WorldWideScience

Sample records for local buoyancy effects

  1. Effects of Buoyancy on Laminar and Turbulent Premixed V-Flame

    Science.gov (United States)

    Cheng, Robert K.; Bedat, Benoit

    1997-01-01

    Turbulent combustion occurs naturally in almost all combustion systems and involves complex dynamic coupling of chemical and fluid mechanical processes. It is considered as one of the most challenging combustion research problems today. Though buoyancy has little effect on power generating systems operating under high pressures (e.g., IC engines and turbines), flames in atmospheric burners and the operation of small to medium furnaces and boilers are profoundly affected by buoyancy. Changes in burner orientation impacts on their blow-off, flash-back and extinction limits, and their range of operation, burning rate, heat transfer, and emissions. Theoretically, buoyancy is often neglected in turbulent combustion models. Yet the modeling results are routinely compared with experiments of open laboratory flames that are obviously affected by buoyancy. This inconsistency is an obstacle to reconciling experiments and theories. Consequently, a fundamental understanding of the coupling between turbulent flames and buoyancy is significant to both turbulent combustion science and applications. The overall effect of buoyancy relates to the dynamic interaction between the flame and its surrounding, i.e., the so-called elliptical problem. The overall flame shape, its flowfield, stability, and mean and local burning rates are dictated by both upstream and downstream boundary conditions. In steady propagating premixed flames, buoyancy affects the products region downstream of the flame zone. These effects are manifested upstream through the mean and fluctuating pressure fields to influence flame stretch and flame wrinkling. Intuitively, the effects buoyancy should diminish with increasing flow momentum. This is the justification for excluding buoyancy in turbulent combustion models that treats high Reynolds number flows. The objectives of our experimental research program is to elucidate flame-buoyancy coupling processes in laminar and turbulent premixed flames, and to

  2. Buoyancy Effects in Turbulent Jet Flames in Crossflow

    Science.gov (United States)

    Boxx, Isaac; Idicheria, Cherian; Clemens, Noel

    2003-11-01

    The aim of this study is to investigate the effects of buoyancy on the structure of turbulent, non-premixed hydrocarbon jet-flames in crossflow (JFICF). This was accomplished using a small jet-in-crossflow facility which can be oriented at a variety of angles with respect to the gravity vector. This facility enables us to alter the relative influence of buoyancy on the JFICF without altering the jet-exit Reynolds number, momentum flux ratio or the geometry of the system. Results are compared to similar, but non-buoyant, JFICF studied in microgravity. Departures of jet-centerline trajectory from the well-known power-law scaling of turbulent JFICF were used to explore the transition from a buoyancy-influenced regime to a momentum dominated one. The primary diagnostic was CCD imaging of soot-luminosity. We present results on ethylene jet flames with jet-exit Reynolds numbers of 1770 to 8000 and momentum flux ratios of 5 to 13.

  3. The effects of buoyancy on turbulent nonpremixed jet flames in crossflow

    Science.gov (United States)

    Boxx, Isaac G.

    An experimental research study was conducted to investigate what effect buoyancy had on the mean and instantaneous flow-field characteristics of turbulent jet-flames in crossflow (JFICF). The study used an experimental technique wherein a series of normal-gravity, hydrogen-diluted propane JFICF were compared with otherwise identical ones in low-gravity. Experiments were conducted at the University of Texas Drop Tower Facility, a new microgravity science laboratory built for this study at the University of Texas at Austin. Two different diagnostic techniques were employed, high frame-rate digital cinematographic imaging and planar laser Mie scattering (PLMS). The flame-luminosity imaging revealed significant elongation and distortion of the large-scale luminous structure of the JFICF. This was seen to affect the flametip oscillation and burnout characteristics. Mean and root-mean-square (RMS) images of flame-luminosity were computed from the flame-luminosity image sequences. These were used to compare visible flame-shapes, flame chord-lengths and jet centerline-trajectories of the normal- and low-gravity flames. In all cases the jet-centerline penetration and mean luminous flame-width were seen to increase with decreasing buoyancy. The jet-centerline trajectories for the normal-gravity flames were seen to behave differently to those of the low-gravity flames. This difference led to the conclusion that the jet transitions from a momentum-dominated forced convection limit to a buoyancy-influenced regime when it reaches xiC ≈ 3, where xiC is the Becker and Yamazaki (1978) buoyancy parameter based on local flame chord-length. The mean luminous flame-lengths showed little sensitivity to buoyancy or momentum flux ratio. Consistent with the flame-luminosity imaging experiments, comparison of the instantaneous PLMS flow-visualization images revealed substantial buoyancy-induced elongation and distortion of the large-scale shear-layer vortices in the flow. This effect

  4. The effects of buoyancy on shear-induced melt bands in a compacting porous medium

    Science.gov (United States)

    Butler, S. L.

    2009-03-01

    It has recently been shown [Holtzman, B., Groebner, N., Zimmerman, M., Ginsberg, S., Kohlstedt, D., 2003. Stress-driven melt segregation in partially molten rocks. Geochem. Geophys. Geosyst. 4, Art. No. 8607; Holtzman, B.K., Kohlstedt, D.L., 2007. Stress-driven melt segregation and strain partitioning in partially molten rocks: effects of stress and strain. J. Petrol. 48, 2379-2406] that when partially molten rock is subjected to simple shear, bands of high and low porosity are formed at a particular angle to the direction of instantaneous maximum extension. These have been modeled numerically and it has been speculated that high porosity bands may form an interconnected network with a bulk, effective permeability that is enhanced in a direction parallel to the bands. As a result, the bands may act to focus mantle melt towards the axis of mid-ocean ridges [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679]. In this contribution, we examine the combined effects of buoyancy and matrix shear on a deforming porous layer. The linear theory of Spiegelman [Spiegelman, M., 1993. Flow in deformable porous media. Part 1. Simple analysis. J. Fluid Mech. 247, 17-38; Spiegelman, M., 2003. Linear analysis of melt band formation by simple shear. Geochem. Geophys. Geosyst. 4, doi:10.1029/2002GC000499, Article 8615] and Katz et al. [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679] is generalized to include both the effects of buoyancy and matrix shear on a deformable porous layer with strain-rate dependent rheology. The predictions of linear theory are compared with the early time evolution of our 2D numerical model and they are found to be in excellent agreement. For conditions similar to the upper mantle, buoyancy forces can be similar to or much greater than matrix shear-induced forces. The

  5. Inherent work suit buoyancy distribution: effects on lifejacket self-righting performance.

    Science.gov (United States)

    Barwood, Martin J; Long, Geoffrey M; Lunt, Heather; Tipton, Michael J

    2014-09-01

    Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman's test to the 0.05 alpha level. All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario.

  6. Large eddy simulation of a buoyancy-aided flow in a non-uniform channel – Buoyancy effects on large flow structures

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); He, S., E-mail: s.he@sheffield.ac.uk [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2017-02-15

    Highlights: • Buoyancy may greatly redistribute the flow in a non-uniform channel. • Flow structures in the narrow gap are greatly changed when buoyancy is strong. • Large flow structures exist in wider gap, which is enhanced when heat is strong. • Buoyancy reduces mixing factor caused by large flow structures in narrow gap. - Abstract: It has been a long time since the ‘abnormal’ turbulent intensity distribution and high inter-sub-channel mixing rates were observed in the vicinity of the narrow gaps formed by the fuel rods in nuclear reactors. The extraordinary flow behaviour was first described as periodic flow structures by Hooper and Rehme (1984). Since then, the existences of large flow structures were demonstrated by many researchers in various non-uniform flow channels. It has been proved by many authors that the Strouhal number of the flow structure in the isothermal flow is dependent on the size of the narrow gap, not the Reynolds number once it is sufficiently large. This paper reports a numerical investigation on the effect of buoyancy on the large flow structures. A buoyancy-aided flow in a tightly-packed rod-bundle-like channel is modelled using large eddy simulation (LES) together with the Boussinesq approximation. The behaviour of the large flow structures in the gaps of the flow passage are studied using instantaneous flow fields, spectrum analysis and correlation analysis. It is found that the non-uniform buoyancy force in the cross section of the flow channel may greatly redistribute the velocity field once the overall buoyancy force is sufficiently strong, and consequently modify the large flow structures. The temporal and axial spatial scales of the large flow structures are influenced by buoyancy in a way similar to that turbulence is influenced. These scales reduce when the flow is laminarised, but start increasing in the turbulence regeneration region. The spanwise scale of the flow structures in the narrow gap remains more or

  7. Buoyancy effects in vertical rectangular duct with coplanar magnetic field and single sided heat load

    Science.gov (United States)

    Kostichev, P. I.; Poddubnyi, I. I.; Razuvanov, N. G.

    2017-11-01

    In some DEMO blanket designs liquid metal flows in vertical ducts of rectangular cross-section between ceramic breeder units providing their cooling. Heat exchange in these conditions is governed by the influence of magnetic field (coplanar) and by buoyancy effects that depend on the flow orientation to the gravity vector (downward and upward flow). Magnetohydrodynamic and heat transfer of liquid metal in vertical rectangular ducts is not well researched. Experimental study of buoyancy effects in rectangular duct with coplanar magnetic field for one-sided heat load and downward and upward flowsis presented in this paper. The detail research with has been done on mercury MHD close loop with using of the probe technique allow to discover several advantageous and disadvantageous effects. The intensive impact of buoyancy force has been observed in a few regime of downward flow which has been laminarized by magnetic field. Due to the development in the flow of the secondary large-scale vortices heat transfer improved and the temperature fluctuations of the abnormally high intensity have been fixed. On the contrary, in the upward flow the buoyancy force stabilized the flow which lead to decreasing of the turbulence heat transfer ratio and, consequently, deterioration of heat transfer.

  8. Coupled thermo-capillary and buoyancy convection in a liquid layer locally heated on its free surface

    International Nuclear Information System (INIS)

    Favre, E.

    1997-01-01

    Coupled buoyancy and thermo-capillary convection lead to a convective motion of the interface liquid/gas, which changes drastically the heat and mass transfer across the liquid layer. Two experiments are considered, depending on the fluid: oil or mercury. The liquid is set in a cooled cylindrical vessel, and heated by a heat flux across the center of the free surface. The basic flow, in the case of oil, is a torus. When the heat parameter increases, a stationary flow looking like petals or rays appears when the aspect ratio length/depth is small, and like concentric rings in the case of large values of the aspect ratio. The lateral confinement selects the azimuthal length wave. In the case of petals-like flow, a sub-critical Hopf bifurcation is underlined. The turbulence is found to be 'weak', even for the largest values of the Marangoni number (Ma ≅ 1.3 * 10 5 ). In the case of mercury, the thermo-capillary effect is reduced to zero, due to impurities at the surface, which have special trajectories we describe and compare to a simpler experiment. The only buoyancy forces induces an un-stationary, weakly turbulent flow as soon as the heating power exceeds 4 W (≅ 4.5 * 10 3 , calculated with h = 1 mm). The last part concerns the analysis of the effect on the flow of the boundary conditions, the geometry, the Prandtl number, the buoyancy force, with the help of the literature. Results concerning heat transfer, especially the exponent of the law Nusselt number vs. heating power, are compared with available data. (author) [fr

  9. Thermo capillary and buoyancy convection in a fluid locally heated on its free surface; Convection thermocapillaire et thermogravitaire dans un fluide chauffe localement sur sa surface libre

    Energy Technology Data Exchange (ETDEWEB)

    Favre, E.

    1997-09-26

    coupled buoyancy and thermo-capillary convection lead to a convective motion of the interface liquid/gas which drastically changes the heat and mass transfer across the liquid layer. Two experiments were considered, depending on the fluid: oil or mercury. The liquid is set in a cooled cylindrical vessel, and heated by a heat flux across the center of the free surface. The basic flow, in the case of oil, is a torus. When the heat parameter increases, a stationary flow appears as petals or rays when the aspect ratio. The lateral confinement selects the azimuthal wavelength. In the case of petals-like flow, a sub-critical Hopf bifurcation is underlined. The turbulence is found to be `weak`, even for the largest values of the Marangoni number (Ma = 1.3 10{sup 5}). In the case of mercury, the thermo-capillary effect is reduced to zero to impurities at the surface which have special trajectories we describe and compare to a simpler experiment. Only the buoyancy forces induce a unstationary, weakly turbulent flow as soon as the heating power exceeds 4W (Ra = 4.5 10{sup 3}, calculated with h = 1 mm). The past part concerns the analysis of the effect on the flow of the boundary conditions, the geometry, the Prandtl number and the buoyancy force with the help of the literature. Results concerning heat transfer, in particular the exponent of the law Nusselt number vs. heating power, were compared with available data. (author) 115 refs.

  10. Density-ratio effects on buoyancy-driven variable-density turbulent mixing

    Science.gov (United States)

    Aslangil, Denis; Livescu, Daniel; Banerjee, Arindam

    2017-11-01

    Density-ratio effects on the turbulent mixing of two incompressible, miscible fluids with different densities subject to constant acceleration are studied by means of high-resolution Direct Numerical Simulations. In a triply periodic domain, turbulence is generated by stirring in response to the differential buoyancy forces within the flow. Later, as the fluids become molecularly mixed, dissipation starts to overcome turbulence generation by bouyancy. Thus, the flow evolution includes both turbulence growth and decay, and it displays features present in the core region of the mixing layer of the Rayleigh-Taylor as well as Richtmyer-Meshkov instabilities. We extend the previous studies by investigating a broad range of density-ratio, from 1-14.4:1, corresponding to Atwood numbers of 0.05-0.87. Here, we focus on the Atwood number dependence of mixing-efficiency, that is defined based on the energy-conversion ratios from potential energy to total and turbulent kinetic energies, the decay characteristics of buoyancy-assisted variable-density homogeneous turbulence, and the effects of high density-ratios on the turbulence structure and mixing process. Authors acknowledge financial support from DOE-SSAA (DE-NA0003195) and NSF CAREER (#1453056) awards.

  11. The Effects of Buoyancy on Characteristics of Turbulent Nonpremixed Jet Flames

    Science.gov (United States)

    Idicheria, Cherian; Boxx, Isaac; Clemens, Noel

    2002-11-01

    This work addresses the influence of buoyant forces on the underlying structure of turbulent nonpremixed jet flames. Buoyancy effects are investigated by studying transitional and turbulent propane and ethylene flames (Re_D=2500-10500) at normal, low and microgravity conditions. The reduced gravity experiments are conducted by dropping a combustion rig in the University of Texas 1.25-second drop tower and the NASA Glenn 2.2-second drop tower. The diagnostic employed is high-speed luminosity imaging using a CCD camera. The images obtained are used to compare flame length, mean, RMS and flame tip oscillation characteristics The results showed that, in contrast to previous studies, the high Reynolds number flames at all gravity levels were essentially identical. Furthermore, the parameter ξL (Becker and Yamazaki, 1978) is sufficient for quantifying the effects of buoyancy on the flame characteristics. The large-scale structure and flame tip dynamics are essentially identical to those of purely momentum driven flames provided ξL is less than approximately 3.

  12. The effect of centrifugal buoyancy on the heat transport in rotating Rayleigh-Bénard convection

    Science.gov (United States)

    Horn, Susanne; Aurnou, Jonathan

    2017-11-01

    In a rapidly rotating and differentially heated fluid, the centrifugal acceleration can play a similar role to that of gravity in generating convective motion. However, in the paradigm system of rotating Rayleigh-Bénard convection, centrifugal buoyancy is typically not considered in theoretical studies and, thus, usually undesired in laboratory experiments, despite being unavoidable. How centrifugal buoyancy affects the turbulent flow, including the heat transport, is still largely unknown, in particular, when it can be considered negligible. We study this problem by means of direct numerical simulations. Unlike in experiments, we are able to systematically vary the Froude number Fr (ratio of centrifugal to gravitational acceleration) and the Rossby number Ro (dimensionless rotation rate) independently, and even set each to zero exactly. We show that the centrifugal acceleration simultaneously leads to contending phenomena, e.g. reflected by an increase and a decrease of the center temperature, or a suppression and an enhancement of the heat transfer efficiency. Which one prevails as net effect strongly depends on the combination of Fr and Ro. Furthermore, we discuss implications for experiments of rapidly rotating convection. SH acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG) under Grant HO 5890/1-1, JA by the NSF Geophysics Program.

  13. Buoyancy effects on thermal behavior of a flat-plate solar collector

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon

    2008-01-01

    Theoretical and experimental investigations of the flow and temperature distribution in a 12.53 m(2) solar collector panel with an absorber consisting of two vertical manifolds interconnected by 16 parallel horizontal fins have been carried out. The investigations are focused on overheating...... and the influence of the buoyancy effects are considered in the investigations. Further experimental investigations of the solar collector panel are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the back of the absorber tubes. The measured temperatures....... The CFD calculations elucidate the flow and temperature distribution in the collector panels of different designs. Based on the investigations, recommendations are given in order to avoid overheating or boiling problems in the solar collector panel....

  14. Effect of buoyancy on fuel containment in an open-cycle gas-core nuclear rocket engine.

    Science.gov (United States)

    Putre, H. A.

    1971-01-01

    Analysis aimed at determining the scaling laws for the buoyancy effect on fuel containment in an open-cycle gas-core nuclear rocket engine, so conducted that experimental conditions can be related to engine conditions. The fuel volume fraction in a short coaxial flow cavity is calculated with a programmed numerical solution of the steady Navier-Stokes equations for isothermal, variable density fluid mixing. A dimensionless parameter B, called the Buoyancy number, was found to correlate the fuel volume fraction for large accelerations and various density ratios. This parameter has the value B = 0 for zero acceleration, and B = 350 for typical engine conditions.

  15. Effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Butts, Ian; Munk, Peter

    2016-01-01

    sizes, while the remaining four salt types resulted in smaller eggs. All salt types except NaCl treatments led to high fertilization rates and had no effect on fertilization success as well as egg neutral buoyancies at 7 h post-fertilization. The study points to the importance of considering ionic...... and egg buoyancy. Egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. Activation salinities between 30–40 practical salinity unit (psu) produced higher quality eggs and generally larger egg diameters. Chorion...

  16. Radiative effects on turbulent buoyancy-driven air flow in open square cavities

    International Nuclear Information System (INIS)

    Zamora, B.; Kaiser, A.S.

    2016-01-01

    The effects of the radiative effects and the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low- Reynolds k-ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide range of the Rayleigh number varying from 10 3 to 10 16 . The results obtained taking into account the variable thermophysical properties of air are compared to those calculated assuming constant properties and the Boussinesq approximation. In addition, the influence of considering surface radiative effects on the differences reached for the Nusselt number and the mass flow rate obtained with several intensities of heating is studied; specifically, the effects of thermal radiation on the appearance of the burnout phenomenon is analyzed. The changes produced in the flow patterns into the cavity when the radiative heat transfer and the effects of variation of properties are relevant, are also shown. (authors)

  17. Buoyancy effects in overcooling transients calculated for the NRC pressurized thermal shock study

    International Nuclear Information System (INIS)

    Theofanous, T.G.; Iyer, K.; Nourbakhsh, H.P.; Gherson, P.

    1986-05-01

    The thermal-hydraulic responses of three PWRs (Oconee, Calvert Cliffs, and H.B. Robinson), to postulated Pressurized Thermal Shock (PTS) scenarios, which were originally determined by RELAP5 and TRAC calculations, are being further developed here with regard to buoyancy/stratification effects. These three PWRs were the subject of the NRC PTS study, and the present results helped define the thermal-hydraulic conditions utilized in the fracture mechanics calculations carried out at ORNL. The computer program REMIX, which is based on the Regional Mixing Model (RMM), was the analytical tool employed, while Purdue's 1/2-Scale HPI Thermal Mixing facility provided the basis for experimental support. Important mixing and wall heat transfer regimes are delineated on the basis of these results. We conclude that stratification is important only in cases of complete loop stagnation and that mixed-convection effects are important for downcomer flow velocities below approx.0.25 m/s. The stratification is small in magnitude, however it is important in creating a recirculating flow pattern which activates the lower plenum, pump and loop seal volumes, to participate in the mixing process. This mixing process together with the heat input from the wall metal significantly impact the cooldown rates. Heat transfer in the plume region is dominated by forced convection. On the other hand, the presence of the Reactor Pressure Vessel (RPV) wall cladding and wall conduction significantly dampen the free convection effects in the low velocity, mixed-convection, regime. For the stagnant loop cases, all locations outside the plume region are included in this regime. In the presence of natural loop circulation and a uniformly distributed downcomer flow, the mixed convection regime is also expected, however, the forced convection regime can also be observed in highly asymmetric flow behavior

  18. Effects of buoyancy and thermal radiation on MHD flow over a stretching porous sheet using homotopy analysis method

    Directory of Open Access Journals (Sweden)

    Yahaya Shagaiya Daniel

    2015-09-01

    Full Text Available This paper investigates the theoretical influence of buoyancy and thermal radiation on MHD flow over a stretching porous sheet. The model which constituted highly nonlinear governing equations is transformed using similarity solution and then solved using homotopy analysis method (HAM. The analysis is carried out up to the 5th order of approximation and the influences of different physical parameters such as Prandtl number, Grashof number, suction/injection parameter, thermal radiation parameter and heat generation/absorption coefficient and also Hartman number on dimensionless velocity, temperature and the rate of heat transfer are investigated and discussed quantitatively with the aid of graphs. Numerical results obtained are compared with the previous results published in the literature and are found to be in good agreement. It was found that when the buoyancy parameter and the fluid velocity increase, the thermal boundary layer decreases. In case of the thermal radiation, increasing the thermal radiation parameter produces significant increases in the thermal conditions of the fluid temperature which cause more fluid in the boundary layer due to buoyancy effect, causing the velocity in the fluid to increase. The hydrodynamic boundary layer and thermal boundary layer thickness increase as a result of increase in radiation.

  19. The effect of buoyancy on flow and heat transfer in curved pipes

    OpenAIRE

    Mochizuki, Munekazu; Ishigaki, Hiroshi; 望月 宗和; 石垣 博

    1994-01-01

    Fully developed laminar flow in a heated horizontal curved pipe is studied numerically. The thermal boundary conditions at the wall are uniform wall heat flux axially and uniform wall temperature peripherally. Flow and heat transfer are governed by Dean number, Prandtl number and buoyancy number. Detailed prediction of the friction factor, average heat transfer rate, velocity profile, temperature profile and secondary-flow streamlines are given.

  20. Neutral Buoyancy Laboratory (NBL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility,...

  1. Buoyancy-driven instability in a vertical cylinder: Binary fluids with Soret effect. I - General theory and stationary stability results

    Science.gov (United States)

    Hardin, G. R.; Sani, R. L.; Henry, D.; Roux, B.

    1990-01-01

    The buoyancy-driven instability of a monocomponent or binary fluid completely contained in a vertical circular cylinder is investigated, including the influence of the Soret effect for the binary mixture. The Boussinesq approximation is used, and the resulting linear stability problem is solved using a Galerkin technique. The analysis considers fluid mixtures ranging from gases to liquid metals. The flow structure is found to depend strongly on both the cylinder aspect ratio and the magnitude of the Soret effect. The predicted stability limits are shown to agree closely with experimental observations.

  2. Center of buoyancy definition

    International Nuclear Information System (INIS)

    Sandberg, V.

    1988-12-01

    The center of buoyancy of an arbitrary shaped body is defined in analogy to the center of gravity. The definitions of the buoyant force and center of buoyancy in terms of integrals over the area of the body are converted to volume integrals and shown to have simple intuitive interpretations

  3. Investigation of buoyancy effects on turbulent nonpremixed jet flames by using normal and low-gravity conditions

    Science.gov (United States)

    Idicheria, Cherian Alex

    An experimental study was performed with the aim of investigating the structure of transitional and turbulent nonpremixed jet flames under different gravity conditions. In particular, the focus was to determine the effect of buoyancy on the mean and fluctuating characteristics of the jet flames. Experiments were conducted under three gravity levels, viz. 1 g, 20 mg and 100 mug. The milligravity and microgravity conditions were achieved by dropping a jet-flame rig in the UT-Austin 1.25-second and the NASA-Glenn Research Center 2.2-second drop towers, respectively. The principal diagnostics employed were time-resolved, cinematographic imaging of the visible soot luminosity and planar laser Mie scattering (PLMS). For the cinematographic flame luminosity imaging experiments, the flames studied were piloted nonpremixed propane, ethylene and methane jet flames at source Reynolds numbers ranging from 2000 to 10500. From the soot luminosity images, mean and root-mean square (RMS) images were computed, and volume rendering of the image sequences was used to investigate the large-scale structure evolution and flame tip dynamics. The relative importance of buoyancy was quantified with the parameter, xL , as defined by Becker and Yamazaki [1978]. The results show, in contrast to previous microgravity studies, that the high Reynolds number flames have the same flame length irrespective of the gravity level. The RMS fluctuations and volume renderings indicate that the large-scale structure and flame tip dynamics are essentially identical to those of purely momentum driven flames provided xL is approximately less than 2. The volume-renderings show that the luminous structure celerities (normalized by jet exit velocity) are approximately constant for xL 8. The celerity values for xL > 8 are seen to follow a x3/2L scaling, which can be predicted with a simplified momentum equation analysis for the buoyancy-dominated regime. The underlying turbulent structure and mean mixture

  4. An analysis of the effect of buoyancy on phase distribution phenomena

    International Nuclear Information System (INIS)

    Maneesh Singhal; Richard T Lahey Jr

    2005-01-01

    Full text of publication follows: It is well known that pronounced lateral phase distributions may occur in two-phase conduit flows. Moreover, the lateral phase distribution appears to strongly influenced by the buoyancy of the dispersed phase. This study used a state-of-the-art two-fluid model, having no arbitrary coefficients, to predict steady, fully developed phase distribution in pipe flows. In particular, bubbly up-flows and down-flows in pipes, and slurry up-flows in pipes, having positive, negative and neutral buoyant particles, were analyzed and compared against appropriate terrestrial (1 g) data. In addition, microgravity bubbly flow data were also analyzed using the same two-fluid model. It was found that this two-fluid model was able to predict these data sets, including detailed predictions of the measured phasic velocity, dispersed phase volume fraction and turbulence (i.e., turbulent kinetic energy and Reynolds stress) fields. It was also found that the numerical algorithm, which was developed and used to evaluate the two-fluid model, was extremely efficient and could be easily run on a small PC. These results clearly demonstrate that a properly formulated two-fluid model, using mechanistically-based closure laws, can predict a wide range of multidimensional multiphase flow data without the need for 'tuners' and empirical correlations. Moreover, it appears that this approach can be used to develop and/or assess other flow-regime-specific closure laws for use in computational multiphase fluid dynamic (CMFD) solvers of transient two-fluid models, which, in turn, can be used for the design and analysis of various industrially important multiphase systems and processes. (authors)

  5. Effect of particle shape and slip mechanism on buoyancy induced convective heat transport with nanofluids

    Science.gov (United States)

    Joshi, Pranit Satish; Mahapatra, Pallab Sinha; Pattamatta, Arvind

    2017-12-01

    Experiments and numerical simulation of natural convection heat transfer with nanosuspensions are presented in this work. The investigations are carried out for three different types of nanosuspensions: namely, spherical-based (alumina/water), tubular-based (multi-walled carbon nanotube/water), and flake-based (graphene/water). A comparison with in-house experiments is made for all the three nanosuspensions at different volume fractions and for the Rayleigh numbers in the range of 7 × 105-1 × 107. Different models such as single component homogeneous, single component non-homogeneous, and multicomponent non-homogeneous are used in the present study. From the present numerical investigation, it is observed that for lower volume fractions (˜0.1%) of nanosuspensions considered, single component models are in close agreement with the experimental results. Single component models which are based on the effective properties of the nanosuspensions alone can predict heat transfer characteristics very well within the experimental uncertainty. Whereas for higher volume fractions (˜0.5%), the multi-component model predicts closer results to the experimental observation as it incorporates drag-based slip force which becomes prominent. The enhancement observed at lower volume fractions for non-spherical particles is attributed to the percolation chain formation, which perturbs the boundary layer and thereby increases the local Nusselt number values.

  6. Buoyancy Effect of Ionic Vacancy on the Change of the Partial Molar Volume in Ferricyanide-Ferrocyanide Redox Reaction under a Vertical Gravity Field

    Directory of Open Access Journals (Sweden)

    Yoshinobu Oshikiri

    2013-01-01

    Full Text Available With a gravity electrode (GE in a vertical gravity field, the buoyancy effect of ionic vacancy on the change of the partial molar volume in the redox reaction between ferricyanide (FERRI and ferrocyanide (FERRO ions was examined. The buoyancy force of ionic vacancy takes a positive or negative value, depending on whether the rate-determining step is the production or extinction of the vacancy. Though the upward convection over an upward electrode in the FERRO ion oxidation suggests the contribution of the positive buoyancy force arising from the vacancy production, the partial molar volume of the vacancy was not measured. On the other hand, for the downward convection under a downward electrode in the FERRI ion reduction, it was not completely but partly measured by the contribution of the negative buoyancy force from the vacancy extinction. Since the lifetime of the vacancy is decreased by the collision between ionic vacancies during the convection, the former result was ascribed to the shortened lifetime due to the increasing collision efficiency in the enhanced upward convection over an upward electrode, whereas the latter was thought to arise from the elongated lifetime due to the decreasing collision efficiency by the stagnation under the downward electrode.

  7. Studies of heat transfer having relevance to nuclear reactor containment cooling by buoyancy-driven air flow

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, J. D.; Li, J.; Wang, J. [The Univ., of Manchester, Manchester (United Kingdom)

    2003-07-01

    Two separate effects experiments concerned with buoyancy-influenced convective heat transfer in vertical passages which have relevance to the problem of nuclear reactor containment cooling by means of buoyancy-driven airflow are described. A feature of each is that local values of heat transfer coefficient are determined on surfaces maintained at uniform temperature. Experimental results are presented which highlight the need for buoyancy-induced impairment of turbulent convective heat transfer to be accounted for in the design of such passive cooling systems. A strategy is presented for predicting the heat removal by combined convective and radiative heat transfer from a full scale nuclear reactor containment shell using such experimental results.

  8. Buoyancy effects laminar slot jet impinging on a surface with constant heat flux

    International Nuclear Information System (INIS)

    Shokouhmand, H.; Esfahanian, V.; Masoodi, R.

    2004-01-01

    The two-dimensional laminar air jet issuing from a nozzle of half which terminates at height above a flat plate normal to the jet is numerically on the flow and thermal structure of the region near impingement. The impinging surface is maintained at a constant heat flux condition. The full Navier-Stocks and energy equations are solved by a finite difference method to evaluate the velocity profiles and temperature distribution. The governing parameters and their ranges are: Reynolds number Re, 10-50, Grashof number Gr, 0-50, Richardson number Ri=Gr/ Re 2 , Non dimensional nozzle height H,2-3. Results of the free streamline, local friction factor and heat transfer coefficient are graphically presented. It is found that enhancement of the heat transfer rate is substantial for high Richardson number conditions. Although the laminar jet impingement for isothermal condition has been already studied, however the constant heat flux has not been studied enough. the present paper will analyze a low velocity air jet, Which can be used for cooling of a simulated electronics package

  9. Academic Buoyancy Mediates Academic Anxiety's Effects on Learning Strategies: An Investigation of English- and Chinese-Speaking Australian Students

    Science.gov (United States)

    Collie, Rebecca J.; Ginns, Paul; Martin, Andrew J.; Papworth, Brad

    2017-01-01

    A primary goal our study was to explore whether relations between academic anxiety and students' use of a range of learning strategies (memorisation, elaboration, personal best [PB] goals and cooperation) were mediated by academic buoyancy. We were also interested in extending knowledge of anxiety and its role in students' learning strategy use.…

  10. Effect of Buoyancy on Forced Convection Heat Transfer in Vertical Channels - a Literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, A

    1965-03-15

    This report contains a short resume of the available information from various sources on the effect of free convection flow on forced convection heat transfer in vertical channels. Both theoretical and experimental investigations are included. Nearly all of the theoretical investigations are concerned with laminar flow with or without internal heat generation. More consistent data are available for upward flow than for downward flow. Curves are presented to determine whether free convection or forced convection mode of heat transfer is predominant for a particular Reynolds number and Rayleigh number. At Re{sub b} > 10{sup 5} free convection effects are negligible. Downward flow through a heated channel at low Reynolds number is unstable. Under similar conditions the overall heat transfer coefficient for downward flow tends to be higher than that for upward flow.

  11. Exercise Equipment: Neutral Buoyancy

    Science.gov (United States)

    Shackelford, Linda; Valle, Paul

    2016-01-01

    Load Bearing Equipment for Neutral Buoyancy (LBE-NB) is an exercise frame that holds two exercising subjects in position as they apply counter forces to each other for lower extremity and spine loading resistance exercises. Resistance exercise prevents bone loss on ISS, but the ISS equipment is too massive for use in exploration craft. Integrating the human into the load directing, load generating, and motion control functions of the exercise equipment generates safe exercise loads with less equipment mass and volume.

  12. Pancreatin-EDTA treatment affects buoyancy of cells in Cohn fraction V protein density gradients without residual effect on cell size.

    Science.gov (United States)

    Sheridan, J W; Simmons, R J

    1983-12-01

    The buoyancy of suspension-grown Mastocytoma P815 X-2 cells in albumin-rich Cohn fraction V protein (CFVP) density gradients was found to be affected by prior incubation of the cells in pancreatin-EDTA salt solution. Whereas in pH 5.2 CFVP, pancreatin-EDTA treated cells behaved as if of reduced density when compared with the control 'undigested' group, in pH 7.3 CFVP they behaved as if of increased density. By contrast, pancreatin-EDTA treatment had no effect on the buoyancy of mastocytoma cells in polyvinylpyrrolidone-coated colloidal silica (PVP-CS, Percoll T.M.) density gradients of either pH 5.2 or pH 7.3. As cell size determinations failed to reveal alterations in cell size either as a direct result of pancreatin-EDTA treatment or as a combined consequence of such treatment and exposure to CFVP either with or without centrifugation, a mechanism involving a change in cell density other than during the centrifugation process itself seems unlikely. Binding studies employing 125I-CFVP, although indicating that CFVP bound to cells at 4 degrees, failed to reveal a pancreatin-EDTA treatment-related difference in the avidity of this binding. Although the mechanism of the pancreatin-EDTA-induced buoyancy shift in CFVP remains obscure, the absence of such an effect in PVP-CS suggests that the latter cell separation solution may more accurately be used to determine cell density.

  13. Numerical investigations of buoyancy-driven natural ventilation in a simple atrium building and its effect on the thermal comfort conditions

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2012-01-01

    In the present study use of solar-assisted buoyancy-driven natural ventilation in a simple atrium building is explored numerically with particular emphasis on the thermal comfort conditions in the building. Initially various geometric configurations of the atrium space were considered in order to investigate airflows and temperature distributions in the building using a validated computational fluid dynamics (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modelling approach with the SST-k–ω turbulence model and the Discrete Transfer Radiation Model (DTRM) was used for the investigations. The steady-state governing equations were solved using a commercial CFD solver FLUENT © . From the numerical results obtained, it was noted that an atrium space integrated with a solar chimney would be a relatively better option to be used in an atrium building. In the geometry selected, the performance of the building in response to various changes in design parameters was investigated. The produced airflows and temperature distributions were then used to evaluate indoor thermal comfort conditions in terms of the thermal comfort indices, i.e. the well-known predicted mean vote (PMV) index, its modifications especially for natural ventilation, predicted percent dissatisfied (PPD) index and Percent dissatisfied (PD) factor due to draft. It was found that the thermal conditions in the occupied areas of the building developed as a result of the use of solar-assisted buoyancy-driven ventilation for the particular values of the design parameters selected are mostly in the comfortable zone. Finally, it is demonstrated that the proposed methodology leads to reliable thermal comfort predictions, while the effect of various design variables on the performance of the building is easily recognized. - Highlights: ► Numerical investigations were carried for the use of buoyancy-driven displacement ventilation in a simple atrium building. ► Effect of various atrium

  14. Wave Dragon Buoyancy Regulation Study

    DEFF Research Database (Denmark)

    Jakobsen, Jens; Kofoed, Jens Peter

    Wave Dragon is a wave energy converter, which was deployed offshore at Nissum Bredning in Denmark in 2003. The experience gained from operating Wave Dragon during 2003 and 2004 has shown that the buoyancy regulation system can be improved in a number of ways. This study describes the current...

  15. The Competition Between a Localised and Distributed Source of Buoyancy

    Science.gov (United States)

    Partridge, Jamie; Linden, Paul

    2012-11-01

    We propose a new mathematical model to study the competition between localised and distributed sources of buoyancy within a naturally ventilated filling box. The main controlling parameters in this configuration are the buoyancy fluxes of the distributed and local source, specifically their ratio Ψ. The steady state dynamics of the flow are heavily dependent on this parameter. For large Ψ, where the distributed source dominates, we find the space becomes well mixed as expected if driven by an distributed source alone. Conversely, for small Ψ we find the space reaches a stable two layer stratification. This is analogous to the classical case of a purely local source but here the lower layer is buoyant compared to the ambient, due to the constant flux of buoyancy emanating from the distributed source. The ventilation flow rate, buoyancy of the layers and also the location of the interface height, which separates the two layer stratification, are obtainable from the model. To validate the theoretical model, small scale laboratory experiments were carried out. Water was used as the working medium with buoyancy being driven directly by temperature differences. Theoretical results were compared with experimental data and overall good agreement was found. A CASE award project with Arup.

  16. Gravity modulation effect on the onset of thermal buoyancy convection in a horizontal layer of the Oldroyd fluid

    Energy Technology Data Exchange (ETDEWEB)

    Lyubimova, Tatyana; Kovalevskaya, Kseniya, E-mail: lyubimovat@mail.ru [Institute of Continuous Media Mechanics UB RAS, Perm (Russian Federation)

    2016-12-15

    The effect of gravity modulation on the onset of convection in a horizontal layer of viscoelastic Oldroyd fluid heated from below is considered. The analytical solution of the problem has been obtained for the case of stress-free boundaries and rectangular modulation. It has been shown that depending on the parameter values, the modulation can produce either stabilizing or destabilizing effects. The deformation retardation always exerts a stabilizing effect, which is most pronounced in the shortwave range. The numerical results obtained by the solution of full nonlinear problems agree well with the results of linear stability analysis. (paper)

  17. The effect of buoyancy on flow and heat transfer for a gas passing down a vertical pipe at low turbulent reynolds numbers

    International Nuclear Information System (INIS)

    Easby, J.P.

    1978-01-01

    For the analysis of low-flow situations in the core of the High-Temperature Gas-Cooled reactor it is necessary to have a knowledge of the variation of pressure drop and heat transfer with flow and buoyancy influence. Nitrogen at 4 bar has been used to simulate the high pressure helium in the reactor and an experiment performed for downward flow in a heated vertical pipe. The measurements show that for the range of flow and buoyancy influence parameters investigated, (2000 6 ), friction factors are reduced by up to 20% compared with a correlation for isothermal flows and heat transfer is increased by up to 40% compared with a correlation for constant fluid properties. Agreement with the limit amount of previous data is quite satisfactory. The changes in heat transfer and friction factor with buoyancy influence can be attributed to distortion of the normally linear, radial shear stress profile. Simple equations have been determined to correlate the present results but extrapolation to conditions of high flow and buoyancy influence, where the interaction of forced and free convection may be different, is not advised. (author)

  18. Influences of buoyancy and thermal boundary conditions on heat transfer with naturally-induced flow

    International Nuclear Information System (INIS)

    Jackson, J.D.; Li, J.

    2002-01-01

    A fundamental study is reported of heat transfer from a vertical heated tube to air which is induced naturally upwards through it by the action of buoyancy. Measurements of local heat transfer coefficient were made using a specially designed computer-controlled power supply and measurement system for conditions of uniform wall temperature and uniform wall heat flux. The effectiveness of heat transfer proved to be much lower than for conditions of forced convection. It was found that the results could be correlated satisfactorily when presented in terms of dimensionless parameters similar to those used for free convection heat transfer from vertical surfaces provided that the heat transfer coefficients were evaluated using local fluid bulk temperature calculated utilising the measured values of flow rate induced through the system. Additional experiments were performed' with pumped flow. These covered the entire mixed convection region. It was found that the data for naturally-induced flow mapped onto the pumped flow data when presented in terms of Nusselt number ratio (mixed to forced) and buoyancy parameter. Computational simulations of the experiments were performed using an advanced computer code which incorporated a buoyancy-influenced, variable property, developing wall shear flow formulation and a low Reynolds number k-ε turbulence model. These reproduced observed behaviour quite well. (author)

  19. 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

  20. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans.

    Science.gov (United States)

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature. From specific gravity measurements of marine fish eggs salinity appears to be the only determinant of the buoyancy indicating that the thermal expansions of the fish egg and the ambient seawater are equal. We analyze the mechanisms behind thermal expansion in fish eggs in order to determine to what extent it can be justified to neglect the effects of temperature on buoyancy. Our results confirm the earlier assumptions that salinity is the basic determinant on buoyancy in marine fish eggs that, in turn, influence the vertical distributions and, consequently, the dispersal of fish eggs from the spawning areas. Fish populations have adapted accordingly by producing egg specific gravities that tune the egg buoyancy to create specific vertical distributions for each local population. A wide variety of buoyancy adaptations are found among fish populations. The ambient physical conditions at the spawning sites form a basic constraint for adaptation. In coastal regions where salinity increases with depth, and where the major fraction of the fish stocks spawns, pelagic and mesopelagic egg distributions dominate. However, in the larger part of worlds' oceans salinity decreases with depth resulting in different egg distributions. Here, the principles of vertical distributions of fish eggs in the world oceans are presented in an overarching framework presenting the basic differences between regions, mainly coastal, where salinity increases with depth and the major part of the world oceans where salinity decreases with depth. We show that under these latter conditions, steady-state vertical distribution of mesopelagic fish eggs cannot exist as it does in most coastal regions. In fact, a critical spawning depth must exist where spawning below this depth threshold results in eggs sinking out of the water column and become lost for

  1. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans

    Science.gov (United States)

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature. From specific gravity measurements of marine fish eggs salinity appears to be the only determinant of the buoyancy indicating that the thermal expansions of the fish egg and the ambient seawater are equal. We analyze the mechanisms behind thermal expansion in fish eggs in order to determine to what extent it can be justified to neglect the effects of temperature on buoyancy. Our results confirm the earlier assumptions that salinity is the basic determinant on buoyancy in marine fish eggs that, in turn, influence the vertical distributions and, consequently, the dispersal of fish eggs from the spawning areas. Fish populations have adapted accordingly by producing egg specific gravities that tune the egg buoyancy to create specific vertical distributions for each local population. A wide variety of buoyancy adaptations are found among fish populations. The ambient physical conditions at the spawning sites form a basic constraint for adaptation. In coastal regions where salinity increases with depth, and where the major fraction of the fish stocks spawns, pelagic and mesopelagic egg distributions dominate. However, in the larger part of worlds’ oceans salinity decreases with depth resulting in different egg distributions. Here, the principles of vertical distributions of fish eggs in the world oceans are presented in an overarching framework presenting the basic differences between regions, mainly coastal, where salinity increases with depth and the major part of the world oceans where salinity decreases with depth. We show that under these latter conditions, steady-state vertical distribution of mesopelagic fish eggs cannot exist as it does in most coastal regions. In fact, a critical spawning depth must exist where spawning below this depth threshold results in eggs sinking out of the water column and become lost

  2. 14 CFR 29.755 - Hull buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull buoyancy. 29.755 Section 29.755... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.755 Hull buoyancy. Water-based and amphibian rotorcraft. The hull and auxiliary floats, if used, must have enough...

  3. Analysis of Buoyancy Module Auxiliary Installation Technology Based on Numerical Simulation

    Science.gov (United States)

    Xu, Songsen; Jiao, Chunshuo; Ning, Meng; Dong, Sheng

    2018-04-01

    To reduce the requirement for lifting capacity and decrease the hoist cable force during the descending and laying process of a subsea production system (SPS), a buoyancy module auxiliary installation technology was proposed by loading buoyancy modules on the SPS to reduce the lifting weight. Two models are established, namely, the SPS lowering-down model and the buoyancy module floating-up model. The main study results are the following: 1) When the buoyancy module enters the water under wave condition, the amplitude of tension fluctuation is twice that when SPS enters water; 2) Under current condition, the displacement of SPS becomes three times larger because of the existence of the buoyancy module; 3) After being released, the velocity of the buoyancy module increases to a large speed rapidly and then reaches a balancing speed gradually. The buoyancy module floats up at a balancing speed and rushes out from the water at a pop-up distance; 4) In deep water, the floating-up velocity of the buoyancy module is related to its mass density and shape, and it is not related to water depth; 5) A drag parachute can reduce floating-up velocity and pop-up distance effectively. Good agreement was found between the simulation and experiment results.

  4. Effects of Buoyancy Forces on Immiscible Water/Oil Displacements in a Vertically Oriented Porous Medium Effets des facteurs de flottabilité sur les déplacements non-miscibles eau/huile dans un milieu poreux vertical

    Directory of Open Access Journals (Sweden)

    Thirunavu S. R.

    2006-11-01

    Full Text Available The effects of buoyancy forces on liquid-liquid displacement processes occurring in porous media are important in a variety of practical situations, in particular during the displacement of oil from partially-depleted underground reservoirs by means of aqueous solutions. Most previous studies involving the visualization of water/oil displacements in porous media have been undertaken in horizontal two-dimensional porous medium cells. The objective of the present work was to determine the effects of buoyancy forces; on the fingering pattern and oil recovery by conducting immiscible displacement experiments in two-dimensional consolidated porous medium cells aligned in the vertical plane. In order to obtain a clear understanding of the favourable and unfavourable effects of buoyancy forces, experiments were carried out in three different flow modes, namely horizontal, vertical upward, and vertical downward. As the effects of buoyancy forces are negligible for two-dimensional porous media in the horizontal flow mode, the recoveries obtained in this mode were used as a reference for comparison with those obtained in the two vertical modes. Displacements using five different density ratios were studied. The breakthrough time and percentage oil recovery were measured in each case. The effects of buoyancy forces, viscous forces, and capillary forces, as well as the injection flow rate, were also recorded. The results obtained indicate that the effects of buoyancy forces are very pronounced at low flow rates and low oil/water density ratios, and that even a slight increase in the flow rate causes the buoyancy forces to rapidly become less significant. Les facteurs de flottabilité exercent un effet important sur les déplacements liquide/liquide en milieu poreux dans toute une gamme de situations pratiques, en particulier lorsqu'on veut déplacer l'huile de roches réservoirs partiellement épuisées à l'aide de solutions aqueuses. La plupart des

  5. Buoyancy Regulation and the Energetics of Diving in Dolphins Seals, Sea Lions and Sea Otters

    National Research Council Canada - National Science Library

    Costa, Daniel

    1998-01-01

    We examined swim speed and ascent descent rates in sea lions and elephant seals in order to make comparisons in their diving strategies and how these may be effected by different strategies of buoyancy regulation...

  6. Influence of local capillary trapping on containment system effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

    2014-03-31

    Immobilization of CO2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence of injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO2 migration can be represented as a single value of “critical capillary entry pressure” Pc,entrycrit, such that cells with capillary entry pressure greater/less than Pc,entrycrit act as barriers/potential traps during CO2 migration. At intermediate values of Pc,entrycrit, the barrier regions become more laterally extensive in the reservoir

  7. SuperLig Ion Exchange Resin Swelling and Buoyancy Study

    International Nuclear Information System (INIS)

    Hassan, N.M.

    2000-01-01

    The objective of this study was to achieve a fundamental understanding of SuperLig resin swelling and shrinking characteristics, which lead to channeling and early breakthrough during loading cycles. The density of salt solution that causes resin floating was also determined to establish a limit for operation. Specific tests performed include (a) pH dependence, (b) ionic strength dependence and (c) buoyancy effect vs. simulant composition

  8. THE INFLUENCE OF BUOYANCY ON FLOW AND POLLUTANT DISPERSION IN STREET CANYONS

    OpenAIRE

    Buccolieri, Riccardo; Pulvirenti, Beatrice; Di Sabatino, Silvana; Britter, Rex

    2008-01-01

    Abstract: In this paper, the effect of buoyancy on flow and pollutant dispersion within street canyons is studied by means of computational fluid dynamics simulations. We consider a neutral boundary layer approaching a 3D street canyon assuming a wind direction perpendicular to the street canyon. The Boussinesq hypothesis for incompressible fluids is chosen for modelling buoyancy. We distinguish three cases: leeward, ground and windward wall heating. Thermal effects on both the flow ...

  9. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target.

    Science.gov (United States)

    Dubey, P K; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  10. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    Science.gov (United States)

    Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  11. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    International Nuclear Information System (INIS)

    Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-01-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique

  12. BUOYANCY INSTABILITIES IN A WEAKLY COLLISIONAL INTRACLUSTER MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Matthew W.; Stone, James M. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States); Bogdanovic, Tamara; Reynolds, Christopher S., E-mail: kunz@astro.princeton.edu, E-mail: jstone@astro.princeton.edu, E-mail: tamarab@astro.umd.edu, E-mail: chris@astro.umd.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2012-08-01

    The intracluster medium (ICM) of galaxy clusters is a weakly collisional plasma in which the transport of heat and momentum occurs primarily along magnetic-field lines. Anisotropic heat conduction allows convective instabilities to be driven by temperature gradients of either sign: the magnetothermal instability (MTI) in the outskirts of clusters and the heat-flux buoyancy-driven instability (HBI) in their cooling cores. We employ the Athena magnetohydrodynamic code to investigate the nonlinear evolution of these instabilities, self-consistently including the effects of anisotropic viscosity (i.e., Braginskii pressure anisotropy), anisotropic conduction, and radiative cooling. We find that, in all but the innermost regions of cool-core clusters, anisotropic viscosity significantly impairs the ability of the HBI to reorient magnetic-field lines orthogonal to the temperature gradient. Thus, while radio-mode feedback appears necessary in the central few Multiplication-Sign 10 kpc, heat conduction may be capable of offsetting radiative losses throughout most of a cool core over a significant fraction of the Hubble time. Magnetically aligned cold filaments are then able to form by local thermal instability. Viscous dissipation during cold filament formation produces accompanying hot filaments, which can be searched for in deep Chandra observations of cool-core clusters. In the case of MTI, anisotropic viscosity leads to a nonlinear state with a folded magnetic field structure in which field-line curvature and field strength are anti-correlated. These results demonstrate that, if the HBI and MTI are relevant for shaping the properties of the ICM, one must self-consistently include anisotropic viscosity in order to obtain even qualitatively correct results.

  13. Radioprotective effect of local hypothermia

    International Nuclear Information System (INIS)

    Hong, Seong-Su; Ogawa, Yoshihiro; Higano, Shuichi; Nakamura, Mamoru; Hoshino, Fumihiko

    1985-01-01

    We attempted local hypothermia to prevent radiation dermatitis and stomatitis. With regard to parasternal skin reactions postoperatively irradiated breast cancer, dry and moist desquamation, which occasionally occurred with conventional irradiation was not observed in combination with local cooling. As for head and neck tumors, patients who complained of stomatitis decreased with the local cooling, and no one wanted a pause in irradiation before 40 Gy. As local hypothermia is free from danger and does not require special equipment, it was considered to be widely applicable. (author)

  14. An Analysis of Tax Buoyancy Rates

    Directory of Open Access Journals (Sweden)

    Farooq Rasheed

    2006-10-01

    Full Text Available By using econometric techniques for estimating tax elasticities, this paper findssignificant but low tax buoyancy rates for GDP, M0 and volume of trade. Surprisingly,the theoretically important factor of tax evasion (SFTR was found to be ineffective. Thisindicates that SFTR is not an adequate measure of tax evasion. There is no significantassociation between tax revenue growth and investment, credit, public debt and inflation.This illustrates the weakness of the tax regime in Pakistan.

  15. Buoyancy frequency profiles and internal semidiurnal tide turning depths in the oceans

    NARCIS (Netherlands)

    King, B.; Stone, M.; Zhang, H.P.; Gerkema, T.; Marder, M.; Scott, R.B.; Swinney, H.L.

    2012-01-01

    We examine the possible existence of internal gravity wave "turning depths," depths below which the local buoyancy frequency N(z) becomes smaller than the wave frequency. At a turning depth, incident gravity waves reflect rather than reaching the ocean bottom as is generally assumed. Here we

  16. Energy spectrum of buoyancy-driven turbulence

    KAUST Repository

    Kumar, Abhishek

    2014-08-25

    Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Πu, we demonstrate that, for stably stratified flows, the kinetic energy spectrum Eu(k)∼k-11/5, the potential energy spectrum Eθ(k)∼k-7/5, and Πu(k)∼k-4/5 are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential energy by buoyancy. For weaker buoyancy, this conversion is weak, hence Eu(k) follows Kolmogorov\\'s spectrum with a constant energy flux. For Rayleigh-Bénard convection, we show that the energy supply rate by buoyancy is positive, which leads to an increasing Πu(k) with k, thus ruling out Bolgiano-Obukhov scaling for the convective turbulence. Our numerical results show that convective turbulence for unit Prandt number exhibits a constant Πu(k) and Eu(k)∼k-5/3 for a narrow band of wave numbers. © 2014 American Physical Society.

  17. Region effects influence local tree species diversity.

    Science.gov (United States)

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  18. Buoyancy Driven Natural Ventilation through Horizontal Openings

    OpenAIRE

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions...

  19. Feedback mechanisms of shallow convective clouds in a warmer climate as demonstrated by changes in buoyancy

    Science.gov (United States)

    Dagan, G.; Koren, I.; Altaratz, O.; Feingold, G.

    2018-05-01

    Cloud feedbacks could influence significantly the overall response of the climate system to global warming. Here we study the response of warm convective clouds to a uniform temperature change under constant relative humidity (RH) conditions. We show that an increase in temperature drives competing effects at the cloud scale: a reduction in the thermal buoyancy term and an increase in the humidity buoyancy term. Both effects are driven by the increased contrast in the water vapor content between the cloud and its environment, under warming with constant RH. The increase in the moisture content contrast between the cloud and its environment enhances the evaporation at the cloud margins, increases the entrainment, and acts to cool the cloud. Hence, there is a reduction in the thermal buoyancy term, despite the fact that theoretically this term should increase.

  20. Flows and Stratification of an Enclosure Containing Both Localised and Vertically Distributed Sources of Buoyancy

    Science.gov (United States)

    Partridge, Jamie; Linden, Paul

    2013-11-01

    We examine the flows and stratification established in a naturally ventilated enclosure containing both a localised and vertically distributed source of buoyancy. The enclosure is ventilated through upper and lower openings which connect the space to an external ambient. Small scale laboratory experiments were carried out with water as the working medium and buoyancy being driven directly by temperature differences. A point source plume gave localised heating while the distributed source was driven by a controllable heater mat located in the side wall of the enclosure. The transient temperatures, as well as steady state temperature profiles, were recorded and are reported here. The temperature profiles inside the enclosure were found to be dependent on the effective opening area A*, a combination of the upper and lower openings, and the ratio of buoyancy fluxes from the distributed and localised source Ψ =Bw/Bp . Industrial CASE award with ARUP.

  1. Release of radon contaminants from Yucca Mountain: The role of buoyancy driven flow

    International Nuclear Information System (INIS)

    Sullivan, T.M.; Pescatore, C.

    1994-02-01

    The potential for the repository heat source to promote buoyancy driven flow and thereby cause release of radon gas out of Yucca Mountain has been examined through a critical review of the theoretical and experimental studies of this process. The review indicates that steady-state buoyancy enhanced release of natural radon and other contaminant gases should not be a major concern at Yucca Mountain. Barometric pumping and wind pumping are identified as two processes that will have a potentially greater effect on surface releases of gases

  2. Localization effects in heavy ion collisions

    International Nuclear Information System (INIS)

    Donangelo, R.J.

    1984-01-01

    Radial and angular localization in heavy ion reactions on deformed nuclei is discussed. A theoretical method appropriate to study these localization effects is briefly described and then applied to the determination of deformed heavy ion potentials from inclastic scattering data. It is argued that one-and two-nucleon transfer reactions on deformed nuclei can provide a probe of nuclear structure in high angular momentum states and be at least qualitatively analyzed in the light of these localization concepts. (Author) [pt

  3. Investigating Students' Ideas About Buoyancy and the Influence of Haptic Feedback

    Science.gov (United States)

    Minogue, James; Borland, David

    2016-04-01

    While haptics (simulated touch) represents a potential breakthrough technology for science teaching and learning, there is relatively little research into its differential impact in the context of teaching and learning. This paper describes the testing of a haptically enhanced simulation (HES) for learning about buoyancy. Despite a lifetime of everyday experiences, a scientifically sound explanation of buoyancy remains difficult to construct for many. It requires the integration of domain-specific knowledge regarding density, fluid, force, gravity, mass, weight, and buoyancy. Prior studies suggest that novices often focus on only one dimension of the sinking and floating phenomenon. Our HES was designed to promote the integration of the subconcepts of density and buoyant forces and stresses the relationship between the object itself and the surrounding fluid. The study employed a randomized pretest-posttest control group research design and a suite of measures including an open-ended prompt and objective content questions to provide insights into the influence of haptic feedback on undergraduate students' thinking about buoyancy. A convenience sample (n = 40) was drawn from a university's population of undergraduate elementary education majors. Two groups were formed from haptic feedback (n = 22) and no haptic feedback (n = 18). Through content analysis, discernible differences were seen in the posttest explanations sinking and floating across treatment groups. Learners that experienced the haptic feedback made more frequent use of "haptically grounded" terms (e.g., mass, gravity, buoyant force, pushing), leading us to begin to build a local theory of language-mediated haptic cognition.

  4. Local effects of living windbreaks

    International Nuclear Information System (INIS)

    Souto, L.F.M.A.R.; Meneses, J.F.

    2004-01-01

    The primary purpose of living windbreaks is the reduction of the wind speed. Changes in the velocity and direction of airflow lead to changes in the microclimate. Microclimate is the result of various interacting factors, most of which can be affected by shelter at detectable levels. The effectiveness of windbreaks depends upon their internal and external structure. The most important structural feature is porosity. Maximum wind reductions are closely related to low porosity. However, barriers with low porosity generate more turbulence to leeward then medium or high ones. The horizontal extent of windbreak effects is proportional to windbreak height (h). Wind reductions are detectable on the windward side of the barrier from 2 h to 5 h, and extend to leeward about 20 h, if significant reductions of the normal wind speed (10% - 30%) occur. The principal effects of natural windbreaks on microclimate are reviewed. These are: wind speed, turbulence and their dependence on the porosity and height of the barrier; solar and thermal radiation around the windbreak; air temperature during the day and at night; humidity and snow deposition. Complementary effects of windbreaks are discussed, such as wind and hydraulic erosion, crop protection and plant growth, livestock protection of buildings and people. Disadvantages of windbreaks result from tree-crop competition and pests. Windbreaks allow the practice of agriculture in many regions of the world, namely on island and coastal areas, which are particularly sensitive due to the high wind speeds and salt content of the wind. Windbreaks contribute to sustainable agricultural systems by maintaining biological diversity and improving the aesthetic value of the landscape. A better understanding of their dynamics will certainly contribute to the improvement of sheltered areas and to the establishment of more efficient windbreaks, with less negative impacts to the countryside

  5. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  6. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  7. Astronaut Training in the Neutral Buoyancy Simulator

    Science.gov (United States)

    1993-01-01

    This photograph shows an STS-61 astronaut training for the Hubble Space Telescope (HST) servicing mission (STS-61) in the Marshall Space Flight Center's (MSFC's) Neutral Buoyancy Simulator (NBS). Two months after its deployment in space, scientists detected a 2-micron spherical aberration in the primary mirror of the HST that affected the telescope's ability to focus faint light sources into a precise point. This imperfection was very slight, one-fiftieth of the width of a human hair. A scheduled Space Service servicing mission (STS-61) in 1993 permitted scientists to correct the problem. The MSFC NBS provided an excellent environment for testing hardware to examine how it would operate in space and for evaluating techniques for space construction and spacecraft servicing.

