Aitova, E. V.; Bratsun, D. A.; Kostarev, K. G.; Mizev, A. I.; Mosheva, E. A.
2016-12-01
The development of convective instability in a two-layer system of miscible fluids placed in a narrow vertical gap has been studied theoretically and experimentally. The upper and lower layers are formed with aqueous solutions of acid and base, respectively. When the layers are brought into contact, the frontal neutralization reaction begins. We have found experimentally a new type of convective instability, which is characterized by the spatial localization and the periodicity of the structure observed for the first time in the miscible systems. We have tested a number of different acid-base systems and have found a similar patterning there. In our opinion, it may indicate that the discovered effect is of a general nature and should be taken into account in reaction-diffusion-convection problems as another tool with which the reaction can govern the movement of the reacting fluids. We have shown that, at least in one case (aqueous solutions of nitric acid and sodium hydroxide), a new type of instability called as the concentration-dependent diffusion convection is responsible for the onset of the fluid flow. It arises when the diffusion coefficients of species are different and depend on their concentrations. This type of instability can be attributed to a variety of double-diffusion convection. A mathematical model of the new phenomenon has been developed using the system of reaction-diffusion-convection equations written in the Hele-Shaw approximation. It is shown that the instability can be reproduced in the numerical experiment if only one takes into account the concentration dependence of the diffusion coefficients of the reagents. The dynamics of the base state, its linear stability and nonlinear development of the instability are presented. It is also shown that by varying the concentration of acid in the upper layer one can achieve the occurrence of chemo-convective solitary cell in the bulk of an almost immobile fluid. Good agreement between the
Running interfacial waves in two-layer fluid system subject to longitudinal vibrations
Goldobin, Denis S.; Pimenova, Anastasiya V.; Kovalevskaya, Kseniya V.; Lyubimov, Dmitry V.; Lyubimova, Tatyana P.
2014-01-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasi-stationary states of free interface in fluid dynamical systems subject to vibrations, revealed existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary proble...
Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations
Goldobin, D. S.; Pimenova, A. V.; Kovalevskaya, K. V.; Lyubimov, D. V.; Lyubimova, T. P.
2015-05-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)], 10.1007/BF02628017 reveals the instabilities of thin layers to be long wavelength.
Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations.
Goldobin, D S; Pimenova, A V; Kovalevskaya, K V; Lyubimov, D V; Lyubimova, T P
2015-05-01
We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)] reveals the instabilities of thin layers to be long wavelength.
A Numerical Study on Water Waves Generated by A Submerged Moving Body in A Two-Layer Fluid System
Institute of Scientific and Technical Information of China (English)
YANG Jia-Zhen; NG Chiu-On; ZHANG Dao-Hua
2009-01-01
This is a numerical study on the time development of surface waves generated by a submerged body moving steadily in a two-layer fluid system, in which a layer of water is underlain by a layer of viscous mud. The fully nonlinear Navier-Stokes equations are solved on FLUENT with the Volume-of-Fluid (VOF) multiphase scheme in order to simulate the free surface waves as well as the water-mud interface waves as functions of time. The numerical model is validated by mimick-ing a reported experiment in a one-layer system before it is applied to a two-layer system, it is found that the presence of bottom mud in a water layer can lead to large viscous damping of the surface waves. For the investigation of the problem systematically, the effects of the Froude number and the mud layer thickness, density and viscosity relative to those of water are evaluated and discussed in detail.
Directory of Open Access Journals (Sweden)
Linga Raju T.
2016-05-01
Full Text Available An unsteady MHD two-layered fluid flow of electrically conducting fluids in a horizontal channel bounded by two parallel porous plates under the influence of a transversely applied uniform strong magnetic field in a rotating system is analyzed. The flow is driven by a common constant pressure gradient in a channel bounded by two parallel porous plates, one being stationary and the other oscillatory. The two fluids are assumed to be incompressible, electrically conducting with different viscosities and electrical conductivities. The governing partial differential equations are reduced to the linear ordinary differential equations using two-term series. The resulting equations are solved analytically to obtain exact solutions for the velocity distributions (primary and secondary in the two regions respectively, by assuming their solutions as a combination of both the steady state and time dependent components of the solutions. Numerical values of the velocity distributions are computed for different sets of values of the governing parameters involved in the study and their corresponding profiles are also plotted. The details of the flow characteristics and their dependence on the governing parameters involved, such as the Hartmann number, Taylor number, porous parameter, ratio of the viscosities, electrical conductivities and heights are discussed. Also an observation is made how the velocity distributions vary with the rotating hydromagnetic interaction in the case of steady and unsteady flow motions. The primary velocity distributions in the two regions are seen to decrease with an increase in the Taylor number, but an increase in the Taylor number causes a rise in secondary velocity distributions. It is found that an increase in the porous parameter decreases both the primary and secondary velocity distributions in the two regions.
Linga Raju, T.; Neela Rao, B.
2016-08-01
The paper aims to analyze the heat transfer aspects of a two-layered fluid flow in a horizontal channel under the action of an applied magnetic and electric fields, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a common constant pressure gradient in the channel bounded by two parallel porous insulating plates, one being stationary and the other one oscillatory. The fluids in the two regions are considered electrically conducting, and are assumed to be incompressible with variable properties, namely, different densities, viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperature. The governing partial differential equations are then reduced to the ordinary linear differential equations by using a two-term series. The temperature distributions in both fluid regions of the channel are derived analytically. The results are presented graphically to discuss the effect on the heat transfer characteristics and their dependence on the governing parameters, i.e., the Hartmann number, Taylor number, porous parameter, and ratios of the viscosities, heights, electrical and thermal conductivities. It is observed that, as the Coriolis forces become stronger, i.e., as the Taylor number increases, the temperature decreases in the two fluid regions. It is also seen that an increase in porous parameter diminishes the temperature distribution in both the regions.
Linear waves in two-layer fluids over periodic bottoms
Yu, Jie; Maas, L.R.M.
2016-01-01
A new, exact Floquet theory is presented for linear waves in two-layer fluids over a periodic bottom of arbitrary shape and amplitude. A method of conformal transformation is adapted. The solutions are given, in essentially analytical form, for the dispersion relation between wave frequency and gene
Zhao, Xue-Hui; Tian, Bo; Chai, Jun; Wu, Yu-Xiao; Guo, Yong-Jiang
2016-11-01
Under investigation in this paper is a generalized variable-coefficient Boussinesq system, which describes the propagation of the shallow water waves in the two-layered fluid flow. Bilinear forms, Bäcklund transformation and Lax pair are derived by virtue of the Bell polynomials. Hirota method is applied to construct the one- and two-soliton solutions. Propagation and interaction of the solitons are illustrated graphically: kink- and bell-shape solitons are obtained; shapes of the solitons are affected by the variable coefficients α1, α3 and α4 during the propagation, kink- and anti-bell-shape solitons are obtained when α3 > 0, anti-kink- and bell-shape solitons are obtained when α3 < 0; Head-on interaction between the two bidirectional solitons, overtaking interaction between the two unidirectional solitons are presented; interactions between the two solitons are elastic.
THE WAVE-MAKING CHARACTERISTICS OF A MOVING BODY IN A TWO-LAYER FLUID
Institute of Scientific and Technical Information of China (English)
ZHU Wei
2005-01-01
The Wave-making characteristics of a moving body in a two-layer fluid with free surface is investigated numerically and experimentally. The numerical analysis is based on the modified layered boundary integral equation system. The wave characteristics on the free surface and interface generated by a moving sphere and an ellipsoid is numerically simulated in both finite depth and infinite depth of lower layer model. The numerical results of the sphere are compared with the analytical results for a dipole with the same velocity in a two-layer fluid of finite depth. The dependence of the wave systems and structures on the characteristic quantities is discussed. Three kinds of measurement techniques are used in model experiments on the internal waves generated by a sphere advancing in a two-layer fluid. The effects of the varying velocity and stratification on the wavelength, wave amplitudes and the maximum half angles of internal waves are analyzed qualitatively.
Linear waves in two-layer fluids over periodic bottoms
Yu, J.; Maas, L.R.M.
2016-01-01
A new, exact Floquet theory is presented for linear waves in two-layer fluidsover a periodic bottom of arbitrary shape and amplitude. A method of conformaltransformation is adapted. The solutions are given, in essentially analytical form, forthe dispersion relation between wave frequency and general
Diffraction of Water Waves by A Vertically Floating Cylinder in A Two-Layer Fluid
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer luid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder are obtained by use of the method of eigenfunction expansions. The hydrodynamic loads on the vertically floating cylinder in a two-layer fluid include not only the surge, heave and pitch exciting forces due to the incident wave of the surface-wave mode, but also those due to the incident wave of the internal-wave mode. This is different from the case of a homogenous fluid. Some given examples show that, for a two-layer fluid system with a small density difference, the hydrodynamic loads for the surface-wave mode do not differ significantly from those due to surface waves in a single-layer fluid, but the hydrodynamic loads for the internal-wave mode are important over a wide range of frequencies. Moreover, also considered are the free surface and interface elevations generated by the diffraction wave due to the incident wave of the surface-wave and internal-wave modes, and transfer of energy between modes.
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.
MHD two-layered unsteady fluid flow and heat transfer through a horizontal channel between
Directory of Open Access Journals (Sweden)
Raju T. Linga
2014-02-01
Full Text Available An unsteady magnetohydrodynamic (MHD two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a constant uniform pressure gradient in the channel bounded by two parallel insulating plates, when both fluids are considered as electrically conducting, incompressible with variable properties, viz. different viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperatures. The governing partial differential equations are then reduced to the ordinary linear differential equations using two-term series. Closed form solutions for primary and secondary velocity, also temperature distributions are obtained in both the fluid regions of the channel. Profiles of these solutions are plotted to discuss the effects of the flow and heat transfer characteristics, and their dependence on the governing parameters involved, such as the Hartmann number, rotation parameter, ratios of the viscosities, heights, electrical and thermal conductivities
Free surface simulation of a two-layer fluid by boundary element method
Directory of Open Access Journals (Sweden)
Weoncheol Koo
2010-09-01
Full Text Available A two-layer fluid with free surface is simulated in the time domain by a two-dimensional potential-based Numerical Wave Tank (NWT. The developed NWT is based on the boundary element method and a leap-frog time integration scheme. A whole domain scheme including interaction terms between two layers is applied to solve the boundary integral equation. The time histories of surface elevations on both fluid layers in the respective wave modes are verified with analytic results. The amplitude ratios of upper to lower elevation for various density ratios and water depths are also compared.
Steady internal waves in an exponentially stratified two-layer fluid
Makarenko, Nikolay; Maltseva, Janna; Ivanova, Kseniya
2016-04-01
The problem on internal waves in a weakly stratified two-layered fluid is studied analytically. We suppose that the fluid possess exponential stratification in both the layers, and the fluid density has discontinuity jump at the interface. By that, we take into account the influence of weak continuous stratification outside of sharp pycnocline. The model equation of strongly nonlinear interfacial waves propagating along the pycnocline is considered. This equation extends approximate models [1-3] suggested for a two-layer fluid with one homogeneous layer. The derivation method uses asymptotic analysis of fully nonlinear Euler equations. The perturbation scheme involves the long wave procedure with a pair of the Boussinesq parameters. First of these parameters characterizes small density slope outside of pycnocline and the second one defines small density jump at the interface. Parametric range of solitary wave solutions is characterized, including extreme regimes such as plateau-shape solitary waves. This work was supported by RFBR (grant No 15-01-03942). References [1] N. Makarenko, J. Maltseva. Asymptotic models of internal stationary waves, J. Appl. Mech. Techn. Phys, 2008, 49(4), 646-654. [2] N. Makarenko, J. Maltseva. Phase velocity spectrum of internal waves in a weakly-stratified two-layer fluid, Fluid Dynamics, 2009, 44(2), 278-294. [3] N. Makarenko, J. Maltseva. An analytical model of large amplitude internal solitary waves, Extreme Ocean Waves, 2nd ed. Springer 2015, E.Pelinovsky and C.Kharif (Eds), 191-201.
Design and analysis of two-layer anonymous communication system
Institute of Scientific and Technical Information of China (English)
WANG Wei-ping; WANG Jian-xin
2007-01-01
A new architecture for scalable anonymous communication system(SACS) was proposed. The users were divided into several subgroups managed by different sub-blenders, and all sub-blenders were managed by the main-blender using two layers management scheme. The identity information of members are distributed on different sub-blenders, which makes each member keep much less information and network overload greatly reduce. The anonymity and the overhead of the new scheme were analyzed and compared with that of Crowds, which shows the cost of storage and network overhead for the new scheme largely decreases while the anonymity is little degraded. The experiment results also show that the new system architecture is well scalable. The ratio of management cost of SACS to that of Crowds is about 1:25 while the value of P(I|H1+) only increases by 0.001-0.020, which shows that SACS keeps almost the same anonymity with Crowds.
Wave turbulence in a two-layer fluid: coupling between free surface and interface waves
Issenmann, Bruno; Falcon, Eric
2016-01-01
We experimentally study gravity-capillary wave turbulence on the interface between two immiscible fluids of close density with free upper surface. We locally measure the wave height at the interface between both fluids by means of a highly sensitive laser Doppler vibrometer. We show that the inertial range of the capillary wave turbulence regime is significantly extended when the upper fluid depth is increased: The crossover frequency between the gravity and capillary wave turbulence regimes is found to decrease whereas the dissipative cut-off frequency of the spectrum is found to increase. We explain most of these observations by the progressive decoupling between waves propagating at the interface and the ones at the free surface, using the full dispersion relation of gravity-capillary waves in a two-layer fluid of finite depths.s.
Institute of Scientific and Technical Information of China (English)
LU Dong-qiang; SUN Cui-zhi
2013-01-01
Generation of the transient flexural-and capillary-gravity waves by impulsive disturbances in a two-layer fluid is investigated analytically.The upper fluid is covered by a thin elastic plate or by an inertial surface with the capillary effect.The density of each of the two immiscible layers is constant.The fluids are assumed to be inviscid and incompressible and the motion be irrotational.A point force on the surface and simple mass sources in the upper and lower fluid layers are considered.A linear system is established within the framework of potential theory.The integral solutions for the surface and interfacial waves are obtained by means of the Laplace-Fourier transform.A new representation for the dispersion relation of flexural-and capillary-gravity waves in a two-layer fluid is derived.The asymptotic representations of the wave motions are derived for large time with a fixed distance-to-time ratio with the Stokes and Scorer methods of stationary phase.It is shown that there are two different modes,namely the surface and interfacial wave modes.The wave systems observed depend on the relation between the observer's moving speed and the intrinsic minimal and maximal group velocities.
Global chaotization of fluid particle trajectories in a sheared two-layer two-vortex flow
Energy Technology Data Exchange (ETDEWEB)
Ryzhov, Evgeny A., E-mail: ryzhovea@poi.dvo.ru [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Koshel, Konstantin V., E-mail: kvkoshel@poi.dvo.ru [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Far Eastern Federal University, 8, Sukhanova Street, Vladivostok 690950 (Russian Federation)
2015-10-15
In a two-layer quasi-geostrophic approximation, we study the irregular dynamics of fluid particles arising due to two interacting point vortices embedded in a deformation flow consisting of shear and rotational components. The two vortices are arranged within the bottom layer, but an emphasis is on the upper-layer fluid particle motion. Vortices moving in one layer induce stirring of passive scalars in the other layer. This is of interest since point vortices induce singular velocity fields in the layer they belong to; however, in the other layer, they induce regular velocity fields that generally result in a change in passive particle stirring. If the vortices are located at stagnation points, there are three different types of the fluid flow. We examine how properties of each flow configuration are modified if the vortices are displaced from the stagnation points and thus circulate in the immediate vicinity of these points. To that end, an analysis of the steady-state configurations is presented with an emphasis on the frequencies of fluid particle oscillations about the elliptic stagnation points. Asymptotic relations for the vortex and fluid particle zero–oscillation frequencies are derived in the vicinity of the corresponding elliptic points. By comparing the frequencies of fluid particles with the ones of the vortices, relations between the parameters that lead to enhanced stirring of fluid particles are established. It is also demonstrated that, if the central critical point is elliptic, then the fluid particle trajectories in its immediate vicinity are mostly stable making it harder for the vortex perturbation to induce stirring. Change in the type of the central point to a hyperbolic one enhances drastically the size of the chaotic dynamics region. Conditions on the type of the central critical point also ensue from the derived asymptotic relations.
WAVES GENERATED BY A 3D MOVING BODY IN A TWO-LAYER FLUID OF FINITE DEPTH
Institute of Scientific and Technical Information of China (English)
ZHU Wei; YOU Yun-xiang; MIAO Guo-ping; ZHAO Feng; ZHANG Jun
2005-01-01
This paper is concerned with the waves generated by a 3-D body advancing beneath the free surface with constant speed in a two-layer fluid of finite depth. By applying Green's theorem, a layered integral equation system based on the Rankine source for the perturbed velocity potential generated by the moving body was derived with the potential flow theory. A four-node isoparametric element method was used to treat with the solution of the layered integral equation system. The surface and interface waves generated by a moving ball were calculated numerically. The results were compared with the analytical results for a moving source with constant velocity.
Effect of slip boundary conditions on interfacial stability of two-layer viscous fluids under shear
Patlazhan, Stanislav
2015-01-01
The traditional approach in the study of hydrodynamic stability of stratified fluids includes the stick boundary conditions between layers. However, this rule may be violated in polymer systems and as a consequence various instabilities may arise. The main objective of this paper is to analyze theoretically the influence of slip boundary conditions on the hydrodynamic stability of the interface between two immiscible viscous layers subjected to simple shear flow. It is found that the growth rate of long-wave disturbances is fairly sensitive to the slip at the interface between layers as well as at the external boundary. These phenomena are shown to give different contributions to the stability of shear flow depending on viscosity, thickness, and density ratios of the layers. Particularly, the interfacial slip can increase the perturbation growth rate and lead to unstable flow. An important consequence of this effect is the violation of stability for sheared layers with equal viscosities and densities in a bro...
Kurakin, Leonid G.; Ostrovskaya, Irina V.; Sokolovskiy, Mikhail A.
2016-05-01
A two-layer quasigeostrophic model is considered in the f-plane approximation. The stability of a discrete axisymmetric vortex structure is analyzed for the case when the structure consists of a central vortex of arbitrary intensity Γ and two/three identical peripheral vortices. The identical vortices, each having a unit intensity, are uniformly distributed over a circle of radius R in a single layer. The central vortex lies either in the same or in another layer. The problem has three parameters ( R, Γ, α), where α is the difference between layer thicknesses. A limiting case of a homogeneous fluid is also considered. A limiting case of a homogeneous fluid is also considered. The theory of stability of steady-state motions of dynamic systems with a continuous symmetry group G is applied. The two definitions of stability used in the study are Routh stability and G-stability. The Routh stability is the stability of a one-parameter orbit of a steady-state rotation of a vortex multipole, and the G-stability is the stability of a three-parameter invariant set O G , formed by the orbits of a continuous family of steady-state rotations of a multipole. The problem of Routh stability is reduced to the problem of stability of a family of equilibria of a Hamiltonian system. The quadratic part of the Hamiltonian and the eigenvalues of the linearization matrix are studied analytically. The cases of zero total intensity of a tripole and a quadrupole are studied separately. Also, the Routh stability of a Thomson vortex triangle and square was proved at all possible values of problem parameters. The results of theoretical analysis are sustained by numerical calculations of vortex trajectories.
Institute of Scientific and Technical Information of China (English)
Dan MA
2014-01-01
A two-layer switching architecture and a two-layer switching rule for stabilization of switched linear control systems are proposed, under which the mismatched switching between switched systems and their candidate hybrid controllers can be allowed. In the low layer, a state-dependent switching rule with a dwell time constraint to exponentially stabilize switched linear systems is given;in the high layer, supervisory conditions on the mismatched switching frequency and the mismatched switching ratio are presented, under which the closed-loop switched system is still exponentially stable in case of the candidate controller switches delay with respect to the subsystems. Different from the traditional switching rule, the two-layer switching architecture and switching rule have robustness, which in some extend permit mismatched switching between switched subsystems and their candidate controllers.
Band splitting and relative spin alignment in two-layer systems
Ovchinnikov, A A
2002-01-01
It is shown that the single-particle spectra of the low Hubbard zone in the two-layer correlated 2D-systems sharply differ in the case of different relative alignment of the layers spin systems. The behavior of the two-layer splitting in the Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub + subdelta gives all reasons for the hypothesis on the possible rearrangement of the F sub z -> AF sub z alignment configuration, occurring simultaneously with the superconducting transition. The effects of the spin alignment on the magnetic excitations spectrum, as the way for studying the spin structure of the two-layer systems, are discussed by the example of homogenous solutions for the effective spin models
Low-frequency wave propagation in an elastic plate loaded by a two-layer fluid
DEFF Research Database (Denmark)
Indeitsev, Dmitrij; Sorokin, Sergey
2012-01-01
of salty water. The former one produces fluid loading at the plate, whereas the latter one is bounded by the sea bottom. We employ classical asymptotic methods to identify significant regimes of wave motion in the compound three-component waveguide. The roles of parameters involved in the problem...
Low-frequency wave propagation in an elastic plate loaded by a two-layer fluid
DEFF Research Database (Denmark)
Indeitsev, Dmitrij; Sorokin, Sergey
2012-01-01
In several technical applications, for example, in the Arctic off-shore oil industry, it is necessary to predict waveguide properties of floating elastic plates in contact with a relatively thin layer of water, which has a non-uniform density distribution across its depth. The issue of particular...... concern is propagation of low-frequency waves in such a coupled waveguide. In the present paper, we assume that an inhomogeneous fluid may be modelled as two homogeneous, inviscid and incompressible layers with slightly different densities. The lighter layer of fresh water lies on top of the heavier layer...... of salty water. The former one produces fluid loading at the plate, whereas the latter one is bounded by the sea bottom. We employ classical asymptotic methods to identify significant regimes of wave motion in the compound three-component waveguide. The roles of parameters involved in the problem...
Interaction of water waves with small undulations on a porous bed in a two-layer ice-covered fluid
Panda, Srikumar; Martha, S. C.
2013-12-01
The scattering problem involving water waves by small undulation on the porous ocean-bed in a two-layer fluid, is investigated within the framework of the two-dimensional linear water wave theory where the upper layer is covered by a thin uniform sheet of ice modeled as a thin elastic plate. In such a two-layer fluid there exist waves with two different modes, one with a lower wave number propagate along the ice-cover whilst those with a higher wave number propagate along the interface. An incident wave of a particular wave number gets reflected and transmitted over the bottom undulation into waves of both modes. Perturbation analysis in conjunction with the Fourier transform technique is used to derive the first-order corrections of reflection and transmission coefficients for both the modes due to incident waves of two different modes. One special type of bottom topography is considered as an example to evaluate the related coefficients in detail. These coefficients are depicted in graphical forms to demonstrate the transformation of wave energy between the two modes and also to illustrate the effects of the ice sheet and the porosity of the undulating bed.
A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer
Institute of Scientific and Technical Information of China (English)
Kadry Zakaria; Magdy A. Sirwah; Sameh A. Alkharashi
2011-01-01
Based on a modified-Darcy-Maxwell model, two-dimensional, incompressible and heat transfer flow of two bounded layers, through electrified Maxwell fluids in porous media is performed. The driving force for the instability under an electric field, is an electrostatic force exerted on the free charges accumulated at the dividing interface. Normal mode analysis is considered to study the linear stability of the disturbances layers. The solutions of the linearized equations of motion with the boundary conditions lead to an implicit dispersion relation between the growth rate and wave number. These equations are parameterized by Weber number, Reynolds number, Marangoni number, dimensionless conductivities, and dimensionless electric potentials. The case of long waves interfacial stability has been studied. The stability criteria are performed theoretically in which stability diagrams are obtained. In the limiting cases, some previously published results can be considered as particular cases of our results. It is found that the Reynolds number plays a destabilizing role in the stability criteria, while the damping influence is observed for the increasing of Marangoni number and Maxwell relaxation time.
A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer
Kadry, Zakaria; Magdy, A. Sirwah; Sameh, A. Alkharashi
2011-06-01
Based on a modified-Darcy—Maxwell model, two-dimensional, incompressible and heat transfer flow of two bounded layers, through electrified Maxwell fluids in porous media is performed. The driving force for the instability under an electric field, is an electrostatic force exerted on the free charges accumulated at the dividing interface. Normal mode analysis is considered to study the linear stability of the disturbances layers. The solutions of the linearized equations of motion with the boundary conditions lead to an implicit dispersion relation between the growth rate and wave number. These equations are parameterized by Weber number, Reynolds number, Marangoni number, dimensionless conductivities, and dimensionless electric potentials. The case of long waves interfacial stability has been studied. The stability criteria are performed theoretically in which stability diagrams are obtained. In the limiting cases, some previously published results can be considered as particular cases of our results. It is found that the Reynolds number plays a destabilizing role in the stability criteria, while the damping influence is observed for the increasing of Marangoni number and Maxwell relaxation time.
Diffraction of Oblique Water Waves by Small Uneven Channel-bed in a Two-layer Fluid
Institute of Scientific and Technical Information of China (English)
Smrutiranjan Mohapatra
2014-01-01
Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.
Diffraction of oblique water waves by small uneven channel-bed in a two-layer fluid
Mohapatra, Smrutiranjan
2014-09-01
Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.
Oblique wave scattering by an undulating porous bottom in a two-layer ice-covered fluid
Panda, Srikumar
2016-06-01
The present study analyzes the reflection and transmission phenomenon of water-waves in a two-layer ice-covered system. The upper layer is covered by an ice-sheet, whereas the bottom of the lower layer is undulated and permeable. By using regular perturbation analysis and Fourier transform technique, the problem is solved and the first order reflection and transmission coefficients are determined. It is found that these coefficients depend on the shape as well as the permeability of the undulating bottom. Therefore, from the practical viewpoint, an undulating bottom topography is considered to determine all the aforesaid coefficients. The role of various system parameters, such as porosity, angle of incidence and ice parameters, are discussed to analyze the transformation of incident water wave energy from one layer to another layer. The outcomes are demonstrated in graphical forms.
Oblique Water Wave Scattering by Bottom Undulation in a Two-layer Fluid Flowing Through a Channel
Institute of Scientific and Technical Information of China (English)
Smrutiranjan Mohapatra; Swaroop Nandan Bora
2012-01-01
The problem of oblique wave (internal wave) propagation over a small deformation in a channel flow consisting of two layers was considered.The upper fluid was assumed to be bounded above by a rigid lid,which is an approximation for the free surface,and the lower one was bounded below by an impermeable bottom surface having a small deformation; the channel was unbounded in the horizontal directions.Assuming irrotational motion,the perturbation technique was employed to calculate the first-order corrections of the velocity potential in the two fluids by using Green's integral theorem suitably with the introduction of appropriate Green's functions.Those functions help in calculating the reflection and transmission coefficients in terms of integrals involving the shape function c(x) representing the bottom deformation.Three-dimensional linear water wave theory was utilized for formulating the relevant boundary value problem.Two special examples of bottom deformation were considered to validate the results.Consideration of a patch of sinusoidal ripples (having the same wave number) shows that the reflection coefficient is an oscillatory function of the ratio of twice the x-component of the wave number to the ripple wave number.When this ratio approaches one,the theory predicts a resonant interaction between the bed and the interface,and the reflection coefficient becomes a multiple of the number of tipples.High reflection of incident wave energy occurs if this number is large.Similar results were observed for a patch of sinusoidal tipples having different wave numbers.It was also observed that for small angles of incidence,the reflected energy is greater compared to other angles of incidence up to π / 4.These theoretical observations are supported by graphical results.
Sahu, K. C.; Matar, O. K.
2010-11-01
The three-dimensional linear stability characteristics of pressure-driven two-layer channel flow are considered, wherein a Newtonian fluid layer overlies a layer of a Herschel-Bulkley fluid. We focus on the parameter ranges for which Squire's theorem for the two-layer Newtonian problem does not exist. The modified Orr-Sommerfeld and Squire equations in each layer are derived and solved using an efficient spectral collocation method. Our results demonstrate the presence of three-dimensional instabilities for situations where the square root of the viscosity ratio is larger than the thickness ratio of the two layers; these "interfacial" mode instabilities are also present when density stratification is destabilizing. These results may be of particular interest to researchers studying the transient growth and nonlinear stability of two-fluid non-Newtonian flows. We also show that the "shear" modes, which are present at sufficiently large Reynolds numbers, are most unstable to two-dimensional disturbances.
Institute of Scientific and Technical Information of China (English)
李新政; 白占国; 李燕; 贺亚峰; 赵昆
2015-01-01
The resonance interaction between two modes is investigated using a two-layer coupled Brusselator model. When two different wavelength modes satisfy resonance conditions, new modes will appear, and a variety of superlattice patterns can be obtained in a short wavelength mode subsystem. We find that even though the wavenumbers of two Turing modes are fixed, the parameter changes have infl uences on wave intensity and pattern selection. When a hexagon pattern occurs in the short wavelength mode layer and a stripe pattern appears in the long wavelength mode layer, the Hopf instability may happen in a nonlinearly coupled model, and twinkling-eye hexagon and travelling hexagon patterns will be obtained. The symmetries of patterns resulting from the coupled modes may be different from those of their parents, such as the cluster hexagon pattern and square pattern. With the increase of perturbation and coupling intensity, the nonlinear system will con-vert between a static pattern and a dynamic pattern when the Turing instability and Hopf instability happen in the nonlinear system. Besides the wavenumber ratio and intensity ratio of the two different wavelength Turing modes, perturbation and coupling intensity play an important role in the pattern formation and selection. According to the simulation results, we find that two modes with different symmetries can also be in the spatial resonance under certain conditions, and complex patterns appear in the two-layer coupled reaction diffusion systems.
Two-Layer Coding Rate Optimization in Relay-Aided Systems
DEFF Research Database (Denmark)
Sun, Fan
2011-01-01
We consider a three-node transmission system, where a source node conveys a data block to a destination node with the help of a half-duplex decode and-forward (DF) relay node. The whole data block is transmitted as a sequence of packets. For reliable transmission in the three-node system, a two......-layer coding scheme is proposed, where physical layer channel coding is utilized within each packet for error-correction and random network coding is applied on top of channel coding for network error-control. There is a natural tradeoff between the physical layer coding rate and the network coding rate given...... requirement. Numerical results are also provided to show the optimized physical layer coding and network coding rate pairs in different system scenarios....
Analysis of data recorded by the LCTPC equipped with a two layer GEM-system
Ljunggren, M
2012-01-01
wire based readout. The prototype TPC is placed in a 1 Tesla magnet at DESY and tested using an electron beam. Analyses of data taken during two different measurement series, in 2009 and 2010, are presented here. The TPC was instrumented with a two layer GEM system and read out using modified electronics from the ALICE experiment, including the programmable charge sensitive preamp-shaper PCA16. The PCA16 chip has a number of programmable parameters which allows studies to determine the settings optimal to the final TPC. Here, the impact of the shaping time on the space resolution in the drift direction was studied. It was found that a shaping time of 60 ns is the b...
Convergent flow in a two-layer system and mountain building
Perazzo, Carlos Alberto
2009-01-01
With the purpose of modelling the process of mountain building, we investigate the evolution of the ridge produced by the convergent motion of a system consisting of two layers of liquids that differ in density and viscosity to simulate the crust and the upper mantle that form a lithospheric plate. We assume that the motion is driven by basal traction. Assuming isostasy, we derive a nonlinear differential equation for the evolution of the thickness of the crust. We solve this equation numerically to obtain the profile of the range. We find an approximate self-similar solution that describes reasonably well the process and predicts simple scaling laws for the height and width of the range as well as the shape of the transversal profile. We compare the theoretical results with the profiles of real mountain belts and find and excellent agreement.
Method of the Moulding Sands Binding Power Assessment in Two-Layer Moulds Systems
Directory of Open Access Journals (Sweden)
M. Holtzer
2014-07-01
Full Text Available More and more foundry plants applying moulding sands with water-glass or its substitutes for obtaining the high-quality casting surface at the smallest costs, consider the possibility of implementing two-layer moulds, in which e.g. the facing sand is a sand with an organic binder (no-bake type and the backing sand is a sand with inorganic binder. Both kinds of sands must have the same chemical reaction. The most often applied system is the moulding sand on the water-glass or geopolymer bases - as the backing sand and the moulding sand from the group of self-hardening sands with a resol resin - as the facing sand. Investigations were performed for the system: moulding sand with inorganic GEOPOL binder or moulding sand with water glass (as a backing sand and moulding sand, no-bake type, with a resol resin originated from various producers: Rezolit AM, Estrofen, Avenol NB 700 (as a facing sand. The LUZ apparatus, produced by Multiserw Morek, was adapted for investigations. A special partition with cuts was mounted in the attachment for making test specimens for measuring the tensile strength. This partition allowed a simultaneous compaction of two kinds of moulding sands. After 24 hours of hardening the highest values were obtained for the system: Geopol binder - Avenol resin.
Steady thermocapillary flows in a two-layer liquid system with flat interfaces
del Arco, E. Crespo; Extremet, G. P.; Sani, R. L.
1993-01-01
Steady thermocapillary convection is studied in a system of two flat, superposed layers of immiscible liquids with two fluid-fluid interfaces in a configuration similar to that of an encapsulated crystal growth. The layers are bounded on the sides by isothermal vertical walls maintained at different constant temperatures. A simplified analytical solution is used initially to explore different potential flow regimes in a parameter space of large dimensionality. Then the coupled Navier-Stokes and heat transfer equations are solved numerically with a finite element method via FIDAP, in a rectangular cavity filled with two immiscible liquids in the absence of a gravitational field.
Lai, Yen-Shou; Tsai, Hung-Hsu; Yu, Pao-Ta
2011-01-01
This paper proposes a new presentation system integrating a Microsoft PowerPoint presentation in a two-layer method, called the TL system, to promote learning in a physical classroom. With the TL system, teachers can readily control hints or annotations as a way of making them visible or invisible to students so as to reduce information load. In…
Elhanaoui, Abdelkader; Aassif, Elhoucein; Maze, Gérard; Décultot, Dominique
2016-02-01
The present paper studies the acoustic signal backscattered by an air-filled copper–solid polymer two-layer cylindrical tube immersed in water. The work is done from the calculation of the backscattered pressure, an inverse Fourier Transform, which allows us to obtain an impulse signal. Smoothed pseudo Wigner–Ville and Concentrated spectrogram representations have been chosen to analyze the scattering phenomenon. For reduced frequencies ranging from 0.1 to 200, the resonance trajectories and time–frequency images have shown the presence of the guided waves. The bifurcation of the A0 wave into the A0(-) and the A0(+) waves has also been observed. The authors provide the phase and the group velocities of guided waves and investigate the differences between curves. The findings are then compared with those obtained for the copper and the solid polymer one-layer cylindrical tubes. Group velocity values have also been extracted from smoothed pseudo Wigner–Ville and Concentrated spectrogram time–frequency images. A good agreement with the theory has, therefore, been observed. The study of acoustic backscattering by a copper–solid polymer two-layer tube has revealed the interaction and the coupling of guided waves, specially the presence of a pseudo A1 wave; which is a very interesting, remarkable phenomenon.
Moyers-Gonzalez, M.; Frigaard, I. A.; Nouar, Cherif
2010-01-01
Multi-fluid flows are frequently thought of as being less stable than single phase flows. Consideration of different non-Newtonian models can give rise to different types of hydrodynamic instability. Here we show that with careful choice of fluid rheologies and flow paradigm, one can achieve multi-l
Moyers-Gonzalez, M.; Frigaard, I. A.; Nouar, Cherif
2010-01-01
Multi-fluid flows are frequently thought of as being less stable than single phase flows. Consideration of different non-Newtonian models can give rise to different types of hydrodynamic instability. Here we show that with careful choice of fluid rheologies and flow paradigm, one can achieve multi-l
Cournil, Michel; Herri, Jean-Michel
2002-01-01
6 pages; This paper proposes to re-visit the problem of gas-liquid crystallization in the framework of a two-layer model and with the help of data coming from experiments on methane hydrate crystallization in a semi-batch reactor. Preliminary quantitative discussion of the order of magnitude of different effects makes possible realistic simplifications in the theoretical models. In particular, the role of the interfacial film is clearly defined. As previous authors did, we use a formulation i...
Flows induced by sorption on fibrous material in a two-layer oil-water system
Chaplina, T. O.; Chashechkin, Yu. D.; Stepanova, E. V.
2016-09-01
The processes of sorption on fibrous materials in the open elliptic cell filled with a two-layer oil-water liquid at rest are investigated experimentally. When the sorption efficiency dependent on the type of material proves to be reasonably high, large-scale flows are formed in the liquid. In this case, the uniformity of distribution of oil is violated and the free surface of the water is partially restored. The trajectories of motion of individual oil droplets on a released water surface are tracked, and the transfer rates are calculated in various phases of the process.
Energy Technology Data Exchange (ETDEWEB)
Stursberg, Olaf; Paschedag, Tina; Rungger, Matthias; Ding, Hao [Kassel Univ. (Germany). Fachgebiet Regelungs- und Systemtheorie
2010-08-15
While hybrid dynamic models are, to a certain degree, established for modeling systems with heterogeneous dynamics, most approaches for design and analysis of hybrid systems are restricted to monolithic models without hierarchy. This contribution first shows, how modular hybrid systems with two layers of decision, as appropriate for representing manufacturing systems for example, can be modeled systematically. The second part proposes a technique for fixing discrete inputs (for coordinating control) and continuous inputs (for embedded continuous controllers) in combination. The method uses a graph-based search on the upper decision layer, while principles of predictive control are used on the lower layer. The procedure of modeling and control is illustrated for a manufacturing process. (orig.)
Kodama, Yu; Hamagami, Tomoki
Distributed processing system for restoration of electric power distribution network using two-layered CNP is proposed. The goal of this study is to develop the restoration system which adjusts to the future power network with distributed generators. The state of the art of this study is that the two-layered CNP is applied for the distributed computing environment in practical use. The two-layered CNP has two classes of agents, named field agent and operating agent in the network. In order to avoid conflicts of tasks, operating agent controls privilege for managers to send the task announcement messages in CNP. This technique realizes the coordination between agents which work asynchronously in parallel with others. Moreover, this study implements the distributed processing system using a de-fact standard multi-agent framework, JADE(Java Agent DEvelopment framework). This study conducts the simulation experiments of power distribution network restoration and compares the proposed system with the previous system. We confirmed the results show effectiveness of the proposed system.
Thermal properties of composite two-layer systems with a fractal inclusion structure
Reyes-Salgado, J. J.; Dossetti, V.; Bonilla-Capilla, B.; Carrillo, J. L.
2015-01-01
In this work, we study the thermal transport properties of platelike composite two-layer samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy and thermal relaxation, their effective thermal diffusivity and conductivity were experimentally measured. The composite layers were prepared under the action of a static magnetic field, resulting in anisotropic (fractal) inclusion structures with the formation of chain-like magnetite aggregates parallel to the faces of the layers. In one kind of the bilayers, a composite layer was formed on top of a resin layer while their relative thickness was varied. These samples can be described by known models. In contrast, bilayers with the same concentration of inclusions and the same thickness on both sides, where only the angle between their inclusion structures was systematically varied, show a nontrivial behaviour of their thermal conductivity as a function of this angle. Through a multifractal and lacunarity analysis, we explain the observed thermal response in terms of the complexity of the interface between the layers.
Two-Layer Coding Rate Optimization in Relay-Aided Systems
DEFF Research Database (Denmark)
Sun, Fan
2011-01-01
We consider a three-node transmission system, where a source node conveys a data block to a destination node with the help of a half-duplex decode and-forward (DF) relay node. The whole data block is transmitted as a sequence of packets. For reliable transmission in the three-node system, a two...... different system performance requirements. For different objectives, two optimization problems are formulated and solutions are presented. One is to minimize the outage probability given the efficiency requirement, while the other one is to maximize the transmission efficiency given the outage probability...... requirement. Numerical results are also provided to show the optimized physical layer coding and network coding rate pairs in different system scenarios....
National Research Council Canada - National Science Library
Küçükyılmaz, Kamil; Bozkurt, Mehmet; Herken, Emine Nur; Cınar, Mustafa; Catlı, Abdullah Uğur; Bintaş, Erol; Cöven, Fethiye
2012-01-01
.... Egg weight exhibited a similar pattern to that of laying performance. However, the total hen-housed egg number for the white birds in the organic system was fewer than that of white birds in the conventional cage facility...
Marangoni instabilities in two-layer systems due to concentration dependent transfer properties
Trevelyan, P. M. J.; Pimienta, V.; Eckert, K.; de Wit, A.
2008-11-01
We consider a Hele-Shaw cell containing two immiscible liquids. A chemical species initially dissolved in an organic phase crosses the interface into the aqueous phase. In the aqueous phase this chemical reactant is involved in a reaction producing a surfactant which undergoes micellisation when the critical micelle concentration is reached. These micelles increase solubility which in turn increases the transfer rate and hence favours additional formation of micelles. To model such an autocatalytic increase of solubility, we consider here that the partition coefficient is a function of the surfactant concentration. Through the solutal Marangoni effect, this surfactant can induce tangential stresses leading to interfacial motion. The aim of our study is to theoretically examine the conditions for an instability in such a system. In particular, we seek to understand whether Marangoni effects can be observed because of a concentration dependent partition coefficient in a system that would be stable in the case of a constant partition coefficient according to the classical stability conditions of Sternling and Scriven (AIChE J., 5, p.514, 1959).
Institute of Scientific and Technical Information of China (English)
Dilip Das
2015-01-01
There is a large class of problems in the field of fluid structure interaction where higher-order boundary conditions arise for a second-order partial differential equation. Various methods are being used to tackle these kind of mixed boundary-value problems associated with the Laplace’s equation (or Helmholtz equation) arising in the study of waves propagating through solids or fluids. One of the widely used methods in wave structure interaction is the multipole expansion method. This expansion involves a general combination of a regular wave, a wave source, a wave dipole and a regular wave-free part. The wave-free part can be further expanded in terms of wave-free multipoles which are termed as wave-free potentials. These are singular solutions of Laplace’s equation or two-dimensional Helmholz equation. Construction of these wave-free potentials and multipoles are presented here in a systematic manner for a number of situations such as two-dimensional non-oblique and oblique waves, three dimensional waves in two-layer fluid with free surface condition with higher order partial derivative are considered. In particular, these are obtained taking into account of the effect of the presence of surface tension at the free surface and also in the presence of an ice-cover modelled as a thin elastic plate. Also for limiting case, it can be shown that the multipoles and wave-free potential functions go over to the single layer multipoles and wave-free potential.
Goncharova, O. N.; Kabov, O. A.
2016-10-01
New physical experiments in the Institute of Thermophysics SB RAS allow one to investigate structure of the flows of liquid layers being under action of the co-current gas flux. The flow topology is determined by four main mechanisms: natural and thermocapillary convection, tangential stresses induced by the flow of gas and mass transfer due to evaporation at the interface. Mathematical modeling of the fluid flows in an infinite channel of the rectangular cross section is carried out on the basis of a solution of special type of the convection equations. The effects of thermodiffusion and diffusive thermal conductivity in the gas phase and evaporation at the thermocapillary interface are taken into consideration. Numerical investigations are performed for the liquid-gas (ethanol-nitrogen) system under normal and low gravity.
Controlled Release of Antimicrobial ClO2 Gas from a Two-Layer Polymeric Film System.
Bai, Zhifeng; Cristancho, Diego E; Rachford, Aaron A; Reder, Amy L; Williamson, Alexander; Grzesiak, Adam L
2016-11-16
We report a two-component label system comprising a chlorite-containing polymer film and an acid-containing polymer film that can release antimicrobial ClO2 gas upon adhering the two films together to enable a reaction of the chlorite and acid under moisture exposure. The chlorite-containing film comprises a commercial acrylate-based pressure-sensitive adhesive polymer impregnated with sodium chlorite. The acid-containing film comprises a commercial poly(vinyl alcohol) polymer loaded with tartaric acid. Both of the films were prepared on low ClO2-absorbing substrate films from stable aqueous systems of the polymers with high reagent loading. Rapid and sustained releases of significant amounts of ClO2 gas from the label system were observed in an in situ quantification system using UV-vis spectroscopy. It was found that the ClO2 release is slower at a lower temperature and can be accelerated by moisture in the atmosphere and the films. Controlled release of ClO2 gas from the label system was demonstrated by tailoring film composition and thickness. A model was developed to extract release kinetics and revealed good conversions of the label system. This two-component system can potentially be applied as a two-part label without premature release for applications in food packaging.
Energy Technology Data Exchange (ETDEWEB)
Willumsen, O.
1989-01-01
The aim of the project is to evaluate the performance of a new technique of installing earth coil systems for heat pumps. In order to reduce the costs of an efficient heat absorber, two coils were placed in the same trench in two different levels, generally in a depth of 0.7 and 1.1 metres. Usually the total pipe length was increased with 20 - 30% compared to the one-layer design. The digging expences, however, were still smaller than those of the one-layer design. The evaluation is based on measurements on 4 heat pump installations using the two-layer concept, where the extracted heat energy from the higher and lower earth coils were metered individually on a monthly basis. Furthermore, the in- and outlet temperature of the coils and the energy comsumption of the heat pump was measured. The main conclusions of the project are: - A two-layer design leads to a slightly cheaper earth coil. The performance of the earth coil is not negatively affected by this technique, provided that the vertical distance between the coils is at least 0.4 metres at any place. - Two-layer coils may be designed with the same total length as used in one-layer coils - which means half the trench length. This design gives a more intensive exploitation of the available soil area, without decreasing the performance of the heat pump. - The disadvantage of the technique is an increasing risk of earth elevation due to freezing. This risk should be minimized by keeping a minimum distance of 0.40 meters between the individual pipes and thermal insulation if more than two pipes are placed near to each other. (AB).
Budroni, M. A.; De Wit, A.
2016-06-01
When two solutions containing separate reactants A and B of an oscillating reaction are put in contact in a gel, localized spatiotemporal patterns can develop around the contact zone thanks to the interplay of reaction and diffusion processes. Using the Brusselator model, we explore analytically the deployment in space and time of the bifurcation diagram of such an A +B → oscillator system. We provide a parametric classification of possible instabilities as a function of the ratio of the initial reactant concentrations and of the reaction intermediate species diffusion coefficients. Related one-dimensional reaction-diffusion dynamics are studied numerically. We find that the system can spatially localize waves and Turing patterns as well as induce more complex dynamics such as zigzag spatiotemporal waves when Hopf and Turing modes interact.
Institute of Scientific and Technical Information of China (English)
Rong Liu; Qiusheng Liu
2006-01-01
Classical theories have successfully provided an explanation for convection in a liquid layer heated from below without evaporation.However,these theories are inadequate to account for the convective instabilities in an evaporating liquid layer,especially in the case when it is cooled from below.In the present paper,we study the onset of Marangoni convection in a liquid layer being overlain by a vapor layer.A new two-sided model is put forward instead of the one-sided in evaporating liquid thin layers are investigated with a linear instability analysis.We define a new evaporation Biot number,Which is different from that in previous studies and discuss the influences of reference evaporating velocity and evaporation Biot number on the vapor-liquid system.At the end,we explain why the instability occurs even when an evaporating liquid layer is cooled from below.
Directory of Open Access Journals (Sweden)
Kopáček Jaroslav
2016-01-01
Full Text Available This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element, which is seen as a random variable and their data (values can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.
Interfacial Stability in a Two-Layer Benard Problem.
1985-04-01
STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy Technical Summary Report #2814 April 1985 I cti- Work Unit Number 2 - Physical Mathematics...34•"• -••’-’• ^ ••’••• VI , •• W -•- • •- ’•"• INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy I. INTRODUCTION Two layers of fluids are...Subtltl») INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM 7. AUTMORf.; Yuriko Renardy »• PERFORMING ORGANIZATION NAME AND ADDRESS
Saha, Puspendu; Bose, Santanu; Mandal, Nibir
2016-10-01
Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges
DEFF Research Database (Denmark)
Probst, Christian W.; Hansen, Rene Rydhof
2009-01-01
Networked communication systems and the data they make available have, over the last decades, made their way to the very core of both society and business. Not only do they support everyday life and day-to-day operations, in many cases they enable them in the first place, and often are among...... security paradigm, that aims at using the network’s flexibility to move data and applications away from potential attackers. We also present a possible realization of the proposed paradigm, based on recent advances in language-based security and static analysis, where data and applications are partitioned...
DEFF Research Database (Denmark)
Probst, Christian W.; Hansen, René Rydhof
2009-01-01
Networked communication systems and the data they make available have, over the last decades, made their way to the very core of both society and business. Not only do they support everyday life and day-to-day operations, in many cases they enable them in the first place, and often are among...... security paradigm, that aims at using the network's flexibility to move data and applications away from potential attackers. We also present a possible realization of the proposed paradigm, based on recent advances in language-based security and static analysis, where data and applications are partitioned...
DEFF Research Database (Denmark)
Probst, Christian W.; Hansen, Rene Rydhof
2009-01-01
the most valuable assets. The flexibility that makes them so valuable in the first place, is also their primary vulnerability: via the network, an entity’s data is accessible from almost everywhere, often without the need of physical presence in the entity’s perimeter. In this work we propose a new...... security paradigm, that aims at using the network’s flexibility to move data and applications away from potential attackers. We also present a possible realization of the proposed paradigm, based on recent advances in language-based security and static analysis, where data and applications are partitioned......Networked communication systems and the data they make available have, over the last decades, made their way to the very core of both society and business. Not only do they support everyday life and day-to-day operations, in many cases they enable them in the first place, and often are among...
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.
Energy Technology Data Exchange (ETDEWEB)
Wang, Huhu, E-mail: huhuwang@tamu.edu [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Dominguez-Ontiveros, Elvis, E-mail: elvisdom@tamu.edu [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Hassan, Yassin A., E-mail: y-hassan@tamu.edu [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77840 (United States); Department of Mechanical Engineering, Texas A and M University, 3123 TAMU, College Station, TX 77840 (United States)
2014-03-15
Highlights: • A CFD model was built based on a two-layer block experimental facility at Texas A and M University. • The coolant characterizations within the uniform and wedge-shaped crossflow gap regions were investigated. • The influence on the coolant distribution from the bypass flow gap width was studied. • Discretization and iterative errors involved in the simulations were quantified. - Abstract: The very high temperature gas-cooled nuclear reactor (VHTR) has been designated as one of the promising reactors that will serve for the Next Generation (Generation IV) Nuclear Plant. For a prismatic VHTR core, the bypass flow and crossflow phenomena are important design considerations. To investigate the coolant distribution in the reactor core based on the two-layer block facility built at Texas A and M University, a three-dimensional steady-state CFD analysis was performed using the commercial code STAR-CCM+ v6.04. Results from this work serve as a guideline and validating source for the related experiments. A grid independence study was conducted to quantify related errors in the simulations. The simulation results show that the bypass flow fraction was not a strong function of the Reynolds number. The presence of the crossflow gap had a significant effect on the distribution of the coolant in the core. Uniform and wedge-shape crossflow gaps were studied. It was found that a significant secondary flow in the crossflow gap region moved from the bypass flow gap toward coolant holes, which resulted in up to a 28% reduction of the coolant mass flow rate in the bypass flow gap.
Theoretical Permeability of Two-layered Nonwoven Geotextiles
Institute of Scientific and Technical Information of China (English)
LIU Li-fang; CHU Cai-yuan
2006-01-01
The two-layered nonwoven geotextile, which consists of a layer constructed with fine fibers for providing optimal filtration characteristics and another layer constructed with coarse fibers for providing the required mechanical properties, is desirable for drainage and filtration system.Based on Darcy's law and drag force theory, a mathematical model on vertical permeability coefficient of two-layered nonwoven geotextile is estabilished. Comparison with experimental results shows that the present model possesses 83.6% accuracy for needle-punched two-layered nonwoven geotextiles. And experimental results also show that with the increasing of needle density the vertical permeability coefficient of two-layered nonwoven geotextiless firstly decreases and then increases, reaching the smallest value at 470 p/cm2.
Compressor bleed cooling fluid feed system
Donahoo, Eric E; Ross, Christopher W
2014-11-25
A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.
Two-Layer Quantum Key Distribution
Ramos, Rubens Viana
2012-01-01
Recently a new quantum key distribution protocol using coherent and thermal states was proposed. In this work this kind of two-layer QKD protocol is formalized and its security against the most common attacks, including external control and Trojan horse attacks, is discussed.
