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Sample records for oldroyd-b fluid induced

  1. MHD Flow of an Oldroyd-B Fluid through a Porous Space Induced by Sawtooth Pulses

    Institute of Scientific and Technical Information of China (English)

    Masood Khan; Zeeshan

    2011-01-01

    @@ We investigate the unsteady magnetohydrodynamic (MHD) flow of an Oldroyd-B fluid through a porous space inducedby sawtooth pulses.The fluid is assumed to be electrically conducting in the presence of a transverse uniform magnetic field.The porous space is taken into account using modified Darcy's law for the Oldroyd-B fluid.Exact solutions of the governing problem are obtained by using the Laplace transform method.The effects of the magnetic parameter, the permeability of the porous space and the elasticity parameter of the fluid are studied on the flow characteristics.

  2. Fractional magnetohydrodynamics Oldroyd-B fluid over an oscillating plate

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    Jamil Muhammad

    2013-01-01

    Full Text Available This paper presents some new exact solutions corresponding to the oscillating flows of a MHD Oldroyd-B fluid with fractional derivatives. The fractional calculus approach in the governing equations is used. The exact solutions for the oscillating motions of a fractional MHD Oldroyd-B fluid due to sine and cosine oscillations of an infinite plate are established with the help of discrete Laplace transform. The expressions for velocity field and the associated shear stress that have been obtained, presented in series form in terms of Fox H functions, satisfy all imposed initial and boundary conditions. Similar solutions for ordinary MHD Oldroyd-B, fractional and ordinary MHD Maxwell, fractional and ordinary MHD Second grade and MHD Newtonian fluid as well as those for hydrodynamic fluids are obtained as special cases of general solutions. Finally, the obtained solutions are graphically analyzed through various parameters of interest.

  3. Stokes' first problem for a viscoelastic fluid with the generalized Oldroyd-B model

    Institute of Scientific and Technical Information of China (English)

    Haitao Qi; Mingyu Xu

    2007-01-01

    The flow near a wall suddenly set in motion for a viscoelastic fluid with the generalized Oldroyd-B model is studied. The fractional calculus approach is used in the constitutive relationship of fluid model. Exact analytical solutions of velocity and stress are obtained by using the discrete Laplace transform of the sequential fractional derivative and the Fox H-function. The obtained results indicate that some well known solutions for the Newtonian fluid, the generalized second grade fluid as well as the ordinary Oldroyd-B fluid, as limiting cases, are included in our solutions.

  4. New Exact Solutions for an Oldroyd-B Fluid in a Porous Medium

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    I. Khan

    2011-01-01

    Full Text Available New exact solutions for unsteady magnetohydrodynamic (MHD flows of an Oldroyd-B fluid have been derived. The Oldroyd-B fluid saturates the porous space. Two different flow cases have been considered. The analytical expressions for velocity and shear stress fields have been obtained by using Laplace transform technique. The corresponding solutions for hydrodynamic Oldroyd-B fluid in a nonporous space appeared as the limiting cases of the obtained solutions. Similar solutions for MHD Newtonian fluid passing through a porous space are also recovered. Graphs are sketched for the pertinent parameters. It is found that the MHD and porosity parameters have strong influence on velocity and shear stress fields.

  5. Analytic solutions of Oldroyd-B fluid with fractional derivatives in a circular duct that applies a constant couple

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    M.B. Riaz

    2016-12-01

    Full Text Available The aim of this article was to analyze the rotational flow of an Oldroyd-B fluid with fractional derivatives, induced by an infinite circular cylinder that applies a constant couple to the fluid. Such kind of problem in the settings of fractional derivatives has not been found in the literature. The solutions are based on an important remark regarding the governing equation for the non-trivial shear stress. The solutions that have been obtained satisfy all imposed initial and boundary conditions and can easily be reduced to the similar solutions corresponding to ordinary Oldroyd-B, fractional/ordinary Maxwell, fractional/ordinary second-grade, and Newtonian fluids performing the same motion. The obtained results are expressed in terms of Newtonian and non-Newtonian contributions. Finally, the influence of fractional parameters on the velocity, shear stress and a comparison between generalized and ordinary fluids is graphically underlined.

  6. The Rayleigh-Stokes problem for an edge in a generalized Oldroyd-B fluid

    Science.gov (United States)

    Fetecau, Corina; Jamil, Muhammad; Fetecau, Constantin; Vieru, Dumitru

    2009-09-01

    The velocity field corresponding to the Rayleigh-Stokes problem for an edge, in an incompressible generalized Oldroyd-B fluid has been established by means of the double Fourier sine and Laplace transforms. The fractional calculus approach is used in the constitutive relationship of the fluid model. The obtained solution, written in terms of the generalized G-functions, is presented as a sum of the Newtonian solution and the corresponding non-Newtonian contribution. The solution for generalized Maxwell fluids, as well as those for ordinary Maxwell and Oldroyd-B fluids, performing the same motion, is obtained as a limiting case of the present solution. This solution can be also specialized to give the similar solution for generalized second grade fluids. However, for simplicity, a new and simpler exact solution is established for these fluids. For β → 1, this last solution reduces to a previous solution obtained by a different technique.

  7. Failure of energy stability in Oldroyd-B fluids at arbitrarily low Reynolds numbers

    CERN Document Server

    Döring, C; Schumacher, J

    2004-01-01

    Energy theory for incompressible Newtonian fluids is, in many cases, capable of producing strong absolute stability criteria for steady flows. In those fluids the kinetic energy naturally defines a norm in which perturbations decay monotonically in time at sufficiently low (but non-zero) Reynolds numbers. There are, however, at least two obstructions to the generalization of such methods to Oldroyd-B fluids. One previously recognized problem is the fact that the natural energy does not correspond to a proper functional norm on perturbations. Another problem, original to this work, is the fact that fluctuations in Oldroyd-B fluids may be subject to non-normal amplification at arbitrarily low Reynolds numbers (albeit at sufficiently large Weissenberg numbers). Such transient growth, occuring even when the base flow is linearly stable, precludes the uniform monotonic decay of any reasonable measure of the disturbance's amplitude.

  8. Dynamics of two balls in bounded shear flow of Oldroyd-B fluids

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    Chiu, Shang-Huan; Pan, Tsorng-Whay; Glowinski, Roland

    2016-11-01

    The motion of dilute sphere suspensions in bounded shear flow of Oldroyd-B fluids has been studied at zero Reynolds number. Up to the initial sphere displacement, binary encounters of spheres in bounded shear flow of Newtonian fluid are known to have either swapping or non-swapping trajectories at zero Reynolds number. We have simulated the interaction of two spherical particles in Newtonian fluid and Oldroyd-B fluid, respectively, and compared the resulting motions of particles. The motions of two spheres in Newtonian fluid are consistent with those in literature. In Oldroyd-B fluid, swapping trajectories can be obtained for the lower values of the relaxation time. For the non-swapping cases, two spheres do not return to their original transversed position once the encounter terminates, but being closer to the mid-plane between two walls, due to the effect of the elastic force. Two spheres may also attract each other first and then form rotating dipole in bounded shear flow, depending on the value of the relaxation time and initial sphere displacement. NSF.

  9. FLOW AND HEAT TRANSFER OF OLDROYD-B FLUIDS IN A ROTATING CURVED PIPE

    Institute of Scientific and Technical Information of China (English)

    SHEN Xin-rong; ZHANG Ming-kan; MA Jian-feng; ZHANG Ben-zhao

    2008-01-01

    The flow and convected heat transfer of the Oldroyd-B fluids in a rotating curved pipe with circular cross-section were investigated by employing a perturbation method. A perturbation solution up to the second order was obtained for a small curvature ratio, κ. The variations of axial velocity distribution and secondary flow structure with F, Re and We were discussed in detail in order to investigate the combined effects of the three parameters on flow structure. The combined effects of the Coriolis force, inertia force and elastic force on the temperature distribution were also analyzed, which are greater than the adding independent effects of the three forces. The variations of the flow rate and Nusselt number with the rotation, inertia and elasticity were examined as well. The results show the characteristics of the heat and mass transfer of the Oldroyd-B fluids in a rotating curved pipe.

  10. FLOW OF OLDROYD-B FLUID IN ROTATING CURVED SQUARE DUCTS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-kan; SHEN Xin-rong; MA Jian-feng; ZHANG Ben-zhao

    2007-01-01

    The fully developed Oldroyd-B fluid flow through rotating square ducts was numerically studied. The effects of the rotation on secondary flow, axial velocity, and axial normal stress were examined in detail. The results indicated that all of the secondary flow, the axial flow, and the axial normal stress were evidently affected by the rotation. The Taylor-Proudman phenomenon could be observed in the flow. For the secondary flow, the four vortices structure and the six vortices structure were described. Recent studies also showed the effects of rotation on the axial normal stress.

  11. Three-dimensional Oldroyd-B fluid flow with Cattaneo-Christov heat flux model

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    Shehzad, S. A.; Hayat, T.; Abbasi, F. M.; Javed, Tariq; Kutbi, M. A.

    2016-04-01

    The impact of Cattaneo-Christov heat flux in three-dimensional flow of an Oldroyd-B fluid over a bidirectional stretching surface is explored in this article. The boundary layer flow of an incompressible fluid is considered. Heat transfer analysis is discussed via the Cattaneo-Christov model of heat flux. Similarity transformations lead to the nonlinear ordinary differential systems. Convergent solutions of dimensionless velocities and temperature have been computed. Convergence analysis is presented graphically and numerically. The influence of physical parameters on the velocities and temperature are plotted and discussed. We observed that the values of temperature gradient are higher for the Cattaneo-Christov heat flux model when we compare it with the values obtained by the simple Fourier's law of heat conduction.

  12. On the stability of natural convection in a porous vertical slab saturated with an Oldroyd-B fluid

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    Shankar, B. M.; Shivakumara, I. S.

    2017-06-01

    The stability of the conduction regime of natural convection in a porous vertical slab saturated with an Oldroyd-B fluid has been studied. A modified Darcy's law is utilized to describe the flow in a porous medium. The eigenvalue problem is solved using Chebyshev collocation method and the critical Darcy-Rayleigh number with respect to the wave number is extracted for different values of physical parameters. Despite the basic state being the same for Newtonian and Oldroyd-B fluids, it is observed that the basic flow is unstable for viscoelastic fluids—a result of contrast compared to Newtonian as well as for power-law fluids. It is found that the viscoelasticity parameters exhibit both stabilizing and destabilizing influence on the system. Increase in the value of strain retardation parameter Λ _2 portrays stabilizing influence on the system while increasing stress relaxation parameter Λ _1 displays an opposite trend. Also, the effect of increasing ratio of heat capacities is to delay the onset of instability. The results for Maxwell fluid obtained as a particular case from the present study indicate that the system is more unstable compared to Oldroyd-B fluid.

  13. The viscoelastic effects on thermal convection of an Oldroyd-B fluid in open-top porous media

    Institute of Scientific and Technical Information of China (English)

    NIU Jun; SHI Zai-hong; TAN Wen-chang

    2013-01-01

    The effects of two viscoelastic parameters on the thermal convection of a viscoelastic Oldroyd-B fluid in an open-top porous square box with constant heat flux are investigated.The results show that the increase of relaxation time is able to destabilize the fluid flow leading to a higher heat transfer rate,while the increase of retardation time tends to stabilize the flow and suppress the heat transfer.The flow bifurcation appears earlier with the increase of the relaxation time and the decrease of the retardation time,resulting in more complicated flow patterns in the porous medium.

  14. Flow of an Oldroyd-B Fluid past an Unsteady Bidirectional Stretching Sheet with Constant Temperature and Constant Heat Flux

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    Manzoor Ahmad

    2016-01-01

    Full Text Available This article describes the time dependent flow of a non-Newtonian fluid with heat transfer. We consider three dimensional unsteady flow and heat transfer of an Oldroyd-B fluid for constant temperature (CT and constant heat flux (CH cases over an unsteady bidirectional stretching surface. Homotopic solutions of the governing boundary value problems have been computed. Convergence for both velocity and temperature profiles is explored. The effects of emerging parameters on the velocity and temperature fields are investigated with the help of graphs and tabular data. It is observed that due to unsteadiness temperature in both the constant temperature and constant heat flux cases decrease significantly. Comparison of obtained and previously published results is found in excellent agreement.

  15. A mathematical model for mixed convective flow of chemically reactive Oldroyd-B fluid between isothermal stretching disks

    Science.gov (United States)

    Hashmi, M. S.; Khan, N.; Ullah Khan, Sami; Rashidi, M. M.

    In this study, we have constructed a mathematical model to investigate the heat source/sink effects in mixed convection axisymmetric flow of an incompressible, electrically conducting Oldroyd-B fluid between two infinite isothermal stretching disks. The effects of viscous dissipation and Joule heating are also considered in the heat equation. The governing partial differential equations are converted into ordinary differential equations by using appropriate similarity variables. The series solution of these dimensionless equations is constructed by using homotopy analysis method. The convergence of the obtained solution is carefully examined. The effects of various involved parameters on pressure, velocity and temperature profiles are comprehensively studied. A graphical analysis has been presented for various values of problem parameters. The numerical values of wall shear stress and Nusselt number are computed at both upper and lower disks. Moreover, a graphical and tabular explanation for critical values of Frank-Kamenetskii regarding other flow parameters.

  16. Comment on "The velocity field due to an oscillating plate in an Oldroyd-B fluid" by C.C. Hopkins and J.R. de Bruyn [Can. J. Phys. 92, 533 (2014)

    CERN Document Server

    Christov, Ivan C

    2015-01-01

    We correct certain errors and ambiguities in the recent pedagogical article by Hopkins and de Bruyn. The early-time asymptotics of the solution to the transient version of Stokes' second problem for an Oldroyd-B fluid in a half-space is presented, as an Appendix, to complement the late-time asymptotics given by Hopkins and de Bruyn.

  17. Three-dimensional flow of an Oldroyd-B fluid over a bidirectional stretching surface with prescribed surface temperature and prescribed surface heat flux

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    Hayat Tasawar

    2014-06-01

    Full Text Available This paper concentrates on the mathematical modelling for three-dimensional flow of an incompressible Oldroyd- B fluid over a bidirectional stretching surface. Mathematical formulation incorporates the effect of internal heat source/sink. Two cases of heat transfer namely the prescribed surface temperature (PST and prescribed surface heat flux (PHF are considered. Computations for the governing nonlinear flow are presented using homotopy analysis method. Comparison of the present analysis is shown with the previous limiting result. The obtained results are discussed by plots of interesting parameters for both PST and PHF cases. We examine that an increase in Prandtl number leads to a reduction in PST and PHF. It is noted that both PST and PHF are increased with an increase in source parameter. Further we have seen that the temperature is an increasing function of ratio parameter

  18. Vortex behavior of the Oldroyd-B fluid in the 4-1 planar contraction simulated with the streamfunction–log-conformation formulation

    DEFF Research Database (Denmark)

    Comminal, Raphael Benjamin; Hattel, Jesper Henri; Alves, Manuel A.

    2016-01-01

    In this paper, we present numerical solutions of the Oldroyd-B fluid flowing through a 4:1 planar contraction, for Weissenberg numbers (Wi) up to 20. The incompressible viscoelastic flows are simulated with the streamfunction–log-conformation methodology. The log-conformation representation...... guarantees by construction the positive-definiteness of the conformation tensor, which circumvents the appearance of the high Weissenberg number problem. In addition, the streamfunction flow formulation removes the pressure variable from the governing equations and automatically satisfies the mass...... of the recirculation vortices produced at the contraction plane are in excellent agreement with the benchmark solutions, available in the literature for Weissenberg numbers up to 3. For highly elastic flows, our results agree qualitatively well with the data of Afonso et al. (2011) [53]. Our simulations predict...

  19. Dynamics of two disks settling in a two-dimensional narrow channel: From periodic motion to vertical chain in Oldroyd-B fluid

    CERN Document Server

    Pan, Tsorng-Whay

    2016-01-01

    In this article we present a numerical study of the dynamics of two disks settling in a narrow vertical channel filled with Oldroyd-B fluid. Two kinds of particle dynamics are obtained: (i) periodic interaction between two disks and (ii) the chain formation of two disks. For the periodic interaction of two disks, two different motions are obtained: (a) two disks stay far apart and interact periodically and (b) two disks interact closely and then far apart in a periodic way, like the drafting, kissing and tumbling of two disks sedimenting in Newtonian fluid, due to the lack of strong enough elastic force. For the formation of two disk chain occurred at higher values of the elasticity number, it is either a tilted chain or a vertical chain. The tilted chain can be obtained for either that the elasticity number is less than the critical value for having the vertical chain or that the Mach number is greater than the critical value for a long body to fall broadside-on. Hence the values of the elasticity number and...

  20. Global Existence of Classical Solutions for Some Oldroyd-B Model via the Incompressible Limit

    Institute of Scientific and Technical Information of China (English)

    Zhen LEI

    2006-01-01

    In this paper, we prove local and global existence of classical solutions for a system of equations concerning an incompressible viscoelastic fluid of Oldroyd-B type via the incompressible limit when the initial data are sufficiently small.

  1. The Effect of Thermophoresis on Unsteady Oldroyd-B Nanofluid Flow over Stretching Surface.

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    Faiz G Awad

    Full Text Available There are currently only a few theoretical studies on convective heat transfer in polymer nanocomposites. In this paper, the unsteady incompressible flow of a polymer nanocomposite represented by an Oldroyd-B nanofluid along a stretching sheet is investigated. Recent studies have assumed that the nanoparticle fraction can be actively controlled on the boundary, similar to the temperature. However, in practice, such control presents significant challenges and in this study the nanoparticle flux at the boundary surface is assumed to be zero. We have used a relatively novel numerical scheme; the spectral relaxation method to solve the momentum, heat and mass transport equations. The accuracy of the solutions has been determined by benchmarking the results against the quasilinearisation method. We have conducted a parametric study to determine the influence of the fluid parameters on the heat and mass transfer coefficients.

  2. The Effect of Thermophoresis on Unsteady Oldroyd-B Nanofluid Flow over Stretching Surface.

    Science.gov (United States)

    Awad, Faiz G; Ahamed, Sami M S; Sibanda, Precious; Khumalo, Melusi

    2015-01-01

    There are currently only a few theoretical studies on convective heat transfer in polymer nanocomposites. In this paper, the unsteady incompressible flow of a polymer nanocomposite represented by an Oldroyd-B nanofluid along a stretching sheet is investigated. Recent studies have assumed that the nanoparticle fraction can be actively controlled on the boundary, similar to the temperature. However, in practice, such control presents significant challenges and in this study the nanoparticle flux at the boundary surface is assumed to be zero. We have used a relatively novel numerical scheme; the spectral relaxation method to solve the momentum, heat and mass transport equations. The accuracy of the solutions has been determined by benchmarking the results against the quasilinearisation method. We have conducted a parametric study to determine the influence of the fluid parameters on the heat and mass transfer coefficients.

  3. Numerical study of boundary layer flow and heat transfer of oldroyd-B nanofluid towards a stretching sheet.

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    Sohail Nadeem

    Full Text Available In the present article, we considered two-dimensional steady incompressible Oldroyd-B nanofluid flow past a stretching sheet. Using appropriate similarity variables, the partial differential equations are transformed to ordinary (similarity equations, which are then solved numerically. The effects of various parameters, namely, Deborah numbers [Formula: see text] and [Formula: see text], Prandtl parameter [Formula: see text], Brownian motion [Formula: see text], thermophoresis parameter [Formula: see text] and Lewis number [Formula: see text], on flow and heat transfer are investigated. To see the validity of the present results, we have made the comparison of present results with the existing literature.

  4. Nonlinear convective analysis of a rotating Oldroyd-B nanofluid layer under thermal non-equilibrium utilizing Al2O3-EG colloidal suspension

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    Agarwal, Shilpi; Rana, Puneet

    2016-04-01

    In this paper, we examine a layer of Oldroyd-B nanofluid for linear and nonlinear regimes under local thermal non-equilibrium conditions for the classical Rayleigh-Bénard problem. The free-free boundary condition has been implemented with the flux for nanoparticle concentration being zero at edges. The Oberbeck-Boussinesq approximation holds good and for the rotational effect Coriolis term is included in the momentum equation. A two-temperature model explains the effect of local thermal non-equilibrium among the particle and fluid phases. The criteria for onset of stationary convection has been derived as a function of the non-dimensionalized parameters involved including the Taylor number. The assumed boundary conditions negate the possibility of overstability due to the absence of opposing forces responsible for it. The thermal Nusselt number has been obtained utilizing a weak nonlinear theory in terms of various pertinent parameters in the steady and transient mode, and has been depicted graphically. The main findings signify that the rotation has a stabilizing effect on the system. The stress relaxation parameter λ_1 inhibits whereas the strain retardation parameter λ_2 exhibits heat transfer utilizing Al2O3 nanofluids.

  5. Linear stability of plane creeping Couette flow for Burgers fluid

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    Hu, Kai-Xin; Peng, Jie; Zhu, Ke-Qin

    2013-02-01

    It is well known that plane creeping Couette flow of UCM and Oldroy-B fluids are linearly stable. However, for Burges fluid, which includes UCM and Oldroyd-B fluids as special cases, unstable modes are detected in the present work. The wave speed, critical parameters and perturbation mode are studied for neutral waves. Energy analysis shows that the sustaining of perturbation energy in Poiseuille flow and Couette flow is completely different. At low Reynolds number limit, analytical solutions are obtained for simplified perturbation equations. The essential difference between Burgers fluid and Oldroyd-B fluid is revealed to be the fact that neutral mode exists only in the former.

  6. The role of body flexibility in stroke enhancements for finite-length undulatory swimmers in viscoelastic fluids

    CERN Document Server

    Thomases, Becca

    2016-01-01

    The role of passive body dynamics on the kinematics of swimming micro-organisms in complex fluids is investigated. Asymptotic analysis of small amplitude motions of a finite-length undulatory swimmer in a Stokes-Oldroyd-B fluid is used to predict shape changes that result as body elasticity and fluid elasticity are varied. Results from the analysis are compared with numerical simulations, and the small amplitude analysis of shape changes is quantitatively accurate at both small and large amplitudes, even for strongly elastic flows. We compute a stroke-induced swimming speed that accounts for the shape changes, but not additional effects of fluid elasticity. Elastic induced shape changes lead to larger amplitude strokes for sufficiently soft swimmers in a viscoelastic fluid, and these stroke boosts can lead to swimming speed-ups, but we find that additional effects of fluid elasticity generically slow down swimmers. High amplitude strokes in strongly elastic flows lead to a qualitatively different regime in wh...

  7. Exact solutions for the flow of non-Newtonian fluid with fractional derivative in an annular pipe

    Science.gov (United States)

    Tong, Dengke; Wang, Ruihe; Yang, Heshan

    2005-08-01

    This paper deals with some unsteady unidirectional transient flows of Oldroyd-B fluid in an annular pipe. The fractional calculus approach in the constitutive relationship model Oldroyd-B fluid is introduced and a generalized Jeffreys model with the fractional calculus has been built. Exact solutions of some unsteady flows of Oldroyd-B fluid in an annular pipe are obtained by using Hankel transform and Laplace transform for fractional calculus. The following four problems have been studied: (1) Poiseuille flow due to a constant pressure gradient; (2) axial Couette flow in an annulus; (3) axial Couette flow in an annulus due to a longitudinal constant shear; (4) Poiseuille flow due to a constant pressure gradient and a longitudinal constant shear. The well-known solutions for Navier-Stokes fluid, as well as those corresponding to a Maxwell fluid and a second grade one, appear as limited cases of our solutions.

  8. Exact solutions for the flow of non-Newtonian fluid with fractional derivative in an annular pipe

    Institute of Scientific and Technical Information of China (English)

    TONG Dengke; WANG Ruihe; YANG Heshan

    2005-01-01

    This paper deals with some unsteady unidirectional transient flows of Oldroyd-B fluid in an annular pipe. The fractional calculus approach in the constitutive relationship model Oldroyd-B fluid is introduced and a generalized Jeffreys model with the fractional calculus has been built. Exact solutions of some unsteady flows of Oldroyd-B fluid in an annular pipe are obtained by using Hankel transform and Laplace transform for fractional calculus. The following four problems have been studied: (1) Poiseuille flow due to a constant pressure gradient; (2) axial Couette flow in an annulus; (3) axial Couette flow in an annulus due to a longitudinal constant shear; (4) Poiseuille flow due to a constant pressure gradient and a longitudinal constant shear. The well-known solutions for Navier-Stokes fluid, as well as those corresponding to a Maxwell fluid and a second grade one, appear as limited cases of our solutions.

  9. Numerical Simulation of Planar 4:1 Contraction Flow of a Viscoelastic Fluid Using a Higher-order Upwind Finite Volume Method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    New form of the constitutive equations for the Oldroyd-B model, which have physical meaning, is developed to facilitate theoretical analysis. The new equations are used to simulate planar 4∶1 contraction flow of a Maxwell fluid using a third-order upwind finite volume method. The numerical results compare well with the theoretical solutions and the results of other references to show the effectiveness of the numerical method. Numerical experiments suggest that the present method not only converges fairly rapidly, but can also generate a highly resolved approximation to an Oldroyd-B fluid flow at a high Weissenberg number.

  10. Linear stability of plane creeping Couette flow for Burgers fluid

    Institute of Scientific and Technical Information of China (English)

    Kai-Xin Hu; Jie Peng; Ke-Qin Zhu

    2013-01-01

    It is well known that plane creeping Couette flow of UCM and Oldroy-B fluids are linearly stable.However,for Burges fluid,which includes UCM and Oldroyd-B fluids as special cases,unstable modes are detected in the present work.The wave speed,critical parameters and perturbation mode are studied for neutral waves.Energy analysis shows that the sustaining of perturbation energy in Poiseuille flow and Couette flow is completely different.At low Reynolds number limit,analytical solutions are obtained for simplified perturbation equations.The essential difference between Burgers fluid and Oldroyd-B fluid is revealed to be the fact that neutral mode exists only in the former.

  11. Comments on: "Energetic balance for the Rayleigh--Stokes problem of an Oldroyd-B fluid" [Nonlinear Anal. RWA 12 (2011) 1

    CERN Document Server

    Christov, Ivan C

    2011-01-01

    We point out that an erroneous derivation in the recent paper [Fetecau et al., Nonlinear Anal. RWA 12 (2011) 1] yields a correct solution by accident. Additionally, a number of misrepresentations and inaccuracies in the latter recent paper are identified, corrected and/or clarified in this Comment. Finally, a listing of recent papers in this journal that make a mistake applying the Fourier sine transform, and thus present erroneous solutions, is given as an Appendix.

  12. First general solutions for unidirectional motions of rate type fluids over an infinite plate

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    Constantin Fetecau

    2015-09-01

    Full Text Available Based on a simple but important remark regarding the governing equation for the non-trivial shear stress corresponding to the motion of a fluid over an infinite plate, exact solutions are established for the motion of Oldroyd-B fluids due to the plate that applies an arbitrary time-dependent shear stress to the fluid. These solutions, that allow us to provide the first exact solutions for motions of rate type fluids produced by an infinite plate that applies constant, constantly accelerating or oscillating shears stresses to the fluid, can easily be reduced to the similar solutions for Maxwell, second grade or Newtonian fluids performing the same motion. Furthermore, the obtained solutions are used to develop general solutions for the motion induced by a moving plate and to correct or recover as special cases different known results from the existing literature. Consequently, the motion problem of such fluids over an infinite plate that is moving in its plane or applies a shear stress to the fluid is completely solved.

  13. Convective heat transfer for viscoelastic fluid in a curved pipe

    Energy Technology Data Exchange (ETDEWEB)

    Norouzi, M.; Kayhani, M.H. [Shahrood University of Technology, Mechanical Engineering Department, Shahrood (Iran); Nobari, M.R.H. [Amirkabir University of Technology, Mechanical Engineering Department, Tehran (Iran); Joneidi, A.A. [Eindhoven University of Technology, Mechanical-Polymer Technology Group, Eindhoven (Netherlands)

    2010-10-15

    In this paper, fully developed convective heat transfer of viscoelastic flow in a curved pipe under the constant heat flux at the wall is investigated analytically using a perturbation method. Here, the curvature ratio is used as the perturbation parameter and the Oldroyd-B model is applied as the constitutive equation. In the previous studies, the Dirichlet boundary condition for the temperature at the wall has been used to simplify the solution, but here exactly the non-homogenous Neumann boundary condition is considered to solve the problem. Based on this solution, the non-axisymmetric temperature distribution of Dean flow is obtained analytically and the effect of flow parameters on the flow field is investigated in detail. The current analytical results indicate that increasing the Weissenberg number, viscosity ratio, curvature ratio, and Prandtl number lead to the increase of the heat transfer in the Oldroyd-B fluid flow. (orig.)

  14. Helical flows of fractionalized Burgers' fluids

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    Muhammad Jamil

    2012-03-01

    Full Text Available The unsteady flows of Burgers’ fluid with fractional derivatives model, through a circular cylinder, is studied by means of the Laplace and finite Hankel transforms. The motion is produced by the cylinder that at the initial moment begins to rotate around its axis with an angular velocity Ωt, and to slide along the same axis with linear velocity Ut. The solutions that have been obtained, presented in series form in terms of the generalized Ga,b,c(•, t functions, satisfy all imposed initial and boundary conditions. Moreover, the corresponding solutions for fractionalized Oldroyd-B, Maxwell and second grade fluids appear as special cases of the present results. Furthermore, the solutions for ordinary Burgers’, Oldroyd-B, Maxwell, second grade and Newtonian performing the same motion, are also obtained as special cases of general solutions by substituting fractional parameters α = β = 1. Finally, the influence of the pertinent parameters on the fluid motion, as well as a comparison among models, is shown by graphical illustrations.

  15. On the MHD flow of fractional generalized Burgers' fluid with modified Darcy's law

    Institute of Scientific and Technical Information of China (English)

    T. Hayat; M. Khan; S. Asghar

    2007-01-01

    This work is concerned with applying the fractional calculus approach to the magnetohydrodynamic(MHD) pipe flow of a fractional generalized Burgers' fluid in a porous space by using modified Darcy's relationship. The fluid is electrically conducting in the presence of a constant applied magnetic field in the transverse direction. Exact solution for the velocity distribution is developed with the help of Fourier transform for fractional calculus. The solutions for a Navier-Stokes, second grade, Maxwell, Oldroyd-B and Burgers' fluids appear as the limiting cases of the present analysis.

  16. Maximum magnitude earthquakes induced by fluid injection

    Science.gov (United States)

    McGarr, Arthur F.

    2014-01-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  17. Maximum magnitude earthquakes induced by fluid injection

    Science.gov (United States)

    McGarr, A.

    2014-02-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  18. Swimming speeds of filaments in nonlinearly viscoelastic fluids

    CERN Document Server

    Fu, Henry C; Powers, Thomas R; 10.1063/1.3086320

    2010-01-01

    Many microorganisms swim through gels and non-Newtonian fluids in their natural environments. In this paper, we focus on microorganisms which use flagella for propulsion. We address how swimming velocities are affected in nonlinearly viscoelastic fluids by examining the problem of an infinitely long cylinder with arbitrary beating motion in the Oldroyd-B fluid. We solve for the swimming velocity in the limit in which deflections of the cylinder from its straight configuration are small relative to the radius of the cylinder and the wavelength of the deflections; furthermore, the radius of the cylinder is small compared to the wavelength of deflections. We find that swimming velocities are diminished by nonlinear viscoelastic effects. We apply these results to examine what types of swimming motions can produce net translation in a nonlinear fluid, comparing to the Newtonian case, for which Purcell's "scallop" theorem describes how time-reversibility constrains which swimming motions are effective. We find that...

  19. Coping with earthquakes induced by fluid injection

    Science.gov (United States)

    McGarr, Arthur F.; Bekins, Barbara; Burkardt, Nina; Dewey, James W.; Earle, Paul S.; Ellsworth, William L.; Ge, Shemin; Hickman, Stephen H.; Holland, Austin F.; Majer, Ernest; Rubinstein, Justin L.; Sheehan, Anne

    2015-01-01

    Large areas of the United States long considered geologically stable with little or no detected seismicity have recently become seismically active. The increase in earthquake activity began in the mid-continent starting in 2001 (1) and has continued to rise. In 2014, the rate of occurrence of earthquakes with magnitudes (M) of 3 and greater in Oklahoma exceeded that in California (see the figure). This elevated activity includes larger earthquakes, several with M > 5, that have caused significant damage (2, 3). To a large extent, the increasing rate of earthquakes in the mid-continent is due to fluid-injection activities used in modern energy production (1, 4, 5). We explore potential avenues for mitigating effects of induced seismicity. Although the United States is our focus here, Canada, China, the UK, and others confront similar problems associated with oil and gas production, whereas quakes induced by geothermal activities affect Switzerland, Germany, and others.

  20. Temperature induced pore fluid pressurization in geomaterials

    CERN Document Server

    Ghabezloo, Siavash

    2010-01-01

    The theoretical basis of the thermal response of the fluid-saturated porous materials in undrained condition is presented. It has been demonstrated that the thermal pressurization phenomenon is controlled by the discrepancy between the thermal expansion of the pore fluid and of the solid phase, the stress-dependency of the compressibility and the non-elastic volume changes of the porous material. For evaluation of the undrained thermo-poro-elastic properties of saturated porous materials in conventional triaxial cells, it is important to take into account the effect of the dead volume of the drainage system. A simple correction method is presented to correct the measured pore pressure change and also the measured volumetric strain during an undrained heating test. It is shown that the porosity of the tested material, its drained compressibility and the ratio of the volume of the drainage system to the one of the tested sample, are the key parameters which influence the most the error induced on the measuremen...

  1. COMPLEX HEAT TRANSFER ENHANCEMENT BY FLUID INDUCED VIBRATION

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new method of heat transfer enhancement by fluid induced vibration was put forward, and its theoretical analysis and experimental study were performed. Though people always try to prophylaxis fluid induced vibration for regarding it as an accident, the utilization space of fluid induced vibration is still very large. The in-surface and out-surface vibrations which come from the fluid induce elastic tube bundles, can effectively increase the convective heat transfer coefficient, and also decrease the fouling resistance, then increase the heat transfer coefficient remarkably.

  2. Small-amplitude swimmers can self-propel faster in viscoelastic fluids

    CERN Document Server

    Riley, Emily E

    2015-01-01

    Many small organisms self-propel in viscous fluids using travelling wave-like deformation of their bodies or appendages. Examples include small nematodes moving through soil using whole-body undulations or spermatozoa swimming through mucus using flagellar waves. When self-propulsion occurs in a non-Newtonian fluid, one fundamental question is whether locomotion will occur faster or slower than in a Newtonian environment. Here we consider the general problem of swimming using small-amplitude periodic waves in a viscoelastic fluid described by the classical Oldroyd-B constitutive relationship. Using Taylor's swimming sheet model, we show that if all travelling waves move in the same direction, the locomotion speed of the organism is systematically decreased. However, if we allow waves to travel in two opposite directions, we show that this can lead to enhancement of the swimming speed, which is physically interpreted as due to asymmetric viscoelastic damping of waves with different frequencies. A change of the...

  3. Voltage-Induced Buckling of Dielectric Films using Fluid Electrodes

    CERN Document Server

    Tavakol, Behrouz

    2016-01-01

    Accurate and integrable control of different flows within microfluidic channels is crucial to further development of lab-on-a-chip and fully integrated adaptable structures. Here we introduce a flexible microactuator that buckles at a high deformation rate and alters the downstream fluid flow. The microactuator consists of a confined, thin, dielectric film that buckles into the microfluidic channel when exposed to voltage supplied through conductive fluid electrodes. We estimate the critical buckling voltage, and characterize the buckled shape of the actuator. Finally, we investigate the effects of frequency, flow rate, and the pressure differences on the behavior of the buckling structure and the resulting fluid flow. These results demonstrate that the voltage--induced buckling of embedded microstructures using fluid electrodes provides a means for high speed attenuation of microfluidic flow.

  4. The Thermodynamical Instability Induced by Pressure Ionization in Fluid Helium

    CERN Document Server

    Li, Qiong; Zhang, Gong-Mu; Zhao, Yan-Hong; Lu, Guo; Tian, Ming-Feng; Song, Hai-Feng

    2016-01-01

    A systematic study of pressure ionization is carried out in the chemical picture by the example of fluid helium. By comparing the variants of the chemical model, it is demonstrated that the behavior of pressure ionization depends on the construction of the free energy function. In the chemical model with the Coulomb free energy described by the Pad\\'e interpolation formula, thermodynamical instability induced by pressure ionization is found to be manifested by a discontinuous drop or a continuous fall and rise along the pressure-density curve as well as the pressure-temperature curve, which is very much like the first order liquid-liquid phase transition of fluid hydrogen from the first principles simulations. In contrast, in the variant chemical model with the Coulomb free energy term empirically weakened, no thermodynamical instability is induced when pressure ionization occurs, and the resulting equation of state achieves good agreement with the first principles simulations of fluid helium.

  5. Fluid-percussion–induced traumatic brain injury model in rats

    OpenAIRE

    2010-01-01

    Traumatic brain injury (TBI) is a major cause of mortality and morbidity. Various attempts have been made to replicate clinical TBI using animal models. The fluid-percussion model (FP) is one of the oldest and most commonly used models of experimentally induced TBI. Both central (CFP) and lateral (LFP) variations of the model have been used. Developed initially for use in larger species, the standard FP device was adapted more than 20 years ago to induce consistent degrees of brain injury in ...

  6. Nucleation speed limit on remote fluid-induced earthquakes

    Science.gov (United States)

    Parsons, Tom; Malagnini, Luca; Akinci, Aybige

    2017-01-01

    Earthquakes triggered by other remote seismic events are explained as a response to long-traveling seismic waves that temporarily stress the crust. However, delays of hours or days after seismic waves pass through are reported by several studies, which are difficult to reconcile with the transient stresses imparted by seismic waves. We show that these delays are proportional to magnitude and that nucleation times are best fit to a fluid diffusion process if the governing rupture process involves unlocking a magnitude-dependent critical nucleation zone. It is well established that distant earthquakes can strongly affect the pressure and distribution of crustal pore fluids. Earth’s crust contains hydraulically isolated, pressurized compartments in which fluids are contained within low-permeability walls. We know that strong shaking induced by seismic waves from large earthquakes can change the permeability of rocks. Thus, the boundary of a pressurized compartment may see its permeability rise. Previously confined, overpressurized pore fluids may then diffuse away, infiltrate faults, decrease their strength, and induce earthquakes. Magnitude-dependent delays and critical nucleation zone conclusions can also be applied to human-induced earthquakes. PMID:28845448

  7. Nucleation speed limit on remote fluid induced earthquakes

    Science.gov (United States)

    Parsons, Thomas E.; Akinci, Aybige; Malignini, Luca

    2017-01-01

    Earthquakes triggered by other remote seismic events are explained as a response to long-traveling seismic waves that temporarily stress the crust. However, delays of hours or days after seismic waves pass through are reported by several studies, which are difficult to reconcile with the transient stresses imparted by seismic waves. We show that these delays are proportional to magnitude and that nucleation times are best fit to a fluid diffusion process if the governing rupture process involves unlocking a magnitude-dependent critical nucleation zone. It is well established that distant earthquakes can strongly affect the pressure and distribution of crustal pore fluids. Earth’s crust contains hydraulically isolated, pressurized compartments in which fluids are contained within low-permeability walls. We know that strong shaking induced by seismic waves from large earthquakes can change the permeability of rocks. Thus, the boundary of a pressurized compartment may see its permeability rise. Previously confined, overpressurized pore fluids may then diffuse away, infiltrate faults, decrease their strength, and induce earthquakes. Magnitude-dependent delays and critical nucleation zone conclusions can also be applied to human-induced earthquakes.

  8. Modeling of movement-induced and flow-induced fluid forces in fast switching valves

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Schmidt, Lasse

    2015-01-01

    Fast switching fluid power valves set strict requirements on performance, size and energy efficiency and simulation models are therefore needed to obtain good designs of such components. The valve moving member is subject to fluid forces depending on the valve flow rate and movement of the valve...... valve design. Simulated results of the total fluid force are presented showing the movement-induced fluid force to be significant for a reference application. The model form established is useful for valve designers during development and for accurate operation simulation....... member itself. These fluid forces may be accurately simulated using Computational Fluid Dynamics (CFD) analysis, but such models suffer from being computationally expensive and is not suited for optimization routines. In this paper, a computationally inexpensive method for modeling the fluid forces...

  9. Worst-case amplification of disturbances in inertialess Couette flow of viscoelastic fluids

    CERN Document Server

    Lieu, Binh K; Kumar, Satish

    2013-01-01

    Amplification of deterministic disturbances in inertialess shear-driven channel flows of viscoelastic fluids is examined by analyzing the frequency responses from spatio-temporal body forces to the velocity and polymer stress fluctuations. In strongly elastic flows, we show that disturbances with large streamwise length scales may be significantly amplified even in the absence of inertia. For fluctuations without streamwise variations, we derive explicit analytical expressions for the dependence of the worst-case amplification (from different forcing to different velocity and polymer stress components) on the Weissenberg number ($We$), the maximum extensibility of the polymer chains ($L$), the viscosity ratio, and the spanwise wavenumber. For the Oldroyd-B model, the amplification of the most energetic components of velocity and polymer stress fields scales as $We^2$ and $We^4$. On the other hand, finite extensibility of polymer molecules limits the largest achievable amplification even in flows with infinite...

  10. Computational modeling of glow discharge-induced fluid dynamics

    Science.gov (United States)

    Jayaraman, Balaji

    Glow discharge at atmospheric pressure using a dielectric barrier discharge can induce fluid flow and operate as an actuator for flow control. The largely isothermal surface plasma generation realized above can modify the near-wall flow structure by means of Lorentzian collisions between the ionized fluid and the neutral fluid. Such an actuator has advantages of no moving parts, performance at atmospheric conditions and devising complex control strategies through the applied voltage. However, the mechanism of the momentum coupling between the plasma and the fluid flow is not yet adequately understood. In the present work, a modeling framework is presented to simulate athermal, non-equilibrium plasma discharges in conjunction with low Mach number fluid dynamics at atmospheric pressure. The plasma and fluid species are treated as a two-fluid system exhibiting a few decades of length and time scales. The effect of the plasma dynamics on the fluid dynamics is devised via a body force treatment in the Navier-Stokes equations. Two different approaches of different degrees of fidelity are presented for modeling the plasma dynamics. The first approach, a phenomenological model, is based on a linearized force distribution approximating the discharge structure, and utilizing experimental guidance to deduce the empirical constants. A high fidelity approach is to model the plasma dynamics in a self-consistent manner using a first principle-based hydrodynamic plasma model. The atmospheric pressure regime of interest here enables us to employ local equilibrium assumptions, signifying efficient collisional energy exchange as against thermal heating from inelastic collision processes. The time scale ratios between convection, diffusion, and reaction/ionization mechanisms are O(107), making the system computationally stiff. To handle the stiffness, a sequential finite-volume operator-splitting algorithm capable of conserving space charge is developed; the approach can handle time

  11. Modeling the Fluid Withdraw and Injection Induced Earthquakes

    Science.gov (United States)

    Meng, C.

    2016-12-01

    We present an open source numerical code, Defmod, that allows one to model the induced seismicity in an efficient and standalone manner. The fluid withdraw and injection induced earthquake has been a great concern to the industries including oil/gas, wastewater disposal and CO2 sequestration. Being able to numerically model the induced seismicity is long desired. To do that, one has to consider at lease two processes, a steady process that describes the inducing and aseismic stages before and in between the seismic events, and an abrupt process that describes the dynamic fault rupture accompanied by seismic energy radiations during the events. The steady process can be adequately modeled by a quasi-static model, while the abrupt process has to be modeled by a dynamic model. In most of the published modeling works, only one of these processes is considered. The geomechanicists and reservoir engineers are focused more on the quasi-static modeling, whereas the geophysicists and seismologists are focused more on the dynamic modeling. The finite element code Defmod combines these two models into a hybrid model that uses the failure criterion and frictional laws to adaptively switch between the (quasi-)static and dynamic states. The code is capable of modeling episodic fault rupture driven by quasi-static loading, e.g. due to reservoir fluid withdraw and/or injection, and by dynamic loading, e.g. due to the foregoing earthquakes. We demonstrate a case study for the 2013 Azle earthquake.

  12. Fluid Induced Earthquakes: From KTB Experiments to Natural Seismicity Swarms.

    Science.gov (United States)

    Shapiro, S. A.

    2006-12-01

    Experiments with borehole fluid injections are typical for exploration and development of hydrocarbon or geothermal reservoirs (e.g., fluid-injection experiments at Soultz, France and at Fenton-Hill, USA). Microseismicity occurring during such operations has a large potential for understanding physics of the seismogenic process as well as for obtaining detailed information about reservoirs at locations as far as several kilometers from boreholes. The phenomenon of microseismicity triggering by borehole fluid injections is related to the process of the Frenkel-Biot slow wave propagation. In the low-frequency range (hours or days of fluid injection duration) this process reduces to the pore pressure diffusion. Fluid induced seismicity typically shows several diffusion indicating features, which are directly related to the rate of spatial grow, to the geometry of clouds of micro earthquake hypocentres and to their spatial density. Several fluid injection experiments were conducted at the German Continental Deep Drilling Site (KTB) in 1994, 2000 and 2003-2005. Microseismicity occurred at different depth intervals. We analyze this microseismicity in terms of its diffusion-related features. Its relation to the 3-D distribution of the seismic reflectivity has important rock physical and tectonic implications. Starting from such diffusion-typical signatures of man-made earthquakes, we seek analogous patterns for the earthquakes in Vogtland/Bohemia at the German/Czech border region in central Europe. There is strong geophysical evidence that there seismic events are correlated to fluid-related processes in the crust. We test the hypothesis that ascending magmatic fluids trigger earthquakes by the mechanism of pore pressure diffusion. This triggering process is mainly controlled by two physical fields, the hydraulic diffusivity and the seismic criticality (i.e., critical pore pressure value leading to failure; stable locations are characterized by higher critical pressures

  13. Transition to turbulence and mixing in a viscoelastic fluid flowing inside a channel with a periodic array of cylindrical obstacles.

    Science.gov (United States)

    Grilli, Muzio; Vázquez-Quesada, Adolfo; Ellero, Marco

    2013-04-26

    Using Lagrangian simulations of a viscoelastic fluid modeled with an Oldroyd-B constitutive equation, we demonstrate that the flow through a closely spaced linear array of cylinders confined in a channel undergoes a transition to a purely elastic turbulent regime above a critical Weissenberg number (We). The high-We regime is characterized by an unsteady motion and a sudden increase in the flow resistance in qualitative agreement with experimental observations. Furthermore, a power-law scaling behavior of the integral quantities as well as enhanced mixing of mass is observed. A stability analysis based on the dynamic mode decomposition method allows us to identify the most energetic modes responsible for the unsteady behavior, which correspond to filamental structures of polymer over- or underextension advected by the main flow preserving their shape. These time-dependent flow features strictly resemble the elastic waves reported in recent numerical simulations.

  14. Interparticle Capillary Forces at a Fluid-Fluid Interface with Strong Polymer-Induced Aging.

    Science.gov (United States)

    Cappelli, Stefano; de Jong, Arthur M; Baudry, Jean; Prins, Menno W J

    2017-01-24

    We report on a measurement of forces between particles adsorbed at a water-oil interface in the presence of an oil-soluble polymer. The cationic polymer interacts electrostatically with the negatively charged particles, thereby modulating the particle contact angle and the magnitude of capillary attraction between the particles. However, polymer adsorption to the interface also generates an increase in the apparent interfacial viscosity over several orders of magnitude in a time span of a few hours. We have designed an experiment in which repeated motion trajectories are measured on pairs of particles. The experiment gives an independent quantification of the interfacial drag coefficient (10(-7)-10(-4) Ns/m) and of the interparticle capillary forces (0.1-10 pN). We observed that the attractive capillary force depends on the amount of polymer in the oil phase and on the particle pair. However, the attraction appears to be independent of the surface rheology, with changes over a wide range of apparent viscosity values due to aging. Given the direction (attraction), the range (∼μm), and the distance dependence (∼1/S(5)) of the observed interparticle force, we interpret the force as being caused by quadrupolar deformations of the fluid-fluid interface induced by particle surface roughness. The results suggest that capillary forces are equilibrated in the early stages of interface aging and thereafter do not change anymore, even though strong changes in surface rheology still occur. The described experimental approach is powerful for studying dissipative as well as conservative forces of micro- and nanoparticles at fluid-fluid interfaces for systems out of equilibrium.

  15. Modeling Microgravity Induced Fluid Redistribution Autoregulatory and Hydrostatic Enhancements

    Science.gov (United States)

    Myers, J. G.; Werner, C.; Nelson, E. S.; Feola, A.; Raykin, J.; Samuels, B.; Ethier, C. R.

    2017-01-01

    Space flight induces a marked cephalad (headward) redistribution of blood and interstitial fluid potentially resulting in a loss of venous tone and reduction in heart muscle efficiency upon introduction into the microgravity environment. Using various types of computational models, we are investigating how this fluid redistribution may induce intracranial pressure changes, relevant to reported reductions in astronaut visual acuity, part of the Visual Impairment and Intracranial Pressure (VIIP) syndrome. Methods: We utilize a lumped parameter cardiovascular system (CVS) model, augmented by compartments comprising the cerebral spinal fluid (CSF) space, as the primary tool to describe how microgravity, and the associated lack of hydrostatic gradient, impacts fluid redistribution. Models of ocular fluid pressures and biomechanics then accept the output of the above model as boundary condition input to allow more detailed, local analysis (see IWS Abstract by Ethier et al.). Recently, we enhanced the capabilities our previously reported CVS model through the implementation of robust autoregulatory mechanisms and a more fundamental approach to the implementation of hydrostatic mechanisms. Modifying the approach of Blanco et al., we implemented auto-regulation in a quasi-static manner, as an averaged effect across the span of one heartbeat. This approach reduced the higher frequency perturbations from the regulatory mechanism and was intended to allow longer simulation times (days) than models that implement within-beat regulatory mechanisms (minutes). A more fundamental approach to hydrostatics was implemented by a quasi-1D approach, in which compartment descriptions include compartment length, orientation and relative position, allowed for modeling of body orientation, relative body positioning and, in the future, alternative gravity environments. At this time the inclusion of hydrostatic mechanisms supplies additional capabilities to train and validate the CVS model

  16. Investigation of magneto-induced linear dichroism of magnetic fluid.

    Science.gov (United States)

    Du, Bobo; Yang, Dexing; Bai, Yang; Yuan, Yuan; Mao, Dong; Zhang, Wending; She, Xiaoyang

    2017-01-20

    A fiber-optic component is fabricated with etched fiber coated by magnetic fluid (MF) for its evanescent field to be modulated by the MF. The magneto-induced linear dichroism of the MF is investigated under different temperatures with the component. The experimental results show that the MF possesses weak linear dichroism (maximum of 2.37% at 25°C) caused by its sparse magneto-induced chains. Considering the relationships between the linear dichroisms and temperature, there is a transition point of magnetic field at ∼4  mT. Up to ∼4  mT, the linear dichroisms decrease with the temperature; however, for higher magnetic field strengths, the linear dichroisms increase with the temperature. Interestingly, a small initial linear dichroism (up to 0.255% at 5°C) without magnetic field is also observed.

  17. Fluid patterns and dynamics induced by vibrations in microgravity conditions

    Science.gov (United States)

    Porter, Jeff; Tinao Perez-Miravete, Ignacio; Laverón-Simavilla, Ana

    Understanding the effects of vibrations is extremely important in microgravity environments where residual acceleration, or g-jitter, is easily generated by crew manoeuvring or machinery, and can have a significant impact on material processing systems and on-board experiments. Indeed, vibrations can dramatically affect fluid behaviour whether gravity is present or not, inducing instability in some cases while suppressing it in others. We will describe the results of investigations being conducted at the ESA affiliated Spanish User Support and Operations Centre (E-USOC) on the effect of vibrations on fluids interfaces, most notably with the forcing oriented parallel to the fluid surface. Pattern formation properties will be described in detail, and the importance of symmetry constraints and mean flows will be considered. Current exper-imental results are intriguing and have challenged existing assumptions in the field, particularly with regard to the parametric instability underlying subharmonic cross-waves. They suggest an intimate connection between Faraday waves, which are observed in vertically vibrated systems, and cross-waves, which are found in horizontally forced systems. Concurrent theoretical work, based on the analysis of reduced models, and on numerical simulations, will then be described. Finally, this research will be placed in a microgravity context and used to motivate the defini-tion of a proposed set of experiments on the International Space Station (ISS). The experiments would be in the large-aspect-ratio-limit, requiring relatively high frequency but low amplitude vibrations, where comparatively little microgravity research has been done. The interest of such a microgravity experiment will be discussed, with emphasis on fluid management and the potential of vibrations to act as a kind of artificial gravity by orienting surfaces (or density contours) perpendicular to the axis of vibration.

  18. Geometry-induced Casimir suspension of oblate bodies in fluids.

    Science.gov (United States)

    Rodriguez, Alejandro W; Reid, M T Homer; Intravaia, Francesco; Woolf, Alexander; Dalvit, Diego A R; Capasso, Federico; Johnson, Steven G

    2013-11-01

    We predict that a low-permittivity oblate body (disk-shaped object) above a thin metal substrate (plate with a hole) immersed in a fluid of intermediate permittivity will experience a metastable equilibrium (restoring force) near the center of the hole. Stability is the result of a geometry-induced transition in the sign of the force, from repulsive to attractive, that occurs as the disk approaches the hole--in planar or nearly planar geometries, the same material combination yields a repulsive force at all separations, in accordance with the Dzyaloshinskiĭ-Lifshitz-Pitaevskiĭ condition of fluid-induced repulsion between planar bodies. We explore the stability of the system with respect to rotations and lateral translations of the disks and demonstrate interesting transitions (bifurcations) in the rotational stability of the disks as a function of their size. Finally, we consider the reciprocal situation in which the disk-plate materials are interchanged and find that in this case the system also exhibits metastability. The forces in the system are sufficiently large to be observed in experiments and should enable measurements based on the diffusion dynamics of the suspended bodies.

  19. Inducible nitric oxide synthase is expressed in synovial fluid granulocytes.

    Science.gov (United States)

    Cedergren, J; Forslund, T; Sundqvist, T; Skogh, T

    2002-10-01

    The objective of the study was to evaluate the NO-producing potential of synovial fluid (SF) cells. SF from 15 patients with arthritis was compared with blood from the same individuals and with blood from 10 healthy controls. Cellular expression of inducible nitric oxide synthase (iNOS) was analysed by flow cytometry. High-performance liquid chromatography was used to measure l-arginine and l-citrulline. Nitrite and nitrate were measured colourimetrically utilizing the Griess' reaction. Compared to whole blood granulocytes in patients with chronic arthritis, a prominent iNOS expression was observed in SF granulocytes (P < 0.001). A slight, but statistically significant, increase in iNOS expression was also recorded in lymphocytes and monocytes from SF. l-arginine was elevated in SF compared to serum (257 +/- 78 versus 176 +/- 65 micro mol/l, P = 0.008), whereas a slight increase in l-citrulline (33 +/- 11 versus 26 +/- 9 micro mol/l), did not reach statistical significance. Great variations but no significant differences were observed comparing serum and SF levels of nitrite and nitrate, respectively, although the sum of nitrite and nitrate tended to be elevated in SF (19.2 +/- 20.7 versus 8.6 +/- 6.5 micro mol/l, P = 0.054). Synovial fluid leucocytes, in particular granulocytes, express iNOS and may thus contribute to intra-articular NO production in arthritis.

  20. Cavitation-induced ignition of cryogenic hydrogen-oxygen fluids

    Science.gov (United States)

    Osipov, V. V.; Muratov, C. B.; Ponizovskaya-Devine, E.; Foygel, M.; Smelyanskiy, V. N.

    2011-03-01

    The Challenger disaster and purposeful experiments with liquid hydrogen (H2) and oxygen (Ox) tank breaches demonstrated that cryogenic H2/Ox fluids always self-ignite in the process of their sudden mixing. Here, we propose a cavitation-induced self-ignition mechanism that may be realized under these conditions. In one possible scenario, self-ignition is caused by the strong shock waves generated by the collapse of pure Ox vapor bubble near the surface of the Ox liquid that may initiate detonation of the gaseous H2/Ox mixture next to the gas-liquid interface. This effect is further enhanced by H2/Ox combustion inside the collapsing bubble in the presence of admixed H2 gas.

  1. Cavitation-induced ignition of cryogenic hydrogen-oxygen fluids

    CERN Document Server

    Osipov, V V; Ponizovskya-Devine, E; Foygel, M; Smelyanskiy, V N

    2011-01-01

    The Challenger disaster and purposeful experiments with liquid hydrogen (H2) and oxygen (Ox) tanks demonstrated that cryogenic H2/Ox fluids always self-ignite in the process of their mixing. Here we propose a cavitation-induced self-ignition mechanism that may be realized under these conditions. In one possible scenario, self-ignition is caused by the strong shock waves generated by the collapse of pure Ox vapor bubble near the surface of the Ox liquid that may initiate detonation of the gaseous H2/Ox mixture adjacent to the gas-liquid interface. This effect is further enhanced by H2/Ox combustion inside the collapsing bubble in the presence of admixed H2 gas.

  2. Dynamic response of shear thickening fluid under laser induced shock

    Science.gov (United States)

    Wu, Xianqian; Zhong, Fachun; Yin, Qiuyun; Huang, Chenguang

    2015-02-01

    The dynamic response of the 57 vol./vol. % dense spherical silica particle-polyethylene glycol suspension at high pressure was investigated through short pulsed laser induced shock experiments. The measured back free surface velocities by a photonic Doppler velocimetry showed that the shock and the particle velocities decreased while the shock wave transmitted in the shear thickening fluid (STF), from which an equation of state for the STF was obtained. In addition, the peak stress decreased and the absorbed energy increased rapidly with increasing the thickness for a thin layer of the STF, which should be attributed to the impact-jammed behavior through compression of particle matrix, the deformation or crack of the hard-sphere particles, and the volume compression of the particles and the polyethylene glycol.

  3. Energy amplification in channel flows of viscoelastic fluids

    Science.gov (United States)

    Hoda, Nazish; Jovanovi?, Mihailo R.; Kumar, Satish

    Energy amplification in channel flows of Oldroyd-B fluids is studied from an input-output point of view by analysing the ensemble-average energy density associated with the velocity field of the linearized governing equations. The inputs consist of spatially distributed and temporally varying body forces that are harmonic in the streamwise and spanwise directions and stochastic in the wall-normal direction and in time. Such inputs enable the use of powerful tools from linear systems theory that have recently been applied to analyse Newtonian fluid flows. It is found that the energy density increases with a decrease in viscosity ratio (ratio of solvent viscosity to total viscosity) and an increase in Reynolds number and elasticity number. In most of the cases, streamwise-constant perturbations are most amplified and the location of maximum energy density shifts to higher spanwise wavenumbers with an increase in Reynolds number and elasticity number and a decrease in viscosity ratio. For similar parameter values, the maximum in the energy density occurs at a higher spanwise wavenumber for Poiseuille flow, whereas the maximum energy density achieves larger maxima for Couette flow. At low Reynolds numbers, the energy density decreases monotonically when the elasticity number is sufficiently small, but shows a maximum when the elasticity number becomes sufficiently large, suggesting that elasticity can amplify disturbances even when inertial effects are weak.

  4. Small-amplitude swimmers can self-propel faster in viscoelastic fluids.

    Science.gov (United States)

    Riley, Emily E; Lauga, Eric

    2015-10-01

    Many small organisms self-propel in viscous fluids using travelling wave-like deformations of their bodies or appendages. Examples include small nematodes moving through soil using whole-body undulations or spermatozoa swimming through mucus using flagellar waves. When self-propulsion occurs in a non-Newtonian fluid, one fundamental question is whether locomotion will occur faster or slower than in a Newtonian environment. Here we consider the general problem of swimming using small-amplitude periodic waves in a viscoelastic fluid described by the classical Oldroyd-B constitutive relationship. Using Taylor's swimming sheet model, we show that if all travelling waves move in the same direction, the locomotion speed of the organism is systematically decreased. However, if we allow waves to travel in two opposite directions, we show that this can lead to enhancement of the swimming speed, which is physically interpreted as due to asymmetric viscoelastic damping of waves with different frequencies. A change of the swimming direction is also possible. By analysing in detail the cases of swimming using two or three travelling waves, we demonstrate that swimming can be enhanced in a viscoelastic fluid for all Deborah numbers below a critical value or, for three waves or more, only for a finite, non-zero range of Deborah numbers, in which case a finite amount of elasticity in the fluid is required to increase the swimming speed.

  5. NUMERICAL ANALYSIS OF FLUID FLOW AND ADDED MASS INDUCED BY VIBRATION OF STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    SU Li; LI Shu-juan; TANG Guo-an

    2005-01-01

    The fluid flow induced by light-density, low-stiffness structures was treated as inviscid, incompressible irrotational and steady plane flow. On the basis of the dipole configuration method, a singularity distribution method of distributing sources/sinks and dipoles on interfaces of the structure and fluid was developed to solve the problem of fluid flow induced by the vibration of common structures, such as columns and columns with fins,deduce the expression of kinetic energy of the fluid flow, and obtain the added mass finally.The calculational instances with analytical solutions prove the reliability of this method.

  6. Simulations of flow induced ordering in viscoelastic fluids

    NARCIS (Netherlands)

    Santos de Oliveira, I.S.

    2012-01-01

    In this thesis we report on simulations of colloidal ordering phenomena in shearthinning viscoelastic fluids under shear flow. Depending on the characteristics of the fluid, the colloids are observed to align in the direction of the flow. These string-like structures remain stable as long as the she

  7. Role of passive body dynamics in micro-organism swimming in complex fluids

    Science.gov (United States)

    Thomases, Becca; Guy, Robert

    2016-11-01

    We investigate the role of passive body dynamics in the kinematics of swimming micro-organisms in complex fluids. Asymptotic analysis and linear theory are used to predict shape changes that result as body elasticity and fluid elasticity are varied. The analysis is compared with a computational model of a finite length swimmer in a Stokes-Oldroyd-B fluid. Simulations and theory agree quantitatively for small amplitude motions with low fluid elasticity (Deborah number). This may not be surprising as the theory is expected hold in these two regimes. What is more remarkable is that the predicted shape changes match the computational shape changes quantitatively for large amplitudes, even for large Deborah numbers. Shape changes only tell part of the story. Swimming speed depends on other effects as well. We see that shape changes can predict swimming speed well when either the amplitude is small (including large Deborah number) or when the Deborah number is small (including large amplitudes). It is only in the large De AND large amplitude regime where the theory breaks down and swimming speed can no longer be inferred from shape changes alone.

  8. Fluid-induced Blueschist Preservation on Syros, Cyclades, Southern Greece

    Science.gov (United States)

    Kleine, B. I.; Huet, B.; Skelton, A. D. L.

    2012-04-01

    Local examples of preservation of high-pressure, low-temperature (HP-LT) mineral assemblages within retrograde metamorphosed greenschist are recorded from the Cyclades, Greece. Several models have been proposed to explain the preservation of HP-LT rocks in these areas. On Sifnos, a capping effect of impermeable marble units below the preserved blueschists caused diversion of the upward, cross-layer infiltration of retrograde fluids [1]. On Tinos, blueschist preservation occurred due to retrograde fluid flow channelization along lithological contacts with high flux rates [2]. HP-LT minerals were preserved in regions adjacent to these contacts where fluid fluxes were smaller. We propose a different mechanism of blueschist preservation based on observations from a costal section near Fabrika on Syros. At this locality a high strain zone cuts through a retrograde greenschist. Along the fault a dark blue halo occurs within the greenschist. Whole rock analyses along a profile from the fault into the greenschist show that only the areas directly adjacent to the deformation zone show chemical evidence of metasomatism, whereas the areas further away are chemically similar to greenschist. Point counting of 1000 evenly spaced points in thin sections of the profile shows a clear blueschist to greenschist transition with a blueschist mineral assemblage (glaucophane+phengite+calcite) nearer to the metasomatic zone and a typical greenschist mineral assemblage (epidote+chlorite+albite) farther away. We propose the following model to explain preservation of HP-LT mineral assemblage in this locality. During retrograde metamorphism a water-rich fluid infiltrated the blueschist rock from below. This occurred close to the brittle-ductile transition. This fluid caused a reaction front to propagate into the overlying blueschist at which its mineral assemblage glaucophane+phengite+calcite was replaced by the greenschist mineral assemblage epidote+albite+chlorite. Upwards-flowing fluid

  9. Flexibility, stroke, and dimensionless parameters: the importance of telling the whole story for swimming micro-organisms in complex fluids

    Science.gov (United States)

    Thomases, Becca; Guy, Robert

    2015-11-01

    The question of how fluid elasticity affects the swimming performance of micro-organisms is complicated and has been the subject of many recent experimental and theoretical studies. The Deborah number, De = λω , is typically used to characterize the strength of the fluid elasticity in these studies, and for swimmers is expressed as the product of the elastic relaxation time and the frequency of the swimmer stroke. In simulations of undulatory flexible swimmers in an Oldroyd-B-type fluid, we find that varying the frequency of the stroke and varying the relaxation time separately results in a significantly different dependence of swimming speed for the same De . Thus the elastic effects on swimming cannot be characterized by a single dimensionless number. The Weissenberg number, defined as the product of elastic relaxation time and characteristic strain rate (Wi = λγ˙), is another dimensionless parameter useful for describing complex fluids. For a fixed swimmer frequency, varying the relaxation time will also vary the Weissenberg number. We conjecture that the different behavior is a consequence of a Weissenberg-number transition in the fluid, which additionally depends on the amplitude of the swimmer stroke.