  8. Buoyancy frequency profiles and internal semidiurnal tide turning depths in the oceans

    OpenAIRE

    King, B.; Stone, M.; Zhang, H.P.; Gerkema, T.; Marder, M.; Scott, R.B.; Swinney, H.L.

    2012-01-01

    We examine the possible existence of internal gravity wave "turning depths," depths below which the local buoyancy frequency N(z) becomes smaller than the wave frequency. At a turning depth, incident gravity waves reflect rather than reaching the ocean bottom as is generally assumed. Here we consider internal gravity waves at the lunar semidiurnal (M-2) tidal frequency, omega(M2). Profiles of N-2(z) (the quantity in the equations of motion) are computed using conductivity, temperature, and de...

  9. Surface Buoyancy Fluxes and the Strength of the Subpolar Gyre

    Science.gov (United States)

    Hogg, A. M.; Gayen, B.

    2017-12-01

    Midlatitude ocean gyres have long been considered to be driven by the mechanical wind stress on the ocean's surface (strictly speaking, the potential vorticity input from wind stress curl). However, surface buoyancy forcing (i.e. heating/cooling or freshening/salinification) also modifies the potential vorticity at the surface. Here, we present a simple argument to demonstrate that ocean gyres may (in principle) be driven by surface buoyancy forcing. This argument is derived in two ways: A Direct Numerical Simulation, driven purely by buoyancy forcing, which generates strong nonlinear gyers in the absence of wind stress; and A series of idealised eddy-resolving numerical ocean model simulations, in which wind stress and buoyancy flux are varied independently and together, are used to understand the relative importance of these two types of forcing. In these simulations, basin-scale gyres and western boundary currents with realistic magnitudes, remain even in the absence of mechanical forcing by surface wind stress. These results support the notion that surface buoyancy forcing can reorganise the potential vorticity in the ocean in such a way as to drive basin-scale gyres. The role of buoyancy is stronger in the subpolar gyre than in the subtropical gyre. We infer that surface buoyancy fluxes are likely to play a contributing role in governing the strength, variability and predictability of the North Atlantic subpolar gyre.

  10. Processes governing transient responses of the deep ocean buoyancy budget to a doubling of CO2

    Science.gov (United States)

    Palter, J. B.; Griffies, S. M.; Hunter Samuels, B. L.; Galbraith, E. D.; Gnanadesikan, A.

    2012-12-01

    Recent observational analyses suggest there is a temporal trend and high-frequency variability in deep ocean buoyancy in the last twenty years, a phenomenon reproduced even in low-mixing models. Here we use an earth system model (GFDL's ESM2M) to evaluate physical processes that influence buoyancy (and thus steric sea level) budget of the deep ocean in quasi-steady state and under a doubling of CO2. A new suite of model diagnostics allows us to quantitatively assess every process that influences the buoyancy budget and its temporal evolution, revealing surprising dynamics governing both the equilibrium budget and its transient response to climate change. The results suggest that the temporal evolution of the deep ocean contribution to sea level rise is due to a diversity of processes at high latitudes, whose net effect is then advected in the Eulerian mean flow to mid and low latitudes. In the Southern Ocean, a slowdown in convection and spin up of the residual mean advection are approximately equal players in the deep steric sea level rise. In the North Atlantic, the region of greatest deep steric sea level variability in our simulations, a decrease in mixing of cold, dense waters from the marginal seas and a reduction in open ocean convection causes an accumulation of buoyancy in the deep subpolar gyre, which is then advected equatorward.

  11. Experimental aspects of buoyancy correction in measuring reliable highpressure excess adsorption isotherms using the gravimetric method.

    Science.gov (United States)

    Nguyen, Huong Giang T; Horn, Jarod C; Thommes, Matthias; van Zee, Roger D; Espinal, Laura

    2017-12-01

    Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO 2 and supercritical N 2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

  12. Buoyancy flow in fractures intersecting a nuclear waste repository

    International Nuclear Information System (INIS)

    Wang, J.S.Y.; Tsang, C.F.

    1980-07-01

    The thermally induced buoyancy flow in fractured rocks around a nuclear waste repository is of major concern in the evaluation of the regional, long-term impact of nuclear waste disposal in geological formation. In this study, buoyancy flow and the development of convective cells are calculated in vertical fractures passing through or positioned near a repository. Interaction between buoyancy flow and regional hydraulic gradient is studied as a function of time, and the interference of intersecting fractures with each other is also discussed

  13. Homogeneous purely buoyancy driven turbulent flow

    Science.gov (United States)

    Arakeri, Jaywant; Cholemari, Murali; Pawar, Shashikant

    2010-11-01

    An unstable density difference across a long vertical tube open at both ends leads to convection that is axially homogeneous with a linear density gradient. We report results from such tube convection experiments, with driving density caused by salt concentration difference or temperature difference. At high enough Rayleigh numbers (Ra) the convection is turbulent with zero mean flow and zero mean Reynolds shear stresses; thus turbulent production is purely by buoyancy. We observe different regimes of turbulent convection. At very high Ra the Nusselt number scales as the square root of the Rayleigh number, giving the so-called "ultimate regime" of convection predicted for Rayleigh-Benard convection in limit of infinite Ra. Turbulent convection at intermediate Ra, the Nusselt number scales as Ra^0.3. In both regimes, the flux and the Taylor scale Reynolds number are more than order of magnitude larger than those obtained in Rayleigh-Benard convection. Absence of a mean flow makes this an ideal flow to study shear free turbulence near a wall.

  14. Effect of Cattaneo-Christov heat flux on buoyancy MHD nanofluid flow and heat transfer over a stretching sheet in the presence of Joule heating and thermal radiation impacts

    Science.gov (United States)

    Dogonchi, A. S.; Ganji, D. D.

    2018-06-01

    In this study, buoyancy MHD nanofluid flow and heat transfer over a stretching sheet in the presence of Joule heating and thermal radiation impacts, are studied. Cattaneo-Christov heat flux model instead of conventional Fourier's law of heat conduction is applied to investigate the heat transfer characteristics. A similarity transformation is used to transmute the governing momentum and energy equations into non-linear ordinary differential equations with the appropriate boundary conditions. The obtained non-linear ordinary differential equations are solved numerically. The impacts of diverse active parameters such as the magnetic parameter, the radiation parameter, the buoyancy parameter, the heat source parameter, the volume fraction of nanofluid and the thermal relaxation parameter are examined on the velocity and temperature profiles. In addition, the value of the Nusselt number is calculated and presented through figures. The results demonstrate that the temperature profile is lower in the case of Cattaneo-Christov heat flux model as compared to Fourier's law. Moreover, the Nusselt number raises with the raising volume fraction of nanofluid and it abates with the ascending the radiation parameter.

  15. A sharp interface immersed boundary method for vortex-induced vibration in the presence of thermal buoyancy

    Science.gov (United States)

    Garg, Hemanshul; Soti, Atul K.; Bhardwaj, Rajneesh

    2018-02-01

    We report the development of an in-house fluid-structure interaction solver and its application to vortex-induced vibration (VIV) of an elastically mounted cylinder in the presence of thermal buoyancy. The flow solver utilizes a sharp interface immersed boundary method, and in the present work, we extend it to account for the thermal buoyancy using Boussinesq approximation and couple it with a spring-mass system of the VIV. The one-way coupling utilizes an explicit time integration scheme and is computationally efficient. We present benchmark code verifications of the solver for natural convection, mixed convection, and VIV. In addition, we verify a coupled VIV-thermal buoyancy problem at a Reynolds number, Re = 150. We numerically demonstrate the onset of the VIV in the presence of the thermal buoyancy for an insulated cylinder at low Re. The buoyancy is induced by two parallel plates, kept in the direction of flow and symmetrically placed around the cylinder. The plates are maintained at the hot and cold temperature to the same degree relative to the ambient. In the absence of the thermal buoyancy (i.e., the plates are at ambient temperature), the VIV does not occur for Re ≤ 20 due to stable shear layers. By contrast, the thermal buoyancy induces flow instability and the vortex shedding helps us to achieve the VIV at Re ≤ 20, lower than the critical value of Re (≈21.7), reported in the literature, for a self-sustained VIV in the absence of the thermal buoyancy. The present simulations show that the lowest Re to achieve VIV in the presence of the thermal buoyancy is around Re ≈ 3, at Richardson number, Ri = 1. We examine the effect of the reduced velocity (UR), mass ratio (m), Prandtl number (Pr), Richardson number (Ri) on the displacement of the cylinder, lift coefficient, oscillation frequency, the phase difference between displacement and lift force, and wake structures. We obtain a significantly larger vibration amplitude of the cylinder over a wide

  16. Buoyancy Induced Heat Transfer and Fluid Flow Inside a Prismatic Cavity

    International Nuclear Information System (INIS)

    Aich, Walid; Omri, Ahmed; Ben Nasrallah, Sassi

    2009-01-01

    This paper deals with a numerical simulation of natural convection flows in a prismatic cavity. This configuration represents solar energy collectors, conventional attic spaces of greenhouses and buildings with pitched roofs. The third dimension of the cavity is considered long enough for the flow to be considered 2D. The base is submitted to a uniform heat flux, the two top inclined walls are symmetrically cooled and the two vertical walls are assumed to be perfect thermal insulators. The aim of the study is to examine the thermal exchange by natural convection and effects of buoyancy forces on flow structure. The study provides useful information on the flow structure sensitivity to the governing parameters, the Rayleigh number (Ra) and the aspect ratio of the cavity. The hydrodynamic and thermal fields, the local Nusselt number, the temperature profile at the bottom and at the center of the cavity are investigated for a large range of Ra. The effect of the aspect ratio is examined for different values of Ra. Based on the authors knowledge, no previous results on natural convection in this geometry exist

  17. Semi-Empirical Models for Buoyancy-Driven Ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2015-01-01

    A literature study is presented on the theories and models dealing with buoyancy-driven ventilation in rooms. The models are categorised into four types according to how the physical process is conceived: column model, fan model, neutral plane model and pressure model. These models are analysed...... and compared with a reference model. Discrepancies and differences are shown, and the deviations are discussed. It is concluded that a reliable buoyancy model based solely on the fundamental flow equations is desirable....

  18. Is academic buoyancy anything more than adaptive coping?

    Science.gov (United States)

    Putwain, David W; Connors, Liz; Symes, Wendy; Douglas-Osborn, Erica

    2012-05-01

    Academic buoyancy refers to a positive, constructive, and adaptive response to the types of challenges and setbacks experienced in a typical and everyday academic setting. In this project we examined whether academic buoyancy explained any additional variance in test anxiety over and above that explained by coping. Two hundred and ninety-eight students in their final two years of compulsory schooling completed self-report measures of academic buoyancy, coping, and test anxiety. Results suggested that buoyancy was inversely related to test anxiety and unrelated to coping. With the exception of test-irrelevant thoughts, test anxiety was positively related to avoidance coping and social support. Test-irrelevant thoughts were inversely related to task focus, unrelated to social support, and positively related to avoidance. A hierarchical regression analysis showed that academic buoyancy explained a significant additional proportion of variance in test anxiety when the variance for coping had already been accounted for. These findings suggest that academic buoyancy can be considered as a distinct construct from that of adaptive coping.

  19. Local environment effects in disordered alloys

    International Nuclear Information System (INIS)

    Cable, J.W.

    1978-01-01

    The magnetic moment of an atom in a ferromagnetic disordered alloy depends on the local environment of that atom. This is particularly true for Ni and Pd based alloys for which neutron diffuse scattering measurements of the range and magnitude of the moment disturbances indicate that both magnetic and chemical environment are important in determining the moment distribution. In this paper we review recent neutron studies of local environment effects in Ni based alloys. These are discussed in terms of a phenomenological model that allows a separation of the total moment disturbance at a Ni site into its chemical and magnetic components

  20. Large eddy simulation of pollutant gas dispersion with buoyancy ejected from building into an urban street canyon.

    Science.gov (United States)

    Hu, L H; Xu, Y; Zhu, W; Wu, L; Tang, F; Lu, K H

    2011-09-15

    The dispersion of buoyancy driven smoke soot and carbon monoxide (CO) gas, which was ejected out from side building into an urban street canyon with aspect ratio of 1 was investigated by large eddy simulation (LES) under a perpendicular wind flow. Strong buoyancy effect, which has not been revealed before, on such pollution dispersion in the street canyon was studied. The buoyancy release rate was 5 MW. The wind speed concerned ranged from 1 to 7.5m/s. The characteristics of flow pattern, distribution of smoke soot and temperature, CO concentration were revealed by the LES simulation. Dimensionless Froude number (Fr) was firstly introduced here to characterize the pollutant dispersion with buoyancy effect counteracting the wind. It was found that the flow pattern can be well categorized into three regimes. A regular characteristic large vortex was shown for the CO concentration contour when the wind velocity was higher than the critical re-entrainment value. A new formula was theoretically developed to show quantitatively that the critical re-entrainment wind velocities, u(c), for buoyancy source at different floors, were proportional to -1/3 power of the characteristic height. LES simulation results agreed well with theoretical analysis. The critical Froude number was found to be constant of 0.7. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Mixing driven by transient buoyancy flows. I. Kinematics

    Science.gov (United States)

    Duval, W. M. B.; Zhong, H.; Batur, C.

    2018-05-01

    Mixing of two miscible liquids juxtaposed inside a cavity initially separated by a divider, whose buoyancy-driven motion is initiated via impulsive perturbation of divider motion that can generate the Richtmyer-Meshkov instability, is investigated experimentally. The measured Lagrangian history of interface motion that contains the continuum mechanics of mixing shows self-similar nearly Gaussian length stretch distribution for a wide range of control parameters encompassing an approximate Hele-Shaw cell to a three-dimensional cavity. Because of the initial configuration of the interface which is parallel to the gravitational field, we show that at critical initial potential energy mixing occurs through the stretching of the interface, which shows frontogenesis, and folding, owing to an overturning motion that results in unstable density stratification and produces an ideal condition for the growth of the single wavelength Rayleigh-Taylor instability. The initial perturbation of the interface and flow field generates the Kelvin-Helmholtz instability and causes kinks at the interface, which grow into deep fingers during overturning motion and unfold into local whorl structures that merge and self-organize into the Rayleigh-Taylor morphology (RTM) structure. For a range of parametric space that yields two-dimensional flows, the unfolding of the instability through a supercritical bifurcation yields an asymmetric pairwise structure exhibiting smooth RTM that transitions to RTM fronts with fractal structures that contain small length scales for increasing Peclet numbers. The late stage of the RTM structure unfolds into an internal breakwave that breaks down through wall and internal collision and sets up the condition for self-induced sloshing that decays exponentially as the two fluids become stably stratified with a diffusive region indicating local molecular diffusion.

  2. Natural ventilation of buildings: opposing wind and buoyancy

    Science.gov (United States)

    Linden, Paul; Hunt, Gary

    1998-11-01

    The use of natural ventilation in buildings is an attractive way to reduce energy usage thereby reducing costs and CO2 emissions. Generally, it is necessary to remove excess heat from a building and the designer can use the buoyancy forces associated with the above ambient temperatures within the building to drive a flow - 'stack' ventilation. The most efficient mode is displacement ventilation where warm air accumulates near the top of the building and flows out through upper level vents and cooler air flows in at lower levels. Ventilation will also be driven between these lower and upper openings by the wind. We report on laboratory modeling and theory which investigates the effects of an opposing wind on stack ventilation driven by a constant source of heat within a space under displacement ventilation. We show that there is a critical wind speed, expressed in dimensionless terms as a critical Froude number, above which displacement ventilation is replaced by (less efficient) mixing ventilation with reversed flow. Below this critical speed, displacement ventilation, in which the interior has a two-layer stratification, is maintained. The criterion for the change in ventilation mode is derived from general considerations of mixing efficiencies in stratified flows. We conclude that even when wind effects might appear to be dominant, the inhibition of mixing by the stable stratification within the space ensures that stack ventilation can operate over a wide range of apparently adverse conditions.

  3. Relativistic effects in local inertial frames including PPN effects

    International Nuclear Information System (INIS)

    Shahid-Saless, B.

    1986-01-01

    In this dissertation they use the concept of a generalized Fermi frame to describe the relativistic effects on a body placed in a local inertial frame of reference due to local and distant sources of gravitation. They have considered, in particular, a model, consisted of two spherically symmetric gravitating sources, moving in circular orbits around a common barycenter where one of the bodies is chosen to be the local and the other the distant one. This has been done in the Parametrized-Post-Newtonian formalism using the slow motion, weak field approximation. The PPN parameters used are γ, β, zeta 1 and zeta 2 . They show that the main relativistic effect on a local satellite is described by the Schwarzchild field of the local body and the nonlinear term corresponding to the self-interaction of the local source itself. There are also much smaller terms that are proportional to the product of the potentials of local and distant bodies and distant body's self interactions. The spatial axis of the local frame undergoes Geodetic precession. Effects involving the parameters zeta 1 and zeta 2 seem to be slightly too small to be observable at the present time. In addition they have found accelerations that vanish in the general relativity limit

  4. Beyond local effective material properties for metamaterials

    Science.gov (United States)

    Mnasri, K.; Khrabustovskyi, A.; Stohrer, C.; Plum, M.; Rockstuhl, C.

    2018-02-01

    To discuss the properties of metamaterials on physical grounds and to consider them in applications, effective material parameters are usually introduced and assigned to a given metamaterial. In most cases, only weak spatial dispersion is considered. It allows to assign local material properties, e.g., a permittivity and a permeability. However, this turned out to be insufficient. To solve this problem, we study here the effective properties of metamaterials with constitutive relations beyond a local response and take strong spatial dispersion into account. This research requires two contributions. First, bulk properties in terms of eigenmodes need to be studied. We particularly investigate the isofrequency surfaces of their dispersion relation are investigated and compared to those of an actual metamaterial. The significant improvement to effectively describe it provides evidence for the necessity to use nonlocal material laws in the effective description of metamaterials. Second, to be able to capitalize on such constitutive relations, also interface conditions need to be known. They are derived in this contribution for our form of the nonlocality using a generalized (weak) formulation of Maxwell's equations. Based on such interface conditions, Fresnel expressions are obtained that predict the amplitude of the reflected and transmitted plane wave upon illuminating a slab of such a nonlocal metamaterial. This all together offers the necessary means for the in-depth analysis of metamaterials characterized by strong spatial dispersion. The general formulation we choose here renders our approach applicable to a wide class of metamaterials.

  5. Numerical modeling of buoyancy-driven turbulent flows in enclosures

    International Nuclear Information System (INIS)

    Hsieh, K.J.; Lien, F.S.

    2004-01-01

    Modeling turbulent natural convection in enclosures with differentially heated vertical walls is numerically challenging, in particular, when low-Reynolds-number (low-Re) models are adopted. When the turbulence level in the core region of cavity is low, most low-Re models, particular those showing good performance for bypass transitional flows, tend to relaminarize the flow and, as a consequence, significantly underpredict the near-wall turbulence intensities and boundary-layer thickness. Another challenge associated with low-turbulence buoyancy-driven flows in enclosures is its inherent unsteadiness, which can pose convergence problems when a steady Reynolds-averaged Navier-Stokes (RANS) equation is solved. In the present study, an unsteady RANS approach in conjunction with the low-Re k-ε model of Lien and Leschziner [Int. J. Comput. Fluid Dyn. 12 (1999) 1] is initially adopted and the predicted flow field is found effectively relaminarized. To overcome this difficulty, likely caused by the low-Re functions in the ε-equation, the two-layer approach is attempted, in which ε is prescribed algebraically using the one-equation k-l model of Wolfshtein [Int. J. Heat Mass Transfer 12 (1969) 301]. The two-layer approach combined with a quadratic stress-strain relation gives overall the best performance in terms of mean velocities, temperature and turbulence quantities

  6. Buoyancy Limitation of Filamentous Cyanobacteria under Prolonged Pressure due to the Gas Vesicles Collapse.

    Science.gov (United States)

    Abeynayaka, Helayaye Damitha Lakmali; Asaeda, Takashi; Kaneko, Yasuko

    2017-08-01

    Freshwater cyanobacterium Pseudanabaena galeata were cultured in chambers under artificially generated pressures, which correspond to the hydrostatic pressures at deep water. Variations occurred in gas vesicles volume, and buoyancy state of cells under those conditions were analyzed at different time intervals (5 min, 1 day, and 5 days). Variations in gas vesicles morphology of cells were observed by transmission electron microscopy images. Settling velocity (Vs) of cells which governs the buoyancy was observed with the aid of a modified optical microscope. Moreover, effects of the prolonged pressure on cell ballast composition (protein and polysaccharides) were examined. Elevated pressure conditions reduced the cell ballast and caused a complete disappearance of gas vesicles in Pseudanabaena galeata cells. Hence cyanobacteria cells were not able to float within the study period. Observations and findings of the study indicate the potential application of hydrostatic pressure, which naturally occurred in hypolimnion of lakes, to inhibit the re-suspension of cyanobacteria cells.

  7. Prominence Bubbles and Plumes: Thermo-magnetic Buoyancy in Coronal Cavity Systems

    Science.gov (United States)

    Berger, Thomas; Hurlburt, N.

    2009-05-01

    The Hinode/Solar Optical Telescope continues to produce high spatial and temporal resolution images of solar prominences in both the Ca II 396.8 nm H-line and the H-alpha 656.3 nm line. Time series of these images show that many quiescent prominences produce large scale (50 Mm) dark "bubbles" that "inflate" into, and sometimes burst through, the prominence material. In addition, small-scale (2--5 Mm) dark plumes are seen rising into many quiescent prominences. We show typical examples of both phenomena and argue that they originate from the same mechanism: concentrated and heated magnetic flux that rises due to thermal and magnetic buoyancy to equilibrium heights in the prominence/coronal-cavity system. More generally, these bubbles and upflows offer a source of both magnetic flux and mass to the overlying coronal cavity, supporting B.C. Low's theory of CME initiation via steadily increasing magnetic buoyancy breaking through the overlying helmut streamer tension forces. Quiescent prominences are thus seen as the lowermost parts of the larger coronal cavity system, revealing through thermal effects both the cooled downflowing "drainage" from the cavity and the heated upflowing magnetic "plasmoids" supplying the cavity. We compare SOT movies to new 3D compressible MHD simulations that reproduce the dark turbulent plume dynamics to establish the magnetic and thermal character of these buoyancy-driven flows into the corona.

  8. Influence of various aspects of low Reynolds number k-ε turbulence models on predicting in-tube buoyancy affected heat transfer to supercritical pressure fluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chen-Ru; Zhang, Zhen [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Jiang, Pei-Xue, E-mail: jiangpx@tsinghua.edu.cn [Beijing Key Laboratory of CO_2 Utilization and Reduction Technology/Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Bo, Han-Liang [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China)

    2017-03-15

    Highlights: • Understanding of the mechanism of buoyancy effect on supercritical heat transfer. • Turbulence related parameters in upward and downward flows were compared. • Turbulent Prandtl number affected the prediction insignificantly. • Buoyancy production was insignificant compared with shear production. • Damping function had the greatest effect and is a priority for further modification. - Abstract: Heat transfer to supercritical pressure fluids was modeled for normal and buoyancy affected conditions using several low Reynolds number k-ε models, including the Launder and Sharma, Myong and Kasagi, and Abe, Kondoh and Nagano, with the predictions compared with experimental data. All three turbulence models accurately predicted the cases without heat transfer deterioration, but failed to accurately predict the cases with heat transfer deterioration although the general trends were captured, indicating that further improvements and modifications are needed for the low Reynolds number k-ε turbulence models to better predict buoyancy deteriorated heat transfer. Further investigations studied the influence of various aspects of the low Reynolds number k-ε turbulence models, including the turbulent Prandtl number, the buoyancy production of turbulent kinetic energy, and the damping function to provide guidelines for model development to more precisely predict buoyancy affected heat transfer. The results show that the turbulent Prandtl number and the buoyancy production of turbulent kinetic energy have little influence on the predictions for cases in this study, while new damping functions with carefully selected control parameters are needed in the low Reynolds number k-ε turbulence models to correctly predict the buoyancy effect for heat transfer simulations in various applications such as supercritical pressure steam generators (SPSGs) in the high temperature gas cooled reactor (HTR) and the supercritical pressure water reactor (SCWR).

  9. Influence of various aspects of low Reynolds number k-ε turbulence models on predicting in-tube buoyancy affected heat transfer to supercritical pressure fluids

    International Nuclear Information System (INIS)

    Zhao, Chen-Ru; Zhang, Zhen; Jiang, Pei-Xue; Bo, Han-Liang

    2017-01-01

    Highlights: • Understanding of the mechanism of buoyancy effect on supercritical heat transfer. • Turbulence related parameters in upward and downward flows were compared. • Turbulent Prandtl number affected the prediction insignificantly. • Buoyancy production was insignificant compared with shear production. • Damping function had the greatest effect and is a priority for further modification. - Abstract: Heat transfer to supercritical pressure fluids was modeled for normal and buoyancy affected conditions using several low Reynolds number k-ε models, including the Launder and Sharma, Myong and Kasagi, and Abe, Kondoh and Nagano, with the predictions compared with experimental data. All three turbulence models accurately predicted the cases without heat transfer deterioration, but failed to accurately predict the cases with heat transfer deterioration although the general trends were captured, indicating that further improvements and modifications are needed for the low Reynolds number k-ε turbulence models to better predict buoyancy deteriorated heat transfer. Further investigations studied the influence of various aspects of the low Reynolds number k-ε turbulence models, including the turbulent Prandtl number, the buoyancy production of turbulent kinetic energy, and the damping function to provide guidelines for model development to more precisely predict buoyancy affected heat transfer. The results show that the turbulent Prandtl number and the buoyancy production of turbulent kinetic energy have little influence on the predictions for cases in this study, while new damping functions with carefully selected control parameters are needed in the low Reynolds number k-ε turbulence models to correctly predict the buoyancy effect for heat transfer simulations in various applications such as supercritical pressure steam generators (SPSGs) in the high temperature gas cooled reactor (HTR) and the supercritical pressure water reactor (SCWR).

  10. Optimal design and control of buoyancy-driven ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2016-01-01

    Relationships between airflow rates and opening areas of importance for design and control are analysed for buoyancy-driven ventilation in a room with two openings and uniform temperature. The optimal ratio between the inlet and outlet areas is found. The consequences of deviations from the optimum...

  11. Buoyancy disorders in pet axolotls Ambystoma mexicanum: three cases.

    Science.gov (United States)

    Takami, Yoshinori; Une, Yumi

    2018-01-31

    As far as we are aware, there are no previous reports on the pathologic conditions of buoyancy disorders in Ambystoma mexicanum. Herein, we describe various clinical test results, clinical outcomes, and the pathological findings of an experimental pneumonectomy procedure in 3 A. mexicanum exhibiting abnormal buoyancy. The 3 pet A. mexicanum were adults, and their respective ages and body weights were 1, 5, and 6 yr and 48, 55, and 56 g. Two of these cases were confirmed via radiographic examination to have free air within the body cavity, and all 3 cases were found via ultrasonography to have an acoustic shadow within the body cavity and were diagnosed with pneumocoelom. Lung perforations were detected macroscopically in 2 of the cases, and all 3 cases had fibrosis in the caudal ends of the lungs. Removal of the lung lesions eliminated the abnormal buoyancy in all 3 cases. We concluded that air had leaked into the body cavity from the lungs, and we propose that lung lesions are an important cause of buoyancy disorders in A. mexicanum.

  12. Use of an Arduino to Study Buoyancy Force

    Science.gov (United States)

    Espindola, P. R.; Cena, C. R.; Alves, D. C. B.; Bozano, D. F.; Goncalves, A. M. B.

    2018-01-01

    The study of buoyancy becomes very interesting when we measure the apparent weight of the body and the liquid vessel weight. In this paper, we propose an experimental apparatus that measures both the forces mentioned before as a function of the depth that a cylinder is sunk into the water. It is done using two load cells connected to an Arduino.…

  13. EVA Development and Verification Testing at NASA's Neutral Buoyancy Laboratory

    Science.gov (United States)

    Jairala, Juniper C.; Durkin, Robert; Marak, Ralph J.; Sipila, Stepahnie A.; Ney, Zane A.; Parazynski, Scott E.; Thomason, Arthur H.

    2012-01-01

    As an early step in the preparation for future Extravehicular Activities (EVAs), astronauts perform neutral buoyancy testing to develop and verify EVA hardware and operations. Neutral buoyancy demonstrations at NASA Johnson Space Center's Sonny Carter Training Facility to date have primarily evaluated assembly and maintenance tasks associated with several elements of the International Space Station (ISS). With the retirement of the Shuttle, completion of ISS assembly, and introduction of commercial players for human transportation to space, evaluations at the Neutral Buoyancy Laboratory (NBL) will take on a new focus. Test objectives are selected for their criticality, lack of previous testing, or design changes that justify retesting. Assembly tasks investigated are performed using procedures developed by the flight hardware providers and the Mission Operations Directorate (MOD). Orbital Replacement Unit (ORU) maintenance tasks are performed using a more systematic set of procedures, EVA Concept of Operations for the International Space Station (JSC-33408), also developed by the MOD. This paper describes the requirements and process for performing a neutral buoyancy test, including typical hardware and support equipment requirements, personnel and administrative resource requirements, examples of ISS systems and operations that are evaluated, and typical operational objectives that are evaluated.

  14. Big infrastructures effects on local developments

    Directory of Open Access Journals (Sweden)

    Bruna Vendemmia

    2011-10-01

    articulation and of translation between different extensive layers of the multi-scaled urban ‘cake’“ (Read, 2007 it will not be astonishing to discover, in Naples Metropolitan Area, new peripheral commercial centralities on the trucks of an old roman street. This synergy, raised in some urban nodes, is the result of a slow bottom-up process. Meanwhile, as the opposite top-down development, and as a consequence of the industrial sector reorganization, faster global dynamics create “new centralities” producing effects at the local scale and increasing the fragmentation. Moreover, it must be taken into account that these layers and processes are not only restricted to physical networks but they are shaped also by economical and social interactions, and that a network is always global and local in all its points (Latour, Nous n'avons jamais été modernes. Essai d'anthropologie symétrique, 1991.From a methodological point of you, a first interpretation of the city growth has driven to the compilation of thematic maps and photographical reports. The information, learned through the graphical and photographical process, were supported by a theoretical approach about both urban development in general and Naples growth in particular. 

  15. Gravitaxis of Euglena gracilis depends only partially on passive buoyancy

    Science.gov (United States)

    Richter, Peter R.; Schuster, Martin; Lebert, Michael; Streb, Christine; Häder, Donat-Peter

    In darkness, the unicellular freshwater flagellate Euglena gracilis shows a pronounced negative gravitactic behavior, and the cells swim actively upward in the water column. Up to now it was unclear whether this behavior is based on a passive (physical) alignment mechanism (e.g., buoyancy due to a fore-aft asymmetry of the cell body) or on an active physiological mechanism. A sounding rocket experiment was performed in which the effect of sub-1g-accelerations (0.05, 0.08, 0.12, and 0.2g) on untreated living cells and immobilized (fixation with liquid nitrogen) cells was observed. By means of computerized image analysis the angles of the cells long axis with respect to the acceleration vector were analyzed in order to calculate and compare the reorientation kinetics of the immobilized cells versus that of the controls. In both groups, the reorientation kinetics depended on the dose, but the reorientation of the living cells was about five times faster than that of the immobilized cells. This indicates that in young cells gravitaxis can be explained by a physical mechanism only to a small extend. In older cultures, in which the cells often have a drop shaped cell body, the physical reorientation is considerably faster, and a more pronounced influence of passive alignment caused by fore/aft asymmetry (drag-gravity model) can not be excluded. In addition to these results, Euglena gracilis cells seem to respond very sensitively to small accelerations when they are applied after a longer microgravity period. The data indicate that gravitactic orientation occurred at an acceleration as low as 0.05g.

  16. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced as...

  17. Non-Local Effects in Kaonic Atoms

    International Nuclear Information System (INIS)

    Lutz, M.; Florkowski, W.

    2000-01-01

    Optical potentials with non-local (gradient) terms are used to describe the spectra of kaonic atoms. The strength of the non-local terms is determined from a many-body calculation of the kaon self energy in nuclear matter. We find that the non-local terms are quantitatively important and the results depend strongly on the way the gradient terms are arranged. Phenomenologically successful description is obtained for p-wave like optical potentials. It is suggested that the microscopic form of the non-local interaction terms is obtained systematically by means of a semi-classical expansion of the nucleus structure. (author)

  18. Non-local effects in kaonic atoms

    International Nuclear Information System (INIS)

    Lutz, M.; Florkowski, W.

    2000-04-01

    Optical potentials with non-local (gradient) terms are used to describe the spectra of kaonic atoms. The strength of the non-local terms is determined from a many-body calculation of the kaon self-energy in nuclear matter. The optical potentials show strong non-linearities in the nucleon density and sizeable non-local terms. We find that the non-local terms are quantitatively important and the results depend strongly on the way the gradient terms are arranged. Phenomenologically successful fits are obtained for p-wave like optical potentials. It is suggested that the microscopic form of the non-local interaction terms is obtained systematically by means of a semi-classical expansion of the nucleus structure. We conclude that a microscopic description of kaonic atom data requires further detailed studies of the microscopic K - nuclear dynamics. (orig.)

  19. Experimental aspects of buoyancy correction in measuring reliable high-pressure excess adsorption isotherms using the gravimetric method

    Science.gov (United States)

    Nguyen, Huong Giang T.; Horn, Jarod C.; Thommes, Matthias; van Zee, Roger D.; Espinal, Laura

    2017-12-01

    Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO2 and supercritical N2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

  20. Manipulating Microrobots Using Balanced Magnetic and Buoyancy Forces

    Directory of Open Access Journals (Sweden)

    Lin Feng

    2018-01-01

    Full Text Available We present a novel method for the three-dimensional (3D control of microrobots within a microfluidic chip. The microrobot body contains a hollow space, producing buoyancy that allows it to float in a microfluidic environment. The robot moves in the z direction by balancing magnetic and buoyancy forces. In coordination with the motion of stages in the xy plane, we achieved 3D microrobot control. A microgripper designed to grasp micron-scale objects was attached to the front of the robot, allowing it to hold and deliver micro-objects in three dimensions. The microrobot had four degrees of freedom and generated micronewton-order forces. We demonstrate the microrobot’s utility in an experiment in which it grips a 200 μm particle and delivers it in a 3D space.

  1. Buoyancy suppression in gases at high temperatures

    International Nuclear Information System (INIS)

    Kuczmarski, Maria A.; Gokoglu, Suleyman A.

    2007-01-01

    The computational fluid dynamics code FLUENT was used to study Rayleigh instability at large temperature differences in a sealed gas-filled enclosure with a cold top wall and a heated bottom wall (Benard problem). Both steady state and transient calculations were performed. Instability boundaries depending on the geometry, temperature, and pressure were defined that showed the system tended to become more unstable when the hot-wall temperature increased beyond a certain level, a result of the dampening effect of gas viscosity at higher temperatures. Results also showed that the eventual system stability depended on the final pressure reached at steady state, regardless of how fast the bottom-wall temperature was ramped up to minimize time spent in the unstable region of fluid motion. It was shown that the final system state can differ depending on whether results are obtained via a steady-state or transient calculation, demonstrating that the history of the flow structure development and corresponding temperature fields in this type of system has a profound effect on the final state. Finally, changes in the slope of the pressure-versus-time curve were found to be good indicators of flow pattern changes, and can be a convenient experimental tool for diagnosing the expected changes in flow behavior in such systems

  2. A Review of Some Recent Studies on Buoyancy Driven Flows in an Urban Environment

    OpenAIRE

    Bodhisatta Hajra

    2014-01-01

    This paper reviews some recent studies (after 2000) pertaining to buoyancy driven flows in nature and thier use in reducing air pollution levels in a city (city ventilation). Natural convection flows occur due to the heating and cooling of various urban surfaces (e.g., mountain slopes), leading to upslope and downslope flows. Such flows can have a significant effect on city ventilation which has been the subject of study in the recent times due to increased pollution levels in a city. A major...

  3. Relative-locality effects in Snyder spacetime

    International Nuclear Information System (INIS)

    Mignemi, S.; Samsarov, A.

    2017-01-01

    Most models of noncommutative geometry and doubly special relativity suggest that the principle of absolute locality should be replaced by the milder notion of relative locality. In particular, they predict the occurrence of a delay in the time of arrival of massless particle of different energies emitted by a distant observer. In this letter, we show that this is not the case with Snyder spacetime, essentially because the Lorentz invariance is not deformed in this case. Distant observers may however measure different times of flight for massive particles. - Highlights: • We discuss the dynamics of the Snyder model from the point of view of relative locality. • We show that no time delay is present for particles emitted by distant observers. • We ascribe this fact to the Lorentz invariance of the model. • Distant observers may however measure different times of flight for massive particle.

  4. Relative-locality effects in Snyder spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Samsarov, A., E-mail: andjelo.samsarov@irb.hr [Rudjer Bošković Institute, Bijenička cesta 54, 10002 Zagreb (Croatia)

    2017-05-18

    Most models of noncommutative geometry and doubly special relativity suggest that the principle of absolute locality should be replaced by the milder notion of relative locality. In particular, they predict the occurrence of a delay in the time of arrival of massless particle of different energies emitted by a distant observer. In this letter, we show that this is not the case with Snyder spacetime, essentially because the Lorentz invariance is not deformed in this case. Distant observers may however measure different times of flight for massive particles. - Highlights: • We discuss the dynamics of the Snyder model from the point of view of relative locality. • We show that no time delay is present for particles emitted by distant observers. • We ascribe this fact to the Lorentz invariance of the model. • Distant observers may however measure different times of flight for massive particle.

  5. On buoyancy-driven natural ventilation of a room with a heated floor

    Science.gov (United States)

    Gladstone, Charlotte; Woods, Andrew W.

    2001-08-01

    The natural ventilation of a room, both with a heated floor and connected to a cold exterior through two openings, is investigated by combining quantitative models with analogue laboratory experiments. The heated floor generates an areal source of buoyancy while the openings allow displacement ventilation to operate. When combined, these produce a steady state in which the air in the room is well-mixed, and the heat provided by the floor equals the heat lost by displacement. We develop a quantitative model describing this process, in which the advective heat transfer through the openings is balanced with the heat flux supplied at the floor. This model is successfully tested with observations from small-scale analogue laboratory experiments. We compare our results with the steady-state flow associated with a point source of buoyancy: for a given applied heat flux, an areal source produces heated air of lower temperature but a greater volume flux of air circulates through the room. We generalize the model to account for the effects of (i) a cooled roof as well as a heated floor, and (ii) an external wind or temperature gradient. In the former case, the direction of the flow through the openings depends on the temperature of the exterior air relative to an averaged roof and floor temperature. In the latter case, the flow is either buoyancy dominated or wind dominated depending on the strength of the pressure associated with the wind. Furthermore, there is an intermediate multiple-solution regime in which either flow regime may develop.

  6. Nociceptive Effects of Locally Treated Metoprolol

    Directory of Open Access Journals (Sweden)

    Nursima Cukadar

    2015-06-01

    Results: Metoprolol, an antagonist, significantly decreased the thermal latency and mechanical thresholds with dose and time dependent manner. However, dobutamine, an agonist, enhanced the latency and thresholds dose and time dependent. Conclusions: This results suggest that in contrast to dobutamine, locally treated metoprolol may cause hyperalgesic and allodynic actions. In addition, our results can demonstrate that peripheral beta-adrenergic receptors can play important roles in nociceptive process. [Cukurova Med J 2015; 40(2.000: 258-266

  7. A continuous and prognostic convection scheme based on buoyancy, PCMT

    Science.gov (United States)

    Guérémy, Jean-François; Piriou, Jean-Marcel

    2016-04-01

    A new and consistent convection scheme (PCMT: Prognostic Condensates Microphysics and Transport), providing a continuous and prognostic treatment of this atmospheric process, is described. The main concept ensuring the consistency of the whole system is the buoyancy, key element of any vertical motion. The buoyancy constitutes the forcing term of the convective vertical velocity, which is then used to define the triggering condition, the mass flux, and the rates of entrainment-detrainment. The buoyancy is also used in its vertically integrated form (CAPE) to determine the closure condition. The continuous treatment of convection, from dry thermals to deep precipitating convection, is achieved with the help of a continuous formulation of the entrainment-detrainment rates (depending on the convective vertical velocity) and of the CAPE relaxation time (depending on the convective over-turning time). The convective tendencies are directly expressed in terms of condensation and transport. Finally, the convective vertical velocity and condensates are fully prognostic, the latter being treated using the same microphysics scheme as for the resolved condensates but considering the convective environment. A Single Column Model (SCM) validation of this scheme is shown, allowing detailed comparisons with observed and explicitly simulated data. Four cases covering the convective spectrum are considered: over ocean, sensitivity to environmental moisture (S. Derbyshire) non precipitating shallow convection to deep precipitating convection, trade wind shallow convection (BOMEX) and strato-cumulus (FIRE), together with an entire continental diurnal cycle of convection (ARM). The emphasis is put on the characteristics of the scheme which enable a continuous treatment of convection. Then, a 3D LAM validation is presented considering an AMMA case with both observations and a CRM simulation using the same initial and lateral conditions as for the parameterized one. Finally, global

  8. Effect of coulomb interaction on Anderson localization

    International Nuclear Information System (INIS)

    Waintal, X.

    1999-01-01

    We study the quantum mechanics of interacting particles in a disordered system, and in particular, what happens to Anderson localisation when interaction is taken into account. In the first part, one looks at the excited states of two particles in one dimension. For this model, it has been shown (Shepelyansky 1994) that a local repulsive interaction can partially destroy Anderson localisation. Here, we show that this model has similarities with the three-dimensional Anderson model at the metal-insulator transition. In particular, the maximum of rigidity obtained in the spectral statistics correspond to some intermediary statistics that cannot be described by random matrix theory neither by a Poisson statistics. The wave functions show a multifractal behaviour and the spreading of the center of mass of a wave packet is logarithmic in time. The second part deals with the ground state of a finite density of spinless fermions in two dimensions. After the scaling theory of localisation, it was commonly accepted that there was no metal in two dimensions. This idea has been challenged by the observation of a metal-insulator transition in low density electron gas (Kravchenko et al. 1994). We propose a scenario in which a metallic phase occurs between the Anderson insulator and the pinned Wigner crystal. This intermediate phase is characterized by an alignment of the local currents flowing in the system. (author)

  9. Experimental study of buoyancy driven natural ventilation through horizontal openings

    OpenAIRE

    Heiselberg, Per; Li, Zhigang

    2007-01-01

    An experimental study of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. Measurements were made for opening ratios L/D range from 0.027 to 4.455, where L and D are the length and the diameter of the opening, respectively. The bidirectional air flow rate was measured using constant injection tracer gas technique. Smoke visualizations showed that the air flow patterns are highly transient, unstable and complex, and ...

  10. Use of an Arduino to study buoyancy force

    Science.gov (United States)

    Espindola, P. R.; Cena, C. R.; Alves, D. C. B.; Bozano, D. F.; Goncalves, A. M. B.

    2018-05-01

    The study of buoyancy becomes very interesting when we measure the apparent weight of the body and the liquid vessel weight. In this paper, we propose an experimental apparatus that measures both the forces mentioned before as a function of the depth that a cylinder is sunk into the water. It is done using two load cells connected to an Arduino. With this experiment, the student can verify Archimedes’ principle, Newton’s third law, and calculate the density of a liquid. This apparatus can be used in fluid physics laboratories as a substitute for very expensive sensor kits or even to improve too simple approaches, usually employed, but still at low cost.

  11. Modeling the Buoyancy System of a Wave Energy Power Plant

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Nielsen, Kirsten M.

    2009-01-01

    A nonlinear dynamic model of the buoyancy system in a wave energy power plant is presented. The plant ("Wave Dragon") is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the WD, and hydro turbines lead the water to the sea...... producing electrical power. Through air chambers it is possible to control the level of the WD. It is important to control the level in order to maximize the power production in proportion to the wave height, here the amount of overtopping water and the amount of potential energy is conflicting...

  12. Experimental study of buoyancy driven natural ventilation through horizontal openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2007-01-01

    An experimental study of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. Measurements were made for opening ratios L/D range from 0.027 to 4.455, where L and D are the length and the diameter of the opening......, respectively. The bidirectional air flow rate was measured using constant injection tracer gas technique. Smoke visualizations showed that the air flow patterns are highly transient, unstable and complex, and that air flow rates oscillate with time. Correlations between the Froude number Fr and the L/D ratio...

  13. Buoyed by geophysics : geophysics, just-in-time procurement help save millions on Ekwan pipeline buoyancy control

    Energy Technology Data Exchange (ETDEWEB)

    Roche, P.

    2005-09-01

    million. AMEC also opted for the use of screw anchors and deep ditches, both equally effective buoyancy control measures. Once pipeline construction was underway, test pits were dug to further investigate ground conditions. AMEC negotiated to buy only a portion of the required bolt-on weights when construction began, and ordered more as needed during construction. Buoyancy control on the Ekwan pipeline project was reduced from $9 million to less than $2 million. 4 figs.

  14. Simulation of buoyancy-induced turbulent flow from a hot horizontal jet

    KAUST Repository

    El-Amin, Mohamed

    2014-02-01

    Experimental visualizations and numerical simulations of a horizontal hot water jet entering cold water into a rectangular storage tank are described. Three different temperature differences and their corresponding Reynolds numbers are considered. Both experimental visualization and numerical computations are carried out for the same flow and thermal conditions. The realizable k - ε model is used for modeling the turbulent flow while the buoyancy is modeled using the Boussinesq approximation. Polynomial approximations of the water properties are used to compare with the Boussinesq approximation. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank as well as the Froude number are analyzed. The experimental visualizations are performed at intervals of five seconds for all different cases. The simulated results are compared with the visualized results, and both of them show the stratification phenomena and buoyancy force effects due to temperature difference and density variation. After certain times, depending on the case condition, the flow tends to reach a steady state. © 2014 Publishing House for Journal of Hydrodynamics.

  15. Buoyancy of gas-filled bladders at great depth

    Science.gov (United States)

    Priede, Imants G.

    2018-02-01

    At high hydrostatic pressures exceeding 20 MPa or 200 bar, equivalent to depths exceeding ca.2000 m, the behaviour of gases deviates significantly from the predictions of standard equations such as Boyle's Law, the Ideal Gas Law and Van der Waals equation. The predictions of these equations are compared with experimental data for nitrogen, oxygen and air at 0 °C and 15 °C, at pressures up to 1100 bar (110 MPa) equivalent to full ocean depth of ca. 11000 m. Owing to reduced compressibility of gases at high pressures, gas-filled bladders at full ocean depth have a density of 847 kg m-3 for Oxygen, 622 kg m-3 for Nitrogen and 660 kg m-3 for air providing potentially useful buoyancy comparable with that available from man-made materials. This helps explain why some of the deepest-living fishes at ca. 7000 m depth (700 bar or 70 MPa) have gas-filled swim bladders. A table is provided of the density and buoyancy of oxygen, nitrogen and air at 0 °C and 15 °C from 100 to 1100 bar.

  16. Response of mantle transition zone thickness to plume buoyancy flux

    Science.gov (United States)

    Das Sharma, S.; Ramesh, D. S.; Li, X.; Yuan, X.; Sreenivas, B.; Kind, R.

    2010-01-01

    The debate concerning thermal plumes in the Earth's mantle, their geophysical detection and depth characterization remains contentious. Available geophysical, petrological and geochemical evidence is at variance regarding the very existence of mantle plumes. Utilizing P-to-S converted seismic waves (P receiver functions) from the 410 and 660 km discontinuities, we investigate disposition of these boundaries beneath a number of prominent hotspot regions. The thickness of the mantle transition zone (MTZ), measured as P660s-P410s differential times (tMTZ), is determined. Our analyses suggest that the MTZ thickness beneath some hotspots correlates with the plume strength. The relationship between tMTZ, in response to the thermal perturbation, and the strength of plumes, as buoyancy flux B, follows a power law. This B-tMTZ behavior provides unprecedented insights into the relation of buoyancy flux and excess temperature at 410-660 km depth below hotspots. We find that the strongest hotspots, which are located in the Pacific, are indeed plumes originating at the MTZ or deeper. According to the detected power law, even the strongest plumes may not shrink the transition zone by significantly more than ~40 km (corresponding to a maximum of 300-400° excess temperature).

  17. To an effective local Langlands correspondence

    CERN Document Server

    Bushnell, Colin J

    2014-01-01

    Let F be a non-Archimedean local field. Let \\mathcal{W}_{F} be the Weil group of F and \\mathcal{P}_{F} the wild inertia subgroup of \\mathcal{W}_{F}. Let \\widehat {\\mathcal{W}}_{F} be the set of equivalence classes of irreducible smooth representations of \\mathcal{W}_{F}. Let \\mathcal{A}^{0}_{n}(F) denote the set of equivalence classes of irreducible cuspidal representations of \\mathrm{GL}_{n}(F) and set \\widehat {\\mathrm{GL}}_{F} = \\bigcup _{n\\ge 1} \\mathcal{A}^{0}_{n}(F). If \\sigma \\in \\widehat {\\mathcal{W}}_{F}, let ^{L}{\\sigma }\\in \\widehat {\\mathrm{GL}}_{F} be the cuspidal representation matched with \\sigma by the Langlands Correspondence. If \\sigma is totally wildly ramified, in that its restriction to \\mathcal{P}_{F} is irreducible, the authors treat ^{L}{\\sigma} as known. From that starting point, the authors construct an explicit bijection \\mathbb{N}:\\widehat {\\mathcal{W}}_{F} \\to \\widehat {\\mathrm{GL}}_{F}, sending \\sigma to ^{N}{\\sigma}. The authors compare this "naïve correspondence" with the L...

  18. A numerical study on buoyancy-driven flow in an inclined square enclosure heated and cooled on adjacent walls

    International Nuclear Information System (INIS)

    Aydin, O.; Uenal, A.; Ayhan, T.

    1999-01-01

    Buoyancy-driven flows in enclosures play a vital role in many engineering applications such as double glazing, ventilation of rooms, nuclear reactor insulation, solar energy collection, cooling of electronic components, and crystal growth in liquids. Here, numerical study on buoyancy-driven laminar flow in an inclined square enclosure heated from one side and cooled from the adjacent side is conducted using finite difference methods. The effect of inclination angle on fluid flow and heat transfer is investigated by varying the angle of inclination between 0 degree and 360degree, and the results are presented in the form of streamlines and isotherms for different inclination angles and Rayleigh numbers. On the basis of the numerical data, the authors determine the critical values of the inclination angle at which the rate of the transfer within the enclosure is either maximum or minimum

  19. Characteristics of buoyancy force on stagnation point flow with magneto-nanoparticles and zero mass flux condition

    Directory of Open Access Journals (Sweden)

    Iftikhar Uddin

    2018-03-01

    Full Text Available This attempt dedicated to the solution of buoyancy effect over a stretching sheet in existence of MHD stagnation point flow with convective boundary conditions. Thermophoresis and Brownian motion aspects are included. Incompressible fluid is electrically conducted in the presence of varying magnetic field. Boundary layer analysis is used to develop the mathematical formulation. Zero mass flux condition is considered at the boundary. Non-linear ordinary differential system of equations is constructed by means of proper transformations. Interval of convergence via numerical data and plots are developed. Characteristics of involved variables on the velocity, temperature and concentration distributions are sketched and discussed. Features of correlated parameters on Cf and Nu are examined by means of tables. It is found that buoyancy ratio and magnetic parameters increase and reduce the velocity field. Further opposite feature is noticed for higher values of thermophoresis and Brownian motion parameters on concentration distribution. Keywords: Stagnation point, MHD, Nanoparticles, Zero mass flux condition

  20. The Thick Market Effect on Local Unemployment Rate Fluctuations

    OpenAIRE

    Li Gan; Qinghua Zhang

    2005-01-01

    This paper studies how the thick market effect influences local unemployment rate fluctuations. The paper presents a model to demonstrate that the average matching quality improves as the number of workers and firms increases. Unemployed workers accumulate in a city until the local labor market reaches a critical minimum size, which leads to cyclical fluctuations in the local unemployment rates. Since larger cities attain the critical market size more frequently, they have shorter unemploymen...

  1. Evidence of Non-local Chemical, Thermal and Gravitational Effects

    Directory of Open Access Journals (Sweden)

    Hu H.

    2007-04-01

    Full Text Available Quantum entanglement is ubiquitous in the microscopic world and manifests itself macroscopically under some circumstances. But common belief is that it alone cannot be used to transmit information nor could it be used to produce macroscopic non- local effects. Yet we have recently found evidence of non-local effects of chemical substances on the brain produced through it. While our reported results are under independent verifications by other groups, we report here our experimental findings of non-local chemical, thermal and gravitational effects in simple physical systems such as reservoirs of water quantum-entangled with water being manipulated in a remote reservoir. With the aids of high-precision instruments, we have found that the pH value, temperature and gravity of water in the detecting reservoirs can be non-locally affected through manipulating water in the remote reservoir. In particular, the pH value changes in the same direction as that being manipulated; the temperature can change against that of local environment; and the gravity apparently can also change against local gravity. These non-local effects are all reproducible and can be used for non-local signalling and many other purposes. We suggest that they are mediated by quantum entanglement between nuclear and/or electron spins in treated water and discuss the implications of these results.

  2. THE EFFECT OF LOCAL ANESTHETICS ON TEAR PRODUCTION

    African Journals Online (AJOL)

    that local anesthetics measure only basic secretion thus reducing normal tear production/secretion, which is both reflex and basic. This could be attributed to the fact that local anesthetics have an adrenergic potentiating effects and because lacrimal fluid receive a preganglionic parasympathetic supply from lacrimal muscles ...

  3. Non-local Effects of Conformal Anomaly

    Science.gov (United States)

    Meissner, Krzysztof A.; Nicolai, Hermann

    2018-03-01

    It is shown that the nonlocal anomalous effective actions corresponding to the quantum breaking of the conformal symmetry can lead to observable modifications of Einstein's equations. The fact that Einstein's general relativity is in perfect agreement with all observations including cosmological or recently observed gravitational waves imposes strong restrictions on the field content of possible extensions of Einstein's theory: all viable theories should have vanishing conformal anomalies. It is shown that a complete cancellation of conformal anomalies in D=4 for both the C^2 invariant and the Euler (Gauss-Bonnet) invariant can only be achieved for N-extended supergravity multiplets with N ≥ 5.

  4. Council Appointed Mayors in Spain: Effects on Local Democracy

    Directory of Open Access Journals (Sweden)

    María Jesús García García

    2017-03-01

    Full Text Available This paper deals with the influence of having council appointed mayors on local governments. Five elements of local government systems are considered: the electoral system and its influence on the political composition of the local government; the local government structure and the distribution of functions and powers between mayor and council; the role of political parties; scrutiny of the executive and accountability; and citizen participation. This analysis highlights the effect that a council appointed mayor system has in terms of accountability and legitimacy, transparency and efficiency. KEYWORDS Local government systems, directly elected mayors, local governance, council appointed mayors, Local Government Structure; Political Parties; Citizen Participation; Accountability. El presente artículo toma en consideración los efectos que el sistema de elección del Alcalde tiene sobre la democracia local, basándose en la consideración cinco aspectos: el sistema electoral y su influencia en la composición política de las administraciones locales; la estructura de la administración local y la distribución de funciones entre los alcaldes y el pleno municipal; el papel de los partidos políticos; los mecanismos de control del ejecutivo local y la participación ciudadana. El estudio subraya especialmente la incidencia que el sistema de elección del alcalde por los concejales tiene en relación con los principios de responsabilidad, legitimidad, transparencia y eficiencia de la gestión local. PALABRAS CLAVE Gobierno local, elección directa de los alcaldes, elección indirecta de los alcaldes, estructura del gobierno local, partidos políticos, participación ciudadana, responsabilidad política.

  5. Positive segregation as a function of buoyancy force during steel ingot solidification

    International Nuclear Information System (INIS)

    Radovic, Zarko; Jaukovic, Nada; Lalovic, Milisav; Tadic, Nebojsa

    2008-01-01

    We analyze theoretically and experimentally solute redistribution in the dendritic solidification process and positive segregation during solidification of steel ingots. Positive segregation is mainly caused by liquid flow in the mushy zone. Changes in the liquid steel velocity are caused by the temperature gradient and by the increase in the solid fraction during solidification. The effects of buoyancy and of the change in the solid fraction on segregation intensity are analyzed. The relationships between the density change, liquid fraction and the steel composition are considered. Such elements as W, Ni, Mo and Cr decrease the effect of the density variations, i.e. they show smaller tendency to segregate. Based on the modeling and experimental results, coefficients are provided controlling the effects of chemical composition, secondary dendrite arm spacing and the solid fraction.

  6. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Z.; Chin, Y.S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  7. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    International Nuclear Information System (INIS)

    Liang, Z.; Chin, Y.S.

    2014-01-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  8. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    Energy Technology Data Exchange (ETDEWEB)

    Hu, L.H., E-mail: hlh@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huo, R.; Yang, D. [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  9. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow.

    Science.gov (United States)

    Hu, L H; Huo, R; Yang, D

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons--a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  10. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    International Nuclear Information System (INIS)

    Hu, L.H.; Huo, R.; Yang, D.

