to the inside of the innermost tube where the coolant, having dissipated most of its pressure, flows axially to the fuel element. (U.S.)

  7. Big bang in a universe with infinite extension

    Energy Technology Data Exchange (ETDEWEB)

    Groen, Oeyvind [Oslo College, Department of Engineering, PO Box 4, St Olavs Pl, 0130 Oslo (Norway); Institute of Physics, University of Oslo, PO Box 1048 Blindern, 0316 Oslo (Norway)

    2006-05-01

    How can a universe coming from a point-like big bang event have infinite spatial extension? It is shown that the relativity of simultaneity is essential in answering this question. Space is finite as defined by the simultaneity of one observer, but it may be infinite as defined by the simultaneity of all the clocks participating in the Hubble flow.

  8. Big bang in a universe with infinite extension

    International Nuclear Information System (INIS)

    Groen, Oeyvind

    2006-01-01

    How can a universe coming from a point-like big bang event have infinite spatial extension? It is shown that the relativity of simultaneity is essential in answering this question. Space is finite as defined by the simultaneity of one observer, but it may be infinite as defined by the simultaneity of all the clocks participating in the Hubble flow

  9. The treatment of radioactive aqueous wastes by reverse osmosis

    International Nuclear Information System (INIS)

    Hodgson, T.D.

    Experiments were carried out to determine the rejection factors for the more important radionuclides found in aqueous wastes, to study activity deposition within reverse osmosis modules, and to obtain experience in active operation of a reverse osmosis facility. It was found that reverse osmosis is likely to be useful in aqueous radioactive waste treatment when a wide range of contaminants rather than a specific radioactive species must be removed. There appeared to be no barrier to active operation, although greater confidence in the reliability of pumps and membranes is needed. The rejection of trace quantities of radioisotopes such as Cs + or Sr ++ could be predicted from the behaviour of similar inactive ions. Activity present as polyvalent ions or colloidal aggregates is highly rejected by the membrane. Activity may be deposited onto the membrane with insoluble or scaling compounds, and is greatest on areas of the membrane shielded from the sweeping action of the liquor flow

  10. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    a positive correlation with the extent of reverse knowledge transfers to the parent MNE. Relying on the headquarters-subsidiary view of the MNE, we argue that, beyond a point, increasing subsidiary innovativeness will be associated with lower reverse knowledge transfers. Further, we argue......It is now well recognized that multinational enterprises (MNEs) are differentiated networks wherein subsidiaries vary in terms of their ability to create new knowledge and competencies for their parent groups. In much of this theory, it is taken for granted that subsidiary innovativeness has...... that this relationship is sensitive to the subsidiary entry mode. Using data from a sample of 293 Italian subsidiaries, we find strong support for our hypotheses. In particular, our results confirm that the effect of subsidiary innovativeness on reverse knowledge transfers displays an inverted-U shape...

  11. Ice ages and geomagnetic reversals

    Science.gov (United States)

    Wu, Patrick

    1992-01-01

    There have been speculations on the relationship between climatic cooling and polarity reversals of the earth's magnetic field during the Pleistocene. Two of the common criticisms on this relationship have been the reality of these short duration geomagnetic events and the accuracy of their dates. Champion et al. (1988) have reviewed recent progress in this area. They identified a total of 10 short-duration polarity events in the last 1 Ma and 6 of these events have been found in volcanic rocks, which also have K-Ar dates. Supposing that the speculated relationship between climatic cooling and geomagnetic reversals actually exist, two mechanisms that assume climatic cooling causes short period magnetic reversals will be investigated. These two methods are core-mantle boundary topography and transfer of the rotational energy to the core.

  12. Reverse Transfection Using Gold Nanoparticles

    Science.gov (United States)

    Yamada, Shigeru; Fujita, Satoshi; Uchimura, Eiichiro; Miyake, Masato; Miyake, Jun

    Reverse transfection from a solid surface has the potential to deliver genes into various types of cell and tissue more effectively than conventional methods of transfection. We present a method for reverse transfection using a gold colloid (GC) as a nanoscaffold by generating nanoclusters of the DNA/reagentcomplex on a glass surface, which could then be used for the regulation of the particle size of the complex and delivery of DNA into nuclei. With this method, we have found that the conjugation of gold nanoparticles (20 nm in particle size) to the pEGFP-N1/Jet-PEI complex resulted in an increase in the intensity of fluorescence of enhanced green fluorescent protein (EGFP) (based on the efficiency of transfection) from human mesenchymal stem cells (hMSCs), as compared with the control without GC. In this manner, we constructed a method for reverse transfection using GC to deliver genes into the cells effectively.