  10. Dynamics of particle sedimentation in viscoelastic fluids: A numerical study on particle chain in two-dimensional narrow channel

    CERN Document Server

    Pan, Tsorng-Whay

    2016-01-01

    In this article we present a numerical method for simulating the sedimentation of circular particles in two-dimensional channel filled with a viscoelastic fluid of FENE-CR type, which is generalized from a domain/distributed Lagrange multiplier method with a factorization approach for Oldroyd-B fluids developed in [J. Non-Newtonian Fluid Mech. 156 (2009) 95]. Numerical results suggest that the polymer extension limit L for the FENE-CR fluid has no effect on the final formation of vertical chain for the cases of two disks and three disks in two-dimensional narrow channel, at least for the values of L considered in this article; but the intermediate dynamics of particle interaction before having a vertical chain can be different for the smaller values of L when increasing the relaxation time. For the cases of six particles sedimenting in FENE-CR type viscoelastic fluid, the formation of chain of 4 to 6 disks does depend on the polymer extension limit L. For the smaller values of L, FENE-CR type viscoelastic flu...

  11. Linear instability of the electrified free interface between two cylindrical shells of viscoelastic fluids through porous media

    Institute of Scientific and Technical Information of China (English)

    Magdy A.Sirwah

    2012-01-01

    In this paper,we have discussed the linear stability analysis of the electrified surface separating two coaxial Oldroyd-B fluid layers confined between two impermeable rigid cylinders in the presence of both interfacial insoluble surfactant and surface charge through porous media.The case of long waves interfacial stability has been studied.The dispersion relation is solved numerically and hence the effects of various parameters are illustrated graphically.Our results reveal that the influence of the physicochemical parameterβ is to shrink the instability region of the surface and reduce the growth rate of the unstable normal modes.Such important effects of the surfactant on the shape of interfacial structures are more sensitive to the variation of the β corresponding to non-Newtonian fluids-model compared with the Newtonian fluids model.In the case of long wave limit,it is demonstrated that increasingβ,has a dual role influence (de-stabilizing effects) depending on the viscosity of the core fluid.It has a destabilizing effect at the large values of the core fluid viscosity coefficient,while this role is exchanged to a regularly stabilizing influence at small values of such coefficient.

  12. Non-modal energy amplification in channel flows of viscoelastic fluids

    Science.gov (United States)

    Jovanovic, Mihailo; Hoda, Nazish; Kumar, Satish

    2008-11-01

    Energy amplification in channel flows of Oldroyd-B fluids is studied from an input-output point of view by analyzing the responses of the velocity components to spatio-temporal body forces. These inputs into the governing linearized equations are assumed to be harmonic in the streamwise and spanwise directions and stochastic in the wall-normal direction and in time. Such inputs enable the use of powerful tools from linear systems theory that have recently been applied to analyze Newtonian fluid flows. It is found that the energy amplification increases with a decrease in viscosity ratio and increase in Reynolds number and elasticity number. In most of the cases, streamwise constant perturbations are most amplified and the location of maximum energy amplification shifts to higher spanwise wavenumbers with an increase in Reynolds number and elasticity number and decrease in viscosity ratio. For streamwise constant perturbations, an explicit Reynolds number scaling of energy amplification from different forcing to different velocity components is developed, showing the same Re-dependence as in Newtonian fluids. At low Reynolds numbers, the energy amplification decreases monotonically when the elasticity number is sufficiently small, but shows a maximum when the elasticity number becomes sufficiently large, suggesting that elasticity can amplify disturbances even when inertial effects are weak.

  13. Facial Soft Tissue Measurement in Microgravity-induces Fluid Shifts

    Science.gov (United States)

    Marshburn, Thomas; Cole, Richard; Pavela, James; Garcia, Kathleen; Sargsyan, Ashot

    2014-01-01

    Fluid shifts are a well-known phenomenon in microgravity, and one result is facial edema. Objective measurement of tissue thickness in a standardized location could provide a correlate with the severity of the fluid shift. Previous studies of forehead tissue thickness (TTf) suggest that when exposed to environments that cause fluid shifts, including hypergravity, head-down tilt, and high-altitude/lowpressure, TTf changes in a consistent and measurable fashion. However, the technique in past studies is not well described or standardized. The International Space Station (ISS) houses an ultrasound (US) system capable of accurate sub-millimeter measurements of TTf. We undertook to measure TTf during long-duration space flight using a new accurate, repeatable and transferable technique. Methods: In-flight and post-flight B-mode ultrasound images of a single astronaut's facial soft tissues were obtained using a Vivid-q US system with a 12L-RS high-frequency linear array probe (General Electric, USA). Strictly mid-sagittal images were obtained involving the lower frontal bone, the nasofrontal angle, and the osseo-cartilaginous junction below. Single images were chosen for comparison that contained identical views of the bony landmarks and identical acoustical interface between the probe and skin. Using Gingko CADx DICOM viewing software, soft tissue thickness was measured at a right angle to the most prominent point of the inferior frontal bone to the epidermis. Four independent thickness measurements were made. Conclusions: Forehead tissue thickness measurement by ultrasound in microgravity is feasible, and our data suggest a decrease in tissue thickness upon return from microgravity environment, which is likely related to the cessation of fluid shifts. Further study is warranted to standardize the technique with regard to the individual variability of the local anatomy in this area.

  14. Patterns of gravity induced aggregate migration during casting of fluid concretes

    DEFF Research Database (Denmark)

    Spangenberg, Jon; Roussel, N.; Hattel, Jesper Henri

    2012-01-01

    In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in...... that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.......In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting...

  15. Pharmacokinetic Profile of Meropenem, Administered at 500 Milligrams Every 8 Hours, in Plasma and Cantharidin-Induced Skin Blister Fluid

    OpenAIRE

    Maglio, Dana; Teng, Renli; Thyrum, Per T.; Nightingale, Charles H.; Nicolau, David P.

    2003-01-01

    The pharmacokinetic disposition of meropenem, administered at 500 mg every 8 h, in plasma and cantharidin-induced blister fluid is described. Peak meropenem concentrations in blister fluid lagged behind peak meropenem concentrations in plasma, while a lower elimination rate from blister fluid was also noted. The mean penetration of meropenem into blister fluid was 67%. The pharmacokinetic profile of meropenem in blister fluid supports the utility of this dose in the management of skin and sof...

  16. Pharmacokinetic profile of meropenem, administered at 500 milligrams every 8 hours, in plasma and cantharidin-induced skin blister fluid.

    Science.gov (United States)

    Maglio, Dana; Teng, Renli; Thyrum, Per T; Nightingale, Charles H; Nicolau, David P

    2003-05-01

    The pharmacokinetic disposition of meropenem, administered at 500 mg every 8 h, in plasma and cantharidin-induced blister fluid is described. Peak meropenem concentrations in blister fluid lagged behind peak meropenem concentrations in plasma, while a lower elimination rate from blister fluid was also noted. The mean penetration of meropenem into blister fluid was 67%. The pharmacokinetic profile of meropenem in blister fluid supports the utility of this dose in the management of skin and soft tissue infections.

  17. Simulation of Vocal Folds: A Fluid-Induced Self-Oscillating Problem

    Science.gov (United States)

    Wang, Xingshi; Zhang, Lucy

    2009-11-01

    The goal of this study is to investigate the process of voice production by simulating the motion and deformation of human vocal folds. The vocal folds are oscillated by a constant lung pressure driven airflow in the throat. The system is modeled in 2-D using the immersed finite element method to simulate and study the fluid-structure interaction mechanism. From our numerical results, the glottal jets are identified. Several parameters such as the Reynolds number, Strouhal number, vocal folds stiffness, density ratio between the fluid and the structure are addressed and compared with experimental results. The frequency of the vocal folds vibration, fluid flow rate and pressure distribution are also investigated. In addition, the energy transfer between the fluid domain and the solid domain are analyzed to assist in explaining the underlying physical mechanism for this fluid-induced self-oscillating vocal folds.

  18. Fluid-like elasticity induced by anisotropic effective mass density

    DEFF Research Database (Denmark)

    Ma, Guancong; Fu, Caixing; Wang, Guanghao

    We present a three-dimensional anisotropic elastic metamaterial, which can generate dipolar resonances. Repeating these subwavelength units can lead to one-dimensional arrays, which are essentially elastic rods that can withstand both longitudinal, and flexural vibrations. Band structure analysis...... scenarios such as civil engineering and seismic wave control....... shows the systems can have distinctive responses to waves with each polarization. In particular, we demonstrate that only longitudinal wave can propagate within a finite frequency regime, whereas transverse (flexural) waves meet a bandgap — a property conventionally found only in fluids. Effective...

  19. Localized microstructures induced by fluid flow in directional solidification.

    Science.gov (United States)

    Jamgotchian, H; Bergeon, N; Benielli, D; Voge, P; Billia, B; Guérin, R

    2001-10-15

    The dynamical process of microstructure localization by multiscale interaction between instabilities is uncovered in directional solidification of transparent alloy. As predicted by Chen and Davis, morphological instability of the interface is observed at inward flow-stagnation regions of the cellular convective field. Depending on the driving force of fluid flow, focus-type and honeycomb-type localized patterns form in the initial transient of solidification, that then evolves with time. In the case of solute-driven flow, the analysis of the onset of thermosolutal convection in initial transient of solidification enables a complete understanding of the dynamics and of the localization of morphological instability.

  20. Electric Field-Induced Fluid Velocity Field Distribution in DNA Solution

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling-Yun; WANG Peng-Ye

    2008-01-01

    We present an analytical solution for fluid velocity field distribution of polyelectrolyte DNA. Both the electric field force and the viscous force in the DNA solution are considered under a suitable boundary condition. The solution of electric potential is analytically obtained by using the linearized Poisson-Boltzmann equation. The fluid velocity along the electric field is dependent on the cylindrical radius and concentration. It is shown that the electric field-induced fluid velocity will be increased with the increasing cylindrical radius, whose distribution also varies with the concentration

  1. Laboratory simulations of fluid/gas induced micro-earthquakes: application to volcano seismology.

    Directory of Open Access Journals (Sweden)

    Philip Michael Benson

    2014-11-01

    Full Text Available Understanding different seismic signals recorded in active volcanic regions allows geoscientists to derive insight into the processes that generate them. A key type is known as Low Frequency or Long Period (LP event, generally understood to be generated by different fluid types resonating in cracks and faults. The physical mechanisms of these signals have been linked to either resonance/turbulence within fluids, or as a result of fluids ‘sloshing’ due to a mixture of gas and fluid being present in the system. Less well understood, however, is the effect of the fluid type (phase on the measured signal. To explore this, we designed an experiment in which we generated a precisely controlled liquid to gas transition in a closed system by inducing rapid decompression of fluid-filled fault zones in a sample of basalt from Mt. Etna Volcano, Italy. We find that fluid phase transition is accompanied by a marked frequency shift in the accompanying microseismic dataset that can be compared to volcano seismic data. Moreover, our induced seismic activity occurs at pressure conditions equivalent to hydrostatic depths of 200 to 750 meters. This is consistent with recently measured dominant frequencies of LP events and with numerous models.

  2. Stokes' second problem for magnetohydrodynamics flow in a Burgers' fluid: the cases γ = λ²/4 and γ>λ²/4.

    Directory of Open Access Journals (Sweden)

    Ilyas Khan

    Full Text Available The present work is concerned with exact solutions of Stokes second problem for magnetohydrodynamics (MHD flow of a Burgers' fluid. The fluid over a flat plate is assumed to be electrically conducting in the presence of a uniform magnetic field applied in outward transverse direction to the flow. The equations governing the flow are modeled and then solved using the Laplace transform technique. The expressions of velocity field and tangential stress are developed when the relaxation time satisfies the condition γ =  λ²/4 or γ> λ²/4. The obtained closed form solutions are presented in the form of simple or multiple integrals in terms of Bessel functions and terms with only Bessel functions. The numerical integration is performed and the graphical results are displayed for the involved flow parameters. It is found that the velocity decreases whereas the shear stress increases when the Hartmann number is increased. The solutions corresponding to the Stokes' first problem for hydrodynamic Burgers' fluids are obtained as limiting cases of the present solutions. Similar solutions for Stokes' second problem of hydrodynamic Burgers' fluids and those for Newtonian and Oldroyd-B fluids can also be obtained as limiting cases of these solutions.

  3. Stokes' second problem for magnetohydrodynamics flow in a Burgers' fluid: the cases γ = λ²/4 and γ>λ²/4.

    Science.gov (United States)

    Khan, Ilyas; Ali, Farhad; Shafie, Sharidan

    2013-01-01

    The present work is concerned with exact solutions of Stokes second problem for magnetohydrodynamics (MHD) flow of a Burgers' fluid. The fluid over a flat plate is assumed to be electrically conducting in the presence of a uniform magnetic field applied in outward transverse direction to the flow. The equations governing the flow are modeled and then solved using the Laplace transform technique. The expressions of velocity field and tangential stress are developed when the relaxation time satisfies the condition γ =  λ²/4 or γ> λ²/4. The obtained closed form solutions are presented in the form of simple or multiple integrals in terms of Bessel functions and terms with only Bessel functions. The numerical integration is performed and the graphical results are displayed for the involved flow parameters. It is found that the velocity decreases whereas the shear stress increases when the Hartmann number is increased. The solutions corresponding to the Stokes' first problem for hydrodynamic Burgers' fluids are obtained as limiting cases of the present solutions. Similar solutions for Stokes' second problem of hydrodynamic Burgers' fluids and those for Newtonian and Oldroyd-B fluids can also be obtained as limiting cases of these solutions.

  4. Electromagnetically induced vorticity control in a quantum fluid velocity field

    CERN Document Server

    Raptis, T E

    2013-01-01

    A new method is reported by which it is possible to induce certain flux configurations of desired characteristics via electromagnetic means into the overall quantum probability current of a many-body system in the Madelung hydrodynamic picture. Some indicative applications are also considered with emphasis in HTC and gravitational wave research.

  5. On the feasibility of inducing oil mobilization in existing reservoirs via wellbore harmonic fluid action

    KAUST Repository

    Jeong, Chanseok

    2011-03-01

    Although vibration-based mobilization of oil remaining in mature reservoirs is a promising low-cost method of enhanced oil recovery (EOR), research on its applicability at the reservoir scale is still at an early stage. In this paper, we use simplified models to study the potential for oil mobilization in homogeneous and fractured reservoirs, when harmonically oscillating fluids are injected/produced within a well. To this end, we investigate first whether waves, induced by fluid pressure oscillations at the well site, and propagating radially and away from the source in a homogeneous reservoir, could lead to oil droplet mobilization in the reservoir pore-space. We discuss both the fluid pore-pressure wave and the matrix elastic wave cases, as potential agents for increasing oil mobility. We then discuss the more realistic case of a fractured reservoir, where we study the fluid pore-pressure wave motion, while taking into account the leakage effect on the fracture wall. Numerical results show that, in homogeneous reservoirs, the rock-stress wave is a better energy-delivery agent than the fluid pore-pressure wave. However, neither the rock-stress wave nor the pore-pressure wave is likely to result in any significant residual oil mobilization at the reservoir scale. On the other hand, enhanced oil production from the fractured reservoir\\'s matrix zone, induced by cross-flow vibrations, appears to be feasible. In the fractured reservoir, the fluid pore-pressure wave is only weakly attenuated through the fractures, and thus could induce fluid exchange between the rock formation and the fracture space. The vibration-induced cross-flow is likely to improve the imbibition of water into the matrix zone and the expulsion of oil from it. © 2011 Elsevier B.V.

  6. Thermally induced fluid reversed hexagonal (H(II)) mesophase.

    Science.gov (United States)

    Amar-Yuli, Idit; Wachtel, Ellen; Shalev, Deborah E; Moshe, Hagai; Aserin, Abraham; Garti, Nissim

    2007-12-06

    In the present study we characterized the microstructures of the Lc and HII phases in a glycerol monooleate (GMO)/tricaprylin (TAG)/water mixture as a function of temperature. We studied the factors that govern the formation of a low-viscosity HII phase at relatively elevated temperatures (>35 degrees C). This phase has very valuable physical characteristics and properties. The techniques used were differential scanning calorimetry (DSC), wide- and small-angle X-ray scattering (WAXS and SAXS, respectively), NMR (self-diffusion and (2)H NMR), and Fourier transform infrared (FTIR) spectroscopies. The reverse hexagonal phase exhibited relatively rapid flow of water in the inner channels within the densely packed cylindrical aggregates of GMO with TAG molecules located in the interstices. The existence of two water diffusion peaks reflects the existence of both mobile water and hydration water at the GMO-water interface (hydrogen exchange between the GMO hydroxyls and water molecules). Above 35 degrees C, the sample became fluid yet hexagonal symmetry was maintained. The fluidity of the HII phase is explained by a significant reduction in the domain size and also perhaps cylinder length. This phenomenon was characterized by higher mobility of the GMO, lower mobility of the water, and a significant dehydration process.

  7. Heat transfer with thermal radiation on MHD particle-fluid suspension induced by metachronal wave

    Science.gov (United States)

    Bhatti, M. M.; Zeeshan, A.; Ellahi, R.

    2017-09-01

    In this article, effects of heat transfer on particle-fluid suspension induced by metachronal wave have been examined. The influence of magnetohydrodynamics (MHD) and thermal radiation are also taken into account with the help of Ohm's law and Roseland's approximation. The governing flow problem for Casson fluid model is based on continuity, momentum and thermal energy equation for fluid phase and particle phase. Taking the approximation of long wavelength and zero Reynolds number, the governing equations are simplified. Exact solutions are obtained for the coupled partial differential equations. The impact of all the embedding parameters is discussed with the help of graphs. In particular, velocity profile, pressure rise, temperature profile and trapping phenomena are discussed for all the emerging parameters. It is observed that while fluid parameter enhances the velocity profile, Hartmann number and particle volume fraction oppose the flow.

  8. The Effect of Internal Fluid on the Response of Vortex-Induced Vibration of Marine Risers

    Institute of Scientific and Technical Information of China (English)

    郭海燕; 王元斌; 傅强

    2004-01-01

    Based on Iwan′s wake oscillator model developed with the classical van der Pol equation, the differential equation for the response of the vortex-induced vibration (VIV) of the riser considering the effect of the internal flowing fluid and the external marine environmental condition is derived. The effect of the internal flowing fluid on the response of VIV of the riser is studied by means of the Finite Element Method. The results show that the effect of the internal fluid velocity on the VIV of the riser is strong when the natural frequency of the riser is close to the vortex shedding frequency. In addition, the increase of the top tension can decrease the sensitivity of the riser to the internal fluid velocity.

  9. Heat transfer with thermal radiation on MHD particle–fluid suspension induced by metachronal wave

    Indian Academy of Sciences (India)

    M M BHATTI; A ZEESHAN; R ELLAHI

    2017-09-01

    In this article, effects of heat transfer on particle–fluid suspension induced by metachronal wave have been examined. The influence of magnetohydrodynamics (MHD) and thermal radiation are also taken into account with the help of Ohm’s law and Roseland’s approximation. The governing flow problem for Casson fluid model is based on continuity, momentum and thermal energy equation for fluid phase and particle phase. Taking the approximation of long wavelength and zero Reynolds number, the governing equations are simplified. Exact solutions are obtained for the coupled partial differential equations. The impact of all the embedding parameters is discussed with the help of graphs. In particular, velocity profile, pressure rise, temperature profile and trapping phenomena are discussed for all the emerging parameters. It is observed that while fluid parameter enhances the velocity profile, Hartmann number and particle volume fraction oppose the flow.

  10. Induced fluid rotation and bistable fluidic turn-down valves (a survey

    Directory of Open Access Journals (Sweden)

    Tesař Václav

    2015-01-01

    Full Text Available Paper surveys engineering applications of an unusual fluidic principle — momentum transfer through a relatively small communicating window into a vortex chamber, where the initially stationary fluid is put into rotation. The transfer is often by shear stress acting in the window plane, but may be enhanced and perhaps even dominated by fluid flow crossing the boundary. The case of zero-time-mean fluid transport through the window has found use in experimental fluid mechanics: non-invasive measurement of wall shear stress on objects by evaluating the induced rotation in the vortex chamber. The case with the non-zero flow through the interface became the starting point in development of fluidic valves combining two otherwise mutually incompatible properties: bistability and flow turning down.

  11. Effect of induced magnetic field on peristaltic flow of a micropolar fluid in an asymmetric channel

    CERN Document Server

    Shit, G C; Ng, E Y K; 10.1002/cnm.1397

    2010-01-01

    Of concern in this paper is an investigation of peristaltic transport of a physiological fluid in an asymmetric channel under long wave length and low-Reynolds number assumptions. The flow is assumed to be incompressible, viscous, electrically conducting micropolar fluid and the effect of induced magnetic field is taken into account. Exact analytical solutions obtained for the axial velocity, microrotation component, stream line pattern, magnetic force function, axial-induced magnetic field as well as the current density distribution across the channel. The flow phenomena for the pumping characteristics, trapping and reflux are also investigated. The results presented reveal that the velocity decreases with the increase of magnetic field as well as the coupling parameter. Moreover, the trapping fluid can be eliminated by the application of an external magnetic field. Thus, the study bears the promise of important applications in physiological systems.

  12. Acute kidney injury: intravenous fluid to prevent contrast-induced AKI.

    Science.gov (United States)

    Weisbord, Steven D; Palevsky, Paul M

    2009-05-01

    Trials that compared sodium bicarbonate and sodium chloride for the prevention of contrast-induced acute kidney injury have yielded highly conflicting results. The authors of a recent meta-analysis endeavored to provide a definitive assessment of the relative efficacy of these two intravenous fluids.

  13. Bovine lactoferrin decreases cholera-toxin-induced intestinal fluid accumulation in mice by ganglioside interaction.

    Directory of Open Access Journals (Sweden)

    Fulton P Rivera

    Full Text Available Secretory diarrhea caused by cholera toxin (CT is initiated by binding of CT's B subunit (CTB to GM1-ganglioside on the surface of intestinal cells. Lactoferrin, a breast milk glycoprotein, has shown protective effect against several enteropathogens. The aims of this study were to determine the effect of bovine-lactoferrin (bLF on CT-induced intestinal fluid accumulation in mice, and the interaction between bLF and CT/CTB with the GM1-ganglioside receptor. Fluid accumulation induced by CT was evaluated in the mouse ileal loop model using 56 BALB/c mice, with and without bLF added before, after or at the same time of CT administration. The effect of bLF in the interaction of CT and CTB with GM1-ganglioside was evaluated by a GM1-enzyme-linked immunosorbent assay. bLF decreased CT-induced fluid accumulation in the ileal loop of mice. The greatest effect was when bLF was added before CT (median, 0.066 vs. 0.166 g/cm, with and without bLF respectively, p<0.01. We conclude that bLF decreases binding of CT and CTB to GM1-ganglioside, suggesting that bLF suppresses CT-induced fluid accumulation by blocking the binding of CTB to GM1-ganglioside. bLF may be effective as adjunctive therapy for treatment of cholera diarrhea.

  14. Bovine Lactoferrin Decreases Cholera-Toxin-Induced Intestinal Fluid Accumulation in Mice by Ganglioside Interaction

    Science.gov (United States)

    Rivera, Fulton P.; Medina, Anicia M.; Bezada, Sandra; Valencia, Roberto; Bernal, María; Meza, Rina; Maves, Ryan C.; Ochoa, Theresa J.

    2013-01-01

    Secretory diarrhea caused by cholera toxin (CT) is initiated by binding of CT’s B subunit (CTB) to GM1-ganglioside on the surface of intestinal cells. Lactoferrin, a breast milk glycoprotein, has shown protective effect against several enteropathogens. The aims of this study were to determine the effect of bovine-lactoferrin (bLF) on CT-induced intestinal fluid accumulation in mice, and the interaction between bLF and CT/CTB with the GM1-ganglioside receptor. Fluid accumulation induced by CT was evaluated in the mouse ileal loop model using 56 BALB/c mice, with and without bLF added before, after or at the same time of CT administration. The effect of bLF in the interaction of CT and CTB with GM1-ganglioside was evaluated by a GM1-enzyme-linked immunosorbent assay. bLF decreased CT-induced fluid accumulation in the ileal loop of mice. The greatest effect was when bLF was added before CT (median, 0.066 vs. 0.166 g/cm, with and without bLF respectively, p<0.01). We conclude that bLF decreases binding of CT and CTB to GM1-ganglioside, suggesting that bLF suppresses CT-induced fluid accumulation by blocking the binding of CTB to GM1-ganglioside. bLF may be effective as adjunctive therapy for treatment of cholera diarrhea. PMID:23580005

  15. Non-immunoglobulin fraction of human milk protects rabbits against enterotoxin-induced intestinal fluid secretion.

    OpenAIRE

    Otnaess, A B; Svennerholm, A M

    1982-01-01

    Human milk was fractionated by ammonium sulphate precipitation and column chromatography. A milk fraction depleted of secretory immunoglobulin A and with an apparent molecular weight of greater than 400,000 inhibited fluid secretion induced by cholera toxin and Escherichia coli heat-labile toxin in rabbit ileal loops.

  16. Global end-diastolic volume increases to maintain fluid responsiveness in sepsis-induced systolic dysfunction

    NARCIS (Netherlands)

    R.J. Trof (R.); I. Danad (Ibrahim); A.B.J. Groeneveld (Johan)

    2013-01-01

    textabstractBackground: Sepsis-induced cardiac dysfunction may limit fluid responsiveness and the mechanism thereof remains unclear. Since cardiac function may affect the relative value of cardiac filling pressures, such as the recommended central venous pressure (CVP), versus filling volumes in gui

  17. A model for fluid-injection-induced seismicity at the KTB, Germany

    Science.gov (United States)

    Baisch, S.; Harjes, H.-P.

    2003-01-01

    The 9.1 km deep KTB (Kontinentale Tiefbohrung, Germany) drilling hole is one of the best investigated deep-drilling sites in the world. Among other parameters, in situ measurements revealed continuous profiles of principal stresses, pore fluid pressure and fracture geometry in the vicinity of the borehole. The present study combines these parameters with hydraulic and seismicity data obtained during fluid-injection experiments conducted at the KTB to derive a conceptual model for fluid-injection-induced seismicity at the KTB. This model rests on the well constrained assumptions that (1) the crust is highly fractured with a permeable fracture network between 9 km depth and the Earth's surface and (2) the crust is in near-failure equilibrium, whereby a large number of fracture planes are under near-critical condition. During the injection experiment, the elevated pore fluid pressure remained well below the least principal stress and thus was too small to cause hydraulic opening of existing fractures. Consequently, the geometry of the fracture network was assumed to have not changed during fluid injection with induced seismicity occurring solely as a result of lowering of the effective normal stress, consistent with observed source mechanisms. The key parameter in the present model is the fracture permeability, which exhibits large spatial and directional variations. These variations are proposed to primarily control fluid migration paths and associated propagation of elevated fluid pressure during fluid injection. In contrast with common models based on isotropic fluid diffusion or spatially averaged permeability, highly permeable branches of the fracture network strongly affect the propagation of fluid pressure and prohibit the concept of a smooth `pressure front'. We find evidence that major fluid flow exists at comparatively low fluid pressure (below the critical pressure required to cause seismic failure) without being detected seismically. This might also

  18. Fingering induced by a solid sphere impact to viscous fluid

    CERN Document Server

    Katsuragi, H

    2014-01-01

    The number of splashed fingers generated by a solid projectile's impact onto a viscous liquid layer is experimentally studied. A steel sphere is dropped onto a viscous liquid pool. Then, a fingering instability occurs around the crater's rim, depending on the experimental conditions such as projectile's inertia and the viscosity of the target liquid. When the impact inertia is not sufficient, any fingering structure cannot be observed. Contrastively, if the impact inertia is too much, the random splashing is induced and the counting of fingers becomes difficult. The clear fingering instability is observable in between these two regimes. The number of fingers $N$ is counted by using high-speed video data. The scaling of $N$ is discussed on the basis of dimensionless numbers. By assuming Rayleigh-Taylor instability, scaling laws for $N$ can be derived using Reynolds number $Re$, Weber number $We$, and Froude number $Fr$. Particularly, the scaling $N=(\\rho_r Fr)^{1/4}We^{1/2}/3^{3/4}$ is obtained for the gravity...

  19. Fingering induced by a solid sphere impact to viscous fluid

    Directory of Open Access Journals (Sweden)

    Katsuragi Hiroaki

    2015-01-01

    Full Text Available The number of splashed fingers generated by a solid projectile’s impact onto a viscous liquid layer is experimentally studied. A steel sphere is dropped onto a viscous liquid pool. Then, a fingering instability occurs around the crater’s rim, depending on the experimental conditions such as projectile’s inertia and the viscosity of the target liquid. When the impact inertia is not sufficient, any fingering structure cannot be observed. Contrastively, if the impact inertia is too much, the random splashing is induced and the counting of fingers becomes difficult. The clear fingering instability is observable in between these two regimes. The number of fingers N is counted by using high-speed video data. The scaling of N is discussed on the basis of dimensionless numbers. By assuming Rayleigh-Taylor instability, scaling laws for N can be derived using Reynolds number Re, Weber number We, and Froude number Fr. Particularly, the scaling N = (ρrFr1/4We1/2/33/4 is obtained for the gravity-dominant cratering regime, where ρr is the density ratio between a projectile and a target. Although the experimental data considerably scatters, the scaling law is consistent with the global trend of the data behavior. Using one of the scaling laws, planetary nano crater’s rim structure is also evaluated.

  20. Thermodynamically Consistent Fluid Mixing in Porous Media Induced by Viscous Fingering and Channeling of Multiphase Flow

    Science.gov (United States)

    Amooie, Mohammad Amin; Soltanian, Mohammad Reza; Moortgat, Joachim

    2016-11-01

    Fluid mixing and its interplay with viscous fingering as well as flow channeling through heterogeneous media have been traditionally studied for fully (im)miscible conditions in which a (two-) single-phase system is represented by two components, e.g. a solvent and a solute, with (zero) infinite mutual solubility. However, many subsurface problems, e.g. gas injection/migration in hydrocarbon reservoirs, involve multiple species transfer. Multicomponent fluid properties behave non-linearly, through an equation of state, as a function of temperature, pressure, and compositions. Depending on the minimum miscibility pressure, a two-phase region with finite, non-zero mutual solubility may develop, e.g. in a partially-miscible system. Here we study mixing of fluids with partial mutual solubility, induced by viscous flow fingering, channeling, and species transport within and between phases. We uncover non-linear mixing dynamics of a finite-size slug of a less viscous fluid attenuated by a carrier fluid during rectilinear displacement. We perform accurate numerical simulations that are thermodynamically-consistent to capture fingering patterns and complex phase behavior of mixtures. The results provide a broad perspective into how multiphase flow can alter fluid mixing in porous media.

  1. Effect of immunomodulator pyrimethamine and cimetidine on immunosuppression induced by burn blister fluid.

    Science.gov (United States)

    Gharegozloo, Behnaz; Hassan, Zuhair M; K Ardestani, Sussan; Tavassoli, Nasser

    2004-09-01

    Despite recent advances in burn wound management, sepsis remains the main cause of death in patients resuscitated after major thermal injury. Increased susceptibility to infections has been related to severe suppression of the immune system.The aim of this study was to induce immune suppression with blister fluid injection, and to modulate immune response by use of cimetidine and pyrimethamine in animal model.Male Balb/c mice were injected with blister fluid intrapritoneally (ip). Fluids were collected from parital-thickness burn blisters and then the delayed type hypersensitivity (DTH) to sheep red blood cell (SRBC) and the effects of different doses of immunomodulators (Cimetidine and Pyrimethamine) on this response were quantitated.A marked suppression of DTH was observed in mice injected with blister fluid. Pyrimethamine and Cimetidine at all three doses caused a significant enhancement of DTH response to SRBC compared with blister fluid injected in control group.This finding represents evidence of a host defense defect within the burn wound and also indicates the blister fluid exhibit immunosuppressor factor that can modulate with immunomadulatory drugs like cimetidine and pyrimethamine.

  2. Laboratory study of fluid viscosity induced ultrasonic velocity dispersion in reservoir sandstones

    Science.gov (United States)

    He, Tao; Zou, Chang-Chun; Pei, Fa-Gen; Ren, Ke-Ying; Kong, Fan-Da; Shi, Ge

    2010-06-01

    Ultrasonic velocities of a set of saturated sandstone samples were measured at simulated in-situ pressures in the laboratory. The samples were obtained from the W formation of the WXS Depression and covered low to nearly high porosity and permeability ranges. The brine and four different density oils were used as pore fluids, which provided a good chance to investigate fluid viscosity-induced velocity dispersion. The analysis of experimental observations of velocity dispersion indicates that (1) the Biot model can explain most of the small discrepancy (about 2-3%) between ultrasonic measurements and zero frequency Gassmann predictions for high porosity and permeability samples saturated by all the fluids used in this experiment and is also valid for medium porosity and permeability samples saturated with low viscosity fluids (less than approximately 3 mP·S) and (2) the squirt flow mechanism dominates the low to medium porosity and permeability samples when fluid viscosity increases and produces large velocity dispersions as high as about 8%. The microfracture aspect ratios were also estimated for the reservoir sandstones and applied to calculate the characteristic frequency of the squirt flow model, above which the Gassmann’ s assumptions are violated and the measured high frequency velocities cannot be directly used for Gassmann’s fluid replacement at the exploration seismic frequency band for W formation sandstones.

  3. INCREASED CONCENTRATION OF NITRITE IN SYNOVIAL FLUID AND SERUM SAMPLES IN STEROID INDUCED FEMORAL HEAD NECROSIS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    To investigate the role of nitric oxide (NO) in steroid-induced femoral head necrosis, NO production was measured indirectly as nitrite in serum and synovial fluid samples from patients with steroid-induced femoral head necrosis together with serum samples from healthy volunteers matched for age and sex. The results showed that:① serum nitrite concentration in patients with femoral head necrosis were significantly lower than that in controls (P<0.001); ② nitrite level of synovial fluid was markedly higher than that of serum. In addition, there was a positive correlation between them (r=0.378,P<0.05). We reach the conclusion:① NO is synthesized by synovium and chondrocytes; ② the decreased NO concentration in serum suggests a protective role in steroid-induced femoral head necrosis.

  4. Seismicity on Basement Faults Induced by Simultaneous Fluid Injection-Extraction

    Science.gov (United States)

    Chang, Kyung Won; Segall, Paul

    2016-08-01

    Large-scale carbon dioxide (CO2) injection into geological formations increases pore pressure, potentially inducing seismicity on critically stressed faults by reducing the effective normal stress. In addition, poroelastic expansion of the reservoir alters stresses, both within and around the formation, which may trigger earthquakes without direct pore-pressure diffusion. One possible solution to mitigate injection-induced earthquakes is to simultaneously extract pre-existing pore fluids from the target reservoir. To examine the feasibility of the injection-extraction strategy, we compute the spatiotemporal change in Coulomb stress on basement normal faults, including: (1) the change in poroelastic stresses Δ τ _s+fΔ σ _n, where Δ τ _s and Δ σ _n are changes in shear and normal stress. respectively, and (2) the change in pore-pressure fΔ p. Using the model of (J. Geophys. Res. Solid Earth 99(B2):2601-2618, 1994), we estimate the seismicity rate on basement fault zones. Fluid extraction reduces direct pore-pressure diffusion into conductive faults, generally reducing the risk of induced seismicity. Limited diffusion into/from sealing faults results in negligible pore pressure changes within them. However, fluid extraction can cause enhanced seismicity rates on deep normal faults near the injector as well as shallow normal faults near the producer by poroelastic stressing. Changes in seismicity rate driven by poroelastic response to fluid injection-extraction depends on fault geometry, well operations, and the background stressing rate.

  5. Workshop on induced Seismicity due to fluid injection/production from Energy-Related Applications

    Energy Technology Data Exchange (ETDEWEB)

    Majer, E.L.; Asanuma, Hiroshi; Rueter, Horst; Stump, Brian; Segall, Paul; Zoback, Mark; Nelson, Jim; Frohlich, Cliff; Rutledge, Jim; Gritto, Roland; Baria, Roy; Hickman, Steve; McGarr, Art; Ellsworth, Bill; Lockner, Dave; Oppenheimer, David; Henning, Peter; Rosca, Anca; Hornby, Brian; Wang, Herb; Beeler, Nick; Ghassemi, Ahmad; Walters, Mark; Robertson-Tait, Ann; Dracos, Peter; Fehler, Mike; Abou-Sayed, Ahmed; Ake, Jon; Vorobiev, Oleg; Julian, Bruce

    2011-04-01

    Geothermal energy, carbon sequestration, and enhanced oil and gas recovery have a clear role in U.S. energy policy, both in securing cost-effective energy and reducing atmospheric CO{sub 2} accumulations. Recent publicity surrounding induced seismicity at several geothermal and oil and gas sites points out the need to develop improved standards and practices to avoid issues that may unduly inhibit or stop the above technologies from fulfilling their full potential. It is critical that policy makers and the general community be assured that EGS, CO{sub 2} sequestration, enhanced oil/gas recovery, and other technologies relying on fluid injections, will be designed to reduce induced seismicity to an acceptable level, and be developed in a safe and cost-effective manner. Induced seismicity is not new - it has occurred as part of many different energy and industrial applications (reservoir impoundment, mining, oil recovery, construction, waste disposal, conventional geothermal). With proper study/research and engineering controls, induced seismicity should eventually allow safe and cost-effective implementation of any of these technologies. In addition, microseismicity is now being used as a remote sensing tool for understanding and measuring the success of injecting fluid into the subsurface in a variety of applications, including the enhancement of formation permeability through fracture creation/reactivation, tracking fluid migration and storage, and physics associated with stress redistribution. This potential problem was envisaged in 2004 following observed seismicity at several EGS sites, a study was implemented by DOE to produce a white paper and a protocol (Majer et al 2008) to help potential investors. Recently, however, there have been a significant number of adverse comments by the press regarding induced seismicity which could adversely affect the development of the energy sector in the USA. Therefore, in order to identify critical technology and research

  6. Interface profile evolution between binary immiscible fluids induced by high magnetic field gradients

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A mechanical analysis is done to find the evolution of the interface profile between binary immiscible fluids induced by a three-dimensional orthogonal magnetic field gradient.In the experiments,the changes of the interface profile between four groups of binary immiscible fluids are investigated under the same horizontal magnetic field gradients.The binary immiscible fluids are made of benzene and other liquids,like CuSO4,Fecl3,FeSO4 or Cucl2 aqueous solutions.In addition,the interface profile between the benzene and CuSO4 aqueous solution is examined under different horizontal magnetic field gradients.The experimental results are consistent with the theoretical analysis.This study explains the enhanced Moses effect from a mechanics standpoint.Furthermore,a new method for susceptibility measurement is proposed based on this enhanced Moses effect.

  7. Temperature gradient-induced fluid pumping inside a single-wall carbon nanotube: A non-equilibrium molecular dynamics study

    Science.gov (United States)

    Faraji, Fahim; Rajabpour, Ali

    2016-09-01

    In this paper we investigate the fluid transport inside a single-wall carbon nanotube induced by a temperature gradient along the tube length, focusing on the effect of fluid-wall interaction strength. It is found that the fluid moves from the hot side of the nanotube towards the cold side. By increasing the fluid-wall interaction strength, the fluid volumetric flux assumes a maximum, increases, and then decreases. Fluid transport is pressure-driven in weak interactions; in contrast, in strong interactions, the fluid is broken into two parts in the radial direction. Fluid transport in the central regions of the tube is pressure-driven, while it is surface-driven in the areas close to the wall.

  8. Wind-induced vibration control of Hefei TV tower with fluid viscous damper

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhiqiang; Aiqun LI; Jianping HE; Jianlei WANG

    2009-01-01

    The Hefei TV tower is taken as an analytical case to examine the control method with a fluid viscous damper under wind load fluctuation. Firstly, according to the random vibration theory, the effect of fluctuating wind on the tower can be modeled as a 19-dimensional correlated random process, and the wind-induced vibration analysis of the tower subjected to dynamic wind load was further obtained. On the basis of the others' works, a bi-model dynamic model is proposed. Finally, a dynamic model is proposed to study the wind-induced vibration control analysis using viscous fluid dampers, and the optimal damping coefficient is obtained regarding the wind-induced response of the upper turret as optimization objectives. Analysis results show that the maximum peak response of the tower under dynamic wind load is far beyond the allowable range of the code. The wind-induced responses and the wind vibration input energy of the tower are decreased greatly by using a fluid viscous damper, and the peak acceleration responses of the upper turret is reduced by 43.4%.

  9. Schlieren High Speed Imaging on Fluid Flow in Liquid Induced by Plasma-driven Interfacial Forces

    Science.gov (United States)

    Lai, Janis; Foster, John

    2016-10-01

    Effective plasma-based water purification depends heavily on the transport of plasma-derived reactive species from the plasma into the liquid. Plasma interactions at the liquid-gas boundary are known to drive circulation in the bulk liquid. This forced circulation is not well understood. A 2-D plasma- in-liquid water apparatus is currently being investigated as a means to study the plasma-liquid interface to understand not only reactive species flows but to also understand plasma- driven fluid dynamic effects in the bulk fluid. Using Schlieren high speed imaging, plasma-induced density gradients near the interfacial region and into the bulk solution are measured to investigate the nature of these interfacial forces. Plasma-induced flow was also measured using particle imaging velocimetry. NSF CBET 1336375 and DOE DE-SC0001939.

  10. Femtosecond Raman induced polarization spectroscopy studies of coherent rotational dynamics in molecular fluids

    Energy Technology Data Exchange (ETDEWEB)

    Morgen, Michael Mark [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1997-05-01

    We develop a polarization-sensitive femtosecond pump probe technique, Raman induced polarization spectroscopy (RIPS), to study coherent rotation in molecular fluids. By observing the collisional dephasing of the coherently prepared rotational states, we are able to extract information concerning the effects of molecular interactions on the rotational motion. The technique is quite sensitive because of the zero background detection method, and is also versatile due to its nonresonant nature.

  11. Some Factors Controlling the Seismic Hazard due to Earthquakes Induced by Fluid Injection at Depth

    Science.gov (United States)

    McGarr, A.

    2012-12-01

    The maximum seismic moment (or moment magnitude) is an important measure of the seismic hazard associated with earthquakes induced by deep fluid injection. Although it would be advantageous to be able to predict the induced earthquake outcome, including the maximum seismic moment, of a specified fluid injection project in advance, this capability has, to date, proved to be elusive because the geomechanical and hydrological factors that control the seismic response to injection are too poorly understood. Fortunately, the vast majority of activities involving the injection of fluids into deep aquifers do not cause earthquakes that are large enough to be of any consequence. There have been, however, significant exceptions during the past 50 years, starting with the earthquakes induced by injection of wastewater at the Rocky Mountain Arsenal Well, during the 1960s, that caused extensive damage in the Denver, CO, area. Results from numerous case histories of earthquakes induced by injection activities, including wastewater disposal at depth and the development of enhanced geothermal systems, suggest that it may be feasible to estimate bounds on maximum magnitudes based on the volume of injected liquid. For these cases, volumes of injected liquid ranged from approximately 11.5 thousand to 5 million cubic meters and resulted in main shock moment magnitudes from 3.4 to 5.3. Because the maximum seismic moment appears to be linearly proportional to the total volume of injected fluid, this upper bound is expected to increase with time as long as a given injection well remains active. For example, in the Raton Basin, southern Colorado and northern New Mexico, natural gas is produced from an extensive coal bed methane field. The deep injection of wastewater associated with this gas production has induced a sequence of earthquakes starting in August 2001, shortly after the beginning of major injection activities. Most of this seismicity defines a northeast striking plane dipping

  12. ac-Field-induced fluid pumping in microsystems with asymmetric temperature gradients.

    Science.gov (United States)

    Holtappels, Moritz; Stubbe, Marco; Gimsa, Jan

    2009-02-01

    We present two different designs of electrohydrodynamic micropumps for microfluidic systems. The micropumps have no movable parts, and their simple design allows for fabrication by microsystems technology. The pumps are operated by ac voltages from 1 to 60 V and were tested with aqueous solutions in the conductivity range of 1-112 mS m(-1). The pump effect is induced by an ac electric field across a fluid medium with an inhomogeneous temperature distribution. It is constant over a wide range of the ac field frequency with a conductivity-dependent drop-off at high frequencies. The temperature-dependent conductivity and permittivity distributions in the fluid induce space charges that interact with the electric field and induce fluid motion. The temperature distribution can be generated either by Joule heating in the medium or by external heating. We present experimental results obtained with two prototypes featuring Joule heating and external heating by a heating filament. Experimental and numerical results are compared with an analytical model.

  13. Open channel flows of magnetic fluid induced by traveling magnetic field

    Science.gov (United States)

    Kuwahara, Takuya; Okubo, Masaaki; Yamane, Ryuichiro

    A theoretical analysis is made on laminar open channel flows of magnetic fluid induced by a non uniform traveling magnetic field which is applied with a stator of a single-sided linear induction motor. The induced flows are mainly in the direction opposite to the traveling direction of the magnetic field and in proportion to the phase velocity of the magnetic field. The velocity profiles are greatly affected by dimensionless wave number of the magnetic field. Near the bottom of the channel, the theoretical velocity distributions agree well with experimental ones which are measured with a laser optical fiber velocity sensor. However, the experimental velocity distributions become larger near the free surface.

  14. Remote monitoring of the mechanical instability induced by fluid substitution and water weakening in the laboratory

    Science.gov (United States)

    Dautriat, Jeremie; Sarout, Joel; David, Christian; Bertauld, Delphine; Macault, Romaric

    2016-12-01

    We studied the effect of fluid injection on the mechanical behaviour of the poorly consolidated and layered Sherwood sandstone under varying stresses, with micro-seismic (MS) monitoring. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties, derive the ultrasonic signature of the saturation front for each fluid, and the potential development of damage. To this end, the specimens were instrumented with 16 ultrasonic P-wave transducers used for both passive and active monitoring during loading and fluid injection. A first set of injection tests in hydrostatic conditions, using either water or inert oil, has been performed on samples subjected to low confining pressure. Water invasion in the pore space induces a significant decrease of the P-wave velocity, whereas oil invasion shows a velocity increase. The velocity decrease associated with water injection is analysed in terms of attenuation mechanisms and corresponding critical frequencies. A second series of injection tests with the same fluids has been performed during creep tests on critically-loaded samples. The development of mechanical instability inducing micro-seismic activity is observed only when water is injected into the sample. The recorded micro-seismic events are spatially and temporally located thanks to the dedicated velocity models accounting for the initially homogeneous sample anisotropy and for the heterogeneous velocity field associated with fluid migration within the sample. The consistency between the relocated clusters of events and the final damage pattern is verified thanks to X-ray computed tomography images of the samples taken post-mortem.

  15. Computational Modeling of Cephalad Fluid Shift for Application to Microgravity-Induced Visual Impairment

    Science.gov (United States)

    Nelson, Emily S.; Best, Lauren M.; Myers, Jerry G.; Mulugeta, Lealem

    2013-01-01

    An improved understanding of spaceflight-induced ocular pathology, including the loss of visual acuity, globe flattening, optic disk edema and distension of the optic nerve and optic nerve sheath, is of keen interest to space medicine. Cephalad fluid shift causes a profoundly altered distribution of fluid within the compartments of the head and body, and may indirectly generate phenomena that are biomechanically relevant to visual function, such as choroidal engorgement, compromised drainage of blood and cerebrospinal fluid (CSF), and altered translaminar pressure gradient posterior to the eye. The experimental body of evidence with respect to the consequences of fluid shift has not yet been able to provide a definitive picture of the sequence of events. On earth, elevated intracranial pressure (ICP) is associated with idiopathic intracranial hypertension (IIH), which can produce ocular pathologies that look similar to those seen in some astronauts returning from long-duration flight. However, the clinically observable features of the Visual Impairment and Intracranial Pressure (VIIP) syndrome in space and IIH on earth are not entirely consistent. Moreover, there are at present no experimental measurements of ICP in microgravity. By its very nature, physiological measurements in spaceflight are sparse, and the space environment does not lend itself to well-controlled experiments. In the absence of such data, numerical modeling can play a role in the investigation of biomechanical causal pathways that are suspected of involvement in VIIP. In this work, we describe the conceptual framework for modeling the altered compartmental fluid distribution that represents an equilibrium fluid distribution resulting from the loss of hydrostatic pressure gradient.

  16. Comparison of rotordynamic fluid forces in axial inducers and centrifugal turbopump impellers

    Science.gov (United States)

    d'Agostino, Luca

    2016-05-01

    The paper illustrates and compares the results of the experimental campaigns carried out in the Cavitating Pump Rotordynamic Test Facility (CPRTF) at Alta, Italy, under ESA funding for the characterization of the lateral rotordynamic fluid forces acting on high-head axial inducers and centrifugal turbopump impellers for space propulsion applications. The configurations presented here refer to a three-bladed tapered-hub, variable-pitch, inducer (DAPROT3) and a single-stage centrifugal pump (VAMPIRE) with vaneless diffuser and single spiral volute. Both the centrifugal pump and the inducer have been designed by means of reduced order models specifically developed by the author and his collaborators for the geometric definition and performance prediction of this kind of hydraulic turbomachinery. Continuous spectra of the rotordynamic forces acting on the impellers as functions of the whirl frequency have been obtained by means of the novel technique recently developed and demonstrated at Alta. The influence of the rotor whirl motion, flow rate, cavitating conditions, and liquid temperature (thermal cavitation effects) on the rotordynamic fluid forces is illustrated and the observed differences in their behavior in axial inducers and centrifugal turbpumps are discussed and interpreted in the light of the outcome of recent cavitation visualization experiments carried out by the Chemical Propulsion Team at Alta.

  17. Observation and modeling of the storm-induced fluid mud dynamics in a muddy-estuarine navigational channel

    Science.gov (United States)

    Wan, Yuanyang; Roelvink, Dano; Li, Weihua; Qi, Dingman; Gu, Fengfeng

    2014-07-01

    Observations of storm-induced fluid mud dynamics have been conducted at the North Passage deepwater navigational channel (DNC) of the Yangtze Estuary in October to December 2010, during the occurrence of a cold-air front. The measurement data reveal that just after the critical wind wave event, a large amount of fine sediment was trapped in a state of fluid mud along the channel. The observed thickness of the fluid mud was up to about 1-5 m, which caused some significant economic and safety problems for shipping traffic in the Yangtze Delta area. The mechanisms and transport processes of the storm-induced fluid mud are analyzed and presented from the angles of both process-oriented and engineering-oriented methods. With the help of hydrodynamics and wave modeling, it could be inferred that the behavior of the storm-induced fluid mud event mainly depends on the overall hydrodynamic regimes and the exchanges of sediment, which is released by storm-wave agitation from adjacent tidal flats. These sediments are accumulated as fluid mud, and subsequently oscillate and persist at those locations with weaker longitudinal residuals in the river- and tide-dominated estuary. In addition, the downslope transport of fluid mud is also thought to have stimulated and worsened the fluid mud event observed in this study. Our modeling results and observations demonstrate that: (1) the transport of fluid mud is an advective phenomenon determining the central position of fluid mud layer along the channel, and it's also a tidal energy influenced phenomenon controlling the erosion and accumulation of fluid mud; and (2) both suspended particulate matter availability and local residual flow regime are of critical importance in determining the trapping probability of sediment and the occurrence of fluid mud.

  18. Waves induced by a submerged moving dipole in a two-layer fluid of finite depth

    Institute of Scientific and Technical Information of China (English)

    Gang Wei; Dongqiang Lu; Shiqiang Dai

    2005-01-01

    The waves induced by a moving dipole in a twofluid system are analytically and experimentally investigated.The velocity potential of a dipole moving horizontally in the lower layer of a two-layer fluid with finite depth is derived by superposing Green's functions of sources (or sinks). The far-field waves are studied by using the method of stationary phase. The effects of two resulting modes, i.e. the surfaceand internal-wave modes, on both the surface divergence field and the interfacial elevation are analyzed. A laboratory study on the internal waves generated by a moving sphere in a two-layer fluid is conducted in a towing tank under the same conditions as in the theoretical approach. The qualitative consistency between the present theory and the laboratory study is examined and confirmed.

  19. Allergen-induced increase of eosinophil cationic protein in nasal lavage fluid

    DEFF Research Database (Denmark)

    Bisgaard, H; Grønborg, H; Mygind, N;

    1990-01-01

    It was our aim to study the effect of nasal allergen provocation on the concentration of eosinophil cationic protein (ECP) in nasal lavage fluid, with and without glucocorticoid pretreatment. Twenty grass-pollen sensitive volunteers were provoked outside the pollen season on 2 consecutive days...... untreated, prechallenge noses was 400 micrograms/L. (3) The ECP level did not increase during the early phase response. (4) There was a late occurring increase in the ECP concentration (6 to 24 hours). (5) This increase was completely inhibited by budesonide pretreatment. (6) The glucocorticoid therapy also...... reduced the prechallenge ECP concentration. In conclusion, allergen provocation in the nose results in a late occurring increase of ECP in nasal lavage fluid, and one of the therapeutic effects of topical glucocorticoid therapy may be an inhibition of the allergen-induced increase of this cytotoxic...

  20. Flow-Induced Vibration of A Nonlinearly Restrained Curved Pipe Conveying Fluid

    Institute of Scientific and Technical Information of China (English)

    王琳; 倪樵; 黄玉盈

    2004-01-01

    Investigated in this study is the flow-induced vibration of a nonlinearly restrained curved pipe conveying fluid. The nonlinear equation of motion is derived by equilibrium of forces on microelement of the system under consideration. The spatial coordinate of the system is discretized by DQM (differential quadrature method). On the basis of the boundary conditions, the dynamic equation is solved by the Newton-Raphson iteration method. The numerical solutions reveal several complex dynamic motions for the variation of the fluid velocity parameter, such as limit cycle motion, buckling and so on. The result obtained also shows that the sub parameter regions corresponding to the several motions may change with the variation of some parameters of the curved pipe. The present study supplies a new reference for investigating the nonlinear dynamic response of some other structures.

  1. Simulation of fluid flow induced by opposing ac magnetic fields in a continuous casting mold

    Energy Technology Data Exchange (ETDEWEB)

    Chang, F.C.; Hull, J.R. [Argonne National Lab., IL (United States); Beitelman, L. [J. Mulcahy Enterprises, Whitby, ON (Canada)

    1995-07-01

    A numerical simulation was performed for a novel electromagnetic stirring system employing two rotating magnetic fields. The system controls stirring flow in the meniscus region of a continuous casting mold independently from the stirring induced within the remaining volume of the mold by a main electromagnetic stirrer (M-EMS). This control is achieved by applying to the meniscus region an auxiliary electromagnetic field whose direction of rotation is opposite to that of the main magnetic field produced by the M-EMS. The model computes values and spatial distributions of electromagnetic parameters and fluid flow in the stirred pools of mercury in cylindrical and square geometries. Also predicted are the relationships between electromagnetics and fluid flows pertinent to a dynamic equilibrium of the opposing stirring swirls in the meniscus region. Results of the numerical simulation compared well with measurements obtained from experiments with mercury pools.

  2. NONLINEAR FLUID DAMPING IN STRUCTURE-WAKE OSCILLATORS IN MODELING VORTEX-INDUCED VIBRATIONS

    Institute of Scientific and Technical Information of China (English)

    LIN Li-ming; LING Guo-can; WU Ying-xiang; ZENG Xiao-hui

    2009-01-01

    A Nonlinear Fluid Damping(NFD)in the form of the square-velocity is applied in the response analysis of Vortex-Induced Vibrations(VIV).Its nonlinear hydrodynamic effects on the coupled wake and structure oscillators are investigated.A comparison between the coupled systems with the linear and nonlinear fluid dampings and experiments shows that the NFD model can well describe response characteristics,such as the amplification of body displacement at lock-in and frequency lock-in,both at high and low mass ratios.Particularly,the predicted peak amplitude of the body in the Griffin plot is in good agreement with experimental data and empirical equation,indicating the significant effect of the NFD on the structure motion.

  3. Fluid and solid mechanics in a poroelastic network induced by ultrasound.

    Science.gov (United States)

    Wang, Peng; Olbricht, William L

    2011-01-04

    We made a theoretical analysis on the fluid and solid mechanics in a poroelastic medium induced by low-power ultrasound. Using a perturbative approach, we were able to linearize the governing equations and obtain analytical solutions. We found that ultrasound could propagate in the medium as a mechanical wave, but would dissipate due to frictional forces between the fluid and the solid phase. The amplitude of the wave depends on the ultrasonic power input. We applied this model to the problem of drug delivery to soft biological tissues by low-power ultrasound and proposed a mechanism for enhanced drug penetration. We have also found the coexistence of two acoustic waves under certain circumstances and pointed out the importance of very accurate experimental determination of the high-frequency properties of brain tissue.

  4. Vacuolar-ATPase (V-ATPase) Mediates Progesterone-Induced Uterine Fluid Acidification in Rats.

    Science.gov (United States)

    Karim, Kamarulzaman; Giribabu, Nelli; Muniandy, Sekaran; Salleh, Naguib

    2016-04-01

    We hypothesized that progesterone-induced decrease in uterine fluid pH involves V-ATPase. In this study, expression and functional activity of V-ATPase in uterus were investigated under progesterone influence. Ovariectomized adult female rats received subcutaneous injection of estradiol-17β (1 µg/kg/day) or progesterone (20 mg/kg/day) for 3 days or 3 days estradiol-17β followed by 3 days vehicle, progesterone, or estradiol-17β plus progesterone. Mifepristone, a progesterone receptor blocker, was concomitantly given to the rats which received progesterone. A day after last injection, rate of uterine fluid secretion, its HCO3 (-) concentration, and pH were determined via in vivo uterine perfusion in rats under anesthesia. V-ATPase inhibitor, bafilomycin, was introduced into the perfusion buffer, and changes in these parameters were observed. Expression of V-ATPase A1 and B1/2 proteins and mRNAs in uterus were quantified by Western blotting and real-time PCR, respectively. Distribution of these proteins was observed by immunohistochemistry. Our findings showed that under progesterone influence, uterine fluid secretion rate, HCO3 (-) concentration, and pH were significantly reduced. Administration of bafilomycin did not cause significant changes in fluid secretion rate; however, HCO3 (-) concentration and pH were significantly elevated. In parallel with these changes, expression of V-ATPase A1 and B1/2 proteins and mRNAs were significantly increased with these proteins highly distributed in uterine luminal and glandular epithelia. In conclusion, increased expression and functional activity of V-ATPase were most likely responsible for the decreased in uterine fluid pH observed under progesterone influence.

  5. A novel method for analyzing seismic energy loss associated with wave-induced fluid flow

    Science.gov (United States)

    Solazzi, Santiago G.; Germán Rubino, J.; Müller, Tobias M.; Milani, Marco; Guarracino, Luis; Holliger, Klaus

    2014-05-01

    Whenever a seismic wave propagates through a fluid saturated porous rock that contains heterogeneities in the mesoscopic scale, that is, heterogeneities larger than the typical pore size but smaller than the predominant wavelengths, local gradients in the pore-fluid pressure arise. These pressure gradients, which are due to the uneven response of the heterogeneities to the stress applied by the passing seismic wavefield, induce viscous fluid flow and energy dissipation. Consequently, seismic waves tend to be strongly attenuated and dispersed in this kind of media. This attenuation mechanism scales with the compressibility contrast between heterogeneities and the background. Correspondingly, environments characterized by patchy saturation as well as fractured media represent two prominent scenarios where seismic attenuation due to wave-induced fluid flow is expected to be the predominant energy dissipation mechanism. Numerical oscillatory compressibility and shear tests based on the quasistatic poroelasticity equations provide an effective means to compute equivalent viscoelastic moduli for representative rock samples of the heterogeneous media under study. Approaches of this type rely on the existence of a dynamic-equivalent medium, that is, the heterogeneous porous rock is represented by an equivalent homogeneous viscoelastic solid that exhibits an overall response similar to that of the original heterogeneous porous sample. This methodology allows for extracting the equivalent seismic attenuation and phase velocity of the sample, but fails to provide any information with regard to the underlying physical processes. In this work, we present a novel approach based on the quantification of the energy loss taking place in the interior of the considered heterogeneous rock sample. To this end, we first determine the spatial distribution of the energy dissipation in response to the applied oscillatory stresses. Next, we quantify the total dissipated energy as well as

  6. On the pressure and stress singularities induced by steady flows of incompressible viscous fluids

    Institute of Scientific and Technical Information of China (English)

    G.B.Sinclair; X.Chi; T.I-P.Shih

    2009-01-01

    Design for structural integrity requires an appreciation of where stress singularities can occur in structural configurations. While there is a rich literature devoted to the identification of such singular behavior in solid mechanics, to date there has been relatively little explicit identification of stress singularities caused by fluid flows. In this study, stress and pressure singularities induced by steady flows of viscous incompressible fluids are asymptotically identified. This is done by taking advantage of an earlier result that the Navier-Stokes equations are locally governed by Stokes flow in angular corners. Findings for power singularities are confirmed by developing and using an analogy with solid mechanics. This analogy also facilitates the identification of flow-induced log singularities. Both types of singularity are further confirmed for two global configurations by applying convergence-divergence checks to numerical results. Even though these flow-induced stress singularities are analogous to singularities in solid mechanics, they nonetheless render a number of structural configurations singular that were not previously appreciated as such from identifications within solid mechanics alone.

  7. Peritoneal fluid modulates the sperm acrosomal exocytosis induced by N-acetylglucosaminyl neoglycoprotein

    Directory of Open Access Journals (Sweden)

    E.P. Passos

    1999-01-01

    Full Text Available The effect of peritoneal fluid (PF on the human sperm acrosome reaction (AR was tested. Sperm was pre-incubated with PF and the AR was induced by calcium ionophore A23187 and a neoglycoprotein bearing N-acetylglycosamine residues (NGP. The AR induced by calcium ionophore was inhibited 40% by PF from controls (PFc and 50% by PF from the endometriosis (PFe group, but not by PF from infertile patients without endometriosis (PFi. No significant differences were found in the spontaneous AR. When the AR was induced by NGP, pre-incubation with PFc reduced (60% the percentage of AR, while PFe and PFi caused no significant differences. The average rates of acrosome reactions obtained in control, NGP- and ionophore-treated sperm showed that NGP-induced exocytosis differed significantly between the PFc (11% and PFe/PFi groups (17%, and the ionophore-induced AR was higher for PFi (33% than PFc/PFe (25%. The incidence of the NGP-induced AR was reduced in the first hour of pre-incubation with PFc and remained nearly constant throughout 4 h of incubation. The present data indicate that PF possesses a protective factor which prevents premature AR.

  8. Molecular dissociation and shock-induced cooling in fluid nitrogen at high densities and temperatures

    Science.gov (United States)

    Radousky, H. B.; Nellis, W. J.; Ross, M.; Hamilton, D. C.; Mitchell, A. C.

    1986-01-01

    Radiative temperatures and electrical conductivities were measured for fluid nitrogen compressed dynamically to pressures of 18-90 GPa, temperatures of 4000-14,000 K, and densities of 2-3 g/cu cm. The data show a continuous phase transition above 30 GPa shock pressure and confirm that (delta-P/delta-T)v is less than 0, as indicated previously by Hugoniot equation-of-state experiments. The first observation of shock-induced cooling is also reported. The data are interpreted in terms of molecular dissociation, and the concentration of dissociated molecules is calculated as a function of density and temperature.

  9. Inspiration of induced magnetic field on nano hyperbolic tangent fluid in a curved channel

    Science.gov (United States)

    Nadeem, S.; Shahzadi, Iqra

    2016-01-01

    In this research, peristaltic flow of nano hyperbolic tangent fluid is investigated in a curved channel. The model used for the nanofluid includes the effects of thermophoresis and Brownian motion. The resulting equations are assembled in wave frame of reference under the effects of curvature. Influence of induced magnetic field is studied. Long wavelength and low Reynolds number supposition are treated. The travelling wave front of peristaltic flow is chosen sinusoidal (extension /reduction). Analytical solutions are computed by homotopy perturbation method. Results of substantial quantities are explained with particular attention to rheological aspects.

  10. Inspiration of induced magnetic field on nano hyperbolic tangent fluid in a curved channel

    Directory of Open Access Journals (Sweden)

    S. Nadeem

    2016-01-01

    Full Text Available In this research, peristaltic flow of nano hyperbolic tangent fluid is investigated in a curved channel. The model used for the nanofluid includes the effects of thermophoresis and Brownian motion. The resulting equations are assembled in wave frame of reference under the effects of curvature. Influence of induced magnetic field is studied. Long wavelength and low Reynolds number supposition are treated. The travelling wave front of peristaltic flow is chosen sinusoidal (extension /reduction. Analytical solutions are computed by homotopy perturbation method. Results of substantial quantities are explained with particular attention to rheological aspects.

  11. On The Analysis of Labyrinth Seal Flow Induced Vibration by Oscillating Fluid Mechanics Method

    Institute of Scientific and Technical Information of China (English)

    ChenZuoyi; JingYouhao; 等

    1994-01-01

    A numerical model and a solution method to analyze the labyrinth seal flow induced vibration by Oscillating Fluid Mechanics Method(OFMM) are presented in this paper,including the basic equations and solution procedure to determine the oscillating velocity,pressure and the dynamic characteristic coefficients of Labyrinth seal such as the stiffness coefficients and damping coefficients.The results show that this method has the advantages of both less time consuming and high accuracy.In addition it can be applied to the field diagnosis of the vibration of the axis of turbomachinery system.

  12. Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan; Adinolfi, Pierangelo

    2004-03-26

    OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by

  13. Wave propagation and induced steady streaming in viscous fluid contained in a prestressed viscoelastic tube

    Science.gov (United States)

    Ma, Ye; Ng, Chiu-On

    2009-05-01

    The oscillatory and time-mean motions induced by a propagating wave of small amplitude through a viscous incompressible fluid contained in a prestressed and viscoelastic (modeled as a Voigt material) tube are studied by a perturbation analysis based on equations of motion in the Lagrangian system. The classical problem of oscillatory viscous flow in a flexible tube is re-examined in the contexts of blood flow in arteries or pulmonary gas flow in airways. The wave kinematics and dynamics, including wavenumber, wave attenuation, velocity, and stress fields, are found as analytical functions of the wall and fluid properties, prestress, and the Womersley number for the cases of a free or tethered tube. On extending the analysis to the second order in terms of the small wave steepness, it is shown that the time-mean motion of the viscoelastic tube with sufficient strength is short lived and dies out quickly as a limit of finite deformation is approached. Once the tube has attained its steady deformation, the steady streaming in the fluid can be solved analytically. Results are generated to illustrate the combined effects on the first-order oscillatory flow and the second-order steady streaming due to elasticity, viscosity, and initial stresses of the wall. The present model as applied to blood flow in arteries and gas flow in pulmonary airways during high-frequency ventilation is examined in detail through comparison with models in the literature.