    2009-01-01

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  11. Numerical investigations of buoyancy-driven natural ventilation in a simple three-storey atrium building and thermal comfort evaluation

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2013-01-01

    The numerical investigations of buoyancy-driven natural ventilation and thermal comfort evaluation in a simple three-storey atrium building as a part of the passive ventilation strategy was undertaken using a validated Computational Fluid Dynamic (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modeling approach with the SST-k–ω turbulence model and the discrete transfer radiation model (DTRM) was used for the numerical investigations. The steady-state governing equations were solved using a commercial solver FLUENT©. Various flow situations of the buoyancy-driven natural ventilation in the building during day and night time were examined. The numerical results obtained for the airflow rates, airflow patterns and temperature distributions inside the building are presented in this paper. Using the numerical results, the well-known thermal comfort indices PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for the evaluation of the thermal comfort conditions in the occupied regions of the building. It was noticed that thermal conditions prevailing in the occupied areas of the building as a result of using the buoyancy-driven ventilation were mostly in comfort zone. From the study of the night time ventilation, it was found that hot water (80 °C) circulation (heated by solar collectors during daytime) along the chimney walls during night time and heat sources present in the building can be useful in inducing night ventilation airflows in the building as a part of the passive ventilation strategy. -- Highlights: • A simple three-storey atrium building. • Numerical modeling of buoyancy-driven ventilation flow in the building. • Effect of solar intensity and geographical location on ventilation. • CFD predictions were used to calculate thermal comfort indices. • Evaluation of thermal comfort conditions for the occupants

  12. Characteristics of Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Li, Zhigang

    through horizontal openings. Two cases of full-scale measurements of buoyancy driven natural ventilation through horizontal openings are performed: one horizontal opening and one horizontal opening combined with one vertical opening. For the case of one horizontal opening, the measurements are made....... Computational fluid dynamics (CFD) are used to study these two air flow cases. The air flow rate and air flow pattern are predicted and compared with the full-scale measurements. The measurement data are used to compare two CFD models: standard k- ε model and large eddy simulation (LES) model. The cases...... transient, unstable and complex, and the air flow rates oscillate with time. Correlations between the Froude number Fr and the opening ratio L/D are obtained, which is reasonable agreement with Epstein's formula derived from brine-water measurements, but the obtained Fr values show considerable deviations...

  13. Buoyancy-driven mixing of fluids in a confined geometry

    International Nuclear Information System (INIS)

    Hallez, Y.

    2007-12-01

    The present work based on Direct Numerical Simulations is devoted to the study of mixing between two miscible fluids of different densities. The movement of these fluids is induced by buoyancy. Three geometries are considered: a cylindrical tube, a square channel and a plane two-dimensional flow. For cylindrical tubes, the results of numerical simulations fully confirm previous experimental findings by Seon et al., especially regarding the existence of three different flow regimes, depending on the tilt angle. The comparison of the various geometries shows that tridimensional flows in tubes or channels are similar, whereas the two-dimensional model fails to give reliable information about real 3D flows, either from a quantitative point of view or for a phenomenological understanding. A peculiar attention is put on a joint analysis of the concentration and vorticity fields and allows us to explain several subtle aspects of the mixing dynamics. (author)

  14. Buoyancy differences among two deepwater ciscoes from the Great Lakes and their putative ancestor

    Science.gov (United States)

    Krause, A.E.; Eshenroder, R.L.; Begnoche, L.J.

    2002-01-01

    We analyzed buoyancy in two deepwater ciscoes, Coregonus hoyi and C. kiyi, and in C. artedi, their putative ancestor, and also analyzed how variations in fish weight, water content, and lipid content affected buoyancy. Buoyancy was significantly different among the three species (p < 0.0001). Estimates of percent buoyancy (neutral buoyancy = 0.0%) were: kiyi, 3.8%; hoyi, 4.7%; and artedi, 5.7%. Buoyancy did not change with fish weight alone (p = 0.38). Fish weight was negatively related to water content for all three species (p = 0.037). Lipid content was not significantly different between hoyi and kiyi, but artedi had significantly fewer lipids than hoyi and kiyi (p < 0.10). When artedi was removed from the analysis, fish weight and lipids accounted for 48% of the variation in buoyancy (p = 0.003), fatter hoyi were less dense than leaner hoyi, but fatter and leaner kiyi were no different in density. Our findings provide additional evidence that buoyancy regulation was a speciating mechanism in deepwater ciscoes and that kiyi is more specialized than hoyi for diel-vertical migration in deep water.

  15. Research and development at the Marshall Space Flight Center Neutral Buoyancy Simulator

    Science.gov (United States)

    Kulpa, Vygantas P.

    1987-01-01

    The Neutral Buoyancy Simulator (NBS), a facility designed to imitate zero-gravity conditions, was used to test the Experimental Assembly of Structures in Extravehicular Activity (EASE) and the Assembly Concept for Construction of Erectable Space Structures (ACCESS). Neutral Buoyancy Simulator applications and operations; early space structure research; development of the EASE/ACCESS experiments; and improvement of NBS simulation are summarized.

  16. 40 CFR 1065.690 - Buoyancy correction for PM sample media.

    Science.gov (United States)

    2010-07-01

    ... mass, use a sample media density of 920 kg/m3. (3) For PTFE membrane (film) media with an integral... media. 1065.690 Section 1065.690 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Buoyancy correction for PM sample media. (a) General. Correct PM sample media for their buoyancy in air if...

  17. Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals.

    Science.gov (United States)

    Sato, Katsufumi; Aoki, Kagari; Watanabe, Yuuki Y; Miller, Patrick J O

    2013-01-01

    Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.

  18. Effective Management for National or Local Policy Objectives?

    DEFF Research Database (Denmark)

    Winter, Søren; Skou, Mette; Beer, Frederikke

    This research considers the role of local policies and management in affecting street-level bureaucrats’ actions in implementing national policy mandates. The focus on sanctioning behavior by social workers provides a strong test of these effects, given that the behaviors are both visible and have...... workers with a better fit with the goals of the organization increases workers’ compliance with local policy goals, but only when these diverge from national ones! Increasing staff capacity and information provision have simpler effects in fostering more compliance with the national policy mandate among...... workers. Managers’ addressing adverse selection problems seems more effective than coping with moral hazard. The combination of local politicians’ influence on the formation of local policy goals and managers’ influence in getting workers to comply with those indicates a very important role for policy...

  19. local

    Directory of Open Access Journals (Sweden)

    Abílio Amiguinho

    2005-01-01

    Full Text Available The process of socio-educational territorialisation in rural contexts is the topic of this text. The theme corresponds to a challenge to address it having as main axis of discussion either the problem of social exclusion or that of local development. The reasons to locate the discussion in this last field of analysis are discussed in the first part of the text. Theoretical and political reasons are there articulated because the question is about projects whose intentions and practices call for the political both in the theoretical debate and in the choices that anticipate intervention. From research conducted for several years, I use contributions that aim at discuss and enlighten how school can be a potential locus of local development. Its identification and recognition as local institution (either because of those that work and live in it or because of those that act in the surrounding context are crucial steps to progressively constitute school as a partner for development. The promotion of the local values and roots, the reconstruction of socio-personal and local identities, the production of sociabilities and the equation and solution of shared problems were the dimensions of a socio-educative intervention, markedly globalising. This scenario, as it is argued, was also, intentionally, one of transformation and of deliberate change of school and of the administration of the educative territoires.

  20. Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage

    KAUST Repository

    Allen, Rebecca

    2015-04-01

    ABSTRACT Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage Rebecca Allen Geological CO2 storage is an engineering feat that has been undertaken around the world for more than two decades, thus accurate modeling of flow and transport behavior is of practical importance. Diffusive and convective transport are relevant processes for buoyancy-driven convection of CO2 into underlying fluid, a scenario that has received the attention of numerous modeling studies. While most studies focus on Darcy-scale modeling of this scenario, relatively little work exists at the pore-scale. In this work, properties evaluated at the pore-scale are used to investigate the transport behavior modeled at the Darcy-scale. We compute permeability and two different forms of tortuosity, namely hydraulic and diffusive. By generating various pore ge- ometries, we find hydraulic and diffusive tortuosity can be quantitatively different in the same pore geometry by up to a factor of ten. As such, we emphasize that these tortuosities should not be used interchangeably. We find pore geometries that are characterized by anisotropic permeability can also exhibit anisotropic diffusive tortuosity. This finding has important implications for buoyancy-driven convection modeling; when representing the geological formation with an anisotropic permeabil- ity, it is more realistic to also account for an anisotropic diffusivity. By implementing a non-dimensional model that includes both a vertically and horizontally orientated 5 Rayleigh number, we interpret our findings according to the combined effect of the anisotropy from permeability and diffusive tortuosity. In particular, we observe the Rayleigh ratio may either dampen or enhance the diffusing front, and our simulation data is used to express the time of convective onset as a function of the Rayleigh ratio. Also, we implement a lattice Boltzmann model for thermal convective flows, which we treat as an analog for

  1. Buoyancy driven flow in a hot water tank due to standby heat loss

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon

    2012-01-01

    Results of experimental and numerical investigations of thermal behavior in a vertical cylindrical hot water tank due to standby heat loss of the tank are presented. The effect of standby heat loss on temperature distribution in the tank is investigated experimentally on a slim 150l tank...... show that the CFD model predicts satisfactorily water temperatures at different levels of the tank during cooling by standby heat loss. It is elucidated how the downward buoyancy driven flow along the tank wall is established by the heat loss from the tank sides and how the natural convection flow...... with a height to diameter ratio of 5. A tank with uniform temperatures and with thermal stratification is studied. A detailed computational fluid dynamics (CFD) model of the tank is developed to calculate the natural convection flow in the tank. The distribution of the heat loss coefficient for the different...

  2. The buoyancy convection during directional solidification of AlZn eutectic

    International Nuclear Information System (INIS)

    Prazak, M.; Procio, M.; Holecek, S.

    1993-01-01

    A study has been made of the effect of buoyancy convection during the directional solidification of AlZn eutectic alloy. Experiments have been conducted using a Bridgman-Stockbarger arrangement with the furnace moving along the specimen. The apparatus rotated around the horizontal axis, which made it possible to carry out measurements at different angles β contained by the gravity and temperature gradient vectors in the specimen. The anisotropy of both the linear thermal expansion coefficient a and the hardness HK measured by the Knoop method has been studied. The dilatation measurements confirmed the expected anisotropy of the linear thermal expansion of directionally solidified specimens. The values of HK correspond with the lamellar spacing measured in the metallographic study. (orig.)

  3. Convection with local thermal non-equilibrium and microfluidic effects

    CERN Document Server

    Straughan, Brian

    2015-01-01

    This book is one of the first devoted to an account of theories of thermal convection which involve local thermal non-equilibrium effects, including a concentration on microfluidic effects. The text introduces convection with local thermal non-equilibrium effects in extraordinary detail, making it easy for readers newer to the subject area to understand. This book is unique in the fact that it addresses a large number of convection theories and provides many new results which are not available elsewhere. This book will be useful to researchers from engineering, fluid mechanics, and applied mathematics, particularly those interested in microfluidics and porous media.

  4. Climate change and local pollution effects. An integrated approach

    International Nuclear Information System (INIS)

    Aaheim, H.A.; Kristin, A.; Seip, H.M.

    1999-01-01

    Few studies on measures for mitigation of damage caused by man-made emissions to the environment have tried to consider all major effects. We illustrate the importance of an integrated approach by estimating costs and benefits of a proposed energy saving program for Hungary, originally designed to reduce CO 2 emissions. The dominant benefit of implementing the program is likely to be reduced health damage from local pollutants. Also reduced costs of material damage and to a lesser extent vegetation damage contribute to make the net benefit considerable. Compared to the reduction in these local and regional effects, the benefits from reducing greenhouse gases are likely to be minor. Since local effects in general occur much earlier after measures have been implemented than effects of increased emissions of greenhouse gases, inclusion of local effects makes evaluation of climate policy less dependent on the choice of discount rate. In our opinion, similar results are likely for many measures originally designed to reduce emissions of greenhouse gases particularly in some areas in developing countries with high local pollution levels. Main uncertainties in the analysis, e.g. in the relationships between damage and pollution level, are discussed. 72 refs

  5. Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

    Science.gov (United States)

    Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

    2018-02-01

    The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

  6. Assessment of RANS and LES Turbulence Modeling for Buoyancy-Aided/Opposed Forced and Mixed Convection

    Science.gov (United States)

    Clifford, Corey; Kimber, Mark

    2017-11-01

    Over the last 30 years, an industry-wide shift within the nuclear community has led to increased utilization of computational fluid dynamics (CFD) to supplement nuclear reactor safety analyses. One such area that is of particular interest to the nuclear community, specifically to those performing loss-of-flow accident (LOFA) analyses for next-generation very-high temperature reactors (VHTR), is the capacity of current computational models to predict heat transfer across a wide range of buoyancy conditions. In the present investigation, a critical evaluation of Reynolds-averaged Navier-Stokes (RANS) and large-eddy simulation (LES) turbulence modeling techniques is conducted based on CFD validation data collected from the Rotatable Buoyancy Tunnel (RoBuT) at Utah State University. Four different experimental flow conditions are investigated: (1) buoyancy-aided forced convection; (2) buoyancy-opposed forced convection; (3) buoyancy-aided mixed convection; (4) buoyancy-opposed mixed convection. Overall, good agreement is found for both forced convection-dominated scenarios, but an overly-diffusive prediction of the normal Reynolds stress is observed for the RANS-based turbulence models. Low-Reynolds number RANS models perform adequately for mixed convection, while higher-order RANS approaches underestimate the influence of buoyancy on the production of turbulence.

  7. Effects of local and global network connectivity on synergistic epidemics

    Science.gov (United States)

    Broder-Rodgers, David; Pérez-Reche, Francisco J.; Taraskin, Sergei N.

    2015-12-01

    Epidemics in networks can be affected by cooperation in transmission of infection and also connectivity between nodes. An interplay between these two properties and their influence on epidemic spread are addressed in the paper. A particular type of cooperative effects (called synergy effects) is considered, where the transmission rate between a pair of nodes depends on the number of infected neighbors. The connectivity effects are studied by constructing networks of different topology, starting with lattices with only local connectivity and then with networks that have both local and global connectivity obtained by random bond-rewiring to nodes within a certain distance. The susceptible-infected-removed epidemics were found to exhibit several interesting effects: (i) for epidemics with strong constructive synergy spreading in networks with high local connectivity, the bond rewiring has a negative role in epidemic spread, i.e., it reduces invasion probability; (ii) in contrast, for epidemics with destructive or weak constructive synergy spreading on networks of arbitrary local connectivity, rewiring helps epidemics to spread; (iii) and, finally, rewiring always enhances the spread of epidemics, independent of synergy, if the local connectivity is low.

  8. Understanding local residents of Korea using nuclear effective safety

    International Nuclear Information System (INIS)

    Chung, Yun Hyung; Lee, Gey Hwi; Hah, Yeonhee; Kim, Beom Jun

    2010-01-01

    The risk perception gap between experts and lay people is based on the use of different concept on risk. It is getting increasingly important for nuclear practitioners to understand the lay people's subjective perception on nuclear safety. We proposed the nuclear effective safety index (NESI) which is based on data of the public survey of local inhabitants. We extracted the four factors for effective safety indicators; communication, trust, plant emergency response capability, and personal emergency coping skills. The latest NESI was 41.54, which was increased from 38.22 but still low. The three-year data of NESI showed the differences between genders and between sites as well as trend. The survey of antecedents of effective safety showed some meaningful events and profound differences between plant employees and local inhabitants. The NESI can be utilized as useful communication tool between the local inhabitants and nuclear practitioners. (authors)

  9. Analysis of the strength of sea gas pipelines of positive buoyancy conditioned by glaciation

    Science.gov (United States)

    Malkov, Venyamin; Kurbatova, Galina; Ermolaeva, Nadezhda; Malkova, Yulia; Petrukhin, Ruslan

    2018-05-01

    A technique for estimating the stress state of a gas pipeline laid along the seabed in northern latitudes in the presence of glaciation is proposed. It is assumed that the pipeline lies on the bottom of the seabed, but under certain conditions on the some part of the pipeline a glaciation is formed and the gas pipeline section in the place of glaciation can come off the ground due to the positive buoyancy of the ice. Calculation of additional stresses caused by bending of the pipeline is of practical interest for strength evaluation. The gas pipeline is a two-layer cylindrical shell of circular cross section. The inner layer is made of high-strength steel, the outer layer is made of reinforced ferroconcrete. The proposed methodology for calculating the gas pipeline for strength is based on the equations of the theory of shells. The procedure takes into account the effect of internal gas pressure, external pressure of sea water, the weight of two-layer gas pipeline and the weight of the ice layer. The lifting force created by the displaced fluid and the positive buoyancy of the ice is also taken into account. It is significant that the listed loads cause only two types of deformation of the gas pipeline: axisymmetric and antisymmetric. The interaction of the pipeline with the ground as an elastic foundation is not considered. The main objective of the research is to establish the fact of separation of part of the pipeline from the ground. The method of calculations of stresses and deformations occurring in a model sea gas pipeline is presented.

  10. Methodology of investment effectiveness evaluation in the local energy market

    Energy Technology Data Exchange (ETDEWEB)

    Kamrat, W.

    1999-07-01

    The paper presents issues of investment effectiveness evaluation in the local energy market. Results of research presented in the paper are mainly proposing a concept of a methodology which allows the evaluation of investment processes in regional power markets at the decision-making stage. In this respect, selecting a rational investment strategy is an important stage of the entire investment process. In view of criteria of various nature, the construction of a methodology of investment effectiveness bears an especially important meaning for a local decision-maker or investor. It is of particular significance to countries that are undergoing a transition from a centrally planned economy to a market economy. (orig.)

  11. The effect of local tramadol injection in post appendectomy pain

    OpenAIRE

    Alireza Khazaei; Farshid Arbabi-Kalati; Soheil Borumand; Reza Rooshanravan

    2012-01-01

    Background: It has been demonstrated that tramadol, asemisynthetic opioid, is an effective analgesic with systemic (central) and local (peripheral) anesthetic effects. The aim of this study was to compare the post-operative anesthetic effect of subcutaneous wound infiltration of tramadol with normal saline as placebo in the incision wounds after appendectomy and measuring the average need to petidine during the next 24 hours after the appendectomy. Materials and Method: This double blind stud...

  12. The principle of locality: Effectiveness, fate, and challenges

    International Nuclear Information System (INIS)

    Doplicher, Sergio

    2010-01-01

    The special theory of relativity and quantum mechanics merge in the key principle of quantum field theory, the principle of locality. We review some examples of its 'unreasonable effectiveness' in giving rise to most of the conceptual and structural frame of quantum field theory, especially in the absence of massless particles. This effectiveness shows up best in the formulation of quantum field theory in terms of operator algebras of local observables; this formulation is successful in digging out the roots of global gauge invariance, through the analysis of superselection structure and statistics, in the structure of the local observable quantities alone, at least for purely massive theories; but so far it seems unfit to cope with the principle of local gauge invariance. This problem emerges also if one attempts to figure out the fate of the principle of locality in theories describing the gravitational forces between elementary particles as well. An approach based on the need to keep an operational meaning, in terms of localization of events, of the notion of space-time, shows that, in the small, the latter must loose any meaning as a classical pseudo-Riemannian manifold, locally based on Minkowski space, but should acquire a quantum structure at the Planck scale. We review the geometry of a basic model of quantum space-time and some attempts to formulate interaction of quantum fields on quantum space-time. The principle of locality is necessarily lost at the Planck scale, and it is a crucial open problem to unravel a replacement in such theories which is equally mathematically sharp, namely, a principle where the general theory of relativity and quantum mechanics merge, which reduces to the principle of locality at larger scales. Besides exploring its fate, many challenges for the principle of locality remain; among them, the analysis of superselection structure and statistics also in the presence of massless particles, and to give a precise mathematical

  13. Macroscopic local-field effects on photoabsorption processes

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Gong Yubing; Wang Meishan; Wang Dehua

    2008-01-01

    The influence of the local-field effect on the photoabsorption cross sections of the atoms which are embedded in the macroscopic medium has been studied by a set of alternative expressions in detail. Some notes on the validity of some different local-field models used to study the photoabsorption cross sections of atoms in condensed matter have been given for the first time. Our results indicate that the local fields can have substantial and different influence on the photoabsorption cross section of atoms in condensed matter for different models. Clausius-Mossotti model and Onsager model have proved to be more reasonable to describe the local field in gas, liquid, or even some simple solid, while Glauber-Lewenstein model probably is wrong in these conditions except for the ideal gas. A procedure which can avoid the errors introduced by Kramers-Kronig transformation has been implemented in this work. This procedure can guarantee that the theoretical studies on the local field effects will not be influenced by the integral instability of the Kramers-Kronig transformation

  14. Local Side Effects of Sublingual and Oral Immunotherapy.

    Science.gov (United States)

    Passalacqua, Giovanni; Nowak-Węgrzyn, Anna; Canonica, Giorgio Walter

    Sublingual immunotherapy (SLIT) is increasingly used worldwide, and several products have been recently registered as drugs for respiratory allergy by the European Medicine Agency and the Food and Drug Administration. Concerning inhalant allergens, the safety of SLIT is overall superior to that of subcutaneous immunotherapy in terms of systemic adverse events. No fatality has been ever reported, and episodes of anaphylaxis were described only exceptionally. Looking at the historical and recent trials, most (>90%) adverse events are "local" and confined to the site of administration. For this reason, a specific grading system has been developed by the World Allergy Organization to classify and describe local adverse events. There is an increasing amount of literature concerning oral desensitization for food allergens, referred to as oral immunotherapy. Also, in this case, local side effects are predominant, although systemic adverse events are more frequent than with inhalant allergens. We review herein the description of local side effects due to SLIT, with a special focus on large trials having a declared sample size calculation. The use of the Medical Dictionary for Regulatory Activities nomenclature for adverse events is mentioned in this context, as recommended by regulatory agencies. It is expected that a uniform classification/grading of local adverse events will improve and harmonize the surveillance and reporting on the safety of SLIT. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  15. Numerical study of effect of oxygen fraction on local entropy ...

    Indian Academy of Sciences (India)

    This study considers numerical simulation of the combustion of methane with air, including oxygen and nitrogen, in a burner and the numerical solution of local entropy generation rate due to high temperature and velocity gradients in the combustion chamber. The effects of equivalence ratio () and oxygen percentage () ...

  16. Strong expectations cancel locality effects: evidence from Hindi.

    Directory of Open Access Journals (Sweden)

    Samar Husain

    Full Text Available Expectation-driven facilitation (Hale, 2001; Levy, 2008 and locality-driven retrieval difficulty (Gibson, 1998, 2000; Lewis & Vasishth, 2005 are widely recognized to be two critical factors in incremental sentence processing; there is accumulating evidence that both can influence processing difficulty. However, it is unclear whether and how expectations and memory interact. We first confirm a key prediction of the expectation account: a Hindi self-paced reading study shows that when an expectation for an upcoming part of speech is dashed, building a rarer structure consumes more processing time than building a less rare structure. This is a strong validation of the expectation-based account. In a second study, we show that when expectation is strong, i.e., when a particular verb is predicted, strong facilitation effects are seen when the appearance of the verb is delayed; however, when expectation is weak, i.e., when only the part of speech "verb" is predicted but a particular verb is not predicted, the facilitation disappears and a tendency towards a locality effect is seen. The interaction seen between expectation strength and distance shows that strong expectations cancel locality effects, and that weak expectations allow locality effects to emerge.

  17. Strong expectations cancel locality effects: evidence from Hindi.

    Science.gov (United States)

    Husain, Samar; Vasishth, Shravan; Srinivasan, Narayanan

    2014-01-01

    Expectation-driven facilitation (Hale, 2001; Levy, 2008) and locality-driven retrieval difficulty (Gibson, 1998, 2000; Lewis & Vasishth, 2005) are widely recognized to be two critical factors in incremental sentence processing; there is accumulating evidence that both can influence processing difficulty. However, it is unclear whether and how expectations and memory interact. We first confirm a key prediction of the expectation account: a Hindi self-paced reading study shows that when an expectation for an upcoming part of speech is dashed, building a rarer structure consumes more processing time than building a less rare structure. This is a strong validation of the expectation-based account. In a second study, we show that when expectation is strong, i.e., when a particular verb is predicted, strong facilitation effects are seen when the appearance of the verb is delayed; however, when expectation is weak, i.e., when only the part of speech "verb" is predicted but a particular verb is not predicted, the facilitation disappears and a tendency towards a locality effect is seen. The interaction seen between expectation strength and distance shows that strong expectations cancel locality effects, and that weak expectations allow locality effects to emerge.

  18. Effect of occupational exposure to local powdered tobacco (snuff) on ...

    African Journals Online (AJOL)

    The effect of occupational exposure to local powdered tobacco (snuff) on pulmonary function was studied. Snuff industry workers in Onitsha and Enugu markets were studied and compared with age-, weight-, and height-matched control not exposed to any known air pollutant. The pulmonary indices studied include; forced ...

  19. Impedes to effective collection of local government revenue and ...

    African Journals Online (AJOL)

    However, the inability of these institutions to effectively collect revenue in Cameroon has hampered service delivery. Following the case of the Wum Central Council, the study holds that tax evasion and defaulting, migration and the diversion of revenue to other Local Government areas as well as underpayments of court ...

  20. Local heterogeneity effects on small-sample worths

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1986-01-01

    One of the parameters usually measured in a fast reactor critical assembly is the reactivity associated with inserting a small sample of a material into the core (sample worth). Local heterogeneities introduced by the worth measurement techniques can have a significant effect on the sample worth. Unfortunately, the capability is lacking to model some of the heterogeneity effects associated with the experimental technique traditionally used at ANL (the radial tube technique). It has been suggested that these effects could account for a large portion of what remains of the longstanding central worth discrepancy. The purpose of this paper is to describe a large body of experimental data - most of which has never been reported - that shows the effect of radial tube-related local heterogeneities

  1. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, 2000-present, Buoyancy Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Buoyancy Flux data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  2. Buoyancy package for self-contained acoustic doppler current profiler mooring

    Digital Repository Service at National Institute of Oceanography (India)

    Venkatesan, R.; Krishnakumar, V.

    A buoyancy package for self-contained Acoustic Doppler Current Profiler(SC-ADCP 1200 RD instruments USA) was designed and fabricated indigenously, for subsurface mooring in coastal waters. The system design is discussed. The design to keep SC...

  3. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, 2000-present, Buoyancy Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Buoyancy Flux data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  4. Numerical and Experimental Study on Negative Buoyance Induced Vortices in N-Butane Jet Flames

    KAUST Repository

    Xiong, Yuan; Cha, Min; Chung, Suk-Ho

    2015-01-01

    Near nozzle flow field in flickering n-butane diffusion jet flames was investigated with a special focus on transient flow patterns of negative buoyance induced vortices. The flow structures were obtained through Mie scattering imaging with seed

  5. Preoperative localization of parathyroid adenomas is cost-effective

    International Nuclear Information System (INIS)

    Wilson, M.A.; Mack, E.; Rowe, B.; Perlman, S.B.

    1986-01-01

    The preoperative localization of parathyroid adenomas is cost-effective because it reduces anesthesia and surgery times. The technique is sensitive in single and double adenomas (90%), and some surgeons have modified their operative technique because of its introduction. The practical experience of one surgeon is presented, with similar patient subsets (n = 22) compared before and after use of a localization scan was instituted. The average operative time fell by 94%, from 2 hours 35 minutes to 1 hour 19 minutes. The reduction in operative time was possible because the surgeon did not seek to identify the remaining normal parathyroids when the scanned lesion was excised and proved to be the adenoma

  6. Effect of altering local protein fluctuations using artificial intelligence

    Science.gov (United States)

    Nishiyama, Katsuhiko

    2017-03-01

    The fluctuations in Arg111, a significantly fluctuating residue in cathepsin K, were locally regulated by modifying Arg111 to Gly111. The binding properties of 15 dipeptides in the modified protein were analyzed by molecular simulations, and modeled as decision trees using artificial intelligence. The decision tree of the modified protein significantly differed from that of unmodified cathepsin K, and the Arg-to-Gly modification exerted a remarkable effect on the peptide binding properties. By locally regulating the fluctuations of a protein, we may greatly alter the original functions of the protein, enabling novel applications in several fields.

  7. Effect of altering local protein fluctuations using artificial intelligence

    Directory of Open Access Journals (Sweden)

    Katsuhiko Nishiyama

    2017-03-01

    Full Text Available The fluctuations in Arg111, a significantly fluctuating residue in cathepsin K, were locally regulated by modifying Arg111 to Gly111. The binding properties of 15 dipeptides in the modified protein were analyzed by molecular simulations, and modeled as decision trees using artificial intelligence. The decision tree of the modified protein significantly differed from that of unmodified cathepsin K, and the Arg-to-Gly modification exerted a remarkable effect on the peptide binding properties. By locally regulating the fluctuations of a protein, we may greatly alter the original functions of the protein, enabling novel applications in several fields.

  8. Local effect of equilibrium current on tearing mode stability

    International Nuclear Information System (INIS)

    Cozzani, F.

    1985-12-01

    The local effect of the equilibrium current on the linear stability of low poloidal number tearing modes in tokamaks is investigated analytically. The plasma response inside the tearing layer is derived from fluid theory and the local equilibrium current is shown to couple to the mode dynamics through its gradient, which is proportional to the local electron temperature gradient under the approximations used in the analysis. The relevant eigenmode equations, expressing Ampere's law and the plasma quasineutrality condition, respectively, are suitably combined in a single integral equation, from which a variational principle is formulated to derive the mode dispersion relations for several cases of interest. The local equilibrium current is treated as a small perturbation of the known results for the m greater than or equal to 2 and the m = 1 tearing modes in the collisional regime, and the m greater than or equal to 2 tearing mode in the semicollisional regime; its effect is found to enhance stabilization for the m greater than or equal to 2 drift-tearing mode in the collisional regime, whereas the m = 1 growth rate is very slightly increased and the stabilizing effect of the parallel thermal conduction on the m greater than or equal to 2 mode in the semicollisional regime is slightly reduced

  9. Spatio-temporal variability in western Baltic cod early life stage survival mediated by egg buoyancy, hydrography and hydrodynamics

    DEFF Research Database (Denmark)

    Hinrichsen, H-H.; Hüssy, K.; Huwer, B.

    2012-01-01

    Spatio-temporal variability in western Baltic cod early life stage survival mediated by egg buoyancy, hydrography and hydrodynamics. – ICES Journal of Marine Science, 69: 1744–1752.To disentangle the effects of different drivers on recruitment variability of marine fish, a spatially and temporally...... explicit understanding of both the spawning stock size and the early life stage dynamics is required. The objectives of this study are to assess the transport of western Baltic cod early life stages as well as the variability in environmentally-mediated survival along drift routes in relation to both...

  10. Buoyancy increase and drag-reduction through a simple superhydrophobic coating

    OpenAIRE

    Hwang, G. B.; Patir, A.; Page, K.; Lu, Y.; Allan, E.; Parkin, I. P.

    2017-01-01

    A superhydrophobic paint was fabricated using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES), TiO2 nanoparticles and ethanol. The paint has potential for aquatic application of a superhydrophobic coating as it induces increased buoyancy and drag reduction. Buoyance testing showed that the reduction of surface energy by superhydrophobic coating made it feasible that glass, a high density material, was supported by the surface tension of water. In a miniature boat sailing test, it was shown...

  11. Influence of Buoyancy Control Performance on Power Production by the Wave Dragon Nissum Bredning Prototype

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Tedd, James; Friis-Madsen, E.

    2007-01-01

    This paper reports on the real sea performance of the buoyancy control system of Wave Dragon, a floating wave energy converter using the overtopping principle. The device operates with the full independent control system which has been tested during three years of operation. The impact of the buo...... of the buoyancy control system performance on the power production is noted. This provides motivation and a target for improved control algorithms....

  12. Effect of localized polycrystalline silicon properties on solar cell performance

    Science.gov (United States)

    Leung, D.; Iles, P. A.; Hyland, S.; Kachare, A.

    1984-01-01

    Several forms of polycrystalline silicon, mostly from cast ingots, (including UCP, SILSO and HEM) were studied. On typical slices, localized properties were studied in two ways. Small area (about 2.5 sq mm) mesa diodes were formed, and localized photovoltaic properties were measured. Also a small area (about .015 sq mm) light spot was scanned across the cells; the light spot response was calibrated to measure local diffusion length directly. Using these methods, the effects of grain boundaries, or of intragrain imperfections were correlated with cell performance. Except for the fine grain portion of SILSO, grain boundaries played only a secondary role in determining cell performance. The major factor was intra-grain material quality and it varied with position in ingots and probably related to solidification procedure.

  13. Opisthorchiasis in Northeastern Thailand: Effect of local environment and culture

    Directory of Open Access Journals (Sweden)

    Beuy Joob

    2015-06-01

    Full Text Available Opisthorchiasis is a kind of trematode infection. This parasitic infestation is a chronic hepatobiliary tract infection and can cause chronic irritation that will finally lead to cholangiocarcinoma. It is highly endemic in northeastern region of Thailand and contributes to many cholangiocarcinoma cases annually. The attempt to control the disease becomes a national policy. However, the sanitation becomes a major underlying factor leading to infection and meanwhile, the poverty and low education of the local people become an important concern. In this opinion, the authors discuss the effect of local environment and culture on opisthorchiasis in northeastern Thailand. Due to the pattern change of local environment, global warming and globalization, the dynamicity can be observed.

  14. Effective theory of rotationally faulted multilayer graphene - the local limit

    International Nuclear Information System (INIS)

    Kindermann, M; First, P N

    2012-01-01

    Interlayer coupling in rotationally faulted graphene multilayers breaks the local sublattice-symmetry of the individual layers. Earlier we have presented a theory of this mechanism, which reduces to an effective Dirac model with space-dependent mass in an important limit. It thus makes a wealth of existing knowledge available for the study of rotationally faulted graphene multilayers. Agreement of this theory with a recent experiment in a strong magnetic field was demonstrated. Here we explore some of the predictions of this theory for the system in zero magnetic field at large interlayer bias, when it becomes local in space. We use that theory to illuminate the physics of localization and velocity renormalization in twisted graphene layers. (paper)

  15. Contribution of local probes in the understanding of mechanical effect on localized corrosion

    International Nuclear Information System (INIS)

    Vignal, Vincent; Oltra, Roland; Mary, Nicolas

    2004-01-01

    Understanding the actual effects of mechanical stresses on the processes leading to pitting corrosion necessitates to develop both a mechanical approach and electrochemical experiments at a microscopic scale. Typical embrittlement can be observed after straining around MnS inclusions on a re-sulfurized 316 stainless steels and their corrosion sensitivity have been classified using the micro-capillary electrochemical cell technique. It has been shown that the numerical simulation of the location of stress gradients is possible before the local electrochemical analysis and could be a very interesting way to define the pitting susceptibility of micro-cracked areas during straining. (authors)

  16. Local thermodynamic mapping for effective liquid density-functional theory

    Science.gov (United States)

    Kyrlidis, Agathagelos; Brown, Robert A.

    1992-01-01

    The structural-mapping approximation introduced by Lutsko and Baus (1990) in the generalized effective-liquid approximation is extended to include a local thermodynamic mapping based on a spatially dependent effective density for approximating the solid phase in terms of the uniform liquid. This latter approximation, called the local generalized effective-liquid approximation (LGELA) yields excellent predictions for the free energy of hard-sphere solids and for the conditions of coexistence of a hard-sphere fcc solid with a liquid. Moreover, the predicted free energy remains single valued for calculations with more loosely packed crystalline structures, such as the diamond lattice. The spatial dependence of the weighted density makes the LGELA useful in the study of inhomogeneous solids.

  17. The effect of sadness on global-local processing.

    Science.gov (United States)

    von Mühlenen, Adrian; Bellaera, Lauren; Singh, Amrendra; Srinivasan, Narayanan

    2018-05-04

    Gable and Harmon-Jones (Psychological Science, 21(2), 211-215, 2010) reported that sadness broadens attention in a global-local letter task. This finding provided the key test for their motivational intensity account, which states that the level of spatial processing is not determined by emotional valence, but by motivational intensity. However, their finding is at odds with several other studies, showing no effect, or even a narrowing effect of sadness on attention. This paper reports two attempts to replicate the broadening effect of sadness on attention. Both experiments used a global-local letter task, but differed in terms of emotion induction: Experiment 1 used the same pictures as Gable and Harmon-Jones, taken from the IAPS dataset; Experiment 2 used a sad video underlaid with sad music. Results showed a sadness-specific global advantage in the error rates, but not in the reaction times. The same null results were also found in a South-Asian sample in both experiments, showing that effects on global/local processing were not influenced by a culturally related processing bias.

  18. Assessment of Constraint Effects based on Local Approach

    International Nuclear Information System (INIS)

    Lee, Tae Rin; Chang, Yoon Suk; Choi, Jae Boong; Seok, Chang Sung; Kim, Young Jin

    2005-01-01

    Traditional fracture mechanics has been used to ensure a structural integrity, in which the geometry independence is assumed in crack tip deformation and fracture toughness. However, the assumption is applicable only within limited conditions. To address fracture covering a broad range of loading and crack geometries, two-parameter global approach and local approach have been proposed. The two-parameter global approach can quantify the load and crack geometry effects by adopting T-stress or Q-parameter but time-consuming and expensive since lots of experiments and finite element (FE) analyses are necessary. On the other hand, the local approach evaluates the load and crack geometry effects based on damage model. Once material specific fitting constants are determined from a few experiments and FE analyses, the fracture resistance characteristics can be obtained by numerical simulation. The purpose of this paper is to investigate constraint effects for compact tension (CT) specimens with different in-plane or out-of-plane size using local approach. Both modified GTN model and Rousselier model are adopted to examine the ductile fracture behavior of SA515 Gr.60 carbon steel at high temperature. The fracture resistance (J-R) curves are estimated through numerical analysis, compared with corresponding experimental results and, then, crack length, thickness and side-groove effects are evaluated

  19. Academic Buoyancy and Academic Outcomes: Towards a Further Understanding of Students with Attention-Deficit/Hyperactivity Disorder (ADHD), Students without ADHD, and Academic Buoyancy Itself

    Science.gov (United States)

    Martin, Andrew J.

    2014-01-01

    Background: Academic buoyancy is students' capacity to successfully overcome setback and challenge that is typical of the ordinary course of everyday academic life. It may represent an important factor on the psycho-educational landscape assisting students who experience difficulties in school and schoolwork. Aims: This study investigated the…

  20. Effects of local mass anomalies in Eoetvoes-like experiments

    International Nuclear Information System (INIS)

    Talmadge, C.; Aronson, S.H.; Fischbach, E.

    1986-01-01

    We consider in detail the effects of local mass anomalies in Eoetvoes-like experiments. It is shown that in the presence of an intermediate-range non-gravitational force, the dominant contributions to both the sign and magnitude of the Eoetvoes anomaly may come from nearby masses and not from the earth as a whole. This observation has important implications in the design and interpretation of future experiments, and in the formulation of unified theories incorporating new intermediate-range forces

  1. Buoyancy-activated cell sorting using targeted biotinylated albumin microbubbles.

    Directory of Open Access Journals (Sweden)

    Yu-Ren Liou

    Full Text Available Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including fluorescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs conjugated with antibodies (i.e., targeted biotin-MBs. Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2 μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10 g for 1 min, and then allowed 1 hour at 4 °C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs, which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44(+ and MDA-MB-453 cells (CD44-, which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44(+ is a commonly used cancer

  2. Localization of effective actions in open superstring field theory

    Science.gov (United States)

    Maccaferri, Carlo; Merlano, Alberto

    2018-03-01

    We consider the construction of the algebraic part of D-branes tree-level effective action from Berkovits open superstring field theory. Applying this construction to the quartic potential of massless fields carrying a specific worldsheet charge, we show that the full contribution to the potential localizes at the boundary of moduli space, reducing to elementary two-point functions. As examples of this general mechanism, we show how the Yang-Mills quartic potential and the instanton effective action of a Dp/D( p - 4) system are reproduced.

  3. Effectiveness of local air quality measures; Effectiviteit van likale luchtkwaliteitsmaatregelen

    Energy Technology Data Exchange (ETDEWEB)

    Van Bommel, R.; Van de Poll, T. [Royal Haskoning DHV, Amersfoort (Netherlands)

    2013-12-15

    This article examines the effects of local air quality measures which are calculated by order of the city of Utrecht. The conclusions are that environmental zones and other local measures contribute to meet the targets and improve public health. It is also explained why this is the case, and the question is raised whether or not national measures would be better [Dutch] Dit artikel gaat in op de effecten van lokale maatregelen die zijn berekend in opdracht van de gemeente Utrecht. De conclusie: milieuzones en andere lokale maatregelen dragen bij aan het halen van normen en leveren gezondheidswinst op. Er wordt uitgelegd waarom dat zo is en de vraag wordt gesteld of landelijke maatregelen niet beter zijn.

  4. Buoyancy and Pressure Driven Flow of Hot Gases in Vertical Shafts with Natural and Forced Ventilation

    Science.gov (United States)

    Tamm, Gunnar; Jaluria, Yogesh

    2003-11-01

    An experimental investigation has been carried out on the buoyancy and pressure induced flow of hot gases in vertical shafts, in order to simulate the propagation of combustion products in elevator shafts due to fire in multilevel buildings. Various geometrical configurations are studied, with regard to natural and forced ventilation imposed at the top or bottom of the vertical shaft. The aspect ratio is taken at a fixed value of 6 and the inflow conditions for the hot gases, at a vent near the bottom, are varied in terms of the Reynolds and Grashof numbers. Temperature measurements within the shaft allow a detailed study of the steady state thermal fields, from which optimal means for smoke alleviation in high-rise building fires may be developed. Flow visualization is also used to study the flow characteristics. The results obtained indicate a wall plume as the primary transport mechanism. Flow recirculation dominates at high Grashof number flows, while increased Reynolds numbers gives rise to greater mixing in the shaft. The development and stability of the flow and its effect on the spread of smoke and hot gases are assessed for the different shaft configurations and inlet conditions. It is found that the fastest smoke removal and lowest shaft temperatures occur for a configuration with natural ventilation at the top and forced ventilation up from the shaft bottom. It is also shown that forced ventilation can be used to arrest smoke spread, as well as to dilute the effects of the fire.

  5. CFD Analysis of the Effect on Buoyancy Due to Terrain Temperature Based on an Integrated DEM and Landsat Infrared Imagery Análisis CFD de vientos convectivos naturales debidos a la temperatura de un terreno basado en un modelo DEM integrado con imágenes infrarrojas Landsat

    Directory of Open Access Journals (Sweden)

    Santiago Giraldo

    2008-12-01

    Full Text Available This paper deals with the influence of concrete structures on atmospheric temperatureand the convection winds generated in the Aburra Valley in Medell´ın,Colombia. This area is characterised by low wind velocities with a high industrydensity. A digital elevation model was used from the Radar ShuttleTopography Mission and post-processed in order to obtain a valid volumetricCFD domain. The construction process includes hole-filling due to imperfectionsin the original radar data, decimation of the original cloud-of-points to reduce the excess of detail in regions with low curvature, and the introductionof a volume of air over the terrain surface (CFD domain. Landsat satellitedata was used to set the terrain temperatures for various material compositions.The converted infrared image was then registered into the CFD domainusing an interpolation technique.Navier–Stokes Equations were solved for buoyant, turbulent flow of compressiblefluids accounting for convection and heat transfer effects. Simulationincludes buoyancy and turbulence flow through the k–epsilon model using thehigh-performance computing facilities of Westgrid (Western Canada ResearchGrid. Preliminary results show wind distributions that compare to the oneobserved at low–altitude in the region.El presente trabajo estudia la influencia de estructuras de concreto en la temperatura atmosférica y los vientos convectivos generados en el Valle de Aburrá en Medellín, Colombia. Esta zona se caracteriza por vientos de bajas velocidades con alta densidad industrial. Un modelo de elevación digital fue obtenido de la misión topográfica del radar Shuttle y post-procesado en aras de obtener un dominio volumétrico CFD válido. El proceso de construcción incluye el parchado de agujeros debidos a imperfectos en los datos originarios del radar, decimación de la nube de puntos original para reducir el exceso de detalle en regiones con baja curvatura y la generación de un volumen de

  6. SIMULATION OF FREE CURRENT FLOWS IN BUOYANCY-DRIVEN VENTILATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    D. V. Abramkina

    2017-01-01

    Full Text Available Objectives. The aim of the study is to analyse the effect of the design and methods for heating the ventilation duct of a buoyancy- driven system on the formation of free convective air currents in it.Methods. The study of free convection under the conditions of interior problem was carried out using the CFD software, based on  the finite volume method with unstructured grid. Ansys Fluent software was used as a calculation tool in the study, due to its having a high convergence of numerical solutions offering full-scale  measurements of convective currents.To evaluate the reliability of  the results obtained, a validation procedure was carried out, allowing us to determine how accurately the selected conceptual model describes the investigated flow through a comparison of experimental and numerical data.Results. The results of numerical modelling of free convective currents occurring in the heated channel of the ventilation system of  the top floor of a multi-storey residential building are presented in  the article. In the course of the study, the air velocity at the entrance to the ventilation duct was found to depend on the calculated  temperature difference θ ˚C for various heating methods. A gradual  increase in the discrepancy between the numerical simulation and  experimental results is observed if the calculated temperature  difference > 20 ° C. This phenomenon is due to the fact that with  increased duct temperature, it is quite difficult to achieve even  heating under actual conditions; this is especially noticeable when  considering the variant when the vertical part of the vent duct and the take-off are both heated. The maximum deviation of the  results is 4.4%. The obtained velocity profiles in the calculated  sections indicate the impact of the ventilation take-off on the nature  of the air flow motion.Conclusion. One of the drawbacks of the existing systems of natural ventilation of residential

  7. Ceramic Spheres—A Novel Solution to Deep Sea Buoyancy Modules

    Science.gov (United States)

    Jiang, Bo; Blugan, Gurdial; Sturzenegger, Philip N.; Gonzenbach, Urs T.; Misson, Michael; Thornberry, John; Stenerud, Runar; Cartlidge, David; Kuebler, Jakob

    2016-01-01

    Ceramic-based hollow spheres are considered a great driving force for many applications such as offshore buoyancy modules due to their large diameter to wall thickness ratio and uniform wall thickness geometric features. We have developed such thin-walled hollow spheres made of alumina using slip casting and sintering processes. A diameter as large as 50 mm with a wall thickness of 0.5–1.0 mm has been successfully achieved in these spheres. Their material and structural properties were examined by a series of characterization tools. Particularly, the feasibility of these spheres was investigated with respect to its application for deep sea (>3000 m) buoyancy modules. These spheres, sintered at 1600 °C and with 1.0 mm of wall thickness, have achieved buoyancy of more than 54%. As the sphere’s wall thickness was reduced (e.g., 0.5 mm), their buoyancy reached 72%. The mechanical performance of such spheres has shown a hydrostatic failure pressure above 150 MPa, corresponding to a rating depth below sea level of 5000 m considering a safety factor of 3. The developed alumina-based ceramic spheres are feasible for low cost and scaled-up production and show great potential at depths greater than those achievable by the current deep-sea buoyancy module technologies. PMID:28773651

  8. Local and non-local effects of spanwise finite perturbations in erodible river bathymetries

    Science.gov (United States)

    Musa, Mirko; Hill, Craig; Guala, Michele

    2015-11-01

    Laboratory experiments were performed to study the effect of axial-flow hydrokinetic turbine models on an erodible river bed under live-bed conditions. Results indicate that the presence of an operating turbine rotor creates a blockage in the mean flow which produces a remarkable geomorphic signature in the migrating bedforms. These impacts affect a local area downstream of the turbines when placed symmetrically with respect to the cross section of the channel. On the other hand, more interesting results are observed with an asymmetric installation of the turbines. This configuration demonstrates a stronger effect on the mean flow, resulting in a larger plan-wise distortion of the mean topography and differential migration patterns of bedforms. Different turbine installation arrangements and hub heights above the mean bed were investigated, focusing mainly on the perturbation of sediment transport characteristics influenced by the turbine wake. Additional results with spanwise modulated submerged walls explore the possibility to control river topography harvesting this type of geomorphic destabilization.

  9. Stereo Imaging Velocimetry of Mixing Driven by Buoyancy Induced Flow Fields

    Science.gov (United States)

    Duval, W. M. B.; Jacqmin, D.; Bomani, B. M.; Alexander, I. J.; Kassemi, M.; Batur, C.; Tryggvason, B. V.; Lyubimov, D. V.; Lyubimova, T. P.

    2000-01-01

    Mixing of two fluids generated by steady and particularly g-jitter acceleration is fundamental towards the understanding of transport phenomena in a microgravity environment. We propose to carry out flight and ground-based experiments to quantify flow fields due to g-jitter type of accelerations using Stereo Imaging Velocimetry (SIV), and measure the concentration field using laser fluorescence. The understanding of the effects of g-jitter on transport phenomena is of great practical interest to the microgravity community and impacts the design of experiments for the Space Shuttle as well as the International Space Station. The aim of our proposed research is to provide quantitative data to the community on the effects of g-jitter on flow fields due to mixing induced by buoyancy forces. The fundamental phenomenon of mixing occurs in a broad range of materials processing encompassing the growth of opto-electronic materials and semiconductors, (by directional freezing and physical vapor transport), to solution and protein crystal growth. In materials processing of these systems, crystal homogeneity, which is affected by the solutal field distribution, is one of the major issues. The understanding of fluid mixing driven by buoyancy forces, besides its importance as a topic in fundamental science, can contribute towards the understanding of how solutal fields behave under various body forces. The body forces of interest are steady acceleration and g-jitter acceleration as in a Space Shuttle environment or the International Space Station. Since control of the body force is important, the flight experiment will be carried out on a tunable microgravity vibration isolation mount, which will permit us to precisely input the desired forcing function to simulate a range of body forces. To that end, we propose to design a flight experiment that can only be carried out under microgravity conditions to fully exploit the effects of various body forces on fluid mixing. Recent

  10. Contraceptive Efficacy and Local Effects of Bioceramic IUD in Rat

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; ZHANG Yuanzhen; YAN Yuhua; CHEN Weimin; LIU Wenhui; ZU Meiping

    2006-01-01

    The contraceptive efficacy and local effects of bioceramic IUD in rat were studied. The experiment was divided into four groups: bioceramic IUD group; stainless steel IUD group; operation control group; normal control group. All IUD samples were put into uterus of rats. The experimental results show that the alumina bioceramic has a strong contraceptive effect for those rats. In bioceramic IUD group the endometrial inflammation reaction was as mild as that in stainless IUD group during the early days (30 days ) and gradually abated with time during the late days (60 days ). The experiments show that the alumina bioceramic has a good biocompatibility and contraceptive effects and hint at the alumina bioceramic IUD may become a more safety reproduction family planning IUD.

  11. Globally and locally supersymmetric effective theories for light fields

    CERN Document Server

    Brizi, Leonardo; Scrucca, Claudio A

    2009-01-01

    We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebrai...

  12. The effects of local blowing perturbations on thermal turbulent structures

    Science.gov (United States)

    Liu, Can; Araya, Guillermo; Leonardi, Stefano; Castillo, Luciano

    2013-11-01

    Blowing is an active flow control technique with several industrial applications, particularly in film cooling of turbine blades. In the past, the effects of localized blowing have been mostly analyzed on the velocity field and its influence of the flow parameters and turbulence structures (Krogstad and Kourakine, 2000). However, little literature can be found on the effects of blowing on the coherent thermal structures. In the present study, an incompressible turbulent channel flow with given steady blowing at the wall is simulated via DNS by means of five spanwise holes. The Reynolds number based on the friction velocity and half channel height is approximately Re = 394 and the molecular Prandtl number is Pr = 0.71. Temperature is considered a passive scalar with isothermal conditions at the wall. Different blowing amplitudes and perturbing angles (with respect to the streamwise direction) are applied to find out their effects on the turbulent thermal structures by means of a two-point correlation analysis. In addition, local reduction and increase of drag are connected to vorticity. The corresponding influence of perturbing amplitudes and angles on the energy budget of thermal fluctuations and turbulent Prandtl numbers are also shown and discussed.

  13. Globally and locally supersymmetric effective theories for light fields

    International Nuclear Information System (INIS)

    Brizi, Leonardo; Gomez-Reino, Marta; Scrucca, Claudio A.

    2009-01-01

    We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebraic and manifestly supersymmetric way, which turns out to hold in the same form both for globally and locally supersymmetric theories, meaning that the process of integrating out heavy modes commutes with the process of switching on gravity. More precisely, for heavy chiral and vector multiplets one has to impose respectively stationarity of the superpotential and the Kaehler potential.

  14. Strain gradient crystal plasticity effects on flow localization

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    for metals described by the reformulated Fleck-Hutchinson strain gradient plasticity theory. The theory is implemented numerically within a finite element framework using slip rate increments and displacement increments as state variables. The formulation reduces to the classical crystal plasticity theory...... in the absence of strain gradients. The model is used to study the effect of an internal material length scale on the localization of plastic flow in shear bands in a single crystal under plane strain tension. It is shown that the mesh sensitivity is removed when using the nonlocal material model considered...

  15. Local field effects and metamaterials based on colloidal quantum dots

    International Nuclear Information System (INIS)

    Porvatkina, O V; Tishchenko, A A; Strikhanov, M N

    2015-01-01

    Metamaterials are composite structures that exhibit interesting and unusual properties, e.g. negative refractive index. In this article we consider metamaterials based on colloidal quantum dots (CQDs). We investigate these structures taking into account the local field effects and theoretically analyze expressions for permittivity and permeability of metamaterials based on CdSe CQDs. We obtain inequality describing the conditions when material with definite concentration of CQDs is metamaterial. Also we investigate how the values of dielectric polarizability and magnetic polarizability of CQDs depend on the dots radius and properties the material the quantum dots are made of. (paper)

  16. Can the hadron effective interaction be local in inclusive process

    International Nuclear Information System (INIS)

    Logunov, A.A.; Mestvirishvily, M.A.; Petrov, V.A.

    1974-01-01

    The behaviour of the inclusive spectrum fsub(ab→c) in the asymptotic region is discussed. On the basis of the Jost-Lehmann-Dyson representation it is shown that inclusive processes are described by some structure functions, depending only on ν, q 2 (ν=2psub(b)(psub(a)-psub(c)); q 2 =(psub(a)-psub(c)) 2 ) under certain restrictions on the J-L-D spectral functions. As these dynamical characteristics (structure functions) do not depend on the sum(psub(a)+psub(c)), the effective interaction of hadrons ''a'' and ''c'' is as if local

  17. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    KAUST Repository

    Kong, X.; Delshad, M.; Wheeler, M. F.

    2012-01-01

    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  18. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    KAUST Repository

    Kong, X.

    2012-11-03

    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  19. Turbulent mixed buoyancy driven flow and heat transfer in lid driven enclosure

    International Nuclear Information System (INIS)

    Mishra, Ajay Kumar; Sharma, Anil Kumar

    2015-01-01

    Turbulent mixed buoyancy driven flow and heat transfer of air in lid driven rectangular enclosure has been investigated for Grashof number in the range of 10 8 to 10 11 and for Richardson number 0.1, 1 and 10. Steady two dimensional Reynolds-Averaged-Navier-Stokes equations and conservation equations of mass and energy, coupled with the Boussinesq approximation, are solved. The spatial derivatives in the equations are discretized using the finite-element method. The SIMPLE algorithm is used to resolve pressure-velocity coupling. Turbulence is modeled with the k-ω closure model with physical boundary conditions along with the Boussinesq approximation, for the flow and heat transfer. The predicted results are validated against benchmark solutions reported in literature. The results include stream lines and temperature fields are presented to understand flow and heat transfer characteristics. There is a marked reduction in mean Nusselt number (about 58%) as the Richardson number increases from 0.1 to 10 for the case of Ra=10 10 signifying the effect of reduction of top lid velocity resulting in reduction of turbulent mixing. (author)

  20. Marangoni-buoyancy convection in binary fluids under varying noncondensable concentrations

    Science.gov (United States)

    Li, Yaofa; Yoda, Minami

    2014-11-01

    Marangoni-buoyancy convection in binary fluids in the presence of phase change is a complex and poorly understood problem. Nevertheless, this flow is of interest in evaporative cooling because solutocapillary stresses could reduce film dryout. Convection was therefore studied in methanol-water (MeOH-H2O) layers of depth h ~ 1 - 3 mm confined in a sealed rectangular cell driven by horizontal temperature differences of ~6° C applied over ~ 5 cm. Particle-image velocimetry (PIV) was used to study how varying the fraction of noncondensables (i.e., air) ca from ~ 7 mol% to ambient conditions in the vapor space affects soluto- and thermocapillary stresses in this flow. Although solutocapillary stresses can be used to drive the flow towards hot regions, solutocapillarity appears to have the greatest effect on the flow at small ca, because noncondensables suppress phase change and hence the gradient in the liquid-phase composition at the interface. Surprisingly, convection at ca ~ 50 % leads to a very weak flow and significant condensation in the central portion of the layer i.e., away from the heated and cooled walls). Supported by ONR.

  1. Direct numerical simulation of vacillation in convection induced by centrifugal buoyancy

    Science.gov (United States)

    Pitz, Diogo B.; Marxen, Olaf; Chew, John W.

    2017-11-01

    Flows induced by centrifugal buoyancy occur in industrial systems, such as in the compressor cavities of gas turbines, as well as in flows of geophysical interest. In this numerical study we use direct numerical simulation (DNS) to investigate the transition between the steady waves regime, which is characterized by great regularity, to the vacillation regime, which is critical to understand transition to the fully turbulent regime. From previous work it is known that the onset of convection occurs in the form of pairs of nearly-circular rolls which span the entire axial length of the cavity, with small deviations near the parallel, no-slip end walls. When non-linearity sets in triadic interactions occur and, depending on the value of the centrifugal Rayleigh number, the flow is dominated by either a single mode and its harmonics or by broadband effects if turbulence develops. In this study we increase the centrifugal Rayleigh number progressively and investigate mode interactions during the vacillation regime which eventually lead to chaotic motion. Diogo B. Pitz acknowledges the financial support from the Capes foundation through the Science without Borders program.

  2. Buoyancy increase and drag-reduction through a simple superhydrophobic coating.

    Science.gov (United States)

    Hwang, Gi Byoung; Patir, Adnan; Page, Kristopher; Lu, Yao; Allan, Elaine; Parkin, Ivan P

    2017-06-08

    A superhydrophobic paint was fabricated using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES), TiO 2 nanoparticles and ethanol. The paint has potential for aquatic application of a superhydrophobic coating as it induces increased buoyancy and drag reduction. Buoyance testing showed that the reduction of surface energy by superhydrophobic coating made it feasible that glass, a high density material, was supported by the surface tension of water. In a miniature boat sailing test, it was shown that the low energy surface treatment decreased the adhesion of water molecules to the surface of the boat resulting in a reduction of the drag force. Additionally, a robust superhydrophobic surface was fabricated through layer-by-layer coating using adhesive double side tape and the paint, and after a 100 cm abrasion test with sand paper, the surface still retained its water repellency, enhanced buoyancy and drag reduction.

  3. A new method of producing local enhancement of buoyancy in liquid flows

    Science.gov (United States)

    Bhat, G. S.; Narasimha, R.; Arakeri, V. H.

    1989-11-01

    We describe here a novel method of generating large volumetric heating in a liquid. The method uses the principle of ohmic heating of the liquid, rendered electrically conducting by suitable additives if necessary. Electrolysis is prevented by the use of high frequency alternating voltage and chemically treated electrodes. The technique is demonstrated by producing substantial heating in an initially neutral jet of water. Simple flow visualisation studies, made by adding dye to the jet, show marked changes in the growth and development of the jet with heat addition.

  4. Buoyancy-stirring interactions in a subtropical embayment: a ...

    African Journals Online (AJOL)

    A potential energy anomaly model was used to demonstrate that this periodic component of stratification was largely a result of tidal straining acting locally, with an additional contribution of stratified water advected from outside the bay during the last stages of the flood tide. Simulations using the Delft3D-Flow hydrodynamic ...