  13. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    Purpose – The purpose of this paper is to explore the impact of the product residual value (PRV) and the loss of value over time of returned products in the reverse supply chain configuration. It also examines whether or not the distinction of Fisher's functional and innovative products holds...... that allows for recapturing most of the PRV. These notions have then been tested by analyzing two reverse supply chains with a case study research methodology. Findings – The findings show that low PRV is associated with second-class recovery options (recycling and energy recovery) and that high PRV...... is associated with first-class recovery options (reconditioning and remarketing). When the recovery option is recycling, time is not relevant, the primary objective is cost reduction (efficiency), the chain is centralized, and actors and phases of the reverse chain are determined by the specificity...

  14. Agricultural extension and mass media.

    Science.gov (United States)

    Perraton, H

    1983-12-01

    To learn more about the use of the mass media for agricultural extension, the World Bank has considered the efforts of 2 units: INADES-formation in West Africa and the Extension Aids Branch of Malawi. The INADES-formation study focuses on Cameroon but also considers work in Rwanda and the Ivory Coast. Some general conclusions emerge from a comparison of the 2 organizations. Malawi operates an extension service which reaches farmers through extension agents, through farmer training centers, and through mass media. The Extension Aids Branch (EAB) has responsibility for its media work and broadcasts 4 1/2 hours of radio each week. Its 6 regular radio programs include a general program which interviews farmers, a music request program in which the music is interspersed with farming advice, a farming family serial, and a daily broadcast of agricultural news and information. The 17 cinema vans show some agricultural films, made by EAB, some entertainment films, and some government information films from departments other than the ministry of agriculture. EAB also has a well-developed program of research and evaluation of its own work. INADES-formation, the training section of INADES, works towards social and economic development of the population. It teaches peasant farmers and extension agents and does this through running face-to-face seminars, by publishing a magazine, "Agripromo," and through correspondence courses. In 1978-79 INADES-formation enrolled some 4500 farmers and extension agents as students. Both of these organizations work to teach farmers better agriculture techniques, and both were created in response to the fact that agricultural extension agents cannot meet all the farmers in their area. Despite the similarity of objective, there are differences in methods and philosophy. The EAB works in a single country and uses a variety of mass media, with print playing a minor role. INADES-formation is an international and nongovernmental organization and its

  15. RISKS AND CONTRADICTORY OF INTERNATIONAL CAPITAL FLOWS IN BANKING

    Directory of Open Access Journals (Sweden)

    V. Shevchenko

    2014-03-01

    Full Text Available The content of the international capital flows are studied, its contradictor influence on global and national processes. Some theoretical approaches on contradictory impact of capital flows. The major risks of international capital flows in banking sector are determined including financial, currency, assets value decrease, credit rating etc. The capital flows reversal flows are explained. The modern changes of international capital flows to banking sector of Ukraine are discovered.

  16. Reverse genetics with animal viruses. NSV reverse genetics

    International Nuclear Information System (INIS)

    Mebatsion, T.

    2005-01-01

    New strategies to genetically manipulate the genomes of several important animal pathogens have been established in recent years. This article focuses on the reverse genetics techniques, which enables genetic manipulation of the genomes of non-segmented negative-sense RNA viruses. Recovery of a negative-sense RNA virus entirely from cDNA was first achieved for rabies virus in 1994. Since then, reverse genetic systems have been established for several pathogens of medical and veterinary importance. Based on the reverse genetics technique, it is now possible to design safe and more effective live attenuated vaccines against important viral agents. In addition, genetically tagged recombinant viruses can be designed to facilitate serological differentiation of vaccinated animals from infected animals. The approach of delivering protective immunogens of different pathogens using a single vector was made possible with the introduction of the reverse genetics system, and these novel broad-spectrum vaccine vectors have potential applications in improving animal health in developing countries. (author)

  17. Marburg Virus Reverse Genetics Systems

    Directory of Open Access Journals (Sweden)

    Kristina Maria Schmidt

    2016-06-01

    Full Text Available The highly pathogenic Marburg virus (MARV is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  18. Reverse Zymography: Overview and Pitfalls.

    Science.gov (United States)

    Sharma, Kanika; Bhattacharyya, Debasish

    2017-01-01

    Reverse zymography is a technique by which protease inhibitor(s) in a sample could be electrophoretically separated in a substrate-impregnated acrylamide gel and their relative abundance could be semi-quantified. The gel after electrophoresis is incubated with a protease when the impregnated substrate and all other proteins of the sample are degraded into small peptides except the inhibitor(s) that show clear bands against a white background. Since reverse zymography cannot distinguish between a protease inhibitor and a protein that is resistant against proteolysis, the results should be confirmed from inhibition of protease activity by solution state assay.

  19. Reverse hybrid total hip arthroplasty

    DEFF Research Database (Denmark)

    Wangen, Helge; Havelin, Leif I.; Fenstad, Anne M

    2017-01-01

    Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty....... Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk...

