Energy transport in cooling device by magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Hiroshi, E-mail: hyamaguc@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyo-tanabe, Kyoto 610-0321 (Japan); Iwamoto, Yuhiro [Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555 (Japan)

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

Energy transport in cooling device by magnetic fluid

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-01-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

KM3NeT tower data acquisition and data transport electronics

Science.gov (United States)

Nicolau, C. A.; Ameli, F.; Biagioni, A.; Capone, A.; Frezza, O.; Lonardo, A.; Masullo, R.; Mollo, C. M.; Orlando, A.; Simeone, F.; Vicini, P.

2016-04-01

In the framework of the KM3Net European project, the production stage of a large volume underwater neutrino telescope has started. The forthcoming installation includes 8 towers and 24 strings, that will be installed 100 km off-shore Capo Passero (Italy) at 3500 m depth. The KM3NeT tower, whose layout is strongly based on the NEMO Phase-2 prototype tower deployed in March 2013, has been re-engineered and partially re-designed in order to optimize production costs, power consumption, and usability. This contribution gives a description of the main electronics, including front-end, data transport and clock distribution system, of the KM3NeT tower detection unit.

NeMO-Net & Fluid Lensing: The Neural Multi-Modal Observation & Training Network for Global Coral Reef Assessment Using Fluid Lensing Augmentation of NASA EOS Data

Science.gov (United States)

Chirayath, Ved

2018-01-01

We present preliminary results from NASA NeMO-Net, the first neural multi-modal observation and training network for global coral reef assessment. NeMO-Net is an open-source deep convolutional neural network (CNN) and interactive active learning training software in development which will assess the present and past dynamics of coral reef ecosystems. NeMO-Net exploits active learning and data fusion of mm-scale remotely sensed 3D images of coral reefs captured using fluid lensing with the NASA FluidCam instrument, presently the highest-resolution remote sensing benthic imaging technology capable of removing ocean wave distortion, as well as hyperspectral airborne remote sensing data from the ongoing NASA CORAL mission and lower-resolution satellite data to determine coral reef ecosystem makeup globally at unprecedented spatial and temporal scales. Aquatic ecosystems, particularly coral reefs, remain quantitatively misrepresented by low-resolution remote sensing as a result of refractive distortion from ocean waves, optical attenuation, and remoteness. Machine learning classification of coral reefs using FluidCam mm-scale 3D data show that present satellite and airborne remote sensing techniques poorly characterize coral reef percent living cover, morphology type, and species breakdown at the mm, cm, and meter scales. Indeed, current global assessments of coral reef cover and morphology classification based on km-scale satellite data alone can suffer from segmentation errors greater than 40%, capable of change detection only on yearly temporal scales and decameter spatial scales, significantly hindering our understanding of patterns and processes in marine biodiversity at a time when these ecosystems are experiencing unprecedented anthropogenic pressures, ocean acidification, and sea surface temperature rise. NeMO-Net leverages our augmented machine learning algorithm that demonstrates data fusion of regional FluidCam (mm, cm-scale) airborne remote sensing with

Energy transport in cooling device by magnetic fluid

Science.gov (United States)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering.

KM3NeT tower data acquisition and data transport electronics

Directory of Open Access Journals (Sweden)

Nicolau C.A.

2016-01-01

Full Text Available In the framework of the KM3Net European project, the production stage of a large volume underwater neutrino telescope has started. The forthcoming installation includes 8 towers and 24 strings, that will be installed 100 km off-shore Capo Passero (Italy at 3500 m depth. The KM3NeT tower, whose layout is strongly based on the NEMO Phase-2 prototype tower deployed in March 2013, has been re-engineered and partially re-designed in order to optimize production costs, power consumption, and usability. This contribution gives a description of the main electronics, including front-end, data transport and clock distribution system, of the KM3NeT tower detection unit.

Fluid/Gravity Correspondence, Second Order Transport and Gravitational Anomaly*,**

Directory of Open Access Journals (Sweden)

Megías Eugenio

2014-03-01

Full Text Available We study the transport properties of a relativistic fluid affected by chiral and gauge-gravitational anomalies. The computation is performed in the framework of the fluid/gravity correspondence for a 5 dim holographic model with Chern-Simons terms in the action. We find new anomalous and non anomalous transport coefficients, as well as new contributions to the existing ones coming from the mixed gauge-gravitational anomaly. Consequences for the shear waves dispersion relation are analyzed.

Peritoneal Fluid Transport rather than Peritoneal Solute Transport Associates with Dialysis Vintage and Age of Peritoneal Dialysis Patients

Directory of Open Access Journals (Sweden)

Jacek Waniewski

2016-01-01

Full Text Available During peritoneal dialysis (PD, the peritoneal membrane undergoes ageing processes that affect its function. Here we analyzed associations of patient age and dialysis vintage with parameters of peritoneal transport of fluid and solutes, directly measured and estimated based on the pore model, for individual patients. Thirty-three patients (15 females; age 60 (21–87 years; median time on PD 19 (3–100 months underwent sequential peritoneal equilibration test. Dialysis vintage and patient age did not correlate. Estimation of parameters of the two-pore model of peritoneal transport was performed. The estimated fluid transport parameters, including hydraulic permeability (LpS, fraction of ultrasmall pores (αu, osmotic conductance for glucose (OCG, and peritoneal absorption, were generally independent of solute transport parameters (diffusive mass transport parameters. Fluid transport parameters correlated whereas transport parameters for small solutes and proteins did not correlate with dialysis vintage and patient age. Although LpS and OCG were lower for older patients and those with long dialysis vintage, αu was higher. Thus, fluid transport parameters—rather than solute transport parameters—are linked to dialysis vintage and patient age and should therefore be included when monitoring processes linked to ageing of the peritoneal membrane.

Peritoneal Fluid Transport rather than Peritoneal Solute Transport Associates with Dialysis Vintage and Age of Peritoneal Dialysis Patients

Science.gov (United States)

Waniewski, Jacek; Antosiewicz, Stefan; Baczynski, Daniel; Poleszczuk, Jan; Pietribiasi, Mauro; Lindholm, Bengt; Wankowicz, Zofia

2016-01-01

During peritoneal dialysis (PD), the peritoneal membrane undergoes ageing processes that affect its function. Here we analyzed associations of patient age and dialysis vintage with parameters of peritoneal transport of fluid and solutes, directly measured and estimated based on the pore model, for individual patients. Thirty-three patients (15 females; age 60 (21–87) years; median time on PD 19 (3–100) months) underwent sequential peritoneal equilibration test. Dialysis vintage and patient age did not correlate. Estimation of parameters of the two-pore model of peritoneal transport was performed. The estimated fluid transport parameters, including hydraulic permeability (LpS), fraction of ultrasmall pores (α u), osmotic conductance for glucose (OCG), and peritoneal absorption, were generally independent of solute transport parameters (diffusive mass transport parameters). Fluid transport parameters correlated whereas transport parameters for small solutes and proteins did not correlate with dialysis vintage and patient age. Although LpS and OCG were lower for older patients and those with long dialysis vintage, αu was higher. Thus, fluid transport parameters—rather than solute transport parameters—are linked to dialysis vintage and patient age and should therefore be included when monitoring processes linked to ageing of the peritoneal membrane. PMID:26989432

Neutron transport assembly calculation with non-zero net current boundary condition

International Nuclear Information System (INIS)

Jo, Chang Keun

1993-02-01

Fuel assembly calculation for the homogenized group constants is one of the most important parts in the reactor core analysis. The homogenized group constants of one a quarter assembly are usually generated for the nodal calculation of the reactor core. In the current nodal calculation, one or a quarter of the fuel assembly corresponds to a unit node. The homogenized group constant calculation for a fuel assembly proceeds through cell spectrum calculations, group condensation and cell homogenization calculations, two dimensional fuel assembly calculation, and then depletion calculations of fuel rods. To obtain the assembly wise homogenized group constants, the two dimensional transport calculation is usually performed. Most codes for the assembly wise homogenized group constants employ a zero net current boundary condition. CASMO-3 is such a code that is in wide use. The zero net current boundary condition is plausible and valid in an infinite reactor composed of the same kind of assemblies. However, the reactor is finite and the core is constructed by different kinds of assemblies. Hence, the assumption of the zero net current boundary condition is not valid in the actual reactor. The objective of this study is to develop a homogenization methodology that can treat any actual boundary condition, i.e. non-zero net current boundary condition. In order to treat the non-zero net current boundary condition, we modify CASMO-3. For the two-dimensional treatment in CASMO-3, a multigroup integral transport routine based on the method of transmission probability is used. The code performs assembly calculation with zero net current boundary condition. CASMO-3 is modified to consider the inhomogeneous source at the assembly boundary surface due to the non-zero net current. The modified version of CASMO-3 is called CASMO-3M. CASMO-3M is applied to several benchmark problems. In order to obtain the inhomogeneous source, the global calculation is performed. The local calculation

Lagrangian transport characteristics of a class of three-dimensional inline-mixing flows with fluid inertia

International Nuclear Information System (INIS)

Speetjens, M. F. M.; Demissie, E. A.; Metcalfe, G.; Clercx, H. J. H.

2014-01-01

Laminar mixing by the inline-mixing principle is a key to many industrial fluids-engineering systems of size extending from micrometers to meters. However, insight into fundamental transport phenomena particularly under the realistic conditions of three-dimensionality (3D) and fluid inertia remains limited. This study addresses these issues for inline mixers with cylindrical geometries and adopts the Rotated Arc Mixer (RAM) as a representative system. Transport is investigated from a Lagrangian perspective by identifying and examining coherent structures that form in the 3D streamline portrait. 3D effects and fluid inertia introduce three key features that are not found in simplified configurations: transition zones between consecutive mixing cells of the inline-mixing flow; local upstream flow (in certain parameter regimes); transition/inertia-induced breaking of symmetries in the Lagrangian equations of motion (causing topological changes in coherent structures). Topological considerations strongly suggest that there nonetheless always exists a net throughflow region between inlet and outlet of the inline-mixing flow that is strictly separated from possible internal regions. The Lagrangian dynamics in this region admits representation by a 2D time-periodic Hamiltonian system. This establishes one fundamental kinematic structure for the present class of inline-mixing flows and implies universal behavior in that all states follow from the Hamiltonian breakdown of one common integrable state. A so-called period-doubling bifurcation is the only way to eliminate transport barriers originating from this state and thus is a necessary (yet not sufficient) condition for global chaos. Important in a practical context is that a common simplification in literature, i.e., cell-wise fully-developed Stokes flow (“2.5D approach”), retains these fundamental kinematic properties and deviates from the generic 3D inertial case only in a quantitative sense. This substantiates its

Magnetic method for stimulating transport in fluids

Science.gov (United States)

Martin, James E.; Solis, Kyle J.

2016-10-18

A method for producing mass and heat transport in fluids, wherein the method does not rely on conventional convection, that is, it does not require gravity, a thermal gradient, or a magnetic field gradient. This method gives rise to a unique class of vigorous, field-controllable flow patterns termed advection lattices. The advection lattices can be used to transport heat and/or mass in any desired direction using only magnetic fields.

Turbulent transport across invariant canonical flux surfaces

International Nuclear Information System (INIS)

Hollenberg, J.B.; Callen, J.D.

1994-07-01

Net transport due to a combination of Coulomb collisions and turbulence effects in a plasma is investigated using a fluid moment description that allows for kinetic and nonlinear effects via closure relations. The model considered allows for ''ideal'' turbulent fluctuations that distort but preserve the topology of species-dependent canonical flux surfaces ψ number-sign,s triple-bond ∫ dF · B number-sign,s triple-bond ∇ x [A + (m s /q s )u s ] in which u s is the flow velocity of the fluid species. Equations for the net transport relative to these surfaces due to ''nonideal'' dissipative processes are found for the total number of particles and total entropy enclosed by a moving canonical flux surface. The corresponding particle transport flux is calculated using a toroidal axisymmetry approximation of the ideal surfaces. The resulting Lagrangian transport flux includes classical, neoclassical-like, and anomalous contributions and shows for the first time how these various contributions should be summed to obtain the total particle transport flux

Prediction of transport and other physical properties of fluids

CERN Document Server

Bretsznajder, S

1971-01-01

Prediction of Transport and Other Physical Properties of Fluids reviews general methods for predicting the transport and other physical properties of fluids such as gases and liquids. Topics covered range from the theory of corresponding states and methods for estimating the surface tension of liquids to some basic concepts of the kinetic theory of gases. Methods of estimating liquid viscosity based on the principle of additivity are also described. This volume is comprised of eight chapters and opens by presenting basic information on gases and liquids as well as intermolecular forces and con

Fluid transportation mechanisms by a coupled system of elastic membranes and magnetic fluids

International Nuclear Information System (INIS)

Ido, Y.; Tanaka, K.; Sugiura, Y.

2002-01-01

The basic properties of the fluid transportation mechanism that is produced by the coupled waves propagating along a thin elastic membrane covering a magnetic fluid layer in a shallow and long rectangular vessel are investigated. It is shown that the progressive magnetic field induced by the rectangular pulses generates sinusoidal vibration of the displacement of elastic membrane and makes the system work more efficiently than the magnetic field induced by the pulse-width-modulation method

A Bingham-plastic model for fluid mud transport under waves and currents

Science.gov (United States)

Liu, Chun-rong; Wu, Bo; Huhe, Ao-de

2014-04-01

Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations which are solved by hybrid numerical-analytical technique. As the computational cost is very low, the effects of wave current parameters and fluid mud properties on the transportation velocity of the fluid mud are studied systematically. It is found that the fluid mud can move toward one direction even if the shear stress acting on the fluid mud bed is much smaller than the fluid mud yield stress under the condition of wave and current coexistence. Experiments of the fluid mud motion under current with fluctuation water surface are carried out. The fluid mud transportation velocity predicted by the presented mathematical model can roughly match that measured in experiments.

Numerical modelling of cuttings transport in horizontal wells using conventional drilling fluids

Energy Technology Data Exchange (ETDEWEB)

Li, Y.; Bjorndalen, E.; Kuru, E. [Alberta Univ., Edmonton, AB (Canada)

2004-07-01

Some of the problems associated with poor wellbore cleaning include high drag or torque, slower rate of penetration, formation fractures and difficulty in wellbore steering. Some of the factors that affect cuttings transport include drilling fluid velocity, inclination angle, drilling fluid viscosity and drilling rate. The general practice is to stop drilling when necessary to clean boreholes with viscous pills, pipe rotation or drilling fluid circulation. It is important to predict when drilling should be stopped for remedial wellbore cleaning. This can be accomplished with a transient cuttings transport model which can improve drilling hydraulics, particularly in long horizontal well sections and extended reach (ERD) wells. This paper presents a newly developed 1-dimensional transient mechanistic model of cuttings transport with conventional (incompressible) drilling fluids in horizontal wells. The numerically solved model predicts the height of cutting beds as a function of different drilling operational parameters such as fluid flow rate and rheological characteristics, drilling rates, wellbore geometry and drillpipe eccentricity. Sensitivity analysis has demonstrated the effects of these parameters on the efficiency of solids transport. The proposed model can be used in the creation of computer programs designed to optimize drilling fluid rheology and flow rates for horizontal well drilling. 29 refs., 3 tabs., 12 figs.

Peristaltic transport and mixing of cytosol through the whole body of Physarum plasmodium.

Science.gov (United States)

Iima, Makoto; Nakagaki, Toshiyuki

2012-09-01

We study how the net transport and mixing of chemicals occur in a relatively large amoeba, the true slime mold Physarum polycephalum. The shuttle streaming of the amoeba is characterized by a rhythmic flow of the order of 1 μm/s in which the protoplasm streams back and forth. To explain the experimentally observed transport of chemicals, we formulate a simplified model to consider the mechanism by which net transport can be induced by shuttle (or periodic) motion inside the amoeba. This model is independent from the details of fluid property as it is based on the mass conservation law only. Even in such a simplified model, we demonstrate that sectional oscillations play an important role in net transport and discuss the effects of the sectional boundary motion on net transport in the microorganism.

Geographic information systems - transportation ISTEA management systems server net prototype pooled fund study : phase B - summary

Science.gov (United States)

1997-06-01

The Geographic Information System-Transportation (GIS-T) ISTEA Management Systems Server Net Prototype Pooled Fund Study represents the first national cooperative effort in the transportation industry to address the management and monitoring systems ...

Assessment of the Electrification of the Road Transport Sector on Net System Emissions

Science.gov (United States)

Miller, James

As worldwide environmental consciousness grows, electric vehicles (EVs) are becoming more common and despite the incredible potential for emissions reduction, the net emissions of the power system supply side plus the transportation system are dependent on the generation matrix. Current EV charging patterns tend to correspond directly with the peak consumption hours and have the potential to increase demand sharply allowing for only a small penetration of Electric Vehicles. Using the National Household Travel Survey (NHTS) data a model is created for vehicle travel patterns using trip chaining. Charging schemes are modeled to include uncontrolled residential, uncontrolled residential/industrial charging, optimized charging and optimized charging with vehicle to grid discharging. A charging profile is then determined based upon the assumption that electric vehicles would directly replace a percentage of standard petroleum-fueled vehicles in a known system. Using the generation profile for the specified region, a unit commitment model is created to establish not only the generation dispatch, but also the net CO2 profile for variable EV penetrations and charging profiles. This model is then used to assess the impact of the electrification of the road transport sector on the system net emissions.

Collisional transport across the magnetic field in drift-fluid models

DEFF Research Database (Denmark)

Madsen, Jens; Naulin, Volker; Nielsen, Anders Henry

2016-01-01

Drift ordered fluid models are widely applied in studies of low-frequency turbulence in the edge and scrape-off layer regions of magnetically confined plasmas. Here, we show how collisional transport across the magnetic field is self-consistently incorporated into drift-fluid models without...

Net-baryon-, net-proton-, and net-charge kurtosis in heavy-ion collisions within a relativistic transport approach

International Nuclear Information System (INIS)

Nahrgang, Marlene; Schuster, Tim; Stock, Reinhard; Mitrovski, Michael; Bleicher, Marcus

2012-01-01

We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand-canonical ensemble we explicitly take into account exact electric and baryon charge conservation on an event-by-event basis. This drastically limits the width of baryon fluctuations. A simple model to account for this is to assume a grand-canonical distribution with a sharp cut-off at the tails. We present baseline predictions of the energy dependence of the net-baryon, net-proton and net-charge kurtosis for central (b≤2.75 fm) Pb+Pb/Au+Au collisions from E lab =2A GeV to √(s NN )=200 GeV from the UrQMD model. While the net-charge kurtosis is compatible with values around zero, the net-baryon number decreases to large negative values with decreasing beam energy. The net-proton kurtosis becomes only slightly negative for low √(s NN ). (orig.)

Computer program for calculating thermodynamic and transport properties of fluids

Science.gov (United States)

Hendricks, R. C.; Braon, A. K.; Peller, I. C.

1975-01-01

Computer code has been developed to provide thermodynamic and transport properties of liquid argon, carbon dioxide, carbon monoxide, fluorine, helium, methane, neon, nitrogen, oxygen, and parahydrogen. Equation of state and transport coefficients are updated and other fluids added as new material becomes available.

Fluid flow and convective transport of solutes within the intervertebral disc

NARCIS (Netherlands)

Ferguson, S.J.; Ito, K.; Nolte, L.P.

2004-01-01

Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport

Modeling interfacial area transport in multi-fluid systems

Energy Technology Data Exchange (ETDEWEB)

Yarbro, Stephen Lee [Univ. of California, Berkeley, CA (United States)

1996-11-01

Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacial area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.

Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

OpenAIRE

Misra, J. C.; Maiti, S.

2011-01-01

Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bo...

A new method to describe two-phase solvent extraction based on net transport potential derived as linear combinations of forward and reverse constituents

International Nuclear Information System (INIS)

Nabeshima, Masahiro

1998-01-01

With the view to avoiding the difficulties encountered in estimating thermodynamic activities of the multiple chemical species in two-phase liquid system, a set of forward, reverse, net and total transport potentials are defined to represent the chemical state of a transferring solute during transient using bulk concentrations. The net transport potential corresponds to that in the conventional two-film model of diffusion-controlled processes. The overall driving forces of mass transport are redefined as the derivatives of the relevant transport potentials differentiated with respect to a state variable newly defined in terms of the bulk concentrations of the solute contained in both phases. Net and total quantities, i.e. transport potentials, overall driving forces and the molar fluxes are obtained as linear combinations of those for forward and reverse directions. The topical features presented by these quantities and their mutual relations are discussed in detail. The experimental new overall transport coefficient for U(VI) varied in accord with the changes in the theoretical net transport potential and overall driving force. The present method permits describing the extractive mass transport consistently both to forward and reverse directions of transport. (author)

Development of a numerical model for fluid-structure interaction analysis of flow through and around an aquaculture net cage

DEFF Research Database (Denmark)

Chen, Hao; Christensen, Erik Damgaard

2017-01-01

In the present work, we developed a numerical model for fluid-structure interaction analysis of flow through and around an aquaculture net cage. The numerical model is based on the coupling between the porous media model and the lumped mass structural model. A novel interface was implemented...

Extended fluid transport theory in the tokamak plasma edge

Science.gov (United States)

Stacey, W. M.

2017-06-01

Fluid theory expressions for the radial particle and energy fluxes and the radial distributions of pressure and temperature in the edge plasma are derived from fundamental conservation (particle, energy, momentum) relations, taking into account kinetic corrections arising from ion orbit loss, and integrated to illustrate the dependence of the observed edge pedestal profile structure on fueling, heating, and electromagnetic and thermodynamic forces. Solution procedures for the fluid plasma and associated neutral transport equations are discussed.

Cerebrospinal Fluid and Interstitial Fluid Motion via the Glymphatic Pathway Modelled by Optimal Mass Transport

OpenAIRE

Benveniste, Helene; Nedergaard, Maikan; Lee, Hedok; Gao, Yi; Tannenbaum, Allen; Ratner, Vadim

2016-01-01

It was recently shown that the brain-wide cerebrospinal fluid (CSF) and interstitial fluid exchange system designated the `glymphatic pathway' plays a key role in removing waste products from the brain, similarly to the lymphatic system in other body organs [1,2]. It is therefore important to study the flow patterns of glymphatic transport through the live brain in order to better understand its functionality in normal and pathological states. Unlike blood, the CSF does not flow rapidly throu...

Functional resistance of enamel and the phenomenon of transtegumental fluid transport

Directory of Open Access Journals (Sweden)

Okushko V.R. Okushko R.V. Ursan R.V.

2011-03-01

Full Text Available Current data related to transport of fluid through the covering tissue formations (skin, nail plate, dental enamel, gum valley are being analyzed. A supposition is made of transtegumental fluid transport (TFT as a general biological regularity which is specifically manifested in tissues of different functional purposes. Depending on the peculiarity of the organ, the tooth performs the TFT providing functional resistance of the enamel, whose level is clinically detected in the «test of enamel resistance» (TER used in modern research. The article draws attention to the reasonability of an in-depth study of the tooth physiology, where the central element is TFT. This phenomenon is of interest both from fundamental and highly practical standpoints. Identification of seasonal periods in the functional resistance decline makes it possible to get a distinct effect by means of concentrating prevention efforts on this. The TER sample, as well as other transtegumental fluid transport patterns, is to find place in the system of personalized predictive approach to caries diseases

Fully multidimensional flux-corrected transport algorithms for fluids

International Nuclear Information System (INIS)

Zalesak, S.T.

1979-01-01

The theory of flux-corrected transport (FCT) developed by Boris and Book is placed in a simple, generalized format, and a new algorithm for implementing the critical flux limiting stage in multidimensions without resort to time splitting is presented. The new flux limiting algorithm allows the use of FCT techniques in multidimensional fluid problems for which time splitting would produce unacceptable numerical results, such as those involving incompressible or nearly incompressible flow fields. The 'clipping' problem associated with the original one dimensional flux limiter is also eliminated or alleviated. Test results and applications to a two dimensional fluid plasma problem are presented

Space-Time Dependent Transport, Activation, and Dose Rates for Radioactivated Fluids.

Science.gov (United States)

Gavazza, Sergio

Two methods are developed to calculate the space - and time-dependent mass transport of radionuclides, their production and decay, and the associated dose rates generated from the radioactivated fluids flowing through pipes. The work couples space- and time-dependent phenomena, treated as only space- or time-dependent in the open literature. The transport and activation methodology (TAM) is used to numerically calculate space- and time-dependent transport and activation of radionuclides in fluids flowing through pipes exposed to radiation fields, and volumetric radioactive sources created by radionuclide motions. The computer program Radionuclide Activation and Transport in Pipe (RNATPA1) performs the numerical calculations required in TAM. The gamma ray dose methodology (GAM) is used to numerically calculate space- and time-dependent gamma ray dose equivalent rates from the volumetric radioactive sources determined by TAM. The computer program Gamma Ray Dose Equivalent Rate (GRDOSER) performs the numerical calculations required in GAM. The scope of conditions considered by TAM and GAM herein include (a) laminar flow in straight pipe, (b)recirculating flow schemes, (c) time-independent fluid velocity distributions, (d) space-dependent monoenergetic neutron flux distribution, (e) space- and time-dependent activation process of a single parent nuclide and transport and decay of a single daughter radionuclide, and (f) assessment of space- and time-dependent gamma ray dose rates, outside the pipe, generated by the space- and time-dependent source term distributions inside of it. The methodologies, however, can be easily extended to include all the situations of interest for solving the phenomena addressed in this dissertation. A comparison is made from results obtained by the described calculational procedures with analytical expressions. The physics of the problems addressed by the new technique and the increased accuracy versus non -space and time-dependent methods

Estimates of Lagrangian particle transport by wave groups: forward transport by Stokes drift and backward transport by the return flow

Science.gov (United States)

van den Bremer, Ton S.; Taylor, Paul H.

2014-11-01

Although the literature has examined Stokes drift, the net Lagrangian transport by particles due to of surface gravity waves, in great detail, the motion of fluid particles transported by surface gravity wave groups has received considerably less attention. In practice nevertheless, the wave field on the open sea often has a group-like structure. The motion of particles is different, as particles at sufficient depth are transported backwards by the Eulerian return current that was first described by Longuet-Higgins & Stewart (1962) and forms an inseparable counterpart of Stokes drift for wave groups ensuring the (irrotational) mass balance holds. We use WKB theory to study the variation of the Lagrangian transport by the return current with depth distinguishing two-dimensional seas, three-dimensional seas, infinite depth and finite depth. We then provide dimensional estimates of the net horizontal Lagrangian transport by the Stokes drift on the one hand and the return flow on the other hand for realistic sea states in all four cases. Finally we propose a simple scaling relationship for the transition depth: the depth above which Lagrangian particles are transported forwards by the Stokes drift and below which such particles are transported backwards by the return current.

Modified two-fluid model for the two-group interfacial area transport equation

International Nuclear Information System (INIS)

Sun Xiaodong; Ishii, Mamoru; Kelly, Joseph M.

2003-01-01

This paper presents a modified two-fluid model that is ready to be applied in the approach of the two-group interfacial area transport equation. The two-group interfacial area transport equation was developed to provide a mechanistic constitutive relation for the interfacial area concentration in the two-fluid model. In the two-group transport equation, bubbles are categorized into two groups: spherical/distorted bubbles as Group 1 while cap/slug/churn-turbulent bubbles as Group 2. Therefore, this transport equation can be employed in the flow regimes spanning from bubbly, cap bubbly, slug to churn-turbulent flows. However, the introduction of the two groups of bubbles requires two gas velocity fields. Yet it is not practical to solve two momentum equations for the gas phase alone. In the current modified two-fluid model, a simplified approach is proposed. The momentum equation for the averaged velocity of both Group-1 and Group-2 bubbles is retained. By doing so, the velocity difference between Group-1 and Group-2 bubbles needs to be determined. This may be made either based on simplified momentum equations for both Group-1 and Group-2 bubbles or by a modified drift-flux model

Computational analysis of coupled fluid, heat, and mass transport in ferrocyanide single-shell tanks: FY 1994 interim report. Ferrocyanide Tank Safety Project

International Nuclear Information System (INIS)

McGrail, B.P.

1994-11-01

A computer modeling study was conducted to determine whether natural convection processes in single-shell tanks containing ferrocyanide wastes could generate localized precipitation zones that significantly concentrate the major heat-generating radionuclide, 137 Cs. A computer code was developed that simulates coupled fluid, heat, and single-species mass transport on a regular, orthogonal finite-difference grid. The analysis showed that development of a ''hot spot'' is critically dependent on the temperature dependence for the solubility of Cs 2 NiFe(CN) 6 or CsNaNiFe(CN) 6 . For the normal case, where solubility increases with increasing temperature, the net effect of fluid flow, heat, and mass transport is to disperse any local zones of high heat generation rate. As a result, hot spots cannot physically develop for this case. However, assuming a retrograde solubility dependence, the simulations indicate the formation of localized deposition zones that concentrate the 137 Cs near the bottom center of the tank where the temperatures are highest. Recent experimental studies suggest that Cs 2 NiFe(CN) 6 (c) does not exhibit retrograde solubility over the temperature range 25 degree C to 90 degree C and NaOH concentrations to 5 M. Assuming these preliminary results are confirmed, no natural mass transport process exists for generating a hot spot in the ferrocyanide single-shell tanks

Cycling and walking for transport: Estimating net health effects from comparison of different transport mode users' self-reported physical activity.

Science.gov (United States)

Veisten, Knut; Flügel, Stefan; Ramjerdi, Farideh; Minken, Harald

2011-07-20

There is comprehensive evidence of the positive health effects of physical activity, and transport authorities can enable this by developing infrastructure for cycling and walking. In particular, cycling to work or to school can be a relatively high intensity activity that by itself might suffice for maximum health gain. In this paper, we present estimates of net health effects that can be assumed for demand responses to infrastructure development. The estimation was based on comparing current cyclists/pedestrians against potential cyclists/pedestrians, applying the international physical activity questionnaire, which is a survey-based method for estimating metabolic equivalent task levels from self-reported types of physical activity, and their frequency, duration and level of intensity (moderate or vigorous).. By comparing between shares of individuals with medium or high intensity levels, within the segments of current cyclists/pedestrians and potential cyclists/pedestrians, we estimate the possible net health effects of potential new users of improved cycling/walking infrastructure. For an underpinning of the estimates, we also include the respondents' assessments of the extent to which cycling/walking for transport replaces other physical activity, and we carry out a regression of cycling/walking activity levels on individual characteristics and cycle/walk facility features. The estimated share of new regular cyclists obtaining net health gains was ca. 30%, while for new regular pedestrians this was only ca. 15%. These estimates are based on the assumption that the new users of improved cycle/walk facilities are best represented by self-declared potential users of such improved facilities. For potential cyclists/pedestrians, exercise was stated as the main motivation for physical active transport, but among current regular cyclists "fast and flexible" was just as important as exercising. Measured intensity levels from physically active transport increased with

Revisiting low-fidelity two-fluid models for gas–solids transport

Energy Technology Data Exchange (ETDEWEB)

Adeleke, Najeem, E-mail: najm@psu.edu; Adewumi, Michael, E-mail: m2a@psu.edu; Ityokumbul, Thaddeus

2016-08-15

Two-phase gas–solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas–solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe–Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

Revisiting low-fidelity two-fluid models for gas–solids transport

International Nuclear Information System (INIS)

Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

2016-01-01

Two-phase gas–solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas–solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe–Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

Revisiting low-fidelity two-fluid models for gas-solids transport

Science.gov (United States)

Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

2016-08-01

Two-phase gas-solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas-solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe-Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

Fluid/Gravity Correspondence, Second Order Transport and Gravitational Anomaly***

Science.gov (United States)

Megías, Eugenio; Pena-Benitez, Francisco

2014-03-01

We study the transport properties of a relativistic fluid affected by chiral and gauge-gravitational anomalies. The computation is performed in the framework of the fluid/gravity correspondence for a 5 dim holographic model with Chern-Simons terms in the action. We find new anomalous and non anomalous transport coefficients, as well as new contributions to the existing ones coming from the mixed gauge-gravitational anomaly. Consequences for the shear waves dispersion relation are analyzed. Talk given by E. Megías at the International Nuclear Physics Conference INPC 2013, 2-7 June 2013, Firenze, Italy.Supported by Plan Nacional de Altas Energías (FPA2009-07908, FPA2011-25948), Spanish MICINN Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042), Comunidad de Madrid HEP-HACOS S2009/ESP-1473, Spanish MINECO's Centro de Excelencia Severo Ochoa Program (SEV-2012-0234, SEV-2012-0249), and the Juan de la Cierva Program.

Epithelial Fluid Transport is Due to Electro-osmosis (80%), Plus Osmosis (20%).

Science.gov (United States)

Fischbarg, Jorge; Hernandez, Julio A; Rubashkin, Andrey A; Iserovich, Pavel; Cacace, Veronica I; Kusnier, Carlos F

2017-06-01

Epithelial fluid transport, an important physiological process shrouded in a long-standing enigma, may finally be moving closer to a solution. We propose that, for the corneal endothelium, relative proportions for the driving forces for fluid transport are 80% of paracellular electro-osmosis, and 20% classical transcellular osmosis. These operate in a cyclical process with a period of 9.2 s, which is dictated by the decrease and exhaustion of cellular Na + . Paracellular electro-osmosis is sketched here, and partially discussed as much as the subject still allows; transcellular osmosis is presented at length.

Modelling Transcapillary Transport of Fluid and Proteins in Hemodialysis Patients.

Directory of Open Access Journals (Sweden)

Mauro Pietribiasi

Full Text Available The kinetics of protein transport to and from the vascular compartment play a major role in the determination of fluid balance and plasma refilling during hemodialysis (HD sessions. In this study we propose a whole-body mathematical model describing water and protein shifts across the capillary membrane during HD and compare its output to clinical data while evaluating the impact of choosing specific values for selected parameters.The model follows a two-compartment structure (vascular and interstitial space and is based on balance equations of protein mass and water volume in each compartment. The capillary membrane was described according to the three-pore theory. Two transport parameters, the fractional contribution of large pores (αLP and the total hydraulic conductivity (LpS of the capillary membrane, were estimated from patient data. Changes in the intensity and direction of individual fluid and solute flows through each part of the transport system were analyzed in relation to the choice of different values of small pores radius and fractional conductivity, lymphatic sensitivity to hydraulic pressure, and steady-state interstitial-to-plasma protein concentration ratio.The estimated values of LpS and αLP were respectively 10.0 ± 8.4 mL/min/mmHg (mean ± standard deviation and 0.062 ± 0.041. The model was able to predict with good accuracy the profiles of plasma volume and serum total protein concentration in most of the patients (average root-mean-square deviation < 2% of the measured value.The applied model provides a mechanistic interpretation of fluid transport processes induced by ultrafiltration during HD, using a minimum of tuned parameters and assumptions. The simulated values of individual flows through each kind of pore and lymphatic absorption rate yielded by the model may suggest answers to unsolved questions on the relative impact of these not-measurable quantities on total vascular refilling and fluid balance.

Transport of fluid and solutes in the body I. Formulation of a mathematical model.

Science.gov (United States)

Gyenge, C C; Bowen, B D; Reed, R K; Bert, J L

1999-09-01

A compartmental model of short-term whole body fluid, protein, and ion distribution and transport is formulated. The model comprises four compartments: a vascular and an interstitial compartment, each with an embedded cellular compartment. The present paper discusses the assumptions on which the model is based and describes the equations that make up the model. Fluid and protein transport parameters from a previously validated model as well as ionic exchange parameters from the literature or from statistical estimation [see companion paper: C. C. Gyenge, B. D. Bowen, R. K. Reed, and J. L. Bert. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1228-H1240, 1999] are used in formulating the model. The dynamic model has the ability to simulate 1) transport across the capillary membrane of fluid, proteins, and small ions and their distribution between the vascular and interstitial compartments; 2) the changes in extracellular osmolarity; 3) the distribution and transport of water and ions associated with each of the cellular compartments; 4) the cellular transmembrane potential; and 5) the changes of volume in the four fluid compartments. The validation and testing of the proposed model against available experimental data are presented in the companion paper.

Net Analyte Signal Standard Additions Method for Simultaneous Determination of Sulfamethoxazole and Trimethoprim in Pharmaceutical Formulations and Biological Fluids

Directory of Open Access Journals (Sweden)

M. H. Givianrad

2012-01-01

Full Text Available The applicability of a novel net analyte signal standard addition method (NASSAM to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim was verified by UV-visible spectrophotometry. The results confirmed that the net analyte signal standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. Moreover, applying the net analyte signal standard additions method revealed that the two drugs could be determined simultaneously with the concentration ratios of sulfamethoxazole to trimethoprim varying from 1:35 to 60:1 in the mixed samples. In addition, the limits of detections were 0.26 and 0.23 μmol L-1 for sulfamethoxazole and trimethoprim, respectively. The proposed method has been effectively applied to the simultaneous determination of sulfamethoxazole and trimethoprim in some synthetic, pharmaceutical formulation and biological fluid samples.

Fluid absorption related to ion transport in human airway epithelial spheroids

DEFF Research Database (Denmark)

Pedersen, P S; Holstein-Rathlou, N H; Larsen, P L

1999-01-01

, and amiloride inhibited both values. Fluid transport rates were calculated from repeated measurements of spheroid diameters. The results showed that 1) non-CF and CF spheroids absorbed fluid at identical rates (4.4 microl x cm(-2) x h(-1)), 2) amiloride inhibited fluid absorption to a lower residual level...... in non-CF than in CF spheroids, 3) Cl(-)-channel inhibitors increased fluid absorption in amiloride-treated non-CF spheroids to a level equal to that of amiloride-treated CF spheroids, 4) hydrochlorothiazide reduced the amiloride-insensitive fluid absorption in both non-CF and CF spheroids, and 5......) osmotic water permeabilities were equal in non-CF and CF spheroids ( approximately 27 x 10(-7) cm x s(-1) x atm(-1))....

Transport of gases between the environment and alveoli – theoretical foundations

OpenAIRE

Butler, James P.; Tsuda, Akira

2011-01-01

The transport of oxygen and carbon dioxide in the gas phase from the ambient environment to and from the alveolar gas/blood interface is accomplished through the tracheobronchial tree, and involves mechanisms of bulk or convective transport and diffusive net transport. The geometry of the airway tree and the fluid dynamics of these two transport processes combine in such a way that promotes a classical fractionation of ventilation into dead space and alveolar ventilation respectively. This si...

Fluid Physical and Transport Phenomena Studies aboard the International Space Station: Planned Experiments

Science.gov (United States)

Singh, Bhim S.

1999-01-01

This paper provides an overview of the microgravity fluid physics and transport phenomena experiments planned for the International Spare Station. NASA's Office of Life and Microgravity Science and Applications has established a world-class research program in fluid physics and transport phenomena. This program combines the vast expertise of the world research community with NASA's unique microgravity facilities with the objectives of gaining new insight into fluid phenomena by removing the confounding effect of gravity. Due to its criticality to many terrestrial and space-based processes and phenomena, fluid physics and transport phenomena play a central role in the NASA's Microgravity Program. Through widely publicized research announcement and well established peer-reviews, the program has been able to attract a number of world-class researchers and acquired a critical mass of investigations that is now adding rapidly to this field. Currently there arc a total of 106 ground-based and 20 candidate flight principal investigators conducting research in four major thrust areas in the program: complex flows, multiphase flow and phase change, interfacial phenomena, and dynamics and instabilities. The International Space Station (ISS) to be launched in 1998, provides the microgravity research community with a unprecedented opportunity to conduct long-duration microgravity experiments which can be controlled and operated from the Principal Investigators' own laboratory. Frequent planned shuttle flights to the Station will provide opportunities to conduct many more experiments than were previously possible. NASA Lewis Research Center is in the process of designing a Fluids and Combustion Facility (FCF) to be located in the Laboratory Module of the ISS that will not only accommodate multiple users but, allow a broad range of fluid physics and transport phenomena experiments to be conducted in a cost effective manner.

Control of optical transport parameters of 'porous medium – supercritical fluid' systems

Energy Technology Data Exchange (ETDEWEB)

Zimnyakov, D A; Ushakova, O V; Yuvchenko, S A [Yuri Gagarin State Technical University of Saratov, Saratov (Russian Federation); Bagratashvili, V N [M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2015-11-30

The possibility of controlling optical transport parameters (in particular, transport scattering coefficient) of porous systems based on polymer fibres, saturated with carbon dioxide in different phase states (gaseous, liquid and supercritical) has been experimentally studied. An increase in the pressure of the saturating medium leads to a rise of its refractive index and, correspondingly, the diffuse-transmission coefficient of the system due to the decrease in the transport scattering coefficient. It is shown that, in the case of subcritical saturating carbon dioxide, the small-angle diffuse transmission of probed porous layers at pressures close to the saturated vapour pressure is determined by the effect of capillary condensation in pores. The immersion effect in 'porous medium – supercritical fluid' systems, where the fluid pressure is used as a control parameter, is considered. The results of reconstructing the values of transport scattering coefficient of probed layers for different refractive indices of a saturating fluid are presented. (radiation scattering)

Transport properties of the fluid produced at Relativistic Heavy-Ion ...

Indian Academy of Sciences (India)

relativistic fluid dynamics, the kinematic viscosity (ν) is defined as ν = ... because the momentum transport mechanisms are different in the two cases (see, ..... of the widths of giant resonances within the hydrodynamic model (ii) the process.

Cerebrospinal and interstitial fluid transport via the glymphatic pathway modeled by optimal mass transport.

Science.gov (United States)

Ratner, Vadim; Gao, Yi; Lee, Hedok; Elkin, Rena; Nedergaard, Maiken; Benveniste, Helene; Tannenbaum, Allen

2017-05-15

The glymphatic pathway is a system which facilitates continuous cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange and plays a key role in removing waste products from the rodent brain. Dysfunction of the glymphatic pathway may be implicated in the pathophysiology of Alzheimer's disease. Intriguingly, the glymphatic system is most active during deep wave sleep general anesthesia. By using paramagnetic tracers administered into CSF of rodents, we previously showed the utility of MRI in characterizing a macroscopic whole brain view of glymphatic transport but we have yet to define and visualize the specific flow patterns. Here we have applied an alternative mathematical analysis approach to a dynamic time series of MRI images acquired every 4min over ∼3h in anesthetized rats, following administration of a small molecular weight paramagnetic tracer into the CSF reservoir of the cisterna magna. We use Optimal Mass Transport (OMT) to model the glymphatic flow vector field, and then analyze the flow to find the network of CSF-ISF flow channels. We use 3D visualization computational tools to visualize the OMT defined network of CSF-ISF flow channels in relation to anatomical and vascular key landmarks from the live rodent brain. The resulting OMT model of the glymphatic transport network agrees largely with the current understanding of the glymphatic transport patterns defined by dynamic contrast-enhanced MRI revealing key CSF transport pathways along the ventral surface of the brain with a trajectory towards the pineal gland, cerebellum, hypothalamus and olfactory bulb. In addition, the OMT analysis also revealed some interesting previously unnoticed behaviors regarding CSF transport involving parenchymal streamlines moving from ventral reservoirs towards the surface of the brain, olfactory bulb and large central veins. Copyright © 2017. Published by Elsevier Inc.

Fluid and gyrokinetic simulations of impurity transport at JET

DEFF Research Database (Denmark)

Nordman, H; Skyman, A; Strand, P

2011-01-01

Impurity transport coefficients due to ion-temperature-gradient (ITG) mode and trapped-electron mode turbulence are calculated using profile data from dedicated impurity injection experiments at JET. Results obtained with a multi-fluid model are compared with quasi-linear and nonlinear gyrokinetic...... simulation results obtained with the code GENE. The sign of the impurity convective velocity (pinch) and its various contributions are discussed. The dependence of the impurity transport coefficients and impurity peaking factor −∇nZ/nZ on plasma parameters such as impurity charge number Z, ion logarithmic...

Learning from jellyfish: Fluid transport in muscular pumps at intermediate Reynolds numbers

Science.gov (United States)

Nawroth, Janna; Dabiri, John

2010-11-01

Biologically inspired hydrodynamic propulsion and maneuvering strategies promise the advancement of medical implants and minimally invasive clinical tools. We have chosen juvenile jellyfish as a model system for investigating fluid dynamics and morphological properties underlying fluid transport by a muscular pump at intermediate Reynolds numbers. Recently we have described how natural variations in viscous forces are balanced by changes in jellyfish body shape (phenotypic plasticity), to the effect of facilitating efficient body-fluid interaction. Complementing these studies in our live model organisms, we are also engaged in engineering an artificial jellyfish, that is, a jellyfish-inspired construct of a flexible plastic sheet actuated by a monolayer of rat cardiomyocytes. The main challenges here are (1) to derive a body shape and deformation suitable for effective fluid transport under physiological conditions, (2) to understand the mechanical properties of the muscular film and derive a design capable of the desired deformation, (3) to master the proper alignment and timely contraction of the muscle component needed to achieve the desired deformation, and (4) to evaluate the performance of the design.

Fluid Petri Nets and hybrid model-checking: a comparative case study

International Nuclear Information System (INIS)

Gribaudo, M.; Horvath, A.; Bobbio, A.; Tronci, E.; Ciancamerla, E.; Minichino, M.

2003-01-01

The modeling and analysis of hybrid systems is a recent and challenging research area which is actually dominated by two main lines: a functional analysis based on the description of the system in terms of discrete state (hybrid) automata (whose goal is to ascertain conformity and reachability properties), and a stochastic analysis (whose aim is to provide performance and dependability measures). This paper investigates a unifying view between formal methods and stochastic methods by proposing an analysis methodology of hybrid systems based on Fluid Petri Nets (FPNs). FPNs can be analyzed directly using appropriate tools. Our paper shows that the same FPN model can be fed to different functional analyzers for model checking. In order to extensively explore the capability of the technique, we have converted the original FPN into languages for discrete as well as hybrid as well as stochastic model checkers. In this way, a first comparison among the modeling power of well known tools can be carried out. Our approach is illustrated by means of a 'real world' hybrid system: the temperature control system of a co-generative plant

Theory and computer simulation of structure, transport, and flow of fluid in micropores

International Nuclear Information System (INIS)

Davis, H.T.; Bitsanis, I.; Vanderlick, T.K.; Tirrell, M.V.

1987-01-01

An overview is given of recent progress made in our laboratory on this topic. The density profiles of fluid in micropores are found by solving numerically an approximate Yvon-Born-Green equation. A related local average density model (LADM) allows prediction of transport and flow in inhomogeneous fluids from density profiles. A rigorous extension of the Enskog theory of transport is also outlined. Simple results of this general approach for the tracer diffusion and Couette flow between planar micropore walls are presented. Equilibrium and flow (molecular dynamics) simulations are compared with the theoretical predictions. Simulated density profiles of the micropore fluid exhibit substantial fluid layering. The number and sharpness of fluid layers depend sensitively on the pore width. The solvation force and the pore average density and diffusivity are oscillating functions of the pore width. The theoretical predictions for these quantities agree qualitatively with the simulation results. The flow simulations indicate that the flow does not affect the fluid structure and diffusivity even at extremely high shear rates (10/sup 10/s/sup -1/). The fluid structure induces large deviations of the shear stress and the effective viscosity from the bulk fluid values. The flow velocity profiles are correlated with the density profiles and differ from those of a bulk fluid. The LADM and extended Enskog theory predictions for the velocity profiles and the pore average diffusivity agree very well with each other and with the simulation results. The LADM predictions for the shear stress and the effective viscosity agrees fairly well with the simulation results

Modeling fluid transport in 2d paper networks

Science.gov (United States)

Tirapu Azpiroz, Jaione; Fereira Silva, Ademir; Esteves Ferreira, Matheus; Lopez Candela, William Fernando; Bryant, Peter William; Ohta, Ricardo Luis; Engel, Michael; Steiner, Mathias Bernhard

2018-02-01

Paper-based microfluidic devices offer great potential as a low-cost platform to perform chemical and biochemical tests. Commercially available formats such as dipsticks and lateral-flow test devices are widely popular as they are easy to handle and produce fast and unambiguous results. While these simple devices lack precise control over the flow to enable integration of complex functionality for multi-step processes or the ability to multiplex several tests, intense research in this area is rapidly expanding the possibilities. Modeling and simulation is increasingly more instrumental in gaining insight into the underlying physics driving the processes inside the channels, however simulation of flow in paper-based microfluidic devices has barely been explored to aid in the optimum design and prototyping of these devices for precise control of the flow. In this paper, we implement a multiphase fluid flow model through porous media for the simulation of paper imbibition of an incompressible, Newtonian fluid such as when water, urine or serum is employed. The formulation incorporates mass and momentum conservation equations under Stokes flow conditions and results in two coupled Darcy's law equations for the pressures and saturations of the wetting and non-wetting phases, further simplified to the Richard's equation for the saturation of the wetting fluid, which is then solved using a Finite Element solver. The model tracks the wetting fluid front as it displaces the non-wetting fluid by computing the time-dependent saturation of the wetting fluid. We apply this to the study of liquid transport in two-dimensional paper networks and validate against experimental data concerning the wetting dynamics of paper layouts of varying geometries.