Introduction to thermo-fluids systems design
Garcia McDonald, André
2012-01-01
A fully comprehensive guide to thermal systems design covering fluid dynamics, thermodynamics, heat transfer and thermodynamic power cycles Bridging the gap between the fundamental concepts of fluid mechanics, heat transfer and thermodynamics, and the practical design of thermo-fluids components and systems, this textbook focuses on the design of internal fluid flow systems, coiled heat exchangers and performance analysis of power plant systems. The topics are arranged so that each builds upon the previous chapter to convey to the reader that topics are not stand-alone i
Directory of Open Access Journals (Sweden)
Andreev Vladimir Igorevich
2012-10-01
Full Text Available In the paper, the authors provide the results of analysis of a real construction facility performed with the help of a model of a two-layer beam of variable rigidity resting on the elastic bedding. The bottom layer of a two-layer beam simulates the foundation, the upper payer stands for the structure, and the weight of each layer is taken into consideration. The characteristics of the upper layer change alongside its length. Analytical and numerical methods of calculation were applied to solve this problem. The analytical solution is based on the method of initial parameters and backed by the practical data extracted from "Frame and Towerlike Buildings: Mattress Foundation Design Manual". According to the above manual, whenever the length-to-width ratio of a building exceeds 1.5, one-dimensional pattern composed of a composite beam resting on the elastic bedding may be used. The beam is divided into several sections, and deflection of each section is identified. It is equal to the settlements of the bedding surface. The rigidity change alongside the length of each section is assumed to be permanent, i.e. the beam is considered as the one that demonstrates its piecewise-constant rigidity. The following conclusion can be made on the basis of the calculations performed by the authors: the calculation of the «structure-foundation-bedding» system may require a simplified model representing composite beams and plates resting on the elastic bedding. More accurate models, such as sets of finite elements, are recommend for use in conjunction with simplified ones.
Novel Fluid Preservation System Project
National Aeronautics and Space Administration — To address NASA's need for a method to preserve blood and urine samples from astronauts collected during flight, Chromologic (CL) proposes to develop a novel Fluid...
Nonlinear topographic effects in two-layer flows
Directory of Open Access Journals (Sweden)
Peter George Baines
2016-02-01
Full Text Available We consider the nature of non-linear flow of a two-layer fluid with a rigid lid over a long obstacle, such that the flow may be assumed to be hydrostatic. Such flows can generate hydraulic jumps upstream, and the model uses a new model of internal hydraulic jumps, which results in corrections to flows that have been computed using earlier models of jumps that are now known to be incorrect. The model covers the whole range of ratios of the densities of the two fluids, and is not restricted to the Boussinesq limit. The results are presented in terms of flow types in various regions of a Froude number-obstacle height (F0 – Hm diagram, in which the Froude number F0 is based on the initial flow conditions. When compared with single-layer flow, and some previous results with two layers, some surprising and novel patterns emerge on these diagrams. Specifically, in parts of the diagram where the flow may be supercritical (F0 > 1, there are regions where hysteresis may occur, implying that the flow may have two and sometimes three multiple flow states for the same conditions (i.e. values of F0 and Hm.
Interacting Gauge-Fluid system
Banerjee, Rabin; Mitra, Arpan Krishna
2016-01-01
A gauge-fluid relativistic model where a non-isentropic fluid is coupled to a dynamical Maxwell ($U(1)$) gauge field, has been studied. We have examined in detail the structures of energy momentum tensor, derived from two definitions, {\\it{ie.}} the canonical (Noether) one and the symmetric one. In the conventional equal-time formalism, we have shown that the generators of the spacetime transformations obtained from these two definitions agree, modulo the Gauss constraint. This equivalence in the physical sector has been achieved only because of the dynamical nature of the gauge fields. Subsequently we have explicitly demonstrated the validity of the Schwinger condition. A detailed analysis of the model in lightcone formalism has also been done where several interesting features are revealed.
Surface cleanliness of fluid systems, specification for
1995-01-01
This specification establishes surface cleanliness levels, test methods, cleaning and packaging requirements, and protection and inspection procedures for determining surface cleanliness. These surfaces pertain to aerospace parts, components, assemblies, subsystems, and systems in contact with any fluid medium.
Fluid delivery manifolds and microfluidic systems
Energy Technology Data Exchange (ETDEWEB)
Renzi, Ronald F.; Sommer, Gregory J.; Singh, Anup K.; Hatch, Anson V.; Claudnic, Mark R.; Wang, Ying-Chih; Van de Vreugde, James L.
2017-02-28
Embodiments of fluid distribution manifolds, cartridges, and microfluidic systems are described herein. Fluid distribution manifolds may include an insert member and a manifold base and may define a substantially closed channel within the manifold when the insert member is press-fit into the base. Cartridges described herein may allow for simultaneous electrical and fluidic interconnection with an electrical multiplex board and may be held in place using magnetic attraction.
Reliable Fluid Power Pitch Systems
DEFF Research Database (Denmark)
Liniger, Jesper; Pedersen, Henrik Clemmensen; Soltani, Mohsen
2015-01-01
The key objectives of wind turbine manufactures and buyers are to reduce the Total Cost of Ownership and Total Cost of Energy. Among others, low downtime of a wind turbine is important to increase the amount of energy produced during its lifetime. Historical data indicate that pitch systems...
Central-Upwind Schemes for Two-Layer Shallow Water Equations
Kurganov, Alexander
2009-01-01
We derive a second-order semidiscrete central-upwind scheme for one- and two-dimensional systems of two-layer shallow water equations. We prove that the presented scheme is well-balanced in the sense that stationary steady-state solutions are exactly preserved by the scheme and positivity preserving; that is, the depth of each fluid layer is guaranteed to be nonnegative. We also propose a new technique for the treatment of the nonconservative products describing the momentum exchange between the layers. The performance of the proposed method is illustrated on a number of numerical examples, in which we successfully capture (quasi) steady-state solutions and propagating interfaces. © 2009 Society for Industrial and Applied Mathematics.
Interference testing of a two-layer commingled reservoir
Energy Technology Data Exchange (ETDEWEB)
Onur, M.; Reynolds, A.C. (Tulsa Univ., OK (USA))
1989-12-01
A two-well system in an infinite-acting, commingled, two-layer reservoir is considered. One well, the active well, is produced at a constant total rate, and the second well, the observation well, is shut in at all times. An analytical solution in Laplace space is presented, and the parametric groups that uniquely determine the pressure and rate solutions are identified. Results regarding crossflow through the observation well are presented. Conditions under which the line-source solution can be used to analyze observations-well pressure data are delineated.
Fluid structure interaction in piping systems
Energy Technology Data Exchange (ETDEWEB)
Svingen, Bjoernar
1996-12-31
The Dr. ing. thesis relates to an analysis of fluid structure interaction in piping systems in the frequency domain. The governing equations are the water hammer equations for the liquid, and the beam-equations for the structure. The fluid and structural equations are coupled through axial stresses and fluid continuity relations controlled by the contraction factor (Poisson coupling), and continuity and force relations at the boundaries (junction coupling). A computer program has been developed using the finite element method as a discretization technique both for the fluid and for the structure. This is made for permitting analyses of large systems including branches and loops, as well as including hydraulic piping components, and experiments are executed. Excitations are made in a frequency range from zero Hz and up to at least one thousand Hz. Frequency dependent friction is modelled as stiffness proportional Rayleigh damping both for the fluid and for the structure. With respect to the water hammer equations, stiffness proportional damping is seen as an artificial (bulk) viscosity term. A physical interpretation of this term in relation to transient/oscillating hydraulic pipe-friction is given. 77 refs., 72 figs., 4 tabs.
Fluid biomarkers in multiple system atrophy
DEFF Research Database (Denmark)
Laurens, Brice; Constantinescu, Radu; Freeman, Roy
2015-01-01
Despite growing research efforts, no reliable biomarker currently exists for the diagnosis and prognosis of multiple system atrophy (MSA). Such biomarkers are urgently needed to improve diagnostic accuracy, prognostic guidance and also to serve as efficacy measures or surrogates of target...... engagement for future clinical trials. We here review candidate fluid biomarkers for MSA and provide considerations for further developments and harmonization of standard operating procedures. A PubMed search was performed until April 24, 2015 to review the literature with regard to candidate blood...... and cerebrospinal fluid (CSF) biomarkers for MSA. Abstracts of 1760 studies were retrieved and screened for eligibility. The final list included 60 studies assessing fluid biomarkers in patients with MSA. Most studies have focused on alpha-synuclein, markers of axonal degeneration or catecholamines. Their results...
Drilling Fluid System & Technology in Sichuan Gas Field
Institute of Scientific and Technical Information of China (English)
Wang You; He Lun
1995-01-01
@@ Polymer Drilling FluidSystem SPA (Sichuan Petroleum Administration) began to use non-dispersed polymer drilling fluids in 1975. In the beginning,SPA adopted the single polymer drilling fluid systems utilizing single polyacrylamide as full flocculants or utilizing PHPA (partially hydrolyzed polyacrylamide) as proper flocculants, then SPA widely popularized the multi-polymer drilling fluid systems compounding of high, medium and low molecular weight polymers. The amphoteric polymers drilling fluid has been successfully developed and applied in recent years.
Studies of complexity in fluid systems
Energy Technology Data Exchange (ETDEWEB)
Kadanoff, L.P.; Constantin, P.; Dupont, T.F.; Nagel, S.
1993-02-01
Objective is to bring together researchers from several disciplines (mathematics, numerical computation, theoretical and experimental physics) who share an interest in the development of complexity in fluid systems. Work is in progress on development of singular interfluid interfaces on several fronts. Striking variations in droplet formation can be observed in physical experiments and simulations based on simple models. High-speed photographs are being taken of small liquid drop breaking into droplets. Experimental studies of granular materials are being continued.
Lie symmetry analysis and exact solutions of the quasi-geostrophic two-layer problem
Bihlo, Alexander
2010-01-01
The quasi-geostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximum Lie invariance algebra is constructed. On the basis of these subalgebras we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Where possible, reference to the physical meaning of the exact solutions is given.
Dynamics and flow-coupling in two-layer turbulent thermal convection
Xie, Yi-Chao
2015-01-01
We present an experimental investigation of the dynamics and flow-coupling of convective turbulent flows in a cylindrical Rayleigh-Benard convection cell with two immiscible fluids, water and fluorinert FC-77 electronic liquid (FC77). It is found that one large-scale circulation (LSC) roll exists in each of the fluid layers, and that their circulation planes have two preferred azimuthal orientations separated by $\\sim\\pi$. A surprising finding of the study is that cessations/reversals of the LSC in FC77 of the two-layer system occur much more frequently than they do in single-layer turbulent RBC, and that a cessation is most likely to result in a flow reversal of the LSC, which is in sharp contrast with the uniform distribution of the orientational angular change of the LSC before and after cessations in single-layer turbulent RBC. This implies that the dynamics governing cessations and reversals in the two systems are very different. Two coupling modes, thermal coupling (flow directions of the two LSCs are o...
Reducing pressure oscillations in discrete fluid power systems
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen
2016-01-01
Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article...
Lie symmetry analysis and exact solutions of the quasigeostrophic two-layer problem
Bihlo, Alexander; Popovych, Roman O.
2011-03-01
The quasigeostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximal Lie invariance algebra is constructed. On the basis of these subalgebras, we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Wherever possible, reference to the physical meaning of the exact solutions is given. In particular, the well-known baroclinic Rossby wave solutions in the two-layer model are rediscovered.
Wave scattering by undulating bed topography in a two-layer ocean
Institute of Scientific and Technical Information of China (English)
P. MAITI; B. N. MANDAL; U. BASU
2009-01-01
The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.
Random Boundary Simulation of Pumping Groundwater on Two-layer Soft Soil Structure with Porous Media
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Based on random theory,fluid dynamics,porous media and soil mechanics,the porosity and random characteristic of the two-layer soft soil in Wuhan region were studied in this paper.The random seepage coefficient on the two-layer soft soil was analyzed,and the seepage model and its random distribution function were given.The groundwater flow differential equations related to the two layer soft soil structure were also established.The evaluation procedure of effect boundary on the pumping water in deep foundation pit was put forward.Moreover,with an engineering example,the probability distribution on random boundary prediction for pumping water of foundation pit was computed.
Fluid flow dynamics in MAS systems.
Wilhelm, Dirk; Purea, Armin; Engelke, Frank
2015-08-01
The turbine system and the radial bearing of a high performance magic angle spinning (MAS) probe with 1.3mm-rotor diameter has been analyzed for spinning rates up to 67kHz. We focused mainly on the fluid flow properties of the MAS system. Therefore, computational fluid dynamics (CFD) simulations and fluid measurements of the turbine and the radial bearings have been performed. CFD simulation and measurement results of the 1.3mm-MAS rotor system show relatively low efficiency (about 25%) compared to standard turbo machines outside the realm of MAS. However, in particular, MAS turbines are mainly optimized for speed and stability instead of efficiency. We have compared MAS systems for rotor diameter of 1.3-7mm converted to dimensionless values with classical turbomachinery systems showing that the operation parameters (rotor diameter, inlet mass flow, spinning rate) are in the favorable range. This dimensionless analysis also supports radial turbines for low speed MAS probes and diagonal turbines for high speed MAS probes. Consequently, a change from Pelton type MAS turbines to diagonal turbines might be worth considering for high speed applications. CFD simulations of the radial bearings have been compared with basic theoretical values proposing considerably smaller frictional loss values. The discrepancies might be due to the simple linear flow profile employed for the theoretical model. Frictional losses generated inside the radial bearings result in undesired heat-up of the rotor. The rotor surface temperature distribution computed by CFD simulations show a large temperature gradient over the rotor.
Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach
Camassa, R; Ortenzi, G
2015-01-01
The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite 2D channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids' inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, and thence, in a non-trivial way, to the dispersionless non-linear Schr\\"odinger equation. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, it is shown that at first order the deformed system possesses an infinite sequence of constants of the motion, thus casting this system within the framework of comp...
Two layer asymptotic model for the wave propagation in the presence of vorticity
Kazakova, M. Yu; Noble, P.
2016-06-01
In the present study, we consider the system of two layers of the immiscible constant density fluids which are modeled by the full Euler equations. The domain of the flow is infinite in the horizontal directions and delimited above by a free surface. Bottom topography is taken into account. This is a simple model of the wave propagation in the ocean where the upper layer corresponds to the (thin) layer of fluid above the thermocline whereas the lower layer is under the thermocline. Though even this simple framework is computationally too expensive and mathematically too complicated to describe efficiently propagation of waves in the ocean. Modeling assumption such as shallowness, vanishing vorticity and hydrostatic pressure are usually made to get the bi-layer shallow water models that are mathematically more manageable. Though, they cannot describe correctly the propagation of both internal and free surface waves and dispersive/non hydrostatic must be added. Our goal is to consider the regime of medium to large vorticities in shallow water flow. We present the derivation of the model for internal and surface wave propagation in the case of constant and general vorticities in each layer. The model reduces to the classical Green-Naghdi equations in the case of vanishing vorticities.
Complex Fluids in Energy Dissipating Systems
Directory of Open Access Journals (Sweden)
Francisco J. Galindo-Rosales
2016-07-01
Full Text Available The development of engineered systems for energy dissipation (or absorption during impacts or vibrations is an increasing need in our society, mainly for human protection applications, but also for ensuring the right performance of different sort of devices, facilities or installations. In the last decade, new energy dissipating composites based on the use of certain complex fluids have flourished, due to their non-linear relationship between stress and strain rate depending on the flow/field configuration. This manuscript intends to review the different approaches reported in the literature, analyses the fundamental physics behind them and assess their pros and cons from the perspective of their practical applications.
A modular system for computational fluid dynamics
McCarthy, D. R.; Foutch, D. W.; Shurtleff, G. E.
This paper describes the Modular System for Compuational Fluid Dynamics (MOSYS), a software facility for the construction and execution of arbitrary solution procedures on multizone, structured body-fitted grids. It focuses on the structure and capabilities of MOSYS and the philosophy underlying its design. The system offers different levels of capability depending on the objectives of the user. It enables the applications engineer to quickly apply a variety of methods to geometrically complex problems. The methods developer can implement new algorithms in a simple form, and immediately apply them to problems of both theoretical and practical interest. And for the code builder it consitutes a toolkit for fast construction of CFD codes tailored to various purposes. These capabilities are illustrated through applications to a particularly complex problem encountered in aircraft propulsion systems, namely, the analysis of a landing aircraft in reverse thrust.
Phase transitions in fluids and biological systems
Sipos, Maksim
In this thesis, I consider systems from two seemingly different fields: fluid dynamics and microbial ecology. In these systems, the unifying features are the existences of global non-equilibrium steady states. I consider generic and statistical models for transitions between these global states, and I relate the model results with experimental data. A theme of this thesis is that these rather simple, minimal models are able to capture a lot of functional detail about complex dynamical systems. In Part I, I consider the transition between laminar and turbulent flow. I find that quantitative and qualitative features of pipe flow experiments, the superexponential lifetime and the splitting of turbulent puffs, and the growth rate of turbulent slugs, can all be explained by a coarse-grained, phenomenological model in the directed percolation universality class. To relate this critical phenomena approach closer to the fluid dynamics, I consider the transition to turbulence in the Burgers equation, a simplified model for Navier-Stokes equations. Via a transformation to a model of directed polymers in a random medium, I find that the transition to Burgers turbulence may also be in the directed percolation universality class. This evidence implies that the turbulent-to-laminar transition is statistical in nature and does not depend on details of the Navier-Stokes equations describing the fluid flow. In Part II, I consider the disparate subject of microbial ecology where the complex interactions within microbial ecosystems produce observable patterns in microbe abundance, diversity and genotype. In order to be able to study these patterns, I develop a bioinformatics pipeline to multiply align and quickly cluster large microbial metagenomics datasets. I also develop a novel metric that quantifies the degree of interactions underlying the assembly of a microbial ecosystem, particularly the transition between neutral (random) and niche (deterministic) assembly. I apply this
A flexible micro fluid transport system featuring magnetorheological elastomer
Behrooz, Majid; Gordaninejad, Faramarz
2016-02-01
This study presents a flexible magnetically-actuated micro fluid transport system utilizing an isotropic magnetorheological elastomer (MRE). Theoretical modeling and analysis of this system is presented for a two-dimensional model. This fluid transport system can propel the fluid by applying a fluctuating magnetic field on the MRE. The magneto-fluid-structure interaction analysis is employed to determine movement of the solid domain and the velocity of the fluid under a controllable magnetic field. The effects of key material, geometric, and magnetic parameters on the behavior of this system are examined. It is demonstrated that the proposed system can propel the fluid unidirectionally, and the volume of the transported fluid is significantly affected by some of the design parameters.
Heat transfer fluids for solar DHW systems
Energy Technology Data Exchange (ETDEWEB)
Wedel, S.; Bezzel, E.
2000-07-01
The aim of this work was to investigate the sudden clogging of the pipes in collectors as a consequence of liquid deterioration after repeated boiling during stagnation. A method to perform simple screening as accelerated tests of a large number liquid of samples subjected to various chemical- and physical environments have been designed. The acceleration factor of experiments relative to real systems is quite substantial primarily due to the extensive stress cycles in tests. Possible degradation mechanisms have been investigated and generally, there are two different paths to degradation of glycol: Thermal degradation and oxidative degradation primarily yielding propylene derivatives and carboxylic acids respectively. Polymerisation is an obvious possibility in a system containing various organic compounds such as acids and alcohols. Consequently, the reaction patterns alter making room for alternative interconnected mechanisms thus generating a broad spectrum of possible degradation products. Reserve alkalinity and pH are somewhat unreliable means of solely estimating the state of a liquid in relation to degradation and precipitation, as curvature of the RA-pH relations are different from liquid to liquid. For the majority of liquids, precipitation is not correlated with pH and RA. Coloration and precipitation in the liquid phase during stagnation separated liquids in two sub-categories. Fluids with inhibitor have sparing to moderate sedimentation and are brownish-black due to deterioration. Glycols without additives were either pale or colourless and did not precipitate. During normal operation, all fluids are clear and transparent and the majority has the same initial colour. The same distinction in liquids was observed on examination on the inside surface of the tubes concerning extent and the quantity of deposit. Liquids with additives tend to have significantly more deposit covering a larger surface than liquids without. Visual evaluation has proved that
Tracing Injection Fluids in Engineered Geothermal Systems
Rose, P. E.; Leecaster, K.; Mella, M.; Ayling, B.; Bartl, M. H.
2011-12-01
The reinjection of produced fluids is crucial to the effective management of geothermal reservoirs, since it provides a mechanism for maintaining reservoir pressures while allowing for the disposal of a toxic byproduct. Tracers are essential to the proper location of injection wells since they are the only known tool for reliably characterizing the flow patterns of recirculated fluids. If injection wells are placed too close to production wells, then reinjected fluids do not have sufficient residence time to extract heat from the reservoir and premature thermal breakthrough results. If injection wells are placed too far away, then the reservoir risks unacceptable pressure loss. Several thermally stable compounds from a family of very detectable fluorescent organic compounds (the naphthalene sulfonates) were characterized and found to be effective for use as geothermal tracers. Through batch-autoclave reactions, their Arrhenius pseudo-first-order decay-rate constants were determined. An analytical method was developed that allows for the laboratory determination of concentrations in the low parts-per-trillion range. Field experiments in numerous geothermal reservoirs throughout the world have confirmed the laboratory findings. Whereas conservative tracers such as the naphthalene sulfonates are effective tools for indicating interwell flow patterns and for measuring reservoir pore volumes, 'reactive' tracers can be used to constrain fracture surface area, which is the effective area for heat extraction. This is especially important for engineered geothermal system (EGS) wells, since reactive tracers can be used to measure fracture surface area immediately after drilling and while the well stimulation equipment is still on site. The reactive properties of these tracers that can be exploited to constrain fracture surface area are reversible sorption, contrasting diffusivity, and thermal decay. Laboratory batch- and flow-reactor experiments in combination with numerical
Studies of complexity in fluid systems
Energy Technology Data Exchange (ETDEWEB)
Nagel, Sidney R.
2000-06-12
This is the final report of Grant DE-FG02-92ER25119, ''Studies of Complexity in Fluids'', we have investigated turbulence, flow in granular materials, singularities in evolution of fluid surfaces and selective withdrawal fluid flows. We have studied numerical methods for dealing with complex phenomena, and done simulations on the formation of river networks. We have also studied contact-line deposition that occurs in a drying drop.
14 CFR 23.1097 - Carburetor deicing fluid system capacity.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor deicing fluid system capacity... Powerplant Induction System § 23.1097 Carburetor deicing fluid system capacity. (a) The capacity of each... operation. (b) If the available preheat exceeds 50 °F. but is less than 100 °F., the capacity of the...
SINFAC - SYSTEMS IMPROVED NUMERICAL FLUIDS ANALYSIS CODE
Costello, F. A.
1994-01-01
The Systems Improved Numerical Fluids Analysis Code, SINFAC, consists of additional routines added to the April 1983 revision of SINDA, a general thermal analyzer program. The purpose of the additional routines is to allow for the modeling of active heat transfer loops. The modeler can simulate the steady-state and pseudo-transient operations of 16 different heat transfer loop components including radiators, evaporators, condensers, mechanical pumps, reservoirs and many types of valves and fittings. In addition, the program contains a property analysis routine that can be used to compute the thermodynamic properties of 20 different refrigerants. SINFAC can simulate the response to transient boundary conditions. SINFAC was first developed as a method for computing the steady-state performance of two phase systems. It was then modified using CNFRWD, SINDA's explicit time-integration scheme, to accommodate transient thermal models. However, SINFAC cannot simulate pressure drops due to time-dependent fluid acceleration, transient boil-out, or transient fill-up, except in the accumulator. SINFAC also requires the user to be familiar with SINDA. The solution procedure used by SINFAC is similar to that which an engineer would use to solve a system manually. The solution to a system requires the determination of all of the outlet conditions of each component such as the flow rate, pressure, and enthalpy. To obtain these values, the user first estimates the inlet conditions to the first component of the system, then computes the outlet conditions from the data supplied by the manufacturer of the first component. The user then estimates the temperature at the outlet of the third component and computes the corresponding flow resistance of the second component. With the flow resistance of the second component, the user computes the conditions down stream, namely the inlet conditions of the third. The computations follow for the rest of the system, back to the first component
AFFECTION OF ER FLUID ON STIFFNESS OF VIBRATION SYSTEM
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
On the application of an electric field, the mechanical properties of ER(Electro-rheological) fluid are very complex. The damping force of ER fluid is linear without electric field and is nonlinear when an electric field is applied. By increasing the strength of the electric field, the behavior of ER fluid changes from linear viscous to nonlinear viscoelastic-plastic. External electric fluid changes natural behavior of system with ER fluid besides the mechanical properties of ER fluid. The affect of ER fluid on the stiffness of nonlinear vibration system with ER dampers is analyzed by iterative perturbation method. The results show that the stiffness of structure would be increased with growing of the strength of the electric field.
Controlled differential pressure system for an enhanced fluid blending apparatus
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.
Fluid Mechanics of Liquid-Liquid Systems.
Richards, John Reed
The detailed hydrodynamics of selected liquid -liquid flow systems are investigated to provide a firm foundation for the rational design of separation processes. The implementation of this objective centers on the development of a robust code to simulate liquid-liquid flows. We have applied this code to the realistic simulation of aspects of the complex fluid mechanical behavior, and developed quantitative insight into the underlying processes involved. The Volume of Fluid (VOF) method is combined with the Continuous Surface Force (CSF) algorithm to provide a numerically stable code capable of solving high Reynolds numbers free surface flows. One of the developments during the testing was an efficient method for solving the Young-Laplace equation describing the shape of the meniscus in a vertical cylinder for a constrained liquid volume. The steady-state region near the nozzle for the laminar flow of a Newtonian liquid jet injected vertically into another immiscible Newtonian liquid is investigated for various Reynolds numbers by solving the axisymmetric transient equations of motion and continuity. The analysis takes into account pressure, viscous, inertial, gravitational, and surface tension forces, and comparison with previous experimental measurements shows good agreement. Comparisons of the present numerical method with the numerical results of previous boundary-layer methods help establish their range of validity. A new approximate equation for the shape of the interface of the steady jet, based on an overall momentum balance, is also developed. The full transient from liquid-liquid jet startup to breakup into drops is also simulated numerically. In comparison with experiment, the results of the present numerical method show a greater sensitivity of the jet length to the Reynolds number than the best predictions of previous linear stability analyses. The formation of drops is investigated at low to high Reynolds numbers before and after jet formation. The
Improved efficient routing strategy on two-layer complex networks
Ma, Jinlong; Han, Weizhan; Guo, Qing; Zhang, Shuai; Wang, Junfang; Wang, Zhihao
2016-10-01
The traffic dynamics of multi-layer networks has become a hot research topic since many networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the traditional shortest path routing (SPR) protocol is susceptible to congestion on two-layer complex networks. In this paper, we propose an efficient routing strategy named improved global awareness routing (IGAR) strategy which is based on the betweenness centrality of nodes in the two layers. With the proposed strategy, the routing paths can bypass hub nodes of both layers to enhance the transport efficiency. Simulation results show that the IGAR strategy can bring much better traffic capacity than the SPR and the global awareness routing (GAR) strategies. Because of the significantly improved traffic performance, this study is helpful to alleviate congestion of the two-layer complex networks.
Nonlinear dynamics at the interface of two-layer stratified flows over pronounced obstacles
Cabeza, C; Bove, I; Freire, D; Marti, Arturo C; Sarasua, L G; Usera, G; Montagne, R; Araújo, M
2008-01-01
The flow of a two--layer stratified fluid over an abrupt topographic obstacle, simulating relevant situations in oceanographic problems, is investigated numerically and experimentally in a simplified two--dimensional situation. Experimental results and numerical simulations are presented at low Froude numbers in a two-layer stratified flow and for two abrupt obstacles, semi--cylindrical and prismatic. We find four different regimes of the flow immediately past the obstacles: sub-critical (I), internal hydraulic jump (II), Kelvin-Helmholtz at the interface (III) and shedding of billows (IV). The critical condition for delimiting the experiments is obtained using the hydraulic theory. Moreover, the dependence of the critical Froude number on the geometry of the obstacle are investigated. The transition from regime III to regime IV is explained with a theoretical stability analysis. The results from the stability analysis are confirmed with the DPIV measurements. In regime (IV), when the velocity upstream is lar...
Fluid Analysis of Network Content Dissemination and Cloud Systems
2017-03-06
Final 3. DATES COVERED (From - To) 01 Sep 2015 to 30 Nov 2016 4. TITLE AND SUBTITLE Fluid analysis of network content dissemination and cloud systems...2015 to 30 Nov 2016 AFOSR GRANT NUMBER: FA9550-15-1-0183 TITLE: Fluid analysis of network content dissemination and cloud systems PI: Fernando
Synchronization of Stochastic Two-Layer Geophysical Flows
Institute of Scientific and Technical Information of China (English)
HAN Yongqian
2011-01-01
In this paper, the two-layer quasigeostrophic flow model under stochastic wind forcing is considered. It is shown that when the layer depth or density difference across the layers tends to zero, the dynamics on both layers synchronizes to an averaged geophysical flow model.
Statistical mechanics of homogeneous partly pinned fluid systems.
Krakoviack, Vincent
2010-12-01
The homogeneous partly pinned fluid systems are simple models of a fluid confined in a disordered porous matrix obtained by arresting randomly chosen particles in a one-component bulk fluid or one of the two components of a binary mixture. In this paper, their configurational properties are investigated. It is shown that a peculiar complementarity exists between the mobile and immobile phases, which originates from the fact that the solid is prepared in presence of and in equilibrium with the adsorbed fluid. Simple identities follow, which connect different types of configurational averages, either relative to the fluid-matrix system or to the bulk fluid from which it is prepared. Crucial simplifications result for the computation of important structural quantities, both in computer simulations and in theoretical approaches. Finally, possible applications of the model in the field of dynamics in confinement or in strongly asymmetric mixtures are suggested.
A two-layered approach to recognize high-level human activities
N. Hu; G. Englebienne; B. Kröse
2014-01-01
Automated human activity recognition is an essential task for Human Robot Interaction (HRI). A successful activity recognition system enables an assistant robot to provide precise services. In this paper, we present a two-layered approach that can recognize sub-level activities and high-level activi
Institute of Scientific and Technical Information of China (English)
胡鹏飞; 林志勇; 周月宾; 江道灼; 梁一桥
2014-01-01
In high-voltage and large-power applications,the number of sub-modules in large-scale modular multilevel converters (MMCs) is huge,which makes the control system hardware design complicated and coordinated control difficult.In order to solve this problem,a control system consisting of one central control unit and several arm control units is proposed.Each arm control unit,in turn,consists of several valve-group control units,each of which j ust controls a few sub-modules.With the tasks of the central control unit and arm control units effectively reduced,the distributed control system is easily implemented and extended.In view of the proposed distributed control system with multiple control units,a new voltage-balancing method is divided into two parts,i.e.the intervalve-group voltage balance and the intravalve-group voltage balance.Finally,a three-phase 41-level MMC prototype is designed to verify the proposed control system and the voltage balancing method.It is shown by experimental results that the proposed control system is feasible and the proposed voltage balancing method is valid.%在高压大功率应用场合，模块化多电平换流器(MMC )每个桥臂子模块数量较多，造成其控制系统硬件构成复杂、协调控制困难。文中提出一种适用于大规模 MMC 的模块化结构的分布式控制系统：该控制系统由一个主控制单元和若干个桥臂控制单元构成，每个桥臂控制单元又由若干个阀组控制单元组成，每个阀组控制单元只控制较少数量的子模块。该结构有效降低了主控制单元和桥臂控制单元的控制压力，易于实现与扩展。针对该控制系统，提出一种包含阀组间均压和阀组内均压的新型均压策略。在三相41电平MMC实验样机上对所提出的控制系统及均压策略进行了验证，实验结果证明了所述控制系统的可行性及均压策略的有效性。
Numerical Modeling of Fluid Transient in Cryogenic Fluid Network of Rocket Propulsion System
Majumdar, Alok; Flachbart, Robin
2003-01-01
Fluid transients, also known as water hammer, can have a significant impact on the design and operation of both spacecraft and launch vehicles propulsion systems. These transients often occur at system activation and shut down. For ground safety reasons, many spacecrafts are launched with the propellant lines dry. These lines are often evacuated by the time the spacecraft reaches orbit. When the propellant isolation valve opens during propulsion system activation, propellant rushes into lines creating a pressure surge. During propellant system shutdown, a pressure surge is created due to sudden closure of a valve. During both activation and shutdown, pressure surges must be predicted accurately to ensure structural integrity of the propulsion system fluid network. The method of characteristics is the most widely used method of calculating fluid transients in pipeline [ 1,2]. The method of characteristics, however, has limited applications in calculating flow distribution in complex flow circuits with phase change, heat transfer and rotational effects. A robust cryogenic propulsion system analyzer must have the capability to handle phase change, heat transfer, chemical reaction, rotational effects and fluid transients in conjunction with subsystem flow model for pumps, valves and various pipe fittings. In recent years, such a task has been undertaken at Marshall Space Flight Center with the development of the Generalized Fluid System Simulation Program (GFSSP), which is based on finite volume method in fluid network [3]. GFSSP has been extensively verified and validated by comparing its predictions with test data and other numerical methods for various applications such as internal flow of turbo-pump [4], propellant tank pressurization [5,6], chilldown of cryogenic transfer line [7] and squeeze film damper rotordynamics [8]. The purpose of the present paper is to investigate the applicability of the finite volume method to predict fluid transient in cryogenic flow
Fluid Mud in Energetic Systems: FLUMES II
2014-09-30
demonstrated for fluid mud on the Amazon Shelf (Kineke and Sternberg , 1992). Disaggregated Inorganic Grain Size (DIGS) analysis for the suspended...the Petitcodiac River, New Brunswick, Canada. Masters Thesis, Boston College, Chestnut Hill, MA. 125 pp. Kineke, G.C. and R.W. Sternberg (1992
Methods and systems for integrating fluid dispensing technology with stereolithography
Energy Technology Data Exchange (ETDEWEB)
Medina, Francisco (El Paso, TX); Wicker, Ryan (El Paso, TX); Palmer, Jeremy A. (Albuquerque, NM); Davis, Don W. (Albuquerque, NM); Chavez, Bart D. (Albuquerque, NM); Gallegos, Phillip L. (Albuquerque, NM)
2010-02-09
An integrated system and method of integrating fluid dispensing technologies (e.g., direct-write (DW)) with rapid prototyping (RP) technologies (e.g., stereolithography (SL)) without part registration comprising: an SL apparatus and a fluid dispensing apparatus further comprising a translation mechanism adapted to translate the fluid dispensing apparatus along the Z-, Y- and Z-axes. The fluid dispensing apparatus comprises: a pressurized fluid container; a valve mechanism adapted to control the flow of fluid from the pressurized fluid container; and a dispensing nozzle adapted to deposit the fluid in a desired location. To aid in calibration, the integrated system includes a laser sensor and a mechanical switch. The method further comprises building a second part layer on top of the fluid deposits and optionally accommodating multi-layered circuitry by incorporating a connector trace. Thus, the present invention is capable of efficiently building single and multi-material SL fabricated parts embedded with complex three-dimensional circuitry using DW.
Pattern Synchronization in a Two-Layer Neuronal Network
Institute of Scientific and Technical Information of China (English)
SUN Xiao-Juan; LU Qi-Shao
2009-01-01
Pattern synchronization in a two-layer neuronal network is studied.For a single-layer network of Rulkov map neurons,there are three kinds of patterns induced by noise.Additive noise can induce ordered patterns at some intermediate noise intensities in a resonant way;however,for small and large noise intensities there exist excitable patterns and disordered patterns,respectively.For a neuronal network coupled by two single-layer networks with noise intensity differences between layers,we find that the two-layer network can achieve synchrony as the interlayer coupling strength increases.The synchronous states strongly depend on the interlayer coupling strength and the noise intensity difference between layers.
TWO-LAYER MODEL DESCRIPTION OF POLYMER THIN FILM DYNAMICS
Institute of Scientific and Technical Information of China (English)
Dong-dong Peng; Ran-xing Nancy Li; Chi-hang Lam; Ophelia K.C.Tsui
2013-01-01
Experiments in the past two decades have shown that the glass transition temperature of polymer films can become noticeably different from that of the bulk when the film thickness is decreased below ca.100 nm.It is broadly believed that these observations are caused by a nanometer interfacial layer with dynamics faster or slower than that of the bulk.In this paper,we examine how this idea may be realized by using a two-layer model assuming a hydrodynamic coupling between the interfacial layer and the remaining,bulk-like layer in the film.Illustrative examples will be given showing how the two-layer model is applied to the viscosity measurements of polystyrene and polymethylmethacrylate films supported by silicon oxide,where divergent thickness dependences are observed.
Training two-layered feedforward networks with variable projection method.
Kim, C T; Lee, J J
2008-02-01
The variable projection (VP) method for separable nonlinear least squares (SNLLS) is presented and incorporated into the Levenberg-Marquardt optimization algorithm for training two-layered feedforward neural networks. It is shown that the Jacobian of variable projected networks can be computed by simple modification of the backpropagation algorithm. The suggested algorithm is efficient compared to conventional techniques such as conventional Levenberg-Marquardt algorithm (LMA), hybrid gradient algorithm (HGA), and extreme learning machine (ELM).
Electromagnetic Scattering in a Two-layered Medium
Institute of Scientific and Technical Information of China (English)
FENG LI-XIN; LI YUAN; Ma Fu-ming
2011-01-01
The object of this paper is to investigate the three-dimensional electro-magnetic scattering problems in a two-layered background medium.These problems have an important application in today's technology,such as to detect objects that are buried in soil.Here,we model both the exterior impedance problem and the inhomogeneous medium problem in R3.We establish uniqueness and existence for the solution of the two scattering problems,respectively.
Majumdar, Alok; Leclair, Andre; Moore, Ric; Schallhorn, Paul
2011-01-01
GFSSP stands for Generalized Fluid System Simulation Program. It is a general-purpose computer program to compute pressure, temperature and flow distribution in a flow network. GFSSP calculates pressure, temperature, and concentrations at nodes and calculates flow rates through branches. It was primarily developed to analyze Internal Flow Analysis of a Turbopump Transient Flow Analysis of a Propulsion System. GFSSP development started in 1994 with an objective to provide a generalized and easy to use flow analysis tool for thermo-fluid systems.
Improvement and Progress of CARR Fluid Systems Design
Institute of Scientific and Technical Information of China (English)
2001-01-01
There are 18 fluid systems in CARR. They are respectively: the reactor coolant system(RCS); the secondary cooling water system; the heavy water cooling system; the secondary shutdown system; the helium system; the vacuum system; the warm-layer circulation system; the emergency core cooling system(ECCS); the isotope chamber water cooling system; the pool-water feed and drain system; the reactor coolant purification system; the reactor pool-water purification system; the heavy water purification system; the heavy water condense system; the intermediate-level waste
Institute of Scientific and Technical Information of China (English)
莫东鸣
2015-01-01
In order to understand the liquid layer depth ratio on the stability of two-layer system with upper rigid walls at the microgravity condition,a linear stability analysis of thermocapillary flow in the annular immiscible two-layer system of 5cSt silicone oil and HT-70 was carried out using Implicity Restarted Arnoldi Method (IRAM).Critical values of Marangoni number,wave number and phase velocity were obtained at different liquid layer depth ratios,different aspect ratios of the cavity and different radius rations.The thermofluid wave pattern at the liquid-liquid interface near the critical Marangoni number was also exhibited.%为了了解微重力条件下、水平温度梯度作用时，上部为固壁的环形腔内双层流体系统中液层厚度比对流动稳定性的影响，采用隐式重启 Arnoldi方法(IRAM)对环形池内5cSt 硅油/HT-70双层流体的热对流过程进行了线性稳定性分析，获得了不同液层厚度比下系统流动的临界 Marangoni 数、临界波数、临界相速度，并通过计算特征向量，得到了临界 Marangoni数附近液-液界面的热流体波形态。
Complex fluids in biological systems experiment, theory, and computation
2015-01-01
This book serves as an introduction to the continuum mechanics and mathematical modeling of complex fluids in living systems. The form and function of living systems are intimately tied to the nature of surrounding fluid environments, which commonly exhibit nonlinear and history dependent responses to forces and displacements. With ever-increasing capabilities in the visualization and manipulation of biological systems, research on the fundamental phenomena, models, measurements, and analysis of complex fluids has taken a number of exciting directions. In this book, many of the world’s foremost experts explore key topics such as: Macro- and micro-rheological techniques for measuring the material properties of complex biofluids and the subtleties of data interpretation Experimental observations and rheology of complex biological materials, including mucus, cell membranes, the cytoskeleton, and blood The motility of microorganisms in complex fluids and the dynamics of active suspensions Challenges and solut...
Ice Detector and Deicing Fluid Effectiveness Monitoring System
Seegmiller, H. Lee B. (Inventor)
1996-01-01
An ice detector and deicing fluid effectiveness monitoring system for an aircraft is disclosed. The ice detection portion is particularly suited for use in flight to notify the flight crew of an accumulation of ice on an aircraft lifting and control surfaces, or helicopter rotors, whereas the deicing fluid effectiveness monitoring portion is particularly suited for use on the ground to notify the flight crew of the possible loss of the effectiveness of the deicing fluid. The ice detection portion comprises a temperature sensor and a parallel arrangement of electrodes whose coefficient of coupling is indicative of the formation of the ice, as well as the thickness of the formed ice. The fluid effectiveness monitoring portion comprises a temperature sensor and an ionic-conduction cell array that measures the conductivity of the deicing fluid which is indicative of its concentration and, thus, its freezing point. By measuring the temperature and having knowledge of the freezing point of the deicing fluid, the fluid effectiveness monitoring portion predicts when the deicing fluid may lose its effectiveness because its freezing point may correspond to the temperature of the ambient.
Two-Layer Feedback Neural Networks with Associative Memories
Institute of Scientific and Technical Information of China (English)
WU Gui-Kun; ZHAO Hong
2008-01-01
We construct a two-layer feedback neural network by a Monte Carlo based algorithm to store memories as fixed-point attractors or as limit-cycle attractors. Special attention is focused on comparing the dynamics of the network with limit-cycle attractors and with fixed-point attractors. It is found that the former has better retrieval property than the latter. Particularly, spurious memories may be suppressed completely when the memories are stored as a long-limit cycle. Potential application of limit-cycle-attractor networks is discussed briefly.
Tidal modulation of two-layer hydraulic exchange flows
Directory of Open Access Journals (Sweden)
L. M. Frankcombe
2006-11-01
Full Text Available Time-dependent, two layer hydraulic exchange flow is studied using an idealised shallow water model. It is found that barotropic time-dependent perturbations, representing tidal forcing, increase the baroclinic exchange flux above the steady hydraulic limit, with flux increasing monotonically with tidal amplitude (measured either by height or flux amplitude over a tidal period. Exchange flux also depends on the non-dimensional tidal period, γ, which was introduced by Helfrich (1995. Resonance complicates the relationship between exchange flux and height amplitude, but, when tidal strength is characterised by flux amplitude, exchange flux is a monotonic function of γ.
Baroclinic instability in the two-layer model. Interpretations
Energy Technology Data Exchange (ETDEWEB)
Egger, Joseph [Meteorological Inst., Univ. of Munich (Germany)
2009-10-15
Two new interpretations of the wellknown instability criterion of the two-layer model of baroclinic instability are given whereby also a slight generalization of this model is introduced by admitting an interface on top with a reduced gravity g. It is found that instability sets in when the horizontal potential temperature advection by the barotropic mode becomes more important than the vertical temperature advection due to this mode. The second interpretation is based on potential vorticity (PV) thinking. Instability implies a dominance of the vertical PV coupling coefficient compared to horizontal mean state PV advection generated at the same level. The interface damps with decreasing g. (orig.)
Development of fluid and I and C systems design technology
Energy Technology Data Exchange (ETDEWEB)
Sim, Yoon Sub; Park, C. K.; Kim, S. O. [and others
2000-05-01
LMR is the reactor type that makes utilization of uranium resource very efficiently and the necessity of construction of a LMR in 2020's has been raised. However, the design technology required for construction has not been secured domestically. To fulfill the necessity, study has been made for the LMR system design technology and conceptual design of KALIMER systems for fluid, instrumentation, control, and protection have been developed. Also the computer code systems for the design and analysis of the KALIMER fluid systems have been developed. These study results are to used as the starting point of the next phase LMR design technology development research.
Towards a smart non-invasive fluid loss measurement system.
Suryadevara, N K; Mukhopadhyay, S C; Barrack, L
2015-04-01
In this article, a smart wireless sensing non-invasive system for estimating the amount of fluid loss, a person experiences while physical activity is presented. The system measures three external body parameters, Heart Rate, Galvanic Skin Response (GSR, or skin conductance), and Skin Temperature. These three parameters are entered into an empirically derived formula along with the user's body mass index, and estimation for the amount of fluid lost is determined. The core benefit of the developed system is the affluence usage in combining with smart home monitoring systems to care elderly people in ambient assisted living environments as well in automobiles to monitor the body parameters of a motorist.
Spatial frequency domain spectroscopy of two layer media
Yudovsky, Dmitry; Durkin, Anthony J.
2011-10-01
Monitoring of tissue blood volume and oxygen saturation using biomedical optics techniques has the potential to inform the assessment of tissue health, healing, and dysfunction. These quantities are typically estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in superficial tissue such as the skin can be confounded by the strong absorption of melanin in the epidermis. Furthermore, epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. This study describes a technique for decoupling the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. An artificial neural network was used to map input optical properties to spatial frequency domain diffuse reflectance of two layer media. Then, iterative fitting was used to determine the optical properties from simulated spatial frequency domain diffuse reflectance. Additionally, an artificial neural network was trained to directly map spatial frequency domain reflectance to sets of optical properties of a two layer medium, thus bypassing the need for iteration. In both cases, the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis were determined independently. The accuracy and efficiency of the iterative fitting approach was compared with the direct neural network inversion.
Two-Layer Elastographic 3-D Traction Force Microscopy
Álvarez-González, Begoña; Zhang, Shun; Gómez-González, Manuel; Meili, Ruedi; Firtel, Richard A.; Lasheras, Juan C.; Del Álamo, Juan C.
2017-01-01
Cellular traction force microscopy (TFM) requires knowledge of the mechanical properties of the substratum where the cells adhere to calculate cell-generated forces from measurements of substratum deformation. Polymer-based hydrogels are broadly used for TFM due to their linearly elastic behavior in the range of measured deformations. However, the calculated stresses, particularly their spatial patterns, can be highly sensitive to the substratum’s Poisson’s ratio. We present two-layer elastographic TFM (2LETFM), a method that allows for simultaneously measuring the Poisson’s ratio of the substratum while also determining the cell-generated forces. The new method exploits the analytical solution of the elastostatic equation and deformation measurements from two layers of the substratum. We perform an in silico analysis of 2LETFM concluding that this technique is robust with respect to TFM experimental parameters, and remains accurate even for noisy measurement data. We also provide experimental proof of principle of 2LETFM by simultaneously measuring the stresses exerted by migrating Physarum amoeboae on the surface of polyacrylamide substrata, and the Poisson’s ratio of the substrata. The 2LETFM method could be generalized to concurrently determine the mechanical properties and cell-generated forces in more physiologically relevant extracellular environments, opening new possibilities to study cell-matrix interactions.
Systems and methods for separating particles and/or substances from a sample fluid
Mariella, Jr., Raymond P.; Dougherty, George M.; Dzenitis, John M.; Miles, Robin R.; Clague, David S.
2016-11-01
Systems and methods for separating particles and/or toxins from a sample fluid. A method according to one embodiment comprises simultaneously passing a sample fluid and a buffer fluid through a chamber such that a fluidic interface is formed between the sample fluid and the buffer fluid as the fluids pass through the chamber, the sample fluid having particles of interest therein; applying a force to the fluids for urging the particles of interest to pass through the interface into the buffer fluid; and substantially separating the buffer fluid from the sample fluid.
Systems and methods for separating particles and/or substances from a sample fluid
Energy Technology Data Exchange (ETDEWEB)
Mariella, Jr., Raymond P.; Dougherty, George M.; Dzenitis, John M.; Miles, Robin R.; Clague, David S.
2016-11-01
Systems and methods for separating particles and/or toxins from a sample fluid. A method according to one embodiment comprises simultaneously passing a sample fluid and a buffer fluid through a chamber such that a fluidic interface is formed between the sample fluid and the buffer fluid as the fluids pass through the chamber, the sample fluid having particles of interest therein; applying a force to the fluids for urging the particles of interest to pass through the interface into the buffer fluid; and substantially separating the buffer fluid from the sample fluid.
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik C.
2014-01-01
Discrete fluid power technology attracts great attention because it enables energy efficiency and robust system architectures. However, the discrete nature of this technology naturally brings shifting phenomenons into the picture. For fluid power system the relative high inductance of fluid...
Fluid-filled blood pressure measurement systems.
Li, J K; van Brummelen, A G; Noordergraaf, A
1976-05-01
The performance of catheter-manometer systems for the measurement of pulsatile pressure has been evaluated by both experimental techniques and theoretical considerations. The former approach has shown, on occasion, multiple maxima in the amplitude response. The latter has been approached in a variety of ways, ranging from extreme lumping to application of transmission line theory while employing different configurations in the system's representation. Multiple maxima have also been seen, The present paper identifies the sources of the differences found and compares the relative merits of various theoretical approaches. It introduces the compliance of the system as a figure of merit and provides a simple first-order approximation formula for evaluation of the quality of a system. Damping and impedance matching to improve the system's frequency response were studied. It was found that they were not needed in a very stiff or a very compliant system, nor should one worry about the representation of such a system.
Development of hyperbolic solution method for two fluids equation system
Energy Technology Data Exchange (ETDEWEB)
Lee, Sung Jae; Chang, Won Pyo
1997-07-01
Using the concept of surface tension thickness, the mathematical ill-posedness of the two fluids equation system can now be removed by splitting the pressure discontinuity of the two fluids interface. The bulk modulus L1 and L2 derived from the concept of surface tension thickness makes two fluids equation system hyperbolic type. The hyperbolic equation system has five complete sets of eigenvectors, each of which having real eigenvalues. Three sets of them represents the propagation speeds of the physical properties for individual flow regimes such as the dispersed, the slug, and the separated flows. The propagation characteristics of these eigenvalues have good agreements with both the experimental data and other theoretical results in two-phase mixture. The feature of the hyperbolic model allows to apply advanced numerical upwind technique such as Flux vector splitting (FVS) method. The numerical test show that the characteristics of equation system clearly classify all flow regimes. (author). 25 refs., 3 tabs., 20 figs.
ISS-CREAM Thermal and Fluid System Design and Analysis
Thorpe, Rosemary S.
2015-01-01
Thermal and Fluids Analysis Workshop (TFAWS), Silver Spring MD NCTS 21070-15. The ISS-CREAM (Cosmic Ray Energetics And Mass for the International Space Station) payload is being developed by an international team and will provide significant cosmic ray characterization over a long time frame. Cold fluid provided by the ISS Exposed Facility (EF) is the primary means of cooling for 5 science instruments and over 7 electronics boxes. Thermal fluid integrated design and analysis was performed for CREAM using a Thermal Desktop model. This presentation will provide some specific design and modeling examples from the fluid cooling system, complex SCD (Silicon Charge Detector) and calorimeter hardware, and integrated payload and ISS level modeling. Features of Thermal Desktop such as CAD simplification, meshing of complex hardware, External References (Xrefs), and FloCAD modeling will be discussed.
Generalized Fluid System Simulation Program, Version 5.0-Educational
Majumdar, A. K.
2011-01-01
The Generalized Fluid System Simulation Program (GFSSP) is a finite-volume based general-purpose computer program for analyzing steady state and time-dependent flow rates, pressures, temperatures, and concentrations in a complex flow network. The program is capable of modeling real fluids with phase changes, compressibility, mixture thermodynamics, conjugate heat transfer between solid and fluid, fluid transients, pumps, compressors and external body forces such as gravity and centrifugal. The thermofluid system to be analyzed is discretized into nodes, branches, and conductors. The scalar properties such as pressure, temperature, and concentrations are calculated at nodes. Mass flow rates and heat transfer rates are computed in branches and conductors. The graphical user interface allows users to build their models using the point, drag and click method; the users can also run their models and post-process the results in the same environment. The integrated fluid library supplies thermodynamic and thermo-physical properties of 36 fluids and 21 different resistance/source options are provided for modeling momentum sources or sinks in the branches. This Technical Memorandum illustrates the application and verification of the code through 12 demonstrated example problems.
Nonstationary Axisymmetric Temperature Field in a Two-Layer Slab Under Mixed Heating Conditions
Turchin, I. N.; Timar, I.; Kolodii, Yu. A.
2015-09-01
With the use of the Laguerre and Hankel integral transforms, the solution of a two-dimensional initial-boundary-value heat conduction problem for a two-layer slab under mixed boundary conditions is constructed: one of the surfaces is heated by a heat flux distributed axisymmetrically in a circle of radius R and is cooled by the Newton law outside this circle. The solution of the problem is reduced to a sequence of infinite quasi-regular systems of algebraic equations. The results of numerical analysis of the temperature field in the two-layer slab made from an aluminum alloy and ceramicsare presented depending on the relative geometric properties of the components and cooling intensity.