  14. A model of posttraumatic epilepsy induced by lateral fluid-percussion brain injury in rats.

    Science.gov (United States)

    Kharatishvili, I; Nissinen, J P; McIntosh, T K; Pitkänen, A

    2006-06-30

    Although traumatic brain injury is a major cause of symptomatic epilepsy, the mechanism by which it leads to recurrent seizures is unknown. An animal model of posttraumatic epilepsy that reliably reproduces the clinical sequelae of human traumatic brain injury is essential to identify the molecular and cellular substrates of posttraumatic epileptogenesis, and perform preclinical screening of new antiepileptogenic compounds. We studied the electrophysiologic, behavioral, and structural features of posttraumatic epilepsy induced by severe, non-penetrating lateral fluid-percussion brain injury in rats. Data from two independent experiments indicated that 43% to 50% of injured animals developed epilepsy, with a latency period between 7 weeks to 1 year. Mean seizure frequency was 0.3+/-0.2 seizures per day and mean seizure duration was 113+/-46 s. Behavioral seizure severity increased over time in the majority of animals. Secondarily-generalized seizures comprised an average of 66+/-37% of all seizures. Mossy fiber sprouting was increased in the ipsilateral hippocampus of animals with posttraumatic epilepsy compared with those subjected to traumatic brain injury without epilepsy. Stereologic cell counts indicated a loss of dentate hilar neurons ipsilaterally following traumatic brain injury. Our data suggest that posttraumatic epilepsy occurs with a frequency of 40% to 50% after severe non-penetrating fluid-percussion brain injury in rats, and that the lateral fluid percussion model can serve as a clinically-relevant tool for pathophysiologic and preclinical studies.

  15. Gas dynamics of heat-release-induced waves in supercritical fluids: revisiting the Piston Effect

    Science.gov (United States)

    Migliorino, Mario Tindaro; Scalo, Carlo

    2016-11-01

    We investigate a gasdynamic approach to the modeling of heat-release-induced compression waves in supercritical fluids. We rely on highly resolved one-dimensional fully compressible Navier-Stokes simulations of CO2 at pseudo-boiling conditions in a closed duct inspired by the experiments of Miura et al.. Near-critical fluids exhibit anomalous variations of thermodynamic variables taken into account by adopting the Peng-Robinson equation of state and Chung's Method. An idealized heat source is applied, away from the boundaries, resulting in the generation of compression waves followed by contact discontinuities bounding a region of hot expanding fluid. For higher heat-release rates such compressions are coalescent with distinct shock-like features (i.e. non-isentropicity and propagation Mach numbers measurably greater than unity) and a non-uniform post-shock state, not present in ideal gas simulations, caused by the highly nonlinear equation of state. Thermoacoustic effects are limited to: (1) a one-way/one-time thermal-to-acoustic energy conversion, and (2) cumulative non-isentropic bulk heating due to the resonating compression waves, resulting in what is commonly referred to as the Piston Effect.

  16. Fluid shear stress induces epithelial-mesenchymal transition (EMT) in Hep-2 cells

    Science.gov (United States)

    Shen, Yang; Zhang, Yingying; Yin, Hongmei; Zeng, Ye; Liu, Jingxia; Yan, Zhiping; Liu, Xiaoheng

    2016-01-01

    Laryngeal squamous cell carcinoma (LSCC) is one of the most commonly diagnosed malignancies with high occurrence of tumor metastasis, which usually exposes to fluid shear stress (FSS) in lymphatic channel and blood vessel. Epithelial-mesenchymal transition (EMT) is an important mechanism that induces metastasis and invasion of tumors. We hypothesized that FSS induced a progression of EMT in laryngeal squamous carcinoma. Accordingly, the Hep-2 cells were exposed to 1.4 dyn/cm2 FSS for different durations. Our results showed that most of cells changed their morphology from polygon to elongated spindle with well-organized F-actin and abundant lamellipodia/filopodia in protrusions. After removing the FSS, cells gradually recovered their flat polygon morphology. FSS induced Hep-2 cells to enhance their migration capacity in a time-dependent manner. In addition, FSS down-regulated E-cadherin, and simultaneously up-regulated N-cadherin, translocated β-catenin into the nucleus. These results confirmed that FSS induced the EMT in Hep-2 cells, and revealed a reversible mesenchymal-epithelial transition (MET) process when FSS was removed. We further examined the time-expressions of signaling cascades, and demonstrated that FSS induces the EMT and enhances cell migration depending on integrin-ILK/PI3K-AKT-Snail signaling events. The current study suggests that FSS, an important biophysical factor in tumor microenvironment, is a potential determinant of cell behavior and function regulation. PMID:27096955

  17. Fluid loading and norepinephrine infusion mask the left ventricular preload decrease induced by pleural effusion.

    Science.gov (United States)

    Wemmelund, Kristian Borup; Ringgård, Viktor Kromann; Vistisen, Simon Tilma; Hyldebrandt, Janus Adler; Sloth, Erik; Juhl-Olsen, Peter

    2017-09-11

    Pleural effusion (PLE) may lead to low blood pressure and reduced cardiac output. Low blood pressure and reduced cardiac output are often treated with fluid loading and vasopressors. This study aimed to determine the impact of fluid loading and norepinephrine infusion on physiologic determinants of cardiac function obtained by ultrasonography during PLE. In this randomised, blinded, controlled laboratory study, 30 piglets (21.9 ± 1.3 kg) had bilateral PLE (75 mL/kg) induced. Subsequently, the piglets were randomised to intervention as follows: fluid loading (80 mL/kg/h for 1.5 h, n = 12), norepinephrine infusion (0.01, 0.03, 0.05, 0.1, 0.2 and 0.3 μg/kg/min (15 min each, n = 12)) or control (n = 6). Main outcome was left ventricular preload measured as left ventricular end-diastolic area. Secondary endpoints included contractility and afterload as well as global measures of circulation. All endpoints were assessed with echocardiography and invasive pressure-flow measurements. PLE decreased left ventricular end-diastolic area, mean arterial pressure and cardiac output (p values  0.05) to baseline. Left ventricular contractility increased with norepinephrine infusion (p = 0.002), but was not affected by fluid loading (p = 0.903). Afterload increased in both active groups (p values > 0.001). Overall, inferior vena cava distensibility remained unchanged during intervention (p values ≥ 0.085). Evacuation of PLE caused numerical increases in left ventricular end-diastolic area, but only significantly so in controls (p = 0.006). PLE significantly reduced left ventricular preload. Both fluid and norepinephrine treatment reverted this effect and normalised global haemodynamic parameters. Inferior vena cava distensibility remained unchanged. The haemodynamic significance of PLE may be underestimated during fluid or norepinephrine administration, potentially masking the presence of PLE.

  18. Modeling of fluid-induced vibrations and identification of hydrodynamic forces on flow control valves

    Institute of Scientific and Technical Information of China (English)

    Samad Mehrzad; Ilgar Javanshir; Ahmad Rahbar Ranji; Seyyed Hadi Taheri

    2015-01-01

    Dynamics and vibration of control valves under flow-induced vibration are analyzed. Hydrodynamic load characteristics and structural response under flow-induced vibration are mainly influenced by inertia, damping, elastic, geometric characteristics and hydraulic parameters. The purpose of this work is to investigate the dynamic behavior of control valves in the response to self-excited fluid flow. An analytical and numerical method is developed to simulate the dynamic and vibrational behavior of sliding dam valves, in response to flow excitation. In order to demonstrate the effectiveness of proposed model, the simulation results are validated with experimental ones. Finally, to achieve the optimal valve geometry, numerical results for various shapes of valves are compared. Rounded valve with the least amount of flow turbulence obtains lower fluctuations and vibration amplitude compared with the flat and steep valves. Simulation results demonstrate that with the optimal design requirements of valves, vibration amplitude can be reduced by an average to 30%.

  19. Patterns of gravity induced aggregate migration during casting of fluid concretes

    Energy Technology Data Exchange (ETDEWEB)

    Spangenberg, J. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Roussel, N., E-mail: Nicolas.roussel@lcpc.fr [Universite Paris Est, Laboratoire Central des Ponts et Chaussees (LCPC) (France); Hattel, J.H. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Sarmiento, E.V.; Zirgulis, G. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Geiker, M.R. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Department of Civil Engineering, Technical University of Denmark (DTU) (Denmark)

    2012-12-15

    In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.

  20. Skeletal nutrient vascular adaptation induced by external oscillatory intramedullary fluid pressure intervention

    Directory of Open Access Journals (Sweden)

    Qin Yi-Xian

    2010-03-01

    Full Text Available Abstract Background Interstitial fluid flow induced by loading has demonstrated to be an important mediator for regulating bone mass and morphology. It is shown that the fluid movement generated by the intramedullary pressure (ImP provides a source for pressure gradient in bone. Such dynamic ImP may alter the blood flow within nutrient vessel adjacent to bone and directly connected to the marrow cavity, further initiating nutrient vessel adaptation. It is hypothesized that oscillatory ImP can mediate the blood flow in the skeletal nutrient vessels and trigger vasculature remodeling. The objective of this study was then to evaluate the vasculature remodeling induced by dynamic ImP stimulation as a function of ImP frequency. Methods Using an avian model, dynamics physiological fluid ImP (70 mmHg, peak-peak was applied in the marrow cavity of the left ulna at either 3 Hz or 30 Hz, 10 minutes/day, 5 days/week for 3 or 4 weeks. The histomorphometric measurements of the principal nutrient arteries were done to quantify the arterial wall area, lumen area, wall thickness, and smooth muscle cell layer numbers for comparison. Results The preliminary results indicated that the acute cyclic ImP stimuli can significantly enlarge the nutrient arterial wall area up to 50%, wall thickness up to 20%, and smooth muscle cell layer numbers up to 37%. In addition, 3-week of acute stimulation was sufficient to alter the arterial structural properties, i.e., increase of arterial wall area, whereas 4-week of loading showed only minimal changes regardless of the loading frequency. Conclusions These data indicate a potential mechanism in the interrelationship between vasculature adaptation and applied ImP alteration. Acute ImP could possibly initiate the remodeling in the bone nutrient vasculature, which may ultimately alter blood supply to bone.

  1. Perturbation of geothermal reservoirs to fluids stimulation: numerical modelling and implication on induced seismicity.

    Science.gov (United States)

    Carlino, Stefano; De Natale, Giuseppe; Troise, Claudia; Giulia Di Giuseppe, Maria; Troiano, Antonio; Tramelli, Anna; Somma, Renato

    2016-04-01

    Fluid withdrawal and injection into the crust produces changes in the local stress field and pore pressure, involving different rock volumes depending on the injection flow rate and duration as well as on the medium permeability. This process is in different cases correlated to induced seismicity. In the case of geothermal power plants (e.g. fluids withdrawal and in several case withdrawal/reinjection) this correlation is vague and sometimes not well constrained by experimental data. We report here a set of simulations of withdrawal, injection and withdrawal-reinjection-cycles from/in the same geothermal reservoirs, by using the numerical code TOUGH2®. The simulations are applied to conceptual models of different geothermal reservoirs already published in previous works, whose main difference is in the permeability features and the depth of wells (Soultz, France; Campi Flegrei caldera and Ischia island, Italy). The numerical simulations are aimed to compare the time growth of perturbed volumes obtained with withdrawal reinjection cycle to those obtained during simple withdrawal or injection, using the same flow rates. Our results clearly point out that reinjection is much less critical than simple injection or withdrawal, because the perturbed volumes are remarkably small and, moreover, remain constant over the simulated time, of whatever duration. This fact reduces significantly the potential of the seismicity induced by pressure variation into the reservoirs.

  2. Flow induced by ependymal cilia dominates near-wall cerebrospinal fluid dynamics in the lateral ventricles.

    Science.gov (United States)

    Siyahhan, Bercan; Knobloch, Verena; de Zélicourt, Diane; Asgari, Mahdi; Schmid Daners, Marianne; Poulikakos, Dimos; Kurtcuoglu, Vartan

    2014-05-06

    While there is growing experimental evidence that cerebrospinal fluid (CSF) flow induced by the beating of ependymal cilia is an important factor for neuronal guidance, the respective contribution of vascular pulsation-driven macroscale oscillatory CSF flow remains unclear. This work uses computational fluid dynamics to elucidate the interplay between macroscale and cilia-induced CSF flows and their relative impact on near-wall dynamics. Physiological macroscale CSF dynamics are simulated in the ventricular space using subject-specific anatomy, wall motion and choroid plexus pulsations derived from magnetic resonance imaging. Near-wall flow is quantified in two subdomains selected from the right lateral ventricle, for which dynamic boundary conditions are extracted from the macroscale simulations. When cilia are neglected, CSF pulsation leads to periodic flow reversals along the ventricular surface, resulting in close to zero time-averaged force on the ventricle wall. The cilia promote more aligned wall shear stresses that are on average two orders of magnitude larger compared with those produced by macroscopic pulsatile flow. These findings indicate that CSF flow-mediated neuronal guidance is likely to be dominated by the action of the ependymal cilia in the lateral ventricles, whereas CSF dynamics in the centre regions of the ventricles is driven predominantly by wall motion and choroid plexus pulsation.

  3. Experimental elaboration of faulting induced by fluid-releasing mineral reactions in subduction zones

    Science.gov (United States)

    Green, H.; Zhang, J.; Jung, H.; Dobrzinetskaya, L.

    2003-04-01

    Dehydration embrittlement has been cited repeatedly as a potential mechanism for triggering earthquakes at depths where unassisted brittle failure is impossible due to the normal-stress-dependence of friction. We are investigating two different aspects of this problem in the laboratory: (i) dehydration of antigorite under stress where the ΔV of reaction varies from strongly positive to distinctly negative; (ii) deformation of eclogite in which the nominally anhydrous minerals contain small amounts of dissolved H_2O that can lead to faulting induced by very small amounts of melting stimulated by exsolution of H_2O. (i) Antigorite has the largest stability field of the serpentines and is often cited as potentially being the source of most or all mantle earthquakes to a depth of over 200 km. However, like other low-pressure hydrous phases, the net volume change accompanying antigorite dehydration varies from strongly positive at low P to negative at P > ˜2-2.5 GPa. Fracture mechanics theory predicts that dehydration should not induce shear failure if ΔV<0. To test the effect of ΔV on faulting, we have deformed an extensively-serpentinized peridotite at P = 1-6 GPa. We conducted constant strain rate experiments in a Griggs-type apparatus at P = 1.0 - 3.4 GPa and rapid-pumping experiments in a Walker-type multianvil apparatus, culminating in pressures as high as 6 GPa. Independent of the sign of ΔV, specimens subjected to stress during dehydration yielded extremely thin zones of reaction products with shear offset across them. Some were clearly faults whereas others could be precursors to faulting. Fluid released at grain boundaries between antigorite and relict olivine locally produced Mode I cracks &fluid inclusions. (ii) Deformation of "wet" eclogite at 3 GPa and temperatures between the wet and dry solidi induced exsolution of H_2O and formation of very small amounts (<1%) of melt, leading to faulting. At lower temperature the rock was extremely strong but

  4. Can serpentinization induce fracturing? Fluid pathway development and the volume increase enigma

    Science.gov (United States)

    Plümper, Oliver; Jamtveit, Bjørn; Røyne, Anja

    2013-04-01

    Serpentinization of ultramafic rocks has first-order effects on global element cycles, the rheology of the oceanic lithosphere, plays a key role in plate tectonics by lubricating subduction zones and has been linked to the origin of life due to the creation of abiogenic hydrocarbons. In addition, the capability of ultramafic rocks to safely store enormous amounts of carbon dioxide through mineral reactions may provide a unique solution to fight global warming. However, all the aforementioned processes are reliant on the creation and maintenance of fluid pathways to alter an originally impermeable rock. Although the forces that move tectonic plates can produce these fluid pathways by mechanical fracturing, there is ample evidence that serpentinization reactions can 'eat' their way through a rock. This process is facilitated by solid volume changes during mineral reactions that cause expansion, fracturing the rock to generate fluid pathways. Natural observations of serpentinization/carbonation in ultramafic rocks indicate that the associated positive solid volume change alone exerts enough stress on the surrounding rock to build up a fracture network and that the influence of external tectonic forces is not necessary. Through various feedbacks these systems can either become self-sustaining, when an interconnected fracture network is formed, or self-limiting due to fluid pathway obstruction. However, extensively serpentinized outcrops suggest that although crystal growth in newly opened spaces would reduce permeability, serpentinization is not always self-limiting as porosity generation can occur concomitantly, maintaining or even increasing permeability. This is consistent with theory and demonstrates that fluids transported through fracture networks can alter vast amounts of originally impermeable rock. Nevertheless, whether serpentinization can actually generate these fracture networks is still a matter of debate and only a few scientific investigations have

  5. Numerical simulation of an elementary Vortex-Induced-Vibration problem by using fully-coupled fluid solid system computation

    Directory of Open Access Journals (Sweden)

    M Pomarède

    2016-09-01

    Full Text Available Numerical simulation of Vortex-Induced-Vibrations (VIV of a rigid circular elastically-mounted cylinder submitted to a fluid cross-flow has been extensively studied over the past decades, both experimentally and numerically, because of its theoretical and practical interest for understanding Flow-Induced-Vibrations (FIV problems. In this context, the present article aims to expose a numerical study based on fully-coupled fluid-solid computations compared to previously published work [34], [36]. The computational procedure relies on a partitioned method ensuring the coupling between fluid and structure solvers. The fluid solver involves a moving mesh formulation for simulation of the fluid structure interface motion. Energy exchanges between fluid and solid models are ensured through convenient numerical schemes. The present study is devoted to a low Reynolds number configuration. Cylinder motion magnitude, hydrodynamic forces, oscillation frequency and fluid vortex shedding modes are investigated and the “lock-in” phenomenon is reproduced numerically. These numerical results are proposed for code validation purposes before investigating larger industrial applications such as configurations involving tube arrays under cross-flows [4].

  6. Stimulation of MAP kinase pathways after maternal IL-1β exposure induces fetal lung fluid absorption in guinea pigs

    Directory of Open Access Journals (Sweden)

    Carter Ethan P

    2007-03-01

    Full Text Available Abstract Background We tested the hypothesis that maternal interleukin-1β (IL-1β pretreatment and induction of fetal cortisol synthesis activates MAP kinases and thereby affects lung fluid absorption in preterm guinea pigs. Methods IL-1β was administered subcutaneously daily to timed-pregnant guinea pigs for three days. Fetuses were obtained by abdominal hysterotomy and instilled with isosmolar 5% albumin into the lungs and lung fluid movement was measured over 1 h by mass balance. MAP kinase expression was measured by western blot. Results Lung fluid absorption was induced at 61 days (D gestation and stimulated at 68D gestation by IL-1β. Maternal IL-1β pretreatment upregulated ERK and upstream MEK expression at both 61 and 68D gestation, albeit being much more pronounced at 61D gestation. U0126 instillation completely blocked IL-1β-induced lung fluid absorption as well as IL-1β-induced/stimulated ERK expression. Cortisol synthesis inhibition by metyrapone attenuated ERK expression and lung fluid absorption in IL-1β-pretreated fetal lungs. JNK expression after maternal IL-1β pretreatment remained unaffected at either gestation age. Conclusion These data implicate the ERK MAP kinase pathway as being important for IL-1β induction/stimulation of lung fluid absorption in fetal guinea pigs.

  7. Stimulation of MAP kinase pathways after maternal IL-1beta exposure induces fetal lung fluid absorption in guinea pigs.

    Science.gov (United States)

    Bhattacharjee, Reshma; Li, Tianbo; Koshy, Shyny; Beard, LaMonta L; Sharma, Kapil; Carter, Ethan P; Garat, Chrystelle; Folkesson, Hans G

    2007-03-26

    We tested the hypothesis that maternal interleukin-1beta (IL-1beta) pretreatment and induction of fetal cortisol synthesis activates MAP kinases and thereby affects lung fluid absorption in preterm guinea pigs. IL-1beta was administered subcutaneously daily to timed-pregnant guinea pigs for three days. Fetuses were obtained by abdominal hysterotomy and instilled with isosmolar 5% albumin into the lungs and lung fluid movement was measured over 1 h by mass balance. MAP kinase expression was measured by western blot. Lung fluid absorption was induced at 61 days (D) gestation and stimulated at 68D gestation by IL-1beta. Maternal IL-1beta pretreatment upregulated ERK and upstream MEK expression at both 61 and 68D gestation, albeit being much more pronounced at 61D gestation. U0126 instillation completely blocked IL-1beta-induced lung fluid absorption as well as IL-1beta-induced/stimulated ERK expression. Cortisol synthesis inhibition by metyrapone attenuated ERK expression and lung fluid absorption in IL-1beta-pretreated fetal lungs. JNK expression after maternal IL-1beta pretreatment remained unaffected at either gestation age. These data implicate the ERK MAP kinase pathway as being important for IL-1beta induction/stimulation of lung fluid absorption in fetal guinea pigs.

  8. Numerical and analytical treatment on peristaltic flow of Williamson fluid in the occurrence of induced magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Safia, E-mail: safia_akram@yahoomail.com [Department of Basic Sciences, Military College of Signals, National University of Sciences and Technology (Pakistan); Nadeem, S. [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan); Hanif, M. [Department of Basic Sciences, Military College of Signals, National University of Sciences and Technology (Pakistan)

    2013-11-15

    In this paper the effects of induced magnetic field on the peristaltic transport of a Williamson fluid model in an asymmetric channel has been investigated. The problem is simplified by using long wave length and low Reynolds number approximations. The perturbation and numerical solutions have been presented. The expressions for pressure rise, pressure gradient, stream function, magnetic force function, current density distribution have been computed. The results of pertinent parameters have been discussed graphically. The trapping phenomena for different wave forms have been also discussed. - highlights: • The main motivation of this work is that we want to see the behavior of peristaltic flow of Williamson fluid in the occurrence of induced magnetic field. In literature no attempt is taken to discuss the lateral Numerical and analytical treatment on peristaltic flow of Williamson fluid in the occurrence of induced magnetic field. • We do not want to fill the gap in literature after studying this.

  9. Syrinx fluid transport: modeling pressure-wave-induced flux across the spinal pial membrane.

    Science.gov (United States)

    Elliott, N S J

    2012-03-01

    Syrinxes are fluid-filled cavities of the spinal cord that characterize syringomyelia, a disease involving neurological damage. Their formation and expansion is poorly understood, which has hindered successful treatment. Syrinx cavities are hydraulically connected with the spinal subarachnoid space (SSS) enveloping the spinal cord via the cord interstitium and the network of perivascular spaces (PVSs), which surround blood vessels penetrating the pial membrane that is adherent to the cord surface. Since the spinal canal supports pressure wave propagation, it has been hypothesized that wave-induced fluid exchange across the pial membrane may play a role in syrinx filling. To investigate this conjecture a pair of one-dimensional (1-d) analytical models were developed from classical elastic tube theory coupled with Darcy's law for either perivascular or interstitial flow. The results show that transpial flux serves as a mechanism for damping pressure waves by alleviating hoop stress in the pial membrane. The timescale ratio over which viscous and inertial forces compete was explicitly determined, which predicts that dilated PVS, SSS flow obstructions, and a stiffer and thicker pial membrane-all associated with syringomyelia-will increase transpial flux and retard wave travel. It was also revealed that the propagation of a pressure wave is aided by a less-permeable pial membrane and, in contrast, by a more-permeable spinal cord. This is the first modeling of the spinal canal to include both pressure-wave propagation along the spinal axis and a pathway for fluid to enter and leave the cord, which provides an analytical foundation from which to approach the full poroelastic problem.

  10. Effects of temperature gradient induced nanoparticle motion on conduction and convection of fluid

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Leping, E-mail: lpzhou@ncepu.edu.cn [North China Electric Power University, Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education, School of Energy, Power and Mechanical Engineering (China); Peterson, George P.; Yoda, Minani [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering (United States); Wang Buxuan [Tsinghua University, Department of Thermal Engineering (China)

    2012-03-15

    The role of temperature gradient induced nanoparticle motion on conduction and convection was investigated. Possible mechanisms for variations resulting from variations in the thermophysical properties are theoretically and experimentally discussed. The effect of the nanoparticle motion on conduction is demonstrated through thermal conductivity measurement of deionized water with suspended CuO nanoparticles (50 nm in diameter) and correlated with the contributions of Brownian diffusion, thermophoresis, etc. The tendencies observed is that the magnitude of and the variation in the thermal conductivity increases with increasing volume fraction for a given temperature, which is due primarily to the Brownian diffusion of the nanoparticles. Using dimensional analysis, the thermal conductivity is correlated and both the interfacial thermal resistance and near-field radiation are found to be essentially negligible. A modification term that incorporates the contributions of Brownian motion and thermophoresis is proposed. The effect of nanoscale convection is illustrated through an experimental investigation that utilized fluorescent polystyrene nanoparticle tracers (200 nm in diameter) and multilayer nanoparticle image velocimetry. The results indicate that both the magnitude and the deviation of the fluid motion increased with increasing heat flux in the near-wall region. Meanwhile, the fluid motion tended to decrease with the off-wall distance for a given heating power. A corresponding numerical study of convection of pure deionized water shows that the velocity along the off-wall direction is several orders of magnitude lower than that of deionized water, which indicates that Brownian motion in the near-wall region is crucial for fluid with suspended nanoparticles in convection.

  11. Inducing rostrum interfacial waves by fluid-solid coupling in a Chinese river dolphin (Lipotes vexillifer )

    Science.gov (United States)

    Song, Zhongchang; Zhang, Yu; Wei, Chong; Wang, Xianyan

    2016-01-01

    Through numerically solving the appropriate wave equations, propagation of biosonar signals in a Chinese river dolphin (baiji) was studied. The interfacial waves along the rostrum-tissue interfaces, including both compressional (longitudinal) and shear (transverse) waves in the solid rostrum through fluid-solid coupling were examined. The baiji's rostrum was found to effect acoustic beam formation not only as an interfacial wave generator but also as a sound reflector. The wave propagation patterns in the solid rostrum were found to significantly change the wave movement through the bone. Vibrations in the rostrum, expressed in solid displacement, initially increased but eventually decreased from posterior to anterior sides, indicating a complex physical process. Furthermore, the comparisons among seven cases, including the combination of (1) the rostrum, melon, and air sacs; (2) rostrum-air sacs; (3) rostrum-melon; (4) only rostrum; (5) air sacs-melon; (6) only air sacs; and (7) only melon revealed that the cases including the rostrum were better able to approach the complete system by inducing rostrum-tissue interfacial waves and reducing the differences in main beam angle and -3 dB beam width. The interfacial waves in the rostrum were considered complementary with reflection to determine the obbligato role of the rostrum in the baiji's biosonar emission. The far-field beams formed from complete fluid-solid models and non-fluid-solid models were compared to reveal the effects brought by the consideration of shear waves of the solid structures of the baiji. The results may provide useful information for further understanding the role of the rostrum in this odontocete species.

  12. Amniotic fluid stem cells from EGFP transgenic mice attenuate hyperoxia-induced acute lung injury.

    Directory of Open Access Journals (Sweden)

    Shih-Tao Wen

    Full Text Available High concentrations of oxygen aggravate the severity of lung injury in patients requiring mechanical ventilation. Although mesenchymal stem cells have been shown to effectively attenuate various injured tissues, there is limited information regarding a role for amniotic fluid stem cells (AFSCs in treating acute lung injury. We hypothesized that intravenous delivery of AFSCs would attenuate lung injury in an experimental model of hyperoxia-induced lung injury. AFSCs were isolated from EGFP transgenic mice. The in vitro differentiation, surface markers, and migration of the AFSCs were assessed by specific staining, flow cytometry, and a co-culture system, respectively. The in vivo therapeutic potential of AFSCs was evaluated in a model of acute hyperoxia-induced lung injury in mice. The administration of AFSCs significantly reduced the hyperoxia-induced pulmonary inflammation, as reflected by significant reductions in lung wet/dry ratio, neutrophil counts, and the level of apoptosis, as well as reducing the levels of inflammatory cytokine (IL-1β, IL-6, and TNF-α and early-stage fibrosis in lung tissues. Moreover, EGFP-expressing AFSCs were detected and engrafted into a peripheral lung epithelial cell lineage by fluorescence microscopy and DAPI stain. Intravenous administration of AFSCs may offer a new therapeutic strategy for acute lung injury (ALI, for which efficient treatments are currently unavailable.

  13. Prolonged exercise following diuretic-induced hypohydration effects on fluid and electrolyte hormones.

    Science.gov (United States)

    Roy, B D; Green, H J; Burnett, M

    2001-09-01

    To investigate the hypothesis that a reduction in plasma volume (PV) induced by diuretic administration would result in an increase in the fluid and electrolyte hormonal response to exercise, ten untrained males (VO(2) peak = 3.96 +/- 0.14 l/min) performed 60 min of cycle ergometry at 61 % VO(2) peak twice. The test was carried out once under control conditions (CON) (placebo) and once after 4 days of diuretic administration (DIU) (Novotriamazide; 100 mg triamterene and 50 mg hydrochlorothiazide). Calculated resting PV decreased by 14.6 +/- 3.3 % (p DIU. No difference in plasma osmolality was observed between conditions. For the hormones measured, differences (p DIU led to higher levels of PRA, ANG I, and ALD (p DIU compared to CON (p DIU could be explained both by higher resting levels and a greater increase during exercise itself. For ANG I and NE, the effect of DIU only manifested itself during exercise. In contrast, the lower alpha-ANP observed during exercise with DIU was due to the lower resting levels. These results support the hypotheses that hypohydration leads to alterations in the secretion of all of the fluid and electrolyte hormones with the exception of AVP. The specific mechanisms of these alterations remain unclear, but appear to be related directly to the decrease in PV.

  14. Turbulence-induced melting of a nonequilibrium vortex crystal in a forced thin fluid film

    CERN Document Server

    Perlekar, Prasad

    2009-01-01

    To develop an understanding of recent experiments on the turbulence-induced melting of a periodic array of vortices in a thin fluid film, we perform a direct numerical simulation of the two-dimensional Navier-Stokes equations forced such that, at low Reynolds numbers, the steady state of the film is a square lattice of vortices. We find that, as we increase the Reynolds number, this lattice undergoes a series of nonequilibrium phase transitions, first to a crystal with a different reciprocal lattice and then to a sequence of crystals that oscillate in time. Initially the temporal oscillations are periodic; this periodic behaviour becomes more and more complicated, with increasing Reynolds number, until the film enters a spatially disordered nonequilibrium statistical steady that is turbulent. We study this sequence of transitions by using fluid-dynamics measures, such as the Okubo-Weiss parameter that distinguishes between vortical and extensional regions in the flow, ideas from nonlinear dynamics, e.g., \\Poi...

  15. Floret-shaped solid domains on giant fluid lipid vesicles induced by pH

    Science.gov (United States)

    Sofou, Stavroula; Bandekar, Amey

    2012-02-01

    Lateral lipid phase separation and domain formation induced by changes in pH is significant in liposome-based drug delivery: environmentally responsive lipid heterogeneities can be tuned to alter collective membrane properties such as drug release and drug carrier reactivity impacting, therefore, the therapeutic outcomes. At the micron-meter scale, fluorescence microscopy on Giant Unilamellar fluid Vesicles (GUVs) shows that lowering pH (from 7.0 to 5.0) promotes the condensation of titratable PS or PA lipids into beautiful floret-shaped solid domains in which lipids are tightly packed via H-bonding and VdWs interactions. Solid domains phenomenologically comprise a circular ``core'' cap beyond which interfacial instabilities emerge resembling leaf-like stripes of almost vanishing Gaussian curvature independent of GUVs' preparation path and in agreement with a general condensation mechanism. Increasing incompressibility of domains is strongly correlated with larger number of thinner stripes per domain, and increasing relative rigidity of domains with smaller core cap areas. Line tension drives domain ripening, however the final domain shape is a result of enhanced incompressibility and rigidity maximized by domain coupling across the bilayer. Introduction of a transmembrane osmotic gradient (hyperosmotic on the outer lipid leaflet) allows the domain condensation process to reach its maximum extent which, however, is limited by the minimal expansivity of the continuous fluid membrane.

  16. Stochastic modeling of fluid-particle flows in homogeneous cluster-induced turbulence

    Science.gov (United States)

    Innocenti, Alessio; Chibbaro, Sergio; Fox, Rodney; Salvetti, Maria Vittoria

    2016-11-01

    Inertial particles in turbulent flows are characterized by preferential concentration and segregation and, at sufficient mass loading, dense clusters may spontaneously generate due to momentum coupling between the phases. These clusters in turn can generate and sustain turbulence in the fluid phase, which we refer to as cluster-induced turbulence (CIT). In the present work, we tackle the problem of homogeneous gravity driven CIT in the framework of a stochastic model, based on a Lagrangian formalism which includes naturally the Eulerian one. A rigorous formalism has been put forward focusing in particular on the terms responsible of the two-way coupling in the carrier phase, which is the key mechanism in this type of flow. Moreover, the decomposition of the particle-phase velocity into the spatially correlated and uncorrelated components has been used allowing to identify the contributions to the correlated fluctuating energy and to the granular temperature. Tests have been performed taking into account also the effects of collisions between particles. Results are compared against DNS, and they show a good accuracy in predicting first and second order moments of particle velocity and fluid velocity seen by particles.

  17. FLOW-INDUCED INTERNAL RESONANCES AND MODE EXCHANGE IN HORIZONTAL CANTILEVERED PIPE CONVEYING FLUID (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    XU Jian; YANG Qian-biao

    2006-01-01

    Based on the nonlinear mathematical model of motion of a horizontally cantilevered rigid pipe conveying fluid, the 3:1 internal resonance induced by the minimum critical velocity is studied in details. With the detuning parameters of internal and primary resonances and the amplitude of the external disturbing excitation varying, the flow in the neighborhood of the critical flow velocity yields that some nonlinearly dynamical behaviors occur in the system such as mode exchange, saddle-node, Hopf and co-dimension 2 bifurcations. Correspondingly, the periodic motion losses its stability by jumping or flutter, and more complicated motions occur in the pipe under consideration.The good agreement between the analytical analysis and the numerical simulation for several parameters ensures the validity and accuracy of the present analysis.

  18. Two-dimensional nonstationary flow of a conducting fluid, induced by a rotating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kapusta, A.B.

    1977-07-01

    An examination is made of a full induction problem on the planar movement of a conducting fluid in a rotating magnetic field. The solution to this problem is sought by the method of degradation into Fourier series by harmonics of the rotating field. The initial system of partial differential equations is reduced to the system 2+1 of normal differential equations that bind the amplitudes of function harmonics and electrical vector potential. A solution to the problem for small anti ..omega.. was found with an accuracy up to the second approximation. The unsteadiness of flow was found to be manifested in a form of induced cross-sectional waves, traveling along the stream tubes of this flow at a speed that is equal to the phase velocity of the magnetic field. The appearance of wave effects is explained by considerations of symmetry. 5 references, 1 figure.

  19. Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume

    Science.gov (United States)

    Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.

    1995-01-01

    The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.

  20. Rupture directivity of fluid-induced microseismic events: Observations from an enhanced geothermal system

    Science.gov (United States)

    Folesky, Jonas; Kummerow, Jörn; Shapiro, Serge A.; Häring, Markus; Asanuma, Hiroshi

    2016-11-01

    The rupture process of fluid-induced microseismic events is still poorly understood, mainly due to usually small magnitudes and sparse monitoring geometries. The high-quality recordings of the earthquake sequence 2006-2007 at the enhanced geothermal system at Basel, Switzerland, constitute a rare exception, allowing a systematic directivity study of 195 events using the empirical Green's function method. We observe clear directivity signatures for about half the events which demonstrates that rupture directivity persists down to small magnitudes (ML˜1). The predominant rupture behavior is unilateral. We further find evidence that directivity is magnitude dependent and varies systematically with distance from the injection source. Whereas pore pressure seems to play the dominant role close to the injection source and no preferred rupture direction is observable, directivity aligns parallel to the event distribution with increasing distance (≳100 m) and is preferably oriented away from the injection point. The largest analyzed events (ML˜2) show a distinct behavior: They rupture toward the injection source, suggesting that they nucleate in the vicinity of the pressure front and propagate backward into the perturbed volume. This finding is of particular relevance for seismic hazard assessment of georeservoirs, since it implies that maximum event size is related to dimension of the fluid-perturbed volume. Our study also resolves rupture complexities for a small group of events. This shows that small fault heterogeneities exist down to a scale of a few tens of meters. The observation of directivity and complexity in induced microseismic events suggest that future source studies account for these phenomena.

  1. Physics-based Probabilistic Seismic Hazard Analysis for Seismicity Induced by Fluid Injection

    Science.gov (United States)

    Foxall, W.; Hutchings, L. J.; Johnson, S.; Savy, J. B.

    2011-12-01

    Risk associated with induced seismicity (IS) is a significant factor in the design, permitting and operation of enhanced geothermal, geological CO2 sequestration and other fluid injection projects. Whereas conventional probabilistic seismic hazard and risk analysis (PSHA, PSRA) methods provide an overall framework, they require adaptation to address specific characteristics of induced earthquake occurrence and ground motion estimation, and the nature of the resulting risk. The first problem is to predict the earthquake frequency-magnitude distribution of induced events for PSHA required at the design and permitting stage before the start of injection, when an appropriate earthquake catalog clearly does not exist. Furthermore, observations and theory show that the occurrence of earthquakes induced by an evolving pore-pressure field is time-dependent, and hence does not conform to the assumption of Poissonian behavior in conventional PSHA. We present an approach to this problem based on generation of an induced seismicity catalog using numerical simulation of pressure-induced shear failure in a model of the geologic structure and stress regime in and surrounding the reservoir. The model is based on available measurements of site-specific in-situ properties as well as generic earthquake source parameters. We also discuss semi-empirical analysis to sequentially update hazard and risk estimates for input to management and mitigation strategies using earthquake data recorded during and after injection. The second important difference from conventional PSRA is that in addition to potentially damaging ground motions a significant risk associated with induce seismicity in general is the perceived nuisance caused in nearby communities by small, local felt earthquakes, which in general occur relatively frequently. Including these small, usually shallow earthquakes in the hazard analysis requires extending the ground motion frequency band considered to include the high

  2. Fluid shear stress inhibits TNF-α-induced osteoblast apoptosis via ERK5 signaling pathway.

    Science.gov (United States)

    Bin, Geng; Cuifang, Wang; Bo, Zhang; Jing, Wang; Jin, Jiang; Xiaoyi, Tan; Cong, Chen; Yonggang, Chen; Liping, An; Jinglin, Ma; Yayi, Xia

    2015-10-09

    Fluid shear stress (FSS) is a potent mechanical stimulus and prevents cells from TNF-a-induced apoptosis. Recently, Extracellular-signal-regulated kinase 5 (ERK5) has been found to be involved in regulation of cell survival. However, little is known about the role of ERK5 signaling pathway in FSS-mediated anti-apoptotic effects in osteoblast. In this study, we show that FSS blocks TNF-a-induced apoptosis of MC3T3-E1 cells via ERK5 signaling pathway. We found that physiological FSS for 1 h significantly decreased TNF-α-induced MC3T3-E1 cells apoptosis. After inhibition of ERK5 activity by XMD8-92, a highly-selective inhibitor of ERK5 activity, the ability of FSS to inhibit TNF-α induced apoptosis was significantly decreased. Analysis of anti-apoptotic mechanisms indicated that exposure of MC3T3-E1 cells to FSS for 1 h increased phosphorylation of Bad and inhibited caspase-3 activity. After treatment with XMD8-92, phosphorylation of Bad by FSS was significantly blocked, but caspase-3 activity was increased. In summary, these findings indicated that FSS inhibits TNF-α-mediated signaling events in osteoblast by a mechanism dependent on activation of ERK5, and Bad is a crucial downstream target for ERK5. Those results implied that ERK5 signaling pathway play a crucial role in FSS-mediated anti-apoptotic effect in osteoblast. Thus, ERK5 signaling pathway may be a new drug treatment target of osteoporosis and related bone-wasting diseases.

  3. Cellular changes in bronchoalveolar lavage fluid in hyperoxia-induced lung injury

    Institute of Scientific and Technical Information of China (English)

    Xinbiao HE; Wei ZHAO

    2008-01-01

    It is well known that high concentration oxy-gen exposure is a model of acute lung injury (ALI). However, controversy exists over the mechanism. This study was designed to clarify the cellular characteristics in bronchoalveolar lavage fluid (BALF) and body weight loss of rats exposed to oxygen(>90%). Young male Wistar rats, aged 6 weeks, were divided into three groups: (1) room air group (exposed to room air, n=22); (2) hyperoxia < 48 h group (exposed to over 90% oxygen for less than 48 h, n=18); (3) hyperoxia 66-72 h group (exposed to over 90% oxygen for 66-72 h group, n=7). Compared to the room air group, the total cell counts in the hyperoxia 66-72 h group decreased, whereas the neu-trophils increased significantly. The body weights of the rats exposed to room air continued to increase. However, the body weights of oxygen-exposed rats increased slightly on the first day and weight loss was seen from the second day. All rats were noted to have bilateral pleural effusion in the hyperoxia 66-72 h group. The data suggests that (1) an increase in neutrophil count is an evident feature of hyperoxia-induced lung injury; (2) high concentration oxygen exposure can give rise to anorexia and malnutri-tion, which may play a role in hyperoxia-induced lung injury. Blocking neutrophil influx into lung tissue in the early phase and improving malnutrition are two effective methods to reduce hyperoxic lung injury.

  4. Rupture Complexities of Fluid Induced Microseismic Events at the Basel EGS Project

    Science.gov (United States)

    Folesky, Jonas; Kummerow, Jörn; Shapiro, Serge A.; Häring, Markus; Asanuma, Hiroshi

    2016-04-01

    Microseismic data sets of excellent quality, such as the seismicity recorded in the Basel-1 enhanced geothermal system, Switzerland, in 2006-2007, provide the opportunity to analyse induced seismic events in great detail. It is important to understand in how far seismological insights on e.g. source and rupture processes are scale dependent and how they can be transferred to fluid induced micro-seismicity. We applied the empirical Green's function (EGF) method in order to reconstruct the relative source time functions of 195 suitable microseismic events from the Basel-1 reservoir. We found 93 solutions with a clear and consistent directivity pattern. The remaining events display either no measurable directivity, are unfavourably oriented or exhibit non consistent or complex relative source time functions. In this work we focus on selected events of M ˜ 1 which show possible rupture complexities. It is demonstrated that the EGF method allows to resolve complex rupture behaviour even if it is not directly identifiable in the seismograms. We find clear evidence of rupture directivity and multi-phase rupturing in the analysed relative source time functions. The time delays between consecutive subevents lies in the order of 10ms. Amplitudes of the relative source time functions of the subevents do not always show the same azimuthal dependence, indicating dissimilarity in the rupture directivity of the subevents. Our observations support the assumption that heterogeneity on fault surfaces persists down to small scale (few tens of meters).

  5. Cerebrospinal fluid from rats given hypoxic preconditioning protects neurons from oxygen-glucose deprivation-induced injury.

    Science.gov (United States)

    Zhang, Yan-Bo; Guo, Zheng-Dong; Li, Mei-Yi; Li, Si-Jie; Niu, Jing-Zhong; Yang, Ming-Feng; Ji, Xun-Ming; Lv, Guo-Wei

    2015-09-01

    Hypoxic preconditioning activates endogenous mechanisms that protect against cerebral ischemic and hypoxic injury. To better understand these protective mechanisms, adult rats were housed in a hypoxic environment (8% O2/92% N2) for 3 hours, and then in a normal oxygen environment for 12 hours. Their cerebrospinal fluid was obtained to culture cortical neurons from newborn rats for 1 day, and then the neurons were exposed to oxygen-glucose deprivation for 1.5 hours. The cerebrospinal fluid from rats subjected to hypoxic preconditioning reduced oxygen-glucose deprivation-induced injury, increased survival rate, upregulated Bcl-2 expression and downregulated Bax expression in the cultured cortical neurons, compared with control. These results indicate that cerebrospinal fluid from rats given hypoxic preconditioning protects against oxygen-glucose deprivation-induced injury by affecting apoptosis-related protein expression in neurons from newborn rats.

  6. RELATIONSHIP BETWEEN OOCYTE MATURITY FOR FERTILIZATION AND PRE-OVULATORY FOLLICULAR FLUID HORMONE LEVELS IN INDUCED OVULATORYCY CLE

    Institute of Scientific and Technical Information of China (English)

    LIUYong

    1989-01-01

    This paper describes the relationship between haman oocyte matarity for fcrtilization andpre-ovulalory follicular fluid hormone levels in induced ova]story cycle by trealmcm withclomiphenz+HMG or clomiphene+HMC+HCG. 32 hours after urine LH--surge or 34

  7. Laboratory simulations of fluid/gas induced micro-earthquakes: application to volcano seismology

    OpenAIRE

    Philip Michael Benson; Sergio eVinciguerra; Mohamed eNasseri; R Paul Young

    2014-01-01

    Understanding different seismic signals recorded in active volcanic regions allows geoscientists to derive insight into the processes that generate them. A key type is known as Low Frequency or Long Period (LP) event, generally understood to be generated by different fluid types resonating in cracks and faults. The physical mechanisms of these signals have been linked to either resonance/turbulence within fluids, or as a result of fluids ‘sloshing’ due to a mixture of gas and fluid being pr...

  8. Blow-up Solutions to a Viscoelastic Fluid System and a Coupled Navier-Stokes/Phase-Field System in R2

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li-Yun; GUO Bo-Ling; HUANG Hai-Yang

    2011-01-01

    @@ The explicit solutions to both the Oldroyd-B model with an infinite Weissenberg number and the coupled Navier- Stokes/phase-field system are constructed by the method of separation of variables.It is found that the solutions blow up in finite time.%The explicit solutions to both the Oldroyd-B model with an infinite Weissenberg number and the coupled Navier- Stokes/phase-Beld system are constructed by the method of separation of variables. It is found that the solutions blow up in finite time.

  9. Abdominal obesity can induce both systemic and follicular fluid oxidative stress independent from polycystic ovary syndrome.

    Science.gov (United States)

    Nasiri, Nahid; Moini, Ashraf; Eftekhari-Yazdi, Poopak; Karimian, Leila; Salman-Yazdi, Reza; Zolfaghari, Zahra; Arabipoor, Arezoo

    2015-01-01

    The abdominal form of obesity is prevalent in women with polycystic ovary syndrome (PCOS). Visceral fat accumulation seems to play an important role in etiology of PCOS. In this cross-sectional study we evaluated the association of oxidative stress (OS) induced with PCOS and abdominal obesity in serum and follicular fluid (FF) of infertile women. A total of 80 women younger than 37 years old undergoing an IVF program were studied in the same period of time from September 2012 to October 2013. Blood serum and FF obtained from 40 women with PCOS (diagnosed by the Rotterdam 2004 criteria) and 40 women without PCOS undergoing IVF were evaluated for two OS markers: lipid peroxide (LPO) and total antioxidant capacity (TAC), after puncture. The patients were divided into 4 groups on the basis of presence of PCOS and waist-to-hip ratio (WHR) or abdominal obesity (OA). Healthy and PCOS women with abdominal obesity had significantly higher amounts of LPO in the serum and FF as compared with women without abdominal obesity. LPO concentration in FF was significantly lower than in serum and corroborates the hypothesis that the germinal cells have a potent antioxidant mechanism. We also found that LPO concentration in the PCOS group associated with AO had an increasing trend vs. those AO patients without PCOS but this difference was not significant, so the increase in LPO level was approximately independent of PCOS. Based on our results, the association and interaction between PCOS and AO can lead to TAC concentration reduction in patients. Abdominal obesity can induce local and systemic oxidative stress in PCOS and non-PCOS patients. We suggest that PCOS-induced disorders are likely to be exacerbated in the presence of abdominal obesity. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Purinergic signaling is required for fluid shear stress-induced NF-{kappa}B translocation in osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Genetos, Damian C., E-mail: dgenetos@ucdavis.edu [Department of Anatomy, Cell Biology, and Physiology, School of Veterinary Medicine, University of California, Davis, CA (United States); Karin, Norman J. [Cell Biology and Biochemistry, Pacific Northwest National Laboratory, Richland, WA (United States); Geist, Derik J. [Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN (United States); Donahue, Henry J. [Division of Musculoskeletal Sciences, Department of Orthopaedics and Rehabilitation, Pennsylvania State College of Medicine, Hershey, PA (United States); Duncan, Randall L. [Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN (United States)

    2011-04-01

    Fluid shear stress regulates gene expression in osteoblasts, in part by activation of the transcription factor NF-{kappa}B. We examined whether this process was under the control of purinoceptor activation. MC3T3-E1 osteoblasts under static conditions expressed the NF-{kappa}B inhibitory protein I{kappa}B{alpha} and exhibited cytosolic localization of NF-{kappa}B. Under fluid shear stress, I{kappa}B{alpha} levels decreased, and concomitant nuclear localization of NF-{kappa}B was observed. Cells exposed to fluid shear stress in ATP-depleted medium exhibited no significant reduction in I{kappa}B{alpha}, and NF-{kappa}B remained within the cytosol. Similar results were found using oxidized ATP or Brilliant Blue G, P2X{sub 7} receptor antagonists, indicating that the P2X{sub 7} receptor is responsible for fluid shear-stress-induced I{kappa}B{alpha} degradation and nuclear accumulation of NF-{kappa}B. Pharmacologic blockage of the P2Y6 receptor also prevented shear-induced I{kappa}B{alpha} degradation. These phenomena involved neither ERK1/2 signaling nor autocrine activation by P2X{sub 7}-generated lysophosphatidic acid. Our results suggest that fluid shear stress regulates NF-{kappa}B activity through the P2Y{sub 6} and P2X{sub 7} receptor.

  11. Influence of sterilization on the mineralization of titanium implants induced by incubation in various biological model fluids.

    Science.gov (United States)

    Serro, A P; Saramago, B

    2003-11-01

    The aim of this work was to investigate the effect of the sterilization processes on the mineralization of titanium implants induced by incubation in various biological model fluids. Titanium samples were submitted to the following sterilization processes used for implant materials: steam autoclaving, glow discharge Ar plasma treatment and gamma-irradiation. The modification of the treated surfaces was evaluated by contact angle determinations, X-ray photoelectron spectroscopy (XPS), laser profilometry and X-ray diffraction. The most significant modifications were detected on the wettability: while the samples treated with Ar plasma became highly hydrophilic (water contact angle approximately 0 degrees), gamma-irradiation and steam sterilization induced an increase in the hydrophobicity. After being sterilized, the samples were incubated for one week in three biological model fluids: Hanks' Balanced Salt Solution, Kokubo's simulated body fluid (SBF) and a fluid, designated by SBF0, with the same composition of SBF but without buffer TRIS. The level of mineralization of the incubated Ti samples, assessed by dynamic contact angle analysis, scanning electron microscopy, electron dispersive spectroscopy and XPS, indicated that the early stages of mineralization are essentially independent of the sterilization method. In contrast, the incubating fluid plays a determinant role, SBFO being the most efficient medium for biomineralization of titanium.

  12. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

    Science.gov (United States)

    Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

    2016-12-01

    Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

  13. Effects of fracture contact areas on seismic attenuation due to wave-induced fluid flow

    Science.gov (United States)

    Germán Rubino, J.; Müller, Tobias M.; Milani, Marco; Holliger, Klaus

    2014-05-01

    Wave-induced fluid flow (WIFF) between fractures and the embedding matrix is considered to be a predominant seismic attenuation mechanism in fractured rocks. That is, due to the strong compressibility contrast between fractures and embedding matrix, seismic waves induce strong fluid pressure gradients, followed by local fluid flow between such regions, which in turn produces significant energy dissipation. Natural fractures can be conceptualized as two surfaces in partial contact, containing very soft and highly permeable material in the inner region. It is known that the characteristics of the fracture contact areas control the mechanical properties of the rock sample, since as the contact area increases, the fracture becomes stiffer. Correspondingly, the detailed characteristics of the contact area of fractures are expected to play a major role in WIFF-related attenuation. To study this topic, we consider a simple model consisting of a horizontal fracture located at the center of a porous rock sample and represented by a number of rectangular cracks of constant height separated by contact areas. The cracks are modelled as highly compliant, porous, and permeable heterogeneities, which are hydraulically connected to the background material. We include a number of rectangular regions of background material separating the cracks, which represent the presence of contact areas of the fracture. In order to estimate the WIFF effects, we apply numerical oscillatory relaxation tests based on the quasi-static poro-elastic equations. The equivalent undrained, complex plane-wave modulus, which allows to estimate seismic attenuation and velocity dispersion for the vertical direction of propagation, is expressed in terms of the imposed displacement and the resulting average vertical stress at the top boundary. In order to explore the effects of the presence of fracture contact areas on WIFF effects, we perform an exhaustive sensitivity analysis considering different

  14. Alterations in bronchoalveolar lavage fluid during ischemia-induced acute hepatic failure in the pig.

    Science.gov (United States)

    Kostopanagiotou, Georgia; Routsi, Christina; Smyrniotis, Vassilios; Lekka, Marilena E; Kitsiouli, Eirini; Arkadopoulos, Nikolaos; Nakos, George

    2003-05-01

    The objective of this controlled experimental animal study was to evaluate whether acute hepatic failure (AHF) can cause acute lung injury (ALI) and to investigate possible pathophysiologic mechanisms. Seventeen domestic pigs were randomly assigned to AHF and sham groups. AHF was induced by surgical devascularization of liver in 10 animals. Seven animals were sham operated. Hemodynamics, lung mechanics, extravascular lung water (EVLW), and intracranial pressure, blood gas, liver function tests, and serum endotoxin levels were measured. Cells count, total protein, and phospholipids and phospholipases A(2) were determined in the bronchoalveolar lavage (BAL) fluid. Measurements were obtained after the insertion of central lines and 4 hours and 7 hours after the completion of the surgical procedure. Hemodynamic, biochemical, neuromonitoring, and histologic data confirmed the development of liver failure. Seven hours after devascularization, EVLW was higher in AHF (13.7 +/- 1.8 mL/kg) compared with the sham group (5.9 +/- 0.7 mL/kg) (P <.05); in AHF, increase of neutrophils (5% +/- 8% to 25% +/- 8%, P <.001), total protein (6.2 +/- 3.7 to 11.2 +/- 6.5 microg/mL, P <.048), and phospholipase A(2) (1.43 +/- 0.56 to 2.38 +/- 1.38 nmoL/mL/h, P <.03) and decrease in PAF-acetylhydrolase (0.114 +/- 0.128 to 0.039 +/- 0.038 nmol/mL/h, P <.01) compared with baseline were observed; total phospholipids decreased in AHF and increased in the sham model. Histologic examination confirmed lesions compatible with acute lung injury. In conclusion, AHF due to hepatic devascularization induced acute lung injury, confirmed by the increase of inflammatory cells in the alveoli as well as by histologic findings. The decreased PAF-AcH and the increased phospholipase A(2) may play a significant role in the perpetuation of inflammation accompanied by surfactant disorders.

  15. Calcitonin-Induced Effects on Amniotic Fluid-Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Caterina Morabito

    2015-05-01

    Full Text Available Background/Aims: Mesenchymal stem cells from human amniotic fluid (huAFMSCs can differentiate into multiple lineages and are not tumorigenic after transplantation, making them good candidates for therapeutic purposes. The aim was to determine the effects of calcitonin on these huAFMSCs during osteogenic differentiation, in terms of the physiological role of calcitonin in bone homeostasis. Methods: For huAFMSCs cultured under different conditions, we assayed: expression of the calcitonin receptor, using immunolabelling techniques; proliferation and osteogenesis, using colorimetric and enzymatic assays; intracellular Ca2+ and cAMP levels, using videomicroscopy and spectrophotometry. Results: The calcitonin receptor was expressed in proliferating and osteo-differentiated huAFMSCs. Calcitonin triggered intracellular Ca2+ increases and cAMP production. Its presence in cell medium also induced dose-dependent inhibitory effects on proliferation and increased osteogenic differentiation of huAFMSCs, as also indicated by enhancement of specific markers and alkaline phosphatase activity. Conclusions: These data show that huAFMSCs represent a potential osteogenic model to study in-vitro cell responses to calcitonin (and other members of the calcitonin family. This leads the way to the opening of new lines of research that will add new insight both in cell therapies and in the pharmacological use of these molecules.

  16. Fluctuation-induced constraints on the observation of unbinding in a confined complex fluid.

    Science.gov (United States)

    Clarysse, F; Boulter, C J

    2001-07-01

    An extensive study of the effect of fluctuations on the unbinding of an interface from a wall in a ternary system is presented. The framework upon which the analysis is based is a linear functional renormalization group scheme of the appropriate effective interface Hamiltonian. The interface model includes position-dependent gradient coefficients, and their presence is shown to be equivalent to modifications of the bare interface potential that are highly relevant in determining the renormalized critical behavior. We analyze the modified interface potential in a mean-field-like way for both bare critical and first-order unbinding transitions in order to highlight the key effects. We further perform a detailed study of the linearized renormalization group equations identifying three fluctuation regimes and recovering earlier predictions for nonuniversal critical exponents. The surface phase diagram changes dramatically under renormalization with, most notably, fluctuation-induced reentrant behavior. We show that in the revised phase diagram the unbound region is limited in extent indicating that the opportunity for observing an unbinding transition in a confined complex fluid is highly restricted.

  17. Influence of acute fluid loading on stress-induced hemoconcentration and cardiovascular reactivity.

    Science.gov (United States)

    Patterson, Stephen M; VanderKaay, Melissa M; Shanholtzer, Birgit A; Patterson, Cornelia A

    2008-08-01

    The goal of this study was to assess the possible attenuating effects of oral fluid loading on hematological and hemodynamic factors during acute psychological stress in two separate experiments: Experiment 1 assessed the effects of hypotonic fluid loading (water) and Experiment 2 assessed the effects of isotonic fluid loading (Gatorade). Twenty-eight participants were recruited for Experiment 1, and 28 participants were recruited for Experiment 2. Participants for each experiment completed two test sessions, once in a hypo-hydrated condition (following 12-h fast) and once in a fluid loaded condition (hypotonic or isotonic fluid). During each session, hematocrit (Hct), hemoglobin (Hgb), calculated plasma volume (CPV), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR) were assessed during a 10-min resting baseline period, 6-min mental arithmetic (MA) task, and a 16-min recovery period. Results for Experiment 1 revealed that the fluid load condition Hct, Hgb, and HR levels were significantly lower in comparison to the hypo-hydration condition, and that Hct, Hgb, and CPV reactivity was greater during the fluid load condition. Results for Experiment 2 revealed that Hct, Hgb, and TPR were lower and CPV, SBP, SV, and CO were higher during the fluid load condition compared to the hypo-hydration condition and that HR, CO, and TPR reactivity was greater during the fluid load condition. Finally, analytic comparisons between the two fluid types revealed that SV and CO levels were significantly greater at baseline and during MA when isotonic fluid was ingested compared to hypotonic fluid ingestion.

  18. Numerical simulation of blood flow and interstitial fluid pressure in solid tumor microcirculation based on tumor-induced angiogenesis

    Science.gov (United States)

    Zhao, Gaiping; Wu, Jie; Xu, Shixiong; Collins, M. W.; Long, Quan; König, Carola S.; Jiang, Yuping; Wang, Jian; Padhani, A. R.

    2007-10-01

    A coupled intravascular transvascular interstitial fluid flow model is developed to study the distributions of blood flow and interstitial fluid pressure in solid tumor microcirculation based on a tumor-induced microvascular network. This is generated from a 2D nine-point discrete mathematical model of tumor angiogenesis and contains two parent vessels. Blood flow through the microvascular network and interstitial fluid flow in tumor tissues are performed by the extended Poiseuille’s law and Darcy’s law, respectively, transvascular flow is described by Starling’s law; effects of the vascular permeability and the interstitial hydraulic conductivity are also considered. The simulation results predict the heterogeneous blood supply, interstitial hypertension and low convection on the inside of the tumor, which are consistent with physiological observed facts. These results may provide beneficial information for anti-angiogenesis treatment of tumor and further clinical research.

  19. Modeling of fluid injection and withdrawal induced fault activation using discrete element based hydro-mechanical and dynamic coupled simulator

    Science.gov (United States)

    Yoon, Jeoung Seok; Zang, Arno; Zimmermann, Günter; Stephansson, Ove

    2016-04-01

    Operation of fluid injection into and withdrawal from the subsurface for various purposes has been known to induce earthquakes. Such operations include hydraulic fracturing for shale gas extraction, hydraulic stimulation for Enhanced Geothermal System development and waste water disposal. Among these, several damaging earthquakes have been reported in the USA in particular in the areas of high-rate massive amount of wastewater injection [1] mostly with natural fault systems. Oil and gas production have been known to induce earthquake where pore fluid pressure decreases in some cases by several tens of Mega Pascal. One recent seismic event occurred in November 2013 near Azle, Texas where a series of earthquakes began along a mapped ancient fault system [2]. It was studied that a combination of brine production and waste water injection near the fault generated subsurface pressures sufficient to induced earthquakes on near-critically stressed faults. This numerical study aims at investigating the occurrence mechanisms of such earthquakes induced by fluid injection [3] and withdrawal by using hydro-geomechanical coupled dynamic simulator (Itasca's Particle Flow Code 2D). Generic models are setup to investigate the sensitivity of several parameters which include fault orientation, frictional properties, distance from the injection well to the fault, amount of fluid withdrawal around the injection well, to the response of the fault systems and the activation magnitude. Fault slip movement over time in relation to the diffusion of pore pressure is analyzed in detail. Moreover, correlations between the spatial distribution of pore pressure change and the locations of induced seismic events and fault slip rate are investigated. References [1] Keranen KM, Weingarten M, Albers GA, Bekins BA, Ge S, 2014. Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection, Science 345, 448, DOI: 10.1126/science.1255802. [2] Hornbach MJ, DeShon HR

  20. Magnetically Induced "Dry" Water Like Structure of Charged Fluid at the Core of a Magnetar

    CERN Document Server

    Ghosh, S; Ghosh, Sutapa; Chakrabarty, Somenath

    2001-01-01

    It is shown that charged fluid, e.g., electron gas or proton matter at the core of a magnetar exhibit super-fluid (frictionless) like property if the magnetic field strength is high enough to populate only the zeroth Landau levels.

  1. High pressure induced phase transition and superdiffusion in anomalous fluid confined in flexible nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Bordin, José Rafael, E-mail: josebordin@unipampa.edu.br [Campus Caçapava do Sul, Universidade Federal do Pampa, Caixa Postal 15051, CEP 96570-000, Caçapava do Sul, RS (Brazil); Krott, Leandro B., E-mail: leandro.krott@ufrgs.br; Barbosa, Marcia C., E-mail: marcia.barbosa@ufrgs.br [Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2014-10-14

    The behavior of a confined spherical symmetric anomalous fluid under high external pressure was studied with Molecular Dynamics simulations. The fluid is modeled by a core-softened potential with two characteristic length scales, which in bulk reproduces the dynamical, thermodynamical, and structural anomalous behavior observed for water and other anomalous fluids. Our findings show that this system has a superdiffusion regime for sufficient high pressure and low temperature. As well, our results indicate that this superdiffusive regime is strongly related with the fluid structural properties and the superdiffusion to diffusion transition is a first order phase transition. We show how the simulation time and statistics are important to obtain the correct dynamical behavior of the confined fluid. Our results are discussed on the basis of the two length scales.

  2. Thermoelastic stresses induced by non-isothermal fluid injection into fractured rock

    Science.gov (United States)

    Mossop, A.; Matthai, S. K.

    2003-04-01

    The injection of cold water into hot fractured rock occurs in a number of industrial scenarios, most commonly in the recharge of geothermal reservoirs and during waterflood operations in hydrocarbon reservoirs. The cold water cools the rock local to the fracture flow pathways, the cooled rock contracts, causing localised stress perturbations. Essentially analogous physical processes are involved in the injection of hot fluids into cooler rock such as occur in steam flood operations in viscous oil recovery. In this study we investigate such thermoelastic stresses induced by non-isothermal injection into a three dimensional fractured rock mass. The starting point of our analysis is an idealized model of injection into a single, uniform, horizontal fracture. For this case we have previously found semi-analytic solutions and analytic estimates of the stress perturbation and these are in turn used for cross-verification of an isoparametric, quadratic, finite element model of the system. In the numerical model the fractures are treated as discrete conductive channels within the matrix and an additional feature is that the matrix itself can be assigned a non-zero permeability. As the numerical simulator follows a fundamentally different methodology for solving these thermoelastic problems, the results help to validate some of the scaling relationships and non-intuitive behaviour deduced from the analytic estimates (e.g. for a broad range of flow rates, fracture normal stress perturbations decrease with increasing injection rates). The finite element model is then used to explore progressively more complex fracture geometries and networks. Finally we investigate the validity of a continuum limit as fracture densities increase to the point that fracture separation length scales are comparable with thermal diffusion length scales.

  3. Phase mixing induced by granular fluid pump during mantle strain localization

    Science.gov (United States)

    Précigout, Jacques; Prigent, Cécile; Palasse, Laurie; Pochon, Anthony

    2014-05-01

    Mantle viscous strain localization is often attributed to feedbacks between grain boundary sliding (GBS) and phase mixing, as GBS could promote mixing through grain switching, and phase mixing would enhance grain-size-sensitive granular flow through grain boundary pinning. However, although GBS and phase mixing are intimately related, recent data show that GBS alone cannot end-up with randomly mixed phases. Here we show natural observations of an ultramylonitic shear zone from the Ronda peridotite (Spain) where both GBS and phase mixing occur. Microprobe analyses and coupled EDX/EBSD data first document enrichment in pyroxenes and amphibole concomitant with both phase mixing and complete randomization of the olivine fabric in fine-grained layers (5-20 microns) where strain has been localized. Both the fabric randomization and some microstructural observations indicate that these layers mostly deformed by granular flow, i.e., by GBS. Based on petrological pseudo-sections, we also show that phase enrichment does not result from metamorphic reaction, but instead from dissolution-precipitation phenomena. Finally, we document in adjacent areas a change of olivine fabric geometry that highlights syn-tectonic water draining towards fine-grained layers. While olivine fabric switches from E-type (moderately hydrated fabric) to C-type (highly hydrated fabric) towards fine-grained layers, it changes from E-type to D-type (highly hydrated fabric) in coarse-grained bands between E/C-type layers. Altogether, our findings suggest that water converges as a result of GBS-induced creep cavitation and subsequent granular fluid pump in fine-grained layers. We propose that phase mixing originates here from such a creep cavitation through dissolution-precipitation of secondary phases in newly formed cavities, giving rise to a key process for the relationships between GBS and phase mixing, and hence, for the origin of viscous strain localization in the upper mantle.