  5. Relativistic effects in local inertial frames including parametrized-post-Newtonian effects

    International Nuclear Information System (INIS)

    Shahid-Saless, B.; Ashby, N.

    1988-01-01

    We use the concept of a generalized Fermi frame to describe relativistic effects, due to local and distant sources of gravitation, on a body placed in a local inertial frame of reference. In particular we have considered a model of two spherically symmetric gravitating point sources, moving in circular orbits around a common barycenter where one of the bodies is chosen to be the local and the other the distant one. This has been done using the slow-motion, weak-field approximation and including four of the parametrized-post-Newtonian (PPN) parameters. The position of the classical center of mass must be modified when the PPN parameter zeta 2 is included. We show that the main relativistic effect on a local satellite is described by the Schwarzschild field of the local body and the nonlinear term corresponding to the self-interaction of the local source with itself. There are also much smaller terms that are proportional, respectively, to the product of the potentials of local and distant bodies and to the distant body's self-interactions. The spatial axes of the local frame undergo geodetic precession. In addition we have an acceleration of the order of 10/sup -11/ cm sec -2 that vanish in the case of general relativity, which is discussed in detail

  6. An experimental and analytical study of a buoyancy driven cooling system for a particle accelerator

    International Nuclear Information System (INIS)

    Campbell, B.; Ranganathan, R.

    1993-05-01

    A buoyancy driven closed-loop cooling system that transports the heat generated in a particle accelerator to the ambient has been evaluated both through experiments performed earlier and analysis techniques developed elsewhere. Excellent comparisons between measurements and calculations have been obtained. The model illustrates the feasibility (from a heat transfer viewpoint) of such a cooling system for a particle accelerator

  7. An experimental and analytical study of a buoyancy driven cooling system for a particle accelerator

    International Nuclear Information System (INIS)

    Campbell, B.; Ranganathan, R.

    1993-01-01

    A buoyancy driven closed-loop cooling system that transports the heat generated in a particle accelerator to the ambient has been evaluated both through experiments performed earlier and analysis techniques developed elsewhere. Excellent comparisons between measurements and calculations have been obtained. The model illustrates the feasibility (from a heat transfer viewpoint) of such a cooling system for a particle accelerator

  8. Core-annular flow through a horizontal pipe : Hydrodynamic counterbalancing of buoyancy force on core

    NARCIS (Netherlands)

    Ooms, G.; Vuik, C.; Poesio, P.

    2007-01-01

    A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference

  9. On the influence of buoyancy and suction/injection In Heat and Mass ...

    African Journals Online (AJOL)

    In this paper, we examined the influence of buoyancy and suction/injection in the problem of unsteady convection with chemical reaction and radiative heat transfer past a flat porous plate moving through a binary mixture in an optically thin environment is presented. The dimensionless governing equations for this ...

  10. "'Sink or Swim': Buoyancy and Coping in the Cognitive Test Anxiety--Academic Performance Relationship"

    Science.gov (United States)

    Putwain, David W.; Daly, Anthony L.; Chamberlain, Suzanne; Sadreddini, Shireen

    2016-01-01

    This study explores the relationship between students' self-report levels of cognitive test anxiety (worry), academic buoyancy (withstanding and successfully responding to routine school challenges and setbacks), coping processes and their achieved grades in high-stakes national examinations at the end of compulsory schooling. The sample comprised…

  11. Numerical investigation of the onset of centrifugal buoyancy in a rotating cavity

    Science.gov (United States)

    Pitz, Diogo B.; Marxen, Olaf; Chew, John

    2016-11-01

    Buoyancy-induced flows in a differentially heated rotating annulus present a multitude of dynamics when control parameters such as rotation rate, temperature difference and Prandtl number are varied. Whilst most of the work in this area has been motivated by applications involving geophysics, the problem of buoyancy-induced convection in rotating systems is also relevant in industrial applications such as the flow between rotating disks of turbomachinery internal air systems, in which buoyancy plays a major role and poses a challenge to accurately predict temperature distributions and heat transfer rates. In such applications the rotational speeds involved are very large, so that the centrifugal accelerations induced are much higher than gravity. In this work we perform direct numerical simulations and linear stability analysis of flow induced by centrifugal buoyancy in a sealed rotating annulus of finite gap with flat end-walls, using a canonical setup representative of an internal air system rotating cavity. The analysis focuses on the behaviour of small-amplitude disturbances added to the base flow, and how those affect the onset of Rossby waves and, ultimately, the transition to a fully turbulent state where convection columns no longer have a well-defined structure. Diogo B. Pitz acknowledges the financial support from the Capes foundation through the Science without Borders program.

  12. Annual and seasonal mean buoyancy fluxes for the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, T.G.

    . The fluxes of heat and freshwater across the air-sea interface, and hence the surface buoyancy flux, show strong spatial and temporal variability. The Bay of Bengal and eastern equatorial Indian Ocean are characterized by a net freshwater gain due to heavy...

  13. Non-Uniqueness of the Point of Application of the Buoyancy Force

    Science.gov (United States)

    Kliava, Janis; Megel, Jacques

    2010-01-01

    Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the…

  14. Non-uniqueness of the point of application of the buoyancy force

    International Nuclear Information System (INIS)

    Kliava, Janis; Megel, Jacques

    2010-01-01

    Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the cross-section of a floating body and for an arbitrary angle of heel. We show that the location of the point of application of the buoyancy force essentially depends (i) on the type of motion experienced by the floating body and (ii) on the definition of this point. In a rolling/pitching motion, considerations involving the rotational moment lead to a particular dynamical point of application of the buoyancy force, and for some simple shapes of the floating body this point coincides with the well-known metacentre. On the other hand, from the work-energy relation it follows that in the rolling/pitching motion the energetical point of application of this force is rigidly connected to the centre of buoyancy; in contrast, in a vertical translation this point is rigidly connected to the centre of gravity of the body. Finally, we consider the location of the characteristic points of the floating bodies for some particular shapes of immersed cross-sections. The paper is intended for higher education level physics teachers and students.

  15. Anisotropy and buoyancy in nuclear turbulent heat transfer - critical assessment and needs for modelling

    International Nuclear Information System (INIS)

    Groetzbach, G.

    2007-12-01

    Computational Fluid Dynamics (CFD) programs have a wide application field in reactor technique, like to diverse flow types which have to be considered in Accelerator Driven nuclear reactor Systems (ADS). This requires turbulence models for the momentum and heat transfer with very different capabilities. The physical demands on the models are elaborated for selected transport mechanisms, the status quo of the modelling is discussed, and it is investigated which capabilities are offered by the market dominating commercial CFD codes. One topic of the discussion is on the already earlier achieved knowledge on the distinct anisotropy of the turbulent momentum and heat transport near walls. It is shown that this is relevant in channel flows with inhomogeneous wall conditions. The related consequences for the turbulence modelling are discussed. The second topic is the turbulent heat transport in buoyancy influenced flows. The only turbulence model for heat transfer which is available in the large commercial CFD-codes is based on the Reynolds analogy. This means, it is required to prescribe suitable turbulent Prandtl number distributions. There exist many correlations for channel flows, but they are seldom used in practical applications. Here, a correlation is deduced for the local turbulent Prandtl number which accounts for many parameters, like wall distance, molecular Prandtl number of the fluid, wall roughness and local shear stress, thermal wall condition, etc. so that it can be applied to most ADS typical heat transporting channel flows. The spatial dependence is discussed. It is shown that it is essential for reliable temperature calculations to get accurate turbulent Prandtl numbers especially near walls. If thermal wall functions are applied, then the correlation for the turbulent Prandtl number has to be consistent with the wall functions to avoid unphysical discretisation dependences. In using Direct Numerical Simulation (DNS) data for horizontal fluid layers it

  16. Effects of Radiofrequency Induced local Hyperthermia on Normal Canine Liver

    International Nuclear Information System (INIS)

    Suh, Chang Ok; Loh, John J. K.; Seong, Jin Sil

    1991-01-01

    In order to assess the effects of radiofrequency-induced local hyperthermia on the normal liver, histopathologic findings and biochemical changes after localized hyperthermia in canine liver were studied. Hyperthermia was externally administered using the Thermotron RF-8 (Yamamoto Vinyter Co., Japan; Capacitive type heating machine) with parallel opposed electrodes. Thirteen dogs were used and allocated into one control group (N=3) and two treatment groups according to the treatment temperature. Group I (N=5) was heated with 42.5±0.5.deg.C for 30 minutes, and Group(N=5) was heated with 45±0.5.deg.C for 15-30 minutes. Samples of liver tissue were obtained through a needle biopsy immediately after hyperthermia and 7, 14 and 28 days after treatment and examined for SGOT, SGPT and alkaline phosphatase. Although SGOT and SGPT were elevated after hyperthermia in both groups (three of five in each group), there was no liver cell necrosis or hyperthermia related mortality in Group I. A hydropic swelling of hepatocytes was prominent histologic finding. Hyperthermia with 45.deg.C for 30 minutes was fatal and showed extensive liver cell necrosis. In conclusion, liver damage day heat of 42.5±0.5.deg.C for 30 minutes is reversible, and liver damage by heat of 45±0.5.deg.C for 30 minutes can be fatal or irreversible. However, these results cannot be applied directly to human trial. Therefore, in order to apply hyperthermic treatment on human liver tumor safely, close observation of temperature with proper thermometry is mandatory. Hyperthermic treatment should be confined to the tumor area while sparing a normal liver as much as possible

  17. Magnetic Island Growth A comparison of local and global effects

    International Nuclear Information System (INIS)

    Lloyd, S.S.; Gardner, H.J.

    2003-01-01

    In stellarators a hot plasma is confined to a torus by a magnetic field with both toroidal and poloidal components generated by external currents. Plasma currents develop to balance the pressure gradient with a J x B force which in turn change the shape of confining magnetic field. Self-consistent equilibrium magnetic fields and plasma currents for some H-1NF configurations were calculated using the HINT code. This code relaxes a simplified set of resistive MHD equations on a coordinate grid until an equilibrium is reached [1]. Islands can occur in the equilibrium magnetic field, surrounding field lines with low-order rational rotational transform. The island widths are influenced by four types of currents. External currents determine the vacuum island widths. Global resonant and non-resonant currents increase linearly with plasma pressure and can act in or out of phase to the external currents. Local resonant currents are caused by the presence of an island and reinforce or counteract the island depending on the field strength gradient [2]. We compare the impact of local resonant and global non-resonant currents by comparing the results of HINT for several related configurations of H-1NF. Two configurations with slightly different rotational transforms (but otherwise very similar parameters) will have very different resonant plasma currents but nearly identical non-resonant plasma currents. Comparing the effect of the currents of the two configurations on island width gives an insight into the different contributions of resonant and non-resonant plasma currents to island growth or self-healing

  18. Local effects of ECRH on argon transport at ASDEX upgrade

    International Nuclear Information System (INIS)

    Sertoli, Marco

    2010-01-01

    Future deuterium-tritium magnetically confined fusion power plants will most probably rely an high-Z Plasma Facing Components (PFCs) such as tungsten. This choice is determined by the necessity of low erosion of the first wall materials (to guarantee a long lifetime of the wall components) and by the need to avoid the too high tritium wall retention of typical carbon based PFCs. The experience gathered at the ASDEX Upgrade (AUG) tokamak has demonstrated the possibility of reliable and high performance plasma operation with a full tungsten-coated first wall. The observed accumulation of tungsten which can lead to excessive radiation losses is mitigated with the use of Electron Cyclotron Resonance Heating (ECRH). Although this impurity control method is routinely performed at AUG, the underlying physics principles are still not clear. This thesis aims an providing further knowledge an the effects of ECRH an the transport of impurities inside the core plasma. The transport of argon has been therefore investigated in-depth in purely ECR heated L-mode (low-confinement) discharges. Studies an impurity transport in centrally ECR heated nitrogen-seeded H-mode (high-confinement) discharges have also been performed. To this scope, a new crystal X-ray spectrometer of the Johann type has been installed an AUG for argon concentration and ion temperature measurements. New methods for the experimental determination of the total argon density through the integrated use of this diagnostic and of the Soft X-Ray (SXR) diode arrays have been developed. This gives the possibility of evaluating the full profiles of the argon transport coefficients from the linear flux-gradient dependency of local argon density. In comparison to classical χ 2 -minimization methods, the approach proposed here delivers transport coefficients intrinsically independent of the modelling of periodic relaxation mechanisms such as those Lied to sawtooth MHD (Magneto-Hydro-Dynamic) activity. Moreover, the good

  19. The effect of local tramadol injection in post appendectomy pain

    Directory of Open Access Journals (Sweden)

    Alireza Khazaei

    2012-02-01

    Full Text Available Background: It has been demonstrated that tramadol, asemisynthetic opioid, is an effective analgesic with systemic (central and local (peripheral anesthetic effects. The aim of this study was to compare the post-operative anesthetic effect of subcutaneous wound infiltration of tramadol with normal saline as placebo in the incision wounds after appendectomy and measuring the average need to petidine during the next 24 hours after the appendectomy. Materials and Method: This double blind study was carried out on 60 patients over 15 years old. Patients were randomly divided in two equal groups. At the end of procedure after repairing fascia 100mg of tramadol that was diluted with water for injection up to 10 cc in one syringe or 10 cc of normal saline in another syringe was infiltrated subcutaneously by surgeon before suturing the skin. The intensity of pain (NRS was recorded in the recovery room, after 6 and 24 hours post-operation as well as total amount of administered petidine in the same period. At the end of study the intensity of pain in the mentioned times and the average use of petidine compared in two groups. Results: A significant difference was noted in the severity of pain between two groups in recovery time, 6 and 24 hours afetr operation that was lower in tramadol group (p<0.0001. Also the average use of petidine was significantly lower in tramadol group in 24 hours (p<0.05. The average severity of pain by NRS in recovery was 5.36 for control (N and 3.08 for tramadol (T groups; and after 6 hours it was 5.36 for (N and 3.36 for (T and after 24 hours reached to 3.08 for (N and 2.08 for (T and the average number of injected 25mg ampoules of petidine was 1.56 in (N and 0.76 in (T.Conclusion: Local wound infiltration of tramadol is a good choice for reduction of post appendectomy pain and decreasing need for high potent opioid analgesics

  20. Magnetomechanical local-global effects in magnetostrictive composite materials

    Science.gov (United States)

    Elhajjar, Rani F.; Law, Chiu T.

    2015-10-01

    A constitutive model for magnetostrictive composite materials (MCMs) that describes the relations among stress, strain, magnetic field, and magnetization Liu and Zheng (2005 Acta Mech. Sin. 21 278-85) is implemented for multiphysics simulation for analysis of non-periodic or non-uniform microstructure effects. The multiphysics models that capture designed and actual microstructural details are used for predicting the responses of magnetostrictive composite materials under various mechanical and magnetic loading conditions. The approach overcomes the limitation with strain gages in the investigation of magnetostrictive strain due to stress localization around magnetostrictive phases. Three-dimensional digital image correlation (3D-DIC) is used to measure the displacements and strain in the composites under fluctuating magnetic fields. The specimens are prepared using epoxy and particulate magnetostrictive materials with the particles in the range of approximately 20 to 300 microns range. We examine the displacement and strain fields obtained and compare the results to those obtained from fiber Bragg grating (FBG) measurements. The coupling coefficients obtained from this method were in agreement with those measured using other techniques. The validated model allows us to predict the effect of curing, preload, microstructure alignment and particle shape on the magnetostrictive strains.

  1. Magnetomechanical local-global effects in magnetostrictive composite materials

    International Nuclear Information System (INIS)

    Elhajjar, Rani F; Law, Chiu T

    2015-01-01

    A constitutive model for magnetostrictive composite materials (MCMs) that describes the relations among stress, strain, magnetic field, and magnetization Liu and Zheng (2005 Acta Mech. Sin. 21 278–85) is implemented for multiphysics simulation for analysis of non-periodic or non-uniform microstructure effects. The multiphysics models that capture designed and actual microstructural details are used for predicting the responses of magnetostrictive composite materials under various mechanical and magnetic loading conditions. The approach overcomes the limitation with strain gages in the investigation of magnetostrictive strain due to stress localization around magnetostrictive phases. Three-dimensional digital image correlation (3D-DIC) is used to measure the displacements and strain in the composites under fluctuating magnetic fields. The specimens are prepared using epoxy and particulate magnetostrictive materials with the particles in the range of approximately 20 to 300 microns range. We examine the displacement and strain fields obtained and compare the results to those obtained from fiber Bragg grating (FBG) measurements. The coupling coefficients obtained from this method were in agreement with those measured using other techniques. The validated model allows us to predict the effect of curing, preload, microstructure alignment and particle shape on the magnetostrictive strains. (paper)

  2. Nonlinear simulations of particle source effects on edge localized mode

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.; Tang, C. J. [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, S. Y., E-mail: sychen531@163.com [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Southwestern Institute of Physics, Chengdu 610041 (China); Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China)

    2015-12-15

    The effects of particle source (PS) with different intensities and located positions on Edge Localized Mode (ELM) are systematically studied with BOUT++ code. The results show the ELM size strongly decreases with increasing the PS intensity once the PS is located in the middle or bottom of the pedestal. The effects of PS on ELM depend on the located position of PS. When it is located at the top of the pedestal, peeling-ballooning (P-B) modes can extract more free energy from the pressure gradient and grow up to be a large filament at the initial crash phase and the broadening of mode spectrum can be suppressed by PS, which leads to more energy loss. When it is located in the middle or bottom of the pedestal, the extraction of free energy by P-B modes can be suppressed, and a small filament is generated. During the turbulence transport phase, the broader mode spectrum suppresses the turbulence transport when PS is located in the middle, while the zonal flow plays an important role in damping the turbulence transport when PS is located at the bottom.

  3. Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei.

    Directory of Open Access Journals (Sweden)

    Itsumi Nakamura

    Full Text Available We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200-300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200-300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes, indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats.

  4. Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei.

    Science.gov (United States)

    Nakamura, Itsumi; Meyer, Carl G; Sato, Katsufumi

    2015-01-01

    We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei) in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200-300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200-300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes), indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath) or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats.

  5. Tail thrust of bluefish Pomatomus saltatrix at different buoyancies, speeds, and swimming angles.

    Science.gov (United States)

    Ogilvy, C S; DuBois, A B

    1982-06-01

    1. The tail thrust of bluefish Pomatomus saltatrix was measured using a body accelerometer at different water speeds, buoyancies, and angles of water flow to determine the contribution of tail thrust in overcoming parasitic drag, induced drag, and weight directed along the track. The lengths and weights of the fish averaged 0.52 m and 1.50 kg respectively. 2. The tail thrust overcoming parasitic drag in Newtons, as measured during neutral buoyancy, was: 0.51 x speed + 0.15, with a standard error of estimate of 0.09 N. 3. When buoyancy was altered by the introduction or removal of air from a balloon implanted in the swim bladder, the tail thrust was altered by an amount of the same order as the value calculated for the induced drag of the pectoral fins. 4. The component of weight directed backward along the track was the weight in water multiplied by the sine of the angle of the swimming tunnel relative to horizontal. When this force was added to the calculated induced drag and tail thrust measured at neutral buoyancy, the rearward force equal to the tail thrust, at 45 ml negative buoyancy, 0.5 m s-1, and 15 degrees head up, was 0.12 N due to weight + 0.05 N due to induced drag + 0.40 N due to parasitic drag = 0.57 N total rearward force. 5. The conditions required for gliding were not achieved in our bluefish because the drag exceeded the component of the weight in water directed forward along the track at speeds above the stalling speed of the pectoral fins.

  6. Rotational effects on turbine blade cooling

    Energy Technology Data Exchange (ETDEWEB)

    Govatzidakis, G.J.; Guenette, G.R.; Kerrebrock, J.L. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-10-01

    An experimental investigation of the influence of rotation on the heat transfer in a smooth, rectangular passage rotating in the orthogonal mode is presented. The passage simulates one of the cooling channels found in gas turbine blades. A constant heat flux is imposed on the model with either inward or outward flow. The effects of rotation and buoyancy on the Nusselt number were quantified by systematically varying the Rotation number, Density Ratio, Reynolds number, and Buoyancy parameter. The experiment utilizes a high resolution infrared temperature measurement technique in order to measure the wall temperature distribution. The experimental results show that the rotational effects on the Nusselt number are significant and proper turbine blade design must take into account the effects of rotation, buoyancy, and flow direction. The behavior of the Nusselt number distribution depends strongly on the particular side, axial position, flow direction, and the specific range of the scaling parameters. The results show a strong coupling between buoyancy and Corollas effects throughout the passage. For outward flow, the trailing side Nusselt numbers increase with Rotation number relative to stationary values. On the leading side, the Nusselt numbers tended to decrease with rotation near the inlet and subsequently increased farther downstream in the passage. The Nusselt numbers on the side walls generally increased with rotation. For inward flow, the Nusselt numbers generally improved relative to stationary results, but increases in the Nusselt number were relatively smaller than in the case of outward flow. For outward and inward flows, increasing the density ratio generally tended to decrease Nusselt numbers on the leading and trailing sides, but the exact behavior and magnitude depended on the local axial position and specific range of Buoyancy parameters.

  7. Large Eddy simulation of turbulence: A subgrid scale model including shear, vorticity, rotation, and buoyancy

    Science.gov (United States)

    Canuto, V. M.

    1994-01-01

    The Reynolds numbers that characterize geophysical and astrophysical turbulence (Re approximately equals 10(exp 8) for the planetary boundary layer and Re approximately equals 10(exp 14) for the Sun's interior) are too large to allow a direct numerical simulation (DNS) of the fundamental Navier-Stokes and temperature equations. In fact, the spatial number of grid points N approximately Re(exp 9/4) exceeds the computational capability of today's supercomputers. Alternative treatments are the ensemble-time average approach, and/or the volume average approach. Since the first method (Reynolds stress approach) is largely analytical, the resulting turbulence equations entail manageable computational requirements and can thus be linked to a stellar evolutionary code or, in the geophysical case, to general circulation models. In the volume average approach, one carries out a large eddy simulation (LES) which resolves numerically the largest scales, while the unresolved scales must be treated theoretically with a subgrid scale model (SGS). Contrary to the ensemble average approach, the LES+SGS approach has considerable computational requirements. Even if this prevents (for the time being) a LES+SGS model to be linked to stellar or geophysical codes, it is still of the greatest relevance as an 'experimental tool' to be used, inter alia, to improve the parameterizations needed in the ensemble average approach. Such a methodology has been successfully adopted in studies of the convective planetary boundary layer. Experienc e with the LES+SGS approach from different fields has shown that its reliability depends on the healthiness of the SGS model for numerical stability as well as for physical completeness. At present, the most widely used SGS model, the Smagorinsky model, accounts for the effect of the shear induced by the large resolved scales on the unresolved scales but does not account for the effects of buoyancy, anisotropy, rotation, and stable stratification. The

  8. The plastic flow localization effect on crystalline material

    International Nuclear Information System (INIS)

    Pajot, A.

    2011-01-01

    Irradiation affects the mechanical properties of materials. In particular, an increase of yield strength followed by a decrease of ductility and a reduction of the elongation to fracture are observed above a threshold irradiation dose. The last two phenomena are correlated with the appearance of bands free of defects (clear bands) in which plastic deformation is confined. These bands also determine accumulation of dislocations at grain boundaries, thereby favouring local grain decohesion and possibly initiating fracture. Clear bands have an important impact on metal resistance, nevertheless our level of understanding is not sufficient to evaluate quantitatively their effect on the loss of ductility and reduction of elongation to fracture that are observed experimentally. A clear band is a microstructural defect, created when loading an irradiated material. Its complex interaction with defects on the nano scale affects the behaviour of the metal at the macroscopic scale. A full understanding implies the application of a multi scale modeling approach. This explains why, even though clear bands have first been

  9. EFFECTS OF LOCAL DISSIPATION PROFILES ON MAGNETIZED ACCRETION DISK SPECTRA

    International Nuclear Information System (INIS)

    Tao, Ted; Blaes, Omer

    2013-01-01

    We present spectral calculations of non-LTE accretion disk models appropriate for high-luminosity stellar mass black hole X-ray binary systems. We first use a dissipation profile based on scaling the results of shearing box simulations of Hirose et al. to a range of annuli parameters. We simultaneously scale the effective temperature, orbital frequency, and surface density with luminosity and radius according to the standard α-model. This naturally brings increased dissipation to the disk surface layers (around the photospheres) at small radii and high luminosities. We find that the local spectrum transitions directly from a modified blackbody to a saturated Compton scattering spectrum as we increase the effective temperature and orbital frequency while decreasing midplane surface density. Next, we construct annuli models based on the parameters of a L/L Edd = 0.8 disk orbiting a 6.62 solar mass black hole using two modified dissipation profiles that explicitly put more dissipation per unit mass near the disk surface. The new dissipation profiles are qualitatively similar to the one found by Hirose et al., but produce strong near power-law spectral tails. Our models also include physically motivated magnetic acceleration support based once again on scaling the Hirose et al. results. We present three full-disk spectra, each based on one of the dissipation prescriptions. Our most aggressive dissipation profile results in a disk spectrum that is in approximate quantitative agreement with certain observations of the steep power-law spectral states from some black hole X-ray binaries.

  10. Environmental pollution has sex-dependent effects on local survival

    Science.gov (United States)

    Eeva, Tapio; Hakkarainen, Harri; Laaksonen, Toni; Lehikoinen, Esa

    2006-01-01

    Environmental pollutants cause a potential hazard for survival in free-living animal populations. We modelled local survival (including emigration) by using individual mark–recapture histories of males and females in a population of a small insectivorous passerine bird, the pied flycatcher (Ficedula hypoleuca) living around a point source of heavy metals (copper smelter). Local survival of F. hypoleuca females did not differ between polluted and unpolluted environments. Males, however, showed a one-third higher local-survival probability in the polluted area. Low fledgling production was generally associated with decreased local survival, but males in the polluted area showed relatively high local survival, irrespective of their fledgling number. A possible explanation of higher local survival of males in the polluted area could be a pollution-induced change in hormone (e.g. corticosterone or testosterone) levels of males. It could make them to invest more on their own survival or affect the hormonal control of breeding dispersal. The local survival of males decreased in the polluted area over the study period along with the simultaneous decrease in heavy metal emissions. This temporal trend is in agreement with the stress hormone hypothesis. PMID:17148387

  11. ROLE OF MAGNETIC FIELD STRENGTH AND NUMERICAL RESOLUTION IN SIMULATIONS OF THE HEAT-FLUX-DRIVEN BUOYANCY INSTABILITY

    International Nuclear Information System (INIS)

    Avara, Mark J.; Reynolds, Christopher S.; Bogdanović, Tamara

    2013-01-01

    The role played by magnetic fields in the intracluster medium (ICM) of galaxy clusters is complex. The weakly collisional nature of the ICM leads to thermal conduction that is channeled along field lines. This anisotropic heat conduction profoundly changes the instabilities of the ICM atmosphere, with convective stabilities being driven by temperature gradients of either sign. Here, we employ the Athena magnetohydrodynamic code to investigate the local non-linear behavior of the heat-flux-driven buoyancy instability (HBI) relevant in the cores of cooling-core clusters where the temperature increases with radius. We study a grid of two-dimensional simulations that span a large range of initial magnetic field strengths and numerical resolutions. For very weak initial fields, we recover the previously known result that the HBI wraps the field in the horizontal direction, thereby shutting off the heat flux. However, we find that simulations that begin with intermediate initial field strengths have a qualitatively different behavior, forming HBI-stable filaments that resist field-line wrapping and enable sustained vertical conductive heat flux at a level of 10%-25% of the Spitzer value. While astrophysical conclusions regarding the role of conduction in cooling cores require detailed global models, our local study proves that systems dominated by the HBI do not necessarily quench the conductive heat flux

  12. Local and global dynamical effects of dark energy

    Science.gov (United States)

    Chernin, A. D.

    Local expansion flows of galaxies were discovered by Lemaitre and Hubble in 1927-29 at distances of less than 25-30 Mpc. The global expansion of the Universe as a whole was predicted theoretically by Friedmann in 1922-24 and discovered in the 1990s in observations at truly cosmological distances of more than 1 000 Mpc. On all these spatial scales, the flows follow a (nearly) linear velocity-distance relation, known now as Hubble's law. This similarity of local and global phenomena is due to the universal dark energy antigravity which dominates the cosmic dynamics on both local and global spatial scales.

  13. Local Recurrence in Rectal Cancer: Anatomic Localization and Effect on Radiation Target

    International Nuclear Information System (INIS)

    Syk, Erik; Torkzad, Michael R.; Blomqvist, Lennart; Nilsson, Per J.; Glimelius, Bengt

    2008-01-01

    Purpose: To determine the sites of local recurrence after total mesorectal excision for rectal cancer in an effort to optimize the radiation target. Methods and Materials: A total of 155 patients with recurrence after abdominal resection for rectal cancer were identified from a population-based consecutive cohort of 2,315 patients who had undergone surgery by surgeons trained in the total mesorectal excision procedure. A total of 99 cross-sectional imaging studies were retrieved and re-examined by one radiologist. The clinical records were examined for the remaining patients. Results: Evidence of residual mesorectal fat was identified in 50 of the 99 patients. In 83 patients, local recurrence was identified on the imaging studies. All recurrences were within the irradiated volume if the patients had undergone preoperative radiotherapy or within the same volume if they had not. The site of recurrence was in the lower 75% of the pelvis, anatomically below the S1-S2 interspace for all patients. Only 5 of the 44 recurrences in patients with primary tumors >5 cm from the anal verge were in the lowest 20% of the pelvis. Six recurrences involved the lateral lymph nodes. Conclusion: These data suggest that a lowering of the upper limit of the clinical target volume could be introduced. The anal sphincter complex with surrounding tissue could also be excluded in patients with primary tumors >5 cm from the anal verge

  14. Astrometric and Timing Effects of Gravitational Waves from Localized Sources

    OpenAIRE

    Kopeikin, Sergei M.; Schafer, Gerhard; Gwinn, Carl R.; Eubanks, T. Marshall

    1998-01-01

    A consistent approach for an exhaustive solution of the problem of propagation of light rays in the field of gravitational waves emitted by a localized source of gravitational radiation is developed in the first post-Minkowskian and quadrupole approximation of General Relativity. We demonstrate that the equations of light propagation in the retarded gravitational field of an arbitrary localized source emitting quadrupolar gravitational waves can be integrated exactly. The influence of the gra...

  15. 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

  16. 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.

  17. 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

  18. Quantum non-locality vs. quasi-local measurements in the conditions of the Aharonov-Bohm effect

    International Nuclear Information System (INIS)

    Gulian, Armen M

    2014-01-01

    Theoretical explanation of the Meissner effect involves proportionality between current density and vector potential, which has many deep consequences. As noticed by de Gennes, superconductors in a magnetic field 'find an equilibrium state where the sum of kinetic and magnetic energies is minimum' and this state 'corresponds to the expulsion of the magnetic field'. This statement still leaves an open question: from which source is the superconducting current acquiring its kinetic energy? A naïve answer, perhaps, is from the energy of the magnetic field. However, one can consider situations (Aharonov-Bohm effect), where the classical magnetic field is locally absent in the area occupied by the current. Experiments demonstrate that despite the local absence of the magnetic field, current is, nevertheless, building up. From what source is it acquiring its energy then? Locally, only a vector potential is present. How does the vector potential facilitate the formation of the current? Is the current formation a result of a truly non-local quantum action, or does the local action of the vector potential have experimental consequences? We discuss possible experiments with a hybrid normal-metal superconductor circuitry, which can clarify this puzzling situation. Experimental answers will be important for further developments.

  19. Fight against the greenhouse effect. From the local to the international action

    International Nuclear Information System (INIS)

    Mousel, M.

    2002-01-01

    In the fight against the greenhouse gases emissions, the local government are directly concerned. This sheet aims to explain the greenhouse effect, the kyoto protocol, the french national policy and to orientate the local actions. (A.L.B.)

  20. The Effects of Hearing Aids on Localization of White Noise by Blind Subjects.

    Science.gov (United States)

    Bergen, Bruce R.

    1980-01-01

    An investigation was conducted to observe the effects of hearing aids on the ability of 20 blind veterans to localize white noise. In all cases, Ss performed more poorly on a localization task while wearing a hearing aid. (Author)

  1. Local effects in flow-accelerated corrosion wall thinning

    International Nuclear Information System (INIS)

    Pietralik, J.

    2006-01-01

    'Full text:' There is enough evidence that flow conditions play the dominant role locally in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, which can be low or high, flow conditions determine the local distribution of wall thinning. This relationship is not new and recent accurate measurements of FAC rate of a plant feeder bend confirm that the relationship between flow local conditions expressed by local mass transfer coefficient and FAC rate in CANDU feeder bends is close. There is also a lot of other direct and indirect, experimental and laboratory evidence about this relationship. This knowledge can be useful for minimizing inspection, predicting new locations for inspection, predicting the location with the highest FAC rate for a given piping component, e.g., feeder element, and determining what components or feeders and to what extent they should be replaced. It applies also to heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local flow parameters. For FAC, the most important flow parameter is mass transfer coefficient. The mass transfer coefficient describes the intensity of the transport of corrosion products from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate. It could also be used in planning experiments because time-varying surface roughness can explain the time-dependence of FAC rates. The paper presents plant and laboratory evidence about the relationship. In addition, it shows correlations for mass transfer coefficient in components that are highly susceptible to FAC. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

  2. Practicing for space underwater: inventing neutral buoyancy training, 1963-1968.

    Science.gov (United States)

    Neufeld, Michael J; Charles, John B

    2015-01-01

    Neutral buoyancy's value was far from obvious when human spaceflight began in 1961. Starting in 1964, Environmental Research Associates, a tiny company in the suburbs of Baltimore, developed the key innovations in an obscure research project funded by NASA's Langley Research Center. The new Houston center dismissed it until a mid-1966 EVA crisis, after which it rapidly took over. In parallel, NASA Marshall Space Flight Center developed many of the same techniques, as did many large aerospace corporations, yet the long-run technological impact of corporate activity was near zero. Because ERA and Marshall's pioneering activities led to the two long-running NASA training centers at Houston and Huntsville, those two organizations deserve primary credit for the construction of the neutral buoyancy technological system. Published by Elsevier Ltd.

  3. Tropical cloud buoyancy is the same in a world with or without ice

    Science.gov (United States)

    Seeley, Jacob T.; Romps, David M.

    2016-04-01

    When convective clouds grow above the melting line, where temperatures fall below 0°C, condensed water begins to freeze and water vapor is deposited. These processes release the latent heat of fusion, which warms cloud air, and many previous studies have suggested that this heating from fusion increases cloud buoyancy in the upper troposphere. Here we use numerical simulations of radiative-convective equilibrium with and without ice processes to argue that tropical cloud buoyancy is not systematically higher in a world with fusion than in a world without it. This insensitivity results from the fact that the environmental temperature profile encountered by developing tropical clouds is itself determined by convection. We also offer a simple explanation for the large reservoir of convective available potential energy in the tropical upper troposphere that does not invoke ice.

  4. Numerical and Experimental Study on Negative Buoyance Induced Vortices in N-Butane Jet Flames

    KAUST Repository

    Xiong, Yuan

    2015-07-26

    Near nozzle flow field in flickering n-butane diffusion jet flames was investigated with a special focus on transient flow patterns of negative buoyance induced vortices. The flow structures were obtained through Mie scattering imaging with seed particles in a fuel stream using continuous-wave (CW) Argon-ion laser. Velocity fields were also quantified with particle mage velocimetry (PIV) system having kHz repetition rate. The results showed that the dynamic motion of negative buoyance induced vortices near the nozzle exit was coupled strongly with a flame flickering instability. Typically during the flame flickering, the negative buoyant vortices oscillated at the flickering frequency. The vortices were distorted by the flickering motion and exhibited complicated transient vortical patterns, such as tilting and stretching. Numerical simulations were also implemented based on an open source C++ package, LaminarSMOKE, for further validations.

  5. Neutral buoyancy testing of architectural and environmental concepts of space vehicle design

    Science.gov (United States)

    Lenda, J. A.; Rosener, A. A.; Stephenson, M. L.

    1972-01-01

    Design guidelines are presented that are applicable to providing habitability areas and furniture elements for extended periods in a zero gravity environment. This was accomplished by: (1) analyzing the existing habitability crew area requirements, mobility and restraint aids, cross-cultural design, and establishing a man model for zero gravity; (2) designing specific furniture elements, chair and table, and volumes for a stateroom, office, bathroom, galley, and wardroom; and (3) neutral buoyancy testing and evaluation of these areas.

  6. Experimental Study of Wind-Opposed Buoyancy-Driven Natural Ventilation

    OpenAIRE

    Andersen, A.; Bjerre, M.; Chen, Z. D.; Heiselberg, Per; Li, Y.

    2000-01-01

    Natural ventilation driven by natural forces, i.e. wind and thermal buoyancy, is an environmentally friendly system for buildings and has been increasingly used around the world in recent years to mitigate the impact on the global environment due to the significant energy consumption by heating, ventilation and air-conditioning (HV AC). There is a need for the understanding and development of theories and tools related to the design, operation and control of natural ventilation systems.

  7. Statistical Change Detection for Diagnosis of Buoyancy Element Defects on Moored Floating Vessels

    DEFF Research Database (Denmark)

    Blanke, Mogens; Fang, Shaoji; Galeazzi, Roberto

    2012-01-01

    . After residual generation, statistical change detection scheme is derived from mathematical models supported by experimental data. To experimentally verify loss of an underwater buoyancy element, an underwater line breaker is designed to create realistic replication of abrupt faults. The paper analyses...... the properties of residuals and suggests a dedicated GLRT change detector based on a vector residual. Special attention is paid to threshold selection for non ideal (non-IID) test statistics....

  8. Experimental Study of Wind-Opposed Buoyancy-Driven Natural Ventilation

    DEFF Research Database (Denmark)

    Andersen, A.; Bjerre, M.; Chen, Z. D.

    Natural ventilation driven by natural forces, i.e. wind and thermal buoyancy, is an environmentally friendly system for buildings and has been increasingly used around the world in recent years to mitigate the impact on the global environment due to the significant energy consumption by heating......, ventilation and air-conditioning (HV AC). There is a need for the understanding and development of theories and tools related to the design, operation and control of natural ventilation systems....

  9. Global and local Joule heating effects seen by DE 2

    Science.gov (United States)

    Heelis, R. A.; Coley, W. R.

    1988-01-01

    In the altitude region between 350 and 550 km, variations in the ion temperature principally reflect similar variations in the local frictional heating produced by a velocity difference between the ions and the neutrals. Here, the distribution of the ion temperature in this altitude region is shown, and its attributes in relation to previous work on local Joule heating rates are discussed. In addition to the ion temperature, instrumentation on the DE 2 satellite also provides a measure of the ion velocity vector representative of the total electric field. From this information, the local Joule heating rate is derived. From an estimate of the height-integrated Pedersen conductivity it is also possible to estimate the global (height-integrated) Joule heating rate. Here, the differences and relationships between these various parameters are described.

  10. The effect of faulty local detectors on a detection network

    International Nuclear Information System (INIS)

    Mirjalily, G.; Emadi, S.

    2002-01-01

    Distributed detection theory has received increasing attention recently. Development of multiple sensors for signal detection results in improved performance and increased reliability. in a detection network, each local sensor decides locally whether a signal is detected or not. The local decisions are sent to the fusion center, where the final decision is made. In this paper, a theoretic approach is considered to data fusion when one of the sensors is faulty. If the fusion center does not have any knowledge of this fault, the performance of the system is different than its normal performance. The changes in the error probabilities depend on the type of the fault and on the threshold value of the fission center test. We derived some expressions of the changes in the values of error probabilities. For some type of faults, the system false alarm probability increases significantly, whereas for some other faults, the system detection probability decreases significantly. To illustrate the results, a numerical example is also given

  11. Effects of large-scale deforestation on precipitation in the monsoon regions: remote versus local effects.

    Science.gov (United States)

    Devaraju, N; Bala, Govindasamy; Modak, Angshuman

    2015-03-17

    In this paper, using idealized climate model simulations, we investigate the biogeophysical effects of large-scale deforestation on monsoon regions. We find that the remote forcing from large-scale deforestation in the northern middle and high latitudes shifts the Intertropical Convergence Zone southward. This results in a significant decrease in precipitation in the Northern Hemisphere monsoon regions (East Asia, North America, North Africa, and South Asia) and moderate precipitation increases in the Southern Hemisphere monsoon regions (South Africa, South America, and Australia). The magnitude of the monsoonal precipitation changes depends on the location of deforestation, with remote effects showing a larger influence than local effects. The South Asian Monsoon region is affected the most, with 18% decline in precipitation over India. Our results indicate that any comprehensive assessment of afforestation/reforestation as climate change mitigation strategies should carefully evaluate the remote effects on monsoonal precipitation alongside the large local impacts on temperatures.

  12. Eddy-Kuroshio Interactions: Local and Remote Effects

    Science.gov (United States)

    Jan, Sen; Mensah, Vigan; Andres, Magdalena; Chang, Ming-Huei; Yang, Yiing Jang

    2017-12-01

    western North Pacific, is important in redistributing ocean energy and, in turn, shaping the large scale ocean circulation. This study focuses on the processes underlying the interaction of nonlinear mesoscale eddies with the Kuroshio, which have not yet been thoroughly investigated in the literature. Using pressure-sensor equipped echo sounder and satellite observations interpreted in the context of semi-idealized numerical simulations, this study find (1) locally, eddy arrivals modify velocity structure in the Kuroshio first, followed by changes in sea level and isopycnal depths leading to seesaw-like variations of the sea level and density slopes across the Kuroshio, and (2) modeled remote effects, i.e., Kuroshio intrusions, manifest in the Luzon Strait and on the East China Sea shelf and depend on the eddies' impingement latitude, strength, and polarity.

  13. Modeling Local Monetary Flows in Poor Regions: A Research Setup to Simulate the Multiplier Effect in Local Economies

    Directory of Open Access Journals (Sweden)

    Henk van Arkel

    2007-10-01

    Full Text Available In poor regions, lack of local monetary circulation is one of the key elements causing underdevelopment. The more incoming money is passed from hand to hand, the more the local economy will be stimulated. However, in most poor areas money is spent outside the community before circulating locally, reducing the effectiveness of money inflow dramatically.Development programs would increase their effectiveness if knowledge was available on how spending money could lead to optimized and prolonged local circulation. To gain this knowledge a simulation tool will be created, which is able to analyze financial flows, to evaluate the potency of specific actions aimed on local development, and to monitor a development scheme during the execution phase.The basic model will be developed through a multi-agent approach, where each agent represents one (or more family/households belonging to one of several socio-economic groups. A Social Accounting Matrix (SAM of the local economy will be used as a basis to set up a spendings matrix for each agent, defining its spending priorities. Artificial Intelligence techniques will be used to give the agent the possibility to make decisions on how to satisfy these spending priorities. Also, social dynamics, the simulation of strategic planning behavior, learning, and exchange in limited networks will be addressed.The simulation application will consist of a common user interface allowing the user to “play” the simulation. This user interface layer will be “pluggable” with the underlying programming layer responsible for the calculations on the simulation, so that different plug-ins may be used for different simulation techniques.

  14. Buoyancy-driven mean flow in a long channel with a hydraulically constrained exit condition

    Science.gov (United States)

    Grimm, Th.; Maxworthy, T.

    1999-11-01

    Convection plays a major role in a variety of natural hydrodynamic systems. Those in which convection drives exchange flows through a lateral contraction and/or over a sill form a special class with typical examples being the Red and Mediterranean Seas, the Persian Gulf, and the fjords that indent many coastlines. The present work focuses on the spatial distribution and scaling of the density difference between the inflowing and outflowing fluid layers. Using a long water-filled channel, fitted with buoyancy sources at its upper surface, experiments were conducted to investigate the influence of the geometry of the strait and the channel as well as the magnitude of the buoyancy flux. Two different scaling laws, one by Phillips (1966), and one by Maxworthy (1994, 1997) were compared with the experimental results. It has been shown that a scaling law for which g[prime prime or minute] = kB02/3x/h4/3 best describes the distribution of the observed density difference along the channel, where B0 is the buoyancy flux, x the distance from the closed end of the channel, h its height at the open end (sill) and k a constant that depends on the details of the channel geometry and flow conditions. This result holds for the experimental results and appears to be valid for a number of natural systems as well.

  15. Two-phase turbulent mixing and buoyancy drift in rod bundles

    International Nuclear Information System (INIS)

    Carlucci, L.N.; Hammouda, N.; Rowe, D.S.

    2004-01-01

    This paper describes the development of generalized relationships for single- and two-phase inter subchannel turbulent mixing in vertical and horizontal flows, and lateral buoyancy drift in horizontal flows. The relationships for turbulent mixing, together with a recommended one for void drift, have been implemented in a subchannel thermal hydraulics code, and assessed using a range of data on enthalpy migration in vertical steam-water lows under BWR and PWR diabatic conditions. The intent of this assessment as to optimize these relationships to give the best agreement with the enthalpy migration data for vertical flows. The optimized turbulent mixing relationships were then used as a basis to benchmark a proposed buoyancy rift model to give the best predictions of void and enthalpy migration data n horizontal flows typical of PHWR CANDU reactor operation under normal and off-normal conditions. Overall, the optimized turbulent mixing and buoyancy drift relationships have been found to predict the available data quite well, nd generally better and more consistently than currently used models. This is expected to result in more accurate calculations of subchannel distributions of phasic flows, and hence, in improved predictions of critical heat flux (CHF)

  16. Influence of radiation on predictive accuracy in numerical simulations of the thermal environment in industrial buildings with buoyancy-driven natural ventilation

    International Nuclear Information System (INIS)

    Meng, Xiaojing; Wang, Yi; Liu, Tiening; Xing, Xiao; Cao, Yingxue; Zhao, Jiangping

    2016-01-01

    Highlights: • The effects of radiation on predictive accuracy in numerical simulations were studied. • A scaled experimental model with a high-temperature heat source was set up. • Simulation results were discussed considering with and without radiation model. • The buoyancy force and the ventilation rate were investigated. - Abstract: This paper investigates the effects of radiation on predictive accuracy in the numerical simulations of industrial buildings. A scaled experimental model with a high-temperature heat source is set up and the buoyancy-driven natural ventilation performance is presented. Besides predicting ventilation performance in an industrial building, the scaled model in this paper is also used to generate data to validate the numerical simulations. The simulation results show good agreement with the experiment data. The effects of radiation on predictive accuracy in the numerical simulations are studied for both pure convection model and combined convection and radiation model. Detailed results are discussed regarding the temperature and velocity distribution, the buoyancy force and the ventilation rate. The temperature and velocity distributions through the middle plane are presented for the pure convection model and the combined convection and radiation model. It is observed that the overall temperature and velocity magnitude predicted by the simulations for pure convection were significantly greater than those for the combined convection and radiation model. In addition, the Grashof number and the ventilation rate are investigated. The results show that the Grashof number and the ventilation rate are greater for the pure convection model than for the combined convection and radiation model.

  17. Effect of processing (sprouting and fermentation) of five local ...

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    protein digestibility and mineral element composition of five local varieties were studied. ... Processed sorghum seeds or flour were found to be important sources of ... digestible than the proteins of other similar cooked cereals such as wheat and ... covered and kept for 72 hours away from light for fermentation to occur.

  18. Effects of surprisal and locality on Danish sentence processing

    DEFF Research Database (Denmark)

    Balling, Laura Winther; Kizach, Johannes

    2017-01-01

    An eye-tracking experiment in Danish investigates two dominant accounts of sentence processing: locality-based theories that predict a processing advantage for sentences where the distance between the major syntactic heads is minimized, and the surprisal theory which predicts that processing time...

  19. Local socio-economic effects of protected area conservation: The ...

    African Journals Online (AJOL)

    Some villagers have benefited from pilot development projects organized by financial and environmental organizations. Other local people benefited from other livelihood activities related to the conservation management of the forest. Most participants were aware of the ecosystem services of the forests (94.3%) and the ...

  20. Conversion to biofuel based heating systems - local environmental effects

    International Nuclear Information System (INIS)

    Jonsson, Anna

    2003-01-01

    One of the most serious environmental problems today is the global warming, i.e.climate changes caused by emissions of greenhouse gases. The greenhouse gases originate from combustion of fossil fuels and changes the atmospheric composition. As a result of the climate change, the Swedish government has decided to make a changeover of the Swedish energy system. This involves an increase of the supply of electricity and heating from renewable energy sources and a decrease in the amount electricity used for heating, as well as a more efficient use of the existing electricity system. Today, a rather large amount electricity is used for heating in Sweden. Furthermore, nuclear power will be phased out by the year 2010 in Sweden. Bio fuels are a renewable energy source and a conceivable alternative to the use of fossil fuels. Therefore, an increase of bio fuels will be seen the coming years. Bio fuels have a lot of environmental advantages, mainly for the global environment, but might also cause negative impacts such as depletion of the soils where the biomass is grown and local deterioration of the air quality where the bio fuels are combusted. These negative impacts are a result of the use of wrong techniques and a lack of knowledge and these factors have to be improved if the increase of the use of bio fuels is to be made effectively. The aim of this master thesis is to evaluate the possibilities for heating with bio fuel based systems in housing areas in the municipalities of Trollhaettan, Ulricehamn and Goetene in Vaestra Goetalands County in the South West of Sweden and to investigate which environmental and health effects are caused by the conversion of heating systems. The objective is to use the case studies as examples on preferable bio fuel based heating systems in different areas, and to what environmental impact this conversion of heating systems might cause. The housing areas for this study have been chosen on the basis of present heating system, one area

  1. Breakdown of local information processing may underlie isoflurane anesthesia effects.

    Science.gov (United States)

    Wollstadt, Patricia; Sellers, Kristin K; Rudelt, Lucas; Priesemann, Viola; Hutt, Axel; Fröhlich, Flavio; Wibral, Michael

    2017-06-01

    The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source-such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)-as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy-suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in information

  2. Analysis of Understanding the Concept of Buoyancy in the Context of its Transfer from Pre-school Teachers to Children

    Directory of Open Access Journals (Sweden)

    Petra Furlan

    2014-03-01

    Full Text Available Kindergarten curricula (Bahovec et al. 1999, 37 cover different areas of education that are sensibly interconnected and integrated. Science is one of the areas that represent child’s first learning about the surrounding world and the first introduction to nature. Science education is a very suitable approach of introducing children into basic research work, since in nature objects and phenomena are more concrete, and hence the children are instinctively attracted. Therefore, science education could act as a starting point for all other areas of education. Teaching science comprises several difficulties, which are mainly connected with the way how contents are introduced to children. This is often a great challenge and great responsibility for pre-school teachers, because the scientific content needs to be explained in an appropriate way taking into consideration the child's age, the use of correct terminology, and at the same time avoiding inadequate generalization and over-simplification. Buoyancy is a natural phenomenon that is experienced by every child, but which, on the other hand, is quite difficult to explain. With the present study we wished to assess the knowledge considering buoyancy of the part-time students within the Pre-school Teaching educational programme at the Faculty of Education of the University of Primorska, which is performed on different locations throughout Slovenia. These students already teach in the kindergartens and should be well acquainted with buoyancy from previously passed physics courses at the Faculty of Education. We examined how they explained the buoyancy to children in kindergartens, and whether the knowledge about buoyancy is affected by their working experience or the location of their study. The results show that the students’ knowledge about buoyancy is insufficient and incomplete. In addition, many misconceptions about buoyancy are transmitted to the children in the process of teaching

  3. Buoyancy under control: underwater locomotor performance in a deep diving seabird suggests respiratory strategies for reducing foraging effort.

    Directory of Open Access Journals (Sweden)

    Timothée R Cook

    Full Text Available BACKGROUND: Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag and report locomotor adjustments to the change of buoyancy with depth. METHODOLOGY/PRINCIPAL FINDINGS: Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with. CONCLUSIONS/SIGNIFICANCE: Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants--as in other families of diving seabirds--of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control.

  4. Quantitative localization microscopy: effects of photophysics and labeling stoichiometry.

    Directory of Open Access Journals (Sweden)

    Robert P J Nieuwenhuizen

    Full Text Available Quantification in localization microscopy with reversibly switchable fluorophores is severely hampered by the unknown number of switching cycles a fluorophore undergoes and the unknown stoichiometry of fluorophores on a marker such as an antibody. We overcome this problem by measuring the average number of localizations per fluorophore, or generally per fluorescently labeled site from the build-up of spatial image correlation during acquisition. To this end we employ a model for the interplay between the statistics of activation, bleaching, and labeling stoichiometry. We validated our method using single fluorophore labeled DNA oligomers and multiple-labeled neutravidin tetramers where we find a counting error of less than 17% without any calibration of transition rates. Furthermore, we demonstrated our quantification method on nanobody- and antibody-labeled biological specimens.

  5. Effect of antigen on localization of immunologically specific B cells

    International Nuclear Information System (INIS)

    Ponzio, N.M.; Chapman, J.M.; Thorbecke, G.J.

    1976-01-01

    Studies were conducted to demonstrate homing of memory B cells to sites of antigen localization in lymph nodes, using functional criteria to detect local presence of memory cells at varying intervals after intravenous injection. Cell suspensions were prepared from spleens of donor mice injected with complete Freund's adjuvant. Recipient mice were injected with Escherichia coli endotoxin and immune or normal spleen cells and were gamma-irradiated. Results indicated that passively transferred unilateral B cell memory was established. The development over a period of several days of this difference between left and right lymph nodes suggests that recirculating memory B cells are being progressively selected by antigen in the lymph node, rather than that this difference is due to a specific exit of cells from the circulation towards the antigen

  6. The Effectiveness of Social Media Implementation at Local Government Levels

    Directory of Open Access Journals (Sweden)

    Elvira NICA

    2014-12-01

    Full Text Available The purpose of this article is to gain a deeper understanding of the management of social me-dia at the local government level, the availability of opportunities for citizen dialogue on govern-ment websites, and the impact that social net-working applications have on e-government. The results of the current study converge with prior research on the growing awareness amongst government practitioners regarding the relevance of social media, the use of social media for feed-back on service quality, and privacy and security commitments in e-government. The literature on the use of information technology to transform government, the potential for online government information to contribute to citizen engagement, and the rapid growth in local government use of social media is relevant to this discussion.

  7. Modeling the effects of local climate change on crop acreage

    Directory of Open Access Journals (Sweden)

    Hyunok Lee

    2016-01-01

    Full Text Available The impacts of climate change on agriculture depend on local conditions and crops grown. For instance, warmer winter temperatures in a given area would reduce chill hours, potentially cutting yields for some crops but extending the growing season for others. Using a century of climate data and six decades of acreage data, we established quantitative economic relationships between the evolution of local climate and acreage of 12 important crops in Yolo County. We then used the historical trend in climate change to project future crop acreages in the county. Only marginal changes in acreage in 2050 were projected for tree and vine crops there, in part because chill hours, although lower, remained above critical values. Walnuts were the most vulnerable tree crop, and the projections indicated some cultivars might be marginal in years with particularly warm winters. Processing tomato acreage might increase, due to a longer growing season, and also alfalfa acreage, if water availability and other factors remain constant.

  8. Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

    Science.gov (United States)

    Freeburg, Eric Thomas

    Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed

  9. Localization effects in rare earth high Tc superconductors

    International Nuclear Information System (INIS)

    Badera, Nitu; Godbole, Bhavana; Srivastava, S.B.; Rathore, M.K.; Ganesa, V.

    2006-01-01

    The Y 1-x Gd x Ba 2 Cu 3 O 7-δ samples have been prepared for different concentration of Gd . We employ thermoelectric power technique, which is sensitive to changes at the Fermi surface to study these materials. Metallic diffusion model and two band model are used to evaluate the normal state properties of these materials. At concentrations above 5% clear wide linear regions have been observed suggesting good evidence for localized states. (author)

  10. Buoyancy-Driven Ventilation Generated by the Double-Skin Façade of a High-Rise Building in Tropical Climate: Case Study Bandung, Indonesia

    Directory of Open Access Journals (Sweden)

    Aziiz Akhlish Diinal

    2017-01-01

    Full Text Available High-rise buildings in tropical region is identical to the use of mechanical Air Conditioning in massive scale. Nevertheless, there is an encouragement to high-rise buildings to reduce its energy consumptions, since they consume quite large amount of energy. This challenge can be overcome with various of strategies, one of them, by means of reducing the cooling load of mechanical Air Conditioning in high-rise building. Prospects come from the modern tall building design strategies, for example the use of double-skin façade to give addition of building skin which could provide indoor temperature protection from outside. Double-skin façade system has continued to increase in buildings in a tropical region such as in Indonesia. However, there is another potential of double skin façade, which is the possibility to increase the buoyancy effect in the air gap between the skin and building envelope. The possibility needs to be studied in order to give a proper way in designing double-skin façade of a high-rise building, especially on Bandung-Indonesia tropical climate. This paper explores the potential of double-skin façade in driving the air inside the façade to generate natural ventilation for a high-rise building in Bandung climate condition. Two parameters are used in exploring the buoyancy force, the width of double-skin façade and the temperature of the skin façade. In general, double-skin façade of a high-rise building in tropical climate can generate buoyancy driven ventilation for the building, it relates strongly to the distance between of the double-skin façade and the building envelope.

  11. Avalanche localization and its effects in proportional counters

    International Nuclear Information System (INIS)

    Fischer, J.; Okuno, H.; Walenta, A.H.

    1977-11-01

    Avalanche development around the anode wire in a gas proportional counter is investigated. In the region of proportional gas amplification, the avalanche is found to be well localized on one side of the anode wire, where the electrons arrive along the field lines from the point of primary ionization. Induced signals on electrodes surrounding the anode wire are used to measure the azimuthal position of the avalanche on the anode wire. Practical applications of the phenomena such as left-right assignment in drift chambers and measurement of the angular direction of the primary ionization electrons drifting towards the anode wire are discussed

  12. Estimating Causal Effects of Local Air Pollution on Daily Deaths: Effect of Low Levels.

    Science.gov (United States)

    Schwartz, Joel; Bind, Marie-Abele; Koutrakis, Petros

    2017-01-01

    , Koutrakis P. 2017. Estimating causal effects of local air pollution on daily deaths: effect of low levels. Environ Health Perspect 125:23-29; http://dx.doi.org/10.1289/EHP232.

  13. Localized hole effects in inner-shell excitation

    International Nuclear Information System (INIS)

    Rescigno, T.N.; Orel, A.E.

    1983-01-01

    Ab initio calculations of valence shell ionization potentials have shown that orbital relaxation and correlation differences usually make contributions of comparable magnitude. In marked contrast to this observation is the situation for deep core ionization, where correlation differences (approx. 1 eV) play a relatively minor role compared to orbital relaxation (approx. 20 eV). Theoretical calculations have shown that this relaxation is most easily described if the 1s-vacancy created by a K-shell excitation is allowed to localize on one of the atomic centers. For molecules possessing a center of inversion, this means that the molecular orbitals that best describe the final state do not transform as any irreducible representation of the molecular point group. Recent experimental work by Shaw, King, Read and Cvejanovic and by Stefani and coworkers has prompted us to carry out further calculations on N 2 , as well as analogous investigations of 1s/sub N/ → π* excitation in NO and N 2 O. The generalized oscillator strengths display a striking similarity and point to the essential correctness of the localized hole picture for N 2 . The theoretical calculations are briefly described, followed by a summary of the results and comparison to experiment, followed by a short discussion

  14. Cost-Effectiveness of a Locally Organized Surgical Outreach Mission: Making a Case for Strengthening Local Non-Governmental Organizations.