Estimation of apparent soil resistivity for two-layer soil structure
Energy Technology Data Exchange (ETDEWEB)
Nassereddine, M.; Rizk, J.; Nagrial, M.; Hellany, A. [School of Computing, Engineering and Mathematics, University of Western Sydney (Australia)
2013-07-01
High voltage (HV) earthing design is one of the key elements when it comes to safety compliance of a system. High voltage infrastructure exposes workers and people to unsafe conditions. The soil structure plays a vital role in determining the allowable and actual step/touch voltage. This paper presents vital information when working with two-layer soil structure. It shows the process as to when it is acceptable to use a single layer instead of a two-layer structure. It also discusses the simplification of the soil structure approach depending on the reflection coefficient. It introduces the reflection coefficient K interval which determines if single layer approach is acceptable. Multiple case studies are presented to address the new approach and its accuracy.
A Generalized Fluid System Simulation Program to Model Flow Distribution in Fluid Networks
Majumdar, Alok; Bailey, John W.; Schallhorn, Paul; Steadman, Todd
1998-01-01
This paper describes a general purpose computer program for analyzing steady state and transient flow in a complex network. The program is capable of modeling phase changes, compressibility, mixture thermodynamics and external body forces such as gravity and centrifugal. The program's preprocessor allows the user to interactively develop a fluid network simulation consisting of nodes and branches. Mass, energy and specie conservation equations are solved at the nodes; the momentum conservation equations are solved in the branches. The program contains subroutines for computing "real fluid" thermodynamic and thermophysical properties for 33 fluids. The fluids are: helium, methane, neon, nitrogen, carbon monoxide, oxygen, argon, carbon dioxide, fluorine, hydrogen, parahydrogen, water, kerosene (RP-1), isobutane, butane, deuterium, ethane, ethylene, hydrogen sulfide, krypton, propane, xenon, R-11, R-12, R-22, R-32, R-123, R-124, R-125, R-134A, R-152A, nitrogen trifluoride and ammonia. The program also provides the options of using any incompressible fluid with constant density and viscosity or ideal gas. Seventeen different resistance/source options are provided for modeling momentum sources or sinks in the branches. These options include: pipe flow, flow through a restriction, non-circular duct, pipe flow with entrance and/or exit losses, thin sharp orifice, thick orifice, square edge reduction, square edge expansion, rotating annular duct, rotating radial duct, labyrinth seal, parallel plates, common fittings and valves, pump characteristics, pump power, valve with a given loss coefficient, and a Joule-Thompson device. The system of equations describing the fluid network is solved by a hybrid numerical method that is a combination of the Newton-Raphson and successive substitution methods. This paper also illustrates the application and verification of the code by comparison with Hardy Cross method for steady state flow and analytical solution for unsteady flow.
Preparation of drug delivery systems using supercritical fluid technology.
Kompella, U B; Koushik, K
2001-01-01
Small changes in temperature and pressure near the critical region induce dramatic changes in the density and solubility of supercritical fluids, thereby facilitating the use of environmentally benign agents such as CO2 for their solvent and antisolvent properties in processing a wide variety of materials. While supercritical fluid technologies have been in commercial use in the food and chromatography industries for several years, only recently has this technology made inroads in the formulation of drug delivery systems. This review summarizes some of the recent applications of supercritical fluid technology in the preparation of drug delivery systems. Drugs containing polymeric particles, plain drug particles, solute-containing liposomes, and inclusion complexes of drug and carrier have been formulated using this technology. Also, polymer separation using this technology is enabling the selection of a pure fraction of a polymer, thereby allowing a more precise control of drug release from polymeric delivery systems.
Systems and methods for multi-fluid geothermal energy systems
Energy Technology Data Exchange (ETDEWEB)
Buscheck, Thomas A.
2017-09-19
A method for extracting geothermal energy from a geothermal reservoir formation. A production well is used to extract brine from the reservoir formation. At least one of nitrogen (N.sub.2) and carbon dioxide (CO.sub.2) may be used to form a supplemental working fluid which may be injected into a supplemental working fluid injection well. The supplemental working fluid may be used to augment a pressure of the reservoir formation, to thus drive a flow of the brine out from the reservoir formation.
LHC II system sensitivity to magnetic fluids
Cotae, Vlad
2005-01-01
Experiments have been designed to reveal the influences of ferrofluid treatment and static magnetic field exposure on the photosynthetic system II, where the light harvesting complex (LHC II) controls the ratio chlorophyll a/ chlorophyll b (revealing, indirectly, the photosynthesis rate). Spectrophotometric measurement of chlorophyll content revealed different influences for relatively low ferrofluid concentrations (10-30 mul/l) in comparison to higher concentrations (70-100 mul/l). The overlapped effect of the static magnetic field shaped better the stimulatory ferrofluid action on LHC II system in young poppy plantlets.
A Dynamical System Analysis of Three Fluid cosmological Model
Mahata, Nilanjana
2015-01-01
In Friedman-Robertson-Walker flat spacetime, we consider a three fluid cosmological model which contains dark matter, dark energy and baryonic matter in the form of perfect fluid with a barotropic equation of state. Dark matter is taken in form of dust and dark energy is described by a scalar field with a potential $V(\\phi)$. Einstein's field equations are reduced to an autonomous dynamical system by suitable redefinition of basic variables. Considering exponential potential for the scalar field, critical points are obtained for the autonomous system. Finally stability of the critical points and cosmological implications are analyzed.
Process fluids of aero-hydraulic systems and their properties
Directory of Open Access Journals (Sweden)
I. S. Shumilov
2014-01-01
Full Text Available The article considers process fluids, which are presently applied to aviation hydraulic systems in domestic and world practice. Aviation practice deals with rather wide list of fluids. Based on the technical specification a designer makes the choice of specific fluid for the specific aircraft. Process fluids have to possess the specified properties presented in the article, namely: lubricating properties; stability of physical and chemical characteristics at operation and storage; lowtemperature properties; acceptable congelation temperature; compatibility with materials of units and components of hydraulic systems; heat conductivity; high rigidity; minimum low coefficient of volume expansion; fire-explosion safety; low density. They should also have good dielectric properties, be good to resist to destruction of molecules, have good anticorrosion and antierosion properties, as well as not create conditions for emerging electro-kinetic erosion of spooltype and other precision devices, and a number of other properties.The article presents materials on the oil-based process fluids with + (200-320 °C boiling temperature, gelled by a polymer of vinyl butyl ether, with aging inhibitor and dye for hydraulic systems of the subsonic and transonic aircraft which are combustible, with a temperature interval of use from — 60oС до +125oС. It also describes materials on process fluids, which are based on the mix of polydialkylsiloxane oligomers with organic diester aging inhibitors, and wear-resistant additive to be applied to the hydraulic systems of supersonic aircrafts using a fluid within the temperature interval from - 6О oС to +175oС for a long duration. The fire-explosion safety process fluids representing a mix of phosphoric esters with additives to improve viscous, anti-oxidizing, anticorrosive and anti-erosive properties are considered as well. They are used within the temperature range from - 60оС to +125оС with overheats up to +150
A two-layer optimization model for high-speed railway line planning
Institute of Scientific and Technical Information of China (English)
Li WANG; Li-min JIA; Yong QIN; Jie XU; Wen-ring MO
2011-01-01
Line planning is the first important strategic element in the railway operation planning process,which will directly affect the successive planning to determine the efficiency of the whole railway system.A two-layer optimization model is proposed within a simulation framework to deal with the high-speed railway (HSR) line planning problem.In the model,the top layer aims at achieving an optimal stop-schedule set with the service frequencies,and is formulated as a nonlinear program,solved by genetic algorithm.The objective of top layer is to minimize the total operation cost and unserved passenger volume.Given a specific stop-schedule,the bottom layer focuses on weighted passenger flow assignment,formulated as a mixed integer program with the objective of maximizing the served passenger volume and minimizing the total travel time for all passengers.The case study on Taiwan HSR shows that the proposed two-layer model is better than the existing techniques.In addition,this model is also illustrated with the Beijing-Shanghai HSR in China.The result shows that the two-layer optimization model can reduce computation complexity and that an optimal set of stop-schedules can always be generated with less calculation time.
Generalized Fluid System Simulation Program, Version 6.0
Majumdar, A. K.; LeClair, A. C.; Moore, R.; Schallhorn, P. A.
2016-01-01
The Generalized Fluid System Simulation Program (GFSSP) is a general purpose computer program for analyzing steady state and time-dependent flow rates, pressures, temperatures, and concentrations in a complex flow network. The program is capable of modeling real fluids with phase changes, compressibility, mixture thermodynamics, conjugate heat transfer between solid and fluid, fluid transients, pumps, compressors, and external body forces such as gravity and centrifugal. The thermofluid system to be analyzed is discretized into nodes, branches, and conductors. The scalar properties such as pressure, temperature, and concentrations are calculated at nodes. Mass flow rates and heat transfer rates are computed in branches and conductors. The graphical user interface allows users to build their models using the 'point, drag, and click' method; the users can also run their models and post-process the results in the same environment. Two thermodynamic property programs (GASP/WASP and GASPAK) provide required thermodynamic and thermophysical properties for 36 fluids: helium, methane, neon, nitrogen, carbon monoxide, oxygen, argon, carbon dioxide, fluorine, hydrogen, parahydrogen, water, kerosene (RP-1), isobutene, butane, deuterium, ethane, ethylene, hydrogen sulfide, krypton, propane, xenon, R-11, R-12, R-22, R-32, R-123, R-124, R-125, R-134A, R-152A, nitrogen trifluoride, ammonia, hydrogen peroxide, and air. The program also provides the options of using any incompressible fluid with constant density and viscosity or ideal gas. The users can also supply property tables for fluids that are not in the library. Twenty-four different resistance/source options are provided for modeling momentum sources or sinks in the branches. These options include pipe flow, flow through a restriction, noncircular duct, pipe flow with entrance and/or exit losses, thin sharp orifice, thick orifice, square edge reduction, square edge expansion, rotating annular duct, rotating radial duct
46 CFR 58.30-50 - Requirements for miscellaneous fluid power and control systems.
2010-10-01
...) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-50 Requirements for miscellaneous fluid power and control systems. (a) All fluid power and control... 46 Shipping 2 2010-10-01 2010-10-01 false Requirements for miscellaneous fluid power and control...
Numerical analysis of complex fluid-flow systems
Holland, R. L.
1980-01-01
Very flexible computer-assisted numerical analysis is used to solve dynamic fluid-flow equations characterizing computer-controlled heat dissipation system developed for Space lab. Losses caused by bends, ties, fittings, valves, and like are easily included, and analysis can solve both steady-state and transient cases. It can also interact with parallel thermal analysis.
System proportions fluid-flow in response to demand signals
1966-01-01
Control system provides proportioned fluid flow rates in response to demand signals. It compares a digital signal, representing a flow demand, with a reference signal to yield a control voltage to one or more solenoid valves connected to orifices of a predetermined size.
In vivo spatial frequency domain spectroscopy of two layer media
Yudovsky, Dmitry; Nguyen, John Quan M.; Durkin, Anthony J.
2012-10-01
Monitoring of tissue blood volume and local oxygen saturation can inform the assessment of tissue health, healing, and dysfunction. These quantities can be estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in skin can be confounded by the strong absorption of melanin in the epidermis and epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. Therefore, a method is desired that decouples the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. A previously developed inverse method based on a neural network forward model was applied to simulated spatial frequency domain reflectance of skin for multiple wavelengths in the near infrared. It is demonstrated that the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis can be determined independently and with minimal coupling. Then, the same inverse method was applied to reflectance measurements from a tissue simulating phantom and in vivo human skin. Oxygen saturation and total hemoglobin concentrations were estimated from the volar forearms of weakly and strongly pigmented subjects using a standard homogeneous model and the present two layer model.
Gurin, Péter; Varga, Szabolcs
2015-06-01
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
Gurin, Péter; Varga, Szabolcs
2015-06-14
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
Energy Technology Data Exchange (ETDEWEB)
Gurin, Péter; Varga, Szabolcs [Institute of Physics and Mechatronics, University of Pannonia, P.O. Box 158, Veszprém H-8201 (Hungary)
2015-06-14
We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore.
A Two-Layered Model for Dynamic Supply Chain Management Considering Transportation Constraint
Tanimizu, Yoshitaka; Harada, Kana; Ozawa, Chisato; Iwamura, Koji; Sugimura, Nobuhiro
This research proposes a two-layered model for dynamic supply chain management considering transportation constraint. The model provides a method for suppliers to estimate suitable prices and delivery times of products based on not only production schedules but also transportation plans in consideration of constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the model. The prototype system is available to determine suitable shipping times and loading capacities of transportation vehicles.
Retention Characteristics for Multiple-PhaseFluid Systems
Directory of Open Access Journals (Sweden)
Chia-Hsing Tsai and Gour-Tsyh Yeh
2012-01-01
Full Text Available The key objective of this paper is to point out that a widely used constitutive relationship between the degrees of saturation and capillary pressures for three-phasefluids over the past twenty five years has resulted in an undue constraint. To our knowledge, this constraint is neither physically justifiable nor is it theoretically supported. The discovery of the undue constraint leads this investigation to develop a viable parametric model to describe the constitutive relationship for a system of multiple fluids. Based on the physical consideration wherein fluid wettability follows a sequence, the proposed parametric model can be easily applied to any system of L arbitrary fluids. Three aspects are presented to confirm the plausibility and completeness of the model. First, the proposed closed-form expression of the saturation-capillary pressure head relationship is identical to van _ renowned model for two-phasefluid systems. Second, a constraint appearing in the widely used model is alleviated in the proposed model. Third, seven hypothetical examples are used to demonstrate that there is no need to impose the constraint on the sequence of capillary pressures. The results show the plausibility and completeness of the model for systems of multiple fluids. The proposed parametric model is a feasible analytic model which provides a generalized saturation-capillary pressure head relationship for any system with regard to multiple fluids. Hopefully, this study will pave a way for others to conduct experiments to validate the model further or develop other better non-constrained models based on experimental evidence.
Internal fluid mechanics research on supercomputers for aerospace propulsion systems
Miller, Brent A.; Anderson, Bernhard H.; Szuch, John R.
1988-01-01
The Internal Fluid Mechanics Division of the NASA Lewis Research Center is combining the key elements of computational fluid dynamics, aerothermodynamic experiments, and advanced computational technology to bring internal computational fluid mechanics (ICFM) to a state of practical application for aerospace propulsion systems. The strategies used to achieve this goal are to: (1) pursue an understanding of flow physics, surface heat transfer, and combustion via analysis and fundamental experiments, (2) incorporate improved understanding of these phenomena into verified 3-D CFD codes, and (3) utilize state-of-the-art computational technology to enhance experimental and CFD research. Presented is an overview of the ICFM program in high-speed propulsion, including work in inlets, turbomachinery, and chemical reacting flows. Ongoing efforts to integrate new computer technologies, such as parallel computing and artificial intelligence, into high-speed aeropropulsion research are described.
Computational Fluid and Particle Dynamics in the Human Respiratory System
Tu, Jiyuan; Ahmadi, Goodarz
2013-01-01
Traditional research methodologies in the human respiratory system have always been challenging due to their invasive nature. Recent advances in medical imaging and computational fluid dynamics (CFD) have accelerated this research. This book compiles and details recent advances in the modelling of the respiratory system for researchers, engineers, scientists, and health practitioners. It breaks down the complexities of this field and provides both students and scientists with an introduction and starting point to the physiology of the respiratory system, fluid dynamics and advanced CFD modeling tools. In addition to a brief introduction to the physics of the respiratory system and an overview of computational methods, the book contains best-practice guidelines for establishing high-quality computational models and simulations. Inspiration for new simulations can be gained through innovative case studies as well as hands-on practice using pre-made computational code. Last but not least, students and researcher...
Adaptation of systems to fluid changes; Adaptation des systemes aux changements de fluides
Energy Technology Data Exchange (ETDEWEB)
Clodic, D. [Ecole Nationale Superieure des Mines, 75 - Paris (France)
1996-12-31
Regulation constraints and the stoppage of CFCs production and HCFCs production in the future lead to rapid evolutions in the conceiving of refrigerating installations which are linked with refrigerant changes. The refrigerant/installation pair has become the aim of detailed analyses in order to understand the relation between the thermodynamical properties of fluids and the energy efficiency of refrigerating installations. The efficiency depends entirely on the global design of the installation while the choice of the fluid is only one element that contributes to this efficiency. This paper analyzes successively: the consequences of pure refrigerant substitution on volume and centrifugal compressors, and the constraints linked with the use of mixtures close to azeotropic compounds (R408A and R404A) and mixtures with temperature shift like R407C. In this last case, the replacement is deeply different in the case of water heat exchangers and in the case of air-circulation heat exchangers. (J.S.) 3 refs.
Designing Two-Layer Optical Networks with Statistical Multiplexing
Addis, B.; Capone, A.; Carello, G.; Malucelli, F.; Fumagalli, M.; Pedrin Elli, E.
The possibility of adding multi-protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question that arises is whether it is suitable to have MPLS nodes just at the edge of the network to collect packet traffic from users, or also to introduce MPLS facilities on a subset of the core nodes in order to exploit packet switching flexibility and multiplexing, thus providing induction of a better bandwidth allocation. In this article, we address this complex decisional problem with the support of a mathematical programming approach. We consider two-layer networks where MPLS is overlaid on top of transport networks-synchronous digital hierarchy (SDH) or wavelength division multiplexing (WDM)-depending on the required link speed. The discussions' decisions take into account the trade-off between the cost of adding MPLS support in the core nodes and the savings in the link bandwidth allocation due to the statistical multiplexing and the traffic grooming effects induced by MPLS nodes. The traffic matrix specifies for each point-to-point request a pair of values: a mean traffic value and an additional one. Using this traffic model, the effect of statistical multiplexing on a link allows the allocation of a capacity equal to the sum of all the mean values of the traffic demands routed on the link and only the highest additional one. The proposed approach is suitable to solve real instances in reasonable time.
Two-layer wireless distributed sensor/control network based on RF
Feng, Li; Lin, Yuchi; Zhou, Jingjing; Dong, Guimei; Xia, Guisuo
2006-11-01
A project of embedded Wireless Distributed Sensor/Control Network (WDSCN) based on RF is presented after analyzing the disadvantages of traditional measure and control system. Because of high-cost and complexity, such wireless techniques as Bluetooth and WiFi can't meet the needs of WDSCN. The two-layer WDSCN is designed based on RF technique, which operates in the ISM free frequency channel with low power and high transmission speed. Also the network is low cost, portable and moveable, integrated with the technologies of computer network, sensor, microprocessor and wireless communications. The two-layer network topology is selected in the system; a simple but efficient self-organization net protocol is designed to fit the periodic data collection, event-driven and store-and-forward. Furthermore, adaptive frequency hopping technique is adopted for anti-jamming apparently. The problems about power reduction and synchronization of data in wireless system are solved efficiently. Based on the discussion above, a measure and control network is set up to control such typical instruments and sensors as temperature sensor and signal converter, collect data, and monitor environmental parameters around. This system works well in different rooms. Experiment results show that the system provides an efficient solution to WDSCN through wireless links, with high efficiency, low power, high stability, flexibility and wide working range.
An annotation system for 3D fluid flow visualization
Loughlin, Maria M.; Hughes, John F.
1995-01-01
Annotation is a key activity of data analysis. However, current systems for data analysis focus almost exclusively on visualization. We propose a system which integrates annotations into a visualization system. Annotations are embedded in 3D data space, using the Post-it metaphor. This embedding allows contextual-based information storage and retrieval, and facilitates information sharing in collaborative environments. We provide a traditional database filter and a Magic Lens filter to create specialized views of the data. The system has been customized for fluid flow applications, with features which allow users to store parameters of visualization tools and sketch 3D volumes.
Institute of Scientific and Technical Information of China (English)
YANG; Ning(杨宁); CHEN; Zhining; (陈志宁); WANG; Yunyi; (王蕴仪); Chia; M.; Y.; W.
2003-01-01
This paper presents a novel two-layer electromagnetic bandgap (EBG) structure. The studies on the characteristics of the cell are carried out numerically and experimentally. A lumped-LC equivalent circuit extracted from the numerical simulation is used to model the bandgap characteristics of the proposed EBG structure. The influences of geometric parameters on the operation frequency and equivalent LC parameters are discussed. A meander line high performance bandstop filter and a notch type duplexer are designed and measured. These EBG structures are shown to have potential applications in microwave and RF systems.
SH-TM mathematical analogy for the two-layer case. A magnetotellurics application
Directory of Open Access Journals (Sweden)
J. Carcione
2017-02-01
Full Text Available The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised and TM (transverse-magnetic waves. In particular, we illustrate examples related to the magnetotelluric method applied to geothermal systems and consider the effects of anisotropy. The solution is tested with the classical solution for stratified isotropic media.
Crust-Mantle Structures and Gold Enrichment Mechanism of Mantle Fluid System
Institute of Scientific and Technical Information of China (English)
邓军; 孙忠实; 王庆飞; 韦延光
2003-01-01
Gold enrichment mechanism of ore-forming fluid is the essence of gold metallization.This paper summarizes the distinguishing symbols of mantle fluid and effect of crust-mantlestructure on fluid movement. Fluid moving processes include osmosis, surge, gas-liquid alterna-tion and mutation of fluid speed. During fluid movement, gold will be enriched gradually. Final-ly, a layered circulatory system is illustrated in this paper.
FINITE ELEMENT FOR STRESS-STRAIN STATE MODELING OF TWO-LAYERED AXIALLY SYMMETRIC SHELLS
Directory of Open Access Journals (Sweden)
K. S. Kurochka
2015-07-01
Full Text Available Subject of Research. Computation of composite material designs requires application of numerical methods. The finiteelement method usage is connected with surface approximation problems. Application of volumetric and laminar elements leads to systems with large sizes and a great amount of computation. The objective of this paper is to present an equivalent two-layer mathematical model for evaluation of displacements and stresses of cross-ply laminated cone shells subjected to uniformly distributed load. An axially symmetric element for shell problems is described. Method. Axially symmetric finite element is proposed to be applied in calculations with use of correlation for the inner work of each layer separately. It gives the possibility to take into account geometric and physical nonlinearities and non-uniformity in the layers of the shell. Discrete mathematical model is created on the base of the finite-element method with the use of possible motions principle and Kirchhoff–Love assumptions. Hermite element is chosen as a finite one. Cone shell deflection is considered as the quantity sought for. Main Results. One-layered and two-layered cone shells have been considered for proposed mathematical model verification with known analytical and numerical analytical solutions, respectively. The axial displacements of the two-layered cone are measured with an error not exceeding 5.4 % for the number of finite elements equal to 30. The proposed mathematical model requires fewer nodes to define the finite element meshing of the system and much less computation time. Thereby time for finding solution decreases considerably. Practical Relevance. Proposed model is applicable for computation of multilayered designs under axially symmetric loads: composite high-pressure bottles, cylinder shaped fiberglass pipes, reservoirs for explosives and flammable materials, oil and gas storage tanks.
High-viscosity fluid threads in weakly diffusive microfluidic systems
Cubaud, T.; Mason, T. G.
2009-07-01
We provide an overview of the flow dynamics of highly viscous miscible liquids in microfluidic geometries. We focus on the lubricated transport of high-viscosity fluids interacting with less viscous fluids, and we review methods for producing and manipulating single and multiple core-annular flows, i.e. viscous threads, in compact and plane microgeometries. In diverging slit microchannels, a thread's buckling instabilities can be employed for generating ordered and disordered miscible microstructures, as well as for partially blending low- and high-viscosity materials. The shear-induced destabilization of a thread that flows off-center in a square microchannel is examined as a means for continuously producing miscible dispersions. We show original compound threads and viscous dendrites that are generated using three fluids, each of which has a large viscosity contrast with the others. Thread motions in zones of microchannel extensions are examined in both miscible and immiscible environments. We demonstrate that high-viscosity fluid threads in weakly diffusive microfluidic systems correspond to the viscous primary flow and can be used as a starting point for studying and understanding the destabilizing effects of interfacial tension as well as diffusion. Characteristic of lubricated transport, threads facilitate the transport of very viscous materials in small fluidic passages, while mitigating dissipation. Threads are also potentially promising for soft material synthesis and diagnostics with independent control of the thread specific surface and residence time in micro-flow reactors.
Two-Layer Models for Landslide-Generated Tsunamis
Kirby, J. T., Jr.; Nicolsky, D.; Ma, G.; Shi, F.; Hsu, T. J.; Schnyder, J. S. D.
2014-12-01
We describe the development of a model for landslide tsunami generation based on a depth-integrated, fully deformable lower layer, and apply the resulting model to several laboratory and field cases. The approach follows on earlier studies where models for the slide layer and overlying water layer are formulated in the depth integrated, shallow water approximation, with kinematic and pressure coupling between the layers. In the present study, we use the 3D nonhydrostatic model of Ma et al (2012) to retain fully dispersive behavior in the upper fluid layer. In perfect fluid applications for shallow or intermediate depth waves, the model has been shown to predict tsunami response to solid slides (Enet and Grilli, 2007) with good accuracy using only three vertical sigma levels, making it computationally competitive with weakly dispersive Boussinesq formulations using a single depth-integrated layer. The effect of non-hydrostatic acceleration effects in the lower, depth integrated layer (resulting from steep substrate slopes) is implemented using the approach of Yamazaki et al (2009), who used a layer-averaged approximation for vertical acceleration to correct the hydrostatic pressure distribution. The two coupled models are formulated using a finite volume, TVD approach. Lateral boundaries of the slide volume may be arbitrarily approached relative to the initial still water shoreline, and thus the triggering event may be either submarine, subaerial, or a combination of the two. In our first implementation, we assume the lower layer to be a simple, viscous Newtonian fluid, following the approach of Jiang and LeBlond (1994) as corrected by Fine et al (1998). An alternate model is also constructed based on a rheology model representing a granular or debris flow supported by intergranular stresses, following Savage and Hutter (1989) and Iverson (1997). Both models amount to the addition of a single mass and horizontal momentum equation to the three-layer perfect fluid
Heat transfer and fluid flow in nuclear systems
Fenech, Henri
1982-01-01
Heat Transfer and Fluid in Flow Nuclear Systems discusses topics that bridge the gap between the fundamental principles and the designed practices. The book is comprised of six chapters that cover analysis of the predicting thermal-hydraulics performance of large nuclear reactors and associated heat-exchangers or steam generators of various nuclear systems. Chapter 1 tackles the general considerations on thermal design and performance requirements of nuclear reactor cores. The second chapter deals with pressurized subcooled light water systems, and the third chapter covers boiling water reacto
Institute of Scientific and Technical Information of China (English)
麦碧娴; 汪本善
1992-01-01
Presented in this paper are the rypes,salinities,homogenization temperatures and organic components of fluid inclusions formed at the four stages of diagenetic authigenesis in the Eogene of the Biyang Depression.The results of cooling experiments on fluid inclusions were used to determine the fluid system and composition of saline aqueous solution in each of the stages .The homogenization temperatures of saline aqueous solution inclusions and hydrocarbon organic inclu-sions have been corrected by two approaches ,and the trapping temperatures and pressures of fluid inclusions at each of the stages have been obtained.This strdy has shed light on the physicochemistry and evolution of diagenetic fluids.The diagentic fluid system is a system which was transformed from a chloride-bearing to a carbonate-bearing system along with the diagenic evolu-tion.The decrease of diagenetic temperature at Stage III of diagenetic authigenesis suggests that the depression would have experiences uplifting at that time.The fluorescent characteristics of fluid inclusions indicate the varieties of organic components in fluid inclusions both in time and in space.
Photoacoustic investigation of the effective diffusivity of two-layer semiconductors
Energy Technology Data Exchange (ETDEWEB)
Medina, J; Gurevich, Yu. G; Logvinov G, N; Rodriguez, P; Gonzalez de la Cruz, G. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)
2001-08-01
In this work, the problem of the effective thermal diffusivity of two-layer systems is investigated using the photoacoustic spectroscopy. The experimental results are examined in terms of the effective thermal parameters of the composite system determined from an homogeneous material which produces the same physical response under an external perturbation in the detector device. It is shown, that the effective thermal conductivity is not symmetric under exchange of the two layers of the composite; i.e., the effective thermal parameters depend upon which layer is illuminated in the photoacoustic experiments. Particular emphasis is given to the characterization of the interface thermal conductivity between the layer-system. [Spanish] En el presente trabajo se utiliza la espectroscopia fotoacustica para medir la difusividad termica de un sistema de dos capas. Los resultados experimentales son analizados en terminos de los parametros termicos efectivos determinados a partir de un material homogeneo, el cual produce la misma respuesta fisica bajo una perturbacion externa. Se puso particular enfasis en la caracterizacion de los efectos de interfase en el flujo de calor en el sistema de dos capas. Los resultados experimentales se comparan con el modelo teorico propuesto en este trabajo.
Analysis of Direct Samples of Early Solar System Aqueous Fluids
Zolensky, Michael E.; Bodnar, R J.; Fedele, L.; Yurimoto,H.; Itoh, S.; Fries, M.; Steele, A.
2012-01-01
Over the past three decades we have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. Some carbonaceous and ordinary chondrites have been altered by interactions with liquid water within the first 10 million years after formation of their parent asteroids. Millimeter to centimeter-sized aggregates of purple halite containing aqueous fluid inclusions were found in the matrix of two freshly-fallen brecciated H chondrite falls, Monahans (1998, hereafter simply "Monahans") (H5) and Zag (H3-6) (Zolensky et al., 1999; Whitby et al., 2000; Bogard et al., 2001) In order to understand origin and evolution of the aqueous fluids inside these inclusions we much measure the actual fluid composition, and also learn the O and H isotopic composition of the water. It has taken a decade for laboratory analytical techniques to catch up to these particular nanomole-sized aqueous samples. We have recently been successful in (1) measuring the isotopic composition of H and O in the water in a few fluid inclusions from the Zag and Monahans halite, (2) mineralogical characterization of the solid mineral phases associated with the aqueous fluids within the halite, and (3) the first minor element analyses of the fluid itself. A Cameca ims-1270 equipped with a cryo-sample-stage of Hokkaido University was specially prepared for the O and H isotopic measurements. The cryo-sample-stage (Techno. I. S. Corp.) was cooled down to c.a. -190 C using liquid nitrogen at which the aqueous fluid in inclusions was frozen. We excavated the salt crystal surfaces to expose the frozen fluids using a 15 keV Cs+ beam and measured negative secondary ions. The secondary ions from deep craters of approximately 10 m in depth emitted stably but the intensities changed gradually during measurement cycles because of shifting states of charge compensation, resulting in rather poor reproducibility of multiple measurements of standard fluid
Energy Technology Data Exchange (ETDEWEB)
Frisani, Angelo; Hassan, Yassin A; Ugaz, Victor M
2010-11-02
realizable k-epsilon model with two-layer all y+ wall treatment performs better than the other k-epsilon and k-omega turbulence models when compared to the experimental results and the Reynolds stress transport turbulence model results. A scaling analysis was developed to address the distortions introduced by the CFD model in simulating the physical phenomena inside the RCCS system with respect to the full plant configuration. The scaling analysis demonstrated that both the experimental facility and the CFD model achieve a satisfactory resemblance of the main flow characteristics inside the RCCS cavity region, and convection and radiation heat exchange phenomena are properly scaled from the actual plant.
Bcc crystal-fluid interfacial free energy in Yukawa systems.
Heinonen, V; Mijailović, A; Achim, C V; Ala-Nissila, T; Rozas, R E; Horbach, J; Löwen, H
2013-01-28
We determine the orientation-resolved interfacial free energy between a body-centered-cubic (bcc) crystal and the coexisting fluid for a many-particle system interacting via a Yukawa pair potential. For two different screening strengths, we compare results from molecular dynamics computer simulations, density functional theory, and a phase-field-crystal approach. Simulations predict an almost orientationally isotropic interfacial free energy of 0.12k(B)T/a(2) (with k(B)T denoting the thermal energy and a the mean interparticle spacing), which is independent of the screening strength. This value is in reasonable agreement with our Ramakrishnan-Yussouff density functional calculations, while a high-order fitted phase-field-crystal approach gives about 2-3 times higher interfacial free energies for the Yukawa system. Both field theory approaches also give a considerable anisotropy of the interfacial free energy. Our result implies that, in the Yukawa system, bcc crystal-fluid free energies are a factor of about 3 smaller than face-centered-cubic crystal-fluid free energies.
Structure of internal solitary waves in two-layer fluid at near-critical situation
Kurkina, O.; Singh, N.; Stepanyants, Y.
2015-05-01
A new model equation describing weakly nonlinear long internal waves at the interface between two thin layers of different density is derived for the specific relationships between the densities, layer thicknesses and surface tension between the layers. The equation derived and dubbed here the Gardner-Kawahara equation represents a natural generalisation of the well-known Korteweg-de Vries (KdV) equation containing the cubic nonlinear term as well as fifth-order dispersion term. Solitary wave solutions are investigated numerically and categorised in terms of two dimensionless parameters, the wave speed and fifth-order dispersion. The equation derived may be applicable to wave description in other media.
Two-layer networked learning control using self-learning fuzzy control algorithms
Institute of Scientific and Technical Information of China (English)
2007-01-01
Since the existing single-layer networked control systems have some inherent limitations and cannot effectively handle the problems associated with unreliable networks, a novel two-layer networked learning control system (NLCS) is proposed in this paper. Its lower layer has a number of local controllers that are operated independently, and its upper layer has a learning agent that communicates with the independent local controllers in the lower layer. To implement such a system, a packet-discard strategy is firstly developed to deal with network-induced delay and data packet loss. A cubic spline interpolator is then employed to compensate the lost data. Finally, the output of the learning agent based on a novel radial basis function neural network (RBFNN) is used to update the parameters of fuzzy controllers. A nonlinear heating, ventilation and air-conditioning (HVAC) system is used to demonstrate the feasibility and effectiveness of the proposed system.
21 CFR 882.5550 - Central nervous system fluid shunt and components.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components... Central nervous system fluid shunt and components. (a) Identification. A central nervous system fluid... central nervous system to an internal delivery site or an external receptacle for the purpose of relieving...
Computational Fluid Dynamics Analysis of an Evaporative Cooling System
Directory of Open Access Journals (Sweden)
Kapilan N.
2016-11-01
Full Text Available The use of chlorofluorocarbon based refrigerants in the air-conditioning system increases the global warming and causes the climate change. The climate change is expected to present a number of challenges for the built environment and an evaporative cooling system is one of the simplest and environmentally friendly cooling system. The evaporative cooling system is most widely used in summer and in rural and urban areas of India for human comfort. In evaporative cooling system, the addition of water into air reduces the temperature of the air as the energy needed to evaporate the water is taken from the air. Computational fluid dynamics is a numerical analysis and was used to analyse the evaporative cooling system. The CFD results are matches with the experimental results.
Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach
Camassa, R.; Falqui, G.; Ortenzi, G.
2017-02-01
The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite two-dimensional channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids’ inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, albeit in a non-trivial way. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, a family of approximate constants of the motion are explicitly constructed and used to find local solutions of the evolution equations by means of hodograph-like formulae.
Liquid Cooling System for CPU by Electroconjugate Fluid
Directory of Open Access Journals (Sweden)
Yasuo Sakurai
2014-06-01
Full Text Available The dissipated power of CPU for personal computer has been increased because the performance of personal computer becomes higher. Therefore, a liquid cooling system has been employed in some personal computers in order to improve their cooling performance. Electroconjugate fluid (ECF is one of the functional fluids. ECF has a remarkable property that a strong jet flow is generated between electrodes when a high voltage is applied to ECF through the electrodes. By using this strong jet flow, an ECF-pump with simple structure, no sliding portion, no noise, and no vibration seems to be able to be developed. And then, by the use of the ECF-pump, a new liquid cooling system by ECF seems to be realized. In this study, to realize this system, an ECF-pump is proposed and fabricated to investigate the basic characteristics of the ECF-pump experimentally. Next, by utilizing the ECF-pump, a model of a liquid cooling system by ECF is manufactured and some experiments are carried out to investigate the performance of this system. As a result, by using this system, the temperature of heat source of 50 W is kept at 60°C or less. In general, CPU is usually used at this temperature or less.
Transient thermohydraulic modeling of two-phase fluid systems
Blet, N.; Delalandre, N.; Ayel, V.; Bertin, Y.; Romestant, C.; Platel, V.
2012-11-01
This paper presents a transient thermohydraulic modeling, initially developed for a capillary pumped loop in gravitational applications, but also possibly suitable for all kinds of two-phase fluid systems. Using finite volumes method, it is based on Navier-Stokes equations for transcribing fluid mechanical aspects. The main feature of this 1D-model is based on a network representation by analogy with electrical. This paper also proposes a parametric study of a counterflow condenser following the sensitivity to inlet mass flow rate and cold source temperature. The comparison between modeling results and experimental data highlights a good numerical evaluation of temperatures. Furthermore, the model is able to represent a pretty good dynamic evolution of hydraulic variables.
An intelligent data acquisition system for fluid mechanics research
Cantwell, E. R.; Zilliac, G.; Fukunishi, Y.
1989-01-01
This paper describes a novel data acquisition system for use with wind-tunnel probe-based measurements, which incorporates a degree of specific fluid dynamics knowledge into a simple expert system-like control program. The concept was developed with a rudimentary expert system coupled to a probe positioning mechanism operating in a small-scale research wind tunnel. The software consisted of two basic elements, a general-purpose data acquisition system and the rulebased control element to take and analyze data and supplying decisions as to where to measure, how many data points to take, and when to stop. The system was validated in an experiment involving a vortical flow field, showing that it was possible to increase the resolution of the experiment or, alternatively, reduce the total number of data points required, to achieve parity with the results of most conventional data acquisition approaches.
21 CFR 862.1455 - Lecithin/sphingomyelin ratio in amniotic fluid test system.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lecithin/sphingomyelin ratio in amniotic fluid... Clinical Chemistry Test Systems § 862.1455 Lecithin/sphingomyelin ratio in amniotic fluid test system. (a) Identification. A lecithin/sphingomyelin ratio in amniotic fluid test system is a device intended to measure the...
Spin-3/2 Ising model AFM/AFM two-layer lattice with crystal field
Institute of Scientific and Technical Information of China (English)
Erhan Albayrak; Ali Yigit
2009-01-01
The spin-3/2 Ising model is investigated for the case of antiferromagnetic (AFM/AFM) interactions on the two-layer Bethe lattice by using the exact recursion relations in the pairwise approach for given coordination numbers q = 3, 4 and 6 when the layers are under the influences of equal external magnetic and equal crystal fields. The ground state, (GS) phase diagrams are obtained on the different planes in detail and then the temperature-dependent phase diagrams of the system are calculated accordingly. It is observed that the system presents both second- and first-order phase transitions for all q, therefore, tricritical points. It is also found that the system exhibits double-critical end points and isolated points. The model aiso presents two Néel temperatures, T_N, and the existence of which leads to the reentrant behaviour.
Risks of an epidemic in a two-layered railway-local area traveling network
Ruan, Zhongyuan; Hui, Pakming; Lin, Haiqing; Liu, Zonghua
2013-01-01
In view of the huge investments into the construction of high speed rails systems in USA, Japan, and China, we present a two-layer traveling network model to study the risks that the railway network poses in case of an epidemic outbreak. The model consists of two layers with one layer representing the railway network and the other representing the local-area transportation subnetworks. To reveal the underlying mechanism, we also study a simplified model that focuses on how a major railway affects an epidemic. We assume that the individuals, when they travel, take on the shortest path to the destination and become non-travelers upon arrival. When an infection process co-evolves with the traveling dynamics, the railway serves to gather a crowd, transmit the disease, and spread infected agents to local area subnetworks. The railway leads to a faster initial increase in infected agents and a higher steady state infection, and thus poses risks; and frequent traveling leads to a more severe infection. These features revealed in simulations are in agreement with analytic results of a simplified version of the model.
Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations
Directory of Open Access Journals (Sweden)
E. Ramdan
2009-01-01
Full Text Available Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode. The aim of this study is to measure and calculate the earth resistance of a combined grid-multiple rods electrode buried in a two-layer soil and to confirm the simplicity and accuracy of the used formula. Approach: Soil resistivity was measured using Wenner four point method. Advanced earth resistivity measurement interpretation techniques which include graphical curve matching based on master curves and an advanced computer program based on a genetic algorithm are used in this study. Results: Based on the resistivity data, the earth resistance value was calculated using the formulas obtained from the literature. Measurements of the earth resistance of the earthing system were also conducted using the fall of potential method. Conclusion/Recommendations: A very good agreement was obtained between the measured and calculated earth resistance values. This research is the first time ever conducted where the measured earth resistance values are compared directly with the calculated earth values.
Smart Fluid Systems: The Advent of Autonomous Liquid Robotics.
Chiolerio, A; Quadrelli, Marco B
2017-07-01
Organic, inorganic or hybrid devices in the liquid state, kept in a fixed volume by surface tension or by a confining membrane that protects them from a harsh environment, could be used as biologically inspired autonomous robotic systems with unique capabilities. They could change shape according to a specific exogenous command or by means of a fully integrated adaptive system, and provide an innovative solution for many future applications, such as space exploration in extreme or otherwise challenging environments, post-disaster search and rescue in ground applications, compliant wearable devices, and even in the medical field for in vivo applications. This perspective provides an initial assessment of existing capabilities that could be leveraged to pursue the topic of "Smart Fluid Systems" or "Liquid Engineered Systems".
Cerebrospinal fluid scintigraphy in traumas to the nervous system
Energy Technology Data Exchange (ETDEWEB)
Nikolov, P. (Meditsinska Akademiya, Sofia (Bulgaria). Nauchen Inst. po Rentgenologiya i Radiobiologiya)
1983-01-01
The results of cerebrospinal fluid scintigraphy in 48 patients who had undergone trauma to the nervous system were studied. This method has gained rather insufficient acceptance in the diagnosis of this disease, in fact, it was helpful in detecting a high percentage of pathologic changes (80 per cent). Their type and localization structure was as follows: Narrowing of the spinal CSF space in 25 patients and 1 suspective; encephalonasal fistula - 3 patients; blockade of the lateral pathway of the CSF to the brain convexity - 4 patients; pathologic CSF circulation; dilatation of the convex brain cysterns with disturbances at the resorption site - 3 patients; combined spino-encephalic lesion - 1 patient.
The peak effect (PE) region of the antiferromagnetic two layer Ising nanographene
Energy Technology Data Exchange (ETDEWEB)
Şarlı, Numan, E-mail: numansarli82@gmail.com [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Akbudak, Salih [Department of Physics, Adiyaman University, 02100 Adiyaman (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, 06800 Ankara (Turkey); Ellialtıoğlu, Mehmet Recai [Department of Physics Engineering, Hacettepe University, 06800 Ankara (Turkey)
2014-11-01
In this work, the magnetic properties of the ferromagnetic and antiferromagnetic two layer spin-1/2 Ising nanographene systems are investigated within the effective field theory. We find that the magnetizations and the hysteresis behaviors of the central graphene atoms are similar to those of the edge graphene atoms in the ferromagnetic case. But, they are quite different in the antiferromagnetic case. The antiferromagnetic central graphene atoms exhibit type II superconductivity and they have triple hysteresis loop. The peak effect (PE) region is observed on the hysteresis curves of the antiferromagnetic Ising nanographene system. Therefore, we suggest that there is a strong relationship between the antiferromagnetism and the peak effect. Our results are in agreement with some experimental works in recent literature.
TWO-LAYER SECURE PREVENTION MECHANISM FOR REDUCING E-COMMERCE SECURITY RISKS
Directory of Open Access Journals (Sweden)
Sen-Tarng Lai
2015-12-01
Full Text Available E-commerce is an important information system in the network and digital age. However, the network intrusion, malicious users, virus attack and system security vulnerabilities have continued to threaten the operation of the e-commerce, making e-commerce security encounter serious test. How to improve ecommerce security has become a topic worthy of further exploration. Combining routine security test and security event detection procedures, this paper proposes the Two-Layer Secure Prevention Mechanism (TLSPM. Applying TLSPM, routine security test procedure can identify security vulnerability and defect, and develop repair operations. Security event detection procedure can timely detect security event, and assist follow repair. TLSPM can enhance the e-commerce security and effectively reduce the security risk of e-commerce critical data and asset.
A Two-Layer Mathematical Modelling of Drug Delivery to Biological Tissues
Chakravarty, Koyel
2016-01-01
Local drug delivery has received much recognition in recent years, yet it is still unpredictable how drug efficacy depends on physicochemical properties and delivery kinetics. The purpose of the current study is to provide a useful mathematical model for drug release from a drug delivery device and consecutive drug transport in biological tissue, thereby aiding the development of new therapeutic drug by a systemic approach. In order to study the complete process, a two-layer spatio-temporal model depicting drug transport between the coupled media is presented. Drug release is described by considering solubilisation dynamics of drug particle, diffusion of the solubilised drug through porous matrix and also some other processes like reversible dissociation / recrystallization, drug particle-receptor binding and internalization phenomena. The model has led to a system of partial differential equations describing the important properties of drug kinetics. This model contributes towards the perception of the roles...
Some considerations on numerical schemes for treating hyperbolicity issues in two-layer models
Sarno, L.; Carravetta, A.; Martino, R.; Papa, M. N.; Tai, Y.-C.
2017-02-01
Multi-layer depth-averaged models are widely employed in various hydraulic engineering applications. Yet, such models are not strictly hyperbolic. Their equation systems typically lose hyperbolicity when the relative velocities between layers become too large, which is associated with Kelvin-Helmholtz instabilities involving turbulent momentum exchanges between the layers. Focusing on the two-layer case, we present a numerical improvement that locally avoids the loss of hyperbolicity. The proposed modification introduces an additional momentum exchange between layers, whose value is iteratively calculated to be strictly sufficient to keep the system hyperbolic. The approach can be easily implemented in any finite volume scheme and there is no limitation concerning the density ratio between layers. Numerical examples, employing both HLL-type and Roe-type approximate Riemann solvers, are reported to validate the method and its key features.
Computational transport phenomena of fluid-particle systems
Arastoopour, Hamid; Abbasi, Emad
2017-01-01
This book concerns the most up-to-date advances in computational transport phenomena (CTP), an emerging tool for the design of gas-solid processes such as fluidized bed systems. The authors examine recent work in kinetic theory and CTP and illustrate gas-solid processes’ many applications in the energy, chemical, pharmaceutical, and food industries. They also discuss the kinetic theory approach in developing constitutive equations for gas-solid flow systems and how it has advanced over the last decade as well as the possibility of obtaining innovative designs for multiphase reactors, such as those needed to capture CO2 from flue gases. Suitable as a concise reference and a textbook supplement for graduate courses, Computational Transport Phenomena of Gas-Solid Systems is ideal for practitioners in industries involved with the design and operation of processes based on fluid/particle mixtures, such as the energy, chemicals, pharmaceuticals, and food processing. Explains how to couple the population balance e...
Systems Improved Numerical Differencing Analyzer And Fluid Integrator (SINDA '85/FLUINT)
Goble, Richard; Cullimore, Brent; Ring, Steven; Jensen, Carl
1993-01-01
Comprehensive thermal analysis system handles complex models such as evaporators and permits interaction of thermal and fluid problems. Design flexibility provided by 20,000 nodes, 100,000 conductors, 100 thermal submodels, and 10 fluid submodels.
Computational fluid dynamics (CFD) studies of a miniaturized dissolution system.
Frenning, G; Ahnfelt, E; Sjögren, E; Lennernäs, H
2017-02-08
Dissolution testing is an important tool that has applications ranging from fundamental studies of drug-release mechanisms to quality control of the final product. The rate of release of the drug from the delivery system is known to be affected by hydrodynamics. In this study we used computational fluid dynamics to simulate and investigate the hydrodynamics in a novel miniaturized dissolution method for parenteral formulations. The dissolution method is based on a rotating disc system and uses a rotating sample reservoir which is separated from the remaining dissolution medium by a nylon screen. Sample reservoirs of two sizes were investigated (SR6 and SR8) and the hydrodynamic studies were performed at rotation rates of 100, 200 and 400rpm. The overall fluid flow was similar for all investigated cases, with a lateral upward spiraling motion and central downward motion in the form of a vortex to and through the screen. The simulations indicated that the exchange of dissolution medium between the sample reservoir and the remaining release medium was rapid for typical screens, for which almost complete mixing would be expected to occur within less than one minute at 400rpm. The local hydrodynamic conditions in the sample reservoirs depended on their size; SR8 appeared to be relatively more affected than SR6 by the resistance to liquid flow resulting from the screen.
A Scintillator Purification Plant and Fluid Handling System for SNO+
Ford, Richard J
2015-01-01
A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with 130Te. The plant includes processes multi-stage dual-stream distillation, column water extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator with PPO and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. The construction and commissioning status is updated.
Anisotropic pressure molecular dynamics for atomic fluid systems
Energy Technology Data Exchange (ETDEWEB)
Romero-Bastida, M [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Avenida Universidad 1001, Chamilpa, Cuernavaca, Morelos 62209 (Mexico); Lopez-Rendon, R [Departamento de QuImica, Universidad Autonoma Metropolitana-Iztapalapa, Av San Rafael Atlixco 186, 09340 Mexico DF (Mexico)
2007-07-20
The MTK equations (Martyna G J, Tobias D J and Klein M L 1994 J. Chem. Phys. 101 4177-89), which simulate the constant-pressure, constant-temperature NPT ensemble, have been modified to simulate an anisotropic pressure along a single coordinate axis, thus rendering the NP{sub zz}T ensemble. The necessary theory of non-Hamiltonian systems is briefly reviewed in order to analytically prove that the proposed equations indeed sample the desired ensemble. A previously derived geometric integrator for the MTK equations is modified to take into account the anisotropic pressure and volume fluctuations. We choose a Lennard-Jones fluid as an illustrative example. The density distribution function, as well as various thermodynamic and interfacial properties of the model system in a liquid-vapour coexistence state, was computed to test the robustness of the proposed equations of motion to simulate the NP{sub zz}T ensemble.
High Performance Hybrid Two Layer Router Architecture for FPGAs Using Network On Chip
Ezhumalai, P; Arun, C; Sakthivel, P; Sridharan, D
2010-01-01
Networks on Chip is a recent solution paradigm adopted to increase the performance of Multicore designs. The key idea is to interconnect various computation modules (IP cores) in a network fashion and transport packets simultaneously across them, thereby gaining performance. In addition to improving performance by having multiple packets in flight, NoCs also present a host of other advantages including scalability, power efficiency, and component reuse through modular design. This work focuses on design and development of high performance communication architectures for FPGAs using NoCs Once completely developed, the above methodology could be used to augment the current FPGA design flow for implementing multicore SoC applications. We design and implement an NoC framework for FPGAs, MultiClock OnChip Network for Reconfigurable Systems (MoCReS). We propose a novel microarchitecture for a hybrid two layer router that supports both packetswitched communications, across its local and directional ports, as well as...
Fluid Flow Prediction with Development System Interwell Connectivity Influence
Bolshakov, M.; Deeva, T.; Pustovskikh, A.
2016-03-01
In this paper interwell connectivity has been studied. First of all, literature review of existing methods was made which is divided into three groups: Statistically-Based Methods, Material (fluid) Propagation-Based Methods and Potential (pressure) Change Propagation-Based Method. The disadvantages of the first and second groups are as follows: methods do not involve fluid flow through porous media, ignore any changes of well conditions (BHP, skin factor, etc.). The last group considers changes of well conditions and fluid flow through porous media. In this work Capacitance method (CM) has been chosen for research. This method is based on material balance and uses weight coefficients lambdas to assess well influence. In the next step synthetic model was created for examining CM. This model consists of an injection well and a production well. CM gave good results, it means that flow rates which were calculated by analytical method (CM) show matching with flow rate in model. Further new synthetic model was created which includes six production and one injection wells. This model represents seven-spot pattern. To obtain lambdas weight coefficients, the delta function was entered using by minimization algorithm. Also synthetic model which has three injectors and thirteen producer wells was created. This model simulates seven-spot pattern production system. Finally Capacitance method (CM) has been adjusted on real data of oil Field Ω. In this case CM does not give enough satisfying results in terms of field data liquid rate. In conclusion, recommendations to simplify CM calculations were given. Field Ω is assumed to have one injection and one production wells. In this case, satisfying results for production rates and cumulative production were obtained.
Karelsky, K V; Slavin, A G
2011-01-01
The numerical method for study of hydrodynamic flows over an arbitrary bed profile in the presence of external force is proposed in this paper. This method takes into account the external force effect, it uses the quasi-two-layer model of hydrodynamic flows over a stepwise boundary with consideration of features of the flow near the step. A distinctive feature of the proposed method is the consideration of the properties of the process of the waterfall, namely the fluid flow on the step in which the fluid does not wet part of the vertical wall of the step. The presence of dry zones in the vertical part of the step indicates violation of the conditions of hydrostatic flow. The quasi-two-layer approach allows to determine the size of the dry zone of the vertical component of the step. Consequently it gives an opportunity to figure out the amount of kinetic energy dissipation. There are performed the numerical simulations based on the proposed algorithm of various physical phenomena, such as a breakdown of the r...