  20. Reference counting for reversible languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2014-01-01

    inverses: Freeing a block of memory is done by running the allocation procedure backwards. Axelsen and Glück use this heap manager to sketch implementation of a simple reversible functional language where pattern matching a constructor is the inverse of construction, so pattern-matching implies......Modern programming languages and operating systems use heap memory that allows allocation and deallocation of memory to be decoupled, so they don't follow a stack discipline. Axelsen and Glück have presented a reversible heap manager where allocation and deallocation are each other's logical...

  1. Nanostructured Electrocatalysts for All-Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Park, Minjoon; Ryu, Jaechan; Cho, Jaephil

    2015-10-01

    Vanadium redox reactions have been considered as a key factor affecting the energy efficiency of the all-vanadium redox flow batteries (VRFBs). This redox reaction determines the reaction kinetics of whole cells. However, poor kinetic reversibility and catalytic activity towards the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples on the commonly used carbon substrate limit broader applications of VRFBs. Consequently, modified carbon substrates have been extensively investigated to improve vanadium redox reactions. In this Focus Review, recent progress on metal- and carbon-based nanomaterials as an electrocatalyst for VRFBs is discussed in detail, without the intention to provide a comprehensive review on the whole components of the system. Instead, the focus is mainly placed on the redox chemistry of vanadium ions at a surface of various metals, different dimensional carbons, nitrogen-doped carbon nanostructures, and metal-carbon composites. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. RURAL EXTENSION EPISTEMOLOGY AND THE TIME OF TOTAL EXTENSION

    Directory of Open Access Journals (Sweden)

    Silvio Calgaro Neto

    2016-09-01

    Full Text Available This article is dedicated to explore the field of knowledge related to rural extension. In general, a three complementary perspective is used as theoretical strategy to present this epistemological study. The first perspective, seeks to accomplish a brief archeology of rural extension, identifying the remarkable historical passages. At the second, we look to some theoretical models through the modern epistemological platform. Finally, the third perspective, aims to present a methodological proposal that contemplate this epistemic characteristics, relating with the contemporary transformations observed in the knowledge construction and technological transference for a rural development. Keywords: Total institutions. University.

  3. Integrating reverse logistics and eco-design: a proposal for a new framework

    Directory of Open Access Journals (Sweden)

    Felipe Kich Gontijo

    2014-07-01

    Full Text Available The concepts of Reverse Logistics and Eco-design are discussed in this paper, suggesting that these applications are often treated differently, thus not being able to achieve a higher performance in relation to environmental sustainability. The reason is most reverse logistics applications have a repairer action, since their waste generation is not planned along with product design. The proposal shows how the two concepts can work together, describing the time of each application.Unfolding the two concepts into reverse channels concerning logistics and life cycle analysis of the product as per eco-design, an application model has been developed, promoting integration between the two practices, so that the reverse supply chain is planned along with the product.The result is the development of a model for implementing reverse logistics integrating eco-design, thus optimizing the reverse flow of waste.

  4. Dynamics of Lithospheric Extension and Residual Topography in Southern Tibet

    Science.gov (United States)

    Chen, B.; Shahnas, M. H.; Pysklywec, R.; Sengul Uluocak, E.

    2017-12-01

    Although the north-south (N-S) convergence between India and Eurasia is ongoing, a number of north-south trending rifts (e.g., Tangra Yum Co Rift, Yadong-Gulu Rift and Cona Rift) and normal faulting are observed at the surface of southern Tibet, suggesting an east-west (E-W) extension tectonic regime. The earthquake focal mechanisms also show that deformation of southern Tibet is dominated by E-W extension across these N-S trending rifts. Because the structure of the lithosphere and underlying mantle is poorly understood, the origin of the east-west extension of southern Tibet is still under debate. Gravitational collapse, oblique convergence, and mantle upwelling are among possible responsible mechanisms. We employ a 3D-spherical control volume model of the present-day mantle flow to understand the relationship between topographic features (e.g., rifts and the west-east extension), intermediate-depth earthquakes, and tectonic stresses induced by mantle flow beneath the region. The thermal structure of the mantle and crust is obtained from P and S-wave seismic inversions and heat flow data. Power-law creep with viscous-plastic rheology, describing the behavior of the lithosphere and mantle material is employed. We determine the models which can best reconcile the observed features of southern Tibet including surface heat flow, residual topography with uplift and subsidence, reported GPS rates of the vertical movements, and the earthquake events. The 3D geodynamic modeling of the contemporary mantle flow-lithospheric response quantifies the relative importance of the various proposed mechanism responsible for the E-W extension and deep earthquakes in southern Tibet. The results also have further implications for the magmatic activities and crustal rheology of the region.

  5. Theory, methods and tools for determining environmental flows for riparian vegetation: Riparian vegetation-flow response guilds

    Science.gov (United States)

    Merritt, D.M.; Scott, M.L.; Leroy, Poff N.; Auble, G.T.; Lytle, D.A.