    Science.gov (United States)

    Gyedu, Adam; Gaskill, Cameron; Boakye, Godfred; Abantanga, Francis

    2017-12-01

    Many low- and middle-income countries (LMICs) have a high prevalence of unmet surgical need. Provision of operations through surgical outreach missions, mostly led by foreign organizations, offers a way to address the problem. We sought to assess the cost-effectiveness of surgical outreach missions provided by a wholly local organization in Ghana to highlight the role local groups might play in reducing the unmet surgical need of their communities. We calculated the disability-adjusted life years (DALY) averted by surgical outreach mission activities of ApriDec Medical Outreach Group (AMOG), a Ghanaian non-governmental organization. The total cost of their activities was also calculated. Conclusions about cost-effectiveness were made according to World Health Organization (WHO)-suggested parameters. We analyzed 2008 patients who had been operated upon by AMOG since December 2011. Operations performed included hernia repairs (824 patients, 41%) and excision biopsy of soft tissue masses (364 patients, 18%). More specialized operations included thyroidectomy (103 patients, 5.1%), urological procedures (including prostatectomy) (71 patients, 3.5%), and plastic surgery (26 patients, 1.3%). Total cost of the outreach trips was $283,762, and 2079 DALY were averted; cost per DALY averted was 136.49 USD. The mission trips were "very cost-effective" per WHO parameters. There was a trend toward a lower cost per DALY averted with subsequent outreach trips organized by AMOG. Our findings suggest that providing surgical services through wholly local surgical mission trips to underserved LMIC communities might represent a cost-effective and viable option for countries seeking to reduce the growing unmet surgical needs of their populations.

  15. Effect of localized hypoxia on Drosophila embryo development.

    Directory of Open Access Journals (Sweden)

    Zhinan Wang

    Full Text Available Environmental stress, such as oxygen deprivation, affects various cellular activities and developmental processes. In this study, we directly investigated Drosophila embryo development in vivo while cultured on a microfluidic device, which imposed an oxygen gradient on the developing embryos. The designed microfluidic device enabled both temporal and spatial control of the local oxygen gradient applied to the live embryos. Time-lapse live cell imaging was used to monitor the morphology and cellular migration patterns as embryos were placed in various geometries relative to the oxygen gradient. Results show that pole cell movement and tail retraction during Drosophila embryogenesis are highly sensitive to oxygen concentrations. Through modeling, we also estimated the oxygen permeability across the Drosophila embryonic layers for the first time using parameters measured on our oxygen control device.

  16. Crack propagation model taking into consideration the local effect of the deviatoric stress and the non-local effect of the isotropic stress

    Czech Academy of Sciences Publication Activity Database

    Kafka, Vratislav

    2011-01-01

    Roč. 56, č. 4 (2011), s. 343-358 ISSN 0001-7043 R&D Projects: GA ČR(CZ) GA103/09/2101 Institutional research plan: CEZ:AV0Z20710524 Keywords : crack propagation * nonlocal effect * deviatoric local effect * isotropic nonlocal Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Effects of muscle injury severity on localized bioimpedance measurements

    International Nuclear Information System (INIS)

    Nescolarde, L; Rosell-Ferrer, J; Yanguas, J; Lukaski, H; Alomar, X; Rodas, G

    2015-01-01

    Muscle injuries in the lower limb are common among professional football players. Classification is made according to severity and is diagnosed with radiological assessment as: grade I (minor strain or minor injury), grade II (partial rupture, moderate injury) and grade III (complete rupture, severe injury). Tetrapolar localized bioimpedance analysis (BIA) at 50 kHz made with a phase-sensitive analyzer was used to assess damage to the integrity of muscle structures and the fluid accumulation 24 h after injury in 21 injuries in the quadriceps, hamstring and calf, and was diagnosed with magnetic resonance imaging (MRI). The aim of this study was to identify the pattern of change in BIA variables as indicators of fluid [resistance (R)] and cell structure integrity [reactance (Xc) and phase angle (PA)] according to the severity of the MRI-defined injury. The % difference compared to the non-injured contralateral muscle also measured 24-h after injury of R, Xc and PA were respectively: grade I (n = 11; −10.4, −17.5 and −9.0%), grade II (n = 8; −18.4, −32.9 and −16.6%) and grade III (n = 2; −14.1, −52.9 and −43.1%), showing a greater significant decrease in Xc (p < 0.001). The greatest relative changes were in grade III injuries. However, decreases in R, that indicate fluid distribution, were not proportional to the severity of the injury. Disruption of the muscle structure, demonstrated by the localized determination of Xc, increased with the severity of muscle injury. The most significant changes 24 h after injury was the sizeable decrease in Xc that indicates a pattern of disrupted soft tissue structure, proportional to the severity of the injury. (paper)

  18. Influence of the variable thermophysical properties on the turbulent buoyancy-driven airflow inside open square cavities

    Science.gov (United States)

    Zamora, Blas; Kaiser, Antonio S.

    2012-01-01

    The effects of the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated, as well as the influence of the stated boundary conditions at open edges and the employed differencing scheme. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low-Reynolds k - ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide and not yet covered range of the Rayleigh number varying from 103 to 1016. The results obtained taking into account variable properties effects are compared with those calculated assuming constant properties and the Boussinesq approximation. For uniform heat flux heating, a correlation for the critical heating parameter above which the burnout phenomenon can be obtained is presented, not reported in previous works. The effects of variable properties on the flow patterns are analyzed.

  19. Optimizing Local Plant Products in Building Construction:Effects of ...

    African Journals Online (AJOL)

    ... and on bamboo reinforced concrete beams reveal that indeed truss configuration has marked effect on the stiffness and ultimate strength of trusses, where vertically aligned members as found in queen-post and Howe trusses are seen to be more effective than inclined members in load transfer and ultimate resistance.

  20. Commuter Effects on Local Labour Markets: A German Modelling Study

    NARCIS (Netherlands)

    Russo, G.; Tedeschi, F.; Reggiani, A.; Nijkamp, P.

    2014-01-01

    This paper offers an exploratory investigation of the effects of inbound commuter flows on employment in regional labour markets in Germany. For this purpose, the paper distinguishes three main channels that may transmit the effects concerned: a crowding-out mechanism and two labour demand

  1. The effects of the local environment on active galactic nuclei

    International Nuclear Information System (INIS)

    Manzer, L. H.; De Robertis, M. M.

    2014-01-01

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 ≤ N ≤ 20) with redshifts between 0.01 and 0.20 are from the Sloan Digital Sky Survey. We first investigate the completeness of our data set and find, though biases are a concern particularly at higher redshift, that our data provide a fair representation of the local universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems

  2. The effects of the local environment on active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Manzer, L. H.; De Robertis, M. M., E-mail: liannemanzer@gmail.com, E-mail: mmdr@yorku.ca [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada)

    2014-06-20

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 ≤ N ≤ 20) with redshifts between 0.01 and 0.20 are from the Sloan Digital Sky Survey. We first investigate the completeness of our data set and find, though biases are a concern particularly at higher redshift, that our data provide a fair representation of the local universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems

  3. Surface effects on static bending of nanowires based on non-local elasticity theory

    Directory of Open Access Journals (Sweden)

    Quan Wu

    2015-10-01

    Full Text Available The surface elasticity and non-local elasticity effects on the elastic behavior of statically bent nanowires are investigated in the present investigation. Explicit solutions are presented to evaluate the surface stress and non-local elasticity effects with various boundary conditions. Compared with the classical Euler beam, a nanowire with surface stress and/or non-local elasticity can be either stiffer or less stiff, depending on the boundary conditions. The concept of surface non-local elasticity was proposed and its physical interpretation discussed to explain the combined effect of surface elasticity and non-local elasticity. The effect of the nanowire size on its elastic bending behavior was investigated. The results obtained herein are helpful to characterize mechanical properties of nanowires and aid nanowire-based devices design.

  4. The impact of pressure-dependent interfacial tension and buoyancy forces upon pressure depletion in virgin hydrocarbon reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, S.R.; Mackay, E.J. [Heriot-Watt University, Edinburgh (United Kingdom). Dept. of Petroleum Engineering

    1998-07-01

    This paper describes a combined experimental and theoretical study of the microscopic pore-scale physics characterizing gas and liquid production from hydrocarbon reservoirs during pressure depletion. The primary focus of the study was to examine the complex interactions between interfacial tension and buoyancy forces during gas evolution within a porous medium containing oil, water and gas. A specialized 2-dimensional glass micromodel, capable of operating at pressure in excess of 35 MPa was used to visualize the physical mechanisms governing such microscopic processes. In addition, a 3-dimensional, 3-phase numerical pore-scale simulator was developed that can be used to examine gas evolution over a range of different lengthscales and for a wide range of fluid and rock properties. The model incorporates all of the important physics observed in associated laboratory micromodel experiments, including: embryonic nucleation, supersaturation effects, multiphase diffusion, bubble growth-migration-fragmentation, and three-phase spreading coefficients. The precise pore-scale mechanisms governing gas evolution were found to be far more subtle than earlier models would suggest because of the large variation of gas/oil interfacial tension with pressure. This has a profound effect upon the migration of gas structures during depletion and, in models pertaining to reservoir rock, the process of gas migration is consequently much slower than previously thought. This is the first time that such a phenomena has been modelled at the pore-scale and the implications for production forecasting are thought to be significant. (author)

  5. Effects of Spatial Localization on Microbial Consortia Growth.

    Directory of Open Access Journals (Sweden)

    Michael Venters

    Full Text Available Microbial consortia are commonly observed in natural and synthetic systems, and these consortia frequently result in higher biomass production relative to monocultures. The focus here is on the impact of initial spatial localization and substrate diffusivity on the growth of a model microbial consortium consisting of a producer strain that consumes glucose and produces acetate and a scavenger strain that consumes the acetate. The mathematical model is based on an individual cell model where growth is described by Monod kinetics, and substrate transport is described by a continuum-based, non-equilibrium reaction-diffusion model where convective transport is negligible (e.g., in a biofilm. The first set of results focus on a single producer cell at the center of the domain and surrounded by an initial population of scavenger cells. The impact of the initial population density and substrate diffusivity is examined. A transition is observed from the highest initial density resulting in the greatest cell growth to cell growth being independent of initial density. A high initial density minimizes diffusive transport time and is typically expected to result in the highest growth, but this expected behavior is not predicted in environments with lower diffusivity or larger length scales. When the producer cells are placed on the bottom of the domain with the scavenger cells above in a layered biofilm arrangement, a similar critical transition is observed. For the highest diffusivity values examined, a thin, dense initial scavenger layer is optimal for cell growth. However, for smaller diffusivity values, a thicker, less dense initial scavenger layer provides maximal growth. The overall conclusion is that high density clustering of members of a food chain is optimal under most common transport conditions, but under some slow transport conditions, high density clustering may not be optimal for microbial growth.

  6. The Effects of the Local Environment on Active Galactic Nuclei

    Science.gov (United States)

    Manzer, L. H.; De Robertis, M. M.

    2014-06-01

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems, unlike star-forming galaxies. These results provide some indication that the local environment does play a role in initiating activity in galactic nuclei, but it is by no means simple or straightforward.

  7. Evaluation of the effect of locally administered amitriptyline gel as adjunct to local anesthetics in irreversible pulpitis pain

    Directory of Open Access Journals (Sweden)

    Moghadamnia A

    2009-01-01

    Full Text Available Background: Amitriptyline is one of the most common tricyclic antidepressants, which binds to pain sensory nerve fibers close to the sodium channel; hence, it could interact to some degree with receptors of local anesthetics. This study was designed to assess the additional analgesic effects of 2% Amitriptyline local gel administration in irreversible pulpitis pain of the molars. Materials and Methods: This study was a randomized, double-blind clinical trial that was performed on 56 consented adult patients who did not receive enough analgesia after a lidocaine nerve block for their tooth pulpitis pain. Patients were treated with 0.2 ml of either 2% amitriptyline or placebo, which was directly injected into their mandibular molar pulp chamber after they had received two routine lidocaine injections. Patients were asked to score their pain as a mark on a 10-cm Visual Analogue Scale (VAS at different timepoints: 0 (just before gel administration, 1, 3, 5, 7, and 9 minutes after the treatments. Results: There was a 92.5% decrease in VAS scores of patients 9 minutes after amitriptyline administration compared to Time 0, while in the placebo group this difference was only 13.5%. Further, in the amitriptyline group, the VAS score at all timepoints was statistically different from Time 0 ( P < 0.01. The overall pain reduction and its trend was significantly higher in the amitriptyline group compared with the placebo group ( P < 0.001. Conclusion: Inter-pulp space administration of amitriptyline 2% gel for completing analgesia in irreversible pulpitis pain could be effective and useful as a conjunctive therapy to injections of local anesthetics.

  8. Effect of a New Local Anesthetic Buffering Device on Pain Reduction During Nerve Block lnjections

    Science.gov (United States)

    2014-07-10

    the anticipation of pain associated with dental care is a significant deterrent in seeking treatment. With the advent of modern local anesthesia ...eliminate pain from dental injection to include: application of topical anesthesia , tissue pressure/vibration, cold application, and buffering of the local ...anesthetic solution. In dentistry , the effect of buffering local anesthetic solutions was first studied by Gros and Laewen in 1910 and then by

  9. The small length scale effect for a non-local cantilever beam: a paradox solved.

    Science.gov (United States)

    Challamel, N; Wang, C M

    2008-08-27

    Non-local continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with microstructures or nanostructures. This paper presents some simplified non-local elastic beam models, for the bending analyses of small scale rods. Integral-type or gradient non-local models abandon the classical assumption of locality, and admit that stress depends not only on the strain value at that point but also on the strain values of all points on the body. There is a paradox still unresolved at this stage: some bending solutions of integral-based non-local elastic beams have been found to be identical to the classical (local) solution, i.e. the small scale effect is not present at all. One example is the Euler-Bernoulli cantilever nanobeam model with a point load which has application in microelectromechanical systems and nanoelectromechanical systems as an actuator. In this paper, it will be shown that this paradox may be overcome with a gradient elastic model as well as an integral non-local elastic model that is based on combining the local and the non-local curvatures in the constitutive elastic relation. The latter model comprises the classical gradient model and Eringen's integral model, and its application produces small length scale terms in the non-local elastic cantilever beam solution.

  10. Professional Bandwagons and Local Discursive Effects: Reporting the Literate Student.

    Science.gov (United States)

    Comber, Barbara

    Despite the considerable attention given to literacy assessment, there has been very little examination of one of the most common assessment and reporting practices; namely, the teacher written report card. What kinds of literate subjects are constructed in teachers' written assessments of students and what are the effects for different students?…

  11. Effect of Sprouting on invitro digestibility of some locally consumed ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    Functional properties of lipid seed oil. (Lupinus metabilis) proteins and protein concentration. Journal of Food Science. 47: 491-. 497. (Taugo, L.C., Donangelo, C.M., Taugo, N.M.F. and. Knudsen-Bach, K.E. (2000)). Effect of heat treatment on nutritional quality of germinated legume seed J. Agric. Food Chem. 48: 2082-.

  12. Importance of quantification of local site effects based on wave ...

    Indian Academy of Sciences (India)

    This paper presents the three most important aspects of seismic microzonation namely prediction of fundamental frequency (F0) of soil deposit, aggravation factor (aggravation factor is ... We recommend the use of analytical or numerical methods to predict such an important parameter based on wave propagation effects.

  13. Local Electric Field Effects on Rhodium-Porphyrin and NHC-Gold Catalysts

    Science.gov (United States)

    2015-01-05

    AFRL-OSR-VA-TR-2015-0023 (NII) - Local Electric Field Effects on Rhodium -Porphyrin and NHC-Gold Catalysts MATTHEW KANAN LELAND STANFORD JUNIOR UNIV...Effects on Rhodium -Porphyrin and NHC-Gold Catalysts Principal Investigator: Matthew W. Kanan Project Publications: 1. “An Electric Field–Induced Change...Stanford University Grant/Contract Title The full title of the funded effort. (NII)-Local Electric Field Effects on Rhodium -Porphyrin and NHC-Gold

  14. Effect of chlorphenesin on localized hemolysis in gel assay.

    Science.gov (United States)

    Fukui, G M; Berger, F M; Chandlee, G C; Goldenbaum, E G

    1968-10-01

    Chlorphenesin, a simple glycerol ether, when added to Jerne plates greatly reduced the number of hemolytic plaques. This effect appeared to be related to dose, and was clearly demonstrable with antibody-forming spleen cells from mice that had been immunized either with sheep red blood cells or with penicillin G conjugated with Keyhole limpet hemocyanin. Chlorphenesin did not affect the antigen, destroy complement, or interfere with the interaction of complement and the antigen-antibody complexes. Incubation of spleen cell suspensions with chlorphenesin prior to plating was more effective in reducing the number of plaques than was addition of the substance to the plates. It may act by reducing the ability of antibodies to react with antigens or by affecting the release of antibodies from the spleen cells.

  15. Modeling of Reverberation Effects for Radio Localization and Communications

    DEFF Research Database (Denmark)

    Steinböck, Gerhard

    2013-01-01

    a recently proposed approach, we transcribe these models to electromagnetics and validate them experimentally following a systematic procedure. These transcribed models provide accurate predictions of the delay power spectrum in a typical office environment. Furthermore, they can predict changes...... into a distance dependent model of the delay power spectrum, which we then validate experimentally. From this model we derive secondary models that predict the received power, the mean delay, the rms delay spread and the kurtosis versus distance. The behavior of the diffuse component versus distance in indoor...... environment is linked to reverberation effects analog to reverberation effects observed in room acoustics and electromagnetic reverberation chambers. Reverberation models of room acoustics relate the decay rate of the diffuse component to the room geometry and an average absorption coefficient. Following...

  16. Spanwise homogeneous buoyancy-drag model for Rayleigh-Taylor mixing and experimental evaluation

    International Nuclear Information System (INIS)

    Dimonte, Guy

    2000-01-01

    A buoyancy-drag model for Rayleigh-Taylor (RT) mixing is developed on the premise that the bubble and spike regions behave as distinct and spanwise homogeneous fluids. Then, mass conservation is applied accross the mixing zone to obtain their average mixture densities dynamically. These are used to explicitly calculate the inertia and buoyancy terms in the evolutionary equation. The only unknown parameter in the model is the Newtonian drag constant C∼2.5±0.6, which is determined from turbulent RT experiments over various Atwood numbers A and acceleration histories g(t). The bubble (i=2) and spike (i=1) amplitudes are found to obey the familiar h i =α i Agt 2 for a constant g and h i ∼t θ i for an impulsive g. For bubbles, both α 2 and θ 2 are insensitive to A. For the spikes, both α 1 and θ 1 increase as a power law with the density ratio. However, θ 1 is not universal because it depends on the initial value of h 1 /h 2 . (c) 2000 American Institute of Physics

  17. Numerical Study of the Buoyancy-Driven Flow in a Four-Electrode Rectangular Electrochemical Cell

    Science.gov (United States)

    Sun, Zhanyu; Agafonov, Vadim; Rice, Catherine; Bindler, Jacob

    2009-11-01

    Two-dimensional numerical simulation is done on the buoyancy-driven flow in a four-electrode rectangular electrochemical cell. Two kinds of electrode layouts, the anode-cathode-cathode-anode (ACCA) and the cathode-anode-anode-cathode (CAAC) layouts, are studied. In the ACCA layout, the two anodes are placed close to the channel outlets while the two cathodes are located between the two anodes. The CAAC layout can be converted from the ACCA layout by applying higher electric potential on the two middle electrodes. Density gradient was generated by the electrodic reaction I3^-+2e^- =3I^-. When the electrochemical cell is accelerated axially, buoyancy-driven flow occurs. In our model, electro-neutrality is assumed except at the electrodes. The Navier-Stokes equations with the Boussinesq approximation and the Nernst-Planck equations are employed to model the momentum and mass transports, respectively. It is found that under a given axial acceleration, the electrolyte density between the two middle electrodes determines the bulk flow through the electrochemical cell. The cathodic current difference is found to be able to measure the applied acceleration. Other important electro-hydrodynamic characteristics are also discussed.

  18. Noninvasive embryo assessment technique based on buoyancy and its association with embryo survival after cryopreservation.

    Science.gov (United States)

    Wessels, Cara; Penrose, Lindsay; Ahmad, Khaliq; Prien, Samuel

    2017-11-01

    Embryo cryopreservation offers many benefits by allowing genetic preservation, genetic screening, cost reduction, global embryo transport and single embryo transfer. However, freezing of embryos decreases embryo viability, as intracellular ice crystal formation often damages embryos. Success rates of frozen embryo transfer are expected to be 15-20% less than fresh embryo transfer. We have developed a noninvasive embryo assessment technique (NEAT) which enables us to predict embryo viability based on buoyancy. The purpose of this research was twofold. First was to determine if a NEAT, through a specific gravity device can detect embryo survival of cryopreservation. Second, it was to relate embryo buoyancy to embryo viability for establishing pregnancies in sheep. Blastocysts descent times were measured on one-hundred sixty-nine mice blastocysts before cryopreservation, according to standard protocol and post-thawing blastocysts descent times were measured again. There was a significant difference in blastocyst post-thaw descent times with NEAT in those blastocysts which demonstrated viability from those that did not (P embryos. Further studies on a larger scale commercial setting will evaluate the efficacy of NEAT. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Buoyancy limits on magnetic viscosity stress-law scalings in quasi stellar object accretion disk models

    International Nuclear Information System (INIS)

    Sakimoto, P.J.

    1985-01-01

    Quasi-Stellar Objects (QSOs) are apparently the excessively bright nuclei of distant galaxies. They are thought to be powered by accretion disks surrounding supermassive black holes: however, proof of this presumption is hampered by major uncertainties in the viscous stress necessary for accretion to occur. Models generally assume an and hoc stress law which scales the stress with the total pressure. Near the black hole, radiation pressure dominates gas pressure; scaling the stress with the radiation pressure results in disk models that are thermally unstable and optically thin. This dissertation shows that a radiation pressure scaling for the stress is not possible if the viscosity is due to turbulent magnetic Maxwell stresses. The argument is one of internal self-consistency. First, four model accretion disks that bound the reasonably expected ranges of viscous stress scalings and vertical structures are constructed. Magnetic flux tubes of various initial field strengths are then placed within these models, nd their buoyancy is modeled numerically. In disks using the radiation pressure stress law scaling, low opacities allow rapid heat flow into the flux tubes: the tubes are extremely buoyant, and magnetic fields strong enough to provide the required stress cannot be retained. If an alternative gas pressure scaling for the stress is assumed, then the disks are optically thick; flux tubes have corresponding lower buoyancy, and magnetic fields strong enough to provide the stress can be retained for dynamically significant time periods

  20. A Six-DOF Buoyancy Tank Microgravity Test Bed with Active Drag Compensation

    Science.gov (United States)

    Sun, Chong; Chen, Shiyu; Yuan, Jianping; Zhu, Zhanxia

    2017-10-01

    Ground experiment under microgravity is very essential because it can verify the space enabling technologies before applied in space missions. In this paper, a novel ground experiment system that can provide long duration, large scale and high microgravity level for the six degree of freedom (DOF) spacecraft trajectory tracking is presented. In which, the most gravity of the test body is balanced by the buoyancy, and the small residual gravity is offset by the electromagnetic force. Because the electromagnetic force on the test body can be adjusted in the electromagnetic system, it can significantly simplify the balancing process using the proposed microgravity test bed compared to the neutral buoyance system. Besides, a novel compensation control system based on the active disturbance rejection control (ADRC) method is developed to estimate and compensate the water resistance online, in order to improve the fidelity of the ground experiment. A six-DOF trajectory tracking in the microgravity system is applied to testify the efficiency of the proposed compensation controller, and the experimental simulation results are compared to that obtained using the classic proportional-integral-derivative (PID) method. The simulation results demonstrated that, for the six-DOF motion ground experiment, the microgravity level can reach to 5 × 10-4 g. And, because the water resistance has been estimated and compensated, the performance of the presented controller is much better than the PID controller. The presented ground microgravity system can be applied in on-orbit service and other related technologies in future.

  1. Maximum Neutral Buoyancy Depth of Juvenile Chinook Salmon: Implications for Survival during Hydroturbine Passage

    Energy Technology Data Exchange (ETDEWEB)

    Pflugrath, Brett D.; Brown, Richard S.; Carlson, Thomas J.

    2012-03-01

    This study investigated the maximum depth at which juvenile Chinook salmon Oncorhynchus tshawytscha can acclimate by attaining neutral buoyancy. Depth of neutral buoyancy is dependent upon the volume of gas within the swim bladder, which greatly influences the occurrence of injuries to fish passing through hydroturbines. We used two methods to obtain maximum swim bladder volumes that were transformed into depth estimations - the increased excess mass test (IEMT) and the swim bladder rupture test (SBRT). In the IEMT, weights were surgically added to the fishes exterior, requiring the fish to increase swim bladder volume in order to remain neutrally buoyant. SBRT entailed removing and artificially increasing swim bladder volume through decompression. From these tests, we estimate the maximum acclimation depth for juvenile Chinook salmon is a median of 6.7m (range = 4.6-11.6 m). These findings have important implications to survival estimates, studies using tags, hydropower operations, and survival of juvenile salmon that pass through large Kaplan turbines typical of those found within the Columbia and Snake River hydropower system.

  2. Level-set simulations of buoyancy-driven motion of single and multiple bubbles

    International Nuclear Information System (INIS)

    Balcázar, Néstor; Lehmkuhl, Oriol; Jofre, Lluís; Oliva, Assensi

    2015-01-01

    Highlights: • A conservative level-set method is validated and verified. • An extensive study of buoyancy-driven motion of single bubbles is performed. • The interactions of two spherical and ellipsoidal bubbles is studied. • The interaction of multiple bubbles is simulated in a vertical channel. - Abstract: This paper presents a numerical study of buoyancy-driven motion of single and multiple bubbles by means of the conservative level-set method. First, an extensive study of the hydrodynamics of single bubbles rising in a quiescent liquid is performed, including its shape, terminal velocity, drag coefficients and wake patterns. These results are validated against experimental and numerical data well established in the scientific literature. Then, a further study on the interaction of two spherical and ellipsoidal bubbles is performed for different orientation angles. Finally, the interaction of multiple bubbles is explored in a periodic vertical channel. The results show that the conservative level-set approach can be used for accurate modelling of bubble dynamics. Moreover, it is demonstrated that the present method is numerically stable for a wide range of Morton and Reynolds numbers.

  3. Dynamic pore network simulator for modelling buoyancy-driven migration during depressurisation of heavy-oil systems

    Energy Technology Data Exchange (ETDEWEB)

    Ezeuko, C.C.; McDougall, S.R. [Heriot-Watt Univ., Edinburgh (United Kingdom); Bondino, I. [Total E and P UK Ltd., London (United Kingdom); Hamon, G. [Total S.A., Paris (France)

    2008-10-15

    In an attempt to investigate the impact of gravitational forces on gas evolution during solution gas drive, a number of vertically-oriented heavy oil depletion experiments have been conducted. Some of the results of these studies suggest the occurrence of gas migration during these tests. However, a major limitation of these experiments is the difficulty in visualizing the process in reservoir rock samples. Experimental observations using transparent glass models have been useful in this context and provide a sound physical basis for modelling gravitational gas migration in gas-oil systems. This paper presented a new pore network simulator that was capable of modelling the time-dependent migration of growing gas structures. Multiple pore filling events were dynamically modelled with interface tracking allowing the full range of migratory behaviours to be reproduced, including braided migration and discontinuous dispersed flow. Simulation results were compared with experiments and were found to be in excellent agreement. The paper presented the model and discussed the implication of evolution regime on recovery from heavy oil systems undergoing depressurization. The simulation results demonstrated the complex interaction of a number of network and fluid parameters. It was concluded that the concomitant effect on the competition between capillarity and buoyancy produced different gas evolution patterns during pressure depletion. 28 refs., 2 tabs., 19 figs.

  4. Thermal effects of condensing water have remained local

    International Nuclear Information System (INIS)

    Ilus, E.

    1997-01-01

    General eutrophication of the Gulf of Finland has played a major role in the biological changes that have taken place in the sea area off Loviisa nuclear power plant. The quantities of plant nutrients in the water are now 1.5 to 2 times greater than 20 years ago. Changes attributable to the thermal effects of the power plant's cooling waters have been relatively small, and they have been restricted to the immediate surroundings of the discharge area. The most distinct environmental effects have been discovered in the temperatures of sea water, in ice conditions and in water currents within the discharge area of cooling water. The most visible biological change that has a direct link to the thermal load resulting from the power plant is the more abundant aquatic flora near the discharge point of cooling water on the southwestern shores of the Haestholmsfjaerden. Similar growth of aquatic flora has also been discovered near the discharge outlet of Olkiluoto plant, although the nutrient contents of water there are only half of the values measured in the Loviisa area. Regular radiation monitoring of the areas surrounding the nuclear power plants began before the start up of the plants. The contents of radioactive substances discovered have been small and in agreement with the release data given by the power companies. (orig.)

  5. Metamorphism and Shear Localization in the Oceanic and Continental Lithosphere: A Local or Lithospheric-Scale Effect?

    Science.gov (United States)

    Montesi, L.

    2017-12-01

    Ductile rheologies are characterized by strain rate hardening, which favors deformation zones that are as wide as possible, thus minimizing strain rate and stress. By contrast, plate tectonics and the observation of ductile shear zones in the exposed middle to lower crust show that deformation is often localized, that is, strain (and likely strain rate) is locally very high. This behavior is most easily explained if the material in the shear zone is intrinsically weaker than the reference material forming the wall rocks. Many origins for that weakness have been proposed. They include higher temperature (shear heating), reduced grain size, and fabric. The latter two were shown to be the most effective in the middle crust and upper mantle (given observational limits restricting heating to 50K or less) but they were not very important in the lower crust. They are not sufficient to explain the generation of narrow plate boundaries in the oceans. We evaluate here the importance of metamorphism, especially related to hydration, in weakening the lithosphere. Serpentine is a major player in the dynamics of the oceanic lithosphere. Although its ductile behavior is poorly constrained, serpentine is likely to behave in a brittle or quasi-plastic manner with a reduced coefficient of friction, replacing stronger peridotite. Serpentinization sufficiently weakens the oceanic lithosphere to explain the generation of diffuse plate boundaries and, combined with grain size reduction, the development of narrow plate boundaries. Lower crust outcrops, especially in the Bergen Arc (Norway), display eclogite shear zones hosted in metastable granulites. The introduction of water triggered locally a metamorphic reaction that reduces rock strength and resulted in a ductile shear zone. The presence of these shear zones has been used to explain the weakness of the lower crust perceived from geodesy and seismic activity. We evaluate here how much strain rate may increase as a result of

  6. Rating the effectiveness of local tobacco policies for reducing youth smoking.

    Science.gov (United States)

    Lipperman-Kreda, Sharon; Friend, Karen B; Grube, Joel W

    2014-04-01

    Important questions remain regarding the effectiveness of local tobacco policies for preventing and reducing youth tobacco use and the relative importance of these policies. The aims of this paper are to: (1) compare policy effectiveness ratings provided by researchers and tobacco prevention specialists for individual local tobacco policies, and (2) develop and describe a systematic approach to score communities for locally-implemented tobacco policies. We reviewed municipal codes of 50 California communities to identify local tobacco regulations in five sub-domains. We then developed an instrument to rate the effectiveness of these policies and administered it to an expert panel of 40 tobacco researchers and specialists. We compared mean policy effectiveness ratings obtained from researchers and prevention specialists and used it to score the 50 communities. High inter-rater reliabilities obtained for each sub-domain indicated substantial agreement among the raters about relative policy effectiveness. Results showed that, although researchers and prevention specialists differed on the mean levels of policy ratings, their relative rank ordering of the effectiveness of policy sub-domains were very similar. While both researchers and prevention specialists viewed local outdoor clean air policies as least effective in preventing and reducing youth cigarette smoking, they rated tobacco sales policies and advertising and promotion as more effective than the other policies. Moreover, we found high correlations between community scores generated from researchers' and prevention specialists' ratings. This approach can be used to inform research on local policies and prevention efforts and help bridge the gap between research and practice.

  7. Local Transfer Coefficient, Smooth Channel

    Directory of Open Access Journals (Sweden)

    R. T. Kukreja

    1998-01-01

    Full Text Available Naphthalene sublimation technique and the heat/mass transfer analogy are used to determine the detailed local heat/mass transfer distributions on the leading and trailing walls of a twopass square channel with smooth walls that rotates about a perpendicular axis. Since the variation of density is small in the flow through the channel, buoyancy effect is negligible. Results show that, in both the stationary and rotating channel cases, very large spanwise variations of the mass transfer exist in he turn and in the region immediately downstream of the turn in the second straight pass. In the first straight pass, the rotation-induced Coriolis forces reduce the mass transfer on the leading wall and increase the mass transfer on the trailing wall. In the turn, rotation significantly increases the mass transfer on the leading wall, especially in the upstream half of the turn. Rotation also increases the mass transfer on the trailing wall, more in the downstream half of the turn than in the upstream half of the turn. Immediately downstream of the turn, rotation causes the mass transfer to be much higher on the trailing wall near the downstream corner of the tip of the inner wall than on the opposite leading wall. The mass transfer in the second pass is higher on the leading wall than on the trailing wall. A slower flow causes higher mass transfer enhancement in the turn on both the leading and trailing walls.

  8. An Effective Cuckoo Search Algorithm for Node Localization in Wireless Sensor Network.

    Science.gov (United States)

    Cheng, Jing; Xia, Linyuan

    2016-08-31

    Localization is an essential requirement in the increasing prevalence of wireless sensor network (WSN) applications. Reducing the computational complexity, communication overhead in WSN localization is of paramount importance in order to prolong the lifetime of the energy-limited sensor nodes and improve localization performance. This paper proposes an effective Cuckoo Search (CS) algorithm for node localization. Based on the modification of step size, this approach enables the population to approach global optimal solution rapidly, and the fitness of each solution is employed to build mutation probability for avoiding local convergence. Further, the approach restricts the population in the certain range so that it can prevent the energy consumption caused by insignificant search. Extensive experiments were conducted to study the effects of parameters like anchor density, node density and communication range on the proposed algorithm with respect to average localization error and localization success ratio. In addition, a comparative study was conducted to realize the same localization task using the same network deployment. Experimental results prove that the proposed CS algorithm can not only increase convergence rate but also reduce average localization error compared with standard CS algorithm and Particle Swarm Optimization (PSO) algorithm.

  9. The effects of local government investment on economic growth and employment: evidence from transitional China

    Institute of Scientific and Technical Information of China (English)

    Zhang Weiguo; Hou Yongjian

    2009-01-01

    Based on the panel data of 28 provinces in the year of 1987-2001,this paper examines the effects of the local government investment on economic growth and employment.The empirical result shows that the local government investment plays a significant positive role in economic growth and emplovment.However,while the proportion of local government investment to GDP had a remarkable rise after 1998.the elasticity of local government investment on economic growth declined,which shows that there is a hig room for raising the efficiency of local government mvestment.Moreover,the empirical examination shows that although local government investment had positive effect on employment,the elasticity had a decrease after 1994 when the tax-sharing system reform was put into practice.This shows that the positive role of local government investment on emplovment is also limited.This paper argues that the role of local governments as investors must be weakened,and local governments of different levels should lessen direct economic intervention and concentrate on public regulation.

  10. The 1448 earthquake in Catalonia. Some effects and local reactions

    Directory of Open Access Journals (Sweden)

    R. Salicrù i Lluch

    1995-06-01

    Full Text Available The May 1448 earthquake. the last destructive one that took place in Catalonia in the Middle Ages, was known chiefly from several chronistic and narrative medieval sources. To these sources I add new previously unknown data proceeding Eroin documentary archival sources in Barcelona, and other data that up to now have been wrongly considered as a consequence of the weak quake recorded in September 1450. They allow us to locate the epicentre in the Vall&s Oriental, around Llinars, to deny the existence of two almost simultaneous earthquakes, and to extend the range of the earthquake damage. to pinpoint them better and to suppose that the effects of the 1448 earthquake were more important than we had previously thought. All this information leads to several reflections on compulsory critical analysis of historical seismic documentary sources in order for them to be useful to historical seismicity. Finally. by the opposition of the three lands of documentary sources that refer to the damage caused by the earthquake in the township of Mataro. I show how natural catastrophes could be manipulated, and the skill of a society in exploiting them to deal with an adverse situation.

  11. Prediction of local effects of proposed cooling ponds

    International Nuclear Information System (INIS)

    Hicks, B.B.

    1978-01-01

    A Fog Excess Water (FEW) Index has been shown to provide a good measure of the likelihood for steam fog to occur at specific cooling pond installations. The FEW Index is derived from the assumption that the surface boundary layer over a cooling pond will be strongly convective, and that highly efficient vertical transport mechanisms will result in a thorough mixing of air saturated at surface temperature with ambient air aloft. Available data support this assumption. An extension of this approach can be used to derive a simple indicator for use in predicting the formation of rime ice in the immediate downwind environs of a cooling pond. In this case, it is supposed that rime ice will be deposited whenever steam fog and sub-freezing surface temperatures are predicted. This provides a convenient method for interpreting pre-existing meteorological information in order to assess possible icing effects while in the early design stages of the planning process. However, it remains necessary to derive accurate predictions of the cooling pond water surface temperature. Once a suitable and proven procedure for this purpose has been demonstrated, it is then a simple matter to employ the FEW Index in evaluations of the relative merits of alternative cooling pond designs, with the purpose of minimizing overall environmental impact

  12. The effect of urban design parameters on the local microclimate

    Energy Technology Data Exchange (ETDEWEB)

    Kakoniti, Androula; Georgiou, Gregoria; Neophytou, Marina [Department of Civil and Environmental Engineering, University of Cyprus, 1678 Nicosia (Cyprus); Marakkos, Konstantinos [Department of Aerospace Engineering, University of Manchester, M60 1QD, Manchester (United Kingdom)

    2015-01-22

    Two-dimensional steady-state simulations have been performed using the standard k-e turbulence model coupled with the heat transfer models available in the CFD software FLUENT 6.1, in order to examine the impact of radiation on the Urban Heat Island phenomenon. Specifically, the impact of radiation in three typical urban areas of Cyprus during the summer period is examined. The first geometry considered represents a typical suburban area and is termed as the reference geometry. The second geometry represents an area at the centre of a town with higher buildings and relatively narrower roads. The third geometry, on the other hand, describes a suburban area with wider roads and larger houses than the reference model. Computed values for air temperature in the urban street canyon have indicated that the increase in temperature associated with radiative heat transfer can be reduced by optimising the canyon geometry and, ultimately, help to mitigate the human thermal discomfort. The present study has also revealed that the selection of construction materials can be optimised to offer further reductions in the air temperature of the urban environment. It can be concluded that the combined effect of these remedies can lead to reductions in the energy consumption for building air-conditioning over the summer period.

  13. Irrigation enhances local warming with greater nocturnal warming effects than daytime cooling effects

    Science.gov (United States)

    Chen, Xing; Jeong, Su-Jong

    2018-02-01

    To meet the growing demand for food, land is being managed to be more productive using agricultural intensification practices, such as the use of irrigation. Understanding the specific environmental impacts of irrigation is a critical part of using it as a sustainable way to provide food security. However, our knowledge of irrigation effects on climate is still limited to daytime effects. This is a critical issue to define the effects of irrigation on warming related to greenhouse gases (GHGs). This study shows that irrigation led to an increasing temperature (0.002 °C year-1) by enhancing nighttime warming (0.009 °C year-1) more than daytime cooling (-0.007 °C year-1) during the dry season from 1961-2004 over the North China Plain (NCP), which is one of largest irrigated areas in the world. By implementing irrigation processes in regional climate model simulations, the consistent warming effect of irrigation on nighttime temperatures over the NCP was shown to match observations. The intensive nocturnal warming is attributed to energy storage in the wetter soil during the daytime, which contributed to the nighttime surface warming. Our results suggest that irrigation could locally amplify the warming related to GHGs, and this effect should be taken into account in future climate change projections.

  14. Effect of segmental, localized lower limb cooling on dynamic balance.

    Science.gov (United States)

    Montgomery, Roger E; Hartley, Geoffrey L; Tyler, Christopher J; Cheung, Stephen S

    2015-01-01

    This study aimed to determine the effect of cooling progressively greater portions of the lower extremities on dynamic balance and neuromuscular activation. Ten healthy males (22.8 ± 3.4 yr, 76.5 ± 9.1 kg) performed one room air temperature control (22.4°C ± 0.8°C) and three trials of cold water immersion at 12°C (lateral malleolus, ankle; lateral femoral epicondyle, knee; anterior superior iliac spine, hip) for 10 min before performing a unipedal balance test (Star Excursion Balance Test (SEBT)) with their dominant limb. Muscle activation of the vastus lateralis, biceps femoris, tibialis anterior, and lateral gastrocnemius was measured with surface EMG during the SEBT. Core temperature remained euthermic throughout all trials. Gastrocnemius temperature decreased from control (30.4°C ± 0.5°C) with knee (23.7°C ± 1.7°C) and hip immersion (22.4°C ± 1.0°C), whereas vastus lateralis temperature decreased from control (33.7°C ± 1.7°C) with hip immersion (27.3°C ± 2.0°C) (P water immersion influenced mean anterior and posterior reach distance on the SEBT in a dose-dependent fashion. Compared with those in control, mean anterior and posterior SEBT reach distances were not decreased with ankle (-1.38% and -0.74%, respectively) and knee immersion (-2.48% and -2.74%), whereas hip immersion significantly reduced SEBT by 4.73% and 4.05% (P lower extremities were cooled, with only the lateral gastrocnemius during the anterior SEBT approaching a decrease (P = 0.059). Cooling larger portions of the lower extremities progressively affect dynamic balance, and thermal protection strategies should focus on maintaining temperature in the large muscle mass of the thigh.

  15. Effects on functional outcome after IORT-containing multimodality treatment for locally advanced primary and locally recurrent rectal cancer

    NARCIS (Netherlands)

    Mannaerts, GHH; Rutten, HJT; Martijn, H; Hanssens, PEJ; Wiggers, T

    2002-01-01

    Purpose: In the treatment of patients with locally advanced primary or locally recurrent rectal cancer, much attention is focused on. the oncologic outcome. Little is known about the functional outcome. In this study, the functional outcome after a multimodality treatment for locally advanced

  16. Antiferromagnetic Ising model decorated with D-vector spins: Transversal and longitudinal local fields effects

    International Nuclear Information System (INIS)

    Vasconcelos Dos Santos, R.J.; Coutinho, S.

    1995-01-01

    The effect of a local field acting on decorating classical D-vector bond spins of an antiferromagnetic Ising model on the square lattice is studied for both the annealed isotropic and the axial decorated cases. In both models the effect on the phase diagrams of the transversal and the longitudinal components of the local field acting on the decorating spins are fully analyzed and discussed

  17. Spectroscopic study of local thermal effect in transparent glass ceramics containing nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Local thermal effect influencing the fluorescence of triply ionized rare earth ions doped in nanocrystals is studied with laser spectroscopy and theory of thermal transportation for transparent oxyfluoride glass ceramics containing nanocrystals. The result shows that the local temperature of the nanocrystals embedded in glass matrices is much higher than the environmental temperature of the sample. It is suggested that the temperature-dependent thermal energy induced by the light absorption must be considered when the theory of thermal transportation is applied to the study of local thermal effect.

  18. Spatial localization of the first and last enzymes effectively connects active metabolic pathways in bacteria.

    Science.gov (United States)

    Meyer, Pablo; Cecchi, Guillermo; Stolovitzky, Gustavo

    2014-12-14

    Although much is understood about the enzymatic cascades that underlie cellular biosynthesis, comparatively little is known about the rules that determine their cellular organization. We performed a detailed analysis of the localization of E.coli GFP-tagged enzymes for cells growing exponentially. We found that out of 857 globular enzymes, at least 219 have a discrete punctuate localization in the cytoplasm and catalyze the first or the last reaction in 60% of biosynthetic pathways. A graph-theoretic analysis of E.coli's metabolic network shows that localized enzymes, in contrast to non-localized ones, form a tree-like hierarchical structure, have a higher within-group connectivity, and are traversed by a higher number of feed-forward and feedback loops than their non-localized counterparts. A Gene Ontology analysis of these enzymes reveals an enrichment of terms related to essential metabolic functions in growing cells. Given that these findings suggest a distinct metabolic role for localization, we studied the dynamics of cellular localization of the cell wall synthesizing enzymes in B. subtilis and found that enzymes localize during exponential growth but not during stationary growth. We conclude that active biochemical pathways inside the cytoplasm are organized spatially following a rule where their first or their last enzymes localize to effectively connect the different active pathways and thus could reflect the activity state of the cell's metabolic network.

  19. Characterizing Time Irreversibility in Disordered Fermionic Systems by the Effect of Local Perturbations

    Science.gov (United States)

    Vardhan, Shreya; De Tomasi, Giuseppe; Heyl, Markus; Heller, Eric J.; Pollmann, Frank

    2017-07-01

    We study the effects of local perturbations on the dynamics of disordered fermionic systems in order to characterize time irreversibility. We focus on three different systems: the noninteracting Anderson and Aubry-André-Harper (AAH) models and the interacting spinless disordered t -V chain. First, we consider the effect on the full many-body wave functions by measuring the Loschmidt echo (LE). We show that in the extended or ergodic phase the LE decays exponentially fast with time, while in the localized phase the decay is algebraic. We demonstrate that the exponent of the decay of the LE in the localized phase diverges proportionally to the single-particle localization length as we approach the metal-insulator transition in the AAH model. Second, we probe different phases of disordered systems by studying the time expectation value of local observables evolved with two Hamiltonians that differ by a spatially local perturbation. Remarkably, we find that many-body localized systems could lose memory of the initial state in the long-time limit, in contrast to the noninteracting localized phase where some memory is always preserved.

  20. Effects of global and local contexts on chord processing: An ERP study.

    Science.gov (United States)

    Zhang, Jingjing; Zhou, Xuefeng; Chang, Ruohan; Yang, Yufang

    2018-01-31

    In real life, the processing of an incoming event is continuously influenced by prior information at multiple timescales. The present study investigated how harmonic contexts at both local and global levels influence the processing of an incoming chord in an event-related potentials experiment. Chord sequences containing two phrases were presented to musically trained listeners, with the last critical chord either harmonically related or less related to its preceding context at local and/or global levels. ERPs data showed an ERAN-like effect for local context in early time window and a N5-like component for later interaction between the local context and global context. These results suggest that both the local and global contexts influence the processing of an incoming music event, and the local effect happens earlier than the global. Moreover, the interaction between the local context and global context in N5 may suggest that music syntactic integration at local level takes place prior to the integration at global level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Numerical investigation on thermal performance and correlations of double skin facade with buoyancy-driven airflow

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, Alexandra; Zhai, Zhiqiang [Department of Civil, Environmental and Architectural Engineering, University of Colorado, UCB 428, ECOT 441, Boulder, CO 80309-0428 (United States)

    2008-07-01

    This paper briefly reviews the primary parameters for a double skin facade (DSF) design. The research presents an integrated and iterative modeling process for analyzing the thermal performance of DSF cavities with buoyancy-driven airflow by using a building energy simulation program (BESP) along with a computational fluid dynamics (CFD) package. A typical DSF cavity model has been established and simulated. The model and the modeling process have been calibrated and validated against the experimental data. The validated model was used to develop correlations that can be implemented in a BESP, allowing users to take advantage of the accuracy gained from CFD simulations without the required computation time. Correlations were developed for airflow rate through cavity, average and peak cavity air temperature, cavity air pressure, and interior convection coefficient. The correlations are valuable for 'back of the envelope' calculation and for examining accuracy of zonal-model-based energy and airflow simulation programs. (author)

  2. Kinetic energy and scalar spectra in high Rayleigh number axially homogeneous buoyancy driven turbulence

    Science.gov (United States)

    Pawar, Shashikant S.; Arakeri, Jaywant H.

    2016-06-01

    Kinetic energy and scalar spectra from the measurements in high Rayleigh number axially homogeneous buoyancy driven turbulent flow are presented. Kinetic energy and concentration (scalar) spectra are obtained from the experiments wherein density difference is created using brine and fresh water and temperature spectra are obtained from the experiments in which heat is used. Scaling of the frequency spectra of lateral and longitudinal velocity near the tube axis is closer to the Kolmogorov-Obukhov scaling, while the scalar spectra show some evidence of dual scaling, Bolgiano-Obukhov scaling followed by Obukhov-Corrsin scaling. These scalings are also observed in the corresponding second order spatial structure functions of velocity and concentration fluctuations.

  3. Education of Gifted Students with Virtual Physics Laboratory: Buoyancy Force Topic

    Directory of Open Access Journals (Sweden)

    Necati HIRCA

    2013-06-01

    Full Text Available Project-based learning approach is recommended for science education of gifted students for their independent learning will and they can intensify their attention on any issue for along time. In this study, the steps of the experiment buoyancy of liquids has been explained with the help of Algodoo Programme a learning environment in which gifted students test their hypotheses and can learn the concepts of physics with their own experiences. This study is tought to be used as a guidance material in the education of gifted students in Science and Art Centers in Turkey. Teachers in Science and Art Center (or who educate gifted students are generally inexperienced in the education of gifted students. Another problem of these teachers is the lack of adequate materials that the teachers use in the education of gifted students.

  4. Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane

    Energy Technology Data Exchange (ETDEWEB)

    Mashimo, T.; Abe, K.; Yoshiya, I.

    1986-04-01

    The effects of local anesthetics and a divalent cation, Ca2+, on the function of rhodopsin were estimated from the measurements of light-induced proton uptake. The light-induced proton uptake by rhodopsin in the rod outer segment disk membrane was enhanced at lower pH (4) but depressed at higher pHs (6 to 8) by the tertiary amine local anesthetics lidocaine, bupivacaine, tetracaine, and dibucaine. The order of local anesthetic-induced depression of the proton uptake followed that of their clinical anesthetic potencies. The depression of the proton uptake versus the concentration of the uncharged form of local anesthetic nearly describes the same curve for small and large dose of added anesthetic. Furthermore, a neutral local anesthetic, benzocaine, depressed the proton uptake at all pHs between 4 and 7. These results indicate that the depression of the proton uptake is due to the effect of only the uncharged form. It is hypothesized that the uncharged form of local anesthetics interacts hydrophobically with the rhodopsin in the disk membrane. The dual effect of local anesthetics on the proton uptake, on the other hand, suggests that the activation of the function of rhodopsin may be caused by the charged form. There was no significant change in the light-induced proton uptake by rhodopsin when 1 mM of Ca2+ was introduced into the disk membrane at varying pHs in the absence or presence of local anesthetics. This fact indicates that Ca2+ ion does not influence the diprotonating process of metarhodopsin; neither does it interfere with the local anesthetic-induced changes in the rhodopsin molecule.

  5. How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers’ Hydrostatic and Hydrodynamic Profiles?

    Science.gov (United States)

    Barbosa, Tiago M.; Costa, Mário J.; Morais, Jorge E; Moreira, Marc; Silva, António J.; Marinho, Daniel A.

    2012-01-01

    The aim of this research was to develop a path-flow analysis model to highlight the relationships between buoyancy and prone gliding tests and some selected anthropometrical and biomechanical variables. Thirty-eight young male swimmers (12.97 ± 1.05 years old) with several competitive levels were evaluated. It were assessed the body mass, height, fat mass, body surface area, vertical buoyancy, prone gliding after wall push-off, stroke length, stroke frequency and velocity after a maximal 25 [m] swim. The confirmatory model included the body mass, height, fat mass, prone gliding test, stroke length, stroke frequency and velocity. All theoretical paths were verified except for the vertical buoyancy test that did not present any relationship with anthropometrical and biomechanical variables nor with the prone gliding test. The good-of-fit from the confirmatory path-flow model, assessed with the standardized root mean square residuals (SRMR), is considered as being close to the cut-off value, but even so not suitable of the theory (SRMR = 0.11). As a conclusion, vertical buoyancy and prone gliding tests are not the best techniques to assess the swimmer’s hydrostatic and hydrodynamic profile, respectively. PMID:23486528

  6. Evaluation of local site effect from microtremor measurements in Babol City, Iran

    Science.gov (United States)

    Rezaei, Sadegh; Choobbasti, Asskar Janalizadeh

    2018-03-01

    Every year, numerous casualties and a large deal of financial losses are incurred due to earthquake events. The losses incurred by an earthquake vary depending on local site effect. Therefore, in order to conquer drastic effects of an earthquake, one should evaluate urban districts in terms of the local site effect. One of the methods for evaluating the local site effect is microtremor measurement and analysis. Aiming at evaluation of local site effect across the city of Babol, the study area was gridded and microtremor measurements were performed with an appropriate distribution. The acquired data was analyzed through the horizontal-to-vertical noise ratio (HVNR) method, and fundamental frequency and associated amplitude of the H/V peak were obtained. The results indicate that fundamental frequency of the study area is generally lower than 1.25 Hz, which is acceptably in agreement with the findings of previous studies. Also, in order to constrain and validate the seismostratigraphic model obtained with this method, the results were compared with geotechnical, geological, and seismic data. Comparing the results of different methods, it was observed that the presented geophysical method can successfully determine the values of fundamental frequency across the study area as well as local site effect. Using the data obtained from the analysis of microtremor, a microzonation map of fundamental frequency across the city of Babol was prepared. This map has numerous applications in designing high-rise building and urban development plans.

  7. Effects of surface roughness on plastic strain localization in polycrystalline aggregates

    Directory of Open Access Journals (Sweden)

    Guilhem Yoann

    2014-06-01

    Full Text Available The surface state of mechanical components differs according to applied loadings. Industrial processes may produce specific features at the surface, such as roughness, local hardening, residual stresses or recrystallization. Under fatigue loading, all these parameters will affect the component lifetime, but in different manner. A better understanding of each surface state parameter, separately first and then all combined, will provide a better prediction of fatigue life. The study focuses on the effect of surface roughness. Crystal plasticity finite element computations have been carried out on three-dimensional polycrystalline aggregates with different roughness levels. Local mechanical fields have been analyzed both at the surface and inside the bulk to highlight the competition between crystallography and roughness to impose localization patterns. As soon as surface roughness is strong enough, classical localization bands driven by grains orientation are replaced by localizations patterns driven by the local roughness topology. Nevertheless, this effect tends to decrease gradually under the surface, and it becomes usually negligible after the first layer of grains. The discussion allows us to characterize the influence of the surface state on the local mechanical fields.

  8. Forced and free convection flow with viscous dissipation effects: The method of parametric differentiation

    International Nuclear Information System (INIS)

    Hossain, M.A.; Arbad, O.

    1988-07-01

    Effect of buoyancy force in a laminar uniform forced convection flow past a semi-infinite vertical plate has been analyzed near the leading edge, taking into account the viscous dissipation. The coupled non-linear locally similar equations, which govern the flow, are solved by the method of parametric differentiation. Effects of the buoyancy force and the heat due to viscous dissipation on the flow and the temperature fields as well as on the wall shear-stress and the heat transfer at the surface of the plate are shown graphically for the values of the Prandtl number σ ranging from 10 -1 to 1.0. (author). 20 refs, 3 figs, 2 tabs

  9. Exploring the effect of diffuse reflection on indoor localization systems based on RSSI-VLC.

    Science.gov (United States)

    Mohammed, Nazmi A; Elkarim, Mohammed Abd

    2015-08-10

    This work explores and evaluates the effect of diffuse light reflection on the accuracy of indoor localization systems based on visible light communication (VLC) in a high reflectivity environment using a received signal strength indication (RSSI) technique. The effect of the essential receiver (Rx) and transmitter (Tx) parameters on the localization error with different transmitted LED power and wall reflectivity factors is investigated at the worst Rx coordinates for a directed/overall link. Since this work assumes harsh operating conditions (i.e., a multipath model, high reflectivity surfaces, worst Rx position), an error of ≥ 1.46 m is found. To achieve a localization error in the range of 30 cm under these conditions with moderate LED power (i.e., P = 0.45 W), low reflectivity walls (i.e., ρ = 0.1) should be used, which would enable a localization error of approximately 7 mm at the room's center.

  10. The analgesic effect of wound infiltration with local anaesthetics after breast surgery

    DEFF Research Database (Denmark)

    Byager, N; Hansen, Mads; Mathiesen, Ole

    2014-01-01

    significant reduction in post-operative, supplemental opioid consumption that was, however, of limited clinical relevance. CONCLUSION: Wound infiltration with local anaesthetics may have a modest analgesic effect in the first few hours after surgery. Pain after breast surgery is, however, generally mild......BACKGROUND: Wound infiltration with local anaesthetics is commonly used during breast surgery in an attempt to reduce post-operative pain and opioid consumption. The aim of this review was to evaluate the effect of wound infiltration with local anaesthetics compared with a control group on post......-operative pain after breast surgery. METHODS: A systematic review was performed by searching PubMed, Google Scholar, the Cochrane database and Embase for randomised, blinded, controlled trials of wound infiltration with local anaesthetics for post-operative pain relief in female adults undergoing breast surgery...

  11. Local spin valve effect in lateral (Ga,MnAs/GaAs spin Esaki diode devices

    Directory of Open Access Journals (Sweden)

    M. Ciorga

    2011-06-01

    Full Text Available We report here on a local spin valve effect observed unambiguously in lateral all-semiconductor all-electrical spin injection devices, employing p+ −(Ga,MnAs/n+ −GaAs Esaki diode structures as spin aligning contacts. We discuss the observed local spin-valve signal as a result of the interplay between spin-transport-related contribution and the tunneling anisotropic magnetoresistance of the magnetic contacts. The magnitude of the spin-related magnetoresistance change is equal to 30 Ω which is twice the magnitude of the measured non-local signal.

  12. Low-Income Demand for Local Telephone Service: Effects of Lifeline and Linkup

    OpenAIRE

    Daniel Ackerberg; Michael Riordan; Gregory Rosston; Bradley Wimmer

    2008-01-01

    A comprehensive data set on local telephone service prices is used to evaluate the effect of Lifeline and Linkup programs on the telephone penetration rates of low-income households in the United States. Lifeline and Linkup programs respectively subsidize the monthly subscription and initial installation charges of eligible low-income households. Telephone penetration rates are explained by an estimated nonlinear function of local service characteristics (including subsidized prices) and the ...

  13. Local effects in thin elastic shell due to thermal and mechanical loadings

    International Nuclear Information System (INIS)

    Taheri, S.