Fluid-magmatic systems and volcanic centers in Northern Caucasus
Sobisevich, Alexey L.; Masurenkov, Yuri P.; Pouzich, Irina N.; Laverova, Ninel I.
2013-04-01
The central segment of Alpine mobile folded system and the Greater Caucasus is considered with respect to fluid-magmatic activity within modern and Holocene volcanic centers. A volcanic center is a combination of volcanoes, intrusions, and hydrothermal features supported by endogenous flow of matter and energy localised in space and steady in time; responsible for magma generation and characterized by structural representation in the form of circular dome and caldera associations. Results of complimentary geological and geophysical studies carried out in the Elbrus volcanic area and the Pyatogorsk volcanic center are presented. The deep magmatic source and the peripheral magmatic chamber of the Elbrus volcano are outlined via comparative analysis of geological and experimental geophysical data (microgravity studies, magneto-telluric profiling, temperature of carbonaceous mineral waters). It has been determined that the peripheral magmatic chamber and the deep magmatic source of the volcano are located at depths of 0-7 and 20-30 km below sea level, respectively, and the geothermal gradient beneath the volcano is 100°C/km. In this study, analysis of processes of modern heat outflux produced by carbonaceous springs in the Elbrus volcanic center is carried out with respect to updated information about spatial configuration of deep fluid-magmatic structures of the Elbrus volcano. It has been shown, that degradation of the Elbrus glaciers throughout the historical time is related both to climatic variations and endogenic heat. The stable fast rate of melting for the glaciers on the volcano's eastern slope is of theoretical and practical interest as factors of eruption prognosis. The system approach to studying volcanism implies that events that seem to be outside the studied process should not be ignored. This concerns glaciers located in the vicinity of volcanoes. The crustal rocks contacting with the volcanism products exchange matter and energy between each other
Computational fluid dynamics applications to improve crop production systems
Computational fluid dynamics (CFD), numerical analysis and simulation tools of fluid flow processes have emerged from the development stage and become nowadays a robust design tool. It is widely used to study various transport phenomena which involve fluid flow, heat and mass transfer, providing det...
Therapeutic Options for Controlling Fluids in the Visual System
Curry, Kristina M.; Wotring, Virginia E.
2014-01-01
Visual Impairment/Intracranial Pressure (VIIP) is a newly recognized risk at NASA. The VIIP project examines the effect of long-term exposure to microgravity on vision of crewmembers before and after they return to Earth. Diamox (acetazolamide) is a medication which is used to decrease intraocular pressure; however, it carries a 3% risk of kidney stones. Astronauts are at a higher risk of kidney stones during spaceflight and the use Diamox would only increase the risk; therefore alternative therapies were investigated. Histamine 2 (H2) antagonist acid blockers such as cimetidine, ranitidine, famotidine and nizatidine are typically used to relieve the symptoms of gastroesophageal reflux disease (GERD). H2 receptors have been found in the human visual system, which has led to research on the use of H2 antagonist blockers to control fluid production in the human eye. Another potential therapeutic strategy is targeted at aquaporins, which are water channels that help maintain fluid homeostasis. Aquaporin antagonists are also known to affect intracranial pressure which can in turn alter intraocular pressure. Studies on aquaporin antagonists suggest high potential for effective treatment. The primary objective of this investigation is to review existing research on alternate medications or therapy to significantly reduce intracranial and intraocular pressure. A literature review was conducted. Even though we do not have all the answers quite yet, a considerable amount of information was discovered, and findings were narrowed, which should allow for more conclusive answers to be found in the near future.
Fully automated dialysis system based on the central dialysis fluid delivery system.
Kawanishi, Hideki; Moriishi, Misaki; Sato, Takashi; Taoka, Masahiro
2009-01-01
The fully automated dialysis system (FADS) was developed as an improvement over previous patient monitors used in the treatment of hemodialysis, with the aim of standardizing and promoting labor-saving in such treatment. This system uses backfiltration dialysis fluid to perform priming, blood rinse back and rapid fluid replenishment, and causes guiding of blood into the dialyzer by the drainage pump for ultrafiltration. This requires that the dialysis fluid used be purified to a high level. The central dialysis fluid delivery system (CDDS) combines the process of the creation and supply of dialysis water and dialysis fluid to achieve a level of purity equivalent with ultrapure dialysis fluid. FADS has the further advantages of greater efficiency and streamlined operation, reducing human error and the risk of infection without requiring the storage or disposal of normal saline solution. The simplification of hemodialysis allows for greater frequency of dialysis or extended dialysis, enabling treatment to be provided in line with the patient's particular situation. FADS thus markedly improves the reliability, safety and standardization of dialysis procedures while ensuring labor-saving in these procedures, making it of particular utility for institutions dealing with dialysis on a large scale.
Reflected light intensity profile of two-layer tissues: phantom experiments.
Ankri, Rinat; Taitelbaum, Haim; Fixler, Dror
2011-08-01
Experimental measurements of the reflected light intensity from two-layer phantoms are presented. We report, for the first time, an experimental observation of a typical reflected light intensity behavior for the two-layer structure characterized by two different slopes in the reflected light profile of the irradiated tissue. The point in which the first slope changes to the second slope, named as the crossover point, depends on the upper layer thickness as well as on the ratio between the absorption coefficients of the two layers. Since similar experiments from one-layer phantoms present a monotonic decay behavior, the existence and the location of the crossover point can be used as a diagnostic fingerprint for two-layer tissue structures. This pertains to two layers with greater absorptivity in the upper layer, which is the typical biological case in tissues like skin.
Ultraefficient reduced model for countercurrent two-layer flows
Lavalle, Gianluca; Vila, Jean-Paul; Lucquiaud, Mathieu; Valluri, Prashant
2017-01-01
We investigate the dynamics of two superposed layers with density contrast flowing countercurrent inside a channel, when the lower layer is much thinner than the wavelength of interfacial waves. We apply a low-dimensional film model to the bottom (heavier) layer and introduce a fast and efficient method to predict the onset of flow reversal in this phase. We study three vertical scenarios with different applied pressure gradients and compare the temporal growth rates of linear and weakly nonlinear waves to the Orr-Sommerfeld problem and to the weakly nonlinear theory, respectively. At the loading point, i.e., when a large wave hump stands at the interface, our spatiotemporal analysis shows that the system is absolutely unstable. We then present profiles of nonlinear saturated waves, pressure field, and streamline distribution in agreement with direct numerical simulation. The reduced model presented here allows us to explore the effect of the upper-layer speed on the wave pattern, showing that the wave profile is very sensitive when the mean film thickness, rather than the liquid flow rate, is maintained constant in the simulation. In addition, we show the strong effect of surface tension on both the maximum wave hump and the crest steepness before the loading point. Finally, we reveal how the nonlinear wave speed affects the vortex distribution within the lower layer by analyzing the stream function under different scenarios.
Optical density measurements in a multiphase cryogenic fluid flow system
Korman, Valentin; Wiley, John; Gregory, Don A.
2006-05-01
An accurate determination of fluid flow in a cryogenic propulsion environment is difficult under the best of circumstances. The extreme thermal environment increases the mechanical constraints, and variable density conditions create havoc with traditional flow measurement schemes. Presented here are secondary results of cryogenic testing of an all-optical sensor capable of a mass flow measurement by directly interrogating the fluid's density state and a determination of the fluid's velocity. The sensor's measurement basis does not rely on any inherent assumptions as to the state of the fluid flow (density or otherwise). The fluid sensing interaction model will be discussed. Current test and evaluation data and future development work will be presented.
Energy Technology Data Exchange (ETDEWEB)
Schiele, O.; Florjanicic, D.
1979-04-03
A nuclear steam supply system wherein each of a plurality of centrifugal pumps begins to operate with full cavitation in response to an abrupt drop of system pressure in the event of leakage is described. This is achieved by influencing a net positive suction head of each pump over the entire range of fluid flow and/or by influencing the net positive suction head upstream of the pumps. The first mode of causing the pumps to operate with full cavitation includes an appropriate selection of the inlet angle and/or inlet diameter of the pump impeller, the provision of auxiliary stationary guide wheels which are located upstream of the pumps and can circulate the fluid in or counter to the direction of rotation of the respecive pump impellers, or the provision of suitably curved guide vanes in the pumps. The second mode includes interrupting the admission of undercooled fluid into the system upstream of the pumps.
COTHERM: Modelling fluid-rock interactions in Icelandic geothermal systems
Thien, Bruno; Kosakowski, Georg; Kulik, Dmitrii
2014-05-01
Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced geothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. We model the mineralogical and porosity evolution of Icelandic geothermal systems with 1D and 2D reactive transport models. These geothermal systems are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. The shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. We investigate two contrasting geothermal systems: Krafla, for which the water recharge consists of meteoritic water; and Reykjanes, for which the water recharge mainly consists of seawater. The initial rock composition is a fresh basalt. We use the GEM-Selektor geochemical modeling package [1] for calculation of kinetically controlled mineral equilibria between the rock and the ingression water. We consider basalt minerals dissolution kinetics according to Palandri & Kharaka [2]. Reactive surface areas are assumed to be geometric surface areas, and are corrected using a spherical-particle surface/mass relationship. For secondary minerals, we consider the partial equilibrium assuming that the primary mineral dissolution is slow, and the secondary mineral precipitation is fast. Comparison of our modeling results with the mineralogical assemblages observed in the
Quantification of the specific yield in a two-layer hard-rock aquifer model
Durand, Véronique; Léonardi, Véronique; de Marsily, Ghislain; Lachassagne, Patrick
2017-08-01
Hard rock aquifers (HRA) have long been considered to be two-layer systems, with a mostly capacitive layer just below the surface, the saprolite layer, and a mainly transmissive layer underneath, the fractured layer. Although this hydrogeological conceptual model is widely accepted today within the scientific community, it is difficult to quantify the respective storage properties of each layer with an equivalent porous medium model. Based on an HRA field site, this paper attempts to quantify in a distinct manner the respective values of the specific yield (Sy) in the saprolite and the fractured layer, with the help of a deterministic hydrogeological model. The study site is the Plancoët migmatitic aquifer located in north-western Brittany, France, with piezometric data from 36 observation wells surveyed every two weeks for eight years. Whereas most of the piezometers (26) are located where the water table lies within the saprolite, thus representing the specific yield of the unconfined layer (Sy1), 10 of them are representative of the unconfined fractured layer (Sy2), due to their position where the saprolite is eroded or unsaturated. The two-layer model, based on field observations of the layer geometry, runs with the MODFLOW code. 81 values of the Sy1/Sy2 parameter sets were tested manually, as an inverse calibration was not able to calibrate these parameters. In order to calibrate the storage properties, a new quality-of-fit criterion called ;AdVar; was also developed, equal to the mean squared deviation of the seasonal piezometric amplitude variation. Contrary to the variance, AdVar is able to select the best values for the specific yield in each layer. It is demonstrated that the saprolite layer is about 2.5 times more capacitive than the fractured layer, with Sy1 = 10% (7% < Sy1 < 15%) against Sy2 = 2% (1% < Sy2 < 3%), in this particular example.
Characterization of Fluid Flow in Paper-Based Microfluidic Systems
Walji, Noosheen; MacDonald, Brendan
2014-11-01
Paper-based microfluidic devices have been presented as a viable low-cost alternative with the versatility to accommodate many applications in disease diagnosis and environmental monitoring. Current microfluidic designs focus on the use of silicone and PDMS structures, and several models have been developed to describe these systems; however, the design process for paper-based devices is hindered by a lack of prediction capability. In this work we simplify the complex underlying physics of the capillary-driven flow mechanism in a porous medium and generate a practical numerical model capable of predicting the flow behaviour. We present our key insights regarding the properties that dictate the behaviour of fluid wicking in paper-based microfluidic devices. We compare the results from our model to experiments and discuss the application of our model to design of paper-based microfluidic devices for arsenic detection in drinking water in Bangladesh.
Safety System for Controlling Fluid Flow into a Suction Line
England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Cronise, Raymond J. (Inventor)
2015-01-01
A safety system includes a sleeve fitted within a pool's suction line at the inlet thereof. An open end of the sleeve is approximately aligned with the suction line's inlet. The sleeve terminates with a plate that resides within the suction line. The plate has holes formed therethrough. A housing defining a plurality of distinct channels is fitted in the sleeve so that the distinct channels lie within the sleeve. Each of the distinct channels has a first opening on one end thereof and a second opening on another end thereof. The second openings reside in the sleeve. Each of the distinct channels is at least approximately three feet in length. The first openings are in fluid communication with the water in the pool, and are distributed around a periphery of an area of the housing that prevents coverage of all the first openings when a human interacts therewith.
EXPERIMENTAL BUBBLE FORMATION IN A LARGE SCALE SYSTEM FOR NEWTONIAN AND NONNEWTONIAN FLUIDS
Energy Technology Data Exchange (ETDEWEB)
Leishear, R; Michael Restivo, M
2008-06-26
The complexities of bubble formation in liquids increase as the system size increases, and a photographic study is presented here to provide some insight into the dynamics of bubble formation for large systems. Air was injected at the bottom of a 28 feet tall by 30 inch diameter column. Different fluids were subjected to different air flow rates at different fluid depths. The fluids were water and non-Newtonian, Bingham plastic fluids, which have yield stresses requiring an applied force to initiate movement, or shearing, of the fluid. Tests showed that bubble formation was significantly different in the two types of fluids. In water, a field of bubbles was formed, which consisted of numerous, distributed, 1/4 to 3/8 inch diameter bubbles. In the Bingham fluid, large bubbles of 6 to 12 inches in diameter were formed, which depended on the air flow rate. This paper provides comprehensive photographic results related to bubble formation in these fluids.
Computational fluid dynamics for turbomachinery internal air systems.
Chew, John W; Hills, Nicholas J
2007-10-15
Considerable progress in development and application of computational fluid dynamics (CFD) for aeroengine internal flow systems has been made in recent years. CFD is regularly used in industry for assessment of air systems, and the performance of CFD for basic axisymmetric rotor/rotor and stator/rotor disc cavities with radial throughflow is largely understood and documented. Incorporation of three-dimensional geometrical features and calculation of unsteady flows are becoming commonplace. Automation of CFD, coupling with thermal models of the solid components, and extension of CFD models to include both air system and main gas path flows are current areas of development. CFD is also being used as a research tool to investigate a number of flow phenomena that are not yet fully understood. These include buoyancy-affected flows in rotating cavities, rim seal flows and mixed air/oil flows. Large eddy simulation has shown considerable promise for the buoyancy-driven flows and its use for air system flows is expected to expand in the future.
Self-gravitating fluid systems and galactic dark matter
Banik, Uddipan; Bhattacharya, Kaushik; Sarkar, Tapobrata
2016-01-01
In this work we model galaxy-like structures as self-gravitating fluids, and analyse their properties in the Newtonian framework. For isotropic fluids, we show that this leads to a generalised Hernquist profile that admits flat rotation curves at large radial distances. For two-fluid component models, we show analytically that physicality of the solutions demand that one of the fluids is necessarily exotic, i.e has negative pressure, excepting for the case where the density profile is that of the isothermal sphere. We reconcile this result with a corresponding relativistic analysis. Our work can be applied to cases where the gravitating fluids are interpreted as dark fluids, whose microscopic constituents are dark matter particles, which may accompany or cause gravitational collapse giving birth to galaxy like structures. We elaborate on such collapse processes, which might lead to naked singularities.
System and method for determining velocity of electrically conductive fluid
Polzin, Kurt A. (Inventor); Korman, Valentin (Inventor); Markusic, Thomas E. (Inventor); Stanojev, Boris Johann (Inventor)
2008-01-01
A flowing electrically-conductive fluid is controlled between an upstream and downstream location thereof to insure that a convection timescale of the flowing fluid is less than a thermal diffusion timescale of the flowing fluid. First and second nodes of a current-carrying circuit are coupled to the fluid at the upstream location. A current pulse is applied to the current-carrying circuit so that the current pulse travels through the flowing fluid to thereby generate a thermal feature therein at the upstream location. The thermal feature is convected to the downstream location where it is monitored to detect a peak associated with the thermal feature so-convected. The velocity of the fluid flow is determined using a time-of-flight analysis.
Cerebrospinal fluid cytology studies of neuropsychiatric systemic lupus erythematosus
Directory of Open Access Journals (Sweden)
CHEN Lin
2013-02-01
Full Text Available Background Neuropsychiatric systemic lupus erythematosus (NP-SLE is the central nervous system (CNS involvement of systemic lupus erythematosus (SLE. The diagnosis of NP-SLE may be difficult due to the lack of specific biomarker. CNS cerebrospinal fluid (CSF cytology is diagnostic significant to CNS autoimmune disease. This paper described the characteristics of CSF cytology and evaluated its diagnostic value in NP-SLE. Methods Seventy-six eligible patients with clear diagnosis of NP-SLE were collected for CSF cytological examinations. Results The CSF cytology findings of 25 cases in 76 were abnormal, among which 16 cases showed lymphocytic inflammatory reactions; 8 cases had slight increase of neutrophile granulocyte percent; 9 cases showed lymphocyte-neutrophile inflammation. Activated lymphocytes together with monocytes were present in 24 cases. Among those cases, abnormal endocytosis of monocytes, which presented as monocytes phagocytosing lymphocytes or plasmocytes, was shown in 17 cases; plasmocytes were found in 17 cases. Conclusion The diagnosis of NP-SLE is based on clinical, neuroimaging and CSF studies. Among these methods, the CSF cytology findings are quite useful in practice, since the CSF cytological inflammatory reactions, especially the presentation of abnormal phagocytes in CSF is typical in NP-SLE and indicates its vasculitic mechanism.
The search for and analysis of direct samples of early Solar System aqueous fluids.
Zolensky, Michael E; Bodnar, Robert J; Yurimoto, Hisayoshi; Itoh, Shoichi; Fries, Marc; Steele, Andrew; Chan, Queenie H-S; Tsuchiyama, Akira; Kebukawa, Yoko; Ito, Motoo
2017-05-28
We describe the current state of the search for direct, surviving samples of early, inner Solar System fluids-fluid inclusions in meteorites. Meteoritic aqueous fluid inclusions are not rare, but they are very tiny and their characterization is at the state of the art for most analytical techniques. Meteoritic fluid inclusions offer us a unique opportunity to study early Solar System brines in the laboratory. Inclusion-by-inclusion analyses of the trapped fluids in carefully selected samples will, in the immediate future, provide us detailed information on the evolution of fluids as they interacted with anhydrous solid materials. Thus, real data can replace calculated fluid compositions in thermochemical calculations of the evolution of water and aqueous reactions in comets, asteroids, moons and the terrestrial planets.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'. © 2017 The Author(s).
de Graaf, Inge E. M.; van Beek, Rens L. P. H.; Gleeson, Tom; Moosdorf, Nils; Schmitz, Oliver; Sutanudjaja, Edwin H.; Bierkens, Marc F. P.
2017-04-01
Groundwater is the world's largest accessible source of freshwater to satisfy human water needs. Moreover, groundwater buffers variable precipitation rates over time, thereby effectively sustaining river flows in times of droughts and evaporation in areas with shallow water tables. In this study, building on previous work, we simulate groundwater head fluctuations and groundwater storage changes in both confined and unconfined aquifer systems using a global-scale high-resolution (5‧) groundwater model by deriving new estimates of the distribution and thickness of confining layers. Inclusion of confined aquifer systems (estimated 6-20% of the total aquifer area) improves estimates of timing and amplitude of groundwater head fluctuations and changes groundwater flow paths and groundwater-surface water interaction rates. Groundwater flow paths within confining layers are shorter than paths in the underlying aquifer, while flows within the confined aquifer can get disconnected from the local drainage system due to the low conductivity of the confining layer. Lateral groundwater flows between basins are significant in the model, especially for areas with (partially) confined aquifers were long flow paths crossing catchment boundaries are simulated, thereby supporting water budgets of neighboring catchments or aquifer systems. The developed two-layer transient groundwater model is used to identify hot-spots of groundwater depletion. Global groundwater depletion is estimated as 7013 km3 (137 km3y-1) over 1960-2010, which is consistent with estimates of previous studies.
14 CFR 23.1099 - Carburetor deicing fluid system detail design.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor deicing fluid system detail design. 23.1099 Section 23.1099 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Powerplant Induction System § 23.1099 Carburetor deicing fluid system detail design. Each carburetor...
Linking rigid multibody systems via controllable thin fluid films
DEFF Research Database (Denmark)
Estupinan, Edgar Alberto; Santos, Ilmar
2009-01-01
, this paper gives a theoretical contribution to the combined fields of fluid–structure interaction and vibration control. The methodology is applied to a reciprocating linear compressor, where the dynamics of the mechanical components are described with help of multibody dynamics. The crank is linked...... of the journal orbits, maximum fluid film pressure and minimum fluid film thickness....
Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations
National Research Council Canada - National Science Library
E. Ramdan; N. M. Nor; K. Ramar
2009-01-01
Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode...
Review of progress in understanding the fluid geochemistry of the Cerro Prieto Geothermal System
Energy Technology Data Exchange (ETDEWEB)
Truesdell, A.H.; Nehring, N.L.; Thompson, J.M.; Janik, C.J.; Coplen, T.B.
1982-08-10
Fluid geochemistry has played a major role in the authors present understanding of the Cerro Prieto geothermal system. Fluid chemical and isotopic compositions have been used to indicate the origin of water, salts, and gases, original subsurface temperature and fluid flow, fluid-production mechanims, and production-induced aquifer boiling and cold-water entry. The extensive geochemical data and interpretation for Cerro Prieto published from 1964 to 1981 are reviewed and discussed. Fluid geochemistry must continue to play an important role in the further development of the Cerro Prieto field.
A review of progress in understanding the fluid geochemistry of the Cerro Prieto geothermal system
Truesdell, A.H.; Nehring, N.L.; Thompson, J.M.; Janik, C.J.; Coplen, T.B.
1984-01-01
Fluid geochemistry has played a major role in our present understanding of the Cerro Prieto geothermal system. Fluid chemical and isotopic compositions have been used to indicate the origin of water, salts and gases, original subsurface temperature and fluid flow, fluid-production mechanisms, and production-induced aquifer boiling and cold-water entry. The extensive geochemical data and interpretations for Cerro Prieto published from 1964 to 1981 are reviewed and discussed. Fluid geochemistry must continue to play an important role in the further development of the Cerro Prieto field. ?? 1984.
Inferring topologies via driving-based generalized synchronization of two-layer networks
Wang, Yingfei; Wu, Xiaoqun; Feng, Hui; Lu, Jun-an; Xu, Yuhua
2016-05-01
The interaction topology among the constituents of a complex network plays a crucial role in the network’s evolutionary mechanisms and functional behaviors. However, some network topologies are usually unknown or uncertain. Meanwhile, coupling delays are ubiquitous in various man-made and natural networks. Hence, it is necessary to gain knowledge of the whole or partial topology of a complex dynamical network by taking into consideration communication delay. In this paper, topology identification of complex dynamical networks is investigated via generalized synchronization of a two-layer network. Particularly, based on the LaSalle-type invariance principle of stochastic differential delay equations, an adaptive control technique is proposed by constructing an auxiliary layer and designing proper control input and updating laws so that the unknown topology can be recovered upon successful generalized synchronization. Numerical simulations are provided to illustrate the effectiveness of the proposed method. The technique provides a certain theoretical basis for topology inference of complex networks. In particular, when the considered network is composed of systems with high-dimension or complicated dynamics, a simpler response layer can be constructed, which is conducive to circuit design. Moreover, it is practical to take into consideration perturbations caused by control input. Finally, the method is applicable to infer topology of a subnetwork embedded within a complex system and locate hidden sources. We hope the results can provide basic insight into further research endeavors on understanding practical and economical topology inference of networks.
Extreme events statistics in a two-layer quasi-geostrophic atmospheric model
Galfi, Vera Melinda; Bodai, Tamas; Lucarini, Valerio
2016-04-01
Extreme events statistics provides a theoretical framework to analyze and predict extreme events based on the convergence of the distribution of the extremes to some limiting distribution. In this work we analyze the convergence of the distribution of extreme events to the Generalized Extreme Value (GEV) distribution and to the Generalized Pareto Distribution (GPD), using a two-layer quasi-geostrophic atmospheric model, and compare our results with theoretical findings from the field of extreme value theory for dynamical systems. We study the behavior of the GEV shape parameter by increasing the block size and of the GPD shape parameter by increasing the threshold, and compare the inferred parameters with a theoretical shape parameter that depends only on the geometrical properties of the attractor. The main objective is to find out whether this theoretical shape parameter can be used to evaluate extreme event analysis based on model output. For this, we perform very long simulations. We run our system with two different levels of forcing determined by two different meridional temperature gradients, one inducing a medium level of chaos and the other one a high level of chaos. We analyze in both cases extremes of energy variables.
A new converter for improving efficiency of multi-actuators fluid power system
Energy Technology Data Exchange (ETDEWEB)
Xue, Yong; Shang, JianZhong; Yang, JunHong; Wang Zhuo [National University of Defense Technology, Changsha (China)
2016-05-15
This paper is concerned with the application of energy efficient fluid power in mobile robots system and proposes a new fluid power converter system which is analogous to a boost converter in power electronics. The fluid power converter system is based on the principle of pulse-width modulation. The fluid power converter has an effect akin to an electrical switched inductance transformer, wherein the output pressure or flow rate can be stepped up or down. Using an inductive reactance device (an inertia mass-block), the output flow and pressure can be varied to meet the load by a means that does not rely on dissipation of power (the resistance control). The simulation model based on the mathematics models of the components is built to analyse the performance of the fluid power converter. It is clearly shown that the fluid power converter has higher energy efficiency than conventional resistance control manners.
Institute of Scientific and Technical Information of China (English)
杨之乐; 王秉臣; 费敏锐; 姚奇; 侯维岩
2011-01-01
为应对工业无线测控需要而提出的单跳令牌环网受无线模块通信距离限制,无法满足实际工业应用需求.为了延长通信距离,扩大令牌环网应用范围,提出一种在基于原令牌环协议的基础上挂接主从的两层无线监控网络WICN - TL( Wireless Industrial Control Network -Two Layers),介绍了其协议模型的拓扑结构及通信流程,将该协议在基于IEEE802.15.4a的硬件平台NanoNET 上加以实现,并接入PROFIBUS - DP现场总线系统,在某污水处理厂进行了实地测试.测试结果表明,该协议具有良好的通信能力和较大的覆盖范围,能够适应工业环境的应用需要.
Rotating pulse valve for downhole fluid telemetry systems
Energy Technology Data Exchange (ETDEWEB)
Duckworth, A.
1993-06-01
An apparatus for generating pressure pulses in a drilling fluid in a drill collar section of a drill string is described comprising: rotating valve means substantially diametrically mounted in a drill string segment, said rotating valve means alternating between a first position corresponding to more resistance to the flow of drilling fluid and a second position corresponding to less resistance to the flow of drilling fluid, said rotating valve means being impelled by the flow of drilling fluid; and restraining means disposed in the drill collar segment, said restraining means restraining said rotating valve means in said first position and releasing said rotating valve means from said first position in response to control signals indicative of a downhole condition.
System for concentrating and analyzing particles suspended in a fluid
Fiechtner, Gregory J [Bethesda, MD; Cummings, Eric B [Livermore, CA; Singh, Anup K [Danville, CA
2011-04-26
Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.
Contamination Control and Monitoring of Tap Water as Fluid in Industrial Tap Water Hydraulic Systems
DEFF Research Database (Denmark)
Conrad, Finn; Adelstorp, Anders
1998-01-01
Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems.......Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems....
21 CFR 866.5860 - Total spinal fluid immuno-logical test system.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Total spinal fluid immuno-logical test system. 866.5860 Section 866.5860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN....5860 Total spinal fluid immuno-logical test system. (a) Identification. A total spinal...
1969-01-01
Levels of contamination in fluid systems can be determined by a definition of a particle by a mathematical model, a method for calculating the tolerance limits of contamination, and an estimation of the probability that the contamination on the surface will migrate with the fluid in the system.
Contamination Control and Monitoring of Tap Water as Fluid in Industrial Tap Water Hydraulic Systems
DEFF Research Database (Denmark)
Conrad, Finn; Adelstorp, Anders
1998-01-01
Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems.......Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems....
Theoretical aspects concerning working fluids in hydraulic systems
Directory of Open Access Journals (Sweden)
Tița Irina
2017-01-01
Full Text Available Among the properties of working fluid, viscosity is the most important as it regards especially to pumps. In order to study the behavior of hydrostatic transmission it is important to create a reliable research instrument for dynamic simulation. Our research expertise being in SimHydraulics consequently this instrument is the suitable block diagram. The purpose of this paper is to present the possible ways to customize the properties of the working fluid in the block diagram.
Sullivan, Scott C; Fansler, Douglas
2014-10-14
A vehicle having multiple isolated fluid circuits configured to be filled through a common fill port includes a first fluid circuit disposed within the vehicle, the first fluid circuit having a first fill port, a second fluid circuit disposed within the vehicle, and a conduit defining a fluid passageway between the first fluid circuit and second fluid circuit, the conduit including a valve. The valve is configured such that the first and second fluid circuits are fluidly coupled via the passageway when the valve is open, and are fluidly isolated when the valve is closed.
Finite element analysis of fluid-structure interaction in pipeline systems
Energy Technology Data Exchange (ETDEWEB)
Sreejith, B.; Jayaraj, K.; Ganesan, N.; Padmanabhan, C. E-mail: ouli@iitm.ac.in; Chellapandi, P.; Selvaraj, P
2004-02-01
Pipes used for transporting high velocity pressurized fluids often pe rate under time-varying conditions due to pump and valve operations. This an cause vibration problems. In the present work, a finite element formulation for the fully coupled dynamic equations of motion to include the effect of fluid-structure interaction (FSI) is introduced and applied to a pipe line system used in nuclear reactors. The fluid finite element model is based on flow velocity as the variable. The response of fluid filled pipe lines to valve closure excitation has been studied. The model is validated with an experimental pipeline system.
Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence
Farhat, Aseel; Titi, Edriss S; Ziane, Mohammed
2012-01-01
We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integra...
Two-Layer Linear MPC Approach Aimed at Walking Beam Billets Reheating Furnace Optimization
Directory of Open Access Journals (Sweden)
Silvia Maria Zanoli
2017-01-01
Full Text Available In this paper, the problem of the control and optimization of a walking beam billets reheating furnace located in an Italian steel plant is analyzed. An ad hoc Advanced Process Control framework has been developed, based on a two-layer linear Model Predictive Control architecture. This control block optimizes the steady and transient states of the considered process. Two main problems have been addressed. First, in order to manage all process conditions, a tailored module defines the process variables set to be included in the control problem. In particular, a unified approach for the selection on the control inputs to be used for control objectives related to the process outputs is guaranteed. The impact of the proposed method on the controller formulation is also detailed. Second, an innovative mathematical approach for stoichiometric ratios constraints handling has been proposed, together with their introduction in the controller optimization problems. The designed control system has been installed on a real plant, replacing operators’ mental model in the conduction of local PID controllers. After two years from the first startup, a strong energy efficiency improvement has been observed.
Convergence of Extreme Value Statistics in a Two-Layer Quasi-Geostrophic Atmospheric Model
Directory of Open Access Journals (Sweden)
Vera Melinda Gálfi
2017-01-01
Full Text Available We search for the signature of universal properties of extreme events, theoretically predicted for Axiom A flows, in a chaotic and high-dimensional dynamical system. We study the convergence of GEV (Generalized Extreme Value and GP (Generalized Pareto shape parameter estimates to the theoretical value, which is expressed in terms of the partial information dimensions of the attractor. We consider a two-layer quasi-geostrophic atmospheric model of the mid-latitudes, adopt two levels of forcing, and analyse the extremes of different types of physical observables (local energy, zonally averaged energy, and globally averaged energy. We find good agreement in the shape parameter estimates with the theory only in the case of more intense forcing, corresponding to a strong chaotic behaviour, for some observables (the local energy at every latitude. Due to the limited (though very large data size and to the presence of serial correlations, it is difficult to obtain robust statistics of extremes in the case of the other observables. In the case of weak forcing, which leads to weaker chaotic conditions with regime behaviour, we find, unsurprisingly, worse agreement with the theory developed for Axiom A flows.
Critical properties of XY model on two-layer Villain-ferromagnetic lattice
Institute of Scientific and Technical Information of China (English)
Wang Yi; R. Quartu; Liu Xiao-Yan; Han Ru-Qi; Horiguchi Tsuyoshi
2004-01-01
We investigate phase transitions of the XY model on a two-layer square lattice which consists of a Villain plane(J) and a ferromagnetic plane (I), using Monte Carlo simulations and a histogram method. Depending on the values of interaction parameters (I, J), the system presents three phases: namely, a Kosterlitz-Thouless (KT) phase in which the two planes are critical for I predominant over J, a chiral phase in which the two planes have a chiral order for J predominant over I and a new phase in which only the Villain plane has a chiral order and the ferromagnetic plane is paramagnetic with a small value of chirality. We clarify the nature of phase transitions by using a finite size scaling method. We find three different kinds of transitions according to the values of (I, J): the KT transition, the Ising transition and an XY-Ising transition with v = 0.849(3). It turns out that the Ising or XY-Ising transition is associated with the disappearance of the chiral order in the Villain plane.
Ogawa, Tomonari; Matsuda, Akihiko; Yamaguchi, Yumiko; Sasaki, Yusuke; Kanayama, Yuki; Maeda, Tadaaki; Noiri, Chie; Hasegawa, Hajime; Matsumura, Osamu; Mitarai, Tetsuya
2012-01-01
Most dialysis clinics in Japan have mainly adopted the central dialysis fluid delivery system (CDDS) to provide constant treatment to many patients. Chemical disinfection is the major maintenance method of the CDDS. Our clinic introduced an automated hot water disinfection system that used the heat conduction effect to disinfect a reverse osmosis (RO) device and dialysis fluid supply equipment. Endotoxin level and the amount of viable bacteria often showed abnormal values before introduction of this system. After its introduction, weekly disinfection resulted in endotoxin levels and the amount of viable bacteria lower than measurement sensitivity. In hot water disinfection, water heated to 90°C in the RO tank flows into the dialysis fluid supply equipment. The maximum temperature inside the tank of the supply equipment is 86.3°C. (We confirmed that the temperature was maintained at 80°C or more for 10 minutes or more during the monitoring.) Dialysate purification was maintained even after introduction of the automated hot water disinfection system and the dialysate could be supplied stably by the CDDS. Therefore, this disinfection system might be very useful in terms of both cost and safety, and can be used for dialysis treatment of multiple patients.
Cerebrospinal fluid interleukin-6 in central nervous system inflammatory diseases.
Directory of Open Access Journals (Sweden)
Alexandre Wullschleger
Full Text Available BACKGROUND: Interleukin (IL-6 is recognised as an important cytokine involved in inflammatory diseases of the central nervous system (CNS. OBJECTIVE: To perform a large retrospective study designed to test cerebrospinal fluid (CSF IL-6 levels in the context of neurological diseases, and evaluate its usefulness as a biomarker to help discriminate multiple sclerosis (MS from other inflammatory neurological diseases (OIND. PATIENTS AND METHODS: We analyzed 374 CSF samples for IL-6 using a quantitative enzyme-linked immunosorbent assay. Groups tested were composed of demyelinating diseases of the CNS (DD, n = 117, including relapsing-remitting MS (RRMS, n = 65, primary progressive MS (PPMS, n = 11, clinically isolated syndrome (CIS, n = 11, optic neuritis (ON, n = 30; idiopathic transverse myelitis (ITM, n = 10; other inflammatory neurological diseases (OIND, n = 35; and non-inflammatory neurological diseases (NIND, n = 212. Differences between groups were analysed using Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: CSF IL-6 levels exceeded the positivity cut-off of 10 pg/ml in 18 (51.4% of the 35 OIND samples, but in only three (3.9% of the 76 MS samples collected. CSF IL-6 was negative for all NIND samples tested (0/212. IL-6 cut-off of 10 pg/ml offers 96% sensitivity to exclude MS. CONCLUSION: CSF IL-6 may help to differentiate MS from its major differential diagnosis group, OIND.
Investigation and Optimisation of a Discrete Fluid Power PTO-system for Wave Energy Converters
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard
recently focused research on improving the power take off (PTO) system converting the mechanical motion of the floats into electricity. This has brought attention to discrete fluid power (DFP) technology, especially secondary controlled common pressure rail systems. A novel discrete PTO-system has been...... proposed and found feasible for the Wavestar WEC. However, with a technology shift from a continuous to a discrete fluid power PTO-system, new challenges emerge. The current project investigates and optimises the novel discrete fluid power PTO-system proposed for the Wavestar WEC. Initiating from...... an investigation of energy extraction by WECs utilising a discrete PTO force, an investigation of the system configuration is conducted. Hence, the configuration of the multi-chamber cylinder and the common pressure rails are investigated for the discrete fluid power force system. A method for choosing the system...
Single Neuron PID Control of Aircraft Deicing Fluids Rapid Heating System
2013-01-01
Aircraft deicing fluids rapid heating system is widely used in aircraft ground deicing to ensure that the operation of flights can be safe and efficient. Aiming at the temperature turbulence problem of aircraft deicing system, this paper presents the single neuron PID control strategy which combine the advantage of conventional PID control with artificial neuron control. The aircraft deicing fluids rapid heating system and the scheme and working principle of the system is introduced. Simulati...
Multi-fluid renewable geo-energy systems and methods
Energy Technology Data Exchange (ETDEWEB)
Buscheck, Thomas A.
2017-08-22
A geo-energy production method for extracting thermal energy from a reservoir formation. A production well extracts brine from the reservoir formation. A plurality of working fluid injection ("WFI") wells may be arranged proximate to the production well to at least partially circumscribe the production well. A plurality of brine production ("BP") wells may be arranged in a vicinity of the WFI wells to at least partially circumscribe the WFI wells. A working fluid is injected into the WFI wells to help drive a flow of the brine up through the production and BP wells, together with at least a portion of the injected working fluid. Parasitic-load time-shifting and to storing of excess solar thermal energy may also be performed.
Process analysis of two-layered tube hydroforming with analytical and experimental verification
Energy Technology Data Exchange (ETDEWEB)
Seyedkashi, S. M. Hossein [The University of Birjand, Birjand (Iran, Islamic Republic of); Panahizadeh R, Valiollah [Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Xu, Haibin; Kim, Sang Yun; Moon, Young Hoon [Pusan National University, Busan (Korea, Republic of)
2013-01-15
Two-layered tubular joints are suitable for special applications. Designing and manufacturing of two layered components require enough knowledge about the tube material behavior during the hydroforming process. In this paper, hydroforming of two-layered tubes is investigated analytically, and the results are verified experimentally. The aim of this study is to derive an analytical model which can be used in the process design. Fundamental equations are written for both of the outer and inner tubes, and the total forming pressure is obtained from these equations. Hydroforming experiments are carried out on two different combinations of materials for inner and outer tubes; case 1: copper/aluminum and case 2: carbon steel/stainless steel. It is observed that experimental results are in good agreement with the theoretical model obtained for estimation of forming pressure able to avoid wrinkling.
Wetzel, Alfredo N; Cerovecki, Ivana; Hendershott, Myrl C; Karsten, Richard H; Miller, Peter D
2013-01-01
In this study the influence of stratification on surface tidal elevations in a two-layer analytical model is examined. The model assumes linearized, non-rotating, shallow-water dynamics in one dimension with astronomical forcing and allows for arbitrary topography. Both large scale (barotropic) and small scale (baroclinic) components of the surface tidal elevation are shown to be affected by stratification. It is also shown that the topography and basin boundaries affect the sensitivity of the barotropic surface tide to stratification significantly. In a companion paper it is shown that the barotropic tide in two-layer numerical models run in realistic global domains differs from its value in one-layer numerical models by amounts qualitatively consistent with analytic predictions from this paper. The analytical model also roughly predicts the sensitivity to perturbations in stratification in the two-layer domain model. Taken together, this paper and the companion paper therefore provide a framework to underst...
Ultrasound evaluation of the cesarean scar: comparison between one- and two layer uterotomy closure
DEFF Research Database (Denmark)
Glavind, Julie; Madsen, Lene Duch; Uldbjerg, Niels
Objectives: To compare the residual myometrial thickness and the size of the cesarean scar defect after one- and two layer uterotomy closure. Methods: From July 2010 a continuous two-layer uterotomy closure technique replaced a continuous one-layer technique after cesarean delivery...... at the Department of Obstetrics and Gynecology at Aarhus University Hospital. A total of 149 consecutively invited women (68 women with one-layer and 81 women with two-layer closure) had their cesarean scar examined with 2D transvaginal sonography (TVS) 6-16 months post partum. Inclusion criteria were non......-pregnant women with one previous elective cesarean, no post-partum uterine infection or uterine re-operation, and no type 1 diabetes. Scar defect width, depth, and residual myometrial thickness were measured on the sagittal plane, and scar defect length was measured on the transverse plane. Results: The median...
Large eddy simulation on thermal fluid mixing in a T-junction piping system
Energy Technology Data Exchange (ETDEWEB)
Selvam, P. Karthick; Kulenovic, R.; Laurien, E. [Stuttgart Univ. (Germany). Inst fuer Kernenergie und Energiesysteme (IKE)
2014-11-15
High cycle thermal fatigue damage caused in piping systems is an important problem encountered in the context of nuclear safety and lifetime management of a Nuclear Power Plant (NPP). The T-junction piping system present in the Residual Heat Removal System (RHRS) is more vulnerable to thermal fatigue cracking. In this numerical study, thermal mixing of fluids at temperature difference (?T) of 117 K between the mixing fluids is analyzed. Large Eddy Simulation (LES) is performed with conjugate heat transfer between the fluid and structure. LES is performed based on the Fluid-Structure Interaction (FSI) test facility at University of Stuttgart. The results show an intense turbulent mixing of fluids downstream of T-junction. Amplitude of temperature fluctuations near the wall region and its corresponding frequency distribution is analyzed. LES is performed using commercial CFD software ANSYS CFX 14.0.
The Generalized Energy Equation and Instability in the Two-layer Barotropic Vortex
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The linear two-layer barotropic primitive equations in cylindrical coordinates are used to derive a generalized energy equation, which is subsequently applied to explain the instability of the spiral wave in the model. In the two-layer model, there are not only the generalized barotropic instability and the super highspeed instability, but also some other new instabilities, which fall into the range of the Kelvin-Helmholtz instability and the generalized baroclinic instability, when the upper and lower basic flows are different.They are perhaps the mechanisms of the generation of spiral cloud bands in tropical cyclones as well.
Systems and methods for thermal imaging technique for measuring mixing of fluids
Energy Technology Data Exchange (ETDEWEB)
Booten, Charles; Tomerlin, Jeff; Winkler, Jon
2016-06-14
Systems and methods for thermal imaging for measuring mixing of fluids are provided. In one embodiment, a method for measuring mixing of gaseous fluids using thermal imaging comprises: positioning a thermal test medium parallel to a direction gaseous fluid flow from an outlet vent of a momentum source, wherein when the source is operating, the fluid flows across a surface of the medium; obtaining an ambient temperature value from a baseline thermal image of the surface; obtaining at least one operational thermal image of the surface when the fluid is flowing from the outlet vent across the surface, wherein the fluid has a temperature different than the ambient temperature; and calculating at least one temperature-difference fraction associated with at least a first position on the surface based on a difference between temperature measurements obtained from the at least one operational thermal image and the ambient temperature value.
Floquet-Bloch waves and suppression of vibrations in multi-scale fluid-solid systems
Carta, Giorgio; Movchan, Alexander B
2016-01-01
The paper presents a mathematical model for an industry inspired problem of vibration isolation applied to a cluster of elastic fluid-filled containers. We develop a systematic approach employing full fluid-solid interaction and Floquet-Bloch waves in periodic multi-scale systems. The analytical findings are accompanied by numerical simulations, including frequency response analyses and computations in the transient regime.
Single crystal growth and anisotropic crystal-fluid interface tension in soft colloidal systems
Nguyen, V.D.; Hu, Z.; Schall, P.
2011-01-01
We measure the anisotropy of the crystal-fluid interfacial free energy in soft colloidal systems. A temperature gradient is used to direct crystal nucleation and control the growth of large single crystals in order to achieve well-equilibrated crystal-fluid interfaces. Confocal microscopy is used to
Directory of Open Access Journals (Sweden)
U. Marschner
2014-09-01
Full Text Available Two-layer flexure beams often serve as basic transducers in actuators and sensors. In this paper a generalized description of their stimuli-influenced mechanical behavior is derived. For small deflection angles this description includes a multi-port circuit or network representation with lumped elements for a beam part of finite length. A number of coupled finite beam parts model the dynamic behavior including the first natural frequencies of the beam. For piezoelectric and piezomagnetic interactions, reversible transducer models are developed. The piezomagnetic two-layer beam model is extended to include solenoid and planar coils. Linear network theory is applied in order to determine network parameters and to simplify the circuit representation. The resulting circuit model is the basis for a fast simulation of the dynamic system behavior with advanced circuit simulators and, thus, the optimization of the system. It is also a useful tool for understanding and explaining this multi-domain system through basic principles of general system theory.
Preheating of fluid in a supercritical Brayton cycle power generation system at cold startup
Wright, Steven A.; Fuller, Robert L.
2016-07-12
Various technologies pertaining to causing fluid in a supercritical Brayton cycle power generation system to flow in a desired direction at cold startup of the system are described herein. A sensor is positioned at an inlet of a turbine, wherein the sensor is configured to output sensed temperatures of fluid at the inlet of the turbine. If the sensed temperature surpasses a predefined threshold, at least one operating parameter of the power generation system is altered.
Solar-heat transport fluids for solar energy collection systems (a collection of quarterly reports)
Energy Technology Data Exchange (ETDEWEB)
1978-01-01
This document consists of several quarterly reports that cover the progress made by the Houston Chemical Company, who is developing noncorrosive fluid subsystem(s) compatible with closed-loop solar heating and combined heating and hot water systems. The system is also to be compatible with both metallic and non-metallic plumbing systems, and any combination of these. At least 100 gallons of each type of fluid recommended by the contractor will be delivered, and a number of fluids will be performance tested.
Novel procedure to compute a contact zone magnitude of vibrations of two-layered uncoupled plates
Directory of Open Access Journals (Sweden)
Awrejcewicz J.
2005-01-01
Full Text Available A novel iteration procedure for dynamical problems, where in each time step, a contacting plates' zone is improved, is proposed. Therefore, a zone and magnitude of a contact load are also improved. Investigations of boundary conditions' influence on externally driven vibrations of uncoupled two-layer plates, where for each of the layers, the Kirchhoff hypothesis holds, are carried out.
Learning behavior and temporary minima of two-layer neural networks
Annema, Anne J.; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans
1994-01-01
This paper presents a mathematical analysis of the occurrence of temporary minima during training of a single-output, two-layer neural network, with learning according to the back-propagation algorithm. A new vector decomposition method is introduced, which simplifies the mathematical analysis of
Franken, Michel; Stramigioli, Stefano; Misra, Sarthak; Secchi, Cristian; Macchelli, Alessandro
2011-01-01
In this paper, a two-layer approach is presented to guarantee the stable behavior of bilateral telemanipulation sys- tems in the presence of time-varying destabilizing factors such as hard contacts, relaxed user grasps, stiff control settings, and/or communication delays. The approach splits the con
Coupling of Flexural and Longitudinal Damped Vibration in a Two-Layered Beam
Directory of Open Access Journals (Sweden)
F. Pourroy
1998-01-01
Full Text Available In dynamics, the effect of varying the constitutive materials’ thickness of a two-layered beam is investigated. Resonance frequencies and damping variations are determined. It is shown that for specific thicknesses the coupling of longitudinal and flexural vibrations influences the global modal damping ratio significantly.
Two-layer sheet of gelatin: A new topical hemostatic agent.
Takagi, Toshitaka; Tsujimoto, Hiroyuki; Torii, Hiroko; Ozamoto, Yuki; Hagiwara, Akeo
2016-11-02
Uncontrolled surgical bleeding is associated with increased morbidity, mortality, and hospital cost. Topical hemostatic agents available today have problems controlling hemostatic effects; furthermore, their handling is difficult and they are unsafe. We devised a new hemostatic agent comprising gelatin sponge and film designed to be applied to the bleeding site, thereby creating a topical hemostatic agent made of gelatin alone. The gelatin was prepared by alkali treatment to eliminate viral activity. Hemostatic effects, surgical handling, and tissue reactions of the materials, namely a two-layer sheet of gelatin, TachoSil, and gelatin sponge, were evaluated using 21 dogs' spleens. The two-layer gelatin sheet and gelatin sponge exhibited superior hemostatic effects (100% hemostasis completed) compared with TachoSil (0-17% hemostasis). The gelatin matrix immediately absorbed blood flowing from wounds and activated the autologous components in the absorbed blood that promoted coagulation at the bleeding site. The two-layer gelatin sheet had the best surgical handling among the evaluated materials. Materials made of gelatin were associated with fewer inflammatory reactions compared with materials of TachoSil. The two-layer sheet of gelatin is a useful topical agent because of its superior hemostatic effects and usability, and is associated with a lower risk of transmitting diseases and inflammatory reactions. Copyright © 2016. Published by Elsevier Taiwan.
Directory of Open Access Journals (Sweden)
P. L. Read
2009-08-01
Full Text Available Synchronization is studied using a pair of diffusively-coupled, two-layer quasi-geostrophic systems each comprising a single baroclinic wave and a zonal flow. In particular, the coupling between the systems is in the well-known master-slave or one-way configuration. Nonlinear time series analysis, phase dynamics, and bifurcation diagrams are used to study the dynamics of the coupled system. Phase synchronization, imperfect synchronization (phase slips, or complete synchronization are found, depending upon the strength of coupling, when the systems are either in a periodic or a chaotic regime. The results of investigations when the dynamics of each system are in different regimes are also presented. These results also show evidence of phase synchronization and signs of chaos control.
Compartmentalized Fluid Flow In The Nevado Del Ruiz Volcano Hydrothermal System(S)
Zuluaga, C. A.; Mejia, E.
2011-12-01
Combination of several extensive and compressive fault/fracture systems with different lithologic units compartmentalized the hydrothermal system(s) in the vicinity of the Nevado del Ruiz volcano. Three main fault/fracture systems are observed in the Ruiz volcano area, a N10°-20°E system (San Jerónimo and Palestina faults), a N40°-60°W system (Villamaría-Termales, San Ramón, Nereidas, Río Claro, San Eugenio and Campoalegrito faults), and a N60°-80°E system (Santa Rosa fault). The NW trend system act as the main path for fluid circulation, location of faults and fractures belonging to this system and their intersections with other fault systems and/or with lithologic contacts control hot springs location. The observed fault location and hot spring location pattern allow to subdivide the hydrothermal system(s) in at least five blocks. In the southernmost block, hot springs are mostly located in one of the four quadrants originated by fault intersections suggesting that there is a compartmentalization into higher and lower permeability quadrants. It is still unknown if all blocks belong to the same hydrothermal system or if there is more than one hydrothermal system.
Establishment of a Cutting Fluid Control System (Phase III)
1982-09-01
usually takes two to five days. If a crystalline or extremely gummy residue is formed, this fluid should be discarded from further testing. After...REFERENCES 1. "Fishtail Defects in Bearing Races - Their Origin and Elimination," C. F. Barth, TRW TM-4713, December 1972. 2. "Elimination of...Fishtail Defects in Bearing Races Through Optimized Grinding Procedures," C. F. Barth, TRW TM-4768, November 1974. 3. "fhe Nature of Surface Finish
Brake Fluid Compatibility Studies with Advanced Brake Systems
2016-01-16
identified as silane based compounds. Therefore, we can eliminate brake fluid polymerization as a possible cause since no siloxane based polymers were...cm-1 indicate presence of O-H peak corresponding UNCLASSIFIED DRAFT UNCLASSIFIED 21 to water ; 1631.50 cm-1 indicate presence of C=C peak...measurements are usually made using an auxiliary liquid with a known density. In this case, water is used as the auxiliary liquid. The weight of the o
Single Neuron PID Control of Aircraft Deicing Fluids Rapid Heating System
Directory of Open Access Journals (Sweden)
Bin Chen
2013-02-01
Full Text Available Aircraft deicing fluids rapid heating system is widely used in aircraft ground deicing to ensure that the operation of flights can be safe and efficient. Aiming at the temperature turbulence problem of aircraft deicing system, this paper presents the single neuron PID control strategy which combine the advantage of conventional PID control with artificial neuron control. The aircraft deicing fluids rapid heating system and the scheme and working principle of the system is introduced. Simulation is executed on the basis of the mathematical model of aircraft deicing fluids rapid heating system, which is built in this paper, according to a number of data collected by experiments which are operated on the experimental platform of deicing fluids rapid heating system. The simulation results show that the single neuron PID control strategy perform effectively on the temperature turbulence problem of aircraft deicing fluids rapid heating system. Experiments are conducted to vertify the single neuron PID control strategy, the results of which show that the single neuron PID control strategy can achieve the request in practical application of the aircraft deicing fluids rapid heating system.