  4. Pluripotency can be rapidly and efficiently induced in human amniotic fluid-derived cells.

    Science.gov (United States)

    Li, Chunliang; Zhou, Junmei; Shi, Guilai; Ma, Yu; Yang, Ying; Gu, Junjie; Yu, Hongyao; Jin, Shibo; Wei, Zhe; Chen, Fang; Jin, Ying

    2009-11-15

    Direct reprogramming of human somatic cells into pluripotency has broad implications in generating patient-specific induced pluripotent stem (iPS) cells for disease modeling and cellular replacement therapies. However, the low efficiency and safety issues associated with generation of human iPS cells have limited their usage in clinical settings. Cell types can significantly influence reprogramming efficiency and kinetics. To date, human iPS cells have been obtained only from a few cell types. Here, we report for the first time rapid and efficient generation of iPS cells from human amniotic fluid-derived cells (hAFDCs) via ectopic expression of four human factors: OCT4/SOX2/KLF4/C-MYC. Significantly, typical single iPS cell colonies can be picked up 6 days after viral infection with high efficiency. Eight iPS cell lines have been derived. They can be continuously propagated in vitro and express pluripotency markers such as AKP, OCT4, SOX2, SSEA4, TRA-1-60 and TRA-1-81, maintaining the normal karyotype. Transgenes are completely inactivated and the endogenous OCT4 promoter is adequately demethylated in the established iPS cell lines. Moreover, various cells and tissues from all three germ layers are found in embryoid bodies and teratomas, respectively. In addition, microarray analysis demonstrates a high correlation coefficient between hAFDC-iPS cells and human embryonic stem cells, but a low correlation coefficient between hAFDCs and hAFDC-iPS cells. Taken together, these data identify an ideal human somatic cell resource for rapid and efficient generation of iPS cells, allowing us to establish human iPS cells using more advanced approaches and possibly to establish disease- or patient-specific iPS cells.

  5. Progressive multiple sclerosis cerebrospinal fluid induces inflammatory demyelination, axonal loss, and astrogliosis in mice.

    Science.gov (United States)

    Cristofanilli, Massimiliano; Rosenthal, Hannah; Cymring, Barbara; Gratch, Daniel; Pagano, Benjamin; Xie, Boxun; Sadiq, Saud A

    2014-11-01

    Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory demyelination and neurodegeneration throughout the CNS, which lead over time to a condition of irreversible functional decline known as progressive MS. Currently, there are no satisfactory treatments for this condition because the mechanisms that underlie disease progression are not well understood. This is partly due to the lack of a specific animal model that represents progressive MS. We investigated the effects of intracerebroventricular injections of cerebrospinal fluid (CSF) derived from untreated primary progressive (PPMS), secondary progressive (SPMS), and relapsing/remitting (RRMS) MS patients into mice. We found discrete inflammatory demyelinating lesions containing macrophages, B cell and T cell infiltrates in the brains of animals injected with CSF from patients with progressive MS. These lesions were rarely found in animals injected with RRMS-CSF and never in those treated with control-CSF. Animals that developed brain lesions also presented extensive inflammation in their spinal cord. However, discrete spinal cord lesions were rare and only seen in animals injected with PPMS-CSF. Axonal loss and astrogliosis were seen within the lesions following the initial demyelination. In addition, Th17 cell activity was enhanced in the CNS and in lymph nodes of progressive MS-CSF injected animals compared to controls. Furthermore, CSF derived from MS patients who were clinically stable following therapy had greatly diminished capacity to induce CNS lesions in mice. Finally, we provided evidence suggesting that differential expression of pro-inflammatory cytokines present in the progressive MS CSF might be involved in the observed mouse pathology. Our data suggests that the agent(s) responsible for the demyelination and neurodegeneration characteristic of progressive MS is present in patient CSF and is amenable to further characterization in experimental models of the disease.

  6. CFD simulations of flow erosion and flow-induced deformation of needle valve: Effects of operation, structure and fluid parameters

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongjun, E-mail: ticky863@126.com [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan (China); State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, Sichuan (China); Pan, Qian; Zhang, Wenli; Feng, Guang; Li, Xue [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan (China)

    2014-07-01

    Highlights: • A combined FSI–CFD and DPM computational method is used to investigate flow erosion and deformation of needle valve. • The numerical model is validated with the comparison of measured and predicted erosion rate. • Effects of operation, structure and fluid parameters on flow erosion and flow-induced deformation are discussed. • Particle diameter has the most significant effect on flow erosion. • Inlet rate has the most obvious effect on flow-induced deformation. - Abstract: A three-dimensional fluid–structure interaction (FSI) computational model coupling with a combined continuum and discrete model has been used to predict the flow erosion rate and flow-induced deformation of needle valve. Comparisons with measured data demonstrate good agreement with the predictions of erosion rate. The flow field distribution of gas-particle flow and the erosion rate and deformation of valve core are captured under different operating and structural conditions with different fluid parameters. The effects of inlet velocity, valve opening and inlet valve channel size, particle concentration, particle diameter and particle phase components are discussed in detail. The results indicate that valve tip has the most severe erosion and deformation, and flow field, erosion rate and deformation of valve are all sensitive to inlet condition changes, structural changes and fluid properties changes. The effect of particle diameter on erosion is the most significant, while the influence of inlet rate on deformation is the greatest one.

  7. Reaction-induced grain boundary cracking and anisotropic fluid flow during prograde devolatilization reactions within subduction zones

    Science.gov (United States)

    Okamoto, Atsushi; Shimizu, Hiroyuki; Fukuda, Jun-ichi; Muto, Jun; Okudaira, Takamoto

    2017-09-01

    Devolatilization reactions during prograde metamorphism are a key control on the fluid distribution within subduction zones. Garnets in Mn-rich quartz schist within the Sanbagawa metamorphic belt of Japan are characterized by skeletal structures containing abundant quartz inclusions. Each quartz inclusion was angular-shaped, and showed random crystallographic orientations, suggesting that these quartz inclusions were trapped via grain boundary cracking during garnet growth. Such skeletal garnet within the quartz schist formed related to decarbonation reactions with a positive total volume change (Δ V t > 0), whereas the euhedral garnet within the pelitic schists formed as a result of dehydration reaction with negative Δ V t values. Coupled hydrological-chemical-mechanical processes during metamorphic devolatilization reactions were investigated by a distinct element method (DEM) numerical simulation on a foliated rock that contained reactive minerals and non-reactive matrix minerals. Negative Δ V t reactions cause a decrease in fluid pressure and do not produce fractures within the matrix. In contrast, a fluid pressure increase by positive Δ V t reactions results in hydrofracturing of the matrix. This fracturing preferentially occurs along grain boundaries and causes episodic fluid pulses associated with the development of the fracture network. The precipitation of garnet within grain boundary fractures could explain the formation of the skeletal garnet. Our DEM model also suggests a strong influence of reaction-induced fracturing on anisotropic fluid flow, meaning that dominant fluid flow directions could easily change in response to changes in stress configuration and the magnitude of differential stress during prograde metamorphism within a subduction zone.

  8. Spontaneous mirror-symmetry breaking induces inverse energy cascade in 3D active fluids

    CERN Document Server

    Słomka, Jonasz

    2016-01-01

    Classical turbulence theory assumes that energy transport in a 3D turbulent flow proceeds through a Richardson cascade whereby larger vortices successively decay into smaller ones. By contrast, an additional inverse cascade characterized by vortex-mergers exists in 2D fluids and gases, with profound implications for meteorological flows and fluid mixing. The possibility of a helicity-driven inverse cascade in 3D fluids had been rejected in the 1970s based on equilibrium-thermodynamic arguments. Recently, however, it was proposed that certain symmetry breaking processes could potentially trigger a 3D inverse cascade, but no physical system exhibiting this phenomenon has been identified to date. Here, we present direct analytical and numerical evidence for the existence of a robust inverse energy cascade in an experimentally validated 3D active fluid model, describing microbial suspension flows that spontaneously break mirror-symmetry. We show analytically that self-organized scale selection, a generic feature ...

  9. MECHANISMS OF FLUID SHEAR-INDUCED INHIBITION OF POPULATION GROWTH IN A RED-TIDE DINOFLAGELLATE

    Science.gov (United States)

    Net population growth of some dinoflagellates is inhibited by fluid shear at shear stresses comparable with those generated during oceanic turbulence. Decreased net growth may occur through lowered cell division, increased mortality, or both. The dominant mechanism under various ...

  10. Induced Seismicity Associated with Waste Fluid Injection into Deep Wells in Youngstown, Ohio

    Science.gov (United States)

    Kim, W.

    2012-12-01

    Since March 2011, residents in Youngstown, Ohio area experienced small earthquakes (M ~2.5). By 25 November 2011, about a dozen small but felt earthquakes have occurred around Youngstown. On 1 Dec. 2011 four portable seismographs were deployed around the epicentral area to monitor seismicity at close distances and determine hypocenters of the small earthquakes accurately, because these shocks were occurring close to a deep waste fluid injection well that began injection operation on 28 Dec. 2010. On 24 December 2011, a magnitude 2.7 shock occurred in the epicentral area which was accurately located by using the portable station data. The 24 Dec. shock is located about 800 m from the injection well and at a depth of 3.5 km, suggesting that those earthquakes in Youngstown could have been induced by the deep well injection operation. Hence, the injection was stopped on 30 Dec. 2011. However, the largest earthquake in the sequence (M4.0) occurred on 31 December 2011 within about 24 hours from halting injection operation. A total of 196 shocks are recorded during Dec. 2011 - April 2012. These shocks occurred as three distinct clusters of events, and a swarm of 82 small events. Three clusters of shocks have occurred in the narrow depth range (3.5-3.9 km) and the clusters appear to be on parallel faults of similar orientation offset by about 200-300 m apart. The swarm of small shocks (M -0.3 - 0.1) have occurred on 18 Feb. 2012 and lasted only few hours (12:36-15:46). These swarm events all lie in a very small region with depth range 3.8-4.2 km. The Precambrian basement rock in the region is at a depth 2.7 km, and hence all the shocks have occurred within in the Precambrian basement. Focal mechanism of the main shock is predominantly strike-slip faulting along steeply dipping nodal planes. The orientation of the WSW striking nodal plane (265 degree) is consistent with the lineation of the main cluster of shocks that include well-located main shock and other two largest

  11. A Comparison of the Mechanisms of Cold- and Microgravity-Induced Fluid Loss.

    Science.gov (United States)

    1989-08-10

    endpoint of fluid and electrolyte loss through diuresis and natriuresis . Differences in the responses were also noted, although the data necessary to...SUBJECT TERMS (Continue on reverse if necessarynd..iien.nti., by c blo i("nunber ,. FIELD GROUP SUB-GROUP cold, diuresis , microgravity,-w•_ightlessness...rff’dentify by block number)cC The physiological mechanisms involved in the diuresis and overall fluid loss associated with exposure to cold or microgravity

  12. Flow non-normality-induced transient growth in superposed Newtonian and non-Newtonian fluid layers

    OpenAIRE

    Ridolfi, Luca; Camporeale, Carlo Vincenzo

    2009-01-01

    In recent years non-normality and transient growths have attracted much interest in fluid mechanics. Here, we investigate these topics with reference to the problem of interfacial instability in superposed Newtonian and non-Newtonian fluid layers. Under the hypothesis of the lubrication theory, we demonstrate the existence of significant transient growths in the parameter space region where the dynamical system is asymptotically stable, and show how they depend on the main physical parameters...

  13. Hydromagnetic Blood Flow of Sisko Fluid in a Non-uniform Channel Induced by Peristaltic Wave

    Science.gov (United States)

    Zeeshan, A.; Bhatti, M. M.; Akbar, N. S.; Sajjad, Y.

    2017-07-01

    In this paper, a smooth repetitive oscillating wave traveling down the elastic walls of a non-uniform two-dimensional channels is considered. It is assumed that the fluid is electrically conducting and a uniform magnetic field is perpendicular to flow. The Sisko fluid is grease thick non-Newtonian fluid can be considered equivalent to blood. Taking long wavelength and low Reynolds number, the equations are reduced. The analytical solution of the emerging non-linear differential equation is obtained by employing Homotopy Perturbation Method (HPM). The outcomes for dimensionless flow rate and dimensionless pressure rise have been computed numerically with respect to sundry concerning parameters amplitude ratio ϕ, Hartmann number M, and Sisko fluid parameter b 1. The behaviors for pressure rise and average friction have been discussed in details and displayed graphically. Numerical and graphical comparison of Newtonian and non-Newtonian has also been evaluated for velocity and pressure rise. It is observed that the magnitude of pressure rise is maximum in the middle of the channel whereas for higher values of fluid parameter it increases. Further, it is also found that the velocity profile shows converse behavior along the walls of the channel against multiple values of fluid parameter.

  14. Metabolomic changes in follicular fluid induced by soy isoflavones administered to rats from weaning until sexual maturity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxiang [Department of Nutrition and Health Care, School of Public Health, Fujian Medical University, Fuzhou, Fujian (China); Zhang, Wenchang, E-mail: wenchang2002@sina.com [Department of Occupational and Environmental Health, School of Public Health, Fujian Medical University, Fuzhou, Fujian (China); Liu, Jin [Department of Occupational and Environmental Health, School of Public Health, Fujian Medical University, Fuzhou, Fujian (China); Sun, Yan [Center for Reproductive Medicine, Teaching Hospital of Fujian Medical University, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian (China); Li, Yuchen; Li, Hong; Xiao, Shihua; Shen, Xiaohua [Department of Occupational and Environmental Health, School of Public Health, Fujian Medical University, Fuzhou, Fujian (China)

    2013-06-15

    Female Wistar rats at 21 days of age were treated with one of three concentrations of soy isoflavones (SIF) (50, 100 or 200 mg/kg body weight, orally, once per day) from weaning until sexual maturity (3 months) in order to evaluate the influence of SIF on ovarian follicle development. After treatment, the serum sex hormone levels and enumeration of ovarian follicles of the ovary were measured. The metabolic profile of follicular fluid was determined using HPLC-MS. Principal component analysis (PCA) and partial least-squares-discriminant analysis (PLS-DA) was used to identify differences in metabolites and reveal useful toxic biomarkers. The results indicated that modest doses of SIF affect ovarian follicle development, as demonstrated by decreased serum estradiol levels and increases in both ovarian follicle atresia and corpora lutea number in the ovary. SIF treatment-related metabolic alterations in follicular fluid were also found in the PCA and PLS-DA models. The 24 most significantly altered metabolites were identified, including primary sex hormones, amino acids, fatty acids and metabolites involved in energy metabolism. These findings may indicate that soy isoflavones affect ovarian follicle development by inducing metabolomic variations in the follicular fluid. - Highlights: ► Modest doses of soy isoflavones (SIF) do affect ovarian follicle development. ► SIF treatment-related metabolic alterations in follicular fluid were found. ► The 24 most significantly altered metabolites were identified.

  15. Stimulation of mating-induced uterine contractions in the bitch and their modification and enhancement of fertility by prostatic fluid.

    Science.gov (United States)

    England, G C W; Moxon, R; Freeman, S L

    2012-12-01

    Little is known about the response of the bitch's reproductive tract to mating or of the role of male accessory gland secretions in the female. In this clinical study, the component stimuli causing mating-induced uterine contractions were investigated in 64 bitches. Basal uterine contractions were present during oestrus and a significant increase in the frequency of contractions was observed during natural mating. Neither teasing with a male nor stimulation of the vagina or cervix by vaginal or transcervical insemination (TCI) caused an increase in the frequency of uterine contractions. Increased contractions were however present after both vaginal and transcervical insemination when the vestibule was distended, and dorsal wall of the vaginal was manually stimulated. Interestingly, this increase in uterine contractions was partially ameliorated when prostatic fluid was used as a flushing component following transcervical insemination. Two further studies performed with 72 bitches of which 18 were each inseminated transcervically with fresh or frozen semen flushed into the uterus with either saline or prostatic fluid demonstrated that prostatic fluid significantly increased the pregnancy rate and litter size of both groups. There are important mechanisms regulating the transport and elimination of sperm from the bitch's reproductive tract. Whilst physical aspects of coitus are undoubtedly involved in initiating uterine contractions, prostatic fluid appears to have an important role in modulating uterine contractions and fertility.

  16. Effects of rotation and initial stress on peristaltic transport of fourth grade fluid with heat transfer and induced magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Alla, A.M., E-mail: mohmrr@yahoo.com [Mathematics Department, Faculty of Science, Taif University (Saudi Arabia); Mathematics Department, Faculty of Science, Sohag (Egypt); Abo-Dahab, S.M., E-mail: sdahb@yahoo.com [Mathematics Department, Faculty of Science, Taif University (Saudi Arabia); Mathematics Department, Faculty of Science, SVU, Qena 83523 (Egypt); El-Shahrany, H.D. [Mathematics Department, Faculty of Science, Taif University (Saudi Arabia)

    2014-01-15

    This paper investigates the effect of rotation and initial stress on the peristaltic flow of an incompressible fourth grade fluid in asymmetric channel with magnetic field and heat transfer. Constitutive equations obeying the fourth grade fluid model are employed. Assumptions of long wavelength and low Reynolds number are used in deriving solution for the flow. Closed form expressions for the stream function, pressure gradient, temperature, magnetic force function, induced magnetic field and current density are developed. Pressure rise per wavelength and frictional forces on the channel walls have been computed numerically. Effects of rotation, initial stress and inclination of magnetic field on the axial velocity and pressure gradient are discussed in detail and shown graphically. Several limiting results can be obtained as the special cases of the problem under consideration. Numerical illustrations that show the physical effects and the pertinent features are investigated at the end of the paper. - Highlights: • Effect of rotation, magnetic field, heat transfer and initial stress on the peristaltic flow of an incompressible fourth grade fluid. • Assumptions of long wavelength and low Reynolds number are used in deriving solution for the flow. • Closed form expressions for the stream function, pressure gradient, temperature, magnetic force function, induced magnetic field and current density.

  17. Fluid induced microstructures in granulites from the Reynolds Range, central Australia

    Science.gov (United States)

    Prent, Alexander; Beinlich, Andreas; Raimondo, Tom; Putnis, Andrew

    2016-04-01

    Fluids play a major role in the evolution of the Earth's crust, driving metamorphic reactions, facilitating transport of mass and heat, and changing the physical properties of rock. Shear zones present in intraplate orogens are ideal natural laboratories to study the relationship of fluid-driven rock weakening to deformation, and thus the impact of fluid availability on the tectonic reworking of continental interiors. Here we present preliminary observations from the Aileron Shear Zone (ASZ), Reynolds Range, central Australia, a major crustal-scale thrust of the Palaeozoic Alice Springs Orogen (ASO). This study focuses on the effects of fluids on the mineralogy and mineral chemistry of deep crustal rocks collected from a transect running through the ASZ. The ASZ is thought to have been of major importance during exhumation of the ASO, and exhumes a partly retrogressed suite of felsic and metasedimentary granulite facies gneisses. Hydration reactions associated with retrogression resulted in the partial replacement of orthopyroxene and numerous myrmekite textures associated with plagioclase and mica. In undeformed samples, orthopyroxene (En56 Fer44) rims are partly replaced by a zoned sequence of biotite (Phl70 Ann30), sub-parallel rims of magnetite, biotite and K-feldspar (Or87). Deformed samples gradually show an increase in dynamic recrystallization of quartz, with fully recrystallized bands of foam texture quartz defining the foliation together with biotite. Quartz and minor biotite replacement then dominates the mineral assemblage with increasing strain. The presence of fluid-driven mineral replacement reactions in undeformed samples suggests that hydration predates shearing and exhumation, and furthermore, that strain may have been localised in areas of intense hydration and rock weakening. Retrograde reactions and myrmekite textures suggest the availability of a silica-saturated fluid. Additional mass-balance calculations will be applied to constrain the

  18. Mechanical instability induced by water weakening in laboratory fluid injection tests

    Science.gov (United States)

    David, C.; Dautriat, J.; Sarout, J.; Delle Piane, C.; Menéndez, B.; Macault, R.; Bertauld, D.

    2015-06-01

    To assess water-weakening effects in reservoir rocks, previous experimental studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks fully saturated either with water or with inert fluids. So far, little attention has been paid to the mechanical behavior during fluid injection under conditions similar to enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behavior of the weakly consolidated Sherwood sandstone in laboratory experiments. Our specimens were instrumented with 16 ultrasonic P wave transducers for both passive and active acoustic monitoring during loading and fluid injection to record the acoustic signature of fluid migration in the pore space and the development of damage. Calibration triaxial tests were conducted on three samples saturated with air, water, or oil. In a second series of experiments, water and inert oil were injected into samples critically loaded up to 80% or 70% of the dry or oil-saturated compressive strength, respectively, to assess the impact of fluid migration on mechanical strength and elastic properties. The fluids were injected with a low back pressure to minimize effective stress variations during injection. Our observations show that creep takes place with a much higher strain rate for water injection compared to oil injection. The most remarkable difference is that water injection in both dry and oil-saturated samples triggers mechanical instability (macroscopic failure) within half an hour whereas oil injection does not after several hours. The analysis of X-ray computed tomography images of postmortem samples revealed that the mechanical instability was probably linked to loss of cohesion in the water-invaded region.

  19. Effect of Phenylephrine on Alveolar Fluid Clearance in Ventilator-induced Lung Injury

    Institute of Scientific and Technical Information of China (English)

    Nai-jing Li; Xiu Gu; Wei Li; Yan Li; Sheng-qi Li; Ping He

    2013-01-01

    Objective To investigate the effect of phenylephrine (an α-adrenergic agonist) on alveolar fluid clearance (AFC) in ventilator-induced lung injury and the possible mechanism involved. Methods A total of 170 male Wistar rats were randomly allocated into 17 groups (n=10) using ran-dom number tables. Short-term (40 minutes) mechanical ventilation with high tidal volume (HVT) was per-formed to induce lung injury,impair active Na+ transport and lung liquid clearance in the rats. Unventilated rats served as controls. To demonstrate the effect of phenylephrine on AFC,phenylephrine at different con-centrations (1×10-5,1×10-6,1×10-7,1×10-8,and 1×10-9 mol/L) was injected into the alveolar space of the HVT ventilated rats. To identify the influence of adrenergic antagonists,Na+ channel,and microtubular sys-tem on the effect of phenylephrine,phenylephrine at 1×10-5 mol/L combined with prazosin (an α1-adrener-gic antagonist,1×10-4 mol/L),yohimbine (an α2-adrenergic antagonist,1×10-4 mol/L),atenolol (a β1-adrenergic antagonist,1×10-5 mol/L),ICI-118551 (an β2-adrenergic antagonist,1×10-5 mol/L),amiloride (a Na+ channel blocker,5×10-4 mol/L),ouabain (a Na+/K+-ATPase blocker,5×10-4 mol/L),colchicine (a mi-crotubular disrupting agent,0.25 mg/100 g body weight),or β-lumicolchicine (an isomer of colchicine,0.25 mg/100 g body weight) were perfused into the alveolar space of the rats ventilated with HVT for 40 minutes. AFC and total lung water content were measured. Results Basal AFC in control rats was (17.47±2.56)%/hour,which decreased to (9.64± 1.32)%/hour in HVT ventilated rats (P=0.003). The perfusion of phenylephrine at 1×10-8,1×10-7,1×10-6,and 1×10-5 mol/L significantly increased the AFC in HVT ventilated rats (all P<0.05). This effect of phenylephrine on AFC was suppressed by prazosin,atenolol,and ICI-118551 in HVT ventilated rats by 53%,31%,and 37%,respectively (all P<0.05). The AFC-stimulating effect of phenylephrine was lowered by 33% and 42% with

  20. Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid

    Energy Technology Data Exchange (ETDEWEB)

    Jellinck, P.H.; Newbold, R.R.; McLachlan, J.A. (Queen' s University, Kingston, Ontario (Canada))

    1991-04-01

    Peroxidase activity in the uterine luminal fluid of mice treated with diethylstilbestrol was measured by the guaiacol assay and also by the formation of 3H2O from (2-3H)estradiol. In the radiometric assay, the generation of 3H2O and 3H-labeled water-soluble products was dependent on H2O2 (25 to 100 microM), with higher concentrations being inhibitory. Tyrosine or 2,4-dichlorophenol strongly enhanced the reaction catalyzed either by the luminal fluid peroxidase or the enzyme in the CaCl2 extract of the uterus, but decreased the formation of 3H2O from (2-3H)estradiol by lactoperoxidase in the presence of H2O2 (80 microM). NADPH, ascorbate, and cytochrome c inhibited both luminal fluid and uterine tissue peroxidase activity to the same extent, while superoxide dismutase showed a marginal activating effect. Lactoferrin, a major protein component of uterine luminal fluid, was shown not to contribute to its peroxidative activity, and such an effect by prostaglandin synthase was also ruled out. However, it was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of peroxidase activity in uterine luminal fluid.

  1. Effects of rotation and initial stress on peristaltic transport of fourth grade fluid with heat transfer and induced magnetic field

    Science.gov (United States)

    Abd-Alla, A. M.; Abo-Dahab, S. M.; El-Shahrany, H. D.

    2014-01-01

    This paper investigates the effect of rotation and initial stress on the peristaltic flow of an incompressible fourth grade fluid in asymmetric channel with magnetic field and heat transfer. Constitutive equations obeying the fourth grade fluid model are employed. Assumptions of long wavelength and low Reynolds number are used in deriving solution for the flow. Closed form expressions for the stream function, pressure gradient, temperature, magnetic force function, induced magnetic field and current density are developed. Pressure rise per wavelength and frictional forces on the channel walls have been computed numerically. Effects of rotation, initial stress and inclination of magnetic field on the axial velocity and pressure gradient are discussed in detail and shown graphically. Several limiting results can be obtained as the special cases of the problem under consideration. Numerical illustrations that show the physical effects and the pertinent features are investigated at the end of the paper.

  2. Fluid shear stress inhibits TNF-alpha-induced apoptosis in osteoblasts: a role for fluid shear stress-induced activation of PI3-kinase and inhibition of caspase-3

    Science.gov (United States)

    Pavalko, Fredrick M.; Gerard, Rita L.; Ponik, Suzanne M.; Gallagher, Patricia J.; Jin, Yijun; Norvell, Suzanne M.

    2003-01-01

    In bone, a large proportion of osteoblasts, the cells responsible for deposition of new bone, normally undergo programmed cell death (apoptosis). Because mechanical loading of bone increases the rate of new bone formation, we hypothesized that mechanical stimulation of osteoblasts might increase their survival. To test this hypothesis, we investigated the effects of fluid shear stress (FSS) on osteoblast apoptosis using three osteoblast cell types: primary rat calvarial osteoblasts (RCOB), MC3T3-E1 osteoblastic cells, and UMR106 osteosarcoma cells. Cells were treated with TNF-alpha in the presence of cyclohexamide (CHX) to rapidly induce apoptosis. Osteoblasts showed significant signs of apoptosis within 4-6 h of exposure to TNF-alpha and CHX, and application of FSS (12 dyne/cm(2)) significantly attenuated this TNF-alpha-induced apoptosis. FSS activated PI3-kinase signaling, induced phosphorylation of Akt, and inhibited TNF-alpha-induced activation of caspase-3. Inhibition of PI3-kinase, using LY294002, blocked the ability of FSS to rescue osteoblasts from TNF-alpha-induced apoptosis and blocked FSS-induced inhibition of caspase-3 activation in osteoblasts treated with TNF-alpha. LY294002 did not, however, prevent FSS-induced phosphorylation of Akt suggesting that activation of Akt alone is not sufficient to rescue cells from apoptosis. This result also suggests that FSS can activate Akt via a PI3-kinase-independent pathway. These studies demonstrate for the first time that application of FSS to osteoblasts in vitro results in inhibition of TNF-alpha-induced apoptosis through a mechanism involving activation of PI3-kinase signaling and inhibition of caspases. FSS-induced activation of PI3-kinase may promote cell survival through a mechanism that is distinct from the Akt-mediated survival pathway. Copyright 2002 Wiley-Liss, Inc.

  3. Flow of a Burger’s Fluid in a Channel Induced by Peristaltic Compliant Walls

    Directory of Open Access Journals (Sweden)

    I. Ahmad

    2014-01-01

    Full Text Available A theoretical analysis is presented for the peristaltic motion of a magneto-hydrodynamic (MHD non-Newtonian fluid in channel with complaint walls. The fluid obeys viscoelastic non-Newtonian model with Burger’s constitutive equation. The relevant equations are first developed and then solved using perturbation technique. Expressions of stream function and velocity components are constructed under the assumption that δ (characteristic ratio of transversal and axial scales of peristaltic motion is small. The results indicate the strong effects of Burger’s fluid parameter, Hartman number, Reynolds number, and complaint wall parameters on the velocity field and stream function. The obtained solutions are shown graphically for the different values of involved parameters.

  4. Numerical Analysis of Hydrodynamic Pressure Induced by Fluid-Solid Impact

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    - As a further development of the authors′ work (Huang and Qian, 1993), in this paper a newnumerical method based on the time domain boundary element technique is proposed for solving fluid-sol-id coupling problems, in which a rigid body impacts normally on the calm surface of a half-space fluid. Afundamental solution to the half-space potential flow problem is first derived with the method of images.Then, an equivalent boundary integral equation in the Laplace transform domain is established by meansof Green′s second identity. Through the inverse Laplace transform and discretization in both time andboundary of the fluid region, the numerical calculation for the problem under consideration has been car-ried out. Several examples demonstrate that the present method is more efficient than existing ones, fromwhich it is also seen that the shape of the impacting body has a considerable effect on the total impactforce.

  5. Theory of wetting-induced fluid entrainment by advancing contact lines on dry surfaces.

    Science.gov (United States)

    Ledesma-Aguilar, R; Hernández-Machado, A; Pagonabarraga, I

    2013-06-28

    We report on the onset of fluid entrainment when a contact line is forced to advance over a dry solid of arbitrary wettability. We show that entrainment occurs at a critical advancing speed beyond which the balance between capillary, viscous, and contact-line forces sustaining the shape of the interface is no longer satisfied. Wetting couples to the hydrodynamics by setting both the morphology of the interface at small scales and the viscous friction of the front. We find that the critical deformation that the interface can sustain is controlled by the friction at the contact line and the viscosity contrast between the displacing and displaced fluids, leading to a rich variety of wetting-entrainment regimes. We discuss the potential use of our theory to measure contact-line forces using atomic force microscopy and to study entrainment under microfluidic conditions exploiting colloid-polymer fluids of ultralow surface tension.

  6. Heat transfer analysis on peristaltically induced motion of particle-fluid suspension with variable viscosity: Clot blood model.

    Science.gov (United States)

    Bhatti, M M; Zeeshan, A; Ellahi, R

    2016-12-01

    In this article, heat transfer analysis on clot blood model of the particle-fluid suspension through a non-uniform annulus has been investigated. The blood propagating along the whole length of the annulus was induced by peristaltic motion. The effects of variable viscosity and slip condition are also taken into account. The governing flow problem is modeled using lubrication approach by taking the assumption of long wavelength and creeping flow regime. The resulting equation for fluid phase and particle phase is solved analytically and closed form solutions are obtained. The physical impact of all the emerging parameters is discussed mathematically and graphically. Particularly, we considered the effects of particle volume fraction, slip parameter, the maximum height of clot, viscosity parameter, average volume flow rate, Prandtl number, Eckert number and fluid parameter on temperature profile, pressure rise and friction forces for outer and inner tube. Numerical computations have been used to determine the behavior of pressure rise and friction along the whole length of the annulus. The present study is also presented for an endoscope as a special case of our study. It is observed that greater influence of clot tends to rise the pressure rise significantly. It is also found that temperature profile increases due to the enhancement in Prandtl number, Eckert number, and fluid parameter. The present study reveals that friction forces for outer tube have higher magnitude as compared to the friction forces for an inner tube. In fact, the results for present study can also be reduced to the Newtonian fluid by taking ζ → ∞.

  7. A case study of waste fluid injection and induced seismicity in the Raton Basin, Trinidad, CO, USA

    Science.gov (United States)

    Weingarten, M. B.; Ge, S.

    2012-12-01

    Waste fluid injection into rock formations has been speculated to cause seismicity. This study analyzed the link between the injection of fluid waste from coal-bed methane production and recent earthquakes swarms around the town of Trinidad, Colorado, USA. The study area is in a relatively quiescent intraplate zone, located in the Mesozoic sedimentary formations of the Raton Basin. Since 1999, when waste fluid injection began in the vicinity of Trinidad, more than 175 earthquakes of greater than M2.5 have occurred, representing a more than 30-fold increase in the number of earthquakes as compared with the previous 3 decades. The vast majority of earthquake epicenters are located within 5 km of one of the 24 injection wells. Two years after waste fluid injection began, an earthquake swarm occurred on a NE-trending fault structure, but a causal relationship between the fluid injection and swarm could not be definitively made. Earthquakes and injection continued and, in 2011, another earthquake swarm occurred, possibly reactivating the same NE-trending fault structure. Due to the lack of robust spatial seismometer coverage, earthquake hypocentral depths often have significant uncertainties, but could be at depths co-located with injection depths. The link between fluid waste injection and seismicity is characterized by spatial and temporal correlations as well as pore pressure changes sufficient to induce seismicity at depth. Pore pressure calculations were performed using a two-dimensional analytical solution for a homogeneous and isotropic aquifer with a hydraulic conductivity of 1.0x10^-7 m/s and storage coefficient of 5.0x10^-5. Reservoir model parameters are representative of the Dakota Sandstone, a fluvial and conglomeratic sandstone sequence, which is the dominant formation for injection. Computed pressure buildup in the aquifer was correlated spatially and temporally to earthquake epicenters. Preliminary results suggest that pore pressure changes in the

  8. Experimental study of electron beam induced removal of H/sub 2/S from geothermal fluids

    Energy Technology Data Exchange (ETDEWEB)

    Helfritch, D.J.; Singhvi, R.; Evans, R.D.; Reynolds, W.E.

    1983-09-01

    The treatment of geothermal steam by electron beam irradiation is a potential alternative method of H/sub 2/S removal which can be applied upstream or downstream and has no chemical requirements. The experimental work reported here examines the effectiveness of electron beam treatment of geothermal fluids. These fluids are produced by combining the constituents in a heated cell, which contains an electron beam transparent window. Irradiation of the contents and subsequent chemical analysis allows an evaluation of effectiveness. These results are used for a commercial feasibility assessment.

  9. Flow non-normality-induced transient growth in superposed Newtonian and non-Newtonian fluid layers.

    Science.gov (United States)

    Camporeale, C; Gatti, F; Ridolfi, L

    2009-09-01

    In recent years non-normality and transient growths have attracted much interest in fluid mechanics. Here, we investigate these topics with reference to the problem of interfacial instability in superposed Newtonian and non-Newtonian fluid layers. Under the hypothesis of the lubrication theory, we demonstrate the existence of significant transient growths in the parameter space region where the dynamical system is asymptotically stable, and show how they depend on the main physical parameters. In particular, the key role of the density ratio is highlighted.

  10. Pressure oscillation induced by composite fluid flow - Physical picture generating low frequency earthquake -

    Science.gov (United States)

    Takashima, S.; Kurita, K.

    2006-12-01

    Recently low frequency (LF) earthquakes have been found to occur in various geophysical settings. Structural inspection of the source region and analysis of focal mechanism suggest the possible role of fluid in the generation process. The nature of fluid expected in the source region should be characterized by multiphase system such as magma and gas bubble, magma and crystal and aqueous fluid and gas bubble, for example. In this system the physical properties of this composite depends on the mutual volume fraction. The volume fraction is variable depending on the flow situation. We consider the link between the flow situation and the volume fraction is an essential part of the composite flow. Here based on the concept that nature of the composite flow plays a central role in the generation of pressure oscillation, we report a simple laboratory model to demonstrate LF earthquakes. The multiphase system in the source region of the LF earthquakes is modeled here as a composite of viscous fluid and incompressible granular phase. plastic particles made of polystyrene (0.5 mm in diameter) and glycerol solution is packed into a cylindrical case (60 mm in diameter). The packing state of the solid phase is near random closed packing state. The glycerol solution flows into the case from the pressure reservoir and it goes out from exit tube with 60 mm in length and 3 mm in diameter. The pressure is measured using a pressure sensor. The control parameter is fluid pressure (1 atm plus 300 Pa to 1500 Pa) and its viscosity (30 mPas to 100 mPas) in this experiment. When the pressure difference between the case is low, the flow is characterized as a permeable flow. Only the interstitial fluid of the glycerol solution flows out depending on the pressure difference. When the pressure difference is above the critical value, both fluid and particles flow out as a composite flow. In this state the output pressure was observed to oscillate. In the diagram of power spectrum of the

  11. Synthetic modeling of a fluid injection-induced fault rupture with slip-rate dependent friction coefficient

    Science.gov (United States)

    Urpi, Luca; Rinaldi, Antonio Pio; Rutqvist, Jonny; Cappa, Frédéric; Spiers, Christopher J.

    2016-04-01

    Poro-elastic stress and effective stress reduction associated with deep underground fluid injection can potentially trigger shear rupture along pre-existing faults. We modeled an idealized CO2 injection scenario, to assess the effects on faults of the first phase of a generic CO2 aquifer storage operation. We used coupled multiphase fluid flow and geomechanical numerical modeling to evaluate the stress and pressure perturbations induced by fluid injection and the response of a nearby normal fault. Slip-rate dependent friction and inertial effects have been aken into account during rupture. Contact elements have been used to take into account the frictional behavior of the rupture plane. We investigated different scenarios of injection rate to induce rupture on the fault, employing various fault rheologies. Published laboratory data on CO2-saturated intact and crushed rock samples, representative of a potential target aquifer, sealing formation and fault gouge, have been used to define a scenario where different fault rheologies apply at different depths. Nucleation of fault rupture takes place at the bottom of the reservoir, in agreement with analytical poro-elastic stress calculations, considering injection-induced reservoir inflation and the tectonic scenario. For the stress state here considered, the first triggered rupture always produces the largest rupture length and slip magnitude, correlated with the fault rheology. Velocity weakening produces larger ruptures and generates larger magnitude seismic events. Heterogeneous faults have been considered including velocity-weakening or velocity strengthening sections inside and below the aquifer, while upper sections being velocity-neutral. Nucleation of rupture in a velocity strengthening section results in a limited rupture extension, both in terms of maximum slip and rupture length. For a heterogeneous fault with nucleation in a velocity-weakening section, the rupture may propagate into the overlying velocity

  12. Peristaltic flow of a couple stress fluid under the effect of induced magnetic field in an asymmetric channel

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, Sohail; Akram, Safia [Quaid-i-Azam University, Department of Mathematics, Islamabad (Pakistan)

    2011-01-15

    The present paper investigates the peristaltic transport of a couple stress fluid in an asymmetric channel with the effect of the induced magnetic field. The exact solutions of momentum and the magnetic field equations have been calculated under the assumptions of long wave length and low but finite Reynolds number. The expression for pressure rise has been computed numerically using mathematics software Mathematica. The graphical results have been presented to discuss the physical behavior of various physical parameters of interest. Finally, the trapping phenomena have been discussed for various physical parameters. (orig.)

  13. Changes in Stroke Volume Induced by Lung Recruitment Maneuver Predict Fluid Responsiveness in Mechanically Ventilated Patients in the Operating Room.

    Science.gov (United States)

    Biais, Matthieu; Lanchon, Romain; Sesay, Musa; Le Gall, Lisa; Pereira, Bruno; Futier, Emmanuel; Nouette-Gaulain, Karine

    2017-02-01

    Lung recruitment maneuver induces a decrease in stroke volume, which is more pronounced in hypovolemic patients. The authors hypothesized that the magnitude of stroke volume reduction through lung recruitment maneuver could predict preload responsiveness. Twenty-eight mechanically ventilated patients with low tidal volume during general anesthesia were included. Heart rate, mean arterial pressure, stroke volume, and pulse pressure variations were recorded before lung recruitment maneuver (application of continuous positive airway pressure of 30 cm H2O for 30 s), during lung recruitment maneuver when stroke volume reached its minimal value, and before and after volume expansion (250 ml saline, 0.9%, infused during 10 min). Patients were considered as responders to fluid administration if stroke volume increased greater than or equal to 10%. Sixteen patients were responders. Lung recruitment maneuver induced a significant decrease in mean arterial pressure and stroke volume in both responders and nonresponders. Changes in stroke volume induced by lung recruitment maneuver were correlated with those induced by volume expansion (r = 0.56; P recruitment maneuver predicted fluid responsiveness with a sensitivity of 88% (95% CI, 62 to 98) and a specificity of 92% (95% CI, 62 to 99). Pulse pressure variations more than 6% before lung recruitment maneuver discriminated responders with a sensitivity of 69% (95% CI, 41 to 89) and a specificity of 75% (95% CI, 42 to 95). The area under receiver operating curves generated for changes in stroke volume induced by lung recruitment maneuver (0.96; 95% CI, 0.81 to 0.99) was significantly higher than that for pulse pressure variations (0.72; 95% CI, 0.52 to 0.88; P recruitment maneuver could predict preload responsiveness in mechanically ventilated patients in the operating room.

  14. Modeling of [Formula: see text]-mediated calcium signaling in vascular endothelial cells induced by fluid shear stress and ATP.

    Science.gov (United States)

    Li, Long-Fei; Xiang, Cheng; Qin, Kai-Rong

    2015-10-01

    The calcium signaling plays a vital role in flow-dependent vascular endothelial cell (VEC) physiology. Variations in fluid shear stress and ATP concentration in blood vessels can activate dynamic responses of cytosolic-free [Formula: see text] through various calcium channels on the plasma membrane. In this paper, a novel dynamic model has been proposed for transient receptor potential vanilloid 4 [Formula: see text]-mediated intracellular calcium dynamics in VECs induced by fluid shear stress and ATP. Our model includes [Formula: see text] signaling pathways through P2Y receptors and [Formula: see text] channels (indirect mechanism) and captures the roles of the [Formula: see text] compound channels in VEC [Formula: see text] signaling in response to fluid shear stress (direct mechanism). In particular, it takes into account that the [Formula: see text] compound channels are regulated by intracellular [Formula: see text] and [Formula: see text] concentrations. The simulation studies have demonstrated that the dynamic responses of calcium concentration produced by the proposed model correlate well with the existing experimental observations. We also conclude from the simulation studies that endogenously released ATP may play an insignificant role in the process of intracellular [Formula: see text] response to shear stress.

  15. Thiazolidinone CFTR inhibitor identified by high-throughput screening blocks cholera toxin-induced intestinal fluid secretion.

    Science.gov (United States)

    Ma, Tonghui; Thiagarajah, Jay R; Yang, Hong; Sonawane, Nitin D; Folli, Chiara; Galietta, Luis J V; Verkman, A S

    2002-12-01

    Secretory diarrhea is the leading cause of infant death in developing countries and a major cause of morbidity in adults. The cystic fibrosis transmembrane conductance regulator (CFTR) protein is required for fluid secretion in the intestine and airways and, when defective, causes the lethal genetic disease cystic fibrosis. We screened 50,000 chemically diverse compounds for inhibition of cAMP/flavone-stimulated Cl(-) transport in epithelial cells expressing CFTR. Six CFTR inhibitors of the 2-thioxo-4-thiazolidinone chemical class were identified. The most potent compound discovered by screening of structural analogs, CFTR(inh)-172, reversibly inhibited CFTR short-circuit current in less than 2 minutes in a voltage-independent manner with K(I) approximately 300 nM. CFTR(inh)-172 was nontoxic at high concentrations in cell culture and mouse models. At concentrations fully inhibiting CFTR, CFTR(inh)-172 did not prevent elevation of cellular cAMP or inhibit non-CFTR Cl(-) channels, multidrug resistance protein-1 (MDR-1), ATP-sensitive K(+) channels, or a series of other transporters. A single intraperitoneal injection of CFTR(inh)-172 (250 micro g/kg) in mice reduced by more than 90% cholera toxin-induced fluid secretion in the small intestine over 6 hours. Thiazolidinone CFTR inhibitors may be useful in developing large-animal models of cystic fibrosis and in reducing intestinal fluid loss in cholera and other secretory diarrheas.

  16. Observation of depth-induced properties in wave turbulence on the surface of a fluid

    CERN Document Server

    Falcon, Eric

    2011-01-01

    We report the observation of changes in the wave turbulence properties of gravity-capillary surface waves due to a finite depth effect. When the fluid depth is decreased, a hump is observed on the wave spectrum in the capillary regime at a scale that depends on the depth. The possible origin of this hump is discussed. In the gravity regime, the wave spectrum still shows a power law but with an exponent that strongly depends on the depth. A change in the scaling of the gravity spectrum with the mean injected power is also reported. Finally, the probability density function of the wave amplitude rescaled by its rms value is found to be independent of the fluid depth and to be well described by a Tayfun distribution.

  17. Electrodynamic phenomena induced by a dark fluid: Analogs of pyromagnetic, piezoelectric, and striction effects

    CERN Document Server

    Balakin, Alexander B

    2014-01-01

    We establish a new model of coupling between a cosmic dark fluid and electrodynamic systems, based on an analogy with effects of electric and magnetic striction, piezo-electricity and piezo-magnetism, pyro-electricity and pyro-magnetism, which appear in classical electrodynamics of continuous media. Extended master equations for electromagnetic and gravitational fields are derived using Lagrange formalism. A cosmological application of the model is considered, and it is shown that a striction-type interaction between the dark energy (the main constituent of the dark fluid) and electrodynamic system provides the universe history to include the so-called unlighted epochs, during which electromagnetic waves can not propagate and thus can not scan the universe interior.

  18. Viscosity-Induced Crossing of the Phantom Divide in the Dark Cosmic Fluid

    CERN Document Server

    Brevik, Iver

    2013-01-01

    Choosing various natural forms for the equation-of-state parameter w and the bulk viscosity \\zeta, we discuss how it is possible for a dark energy fluid to slide from the quintessence region across the divide w=-1 into the phantom region, and thus into a Big Rip future singularity. Different analytic forms for \\zeta, as powers of the scalar expansion, are suggested and compared with experiments.

  19. Fluid-Induced Propulsion of Rigid Particles in Wormlike Micellar Solutions

    CERN Document Server

    Gagnon, David A; Shen, Xiaoning; Arratia, Paulo E

    2014-01-01

    In the absence of inertia, a reciprocal swimmer achieves no net motion in a viscous Newtonian fluid. Here, we investigate the ability of a reciprocally actuated particle to translate through a complex, "structured" fluid using tracking methods and birefringence imaging. A geometrically polar particle, a rod with a bead on one end, is reciprocally rotated using magnetic fields. The particle is immersed in a wormlike micellar solution that is known to be susceptible to shear banding and the formation of local anisotropic structures. Results show that the nonlinearities present in this structured fluid break time-reversal symmetry under certain conditions, and enable propulsion of an artificial "swimmer." We find three regimes dependent on the Deborah number (De): net motion towards the bead at low De, net motion towards the rod at intermediate De, and no propulsion at high De. At low De, we believe propulsion is caused by an imbalance in the first normal stress differences between the two ends of the particle (...

  20. Eye rotation induced dynamics of a Newtonian fluid within the vitreous cavity: the effect of the chamber shape

    Energy Technology Data Exchange (ETDEWEB)

    Stocchino, Alessandro [Department of Environmental Engineering, University of Genoa (Italy); Repetto, Rodolfo [Department of Engineering of Structures, Water and Soil, University of L' Aquila (Italy); Cafferata, Chiara [Department of Environmental Engineering, University of Genoa (Italy)

    2007-04-07

    The dynamics of the vitreous body induced by eye rotations is studied experimentally. In particular, we consider the case in which the vitreous cavity is filled by a Newtonian fluid, either because the vitreous is liquefied or because it has been replaced, after vitrectomy, by a viscous fluid. We employ a rigid Perspex container which models, in a magnified scale, the vitreous cavity of the human eye. The shape of the cavity closely resembles that of the real vitreous chamber; in particular, the anterior part of the container is concave in order to model the presence of the eye lens. The container is filled with glycerol and is mounted on the shaft of a computer-controlled motor which rotates according to a periodic time law. PIV (particle image velocimetry) measurements are taken on the equatorial plane orthogonal to the axis of rotation. The experimental measurements show that the velocity field is strongly influenced by the deformed geometry of the domain. In particular, the formation of a vortex in the vicinity of the lens, which migrates in time towards the core of the domain, is invariably observed. The vortex path is tracked in time by means of a vortex identification technique and it is found that it is significantly influenced by the Womersley number of the flow. Particle trajectories are computed from the PIV measurements. Particles initially located at different positions on the equatorial horizontal plane (perpendicular to the axis of rotation) tend to concentrate in narrow regions adjacent to the lens, thus suggesting the existence, in such regions, of a vertical fluid ejection. Such a strong flow three-dimensionality, which is essentially induced by the irregular shape of the domain, may play a significant role in the mixing processes taking place inside the eye globe. The tangential stresses acting on the rigid boundary of the domain are also computed from the experimental measurements showing that regions subject to particularly intense stresses

  1. Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Uvan Catton; Vijay K. Dhir; Deepanjan Mitra; Omar Alquaddoomi; Pierangelo Adinolfi

    2004-04-06

    Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers.

  2. Hyperthermia with rotating magnetic nanowires inducing heat into tumor by fluid friction

    Science.gov (United States)

    Egolf, Peter W.; Shamsudhin, Naveen; Pané, Salvador; Vuarnoz, Didier; Pokki, Juho; Pawlowski, Anne-Gabrielle; Tsague, Paulin; de Marco, Bastien; Bovy, William; Tucev, Sinisa; Ansari, M. H. D.; Nelson, Bradley J.

    2016-08-01

    A magnetic hyperthermia cancer treatment strategy that does not operate by means of conventional heating mechanisms is presented. The proposed approach consists of injecting a gel with homogeneously distributed magnetic nanowires into a tumor. Upon the application of a low-frequency rotating or circularly polarized magnetic field, nanowires spin around their center of viscous drag due to torque generated by shape anisotropy. As a result of external rotational forcing and fluid friction in the nanoparticle's boundary layer, heating occurs. The nanowire dynamics is theoretically and experimentally investigated, and different feasibility proofs of the principle by physical modeling, which adhere to medical guidelines, are presented. The magnetic nanorotors exhibit rotations and oscillations with quite a steady center of gravity, which proves an immobile behavior and guarantees a time-independent homogeneity of the spatial particle distribution in the tumor. Furthermore, a fluid dynamic and thermodynamic heating model is briefly introduced. This model is a generalization of Penne's model that for this method reveals theoretic heating rates that are sufficiently high, and fits well into medical limits defined by present standards.

  3. On the possibility of wave-induced chaos in a sheared, stably stratified fluid layer

    Directory of Open Access Journals (Sweden)

    W. B. Zimmermann

    1994-01-01

    Full Text Available Shear flow in a stable stratification provides a waveguide for internal gravity waves. In the inviscid approximation, internal gravity waves are known to be unstable below a threshold in Richardson number. However, in a viscous fluid, at low enough Reynolds number, this threshold recedes to Ri = 0. Nevertheless, even the slightest viscosity strongly damps internal gravity waves when the Richardson number is small (shear forces dominate buoyant forces. In this paper we address the dynamics that approximately govern wave propagation when the Richardson number is small and the fluid is viscous. When Ri ξ = λ1A + λ2Aξξ + λ3Aξξξ + λ4AAξ + b(ξ where ξ is the coordinate of the rest frame of the passing temperature wave whose horizontal profile is b(ξ. The parameters λi are constants that depend on the Reynolds number. The above dynamical system is know to have limit cycle and chaotic attrators when forcing is sinusoidal and wave attenuation negligible.

  4. Simulation of Fluid Flow in a Channel Induced by Three Types of Fin-Like Motion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water.Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles (AUV). In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable.In the current paper an analysis of undulatory, oscillatory and combined fim-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum are solved with the Finite Volume Method (FVM) by use of the software CFX-10.0. The undulatory and oscillatory fin movements are modelled with an equation that is implemented within an additional subroutine and joined with the main solver. Numericalsimulations are carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations are carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.

  5. Hyperthermia with rotating magnetic nanowires inducing heat into tumor by fluid friction

    Energy Technology Data Exchange (ETDEWEB)

    Egolf, Peter W.; Pawlowski, Anne-Gabrielle; Tsague, Paulin; Marco, Bastien de; Bovy, William; Tucev, Sinisa [Institute of Thermal Sciences and Engineering, University of Applied Sciences of Western Switzerland, CH 1401 Yverdon-les-Bains (Switzerland); Shamsudhin, Naveen, E-mail: snaveen@ethz.ch; Pané, Salvador; Pokki, Juho; Ansari, M. H. D.; Nelson, Bradley J. [Multi-Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, CH 8092 Zurich (Switzerland); Vuarnoz, Didier [Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL Fribourg, CH 1701 Fribourg (Switzerland)

    2016-08-14

    A magnetic hyperthermia cancer treatment strategy that does not operate by means of conventional heating mechanisms is presented. The proposed approach consists of injecting a gel with homogeneously distributed magnetic nanowires into a tumor. Upon the application of a low-frequency rotating or circularly polarized magnetic field, nanowires spin around their center of viscous drag due to torque generated by shape anisotropy. As a result of external rotational forcing and fluid friction in the nanoparticle's boundary layer, heating occurs. The nanowire dynamics is theoretically and experimentally investigated, and different feasibility proofs of the principle by physical modeling, which adhere to medical guidelines, are presented. The magnetic nanorotors exhibit rotations and oscillations with quite a steady center of gravity, which proves an immobile behavior and guarantees a time-independent homogeneity of the spatial particle distribution in the tumor. Furthermore, a fluid dynamic and thermodynamic heating model is briefly introduced. This model is a generalization of Penne's model that for this method reveals theoretic heating rates that are sufficiently high, and fits well into medical limits defined by present standards.

  6. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H.; Ramasse, Quentin M.; Hoppe, Peter; Nittler, Larry R.

    2014-01-01

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. PMID:25288736

  7. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites.

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H; Ramasse, Quentin M; Hoppe, Peter; Nittler, Larry R

    2014-10-28

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

  8. Bacterial DNA induces the complement system activation in serum and ascitic fluid from patients with advanced cirrhosis.

    Science.gov (United States)

    Francés, Rubén; González-Navajas, José M; Zapater, Pedro; Muñoz, Carlos; Caño, Rocío; Pascual, Sonia; Márquez, Dorkas; Santana, Francia; Pérez-Mateo, Miguel; Such, José

    2007-07-01

    Translocation of intestinal bacteria to ascitic fluid is, probably, the first step in the development of spontaneous bacterial peritonitis in patients with cirrhosis. Proteins of the complement system are soluble mediators implicated in the host immune response to bacterial infections and its activation has been traditionally considered to be an endotoxin-induced phenomenon. The aim of this study was to compare the modulation of these proteins in response to the presence of bacterial DNA and/or endotoxin in patients with advanced cirrhosis and ascites in different clinical conditions. Groups I and II consisted of patients without/with bacterial DNA. Group III included patients with spontaneous bacterial peritonitis and Group IV with patients receiving norfloxacin as secondary long-term prophylaxis of spontaneous bacterial peritonitis. Serum and ascitic fluid levels of endotoxin and truncated residues of the complement system were measured by ELISA. The complement system is triggered in response to bacterial DNA, as evidenced by significantly increased levels of C3b, membrane attack complex, and C5a in patients from Groups II and III compared with patients without bacterial DNA (Group I) and those receiving norfloxacin (Group IV). Gram classification did not further differentiate the immune response between patients within groups II and III, even though endotoxin levels were, as expected, significantly higher in patients with bacterial DNA from gram-negative microorganisms. The complement protein activation observed in patients with bacterial DNA in blood and ascitic fluid is indistinguishable from that observed in patients with spontaneous bacterial peritonitis and may occur in an endotoxin-independent manner.

  9. Mechanism of inhibitory actions of minocycline and doxycycline on ascitic fluid production induced by mouse fibrosarcoma cells.

    Science.gov (United States)

    Wakai, K; Ohmura, E; Satoh, T; Murakami, H; Isozaki, O; Emoto, N; Demura, H; Shizume, K; Tsushima, T

    1994-01-01

    Semisynthetic tetracyclines (TCNs) are used for the management of malignant pleural effusions as sclerosing agents. However, their precise mechanism of actions are uncertain. In the present study, the mechanism of inhibitory effects of minocycline (MINO) and doxycycline (DOXY), on the accumulation of ascitic fluid induced by mouse fibrosarcoma (Meth-A) cells were investigated using male mice. Meth-A cells inoculated intraperitoneally elicited 2.5-4 ml of bloody ascites 10 days after implantation. The production of ascitic fluid was suppressed in a dose-related manner by daily intraperitoneal injections of MINO or DOXY, whereas vehicle (normal saline with 0.01N HCl) did not exert a significant effect. The inhibitory activity of these two substances was quite similar; one mg/mouse of MINO or DOXY inhibited the accumulation of fluid by 87% and 84%, respectively. The survival rate of Meth-A-bearing mice treated with MINO or DOXY was higher than that of the controls. Macroscopic examination of the peritoneal cavity did not reveal any obvious effects, such as adhesions, in mice treated with either MINO or DOXY. In vitro studies showed that MINO and DOXY suppressed Meth-A cell growth with IC50s of 5 microM and 8 microM, respectively. Maximal suppression (95%) was achieved at MINO and DOXY concentrations of 25 microM. The above observations suggest that MINO and DOXY inhibit the accumulation of ascites by a direct effect on Meth-A cell growth. Therefore, it appears that TCNs injected into the pleural cavity to manage malignant effusions in man exert their activity, at least in part, by suppressing malignant cell growth.

  10. Many-body dipole-induced dipole model for electrorheological fluids

    Institute of Scientific and Technical Information of China (English)

    Huang Ji-Ping; Yu Kin-Wah

    2004-01-01

    Theoretical investigations on electrorheological (ER) fluids usually rely on computer simulations. An initial approach for these studies would be the point-dipole (PD) approximation, which is known to err considerably when the particles approach and finally touch each other due to many-body and multipolar interactions. Thus various works have attempted to go beyond the PD model. Being beyond the PD model, previous attempts have been restricted to either local-field effects only or multipolar effects only, but not both. For instance, we recently proposed a dipoleinduced-dipole (DID) model which is shown to be both more accurate than the PD model and easy to use. This work is necessary because the many-body (local-field) effect is included to put forth the many-body DID model. The results show that the multipolar interactions can indeed be dominant over the dipole interaction, while the local-field effect may yield a correction.

  11. Odor-induced crawling locomotion in the newborn rat: Effects of amniotic fluid and milk.

    Science.gov (United States)

    Mendez-Gallardo, Valerie; Robinson, Scott R

    2014-04-01

    Early locomotion in the neonatal rat previously has been reported 3 days after birth during exposure to an odor of biological relevance (nest material). The current study explores if other ecologically relevant stimuli-amniotic fluid (AF) and milk-could evoke a similar locomotor response in the newborn rat and whether the endogenous opioid system mediates the response. Newborn rats tested 24 hr after birth were presented with the odors of AF or milk while placed in a runway. Pups expressed crawling and moved along the runway in response to direct exposure to the odors of AF and milk (Exp. 1). However, there was no evidence that this crawling response was altered after pretreatment with the opioid antagonist naloxone (Exp. 2). This study provides evidence of the capacity of AF and milk to evoke coordinated motor behavior, suggesting that they may play a role in the development of fundamental motor patterns.

  12. Aortic dissection-induced acute flaccid paraplegia treated with cerebrospinal fluid drainage

    Directory of Open Access Journals (Sweden)

    Eduardo Leal Adam

    2012-03-01

    Full Text Available Acute aortic dissection is a life-threatening event in which prompt and correctdiagnosis is associated with better outcomes. In most cases, there is chestor back pain. However, in rare cases, patients have little or no pain andother symptoms are more conspicuous at presentation. The autors reportsthe case of a 47-year-old female patient who sought medical attention forsudden-onset paraplegia. The physical examination was normal except forbilateral lower limb flaccid paralysis, with abolition of deep tendon reflexes andparaesthesia in both feet. Computed tomography showed aortic dissection,with partial thrombosis of the false lumen, starting after the emergence of theleft subclavian artery and extending, toward the bifurcation of the aorta, to theleft iliac artery. After cerebrospinal fluid drainage, the evolution was favorable.

  13. Plate-like convection induced by symmetries in fluids with temperature-dependent viscosity

    CERN Document Server

    Curbelo, Jezabel

    2014-01-01

    The study of instabilities in fluids in which viscosity experiences a transition at a certain temperature range is of great interest for the understanding of planetary interiors, since this phenomena models the melting and solidification of a magma ocean and thus is suitable for representing a lithosphere over a convecting mantle. To this end, we study a 2D convection problem in which viscosity depends on temperature by abruptly changing its value by a factor 400 within a narrow temperature gap at which magma melts. We perform a study which combines bifurcation analysis and time dependent simulations. Solutions such as limit cycles are found that are fundamentally related to the presence of symmetry. Sporadically during these cycles, through abrupt bursts, spontaneous plate-like behaviors that rapidly evolve towards a stagnant lid regime emerge. The plate-like evolution alternates motions towards either right or left, introducing temporary asymmetries on the convecting styles. Further time dependent regimes w...

  14. Increased salt consumption induces body water conservation and decreases fluid intake.

    Science.gov (United States)

    Rakova, Natalia; Kitada, Kento; Lerchl, Kathrin; Dahlmann, Anke; Birukov, Anna; Daub, Steffen; Kopp, Christoph; Pedchenko, Tetyana; Zhang, Yahua; Beck, Luis; Johannes, Bernd; Marton, Adriana; Müller, Dominik N; Rauh, Manfred; Luft, Friedrich C; Titze, Jens

    2017-05-01

    The idea that increasing salt intake increases drinking and urine volume is widely accepted. We tested the hypothesis that an increase in salt intake of 6 g/d would change fluid balance in men living under ultra-long-term controlled conditions. Over the course of 2 separate space flight simulation studies of 105 and 205 days' duration, we exposed 10 healthy men to 3 salt intake levels (12, 9, or 6 g/d). All other nutrients were maintained constant. We studied the effect of salt-driven changes in mineralocorticoid and glucocorticoid urinary excretion on day-to-day osmolyte and water balance. A 6-g/d increase in salt intake increased urine osmolyte excretion, but reduced free-water clearance, indicating endogenous free water accrual by urine concentration. The resulting endogenous water surplus reduced fluid intake at the 12-g/d salt intake level. Across all 3 levels of salt intake, half-weekly and weekly rhythmical mineralocorticoid release promoted free water reabsorption via the renal concentration mechanism. Mineralocorticoid-coupled increases in free water reabsorption were counterbalanced by rhythmical glucocorticoid release, with excretion of endogenous osmolyte and water surplus by relative urine dilution. A 6-g/d increase in salt intake decreased the level of rhythmical mineralocorticoid release and elevated rhythmical glucocorticoid release. The projected effect of salt-driven hormone rhythm modulation corresponded well with the measured decrease in water intake and an increase in urine volume with surplus osmolyte excretion. Humans regulate osmolyte and water balance by rhythmical mineralocorticoid and glucocorticoid release, endogenous accrual of surplus body water, and precise surplus excretion. Federal Ministry for Economics and Technology/DLR; the Interdisciplinary Centre for Clinical Research; the NIH; the American Heart Association (AHA); the Renal Research Institute; and the TOYOBO Biotechnology Foundation. Food products were donated by APETITO

  15. Experimental study and finite element analysis of wind-induced vibration of modal car based on fluid-structure interaction

    Institute of Scientific and Technical Information of China (English)

    TAO Li-li; DU Guang-sheng; LIU Li-ping; LIU Yong-hui; SHAO Zhu-feng

    2013-01-01

    The wind-induced vibration of the front windshield concerns the traffic safety and the aerodynamic charactefistcs of cars.In this paper,the numerical simulation and the experiment are combined to study the wind-induced vibrations of the front windshield at different speeds of a van-body model bus.The Fluid-Structure Interaction (FSI) model is used for the finite element analysis of the vibration characteristics of the front windshield glass in the travelling process,and the wind-induced vibration response characteristics of the glass is obtained.A wind-tunnel experiment with an eddy current displacement sensor is carried out to study the deformation of the windshield at different wind speeds,and to verify the numerical simulation results.It is shown that the windshield of the model bus windshield undergoes a noticeable deformation as the speed changes,and from the deformation curve obtained,it is seen that in the accelerating process,the deformation of the glass increases as the speed increases,and with the speed being stablized,it also tends to a certain value.The results of this study can provide a scientific basis for the safety design of the windshield and the body.

  16. Seismic wave attenuation and dispersion due to wave-induced fluid flow in rocks with strong permeability fluctuations.

    Science.gov (United States)

    Germán Rubino, J; Monachesi, Leonardo B; Müller, Tobias M; Guarracino, Luis; Holliger, Klaus

    2013-12-01

    Oscillatory fluid movements in heterogeneous porous rocks induced by seismic waves cause dissipation of wave field energy. The resulting seismic signature depends not only on the rock compressibility distribution, but also on a statistically averaged permeability. This so-called equivalent seismic permeability does not, however, coincide with the respective equivalent flow permeability. While this issue has been analyzed for one-dimensional (1D) media, the corresponding two-dimensional (2D) and three-dimensional (3D) cases remain unexplored. In this work, this topic is analyzed for 2D random medium realizations having strong permeability fluctuations. With this objective, oscillatory compressibility simulations based on the quasi-static poroelasticity equations are performed. Numerical analysis shows that strong permeability fluctuations diminish the magnitude of attenuation and velocity dispersion due to fluid flow, while the frequency range where these effects are significant gets broader. By comparing the acoustic responses obtained using different permeability averages, it is also shown that at very low frequencies the equivalent seismic permeability is similar to the equivalent flow permeability, while for very high frequencies this parameter approaches the arithmetic average of the permeability field. These seemingly generic findings have potentially important implications with regard to the estimation of equivalent flow permeability from seismic data.