Fluid and gyrokinetic modelling of particle transport in plasmas with hollow density profiles

International Nuclear Information System (INIS)

Tegnered, D; Oberparleiter, M; Nordman, H; Strand, P

2016-01-01

Hollow density profiles occur in connection with pellet fuelling and L to H transitions. A positive density gradient could potentially stabilize the turbulence or change the relation between convective and diffusive fluxes, thereby reducing the turbulent transport of particles towards the center, making the fuelling scheme inefficient. In the present work, the particle transport driven by ITG/TE mode turbulence in regions of hollow density profiles is studied by fluid as well as gyrokinetic simulations. The fluid model used, an extended version of the Weiland transport model, Extended Drift Wave Model (EDWM), incorporates an arbitrary number of ion species in a multi-fluid description, and an extended wavelength spectrum. The fluid model, which is fast and hence suitable for use in predictive simulations, is compared to gyrokinetic simulations using the code GENE. Typical tokamak parameters are used based on the Cyclone Base Case. Parameter scans in key plasma parameters like plasma β, R/L T , and magnetic shear are investigated. It is found that β in particular has a stabilizing effect in the negative R/L n region, both nonlinear GENE and EDWM show a decrease in inward flux for negative R/L n and a change of direction from inward to outward for positive R/L n . This might have serious consequences for pellet fuelling of high β plasmas. (paper)

Geometry of tidal inlet systems : A key factor for the net sediment transport in tidal inlets

NARCIS (Netherlands)

Ridderinkhof, W.; de Swart, H. E.; van der Vegt, M.; Alebregtse, N. C.; Hoekstra, P.

2014-01-01

The net transport of sediment between the back-barrier basin and the sea is an important process for determining the stability of tidal inlet systems. Earlier studies showed that in a short basin, tidal flats favor peak ebb-currents stronger than peak flood currents, implying export of coarse

Computer Modeling of Sand Transport on Mars Using a Compart-Mentalized Fluids Algorithm (CFA)

Science.gov (United States)

Marshall, J.; Stratton, D.

1999-01-01

of sand comminution on Mars. A multiple-grain transport model using just the equations of grain motion describing lift and drag is impossible to develop owing to stochastic effects --the very effects we wish to model. Also, unless we were to employ supercomputing techniques and extremely complex computer codes that could deal with millions of grains simultaneously, it would also be difficult to model grain transport if we attempted to consider every grain in motion. No existing computer models were found that satisfactorily used the equations of motion to arrive at transport flux numbers for the different populations of saltation and reptation. Modeling all the grains in a transport system was an intractable problem within our resources, and thus we developed what we believe to be a new modeling approach to simulating grain transport. The CFA deals with grain populations, but considers them to belong to various compartmentalized fluid units in the boundary layer. In this way, the model circumvents the multigrain problem by dealing primarily with the consequences of grain transport --momentum transfer between air and grains, which is the physical essence of a dynamic grain-fluid mixture. We thus chose to model the aeolian transport process as a superposition of fluids. These fluids include the air as well as particle populations of various properties. The prime property distinguishing these fluids is upward and downward grain motion. In a normal saltation trajectory, a grain's downwind velocity increases with time, so a rising grain will have a smaller downwind velocity than a failing grain. Because of this disparity in rising and falling grain proper-ties, it seemed appropriate to track these as two separate grain populations within the same physical space. The air itself can be considered a separate fluid superimposed within and interacting with the various grain-cloud "fluids". Additional informaiton is contained in the original.

Peristaltic transport of Johnson-Segalman fluid under effect of a magnetic field

Directory of Open Access Journals (Sweden)

Moustafa Elshahed

2005-01-01

Full Text Available The peristaltic transport of Johnson-Segalman fluid by means of an infinite train of sinusoidal waves traveling along the walls of a two-dimensional flexible channel is investigated. The fluid is electrically conducted by a transverse magnetic field. A perturbation solution is obtained for the case in which amplitude ratio is small. Numerical results are reported for various values of the physical parameters of interest.

A coupled reaction and transport model for assessing the injection, migration and fate of waste fluids

International Nuclear Information System (INIS)

Liu, X.; Ortoleva, P.

1996-01-01

The use of reaction-transport modeling for reservoir assessment and management in the context of deep well waste injection is evaluated. The study is based on CIRF.A (Chemical Interaction of Rock and Fluid), a fully coupled multiphase flow, contaminant transport, and fluid and mineral reaction model. Although SWIFT (Sandia Waste-Isolation Flow and Transport Model) is often the numerical model of choice, it can not account for chemical reactions involving rock, wastes, and formation fluids and their effects on contaminant transport, rock permeability and porosity, and the integrity of the reservoir and confining units. CIRF.A can simulate all these processes. Two field cases of waste injection were simulated by CIRF.A. Both observation data and simulation results show mineral precipitation in one case and rock dissolution in another case. Precipitation and dissolution change rock porosity and permeability, and hence the pattern of fluid migration. The model is shown to be invaluable in analyzing near borehole and reservoir-scale effects during waste injection and predicting the 10,000 year fate of the waste plume. The benefits of using underpressured compartments as waste repositories were also demonstrated by CIRF.A simulations

Fast Propagation in Fluid Transport Models with Evolution of Turbulence Saturation

International Nuclear Information System (INIS)

Lopez-Bruna, D.

2012-01-01

This report compiles and extends two works on models that reproduce the experimental facts of non local transport and pulse propagation in magnetically confined fusion plasmas. The works are based on fluid transport models, originally designed to explain the formation of edge or internal transport barriers, that include fast evolution equations for the particle and heat fluxes. The heating of the plasma core in response to a sudden edge cooling or the propagation of turbulent fronts around transport barriers are a consequence of the competing roles of linear drive and non-linear reduction of the turbulent fluxes. Possibilities to use the models to interpret TJ-II plasmas are discussed. (Author) 62 refs.

Fast Propagation in Fluid Transport Models with Evolution of Turbulence Saturation

Energy Technology Data Exchange (ETDEWEB)

Lopez-Bruna, D.

2012-07-01

This report compiles and extends two works on models that reproduce the experimental facts of non local transport and pulse propagation in magnetically confined fusion plasmas. The works are based on fluid transport models, originally designed to explain the formation of edge or internal transport barriers, that include fast evolution equations for the particle and heat fluxes. The heating of the plasma core in response to a sudden edge cooling or the propagation of turbulent fronts around transport barriers are a consequence of the competing roles of linear drive and non-linear reduction of the turbulent fluxes. Possibilities to use the models to interpret TJ-II plasmas are discussed. (Author) 62 refs.

cAMP Stimulates Transepithelial Short-Circuit Current and Fluid Transport Across Porcine Ciliary Epithelium.

Science.gov (United States)

Cheng, Angela King-Wah; Civan, Mortimer M; To, Chi-Ho; Do, Chi-Wai

2016-12-01

To investigate the effects of cAMP on transepithelial electrical parameters and fluid transport across porcine ciliary epithelium. Transepithelial electrical parameters were determined by mounting freshly isolated porcine ciliary epithelium in a modified Ussing chamber. Similarly, fluid movement across intact ciliary body was measured with a custom-made fluid flow chamber. Addition of 1, 10, and 100 μM 8-Br-cAMP (cAMP) to the aqueous side (nonpigmented ciliary epithelium, NPE) induced a sustained increase in short-circuit current (Isc). Addition of niflumic acid (NFA) to the aqueous surface effectively blocked the cAMP-induced Isc stimulation. The administration of cAMP to the stromal side (pigmented ciliary epithelium, PE) triggered a significant stimulation of Isc only at 100 μM. No additive effect was observed with bilateral application of cAMP. Likewise, forskolin caused a significant stimulation of Isc when applied to the aqueous side. Concomitantly, cAMP and forskolin increased fluid transport across porcine ciliary epithelium, and this stimulation was effectively inhibited by aqueous NFA. Depleting Cl- in the bathing solution abolished the baseline Isc and inhibited the subsequent stimulation by cAMP. Pretreatment with protein kinase A (PKA) blockers (H89/KT5720) significantly inhibited the cAMP- and forskolin-induced Isc responses. Our results suggest that cAMP triggers a sustained stimulation of Cl- and fluid transport across porcine ciliary epithelium; Cl- channels in the NPE cells are potentially a cellular site for this PKA-sensitive cAMP-mediated response.

Computational transport phenomena of fluid-particle systems

CERN Document Server

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...

Influence of deformation on the fluid transport properties of salt rocks

NARCIS (Netherlands)

Peach, C.J.

1991-01-01

While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They

Osmoregulation and epithelial water transport: lessons from the intestine of marine teleost fish.

Science.gov (United States)

Whittamore, Jonathan M

2012-01-01

For teleost fish living in seawater, drinking the surrounding medium is necessary to avoid dehydration. This is a key component of their osmoregulatory strategy presenting the challenge of excreting excess salts while achieving a net retention of water. The intestine has an established role in osmoregulation, and its ability to effectively absorb fluid is crucial to compensating for water losses to the hyperosmotic environment. Despite this, the potential for the teleost intestine to serve as a comparative model for detailed, integrative experimental studies on epithelial water transport has so far gone largely untapped. The following review aims to present an assessment of the teleost intestine as a fluid-transporting epithelium. Beginning with a brief overview of marine teleost osmoregulation, emphasis shifts to the processing of ingested seawater by the gastrointestinal tract and the characteristics of intestinal ion and fluid transport. Particular attention is given to acid-base transfers by the intestine, specifically bicarbonate secretion, which creates the distinctly alkaline gut fluids responsible for the formation of solid calcium carbonate precipitates. The respective contributions of these unique features to intestinal fluid absorption, alongside other recognised ion transport processes, are then subsequently considered within the wider context of the classic physiological problem of epithelial water transport.

Petri Net Approach of Collision Prevention Supervisor Design in Port Transport System

Directory of Open Access Journals (Sweden)

Danko Kezić

2007-09-01

Full Text Available Modern port terminals are equipped with various localtransport systems, which have the main task to transport cargobetween local storehouses and transport resources (ships,trains, trucks in the fastest and most efficient way, and at thelowest possible cost. These local transport systems consist offully automated transport units (AGV- automatic guided vehiclewhich are controlled by the computer system. The portcomputer system controls the fully automated transport units inthe way to avoid possible deadlocks and collisions betweenthem. However, beside the fully automated local transportunits, there are human operated transport units (fork-lifttrucks, cranes etc. which cross the path oftheAGVfrom timeto time. The collision of human operated transp011 unit andA GV is possible due to human inattention. To solve this problem,it is necesswy to design a supe1vismy control system thatcoordinates and controls both human driven transport unit andA G V In other words, the human-machine interactions need tobe supen·ised. The supen•ising system can be realized in the waythat the port terminal is divided into zones. Vehicle movementsare supen•ised by a video system which detects the moving ofparticular l'ehicles as a discrete event. Based on detected events,dangerous moving of certain vehicles is blocked by the supe1visi11gsystem. The paper considers the design of collision preventionsupen•isor by using discrete event dynamic themy. The portterminal is modeled by using ordi1za1y Petri nets. The design ofcollision prevention supe1visor is cmTied out by using the P-inl'ariantmethod. The verification of the supervisor is done bycomputer simulation.

Influence of deformation on the fluid transport properties of salt rocks

NARCIS (Netherlands)

Peach, C.J.

1991-01-01

While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They are

Space Geodesy Monitoring Mass Transport in Global Geophysical Fluids

Science.gov (United States)

Chao, Benjamin F.

2004-01-01

Mass transports occurring in the atmosphere-hydrosphere-cryosphere-solid Earth-core system (the 'global geophysical fluids') are important geophysical phenomena. They occur on all temporal and spatial scales. Examples include air mass and ocean circulations, oceanic and solid tides, hydrological water and idsnow redistribution, mantle processes such as post-glacial rebound, earthquakes and tectonic motions, and core geodynamo activities. The temporal history and spatial pattern of such mass transport are often not amenable to direct observations. Space geodesy techniques, however, have proven to be an effective tool in monitorihg certain direct consequences of the mass transport, including Earth's rotation variations, gravitational field variations, and the geocenter motion. Considerable advances have been made in recent years in observing and understanding of these geodynamic effects. This paper will use several prominent examples to illustrate the triumphs in research over the past years under a 'Moore's law' in space geodesy. New space missions and projects promise to further advance our knowledge about the global mass transports. The latter contributes to our understanding of the geophysical processes that produce and regulate the mass transports, as well as of the solid Earth's response to such changes in terms of Earth's mechanical properties.

Fluid/gravity correspondence: second order transport coefficients in compactified D4-branes

International Nuclear Information System (INIS)

Wu, Chao; Chen, Yidian; Huang, Mei

2017-01-01

We develop the boundary derivative expansion (BDE) formalism of fluid/gravity correspondence to nonconformal version through the compactified, near-extremal black D4-brane. We offer an explicit calculation of 9 second order transport coefficients, i.e., the τ π , τ π ∗ , τ Π , λ 1,2,3 and ξ 1,2,3 for the strongly coupled, uncharged and nonconformal relativistic fluid which is the holographic dual of compactified, near extremal black D4-brane. We also show that the nonconformal fluid considered in this work is free of causal problem and admits the Haack-Yarom relation 4λ 1 −λ 2 =2ητ π .

Lagrangian transport characteristics of a class of three-dimensional inline-mixing flows with fluid inertia

NARCIS (Netherlands)

Speetjens, M.F.M.; Demissie, E.A.; Metcalfe, G.; Clercx, H.J.H.

2014-01-01

Laminar mixing by the inline-mixing principle is key to many industrial fluids-engineering systems of size extending from microns to meters. However, insight into fundamental transport phenomena particularly under the realistic conditions of three-dimensionality (3D) and fluid inertia remains

A modified two-fluid model for the application of two-group interfacial area transport equation

International Nuclear Information System (INIS)

Sun, X.; Ishii, M.; Kelly, J.

2003-01-01

This paper presents the modified two-fluid model that is ready to be applied in the approach of the two-group interfacial area transport equation. The two-group interfacial area transport equation was developed to provide a mechanistic constitutive relation for the interfacial area concentration in the two-fluid model. In the two-group transport equation, bubbles are categorized into two groups: spherical/distorted bubbles as Group 1 while cap/slug/churn-turbulent bubbles as Group 2. Therefore, this transport equation can be employed in the flow regimes spanning from bubbly, cap bubbly, slug to churn-turbulent flows. However, the introduction of the two groups of bubbles requires two gas velocity fields. Yet it is not desirable to solve two momentum equations for the gas phase alone. In the current modified two-fluid model, a simplified approach is proposed. The momentum equation for the averaged velocity of both Group-1 and Group-2 bubbles is retained. By doing so, the velocity difference between Group-1 and Group-2 bubbles needs to be determined. This may be made either based on simplified momentum equations for both Group-1 and Group-2 bubbles or by a modified drift-flux model

Biocompatibility of peritoneal dialysis fluids: long-term exposure of nonuremic rats.

Science.gov (United States)

Musi, Barbara; Braide, Magnus; Carlsson, Ola; Wieslander, Anders; Albrektsson, Ann; Ketteler, Markus; Westenfeld, Ralf; Floege, Jürgen; Rippe, Bengt

2004-01-01

Long-term peritoneal dialysis (PD) leads to structural and functional changes in the peritoneum. The aim of the present study was to investigate the long-term effects of PD fluid components, glucose and glucose degradation products (GDP), and lactate-buffered solution on morphology and transport characteristics in a nonuremic rat model. Rats were subjected to two daily intraperitoneal injections (20 mL/day) during 12 weeks of one of the following: commercial PD fluid (Gambrosol, 4%; Gambro AB, Lund, Sweden), commercial PD fluid with low GDP levels (Gambrosol trio, 4%; Gambro AB), sterile-filtered PD fluid (4%) without GDP, or a glucose-free lactate-buffered PD fluid. Punctured and untreated controls were used. Following exposure, the rats underwent a single 4-hour PD dwell (30 mL, 4% glucose) to determine peritoneal function. Additionally, submesothelial tissue thickness, percentage of high mesothelial cells (perpendicular diameter > 2 microm), vascular density, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF) beta1 mRNA expression were determined. Submesothelial collagen concentration was estimated by van Gieson staining. Submesothelial tissue thickness and vascular density, mediated by VEGF and TGFbeta production, in the diaphragmatic peritoneum increased significantly in rats exposed to any PD fluid. Gambrosol induced a marked increased fibrosis of the hepatic peritoneum. A significant increase in high mesothelial cells was observed in the Gambrosol group only. Net ultrafiltration was reduced in the Gambrosol and in the glucose-free groups compared to untreated controls. Small solute transport was unchanged, but all groups exposed to fluids showed significantly increased lymph flow. Our results show that long-term exposure to different components of PD fluids leads to mesothelial cell damage, submesothelial fibrosis, and neoangiogenesis. Mesothelial cell damage could be connected to the presence of GDP; the other changes were

Effects of Channel Geometry and Coolant Fluid on Thermoelectric Net Power

DEFF Research Database (Denmark)

Rezaniakolaei, Alireza; Rosendahl, Lasse; Sørensen, Kim

2014-01-01

Channel geometry has a strong influence on the heat transfer coefficient and cooling energy input in a heat sink. The net power output in a thermoelectric generator (TEG) can be defined as power generation minus the required cooling energy in TEG. This study aims to evaluate the net power generat......, and the maximum net power output occurs at smaller Reynolds number when the channel hydraulic diameter reduces....... generation in TEG for different size of hydraulic diameter of plate-fin heat sink and over a wide range of Reynolds number. The particular focus of this study is to find optimal Reynolds number in each considered channel hydraulic diameter and to explore optimal channel hydraulic diameter for maximum TEG net...

Formulation of the Chip Cleanability Mechanics from Fluid Transport

OpenAIRE

Garg, Saurabh; Dornfeld, David; Klaus Berger

2009-01-01

The presence of solid particle contaminant chips in high performance and complex automotive components like cylinder heads of internal combustion engines is a source of major concern for the automotive industry. Current industrial cleaning technologies, simply relying on the fluid transport energy of high pressure or intermittent high impulse jets discharged at the water jacket inlets of the cylinder head, fail to capture the dynamics of interaction between the chip morphology and the complex...

Coupled particle–fluid transport and magnetic separation in microfluidic systems with passive magnetic functionality

International Nuclear Information System (INIS)

Khashan, Saud A; Furlani, Edward P

2013-01-01

A study is presented of coupled particle–fluid transport and field-directed particle capture in microfluidic systems with passive magnetic functionality. These systems consist of a microfluidic flow cell on a substrate that contains embedded magnetic elements. Two systems are considered that utilize soft- and hard-magnetic elements, respectively. In the former, an external field is applied to magnetize the elements, and in the latter, they are permanently magnetized. The field produced by the magnetized elements permeates into the flow cell giving rise to an attractive force on magnetic particles that flow through it. The systems are studied using a novel numerical/closed-form modelling approach that combines numerical transport analysis with closed-form field analysis. Particle–fluid transport is computed using computational fluid dynamics (CFD), while the magnetic force that governs particle capture is obtained in closed form. The CFD analysis takes into account dominant particle forces and two-way momentum transfer between the particles and the fluid. The two-way particle–fluid coupling capability is an important feature of the model that distinguishes it from more commonly used and simplified one-way coupling analysis. The model is used to quantify the impact of two-way particle–fluid coupling on both the capture efficiency and the flow pattern in the systems considered. Many effects such as particle-induced flow-enhanced capture efficiency and flow circulation are studied that cannot be predicted using one-way coupling analysis. In addition, dilute particle dispersions are shown to exhibit significant localized particle–fluid coupling near the capture regions, which contradicts the commonly held view that two-way coupling can be ignored when analysing high-gradient magnetic separation involving such particle systems. Overall, the model demonstrates that two-way coupling needs to be taken into account for rigorous predictions of capture efficiency

Mechanistic Fluid Transport Model to Estimate Gastrointestinal Fluid Volume and Its Dynamic Change Over Time.

Science.gov (United States)

Yu, Alex; Jackson, Trachette; Tsume, Yasuhiro; Koenigsknecht, Mark; Wysocki, Jeffrey; Marciani, Luca; Amidon, Gordon L; Frances, Ann; Baker, Jason R; Hasler, William; Wen, Bo; Pai, Amit; Sun, Duxin

2017-11-01

Gastrointestinal (GI) fluid volume and its dynamic change are integral to study drug disintegration, dissolution, transit, and absorption. However, key questions regarding the local volume and its absorption, secretion, and transit remain unanswered. The dynamic fluid compartment absorption and transit (DFCAT) model is proposed to estimate in vivo GI volume and GI fluid transport based on magnetic resonance imaging (MRI) quantified fluid volume. The model was validated using GI local concentration of phenol red in human GI tract, which was directly measured by human GI intubation study after oral dosing of non-absorbable phenol red. The measured local GI concentration of phenol red ranged from 0.05 to 168 μg/mL (stomach), to 563 μg/mL (duodenum), to 202 μg/mL (proximal jejunum), and to 478 μg/mL (distal jejunum). The DFCAT model characterized observed MRI fluid volume and its dynamic changes from 275 to 46.5 mL in stomach (from 0 to 30 min) with mucus layer volume of 40 mL. The volumes of the 30 small intestine compartments were characterized by a max of 14.98 mL to a min of 0.26 mL (0-120 min) and a mucus layer volume of 5 mL per compartment. Regional fluid volumes over 0 to 120 min ranged from 5.6 to 20.38 mL in the proximal small intestine, 36.4 to 44.08 mL in distal small intestine, and from 42 to 64.46 mL in total small intestine. The DFCAT model can be applied to predict drug dissolution and absorption in the human GI tract with future improvements.

Second-order transport, quasinormal modes and zero-viscosity limit in the Gauss-Bonnet holographic fluid

Energy Technology Data Exchange (ETDEWEB)

Grozdanov, Sašo [Instituut-Lorentz for Theoretical Physics, Leiden University, Niels Bohrweg 2, Leiden 2333 CA (Netherlands); Starinets, Andrei O. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2017-03-30

Gauss-Bonnet holographic fluid is a useful theoretical laboratory to study the effects of curvature-squared terms in the dual gravity action on transport coefficients, quasinormal spectra and the analytic structure of thermal correlators at strong coupling. To understand the behavior and possible pathologies of the Gauss-Bonnet fluid in 3+1 dimensions, we compute (analytically and non-perturbatively in the Gauss-Bonnet coupling) its second-order transport coefficients, the retarded two- and three-point correlation functions of the energy-momentum tensor in the hydrodynamic regime as well as the relevant quasinormal spectrum. The Haack-Yarom universal relation among the second-order transport coefficients is violated at second order in the Gauss-Bonnet coupling. In the zero-viscosity limit, the holographic fluid still produces entropy, while the momentum diffusion and the sound attenuation are suppressed at all orders in the hydrodynamic expansion. By adding higher-derivative electromagnetic field terms to the action, we also compute corrections to charge diffusion and identify the non-perturbative parameter regime in which the charge diffusion constant vanishes.

Coupled processes of fluid flow, solute transport, and geochemical reactions in reactive barriers

Energy Technology Data Exchange (ETDEWEB)

Kim, Jeongkon; Schwartz, Franklin W.; Xu, Tianfu; Choi, Heechul, and Kim, In S.

2004-01-02

A complex pattern of coupling between fluid flow and mass transport develops when heterogeneous reactions occur. For instance, dissolution and precipitation reactions can change a porous medium's physical properties, such as pore geometry and thus permeability. These changes influence fluid flow, which in turn impacts the composition of dissolved constituents and the solid phases, and the rate and direction of advective transport. Two-dimensional modeling studies using TOUGHREACT were conducted to investigate the coupling between flow and transport developed as a consequence of differences in density, dissolution precipitation, and medium heterogeneity. The model includes equilibrium reactions for aqueous species, kinetic reactions between the solid phases and aqueous constituents, and full coupling of porosity and permeability changes resulting from precipitation and dissolution reactions in porous media. In addition, a new permeability relationship is implemented in TOUGHREACT to examine the effects of geochemical reactions and density difference on plume migration in porous media. Generally, the evolutions in the concentrations of the aqueous phase are intimately related to the reaction-front dynamics. Plugging of the medium contributed to significant transients in patterns of flow and mass transport.

Turbulent particle transport in streams: can exponential settling be reconciled with fluid mechanics?

Science.gov (United States)

McNair, James N; Newbold, J Denis

2012-05-07

Most ecological studies of particle transport in streams that focus on fine particulate organic matter or benthic invertebrates use the Exponential Settling Model (ESM) to characterize the longitudinal pattern of particle settling on the bed. The ESM predicts that if particles are released into a stream, the proportion that have not yet settled will decline exponentially with transport time or distance and will be independent of the release elevation above the bed. To date, no credible basis in fluid mechanics has been established for this model, nor has it been rigorously tested against more-mechanistic alternative models. One alternative is the Local Exchange Model (LEM), which is a stochastic advection-diffusion model that includes both longitudinal and vertical spatial dimensions and is based on classical fluid mechanics. The LEM predicts that particle settling will be non-exponential in the near field but will become exponential in the far field, providing a new theoretical justification for far-field exponential settling that is based on plausible fluid mechanics. We review properties of the ESM and LEM and compare these with available empirical evidence. Most evidence supports the prediction of both models that settling will be exponential in the far field but contradicts the ESM's prediction that a single exponential distribution will hold for all transport times and distances. Copyright © 2012 Elsevier Ltd. All rights reserved.

Suppression of glymphatic fluid transport in a mouse model of Alzheimer's disease.

Science.gov (United States)

Peng, Weiguo; Achariyar, Thiyagarajan M; Li, Baoman; Liao, Yonghong; Mestre, Humberto; Hitomi, Emi; Regan, Sean; Kasper, Tristan; Peng, Sisi; Ding, Fengfei; Benveniste, Helene; Nedergaard, Maiken; Deane, Rashid

2016-09-01

Glymphatic transport, defined as cerebrospinal fluid (CSF) peri-arterial inflow into brain, and interstitial fluid (ISF) clearance, is reduced in the aging brain. However, it is unclear whether glymphatic transport affects the distribution of soluble Aβ in Alzheimer's disease (AD). In wild type mice, we show that Aβ40 (fluorescently labeled Aβ40 or unlabeled Aβ40), was distributed from CSF to brain, via the peri-arterial space, and associated with neurons. In contrast, Aβ42 was mostly restricted to the peri-arterial space due mainly to its greater propensity to oligomerize when compared to Aβ40. Interestingly, pretreatment with Aβ40 in the CSF, but not Aβ42, reduced CSF transport into brain. In APP/PS1 mice, a model of AD, with and without extensive amyloid-β deposits, glymphatic transport was reduced, due to the accumulation of toxic Aβ species, such as soluble oligomers. CSF-derived Aβ40 co-localizes with existing endogenous vascular and parenchymal amyloid-β plaques, and thus, may contribute to the progression of both cerebral amyloid angiopathy and parenchymal Aβ accumulation. Importantly, glymphatic failure preceded significant amyloid-β deposits, and thus, may be an early biomarker of AD. By extension, restoring glymphatic inflow and ISF clearance are potential therapeutic targets to slow the onset and progression of AD. Copyright © 2016 Elsevier Inc. All rights reserved.

SWIFT, 3-D Fluid Flow, Heat Transfer, Decay Chain Transport in Geological Media

International Nuclear Information System (INIS)

Cranwell, R.M.; Reeves, M.

2003-01-01

1 - Description of problem or function: SWIFT solves the coupled or individual equations governing fluid flow, heat transport, brine displacement, and radionuclide displacement in geologic media. Fluid flow may be transient or steady-state. One, two, or three dimensions are available and transport of radionuclides chains is possible. 4. Method of solution: Finite differencing is used to discretize the partial differential equations in space and time. The user may choose centered or backward spatial differencing, coupled with either central or backward temporal differencing. The matrix equations may be solved iteratively (two line successive-over-relaxation) or directly (special matrix banding and Gaussian elimination). 5. Restrictions on the complexity of the problem: On the CDC7600 in direct solution mode, the maximum number of grid blocks allowed is approximately 1400

Proceedings of the Fifth Microgravity Fluid Physics and Transport Phenomena Conference

Science.gov (United States)

Singh, Bhim S. (Editor)

2000-01-01

The Fifth Microgravity Fluid Physics and Transport Phenomena Conference provided the scientific community the opportunity to view the current scope of the Microgravity Fluid Physics and Transport Phenomena Program and research opportunities and plans for the near future. Consistent with the conference theme "Microgravity Research an Agency-Wide Asset" the conference focused not only on fundamental research but also on applications of this knowledge towards enabling future space exploration missions. The conference included 14 invited plenary talks, 61 technical paper presentations, 61 poster presentations, exhibits and a forum on emerging research themes focusing on nanotechnology and biofluid mechanics. This web-based proceeding includes the presentation and poster charts provided by the presenters of technical papers and posters that were scanned at the conference site. Abstracts of all the papers and posters are included and linked to the presentations charts. The invited and plenary speakers were not required to provide their charts and are generally not available for scanning and hence not posted. The conference program is also included.

IPROP simulations of the GAMBLE II proton transport experiment

International Nuclear Information System (INIS)

Welch, D.R.

1993-01-01

The author has simulated the proton transport of the 6-kA, 1-MV GAMBLE II experiment using a modified version of the IPROP particle-in-cell code. IPROP now uses a hybrid model in which plasma electrons are divided into high-energy macro particle and thermal-fluid components. This model includes open-quotes knock-onclose quotes bound-electron collision and runaway sources for high-energy electrons. Using IPROP, the authors has calculated net currents in reasonable agreement with the experiment ranging from 5-11% of the total current in pressures from 0.25-4 torr helium. In the simulations, the pinch current sample by the 1.5-cm beam was 2-3 times larger than the net current at 4 cm radius. The attenuation of net current at larger radii was the result of a highly-conductive energetic component of plasma electrons surrounding the beam. Having benchmarked IPROP against experiment, the author has examined higher-current ion beams with respect to possible transport for inertial confinement fusion

An automated fluid-transport device for a microfluidic system.

Science.gov (United States)

Feng, Jun; Yang, Xiu-Juan; Li, Xin-Chun; Yang, Hui; Chen, Zuan-Guang

2011-01-01

An automated fluid-transport device for a chip-based capillary electrophoresis system has been developed. The device mainly consists of six peristaltic micropumps, two vacuum micropumps, microvalves, multi-way joints, titanium tubes, and a macro-to-micro connector. Various solutions used for the cleaning and activation of chip channels, and electrophoresis separation, are allowed to automatically transport to chip reservoirs by the electric control module. The performance of the whole system was characterized by the analysis of fluorescein sodium using chip electrophoresis with LED-induced fluorescence detection. The peak-height variation (RSD) was 3.8% in six cycles of analyses. Additionally, compared with conventional manual operation, the developed device can spare 60% time for chip pretreatment. This microdevice offers high-efficiency pretreatment for microchips, thereby resulting in a remarkable improvement of analytical capacity for batch samples.

Point of net vapor generation and vapor void fraction in subcooled boiling

International Nuclear Information System (INIS)

Saha, P.; Zuber, N.

1974-01-01

An analysis is presented directed at predicting the point of net vapor generation and vapor void fraction in subcooled boiling. It is shown that the point of net vapor generation depends upon local conditions--thermal and fluid dynamic. Thus, at low mass flow rates the net vapor generation is determined by thermal conditions, whereas at high mass flow rates the phenomenon is hydrodynamically controlled. Simple criteria are derived which can be used to predict these local conditions for net vapor generation. These criteria are used to determine the vapor void fraction is subcooled boiling. Comparison between the results predicted by this analysis and experimental data presently available shows good agreement for wide range of operating conditions, fluids and geometries. (U.S.)

Numerical study on the hydrodynamic characteristics of biofouled full-scale net cage

Science.gov (United States)

Bi, Chun-wei; Zhao, Yun-peng; Dong, Guo-hai

2015-06-01

The effect of biofouling on the hydrodynamic characteristics of the net cage is of particular interest as biofouled nettings can significantly reduce flow of well-oxygenated water reaching the stocked fish. For computational efficiency, the porous-media fluid model is proposed to simulate flow through the biofouled plane net and full-scale net cage. The porous coefficients of the porous-media fluid model can be determined from the quadratic-function relationship between the hydrodynamic forces on a plane net and the flow velocity using the least squares method. In this study, drag forces on and flow fields around five plane nets with different levels of biofouling are calculated by use of the proposed model. The numerical results are compared with the experimental data of Swift et al. (2006) and the effectiveness of the numerical model is presented. On that basis, flow through full-scale net cages with the same level of biofouling as the tested plane nets are modeled. The flow fields inside and around biofouled net cages are analyzed and the drag force acting on a net cage is estimated by a control volume analysis method. According to the numerical results, empirical formulas of reduction in flow velocity and load on a net cage are derived as function of drag coefficient of the corresponding biofouled netting.

Parallel unstructured mesh optimisation for 3D radiation transport and fluids modelling

International Nuclear Information System (INIS)

Gorman, G.J.; Pain, Ch. C.; Oliveira, C.R.E. de; Umpleby, A.P.; Goddard, A.J.H.

2003-01-01

In this paper we describe the theory and application of a parallel mesh optimisation procedure to obtain self-adapting finite element solutions on unstructured tetrahedral grids. The optimisation procedure adapts the tetrahedral mesh to the solution of a radiation transport or fluid flow problem without sacrificing the integrity of the boundary (geometry), or internal boundaries (regions) of the domain. The objective is to obtain a mesh which has both a uniform interpolation error in any direction and the element shapes are of good quality. This is accomplished with use of a non-Euclidean (anisotropic) metric which is related to the Hessian of the solution field. Appropriate scaling of the metric enables the resolution of multi-scale phenomena as encountered in transient incompressible fluids and multigroup transport calculations. The resulting metric is used to calculate element size and shape quality. The mesh optimisation method is based on a series of mesh connectivity and node position searches of the landscape defining mesh quality which is gauged by a functional. The mesh modification thus fits the solution field(s) in an optimal manner. The parallel mesh optimisation/adaptivity procedure presented in this paper is of general applicability. We illustrate this by applying it to a transient CFD (computational fluid dynamics) problem. Incompressible flow past a cylinder at moderate Reynolds numbers is modelled to demonstrate that the mesh can follow transient flow features. (authors)

Exact and Numerical Solutions of a Spatially-Distributed Mathematical Model for Fluid and Solute Transport in Peritoneal Dialysis

Directory of Open Access Journals (Sweden)

Roman Cherniha

2016-06-01

Full Text Available The nonlinear mathematical model for solute and fluid transport induced by the osmotic pressure of glucose and albumin with the dependence of several parameters on the hydrostatic pressure is described. In particular, the fractional space available for macromolecules (albumin was used as a typical example and fractional fluid void volume were assumed to be different functions of hydrostatic pressure. In order to find non-uniform steady-state solutions analytically, some mathematical restrictions on the model parameters were applied. Exact formulae (involving hypergeometric functions for the density of fluid flux from blood to tissue and the fluid flux across tissues were constructed. In order to justify the applicability of the analytical results obtained, a wide range of numerical simulations were performed. It was found that the analytical formulae can describe with good approximation the fluid and solute transport (especially the rate of ultrafiltration for a wide range of values of the model parameters.

Flapping motion and force generation in a viscoelastic fluid

Science.gov (United States)

Normand, Thibaud; Lauga, Eric

2008-12-01

In a variety of biological situations, swimming cells have to move through complex fluids. Similarly, mucociliary clearance involves the transport of polymeric fluids by beating cilia. Here, we consider the extent to which complex fluids could be exploited for force generation on small scales. We consider a prototypical reciprocal motion (i.e., identical under time-reversal symmetry): the periodic flapping of a tethered semi-infinite plane. In the Newtonian limit, such motion cannot be used for force generation according to Purcell’s scallop theorem. In a polymeric fluid (Oldroyd-B, and its generalization), we show that this is not the case and calculate explicitly the forces on the flapper for small-amplitude sinusoidal motion. Three setups are considered: a flapper near a wall, a flapper in a wedge, and a two-dimensional scalloplike flapper. In all cases, we show that at quadratic order in the oscillation amplitude, the tethered flapping motion induces net forces, but no average flow. Our results demonstrate therefore that the scallop theorem is not valid in polymeric fluids. The reciprocal component of the movement of biological appendages such as cilia can thus generate nontrivial forces in polymeric fluid such as mucus, and normal-stress differences can be exploited as a pure viscoelastic force generation and propulsion method.

Protective effect of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on irradiation-induced inhibition of intestinal transport function

International Nuclear Information System (INIS)

Chen, T.S.; Ando, M.

1983-01-01

The purpose of this study was to investigate the protective effect of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on whole-body irradiation-induced inhibition of intestinal transport function. The jejunal transport of fluid and sugars was studied in male Swiss-Webster mice before and 3 days after whole-body irradiation (1000 rads). The rates of glucose and water transport were decreased by 86 and 70%, respectively, in irradiated animals. However, the rate of transport of 3-O-methyl-D-glucose (3MG) was not affected. In mice receiving WR-2721 (500 mg/kg, ip) 15 to 30 min prior to whole-body irradiation, net water flux was unaffected and the rate of D-glucose transport was decreased only 8%. WR-2721 administered alone (500 mg/kg, ip) had no effect on either D-glucose transport or net water flux across the jejunal mucosa. The results suggest that WR-2721 protects against irradiation-induced inhibition of some intestinal transport functions

One-dimensional fluid model for transport in divertor and limiter tokamak scrape-off layers

International Nuclear Information System (INIS)

Lipschultz, B.

1983-11-01

Single-fluid transport in the plasma scrape-off layer is modeled for poloidal divertor and mechanically limited discharges. This numerical model is one-dimensional along a field line and time-independent. Conductive and convective transport, as well as impurity and neutral source (sink) terms are included. A simple shooting method technique is used for obtaining solutions. Results are shown for the case of the proposed Alcator DCT tokamak

Changes of peritoneal transport parameters with time on dialysis: assessment with sequential peritoneal equilibration test.

Science.gov (United States)

Waniewski, Jacek; Antosiewicz, Stefan; Baczynski, Daniel; Poleszczuk, Jan; Pietribiasi, Mauro; Lindholm, Bengt; Wankowicz, Zofia

2017-10-27

Sequential peritoneal equilibration test (sPET) is based on the consecutive performance of the peritoneal equilibration test (PET, 4-hour, glucose 2.27%) and the mini-PET (1-hour, glucose 3.86%), and the estimation of peritoneal transport parameters with the 2-pore model. It enables the assessment of the functional transport barrier for fluid and small solutes. The objective of this study was to check whether the estimated model parameters can serve as better and earlier indicators of the changes in the peritoneal transport characteristics than directly measured transport indices that depend on several transport processes. 17 patients were examined using sPET twice with the interval of about 8 months (230 ± 60 days). There was no difference between the observational parameters measured in the 2 examinations. The indices for solute transport, but not net UF, were well correlated between the examinations. Among the estimated parameters, a significant decrease between the 2 examinations was found only for hydraulic permeability LpS, and osmotic conductance for glucose, whereas the other parameters remained unchanged. These fluid transport parameters did not correlate with D/P for creatinine, although the decrease in LpS values between the examinations was observed mostly for patients with low D/P for creatinine. We conclude that changes in fluid transport parameters, hydraulic permeability and osmotic conductance for glucose, as assessed by the pore model, may precede the changes in small solute transport. The systematic assessment of fluid transport status needs specific clinical and mathematical tools beside the standard PET tests.

Thermal-chemical-mechanical feedback during fluid-rock interactions: Implications for chemical transport and scales of equilibria in the crust

International Nuclear Information System (INIS)

Dutrow, Barbara

2008-01-01

Our research evaluates the hypothesis that feedback amongst thermal-chemical-mechanical processes operative in fluid-rock systems alters the fluid flow dynamics of the system which, in turn, affects chemical transport and temporal and spatial scales of equilibria, thus impacting the resultant mineral textural development of rocks. Our methods include computational experimentation and detailed analyses of fluid-infiltrated rocks from well-characterized terranes. This work focuses on metamorphic rocks and hydrothermal systems where minerals and their textures are utilized to evaluate pressure (P), temperature (T), and time (t) paths in the evolution of mountain belts and ore deposits, and to interpret tectonic events and the timing of these events. Our work on coupled processes also extends to other areas where subsurface flow and transport in porous media have consequences such as oil and gas movement, geothermal system development, transport of contaminants, nuclear waste disposal, and other systems rich in fluid-rock reactions. Fluid-rock systems are widespread in the geologic record. Correctly deciphering the products resulting from such systems is important to interpreting a number of geologic phenomena. These systems are characterized by complex interactions involving time-dependent, non-linear processes in heterogeneous materials. While many of these interactions have been studied in isolation, they are more appropriately analyzed in the context of a system with feedback. When one process impacts another process, time and space scales as well as the overall outcome of the interaction can be dramatically altered. Our goals to test this hypothesis are: to develop and incorporate algorithms into our 3D heat and mass transport code to allow the effects of feedback to be investigated numerically, to analyze fluid infiltrated rocks from a variety of terranes at differing P-T conditions, to identify subtle features of the infiltration of fluids and/or feedback, and

Cisterna magna microdialysis of 22Na to evaluate ion transport and cerebrospinal fluid dynamics

International Nuclear Information System (INIS)

Knuckey, N.W.; Fowler, A.G.; Johanson, C.E.; Nashold, J.R.; Epstein, M.H.

1991-01-01

Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting 22 Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of 22 Na dialyzed. This hypothesis is supported by the 22 Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the 22 Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system

The application of fluid structure interaction techniques within finite element analyses of water-filled transport flasks

International Nuclear Information System (INIS)

Smith, C.; Stojko, S.

2004-01-01

Historically, Finite Element (FE) analyses of water-filled transport flasks and their payloads have been carried out assuming a dry environment, mainly due to a lack of robust Fluid Structure Interaction (FSI) modelling techniques. Also it has been accepted within the RAM transport industry that the presence of water would improve the impact withstand capability of dropped payloads within containers. In recent years the FE community has seen significant progress and improvement in FSI techniques. These methods have been utilised to investigate the effects of a wet environment on payload behaviour for the regulatory drop test within a recent transport licence renewal application. Fluid flow and pressure vary significantly during a wet impact and the effects on the contents become complex when water is incorporated into the flask analyses. Modelling a fluid environment within the entire flask is considered impractical; hence a good understanding of the FSI techniques and assumptions regarding fluid boundaries is required in order to create a representative FSI model. Therefore, a Verification and Validation (V and V) exercise was undertaken to underpin the FSI techniques eventually utilised. A number of problems of varying complexity have been identified to test the FSI capabilities of the explicit code LS-DYNA, which is used in the extant dry container impact analyses. RADIOSS explicit code has been used for comparison, to provide further confidence in LS-DYNA predictions. Various methods of modelling fluid are tested, and the relative advantages and limitations of each method and FSI coupling approaches are discussed. Results from the V and V problems examined provided sufficient confidence that FSI effects within containers can be accurately modelled

A mixture theory model of fluid and solute transport in the microvasculature of normal and malignant tissues. I. Theory.

Science.gov (United States)

Schuff, M M; Gore, J P; Nauman, E A

2013-05-01

In order to better understand the mechanisms governing transport of drugs, nanoparticle-based treatments, and therapeutic biomolecules, and the role of the various physiological parameters, a number of mathematical models have previously been proposed. The limitations of the existing transport models indicate the need for a comprehensive model that includes transport in the vessel lumen, the vessel wall, and the interstitial space and considers the effects of the solute concentration on fluid flow. In this study, a general model to describe the transient distribution of fluid and multiple solutes at the microvascular level was developed using mixture theory. The model captures the experimentally observed dependence of the hydraulic permeability coefficient of the capillary wall on the concentration of solutes present in the capillary wall and the surrounding tissue. Additionally, the model demonstrates that transport phenomena across the capillary wall and in the interstitium are related to the solute concentration as well as the hydrostatic pressure. The model is used in a companion paper to examine fluid and solute transport for the simplified case of an axisymmetric geometry with no solid deformation or interconversion of mass.

Studies on the mechanism of action of enterotoxin-induced fluid secretion in the gut

International Nuclear Information System (INIS)

Schirgi-Degen, A.

1992-12-01

The mechanism of action of Clostridium difficile enterotoxin A (CA), of Escherichia coli enterotoxin (STa) and of cholera toxin (CT), which are known to cause severe diarrhea, were studied in a preparation of ligated jejunal loops of anesthetized rats in vivo. The toxins were administered intraluminally. Pharmacological agents, which were tested for their potency to influence toxin-related effects, were administered subcutaneously. Net fluid transport was determined gravimetrically, prostaglandin (PG) E 2 -output into the lumen, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) contents in the mucosa were measured by radioimmunoassay, serotonin-(5-HT)-output into the lumen was determined by high performance liquid chromatography. The histopathological effects of CA and CT were examined by light- and scanning electron microscopy. All three toxins caused net fluid secretion (FS). 5-HT 2 -(ketanserin) and 5-HT 3 -receptor antagonists (tropisetron, ondansetron, granisetron) dose-dependently reduced or abolished CT- and STa-induced net FS, CA-induced net FS was not influenced. Indomethacin reduced CA-, CT- and STa-induced net FS. Elevation of PGE 2 -output occurred after exposure to CA and CT and was reduced by indomethacin. CA caused severe histopathological lesions and also CT time-dependently caused morphological changes, which may take part in the secretory response. It is concluded that 5-HT, using both 5-HT 2 - and 5-HT 3 -receptors, mediates CT- and STa, but not CA-induced FS. PGE 2 is involved in FS caused by all three toxins. CAMP and cGMP are presumedly no causative mediators of toxin-induced FS

Modelling of reactive fluid transport in deformable porous rocks

Science.gov (United States)

Yarushina, V. M.; Podladchikov, Y. Y.

2009-04-01

One outstanding challenge in geology today is the formulation of an understanding of the interaction between rocks and fluids. Advances in such knowledge are important for a broad range of geologic settings including partial melting and subsequent migration and emplacement of a melt into upper levels of the crust, or fluid flow during regional metamorphism and metasomatism. Rock-fluid interaction involves heat and mass transfer, deformation, hydrodynamic flow, and chemical reactions, thereby necessitating its consideration as a complex process coupling several simultaneous mechanisms. Deformation, chemical reactions, and fluid flow are coupled processes. Each affects the others. Special effort is required for accurate modelling of the porosity field through time. Mechanical compaction of porous rocks is usually treated under isothermal or isoentropic simplifying assumptions. However, joint consideration of both mechanical compaction and reactive porosity alteration requires somewhat greater than usual care about thermodynamic consistency. Here we consider the modelling of multi-component, multi-phase systems, which is fundamental to the study of fluid-rock interaction. Based on the conservation laws for mass, momentum, and energy in the form adopted in the theory of mixtures, we derive a thermodynamically admissible closed system of equations describing the coupling of heat and mass transfer, chemical reactions, and fluid flow in a deformable solid matrix. Geological environments where reactive transport is important are located at different depths and accordingly have different rheologies. In the near surface, elastic or elastoplastic properties would dominate, whereas viscoplasticity would have a profound effect deeper in the lithosphere. Poorly understood rheologies of heterogeneous porous rocks are derived from well understood processes (i.e., elasticity, viscosity, plastic flow, fracturing, and their combinations) on the microscale by considering a

Transport equations, Level Set and Eulerian mechanics. Application to fluid-structure coupling

International Nuclear Information System (INIS)

Maitre, E.

2008-11-01

My works were devoted to numerical analysis of non-linear elliptic-parabolic equations, to neutron transport equation and to the simulation of fabrics draping. More recently I developed an Eulerian method based on a level set formulation of the immersed boundary method to deal with fluid-structure coupling problems arising in bio-mechanics. Some of the more efficient algorithms to solve the neutron transport equation make use of the splitting of the transport operator taking into account its characteristics. In the present work we introduced a new algorithm based on this splitting and an adaptation of minimal residual methods to infinite dimensional case. We present the case where the velocity space is of dimension 1 (slab geometry) and 2 (plane geometry) because the splitting is simpler in the former

Chemical processes related to net ozone tendencies in the free troposphere

Science.gov (United States)

Bozem, Heiko; Butler, Tim M.; Lawrence, Mark G.; Harder, Hartwig; Martinez, Monica; Kubistin, Dagmar; Lelieveld, Jos; Fischer, Horst

2017-09-01

Ozone (O3) is an important atmospheric oxidant, a greenhouse gas, and a hazard to human health and agriculture. Here we describe airborne in situ measurements and model simulations of O3 and its precursors during tropical and extratropical field campaigns over South America and Europe, respectively. Using the measurements, net ozone formation/destruction tendencies are calculated and compared to 3-D chemistry-transport model simulations. In general, observation-based net ozone tendencies are positive in the continental boundary layer and the upper troposphere at altitudes above ˜ 6 km in both environments. On the other hand, in the marine boundary layer and the middle troposphere, from the top of the boundary layer to about 6-8 km altitude, net O3 destruction prevails. The ozone tendencies are controlled by ambient concentrations of nitrogen oxides (NOx). In regions with net ozone destruction the available NOx is below the threshold value at which production and destruction of O3 balance. While threshold NO values increase with altitude, in the upper troposphere NOx concentrations are generally higher due to the integral effect of convective precursor transport from the boundary layer, downward transport from the stratosphere and NOx produced by lightning. Two case studies indicate that in fresh convective outflow of electrified thunderstorms net ozone production is enhanced by a factor 5-6 compared to the undisturbed upper tropospheric background. The chemistry-transport model MATCH-MPIC generally reproduces the pattern of observation-based net ozone tendencies but mostly underestimates the magnitude of the net tendency (for both net ozone production and destruction).

Fluid simulation of beryllium transport in the ITER gaseous divertor

International Nuclear Information System (INIS)

Knoll, D.A.; Campbell, R.B.; McHugh, P.R.