Heterogeneous Atomistic-Continuum Methods for Dense Fluid Systems
Hadjiconstantinou, Nicolas; Patera, Anthony
1997-08-01
We present new results obtained using the formulation and numerical solution procedure for heterogeneous atomistic--continuum representations of fluid flows presented in [1]. The ingredients are, from the atomistic side, non-equilibrium molecular dynamics, and from the continuum side, finite element solution; the matching is provided by a classical procedure, the Schwarz alternating method with overlapping subdomains. The technique is applied to the flow of two immiscible fluids in a microscale channel. The problem "presents" a particular modelling challenge because of the stress singularity at the moving contact line which is usually relieved through ad hoc methods, the most popular of which is the assumption of slip close to the contact line. The Heterogeneous method properly addresses the problem by treating the region near the contact line with molecular dynamics. References 1. Hadjiconstantinou N., Patera, A.T., Proceedings of the Sixth International Conference on Discrete Models for Fluid Mechanics, To appear as a special edition of the International Journal of Modern Physics C.
Energy Technology Data Exchange (ETDEWEB)
Furusho, J. [The Univ. of Electric Communications, Tokyo (Japan)
1995-09-10
ER fluids (electrorheological fluids) are fluids whose rheological properties vary due to an electric field, and at the present, its development is being vigorously carried forward with the objective of its application to various mechanical systems. The ER fluids which are the objects for its development are two kinds, namely ER suspensions and homogeneous fluids using liquid crystals. Concerning the ER suspensions, its study started from the latter half of 1940`s, but the history of studying the homogeneous ER fluids is short. In this article, comparison is made between the ER suspensions and the homogeneous ER fluids. Regarding the comparison in their application fields, several differences are enumerated including that the response time of the ER suspensions to the change of the electric field is considerably faster than the homogeneous fluids using liquid crystals. As examples of the application of the ER suspensions, ER valves, application to automobiles, ER dampers, vibration control of structures, and ER clutches are shown and likewise, as examples of the application of the homogeneous ER fluids, robot arm control, dampers, etc.. Also its application to robotics is described. 51 refs., 8 figs., 1 tab.
Single-layer versus two-layer stamps for reduced pressure thermal nanoimprint
Papenheim, Marc; Dhima, Khalid; Wang, Si; Steinberg, Christian; Scheer, Hella-Christin
2015-11-01
Low-pressure imprint is interesting to avoid stamp deformation, stamp failure as well as polymer recovery. When large-area stamps are prepared with a stepping procedure, low pressure is required to optimize the stitching. However, with low-pressure imprint, conformal contact between stamp and substrate is critical. Admittedly, the imprint pressure required for conformal contact depends on the stamp material and its thickness. To get an idea to which extent the imprint pressure can be reduced with a flexible stamp, we compared different stamp materials and stamp architectures, single-layer stamps and two-layer stamps. The two-layer stamps are replica stamps, where the structures were replicated in a thin layer of OrmoStamp, fixed by a backplane. On the background of plate theory, we deduce the pressure reduction compared to a Si stamp by calculating the respective pressure ratio, independent from geometries. In addition, temperature-induced issues are addressed which are of relevance for a thermal imprint process. These issues are related to the mismatch between the thermal expansion coefficients of the stamp and the substrate, and in case of a two-layer stamp, to the mismatch between the backplane material and the top layer. The latter results in temperature-induced stamp bending. On the basis of simple analytical calculations, the potential of single-layer stamps and two-layer stamps with respect to thermal imprint at reduced pressure is discussed and guidelines are provided to assess the imprint situation when replica stamps are used for imprint. The results demonstrate the attractiveness of two-layer stamps for reduced pressure nanoimprint, even in a temperature-based process.
Bianchi - Euler system for relativistice fluids and Bel - Robinson type energy
Choquet-Bruhat, Y; Choquet-Bruhat, Yvonne; York, James W.
2002-01-01
We write a first order symmetric hyperbolic system coupling the Riemann with the dynamical acceleration of a relativistic fluid. W determine the associated, coupled, Bel - Robinson energy, and the integral equality that it satisfies.
Energy Technology Data Exchange (ETDEWEB)
Pruess, Karsten
2007-04-13
Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermaldepletion.
elVis: An Interactive System For Visualization of Unsteady Fluid Flow
Gerald-Yamasaki, Michael; Lasinski, T. A. (Technical Monitor)
1995-01-01
ElVis is a prototype system with allows for the interactive visualization of unsteady fluid flow. The increasing computational power applied to fluid dynamics simulations presents the enormous challenge to the visualization system designer to apply a wide range of technologies to the analysis process with ever increasing demands on performance. Visualization of the results of unsteady fluid flow simulations presents the challenge of exploring very large and complex data sets. Since exploration is a trial and error process, it is of utmost importance that the time required to execute a trial (i.e., create a visualization) be at a minimum in order to provide real time interaction.
Magnetohydrodynamic pump with a system for promoting flow of fluid in one direction
Lemoff, Asuncion V.; Lee, Abraham P.
2010-07-13
A magnetohydrodynamic pump for pumping a fluid. The pump includes a microfluidic channel for channeling the fluid, a MHD electrode/magnet system operatively connected to the microfluidic channel, and a system for promoting flow of the fluid in one direction in the microfluidic channel. The pump has uses in the medical and biotechnology industries for blood-cell-separation equipment, biochemical assays, chemical synthesis, genetic analysis, drug screening, an array of antigen-antibody reactions, combinatorial chemistry, drug testing, medical and biological diagnostics, and combinatorial chemistry. The pump also has uses in electrochromatography, surface micromachining, laser ablation, inkjet printers, and mechanical micromilling.
Mibe, K.; Kawamoto, T.; Ono, S.
2012-12-01
Knowing the chemical compositions of fluid and melt is fundamental in understanding the magma genesis and chemical differentiation in the Earth's interior. We investigated the stability fields of aqueous fluid, silicate melt, and supercritical fluid magma using in-situ x-ray radiography and the second critical endpoint in the system peridotite-H2O was determined to be around 3.8 GPa (Mibe et al., 2007, JGR). Using the quenched recovered samples obtained by Mibe et al. (2007), we determined the chemical compositions of aqueous fluid, silicate melt, and supercritical fluid in the vicinity of the second critical endpoint in the system peridotite-H2O by EPMA analyses. A 10- to 30-μm diameter electron beam was used to obtain the composition of quenched materials from aqueous fluid, silicate melt, and supercritical fluid. The compositions of coexisting aqueous fluid and silicate melt were determined at 3.3 GPa and 3.6 GPa and 1180°C. In both samples, olivine coexists with aqueous fluid and silicate melt. In the run at 3.3 GPa, the composition of aqueous fluid was high-Mg dacitic, whereas the composition of silicate melt was hydrous peridotite. In the run at 3.6 GPa, the composition of aqueous fluid was high-Mg andesitic, whereas the composition of silicate melt was hydrous komatiitic. Although aqueous fluids in both runs are high-Mg, both MgO and FeO preferentially enters into silicate melt compared to aqueous fluid.
Hermanska, M.; Stefansson, A.
2014-12-01
Many active volcanic systems are associated with high-enthalpy geothermal systems. For systems characterized by shallow magmatic intrusions, liquid water often predominates at depth with two-phase fluids, vapor and liquid water, occurring at shallower depth due to depressurization boiling. Close to the intrusion, superheated or supercritical vapor may also occur. The Krafla high-enthalpy geothermal system provides an ideal opportunity to study such volcanic geothermal systems. Over forty wells have been drilled into the system with fluid discharge temperatures of 3200 kJ/kg. In this study, geochemical modelling of multicomponent fluid phases associated with shallow magmatic intrusions were conducted across variable temperature, pressure and enthalpy conditions and the results compared with the fluid geochemistry of the Krafla system. Within the reservoir at geothermal temperatures (250-300°C) liquid water predominates. Under these conditions, the concentrations of most major elements are controlled by equilibrium with secondary minerals. Geochemical modelling and observations at Krafla support these findings. Around the magma intrusions believed to be at shallow depth at Krafla, superheated vapor is formed. Such fluid was discharged by the IDDP-1 well at 450°C and 140 bar. According to the geochemical modelling, superheated vapor is produced upon heat addition by the intrusion to the surrounding geothermal water resulting in boiling to dryness, precipitation of non-volatiles (Si, Fe, Mg, Al, SO4, Na, K, Ca) whereas volatiles (CO2, H2S, Cl, F, B) are unaffected. By mass, quartz is the predominant secondary mineral around the intrusions. The chemical composition of the modelled and observed superheated vapor compared well. Upon ascent and depressurization of the liquid geothermal water and the superheated vapor various processes may occur, including superheated vapor condensation, mixing and depressurization boiling. This leads to formation of two-phase liquid and
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....
Method and apparatus for removing non-condensible gas from a working fluid in a binary power system
Energy Technology Data Exchange (ETDEWEB)
Mohr, Charles M. (Idaho Falls, ID); Mines, Gregory L. (Idaho Falls, ID); Bloomfield, K. Kit (Idaho Falls, ID)
2002-01-01
Apparatus for removing non-condensible gas from a working fluid utilized in a thermodynamic system comprises a membrane having an upstream side operatively connected to the thermodynamic system so that the upstream side of the membrane receives a portion of the working fluid. The first membrane separates the non-condensible gas from the working fluid. A pump operatively associated with the membrane causes the portion of the working fluid to contact the membrane and to be returned to the thermodynamic system.
Numerical Modelling of Ore-forming Dynamics of Fractal Dispersive Fluid Systems
Institute of Scientific and Technical Information of China (English)
邓军; 方云; 杨立强; 杨军臣; 孙忠实; 王建平; 丁式江; 王庆飞
2001-01-01
Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid-rock interaction. It changes components and physico-chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore-forming materials. (3) Gold ore-forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone.
A Cryogenic Fluid System Simulation in Support of Integrated Systems Health Management
Barber, John P.; Johnston, Kyle B.; Daigle, Matthew
2013-01-01
Simulations serve as important tools throughout the design and operation of engineering systems. In the context of sys-tems health management, simulations serve many uses. For one, the underlying physical models can be used by model-based health management tools to develop diagnostic and prognostic models. These simulations should incorporate both nominal and faulty behavior with the ability to inject various faults into the system. Such simulations can there-fore be used for operator training, for both nominal and faulty situations, as well as for developing and prototyping health management algorithms. In this paper, we describe a methodology for building such simulations. We discuss the design decisions and tools used to build a simulation of a cryogenic fluid test bed, and how it serves as a core technology for systems health management development and maturation.
New Simulation Method for Transient Response of Composite Fluid Line Systems
Yoshioka, Muneyuki; Yamazaki, Koji
In the first report on this subject, a new simulation method for obtaining the transient response of composite fluid line systems, such as gas transport networks, air brake systems, pressure instrument lines and pneumatic control systems, has been presented. This simulation is based on the wave diagram of the fluid line system and Brown’s approximate step response of a semi-infinite line. In this report, two kinds of wave reduction techniques are introduced for the effective computation of the transient response. One is the unification of equivalent and similar waves at any junction of lines from different traveling routes. The other is the elimination of small waves attenuated by the partial reflection and the long propagation distance. For computed response examples using these techniques, the step responses of composite fluid line systems (a loop line system and multiline branching systems) are also presented.
Phase equilibria in fluid mixtures at high pressures: The He-CH4 system
Streett, W. B.; Erickson, A. L.; Hill, J. L. E.
1972-01-01
An experimental study of phase equilibria in the He-CH4 system was carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These results, together with those recently obtained for other binary systems, provide information about the form of phase diagrams for binary gas mixtures in the region of pressure induced phase transitions at high pressures. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.
Institute of Scientific and Technical Information of China (English)
Jing Tang Xing
2008-01-01
A fluid-structure interaction system subject to Sommerfeld's condition is defined as a Sommerfeld system which is divided into three categories:Fluid Sommerfeld(FS)System,Solid Sommerfeld(SS)System and Fluid Solid Sommerfeld(FSS)System of which Sommerfeld conditions are imposed on a fluid boundary only,a solid boundary only and both fluid and solid boundaries,respectively.This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems.A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves.The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above.These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering.
Taetz, Stephan; John, Timm; Bröcker, Michael; Spandler, Carl; Stracke, Andreas
2017-04-01
A better understanding of the subduction zone fluid cycle and its mechanical feedback requires in-depth knowledge of how fluids flow within and out of the descending slabs. In order to develop reliable quantitative models of fluid flow, the general relationship between dehydration reactions, fluid pathway formation, and the dimensions and timescales of distinct fluid flow events have to be explored. The high-pressure/low-temperature metamorphic rocks of the Pouébo Eclogite Mélange in New Caledonia provide an excellent opportunity to study the fluid flux in a subduction zone setting. Fluid dynamics are recorded by high-pressure veins that cross-cut eclogite facies mélange blocks from this occurrence. Two types of garnet-quartz-phengite veins can be distinguished. These veins record both synmetamorphic internal fluid release by mineral breakdown reactions (type I veins) as well as infiltration of an external fluid (type II veins) and the associated formation of a reaction halo. The overall dehydration, fluid accumulation and fluid migration documented by the type I veins occurred on a timescale of 10^5-106 years that is mainly given by the geometry and convergence rate of the subduction system. In order to quantify the timeframe of fluid-rock interaction between the external fluid and the wall-rock, we have applied Li-isotope chronology. A continuous profile was sampled perpendicular to a type II vein including material from the vein, the reaction selvage and the immediate host rock. Additional drill cores were taken from parts of the outcrop that most likely remained completely unaffected by fluid infiltration-induced alteration. Different Li concentrations in the internal and external fluid reservoirs produced a distinct diffusion profile of decreasing Li concentration and increasing δ7Li as the reaction front propagated into the host-rock. Li-chronometric constraints indicate that fluid-rock interaction related to the formation of the type II veins and had
Concentration-Dependent Diffusion Instability in Reactive Miscible Fluids
Bratsun, Dmitry; Mizev, Alexey; Mosheva, Elena
2015-01-01
We report new chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with the frontal acid-base neutralization can give rise to formation of the local unstable zone low in density resulting in a perfectly regular cell-type convective pattern. The described effect gives an example of yet another powerful mechanism which allows the reaction-diffusion processes to govern the flow of reacting fluids under gravity condition.
Concentration-dependent diffusion instability in reactive miscible fluids
Bratsun, Dmitry; Kostarev, Konstantin; Mizev, Aleksey; Mosheva, Elena
2015-07-01
We report on chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with frontal acid-base neutralization can give rise to the formation of a local unstable zone low in density, resulting in a perfectly regular cell-type convective pattern. The described effect gives an example of yet another powerful mechanism which allows the reaction-diffusion processes to govern the flow of reacting fluids under gravity conditions.
Bai, Jin Hyoung; Whang, Joo Ho
2011-07-01
This paper proposed the two-layer stack scintillator-coupled photodiode detector to improve the measurement accuracy of the gamma-ray scanning. Both MCNPX and DETECT97 code were used to design the detector. The two manufactured two-layer stack gamma detectors were used to measure the density profile of the distillation column of the radiographic non-intrusive process diagnostic area. To compare the measurement accuracy of the density profile through the non-destructive transmission test, the relative error of the four fluids used for the process diagnostics was analysed. To summarise the measurement results with regard to the relative error of the NaI(Tl) detector and the manufactured detector by material as well as the total relative error, the total relative error of the NaI(Tl) detector was about 15.7 %, whereas that of the two-layer stack CsI(Tl) with photodiode detectors were about 5 %. This paper confirmed that the measurement accuracy of the detector proposed was improved by about three times as compared with the NaI(Tl) detector mostly used for non-destructive testing.
Analysis of Two-Layered Random Interfaces for Two Dimensional Widom-Rowlinson's Model
Directory of Open Access Journals (Sweden)
Jun Wang
2011-01-01
Full Text Available The statistical behaviors of two-layered random-phase interfaces in two-dimensional Widom-Rowlinson's model are investigated. The phase interfaces separate two coexisting phases of the lattice Widom-Rowlinson model; when the chemical potential μ of the model is large enough, the convergence of the probability distributions which describe the fluctuations of the phase interfaces is studied. In this paper, the backbones of interfaces are introduced in the model, and the corresponding polymer chains and cluster expansions are developed and analyzed for the polymer weights. And the existence of the free energy for two-layered random-phase interfaces of the two-dimensional Widom-Rowlinson model is given.
A Two-layer Model for the Simulation of the VARTM Process with Resin Distribution Layer
Young, Wen-Bin
2013-12-01
Vacuum assisted resin transfer molding (VARTM) is one of the important processes to fabricate high performance composites. In this process, resin is drawn into the mold to impregnate the fiber reinforcement to a form composite. A resin distribution layer with high permeability was often introduced on top of the fiber reinforcement to accelerate the filling speed. Due to the difference of the flow resistance in the resin distribution layer and the reinforcement as well as the resulting through thickness transverse flow, the filling flow field is intrinsically three-dimensional. This study developed a two-layer model with two-dimensional formulation to simulate the filling flow of the VARTM process with a resin distribution layer. Two-dimensional flow was considered in each layer and a transverse flow in the thickness direction was estimated between the two layers. Thermal analysis including the transverse convection was also performed to better simulate the temperature distribution.
TAILING WAVETRAIN GENERATION IN PRECURSOR SOLITON GENERATION IN TWO-LAYER FLOW
Institute of Scientific and Technical Information of China (English)
Xu Zhaoting; Xu Hao; Samuel Shan-pu Shen
2000-01-01
A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations(AKdV),which are derived by the authors in terms of Whitham's method of averaging[1,2].From the AKdV equations,group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains,furthermore an analytical solution of the tailing wavetrain generation is found theoretically.A comparison between the theoretical and numerical results is carried out in the present paper,which shows that the theoretical results are in good agreement with the numerical ones,obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.
A fluid collection system for dermal wounds in clinical investigations.
Klopfer, Michael; Banyard, Derek; Li, G-P; Widgerow, Alan; Bachman, Mark
2016-03-01
In this work, we demonstrate the use of a thin, self adherent, and clinically durable patch device that can collect fluid from a wound site for analysis. This device is manufactured from laminated silicone layers using a novel all-silicone double-molding process. In vitro studies for flow and delivery were followed by a clinical demonstration for exudate collection efficiency from a clinically presented partial thickness burn. The demonstrated utility of this device lends itself for use as a research implement used to clinically sample wound exudate for analysis. This device can serve as a platform for future integration of wearable technology into wound monitoring and care. The demonstrated fabrication method can be used for devices requiring thin membrane construction.
Naruse, Makoto; Ishii, Satoshi; Drezet, Aurélien; Huant, Serge; Hoga, Morihisa; Ohyagi, Yasuyuki; Matsumoto, Tsutomu; Tate, Naoya; Ohtsu, Motoichi
2014-01-01
We theoretically demonstrate direction-dependent polarization conversion efficiency, yielding unidirectional light transmission, through a two-layer nanostructure by using the angular spectrum representation of optical near-fields. The theory provides results that are consistent with electromagnetic numerical simulations. This study reveals that optical near-field interactions among nanostructured matter can provide unique optical properties, such as the unidirectionality observed here, and offers fundamental guiding principles for understanding and engineering nanostructures for realizing novel functionalities.
Two-layer cold storage method for pancreas and islet cell transplantation
Institute of Scientific and Technical Information of China (English)
Yasuhiro; Fujino
2010-01-01
The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging ...
SH-TM mathematical analogy for the two-layer case. A magnetotellurics application
J. Carcione; F. Poletto
2017-01-01
The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission) problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised) and TM (transverse-magnetic) waves. In particular, w...
On Theory of Dispersive Transport in a Two-Layer Polymer Structure
Sibatov, R. T.; Morozova, E. V.
2016-09-01
Dispersive transport of charge carriers in a two-layer polymer structure is modeled on the basis of the integrodifferential equation of hereditary diffusion. The model of multiple trapping in a bilayer is generalized to the case of an arbitrary density of localized states. With the help of an efficient Monte Carlo algorithm, curves of the transient current are calculated and their features are explained within the framework of a stochastic interpretation of the process.
On two-layer models and the similarity functions for the PBL
Brown, R. A.
1982-01-01
An operational Planetary Boundary Layer model which employs similarity principles and two-layer patching to provide state-of-the-art parameterization for the PBL flow is used to study the popularly used similarity functions, A and B. The expected trends with stratification are shown. The effects of baroclinicity, secondary flow, humidity, latitude, surface roughness variation and choice of characteristic height scale are discussed.
Two-layer cold storage method for pancreas and islet cell transplantation
Fujino, Yasuhiro
2010-01-01
The two-layer cold storage method (TLM) was first reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins’ solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storag...
A Two Layer Approach to the Computability and Complexity of Real Functions
DEFF Research Database (Denmark)
Lambov, Branimir Zdravkov
2003-01-01
We present a new model for computability and complexity of real functions together with an implementation that it based on it. The model uses a two-layer approach in which low-type basic objects perform the computation of a real function, but, whenever needed, can be complemented with higher type...... in computable analysis, while the efficiency of the implementation is not compromised by the need to create and maintain higher-type objects....
Kleis, Stanley J.; Truong, Tuan; Goodwin, Thomas J,
2004-01-01
This report is a documentation of a fluid dynamic analysis of the proposed Automated Static Culture System (ASCS) cell module mixing protocol. The report consists of a review of some basic fluid dynamics principles appropriate for the mixing of a patch of high oxygen content media into the surrounding media which is initially depleted of oxygen, followed by a computational fluid dynamics (CFD) study of this process for the proposed protocol over a range of the governing parameters. The time histories of oxygen concentration distributions and mechanical shear levels generated are used to characterize the mixing process for different parameter values.
Wang, Gang; Wu, Nanhua; Chen, Jionghua; Wang, Jinjian; Shao, Jingling; Zhu, Xiaolei; Lu, Xiaohua; Guo, Lucun
2016-11-01
The thermodynamic and kinetic behaviors of gold nanoparticles confined between two-layer graphene nanosheets (two-layer-GNSs) are examined and investigated during heating and cooling processes via molecular dynamics (MD) simulation technique. An EAM potential is applied to represent the gold-gold interactions while a Lennard-Jones (L-J) potential is used to describe the gold-GNS interactions. The MD melting temperature of 1345 K for bulk gold is close to the experimental value (1337 K), confirming that the EAM potential used to describe gold-gold interactions is reliable. On the other hand, the melting temperatures of gold clusters supported on graphite bilayer are corrected to the corresponding experimental values by adjusting the εAu-C value. Therefore, the subsequent results from current work are reliable. The gold nanoparticles confined within two-layer GNSs exhibit face center cubic structures, which is similar to those of free gold clusters and bulk gold. The melting points, heats of fusion, and heat capacities of the confined gold nanoparticles are predicted based on the plots of total energies against temperature. The density distribution perpendicular to GNS suggests that the freezing of confined gold nanoparticles starts from outermost layers. The confined gold clusters exhibit layering phenomenon even in liquid state. The transition of order-disorder in each layer is an essential characteristic in structure for the freezing phase transition of the confined gold clusters. Additionally, some vital kinetic data are obtained in terms of classical nucleation theory.
Long-term persistence of oil from the Exxon Valdez spill in two-layer beaches
Li, Hailong; Boufadel, Michel C.
2010-02-01
Oil spilled from the tanker Exxon Valdez in 1989 (refs 1, 2) persists in the subsurface of gravel beaches in Prince William Sound, Alaska. The contamination includes considerable amounts of chemicals that are harmful to the local fauna. However, remediation of the beaches was stopped in 1992, because it was assumed that the disappearance rate of oil was large enough to ensure a complete removal of oil within a few years. Here we present field data and numerical simulations of a two-layered beach with a small freshwater recharge in the contaminated area, where a high-permeability upper layer is underlain by a low-permeability lower layer. We find that the upper layer temporarily stored the oil, while it slowly and continuously filled the lower layer wherever the water table dropped below the interface of the two layers, as a result of low freshwater recharge from the land. Once the oil entered the lower layer, it became entrapped by capillary forces and persisted there in nearly anoxic conditions that are a result of the tidal hydraulics in the two-layered beaches. We suggest that similar dynamics could operate on tidal gravel beaches around the world, which are particularly common in mid- and high-latitude regions, with implications for locating spilled oil and for its biological remediation.
A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves
Lee, V.; Payne, A. J.; Gregory, J. M.
2011-01-01
We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer. The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.
A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves
Directory of Open Access Journals (Sweden)
V. Lee
2011-01-01
Full Text Available We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer.
The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.
Phase equilibria in fluid mixtures at high pressures - The He-CH4 system.
Streett, W. B.; Erickson, A. L.; Hill, J. L. E.
1972-01-01
An experimental study of phase equilibria in the He-CH4 system has been carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.-
Surfactant and gravity dependent instability of two-layer Couette flows and its nonlinear saturation
Frenkel, Alexander L
2016-01-01
A horizontal flow of two immiscible fluid layers with different densities, viscosities and thicknesses, subject to vertical gravitational forces and with an insoluble surfactant present at the interface, is investigated. The base Couette flow is driven by the horizontal motion of the channel walls. Linear and nonlinear stages of the (inertialess) surfactant and gravity dependent long-wave instability are studied using the lubrication approximation, which leads to a system of coupled nonlinear evolution equations for the interface and surfactant disturbances. The linear stability is determined by an eigenvalue problem for the normal modes. The growth rates and the amplitudes of disturbances of the interface, surfactant, velocities, and pressures are found analytically. For each wavenumber, there are two active normal modes. For each mode, the instability threshold conditions in terms of the system parameters are determined. In particular, it transpires that for certain parametric ranges, even arbitrarily stron...
The simplest model for non-congruent fluid-fluid phase transition in Coulomb system
Stroev, Nikita
2015-01-01
The simplest model for non-congruent phase transition of gas-liquid type was developed in frames of modified model with no associations of a binary ionic mixture (BIM) on a homogeneous compressible ideal background (or non-ideal) electron gas /BIM($\\sim$)/. The analytical approximation for equation of state equation of state of Potekhin and Chabrier of fully ionized electron-ionic plasma was used for description of the ion-ion correlations (Coulomb non-ideality) in combination with ``linear mixture'' (LM) approximation. Phase equilibrium for the charged species was calculated according to the Gibbs-Guggenheim conditions. The presently considered BIM($\\sim$) model allows to calculate full set of parameters for phase boundaries of non-congruent variant of phase equilibrium and to study all features for this non-congruent phase transition realization in Coulomb system in comparison with the simpler (standard) forced-congruent evaporation mode. In particular, in BIM($\\sim$) there were reproduced two-dimensional r...
Modeling Two-Phase Flow and Vapor Cycles Using the Generalized Fluid System Simulation Program
Smith, Amanda D.; Majumdar, Alok K.
2017-01-01
This work presents three new applications for the general purpose fluid network solver code GFSSP developed at NASA's Marshall Space Flight Center: (1) cooling tower, (2) vapor-compression refrigeration system, and (3) vapor-expansion power generation system. These systems are widely used across engineering disciplines in a variety of energy systems, and these models expand the capabilities and the use of GFSSP to include fluids and features that are not part of its present set of provided examples. GFSSP provides pressure, temperature, and species concentrations at designated locations, or nodes, within a fluid network based on a finite volume formulation of thermodynamics and conservation laws. This paper describes the theoretical basis for the construction of the models, their implementation in the current GFSSP modeling system, and a brief evaluation of the usefulness of the model results, as well as their applicability toward a broader spectrum of analytical problems in both university teaching and engineering research.
Polydispersity effect on solid-fluid transition in hard sphere systems
Nogawa, T.
2010-02-01
The solid-fluid transition of the hard elastic particle system with size polydispersity is studied by molecular dynamics simulations. Using nonequilibrium relaxation from the mixed initial condition we determines the melting point where the first order transition between the solid, fcc crystal, and fluid states occurs. It is found that the density gap between the bistable states decreases with increasing the strength of the polydispersity and continuously approaches to zero at the critical point. © 2010.
Numerical Modeling of Multiphase Fluid Flow in Ore-Forming Hydrothermal Systems
Weis, P.; Driesner, T.; Coumou, D.; Heinrich, C. A.
2007-12-01
Two coexisting fluid phases - a variably saline liquid and a vapor phase - are ubiquitous in ore-forming and other hydrothermal systems. Understanding the dynamics of phase separation and the distinct physical and chemical evolution of the two fluids probably plays a key role in generating different ore deposit types, e.g. porphyry type, high and low sulfidation Cu-Mo-Au deposits. To this end, processes within hydrothermal systems have been studied with a refined numerical model describing fluid flow in transient porous media (CSP~5.0). The model is formulated on a mass, energy and momentum conserving finite-element-finite-volume (FEFV) scheme and is capable of simulating multiphase flow of NaCl-H20 fluids. Fluid properties are computed from an improved equation of state (SOWAT~2.0). It covers conditions with temperatures of up to 1000 degrees~C, pressures of up to 500 MPa, and fluid salinities of 0~to 100%~NaCl. In particular, the new set-up allows for a more accurate description of fluid phase separation during boiling of hydrothermal fluids into a vapor and a brine phase. The geometric flexibility of the FEFV-meshes allows for investigations of a large variety of geological settings, ranging from ore-forming processes in magmatic hydrothermal system to the dynamics of black smokers at mid-ocean ridges. Simulations demonstrated that hydrothermal convection patterns above cooling plutons are primarily controlled by the system-scale permeability structure. In porphyry systems, high fluid pressures develop in a stock rising from the magma chamber which can lead to rock failure and, eventually, an increase in permeability due to hydrofracturing. Comparisons of the thermal evolution as inferred from modeling studies with data from fluid inclusion studies of the Pb-Zn deposits of Madan, Bulgaria are in a strikingly good agreement. This indicates that cross-comparisons of field observations, analytical data and numerical simulations will become a powerful tool towards a
Fluid-structure interaction in BWR suppression pool systems. Final report. [PELE-IC code
Energy Technology Data Exchange (ETDEWEB)
Nickell, R.E.
1979-09-01
The discharge of safety relief valves or a severe loss-of-coolant event in a boiling-water-cooled reactor steam supply system triggers a complex pressure suppression system that is based upon sub-surface steam condensation in large pools of water. The physical problems fall into two categories. The first is referred to as vent clearing and describes the process of expelling non-condensables from the system prior to steam flow. The second category covers a variety of phenomena related to the transient overexpansion of a condensable volume and the subsequent inertially-driven volume decrease. The dynamic loading of either event, depending upon fluid-structural design parameters, can be of concern in safety analysis. This report describes the development of a method for calculating the loads and the structural response for both types of problems. The method is embedded in a computer code, called PELE-IC, that couples a two-dimensional, incompressible eulerian fluid algorithm to a finite element shell algorithm. The fluid physics is based upon the SOLA algorithm, which provideds a trial velocity field using the Navier-Stokes equations that is subsequently corrected iteratively so that incompressibility, fluid-structure interface compatibility, and boundary conditions are satisfied. These fluid and fluid-structure algorithms have been extensively verified through calculations of known solutions from the classical literature, and by comparison to air and steam blowdown experiments.
Performance of EDAB-HCl Acid Blended System as Fracturing Fluids in Oil Fields
Institute of Scientific and Technical Information of China (English)
赵增迎; 吕国诚; 张以河; 连胜江; 田娜
2014-01-01
Due to the high price and formation damage of the guargum fracturing fluid, many oilfields are more and more interested in surfactant based fracturing fluids. The rheological properties of erucicamide dimethyl ami-dopropyl betaine (EDAB)-HCl acid blended system and its suitability as fracturing fluid were investigated in this work. The effects of pH, concentration of EDAB, and temperature on the rheological properties of the blended sys-tem were studied. The results show that addition of EDAB improved the viscosity of the system from less than 10 mPa·s to about 400 mPa·s, which could retard the acid-rock reaction to about one half at 60 °C and one quarter at 90 °C comparing to straight HCl acid, suggesting that there is sufficient time for the blended fluid to react with for-mation rock when it is used as fracturing fluid in an oil field. Core flow tests demonstrated that the EDAB-acid blended fluid could divert itself from high permeability formation core to low permeability one, thus ensuring proper acid placement in the target reservoirs.
Experimental study on high viscosity fluid micro-droplet jetting system
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Fluid dispensing is a method by which fluid materials(such as epoxy,adhesive,and encapsulant) are delivered in a controlled manner in electronics packaging.Fluid jetting,derived from inkjet technology,is a noncontact,data-driven fluid dispensing technology.But ideal fluid materials for packaging are usually high viscous,which is difficult to realize by traditional inkjet technology.In this paper,a mechanical micro-droplet jetting system for high viscosity fluid was proposed.It consists of dispensing valve,motion stage,temperature control subsystem,pneumatic subsystem,driving circuit for solenoid valve,and system control software.Performance of this system under various circumstances was studied by changing several parameters,including working temperature,stroke length,back pressure and drive pulse width.Tiny droplets of 0.35 mm in diameter were produced by stainless steel nozzle of 0.2 mm in diameter in the experimental study.
Modular microfluidic systems using reversibly attached PDMS fluid control modules
DEFF Research Database (Denmark)
Skafte-Pedersen, Peder; Sip, Christopher G.; Folch, Albert;
2013-01-01
The use of soft lithography-based poly(dimethylsiloxane) (PDMS) valve systems is the dominating approach for high-density microscale fluidic control. Integrated systems enable complex flow control and large-scale integration, but lack modularity. In contrast, modular systems are attractive altern...
Development of fluid system design technology for integral reactor
Energy Technology Data Exchange (ETDEWEB)
Lee, D. J.; Chang, M. H.; Kang, D. J. and others
1999-03-01
This study presents the technology development of the system design concepts of SMART, a multi-purposed integral reactor with enhanced safety and operability, for use in diverse usages and applications of the nuclear energy. This report contains the following; - Design characteristics - Performance and safety related design criteria - System description: Primary system, Secondary system, Residual heat removal system, Make-up system, Component cooling system, Safety system - Development of design computer code: Steam generator performance(ONCESG), Pressurizer performance(COLDPZR), Steam generator flow instability(SGINS) - Development of component module and modeling using MMS computer code - Design calculation: Steam generator thermal sizing, Analysis of feed-water temperature increase at a low flow rate, Evaluation of thermal efficiency in the secondary system, Inlet orifice throttling coefficient for the prevention of steam generator flow instability, Analysis of Nitrogen gas temperature in the pressurizer during heat-up process, evaluation of water chemistry and erosion etc. The results of this study can be utilized not only for the foundation technology of the next phase basic system design of the SMART but also for the basic model in optimizing the system concepts for future advanced reactors. (author)
A novel technique for chest drain removal using a two layer method with triclosan-coated sutures
Yokoyama, Yujiro; Nakagomi, Takahiro; Shikata, Daichi
2017-01-01
In thoracic surgery, a thoracic drain is always inserted after the surgical procedure. Repair of the wound after removal of the thoracic tube is performed postoperatively, but no universally standard methods currently exists for this tube removal. Here we report a technique using triclosan-coated sutures that is used in thoracic surgery in our hospital. There are several advantages of this technique. First, there is no need for stitches removal on follow-up. Second, it prevents the leakage of pleural exudate because of the tight two-layer sutures. In addition, it was observed to be superior in terms of both wound healing and cosmetic aspects, due to the layer-to-layer sutures. The use of triclosan-coated sutures helps prevent infection and empyema is quite unlikely to occur as the result of the tight ligating of the muscular layer using these sutures. We applied this method in 168 patients over a period of 24 months. There were no complications on removal of the chest tube such as infection, fluid leakage or opening of the surgical wound. PMID:28203426
The Development of Electrorheological Fluids for AN Automotive Semi-Active Suspension System
Weyenberg, Thomas R.; Pialet, Joseph W.; Petek, Nicholas K.
The feasibility of electrorheological (ER) dampers for an automotive semi-active suspension was evaluated in a three phase program. In the first phase, ER fluid performance targets were derived. The desired ride and handling attributes of the suspension system were translated into damper specifications, which were then translated into the ER fluid performance targets. The damper specifications included dynamic range, bandwidth, power draw, and packaging. The ER fluid performance parameters then included zero-field viscosity, ER stress, response time, and power density. In the second phase, the dampers and the ER fluid were developed to meet the performance targets. Trade-offs were made between damper design and fluid formulation to achieve the desired damper dynamic range and power draw. A state-diagram approach using screen test data was used to select candidate ER fluids. In the third phase of the program, a prototype semi-active suspension system using fast, continuously variable ER dampers was installed on a demonstration vehicle. Heave, pitch, and roll motions of the vehicle were controlled by applying voltages independently to the four dampers as determined by a modified sky-hook algorithm. The system was designed to respond in less than 10 ms with an average power requirement less than 40 W for normal road surfaces and handling. Laboratory data from a pressure driven flow screen test and a damper test are presented that document the ER fluid performance specification and selection process. Vehicle performance data are presented that demonstrate the features of ER technology for the semi-active suspension application. Remaining issues for commercialization of ER fluids are discussed.
Groves, Curtis Edward
2014-01-01
Spacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data. Quantifying the uncertainty in analytical predictions is imperative to the success of any simulation-based product. The method could provide an alternative to traditional validation by test only mentality. This method could be extended to other disciplines and has potential to provide uncertainty for any numerical simulation, thus lowering the cost of performing these verifications while increasing the confidence in those predictions.Spacecraft requirements can include a maximum airflow speed to protect delicate instruments during ground processing. Computational Fluid Dynamics can be used to verify these requirements; however, the model must be validated by test data. This research includes the following three objectives and methods. Objective one is develop, model, and perform a Computational Fluid Dynamics analysis of three (3) generic, non-proprietary, environmental control systems and spacecraft configurations. Several commercially available and open source solvers have the capability to model the turbulent, highly three-dimensional, incompressible flow regime. The proposed method uses FLUENT, STARCCM+, and OPENFOAM. Objective two is to perform an uncertainty analysis of the Computational Fluid Dynamics model using the methodology found in Comprehensive Approach to Verification and Validation of Computational Fluid Dynamics Simulations. This method requires three separate grids and solutions, which quantify the error bars around Computational Fluid Dynamics predictions
Groves, Curtis Edward
2014-01-01
Spacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data. Quantifying the uncertainty in analytical predictions is imperative to the success of any simulation-based product. The method could provide an alternative to traditional "validation by test only" mentality. This method could be extended to other disciplines and has potential to provide uncertainty for any numerical simulation, thus lowering the cost of performing these verifications while increasing the confidence in those predictions. Spacecraft requirements can include a maximum airflow speed to protect delicate instruments during ground processing. Computational Fluid Dynamics can be used to verify these requirements; however, the model must be validated by test data. This research includes the following three objectives and methods. Objective one is develop, model, and perform a Computational Fluid Dynamics analysis of three (3) generic, non-proprietary, environmental control systems and spacecraft configurations. Several commercially available and open source solvers have the capability to model the turbulent, highly three-dimensional, incompressible flow regime. The proposed method uses FLUENT, STARCCM+, and OPENFOAM. Objective two is to perform an uncertainty analysis of the Computational Fluid Dynamics model using the methodology found in "Comprehensive Approach to Verification and Validation of Computational Fluid Dynamics Simulations". This method requires three separate grids and solutions, which quantify the error bars around Computational Fluid Dynamics
Fluid chemistry evolution and mineral deposition in the main-stage Creede epithermal system
Plumlee, G.S.
1994-01-01
This paper presents results of chemical speciation and reaction path calculations that model fluid chemistry evolution and ore deposition in the main-stage Creede, Colorado, epithermal system. An extensive geologic, mineralogic, and geochemical framework for mineralization has been developed by many researchers for the central and southern district vein systems (OH and P veins; central and southern Amethyst and Bulldog Mountain vein systems) and is used to constrain and guide the modeling presented in this paper. Modeling results for Creede and other epithermal fluid compositions show that epithermal ore grades, mineral assemblages, and mineral zoning patterns are strongly influenced by shallow hydrologic processes such as boiling and fluid mixing. As a result, epithermal mineral assemblages and zoning patterns can be used to reconstruct the paleohydrology of the hydrothermal systems from which they were deposited, and thus provide useful tools for epithermal ore exploration -from Author
Reducing Fatigue Loading Due to Pressure Shift in Discrete Fluid Power Force Systems
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen
2016-01-01
Discrete Fluid Power Force Systems is one of the topologies gaining focus in the pursuit of lowering energy losses in fluid power transmission systems. The cylinder based Fluid Power Force System considered in this article is constructed with a multi-chamber cylinder, a number of constant pressure...... power force system. The current paper investigates the correlation between pressure oscillations in the cylinder chambers and valve flow in the manifold. Furthermore, the correlation between the pressure shifting time and the pressure overshoot is investigated. The study therefore focus on how to shape...... the valve flow in the manifold to reduce the added fatigue loads. A simple transmission line model is developed for the analysis. Two inputs are given in the Laplace domain and the time domain solution of the cylinder pressure to the given inputs are derived through inverse Laplace transformation. Based...
Fluid storage and transport in thrust belts: the Gavarnie Thrust system revisited
McCaig, Andrew
2015-04-01
There has been renewed interest in the pressure and movement of fluids in thrust systems in recent years with the discovery and increasing importance of slow slip earthquakes. Unfortunately the overpressured regime thought to be the source region for both normal and slow-slip earthquakes is inaccessible to direct observation, so information about the actual water content, flow regimes and permeability structure at the time of thrusting can only be obtained in exhumed rocks. The Gavarnie Thrust System in the Pyrenees (including the immediate footwall of the thrust and overlying thrust sheets) is exceptionally well studied in terms of structural and microstructural work, fluid inclusions, and isotopic tracing of fluid flow. Southward thrusting by 12-15 km occurred during the Eocene, and the current geometry of the thrust is a broad dome, allowing sampling at many locations. There is abundant evidence for near-lithostatic fluid pressures at depths of 8-15 km in the crust and temperatures of 300-400 °C, and fluids at these levels are dominated by hypersaline brines with Cl/Br ratios indicating evaporation of seawater. They are inferred to be derived from widespread Triassic evaporates, and stored in underlying redbeds and fractured basement rocks. There is also evidence from fluid inclusions for periodic pressure cycling down to near-hydrostatic values. This is thought to be related to co-seismic fault valve behaviour with release of fluid both into the shallow thrust and into steeply dipping shear zones in the hangingwall. Isotopic studies of carbonate mylonites along the Gavarnie thrust indicate unidirectional southward (structurally upward) flow of fluid , again probably mainly during transient veining events. These relatively slow moving fluids appear to have fed into a hydrostatic regime with topographically driven flow at higher levels. If time averaged permeability was high, most of the fluid would have rapidly escaped, since there is little opportunity to
Low-energy degassing mechanisms for a fluid-based radioxenon detection system
Energy Technology Data Exchange (ETDEWEB)
Russ, W.R.; Stuenkel, D.O.; Valentine, J.D. [Univ. of Cincinnati, OH (United States). Dept. of Mechanical, Industrial and Nuclear Engineering; Gross, K.C. [Argonne National Lab., IL (United States). Reactor Analysis Div.
1998-09-01
A method to concentrate heavy noble gases from the atmosphere using certain organic fluids is being developed. To use this technique in a system to monitor the atmosphere for important noble gas fission products (Xe-131, Xe-131m, Xe-133, Xe-133m, and Xe-135) generated by nuclear testing, the radionuclides captured in the fluid must either be detected in the fluid or degassed. This study presents experimental results for a number of possible degassing methods, including heating bubbling with a purge gas, ultrasonic agitation, vacuum, and combinations thereof. Methods were evaluated for energy and time requirements and dilution of the degas product. Initial experiments indicate that in addition to overcoming the standard desorption process dictated by partial pressures per Henry`s Law, a capture mechanism must also be overcome to degas. Some type of agitation, thermal or mechanical, can be used to release weakly trapped gas atoms from the fluid, while diffusional mass transfer can be enhanced through entrainment with a purge gas or use of a vacuum. Ultrasonic agitation of a thin film in a strong vacuum has been shown to be the most effective method of those tested. Implementation of an efficient degas system, along with an absorption system and radioxenon detector could result in an ultrasensitive fluid-based radioxenon measurement system that is more portable, less expensive, and simpler than charcoal-based systems which use cryogenic techniques.
A new fluid distribution system for scale-flexible expanded bed adsorption
DEFF Research Database (Denmark)
Hubbuch, Jürgen; Heebøll-Nielsen, Anders; Hobley, Timothy John
2002-01-01
A new fluid distribution system designed for expanded bed adsorption was introduced and studied in a 150-cm diameter column. Based on fluid application through a rotating distributor, it eradicates the need for perforated plates, meshes, or local mixers. The effect of rotation rate on column...... change in expansion characteristics as distributor rotation rate was increased from 2.5 to 10 rpm. The distributor was observed to generate a flow pattern suitable for expanded bed adsorption when the supports were fluidized at a superficial fluid velocity of 283 cm (.) h(-1) and dye pulses introduced....... At a rotation rate of 2.5 rpm, no significant dead zones were observed, and a discrete band was formed that moved up through the bed. Furthermore, the pattern of dye movement could be used to calculate interstitial linear fluid velocities of 460 cm (.) h(-1) and 572 cm (.) h(-1) at the column wall and center...
Development of fiber optic sensor for fluid flow of astronauts’ life-support system
Shachneva, E. A.; Murashkina, T. I.
2016-08-01
This paper proposes a fiber optic sensor consumption (volume, speed) of liquids in life-support systems of astronauts, as well as offers a simple method and apparatus for reproducing the parameters of fluid flow needed in research, yustiovke and adjusting the optical sensor system.
Fluid and electrolyte control systems in the human body: A study report
White, R. J.
1973-01-01
Research in the area of modeling of the fluid and electrolyte system is briefly reviewed and a model of this system, which is adequate for a basic description of the requisite physiological processes, is presented. The use of this model as an individual subsystem model and as a component of a more complete human model is discussed.
An Innovative Improvement of Engineering Learning System Using Computational Fluid Dynamics Concept
Hung, T. C.; Wang, S. K.; Tai, S. W.; Hung, C. T.
2007-01-01
An innovative concept of an electronic learning system has been established in an attempt to achieve a technology that provides engineering students with an instructive and affordable framework for learning engineering-related courses. This system utilizes an existing Computational Fluid Dynamics (CFD) package, Active Server Pages programming,…
Groves, Curtis; Ilie, Marcel; Schallhorn, Paul
2014-01-01
Spacecraft components may be damaged due to airflow produced by Environmental Control Systems (ECS). There are uncertainties and errors associated with using Computational Fluid Dynamics (CFD) to predict the flow field around a spacecraft from the ECS System. This paper describes an approach to estimate the uncertainty in using CFD to predict the airflow speeds around an encapsulated spacecraft.
Microcontroller-driven fluid-injection system for atomic force microscopy.
Kasas, S; Alonso, L; Jacquet, P; Adamcik, J; Haeberli, C; Dietler, G
2010-01-01
We present a programmable microcontroller-driven injection system for the exchange of imaging medium during atomic force microscopy. Using this low-noise system, high-resolution imaging can be performed during this process of injection without disturbance. This latter circumstance was exemplified by the online imaging of conformational changes in DNA molecules during the injection of anticancer drug into the fluid chamber.
Inoue, Yuki; Hamada, Takaho; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru
2016-12-01
We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2).
Inoue, Yuki; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru
2016-01-01
We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for the use at cryogenic temperatures in millimeter wave measurements. Thermally- sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background (CMB) polarization measurements, such as POLARBEAR-2 (PB-2).
Yudovsky, Dmitry; Nouvong, Aksone; Schomacker, Kevin; Pilon, Laurent
2010-02-01
Foot ulceration is a debilitating comorbidity of diabetes that may result in loss of mobility and amputation. Optical detection of cutaneous tissue changes due to inflammation and necrosis at the preulcer site could constitute a preventative strategy. A commercial hyperspectral oximetry system was used to measure tissue oxygenation on the feet of diabetic patients. A previously developed predictive index was used to differentiate preulcer tissue from surrounding healthy tissue with a sensitivity of 92% and specificity of 80%. To improve prediction accuracy, an optical skin model was developed treating skin as a two-layer medium and explicitly accounting for (i) melanin content and thickness of the epidermis, (ii) blood content and hemoglobin saturation of the dermis, and (iii) tissue scattering in both layers. Using this forward model, an iterative inverse method was used to determine the skin properties from hyperspectral images of preulcerative areas. The use of this information in lowering the false positive rate was discussed.
Electrohydrodynamic aspects of two-fluid microfluidic systems
DEFF Research Database (Denmark)
Goranovic, Goran
The goal of this thesis has been to explore fundamental theoretical principles behind micro Total Analysis Systems (µTAS), also known as lab-on-chip systems, as well as to make use of computer simulations as an evaluation technique in the process of developing and optimizing µTAS devises. This in......The goal of this thesis has been to explore fundamental theoretical principles behind micro Total Analysis Systems (µTAS), also known as lab-on-chip systems, as well as to make use of computer simulations as an evaluation technique in the process of developing and optimizing µTAS devises...... device and the cascade EO-pump, discovery of how to pump non-polar liquids by electroosmosis, theory of clogging pressures of large bubbles in microchannel contractions, and a theoretical analysis of the stability conditions for the interface between two different dielectric liquids under influence...
Electrohydrodynamic aspects of two-fluid microfluidic systems
DEFF Research Database (Denmark)
Goranovic, Goran
The goal of this thesis has been to explore fundamental theoretical principles behind micro Total Analysis Systems (µTAS), also known as lab-on-chip systems, as well as to make use of computer simulations as an evaluation technique in the process of developing and optimizing µTAS devises. This in......The goal of this thesis has been to explore fundamental theoretical principles behind micro Total Analysis Systems (µTAS), also known as lab-on-chip systems, as well as to make use of computer simulations as an evaluation technique in the process of developing and optimizing µTAS devises...... device and the cascade EO-pump, discovery of how to pump non-polar liquids by electroosmosis, theory of clogging pressures of large bubbles in microchannel contractions, and a theoretical analysis of the stability conditions for the interface between two different dielectric liquids under influence...
Explicit high-order noncanonical symplectic algorithms for ideal two-fluid systems
Xiao, Jianyuan; Morrison, Philip J; Liu, Jian; Yu, Zhi; Zhang, Ruili; He, Yang
2016-01-01
An explicit high-order noncanonical symplectic algorithm for ideal two-fluid systems is developed. The fluid is discretized as particles in the Lagrangian description, while the electromagnetic fields and internal energy are treated as discrete differential form fields on a fixed mesh. With the assistance of Whitney interpolating forms, this scheme preserves the gauge symmetry of the electromagnetic field, and the pressure field is naturally derived from the discrete internal energy. The whole system is solved using the Hamiltonian splitting method discovered by He et al., which was been successfully adopted in constructing symplectic particle-in-cell schemes. Because of its structure preserving and explicit nature, this algorithm is especially suitable for large-scale simulations for physics problems that are multi-scale and require long-term fidelity and accuracy. The algorithm is verified via two tests: studies of the dispersion relation of waves in a two-fluid plasma system and the oscillating two-stream ...
Experimental Characterization and Modelling of Energy Efficient Fluid Supply Systems
Bjorklund, Karina M; Vacca, Andrea; Opperwall, Timothy J
2015-01-01
In applications such as in agriculture, construction, and aerospace applications, high pressure hydraulics is the preferred technology to transmit mechanical power. As a consequence, the energy efficiency of the hydraulic system used to perform the mechanical actuations is of primary concern to reduce the energy consumptions in the abovementioned applications. In an hydraulic system, the primary component determining the energy efficiency is the hydraulic pump. This work focuses on the study ...
PECULIARITIES OF LAMB WAVE PROPAGATION THROUGH TWO-LAYERED THIN PLATE MATERIALS
Directory of Open Access Journals (Sweden)
A. R. Baev
2008-01-01
Full Text Available Peculiarities of the plate wave propagation through two-layered thin plate have been analyzed and formulas for velocity determination of the quickest plate mode have been proposed. The ascertained interaction makes it possible to determine coating layer thickness in accordance with the given and known elastic parameters of contacting materials. On the basis of the developed methodology experiments have been carried out that revealed qualitative and quantitative correspondence between theoretical and experimental data. The paper shows a principle possibility for assessment of material separation surface by time propagation data of the investigated mode .
Determination of homeostatic elastic moduli in two layers of the esophagus
DEFF Research Database (Denmark)
Gregersen, Hans; Liao, Donghua; Fung, Yuan Cheng
2008-01-01
for determination of incremental moduli in circumferential, axial, and cross directions in the two layers. The experiments are inflation, axial stretching, circumferential bending, and axial bending. The analysis takes advantage of knowing the esophageal zero-stress state (an open sector with an opening angle of 59......The function of the esophagus is mechanical. To understand the function, it is necessary to know how the stress and strain in the esophagus can be computed, and how to determine the stress-strain relationship of the wall materials. The present article is devoted to the issue of determining...