  17. Fluid modeling of resistive plate chambers: impact of transport data on development of streamers and induced signals

    Science.gov (United States)

    Bošnjaković, D.; Petrović, Z. Lj; Dujko, S.

    2016-10-01

    We discuss the implementation of transport data in modeling of resistive plate chambers (RPCs), which are used for timing and triggering purposes in many high energy physics experiments. Particularly, we stress the importance of making a distinction between flux and bulk transport data when non-conservative collisions, such as attachment and/or ionization, are present. A 1.5-dimensional fluid model with photoionization is employed to demonstrate how the duality of transport data affects the calculated signals of the ATLAS triggering RPC and ALICE timing RPC used at CERN, and also a timing RPC with high \\text{S}{{\\text{F}}6} content. It is shown that in the case of timing RPCs, the difference between the induced charges calculated using flux and bulk transport data can reach several hundred percent at lower operating electric fields. The effects of photoionization and space charge are also discussed.

  18. Roughness-induced fluid interface fluctuations due to polar and apolar interactions

    NARCIS (Netherlands)

    Palasantzas, G; Backx, G

    1999-01-01

    We investigate substrate roughness-induced fluctuations on liquid films in the presence of polar (exponential) and apolar (van der Waals) interactions in the complete wetting regime. The liquid/vapor interface roughness amplitude sigma(w) increases rapidly with film thickness epsilon above a critica

  19. Preemptive hemodynamic intervention restricting the administration of fluids attenuates lung edema progression in oleic acid-induced lung injury.

    Science.gov (United States)

    Gil Cano, A; Gracia Romero, M; Monge García, M I; Guijo González, P; Ruiz Campos, J

    2017-04-01

    A study is made of the influence of preemptive hemodynamic intervention restricting fluid administration upon the development of oleic acid-induced lung injury. A randomized in vivo study in rabbits was carried out. University research laboratory. Sixteen anesthetized, mechanically ventilated rabbits. Hemodynamic measurements obtained by transesophageal Doppler signal. Respiratory mechanics computed by a least square fitting method. Lung edema assessed by the ratio of wet weight to dry weight of the right lung. Histological examination of the left lung. Animals were randomly assigned to either the early protective lung strategy (EPLS) (n=8) or the early protective hemodynamic strategy (EPHS) (n=8). In both groups, lung injury was induced by the intravenous infusion of oleic acid (OA) (0.133mlkg(-1)h(-1) for 2h). At the same time, the EPLS group received 15mlkg(-1)h(-1) of Ringer lactate solution, while the EPHS group received 30mlkg(-1)h(-1). Measurements were obtained at baseline and 1 and 2h after starting OA infusion. After 2h, the cardiac index decreased in the EPLS group (p<0.05), whereas in the EPHS group it remained unchanged. Lung compliance decreased significantly only in the EPHS group (p<0.05). Lung edema was greater in the EPHS group (p<0.05). Histological damage proved similar in both groups (p=0.4). In this experimental model of early lung injury, lung edema progression was attenuated by preemptively restricting the administration of fluids. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  20. An energy-based approach to estimate seismic attenuation due to wave-induced fluid flow in heterogeneous poroelastic media

    Science.gov (United States)

    Solazzi, Santiago G.; Rubino, J. Germán; Müller, Tobias M.; Milani, Marco; Guarracino, Luis; Holliger, Klaus

    2016-11-01

    Wave-induced fluid flow (WIFF) due to the presence of mesoscopic heterogeneities is considered as one of the main seismic attenuation mechanisms in the shallower parts of the Earth's crust. For this reason, several models have been developed to quantify seismic attenuation in the presence of heterogeneities of varying complexity, ranging from periodically layered media to rocks containing fractures and highly irregular distributions of fluid patches. Most of these models are based on Biot's theory of poroelasticity and make use of the assumption that the upscaled counterpart of a heterogeneous poroelastic medium can be represented by a homogeneous viscoelastic solid. Under this dynamic-equivalent viscoelastic medium (DEVM) assumption, attenuation is quantified in terms of the ratio of the imaginary and real parts of a frequency-dependent, complex-valued viscoelastic modulus. Laboratory measurements on fluid-saturated rock samples also rely on this DEVM assumption when inferring attenuation from the phase shift between the applied stress and the resulting strain. However, whether it is correct to use an effective viscoelastic medium to represent the attenuation arising from WIFF at mesoscopic scales in heterogeneous poroelastic media remains largely unexplored. In this work, we present an alternative approach to estimate seismic attenuation due to WIFF. It is fully rooted in the framework of poroelasticity and is based on the quantification of the dissipated power and stored strain energy resulting from numerical oscillatory relaxation tests. We employ this methodology to compare different definitions of the inverse quality factor for a set of pertinent scenarios, including patchy saturation and fractured rocks. This numerical analysis allows us to verify the correctness of the DEVM assumption in the presence of different kinds of heterogeneities. The proposed methodology has the key advantage of providing the local contributions of energy dissipation to the overall

  1. Protein profile of Beta vulgaris leaf apoplastic fluid and changes induced by Fe deficiency and Fe resupply

    Directory of Open Access Journals (Sweden)

    Laura eCeballos-Laita

    2015-03-01

    Full Text Available The fluid collected by direct leaf centrifugation has been used to study the proteome of the sugar beet apoplastic fluid as well as the changes induced by Fe deficiency and Fe resupply to Fe-deficient plants in the protein profile. Plants were grown in Fe-sufficient and Fe-deficient conditions, and Fe resupply was carried out with 45 μM Fe(III-EDTA for 24 h. Protein extracts of leaf apoplastic fluid were analyzed by two-dimensional isoelectric focusing-SDS-PAGE electrophoresis. Gel image analysis revealed 203 consistent spots, and proteins in 81% of them (164 were identified by nLC-MS/MS using a custom made reference repository of beet protein sequences. When redundant UniProt entries were deleted, a non-redundant leaf apoplastic proteome consisting of 109 proteins was obtained. TargetP and SecretomeP algorithms predicted that 63% of them were secretory proteins. Functional classification of the non-redundant proteins indicated that stress and defense, protein metabolism, cell wall and C metabolism accounted for approximately 75% of the identified proteome. The effects of Fe-deficiency on the leaf apoplast proteome were limited, with only five spots (2.5% changing in relative abundance, thus suggesting that protein homeostasis in the leaf apoplast fluid is well maintained upon Fe shortage. The identification of three chitinase isoforms among proteins increasing in relative abundance with Fe-deficiency suggests that one of the few effects of Fe deficiency in the leaf apoplast proteome includes cell wall modifications. Iron resupply to Fe deficient plants changed the relative abundance of 16 spots when compared to either Fe-sufficient or Fe-deficient samples. Proteins identified in these spots can be broadly classified as those responding to Fe-resupply, which included defense and cell wall related proteins, and non-responsive, which are mainly protein metabolism related proteins and whose changes in relative abundance followed the same trend as

  2. Crystallo-optic diagnostics method of the soft laser-induced effects in biological fluids

    Science.gov (United States)

    Skopinov, S. A.; Yakovleva, S. V.

    1991-05-01

    Presently, it is well known that individual cells"2 and higher organisms3'4 exhibit a marked response to soft laser irradiation in certain parts of the visible and near infrared spectral ranges. Broad clinical applications of laser therapy and slow progress in understanding of the physical, chemical and biological mechanisms of this phenomenon make the task to search new methods of objectivisation of laser-induces bioeffects very insistent. In this paper we give a short review of the methods of structural-optical diagnostics of the soft laser-induced effects in biofluids (blood and its fractions, saliva, juices, mucuses, exudations, etc.) and suggest their applications in experimental and clinical studies of the soft laser bioeffects.

  3. The effect of magnetic field induced aggregates on ultrasound propagation in aqueous magnetic fluid

    Science.gov (United States)

    Parekh, Kinnari; Upadhyay, R. V.

    2017-06-01

    Ultrasonic wave propagation in the aqueous magnetic fluid is investigated for different particle concentrations. The sound velocity decreases while acoustic impedance increases with increasing concentrations. The velocity anisotropy is observed upon application of magnetic field. The velocity anisotropy fits with Tarapov's theory suggests the presence of aggregates in the system. We report that these aggregates are thermodynamically unstable and the length of aggregate changes continuously with increasing concentration and, or magnetic field and resulted in a decrease in effective magnetic moment. The Taketomi's theory fits well with the experimental data suggesting that the particle clusters are aligned in the direction of the magnetic field. The radius of cluster found to increase with increasing concentration, and then decreases whereas the elastic force constant increases and then becomes constant. The increase in cluster radius indicates elongation of aggregate length due to tip-to-tip interaction of aggregates whereas for higher concentration, the lateral alignment is more favorable than tip-to-tip alignment of aggregates which reduces the cluster radius making elastic force constant to raise. Optical images show that the chains are fluctuating and confirming the lateral alignment of chains at higher fields.

  4. Investigating the fluid mechanics behind red blood cell-induced lateral platelet motion

    Science.gov (United States)

    Crowl Erickson, Lindsay; Fogelson, Aaron

    2009-11-01

    Platelets play an essential role in blood clotting; they adhere to damaged tissue and release chemicals that activate other platelets. Yet in order to adhere, platelets must first come into contact with the injured vessel wall. Under arterial flow conditions, platelets have an enhanced concentration near blood vessel walls. This non-uniform cell distribution depends on the fluid dynamics of blood as a heterogeneous medium. We use a parallelized lattice Boltzmann-immersed boundary method to solve the flow dynamics of red cells and platelets in a periodic 2D vessel with no-slip boundary conditions. Red cells are treated as biconcave immersed boundary objects with isotropic Skalak membrane tension and an internal viscosity five times that of the surrounding plasma. Using this method we analyze the influence of shear rate, hematocrit, and red cell membrane properties on lateral platelet motion. We find that the effective diffusion of platelets is significantly lower near the vessel wall compared to the center of the vessel. Insight gained from this work could lead to significant improvements to current models for platelet adhesion where the presence of red blood cells is neglected due to computational intensity.

  5. Effect of benfotiamine in podocyte damage induced by peritoneal dialysis fluid

    Directory of Open Access Journals (Sweden)

    Sandra eMüller-Krebs

    2015-03-01

    Full Text Available Background:In peritoneal dialysis (PD residual renal function (RRF fundamentally contributes to improved quality of life and patient survival. High glucose and advanced glycation end-products (AGE contribute locally to peritoneal and systemically to renal damage. Integrity of podocyte structure and function is of special importance to preserve RRF. Benfotiamine could counteract the glucose and AGE mediated toxicity by blocking hyperglycemia associated podocyte damage via the pentose phosphate pathway.Methods: A human differentiated podocyte cell line was incubated with control solution (Control, 2.5% glucose solution (Glucose and 2.5% PD fluid (PDF for 48 h either ± 50 μM benfotiamine.Podocyte damage and potential benefit of benfotiamine were analyzed using immunofluorescence, western blot analysis, and a functional migration assay. For quantitation, a semiquantitative score was used. Results:When incubating podocytes with benfotiamine, Glucose and PDF mediated damage was reduced resulting in lower expression of AGE and intact podocin and ZO-1 localization. The reorganization of the actin cytoskeleton was restored in the presence of benfotiamine as functional podocyte motility reached Control level. Decreased level of inflammation could be shown as well as reduced podocyte apoptosis.Conclusions:These data suggest that benfotiamine protects podocytes from Glucose and PDF mediated dysfunction and damage, in particular with regard to cytoskeletal reorganization, motility, inflammation and podocyte survival.

  6. A Fluid Helmet Liner for Protection Against Blast Induced Traumatic Brain Injury

    Science.gov (United States)

    2010-05-01

    Induced Traumatic Brain Injury 5a. CONTRACT NUMBER 5b. GRANT NUMBER N00014-08-1-0261 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Young, Laurence , R... Laurence R. Young Steven F. Son George A. Christou Matthew D. Alley Rahul Goel Andrew P. Vechart Benjamin R. Schimizze Table of Contents...Beach, South Carolina, Battelle Press, Columbus, pp. 29-38,1997. 10. Grover ,R., Ree , F. A., and Holmes, N., "Equation of state from Si02 Aerogel

  7. Detection and optical imaging of induced convection under the action of static gradient magnetic field in a non-conducting diamagnetic fluid

    CERN Document Server

    Morarka, Amit R

    2016-01-01

    The report elaborates experimental observations of magnetically induced convection in a non- conducting diamagnetic fluid. Suspension of Deionized (DI) water and Lycopodium pollen grains was used as the fluid in a test tube. Permanent magnets having field strength of 0.12T each were used to provide the static gradient magnetic field. The convections were visually observed and recorded using travelling microscope attached with a web camera. Various geometrical configurations of magnets in the vicinity of test tube were used which provided different types of orientation of convective flows in the test tube. Convections were observed over a range of fluid volumes from 0.2ml-10ml. The experimentally observed results provide proof of concept that irrespective of the weak interactions of diamagnetic fluids with magnetic fields, these effects can be easily observed and recorded with the use of low tech laboratory equipments.

  8. Enhanced generation of retinal progenitor cells from human retinal pigment epithelial cells induced by amniotic fluid

    Directory of Open Access Journals (Sweden)

    Sanie-Jahromi Fatemeh

    2012-04-01

    Full Text Available Abstract Background Retinal progenitor cells are a convenient source of cell replacement therapy in retinal degenerative disorders. The purpose of this study was to evaluate the expression patterns of the homeobox genes PAX6 and CHX10 (retinal progenitor markers during treatment of human retinal pigment epithelium (RPE cells with amniotic fluid (AF, RPE cells harvested from neonatal cadaver globes were cultured in a mixture of DMEM and Ham's F12 supplemented with 10% FBS. At different passages, cells were trypsinized and co-cultured with 30% AF obtained from normal fetuses of 1416 weeks gestational age. Results Compared to FBS-treated controls, AF-treated cultures exhibited special morphological changes in culture, including appearance of spheroid colonies, improved initial cell adhesion and ordered cell alignment. Cell proliferation assays indicated a remarkable increase in the proliferation rate of RPE cells cultivated in 30% AF-supplemented medium, compared with those grown in the absence of AF. Immunocytochemical analyses exhibited nuclear localization of retinal progenitor markers at a ratio of 33% and 27% for CHX10 and PAX6, respectively. This indicated a 3-fold increase in retinal progenitor markers in AF-treated cultures compared to FBS-treated controls. Real-time PCR data of retinal progenitor genes (PAX6, CHX10 and VSX-1 confirmed these results and demonstrated AF's capacity for promoting retinal progenitor cell generation. Conclusion Taken together, the results suggest that AF significantly promotes the rate of retinal progenitor cell generation, indicating that AF can be used as an enriched supplement for serum-free media used for the in vitro propagation of human progenitor cells.

  9. Flow-induced agitations create a granular fluid: Effective viscosity and fluctuations

    Science.gov (United States)

    Nichol, Kiri; van Hecke, Martin

    2012-06-01

    We fluidize a granular medium with localized stirring in a split-bottom shear cell. We probe the mechanical response of quiescent regions far from the main flow by observing the vertical motion of cylindrical probes rising, sinking, and floating in the grains. First, we find that the probe motion suggests that the granular material behaves in a liquid-like manner: high-density probes sink and low-density probes float at the depth given by Archimedes’ law. Second, we observe that the drag force on moving probes scales linearly with their velocity, which allows us to define an effective viscosity for the system. This effective viscosity is inversely proportional to the rotation rate of the disk which drives the split bottom flow. Moreover, the apparent viscosity depends on radius and mass of the probe: despite the linear dependence of the drag forces on sinking speed of the probe, the granular medium is not simply Newtonian, but exhibits a more complex rheology. The decrease of viscosity with filling height of the cell, combined with the poor correlation between local strain rate and viscosity, suggests that the fluid-like character of the material is set by agitations generated in the stirred region: the relation between applied stress and observed strain rate in one location depends on the strain rate in another location. We probe the nature of the granular fluctuations that we believe mediates these nonlocal interactions by characterizing the small and random up and down motion that the probe experiences. These Gaussian fluctuations exhibit a mix of diffusive and subdiffusive behavior at short times and saturate at a value of roughly 1/10th of a grain diameter longer times, consistent with the picture of a random walker in a potential well. The product of crossover time and effective viscosity is constant, evidencing a direct link between fluctuations and viscosity.

  10. Lateral fluid percussion injury of the brain induces CCL20 inflammatory chemokine expression in rats

    Directory of Open Access Journals (Sweden)

    Das Mahasweta

    2011-10-01

    Full Text Available Abstract Background Traumatic brain injury (TBI evokes a systemic immune response including leukocyte migration into the brain and release of pro-inflammatory cytokines; however, the mechanisms underlying TBI pathogenesis and protection are poorly understood. Due to the high incidence of head trauma in the sports field, battlefield and automobile accidents identification of the molecular signals involved in TBI progression is critical for the development of novel therapeutics. Methods In this report, we used a rat lateral fluid percussion impact (LFPI model of TBI to characterize neurodegeneration, apoptosis and alterations in pro-inflammatory mediators at two time points within the secondary injury phase. Brain histopathology was evaluated by fluoro-jade (FJ staining and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL assay, polymerase chain reaction (qRT PCR, enzyme linked immunosorbent assay (ELISA and immunohistochemistry were employed to evaluate the CCL20 gene expression in different tissues. Results Histological analysis of neurodegeneration by FJ staining showed mild injury in the cerebral cortex, hippocampus and thalamus. TUNEL staining confirmed the presence of apoptotic cells and CD11b+ microglia indicated initiation of an inflammatory reaction leading to secondary damage in these areas. Analysis of spleen mRNA by PCR microarray of an inflammation panel led to the identification of CCL20 as an important pro-inflammatory signal upregulated 24 h after TBI. Although, CCL20 expression was observed in spleen and thymus after 24h of TBI, it was not expressed in degenerating cortex or hippocampal neurons until 48 h after insult. Splenectomy partially but significantly decreased the CCL20 expression in brain tissues. Conclusion These results demonstrate that the systemic inflammatory reaction to TBI starts earlier than the local brain response and suggest that spleen- and/ or thymus-derived CCL20 might play a role in

  11. Weyl spin-orbit-coupling-induced interactions in uniform and trapped atomic quantum fluids

    Science.gov (United States)

    Gupta, Reena; Singh, G. S.; Bosse, Jürgen

    2013-11-01

    We establish through analytical and numerical studies of thermodynamic quantities for noninteracting atomic gases that the isotropic three-dimensional spin-orbit coupling, the Weyl coupling, induces interaction which counters “effective” attraction (repulsion) of the exchange symmetry present in zero-coupling Bose (Fermi) gas. The exact analytical expressions for the grand potential and hence for several thermodynamic quantities have been obtained for this purpose in both uniform and trapped cases. It is enunciated that many interesting features of spin-orbit-coupled systems revealed theoretically can be understood in terms of coupling-induced modifications in statistical interparticle potential. The temperature dependence of the chemical potential, specific heat, and isothermal compressibility for a uniform Bose gas is found to have signature of the incipient Bose-Einstein condensation in the very weak coupling regime although the system does not really go in the Bose-condensed phase. The transition temperature in the harmonically trapped case decreases with an increase of coupling strength consistent with the weakening of the statistical attractive interaction. Anomalous behavior of some thermodynamic quantities, partly akin to that in dimensions less than two, appears for uniform fermions as soon as the Fermi level goes down the Dirac point on increasing the coupling strength. It is suggested that the fluctuation-dissipation theorem can be utilized to verify anomalous behaviors from studies of long-wavelength fluctuations in bunching and antibunching effects.

  12. D-foam-induced flavor condensates and breaking of supersymmetry in free Wess-Zumino fluids

    CERN Document Server

    Mavromatos, N E; Tarantino, W

    2011-01-01

    Recently {[}N. E. Mavromatos and S. Sarkar, New J. Phys. 10, 073009 (2008); N. E. Mavromatos, S. Sarkar, and W. Tarantino, Phys. Rev. D 80, 084046 (2009)], we argued that a particular model of string-inspired quantum space-time foam (D-foam) may induce oscillations and mixing among flavored particles. As a result, rather than the mass-eigenstate vacuum, the correct ground state to describe the underlying dynamics is the flavor vacuum, proposed some time ago by Blasone and Vitiello as a description of quantum field theories with mixing. At the microscopic level, the breaking of target-space supersymmetry is induced in our space-time foam model by the relative transverse motion of brane defects. Motivated by these results, we show that the flavor vacuum, introduced through an inequivalent representation of the canonical (anti-) commutation relations, provides a vehicle for the breaking of supersymmetry at a low-energy effective field-theory level; on considering the flavor-vacuum expectation value of the energy...

  13. A finite element perturbation method for computing fluid-induced forces on a certrifugal impeller rotating and whirling in a volute casing

    NARCIS (Netherlands)

    Jonker, Jan B.; van Essen, T.G.; van Essen, T.G.

    1997-01-01

    A finite element based method has been developed for computing time-averaged fluid-induced radial excitation forces and rotor dynamic forces on a two-dimensional centrifugal impeller rotating and whirling in a volute casing. In this method potential flow theory is used, which implies the assumption

  14. A finite element perturbation method for computing fluid-induced forces on a centrifugal impeller rotating and whirling in a volute casing

    NARCIS (Netherlands)

    Jonker, J.B.; Essen, van T.G.

    1997-01-01

    A finite element based method has been developed for computing time-averaged fluid-induced radial excitation forces and rotor dynamic forces on a two-dimensional centrifugal impeller rotating and whirling in a volute casing. In this method potential flow theory is used, which implies the assumption

  15. Expression of inducible nitric oxide synthase and effects of L-arginine on colonic nitric oxide production and fluid transport in patients with "minimal colitis"

    DEFF Research Database (Denmark)

    Perner, Anders; Andresen, Lars; Normark, Michel;

    2005-01-01

    Some patients with idiopathic, chronic diarrhoea have minimal, non-specific colonic inflammation. As nitric oxide (NO) acts as a secretagogue in the colon, we studied the expression of inducible NO synthase (iNOS) in mucosal biopsies and the effects of NOS stimulation on colonic transfer of fluid...

  16. Numerical analysis of wave-induced fluid flow effects related to mesoscopic heterogeneities for realistic models of porous media

    Science.gov (United States)

    Rubino, J. G.; Holliger, K.

    2010-12-01

    The classical version of the theory of poro-elasticity assumes that wave-induced fluid movements at the macroscopic scale, as defined by the prevailing wavelengths, are the only causes of seismic velocity dispersion and attenuation in porous media. Correspondingly, the probed material is implicitly supposed to be homogeneous at the microscopic and mesoscopic scales and all poro-elastic moduli are real-valued and independent of frequency. By now, there is, however, consistent evidence to demonstrate that, on their own, the physical mechanisms of classical poro-elasticity are unable to account for the attenuation behavior inferred from seismic observations. There is also increasing evidence indicating that structural and/or compositional heterogeneity at the mesoscopic scale is likely to be capable of explaining much of the excess attenuation observed in real data. Numerical modeling of poro-elastic seismic wave propagation in general and in the presence of mesoscopic heterogeneities in particular is inherently difficult. For this reason, most available work on this topic considers simplified geometries, such as periodically layered, binary distribution of the physical properties of the rock frame and/or the saturating pore fluids or mixtures of two porous phases characterized by a single dominant length scale. While such models have greatly contributed to a better conceptual understanding and quantification of the observed attenuation of seismic waves in porous media, they are often inadequate to account for specific geological and/or petrophysical details of a given situation. A primary reason for this is that to a first approximation many, if not most, typical porous rocks are characterized by continuous, scale-invariant distributions of the hydraulic and elastic material parameters as well as by continuously varying saturation levels. Mesoscopic heterogeneity of this type is not amenable to direct numerical modeling and we therefore address this problem through a

  17. Fluid-induced martitization of magnetite in BIFs from the Dharwar Craton, India.

    Science.gov (United States)

    Wagner, Christiane; Orberger, Beate; Tudryn, Alina; Wirth, Richard; Morgan, Rachael

    2013-04-01

    Banded iron formations (BIFs) represent the largest iron deposits on Earth, which mainly formed in the Late Archean and Early Proterozoic. The complex geological history of BIFs makes it difficult to reconstruct the primary mineralogy and thus the initial depositional environment. Magnetite and hematite are the most important iron oxide minerals in BIFs. Magnetite (FeOFe2O3) comprising of both ferrous and ferric iron, easily undergoes transformation at low temperature. Hematite (α-Fe2O3) is often a result of the pseudomorphic replacement of magnetite, in the processus called martitisation. Despite the process of martitization having been widely studied, in both synthetic and natural magnetites, the mechanics of the transformation are poorly understood. What is generally agreed is that the transformation from magnetite to hematite occurs via a maghemite (g-Fe2O3) intermediate. The 2.9 Ga BIF from the Western Dharwar Craton, Southern India (a 500 m thick Archean BIF), is characterized by millimetric to centrimetric alternating white quartz and grey Fe-oxide bands. The Fe-oxide bands consist of martite crystals (~20µm) which represent the hematitisation of euhedral magnetite. The hematite crystals are in part euhedral, cubic shaped pointing to the replacement of magnetite. The crystals show a trellis pattern. Magnetite patches occur within the hematite. Raman spectroscopy, X-Ray diffraction, Curie balance and magnetic hysteresis analyses and FIB-TEM investigation indicate the presence of maghemite, and the presence of subhedral magnetite and interstitial hematite crystal. The latter are characterized by dislocation with fluid inclusions and high porosity zones. The magnetite grains contain lamellae and the interfaces between magnetite-maghemite and hematite are curved suggesting grain boundary migrations with the growth of hematite at the expense of magnetite and maghemite. It is thus suggested that martite result from low-T exsolutions along cleavage resulting in

  18. A presedation fluid bolus does not decrease the incidence of propofol-induced hypotension in pediatric patients.

    Science.gov (United States)

    Jager, Matthew D; Aldag, Jean C; Deshpande, Girish G

    2015-02-01

    Propofol is commonly used in pediatric sedation, which may cause hypotension during induction. Our goal was to determine the effect of a preinduction 20-mL/kg isotonic fluid bolus on propofol-induced hypotension, assess clinical signs of hypoperfusion during hypotension, and evaluate for age-related propofol dosing differences. This prospective, randomized, controlled, nonblinded study was conducted at Children's Hospital of Illinois. Patients were children 6 to 60 months of age who needed sedation for MRI or auditory brainstem-evoked response testing. The treatment group received a preinduction 20-mL/kg isotonic saline bolus before procedure initiation. Patients were continuously monitored via cardiorespiratory monitor with pulse oximetry and end-tidal carbon dioxide measurements. Cardiovascular indices and clinical signs of hypoperfusion were compared between groups, and propofol dosing differences were compared between age groups. One hundred twenty-six patients were randomly assigned to treatment (n=52) or control (n=74) conditions. Twelve patients in the treatment group and 14 patients in the control group experienced postinduction hypotension, as defined by the Pediatric Advanced Life Support guidelines. One patient in each group was given volume resuscitation when blood pressure did not improve after a reduction in the propofol infusion rate. No hypotensive patients had physical signs of hypoperfusion, and patients≤1 year of age needed significantly more propofol. A 20-mL/kg preinduction isotonic saline bolus does not prevent propofol-induced hypotension. No clinical signs of hypoperfusion were noted with induced hypotension, and infants≤12 months old need significantly more propofol per kilogram for procedures. Copyright © 2015 by the American Academy of Pediatrics.

  19. The dependence of induced polarization on fluid salinity and pH, studied with an extended model of membrane polarization

    Science.gov (United States)

    Hördt, Andreas; Bairlein, Katharina; Bielefeld, Anja; Bücker, Matthias; Kuhn, Eva; Nordsiek, Sven; Stebner, Hermann

    2016-12-01

    The estimation of hydraulic parameters from spectral induced polarization (SIP) measurements is difficult partly because the electrical impedance of sediments depends on several parameters that are not related to the texture. Important parameters that influence the spectral response are fluid salinity and pH. In order to understand the behaviour of SIP spectra from a mechanistic point of view, we carry out simulations with a membrane polarization model. The geometry consists of a sequence of wide and narrow pores with finite radii. The charge distribution at the mineral surface is described by a triple layer model, characterized by the zeta potential and the partition coefficient. We extended an existing model by incorporating known dependencies of the zeta potential and the partition coefficient on fluid salinity and pH. Our simulation results predict a decrease of the maximum phase shift of the complex electrical conductivity with increasing salinity, consistent with experimental observations. For very small pore radii, the phase shift may also show the opposite behaviour and increase with salinity. The imaginary conductivity at 1 Hz increases with increasing salinity, followed by a peak and a decrease at high salinities. The fact that our model predicts a decrease of the imaginary conductivity at high salinities is particularly important, because strong experimental evidence was recently found for such a decrease, which was theoretically unexplained so far. Both the maximum phase shift and the imaginary conductivity at 1 Hz decrease when pH decreases. The reason is that at low pH, the zeta potential and the partition coefficient both decrease, corresponding to a smaller charge density at the mineral surface, resulting in a weaker impact of the electrical double layer. The few existing experimental studies on pH dependence are qualitatively consistent with our simulation results.

  20. Molecular Nanoshearing: An Innovative Approach to Shear off Molecules with AC-Induced Nanoscopic Fluid Flow

    Science.gov (United States)

    Shiddiky, Muhammad J. A.; Vaidyanathan, Ramanathan; Rauf, Sakandar; Tay, Zhikai; Trau, Matt

    2014-01-01

    Early diagnosis of disease requires highly specific measurement of molecular biomarkers from femto to pico-molar concentrations in complex biological (e.g., serum, blood, etc.) samples to provide clinically useful information. While reaching this detection limit is challenging in itself, these samples contain numerous other non-target molecules, most of which have a tendency to adhere to solid surfaces via nonspecific interactions. Herein, we present an entirely new methodology to physically displace nonspecifically bound molecules from solid surfaces by utilizing a newly discovered ``tuneable force'', induced by an applied alternating electric field, which occurs within few nanometers of an electrode surface. This methodology thus offers a unique ability to shear-off loosely bound molecules from the solid/liquid interface. Via this approach, we achieved a 5-fold reduction in nonspecific adsorption of non-target protein molecules and a 1000-fold enhancement for the specific capture of HER2 protein in human serum.

  1. Acute coagulopathy of trauma: balancing progressive catecholamine induced endothelial activation and damage by fluid phase anticoagulation

    DEFF Research Database (Denmark)

    Johansson, P I; Ostrowski, S R

    2010-01-01

    .e., the circulating blood and the vascular endothelium. There appears to be a dose-dependency with regards to injury severity and the hemostatic response to trauma evaluated in whole blood by viscoelastic assays like thrombelastography (TEG), changing from normal to hypercoagulable, to hypocoagulable and finally......Acute coagulopathy of trauma predicts a poor clinical outcome. Tissue trauma activates the sympathoadrenal system resulting in high circulating levels of catecholamines that influence hemostasis dose-dependently through immediate effects on the two major compartments of hemostasis, i......, is an evolutionary developed response that counterbalances the injury and catecholamine induced endothelial activation and damage. Given this, the rise in circulating catecholamines in trauma patients may favor a switch from hyper- to hypocoagulability in the blood to keep the progressively more procoagulant...

  2. Accounting for the effects of pore fluid chemistry on spectral induced polarization (SIP) measurements: the specific polarizability concept

    Science.gov (United States)

    Slater, L. D.; Weller, A.; Zhang, C.; Breede, K.; Johnson, T. J.; Nordsiek, S.; Redden, G. D.; Fox, D. T.

    2011-12-01

    Recent spectral induced polarization (SIP) research has advanced our understanding of the controls of the physical and hydraulic properties of porous media on both the polarization magnitude and relaxation length scales in porous media. A critical current challenge is to improve our understanding of how pore fluid chemistry modifies the interfacial polarization measured with the SIP technique. We report results from two laboratory-scale experiments designed to advance this understanding. In the first experiment, we analyzed the influence of electrolyte concentration and valence on the interfacial polarization of three sandstones with differing porosity and permeability. A Debye decomposition (DD) approach was used to determine normalized chargeability and average relaxation time from spectral data. We find that SIP measurements of the polarization magnitude (single frequency imaginary conductivity and normalized chargeability derived from the DD) of sandstone samples can be described by the product of the pore space related internal surface and a quantity that represents the polarizability of the mineral-fluid interface and depends on electrolyte concentration and valence. We introduce a new parameter, the specific polarizability, describing this dependence. In the second experiment, we investigated the effect of pH and hydroxyl ion concentration on the interfacial polarization of both silica gel and well-sorted sand. We find a strong dependence of the polarization on pH in the silica gel. Evidence for the same dependence exists for the sand, although the signal is only just above the noise threshold (~0.1 mrad) of the instrument. We relate the weaker signal observed in the sands to the much smaller pore space related internal surface relative to silica gel, a unique substance with surface area in excess of 500 m2/g. These observations suggest that the specific polarizability is also a function of pH, although the pH dependence is likely to be weak in SIP

  3. Fluid Shifts

    Science.gov (United States)

    Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.; Liu, J.; Macias, B.; Martin, D. S.; Minkoff, L.; Ploutz-Snyder, R.; Ribeiro, L. C.; Sargsyan, A.; Smith, S. M.

    2017-01-01

    Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid

  4. Numerical modeling of the source mechanism for microseismic events induced during fluid injection

    Science.gov (United States)

    Zhao, X.; Reyes-Montes, J.; Young, R.

    2013-12-01

    Passive microseismic (MS) monitoring is now common practice for imaging and real-time feedback of geological reservoir stimulation operations in a number of energy sectors. MS locations provide first-hand information of the fracture network geometry and propagation; however a full understanding of the fundamental processes of induced fracturing requires the use of additional information contained in the recorded waveforms. One of the current challenges is robustly solving the focal mechanism of recorded MS events from a sparse array, such as single borehole linear arrays. In this study, a synthetic rock mass model (SRM), a distinct element method, was developed to model typical source fracturing modes associated with reservoir stimulation, including shear dislocation (strike-slip and dip-slip), dilation (tensile), and explosion. The body forces directly exerted by source particles were monitored using linear sets of particle arrays simulating the sensors in field operations. The disturbance at each receiver (particle in the model) was recorded in three orthogonal directions to get 3-component waveforms. The model was validated analysing source mechanisms using a moment tensor inversion of P-wave time-domain amplitudes. The fault plane solution was also calculated from the distribution of P-wave first-break polarities. The moment tensor was then decomposed into eigenvalues and eigenvectors representing the principal axes (pressure, null and tension) of the source. Percentage isotropic, double-couple and compensated linear vector dipole components were calculated, along with orientations of the fault plane solution. The inverted moment and fault plane solutions show the similar failure modes to the source motion applied to the fault plane. This shows that the modelling approach can be used to combine different basic source modes to build a database that provides a tool to directly compare modelled and field data in order to probabilistically estimate a feasible focal

  5. Effects of tylosin, tilmicosin and tulathromycin on inflammatory mediators in bronchoalveolar lavage fluid of lipopolysaccharide-induced lung injury.

    Science.gov (United States)

    Er, Ayse; Yazar, Enver

    2012-12-01

    The aim of this study was to determine the anti-inflammatory effects of macrolides through kinetic parameters in bronchoalveolar lavage fluid (BALF) of lipopolysaccharide-induced lung injury. Rats were divided into four groups: lipopolysaccharide (LPS), LPS + tylosin, LPS + tilmicosin and LPS + tulathromycin. BALF samples were collected at sampling times. TNF, IL-1β, IL-6, IL-10 and 13,14-dihydro-15-keto-prostaglandin F2α (PGM) and C-reactive protein (CRP) were analysed. Area under the curve (AUC) and maximum plasma concentration (Cmax) values of inflammatory mediators were determined by a pharmacokinetic computer programme. When inflammatory mediator concentrations were compared between the LPS group and other groups for each sampling time, the three macrolides had no pronounced depressor effect on cytokine levels, but they depressed PGM and CRP levels. In addition, tylosin and tilmicosin decreased the AUC0-24 level of TNF, while tilmicosin decreased the AUC0-24 level of IL-10. Tylosin and tulathromycin decreased the AUC0-24 of PGM, and all three macrolides decreased the AUC0-24 of CRP. Especially tylosin and tulathromycin may have more expressed anti-inflammatory effects than tilmicosin, via depressing the production of inflammatory mediators in the lung. The AUC may be used for determining the effects of drugs on inflammation. In this study, the antiinflammatory effects of these antibiotics were evaluated with kinetic parameters as a new and different approach.

  6. Electrically Controllable Microparticle Synthesis and Digital Microfluidic Manipulation by Electric-Field-Induced Droplet Dispensing into Immiscible Fluids

    Science.gov (United States)

    Um, Taewoong; Hong, Jiwoo; Im, Do Jin; Lee, Sang Joon; Kang, In Seok

    2016-08-01

    The dispensing of tiny droplets is a basic and crucial process in a myriad of applications, such as DNA/protein microarray, cell cultures, chemical synthesis of microparticles, and digital microfluidics. This work systematically demonstrates droplet dispensing into immiscible fluids through electric charge concentration (ECC) method. It exhibits three main modes (i.e., attaching, uniform, and bursting modes) as a function of flow rates, applied voltages, and gap distances between the nozzle and the oil surface. Through a conventional nozzle with diameter of a few millimeters, charged droplets with volumes ranging from a few μL to a few tens of nL can be uniformly dispensed into the oil chamber without reduction in nozzle size. Based on the features of the proposed method (e.g., formation of droplets with controllable polarity and amount of electric charge in water and oil system), a simple and straightforward method is developed for microparticle synthesis, including preparation of colloidosomes and fabrication of Janus microparticles with anisotropic internal structures. Finally, a combined system consisting of ECC-induced droplet dispensing and electrophoresis of charged droplet (ECD)-driven manipulation systems is constructed. This integrated platform will provide increased utility and flexibility in microfluidic applications because a charged droplet can be delivered toward the intended position by programmable electric control.

  7. Hydroferrate fluid, MRN-100, provides protection against chemical-induced gastric and esophageal cancer in Wistar rats.

    Science.gov (United States)

    Ghoneum, Mamdooh H; Badr El-Din, Nariman K; Abdel Fattah, Salma M; Pan, Deyu; Tolentino, Lucilene

    2015-01-01

    In the current study, we examined the protective effect of hydroferrate fluid MRN-100 against the carcinogen methylnitronitrosoguanidine (MNNG)-induced gastric and esophageal cancer in rats. MRN-100 is an iron-based compound composed of bivalent and trivalent ferrates. At 33 weeks post treatment with MNNG, rats were killed and examined for the histopathology of esophagus and stomach; liver, spleen, and total body weight; and antioxidant levels in the blood and stomach tissues. Results showed that 17/20 (85%) gastroesophageal tissues from carcinogen MNNG-treated rats developed dysplasia and cancer, as compared to 8/20 (40%) rats treated with MNNG plus MRN-100. In addition, MRN-100 exerted an antioxidant effect in both the blood and stomach tissues by increasing levels of GSH, antioxidant enzymes SOD, CAT, and GPx, and total antioxidant capacity (TAC) level. This was accompanied by a reduction in the total free-radical and malondialdehyde levels. Furthermore, MRN-100 protected against body and organ weight loss. Thus, MRN-100 exhibited significant cancer chemopreventive activity by protecting tissues against oxidative damage in rats, which may suggest its effectiveness as an adjuvant for the treatment of gastric/esophageal carcinoma.

  8. Ascaris lumbricoides pseudocoelomic body fluid induces a partially activated dendritic cell phenotype with Th2 promoting ability in vivo.

    Science.gov (United States)

    Dowling, David J; Noone, Cariosa M; Adams, Paul N; Vukman, Krisztina V; Molloy, Sile F; Forde, Jessica; Asaolu, Samuel; O'Neill, Sandra M

    2011-02-01

    Dendritic cells (DCs) matured with helminth-derived molecules that promote Th2 immune responses do not follow conventional definitions of DC maturation processes. While a number of models of DC maturation by Th2 stimuli are postulated, further studies are required if we are to clearly define DC maturation processes that lead to Th2 immune responses. In this study, we examine the interaction of Th2-inducing molecules from the parasitic helminth Ascaris lumbricoides with the maturation processes and function of DCs. Here we show that murine bone marrow-derived DCs are partially matured by A. lumbricoides pseudocoelomic body fluid (ABF) as characterised by the production of IL-6, IL-12p40 and macrophage inflammatory protein 2 (MIP-2) but no enhanced expression of cluster of differentiation (CD)-14, T-cell co-stimulatory markers CD80, CD86, CD40, OX40L and major histocompatibility complex class II was observed. Despite these phenotypic characteristics, ABF-stimulated DCs displayed the functional hallmarks of fully matured cells, enhancing DC phagocytosis and promoting Th2-type responses in skin-draining lymph node cells in vivo. ABF activated Th2-associated extracellular signal-regulated kinase-1 and nuclear factor-kB intracellular signalling pathways independently of toll-like receptor 4. Taken together, we believe this is the first paper to demonstrate A. lumbricoides murine DC-Th cell-driven responses shedding further light on DC maturation processes by helminth antigens.

  9. Electrically Controllable Microparticle Synthesis and Digital Microfluidic Manipulation by Electric-Field-Induced Droplet Dispensing into Immiscible Fluids

    Science.gov (United States)

    Um, Taewoong; Hong, Jiwoo; Kang, In Seok

    2016-11-01

    The dispensing of tiny droplets is a basic and crucial process in a myriad of applications, such as DNA/protein microarray, cell cultures, chemical synthesis of microparticles, and digital microfluidics. This work demonstrates the droplet dispensing into immiscible fluids through electric charge concentration (ECC) method. Three main modes (i.e., attaching, uniform and bursting modes) are exhibited as a function of flow rates, applied voltage and gap distance between the nozzle and the oil surface. Through a conventional nozzle with diameter of a few millimeters, charged droplets with volumes ranging from a few μL to a few tens of nL can be uniformly dispensed into the oil chamber without reduction in nozzle size. Based on the features of the proposed method (e.g., formation of droplets with controllable polarity and amount of electric charge in water and oil system), a simple and straightforward method is developed for microparticle synthesis, including preparation for colloidosomes and fabrication of Janus microparticles with anisotropic internal structures. Finally, a combined system consisting of ECC-induced droplet dispensing and electrophoresis of charged droplet (ECD)-driven manipulation systems is constructed. This work was supported by the BK21Plus Program for advanced education of creative chemical engineers of the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP).

  10. Semianalytical Solution for the Deformation of an Elastic Layer under an Axisymmetrically Distributed Power-Form Load: Application to Fluid-Jet-Induced Indentation of Biological Soft Tissues

    Science.gov (United States)

    Lu, Minhua; Huang, Shuai; Yang, Lei; Mao, Rui

    2017-01-01

    Fluid-jet-based indentation is used as a noncontact excitation technique by systems measuring the mechanical properties of soft tissues. However, the application of these devices has been hindered by the lack of theoretical solutions. This study developed a mathematical model for testing the indentation induced by a fluid jet and determined a semianalytical solution. The soft tissue was modeled as an elastic layer bonded to a rigid base. The pressure of the fluid jet impinging on the soft tissue was assumed to have a power-form function. The semianalytical solution was verified in detail using finite-element modeling, with excellent agreement being achieved. The effects of several parameters on the solution behaviors are reported, and a method for applying the solution to determine the mechanical properties of soft tissues is suggested. PMID:28373991

  11. Refrigerating fluids; Fluides frigorigenes

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1999-03-01

    Refrigerating fluids are experiencing a real revolution since few years. CFCs with their destructive effect on the ozone layer are now prohibited while HCFCs will be progressively eliminated and replaced by HFCs. However, HFCs can contribute to the increase of the greenhouse effect. The solutions proposed by thermal engineering professionals consist in the confinement of air-conditioning installations (elimination of recurrent leaks) and in the improvement of installations efficiency. HCFC fluids like the R 22 are still widely used in air-conditioning but they are supposed to be replaced by HFC fluids like the R 134a, the R 407C or the R 410A. This short paper gives a brief presentation of these fluids and of their chemical characteristics. (J.S.)

  12. An in vitro comparative study of intracanal fluid motion and wall shear stress induced by ultrasonic and polymer rotary finishing files in a simulated root canal model.

    Science.gov (United States)

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

  13. YghJ, the secreted metalloprotease of pathogenic E. coli induces hemorrhagic fluid accumulation in mouse ileal loop.

    Science.gov (United States)

    Tapader, Rima; Bose, Dipro; Pal, Amit

    2017-04-01

    YghJ, also known as SslE (Secreted and surface associated lipoprotein) is a cell surface associated and secreted lipoprotein harbouring M60 metalloprotease domain. Though the gene is known to be conserved among both pathogenic and commensal Escherichia coli isolates, the expression and secretion of YghJ was found to be higher among diverse E. coli pathotypes. YghJ, secreted from intestinal pathogens such as enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) has been demonstrated to possess mucinase activity and hence facilitates colonization of these enteric pathogens to intestinal epithelial cells. Importantly, YghJ is also reported to be secreted from extraintestinal pathogenic E. coli isolates. In our previous study we have shown that YghJ, purified from a neonatal septicemic E. coli isolate could trigger induction of various proinflammatory cytokines in vitro. This led us to investigate the role of YghJ in causing in vivo tissue hemorrhage. In the present study, we validate the earlier in vitro finding and have showed that YghJ can cause extensive tissue damage in mouse ileum and is also able to induce significant fluid accumulation in a dose dependent manner in a mouse ileal loop (MIL) assay. Hence, our present study not only confirms the pathogenic potential of YghJ in sepsis pathophysiology but also indicates the enterotoxic ability of YghJ which makes it an important virulence determinant of intestinal pathogenic E. coli. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Enamel demineralization and remineralization under plaque fluid-like conditions: a quantitative light-induced fluorescence study.

    Science.gov (United States)

    Lippert, F; Butler, A; Lynch, R J M

    2011-01-01

    The present study investigated de- and remineralization in enamel lesions under plaque fluid (PF)-like conditions using quantitative light-induced fluorescence (QLF). Preformed lesions were exposed to partially saturated lactic acid solutions, varying in pH and fluoride concentration ([F]) based on a 5 × 3 factorial study design (0/0.1/0.5/1.5/4 ppm F; pH 4.9/5.2/5.5). Average fluorescence loss (ΔF) was monitored for 11 days. Subsequently, lesions were demineralized in a partially saturated acetic acid solution for two 24-hour periods. Data were analyzed using repeated measures analysis of covariance. Lesions exposed to PF at 4 ppm F and pH 5.5 showed not only the most remineralization (ΔΔF = 28.2 ± 14.0%) for all groups after 11 days, but also the most demineralization (ΔΔF = -19.3 ± 13.5%) after subsequent acetic acid exposure. Increased [F] resulted in more remineralization, regardless of pH. Higher pH values resulted in more remineralization. No remineralization was observed in lesions exposed to F-free solutions, regardless of pH. Remineralization was noticeable under the following conditions: pH 4.9 - [F] = 4 ppm, pH 5.2 - [F] ≥ 1.5 ppm, and pH 5.5 - [F] ≥ 0.5 ppm. Overall, [F] had a stronger effect on remineralization than pH. Subsequent demineralization showed that little protection was offered by PF-like solutions, and further demineralization compared with baseline was observed on lesions not remineralized initially. [F] had a stronger effect on net mineral change than pH. The present study has shown that QLF is a valuable tool in studying lesion de- and remineralization under PF-like conditions, where [F] was shown to be more important than pH.

  15. Amniotic fluid stem cells inhibit the progression of bleomycin-induced pulmonary fibrosis via CCL2 modulation in bronchoalveolar lavage.

    Directory of Open Access Journals (Sweden)

    Orquidea Garcia

    Full Text Available The potential for amniotic fluid stem cell (AFSC treatment to inhibit the progression of fibrotic lung injury has not been described. We have previously demonstrated that AFSC can attenuate both acute and chronic-fibrotic kidney injury through modification of the cytokine environment. Fibrotic lung injury, such as in Idiopathic Pulmonary Fibrosis (IPF, is mediated through pro-fibrotic and pro-inflammatory cytokine activity. Thus, we hypothesized that AFSC treatment might inhibit the progression of bleomycin-induced pulmonary fibrosis through cytokine modulation. In particular, we aimed to investigate the effect of AFSC treatment on the modulation of the pro-fibrotic cytokine CCL2, which is increased in human IPF patients and is correlated with poor prognoses, advanced disease states and worse fibrotic outcomes. The impacts of intravenous murine AFSC given at acute (day 0 or chronic (day 14 intervention time-points after bleomycin injury were analyzed at either day 3 or day 28 post-injury. Murine AFSC treatment at either day 0 or day 14 post-bleomycin injury significantly inhibited collagen deposition and preserved pulmonary function. CCL2 expression increased in bleomycin-injured bronchoalveolar lavage (BAL, but significantly decreased following AFSC treatment at either day 0 or at day 14. AFSC were observed to localize within fibrotic lesions in the lung, showing preferential targeting of AFSC to the area of fibrosis. We also observed that MMP-2 was transiently increased in BAL following AFSC treatment. Increased MMP-2 activity was further associated with cleavage of CCL2, rendering it a putative antagonist for CCL2/CCR2 signaling, which we surmise is a potential mechanism for CCL2 reduction in BAL following AFSC treatment. Based on this data, we concluded that AFSC have the potential to inhibit the development or progression of fibrosis in a bleomycin injury model during both acute and chronic remodeling events.

  16. Analysis of TNF-α-induced Leukocyte Adhesion to Vascular Endothelial Cells Regulated by Fluid Shear Stress Using Microfluidic Chip-based Technology

    Institute of Scientific and Technical Information of China (English)

    LI Yuan; YANG De-yu; LIAO Juan; GONG Fang; HE Ping; LIU Bei-zhong

    2015-01-01

    This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology. Microfluidic chip was fabricated by soft lithograph;Endothelial microfluidic chip was constructed by optimizing types of the extracellular matrix proteins modified in the microchannel and cell incubation time;human umbilical vein endothelial cells EA.Hy926 lined in the microchannel were exposed to fluid shear stress of 1.68 dynes/cm2 and 8.4 dynes/cm2 respectively. Meanwhile, adhesion between EA.Hy926 cells and leukocyte was induced by TNF-αunder a flow condition. EA. Hy926 cell cultured in the static condition was used as control group. The numbers of fluorescently-labeled leukocyte in microchannel were counted to quantize the adhesion level between EA. Hy926 cells and leukocyte; cell immunofluorescence technique was used to detect the intercellular adhesion molecule (ICAM-1) expression. The constructed endothelial microfluidic chip can afford to the fluid shear stress and respond to exogenous stimulus of TNF-α;compared with the adhesion numbers of leukocyte in control group, adhesion between EA. Hy926 cells exposed to low fluid shear stress and leukocyte was reduced under the stimulus of TNF-α at a concentration of 10 ng/ml(P<0.05);leukocyte adhesion with EA. Hy926 cells exposed to high fluid shear stress was reduced significantly than EA. Hy926 cells in control group and EA.1Hy926 cells exposed to low fluid shear stress ( P<0.01); the regulation mechanism of fluid shear stress to the adhesion between EA. Hy926 cells and leukocyte induced by TNF-αwas through the way of ICAM-1. The endothelial microfluidic chip fabricated in this paper could be used to study the functions of endothelial cell in vitro and provide a new technical platform for exploring the pathophysiology of the related cardiovascular system diseases under a flow environment.

  17. Lim Mineralization Protein 3 Induces the Osteogenic Differentiation of Human Amniotic Fluid Stromal Cells through Kruppel-Like Factor-4 Downregulation and Further Bone-Specific Gene Expression

    Directory of Open Access Journals (Sweden)

    Marta Barba

    2012-01-01

    Full Text Available Multipotent mesenchymal stem cells with extensive self-renewal properties can be easily isolated and rapidly expanded in culture from small volumes of amniotic fluid. These cells, namely, amniotic fluid-stromal cells (AFSCs, can be regarded as an attractive source for tissue engineering purposes, being phenotypically and genetically stable, plus overcoming all the safety and ethical issues related to the use of embryonic/fetal cells. LMP3 is a novel osteoinductive molecule acting upstream to the main osteogenic pathways. This study is aimed at delineating the basic molecular events underlying LMP3-induced osteogenesis, using AFSCs as a cellular model to focus on the molecular features underlying the multipotency/differentiation switch. For this purpose, AFSCs were isolated and characterized in vitro and transfected with a defective adenoviral vector expressing the human LMP3. LMP3 induced the successful osteogenic differentiation of AFSC by inducing the expression of osteogenic markers and osteospecific transcription factors. Moreover, LMP3 induced an early repression of the kruppel-like factor-4, implicated in MSC stemness maintenance. KLF4 repression was released upon LMP3 silencing, indicating that this event could be reasonably considered among the basic molecular events that govern the proliferation/differentiation switch during LMP3-induced osteogenic differentiation of AFSC.

  18. Amniotic fluid

    Science.gov (United States)

    ... carefully. Removing a sample of the fluid through amniocentesis can provide information about the sex, health, and development of the fetus. Images Amniocentesis Amniotic fluid Polyhydramnios Amniotic fluid References Cunningham FG, ...

  19. Changes of cytosolic [Ca2+]i in neutrophils in pancreatic microcirculation of rats with caerulein-induced acute pancreatitis under fluid shear stress

    Institute of Scientific and Technical Information of China (English)

    Zong-Guang Zhou; You-Qin Chen; Xu-Bao Liu; Wei-Ming Hu; Bo-Le Tian; Huai-Qing Chen

    2004-01-01

    AIM: To investigate the fluid shear stress induced changes of [Ca2+]i in neutrophils in pancreatic microcirculation of experimental acute pancreatitis (AP).METHODS: Wistar rats (n = 36) were randomized into three groups. A model of AP was established by subcutaneous injection of caerulein. Low-shear 30 viscometer was used to provide steady fluid shear stress on separated neutrophils.The mean fluorescent intensity tested by flow cytometry was used as the indication of [Ca2+]i quantity.RESULTS: Under steady shear, cytosolic [Ca2+]i showed biphasic changes. The shear rate changed from low to high,[Ca2+]i in different groups decreased slightly and then increased gradually to a high level (P<0.05). A close correlation was observed between the cytosolic [Ca2+]i level and the alteration of fluid shear stress in regional microcirculation of AP.CONCLUSION: The increase of [Ca2+]i is highly related to the activation of neutrophils, which contributes to neutrophil adhesion to endothelium in the early phase of AP. The effect of fluid shear stress on [Ca2+]i may play a crucial role in pancreatic microcirculatory failure of AP.

  20. Influence of induced magnetic field and heat transfer on the peristaltic motion of a Jeffrey fluid in an asymmetric channel: Closed form solutions

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Safia, E-mail: safia_akram@yahoo.com [Department of Humanities and Basic Sciences, Military College of Signals, National University of Sciences and Technology, Rawalpindi 46000 (Pakistan); Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan); Nadeem, S. [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan)

    2013-02-15

    We discuss the peristaltic motion of a two dimensional Jeffrey fluid in an asymmetric channel under the effects of induced magnetic field and heat transfer. The problem is simplified by using long wave length and low Reynolds approximations. Exact and closed form Adomian solutions are presented. Expressions for the velocity, stream function, magnetic force function, temperature, pressure gradient and pressure rise are computed. The results of pertinent parameters are discussed. Finally, the trapping phenomena for different wave shapes are discussed. It is observed that the pressure rise for sinusoidal wave is less than trapezoidal wave and greater than triangular in a Jeffrey fluid. - Highlights: Black-Right-Pointing-Pointer The effects of induced magnetic field and heat transfer in peristaltic motion of a two dimensional Jeffrey fluid are discussed. Black-Right-Pointing-Pointer In this paper exact and closed form Adomian solutions are presented. Black-Right-Pointing-Pointer Different wave shapes are considered to observe the behavior of pressure rise and trapping phenomena.

  1. Colloidal Stability and Magnetic Field-Induced Ordering of Magnetorheological Fluids Studied with a Quartz Crystal Microbalance

    Directory of Open Access Journals (Sweden)

    Jaime Rodriguez-López

    2015-12-01

    Full Text Available This work proposes the use of quartz crystal microbalances (QCMs as a method to analyze and characterize magnetorheological (MR fluids. QCM devices are sensitive to changes in mass, surface interactions, and viscoelastic properties of the medium contacting its surface. These features make the QCM suitable to study MR fluids and their response to variable environmental conditions. MR fluids change their structure and viscoelastic properties under the action of an external magnetic field, this change being determined by the particle volume fraction, the magnetic field strength, and the presence of thixotropic agents among other factors. In this work, the measurement of the resonance parameters (resonance frequency and dissipation factor of a QCM are used to analyze the behavior of MR fluids in static conditions (that is, in the absence of external mechanical stresses. The influence of sedimentation under gravity and the application of magnetic fields on the shifts of resonance frequency and dissipation factor were measured and discussed in the frame of the coupled resonance produced by particles touching the QCM surface. Furthermore, the MR-fluid/QCM system has a great potential for the study of high-frequency contact mechanics because the translational and rotational stiffness of the link between the surface and the particles can be tuned by the magnetic field.

  2. Parametric study of the vibration-induced repulsion or attraction force on a particle in a viscous fluid cell.

    Science.gov (United States)

    Saadatmand, Mehrrad; Kawaji, Masahiro

    2014-04-01

    Experiments and three-dimensional direct numerical simulations were performed to investigate the effects of physical parameters on the repulsion or attraction force affecting the motion of a particle oscillating near a solid wall of a fluid cell under microgravity. The following physical parameters were investigated: fluid cell amplitude, fluid and particle densities, angular frequency of the cell vibration, initial distance between the particle centroid and the closest cell wall, particle radius, and dynamic viscosity. Based on the simulations, a nondimensional relation was developed to relate those physical parameters to the repulsion or attraction force affecting the particle. The relation shows that the repulsion or attraction force is increased by the increase in the cell vibration amplitude and frequency and also the force direction would change from attraction to repulsion above a threshold fluid viscosity. Relations to other physical parameters were also studied and are reported. This paper follows our previous work on the physical mechanism of observed repulsion force on a particle in a viscous fluid cell [M. Saadatmand and M. Kawaji, Phys. Rev. E 88, 023019 (2013)].

  3. Mueller-matrix of laser-induced autofluorescence of polycrystalline films of dried peritoneal fluid in diagnostics of endometriosis

    Science.gov (United States)

    Ushenko, Yuriy A.; Koval, Galina D.; Ushenko, Alexander G.; Dubolazov, Olexander V.; Ushenko, Vladimir A.; Novakovskaia, Olga Yu.

    2016-07-01

    This research presents investigation results of the diagnostic efficiency of an azimuthally stable Mueller-matrix method of analysis of laser autofluorescence of polycrystalline films of dried uterine cavity peritoneal fluid. A model of the generalized optical anisotropy of films of dried peritoneal fluid is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase (linear and circular birefringence) and amplitude (linear and circular dichroism) anisotropies is taken into consideration. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistical analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the first to the fourth order) of differentiation of polycrystalline films of dried peritoneal fluid, group 1 (healthy donors) and group 2 (uterus endometriosis patients), are determined.

  4. The flow of a non-Newtonian fluid induced due to the oscillations of a porous plate

    Directory of Open Access Journals (Sweden)

    S. Asghar

    2004-01-01

    Full Text Available An analytic solution of the flow of a third-grade fluid on a porous plate is constructed. The porous plate is executing oscillations in its own plane with superimposed injection or suction. An increasing or decreasing velocity amplitude of the oscillating porous plate is also examined. It is also shown that in case of third-grade fluid, a combination of suction/injection and decreasing/increasing velocity amplitude is possible as well. Several limiting situations with their implications are given and discussed.

  5. Experimental study on pressure, stress state, and temperature-dependent dynamic behavior of shear thickening fluid subjected to laser induced shock

    Science.gov (United States)

    Wu, Xianqian; Yin, Qiuyun; Huang, Chenguang

    2015-11-01

    The dynamic response of the 57 vol./vol. % dense spherical silica particle-polyethylene glycol suspension at high pressure was investigated through short pulsed laser induced shock experiments by measuring the back free surface velocities of aluminum-shear thickening fluid (STF)-aluminum assembled targets. The results showed that the attenuation behavior of shock wave in the STF was dependent on shock pressure, stress state, and test temperature. The measured back free particle velocities of the targets and shock wave velocities in the STF decreased with the decrease in shock pressure while shocked at the same stress state and the same test temperature. In addition, two types of dragging mechanisms in the STF were observed while shocked at different stress states. For a uniaxial strain state, the impact induced jamming behavior in the STF is the dragging mechanism for the attenuation of shock wave, and a critical shock pressure was required for the impact induced thickening behavior. However, while the shock wave transformed from a uniaxial strain state to a dilatation state after transmitted to a certain distance, beside the dragging effect of impact induced jamming behavior, a strong dragging effect, induced by shear induced thickening behavior, was also observed.

  6. Low Fluid Shear Culture of Staphylococcus Aureus Represses hfq Expression and Induces an Attachment-Independent Biofilm Phenotype

    Science.gov (United States)

    Ott, C. Mark; Castro, S. L.; Nickerson, C. A.; Nelman-Gonzalez, M.

    2011-01-01

    Background: The opportunistic pathogen, Staphylococcus aureus, experiences fluctuations in fluid shear during infection and colonization of a human host. Colonization frequently occurs at mucus membrane sites such as in the gastrointestinal tract where the bacterium may experience low levels of fluid shear. The response of S. aureus to low fluid shear remains unclear. Methods: S. aureus was cultured to stationary phase using Rotating-Wall Vessel (RWV) bioreactors which produce a physiologically relevant low fluid shear environment. The bacterial aggregates that developed in the RWV were evaluated by electron microscopy as well as for antibiotic resistance and other virulence-associated stressors. Genetic expression profiles for the low-shear cultured S. aureus were determined by microarray analysis and quantitative real-time PCR. Results: Planktonic S. aureus cultures in the low-shear environment formed aggregates completely encased in high amounts of extracellular polymeric substances. In addition, these aggregates demonstrated increased antibiotic resistance indicating attachment-independent biofilm formation. Carotenoid production in the low-shear cultured S. aureus was significantly decreased, and these cultures displayed an increased susceptibility to oxidative stress and killing by whole blood. The hfq gene, associated with low-shear growth in Gram negative organisms, was also found to be down-regulated in S. aureus. Conclusions: Collectively, this data suggests that S. aureus decreases virulence characteristics in favor of a biofilm-dwelling colonization phenotype in response to a low fluid shear environment. Furthermore, the identification of an Hfq response to low-shear culture in S. aureus, in addition to the previously reported responses in Gram negative organisms, strongly suggests an evolutionarily conserved response to mechanical stimuli among structurally diverse prokaryotes.

  7. Cerebrospinal fluid real-time quaking-induced conversion is a robust and reliable test for sporadic creutzfeldt-jakob disease: An international study.

    Science.gov (United States)

    McGuire, Lynne I; Poleggi, Anna; Poggiolini, Ilaria; Suardi, Silvia; Grznarova, Katarina; Shi, Song; de Vil, Bart; Sarros, Shannon; Satoh, Katsuya; Cheng, Keding; Cramm, Maria; Fairfoul, Graham; Schmitz, Matthias; Zerr, Inga; Cras, Patrick; Equestre, Michele; Tagliavini, Fabrizio; Atarashi, Ryuichiro; Knox, David; Collins, Steven; Haïk, Stéphane; Parchi, Piero; Pocchiari, Maurizio; Green, Alison

    2016-07-01

    Real-time quaking-induced conversion (RT-QuIC) has been proposed as a sensitive diagnostic test for sporadic Creutzfeldt-Jakob disease; however, before this assay can be introduced into clinical practice, its reliability and reproducibility need to be demonstrated. Two international ring trials were undertaken in which a set of 25 cerebrospinal fluid samples were analyzed by a total of 11 different centers using a range of recombinant prion protein substrates and instrumentation. The results show almost complete concordance between the centers and demonstrate that RT-QuIC is a suitably reliable and robust technique for clinical practice. Ann Neurol 2016;80:160-165.

  8. Cerebrospinal fluid real‐time quaking‐induced conversion is a robust and reliable test for sporadic creutzfeldt–jakob disease: An international study

    Science.gov (United States)

    McGuire, Lynne I.; Poleggi, Anna; Poggiolini, Ilaria; Suardi, Silvia; Grznarova, Katarina; Shi, Song; de Vil, Bart; Sarros, Shannon; Satoh, Katsuya; Cheng, Keding; Cramm, Maria; Fairfoul, Graham; Schmitz, Matthias; Zerr, Inga; Cras, Patrick; Equestre, Michele; Tagliavini, Fabrizio; Atarashi, Ryuichiro; Knox, David; Collins, Steven; Haïk, Stéphane; Parchi, Piero; Pocchiari, Maurizio

    2016-01-01

    Real‐time quaking‐induced conversion (RT‐QuIC) has been proposed as a sensitive diagnostic test for sporadic Creutzfeldt–Jakob disease; however, before this assay can be introduced into clinical practice, its reliability and reproducibility need to be demonstrated. Two international ring trials were undertaken in which a set of 25 cerebrospinal fluid samples were analyzed by a total of 11 different centers using a range of recombinant prion protein substrates and instrumentation. The results show almost complete concordance between the centers and demonstrate that RT‐QuIC is a suitably reliable and robust technique for clinical practice. Ann Neurol 2016;80:160–165 PMID:27130376

  9. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  10. A comparison of boundary element and finite element methods for modeling axisymmetric polymeric drop deformation

    NARCIS (Netherlands)

    Hooper, Russell; Toose, E.M.; Macosko, Christopher W.; Derby, Jeffrey J.