    2010-01-01

    Riparian vegetation composition, structure and abundance are governed to a large degree by river flow regime and flow-mediated fluvial processes. Streamflow regime exerts selective pressures on riparian vegetation, resulting in adaptations (trait syndromes) to specific flow attributes. Widespread modification of flow regimes by humans has resulted in extensive alteration of riparian vegetation communities. Some of the negative effects of altered flow regimes on vegetation may be reversed by restoring components of the natural flow regime. 2. Models have been developed that quantitatively relate components of the flow regime to attributes of riparian vegetation at the individual, population and community levels. Predictive models range from simple statistical relationships, to more complex stochastic matrix population models and dynamic simulation models. Of the dozens of predictive models reviewed here, most treat one or a few species, have many simplifying assumptions such as stable channel form, and do not specify the time-scale of response. In many cases, these models are very effective in developing alternative streamflow management plans for specific river reaches or segments but are not directly transferable to other rivers or other regions. 3. A primary goal in riparian ecology is to develop general frameworks for prediction of vegetation response to changing environmental conditions. The development of riparian vegetation-flow response guilds offers a framework for transferring information from rivers where flow standards have been developed to maintain desirable vegetation attributes, to rivers with little or no existing information. 4. We propose to organise riparian plants into non-phylogenetic groupings of species with shared traits that are related to components of hydrologic regime: life history, reproductive strategy, morphology, adaptations to fluvial disturbance and adaptations to water availability. Plants from any river or region may be grouped

  6. Convection flow study within a horizontal fluid layer under the action of gas flow

    Directory of Open Access Journals (Sweden)

    Kreta Aleksei

    2016-01-01

    Full Text Available Experimental investigation of convective processes within horizontal evaporating liquid layer under shear–stress of gas flow is presented. It is found the structures of the convection, which move in opposite direction relative to each other. First convective structure moves in reverse direction with the flow of gas, and the second convective structure moves towards the gas flow. Convection flow within the liquid layer is registered with help of PIV technique. Average evaporation flow rate of Ethanol liquid layer under Air gas flow is measured. Influence of the gas velocity, at a constant temperature of 20 °C, on the evaporation flow rate has been studied.

  7. verbal extensions: valency decreasing extensions in the basà ...

    African Journals Online (AJOL)

    Finance

    London: Hodder. Education. Imoh, P.M., 2013. Verbal extensions: Valency increasing operations in Basà verbal system. Paper presented at the West African Languages Congress (WALC) and 26th Annual. Conference of the Linguistic Association of Nigeria (26th CLAN), 29th July to 2nd August. 2013, University of Ibadan, ...

  8. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  9. Time reversal and parity tests

    International Nuclear Information System (INIS)

    Terwilliger, K.

    1975-01-01

    A recent review by Henley discusses the present status of Time Reversal and Parity symmetry violations, and comments on the implications for high energy hadron scattering. This note will briefly summarize the situation with particular attention to the sizes of possible effects, relating them to experimental accuracy available or reasonably possible at the ZGS

  10. A Framework for Reverse Logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2003-01-01

    textabstractReverse Logistics has been stretching out worldwide, involving all the layers of supply chains in various industry sectors. While some actors in the chain have been forced to take products back, others have pro-actively done so, attracted by the value in used products One way or the

  11. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  12. Elementary chaotic snap flows

    International Nuclear Information System (INIS)

    Munmuangsaen, Buncha; Srisuchinwong, Banlue

    2011-01-01

    Highlights: → Five new elementary chaotic snap flows and a generalization of an existing chaotic snap flow have been presented. → Three of all are conservative systems whilst three others are dissipative systems. → Four cases need only a single control parameter and a single nonlinearity. → A cubic case in a jerk representation requires only two terms and a single nonlinearity. - Abstract: Hyperjerk systems with 4th-order derivative of the form x .... =f(x ... ,x .. ,x . ,x) have been referred to as snap systems. Five new elementary chaotic snap flows and a generalization of an existing flow are presented through an extensive numerical search. Four of these flows demonstrate elegant simplicity of a single control parameter based on a single nonlinearity of a quadratic, a piecewise-linear or an exponential type. Two others demonstrate elegant simplicity of all unity-in-magnitude parameters based on either a single cubic nonlinearity or three cubic nonlinearities. The chaotic snap flow with a single cubic nonlinearity requires only two terms and can be transformed to its equivalent dynamical form of only five terms which have a single nonlinearity. An advantage is that such a chaotic flow offers only five terms even though the (four) dimension is high. Three of the chaotic snap flows are characterized as conservative systems whilst three others are dissipative systems. Basic dynamical properties are described.