1994-01-01

The transport of either intrinsic or injected impurities will play a crucial role in the energy loss mechanisms in the ITER gaseous/cold plasma target divertor. Both 1-D and 2-D multi-charge state fluid codes are used to model the transport of beryllium in the ITER SOL. Our major conclusion is that in order to model the containment of impurities, the background flow field must be known in detail. Comparing 1-D and 2-D solutions, hydrogen flow reversal plays an important role in the entrainment process. Further, the flow of particles from the core plasma also has a strong impact on the resultant entrainment of the impurities in both 1-D and 2-D. It is imperative that those components of poloidal velocity due to E x B and diamagnetic drifts be included in the models. (orig.)

Multiscale modeling of fluid flow and mass transport

Science.gov (United States)

Masuoka, K.; Yamamoto, H.; Bijeljic, B.; Lin, Q.; Blunt, M. J.

2017-12-01

In recent years, there are some reports on a simulation of fluid flow in pore spaces of rocks using Navier-Stokes equations. These studies mostly adopt a X-ray CT to create 3-D numerical grids of the pores in micro-scale. However, results may be of low accuracy when the rock has a large pore size distribution, because pores, whose size is smaller than resolution of the X-ray CT may be neglected. We recently found out by tracer tests in a laboratory using a brine saturated Ryukyu limestone and inject fresh water that a decrease of chloride concentration took longer time. This phenomenon can be explained due to weak connectivity of the porous networks. Therefore, it is important to simulate entire pore spaces even those of very small sizes in which diffusion is dominant. We have developed a new methodology for multi-level modeling for pore scale fluid flow in porous media. The approach is to combine pore-scale analysis with Darcy-flow analysis using two types of X-ray CT images in different resolutions. Results of the numerical simulations showed a close match with the experimental results. The proposed methodology is an enhancement for analyzing mass transport and flow phenomena in rocks with complicated pore structure.

Workshop on Critical Issues in Microgravity Fluids, Transport, and Reaction Processes in Advanced Human Support Technology

Science.gov (United States)

Chiaramonte, Francis P.; Joshi, Jitendra A.

2004-01-01

This workshop was designed to bring the experts from the Advanced Human Support Technologies communities together to identify the most pressing and fruitful areas of research where success hinges on collaborative research between the two communities. Thus an effort was made to bring together experts in both advanced human support technologies and microgravity fluids, transport and reaction processes. Expertise was drawn from academia, national laboratories, and the federal government. The intent was to bring about a thorough exchange of ideas and develop recommendations to address the significant open design and operation issues for human support systems that are affected by fluid physics, transport and reaction processes. This report provides a summary of key discussions, findings, and recommendations.

Glymphatic fluid transport controls paravascular clearance of AAV vectors from the brain

Science.gov (United States)

Murlidharan, Giridhar; Crowther, Andrew; Reardon, Rebecca A.; Song, Juan

2016-01-01

Adeno-associated viruses (AAV) are currently being evaluated in clinical trials for gene therapy of CNS disorders. However, host factors that influence the spread, clearance, and transduction efficiency of AAV vectors in the brain are not well understood. Recent studies have demonstrated that fluid flow mediated by aquaporin-4 (AQP4) channels located on astroglial end feet is essential for exchange of solutes between interstitial and cerebrospinal fluid. This phenomenon, which is essential for interstitial clearance of solutes from the CNS, has been termed glial-associated lymphatic transport or glymphatic transport. In the current study, we demonstrate that glymphatic transport profoundly affects various aspects of AAV gene transfer in the CNS. Altered localization of AQP4 in aged mouse brains correlated with significantly increased retention of AAV vectors in the parenchyma and reduced systemic leakage following ventricular administration. We observed a similar increase in AAV retention and transgene expression upon i.c.v. administration in AQP4–/– mice. Consistent with this observation, fluorophore-labeled AAV vectors showed markedly reduced flux from the ventricles of AQP4–/– mice compared with WT mice. These results were further corroborated by reduced AAV clearance from the AQP4-null brain, as demonstrated by reduced transgene expression and vector genome accumulation in systemic organs. We postulate that deregulation of glymphatic transport in aged and diseased brains could markedly affect the parenchymal spread, clearance, and gene transfer efficiency of AAV vectors. Assessment of biomarkers that report the kinetics of CSF flux in prospective gene therapy patients might inform variable treatment outcomes and guide future clinical trial design. PMID:27699236

SIMULATION OF NET INFILTRATION FOR MODERN AND POTENTIAL FUTURE CLIMATES

Energy Technology Data Exchange (ETDEWEB)

J.A. Heveal

2000-06-16

This Analysis/Model Report (AMR) describes enhancements made to the infiltration model documented in Flint et al. (1996) and documents an analysis using the enhanced model to generate spatial and temporal distributions over a model domain encompassing the Yucca Mountain site, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone, the average depth below the ground surface (at a given location) from which water is removed by evapotranspiration. The estimates of net infiltration are used for defining the upper boundary condition for the site-scale 3-dimensional Unsaturated-Zone Ground Water Flow and Transport (UZ flow and transport) Model (CRWMS M&O 2000a). The UZ flow and transport model is one of several process models abstracted by the Total System Performance Assessment model to evaluate expected performance of the potential repository at Yucca Mountain, Nevada, in terms of radionuclide transport (CRWMS M&O 1998). The net-infiltration model is important for assessing potential repository-system performance because output from this model provides the upper boundary condition for the UZ flow and transport model that is used to generate flow fields for evaluating potential radionuclide transport through the unsaturated zone. Estimates of net infiltration are provided as raster-based, 2-dimensional grids of spatially distributed, time-averaged rates for three different climate stages estimated as likely conditions for the next 10,000 years beyond the present. Each climate stage is represented using a lower bound, a mean, and an upper bound climate and corresponding net-infiltration scenario for representing uncertainty in the characterization of daily climate conditions for each climate stage, as well as potential climate variability within each climate stage. The set of nine raster grid maps provide spatially

SIMULATION OF NET INFILTRATION FOR MODERN AND POTENTIAL FUTURE CLIMATES

International Nuclear Information System (INIS)

J.A. Heveal

2000-01-01

This Analysis/Model Report (AMR) describes enhancements made to the infiltration model documented in Flint et al. (1996) and documents an analysis using the enhanced model to generate spatial and temporal distributions over a model domain encompassing the Yucca Mountain site, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone, the average depth below the ground surface (at a given location) from which water is removed by evapotranspiration. The estimates of net infiltration are used for defining the upper boundary condition for the site-scale 3-dimensional Unsaturated-Zone Ground Water Flow and Transport (UZ flow and transport) Model (CRWMS M and O 2000a). The UZ flow and transport model is one of several process models abstracted by the Total System Performance Assessment model to evaluate expected performance of the potential repository at Yucca Mountain, Nevada, in terms of radionuclide transport (CRWMS M and O 1998). The net-infiltration model is important for assessing potential repository-system performance because output from this model provides the upper boundary condition for the UZ flow and transport model that is used to generate flow fields for evaluating potential radionuclide transport through the unsaturated zone. Estimates of net infiltration are provided as raster-based, 2-dimensional grids of spatially distributed, time-averaged rates for three different climate stages estimated as likely conditions for the next 10,000 years beyond the present. Each climate stage is represented using a lower bound, a mean, and an upper bound climate and corresponding net-infiltration scenario for representing uncertainty in the characterization of daily climate conditions for each climate stage, as well as potential climate variability within each climate stage. The set of nine raster grid maps provide

Molecular Simulations As a Tool for Predicting Phase Equilibria and Transport Properties of Fluids Les simulations moléculaires comme outils pour prédire les équilibres de phases et les propriétés de transport des fluides

Directory of Open Access Journals (Sweden)

Fuchs A.

2006-12-01

Full Text Available koWe briefly review the molecular simulation methods which can be used to predict thermophysical properties of fluids and fluid mixtures. It is shown in this paper, on the one hand, how the Gibbs Ensemble Monte Carlo Method allows phase behavior predictions for real fluids under conditions for which experimental data are difficult or impossible to obtain. On the other hand, the molecular dynamics methods used for predicting transport properties of molecular fluids are described. Finally we discuss possible future applications of these methods. Dans cet article, nous passons brièvement en revue les méthodes de simulation moléculaire applicables à la prédiction des propriétés thermophysiques des fluides et des mélanges. Nous montrons, d'une part, comment la méthode de Monte-Carlo dans l'ensemble de Gibbs permet de prédire le comportement de phase de fluides réels dans des conditions telles que l'acquisition de données expérimentales serait difficile, voire impossible. D'autre part, nous décrivons les méthodes de dynamique moléculaire utilisées pour prédire les propriétés de transport de fluides moléculaires. Enfin, nous discutons le potentiel de ces méthodes pour les applications futures.

16 CFR 500.10 - Units of fluid measure, how expressed.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Units of fluid measure, how expressed. 500... UNDER SECTION 4 OF THE FAIR PACKAGING AND LABELING ACT § 500.10 Units of fluid measure, how expressed. (a) Use of the terms “net” or “net contents” is optional. (b) Declaration of net quantity of contents...

How to dip nectar: optimal time apportionment in natural viscous fluid transport

Science.gov (United States)

Wu, Jianing; Shi, Guanya; Zhao, Yiwei; Yan, Shaoze

2018-06-01

The mouthparts of some animals are highly evolved fluid transporters. Most honeybees dip viscous nectar in a cyclic fashion by using protrusible tongues with active hairs that can erect rhythmically. The glossal hairs flatten when the tongue extends into the nectar, and then erect outwards like an umbrella to catch nectar while retracting. This paper examines the potential capability of honeybees in allocating the duration of the tongue protraction and retraction phases for the sake of energy saving. A physical model is established to analyze energy consumption induced by viscous drag, considering tongue kinematics and variation of the surface profile in different phases of tongue movements. The results indicate that the theoretically optimal time apportionment ratio at which the energy consumption is the minimum, is directly related to the square root of the tongue’s diameter ratio between the protraction and retraction phase. Through dipping observations, we validate that the duration for the protraction and retraction phases show high accordance with the theoretical prediction. These findings not only broaden the insights into honeybee’s foraging strategy but inspire the design of high-performance microfluidic pumps with dynamic surfaces to transport viscous fluid.

Characterization of the Hanford 300 Area Burial Grounds. Task III: fluid transport and modeling

International Nuclear Information System (INIS)

Gee, G.W.; Simmons, C.S.

1979-08-01

In Task III, Fluid Transport and Modeling, a computer model was developed and applied to the 300 Area Burial Grounds to analyze the influence of potential evaporation and rainfall patterns on drainage. The model describes one-dimensional unsaturated flow. Fluid transport equations were evaluated to describe the driving forces of fluid flow. The data indicate that the major processes are evaporative drying, capillarity, and gravity flow. Thermally induced transport does not appear significant in the subsurface sediments of the area. Several empirical evaporation methods are available for assessing potential evaporation/evapotranspiration. Four methods were used with the unsaturated flow model. Ultimately, the Blaney-Criddle method was chosen for subsequent simulation examples because it relies only on the climatic data available and gave results comparable to the other methods tested. Simulations showed that a dry layer formation is important in controlling the soil-water balance in the profile. The surface dry layer acts as a mulch to retard the evaporative water losses and increase water storage. The most important climatic factor in determining drainage appears to be yearly rainfall distribution. When rainfall is distributed in fall or winter, during periods of low potential evaporation, both water storage and drainage are increased. Summer showers, on the other hand, were shown to add little to the annual water storage. Rainfall occurring in one year influences the subsequent annual drainage for several succeeding years because of annual changes in water storage capacity and the transient nature of unsaturated flow in the storage zone. 47 figures, 9 tables

Selective pumping in a network: insect-style microscale flow transport

International Nuclear Information System (INIS)

Aboelkassem, Yasser; Staples, Anne E

2013-01-01

A new paradigm for selective pumping of fluids in a complex network of channels in the microscale flow regime is presented. The model is inspired by internal flow distributions produced by the rhythmic wall contractions observed in many insect tracheal networks. The approach presented here is a natural extension of previous two-dimensional modeling of insect-inspired microscale flow transport in a single channel, and aims to manipulate fluids efficiently in microscale networks without the use of any mechanical valves. This selective pumping approach enables fluids to be transported, controlled and precisely directed into a specific branch in a network while avoiding other possible routes. In order to present a quantitative analysis of the selective pumping approach presented here, the velocity and pressure fields and the time-averaged net flow that are induced by prescribed wall contractions are calculated numerically using the method of fundamental solutions. More specifically, the Stokeslets-meshfree method is used in this study to solve the Stokes equations that govern the flow motions in a network with moving wall contractions. The results presented here might help in understanding some features of the insect respiratory system function and guide efforts to fabricate novel microfluidic devices for flow transport and mixing, and targeted drug delivery applications. (paper)

Peristaltic transport of Bingham plastic fluid considering magnetic field, Soret and Dufour effects

Directory of Open Access Journals (Sweden)

T. Hayat

Full Text Available Current attempt addresses the peristaltic transport of Bingham plastic fluid under the influence of magnetic force. Space dependent viscosity is considered. Novel Soret and Dufour effects are retained in the mathematical model. Problem formulation is presented through the conventional lubrication approach. Series solutions of the arising non-linear problem are developed via regular perturbation approach. Special attention is given to the role of embedded parameters on the axial velocity, temperature, concentration and pressure distributions. Furthermore the numerical solution of pressure rise per wavelength is obtained through numerical integration because its analytical solution seems impossible. Keywords: Bingham fluid, Variable viscosity, MHD and Joule heating, Soret and Dufour effects

Uncertainty in forecasting breakthrough of fluid transported through fractures

International Nuclear Information System (INIS)

Horne, R.N.

1989-01-01

Tracer experiments in geothermal reservoirs emphasize the very great variability in rates of fluid movement through fractured rocks. This variability extends from the 10-meter to the kilometer-length scale. Thus tracer returns have been observed at some locations within hours at distances of up to 1 kilometer from the injection point, while other much nearer locations in the same formation do not observe the tracer until much later. In addition, transport rates have sometimes been extremely fast (up to 100 m/hr) even over such distances. This paper discusses the conclusions reached after compiling the results of a large number of tracer tests in several different fractured reservoirs. It is evident in some cases that large-scale geological features, such as faults, are responsible for the variations in tracer return time. In other cases, there is no clear physical description that explains the differences. These results suggest that there will be no a priori way of forecasting transport rates in fractured systems without performing a tracer test

Two-fluid description of wave-particle interactions in strong Buneman turbulence

Energy Technology Data Exchange (ETDEWEB)

Che, H. [NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

2014-06-15

To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.

Two-fluid description of wave-particle interactions in strong Buneman turbulence

Science.gov (United States)

Che, H.

2014-06-01

To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.

Two-fluid description of wave-particle interactions in strong Buneman turbulence

International Nuclear Information System (INIS)

Che, H.

2014-01-01

To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability

Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model

Science.gov (United States)

Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P.; Russell, MacKenzie R.; Jones, Robert M.; King, Matt; Betterton, Eric A.; Sáez, A. Eduardo

2014-01-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition. PMID:25621085

Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model.

Science.gov (United States)

Stovern, Michael; Felix, Omar; Csavina, Janae; Rine, Kyle P; Russell, MacKenzie R; Jones, Robert M; King, Matt; Betterton, Eric A; Sáez, A Eduardo

2014-09-01

Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition.

The rheology of non-suspended sediment transport mediated by a Newtonian fluid

Science.gov (United States)

Pähtz, Thomas; Durán, Orencio

2017-04-01

Using a coupled DEM/RANS numerical model of non-suspended sediment transport in a Newtonian fluid (Durán et al., POF 103306, 2012), we find that the gas-like part of the granular transport flow can be described by a universal condition that constrains the average geometry of interparticle collisions. We show that this condition corresponds to a constant sliding friction coefficient μ at an appropriately defined bed surface, thus explaining the success of Bagnold's old idea to describe the sediment transport in analogy to sliding friction. We are currently exploring whether this rheology applies to gas-like granular flows in general. We further find a transition of the gas-like flow to either a solid-like flow (solid-to-gas transition), which is typical for aeolian sediment transport ('saltation'), or a liquid-like flow (liquid-to-gas transition), which is typical for subaqueous sediment transport ('bedload'). The transition occurs at about the location of maximal particle collision frequency. If there is a liquid-like flow below the transition, we find that it can be described by a μ(I) rheology, where I is the visco-intertial number, an appropriately defined average of the viscous and intertial number.

Microgravity Fluids for Biology, Workshop

Science.gov (United States)

Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.

2013-01-01

Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.

Monocarboxylate transporter 4, associated with the acidification of synovial fluid, is a novel therapeutic target for inflammatory arthritis.

Science.gov (United States)

Fujii, Wataru; Kawahito, Yutaka; Nagahara, Hidetake; Kukida, Yuji; Seno, Takahiro; Yamamoto, Aihiro; Kohno, Masataka; Oda, Ryo; Taniguchi, Daigo; Fujiwara, Hiroyoshi; Ejima, Akika; Kishida, Tsunao; Mazda, Osam; Ashihara, Eishi

2015-11-01

Synovial fluid pH is decreased in patients with rheumatoid arthritis (RA); however, the underlying mechanisms are unclear. We undertook this study to examine the mechanism by which synovial fluid pH is regulated and to explore the possibility of a therapeutic strategy by manipulating this mechanism. We determined the pH and lactate concentration in synovial fluid from 16 RA patients. Cultured synovial fibroblasts (SFs) from the inflamed joints of 9 RA patients (RASFs) were examined for the expression of ion transporters that regulate intracellular and extracellular pH. The ion transporter up-regulated in RASF lines was then suppressed in RASFs by small interfering RNA (siRNA), and the effect of transfection on viability and proliferation was investigated. Finally, we examined the therapeutic effect of electrotransfer of monocarboxylate transporter 4 (MCT4)-specific siRNA into the articular synovium of mice with collagen-induced arthritis (CIA). Synovial fluid pH correlated inversely with both the Disease Activity Score in 28 joints using the C-reactive protein level and the synovial fluid lactate levels. RASFs exhibited up-regulated transcription of MCT4 messenger RNA. MCT4 exported intracellular lactate into the extracellular space. RASFs had significantly higher MCT4 protein levels than did SFs from patients with osteoarthritis. Knockdown of MCT4 induced intrinsic apoptosis of RASFs, thereby inhibiting their proliferation. Moreover, electrotransfer of MCT4-specific siRNA into the articular synovium of mice with CIA significantly reduced the severity of arthritis. RA activity correlated with decreased synovial fluid pH. This may be due to increased MCT4 expression in RASFs. Silencing MCT4 induced apoptosis in RASFs and reduced the severity of CIA, suggesting that MCT4 is a potential therapeutic target for inflammatory arthritis. © 2015, American College of Rheumatology.

Generalized fluid equations for parallel transport in collisional to weakly collisional plasmas

International Nuclear Information System (INIS)

Zawaideh, E.; Najmabadi, F.; Conn, R.W.

1986-01-01

A new set of two-fluid equations that are valid from collisional to weakly collisional limits is derived. Starting from gyrokinetic equations in flux coordinates with no zero-order drifts, a set of moment equations describing plasma transport along the field lines of a space- and time-dependent magnetic field is derived. No restriction on the anisotropy of the ion distribution function is imposed. In the highly collisional limit, these equations reduce to those of Braginskii, while in the weakly collisional limit they are similar to the double adiabatic or Chew, Goldberger, and Low (CGL) equations [Proc. R. Soc. London, Ser. A 236, 112 (1956)]. The new set of equations also exhibits a physical singularity at the sound speed. This singularity is used to derive and compute the sound speed. Numerical examples comparing these equations with conventional transport equations show that in the limit where the ratio of the mean free path lambda to the scale length of the magnetic field gradient L/sub B/ approaches zero, there is no significant difference between the solution of the new and conventional transport equations. However, conventional fluid equations, ordinarily expected to be correct to the order (lambda/L/sub B/) 2 , are found to have errors of order (lambda/L/sub u/) 2 = (lambda/L/sub B/) 2 /(1-M 2 ) 2 , where L/sub u/ is the scale length of the flow velocity gradient and M is the Mach number. As such, the conventional equations may contain large errors near the sound speed (Mroughly-equal1)

Generalized fluid equations for parallel transport in collisional to weakly collisional plasmas

International Nuclear Information System (INIS)

Zawaideh, E.S.

1985-01-01

A new set of two-fluid equations which are valid from collisional to weakly collisional limits are derived. Starting from gyrokinetic equations in flux coordinates with no zeroth order drifts, a set of moment equations describing plasma transport along the field lines of a space and time dependent magnetic field are derived. No restriction on the anisotropy of the ion distribution function is imposed. In the highly collisional limit, these equations reduce to those of Braginskii while in the weakly collisional limit, they are similar to the double adiabatic or Chew, Goldberger, and Low (CGL) equations. The new transport equations are used to study the effects of collisionality, magnetic field structure, and plasma anisotropy on plasma parallel transport. Numerical examples comparing these equations with conventional transport equations show that the conventional equations may contain large errors near the sound speed (M approx. = 1). It is also found that plasma anisotropy, which is not included in the conventional equations, is a critical parameter in determining plasma transport in varying magnetic field. The new transport equations are also used to study axial confinement in multiple mirror devices from the strongly to weakly collisional regime. A new ion conduction model was worked out to extend the regime of validity of the transport equations to the low density multiple mirror regime

16 CFR 500.7 - Net quantity of contents, method of expression.

Science.gov (United States)

2010-01-01

... expression. The net quantity of contents shall be expressed in terms of weight or mass, measure, numerical... consumers. The net quantity of contents statement shall be in terms of fluid measure if the commodity is liquid, or in terms of weight or mass if the commodity is solid, semi-solid, or viscous, or a mixture of...

Convective and diffusive effects on particle transport in asymmetric periodic capillaries.

Directory of Open Access Journals (Sweden)

Nazmul Islam

Full Text Available We present here results of a theoretical investigation of particle transport in longitudinally asymmetric but axially symmetric capillaries, allowing for the influence of both diffusion and convection. In this study we have focused attention primarily on characterizing the influence of tube geometry and applied hydraulic pressure on the magnitude, direction and rate of transport of particles in axi-symmetric, saw-tooth shaped tubes. Three initial value problems are considered. The first involves the evolution of a fixed number of particles initially confined to a central wave-section. The second involves the evolution of the same initial state but including an ongoing production of particles in the central wave-section. The third involves the evolution of particles a fully laden tube. Based on a physical model of convective-diffusive transport, assuming an underlying oscillatory fluid velocity field that is unaffected by the presence of the particles, we find that transport rates and even net transport directions depend critically on the design specifics, such as tube geometry, flow rate, initial particle configuration and whether or not particles are continuously introduced. The second transient scenario is qualitatively independent of the details of how particles are generated. In the third scenario there is no net transport. As the study is fundamental in nature, our findings could engender greater understanding of practical systems.

Net radiative forcing and air quality responses to regional CO emission reductions

Directory of Open Access Journals (Sweden)

M. M. Fry

2013-05-01

Full Text Available Carbon monoxide (CO emissions influence global and regional air quality and global climate change by affecting atmospheric oxidants and secondary species. We simulate the influence of halving anthropogenic CO emissions globally and individually from 10 regions on surface and tropospheric ozone, methane, and aerosol concentrations using a global chemical transport model (MOZART-4 for the year 2005. Net radiative forcing (RF is then estimated using the GFDL (Geophysical Fluid Dynamics Laboratory standalone radiative transfer model. We estimate that halving global CO emissions decreases global annual average concentrations of surface ozone by 0.45 ppbv, tropospheric methane by 73 ppbv, and global annual net RF by 36.1 mW m−2, nearly equal to the sum of changes from the 10 regional reductions. Global annual net RF per unit change in emissions and the 100 yr global warming potential (GWP100 are estimated as −0.124 mW m−2 (Tg CO−1 and 1.34, respectively, for the global CO reduction, and ranging from −0.115 to −0.131 mW m−2 (Tg CO−1 and 1.26 to 1.44 across 10 regions, with the greatest sensitivities for regions in the tropics. The net RF distributions show widespread cooling corresponding to the O3 and CH4 decreases, and localized positive and negative net RFs due to changes in aerosols. The strongest annual net RF impacts occur within the tropics (28° S–28° N followed by the northern midlatitudes (28° N–60° N, independent of reduction region, while the greatest changes in surface CO and ozone concentrations occur within the reduction region. Some regional reductions strongly influence the air quality in other regions, such as East Asia, which has an impact on US surface ozone that is 93% of that from North America. Changes in the transport of CO and downwind ozone production clearly exceed the direct export of ozone from each reduction region. The small variation in CO GWPs among world regions suggests that future international

Application of a two fluid theoretical plasma transport model on current tokamak reactor designs

International Nuclear Information System (INIS)

Ibrahim, E.; Fowler, T.K.

1987-06-01

In this work, the new theoretical transport models to TIBER II design calculations are described and the results are compared with recent experimental data in large tokamaks (TFTR, JET). Tang's method is extended to a two-fluid model treating ions and electrons separately. This allows for different ion and electron temperatures, as in recent low-density experiments in TFTR, and in the TIBER II design itself. The discussion is divided into two parts: (1) Development of the theoretical transport model and (2) calibration against experiments and application to TIBER II

Numerical and experimental analysis of the hydroelastic behavior of purse seine nets

OpenAIRE

Riziotis, V. A.; Katsaounis, G. M.; Papadakis, G.; Voutsinas, S. G.; Bergeles, G.; Tzabiras, G. D.

2013-01-01

The paper presents a general three dimensional hydro-elastic tool for the analysis of different types of fishing nets and aquaculture facilities. Flexible net strands are modeled by non-linear truss elements having two nodes. Hydrodynamic loads due to relative motion of the net with the surrounding fluid are computed using the Morison equation. The coupled hydrodynamic-elastodynamic equations are solved using finite element (FE) approximations. Furthermore, experimental data are presented for...

Effect of drink carbohydrate content on postexercise gastric emptying, rehydration, and the calculation of net fluid balance.

Science.gov (United States)

Clayton, David J; Evans, Gethin H; James, Lewis J

2014-02-01

The purpose of this study was to examine the gastric emptying and rehydration effects of hypotonic and hypertonic glucose-electrolyte drinks after exercise-induced dehydration. Eight healthy males lost ~1.8% body mass by intermittent cycling and rehydrated (150% of body mass loss) with a hypotonic 2% (2% trial) or a hypertonic 10% (10% trial) glucose-electrolyte drink over 60 min. Blood and urine samples were taken at preexercise, postexercise, and 60, 120, 180, and 240 min postexercise. Gastric and test drink volume were determined 15, 30, 45, 60, 90, and 120 min postexercise. At the end of the gastric sampling period 0.3% (2% trial) and 42.1% (10% trial; p rehydration drink might be mediated by a slower rate of gastric emptying, but the slow gastric emptying of such solutions makes rehydration efficiency difficult to determine in the hours immediately after drinking, compromising the calculation of net fluid balance.

Effects of overlapping electric double layer on mass transport of a macro-solute across porous wall of a micro/nanochannel for power law fluid.

Science.gov (United States)

Bhattacharjee, Saikat; Mondal, Mrinmoy; De, Sirshendu

2017-05-01

Effects of overlapping electric double layer and high wall potential on transport of a macrosolute for flow of a power law fluid through a microchannel with porous walls are studied in this work. The electric potential distribution is obtained by coupling the Poisson's equation without considering the Debye-Huckel approximation. The numerical solution shows that the center line potential can be 16% of wall potential at pH 8.5, at wall potential -73 mV and scaled Debye length 0.5. Transport phenomena involving mass transport of a neutral macrosolute is formulated by species advective equation. An analytical solution of Sherwood number is obtained for power law fluid. Effects of fluid rheology are studied in detail. Average Sherwood number is more for a pseudoplastic fluid compared to dilatant upto the ratio of Poiseuille to electroosmotic velocity of 5. Beyond that, the Sherwood number is independent of fluid rheology. Effects of fluid rheology and solute size on permeation flux and concentration of neutral solute are also quantified. More solute permeation occurs as the fluid changes from pseudoplastic to dilatant. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of biological flow and transport in complex geometries using embedded boundary/volume-of-fluid methods

International Nuclear Information System (INIS)

Trebotich, David

2007-01-01

We have developed a simulation capability to model multiscale flow and transport in complex biological systems based on algorithms and software infrastructure developed under the SciDAC APDEC CET. The foundation of this work is a new hybrid fluid-particle method for modeling polymer fluids in irregular microscale geometries that enables long-time simulation of validation experiments. Both continuum viscoelastic and discrete particle representations have been used to model the constitutive behavior of polymer fluids. Complex flow environment geometries are represented on Cartesian grids using an implicit function. Direct simulation of flow in the irregular geometry is then possible using embedded boundary/volume-of-fluid methods without loss of geometric detail. This capability has been used to simulate biological flows in a variety of application geometries including biomedical microdevices, anatomical structures and porous media

Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

DEFF Research Database (Denmark)

Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

2016-01-01

of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output......This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC....... The net power outputs of all the feasible working fluids were ranked including their uncertainties. The method could propagate and quantify the input property uncertainty of the fluidproperty parameters to the ORC model, giving an additional dimension to the fluid selection process. In the given analysis...

Transport efficiency in transdermal drug delivery: What is the role of fluid microstructure?

Science.gov (United States)

Liuzzi, Roberta; Carciati, Antonio; Guido, Stefano; Caserta, Sergio

2016-03-01

Interaction of microstructured fluids with skin is ubiquitous in everyday life, from the use of cosmetics, lotions, and drugs, to personal care with detergents or soaps. The formulation of microstructured fluids is crucial for the control of the transdermal transport. In biomedical applications transdermal delivery is an efficient approach, alternative to traditional routes like oral and parenteral administration, for local release of drugs. Poor skin permeability, mainly due to its outer layer, which acts as the first barrier against the entry of external compounds, greatly limits the applicability of transdermal delivery. In this review, we focus on recent studies on the improvement of skin transport efficiency by using microemulsions (ME). Quantitative techniques, which are able to investigate both skin morphology and penetration processes, are also reviewed. ME are increasingly used as transdermal systems due to their low preparation cost, stability and high bioavailability. ME may act as penetration enhancers for many active principles, but ME microstructure should be chosen appropriately considering several factors such as ratio and type of ingredients and physic-chemical properties of the active components. ME microstructure is strongly affected by the flow conditions applied during processing, or during spreading and rubbing onto skin. Although the role played by ME microstructure has been generally recognized, the skin transport mechanisms associated with different ME microstructures are still to be elucidated and further investigations are required to fully exploit the potential of ME in transdermal delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluid Survival Tool: A Model Checker for Hybrid Petri Nets

NARCIS (Netherlands)

Postema, Björn Frits; Remke, Anne Katharina Ingrid; Haverkort, Boudewijn R.H.M.; Ghasemieh, Hamed

2014-01-01

Recently, algorithms for model checking Stochastic Time Logic (STL) on Hybrid Petri nets with a single general one-shot transition (HPNG) have been introduced. This paper presents a tool for model checking HPNG models against STL formulas. A graphical user interface (GUI) not only helps to

Interactive FORTRAN IV computer programs for the thermodynamic and transport properties of selected cryogens (fluids pack)

Science.gov (United States)

Mccarty, R. D.

1980-01-01

The thermodynamic and transport properties of selected cryogens had programmed into a series of computer routines. Input variables are any two of P, rho or T in the single phase regions and either P or T for the saturated liquid or vapor state. The output is pressure, density, temperature, entropy, enthalpy for all of the fluids and in most cases specific heat capacity and speed of sound. Viscosity and thermal conductivity are also given for most of the fluids. The programs are designed for access by remote terminal; however, they have been written in a modular form to allow the user to select either specific fluids or specific properties for particular needs. The program includes properties for hydrogen, helium, neon, nitrogen, oxygen, argon, and methane. The programs include properties for gaseous and liquid states usually from the triple point to some upper limit of pressure and temperature which varies from fluid to fluid.

The role of carbon dioxide in the transport and fractionation of metals by geological fluids

Science.gov (United States)

Kokh, Maria A.; Akinfiev, Nikolay N.; Pokrovski, Gleb S.; Salvi, Stefano; Guillaume, Damien

2017-01-01

Although carbon dioxide is one of the major components of crustal fluids responsible for ore deposit formation, its effect on transport and precipitation of metals remains unknown, due to a lack of direct experimental data and physical-chemical models for CO2-rich fluids. To fill this gap, we combined laboratory experiments and thermodynamic modeling to systematically quantify the role played by CO2 for the solubility of economically important metals such as Fe, Cu, Zn, Au, Mo, Pt, Sn under hydrothermal conditions. Solubility measurements of common ore minerals of these metals (FeS2, CuFeS2, ZnS, Au, MoS2, PtS, SnO2) were performed, using a flexible-cell reactor equipped with a rapid sampling device, in a single-phase fluid (CO2-H2O-KCl) at 350-450 °C and 600-750 bar, buffered with iron sulfide and oxide and alkali-aluminosilicate mineral assemblages. In addition, another type of experiments was conducted to measure gold solubility in more sulfur-rich supercritical CO2-H2O-S-NaOH fluids at 450 °C and 700 bar using a batch reactor that allows fluid quenching. Our results show that the solubilities of Si, Au, Mo, Pt and Cu either decrease (within 1 log unit) with CO2 contents in the fluid increasing from 0 to 50 wt%. These data were interpreted using a simple model that does not require any new adjustable parameters, and is based on the dielectric constant of the H2O-CO2 solvent and on the Born solvation parameter for the dominant metal-bearing species in an aqueous fluid. Our predictions using this model suggest that in a supercritical CO2-H2O-S-salt fluid typical of metamorphic Au deposits, in equilibrium with pyrite and chalcopyrite, the Cu/Fe ratio decreases by up to 2 orders of magnitude with an increase of CO2 content from 0 to 70 wt%. This effect is due to the decrease of the fluid dielectric constant in the presence of CO2, which favors the stability of neutral species (FeCl20) compared to charged ones (CuCl2-). Our results explain the Fe enrichment and Cu

K+ channel openers restore verapamil-inhibited lung fluid resolution and transepithelial ion transport

Directory of Open Access Journals (Sweden)

Su Xue-Feng

2010-05-01

Full Text Available Abstract Background Lung epithelial Na+ channels (ENaC are regulated by cell Ca2+ signal, which may contribute to calcium antagonist-induced noncardiogenic lung edema. Although K+ channel modulators regulate ENaC activity in normal lungs, the therapeutical relevance and the underlying mechanisms have not been completely explored. We hypothesized that K+ channel openers may restore calcium channel blocker-inhibited alveolar fluid clearance (AFC by up-regulating both apical and basolateral ion transport. Methods Verapamil-induced depression of heterologously expressed human αβγ ENaC in Xenopus oocytes, apical and basolateral ion transport in monolayers of human lung epithelial cells (H441, and in vivo alveolar fluid clearance were measured, respectively, using the two-electrode voltage clamp, Ussing chamber, and BSA protein assays. Ca2+ signal in H441 cells was analyzed using Fluo 4AM. Results The rate of in vivo AFC was reduced significantly (40.6 ± 6.3% of control, P Ca3.1 (1-EBIO and KATP (minoxidil channel openers significantly recovered AFC. In addition to short-circuit current (Isc in intact H441 monolayers, both apical and basolateral Isc levels were reduced by verapamil in permeabilized monolayers. Moreover, verapamil significantly altered Ca2+ signal evoked by ionomycin in H441 cells. Depletion of cytosolic Ca2+ in αβγ ENaC-expressing oocytes completely abolished verapamil-induced inhibition. Intriguingly, KV (pyrithione-Na, K Ca3.1 (1-EBIO, and KATP (minoxidil channel openers almost completely restored the verapamil-induced decrease in Isc levels by diversely up-regulating apical and basolateral Na+ and K+ transport pathways. Conclusions Our observations demonstrate that K+ channel openers are capable of rescuing reduced vectorial Na+ transport across lung epithelial cells with impaired Ca2+ signal.

Effect of wall compliance on peristaltic transport of a Newtonian fluid in an asymmetric channel

Directory of Open Access Journals (Sweden)

Mohamed H. Haroun

2006-01-01

Full Text Available Peristaltic transport of an incompressible viscous fluid in an asymmetric compliant channel is studied. The channel asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitudes and phases. The fluid-solid interaction problem is investigated by considering equations of motion of both the fluid and the deformable boundaries. The driving mechanism of the muscle is represented by assuming the channel walls to be compliant. The phenomenon of the “mean flow reversal” is discussed. The effect of wave amplitude ratio, width of the channel, phase difference, wall elastance, wall tension, and wall damping on mean-velocity and reversal flow has been investigated. The results reveal that the reversal flow occurs near the boundaries which is not possible in the elastic symmetric channel case.

Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

DEFF Research Database (Denmark)

Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

2016-01-01

This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...... modeloutput, and provides the 95%-confidence interval of the net power output with respect to the fluid property uncertainties. The methodology has been applied to a molecular design problem for an ORCusing a low-temperature heat source and consisted of the following four parts: 1) formulation...... of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output...

A fully resolved fluid-structure-muscle-activation model for esophageal transport

Science.gov (United States)

Kou, Wenjun; Bhalla, Amneet P. S.; Griffith, Boyce E.; Johnson, Mark; Patankar, Neelesh A.

2013-11-01

Esophageal transport is a mechanical and physiological process that transfers the ingested food bolus from the pharynx to the stomach through a multi-layered esophageal tube. The process involves interactions between the bolus, esophageal wall composed of mucosal, circular muscle (CM) and longitudinal muscle (LM) layers, and neurally coordinated muscle activation including CM contraction and LM shortening. In this work, we present a 3D fully-resolved model of esophageal transport based on the immersed boundary method. The model describes the bolus as a Newtonian fluid, the esophageal wall as a multi-layered elastic tube represented by springs and beams, and the muscle activation as a traveling wave of sequential actuation/relaxation of muscle fibers, represented by springs with dynamic rest lengths. Results on intraluminal pressure profile and bolus shape will be shown, which are qualitatively consistent with experimental observations. Effects of activating CM contraction only, LM shortening only or both, for the bolus transport, are studied. A comparison among them can help to identify the role of each type of muscle activation. The support of grant R01 DK56033 and R01 DK079902 from NIH is gratefully acknowledged.

Multiphysical modelling of fluid transport through osteo-articular media

Directory of Open Access Journals (Sweden)

Thibault Lemaire

2010-03-01

Full Text Available In this study, a multiphysical description of fluid transport through osteo-articular porous media is presented. Adapted from the model of Moyne and Murad, which is intended to describe clayey materials behaviour, this multiscale modelling allows for the derivation of the macroscopic response of the tissue from microscopical information. First the model is described. At the pore scale, electrohydrodynamics equations governing the electrolyte movement are coupled with local electrostatics (Gauss-Poisson equation, and ionic transport equations. Using a change of variables and an asymptotic expansion method, the macroscopic description is carried out. Results of this model are used to show the importance of couplings effects on the mechanotransduction of compact bone remodelling.Neste estudo uma descrição multifísica do transporte de fluidos em meios porosos osteo articulares é apresentada. Adaptado a partir do modelo de Moyne e Murad proposto para descrever o comportamento de materiais argilosos a modelagem multiescala permite a derivação da resposta macroscópica do tecido a partir da informação microscópica. Na primeira parte o modelo é apresentado. Na escala do poro as equações da eletro-hidrodinâmica governantes do movimento dos eletrolitos são acopladas com a eletrostática local (equação de Gauss-Poisson e as equações de transporte iônico. Usando uma mudança de variáveis e o método de expansão assintótica a derivação macroscópica é conduzida. Resultados do modelo proposto são usados para salientar a importância dos efeitos de acoplamento sobre a transdução mecânica da remodelagem de ossos compactados.

Fluid mechanics in the perivascular space.

Science.gov (United States)

Wang, Peng; Olbricht, William L

2011-04-07

Perivascular space (PVS) within the brain is an important pathway for interstitial fluid (ISF) and solute transport. Fluid flowing in the PVS can affect these transport processes and has significant impacts on physiology. In this paper, we carry out a theoretical analysis to investigate the fluid mechanics in the PVS. With certain assumptions and approximations, we are able to find an analytical solution to the problem. We discuss the physical meanings of the solution and particularly examine the consequences of the induced fluid flow in the context of convection-enhanced delivery (CED). We conclude that peristaltic motions of the blood vessel walls can facilitate fluid and solute transport in the PVS. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fluid–fluid level in hepatic metastases: A characteristic sign of metastases of neuroendocrine origin

International Nuclear Information System (INIS)

Sommer, Wieland H.; Zech, Christoph J.; Bamberg, Fabian; Auernhammer, Christoph J.; Helck, Andreas; Paprottka, Philipp M.; Notohamiprodjo, Mike; Reiser, Maximilian F.; Herrmann, Karin A.

2012-01-01

Objectives: The aim of this study is to determine MRI characteristics which indicate liver metastases of neuroendocrine tumors (NET) rather than metastases of other origin (non-NET). Methods: Sixty-nine patients with histopathologically proven liver metastases from NET and 69 patients with known liver metastases of other origin underwent MRI of the liver using a 1.5 T MR-scanner. Two board certified radiologists assessed presence of fluid–fluid-levels, number and distribution pattern, signal intensity (SI) characteristics, lesion homogeneity, presence of central necrosis and intratumoral hemorrhage in T2w and T1w non-contrast imaging. A multivariate logistic regression analysis was performed to determine the independent association of image findings and occurrence of NET. Results: Fluid–fluid-levels were identified in 19/69 of patients with NET-metastases, and in none of the patients in the control group (p < 0.0001). Hyperintense SI in T1w imaging, markedly hyperintense SI in T2w imaging, a disseminated distribution pattern and intratumoral hemorrhage were indicative of NET metastases (p < 0.05). After statistical adjustment for all significant MRI findings, fluid–fluid-levels (OR: 17.6, 95% CI: 1.9–166.5), strongly hyperintense SI in T2w (OR: 4.7, 95% CI: 1.8–12.7) and a disseminated distribution pattern (OR: 2.9, 95% CI: 1.1–7.4) were independent predictors for NET metastases. Conclusions: The presence of fluid–fluid-levels is highly indicative of NET liver metastases and can be used as an independent predictor to distinguish them from metastases of other origin

Mapping the spatiotemporal evolution of solute transport in articular cartilage explants reveals how cartilage recovers fluid within the contact area during sliding.

Science.gov (United States)

Graham, Brian T; Moore, Axel C; Burris, David L; Price, Christopher

2018-04-11

The interstitial fluid within articular cartilage shields the matrix from mechanical stresses, reduces friction and wear, enables biochemical processes, and transports solutes into and out of the avascular extracellular matrix. The balanced competition between fluid exudation and recovery under load is thus critical to the mechanical and biological functions of the tissue. We recently discovered that sliding alone can induce rapid solute transport into buried cartilage contact areas via a phenomenon termed tribological rehydration. In this study, we use in situ confocal microscopy measurements to track the spatiotemporal propagation of a small neutral solute into the buried contact area to clarify the fluid mechanics underlying the tribological rehydration phenomenon. Sliding experiments were interrupted by periodic static loading to enable scanning of the entire contact area. Spatiotemporal patterns of solute transport combined with tribological data suggested pressure driven flow through the extracellular matrix from the contact periphery rather than into the surface via a fluid film. Interestingly, these testing interruptions also revealed dynamic, repeatable and history-independent fluid loss and recovery processes consistent with those observed in vivo. Unlike the migrating contact area, which preserves hydration by moving faster than interstitial fluid can flow, our results demonstrate that the stationary contact area can maintain and actively recover hydration through a dynamic competition between load-induced exudation and sliding-induced recovery. The results demonstrate that sliding contributes to the recovery of fluid and solutes by cartilage within the contact area while clarifying the means by which it occurs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transport tensors in perfectly aligned low-density fluids: Self-diffusion and thermal conductivity

International Nuclear Information System (INIS)

Singh, G. S.; Kumar, B.

2001-01-01

The modified Taxman equation for the kinetic theory of low-density fluids composed of rigid aspherical molecules possessing internal degrees of freedom is generalized to obtain the transport tensors in a fluid of aligned molecules. The theory takes care of the shape of the particles exactly but the solution has been obtained only for the case of perfectly aligned hard spheroids within the framework of the first Sonine polynomial approximation. The expressions for the thermal-conductivity components have been obtained for the first time whereas the self-diffusion components obtained here turn out to be exactly the same as those derived by Kumar and Masters [Mol. Phys. >81, 491 (1994)] through the solution of the Lorentz-Boltzmann equation. All our expressions yield correct results in the hard-sphere limit

Characterization of active ion transport across primary rabbit corneal epithelial cell layers (RCrECL) cultured at an air-interface.

Science.gov (United States)

Chang-Lin, Joan-En; Kim, Kwang-Jin; Lee, Vincent H L

2005-06-01

Previously, we reported the development of a primary culture model of tight rabbit corneal epithelial cell layers (RCrECL) characterizing bioelectric parameters, morphology, cytokeratin, and passive permeability. In the present study, we specifically evaluated the active ion transport processes of RCrECL cultured from either pigmented or albino rabbits. Primary cultured RCrECL were grown at an air-interface on Clear-Snapwells precoated with collagen/fibronectin/laminin and mounted in a modified Ussing-type chamber for the evaluation of their active ion transport processes under short-circuited conditions. Contribution of active Na(+) and Cl(-) transport to overall short-circuit current (I(sc)) was evaluated by removing Na(+) and Cl(-), respectively, from bathing fluids of RCrECL and measurements of net fluxes of Na(+) and Cl(-) using (22)Na and (36)Cl, respectively. Amiloride and benzamil were used to determine the role of apical Na(+)-channel activities to net Na(+) fluxes. N-phenylanthranilic acid (NPAA), ouabain, BaCl(2) and bumetanide were used to determine the role of basolateral Na,K-ATPase, apical Cl(-)-channel, and basolateral K(+)-channel and Na(+)(K(+))2Cl(-)-cotransporter activities, respectively, in active ion transport across RCrECL. I(sc) of RCrECL derived from pigmented rabbits was comprised of 64+/-2% and 44+/-5% for active Na(+) and Cl(-) transport, respectively, consistent with net Na(+) absorption and Cl(-) secretion of 0.062+/-0.006 and 0.046+/-0.008 muEq/cm(2)/hr estimated from radionuclide fluxes. Apical amiloride and benzamil inhibited I(sc) by up to approximately 50% with an IC(50) of 1 and 0.1 microm, respectively, consistent with participation of apical epithelial Na(+)-channels to net Na(+) absorption across RCrECL cultured from pigmented rabbits. Addition of ouabain to the basolateral, NPAA to the apical, BaCl(2) to the basolateral and bumetanide to basolateral fluid decreased I(sc) by 86+/-1.5%, 53+/-3%, 18+/-1.8% and 13+/-1.9% in RCr

Preliminary model of fluid and solute distribution and transport during hemorrhage.

Science.gov (United States)

Gyenge, C C; Bowen, B D; Reed, R K; Bert, J L

2003-01-01

The distribution and transport of fluid, ions, and other solutes (plasma proteins and glucose) are described in a mathematical model of unresuscitated hemorrhage. The model is based on balances of each material in both the circulation and its red blood cells, as well as in a whole-body tissue compartment along with its cells. Exchange between these four compartments occurs by a number of different mechanisms. The hemorrhage model has as its basis a validated model, due to Gyenge et al., of fluid and solute exchange in the whole body of a standard human. Hypothetical but physiologically based features such as glucose and small ion releases along with cell membrane changes are incorporated into the hemorrhage model to describe the system behavior, particularly during larger hemorrhages. Moderate (10%-30% blood volume loss) and large (> 30% blood loss) hemorrhage dynamics are simulated and compared with available data. The model predictions compare well with the available information for both types of hemorrhages and provide a reasonable description of the progression of a large hemorrhage from the compensatory phase through vascular collapse.

A 3D FINITE ELEMENT ANALYSIS OF INCOMPRESSIBLE FLUID FLOW AND CONTAMINANT TRANSPORT THROUGH A POROUS LANDFILL

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ADEGUN, I. K.

2014-08-01

Full Text Available The paper investigated the flow of incompressible fluid and contaminant transport through a Porous Landfill using a numerical technique. A threedimensional finite element analysis technique was adopted for the solution. The problem was based on the Darcy’s Law and the Advection-Dispersion equation. The solutions of the Darcy’s and Advection-Dispersion equations were generated using Finite Element Analysis Software known as COMSOL Multiphysics. This simulation tool tracked the contaminant transport in the Landfill for 360 days at 10 days interval. It first modeled steady-state fluid flow by employing the Darcy’s Law Application Mode and then followed up with a transient solute-transport simulation by employing the Solute-Transport Application Mode from the Earth Science Module of COMSOL. The solution results obtained from this model were found to be in close agreement with reallife data obtained at the 130- million ton Bukit Tagar Mega Sanitary Landfill site, Selangor near Kuala Lumpur, Malaysia. This showed that the model can effectively predict the trends in the distributions of pollutants from a Municipal Solid Waste Landfill into nearby land and water sources. The model is thus applicable to the issues of environmental protection and safety of groundwater.