    2001-01-01

    A modified boundary element method (BEM) and the DEVSS-G finite element method (FEM) are applied to model the deformation of a polymeric drop suspended in another fluid subjected to start-up uniaxial extensional flow. The effects of viscoelasticity, via the Oldroyd-B differential model, are

  11. Uma nova metodologia para a simulação de escoamentos de fluidos viscoelásticos A new approach for simulation of viscoelastic fluid flows

    Directory of Open Access Journals (Sweden)

    André R. Muniz

    2005-03-01

    Full Text Available É proposta neste trabalho uma nova metodologia para resolução das equações governantes de fluidos viscoelásticos, baseada no método dos volumes finitos, usando o arranjo co-localizado para as variáveis e malhas estruturadas. São utilizadas aproximações de alta ordem para os fluxos lineares e não-lineares médios nas interfaces dos volumes, e para os termos não-lineares que surgem da discretização das equações constitutivas. Nesta metodologia, os valores médios das variáveis nos volumes são usados durante todo o procedimento de resolução, e os valores pontuais são obtidos ao final, através da deconvolução dos valores médios. O sistema de equações discretizadas é resolvido de forma simultânea, pelo método de Newton. A metodologia é exemplificada para um problema clássico em mecânica de fluidos computacional, o escoamento stick-slip, usando como equação constitutiva o modelo de Oldroyd-B. As soluções obtidas apresentaram boa precisão, sendo livres de oscilações mesmo em regiões de grandes gradientes das variáveis.In this work, a new methodology to solve the governing equations of viscoelastic fluid flows is proposed. This methodology is based on the finite-volume method with co-located arrangement of the variables, using high-order approximations for the linear and nonlinear average fluxes in the interfaces and for the nonlinear terms resulting from the discretization of the constitutive equations. In this methodology, the average values of the variable in the volumes are used during the resolution, and the point values are recovered in the post-processing step by deconvolution of the average values. The nonlinear equations, resulting from the discretization technique, are solved simultaneously, using the Newton's method. The solutions obtained are oscillation-free and accurate, as can be seen in the solution of the stick-slip flow, used as an illustrative example.

  12. miRNA expression profile during fluid shear stress-induced osteogenic differentiation in MC3T3-E1 cells

    Institute of Scientific and Technical Information of China (English)

    MAI Zhi-hui; PENG Zhu-li; ZHANG Jing-lan; CHEN Lin; LIANG Huan-you; CAI Bin; AI Hong

    2013-01-01

    Background Mechanical stress plays an important role in the maintenance of bone homeostasis.Current hypotheses suggest that interstitial fluid flow is an important component of the system by which tissue level strains are amplified in bone.This study aimed to test the hypothesis that the short-term and appropriate fluid shear stress (FSS) is expected to promote the terminal differentiation of pre-osteoblasts and detect the expression profile of microRNAs in the FSS-induced osteogenic differentiation in MC3T3-E1 cells.Methods MC3T3-E1 cells were subjected to 1 hour of FSS at 12 dyn/cm2 using a parallel plate flow system.After FSS treatment,cytoskeleton immunohistochemical staining and microRNAs (miRNAs) were detected immediately.Osteogenic gene expression and immunohistochemical staining for collagen type Ⅰ were tested at the 24th hour after treatment,alkaline phosphatase (ALP) activity assay was performed at 24th,48th,and 72th hours after FSS treatment,and Alizarin Red Staining was checked at day 12.Results One hour of FSS at 12 dyn/cm2 induced actin stress fiber formation and rearrangement,up-regulated osteogenic gene expression,increased ALP activity,promoted synthesis and secretion of type Ⅰ collagen,enhanced nodule formation,and promoted terminal differentiation in MC3T3-E1 cells.During osteogenic differentiation,expression levels of miR-20a,-21,-19b,-34a,-34c,-140,and-200b in FSS-induced cells were significantly down-regulated.Conclusion The short-term and appropriate FSS is sufficient to promote terminal differentiation of pre-osteoblasts and a group of miRNAs may be invovled in FSS-induced pre-osteoblast differentiation.

  13. Oncogenic KRas-induced Increase in Fluid-phase Endocytosis is Dependent on N-WASP and is Required for the Formation of Pancreatic Preneoplastic Lesions.

    Science.gov (United States)

    Lubeseder-Martellato, Clara; Alexandrow, Katharina; Hidalgo-Sastre, Ana; Heid, Irina; Boos, Sophie Luise; Briel, Thomas; Schmid, Roland M; Siveke, Jens T

    2017-02-01

    Fluid-phase endocytosis is a homeostatic process with an unknown role in tumor initiation. The driver mutation in pancreatic ductal adenocarcinoma (PDAC) is constitutively active KRas(G12D), which induces neoplastic transformation of acinar cells through acinar-to-ductal metaplasia (ADM). We have previously shown that KRas(G12D)-induced ADM is dependent on RAC1 and EGF receptor (EGFR) by a not fully clarified mechanism. Using three-dimensional mouse and human acinar tissue cultures and genetically engineered mouse models, we provide evidence that (i) KRas(G12D) leads to EGFR-dependent sustained fluid-phase endocytosis (FPE) during acinar metaplasia; (ii) variations in plasma membrane tension increase FPE and lead to ADM in vitro independently of EGFR; and (iii) that RAC1 regulates ADM formation partially through actin-dependent regulation of FPE. In addition, mice with a pancreas-specific deletion of the Neural-Wiskott-Aldrich syndrome protein (N-WASP), a regulator of F-actin, have reduced FPE and impaired ADM emphasizing the in vivo relevance of our findings. This work defines a new role of FPE as a tumor initiating mechanism.

  14. Reduced-order modeling of fluid-structure interaction and vortex-induced vibration systems using an extension of Jourdain's principle

    Science.gov (United States)

    Mottaghi, S.; Benaroya, H.

    2016-11-01

    A first-principles variational approach is proposed for reduced-order modeling of fluid-structure interaction (FSI) systems, specifically vortex-induced vibration (VIV). FSI has to be taken into account in the design and analysis of many engineering applications, yet a comprehensive theoretical development where analytical equations are derived from first principles is nonexistent. An approach where Jourdain's principle is modified and extended for FSI is used to derive reduced-order models from an extended variational formulation where assumptions are explicitly stated. Two VIV models are considered: an elastically supported, inverted pendulum and a translating cylinder, both immersed in a flow and allowed to move transversely to the flow direction. Their reduced-order models are obtained in the form of (i) a single governing equation and (ii) two general coupled equations as well as the coupled lift-oscillator model. Comparisons are made with three existing models. Based on our theoretical results, and especially the reduced-order model, we conclude that the first principles development herein is a viable framework for the modeling of complex fluid-structure interaction problems such as vortex-induced oscillations.

  15. Flow induced particle migration in fresh concrete: Theoretical frame, numerical simulations and experimental results on model fluids

    DEFF Research Database (Denmark)

    Spangenberg, J.; Roussel, N.; Hattel, J.H.;

    2012-01-01

    In this paper, we describe and compare the various physical phenomena which potentially lead to flow induced particle migration in concrete. We show that, in the case of industrial casting of concrete, gravity induced particle migration dominates all other potential sources of heterogeneities ind...

  16. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  17. Fluid Interfaces

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    2001-01-01

    Fluid interaction, interaction by the user with the system that causes few breakdowns, is essential to many user interfaces. We present two concrete software systems that try to support fluid interaction for different work practices. Furthermore, we present specificity, generality, and minimality...... as design goals for fluid interfaces....

  18. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  19. Evidence for impact induced pressure gradients on the Allende CV3 parent body: Consequences for fluid and volatile transport

    Science.gov (United States)

    Tait, Alastair W.; Fisher, Kent R.; Srinivasan, Poorna; Simon, Justin I.

    2016-11-01

    Carbonaceous chondrites, such as those associated with the Vigarano (CV) parent body, exhibit a diverse range of oxidative/reduced alteration mineralogy (McSween, 1977). Although fluids are often cited as the medium by which this occurs (Rubin, 2012), a mechanism to explain how this fluid migrates, and why some meteorite subtypes from the same planetary body are more oxidized than others remains elusive. In our study we examined a slab of the well-known Allende (CV3OxA) meteorite. Using several petrological techniques (e.g., Fry's and Flinn) and Computerized Tomography (CT) we discover it exhibits a strong penetrative planar fabric, resulting from strain partitioning among its major components: Calcium-Aluminum-rich Inclusions (CAIs) (64.5%CT) > matrix (21.5%Fry) > chondrules (17.6%CT). In addition to the planar fabric, we found a strong lineation defined by the alignment of the maximum elongation of flattened particles interpreted to have developed by an impact event. The existence of a lineation could either be non-coaxial deformation, or the result of a mechanically heterogeneous target material. In the later case it could have formed due to discontinuous patches of sub-surface ice and/or fabrics developed through prior impact compaction (MacPherson and Krot, 2014), which would have encouraged preferential flow within the target material immediately following the impact, compacting pore spaces. We suggest that structurally controlled movement of alteration fluids in the asteroid parent body along pressure gradients contributed to the formation of secondary minerals, which may have ultimately lead to the different oxidized subtypes.

  20. Monitoring in situ deformation induced by a fluid injection in a fault zone in shale using seismic velocity changes

    Science.gov (United States)

    Rivet, D.; De Barros, L.; Guglielmi, Y.; Castilla, R.

    2015-12-01

    We monitor seismic velocity changes during an experiment at decametric scale aimed at artificially reactivate a fault zone by a high-pressure hydraulic injection in a shale formation of the underground site of Tournemire, South of France. A dense and a multidisciplinary instrumentation, with measures of pressure, fluid flow, strain, seismicity, seismic properties and resistivity allow for the monitoring of this experiment. We couple hydromechanical and seismic observations of the fault and its adjacent areas to better understand the deformation process preceding ruptures, and the role played by fluids. 9 accelerometers recorded repeated hammers shots on the tunnel walls. For each hammer shot we measured small travel time delays on direct P and S waves. We then located the seismic velocity perturbations using a tomography method. At low injection pressure, i.e. Pchange in S waves velocity. When the pressure overcomes 15 Bars, velocity perturbations dramatically increase with both P and S waves affected. A decrease of velocity is observed close to the injection point and is surrounded by regions of increasing velocity. Our observations are consistent with hydromechanical measures. Below 15 Bars, we interpret the P-wave velocity increase to be related to the compression of the fault zone around the injection chamber. Above 15 Bars, we measure a shear and dilatant fault movement, and a rapid increase in the injected fluid flow. At this step, our measures are coherent with a poroelastic opening of the fault with velocities decrease at the injection source and velocities increase related to stress transfer in the far field. Velocity changes prove to be efficient to monitor stress/strain variation in an activated fault, even if these observations might produce complex signals due to the highly contrasted hydromechanical responses in a heterogeneous media such as a fault zone.

  1. Fluid transport due to nonlinear fluid-structure interaction

    Energy Technology Data Exchange (ETDEWEB)

    Soendergaard Jensen, J.

    1996-08-01

    This work considers nonlinear fluid-structure interaction for a vibrating pipe containing fluid. Transverse pipe vibrations will force the fluid to move relative to the pipe creating uni-directional fluid flow towards the pipe end. The fluid flow induced affects the damping and the stiffness of the pipe. The behavior of the system in response to lateral resonant base excitation is analyzed numerically mode of vibration seems to be most effective for high mean fluid speed, whereas higher modes of vibration can be used to transport fluid with the same fluid speed but with smaller magnitude of pipe vibrations. The effect of the nonlinear geometrical terms is analyzed and these terms are shown to affect the response for higher modes of vibration. Experimental investigations show good agreement with theoretical predictions. (au) 16 refs.

  2. Changes of dynamical balance of free radicals induced by levodopa in rat glia-containing mesencephalic culture fluid

    Institute of Scientific and Technical Information of China (English)

    Wenxia Li; Shenggang Sun; Jingru Wang; Baoliang Sun; Yanbo Zhang

    2006-01-01

    BACKGROUND: Parkinson disease is neurodegenerative disorders, characterized by a progressive and selective degeneration of nigrostriatal dopaminergic pathway. Its main clinical symptoms include bradykinesia, rigidity, rest tremor and disturbances in balance. Levodopa (L-DOPA) is the "gold standard" for the symptomatic treat ment of Parkinson disease, but L-DOPA is toxic to dopaminergic neurons and the chronic administration of L-DOPA often causes the side effects of motor such as "on-off ", etc., and its mechanism still has not been completely clarified.OBJECTIVE: To observe the changes of the content of glutathione (GSH), activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) and content of malondialdehyde (MDA) in glia-containing mesencephalic culture fluid after L-DOPA of different concentrations were added.DESIGN: A comparative observation.SETTINGS: Department of Neurology, Affiliated Hospital of Taishan Medical University; Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. MATERIALS: The experiment was carried out in the Basic Research Institute, Taishan Medical University from December 2003 to September 2004. Ten postnatal newborn SD rats (within 2 days) were selected, either male or female. Fetal bovine serum (DMEM/F12) was from Gibco Company; L-DOPA and glial fibrillary acidic protein (GFAP) from Sigma Company. Kits for determination of GSH, GSH-Px, SOD and MDA were purchased from Nanjing Jiancheng Bioengineering Research Institute.METHODS : Glia-containing mesencephalic culture fluid were placed in 24-well culture plate, and L-DOPA of 50, 100 and 500 μmol/L was added to each group, the blank control group was also set. The glia-containing mesencephalic culture fluid selected at 4, 24, 48 and 72 hours respectively to determine the GSH content with colorimetric quantitative technique, GSH-Px activity with colorimetric method, SOD activity with xanthine oxidase method and MDA

  3. Hurst exponent used as a tool to differentiate between magmatic and fluid-induced processes as reflected in crystal geochemistry

    Science.gov (United States)

    Domonik, A.; Słaby, E.; Śmigielski, M.

    2012-04-01

    A self-similarity parameter, the Hurst exponent (H) (called also roughness exponent) has been used to show the long-range dependence of element behaviour during the processes. The H value ranges between 0 and 1; a value of 0.5 indicates a random distribution indistinguishable from noise. For values greater or less than 0.5, the system shows non-linear dynamics. H 0.5 corresponds to increasing persistence (less chaotic). Such persistence is characterized as an effect of a long-term memory, and thus by a large degree of positive correlation. In theory, the preceding data constantly affect the next in the whole temporal series. Applied to chaotic dynamics, the system shows a subtle sensitivity to initial conditions. The process can show some degree of chaos, due to local variations, but generally, the trend preserves its persistent character through time. If the exponent value is low, the process shows frequent and sudden reversals e.g. the trends of such a process show mutual negative correlation of the succeding values in the data series. Thus, the system can be described as having a high degree of deterministic chaos. Alkali feldspar megacrysts grown from mixed magmas and recrystallized due to interaction with fluids have been selected for the study (Słaby et al., 2011). Hurst exponent variability has been calculated within some primary-magmatic and secondary-recrystallized crystal domains for some elements redistributed by crystal fluid interaction. Based on the Hurst exponent value two different processes can easily be recognized. In the core of the megacrysts the element distribution can be ascribed to magmatic growth. By contrast, the marginal zones can relate to inferred late crystal-fluid interactions. Both processes are deterministic, not random. The spatial distribution of elements in the crystal margins is irregular, with high-H values identifying the process as persistent. The trace element distributions in feldspar cores are almost homogeneous and only

  4. Regulation of ENaC-mediated alveolar fluid clearance by insulin via PI3K/Akt pathway in LPS-induced acute lung injury

    Directory of Open Access Journals (Sweden)

    Deng Wang

    2012-03-01

    Full Text Available Abstract Background Stimulation of epithelial sodium channel (ENaC increases Na+ transport, a driving force of alveolar fluid clearance (AFC to keep alveolar spaces free of edema fluid that is beneficial for acute lung injury (ALI. It is well recognized that regulation of ENaC by insulin via PI3K pathway, but the mechanism of this signaling pathway to regulate AFC and ENaC in ALI remains unclear. The aim of this study was to investigate the effect of insulin on AFC in ALI and clarify the pathway in which insulin regulates the expression of ENaC in vitro and in vivo. Methods A model of ALI (LPS at a dose of 5.0 mg/kg with non-hyperglycemia was established in Sprague-Dawley rats receiving continuous exogenous insulin by micro-osmotic pumps and wortmannin. The lungs were isolated for measurement of bronchoalveolar lavage fluid(BALF, total lung water content(TLW, and AFC after ALI for 8 hours. Alveolar epithelial type II cells were pre-incubated with LY294002, Akt inhibitor and SGK1 inhibitor 30 minutes before insulin treatment for 2 hours. The expressions of α-,β-, and γ-ENaC were detected by immunocytochemistry, reverse transcriptase polymerase chain reaction (RT-PCR and western blotting. Results In vivo, insulin decreased TLW, enchanced AFC, increased the expressions of α-,β-, and γ-ENaC and the level of phosphorylated Akt, attenuated lung injury and improved the survival rate in LPS-induced ALI, the effects of which were blocked by wortmannin. Amiloride, a sodium channel inhibitor, significantly reduced insulin-induced increase in AFC. In vitro, insulin increased the expressions of α-,β-, and γ-ENaC as well as the level of phosphorylated Akt but LY294002 and Akt inhibitor significantly prevented insulin-induced increase in the expression of ENaC and the level of phosphorylated Akt respectively. Immunoprecipitation studies showed that levels of Nedd4-2 binding to ENaC were decreased by insulin via PI3K/Akt pathway. Conclusions Our study

  5. Geometry and subsidence history of the Dead Sea basin: A case for fluid-induced mid-crustal shear zone?

    Science.gov (United States)

    ten Brink, U.S.; Flores, C.H.

    2012-01-01

    Pull-apart basins are narrow zones of crustal extension bounded by strike-slip faults that can serve as analogs to the early stages of crustal rifting. We use seismic tomography, 2-D ray tracing, gravity modeling, and subsidence analysis to study crustal extension of the Dead Sea basin (DSB), a large and long-lived pull-apart basin along the Dead Sea transform (DST). The basin gradually shallows southward for 50 km from the only significant transverse normal fault. Stratigraphic relationships there indicate basin elongation with time. The basin is deepest (8-8.5 km) and widest (???15 km) under the Lisan about 40 km north of the transverse fault. Farther north, basin depth is ambiguous, but is 3 km deep immediately north of the lake. The underlying pre-basin sedimentary layer thickens gradually from 2 to 3 km under the southern edge of the DSB to 3-4 km under the northern end of the lake and 5-6 km farther north. Crystalline basement is ???11 km deep under the deepest part of the basin. The upper crust under the basin has lower P wave velocity than in the surrounding regions, which is interpreted to reflect elevated pore fluids there. Within data resolution, the lower crust below ???18 km and the Moho are not affected by basin development. The subsidence rate was several hundreds of m/m.y. since the development of the DST ???17 Ma, similar to other basins along the DST, but subsidence rate has accelerated by an order of magnitude during the Pleistocene, which allowed the accumulation of 4 km of sediment. We propose that the rapid subsidence and perhaps elongation of the DSB are due to the development of inter-connected mid-crustal ductile shear zones caused by alteration of feldspar to muscovite in the presence of pore fluids. This alteration resulted in a significant strength decrease and viscous creep. We propose a similar cause to the enigmatic rapid subsidence of the North Sea at the onset the North Atlantic mantle plume. Thus, we propose that aqueous fluid flux

  6. The roles of fluid transport and surface reaction in reaction-induced fracturing, with implications for the development of mesh textures in serpentinites

    Science.gov (United States)

    Shimizu, Hiroyuki; Okamoto, Atsushi

    2016-09-01

    The distinct element method was used to simulate chemical-mechanical-hydraulic processes that occur during serpentinization (volume-increasing hydration) within the oceanic lithosphere. The proposed model considers water transported in two ways: advective flow along fractures and through matrices. Variations in fracture pattern and system evolution were examined using two nondimensional parameters: the ratios of the rates of flow in fracture ( Ψ F) and matrix ( Ψ M) to the surface reaction rate. In cases of fixed Ψ F and Ψ M with sufficiently low reaction rates, the fracture pattern is not dependent on the surface reaction rate. Otherwise, the fracture pattern varies systematically as a function of Ψ F and Ψ M. At low Ψ F (≤1) and low Ψ M (≤1), the reaction proceeds from the boundaries inward and forms fine fractures layer by layer. At high Ψ F (≥10,000) and low Ψ M (≤10), the reaction proceeds from the boundaries inward and forms polygonal fracture networks. As Ψ M increases (>100), the reaction tends to proceed homogeneously from the boundaries without fracturing. A comparison of natural and simulated textures reveals that the following conditions are necessary to develop mesh textures during serpentinization in the oceanic lithosphere. (1) The surface reaction rate must be similar to or higher than the fluid flow rate in the matrix (or than the diffusive transport of water), and much lower than the fluid flow rate along fractures. (2) Original olivine grain boundaries act as pathways for fluid transport; these pathways may result from thermal or tectonic stress-induced cracking prior to serpentinization.

  7. An Integrated Model of the Cardiovascular and Central Nervous Systems for Analysis of Microgravity Induced Fluid Redistribution

    Science.gov (United States)

    Price, R.; Gady, S.; Heinemann, K.; Nelson, E. S.; Mulugeta, L.; Ethier, C. R.; Samuels, B. C.; Feola, A.; Vera, J.; Myers, J. G.

    2015-01-01

    A recognized side effect of prolonged microgravity exposure is visual impairment and intracranial pressure (VIIP) syndrome. The medical understanding of this phenomenon is at present preliminary, although it is hypothesized that the headward shift of bodily fluids in microgravity may be a contributor. Computational models can be used to provide insight into the origins of VIIP. In order to further investigate this phenomenon, NASAs Digital Astronaut Project (DAP) is developing an integrated computational model of the human body which is divided into the eye, the cerebrovascular system, and the cardiovascular system. This presentation will focus on the development and testing of the computational model of an integrated model of the cardiovascular system (CVS) and central nervous system (CNS) that simulates the behavior of pressures, volumes, and flows within these two physiological systems.

  8. Integration of phase separation with ultrasound-assisted salt-induced liquid-liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography.

    Science.gov (United States)

    Wang, Huili; Gao, Ming; Wang, Mei; Zhang, Rongbo; Wang, Wenwei; Dahlgren, Randy A; Wang, Xuedong

    2015-03-15

    Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on central composite design. Optimal conditions consisted of 945μL acetone extraction solvent, pH 2.1, 4.1min stir time, 5.9g Na2SO4, and 4.0min centrifugation. Under optimized conditions, the limits of detection (at S/N=3) were 0.12-0.66μgL(-1), the linear range was 0.5-500μgL(-1) and recoveries were 92.6-110.9% for the five FQs extracted from plasma and urine. The proposed method has several advantages, such as easy construction from inexpensive materials, high extraction efficiency, short extraction time, and compatibility with HPLC analysis. Thus, this method shows excellent prospects for sample pretreatment and analysis of FQs in human body fluids.

  9. Investigation of the motion of a viscous fluid in the vitreous cavity induced by eye rotations and implications for drug delivery

    Science.gov (United States)

    Bonfiglio, Andrea; Repetto, Rodolfo; Siggers, Jennifer H.; Stocchino, Alessandro

    2013-03-01

    Intravitreal drug delivery is a commonly used treatment for several retinal diseases. The objective of this research is to characterize and quantify the role of the vitreous humor motion, induced by saccadic movements, on drug transport processes in the vitreous chamber. A Perspex model of the human vitreous chamber was created, and filled with a purely viscous fluid, representing eyes with a liquefied vitreous humor or those containing viscous tamponade fluids. Periodic movements were applied to the model and the resulting three-dimensional (3D) flow fields were measured. Drug delivery within the vitreous chamber was investigated by calculating particle trajectories using integration over time of the experimental velocity fields. The motion of the vitreous humor generated by saccadic eye movements is intrinsically 3D. Advective mass transport largely overcomes molecular diffusive transport and is significantly anisotropic, leading to a much faster drug dispersion than in the case of stationary vitreous humor. Disregarding the effects of vitreous humor motion due to eye movements when predicting the efficiency of drug delivery treatments leads to significant underestimation of the drug transport coefficients, and this, in turn, will lead to significantly erroneous predictions of the concentration levels on the retina.

  10. Nonequilibrium Brownian dynamics analysis of negative viscosity induced in a magnetic fluid subjected to both ac magnetic and shear flow fields.

    Science.gov (United States)

    Morimoto, Hisao; Maekawa, Toru; Matsumoto, Yoichiro

    2002-06-01

    We study the rheological and magnetic characteristics of a magnetic fluid. The system, which we investigate, is as follows. Ferromagnetic particles are dispersed in a solvent, which is subjected to both ac magnetic and shear flow fields. The translational and rotational motions of particles are calculated by the Brownian dynamics method based on Langevin equations and the rheological and magnetic characteristics of the magnetic fluid system are estimated. First, we investigate the rheological and magnetic characteristics of the system in a dc magnetic field and then we analyze the effect of an ac magnetic field on those characteristics. We find that the negative viscosity effect is induced at a certain frequency range of the ac magnetic field. We also find that there are two main mechanisms responsible for the occurrence of negative viscosity. (1) Resonance between the rotational motions of the dipoles of particles and the fluctuation of ac magnetic fields occurs when applied magnetic fields are weak compared to the shear rate, in which case particles can still rotate in magnetic fields. Beyond this resonance frequency, negative viscosity appears. (2) The magnetic dipole moments of particles are forced to stay in the direction of the magnetic field when strong magnetic fields are applied in relatively low shear flow fields. However, negative viscosity occurs when the frequency of external magnetic fields exceeds a critical value, in which case the dipoles rotate continuously in a shear flow without stopping. In both cases, the mean angular velocity of the particles becomes higher than that of the solvent.

  11. Brain-derived neurotrophic factor and interleukin-6 levels in the serum and cerebrospinal fluid of children with viral infection-induced encephalopathy.

    Science.gov (United States)

    Morichi, Shinichiro; Yamanaka, Gaku; Ishida, Yu; Oana, Shingo; Kashiwagi, Yasuyo; Kawashima, Hisashi

    2014-11-01

    We investigated changes in the brain-derived neurotrophic factor (BDNF) and interleukin (IL)-6 levels in pediatric patients with central nervous system (CNS) infections, particularly viral infection-induced encephalopathy. Over a 5-year study period, 24 children hospitalized with encephalopathy were grouped based on their acute encephalopathy type (the excitotoxicity, cytokine storm, and metabolic error types). Children without CNS infections served as controls. In serum and cerebrospinal fluid (CSF) samples, BDNF and IL-6 levels were increased in all encephalopathy groups, and significant increases were noted in the influenza-associated and cytokine storm encephalopathy groups. Children with sequelae showed higher BDNF and IL-6 levels than those without sequelae. In pediatric patients, changes in serum and CSF BDNF and IL-6 levels may serve as a prognostic index of CNS infections, particularly for the diagnosis of encephalopathy and differentiation of encephalopathy types.

  12. Computational Fluid Dynamics and Experimental Study of Lock-in Phenomenon in Vortex-Induced Motions of a Cell-Truss Spar

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; YANG Jian-min; L(U) Hai-ning

    2009-01-01

    Spar platforms could be subject to vortex-induced-motions (VIM) in certain current conditions. Lock-in is a phenomenon which occurs in a range of reduced velocities in VIM. In this paper, a new concept of spar platform called cell-truss spar is studied using both computational fluid dynamics (CFD) and model test to investigate the VIM of the spar under different reduced velocities. The unique configuration of the cell-truss spar is carefully considered, and the unsteady flow around the spar is calculated and visualized in CFD simulations. A physical model with a scale ratio of 1:100 of the cell-truss spar is fabricated, and model tests are carried out in the current-generating ocean engineering basin. Many important parameters in VIM of the cell-truss spar are obtained, the occurrence of lock-in phenomenon is successfully simulated, and the mechanism and rules of lock-in are analyzed.

  13. Fluid mechanics

    CERN Document Server

    Kundu, Pijush K; Dowling, David R

    2011-01-01

    Fluid mechanics, the study of how fluids behave and interact under various forces and in various applied situations-whether in the liquid or gaseous state or both-is introduced and comprehensively covered in this widely adopted text. Revised and updated by Dr. David Dowling, Fluid Mechanics, 5e is suitable for both a first or second course in fluid mechanics at the graduate or advanced undergraduate level. Along with more than 100 new figures, the text has been reorganized and consolidated to provide a better flow and more cohesion of topics.Changes made to the

  14. On the interrelation of fluid-induced seismicity and crustal deformation at Columbo Seamount (Aegean Sea, Greece)

    Science.gov (United States)

    Hensch, M.; Dahm, T.; Hort, M.; Huebscher, C.; Dehghani, A.

    2009-04-01

    The Columbo submarine volcano is part of the Santorini volcanic complex, located in the center of the Hellenic volcanic arc, Aegean Sea, approximately 8km north-east of Santorini island. The Columbo seamount has attracted attention since island based monitoring indicated high seismicity rate and crustal deformation which both might be related to fluid migration in the subsurface. In addition to the island-based seismic network, 4 Ocean-Bottom-Seismometers (OBS) and 4 newly developed -Tiltmeters (OBT) have been deployed on top and in the vicinity of the seamount during the Columbo experiment between June 2006 and March 2007. Aim of the local experiment was to reduce the azimuthal gap between the islands, to get precise depth locations of the events and measuring tilt signals directly in the epicentral region. OBTs were additionally equipped with hydrophones to measure seismic signals and absolute pressure gauges to observe possible uplift or subsidence. A STA/LTA trigger applied to the seismic data delivered over 14.000 triggers for local and regional events over the whole deployment. At least 8 earthquake swarms with event rates of up to 230 events per day occurred during the experiment. First relocation results estimate a depth range between 5 and 15km for the seismic swarms. Centroids of these earthquake clusters are distributed beneath and in the vicinity of the Columbo caldera and SW of Columbo, in direction of Santorini volcano. Parallel to these sequences of seismic unrest, we observe long-period tilt signals occurring over several days or weeks, which might reflect slow, but permanent deformation at the seamount. Purpose of the study is to find evidences for swarm triggers, such as fluid migration, by precisely relocating the events by means of multiple event methods in order to investigate the migration behavior of the seismic clusters and by studying focal mechanisms of the events. In a second step, we compare observed tilt signals with the behavior of the

  15. Relatively light general anesthesia is more effective than fluid expansion in reducing the severity of epinephrine-induced hypotension during functional endoscopic sinus surgery

    Institute of Scientific and Technical Information of China (English)

    LI Wei-yan; ZHOU Zhi-qiang; JI Jun-feng; LI Ze-qing; YANG Jian-jun; SHANG Ruo-jing

    2007-01-01

    Background Epinephrine infiltration of the nasal mucosa causes hypotension during functional endoscopic sinus surgery (FESS) under general anesthesia. A prospective randomized-controlled study was designed to determine whether relatively light general anesthesia is superior to fluid expansion in reducing epinephrine-induced hypotension during FESS.Methods Ninety patients undergoing elective FESS under general anesthesia were randomly assigned to three groups with 30 patients in each. Each patient received local infiltration with adrenaline-containing (5 μg/ml) lidocaine (1%,4 ml) under different conditions. For Group Ⅰ, anesthesia was maintained with propofol 2 μg/ml and rimifentanil 2 ng/ml by TCI. Group Ⅱ (control group) and Group Ⅲ received propofol 4 μg/ml and rimifentanil 4 ng/ml, respectively. In Groups Ⅰ and Ⅱ, fluid expansion was performed with hetastarch 5 mi/kg within 20 minutes; hetastarch 10 ml/kg was used in Group Ⅲ. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 30-second-intervals for 5 minutes after the beginning of local infiltration. Simultaneously, the lowest and the highest MAP were recorded to calculate the mean maximum increase or decrease percent in MAP for all patients in each group. Data analysis was performed by χ2 test,one-way analysis of variance, or one-way analysis of covariance.Results Hemodynamic changes, particularly a decrease in MAP accompanied by an increase in HR at 1.5 minutes(P<0.05), were observed in all groups. The mean maximum decrease in MAP below baseline was 14% in Group Ⅰ, 24% in Group Ⅲ and 26% in Group Ⅱ. There were statistically significant differences between Group Ⅰ and Groups Ⅱ and Ⅲ(P<0.05). The mean maximum increase in MAP above baseline was 9% in Group Ⅰ, 6% in Group Ⅲ and 2% in Group Ⅱ.Conclusion Relatively light general anesthesia can reduce the severity of epinephrine-induced hypotension more effectively than fluid expansion during FESS under general

  16. Fluid transport due to nonlinear fluid-structure interaction

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    1997-01-01

    This work considers nonlinear fluid-structure interaction for a vibrating pipe containing fluid. Transverse pipe vibrations will force the fluid to move relative to the pipe creating unidirectional fluid flow towards the pipe end. The fluid flow induced affects the damping and the stiffness...... of the pipe. The behavior of the system in response to lateral resonant base excitation is analysed numerically and by the use of a perturbation method (multiple scales). Exciting the pipe in the fundamental mode of vibration seems to be most effective for transferring energy from the shaker to the fluid......, whereas higher modes of vibration can be used to transport fluid with pipe vibrations of smaller amplitude. The effect of the nonlinear geometrical terms is analysed and these terms are shown to affect the response for higher modes of vibration. Experimental investigations show good agreement...

  17. Amniotic fluid stem cells morph into a cardiovascular lineage: analysis of a chemically induced cardiac and vascular commitment.

    Science.gov (United States)

    Maioli, Margherita; Contini, Giovanni; Santaniello, Sara; Bandiera, Pasquale; Pigliaru, Gianfranco; Sanna, Raimonda; Rinaldi, Salvatore; Delitala, Alessandro P; Montella, Andrea; Bagella, Luigi; Ventura, Carlo

    2013-01-01

    Mouse embryonic stem cells were previously observed along with mesenchymal stem cells from different sources, after being treated with a mixed ester of hyaluronan with butyric and retinoic acids, to show a significant increase in the yield of cardiogenic and vascular differentiated elements. The aim of the present study was to determine if stem cells derived from primitive fetal cells present in human amniotic fluid (hAFSCs) and cultured in the presence of a mixture of hyaluronic (HA), butyric (BU), and retinoic (RA) acids show a higher yield of differentiation toward the cardiovascular phenotype as compared with untreated cells. During the differentiation process elicited by exposure to HA + BU + RA, genes controlling pluripotency and plasticity of stem cells, such as Sox2, Nanog, and Oct4, were significantly downregulated at the transcriptional level. At this point, a significant increase in expression of genes controlling the appearance of cardiogenic and vascular lineages in HA + BU + RA-treated cells was observed. The protein expression levels typical of cardiac and vascular phenotypes, evaluated by Western blotting, immunofluorescence, and flow cytometry, were higher in hAFSCs cultured in the presence of HA + BU + RA, as compared with untreated control cells. Appearance of the cardiac phenotype was further inferred by ultrastructural analysis using transmission and scanning electron microscopy. These results demonstrate that a mixture of HA + BU + RA significantly increased the yield of elements committed toward cardiac and vascular phenotypes, confirming what we have previously observed in other cellular types.

  18. Unsteady fluid and heat flow induced by a submerged stretching surface while its steady motion is slowed down gradually

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.E. [King Saud University, Riyadh (Saudi Arabia). Mechanical Engineering Department; Magyari, E. [Institute of Building Technology, ETH Zuerich (Switzerland)

    2007-01-15

    The title problem arises in the terminal stage of a large class of industrial manufacturing processes as polymer extrusion, wire drawing, drawing of plastic sheets, etc. It concerns the transient crossover to the state of rest of the fluid and heat flow which accompanies the steady fabrication process, when the devices are switched off gradually (i.e. when the motion is slowed down and the surface temperature approaches the ambient temperature continuously). The mechanical and thermal characteristics of such an unsteady process are investigated in the boundary layer approximation, assuming a linear variation of the steady stretching velocity with the longitudinal coordinate x and an inverse linear law for its decrease with time during the gradual switch-off process. For the corresponding surface temperature a general power-law variation is admitted. The paper presents the similarity analysis of several specific cases. The cases of basic interest of a constant surface temperature T{sub w} and of a constant surface heat flux q{sub w} are discussed in some detail. In the case T{sub w}=const. an exact solution is reported and the Prandtl number dependence of the corresponding surface heat flux is given for all 0

  19. Simple evaluations of fluid-induced vibrations for steam generator tube arrays in advanced marine reactors (MRX, DRX)

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuo [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan); Ishida, Toshihisa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-06-01

    Advanced Marine Reactor (MRX) and Deep Sea Research Reactor (DRX) are the integral-type PWR, and the steam generators are installed in the reactor vessels. Steam generators are of the once-through, helical-coil tube types. Heat transfer tubes surround inner shroud in annular space of the reactor vessel. Flow-induced vibrations are calculated by simple methods, and the arrangement of tube support structures are evaluated. (author)

  20. Flow of polymer fluids through porous media

    OpenAIRE

    Zami-Pierre, Frédéric; Davit, Yohan; Loubens, Romain de; Quintard, Michel

    2016-01-01

    Non-Newtonian fluids are extensively used in enhanced oil recovery. However, understanding the flow of such fluids in complex porous media remains a challenging problem. In the presented study, we use computational fluid dynamics to investigate the creeping flow of a particular non-Newtonian fluid through porous media, namely a power-law fluid with a newtonian behavior below a critical shear rate. We show that the nonlinear effects induced by the rheology only weakly impact the topological st...

  1. Noncommutative Fluid and Cosmological Perturbations

    CERN Document Server

    Das, Praloy

    2016-01-01

    In the present paper we have developed a Non-Commutative (NC) generalization of perfect fluid model from first principles, in a Hamiltonian framework. The noncommutativity is introduced at the Lagrangian (particle) coordinate space brackets and the induced NC fluid bracket algebra for the Eulerian (fluid) field variables is derived. Together with a Hamiltonian this NC algebra generates the generalized fluid dynamics that satisfies exact local conservation laws for mass and energy thereby maintaining mass and energy conservation. However, nontrivial NC correction terms appear in charge and energy fluxes. Other non-relativistic spacetime symmetries of the NC fluid are also discussed in detail. This constitutes the NC fluid dynamics and kinematics. In the second part we construct an extension of Friedmann-Robertson-Walker (FRW) cosmological model based on the NC fluid dynamics presented here. We outline the way in which NC effects generate cosmological perturbations bringing in anisotropy and inhomogeneity in th...

  2. Active colloids in complex fluids

    CERN Document Server

    Patteson, Alison E; Arratia, Paulo E

    2016-01-01

    We review recent work on active colloids or swimmers, such as self-propelled microorganisms, phoretic colloidal particles, and artificial micro-robotic systems, moving in fluid-like environments. These environments can be water-like and Newtonian but can frequently contain macromolecules, flexible polymers, soft cells, or hard particles, which impart complex, nonlinear rheological features to the fluid. While significant progress has been made on understanding how active colloids move and interact in Newtonian fluids, little is known on how active colloids behave in complex and non-Newtonian fluids. An emerging literature is starting to show how fluid rheology can dramatically change the gaits and speeds of individual swimmers. Simultaneously, a moving swimmer induces time dependent, three dimensional fluid flows, that can modify the medium (fluid) rheological properties. This two-way, non-linear coupling at microscopic scales has profound implications at meso- and macro-scales: steady state suspension proper...

  3. Fluid Dynamics

    DEFF Research Database (Denmark)

    Brorsen, Michael

    These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....

  4. Aerosolized STAT1 Antisense Oligodeoxynucleotides Decrease the Concentrations of Inflammatory Mediators in Bronchoalveolar Lavage Fluid in Bleomycin-Induced Rat Pulmonary Fibrosis

    Institute of Scientific and Technical Information of China (English)

    Ming Zeng; Bin Liao; Chen Zhu; Wenjun Wang; Xiaoqin Zhan; Xianming Fan

    2008-01-01

    It has been demonstrated that alveolar macrophages (AMs) play a key role in the pathogenesis of pulmonary fibrosis by releasing a variety of cytokines and inflammatory mediators. In addition, abnormal signal transducer and activator of transcription-1 (STAT1) activation in AMs may play a pivotal role in the process of alveolitis and pulmonary fibrosis. In this study, we transfected STAT1 antisense oligodeoxynucleotide (ASON) into rats by aerosolization, and then investigated the effect of STAT1 ASON on inflammatory mediators such as TGF-β, PDGF and TNF-α in bronchoalveolar lavage fluid (BALF) from rats with bleomycin (BLM)-induced rat pulmonary fibrosis. Our results showed that STAT1 ASON by aerosolization could enter into lung tissues and AMs. STAT1 ASON could inhibit mRNA and protein expressions of STATI and ICAM-1 in AMs of rat with pulmonary fibrosis, and had no toxic side effect on liver and kidney. Aerosolized STAT1 ASON could ameliorate the alveolitis through inhibiting the secretion of inflammatory mediators in BLM-induced rat pulmonary fibrosis. These results suggest that aerosolized STAT1 ASON might be considered as a promising new strategy in the treatment of pulmonary fibrosis. Cellular & Molecular Immunology. 2008;5(3):219-224.

  5. Contribution of CFTR to Alveolar Fluid Clearance by Lipoxin A4 via PI3K/Akt Pathway in LPS-Induced Acute Lung Injury

    Directory of Open Access Journals (Sweden)

    Yi Yang

    2013-01-01

    Full Text Available The lipoxins are the first proresolution mediators to be recognized and described as the endogenous “braking signals” for inflammation. We evaluated the anti-inflammatory and proresolution bioactions of lipoxin A4 in our lipopolysaccharide (LPS-induced lung injury model. We demonstrated that lipoxin A4 significantly improved histology of rat lungs and inhibited IL-6 and TNF-α in LPS-induced lung injury. In addition, lipoxin A4 increased alveolar fluid clearance (AFC and the effect of lipoxin A4 on AFC was abolished by CFTRinh-172 (a specific inhibitor of CFTR. Moreover, lipoxin A4 could increase cystic fibrosis transmembrane conductance regulator (CFTR protein expression in vitro and in vivo. In rat primary alveolar type II (ATII cells, LPS decreased CFTR protein expression via activation of PI3K/Akt, and lipoxin A4 suppressed LPS-stimulated phosphorylation of Akt. These results showed that lipoxin A4 enhanced CFTR protein expression and increased AFC via PI3K/Akt pathway. Thus, lipoxin A4 may provide a potential therapeutic approach for acute lung injury.

  6. Fluid-flow-induced mesenchymal stem cell migration: role of focal adhesion kinase and RhoA kinase sensors.

    Science.gov (United States)

    Riehl, Brandon D; Lee, Jeong Soon; Ha, Ligyeom; Lim, Jung Yul

    2015-03-01

    The study of mesenchymal stem cell (MSC) migration under flow conditions with investigation of the underlying molecular mechanism could lead to a better understanding and outcome in stem-cell-based cell therapy and regenerative medicine. We used peer-reviewed open source software to develop methods for efficiently and accurately tracking, measuring and processing cell migration as well as morphology. Using these tools, we investigated MSC migration under flow-induced shear and tested the molecular mechanism with stable knockdown of focal adhesion kinase (FAK) and RhoA kinase (ROCK). Under steady flow, MSCs migrated following the flow direction in a shear stress magnitude-dependent manner, as assessed by root mean square displacement and mean square displacement, motility coefficient and confinement ratio. Silencing FAK in MSCs suppressed morphology adaptation capability and reduced cellular motility for both static and flow conditions. Interestingly, ROCK silencing significantly increased migration tendency especially under flow. Blocking ROCK, which is known to reduce cytoskeletal tension, may lower the resistance to skeletal remodelling during the flow-induced migration. Our data thus propose a potentially differential role of focal adhesion and cytoskeletal tension signalling elements in MSC migration under flow shear.

  7. Fluid-induced transition from banded kyanite- to bimineralic eclogite and implications for the evolution of cratons

    Science.gov (United States)

    Sommer, H.; Jacob, D. E.; Stern, R. A.; Petts, D.; Mattey, D. P.; Pearson, D. G.

    2017-06-01

    Heterogeneous, modally banded kyanite-bearing and bimineralic eclogites from the lithospheric mantle, collected at the Roberts Victor Diamond mine (South Africa), show a reaction texture in which kyanite is consumed. Geothermobarometric calculations using measured mineral compositions in Perple_X allowed the construction of a P-T path showing a steep, cool prograde metamorphic gradient of 2 °C/km to reach peak conditions of 5.8 GPa and 890 °C for the kyanite eclogite. The kyanite-out reaction formed bimineralic eclogite and is probably an integral part of the mineralogical evolution of most archetypal bimineralic eclogites at Roberts Victor and potentially elsewhere. The kyanite-out reaction occured at close to peak pressure (5.3 GPa) and was associated with a rise in temperature to 1380 °C. Mass balance calculations show that upon breakdown, the kyanite component is fully accommodated in garnet and omphacite via a reaction system with low water fugacity that required restricted fluid influx from metasomatic sources. The δ18O values of garnets are consistently higher than normal mantle values. Each sample has its characteristic trend of δ18O variance between garnets in the kyanite-bearing sections and those in the bimineralic parts covering a range between 5.1‰ and 6.8‰. No systematic change in O-isotope signature exists across the sample population. Differences in garnet trace element signatures between differing lithologies in the eclogites are significant. Grossular-rich garnets coexisting with kyanite have strong positive Eu-anomalies and low Gd/Yb ratios, while more pyrope-rich garnets in the bimineralic sections have lost their positive Eu-anomaly, have higher Gd/Yb ratios and generally higher heavy rare earth element contents. Garnets in the original kyanite-bearing portions thus reflect the provenance of the rocks as metamorphosed gabbros/troctolites. The kyanite-out reaction was most likely triggered by a heating event in the subcratonic

  8. Early phase components of the kallikrein kinin system in hemorrhagic ascitic fluid and plasma in the rat with induced acute pancreatitis.

    Science.gov (United States)

    Seung, W P; Feldman, B F

    1985-09-01

    Acute hemorrhagic pancreatitis (AHP) was induced in 43 anesthetized rats by retrograde injection of sodium taurodeoxycholic acid into the common pancreatic biliary duct. At postinjection hours 1, 3, 6, 12, and 18, samples of plasma and hemorrhagic ascitic fluid (HAF) were obtained from rats in which AHP was induced and from rats that were sham operated. Early phase components of the kallikrein kinin system, including kallikrein-like (KK) activity and prekallikrein (PKK) and kallikrein inhibitor (KKI) concentrations, were measured in plasma and HAF samples. In the rats with induced AHP, PKK concentrations were decreased significantly in 18-hour plasma samples (P less than 0.05) and in all HAF samples (P less than 0.001) from 1 to 18 hours after induction of AHP. The KK activity was significantly increased (P less than 0.001) in the 6- and 12-hour plasma samples. In the 1-hour HAF samples, KK activity was increased greater than 10 times over that in the plasma pool of rats and remained increased for 18 hours. The KKI concentrations were markedly decreased in all HAF samples. In the sham-operated group, no significant change was observed. Histopathologic changes included edema, extensive hemorrhage, focal necrosis of many acinar cells around the head of the pancreas, slight inflammatory cell infiltration, vascular thrombosis, and partial lysis of pancreatic ducts. The extent of the changes of PKK, KK, and KKI values in HAF was greater than the extent of those in plasma. Increasing KK activity in plasma and HAF is indicative of bradykinin generation and the participation of this system in local and systemic pathologic change.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Parathyroid hormone enhances fluid shear-induced [Ca2+]i signaling in osteoblastic cells through activation of mechanosensitive and voltage-sensitive Ca2+ channels

    Science.gov (United States)

    Ryder, K. D.; Duncan, R. L.

    2001-01-01

    Osteoblasts respond to both fluid shear and parathyroid hormone (PTH) with a rapid increase in intracellular calcium concentration ([Ca2+]i). Because both stimuli modulate the kinetics of the mechanosensitive cation channel (MSCC), we postulated PTH would enhance the [Ca2+]i response to fluid shear by increasing the sensitivity of MSCCs. After a 3-minute preflow at 1 dyne/cm2, MC3T3-E1 cells were subjected to various levels of shear and changes in [Ca2+]i were assessed using Fura-2. Pretreatment with 50 nM bovine PTH(1-34) [bPTH(1-34)] significantly enhanced the shear magnitude-dependent increase in [Ca2+]i. Gadolinium (Gd3+), an MSCC blocker, significantly inhibited the mean peak [Ca2+]i response to shear and shear + bPTH(1-34). Nifedipine (Nif), an L-type voltage-sensitive Ca2+ channel (VSCC) blocker, also significantly reduced the [Ca2+]i response to shear + bPTH(1-34), but not to shear alone, suggesting VSCC activation plays an interactive role in the action of these stimuli together. Activation of either the protein kinase C (PKC) or protein kinase A (PKA) pathways with specific agonists indicated that PKC activation did not alter the Ca2+ response to shear, whereas PKA activation significantly increased the [Ca2+]i response to lower magnitudes of shear. bPTH(1-34), which activates both pathways, induced the greatest [Ca2+]i response at each level of shear, suggesting an interaction of these pathways in this response. These data indicate that PTH significantly enhances the [Ca2+]i response to shear primarily via PKA modulation of the MSCC and VSCC.

  10. Added mass induced by an uncompressible ideal and still fluid on a structure a bibliography; Prise en compte d`un fluide parfait incompressible au repos comme masse ajoutee sur une structure. Synthese bibliographique

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, G.

    1994-02-01

    We first recall the most important definitions about the fluid/structure interaction. We also define some non-dimensional numbers in order to analyze the physical effects in the fluid we have to take into account: viscosity, compressibility, gravity, inertial effect. Then, in the first part called ``Calculation of the added mass: Models``, we explain the equations which allow us to find the added mass on one structure. After that, we deal with the dynamical behaviour of tube bundles immersed in a fluid. We present a two dimensional modelling. Therefore, the fluid structure interaction only takes place in the planes perpendicular to the tube axis. The added mass matrix of the fluid on the whole tubes is built for every kind of cross-section. But we also focus our attention on the special case of circular cross-section. Lastly, when the number of the tubes in the bundle is huge, the direct calculation of the global added mass matrix is impossible: we must use a method of homogenization to describe the global dynamical behaviour of the tube bundles. In particular, the eigenfrequencies of such homogenized medium are determined. We especially focus our attention on the square nuclear fuel bundles immersed in a confined fluid. In the second part called ``Numerical methods used for the fluid structure interaction``, we first tackle the integral methods. However, in these methods, some theoretical and numerical difficulties arise and this fact makes the advantage of a little number of degrees of freedom far less interesting. This leads us to consider the finite element methods. It allows us to determine the added mass matrix of the fluid on the structure expressed with the nodal interpolation functions used by the FE methods. We then propose a discretization of the equations of the movement of tube bundles immersed in a fluid, with or without homogenization. At last, we compare the efficiency of the integral methods to the FE methods. (author). figs., tabs., 54 refs.

  11. Cerebrospinal fluid levels of catecholamine metabolites in Parkinson’s disease and L-DOPA-induced dyskinesia

    DEFF Research Database (Denmark)

    Dammann Andersen, Andreas; Binzer, Michael; Stenager, Egon;

    Levodopa (L-DOPA) is effective in the symptomatic treatment of Parkinson’s disease (PD), but chronic use is associated with L-DOPA-induced dyskinesia (LID). In the 6-hydroxydopamine rat model of PD, L-DOPA treatment increases dopamine, its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC...... fasting and 1 hour after intake of medication. Results and conclusion: PD patients receiving levodopa had 10-20 fold higher L-DOPA levels and about 100 fold higher levels of 3-OMD than age-matched controls or PD not receiving L-DOPA. DOPAC levels were not different among controls and subgroups of PD. HVA...... levels were significantly lower in non-DOPA-treated PD. Ratios of DOPAC/DOPA or HVA/DOPA were much lower in levodopa-treated patients, not distinguishing dyskinetic (N=6) from non-dyskinetic PD patients (N=5). More patients need to be included. Tryptophan/kynurenine metabolites will be analysed using LC...

  12. Fluid dynamics of dilatant fluid

    DEFF Research Database (Denmark)

    Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko

    2012-01-01

    A dense mixture of granules and liquid often shows a severe shear thickening and is called a dilatant fluid. We construct a fluid dynamics model for the dilatant fluid by introducing a phenomenological state variable for a local state of dispersed particles. With simple assumptions for an equation...... of the state variable, we demonstrate that the model can describe basic features of the dilatant fluid such as the stress-shear rate curve that represents discontinuous severe shear thickening, hysteresis upon changing shear rate, and instantaneous hardening upon external impact. An analysis of the model...... reveals that the shear thickening fluid shows an instability in a shear flow for some regime and exhibits the shear thickening oscillation (i.e., the oscillatory shear flow alternating between the thickened and the relaxed states). The results of numerical simulations are presented for one- and two...

  13. Fluid dynamics

    CERN Document Server

    Bernard, Peter S

    2015-01-01

    This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.

  14. Numerical Investigation on Stress Shadowing in Fluid Injection-Induced Fracture Propagation in Naturally Fractured Geothermal Reservoirs

    Science.gov (United States)

    Yoon, Jeoung Seok; Zimmermann, Günter; Zang, Arno

    2015-07-01

    In low permeability shale reservoirs, multi-stage hydraulic fracturing is largely used to increase the productivity by enlarging the stimulated rock volume. Hydraulic fracture created alters the stress field around it, and affects the subsequent fractures by the change of the stress field, in particular, mostly increased minimum principal stress at the area of subsequent fracturing. This is called stress shadow which accumulates as the fracturing stages advance from toe to heel. Hydraulic fractures generated in such altered stress field are shorter and compact with orientation deviating significantly from the far-field maximum horizontal stress orientation. This paper presents 2D discrete element-based numerical modeling of multi-stage hydraulic fracturing in a naturally fractured reservoir and investigates stress shadowing. The stress shadowing is tested with two different injection scenarios: constant and cyclic rate injections. The results show that cyclic injection tends to lower the effect of stress shadow as well as mitigates the magnitude of the induced seismicity. Another modeling case is presented to show how the stress shadow can be utilized to optimize a hydraulic fracture network in application to Groß Schönebeck geothermal reservoir, rather than being mitigated. The modeling demonstrated that the stress shadow is successfully utilized for optimizing the geothermal heat exchanger by altering the initial in situ stress field from highly anisotropic to less or even to isotropic.

  15. Mechanics of fluid flow

    CERN Document Server

    Basniev, Kaplan S; Chilingar, George V 0

    2012-01-01

    The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry.  This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike.  It is a must-have for any engineer working in the oil and gas industry.

  16. Duration of exposure to high fluid shear stress is critical in shear-induced platelet activation-aggregation.

    Science.gov (United States)

    Zhang, Jian-ning; Bergeron, Angela L; Yu, Qinghua; Sun, Carol; McBride, Latresha; Bray, Paul F; Dong, Jing-fei

    2003-10-01

    Platelet functions are increasingly measured under flow conditions to account for blood hydrodynamic effects. Typically, these studies involve exposing platelets to high shear stress for periods significantly longer than would occur in vivo. In the current study, we demonstrate that the platelet response to high shear depends on the duration of shear exposure. In response to a 100 dyn/cm2 shear stress for periods less than 10-20 sec, platelets in PRP or washed platelets were aggregated, but minimally activated as demonstrated by P-selectin expression and binding of the activation-dependent alphaIIbbeta3 antibody PAC-1 to sheared platelets. Furthermore, platelet aggregation under such short pulses of high shear was subjected to rapid disaggregation. The disaggregated platelets could be re-aggregated by ADP in a pattern similar to unsheared platelets. In comparison, platelets that are exposed to high shear for longer than 20 sec are activated and aggregated irreversibly. In contrast, platelet activation and aggregation were significantly greater in whole blood with significantly less disaggregation. The enhancement is likely via increased collision frequency of platelet-platelet interaction and duration of platelet-platelet association due to high cell density. It may also be attributed to the ADP release from other cells such as red blood cells because increased platelet aggregation in whole blood was partially inhibited by ADP blockage. These studies demonstrate that platelets have a higher threshold for shear stress than previously believed. In a pathologically relevant timeframe, high shear alone is likely to be insufficient in inducing platelet activation and aggregation, but acts synergistically with other stimuli.

  17. Development of post-traumatic epilepsy after controlled cortical impact and lateral fluid-percussion-induced brain injury in the mouse.

    Science.gov (United States)

    Bolkvadze, Tamuna; Pitkänen, Asla

    2012-03-20

    The present study investigated the development of hyperexcitability and epilepsy in mice with traumatic brain injury (TBI) induced by controlled cortical impact (CCI) or lateral fluid-percussion injury (FPI), which are the two most commonly used experimental models of human TBI in rodents. TBI was induced with CCI to 50 (14 controls) and with lateral FPI to 45 (15 controls) C57BL/6S adult male mice. The animals were followed-up for 9 months, including three 2-week periods of continuous video-electroencephalographic (EEG) monitoring, and a seizure susceptibility test with pentylenetetrazol (PTZ). In the end, the animals were perfusion-fixed for histology. The experiment included two independent cohorts of animals. Late post-traumatic spontaneous electrographic seizures were detected in 9% of mice after CCI and 3% after lateral FPI. Eighty-two percent of mice after CCI and 71% after lateral FPI had spontaneous epileptiform spiking on EEG. In addition, 58% of mice with lateral FPI showed spontaneous epileptiform discharges. A PTZ test demonstrated increased seizure susceptibility in the majority of mice in both models, compared to control mice. There was no further progression in the occurrence of epilepsy or epileptiform spiking when follow-up was extended from 6 to 9 months. The severity of cortical or hippocampal damage did not differentiate mice with or without epileptiform activity in either model. Finally, two independent series of experiments in both injury models provided comparable data demonstrating reproducibility of the modeling. These data show that different types of impact can trigger epileptogenesis in mice. Even though the frequency of spontaneous seizures in C57BL/6S mice is low, a large majority of animals develop hyperexcitability.

  18. Prevention of Contrast-Induced Nephropathy by Central Venous Pressure-Guided Fluid Administration in Chronic Kidney Disease and Congestive Heart Failure Patients.

    Science.gov (United States)

    Qian, Geng; Fu, Zhenhong; Guo, Jun; Cao, Feng; Chen, Yundai

    2016-01-11

    This study aimed to explore the hemodynamic index-guided hydration method for patients with congestive heart failure (CHF) and chronic kidney disease (CKD) to reduce the risk of contrast-induced nephropathy (CIN) and at the same time to avoid the acute heart failure. Patients at moderate or high risk for CIN should receive sufficient hydration before contrast application. This prospective, randomized, double-blind, comparative clinical trial enrolled 264 consecutive patients with CKD and CHF undergoing coronary procedures. These patients were randomly assigned to either central venous pressure (CVP)-guided hydration group (n = 132) or the standard hydration group (n = 132). In the CVP-guided group, the hydration infusion rate was dynamically adjusted according to CVP level every hour. CIN was defined as an absolute increase in serum creatinine (SCr) >0.5 mg/dl (44.2 μmol/l) or a relative increase >25% compared with baseline SCr. Baseline characteristics were well-matched between the 2 groups. The total mean volume of isotonic saline administered in the CVP-guided hydration group was significantly higher than the control group (1,827 ± 497 ml vs. 1,202 ± 247 ml; p heart failure during the hydration did not differ between the 2 groups (3.8% vs. 3.0%; p = 0.500). CVP-guided fluid administration can safely and effectively reduce the risk of CIN in patients with CKD and CHF. (Central Venous Pressure Guided Hydration Prevention for Contrast-Induced Nephropathy; NCT02405377). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  19. Cigarette smoking induced liver insult concomitant with inflammatory mediators in serum crevicular fluid and bronchio alveolar lavage of schistosomal diabetic subjects with history of bronchial asthma.

    Science.gov (United States)

    El-Dardiry, Samia A; Shafik, Sherine R; Wagih, Ayman; Amir, El-Amir M; Kassem, Gamal K; Atef, Ghada; El-Toukhy, Heba

    2007-08-01

    Forty five smokers were classified into schistosomal cases with type-2 diabetis mellitus (GI) and with associated history of bronchial asthma (GII) and without T-2 DM (GIII). A control group (GIV) of non-diabetic non schistosomal age matched subjects who quitted smoking for >6 months were included. Assessed parameters included indices of glycemic status (glycated hemoglobin), angiogenesis (vascular endothelial growth factor) hepatic and bronchoalveolar disposition (Liver function test, metallothionein, serum levels of cotinine, cadmium selenium, copper & zinc) and bronchoalveolar lavage) (BAL) levels of surfactant proteins A & D, zinc and copper oxidative stress and fibrogenesis (total antioxidant capacity thiobarbituric acid reactive substance) and vasculopathy (angiotensin converting enzyme, P-selectin, nitrate) and periodontitis (collagenase and elastase in GCF) impact of cigarette smoking associated with trace element disbalance and enzymatic changes in crevicular fluid on altered parameters collaborative out-come. The study reflected the collaborative outcome of immune mediated mechanisms initiated by liver affection, glycemic status and history of predisposed bronchial integrity induced by oxidative stress.

  20. Glial cell line-derived neurotrophic factor induced the differentiation of amniotic fluid-derived stem cells into vascular endothelial-like cells in vitro.

    Science.gov (United States)

    Zhang, Ruyu; Lu, Ying; Li, Ju; Wang, Jia; Liu, Caixia; Gao, Fang; Sun, Dong

    2016-02-01

    Amniotic fluid-derived stem cells (AFSCs) are a novel source of stem cells that are isolated and cultured from second trimester amniocentesis. Glial cell line-derived neurotrophic factor (GDNF) acts as a tissue morphogen and regulates stem cell proliferation and differentiation. This study investigated the effect of an adenovirus-mediated GDNF gene, which was engineered into AFSCs, on the cells' biological properties and whether GDNF in combination with AFSCs can be directionally differentiated into vascular endothelial-like cells in vitro. AFSCs were isolated and cultured using the plastic adherence method in vitro and identified by the transcription factor Oct-4, which is the primary marker of pluripotent stem cells. AFSCs were efficiently transfected by a GFP-labeled plasmid system of an adenovirus vector carrying the GDNF gene (Ad-GDNF-GFP). Transfected AFSCs stably expressed GDNF. Transfected AFSCs were cultured in endothelial growth medium-2 containing vascular endothelial growth factor. After 1 week, AFSCs were positive for von Willebrand factor (vWF) and CD31, which are markers of endothelial cells, and the recombinant GDNF group was significantly higher than undifferentiated controls and the GFP only group. These results demonstrated that AFSCs differentiated into vascular endothelial-like cells in vitro, and recombinant GDNF promoted differentiation. The differentiation-induced AFSCs may be used as seed cells to provide a new manner of cell and gene therapies for transplantation into the vascular injury site to promote angiogenesis.

  1. BACE1 inhibition induces a specific cerebrospinal fluid β-amyloid pattern that identifies drug effects in the central nervous system.

    Directory of Open Access Journals (Sweden)

    Niklas Mattsson

    Full Text Available BACE1 is a key enzyme for amyloid-β (Aβ production, and an attractive therapeutic target in Alzheimer's disease (AD. Here we report that BACE1 inhibitors have distinct effects on neuronal Aβ metabolism, inducing a unique pattern of secreted Aβ peptides, analyzed in cell media from amyloid precursor protein (APP transfected cells and in cerebrospinal fluid (CSF from dogs by immunoprecipitation-mass spectrometry, using several different BACE1 inhibitors. Besides the expected reductions in Aβ1-40 and Aβ1-42, treatment also changed the relative levels of several other Aβ isoforms. In particular Aβ1-34 decreased, while Aβ5-40 increased, and these changes were more sensitive to BACE1 inhibition than the changes in Aβ1-40 and Aβ1-42. The effects on Aβ5-40 indicate the presence of a BACE1 independent pathway of APP degradation. The described CSF Aβ pattern may be used as a pharmacodynamic fingerprint to detect biochemical effects of BACE1-therapies in clinical trials, which might accelerate development of novel therapies.

  2. R fluids

    Directory of Open Access Journals (Sweden)

    Caimmi R.

    2008-01-01

    Full Text Available A theory of collisionless fluids is developed in a unified picture, where nonrotating (Ωf1 = Ωf2 = Ωf3 = 0 figures with some given random velocity component distributions, and rotating (Ωf1 = Ωf2 = Ωf3 figures with a different random velocity component distributions, make adjoint configurations to the same system. R fluids are defined as ideal, self-gravitating fluids satisfying the virial theorem assumptions, in presence of systematic rotation around each of the principal axes of inertia. To this aim, mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The figure rotation is defined as the mean angular velocity, weighted on the moment of inertia, with respect to a selected axis. The generalized tensor virial equations (Caimmi and Marmo 2005 are formulated for R fluids and further attention is devoted to axisymmetric configurations where, for selected coordinate axes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and vice versa. A microscopical analysis of systematic and random motions is performed under a few general hypotheses, by reversing the sign of tangential or axial velocity components of an assigned fraction of particles, leaving the distribution function and other parameters unchanged (Meza 2002. The application of the reversion process to tangential velocity components is found to imply the conversion of random motion rotation kinetic energy into systematic motion rotation kinetic energy. The application of the reversion process to axial velocity components is found to imply the conversion of random motion translation kinetic energy into systematic motion translation kinetic energy, and the loss related to a change of reference frame is expressed in terms of systematic motion (imaginary rotation kinetic energy. A number of special situations are investigated in greater

  3. Gravity Probe-B Spacecraft attitude control based on the dynamics of slosh wave-induced fluid stress distribution on rotating dewar container of cryogenic propellant

    Science.gov (United States)

    Hung, R. J.; Lee, C. C.; Leslie, F. W.

    1991-01-01

    The dynamical behavior of fluids, in particular the effect of surface tension on partially-filled rotating fluids, in a full-scale Gravity Probe-B Spacecraft propellant dewar tank imposed by various frequencies of gravity jitters have been investigated. Results show that fluid stress distribution exerted on the outer and inner walls of rotating dewar are closely related to the characteristics of slosh waves excited on the liquid-vapor interface in the rotating dewar tank. This can provide a set of tool for the spacecraft dynamic control leading toward the control of spacecraft unbalance caused by the uneven fluid stress distribution due to slosh wave excitations.

  4. R Fluids

    Directory of Open Access Journals (Sweden)

    Caimmi, R.