Solitary SH waves in two-layered traction-free plates
Djeran-Maigre, Irini; Kuznetsov, Sergey
2008-01-01
A solitary wave, resembling a soliton wave, is observed when analyzing the linear problem of polarized shear (SH) surface acoustic waves propagating in elastic orthotropic two-layered traction-free plates. The analysis is performed by applying a special complex formalism and the Modified Transfer Matrix (MTM) method. Conditions for the existence of solitary SH waves are obtained. Analytical expressions for the phase speed of the solitary wave are derived. To cite this article: I. Djeran-Maigre, S. Kuznetsov, C. R. Mecanique 336 (2008).
Numerical Modeling of an Integrated Vehicle Fluids System Loop for Pressurizing a Cryogenic Tank
LeClair, A. C.; Hedayat, A.; Majumdar, A. K.
2017-01-01
This paper presents a numerical model of the pressurization loop of the Integrated Vehicle Fluids (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance to reduce system weight and enhance reliability, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) conducted tests to verify the functioning of the IVF system using a flight-like tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to support the test program. This paper presents the simulation of three different test series, comparison of numerical prediction and test data and a novel method of presenting data in a dimensionless form. The paper also presents a methodology of implementing a compressor map in a system level code.
Majumdar, Alok K.; LeClair, Andre C.; Hedayat, Ali
2016-01-01
This paper presents a numerical model of pressurization of a cryogenic propellant tank for the Integrated Vehicle Fluid (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) has been running tests to verify the functioning of the IVF system using a flight tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to develop an integrated model of the tank and the pressurization system. This paper presents an iterative algorithm for converging the interface boundary conditions between different component models of a large system model. The model results have been compared with test data.
Working fluid concentration measurement in solar air conditioning systems
Energy Technology Data Exchange (ETDEWEB)
Romero, R.J.; Basurto-Pensado, M.A. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001. Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico); Jimenez-Heredia, A.H.; Sanchez-Mondragon, J.J. [Departamento de Optica, Instituto Nacional de Astrofisica Optica y Electronica, Luis Enrique Erro No. 1, Tonantzintla, Apartado Postal 51 y 216, C.P. 72000, Puebla (Mexico)
2006-02-15
In order to evaluate on-line corrosive electrolyte concentration in solar air conditioning systems, an optical technique to determine the concentration is being proposed. With this optical sensing method, it is possible to measure the percentage concentration of the aqueous corrosive lithium bromide solution at temperatures ranging from 25{sup o}C to 70{sup o}C and a maximum concentration of 60%. The measurement system is based on the refractive index of the solution and the data correlation, at several temperature and concentration values. The results of this work present a direct method for concentration measurement of corrosive liquids and also show the correlation among the three parameters: refractive index, temperature and weight concentration. This correlation can be used to develop the optical device for solar air conditioning systems to control and improve efficiency. (author)
Role of the Enteric Nervous System in the Fluid and Electrolyte Secretion of Rotavirus Diarrhea
Lundgren, Ove; Peregrin, Attila Timar; Persson, Kjell; Kordasti, Shirin; Uhnoo, Ingrid; Svensson, Lennart
2000-01-01
The mechanism underlying the intestinal fluid loss in rotavirus diarrhea, which often afflicts children in developing countries, is not known. One hypothesis is that the rotavirus evokes intestinal fluid and electrolyte secretion by activation of the nervous system in the intestinal wall, the enteric nervous system (ENS). Four different drugs that inhibit ENS functions were used to obtain experimental evidence for this hypothesis in mice in vitro and in vivo. The involvement of the ENS in rotavirus diarrhea indicates potential sites of action for drugs in the treatment of the disease.
Institute of Scientific and Technical Information of China (English)
Peter Mora; Yucang Wang; Fernando Alonso-Marroquin
2015-01-01
SUMMARY:Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet’s future energy demands that a key geophysical problem be solved first:how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components for micro-scale particle-based nu-merical modeling of hydraulic fracture, and fluid and heat flow in geothermal reservoirs. They are based on the latest developments of ESyS-Particle—the coupling of the lattice solid model (LSM) to simulate the nonlinear dynamics of complex solids with the lattice Boltzmann method (LBM) ap-plied to the nonlinear dynamics of coupled fluid and heat flow in the complex solid-fluid system. The coupled LSM/LBM can be used to simulate development of fracture systems in discontinuous media, elastic stress release, fluid injection and the consequent slip at joint surfaces, and hydraulic fractur-ing; heat exchange between hot rocks and water within flow pathways created through hydraulic fracturing;and fluid flow through complex, narrow, compact and gouge-or powder-filled fracture and joint systems. We demonstrate the coupled LSM/LBM to simulate the fundamental processes listed above, which are all components for the generation and sustainability of the hot-fractured rock geothermal energy fracture systems required to exploit this new green-energy resource.
DiSalvo, Roberto; Deaconu, Stelu; Majumdar, Alok
2006-01-01
One of the goals of this program was to develop the experimental and analytical/computational tools required to predict the flow of non-Newtonian fluids through the various system components of a propulsion system: pipes, valves, pumps etc. To achieve this goal we selected to augment the capabilities of NASA's Generalized Fluid System Simulation Program (GFSSP) software. GFSSP is a general-purpose computer program designed to calculate steady state and transient pressure and flow distributions in a complex fluid network. While the current version of the GFSSP code is able to handle various systems components the implicit assumption in the code is that the fluids in the system are Newtonian. To extend the capability of the code to non-Newtonian fluids, such as silica gelled fuels and oxidizers, modifications to the momentum equations of the code have been performed. We have successfully implemented in GFSSP flow equations for fluids with power law behavior. The implementation of the power law fluid behavior into the GFSSP code depends on knowledge of the two fluid coefficients, n and K. The determination of these parameters for the silica gels used in this program was performed experimentally. The n and K parameters for silica water gels were determined experimentally at CFDRC's Special Projects Laboratory, with a constant shear rate capillary viscometer. Batches of 8:1 (by weight) water-silica gel were mixed using CFDRC s 10-gallon gelled propellant mixer. Prior to testing the gel was allowed to rest in the rheometer tank for at least twelve hours to ensure that the delicate structure of the gel had sufficient time to reform. During the tests silica gel was pressure fed and discharged through stainless steel pipes ranging from 1", to 36", in length and three diameters; 0.0237", 0.032", and 0.047". The data collected in these tests included pressure at tube entrance and volumetric flowrate. From these data the uncorrected shear rate, shear stress, residence time
Wear forms of heterogeneous electro-rheological fluids working in a hydraulic clutch system
Ziabska, E.; Duchowski, J.; Olszak, A.; Osowski, K.; Kesy, A.; Kesy, Z.; Choi, S. B.
2017-09-01
The paper presents experimental results concerning the wear of heterogeneous electro-rheological (ER) fluids operating as working fluids in a complex clutch system consisting of a hydrodynamic clutch and a cylinder viscous clutch. The change of electric field intensity in the clutches results in change of sheer stress values in working fluids what causes the change of transmitted torque. This work shows that the most important factors affecting the wear of the ER fluid are the electric field of high intensity, the accompanying electrical breakdown, and the high temperature of the silicone oil. In addition, the water from the humid air absorbed mainly by hygroscopic particles influences a significant impact on the wear of the working fluid. Various forms of wear particles of the fluid depending on the prevailing conditions such as working mode are observed from the microscopic aspects. It is observed that the particles are flattened, rolled out or smashed into smaller fragments, partially melted, wrinkled and glued or caked. In addition, it is identified that the partial destruction of silicone oil is occurred due to the damage of the hydrocarbon chains, as evidenced by the decrease in its viscosity and the presence of the particle matter newly containing silicon.
[Effects of irrigation fluid absorption on system during mini-percutaneous nephrolithotomy].
Li, Jiong-Ming; Liang, Ming; Wang, Guang; Liu, Jian-He; Chen, Jian; Jiang, Yong-Ming; Zhang, Jing-Song; Jia, Wan-Jian; Zhang, Hai-Yan
2009-02-15
To determine the effects of irrigation fluid absorption on system hemodynamics, fluid-electrolyte and hormone during mini-percutaneous nephrolithotomy. In this study 128 patients with renal calculus or calculus of superior ureter from January 2007 to February 2008 were collected. Hemoglobin (Hb), hematocrit (Hct), plasma osmotic pressure (POP), fluid-electrolyte, serum creatinine (Cre), renin, angiotensin II and aldosterone were determined before and after operation. Heart rate (HR), mean arterial blood pressure (MAP) and oxygen saturation (SPO(2)) were recorded dynamically every 30 min. The HR speeded up accompanied with the irrigation time. When compared with before operation, POP, Cl(-), renin and Cre were significantly increased after operation; Hb, Hct and K(+) were significantly decreased after operation; MAP, SPO(2), Na(+), aldosterone and angiotensin II did not change significantly after operation. No serious surgery-related complication occurred in all patients. Irrigation fluid is absorbed during mini-percutaneous nephrolithotomy. The absorption amount is positively correlated with irrigation time. Changes of hemodynamics, fluid-electrolyte balance and renin may be caused by the irrigation fluid absorption.
A hybrid grid method in an auxiliary coordinate system for irregular fluid-solid interface modelling
Qu, Yingming; Huang, Jianping; Li, Zhenchun; Li, Jinli
2017-03-01
Seismic wave propagation in a fluid-solid environment cannot be simulated with a single wave equation, but can be described by use of the acoustic and viscoelastic wave equations for their respective fluid and solid parts. Proper boundary conditions at the fluid-solid interface based on the relationship between pressure and stress are crucial when combining the two different wave equations. Traditional finite difference methods have had difficulties in dealing with the irregular fluid-solid interface topography. The Cartesian grids discretization leads to artificial reflections and diffractions during the conversion between acoustic wave and elastic waves. We propose a variable coordinate transformation methodology to simulate seismic waves in a fluid-solid environment. An irregular fluid-solid interface can be transformed into a horizontal interface, so that pressure and stress can be well converted. We also introduce a multiblock coordinate transformation (MCT) method which meshes each layer with curvilinear grids to transform the interface topography into a horizontal one, thereby allocating vertical sampling points adaptively. The grid size is determined adaptively based on the shape and the parameters of the target area, which reduces in size in when the layers are thin or exhibit low velocities. A Lebedev-standard staggered grid scheme is applied to the MCT method to reduce both the computational cost associated with the Lebedev grid scheme and the instability in the auxiliary coordinate system when using a standard staggered grid scheme.
Fluid bed gasification pilot plant fuel feeding system evaluation
Energy Technology Data Exchange (ETDEWEB)
Campbell, W.A.; Fonstad, T.; Pugsley, T.; Gerspacher, R. (Univ. of Saskatchewan, Saskatoon (Canada)), Email: wac132@mail.usask.ca; Wang Zhiguo (Saskatchewan Research Council, Saskatoon (Canada)), Email: zhiguo.wang@src.sk.ca
2009-07-01
Fluidized bed gasification (FBG) is a method for thermally converting solid biomass to a gaseous product termed syngas, which can be used as fuel for heat or electricity generation. Accurate and consistent feeding of biomass fuel into biomass FBG converters is a continuing, challenge, and was the subject of experimentation at the University of Saskatchewan biomass FBG pilot plant. The 2-conveyor feeding system for this pilot plant was tested using meat and bone meal (MBM) as feedstock, by conveying the feedstock through the system, and measuring the output rate as the fuel was discharged. The relationship between average mass-flowrate (F{sub M}) and conveyor speed (S) for the complete feeding system was characterized to be F{sub M}=0.2188S-0.42 for the tests performed. Testing of the metering conveyor coupled to the injection conveyor showed that operating these conveyors at drive synchronized speeds, air pulsed into the injection hopper, and 50 slpm injection air, produced the most consistent feed output rate. Hot fluidized bed tests followed, which showed that plugging of the injection nozzle occurred as bed temperatures increased past 700C, resulting in loss of fuel flow. The pneumatic injection nozzle was subsequently removed, and the system was found to perform adequately with it absent. (orig.)
Institute of Scientific and Technical Information of China (English)
Jiebin Liu; Jifu Zhou
2016-01-01
The Kelvin–Helmholtz instability is believed to be the dominant instability mechanism for free shear flows at large Reynolds numbers. At small Reynolds numbers, a new instability mode is identified when the temporal instability of parallel viscous two fluid mixing layers is extended to current-fluid mud systems by considering a composite error function velocity profile. The new mode is caused by the large viscosity difference between the two fluids. This interfacial mode exists when the fluid mud boundary layer is sufficiently thin. Its performance is different from that of the Kelvin–Helmholtz mode. This mode has not yet been reported for interface instability problems with large viscosity contrasts. These results are essential for further stability analysis of flows relevant to the breaking up of this type of interface.
Lock-In Imaging System for Detecting Disturbances in Fluid
Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Dimarcantonio, Albert L. (Inventor)
2014-01-01
A lock-in imaging system is configured for detecting a disturbance in air. The system includes an airplane, an interferometer, and a telescopic imaging camera. The airplane includes a fuselage and a pair of wings. The airplane is configured for flight in air. The interferometer is operatively disposed on the airplane and configured for producing an interference pattern by splitting a beam of light into two beams along two paths and recombining the two beams at a junction point in a front flight path of the airplane during flight. The telescopic imaging camera is configured for capturing an image of the beams at the junction point. The telescopic imaging camera is configured for detecting the disturbance in air in an optical path, based on an index of refraction of the image, as detected at the junction point.
Cehelsky, Priscilla; Tung, Ka Kit
1987-01-01
Previous results based on low- and intermediate-order truncations of the two-layer model suggest the existence of multiple equilibria and/or multiple weather regimes for the extratropical large-scale flow. The importance of the transient waves in the synoptic scales in organizing the large-scale flow and in the maintenance of weather regimes was emphasized. The result shows that multiple equilibria/weather regimes that are present in lower-order models examined disappear when a sufficient number of modes are kept in the spectral expansion of the solution to the governing partial differential equations. Much of the chaotic behavior of the large-scale flow that is present in intermediate-order models is now found to be spurious. Physical reasons for the drastic modification are offered. A peculiarity in the formulation of most existing two-layer models is noted that also tends to exaggerate the importance of baroclinic processes and increase the degree of unpredictability of the large-scale flow.
Modelling of fast jet formation under explosion collision of two-layer alumina/copper tubes
Directory of Open Access Journals (Sweden)
I Balagansky
2017-09-01
Full Text Available Under explosion collapse of two-layer tubes with an outer layer of high-modulus ceramics and an inner layer of copper, formation of a fast and dense copper jet is plausible. We have performed a numerical simulation of the explosion collapse of a two-layer alumina/copper tube using ANSYS AUTODYN software. The simulation was performed in a 2D-axis symmetry posting on an Eulerian mesh of 3900x1200 cells. The simulation results indicate two separate stages of the tube collapse process: the nonstationary and the stationary stage. At the initial stage, a non-stationary fragmented jet is moving with the velocity of leading elements up to 30 km/s. The collapse velocity of the tube to the symmetry axis is about 2 km/s, and the pressure in the contact zone exceeds 700 GPa. During the stationary stage, a dense jet is forming with the velocity of 20 km/s. Temperature of the dense jet is about 2000 K, jet failure occurs when the value of effective plastic deformation reaches 30.
Validation of the Two-Layer Model for Correcting Clear Sky Reflectance Near Clouds
Wen, Guoyong; Marshak, Alexander; Evans, K. Frank; Vamal, Tamas
2014-01-01
A two-layer model was developed in our earlier studies to estimate the clear sky reflectance enhancement near clouds. This simple model accounts for the radiative interaction between boundary layer clouds and molecular layer above, the major contribution to the reflectance enhancement near clouds for short wavelengths. We use LES/SHDOM simulated 3D radiation fields to valid the two-layer model for reflectance enhancement at 0.47 micrometer. We find: (a) The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; and (b) The magnitude of the 2-layer modeled enhancement agree reasonably well with the "truth" with some expected underestimation. We further extend our model to include cloud-surface interaction using the Poisson model for broken clouds. We found that including cloud-surface interaction improves the correction, though it can introduced some over corrections for large cloud albedo, large cloud optical depth, large cloud fraction, large cloud aspect ratio. This over correction can be reduced by excluding scenes (10 km x 10km) with large cloud fraction for which the Poisson model is not designed for. Further research is underway to account for the contribution of cloud-aerosol radiative interaction to the enhancement.
Traffic dynamics on two-layer complex networks with limited delivering capacity
Ma, Jinlong; Han, Weizhan; Guo, Qing; Wang, Zhenyong
2016-08-01
The traffic dynamics of multi-layer networks has attracted a great deal of interest since many real networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the average delivery capacity allocation strategy is susceptible to congestion with the wildly used shortest path routing protocol on two-layer complex networks. In this paper, we introduce a delivery capacity allocation strategy into the traffic dynamics on two-layer complex networks and focus on its effect on the traffic capacity measured by the critical point Rc of phase transition from free flow to congestion. When the total nodes delivering capacity is fixed, the delivering capacity of each node in physical layer is assigned to the degree distributions of both the physical and logical layers. Simulation results show that the proposed strategy can bring much better traffic capacity than that with the average delivery capacity allocation strategy. Because of the significantly improved traffic performance, this work may be useful for optimal design of networked traffic dynamics.
Two-Layer Tight Frame Sparsifying Model for Compressed Sensing Magnetic Resonance Imaging
Peng, Xi; Dong, Pei
2016-01-01
Compressed sensing magnetic resonance imaging (CSMRI) employs image sparsity to reconstruct MR images from incoherently undersampled K-space data. Existing CSMRI approaches have exploited analysis transform, synthesis dictionary, and their variants to trigger image sparsity. Nevertheless, the accuracy, efficiency, or acceleration rate of existing CSMRI methods can still be improved due to either lack of adaptability, high complexity of the training, or insufficient sparsity promotion. To properly balance the three factors, this paper proposes a two-layer tight frame sparsifying (TRIMS) model for CSMRI by sparsifying the image with a product of a fixed tight frame and an adaptively learned tight frame. The two-layer sparsifying and adaptive learning nature of TRIMS has enabled accurate MR reconstruction from highly undersampled data with efficiency. To solve the reconstruction problem, a three-level Bregman numerical algorithm is developed. The proposed approach has been compared to three state-of-the-art methods over scanned physical phantom and in vivo MR datasets and encouraging performances have been achieved. PMID:27747226
Analysis and Control of Two-Layer Frenkel-Kontorova Model
Institute of Scientific and Technical Information of China (English)
TANG Wen-Yan; QU Zhi-Hua; GUO Yi
2011-01-01
A one-dimensional two-layer Frenkel-Kontorova model is studied.Firstly,a feedback tracking control law is given.Then,the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method.Especially,the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity.Simulations illustrate the accuracy of the derived results.Recently,the Frenkel-Kontorova (FK) model,which describes a chain of classical particles interacting with its nearest neighbors and subjected to a periodic one-site potential,has become a useful tool to study nanotribology.[1-6] There are several generalizations of the FK model that have been introduced with the hope of understanding friction dynamics at nanoscale.These models include a manylayer model with harmonic interactions,the FrenkelKontorova-Tomlinson model (FKT) and the singlelayer model with harmonic interactions.%A one-dimensional two-layer Frenkel-Kontorova model is studied. Firstly, a feedback tracking control law is given. Then, the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method. Especially, the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity. Simulations illustrate the accuracy of the derived results.
Reverse-feeding effect of epidemic by propagators in two-layered networks
Dayu, Wu; Yanping, Zhao; Muhua, Zheng; Jie, Zhou; Zonghua, Liu
2016-02-01
Epidemic spreading has been studied for a long time and is currently focused on the spreading of multiple pathogens, especially in multiplex networks. However, little attention has been paid to the case where the mutual influence between different pathogens comes from a fraction of epidemic propagators, such as bisexual people in two separated groups of heterosexual and homosexual people. We here study this topic by presenting a network model of two layers connected by impulsive links, in contrast to the persistent links in each layer. We let each layer have a distinct pathogen and their interactive infection is implemented by a fraction of propagators jumping between the corresponding pairs of nodes in the two layers. By this model we show that (i) the propagators take the key role to transmit pathogens from one layer to the other, which significantly influences the stabilized epidemics; (ii) the epidemic thresholds will be changed by the propagators; and (iii) a reverse-feeding effect can be expected when the infective rate is smaller than its threshold of isolated spreading. A theoretical analysis is presented to explain the numerical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11135001, 11375066, and 11405059) and the National Basic Key Program of China (Grant No. 2013CB834100).
NUMERICAL SIMULATION OF HEAD-CUT WITH A TWO-LAYERED BED
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Gully erosion is one of the main causes of top soil loss, land deterioration and sources of sediment deposition in streams. Headcut often occurs in the gully erosion process when erodability of the soil layers varies, and the gully cuts through a hard layer at a point. A scouring hole appears downstream of the head cut which migrates upstream due to strong erosion in the scour hole. This paper presents numerical analyses of turbulent flow and sediment transport processes of a head-cut associated with a two-layer soil stratigraphic formation. The flow in the scour hole is three-dimensional induced by the water jet from the brink of the top layer; the sediment transport model considers sediment entrainment by the impinging jet, erosion underneath the hard layer and the retreat of the brink of the hard layer. The 3D flow simulation in the scour hole and the scouring process was verified with physical model data. The two-layer head cut migration is simulated with different flow and soil parameters, the trends of the simulated results reasonably revealed contributions of these parameters to the scouring and migration process.
Effects of Hall current and radiation absorption on MHD micropolar fluid in a rotating system
Directory of Open Access Journals (Sweden)
P.V. Satya Narayana
2013-12-01
Full Text Available The objective of this paper is to study the effects of Hall current and radiation absorption on MHD free convection mass transfer flow of a micropolar fluid in a rotating frame of reference. A uniform magnetic field acts perpendicular to the porous surface in which absorbs micropolar fluid with a constant suction velocity. The entire system rotates about the axes normal to the plate with uniform angular velocity Ω. The dimensionless governing equations for this investigation are reduced to a system of linear differential equations using regular perturbation method, and equations are solved analytically. The influence of various flow parameters of the flow field has been discussed and explained graphically. The present study is of immediate interest in geophysical, cosmically fluid dynamics, medicine, biology, and all those processes which are greatly embellished by a strong magnetic field with a low density of the gas.
Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems
Wu, Zhizheng; Ben Amara, Foued
2013-01-01
Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foue...
Calculation Sheet for the Basic Design of the ATLAS Fluid System
Energy Technology Data Exchange (ETDEWEB)
Park, Hyun Sik; Moon, S. K.; Yun, B. J.; Kwon, T. S.; Choi, K. Y.; Cho, S.; Park, C. K.; Lee, S. J.; Kim, Y. S.; Song, C. H.; Baek, W. P.; Hong, S. D
2007-03-15
The basic design of an integral effect test loop for pressurized water reactors (PWRs), the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), has been carried out by Thermal-Hydraulics Safety Research Team in Korea Atomic Energy Research Institute (KAERI). The ATLAS facility has been designed to have the length scale of 1/2 and area scale of 1/144 compared with the reference plant, APR1400, and is scaled for full pressure and temperature conditions. This report includes calculation sheets for the basic design of ATLAS fluid systems, which are consisted of a reactor pressure vessel with core simulator, the primary loop piping, a pressurizer, reactor coolant pumps, steam generators, the secondary system, the safety system, the auxiliary system, and the heat loss compensation system. The present calculation sheets will be used to help understanding the basic design of the ATLAS fluid system and its based scaling methodology.
Energy Technology Data Exchange (ETDEWEB)
Morrison, P.J., E-mail: morrison@physics.utexas.edu [Department of Physics and Institute for Fusion Studies, University of Texas, Austin (United States); Vanneste, J. [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh (United Kingdom)
2016-05-15
A method, called beatification, is presented for rapidly extracting weakly nonlinear Hamiltonian systems that describe the dynamics near equilibria of systems possessing Hamiltonian form in terms of noncanonical Poisson brackets. The procedure applies to systems like fluids and plasmas in terms of Eulerian variables that have such noncanonical Poisson brackets, i.e., brackets with nonstandard and possibly degenerate form. A collection of examples of both finite and infinite dimensions is presented.
Fluids as transducers of gravity in biological systems
Lofthouse, J
2004-01-01
A qualitative model is presented, suggesting gravitational information is transduced into biological systems primarily by its effect on spatially organised membrane and cytoplasmic flows. Continuous low affinity interactions between membrane bound cytoskeletal proteins and phospholipid flows that are undergoing forced convective and shear driven flows are shown to convert this information into spatial protein patterns, and hence cell shape. As applied here to plant cells, the feedback mechanism is shown capable not only of establishing the strict nanometer scale parallelism that exists between proteins running on the inside and outside of the cell membrane, but also to predict its maintainance and the angle of fibre realignment observed during tropic responses.
Stefánsson, Andri; Barnes, Jaime D.
2016-09-01
The chlorine isotope composition of thermal fluids from Iceland were measured in order to evaluate the source of chlorine and possible chlorine isotope fractionation in geothermal systems at divergent plate boundaries. The geothermal systems studied have a wide range of reservoir temperatures from 40 to 437 °C and in-situ pH of 6.15 to 7.15. Chlorine concentrations range from 5.2 to 171 ppm and δ37 Cl values are -0.3 to + 2.1 ‰ (n = 38). The δ37 Cl values of the thermal fluids are interpreted to reflect the source of the chlorine in the fluids. Geothermal processes such as secondary mineral formation, aqueous and vapor speciation and boiling were found to have minimal effects on the δ37 Cl values. However, further work is needed on incorporation of Cl into secondary minerals and its effect on Cl isotope fractionation. Results of isotope geochemical modeling demonstrate that the range of δ37 Cl values documented in the natural thermal fluids can be explained by leaching of the basaltic rocks by meteoric source water under geothermal conditions. Magmatic gas partitioning may also contribute to the source of Cl in some cases. The range of δ37 Cl values of the fluids result mainly from the large range of δ37 Cl values observed for Icelandic basalts, which range from -0.6 to + 1.2 ‰.
Probabilistic seismic hazard assessment for the two layer fault system of Antalya (SW Turkey) area
Dipova, Nihat; Cangir, Bülent
2017-09-01
Southwest Turkey, along Mediterranean coast, is prone to large earthquakes resulting from subduction of the African plate under the Eurasian plate and shallow crustal faults. Maximum observed magnitude of subduction earthquakes is Mw = 6.5 whereas that of crustal earthquakes is Mw = 6.6. Crustal earthquakes are sourced from faults which are related with Isparta Angle and Cyprus Arc tectonic structures. The primary goal of this study is to assess seismic hazard for Antalya area (SW Turkey) using a probabilistic approach. A new earthquake catalog for Antalya area, with unified moment magnitude scale, was prepared in the scope of the study. Seismicity of the area has been evaluated by the Gutenberg-Richter recurrence relationship. For hazard computation, CRISIS2007 software was used following the standard Cornell-McGuire methodology. Attenuation model developed by Youngs et al. Seismol Res Lett 68(1):58-73, (1997) was used for deep subduction earthquakes and Chiou and Youngs Earthq Spectra 24(1):173-215, (2008) model was used for shallow crustal earthquakes. A seismic hazard map was developed for peak ground acceleration and for rock ground with a hazard level of a 10% probability of exceedance in 50 years. Results of the study show that peak ground acceleration values on bedrock change between 0.215 and 0.23 g in the center of Antalya.
CBP [TASK 12] experimental study of the concrete salstone two-layer system
Energy Technology Data Exchange (ETDEWEB)
Samson, Eric [SIMCO Technologies, Inc., Ville de QuÃ©bec, QC (Canada); Protiere, Yannick [SIMCO Technologies, Inc., Ville de QuÃ©bec, QC (Canada)
2016-11-01
This report presents the results of a study which intended to study the behavior of concrete samples placed in contact with a wasteform mixture bearing high level of sulfate in its pore solution. A setup was prepared which consisted in a wasteform poured on top of vault concrete mixes (identified as Vault 1/4 and Vault 2 mixes) cured for approximately 6 months.
Electrohydrodynamic aspects of two-fluid microfluidic systems
DEFF Research Database (Denmark)
Goranovic, Goran
device and the cascade EO-pump, discovery of how to pump non-polar liquids by electroosmosis, theory of clogging pressures of large bubbles in microchannel contractions, and a theoretical analysis of the stability conditions for the interface between two different dielectric liquids under influence...... of external electric fields. A significant effort has been devoted to the creation of a new group at MIC, the Microfluidcs Theory and Simulation Group (MIFTS). During the first year of this PhD-study, simulation of lab-on-a-chip systems was the main topic. Later, as students were attracted to the group...... the activities expanded to include the theoretical studies. At present MIFTS consists of two postdocs, four PhD students and a number of undergraduate students, under the leadership of prof. Henrik Bruus....
Internal computational fluid mechanics on supercomputers for aerospace propulsion systems
Andersen, Bernhard H.; Benson, Thomas J.
1987-01-01
The accurate calculation of three-dimensional internal flowfields for application towards aerospace propulsion systems requires computational resources available only on supercomputers. A survey is presented of three-dimensional calculations of hypersonic, transonic, and subsonic internal flowfields conducted at the Lewis Research Center. A steady state Parabolized Navier-Stokes (PNS) solution of flow in a Mach 5.0, mixed compression inlet, a Navier-Stokes solution of flow in the vicinity of a terminal shock, and a PNS solution of flow in a diffusing S-bend with vortex generators are presented and discussed. All of these calculations were performed on either the NAS Cray-2 or the Lewis Research Center Cray XMP.
Romera, M.; Lacoste, B.; Ebels, U.; Buda-Prejbeanu, L. D.
2016-09-01
The general concepts of spin wave theory are adapted to the spin torque driven dynamics of a self-polarized system based on two layers coupled via interlayer exchange (conservative coupling) and mutual spin torque (dissipative coupling). An analytical description of the nonlinear dynamics is proposed and validated through numerical simulations. In contrast to the single layer model, the phase equation of the coupled system has a contribution coming from the dissipative part of the LLGS equation. It is shown that this is a major contribution to the frequency mandatory to describe well the most basic features of the dynamics of this coupled system. Using the proposed model a specific feature of coupled dynamics is addressed: the redshift to blueshift transition observed in the frequency current dependence of this kind of exchange coupled systems upon increasing the applied field. It is found that the blueshift regime can only occur in a region of field where the two linear eigenmodes contribute equally to the steady state mode (i.e., high mode hybridization). Finally, a general perturbed Hamiltonian equation for the coupled system is proposed.
Physics-based analysis of the hydrodynamic stress in a fluid-particle system
Zhang, Quan; Prosperetti, Andrea
2010-01-01
The paper begins by showing how standard results on the average hydrodynamic stress in a uniform fluid-particle system follow from a direct, elementary application of Cauchy’s stress principle. The same principle applied to the angular momentum balance proves the emergence, at the mesoscale, of an a
Modelling dynamic liquid-gas systems: Extensions to the volume-of-fluid solver
CSIR Research Space (South Africa)
Heyns, Johan A
2013-06-01
Full Text Available This study presents the extension of the volume-of-fluid solver, interFoam, for improved accuracy and efficiency when modelling dynamic liquid-gas systems. Examples of these include the transportation of liquids, such as in the case of fuel carried...
Local well-posedness of lower regularity solutions for the incompressible viscoelastic fluid system
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In the present paper,the local well-posedness of the incompressible viscoelastic fluid system in the whole space is proved under the following assumption on the initial data:the deformation tensor is Hlder continuous and the velocity is Lp integrable,p>d,where d is the space dimension.
Computer Software for Design, Analysis and Control of Fluid Power Systems
DEFF Research Database (Denmark)
Conrad, Finn; Sørensen, Torben; Grahl-Madsen, Mads
1999-01-01
This Deliverable presents contributions from SWING's Task 2.3 Analysis of available software solutions. The Deliverable has focus on the results from this analysis having in mind the task objectives·to carry out a thorough analysis of the state-of the-art solutions for fluid power systems modelling...
Tomo, Tadashi; Shinoda, Tosiho
2009-01-01
The central dialysis fluid delivery system (CDDS) has been mainly used for hemodialysis therapy in Japan. Validation and a parametric method are necessary for the quality control of dialysis fluid in CDDS. Validation is a concept for the assurance of system compatibility and product quality, and is defined as follows: the manufacturing and quality control methods including the system design and equipment of the manufacturing facility, manufacturing procedure and processes. Confirmed results must be kept within acceptable limits and they must be documented in a record. Important parameters for validating CDDS include: (1) setting the sterilized area; (2) decision of sterilization level; (3) confirmation of the maximum bio-burden; (4) performance of endotoxin retentive filter and reverse osmosis (RO) module, and (5) checkpoints of purity of dialysis water in the system. Taking the concept of validation and a parametric method in the management of CDDS into consideration enables the supply the purified dialysis fluid or the online prepared substitution fluid that meet the 2008 standards of the Japanese Society for Dialysis Therapy.
Experiences of Using MATLAB/Simulink in Simulation and Control of Fluid Power Systems
DEFF Research Database (Denmark)
Zhou, Jianjun; Conrad, Finn; Sørensen, Torben
1999-01-01
MATLAB and Simulink are widely used as primary software tools in teaching and research around the word. This paper presents our experiences of using MATLAB/Simulink in simulation and control of fluid power systems. The application concerned mainly in this paper is a hydraulic test robot, shown...
Experiences of Using MATLAB/Simulink in Simulation and Control of Fluid Power Systems
DEFF Research Database (Denmark)
Zhou, Jianjun; Conrad, Finn; Sørensen, Torben
1999-01-01
MATLAB and Simulink are widely used as primary software tools in teaching and research around the word. This paper presents our experiences of using MATLAB/Simulink in simulation and control of fluid power systems. The application concerned mainly in this paper is a hydraulic test robot, shown...
A deep crustal fluid channel into the San Andreas Fault system near Parkfield, California
Becken, M.; Ritter, O.; Park, S.K.; Bedrosian, P.A.; Weckmann, U.; Weber, M.
2008-01-01
Magnetotelluric (MT) data from 66 sites along a 45-km-long profile across the San Andreas Fault (SAF) were inverted to obtain the 2-D electrical resistivity structure of the crust near the San Andreas Fault Observatory at Depth (SAFOD). The most intriguing feature of the resistivity model is a steeply dipping upper crustal high-conductivity zone flanking the seismically defined SAF to the NE, that widens into the lower crust and appears to be connected to a broad conductivity anomaly in the upper mantle. Hypothesis tests of the inversion model suggest that upper and lower crustal and upper-mantle anomalies may be interconnected. We speculate that the high conductivities are caused by fluids and may represent a deep-rooted channel for crustal and/or mantle fluid ascent. Based on the chemical analysis of well waters, it was previously suggested that fluids can enter the brittle regime of the SAF system from the lower crust and mantle. At high pressures, these fluids can contribute to fault-weakening at seismogenic depths. These geochemical studies predicted the existence of a deep fluid source and a permeable pathway through the crust. Our resistivity model images a conductive pathway, which penetrates the entire crust, in agreement with the geochemical interpretation. However, the resistivity model also shows that the upper crustal branch of the high-conductivity zone is located NE of the seismically defined SAF, suggesting that the SAF does not itself act as a major fluid pathway. This interpretation is supported by both, the location of the upper crustal high-conductivity zone and recent studies within the SAFOD main hole, which indicate that pore pressures within the core of the SAF zone are not anomalously high, that mantle-derived fluids are minor constituents to the fault-zone fluid composition and that both the volume of mantle fluids and the fluid pressure increase to the NE of the SAF. We further infer from the MT model that the resistive Salinian block
A report to the Department of Energy on studies of complexity in fluid systems
Energy Technology Data Exchange (ETDEWEB)
Constantin, P.; Dupont, T.F.; Kadanoff, L.P.; Nagel, S.
1994-01-14
The objective of this project is to bring together researchers from several disciplines who share an interest in studying the development of complexity in fluid systems. The researchers involved have expertise in mathematics, numerical computation, and theoretical and experimental physics. There are three main subjects: the mathematical and phenomenological approaches to turbulence; the development of singularities in fluid flow, most particularly in the motion of interfaces also mathematical and numerical studies of viscous droplet generation; and studies of the scaling properties of highly viscous liquids and the nature of avalanche dynamics in granular flows.
Institute of Scientific and Technical Information of China (English)
SHU BiFen; SHEN Hui; CHEN MeiYuan; XIA JianHan; WANG Xiang; SUN JianWei
2008-01-01
In this study, experiments are carried out on the effects of magnetic fluids on the crystallization char- acterizations in a multi-component and multiphase system, which contains the liquid and the vapor of HCFC141b, water, water vapor, and gas hydrates. The mass transfer phenomena between the phase interfaces of water-HCFC141b and water-vapor are also researched. The experimental results show that in the presence of a rotary magnetic field, magnetic fluids can remarkably enhance the heat and mass transfer between phase interfaces and, therefore, improve the performance of crystallization, especially in improving the formation temperature and velocity.
Behrooz, Majid; Gordaninejad, Faramarz
2016-09-01
This paper presents a three-dimensional study of a controllable flexible magnetically-activated micropump. The tubular micropump employs magnetically induced deformation of magnetorheological elastomer and one-way flexible conical valves for fluid transport. Three-dimensional magneto-fluid-solid interaction analysis is employed to investigate the performance of the system. The effects of key material, geometric, and magnetic parameters on the effectiveness of the system are examined. It is demonstrated that the proposed system can propel the fluid unidirectionally, and the volume of the transported fluid is significantly affected by some of the design parameters.
System and technique for characterizing fluids using ultrasonic diffraction grating spectroscopy
Greenwood, Margaret S.
2008-07-08
A system for determining property of multiphase fluids based on ultrasonic diffraction grating spectroscopy includes a diffraction grating on a solid in contact with the fluid. An interrogation device delivers ultrasound through the solid and a captures a reflection spectrum from the diffraction grating. The reflection spectrum exhibits peaks whose relative size depends on the properties of the various phases of the multiphase fluid. For example, for particles in a liquid, the peaks exhibit dependence on the particle size and the particle volume fraction. Where the exact relationship is know know a priori, data from different peaks of the same reflection spectrum or data from the peaks of different spectra obtained from different diffraction gratings can be used to resolve the size and volume fraction.
[Cerebrospinal fluid sorption in the system of complex treatment of chronic cerebral ischemia].
Shulëv, Iu A; Starchenko, A A; Bikmullin, V N; Dorosh, K V; Martynov, B V
1997-01-01
The cerebrospinal fluid was investigated in 16 patients with chronic cerebral ischemia. Reactions of the local immune system of the liquor was shown to change by the autoimmune type. Medical efficiency of cerebrospinal fluid sorption was proved and it can be considered a method of detoxication aimed at breaking the pathogenetic chain: formation of abundance of the autoantibodies--increased amount of the circulating immunocomplexes--damage of the cell membranes--discharge of deep antigens--appearance of a new generation of autoantibodies. Using cerebrospinal fluid sorption as a test for the detection of latent functional reserves of the neurons not changed irreversibly in the zone of reduced perfusion of the cerebral tissue is thought to be a perspective method.
Khalil, Mohammed S; Kurniawan, Fajri; Khan, Muhammad Khurram; Alginahi, Yasser M
2014-01-01
This paper presents a novel watermarking method to facilitate the authentication and detection of the image forgery on the Quran images. Two layers of embedding scheme on wavelet and spatial domain are introduced to enhance the sensitivity of fragile watermarking and defend the attacks. Discrete wavelet transforms are applied to decompose the host image into wavelet prior to embedding the watermark in the wavelet domain. The watermarked wavelet coefficient is inverted back to spatial domain then the least significant bits is utilized to hide another watermark. A chaotic map is utilized to blur the watermark to make it secure against the local attack. The proposed method allows high watermark payloads, while preserving good image quality. Experiment results confirm that the proposed methods are fragile and have superior tampering detection even though the tampered area is very small.
Transient response of a vertical electric dipole (VED) on a two-layer medium
Poh, S. Y.; Kong, J. A.
The transient electromagnetic radiation by a vertical electric dipole on a two-layer medium is analyzed using the double deformation technique, which is a modal technique based on identification of singularities in the complex frequency and wavenumber planes. Previous application of the double deformation technique to the solution of this problem is incomplete in the early time response. In this paper it is shown that the existence of a pole locus on the negative imaginary frequency axis, which dominates the early time response, proves crucial in obtaining the solution for all times. A variety of combinations of parameters are used to illustrate the double deformation technique, and results will be compared with those obtained via explicit inversion, and a single deformation method.
STRESS ANALYSIS AND BURST PRESSURE DETERMINATION OF TWO LAYER COMPOUND PRESSURE VESSEL
Directory of Open Access Journals (Sweden)
HARERAM LOHAR
2013-02-01
Full Text Available Multilayer pressure vessel is designed to work under high-pressure condition. This paper introduces the stress analysis and the burst pressure calculation of a two-layer shrink fitted pressure vessel. In the shrink-fitting problems, considering long hollow cylinders, the plane strain hypothesis can be regarded as more natural. Generally hoops stress distribution is non-linear and sharply reduced toward the outer surface. By shrink fitting concentric shells towards the inner shells are placed in residual compression so that the initial compressive hoop stress must be relieved by internal pressure before hoop tensile stress are developed. Therefore the maximum hoop stress will be reduced, resulting more burst pressure. The analytical results of stress distribution and burst pressure is calculated and validated by ANSYS Workbench results.
Testing the Two-Layer Model for Correcting Clear Sky Reflectance near Clouds
Wen, Guoyong; Marshak, Alexander; Evans, Frank; Varnai, Tamas; Levy, Rob
2015-01-01
A two-layer model (2LM) was developed in our earlier studies to estimate the clear sky reflectance enhancement due to cloud-molecular radiative interaction at MODIS at 0.47 micrometers. Recently, we extended the model to include cloud-surface and cloud-aerosol radiative interactions. We use the LES/SHDOM simulated 3D true radiation fields to test the 2LM for reflectance enhancement at 0.47 micrometers. We find: The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; the cloud-molecular interaction alone accounts for 70 percent of the enhancement; the cloud-surface interaction accounts for 16 percent of the enhancement; the cloud-aerosol interaction accounts for an additional 13 percent of the enhancement. We conclude that the 2LM is simple to apply and unbiased.
Study of electronic and optical properties of two-layered hydrogenated aluminum nitrate nanosheet
Faghihzadeh, Somayeh; Shahtahmasebi, Nasser; Rezaee Roknabadi, Mahmood
2017-09-01
First principle calculations based on density functional theory using GW approximation and two particle Bethe-Salpeter equation with electron-hole effect were performed to investigate electronic structure and optical properties of two-layered hydrogenated AlN. According to many body green function due to decrease in dimension and considering electron-electron effect, direct (indirect) band gap change from 2 (1.01) eV to 4.83 (3.62) eV. The first peak in imaginary part of dielectric function was observed in parallel direction to a plane obtaining 3.4 was achieved by bound exciton states possess 1.39 eV. The first absorption peak was seen in two parallel and perpendicular directions to a plane which are in UV region.
Initial stresses in two-layer metal domes due to imperfections of their production and assemblage
Directory of Open Access Journals (Sweden)
Lebed Evgeniy Vasil’evich
2015-04-01
Full Text Available The process of construction of two-layer metal domes is analyzed to illustrate the causes of initial stresses in the bars of their frames. It has been noticed that it is impossible to build such structures with ideal geometric parameters because of imperfections caused by objective reasons. These imperfections cause difficulties in the process of connection of the elements in the joints. The paper demonstrates the necessity of fitting operations during assemblage that involve force fitting and yield initial stresses due to imperfections. The authors propose a special method of computer modeling of enforced elimination of possible imperfections caused by assemblage process and further confirm the method by an analysis of a concrete metal dome.
INFLUENCE OF TEMPERATURE ON BEHAVIOR OF THE INTERFACIAL CRACK BETWEEN THE TWO LAYERS
Directory of Open Access Journals (Sweden)
Jelena M Djoković
2010-01-01
Full Text Available In this paper is considered a problem of the semi-infinite crack at the interface between the two elastic isotropic layers in conditions of the environmental temperature change. The energy release rate needed for the crack growth along the interface was determined, for the case when the two-layered sample is cooled from the temperature of the layers joining down to the room temperature. It was noticed that the energy release rate increases with the temperature difference increase. In the paper is also presented the distribution of stresses in layers as a function of the temperature and the layers' thickness variations. Analysis is limited to the case when the bimaterial sample is exposed to uniform temperature.
The fuzzy coat of pathological human Tau fibrils is a two-layered polyelectrolyte brush.
Wegmann, Susanne; Medalsy, Izhar D; Mandelkow, Eckhard; Müller, Daniel J
2013-01-22
The structure and properties of amyloid-like Tau fibrils accumulating in neurodegenerative diseases have been debated for decades. Although the core of Tau fibrils assembles from short β-strands, the properties of the much longer unstructured Tau domains protruding from the fibril core remain largely obscure. Applying immunogold transmission EM, and force-volume atomic force microscopy (AFM), we imaged human Tau fibrils at high resolution and simultaneously mapped their mechanical and adhesive properties. Tau fibrils showed a ≈ 16-nm-thick fuzzy coat that resembles a two-layered polyelectrolyte brush, which is formed by the unstructured short C-terminal and long N-terminal Tau domains. The mechanical and adhesive properties of the fuzzy coat are modulated by electrolytes and pH, and thus by the cellular environment. These unique properties of the fuzzy coat help in understanding how Tau fibrils disturb cellular interactions and accumulate in neurofibrillary tangles.
Sparse/DCT (S/DCT) two-layered representation of prediction residuals for video coding.
Kang, Je-Won; Gabbouj, Moncef; Kuo, C-C Jay
2013-07-01
In this paper, we propose a cascaded sparse/DCT (S/DCT) two-layer representation of prediction residuals, and implement this idea on top of the state-of-the-art high efficiency video coding (HEVC) standard. First, a dictionary is adaptively trained to contain featured patterns of residual signals so that a high portion of energy in a structured residual can be efficiently coded via sparse coding. It is observed that the sparse representation alone is less effective in the R-D performance due to the side information overhead at higher bit rates. To overcome this problem, the DCT representation is cascaded at the second stage. It is applied to the remaining signal to improve coding efficiency. The two representations successfully complement each other. It is demonstrated by experimental results that the proposed algorithm outperforms the HEVC reference codec HM5.0 in the Common Test Condition.
Development of an algebraic stress/two-layer model for calculating thrust chamber flow fields
Chen, C. P.; Shang, H. M.; Huang, J.
1993-01-01
Following the consensus of a workshop in Turbulence Modeling for Liquid Rocket Thrust Chambers, the current effort was undertaken to study the effects of second-order closure on the predictions of thermochemical flow fields. To reduce the instability and computational intensity of the full second-order Reynolds Stress Model, an Algebraic Stress Model (ASM) coupled with a two-layer near wall treatment was developed. Various test problems, including the compressible boundary layer with adiabatic and cooled walls, recirculating flows, swirling flows and the entire SSME nozzle flow were studied to assess the performance of the current model. Detailed calculations for the SSME exit wall flow around the nozzle manifold were executed. As to the overall flow predictions, the ASM removes another assumption for appropriate comparison with experimental data, to account for the non-isotropic turbulence effects.
Cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate
Institute of Scientific and Technical Information of China (English)
Xiang Yan-Xun; Deng Ming-Xi
2008-01-01
The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of acoustic waves at an interface.In general,the cumulative second-harmonic generation of a dispersive guided wave propagation does not occur.However,the present paper shows that the second-harmonic of Lamb wave propagation arising from the nonlinear interaction of the partial bulk acoustic waves and the restriction of the three boundaries of the solid plates does have a cumulative growth effect if some conditions are satisfied.Through boundary condition and initial condition of excitation,the analytical expression of cumulative second-harmonic of Lamb waves propagation is determined.Numerical results show the cumulative effect of Lamb waves on second-harmonic field patterns.
Calculation of AC loss in two-layer superconducting cable with equal currents in the layers
Erdogan, Muzaffer
2016-12-01
A new method for calculating AC loss of two-layer SC power transmission cables using the commercial software Comsol Multiphysics, relying on the approach of the equal partition of current between the layers is proposed. Applying the method to calculate the AC-loss in a cable composed of two coaxial cylindrical SC tubes, the results are in good agreement with the analytical ones of duoblock model. Applying the method to calculate the AC-losses of a cable composed of a cylindrical copper former, surrounded by two coaxial cylindrical layers of superconducting tapes embedded in an insulating medium with tape-on-tape and tape-on-gap configurations are compared. A good agreement between the duoblock model and the numerical results for the tape-on-gap cable is observed.
2-DE combined with two-layer feature selection accurately establishes the origin of oolong tea.
Chien, Han-Ju; Chu, Yen-Wei; Chen, Chi-Wei; Juang, Yu-Min; Chien, Min-Wei; Liu, Chih-Wei; Wu, Chia-Chang; Tzen, Jason T C; Lai, Chien-Chen
2016-11-15
Taiwan is known for its high quality oolong tea. Because of high consumer demand, some tea manufactures mix lower quality leaves with genuine Taiwan oolong tea in order to increase profits. Robust scientific methods are, therefore, needed to verify the origin and quality of tea leaves. In this study, we investigated whether two-dimensional gel electrophoresis (2-DE) and nanoscale liquid chromatography/tandem mass spectroscopy (nano-LC/MS/MS) coupled with a two-layer feature selection mechanism comprising information gain attribute evaluation (IGAE) and support vector machine feature selection (SVM-FS) are useful in identifying characteristic proteins that can be used as markers of the original source of oolong tea. Samples in this study included oolong tea leaves from 23 different sources. We found that our method had an accuracy of 95.5% in correctly identifying the origin of the leaves. Overall, our method is a novel approach for determining the origin of oolong tea leaves.
A TWO-LAYER RECURRENT NEURAL NETWORK BASED APPROACH FOR OVERLAY MULTICAST
Institute of Scientific and Technical Information of China (English)
Liu Shidong; Zhang Shunyi; Zhou Jinquan; Qiu Gong'an
2008-01-01
Overlay multicast has become one of the most promising multicast solutions for IP network, and Neutral Network(NN) has been a good candidate for searching optimal solutions to the constrained shortest routing path in virtue of its powerful capacity for parallel computation. Though traditional Hopfield NN can tackle the optimization problem, it is incapable of dealing with large scale networks due to the large number of neurons. In this paper, a neural network for overlay multicast tree computation is presented to reliably implement routing algorithm in real time. The neural network is constructed as a two-layer recurrent architecture, which is comprised of Independent Variable Neurons (IDVN) and Dependent Variable Neurons (DVN), according to the independence of the decision variables associated with the edges in directed graph. Compared with the heuristic routing algorithms, it is characterized as shorter computational time, fewer neurons, and better precision.
Arciniega-Ceballos, A.; Spina, L.; Scheu, B.; Dingwell, D. B.
2015-12-01
We have investigated the dynamics of Newtonian fluids with viscosities (10-1000 Pa s; corresponding to mafic to intermediate silicate melts) during slow decompression, in a Plexiglas shock tube. As an analogue fluid we used silicon oil saturated with Argon gas for 72 hours. Slow decompression, dropping from 10 MPa to ambient pressure, acts as the excitation mechanism, initiating several processes with their own distinct timescales. The evolution of this multi-timescale phenomenon generates complex non-stationary microseismic signals, which have been recorded with 7 high-dynamic piezoelectric sensors located along the conduit. Correlation analysis of these time series with the associated high-speed imaging enables characterization of distinct phases of the dynamics of these viscous fluids and the extraction of the time and the frequency characteristics of the individual processes. We have identified fluid-solid elastic interaction, degassing, fluid mass expansion and flow, bubble nucleation, growth, coalescence and collapse, foam building and vertical wagging. All these processes (in fine and coarse scales) are sequentially coupled in time, occur within specific pressure intervals, and exhibit a localized distribution in space. Their coexistence and interactions constitute the stress field and driving forces that determine the dynamics of the system. Our observations point to the great potential of this experimental approach in the understanding of volcanic processes and volcanic seismicity.
Lee, Seung-Hoon; Shin, Muncheol; Hwang, Seongpil; Jang, Jae-Won
2015-12-18
Previous research has shown that disorder, dislocation, and carrier concentration are the main factors impacting transitions in the traditional metal-insulator transition (MIT) and metal-semiconductor transition (MST). In this study, it is demonstrated that a non-traditional metal-semiconductor transition governed by two-layer conduction is possible by tuning the conducting channel of one layer of the two-layer conduction system. By means of the electroless deposition method we produced Au nanofeatures (AuNFs) on p-type silicon (p-Si) as the two-layer conduction system, controlling AuNF coverage (Au%) below and above the percolation threshold (p c). Even when the AuNF coverage percentage is larger than p c, the resistivities of the AuNFs on p-Si show MST as the temperature increases. To demonstrate this finding, we present a conduction model based upon two predominant parallel conductions by AuNFs and p-Si in the present paper. In the results, we show how the temperature of the MST (T MST) is tuned from 145 to 232 K as Au% is changed from 82.7 to 54.3%.
Artery buckling analysis using a two-layered wall model with collagen dispersion.