Stochastic porous media modeling and high-resolution schemes for numerical simulation of subsurface immiscible fluid flow transport

Science.gov (United States)

Brantson, Eric Thompson; Ju, Binshan; Wu, Dan; Gyan, Patricia Semwaah

2018-04-01

This paper proposes stochastic petroleum porous media modeling for immiscible fluid flow simulation using Dykstra-Parson coefficient (V DP) and autocorrelation lengths to generate 2D stochastic permeability values which were also used to generate porosity fields through a linear interpolation technique based on Carman-Kozeny equation. The proposed method of permeability field generation in this study was compared to turning bands method (TBM) and uniform sampling randomization method (USRM). On the other hand, many studies have also reported that, upstream mobility weighting schemes, commonly used in conventional numerical reservoir simulators do not accurately capture immiscible displacement shocks and discontinuities through stochastically generated porous media. This can be attributed to high level of numerical smearing in first-order schemes, oftentimes misinterpreted as subsurface geological features. Therefore, this work employs high-resolution schemes of SUPERBEE flux limiter, weighted essentially non-oscillatory scheme (WENO), and monotone upstream-centered schemes for conservation laws (MUSCL) to accurately capture immiscible fluid flow transport in stochastic porous media. The high-order schemes results match well with Buckley Leverett (BL) analytical solution without any non-oscillatory solutions. The governing fluid flow equations were solved numerically using simultaneous solution (SS) technique, sequential solution (SEQ) technique and iterative implicit pressure and explicit saturation (IMPES) technique which produce acceptable numerical stability and convergence rate. A comparative and numerical examples study of flow transport through the proposed method, TBM and USRM permeability fields revealed detailed subsurface instabilities with their corresponding ultimate recovery factors. Also, the impact of autocorrelation lengths on immiscible fluid flow transport were analyzed and quantified. A finite number of lines used in the TBM resulted into visual

A Forward Reachability Algorithm for Bounded Timed-Arc Petri Nets

DEFF Research Database (Denmark)

David, Alexandre; Jacobsen, Lasse; Jacobsen, Morten

2012-01-01

Timed-arc Petri nets (TAPN) are a well-known time extension of thePetri net model and several translations to networks of timedautomata have been proposed for this model.We present a direct, DBM-basedalgorithm for forward reachability analysis of bounded TAPNs extended with transport arcs...

Electron Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence

Science.gov (United States)

Che, Haihong

2013-10-01

To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation associated with electron heating in Buneman instability. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions can be described by a set of electron fluid equations. These equations show that the energy dissipation and momentum transports in Buneman instability are locally quasi-static but globally non-static and irreversible. Turbulence drag dissipates both the bulk energy of electron streams and the associated magnetic energy. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons. The net loss of streaming energy is converted into electron heat and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation which relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drives local momentum transports, while phase mixing converts convective momentum into thermal momentum.These two local momentum transports sustain the Buneman waves and act as the micro-macro link in the anomalous heating process. This research is supported by the NASA Postdoctoral Program at NASA/GSFC administered by Oak Ridge Associated Universities through a contract with NASA.

High-Speed Transport of Fluid Drops and Solid Particles via Surface Acoustic Waves

Science.gov (United States)

Bar-Cohen, Yoseph; Bao, Xiaoqi; Sherrit, Stewart; Badescu, Mircea; Lih, Shyh-shiuh

2012-01-01

A compact sampling tool mechanism that can operate at various temperatures, and transport and sieve particle sizes of powdered cuttings and soil grains with no moving parts, has been created using traveling surface acoustic waves (SAWs) that are emitted by an inter-digital transducer (IDT). The generated waves are driven at about 10 MHz, and it causes powder to move towards the IDT at high speed with different speeds for different sizes of particles, which enables these particles to be sieved. This design is based on the use of SAWs and their propelling effect on powder particles and fluids along the path of the waves. Generally, SAWs are elastic waves propagating in a shallow layer of about one wavelength beneath the surface of a solid substrate. To generate SAWs, a piezoelectric plate is used that is made of LiNbO3 crystal cut along the x-axis with rotation of 127.8 along the y-axis. On this plate are printed pairs of fingerlike electrodes in the form of a grating that are activated by subjecting the gap between the electrodes to electric field. This configuration of a surface wave transmitter is called IDT. The IDT that was used consists of 20 pairs of fingers with 0.4-mm spacing, a total length of 12.5 mm. The surface wave is produced by the nature of piezoelectric material to contract or expand when subjected to an electric field. Driving the IDT to generate wave at high amplitudes provides an actuation mechanism where the surface particles move elliptically, pulling powder particles on the surface toward the wavesource and pushing liquids in the opposite direction. This behavior allows the innovation to separate large particles and fluids that are mixed. Fluids are removed at speed (7.5 to 15 cm/s), enabling this innovation of acting as a bladeless wiper for raindrops. For the windshield design, the electrodes could be made transparent so that they do not disturb the driver or pilot. Multiple IDTs can be synchronized to transport water or powder over larger

Gas powered fluid gun with recoil mitigation

Science.gov (United States)

Grubelich, Mark C; Yonas, Gerold

2013-11-12

A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

Subcellular localization of the antidepressant-sensitive norepinephrine transporter

Directory of Open Access Journals (Sweden)

Winder Danny G

2009-06-01

Full Text Available Abstract Background Reuptake of synaptic norepinephrine (NE via the antidepressant-sensitive NE transporter (NET supports efficient noradrenergic signaling and presynaptic NE homeostasis. Limited, and somewhat contradictory, information currently describes the axonal transport and localization of NET in neurons. Results We elucidate NET localization in brain and superior cervical ganglion (SCG neurons, aided by a new NET monoclonal antibody, subcellular immunoisolation techniques and quantitative immunofluorescence approaches. We present evidence that axonal NET extensively colocalizes with syntaxin 1A, and to a limited degree with SCAMP2 and synaptophysin. Intracellular NET in SCG axons and boutons also quantitatively segregates from the vesicular monoamine transporter 2 (VMAT2, findings corroborated by organelle isolation studies. At the surface of SCG boutons, NET resides in both lipid raft and non-lipid raft subdomains and colocalizes with syntaxin 1A. Conclusion Our findings support the hypothesis that SCG NET is segregated prior to transport from the cell body from proteins comprising large dense core vesicles. Once localized to presynaptic boutons, NET does not recycle via VMAT2-positive, small dense core vesicles. Finally, once NET reaches presynaptic plasma membranes, the transporter localizes to syntaxin 1A-rich plasma membrane domains, with a portion found in cholera toxin-demarcated lipid rafts. Our findings indicate that activity-dependent insertion of NET into the SCG plasma membrane derives from vesicles distinct from those that deliver NE. Moreover, NET is localized in presynaptic membranes in a manner that can take advantage of regulatory processes targeting lipid raft subdomains.

Poly-N-acetylglucosamine matrix polysaccharide impedes fluid convection and transport of the cationic surfactant cetylpyridinium chloride through bacterial biofilms.

Science.gov (United States)

Ganeshnarayan, Krishnaraj; Shah, Suhagi M; Libera, Matthew R; Santostefano, Anthony; Kaplan, Jeffrey B

2009-03-01

Biofilms are composed of bacterial cells encased in a self-synthesized, extracellular polymeric matrix. Poly-beta(1,6)-N-acetyl-d-glucosamine (PNAG) is a major biofilm matrix component in phylogenetically diverse bacteria. In this study we investigated the physical and chemical properties of the PNAG matrix in biofilms produced in vitro by the gram-negative porcine respiratory pathogen Actinobacillus pleuropneumoniae and the gram-positive device-associated pathogen Staphylococcus epidermidis. The effect of PNAG on bulk fluid flow was determined by measuring the rate of fluid convection through biofilms cultured in centrifugal filter devices. The rate of fluid convection was significantly higher in biofilms cultured in the presence of the PNAG-degrading enzyme dispersin B than in biofilms cultured without the enzyme, indicating that PNAG decreases bulk fluid flow. PNAG also blocked transport of the quaternary ammonium compound cetylpyridinium chloride (CPC) through the biofilms. Binding of CPC to biofilms further impeded fluid convection and blocked transport of the azo dye Allura red. Bioactive CPC was efficiently eluted from biofilms by treatment with 1 M sodium chloride. Taken together, these findings suggest that CPC reacts directly with the PNAG matrix and alters its physical and chemical properties. Our results indicate that PNAG plays an important role in controlling the physiological state of biofilms and may contribute to additional biofilm-associated processes such as biocide resistance.

Geometry-coupled reactive fluid transport at the fracture scale -Application to CO 2 geologic storage

KAUST Repository

Kim, Seunghee

2015-08-19

Water acidification follows CO2 injection and leads to reactive fluid transport through pores and rock fractures, with potential implications to reservoirs and wells in CO2 geologic storage and enhanced oil recovery. Kinetic rate laws for dissolution reactions in calcite and anorthite are combined with Navier-Stokes law and advection-diffusion transport to perform geometry-coupled numerical simulations in order to study the evolution of chemical reactions, species concentration and fracture morphology. Results are summarized as a function of two dimensionless parameters: the Damköhler number Da which is the ratio between advection and reaction times, and the transverse Peclet number Pe defined as the ratio between the time for diffusion across the fracture and the time for advection along the fracture. Reactant species are readily consumed near the inlet in a carbonate reservoir when the flow velocity is low (low transverse Peclet number and Da>10-1). At high flow velocities, diffusion fails to homogenize the concentration field across the fracture (high transverse Peclet number Pe>10-1). When the reaction rate is low as in anorthite reservoirs (Da<10-1) reactant species are more readily transported towards the outlet. At a given Peclet number, a lower Damköhler number causes the flow channel to experience a more uniform aperture enlargement along the length of the fracture. When the length-to-aperture ratio is sufficiently large, say l/d>30, the system response resembles the solution for 1-D reactive fluid transport. A decreased length-to-aperture ratio slows the diffusive transport of reactant species to the mineral fracture surface, and analyses of fracture networks must take into consideration both the length and slenderness of individual fractures in addition to Pe and Da numbers.

Geometry-coupled reactive fluid transport at the fracture scale -Application to CO 2 geologic storage

KAUST Repository

Kim, Seunghee; Santamarina, Carlos

2015-01-01

Water acidification follows CO2 injection and leads to reactive fluid transport through pores and rock fractures, with potential implications to reservoirs and wells in CO2 geologic storage and enhanced oil recovery. Kinetic rate laws for dissolution reactions in calcite and anorthite are combined with Navier-Stokes law and advection-diffusion transport to perform geometry-coupled numerical simulations in order to study the evolution of chemical reactions, species concentration and fracture morphology. Results are summarized as a function of two dimensionless parameters: the Damköhler number Da which is the ratio between advection and reaction times, and the transverse Peclet number Pe defined as the ratio between the time for diffusion across the fracture and the time for advection along the fracture. Reactant species are readily consumed near the inlet in a carbonate reservoir when the flow velocity is low (low transverse Peclet number and Da>10-1). At high flow velocities, diffusion fails to homogenize the concentration field across the fracture (high transverse Peclet number Pe>10-1). When the reaction rate is low as in anorthite reservoirs (Da<10-1) reactant species are more readily transported towards the outlet. At a given Peclet number, a lower Damköhler number causes the flow channel to experience a more uniform aperture enlargement along the length of the fracture. When the length-to-aperture ratio is sufficiently large, say l/d>30, the system response resembles the solution for 1-D reactive fluid transport. A decreased length-to-aperture ratio slows the diffusive transport of reactant species to the mineral fracture surface, and analyses of fracture networks must take into consideration both the length and slenderness of individual fractures in addition to Pe and Da numbers.

Transport of fluid and solutes in the body II. Model validation and implications.

Science.gov (United States)

Gyenge, C C; Bowen, B D; Reed, R K; Bert, J L

1999-09-01

A mathematical model of short-term whole body fluid, protein, and ion distribution and transport developed earlier [see companion paper: C. C. Gyenge, B. D. Bowen, R. K. Reed, and J. L. Bert. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1215-H1227, 1999] is validated using experimental data available in the literature. The model was tested against data measured for the following three types of experimental infusions: 1) hyperosmolar saline solutions with an osmolarity in the range of 2,000-2,400 mosmol/l, 2) saline solutions with an osmolarity of approximately 270 mosmol/l and composition comparable with Ringer solution, and 3) an isosmotic NaCl solution with an osmolarity of approximately 300 mosmol/l. Good agreement between the model predictions and the experimental data was obtained with respect to the trends and magnitudes of fluid shifts between the intra- and extracellular compartments, extracellular ion and protein contents, and hematocrit values. The model is also able to yield information about inaccessible or difficult-to-measure system variables such as intracellular ion contents, cellular volumes, and fluid fluxes across the vascular capillary membrane, data that can be used to help interpret the behavior of the system.

Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealized model applied to the Yangtze Estuary

NARCIS (Netherlands)

Alebregtse, N. C.|info:eu-repo/dai/nl/345704304; de Swart, H. E.|info:eu-repo/dai/nl/073449725

2016-01-01

Tidal propagation in, and division of net water transport over different channels in an estuarine network are analyzed using a newly developed idealized model. The water motion in this model is governed by the cross-sectionally averaged shallow water equations and is forced by tides at the seaward

Application of ADINA fluid element for transient response analysis of fluid-structure system

International Nuclear Information System (INIS)

Sakurai, Y.; Kodama, T.; Shiraishi, T.

1985-01-01

Pressure propagation and Fluid-Structure Interaction (FSI) in 3D space were simulated by general purpose finite element program ADINA using the displacement-based fluid element which presumes inviscid and compressible fluid with no net flow. Numerical transient solution was compared with the measured data of an FSI experiment and was found to fairly agree with the measured. In the next step, post analysis was conducted for a blowdown experiment performed with a 1/7 scaled reactor pressure vessel and a flexible core barrel and the code performance was found to be satisfactory. It is concluded that the transient response of the core internal structure of a PWR during the initial stage of LOCA can be analyzed by the displacement-based finite fluid element and the structural element. (orig.)

Dynamical properties and transport coefficients of one-dimensional Lennard-Jones fluids: A molecular dynamics study

Science.gov (United States)

Bazhenov, Alexiev M.; Heyes, David M.

1990-01-01

The thermodynamics, structure, and transport coefficients, as defined by the Green-Kubo integrals, of the one-dimensional Lennard-Jones fluid are evaluated for a wide range of state points by molecular dynamics computer simulation. These calculations are performed for the first time for thermal conductivity and the viscosity. We observe a transition from hard-rod behavior at low number density to harmonic-spring fluid behavior in the close-packed limit. The self-diffusion coefficient decays with increasing density to a finite limiting value. The thermal conductivity increases with density, tending to ∞ in the close-packed limit. The viscosity in contrast maximizes at intermediate density, tending to zero in the zero density and close-packed limits.

Gut transport characteristics in herbivorous and carnivorous serrasalmid fish from ion-poor Rio Negro water.

Science.gov (United States)

Pelster, Bernd; Wood, Chris M; Speers-Roesch, Ben; Driedzic, William R; Almeida-Val, Vera; Val, Adalberto

2015-02-01

Three closely related characids, Tambaqui (omnivore), black Piranha (carnivore), and Pacu (herbivore), all Serrasalmidae, inhabit the ion-poor, acidic Rio Negro. We compared O2-consumption and N excretion rates in vivo, and sodium, chloride, glucose, and ammonia transport characteristics of gut sac preparations in vitro. The Pacu had a significantly higher weight-specific oxygen consumption, and a lower N/Q ratio than the omnivorous Tambaqui, and a significantly lower urea-N excretion rate than the carnivorous black Piranha, suggesting N-limitation in the herbivorous Pacu. With a value of 2.62 ± 0.15, gut to fork length ratio in the Pacu was about 2.5 times higher than in the black Piranha, and 2.0 times higher than in the Tambaqui. Anterior intestinal activities of three enzymes involved in N-fixation for amino acid synthesis (glutamate dehydrogenase, glutamate-oxaloacetate transferase, and glutamate-pyruvate transferase) were generally greatest in the carnivore and lowest in the herbivore species. In all three species, sodium, chloride, glucose, and ammonia were taken up at high rates from the intestine, resulting in an isosmotic fluid flux. Comparing the area-specific fluid flux of the anterior, mid, and posterior gut sections, no difference was detected between the three sections of the Pacu, while in the Tambaqui, it was highest in the anterior section, and in the black Piranha highest in the middle section. Overall, the area-specific uptake rates for sodium, chloride, glucose, and ammonia of anterior, mid, and posterior sections were similar in all three species, indicating that there is no difference in the area-specific transport rates associated with trophic position. The net ammonia uptake flux from gut interior was not significantly different from the net ammonia efflux to the serosal fluid, so that the ammonia removed from the intestine by the mucosal epithelium was quantitatively transferred through the tissue to the serosal side in all three

Fluid and solute transport in a network of channels

International Nuclear Information System (INIS)

Moreno, L.; Neretnieks, I.

1991-09-01

A three-dimensional channel network model is presented. The fluid flow and solute transport are assumed to take place through a network of connected channels. The channels are generated assuming that the conductances are lognormally distributed. The flow is calculated resolving the pressure distribution and the sole transport is calculated by using a particle tracking technique. The model includes diffusion into the rock matrix and sorption within the matrix in addition to advection along the channel network. Different approaches are used to describe the channel volume and its relation to the conductivity. To quantify the diffusion into the rock matrix the size of the flow wetted surface (contact surface between the channel and the rock) is needed in addition to the diffusion properties and the sorption capacity of the rock. Two different geometries were simulated: regional parallel flow and convergent flow toward a tunnel. In the generation of the channel network, it is found that its connectivity is reduced when the standard deviation in conductances is increased. For large standard deviations, the water conducting channels are found to be few. Standard deviations for the distribution of the effluent channel flowrates were calculated. Comparisons were made with experimental data from drifts and tunnels as well as boreholes as a means to validate the model. (au) (31 refs.)

Verification of Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Jacobsen, Lasse; Jacobsen, Morten; Møller, Mikael Harkjær

2011-01-01

of interesting theoretical properties distinguishing them from other time extensions of Petri nets. We shall give an overview of the recent theory developed in the verification of TAPN extended with features like read/transport arcs, timed inhibitor arcs and age invariants. We will examine in detail...

Methods of increasing net work output of organic Rankine cycles for low-grade waste heat recovery with a detailed analysis using a zeotropic working fluid mixture and scroll expander

Science.gov (United States)

Woodland, Brandon Jay

An organic Rankine cycle (ORC) is a thermodynamic cycle that is well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C -- 300 °C. When the application is strictly to convert waste heat into work, thermal efficiency is not recommended as a key performance metric. In such an application, maximization of the net power output should be the objective rather than maximization of the thermal efficiency. Two alternative cycle configurations that can increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are 1) an ORC with two-phase flash expansion and 2) an ORC with a zeotropic working fluid mixture (ZRC). A design-stage ORC model is presented for consistent comparison of multiple ORC configurations. The finite capacity of the heat source and heat sink fluids is a key consideration in this model. Of all working fluids studied for the baseline ORC, R134a and R245fa yield the highest net power output from a given heat source. Results of the design-stage model indicate that the ORC with two-phase flash expansion offers the most improvement over the baseline ORC. However, the level of improvement that could be achieved in practice is highly uncertain due to the requirement of highly efficient two-phase expansion. The ZRC shows improvement over the baseline as long as the condenser fan power requirement is not negligible. At the highest estimated condenser fan power, the ZRC shows the most improvement, while the ORC with flash expansion is no longer beneficial. The ZRC was selected for detailed study because it does not require two-phase expansion. An experimental test rig was used to evaluate baseline ORC performance with R134a and with R245fa. The ZRC was tested on the same rig with a mixture of 62.5% R134a and 37.5% R245fa. The tested expander is a minimally-modified, of-the-shelf automotive scroll compressor. The high

WE-NET: Japanese hydrogen program

International Nuclear Information System (INIS)

Mitsugi, Chiba; Harumi, Arai; Kenzo, Fukuda

1998-01-01

The Agency of Industrial Science and Technology (AIST), in the Ministry of International Trade and Industry (MITI), started the New Sunshine Program in 1993 by unifying the Sunshine Program (R and D on new energy technology), the Moonlight Program (R and D on energy conservation technology), and the Research and Development Program for Environmental Technology. The objective of the new program is to develop innovative technologies to allow sustainable growth while solving energy and environmental issues. One of the new projects in this program is the ''International Clean Energy System Technology Utilizing Hydrogen (World Energy Network)'': WE-NET. The goal of WE-NET is to construct a worldwide energy network for effective supply, transportation and utilization of renewable energy using hydrogen. The WE-NET program extends over 28 years from 1993 to 2020. In Phase 1, we started core research in areas such as development of high efficiency technologies including hydrogen production using polymer electrolyte membrane water electrolysis, hydrogen combustion turbines, etc. (author)

Computational Fluid Dynamics

International Nuclear Information System (INIS)

Myeong, Hyeon Guk

1999-06-01

This book deals with computational fluid dynamics with basic and history of numerical fluid dynamics, introduction of finite volume method using one-dimensional heat conduction equation, solution of two-dimensional heat conduction equation, solution of Navier-Stokes equation, fluid with heat transport, turbulent flow and turbulent model, Navier-Stokes solution by generalized coordinate system such as coordinate conversion, conversion of basic equation, program and example of calculation, application of abnormal problem and high speed solution of numerical fluid dynamics.

Molecular dynamics studies of transport properties and equation of state of supercritical fluids

Science.gov (United States)

Nwobi, Obika C.

Many chemical propulsion systems operate with one or more of the reactants above the critical point in order to enhance their performance. Most of the computational fluid dynamics (CFD) methods used to predict these flows require accurate information on the transport properties and equation of state at these supercritical conditions. This work involves the determination of transport coefficients and equation of state of supercritical fluids by equilibrium molecular dynamics (MD) simulations on parallel computers using the Green-Kubo formulae and the virial equation of state, respectively. MD involves the solution of equations of motion of a system of molecules that interact with each other through an intermolecular potential. Provided that an accurate potential can be found for the system of interest, MD can be used regardless of the phase and thermodynamic conditions of the substances involved. The MD program uses the effective Lennard-Jones potential, with system sizes of 1000-1200 molecules and, simulations of 2,000,000 time-steps for computing transport coefficients and 200,000 time-steps for pressures. The computer code also uses linked cell lists for efficient sorting of molecules, periodic boundary conditions, and a modified velocity Verlet algorithm for particle displacement. Particle decomposition is used for distributing the molecules to different processors of a parallel computer. Simulations have been carried out on pure argon, nitrogen, oxygen and ethylene at various supercritical conditions, with self-diffusion coefficients, shear viscosity coefficients, thermal conductivity coefficients and pressures computed for most of the conditions. Results compare well with experimental and the National Institute of Standards and Technology (NIST) values. The results show that the number of molecules and the potential cut-off radius have no significant effect on the computed coefficients, while long-time integration is necessary for accurate determination of the

Alternative transport fuels: supply, consumption and conservation

International Nuclear Information System (INIS)

Trindade, S.C.

1990-01-01

Road-based passenger and freight transport almost exclusively uses petroleum/hydrocarbon fuels in the fluid form. These fuels will probably continue to be major transport fuels well into the 21st century. As such there is need to prolong their use which can be done through: (1) conservation of fuel by increasing efficiency of internal combustion engines, and (2) conversion of natural gas, coal and peat, and biomass into alternate fuels such as ethanol, methanol, CNG, LNG, LPG, low heat-content (producer) gas and vegetable oils. Research, development and demonstration (RD and D) priorities in supply, consumption and conservation of these alternate fuels are identified and ranked in the context of situation prevailing in Brazil. Author has assigned the highest priority for research in the impact of pricing, economic, fiscal and trade policies, capital allocation criteria and institutional and legislative framework. It has also been emphasised that an integrated or systems approach is mandatory to achieve net energy gains in transport sector. (M.G.B.). 33 refs., 11 tabs., 4 figs

Microscale fluid transport using optically controlled marangoni effect

Science.gov (United States)

Thundat, Thomas G [Knoxville, TN; Passian, Ali [Knoxville, TN; Farahi, Rubye H [Oak Ridge, TN

2011-05-10

Low energy light illumination and either a doped semiconductor surface or a surface-plasmon supporting surface are used in combination for manipulating a fluid on the surface in the absence of any applied electric fields or flow channels. Precise control of fluid flow is achieved by applying focused or tightly collimated low energy light to the surface-fluid interface. In the first embodiment, with an appropriate dopant level in the semiconductor substrate, optically excited charge carriers are made to move to the surface when illuminated. In a second embodiment, with a thin-film noble metal surface on a dispersive substrate, optically excited surface plasmons are created for fluid manipulation. This electrode-less optical control of the Marangoni effect provides re-configurable manipulations of fluid flow, thereby paving the way for reprogrammable microfluidic devices.

Petri nets and fault diagnosis in nuclear reactors

International Nuclear Information System (INIS)

Jalel, N.A.; Nicholson, H.

1990-11-01

The possibility of applying Petri nets (Pns) as a modelling tool to represent any fault or accident that might occur in the Loss Of Fluid Test (LOFT) reactor, small scale pressurised water reactor, is discussed and analysed. Pns are developed to assist the nuclear reactor operator in identifying any fault or alarm that might arise in the power station. (author)

Peristaltic transport of Bingham plastic fluid considering magnetic field, Soret and Dufour effects

Science.gov (United States)

Hayat, T.; Farooq, S.; Mustafa, M.; Ahmad, B.

Current attempt addresses the peristaltic transport of Bingham plastic fluid under the influence of magnetic force. Space dependent viscosity is considered. Novel Soret and Dufour effects are retained in the mathematical model. Problem formulation is presented through the conventional lubrication approach. Series solutions of the arising non-linear problem are developed via regular perturbation approach. Special attention is given to the role of embedded parameters on the axial velocity, temperature, concentration and pressure distributions. Furthermore the numerical solution of pressure rise per wavelength is obtained through numerical integration because its analytical solution seems impossible.

Interaction of antidepressants with the serotonin and norepinephrine transporters

DEFF Research Database (Denmark)

Sørensen, Lena; Andersen, Jacob; Thomsen, Mette

2012-01-01

The serotonin transporter (SERT) and the norepinephrine transporter (NET) are sodium-dependent neurotransmitter transporters responsible for reuptake of released serotonin and norepinephrine, respectively, into nerve terminals in the brain. A wide range of inhibitors of SERT and NET are used...

An Eulerian two-phase flow model for sediment transport under realistic surface waves

Science.gov (United States)

Hsu, T. J.; Kim, Y.; Cheng, Z.; Chauchat, J.

2017-12-01

Wave-driven sediment transport is of major importance in driving beach morphology. However, the complex mechanisms associated with unsteadiness, free-surface effects, and wave-breaking turbulence have not been fully understood. Particularly, most existing models for sediment transport adopt bottom boundary layer approximation that mimics the flow condition in oscillating water tunnel (U-tube). However, it is well-known that there are key differences in sediment transport when comparing to large wave flume datasets, although the number of wave flume experiments are relatively limited regardless of its importance. Thus, a numerical model which can resolve the entire water column from the bottom boundary layer to the free surface can be a powerful tool. This study reports an on-going effort to better understand and quantify sediment transport under shoaling and breaking surface waves through the creation of open-source numerical models in the OpenFOAM framework. An Eulerian two-phase flow model, SedFoam (Cheng et al., 2017, Coastal Eng.) is fully coupled with a volume-of-fluid solver, interFoam/waves2Foam (Jacobsen et al., 2011, Int. J. Num. Fluid). The fully coupled model, named SedWaveFoam, regards the air and water phases as two immiscible fluids with the interfaces evolution resolved, and the sediment particles as dispersed phase. We carried out model-data comparisons with the large wave flume sheet flow data for nonbreaking waves reported by Dohmen-Janssen and Hanes (2002, J. Geophysical Res.) and good agreements were obtained for sediment concentration and net transport rate. By further simulating a case without free-surface (mimic U-tube condition), the effects of free-surface, most notably the boundary layer streaming effect on total transport, can be quantified.

Nonlinear transport processes and fluid dynamics: Cylindrical Couette flow of Lennard-Jones fluids

International Nuclear Information System (INIS)

Khayat, R.E.; Eu, B.C.

1988-01-01

In this paper we report on calculations of flow profiles for cylindrical Couette flow of a Lennard-Jones fluid. The flow is subjected to a temperature gradient and thermoviscous effects are taken into consideration. We apply the generalized fluid dynamic equations which are provided by the modified moment method for the Boltzmann equation reported previously. The results of calculations are in good agreement with the Monte Carlo direct simulation method by K. Nanbu [Phys. Fluids 27, 2632 (1984)] for most of Knudsen numbers for which the simulation data are available

Magmatic Vapor Phase Transport of Copper in Reduced Porphyry Copper-Gold Deposits: Evidence From PIXE Microanalysis of Fluid Inclusions

Science.gov (United States)

Rowins, S. M.; Yeats, C. J.; Ryan, C. G.

2002-05-01

Nondestructive proton-induced X-ray emission (PIXE) studies of magmatic fluid inclusions in granite-related Sn-W deposits [1] reveal that copper transport out of reduced felsic magmas is favored by low-salinity vapor and not co-existing high-salinity liquid (halite-saturated brine). Copper transport by magmatic vapor also has been documented in oxidized porphyry Cu-Au deposits, but the magnitude of Cu partitioning into the vapor compared to the brine generally is less pronounced than in the reduced magmatic Sn-W systems [2]. Consideration of these microanalytical data leads to the hypothesis that Cu and, by inference, Au in the recently established "reduced porphyry copper-gold" (RPCG) subclass should partition preferentially into vapor and not high-salinity liquid exsolving directly from fluid-saturated magmas [3-4]. To test this hypothesis, PIXE microanalysis of primary fluid inclusions in quartz-sulfide (pyrite, pyrrhotite & chalcopyrite) veins from two RPCG deposits was undertaken using the CSIRO-GEMOC nuclear microprobe. PIXE microanalysis for the ~30 Ma San Anton deposit (Mexico) was done on halite-saturated aqueous brine (deposit (W. Australia) was done on halite-saturated "aqueous" inclusions, which contain a small (deposits of the new RPCG subclass demonstrate the greater potential of these systems, compared to the classically oxidized porphyry Cu-Au systems, to transport Cu and probably precious metals in a magmatic aqueous vapor phase. These PIXE data also support the possibility that Cu partitions preferentially into an immiscible CO2-rich magmatic fluid. References: [1] Heinrich, C.A. et al. (1992) Econ. Geol., 87, 1566-1583. [2] Heinrich, C.A. et al. (1999) Geology, 27, 755-758. [3] Rowins, S.M. (2000) Geology, 28, 491-494. [4] Rowins, S.M. (2000) The Gangue, GAC-MDD Newsletter, 67, 1-7 (www.gac.ca). [5] Rowins, S.M. et al. (1993) Geol. Soc. Australia Abs., 34, 68-70.

Fundamental approach to the analysis of radionuclide transport resulting from fluid flow through jointed media

International Nuclear Information System (INIS)

Erickson, K.L.

1981-02-01

A theoretical and experimental basis is being developed for analysis of radionuclide transport in jointed geologic media. Batch equilibration and rate experiments involving samples of Eleana argillite and Tertiary silicic tuffs in contact with solutions containing Cs, Sr or Pm indicated that most radionuclide sorption is associated with the surfaces of very small intergranular regions and that the rate of sorption is controlled by diffusion of the nuclides into such regions. Based on these experimental results, the continuity equations for radionuclides in the mobile and immobile phases were reduced to a model analogous to Rosen's equations for packed beds and were solved similarly to Rosen's solutions. Using the model and experimental data, limited radionuclide transport analyses were made which indicated that important parameters controlling transport include the intergranular porosity and nuclide penetration depth, fracture plate spacing and length, fluid velocity, and sorption distribution coefficient

Computational studies in tokamak equilibrium and transport

International Nuclear Information System (INIS)

Braams, B.J.

1986-01-01

This thesis is concerned with some problems arising in the magnetic confinement approach to controlled thermonuclear fusion. The work address the numerical modelling of equilibrium and transport properties of a confined plasma and the interpretation of experimental data. The thesis is divided in two parts. Part 1 is devoted to some aspects of the MHD equilibrium problem, both in the 'direct' formulation (given an equation for the plasma current, the corresponding equilibrium is to be determined) and in the 'inverse' formulation (the interpretation of measurements at the plasma edge). Part 2 is devoted to numerical studies of the edge plasma. The appropriate Navier-Stokes system of fluid equations is solved in a two-dimensional geometry. The main interest of this work is to develop an understanding of particle and energy transport in the scrape-off layer and onto material boundaries, and also to contribute to the conceptual design of the NET/INTOR tokamak reactor experiment. (Auth.)

Building waste management core indicators through Spatial Material Flow Analysis: net recovery and transport intensity indexes.

Science.gov (United States)

Font Vivanco, David; Puig Ventosa, Ignasi; Gabarrell Durany, Xavier

2012-12-01

In this paper, the material and spatial characterization of the flows within a municipal solid waste (MSW) management system are combined through a Network-Based Spatial Material Flow Analysis. Using this information, two core indicators are developed for the bio-waste fraction, the Net Recovery Index (NRI) and the Transport Intensity Index (TII), which are aimed at assessing progress towards policy-related sustainable MSW management strategies and objectives. The NRI approaches the capacity of a MSW management system for converting waste into resources through a systematic metabolic approach, whereas the TII addresses efficiency in terms of the transport requirements to manage a specific waste flow throughout the entire MSW management life cycle. Therefore, both indicators could be useful in assessing key MSW management policy strategies, such as the consecution of higher recycling levels (sustainability principle) or the minimization of transport by locating treatment facilities closer to generation sources (proximity principle). To apply this methodological approach, the bio-waste management system of the region of Catalonia (Spain) has been chosen as a case study. Results show the adequacy of both indicators for identifying those points within the system with higher capacity to compromise its environmental, economic and social performance and therefore establishing clear targets for policy prioritization. Moreover, this methodological approach permits scenario building, which could be useful in assessing the outcomes of hypothetical scenarios, thus proving its adequacy for strategic planning. Copyright © 2012 Elsevier Ltd. All rights reserved.

StateGEN/StateNET - A structured method to perform route comparisons

International Nuclear Information System (INIS)

Cashwell, J.W.; Erickson, C.M.

1989-01-01

StateGEN/StateNET is a modeling structure and routing algorithm designed expressly to address the needs of state and local governments to perform analyses of routing alternatives. StateGEN/StateNET is designed to permit the user to construct a network and assign attributes of interest to the network on a personal computer (PC). The completed network is then transferred via a modem to the TRANSNET system and the preferred route is determined based upon attribute weights assigned by the user. This modeling structure permits the state or local government to perform a routing analysis, such as that required by the US Department of Transportation (DOT) for Highway Route-Controlled Quantity shipments of radioactive materials, with a minimum of resources. StateGEN/StateNET provides a computerized version of the DOT guidelines or allows the user to structure their own network parameters. Sandia National Laboratories (SNL) is the Department of Energy (DOE) lead organization for transportation research and development. The DOE Office of Defense Programs has been the prime sponsor of development of models and associated databases used to analyze the impacts of the transportation of radioactive materials. The routing algorithms used in StateGEN/StateNET were based on the existing models on TRANSNET, a system which was developed to enable outside users to access analytical codes and associated data developed for the DOE

StateGEN/StateNET--A structured method to perform route comparisons

International Nuclear Information System (INIS)

Cashwell, J.W.; Erickson, C.M.

1989-01-01

StateGEN/StateNET is a modelling structure and routing algorithm designed expressly to address the needs of state and local governments to perform analyses of routing alternatives. StateGEN/StateNET is designed to permit the user to construct a network and assign attributes of interest to the network on a personal computer (PC). The completed network is then transferred via a modem to the TRANSNET system (Cashwell, 1989) and the preferred route is determined based upon attribute weights assigned by the user. This modelling structure permits the state or local to perform a routing analysis, such as that required by the US Department of Transportation (DOT) for Highway Route-Controlled Quantity shipments of radioactive materials, with a minimum of resources. StateGEN/StateNET provides a computerized version of the DOT guidelines (Cashwell, 1989) or allows the user to structure their own network parameters. Sandia national Laboratories (SNL) is the Department of Energy's (DOE) lead organization for transportation research and development. The DOE Office of Defense Programs has been the prime sponsor of development of models and associated databases used to analyze the impacts of the transportation of radioactive materials. The routing algorithms used in StateGEN/StateNET were based on the existing models on TRANSNET, a system which was developed to enable outside users to access analytical codes and associated data developed for the DOE. 2 refs

Longshore sediment transport along the Indian coast

Digital Repository Service at National Institute of Oceanography (India)

Chandramohan, P.; Nayak, B.U.

Coast. Maharashtra Coast and the part between Pondicherry and Point Calimere in Tamilnadu, show negligible order of annual net transport. Annual net transport along the east coast is in north and along the west coast in south but for South Gujarat Coast....

Receptor-mediated mechanism for the transport of prolactin from blood to cerebrospinal fluid

International Nuclear Information System (INIS)

Walsh, R.J.; Slaby, F.J.; Posner, B.I.

1987-01-01

Prolactin (PRL) interacts with areas of the central nervous system which reside behind the blood-brain barrier. While vascular PRL does not cross this barrier, it is readily accessible to the cerebrospinal fluid (CSF) from which it may gain access to the PRL-responsive areas of the brain. Studies were undertaken to characterize the mechanism responsible for the translocation of PRL from blood to CSF. Rats were given external jugular vein injections of [ 125 -I]iodo-PRL in the presence or absence of an excess of unlabeled ovine PRL (oPRL), human GH, bovine GH, or porcine insulin. CSF and choroid plexus were removed 60 min later. CSF samples were electrophoresed on sodium dodecyl sulfate-polyacrylamide slab gels and resultant autoradiographs were analyzed with quantitative microdensitometry. The data revealed that unlabeled lactogenic hormones, viz. oPRL and human GH, caused a statistically significant inhibition of [ 125 I]iodo-PRL transport from blood to CSF. In contrast, nonlactogenic hormones, viz bovine GH and insulin, had no effect on [ 125 I]iodo-PRL transport into the CSF. An identical pattern of competition was observed in the binding of hormone to the choroid plexus. Furthermore, vascular injections of [ 125 I]iodo-PRL administered with a range of concentrations of unlabeled oPRL revealed a dose-response inhibition in the transport of [ 125 I]iodo-PRL from blood to CSF. The study demonstrates that PRL enters the CSF by a specific, PRL receptor-mediated transport mechanism. The data is consistent with the hypothesis that the transport mechanism resides at the choroid plexus. The existence of this transport mechanism reflects the importance of the cerebroventricular system in PRL-brain interactions

Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

International Nuclear Information System (INIS)

Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G.

2012-01-01

Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

NET-2 Network Analysis Program

International Nuclear Information System (INIS)

Malmberg, A.F.

1974-01-01

The NET-2 Network Analysis Program is a general purpose digital computer program which solves the nonlinear time domain response and the linearized small signal frequency domain response of an arbitrary network of interconnected components. NET-2 is capable of handling a variety of components and has been applied to problems in several engineering fields, including electronic circuit design and analysis, missile flight simulation, control systems, heat flow, fluid flow, mechanical systems, structural dynamics, digital logic, communications network design, solid state device physics, fluidic systems, and nuclear vulnerability due to blast, thermal, gamma radiation, neutron damage, and EMP effects. Network components may be selected from a repertoire of built-in models or they may be constructed by the user through appropriate combinations of mathematical, empirical, and topological functions. Higher-level components may be defined by subnetworks composed of any combination of user-defined components and built-in models. The program provides a modeling capability to represent and intermix system components on many levels, e.g., from hole and electron spatial charge distributions in solid state devices through discrete and integrated electronic components to functional system blocks. NET-2 is capable of simultaneous computation in both the time and frequency domain, and has statistical and optimization capability. Network topology may be controlled as a function of the network solution. (U.S.)

Self-consistent computation of transport barrier formation by fluid drift turbulence in tokamak geometry

International Nuclear Information System (INIS)

Scott, B.; Jenko, F.; Peeters, A.G.; Teo, A.C.Y.

1999-01-01

(1) Computations of turbulence from the electromagnetic gyro fluid model are performed in a flux surface geometry representing the actual MHD equilibrium of the ASDEX Upgrade edge flux surfaces. The transition to ideal ballooning seen in simple geometries as the plasma beta rises is suppressed, leaving the transport at quantitatively realistic levels. Computations for core parameters at half-radius geometry show significant contribution due to the finite beta electron dynamics, possibly removing the standard ITG threshold. (2) Strong inward vorticity transport in edge turbulence, resulting from ion diamagnetic flows, may lead to a build up of mean ExB vorticity fast enough to cause an H-mode transition. (3) Friction of mean ion flows against neutrals involves both toroidal and poloidal flow components, leading to a finite radial current due to a given ExB profile even with zero poloidal rotation. (author)

Building waste management core indicators through Spatial Material Flow Analysis: Net recovery and transport intensity indexes

International Nuclear Information System (INIS)

Font Vivanco, David; Puig Ventosa, Ignasi; Gabarrell Durany, Xavier

2012-01-01

Highlights: ► Sustainability and proximity principles have a key role in waste management. ► Core indicators are needed in order to quantify and evaluate them. ► A systematic, step-by-step approach is developed in this study for their development. ► Transport may play a significant role in terms of environmental and economic costs. ► Policy action is required in order to advance in the consecution of these principles. - Abstract: In this paper, the material and spatial characterization of the flows within a municipal solid waste (MSW) management system are combined through a Network-Based Spatial Material Flow Analysis. Using this information, two core indicators are developed for the bio-waste fraction, the Net Recovery Index (NRI) and the Transport Intensity Index (TII), which are aimed at assessing progress towards policy-related sustainable MSW management strategies and objectives. The NRI approaches the capacity of a MSW management system for converting waste into resources through a systematic metabolic approach, whereas the TII addresses efficiency in terms of the transport requirements to manage a specific waste flow throughout the entire MSW management life cycle. Therefore, both indicators could be useful in assessing key MSW management policy strategies, such as the consecution of higher recycling levels (sustainability principle) or the minimization of transport by locating treatment facilities closer to generation sources (proximity principle). To apply this methodological approach, the bio-waste management system of the region of Catalonia (Spain) has been chosen as a case study. Results show the adequacy of both indicators for identifying those points within the system with higher capacity to compromise its environmental, economic and social performance and therefore establishing clear targets for policy prioritization. Moreover, this methodological approach permits scenario building, which could be useful in assessing the outcomes of

Fluid simulations of ∇Te-driven turbulence and transport in boundary plasmas

International Nuclear Information System (INIS)

Xu, X.Q.

1992-01-01

It is clear that the edge plasma plays a crucial role in global tokamak confinement. This paper is a report on simulations of a new drift wave type instability driven by the electron temperature gradient in tokamak scrapeoff-layers (SOL). A 2d fluid code has been developed in order to explore the anomalous transport in the boundary plasmas. The simulation consists of a set of fluid equations for the vorticity ∇ perpendicular 2 φ, the electron density n c and the temperature T c in a shearless plasma slab confined by a uniform, straight magnetic field B z with two divertor (or limiter) plates intercepting the magnetic field. The model has two regions separated by a magnetic separatrix: in the edge region inside the separatrix, the model is periodic along the magnetic field while in the SOL region outside the separatrix, the magnetic field is taken to be of finite length with model boundary conditions at diverter plates. The simulation results show that the observed linear instability agrees well with theory, and that a saturated state of turbulence is reached. In saturated turbulence, clear evidence of the expected long-wavelength mode penetration into the edge is seen, an inverse cascade of wave energy is observed. The simulation results also show that amplitudes of potential and the electron temperature fluctuations are somewhat above and the heat flux are somewhat below those of the simplest mixing-length estimates, and furthermore the large-scale radial structures of fluctuation quantities indicate that the cross-field transport is not diffusive. After saturation, the electron density and temperature profiles are flattened. A self-consistent simulation to determine the microturbulent SOL electron temperature profile has been done, the results of which reasonably agree with the experimental measurements

Thermodynamic and transport properties of nitrogen fluid: Molecular theory and computer simulations

Science.gov (United States)

Eskandari Nasrabad, A.; Laghaei, R.

2018-04-01

Computer simulations and various theories are applied to compute the thermodynamic and transport properties of nitrogen fluid. To model the nitrogen interaction, an existing potential in the literature is modified to obtain a close agreement between the simulation results and experimental data for the orthobaric densities. We use the Generic van der Waals theory to calculate the mean free volume and apply the results within the modified Cohen-Turnbull relation to obtain the self-diffusion coefficient. Compared to experimental data, excellent results are obtained via computer simulations for the orthobaric densities, the vapor pressure, the equation of state, and the shear viscosity. We analyze the results of the theory and computer simulations for the various thermophysical properties.

Ion transporters for fluid reabsorption in the rooster (Gallus domesticus) epididymal region.

Science.gov (United States)

Bahr, J M; Dalponte, M; Janssen, S; Bunick, D; Nakai, M

2006-10-01

Testicular fluid is highly condensed during its passage through the epididymal region in the avian species. In the present study, major ion transporters that are responsible for condensation mainly by water resorption in the reproductive tract as identified in the mammalian epididymis were localized within the rooster (Gallus domesticus) epididymis by immunohistochemistry. The results show that the efferent ductule epithelium expressed sodium-potassium ATPase (Na(+),K(+)-ATPase), carbonic anhydrase II (CAII) and sodium hydrogen exchanger isoform 3 (NHE3) and that the connecting ductule and epididymal duct epithelia expressed Na(+),K(+)-ATPase and CAII. These data suggest that a model proposed for reabsorption in mammalian efferent ductules can be applied to avian efferent ductules.

Fluid and heat transport at the Torres del Paine laccolith (Patagonia/Chile)

International Nuclear Information System (INIS)

Putliz, B; Baumgartner, L.P; Oberhansli, R; Diamond, L; Altenberger, U

2001-01-01

The 12 Ma old Torres del Paine laccolith (TPL) is part of a chain of isolated Miocene plutons and subvolcanic rocks which intruded the foothills of the southern Andes of Chile and Argentina (Halpern, 1973; Michael, 1984). The 12x12 km big laccolith, an I-type granite, intruded mudstones, sandstones, carbonates and conglomerates of the Cretaceous Cerro Torre and Punta Barrosa formation (Wilson, 1991) creating a well defined, but small contact aureole of 200-400m width. The TPL contains abundant textural evidence of fluid exsolution and eutectic crystallisation. It hence represents a good example for the transport of large quantities of magmatic aqueous fluids to the uppermost level of the crust. The pluton is well exposed and its rugged topography allows the investigation of the roof, the lateral rims and the base of the intrusion. Field and textural observations, phase petrological constraints, oxygen isotope and fluid inclusion data are used to unravel mechanism and patterns of fluid and heat transport in the intrusion and the contact aureole. The Torres del Paine Intrusives form a calcalkaline suite, ranging from gabbros through diorites to leucogranites. The intrusive body has the general shape of a laccolith (Skarmeta and Castelli, 1997). Gabbroic and dioritic rocks are only exposed at the lower levels. Granites are clearly predominant - the main body of the laccolith is composed of a fine to medium grained biotite-orthoclase granite. The TPL is remarkable for its abundance of miarolitic cavities. Locally, at the margins of the pluton, a microgranitic phase is found with up to 15% of cavities. While some miaroles are isolated, others are interconnected, forming tube-like structures. Open miaroles contain euhedral crystals of quartz and feldspar. Other important phases are biotite, tourmaline, fayalite and late chlorite and carbonate. Individual crystals are typically between < 1cm up to a few cm in length. Some miaroles are completely filled with coarse quartz

Simulation of cerebrospinal fluid transport

Czech Academy of Sciences Publication Activity Database

Otáhal, Jakub; Štěpáník, Z.; Kaczmarská, A.; Maršík, František; Brož, Z.; Otáhal, S.

2007-01-01

Roč. 38, 11-12 (2007), s. 802-809 ISSN 0965-9978 Grant - others:GA UK(CZ) 112/2005; GA UK(CZ) 114/2005; GA ČR(CZ) GA106/03/0958 Program:GA Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z20760514 Keywords : cerebrospinal fluid * pulsation * mathematical modeling Subject RIV: BO - Biophysics Impact factor: 0.529, year: 2007

A longshore sediment transport estimation for the Indian coast

Digital Repository Service at National Institute of Oceanography (India)

Nayak, B.U.; Chandramohan, P.

in Tamilnadu, and the Maharashtra Coast experience negligible annual net transport. The direction of annual net transport along the east coast is towards north and along the west coast towards south except at south Gujarat Coast...

Initial Results From The Micro-pulse Lidar Network (MPL-Net)

Science.gov (United States)

Welton, E. J.; Campbell, J. R.; Berkoff, T. A.; Spinhirne, J. D.; Ginoux, P.