    1987-01-01

    For a thick cylinder (1/15)<(h/rm)<(1/3) the local effect is represented by the same field. When the local effect is negligible the Love-Kirchhoff solution is valid for a thick cylinder. A shear effect shell theory may give for a thin cylinder a large error compared to the exact 3D solution on a thermal shock. The Love-Kirchhoff solution is generally not valid in the vicinity of a clamped or simply supported edge. A finite element program of thin shell with shear effect or thick shell ist not really reliable. A combination of 3D local solution and Love-Kirchhoff global solution through a transition zone may replace a complete 3D solution for not very thick structures. (orig./GL)

  14. When local anesthesia becomes universal: Pronounced systemic effects of subcutaneous lidocaine in bullfrogs (Lithobates catesbeianus)

    DEFF Research Database (Denmark)

    Williams, Catherine; Alstrup, Aage Kristian Olsen; Bertelsen, Mads Frost

    2017-01-01

    Sodium channel blockers are commonly injected local anesthetics but are also routinely used for general immersion anesthesia in fish and amphibians. Here we report the effects of subcutaneous injection of lidocaine (5 or 50mgkg-1) in the hind limb of bullfrogs (Lithobates catesbeianus) on reflexes...... regained over 4h. Systemic sedative effects were not coupled to local anti-nociception, as a forceps pinch test at the site of injection provoked movement at the height of the systemic effect (tested at 81±4min). Amphibians are routinely subject to general anesthesia via exposure to sodium channel blockers...

  15. The Contradictory Effect of the "Global" on the "Local": Japanese Behaviour and Attitudes towards English Use in Local Contexts

    Science.gov (United States)

    Terasawa, Takunori

    2018-01-01

    This paper aims to establish that globalised social and linguistic changes have a more complicated impact on local behaviours and attitudes than is believed. Based on statistical analysis of nationally representative surveys in Japan, the paper presents evidence against the following two propositions: (1) globalisation increases local demand for…

  16. Effect of local allergen priming on early, late, delayed-phase, and epicutaneous skin reactions

    NARCIS (Netherlands)

    Weller, F. R.; Weller, M. S.; Jansen, H. M.; de Monchy, J. G.

    1996-01-01

    Allergic disease is reflected in a chronic inflammatory response to an allergen. It is thought that local allergen priming underlies this chronicity. To assess the effect of allergen priming on the amplitude and histologic effect of the allergic reaction, four sequential, intracutaneous skin tests

  17. Effect of local allergen priming on early, late, delayed-phase, and epicutaneous skin reactions

    NARCIS (Netherlands)

    Weller, FR; Weller, MS; Jansen, HM; deMonchy, JGR

    1996-01-01

    Allergic disease is renected in a chronic inflammatory response to an allergen. It is thought that local allergen priming underlies this chronicity. To assess the effect of allergen priming on the amplitude and histologic effect of the allergic reaction, four sequential, intracutaneous skin tests

  18. Investigation of ELM [edge localized mode] Dynamics with the Resonant Magnetic Perturbation Effects

    Energy Technology Data Exchange (ETDEWEB)

    Pankin, Alexei Y.; Kritz, Arnold H.

    2011-07-19

    Topics covered are: anomalous transport and E x B flow shear effects in the H-mode pedestal; RMP (resonant magnetic perturbation) effects in NSTX discharges; development of a scaling of H-mode pedestal in tokamak plasmas with type I ELMs (edge localized modes); and divertor heat load studies.

  19. Effects of Oil Spillage on Soil Fertility in Udu Local Government Area ...

    African Journals Online (AJOL)

    The study examines the effects of oil spillage on soil fertility in Udu Local Government Area of Delta State, with the aim of determining the effects of oil spillage on physical and chemical properties of the soils. Soil samples were collected from two experimental sites namely: oil polluted and non oil polluted plots in the study ...

  20. 42 CFR 54.11 - Effects on State and local funds.

    Science.gov (United States)

    2010-10-01

    ... AND/OR PROJECTS FOR ASSISTANCE IN TRANSITION FROM HOMELESSNESS GRANTS § 54.11 Effects on State and... 42 Public Health 1 2010-10-01 2010-10-01 false Effects on State and local funds. 54.11 Section 54.11 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS CHARITABLE...

  1. Cultivating a Community of Effective Special Education Teachers: Local Special Education Administrators' Roles

    Science.gov (United States)

    Bettini, Elizabeth; Benedict, Amber; Thomas, Rachel; Kimerling, Jenna; Choi, Nari; McLeskey, James

    2017-01-01

    Evidence of the powerful impact teachers have on student achievement has led to an intensive focus on cultivating effective teachers, including special education teachers (SETs). Local special education administrators (LSEAs) share responsibility for cultivating effective SETs throughout their districts. However, the roles LSEAs play in this…

  2. Investigation of ELM [edge localized mode] Dynamics with the Resonant Magnetic Perturbation Effects

    International Nuclear Information System (INIS)

    Pankin, Alexei Y.; Kritz, Arnold H.

    2011-01-01

    Topics covered are: anomalous transport and E f- B flow shear effects in the H-mode pedestal; RMP (resonant magnetic perturbation) effects in NSTX discharges; development of a scaling of H-mode pedestal in tokamak plasmas with type I ELMs (edge localized modes); and divertor heat load studies

  3. Endoscopic Carpal Tunnel Release using a modified application technique of local anesthesia: safety and effectiveness

    Directory of Open Access Journals (Sweden)

    Al-Khayat Jehad

    2008-04-01

    Full Text Available Abstract Background Local anesthesia is widely used for open carpal tunnel release. However, injection of local anesthesia as described by Altissimi and Mancini (1988 can interfere with endoscopic carpal tunnel release, by increasing the bulk of synovial layers and consequently result in worsening of the view. Purpose The purpose of this study was to evaluate the safety, efficacy using modified technique for application of local anesthesia. Methods 33 patients suffering from gradual increasing symptoms of carpal tunnel syndrome. The patients were also asked to evaluate the pain associated with injection as well as tourniquet during surgery using Visual Analogue Scale (VAS (ranging from 0 = no pain to 10 = maximum pain. Results One patient required additionally local anesthesia because of mild pain in the hand. The tourniquet was inflated for 13.00 (2.8 min. The pain score related to injection was 2.5 (0.8 and to tourniquet was 3.6 (0.9. Inflation of the tourniquet was well tolerated by all patients. Postoperative neurological sensory and motor deficits related to surgery and local blocks were not occurred. Conclusion Endoscopic release of the carpal tunnel syndrome in local anesthesia is effective, well tolerated and safe. This kind of application of local anesthesia did not reduce visibility.

  4. Imprints of local lightcone \\ projection effects on the galaxy bispectrum. Part II

    Energy Technology Data Exchange (ETDEWEB)

    Jolicoeur, Sheean; Umeh, Obinna; Maartens, Roy; Clarkson, Chris, E-mail: beautifulheart369@gmail.com, E-mail: umeobinna@gmail.com, E-mail: roy.maartens@gmail.com, E-mail: chris.clarkson@qmul.ac.uk [Department of Physics and Astronomy, University of the Western Cape, Cape Town 7535 (South Africa)

    2017-09-01

    General relativistic imprints on the galaxy bispectrum arise from observational (or projection) effects. The lightcone projection effects include local contributions from Doppler and gravitational potential terms, as well as lensing and other integrated contributions. We recently presented for the first time, the correction to the galaxy bispectrum from all local lightcone projection effects up to second order in perturbations. Here we provide the details underlying this correction, together with further results and illustrations. For moderately squeezed shapes, the correction to the Newtonian prediction is ∼ 30% on equality scales at z ∼ 1. We generalise our recent results to include the contribution, up to second order, of magnification bias (which affects some of the local terms) and evolution bias.

  5. Dynamics of local isolated magnetic flux tubes in a fast-rotating stellar atmosphere

    International Nuclear Information System (INIS)

    Chou, W.; Tajima, C.T.; Shibata, K.

    1998-01-01

    Dynamics of magnetic flux tubes in the fast rotating stellar atmosphere is studied. We focus on the effects and signatures of the instability of the flux tube emergence influenced by the Coriolis force. We present the result from a linear stability analysis and discuss its possible signatures in the course of the evolution of G-type and M-type stars. We present a three dimensional magnetohydrodynamical simulation of local isolated magnetic flux tubes under a magnetic buoyancy instability in co-rotating Cartesian coordinates. We find that the combination of the buoyancy instability and the Coriolis effect gives rise to a mechanism, to twist the emerging magnetic flux tube into a helical structure. The tilt angle, east-west asymmetry and magnetic helicity of the Twisted flux tubes in the simulations are studied in detail. The linear and nonlinear analyses provide hints as to what kind of pattern of large spots in young M-type main-sequence stars might be observed. We find that young and old G-type stars may have different distributions of spots while M-type stars may always have low latitudes spots. The size of stellar spots may decrease when a star becomes older, due to the decreasing of magnetic field. A qualitative comparison with solar observations is also presented

  6. Effect of Localizer Radiography Projection on Organ Dose at Chest CT with Automatic Tube Current Modulation.

    Science.gov (United States)

    Saltybaeva, Natalia; Krauss, Andreas; Alkadhi, Hatem

    2017-03-01

    Purpose To calculate the effect of localizer radiography projections to the total radiation dose, including both the dose from localizer radiography and that from subsequent chest computed tomography (CT) with tube current modulation (TCM). Materials and Methods An anthropomorphic phantom was scanned with 192-section CT without and with differently sized breast attachments. Chest CT with TCM was performed after one localizer radiographic examination with anteroposterior (AP) or posteroanterior (PA) projections. Dose distributions were obtained by means of Monte Carlo simulations based on acquired CT data. For Monte Carlo simulations of localizer radiography, the tube position was fixed at 0° and 180°; for chest CT, a spiral trajectory with TCM was used. The effect of tube start angles on dose distribution was investigated with Monte Carlo simulations by using TCM curves with fixed start angles (0°, 90°, and 180°). Total doses for lungs, heart, and breast were calculated as the sum of the dose from localizer radiography and CT. Image noise was defined as the standard deviation of attenuation measured in 14 circular regions of interest. The Wilcoxon signed rank test, paired t test, and Friedman analysis of variance were conducted to evaluate differences in noise, TCM curves, and organ doses, respectively. Results Organ doses from localizer radiography were lower when using a PA instead of an AP projection (P = .005). The use of a PA projection resulted in higher TCM values for chest CT (P chest CT. © RSNA, 2016 Online supplemental material is available for this article.

  7. Effects of Educating Local Government Officers and Healthcare and Welfare Professionals in Suicide Prevention

    Directory of Open Access Journals (Sweden)

    Yoshio Hirayasu

    2012-02-01

    Full Text Available Suicide is a major public health issue. In Japan, local governments are responsible for suicide prevention, and local government officers are therefore expected to act as gatekeepers for suicide prevention. In this study, through a questionnaire survey, the authors examined the current knowledge and attitudes concerning suicide prevention among local government officers and healthcare and welfare professionals, and the effects of providing suicide prevention education on their knowledge of and attitudes toward suicide and its prevention. One hundred eighty-three local government officers and 432 healthcare/welfare professionals completed the survey before and after a single education session. Before the session, the local government officers and healthcare/welfare professionals showed mainly positive attitudes toward suicide prevention efforts, with little difference between the two groups. After the training, knowledge and attitudes were further improved for most questionnaire items. Respondents with one or more experiences of suicide prevention training showed significantly more knowledge and positive attitudes before the training than those with no such experience. Moreover, knowledge of depression and having a sympathetic attitude were found to be especially associated with the overall attitude that “suicide can be prevented”. Training in suicide prevention was shown to be effective in promoting appropriate knowledge and attitudes among local government officers and healthcare/welfare professionals who are gatekeepers for preventing suicide. Our findings confirm the importance of suicide prevention education, and will contribute to creating a standard educational program on suicide prevention in Japan.

  8. Reirradiation of nasopharyngeal carcinoma with intracavitary mold brachytherapy: an effective means of local salvage

    International Nuclear Information System (INIS)

    Law, Stephen C.K.; Lam, W.-K.; Ng, M.-F.; Au, S.-K.; Mak, W.-T.; Lau, W.-H.

    2002-01-01

    Purpose: To assess the role of intracavitary mold brachytherapy in salvaging local failure of nasopharyngeal carcinoma (NPC). Methods and Materials: The outcomes of 118 consecutive NPC patients with local failure treated with mold brachytherapy between 1989 and 1996 were retrospectively reviewed. Eleven patients received additional external radiotherapy. Results: All molds were tailor-made, and the whole procedure was performed under local anesthesia. Pharyngeal recess dissection was routinely performed to allow direct contact of the radioactive source with the pharyngeal recess, a common site of local failure. Initially, the molds were preloaded with 192 Ir wires, but since 1992, the sources have been manually afterloaded; the mold has also been redesigned for better conformity, ease of insertion, and radiation safety. Using brachytherapy alone, 50-55 Gy was given for recurrence in 4-7 days; for persistence, 40 Gy was administered. The overall complete remission rate was 97%. The rates of 5-year local control, relapse-free survival, disease-specific survival, overall survival, and major complication were 85%, 68.3%, 74.8%, 61.3%, and 46.9%, respectively. Major complications included nasopharyngeal necrosis with headache, necrosis of cervical vertebrae with atlantoaxial instability, temporal lobe necrosis, and palsy of the cranial nerves. The afterloaded mold was as effective as the preloaded version, but with fewer complications. Conclusions: Intracavitary mold brachytherapy was effective in salvaging NPC with early-stage local persistence or first recurrence

  9. Local-Scale Simulations of Nucleate Boiling on Micrometer Featured Surfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sitaraman, Hariswaran [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dede, Ercan M. [Toyota Research Institute of North America; Joshi, Shailesh N. [Toyota Research Institute of North America; Zhou, Feng [Toyota Research Institute of North America

    2017-08-03

    A high-fidelity computational fluid dynamics (CFD)-based model for bubble nucleation of the refrigerant HFE7100 on micrometer-featured surfaces is presented in this work. The single-fluid incompressible Navier-Stokes equations, along with energy transport and natural convection effects are solved on a featured surface resolved grid. An a priori cavity detection method is employed to convert raw profilometer data of a surface into well-defined cavities. The cavity information and surface morphology are represented in the CFD model by geometric mesh deformations. Surface morphology is observed to initiate buoyancy-driven convection in the liquid phase, which in turn results in faster nucleation of cavities. Simulations pertaining to a generic rough surface show a trend where smaller size cavities nucleate with higher wall superheat. This local-scale model will serve as a self-consistent connection to larger device scale continuum models where local feature representation is not possible.

  10. Local-Scale Simulations of Nucleate Boiling on Micrometer-Featured Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sitaraman, Hariswaran [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dede, Ercan M. [Toyota Research Institute of North America; Joshi, Shailesh N. [Toyota Research Institute of North America; Zhou, Feng [Toyota Research Institute of North America

    2017-07-12

    A high-fidelity computational fluid dynamics (CFD)-based model for bubble nucleation of the refrigerant HFE7100 on micrometer-featured surfaces is presented in this work. The single-fluid incompressible Navier-Stokes equations, along with energy transport and natural convection effects are solved on a featured surface resolved grid. An a priori cavity detection method is employed to convert raw profilometer data of a surface into well-defined cavities. The cavity information and surface morphology are represented in the CFD model by geometric mesh deformations. Surface morphology is observed to initiate buoyancy-driven convection in the liquid phase, which in turn results in faster nucleation of cavities. Simulations pertaining to a generic rough surface show a trend where smaller size cavities nucleate with higher wall superheat. This local-scale model will serve as a self-consistent connection to larger device scale continuum models where local feature representation is not possible.

  11. Vapor-based interferometric measurement of local evaporation rate and interfacial temperature of evaporating droplets.

    Science.gov (United States)

    Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

    2014-03-04

    The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory.

  12. The Effect of IFRS Adoption on the Financial Reports of Local Government Entities

    Directory of Open Access Journals (Sweden)

    Kamran Ahmed

    2012-09-01

    Full Text Available This paper aims to analyse the changes in accounting surplus (loss, equity and assets, and liabilities as a result of accounting policy changes from the Australian Accounting Standards (AAS to the International Financial Reporting Standards (IFRS in Australian local government entities. Using the reconciliation notes disclosed by 117 local government entities, evidence is provided on the effects of IFRS adoption by identifying the key items that of difference between IFRS and AASB. The results show some differences between two sets of accounts prepared under these different accounting standards. While the average surplus (loss of local councils has decreased, their equities, assets and liabilities have increased, with no major significant changes in their overall financial position, except for liabilities. These results indicate the possible consequences of the adoption of IFRS by local government entities in other countries on performance indicators who have or are yet to implement these standards.

  13. The effect of walking speed on local dynamic stability is sensitive to calculation methods

    DEFF Research Database (Denmark)

    Stenum, Jan; Bruijn, Sjoerd M; Jensen, Bente Rona

    2014-01-01

    Local dynamic stability has been assessed by the short-term local divergence exponent (λS), which quantifies the average rate of logarithmic divergence of infinitesimally close trajectories in state space. Both increased and decreased local dynamic stability at faster walking speeds have been...... reported. This might pertain to methodological differences in calculating λS. Therefore, the aim was to test if different calculation methods would induce different effects of walking speed on local dynamic stability. Ten young healthy participants walked on a treadmill at five speeds (60%, 80%, 100%, 120......% and 140% of preferred walking speed) for 3min each, while upper body accelerations in three directions were sampled. From these time-series, λS was calculated by three different methods using: (a) a fixed time interval and expressed as logarithmic divergence per stride-time (λS-a), (b) a fixed number...

  14. Variational local moment approach: From Kondo effect to Mott transition in correlated electron systems

    International Nuclear Information System (INIS)

    Kauch, Anna; Byczuk, Krzysztof

    2012-01-01

    The variational local moment approach (VLMA) solution of the single impurity Anderson model is presented. It generalizes the local moment approach of Logan et al. by invoking the variational principle to determine the lengths of local moments and orbital occupancies. We show that VLMA is a comprehensive, conserving and thermodynamically consistent approximation and treats both Fermi and non-Fermi liquid regimes as well as local moment phases on equal footing. We tested VLMA on selected problems. We solved the single- and multi-orbital impurity Anderson model in various regions of parameters, where different types of Kondo effects occur. The application of VLMA as an impurity solver of the dynamical mean-field theory, used to solve the multi-orbital Hubbard model, is also addressed.

  15. Geometric effects of 90-degree vertical elbows on local two-phase flow parameters

    International Nuclear Information System (INIS)

    Yadav, M.; Worosz, T.; Kim, S.

    2011-01-01

    This study presents the geometric effects of 90-degree vertical elbows on the development of the local two-phase flow parameters. A multi-sensor conductivity probe is used to measure local two-phase flow parameters. It is found that immediately downstream of the vertical-upward elbow, the bubbles have a bimodal distribution along the horizontal radius of the pipe cross-section causing a dual-peak in the profiles of local void fraction and local interfacial area concentration. Immediately downstream of the vertical-downward elbow it is observed that the bubbles tend to migrate towards the inside of the elbow's curvature. The axial transport of void fraction and interfacial area concentration indicates that the elbows promote bubble disintegration. Preliminary predictions are obtained from group-one interfacial area transport equation (IATE) model for vertical-upward and vertical-downward two-phase flow. (author)

  16. IMPACT OF SOCIAL CAPITAL CHARACTERISTICS ON THE EFFECTIVENESS OF COMMUNITY-BASED APPROACH TO LOCAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    N. Grazhevska

    2013-10-01

    Full Text Available The article examines the impact of social capital characteristics of local communities on the effectiveness of the community-based approach to economic development. The conclusion that such social capital characteristics as (antipaternalism, solidarity and cooperation have the greatest importance for the economic development is made based on the analysis of UNDP and the European Union project “Community-based approach to local development”. It was hypothesized that the creation of community organizations could be an effective mechanism to actualize the existing social capital of rural communities in Ukraine.

  17. Reaching across the Mekong: Local Socioeconomic and Gender Effects of Lao-Thai Crossborder Linkages

    Directory of Open Access Journals (Sweden)

    José Edgardo Gomez, Jr.

    2011-01-01

    Full Text Available Following trade agreements between ASEAN states, the expansion of cross-border roads and bridges between Laos and Thailand has linked local communities and distant markets in increasingly diverse ways. Although the planned impacts of such integration are expected to be beneficial, effects on the ground vary, as witnessed at a sleepy outpost in Xayabury and a more vibrant crossing in Savannakhet. This paper discusses first the physical setting of such border facilities, and then explores their actual local effects on traders’ activities, highlighting changes in gender roles and perceptions of entrepreneurial competition participated in by women in the two research sites.

  18. Effect of local x-irradiation on mice reproduction in two successive generations

    International Nuclear Information System (INIS)

    Strel'nikova, N.K.; Lisenkova, L.N.

    1978-01-01

    For an experimental assessment of the biologic effectiveness of a single exposure to local irradiation exposure in simulating the conditions of exposure in X ray studies, an experiment was carried out on white mice. Mice of two successive generations were exposed to local X irradiation in the eye region. The radiation was found to bring about changes in the reproductive function (such as sterility, reduced litter size and fertility of females); these changes being dose-dependent in a nonlinear manner. The biologic effect of irradiation was greater in the second-generation mice

  19. The effect of hydrogen on the parameters of plastic deformation localization in low carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Lunev, Aleksey G., E-mail: agl@ispms.tsc.ru, E-mail: nadjozhkin@ispms.tsc.ru; Nadezhkin, Mikhail V., E-mail: agl@ispms.tsc.ru, E-mail: nadjozhkin@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Shlyakhova, Galina V., E-mail: shgv@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and Seversk State Technological Institute (National Research Nuclear University MEPhI), Seversk, 636036 (Russian Federation); Barannikova, Svetlana A., E-mail: bsa@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Tomsk State University of Architecture and Building, Tomsk, 634003 (Russian Federation); Zuev, Lev B., E-mail: lbz@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    In the present study, the effect of interstitial hydrogen atoms on the mechanical properties and plastic strain localization patterns in tensile tested polycrystals of low-carbon steel Fe-0.07%C has been studied using double exposure speckle photography technique. The main parameters of plastic flow localization at various stages of deformation hardening have been determined in polycrystals of steel electrolytically saturated with hydrogen in a three-electrode electrochemical cell at a controlled constant cathode potential. Also, the effect of hydrogen on changing of microstructure by using optical microscopy has been demonstrated.

  20. What Makes the Bangladesh Local Government Engineering Department (LGED) So Effective?

    OpenAIRE

    Fujita, Yasuo

    2011-01-01

    The Local Government Engineering Department (LGED) is renowned for its superior effectiveness compared with other public organizations in Bangladesh. Using the management and organizational theory framework, this paper attempts to answer the following two related questions: (i) why is LGED so effective, and (ii) has there been complementarity between LGED’s own strengths and the capacity development support of its donors. LGED’s business domain has been conducive to its effectiveness and to t...

  1. Development of consensus treatment plans for juvenile localized scleroderma: a roadmap toward comparative effectiveness studies in juvenile localized scleroderma.

    Science.gov (United States)

    Li, Suzanne C; Torok, Kathryn S; Pope, Elena; Dedeoglu, Fatma; Hong, Sandy; Jacobe, Heidi T; Rabinovich, C Egla; Laxer, Ronald M; Higgins, Gloria C; Ferguson, Polly J; Lasky, Andrew; Baszis, Kevin; Becker, Mara; Campillo, Sarah; Cartwright, Victoria; Cidon, Michael; Inman, Christi J; Jerath, Rita; O'Neil, Kathleen M; Vora, Sheetal; Zeft, Andrew; Wallace, Carol A; Ilowite, Norman T; Fuhlbrigge, Robert C

    2012-08-01

    Juvenile localized scleroderma (LS) is a chronic inflammatory skin disorder associated with substantial morbidity and disability. Although a wide range of therapeutic strategies has been reported in the literature, a lack of agreement on treatment specifics and accepted methods for clinical assessment has made it difficult to compare approaches and identify optimal therapy. Our objective was to develop standardized treatment plans, clinical assessments, and response criteria for active, moderate to high severity juvenile LS. A core group of pediatric rheumatologists, dermatologists, and a lay advisor was engaged by the Childhood Arthritis and Rheumatology Research Alliance (CARRA) to develop standardized treatment plans and assessment parameters for juvenile LS using consensus methods/nominal group techniques. Recommendations were validated in 2 face-to-face conferences with a larger group of practitioners with expertise in juvenile LS and with the full membership of CARRA, which encompasses the majority of pediatric rheumatologists in the US and Canada. Consensus was achieved on standardized treatment plans that reflect the prevailing treatment practices of CARRA members. Standardized clinical assessment methods and provisional treatment response criteria were also developed. Greater than 90% of pediatric rheumatologists responding to a survey (66% of CARRA membership) affirmed the final recommendations and agreed to utilize these consensus plans to treat patients with juvenile LS. Using consensus methodology, we have developed standardized treatment plans and assessment methods for juvenile LS. The high level of support among pediatric rheumatologists will support future comparative effectiveness studies and enable the development of evidence-based guidelines for the treatment of juvenile LS. Copyright © 2012 by the American College of Rheumatology.

  2. Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy.

    Science.gov (United States)

    Ponganis, P J; St Leger, J; Scadeng, M

    2015-03-01

    The anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body O2 store, buoyancy and hence the overall diving physiology of penguins. Therefore, three-dimensional reconstructions from computerized tomographic (CT) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [Adélie (Pygoscelis adeliae), king (Aptenodytes patagonicus) and emperor (A. forsteri) penguins]. Lung volumes scaled to body mass according to published avian allometrics. Air sac volumes at 30 cm H2O (2.94 kPa) inflation pressure, the assumed maximum volume possible prior to deep dives, were two to three times allometric air sac predictions and also two to three times previously determined end-of-dive total air volumes. Although it is unknown whether penguins inhale to such high volumes prior to dives, these values were supported by (a) body density/buoyancy calculations, (b) prior air volume measurements in free-diving ducks and (c) previous suggestions that penguins may exhale air prior to the final portions of deep dives. Based upon air capillary volumes, parabronchial volumes and tracheobronchial volumes estimated from the measured lung/airway volumes and the only available morphometry study of a penguin lung, the presumed maximum air sac volumes resulted in air sac volume to air capillary/parabronchial/tracheobronchial volume ratios that were not large enough to prevent barotrauma to the non-collapsing, rigid air capillaries during the deepest dives of all three species, and during many routine dives of king and emperor penguins. We conclude that volume reduction of airways and lung air spaces, via compression, constriction or blood engorgement, must occur to provide pulmonary baroprotection at depth. It is also possible that relative air capillary and parabronchial volumes are

  3. 2016 National Park visitor spending effects: Economic contributions to local communities, states, and the Nation

    Science.gov (United States)

    Cullinane Thomas, Catherine; Koontz, Lynne

    2017-01-01

    The National Park Service (NPS) manages the Nation’s most iconic destinations that attract millions of visitors from across the Nation and around the world. Trip-related spending by NPS visitors generates and supports a considerable amount of economic activity within park gateway communities. This economic effects analysis measures how NPS visitor spending cycles through local economies, generating business sales and supporting jobs and income. In 2016, the National Park System received an estimated 330,971,689 recreation visits. Visitors to National Parks spent an estimated $18.4 billion in local gateway regions (defined as communities within 60 miles of a park). The contribution of this spending to the national economy was 318 thousand jobs, $12.0 billion in labor income, $19.9 billion in value added, and $34.9 billion in economic output. The lodging sector saw the highest direct contributions with $5.7 billion in economic output directly contributed to local gateway economies nationally. The sector with the next greatest direct contributions was the restaurants and bars sector, with $3.7 billion in economic output directly contributed to local gateway economies nationally. Results from the Visitor Spending Effects report series are available online via an interactive tool. Users can view year-by-year trend data and explore current year visitor spending, jobs, labor income, value added, and economic output effects by sector for national, state, and local economies. This interactive tool is available at https://www.nps.gov/subjects/socialscience/vse.htm.

  4. 2015 National Park visitor spending effects: Economic contributions to local communities, states, and the nation

    Science.gov (United States)

    Cullinane Thomas, Catherine M.; Koontz, Lynne

    2016-01-01

    The National Park Service (NPS) manages the Nation’s most iconic destinations that attract millions of visitors from across the Nation and around the world. Trip-related spending by NPS visitors generates and supports a considerable amount of economic activity within park gateway communities. This economic effects analysis measures how NPS visitor spending cycles through local economies, generating business sales and supporting jobs and income.In 2015, the National Park System received over 307.2 million recreation visits. NPS visitors spent \\$16.9 billion in local gateway regions (defined as communities within 60 miles of a park). The contribution of this spending to the national economy was 295 thousand jobs, \\$11.1 billion in labor income, \\$18.4 billion in value added, and \\$32.0 billion in economic output. The lodging sector saw the highest direct contributions with \\$5.2 billion in economic output directly contributed to local gateway economies nationally. The sector with the next greatest direct contributions was the restaurants and bar sector, with \\$3.4 billion in economic output directly contributed to local gateway economies nationally.Results from the Visitor Spending Effects report series are available online via an interactive tool. Users can view year-by-year trend data and explore current year visitor spending, jobs, labor income, value added, and economic output effects by sector for national, state, and local economies. This interactive tool is available at http://go.nps.gov/vse.

  5. 2017 National Park visitor spending effects : Economic contributions to local communities, states, and the Nation

    Science.gov (United States)

    Cullinane Thomas, Catherine M.; Koontz, Lynne; Cornachione, Egan

    2018-01-01

    The National Park Service (NPS) manages the Nation’s most iconic destinations that attract millions of visitors from across the Nation and around the world. Trip-related spending by NPS visitors generates and supports a considerable amount of economic activity within park gateway communities. This economic effects analysis measures how NPS visitor spending cycles through local economies, generating business sales and supporting jobs and income. In 2017, the National Park System received an estimated 331 million recreation visits. Visitors to National Parks spent an estimated \\$18.2 billion in local gateway regions (defined as communities within 60 miles of a park). The contribution of this spending to the national economy was 306 thousand jobs, \\$11.9 billion in labor income, \\$20.3 billion in value added, and \\$35.8 billion in economic output. The lodging sector saw the highest direct contributions with \\$5.5 billion in economic output directly contributed to local gateway economies nationally. The sector with the next greatest direct contributions was the restaurants and bars sector, with \\$3.7 billion in economic output directly contributed to local gateway economies nationally. Results from the Visitor Spending Effects report series are available online via an interactive tool. Users can view year-by-year trend data and explore current year visitor spending, jobs, labor income, value added, and economic output effects by sector for national, state, and local economies. This interactive tool is available at https://www.nps.gov/subjects/socialscience/vse.htm.

  6. Importance of initial buoyancy field on evolution of mantle thermal structure: Implications of surface boundary conditions

    Directory of Open Access Journals (Sweden)

    Petar Glišović

    2015-01-01

    Full Text Available Although there has been significant progress in the seismic imaging of mantle heterogeneity, the outstanding issue that remains to be resolved is the unknown distribution of mantle temperature anomalies in the distant geological past that give rise to the present-day anomalies inferred by global tomography models. To address this question, we present 3-D convection models in compressible and self-gravitating mantle initialised by different hypothetical temperature patterns. A notable feature of our forward convection modelling is the use of self-consistent coupling of the motion of surface tectonic plates to the underlying mantle flow, without imposing prescribed surface velocities (i.e., plate-like boundary condition. As an approximation for the surface mechanical conditions before plate tectonics began to operate we employ the no-slip (rigid boundary condition. A rigid boundary condition demonstrates that the initial thermally-dominated structure is preserved, and its geographical location is fixed during the evolution of mantle flow. Considering the impact of different assumed surface boundary conditions (rigid and plate-like on the evolution of thermal heterogeneity in the mantle we suggest that the intrinsic buoyancy of seven superplumes is most-likely resolved in the tomographic images of present-day mantle thermal structure. Our convection simulations with a plate-like boundary condition reveal that the evolution of an initial cold anomaly beneath the Java-Indonesian trench system yields a long-term, stable pattern of thermal heterogeneity in the lowermost mantle that resembles the present-day Large Low Shear Velocity Provinces (LLSVPs, especially below the Pacific. The evolution of subduction zones may be, however, influenced by the mantle-wide flow driven by deeply-rooted and long-lived superplumes since Archean times. These convection models also detect the intrinsic buoyancy of the Perm Anomaly that has been identified as a unique

  7. An exploratory study of the local socio-economic effects of Sizewell B

    International Nuclear Information System (INIS)

    1982-12-01

    This Sizewell B study involved five main tasks: (i) to provide broad estimates of the temporary and permanent accommodation requirements of the proposed Sizewell B workforce and families and the likely level of local supply of accommodation; (ii) to provide broad estimates of the requirements for school places of the accompanied workforce and the likely local supply of such places; (iii) to assess further the wider employment effects of the proposed development on local firms, particularly as potential suppliers of goods and services; (iv) to conduct further studies of the expenditure patterns of power station employees; and (v) to incorporate where relevant the likely effects of a policy of double day shift work (in power station construction) into the predictions. Results of the study are reported. (author)

  8. Locality effects on bifurcation paradigm of L-H transition in tokamak plasmas

    Directory of Open Access Journals (Sweden)

    Boonyarit Chatthong

    2015-12-01

    Full Text Available The locality effects on bifurcation paradigm of L-H transition phenomenon in magnetic confinement plasmas are investigated. One dimensional thermal transport equation with both neoclassical and anomalous transports effects included is considered, where a flow shear due to pressure gradient component is included as a transport suppression mechanism. Three different locally driven models for anomalous transport are considered, including a constant transport model, pressure gradient driven transport model, and critical pressure gradient threshold transport model. Local stability analysis shows that the transition occurs at a threshold flux with hysteresis nature only if ratio of anomalous strength over neoclassical transport exceeds a critical value. The depth of the hysteresis loop depends on both neoclassical and anomalous transports, as well as the suppression strength. The reduction of the heat flux required to maintain H-mode can be as low as a factor of two, which is similar to experimental evidence.

  9. Effective Communication as Catalyst of Developmental Local Government and Rural Development amid Threats of Overpopulation

    Directory of Open Access Journals (Sweden)

    Naledzani Rasila

    2012-09-01

    Full Text Available South Africa’s population has risen from 40.5 million in 1996  to 44.8 million in 2001 and to 51.77 in 2011. Africans are in majority making 79.2% of the whole population. About 22.3% of blacks have received no schooling with the unemployment rate of the blacks at 28.1%. Most of these unemployed and uneducated blacks are found in rural areas. This compelled government to introduce Developmental Local government. Developmental Local government refers to the layer of public service that has the capacity to deliver and account to the people in a responsive, accountable, and efficient manner. It is also described as a sphere that encourages community participation in matters of governance and developmental initiatives. However, Developmental Local government is hindered by continuous growth of population which is likely to lead to overpopulation. Overpopulation is characterised by lack of basic resources such as water and  food. Developmental Local government on the other hand is expected to deliver on these needs. Lack of fulfilment of goals of Developmental Local government is attributed to lack of effective communication between local government and community members. Although population growth is not attributed only to high birth rate, governments around the continent have introduced measures to encourage healthy reproductive life. However, this needs community members that are self-motivated to be active participants in government initiatives. This is not achievable as there is an indication of lack of effective communication. This paper’s main focus is the provision of effective communication model at local sphere which will see community members working together with government on matters of their own development including initiatives  to preserve limited resources amid the challenges of overpopulation. This paper is based on the qualitative study on effectiveness of communication in Mutale local municipality on the enhancement of

  10. Effectiveness of a locally produced RUTF for the treatment of Acute Malnutrition in Vietnam

    International Nuclear Information System (INIS)

    Nguyen, Marie; Berger, Jacques; Wieringa, Frank; Tran, Thuy Nga; Do, Thi Bao Hoa; Nguyen, Hong Minh; Mathisen, Roger

    2014-01-01

    Full text: Background and Objectives: After an assessment of peanut-based RUTF in Cambodia found low acceptability rates, the National Institute of Nutrition Vietnam, UNICEF and the Institut de Recherche pour le Développement started in 2009 to work on a locally produced RUTF, adapted to local taste and preference for the treatment of severe acute malnutrition (SAM). In 2010, the newly developed product was found to be highly acceptable, but impact on weight gain needed to be proven. Therefore, this study was conducted to assess the effectiveness of the local RUTF on weight gain and recovery rate using the RUTF in a home based treatment of acute malnutrition. Methods and Design: The study was a randomized intervention trial in 150 children, aged 6-59 months, with SAM or moderate acute malnutrition (MAM) to test the effectiveness of the local RUTF (bar) against a standard RUTF (peanut-based paste). The study was done as a community-based intervention trial in Kon Tum province (Central Highlands region), Vietnam, where an Integrated Management of Acute Malnutrition programs (IMAM) program was just being introduced. Results: Children consumed 92% and 70% of the offered local RUTF and standard RUTF respectively, underlining the problems with a peanut-based RUTF in SE Asia. Nutritional status of the children was significantly improved after the 8 weeks intervention. Mean weight gain with the standard RUTF and the local RUTF was 2.97 (± 1.57) g/kg/d and 2.52 (± 1.23) g/kg/d respectively. Also, both RUTFs improved significantly height and HAZ-scores, with a mean height gain of 22.4 (±18.7) mm and 32.3 (±36.3) mm for respectively standard and local RUTF. The recovery rate from acute malnutrition with RUTFs as home treatment was 70.8%, and not different between the 2 interventions. Conclusions: The local RUTF was as effective as the standard RUTF on the treatment of acute malnutrition, whereas acceptability was higher. The local RUTF can be successfully used in the

  11. The effect of local cryotherapy on subjective and objective recovery characteristics following an exhaustive jump protocol.

    Science.gov (United States)

    Hohenauer, Erich; Clarys, Peter; Baeyens, Jean-Pierre; Clijsen, Ron

    2016-01-01

    The purpose of this controlled trial was to investigate the effects of a single local cryotherapy session on the recovery characteristics over a period of 72 hours. Twenty-two young and healthy female (n=17; mean age: 21.9±1.1 years) and male (n=5;mean age: 25.4±2.8 years) adults participated in this study. Following an exhaustive jump protocol (3×30 countermovement jumps), half of the participants received either a single local cryotherapy application (+8°C) or a single local thermoneutral application (+32°C) of 20-minute duration using two thigh cuffs. Subjective measures of recovery (delayed-onset muscle soreness and ratings of perceived exertion) and objective measures of recovery (vertical jump performance and peak power output) were assessed immediately following the postexercise applications (0 hours) and at 24 hours, 48 hours, and 72 hours after the jump protocol. Local cryotherapy failed to significantly affect any subjective recovery variable during the 72-hour recovery period (P>0.05). After 72 hours, the ratings of perceived exertion were significantly lower in the thermoneutral group compared to that in the cryotherapy group (P=0.002). No significant differences were observed between the cryotherapy and the thermoneutral groups with respect to any of the objective recovery variables. In this experimental study, a 20-minute cryotherapy cuff application failed to demonstrate a positive effect on any objective measures of recovery. The effects of local thermoneutral application on subjective recovery characteristics were superior when compared to the effects of local cryotherapy application at 72 hours postapplication.

  12. Prevailing negative soil biota effect and no evidence for local adaptation in a widespread Eurasian grass.

    Directory of Open Access Journals (Sweden)

    Viktoria Wagner

    2011-03-01

    Full Text Available Soil biota effects are increasingly accepted as an important driver of the abundance and distribution of plants. While biogeographical studies on alien invasive plant species have indicated coevolution with soil biota in their native distribution range, it is unknown whether adaptation to soil biota varies among populations within the native distribution range. The question of local adaptation between plants and their soil biota has important implications for conservation of biodiversity and may justify the use of seed material from local provenances in restoration campaigns.We studied soil biota effects in ten populations of the steppe grass Stipa capillata from two distinct regions, Europe and Asia. We tested for local adaptation at two different scales, both within (ca. 10-80 km and between (ca. 3300 km regions, using a reciprocal inoculation experiment in the greenhouse for nine months. Generally, negative soil biota effects were consistent. However, we did not find evidence for local adaptation: both within and between regions, growth of plants in their 'home soil' was not significantly larger relative to that in soil from other, more distant, populations.Our study suggests that negative soil biota effects can prevail in different parts of a plant species' range. Absence of local adaptation points to the possibility of similar rhizosphere biota composition across populations and regions, sufficient gene flow to prevent coevolution, selection in favor of plasticity, or functional redundancy among different soil biota. From the point of view of plant--soil biota interactions, our findings indicate that the current practice of using seeds exclusively from local provenances in ecosystem restoration campaigns may not be justified.

  13. AN INVESTIGATION OF LOCAL EFFECTS ON SURFACE WARMING WITH GEOGRAPHICALLY WEIGHTED REGRESSION (GWR

    Directory of Open Access Journals (Sweden)

    Y. Xue

    2012-07-01

    Full Text Available Urban warming is sensitive to the nature (thermal properties, including albedo, water content, heat capacity and thermal conductivity and the placement (surface geometry or urban topography of urban surface. In the literature the spatial dependence and heterogeneity of urban thermal landscape is widely observed based on thermal infrared remote sensing within the urban environment. Urban surface warming is conceived as a big contribution to urban warming, the study of urban surface warming possesses significant meaning for probing into the problem of urban warming.The urban thermal landscape study takes advantage of the continuous surface derived from thermal infrared remote sensing at the landscape scale, the detailed variation of local surface temperature can be measured and analyzed through the systematic investigation. At the same time urban environmental factors can be quantified with remote sensing and GIS techniques. This enables a systematic investigation of urban thermal landscape with a link to be established between local environmental setting and surface temperature variation. The goal of this research is utilizing Geographically Weighted Regression (GWR to analyze the spatial relationship between urban form and surface temperature variation in order to clarify the local effects on surface warming, moreover to reveal the possible dynamics in the local influences of environmental indicators on the variation of local surface temperature across space and time. In this research, GWR analysis proved that the spatial variation in relationships between environmental setting and surface temperature was significant with Monte Carlo significance test and distinctive in day-night change. Comparatively, GWR facilitated the site specific investigation based on local statistical technique. The inference based on GWR model provided enriched information regarding the spatial variation of local environment effect on surface temperature variation which

  14. Effects on functional outcome after IORT-containing multimodality treatment for locally advanced primary and locally recurrent rectal cancer

    International Nuclear Information System (INIS)

    Mannaerts, Guido H.H.; Rutten, Harm J.T.; Martijn, Hendrik; Hanssens, Patrick E.J.; Wiggers, Theo

    2002-01-01

    Purpose: In the treatment of patients with locally advanced primary or locally recurrent rectal cancer, much attention is focused on the oncologic outcome. Little is known about the functional outcome. In this study, the functional outcome after a multimodality treatment for locally advanced primary and locally recurrent rectal cancer is analyzed. Methods and Materials: Between 1994 and 1999, 55 patients with locally advanced primary and 66 patients with locally recurrent rectal cancer were treated with high-dose preoperative external beam irradiation, followed by extended surgery and intraoperative radiotherapy. To assess long-term functional outcome, all patients still alive (n = 97) were asked to complete a questionnaire regarding ongoing morbidity, as well as functional and social impairment. Seventy-six of the 79 patients (96%) returned the questionnaire. The median follow-up was 14 months (range: 4-60 months). Results: The questionnaire revealed fatigue in 44%, perineal pain in 42%, radiating pain in the leg(s) in 21%, walking difficulties in 36%, and voiding dysfunction in 42% of the patients as symptoms of ongoing morbidity. Functional impairment consisted of requiring help with basic activities in 15% and sexual inactivity in 56% of the respondents. Social handicap was demonstrated by loss of former lifestyle in 44% and loss of professional occupation in 40% of patients. Conclusions: As a result of multimodality treatment, the majority of these patients have to deal with long-term physical morbidity, the need for help with daily care, and considerable social impairment. These consequences must be weighed against the chance of cure if the patient is treated and the disability eventually caused by uncontrolled tumor progression if the patient is not treated. These potential drawbacks should be discussed with the patient preoperatively and taken into account when designing a treatment strategy

  15. Effectiveness of new vibration delivery system on pain associated with injection of local anesthesia in children

    Directory of Open Access Journals (Sweden)

    Mangalampally Shilpapriya

    2015-01-01

    Full Text Available Aim: Pain is highly subjective and it is neurologically proven that stimulation of larger diameter fibers - e.g., using appropriate coldness, warmth, rubbing, pressure or vibration - can close the neural "gate" so that the central perception of itch and pain is reduced. This fact is based upon "gate control" theory of Melzack and Wall. The present study was carried out to investigate the effects of vibration stimuli on pain experienced during local anesthetic injections. Materials and Methods: Thirty patients aged 6-12 years old of both the genders with Frankel′s behavior rating scale as positive and definitely positive requiring bilateral local anesthesia injections for dental treatment were included in the split-mouth cross over design. Universal pain assessment tool was used to assess the pain with and without vibration during the administration of local anesthesia and the results obtained were tabulated and statistically analyzed. Results: Local anesthetic administration with vibration resulted in significantly less pain (P = 0.001 compared to the injections without the use of vibe. Conclusion: The results suggest that vibration can be used as an effective method to decrease pain during dental local anesthetic administration.

  16. Effectiveness of new vibration delivery system on pain associated with injection of local anesthesia in children.

    Science.gov (United States)

    Shilpapriya, Mangalampally; Jayanthi, Mungara; Reddy, Venumbaka Nilaya; Sakthivel, Rajendran; Selvaraju, Girija; Vijayakumar, Poornima

    2015-01-01

    Pain is highly subjective and it is neurologically proven that stimulation of larger diameter fibers - e.g., using appropriate coldness, warmth, rubbing, pressure or vibration - can close the neural "gate" so that the central perception of itch and pain is reduced. This fact is based upon "gate control" theory of Melzack and Wall. The present study was carried out to investigate the effects of vibration stimuli on pain experienced during local anesthetic injections. Thirty patients aged 6-12 years old of both the genders with Frankel's behavior rating scale as positive and definitely positive requiring bilateral local anesthesia injections for dental treatment were included in the split-mouth cross over design. Universal pain assessment tool was used to assess the pain with and without vibration during the administration of local anesthesia and the results obtained were tabulated and statistically analyzed. Local anesthetic administration with vibration resulted in significantly less pain (P = 0.001) compared to the injections without the use of vibe. The results suggest that vibration can be used as an effective method to decrease pain during dental local anesthetic administration.

  17. Optimal Audiovisual Integration in the Ventriloquism Effect But Pervasive Deficits in Unisensory Spatial Localization in Amblyopia.

    Science.gov (United States)

    Richards, Michael D; Goltz, Herbert C; Wong, Agnes M F

    2018-01-01

    Classically understood as a deficit in spatial vision, amblyopia is increasingly recognized to also impair audiovisual multisensory processing. Studies to date, however, have not determined whether the audiovisual abnormalities reflect a failure of multisensory integration, or an optimal strategy in the face of unisensory impairment. We use the ventriloquism effect and the maximum-likelihood estimation (MLE) model of optimal integration to investigate integration of audiovisual spatial information in amblyopia. Participants with unilateral amblyopia (n = 14; mean age 28.8 years; 7 anisometropic, 3 strabismic, 4 mixed mechanism) and visually normal controls (n = 16, mean age 29.2 years) localized brief unimodal auditory, unimodal visual, and bimodal (audiovisual) stimuli during binocular viewing using a location discrimination task. A subset of bimodal trials involved the ventriloquism effect, an illusion in which auditory and visual stimuli originating from different locations are perceived as originating from a single location. Localization precision and bias were determined by psychometric curve fitting, and the observed parameters were compared with predictions from the MLE model. Spatial localization precision was significantly reduced in the amblyopia group compared with the control group for unimodal visual, unimodal auditory, and bimodal stimuli. Analyses of localization precision and bias for bimodal stimuli showed no significant deviations from the MLE model in either the amblyopia group or the control group. Despite pervasive deficits in localization precision for visual, auditory, and audiovisual stimuli, audiovisual integration remains intact and optimal in unilateral amblyopia.

  18. Local hemostatic matrix for endoscope-assisted removal of intracerebral hemorrhage is safe and effective

    Directory of Open Access Journals (Sweden)

    Hui-Tzung Luh

    2018-01-01

    Conclusion: This study shows that local application of FloSeal Hemostatic Matrix is safe and effective for hemostasis during MIE evacuation of ICH. In our experience, this shortens the operation time, especially in cases with intraoperative bleeding. A large, prospective, randomized trial is needed to confirm the findings.

  19. The role of Urbis' noise and noise effects maps in local policy

    NARCIS (Netherlands)

    Borst, H.C.

    2001-01-01

    An important aspect of the EU noise policy is mapping of noise and noise effects and the formulation of noise action plans. In the Netherlands, due to the new policy on noise (MIG), the municipalities will be responsible for the formulation of a local noise policy. An instrument for the assessment

  20. Many-body localization proximity effects in platforms of coupled spins and bosons

    Science.gov (United States)

    Marino, J.; Nandkishore, R. M.

    2018-02-01

    We discuss the onset of many-body localization in a one-dimensional system composed of a XXZ quantum spin chain and a Bose-Hubbard model linearly coupled together. We consider two complementary setups, depending whether spatial disorder is initially imprinted on spins or on bosons; in both cases, we explore the conditions for the disordered portion of the system to localize by proximity of the other clean half. Assuming that the dynamics of one of the two parts develops on shorter time scales than the other, we can adiabatically eliminate the fast degrees of freedom, and derive an effective Hamiltonian for the system's remainder using projection operator techniques. Performing a locator expansion on the strength of the many-body interaction term or on the hopping amplitude of the effective Hamiltonian thus derived, we present results on the stability of the many-body localized phases induced by proximity effect. We also briefly comment on the feasibility of the proposed model through modern quantum optics architectures, with the long-term perspective to realize experimentally, in composite open systems, Anderson or many-body localization proximity effects.

  1. Possible effect of the local terrain on the Australian fifth-force measurement

    International Nuclear Information System (INIS)

    Bartlett, D.F.; Tew, W.L.

    1989-01-01

    We believe that the local topography can account for most of the positive evidence for non-Newtonian gravity recently reported by Stacey and co-workers. We show that the Hilton mine site in Queensland, Australia, is effectively in a valley and speculate on how this feature could have been missed in the original analysis

  2. An Empirical Study on Effective Tax Rate and CEO Promotion: Evidence from Local SOEs in China

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2018-06-01

    Full Text Available This paper investigates the influence of effective tax payment on the CEO promotion in local State Owned Enterprise (SOE in China. Based on the analysis of listed local SOEs in China from 2004 to 2010, this paper tests the relationship between CEO promotion and tax payment. In addition, the moderating effect of pyramid layer is tested. This paper finds that there is a significant positive relationship between Effective Tax Rate (ETR and CEO promotion, which suggests that CEOs may be aggressive in tax payment to please the local governments, who ultimately own the local SOEs. The current paper also finds that the relationship between ETR and CEO promotion is weakened as pyramid layers increase. Our conclusions enrich the literature on CEO turnover and the role of pyramid structure. The conclusions are also helpful for the SOEs’ reform in China and other developing countries. First, this paper is among the first to investigate the relationship between ETR and CEO turnover. Second, this paper highlights the function of pyramid structure in mitigating government intervention. Third, this paper also adds to the research on effective tax.

  3. Non-local effect in Brillouin optical time-domain analyzer based on Raman amplification

    International Nuclear Information System (INIS)

    Jia Xinhong; Rao Yunjiang; Wang Zinan; Zhang Weili; Ran Zengling; Deng Kun; Yang Zixin

    2012-01-01

    Compared with conventional Brillouin optical time-domain analyzer (BOTDA), the BOTDA based on Raman amplification allows longer sensing range, higher signal-to-noise ratio and higher measurement accuracy. However, the non-local effect induced by pump depletion significantly restricts the probe optical power injected to sensing fiber, thereby limiting the further extension for sensing distance. In this paper, the coupled equations including the interaction of probe light, Brillouin and Raman pumps are applied to the study on the non-local characteristics of BOTDA based on Raman amplification. The results show that, the system error induced by non-local effect worsens with increased powers of probe wave and Raman pump. The frequency-division-multiplexing (cascading the fibers with various Brillouin frequency shifts) and time-division-multiplexing (modulating both of the Brillouin pump and probe lights) technologies are efficient approaches to suppress the non-local effect, through shortening the effective interaction range between Brillouin pump and probe lights. (authors)

  4. An Evaluation of The Effects of Local Mix Design on the ...

    African Journals Online (AJOL)

    This is a report on an evaluation of the effect of local mix design of concrete on its compressive strength. In order to accomplish this research work, field survey was first undertaken with a well-structured questionnaire. This questionnaire was administered to the respondents who are directly involved in concrete production.

  5. Dose-Effect Relationship in Chemoradiotherapy for Locally Advanced Rectal Cancer

    DEFF Research Database (Denmark)

    Jakobsen, Anders; Ploen, John; Vuong, Té

    2012-01-01

    PURPOSE: Locally advanced rectal cancer represents a major therapeutic challenge. Preoperative chemoradiation therapy is considered standard, but little is known about the dose-effect relationship. The present study represents a dose-escalation phase III trial comparing 2 doses of radiation...

  6. Operationalising an effective monitoring and evaluation system for local government: Considerations for best practice

    Directory of Open Access Journals (Sweden)

    Paul Kariuki

    2017-11-01

    Conclusion: The article concluded that effective monitoring and evaluation in local government that is responsive to citizens’ needs is a non-negotiable imperative for government. It recommended that municipalities be adequately resourced with competent monitoring and evaluation human personnel. This is important for strengthening their capacity to deliver efficient monitoring and evaluation services.

  7. 15 CFR 8a.535 - Effect of state or local law or other requirements.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Effect of state or local law or other requirements. 8a.535 Section 8a.535 Commerce and Foreign Trade Office of the Secretary of Commerce... are not imposed upon members of the other sex. (b) Benefits. A recipient that provides any...

  8. 13 CFR 113.535 - Effect of state or local law or other requirements.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Effect of state or local law or other requirements. 113.535 Section 113.535 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... obligation to comply with §§ 113.500 through 113.550 is not obviated or alleviated by the existence of any...

  9. Order- N Green's Function Technique for Local Environment Effects in Alloys

    DEFF Research Database (Denmark)

    Abrikosov, I. A.; Niklasson, A. M. N.; Simak, S. I.

    1996-01-01

    We have developed a new approach to the calculations of ground state properties of large crystalline systems with arbitrary atomic configurations based on a Green's function technique in conjunction with a self-consistent effective medium for the underlying randomly occupied lattice. The locally...

  10. The role of localization within the vortex picture of the fractional quantum Hall effect

    International Nuclear Information System (INIS)

    Bruus, H.; Hansen, O.P.; Hansen, E.B.

    1988-01-01

    Plateau formation in the fractional quantum Hall effect is shown to arise because, by pinning of vortices in the incompressible electron liquid, the canonical filling factor can be stationarily maintained in the interconnected region between the vortices. The crucial role of localization is demonstrated by considering the idealized limit where pinning centres are absent. (orig.)

  11. Effects of Storage Time on the Quality of Local Chicken Meat ...

    African Journals Online (AJOL)

    An experiment was carried out to investigate the proximate composition and effects of aging time on local chicken meat quality. For proximate analysis, 24 male and 24 female breast, thigh and drumstick samples from one half of the carcass were skinned, de-boned and frozen at -20oC. The samples were minced through a ...

  12. Effect of tumor dose, volume and overall treatment time on local control after radiochemotherapy including MRI guided brachytherapy of locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Tanderup, Kari; Fokdal, Lars Ulrik; Sturdza, Alina

    2016-01-01

    -center patient series (retroEMBRACE). Materials and methods This study analyzed 488 locally advanced cervical cancer patients treated with external beam radiotherapy ± chemotherapy combined with IGABT. Brachytherapy contouring and reporting was according to ICRU/GEC-ESTRO recommendations. The Cox Proportional...... Hazards model was applied to analyze the effect on local control of dose-volume metrics as well as overall treatment time (OTT), dose rate, chemotherapy, and tumor histology. Results With a median follow up of 46 months, 43 local failures were observed. Dose (D90) to the High Risk Clinical Target Volume...

  13. Influence of thermal buoyancy on vertical tube bundle thermal density head predictions under transient conditions

    International Nuclear Information System (INIS)

    Lin, H.C.; Kasza, K.E.

    1984-01-01

    The thermal-hydraulic behavior of an LMFBR system under various types of plant transients is usually studied using one-dimensional (1-D) flow and energy transport models of the system components. Many of the transient events involve the change from a high to a low flow with an accompanying change in temperature of the fluid passing through the components which can be conductive to significant thermal bouyancy forces. Thermal bouyancy can exert its influence on system dynamic energy transport predictions through alterations of flow and thermal distributions which in turn can influence decay heat removal, system-response time constants, heat transport between primary and secondary systems, and thermal energy rejection at the reactor heat sink, i.e., the steam generator. In this paper the results from a comparison of a 1-D model prediction and experimental data for vertical tube bundle overall thermal density head and outlet temperature under transient conditions causing varying degrees of thermal bouyancy are presented. These comparisons are being used to generate insight into how, when, and to what degree thermal buoyancy can cause departures from 1-D model predictions

  14. Magma buoyancy and volatile ascent driving autocyclic eruptivity at Hekla Volcano (Iceland)

    Science.gov (United States)

    Hautmann, Stefanie; Sacks, I. Selwyn; Linde, Alan T.; Roberts, Matthew J.

    2017-09-01

    Volcanic eruptions are typically accompanied by ground deflation due to the withdrawal of magma from depth and its effusion at the surface. Here, based on continuous high-resolution borehole strain data, we show that ground deformation was absent during the major effusion phases of the 1991 and 2000 eruptions of Hekla Volcano, Iceland. This lack of surface deformation challenges the classic model of magma intrusion/withdrawal as source for volcanic ground uplift/subsidence. We incorporate geodetic and geochemical observables into theoretical models of magma chamber dynamics in order to constrain quantitatively alternative co- and intereruptive physical mechanisms that govern magma propagation and system pressurization. We find the lack of surface deformation during lava effusion to be linked to chamber replenishment from below whilst magma migrates as a buoyancy-driven flow from the magma chamber towards the surface. We further demonstrate that intereruptive pressure build-up is likely to be generated by volatile ascent within the chamber rather than magma injection. Our model explains the persistent periodic eruptivity at Hekla throughout historic times with self-initiating cycles and is conceptually relevant to other volcanic systems.

  15. Suppression of atmospheric recycling of planets embedded in a protoplanetary disc by buoyancy barrier

    Science.gov (United States)

    Kurokawa, Hiroyuki; Tanigawa, Takayuki

    2018-06-01

    The ubiquity of super-Earths poses a problem for planet formation theory to explain how they avoided becoming gas giants. Rapid recycling of the envelope gas of planets embedded in a protoplanetary disc has been proposed to delay the cooling and following accretion of disc gas. We compare isothermal and non-isothermal 3D hydrodynamical simulations of the gas flow past a planet to investigate the influence on the feasibility of the recycling mechanism. Radiative cooling is implemented by using the β cooling model. We find that, in either case, gas enters the Bondi sphere at high latitudes and leaves through the midplane regions, or vice versa when disc gas rotates sub-Keplerian. However, in contrast to the isothermal case where the recycling flow reaches the deeper part of the envelope, the inflow is inhibited from reaching the deep envelope in the non-isothermal case. Once the atmosphere starts cooling, buoyant force prevents the high-entropy disc gas from intruding the low-entropy atmosphere. We suggest that the buoyancy barrier isolates the lower envelope from the recycling and allows further cooling, which may lead runaway gas accretion onto the core.