Mottahedi, Mohammad; Han, Hai-Chao
2016-07-01
Artery buckling has been proposed as a possible cause for artery tortuosity associated with various vascular diseases. Since microstructure of arterial wall changes with aging and diseases, it is essential to establish the relationship between microscopic wall structure and artery buckling behavior. The objective of this study was to developed arterial buckling equations to incorporate the two-layered wall structure with dispersed collagen fiber distribution. Seven porcine carotid arteries were tested for buckling to determine their critical buckling pressures at different axial stretch ratios. The mechanical properties of these intact arteries and their intima-media layer were determined via pressurized inflation test. Collagen alignment was measured from histological sections and modeled by a modified von-Mises distribution. Buckling equations were developed accordingly using microstructure-motivated strain energy function. Our results demonstrated that collagen fibers disperse around two mean orientations symmetrically to the circumferential direction (39.02°±3.04°) in the adventitia layer; while aligning closely in the circumferential direction (2.06°±3.88°) in the media layer. The microstructure based two-layered model with collagen fiber dispersion described the buckling behavior of arteries well with the model predicted critical pressures match well with the experimental measurement. Parametric studies showed that with increasing fiber dispersion parameter, the predicted critical buckling pressure increases. These results validate the microstructure-based model equations for artery buckling and set a base for further studies to predict the stability of arteries due to microstructural changes associated with vascular diseases and aging.
Dynamic behavior of valve system in linear compressor based on fluid-structure interaction
Energy Technology Data Exchange (ETDEWEB)
Choi, Yong Sik; Lee, Jun Ho; Jeong, Weui Bong [Pusal National University, Busan (Korea, Republic of); Kim, Il Geun [Locus Company Limited, Busan (Korea, Republic of)
2010-07-15
In refrigerator designs, the linear compressor is preferable to the recipro-type compressor, due to its higher energy efficiency. The linear compressor's valve system, however, causes significant noise, not only in the steady state but also in the transient state. To accurately predict the behavior of the suction and discharge valve system in both states, the interaction between the fluid flowing through the valves and the structural deformation of the valves needs to be understood. In the present study, the steady-state behaviors of the valve system were numerically analyzed using ADINA software, which takes fluid-structure interaction (FSI) into account. This computational analysis thereafter was experimentally validated. The effects of a pre-load of the conical compression spring on the dynamic characteristics of the valve system also were analyzed
Fluid Dynamics Assessment of the VPCAR Water Recovery System in Partial and Microgravity
Niederhaus, Charles; Nahra, Henry; Flynn, Michael
2006-01-01
The Vapor Phase Catalytic Ammonia Removal (VPCAR) system is being developed to recycle water for future NASA Exploration Missions. Testing was recently conducted on NASA s C-9B Reduced Gravity Aircraft to determine the microgravity performance of a key component of the VPCAR water recovery system. Six flights were conducted to evaluate the fluid dynamics of the Wiped-Film Rotating Disk (WFRD) distillation component of the VPCAR system in microgravity, focusing on the water delivery method. The experiments utilized a simplified system to study the process of forming a thin film on a disk similar to that in the evaporator section of VPCAR. Fluid issues are present with the current configuration, and the initial alternative configurations were only partial successful in microgravity operation. The underlying causes of these issues are understood, and new alternatives are being designed to rectify the problems.
Virtual Community Life Cycle: a Model to Develop Systems with Fluid Requirements
El Morr, Christo; Maret, Pierre de; Rioux, Marcia; Dinca-Panaitescu, Mihaela; Subercaze, Julien
2011-01-01
This paper reports the results of an investigation into the life cycle model needed to develop information systems for group of people with fluid requirements. For this purpose, we developed a modified spiral model and applied to the analysis, design and implementation of a virtual community for a group of researchers and organizations that collaborated in a research project and had changing system requirements? The virtual knowledge community was dedicated to support mobilization and dissemi...
Ownens, Albert K.; Lavelle, Thomas M.; Hervol, David S.
2010-01-01
A Dual Brayton Power Conversion System (DBPCS) has been tested at the NASA Glenn Research Center using Nitrogen (N2) as the working fluid. This system uses two closed Brayton cycle systems that share a common heat source and working fluid but are otherwise independent. This system has been modeled using the Numerical Propulsion System Simulation (NPSS) environment. This paper presents the results of a numerical study that investigated system performance changes resulting when the working fluid is changed from gaseous (N2) to gaseous carbon dioxide (CO2).
McClure, James E.; Berrill, Mark A.; Gray, William G.; Miller, Cass T.
2016-09-01
Multiphase flows in porous medium systems are typically modeled at the macroscale by applying the principles of continuum mechanics to develop models that describe the behavior of averaged quantities, such as fluid pressure and saturation. These models require closure relations to produce solvable forms. One of these required closure relations is an expression relating the capillary pressure to fluid saturation and, in some cases, other topological invariants such as interfacial area and the Euler characteristic (or average Gaussian curvature). The forms that are used in traditional models, which typically consider only the relationship between capillary pressure and saturation, are hysteretic. An unresolved question is whether the inclusion of additional morphological and topological measures can lead to a nonhysteretic closure relation. Relying on the lattice Boltzmann (LB) method, we develop an approach to investigate equilibrium states for a two-fluid-phase porous medium system, which includes disconnected nonwetting phase features. A set of simulations are performed within a random close pack of 1964 spheres to produce a total of 42 908 distinct equilibrium configurations. This information is evaluated using generalized additive models to quantitatively assess the degree to which functional relationships can explain the behavior of the equilibrium data. The variance of various model estimates is computed, and we conclude that, except for the limiting behavior close to a single fluid regime, capillary pressure can be expressed as a deterministic and nonhysteretic function of fluid saturation, interfacial area between the fluid phases, and the Euler characteristic. To our knowledge, this work is unique in the methods employed, the size of the data set, the resolution in space and time, the true equilibrium nature of the data, the parametrizations investigated, and the broad set of functions examined. The conclusion of essentially nonhysteretic behavior provides
Couple-Stress Fluid Improves Dynamic Response of Gear-Pair System Supported by Journal Bearings
Directory of Open Access Journals (Sweden)
Cai-Wan Chang-Jian
2012-01-01
Full Text Available A systematic analysis of the dynamic behavior of a gear-bearing system with nonlinear suspension, couple-stress fluid flow effect, nonlinear oil-film force, and nonlinear gear mesh force is performed in the present study. The dynamic orbits of the system are observed using bifurcation diagrams plotted using the dimensionless rotational speed ratio as a control parameter. The onset of chaotic motion is identified from the phase diagrams, power spectra, Poincaré maps, Lyapunov exponents and fractal dimension of the gear-bearing system. The numerical results reveal that the system exhibits a diverse range of periodic, subharmonic, quasiperiodic, and chaotic behaviors. The couple-stress fluid would be a useful lubricating fluid to suppress nonlinear dynamic responses and improve the steady of the systems. The results presented in this study provide some useful insights into the design and development of a gear-bearing system for rotating machinery that operates in highly rotational speed and highly nonlinear regimes.
Establishment of optimized ELISA system specific for HLA-G in body fluids.
Ouji-Sageshima, N; Geraghty, D E; Ishitani, A; Hatake, K; Ito, T
2016-12-01
Recently, human leukocyte antigen-G (HLA-G) has been a focus in the field of reproductive immunology, tumor progression and transplantation, because of its inhibitory function as ligand to the inhibitory receptors leukocyte immunoglobulin-like receptors (LILR) B1 and LILRB2. The HLA-G is expressed in distinct mRNA isoforms, one of which encodes a soluble HLA-G (sHLA-G) protein, detectable by sandwich ELISA. Therefore, sHLA-G ELISAs have been used as a noninvasive diagnosis system. While a number of sHLA-G-specific ELISAs have been described, our prior studies showed that data obtained by the conventional ELISA system detecting sHLA-G in body fluids was not consistent with the data obtained from immunoprecipitation (IP)/immunoblotting (IB). Therefore, we established an optimized ELISA system described in this report, which yields results consistent with IP/IB analysis. Using this system, we determined sHLA-G protein in amniotic fluids, and found that sHLA-G levels at preterm (∼36 weeks) were clearly higher than those at term (37-41 weeks). These data and supporting experiments showed that the ELISA system we established can be an useful tools for the detection of sHLA-G protein in body fluids than the conventional ELISA system.
Yilbas, Bekir Sami; Kumar, Aditya; Bhushan, Bharat
2014-01-01
Single- and two-layer coatings were deposited onto carbon steel using a high-velocity oxy-fuel deposition gun. The two-layer coating consisted of a top layer of tungsten carbide cobalt/nickel alloy blend that provides wear resistance and a bottom layer of iron/molybdenum blend that provides corrosion resistance. The morphological changes in the single- and two-layer coatings were examined using scanning electron microscopy. The residual stresses formed on the surface of various coatings were determined from x-ray diffraction data. Nanomechanical properties were measured using the nanoindentation technique. Microhardness and fracture toughness were measured incorporating the microindentation tests. Macrowear and macrofriction characteristics were measured using the pin-on-disk testing apparatus. The goal of this study was to ensure that the mechanical properties, friction, and wear resistance of the two-layer coating are similar to that of the single-layer coating.
Larson, John Philip
Smart material electro-hydraulic actuators (EHAs) utilize fluid rectification via one-way check valves to amplify the small, high-frequency vibrations of certain smart materials into large motions of a hydraulic cylinder. Although the concept has been demonstrated in previously, the operating frequency of smart material EHA systems has been limited to a small fraction of the available bandwidth of the driver materials. The focus of this work is to characterize and model the mechanical performance of a magnetostrictive EHA considering key system components: rectification valves, smart material driver, and fluid-system components, leading to an improved actuator design relative to prior work. The one-way valves were modeled using 3-D finite element analysis, and their behavior was characterized experimentally by static and dynamic experimental measurement. Taking into account the effect of the fluid and mechanical conditions applied to the valves within the pump, the dynamic response of the valve was quantified and applied to determine rectification bandwidth of different valve configurations. A novel miniature reed valve, designed for a frequency response above 10~kHz, was fabricated and tested within a magnetostrictive EHA. The nonlinear response of the magnetostrictive driver, including saturation and hysteresis effects, was modeled using the Jiles-Atherton approach to calculate the magnetization and the resulting magnetostriction based on the applied field calculated within the rod from Maxwell's equations. The dynamic pressure response of the fluid system components (pumping chamber, hydraulic cylinder, and connecting passages) was measured over a range of input frequencies. For the magnetostrictive EHA tested, the peak performance frequency was found to be limited by the fluid resonances within the system. A lumped-parameter modeling approach was applied to model the overall behavior of a magnetostrictive EHA, incorporating models for the reed valve response
Fluid pressure responses for a Devil's Slide-like system: problem formulation and simulation
Thomas, Matthew A.; Loague, Keith; Voss, Clifford I.
2015-01-01
This study employs a hydrogeologic simulation approach to investigate subsurface fluid pressures for a landslide-prone section of the central California, USA, coast known as Devil's Slide. Understanding the relative changes in subsurface fluid pressures is important for systems, such as Devil's Slide, where slope creep can be interrupted by episodic slip events. Surface mapping, exploratory core, tunnel excavation records, and dip meter data were leveraged to conceptualize the parameter space for three-dimensional (3D) Devil's Slide-like simulations. Field observations (i.e. seepage meter, water retention, and infiltration experiments; well records; and piezometric data) and groundwater flow simulation (i.e. one-dimensional vertical, transient, and variably saturated) were used to design the boundary conditions for 3D Devil's Slide-like problems. Twenty-four simulations of steady-state saturated subsurface flow were conducted in a concept-development mode. Recharge, heterogeneity, and anisotropy are shown to increase fluid pressures for failure-prone locations by up to 18.1, 4.5, and 1.8% respectively. Previous estimates of slope stability, driven by simple water balances, are significantly improved upon with the fluid pressures reported here. The results, for a Devil's Slide-like system, provide a foundation for future investigations
Institute of Scientific and Technical Information of China (English)
刘克涛; 朱家玲; 胡开永; 吴秀杰
2016-01-01
For efficient utilization of a limited geothermal resource in practical projects, the cycle parameters were comprehensively analyzed by combining with the heat transfer performance of the plate heat exchanger, with a variation of flowrate of R245fa. The influence of working fluid flowrate on a 500W ORC system was investigated. Adjusting the working fluid flowrate to an optimal value results in the most efficient heat transfer and hence the optimal heat transfer parameters of the plate heat exchanger can be determined. Therefore, for the ORC systems, optimal working fluid flowrate should be controlled. Using different temperature hot water as the heat source, it is found that the optimal flowrate increases by 6−10 L/h with 5 ℃ increment of hot water inlet temperature. During experiment, lower degree of superheat of the working fluid at the outlet the plate heat exchanger may lead to unstable power generation. It is considered that the plate heat exchanger has a compact construction which makes its bulk so small that liquid mixture causes the unstable power generation. To avoid this phenomenon, the flow area of plate heat exchanger should be larger than the designed one. Alternatively, installing a small shell and tube heat exchanger between the outlet of plate heat exchanger and the inlet of expander can be another solution.
Energy Cost of Avoiding Pressure Oscillations in a Discrete Fluid Power Force System
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen
2015-01-01
In secondary valve controlled discrete fluid power force systems the valve opening trajectory greatly influences the pressure dynamics in the actuator chambers. For discrete fluid power systems featuring hoses of significant length pressure oscillations due to fast valve switching is well...... converters. Further the energy losses introduced during the shifting period is investigated and compared for two valve opening algorithms. The investigation of the energy loss is utilised to quantify the importance of a fast valve switching and the energy cost of reducing pressure oscillations. The paper...... will present measurements comparing pressure dynamics for two valve opening algorithms. In addition the paper will give a theoretical investigation of the energy loss during valve shifting and finally measurements of average power output from the power take-off system in various sea states are compared...
Reliability Based Design of Fluid Power Pitch Systems for Wind Turbines
DEFF Research Database (Denmark)
Liniger, Jesper; Pedersen, Henrik Clemmensen; N. Soltani, Mohsen
2017-01-01
pitch system applied to wind turbines. The results show a good agreement to recent field failure data for offshore turbines where the dominating failure modes are valve, accumulator and leakage. The results are further used for making design improvements to lower the overall risk of the pitch system......This paper presents a qualitative design tool for evaluation of the risk for fluid power pitch systems. The design tool is developed with special attention to industry standard failure analysis methods and is aimed at the early phase of system design. Firstly, the concept of Fault Tree Analysis...
Energy Technology Data Exchange (ETDEWEB)
Shao, Hongbo; Kabilan, Senthil; Stephens, Sean A.; Suresh, Niraj; Beck, Anthon NR; Varga, Tamas; Martin, Paul F.; Kuprat, Andrew P.; Jung, Hun Bok; Um, Wooyong; Bonneville, Alain; Heldebrant, David J.; Carroll, KC; Moore, Joseph; Fernandez, Carlos A.
2015-07-01
Cost-effective creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the feasibility of enhanced geothermal systems (EGS). Current reservoir stimulation entails adverse environmental impacts and substantial economic costs due to the utilization of large volumes of water “doped” with chemicals including rheology modifiers, scale and corrosion inhibitors, biocides, friction reducers among others where, typically, little or no information of composition and toxicity is disclosed. An environmentally benign, CO2-activated, rheoreversible fracturing fluid has recently been developed that significantly enhances rock permeability at effective stress significantly lower than current technology. We evaluate the potential of this novel fracturing fluid for application on geothermal sites under different chemical and geomechanical conditions, by performing laboratory-scale fracturing experiments with different rock sources under different confining pressures, temperatures, and pH environments. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable Polyallylamine (PAA) represent a highly versatile fracturing fluid technology. This fracturing fluid creates/propagates fracture networks through highly impermeable crystalline rock at significantly lower effective stress as compared to control experiments where no PAA was present, and permeability enhancement was significantly increased for PAA compared to conventional hydraulic fracturing controls. This was evident in all experiments, including variable rock source/type, operation pressure and temperature (over the entire range for EGS applications), as well as over a wide range of formation-water pH values. This versatile novel fracturing fluid technology represents a great alternative to industrially available fracturing fluids for cost-effective and competitive geothermal energy production.
Uchino, Junji; Kawasaki, Tadayuki
2009-01-01
Whereas the main measure of dialysis fluid purity is endotoxin (ET) activity in Japan, it is the viability count in Western countries. Because of this difference, little information is available concerning dialysis fluid purity determined in terms of viability count in Japan. Under these circumstances a fact-finding investigation was planned and conducted concerning dialysis fluid purity to demonstrate the effectiveness of dialysis fluid purification measures. 93 medical institutions are equipped with the central dialysis fluid delivery system (CDDS) unique to Japan. Almost all medical institutions surveyed have achieved the purification level of ultrapure dialysis fluid after ETRF, but the methods of ETRF use and management widely vary with each institution so that early validation of the methods of evaluation of ET inhibition and system management is in urgent need. It is also important that simple universal microbial monitoring and purification procedures be diffused far and wide as suggested by the Purification Guidelines proposed by us.
Dynamical analysis of an accelerator-based fluid-fueled subcritical radioactive waste burning system
Woosley, Michael Louis, Jr.
The recent revival of interest in accelerator-driven subcritical fluid-fueled systems is documented. Several important applications of these systems are mentioned. In particular, new applications have focused on the destruction of high-level radioactive waste. Systems can be designed to quickly destroy the actinides and long-lived fission products from light water reactor fuel, weapons plutonium, and other high-level defense wastes. The proposed development of these systems is used to motivate the need for the development of dynamic analysis methods for their nuclear kinetics. A physical description of the Los Alamos Accelerator-Based Conversion (ABC) concept is provided. This system is used as the basis for the kinetics study in this research. The current approach to the dynamic simulation of an accelerator-driven subcritical fluid-fueled system includes three elements: A discrete ordinates model is used to calculate the flux distribution for the source-driven system; A nodal convection model is used to calculate time-dependent isotope and temperature distributions which impact reactivity; A nodal importance weighting model is used to calculate the reactivity impact of temperature and isotope distributions and to feed this information back to the time-dependent nodal convection model. Specific transients which have been analyzed with the current modeling system are discussed. These transients include loss-of-flow and loss-of-cooling accidents, xenon and samarium transients, and cold-plug and overfueling events. The results of various transients have uncovered unpredictable behavior, unresolved design issues, and the need for active control. Modest initiating events can cause significant swings in system temperature and power. The circulation of the fluid fuel can lead to oscillations on the relatively short scale of the loop circulation time. The system responds quickly to reactivity changes because the large neutron source overwhelms the damping effect of delayed
Storage capacity and learning algorithms for two-layer neural networks
Engel, A.; Köhler, H. M.; Tschepke, F.; Vollmayr, H.; Zippelius, A.
1992-05-01
A two-layer feedforward network of McCulloch-Pitts neurons with N inputs and K hidden units is analyzed for N-->∞ and K finite with respect to its ability to implement p=αN random input-output relations. Special emphasis is put on the case where all hidden units are coupled to the output with the same strength (committee machine) and the receptive fields of the hidden units either enclose all input units (fully connected) or are nonoverlapping (tree structure). The storage capacity is determined generalizing Gardner's treatment [J. Phys. A 21, 257 (1988); Europhys. Lett. 4, 481 (1987)] of the single-layer perceptron. For the treelike architecture, a replica-symmetric calculation yields αc~ √K for a large number K of hidden units. This result violates an upper bound derived by Mitchison and Durbin [Biol. Cybern. 60, 345 (1989)]. One-step replica-symmetry breaking gives lower values of αc. In the fully connected committee machine there are in general correlations among different hidden units. As the limit of capacity is approached, the hidden units are anticorrelated: One hidden unit attempts to learn those patterns which have not been learned by the others. These correlations decrease as 1/K, so that for K-->∞ the capacity per synapse is the same as for the tree architecture, whereas for small K we find a considerable enhancement for the storage per synapse. Numerical simulations were performed to explicitly construct solutions for the tree as well as the fully connected architecture. A learning algorithm is suggested. It is based on the least-action algorithm, which is modified to take advantage of the two-layer structure. The numerical simulations yield capacities p that are slightly more than twice the number of degrees of freedom, while the fully connected net can store relatively more patterns than the tree. Various generalizations are discussed. Variable weights from hidden to output give the same results for the storage capacity as does the committee
Optical measurements of absorption changes in two-layered diffusive media
Energy Technology Data Exchange (ETDEWEB)
Fabbri, Francesco [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Sassaroli, Angelo [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Henry, Michael E [McLean Hospital and Department of Psychiatry, Harvard Medical School, 115 Mill Street, Belmont, MA 02478 (United States); Fantini, Sergio [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States)
2004-04-07
We have used Monte Carlo simulations for a two-layered diffusive medium to investigate the effect of a superficial layer on the measurement of absorption variations from optical diffuse reflectance data processed by using: (a) a multidistance, frequency-domain method based on diffusion theory for a semi-infinite homogeneous medium; (b) a differential-pathlength-factor method based on a modified Lambert-Beer law for a homogeneous medium and (c) a two-distance, partial-pathlength method based on a modified Lambert-Beer law for a two-layered medium. Methods (a) and (b) lead to a single value for the absorption variation, whereas method (c) yields absorption variations for each layer. In the simulations, the optical coefficients of the medium were representative of those of biological tissue in the near-infrared. The thickness of the first layer was in the range 0.3-1.4 cm, and the source-detector distances were in the range 1-5 cm, which is typical of near-infrared diffuse reflectance measurements in tissue. The simulations have shown that (1) method (a) is mostly sensitive to absorption changes in the underlying layer, provided that the thickness of the superficial layer is {approx}0.6 cm or less; (2) method (b) is significantly affected by absorption changes in the superficial layer and (3) method (c) yields the absorption changes for both layers with a relatively good accuracy of {approx}4% for the superficial layer and {approx}10% for the underlying layer (provided that the absorption changes are less than 20-30% of the baseline value). We have applied all three methods of data analysis to near-infrared data collected on the forehead of a human subject during electroconvulsive therapy. Our results suggest that the multidistance method (a) and the two-distance partial-pathlength method (c) may better decouple the contributions to the optical signals that originate in deeper tissue (brain) from those that originate in more superficial tissue layers.
Energy Technology Data Exchange (ETDEWEB)
Riffat, S.B.; Omer, S.A. [Nottingham Univ., School of the Built Environment, Nottingham (United Kingdom)
2001-07-01
This paper presents results of computational fluid dynamic (CFD) analysis and experimental investigation of an ejector refrigeration system using methanol as the working fluid. The CFD modelling was used to investigate the effect of the relative position of the primary nozzle exit within the mixing chamber on the performance of the ejector. The results of the CFD were used to obtain the optimum geometry of the ejector, which was then used to design, construct and test a small-scale experimental ejector refrigeration system. Methanol was used as the working fluid, as it has the advantage of being an 'environmentally friendly' refrigerant that does not contribute to global warming and ozone layer depletion. In addition, use of methanol allows the ejector refrigeration system to produce cooling at temperatures below the freezing point of the water, which of course would not be possible with a water ejector refrigeration system. CFD results showed that positioning the nozzle exit at least 0.21 length of the mixing chamber throat's diameter upstream of the entrance of the mixing chamber gave better performance than pushing it into the mixing chamber. Experimental values of coefficient of performance (COP) between 0.2 and 0.4 were obtained at operating conditions achievable using low-grade heat such as solar energy and waste heat. (Author)
Cullimore, B.
1994-01-01
SINDA, the Systems Improved Numerical Differencing Analyzer, is a software system for solving lumped parameter representations of physical problems governed by diffusion-type equations. SINDA was originally designed for analyzing thermal systems represented in electrical analog, lumped parameter form, although its use may be extended to include other classes of physical systems which can be modeled in this form. As a thermal analyzer, SINDA can handle such interrelated phenomena as sublimation, diffuse radiation within enclosures, transport delay effects, and sensitivity analysis. FLUINT, the FLUid INTegrator, is an advanced one-dimensional fluid analysis program that solves arbitrary fluid flow networks. The working fluids can be single phase vapor, single phase liquid, or two phase. The SINDA'85/FLUINT system permits the mutual influences of thermal and fluid problems to be analyzed. The SINDA system consists of a programming language, a preprocessor, and a subroutine library. The SINDA language is designed for working with lumped parameter representations and finite difference solution techniques. The preprocessor accepts programs written in the SINDA language and converts them into standard FORTRAN. The SINDA library consists of a large number of FORTRAN subroutines that perform a variety of commonly needed actions. The use of these subroutines can greatly reduce the programming effort required to solve many problems. A complete run of a SINDA'85/FLUINT model is a four step process. First, the user's desired model is run through the preprocessor which writes out data files for the processor to read and translates the user's program code. Second, the translated code is compiled. The third step requires linking the user's code with the processor library. Finally, the processor is executed. SINDA'85/FLUINT program features include 20,000 nodes, 100,000 conductors, 100 thermal submodels, and 10 fluid submodels. SINDA'85/FLUINT can also model two phase flow
Directory of Open Access Journals (Sweden)
Wang Honglun
2015-02-01
Full Text Available This paper proposes a method for planning the three-dimensional path for low-flying unmanned aerial vehicle (UAV in complex terrain based on interfered fluid dynamical system (IFDS and the theory of obstacle avoidance by the flowing stream. With no requirement of solutions to fluid equations under complex boundary conditions, the proposed method is suitable for situations with complex terrain and different shapes of obstacles. Firstly, by transforming the mountains, radar and anti-aircraft fire in complex terrain into cylindrical, conical, spherical, parallelepiped obstacles and their combinations, the 3D low-flying path planning problem is turned into solving streamlines for obstacle avoidance by fluid flow. Secondly, on the basis of a unified mathematical expression of typical obstacle shapes including sphere, cylinder, cone and parallelepiped, the modulation matrix for interfered fluid dynamical system is constructed and 3D streamlines around a single obstacle are obtained. Solutions to streamlines with multiple obstacles are then derived using weighted average of the velocity field. Thirdly, extra control force method and virtual obstacle method are proposed to deal with the stagnation point and the case of obstacles’ overlapping respectively. Finally, taking path length and flight height as sub-goals, genetic algorithm (GA is used to obtain optimal 3D path under the maneuverability constraints of the UAV. Simulation results show that the environmental modeling is simple and the path is smooth and suitable for UAV. Theoretical proof is also presented to show that the proposed method has no effect on the characteristics of fluid avoiding obstacles.
An Experimental Analysis of Brake Efficiency Using four Fluids in a Disc Brake System
Directory of Open Access Journals (Sweden)
Seth Daniel Oduro
2013-02-01
Full Text Available The paper studies disc brake failure in Mini-buses using an experimental analysis to test the maximum braking force when different brake fluids such as clean, less dirty, dirty and soapy water solution were used in the braking system. The experimental results clearly showed that the soap solution appears to be the best fluid as far as low viscosity and stability of viscosity with increase in temperature are concerned. However, the soap solution is not compatible with other fluid which makes it difficult to be substitute as a clean brake fluid. The result of the Thepra Universal Brake Testing Equipment used for the braking efficiency test indicated that a pedal brake of 117 kN produce a brake force of 0.96 kN for clean brake fluid, 0.91 kN for the less dirty, 0.85 kN for dirty and 1.44 kN for soap solution. The value of 1.44 kN which was achieved when the soap solution was used indicated a positive braking force and the indicating that soap solution could be used to produce a high pedal force within a very short time (about 10-30 min and can therefore be used only in case of emergency. The brake efficiency test indicated that under hot conditions the braking efficiency is reduced and the presence of air in the system renders the braking ineffective because higher pedal force was needed to be able to produce a significant braking force which is noted for causing brake failure.
Institute of Scientific and Technical Information of China (English)
Wang Honglun; Lyu Wentao; Yao Peng; Liang Xiao; Liu Chang
2015-01-01
This paper proposes a method for planning the three-dimensional path for low-flying unmanned aerial vehicle (UAV) in complex terrain based on interfered fluid dynamical system (IFDS) and the theory of obstacle avoidance by the flowing stream. With no requirement of solutions to fluid equations under complex boundary conditions, the proposed method is suitable for situations with complex terrain and different shapes of obstacles. Firstly, by transforming the mountains, radar and anti-aircraft fire in complex terrain into cylindrical, conical, spherical, parallelepiped obstacles and their combinations, the 3D low-flying path planning problem is turned into solving streamlines for obstacle avoidance by fluid flow. Secondly, on the basis of a unified mathematical expression of typical obstacle shapes including sphere, cylinder, cone and parallelepiped, the modulation matrix for interfered fluid dynamical system is constructed and 3D streamlines around a single obstacle are obtained. Solutions to streamlines with multiple obstacles are then derived using weighted average of the velocity field. Thirdly, extra control force method and virtual obstacle method are proposed to deal with the stagnation point and the case of obstacles’ overlapping respectively. Finally, taking path length and flight height as sub-goals, genetic algorithm (GA) is used to obtain optimal 3D path under the maneuverability constraints of the UAV. Simulation results show that the environmental modeling is simple and the path is smooth and suitable for UAV. Theoretical proof is also presented to show that the proposed method has no effect on the characteristics of fluid avoiding obstacles.
Battani, A.; Monnin, C.; Ruffine, L.; Ellouz, N.; Leroy, S. D.
2014-12-01
The area of Western Haiti is located between the Enriquillo-Plantain Garden Fault (EPGF) and Ciabao-Oriente Septentrional fault systems. It has been investigated during the Haiti-SIS cruise (November-December 2012) by heat flow measurements and coring. These two strike-slip fault systems accommodate the relative motion between the Caribbean and North American plates. An aftershock study of the MW= 7, 12 January 2010 earthquake indicated that this event originated along the EPGF fault, while the septentrional fault has not been ruptured for about a century. We focused coring operations on specific zones; faults, basin margins, ridge, deep basins delimated using structural/sedimentological surface data. The objective of the pore-fluid study was to determine both the pathways of the fluids and their origin in relation with the fault activity. A total of 14 Kullenberg cores were collected for fluid sampling and sedimentological analyses. Overall, 99 pore fluids were extracted, using Rhizon® samplers. Major and minor dissolved elements were analyzed. The resulting dataset allows us to identify several diagenetic processes occurring within the upper section of the sedimentary column. For the fault-crossing zones, the vertical chloride and sulphate profiles where the dissolved-element concentrations are close to that of normal seawater suggest seawater downward flow (infiltration). There the faults would then act as recharge zones for fluid circulation. On the opposite, for cores recovered in the basins, dissolved element profiles exhibit variable shapes with sulfate concentration decreasing with depth (indicating organic matter oxydation or anaerobic oxidation of methane) These results will be combined with those from the emerged segment of the EPGF (that can be observed on land in Haiti) in order to have a picture of the hydrologic regime of the fault system, its capacity to act as a recharge zone and conversely to supply deep-seated fluids to the surface (discharge
FLUID-BASED SIMULATION APPROACH FOR HIGH VOLUME CONVEYOR TRANSPORTATION SYSTEMS
Institute of Scientific and Technical Information of China (English)
Ying WANG; Chen ZHOU
2004-01-01
High volume conveyor systems in distribution centers have very large footprint and can handle large volumes and hold thousands of items. Traditional discrete-event cell-based approach to simulate such networks becomes computationally challenging. An alternative approach, in which the traffic is represented by segments of fluid flow of different density instead of individual packages, is presented in this paper to address this challenge. The proposed fluid-based simulation approach is developed using a Hybrid Petri Nets framework. The underlying model is a combination of an extension of a Batches Petri Nets (BPN) and a Stochastic Petri Nets (SPN). The extensions are in the inclusion of random elements and relaxation of certain structural constraints. Some adaptations are also made to fit the target system modeling. The approach is presented with an example.
Macro-scale pseudo-particle modeling for particle-fluid systems
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Pseudo-particle modeling (PPM) is a particle method (PM) proposed in 1996. Though it is effective for the simulation of microscopic particle-fluid systems, its application to practical systems is still limited by computational cost.In this note, we speed up the computation by using a combination of weighted averaging with finite difference techniques to upgrade the particle interactions to a fluid element level, which conforms to the Navier-Stokes equation. The approach, abbreviated to MaPPM, is then applied to the problem of one-dimensional Poiseuille flow with a quantitative comparison to the results of another related PM smoothed particle hydrodynamics (SPH), where the accuracy and efficiency of MaPPM is found to be much better than that of SPH. Flows around a cylinder and multiple freely moving particles are also simulated with the new model, resulting in reasonable flow pattern and drag coefficient. The convergence and robustness of the algorithm prove promising.``
Fluid biomarkers in multiple system atrophy: A review of the MSA Biomarker Initiative.
Laurens, Brice; Constantinescu, Radu; Freeman, Roy; Gerhard, Alexander; Jellinger, Kurt; Jeromin, Andreas; Krismer, Florian; Mollenhauer, Brit; Schlossmacher, Michael G; Shaw, Leslie M; Verbeek, Marcel M; Wenning, Gregor K; Winge, Kristian; Zhang, Jing; Meissner, Wassilios G
2015-08-01
Despite growing research efforts, no reliable biomarker currently exists for the diagnosis and prognosis of multiple system atrophy (MSA). Such biomarkers are urgently needed to improve diagnostic accuracy, prognostic guidance and also to serve as efficacy measures or surrogates of target engagement for future clinical trials. We here review candidate fluid biomarkers for MSA and provide considerations for further developments and harmonization of standard operating procedures. A PubMed search was performed until April 24, 2015 to review the literature with regard to candidate blood and cerebrospinal fluid (CSF) biomarkers for MSA. Abstracts of 1760 studies were retrieved and screened for eligibility. The final list included 60 studies assessing fluid biomarkers in patients with MSA. Most studies have focused on alpha-synuclein, markers of axonal degeneration or catecholamines. Their results suggest that combining several CSF fluid biomarkers may be more successful than using single markers, at least for the diagnosis. Currently, the clinically most useful markers may comprise a combination of the light chain of neurofilament (which is consistently elevated in MSA compared to controls and Parkinson's disease), metabolites of the catecholamine pathway and proteins such as α-synuclein, DJ-1 and total-tau. Beyond future efforts in biomarker discovery, the harmonization of standard operating procedures will be crucial for future success.
DEFF Research Database (Denmark)
Gruber, M.F.; Johnson, C.J.; Tang, C.Y.;
2011-01-01
Forward osmosis is an osmotically driven membrane separation process that relies on the utilization of a large osmotic pressure differential generated across a semi-permeable membrane. In recent years forward osmosis has shown great promise in the areas of wastewater treatment, seawater...... the understanding of membrane systems, models that can accurately encapsulate all significant physical processes occurring in the systems are required. The present study demonstrates a computational fluid dynamics (CFD) model capable of simulating forward osmosis systems with asymmetric membranes. The model...
DEFF Research Database (Denmark)
Andersen, T. O.; Hansen, M. R.; Conrad, Finn
2003-01-01
The development within the engineering industry is ever more in the direction of an integration of electronics both on the component level and system level. This implies improved and more intelligentcomponents with increased funtionality at the same time as the variant creation is made in the ele...... and control can be useful in analysis, synthesis, design and application of mechatronic systems with fluid power actuation. The focus is on system aspects and describes several projects from education and research that utilises the mentioned methods and techniques....
Systems and methods for the detection of low-level harmful substances in a large volume of fluid
Carpenter, Michael V.; Roybal, Lyle G.; Lindquist, Alan; Gallardo, Vincente
2016-03-15
A method and device for the detection of low-level harmful substances in a large volume of fluid comprising using a concentrator system to produce a retentate and analyzing the retentate for the presence of at least one harmful substance. The concentrator system performs a method comprising pumping at least 10 liters of fluid from a sample source through a filter. While pumping, the concentrator system diverts retentate from the filter into a container. The concentrator system also recirculates at least part of the retentate in the container again through the filter. The concentrator system controls the speed of the pump with a control system thereby maintaining a fluid pressure less than 25 psi during the pumping of the fluid; monitors the quantity of retentate within the container with a control system, and maintains a reduced volume level of retentate and a target volume of retentate.
Brown, Philip E.; Lamb, William M.
1989-06-01
Understanding the role of fluids in geologic processes requires a knowledge of the P- V- T properties of fluids over a wide range of conditions. Comparisons of several published equations of state with available experimental data for fluids composed of H 2O and CO 2 lead to the conclusion that the hard-sphere modified Redlich-Kwong equation of state of Kerrick and Jacobs (1981) most accurately predicts the P- V- T properties in this binary system. To model the volumetric properties in the H 2OCO 2NaCl system a formulation is presented involving a linear (ideal) interpolation between a pure-CO 2 isochore predicted by the equation of state of Kerrick. and Jacobs (1981) and an H 2O-NaCl isochore predicted by an empirical equation derived from the regression of available P- V- T data for the H 2O-NaCl system. This formulation is applicable over a wide range of temperatures (>350°C) and pressures (2-10 kbars) and is especially suitable for high pressures and low-to-moderate temperatures (fluid densities ≥ 1.0 cm 3). Determination of the appropriate isochore for an H 2OCO 2NaCl fluid inclusion requires (1) the relative salinity (NaCl/H 2O + NaCl), (2) bulk density of the combined gas and liquid CO 2 phases, and (3) volume percent estimate of the aqueous p the total homogenization temperature. The commonly encountered problem of estimating the volume percents of phases in inclusions may be avoided in some applications, and several new P- X(CO 2) diagrams have been constructed and contoured with (a) the solvi in the mixed volatile system and (b) the measured density of the CO 2 phase. The effects of H 2OCO 2 clathrates during microthermometric observations in the laboratory are evaluated and in most instances can be minimized or avoided. Application of these results to fluid inclusion studies have led to improved determinations of (1) pressures and temperatures of fluid entrapment in a variety of geologic settings and (2) pressures and temperatures of
Sérgio Monteiro Almeida
2015-01-01
The nervous system plays an important role in HIV infection. The purpose of this review is to discuss the indications for cerebrospinal fluid (CSF) analysis in HIV infection in clinical practice. CSF analysis in HIV infection is indicated for the diagnosis of opportunistic infections and co-infections, diagnosis of meningitis caused by HIV, quantification of HIV viral load, and analysis of CNS HIV compartmentalization. Although several CSF biomarkers have been investigated, none are clinicall...
Dynamical systems analysis of fluid transport in time-periodic vortex ring flows
Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.
2006-01-01
It is known that the stable and unstable manifolds of dynamical systems theory provide a powerful tool for understanding Lagrangian aspects of time-periodic flows. In this work we consider two time-periodic vortex ring flows. The first is a vortex ring with an elliptical core. The manifolds provide information about entrainment and detrainment of irrotational fluid into and out of the volume transported with the ring. The likeness of the manifolds with features observed in flow visualization ...
A comparative study of the protein C system in mother's blood, cord blood and amniotic fluid.
Ewa Zekanowska; Waldemar Uszyński; Mieczysław Uszyński; Jarosław Kuczyński; Marek Szymański
2010-01-01
Activated protein C (APC) is an important anticoagulant which plays a role in pathophysiology of pregnancy, e.g. in maintenance of the uteroplacental circulation and development of the fetus as well as in pathogenesis of preeclampsia. The study objective was to compare the levels of the respective components of the protein C system (protein C, PC; protein S, PS; thrombomodulin, TM) as well as thrombin activatable fibrinolysis inhibitor - TAFI in mother's blood, cord blood and amniotic fluid. ...
Computer Software for Design, Analysis and Control of Fluid Power Systems
DEFF Research Database (Denmark)
Conrad, Finn; Sørensen, Torben; Grahl-Madsen, Mads
1999-01-01
This Deliverable presents contributions from SWING's Task 2.3 Analysis of available software solutions. The Deliverable has focus on the results from this analysis having in mind the task objectives·to carry out a thorough analysis of the state-of the-art solutions for fluid power systems modelli...... and modelling IT tools in the implementation planning (WP3) and pilot implementation (WP4), in particular training programme for key people in the individual SME and/or cluster....
STABILITY OF SYSTEM OF TWO-DIMENSIONAL NON-HYDROSTATIC REVOLVING FLUIDS
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Applying the theory of stratification, it is proved that the system of the two-dimensional non-hydrostatic revolving fluids is unstable in the two-order continuous function class. The construction of solution space is given and the solution approach is offered. The sufficient and necessary conditions of the existence of formal solutions are expressed for some typical initial and boundary value problems and the calculating formulae to formal solutions are presented in detail.
MULTIFRACTAL ANALYSIS OF PARTICLE-FLUID SYSTEM IN A CIRCULATING FLUIDIZED BED
Institute of Scientific and Technical Information of China (English)
Liping; Ma; Weixing; Huang; Yanfu; Shi; Huarui; Yu; Jingxu; Zhu
2005-01-01
In this paper, multifractal analysis together with wavelet transform modulus maxima (WTMM) method is used to analyze the fluctuating signals of circulating fluidized bed (CFB). Singularity spectrum shows that the gas-particle flow in CFB has multifractal character. Motion behavior of the particle-fluid system of CFB can be described by singularity spectrum. Intermittency index can be used to determine the transition of flow regime from fast fluidization to pneumatic conveying.
Display of the β-effect in the Black Sea Two-Layer Model
Directory of Open Access Journals (Sweden)
A.A. Pavlushin
2016-10-01
Full Text Available The research is a continuation of a series of numerical experiments on modeling formation of wind currents and eddies in the Black Sea within the framework of a two-layer eddy-resolving model. The main attention is focused on studying the β-effect role. The stationary cyclonic wind is used as an external forcing and the bottom topography is not considered. It is shown that at the β-effect being taken into account, the Rossby waves propagating from east to west are observed both during the currents’ formation and at the statistical equilibrium mode when the mesoscale eddies are formed. In the integral flows’ field the waves are visually manifested in a form of the alternate large-scale cyclonic gyres and zones in which the meso-scale anti-cyclones are formed. This spatial pattern constantly propagates to the west that differs from the results of calculations using the constant Coriolis parameter when the spatially alternate cyclonic and anti-cyclonic vortices are formed, but hold a quasi-stationary position. The waves with the parameters of the Rossby wave first barotropic mode for the closed basin are most clearly pronounced. Interaction of the Rossby waves with large-scale circulation results in intensification of the of the currents’ hydrodynamic instability and in formation of the mesoscale eddies. Significant decrease of kinetic and available potential energy as compared to the values obtained at the constant Coriolis parameter is also a consequence of the eddy formation intensification.
Deposition, Heat Treatment And Characterization of Two Layer Bioactive Coatings on Cylindrical PEEK.
Durham, John W; Rabiei, Afsaneh
2016-09-15
Polyether ether ketone (PEEK) rods were coated via ion beam asssited deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength.
A novel approach to ECG classification based upon two-layered HMMs in body sensor networks.
Liang, Wei; Zhang, Yinlong; Tan, Jindong; Li, Yang
2014-03-27
This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient's ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS) filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs) are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC) in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN) platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.
A Two-Layer Method for Sedentary Behaviors Classification Using Smartphone and Bluetooth Beacons.
Cerón, Jesús D; López, Diego M; Hofmann, Christian
2017-01-01
Among the factors that outline the health of populations, person's lifestyle is the more important one. This work focuses on the caracterization and prevention of sedentary lifestyles. A sedentary behavior is defined as "any waking behavior characterized by an energy expenditure of 1.5 METs (Metabolic Equivalent) or less while in a sitting or reclining posture". To propose a method for sedentary behaviors classification using a smartphone and Bluetooth beacons considering different types of classification models: personal, hybrid or impersonal. Following the CRISP-DM methodology, a method based on a two-layer approach for the classification of sedentary behaviors is proposed. Using data collected from a smartphones' accelerometer, gyroscope and barometer; the first layer classifies between performing a sedentary behavior and not. The second layer of the method classifies the specific sedentary activity performed using only the smartphone's accelerometer and barometer data, but adding indoor location data, using Bluetooth Low Energy (BLE) beacons. To improve the precision of the classification, both layers implemented the Random Forest algorithm and the personal model. This study presents the first available method for the automatic classification of specific sedentary behaviors. The layered classification approach has the potential to improve processing, memory and energy consumption of mobile devices and wearables used.
A two-layer $\\alpha\\omega$ dynamo model, and its implications for 1-D dynamos
Roald, C B
1999-01-01
I will discuss an attempt at representing an interface dynamo in a simplified, essentially 1D framework. The operation of the dynamo is broken up into two 1D layers, one containing the $\\alpha$ effect and the other containing the $\\omega$ effect, and these two layers are allowed to communicate with each other by the simplest possible representation of diffusion, an analogue of Newton's law of cooling. Dynamical back-reaction of the magnetic field on them with diagrams I computed for a comparable purely 1D model. The bifurcation structure shows remarkable similarity, but a couple of subtle changes imply dramatically different physical behaviour for the model. In particular, the solar-like dynamo mode found in the 1-layer model is not stable in the 2-layer version; instead there is an (apparent) homoclinic bifurcation and a sequence of periodic, quasiperiodic, and chaotic modes. I argue that the fragility of these models makes them effectively useless as predictors or interpreters of more complex dynamos.
A Novel Approach to ECG Classification Based upon Two-Layered HMMs in Body Sensor Networks
Directory of Open Access Journals (Sweden)
Wei Liang
2014-03-01
Full Text Available This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient’s ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.
A two-layer recurrent neural network for nonsmooth convex optimization problems.
Qin, Sitian; Xue, Xiaoping
2015-06-01
In this paper, a two-layer recurrent neural network is proposed to solve the nonsmooth convex optimization problem subject to convex inequality and linear equality constraints. Compared with existing neural network models, the proposed neural network has a low model complexity and avoids penalty parameters. It is proved that from any initial point, the state of the proposed neural network reaches the equality feasible region in finite time and stays there thereafter. Moreover, the state is unique if the initial point lies in the equality feasible region. The equilibrium point set of the proposed neural network is proved to be equivalent to the Karush-Kuhn-Tucker optimality set of the original optimization problem. It is further proved that the equilibrium point of the proposed neural network is stable in the sense of Lyapunov. Moreover, from any initial point, the state is proved to be convergent to an equilibrium point of the proposed neural network. Finally, as applications, the proposed neural network is used to solve nonlinear convex programming with linear constraints and L1 -norm minimization problems.
Powerful Amplification Cascades of FRET-Based Two-Layer Nonenzymatic Nucleic Acid Circuits.
Quan, Ke; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Ying, Le; Wang, He; Xie, Nuli; Ou, Min; Wang, Kemin
2016-06-07
Nucleic acid circuits have played important roles in biological engineering and have increasingly attracted researchers' attention. They are primarily based on nucleic acid hybridizations and strand displacement reactions between nucleic acid probes of different lengths. Signal amplification schemes that do not rely on protein enzyme show great potential in analytical applications. While the single amplification circuit often achieves linear amplification that may not meet the need for detection of target in a very small amount, it is very necessary to construct cascade circuits that allow for larger amplification of inputs. Herein, we have successfully engineered powerful amplification cascades of FRET-based two-layer nonenzymatic nucleic acid circuits, in which the outputs of catalyzed hairpin assembly (CHA) activate hybridization chain reactions (HCR) circuits to induce repeated hybridization, allowing real-time monitoring of self-assembly process by FRET signal. The cascades can yield 50000-fold signal amplification with the help of the well-designed and high-quality nucleic acid circuit amplifiers. Subsequently, with coupling of structure-switching aptamer, as low as 200 pM adenosine is detected in buffer, as well as in human serum. To our knowledge, we have for the first time realized real-time monitoring adaptation of HCR to CHA circuits and achieved amplified detection of nucleic acids and small molecules with relatively high sensitivity.
Preliminary Design Report of Fluid System of PDRC Performance Test Facility
Energy Technology Data Exchange (ETDEWEB)
Lee, Tae-Ho; Eoh, Jae-Hyuk; Seong, Seung-Hwan; Han, Ji-Woong; Choi, Byoung-Hae; Kim, Seong-O
2008-10-15
PDRC (Passive Decay Heat Removal Circuit) is a safety grade passive residual heat removal system of KALIMER-600. In order to assess the long- and short-term cooling capabilities of PDRC and produce the experimental data for the verification of the performance and safety analysis codes, PDRC performance test was planned for. In this study, the overall design requirements and the preliminary design data for the fluid system of test facility are presented. The fluid system of the facility is composed of the primary heat transport system, the PDRC, the IHX air cooling system and the sodium supply/purification system. The preliminarily designed facility is scaled-down to 1/4 for length, 1/400 for volume from the primary heat transport system and the PDRC of KALIMER-600 based on a reliable scaling method. It can simulate the cooling of primary heat transport system for the full temperature condition in case of the reactor and pump trips. The produced preliminary design data will be used in the future as the basic information for a detailed design, an establishment of experimental requirement and an assessment of the appropriateness of facility design.
MATSUMAE, Mitsunori; SATO, Osamu; HIRAYAMA, Akihiro; HAYASHI, Naokazu; TAKIZAWA, Ken; ATSUMI, Hideki; SORIMACHI, Takatoshi
2016-01-01
Cerebrospinal fluid (CSF) plays an essential role in maintaining the homeostasis of the central nervous system. The functions of CSF include: (1) buoyancy of the brain, spinal cord, and nerves; (2) volume adjustment in the cranial cavity; (3) nutrient transport; (4) protein or peptide transport; (5) brain volume regulation through osmoregulation; (6) buffering effect against external forces; (7) signal transduction; (8) drug transport; (9) immune system control; (10) elimination of metabolites and unnecessary substances; and finally (11) cooling of heat generated by neural activity. For CSF to fully mediate these functions, fluid-like movement in the ventricles and subarachnoid space is necessary. Furthermore, the relationship between the behaviors of CSF and interstitial fluid in the brain and spinal cord is important. In this review, we will present classical studies on CSF circulation from its discovery over 2,000 years ago, and will subsequently introduce functions that were recently discovered such as CSF production and absorption, water molecule movement in the interstitial space, exchange between interstitial fluid and CSF, and drainage of CSF and interstitial fluid into both the venous and the lymphatic systems. Finally, we will summarize future challenges in research. This review includes articles published up to February 2016. PMID:27245177
Explicit high-order noncanonical symplectic algorithms for ideal two-fluid systems
Xiao, Jianyuan; Qin, Hong; Morrison, Philip J.; Liu, Jian; Yu, Zhi; Zhang, Ruili; He, Yang
2016-11-01
An explicit high-order noncanonical symplectic algorithm for ideal two-fluid systems is developed. The fluid is discretized as particles in the Lagrangian description, while the electromagnetic fields and internal energy are treated as discrete differential form fields on a fixed mesh. With the assistance of Whitney interpolating forms [H. Whitney, Geometric Integration Theory (Princeton University Press, 1957); M. Desbrun et al., Discrete Differential Geometry (Springer, 2008); J. Xiao et al., Phys. Plasmas 22, 112504 (2015)], this scheme preserves the gauge symmetry of the electromagnetic field, and the pressure field is naturally derived from the discrete internal energy. The whole system is solved using the Hamiltonian splitting method discovered by He et al. [Phys. Plasmas 22, 124503 (2015)], which was been successfully adopted in constructing symplectic particle-in-cell schemes [J. Xiao et al., Phys. Plasmas 22, 112504 (2015)]. Because of its structure preserving and explicit nature, this algorithm is especially suitable for large-scale simulations for physics problems that are multi-scale and require long-term fidelity and accuracy. The algorithm is verified via two tests: studies of the dispersion relation of waves in a two-fluid plasma system and the oscillating two-stream instability.
Institute of Scientific and Technical Information of China (English)
CHEN Xiaozhi; XU Hao; TANG Dazhen; ZHANG Junfeng; HU Xiaolan; TAO Shu; CAI Yidong
2009-01-01
Based on the comprehensive study of core samples, well testing data, and reservoir fluid properties, the construction and the distribution of the abnormal pressure systems of the Huatugou oil field in Qaidam Basin are discussed. The correlation between the pressure systems and hydrocarbon accumulation is addressed by analyzing the corresponding fluid characteristics. The results show that the Huatugou oil field as a whole has low formation pressure and low fluid energy; therefore, the hydrocarbons are hard to migrate, which facilitates the forming of primary reservoirs. The study reservoirs, located at the Xiayoushashan Formation (N_2~1) and the Shangganchaigou Formation (N_1) are relatively shallow and have medium porosity and low permeability. They are abnormal low-pressure reservoirs with an average formation pressure coefficient of 0.61 and 0.72 respectively. According to the pressure coefficient and geothermal anomaly, the N_1 and N_2~1 Formations belong to two independent temperature-pressure systems, and the former has slightly higher energy. The low-pressure compartments consist of a distal bar as the main body, prodeita mud as the top boundary, and shore and shallow lake mud or algal mound as the bottom boundary. They are vertically overlapped and horizontally paralleled. The formation water is abundant in the Cl~- ion and can be categorized as CaCl_2 type with high salinity, which indicates that the abnormal low-pressure compartments are in good sealing condition and beneficial for oil and gas accumulation and preservation.
A dural lymphatic vascular system that drains brain interstitial fluid and macromolecules.