    2008-06-01

    Full Text Available A theory of collisionless fluids is developed in a unified picture, where nonrotating $(widetilde{Omega_1}=widetilde{Omega_2}= widetilde{Omega_3}=0$ figures with some given random velocity component distributions, and rotating $(widetilde{Omega_1} ewidetilde{Omega_2} e widetilde{Omega_3} $ figures with a different random velocity component distributions, make adjoint configurations to the same system. R fluids are defined as ideal, self-gravitating fluids satisfying the virial theorem assumptions, in presence of systematic rotation around each of the principal axes of inertia. To this aim, mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The figure rotation is defined as the mean angular velocity, weighted on the moment of inertia, with respectto a selected axis. The generalized tensor virial equations (Caimmi and Marmo 2005 are formulated for R fluidsand further attention is devoted to axisymmetric configurations where, for selected coordinateaxes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and viceversa. A microscopical analysis of systematic and random motions is performed under a fewgeneral hypotheses, by reversing the sign of tangential or axial velocity components of anassigned fraction of particles, leaving the distribution function and other parametersunchanged (Meza 2002. The application of the reversion process to tangential velocitycomponents is found to imply the conversion of random motion rotation kinetic energy intosystematic motion rotation kinetic energy. The application ofthe reversion process to axial velocity components is found to imply the conversionof random motion translation kinetic energy into systematic motion translation kinetic energy, and theloss related to a change of reference frame is expressed in terms of systematic motion (imaginary rotation kinetic

  5. Proteomic kinetic analysis of blister fluid and serum in a patient with drug-induced toxic epidermal necrolysis. A comparison with skin immunohistochemistry.

    Science.gov (United States)

    Paquet, Philippe; Meuwis, Marie-Alice; Mazzucchelli, Gabriel; Delvenne, Philippe; Piérard, Gerald E

    2012-11-01

    Drug-induced toxic epidermal necrolysis (TEN) is a rare but potentially lethal bullous disease whose complex pathomechanisms remain uncertain. The aim of the study was an exploratory attempt to assess TEN pathobiology using a combination of immunohistochemistry and proteomics. Skin blister fluid (BF) and serum were collected in a patient in the early TEN stage at day (D) +4 of evolution and three days later (D +7). Intravenous cyclosporine A (CsA) treatment was initiated since D +4. Immunohistochemistry was performed on skin blister biopsies. In addition, proteomic analyses compared the BF protein content before and at the issue of the 3-day CsA treatment. Proteins were selected according to their prominent differential abundance in BF between D+4 and D+7, when influenced by lesional skin cells, but not in serum. Among 300 proteins, four were considered. Glutathione transferase π was related to oxidative stress in TEN epidermis. The monocyte differentiation antigen CD14 and myeloperoxidase indicated macrophage activation. The proinflammatory S100-A8 protein probably originated from activated keratinocytes and/or macrophages. These proteomic findings were in line with immunohistochemistry and supported the prominent involvement of keratinocytes and macrophages in TEN pathomechanism. As opposed to CD14, other proteins were mainly present in BF at D+7, confirming that CsA expressed little effect, if any, on the activity of keratinocytes and macrophages in the present TEN patient. Of note, the present exploratory study using proteomic analyses in a single TEN case supports a pathogenic hypothesis without establishing any firm conclusion.

  6. N-Acetyl-Cysteine and l-Carnitine Prevent Meiotic Oocyte Damage Induced by Follicular Fluid From Infertile Women With Mild Endometriosis.

    Science.gov (United States)

    Giorgi, Vanessa S I; Da Broi, Michele G; Paz, Claudia C P; Ferriani, Rui A; Navarro, Paula A

    2016-03-01

    This study evaluated the potential protective effect of the antioxidants, l-carnitine (LC) and N-acetyl-cysteine (NAC), in preventing meiotic oocyte damage induced by follicular fluid (FF) from infertile women with mild endometriosis (ME). We performed an experimental study. The FF samples were obtained from 22 infertile women undergoing stimulated cycles for intracytoplasmic sperm injection (11 with ME and 11 without endometriosis). Immature bovine oocytes were submitted to in vitro maturation (IVM) divided into 9 groups: no-FF (No-FF); with FF from control (CFF) or ME (EFF) groups; and with LC (C + LC and E + LC), NAC (C + NAC and E + NAC), or both antioxidants (C + 2Ao and E + 2Ao). After IVM, oocytes were immunostained for visualization of microtubules and chromatin by confocal microscopy. The percentage of meiotically normal metaphase II (MII) oocytes was significantly lower in the EFF group (51.35%) compared to No-FF (86.36%) and CFF (83.52%) groups. The E + NAC (62.22%), E + LC (80.61%), and E + 2Ao (61.40%) groups showed higher percentage of normal MII than EFF group. The E + LC group showed higher percentage of normal MII than E + NAC and E + 2Ao groups and a similar percentage to No-FF and CFF groups. Therefore, FF from infertile women with ME causes meiotic abnormalities in bovine oocytes, and, for the first time, we demonstrated that the use of NAC and LC prevents these damages. Our findings elucidate part of the pathogenic mechanisms involved in infertility associated with ME and open perspectives for further studies investigating whether the use of LC could improve the natural fertility and/or the results of in vitro fertilization of women with ME.

  7. IgA Complexes in Plasma and Synovial Fluid of Patients with Rheumatoid Arthritis Induce Neutrophil Extracellular Traps via FcαRI.

    Science.gov (United States)

    Aleyd, Esil; Al, Marjon; Tuk, Cornelis W; van der Laken, Conny J; van Egmond, Marjolein

    2016-12-15

    Autoantibodies, including rheumatoid factor (RF), are an important characteristic of rheumatoid arthritis (RA). Interestingly, several studies reported a correlation between the presence of IgA autoantibodies and worse disease course. We demonstrated previously that triggering the IgA Fc receptor (FcαRI) on neutrophils results in neutrophil recruitment and the release of neutrophil extracellular traps (NETs). Because this can lead to tissue damage, we investigated whether IgA immune complexes in plasma and synovial fluid of RA patients activate neutrophils. RF isotypes were measured with ELISA, and immune complexes were precipitated using polyethylene glycol 6000. Isolated neutrophils were incubated with immune complexes, and activation and release of NETs were determined in the presence or absence of FcαRI-blocking Abs. Plasma and SF of RA patients contained IgM, IgG, and IgA RFs. Patient plasma IgA RF and IgM RF showed a strong correlation. No uptake of IgM and minimal endocytosis of IgG immune complexes by neutrophils was observed, in contrast to avid uptake of IgA complexes. Incubation of neutrophils with immune complexes resulted in the production of reactive oxygen species, as well as the release of NETs, lactoferrin, and chemotactic stimuli. Importantly, activation of neutrophils was reduced when FcαRI was blocked. Neutrophils were activated by IgA immune complexes, which suggests that neutrophils play a role in inducing joint damage in RA patients who have IgA autoantibody complexes, thereby increasing the severity of disease. Blocking FcαRI inhibited neutrophil activation and, as such, may represent an additional attractive novel therapeutic strategy for the treatment of RA.

  8. Comparison of PUFA profiles in the blood and in follicular fluid and its association with follicular dynamics after PGF2α induced luteolysis in dairy cows

    Directory of Open Access Journals (Sweden)

    Branko Atanasov

    2016-10-01

    Full Text Available The objectives of the present study were to examine the fatty acid (FA profiles in serum and in the follicular fluid (FF and the association between polyunsaturated fatty acid level (PUFA and follicular growth dynamics following induced luteolysis in dairy cows. A total of 29 dairy cows (CL>25mm, follicle≈15mm at d0 (start of the experiment were submitted to ultrasound guided transvaginal follicular aspiration for FF collection from the largest follicle and were injected with 500 μg of cloprostenol. The cows were subdivided into Group A1 (n=11 and Group A2 (n=8 resuming follicular growth either from a secondary follicle less than or larger than 8.5mm, respectively, present at the moment of aspiration and Group A0 (n=10 not resuming follicular growth. Follicular development was monitored daily by ultrasonography until the next dominant follicle reached ≈15mm and was subsequently punctured in Group A1 and A2 (d1. Serum and FF samples for FA determination were taken at d0 from all cows and at d1 in Group A1 and A2. No differences were observed between the FA profile in serum nor in FF between sampling days. Regarding the PUFA levels, the serum linoleic acid (C18:2n6 levels at d0 and d1 were significantly higher than in FF, while alpha linolenic acid (C18:3n3 was lower in the serum than in FF, both at d0 and d1. At d0, a tendency for negative correlation between serum and the FF C18:2n6 with subsequent daily follicular growth rate was observed, while, at d1 there was a strong negative correlation between the serum C18:2n6 and daily growth rate (r=-0.71; p=0.0006. The present study revealed similarities of the FA profiles in the serum and in the FF and association between serum and FF PUFA content with the follicular dynamics after induced luteolysis.

  9. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  10. Analytical solutions for wall slip effects on magnetohydrodynamic oscillatory rotating plate and channel flows in porous media using a fractional Burgers viscoelastic model

    Science.gov (United States)

    Maqbool, Khadija; Anwar Bég, O.; Sohail, Ayesha; Idreesa, Shafaq

    2016-05-01

    The theoretical analysis of magnetohydrodynamic (MHD) incompressible flows of a Burgers fluid through a porous medium in a rotating frame of reference is presented. The constitutive model of a Burgers fluid is used based on a fractional calculus formulation. Hydrodynamic slip at the wall (plate) is incorporated and the fractional generalized Darcy model deployed to simulate porous medium drag force effects. Three different cases are considered: namely, the flow induced by a general periodic oscillation at a rigid plate, the periodic flow in a parallel plate channel and, finally, the Poiseuille flow. In all cases the plate(s) boundary(ies) are electrically non-conducting and a small magnetic Reynolds number is assumed, negating magnetic induction effects. The well-posed boundary value problems associated with each case are solved via Fourier transforms. Comparisons are made between the results derived with and without slip conditions. Four special cases are retrieved from the general fractional Burgers model, viz. Newtonian fluid, general Maxwell viscoelastic fluid, generalized Oldroyd-B fluid and the conventional Burgers viscoelastic model. Extensive interpretation of graphical plots is included. We study explicitly the influence of the wall slip on primary and secondary velocity evolution. The model is relevant to MHD rotating energy generators employing rheological working fluids.

  11. Pleural Fluid Analysis Test

    Science.gov (United States)

    ... Home Visit Global Sites Search Help? Pleural Fluid Analysis Share this page: Was this page helpful? Formal name: Pleural Fluid Analysis Related tests: Pericardial Fluid Analysis , Peritoneal Fluid Analysis , ...

  12. Electrorheologic fluids; Fluidos electroreologicos

    Energy Technology Data Exchange (ETDEWEB)

    Rejon G, Leonardo; Lopez G, Francisco; Montoya T, Gerardo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Manero B, Octavio [Instituto de Investigaciones en Materiales, UNAM.(Mexico)

    2003-07-01

    The present article has as an objective to offer a review of the research work made in the Instituto de Investigaciones Electricas (IIE) on the study of the electrorheologic fluids whose flow properties can abruptly change in the presence of an electric field when this is induced by a direct current. The electrorheologic fluids have their main application in the manufacture of self-controlling damping systems. [Spanish] El presente articulo tiene por objetivo ofrecer una resena de los trabajos de investigacion realizados en el Instituto de Investigaciones Electricas (IIE) sobre el estudio de los fluidos electroreologicos cuyas propiedades de flujo pueden cambiar abruptamente en presencia de un campo electrico cuando este es inducido por una corriente directa. Los fluidos electroreologicos tienen su principal aplicacion en la fabricacion de sistemas de amortiguamiento autocontrolables.

  13. Fluid mechanics in the perivascular space.

    Science.gov (United States)

    Wang, Peng; Olbricht, William L

    2011-04-07

    Perivascular space (PVS) within the brain is an important pathway for interstitial fluid (ISF) and solute transport. Fluid flowing in the PVS can affect these transport processes and has significant impacts on physiology. In this paper, we carry out a theoretical analysis to investigate the fluid mechanics in the PVS. With certain assumptions and approximations, we are able to find an analytical solution to the problem. We discuss the physical meanings of the solution and particularly examine the consequences of the induced fluid flow in the context of convection-enhanced delivery (CED). We conclude that peristaltic motions of the blood vessel walls can facilitate fluid and solute transport in the PVS.

  14. Identification of bovine prolactin in seminal fluid, and expression and localization of the prolactin receptor and prolactin-inducible protein in the testis and epididymis of bulls exposed to ergot alkaloids.

    Science.gov (United States)

    Pratt, S L; Calcatera, S M; Stowe, H M; Dimmick, M A; Schrick, F N; Duckett, S K; Andrae, J G

    2015-03-01

    The objectives of this study were to determine (1) the presence and expression levels of bovine prolactin receptor (PRLR) and prolactin-inducible protein (PIP) in bovine testis and epididymis, and (2) the presence and concentrations of prolactin (PRL) present in seminiferous fluid in bulls consuming diets with (E+) or without (E-) ergot alkaloids. Bulls (n = 8) were sacrificed after 126 days (group A) of E+ or E- treatment or 60 days after all bulls (n = 6) were switched to the E- ration (group B). End point and real-time quantitative reverse transcription-polymerase chain reaction and immunohistochemistry were conducted on testis and epididymis samples to establish the presence and relative expression of PRLR and PIP. Seminal fluid samples obtained from bulls consuming E- and E+ diets were subjected to RIA for PRL. Both PIP and PRLR were present in testis and epididymis as determined by reverse transcription-polymerase chain reaction and immunohistochemistry. Prolactin-inducible protein mRNA abundance was affected by time of slaughter in testis and epididymis head, respectively (P Prolactin receptor mRNA expression was affected by time of slaughter in the epididymis (P < 0.05) and differed in testis samples because of treatment (P < 0.05). Radioimmunoassay establishes the presence of PRL in seminal fluid; however, differences in the concentration of PRL over two separate studies were inconsistent, possibly because of differences in diet. The presence and localization of the PRLR are consistent with expression data reported for other species, and the presence of PIP and PRL in seminal fluid is consistent with data generated in humans.

  15. Noncommutative geometry and fluid dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Das, Praloy; Ghosh, Subir [Indian Statistical Institute, Physics and Applied Mathematics Unit, Kolkata (India)

    2016-11-15

    In the present paper we have developed a Non-Commutative (NC) generalization of perfect fluid model from first principles, in a Hamiltonian framework. The noncommutativity is introduced at the Lagrangian (particle) coordinate space brackets and the induced NC fluid bracket algebra for the Eulerian (fluid) field variables is derived. Together with a Hamiltonian this NC algebra generates the generalized fluid dynamics that satisfies exact local conservation laws for mass and energy, thereby maintaining mass and energy conservation. However, nontrivial NC correction terms appear in the charge and energy fluxes. Other non-relativistic spacetime symmetries of the NC fluid are also discussed in detail. This constitutes the study of kinematics and dynamics of NC fluid. In the second part we construct an extension of the Friedmann-Robertson-Walker (FRW) cosmological model based on the NC fluid dynamics presented here. We outline the way in which NC effects generate cosmological perturbations bringing about anisotropy and inhomogeneity in the model. We also derive a NC extended Friedmann equation. (orig.)

  16. In vivo and in vitro effects of tea extracts on enterotoxigenic Escherichia coli-induced intestinal fluid loss in animal models

    NARCIS (Netherlands)

    Bruins, M.J.; Cermak, R.; Kiers, J.L.; Meulen, van der J.; Amelsvoort, van J.M.M.; Klinken, B.J.

    2006-01-01

    OBJECTIVES: Enterotoxigenic Escherichia coli (ETEC) infection is a major cause of dehydrating diarrhoea in infants and early-weaned piglets living under subhygienic conditions. We studied the effect of different tea types and subfractions on the intestinal fluid and electrolyte losses involved in ET

  17. Downhole Fluid Analyzer Development

    Energy Technology Data Exchange (ETDEWEB)

    Bill Turner

    2006-11-28

    A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.

  18. Thermophysical Properties of Fluids and Fluid Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sengers, Jan V.; Anisimov, Mikhail A.

    2004-05-03

    The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.

  19. HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT DYTRAN ANALYSIS OF SEISMICALLY INDUCED FLUID STRUCTURE INTERACTION IN A HANFORD DOUBLE SHELL PRIMARY TANK

    Energy Technology Data Exchange (ETDEWEB)

    MACKEY, T.C.

    2006-03-14

    M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project-DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). The overall seismic analysis of the DSTs is being performed with the general-purpose finite element code ANSYS'. The global model used for the seismic analysis of the DSTs includes the DST structure, the contained waste, and the surrounding soil. The seismic analysis of the DSTs must address the fluid-structure interaction behavior and sloshing response of the primary tank and contained liquid. ANSYS has demonstrated capabilities for structural analysis, but has more limited capabilities for fluid-structure interaction analysis. The purpose of this study is to demonstrate the capabilities and investigate the limitations of the finite element code MSC.Dytranz for performing a dynamic fluid-structure interaction analysis of the primary tank and contained waste. To this end, the Dytran solutions are benchmarked against theoretical solutions appearing in BNL 1995, when such theoretical solutions exist. When theoretical solutions were not available, comparisons were made to theoretical solutions to similar problems, and to the results from ANSYS simulations. Both rigid tank and flexible tank configurations were analyzed with Dytran. The response parameters of interest that are evaluated in this study are the total hydrodynamic reaction forces, the impulsive and convective mode frequencies, the waste

  20. Effect of Glycerol-Induced Hyperhydration on Body Fluid and Electrolyte Balance in Endurance Athletes during The Course of Treadmill Exercise Performed at 30 °C for 90 minute

    Directory of Open Access Journals (Sweden)

    Mehmet Pense

    Full Text Available The purpose of this study was to determine the effects of glycerol-induced hyperhydration on body fluid and electrolyte balancein endurance athletes during the course of treadmill exercise performed at 30C for 90min. 9 elit level male long-distance runnerwere participated to this study (age: x = 18,7 ±1,3 years, height: x = 170,7±5,2 cm, body weight: x = 58,8±6,6 kg, VO2max:63,94±3,04 ml.kg-1. First, VO2max of the subjects were determined with an incremental treadmill running protocol. In a randomized,double-blind cross over experimental design subjects were tested three times with 3 days intervals (wash out following ingestion of20 ml.kg-1BW of three different mixture of solutions: 1 diluted sports drink with 1.2 gr.kg-1BW glycerol (GS 2 diluted sports drink(SP and 3 aspartame flavored distilled water (WS. Exercise trials were conducted at an exercise intensity of 65% maximal oxygenconsumption (VO2max for 90 min at 30±1.8C and 25-35% relative humidity. Blood and urin samples were collected pre and postfluid ingestion, at the 30th, 60th and 90th min of exercise trials to determine body fluid and electrolyte balance. Data were analyzedusing two-way (treatmentxtime analyses of variance (ANOVA. Significance level was defined as p0.05. Inconclusion, glycerol-induced hyperhydration has no advantage compared to the other solutions ingested on body fluid andelectrolyte balance in endurance athletes during 90 min of treadmill run.

  1. A stable and convergent scheme for viscoelastic flow in contraction channels

    Energy Technology Data Exchange (ETDEWEB)

    Trebotich, David; Colella, Phillip; Miller, Gregory

    2004-02-15

    We present a new algorithm to simulate unsteady viscoelastic flows in abrupt contraction channels. In our approach we split the viscoelastic terms of the Oldroyd-B constitutive equation using Duhamel's formula and discretize the resulting PDEs using a semi-implicit finite difference method based on a Lax-Wendroff method for hyperbolic terms. In particular, we leave a small residual elastic term in the viscous limit by design to make the hyperbolic piece well-posed. A projection method is used to impose the incompressibility constraint. We are able to compute the full range of elastic flows in an abrupt contraction channel--from the viscous limit to the elastic limit--in a stable and convergent manner for elastic Mach numbers less than one. We demonstrate the method for unsteady Oldroyd-B and Maxwell fluids in planar contraction channels.

  2. A Numerical Model of Viscoelastic Layer Entrainment by Airflow in Cough

    Science.gov (United States)

    Mitran, Sorin M.

    2008-07-01

    Coughing is an alternative mode of ensuring mucus clearance in the lung when normal cilia induced flow breaks down. A numerical model of this process is presented with the following aspects. (1) A portion of the airway comprising the first three bronchus generations is modeled as radially reinforced elastic tubes. Elasticity equations are solved to predict airway deformation under effect of airway pressure. (2) The compressible, turbulent flow induced by rapid lung contraction is modeled by direct numerical simulation for Reynolds numbers in the range 5,000-10,000 and by Large Eddy Simulation for Reynolds numbers in the range 5,000-40,000. (3) A two-layer model of the airway surface liquid (ASL) covering the airway epithelial layer is used. The periciliary liquid (PCL) in direct contact with the epithelial layer is considered to be a Newtonian fluid. Forces modeling cilia beating can act upon this layer. The mucus layer between the PCL and the interior airflow is modeled as an Oldroyd-B fluid. The overall computation is a fluid-structure interaction simulation that tracks changes in ASL thickness and airway diameters that result from impulsive airflow boundary conditions imposed at bronchi ends. In particular, the amount of mucus that is evacuated from the system is computed as a function of cough intensity and mucus rheological properties.

  3. Fluid migration in the subduction zone: a coupled fluid flow approach

    Science.gov (United States)

    Wang, Hongliang; Huismans, Ritske; Rondenay, Stéphane

    2016-04-01

    Subduction zone are the main entry point of water into earth's mantle and play an important role in the global water cycle. The progressive release of water by metamorphic dehydration induce important physical-chemical process in the subduction zone, such as hydrous melting, hydration and weakening of the mantle wedge, creation of pore fluid pressures that may weaken the subduction interface and induce earthquakes. Most previous studies on the role of fluids in subduction zones assume vertical migration or migration according to the dynamic pressure in the solid matrix without considering the pore fluid pressure effect on the deformation of the solid matrix. Here we investigate this interaction by explicitly modeling two-phase coupled poro-plastic flow during subduction. In this approach, the fluid migrates by compaction and decompaction of the solid matrix and affects the subduction dynamics through pore fluid pressure dependent frictional-plastic yield. Our preliminary results indicate that: 1) the rate of fluid migration depends strongly on the permeability and the bulk viscosity of the solid matrix, 2) fluid transfer occurs preferentially along the slab and then propagates into the mantle wedge by viscous compaction driven fluid flow, 3) fluid transport from the surface to depth is a prerequisite for producing high fluid pore pressures and associated hydration induced weakening of the subduction zone interface.

  4. Wellbottom fluid implosion treatment system

    Energy Technology Data Exchange (ETDEWEB)

    Brieger, Emmet F. (HC 67 Box 58, Nogal, NM 88341)

    2001-01-01

    A system for inducing implosion shock forces on perforation traversing earth formations with fluid pressure where an implosion tool is selected relative to a shut in well pressure and a tubing pressure to have a large and small area piston relationship in a well tool so that at a predetermined tubing pressure the pistons move a sufficient distance to open an implosion valve which permits a sudden release of well fluid pressure into the tubing string and produces an implosion force on the perforations. A pressure gauge on the well tool records tubing pressure and well pressure as a function of time.

  5. Fluid-induced Forces in Centrifugal Pump under Given Rotordynamic Parameters%给定转子动力学参数的离心泵内部流体力研究

    Institute of Scientific and Technical Information of China (English)

    潘中永; 陈士星; 吴燕兰; 张大庆; 李彦军

    2013-01-01

    通过数值模拟和试验,研究了涡动情况下偏心距和涡动频率比对离心泵内外特性的影响.在给定一系列转子动力学参数条件下,采用RNG k-ε湍流模型对包含前后泵腔在内的全流场进行数值模拟,分析了偏心距对离心泵外特性的影响和涡动频率比对离心泵内部流场的影响,研究了离心泵内部流体力的分布情况以及偏心距和涡动频率比对离心泵内部流体力的影响.研究结果表明:随着偏心距的增大,泵高效区范围变窄;流体力的法向分力Fn、切向分力Ft均与涡动频率比ω/Ω近似呈二次函数关系,这种二次函数关系与偏心距大小相关;叶轮受到的流体力主要来源于叶轮内部流体,且叶轮内部流体周向压力分布不均.对于离心泵来说,当ω/Ω>O时,叶轮内的旋涡较少,水力损失较小,对涡动效果有抑制作用;当ω/Ω<0时,叶轮内旋涡较多,水力损失较大,对涡动效果有促进作用.%The effect of eccentricity and whirl frequency ratio on the internal and external characteristics of a centrifugal pump was investigated numerically and experimentally.Under a series of given rotordynamic parameters,the RNG k-ε turbulence model was applied in the simulation of whole flow field including front and back shrouds of pump.The influence of eccentricity on the external characteristics of the centrifugal pump and the impact of whirl frequency ratio on the internal flow field were analyzed.Then the distribution of the fluid-induced forces in the centrifugal pump and the effect of eccentricity and whirl frequency ratio on the fluid-induced forces in the centrifugal pump were investigated.According to the results,it could be drawn that the high efficiency area of centrifugal pump narrows as the eccentricity increases.Normal fluid force component Fn and tangential fluid force component Ft were both approximate into a quadratic function relation against the whirl frequency ratio

  6. The Protective Effects of the Supercritical-Carbon Dioxide Fluid Extract of Chrysanthemum indicum against Lipopolysaccharide-Induced Acute Lung Injury in Mice via Modulating Toll-Like Receptor 4 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xiao-Li Wu

    2014-01-01

    Full Text Available The supercritical-carbon dioxide fluid extract of Chrysanthemum indicum Linné. (CFE has been demonstrated to be effective in suppressing inflammation. The aim of this study is to investigate the preventive action and underlying mechanisms of CFE on acute lung injury (ALI induced by lipopolysaccharide (LPS in mice. ALI was induced by intratracheal instillation of LPS into lung, and dexamethasone was used as a positive control. Results revealed that pretreatment with CFE abated LPS-induced lung histopathologic changes, reduced the wet/dry ratio and proinflammatory cytokines productions (TNF-α, IL-1β, and IL-6, inhibited inflammatory cells migrations and protein leakages, suppressed the levels of MPO and MDA, and upregulated the abilities of antioxidative enzymes (SOD, CAT, and GPx. Furthermore, the pretreatment with CFE downregulated the activations of NF-κB and the expressions of TLR4/MyD88. These results suggested that CFE exerted potential protective effects against LPS-induced ALI in mice and was a potential therapeutic drug for ALI. Its mechanisms were at least partially associated with the modulations of TLR4 signaling pathways.

  7. Changes in the rate of formation and resistance to reabsorption of cerebrospinal fluid during deliberate hypotension induced with adenosine or hemorrhage.

    Science.gov (United States)

    Shapira, Y; Artru, A A; Lam, A M

    1992-03-01

    Adenosine is recommended for induction of deliberate hypotension. Although its effects on brain vasculature and metabolism and intracranial pressure have been reported, its effects on cerebrospinal fluid dynamics have not. In this study the rate of cerebrospinal fluid formation (Vf), resistance to reabsorption of cerebrospinal fluid (Ra), and electroencephalogram (EEG) activity were determined in rabbits before and during decrease of cerebral perfusion pressure (CPP) with intravenous (iv) adenosine or hemorrhage. In the adenosine group (n = 6), Vf and Ra were determined at control CPP, at CPP of 50, 35, and 28 mmHg achieved with iv adenosine, and at CPP greater than 60 mmHg achieved with iv adenosine combined with iv phenylephrine. In the hemorrhage group (n = 6), Vf and Ra were determined at the first four experimental conditions only. Control values for Vf (9 +/- 3 and 9 +/- 4 microliter.min-1, mean +/- SD) and Ra (428 +/- 567 and 412 +/- 144 cmH2O.ml-1.min) did not differ between groups. In the adenosine group, Vf did not change significantly when CPP was decreased. However, in the hemorrhage group, Vf decreased significantly at CPP of 50 and 35 mmHg and became unmeasurable at CPP of 28 mmHg. Ra did not change significantly in either group. An increase of low-frequency (0.5-3.0 Hz) EEG activity and/or decrease of higher-frequency (3.5-30 Hz) EEG activity occurred at CPP of 28 mmHg in the adenosine group and at CPP of 35 mmHg in the hemorrhage group.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. The traits of the amniotic fluid after induced labor by oxytocin in full-term pregnancy%足月妊娠缩宫素引产对羊水性状的影响

    Institute of Scientific and Technical Information of China (English)

    李婵娟; 赵玉华

    2015-01-01

    目的:评价足月妊娠用缩宫素引产对羊水性状的影响,指导缩宫素引产的临床应用。方法将足月妊娠采用缩宫素引产的孕妇123例分为3组,缩宫素引产48 h内分娩(Ⅰ组),48 h~72 h内分娩(Ⅱ组),>72 h分娩(Ⅲ组),观察其羊水性状。结果Ⅰ组,羊水性状为:清,Ⅰ~Ⅱ度,Ⅲ度,分别为60.0%,29.3%,9.8%;Ⅱ组为45.0%,37.5%,17.5%,Ⅲ组为23.8%,28.6%,47.6%。结论足月妊娠采用缩宫素引产>72 h分娩比72 h内分娩的孕妇,其羊水明显污染。对于缩宫素引产>72 h分娩的孕妇要加强监护,或改用其他方式终止妊娠。%Objective To evaluate influences of induced labor by oxytocin in the full-term pregnancy on the traits of the amniotic fluid,and guide the clinical application of induced labor by oxytocin. Methods To observe 123 pregnant women who were induced labor by oxytocin in full-term pregnancy and divided into three groups:delivery within 48 hours because of induced labor by oxytocin(groupⅠ),delivery within 48-72 hours(groupⅡ),longer than 72 hours of birth (groupⅢ).And observe properties of the amniotic fluid in each group.Results Amniotic fluid properties in groupⅠwere as follows:clear, Ⅰ-Ⅱdegree andⅢdegree which were 60.0%,29.3%and 9.8%respectively;that in groupⅡwere 45.0%,45.0%,and 45.0%respectively;and that in groupⅢwere 23.8%,28.6%and 47.6%respectively. Conclusion The amniotic fluid of women after induced labor by oxytocin in full-term pregnancy is contaminated more obviously in delivery longer than 72 hours than that within 72 hours. Pregnant women after induced labor by oxytocin longer than 72 hours should be strengthened to monitor, or switch to other methods.

  9. Alterações no líquido sinovial do joelho de cães com osteoartrite induzida pelo modelo Pond e Nuki Synovial fluid changes in the dog knee with osteoarthritis induced by Pond and Nuki model

    Directory of Open Access Journals (Sweden)

    F. De Biasi

    2001-10-01

    Full Text Available Avaliaram-se as alterações do líquido sinovial do joelho de 19 cães submetidos à desmotomia unilateral do cruzado cranial, baseado no modelo experimental de Pond & Nuki, colhido e analisado aos 30 dias de pós-operatório. Cinco animais foram analisados novamente aos 90 dias de pós-operatório. As características analisadas foram volume, cor, aspecto, densidade, pH, proteínas, fibrinogênio, coágulo de mucina, contagem de hemácias e contagem total e diferencial de células nucleadas. O líquido sinovial apresentou padrão inflamatório que persistiu durante todo o período de observação, com efusão articular. Houve aumento na contagem de células nucleadas e na concentração de fibrinogênio aos 90 dias. A qualidade da precipitação da mucina apresentou melhora aos 90 dias quando comparada à de 30 dias, porém ainda marcadamente anormal. Foi possível concluir que até 90 dias de pós-operatório no modelo utilizado o fluído sinovial apresenta características inflamatórias e não degenerativas.The purpose of this study was to evaluate the changes in knee synovial fluid of 19 dogs with experimentally-induced cranial cruciate ligament rupture, based on Pond & Nuki model. Synovial fluid was achieved and analyzed at 30 days postoperative time. Five animals had further synovial fluid evaluation at 90 days postoperatively. The characteristics observed were color, turbidity, density, pH, protein, fibrinogen, mucin clot, cell count and citology. The synovial fluid exhibited an inflammatory pattern during the postoperative observation time and joint effusion was observed. An increased number of nucleated cells and increased fibrinogen concentration were observed at 90 days when compared to 30 days after desmotomy. Although severely abnormal, an improvement of the mucin clot was observed at 90 days. It can be concluded that synovial fluid in this experimental model, showed inflammatory and no degenerative changes until 90 days

  10. ACUTE OZONE-INDUCED INFLAMMATORY GENE EXPRESSION IN THE RAT LUNG IS NOT RELATED TO LEVELS OF ANTIOXIDANTS IN THE LAVAGE FLUID

    Science.gov (United States)

    ABSTRACT BODY: Ozone causes oxidative stress and lung inflammation. We hypothesized that rat strains with or without genetic susceptibility to cardiovascular disease will have different antioxidant levels in alveolar lining, and that ozone induced inflammatory gene expression wil...

  11. Structure evolution in electrorheological fluids

    Science.gov (United States)

    Qian, Bian; Helal, Ahmed; Telleria, Maria; Murphy, Mike; Strauss, Marc; McKinley, Gareth; Hosoi, Anette

    2012-11-01

    Enhanced knowledge of the transient behavior and characteristics of electrorheological (ER) fluids subject to time dependent electric fields carries the potential to advance the design of fast actuated hydraulic devices. In this study, the dynamic response of electrorheological fluid flows in rectilinear microchannels was investigated experimentally. Using high-speed microscopic imaging, the evolution of particle aggregates in ER fluids subjected to temporally stepwise electric fields was visualized. Nonuniform growth of the particle structures in the channel was observed and correlated to field strength and flow rate. Two competing time scales for structure growth were identified. Guided by experimental observations, we develop a phenomenological model to quantitatively describe and predict the evolution of microscale structures and the concomitant induced pressure gradient. This work is supported by DARPA M3.

  12. Ultraviolet light-responsive photorheological fluids: as a new class of smart fluids

    Science.gov (United States)

    Cho, Min-Young; Kim, Ji-Sik; Choi, Hyoung Jin; Choi, Seung-Bok; Kim, Gi-Woo

    2017-05-01

    We present a comprehensive introduction to the photorheological (PR) fluids whose rheological behavior can be changed by ultraviolet (UV) light with a wavelength of 365 nm. When the PR fluid was exposed to UV light, the viscosity of the fluid decreased, while the viscosity recovered to its initial value when UV light was turned off, indicating that the viscosity of these types of fluids can be reversible and tunable by UV light. Contrary to conventional smart fluids, such as electrorheological and magnetorheological fluids, PR fluid does not suffer from a phase splitting problem because it exists in a single-phase solution. Additionally, the PR fluid does not require any contact component, such as electrodes, and electric wires that are essential components for conventional smart fluids. In this work, the PR fluids were synthesized by doping lecithin/sodium deoxycholate reverse micelles with a photo-chromic spiropyran compound. It is demonstrated that the viscosity changes of PR fluids can be induced by UV light, and their rheological properties are examined in detail. In addition, an example of tailoring rheological properties using photoluminescence was introduced for improved response time. One of the potential applications, such as microfluidic flow control using the PR fluids, is also briefly presented.

  13. Auxillary Fluid Flowmeter

    DEFF Research Database (Denmark)

    RezaNejad Gatabi, Javad; Forouzbakhsh, Farshid; Ebrahimi Darkhaneh, Hadi

    2010-01-01

    and with measuring its travel time between two different positions, its velocity could be calculated. Given the velocity of the auxiliary fluid, the velocity of the main fluid could be calculated. Using this technique, it is possible to measure the velocity of any kind of fluids, if an appropriate auxiliary fluid...

  14. Fluid mechanics in fluids at rest.

    Science.gov (United States)

    Brenner, Howard

    2012-07-01

    Using readily available experimental thermophoretic particle-velocity data it is shown, contrary to current teachings, that for the case of compressible flows independent dye- and particle-tracer velocity measurements of the local fluid velocity at a point in a flowing fluid do not generally result in the same fluid velocity measure. Rather, tracer-velocity equality holds only for incompressible flows. For compressible fluids, each type of tracer is shown to monitor a fundamentally different fluid velocity, with (i) a dye (or any other such molecular-tagging scheme) measuring the fluid's mass velocity v appearing in the continuity equation and (ii) a small, physicochemically and thermally inert, macroscopic (i.e., non-Brownian), solid particle measuring the fluid's volume velocity v(v). The term "compressibility" as used here includes not only pressure effects on density, but also temperature effects thereon. (For example, owing to a liquid's generally nonzero isobaric coefficient of thermal expansion, nonisothermal liquid flows are to be regarded as compressible despite the general perception of liquids as being incompressible.) Recognition of the fact that two independent fluid velocities, mass- and volume-based, are formally required to model continuum fluid behavior impacts on the foundations of contemporary (monovelocity) fluid mechanics. Included therein are the Navier-Stokes-Fourier equations, which are now seen to apply only to incompressible fluids (a fact well-known, empirically, to experimental gas kineticists). The findings of a difference in tracer velocities heralds the introduction into fluid mechanics of a general bipartite theory of fluid mechanics, bivelocity hydrodynamics [Brenner, Int. J. Eng. Sci. 54, 67 (2012)], differing from conventional hydrodynamics in situations entailing compressible flows and reducing to conventional hydrodynamics when the flow is incompressible, while being applicable to both liquids and gases.

  15. Videotapes and Movies on Fluid Dynamics and Fluid Machines

    OpenAIRE

    Carr, Bobbie; Young, Virginia E.

    1996-01-01

    Chapter 17 of Handbook of Fluid Dynamics and Fluid Machinery: Experimental and Computational Fluid Dynamics, Volume 11. A list of videorecordings and 16mm motion pictures about Fluid Dynamics and Fluid Machines.

  16. [Cell apoptosis and expression of hypoxia-inducible transcription factor-1 alpha in kidney tissue after severe burn with delayed fluid resuscitation in rats in areas of different altitude].

    Science.gov (United States)

    Jiang, Jiang; Liu, Yi; Zhang, Shi-fan; Cai, Qian; Zhang, Xian-ying; Zhang, Bin; Xiao, Bin

    2008-07-01

    To explore the relationship of cell apoptosis and expression regularity of hypoxia-inducible transcription factor (HIF)-1 alpha after severe burn with delayed fluid resuscitation in areas of different altitude. A total of 240 male Wistar rats, which were raised in areas of different altitude (1,517 and 3,840 meters), were employed as the experimental models [They received a 30% total body surface area (TBSA)III degree scald injury], and then they were randomly divided into 3 groups: delayed fluid resuscitation group (DFR, n=50), immediate fluid resuscitation group (IFR, n=60) and control group (CG, n=10). Renal tissue samples were harvested at 1, 6, 12, 24, 72 and 168 hours after burn, respectively. Cell apoptosis was detected by tissue chip technology and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL). The expression of HIF-1 alpha was assessed by immunohistochemistry and image analysis. With increase in altitude, cellular edema, degeneration, necrosis and disintegration of renal tissue were gradually worsening, the capillaries of renal glomeruli became dilated and engorged, with degeneration and necrosis of endothelial cells, engorgement and edema of renal interstitium, and infiltration of inflammatory cells. Pathological changes in DFR group were more serious than that of IFR group. Cell apoptosis and the expression of HIF-1 alpha were both enhanced, the latter mainly appeared in nuclei of renal cells, and they were more marked at 3,840 meters compared with those at 1,517 meters. They were more marked in experimental groups than in control group, especially so in DFR group (Pkidney cell apoptosis.

  17. Melt- versus fluid-induced metasomatism in spinel to garnet wedge peridotites (Ulten Zone, Eastern Italian Alps): clues from trace element and Li abundances

    Science.gov (United States)

    Scambelluri, M.; Hermann, J.; Morten, L.; Rampone, E.

    2006-04-01

    The peridotite bodies of the Ulten Zone (Upper Austroalpine, Italian Eastern Alps) are enclosed in Variscan migmatites and derive from a mantle wedge environment. They display the progressive transformation of porphyroclastic spinel peridotites ( T=1,200°C; P=1.5 GPa) into fine-grained garnet-amphibole peridotites ( T=850°C; P=3 GPa). Detailed bulk-rock and mineral trace element analyses of a sample suite documenting the entire metamorphic evolution of the peridotites revealed several stages of metasomatism. The spinel peridotites derive from a depleted mantle that became enriched in some large ion lithophile element (LILE) and light rare earth elements (LREE). The same signature pertains to clinopyroxene and orthopyroxene, indicating that this metasomatic signature was acquired at the recorded temperature of 1,200°C. Such a temperature is considerably above the wet peridotite solidus and hence the metasomatic agent must have been a hydrous melt. Moreover, the Li-enrichment of the spinel-facies pyroxenes (up to 24 ppm Li) reflects disequilibrium distribution after exchange with a presumably mafic melt. cpx/opx D Li=3-7 and cpx/ol D Li=2.7-8 indicate that the spinel-facies clinopyroxene hosts higher Li amounts than the coexisting minerals. LREE fractionation, variable LREE enrichment, LILE enrichment with respect to HFSE (average clinopyroxene Pb N /Nb N =16-90) in spinel lherzolites can be related to chromatographic effects of porous melt flow. The significant enrichment of pyroxenes from the spinel lherzolites in Pb, U and Li indicates that the metasomatic melt was subduction-related. All these features suggest that the spinel lherzolites formed a mantle wedge layer percolated by melts carrying recycled crustal components and rising from a deeper source of subduction magmas. The garnet + amphibole peridotites equilibrated at temperatures well below the wet solidus in the presence of an aqueous fluid. Bulk-rock trace element patterns display pronounced positive

  18. Magnetic fields for fluid motion.

    Science.gov (United States)

    Weston, Melissa C; Gerner, Matthew D; Fritsch, Ingrid

    2010-05-01

    Three forces induced by magnetic fields offer unique control of fluid motion and new opportunities in microfluidics. This article describes magnetoconvective phenomena in terms of the theory and controversy, tuning by redox processes at electrodes, early-stage applications in analytical chemistry, mature applications in disciplines far afield, and future directions for micro total analysis systems. (To listen to a podcast about this article, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html .).

  19. HANFORD DST THERMAL & SEISMIC PROJECT ANSYS BENCHMARK ANALYSIS OF SEISMIC INDUCED FLUID STRUCTURE INTERACTION IN A HANFORD DOUBLE SHELL PRIMARY TANK

    Energy Technology Data Exchange (ETDEWEB)

    MACKEY, T.C.

    2006-03-14

    M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project-DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). The overall seismic analysis of the DSTs is being performed with the general-purpose finite element code ANSYS. The overall model used for the seismic analysis of the DSTs includes the DST structure, the contained waste, and the surrounding soil. The seismic analysis of the DSTs must address the fluid-structure interaction behavior and sloshing response of the primary tank and contained liquid. ANSYS has demonstrated capabilities for structural analysis, but the capabilities and limitations of ANSYS to perform fluid-structure interaction are less well understood. The purpose of this study is to demonstrate the capabilities and investigate the limitations of ANSYS for performing a fluid-structure interaction analysis of the primary tank and contained waste. To this end, the ANSYS solutions are benchmarked against theoretical solutions appearing in BNL 1995, when such theoretical solutions exist. When theoretical solutions were not available, comparisons were made to theoretical solutions of similar problems and to the results from Dytran simulations. The capabilities and limitations of the finite element code Dytran for performing a fluid-structure interaction analysis of the primary tank and contained waste were explored in a parallel investigation (Abatt 2006). In conjunction with the results of the

  20. Interfacial instabilities in vibrated fluids

    Science.gov (United States)

    Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier

    2016-07-01

    Vibrations induce a range of different interfacial phenomena in fluid systems depending on the frequency and orientation of the forcing. With gravity, (large) interfaces are approximately flat and there is a qualitative difference between vertical and horizontal forcing. Sufficient vertical forcing produces subharmonic standing waves (Faraday waves) that extend over the whole interface. Horizontal forcing can excite both localized and extended interfacial phenomena. The vibrating solid boundaries act as wavemakers to excite traveling waves (or sloshing modes at low frequencies) but they also drive evanescent bulk modes whose oscillatory pressure gradient can parametrically excite subharmonic surface waves like cross-waves. Depending on the magnitude of the damping and the aspect ratio of the container, these locally generated surfaces waves may interact in the interior resulting in temporal modulation and other complex dynamics. In the case where the interface separates two fluids of different density in, for example, a rectangular container, the mass transfer due to vertical motion near the endwalls requires a counterflow in the interior region that can lead to a Kelvin-Helmholtz type instability and a ``frozen wave" pattern. In microgravity, the dominance of surface forces favors non-flat equilibrium configurations and the distinction between vertical and horizontal applied forcing can be lost. Hysteresis and multiplicity of solutions are more common, especially in non-wetting systems where disconnected (partial) volumes of fluid can be established. Furthermore, the vibrational field contributes a dynamic pressure term that competes with surface tension to select the (time averaged) shape of the surface. These new (quasi-static) surface configurations, known as vibroequilibria, can differ substantially from the hydrostatic state. There is a tendency for the interface to orient perpendicular to the vibrational axis and, in some cases, a bulge or cavity is induced

  1. Intravenous grafts of amniotic fluid-derived stem cells induce endogenous cell proliferation and attenuate behavioral deficits in ischemic stroke rats.

    Directory of Open Access Journals (Sweden)

    Naoki Tajiri

    Full Text Available We recently reported isolation of viable rat amniotic fluid-derived stem (AFS cells [1]. Here, we tested the therapeutic benefits of AFS cells in a rodent model of ischemic stroke. Adult male Sprague-Dawley rats received a 60-minute middle cerebral artery occlusion (MCAo. Thirty-five days later, animals exhibiting significant motor deficits received intravenous transplants of rat AFS cells or vehicle. At days 60-63 post-MCAo, significant recovery of motor and cognitive function was seen in stroke animals transplanted with AFS cells compared to vehicle-infused stroke animals. Infarct volume, as revealed by hematoxylin and eosin (H&E staining, was significantly reduced, coupled with significant increments in the cell proliferation marker, Ki67, and the neuronal marker, MAP2, in the dentate gyrus (DG [2] and the subventricular zone (SVZ of AFS cell-transplanted stroke animals compared to vehicle-infused stroke animals. A significantly higher number of double-labeled Ki67/MAP2-positive cells and a similar trend towards increased Ki67/MAP2 double-labeling were observed in the DG and SVZ of AFS cell-transplanted stroke animals, respectively, compared to vehicle-infused stroke animals. This study reports the therapeutic potential of AFS cell transplantation in stroke animals, possibly via enhancement of endogenous repair mechanisms.

  2. Grape waste extract obtained by supercritical fluid extraction contains bioactive antioxidant molecules and induces antiproliferative effects in human colon adenocarcinoma cells.

    Science.gov (United States)

    Lazzè, Maria Claudia; Pizzala, Roberto; Gutiérrez Pecharromán, Francisco Javier; Gatòn Garnica, Paloma; Antolín Rodríguez, Juan Manuel; Fabris, Nicola; Bianchi, Livia

    2009-06-01

    Grape waste management is one of the main problems of winery industries, but, conversely, grape waste contains a high amount of polyphenols that might protect against human diseases related to oxidative stress, such as colorectal cancer. Therefore, the aim of this work was to investigate the antioxidant and antiproliferative activities of a grape waste extract obtained by supercritical fluid extraction. Because the beneficial effect of grape is related to its content of polyphenolic molecules, the extract was chemically characterized by high-performance liquid chromatography in order to assess its major bioactive components. The antioxidant activity of the grape extract was determined. The results showed that the grape extract presents a strong antiradical activity in the in vitro 2,2-diphenyl-1-picrylhydrazyl radical assay and protects against reactive oxygen species production in human colon adenocarcinoma cells (Caco-2). In contrast, the extract did not protect in the citronellal thermooxidation system and showed a weak protective action against lipid peroxidation in Caco-2 cells. The clonogenic assay and the cell cycle distribution analysis showed that the grape extract has a significant antiproliferative effect in a tumor cell line. These data indicate that grape extract is a promising product to be used as an anti-free radical agent and could exert a chemopreventive action.

  3. Cilia walls influence on peristaltically induced motion of magneto-fluid through a porous medium at moderate Reynolds number: Numerical study

    Directory of Open Access Journals (Sweden)

    R.E. Abo-Elkhair

    2017-04-01

    Full Text Available This article addresses, effects of a magneto-fluid through a Darcy flow model with oscillatory wavy walled whose inner surface is ciliated. The equations that governing the flow are modeled without using any approximations. Adomian Decomposition Method (ADM is used to evaluate the solution of our system of nonlinear partial differential equations. Stream function, velocity and pressure gradient components are obtained by using the vorticity formula. The effects for our arbitrary physical parameters on flow characteristics are analyzed by plotting diagrams and discussed in details. With the help of stream lines the trapping mechanism has also been discussed. The major outcomes for the ciliated channel walls are: The axial velocity is higher without a ciliated walls than that for a ciliated walls and an opposite behaviour is shown near the ciliated channel walls. The pressure gradients in both directions are higher for a ciliated channel walls. More numbers of the trapped bolus in the absent of the eccentricity of the cilia elliptic path.

  4. Interfacial fluid instabilities and Kapitsa pendula

    CERN Document Server

    Krieger, Madison Ski

    2015-01-01

    The onset and development of instabilities is one of the central problems in fluid mechanics. Here we develop a connection between instabilities of free fluid interfaces and inverted pendula. When acted upon solely by the gravitational force, the inverted pendulum is unstable. This position can be stabilised by the Kapitsa phenomenon, in which high-frequency low-amplitude vertical vibrations of the base creates a fictitious force which opposes the gravitational force. By transforming the dynamical equations governing a fluid interface into an appropriate pendulum, we demonstrate how stability can be induced in fluid systems by properly tuned vibrations. We construct a "dictionary"-type relationship between various pendula and the classical Rayleigh-Taylor, Kelvin-Helmholtz, Rayleigh-Plateau and the self-gravitational instabilities. This makes several results in control theory and dynamical systems directly applicable to the study of "tunable" fluid instabilities, where the critical wavelength depends on the e...

  5. Steady laminar flow of fractal fluids

    Science.gov (United States)

    Balankin, Alexander S.; Mena, Baltasar; Susarrey, Orlando; Samayoa, Didier

    2017-02-01

    We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived.

  6. Electrodynamics of a Cosmic Dark Fluid

    CERN Document Server

    Balakin, Alexander B

    2016-01-01

    Cosmic Dark Fluid is considered as a non-stationary medium, in which electromagnetic waves propagate, and magneto-electric field structures emerge and evolve. A medium - type representation of the Dark Fluid allows us to involve into analysis the concepts and mathematical formalism elaborated in the framework of classical covariant electrodynamics of continua, and to distinguish dark analogs of well-known medium-effects, such as optical activity, pyro-electricity, piezo-magnetism, electro- and magneto-striction and dynamo-optical activity. The Dark Fluid is assumed to be formed by a duet of a Dark Matter (a pseudoscalar axionic constituent) and Dark Energy (a scalar element); respectively, we distinguish electrodynamic effects induced by these two constituents of the Dark Fluid. The review contains discussions of ten models, which describe electrodynamic effects induced by Dark Matter and/or Dark Energy. The models are accompanied by examples of exact solutions to the master equations, correspondingly extende...

  7. Synovial fluid analysis

    Science.gov (United States)

    ... bursae (fluid-filled sacs in the joints), and tendon sheaths. After the joint area is cleaned, the ... HS. Synovial fluid analysis, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Gabriel SE, McInnes ...

  8. Amniotic fluid (image)

    Science.gov (United States)

    Amniotic fluid surrounds the growing fetus in the womb and protects the fetus from injury and temperature changes. ... of fetal movement and permits musculoskeletal development. The amniotic fluid can be withdrawn in a procedure called amniocentsis ...

  9. Pericardial Fluid Analysis

    Science.gov (United States)

    ... help diagnose the cause of inflammation of the pericardium (pericarditis) and/or fluid accumulation around the heart ( ... pressure within blood vessels or inflammation of the pericardium. An initial set of tests, including fluid protein ...

  10. Pericardial fluid Gram stain

    Science.gov (United States)

    ... staining a sample of fluid taken from the pericardium. This is the sac surrounding the heart to ... sample of fluid will be taken from the pericardium. This is done through a procedure called pericardiocentesis . ...

  11. Lectures on fluid mechanics

    CERN Document Server

    Shinbrot, Marvin

    2012-01-01

    Readable and user-friendly, this high-level introduction explores the derivation of the equations of fluid motion from statistical mechanics, classical theory, and a portion of the modern mathematical theory of viscous, incompressible fluids. 1973 edition.

  12. Electric fluid pump

    Science.gov (United States)

    Van Dam, Jeremy Daniel; Turnquist, Norman Arnold; Raminosoa, Tsarafidy; Shah, Manoj Ramprasad; Shen, Xiaochun

    2015-09-29

    An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.

  13. Non-integrating episomal plasmid-based reprogramming of human amniotic fluid stem cells into induced pluripotent stem cells in chemically defined conditions.

    Science.gov (United States)

    Slamecka, Jaroslav; Salimova, Lilia; McClellan, Steven; van Kelle, Mathieu; Kehl, Debora; Laurini, Javier; Cinelli, Paolo; Owen, Laurie; Hoerstrup, Simon P; Weber, Benedikt

    2016-01-01

    Amniotic fluid stem cells (AFSC) represent an attractive potential cell source for fetal and pediatric cell-based therapies. However, upgrading them to pluripotency confers refractoriness toward senescence, higher proliferation rate and unlimited differentiation potential. AFSC were observed to rapidly and efficiently reacquire pluripotency which together with their easy recovery makes them an attractive cell source for reprogramming. The reprogramming process as well as the resulting iPSC epigenome could potentially benefit from the unspecialized nature of AFSC. iPSC derived from AFSC also have potential in disease modeling, such as Down syndrome or β-thalassemia. Previous experiments involving AFSC reprogramming have largely relied on integrative vector transgene delivery and undefined serum-containing, feeder-dependent culture. Here, we describe non-integrative oriP/EBNA-1 episomal plasmid-based reprogramming of AFSC into iPSC and culture in fully chemically defined xeno-free conditions represented by vitronectin coating and E8 medium, a system that we found uniquely suited for this purpose. The derived AF-iPSC lines uniformly expressed a set of pluripotency markers Oct3/4, Nanog, Sox2, SSEA-1, SSEA-4, TRA-1-60, TRA-1-81 in a pattern typical for human primed PSC. Additionally, the cells formed teratomas, and were deemed pluripotent by PluriTest, a global expression microarray-based in-silico pluripotency assay. However, we found that the PluriTest scores were borderline, indicating a unique pluripotent signature in the defined condition. In the light of potential future clinical translation of iPSC technology, non-integrating reprogramming and chemically defined culture are more acceptable.

  14. Effect of simulated weightlessness on the expression of Cbfα1 induced by fluid shear stress in MG-63 osteosarcoma cells.

    Science.gov (United States)

    Yang, Z.; Zhang, S.; Wang, B.; Sun, X. Q.

    Objective The role of mechanical load in the functional regulation of osteoblasts becomes an emphasis in osseous biomechanical researches recently This study was aim to explore the effect of flow shear stress on the expression of Cbf alpha 1 in human osteosarcoma cells and to survey its functional alteration in simulated weightlessness Method After cultured for 72 h in two different gravitational environments i e 1G terrestrial gravitational condition and simulated weightlessness condition human osteosarcoma cells MG-63 were treated with 0 5 Pa or 1 5 Pa fluid shear stress FSS in a flow chamber for 15 30 60 min respectively The total RNA in cells was isolated Transcription PCR analysis was made to examine the gene expression of Cbf alpha 1 And the total protein of cells was extracted and the expression of Cbf alpha 1 protein was detected by means of Western Blotting Results MG-63 cultured in 1G condition reacted to FSS treatment with an enhanced expression of Cbf alpha 1 Compared with no FSS control group Cbf alpha 1 mRNA and protein expression increased significantly at 30 and 60 min with the treatment of FSS P 0 01 And there was remarkable difference on the Cbf alpha 1 mRNA and protein expression between the treatments of 0 5 Pa and 1 5 Pa FSS at 30 min or 60 min P 0 01 As to the osteoblasts cultured in simulated weightlessness by using clinostat the expression of Cbf alpha 1 was significantly different between 1G and simulated weightlessness conditions at each test time P 0 05 Compared with no FSS

  15. Fluid force transducer

    Science.gov (United States)

    Jendrzejczyk, Joseph A.

    1982-01-01

    An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

  16. Fluid and particle mechanics

    CERN Document Server

    Michell, S J

    2013-01-01

    Fluid and Particle Mechanics provides information pertinent to hydraulics or fluid mechanics. This book discusses the properties and behavior of liquids and gases in motion and at rest. Organized into nine chapters, this book begins with an overview of the science of fluid mechanics that is subdivided accordingly into two main branches, namely, fluid statics and fluid dynamics. This text then examines the flowmeter devices used for the measurement of flow of liquids and gases. Other chapters consider the principle of resistance in open channel flow, which is based on improper application of th

  17. Super-strong magneto-rheological fluids

    Science.gov (United States)

    Tao, R.

    2001-03-01

    A typical MR fluid is a suspension of magnetic particles of micrometer size in a liquid. Upon application of a strong magnetic field, the fluid turns into a solid. This process is reversible and the response time is of milliseconds. MR fluids presently have a yield shear stress around 80 kPa, which is adequate for applications in shock absorbers and vibration dampers, but is inadequate for automobile clutch etc. Efforts in searching for new materials in the past decades came with limited results. Thus we have developed a new approach to change the microstructure of MR fluids and make them super-strong. It is well known that under a strong magnetic field, the ideal structure of MR fluids is a body-centered tetragonal (bct) lattice. The mechanical strength of MR fluids strongly depends on the microstructure. A bct-lattice based thick column has a much higher yield stress than a single-chain structure. When a magnetic field is applied to a MR fluid, the particles first form chains. With time, the chains may aggregate into columns. However, the unassisted aggregation is not very useful, as it is slow and produces columns with a limited thickness. Our method is based on assisted aggregations. Immediately after a magnetic field is applied, we compress the MR fluid in the field direction before a shear force is applied. The compression pushes the induced chains together to form thick columns. This microstructure change greatly enhances the yield stress. The experiment on an iron-based MR fluid finds 800 kPa for the yield stress, ten times stronger than that without the compression. When the magnetic field is removed, the MR fluid still returns to the liquid state quickly. The upper limit of this structure-enhanced yield stress seems well above 800 kPa. The super-strong MR fluids are suitable for many industrial applications. *Supported by NSF Grant 0196022

  18. Steady laminar flow of fractal fluids

    Energy Technology Data Exchange (ETDEWEB)

    Balankin, Alexander S., E-mail: abalankin@ipn.mx [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Mena, Baltasar [Laboratorio de Ingeniería y Procesos Costeros, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Sisal, Yucatán, 97355 (Mexico); Susarrey, Orlando; Samayoa, Didier [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico)

    2017-02-12

    We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived. - Highlights: • Equations of Stokes flow of Newtonian fractal fluid are derived. • Pressure distribution in the Newtonian fractal fluid is derived. • Velocity distribution in Poiseuille flow of fractal fluid is found. • Velocity distribution in a steady Couette flow is established.

  19. Fluid cooled electrical assembly

    Science.gov (United States)

    Rinehart, Lawrence E.; Romero, Guillermo L.

    2007-02-06

    A heat producing, fluid cooled assembly that includes a housing made of liquid-impermeable material, which defines a fluid inlet and a fluid outlet and an opening. Also included is an electrical package having a set of semiconductor electrical devices supported on a substrate and the second major surface is a heat sink adapted to express heat generated from the electrical apparatus and wherein the second major surface defines a rim that is fit to the opening. Further, the housing is constructed so that as fluid travels from the fluid inlet to the fluid outlet it is constrained to flow past the opening thereby placing the fluid in contact with the heat sink.

  20. Spinning fluids reactor

    Science.gov (United States)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert

    2012-11-20

    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  1. Predicting phase shift effects for vibrating fluid-conveying pipes due to Coriolis forces and fluid pulsation

    DEFF Research Database (Denmark)

    Enz, Stephanie; Thomsen, Jon Juel

    2011-01-01

    displacement and approximate axial shift in vibration phase. The analytical predictions are tested against pure numerical solution using representative examples, showing good agreement. Fluid pulsations are predicted not to influence CFM accuracy, since proper signal filtering is seen to allow......Knowing the influence of fluid flow perturbations on the dynamic behavior of fluid-conveying pipes is of relevance, e.g., when exploiting flow-induced oscillations of pipes to determine the fluids mass flow or density, as done with Coriolis flow meters (CFM). This could be used in the attempts...... the determination of the correct mean phase shift. Large amplitude motions, which could influence CFM robustness, do not appear to be induced by the investigated fluid pulsation. Pulsating fluid of the combination resonance type could, however, influence CFMs robustness, if induced pipe motions go unnoticed...

  2. Cerebrospinal fluid levels of catecholamines and its metabolites in Parkinson's disease: Effect of L-DOPA treatment and changes in levodopa-induced dyskinesia.

    Science.gov (United States)

    Andersen, A D; Blaabjerg, M; Binzer, M; Kamal, A; Thagesen, H; Kjaer, T W; Stenager, E; Gramsbergen, J B

    2017-02-28

    Levodopa (L-DOPA, L-3,4-dihydroxyphenylalanine) is the most effective drug in the symptomatic treatment of Parkinson's disease (PD), but chronic use initiates a maladaptive process leading to L-DOPA-induced dyskinesia (LID). Risk factors for early onset LID include younger age, more severe disease at baseline and higher daily L-DOPA dose, but biomarkers to predict the risk of motor complications are not yet available. Here we investigated whether CSF levels of catecholamines and its metabolites are altered in PD patients with LID (PD-LID, n=8)) as compared to non-dyskinetic PD patients receiving L-DOPA (PD-L, n=6), or not receiving L-DOPA (PD-N, n=7) as well as non-PD controls (n=16). PD patients were clinically assessed using the Unified Parkinson's Disease Rating Scale and Unified Dyskinesia Rating Scale and CSF was collected after overnight fasting and 1-2 hours after oral intake of L-DOPA or other anti-Parkinson medication. CSF catecholamines and its metabolites were analyzed by HPLC with electrochemical detection. We observed (1) decreased levels of dihydroxyphenylacetic acid and homovanillic acid in PD patients not receiving L-DOPA (2) higher DA levels in LID as compared to controls (3) higher DA/L-DOPA and lower DOPAC/DA ratio's in LID as compared to PDL and (4) an age-dependent increase of DA and decrease of DOPAC/DA ratio in controls. These results suggest increased DA release from non-DA cells and deficient DA re-uptake in PD-LID. Monitoring DA and DOPAC in CSF of L-DOPA-treated PD patients may help identify patients at risk of developing LID. This article is protected by copyright. All rights reserved.

  3. Engineering Fracking Fluids with Computer Simulation

    Science.gov (United States)

    Shaqfeh, Eric

    2015-11-01

    There are no comprehensive simulation-based tools for engineering the flows of viscoelastic fluid-particle suspensions in fully three-dimensional geometries. On the other hand, the need for such a tool in engineering applications is immense. Suspensions of rigid particles in viscoelastic fluids play key roles in many energy applications. For example, in oil drilling the ``drilling mud'' is a very viscous, viscoelastic fluid designed to shear-thin during drilling, but thicken at stoppage so that the ``cuttings'' can remain suspended. In a related application known as hydraulic fracturing suspensions of solids called ``proppant'' are used to prop open the fracture by pumping them into the well. It is well-known that particle flow and settling in a viscoelastic fluid can be quite different from that which is observed in Newtonian fluids. First, it is now well known that the ``fluid particle split'' at bifurcation cracks is controlled by fluid rheology in a manner that is not understood. Second, in Newtonian fluids, the presence of an imposed shear flow in the direction perpendicular to gravity (which we term a cross or orthogonal shear flow) has no effect on the settling of a spherical particle in Stokes flow (i.e. at vanishingly small Reynolds number). By contrast, in a non-Newtonian liquid, the complex rheological properties induce a nonlinear coupling between the sedimentation and shear flow. Recent experimental data have shown both the shear thinning and the elasticity of the suspending polymeric solutions significantly affects the fluid-particle split at bifurcations, as well as the settling rate of the solids. In the present work, we use the Immersed Boundary Method to develop computer simulations of viscoelastic flow in suspensions of spheres to study these problems. These simulations allow us to understand the detailed physical mechanisms for the remarkable physical behavior seen in practice, and actually suggest design rules for creating new fluid recipes.

  4. Metalworking and machining fluids

    Science.gov (United States)

    Erdemir, Ali; Sykora, Frank; Dorbeck, Mark

    2010-10-12

    Improved boron-based metal working and machining fluids. Boric acid and boron-based additives that, when mixed with certain carrier fluids, such as water, cellulose and/or cellulose derivatives, polyhydric alcohol, polyalkylene glycol, polyvinyl alcohol, starch, dextrin, in solid and/or solvated forms result in improved metalworking and machining of metallic work pieces. Fluids manufactured with boric acid or boron-based additives effectively reduce friction, prevent galling and severe wear problems on cutting and forming tools.

  5. Electrorheological fluids and methods

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter F.; McIntyre, Ernest C.

    2015-06-02

    Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.

  6. The Fluids RAP

    Science.gov (United States)

    Nedyalkov, Ivaylo

    2016-11-01

    After fifteen years of experience in rap, and ten in fluid mechanics, "I am coming here with high-Reynolds-number stamina; I can beat these rap folks whose flows are... laminar." The rap relates fluid flows to rap flows. The fluid concepts presented in the song have varying complexity and the listeners/viewers will be encouraged to read the explanations on a site dedicated to the rap. The music video will provide an opportunity to share high-quality fluid visualizations with a general audience. This talk will present the rap lyrics, the vision for the video, and the strategy for outreach. Suggestions and comments will be welcomed.