2001-12-01

The micro-pulse lidar system (MPL) was developed in the early 1990s and was the first small, eye-safe, and autonomous lidar built for fulltime monitoring of cloud and aerosol vertical distributions. In 2000, a new project using MPL systems was started at NASA Goddard Space Flight Center. This new project, the Micro-pulse Lidar Network or MPL-Net, was created to provide long-term observations of aerosol and cloud vertical profiles at key sites around the world. This is accomplished using both NASA operated sites and partnerships with other organizations owning MPL systems. The MPL-Net sites are co-located with NASA AERONET sunphotometers to provide aerosol optical depth data needed for calibration of the MPL. In addition to the long-term sites, MPL-Net provides lidar support for a limited number of field experiments and ocean cruises each year. We will present an overview of the MPL-Net project and show initial results from the first two MPL-Net sites at the South Pole and at Goddard Space Flight Center. Observations of dust layers transported from the desert regions of China, across the Pacific Ocean, to the east coast of the United States will also be shown. MPL-Net affiliated instruments were in place at the desert source region in China, on a research vessel in the Sea of Japan, at ARM sites in Alaska and Oklahoma, and finally at our home site in Maryland (GSFC) during the massive dust storms that occurred in April 2001. The MPL observations of dust layers at each location are shown in comparison to dust layers predicted using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport model (GOCART). Finally, the MPL-Net project is the primary ground-validation program for the Geo-Science Laser Altimeter System (GLAS) satellite lidar project (launch date 2002). We will present an overview demonstrating how MPL-Net results are used to help prepare the GLAS data processing algorithms and assist in the calibration/validation of the GLAS data

Initial Results from the Micro-pulse Lidar Network (MPL-Net)

Science.gov (United States)

Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Ginoux, Paul; Starr, David OC. (Technical Monitor)

2001-01-01

The micro-pulse lidar system (MPL) was developed in the early 1990s and was the first small, eye-safe, and autonomous lidar built for full time monitoring of cloud and aerosol vertical distributions. In 2000, a new project using MPL systems was started at NASA Goddard Space Flight Center. This new project, the Micro-pulse Lidar Network or MPL-Net, was created to provide long-term observations of aerosol and cloud vertical profiles at key sites around the world. This is accomplished using both NASA operated sites and partnerships with other organizations owning MPL systems. The MPL-Net sites are co-located with NASA AERONET sunphotometers to provide aerosol optical depth data needed for calibration of the MPL. In addition to the long-term sites, MPL-Net provides lidar support for a limited number of field experiments and ocean cruises each year. We will present an overview of the MPL-Net project and show initial results from the first two MPL-Net sites at the South Pole and at Goddard Space Flight Center. Observations of dust layers transported from the Gobi desert, across the Pacific Ocean, to the east coast of the United States will also be shown. MPL-Net affiliated instruments were in place at the desert source region in China, on a research vessel in the Sea of Japan, at ARM sites in Alaska and Oklahoma, and finally at our home site in Maryland (GSFC) during the massive dust storms that occurred in April 2001. The MPL observations of dust layers at each location are shown in comparison to dust layers predicted using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport model (GOCART). Finally, the MPL-Net project is the primary ground-validation program for the Geo-Science Laser Altimeter System (GLAS) satellite lidar project (launch date 2002). We will present an overview demonstrating how MPL-Net results are used to help prepare the GLAS data processing algorithms and assist in the calibration/validation of the GLAS data products.

Three dimensional computational fluid dynamic analysis of debris transport under emergency cooling water recirculation

International Nuclear Information System (INIS)

Park, Jong Woon

2010-01-01

This paper provides a computational fluid dynamic (CFD) analysis method on the evaluation of debris transport under emergency recirculation mode after loss of coolant accident of a nuclear power plant. Three dimensional reactor building floor geometrical model is constructed including flow obstacles larger than 6 inches such as mechanical components and equipments and considering various inlet flow paths from the upper reactor building such as break and spray flow. In the modeling of the inlet flows from the upper floors, effect of gravitational force was also reflected. For the precision of the analysis, 3 millions of tetrahedral-shaped meshes were generated. Reference calculation showed physically reasonable results. Sensitivity studies for mesh type and turbulence model showed very similar results to the reference case. This study provides useful information on the application of CFD to the evaluation of debris transport fraction for the design of new emergency sump filters. (orig.)

Theoretical research on working fluid selection for a high-temperature regenerative transcritical dual-loop engine organic Rankine cycle

International Nuclear Information System (INIS)

Tian, Hua; Liu, Lina; Shu, Gequn; Wei, Haiqiao; Liang, Xingyu

2014-01-01

Highlights: • Among all examined working fluids, toluene possesses the maximum W net , highest η e and η ec . • The increase of T 3 worsens system performance, decreasing W net , η e and η ec . • Condenser C LT and turbine T LT possesses the least system irreversibility. • Turbines and exhaust evaporators are optimization components. - Abstract: In this paper, a regenerative transcritical dual-loop organic Rankine cycle is proposed to recover the waste heat of the exhaust, engine coolant and all the residual heat of the HT loop. Double regenerators are adopted in this system. Transcritical cycles are used in both loops. Hexamethyldisiloxane (MM), octamethyl cyclotetrasiloxane (D 4 ), octamethyltrisiloxane (MDM), cyclohexane, toluene and n-decane are chosen as the candidate working fluids of the HT loop and R143a is chosen as the working fluid of the LT loop. Influences of inlet temperature of turbine T HT (T 3 ) on mass flow rates (m f,HT and m f,LT ), net output power (W net ), energy conversion efficiency (η ec ), volumetric expansion ratio (VER), ratio of power consumed to power output (COR) and component irreversibility are analyzed and performance comparison of these working fluids is also evaluated. Results show that toluene possesses the maximum W net (42.46 kW), highest η e (51.92%) and η ec (12.77%). The increase of T 3 worsens system performance, decreasing W net , η e and η ec . Condenser C LT and turbine T LT possess the least system irreversibility. In addition, turbines and exhaust evaporators are optimized components

Peristaltic transport of a fractional Burgers' fluid with variable viscosity through an inclined tube

Science.gov (United States)

Rachid, Hassan

2015-12-01

In the present study,we investigate the unsteady peristaltic transport of a viscoelastic fluid with fractional Burgers' model in an inclined tube. We suppose that the viscosity is variable in the radial direction. This analysis has been carried out under low Reynolds number and long-wavelength approximations. An analytical solution to the problem is obtained using a fractional calculus approach. Figures are plotted to show the effects of angle of inclination, Reynolds number, Froude number, material constants, fractional parameters, parameter of viscosity and amplitude ratio on the pressure gradient, pressure rise, friction force, axial velocity and on the mechanical efficiency.

Effect of fluid friction on interstitial fluid flow coupled with blood flow through solid tumor microvascular network.

Science.gov (United States)

Sefidgar, Mostafa; Soltani, M; Raahemifar, Kaamran; Bazmara, Hossein

2015-01-01

A solid tumor is investigated as porous media for fluid flow simulation. Most of the studies use Darcy model for porous media. In Darcy model, the fluid friction is neglected and a few simplified assumptions are implemented. In this study, the effect of these assumptions is studied by considering Brinkman model. A multiscale mathematical method which calculates fluid flow to a solid tumor is used in this study to investigate how neglecting fluid friction affects the solid tumor simulation. The mathematical method involves processes such as blood flow through vessels and solute and fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. The sprouting angiogenesis model is used for generating capillary network and then fluid flow governing equations are implemented to calculate blood flow through the tumor-induced capillary network. Finally, the two models of porous media are used for modeling fluid flow in normal and tumor tissues in three different shapes of tumors. Simulations of interstitial fluid transport in a solid tumor demonstrate that the simplifications used in Darcy model affect the interstitial velocity and Brinkman model predicts a lower value for interstitial velocity than the values that Darcy model predicts.

Performance Analysis using Coloured Petri Nets

DEFF Research Database (Denmark)

Wells, Lisa Marie

Performance is often a central issue in the design, development, and configuration of systems. It is not always enough to know that systems work properly, they must also work effectively. There are numerous studies, e.g. in the areas of computer and telecommunication systems, manufacturing......, military, health care, and transportation, that have shown that time, money, and even lives can be saved if the performance of a system is improved. Performance analysis studies are conducted to evaluate existing or planned systems, to compare alternative configurations, or to find an optimal configuration...... of a system. There are three alternative techniques for analysing the performance of a system: measurement, analytical models, and simulation models. This dissertation focuses on the the use of coloured Petri nets for simulationbased performance analysis of industrial-sized systems. Coloured Petri nets...

Prediction of transverse asymmetries in MHD ducts with zero net Hall current

International Nuclear Information System (INIS)

Swean, T.F. Jr.; Oliver, D.A.; Maxwell, C.D.; Demetriades, S.T.

1981-01-01

A new class of fluid-electrical asymmetries in MHD generator channel flow are predicted. It is shown that the existence of interelectrode asymmetries is not confined to generators in which there exists a nonzero net axial current, but rather they are induced even in the case of the Faraday generators. Also demonstrated is the impact of these asymmetries upon the generator and diffuser flow. It is concluded that in MHD generators, the net axial current in the cross plane is identically zero, while at any given point in the plane, the local Hall current density is in general nonzero

Building waste management core indicators through Spatial Material Flow Analysis: Net recovery and transport intensity indexes

Energy Technology Data Exchange (ETDEWEB)

Font Vivanco, David, E-mail: font@cml.leidenuniv.nl [Institut de Ciencia i Tecnologia Ambientals (ICTA), Departament d' Enginyeria Quimica, Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain); Institute of Environmental Sciences (CML), Leiden University, P.O. Box 9518, 2300 RA Leiden (Netherlands); Puig Ventosa, Ignasi [ENT Environment and Management, Carrer Sant Joan 39, First Floor, 08800 Vilanova i la Geltru, Barcelona (Spain); Gabarrell Durany, Xavier [Institut de Ciencia i Tecnologia Ambientals (ICTA), Departament d' Enginyeria Quimica, Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Barcelona (Spain)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Sustainability and proximity principles have a key role in waste management. Black-Right-Pointing-Pointer Core indicators are needed in order to quantify and evaluate them. Black-Right-Pointing-Pointer A systematic, step-by-step approach is developed in this study for their development. Black-Right-Pointing-Pointer Transport may play a significant role in terms of environmental and economic costs. Black-Right-Pointing-Pointer Policy action is required in order to advance in the consecution of these principles. - Abstract: In this paper, the material and spatial characterization of the flows within a municipal solid waste (MSW) management system are combined through a Network-Based Spatial Material Flow Analysis. Using this information, two core indicators are developed for the bio-waste fraction, the Net Recovery Index (NRI) and the Transport Intensity Index (TII), which are aimed at assessing progress towards policy-related sustainable MSW management strategies and objectives. The NRI approaches the capacity of a MSW management system for converting waste into resources through a systematic metabolic approach, whereas the TII addresses efficiency in terms of the transport requirements to manage a specific waste flow throughout the entire MSW management life cycle. Therefore, both indicators could be useful in assessing key MSW management policy strategies, such as the consecution of higher recycling levels (sustainability principle) or the minimization of transport by locating treatment facilities closer to generation sources (proximity principle). To apply this methodological approach, the bio-waste management system of the region of Catalonia (Spain) has been chosen as a case study. Results show the adequacy of both indicators for identifying those points within the system with higher capacity to compromise its environmental, economic and social performance and therefore establishing clear targets for policy

Horizontal ichthyoplankton tow-net system with unobstructed net opening

Science.gov (United States)

Nester, Robert T.

1987-01-01

The larval fish sampler described here consists of a modified bridle, frame, and net system with an obstruction-free net opening and is small enough for use on boats 10 m or less in length. The tow net features a square net frame attached to a 0.5-m-diameter cylinder-on-cone plankton net with a bridle designed to eliminate all obstructions forward of the net opening, significantly reducing currents and vibrations in the water directly preceding the net. This system was effective in collecting larvae representing more than 25 species of fish at sampling depths ranging from surface to 10 m and could easily be used at greater depths.

Transport of a Bose gas in 1D disordered lattices at the fluid-insulator transition.

Science.gov (United States)

Tanzi, Luca; Lucioni, Eleonora; Chaudhuri, Saptarishi; Gori, Lorenzo; Kumar, Avinash; D'Errico, Chiara; Inguscio, Massimo; Modugno, Giovanni

2013-09-13

We investigate the momentum-dependent transport of 1D quasicondensates in quasiperiodic optical lattices. We observe a sharp crossover from a weakly dissipative regime to a strongly unstable one at a disorder-dependent critical momentum. In the limit of nondisordered lattices the observations suggest a contribution of quantum phase slips to the dissipation. We identify a set of critical disorder and interaction strengths for which such critical momentum vanishes, separating a fluid regime from an insulating one. We relate our observation to the predicted zero-temperature superfluid-Bose glass transition.

Higher-moment measurements of net-kaon, net-charge and net-proton multiplicity distributions at STAR

International Nuclear Information System (INIS)

Sarkar, Amal

2014-01-01

In this paper, we report the measurements of the various moments, such as mean, standard deviation (σ), skewness (S) and kurtosis (κ) of the net-kaon, net-charge and net-proton multiplicity distributions at mid-rapidity in Au + Au collisions from √(s NN )=7.7 to 200 GeV with the STAR experiment at RHIC. This work has been done with the aim to locate the critical point on the QCD phase diagram. These moments and their products are related to the thermodynamic susceptibilities of conserved quantities such as net baryon number, net charge, and net strangeness as well as to the correlation length of the system which diverges in an ideal infinite thermodynamic system at the critical point. For a finite system, existing for a finite time, a non-monotonic behavior of these variables would indicate the presence of the critical point. Furthermore, we also present the moment products Sσ, κσ 2 of net-kaon, net-charge and net-proton multiplicity distributions as a function of collision centrality and energy. The energy and the centrality dependence of higher moments and their products have been compared with different models

Foam Transport in Porous Media - A Review

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z. F.; Freedman, Vicky L.; Zhong, Lirong

2009-11-11

transport of foam in porous media is complicated in that the number of lamellae present governs flow characteristics such as viscosity, relative permeability, fluid distribution, and interactions between fluids. Hence, foam is a non-Newtonian fluid. During transport, foam destruction and formation occur. The net result of the two processes determines the foam texture (i.e., bubble density). Some of the foam may be trapped during transport. According to the impacts of the aqueous and gas flow rates, foam flow generally has two regimes – weak and strong foam. There is also a minimum pressure gradient to initiate foam flow and a critical capillary for foam to be sustained. Similar to other fluids, the transport of foam is described by Darcy’s law with the exception that the foam viscosity is variable. Three major approaches to modeling foam transport in porous media are the empirical, semi-empirical, and mechanistic methods. Mechanistic approaches can be complete in principal but may be difficult to obtain reliable parameters, whereas empirical and semi-empirical approaches can be limited by the detail used to describe foam rheology and mobility. Mechanistic approaches include the bubble population-balance model, the network/percolation theory, the catastrophe theory, and the filtration theory. Among these methods, all were developed for modeling polyhedral foam with the exception that the method based on the filtration theory was for the ball foam (microfoam).

Surface transport in plasma-balls

Energy Technology Data Exchange (ETDEWEB)

Armas, Jay [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Bhattacharya, Jyotirmoy [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Kundu, Nilay [Harish-Chandra Research Institute,Chhatnag Road, Jhunsi, Allahabad 211019 (India)

2016-06-06

We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an application, we study the effect of temperature dependence of surface tension on some explicit examples of localized fluid configurations, which are dual to certain non-trivial black hole solutions via the AdS/CFT correspondence.

Nodal methods for problems in fluid mechanics and neutron transport

International Nuclear Information System (INIS)

Azmy, Y.Y.

1985-01-01

A new high-accuracy, coarse-mesh, nodal integral approach is developed for the efficient numerical solution of linear partial differential equations. It is shown that various special cases of this general nodal integral approach correspond to several high efficiency nodal methods developed recently for the numerical solution of neutron diffusion and neutron transport problems. The new approach is extended to the nonlinear Navier-Stokes equations of fluid mechanics; its extension to these equations leads to a new computational method, the nodal integral method which is implemented for the numerical solution of these equations. Application to several test problems demonstrates the superior computational efficiency of this new method over previously developed methods. The solutions obtained for several driven cavity problems are compared with the available experimental data and are shown to be in very good agreement with experiment. Additional comparisons also show that the coarse-mesh, nodal integral method results agree very well with the results of definitive ultra-fine-mesh, finite-difference calculations for the driven cavity problem up to fairly high Reynolds numbers

Ore-forming fluid system of bauxite in WZD area of northern Guizhou province, China

Science.gov (United States)

Cui, Tao

2017-12-01

The ore-forming fluid system of bauxite in Wuchuan-Zheng,an-Daozhen (short for WZD) Area of northern Guizhou Province was studied from the perspective of deposit formation mechanism. It was discovered that ore-forming fluids were mainly effective for transporting and leaching during the formation of bauxite. The means of transport mainly included colloidal transport, suspended transport and gravity flow transport. In the course of their leaching, fluids had a range of chemical reactions, as a result of which elements such as silicon and iron migrated downwards. In this process, properties of fluids changed as well.

Role of Aquaporin Water Channels in Airway Fluid Transport, Humidification, and Surface Liquid Hydration

Science.gov (United States)

Song, Yuanlin; Jayaraman, Sujatha; Yang, Baoxue; Matthay, Michael A.; Verkman, A.S.

2001-01-01

Several aquaporin-type water channels are expressed in mammalian airways and lung: AQP1 in microvascular endothelia, AQP3 in upper airway epithelia, AQP4 in upper and lower airway epithelia, and AQP5 in alveolar epithelia. Novel quantitative methods were developed to compare airway fluid transport–related functions in wild-type mice and knockout mice deficient in these aquaporins. Lower airway humidification, measured from the moisture content of expired air during mechanical ventilation with dry air through a tracheotomy, was 54–56% efficient in wild-type mice, and reduced by only 3–4% in AQP1/AQP5 or AQP3/AQP4 double knockout mice. Upper airway humidification, measured from the moisture gained by dry air passed through the upper airways in mice breathing through a tracheotomy, decreased from 91 to 50% with increasing ventilation from 20 to 220 ml/min, and reduced by 3–5% in AQP3/AQP4 knockout mice. The depth and salt concentration of the airway surface liquid in trachea was measured in vivo using fluorescent probes and confocal and ratio imaging microscopy. Airway surface liquid depth was 45 ± 5 μm and [Na+] was 115 ± 4 mM in wild-type mice, and not significantly different in AQP3/AQP4 knockout mice. Osmotic water permeability in upper airways, measured by an in vivo instillation/sample method, was reduced by ∼40% by AQP3/AQP4 deletion. In doing these measurements, we discovered a novel amiloride-sensitive isosmolar fluid absorption process in upper airways (13% in 5 min) that was not affected by aquaporin deletion. These results establish the fluid transporting properties of mouse airways, and indicate that aquaporins play at most a minor role in airway humidification, ASL hydration, and isosmolar fluid absorption. PMID:11382807

Brain washing : Transport of cerebral extracellular fluids and solutes

NARCIS (Netherlands)

Bedussi, B.

2017-01-01

Regulation of extracellular volume and fluid composition provides a robust microenvironment for brain cells. In peripheral tissue, fluid surplus and solutes are removed from the interstitium via drainage into lymphatic channels. Since the central nervous system lacks a proper lymphatic vasculature,

Performance Analysis and Working Fluid Selection of a Supercritical Organic Rankine Cycle for Low Grade Waste Heat Recovery

Directory of Open Access Journals (Sweden)

Yourong Li

2012-08-01

Full Text Available The performance analysis of a supercritical organic Rankine cycle system driven by exhaust heat using 18 organic working fluids is presented. Several parameters, such as the net power output, exergy efficiency, expander size parameter (SP, and heat exchanger requirement of evaporator and the condenser, were used to evaluate the performance of this recovery cycle and screen the working fluids. The results reveal that in most cases, raising the expander inlet temperature is helpful to improve the net power output and the exergy efficiency. However, the effect of the expander inlet pressure on those parameters is related to the expander inlet temperature and working fluid used. Either lower expander inlet temperature and pressure, or higher expander inlet temperature and pressure, generally makes the net power output more. Lower expander inlet temperature results in larger total heat transfer requirement and expander size. According to the screening criteria of both the higher output and the lower investment, the following working fluids for the supercritical ORC system are recommended: R152a and R143a.

An integrated methodology for characterizing flow and transport processes in fractured rock

International Nuclear Information System (INIS)

Wu, Yu-Shu

2007-01-01

To investigate the coupled processes involved in fluid and heat flow and chemical transport in the highly heterogeneous, unsaturated-zone (UZ) fractured rock of Yucca Mountain, we present an integrated modeling methodology. This approach integrates a wide variety of moisture, pneumatic, thermal, and geochemical isotopic field data into a comprehensive three-dimensional numerical model for modeling analyses. The results of field applications of the methodology show that moisture data, such as water potential and liquid saturation, are not sufficient to determine in situ percolation flux, whereas temperature and geochemical isotopic data provide better constraints to net infiltration rates and flow patterns. In addition, pneumatic data are found to be extremely valuable in estimating large-scale fracture permeability. The integration of hydrologic, pneumatic, temperature, and geochemical data into modeling analyses is thereby demonstrated to provide a practical modeling approach for characterizing flow and transport processes in complex fractured formations

Calcium transport in turtle bladder

International Nuclear Information System (INIS)

Sabatini, S.; Kurtzman, N.A.

1987-01-01

Unidirectional 45 Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J net Ca ) was secretory (serosa to mucosa). Ouabain reversed J net Ca to an absorptive flux. Amiloride reduced both fluxes such that J net Ca was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J net Ca decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J net Ca was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45 Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca 2+ -ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na + -K + -ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

Edge-Localized mode control and transport generated by externally applied magnetic perturbations

International Nuclear Information System (INIS)

Joseph, I.

2012-01-01

This article reviews the subject of edge localized mode (ELM) control using externally applied magnetic perturbations and proposes theoretical mechanisms that may be responsible for the induced transport changes. The first question that must be addressed is: what is the structure of magnetic field within the plasma? Although initial hypotheses focused on the possibility of the creation of a region of stochastic field lines at the tokamak edge, drift magnetohydrodynamics theory predicts that magnetic reconnection is strongly suppressed over the region of the pedestal with steep gradients and fast perpendicular rotation. Reconnection can only occur near the location where the perpendicular electron velocity vanishes, and hence the electron impedance nearly vanishes, or near the foot of the pedestal, where the plasma is sufficiently cold and resistive. The next question that must be addressed is: which processes are responsible for the observed transport changes, nonlinearity, turbulence, or stochasticity? Over the pedestal region where ions and electrons rotate in opposite directions relative to the perturbation, the quasilinear Lorentz force decelerates the electron fluid and accelerates the ion fluid. The quasilinear magnetic flutter flux is proportional to the force and produces an outward convective transport that can be significant. Over the pedestal region where the E x B flow and the electrons rotate in opposite directions relative to the perturbation, magnetic islands with a width on the order of the ion gyroradius can directly radiate drift waves. In addition, the combination of quasilinear electron transport and ion viscous transport can lead to a large net particle flux. Since there are many transport mechanisms that may be active simultaneously, it is important to determine which physical mechanisms are responsible for ELM control and to predict the scaling to future devices (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Hyperacid volcano-hydrothermal fluids from Copahue volcano, Argentina: Analogs for "subduction zone fluids"?

Science.gov (United States)

Varekamp, J. C.

2007-12-01

Hyperacid concentrated Chlorine-Sulfate brines occur in many young arc volcanoes, with pH values Copahue volcanic system (Argentina) suggest reservoir temperatures of 175-300 oC, whereas the surface fluids do not exceed local boiling temperatures. These fluids are generated at much lower P-T conditions than fluids associated with a dehydrating subducted sediment complex below arc volcanoes, but their fundamental chemical compositions may have similarities. Incompatible trace element, major element concentrations and Pb isotope compositions of the fluids were used to determine the most likely rock protoliths for these fluids. Mean rock- normalized trace element diagrams then indicate which elements are quantitatively extracted from the rocks and which are left behind or precipitated in secondary phases. Most LILE show flat rock-normalized patterns, indicating close to congruent dissolution, whereas Ta-Nb-Ti show strong depletions in the rock-normalized diagrams. These HFSE are either left behind in the altered rock protolith or were precipitated along the way up. The behavior of U and Th is almost identical, suggesting that in these low pH fluids with abundant ligands Th is just as easily transported as U, which is not the case in more dilute, neutral fluids. Most analyzed fluids have steeper LREE patterns than the rocks and have negative Eu anomalies similar to the rocks. Fluids that interacted with newly intruded magma e.g., during the 2000 eruption, have much less pronounced Eu anomalies, which was most likely caused by the preferential dissolution of plagioclase when newly intruded magma interacted with the acid fluids. The fluids show a strong positive correlation between Y and Cd (similar to MORB basalts, Yi et al., JGR, 2000), suggesting that Cd is mainly a rock-derived element that may not show chalcophilic behavior. The fluids are strongly enriched (relative to rock) in As, Zn and Pb, suggesting that these elements were carried with the volcanic gas phase

Development of Network Interface Cards for TRIDAQ systems with the NaNet framework

International Nuclear Information System (INIS)

Ammendola, R.; Biagioni, A.; Cretaro, P.; Frezza, O.; Cicero, F. Lo; Lonardo, A.; Martinelli, M.; Paolucci, P.S.; Pastorelli, E.; Simula, F.; Valente, P.; Vicini, P.; Lorenzo, S. Di; Piandani, R.; Pontisso, L.; Sozzi, M.; Fiorini, M.; Neri, I.; Lamanna, G.; Rossetti, D.

2017-01-01

NaNet is a framework for the development of FPGA-based PCI Express (PCIe) Network Interface Cards (NICs) with real-time data transport architecture that can be effectively employed in TRIDAQ systems. Key features of the architecture are the flexibility in the configuration of the number and kind of the I/O channels, the hardware offloading of the network protocol stack, the stream processing capability, and the zero-copy CPU and GPU Remote Direct Memory Access (RDMA). Three NIC designs have been developed with the NaNet framework: NaNet-1 and NaNet-10 for the CERN NA62 low level trigger and NaNet 3 for the KM3NeT-IT underwater neutrino telescope DAQ system. We will focus our description on the NaNet-10 design, as it is the most complete of the three in terms of capabilities and integrated IPs of the framework.

Net Analyte Signal Standard Additions Method for Simultaneous Determination of Sulfamethoxazole and Trimethoprim in Pharmaceutical Formulations and Biological Fluids

OpenAIRE

Givianrad, M. H.; Mohagheghian, M.

2012-01-01

The applicability of a novel net analyte signal standard addition method (NASSAM) to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim was verified by UV-visible spectrophotometry. The results confirmed that the net analyte signal standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. Moreover, applying the net analyte signal standard a...

An Efficient Translation of Timed-Arc Petri Nets to Networks of Timed Automata

DEFF Research Database (Denmark)

Byg, Joakim; Jørgensen, Kenneth Yrke; Srba, Jiri

2009-01-01

Bounded timed-arc Petri nets with read-arcs were recently proven equivalent to networks of timed automata, though the Petri net model cannot express urgent behaviour and the described mutual trans- lations are rather inefficient. We propose an extension of timed-arc Petri nets with invariants...... to enforce urgency and with transport arcs to generalise the read-arcs. We also describe a novel translation from the extended timed-arc Petri net model to networks of timed automata. The translation is implemented in the tool TAPAAL and it uses UPPAAL as the verification engine. Our experiments confirm...... the efficiency of the translation and in some cases the translated models verify significantly faster than the native UPPAAL models do....

Annual and Seasonal Mean Net Evaporation Rates of the Red Sea Water during Jan 1958 - Dec 2007

OpenAIRE

Nassir, Sahbaldeen Abdulaziz

2012-01-01

Data set including sea level, temperature, salinity, and current from Simple Ocean Data Assimilation (SODA) is used in this study to estimate the mean net annually and seasonally evaporation rates. Then wind data is used to examine its impact on the evaporation. This work calculated the seasonal and annual evaporation rates based on assumption of that there is no net mass transport (balanced). Hence, the difference in the transport supposed to be equal to the water that has eva...

Debris transport evaluation during the blow-down phase of a LOCA using computational fluid dynamics

International Nuclear Information System (INIS)

Park, Jong Pil; Jeong, Ji Hwan; Kim, Won Tae; Kim, Man Woong; Park, Ju Yeop

2011-01-01

Highlights: → We conducted CFD simulation on the spreading of the coolant in the containment after a break of the hot leg. It is used to estimate the dispersion of the debris within the containment. → It was assumed that the small and fine debris is transported by the discharge flow so that a fraction of the small and fine debris transport can be estimated based on the amount of water. → The break flow was assumed to be a homogeneous two-phase mixture without phase separation. Isenthalpic expansion of the break flow was used to specify the inlet boundary condition of the break flow. → The fraction of the small and fine debris transported to the upper part is 73%; this value is close to the value calculated using 1D lumped-parameter codes by the USNRC and the KINS, respectively, while 48% more than the value shown in the NEI 04-07. - Abstract: The performance of the emergency recirculation water sump under the influence of debris accumulation following a loss-of-coolant accident (LOCA) has long been of safety concern. Debris generation and transport during a LOCA are significantly influenced by the characteristics of the ejected coolant flow. One-dimensional analyses previously have been attempted to evaluate the debris transport during the blow-down phase but the transport evaluation still has large uncertainties. In this work, a computational fluid dynamics (CFD) analysis was utilized to evaluate small and fine debris transport during the blow-down phase of a pressurized water reactor, OPR1000. The coolant ejected from the ruptured hot-leg was assumed to expand in an isenthalpic process. The transport of small and fine debris was assumed to be dominated by water-borne transport, and the transport fractions for the upper and lower parts of the containment were quantified based on the CFD analysis. It was estimated that 73% of small and fine debris is transported to the upper part of the containment. This value is close to the values estimated by nuclear

Atomistic Modeling of the Fluid-Solid Interface in Simple Fluids

Science.gov (United States)

Hadjiconstantinou, Nicolas; Wang, Gerald

2017-11-01

Fluids can exhibit pronounced structuring effects near a solid boundary, typically manifested in a layered structure that has been extensively shown to directly affect transport across the interface. We present and discuss several results from molecular-mechanical modeling and molecular-dynamics (MD) simulations aimed at characterizing the structure of the first fluid layer directly adjacent to the solid. We identify a new dimensionless group - termed the Wall number - which characterizes the degree of fluid layering, by comparing the competing effects of wall-fluid interaction and thermal energy. We find that in the layering regime, several key features of the first layer layer - including its distance from the solid, its width, and its areal density - can be described using mean-field-energy arguments, as well as asymptotic analysis of the Nernst-Planck equation. For dense fluids, the areal density and the width of the first layer can be related to the bulk fluid density using a simple scaling relation. MD simulations show that these results are broadly applicable and robust to the presence of a second confining solid boundary, different choices of wall structure and thermalization, strengths of fluid-solid interaction, and wall geometries.

Research into the Physiology of Cerebrospinal Fluid Reaches a New Horizon: Intimate Exchange between Cerebrospinal Fluid and Interstitial Fluid May Contribute to Maintenance of Homeostasis in the Central Nervous System.

Science.gov (United States)

Matsumae, Mitsunori; Sato, Osamu; Hirayama, Akihiro; Hayashi, Naokazu; Takizawa, Ken; Atsumi, Hideki; Sorimachi, Takatoshi

2016-07-15

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.

Aerosol transport simulations in indoor and outdoor environments using computational fluid dynamics (CFD)

Science.gov (United States)

Landazuri, Andrea C.

This dissertation focuses on aerosol transport modeling in occupational environments and mining sites in Arizona using computational fluid dynamics (CFD). The impacts of human exposure in both environments are explored with the emphasis on turbulence, wind speed, wind direction and particle sizes. Final emissions simulations involved the digitalization process of available elevation contour plots of one of the mining sites to account for realistic topographical features. The digital elevation map (DEM) of one of the sites was imported to COMSOL MULTIPHYSICSRTM for subsequent turbulence and particle simulations. Simulation results that include realistic topography show considerable deviations of wind direction. Inter-element correlation results using metal and metalloid size resolved concentration data using a Micro-Orifice Uniform Deposit Impactor (MOUDI) under given wind speeds and directions provided guidance on groups of metals that coexist throughout mining activities. Groups between Fe-Mg, Cr-Fe, Al-Sc, Sc-Fe, and Mg-Al are strongly correlated for unrestricted wind directions and speeds, suggesting that the source may be of soil origin (e.g. ore and tailings); also, groups of elements where Cu is present, in the coarse fraction range, may come from mechanical action mining activities and saltation phenomenon. Besides, MOUDI data under low wind speeds (Computational Fluid Dynamics can be used as a source apportionment tool to identify areas that have an effect over specific sampling points and susceptible regions under certain meteorological conditions, and these conclusions can be supported with inter-element correlation matrices and lead isotope analysis, especially since there is limited access to the mining sites. Additional results concluded that grid adaption is a powerful tool that allows to refine specific regions that require lots of detail and therefore better resolve flow detail, provides higher number of locations with monotonic convergence than the

Icodextrin's effects on peritoneal transport

NARCIS (Netherlands)

Krediet, R. T.; Ho-Dac-Pannekeet, M. M.; Imholz, A. L.; Struijk, D. G.

1997-01-01

OBJECTIVE: To give a survey of the principles of peritoneal fluid transport in general, followed by an analysis of the effects of icodextrin on the transport of fluid and solutes. DESIGN: A review of the literature and of data on the effects of icodextrin in continuous ambulatory peritoneal dialysis

Computational fluid dynamics simulation of transport and retention of nanoparticle in saturated sand filters

International Nuclear Information System (INIS)

Hassan, Ashraf Aly; Li, Zhen; Sahle-Demessie, Endalkachew; Sorial, George A.

2013-01-01

Highlights: ► Breakthrough curves used to study fate of NPs in slow sand filters (SSF). ► CFD simulate transport, attachment/detachment of NPs in SSFs. ► CFD predicted spatial and temporal changes for transient concentrations of NPs. ► CFD predicts low concentrations and steady NP influx would not be retained by SSFs. ► Pulse input is retained with outlet concentration of 0.2% of the inlet. -- Abstract: Experimental and computational investigation of the transport parameters of nanoparticles (NPs) flowing through porous media has been made. This work intends to develop a simulation applicable to the transport and retention of NPs in saturated porous media for investigating the effect of process conditions and operating parameters such, as ion strength, and filtration efficiency. Experimental data obtained from tracer and nano-ceria, CeO 2 , breakthrough studies were used to characterize dispersion of nanoparticle with the flow and their interaction with sand packed columns with different heights. Nanoparticle transport and concentration dynamics were solved using the Eulerian computational fluid dynamics (CFD) solver ANSYS/FLUENT ® based on a scaled down flow model. A numerical study using the Navier–Stokes equation with second order interaction terms was used to simulate the process. Parameters were estimated by fitting tracer, experimental NP transport data, and interaction of NP with the sand media. The model considers different concentrations of steady state inflow of NPs and different amounts of spike concentrations. Results suggest that steady state flow of dispersant-coated NPs would not be retained by a sand filter, while spike concentrations could be dampened effectively. Unlike analytical solutions, the CFD allows estimating flow profiles for structures with complex irregular geometry and uneven packing

Computational fluid dynamics simulation of transport and retention of nanoparticle in saturated sand filters

Energy Technology Data Exchange (ETDEWEB)

Hassan, Ashraf Aly [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Li, Zhen [School of Energy, Environmental, Biological, and Medical Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH (United States); Sahle-Demessie, Endalkachew, E-mail: sahle-demessie.endalkachew@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Sorial, George A. [School of Energy, Environmental, Biological, and Medical Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH (United States)

2013-01-15

Highlights: ► Breakthrough curves used to study fate of NPs in slow sand filters (SSF). ► CFD simulate transport, attachment/detachment of NPs in SSFs. ► CFD predicted spatial and temporal changes for transient concentrations of NPs. ► CFD predicts low concentrations and steady NP influx would not be retained by SSFs. ► Pulse input is retained with outlet concentration of 0.2% of the inlet. -- Abstract: Experimental and computational investigation of the transport parameters of nanoparticles (NPs) flowing through porous media has been made. This work intends to develop a simulation applicable to the transport and retention of NPs in saturated porous media for investigating the effect of process conditions and operating parameters such, as ion strength, and filtration efficiency. Experimental data obtained from tracer and nano-ceria, CeO{sub 2}, breakthrough studies were used to characterize dispersion of nanoparticle with the flow and their interaction with sand packed columns with different heights. Nanoparticle transport and concentration dynamics were solved using the Eulerian computational fluid dynamics (CFD) solver ANSYS/FLUENT{sup ®} based on a scaled down flow model. A numerical study using the Navier–Stokes equation with second order interaction terms was used to simulate the process. Parameters were estimated by fitting tracer, experimental NP transport data, and interaction of NP with the sand media. The model considers different concentrations of steady state inflow of NPs and different amounts of spike concentrations. Results suggest that steady state flow of dispersant-coated NPs would not be retained by a sand filter, while spike concentrations could be dampened effectively. Unlike analytical solutions, the CFD allows estimating flow profiles for structures with complex irregular geometry and uneven packing.

Transport studies for ignition experiments

International Nuclear Information System (INIS)

Nocentini, A.; Schultz, G.

1990-07-01

The results of a predictive study of plasma energy confinement in IGNITOR, performed with a 1 1/2-D transport code and the Tang an Redi transport model, are reported. For comparison, performance predictions for NET adopting similar assumptions on plasma transport are also presented. (author) 16 figs., 5 tabs., 13 refs

Mathematical modeling for laminar flow of power law fluid in porous media

Energy Technology Data Exchange (ETDEWEB)

Silva, Renato A.; Mesquita, Maximilian S. [Universidade Federal do Espirito Santo (UFES), Sao Mateus, ES (Brazil). Centro Universitario Norte do Espirito Santo. Dept. de Engenharias e Computacao

2010-07-01

In this paper, the macroscopic equations for laminar power-law fluid flow is obtained for a porous medium starting from traditional equations (Navier-Stokes). Then, the volume averaging is applied in traditional transport equations with the power-law fluid model. This procedure leads to macroscopic transport equations set for non-Newtonian fluid. (author)

Chemical mass transport between fluid fine tailings and the overlying water cover of an oil sands end pit lake

Science.gov (United States)

Dompierre, Kathryn A.; Barbour, S. Lee; North, Rebecca L.; Carey, Sean K.; Lindsay, Matthew B. J.

2017-06-01

Fluid fine tailings (FFT) are a principal by-product of the bitumen extraction process at oil sands mines. Base Mine Lake (BML)—the first full-scale demonstration oil sands end pit lake (EPL)—contains approximately 1.9 × 108 m3 of FFT stored under a water cover within a decommissioned mine pit. Chemical mass transfer from the FFT to the water cover can occur via two key processes: (1) advection-dispersion driven by tailings settlement; and (2) FFT disturbance due to fluid movement in the water cover. Dissolved chloride (Cl) was used to evaluate the water cover mass balance and to track mass transport within the underlying FFT based on field sampling and numerical modeling. Results indicated that FFT was the dominant Cl source to the water cover and that the FFT is exhibiting a transient advection-dispersion mass transport regime with intermittent disturbance near the FFT-water interface. The advective pore water flux was estimated by the mass balance to be 0.002 m3 m-2 d-1, which represents 0.73 m of FFT settlement per year. However, the FFT pore water Cl concentrations and corresponding mass transport simulations indicated that advection rates and disturbance depths vary between sample locations. The disturbance depth was estimated to vary with location between 0.75 and 0.95 m. This investigation provides valuable insight for assessing the geochemical evolution of the water cover and performance of EPLs as an oil sands reclamation strategy.

A reactive transport modelling approach to assess the leaching potential of hydraulic fracturing fluids associated with coal seam gas extraction

Science.gov (United States)

Mallants, Dirk; Simunek, Jirka; Gerke, Kirill

2015-04-01

Coal Seam Gas production generates large volumes of "produced" water that may contain compounds originating from the use of hydraulic fracturing fluids. Such produced water also contains elevated concentrations of naturally occurring inorganic and organic compounds, and usually has a high salinity. Leaching of produced water from storage ponds may occur as a result of flooding or containment failure. Some produced water is used for irrigation of specific crops tolerant to elevated salt levels. These chemicals may potentially contaminate soil, shallow groundwater, and groundwater, as well as receiving surface waters. This paper presents an application of scenario modelling using the reactive transport model for variably-saturated media HP1 (coupled HYDRUS-1D and PHREEQC). We evaluate the fate of hydraulic fracturing chemicals and naturally occurring chemicals in soil as a result of unintentional release from storage ponds or when produced water from Coal Seam Gas operations is used in irrigation practices. We present a review of exposure pathways and relevant hydro-bio-geo-chemical processes, a collation of physico-chemical properties of organic/inorganic contaminants as input to a set of generic simulations of transport and attenuation in variably saturated soil profiles. We demonstrate the ability to model the coupled processes of flow and transport in soil of contaminants associated with hydraulic fracturing fluids and naturally occurring contaminants.

Coupled Fluid, Energy, and Solute Transport (CFEST) model: Formulation and user's manual

International Nuclear Information System (INIS)

Gupta, S.K.; Cole, C.R.; Kincaid, C.T.; Monti, A.M.

1987-10-01

The CFEST (Coupled Fluid, Energy, and Solute Transport) code has been developed to analyze coupled hydrologic, thermal, and solute transport processes. It treats single-pahse Darcy ground-water flow in a horizontal or vertical plane, or in fully three-dimensional space under nonisothermal conditions. The code has the capability to model discontinuous and continuous layering, time-dependent and constant sources/sinks, and transient as well as steady-stae ground-water flow. The code offers a wide choice of boundary conditions such as precsribed heads, nodal injection or withdrawal, constant or spatially varying infiltration rates, and welemental source/sink. Initial conditions for the flow analysis can be prescribed pressure or hydraulic head. The heterogeneity in aquifer permeability and porosity can be described by geologic unit or explicity for given elements. Three-dimensional elelments are generated from user-defined well logs at each surface node. To facilitate interaction between disciplines, support programs are provided to plot the finite element grid, well logs, contour maps of input and output parameters, and vertical cross sections. Ground-water travel paths and times and volumetric rates from a specified point can be determined from support programs. This report includes governing partial differential equations, finite element formulation, a use's manual, verification test examples, sample problems, and source listings. 36 refs., 121 figs., 36 tabs

CLIMATIC FORECASTING OF NET INFILTRATION AT YUCCA MOUNTAIN, USING ANALOGUE METEOROLOGICAL DATA

International Nuclear Information System (INIS)

B. Faybishenko

2005-01-01

Net infiltration is a key hydrologic parameter that controls the rate of deep percolation through the unsaturated zone, the groundwater recharge, radionuclide transport, and seepage into the underground tunnels. Because net infiltration is largely affected by climatic conditions, future changes in climatic conditions will potentially alter net infiltration. The objectives of this presentation are to: (1) Present a conceptual model and a semi-empirical approach for regional, climatic forecasting of net infiltration, based on the precipitation and temperature data from analogue meteorological stations, and (2) Demonstrate the results of forecasting net infiltration for future climates--interglacial, monsoon and glacial--over the Yucca Mountain region for the period of 500,000 years. Calculations of the net infiltration were performed using a modified Budyko's water-balance model, for which potential evapotranspiration was evaluated from the temperature-based Thornthwaite formula. (Both Budyko's and Thornthwaite's formulae have been used broadly in hydrological studies.) The results of calculations were used for ranking net infiltration, along with the aridity and precipitation-effectiveness (P-E) indexes, for future climatic scenarios. Using this approach, we determined a general trend of increasing net infiltration from the present-day (interglacial) climate to monsoon, intermediate (glacial transition), and then to the glacial climate. Ranking of the aridity and P-E indexes is practically the same as that of net infiltration. The validation of the computed net infiltration rates yielded a good match with other field and modeling study results of groundwater recharge and net infiltration evaluation

Radio-frequency heating and neutral atom transport in a fluid-magnetohydrodynamic treatment of burning tokamak plasmas

International Nuclear Information System (INIS)

Conn, R.W.; Mau, T.K.; Prinja, A.K.

1983-01-01

A physical model for the space and time evolution of the primary parameters of ordinary and burning tokamak plasmas is described by employing a fluid plasma treatment coupled to a magnetohydrodynamic equilibrium description, the solution to the appropriate Maxwell equations, and the solution of the linear transport equation describing neutral atom transport in plasmas. The specific problems of plasma heating by ion cyclotron radiofrequency (ICRF) waves and neutral atom transport in the plasma edge and in complicated geometrical components such as divertor channels or pumped limiter structures are analyzed. A theoretical, onedimensional slab model of ICRF heating at ω = 2ω/SUB cD/ is developed and applied to determine the space-time response of tokamak plasmas. Generally, strong single-pass absorption is found for high-density, high (β) plasmas using a low k 11 spectrum (0.05 to 0.1 cm -1 ) although for (β > 1%, electron Landau damping becomes important. Deterministic and Monte Carlo methods to solve the neutral atom transport problem are described. Specific application to determine the spectrum of neutral atoms emerging from the duct of a pump limiter shows it to be hard (mean energy > 20 eV), indicating very incomplete energy thermalization. Uncertainties are identified in the overall problem of dynamic burning plasma analysis caused by the complexity of the problem itself and by uncertainties in fundamental areas such as plasma transport coefficients, stability, and plasma edge physics

Fluid Mechanics of Blood Clot Formation.

Science.gov (United States)

Fogelson, Aaron L; Neeves, Keith B

2015-01-01

Intravascular blood clots form in an environment in which hydrodynamic forces dominate and in which fluid-mediated transport is the primary means of moving material. The clotting system has evolved to exploit fluid dynamic mechanisms and to overcome fluid dynamic challenges to ensure that clots that preserve vascular integrity can form over the wide range of flow conditions found in the circulation. Fluid-mediated interactions between the many large deformable red blood cells and the few small rigid platelets lead to high platelet concentrations near vessel walls where platelets contribute to clotting. Receptor-ligand pairs with diverse kinetic and mechanical characteristics work synergistically to arrest rapidly flowing cells on an injured vessel. Variations in hydrodynamic stresses switch on and off the function of key clotting polymers. Protein transport to, from, and within a developing clot determines whether and how fast it grows. We review ongoing experimental and modeling research to understand these and related phenomena.

Petri Nets

Indian Academy of Sciences (India)

In a computer system, for example, typical discrete events ... This project brought out a series of influential reports on Petri net theory in the mid and late ... Technology became a leading centre for Petri net research and from then on, Petri nets ...

Placental transport of radionuclides. Terminal report, May 1, 1973--July 31, 1975

International Nuclear Information System (INIS)

Kronfeld, D.S.

1977-08-01

Four successful experiments were conducted with tritiated water on pregnant sheep. This came into equilibrium between fetal and maternal circulations within 60 seconds after injection into the ewe or the fetus. The estimates of total water transport rate averaged 85% of the daily water intake. Six successful experiments were conducted with 3 H- and 14 C-glucose on pregnant ewes. The results for glucose space and transport rate in the ewes agree closely with previously published data. The fetal glucose pool size was large, presumably reflecting the relatively large volume of fetal-placental fluids in exchange with fetal blood. Six successful experiments were conducted with 45 Ca and 47 Ca for 5 days or more on pregnant ewes. The smallest compartment size of exchangeable calcium in mother and fetus were about 2 to 6 hours duration, and the net daily gain of calcium by the fetus was just slightly less in the chronic than in the acute experiments, 0.75 and 0.83 g/day respectively

Blood epididymal barrier to [3H]-inulin in intact and vasectomized hamsters

International Nuclear Information System (INIS)

Turner, T.T.; D'Addario, D.A.; Howards, S.S.

1981-01-01

The net transport of [ 3 H]-inulin into the fluids of the hamster seminiferous and caput, corpus, and cauda epididymal tubules was examined in both intact animals and those vasectomized 10 months previously. Mean isotope concentrations in reproductive tract tubule fluids did not exceeded 10 per cent of blood plasma isotope concentrations during the experiment. There were no significant differences in net transport of [ 3 H]-inulin into any of the tubule fluids sampled. Ten months after vasectomy, the seminiferous tubule, and all regions of the epididymal tubule retain the capacity to exclude [ 3 H]-insulin. Thus in the hamster 10 months after vasectomy, the blood testis and blood epididymal barriers to inulin are intact

Dynamic dielectrophoresis model of multi-phase ionic fluids.

Directory of Open Access Journals (Sweden)

Ying Yan

Full Text Available Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

Dynamic dielectrophoresis model of multi-phase ionic fluids.

Science.gov (United States)

Yan, Ying; Luo, Jing; Guo, Dan; Wen, Shizhu

2015-01-01

Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

H+, Water and Urea Transport in the Inner Medullary Collecting Duct and Their Role in the Prevention and Pathogenesis of Renal Stone Disease

Science.gov (United States)

Wall, Susan M.; Klein, Janet D.

2008-09-01

The inner medullary collecting duct (IMCD) is the final site within the kidney for the reabsorption of urea, water and electrolytes and for the secretion of H+ before the luminal fluid becomes the final urine. Transporters expressed in the IMCD contribute to the generation of the large ion gradients that exist between the interstitium and the collecting duct lumen. Thus, the luminal fluid within the human IMCD can reach an osmolality of 1200 mOsm/kg H2O and a pH of 4. This ability of the human nephron to concentrate and acidify the urine might predispose to stone formation. However, under treatment conditions that predispose to stone formation, such as during hypercalciuria, the kidney mitigates stone formation by reducing solute concentration by reducing H2O reabsorption. Moreover, the kidney attenuates stone formation by tightly controlling acid-base balance, which prevents the bone loss, hypocitraturia and hypercalciuria observed during metabolic acidosis by augmenting net H+ excretion by tightly regulating H+ transporter function and through luminal buffering, particularly with NH3. This article will review the ion transporters present in the mammalian IMCD and their role in the prevention and in the pathogenesis of renal stone formation.