Aspelund, Aleksanteri; Antila, Salli; Proulx, Steven T; Karlsen, Tine Veronica; Karaman, Sinem; Detmar, Michael; Wiig, Helge; Alitalo, Kari
2015-06-29
The central nervous system (CNS) is considered an organ devoid of lymphatic vasculature. Yet, part of the cerebrospinal fluid (CSF) drains into the cervical lymph nodes (LNs). The mechanism of CSF entry into the LNs has been unclear. Here we report the surprising finding of a lymphatic vessel network in the dura mater of the mouse brain. We show that dural lymphatic vessels absorb CSF from the adjacent subarachnoid space and brain interstitial fluid (ISF) via the glymphatic system. Dural lymphatic vessels transport fluid into deep cervical LNs (dcLNs) via foramina at the base of the skull. In a transgenic mouse model expressing a VEGF-C/D trap and displaying complete aplasia of the dural lymphatic vessels, macromolecule clearance from the brain was attenuated and transport from the subarachnoid space into dcLNs was abrogated. Surprisingly, brain ISF pressure and water content were unaffected. Overall, these findings indicate that the mechanism of CSF flow into the dcLNs is directly via an adjacent dural lymphatic network, which may be important for the clearance of macromolecules from the brain. Importantly, these results call for a reexamination of the role of the lymphatic system in CNS physiology and disease.
Kazantsev, Victor; Pimashkin, Alexey
2007-09-01
We propose two-layer architecture of associative memory oscillatory network with directional interlayer connectivity. The network is capable to store information in the form of phase-locked (in-phase and antiphase) oscillatory patterns. The first (input) layer takes an input pattern to be recognized and their units are unidirectionally connected with all units of the second (control) layer. The connection strengths are weighted using the Hebbian rule. The output (retrieved) patterns appear as forced-phase locked states of the control layer. The conditions are found and analytically expressed for pattern retrieval in response on incoming stimulus. It is shown that the system is capable to recover patterns with a certain level of distortions or noises in their profiles. The architecture is implemented with the Kuramoto phase model and using synaptically coupled neural oscillators with spikes. It is found that the spiking model is capable to retrieve patterns using the spiking phase that translates memorized patterns into the spiking phase shifts at different time scales.
Guan, C; Xie, H J; Wang, Y Z; Chen, Y M; Jiang, Y S; Tang, X W
2014-01-01
An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems.
Linear stability analysis and direct numerical simulation of two layer channel flow
Sahu, Kirti Chandra
2016-01-01
We study the stability of two-fluid flow through a plane channel at Reynolds numbers of a hundred to a thousand in the linear and nonlinear regimes. The two fluids have the same density but different viscosities. The fluids, when miscible, are separated from each other by a mixed layer of small but finite thickness, across which viscosity changes from that of one fluid to that of the other. When immiscible, the interface is sharp. Our study spans a range of Schmidt numbers, viscosity ratios and location and thickness of the mixed layer. A region of instability distinct from that of the Tollmien-Schlichting mode is obtained at moderate Reynolds numbers. We show that the overlap of the layer of viscosity-stratification with the critical layer of the dominant disturbance provides a mechanism for this instability. At very low values of diffusivity, the miscible flow behaves exactly like the immiscible in terms of stability characteristics. High levels of miscibility make the flow more stable. At intermediate leve...
Stability of two-layer Couette flow with application to drag reduction
Mohammadi, Alireza; Smits, Alexander J.
2016-11-01
We consider the linear stability of flows composed of two superposed fluids in Couette flow in order to improve our understanding of the longevity and performance of superhydrophobic surfaces (SHS) or liquid-infused surfaces (LIS) which are important for drag reduction. Here, we assume that the fluids are immiscible, incompressible, and Newtonian with constant properties. Single-fluid Couette flow is known to be linearly stable for any Reynolds number. However, inclusion of the second layer of fluid enriches the problem and introduces five new parameters: viscosity ratio, density ratio, thickness ratio, Froude number and Weber number. Two kinds of instability can appear: an unstable interfacial mode, and a Tollmein-Schlichting mode. In this work we parametrically study the flow stability with specific emphasis on the effects of viscosity ratio, interfacial tension, and thickness ratio. Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Office of Naval Research (ONR) through MURI Grants N00014-12-1-0875 and N00014-12-1-0962 (Program Manager Dr. Ki-Han Kim).
Verweij, J.M.
1999-01-01
The reconstruction of the post-Carboniferous hydrogeohistory of the onshore and offshore Netherlands is part of an ongoing TNO project on fluid flow systems analysis on geological timescales. The scope of the project is to assess the present-day hydrogeological and fluid flow conditions of the
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
A novel combined power and heat generation system was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger and a commercial R134a-based heat pump subsystem. The advantages of the novel combined power and heat generation system are free of using additional cooling water circling system for the power generation subsystem as well as maximizing the use of thermal energy in the low-temperature geothermal source. The main purpose is to identify suitable working fluids (wet, isentropic and dry flu-ids) which may yield high PPR (the ratio of power produced by the power generation subsystem to power consumed by the heat pump subsystem) value and QQR (the ratio of heat supplied to the user to heat produced by the geothermal source) value. Parameters under investigation were evaporating temperature, PPR value and QQR value. Results indicate that there exits an optimum evaporating temperature to maximize the PPR value and minimize the QQR value at the same time for individual fluid. And dry fluids show higher PPR values but lower QQR values. NH3 and R152a outstand among wet fluids. R134a out-stands among isentropic fluids. R236ea, R245ca, R245fa, R600 and R600a outstand among dry fluids. R236ea shows the highest PPR value among the recommended fluids.
Tardani, Daniele; Reich, Martin; Deditius, Artur P.; Chryssoulis, Stephen; Sánchez-Alfaro, Pablo; Wrage, Jackie; Roberts, Malcolm P.
2017-05-01
Over the past few decades several studies have reported that pyrite hosts appreciable amounts of trace elements which commonly occur forming complex zoning patterns within a single mineral grain. These chemical zonations in pyrite have been recognized in a variety of hydrothermal ore deposit types (e.g., porphyry Cu-Mo-Au, epithermal Au deposits, iron oxide-copper-gold, Carlin-type and Archean lode Au deposits, among others), showing, in some cases, marked oscillatory alternation of metals and metalloids in pyrite growth zones (e.g., of Cu-rich, As-(Au, Ag)-depleted zones and As-(Au, Ag)-rich, Cu-depleted zones). This decoupled geochemical behavior of Cu and As has been interpreted as a result of chemical changes in ore-forming fluids, although direct evidence connecting fluctuations in hydrothermal fluid composition with metal partitioning into pyrite growth zones is still lacking. In this study, we report a comprehensive trace element database of pyrite from the Tolhuaca Geothermal System (TGS) in southern Chile, a young and active hydrothermal system where fewer pyrite growth rims and mineralization events are present and the reservoir fluid (i.e. ore-forming fluid) is accessible. We combined the high-spatial resolution and X-ray mapping capabilities of electron microprobe analysis (EMPA) with low detection limits and depth-profiling capacity of secondary-ion mass spectrometry (SIMS) in a suite of pyrite samples retrieved from a ∼1 km drill hole that crosses the argillic (20-450 m) and propylitic (650-1000 m) alteration zones of the geothermal system. We show that the concentrations of precious metals (e.g., Au, Ag), metalloids (e.g., As, Sb, Se, Te), and base and heavy metals (e.g., Cu, Co, Ni, Pb) in pyrite at the TGS are significant. Among the elements analyzed, As and Cu are the most abundant with concentrations that vary from sub-ppm levels to a few wt.% (i.e., up to ∼5 wt.% As, ∼1.5 wt.% Cu). Detailed wavelength-dispersive spectrometry (WDS) X
Pustovalov, V. K.; Astafyeva, L. G.; Zharov, V. P.
2013-12-01
Modeling of nonlinear dependences of optical properties of spherical two-layered gold core and some material shell nanoparticles (NPs) placed in water on parameters of core and shell was carried out on the basis of the extended Mie theory. Efficiency cross-sections of absorption, scattering and extinction of radiation with wavelength 532 nm by core-shell NPs in the ranges of core radii r00=5-40 nm and of relative NP radii r1/r00=1-8 were calculated (r1-radius of two-layered nanoparticle). Shell materials were used with optical indexes in the ranges of refraction n1=0.2-1.5 and absorption k1=0-3.5 for the presentation of optical properties of wide classes of shell materials (including dielectrics, metals, polymers, vapor shell around gold core). Results show nonlinear dependences of optical properties of two-layered NPs on optical indexes of shell material, core r00 and relative NP r1/r00 radii. Regions with sharp decrease and increase of absorption, scattering and extinction efficiency cross-sections with changing of core and shell parameters were investigated. These dependences should be taken into account for applications of two-layered NPs in laser nanomedicine and optical diagnostics of tissues. The results can be used for experimental investigation of shell formation on NP core and optical determination of geometrical parameters of core and shell of two-layered NPs.
Dynamical systems analysis of fluid transport in time-periodic vortex ring flows
Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.
2006-04-01
It is known that the stable and unstable manifolds of dynamical systems theory provide a powerful tool for understanding Lagrangian aspects of time-periodic flows. In this work we consider two time-periodic vortex ring flows. The first is a vortex ring with an elliptical core. The manifolds provide information about entrainment and detrainment of irrotational fluid into and out of the volume transported with the ring. The likeness of the manifolds with features observed in flow visualization experiments of turbulent vortex rings suggests that a similar process might be at play. However, what precise modes of unsteadiness are responsible for stirring in a turbulent vortex ring is left as an open question. The second situation is that of two leapfrogging rings. The unstable manifold shows striking agreement with even the fine features of smoke visualization photographs, suggesting that fluid elements in the vicinity of the manifold are drawn out along it and begin to reveal its structure. We suggest that interpretations of these photographs that argue for complex vorticity dynamics ought to be reconsidered. Recently, theoretical and computational tools have been developed to locate structures analogous to stable and unstable manifolds in aperiodic, or finite-time systems. The usefulness of these analogs is demonstrated, using vortex ring flows as an example, in the paper by Shadden, Dabiri, and Marsden [Phys. Fluids 18, 047105 (2006)].
Near-surface gravity actuated pipe (GAP{sup TM}) system for Brazilian deepwater fluid transfer
Energy Technology Data Exchange (ETDEWEB)
Fromage, Lionel; Brown, Paul A. [SBM Offshore (Monaco)
2009-12-19
The recent discovery of new deep water and ultra-deep water oil and gas fields offshore Brazil, including pre-salt reservoirs, has become a focal point for field development Operators and Contractors. The aggressive nature of fluids (sour, high density) in combination with deeper waters implies potential flow assurance issues. These issues challenge riser and pipeline technology to find cost effective solutions for hydrocarbon fluid transfer in field development scenarios involving phased tied-back. The near-surface GAP{sup TM}, system (Gravity Actuated Pipe{sup TM}), which has been in operation for more than two years on the Kikeh field offshore Malaysia in 1325 m of water between a Dry Tree Unit (SPAR) and a turret-moored FPSO, is considered to meet these challenges since such a product is quasi independent of water depth and takes advantage of being near surface to optimize flow assurance. Furthermore the GAP{sup TM} has undergone technical upgrades when compared to the Kikeh project in order to make it suitable for the more hostile met ocean conditions offshore Brazil. This paper presents the design features, the construction and assembly plans in Brazil and the offshore installation of a GAP fluid transfer system for operation in Brazilian deep waters. (author)
Trejos, Víctor M; Gil-Villegas, Alejandro
2012-05-14
Thermodynamic properties of quantum fluids are described using an extended version of the statistical associating fluid theory for potentials of variable range (SAFT-VR) that takes into account quantum corrections to the Helmholtz free energy A, based on the Wentzel-Kramers-Brillouin approximation. We present the theoretical background of this approach (SAFT-VRQ), considering two different cases depending on the continuous or discontinuous nature of the particles pair interaction. For the case of continuous potentials, we demonstrate that the standard Wigner-Kirkwood theory for quantum fluids can be derived from the de Broglie-Bohm formalism for quantum mechanics that can be incorporated within the Barker and Henderson perturbation theory for liquids in a straightforward way. When the particles interact via a discontinuous pair potential, the SAFT-VR method can be combined with the perturbation theory developed by Singh and Sinha [J. Chem. Phys. 67, 3645 (1977); and ibid. 68, 562 (1978)]. We present an analytical expression for the first-order quantum perturbation term for a square-well potential, and the theory is applied to model thermodynamic properties of hydrogen, deuterium, neon, and helium-4. Vapor-liquid equilibrium, liquid and vapor densities, isochoric and isobaric heat capacities, Joule-Thomson coefficients and inversion curves are predicted accurately with respect to experimental data. We find that quantum corrections are important for the global behavior of properties of these fluids and not only for the low-temperature regime. Predictions obtained for hydrogen compare very favorably with respect to cubic equations of state.
Trejos, Víctor M.; Gil-Villegas, Alejandro
2012-05-01
Thermodynamic properties of quantum fluids are described using an extended version of the statistical associating fluid theory for potentials of variable range (SAFT-VR) that takes into account quantum corrections to the Helmholtz free energy A, based on the Wentzel-Kramers-Brillouin approximation. We present the theoretical background of this approach (SAFT-VRQ), considering two different cases depending on the continuous or discontinuous nature of the particles pair interaction. For the case of continuous potentials, we demonstrate that the standard Wigner-Kirkwood theory for quantum fluids can be derived from the de Broglie-Bohm formalism for quantum mechanics that can be incorporated within the Barker and Henderson perturbation theory for liquids in a straightforward way. When the particles interact via a discontinuous pair potential, the SAFT-VR method can be combined with the perturbation theory developed by Singh and Sinha [J. Chem. Phys. 67, 3645 (1977); Singh and Sinha J. Chem. Phys. 68, 562 (1978)]. We present an analytical expression for the first-order quantum perturbation term for a square-well potential, and the theory is applied to model thermodynamic properties of hydrogen, deuterium, neon, and helium-4. Vapor-liquid equilibrium, liquid and vapor densities, isochoric and isobaric heat capacities, Joule-Thomson coefficients and inversion curves are predicted accurately with respect to experimental data. We find that quantum corrections are important for the global behavior of properties of these fluids and not only for the low-temperature regime. Predictions obtained for hydrogen compare very favorably with respect to cubic equations of state.
Li-ion battery cooling system integrates in nano-fluid environment
Tran, Lien; Lopez, Jorge; Lopez, Jesus; Uriostegui, Altovely; Barrera, Avery; Wiggins, Nathanial
2017-02-01
In this design challenge by the Texas Space Grant Consortium, the researchers design a cooling system for a lithium-ion battery. Lithium-ion batteries are an effective and reliable source of energy for small, portable devices. However, similar to other existing sources of energy, there is always a problem with overheating. The objective is to design a cooling system for lithium-ion batteries that will work in a zero gravity environment for orbital and interplanetary space systems. The system is to serve as a backup battery and a signal booster that can be incorporated into a spacesuit. The design must be able to effectively cool the batteries without the use of an atmosphere to carry away heat but also be a lightweight and reliable design. The design incorporates carbon nanotubes suspended in distilled water creating a nano-fluid environment. This design must include a failsafe in the event of thermal runaway, a problem common to lithium-ion batteries. This failsafe will completely shut off the system if the batteries reach a certain temperature. A cooling system that incorporates nano-fluids will achieve a lightweight and efficient way of cooling batteries.
Li-ion battery cooling system integrates in nano-fluid environment
Tran, Lien; Lopez, Jorge; Lopez, Jesus; Uriostegui, Altovely; Barrera, Avery; Wiggins, Nathanial
2016-10-01
In this design challenge by the Texas Space Grant Consortium, the researchers design a cooling system for a lithium-ion battery. Lithium-ion batteries are an effective and reliable source of energy for small, portable devices. However, similar to other existing sources of energy, there is always a problem with overheating. The objective is to design a cooling system for lithium-ion batteries that will work in a zero gravity environment for orbital and interplanetary space systems. The system is to serve as a backup battery and a signal booster that can be incorporated into a spacesuit. The design must be able to effectively cool the batteries without the use of an atmosphere to carry away heat but also be a lightweight and reliable design. The design incorporates carbon nanotubes suspended in distilled water creating a nano-fluid environment. This design must include a failsafe in the event of thermal runaway, a problem common to lithium-ion batteries. This failsafe will completely shut off the system if the batteries reach a certain temperature. A cooling system that incorporates nano-fluids will achieve a lightweight and efficient way of cooling batteries.
Chaos control and impact suppression in rotor-bearing system using magnetorheological fluid
Piccirillo, V.; Balthazar, J. M.; Tusset, A. M.
2015-11-01
In this paper a general dynamic model of a rotor-bearing system using magnetorheological fluid (MR) is presented. The mathematical model of the rotor-bearing system results from a Jeffcott rotor with two-degrees of freedom and discontinuous supports. The effect of magnetorheological fluid on vibration is investigated based on a model of a modified LuGre dynamical friction model. A comparison with equivalent rotor-bearing system is made to verify the contribution of MR in this system. In this study two different implementations of the control procedure are presented, one eliminating the chaotic behavior and the second suppressing the unbalancing vibration so as to avoid impact in rotor-bearing system. First, to control the undesirable chaos in rotor-bearing system a damped passive control methodology is used. On the other hand, to suppressing the impact vibration, the Fuzzy Logic Control is considered. Results demonstrate that undesirable behaviors of rotor can be avoided by varying the damping force.
Star polymers: study of fluid-fluid transitions in a system with a repulsive ultrasoft-core
Verso, F L; Reatto, L
2003-01-01
We study a model for star polymers in solution which, in addition to the ultrasoft repulsive interaction of entropic origin, has an attractive interpolymer interaction at longer range. This attraction can arise from a suitable tuning of the solvent and solute properties. For this model we study the phase diagram using mean-field theory and two fluid-state theories, the modified hypernetted chain (MHNC) integral equation and the hierarchical reference theory, and we explore star polymers with a different number of arms f (f = 12, 24, 32, 40). All three theories give the same topology for the phase diagram in the presence of attraction. When the strength of the interaction is strong enough a fluid-fluid phase transition appears but the coexistence curve in the density-temperature (strength of attraction) bifurcates at a triple point into two lines of coexistence terminating at two critical points. This peculiar phase behaviour is related to the unusual form of the repulsive contribution V sub r sub e sub p (r):...
THE SEMI-GEOSTROPHIC ADAPTATION PROCESS WITH TWO-LAYER BAROCLINIC MODEL IN LOW LATITUDE ATMOSPHERE
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
In this paper, the adaptation process in low latitude atmosphere is discussed by means of a two-layer baroclinic model on the equator β plane, showing that the adaptation process in low latitude is mainly dominated by the internal inertial gravity waves. The initial ageostrophic energy is dispersed by the internal inertial gravity waves, and as a result, the geostrophic motion is obtained in zonal direction while the ageostrophic motion maintains in meridional direction, which can be called semi-geostrophic balance in barotropic model as well as semi-thermal-wind balance in baroclinic model. The vertical motion is determined both by the distribution of the initial vertical motion and that of the initial vertical motion tendency, but it is unrelated to the initial potential vorticity. Finally, the motion tends to be horizontal. The discussion of the physical mechanism of the semi-thermal-wind balance in low latitude atmosphere shows that the achievement of the semi-thermal-wind balance is due to the adjustment between the stream field and the temperature field through the horizontal convergence and divergence which is related to the vertical motion excited by the internal inertial gravity waves. The terminal adaptation state obtained shows that the adaptation direction between the mean temperature field and the shear flow field is determined by the ratio of the scale of the initial ageostrophic disturbance to the scale of one character scale related to the baroclinic Rossby radius of deformation. The shear stream field adapts to the mean temperature field when the ratio is greater than 1, and the mean temperature field adapts to the shear stream field when the ratio is smaller than 1.
Energy Technology Data Exchange (ETDEWEB)
Boles, James [Professor
2013-05-24
Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.
Fluid-solid transition in simple systems using density functional theory
Energy Technology Data Exchange (ETDEWEB)
Bharadwaj, Atul S.; Singh, Yashwant [Department of Physics, Banaras Hindu University, Varanasi-221 005 (India)
2015-09-28
A free energy functional for a crystal which contains both the symmetry-conserved and symmetry-broken parts of the direct pair correlation function has been used to investigate the fluid-solid transition in systems interacting via purely repulsive Weeks-Chandler-Anderson Lennard–Jones potential and the full Lennard–Jones potential. The results found for freezing parameters for the fluid-face centred cubic crystal transition are in very good agreement with simulation results. It is shown that although the contribution made by the symmetry broken part to the grand thermodynamic potential at the freezing point is small compared to that of the symmetry conserving part, its role is crucial in stabilizing the crystalline structure and on values of the freezing parameters.
Pogorelova, T N; Gunko, V O; Linde, V A
2014-01-01
Metabolism of glutamine and glutamic acid has been investigated in the placenta and amniotic fluid under conditions of placental insufficiency. The development of placental insufficiency is characterized by the increased content of glutamic acid and a decrease of glutamine in both placenta and amniotic fluid. These changes changes were accompanied by changes in the activity of enzymes involved in the metabolism of these amino acids. There was a decrease in glutamate dehydrogenase activity and an increase in glutaminase activity with the simultaneous decrease of glutamine synthetase activity. The compensatory decrease in the activity of glutamine keto acid aminotransferase did not prevent a decrease in the glutamine level. The impairments in the system glutamic acid-glutamine were more pronounced during the development of premature labor.
Simulation of non-equilibrium two-phase flow in single component fluid systems
Energy Technology Data Exchange (ETDEWEB)
Hoyer, Norbert [Scandpower A/S, Kjeller (Norway)
1996-12-31
Traditionally, two-phase flow has been modelled by separate correlations for void fraction, pressure drop and flow regimes. A more unified approach, which treats flow regimes as an integral part of the two-fluid model is described in this work. A general, transient simulator for steam-water/inert gas systems has been developed. MONA is based on a full two-fluid, three field, nonequilibrium, nonhomogeneous two-phase flow model. It includes further an extensive heat and mass transfer package. The major contribution for MONA validation comes from the FRIGG loop experiments, covering a wide range of parameters like geometry, flow, subcooling, pressure and heat flux. Both validation against steady state and dynamic experiments has been carried out, the former comprising void fractions, pressure drops as well as natural and forced circulation flow rates while the latter consists of boiling instability analysis. 69 refs., 41 figs., 5 tabs.
A Hydrostatic Bearing Test System for Measuring Bearing Load Using Magnetic-Fluid Lubricants.
Weng, Huei Chu; Chen, Lu-Yu
2016-05-01
This paper conducts a study on the design of a hydrostatic bearing test system. It involves the determination of viscous properties of magnetic-fluid lubricants. The load of a hydrostatic thrust bearing using a water-based magnetite nanofluid of varying volume flow rate is measured under an applied external induction field via the test system. Results reveal that the presence of nanoparticles in a carrier liquid would cause an enhanced bearing load. Such an effect could be further magnified by increasing the lubricant volume flow rate or the external induction field strength.
Remarks on Hierarchic Control for a Linearized Micropolar Fluids System in Moving Domains
Energy Technology Data Exchange (ETDEWEB)
Jesus, Isaías Pereira de, E-mail: isaias@ufpi.edu.br [Universidade Federal do Piauí, Dpto. Matemática (Brazil)
2015-12-15
We study a Stackelberg strategy subject to the evolutionary linearized micropolar fluids equations in domains with moving boundaries, considering a Nash multi-objective equilibrium (non necessarily cooperative) for the “follower players” (as is called in the economy field) and an optimal problem for the leader player with approximate controllability objective. We will obtain the following main results: the existence and uniqueness of Nash equilibrium and its characterization, the approximate controllability of the linearized micropolar system with respect to the leader control and the existence and uniqueness of the Stackelberg–Nash problem, where the optimality system for the leader is given.
Energy Technology Data Exchange (ETDEWEB)
Schiele, O.; Florjancie, D.
1978-02-14
A nuclear steam supply system is described wherein each of a plurality of centrifugal pumps begins to operate with full cavitation in response to an abrupt drop of system pressure in the event of leakage. This is achieved by influencing the net positive suction head of each pump over the entire range of fluid flow and/or by influencing the net positive suction head upstream of the pumps. The first mode of causing the pumps to operate with full cavitation includes an appropriate selection of the inlet angle and/or inlet diameter of pump impeller, or the provision of suitably curved guide vanes in the pumps. The second mode includes interrupting the admission of undercooled fluid into the system upstream of the pumps.
Institute of Scientific and Technical Information of China (English)
Jinghai Li
2005-01-01
While science continues to extend to two extremes - micro-scale towards dimensions even smaller than elemental particles and mega-scale even beyond the universe, one recognizes that reductionism is not sufficient to solve many problems we encounter in engineering, which are likely characterized by nonlinearity, nonequilibrium and dissipative multi-scale structures. On the other hand, the common features of these nonlinear systems, such as bifurcation, state multiplicity and self-organization, have attracted much attention, leading to the approaches of the so-called complexity science which has become a focus not only in natural science and engineering science, but also in social science.However, no effective methodology has been established to understand these complex systems, though noticeable progress has been achieved in studying these systems, such as particle-fluid multi-phase systems. Multi-scale methodology has been considered as a promising methodology to tackle complex systems due to its capability in correlating phenomena at different scales. In this presentation, we shall review the development of the multi-scale methodology and its applications to particle-fluid systems, elucidating the essential relevance of complex systems and the challenging problems in chemical engineering.Multi-scale structure is considered to be the focus in studying complex systems, particularly, correlation between phenomena at different scales, compromise between different dominant mechanisms, coupling between spatial and temporal structural changes and critical phenomena occurring in these systems - these are the four critical issues in understanding complex systems. We first propose that by analyzing particle-fluid systems complex systems can be formulated as a multi-objective variational problem. Such an analytical multi-scale method will be reviewed in particular by analyzing the above four critical issues and by showing its 20-year development at IPE from a rough idea to
Velocity Profile in a Two-Layer Kolmogorov-Like Flow
Suri, Balachandra; Mitchell, Radford; Grigoriev, Roman O; Schatz, Michael F
2013-01-01
In this article we discuss flows in shallow, stratified horizontal layers of two immiscible fluids. The top layer is an electrolyte which is electromagnetically driven and the bottom layer is a dielectric fluid. Using a quasi-two-dimensional approximation, we derive the depth-averaged two-dimensional (2D) vorticity equation which includes a prefactor to the advection term, previously unaccounted for. In addition, we study how the horizontal components of velocity vary in the vertical direction. For a Kolmogorov-like flow, we evaluate analytical expressions for the coefficients in the generalized 2D vorticity equation, uncovering their dependence on experimental parameters. To test the accuracy of these estimates, we experimentally measure the horizontal velocity fields at the free-surface and at the electrolyte-dielectric interface using particle image velocimetry (PIV). We show that there is excellent agreement between the analytical predictions and the experimental measurements. Our analysis shows that by i...
Institute of Scientific and Technical Information of China (English)
ZHANG; Renhua; SUN; Xiaomin; WANG; Weimin; XU; Jinping; ZH
2005-01-01
Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.
Taetz, Stephan; John, Timm; Bröcker, Michael; Spandler, Carl
2016-11-01
A complex high-pressure/low-temperature vein system that cross-cuts eclogitic host rocks of the Pouébo Eclogite Melange (northern New Caledonia) records the prograde blueschist-to-eclogite transition and associated formation of garnet-quartz-phengite veins. Geothermobarometry (Grt-Cpx-Ph, Zr-in-rutile) and pseudosection calculations indicate peak metamorphic conditions of ca. 540 °C and 1.9-2.2 GPa. Petrological and geochemical observations as well as pseudosection modelling suggest that the main vein network is formed by dehydration processes that collected internally derived fluids related to the breakdown of hydrous phases (amphibole, chlorite, epidote) during prograde metamorphism. The lower solid volume of the newly formed phases and the associated increase in pore fluid pressure lead to the formation of veins that allowed for accumulation and channelized evacuation of these fluids. Such veins do not show metasomatic alteration selvages because the fluid-rock system had been in chemical equilibrium. A second vein type (transport veins) records the superimposed influx of external fluids with slightly different composition that most likely are related to similar dehydration reactions in other parts of the subducting slab. Due to the source-rock-imposed compositional differences, these fluids are not in equilibrium with the infiltrated rock volume and induce the formation of distinct metasomatic selvages by dissolution-precipitation processes. Mass-balance calculations show that Ca, Na and Li are added to the selvage by the external fluid. LILE and to a lesser extend also HREE are mobilized and removed from the selvage. The LREE are predominantly buffered by newly formed minerals (e.g. epidote). Petrological evidence implies that the studied vein system formed while the sample was still part of a coherent subducting slab. Rb-Sr geochronology indicates that this occurred at 38.2 ± 0.3 Ma. This age is ca. 6 myr younger than the hitherto presumed peak metamorphic
A Novel Approach for Modeling Chemical Reaction in Generalized Fluid System Simulation Program
Sozen, Mehmet; Majumdar, Alok
2002-01-01
The Generalized Fluid System Simulation Program (GFSSP) is a computer code developed at NASA Marshall Space Flight Center for analyzing steady state and transient flow rates, pressures, temperatures, and concentrations in a complex flow network. The code, which performs system level simulation, can handle compressible and incompressible flows as well as phase change and mixture thermodynamics. Thermodynamic and thermophysical property programs, GASP, WASP and GASPAK provide the necessary data for fluids such as helium, methane, neon, nitrogen, carbon monoxide, oxygen, argon, carbon dioxide, fluorine, hydrogen, water, a hydrogen, isobutane, butane, deuterium, ethane, ethylene, hydrogen sulfide, krypton, propane, xenon, several refrigerants, nitrogen trifluoride and ammonia. The program which was developed out of need for an easy to use system level simulation tool for complex flow networks, has been used for the following purposes to name a few: Space Shuttle Main Engine (SSME) High Pressure Oxidizer Turbopump Secondary Flow Circuits, Axial Thrust Balance of the Fastrac Engine Turbopump, Pressurized Propellant Feed System for the Propulsion Test Article at Stennis Space Center, X-34 Main Propulsion System, X-33 Reaction Control System and Thermal Protection System, and International Space Station Environmental Control and Life Support System design. There has been an increasing demand for implementing a combustion simulation capability into GFSSP in order to increase its system level simulation capability of a liquid rocket propulsion system starting from the propellant tanks up to the thruster nozzle for spacecraft as well as launch vehicles. The present work was undertaken for addressing this need. The chemical equilibrium equations derived from the second law of thermodynamics and the energy conservation equation derived from the first law of thermodynamics are solved simultaneously by a Newton-Raphson method. The numerical scheme was implemented as a User
Energy Technology Data Exchange (ETDEWEB)
Moller, Nancy; Weare J. H.
2008-05-29
Successful exploitation of the vast amount of heat stored beneath the earth’s surface in hydrothermal and fluid-limited, low permeability geothermal resources would greatly expand the Nation’s domestic energy inventory and thereby promote a more secure energy supply, a stronger economy and a cleaner environment. However, a major factor limiting the expanded development of current hydrothermal resources as well as the production of enhanced geothermal systems (EGS) is insufficient knowledge about the chemical processes controlling subsurface fluid flow. With funding from past grants from the DOE geothermal program and other agencies, we successfully developed advanced equation of state (EOS) and simulation technologies that accurately describe the chemistry of geothermal reservoirs and energy production processes via their free energies for wide XTP ranges. Using the specific interaction equations of Pitzer, we showed that our TEQUIL chemical models can correctly simulate behavior (e.g., mineral scaling and saturation ratios, gas break out, brine mixing effects, down hole temperatures and fluid chemical composition, spent brine incompatibilities) within the compositional range (Na-K-Ca-Cl-SO4-CO3-H2O-SiO2-CO2(g)) and temperature range (T < 350°C) associated with many current geothermal energy production sites that produce brines with temperatures below the critical point of water. The goal of research carried out under DOE grant DE-FG36-04GO14300 (10/1/2004-12/31/2007) was to expand the compositional range of our Pitzer-based TEQUIL fluid/rock interaction models to include the important aluminum and silica interactions (T < 350°C). Aluminum is the third most abundant element in the earth’s crust; and, as a constituent of aluminosilicate minerals, it is found in two thirds of the minerals in the earth’s crust. The ability to accurately characterize effects of temperature, fluid mixing and interactions between major rock-forming minerals and hydrothermal and
An Efficient Fluid-Dynamic Analysis to Improve Industrial Quenching Systems
Directory of Open Access Journals (Sweden)
Manuel de J. Barrena-Rodríguez
2017-05-01
Full Text Available This paper addresses the problem of understanding the relationship between fluid flow and heat transfer in industrial quenching systems. It also presents an efficient analysis to design or optimize long standing quenching tanks to increase productivity. The study case is automotive leaf springs quenched in an oil-tank agitated with submerged jets. This analysis combined an efficient numerical prediction of the detailed isothermal flow field in the whole tank with the thermal characterization of steel probes in plant and laboratory during quenching. These measurements were used to determine the heat flow by solving the inverse heat conduction problem. Differences between laboratory and plant heat flux results were attributed to the difference in surface area size between samples. A proposed correlation between isothermal wall shear stress and heat flux at the surface of the steel component, based on the Reynolds-Colburn analogy, provided the connection between thermal characterization and computed isothermal fluid flow. The present approach allowed the identification of the potential benefits of changes in the tank design and the evaluation of operating conditions while using a much shorter computing time and storage memory than full-domain fluid flow calculations.
A 4-DOF haptic master using ER fluid for minimally invasive surgery system application
Oh, Jong-Seok; Han, Young-Min; Lee, Sang-Rock; Choi, Seung-Bok
2013-04-01
This paper presents a novel 4-degrees-of-freedom (4-DOF) haptic master using a electrorheological (ER) fluid which is applicable to minimally invasive surgery (MIS) systems. By adopting a controllable ER fluid, the master can easily generate 4-DOF repulsive forces with the advantages of a simple mechanism and continuous force control capability. The proposed master consists of two actuators: an ER spherical joint for 3-DOF rotational motion and an ER piston device for 1-DOF translational motion. The generated torque/force models are mathematically derived by analyzing the mechanism geometry and using the Bingham characteristics of an ER Fluid. The haptic master is optimally designed and manufactured based on the mathematical torque/force models. The repulsive torque/force responses are experimentally evaluated and expressed by the first-order and second-order dynamic equations for each motion. A sliding mode controller (SMC), which is known to be robust to uncertainties, is then designed and empirically implemented to achieve the desired torque/force trajectories. It is demonstrated by presenting torque/force tracking results of both rotational and translational motions that the proposed 4-DOF ER haptic master integrated with the SMC can provide an effective haptic control performance for MIS applications.
Institute of Scientific and Technical Information of China (English)
Haisheng Liu; Zhili Ni; Yetao Chen; Dong Wang; Yan Qi; Qiuhang Zhang; Shijie Wang
2012-01-01
The present study analyzed the anatomical association between intracranial subarachnoid space and the cervical lymphatic system. X-ray contrast medium and Microfil(R) (Microfil compounds fill and opacify microvascular and other spaces of non-surviving animals and post-mortem tissue under physiological injection pressure) were injected into the cisterna magna of the rabbit, and perineural routes of cerebrospinal fluid outflow into the lymphatic system were visualized. Under a surgical operating microscope, Microfil was found within the subarachnoid space and along the olfactory nerves. At the nasal mucosa, a lymphatic network was identified near the olfactory nerves, which crossed the nasopharyngeal region and finally emptied into the superficial and deep cervical lymph nodes. Under a light microscope, Microfil was visible around the olfactory nerves and within lymphatic vessels. These results suggested that cerebrospinal fluid drained from the subarachnoid space along the olfactory nerves to nasal lymphatic vessels, which in turn, emptied into the cervical lymph nodes. This anatomical route, therefore, allowed connection between the central nervous system and the lymphatic system.
a New ER Fluid Based Haptic Actuator System for Virtual Reality
Böse, H.; Baumann, M.; Monkman, G. J.; Egersdörfer, S.; Tunayar, A.; Freimuth, H.; Ermert, H.; Khaled, W.
The concept and some steps in the development of a new actuator system which enables the haptic perception of mechanically inhomogeneous virtual objects are introduced. The system consists of a two-dimensional planar array of actuator elements containing an electrorheological (ER) fluid. When a user presses his fingers onto the surface of the actuator array, he perceives locally variable resistance forces generated by vertical pistons which slide in the ER fluid through the gaps between electrode pairs. The voltage in each actuator element can be individually controlled by a novel sophisticated switching technology based on optoelectric gallium arsenide elements. The haptic information which is represented at the actuator array can be transferred from a corresponding sensor system based on ultrasonic elastography. The combined sensor-actuator system may serve as a technology platform for various applications in virtual reality, like telemedicine where the information on the consistency of tissue of a real patient is detected by the sensor part and recorded by the actuator part at a remote location.
Binary blend of carbon dioxide and fluoro ethane as working fluid in transcritical heat pump systems
Directory of Open Access Journals (Sweden)
Zhang Xian-Ping
2015-01-01
Full Text Available As an eco-friendly working fluid, carbon dioxide or R744 is expected to substitute for the existing working fluids used in heat pump systems. It is, however, challenged by the much higher heat rejection pressure in transcritical cycle compared with the traditional subcritical cycle using freons. There exists a worldwide tendency to utilize blend refrigerants as alternatives. Therefore, a new binary blend R744/R161 in this research is proposed in order to decrease the heat rejection pressure. Meanwhile, on mixing R744 with R161, the flammability and explosivity of R161 can be suppressed because of the extinguishing effect of R744. A transcritical thermodynamic model is developed, and then the system performances of heat pump using R744/R161 blend are investigated and compared with those of pure R744 system under the same operation conditions. The variations of heat rejection pressure, heating coefficient of performance, unit volumetric heating capacity, discharge temperature of compressor and the mass fraction of R744/R161 are researched. The results show that R744/R161 mixture can reduce the heat rejection pressure of transcritical heat pump system.
Cooling Systems Design in Hot Stamping Tools by a Thermal-Fluid-Mechanical Coupled Approach
Directory of Open Access Journals (Sweden)
Tao Lin
2014-06-01
Full Text Available Hot stamping tools with cooling systems are the key facilities for hot stamping process of Ultrahigh strength steels (UHSS in automotive industry. Hot stamping tools have significant influence on the final microstructure and properties of the hot stamped parts. In serials production, the tools should be rapidly cooled by cooling water. Hence, design of hot stamping tools with cooling systems is important not only for workpieces of good quality but also for the tools with good cooling performance and long life. In this paper, a new multifield simulation method was proposed for the design of hot stamping tools with cooling system. The deformation of the tools was also analyzed by this method. Based on MpCCI (Mesh-based parallel Code Coupling Interface, thermal-fluid simulation and thermal-fluid-mechanical coupled simulation were performed. Subsequently, the geometrical parameters of the cooling system are investigated for the design. The results show that, both the distance between the ducts and the distance between the ducts and the tools loaded contour have significant influence on the quenching effect. And better quenching effect can be achieved with the shorter distance from the tool surface and with smaller distance between ducts. It is also shown that, thermal expansion is the main reason for deformation of the hot forming tools, which causes the distortion of the cooling ducts, and the stress concentration at corner of the ducts.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Based on detailed and systematic researches of the geology of ore deposits, fluid inclusions and isotope geochemistry etc., and regarding the Late Paleozoic fluid system of the Yuebei Basin as an integrated object in this paper,we have revealed the temporo-spatial evolution law of the basin's fluid system and discussed its ore-forming effects by simulating and analyzing the distribution of ore-forming elements, the fluid thermodynamics and dynamics of evolution processes of this basin. The results show that Late Paleozoic ore-forming fluid systems of the Yuebei Basin include four basic types as follows. (1) The sea floor volcanic-exhalation system developed during the rapid basin slip-extension stage in the Mid-Late Devonian, which affected the Dabaoshan region. It thus formed the Dabaoshan-type Cu-Pb-Zn-Fe sea floor volcanic-exhalation sedimentary deposits. (2) The compaction fluid system developed during the stable spreading and thermal subsidence-compression stage of the basin in the Mid-Late Devonian. The range of its effects extended all over the whole basin. It resulted in filling-metasomatic deposits, such as the Hongyan-type pyrite deposits and pyrite sheet within the Fankou-type Cu-Pb-Zn-S deposits. (3) The hot water circulation system of sea floor developed during the stage of basin uplifting and micro-aulacogen from the late Late Carboniferous to Middle Carboniferous. The range of its effects covered the Fankou region. It thus formed MVT deposits, such as the main orebody of the Fankou-type Pb-Zn-S deposits.(4) The gravity fluid system developed during the stage of fold uplifting and the basin closed from Middle Triassic to Jurassic, forming groundwater hydrothermal deposits, e.g. the veinlet Pb-Zn-calcite orebodies of the Fankou-type Pb-Zn-S deposits. Migration and concentration of the ore-forming fluids were constrained by the state of temporo-spatial distribution of its fluid potential. Growth faults not only converged the fluids and drove them to
Iron Release and Precipitation in Fracture Fluid-Shale Fracturing Systems
Jew, A. D.; Joe-Wong, C. M.; Harrison, A. L.; Thomas, D.; Dustin, M. K.; Brown, G. E.; Maher, K.; Bargar, J.
2015-12-01
Hydraulic fracturing of unconventional hydrocarbon reservoirs is important to the United States energy portfolio. Hydrocarbon production from new wells generally declines rapidly over the initial months of production. One possible reason for the decrease is the mineralization and clogging of microfracture networks proximal to propped fractures. One important but relatively unexplored class of reactions is oxidation of Fe(II) derived from Fe(II)-bearing mineral dissolution (primarily pyrite and siderite) and subsequent precipitation of Fe(III)-(oxy)hydroxides. To explore this topic, we reacted fracture fluid with sand-sized and whole rock chips from four different geological localities (Marcellus Fm., Barnett Fm., Eagle Ford Fm., and Green River Fm.) containing highly varied concentrations of clays, carbonates, and TOC. Additionally, kerogen was isolated from the Green River Fm. and reacted with fracture fluid. All the shale sands showed an initial release of Fe into solution during the first 96 hours of reaction followed by a plateau or significant drop in Fe indicating that mineral precipitation occurred. Conversely, the Fe concentrations in the kerogen reactors kept increasing throughout the 3-week experiments. The whole rock samples showed a steady increase then a plateau in Fe during the 3-weeks, indicating a slower Fe release and subsequently, slower Fe precipitation. Reactors with Marcellus Fm. Sands contained dilute HCl, water only, the fracture fluid with no headspace, and fracture fluid with no HCl. Results from these experiments show that HCl is the most important additive for the promotion of Fe release into solution. Iron oxidation is not promoted solely by O2 or organics but instead requires a combination of the two for precipitation in these systems. These results indicate that Fe redox cycling is an important and complex part of hydraulic fracturing that most likely results in production slowdown over the life of a well.
Directory of Open Access Journals (Sweden)
Degtyarev Alexander
2016-01-01
Full Text Available The paper deals with the computer implementation of direct computational experiments in fluid mechanics, constructed on the basis of the approach developed by the authors. The proposed approach allows the use of explicit numerical scheme, which is an important condition for increasing the effciency of the algorithms developed by numerical procedures with natural parallelism. The paper examines the main objects and operations that let you manage computational experiments and monitor the status of the computation process. Special attention is given to a realization of tensor representations of numerical schemes for direct simulation; b realization of representation of large particles of a continuous medium motion in two coordinate systems (global and mobile; c computing operations in the projections of coordinate systems, direct and inverse transformation in these systems. Particular attention is paid to the use of hardware and software of modern computer systems.
Chen, Liwen; Chi, Wu-Cheng; Lin, Yu-Hsieh; Berndt, Christian; Lin, Saulwood
2016-04-01
Four-Way-Closure (4WC) Ridge shows great potential as a hydrate prospect from collected multitude of marine geophysical datasets offshore southwestern Taiwan. The aim of my study is to better understand the fluid migration patterns and the possible source locations of the methane at this site. It is a cold seep site with an elongated NW-SE trending anticlinal ridge, which is formed by fault-related folds in the frontal segment of the lower slope domain of the Taiwan accretionary prism along its convergent boundary. So I detail recognized the regional feature structures of the 4WC Ridge, including the thrust faulting and a seismic chimney beneath the seepage sites. I plan to study the temperature perturbation at the 4WC Ridge to better understand gas hydrate system there. To quantify the amount of temperature perturbation near the fault zone, we need to correct the temperature field data for other geological processes. One important correction we want to make concerns the topographic effects on the shallow crust temperature field. So we used 3D finite element method to quantify how much temperature perturbation can be attributed to the local bathymetry at the 4WC Ridge. This model will give us a temperature field based on pure thermal conduction. Then, we can compare the model temperature field with the temperature field derived from thousands of BSRs from the seismic cube, and interpret any resulting temperature discrepancy. As our previous study, we known several geological processes can cause such a discrepancy, including advective fluid migration. If the fault zone fluid migration hypothesis is correct and gas hydrate system reacts to the deep warm fluids from below it, we expect that the BSR will become shallower near the fluid pathways, and the BSR-based temperature field might be a few degrees Celsius higher than in the 3D thermal conductive temperature field. Otherwise, the two temperature fields should be similar. This study is important for hydrate
Fault and fluid systems in supra-subduction zones: The Troodos ophiolite
Quandt, Dennis; Micheuz, Peter; Kurz, Walter; Krenn, Kurt
2017-04-01
The Troodos massif on the island of Cyprus represents a well-preserved and complete supra-subduction zone (SSZ) ophiolite. It includes an extrusive sequence that is subdivided into Upper (UPL) and Lower Pillow Lavas (LPL). These volcanic rocks contain mineralized fractures (veins) and vesicles that record fluid availability probably related to slab dehydration and deformation subsequent to a period of subduction initiation in the framework of a SSZ setting. Here, we present electron microprobe element mappings and cathodoluminescence studies of vein minerals as well as analyses of fluid inclusions entrapped in zeolite, calcite and quartz from veins and vesicles of the Pillow Lavas of the Troodos ophiolite. Two different zeolite type assemblages, interpreted as alteration products of compositional varying volcanic glasses, occur: (1) Na-zeolites analcime and natrolite from the UPL that require lower formation temperatures, higher Na/Ca ratios and pH values than (2) Ca-zeolites heulandite and mordenite from the LPL which indicate temporal or spatial varying fluid compositions and conditions. Calcite represents a late stage phase in incompletely sealed blocky type (1) assemblage and in syntaxial quartz veins. Additionally, calcite occurs as major phase in syntaxial and blocky veins of UPL and LPL. These syntaxial quartz and calcite veins are assumed to be related to tectonic extension. Chalcedony is associated with quartz and occurs in typical veins and vesicles of the LPL. In addition, the presence of neptunian dykes in veins suggests that seawater penetrated fractures throughout the extrusive sequence. Thus, circulation in an open system via advective transport is favored while diffusion in a closed system is a subordinate, local and late stage phenomenon. Calcite veins and quartz vesicles contain primary, partly re-equilibrated two phase (liquid, vapor) fluid inclusions. The chemical system of all studied inclusions in both host minerals is restricted to aqueous
Directory of Open Access Journals (Sweden)
Kai Yang
2014-08-01
Full Text Available One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction, the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF, waste heat recovery efficiency (WHRE, and engine thermal efficiency increasing ratio (ETEIR all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.
Energy Technology Data Exchange (ETDEWEB)
Tanaka, Y. [Hosei University, Tokyo (Japan). Faculty of Engineering
2000-01-15
This paper describes the human-machine cooperative system and fluid power technology. Most of Japanese robot R and D activities shifted from early R and D on hydraulic or pneumatic driving to that on simple electric driving, and development of fluid power technology as actuator and control technology is retarded. For creating an artificial work environment with a presence by virtual reality formation technology, an equipment (actuator) directly acting such five senses (sensor) of operators as visual, auditory, pressure and contact senses is essential. Pneumatic actuator is extremely suitable for such one because of its small size, light weight, safety and high power density. Robocup has been held as the soccer game of many autonomous robots. For the soccer game of human beings and robots, development of such technologies for advanced autonomous robots is necessary as realtime processing, advanced intelligence, human friendliness, safety, high-efficiency high-power actuator equivalent to human muscle, and energy source. (NEDO)
MODELING OF MESO-SCALE STRUCTURES IN PARTICLE-FLUID SYSTEMS: THE EMMS/CFD APPROACH
Institute of Scientific and Technical Information of China (English)
Ning Yang; Wei Wang; Wei Ge; Jinghai Li
2005-01-01
Meso-scale structures existing in the form of particle-rich clusters, streamers or strands in circulating fluidized beds, and of ascending bubble plumes and descending liquid-rich vortices in bubble columns and slurry-bed reactors, as commonly observed, have played an important role in the macro-scale behavior of particle-fluid systems. These meso-scale structures span a wide range of length and time scales, and their origin, evolution and influence are still far from being well understood.Recent decades have witnessed the emergence of computer simulation of particle-fluid systems based on computational fluid dynamic (CFD) models. However, strictly speaking these models are far from mature and the complex nature of particle-fluid systems arising from the meso-scale structures has been posing great challenges to investigators. The reason may be that the current two-fluid models (TFM) are derived either from continuum mechanics by using different kinds of averaging techniques for the conservation equations of single-phase flow, or from the kinetic theory of gases in which the assumption of molecular chaos is employed, thereby losing sight of the meso-scale heterogeneity at the scale of computational cells and leading to inaccurate calculation of the interaction force between particles and fluids. For example, the overall drag force for particles in a cell is usually calculated from the empirical Wen & Yu/Ergun correlations,which should be suspected since these correlations were originally derived from homogeneous systems.Schemes to solve this problem for gas-particles systems may be classified into four categories. First, one could capture the detailed meso-scale structure information at the cell scale by employing the so-called direct numerical simulation (DNS) (Hu, 1996), the pseudo-particle modeling (PPM) (Ge & Li, 2003), or the Lattice-Boltzmann method (LBM) to track the interface between gas and particles. Second, refinement of the computational meshes may
Research and application of non-clay low damage temporary bridging drilling/completion fluids system
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate (CaCO3) particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drillin...
A transient thermal model of a neutral buoyancy cryogenic fluid delivery system
Bue, Grant C.; Conger, Bruce S.
A thermal-performance model is presently used to evaluate a preliminary Neutral Buoyancy Cryogenic fluid-delivery system for underwater EVA training. Attention is given to the modeling of positional transients generated from the moving of internal components, including the control of cycling artifacts, as well as to the convection and boiling characteristics of the cryofluid, 250-psi N2/O2 gas, and water contained in the tank. Two piston designs are considered according to performance criteria; temperature and heat-transfer rate profiles are presented.
Reliability Based Design of Fluid Power Pitch Systems for Wind Turbines
DEFF Research Database (Denmark)
Liniger, Jesper; N. Soltani, Mohsen; Pedersen, Henrik Clemmensen
2017-01-01
in a case study of a fluid power pitch system applied to wind turbines. The results show a good agreement to recent field failure data for offshore turbines where the dominating failure modes are related to valves, accumulators and leakage. The results are further used for making design improvements...... Priority Number. The Failure Mode and Effect Criticality Analysis is based on past research concerning failure analysis of wind turbine drive trains. Guidelines are given to select the severity, occurrence and detection score that make up the risk priority number. The usability of the method is shown...
A Post-Newtonian approach to black hole-fluid systems
Barausse, Enrico
2013-01-01
This work devises a formalism to obtain the equations of motion for a black hole-fluid configuration. Our approach is based on a Post-Newtonian expansion and adapted to scenarios where obtaining the relevant dynamics requires long time-scale evolutions. These systems are typically studied with Newtonian approaches, which have the advantage that larger time-steps can be employed than in full general-relativistic simulations, but have the downside that important physical effects are not accounted for. The formalism presented here provides a relatively straightforward way to incorporate those effects in existing implementations, up to 2.5PN order, with lower computational costs than fully relativistic simulations.
DEFF Research Database (Denmark)
Ostergaard, Christian; Benfield, Thomas
2009-01-01
ABSTRACT: INTRODUCTION: Macrophage Migration Inhibitory Factor (MIF) plays an essential pathophysiological role in septic shock; however, its role in central nervous system infection (CNS) remains to be defined. METHODS: The aim of the present study was to investigate cerebrospinal fluid (CSF...... suspected of but had no evidence of CNS infection. RESULTS: CSF MIF levels were significantly higher in patients with purulent meningitis of known aetiology (8639 ng/L (3344-20600)) as compared to patients with purulent meningitis of unknown aetiology (2209 ng/L (1516-6550), Mann Whitney test, P=0...
Reprogramming of mouse amniotic fluid cells using a PiggyBac transposon system
Directory of Open Access Journals (Sweden)
E. Bertin
2015-11-01
Full Text Available Induced pluripotent stem (iPS cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using different methods. Amniotic fluid (AF cells are easy to obtain from routinely scheduled procedures for prenatal diagnosis and iPS cells have been generated from human AF. Here, we generated iPS cells from mouse AF cells, using a non-viral-based approach constituted by the PiggyBac (PB transposon system. All iPS cell lines obtained exhibited characteristics of pluripotent cells, including the ability to differentiate toward derivatives of all three germ layers in vitro and in vivo.