  13. Is boundary extension emotionally selective?

    Science.gov (United States)

    Ménétrier, Emmanuelle; Didierjean, André; Vieillard, Sandrine

    2013-01-01

    When they have to memorize a picture, people usually build a memory trace including more extensive boundaries than the original picture, a phenomenon known as boundary extension or BE. This article looks at whether the emotion category expressed (i.e., happiness, pleasure, irritation, or anger) by actors in short films could have an influence on the BE effect. The results showed that positively valenced emotions (happiness, pleasure) led to an extension effect, while the negatively valenced ones (anger, irritation) did not produce any significant memory distortion. The arousal dimension of emotions had no significant effect on BE. The current results were discussed in the light of previous studies on the links between BE and emotions.

  14. NDE and plant life extension

    International Nuclear Information System (INIS)

    Liu, S.N.; Ammirato, F.V.; Nottingham, L.D.

    1991-01-01

    Component life extension is the process of making run-repair-replace decisions for plant components and includes a thorough analysis of the capability of the component to perform throughout the projected lifetime. For many critical plant components, nondestructive evaluation (NDE) is essential in determining whether the component can be operated safely and economically in the extended life period and to help utilities determine safe and economic inspection intervals. NDE technology is required for not only detecting defects that could grow to a size of concern during extended lifetimes, but also will be called upon to measure and monitor accumulating material degradation that strongly affects component reliability. This paper discusses the role of NDE in life extension by reviewing three examples--a reactor pressure vessel, steam turbine-generator rotors, and generator retaining rings. In each example, the contribution of NDE to life extension decisions is described. (author)

  15. Elbow arthroscopy: valgus extension overload.

    Science.gov (United States)

    Ahmad, Christopher S; Conway, John E

    2011-01-01

    Valgus torque combined with deceleration produces high compression and shear forces acting on the posteromedial olecranon and the posteromedial trochlea. This valgus extension overload process may cause posteromedial trochlea chondromalacia, chondral flap formation, osteochondrosis, subchondral erosion, a subchondral insufficiency fracture, and marginal exostosis formation. Olecranon pathologies include proximal stress reaction, a posteromedial tip stress fracture, a transverse proximal process stress fracture, exostosis formation, exostosis fragmentation, and intra-articular loose bodies. Symptoms include posteromedial elbow pain during the deceleration phase of the throwing motion. The extension impingement test reproduces posterior or posteromedial pain similar to that experienced while throwing. Special radiographic techniques and CT scans can show loose bodies and osteophyte fragmentation. Surgical treatment is indicated when symptoms persist despite nonsurgical management. Based on clinical and basic science research, all patients with valgus extension overload should be comprehensively evaluated for medial ulnar collateral ligament insufficiency. Surgical treatment is limited to the resection of osteophytes only; normal olecranon should not be resected.

  16. On extensions of superconformal algebras

    International Nuclear Information System (INIS)

    Nagi, Jasbir

    2005-01-01

    Starting from vector fields that preserve a differential form on a Riemann sphere with Grassmann variables, one can construct a superconformal algebra by considering central extensions of the algebra of vector fields. In this paper, the N=4 case is analyzed closely, where the presence of weight zero operators in the field theory forces the introduction of noncentral extensions. How this modifies the existing field theory, representation theory, and Gelfand-Fuchs constructions is discussed. It is also discussed how graded Riemann sphere geometry can be used to give a geometrical description of the central charge in the N=1 theory

  17. Reverse amblyopia with atropine treatment.

    Science.gov (United States)

    Hainline, Bryan C; Sprunger, Derek C; Plager, David A; Neely, Daniel E; Guess, Matthew G

    2009-01-01

    Occlusion, pharmacologic pernalization and combined therapy have been documented in controlled studies to effectively treat amblyopia with few complications. However, there remain concerns about the effectiveness and complications when, as in this case, there are not standardized treatment protocols. A retrospective chart review of 133 consecutive patients in one community based ophthalmology practice treated for amblyopia was performed. Treatments evaluated were occlusion only, atropine penalization, and combination of occlusion and atropine. Reverse amblyopia was defined as having occured when the visual acuity of the sound eye was 3 LogMar units worse than visual acuity of the amblyopia eye after treatment. Improvement in vision after 6 months and 1 year of amblyopia therapy was similar among all three groups: 0.26 LogMar lines and 0.30 in the atropine group, 0.32 and 0.34 in the occlusion group, and 0.24 and 0.32 in the combined group. Eight (6%) patients demonstrated reverse amblyopia. The mean age of those who developed reverse amblyopia was 3.5 years, 1.5 years younger than the mean age of the study population, 7/8 had strabismic amblyopia, 6/8 were on daily atropine and had a mean refractive error of +4.77 diopters in the amblyopic eye and +5.06 diopters in the sound eye. Reverse amblyopia did not occur with occlusion only therapy. In this community based ophthalmology practice, atropine, patching, and combination therapy appear to be equally effective modalities to treat ambyopia. Highly hyperopic patients under 4 years of age with dense, strabismic amblyopia and on daily atropine appeared to be most at risk for development of reverse amblyopia.