Advances in Environmental Fluid Mechanics

CERN Document Server

Mihailovic, Dragutin T

2010-01-01

Environmental fluid mechanics (EFM) is the scientific study of transport, dispersion and transformation processes in natural fluid flows on our planet Earth, from the microscale to the planetary scale. This book brings together scientists and engineers working in research institutions, universities and academia, who engage in the study of theoretical, modeling, measuring and software aspects in environmental fluid mechanics. It provides a forum for the participants, and exchanges new ideas and expertise through the presentations of up-to-date and recent overall achievements in this field.

The equivalency between logic Petri workflow nets and workflow nets.

Science.gov (United States)

Wang, Jing; Yu, ShuXia; Du, YuYue

2015-01-01

Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented.

The Equivalency between Logic Petri Workflow Nets and Workflow Nets

Science.gov (United States)

Wang, Jing; Yu, ShuXia; Du, YuYue

2015-01-01

Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented. PMID:25821845

Characteristics of injury and recovery of net NO3- transport of barley seedlings from treatments of NaCl

Science.gov (United States)

Klobus, G.; Ward, M. R.; Huffaker, R. C.

1988-01-01

The nature of the injury and recovery of nitrate uptake (net uptake) from NaCl stress in young barley (Hordeum vulgare L, var CM 72) seedlings was investigated. Nitrate uptake was inhibited rapidly by NaCl, within 1 minute after exposure to 200 millimolar NaCl. The duration of exposure to saline conditions determined the time of recovery of NO3- uptake from NaCl stress. Recovery was dependent on the presence of NO3- and was inhibited by cycloheximide, 6-methylpurine, and cerulenin, respective inhibitors of protein, RNA, and sterol/fatty acid synthesis. These inhibitors also prevented the induction of the NO3- uptake system in uninduced seedlings. Uninduced seedlings exhibited endogenous NO3- transport activity that appeared to be constitutive. This constitutive activity was also inhibited by NaCl. Recovery of constitutive NO3- uptake did not require the presence of NO3-.

Dynamics of radiating fluids

International Nuclear Information System (INIS)

Mihalas, D.; Weaver, R.

1982-01-01

The purpose of this paper is to give an overview of the role of radiation in the transport of energy and momentum in a combined matter-radiation fluid. The transport equation for a moving radiating fluid is presented in both a fully Eulerian and a fully Lagrangian formulation, along with conservation equations describing the dynamics of the fluid. Special attention is paid to the problem of deriving equations that are mutually consistent in each frame, and between frames, to 0(v/c). A detailed analysis is made to show that in situations of broad interest, terms that are formally of 0(v/c) actually dominate the solution, demonstrating that it is essential (1) to pay scrupulous attention to the question of the frame dependence in formulating the equations, and (2) to solve the equations to 0(v/c) in quite general circumstances. These points are illustrated in the context of the nonequilibrium radiation diffusion limit, and a sketch of how the Lagrangian equations are to be solved is presented

An experimental study on the effects of rectifiers on fluid flow

International Nuclear Information System (INIS)

Kawashima, G.

1985-01-01

This paper reports studies of various combinations of rectifiers and rectifying nets to measure fluid flow and in particular, the measurement of the flow through an orifice or nozzle, since they help to shorten the inlet length

Flask fluid flow simulation using CFD

International Nuclear Information System (INIS)

Swindlehurst, W.E.; Livesey, E.; Worthington, D.

1989-01-01

BNFL and its subsidiary Company, PNTL, design and operate waterfilled LWR fuel transport flasks for the international transport of irradiated fuel. Although some 150 flasks are currently in operation, new flask designs are being developed. As part of the supporting R and D program, Computational Fluid Dynamics (CFD) codes are being investigated as a means of predicting fluid movements and temperatures within the complex internal geometry of flasks. The ability to simulate fluid flow is particularly important when convection heat transfer is significant. Although obviously relevant to water filled flasks, the technique is applicable to dry flask thermal assessments (where experience shows that convection heat transfer is often underestimated). Computational Fluid Dynamics has emerged in recent years as an important technique in engineering design and safety assessments. Cheaper computing and the development of general CFD codes allows complex engineering structures to be analyzed. However, because of this complexity, it is essential that the application and associated modeling assumptions are critically reviewed. To assess the ability of a CFD code to model flask internals, the code PHOENICS has been used to model the fluid movements in a BNFL Excellox-type flask and the results compared with test data

Method and apparatus for preventing agglomeration within fluid hydrocarbons

International Nuclear Information System (INIS)

Woodbridge, D.D.

1979-01-01

This invention relates to a process for treating a fluid hydrocarbon fuel for retarding the agglomeration between particles thereof and for retarding the growth of bacteria and fungi therein. The process includes that steps of transporting a plurality of unit volumes of said fluid hydrocarbon fuel through an irradiating location and irradiating each unit of the plurality of unit volumes at the irradiating location with either neutron or gamma radiation. An apparatus for treating the fluid hydrocarbon fuels with the nuclear radiation also is provided. The apparatus includes a generally conical central irradiating cavity which is surrounded by a spiral outer irradiating cavity. The fluid hydrocarbon fuel is transported through the cavities while being irradiated by the nuclear radiation

Consequence of nanofluid on peristaltic transport of a hyperbolic tangent fluid model in the occurrence of apt (tending) magnetic field

International Nuclear Information System (INIS)

Akram, Safia; Nadeem, S.

2014-01-01

In the current study, sway of nanofluid on peristaltic transport of a hyperbolic tangent fluid model in the incidence of tending magnetic field has been argued. The governing equations of a nanofluid are first modeled and then simplified under lubrication approach. The coupled nonlinear equations of temperature and nano particle volume fraction are solved analytically using a homotopy perturbation technique. The analytical solution of the stream function and pressure gradient are carried out using perturbation technique. The graphical results of the problem under discussion are also being brought under consideration to see the behavior of various physical parameters. - Highlights: • The main motivation of this work is that we want to see the behavior of nanofluids in peristaltic flows. • In literature few articles are available on this, but no article is available in asymmetric channel on the new fluid model hyperbolic tangent fluid. • So we want to fill the gap in literature studying this

Consequence of nanofluid on peristaltic transport of a hyperbolic tangent fluid model in the occurrence of apt (tending) magnetic field

Energy Technology Data Exchange (ETDEWEB)

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

2014-05-01

In the current study, sway of nanofluid on peristaltic transport of a hyperbolic tangent fluid model in the incidence of tending magnetic field has been argued. The governing equations of a nanofluid are first modeled and then simplified under lubrication approach. The coupled nonlinear equations of temperature and nano particle volume fraction are solved analytically using a homotopy perturbation technique. The analytical solution of the stream function and pressure gradient are carried out using perturbation technique. The graphical results of the problem under discussion are also being brought under consideration to see the behavior of various physical parameters. - Highlights: • The main motivation of this work is that we want to see the behavior of nanofluids in peristaltic flows. • In literature few articles are available on this, but no article is available in asymmetric channel on the new fluid model hyperbolic tangent fluid. • So we want to fill the gap in literature studying this.

Effect of condensation temperature glide on the performance of organic Rankine cycles with zeotropic mixture working fluids

International Nuclear Information System (INIS)

Liu, Qiang; Duan, Yuanyuan; Yang, Zhen

2014-01-01

Highlights: • A condensation pressure determination method for ORC with zeotropic mixture is given. • The effects of condensation temperature glide on the ORC performance are analyzed. • Mixture mole fractions for the maximum power output of a geothermal ORC are identified. • The biomass ORC performance with part of the latent heat transferred in the IHE is analyzed. - Abstract: The organic Rankine cycle (ORC) has been widely used to convert low-grade ( 2 M) selected as working fluids for the cogenerative ORC driven by the biomass energy. Two optimal working fluid mole fractions maximize the cycle efficiency, exergy efficiency and net power output for cooling water temperature increases less than the maximum condensation temperature glide, while the highest net power output appears at the higher mole fraction of the more volatile component for the geothermal ORC when the condensation temperature glide of the working fluid mixture matches the cooling water temperature increase. Higher condensation temperature glides result in large thermal loss to the heat sink and exergy destruction in the condenser. There is only one optimal working fluid mole fraction that maximizes the thermal efficiency, exergy efficiency and net power output when the cooling water temperature increase is greater than the condensation temperature glide

Phase diagram and transport properties for hydrogen-helium fluid planets

International Nuclear Information System (INIS)

Stevenson, D.J.; Salpeter, E.E.

1977-01-01

Hydrogen and helium are the major constituents of Jupiter and Saturn, and phase transitions can have important effects on the planetary structure. In this paper, the relevant phase diagrams and microscopic transport properties are analyzed in detail. The following paper (Paper II) applies these results to the evolution and present dynamic structure of the Jovian planets.Pure hydrogen is first discussed, especially the nature of the molecular-metallic transition and the melting curves for the two phases. It is concluded that at the temperatures and pressures of interest (Tapprox. =10 4 K, Papprox. =1--10 Mbar), both phases are fluid, but the transition between them might nevertheless be first-order. The insulator-metal transition in helium occurs at a much higher pressure (approx.70 Mbars) and is not of interest.The phase diagrams for both molecular and metallic hydrogen-helium mixtures are discussed. In the metallic mixture, calculations indicate a miscibility gap for T9 or approx. =10 4 K. Immiscibility in the molecular mixture is more difficult to predict but almost certainly occurs at much lower temperatures. A fluid-state model is constructed which predicts the likely topology of the three-dimensional phase diagram. The greater solubility of helium in the molecular phase leads to the prediction that the He/H mass ratio is typically twice as large in the molecular phase as in the coexisting metallic phase. Under these circumstances a ''density inversion'' is possible in which the molecular phase becomes more dense than the metallic phase.The partitioning of minor constituents is also considered: The deuterium/hydrogen mass ratio is essentially the same for all coexisting hydrogen-helium phases, at least for T> or approx. =5000 K. The partitioning of H 2 O, CH 4 , and NH 3 probably favors the molecular (or helium-rich) phase. Substances with high conduction electron density (e.g., Al) may partition into the metallic phase

Insulin transport into the brain and cerebrospinal fluid.

Science.gov (United States)

Begg, Denovan P

2015-01-01

The pancreatic hormone insulin plays a well-described role in the periphery, based principally on its ability to lower circulating glucose levels via activation of glucose transporters. However, insulin also acts within the central nervous system (CNS) to alter a number of physiological outcomes ranging from energy balance and glucose homeostasis to cognitive performance. Insulin is transported into the CNS by a saturable receptor-mediated process that is proposed to be dependent on the insulin receptor. Transport of insulin into the brain is dependent on numerous factors including diet, glycemia, a diabetic state and notably, obesity. Obesity leads to a marked decrease in insulin transport from the periphery into the CNS and the biological basis of this reduction of transport remains unresolved. Despite decades of research into the effects of central insulin on a wide range of physiological functions and its transport from the periphery to the CNS, numerous questions remain unanswered including which receptor is responsible for transport and the precise mechanisms of action of insulin within the brain. © 2015 Elsevier Inc. All rights reserved.

Forced fluid removal in intensive care patients with acute kidney injury

DEFF Research Database (Denmark)

Berthelsen, R E; Perner, A; Jensen, A K

2018-01-01

/or continuous renal replacement therapy aiming at net negative fluid balance > 1 mL/kg ideal body weight/hour until cumulative fluid balance calculated from ICU admission reached less than 1000 mL. RESULTS: After 20 months, we stopped the trial prematurely due to a low inclusion rate with 23 (2%) included...... patients out of the 1144 screened. Despite the reduced sample size, we observed a marked reduction in cumulative fluid balance 5 days after randomisation (mean difference -5814 mL, 95% CI -2063 to -9565, P = .003) with forced fluid removal compared to standard care. While the trial was underpowered...... for clinical endpoints, no point estimates suggested harm from forced fluid removal. CONCLUSIONS: Forced fluid removal aiming at 1 mL/kg ideal body weight/hour may be an effective treatment of fluid accumulation in ICU patients with acute kidney injury. A definitive trial using our inclusion criteria seems...

Implant-assisted magnetic drug targeting in permeable microvessels: Comparison of two-fluid statistical transport model with experiment

Energy Technology Data Exchange (ETDEWEB)

ChiBin, Zhang; XiaoHui, Lin, E-mail: lxh60@seu.edu.cn; ZhaoMin, Wang; ChangBao, Wang

2017-03-15

In experiments and theoretical analyses, this study examines the capture efficiency (CE) of magnetic drug carrier particles (MDCPs) for implant-assisted magnetic drug targeting (IA-MDT) in microvessels. It also proposes a three-dimensional statistical transport model of MDCPs for IA-MDT in permeable microvessels, which describes blood flow by the two-fluid (Casson and Newtonian) model. The model accounts for the permeable effect of the microvessel wall and the coupling effect between the blood flow and tissue fluid flow. The MDCPs move randomly through the microvessel, and their transport state is described by the Boltzmann equation. The regulated changes and factors affecting the CE of the MDCPs in the assisted magnetic targeting were obtained by solving the theoretical model and by experimental testing. The CE was negatively correlated with the blood flow velocity, and positively correlated with the external magnetic field intensity and microvessel permeability. The predicted CEs of the MDCPs were consistent with the experimental results. Additionally, under the same external magnetic field, the predicted CE was 5–8% higher in the IA-MDT model than in the model ignoring the permeability effect of the microvessel wall. - Highlights: • A model of MDCPs for IA-MDT in permeable microvessels was established. • An experimental device was established, the CE of MDCPs was measured. • The predicted CE of MDCPs was 5–8% higher in the IA-MDT model.

High-order Two-Fluid Plasma Solver for Direct Numerical Simulations of Magnetic Flows with Realistic Transport Phenomena

Science.gov (United States)

Li, Zhaorui; Livescu, Daniel

2017-11-01

The two-fluid plasma equations with full transport terms, including temperature and magnetic field dependent ion and electron viscous stresses and heat fluxes, frictional drag force, and ohmic heating term have been solved by using the sixth-order non-dissipative compact scheme for plasma flows in several different regimes. In order to be able to fully resolve all the dynamically relevant time and length scales while maintaining computational feasibility, the assumptions of infinite speed of light and negligible electron inertia have been made. The accuracy and robustness of this two-fluid plasma solver in handling plasma flows have been tested against a series of canonical problems, such as Alfven-Whistler dispersion relation, electromagnetic plasma shock, magnetic reconnection, etc. For all test cases, grid convergence tests have been conducted to achieve fully resolved results. The roles of heat flux, viscosity, resistivity, Hall and Biermann battery effects, are investigated for the canonical flows studied.

Cerebrospinal and Interstitial Fluid Transport via the Glymphatic Pathway Modeled by Optimal Mass Transport

OpenAIRE

Ratner, Vadim; Gao, Yi; Lee, Hedok; Elkin, Rena; Nedergaard, Maiken; Benveniste, Helene; Tannenbaum, Allen

2017-01-01

The glymphatic pathway is a system which facilitates continuous cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange and plays a key role in removing waste products from the rodent brain. Dysfunction of the glymphatic pathway may be implicated in the pathophysiology of Alzheimer's disease. Intriguingly, the glymphatic system is most active during deep wave sleep general anesthesia. By using paramagnetic tracers administered into CSF of rodents, we previously showed the utility of M...

Communication: A method to compute the transport coefficient of pure fluids diffusing through planar interfaces from equilibrium molecular dynamics simulations.

Science.gov (United States)

Vermorel, Romain; Oulebsir, Fouad; Galliero, Guillaume

2017-09-14

The computation of diffusion coefficients in molecular systems ranks among the most useful applications of equilibrium molecular dynamics simulations. However, when dealing with the problem of fluid diffusion through vanishingly thin interfaces, classical techniques are not applicable. This is because the volume of space in which molecules diffuse is ill-defined. In such conditions, non-equilibrium techniques allow for the computation of transport coefficients per unit interface width, but their weak point lies in their inability to isolate the contribution of the different physical mechanisms prone to impact the flux of permeating molecules. In this work, we propose a simple and accurate method to compute the diffusional transport coefficient of a pure fluid through a planar interface from equilibrium molecular dynamics simulations, in the form of a diffusion coefficient per unit interface width. In order to demonstrate its validity and accuracy, we apply our method to the case study of a dilute gas diffusing through a smoothly repulsive single-layer porous solid. We believe this complementary technique can benefit to the interpretation of the results obtained on single-layer membranes by means of complex non-equilibrium methods.

Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1987-01-01

The author describes a Petri net model, called coloured Petri nets (CP-nets), by means of which it is possible to describe large systems without having to cope with unnecessary details. The author introduces CP-nets and provide a first impression of their modeling power and the suitability...

Net one, net two: the primary care network income statement.

Science.gov (United States)

Halley, M D; Little, A W

1999-10-01

Although hospital-owned primary care practices have been unprofitable for most hospitals, some hospitals are achieving competitive advantage and sustainable practice operations. A key to the success of some has been a net income reporting tool that separates practice operating expenses from the costs of creating and operating a network of practices to help healthcare organization managers, physicians, and staff to identify opportunities to improve the network's financial performance. This "Net One, Net Two" reporting allows operations leadership to be held accountable for Net One expenses and strategic leadership to be held accountable for Net Two expenses.

Remote assessment of net shore drift along the west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Kunte, P.D.; Wagle, B.G.; Sugimori, Y.

-directional, net major sediment transport is southward. The geomorphic study identified possible sediment sources and sinks. Contributions of sources and losses due to sinks are assessed. The sediment balance is positive overall, and is reflected in large spits...

Slip analysis of squeezing flow using doubly stratified fluid

Science.gov (United States)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-06-01

The non-isothermal flow is modeled and explored for squeezed fluid. The influence of velocity, thermal and solutal slip effects on transport features of squeezed fluid are analyzed through Darcy porous channel when fluid is moving due to squeezing of upper plate towards the stretchable lower plate. Dual stratification effects are illustrated in transport equations. A similarity analysis is performed and reduced governing flow equations are solved using moderated and an efficient convergent approach i.e. Homotopic technique. The significant effects of physical emerging parameters on flow velocity, temperature and fluid concentration are reporting through various plots. Graphical explanations for drag force, Nusselt and Sherwood numbers are stated and examined. The results reveal that minimum velocity field occurs near the plate, whereas it increases far away from the plate for strong velocity slip parameter. Furthermore, temperature and fluid concentration significantly decreases with increased slip effects. The current analysis is applicable in some advanced technological processes and industrial fluid mechanics.

Homogenization of the internal structures of a reactor with the cooling fluid

Energy Technology Data Exchange (ETDEWEB)

Robbe, M.F. [CEA Saclay, SEMT, 91 - Gif sur Yvette (France); Bliard, F. [Socotec Industrie, Service AME, 78 - Montigny le Bretonneux (France)

2001-07-01

To take into account the influence of a structure net among a fluid flow, without modelling exactly the structure shape, a concept of ''equivalent porosity method'' was developed. The structures are considered as solid pores inside the fluid. The structure presence is represented by three parameters: a porosity, a shape coefficient and a pressure loss coefficient. The method was studied for an Hypothetical Core Disruptive Accident in a Liquid Metal Fast Breeder Reactor, but it can be applied to any problem involving fluid flow getting through a solid net. The model was implemented in the computer code CASTEM-PLEXUS and validated on an analytical shock tube test, simulating an horizontal slice of a schematic LMFBR in case of a HCDA (bubble at high pressure, liquid sodium and internal structures of the reactor). A short parametric study shows the influence of the porosity and the structure shape on the pressure wave impacting the shock tube bottom. These results were used to simulate numerically the HCDA mechanical effects in a small scale reactor mock-up. (author)

Homogenization of the internal structures of a reactor with the cooling fluid

International Nuclear Information System (INIS)

Robbe, M.F.; Bliard, F.

2001-01-01

To take into account the influence of a structure net among a fluid flow, without modelling exactly the structure shape, a concept of ''equivalent porosity method'' was developed. The structures are considered as solid pores inside the fluid. The structure presence is represented by three parameters: a porosity, a shape coefficient and a pressure loss coefficient. The method was studied for an Hypothetical Core Disruptive Accident in a Liquid Metal Fast Breeder Reactor, but it can be applied to any problem involving fluid flow getting through a solid net. The model was implemented in the computer code CASTEM-PLEXUS and validated on an analytical shock tube test, simulating an horizontal slice of a schematic LMFBR in case of a HCDA (bubble at high pressure, liquid sodium and internal structures of the reactor). A short parametric study shows the influence of the porosity and the structure shape on the pressure wave impacting the shock tube bottom. These results were used to simulate numerically the HCDA mechanical effects in a small scale reactor mock-up. (author)

Approach to uncertainty assessment for fluid flow and contaminant transport modeling in heterogeneous groundwater systems

International Nuclear Information System (INIS)

Nelson, R.W.; Jacobson, E.A.; Conbere, W.

1985-06-01

There is a growing awareness of the need to quantify uncertainty in groundwater flow and transport model results. Regulatory organizations are beginning to request the statistical distributions of predicted contaminant arrival to the biosphere, so that realistic confidence intervals can be obtained for the modeling results. To meet these needs, methods are being developed to quantify uncertainty in the subsurface flow and transport analysis sequence. A method for evaluating this uncertainty, described in this paper, considers uncertainty in material properties and was applied to an example field problem. Our analysis begins by using field measurements of transmissivity and hydraulic head in a regional, parameter estimation method to obtain a calibrated fluid flow model and a covariance matrix of the parameter estimation errors. The calibrated model and the covariance matrix are next used in a conditional simulation mode to generate a large number of 'head realizations.' The specific pore water velocity distribution for each realization is calculated from the effective porosity, the aquifer parameter realization, and the associated head values. Each velocity distribution is used to obtain a transport solution for a contaminant originating from the same source for all realizations. The results are the statistical distributions for the outflow arrival times. The confidence intervals for contamination reaching the biosphere are obtained from the outflow statistical distributions. 20 refs., 12 figs

Asymptotic limits of a statistical transport description

International Nuclear Information System (INIS)

Malvagi, F.; Levermore, C.D.; Pomraning, G.C.; Department of Mathematics, University of Arizona, Tucson, AZ 85721)

1989-01-01

We consider three different asymptotic limits of a model describing linear particle transport in a stochastic medium consisting of two randomly mixed immiscible fluids. These three limits are: (1) the fluid packets are small compared to the particle mean free path in the packet; (2) a small amount of large cross section fluid is admixed with a large amount of small cross section fluid; and (3) the angular dependence of the intensity (angular flux) is nearly isotropic. The first two limits reduce the underlying model, which consists of two coupled transport equations, to a single transport equation of the usual form. The third limit yields a two-equation diffusion approximation, and a boundary layer analysis gives boundary conditions for these two coupled diffusion equations

Solution of hydraulic nets, by means of the application of the pattern of balance of nodes and the method of linealization of equations

International Nuclear Information System (INIS)

Narvaez Rincon, Paulo Cesar; Granados Jorge Armando, Barrera Hector

1999-01-01

The dimension of nets of fluids distribution is a common problem to different areas of the engineering, as the chemistry and the civil, present in the design of aqueducts, distribution systems of domiciliary gas, nets against fire and plants of chemical transformation. This work presents a model for its simulation, by means of the application of the balance of nodes and the theory of linealization of equations, it allows to know a complex net, in which they can be present, accessories, bombs, control valves, aspersion mouthpieces and process equipment. It is applicable to open, closed nets or combinations of two

Fluid-driven metamorphism of the continental crust governed by nanoscale fluid flow

NARCIS (Netherlands)

Plümper, O.; Botan, Alexandru; Los, Catharina; Liu, Yang; Malthe-Sorenssen, Anders; Jamtveit, Bjørn

2017-01-01

The transport of fluids through the Earth’s crust controls the redistribution of elements to form mineral and hydrocarbon deposits, the release and sequestration of greenhouse gases, and facilitates metamorphic reactions that influence lithospheric rheology. In permeable systems with a

Fluid Dynamics And Mass Transfer In Two-Fluid Taylor-Couette Flow

International Nuclear Information System (INIS)

Baier, G.; Graham, M.D.

1998-01-01

The Taylor-Couette instability of a single liquid phase can be used to enhance mass transfer processes such as filtration and membrane separations. We consider here the possibility of using this instability to enhance interphase transport in a two-fluid systems, with a view toward improved liquid-liquid extractions for biotechnology applications. We investigate the centrifugal instability of a pair of radially stratified immiscible liquids in the annular gap between concentric, corotating cylinders: two-fluid Taylor-Couette flow. Experiments show that a two-layer flow with a well-defined interface and Taylor vortices in each phase can be obtained. The experimental results are in good agreement with predictions of inviscid arguments based on a two-phase extension of Rayleigh's criterion, as well as with detailed linear stability calculations. For a given geometry, the most stable configuration occurs for fluids of roughly (exactly in the inviscid limit) equal dynamic viscosities. A number of preliminary mass transfer experiments have also been performed, in the presence of axial counterflow. The onset of Taylor vortices coincides with a clear decrease in the extent of axial dispersion and an increase in the rate of interphase transport, thus suggesting that this flow geometry may provide an effective means for countercurrent chromatographic separations

Proceedings of the sixth international and forty third national conference on fluid mechanics and fluid power: book of abstracts

International Nuclear Information System (INIS)

Jain, Anuj; Paul, Akshoy Ranjan

2016-01-01

Fluid Mechanics and Fluid Power (FMFP) Conference is an important meeting to promote all activities in the field of Fluid Mechanics and Fluid Power in India. FMFP-2016 offers great opportunity to scientists, researchers, engineers and business executives from all parts of the world to share the recent advancements and future trends in all aspects of fluid mechanics and fluid power- be it theoretical, experimental, applied and computational, and build network. It covers theoretical and experimental fluid dynamics, flow instability, transition, turbulence and control, fluid machinery, turbomachinery and fluid power, IC engines and gas turbines, multiphase flows, fluid-structure interaction and flow-induced noise, micro and nano fluid mechanics, bio-inspired fluid mechanics, energy and environment, specialized topics (transport phenomena in materials processing and manufacturing, MHD and EHD flows, granular flows, nuclear reactor, thermal hydraulics, defence and space engineering, sustainable habitat. Papers relevant to INIS are indexed separately

VitisNet: "Omics" integration through grapevine molecular networks.

Directory of Open Access Journals (Sweden)

Jérôme Grimplet

Full Text Available BACKGROUND: Genomic data release for the grapevine has increased exponentially in the last five years. The Vitis vinifera genome has been sequenced and Vitis EST, transcriptomic, proteomic, and metabolomic tools and data sets continue to be developed. The next critical challenge is to provide biological meaning to this tremendous amount of data by annotating genes and integrating them within their biological context. We have developed and validated a system of Grapevine Molecular Networks (VitisNet. METHODOLOGY/PRINCIPAL FINDINGS: The sequences from the Vitis vinifera (cv. Pinot Noir PN40024 genome sequencing project and ESTs from the Vitis genus have been paired and the 39,424 resulting unique sequences have been manually annotated. Among these, 13,145 genes have been assigned to 219 networks. The pathway sets include 88 "Metabolic", 15 "Genetic Information Processing", 12 "Environmental Information Processing", 3 "Cellular Processes", 21 "Transport", and 80 "Transcription Factors". The quantitative data is loaded onto molecular networks, allowing the simultaneous visualization of changes in the transcriptome, proteome, and metabolome for a given experiment. CONCLUSIONS/SIGNIFICANCE: VitisNet uses manually annotated networks in SBML or XML format, enabling the integration of large datasets, streamlining biological functional processing, and improving the understanding of dynamic processes in systems biology experiments. VitisNet is grounded in the Vitis vinifera genome (currently at 8x coverage and can be readily updated with subsequent updates of the genome or biochemical discoveries. The molecular network files can be dynamically searched by pathway name or individual genes, proteins, or metabolites through the MetNet Pathway database and web-portal at http://metnet3.vrac.iastate.edu/. All VitisNet files including the manual annotation of the grape genome encompassing pathway names, individual genes, their genome identifier, and chromosome

Computational transport phenomena for engineering analyses

CERN Document Server

Farmer, Richard C; Cheng, Gary C; Chen, Yen-Sen

2009-01-01

Computational Transport PhenomenaOverviewTransport PhenomenaAnalyzing Transport PhenomenaA Computational Tool: The CTP CodeVerification, Validation, and GeneralizationSummaryNomenclatureReferencesThe Equations of ChangeIntroductionDerivation of The Continuity EquationDerivation of The Species Continuity EquationDerivation of The Equation Of MotionDerivation of The General Energy EquationNon-Newtonian FluidsGeneral Property BalanceAnalytical and Approximate Solutions for the Equations of ChangeSummaryNomenclatureReferencesPhysical PropertiesOverviewReal-Fluid ThermodynamicsChemical Equilibrium

Supercritical fluids technology. Pt. 1 General topics

International Nuclear Information System (INIS)

Marongiu, B.; De Giorgi, M. R.; Porcedda, S.; Cadoni, E.

1998-01-01

Supercritical fluids technology is among the emerging 'clean' technologies, that allows the minimization in the use of chemical and thermic treatments and products irradiation, diminishing the quantity of liquid wastes to be treated. In this first article phase equilibria thermodynamics and fluid mechanics of transport phenomena are reviewed [it

Comparison of lactate and bicarbonate buffered haemofiltration fluids: use in critically ill patients.

Science.gov (United States)

Thomas, A N; Guy, J M; Kishen, R; Geraghty, I F; Bowles, B J; Vadgama, P

1997-06-01

To compare acid-base balance, lactate concentration, and haemodynamic and O2 transport variables during haemofiltration with replacement fluid containing 44.5 mmol/l Na+ lactate or 40 mmol/l Na+ HCO3- and 3 mmol/l lactic acid. A prospective, randomized trial. A multidisciplinary, adult intensive care unit in a university hospital. Forty acidotic patients who required haemofiltration, were dependent on mechanical ventilation, and had PA catheters in situ. During haemofiltration patients received lactate or bicarbonate replacement fluid at a mean rate of 1.7 l/h (SD 0.3). Arterial blood gases, plasma lactate, and haemodynamic and O2 transport variables were measured before and after 12 and 24 h haemofiltration. Ultrafiltrate was collected for lactate estimation. As means (SD). The net gain of lactate was 63 mmol/h (12 mmol) with Na+ lactate and 0 mmol/h (0.3 mmol) with Na+ HCO3-. There was a significant increase in pH and [lactate] in both groups, but [lactate] was higher in patients receiving lactate. Twenty-one patients survived to ICU discharge, these patients were significantly less acidotic after filtration (lactate group: 0 h: pH 7.23 (0.09), [lactate] 2.4 mmol/l (1.7); 12 h: pH 7.34 (0.09), [lactate] 4.7 mmol/l (2.4); 24 h: pH 7.36 (0.07), [lactate] 4.7 mmol (2.7). HCO3 group: 0 h: pH 7.23 (0.09), [lactate] 2.3 (1.3); 12 h: pH 7.32 (0.06), [lactate] 2.9 mmol/l (1.8); 24 h: pH 7.35 (0.08), [lactate] 2.8 mmol/l (2.0). Base deficit: survivors: 0 h: 9 mmol/l (4); 12 h: 2 mmol/l (3). Non-survivors: 0 h: 10 mmol/l (3); 12 h: 6 mmol/l (3)). Haemodynamic and O2 transport variables were not significantly affected by treatment group or outcome. The degree of correction of acidosis during the first 24 h of haemofiltration was determined by patients outcome but was not affected by the substitution of bicarbonate- for lactate-containing replacement fluids.

Thermophysical properties of supercritical fluids and fluid mixtures

International Nuclear Information System (INIS)

Sengers, J.V.

1991-07-01

This research is concerned with the development of a quantitative scientific description of the thermodynamic and transport properties of supercritical and subcritical fluids and fluid mixtures. It is known that the thermophysical properties of fluids and fluid mixtures asymptotically close to the critical point satisfy scaling laws with universal critical exponents and universal scaling functions. However, the range of validity of these asymptotic scaling laws is quite small. As a consequence, the impact of the modern theory of critical phenomena on chemical engineering has been limited. On the other hand, an a priori estimate of the range of temperatures and densities, where critical fluctuations become significant, can be made on the basis of the so-called Ginzburg criterion. A recent analysis of this criterion suggests that this range is actually quite large and for a fluid like carbon dioxide can easily extend to 100 degrees or so above the critical temperature. Hence, the use of traditional engineering equations like cubic equations is not scientifically justified in a very wide range of temperatures and densities around the critical point. We have therefore embarked on a scientific approach to deal with the global effects of critical fluctuations on the thermophysical properties of fluids and fluid mixtures. For this purpose it is not sufficient to consider the asymptotic critical fluctuations but we need to deal also with the nonasymptotic critical fluctuations. The goal is to develop scientifically based questions that account for the crossover of the thermophysical properties from their asymptotic singular behavior in the near vicinity of the critical point to their regular behavior very far away from the critical point

Mass transfer in nano-fluids: A review

International Nuclear Information System (INIS)

Ashrafmansouri, Seyedeh-Saba; Esfahany, Mohsen Nasr

2014-01-01

Growing attention has been recently paid to nano-fluids because of their potential for augmenting transfer processes - i.e., heat and mass transfer. Conflicting results have been reported in the literature on mass transfer in nano-fluids. The aim of this paper is to summarize the literature on mass transfer in nano-fluids stating the conflicts and possible reasons. Literature on mass transfer in nano-fluids has been reviewed in two sections. The first section concentrates on surveying mass diffusivity in nano-fluids while the second section focuses on convective mass transfer in nano-fluids. In each section, published articles, type of nano-fluids used, size and concentration range of nanoparticles, measurement methods, maximum observed enhancement, and suggested mass transport mechanisms are summarized. (authors)

Collection of apoplastic fluids from Arabidopsis thaliana leaves

DEFF Research Database (Denmark)

Madsen, Svend Roesen; Nour-Eldin, Hussam Hassan; Halkier, Barbara Ann

2016-01-01

The leaf apoplast comprises the extracellular continuum outside cell membranes. A broad range of processes take place in the apoplast, including intercellular signaling, metabolite transport, and plant-microbe interactions. To study these processes, it is essential to analyze the metabolite conte...... in apoplastic fluids. Due to the fragile nature of leaf tissues, it is a challenge to obtain apoplastic fluids from leaves. Here, methods to collect apoplastic washing fluid and guttation fluid from Arabidopsis thaliana leaves are described....

Antenatal Corticosteroids and Postnatal Fluid Restriction Produce Differential Effects on AQP3 Expression, Water Handling, and Barrier Function in Perinatal Rat Epidermis

Directory of Open Access Journals (Sweden)

Johan Agren

2010-01-01

Full Text Available Loss of water through the immature skin can lead to hypothermia and dehydration in preterm infants. The water and glycerol channel aquaglyceroporin-3 (AQP3 is abundant in fetal epidermis and might influence epidermal water handling and transepidermal water flux around birth. To investigate the role of AQP3 in immature skin, we measured in vivo transepidermal water transport and AQP3 expression in rat pups exposed to clinically relevant fluid homeostasis perturbations. Preterm (E18 rat pups were studied after antenatal corticosteroid exposure (ANS, and neonatal (P1 rat pups after an 18 h fast. Transepidermal water loss (TEWL and skin hydration were determined, AQP3 mRNA was quantified by RT-PCR, and in-situ hybridization and immunocytochemistry were applied to map AQP3 expression. ANS resulted in an improved skin barrier (lower TEWL and skin hydration, while AQP3 mRNA and protein increased. Fasting led to loss of barrier integrity along with an increase in skin hydration. These alterations were not paralleled by any changes in AQP3. To conclude, antenatal corticosteroids and early postnatal fluid restriction produce differential effects on skin barrier function and epidermal AQP3 expression in the rat. In perinatal rats, AQP3 does not directly determine net water transport through the skin.

TRANSPORT CHARACTERISTICS OF SELECTED PWR LOCA GENERATED DEBRIS

International Nuclear Information System (INIS)

MAJI, A. K.; MARSHALL, B.

2000-01-01

In the unlikely event of a Loss of Coolant Accident (LOCA) in a pressurized water reactor (PWR), break jet impingement would dislodge thermal insulation FR-om nearby piping, as well as other materials within the containment, such as paint chips, concrete dust, and fire barrier materials. Steam/water flows induced by the break and by the containment sprays would transport debris to the containment floor. Subsequently, debris would likely transport to and accumulate on the suction sump screens of the emergency core cooling system (ECCS) pumps, thereby potentially degrading ECCS performance and possibly even failing the ECCS. In 1998, the U. S. Nuclear Regulatory Commission (NRC) initiated a generic study (Generic Safety Issue-191) to evaluate the potential for the accumulation of LOCA related debris on the PWR sump screen and the consequent loss of ECCS pump net positive suction head (NPSH). Los Alamos National Laboratory (LANL), supporting the resolution of GSI-191, was tasked with developing a method for estimating debris transport in PWR containments to estimate the quantity of debris that would accumulate on the sump screen for use in plant specific evaluations. The analytical method proposed by LANL, to predict debris transport within the water that would accumulate on the containment floor, is to use computational fluid dynamics (CFD) combined with experimental debris transport data to predict debris transport and accumulation on the screen. CFD simulations of actual plant containment designs would provide flow data for a postulated accident in that plant, e.g., three-dimensional patterns of flow velocities and flow turbulence. Small-scale experiments would determine parameters defining the debris transport characteristics for each type of debris. The containment floor transport methodology will merge debris transport characteristics with CFD results to provide a reasonable and conservative estimate of debris transport within the containment floor pool and

Geothermal energy production with supercritical fluids

Science.gov (United States)

Brown, Donald W.

2003-12-30

There has been invented a method for producing geothermal energy using supercritical fluids for creation of the underground reservoir, production of the geothermal energy, and for heat transport. Underground reservoirs are created by pumping a supercritical fluid such as carbon dioxide into a formation to fracture the rock. Once the reservoir is formed, the same supercritical fluid is allowed to heat up and expand, then is pumped out of the reservoir to transfer the heat to a surface power generating plant or other application.

Performance analysis of organic Rankine cycles using different working fluids

Directory of Open Access Journals (Sweden)

Zhu Qidi

2015-01-01

Full Text Available Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC’s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo

2015-09-15

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.

Predictions of the near edge transport shortfall in DIII-D L-mode plasmas using the trapped gyro-Landau-fluid model

Energy Technology Data Exchange (ETDEWEB)

Kinsey, J. E. [CompX, P.O. Box 2672, Del Mar, California 92014 (United States); Staebler, G. M.; Candy, J.; Petty, C. C.; Waltz, R. E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Rhodes, T. L. [Physics Department and PSTI, University of California, Los Angeles, California 90095 (United States)

2015-01-15

Previous studies of DIII-D L-mode plasmas have shown that a transport shortfall exists in that our current models of turbulent transport can significantly underestimate the energy transport in the near edge region. In this paper, the Trapped Gyro-Landau-Fluid (TGLF) drift wave transport model is used to simulate the near edge transport in a DIII-D L-mode experiment designed to explore the impact of varying the safety factor on the shortfall. We find that the shortfall systematically increases with increasing safety factor and is more pronounced for the electrons than for the ions. Within the shortfall dataset, a single high current case has been found where no transport shortfall is predicted. Reduced neutral beam injection power has been identified as the key parameter separating this discharge from other discharges exhibiting a shortfall. Further analysis shows that the energy transport in the L-mode near edge region is not stiff according to TGLF. Unlike the H-mode core region, the predicted temperature profiles are relatively more responsive to changes in auxiliary heating power. In testing the fidelity of TGLF for the near edge region, we find that a recalibration of the collision model is warranted. A recalibration improves agreement between TGLF and nonlinear gyrokinetic simulations performed using the GYRO code with electron-ion collisions. The recalibration only slightly impacts the predicted shortfall.

Dynamics of albumin in plasma and ascitic fluid in patients with cirrhosis

DEFF Research Database (Denmark)

Henriksen, Jens Henrik; Siemssen, O; Krintel, J J

2001-01-01

BACKGROUND/AIMS: To determine dynamics of albumin in plasma and ascitic fluid of patients with cirrhosis. METHODS: Forty-seven patients were classified in four groups: I--patients without fluid retention; II--patients with ascites not resistant to subsequent diuretic treatment; III......--recompensated patients during diuretic treatment; and IV--patients with diuretic-resistant ascites. Transvascular and transperitoneal albumin transports were quantified by 131I-/125I-labelled human albumin. RESULTS: TER(P) (i.e. the fraction of intravascular albumin (IVM) passing from plasma into the interstitial space...... per hour) was increased in all groups. In group IV patients the transport rate of albumin from plasma into the ascitic fluid (TER(PA)) was significantly higher than the transport rate from the ascitic fluid back into the plasma: TER(AP) (0.45 vs. 0.26% IVM/h, P

Reserpine-induced reduction in norepinephrine transporter function requires catecholamine storage vesicles.

Science.gov (United States)

Mandela, Prashant; Chandley, Michelle; Xu, Yao-Yu; Zhu, Meng-Yang; Ordway, Gregory A

2010-01-01

Treatment of rats with reserpine, an inhibitor of the vesicular monoamine transporter (VMAT), depletes norepinephrine (NE) and regulates NE transporter (NET) expression. The present study examined the molecular mechanisms involved in regulation of the NET by reserpine using cultured cells. Exposure of rat PC12 cells to reserpine for a period as short as 5min decreased [(3)H]NE uptake capacity, an effect characterized by a robust decrease in the V(max) of the transport of [(3)H]NE. As expected, reserpine did not displace the binding of [(3)H]nisoxetine from the NET in membrane homogenates. The potency of reserpine for reducing [(3)H]NE uptake was dramatically lower in SK-N-SH cells that have reduced storage capacity for catecholamines. Reserpine had no effect on [(3)H]NE uptake in HEK-293 cells transfected with the rat NET (293-hNET), cells that lack catecholamine storage vesicles. NET regulation by reserpine was independent of trafficking of the NET from the cell surface. Pre-exposure of cells to inhibitors of several intracellular signaling cascades known to regulate the NET, including Ca(2+)/Ca(2+)-calmodulin dependent kinase and protein kinases A, C and G, did not affect the ability of reserpine to reduce [(3)H]NE uptake. Treatment of PC12 cells with the catecholamine depleting agent, alpha-methyl-p-tyrosine, increased [(3)H]NE uptake and eliminated the inhibitory effects of reserpine on [(3)H]NE uptake. Reserpine non-competitively inhibits NET activity through a Ca(2+)-independent process that requires catecholamine storage vesicles, revealing a novel pharmacological method to modify NET function. Further characterization of the molecular nature of reserpine's action could lead to the development of alternative therapeutic strategies for treating disorders known to be benefitted by treatment with traditional competitive NET inhibitors. Copyright 2010 Elsevier Ltd. All rights reserved.

Asymmetric continuum extreme processes in solids and fluids

CERN Document Server

Teisseyre, Roman

2014-01-01

This book deals with a class of basic deformations in asymmetric continuum theory. It describes molecular deformations and transport velocities in fluids, strain deformations in solids as well as the molecular transport, important in fracture processes.

[SOPHO-NET - a research network on psychotherapy for social phobia].

Science.gov (United States)

Leichsenring, Falk; Salzer, Simone; Beutel, Manfred E; von Consbruch, Katrin; Herpertz, Stephan; Hiller, Wolfgang; Hoyer, Jürgen; Hüsing, Johannes; Irle, Eva; Joraschky, Peter; Konnopka, Alexander; König, Hans-Helmut; de Liz, Therese; Nolting, Björn; Pöhlmann, Karin; Ruhleder, Mirjana; Schauenburg, Henning; Stangier, Ulrich; Strauss, Bernhard; Subic-Wrana, Claudia; Vormfelde, Stefan V; Weniger, Godehard; Willutzki, Ulrike; Wiltink, Jörg; Leibing, Eric

2009-01-01

This paper presents the Social Phobia Psychotherapy Research Network (SOPHO-NET). SOPHO-NET is among the five research networks on psychotherapy funded by "Bundesministerium für Bildung und Forschung". The research program encompasses a coordinated group of studies of social phobia. In the central project (Study A), a multi-center randomized controlled trial, refined models of manualized cognitive-behavioral therapy (CBT) and manualized short-term psychodynamic psychotherapy (STPP) are compared in the treatment of social phobia. A sample of n=512 outpatients will be randomized to either CBT, STPP or wait list. For quality assurance and treatment integrity, a specific project has been established (Project Q). Study A is complemented by four interrelated projects focusing on attachment style (Study B1), cost-effectiveness (Study B2), polymorphisms in the serotonin transporter gene (Study C1) and on structural and functional deviations of hippocampus and amygdala (Study C2). Thus, the SOPHO-NET program allows for a highly interdisciplinary research of psychotherapy in social phobia.

Reserpine-induced Reduction in Norepinephrine Transporter Function Requires Catecholamine Storage Vesicles

OpenAIRE

Mandela, Prashant; Chandley, Michelle; Xu, Yao-Yu; Zhu, Meng-Yang; Ordway, Gregory A.

2010-01-01

Treatment of rats with reserpine, an inhibitor of the vesicular monoamine transporter (VMAT), depletes norepinephrine (NE) and regulates NE transporter (NET) expression. The present study examined the molecular mechanisms involved in regulation of the NET by reserpine using cultured cells. Exposure of rat PC12 cells to reserpine for a period as short as 5 min decreased [3H]NE uptake capacity, an effect characterized by a robust decrease in the Vmax of the transport of [3H]NE. As expected, res...

Global net primary production and heterotrophic respiration for 1987

Energy Technology Data Exchange (ETDEWEB)

Hunt, R.E. Jr.; Piper, S.C.; Nemani, R. [Univ. of Montana, Missoula, MT (United States)]|[Scripps Institute of Oceanography, La Jolla, CA (United States)] [and others

1995-06-01

An ecosystem process model, BIOME-BGC, was parameterized and used to simulate the actual net primary production and heterotrophic respiration using daily climatic data, land cover type, leaf area index gridded to 1{degree} latitude by 1{degree} longitude grid cells for the year 1987. Global net primary production was 52 Pg C. These estimates were validated directly by two different methods. First, the grid cells were aggregated and used as inputs to a 3D atmospheric transport model, to compare CO{sub 2} station data with predictions. We simulated the intra-annual variation of atmospheric CO{sub 2} well for the northern hemisphere, but not for the southern hemisphere. Second, we calculated the net {sup 13}C uptake of vegetation, which is a function of water use efficiency. The {sup 13}C/{sup 12}C ratios agreed with measured data, indicating a strong limitation of global primary processes by the hydrologic cycle, especially precipitation. These are different from other global carbon models as we can simulate the year-to-year variation of climate, including El Nino, on the global carbon cycle.

Effects of fluid instabilities on laser fusion pellets

International Nuclear Information System (INIS)

Mead, W.C.; Lindl, J.D.

1975-01-01

A direct two-dimensional simulation method for fluid flow and plasma physics was used. The computer code LASNEX models the plasma phenomena of laser light absorption by inverse bremsstrahlung and plasma instabilities; energy transport and partition, using flux-limited diffusion and separate ion, electron, and radiation temperatures; and, optionally, effects of multigroup photon and particle transport and magnetic field physics. The fluid dynamics itself is Lagrangian, with an equation of state used to determine pressure, energy, and opacity as a function of density and temperature. Thermonuclear burn of compressed matter is included to permit evaluation of output to input energy ratios. The code tests with anomalies are described. Current understanding of fluid instability in the presence of ablation is discussed. (U.S.)

NaNet: a configurable NIC bridging the gap between HPC and real-time HEP GPU computing

International Nuclear Information System (INIS)

Lonardo, A.; Ameli, F.; Biagioni, A.; Frezza, O.; Cicero, F. Lo; Martinelli, M.; Paolucci, P.S.; Pastorelli, E.; Simeone, F.; Simula, F.; Tosoratto, L.; Vicini, P.; Ammendola, R.; Ramusino, A. Cotta; Fiorini, M.; Neri, I.; Lamanna, G.; Pontisso, L.; Sozzi, M.; Rossetti, D.

2015-01-01

NaNet is a FPGA-based PCIe Network Interface Card (NIC) design with GPUDirect and Remote Direct Memory Access (RDMA) capabilities featuring a configurable and extensible set of network channels. The design currently supports both standard—Gbe (1000BASE-T) and 10GbE (10Base-R)—and custom—34 Gbps APElink and 2.5 Gbps deterministic latency KM3link—channels, but its modularity allows for straightforward inclusion of other link technologies. The GPUDirect feature combined with a transport layer offload module and a data stream processing stage makes NaNet a low-latency NIC suitable for real-time GPU processing. In this paper we describe the NaNet architecture and its performances, exhibiting two of its use cases: the GPU-based low-level trigger for the RICH detector in the NA62 experiment at CERN and the on-/off-shore data transport system for the KM3NeT-IT underwater neutrino telescope

Application of deconvolution interferometry with both Hi-net and KiK-net data

Science.gov (United States)

Nakata, N.

2013-12-01

Application of deconvolution interferometry to wavefields observed by KiK-net, a strong-motion recording network in Japan, is useful for estimating wave velocities and S-wave splitting in the near surface. Using this technique, for example, Nakata and Snieder (2011, 2012) found changed in velocities caused by Tohoku-Oki earthquake in Japan. At the location of the borehole accelerometer of each KiK-net station, a velocity sensor is also installed as a part of a high-sensitivity seismograph network (Hi-net). I present a technique that uses both Hi-net and KiK-net records for computing deconvolution interferometry. The deconvolved waveform obtained from the combination of Hi-net and KiK-net data is similar to the waveform computed from KiK-net data only, which indicates that one can use Hi-net wavefields for deconvolution interferometry. Because Hi-net records have a high signal-to-noise ratio (S/N) and high dynamic resolution, the S/N and the quality of amplitude and phase of deconvolved waveforms can be improved with Hi-net data. These advantages are especially important for short-time moving-window seismic interferometry and deconvolution interferometry using later coda waves.