  7. Theoretical Fluid Dynamics

    CERN Document Server

    Shivamoggi, Bhimsen K

    1998-01-01

    "Although there are many texts and monographs on fluid dynamics, I do not know of any which is as comprehensive as the present book. It surveys nearly the entire field of classical fluid dynamics in an advanced, compact, and clear manner, and discusses the various conceptual and analytical models of fluid flow." - Foundations of Physics on the first edition. Theoretical Fluid Dynamics functions equally well as a graduate-level text and a professional reference. Steering a middle course between the empiricism of engineering and the abstractions of pure mathematics, the author focuses

  8. Fluid dynamics transactions

    CERN Document Server

    Fiszdon, W

    1965-01-01

    Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co

  9. Electrodynamics of a Cosmic Dark Fluid

    Directory of Open Access Journals (Sweden)

    Alexander B. Balakin

    2016-06-01

    Full Text Available Cosmic Dark Fluid is considered as a non-stationary medium, in which electromagnetic waves propagate, and magneto-electric field structures emerge and evolve. A medium-type representation of the Dark Fluid allows us to involve in its analysis the concepts and mathematical formalism elaborated in the framework of classical covariant electrodynamics of continua, and to distinguish dark analogs of well-known medium-effects, such as optical activity, pyro-electricity, piezo-magnetism, electro- and magneto-striction and dynamo-optical activity. The Dark Fluid is assumed to be formed by a duet of a Dark Matter (a pseudoscalar axionic constituent and Dark Energy (a scalar element; respectively, we distinguish electrodynamic effects induced by these two constituents of the Dark Fluid. The review contains discussions of 10 models, which describe electrodynamic effects induced by Dark Matter and/or Dark Energy. The models are accompanied by examples of exact solutions to the master equations, correspondingly extended; applications are considered for cosmology and space-times with spherical and pp-wave symmetries. In these applications we focused the attention on three main electromagnetic phenomena induced by the Dark Fluid: first, emergence of Longitudinal Magneto-Electric Clusters; second, generation of anomalous electromagnetic responses; third, formation of Dark Epochs in the Universe history.

  10. Interfacial gauge methods for incompressible fluid dynamics.

    Science.gov (United States)

    Saye, Robert

    2016-06-01

    Designing numerical methods for incompressible fluid flow involving moving interfaces, for example, in the computational modeling of bubble dynamics, swimming organisms, or surface waves, presents challenges due to the coupling of interfacial forces with incompressibility constraints. A class of methods, denoted interfacial gauge methods, is introduced for computing solutions to the corresponding incompressible Navier-Stokes equations. These methods use a type of "gauge freedom" to reduce the numerical coupling between fluid velocity, pressure, and interface position, allowing high-order accurate numerical methods to be developed more easily. Making use of an implicit mesh discontinuous Galerkin framework, developed in tandem with this work, high-order results are demonstrated, including surface tension dynamics in which fluid velocity, pressure, and interface geometry are computed with fourth-order spatial accuracy in the maximum norm. Applications are demonstrated with two-phase fluid flow displaying fine-scaled capillary wave dynamics, rigid body fluid-structure interaction, and a fluid-jet free surface flow problem exhibiting vortex shedding induced by a type of Plateau-Rayleigh instability. The developed methods can be generalized to other types of interfacial flow and facilitate precise computation of complex fluid interface phenomena.

  11. Thermal Tides in Fluid Extrasolar Planets

    CERN Document Server

    Arras, Phil

    2009-01-01

    Asynchronous rotation and orbital eccentricity lead to time-dependent irradiation of the close-in gas giant exoplanets -- the hot Jupiters. This time-dependent surface heating gives rise to fluid motions which propagate throughout the planet. We investigate the ability of this "thermal tide" to produce a quadrupole moment which can couple to the stellar gravitational tidal force. While previous investigations discussed planets with solid surfaces, here we focus on entirely fluid planets in order to understand gas giants with small cores. The Coriolis force, thermal diffusion and self-gravity of the perturbations are ignored for simplicity. First, we examine the response to thermal forcing through analytic solutions of the fluid equations which treat the forcing frequency as a small parameter. In the "equilibrium tide" limit of zero frequency, fluid motion is present but does not induce a quadrupole moment. In the next approximation, finite frequency corrections to the equilibrium tide do lead to a nonzero qua...

  12. Absolute instability in viscoelastic mixing layers

    Science.gov (United States)

    Ray, Prasun K.; Zaki, Tamer A.

    2014-01-01

    The spatiotemporal linear stability of viscoelastic planar mixing layers is investigated. A one-parameter family of velocity profiles is used as the base state with the parameter, S, controlling the amount of shear and backflow. The influence of viscoelasticity in dilute polymer solutions is modeled with the Oldroyd-B and FENE-P constitutive equations. Both models require the specification of the ratio of the polymer-relaxation and convective time scales (the Weissenberg number, We) and the ratio of solvent and solution viscosities (β). The maximum polymer extensibility, L, must also be specified for the FENE-P model. We examine how the variation of these parameters along with the Reynolds number, Re, affects the minimum value of S at which the flow becomes locally absolutely unstable. With the Oldroyd-B model, the influence of viscoelasticity is shown to be almost fully captured by the elasticity, E^* equiv (1-β ) We/Re, and Scrit decreases as elasticity is increased, i.e., elasticity is destabilizing. A simple approximate dispersion relation obtained via long-wave asymptotic analysis is shown to accurately capture this destabilizing influence. Results obtained with the FENE-P model exhibit a rich variety of behavior. At large values of the extensibility, L, results are similar to those for the Oldroyd-B fluid as expected. However, when the extensibility is reduced to more realistic values (L ≈ 100), one must consider the scaled shear rate, η _c equiv We S/2L, in addition to the elasticity. When ηc is large, the base-state polymer stress obtained by the FENE-P model is reduced, and there is a corresponding reduction in the overall influence of viscoelasticity on stability. Additionally, elasticity exhibits a stabilizing effect which is driven by the streamwise-normal perturbation polymer stress. As ηc is reduced, the base-state and perturbation normal polymer stresses predicted by the FENE-P model move towards the Oldroyd-B values, and the destabilizing

  13. Space Station fluid management logistics

    Science.gov (United States)

    Dominick, Sam M.

    1990-01-01

    Viewgraphs and discussion on space station fluid management logistics are presented. Topics covered include: fluid management logistics - issues for Space Station Freedom evolution; current fluid logistics approach; evolution of Space Station Freedom fluid resupply; launch vehicle evolution; ELV logistics system approach; logistics carrier configuration; expendable fluid/propellant carrier description; fluid carrier design concept; logistics carrier orbital operations; carrier operations at space station; summary/status of orbital fluid transfer techniques; Soviet progress tanker system; and Soviet propellant resupply system observations.

  14. Dynamics of Complex Fluid-Fluid Interfaces

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2016-01-01

    This chapter presents an overview of recent progress in modelling the behaviour of complex fluid–fluid interfaces with non-equilibrium thermodynamics. We will limit ourselves to frameworks employing the Gibbs dividing surface model, and start with a general discussion of the surface excess variables

  15. Numerical modeling of bubble dynamics in viscoelastic media with relaxation

    Science.gov (United States)

    Warnez, M. T.; Johnsen, E.

    2015-06-01

    Cavitation occurs in a variety of non-Newtonian fluids and viscoelastic materials. The large-amplitude volumetric oscillations of cavitation bubbles give rise to high temperatures and pressures at collapse, as well as induce large and rapid deformation of the surroundings. In this work, we develop a comprehensive numerical framework for spherical bubble dynamics in isotropic media obeying a wide range of viscoelastic constitutive relationships. Our numerical approach solves the compressible Keller-Miksis equation with full thermal effects (inside and outside the bubble) when coupled to a highly generalized constitutive relationship (which allows Newtonian, Kelvin-Voigt, Zener, linear Maxwell, upper-convected Maxwell, Jeffreys, Oldroyd-B, Giesekus, and Phan-Thien-Tanner models). For the latter two models, partial differential equations (PDEs) must be solved in the surrounding medium; for the remaining models, we show that the PDEs can be reduced to ordinary differential equations. To solve the general constitutive PDEs, we present a Chebyshev spectral collocation method, which is robust even for violent collapse. Combining this numerical approach with theoretical analysis, we simulate bubble dynamics in various viscoelastic media to determine the impact of relaxation time, a constitutive parameter, on the associated physics. Relaxation time is found to increase bubble growth and permit rebounds driven purely by residual stresses in the surroundings. Different regimes of oscillations occur depending on the relaxation time.

  16. Modeling of Dynamic Fluid Forces in Fast Switching Valves

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik Clemmensen;

    2015-01-01

    Switching valves experience opposing fluid forces due to movement of the moving member itself, as the surrounding fluid volume must move to accommodate the movement. This movement-induced fluid force may be divided into three main components; the added mass term, the viscous term and the socalled...... history term. For general valve geometries there are no simple solution to either of these terms. During development and design of such switching valves, it is therefore, common practice to use simple models to describe the opposing fluid forces, neglecting all but the viscous term which is determined...... based on shearing areas and venting channels. For fast acting valves the opposing fluid force may retard the valve performance significantly, if appropriate measures are not taken during the valve design. Unsteady Computational Fluid Dynamics (CFD) simulations are available to simulate the total fluid...

  17. Controlled differential pressure system for an enhanced fluid blending apparatus

    Science.gov (United States)

    Hallman, Jr., Russell Louis

    2009-02-24

    A system and method for producing a controlled blend of two or more fluids. Thermally-induced permeation through a permeable tube is used to mix a first fluid from outside the tube with a second fluid flowing through the tube. Mixture ratios may be controlled by adjusting the temperature of the first fluid or by adjusting the pressure drop through the permeable tube. The combination of a back pressure control valve and a differential regulator is used to control the output pressure of the blended fluid. The combination of the back pressure control valve and differential regulator provides superior flow control of the second dry gas. A valve manifold system may be used to mix multiple fluids, and to adjust the volume of blended fluid produced, and to further modify the mixture ratio.

  18. Fluid loading responsiveness

    NARCIS (Netherlands)

    Geerts, Bart

    2011-01-01

    Patients in the intensive care unit (ICU) and in the peri-operative phase are dependent on physicians and nurses for their fluid intake. Volume status optimization is required to maximize oxygen delivery to vital organs. Unnecessary fluid administration can, however, lead to general and pulmonary

  19. Fluid loading responsiveness

    NARCIS (Netherlands)

    Geerts, Bart

    2011-01-01

    Patients in the intensive care unit (ICU) and in the peri-operative phase are dependent on physicians and nurses for their fluid intake. Volume status optimization is required to maximize oxygen delivery to vital organs. Unnecessary fluid administration can, however, lead to general and pulmonary oe

  20. Peritoneal fluid culture

    Science.gov (United States)

    Culture - peritoneal fluid ... sent to the laboratory for Gram stain and culture. The sample is checked to see if bacteria ... The peritoneal fluid culture may be negative, even if you have ... diagnosis of peritonitis is based on other factors, in addition ...

  1. Applications of fluid dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Round, G.R.; Garg, V.K.

    1986-01-01

    This book describes flexible and practical approach to learning the basics of fluid dynamics. Each chapter is a self-contained work session and includes a fluid dynamics concept, an explanation of the principles involved, an illustration of their application and references on where more detailed discussions can be found.

  2. Fluid loading responsiveness

    NARCIS (Netherlands)

    Geerts, Bart

    2011-01-01

    Patients in the intensive care unit (ICU) and in the peri-operative phase are dependent on physicians and nurses for their fluid intake. Volume status optimization is required to maximize oxygen delivery to vital organs. Unnecessary fluid administration can, however, lead to general and pulmonary oe

  3. Fluid blade disablement tool

    Energy Technology Data Exchange (ETDEWEB)

    Jakaboski, Juan-Carlos [Albuquerque, NM; Hughs, Chance G [Albuquerque, NM; Todd, Steven N [Rio Rancho, NM

    2012-01-10

    A fluid blade disablement (FBD) tool that forms both a focused fluid projectile that resembles a blade, which can provide precision penetration of a barrier wall, and a broad fluid projectile that functions substantially like a hammer, which can produce general disruption of structures behind the barrier wall. Embodiments of the FBD tool comprise a container capable of holding fluid, an explosive assembly which is positioned within the container and which comprises an explosive holder and explosive, and a means for detonating. The container has a concavity on the side adjacent to the exposed surface of the explosive. The position of the concavity relative to the explosive and its construction of materials with thicknesses that facilitate inversion and/or rupture of the concavity wall enable the formation of a sharp and coherent blade of fluid advancing ahead of the detonation gases.

  4. The Nonlinear Rheology of Electrorheological Fluids

    Science.gov (United States)

    Martin, James E.

    1998-03-01

    When a colloidal suspension is exposed to a uniaxial electric field the polarized particles chain along field lines causing a macroscopic "solidification" of the fluid, the basis of the so-called electrorheological (ER) effect. Likewise, in a rotating electric field particles form sheets in the plane of the field, which we call the rotary ER effect. Both of these fluids exhibit a nonlinear, shear thinning rheology, due to shear-induced structural relaxations. Because the fluid stress can be controlled by the applied field, a number of applications are possible, including electromechanical actuators, clutches, and active vibration dampers. To design these devices, and to develop effective control loop algorithms, it is necessary to understand the strongly nonlinear rheology of these fluids. We have used time-resolved, two-dimensional light scattering on a concentrated colloidal silica fluid in steady and oscillatory shear to demonstrate that the fragmentation and aggregation of chain-like particle microstructures is the cause of flow nonlinearities. We show that the light scattering is an indirect measure of the fluid stress. These observations form the basis of a kinetic chain model we developed to describe the nonlinear dynamics of the microstructures in ER fluids in nonstationary shear flows. Understanding the microstructural dynamics then leads us to a theory of the macroscopic rheology of these fluids in nonstationary, low Reynolds number flows. Finally, we have conducted extensive large-scale (1000-10000 particles) simulations of these fluids in steady and oscillatory shear, and will compare these results to theory and experiment.

  5. Amniotic fluid water dynamics.

    Science.gov (United States)

    Beall, M H; van den Wijngaard, J P H M; van Gemert, M J C; Ross, M G

    2007-01-01

    Water arrives in the mammalian gestation from the maternal circulation across the placenta. It then circulates between the fetal water compartments, including the fetal body compartments, the placenta and the amniotic fluid. Amniotic fluid is created by the flow of fluid from the fetal lung and bladder. A major pathway for amniotic fluid resorption is fetal swallowing; however in many cases the amounts of fluid produced and absorbed do not balance. A second resorption pathway, the intramembranous pathway (across the amnion to the fetal circulation), has been proposed to explain the maintenance of normal amniotic fluid volume. Amniotic fluid volume is thus a function both of the amount of water transferred to the gestation across the placental membrane, and the flux of water across the amnion. Membrane water flux is a function of the water permeability of the membrane; available data suggests that the amnion is the structure limiting intramembranous water flow. In the placenta, the syncytiotrophoblast is likely to be responsible for limiting water flow across the placenta. In human tissues, placental trophoblast membrane permeability increases with gestational age, suggesting a mechanism for the increased water flow necessary in late gestation. Membrane water flow can be driven by both hydrostatic and osmotic forces. Changes in both osmotic/oncotic and hydrostatic forces in the placenta my alter maternal-fetal water flow. A normal amniotic fluid volume is critical for normal fetal growth and development. The study of amniotic fluid volume regulation may yield important insights into the mechanisms used by the fetus to maintain water homeostasis. Knowledge of these mechanisms may allow novel treatments for amniotic fluid volume abnormalities with resultant improvement in clinical outcome.

  6. Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Ono, Shigeaki

    2012-01-01

    Subduction-zone magmatism is triggered by the addition of H2O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry. PMID:23112158

  7. Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism.

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Matsukage, Kyoko N; Ono, Shigeaki

    2012-11-13

    Subduction-zone magmatism is triggered by the addition of H(2)O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry.

  8. Micromachined Fluid Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Shiqiang Liu

    2017-02-01

    Full Text Available Micromachined fluid inertial sensors are an important class of inertial sensors, which mainly includes thermal accelerometers and fluid gyroscopes, which have now been developed since the end of the last century for about 20 years. Compared with conventional silicon or quartz inertial sensors, the fluid inertial sensors use a fluid instead of a solid proof mass as the moving and sensitive element, and thus offer advantages of simple structures, low cost, high shock resistance, and large measurement ranges while the sensitivity and bandwidth are not competitive. Many studies and various designs have been reported in the past two decades. This review firstly introduces the working principles of fluid inertial sensors, followed by the relevant research developments. The micromachined thermal accelerometers based on thermal convection have developed maturely and become commercialized. However, the micromachined fluid gyroscopes, which are based on jet flow or thermal flow, are less mature. The key issues and technologies of the thermal accelerometers, mainly including bandwidth, temperature compensation, monolithic integration of tri-axis accelerometers and strategies for high production yields are also summarized and discussed. For the micromachined fluid gyroscopes, improving integration and sensitivity, reducing thermal errors and cross coupling errors are the issues of most concern.

  9. FRACTURING FLUID CHARACTERIZATION FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Subhash Shah

    2000-08-01

    Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

  10. Applied fluid mechanics; Mecanique des fluides appliquee

    Energy Technology Data Exchange (ETDEWEB)

    Viollet, P.L.; Chabard, J.P.; Esposito, P.; Laurence, D. [Ecole Nationale des Ponts et Chaussees (ENPC), 75 - Paris (France)]|[Electricite de France (EDF), 75 - Paris (France). Direction des Etudes et Recherches

    2002-07-01

    Computational hydraulics, computational fluid dynamics, and hydro-informatics have invaded virtually all domains of research and application in hydro-science and fluids engineering. To the extent that this invasion has led to improved understanding of complex fluid phenomena and provided a frame of reference for testing and verifying designs and operational schemes, we have all benefited from it. But to the extent that it has shifted attention away from fundamental descriptions and understanding of fluid phenomena, and toward computational and numerical issues, this invasion has left avoid in the scientific and technical literature. This void exists somewhere between student exposure to first principles of solid and fluid mechanics on the one hand, and advanced-student and researcher/practitioner exposure to computational techniques and applications on the other. This new text naturally and refreshingly steps in to fill this void, and as such is a most welcome addition to the literature and to personal and institutional libraries. The text is refreshing in its innovative and careful attention to setting the historical framework of general and specific topics. This is most notable in the first chapter, which very gracefully and efficiently leads the reader through historical developments to contemporary mathematical statements of basic fluid phenomena. Once the authors have established this foundation of fundamental principles, they tie each succeeding chapter back into the introduction with appropriate and supportive historical contexts. Although the text does not shy away from rigorous analytical descriptions of fluid phenomena, it is unique in providing this delightful historical context for each topic. The authors have also made a special effort to tie the chapters together into a unified whole, with ample references forward and back; this is indeed rare, and much appreciated, in a text of multiple authorship. The topics treated and chapter structures reflect

  11. Guiding role of USCOM in fluid management of ARDS patients induced by pulmonary contusion%USCOM对肺挫伤致ARDS患者液体管理的指导作用

    Institute of Scientific and Technical Information of China (English)

    张伟强; 李玉著; 王晓芝; 姜海明; 王惠娟

    2014-01-01

    Objective To study the guiding role of ultrasonic cardiac output monitor (USCOM ) in fluid management of ARDS patients induced by pulmonary contusion .Methods A total of 30 ARDS patients induced by pulmonary contusion were random-ly divided into the experimental group and the control group (n=15 each) ,and the experimental group was given the fluid man-agement according to USCOM ,and the control group according to CVP .Liquid intake and output volumes after 24 ,48 and 72 h were calculated .Arterial blood lactic acid and oxygenation index were measured at 1th ,2th ,3th ,5th and 7th day .Patients were followed until time of hospital discharge to determine hours of mechanical ventilation ,hours of vasoactive agent support and 28 d mortality .Results There were no statistical difference in the liquid balance volume of intake and output between the two groups after 24 ,48 and 72 h .statistical difference was found in oxygenation index between the two groups at 5th day .Oxygena-tion index improved earlier in the USCOM group .Hours of mechanical ventilation of the USCOM group was significantly shor-ter than the patients'of the CVP group ,however ,there was no statistical difference between the two groups in hours of vasoac-tive agent support .Conclusions The fluid management using USCOM can earlier improve the oxygenation index and shorten duration of mechanical ventilation ,but can't significantly decrease the 28 d mortality rate of ARDS patients induced by pulmona-ry contusion .%目的:研究超声心输出量监测仪(USCOM )对肺挫伤致急性呼吸窘迫综合征(ARDS)患者的液体管理在临床工作中的指导作用。方法选取30例肺挫伤致 ARDS的患者作为研究对象,随机分为实验组和对照组各15例,实验组通过 US-COM监测指导患者的液体管理,对照组通过监测中心静脉压(CVP)指导液体管理,比较两组患者入住ICU后24、48、72 h的液体出入量,第1、2、3、5、7天的动脉血乳

  12. Fundamentals of fluid lubrication

    Science.gov (United States)

    Hamrock, Bernard J.

    1991-01-01

    The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.

  13. Physics of Fluids

    OpenAIRE

    2007-01-01

    Periodic motion of three stirrers in a two-dimensional flow can lead to chaotic transport of the surrounding fluid. For certain stirrer motions, the generation of chaos is guaranteed solely by the topology of that motion and continuity of the fluid. Work in this area has focused largely on using physical rods as stirrers, but the theory also applies when the "stirrers" are passive fluid particles. We demonstrate the occurrence of topological chaos for Stokes flow in a two-dimensional lid-driv...

  14. Supercritical fluid extraction

    Science.gov (United States)

    Wai, Chien M.; Laintz, Kenneth

    1994-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  15. Geophysical fluid flow experiment

    Science.gov (United States)

    Broome, B. G.; Fichtl, G.; Fowlis, W.

    1979-01-01

    The essential fluid flow processes associated with the solar and Jovian atmospheres will be examined in a laboratory experiment scheduled for performance on Spacelab Missions One and Three. The experimental instrumentation required to generate and to record convective fluid flow is described. Details of the optical system configuration, the lens design, and the optical coatings are described. Measurement of thermal gradient fields by schlieren techniques and measurement of fluid flow velocity fields by photochromic dye tracers is achieved with a common optical system which utilizes photographic film for data recording. Generation of the photochromic dye tracers is described, and data annotation of experimental parameters on the film record is discussed.

  16. Synthetic Base Fluids

    Science.gov (United States)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  17. Simulation of Fluid-Structure and Fluid-Mediated Structure-Structure Interactions in Stokes Regime Using Immersed Boundary Method

    Directory of Open Access Journals (Sweden)

    Masoud Baghalnezhad

    2014-01-01

    Full Text Available The Stokes flow induced by the motion of an elastic massless filament immersed in a two-dimensional fluid is studied. Initially, the filament is deviated from its equilibrium state and the fluid is at rest. The filament will induce fluid motion while returning to its equilibrium state. Two different test cases are examined. In both cases, the motion of a fixed-end massless filament induces the fluid motion inside a square domain. However, in the second test case, a deformable circular string is placed in the square domain and its interaction with the Stokes flow induced by the filament motion is studied. The interaction between the fluid and deformable body/bodies can become very complicated from the computational point of view. An immersed boundary method is used in the present study. In order to substantiate the accuracy of the numerical method employed, the simulated results associated with the Stokes flow induced by the motion of an extending star string are compared well with those obtained by the immersed interface method. The results show the ability and accuracy of the IBM method in solving the complicated fluid-structure and fluid-mediated structure-structure interaction problems happening in a wide variety of engineering and biological systems.

  18. Peritoneal Fluid Analysis

    Science.gov (United States)

    ... Peritoneal fluid glucose, amylase, tumor markers, bilirubin, creatinine, lactate dehydrogenase (LD) Microscopic examination – may be performed if infection or cancer is suspected; a laboratory professional may use a ...

  19. Culture - joint fluid

    Science.gov (United States)

    Joint fluid culture ... fungi, or viruses grow. This is called a culture. If these germs are detected, other tests may ... is no special preparation needed for the lab culture. How to prepare for the removal of joint ...

  20. Pericardial fluid culture

    Science.gov (United States)

    ... the thin sac that surrounds the heart (the pericardium). A small amount of fluid is removed. You ... may be due to an infection of the pericardium. The specific organism causing the infection may be ...

  1. Polymer Fluid Dynamics.

    Science.gov (United States)

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  2. Nonpolluting drilling fluid composition

    Energy Technology Data Exchange (ETDEWEB)

    Larson, D.E.; Mocek, C.J.; Mouton, R.J.

    1983-02-22

    Disclosed is a nonpolluting drilling fluid composition. The composition mixture consisting essentially of a concentrate and any nonpolluting oil. The concentrate consists essentially of diethanolamide, a fatty acid, and a imidazoline/amide mixture.

  3. Cerebrospinal fluid (CSF) culture

    Science.gov (United States)

    ... is a laboratory test to look for bacteria, fungi, and viruses in the fluid that moves in ... culture medium. Laboratory staff then observe if bacteria, fungi, or viruses grow in the dish. Growth means ...

  4. Offshore Structural Control Considering Fluid Structure Interaction

    Institute of Scientific and Technical Information of China (English)

    Ju Myung KIM; Dong Hyawn KIM; Gyu Won LEE

    2006-01-01

    Tuned Mass Damper (TMD) was applied to an offshore structure to control ocean wave-induced vibration. In the analysis of the dynamic response of the offshore structure, fluid-structure interaction is considered and the errors, which occur in the linearization of the interaction, are investigated. For the investigation of the performance of TMD in controlling the vibration, both regular waves with different periods and irregular waves with different significant wave heights are used. Based on the numerical analysis it is concluded that the fluid-structure interaction should be considered in the evaluation of the capability of TMD in vibration control of offshore structures.

  5. [Diagnosis: synovial fluid analysis].

    Science.gov (United States)

    Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente

    2014-01-01

    Synovial fluid analysis in rheumatological diseases allows a more accurate diagnosis in some entities, mainly infectious and microcrystalline arthritis. Examination of synovial fluid in patients with osteoarthritis is useful if a differential diagnosis will be performed with other processes and to distinguish between inflammatory and non-inflammatory forms. Joint aspiration is a diagnostic and sometimes therapeutic procedure that is available to primary care physicians. Copyright © 2014 Elsevier España, S.L. All rights reserved.

  6. Conventional cerebrospinal fluid scanning

    Energy Technology Data Exchange (ETDEWEB)

    Schicha, H.

    1985-06-01

    Conventional cerebrospinal fluid scanning (CSF scanning) today is mainly carried out in addition to computerized tomography to obtain information about liquor flow kinetics. Especially in patients with communicating obstructive hydrocephalus, CSF scanning is clinically useful for the decision for shunt surgery. In patients with intracranial cysts, CSF scanning can provide information about liquor circulation. Further indications for CSF scanning include the assessment of shunt patency especially in children, as well as the detection and localization of cerebrospinal fluid leaks.

  7. CARACTERÍSTICAS FÍSICO-QUÍMICAS E CITOLÓGICAS DO LÍQUIDO SINOVIAL DE PÔNEIS COM MODELO DE SINOVITE INDUZIDA PHYSICAL, BIOCHEMICAL AND CYTOLOGICAL CHARACTERISTICS OF SYNOVIAL FLUID WITH INDUCED SYNOVITIS MODEL IN PONIES

    Directory of Open Access Journals (Sweden)

    Ricardo Pozzobon

    2009-12-01

    Full Text Available

    O objetivo deste estudo foi descrever as principais alterações do líquido sinovial de seis pôneis com sinovite induzida através da administração intra-articular de 0,5 mL de adjuvante completo de Freund. As características físico-químicas e citológicas foram avaliadas antes da indução da sinovite (T0, cinco dias pós-indução (T1 e, a partir daí, às 12 (T2, 24 (T3, 48 (T4, 72 (T5, 96 (T6 e 120 horas (T7. A articulação contralateral sadia serviu como controle. A proteína, a viscosidade e a qualidade da precipitação da mucina não diferiram (P>0,05 entre as articulações em T0. Em T1, o líquido sinovial das articulações com sinovite apresentou aumento da concentração de proteína (6,5 g/dl, baixa viscosidade e baixa qualidade do precipitado da mucina, resultados que permaneceram estáveis até T7. Nas articulações sadias não foi observada diferença na viscosidade e qualidade da mucina até o final do experimento, mas, devido às artrocenteses, a proteína aumentou (p<0,05 em T6 e T7. Nas articulações induzidas houve aumento acentuado (p<0,05 de células nucleadas (>700 células/mm3 em T1, com decréscimo em T3, mas permanecendo em níveis considerados inflamatórios durante todo tempo de observação. A contagem diferencial revelou predominância de neutrófilos e presença de células mesoteliais reativas. A infiltração intra-articular com 0,5 mL de adjuvante completo de Freund produz uma sinovite neutrofílica de intensidade moderada a grave, semelhante à sinovite de ocorrência natural, reforçando a eficácia desse modelo para o estudo da patofisiologia e tratamento de doenças articulares.

    PALAVRAS-CHAVES: Articulação, equino, líquido sinovial, sinovite.

    The aim of this study was to describe the changes of the synovial fluid caused by experimental synovitis induced by an intra-articular injection of 0.5 mL of Freund’s complete adjuvant in six adult

  8. Fullerol ionic fluids

    KAUST Repository

    Fernandes, Nikhil

    2010-01-01

    We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like). © 2010 The Royal Society of Chemistry.

  9. The Tibetan singing bowl : an acoustics and fluid dynamics investigation

    CERN Document Server

    Terwagne, Denis

    2011-01-01

    We present the results of an experimental investigation of the acoustics and fluid dynamics of Tibetan singing bowls. Their acoustic behavior is rationalized in terms of the related dynamics of standing bells and wine glasses. Striking or rubbing a fluid-filled bowl excites wall vibrations, and concomitant waves at the fluid surface. Acoustic excitation of the bowl's natural vibrational modes allows for a controlled study in which the evolution of the surface waves with increasing forcing amplitude is detailed. Particular attention is given to rationalizing the observed criteria for the onset of edge-induced Faraday waves and droplet generation via surface fracture. Our study indicates that drops may be levitated on the fluid surface, induced to bounce on or skip across the vibrating fluid surface.

  10. Viscous Flow with Large Fluid-Fluid Interface Displacement

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Hassager, Ole; Saasen, Arild

    1998-01-01

    The arbitrary Lagrange-Euler (ALE) kinematic description has been implemented in a 3D transient finite element program to simulate multiple fluid flows with fluid-fluid interface or surface displacements. The description of fluid interfaces includes variable interfacial tension, and the formulation...

  11. Simulation Of The Synovial Fluid In A Deformable Cavity

    Science.gov (United States)

    Martinez-Gutierrez, Nancy; Ibarra-Bracamontes, Laura A.

    2016-11-01

    The main components of a synovial joint are a cartilage and a biofluid known as the synovial fluid. The results were obtained using the FLUENT software to simulate the behavior of the synovial fluid within a deformable cavity with a simple geometry. The cartilage is represented as a porous region. By reducing the available region for the fluid, a fluid displacement into the cartilage is induced. The total pressure reached in the interface of the deformable cavity and the porous region is presented. The geometry and properties of the system are scaled to values found in a knee joint. The effect of deformation rate, fluid viscosity and properties of the porous medium on the total pressure reached are analyzed. The higher pressures are reached either for high deformation rate or when the fluid viscosity increases. This study was supported by the Mexican Council of Science and Technology (CONACyT) and by the Scientific Research Coordination of the University of Michoacan in Mexico.

  12. Zero-G fluid mechanics in animal and man

    Science.gov (United States)

    Sandler, H.

    1986-01-01

    Significant cardiovascular change occurs with spaceflight. Loss of normal hydrostatic pressure gradients (head-to-foot), present while upright on earth, results in significant headward fluid shift of vascular and interstitial fluids. The resultant fluid change also shifts the hydrostatic indifference point for the circulation. The persistent distention of neck veins and change in upper body tissue compliance initiates steps to adapt to and compensate for the sensed excess fluid. These result in a loss of intravascular volume through neuro-humoral mechanisms and the presence of a smaller heart size, leading to a state where the subject has a reduced adaptive capacity to stress, particularly to fluid shifts to the lower body as occurs when once again returning to earth. This article reviews what is known about the weightlessness-induced headward fluid shift and its effects on cardiovascular function.

  13. Two-phase cooling fluids; Les fluides frigoporteurs diphasiques

    Energy Technology Data Exchange (ETDEWEB)

    Lallemand, A. [Institut National des Sciences Appliquees (INSA), 69 - Lyon (France)

    1997-12-31

    In the framework of the diminution of heat transfer fluid consumption, the concept of indirect refrigerating circuits, using cooling intermediate fluids, is reviewed and the fluids that are currently used in these systems are described. Two-phase cooling fluids advantages over single-phase fluids are presented with their thermophysical characteristics: solid fraction, two-phase mixture enthalpy, thermal and rheological properties, determination of heat and mass transfer characteristics, and cold storage through ice slurry

  14. Chemically driven fluid transport in long microchannels

    Science.gov (United States)

    Shen, Mingren; Ye, Fangfu; Liu, Rui; Chen, Ke; Yang, Mingcheng; Ripoll, Marisol

    2016-09-01

    Chemical gradients maintained along surfaces can drive fluid flows by diffusio-osmosis, which become significant at micro- and nano-scales. Here, by means of mesoscopic simulations, we show that a concentration drop across microchannels with periodically inhomogeneous boundary walls can laterally transport fluids over arbitrarily long distances along the microchannel. The driving field is the secondary local chemical gradient parallel to the channel induced by the periodic inhomogeneity of the channel wall. The flow velocity depends on the concentration drop across the channel and the structure and composition of the channel walls, but it is independent of the overall channel length. Our work thus presents new insight into the fluid transport in long microchannels commonly found in nature and is useful for designing novel micro- or nano-fluidic pumps.

  15. Convective heat transport in compressible fluids.

    Science.gov (United States)

    Furukawa, Akira; Onuki, Akira

    2002-07-01

    We present hydrodynamic equations of compressible fluids in gravity as a generalization of those in the Boussinesq approximation used for nearly incompressible fluids. They account for adiabatic processes taking place throughout the cell (the piston effect) and those taking place within plumes (the adiabatic temperature gradient effect). Performing two-dimensional numerical analysis, we reveal some unique features of plume generation and convection in transient and steady states of compressible fluids. As the critical point is approached, the overall temperature changes induced by plume arrivals at the boundary walls are amplified, giving rise to overshoot behavior in transient states and significant noise in the temperature in steady states. The velocity field is suggested to assume a logarithmic profile within boundary layers. Random reversal of macroscopic shear flow is examined in a cell with unit aspect ratio. We also present a simple scaling theory for moderate Rayleigh numbers.

  16. Rossby waves with linear topography in barotropic fluids

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Rossby waves are the most important waves in the atmosphere and ocean, and are parts of a large-scale system in fluid. The theory and observation show that, they satisfy quasi-geostrophic and quasi-static equilibrium approximations. In this paper, solitary Rossby waves induced by linear topography in barotropic fluids with a shear flow are studied. In order to simplify the problem, the topography is taken as a linear function of latitude variable y, then employing a weakly nonlinear method and a perturbation method, a KdV (Korteweg-de Vries) equation describing evolution of the amplitude of solitary Rossby waves induced by linear topography is derived. The results show that the variation of linear topography can induce the solitary Rossby waves in barotropic fluids with a shear flow, and extend the classical geophysical theory of fluid dynamics.

  17. 孔板对载流管道中流致振动的影响分析%Study on Flow-Induced Vibration in Pipe Conveying Fluid with Orifice Plate

    Institute of Scientific and Technical Information of China (English)

    刘向红; 罗毓珊; 王海军

    2013-01-01

    Taking the vibration and noise in Reactor Cavity and Spent Fuel Pit Cooling and Treatment pipe line in nuclear power plant as an example,based on the actual experimental engineering parameters,the experimental studies on fluctuating pressure excitation and pipe vibration resulted from flow disturbance induced by single local resistance element-orifice plate are conducted under the condition of the different flow rate and the same back pressure.The pipe flow field and pressure field is numerically simulated,especially the flow station of orifice plate.The simulation results and experimental data are compared and analyzed.The research results show that the energy spectrum increases with the increasing of the degree of throttle of orifice plate.As the increasing of flow rate and fluid disturbance,the spectrum breadth of pressure fluctuate increases without the disturbance of other excitation source.%以核电厂反应堆和乏燃料水池冷却和处理系统(PTR)传水管后管线所产生的振动问题为背景,根据工程实际参数,在不同流量、背压相同条件下,开展孔板单个局部阻力件诱发流体扰动产生的脉动压力激励和管道振动的试验.对管线的流场和压力场进行数值模拟,尤其是孔板的流动状况,并将模拟计算结果与试验结果进行分析比较.研究认为,随孔板节流度的增大,能谱增大.在没有其他激励源干扰的条件下,随流量增大,流体扰动增强,压力脉动的谱幅值增大.

  18. Boiler using combustible fluid

    Science.gov (United States)

    Baumgartner, H.; Meier, J.G.

    1974-07-03

    A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

  19. Amniotic fluid embolism

    Directory of Open Access Journals (Sweden)

    Kiranpreet Kaur

    2016-01-01

    Full Text Available Amniotic fluid embolism (AFE is one of the catastrophic complications of pregnancy in which amniotic fluid, fetal cells, hair, or other debris enters into the maternal pulmonary circulation, causing cardiovascular collapse. Etiology largely remains unknown, but may occur in healthy women during labour, during cesarean section, after abnormal vaginal delivery, or during the second trimester of pregnancy. It may also occur up to 48 hours post-delivery. It can also occur during abortion, after abdominal trauma, and during amnio-infusion. The pathophysiology of AFE is not completely understood. Possible historical cause is that any breach of the barrier between maternal blood and amniotic fluid forces the entry of amniotic fluid into the systemic circulation and results in a physical obstruction of the pulmonary circulation. The presenting signs and symptoms of AFE involve many organ systems. Clinical signs and symptoms are acute dyspnea, cough, hypotension, cyanosis, fetal bradycardia, encephalopathy, acute pulmonary hypertension, coagulopathy etc. Besides basic investigations lung scan, serum tryptase levels, serum levels of C3 and C4 complements, zinc coproporphyrin, serum sialyl Tn etc are helpful in establishing the diagnosis. Treatment is mainly supportive, but exchange transfusion, extracorporeal membrane oxygenation, and uterine artery embolization have been tried from time to time. The maternal prognosis after amniotic fluid embolism is very poor though infant survival rate is around 70%.

  20. Stochastic interpenetration of fluids

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, M.J.; Clark, T.T.; Harlow, F.H.

    1995-11-01

    We describe a spectral approach to the investigation of fluid instability, generalized turbulence, and the interpenetration of fluids across an interface. The technique also applies to a single fluid with large variations in density. Departures of fluctuating velocity components from the local mean are far subsonic, but the mean Mach number can be large. Validity of the description is demonstrated by comparisons with experiments on turbulent mixing due to the late stages of Rayleigh-Taylor instability, when the dynamics become approximately self-similar in response to a constant body force. Generic forms for anisotropic spectral structure are described and used as a basis for deriving spectrally integrated moment equations that can be incorporated into computer codes for scientific and engineering analyses.

  1. Vorticity in holographic fluids

    CERN Document Server

    Caldarelli, Marco M; Petkou, Anastasios C; Petropoulos, P Marios; Pozzoli, Valentina; Siampos, Konstadinos

    2012-01-01

    In view of the recent interest in reproducing holographically various properties of conformal fluids, we review the issue of vorticity in the context of AdS/CFT. Three-dimensional fluids with vorticity require four-dimensional bulk geometries with either angular momentum or nut charge, whose boundary geometries fall into the Papapetrou--Randers class. The boundary fluids emerge in stationary non-dissipative kinematic configurations, which can be cyclonic or vortex flows, evolving in compact or non-compact supports. A rich network of Einstein's solutions arises, naturally connected with three-dimensional Bianchi spaces. We use Fefferman--Graham expansion to handle holographic data from the bulk and discuss the alternative for reversing the process and reconstruct the exact bulk geometries.

  2. Seismicity and faulting attributable to fluid extraction

    Science.gov (United States)

    Yerkes, R.F.; Castle, R.O.

    1976-01-01

    The association between fluid injection and seismicity has been well documented and widely publicized. Less well known, but probably equally widespread are faulting and shallow seismicity attributable solely to fluid extraction, particularly in association with petroleum production. Two unequivocable examples of seismicity and faulting associated with fluid extraction in the United States are: The Goose Creek, Texas oil field event of 1925 (involving surface rupture); and the Wilmington, California oil field events (involving subsurface rupture) of 1947, 1949, 1951 (2), 1955, and 1961. Six additional cases of intensity I-VII earthquakes (M oil and gas fields. In addition to these examples are thirteen cases of apparently aseismic surface rupture associated with production from California and Texas oil fields. Small earthquakes in the Eloy-Picacho area of Arizona may be attributable to withdrawal of groundwater, but their relation to widespread fissuring is enigmatic. The clearest example of extraction-induced seismicity outside of North America is the 1951 series of earthquakes associated with gas production from the Po River delta near Caviga, Italy. Faulting and seismicity associated with fluid extraction are attributed to differential compaction at depth caused by reduction of reservoir fluid pressure and attendant increase in effective stress. Surface and subsurface measurements and theoretical and model studies show that differential compaction leads not only to differential subsidence and centripetally-directed horizontal displacements, but to changes in both vertical- and horizontal-strain regimes. Study of well-documented examples indicates that the occurrence and nature of faulting and seismicity associated with compaction are functions chiefly of: (1) the pre-exploitation strain regime, and (2) the magnitude of contractional horizontal strain centered over the compacting materials relative to that of the surrounding annulus of extensional horizontal

  3. Computational fluid dynamics

    CERN Document Server

    Magoules, Frederic

    2011-01-01

    Exploring new variations of classical methods as well as recent approaches appearing in the field, Computational Fluid Dynamics demonstrates the extensive use of numerical techniques and mathematical models in fluid mechanics. It presents various numerical methods, including finite volume, finite difference, finite element, spectral, smoothed particle hydrodynamics (SPH), mixed-element-volume, and free surface flow.Taking a unified point of view, the book first introduces the basis of finite volume, weighted residual, and spectral approaches. The contributors present the SPH method, a novel ap

  4. Fluids in cosmology

    CERN Document Server

    Cervantes-Cota, Jorge L

    2014-01-01

    We review the role of fluids in cosmology by first introducing them in General Relativity and then applied to a FRW Universe's model. We describe how relativistic and non-relativistic components evolve in the background dynamics. We also introduce scalar fields to show that they are able to yield an inflationary dynamics at very early times (inflation) and late times (quintessence). Then, we proceed to study the thermodynamical properties of the fluids and, lastly, its perturbed kinematics. We make emphasis in the constrictions of parameters by recent cosmological probes.

  5. Computational fluid dynamics

    CERN Document Server

    Blazek, Jiri

    2015-01-01

    Computational Fluid Dynamics: Principles and Applications, Third Edition presents students, engineers, and scientists with all they need to gain a solid understanding of the numerical methods and principles underlying modern computation techniques in fluid dynamics. By providing complete coverage of the essential knowledge required in order to write codes or understand commercial codes, the book gives the reader an overview of fundamentals and solution strategies in the early chapters before moving on to cover the details of different solution techniques. This updated edition includes new

  6. Attenuated Escherichia coli strains expressing the colonization factor antigen I (CFA/I) and a detoxified heat-labile enterotoxin (LThK63) enhance clearance of ETEC from the lungs of mice and protect mice from intestinal ETEC colonization and LT-induced fluid accumulation.

    Science.gov (United States)

    Byrd, Wyatt; Boedeker, Edgar C

    2013-03-15

    Although enterotoxigenic Escherichia coli (ETEC) infections are important causes of infantile and traveler's diarrhea there is no licensed vaccine available for those at-risk. Our goal is to develop a safe, live attenuated ETEC vaccine. We used an attenuated E. coli strain (O157:H7, Δ-intimin, Stx1-neg, Stx2-neg) as a vector (ZCR533) to prepare two vaccine strains, one strain expressing colonization factor antigen I (ZCR533-CFA/I) and one strain expressing CFA/I and a detoxified heat-labile enterotoxin (ZCR533-CFA/I+LThK63) to deliver ETEC antigens to mucosal sites in BALB/c mice. Following intranasal and intragastric immunization with the vaccine strains, serum IgG and IgA antibodies were measured to the CFA/I antigen, however, only serum IgG antibodies were detected to the heat-labile enterotoxin. Intranasal administration of the vaccine strains induced respiratory and intestinal antibody responses to the CFA/I and LT antigens, while intragastric administration induced only intestinal antibody responses with no respiratory antibodies detected to the CFA/I and LT antigens. Mice immunized intranasally with the vaccine strains showed enhanced clearance of wild-type (wt) ETEC bacteria from the lungs. Mice immunized intranasally and intragastrically with the vaccine strains were protected from intestinal colonization following oral challenge with ETEC wt bacteria. Mice immunized intragastrically with the ZCR533-CFA/I+LThK63 vaccine strain had less fluid accumulate in their intestine following challenge with ETEC wt bacteria or with purified LT as compared to the sham mice indicating that the immunized mice were protected from LT-induced intestinal fluid accumulation. Thus, mice intragastrically immunized with the ZCR533-CFA/I+LThK63 vaccine strain were able to effectively neutralize the activity of the LT enterotoxin. However, no difference in intestinal fluid accumulation was detected in the mice immunized intranasally with the vaccine strain as compared to the sham

  7. Multiphase fluid hammer: modeling, experiments and simulations

    OpenAIRE

    Lema Rodríguez, Marcos

    2013-01-01

    This thesis deals with the experimental and numerical analysis of the water hammer phenomenon generated by the discharge of a pressurized liquid into a pipeline kept under vacuum conditions. This flow configuration induces several multiphase phenomena such as cavitation and gas desorption that cannot be ignored in the water hammer behavior.The motivation of this research work comes from the liquid propulsion systems used in spacecrafts, which can undergo fluid hammer effects threatening the s...

  8. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of o

  9. Proteomics of body fluids

    NARCIS (Netherlands)

    L.J.M. Dekker (Lennard)

    2007-01-01

    textabstractIn this thesis we present newly developed methods for biomarker discovery. We applied these methods to discover biomarkers of leptomeningeal metastasis (LM) in the cerebrospinal fluid (CSF) from breast cancer patients and in serum from patients with prostate cancer. Early diagnos

  10. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of

  11. Orbital Fluid Resupply Assessment

    Science.gov (United States)

    Eberhardt, Ralph N.

    1989-01-01

    Orbital fluid resupply can significantly increase the cost-effectiveness and operational flexibility of spacecraft, satellites, and orbiting platforms and observatories. Reusable tankers are currently being designed for transporting fluids to space. A number of options exist for transporting the fluids and propellant to the space-based user systems. The fluids can be transported to space either in the Shuttle cargo bay or using expendable launch vehicles (ELVs). Resupply can thus be accomplished either from the Shuttle bay, or the tanker can be removed from the Shuttle bay or launched on an ELV and attached to a carrier such as the Orbital Maneuvering Vehicle (OMV) or Orbital Transfer Vehicle (OTV) for transport to the user to be serviced. A third option involves locating the tanker at the space station or an unmanned platform as a quasi-permanent servicing facility or depot which returns to the ground for recycling once its tanks are depleted. Current modular tanker designs for monopropellants, bipropellants, and water for space station propulsion are discussed. Superfluid helium tankers are addressed, including trade-offs in tanker sizes, shapes to fit the range of ELVs currently available, and boil-off losses associated with longer-term (greater than 6-month) space-basing. It is concluded that the mixed fleet approach to on-orbit consumables resupply offers significant advantages to the overall logistics requirements.

  12. Fluid resuscitation in trauma

    Directory of Open Access Journals (Sweden)

    Rudra A

    2006-01-01

    Full Text Available Appropriate fluid replacement is an essential component of trauma fluid resuscitation. Once hemorrhage is controlled, restoration of normovolemia is a priority. In the presence of uncontrolled haemorrhage, aggressive fluid management may be harmful. The crystalloid-colloid debate continues but existing clinical practice is more likely to reflect local biases rather than evidence based medicine. Colloids vary substantially in their pharmacology and pharmacokinetics,and the experimental finding based on one colloid cannot be extrapolated reliably to another. In the initial stages of trauma resuscitation the precise fluid used is probably not important as long as an appropriate volume is given. Later, when the microcirculation is ′leaky′, there may be some advantages to high or medium weight colloids such as hydroxyethyl starch. Hypertonic saline solutions may have some benefit in patients with head injuries. A number of hemoglobin solutions are under development, but one of the most promising of these has been withdrawn recently. It is highly likely that at least one of these solutions will eventually become routine therapy for trauma patient resuscitation. In the meantime, contrary to traditional teaching, recent data suggest that restrictive strategy of red cell transfusion may improve outcome in some critically ill patients.

  13. Amniotic Fluid Embolism

    Science.gov (United States)

    ... embolisms are rare, which makes it difficult to identify risk factors. It's estimated that there are between 1 ... Kramer MS, et al. Amniotic fluid embolism: Incidence, risk factors, and impact on perinatal outcome. BJOG: An International Journal of Obstetrics and Gynaecology. 2012;119:874. Baskett ...

  14. Relativistic viscoelastic fluid mechanics.

    Science.gov (United States)

    Fukuma, Masafumi; Sakatani, Yuho

    2011-08-01

    A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

  15. A high-order Immersed Boundary method for the simulation of polymeric flow

    Science.gov (United States)

    Stein, David; Thomases, Becca; Guy, Robert

    2016-11-01

    We present a robust, flexible, and high-order Immersed Boundary method for simulating fluid flow, including the Incompressible Navier-Stokes equations and certain models of viscoelastic flow, e.g. the Stokes-Oldroyd-B equations. The solution to the PDE is coupled with an equation for a smooth extension of the unknown solution; high-order accuracy is a natural consequence of this additional global regularity. Low and zero Reynolds number problems are handled efficiently and accurately. We demonstrate pointwise convergence of the polymeric stress for flows in complex domains, in contrast to the standard Immersed Boundary method, which generates large errors in the polymeric stress near to the boundaries.

  16. Local fluid transport by planktonic swarms

    Science.gov (United States)

    Martinez-Ortiz, Monica; Dabiri, John

    2013-11-01

    Energy transport in the ocean occurs through an intricate set of pathways mainly powered by physical phenomena. The hypothesis that vertical migrations of aquatic fauna may contribute to this process through the action of the induced drift mechanism has been investigated in recent years. Microscale measurements by Kunze et al. (1), in Saanich Inlet have shown the presence of high kinetic energy dissipation rates in the vicinity of vertically migrating krill swarms. However, it remains uncertain if energy is being introduced at scales large enough to induce the transport of fluid across surfaces of equal density. Within this context, the present study aims to provide experimental insight of fluid transport by planktonic swarms. The vertical migration of Artemia salina is triggered and controlled by means of a system of stationary and translating luminescent signals. High speed flow visualizations elucidate the competing effects of upward drift by the passive sections of the organisms and downward flow induced by the appendages. The resulting fluid transport is assessed by using PIV at different stages of the migration. The kinetic energy spectrum is computed using velocity correlation functions to determine the length scales at which the animals introduce energy to the flow.

  17. Characteristics of laminar MHD fluid hammer in pipe

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.Y.; Liu, Y.J., E-mail: yajun@scut.edu.cn

    2016-01-01

    As gradually wide applications of MHD fluid, transportation as well as control with pumps and valves is unavoidable, which induces MHD fluid hammer. The paper attempts to combine MHD effect and fluid hammer effect and to investigate the characteristics of laminar MHD fluid hammer. A non-dimensional fluid hammer model, based on Navier–Stocks equations, coupling with Lorentz force is numerically solved in a reservoir–pipe–valve system with uniform external magnetic field. The MHD effect is represented by the interaction number which associates with the conductivity of the MHD fluid as well as the external magnetic field and can be interpreted as the ratio of Lorentz force to Joukowsky force. The transient numerical results of pressure head, average velocity, wall shear stress, velocity profiles and shear stress profiles are provided. The additional MHD effect hinders fluid motion, weakens wave front and homogenizes velocity profiles, contributing to obvious attenuation of oscillation, strengthened line packing and weakened Richardson annular effect. Studying the characteristics of MHD laminar fluid hammer theoretically supplements the gap of knowledge of rapid-transient MHD flow and technically provides beneficial information for MHD pipeline system designers to better devise MHD systems. - Highlights: • Characteristics of laminar MHD fluid hammer are discussed by simulation. • MHD effect has significant influence on attenuation of wave. • MHD effect strengthens line packing. • MHD effect inhibits Richardson annular effect.

  18. Eclogites of the Dabie Region: Retrograde Metamorphism and Fluid Evolution

    Institute of Scientific and Technical Information of China (English)

    顾连兴; 杜建国; 翟建平; 赵成浩; 范建国; 张文兰

    2002-01-01

    Based upon fluid effects, retrograde metamorphism of eclogites in the Dabie region can be divided into the fluid-poor, fluid-bearing and fluid-rich stages. The fluid-poor stage is marked by polymorphic inversion, recrystallization and exsolution of solid solutions, and is thought to represent eclogite-facies retrograde environments. The fluid-bearing stage is likely to have occurred at the late stage of ecologite-facies diaphthorosis and is represented by kyanite porphyroblasts, rutile, and sodic pyroxene in association with high-pressure hydrous minerals such as phengite and zoisite (clinozoisite) without significant amount of hydrous minerals such as amphibole, epidote and biotite. The fluid-rich stage might have commenced concomitantly with lower amphibolite-facies diaphthoresis and persisted all the way towards the near-surface environment. The product of this stage is characterized by plentiful hydrous and volatile-bearing phases.The dissemination-type rutile mineralizations in eclogites might have formed by preferential shearing-induced pressure solution of gangue minerals at the fluid-bearing stage. The accompanying vein rutile was precipitated from fluids of this stage after local transport and concentration, and may hence represent proximal mobilization of titanium from the eclogite. Therefore, rutile veins can be used as an exploration indicator for dissemination-type rutile deposits.

  19. Fluid and sodium loss in whole-body-irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1987-09-01

    Whole-body and organ fluid compartment sizes and plasma sodium concentrations were measured in conventional, GI decontaminated, bile duct ligated, and choledochostomized rats at different times after various doses of gamma radiation. In addition, sodium excretion was measured in rats receiving lethal intestinal radiation injury. After doses which were sublethal for 3-5 day intestinal death, transient decreases occurred in all the fluid compartments measured (i.e., total body water, extracellular fluid space, plasma volume). No recovery of these fluid compartments was observed in rats destined to die from intestinal radiation injury. The magnitude of the decreases in fluid compartment sizes was dose dependent and correlated temporally with the breakdown and recovery of the intestinal mucosa but was independent of the presence or absence of enteric bacteria or bile acids. Associated with the loss of fluid was an excess excretion of 0.83 meq of sodium between 48 and 84 h postirradiation. This represents approximately 60% of the sodium lost from the extracellular fluid space in these animals during this time. The remaining extracellular sodium loss was due to redistribution of sodium to other spaces. It is concluded that radiation-induced breakdown of the intestinal mucosa results in lethal losses of fluid and sodium as evidenced by significant decreases in total body water, extracellular fluid space, plasma volume, and plasma sodium concentration, with hemoconcentration. These changes are sufficient to reduce tissue perfusion leading to irreversible hypovolemic shock and death.

  20. Structure-Enhanced Yield Shear Stress in Electrorheological Fluids

    Science.gov (United States)

    Tao, R.; Lan, Y. C.; Xu, X.

    A new technology, compression-assisted aggregation, is developed to enhance the strength of electrorheological (ER) fluids. The yield shear stress of ER fluids depends on the fluid microstructure. The unassisted electric-field induced ER structure mainly consists of single chains, whose weak points are at their ends. This new technology produces a structure consisting of robust thick columns with strong ends. As the weak points of the original ER structure are greatly enforced, the new structure makes ER fluids super-strong: At a moderate electric field and moderate pressure the yield shear stress of ER fluids at 35% volume fraction exceeds 100 kPa, well above any requirement for major industrial applications.

  1. Motions of elastic solids in fluids under vibration

    DEFF Research Database (Denmark)

    Sorokin, V. S.; Blekhman, I. I.; Thomsen, Jon Juel

    2010-01-01

    Motion of a rigid or deformable solid in a viscous incompressible fluid and corresponding fluid–solid interactions are considered. Different cases of applying high frequency vibrations to the solid or to the surrounding fluid are treated. Simple formulas for the mean velocity of the solid...... are derived, under the assumption that the regime of the fluid flow induced by its motion is turbulent and the fluid resistance force is nonlinearly dependent on its velocity. It is shown that vibrations of a fluid’s volume slow down the motion of a submerged solid. This effect is much pronounced in the case...... of a deformable solid (i.e., gas bubble) exposed to near-resonant excitation. The results are relevant to the theory of gravitational enrichment of raw materials, and also contribute to the theory of controlled locomotion of a body with an internal oscillator in continuous deformable (solid or fluid) media....

  2. Near-critical point phenomena in fluids (19-IML-1)

    Science.gov (United States)

    Beysens, D.

    1992-01-01

    Understanding the effects of gravity is essential if the behavior of fluids is to be predicted in spacecraft and orbital stations, and, more generally, to give a better understanding of the hydrodynamics in these systems. An understanding is sought of the behavior of fluids in space. What should emerge from the International Microgravity Lab (IML-1) mission is a better understanding of the kinetics of growth in off-critical conditions, in both liquid mixtures and pure fluids. This complex phenomenon is the object of intensive study in physics and materials sciences area. It is also expected that the IML-1 flight will procure key results to provide a better understanding of how a pure fluid can be homogenized without gravity induced convections, and to what extent the 'Piston Effect' is effective in thermalizing the compressible fluids.

  3. Free vibration of membrane/bounded incompressible fluid

    Institute of Scientific and Technical Information of China (English)

    S.TARIVERDILO; J.MIRZAPOUR; M.SHAHMARDANI; G.REZAZADEH

    2012-01-01

    Vibration of a circular membrane in contact with a fluid has extensive applications in industry.The natural vibration frequencies for the asymmetric free vibration of a circular membrane in contact with a bounded incompressible fluid are derived in this paper.Considering small oscillations induced by the membrane vibration in an incompressible and inviscid fluid,the velocity potential function is used to describe the fluid field.Two approaches are used to derive the free vibration frequencies of the system,which include a variational formulation and an approximate solution employing the Rayleigh quotient method.A good correlation is found between free vibration frequencies evaluated by these methods.Finally,the effects of the fluid depth,the mass density,and the radial tension on the free vibration frequencies of the coupled system are investigated.

  4. Experimental study on viscous fingering with partial miscible fluids

    Science.gov (United States)

    Suzuki, Ryuta; Nagatsu, Yuichiro; Mishra, Manoranjan; Ban, Takahiko

    2016-11-01

    Viscous fingering (VF) instability occurs when a more viscous fluid is displaced by a less viscous one in porous media or Hele-Shaw cells. So far, studies of VF have focused on fluids that are either fully miscible or immiscible. However, little attention has been paid to VF in partially miscible fluids. Here, we have experimentally investigated VF in a radial Hele-Shaw cell using an aqueous two phase system (Ban et al. Soft Matter, 2012) which is an example of partially miscible fluids system. We have found novel instabilities that are counter-intuitive in miscible and immiscible systems. These include multiple droplets formation for low flow rate and widening of fingers at intermediate flow rate. The occurrence of the new instability patterns is induced by Korteweg effect in which convection is induced during phase separation in partially miscible systems.

  5. Microgravity Fluids for Biology, Workshop

    Science.gov (United States)

    Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.

    2013-01-01

    Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.

  6. Tumor interstitial fluid

    DEFF Research Database (Denmark)

    Gromov, Pavel; Gromova, Irina; Olsen, Charlotta J.

    2013-01-01

    Tumor interstitial fluid (TIF) is a proximal fluid that, in addition to the set of blood soluble phase-borne proteins, holds a subset of aberrantly externalized components, mainly proteins, released by tumor cells and tumor microenvironment through various mechanisms, which include classical...... secretion, non-classical secretion, secretion via exosomes and membrane protein shedding. Consequently, the interstitial aqueous phase of solid tumors is a highly promising resource for the discovery of molecules associated with pathological changes in tissues. Firstly, it allows one to delve deeper...... into the regulatory mechanisms and functions of secretion-related processes in tumor development. Secondly, the anomalous secretion of molecules that is innate to tumors and the tumor microenvironment, being associated with cancer progression, offers a valuable source for biomarker discovery and possible targets...

  7. COUPLED CHEMOTAXIS FLUID MODEL

    KAUST Repository

    LORZ, ALEXANDER

    2010-06-01

    We consider a model system for the collective behavior of oxygen-driven swimming bacteria in an aquatic fluid. In certain parameter regimes, such suspensions of bacteria feature large-scale convection patterns as a result of the hydrodynamic interaction between bacteria. The presented model consist of a parabolicparabolic chemotaxis system for the oxygen concentration and the bacteria density coupled to an incompressible Stokes equation for the fluid driven by a gravitational force of the heavier bacteria. We show local existence of weak solutions in a bounded domain in d, d = 2, 3 with no-flux boundary condition and in 2 in the case of inhomogeneous Dirichlet conditions for the oxygen. © 2010 World Scientific Publishing Company.

  8. Galilean relativistic fluid mechanics

    CERN Document Server

    Ván, Péter

    2015-01-01

    Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...

  9. Zinc Determination in Pleural Fluid

    OpenAIRE

    Nazan DEMİR; DEMİR, Yaşar

    2000-01-01

    In this study, an enzymatic zinc determination method was applied to pleural fluid, the basis of which was the regaining of the activity of apo carbonic anhydrase by the zinc present in the sample. The method was used for pleural fluid zinc determination in order to show the application to body fluids other than serum. For this purpose, pleural fluids were obtained from 20 patients and zinc concentrations were determined. Carbonic anhydrase was purified by affinity chromatography from bovine ...

  10. Handbook of hydraulic fluid technology

    CERN Document Server

    Totten, George E

    2011-01-01

    ""The Handbook of Hydraulic Fluid Technology"" serves as the foremost resource for designing hydraulic systems and for selecting hydraulic fluids used in engineering applications. Featuring new illustrations, data tables, as well as practical examples, this second edition is updated with essential information on the latest hydraulic fluids and testing methods. The detailed text facilitates unparalleled understanding of the total hydraulic system, including important hardware, fluid properties, and hydraulic lubricants. Written by worldwide experts, the book also offers a rigorous overview of h

  11. Amniotic fluid embolism

    OpenAIRE

    Thongrong, Cattleya; Kasemsiri, Pornthep; Hofmann, James P; Bergese, Sergio D.; Thomas J Papadimos; Gracias, Vicente H.; Adolph, Michael D.; Stawicki, Stanislaw P A

    2013-01-01

    Amniotic fluid embolism (AFE) is an unpredictable and as-of-yet unpreventable complication of maternity. With its low incidence it is unlikely that any given practitioner will be confronted with a case of AFE. However, this rare occurrence carries a high probability of serious sequelae including cardiac arrest, ARDS, coagulopathy with massive hemorrhage, encephalopathy, seizures, and both maternal and infant mortality. In this review the current state of medical knowledge about AFE is outline...

  12. Galilean relativistic fluid mechanics

    OpenAIRE

    Ván, Péter

    2015-01-01

    Single component nonrelativistic dissipative fluids are treated independently of reference frames and flow-frames. First the basic fields and their balances, then the related thermodynamic relations and the entropy production are calculated and the linear constitutive relations are given. The usual basic fields of mass, momentum, energy and their current densities, the heat flux, pressure tensor and diffusion flux are the time- and spacelike components of the third order mass-momentum-energy ...

  13. Physics of Fluids

    OpenAIRE

    Luton, J. A.; Ragab, Saad A.

    1997-01-01

    The interaction of vortices passing near a solid surface has been examined using direct numerical simulation. The configuration studied is a counter-rotating vortex pair approaching a wall in an otherwise quiescent fluid. The focus of these simulations is on the three-dimensional effects, of which little is known. To the authors' knowledge, this is the first three-dimensional simulation that lends support to the short-wavelength instability of the secondary vortex. It has been shown how this ...

  14. Soluble oil cutting fluid

    Energy Technology Data Exchange (ETDEWEB)

    Rawlinson, A.P.; White, J.

    1987-06-23

    A soluble oil, suitable when diluted with water, for use as a cutting fluid comprises an alkali or alkaline-earth metal alkyl benzene sulphonate, a fatty acid diethanolamide, a mixed alkanolamine borate, a polyisobutenesuccinimide and a major proportion of mineral oil. The soluble oil is relatively stable without the need for a conventional coupling agent and some soluble oil emulsions are bio-static even though conventional biocides are not included.

  15. Fluid Dynamics and Viscosity in Strongly Correlated Fluids

    CERN Document Server

    Schaefer, Thomas

    2014-01-01

    We review the modern view of fluid dynamics as an effective low energy, long wavelength theory of many body systems at finite temperature. We introduce the notion of a nearly perfect fluid, defined by a ratio $\\eta/s$ of shear viscosity to entropy density of order $\\hbar/k_B$ or less. Nearly perfect fluids exhibit hydrodynamic behavior at all distances down to the microscopic length scale of the fluid. We summarize arguments that suggest that there is fundamental limit to fluidity, and review the current experimental situation with regard to measurements of $\\eta/s$ in strongly coupled quantum fluids.

  16. Magnetic resonance of magnetic fluid and magnetoliposome preparations

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Paulo C. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil)]. E-mail: pcmor@unb.br; Santos, Judes G. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil); Skeff Neto, K. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil); Pelegrini, Fernando [Universidade Federal de Goias, Instituto de Fisica, 74001-970 Goiania-GO (Brazil); Cuyper, Marcel de [Katholieke Universiteit Leuven, Campus Kortrijk, Interdisciplinary Research Centre, B-8500 Kortrijk (Belgium)

    2005-05-15

    In this study, magnetic resonance was used to investigate lauric acid-coated magnetite-based magnetic fluid particles and particles which are surrounded by a double layer of phospholipid molecules (magnetoliposomes). The data reveal the presence of monomers and dimers in both samples. Whereas evidence for a thermally induced disruption of dimers is found in the magnetic fluid, apparently, the bilayer phospholipid envelop prevents the dissociation in the magnetoliposome samples.

  17. Light scattering studies of an electrorheological fluid in oscillatory shear

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.E.; Odinek, J.

    1995-12-31

    We have conducted a real time, two-dimensional light scattering study of the nonlinear dynamics of field-induced structures in an electrorheological fluid subjected to oscillatory shear. We have developed a kinetic chain model of the observed dynamics by considering the response of a fragmenting/aggregating particle chain to the prevailing hydrodynamic and electrostatic forces. This structural theory is then used to describe the nonlinear rheology of ER fluids.

  18. Astrophysical fluid dynamics

    Science.gov (United States)

    Ogilvie, Gordon I.

    2016-06-01

    > These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

  19. Corrosion in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  20. Geophysical fluid dynamics

    CERN Document Server

    Pedlosky, Joseph

    1979-01-01

    The content of this book is based, largely, on the core curriculum in geophys­ ical fluid dynamics which I and my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same ti...