  18. Protein synthesis inhibitors attenuate water flow in vasopressin-stimulated toad urinary bladder

    International Nuclear Information System (INIS)

    Hoch, B.S.; Ast, M.B.; Fusco, M.J.; Jacoby, M.; Levine, S.D.

    1988-01-01

    Vasopressin stimulates the introduction of aggregated particles, which may represent pathways for water flow, into the luminal membrane of toad urinary bladder. It is not known whether water transport pathways are degraded on removal from membrane or whether they are recycled. The authors examined the effect of the protein synthesis inhibitors cycloheximide and puromycin using repeated 30-min cycles of vasopressin followed by washout of vasopressin, all in the presence of an osmotic gradient, a protocol that maximizes aggregate turnover. High dose cycloheximide inhibited flow immediately. Low dose cycloheximide did not affect initial flow. In the absence of vasopressin, inhibition did not develop. Despite the inhibition of flow in vasopressin-treated tissues, the cAMP-dependent protein kinase ratio was elevated in cycloheximide-treated tissues, suggesting modulation at a distal site in the stimulatory cascade. [ 14 C]urea permeability was not inhibited by cycloheximide. Puromycin also inhibited water flow by the fourth challenge with vasopressin. The data suggest that protein synthesis inhibitors attenuate flow at a site that is distal to cAMP-dependent protein kinase. However, the reversal of inhibition in MIX-treated tissues suggests that the water pathway can be fully manifested given suitable stimulation. They conclude that either large stores of the transport system are available or that the transport system is extensively recycled on retrieval from the membrane

  19. African Journal of Livestock Extension

    African Journals Online (AJOL)

    African Journal of Livestock Extension aims to bring to the fore the role and significance of livestock in maintaining rural, peri-urban and urban households, vis-à-vis its impact on poverty alleviation, household nutritional status, economic coping strategy and provision of employment. The focus of the journal relates to all ...

  20. Extensiveness of Farmers' Buying Process

    NARCIS (Netherlands)

    Kool, M.; Meulenberg, M.T.G.; Broens, D.F.

    1997-01-01

    In this article we study farmers' buying processes, in particular the selection of a supplier for a given farm input. Extensiveness of farmers' buying processes is defined as the degree information acquisition and alternative evaluation effort carried out to prepare that selection. Hypotheses,

  1. Cross System Extensions (CSE) experience

    International Nuclear Information System (INIS)

    Johnston, T.Y.

    1990-08-01

    Cross System Extension (CSE) provides VM/XA systems with the ability to share minidisks and spool in loosely coupled environment. CSE will also cooperate with the VM/HPO Inter System Facility (ISF) in sharing minidisks between VM/XA and VM/HPO to XA, reliability of CSE, and some operational considerations when running with it

  2. Extension Resources for International Trade

    Science.gov (United States)

    Seal, Susan D.

    2016-01-01

    With the opening of additional trade partnerships, the reduction of global transportation and communication costs, and the increase in demand for U.S. agricultural products and services, international trade is an area of great importance to more and more Extension clients and stakeholders. This article provides information about the primary…

  3. Agricultural Extension. A Reference Manual.

    Science.gov (United States)

    Maunder, Addison, H.

    The basic philosophy of agricultural extension was established in the more highly developed countries over the past century. Newly formed nations, the rural population of which formerly maintained a subsistence agriculture with limited industry, found it essential to establish a better-balanced economy. This led to a variety of rural services and…

  4. Extensions of the standard model

    International Nuclear Information System (INIS)

    Ramond, P.

    1983-01-01

    In these lectures we focus on several issues that arise in theoretical extensions of the standard model. First we describe the kinds of fermions that can be added to the standard model without affecting known phenomenology. We focus in particular on three types: the vector-like completion of the existing fermions as would be predicted by a Kaluza-Klein type theory, which we find cannot be realistically achieved without some chiral symmetry; fermions which are vector-like by themselves, such as do appear in supersymmetric extensions, and finally anomaly-free chiral sets of fermions. We note that a chiral symmetry, such as the Peccei-Quinn symmetry can be used to produce a vector-like theory which, at scales less than M/sub W/, appears to be chiral. Next, we turn to the analysis of the second hierarchy problem which arises in Grand Unified extensions of the standard model, and plays a crucial role in proton decay of supersymmetric extensions. We review the known mechanisms for avoiding this problem and present a new one which seems to lead to the (family) triplication of the gauge group. Finally, this being a summer school, we present a list of homework problems. 44 references

  5. An extension of Babinet's principle

    International Nuclear Information System (INIS)

    da Silveira, R.