Transport Phenomenon in a Third-Grade Fluid Over an Oscillating Surface

Science.gov (United States)

Ali, A.; Saba, S.; Asghar, S.; Khan, D. N.

2017-11-01

The heat and mass transfer effects on the flow of a conducting third-grade fluid over an oscillating vertical porous plate with chemical reactions are considered. Highly nonlinear governing equations of the third-grade fluid are solved analytically by using a multi-parameter perturbation technique and compared with the numerical results obtained by the parallel shooting method. The fluid flow velocity, temperature, and concentration are analyzed as functions of the Hartmann number, suction parameter, Prandtl and Schmidt numbers, and chemical reaction parameter.

Transport characteristics of guanidino compounds at the blood-brain barrier and blood-cerebrospinal fluid barrier: relevance to neural disorders

Directory of Open Access Journals (Sweden)

Tachikawa Masanori

2011-02-01

Full Text Available Abstract Guanidino compounds (GCs, such as creatine, phosphocreatine, guanidinoacetic acid, creatinine, methylguanidine, guanidinosuccinic acid, γ-guanidinobutyric acid, β-guanidinopropionic acid, guanidinoethane sulfonic acid and α-guanidinoglutaric acid, are present in the mammalian brain. Although creatine and phosphocreatine play important roles in energy homeostasis in the brain, accumulation of GCs may induce epileptic discharges and convulsions. This review focuses on how physiologically important and/or neurotoxic GCs are distributed in the brain under physiological and pathological conditions. Transporters for GCs at the blood-brain barrier (BBB and the blood-cerebrospinal fluid (CSF barrier (BCSFB have emerged as substantial contributors to GCs distribution in the brain. Creatine transporter (CRT/solute carrier (SLC 6A8 expressed at the BBB regulates creatine concentration in the brain, and represents a major pathway for supply of creatine from the circulating blood to the brain. CRT may be a key factor facilitating blood-to-brain guanidinoacetate transport in patients deficient in S-adenosylmethionine:guanidinoacetate N-methyltransferase, the creatine biosynthetic enzyme, resulting in cerebral accumulation of guanidinoacetate. CRT, taurine transporter (TauT/SLC6A6 and organic cation transporter (OCT3/SLC22A3 expressed at the BCSFB are involved in guanidinoacetic acid or creatinine efflux transport from CSF. Interestingly, BBB efflux transport of GCs, including guanidinoacetate and creatinine, is negligible, though the BBB has a variety of efflux transport systems for synthetic precursors of GCs, such as amino acids and neurotransmitters. Instead, the BCSFB functions as a major cerebral clearance system for GCs. In conclusion, transport of GCs at the BBB and BCSFB appears to be the key determinant of the cerebral levels of GCs, and changes in the transport characteristics may cause the abnormal distribution of GCs in the brain seen

Fluid structure interaction in piston diaphragm pumps

NARCIS (Netherlands)

Van Rijswick, R.; Van Rhee, C.

2013-01-01

Piston diaphragm pumps are used world-wide for the transport of aggressive and/or abrasive fluids in the chemical, mining and mineral processing industries. Figure 1 shows a cross section of a piston diaphragm pump as is used in the mining and mineral processing industries for the transport of

Fluid simulations of ∇Te-driven turbulence and transport in boundary plasmas

International Nuclear Information System (INIS)

Xu, X.Q.; Cohen, R.H.

1993-01-01

This paper is a report on simulations of a new drift wave type instability driven by the electron temperature gradient in tokamak scrapeoff-layers (SOL). A 2D(x,y) fluid code has been developed in order to explore the anomalous transport in the boundary plasmas. The simulation consists of a set of fluid equations (in the electrostatic limit) for the vorticity ∇ perpendicular 2 φ, the electron density n e and the temperature T e in a shearless plasma slab confined by a uniform, straight magnetic field B z with two diverter (or limiter) plates intercepting the magnetic field. The model has two regions separated by a magnetic separatrix: in the edge region inside the separatrix, the model is periodic along the magnetic field while in the SOL region outside the separatrix, the magnetic field is taken to be of finite length with model (logical sheath) boundary conditions at diverter (or limiter) plates. The simulation results show that the observed linear instability agrees well with theory, and that a saturated state of turbulence is reached. In saturated turbulence, clear evidence of the expected long-wavelength mode penetration into the edge is seen, an inverse cascade of wave energy (toward both long wavelengths and low frequencies) is observed. The simulation results also show that amplitudes of potential and the electron temperature fluctuations are somewhat above and the heat flux are somewhat below those of the simplest mixing-length estimates. The results from the self-consistent simulations to determine the microturbulent SOL electron temperature profile agree reasonably with the experimental measurements. The effects on the mode of neutral gas collisions at the divertor sheath and comparisons with the ionization driven turbulence are discussed

Short-term fluid, heat, and solute transport in deep 'georeservoirs' likely to become 'EGS': some challenges to ICDP hydrogeologists who might like using artificial tracers

Science.gov (United States)

Ghergut, Julia; Behrens, Horst; Huenges, Ernst; Rose, Peter; Sauter, Martin

2014-05-01

During Fall 2013, the Integrated Continental Scientific Drilling Programme (ICDP) set out to define a new Science Plan that shall replace its past-decade version (Harms et al., eds., 2005) for the decade to come. Geoscientists worldwide were welcomed to suggest new imaging and exploration methods, new sites to drill, new challenges to be addressed with a view at new 'societal needs' (Harms and Wiersberg 2013). Save for two outstanding exceptions at the Mutnovsky volcano in Russia and the KTB site in Germany, the use of artificial tracers, especially within forced-gradient tests, has not been on the agenda of most ICDP projects so far (other than for purposes of monitoring microbial contamination in conjunction with drilling activities); deep-reservoir exploration and characterization efforts were restrained to non-fluid-invasive techniques on the one hand, and to sites featuring some unique earth-historical traits, on the other hand. Surely, this was not for lack of interest in quantifying fluid transport in the deep subsurface in general, but mainly due to operational, technical, and financial constraints (lack of resources / lack of opportunity for significant fluid turnover within the target, deep-seated georeservoirs, and fear of persistent, large-scale georeservoir contamination by non-pristine fluids). - This is likely to change during the forthcoming decade(s), owing to worldwide increased interest in some 'georesource' or 'georeservoir' play types (Moeck 2013) that have not been in the ICDP focus so far, including non-volcanogenic geothermal, and allowing for man-made design and intervention into how those 'georesources' or 'georeservoirs' shall work for us. Among the latter, petrothermal systems (Jung 2013, Huenges and Jung 2004) acquire growing recognition as a promising (and maybe unique) option for baseload energy supply in vast areas of the Northern hemisphere, at very low emissions and (in the long run) moderate costs. With petrothermal coming into

Water Balance Simulations of a PEM Fuel Cell Using a Two-Fluid Model

DEFF Research Database (Denmark)

Berning, Torsten; Odgaard, Madeleine; Kær, Søren Knudsen

2010-01-01

A previously published computational multi-phase model of a polymer-electrolyte membrane fuel cell has been extended in order to account for the anode side and the electrolyte membrane. The model has been applied to study the water balance of a fuel cell during operation under various humidificat...... net water transport coefficient. Thus we can reduce flooding at the cathode and may obtain improved cell performance due to a better humidified membrane. The results also suggest that membrane dehydration may occur at either anode or cathode depending on the net water transport....

Natural convection in superposed fluid-porous layers

CERN Document Server

Bagchi, Aniruddha

2013-01-01

Natural Convection in Composite Fluid-Porous Domains provides a timely overview of the current state of understanding on the phenomenon of convection in composite fluid-porous layers. Natural convection in horizontal fluid-porous layers has received renewed attention because of engineering problems such as post-accident cooling of nuclear reactors, contaminant transport in groundwater, and convection in fibrous insulation systems. Because applications of the problem span many scientific domains, the book serves as a valuable resource for a wide audience.

The molecular mechanism for overcoming the rate-limiting step in monoamine neurotransmitter transport

DEFF Research Database (Denmark)

Sinning, Steffen; Said, Saida; Malinauskaite, Lina

The monoamine transporter family consists of dopamine (DAT), norepinephrine (NET) and serotonin transporters (SERT) that mediate the reuptake of the monoamine neurotransmitters after their release during neurotransmission. These transporters play prominent roles in psychiatric disorders and are t......The monoamine transporter family consists of dopamine (DAT), norepinephrine (NET) and serotonin transporters (SERT) that mediate the reuptake of the monoamine neurotransmitters after their release during neurotransmission. These transporters play prominent roles in psychiatric disorders...... membrane. The rate-limiting step in monoamine reuptake is the return of the empty transporter from an inward-facing to an outward-facing conformation without neurotransmitter and sodium bound. The molecular mechanism underlying this important conformational transition has not been described. Crystal...

Net Neutrality

DEFF Research Database (Denmark)

Savin, Andrej

2017-01-01

Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else.......Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else....

Supercritical fluid reverse micelle separation

Science.gov (United States)

Fulton, J.L.; Smith, R.D.

1993-11-30

A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

Annotating Coloured Petri Nets

DEFF Research Database (Denmark)

Lindstrøm, Bo; Wells, Lisa Marie

2002-01-01

Coloured Petri nets (CP-nets) can be used for several fundamentally different purposes like functional analysis, performance analysis, and visualisation. To be able to use the corresponding tool extensions and libraries it is sometimes necessary to include extra auxiliary information in the CP......-net. An example of such auxiliary information is a counter which is associated with a token to be able to do performance analysis. Modifying colour sets and arc inscriptions in a CP-net to support a specific use may lead to creation of several slightly different CP-nets – only to support the different uses...... of the same basic CP-net. One solution to this problem is that the auxiliary information is not integrated into colour sets and arc inscriptions of a CP-net, but is kept separately. This makes it easy to disable this auxiliary information if a CP-net is to be used for another purpose. This paper proposes...

Porous media fluid transport and pore structure

CERN Document Server

Dullien, F A L

1992-01-01

This book examines the relationship between transport properties and pore structure of porous material. Models of pore structure are presented with a discussion of how such models can be used to predict the transport properties of porous media. Portions of the book are devoted to interpretations of experimental results in this area and directions for future research. Practical applications are given where applicable, and are expected to be useful for a large number of different fields, including reservoir engineering, geology, hydrogeology, soil science, chemical process engineering, biomedica

NetSig

DEFF Research Database (Denmark)

Horn, Heiko; Lawrence, Michael S; Chouinard, Candace R

2018-01-01

Methods that integrate molecular network information and tumor genome data could complement gene-based statistical tests to identify likely new cancer genes; but such approaches are challenging to validate at scale, and their predictive value remains unclear. We developed a robust statistic (Net......Sig) that integrates protein interaction networks with data from 4,742 tumor exomes. NetSig can accurately classify known driver genes in 60% of tested tumor types and predicts 62 new driver candidates. Using a quantitative experimental framework to determine in vivo tumorigenic potential in mice, we found that Net......Sig candidates induce tumors at rates that are comparable to those of known oncogenes and are ten-fold higher than those of random genes. By reanalyzing nine tumor-inducing NetSig candidates in 242 patients with oncogene-negative lung adenocarcinomas, we find that two (AKT2 and TFDP2) are significantly amplified...

Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

DEFF Research Database (Denmark)

Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

2014-01-01

We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C. P...

Comparison of kinetic and fluid neutral models for attached and detached state

International Nuclear Information System (INIS)

Furubayashi, M.; Hoshino, K.; Toma, M.; Hatayama, A.; Coster, D.; Schneider, R.; Bonnin, X.; Kawashima, H.; Asakura, N.; Suzuki, Y.

2009-01-01

Neutral behavior has an important role in the transport simulations of the edge plasma. Most of the edge plasma transport codes treat neutral particles by a simple fluid model or a kinetic model. The fluid model allows faster calculations. However, the applicability of the fluid model is limited. In this study, simulation results of JT-60U from kinetic neutral model and fluid neutral model are compared under the attached and detached state, using the 2D edge plasma code package, SOLPS5.0. In the SOL region, no significant differences are observed in the upstream plasma profiles between kinetic and fluid neutral models. However, in the divertor region, large differences are observed in plasma and neutral profiles. Therefore, further optimization of the fluid neutral model should be performed. Otherwise kinetic neutral model should be used to analyze the divertor region.

Crystalloids versus colloids: implications in fluid therapy of dogs with intestinal obstruction.

Science.gov (United States)

Allen, D; Kvietys, P R; Granger, D N

1986-08-01

Responses of jejunal transcapillary and transmucosal fluid fluxes to IV infusion of crystalloid or colloid solutions were evaluated in 12 dogs. One isolated intestinal segment in each dog was used as the control segment, and 2 segments were distended to a intraluminal hydrostatic pressure of 10 cm of H2O. The artery supplying 1 of the 2 distended (autoperfused) segments was cannulated and perfused with blood from the femoral artery. One of the 2 distended segments was autoperfused from the femoral artery. Intraluminal pressure was increased in the autoperfused segment and in 1 other segment for three, 20-minute periods after administration of the crystalloid or colloid solution. Net transmucosal fluid flux was estimated, using a volume recovery method. In each autoperfused segment, blood flow, capillary pressure, lymph flow, and plasma protein and lymph protein concentrations were measured during each 20-minute distention period. Systemic arterial pressure was monitored throughout the procedure. Plasma and tissue oncotic pressures were calculated from the plasma protein and lymph protein concentrations. Total vascular resistance and precapillary and postcapillary resistances were determined. Capillary pressure increased after infusion with colloids and crystalloids, with the effects being more prolonged in the colloid group. Plasma oncotic pressure transiently increased after infusion with colloids and decreased after infusion with crystalloids. Lymph flow increased only in crystalloid-treated dogs. Due to alterations in transcapillary fluid filtration, crystalloids induced a net loss of fluid into the intestinal lumen, whereas the fluid absorptive capacity of the jejunum was unaltered by colloid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Learning Visual Basic NET

CERN Document Server

Liberty, Jesse

2009-01-01

Learning Visual Basic .NET is a complete introduction to VB.NET and object-oriented programming. By using hundreds of examples, this book demonstrates how to develop various kinds of applications--including those that work with databases--and web services. Learning Visual Basic .NET will help you build a solid foundation in .NET.

Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle

Science.gov (United States)

Reidy, P. T.; Walker, D. K.; Dickinson, J. M.; Gundermann, D. M.; Drummond, M. J.; Timmerman, K. L.; Cope, M. B.; Mukherjea, R.; Jennings, K.; Volpi, E.

2014-01-01

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups (P protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein (P protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein. PMID:24699854

Kubo formulas for relativistic fluids in strong magnetic fields

International Nuclear Information System (INIS)

Huang Xuguang; Sedrakian, Armen; Rischke, Dirk H.

2011-01-01

Magnetohydrodynamics of strongly magnetized relativistic fluids is derived in the ideal and dissipative cases, taking into account the breaking of spatial symmetries by a quantizing magnetic field. A complete set of transport coefficients, consistent with the Curie and Onsager principles, is derived for thermal conduction, as well as shear and bulk viscosities. It is shown that in the most general case the dissipative function contains five shear viscosities, two bulk viscosities, and three thermal conductivity coefficients. We use Zubarev's non-equilibrium statistical operator method to relate these transport coefficients to correlation functions of the equilibrium theory. The desired relations emerge at linear order in the expansion of the non-equilibrium statistical operator with respect to the gradients of relevant statistical parameters (temperature, chemical potential, and velocity.) The transport coefficients are cast in a form that can be conveniently computed using equilibrium (imaginary-time) infrared Green's functions defined with respect to the equilibrium statistical operator. - Highlights: → Strong magnetic fields can make charged fluids behave anisotropically. → Magnetohydrodynamics for these fluids contains 5 shear, 2 bulk viscosities, and 3 heat conductivities. → We derive Kubo formulas for these transport coefficients.

Acute exposure to space flight results in evidence of reduced lymph Transport, tissue fluid Shifts, and immune alterations in the rat gastrointestinal system

Science.gov (United States)

Cromer, W. E.; Zawieja, D. C.

2018-05-01

Space flight causes a number of alterations in physiological systems, changes in the immunological status of subjects, and altered interactions of the host to environmental stimuli. We studied the effect of space flight on the lymphatic system of the gastrointestinal tract which is responsible for lipid transport and immune surveillance which includes the host interaction with the gut microbiome. We found that there were signs of tissue damage present in the space flown animals that was lacking in ground controls (epithelial damage, crypt morphological changes, etc.). Additionally, morphology of the lymphatic vessels in the tissue suggested a collapsed state at time of harvest and there was a profound change in the retention of lipid in the villi of the ileum. Contrary to our assumptions there was a reduction in tissue fluid volume likely associated with other fluid shifts described. The reduction of tissue fluid volume in the colon and ileum is a likely contributing factor to the state of the lymphatic vessels and lipid transport issues observed. There were also associated changes in the number of MHC-II+ immune cells in the colon tissue, which along with reduced lymphatic competence would favor immune dysfunction in the tissue. These findings help expand our understanding of the effects of space flight on various organ systems. It also points out potential issues that have not been closely examined and have to potential for the need of countermeasure development.

U(VI) speciation and reduction in acid chloride fluids in hydrothermal conditions: from transport to deposition of uranium in unconformity-related deposits

International Nuclear Information System (INIS)

Dargent, Maxime

2014-01-01

Circulations of acidic chloride brines in the earth's crust are associated with several types of uranium deposits, particularly unconformity-related uranium (URU) deposits. The spectacular high grade combined with the large tonnage of these deposits is at the origin of the key questions concerning the geological processes responsible for U transport and precipitation. The aim of this work is to performed experimental studies of U(VI) speciation and its reduction to U(IV) subsequently precipitation to uraninite under hydrothermal condition. About uranium transport, the study of U(VI) speciation in acidic brines at high temperature is performed by Raman and XAS spectroscopy, showing the coexistence of several uranyl chloride complexes UO 2 Cl n 2-n (n = 0 - 5). From this study, complexation constants are proposed. The strong capability of chloride to complex uranyl is at the origin of the transport of U(VI) at high concentration in acidic chloride brines. Concerning uranium precipitation, the reactivity of four potential reductants under conditions relevant for URU deposits genesis is investigated: H 2 , CH 4 , Fe(II) and the C-graphite. The kinetics of reduction reaction is measured as a function of temperature, salinity, pH and concentration of reductant. H 2 , CH 4 , and the C-graphite are very efficient while Fe(II) is not able to reduce U(VI) in same conditions. The duration of the mineralizing event is controlled by (i) the U concentration in the ore-forming fluids and (ii) by the generation of gaseous reductants, and not by the reduction kinetics. These mobile and efficient gaseous reductant could be at the origin of the extremely focus and massive character of ore in URU deposits. Finally, first partition coefficients uraninite/fluid of trace elements are obtained. This last part opens-up new perspectives on (i) REE signatures interpretation for a given type of uranium deposit (ii) and reconstruction of mineralizing fluids composition. (author) [fr

Inertial Effects on Flow and Transport in Heterogeneous Porous Media.

Science.gov (United States)

Nissan, Alon; Berkowitz, Brian

2018-02-02

We investigate the effects of high fluid velocities on flow and tracer transport in heterogeneous porous media. We simulate fluid flow and advective transport through two-dimensional pore-scale matrices with varying structural complexity. As the Reynolds number increases, the flow regime transitions from linear to nonlinear; this behavior is controlled by the medium structure, where higher complexity amplifies inertial effects. The result is, nonintuitively, increased homogenization of the flow field, which leads in the context of conservative chemical transport to less anomalous behavior. We quantify the transport patterns via a continuous time random walk, using the spatial distribution of the kinetic energy within the fluid as a characteristic measure.

Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

Directory of Open Access Journals (Sweden)

Jesper G. Andreasen

2016-04-01

Full Text Available For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low-temperature heat at 90 ∘ C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35 mole . The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32 at the same total cost of 1200 k$.

Quantification of free water transport in peritoneal dialysis

NARCIS (Netherlands)

Smit, Watske; Struijk, Dirk G.; Ho-Dac-Pannekeet, Marja M.; Krediet, Raymond T.

2004-01-01

BACKGROUND: In peritoneal dialysis (PD) total net ultrafiltration (NUF) is dependent on transport through small pores and through water channels in the peritoneum. These channels are impermeable to solutes, and therefore, crystalloid osmotic-induced free water transport occurs through them. Several

[A transportation vehicle for laparoscopically obtained follicular specimens].

Science.gov (United States)

Fliess, F R; Sudik, R

1984-01-01

Structure, function and first results with a vehicle for transportation were described. This apparatus allows to store laparoscopic harvested follicular fluids for a while in constant temperature and in air condition with 5% CO2 in compressed air. Simultaneously the follicular fluids were transported in this vehicle from operating theatre to the laboratory.

Phase space density representations in fluid dynamics

International Nuclear Information System (INIS)

Ramshaw, J.D.

1989-01-01

Phase space density representations of inviscid fluid dynamics were recently discussed by Abarbanel and Rouhi. Here it is shown that such representations may be simply derived and interpreted by means of the Liouville equation corresponding to the dynamical system of ordinary differential equations that describes fluid particle trajectories. The Hamiltonian and Poisson bracket for the phase space density then emerge as immediate consequences of the corresponding structure of the dynamics. For barotropic fluids, this approach leads by direct construction to the formulation presented by Abarbanel and Rouhi. Extensions of this formulation to inhomogeneous incompressible fluids and to fluids in which the state equation involves an additional transported scalar variable are constructed by augmenting the single-particle dynamics and phase space to include the relevant additional variable

Net atmospheric mercury deposition to Svalbard: Estimates from lacustrine sediments

Science.gov (United States)

Drevnick, Paul E.; Yang, Handong; Lamborg, Carl H.; Rose, Neil L.

2012-11-01

In this study we used lake sediments, which faithfully record Hg inputs, to derive estimates of net atmospheric Hg deposition to Svalbard, Norwegian Arctic. With the exception of one site affected by local pollution, the study lakes show twofold to fivefold increases in sedimentary Hg accumulation since 1850, likely due to long-range atmospheric transport and deposition of anthropogenic Hg. Sedimentary Hg accumulation in these lakes is a linear function of the ratio of catchment area to lake area, and we used this relationship to model net atmospheric Hg flux: preindustrial and modern estimates are 2.5 ± 3.3 μg m-2 y-1 and 7.0 ± 3.0 μg m-2 y-1, respectively. The modern estimate, by comparison with data for Hg wet deposition, indicates that atmospheric mercury depletion events (AMDEs) or other dry deposition processes contribute approximately half (range 0-70%) of the net flux. Hg from AMDEs may be moving in significant quantities into aquatic ecosystems, where it is a concern because of contamination of aquatic food webs.

On the fluid mechanics of fires

Energy Technology Data Exchange (ETDEWEB)

TIESZEN,SHELDON R.

2000-02-29

Fluid mechanics research related to fire is reviewed with focus on canonical flows, multiphysics coupling aspects, experimental and numerical techniques. Fire is a low-speed, chemically-reacting, flow in which buoyancy plans an important role. Fire research has focused on two canonical flows, the reacting boundary-layer and the reacting free plume. There is rich, multi-lateral, bi-directional, coupling among fluid mechanics and scalar transport, combustion, and radiation. There is only a limited experimental fluid-mechanics database for fire due to measurement difficulties in the harsh environment, and the focus within the fire community on thermal/chemical consequences. Increasingly, computational fluid dynamics techniques are being used to provide engineering guidance on thermal/chemical consequences and to study fire phenomenology.

NET in-vessel vehicle system

International Nuclear Information System (INIS)

Jones, H.

1991-02-01

The CFFTP/Spar In-vessel Vehicle System concept for in-vessel remote maintenance of the NET/ITER machine is described. It comprises a curved deployable boom, a vehicle which can travel on the boom and an end effector or work unit mounted on the vehicle. The stowed boom, vehicle, and work unit are inserted via the equatorial access port of the torus. Following insertion the boom is deployed and locked in place. The vehicle may then travel along the boom to transport the work unit to any desired location. A novel feature of the concept is the deployable boom. When fully deployed, it closely resembles a conventional curved truss structure in configuration and characteristics. However, the joints of the truss structure are hinged so that it can fold into a compact package, of less than 20% of deployed volume for storage, transportation and insertion into the torus. A full-scale 2-metre long section of this boom was produced for demonstration purposes. As part of the concept definition the work unit for divertor handling was studied to demonstrate that large payloads could be manipulated within the confines of the torus using the in-vessel vehicle system. Principal advantages of the IVVS are its high load capacity and rigidity, low weight and stowed volume, simplicity of control and operation, and its relatively high speed of transportation

Neutron flux investigation on certain alternative fluids in a hybrid system by using MCNPX Monte Carlo transport code

Energy Technology Data Exchange (ETDEWEB)

Guenay, Mehtap [Inoenue Univ., Malatya (Turkey). Physics Dept.

2014-04-15

In this study, the molten salt-heavy metal mixtures 93-85 % Li{sub 20}Sn{sub 80} + 5 % SFG-PuO{sub 2} and 2-10 % UO{sub 2}, 93-85 % Li{sub 20}Sn{sub 80} + 5 % SFG-PuO{sub 2} and 2-10 % NpO{sub 2}, 93-85 % Li{sub 20}Sn{sub 80} + 5 % SFG-PuO{sub 2} and 2-10 % UCO were used as fluids. The fluids were used in the liquid first wall, blanket and shield zones of the designed hybrid reactor system. Four centimeter thick 9Cr2WVTa ferritic steel was used as the structural material. In this study, the effect of mixture components on the neutron flux was investigated in a designed fusion-fission hybrid reactor system. The neutron flux was investigated according to the mixture components, radial flux distribution and energy spectrum in the designed system. Three-dimensional analyses were performed using the most recent MCNPX-2.7.0 Monte Carlo radiation transport code and the ENDF/B-VII.0 nuclear data library. (orig.)

FRACTURING FLUID CHARACTERIZATION FACILITY

Energy Technology Data Exchange (ETDEWEB)

Subhash Shah

2000-08-01

Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

Pro-Nets versus No-Nets: Differences in Urban Older Adults' Predilections for Internet Use

Science.gov (United States)

Cresci, M. Kay; Yarandi, Hossein N.; Morrell, Roger W.

2010-01-01

Enthusiasm for information technology (IT) is growing among older adults. Many older adults enjoy IT and the Internet (Pro-Nets), but others have no desire to use it (No-Nets). This study found that Pro-Nets and No-Nets were different on a number of variables that might predict IT use. No-Nets were older, had less education and income, were…

Statistically derived conservation equations for fluid particle flows

International Nuclear Information System (INIS)

Reyes, J.N. Jr.

1989-01-01

The behavior of water droplets in a heated nuclear fuel channel is of significant interest to nuclear reactor safety studies pertaining to loss-of-coolant accidents. This paper presents the derivation of the mass, momentum, and energy conservation equations for a distribution of fluid particles (bubbles or droplets) transported by a continuous fluid medium. When coupled with the appropriate closure equations, the conservation equations can be used to model nonequilibrium, two-phase, dispersed, fluid flow behavior

Experiments and simulation of a net closing mechanism for tether-net capture of space debris

Science.gov (United States)

Sharf, Inna; Thomsen, Benjamin; Botta, Eleonora M.; Misra, Arun K.

2017-10-01

This research addresses the design and testing of a debris containment system for use in a tether-net approach to space debris removal. The tether-net active debris removal involves the ejection of a net from a spacecraft by applying impulses to masses on the net, subsequent expansion of the net, the envelopment and capture of the debris target, and the de-orbiting of the debris via a tether to the chaser spacecraft. To ensure a debris removal mission's success, it is important that the debris be successfully captured and then, secured within the net. To this end, we present a concept for a net closing mechanism, which we believe will permit consistently successful debris capture via a simple and unobtrusive design. This net closing system functions by extending the main tether connecting the chaser spacecraft and the net vertex to the perimeter and around the perimeter of the net, allowing the tether to actuate closure of the net in a manner similar to a cinch cord. A particular embodiment of the design in a laboratory test-bed is described: the test-bed itself is comprised of a scaled-down tether-net, a supporting frame and a mock-up debris. Experiments conducted with the facility demonstrate the practicality of the net closing system. A model of the net closure concept has been integrated into the previously developed dynamics simulator of the chaser/tether-net/debris system. Simulations under tether tensioning conditions demonstrate the effectiveness of the closure concept for debris containment, in the gravity-free environment of space, for a realistic debris target. The on-ground experimental test-bed is also used to showcase its utility for validating the dynamics simulation of the net deployment, and a full-scale automated setup would make possible a range of validation studies of other aspects of a tether-net debris capture mission.

Comprehensive computational model for combining fluid hydrodynamics, light transport and biomass growth in a Taylor vortex algal photobioreactor: Lagrangian approach.

Science.gov (United States)

Gao, Xi; Kong, Bo; Vigil, R Dennis

2017-01-01

A comprehensive quantitative model incorporating the effects of fluid flow patterns, light distribution, and algal growth kinetics on biomass growth rate is developed in order to predict the performance of a Taylor vortex algal photobioreactor for culturing Chlorella vulgaris. A commonly used Lagrangian strategy for coupling the various factors influencing algal growth was employed whereby results from computational fluid dynamics and radiation transport simulations were used to compute numerous microorganism light exposure histories, and this information in turn was used to estimate the global biomass specific growth rate. The simulations provide good quantitative agreement with experimental data and correctly predict the trend in reactor performance as a key reactor operating parameter is varied (inner cylinder rotation speed). However, biomass growth curves are consistently over-predicted and potential causes for these over-predictions and drawbacks of the Lagrangian approach are addressed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diffusion of Supercritical Fluids through Single-Layer Nanoporous Solids: Theory and Molecular Simulations.

Science.gov (United States)

Oulebsir, Fouad; Vermorel, Romain; Galliero, Guillaume

2018-01-16

With the advent of graphene material, membranes based on single-layer nanoporous solids appear as promising devices for fluid separation, be it liquid or gaseous mixtures. The design of such architectured porous materials would greatly benefit from accurate models that can predict their transport and separation properties. More specifically, there is no universal understanding of how parameters such as temperature, fluid loading conditions, or the ratio of the pore size to the fluid molecular diameter influence the permeation process. In this study, we address the problem of pure supercritical fluids diffusing through simplified models of single-layer porous materials. Basically, we investigate a toy model that consists of a single-layer lattice of Lennard-Jones interaction sites with a slit gap of controllable width. We performed extensive equilibrium and biased molecular dynamics simulations to document the physical mechanisms involved at the molecular scale. We propose a general constitutive equation for the diffusional transport coefficient derived from classical statistical mechanics and kinetic theory, which can be further simplified in the ideal gas limit. This transport coefficient relates the molecular flux to the fluid density jump across the single-layer membrane. It is found to be proportional to the accessible surface porosity of the single-layer porous solid and to a thermodynamic factor accounting for the inhomogeneity of the fluid close to the pore entrance. Both quantities directly depend on the potential of mean force that results from molecular interactions between solid and fluid atoms. Comparisons with the simulations data show that the kinetic model captures how narrowing the pore size below the fluid molecular diameter lowers dramatically the value of the transport coefficient. Furthermore, we demonstrate that our general constitutive equation allows for a consistent interpretation of the intricate effects of temperature and fluid loading

FY 2000 Project of international clean energy network using hydrogen conversion (WE-NET)

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Described herein are the FY 2000 results of the research and development project aimed at construction of the international clean energy network using hydrogen conversion (WE-NET). The projects include 12 tasks; system evaluation for, e.g., optimum scenario for introduction of hydrogen energy; experiments for hydrogen safety; study on the international cooperation for WE-NET; development of power generation technology using a 100kW cogeneration system including hydrogen-firing diesel engine; developmental research on vehicles driven by a hydrogen fuel cell system; developmental research on the basic technologies for PEFC utilizing pure hydrogen; developmental research on a 30Nm{sup 3}/hour hydrogen refueling station for vehicles; developmental research on hydrogen production technology; developmental research on hydrogen transportation and storage technology, e.g., liquid hydrogen pump; research and development of the databases of and processing technology for cryogenic materials exposed to liquid hydrogen; developmental research on hydrogen absorbing alloys for small-scale hydrogen transportation and storage systems; and study on innovative and leading technologies. (NEDO)

Fluid flow behaviour of gas-condensate and near-miscible fluids at the pore scale

Energy Technology Data Exchange (ETDEWEB)

Dawe, Richard A. [Department of Chemical Engineering, University of West Indies, St. Augustine (Trinidad and Tobago); Grattoni, Carlos A. [Department of Earth Science and Engineering, Imperial College, London, SW7 2BP (United Kingdom)

2007-02-15

Retrograde condensate reservoir behaviour is complex with much of the detailed mechanisms of the multiphase fluid transport and mass transfer between the phases within the porous matrix still speculative. Visual modelling of selected processes occurring at the pore level under known and controlled boundary conditions can give an insight to fluid displacements at the core scale and help the interpretation of production behaviour at reservoir scale. Visualisation of the pore scale two-phase flow mechanisms has been studied experimentally at low interfacial tensions, < 0.5 mN/m, using a partially miscible fluid system in glass visual micro models. As the interfacial tension decreases the balance between fluid-fluid forces (interfacial, spreading and viscous) and fluid-solid interactions (wettability and viscous interactions) changes. Data measurements in the laboratory, particularly relative permeability, will therefore always be difficult especially for condensate fluids just below their dew point. What is certain is that gas production from a gas-condensate leads to condensate dropout when pressure falls below the dew point, either within the wellbore or, more importantly, in the reservoir. This paper illustrates some pore scale physics, particularly interfacial phenomena at low interfacial tension, which has relevance to appreciating the flow of condensate fluids close to their dew point either near the wellbore (which affects well productivity) or deep inside the reservoir (which affects condensate recovery). (author)

Methods of producing transportation fuel

Science.gov (United States)

Nair, Vijay [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Cherrillo, Ralph Anthony [Houston, TX; Bauldreay, Joanna M [Chester, GB

2011-12-27

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing transportation fuel is described herein. The method for producing transportation fuel may include providing formation fluid having a boiling range distribution between -5.degree. C. and 350.degree. C. from a subsurface in situ heat treatment process to a subsurface treatment facility. A liquid stream may be separated from the formation fluid. The separated liquid stream may be hydrotreated and then distilled to produce a distilled stream having a boiling range distribution between 150.degree. C. and 350.degree. C. The distilled liquid stream may be combined with one or more additives to produce transportation fuel.

Numerical investigation of fluid mud motion using a three-dimensional hydrodynamic and two-dimensional fluid mud coupling model

Science.gov (United States)

Yang, Xiaochen; Zhang, Qinghe; Hao, Linnan

2015-03-01

A water-fluid mud coupling model is developed based on the unstructured grid finite volume coastal ocean model (FVCOM) to investigate the fluid mud motion. The hydrodynamics and sediment transport of the overlying water column are solved using the original three-dimensional ocean model. A horizontal two-dimensional fluid mud model is integrated into the FVCOM model to simulate the underlying fluid mud flow. The fluid mud interacts with the water column through the sediment flux, current, and shear stress. The friction factor between the fluid mud and the bed, which is traditionally determined empirically, is derived with the assumption that the vertical distribution of shear stress below the yield surface of fluid mud is identical to that of uniform laminar flow of Newtonian fluid in the open channel. The model is validated by experimental data and reasonable agreement is found. Compared with numerical cases with fixed friction factors, the results simulated with the derived friction factor exhibit the best agreement with the experiment, which demonstrates the necessity of the derivation of the friction factor.

Prenatal programming of rat cortical collecting tubule sodium transport.

Science.gov (United States)

Cheng, Chih-Jen; Lozano, German; Baum, Michel

2012-03-15

Prenatal insults have been shown to lead to elevated blood pressure in offspring when they are studied as adults. Prenatal administration of dexamethasone and dietary protein deprivation have demonstrated that there is an increase in transporter abundance for a number of nephron segments but not the subunits of the epithelial sodium channel (ENaC) in the cortical collecting duct. Recent studies have shown that aldosterone is elevated in offspring of protein-deprived mothers when studied as adults, but the physiological importance of the increase in serum aldosterone is unknown. As an indirect measure of ENaC activity, we compared the natriuretic response to benzamil in offspring of mothers who ate a low-protein diet (6%) with those who ate a normal diet (20%) for the last half of pregnancy. The natriuretic response to benzamil was greater in the 6% group (821.1 ± 161.0 μmol/24 h) compared with the 20% group (279.1 ± 137.0 μmol/24 h), consistent with greater ENaC activity in vivo (P sodium transport (-1.9 ± 3.1 pmol·mm(-1)·min(-1)), the offspring of rats that ate a 6% protein diet during the last half of pregnancy had a net sodium flux of 10.7 ± 2.6 pmol·mm(-1)·min(-1) (P = 0.01) in tubules perfused in vitro. Sodium transport was measured using ion-selective electrodes, a novel technique allowing measurement of sodium in nanoliter quantities of fluid. Thus we directly demonstrate that there is prenatal programming of cortical collecting duct sodium transport.

Multiphase flow and transport in porous media

Science.gov (United States)

Parker, J. C.

1989-08-01

Multiphase flow and transport of compositionally complex fluids in geologic media is of importance in a number of applied problems which have major social and economic effects. In petroleum reservoir engineering, efficient recovery of energy reserves is the principal goal. Unfortunately, some of these hydrocarbons and other organic chemicals often find their way unwanted into the soils and groundwater supplies. Removal in the latter case is predicated on ensuring the public health and safety. In this paper, principles of modeling fluid flow in systems containing up to three fluid phases (namely, water, air, and organic liquid) are described. Solution of the governing equations for multiphase flow requires knowledge of functional relationships between fluid pressures, saturations, and permeabilities which may be formulated on the basis of conceptual models of fluid-porous media interactions. Mechanisms of transport in multicomponent multiphase systems in which species may partition between phases are also described, and the governing equations are presented for the case in which local phase equilibrium may be assumed. A number of hypothetical numerical problems are presented to illustrate the physical behavior of systems in which multiphase flow and transport arise.

Turbulent mixing between subchannels in a gas-liquid two-phase flow. For the equilibrium flow without net fluid transfer between subchannels

International Nuclear Information System (INIS)

Kawahara, Akimaro; Sadatomi, Michio; Sato, Yoshifusa; Saito, Hidetoshi.

1995-01-01

To provide data necessary for modeling turbulent mixing between subchannels in a nuclear fuel rod bundle, three experiments were made in series for equilibrium two-phase flows, in which net mass exchange does not occur between subchannels for each phase. The first one was the measurement of turbulent mixing rates of both gas and liquid phases by a tracer technique, using air and water as the working fluids. Three kinds of vertical test channels consisting of two subchannels were used. The data have shown that the turbulent mixing rate of each phase in a two-phase flow is strongly dependent on flow regime. So, to see the relation between turbulent mixing and two-phase flow configuration in the subchannels, the second experiment, flow visualization, was made. It was observed in slug and churn flows that a lateral inter-subchannel liquid flow of a large scale is caused by the successive axial transit of large gas bubbles in each subchannel, and the turbulent mixing for the liquid phase is dominated by this lateral flow. To investigate a driving force of such large scale lateral flow, the third experiment, the measurement of an instantaneous pressure differential between the subchannels, was made. The result showed that there is a close relationship between the liquid phase mixing rate and the magnitude of the pressure differential fluctuation. (author)

Rheology of Active Fluids

Science.gov (United States)

Saintillan, David

2018-01-01

An active fluid denotes a viscous suspension of particles, cells, or macromolecules able to convert chemical energy into mechanical work by generating stresses on the microscale. By virtue of this internal energy conversion, these systems display unusual macroscopic rheological signatures, including a curious transition to an apparent superfluid-like state where internal activity exactly compensates viscous dissipation. These behaviors are unlike those of classical complex fluids and result from the coupling of particle configurations with both externally applied flows and internally generated fluid disturbances. Focusing on the well-studied example of a suspension of microswimmers, this review summarizes recent experiments, models, and simulations in this area and highlights the critical role played by the rheological response of these active materials in a multitude of phenomena, from the enhanced transport of passive suspended objects to the emergence of spontaneous flows and collective motion.

ROOT.NET: Using ROOT from .NET languages like C# and F#

Science.gov (United States)

Watts, G.

2012-12-01

ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F# (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

ROOT.NET: Using ROOT from .NET languages like C and F

International Nuclear Information System (INIS)

Watts, G

2012-01-01

ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

Gravitational Anomaly and Transport Phenomena

International Nuclear Information System (INIS)

Landsteiner, Karl; Megias, Eugenio; Pena-Benitez, Francisco

2011-01-01

Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas. We evaluate the Kubo formula for the anomalous vortical conductivity at weak coupling and show that it receives contributions proportional to the gravitational anomaly coefficient. The gravitational anomaly gives rise to an anomalous vortical effect even for an uncharged fluid.

In-beam experience with a highly granular DAQ and control network: TrbNet

International Nuclear Information System (INIS)

Michel, J; Korcyl, G; Maier, L; Traxler, M

2013-01-01

Virtually all Data Acquisition Systems (DAQ) for nuclear and particle physics experiments use a large number of Field Programmable Gate Arrays (FPGAs) for data transport and more complex tasks as pattern recognition and data reduction. All these FPGAs in a large system have to share a common state like a trigger number or an epoch counter to keep the system synchronized for a consistent event/epoch building. Additionally, the collected data has to be transported with high bandwidth, optionally via the ubiquitous Ethernet protocol. Furthermore, the FPGAs' internal states and configuration memories have to be accessed for control and monitoring purposes. Another requirement for a modern DAQ-network is the fault-tolerance for intermittent data errors in the form of automatic retransmission of faulty data. As FPGAs suffer from Single Event Effects when exposed to ionizing particles, the system has to deal with failing FPGAs. The TrbNet protocol was developed taking all these requirements into account. Three virtual channels are merged on one physical medium: The trigger/epoch information is transported with the highest priority. The data channel is second in the priority order, while the control channel is the last. Combined with a small frame size of 80 bit this guarantees a low latency data transport: A system with 100 front-ends can be built with a one-way latency of 2.2 us. The TrbNet-protocol was implemented in each of the 550 FPGAs of the HADES upgrade project and has been successfully used during the Au+Au campaign in April 2012. With 2⋅10 6 /s Au-ions and 3% interaction ratio the accepted trigger rate is 10 kHz while data is written to storage with 150 MBytes/s. Errors are reliably mitigated via the implemented retransmission of packets and auto-shut-down of individual links. TrbNet was also used for full monitoring of the FEE status. The network stack is written in VHDL and was successfully deployed on various Lattice and Xilinx devices. The TrbNet is also

In-beam experience with a highly granular DAQ and control network: TrbNet

Science.gov (United States)

Michel, J.; Korcyl, G.; Maier, L.; Traxler, M.

2013-02-01

Virtually all Data Acquisition Systems (DAQ) for nuclear and particle physics experiments use a large number of Field Programmable Gate Arrays (FPGAs) for data transport and more complex tasks as pattern recognition and data reduction. All these FPGAs in a large system have to share a common state like a trigger number or an epoch counter to keep the system synchronized for a consistent event/epoch building. Additionally, the collected data has to be transported with high bandwidth, optionally via the ubiquitous Ethernet protocol. Furthermore, the FPGAs' internal states and configuration memories have to be accessed for control and monitoring purposes. Another requirement for a modern DAQ-network is the fault-tolerance for intermittent data errors in the form of automatic retransmission of faulty data. As FPGAs suffer from Single Event Effects when exposed to ionizing particles, the system has to deal with failing FPGAs. The TrbNet protocol was developed taking all these requirements into account. Three virtual channels are merged on one physical medium: The trigger/epoch information is transported with the highest priority. The data channel is second in the priority order, while the control channel is the last. Combined with a small frame size of 80 bit this guarantees a low latency data transport: A system with 100 front-ends can be built with a one-way latency of 2.2 us. The TrbNet-protocol was implemented in each of the 550 FPGAs of the HADES upgrade project and has been successfully used during the Au+Au campaign in April 2012. With 2ṡ106/s Au-ions and 3% interaction ratio the accepted trigger rate is 10 kHz while data is written to storage with 150 MBytes/s. Errors are reliably mitigated via the implemented retransmission of packets and auto-shut-down of individual links. TrbNet was also used for full monitoring of the FEE status. The network stack is written in VHDL and was successfully deployed on various Lattice and Xilinx devices. The TrbNet is also

INMARSAT-C SafetyNET

Science.gov (United States)

Tsunamis 406 EPIRB's National Weather Service Marine Forecasts INMARSAT-C SafetyNET Marine Forecast Offices greater danger near shore or any shallow waters? NATIONAL WEATHER SERVICE PRODUCTS VIA INMARSAT-C SafetyNET Inmarsat-C SafetyNET is an internationally adopted, automated satellite system for promulgating

Physically-Based Rendering of Particle-Based Fluids with Light Transport Effects

Science.gov (United States)

Beddiaf, Ali; Babahenini, Mohamed Chaouki

2018-03-01

Recent interactive rendering approaches aim to efficiently produce images. However, time constraints deeply affect their output accuracy and realism (many light phenomena are poorly or not supported at all). To remedy this issue, in this paper, we propose a physically-based fluid rendering approach. First, while state-of-the-art methods focus on isosurface rendering with only two refractions, our proposal (1) considers the fluid as a heterogeneous participating medium with refractive boundaries, and (2) supports both multiple refractions and scattering. Second, the proposed solution is fully particle-based in the sense that no particles transformation into a grid is required. This interesting feature makes it able to handle many particle types (water, bubble, foam, and sand). On top of that, a medium with different fluids (color, phase function, etc.) can also be rendered.

Equilibrium and nonequilibrium dynamics of soft sphere fluids.

Science.gov (United States)

Ding, Yajun; Mittal, Jeetain

2015-07-14

We use computer simulations to test the freezing-point scaling relationship between equilibrium transport coefficients (self-diffusivity, viscosity) and thermodynamic parameters for soft sphere fluids. The fluid particles interact via the inverse-power potential (IPP), and the particle softness is changed by modifying the exponent of the distance-dependent potential term. In the case of IPP fluids, density and temperature are not independent variables and can be combined to obtain a coupling parameter to define the thermodynamic state of the system. We find that the rescaled coupling parameter, based on its value at the freezing point, can approximately collapse the diffusivity and viscosity data for IPP fluids over a wide range of particle softness. Even though the collapse is far from perfect, the freezing-point scaling relationship provides a convenient and effective way to compare the structure and dynamics of fluid systems with different particle softness. We further show that an alternate scaling relationship based on two-body excess entropy can provide an almost perfect collapse of the diffusivity and viscosity data below the freezing transition. Next, we perform nonequilibrium molecular dynamics simulations to calculate the shear-dependent viscosity and to identify the distinct role of particle softness in underlying structural changes associated with rheological properties. Qualitatively, we find a similar shear-thinning behavior for IPP fluids with different particle softness, though softer particles exhibit stronger shear-thinning tendency. By investigating the distance and angle-dependent pair correlation functions in these systems, we find different structural features in the case of IPP fluids with hard-sphere like and softer particle interactions. Interestingly, shear-thinning in hard-sphere like fluids is accompanied by enhanced translational order, whereas softer fluids exhibit loss of order with shear. Our results provide a systematic evaluation

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances

Energy Technology Data Exchange (ETDEWEB)

Faybishenko, B. (ed.)

1999-02-01

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

Use of 3h-γ-aminobutyric acid for transport studies with isolated nerve-terminals from rat brain

International Nuclear Information System (INIS)

Halvarsson, G.B.; Karlsson, I.; Sellstroem, A.

1985-01-01

Isolated synaptosomes were used to study the problem of net accumulation of neurotransmitters. The time-course and the kinetics of exogenous and endogenous GABA transport were studied by liquid-scintillation counting and HPLC-amino acid analysis respectively. Different pools of GABA were suggested by a 6-fold difference in tissue-to-medium-ratio of endogenous vs. exogenous GABA. Net accumulation, exchange and net efflux of GABA was found to be a function of the GABA concentration in the incubation medium. The K/sub m/s for net accumulation and for 3 H-GABA accumulation were 2.68 +/- 1.16 and 6.19 +/- 1.26 μM respectively, whereas the V/sub max/s were 5.9 +/- 4.9 and 134 +/- 13 pmol/mg w.w min respectively. This means that the transport studies which use exogenous substances (e.g. 3 H-GABA) considerably overestimate the transport by overlooking the magnitude of the counter transport. 22 references, 5 figures, 2 tables

Fermi arc mediated entropy transport in topological semimetals

Science.gov (United States)

McCormick, Timothy M.; Watzman, Sarah J.; Heremans, Joseph P.; Trivedi, Nandini

2018-05-01

The low-energy excitations of topological Weyl semimetals are composed of linearly dispersing Weyl fermions that act as monopoles of Berry curvature in the bulk momentum space. Furthermore, on the surface there exist topologically protected Fermi arcs at the projections of these Weyl points. We propose a pathway for entropy transport involving Fermi arcs on one surface connecting to Fermi arcs on the other surface via the bulk Weyl monopoles. We present results for the temperature and magnetic field dependence of the magnetothermal conductance of this conveyor belt channel. The circulating currents result in a net entropy transport without any net charge transport. We provide results for the Fermi arc mediated magnetothermal conductivity in the low-field semiclassical limit as well as in the high-field ultraquantum limit, where only chiral Landau levels are involved. Our work provides a proposed signature of Fermi arc mediated magnetothermal transport and sets the stage for utilizing and manipulating the topological Fermi arcs in thermal applications.