  16. Flow rate measurement of buoyancy-driven exchange flow by laser Doppler velocimeter

    International Nuclear Information System (INIS)

    Fumizawa, Motoo

    1993-01-01

    An experimental investigation was carried out for the buoyancy-driven exchange flow in a narrow vented cylinder concerning the air ingress process during a standing pipe rupture in a high-temperature gas-cooled reactor. In the present study, the evaluation method of exchange flow was developed by measuring the velocity distribution in the cylinder using a laser Doppler velocimeter. The experiments were performed under atmospheric pressure with nitrogen as a working fluid. Rayleigh numbers ranged from 2.0x10 4 to 2.1x10 5 . The exchange flow fluctuated irregularly with time and space in the cylinder. It was found that the exchange velocity distribution along the horizontal axis changed from one-hump to two-hump distribution with increasing Rayleigh number. In the case that the hemisphere wall was cooler than the heated disk, the volumetric exchange flow rate was smaller than that in the case where the hemisphere wall and the heated disk were at the same temperature. (author)

  17. Local radiolytic effectiveness of Auger electrons of iodine-125 in benzene-iodine solutions

    International Nuclear Information System (INIS)

    Uenak, P.; Uenak, T.

    1987-01-01

    High radiotoxicity of iodine-125 has been mainly attributed to the local radiolytic effects of Auger electrons on biological systems. In the present study, experimental and theoretical results are compared. The agreement between the experimental and theoretical results explains that the energy absorption of iodine aggregates has an important role in the radiolytic effectiveness of Auger electrons and iodine-125 in benzene-iodine solutions. (author) 18 refs.; 3 figs

  18. Cost-effectiveness of modern radiotherapy techniques in locally advanced pancreatic cancer.

    Science.gov (United States)

    Murphy, James D; Chang, Daniel T; Abelson, Jon; Daly, Megan E; Yeung, Heidi N; Nelson, Lorene M; Koong, Albert C

    2012-02-15

    Radiotherapy may improve the outcome of patients with pancreatic cancer but at an increased cost. In this study, the authors evaluated the cost-effectiveness of modern radiotherapy techniques in the treatment of locally advanced pancreatic cancer. A Markov decision-analytic model was constructed to compare the cost-effectiveness of 4 treatment regimens: gemcitabine alone, gemcitabine plus conventional radiotherapy, gemcitabine plus intensity-modulated radiotherapy (IMRT); and gemcitabine with stereotactic body radiotherapy (SBRT). Patients transitioned between the following 5 health states: stable disease, local progression, distant failure, local and distant failure, and death. Health utility tolls were assessed for radiotherapy and chemotherapy treatments and for radiation toxicity. SBRT increased life expectancy by 0.20 quality-adjusted life years (QALY) at an increased cost of $13,700 compared with gemcitabine alone (incremental cost-effectiveness ratio [ICER] = $69,500 per QALY). SBRT was more effective and less costly than conventional radiotherapy and IMRT. An analysis that excluded SBRT demonstrated that conventional radiotherapy had an ICER of $126,800 per QALY compared with gemcitabine alone, and IMRT had an ICER of $1,584,100 per QALY compared with conventional radiotherapy. A probabilistic sensitivity analysis demonstrated that the probability of cost-effectiveness at a willingness to pay of $50,000 per QALY was 78% for gemcitabine alone, 21% for SBRT, 1.4% for conventional radiotherapy, and 0.01% for IMRT. At a willingness to pay of $200,000 per QALY, the probability of cost-effectiveness was 73% for SBRT, 20% for conventional radiotherapy, 7% for gemcitabine alone, and 0.7% for IMRT. The current results indicated that IMRT in locally advanced pancreatic cancer exceeds what society considers cost-effective. In contrast, combining gemcitabine with SBRT increased clinical effectiveness beyond that of gemcitabine alone at a cost potentially acceptable by

  19. The Effect of Cigarette Taxation on Prices: An Empirical Analysis Using Local-Level Data

    Science.gov (United States)

    2012-01-01

    index (COLI) and from the Tax Burden on Tobacco ( TBT ) to measure the relative effects of city, county and state excise cigarette taxation on cigarette...Researchers Association (ACCRA) cost of living index (COLI) and from the Tax Burden on Tobacco ( TBT ) to measure the relative effects of city, county and...Geographic Information Systems (GIS) software. In addition to the local-level data, we utilize the Tax Burden on Tobacco ( TBT ) dataset to analyze

  20. The local economic and social effects of power station siting: anticipated, demonstrated and perceived

    International Nuclear Information System (INIS)

    Glasson, J.

    1980-01-01

    The paper discusses the economic and social effects of power station siting at a local level using material based on the interim research findings from a project commissioned by the Central Electricity Generating Board. The cases for and against power station development are outlined and a review of the actual economic and social effects is presented, drawn from a study of a conventional power station at Drax and a nuclear power station at Sizewell. (U.K.)

  1. QUALITY, EFFECTIVENESS AND MANAGEMENT INFORMATION SYSTEMS PERFORMANCE OF LOCAL TREASURIES BUDGET ACCOUNTING

    OpenAIRE

    Biljana Tešić

    2011-01-01

    The role of management information systems (MIS) of local treasuries budget accounting is to provide qualitative information support to management in process of decision making and to provide effective managing of key processes of budget accounting, in accordance with requests of management on all levels of decision making. From the aspect of effectiveness and request for quality, in accordance with request of users and defined system goals, this research includes the analysis of characterist...

  2. Contracting out local road and park services: Economic effects and their strategic, contractual, and competitive conditions

    DEFF Research Database (Denmark)

    Lindholst, Andrej Christian; Petersen, Ole Helby; Houlberg, Kurt

    2018-01-01

    such as markets, contracts, municipal strategies and contracting history influence these outcomes. Drawing on original survey data from Danish municipalities, we find that competitive tendering has on average reduced costs. Further analysis shows that savings are not associated with lower quality, thus indicating......The economic rationale for contracting out local services is increasingly contested by empirical research. This article aims to contribute to this literature, first by scrutinising the economic effects of contracting out in local road and park services and, second, by exploring how characteristics...... realise larger savings, whereas the characteristics of markets and contracts do not seem to explain variations in cost savings....

  3. Effects of weak localization in quasi-one-dimensional electronic system over liquid helium

    CERN Document Server

    Kovdrya, Y Z; Gladchenko, S P

    2001-01-01

    One measured rho sub x sub x magnetoresistance of a quasi-one-dimensional electronic system over liquid helium within gas scattering range (1.3-2.0 K temperature range). It is shown that with increase of magnetic field the magnetoresistance is reduced at first and them upon passing over minimum it begins to increase from rho sub x sub x approx B sup 2 law. One anticipated that the negative magnetoresistance detected in the course of experiments resulted from the effects of weak localization. The experiment results are in qualitative conformity with the theoretical model describing processes of weak localization in single-dimensional nondegenerate electronic systems

  4. Localization effects in the tunnel barriers of phosphorus-doped silicon quantum dots

    Directory of Open Access Journals (Sweden)

    T. Ferrus

    2012-06-01

    Full Text Available We have observed a negative differential conductance with singular gate and source-drain bias dependences in a phosphorus-doped silicon quantum dot. Its origin is discussed within the framework of weak localization. By measuring the current-voltage characteristics at different temperatures as well as simulating the tunneling rates dependences on energy, we demonstrate that the presence of shallow energy defects together with an enhancement of localization satisfactory explain our observations. Effects observed in magnetic fields are also discussed.

  5. Atomic size and local order effects on the high temperature strength of binary Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Abaspour, Saeideh, E-mail: s.abaspour78@gmail.com [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia); Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), The University of Queensland (Australia); Zambelli, Victor [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia); Dargusch, Matthew [Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), The University of Queensland (Australia); Cáceres, Carlos H. [ARC-Centre of Excellence for Design in Light Metals, Materials Engineering, School of Engineering, The University of Queensland, Brisbane QLD 4072 (Australia)

    2016-09-15

    The solid solution strengthening introduced by Ca (0.6 and 0.9 at%) and Sn 0.5–2.5 at%) was studied through tensile, compression and stress relaxation tests at room temperature, 373 K (100 °C) and 453 K (180 °C) on solution heat-treated and quenched specimens and compared with existing data for binary alloys containing Ca, Sn, Y, Gd, Nd, Zn and Al as well as for AZ91 alloy. At room temperature the solution-hardening rate introduced by Ca and Sn was much higher than that of Al, matching those of Y, Gd and Zn. Calcium also reduced the tension/compression asymmetry. At high temperature Ca effectively prevented stress relaxation, nearly matching Y, Gd and Nd. Tin was less effective, but still outperformed Al and AZ91 at low stresses. The effects at room and high temperature introduced by Ca and Sn appeared consistent with the presence of short-range order, in line with those introduced by Y, Nd, Gd and Zn. The larger than Mg atom size of Ca, Nd, Gd and Y can be expected to intensify the local order by strengthening the atomic bonds through its effects on the local electron density, accounting for their greater strengthening at high temperature. For given difference in atomic size, the effects on the local order are expected to be lesser for smaller sized atoms like Sn and Zn, hence their more subdued effects.

  6. Cost-effectiveness of carbon ion radiation therapy for locally recurrent rectal cancer

    International Nuclear Information System (INIS)

    Mobaraki, A.; Ohno, Tatsuya; Sakurai, Hideyuki; Nakano, Takashi; Yamada Shigeru

    2010-01-01

    The aim of this study was to evaluate the cost-effectiveness of carbon ion radiotherapy compared with conventional multimodality therapy in the treatment of patients with locally recurrent rectal cancer. Direct costs for diagnosis, recurrent treatment, follow-up, visits, supportive therapy, complications, and admission were computed for each individual using a sample of 25 patients presenting with local recurrent rectal cancer at the National Institute of Radiological Science (NIRS) and Gunma University Hospital (GUH). Patients received only radical surgery for primary rectal adenocarcinoma and had isolated unresectable pelvic recurrence. Fourteen and 11 patients receiving treatment for the local recurrence between 2003 and 2005 were followed retrospectively at NIRS and GUH, respectively. Treatment was carried out with carbon ion radiotherapy (CIRT) alone at NIRS, while multimodality therapy including three-dimensional conformal radiotherapy, chemotherapy, and hyperthermia was performed at GUH. The 2-year overall survival rate was 85% and 55% for CIRT and multimodality treatment, respectively. The mean cost was 4803946 yen for the CIRT group and 4611100 yen for the multimodality treatment group. The incremental cost-effectiveness ratio for CIRT was 6428 yen per 1% increase in survival. The median duration of total hospitalization was 37 days for CIRT and 66 days for the multimodality treatment group. In conclusion, by calculating all direct costs, CIRT was found to be a potential cost effective treatment modality as compared to multimodality treatment for locally recurrent rectal cancer. (author)

  7. Unconventional scaling of the anomalous Hall effect accompanying electron localization correction in the dirty regime

    KAUST Repository

    Lu, Y. M.

    2013-03-05

    Scaling of the anomalous Hall conductivity to longitudinal conductivity σAH∝σ2xx has been observed in the dirty regime of two-dimensional weak and strong localization regions in ultrathin, polycrystalline, chemically disordered, ferromagnetic FePt films. The relationship between electron transport and temperature reveals a quantitatively insignificant Coulomb interaction in these films, while the temperature dependent anomalous Hall conductivity experiences quantum correction from electron localization. At the onset of this correction, the low-temperature anomalous Hall resistivity begins to be saturated when the thickness of the FePt film is reduced, and the corresponding Hall conductivity scaling exponent becomes 2, which is above the recent unified theory of 1.6 (σAH∝σ1.6xx). Our results strongly suggest that the correction of the electron localization modulates the scaling exponent of the anomalous Hall effect.

  8. Probing Anderson localization of light by weak non-linear effects

    International Nuclear Information System (INIS)

    Sperling, T; Bührer, W; Maret, G; Ackermann, M; Aegerter, C M

    2014-01-01

    Breakdown of wave transport due to strong disorder is a universal phenomenon known as Anderson localization (AL). It occurs because of the macroscopic population of reciprocal multiple scattering paths, which in three dimensional systems happens at a critical scattering strength. Intensities on these random loops should thus be highly increased relative to those of a diffusive sample. In order to highlight localized modes of light, we exploit the optical nonlinearities of TiO 2 . Power dependent and spectrally resolved time of flight distribution measurements in transmission through slabs of TiO 2 powders at various turbidities reveal that mostly long loops are affected by nonlinearities and that the deviations from diffusive transport observed at long times are due to these localized modes. Our data are a first step in the experimental investigation of the interplay between nonlinear effects and AL in 3D. (fast track communication)

  9. Effect of the interface resistance in non-local Hanle measurements

    International Nuclear Information System (INIS)

    Villamor, Estitxu; Hueso, Luis E.; Casanova, Fèlix

    2015-01-01

    We use lateral spin valves with varying interface resistance to measure non-local Hanle effect in order to extract the spin-diffusion length of the non-magnetic channel. A general expression that describes spin injection and transport, taking into account the influence of the interface resistance, is used to fit our results. Whereas the fitted spin-diffusion length value is in agreement with the one obtained from standard non-local measurements in the case of a finite interface resistance, in the case of transparent contacts a clear disagreement is observed. The use of a corrected expression, recently proposed to account for the anisotropy of the spin absorption at the ferromagnetic electrodes, still yields a deviation of the fitted spin-diffusion length which increases for shorter channel distances. This deviation shows how sensitive the non-local Hanle fittings are, evidencing the complexity of obtaining spin transport information from such type of measurements

  10. Is prevention of acute pesticide poisoning effective and efficient, with Locally Adapted Personal Protective Equipment?

    DEFF Research Database (Denmark)

    Varma, Anshu; Neupane, Dinesh; Ellekilde Bonde, Jens Peter

    2016-01-01

    BACKGROUND: Farmers' risk of pesticide poisoning can be reduced with personal protective equipment but in low-income countries farmers' use of such equipment is limited. OBJECTIVE: To examine the effectiveness and efficiency of Locally Adapted Personal Protective Equipment to reduce organophosphate...... exposure among farmers. METHODS: In a crossover study, 45 male farmers from Chitwan, Nepal, were randomly allocated to work as usual applying organophosphate pesticides wearing Locally Adapted Personal Protective Equipment or Daily Practice Clothing. For seven days before each experiment, each farmer.......08;0.06]. Wearing the Locally Adapted Personal Protective Equipment versus Daily Practice Clothing gave the following results, respectively: comfort 75.6% versus 100%, sense of heat 64.4% versus 31.3%, other problems 44.4% versus 33.3%, likeability 95.6% versus 77.8%. CONCLUSION: We cannot support the expectation...

  11. Destruction of Anderson localization by nonlinearity in kicked rotator at different effective dimensions

    International Nuclear Information System (INIS)

    Ermann, L; Shepelyansky, D L

    2014-01-01

    We study numerically the frequency modulated kicked nonlinear rotator with effective dimension d=1,2,3,4. We follow the time evolution of the model up to 10 9 kicks and determine the exponent α of subdiffusive spreading which changes from 0.35 to 0.5 when the dimension changes from d = 1 to 4. All results are obtained in a regime of relatively strong Anderson localization well below the Anderson transition point existing for d = 3, 4. We explain that this variation of the exponent is different from the usual d− dimensional Anderson models with local nonlinearity where α drops with increasing d. We also argue that the renormalization arguments proposed by Cherroret N et al (arXiv:1401.1038) are not valid for this model and the Anderson model with local nonlinearity in d = 3. (paper)

  12. LOCAL INSTITUTIONS’ MICRO CREDIT DELIVERY AND EFFECTS ON RURAL FARM HOUSEHOLDS’ POVERTY IN ABIA STATE, NIGERIA

    Directory of Open Access Journals (Sweden)

    Chidozie Onyedikachi ANYIRO

    2014-03-01

    Full Text Available The study examined the effect of local institutions’ micro credit delivery on rural farm household poverty status in Abia state, Nigeria. Multistage random sampling technique was employed in collecting data from two hundred and four (204 rural farm households in local institutions using structured interview schedule. The data were analyzed using descriptive statistics, poverty indices, and paired t-test. The study revealed reveals that the religious association granted the highest amount of credit (N91,950.0 to their members more than any other local institutions in the study area, while the mean amount demanded was N 128,491.3. The average annual contribution of members in different local association was N36357.35 with a low percentage cash contribution index of 10.59%. The result of the poverty indicators of the rural farm households in local institutions showed that the poverty line (mean monthly household expenditure of the farm households was N16 N20648.94 per month or N 247787.28 per annum. The incidence of poverty otherwise called the head count ratio was 0.4863 while the coefficient of poverty gap (poverty depth was 0.2458. The result of the paired t-test showed that the local institutions’ micro credits impacted significantly on the mean annual farm income and monthly expenditures of the rural farm households in the study area. It was however, recommended that the autonomous local institutions should be integrated into the current poverty alleviation programme of the government and making them channels for loan delivery with a view to strengthening the financial capacity of its members as well as achieving the Millennium development goals of reducing poverty by half.

  13. Efekty komunikacyjne sponsoringu na lokalnych rynkach sportowych = The communication effects of sponsorship in local sports markets

    Directory of Open Access Journals (Sweden)

    Sławomir Kowalski

    2016-09-01

    Abstract                 Local sports market depends on the groups of stakeholders. One of them are the sponsors grouped around a particular club or sport.                 The problem that meet the organizers of sporting events or recreational activities is the inability to convince sponsors to the effectiveness of promotional activities based on the sport. Inability is due primarily to the fact that companies sponsoring do not use all aspects of the sponsorship and sometimes the club cannot indicate how it should be used. Meanwhile, the lasting effects of sponsorship can bring benefits not only its image but also financial, informational, promotional.                 The primary purpose of the article is to study the effect of the use of the communication by the sponsors local sports clubs. This study will be done by evaluating how the sponsors of these clubs to communicate the fact to support the outside. Space research will be websites of sports clubs from Częstochowa region and information from websites of their sponsors. Article will consist of theoretical and practical parts. In the theoretical part will be presented briefly the most important and latest information on modern forms of communication with the use in companies. The practical part of the study will fill your own.                 During the study it will be verified thesis that sponsors local sports clubs faint attach importance to communicate that fact to potential customers. In this way also it verifies opinion on the effectiveness of sponsorship and lack of ability to use image-supporting local sports clubs. The article is part of a multi-lane testing on the functioning of local sports clubs.

  14. Switching between global and local levels: the level repetition effect and its hemispheric asymmetry

    Science.gov (United States)

    Kéïta, Luc; Bedoin, Nathalie; Burack, Jacob A.; Lepore, Franco

    2014-01-01

    The global level of hierarchical stimuli (Navon’s stimuli) is typically processed quicker and better than the local level; further differential hemispheric dominance is described for local (left hemisphere, LH) and global (right hemisphere, RH) processing. However, neuroimaging and behavioral data indicate that stimulus category (letter or object) could modulate the hemispheric asymmetry for the local level processing. Besides, when the targets are unpredictably displayed at the global or local level, the participant has to switch between levels, and the magnitude of the switch cost increases with the number of repeated-level trials preceding the switch. The hemispheric asymmetries associated with level switching is an unresolved issue. LH areas may be involved in carrying over the target level information in case of level repetition. These areas may also largely participate in the processing of level-changed trials. Here we hypothesized that RH areas underly the inhibitory mechanism performed on the irrelevant level, as one of the components of the level switching process. In an experiment using a within-subject design, hierarchical stimuli were briefly presented either to the right or to the left visual field. 32 adults were instructed to identify the target at the global or local level. We assessed a possible RH dominance for the non-target level inhibition by varying the attentional demands through the manipulation of level repetitions (two or gour repeated-level trials before the switch). The behavioral data confirmed a LH specialization only for the local level processing of letter-based stimuli, and detrimental effect of increased level repetitions before a switch. Further, data provides evidence for a RH advantage in inhibiting the non-target level. Taken together, the data supports the notion of the existence of multiple mechanisms underlying level-switch effects. PMID:24723903

  15. Calculation methods' comparative analysis of monorail hoist crane local bending effects

    Directory of Open Access Journals (Sweden)

    Cvijović Goran M.

    2016-01-01

    Full Text Available The results of numerical and experimental researches of local bending problems, carried on classic and medium-wide I profiles, were a basis for the adoption of the current standards (EN 15011: 2014 which regulates the action of the local stress caused by the effect of cart wheels. Regarding the fact that IPB (HE-B wide flange profiles are largely used for production of the main carriers of monorail transport systems, this paper presents the results of the action of the local stress caused by the effect of cart wheels on the HE-A flange profile, using the methods and procedures of relevant researchers, the procedures prescribed by the standard EN 15011 as well as the results of calculations using finite element method. It has been revealed, based on comparative analysis of the results, that in the transition zone low flange / rib longitudinal local stress on the lower contour flange, determined using the above mentioned standards have tightening characteristic, while all other methods, including finite element method, give the pressing nature of the considered voltage. In addition, all of these procedures, except for the finite element method, adopt the assumption that absolute value of voltage, caused by local bending on upper and lower contour of the loaded flange, are the same, and there is no physical justification. Bearing in mind the fact that stress identification, caused by the flange local bending, is an extremely important phase proving the strength of monorail beams, we may conclude that the application of standard EN 15011 does not provide reliable results when it comes to wide flange profiles.

  16. Probing student reasoning approaches through the lens of dual-process theories: A case study in buoyancy

    Science.gov (United States)

    Gette, Cody R.; Kryjevskaia, Mila; Stetzer, MacKenzie R.; Heron, Paula R. L.

    2018-06-01

    A growing body of scholarly work indicates that student performance on physics problems stems from many factors, including relevant conceptual understanding. However, in contexts in which significant conceptual difficulties have been documented via research, it can be difficult to pinpoint and isolate such factors because students' written and interview responses rarely reveal the full richness of their conscious and, perhaps more importantly, subconscious reasoning paths. In this investigation, informed by dual-process theories of reasoning and decision making as well as the theoretical construct of accessibility, we conducted a series of experiments in order to gain greater insight into the factors impacting student performance on the "five-block problem," which has been used in the literature to probe student thinking about buoyancy. In particular, we examined both the impact of problem design (including salient features and cueing) and the impact of targeted instruction focused on density-based arguments for sinking and floating and on neutral buoyancy. The investigation found that instructional modifications designed to remove the strong intuitive appeal of the first-available response led to significantly improved performance, without improving student conceptual understanding of the requisite buoyancy concepts. As such, our findings represent an important first step in identifying systematic strategies for using theories from cognitive science to guide the development and refinement of research-based instructional materials.

  17. Probing student reasoning approaches through the lens of dual-process theories: A case study in buoyancy

    Directory of Open Access Journals (Sweden)

    Cody R. Gette

    2018-03-01

    Full Text Available A growing body of scholarly work indicates that student performance on physics problems stems from many factors, including relevant conceptual understanding. However, in contexts in which significant conceptual difficulties have been documented via research, it can be difficult to pinpoint and isolate such factors because students’ written and interview responses rarely reveal the full richness of their conscious and, perhaps more importantly, subconscious reasoning paths. In this investigation, informed by dual-process theories of reasoning and decision making as well as the theoretical construct of accessibility, we conducted a series of experiments in order to gain greater insight into the factors impacting student performance on the “five-block problem,” which has been used in the literature to probe student thinking about buoyancy. In particular, we examined both the impact of problem design (including salient features and cueing and the impact of targeted instruction focused on density-based arguments for sinking and floating and on neutral buoyancy. The investigation found that instructional modifications designed to remove the strong intuitive appeal of the first-available response led to significantly improved performance, without improving student conceptual understanding of the requisite buoyancy concepts. As such, our findings represent an important first step in identifying systematic strategies for using theories from cognitive science to guide the development and refinement of research-based instructional materials.

  18. Local Peltier-effect-induced reversible metal–insulator transition in VO2 nanowires

    International Nuclear Information System (INIS)

    Takami, Hidefumi; Kanki, Teruo; Tanaka, Hidekazu

    2016-01-01

    We report anomalous resistance leaps and drops in VO 2 nanowires with operating current density and direction, showing reversible and nonvolatile switching. This event is associated with the metal–insulator phase transition (MIT) of local nanodomains with coexistence states of metallic and insulating phases induced by thermoelectric cooling and heating effects. Because the interface of metal and insulator domains has much different Peltier coefficient, it is possible that a significant Peltier effect would be a source of the local MIT. This operation can be realized by one-dimensional domain configuration in VO 2 nanowires because one straight current path through the electronic domain-interface enables theoretical control of thermoelectric effects. This result will open a new method of reversible control of electronic states in correlated electron materials.

  19. Local Peltier-effect-induced reversible metal–insulator transition in VO{sub 2} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Hidefumi; Kanki, Teruo, E-mail: kanki@sanken.osaka-u.ac.jp, E-mail: h-tanaka@sanken.osaka-u.ac.jp; Tanaka, Hidekazu, E-mail: kanki@sanken.osaka-u.ac.jp, E-mail: h-tanaka@sanken.osaka-u.ac.jp [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2016-06-15

    We report anomalous resistance leaps and drops in VO{sub 2} nanowires with operating current density and direction, showing reversible and nonvolatile switching. This event is associated with the metal–insulator phase transition (MIT) of local nanodomains with coexistence states of metallic and insulating phases induced by thermoelectric cooling and heating effects. Because the interface of metal and insulator domains has much different Peltier coefficient, it is possible that a significant Peltier effect would be a source of the local MIT. This operation can be realized by one-dimensional domain configuration in VO{sub 2} nanowires because one straight current path through the electronic domain-interface enables theoretical control of thermoelectric effects. This result will open a new method of reversible control of electronic states in correlated electron materials.

  20. Localized Effects in the Nonlinear Behavior of Sandwich Panels with a Transversely Flexible Core

    DEFF Research Database (Denmark)

    Frostig, Y.; Thomsen, Ole Thybo

    2005-01-01

    This paper presents the results of an investigation of the role of localized effects within the geometrically nonlinear domain on structural sandwich panels with a "compliant" core. Special emphasis is focused on the nonlinear response near concentrated loads and stiffened core regions. The adopted...... nonlinear analysis approach incorporates the effects of the vertical flexibility of the core, and it is based on the approach of the High-order Sandwich Panel Theory (HSAPT). The results demonstrate that the effects of localized loads, when taken into the geometrically nonlinear domain, change the response...... of the panel from a strength problem controlled by stress constraints into a stability problem with unstable limit point behavior when force-controlled loads are applied. The stability problem emerge as the nonlinear response develops with the formation of a small number of buckling waves in the compressed...

  1. The effect of brain lesions on sound localization in complex acoustic environments.

    Science.gov (United States)

    Zündorf, Ida C; Karnath, Hans-Otto; Lewald, Jörg

    2014-05-01

    Localizing sound sources of interest in cluttered acoustic environments--as in the 'cocktail-party' situation--is one of the most demanding challenges to the human auditory system in everyday life. In this study, stroke patients' ability to localize acoustic targets in a single-source and in a multi-source setup in the free sound field were directly compared. Subsequent voxel-based lesion-behaviour mapping analyses were computed to uncover the brain areas associated with a deficit in localization in the presence of multiple distracter sound sources rather than localization of individually presented sound sources. Analyses revealed a fundamental role of the right planum temporale in this task. The results from the left hemisphere were less straightforward, but suggested an involvement of inferior frontal and pre- and postcentral areas. These areas appear to be particularly involved in the spectrotemporal analyses crucial for effective segregation of multiple sound streams from various locations, beyond the currently known network for localization of isolated sound sources in otherwise silent surroundings.

  2. Localized persistent spin currents in defect-free quasiperiodic rings with Aharonov–Casher effect

    International Nuclear Information System (INIS)

    Qiu, R.Z.; Chen, C.H.; Cheng, Y.H.; Hsueh, W.J.

    2015-01-01

    We propose strongly localized persistent spin current in one-dimensional defect-free quasiperiodic Thue–Morse rings with Aharonov–Casher effect. The results show that the characteristics of these localized persistent currents depend not only on the radius filling factor, but also on the strength of the spin–orbit interaction. The maximum persistent spin currents in systems always appear in the ring near the middle position of the system array whether or not the Thue–Morse rings array is symmetrical. The magnitude of the persistent currents is proportional to the sharpness of the resonance peak, which is dependent on the bandwidth of the allowed band in the band structure. The maximum persistent spin currents also increase exponentially as the generation order of the system increases. - Highlights: • Strongly localized persistent spin current in quasiperiodic AC rings is proposed. • Localized persistent spin currents are much larger than those produced by traditional mesoscopic rings. • Characteristics of the localized persistent currents depend on the radius filling factor and SOI strength. • The maximum persistent current increases exponentially with the system order. • The magnitude of the persistent currents is related to the sharpness of the resonance

  3. Primary assembly of soil communities: disentangling the effect of dispersal and local environment.

    Science.gov (United States)

    Ingimarsdóttir, María; Caruso, Tancredi; Ripa, Jörgen; Magnúsdóttir, Olöf Birna; Migliorini, Massimo; Hedlund, Katarina

    2012-11-01

    It has long been recognised that dispersal abilities and environmental factors are important in shaping invertebrate communities, but their relative importance for primary soil community assembly has not yet been disentangled. By studying soil communities along chronosequences on four recently emerged nunataks (ice-free land in glacial areas) in Iceland, we replicated environmental conditions spatially at various geographical distances. This allowed us to determine the underlying factors of primary community assembly with the help of metacommunity theories that predict different levels of dispersal constraints and effects of the local environment. Comparing community assembly of the nunataks with that of non-isolated deglaciated areas indicated that isolation of a few kilometres did not affect the colonisation of the soil invertebrates. When accounting for effects of geographical distances, soil age and plant richness explained a significant part of the variance observed in the distribution of the oribatid mites and collembola communities, respectively. Furthermore, null model analyses revealed less co-occurrence than expected by chance and also convergence in the body size ratio of co-occurring oribatids, which is consistent with species sorting. Geographical distances influenced species composition, indicating that the community is also assembled by dispersal, e.g. mass effect. When all the results are linked together, they demonstrate that local environmental factors are important in structuring the soil community assembly, but are accompanied with effects of dispersal that may "override" the visible effect of the local environment.

  4. A Bayesian localized conditional autoregressive model for estimating the health effects of air pollution.

    Science.gov (United States)

    Lee, Duncan; Rushworth, Alastair; Sahu, Sujit K

    2014-06-01

    Estimation of the long-term health effects of air pollution is a challenging task, especially when modeling spatial small-area disease incidence data in an ecological study design. The challenge comes from the unobserved underlying spatial autocorrelation structure in these data, which is accounted for using random effects modeled by a globally smooth conditional autoregressive model. These smooth random effects confound the effects of air pollution, which are also globally smooth. To avoid this collinearity a Bayesian localized conditional autoregressive model is developed for the random effects. This localized model is flexible spatially, in the sense that it is not only able to model areas of spatial smoothness, but also it is able to capture step changes in the random effects surface. This methodological development allows us to improve the estimation performance of the covariate effects, compared to using traditional conditional auto-regressive models. These results are established using a simulation study, and are then illustrated with our motivating study on air pollution and respiratory ill health in Greater Glasgow, Scotland in 2011. The model shows substantial health effects of particulate matter air pollution and nitrogen dioxide, whose effects have been consistently attenuated by the currently available globally smooth models. © 2014, The Authors Biometrics published by Wiley Periodicals, Inc. on behalf of International Biometric Society.

  5. Effect of superconducting correlation on the localization of quasiparticles in low dimensions

    International Nuclear Information System (INIS)

    Xiang, T.

    1995-01-01

    Localization lengths of superconducting quasiparticles λ s are evaluated and compared with the corresponding normal-state values λ n in one-dimensional (1D) and two-dimensional lattices. The effect of superconducting correlation on the localization of quasiparticles is generally stronger in an off-site pairing state than in an on-site pairing state. The modification of superconducting correlation to λ is strongly correlated with the density of states (DOS) of superconducting quasiparticles. λ s drops within the energy gap but is largely enhanced around energies where DOS peaks appear. For a gapless pairing state in 1D or a d-wave pairing state in 2D, λ s /λ n at the Fermi energy E F is of order 1 and determined purely by the value of gap parameter not by the random potential. For the d-wave pairing state, the localization effect is largely weakened compared with the corresponding normal state and quasiparticles with energies close to E F are more strongly localized than other low-energy quasiparticles

  6. Effect of local cultural context on the success of community-based conservation interventions.

    Science.gov (United States)

    Waylen, Kerry A; Fischer, Anke; McGowan, Philip J K; Thirgood, Simon J; Milner-Gulland, E J

    2010-08-01

    Conservation interventions require evaluation to understand what factors predict success or failure. To date, there has been little systematic investigation of the effect of social and cultural context on conservation success, although a large body of literature argues it is important. We investigated whether local cultural context, particularly local institutions and the efforts of interventions to engage with this culture significantly influence conservation outcomes. We also tested the effects of community participation, conservation education, benefit provision, and market integration. We systematically reviewed the literature on community-based conservation and identified 68 interventions suitable for inclusion. We used a protocol to extract and code information and evaluated a range of measures of outcome success (attitudinal, behavioral, ecological, and economic). We also examined the association of each predictor with each outcome measure and the structure of predictor covariance. Local institutional context influenced intervention outcomes, and interventions that engaged with local institutions were more likely to succeed. Nevertheless, there was limited support for the role of community participation, conservation education, benefit provision, and market integration on intervention success. We recommend that conservation interventions seek to understand the societies they work with and tailor their activities accordingly. Systematic reviews are a valuable approach for assessing conservation evidence, although sensitive to the continuing lack of high-quality reporting on conservation interventions.

  7. Construction of exact constants of motion and effective models for many-body localized systems

    Science.gov (United States)

    Goihl, M.; Gluza, M.; Krumnow, C.; Eisert, J.

    2018-04-01

    One of the defining features of many-body localization is the presence of many quasilocal conserved quantities. These constants of motion constitute a cornerstone to an intuitive understanding of much of the phenomenology of many-body localized systems arising from effective Hamiltonians. They may be seen as local magnetization operators smeared out by a quasilocal unitary. However, accurately identifying such constants of motion remains a challenging problem. Current numerical constructions often capture the conserved operators only approximately, thus restricting a conclusive understanding of many-body localization. In this work, we use methods from the theory of quantum many-body systems out of equilibrium to establish an alternative approach for finding a complete set of exact constants of motion which are in addition guaranteed to represent Pauli-z operators. By this we are able to construct and investigate the proposed effective Hamiltonian using exact diagonalization. Hence, our work provides an important tool expected to further boost inquiries into the breakdown of transport due to quenched disorder.

  8. Effect of speed on local dynamic stability of locomotion under different task constraints in running.

    Science.gov (United States)

    Mehdizadeh, Sina; Arshi, Ahmed Reza; Davids, Keith

    2014-01-01

    A number of studies have investigated effects of speed on local dynamic stability of walking, although this relationship has been rarely investigated under changing task constraints, such as during forward and backward running. To rectify this gap in the literature, the aim of this study was to investigate the effect of running speed on local dynamic stability of forward and backward running on a treadmill. Fifteen healthy male participants took part in this study. Participants ran in forward and backward directions at speeds of 80%, 100% and 120% of their preferred running speed. The three-dimensional motion of a C7 marker was recorded using a motion capture system. Local dynamic stability of the marker was quantified using short- and long-term largest finite-time Lyapunov exponents (LyE). Results showed that short-term largest finite-time LyE values increased with participant speed meaning that local dynamic stability decreased with increasing speed. Long-term largest finite-time LyEs, however, remained unaffected as speed increased. Results of this study indicated that, as in walking, slow running is more stable than fast running. These findings improve understanding of how stability is regulated when constraints on the speed of movements is altered. Implications for the design of rehabilitation or sport practice programmes suggest how task constraints could be manipulated to facilitate adaptations in locomotion stability during athletic training.

  9. Local impact effects on concrete target due to missile: An empirical and numerical approach

    International Nuclear Information System (INIS)

    Ranjan, Rajiv; Banerjee, Sauvik; Singh, R.K.; Banerji, Pradipta

    2014-01-01

    Highlights: • Local impact effect of hard missile on reinforced concrete targets has been studied. • Review of empirical formulation for predicting local response carried out. • Numerical simulation of experimental test of Kojima (1991) carried out. • Divergence of FE results with those obtained using emperical formulations. • Close match of numerical simulation results with experimental data. - Abstract: Concrete containment walls and internal concrete barrier walls of a Nuclear Power Plant safety related structures are often required to be designed for externally and internally generated missiles. Potential missiles include external extreme wind generated missiles, aircraft crash and internal accident generated missiles such as impact due to turbine blade failure and steel pipe missiles resulting from pipe break. The objective of the present paper is to compare local missile impact effects on reinforced concrete target using available empirical formulations with those obtained using LS-DYNA numerical simulation. The use of numerical simulations for capturing the transient structural response has become increasingly used for structural design against impact loads. They overcome the limits of applicability of the empirical formulae and also provide information on stress and deformation fields, which may be used to improve the resistance of the concrete. Finite element (FE) analyses of an experimental impact problem reported by Kojima (1991) are carried out that are able to capture the missile impact effects; in terms of local and global damage. The continuous surface cap model has been used for modelling concrete behaviour. A range of missile velocity has been considered to simulate local missile impact phenomenon and modes of failure and to capture the concrete response from elastic to plastic fracture. A comparison is then made between the empirical formulations, numerical simulation results, and available experimental results of slab impact tests

  10. Effect of local anaesthesia and/or analgesia on pain responses induced by piglet castration

    Directory of Open Access Journals (Sweden)

    Nyman Görel

    2011-05-01

    Full Text Available Abstract Background Surgical castration in male piglets is painful and methods that reduce this pain are requested. This study evaluated the effect of local anaesthesia and analgesia on vocal, physiological and behavioural responses during and after castration. A second purpose was to evaluate if herdsmen can effectively administer anaesthesia. Methods Four male piglets in each of 141 litters in five herds were randomly assigned to one of four treatments: castration without local anaesthesia or analgesia (C, controls, analgesia (M, meloxicam, local anaesthesia (L, lidocaine, or both local anaesthesia and analgesia (LM. Lidocaine (L, LM was injected at least three minutes before castration and meloxicam (M, LM was injected after castration. During castration, vocalisation was measured and resistance movements judged. Behaviour observations were carried out on the castration day and the following day. The day after castration, castration wounds were ranked, ear and skin temperature was measured, and blood samples were collected for analysis of acute phase protein Serum Amyloid A concentration (SAA. Piglets were weighed on the castration day and at three weeks of age. Sickness treatments and mortality were recorded until three weeks of age. Results Piglets castrated with lidocaine produced calls with lower intensity (p p p = 0.06, n.s. and the following day (p = 0.02. Controls had less swollen wounds compared to piglets assigned to treatments M, L and LM (p p = 0.005; p = 0.05 for C + L compared to M + LM. Ear temperature was higher (p Conclusions The study concludes that lidocaine reduced pain during castration and that meloxicam reduced pain after castration. The study also concludes that the herdsmen were able to administer local anaesthesia effectively.

  11. Effect of high-volume systematic local infiltration analgesia in Caesarean section

    DEFF Research Database (Denmark)

    Larsen, Klaus Richter; Kristensen, B B; Rasmussen, M A

    2015-01-01

    BACKGROUND: Pain after Caesarean section is often treated with opioids with a risk of side effects. Wound infiltration with local anaesthetics is effective and has few side effects, but volume vs. dose concentration has not been examined. METHODS: Ninety patients scheduled for elective Caesarean...... found concerning time spent in the PACU, to first mobilisation or in number of women with nausea/vomiting (P ≥ 0.05). No complications related to ropivacaine were observed. CONCLUSIONS: Systematic infiltration with a high concentration, low volume compared with low concentration, high volume showed...

  12. Nonlinear Local Deformations of Red Blood Cell Membranes: Effects of Toxins and Pharmaceuticals (Part 2

    Directory of Open Access Journals (Sweden)

    Alexander M. Chernysh

    2018-01-01

    Full Text Available Modifiers of membranes cause local defects on the cell surface. Measurement of the rigidity at the sites of local defects can provide further information about the structure of defects and mechanical properties of altered membranes.The purpose of the study: a step-by-step study of the process of a nonlinear deformation of red blood cells membranes under the effect of modifiers of different physico-chemical nature.Materials and methods. The membrane deformation of a viscoelastic composite erythrocyte construction inside a cell was studied by the atomic force spectroscopy. Nonlinear deformations formed under the effect of hemin, Zn2+ ions, and verapamil were studied.Results. The process of elastic deformation of the membrane with the indentation of a probe at the sites of local defects caused by modifiers was demonstrated. The probe was inserted during the same step of the piezo scanner z displacement; the probe indentation occured at the different discrete values of h, which are the functions of the membrane structure. At the sites of domains, under the effect of the hemin, tension areas and plasticity areas appeared. A mathematical model of probe indentation at the site of membrane defects is presented.Conclusion. The molecular mechanisms of various types of nonlinear deformations occurring under the effect of toxins are discussed. The results of the study may be of interest both for fundamental researchers of the blood cell properties and for practical reanimatology and rehabilitology. 

  13. Preliminary experimentally-validated forced and mixed convection computational simulations of the Rotatable Buoyancy Tunnel

    International Nuclear Information System (INIS)

    Clifford, Corey E.; Kimber, Mark L.

    2015-01-01

    Although computational fluid dynamics (CFD) has not been directly utilized to perform safety analyses of nuclear reactors in the United States, several vendors are considering adopting commercial numerical packages for current and future projects. To ensure the accuracy of these computational models, it is imperative to validate the assumptions and approximations built into commercial CFD codes against physical data from flows analogous to those in modern nuclear reactors. To this end, researchers at Utah State University (USU) have constructed the Rotatable Buoyancy Tunnel (RoBuT) test facility, which is designed to provide flow and thermal validation data for CFD simulations of forced and mixed convection scenarios. In order to evaluate the ability of current CFD codes to capture the complex physics associated with these types of flows, a computational model of the RoBuT test facility is created using the ANSYS Fluent commercial CFD code. The numerical RoBuT model is analyzed at identical conditions to several experimental trials undertaken at USU. Each experiment is reconstructed numerically and evaluated with the second-order Reynolds stress model (RSM). Two different thermal boundary conditions at the heated surface of the RoBuT test section are investigated: constant temperature (isothermal) and constant surface heat flux (isoflux). Additionally, the fluid velocity at the inlet of the test section is varied in an effort to modify the relative importance of natural convection heat transfer from the heated wall of the RoBuT. Mean velocity, both in the streamwise and transverse directions, as well as components of the Reynolds stress tensor at three points downstream of the RoBuT test section inlet are compared to results obtained from experimental trials. Early computational results obtained from this research initiative are in good agreement with experimental data obtained from the RoBuT facility and both the experimental data and numerical method can be used

  14. Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Nikolaos Kokkos

    2016-04-01

    Full Text Available A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively. Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island, depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1, tending to destroy surface meso-scale eddies.

  15. Anisotropy of the monomer random walk in a polymer melt: local-order and connectivity effects

    International Nuclear Information System (INIS)

    Bernini, S; Leporini, D

    2016-01-01

    The random walk of a bonded monomer in a polymer melt is anisotropic due to local order and bond connectivity. We investigate both effects by molecular-dynamics simulations on melts of fully-flexible linear chains ranging from dimers (M  =  2) up to entangled polymers (M  =  200). The corresponding atomic liquid is also considered a reference system. To disentangle the influence of the local geometry and the bond arrangements, and to reveal their interplay, we define suitable measures of the anisotropy emphasising either the former or the latter aspect. Connectivity anisotropy, as measured by the correlation between the initial bond orientation and the direction of the subsequent monomer displacement, shows a slight enhancement due to the local order at times shorter than the structural relaxation time. At intermediate times—when the monomer displacement is comparable to the bond length—a pronounced peak and then decays slowly as t −1/2 , becoming negligible when the displacement is as large as about five bond lengths, i.e. about four monomer diameters or three Kuhn lengths. Local-geometry anisotropy, as measured by the correlation between the initial orientation of a characteristic axis of the Voronoi cell and the subsequent monomer dynamics, is affected at shorter times than the structural relaxation time by the cage shape with antagonistic disturbance by the connectivity. Differently, at longer times, the connectivity favours the persistence of the local-geometry anisotropy, which vanishes when the monomer displacement exceeds the bond length. Our results strongly suggest that the sole consideration of the local order is not enough to understand the microscopic origin of the rattling amplitude of the trapped monomer in the cage of the neighbours. (paper)

  16. Using local multiplicity to improve effect estimation from a hypothesis-generating pharmacogenetics study.

    Science.gov (United States)

    Zou, W; Ouyang, H

    2016-02-01

    We propose a multiple estimation adjustment (MEA) method to correct effect overestimation due to selection bias from a hypothesis-generating study (HGS) in pharmacogenetics. MEA uses a hierarchical Bayesian approach to model individual effect estimates from maximal likelihood estimation (MLE) in a region jointly and shrinks them toward the regional effect. Unlike many methods that model a fixed selection scheme, MEA capitalizes on local multiplicity independent of selection. We compared mean square errors (MSEs) in simulated HGSs from naive MLE, MEA and a conditional likelihood adjustment (CLA) method that model threshold selection bias. We observed that MEA effectively reduced MSE from MLE on null effects with or without selection, and had a clear advantage over CLA on extreme MLE estimates from null effects under lenient threshold selection in small samples, which are common among 'top' associations from a pharmacogenetics HGS.

  17. Effect of water on the local electric potential of simulated ionic micelles

    Energy Technology Data Exchange (ETDEWEB)

    Brodskaya, Elena N.; Vanin, Alexander A., E-mail: alexvanin@yandex.ru [Institute of Chemistry, St. Petersburg State University, Universitetskiy pr. 26, Petrodvoretz, St. Petersburg 198504 (Russian Federation)

    2015-07-28

    Ionic micelles in an aqueous solution containing single-charged counter-ions have been simulated by molecular dynamics. For both cationic and anionic micelles, it has been demonstrated that explicit description of solvent has strong effect on the micelle’s electric field. The sign of the local charge alters in the immediate vicinity of the micellar crown and the electric potential varies nonmonotonically. Two micelle models have been examined: the hybrid model with a rigid hydrocarbon core and the atomistic model. For three molecular models of water (Simple Point Charge model (SPC), Transferable Intermolecular Potential 5- Points (TIP5P) and two-centered S2), the results have been compared with those for the continuum solvent model. The orientational ordering of solvent molecules has strong effect on the local electric field surprisingly far from the micelle surface.

  18. Size effects and strain localization in atomic-scale cleavage modeling

    International Nuclear Information System (INIS)

    Elsner, B A M; Müller, S

    2015-01-01

    In this work, we study the adhesion and decohesion of Cu(1 0 0) surfaces using density functional theory (DFT) calculations. An upper stress to surface decohesion is obtained via the universal binding energy relation (UBER), but the model is limited to rigid separation of bulk-terminated surfaces. When structural relaxations are included, an unphysical size effect arises if decohesion is considered to occur as soon as the strain energy equals the energy of the newly formed surfaces. We employ the nudged elastic band (NEB) method to show that this size effect is opposed by a size-dependency of the energy barriers involved in the transition. Further, we find that the transition occurs via a localization of bond strain in the vicinity of the cleavage plane, which resembles the strain localization at the tip of a sharp crack that is predicted by linear elastic fracture mechanics. (paper)

  19. Preferred Air Velocity and Local Cooling Effect of desk fans in warm environments

    DEFF Research Database (Denmark)

    Simone, Angela; Olesen, Bjarne W.

    2013-01-01

    to compensate for higher environmental temperatures at the expense of no or relatively low energy consumption. When using desk fans, local air movement is generated around the occupant and a certain cooling effect is perceived. The impact of the local air movement generated by different air flow patterns......Common experiences, standards, and laboratory studies show that increased air velocity helps to offset warm sensation due to high environmental temperatures. In warm climate regions the opening of windows and the use of desk or ceiling fans are the most common systems to generate increased airflows......, and the possibility to keep comfortable conditions for the occupants in warm environments were evaluated in studies with human subjects. In an office-like climatic chamber, the effect of higher air velocity was investigated at room temperatures between 26°C to 34°C and at constant absolute humidity of 12.2 g...

  20. CMB anomalies and the effects of local features of the inflaton potential

    Energy Technology Data Exchange (ETDEWEB)

    Cadavid, Alexander Gallego [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); ICRANet, Pescara (Italy); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Romano, Antonio Enea [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); University of Torino, Department of Physics, Turin (Italy); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Gariazzo, Stefano [University of Torino, Department of Physics, Turin (Italy); INFN, Sezione di Torino, Turin (Italy); Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Paterna, Valencia (Spain)

    2017-04-15

    Recent analysis of the WMAP and Planck data have shown the presence of a dip and a bump in the spectrum of primordial perturbations at the scales k = 0.002 Mpc{sup -1}, respectively. We analyze for the first time the effects of a local feature in the inflaton potential to explain the observed deviations from scale invariance in the primordial spectrum. We perform a best-fit analysis of the cosmic microwave background (CMB) radiation temperature and polarization data. The effects of the features can improve the agreement with observational data respect to the featureless model. The best-fit local feature affects the primordial curvature spectrum mainly in the region of the bump, leaving the spectrum unaffected on other scales. (orig.)

  1. Effects of local cardiac denervation on cardiac innervation and ventricular arrhythmia after chronic myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Xudong Liu

    Full Text Available Modulation of the autonomic nervous system (ANS has already been demonstrated to display antiarrhythmic effects in patients and animals with MI. In this study, we investigated whether local cardiac denervation has any beneficial effects on ventricular electrical stability and cardiac function in the chronic phase of MI.Twenty-one anesthetized dogs were randomly assigned into the sham-operated, MI and MI-ablation groups, respectively. Four weeks after local cardiac denervation, LSG stimulation was used to induce VPCs and VAs. The ventricular fibrillation threshold (VFT and the incidence of inducible VPCs were measured with electrophysiological protocol. Cardiac innervation was determined with immunohistochemical staining of growth associated protein-43 (GAP43 and tyrosine hydroxylase (TH. The global cardiac and regional ventricular function was evaluated with doppler echocardiography in this study.Four weeks after operation, the incidence of inducible VPC and VF in MI-ablation group were significantly reduced compared to the MI dogs (p<0.05. Moreover, local cardiac denervation significantly improved VFT in the infarcted border zone (p<0.05. The densities of GAP43 and TH-positive nerve fibers in the infarcted border zone in the MI-ablation group were lower than those in the MI group (p<0.05. However, the local cardiac denervation did not significantly improve cardiac function in the chronic phase of MI, determined by the left ventricle diameter (LV, left atrial diameter (LA, ejection fraction (EF.Summarily, in the chronic phase of MI, local cardiac denervation reduces the ventricular electrical instability, and attenuates spatial heterogeneity of sympathetic nerve reconstruction. Our study suggests that this methodology might decrease malignant ventricular arrhythmia in chronic MI, and has a great potential for clinical application.

  2. Cash Management, Revenue Sources and Cost Effective Methods of Revenue Collection at Local Government Level

    OpenAIRE

    Mustapha Gimba Kumshe; Kagu Bukar

    2013-01-01

    The main objective of this paper was to focus on the elements, objectives, goals and importance of cash management; and also to examine the sources of revenue and cost effective collections for local governments. The elements of cash management are identified as establishing bank relations, preparing cash flow statements, estimating collection receipts and analyzing cash flow and preparing a budget. Amongst the objectives of cash management is to ensure availability of cash resources at all t...

  3. 2012 National Park visitor spending effects: economic contributions to local communities, states, and the nation

    Science.gov (United States)

    Cullinane Thomas, Catherine; Huber, Christopher C.; Koontz, Lynne

    2014-01-01

    The National Park Service (NPS) manages the nation's most iconic destinations that attract millions of visitors from across the nation and around the world. Trip-related spending by NPS visitors generates and supports a considerable amount of economic activity within park gateway communities. This economic effects analysis measures how NPS visitor spending cycles through local economies, generating business sales and supporting jobs and income.

  4. Is Kinesio Taping to Generate Skin Convolutions Effective for Increasing Local Blood Circulation?

    OpenAIRE

    Yang, Jae-Man; Lee, Jung-Hoon

    2018-01-01

    Background It is unclear whether traditional application of Kinesio taping, which produces wrinkles in the skin, is effective for improving blood circulation. This study investigated local skin temperature changes after the application of an elastic therapeutic tape using convolution and non-convolution taping methods (CTM/NCTM). Material/Methods Twenty-eight pain-free men underwent CTM and NCTM randomly applied to the right and left sides of the lower back. Using infrared thermography, skin ...

  5. A local effect model-based interpolation framework for experimental nanoparticle radiosensitisation data

    OpenAIRE

    Brown, Jeremy M. C.; Currell, Fred J.

    2017-01-01

    A local effect model (LEM)-based framework capable of interpolating nanoparticle-enhanced photon-irradiated clonogenic cell survival fraction measurements as a function of nanoparticle concentration was developed and experimentally benchmarked for gold nanoparticle (AuNP)-doped bovine aortic endothelial cells (BAECs) under superficial kilovoltage X-ray irradiation. For three different superficial kilovoltage X-ray spectra, the BAEC survival fraction response was predicted for two different Au...

  6. The effect of radionuclides and their carriers on diffusion coefficient of radionuclides in local rocks

    International Nuclear Information System (INIS)

    Othman, I.; Takriti, S.

    1995-07-01

    The diffusion coefficient of sup 9 sup 0 Sr and sup 1 sup 3 sup 7 Cs has been calculated for different local rocks in stationary and dynamic state. The effect of pH radioisotope solution dependence in shown by diffusion coefficient in some rocks. The results show that the cement and dolomite have the best quality of radioisotope retention which do not allow them to pollute the environment. (author). 6 refs., 2 tabs., 13 figs

  7. Nested separatrices in simple shear flows: the effect of localized disturbances on stagnation lines

    OpenAIRE

    Wilson, M.C.T.; Gaskell, P.H.; Savage, M.D.

    2005-01-01

    The effects of localized two-dimensional disturbances on the structure of shear flows featuring a stagnation line are investigated. A simple superposition of a planar Couette flow and Moffatt's [J. Fluid Mech. 18, 1--18 (1964)] streamfunction for the decay of a disturbance between infinite stationary parallel plates shows that in general the stagnation line is replaced by a chain of alternating elliptic and hyperbolic stagnation points with a separation equal to 2.78 times the half-gap betwee...

  8. Some Non Genetic Factors Effects on Morphostructural Growth of Local Kids in Tunisian Arid Area

    OpenAIRE

    Ben Ammar Elgaaied Amel; Khorchani Touhami; Ben Amor Mohamed; Gaddour Amor; Najari Sghaier; Ouni Mabrouk

    2008-01-01

    Data corresponding of 276 local kids` periodic control, harvested during 4 years (2001-2005) under pastoral mode in Tunisian arid region, was used to study some factors effects upon body parts evolution after birth. Morphostructural variables were; body length, height-at-withers and heart girth. The linear measurement periodically registered at every control day from birth and till 5 months age. For each kid, performances were standardized at typical ages; birth, 30, 60, 90, 120 and 150...

  9. Investigation of localization effect in GaN-rich InGaN alloys and ...

    Indian Academy of Sciences (India)

    Abstract. The temperature-dependent PL properties of GaN-rich InxGa1−xN alloys is investigated and S-shaped temperature dependence is observed in all InGaN samples. It is found that the origin of localization effect in samples. A and B are different from that in sample C. For samples A and B, In content fluctuations ...

  10. A new cross-effect in local relativistic thermodynamics of irreversible processes

    International Nuclear Information System (INIS)

    Gariel, J.

    1981-01-01

    It is shown that the supplementary term qsup(α)usub(α) which appears in the caloric conducting fluid Eckart's theory (where qsup(α) is the derivative by the curvilinear absciss of the calorific conduction density and usub(α) the local unitary speed) states a thermodynamics construction problem. We can solve this one by admitting the existence of a new relativistic 'thermokinetic' cross-effect, which leads to the relativistic Fourier's hypothesis of Pham Mau Quan [fr

  11. Effect of configuration widths on the spectra of local thermodynamic equilibrium plasmas

    International Nuclear Information System (INIS)

    Bar-Shalom, A.; Oreg, J.; Goldstein, W.H.

    1995-01-01

    We present the extension of the supertransition-array (STA) theory to include configuration widths in the spectra of local thermodynamic equilibrium (LTE) plasmas. Exact analytic expressions for the moments of a STA are given, accounting for the detailed contributions of individual levels within the configurations that belong to a STA. The STA average energy is shifted and an additional term appears in its variance. Various cases are presented, demonstrating the effect of these corrections on the LTE spectrum

  12. [Comparative effects of vitamin C on the effects of local anesthetics ropivacaine, bupivacaine, and lidocaine on human chondrocytes].

    Science.gov (United States)

    Tian, Jun; Li, Yan

    2016-01-01

    Intra-articular injections of local anesthetics are commonly used to enhance post-operative analgesia following orthopedic surgery as arthroscopic surgeries. Nevertheless, recent reports of severe complications due to the use of intra-articular local anesthetic have raised concerns. The study aims to assess use of vitamin C in reducing adverse effects of the most commonly employed anesthetics - ropivacaine, bupivacaine and lidocaine - on human chondrocytes. The chondrocyte viability following exposure to 0.5% bupivacaine or 0.75% ropivacaine or 1.0% lidocaine and/or vitamin C at doses 125, 250 and 500μM was determined by Live/Dead assay and annexin V staining. Expression levels of caspases 3 and 9 were assessed using antibodies by Western blotting. Flow cytometry was performed to analyze the generation of reactive oxygen species. On exposure to the local anesthetics, chondrotoxicity was found in the order ropivacaineC effectively improved the reduced chondrocyte viability and decreased the raised apoptosis levels following exposure to anesthesia. At higher doses, vitamin C was found efficient in reducing the generation of reactive oxygen species and as well down-regulate the expressions of caspases 3 and 9. Vitamin C was observed to effectively protect chondrocytes against the toxic insult of local anesthetics ropivacaine, bupivacaine and lidocaine. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  13. Comparative effects of vitamin C on the effects of local anesthetics ropivacaine, bupivacaine, and lidocaine on human chondrocytes.

    Science.gov (United States)

    Tian, Jun; Li, Yan

    2016-01-01

    Intra-articular injections of local anesthetics are commonly used to enhance post-operative analgesia following orthopedic surgery as arthroscopic surgeries. Nevertheless, recent reports of severe complications due to the use of intra-articular local anesthetic have raised concerns. The study aims to assess use of vitamin C in reducing adverse effects of the most commonly employed anesthetics - ropivacaine, bupivacaine and lidocaine - on human chondrocytes. The chondrocyte viability following exposure to 0.5% bupivacaine or 0.75% ropivacaine or 1.0% lidocaine and/or vitamin C at doses 125, 250 and 500 μM was determined by LIVE/DEAD assay and annexin V staining. Expression levels of caspases 3 and 9 were assessed using antibodies by Western blotting. Flow cytometry was performed to analyze the generation of reactive oxygen species. On exposure to the local anesthetics, chondrotoxicity was found in the order ropivacaineC effectively improved the reduced chondrocyte viability and decreased the raised apoptosis levels following exposure to anesthesia. At higher doses, vitamin C was found efficient in reducing the generation of reactive oxygen species and as well down-regulate the expressions of caspases 3 and 9. Vitamin C was observed to effectively protect chondrocytes against the toxic insult of local anesthetics ropivacaine, bupivacaine and lidocaine. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  14. Global effects of local food-production crises: a virtual water perspective.