    1990-07-01

    It is shown that the diffraction pattern produced by any of two complementary screens and the one produced by a slit having the shape of their boundary, oscillates in opposite phase. This extension of Babinet's principle is illustrated with examples from nuclear scattering and classical optics

  6. Extension properties of states on operator algebras

    Science.gov (United States)

    Hamhalter, Jan

    1995-08-01

    We summarize and deepen some recent results concerning the extension problem for states on operator algebras and general quantum logics. In particular, we establish equivalence between the Gleason extension property, the Hahn-Banach extension property, and the universal state extension property of projection logics. Extensions of Jauch-Piron states are investigated.

  7. Reversal agents in anaesthesia and critical care

    Directory of Open Access Journals (Sweden)

    Nibedita Pani

    2015-01-01

    Full Text Available Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice.

  8. Trend towards reverse leach process

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The South African gold mining industry is making notable strides in improving recovery methods for both gold and uranium with significant additions to profits because of higher efficiencies and reductions in costs in the recovery processes. The most notable step on the gold side recently is the adoption of the reverse leach process at Buffelsfontein and Western Deep Levels. This process was pioneered at Hartebeesfontein as far back as 1975 and when introduced there resulted in a two and a half per cent improvement in recovery efficiencies. The essence of reverse leaching under which the uranium is recovered before the gold is the fact that the gold partly coated with iron oxide or locked in uranite, is exposed to be recovered later by cyanidation

  9. Reversible evolution of charged ergoregions

    Energy Technology Data Exchange (ETDEWEB)

    Kokkotas, K.; Spyrou, N.

    1987-07-01

    The reversible evolution of a charged rotating ergoregion, due to the injection into it of particles with mass-energy and angular momentum, is studied systematically. As in the uncharged case, a bulge always forms on the outer boundary of the ergoregion due to the latter's angular momentum. The behavior of the bulge's position, relative to the black hole's rotation axis and equatorial plane, is studied, on the basis of the cosmic censorship hypothesis, during the ergoregion's reversible evolution. The range of the permitted values of the ergoregion's linear dimensions along the rotation axis and perpendicular to it is specified. Finally the differences with the evolution of an uncharged ergoregion are pointed out and discussed.

  10. Malware analysis and reverse engineering

    OpenAIRE

    Šváb, Martin

    2014-01-01

    Focus of this thesis is reverse engineering in information technology closely linked with the malware analysis. It explains fundamentals of IA-32 processors architecture and basics of operating system Microsoft Windows. Main part of this thesis is dedicated to the malware analysis, including description of creating a tool for simplification of static part of the analysis. In Conclusion various approaches to the malware analysis, which were described in previous part of the thesis, are practic...

  11. How to play Reverse Hex

    DEFF Research Database (Denmark)

    Toft, Bjarne; Hayward, Ryan B.; Henderson, Philip

    2012-01-01

    We present new results on how to play Reverse Hex, also known as Rex, or Misère Hex, on n × n boards. We give new proofs – and strengthened versions – of Lagarias and Sleator’s theorem (for n × n boards, each player can prolong the game until the board is full, so the first/second player can alwa...

  12. Theory of field reversed configurations

    International Nuclear Information System (INIS)

    Steinhauer, L.C.

    1990-01-01

    This final report surveys the results of work conducted on the theory of field reversed configurations. This project has spanned ten years, beginning in early 1980. During this period, Spectra Technology was one of the leading contributors to the advances in understanding FRC. The report is organized into technical topic areas, FRC formation, equilibrium, stability, and transport. Included as an appendix are papers published in archival journals that were generated in the course of this report. 33 refs

  13. Reverse engineering of integrated circuits

    Science.gov (United States)

    Chisholm, Gregory H.; Eckmann, Steven T.; Lain, Christopher M.; Veroff, Robert L.

    2003-01-01

    Software and a method therein to analyze circuits. The software comprises several tools, each of which perform particular functions in the Reverse Engineering process. The analyst, through a standard interface, directs each tool to the portion of the task to which it is most well suited, rendering previously intractable problems solvable. The tools are generally used iteratively to produce a successively more abstract picture of a circuit, about which incomplete a priori knowledge exists.

  14. Risperidone-induced reversible neutropenia.

    Science.gov (United States)

    Kattalai Kailasam, Vasanth; Chima, Victoria; Nnamdi, Uchechukwu; Sharma, Kavita; Shah, Kairav

    2017-01-01

    This case report presents a 44-year-old man with a history of schizophrenia who developed neutropenia on risperidone therapy. The patient's laboratory reports showed a gradual decline of leukocytes and neutrophils after resolution and rechallenging. This was reversed with the discontinuation of risperidone and by switching to olanzapine. In this case report, we also discuss the updated evidence base for management of risperidone-induced neutropenia.