Quantum net dynamics

International Nuclear Information System (INIS)

Finkelstein, D.

1989-01-01

The quantum net unifies the basic principles of quantum theory and relativity in a quantum spacetime having no ultraviolet infinities, supporting the Dirac equation, and having the usual vacuum as a quantum condensation. A correspondence principle connects nets to Schwinger sources and further unifies the vertical structure of the theory, so that the functions of the many hierarchic levels of quantum field theory (predicate algebra, set theory, topology,hor-ellipsis, quantum dynamics) are served by one in quantum net dynamics

High-level Petri Nets

DEFF Research Database (Denmark)

various journals and collections. As a result, much of this knowledge is not readily available to people who may be interested in using high-level nets. Within the Petri net community this problem has been discussed many times, and as an outcome this book has been compiled. The book contains reprints...... of some of the most important papers on the application and theory of high-level Petri nets. In this way it makes the relevant literature more available. It is our hope that the book will be a useful source of information and that, e.g., it can be used in the organization of Petri net courses. To make......High-level Petri nets are now widely used in both theoretical analysis and practical modelling of concurrent systems. The main reason for the success of this class of net models is that they make it possible to obtain much more succinct and manageable descriptions than can be obtained by means...

Local linear viscoelasticity of confined fluids.

Science.gov (United States)

Hansen, J S; Daivis, P J; Todd, B D

2007-04-14

In this paper the authors propose a novel method to study the local linear viscoelasticity of fluids confined between two walls. The method is based on the linear constitutive equation and provides details about the real and imaginary parts of the local complex viscosity. They apply the method to a simple atomic fluid undergoing zero mean oscillatory flow using nonequilibrium molecular dynamics simulations. The method shows that the viscoelastic properties of the fluid exhibit dramatic spatial changes near the wall-fluid boundary due to the high density in this region. It is also shown that the real part of the viscosity converges to the frequency dependent local shear viscosity sufficiently far away from the wall. This also provides valuable information about the transport properties in the fluid, in general. The viscosity is compared with predictions from the local average density model. The two methods disagree in that the local average density model predicts larger viscosity variations near the wall-fluid boundary than what is observed through the method presented here.

Reversal of diet-induced obesity increases insulin transport into cerebrospinal fluid and restores sensitivity to the anorexic action of central insulin in male rats.

Science.gov (United States)

Begg, Denovan P; Mul, Joram D; Liu, Min; Reedy, Brianne M; D'Alessio, David A; Seeley, Randy J; Woods, Stephen C

2013-03-01

Diet-induced obesity (DIO) reduces the ability of centrally administered insulin to reduce feeding behavior and also reduces the transport of insulin from the periphery to the central nervous system (CNS). The current study was designed to determine whether reversal of high-fat DIO restores the anorexic efficacy of central insulin and whether this is accompanied by restoration of the compromised insulin transport. Adult male Long-Evans rats were initially maintained on either a low-fat chow diet (LFD) or a high-fat diet (HFD). After 22 weeks, half of the animals on the HFD were changed to the LFD, whereas the other half continued on the HFD for an additional 8 weeks, such that there were 3 groups: 1) a LFD control group (Con; n = 18), 2) a HFD-fed, DIO group (n = 17), and 3) a HFD to LFD, DIO-reversal group (DIO-rev; n = 18). The DIO reversal resulted in a significant reduction of body weight and epididymal fat weight relative to the DIO group. Acute central insulin administration (8 mU) reduced food intake and caused weight loss in Con and DIO-rev but not DIO rats. Fasting cerebrospinal fluid insulin was higher in DIO than Con animals. However, after a peripheral bolus injection of insulin, cerebrospinal fluid insulin increased in Con and DIO-rev rats but not in the DIO group. These data provide support for previous reports that DIO inhibits both the central effects of insulin and insulin's transport to the CNS. Importantly, DIO-rev restored sensitivity to the effects of central insulin on food intake and insulin transport into the CNS.

Microfluidic device and methods for focusing fluid streams using electroosmotically induced pressures

Science.gov (United States)

Jacobson, Stephen C.; Ramsey, J. Michael

2010-06-01

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either electric current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to electrokinetically inducing fluid flow to confine a selected material in a region of a microchannel that is not influenced by an electric field. Other structures for inducing fluid flow in accordance with this invention include nanochannel bridging membranes and alternating current fluid pumping devices. Applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Fiscal 1996 achievement report. International Clean Energy Network Using Hydrogen Conversion (WE-NET) technology

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Research and development was performed for the WE-NET (World Energy Network) project which aims to carry out hydrogen production, transportation, and supply to consumers, by the use of renewable energy. Under subtask 1, the whole WE-NET project was subjected to evaluation, which included coordination between the respective tasks. Under subtask 2, information exchange and research cooperation were carried out with research institutes overseas. Under subtask 3, a conceptual design was prepared of a total system using ammonia as the medium for hydrogen transportation, accident data were collected and screened, and safety measures and evaluation techniques were developed and improved. Under subtask 4, the hot press method and the electroless plating method were selected as better electrode bonding methods. Under subtask 5, hydrogen liquefaction cycle processes, liquid hydrogen tankers, storage facilities, etc., were studied. Under subtasks 6-9, furthermore, investigations were conducted about low-temperature substance technology, hydrogen energy, hydrogen combustion turbine, etc. (NEDO)

Hazardous fluid leak detector

Science.gov (United States)

Gray, Harold E.; McLaurin, Felder M.; Ortiz, Monico; Huth, William A.

1996-01-01

A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.

Numerical modeling of fracking fluid migration through fault zones and fractures in the North German Basin

Science.gov (United States)

Pfunt, Helena; Houben, Georg; Himmelsbach, Thomas

2016-09-01

Gas production from shale formations by hydraulic fracturing has raised concerns about the effects on the quality of fresh groundwater. The migration of injected fracking fluids towards the surface was investigated in the North German Basin, based on the known standard lithology. This included cases with natural preferential pathways such as permeable fault zones and fracture networks. Conservative assumptions were applied in the simulation of flow and mass transport triggered by a high pressure boundary of up to 50 MPa excess pressure. The results show no significant fluid migration for a case with undisturbed cap rocks and a maximum of 41 m vertical transport within a permeable fault zone during the pressurization. Open fractures, if present, strongly control the flow field and migration; here vertical transport of fracking fluids reaches up to 200 m during hydraulic fracturing simulation. Long-term transport of the injected water was simulated for 300 years. The fracking fluid rises vertically within the fault zone up to 485 m due to buoyancy. Progressively, it is transported horizontally into sandstone layers, following the natural groundwater flow direction. In the long-term, the injected fluids are diluted to minor concentrations. Despite the presence of permeable pathways, the injected fracking fluids in the reported model did not reach near-surface aquifers, either during the hydraulic fracturing or in the long term. Therefore, the probability of impacts on shallow groundwater by the rise of fracking fluids from a deep shale-gas formation through the geological underground to the surface is small.

2-D fluid transport simulations of gaseous/radiative divertors

International Nuclear Information System (INIS)

Rognlien, T.D.; Brown, P.N.; Campbell, R.B.; Kaiser, T.B.; Knoll, D.A.; McHugh, P.R.; Porter, G.D.; Rensink, M.E.; Smith, G.R.

1994-01-01

The features of the fully implicit 2-D fluid code UEDGE are described. The utility of the code is demonstrated by showing bifurcations or multiple solutions of the tokamak edge plasma for both deuterium and impurity injection in the divertor. (orig.)

Closed-cycle gas turbine working fluids

International Nuclear Information System (INIS)

Lee, J.C.; Campbell, J. Jr.; Wright, D.E.

1981-01-01

Characteristic requirements of a closed-cycle gas turbine (CCGT) working fluid were identified and the effects of their thermodynamic and transport properties on the CCGT cycle performance, required heat exchanger surface area and metal operating temperature, cycle operating pressure levels, and the turbomachinery design were investigated. Material compatibility, thermal and chemical stability, safety, cost, and availability of the working fluid were also considered in the study. This paper also discusses CCGT working fluids utilizing mixtures of two or more pure gases. Some mixtures of gases exhibit pronounced synergetic effects on their characteristic properties including viscosity, thermal conductivity and Prandtl number, resulting in desirable heat transfer properties and high molecular weights. 21 refs

Planning of nets

International Nuclear Information System (INIS)

Carberry, M

1996-01-01

The paper is about the planning of nets in areas of low density like it is the case of the rural areas. The author includes economic and technological aspects, planning of nets, demands and management among others

Effects of Fluid Directions on Heat Exchange in Thermoelectric Generators

DEFF Research Database (Denmark)

Suzuki, Ryosuke; Sasaki, Yuto; Fujisaka, Takeyuki

2012-01-01

Thermal fluids can transport heat to the large surface of a thermoelectric (TE) panel from hot and/or cold sources. The TE power thus obtainable was precisely evaluated using numerical calculations based on fluid dynamics and heat transfer. The commercial software FLUENT was coupled with a TE model...... for this purpose. The fluid velocity distribution and the temperature profiles in the fluids and TE modules were calculated in two-dimensional space. The electromotive force was then evaluated for counter-flow and split-flow models to show the effect of a stagnation point. Friction along the fluid surface along...

Topology optimization of fluid mechanics problems

DEFF Research Database (Denmark)

Gersborg-Hansen, Allan

While topology optimization for solid continuum structures have been studied for about 20 years and for the special case of trusses for many more years, topology optimization of fluid mechanics problems is more recent. Borrvall and Petersson [1] is the seminal reference for topology optimization......D Navier-Stokes equation as well as an example with convection dominated transport in 2D Stokes flow. Using Stokes flow limits the range of applications; nonetheless, the present work gives a proof-of-concept for the application of the method within fluid mechanics problems and it remains...... processing tool. Prior to design manufacturing this allows the engineer to quantify the performance of the computed topology design using standard, credible analysis tools with a body-fitted mesh. [1] Borrvall and Petersson (2003) "Topology optimization of fluids in Stokes flow", Int. J. Num. Meth. Fluids...

Tidal and meteorological forcing of sediment transport in tributary mudflat channels.

Science.gov (United States)

Ralston, David K; Stacey, Mark T

2007-06-01

Field observations of flow and sediment transport in a tributary channel through intertidal mudflats indicate that suspended sediment was closely linked to advection and dispersion of a tidal salinity front. During calm weather when tidal forcing was dominant, high concentrations of suspended sediment advected up the mudflat channel in the narrow region between salty water from San Francisco Bay and much fresher runoff from the small local watershed. Salinity and suspended sediment dispersed at similar rates through each tidal inundation, such that during receding ebbs the sediment pulse had spread spatially and maximum concentrations had decreased. Net sediment transport was moderately onshore during the calm weather, as asymmetries in stratification due to tidal straining of the salinity front enhanced deposition, particularly during weaker neap tidal forcing. Sediment transport by tidal forcing was periodically altered by winter storms. During storms, strong winds from the south generated wind waves and temporarily increased suspended sediment concentrations. Increased discharge down the tributary channels due to precipitation had more lasting impact on sediment transport, supplying both buoyancy and fine sediment to the system. Net sediment transport depended on the balance between calm weather tidal forcing and perturbations by episodic storms. Net transport in the tributary channel was generally off-shore during storms and during calm weather spring tides, and on-shore during calm weather neap tides.

Programming NET Web Services

CERN Document Server

Ferrara, Alex

2007-01-01

Web services are poised to become a key technology for a wide range of Internet-enabled applications, spanning everything from straight B2B systems to mobile devices and proprietary in-house software. While there are several tools and platforms that can be used for building web services, developers are finding a powerful tool in Microsoft's .NET Framework and Visual Studio .NET. Designed from scratch to support the development of web services, the .NET Framework simplifies the process--programmers find that tasks that took an hour using the SOAP Toolkit take just minutes. Programming .NET

Role of field-induced nanostructures, zippering and size polydispersity on effective thermal transport in magnetic fluids without significant viscosity enhancement

Science.gov (United States)

Vinod, Sithara; Philip, John

2017-12-01

Magnetic nanofluids or ferrofluids exhibit extraordinary field dependant tunable thermal conductivity (k), which make them potential candidates for microelectronic cooling applications. However, the associated viscosity enhancement under an external stimulus is undesirable for practical applications. Further, the exact mechanism of heat transport and the role of field induced nanostructures on thermal transport is not clearly understood. In this paper, through systematic thermal, rheological and microscopic studies in 'model ferrofluids', we demonstrate for the first time, the conditions to achieve very high thermal conductivity to viscosity ratio. Highly stable ferrofluids with similar crystallite size, base fluid, capping agent and magnetic properties, but with slightly different size distributions, are synthesized and characterized by X-ray diffraction, small angle X-ray scattering, transmission electron microscopy, dynamic light scattering, vibrating sample magnetometer, Fourier transform infrared spectroscopy and thermo-gravimetry. The average hydrodynamic diameters of the particles were 11.7 and 10.1 nm and the polydispersity indices (σ), were 0.226 and 0.151, respectively. We observe that the system with smaller polydispersity (σ = 0.151) gives larger k enhancement (130% for 150 G) as compared to the one with σ = 0.226 (73% for 80 G). Further, our results show that dispersions without larger aggregates and with high density interfacial capping (with surfactant) can provide very high enhancement in thermal conductivity, with insignificant viscosity enhancement, due to minimal interfacial losses. We also provide experimental evidence for the effective heat conduction (parallel mode) through a large number of space filling linear aggregates with high aspect ratio. Microscopic studies reveal that the larger particles act as nucleating sites and facilitate lateral aggregation (zippering) of linear chains that considerably reduces the number density of space

Application of longshore transport equations to Andhra coast, East coast of India

Digital Repository Service at National Institute of Oceanography (India)

Chandramohan, P.; Nayak, B.U.; RamaRaju, V.S.

during November to February. The longshore transport rate is high during the southwest monsoon period from June to September. A higher sediment transport rate is observed for the coastline oriented at 80 degrees east of north. The annual net transport...

Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

Science.gov (United States)

Popic, Tony J; Davila, Yvonne C; Wardle, Glenda M

2013-01-01

Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2) area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo; Artina, Marco; Foransier, Massimo; Markowich, Peter A.

2015-01-01

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation

Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

Directory of Open Access Journals (Sweden)

S. Ahmad

2018-03-01

Full Text Available A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method. The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics. Keywords: Squeezing flow, Sutterby fluid model, Mixed convection, Double stratification, Thermal radiation, Chemical reaction

Influence of kinematic cuts on the net charge distribution

Energy Technology Data Exchange (ETDEWEB)

Petersen, Hannah [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Goethe Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Oliinychenko, Dmytro [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Bogolyubov Institute for Theoretical Physics, Kiev 03680 (Ukraine); Steinheimer, Jan [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Bleicher, Marcus [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Institut für Theoretische Physik, Goethe Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)

2016-12-15

The higher moments of the net charge distributions, e.g. the skewness and kurtosis, are studied within an infinite hadronic matter calculation in a transport approach. By dividing the box into several parts, the volume dependence of the fluctuations is investigated. After confirming that the initial distributions follow the expectations from a binomial distribution, the influence of quantum number conservation in this case the net charge in the system on the higher moments is evaluated. For this purpose, the composition of the hadron gas is adjusted and only pions and ρ mesons are simulated to investigate the charge conservation effect. In addition, the effect of imposing kinematic cuts in momentum space is analysed. The role of resonance excitations and decays on the higher moments can also be studied within this model. This work is highly relevant to understand the experimental measurements of higher moments obtained in the RHIC beam energy scan and their comparison to lattice results and other theoretical calculations assuming infinite matter.

A comparison of experiment, CEPXS/ONETRAN, TIGERP, and TIGER net electron emission coefficients for various bremsstrahlung spectra

International Nuclear Information System (INIS)

Ballard, W.P.; Lorence, L.J. Jr.; Snowden, D.P.; Van Lint, V.A.J.; Beale, E.S.

1987-01-01

This work compares a carefully designed experiment to measure photoemission with the predictions of three different codes (CEPXS/ONETRAN, TIGERP, and TIGER) for the complex bremsstrahlung spectra typical of very intense pulsed power x-ray generators. The Monte Carlo codes TIGER and TIGERP can calculate the net photon-induced electron emission but accurate results may require that statistical error be minimized. CEPXS/ONETRAN is a new deterministic coupled electron/photon transport code that is faster than Monte Carlo and is not subject to statistical error. The comparison of net yields is a sensitive test of the relative accuracy and efficiency of these various codes. The authors find that all of the codes substantially agree with the experiments for the forward net yields. However, for reverse net yields from high-Z materials, the codes overpredict relative to measurements

Physics of gas breakdown for ion beam transport in gas

International Nuclear Information System (INIS)

Olson, C.L.; Poukey, J.W.; Hinshelwood, D.D.; Rose, D.V.; Hubbard, R.F.; Lampe, M.; Neri, J.M.; Ottinger, P.F.; Slinker, S.P.; Stephanakis, S.J.; Young, F.C.; Welch, D.R.

1993-01-01

Detailed analysis, experiments, and computer simulations are producing a new understanding of gas breakdown during intense ion beam transport in neutral gas. Charge neutralization of beam micro clumps is shown to limit the net clump potentials to a non-zero value π min , which can lead to divergence growth and axial energy spreading. At pressures approx-gt 1 Torr, plasma shielding should substantially reduce this effect Current neutralization has been studied in experiments on the GAMBLE II accelerator. The importance of fast electrons (knockons and runaways) has been established in IPROP simulations, which are in agreement with the experiments. For light ion fusion parameters with pressures approx-gt 1 Torr, very small net current fractions (much-lt 1%) appear feasible, permitting ballistic transport in gas. Self-pinched requires higher net current fractions (≥ 2%) and preliminary IPROP code results indicate that this appears achievable for small-radius intense beams in lower pressure gases (approx-gt Torr). Several self-pinched transport concepts look promising. The importance of these results for both light ion fusion and heavy ion fusion is discussed

Net currents in the wave bottom boundary layer: on waveshape streaming and progressive wave streaming

NARCIS (Netherlands)

Kranenburg, Wouter; Ribberink, Jan S.; Uittenbogaard, R.E.; Hulscher, Suzanne J.M.H.

2012-01-01

The net current (streaming) in a turbulent bottom boundary layer under waves above a flat bed, identified as potentially relevant for sediment transport, is mainly determined by two competing mechanisms: an onshore streaming resulting from the horizontal non-uniformity of the velocity field under

Game Coloured Petri Nets

DEFF Research Database (Denmark)

Westergaard, Michael

2006-01-01

This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachability...... analysis of this net class, and an application of game coloured Petri nets to automatically generate easy-to-understand visualizations of the model by exploiting the knowledge that some parts of the model are not interesting from a visualization perspective (i.e. they are part of the environment...

Developments in tokamak transport modeling

International Nuclear Information System (INIS)

Houlberg, W.A.; Attenberger; Lao, L.L.

1981-01-01

A variety of numerical methods for solving the time-dependent fluid transport equations for tokamak plasmas is presented. Among the problems discussed are techniques for solving the sometimes very stiff parabolic equations for particle and energy flow, treating convection-dominated energy transport that leads to large cell Reynolds numbers, optimizing the flow of a code to reduce the time spent updating the particle and energy source terms, coupling the one-dimensional (1-D) flux-surface-averaged fluid transport equations to solutions of the 2-D Grad-Shafranov equation for the plasma geometry, handling extremely fast transient problems such as internal MHD disruptions and pellet injection, and processing the output to summarize the physics parameters over the potential operating regime for reactors. Emphasis is placed on computational efficiency in both computer time and storage requirements

Portable Intravenous Fluid Production Device for Ground Use

Data.gov (United States)

National Aeronautics and Space Administration — There are several medical conditions require the administration of intravenous (IV) fluids, but limitations of mass, volume, shelf-life, transportation, and local...

Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

Science.gov (United States)

Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

1997-01-01

The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

Fuel cell water transport

Science.gov (United States)

Vanderborgh, Nicholas E.; Hedstrom, James C.

1990-01-01

The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidify a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.

Movement of 125I albumin and 125I polyvinylpyrrolidone through bone tissue fluid

International Nuclear Information System (INIS)

Owen, M.; Howlett, C.R.; Triffitt, J.T.

1977-01-01

The passage of tissue fluid through cortical bone has been investigated using radioactively labelled macromolocules as markers. The results suggest that in the cortex of young rabbit femur the movement of tissue fluid is in the same net direction as blood, mainly from the endosteal to the periosteal surface. Some albumin is incorporated from extravascular tissue fluid into calcified matrix at sites of bone formation. Polyvinylpyrrolidone, average molecular weight 35,000, is able to pass through extravascular tissue fluid in bone but is not incorporated into calcified matrix. In rabbits made vitamin D deficient, much less albumin is retained in regions of bone formation than is the case with controls. Albumin adsorbs to the surface of calcium phosphate precipitates, and it is suggested that this mechanism may be mainly responsible for its incorporation into bone. (orig.) 891 AJ [de

On water transport in polymer electrolyte membranes during the passage of current

DEFF Research Database (Denmark)

Berning, Torsten

2011-01-01

This article discusses an approach to model the water transport in the membranes of PEM fuel cells during operation. Starting from a frequently utilized equation the various transport mechanisms are analyzed in detail. It is shown that the commonly used approach to simply balance the electro......-osmotic drag (EOD) with counter diffusion and/or hydraulic permeation is flawed, and that any net transport of water through the membrane is caused by diffusion. Depending on the effective drag the cathode side of the membrane may experience a lower hydration than the anode side. The effect of a water......-uptake layer on the net water transport will also be pictured. Finally, the effect of EOD is visualized using “Newton’s cradle”....

Blockade of the high-affinity noradrenaline transporter (NET) by the selective 5-HT reuptake inhibitor escitalopram: an in vivo microdialysis study in mice

Science.gov (United States)

Nguyen, Hai T; Guiard, Bruno P; Bacq, Alexandre; David, Denis J; David, Indira; Quesseveur, Gaël; Gautron, Sophie; Sanchez, Connie; Gardier, Alain M

2013-01-01

BACKGROUND AND PURPOSE Escitalopram, the S(+)-enantiomer of citalopram is the most selective 5-HT reuptake inhibitor approved. Although all 5-HT selective reuptake inhibitors (SSRIs) increase extracellular levels of 5-HT ([5-HT]ext). some also enhance, to a lesser extent, extracellular levels of noradrenaline ([NA]ext). However, the mechanisms by which SSRIs activate noradrenergic transmission in the brain remain to be determined. EXPERIMENTAL APPROACH This study examined the effects of escitalopram, on both [5-HT]ext and [NA]ext in the frontal cortex (FCx) of freely moving wild-type (WT) and mutant mice lacking the 5-HT transporter (SERT−/−) by using intracerebral microdialysis. We explored the possibilities that escitalopram enhances [NA]ext, either by a direct mechanism involving the inhibition of the low- or high-affinity noradrenaline transporters, or by an indirect mechanism promoted by [5-HT]ext elevation. The forced swim test (FST) was used to investigate whether enhancing cortical [5-HT]ext and/or [NA]ext affected the antidepressant-like activity of escitalopram. KEY RESULTS In WT mice, a single systemic administration of escitalopram produced a significant increase in cortical [5-HT]ext and [NA]ext. As expected, escitalopram failed to increase cortical [5-HT]ext in SERT−/− mice, whereas its neurochemical effects on [NA]ext persisted in these mutants. In WT mice subjected to the FST, escitalopram increased swimming parameters without affecting climbing behaviour. Finally, escitalopram, at relevant concentrations, failed to inhibit cortical noradrenaline and 5-HT uptake mediated by low-affinity monoamine transporters. CONCLUSIONS AND IMPLICATIONS These experiments suggest that escitalopram enhances, although moderately, cortical [NA]extin vivo by a direct mechanism involving the inhibition of the high-affinity noradrenaline transporter (NET). PMID:22233336

Scanning Probe Microscope-Based Fluid Dispensing

NARCIS (Netherlands)

Ghatkesar, M.K.; Perez Garza, H.H.; Heuck, F.; Staufer, U.

2014-01-01

Advances in micro and nano fabrication technologies have enabled fabrication of smaller and more sensitive devices for applications not only in solid-state physics but also in medicine and biology. The demand for devices that can precisely transport material, specifically fluids are continuously

Fluid transport with time on peritoneal dialysis: the contribution of free water transport and solute coupled water transport

NARCIS (Netherlands)

Coester, Annemieke M.; Smit, Watske; Struijk, Dirk G.; Krediet, Raymond T.

2009-01-01

Ultrafiltration in peritoneal dialysis occurs through endothelial water channels (free water transport) and together with solutes across small pores: solute coupled water transport. A review is given of cross-sectional studies and on the results of longitudinal follow-up

Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1991-01-01

This paper describes how Coloured Petri Nets (CP-nets) have been developed — from being a promising theoretical model to being a full-fledged language for the design, specification, simulation, validation and implementation of large software systems (and other systems in which human beings and...

Net zero water

CSIR Research Space (South Africa)

Lindeque, M

2013-01-01

Full Text Available the national grid. The unfortunate situation with water is that there is no replacement technology for water. Water can be supplied from many different sources. A net zero energy development will move closer to a net zero water development by reducing...

A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae

International Nuclear Information System (INIS)

Richers, Sherwood; Nagakura, Hiroki; Ott, Christian D.; Dolence, Joshua; Sumiyoshi, Kohsuke; Yamada, Shoichi

2017-01-01

The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, neutrino radiation transport is very difficult to simulate, and several radiation transport methods of varying levels of approximation are available. We carefully compare for the first time in multiple spatial dimensions the discrete ordinates (DO) code of Nagakura, Yamada, and Sumiyoshi and the Monte Carlo (MC) code Sedonu, under the assumptions of a static fluid background, flat spacetime, elastic scattering, and full special relativity. We find remarkably good agreement in all spectral, angular, and fluid interaction quantities, lending confidence to both methods. The DO method excels in determining the heating and cooling rates in the optically thick region. The MC method predicts sharper angular features due to the effectively infinite angular resolution, but struggles to drive down noise in quantities where subtractive cancellation is prevalent, such as the net gain in the protoneutron star and off-diagonal components of the Eddington tensor. We also find that errors in the angular moments of the distribution functions induced by neglecting velocity dependence are subdominant to those from limited momentum-space resolution. We briefly compare directly computed second angular moments to those predicted by popular algebraic two-moment closures, and we find that the errors from the approximate closures are comparable to the difference between the DO and MC methods. Included in this work is an improved Sedonu code, which now implements a fully special relativistic, time-independent version of the grid-agnostic MC random walk approximation.

A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae

Energy Technology Data Exchange (ETDEWEB)

Richers, Sherwood; Nagakura, Hiroki; Ott, Christian D. [TAPIR, Walter Burke Institute for Theoretical Physics, Mail code 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Dolence, Joshua [CCS-2, Los Alamos National Laboratory, P.O. Box 1663 Los Alamos, NM 87545 (United States); Sumiyoshi, Kohsuke [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Yamada, Shoichi, E-mail: srichers@tapir.caltech.edu [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

2017-10-01

The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, neutrino radiation transport is very difficult to simulate, and several radiation transport methods of varying levels of approximation are available. We carefully compare for the first time in multiple spatial dimensions the discrete ordinates (DO) code of Nagakura, Yamada, and Sumiyoshi and the Monte Carlo (MC) code Sedonu, under the assumptions of a static fluid background, flat spacetime, elastic scattering, and full special relativity. We find remarkably good agreement in all spectral, angular, and fluid interaction quantities, lending confidence to both methods. The DO method excels in determining the heating and cooling rates in the optically thick region. The MC method predicts sharper angular features due to the effectively infinite angular resolution, but struggles to drive down noise in quantities where subtractive cancellation is prevalent, such as the net gain in the protoneutron star and off-diagonal components of the Eddington tensor. We also find that errors in the angular moments of the distribution functions induced by neglecting velocity dependence are subdominant to those from limited momentum-space resolution. We briefly compare directly computed second angular moments to those predicted by popular algebraic two-moment closures, and we find that the errors from the approximate closures are comparable to the difference between the DO and MC methods. Included in this work is an improved Sedonu code, which now implements a fully special relativistic, time-independent version of the grid-agnostic MC random walk approximation.

Proteomic analysis of human norepinephrine transporter complexes reveals associations with protein phosphatase 2A anchoring subunit and 14-3-3 proteins

International Nuclear Information System (INIS)

Sung, Uhna; Jennings, Jennifer L.; Link, Andrew J.; Blakely, Randy D.

2005-01-01

The norepinephrine transporter (NET) terminates noradrenergic signals by clearing released NE at synapses. NET regulation by receptors and intracellular signaling pathways is supported by a growing list of associated proteins including syntaxin1A, protein phosphatase 2A (PP2A) catalytic subunit (PP2A-C), PICK1, and Hic-5. In the present study, we sought evidence for additional partnerships by mass spectrometry-based analysis of proteins co-immunoprecipitated with human NET (hNET) stably expressed in a mouse noradrenergic neuroblastoma cell line. Our initial proteomic analyses reveal multiple peptides derived from hNET, peptides arising from the mouse PP2A anchoring subunit (PP2A-Ar) and peptides derived from 14-3-3 proteins. We verified physical association of NET with PP2A-Ar via co-immunoprecipitation studies using mouse vas deferens extracts and with 14-3-3 via a fusion pull-down approach, implicating specifically the hNET NH 2 -terminus for interactions. The transporter complexes described likely support mechanisms regulating transporter activity, localization, and trafficking

Towards new information resources for public health--from WordNet to MedicalWordNet.

Science.gov (United States)

Fellbaum, Christiane; Hahn, Udo; Smith, Barry

2006-06-01

In the last two decades, WordNet has evolved as the most comprehensive computational lexicon of general English. In this article, we discuss its potential for supporting the creation of an entirely new kind of information resource for public health, viz. MedicalWordNet. This resource is not to be conceived merely as a lexical extension of the original WordNet to medical terminology; indeed, there is already a considerable degree of overlap between WordNet and the vocabulary of medicine. Instead, we propose a new type of repository, consisting of three large collections of (1) medically relevant word forms, structured along the lines of the existing Princeton WordNet; (2) medically validated propositions, referred to here as medical facts, which will constitute what we shall call MedicalFactNet; and (3) propositions reflecting laypersons' medical beliefs, which will constitute what we shall call the MedicalBeliefNet. We introduce a methodology for setting up the MedicalWordNet. We then turn to the discussion of research challenges that have to be met to build this new type of information resource. We build a database of sentences relevant to the medical domain. The sentences are generated from WordNet via its relations as well as from medical statements broken down into elementary propositions. Two subcorpora of sentences are distinguished, MedicalBeliefNet and MedicalFactNet. The former is rated for assent by laypersons; the latter for correctness by medical experts. The sentence corpora will be valuable for a variety of applications in information retrieval as well as in research in linguistics and psychology with respect to the study of expert and non-expert beliefs and their linguistic expressions. Our work has to meet several considerable challenges. These include accounting for the distinction between medical experts and laypersons, the social issues of expert-layperson communication in different media, the linguistic aspects of encoding medical knowledge, and

The influence of tip clearance on performance and internal flow condition of fluid food pump using low viscous fluid

International Nuclear Information System (INIS)

Kubo, S; Ishioka, T; Fukutomi, J; Shigemitsu, T

2012-01-01

Fluid machines for fluid food have been used in wide variety of fields i.e. transportation, the filling, and for the improvement of quality of fluid foods. However, flow conditions of it are quite complicated because fluid foods are different from water. Therefore, design methods based on internal flow conditions have not been conducted. In this research, turbo-pumps having a small number of blades were used to decrease shear loss and keep wide flow passage. The influence of the tip clearance was investigated by the numerical analysis using the model with and without the tip clearance. In this paper, the influence of tip clearance on performances and internal flow conditions of turbo-pump using low viscous fluid were clarified by experimental and numerical analysis results. In addition, design methods based on the internal flow were considered. Further, the influences of viscosity on the performance characteristic and internal flow were investigated.

Resistive wall tearing mode generated finite net electromagnetic torque in a static plasma

International Nuclear Information System (INIS)

Hao, G. Z.; Wang, A. K.; Xu, M.; Qu, H. P.; Peng, X. D.; Wang, Z. H.; Xu, J. Q.; Qiu, X. M.; Liu, Y. Q.

2014-01-01

The MARS-F code [Y. Q. Liu et al., Phys. Plasmas 7, 3681 (2000)] is applied to numerically investigate the effect of the plasma pressure on the tearing mode stability as well as the tearing mode-induced electromagnetic torque, in the presence of a resistive wall. The tearing mode with a complex eigenvalue, resulted from the favorable averaged curvature effect [A. H. Glasser et al., Phys. Fluids 18, 875 (1975)], leads to a re-distribution of the electromagnetic torque with multiple peaking in the immediate vicinity of the resistive layer. The multiple peaking is often caused by the sound wave resonances. In the presence of a resistive wall surrounding the plasma, a rotating tearing mode can generate a finite net electromagnetic torque acting on the static plasma column. Meanwhile, an equal but opposite torque is generated in the resistive wall, thus conserving the total momentum of the whole plasma-wall system. The direction of the net torque on the plasma is always opposite to the real frequency of the mode, agreeing with the analytic result by Pustovitov [Nucl. Fusion 47, 1583 (2007)]. When the wall time is close to the oscillating time of the tearing mode, the finite net torque reaches its maximum. Without wall or with an ideal wall, no net torque on the static plasma is generated by the tearing mode. However, re-distribution of the torque density in the resistive layer still occurs

Evaluation of the condensation potential of hydrocarbon fluids in the national gas pipeline system; establishing of adequate operational schemes

International Nuclear Information System (INIS)

Pineda Gomez, Cesar Augusto; Arenas Mantilla, Oscar Armando; Santos Santos, Nicolas

2007-01-01

For transporting industry of natural gas by pipeline systems, it's vital to guarantee the integrity of their lines, in order to decrease operational costs and prevent accidents that may damaging against people's safety, the environment or the infrastructure itself. in this paper it's presented the principal compounds from o technical study about principal net and its distribution branches to municipalities of the National System Transport of Natural Gas pointed by the Colombian Natural Gas Company - ECOGAS, (specifically the Cusiana - Porvenir - La Belleza, La Belleza - Cogua, La Belleza - Vasconia, Vasconia - Neiva and Vasconia - Cali gas lines, (see Figure 1). The principal objective is evaluate the possible condensation of hydrocarbons fluids inside gas lines, due to compositional characteristics of the gas, the different topographical conditions along the gas line route and the actual and future operational conditions to be implemented in the system. The evaluation performed over this gas streams, generates transcendental information in the creation of safe operational limits that minimizing the existence of obstacle problems and damages over pipeline systems and process equipment, due to the presence of liquid hydrocarbons inside these flow lines. This article has been prepared in four sections in order to guarantee easy access to each one of the steps involved in the study. Section one presents the compositional and thermodynamic analysis of feeding gas streams; in section two, its presented the required information for modeling gas lines with definition of the gas pipeline numerical simulation model in stable state; section three presents the sensitivity analysis for gas variation upon loading gas composition at the inlet point of the system, variation of the operational conditions (flow, pressure and gas temperature) and environment temperatures for the different inlet points (branches) with verification of compliance of the Unique Transport Regulation

Multiflavor string-net models

Science.gov (United States)

Lin, Chien-Hung

2017-05-01

We generalize the string-net construction to multiple flavors of strings, each of which is labeled by the elements of an Abelian group Gi. The same flavor of strings can branch, while different flavors of strings can cross one another and thus they form intersecting string nets. We systematically construct the exactly soluble lattice Hamiltonians and the ground-state wave functions for the intersecting string-net condensed phases. We analyze the braiding statistics of the low-energy quasiparticle excitations and find that our model can realize all the topological phases as the string-net model with group G =∏iGi . In this respect, our construction provides various ways of building lattice models which realize topological order G , corresponding to different partitions of G and thus different flavors of string nets. In fact, our construction concretely demonstrates the Künneth formula by constructing various lattice models with the same topological order. As an example, we construct the G =Z2×Z2×Z2 string-net model which realizes a non-Abelian topological phase by properly intersecting three copies of toric codes.

Chaotic-Dynamical Conceptual Model to Describe Fluid Flow and Contaminant Transport in a Fractured Vadose Zone

International Nuclear Information System (INIS)

Faybishenko, Boris; Doughty, Christine; Geller, Jil T.

1999-01-01

DOE faces the remediation of numerous contaminated sites, such as those at Hanford, INEEL, LLNL, and LBNL, where organic and/or radioactive wastes were intentionally or accidentally released to the vadose zone from surface spills, underground tanks, cribs, shallow ponds, and deep wells. Migration of these contaminants through the vadose zone has led to the contamination of (or threatens to contaminate) underlying groundwater. A key issue in choosing a corrective action plan to clean up contaminated sites is the determination of the location, total mass, mobility and travel time to receptors for contaminants moving in the vadose zone. These problems are difficult to solve in a technically defensible and accurate manner because contaminants travel downward intermittently, through narrow pathways, driven by variations in environmental conditions. These preferential flow pathways can be difficult to find and predict. The primary objective of this project is to determine if and when dynamical chaos theory can be used to investigate infiltration of fluid and contaminant transport in heterogeneous soils and fractured rocks. The objective of this project is being achieved through the following activities: Development of multi scale conceptual models and mathematical and numerical algorithms for flow and transport, which incorporate both (a) the spatial variability of heterogeneous porous and fractured media and (b) the temporal dynamics of flow and transport; Development of appropriate experimental field and laboratory techniques needed to detect diagnostic parameters for chaotic behavior of flow; Evaluation of chaotic behavior of flow in laboratory and field experiments using methods from non-linear dynamics; Evaluation of the impact these dynamics may have on contaminant transport through heterogeneous fractured rocks and soils and remediation efforts. This approach is based on the consideration of multi scale spatial heterogeneity and flow phenomena that are affected by

Transport biofuel yields from food and lignocellulosic C{sub 4} crops

Energy Technology Data Exchange (ETDEWEB)

Reijnders, L. [IBED University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam (Netherlands)

2010-01-15

In the near future, the lignocellulosic C{sub 4} crops Miscanthus and switchgrass (Panicum virgatum) are unlikely to outcompete sugarcane (Saccharum officinarum) in net energetic yearly yield of transport biofuel ha{sup -1}. This holds both for the thermochemical conversion into liquid hydrocarbons and the enzymatic conversion into ethanol. Currently, Miscanthus and switchgrass would also not seem able to outcompete corn (Zea mays) in net energetic yearly yield of liquid transport biofuel ha{sup -1}, but further development of these lignocellulosic crops may gradually lead to a different outcome. (author)

Controller Development for a Separate Meter-In Separate Meter-Out Fluid Power Valve for Mobile Applications

OpenAIRE

Nielsen, Brian

2005-01-01

In most mobile vehicles which are used within construction, agriculture, material handling, forestry, garbage handling etc. a fluid power system is used for power transport and power distribution. The transported/distributed power is usually generated by a diesel engine or from an electrical battery. The largest advantages of the fluid power system are its high energy density and its robustness. Currently there is no cost effective and robust alternative to using a fluid power system for the ...

Rare, but challenging tumors: NET

International Nuclear Information System (INIS)

Ivanova, D.; Balev, B.

2013-01-01

Full text: Introduction: Gastroenteropancreatic Neuroendocrine Tumors (GEP - NET) are a heterogeneous group of tumors with different locations and many different clinical, histological, and imaging performance. In a part of them a secretion of various organic substances is present. The morbidity of GEP - NET in the EU is growing, and this leads to increase the attention to them. What you will learn: Imaging methods used for localization and staging of GEP - NET, characteristics of the study’s protocols; Classification of GEP - NET; Demonstration of typical and atypical imaging features of GEP - NET in patients registered at the NET Center at University Hospital ‘St. Marina’, Varna; Features of metastatic NET, The role of imaging in the evaluation of treatment response and follow-up of the patients. Discussion: The image semiotics analysis is based on 19 cases of GEP - NET registered NET Center at University Hospital ‘St. Marina’. The main imaging method is multidetector CT (MDCT), and magnetic resonance imaging (MRI ) has advantages in the evaluation of liver lesions and the local prevalence of anorectal tumors. In patients with advanced disease and liver lesions the assessment of skeletal involvement (MRI/ nuclear medical method) is mandatory. The majority of GEP - NET have not any specific imaging findings. Therefore it is extremely important proper planning and conducting of the study (MDCT and MR enterography; accurate assessment phase of scanning, positive and negative contrast). Conclusion: GEP - NET is a major diagnostic challenge due to the absence of typical imaging characteristics and often an overlap with those of the tumors of different origin can be observed. Therefore, a good knowledge of clinical and imaging changes occurring at different locations is needed. MDCT is the basis for the diagnosis, staging and follow-up of these neoplasms

The source of net ultrafiltration during hemodialysis is mostly the extracellular space regardless of hydration status.

Science.gov (United States)

Jeong, Hyeonju; Lim, Chae-Wan; Choi, Hye-Min; Oh, Dong-Jin

2016-01-01

Fluid shifts are common in patients undergoing chronic hemodialysis (HD) during the intradialytic periods, as several liters of fluid are removed during ultrafiltration (UF). Some patients have experienced frequent intradialytic hypotension (IDH). However, the characteristics of fluid shifts and which fluid space is affected remain controversial. Therefore, we designed this study to evaluate the fluid spaces most affected by UF and to determine whether hydration status influences the fluid shifts during HD. This was a prospective cohort study of 40 patients undergoing HD. We measured the patient's fluid spaces using a whole-body bioimpedance apparatus to evaluate the changes in the fluid spaces before HD and 1-4 hours of HD and 30 minutes after HD. UF achieved during HD by the 40 patients (age, 60.0 ± 5.2 years; 50% men; 50% of patients with diabetes; body weight, 61.3 ± 10.5 kg) was 2.18 ± 0.78 L (measured fluid overload, 2.15 ± 1.24 L). 1) Mean relative reduction of total body water and extracellular water was reduced from the start to the end of HD. 2) However, mean relative reduction of intracellular water was not reduced from the start to the end of HD. 3) No significant differences in fluid shifts were observed according to hydration status. The source of net UF during HD is mostly the extracellular space regardless of hydration status. Thus, IDH may be related to differences in the interstitial fluid shift to the vascular space. © 2015 International Society for Hemodialysis.

On deriving transport pathways and morphodynamics in a tidal inlet from high-resolution MBES and LiDAR surveys: the Knudedyb tidal inlet in the Danish Wadden Sea

DEFF Research Database (Denmark)

Ernstsen, Verner Brandbyge; Lefebvre, Alice; Fraccascia, Serena

and topobathymetric surveys using high-resolution red and green Light Detection And Ranging (LiDAR), respectively. Detailed digital elevation models with a grid cell size of 1 m x 1 m were generated and analysed geomorphometrically. The analyses reveal a main ebb-directed net sand transport in the main channel......; however, due to the geometry of the main channel, displaying a confluent meander bend, confined areas in the main channel are characterised by an opposite-directed net sand transport. In the inter-tidal areas the main net sand transport is flood-directed. However, also here the analyses reveal...... that during storm events with winds from SW, sand is transported from the inlet channel to the intertidal flat. Hence, in addition to the typical main sand transport directions with net export in the inlet channel and net import over the adjacent inter-tidal flats, these investigations suggest an exchange...

Limitations of shallow nets approximation.

Science.gov (United States)

Lin, Shao-Bo

2017-10-01

In this paper, we aim at analyzing the approximation abilities of shallow networks in reproducing kernel Hilbert spaces (RKHSs). We prove that there is a probability measure such that the achievable lower bound for approximating by shallow nets can be realized for all functions in balls of reproducing kernel Hilbert space with high probability, which is different with the classical minimax approximation error estimates. This result together with the existing approximation results for deep nets shows the limitations for shallow nets and provides a theoretical explanation on why deep nets perform better than shallow nets. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of common methods for sampling invertebrate pollinator assemblages: net sampling out-perform pan traps.

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Tony J Popic

Full Text Available Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2 area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

A long-distance fluid transport pathway within fibrous connective tissues in patients with ankle edema.

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Li, Hongyi; Yang, Chongqing; Lu, Kuiyuan; Zhang, Liyang; Yang, Jiefu; Wang, Fang; Liu, Dongge; Cui, Di; Sun, Mingjun; Pang, Jianxin; Dai, Luru; Han, Dong; Liao, Fulong

2016-10-05

Although the microcirculatory dysfunctions of edema formation are well documented, the draining pattern of dermal edema lacks information. This study was to assess the potential drainage pathways of the interstitial fluid in patients with ankle edema using the anatomical and histological methods. Four amputees of lower leg participated in this study. Fluorescent imaging agent was injected into lateral ankle dermis in one volunteered patient before the amputation and three lower legs after the amputation. Physiologically in the volunteer or enhanced by cyclical compression on three amputated limbs, several fluorescent longitudinal pathways from ankle dermis to the broken end of the amputated legs were subsequently visualized and studied using histological methods, laser confocal microscopy and electron microscopy methods respectively. Interestingly, the fluorescent pathways confirmed to be fibrous connective tissues and the presence of two types: those of the cutaneous pathway (located in dermis or the interlobular septum among adipose tissues within the hypodermis) and those of the perivascular pathway (located in connective tissues surrounding the veins and the arteries). The intrinsic three-dimensional architecture of each fluorescent pathway was the longitudinally running and interconnected fibril bundles, upon which, an interfacial transport pathway within connective tissues was visualized by fluorescein. The current anatomical data suggested that a unique long-distance transport pathway composed of oriented fibrous connective tissues might play a pathophysiological role in draining dermal edema besides vascular circulations and provide novel understandings of general fibrous connective tissues in life science.

The effect of netting solidity ratio and inclined angle on the hydrodynamic characteristics of knotless polyethylene netting

Science.gov (United States)

Tang, Hao; Hu, Fuxiang; Xu, Liuxiong; Dong, Shuchuang; Zhou, Cheng; Wang, Xuefang

2017-10-01

Knotless polyethylene (PE) netting has been widely used in aquaculture cages and fishing gears, especially in Japan. In this study, the hydrodynamic coefficient of six knotless PE netting panels with different solidity ratios were assessed in a flume tank under various attack angles of netting from 0° (parallel to flow) to 90° (perpendicular to flow) and current speeds from 40 cm s-1 to 130 cm s-1. It was found that the drag coefficient was related to Reynolds number, solidity ratio and attack angle of netting. The solidity ratio was positively related with drag coefficient for netting panel perpendicular to flow, whereas when setting the netting panel parallel to the flow the opposite result was obtained. For netting panels placed at an angle to the flow, the lift coefficient reached the maximum at an attack angle of 50° and then decreased as the attack angle further increased. The solidity ratio had a dual influence on drag coefficient of inclined netting panels. Compared to result in the literature, the normal drag coefficient of knotless PE netting measured in this study is larger than that of nylon netting or Dyneema netting.

International Clean Energy System Using Hydrogen Conversion (WE-NET). subtask 2. Research study on promotion of international cooperation; Suiso riyo kokusai clean energy system gijutsu (WE-NET). subtask 2. Kokusai kyoryoku suishin no tame no chosa kento

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

This paper describes the research result on promotion of international cooperation in the WE-NET project in fiscal 1996. The WE-NET project aims at development of the total system for hydrogen production, transport, storage and utilization, and construction of the earth-friendly innovative global clean energy network integrating elemental technologies. Since the standpoint is different between latent resource supplying countries and technology supplying countries, the WE-NET project should be constantly promoted under international understanding and cooperation. The committee distributed the annual summary report prepared by NEDO to overseas organizations, and made positive PR activities in the 11th World Conference and others. The committee made the evaluation on the improvement effect of air pollution by introducing a hydrogen vehicle in combination with Stanford University, and preparation of PR video tapes for hydrogen energy. Preliminary arrangement of Internet home pages, establishment of a long-term vision for international cooperation, and proposal toward the practical WE-NET are also made. 9 figs., 13 tabs.

Use of bed nets and factors that influence bed net use among Jinuo Ethnic Minority in southern China.

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Xu, Jian-wei; Liao, Yuan-mei; Liu, Hui; Nie, Ren-hua; Havumaki, Joshua

2014-01-01

Insecticide-treated nets (ITNs) are an integral part of vector control recommendations for malaria elimination in China. This study investigated the extent to which bed nets were used and which factors influence bed net use among Jinuo Ethnic Minority in China-Myanmar-Laos border areas. This study combined a quantitative household questionnaire survey and qualitative semi-structured in-depth interviews (SDI). Questionnaires were administered to 352 heads of households. SDIs were given to 20 key informants. The bed net to person ratio was 1∶2.1 (i.e., nearly one net for every two people), however only 169 (48.0%) households owned at least one net and 623 (47.2%) residents slept under bed nets the prior night. The percentages of residents who regularly slept under nets (RSUN) and slept under nets the prior night (SUNPN) were similar (48.0% vs. 47.2%, P>0.05), however the percentage correct use of nets (CUN) was significantly lower (34.5%, Pcash income per person (ACIP) was an independent factor that influenced bed net use (PHigh bed net availability does not necessarily mean higher coverage or bed net use. Household income, house type and knowledge of the ability of bed nets to prevent malaria are all independent factors that influence bed net use among Jinuo Ethnic Minority.