    Science.gov (United States)

    Tamea, Stefania; Laio, Francesco; Ridolfi, Luca

    2016-01-25

    By importing food and agricultural goods, countries cope with the heterogeneous global water distribution and often rely on water resources available abroad. The virtual displacement of the water used to produce such goods (known as virtual water) connects together, in a global water system, all countries participating to the international trade network. Local food-production crises, having social, economic or environmental origin, propagate in this network, modifying the virtual water trade and perturbing local and global food availability, quantified in terms of virtual water. We analyze here the possible effects of local crises by developing a new propagation model, parsimonious but grounded on data-based and statistically-verified assumptions, whose effectiveness is proved on the Argentinean crisis in 2008-09. The model serves as the basis to propose indicators of crisis impact and country vulnerability to external food-production crises, which highlight that countries with largest water resources have the highest impact on the international trade, and that not only water-scarce but also wealthy and globalized countries are among the most vulnerable to external crises. The temporal analysis reveals that global average vulnerability has increased over time and that stronger effects of crises are now found in countries with low food (and water) availability.

  15. Effects of Aging on Cortical Neural Dynamics and Local Sleep Homeostasis in Mice.

    Science.gov (United States)

    McKillop, Laura E; Fisher, Simon P; Cui, Nanyi; Peirson, Stuart N; Foster, Russell G; Wafford, Keith A; Vyazovskiy, Vladyslav V

    2018-04-18

    Healthy aging is associated with marked effects on sleep, including its daily amount and architecture, as well as the specific EEG oscillations. Neither the neurophysiological underpinnings nor the biological significance of these changes are understood, and crucially the question remains whether aging is associated with reduced sleep need or a diminished capacity to generate sufficient sleep. Here we tested the hypothesis that aging may affect local cortical networks, disrupting the capacity to generate and sustain sleep oscillations, and with it the local homeostatic response to sleep loss. We performed chronic recordings of cortical neural activity and local field potentials from the motor cortex in young and older male C57BL/6J mice, during spontaneous waking and sleep, as well as during sleep after sleep deprivation. In older animals, we observed an increase in the incidence of non-rapid eye movement sleep local field potential slow waves and their associated neuronal silent (OFF) periods, whereas the overall pattern of state-dependent cortical neuronal firing was generally similar between ages. Furthermore, we observed that the response to sleep deprivation at the level of local cortical network activity was not affected by aging. Our data thus suggest that the local cortical neural dynamics and local sleep homeostatic mechanisms, at least in the motor cortex, are not impaired during healthy senescence in mice. This indicates that powerful protective or compensatory mechanisms may exist to maintain neuronal function stable across the life span, counteracting global changes in sleep amount and architecture. SIGNIFICANCE STATEMENT The biological significance of age-dependent changes in sleep is unknown but may reflect either a diminished sleep need or a reduced capacity to generate deep sleep stages. As aging has been linked to profound disruptions in cortical sleep oscillations and because sleep need is reflected in specific patterns of cortical activity, we

  16. The Influence of Local Governance: Effects on the Sustainability of Bioenergy Innovation

    Directory of Open Access Journals (Sweden)

    Bianca Cavicchi

    2017-03-01

    Full Text Available This paper deals with processes and outcomes of sustainable bioenergy development in Emilia Romagna. It draws on an on-going research project concerning inclusive innovation in forest-based bioenergy and biogas in Norway, Sweden, Finland and Italy. The goal is to explore how local governance impacts on inclusive innovation processes and triple bottom sustainability of bioenergy development in Emilia Romagna and, ultimately, to contribute to the debate on the bioeconomy. It thus compares the case of biogas and forest-based bioenergy production. The study adopts an analytical framework called Grounded Innovation (GRIP and the local governance approach. The study uses qualitative methods and particularly semi-structured interviews and governance analysis. The key results show different outcomes on both inclusive innovation and triple bottom-line dimensions. Biogas has not fostered inclusiveness and triple bottom line sustainability benefits, contrary to forest-based bioenergy. The findings indicate that the minor role of local actors, particularly municipalities, in favour of industrial and national interests may jeopardise the sustainability of biobased industries. Besides, policies limited to financial incentives may lead to a land-acquisition rush, unforeseen local environmental effects and exacerbate conflicts.

  17. Effect of local atomic and electronic structures on thermoelectric properties of chemically substituted CoSi

    Science.gov (United States)

    Hsu, C. C.; Pao, C. W.; Chen, J. L.; Chen, C. L.; Dong, C. L.; Liu, Y. S.; Lee, J. F.; Chan, T. S.; Chang, C. L.; Kuo, Y. K.; Lue, C. S.

    2014-05-01

    We report the effects of Ge partial substitution for Si on local atomic and electronic structures of thermoelectric materials in binary compound cobalt monosilicides (\\text{CoSi}_{1-x}\\text{Ge}_{x}\\text{:}\\ 0 \\le x \\le 0.15 ). Correlations between local atomic/electronic structure and thermoelectric properties are investigated by means of X-ray absorption spectroscopy. The spectroscopic results indicate that as Ge is partially substituted onto Si sites at x \\le 0.05 , Co in CoSi1-xGex gains a certain amount of charge in its 3d orbitals. Contrarily, upon further replacing Si with Ge at x \\ge 0.05 , the Co 3d orbitals start to lose some of their charge. Notably, thermopower is strongly correlated with charge redistribution in the Co 3d orbital, and the observed charge transfer between Ge and Co is responsible for the variation of Co 3d occupancy number. In addition to Seebeck coefficient, which can be modified by tailoring the Co 3d states, local lattice disorder may also be beneficial in enhancing the thermoelectric properties. Extended X-ray absorption fine structure spectrum results further demonstrate that the lattice phonons can be enhanced by Ge doping, which results in the formation of the disordered Co-Co pair. Improvements in the thermoelectric properties are interpreted based on the variation of local atomic and electronic structure induced by lattice distortion through chemical substitution.

  18. The effects of local culture on hospital administration in West Sumatra, Indonesia.

    Science.gov (United States)

    Semiarty, Rima; Fanany, Rebecca

    2017-02-06

    Purpose Problems in health-care leadership are serious in West Sumatra, Indonesia, especially in hospitals, which are controlled locally. The purpose of this paper is to present the experience of three hospitals in balancing the conflicting demands of the national health-care system and the traditional model of leadership in the local community. Design/methodology/approach Three case studies of the hospital leadership dynamic in West Sumatra were developed from in-depth interviews with directors, senior administrators and a representative selection of employees in various professional categories. Findings An analysis of findings shows that traditional views about leadership remain strong in the community and color the expectations of hospital staff. Hospital directors, however, are bound by the modern management practices of the national system. This conflict has intensified since regional autonomy which emphasizes the local culture much more than in the past. Research limitations/implications The research was carried out in one Indonesian province and was limited to three hospitals of different types. Practical implications The findings elucidate a potential underlying cause of problems in hospital management in Indonesia and may inform culturally appropriate ways of addressing them. Originality/value The social and cultural contexts of management have not been rigorously studied in Indonesia. The relationship between local and national culture reported here likely has a similar effect in other parts of the country.

  19. Norskov and the Logic of Place: The Soft Effect of Local Danish TV Drama Production

    Directory of Open Access Journals (Sweden)

    Kim Toft Hansen

    2017-07-01

    Full Text Available In this article, we analyse locality and locations in recent Danish TV crime drama with the series Norskov as a representative case. The series’ mode of production is rooted in the Danish broadcaster TV 2’s regional obligations and it illustrates a broader tendency in local TV drama production. The article introduces the concepts intertextual consciousness, stories from below and cartographic branding, and refers to the notion of re-imagined communities as a local administrative result of drama production and broadcast. The findings of the article are based on production and location analyses with primary focus on the series’ preproduction stage as well as empirical data material such as interviews, documents from the production process and material from the municipality of Frederikshavn (the location of Norskov, manuscript versions, and textual and visual material from the cinematographer and the location manager. Finally, the article combines provinciality and the notion of re-imagined communities in order to evaluate the effect of local drama production.

  20. Local anesthetic effect of docosahexaenoic acid on the nociceptive jaw-opening reflex in rats.

    Science.gov (United States)

    Mitome, Kazuki; Takehana, Shiori; Oshima, Katsuo; Shimazu, Yoshihito; Takeda, Mamoru

    2018-02-23

    Although docosahexaenoic acid (DHA) administration suppresses sodium channels in primary afferent sensory neurons, the acute local effect of DHA on the trigeminal nociceptive reflex remains to be elucidated, in vivo. Therefore, the aim of the present study was to investigate whether local administration of DHA attenuates the nociceptive jaw-opening reflex (JOR) in vivo in the rat. The JOR evoked by electrical stimulation of the tongue was recorded by a digastric muscle electromyogram (dEMG) in pentobarbital-anesthetized rats. The amplitude of the dEMG response was significantly increased in proportion to the electrical stimulation intensity (1-5 x threshold). At 3 x threshold, local administration of DHA (0.1, 10 and 25 mM) dose-dependently inhibited the dEMG response, and lasted 40 min. Maximum inhibition of the dEMG signal amplitude was seen within approximately 10 min. The mean magnitude of inhibition of the dEMG signal amplitude by DHA (25 mM) was almost equal to the local anesthetic, 1% lidocaine (37 mM), a sodium channel blocker. These findings suggest that DHA attenuates the nociceptive JOR via possibly blocking sodium channels, and strongly support the idea that DHA is a potential therapeutic agent and complementary alternative medicine for the prevention of acute trigeminal nociception. Copyright © 2018 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.

  1. Effect of laser beam filamentation on plasma wave localization and stimulated Raman scattering

    International Nuclear Information System (INIS)

    Purohit, Gunjan; Sharma, R. P.

    2013-01-01

    This paper presents the effect of laser beam filamentation on the localization of electron plasma wave (EPW) and stimulated Raman scattering (SRS) in unmagnitized plasma when both relativistic and ponderomotive nonlinearities are operative. The filamentary dynamics of laser beam is studied and the splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. The localization of electron plasma wave takes place due to nonlinear coupling between the laser beam and EPW. Stimulated Raman scattering of this EPW is studied and backreflectivity has been calculated. The localization of EPW also affects the eigenfrequency and damping of plasma wave; consequently, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the backreflectivity. The new enhanced damping of the plasma wave has been calculated and it is found that the SRS process gets suppressed due to the localization of plasma wave in laser beam filamentary structures. For typical laser beam and plasma parameters with wavelength λ (=1064 nm), power flux (=10 16 W/cm 2 ) and plasma density (n/n cr ) = 0.2; the SRS back reflectivity is found to be suppressed by a factor of around 5%. (author)

  2. The effect of unemployment, aggregate wages, and spatial contiguity on local wages: An investigation with German district level data

    OpenAIRE

    Thiess Buettner

    1999-01-01

    Despite spatial rigidity of collectively negotiated wages the local unemployment rate is found to have a significant negative impact on wages. This impact is shown to be consistent with both the wage-curve hypothesis and modern Phillips-curve modelling. Spatial contiguity effects are found in wages and unemployment and their neglect leads to an underestimation of the effect of local unemployment. Yet, the impact of local unemployment on wages turns out to be quite low as compared to studies f...

  3. Local lattice relaxations in random metallic alloys: Effective tetrahedron model and supercell approach

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Shallcross, S.

    2003-01-01

    We present a simple effective tetrahedron model for local lattice relaxation effects in random metallic alloys on simple primitive lattices. A comparison with direct ab initio calculations for supercells representing random Ni0.50Pt0.50 and Cu0.25Au0.75 alloys as well as the dilute limit of Au-ri......-rich CuAu alloys shows that the model yields a quantitatively accurate description of the relaxtion energies in these systems. Finally, we discuss the bond length distribution in random alloys....

  4. On the gauge invariant and topological nature of the localization determining the Quantum Hall Effect plateaus

    CERN Document Server

    Cabo-Montes de Oca, Alejandro

    2002-01-01

    It is shown how the electromagnetic response of 2DEG under Quantum Hall Effect regime, characterized by the Chern-Simons topological action, transforms the sample impurities and defects in charge-reservoirs that stabilize the Hall conductivity plateaus. The results determine the basic dynamical origin of the singular properties of localization under the occurrence of the Quantum Hall Effect obtained in the pioneering works of Laughlin and of Joynt and Prange, by means of a gauge invariance argument and a purely electronic analysis, respectively. The common intuitive picture of electrons moving along the equipotential lines gets an analytical realization through the Chern-Simons current and charge densities.

  5. Perceived local enforcement, personal beliefs,and underage drinking: an assessment of moderating and main effects.

    Science.gov (United States)

    Lipperman-Kreda, Sharon; Paschall, Mallie J; Grube, Joel W

    2009-01-01

    Strategies to enforce underage drinking laws are aimed at reducing youth access to alcohol from commercial and social sources and deterring its possession and use. However, the processes through which enforcement strategies may affect underage drinking are not well understood. This study examined three possible processes by which perceived enforcement of underage drinking laws and personal beliefs (perceived alcohol availability, perceived harm, and personal disapproval of alcohol use) may influence alcohol use among adolescents. Survey data were obtained from 20,747 adolescents (48.3% males) in 115 school districts who participated in the 2006 Oregon Healthy Teens survey. Linear regression analyses were conducted to examine possible interactive and main effects of perceived enforcement and personal beliefs on past-30-day alcohol use. Analyses were adjusted for clustering of observations within school districts and included student demographics and age of alcohol use initiation as covariates. Statistically significant interaction effects on past-30-day alcohol use were found for perceived police enforcement and the three personal beliefs variables, indicating weaker associations between personal beliefs and past-30-day alcohol use at higher levels of perceived enforcement. Main effects of perceived enforcement and personal beliefs variables were also observed in the presence of interaction effects. Evidence for a moderating effect of perceived local enforcement on the relationships between personal beliefs and drinking behaviors suggests that the combination of individually focused prevention programs and local enforcement of underage drinking laws may have the greatest impact on underage drinking.

  6. A general relativistic signature in the galaxy bispectrum: the local effects of observing on the lightcone

    Energy Technology Data Exchange (ETDEWEB)

    Umeh, Obinna; Jolicoeur, Sheean; Maartens, Roy [Department of Physics and Astronomy, University of the Western Cape, Robert Sobukwe Road, Cape Town 7535 (South Africa); Clarkson, Chris, E-mail: umeobinna@gmail.com, E-mail: beautifulheart369@gmail.com, E-mail: roy.maartens@gmail.com, E-mail: chris.clarkson@gmail.com [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2017-03-01

    Next-generation galaxy surveys will increasingly rely on the galaxy bispectrum to improve cosmological constraints, especially on primordial non-Gaussianity. A key theoretical requirement that remains to be developed is the analysis of general relativistic effects on the bispectrum, which arise from observing galaxies on the past lightcone, as well as from relativistic corrections to the dynamics. As an initial step towards a fully relativistic analysis of the galaxy bispectrum, we compute for the first time the local relativistic lightcone effects on the bispectrum, which come from Doppler and gravitational potential contributions. For the galaxy bispectrum, the problem is much more complex than for the power spectrum, since we need the lightcone corrections at second order. Mode-coupling contributions at second order mean that relativistic corrections can be non-negligible at smaller scales than in the case of the power spectrum. In a primordial Gaussian universe, we show that the local lightcone projection effects for squeezed shapes at z ∼ 1 mean that the bispectrum can differ from the Newtonian prediction by ∼> 10% when the short modes are k ∼< (50 Mpc){sup −1}. These relativistic projection effects, if ignored in the analysis of observations, could be mistaken for primordial non-Gaussianity. For upcoming surveys which probe equality scales and beyond, all relativistic lightcone effects and relativistic dynamical corrections should be included for an accurate measurement of primordial non-Gaussianity.

  7. Effect of conductor geometry on source localization: Implications for epilepsy studies

    International Nuclear Information System (INIS)

    Schlitt, H.; Heller, L.; Best, E.; Ranken, D.; Aaron, R.

    1994-01-01

    We shall discuss the effects of conductor geometry on source localization for applications in epilepsy studies. The most popular conductor model for clinical MEG studies is a homogeneous sphere. However, several studies have indicated that a sphere is a poor model for the head when the sources are deep, as is the case for epileptic foci in the mesial temporal lobe. We believe that replacing the spherical model with a more realistic one in the inverse fitting procedure will improve the accuracy of localizing epileptic sources. In order to include a realistic head model in the inverse problem, we must first solve the forward problem for the realistic conductor geometry. We create a conductor geometry model from MR images, and then solve the forward problem via a boundary integral equation for the electric potential due to a specified primary source. One the electric potential is known, the magnetic field can be calculated directly. The most time-intensive part of the problem is generating the conductor model; fortunately, this needs to be done only once for each patient. It takes little time to change the primary current and calculate a new magnetic field for use in the inverse fitting procedure. We present the results of a series of computer simulations in which we investigate the localization accuracy due to replacing the spherical model with the realistic head model in the inverse fitting procedure. The data to be fit consist of a computer generated magnetic field due to a known current dipole in a realistic head model, with added noise. We compare the localization errors when this field is fit using a spherical model to the fit using a realistic head model. Using a spherical model is comparable to what is usually done when localizing epileptic sources in humans, where the conductor model used in the inverse fitting procedure does not correspond to the actual head

  8. Training NOAA Staff on Effective Communication Methods with Local Climate Users

    Science.gov (United States)

    Timofeyeva, M. M.; Mayes, B.

    2011-12-01

    Since 2002 NOAA National Weather Service (NWS) Climate Services Division (CSD) offered training opportunities to NWS staff. As a result of eight-year-long development of the training program, NWS offers three training courses and about 25 online distance learning modules covering various climate topics: climate data and observations, climate variability and change, NWS national and local climate products, their tools, skill, and interpretation. Leveraging climate information and expertise available at all NOAA line offices and partners allows delivery of the most advanced knowledge and is a very critical aspect of the training program. NWS challenges in providing local climate services includes effective communication techniques on provide highly technical scientific information to local users. Addressing this challenge requires well trained, climate-literate workforce at local level capable of communicating the NOAA climate products and services as well as provide climate-sensitive decision support. Trained NWS climate service personnel use proactive and reactive approaches and professional education methods in communicating climate variability and change information to local users. Both scientifically-unimpaired messages and amiable communication techniques such as story telling approach are important in developing an engaged dialog between the climate service providers and users. Several pilot projects NWS CSD conducted in the past year applied the NWS climate services training program to training events for NOAA technical user groups. The technical user groups included natural resources managers, engineers, hydrologists, and planners for transportation infrastructure. Training of professional user groups required tailoring the instructions to the potential applications of each group of users. Training technical user identified the following critical issues: (1) Knowledge of target audience expectations, initial knowledge status, and potential use of climate

  9. Estimating the Cumulative Ecological Effect of Local Scale Landscape Changes in South Florida

    Science.gov (United States)

    Hogan, Dianna M.; Labiosa, William; Pearlstine, Leonard; Hallac, David; Strong, David; Hearn, Paul; Bernknopf, Richard

    2012-01-01

    Ecosystem restoration in south Florida is a state and national priority centered on the Everglades wetlands. However, urban development pressures affect the restoration potential and remaining habitat functions of the natural undeveloped areas. Land use (LU) planning often focuses at the local level, but a better understanding of the cumulative effects of small projects at the landscape level is needed to support ecosystem restoration and preservation. The South Florida Ecosystem Portfolio Model (SFL EPM) is a regional LU planning tool developed to help stakeholders visualize LU scenario evaluation and improve communication about regional effects of LU decisions. One component of the SFL EPM is ecological value (EV), which is evaluated through modeled ecological criteria related to ecosystem services using metrics for (1) biodiversity potential, (2) threatened and endangered species, (3) rare and unique habitats, (4) landscape pattern and fragmentation, (5) water quality buffer potential, and (6) ecological restoration potential. In this article, we demonstrate the calculation of EV using two case studies: (1) assessing altered EV in the Biscayne Gateway area by comparing 2004 LU to potential LU in 2025 and 2050, and (2) the cumulative impact of adding limestone mines south of Miami. Our analyses spatially convey changing regional EV resulting from conversion of local natural and agricultural areas to urban, industrial, or extractive use. Different simulated local LU scenarios may result in different alterations in calculated regional EV. These case studies demonstrate methods that may facilitate evaluation of potential future LU patterns and incorporate EV into decision making.

  10. Local density regulates migratory songbird reproductive success through effects on double-brooding and nest predation.

    Science.gov (United States)

    Woodworth, Bradley K; Wheelwright, Nathaniel T; Newman, Amy E M; Norris, D Ryan

    2017-08-01

    Knowledge of the density-dependent processes that regulate animal populations is key to understanding, predicting, and conserving populations. In migratory birds, density-dependence is most often studied during the breeding season, yet we still lack a robust understanding of the reproductive traits through which density influences individual reproductive success. We used 27-yr of detailed, individual-level productivity data from an island-breeding population of Savannah sparrows Passerculus sandwichensis to evaluate effects of local and total annual population density on female reproductive success. Local density (number of neighbors within 50 m of a female's nest) had stronger effects on the number of young fledged than did total annual population density. Females nesting in areas of high local density were more likely to suffer nest predation and less likely to initiate and fledge a second clutch, which led to fewer young fledged in a season. Fledging fewer young subsequently decreased the likelihood of a female recruiting offspring into the breeding population in a subsequent year. Collectively, these results provide insight into the scale and reproductive mechanisms mediating density-dependent reproductive success and fitness in songbirds. © 2017 by the Ecological Society of America.

  11. Applicability and Effectiveness of Closed Reduction of Nasal Fractures under Local Anesthesia

    Directory of Open Access Journals (Sweden)

    Vilela, Fernando

    2014-03-01

    Full Text Available Introduction A significant portion of patients treated in emergency departments have nasal fracture. It is important that the otolaryngologist know how to treat such damage. Objectives To evaluate the effectiveness of nasal fracture reduction under local anesthesia and tolerance to the procedure. Methods Twenty-four patients treated in the emergency department with closed reduction under local anesthesia were prospectively followed. Epidemiologic information and data regarding pain and complications during the management were noted. The degree of satisfaction was researched by visual analog scale. Results The majority of patients were male (75%, and the most common cause of injury was motor vehicle accident. We found a significant association between time to reduction and referred pain during the procedure. In patients in whom the procedure was delayed (over 3 days, there was less pain, and those who bled during the procedure had a shorter average time to reduction than the group of patients who did not bleed. Most patients were very satisfied, with more than 95% of these willing to undergo the same process again, if necessary. Conclusions The closed approach in the clinic under local anesthesia was effective and safe in restoration of the nose.

  12. The effect of short ground vegetation on terrestrial laser scans at a local scale

    Science.gov (United States)

    Fan, Lei; Powrie, William; Smethurst, Joel; Atkinson, Peter M.; Einstein, Herbert

    2014-09-01

    Terrestrial laser scanning (TLS) can record a large amount of accurate topographical information with a high spatial accuracy over a relatively short period of time. These features suggest it is a useful tool for topographical survey and surface deformation detection. However, the use of TLS to survey a terrain surface is still challenging in the presence of dense ground vegetation. The bare ground surface may not be illuminated due to signal occlusion caused by vegetation. This paper investigates vegetation-induced elevation error in TLS surveys at a local scale and its spatial pattern. An open, relatively flat area vegetated with dense grass was surveyed repeatedly under several scan conditions. A total station was used to establish an accurate representation of the bare ground surface. Local-highest-point and local-lowest-point filters were applied to the point clouds acquired for deriving vegetation height and vegetation-induced elevation error, respectively. The effects of various factors (for example, vegetation height, edge effects, incidence angle, scan resolution and location) on the error caused by vegetation are discussed. The results are of use in the planning and interpretation of TLS surveys of vegetated areas.

  13. An assessment of the effects of local government organisation on air quality management practices

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, C.I.; Ling, K.; Longhurst, J.W.S. [Univ. of the West of England, Faculty of Applied Sciences, Bristol (GB)] [and others

    1999-07-01

    During the last 15 years, local government in the UK has been undergoing a series of reorganisations, leaving a legacy of different organisational structures. In England, local government is essentially structured in two contrasting ways. In some areas a single all-purpose council is responsible for all local authority functions (unitary, metropolitan or London boroughs) with the remainder in a two tier system in which two separate councils divide responsibilities between district and county councils. The Local Air Quality Management (LAQM) process, the method of air pollution control currently underway in the UK, is led by central Government guidance. It is only required of local authorities 'to have regard to this guidance'. It is therefore expected that there will be considerable variation in the interpretation and approach taken, within the framework set out by the guidance. It is hypothesised that the different local government organisational structures will approach their LAQM activities in a variety of styles. Within all-purpose councils, communication should be easier than within two tier councils. By the same argument, the length of time these 'unitary' councils have been in place should also affect LAQM practices through communication routes. London boroughs and metropolitan boroughs have had responsibility for all functions within their area for well over 10 years. In contrast, unitary authorities have more recently taken over these extra roles (such as transport planning) and so effective and efficient internal communication routes may not yet be in place. 14 unitary authorities were created in 1992 and a further 32 have come into being in either 1997 or 1998. This paper investigates whether the organisational structure of a local authority does have a significant impact on LAQM practices. It concluded that single-tier authorities do appear to be further ahead in the LAQM process. However, it is unknown from the evidence presented

  14. Mild focal cerebral ischemia in the rat. The effect of local temperature on infarct size

    DEFF Research Database (Denmark)

    Hildebrandt-Eriksen, Elisabeth S; Christensen, Thomas; Diemer, Nils Henrik

    2002-01-01

    . The effect of local temperature at the occlusion site in this model was furthermore tested. Thirty-three Wistar rats were subjected to 30 min of simultaneous common carotid artery and distal middle cerebral artery occlusion or sham treatment. Animals were magnetic resonance-scanned repeatedly between day one...... and day 14 after surgery, then sacrificed, and paraffin brain sections stained. All animals scanned 24 h after reperfusion showed an area of edema in the affected cortex, which later was identified as an infarct. Animals with a temperature of 33.9 +/- 1.5 degrees C at the MCA site (hypothermic) showed...... smaller infarcts (14.4 +/- 10 mm3) than animals with normothermic local temperature (36.7 +/- 0.2 degrees C, 57.7 +/- 26.4 mm3). Infarct size was maximal on day 3 after ischemia but decreased as edema subsided. Infarct volumes from histology and magnetic resonance imaging correlated well. The model...

  15. Effect of Local Junction Losses in the Optimization of T-shaped Flow Channels

    Science.gov (United States)

    Kosaraju, Srinivas

    2015-11-01

    T-shaped channels are extensively used in flow distribution applications such as irrigation, chemical dispersion, gas pipelines and space heating and cooling. The geometry of T-shaped channels can be optimized to reduce the overall pressure drop in stem and branch sections. Results of such optimizations are in the form of geometric parameters such as the length and diameter ratios of the stem and branch sections. The traditional approach of this optimization accounts for the pressure drop across the stem and branch sections, however, ignores the pressure drop in the T-junction. In this paper, we conduct geometry optimization while including the effect of local junction losses in laminar flows. From the results, we are able to identify a non-dimensional parameter that can be used to predict the optimal geometric configurations. This parameter can also be used to identify the conditions in which the local junction losses can be ignored during the optimization.

  16. Effect of eddy current damping on phononic band gaps generated by locally resonant periodic structures

    Science.gov (United States)

    Ozkaya, Efe; Yilmaz, Cetin

    2017-02-01

    The effect of eddy current damping on a novel locally resonant periodic structure is investigated. The frequency response characteristics are obtained by using a lumped parameter and a finite element model. In order to obtain wide band gaps at low frequencies, the periodic structure is optimized according to certain constraints, such as mass distribution in the unit cell, lower limit of the band gap, stiffness between the components in the unit cell, the size of magnets used for eddy current damping, and the number of unit cells in the periodic structure. Then, the locally resonant periodic structure with eddy current damping is manufactured and its experimental frequency response is obtained. The frequency response results obtained analytically, numerically and experimentally match quite well. The inclusion of eddy current damping to the periodic structure decreases amplitudes of resonance peaks without disturbing stop band width.

  17. Controlling effect of geometrically defined local structural changes on chaotic Hamiltonian systems.

    Science.gov (United States)

    Ben Zion, Yossi; Horwitz, Lawrence

    2010-04-01

    An effective characterization of chaotic conservative Hamiltonian systems in terms of the curvature associated with a Riemannian metric tensor derived from the structure of the Hamiltonian has been extended to a wide class of potential models of standard form through definition of a conformal metric. The geodesic equations reproduce the Hamilton equations of the original potential model through an inverse map in the tangent space. The second covariant derivative of the geodesic deviation in this space generates a dynamical curvature, resulting in (energy-dependent) criteria for unstable behavior different from the usual Lyapunov criteria. We show here that this criterion can be constructively used to modify locally the potential of a chaotic Hamiltonian model in such a way that stable motion is achieved. Since our criterion for instability is local in coordinate space, these results provide a minimal method for achieving control of a chaotic system.

  18. Effectiveness of local vancomycin powder to decrease surgical site infections: a meta-analysis.

    Science.gov (United States)

    Chiang, Hsiu-Yin; Herwaldt, Loreen A; Blevins, Amy E; Cho, Edward; Schweizer, Marin L

    2014-03-01

    Some surgeons use systemic vancomycin to prevent surgical site infections (SSIs), but patients who do not carry methicillin-resistant Staphylococcus aureus have an increased risk of SSIs when given vancomycin alone for intravenous prophylaxis. Applying vancomycin powder to the wound before closure could increase the local tissue vancomycin level without significant systemic levels. However, the effectiveness of local vancomycin powder application for preventing SSIs has not been established. Our objective was to systematically review and evaluate studies on the effectiveness of local vancomycin powder for decreasing SSIs. Meta-analysis. We included observational studies, quasi-experimental studies, and randomized controlled trials of patients undergoing surgical procedures that involved vancomycin powder application to surgical wounds, reported SSI rates, and had a comparison group that did not use local vancomycin powder. The primary outcome was postoperative SSIs. The secondary outcomes included deep incisional SSIs and S. aureus SSIs. We performed systematic literature searches in PubMed, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Cochrane Central Register of Controlled Trials via Wiley, Scopus (including EMBASE abstracts), Web of Science, ClinicalTrials.gov, BMC Proceedings, ProQuest Dissertation, and Thesis in Health and Medicine, and conference abstracts from IDWeek, the Interscience Conference on Antimicrobial Agents and Chemotherapy, the Society for Healthcare Epidemiology of America, and the American Academy of Orthopedic Surgeons annual meetings, and also the Scoliosis Research Society Annual Meeting and Course. We ran the searches from inception on May 9, 2013 with no limits on date or language. After reviewing 373 titles or abstracts and 22 articles in detail, we included 10 independent studies and used a random-effects model when pooling risk estimates to assess the effectiveness of local

  19. Silicate melts density, buoyancy relations and the dynamics of magmatic processes in the upper mantle

    Science.gov (United States)

    Sanchez-Valle, Carmen; Malfait, Wim J.

    2016-04-01

    with results from ab initio calculations. The density model has been applied to examine the mineral-melt buoyancy relations at depth and the implications of these results for the dynamics of magma chambers, crystal settling and the stability and mobility of magmas in the upper mantle will be discussed.

  20. Local versus landscape-scale effects of anthropogenic land-use on forest species richness

    Science.gov (United States)

    Buffa, G.; Del Vecchio, S.; Fantinato, E.; Milano, V.

    2018-01-01

    The study investigated the effects of human-induced landscape patterns on species richness in forests. For 80 plots of fixed size, we measured human disturbance (categorized as urban/industrial and agricultural land areas), at 'local' and 'landscape' scale (500 m and 2500 m radius from each plot, respectively), the distance from the forest edge, and the size and shape of the woody patch. By using GLM, we analyzed the effects of disturbance and patch-based measures on both total species richness and the richness of a group of specialist species (i.e. the 'ancient forest species'), representing more specific forest features. Patterns of local species richness were sensitive to the structure and composition of the surrounding landscape. Among the landscape components taken into account, urban/industrial land areas turned out as the most threatening factor for both total species richness and the richness of the ancient forest species. However, the best models evidenced a different intensity of the response to the same disturbance category as well as a different pool of significant variables for the two groups of species. The use of groups of species, such as the ancient forest species pool, that are functionally related and have similar ecological requirements, may represent an effective solution for monitoring forest dynamics under the effects of external factors. The approach of relating local assessment of species richness, and in particular of the ancient forest species pool, to land-use patterns may play an important role for the science-policy interface by supporting and strengthening conservation and regional planning decision making.

  1. Transition, coexistence, and interaction of vector localized waves arising from higher-order effects

    International Nuclear Information System (INIS)

    Liu, Chong; Yang, Zhan-Ying; Zhao, Li-Chen; Yang, Wen-Li

    2015-01-01

    We study vector localized waves on continuous wave background with higher-order effects in a two-mode optical fiber. The striking properties of transition, coexistence, and interaction of these localized waves arising from higher-order effects are revealed in combination with corresponding modulation instability (MI) characteristics. It shows that these vector localized wave properties have no analogues in the case without higher-order effects. Specifically, compared to the scalar case, an intriguing transition between bright–dark rogue waves and w-shaped–anti-w-shaped solitons, which occurs as a result of the attenuation of MI growth rate to vanishing in the zero-frequency perturbation region, is exhibited with the relative background frequency. In particular, our results show that the w-shaped–anti-w-shaped solitons can coexist with breathers, coinciding with the MI analysis where the coexistence condition is a mixture of a modulation stability and MI region. It is interesting that their interaction is inelastic and describes a fusion process. In addition, we demonstrate an annihilation phenomenon for the interaction of two w-shaped solitons which is identified essentially as an inelastic collision in this system. -- Highlights: •Vector rogue wave properties induced by higher-order effects are studied. •A transition between vector rogue waves and solitons is obtained. •The link between the transition and modulation instability (MI) is demonstrated. •The coexistence of vector solitons and breathers coincides with the MI features. •An annihilation phenomenon for the vector two w-shaped solitons is presented.

  2. Transition, coexistence, and interaction of vector localized waves arising from higher-order effects

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chong [School of Physics, Northwest University, Xi’an 710069 (China); Yang, Zhan-Ying, E-mail: zyyang@nwu.edu.cn [School of Physics, Northwest University, Xi’an 710069 (China); Zhao, Li-Chen, E-mail: zhaolichen3@163.com [School of Physics, Northwest University, Xi’an 710069 (China); Yang, Wen-Li [Institute of Modern Physics, Northwest University, Xi’an 710069 (China)

    2015-11-15

    We study vector localized waves on continuous wave background with higher-order effects in a two-mode optical fiber. The striking properties of transition, coexistence, and interaction of these localized waves arising from higher-order effects are revealed in combination with corresponding modulation instability (MI) characteristics. It shows that these vector localized wave properties have no analogues in the case without higher-order effects. Specifically, compared to the scalar case, an intriguing transition between bright–dark rogue waves and w-shaped–anti-w-shaped solitons, which occurs as a result of the attenuation of MI growth rate to vanishing in the zero-frequency perturbation region, is exhibited with the relative background frequency. In particular, our results show that the w-shaped–anti-w-shaped solitons can coexist with breathers, coinciding with the MI analysis where the coexistence condition is a mixture of a modulation stability and MI region. It is interesting that their interaction is inelastic and describes a fusion process. In addition, we demonstrate an annihilation phenomenon for the interaction of two w-shaped solitons which is identified essentially as an inelastic collision in this system. -- Highlights: •Vector rogue wave properties induced by higher-order effects are studied. •A transition between vector rogue waves and solitons is obtained. •The link between the transition and modulation instability (MI) is demonstrated. •The coexistence of vector solitons and breathers coincides with the MI features. •An annihilation phenomenon for the vector two w-shaped solitons is presented.

  3. Shear localization and effective wall friction in a wall bounded granular flow

    Science.gov (United States)

    Artoni, Riccardo; Richard, Patrick

    2017-06-01

    In this work, granular flow rheology is investigated by means of discrete numerical simulations of a torsional, cylindrical shear cell. Firstly, we focus on azimuthal velocity profiles and study the effect of (i) the confining pressure, (ii) the particle-wall friction coefficient, (iii) the rotating velocity of the bottom wall and (iv) the cell diameter. For small cell diameters, azimuthal velocity profiles are nearly auto-similar, i.e. they are almost linear with the radial coordinate. Different strain localization regimes are observed : shear can be localized at the bottom, at the top of the shear cell, or it can be even quite distributed. This behavior originates from the competition between dissipation at the sidewalls and dissipation in the bulk of the system. Then we study the effective friction at the cylindrical wall, and point out the strong link between wall friction, slip and fluctuations of forces and velocities. Even if the system is globally below the sliding threshold, force fluctuations trigger slip events, leading to a nonzero wall slip velocity and an effective wall friction coefficient different from the particle-wall one. A scaling law was found linking slip velocity, granular temperature in the main flow direction and effective friction. Our results suggest that fluctuations are an important ingredient for theories aiming to capture the interface rheology of granular materials.

  4. Cost-effectiveness on a local level: whether and when to adopt a new technology.

    Science.gov (United States)

    Woertman, Willem H; Van De Wetering, Gijs; Adang, Eddy M M

    2014-04-01

    Cost-effectiveness analysis has become a widely accepted tool for decision making in health care. The standard textbook cost-effectiveness analysis focuses on whether to make the switch from an old or common practice technology to an innovative technology, and in doing so, it takes a global perspective. In this article, we are interested in a local perspective, and we look at the questions of whether and when the switch from old to new should be made. A new approach to cost-effectiveness from a local (e.g., a hospital) perspective, by means of a mathematical model for cost-effectiveness that explicitly incorporates time, is proposed. A decision rule is derived for establishing whether a new technology should be adopted, as well as a general rule for establishing when it pays to postpone adoption by 1 more period, and a set of decision rules that can be used to determine the optimal timing of adoption. Finally, a simple example is presented to illustrate our model and how it leads to optimal decision making in a number of cases.

  5. Estimation of effective brain connectivity with dual Kalman filter and EEG source localization methods.

    Science.gov (United States)

    Rajabioun, Mehdi; Nasrabadi, Ali Motie; Shamsollahi, Mohammad Bagher

    2017-09-01

    Effective connectivity is one of the most important considerations in brain functional mapping via EEG. It demonstrates the effects of a particular active brain region on others. In this paper, a new method is proposed which is based on dual Kalman filter. In this method, firstly by using a brain active localization method (standardized low resolution brain electromagnetic tomography) and applying it to EEG signal, active regions are extracted, and appropriate time model (multivariate autoregressive model) is fitted to extracted brain active sources for evaluating the activity and time dependence between sources. Then, dual Kalman filter is used to estimate model parameters or effective connectivity between active regions. The advantage of this method is the estimation of different brain parts activity simultaneously with the calculation of effective connectivity between active regions. By combining dual Kalman filter with brain source localization methods, in addition to the connectivity estimation between parts, source activity is updated during the time. The proposed method performance has been evaluated firstly by applying it to simulated EEG signals with interacting connectivity simulation between active parts. Noisy simulated signals with different signal to noise ratios are used for evaluating method sensitivity to noise and comparing proposed method performance with other methods. Then the method is applied to real signals and the estimation error during a sweeping window is calculated. By comparing proposed method results in different simulation (simulated and real signals), proposed method gives acceptable results with least mean square error in noisy or real conditions.

  6. QUALITY, EFFECTIVENESS AND MANAGEMENT INFORMATION SYSTEMS PERFORMANCE OF LOCAL TREASURIES BUDGET ACCOUNTING

    Directory of Open Access Journals (Sweden)

    Biljana Tešić

    2011-09-01

    Full Text Available The role of management information systems (MIS of local treasuries budget accounting is to provide qualitative information support to management in process of decision making and to provide effective managing of key processes of budget accounting, in accordance with requests of management on all levels of decision making. From the aspect of effectiveness and request for quality, in accordance with request of users and defined system goals, this research includes the analysis of characteristics and goals of identified key processes, critical success factors (CSF, key performance indicators (KPI, standards for realization of users requests, results of processes and indicators of goals realisation. The aim of this paper, based on the results of the analysis, is to develop models for evaluation of quality and effectiveness and to define key performance indicators of MIS of budget accounting, in order to perceive the level of achievement of the goals of the system, effectiveness of processes and level of fulfillment of requirements and needs of all users groups that are significant for budge t accounting of local treasuries.

  7. Simulation of temperature effect on microalgae culture in a tubular photo bioreactor for local solar irradiance

    Science.gov (United States)

    Shahriar, M.; Deb, Ujjwal Kumar; Rahman, Kazi Afzalur

    2017-06-01

    Microalgae based biofuel is now an emerging source of renewable energy alternative to the fossil fuel. This paper aims to present computational model of microalgae culture taking effect of solar irradiance and corresponding temperature in a photo bioreactor (PBR). As microalgae is a photosynthetic microorganism, so irradiance of sunlight is one of the important limiting factors for the proper growth of microalgae cells as temperature is associated with it. We consider the transient behaviour of temperature inside the photo bioreactor for a microalgae culture. The optimum range of temperature for outdoor cultivation of microalgae is about 16-35°c and out of this range the cell growth inhibits. Many correlations have already been established to investigate the heat transfer phenomena inside a tubular PBR. However, none of them are validated yet numerically by using a user defined function in a simulated model. A horizontal tubular PBR length 20.5m with radius 0.05m has taken account to investigate the temperature effect for the growth of microalgae cell. As the solar irradiance varies at any geographic latitude for a year so an empirical relation is established between local solar irradiance and temperature to simulate the effect. From our simulation, we observed that the growth of microalgae has a significant effect of temperature and the solar irradiance of our locality is suitable for the culture of microalgae.

  8. Influence of the weighing bar size to determine optimal time of biodiesel-glycerol separation by using the buoyancy weighing-bar method

    Science.gov (United States)

    Tambun, R.; Sibagariang, Y.; Manurung, J.

    2018-02-01

    The buoyancy weighing-bar method is a novel method in the particle size distribution measurement. This method can measure particle size distributions of the settling particles and floating particles. In this study, the buoyancy weighing-bar method is applied to determine optimal time of biodiesel-glycerol separation. The buoyancy weighing-bar method can be applied to determine the separation time because biodiesel and glycerol have the different densities. The influences of diameter of weighing-bar by using the buoyancy weighing-bar method would be experimentally investigated. The diameters of weighing-bar in this experiment are 8 mm, 10 mm, 15 mm and 20 mm, while the graduated cylinder (diameter : 65 mm) is used as vessel. The samples used in this experiment are the mixture of 95 % of biodiesel and 5 % of glycerol. The data obtained by the buoyancy weighing-bar method are analized by using the gas chromatography to determine the purity of biodiesel. Based on the data obtained, the buoyancy weighing-bar method can be used to detect the separation time of biodiesel-glycerol by using the weighing-bar diameter of 8 mm, 10 mm, 15 mm and 20 mm, but the most accuracy in determination the biodiesel-glycerol separation time is obtained by using the weighing-bar diameter of 20 mm. The biodiesel purity of 97.97 % could be detected at 64 minutes by using the buoyancy weighing-bar method when the weighing-bar diameter of 20 mm is used.

  9. Shear flow beneath oceanic plates: Local nonsimilarity boundary layers for olivine rheology

    International Nuclear Information System (INIS)

    Yuen, D.A.; Tovish, A.; Schubert, G.

    1978-01-01

    The principle of local similarity, which has been used to model the two-dimensional boundary layers in the oceanic upper mantle, permits calculation of the temperature, velocity, and stress fields with essentially analytic techniques. Finite difference numerical methods are hard pressed to resolve the detail required by the large variation of viscosity between the lithosphere and the asthenosphere. In this paper the local similarity approximation has been justified by quantitatively evaluating the effect of nonsimilarity due to viscous heating, nonlinear temperature- and pressure-dependent rheology, buoyancy, adiabatic cooling, etc. Nonsimilar effects produce only small modifications of the locally similar boundary layers; important geophysical observables such as surface heat flux and ocean floor topography are given to better than 10% by the locally similar solution. A posteriori evaluations of the term neglected in the boundary layer simplification of the complete equations have been conducted on the locally similar temperature and velocity profiles close to the spreading ridge. The boundary layer models are valid to depths of 100 km at 3 m.y. and 10 km at 0.3 m.y

  10. Effects of hand massage on anxiety in patients undergoing ophthalmology surgery using local anesthesia

    Directory of Open Access Journals (Sweden)

    Jafar Rafiei Kiasari

    2012-08-01

    Full Text Available Introduction: Anxiety is a common disorder in patients before surgery. Inappropriately managed anxiety can cause psychological and physiological reactions and will affect the process of surgery and recovery. Therefore, this study examined the effects of hand mas-sage on anxiety in patients undergoing ophthalmology surgery using local anesthesia. Methods: In this interventional study, 52 patients who were supposed to undergo oph-thalmology surgery using local anesthesia were studied. Patients were randomly as-signed to two groups of intervention, who received hand massage before surgery (n = 27 and control (n = 25. Massaging lasted for 5 minutes (2.5 minutes on each hand before surgery. Stroking and scrubbing methods were performed by 2 trained research-ers. Anxiety level, blood pressure, heart rate, and respiratory rate were measured before and after the intervention in both groups. Anxiety was evaluated using Spielberger State-Trait Anxiety Inventory. Data was analyzed by chi-square, independent samples t-test, and paired t-test. Results: There were no significant differences in mean anxiety, systolic blood pressure, diastolic blood pressure, heart rate, and respiratory rate between the two groups before the intervention (p > 0.05. However, there was a significant differenc in the mean stress level between the two groups after the intervention (p 0.05. Conclusion: Our findings suggested that 5 minutes of hand massage before ophthalmology surgery (under local anesthesia could reduce anxiety. Therefore, this method can be used to increase patient comfort and reduce anxiety before surgical interventions.

  11. The Effects of Local Vibration on Balance, Power, and Self-Reported Pain After Exercise.

    Science.gov (United States)

    Custer, Lisa; Peer, Kimberly S; Miller, Lauren

    2017-05-01

    Muscle fatigue and acute muscle soreness occur after exercise. Application of a local vibration intervention may reduce the consequences of fatigue and soreness. To examine the effects of a local vibration intervention after a bout of exercise on balance, power, and self-reported pain. Single-blind crossover study. Laboratory. 19 healthy, moderately active subjects. After a 30-min bout of full-body exercise, subjects received either an active or a sham vibration intervention. The active vibration intervention was performed bilaterally over the muscle bellies of the triceps surae, quadriceps, hamstrings, and gluteals. At least 1 wk later, subjects repeated the bout, receiving the other vibration intervention. Static balance, dynamic balance, power, and self-reported pain were measured at baseline, after the vibration intervention, and 24 h postexercise. After the bout of exercise, subjects had reduced static and dynamic balance and increased self-reported pain regardless of vibration intervention. There were no differences between outcome measures between the active and sham vibration conditions. The local vibration intervention did not affect balance, power, or self-reported pain.

  12. The effect of amorphization on the local structure of arsenic chalcogenides

    International Nuclear Information System (INIS)

    Bordovsky, G. A.; Marchenko, A. V.; Seregin, P. P.; Terukov, E. I.

    2009-01-01

    The effect of amorphization on the symmetry of the local environment of chalcogen atoms in As 2 S 3 , As 2 Se 3 , and As 2 Te 3 compounds has been investigated by 129 Te( 129 I) Moessbauer spectroscopy. Three states of triply coordinated tellurium atoms are indistinguishable in the Moessbauer spectra of crystalline As 2 Te 3 . Amorphization of As 2 Te 3 decreases the local symmetry of triply coordinated states of Te atoms and leads to the formation of doubly coordinated states in -As-Te-Te-As- chains. In the structure of crystalline As 2 S 3 and As 2 Se 3 , two states of doubly coordinated chalcogen atoms X in -As-X-As- chains manifest themselves in the broadening of the Moessbauer spectra. Amorphization of As 2 S 3 and As 2 Se 3 is not accompanied by a change in the local symmetry of doubly coordinated chalcogen atoms in -As-X-As- chains; however, doubly coordinated states of S and Se atoms in -As-X-X-As chains are formed in the amorphous material.

  13. Effect of oxygen deficiency on electronic properties and local structure of amorphous tantalum oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Denny, Yus Rama [Department of Physics Education, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Firmansyah, Teguh [Department of Electrical Engineering, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Oh, Suhk Kun [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Kang, Hee Jae, E-mail: hjkang@cbu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Yang, Dong-Seok [Department of Physics Education, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Heo, Sung; Chung, JaeGwan; Lee, Jae Cheol [Analytical Engineering Center, Samsung Advanced Institute of Technology, Suwon 16678 (Korea, Republic of)

    2016-10-15

    Highlights: • The effect of oxygen flow rate on electronic properties and local structure of tantalum oxide thin films was studied. • The oxygen deficiency induced the nonstoichiometric state a-TaOx. • A small peak at 1.97 eV above the valence band side appeared on nonstoichiometric Ta{sub 2}O{sub 5} thin films. • The oxygen flow rate can change the local electronic structure of tantalum oxide thin films. - Abstract: The dependence of electronic properties and local structure of tantalum oxide thin film on oxygen deficiency have been investigated by means of X-ray photoelectron spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and X-ray absorption spectroscopy (XAS). The XPS results showed that the oxygen flow rate change results in the appearance of features in the Ta 4f at the binding energies of 23.2 eV, 24.4 eV, 25.8, and 27.3 eV whose peaks are attributed to Ta{sup 1+}, Ta{sup 2+}, Ta{sup 3+}/Ta{sup 4+}, and Ta{sup 5+}, respectively. The presence of nonstoichiometric state from tantalum oxide (TaOx) thin films could be generated by the oxygen vacancies. In addition, XAS spectra manifested both the increase of coordination number of the first Ta-O shell and a considerable reduction of the Ta-O bond distance with the decrease of oxygen deficiency.

  14. Effect of immunomodifier on radiation-induced antitumor immunity following local irradiation to tumor, 2

    International Nuclear Information System (INIS)

    Mukae, Shiro; Norimura, Toshiyuki; Tsuchiya, Takehiko

    1988-01-01

    This study was carried out to clarify whether or not the antitumor cell-mediated immunity of host is more effectively induced by the combined use of mouse interferon-α/β (MuIFN-α/β) with local irradiation than by simple local irradiation to tumor. C3H/He female mice, MM46 tumor cells and mouse interferon-α/β (MuIFN-α/β) were used in the experiment. Antitumor activity in mice was evaluated by the inhibition of tumor growth and mean survival days after treatment. Spleen cell killing activity to MM46 tumor cells was measured to evaluate the antitumor activity in vitro. In the case of single use of MuIFN-α/β, tumor growth was more rapid than in the non-treated group (control) in vivo. The mean survival days were also reduced. There was no siginificant difference in tumor growth inhibition between combined therapy using X-irradiation and MuIFN-α/β, and single therapy by local irradiation. However, in the case of administration of MuIFN-α/β after irradiation, the mean survival days was significantly increased compared with the group receiving X-ray irradiation only. (author)

  15. The effect of interacting dark energy on local measurements of the Hubble constant

    International Nuclear Information System (INIS)

    Odderskov, Io; Baldi, Marco; Amendola, Luca

    2016-01-01

    In the current state of cosmology, where cosmological parameters are being measured to percent accuracy, it is essential to understand all sources of error to high precision. In this paper we present the results of a study of the local variations in the Hubble constant measured at the distance scale of the Coma Cluster, and test the validity of correcting for the peculiar velocities predicted by gravitational instability theory. The study is based on N-body simulations, and includes models featuring a coupling between dark energy and dark matter, as well as two ΛCDM simulations with different values of σ 8 . It is found that the variance in the local flows is significantly larger in the coupled models, which increases the uncertainty in the local measurements of the Hubble constant in these scenarios. By comparing the results from the different simulations, it is found that most of the effect is caused by the higher value of σ 8 in the coupled cosmologies, though this cannot account for all of the additional variance. Given the discrepancy between different estimates of the Hubble constant in the universe today, cosmological models causing a greater cosmic variance is something that we should be aware of.

  16. Complementary effect of natural and sexual selection against immigrants maintains differentiation between locally adapted fish

    Science.gov (United States)

    Plath, Martin; Riesch, Rüdiger; Oranth, Alexandra; Dzienko, Justina; Karau, Nora; Schießl, Angela; Stadler, Stefan; Wigh, Adriana; Zimmer, Claudia; Arias-Rodriguez, Lenin; Schlupp, Ingo; Tobler, Michael

    2010-08-01

    Adaptation to ecologically heterogeneous environments can drive speciation. But what mechanisms maintain reproductive isolation among locally adapted populations? Using poeciliid fishes in a system with naturally occurring toxic hydrogen sulfide, we show that (a) fish from non-sulfidic sites ( Poecilia mexicana) show high mortality (95 %) after 24 h when exposed to the toxicant, while locally adapted fish from sulfidic sites ( Poecilia sulphuraria) experience low mortality (13 %) when transferred to non-sulfidic water. (b) Mate choice tests revealed that P. mexicana females exhibit a preference for conspecific males in non-sulfidic water, but not in sulfidic water, whereas P. sulphuraria females never showed a preference. Increased costs of mate choice in sulfidic, hypoxic water, and the lack of selection for reinforcement due to the low survival of P. mexicana may explain the absence of a preference in P. sulphuraria females. Taken together, our study may be the first to demonstrate independent—but complementary—effects of natural and sexual selection against immigrants maintaining differentiation between locally adapted fish populations.

  17. The effect of interacting dark energy on local measurements of the Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Odderskov, Io [Department of Physics and Astronomy, University of Aarhus, Ny Munkegade 120, Aarhus C (Denmark); Baldi, Marco [Dipartimento di Fisica e Astronomia, Alma Mater Studiorum Università di Bologna, viale Berti Pichat 6/2, I-40127, Bologna (Italy); Amendola, Luca, E-mail: isho07@phys.au.dk, E-mail: marco.baldi5@unibo.it, E-mail: l.amendola@thphys.uni-heidelberg.de [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)

    2016-05-01

    In the current state of cosmology, where cosmological parameters are being measured to percent accuracy, it is essential to understand all sources of error to high precision. In this paper we present the results of a study of the local variations in the Hubble constant measured at the distance scale of the Coma Cluster, and test the validity of correcting for the peculiar velocities predicted by gravitational instability theory. The study is based on N-body simulations, and includes models featuring a coupling between dark energy and dark matter, as well as two ΛCDM simulations with different values of σ{sub 8}. It is found that the variance in the local flows is significantly larger in the coupled models, which increases the uncertainty in the local measurements of the Hubble constant in these scenarios. By comparing the results from the different simulations, it is found that most of the effect is caused by the higher value of σ{sub 8} in the coupled cosmologies, though this cannot account for all of the additional variance. Given the discrepancy between different estimates of the Hubble constant in the universe today, cosmological models causing a greater cosmic variance is something that we should be aware of.

  18. Effects of opioids on local anesthesia in the rat: a codeine and tramadol study

    Directory of Open Access Journals (Sweden)

    Talita Girio Carnaval

    2013-12-01

    Full Text Available Opioids are central analgesics that act on the CNS (central nervous system and PNS (peripheral nervous system. We investigated the effects of codeine (COD and tramadol (TRAM on local anesthesia of the sciatic nerve. Eighty Wistar male rats received the following SC injections in the popliteal fossa: local anesthetic with epinephrine (LA; local anesthetic without vasoconstrictor (LA WV; COD; TRAM; LA + COD; LA + TRAM; COD 20 minutes prior to LA (COD 20' + LA or TRAM 20 minutes prior to LA (TRAM 20' + LA. As a nociceptive function, the blockade was considered the absence of a paw withdraw reflex. As a motor function, it was the absence of claudication. As a proprioceptive function, it was the absence of hopping and tactile responses. All data were compared using repeated-measures analysis of variance (ANOVA. Opioids showed a significant increase in the level of anesthesia, and the blockade duration of LA + COD was greater than that of the remaining groups (p < 0.05. The associated use of opioids improved anesthesia efficacy. This could lead to a new perspective in controlling dental pain.

  19. Locally advanced oral cavity squamous cell carcinoma: Barriers related to effective treatment

    Directory of Open Access Journals (Sweden)

    K C Lakshmaiah

    2015-01-01

    Full Text Available Background: Oral cavity cancer is a significant health problem in India. Majority of patients present with locally advanced disease requiring multimodality treatment. Compliance to recommended treatment is an important factor affecting outcome. Aims: The aim was to evaluate the outcome of locally advanced oral cavity cancer patients with regards to treatment adherence and to assess reasons of noncompliance. Materials and Methods: This was a prospective observational study. We included patients referred to Department of Medical Oncology for induction chemotherapy in view of locally advanced oral cavity cancer. Results: Only 15 (26% patients completed planned treatment schedule. Their 1 year overall survival was 93%. The remaining 43 patients who received inadequate treatment had a dismal 21% 1 year overall survival. Illiteracy, poverty, long waiting list for surgery, prolonged delay for health scheme treatment plan approval and dissatisfaction with attitude of hospital staffs are major barriers related to effective treatment of these patients. Conclusions: A detailed discussion with patient and their relatives regarding recommended treatment, proper implementation of health schemes, increasing trained manpower to avoid long waiting list for surgery, provision of additional financial support for family member accompanying the patient and a sympathetic approach toward patients are needed to help these patients overcome the battle.

  20. Baculite 3D Modeling: a New Method for Computing Buoyancy, Stability, and Orientation with Implications for Ectocochleate Cephalopod Hydrostatics

    Science.gov (United States)

    Peterman, D. J.; Barton, C. C.

    2017-12-01

    Ectocochleate (external) cephalopod shells are comprised of a body chamber which houses the organism's soft parts and the phragmocone which consists of a series of progressively larger chambers (camerae) divided by septa. The phragmocone is used as a passive gas float for buoyancy regulation. The soft body and the mineralized shell are denser than water and are negatively buoyant while the phragmocone is positively buoyant due to some fraction of gas in its chambers. This provides a neutrally buoyant condition when the total mass of the organism is equal to the mass of the displaced water. The static orientation of the organism occurs when the centers of buoyancy and mass are vertically aligned and stability is determined by their degree of separation. Three-dimensional modeling of a specimen of Baculites compressus (which has a straight conical shell) was performed using Autodesk Meshmixer, Netfabb ®, Blender 2.78, and MeshLab. The initial 3D mesh shapefile was created by Autodesk ReCap 360™ photogrammetry software. The specimen requirements for the models include: an external shell (ideally complete, otherwise approximated), a septum showing lower order frilling, and a suture pattern to reconstruct the higher order septal frilling (for complex septa). Volumes and centers of mass/buoyancy were calculated with MeshLab in order to determine neutrality, stability, and orientation. Our method can be used to investigate the influence of morphological features on these hydrostatic properties of ectocochleate cephalopods and also the paleoecological implications of different morphotypes. Baculites compressus, is found to assume relatively stable vertical orientations when the shell is positively or neutrally buoyant. By arbitrarily flooding all chambers, the ammonite becomes negatively buoyant, and the centers of buoyancy and mass virtually coincide. This reduces stability but allows the living ammonite to assume a larger range of orientations, including horizontal