  15. NERVE: New Enhanced Reverse Vaccinology Environment

    Directory of Open Access Journals (Sweden)

    Filippini Francesco

    2006-07-01

    Full Text Available Abstract Background Since a milestone work on Neisseria meningitidis B, Reverse Vaccinology has strongly enhanced the identification of vaccine candidates by replacing several experimental tasks using in silico prediction steps. These steps have allowed scientists to face the selection of antigens from the predicted proteome of pathogens, for which cell culture is difficult or impossible, saving time and money. However, this good example of bioinformatics-driven immunology can be further developed by improving in silico steps and implementing biologist-friendly tools. Results We introduce NERVE (New Enhanced Reverse Vaccinology Environment, an user-friendly software environment for the in silico identification of the best vaccine candidates from whole proteomes of bacterial pathogens. The software integrates multiple robust and well-known algorithms for protein analysis and comparison. Vaccine candidates are ranked and presented in a html table showing relevant information and links to corresponding primary data. Information concerning all proteins of the analyzed proteome is not deleted along selection steps but rather flows into an SQL database for further mining and analyses. Conclusion After learning from recent years' works in this field and analysing a large dataset, NERVE has been implemented and tuned as the first available tool able to rank a restricted pool (~8–9% of the whole proteome of vaccine candidates and to show high recall (~75–80% of known protective antigens. These vaccine candidates are required to be "safe" (taking into account autoimmunity risk and "easy" for further experimental, high-throughput screening (avoiding possibly not soluble antigens. NERVE is expected to help save time and money in vaccine design and is available as an additional file with this manuscript; updated versions will be available at http://www.bio.unipd.it/molbinfo.

  16. Experimental Studies of Flow Separation of the NACA 2412 Airfoil at Low Speeds

    Science.gov (United States)

    Seetharam, H. C.; Rodgers, E. J.; Wentz, W. H., Jr.

    1997-01-01

    Wind tunnel tests have been conducted on an NACA 2412 airfoil section at Reynolds number of 2.2 x 10(exp 6) and Mach number of 0.13. Detailed measurements of flow fields associated with turbulent boundary layers have been obtained at angles of attack of 12.4 degrees, 14.4 degrees, and 16.4 degrees. Pre- and post-separated velocity and pressure survey results over the airfoil and in the associated wake are presented. Extensive force, pressure, tuft survey, hot-film survey, local skin friction, and boundary layer data are also included. Pressure distributions and separation point locations show good agreement with theory for the two layer angles of attack. Boundary layer displacement thickness, momentum thickness, and shape factor agree well with theory up to the point of separation. There is considerable disparity between extent of flow reversal in the wake as measured by pressure and hot-film probes. The difference is attributed to the intermittent nature of the flow reversal.

  17. An extension of Pohlmeyer's theorem

    International Nuclear Information System (INIS)

    Rosten, Oliver J

    2010-01-01

    Applying the exact renormalization group to scalar field theory in Euclidean space of general (not necessarily integer) dimension, it is proven that the only fixed point with vanishing anomalous dimension is the Gaussian one. The proof requires positivity of the two-point connected correlation function together with a technical assumption concerning solutions of the flow equation. The method, in which the representation of the flow equation as a heat equation plays a central role, extends directly to non-gauge theories with arbitrary matter content (though nonlinear sigma models are beyond the scope of the current method).

  18. Blood Cell Interactions and Segregation in Flow

    OpenAIRE

    Munn, Lance L.; Dupin, Michael M.

    2008-01-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allo...

  19. Curve collection, extension of databases

    International Nuclear Information System (INIS)

    Gillemot, F.

    1992-01-01

    Full text: Databases: generally calculated data only. The original measurements: diagrams. Information loss between them Expensive research eg. irradiation, aging, creep etc. Original curves should be stored for reanalysing. The format of the stored curves: a. Data in ASCII files, only numbers b. Other information in strings in a second file Same name, but different extension. Extensions shows the type of the test and the type of the file. EXAMPLES. TEN is tensile information, TED is tensile data, CHN is Charpy informations, CHD is Charpy data. Storing techniques: digitalised measurements, digitalising old curves stored on paper. Use: making catalogues, reanalysing, comparison with new data. Tools: mathematical software packages like quattro, genplot, exel, mathcad, qbasic, pascal, fortran, mathlab, grapher etc. (author)

  20. Extension agents and conflict narratives

    DEFF Research Database (Denmark)

    Bond, Jennifer Lauren

    2016-01-01

    Purpose: This work investigated the narratives of development extensionists in relation to natural resource conflict, in order to understand the competing discourses surrounding the wicked problems of natural resource management in Laikipia County, Kenya. Methodology: Q methodology was used...... to elicit the conflict narratives present among extension professionals. A concourse of 221 statements were devised from interviews and group discussions with key informants and a final sample of 49 statements was used for the sorting. Thirteen Q-sorts were undertaken with among rural extension...... professionals from government, non-government, faith-based and private organizations. Findings: Four factors were elicited from the data, labelled—A: ‘Improved Leadership’; B: ‘Resource-centred conflict’; C: ‘Improved Governance’; and D: ‘Improved Management’. Practical Implications: Narratives of neo...